The angiosperm pollen tube delivers two sperm cells into the embryo sac through a unique growth strategy, named tip growth, to accomplish fertilization. A great deal of experiments have demonstrated that actin bundles play a pivotal role in pollen tube tip growth. There are two distinct actin bundle populations in pollen tubes: the long, rather thick actin bundles in the shank and the short, highly dynamic bundles near the apex. With the development of imaging techniques over the last decade, great breakthroughs have been made in understanding the function of actin bundles in pollen tubes, especially short subapical actin bundles. Here, we tried to draw an overall picture of the architecture, functions and underlying regulation mechanism of actin bundles in plant pollen tubes. In the sexual reproduction of angiosperms, firstly, the pollen grain hydrates and produces the pollen tube. Then, it passes through the column and reaches the micropyle via apical growth. After entering the embryo sac, the pollen tube releases two sperms. Finally, the double fertilization process is completed . In thisEarly studies have shown that the actin skeleton plays a vitally important role in the tip growth of pollen tubes ,3. The gThe actin in vivo can be present as either a free monomer called the G-actin (globular) or as part of a linear polymer microfilament called the F-actin (filamentous) . The G-aIn plant cells, the F-actin has many distinct architectures regulated by a variety of actin-binding proteins, such as foci, rings, and meshwork ,32,33,34pLat52::Lifeact-GFP transgenic pollen tubes, when tracing the dynamics of individual actin filaments, the maximal filament length substantially increased and the severing frequency substantially decreased in comparison to that in the apical region [The pollen tube is characterized by at least two types of actin bundles, which roughly correspond to the sub-apex and the shank. In the shank, the long and thick actin bundles are parallel with the axis of pollen tubes, with some of the bundles even extending close to the subapical area but without penetrating into the subapical region ,37,38. Cl region . By repll region . Furtherl region . Myosin,l region ,42.Arabidopsis, tobacco, and lily [The actin organization in the apical domain of lily pollen was clearly revealed in 2005 by the Hepler group. They confirmed that actin bundles do exist in the sub-apex, and can form a dense cortical fringe or collar starting about 1–5 μm behind the extreme apex and extending basally for an additional 5–10 μm . Subsequand lily ,33,43,44and lily . By usinand lily , and theand lily . These sand lily . Recent and lily ,45, and,and lily , while tand lily .In summary, the two types of actin bundles, which roughly correspond to the shank and the sub-apex in pollen tubes, ensure orderly vesicle transport from the base to the tip, thus guaranteeing rapid tip growth.Proper actin cytoskeleton organization is important for the polarity growth of pollen tubes. Within the tubes, the assembly and disassembly of the actin filaments are promoted by many actin-binding proteins (ABPs), including nucleating, depolymerizing, severing, capping, F-actin stabilizing, and G-actin sequestering proteins ,9,47. Am2+.Plant villins, which contain multiple 15 kDa gelsolin/severin domains, belong to the villin/gelsolin/fragmin superfamily. In addition to the six gelsolin domains, villin has a head domain at the C-terminal, providing an additional microfilament binding site . This su2+-induced actin fragmentation and disrupts the brush border, which means that villins are essential for mouse actin rearrangement after stimulation [In mice, the deletion of villins prevents Camulation . Mutatiomulation ,52.Lilium longiflorum) by biochemical fractionation [2+/ Ca2+-calmodulin (CaM) [2+ [P-135-ABP and P-115-ABP isolated from lily  . To explin (CaM) . FurtherCaM) [2+ .Arabidopsis, named AtVLN1 to AtVLN5 [vln2 vln5 [2+ concentration, while it severs and caps microfilaments under a higher concentration of Ca2+. In the atvln4 mutant, the root hairs are shorter and the actin bundles in the hair cells are fewer in comparison to the wild type [There are five villin-like genes in o AtVLN5 . Two of o AtVLN5 ,63. For o AtVLN5 ,62. The ln2 vln5 . In addiild type .Microfilament polymerization is mainly initiated by nucleation factors. There are two classes of nucleation factors, formin and the Arp2/3 complex. Formin launches linearly arranged microfilaments, while the Arp2/3 complex forms reticular microfilaments. However, neither the growth of pollen tubes nor the development of root hairs is dramatically affected in four of arp mutants grown under normal conditions . ForminsArabidopsis. It can be divided into two groups, according to sequence similarity and conservatism. Group I has a unique N-terminal, which includes a proline-rich, potentially glycosylated extracellular domain and a transmembrane domain [Arabidopsis, including 11 members (AtFH 1-11) in group I and 10 members (AtFH12-21) in group II [Unlike other actin bundlers, formins have a large number of homologous variants in the model plant e domain . There agroup II . Rice hagroup II .Up to now, several plant formins, including AtFH1, AtFH8, AtFH14, AtFH16, OsFH5, and LlFH1, have been verified to bundle actin filaments ,72,73,74Schizosaccharomyces pombe assembles actin bundles oriented parallel to the long axis of cells for polarization. When deprived of the fimbrin homologous protein FIM1, the cells have mild polarity defects with their actin bundles appearing to be qualitatively more randomly oriented [Aspergillus nidulans, the disruption of the fimbrin homolog protein FIMA results in delayed polarity establishment, abnormal hyphal growth, and endocytic defects in apolar cells [Fimbrin, also named plastin, is a well-characterized actin-bundling protein conserved in eukaryotes. It has been demonstrated that fimbrin is involved in polar growth across different species. For example, the fission yeast oriented . In Aspear cells . In mammar cells .Arabidopsis genome. Microarray data predict that AtFIM3, AtFIM4, and AtFIM5 are expressed in pollens, with AtFIM4 and AtFIM5 being most abundant [Five fimbrin-like genes, FIM1–FIM5, are present in the abundant . Only Atabundant . When knabundant ,82. AtFIabundant .Plant LIM proteins are a family of actin-bundling proteins with LIM domains interacting directly with actin filaments ,85,86,87Nicotiana tabacum WLIM1 is an actin-binding protein in plants [(Lilium longiflorum) pollen-enriched LIM protein, LlLIM1, was also explored. Cytological and biochemical assays verified that LlLIM1 promoted filamentous actin bundle assembly and protected F-actin against latrunculin B-mediated depolymerization. Furthermore, its actin-binding affinity is simultaneously regulated by both pH and Ca2+ [By using confocal microscopy, Thomas et al. were the first to show that n plants . Later, and Ca2+ . Pollen and Ca2+ . TherefoArabidopsis genome contains six genes encoding LIM proteins, three of which are predominantly expressed in pollen: PLIM2a, PLIM2b, and PLIM2c [Arabidopsis pollen development and tube growth [The d PLIM2c ,92. The d PLIM2c . The knod PLIM2c . These ad PLIM2c . PLIM2b d PLIM2c . Differed PLIM2c . Collecte growth .Arabidopsis with a homology as high as 71%. CROLINl and CROLIN2 are specifically expressed in pollen, while CROLIN3-CROLIN6 are expressed in the vegetative organs. Biochemical analyses showed that CROLIN1 is a novel actin cross-linking protein with binding and stabilizing activities [The plant-specific CROLIN family contains one or two predicted actin cross-linking domains. There are six CROLIN members in tivities . Moreovetivities . In the tivities .The ACTIN-DEPOLYMERIZING FACTOR (ADF/cofilin) family is an important class of low-molecular-weight actin-binding proteins that exists in all eukaryotes . ADF wasIn lily and tobacco pollen tubes, both green fluorescent protein (GFP)-ADF and immunocytochemistry with anti-ADF sera decorate actin filaments and show an accumulation of ADF in the cortical cytoplasm of the subapical region ,106,107.Arabidopsis genome, and these genes can be divided into four subclasses [Arabidopsis ADF5 and ADF9 evolved a F-actin-bundling (B-type) function from a conserved F-actin-depolymerizing (D-type) function [adf5 pollen, which thus delayed the establishment of polarity [adf5 pollen tubes was hypersensitive to LatB, and the skewness value was significantly decreased in adf5 pollen grains, indicating that the extent of actin bundling was decreased due to ADF5 deficiency [adf5adf9 double mutant and the adf5 mutant [There are 11 ADF genes encoded by the bclasses . Subclasbclasses . Subclasbclasses ,110. Subbclasses . Furtherbclasses . The sinbclasses . In subcbclasses ,109. Grebclasses . ADF7 inbclasses . ADF7 prbclasses . In adf7bclasses . These rbclasses . On the bclasses ,112. Thefunction . There wpolarity . The actficiency . Accordificiency . However5 mutant . These d5 mutant .So far, six different actin-binding proteins families have been studied using the model plant Arabidopsis as a research object. All of them have at least two homologous members in the pollen tube.Are the homologous members performing the same function? In In the next decade, it is necessary to explore the properties of actin bundles of pollen tubes in detail, and to uncover how the six actin-binding proteins families corporately function to ensure proper actin bundle construction in pollen tubes.


Subsequently, DNA damage responses and other cellular responses are initiated. In plants, poly(ADP-ribose) polymerases (PARPs) have also been implicated in responses to DNA damage. The Arabidopsis genome contains three canonical PARP genes, the nomenclature of which has been uncoordinated in the past. Albeit assumptions concerning the function and roles of PARP proteins in planta have often been inferred from homology and structural conservation between plant PARPs and their mammalian counterparts, plant-specific roles have become apparent. In particular, PARPs have been linked to stress responses of plants. A negative role under abiotic stress has been inferred from studies in which a genetic or, more commonly, pharmacological inhibition of PARP activity improved the performance of stressed plants; in response to pathogen-associated molecular patterns, a positive role has been suggested. However, reports have been inconsistent, and the effects of PARP inhibitors appear to be more robust than the genetic abolition of PARP gene expression, indicating the presence of alternative targets of those drugs. Collectively, recent evidence suggests a conditionality of stress-related phenotypes of parp mutants and calls for a reconsideration of PARP inhibitor studies on plants. This review critically summarizes our current understanding of poly(ADP-ribosylation) and PARP proteins in plants, highlighting similarities and differences to human PARPs, areas of controversy, and requirements for future studies.Poly(ADP-ribosyl)ation is a rapid and transient post-translational protein modification that was described first in mammalian cells. Activated by the sensing of DNA strand breaks, poly(ADP-ribose)polymerase1 (PARP1) transfers ADP-ribose units onto itself and other target proteins using NAD T,9. T8,9]e lethal ,77. Simie lethal ,79. ARH3e lethal ,79. The e lethal ,81,82.3H]NAD into nuclei of onion and wheat embryo cells and onion meristematic root tissues [In the late 1970s, poly(ADP-ribosyl)ation activity was shown in higher plants by the incorporation of [ tissues ,84,85,86 tissues . Lysine- tissues . In addi tissues ,88. PARP gene identified in plants was Arabidopsis thaliana APP (At4g02390) [AtPARP2 cDNA was identified due to its 62% similarity to the catalytic domain of human PARP1 during experiments carried out to identify Arabidopsis proteins that allow yeast cells to grow under stress conditions. The AtPARP2 protein consists of 637 amino acids and has a size of 72 kDa. The PARP signature is conserved in AtPARP2. Apart from that, a nuclear localization signal and an automodification domain were found. In contrast to human PARP1, which possesses N-terminal zinc-finger domains, AtPARP2 contains an N-terminal SAP domain ating activity. The main polymer size was 10 to 15 residues, but polymers of up to 40 ADP-ribosyl residues were formed [Nicotiana benthamiana and Arabidopsis [AtPARP2 expression in imbibed seeds, the vegetative meristem of the shoot apex, stamen of open flowers, and late stages of embryo development [The first 4g02390) . In thisP domain . The SAPe formed . The polbidopsis ,93,94. IAtPARP1 (At2g31320) was identified in a screen for ionizing radiation-induced genes in Arabidopsis thaliana [AtPARP1 expression inhibited yeast cell growth similarly to HsPARP1 [thaliana . AtPARP1 HsPARP1 . Growth  HsPARP1 .Nicotiana benthamiana and in Arabidopsis cell suspension culture [Arabidopsis protoplasts [AtPARP1 promoter with GUS and RNA hybridization analyses revealed expression of AtPARP1 in the roots, apices of inflorescences, vegetative meristem, and during the late stages of embryo development [Like AtPARP2, AtPARP1-GFP was found to localize to the nucleus in  culture ,93. AddiArabidopsis PARP1 and PARP2 genes and proteins has been inconsistent in the literature , which was first identified by Arabidopsis genome analysis. It was mainly expressed in seeds, but also in seedlings and roots of adult plants [AtPARP3 was strongly induced  in leaves by severe abiotic stress in the form of paraquat, NaCl, high light, or desiccation [So far, less is known about t plants ,109,110.iccation . PARP3-Giccation ,110, andiccation . AtPARP1 in yeast cells, AtPARP2 inhibited yeast growth only partially, while AtPARP3 expression did not affect growth [HsPARP2 expression causes an inhibition of yeast growth [Arabidopsis and human PARPs share structural or functional features, but also pointed to plant-specific functions of AtPARP2 and AtPARP3.In contrast to the expression of t growth . This mat growth . The difPARG have been identified in Arabidopsis thaliana [AtPARG1 (At2g31870) and AtPARG2 (At2g31865), are localized in tandem on chromosome 2.In total, three genes with homology to human thaliana . For oneArabidopsis, both PARG proteins are localized in the nucleus, the cytoplasm, and at the plasma membrane [Arabidopsis [tej mutants also flowered earlier. These phenotypes suggest a general clock defect, making AtPARG1 a component of clock function in plants. Poly(ADP-ribose) polymer levels were increased in the tej mutants suggesting that AtPARG1 is a bona fide PARG [32P-NAD+ revealed that recombinant AtPARG1 is able to remove poly(ADP-ribose) from automodified AtPARP2. Similarly, co-expression of AtPARP2 and AtPARG1 in Arabidopsis protoplasts led to a significant removal of poly(ADP-ribose) from automodified AtPARP2. In contrast to this, no poly(ADP-ribose)glycohydrolase activity towards automodified AtPARP2 or AtPARP1 was found for AtPARG2 in vitro and in vivo. This lack of activity could not be exclusively attributed to the presence of a polymorphism in the conserved PARG signature motif in PARG2, since a recombinant PARG2 protein carrying the conserved PARG motif did also not show any detectable poly(ADP-ribose) glycohydrolase activity. Therefore, additional deviations in the protein sequence of AtPARG1 and AtPARG2 are thought to account for the differences in enzyme activity [In membrane ,108. AtPbidopsis . Mutant ide PARG . Poly or cisplatin (an inhibitor of DNA replication by cross-linking neighboring guanine bases) in Arabidopsis [AtPARP3 expression was only induced in the absence of AtPARP1 or AtPARP2 [HvPARP3 expression was induced in barley roots in response to bleomycin (a glycopeptide that mainly induces DSB) [AtPARP expression, PARP activity was induced by DNA-damaging agents, such as zeocin and X-ray irradiation [During about 40 years of work on poly(ADP-ribosyl)ation in plants, various studies showed that plant PARP proteins are components of DNA damage responses similar to their mammalian counterparts. The expression of bidopsis ,97,113. ces DSB) . Similaradiation ,116. Recadiation ,101,116.adiation ,116.parp1 and parp2 mutant plants enhanced the sensitivity of plant growth to methyl methane sulfonate ) and to bleomycin [parp2 seedlings grown on bleomycin and mitomycin C (a DNA cross-linking agent) [parp2 mutants are more sensitive to DNA-damaging agents than parp1 mutants [parp2, but not in parp1 mutants [parp1 parp2 double mutants compared to the corresponding single mutants, indicating that both AtPARP genes are involved in responses to DNA-damaging agents [AtPARP1 in parp2 mutants and vice versa [parp1 parp2 parp3 triple mutants, indicating that AtPARP3 is not active in DNA damage response in seedlings [HvPARP3 mutation led to an altered root growth response to bleomycin [parp mutants under genotoxic stress may be explained by aggravated DNA damage. In agreement with increased gene expression and activity, the genetic inhibition of AtPARPs in leomycin ,108,117.g agent) . Some au mutants ,97. In l mutants . Increasg agents ,108. Thice versa ,92,97. Ace versa . No exacleomycin . In summPseudomonas syringae pv. tomato (Pst) was shown to induce DNA damage [parp2 and parp1 parp2 mutants in response to treatment with Pst [In addition to DNA-damaging agents, infection of plants with the bacterium A damage . In linewith Pst .Arabidopsis parp mutants to various DNA-damaging agents showed that plant PARPs are important actors in DNA damage responses, similar to their human counterparts. In line with this, the ionizing radiation-mediated induction of AtPARP2 was found to depend on the presence of ATM, as the induction was absent in atm mutant plants [AtRAD51 and AtXRCC3 was enhanced by 3AB treatment [AtPARP2 was induced in mms21-1 mutant plants, while homologous recombination events were found to be reduced in this mutant [AtMMS21 encodes a SUMO E3 ligase, a critical component of the SMC5/6 complex which fulfills a central role in genome stability maintenance [AtXRCC2, another component of HR, was found to be reduced upon 3AB treatment [The exacerbated sensitivity of t plants . ATM is t plants   at the ends of broken DNA strands in ku80 and parp1 parp2 ku80 than in parp1 parp2 mutants. So, resection of nucleotides from the DNA ends occurred mainly in the ku80 and parp1 parp2 ku80 mutants. An alternative NHEJ pathway in ku80 mutants is microhomology-mediated end-joining (MMEJ). A higher level of MMEJ products were found in ku mutants compared to parp1 parp2 or parp1 parp2 ku80 mutants, indicating that PARPs are involved in MMEJ [Another study indicated that PARPs are involved in an error-prone alternative pathway of NHEJ like their mammalian counterparts . Triple  mutants . Additio in MMEJ . In cont in MMEJ .parp1 rad5a double mutant was more sensitive to the DNA-alkylating agent MMS than the corresponding single mutant plants [parp1 rad5a did not display enhanced sensitivity to the crosslinking agents cisplatin and mitomycin C as compared to the rad5a mutant plants. No enhanced sensitivity to either agent was observed in the parp1 mutant compared to wild type plants. These findings suggested that AtPARP1 is involved in the repair of base alkylations in a pathway parallel to that involving RAD5a, which possibly corresponds to base excision repair (BER) and HR-independent single strand break repair [XRCC1 expression [AtPARP2 expression is induced in the absence of Ligase1, another component of BER, indicating that AtPARP2 also interacts with the BER pathway [Recently, one function of AtPARP1 in DNA damage responses was further clarified. A t plants . By contk repair . In linepression . XRCC1 ipression . AtPARP2 pathway . Arabidopsis plants, AtPARP3 was suggested to be either inactive or not involved in DNA damage responses [AtPARP3 transcripts specifically in the embryo and the endosperm of dry seeds, during imbibition, and during seed germination [PARP3 orthologue in rice [AtPARP3 promoter activity coincided with reactive oxygen species (ROS) accumulation in the embryo and that parp3 mutant seeds lose viability upon prolonged storage or upon artificial ageing, pointing to a role of AtPARP3 in ROS-induced DNA damage responses during seed storage and germination [AtPARP3 in other plant species, such as Populus trichocarpa, Physcomitrella patens, Oryza sativa, Brachypodium distachyon, Sorghum bicolor, Zea mays, and Hordeum vulgare [In adult esponses . In contesponses ,109. A smination . A simil in rice . In addi in rice ,127. Henmination ,128. Dat vulgare ,114,125.+ in the salvage pathway [Arabidopsis, the expression pattern of AtPARP3 correlates with that of Nicotinamidase 2 (NIC2) [nic2 mutant seeds was hypersensitive to MMS, potentially due to reduced levels of poly(ADP-ribosyl)ation, which are, in turn, likely to be due to a reduced nicotinamide degradation [The activity of PARPs produces the feedback inhibitor nicotinamide as byproduct . Nicotin pathway . In Arab2 (NIC2) . Germinaradation ,127. On radation . This isHordeum vulgare, expression of HvPARP3 in young seedling roots was enhanced by the DNA DSB-inducing agent bleomycin [parp3 mutant seeds in the presence of DNA DSB-inducing agents, crossing of parp3 mutants with ku70 and ku80 mutants may provide evidence whether AtPARP3 acts in NHEJ like its mammalian counterpart. Since direct evidence of poly(ADP-ribosyl)ation activity of AtPARP3 is lacking so far, PARP activity needs to be determined in parp3 mutant seeds. Aberrant poly(ADP-ribose) levels will indicate whether AtPARP3 is capable of poly(ADP-ribosyl)ation. However, a mono(ADP-ribosyl)ation activity by this enzyme, similar to its human counterpart, is also conceivable. Since AtPARP3 shows structural homologies to AtPARP1 and human PARP3 , similarleomycin , supportparp mutant plants, Arabidopsis parg1 mutants exhibited enhanced sensitivity to mitomycin C and bleomycin [parg1 mutations induced more severe plant damage than the lack of AtPARPs [Similar to leomycin . Mutant leomycin ,130. Not AtPARPs . This wa AtPARPs .SMC6A, SMC6B, RAD17, RAD51, RAD54, REV7) and NHEJ components  was found in parg1 mutants [RAD51 and SWI expression induced by the bacterial elicitor flg22 were disrupted in parg1 mutants [AtPARG1 expression was attenuated in atm and atr mutant plants and vice versa [The mechanistic role of PARGs in DNA damage responses of plants still has to be elucidated. Enhanced expression of HR components ating activity on chromosomal proteins. AtPARP1 and AtPARP2 associate with chromosomes in dividing cells via their N-terminal domains . TherebyAtPARP1 and AtPARP2, but not AtPARP3, is increased in response to telomerase dysfunction [Arabidopsis PARP is involved in telomere end protection and telomere length protection in seedlings and flowers [Expression of function ,134. How flowers . In cont flowers . This ap2O2-induced PCD in cultured tobacco and soybean cells, whereby the PARP inhibitor-mediated protection from H2O2-induced PCD was most effective during the initial phase of H2O2 treatment [+ levels in the soybean cells indicated the onset of PARP activity. Interestingly, overexpression of AtPARP2 in soybean cell culture resulted in reduced cell death at low concentrations of H2O2 (mild oxidative stress), but a dramatically increased cell death at high H2O2 concentrations (severe oxidative stress). In addition, AtPARP2 expression reduced the amount of nicked DNA under both mild and severe oxidative stress [Mammalian PARP proteins are regulators of various facets of cell death see . Comparareatment ,136. At e stress . AdditioAtPARP1 and AtPARP2 expression and their activity increased in Arabidopsis cell cultures during the exponential growth phase [parp1, parp2, and parp3 mutant plants. Under non-stressed conditions, parp3 plants germinated faster than the wild type, while parp1 and parp2 exhibited slower and partially reduced germination rates [Apart from DNA damage and PCD, PARP proteins and poly(ADP-ribosyl)ation have been proposed to play an important role in plant development . For exath phase . This inth phase . Hence, on rates . Arabidopsis growth under non-stressed conditions [parp1 parp2 double mutant plants led to the formation of a larger root system compared to the wild type [Arabidopsis PARP genes, including all double mutant combinations and a parp1 parp2 parp3 triple mutant, did not display obvious developmental alterations under non-stress growth conditions [In addition to germination, plant growth regulation appears to involve poly(ADP-ribosyl)ation, since the PARP inhibitor 3MB has been shown to improve nditions ,139. Enhnditions ,131,139.nditions ,131,140,nditions . Similarild type , but thinditions . This isnditions ,108,116.AtPARP and AtPARG genes was altered in response to abiotic stresses [PARP1 or PARP2 in oilseed rape and Arabidopsis by PARP hairpin constructs enhances the tolerance to desiccation, short-term paraquat treatment, and high light, associated with a reduced PARP activity under stress [PARP knockdown lines. Additional explanations were provided by a transcriptomic study on plants with reduced AtPARP1 expression [−2 sec−1), AtPARP1 knockdown led to an attenuated expression of temperature-responsive and oxidative stress-dependent genes. Furthermore, genes involved in cellular transport and energy metabolism were repressed, again supporting the hypothesis that reduced PARP activity enhanced stress tolerance by reducing oxidative stress and preserving energy homeostasis. In contrast, genes responsive to abscisic acid (ABA), dehydration, and cold were hyper-induced by AtPARP1 knockdown under high light stress [AtPARP1 expression. These findings pointed to a role of AtPARP1 as a negative transcriptional regulator of plant stress responses in an ABA-dependent way. This provoked an additional hypothesis to explain the enhanced abiotic stress tolerance by reduced PARP activity, linking the increased NAD+ levels to the increased ABA levels and the increased expression of ABA-responsive genes via cyclic ADP-ribose (cADPR) [+ as a substrate, and it is involved in ABA-dependent stress signaling, as well as in the regulation of the circadian clock [2+ from internal stores, which induces ABA production and hence ABA-responsive gene expression. It was hypothesized that the preservation of the NAD+ pool by a reduction in AtPARP1 expression promotes cADPR synthesis, thereby conferring enhanced stress tolerance. Albeit the synthesis of cADPR, its activity as Ca2+-releasing second messenger, and its involvement in ABA and nitric oxide signaling have individually been demonstrated in plants [2+ channels  are present in higher plants [PARP proteins of plants have been associated with responses to abiotic stress. In some studies, the expression of stresses ,104, albstresses ,146,147.r stress . Accordir stress . Hence, pression . Under “t stress . Simulta (cADPR) . This moan clock ,149,150.n plants ,153,154,r plants . The tesArabidopsis single, double, and triple knockout mutants for all three AtPARP genes was unchanged from the wild type when exposed to desiccation, salt, osmotic, or oxidative stress [quill shows similar root growth as the wild type on 0.5% sucrose, but dramatically reduced root growth on 4.5% sucrose medium. Under these conditions, root growth of wild type plants is even pronounced [petit1 mutant shows reduced hypocotyl elongation on sucrose-containing medium, but not on sucrose-free medium [elf3 shows rhythmic leaf movement in the dark and under several light/dark regimes, but not under constant light [vad1 mutants show hypersensitive response-induced lesions under high, but not under low, light intensities [The notion of plant PARPs as important negative factors of abiotic stress tolerance has been challenged by a recently reported study, wherein growth of e stress . These oe stress . Factorse stress . Accordie stress . For insonounced . Similare medium . The phont light . Not onlensities . In contensities . These eArabidopsis plants grown in unstressed conditions [+ content was increased under both unstressed and oxidative stress conditions [Brassica napus hypocotyl explants to oxidative stress elicited by acetyl salicylic acid [Lemna minor facing osmotic stress by polyethylene glycol treatment (−0.3 MPa) and tolerance of an Arabidopsis cell culture to H2O2 [Compared to genetic PARP inhibition, pharmacological PARP inhibition has been widely used as a tool to elucidate the role of PARP proteins in plant stress tolerance ,139,163.nditions . Notablynditions ,139. Thenditions . Reductinditions . Additiolic acid . In anot to H2O2 , other a to H2O2 . This diPseudomonas bacteria and the N-terminal 18 amino acids of EF-Tu (elf18) from Escherichia coli are such PAMPs. They elicit immune responses such as oxidative burst, elevation of cytosolic free Ca2+, cell wall reinforcements by callose and lignin, and transcriptional induction of defense genes [Arabidopsis seedlings [Pathogen-associated molecular patterns (PAMPs) are structural or functional units of a microbe that are recognized by the plant immune system and elicit defense responses. The N-terminally conserved 22 amino acids of flagellin (flg22) from se genes ,165,166.eedlings ,130,140,eedlings . This efeedlings ,130. In eedlings ,102, whiA number of other pharmacological studies have assigned PARPs a role as regulators of pathogen responses. For example, the PARP inhibitor 3MB, which is structurally very similar to 3AB, has been shown to negatively influence the phenylpropanoid pathway ,139. SimAtPARP1 or AtPARP2 in T-DNA single knockout lines did not alter flg22-induced callose deposition, whereas in two studies parp1 parp2 double mutant lines exhibited enhanced or reduced callose deposition, depending on the plant age and/or flg22 concentration applied [parp2 mutant plants and parp1 parp2 double mutant plants displayed enhanced sensitivity towards the Pst strain DC3000 [+ levels and increased leaf poly(ADP-ribose) content [parp1 parp2 parp3 triple knockout seedlings [parp mutant phenotypes and of off-target effects of PARP inhibitors, which remain to be tested experimentally.Contrary to pharmacological PARP inhibition by 3AB and 6-(5H)-phenanthridinone, genetic abolishment of  applied ,168: The applied , while in DC3000 ,101. Thi content . Taken teedlings ,102. In Pst DC3000, P. syringae pv. maculicola, non-pathogenic Pst DC3000 hrcC (a type III secretion mutant of Pst DC3000), and non-adaptive pathogen P. syringae pv. phaseolicola [ddl mutants showed reduced callose deposition in response to flg22 and Pst DC3000 hrcC. In contrast to pharmacological PARP inhibition, early PAMP-induced gene expression was reduced in parp1 parp2 mutants, but not in ddl [parp1 parp2 and ddl [parp1 parp2 and ddl further indicated an interaction of these proteins in response to PAMPs. In fact, an interaction of AtPARP2 and DDL was confirmed by immunoprecipitation and bimolecular fluorescence complementation assays, and found to be enhanced by flg22. The direct interaction of both proteins was markedly stronger upon poly(ADP-ribosyl)ation. In addition to AtPARP2, AtPARP1 was also shown to poly(ADP-ribosyl)ate DDL, but to a lesser extent than AtPARP2. A DDL protein lacking its poly(ADP-ribosyl)ation sites was unable to complement the susceptibility to PAMP treatment, indicating that poly(ADP-ribosyl)ation of DDL is essential for proper plant immune response. As DDL enhances late PAMP-induced gene expression, and as it was suggested to interact with histone acetyltransferases in Arabidopsis, Feng and colleagues concluded that DDL is involved in poly(ADP-ribosyl)ation-mediated chromatin remodeling to allow access to target gene promoters during plant immunity [A new actor in PARP-mediated plant immunity has been identified recently. Mutant plants lacking the AtPARP2-poly(ADP-ribosyl)ated protein DWADLE (DDL) exhibited an exacerbated sensitivity to eolicola . Similart in ddl ,168; latparg mutants should also display altered responses to biotic attack. Accordingly, parg1 but not parg2 mutants displayed a more severe growth inhibition upon elf18 treatment accompanied by an enhanced pigment accumulation [parg1 plants also displayed enhanced flg22-induced callose deposition and increased expression of flg22-regulated genes [parp mutant plants and pharmacological PARP inhibition, the early PAMP-induced ROS production was not altered in the parg1 mutant plants. Nevertheless, this mutant displayed transcriptional changes in defense gene expression [B. cinerea infection was accelerated in both parg1 and parg2 mutant plants [AtPARG2 expression was up-regulated in response to Pst and Botrytis cinerea infection and flg22 treatment, while AtPARG1 was only transiently induced by treatment with flg22 and elf18 [Since PARGs antagonize PARP action, mulation . Mature ed genes . Similarpression . These cpression . Apart ft plants . Hence, nd elf18 ,130,140.Arabidopsis, the family comprises the proteins Radical-induced Cell Death1 (RCD1) and its homologues SRO1 through SRO5 [In addition to the canonical PARP proteins, members of the SRO (Similar to RCD One) family possess a catalytic PARP domain, albeit with an unusual catalytic triad motif ,170. Theugh SRO5 . In contugh SRO5 ,174. In ugh SRO5 .Arabidopsis and oxidative stress regulators in yeast [Arabidopsis rcd1 mutant plants were hypersensitive to ozone treatment and the resulting apoplastically-produced ROS [rcd1 plants are resistant to ROS formed in the chloroplasts upon paraquat treatment [RCD1 is expressed ubiquitously and constitutively in Arabidopsis plants [Hyaloperonospora arabidopsis, and binding of this effector suppresses the activation of salicylic acid-induced defense genes and alters light responses [Rcd1 mutant plants show severe developmental defects, such as stunted growth, altered rosette and leaf morphology, early flowering time, and a high number of differentially regulated genes [+/H+ antiporter SOS1 and in particular with transcription factors from various families, such as AP2/ERF, NAC , MYB, and basic helix–loop–helix [RCD1 is the first recognized member of this protein family. It was initially identified during screenings for ozone sensitivity in in yeast ,176. Accuced ROS ,176. In reatment ,177. RCDs plants ,178. It s plants ,180, buts plants ,189,190.esponses . RCD1 isesponses . Rcd1 mued genes ,174,178.op–helix . The mosop–helix ,174,192,op–helix . This inop–helix ,195. Theop–helix . In DREBop–helix . Insteadop–helix . Accordiop–helix . In summSRO1 are generally lower than those of RCD1 [rcd1 mutant plants, sro1 plants did not exhibit sensitivity to ozone and salt stress, and grew normally under unstressed conditions [The PARP domain protein SRO1 shares 76% similarity with RCD1. Both proteins were identified to be paralogs likely arising from a gene duplication . They bo of RCD1 . In contnditions ,178. Simnditions . Double nditions ,178,198.nditions .RCD1 and SRO1, which show hardly any changes in their expression upon stress, SRO5 transcript levels changed upon salinity, ozone, light, wounding, anoxia, and bacterial elicitors [SRO5 transcripts form siRNAs with a gene overlapping in antisense orientation, P5CDH (1-pyrroline-5-carboxylate dehydrogenase), thus regulating it at the post-transcriptional level. Surprisingly, expression of the P5CDH gene was not enhanced in sro5 mutant plants [SRO5 and P5CDH did not overlap in Arabidopsis lyrata, grapevine, and poplar [P5CDH is not a primary function of the SRO5 gene [SRO5, SRO2 and SRO3 showed changes in their transcript levels in response to light, salt and ozone [Another member of the SRO family is SRO5. In contrast to licitors ,199. Addlicitors : upon sat plants ,199. Apad poplar . It was RO5 gene ,199. SRORO5 gene . SimilarRO5 gene , providind ozone .Arabidopsis RCD1 and SRO1, this rice protein interacts with DREB and NAC transcription factors [ZmSRO genes was differentially affected by stress and hormone treatments [The central position of the SRO family in signaling and stress responses also holds true for monocots. The modulation of ROS homeostasis and a positive role in abiotic stress resistance have been demonstrated for a wheat homolog of RCD1/SRO1, Ta-SRO1 . An SRO  factors . Interac factors . Another factors . Co-expr factors . Recentl factors ,204. Theeatments ,204.Arabidopsis and monocotyledonous crop species, members of the family have recently been described in other dicotyledonous species. The tomato protein Sl-SROl1, most similar to AtSRO5, improved salt tolerance when expressed in Arabidopsis [Arabidopsis ortholog [Even though research on SRO proteins has mostly focused on bidopsis , and theortholog .PARP knockout [parp triple mutant [In addition to their function in DNA damage responses see , plant Pknockout ,139,163.knockout . In Arabe mutant , which me mutant , wherease mutant . NeverthThe notion that PARP inhibitors have off-target effects is further supported by a recent transcriptomic study in which, under standard growth conditions, a treatment with the established PARP inhibitors 3AB and 3MB altered the expression of 228 and 3935 genes, respectively . This diDue to the potential off-target effects, the use of pharmacological PARP inhibitors to infer PARP function in plants should be reconsidered. As a first step to identify additional targets of those drugs, pull-down experiments using the pharmacological “PARP inhibitors” as bait may be a suitable approach.parp mutants are of a conditional nature. This now calls for an extensive systematic analysis of growth conditions and plant developmental stages to identify the circumstances under which PARP modification causes an alteration of stress responses. In their natural habitat, plants are under the constant threat of biotic and abiotic stressors. Global warming is proposed to increase these threats, endangering future food security. The inhibition of PARPs by genetic or pharmacological means has been suggested as a promising approach to sustain crop yields and hence food security, since PARP inhibition has been found to improve plant performance under abiotic stress. However, the positive effects of PARP inhibition are not as robust as initially suggested, since it has become apparent that the stress-related phenotypes of PARPs/SROs or pharmacologically-altered PARP activity.The currently available data therefore suggest that inhibition of canonical PARPs may not be a way forward to stabilize food security. Moreover, PARP inhibition has been shown to exert negative effects on pathogen resistance mechanisms. However, simultaneous or sequential occurrence of abiotic and biotic stress elicits tailored physiological and transcriptional responses that differ from those to single stressors. Accordingly, abiotic and biotic stressors have been reported numerously to have either additive effects, i.e., increasing plant stress level and symptoms, or antagonizing effects, i.e., increasing resistance to one of the stressors ,208,209.In this respect, it is an important future task to experimentally determine the potential additional targets of PARP inhibitors, as this may allow the design of specific inhibitors targeting those proteins. They may be of use in future crop improvement strategies, as the beneficial activities of canonical PARPs would not be affected. Finally, to better understand the mechanistic role of PARP domain proteins in stress responses, the identity of poly(ADP-ribosyl)ated proteins and poly(ADP-ribose)-binding proteins needs to be elucidated.


Selenium, through incorporation into selenoproteins, is one of the key elements of the antioxidant system. Over the past few years there has been increased interest in exploring those molecular mechanisms in chicken, responsible for the development of this protection system. In more detail, Cd/Pb poisoning and heat stress increase oxidation, mRNA levels of inflammatory proteins, and apoptotic proteins. Selenium seems to enhance the antioxidant status and alleviates these effects via upregulation of antioxidant proteins and other molecular effects. In this review, we analyze avian transcriptome key elements with particular emphasis on interactions with heavy metals and on relation to heat stress. Selenium (Se) is characterized as a vital nutrient for animals and humans ,2,3. In Bcl-2, p53 and other genes, stimulating the release of cytochrome c (Cyt-c) and thereafter apoptosis [Hypophthalmichthys molitrix) and triggered kidney damage [Cadmium (Cd) is a heavy metal and extremely toxic. It is accumulated into birds’ organs mainly through the feed and on elevated concentrations can cause acute or chronic poisoning . One of poptosis . As in tpoptosis ,23. Furtpoptosis ,25. Alsopoptosis . It has y damage ,28. HSP27, HSP40, HSP60, HSP70, and HSP90 in the chicken testes. However, mRNA expression of HSP40 was the lowest in the Pb group and it was found about 24 times higher compared to the control group. These outcomes indicate that Pb toxicity results in higher mRNA expressions of HSPs [Lead (Pb) is another extremely toxic heavy metal that is broadly distributed in nature due to human activities. Lead can seep into the environment via various ways, including sewage discharges and burning of fossil fuels . It has  of HSPs . Heavy metals are extremely poisonous for avian species. They cause dysfunctions in many organs and alter expression levels of many inflammation factors and antioxidative agents such as selenoproteins. In the later part of this review, we discuss in detail the effects of Cd/Pb toxicity on avian transcriptome and the benefit of Se supplementation.iNOS mRNA levels, Cd accumulation and NO production. Furthermore, Cd induced brain damage by adjusting iNOS–NO system changes [The predominant mediators of inflammation, cytokines, play a critical role in the inflammatory response induced by Cd exposure and other various environmental challenges in living organisms. Some studies have demonstrated that immune cells inflammatory response is closely related to the expression of inflammatory cytokines. TNF-α is the most important cytokine, activating neutrophils and lymphocytes, promoting the synthesis and release of other cytokines . On the  changes .IL-1B while decreased IL-17, IL-10, IL-4, IL-2, and IFN-γ in chicken splenic lymphocytes indicating an impact on immune responses. Supplementation with Se decreased Cd toxicity and in addition the mRNA expression levels of IL-17, IL-10, IL-2, IL-4, and IFN-γ were higher than in the Cd alone treated group. However, the mRNA expression levels were not as high as in the Se alone treated group and the control group. Expression levels of mRNA of IL-2 were also higher in Cd and Se treated group than in Cd group. Additionally, in respect to the control group, the mRNA levels of IL-10 and IL-4 in chicken splenic lymphocytes were decreased dramatically due to Cd toxicity [It has been reported that Cd stimulation causes the expression of ICAM-1 via NF-κB activation in cerebrovascular endothelial cells similar to findings by Liu et al. . Moreovetoxicity .IL-10 and IL-1B. At gene level, the altered gene expression regulation of cytokines induced the raise of IL-4 and suppression of IFN-γ production. Cadmium could influence the immune inflammation of neutrophils by modifying the regulation of cytokine expression as it turned out via the suppression of IL-17 production, the raise of IL-4 release and the production of proinflammatory cytokines IL-1B, TNR-α, IFN-γ, and IL-10. Also, Cd moderately induced the pro-inflammatory cytokines NF-κB, iNOS, TNF-α, COX-2, and PGE2. Furthermore, inflammation caused by Cd raised iNOS activity and NO production. Analogous results were demonstrated in the levels of NF-κB protein expression [Moreover, Cd exposure could trigger immune cells to raise the mRNA expression of pression ,46.GRP78, and caspase-3 increased significantly while levels of CaM and Bcl-xL decreased in the peripheral blood neutrophils of chicken in the Cd treatment group [The key step for enabling downstream caspases, a family of protease enzymes playing essential roles in programmed cell death and inflammation, is the activation of Bak, a member of the proapoptotic Bcl-2 family, at the mitochondria. This has a crucial role in the regulation of apoptosis under chronic endoplasmatic reticulum stress (ERS). The role of ERS in inflammation and stress is not unilateral, ERS can be triggered by a variety of inflammatory factors, and many inflammatory diseases are associated with ERS. Similarly to previous reports on Cd toxicity and ERS, Chen et al. showed that Cd induces high expression of TNF-α, IL-1b, IL-4, and IL-10 in peripheral blood neutrophils of broiler, acting as strong inducer of ERS and activating ER pathways, one of which is ATF6 cleavage . When Cdnt group .IL-1β, TNF-α, COX-2, PTGES, and NF-κB mRNA levels while similarly, in hens serum, TNF-α, and IL-1b were significantly increased [Cyt-c, caspase-9, Bax, p53, and protein levels of caspase-3, Bax, and Cyt-c in liver of chicken. However, Cd toxicity reduced Bcl-2 protein and mRNA levels. These findings pointed that Cd induced apoptosis in chicken hepatocytes by the NO-mediated mitochondrial-dependent pathway and that Cd-triggered apoptosis was mediated by the pro-apoptotic genes Bax, p53, and Bcl-2 [On the other hand, in hens liver, Cd toxicity caused significant increase of ncreased . Recentlncreased . Moreovend Bcl-2 . Bak activation and triggers BNIP3-dependent autophagy on chicken neutrophils. Some ways on how Se supplementation may alleviate Cd toxicity are proposed.Messenger-RNA expression of inflammatory cytokines plays a crucial role in inflammatory response. Under inflammatory conditions due to Cd exposure, NO levels and inflammatory cytokines are increased in avian tissues. Also, Cd toxicity induces strongly ERS. In addition, Cd toxicity induces apoptosis on chicken liver and neutrophils via COX-2, NF-κB, PTGES, and TNF-α mRNA levels caused by Cd in chicken kidneys. The mRNA levels of NF-κB and TNF-α slightly increased in Se/Cd treated group in relation to control group but PTGES and COX-2 mRNA levels were not influenced [Atg5, LC3-I, LC3-II, Beclin 1, dynein) caused by Cd treatment [There is little information about possible interactions of Se and Cd in mRNA expression of inflammation factors and selenoprotein genes. A study on Se/Cd treated chicks showed that Se co-administration with Cd alleviated the increase of fluenced . Cadmiumreatment .Bak, p53, caspase-3, caspase-9, and Cyt-c increased significantly, and Bcl-2, Bcl-xl, and CaM decreased in chicken splenic lymphocytes of Cd treatment groups. Furthermore, Amantana et al. showed that Cd exposure decreased induction of the promoter of selenoprotein W in rat myoblast and glial cells, which indicates that Cd targets some selenoproteins [2+ leakage in muscles [GPX1 and TRXR1 were obviously lower in the Cd group compared with other groups. However, the Cd/Se co-treatment significantly attenuated this decrease. Selenium supplementation alone with Cd treatment significantly increased the mRNA of GPX1 and TRXR1, similar to the immunoblotting results of GPX1 and TRXR1 [Also apoptosis and the mRNA level of proteins . Cadmiumproteins . Selenop muscles . As a re muscles . On the nd TRXR1 .SPS2, Sepp1, Sepx1, DIO3, DIO2, DIO1, GPX4, GPX3, GPX2, GPX1, TXNRD3, TXNRD2, and TXNRD1) [DIO3, GPX3, and GPX2 levels, but not in the mRNA expression levels of another 14 selenoprotein genes . In the group with Se/Cd treatment, the mRNA expression levels of selenoprotein W, selenoprotein U, selenoprotein T, GPX3, and GPX2 alleviated, while the amount of alleviation was minor than that in the group with Cd treatment. The expression levels of selenoprotein N, selenoprotein K, selenoprotein S, selenoprotein O, selenoprotein M, selenoprotein I, selenoprotein H, selenoprotein 15, selenoprotein Pb, Sepx1, Sepp1, SPS2, DIO3, DIO2, DIO1, TXNRD3, TXNRD2, TXNRD1, GPX4, and GPX1 were not affected [In a study examining Cd exposure and chicken’s kidney selenotranscritome regulation, there was a significant difference between the control group and Se-treated group in the mRNA levels of all 25 selenoprotein genes  . Among taffected ,55. Addiaffected ,56.GPX4 and selenoprotein P [Bax and Cyt-c. Moreover, mRNA levels of Bcl-2 raised when concurrently supplemented Se and Cd in chicken nutrition [Apart from the studies mentioned above, Se protection mechanism against Cd toxicity is based on antioxidant proteins. Also, in another study, Se ameliorated Cd-induced oxidative stress through regulation of mRNA levels of rotein P . Howeverutrition .Under chemical or noxious physical stimuli, one of the most important indicators of tissue damage is inflammation. The NF-κB signaling pathway has a significant role in inflammation regulation via the transcription of diverse target genes, including iNOS, COX-2, and TNF-α. Regarding COX-2 and iNOS, they are significant enzymes that mediate processes of inflammation . iNOS inATF4, PERK, caspase-3, caspase-12, eIF2α, and CHOP in chicken testes [Selenium could as well antagonize Pb-induced damage on inflammatory cytokines gene expression in chickens’ peripheral blood lymphocytes . Chickenn testes . This inATF4, and GRP78, and alleviation occurs via Se supplementation in chicken kidneys [Wang et al. showed that Se supplementation alleviates accumulation of Pb in testes of chicken . Additio kidneys .CHOP, eIF2α, and PERK mRNA expression and these effects were alleviated by Se in chicken testes [NF-κB, COX-2 and TNF-α expression in chicken neutrophils [In the same way, Pb-induced increase of n testes . These rn testes . Futhermtrophils . NF-κB, TNF-α, COX-2, PTGEs, iNOS, HSP27, HSP40, HSP60, HSP70, and HSP90, the NO content, and the iNOS activity in chicken liver. Also in this case, Se supplementation alleviated those changes [iNOS, NF-κB, COX-2, and TNF-α, NO content and Pb deposition was ameliorated via Se supplementation in the testes of chicken [Lead, in addition, induces the mRNA expression of  changes . Likewis chicken . In the  chicken .IL-4, IL-6, IL-12β, and IL-17) mRNA levels increase that were caused due to Pb poisoning [TGF-β4, IL-4, IL-8, IL-10, IL-12, IL-1β, IL-1R and reduced that of IFN-γ and IL-2. Neutrophil injury and impair immune function in chicken could be induced by Pb poisoning [TGF-β4, IL-12, IL-10, IL-8, IL-4, IL-1R, IL-1β, HSP90, HSP70, HSP60, HSP40, and HSP27. In contrast, HSP70, HSP60, and HSP40 were highly related to IL-1β [GPX4, and in embryonic neurocytes Pb induced the mRNA decrease of selenoprotein U. Furthermore, multivariate correlation analysis demonstrated positive correlations between twenty-five selenoproteins; four apoptosis-related genes ; and between Bcl-2 and the selenoproteins in the embryonic neurocytes and chicks brain tissues [In chicken neutrophils the mRNA expression levels of 23 selenoproteins (except of GPX3) and TNF-α, NF-κB, and iNOS were dramatically raised during Pb poisoning. However, Se supplementation alleviated this trend of inflammation factors, increased the mRNA levels of selenoproteins and decreased serum Pb content. Li et al. found positive correlations among inflammatory factors, besides COX-2. COX-2 might have played a principal function in Se antagonism against Pb . Jiao etoisoning . In accooisoning . There wto IL-1β . Zhu et to IL-1β  showed t tissues . PTGEs, COX-2, TNF-α, and NF-κB were decreased with implementation of Se supplementary diet compared with the Pb diet group. The results indicated that Se antagonized Pb induced inflammation [SPS2, Sepx1, selenoprotein 15, selenoprotein M, Sepw1, TXNRD1, TXNRD3, TXNRD3, DIO1, DIO3, Sepn1, selenoprotein K, selenoprotein S, selenoprotein T, selenoprotein H, selenoprotein I, selenoprotein U, selenoprotein Pb, Sepp1, selenoprotein O, GPX2, GPX3, and GPX4 [NF-κB, TNF-α, COX-2, and iNOS in chickens’ peripheral blood lymphocytes were significantly higher than in the control [COX-2, TNF-α, iNOS, HO-1, and NF-κB [GPX4, GPX2, GPX1, DIO1, DIO2, TXNRD2, TXNRD3, Sepx1, selenoprotein O, selenoprotein K, selenoprotein M, selenoprotein T, selenoprotein W, Sepn1, selenoprotein 15, selenoprotein I, and selenoprotein U triggered by Pb exposure in the meniscus cartilage. Additionally, in the sword cartilage, Se alleviated the downtrend of mRNA expression of DIO2, DIO3, TXNRD1, TXNRD2, selenoprotein K, selenoprotein W, selenoprotein I, selenoprotein H, SPS2, Sepx1, selenoprotein 15, selenoprotein O, selenoprotein M, selenoprotein P, selenoprotein T, selenoprotein n1, GPX2, GPX3, and GPX4 induced by Pb toxicity [In chicken hearts, mRNA expression levels of ammation . Also, Sand GPX4 . Similar control . In corrnd NF-κB . Gao et nd NF-κB  , illusttoxicity . TXNRD1, TXNRD2, and TXNRD3, selenoprotein H, selenoprotein I, selenoprotein K, selenoprotein T, selenoprotein M, selenoprotein W, selenoprotein Pb, selenoprotein S, selenoprotein O, selenoprotein U, DIO1, DIO2, DIO3, selenoprotein 15, Sepn1, Sepp1, Sepx1, SPS2, GPX1, GPX2, GPX3, and GPX4) in chicken testes showed highest expression levels in the Se supplemented groups than in the Pb exposed chicken groups indicating an increase of the antioxidative potential due to Se supplementation. Also, there were positive correlations between the selenoproteins gene expression and the expression of five HSPs  [Finally, 25 selenoprotein genes (d HSP70) . From the aforementioned, it can be concluded that Se supplementation can alleviate the toxic effects of Pb, by increasing the antioxidative potential in several chicken tissues via upregulation of many antioxidant proteins. A summary of selected studies in chicken describing the effects of heavy metals on various factors, HSP, and selenoproteins is shown in Regarding heat stress (HS), the poultry industry is sensitive to economic losses due to poor thermotolerance of broiler chickens ,78. St-PHeat stress causes reduction of body weight gain and feed consumption , and is Heat stress has been shown to lead to diminished growth rate in various studies . AdomakoFurthermore, meat quality was degraded under HS conditions. Poultry have increased contents of polyunsaturated fatty acids in muscles and are extremely sensitive to oxidative stress when exposed to high temperatures ,102. PosGRP94 and GRP78 mRNA levels considerable raised which clearly indicates that ER stress occurs by HS. Also, multiple molecular pathways such as ATF6, PERK, and IRE1 have interrelation with stress in ER. During ER stress, the expression of the above genes were elevated [Slawinska et al.  showed televated . In the 2+ [Heat stress alters the mRNA expression of oxidants thereby increasing cellular ROS. The NOX family is consisted of seven members  and SOD3 (extracellular isoform) contain Cu and Zn, whereas SOD2, the mitochondrial isoform, has Mn in its reactive site . In anotlocation . Notwithlocation  superoxilocation  results,2O2 is converted to water and oxygen, and through GPX, H2O2 is converted to water in a reaction, oxidizing GSH to its disulfide form (GSSG). Glutathione is regenerated from GSSG by GR. Data concerning the regulation of CAT, GPX, NADPH, and GR in both acute and chronic HS is insufficient. The GPX, CAT, and NADPH genes were negatively regulated at 1 day post-HS, presumably as a result of H2O2 raise. It has been demonstrated that exhibition to ROS negatively regulated CAT expression through hypermethylation of a CpG island in CAT promoter [2O2 due to HS may have caused the negative regulation of GPX and CAT. This may be true not only at gene level, since in case of GPX, post-translational modifications have been reported irrespective of changes at gene expression levels [Differently, through the antioxidant enzyme catalase (CAT), Hpromoter ,125. Τhen levels .Nrf2 gene was slightly negatively regulated at 1 day post-HS, but not at 12 days post-HS.Niu et al.  showed tThe induction of NADPH and GST by electrophiles and antioxidants has been shown to be mediated by the activation of Nrf2 in human . It shouSOD2, GPX2, NOX4, and CAT expression were significantly lower in the TM groups in two chicken breeds (Hubbard and Cobb) [NOX4 expression in the TM groups alleviates oxidative stress by decreasing NOX-induced ROS. Additionally, AvUcp expression levels in the Hubbard and Cobb TM groups generally increased after exposure to acute heat stress (AHS) compared to controls. These results indicate that TM through raising AvUcp mRNA levels has a positive effect on ROS reduction. In relation with the above results, TM treatment has a role in decreasing heat-induced oxidative stress, the latter of which can be ascertained by the reduction and elevation of NOX4 and AvUcp mRNA levels, respectively. Lastly, they showed that TM directs thermotolerance acquisition in broiler chicken and indicated considerable differences among breeds [Al-Zghoul et al. in their experiment on thermal manipulated (TM) chicks illustrated that levels of nd Cobb) . This deg breeds .Moreover, the relative mRNAs expression of HSP  in the heart of broiler chickens were significantly elevated after exposure to HS for 2 h and then declined rapidly with further exposure. In addition, the up-regulation of these stress proteins in heart act as important biomarkers and protective proteins at the start of HS . A summaSeveral nutritional approaches, such as supplementation of diets with phytochemicals, have been used in attempts to attenuate the negative effects of HS . VitaminGPX1, GPX4, and selenoprotein P mRNA levels when broilers were fed Se and Se+Vit E supplemented diets. However, no effect on these indices was recorded in broilers given the Vit E supplemented diet.Furthermore, Vit E and Se combined supplementation proved to be the most effective inhibitor of lipid peroxidation. Dietary Vit E and Se supplementation led to significant increases in SOD and CAT levels in breast muscle of heat-stressed broilers. Selenium alongside with Vit E had a synergistic effect on SOD, GPX, and CAT activity. However, Shahnawaz Kumbhar showed that enzyme activity of GPX remained depressed in case of dietary Vit E . FurtherSelenium performs its biological functions mainly through selenoproteins, as Se is mainly incorporated in selenoproteins’ active sites . SelenopThus, Nano-Se supplementation has been proposed for reduction of HS effects in broilers. In a study on the effects of dietary Nano-Se supplementation at 0.6 and 1.2 mg/kg of diet on growth performance, serum biochemical parameters, immune response, antioxidant capacity, and jejunal morphology of 29-d-old male broilers subjected to HS at 37 ± 1 °C for 14 d, it has been shown that heat-stressed broilers had lower FI and BMG, but higher FCR than those kept in thermoneutral condition. According to Safdari-Rostamabad’s  study ouHu et al. , compareHSP70 mRNA levels in comparison to control [In another study, when broilers were supplemented with Se enriched prebiotics (SP), a significant downregulation was observed in the expression of the HSPs  heat stress biomarkers in the breast muscles of each experimental group compared with the control group. The SP group had a profound effect on decreasing the  control .The field of selenoprotein transcriptome in chicken and its interactions with heavy metals has recently been attracting more and more research interest . The seaRegarding research on selenoprotein transcriptome in chicken and its adaptation to HS and Se deficiency, the number of articles has also an increasing trend . The seaIt can be concluded that the toxic effects of Cd and Pb and the harmful effects caused by heat stress in chickens are alleviated via supplementation of Se. Studies highlight selenium’s role as antioxidant and modulator for the enzymatic and non-enzymatic antioxidant defense factors such as GSH, GPx, and TrxR in order to modulate the toxic effects of heavy metals in chicken. Further, Se alleviates the excess of mRNA expression levels of apoptotic factors, immune proteins, and heat stress proteins caused by heavy metals. In addition, over heat stress conditions, Se through upregulation of GPxs and other selenoproteins, eliminates heat stress proteins mRNA levels in many chicken tissues and reduces mRNA increase of inflammatory factors and other chicken immune responses.


Garcinia species. Recently, we reported MF as a novel inhibitor of ATPase and microtubules-gliding activities of the kinesin spindle protein (Eg5) in vitro. Herein, we provide dynamical insights into the inhibitory mechanisms of MF against Eg5, which involves binding of the inhibitor to the loop5/α2/α3 allosteric pocket. Molecular dynamics simulations were carried out for 100 ns on eight complexes: Eg5-Adenosine diphosphate (Eg5-ADP), Eg5-ADP-S-trityl-l-cysteine (Eg5-ADP-STLC), Eg5-ADP-ispinesib, Eg5-ADP-MF, Eg5-Adenosine triphosphate (Eg5-ATP), Eg5-ATP-STLC, Eg5-ATP-ispinesib, and Eg5-ATP-MF complexes. Structural and energetic analyses were done using Umbrella sampling, Molecular Mechanics Poisson–Boltzmann Surface Area (MM/PBSA) method, GROMACS analysis toolkit, and virtual molecular dynamics (VMD) utilities. The results were compared with those of the known Eg5 inhibitors; ispinesib, and STLC. Our data strongly support a stable Eg5-MF complex, with significantly low binding energy and reduced flexibility of Eg5 in some regions, including loop5 and switch I. Furthermore, the loop5 Trp127 was trapped in a downward position to keep the allosteric pocket of Eg5 in the so-called “closed conformation”, comparable to observations for STLC. Altered structural conformations were also visible within various regions of Eg5, including switch I, switch II, α2/α3 helices, and the tubulin-binding region, indicating that MF might induce modifications in the Eg5 structure to compromise its ATP/ADP binding and conversion process as well as its interaction with microtubules. The described mechanisms are crucial for understanding Eg5 inhibition by MF.(+)-Morelloflavone (MF) is an antitumor biflavonoid that is found in the  Kinesins are among the most explored protein families in protein–ligand interaction studies, probably owing to their important roles in essential cellular processes, such as cargo transport, neuronal development, and cell division. The mitotic kinesins play particular functions in bipolar spindle assembly, centrosomes separation, and faithful chromosomal segregation into daughter cells during mitosis, and other roles in microtubule polymer dynamics as well as in signal transduction ,3,4,5,6.Previous studies have revealed binding pockets on Eg5 where inhibitors can interact. These binding locations include the ATP-binding site (active site). Only few compounds, such as thiazoles , are knoGarcinia spp., has been reported for its antitumor effect in vivo [Morelloflavone (MF), a biflavonoid isolated from  in vivo . Recentl in vivo . MF inhi in vivo . The inhGarcinia biflavonoid having a luteolin–apigenin structure [S-trityl-l-cysteine (STLC) [tructure . We invee (STLC) ,15. In tFirst, we monitored the stability of all the complexes during the simulation timeframe, using the root means square deviation (RMSD) to observe when the trajectories plateaued and converged towards an equilibrium state. As shown in The RMSD value of Eg5-ATP-MF was relatively low, as the system converged around 1.01 ± 0.35 Å B. In theTo verify the stability of the complexes, we checked the biosystem structures in the presence and absence of inhibitors using radius of gyration (Rg) analysis. As presented in STLC and ispinesib reportedly both bind the allosteric pocket formed by the loop5/α2/α3, despite having diverse chemical structures ,35,36. BThis observation on the loop5/α2/α3 pocket of Eg5 was further substantiated by evaluating the distance between Tyr211 and Trp127. The distance between these residues decreased significantly in Eg5-ADP-MF and Eg5-ADP-STLC structures compared to Eg5 structures in the absence of inhibitors C, suggesTo better understand the local effect of MF and other inhibitors on the Eg5 loop5/α2/α3 pocket, we investigated the degree of movement associated with the binding site throughout the simulation in more detail, within a distance of 8 Å in all directions around the inhibitors. In this range, we found the residues Thr112, Phe113, Met115, Glu116, Gly117, Glu118, Arg119, Ser120, Trp127, Glu128, Leu132, Ala133, Gly134, Ile136, Pro137, Arg138, Leu171, Leu172, Tyr211, Ile213, Leu214, Glu215, Lys216, Ala218, Ala219, Lys220, Arg221, Thr222, and Phe239, which were used to prepare an index file. The RMSD plots for the allosteric pocket in the Eg5-ADP and Eg5-ATP complexes were unsteady, with high fluctuations of up to 0.6 Å A,B. ThisTo explore the structural behavior of Eg5 in the presence or absence of MF, we estimated the distance between selected regions, such as switch I, switch II, α-helix 4 and the central β-sheet (β6) of ADP-bound Eg5, and compared the data with those obtained for STLC and ispinesib. Switch I encompasses residues Met228–Ser235  where the inhibitors are tightly bound to Eg5 via their numerous charge contacts. This effectively restricts the inhibitors’ rotational freedoms such that similar behavior is observed across all trajectories.Transition state  where inhibitors must undergo some rotation to break out. In this region, the interactions between inhibitors and Eg5 are gradually broken. This corresponds to increasing rotational freedom in the molecules.Electrostatic region  where all direct contacts have been severed and residual electrostatic interactions have been screened by incoming water molecules. Under weak electrostatic attractions, the inhibitor molecules are more or less rotationally free.To quantify the effects of small modifications on the complexes, and provide a means to the partition of free energy, the ligand dissociations energies of Ispinesib, STLC, and MF in the Eg5 model were determined from umbrella sampling. Umbrella sampling results showed that MF has very similar energy values to STLC, a known Eg5 inhibitor. We also found that there are many correspondences between the barrier heights of Eg5-ADP-STLC and Eg5-ADP-MF, suggesting similar ways to obtain dissociation complexes. These data confirm that MF is a promising Eg5 inhibitor.The Molecular Mechanics Poisson–Boltzmann Surface Area (MM/PBSA) method was also used to calculate the complexes overall free Gibbs energy . Snapshots of trajectories from 100 ns simulations at every 10 ps of stable intervals were retrieved to serve as inputs for free energy determination. The binding free energies and their corresponding components for Eg5-inhibitor complexes are presented in 50 = 3 nM) [Notably, electrostatic interaction was a predominant contributor to the total binding energy in all the complexes, whereas Van der Waals interaction energy contributed the least. For STLC and MF complexes, the contributions of all energy terms were comparable. This is consistent with data from umbrella sampling . However = 3 nM) .The active site of Eg5 in complex with ATP had lower RMSD values and was relatively more stable than the ADP counterpart B. This iThe chemical structure of MF was built from data retrieved from the literature . ChemAxo++ server [+/Cl- ions (0.15 M). Prior to proceeding to minimization and dynamics, the geometry of the ligands was optimized at the B3LYP/6-31G* level using G09 [Energetic parameters for ADP and ATP were obtained from the AMBER parameter database . Inhibit+ server  was used+ server . A cubic+ server  was carrsing G09 , to obtasing G09 ,58. The Groningen Machine for Chemical Simulations (GROMACS) version 5.0 ,60 was ug_dist tool was used to estimate the distance between residues [binding) of Eg5-inhibitors complexes was determined by the MM/PBSA method using the g_mmpbsa tool [MD trajectories generated during 100 ns were analyzed using GROMACS toolkit utilities. RMSF, RSMD, Rg and hydrogen bond distribution for each system were determined . The g_dresidues . Umbrellresidues  along thresidues . Free bibsa tool . Snapshobsa tool ,74,75. Pbsa tool  and CHIMbsa tool  softwarebsa tool ,79.Eg5 is a validated target for antimitotic agents owing to its importance in cell division. As MF (an anticancer biflavonoid) was previously found to inhibit Eg5 activities, we investigated the dynamics of the Eg5-MF interaction at the molecular level using atomistic simulation to explain the inhibitory mechanism of the biflavonoid. MF displayed tight binding on the loop5/α2/α3 pocket of Eg5 in a manner similar to STLC and ispinesib, which implies that the allosteric pocket is its binding site on Eg5. MF binding induced closure of the allosteric pocket through trapping the loop5 in the “closed” conformation, comparable with the previously reported Eg5 crystal structures co-crystallized with potent inhibitors. Structural modifications of the tubulin-binding region in the presence of MF can compromise the normal binding mode of Eg5 with microtubules as one of the MF mechanisms for inhibiting Eg5 ATPase and motility functions. Upon MF binding, the Eg5 allosteric pocket becomes very compact and stabilized, suggesting a more rigid structure that can contribute to the trapping of Eg5 in the ADP-bound conformation.Taken together, our data show that the inhibition of Eg5 activities by MF indeed involves a stable interaction with the protein at the putative allosteric pocket, and alteration of the conformation of the enzyme. In vivo experiments to confirm the inhibitory mechanisms of morelloflavone against Eg5 and crystallization of Eg5-nucleotide-MF will be undertaken in our subsequent research work to gain more insights on the evolution and biochemical implication of the molecular structure of the complexes.


We examined associations between sugar-sweetened beverage (SSB) intake — a chronic disease risk factor — and characteristics of 75,029 adults (≥18 y) in 9 states by using 2016 Behavioral Risk Factor Surveillance System (BRFSS) data. We used multinomial logistic regression to estimate adjusted odds ratios for SSB intake categorized as none (reference), fewer than 1 time per day, and 1 or more times per day, by sociodemographic and behavioral characteristics. Overall, 32.1% of respondents drank SSBs 1 or more times per day. We found higher odds for 1 or more times per day among younger respondents, men, Hispanic and non-Hispanic black respondents, current smokers, respondents residing in nonmetropolitan counties, employed respondents, and those with less than high school education, obesity, and no physical activity. Our findings can inform the targeting of efforts to reduce SSB consumption. Sugar-sweetened beverages (SSBs) — nondiet soda, fruit drinks that are not 100% juice, sweet tea, sports drinks, and energy drinks — are the largest source of added sugars in the diet of US adults . Frequen2 tests to examine whether frequency of SSB intake differed by population subgroup (significant at P < .05). We performed exploratory multinomial logistic regression, using complete case analysis  and complex survey design sampling weights, to estimate adjusted odds ratios (AORs) for SSB intake of fewer than 1 time per day and 1 or more times per day (reference: none), by all characteristics in the model: state, age, sex, race/ethnicity, education, marital status, employment status, weight status, smoking status, alcohol intake, leisure-time physical activity, and metropolitan status , a state-based random-digit–dial telephone survey of US adults, conducted annually to monitor health conditions and behaviors. BRFSS uses multistage, stratified sampling to select a representative sample of noninstitutionalized adults in each state, the District of Columbia, and selected US territories. Nine states included questions from the SSB optional module in 2016: Delaware, Indiana, Iowa, Mississippi, New Jersey, New York, Ohio, Texas, and West Virginia. These states had a median combined landline and cell phone response rate of 43.0%  . SSB ques n = 67,65 and coOf the 75,029 respondents in 9 states, 47.9% were men and 52.1% were women . Most weP < .001 by χ2 test). The prevalence of SSB intake of 1 or more times per day was higher among men (35.5%) than among women. By age group, it was highest among respondents aged 18 to 24 years (43.4%); by race/ethnicity, it was highest among Hispanic respondents (37.6%) and non-Hispanic black respondents (37.2%); by education, highest among those with some high school education (44.2%); by marital status, highest among respondents who were single (39.8%); by employment status, highest among respondents not employed (35.5%); by smoking status, highest among current smokers (51.6%); by weight status, highest among respondents with obesity (36.9%); by metropolitan status, higher among residents of nonmetropolitan counties (39.3%); by alcohol intake, highest among respondents who consumed no alcohol in the past month (34.7%); and by leisure-time physical activity, higher among respondents who had no physical activity in the past month (38.8%).SSB intake differed by state, age, sex, race/ethnicity, education, marital status, employment status, weight status, smoking status, alcohol intake, leisure-time physical activity, and metropolitan status  versus those aged 55 or older; men (AOR = 1.66) versus women; Hispanic (AOR = 1.43) and non-Hispanic black respondents (AOR = 1.65) versus non-Hispanic white respondents; respondents who did not complete college  versus those who completed college; respondents who were employed (AOR = 1.30) versus those not employed; respondents with obesity (AOR = 1.40) versus those who were underweight/normal weight; current smokers (AOR = 2.44) versus nonsmokers; respondents who did not participate physical activity in the past month (AOR = 1.39) versus those who did participate; and residents of nonmetropolitan counties (AOR = 1.36) versus metropolitan counties . Odds foDaily SSB consumption among adults is high in the United States and varies across states and subgroups. Among 9 states surveyed in 2016, nearly 1 in 3 adults consumed SSBs 1 or more times per day. In the 2013 BRFSS, which included 23 states and the District of Columbia, 29.1% of respondents were daily consumers . Our finWe found that respondents with obesity had significantly higher odds of consuming SSBs 1 or more times per day than underweight or normal-weight respondents. Longitudinal studies have documented the association between daily SSB intake and weight gain ,4. PreviOur study has several limitations. BRFSS data are self-reported; however, potential bias in SSB intake data related to self-report or social desirability is not known. Our analysis included only 9 states that asked SSB questions; thus, the findings might not be generalizable to other states. Finally, the amount or calorie intake from SSBs cannot be estimated, because data on SSB intake was captured as frequency rather than volume. Our findings that adult SSB intake varied across states and certain characteristics can be used to help inform efforts to reduce SSB consumption.


Superior catalytic performances in these reactions have been demonstrated. Challenges and future developments are finally addressed.Nanoparticle/metal–organic frameworks (MOF) based composites have recently attracted significant attention as a new class of catalysts. Such composites possess the unique features of MOFs , but avoid some intrinsic weaknesses . This review summarizes the developed strategies for the fabrication of nanoparticle/MOF composites for catalyst uses, including the strategy using MOFs as host materials to hold and stabilize the guest nanoparticles, the strategy with subsequent MOF growth/assembly around pre-synthesized nanoparticles and the strategy mixing the precursors of NPs and MOFs together, followed by self-assembly process or post-treatment or post-modification. The applications of nanoparticle/MOF composites for CO oxidation, CO Metal–organic frameworks (MOFs) are a class of highly porous crystalline materials, which are assembled by the coordination of metal ions with organic ligands ,2,3,4. DIn term of catalytic application, MOF composites show some superior characteristics because of the unique features of MOFs mentioned above. For example, high porosity with ordered crystalline pores and high surface areas contribute to the uniform dispersion and the high density of catalytic sites, which can improve the catalytic efficiency . The con2 conversion, hydrogen production, organic reaction and pollutants remediation, and so on, over nanoparticle/MOF composite based catalysts  and “bottle around ship” approach, respectively . A. A2, to 87 wt %) b. In add3N4 [2 increases the photoactivity for the HER and was superior to Pt as a co-catalyst [2/UiO-66-CdS obtained a high H2 evolution rate of 25,770 µmol·g−1·h−1, approximately 2-fold higher than that of 1 wt % Pt/UiO-66-CdS. Lin et al. [4P2 POMs into the pores of highly stable MOFs. The integration of the photosensitizing MOF framework and the POM catalyst allows for facile multi-electron transfer to enable an efficient HER, with turnover numbers as high as 1476.Recently, some functional components, including nickel particles , metal s3N4 , and POM3N4  have beecatalyst . 1 wt % n et al.  reportedMOF composites have been employed as efficient catalysts for the selective oxidation of alcohols, which are commonly considered as the central reactions in organic chemistry. Li et al. ,103,104 13Ag12@MOF composites exhibited favorable catalytic activity in the oxidation of benzyl alcohol toward benzaldehyde, exceeding 75% conversion and 100% selectivity.Other composite systems, including Au NPs, metal nanoclusters, POMs, CdS, and rGO, also exhibit high catalytic activities for selective oxidation of various alcohol substrates to aldehydes ,110,111.−1) with >80% selectivity to KA-oil under mild solvent-free conditions. Recently, Hx3+PMox12−VxO40@MIL-100 (Fe)  hybrids were prepared by the encapsulation of POMs within a metal–organic framework using a hydrothermal method [2O2 as green oxidant. In particular, the hybrid H4PMo11VO40@MIL-100 (Fe) leads to 85% cyclohexene conversion, 91% selectivity for 2-cyclohexene-1-one under optimized conditions, as well as excellent stability and reusability.Besides, the aerobic oxidation of hydrocarbons catalyzed by MOF based nanohybrid catalysts has also been explored. Various active species, including Au, AuPd, PtPd alloy NPs, POMs, and grapheme oxide (GO), combined with several MOFs were proved to be active and selective in the oxidation hydrocarbons with molecular oxygen ,114,115.l method . The hybHydrogenation is a key reaction that is extensively employed in industry. The Pd, Pt, Ru, and Ni NPs, and their bimetallic NPs immobilized by MOFs have been proven to be active catalysts in the hydrogenation of a wide range of substrates including alkenes ,119,120,n-hexene, approximately 100% conversion can be achieved, while large molecules, such as cyclooctene (5.5 Å), cannot access the ZIF-8 shell with a pore aperture of (3.4 Å), resulting in negligible conversion. More interestingly, the catalytic performance of the Pd NCs@ZIF-8 composite in the hydrogenation of n-hexene is significantly improved by light irradiation ), and so on. It is necessary to reduce the concentration of pollutants before discharging the wastewater into the aquatic environment. Otherwise, various environmental and health issues could be induced. Among the physical, chemical, and biological technologies that are applied for the removal of pollutants, heterogeneous catalysis, including photocatalysis, has been demonstrated to be an efficient, economical, and green technique to degrade pollutants into easily biodegradable or less toxic compounds. Recently, MOF based composites with noble metal NPs, metal oxide/sulfides, GO, and other compounds have been proved to be a new class of catalysts, which are usable in the catalytic degradation of organic pollutants and Cr(VI) ,158,159.•OH, •O2−, •OOH, and •SO4− [Advanced oxidation processes (AOPs) are increasingly adopted for the degradation of organic pollutants, owing to the in situ generation of highly reactive and nonselective radicals, such as nd •SO4− . In AOPs3O4@MIL-100(Fe) composite with a magnetic core and a designable MOF shell. This magnetic recyclable composite exhibits photocatalytic activity for methylene blue (MB) degradation under both UV-vis and visible light irradiation with good recycling stability. Based on a similar process, a yolk-shell Co3O4@MOF was successfully prepared via the fabrication of a uniform Fe-doped MOF-5 shell around Co3O4 NPs [3O4@MOF composite with satisfactory reusability.Qiu et al.  firstly o3O4 NPs . The deg2S3@MIL-125(Ti) photocatalytic adsorbent, which was prepared by a facile solvothermal method. The integrated composite exhibits excellent adsorption affinity, as well as superior photocatalytic activity, for the removal of tetracycline (TC). The photo-degradation efficiency for TC within a 60-min visible light irradiation is 63.3%, which is much higher than that of bare In2S3 or MIL-125(Ti), indicating the beneficial synergistic effect between MIL-125(Ti) and In2S3. The core–shell composites also reveal good performance for the removal of TC from various real wastewaters. Similarly, the CdS/MIL-53(Fe) and CdTe QDs/Eu-MOF composites show high photocatalytic activity in the degradation of Rhodamine B (RhB) and Rhodamine 6G in water at room temperature under light irradiation [Recently, Yuan et al.  reportedadiation ,146. X, X = Cl, Br, I) and MOFs composites are also effective in improving photocatalytic performance. BiOBr/UIO-66, BiOBr/NH2-MIL125(Ti), BiOBr/CAU-17, and BiOI/MIL-88B(Fe) nanocomposites have been reported as highly efficient photocatalysts for the degradation of organic pollutants [Alternatively, the bismuth oxyhalides  by a facile solvothermal method. The resulting g-C3N4/MIL-125(Ti) composite catalyst exhibits an excellent catalytic performance with good reusability and stability. The optimal photocatalytic performance is obtained at the g-C3N4 content of 7 wt % for MIL-125(Ti), on which the rate of RhB photodegradation is 0.0624 min−1, which is about 2.1 and 24 times higher than that of pure g-C3N4 and MIL-125(Ti), respectively.Unlike metal semiconductor photocatalysts, g-Cradation ,144. Yuaradation  successfCatalytic reductive transformation of Cr(VI) to Cr(III) is a promising method to perform effective remediation of Cr(VI), because Cr(III) is much less toxic and can be easily precipitated and removed due to its lower solubility in water in contrast to highly water-soluble and toxic Cr(VI).2 and CO2, according to Equation (1). The generated hydrogen, with high reduction capacity, then reduces Cr(VI) into Cr(III), as shown in Equation (2):Xu, Yu and Trivedi’s groups reported active MOF-supported noble metal  NPs catalysts for the reduction of Cr(VI) to Cr(III) using formic acid ,152,157.2 is highly active to almost completely reduce Cr(VI) into Cr(III) within 90 min under visible light irradiation (λ ≥ 420 nm) at a pH range of 1–5, which is ascribed to the intimate interfacial contact between Pd and UiO-66-NH2, leading to the efficient charge separation. More interestingly, the reduction of Cr(VI) is visibly enhanced when the organic dye (MB or methyl orange (MO)) is added into the reaction system. In the binary systems of Cr(VI)/MO and Cr(VI)/MB, the reduction ratios of Cr(VI) are 79% and ~100%, respectively, which are obviously higher than that in the single system (70%)  b. Meanwh2 and rGO-MIL-53(Fe) nanocomposites were successfully assembled by electrostatic attractive force for surface attachment [2 and MIL-53(Fe), for which the reduction ratio of Cr(VI) is even up to 100% under visible light illumination within 100 min and 80 min, respectively.Moreover, the rGO-UiO-66-NHtachment ,159. TheRecently, Wang et al.  employedMOFs have been considered as ideal catalysts with clearly defined and designable crystal structures, high surface areas, tunable and uniform pore structures, and special confined nanopore microenvironments . Some in2 conversion, hydrogen production, organic reaction, and pollutant degradation. The high catalytic performances are contributed to the beneficial synergistic effects of MOFs and active sites of NPs. Significantly increasing applications of MOF based NP composite catalysts can be expected.The present studies have demonstrated that the MOF based NP composite catalysts exhibit excellent catalytic performances for CO oxidation, CO(1)A principal advantage of MOFs is their designable structure with clear chemistry. When metal or metal oxide NPs are introduced, not clear chemistry may be caused because of not only various complex issues of NPs (like defects), but the interaction between MOFs and NPs. This is the most significant challenge for the future development with opportunities. In order to develop a size, structure, and location controllable preparation of NP/MOF composites, the interaction between metal or metal oxide and the MOF support needs to be further investigated. The functionalization and modification of MOFs needs to be also further investigated. The involvement of organic links in the catalytic reaction and the formation of intrinsic structure of MOFs with NPs generate many fundamental thermodynamic and kinetic issues for catalyst investigations. The reported studies are mostly limited within the experimental exploitation of MOFs for various reactions. Regarding the difficulty in the catalyst characterization, more theoretical studies are needed ,161,162.(2)For the composites by the pre-synthesized NPs, the polymer capping agent, like PVP, has some negative effects on the catalytic properties. Alternatives to such agents should be investigated. In this regard, biomolecules, like peptide, can be a nice candidate ,164,165.(3)Since MOFs are now mostly thermal sensitive materials, innovation in the post treatment or modification of the NP/MOF composites at low temperatures is extremely important. We attempted to use the room temperature electron reduction ,167 for (4)An important future direction is the preparation of NP/MOF composites, together with gels, graphene, porous polymers, ionic liquids, and others, especially for the blooming photocatalytic and photo-electro-catalytic applications ,169.(5)The development of MOF based solid acid and solid base will create more opportunities for NP/MOF composite catalysts .(6)MOF itself has been demonstrated to be an excellent single site catalyst, with which metal nodes in MOFs mimic homogeneous catalysts not only functionally but also mechanistically ,172. It However, MOF composites, as heterogeneous catalysts, are still under its early developing stage. In the view of structural features, MOF composites consist of active species, metal ions and organic ligands, which are the potential factors influencing the catalytic performance. The relationship between the catalytic behavior and the structural features still needs to be investigated further. Further improvement in the thermal and chemical stability of MOFs is required. The present syntheses of MOFs are not cheap. Some syntheses are complex and time consuming, with difficulty in the scaling up. Innovation in the syntheses of MOFs is one of the future developments. Besides the improvement in the syntheses of MOFs for catalyst uses, the following studies are expected to further lead the progresses in the MOF composite catalysts: