The accumulation of reactive oxygen species （ROS） is involved in plant cell development. In plant, class III peroxidases are heme-containing enzymes encoded by a large multi-gene family participated in the release o...The accumulation of reactive oxygen species （ROS） is involved in plant cell development. In plant, class III peroxidases are heme-containing enzymes encoded by a large multi-gene family participated in the release or consumption of ROS. The specific function of each member of the family is still elusive. Here, we showed that ROS was significantly generated during cotton fiber initiation and elongation, whereas, application of NADPH oxidase inhibitor diphenyleneiodonium （DPI） and peroxidase inhibitor salicylhydroxamic acid （SHAM） to the wild-type cotton ovule culture significantly suppressed fiber growth, respectively. Their inhibitory effects were caused by the reduction of superoxide radical （O2^-）. Ten GhPOX genes （cDNAs） encoding cotton class III peroxidases were isolated, among them eight GhPOX genes were reported for the first time. Microarray analyses indicated that GhPOX1 was the mostly predominantly expressed in fast-elongating cotton fiber cells. Real-time quantitative PCR analysis revealed the transcript level of GhPOX1 was over 400-fold higher in growing fiber cells than in ovules, flowers, roots, stems and leaves. To reveal the role of GhPOX1 in plant development, its Arabidopsis orthologue atpox13 mutant was demonstrated to be defective in branch root development. Taken together, the data suggest that GhPOX1 plays an important role during fiber cell elongation possibly by mediating production of reactive oxygen species.展开更多
N-acetylglucosaminyltransferase V （GnT-V） is an important tumorigenesis and metastasis-associated enzyme. To study its biofunction, the GnT-V stably suppressed cell line （GnT-V-AS/7721） was constructed from 7721 h...N-acetylglucosaminyltransferase V （GnT-V） is an important tumorigenesis and metastasis-associated enzyme. To study its biofunction, the GnT-V stably suppressed cell line （GnT-V-AS/7721） was constructed from 7721 hepatocarcinoma cells in previous study. In this study, cDNA array gene expression profiles were compared between GnT-V-AS/7721 and parental 7721 cells. The data indicated that GnT-V-AS/7721 showed a characteristic expression pattern consistent with the ER stress. The molecular mechanism of the ER stress was explored in GnT-V-AS/7721 by the analysis on key molecules in both two unfolded protein response （UPR） pathways. For ATF6 and Irel/XBP-1 pathway, it was evidenced by the up-regulation of BIP at mRNA and protein level, and the appearance of the spliced form ofXBP-1. As for PERK/eIF2α pathway, the activation of ER eIF2α kinase PERK was observed. To confirm the results from GriT-V-AS/7721 cells, the key molecules in the UPR were examined again in 7721 cells interfered with the GnT-V by the specific RNAi treatment. The results were similar with those from GnT-V-AS/7721, indicating that blocking of GnT-V can specifically activate ER stress in 7721 cells. Rate of 3H-Man incorporation corrected with rate of 3H-Leu incorporation in GnT-V-AS/7721 was down-regulated greatly compared with the control, which demonstrated the deficient function of the enzyme synthesizing N-glycans after GnT-V blocking. Moreover, the faster migrating form of chaperone GRP94 associated with the underglycosylation, and the extensively changed N-glycans structures of intracellular glycoproteins were also detected in GnT-V-AS/7721. These results supported the mechanism that blocking of GnT-V expression impaired functions of chaperones and N-glycan-synthesizing enzymes, which caused UPR in vivo.展开更多
Objective To prepare monoclonal antibodies against a newly discovered and conserved linear epitope of Rabies virus nucleoprotein and to use them in a rabies diagnostic test. Methods Synthetic peptide containing the ep...Objective To prepare monoclonal antibodies against a newly discovered and conserved linear epitope of Rabies virus nucleoprotein and to use them in a rabies diagnostic test. Methods Synthetic peptide containing the epitope was used as immunogen to prepare hybridoma cell lines by classical hybridoma technology. Anti-peptide monoclonal antibodies produced in ascites of inoculated Balb/c mice were labeled with fluorescein isothiocyanate （FITC） after purification and used in fluorescent antibody test （FAT）. Results Two positive hybridoma cell lines, RVNP-mAbl-CL and RVNP-mAb2-CL, were obtained. RVNP- mAbl-CL produced a higher concentration of monoclonal antibody RVNP-mAbl in Balb/c ascites. FITC-labeled RVNP-mAbl showed correct results on certain Rabies virus-positive canine brain tissue samples and cells of a small subclone of baby hamster kidney 21 cell line （BSR）. Conclusion FITC-labeled RVNP-mAbl has potential application for laboratory diagnosis of rabies展开更多
Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax v...Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension culture.Methods: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate.Results: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold.Conclusions: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.展开更多
Comprehending the diversity of the regenerative potential across metazoan phylogeny represents a fundamental challenge in biology. Invertebrates like Hydra and planarians exhibit amazing feats of regeneration, in whic...Comprehending the diversity of the regenerative potential across metazoan phylogeny represents a fundamental challenge in biology. Invertebrates like Hydra and planarians exhibit amazing feats of regeneration, in which an entire organism can be restored t^om minute body segments. Vertebrates like teleost fish and amphibians can also regrow large sections of the body. While this regenerative capacity is greatly attenuated in mammals, there are portions of major organs that remain regenerative. Regardless of the extent, there are common basic strategies to regeneration, including activation of adult stem cells and proliferation of differentiated cells. Here, we discuss the cellular features and molecular mechanisms that are involved in regeneration in different model organisms, including 14ydra, planarians, zebrafish and newts as well as in several mammalian organs.展开更多
The ASK1 （ARABIDOPSIS SKP1-LIKE） protein is a critical component of the SCF （Skpl-Cullin-F box protein） ubiquitin ligase complexes that recruit target proteins for degradation by the 26S proteosome. To investigate...The ASK1 （ARABIDOPSIS SKP1-LIKE） protein is a critical component of the SCF （Skpl-Cullin-F box protein） ubiquitin ligase complexes that recruit target proteins for degradation by the 26S proteosome. To investigate proteins that are affected by the ASK1-mediated proteolysis pathway in Arabidopsis flowers, we compared the proteomes of the Arabidopsis wild type and ask1 mutant flower buds using two-dimensional electrophoresis （2-DE）. Ten protein spots with higher or lower abundance in the ask1 mutant flowers compared to wild type flowers were excised and subjected to further mass spectrometry （MS） analysis. The results showed that they were proteins involved in photomorphogenesis, circadian oscillation, post-translation process, stress-responses and cell expansion or elongation, suggesting that those processes were affected in the ask1 mutant. The transcript levels of these genes were also compared based on the Affymetrix gene chip microarray data. No significant difference was observed for most of the genes, suggesting that the proteins with elevated levels of accumulation in the ask1 mutant could be candidate targets regulated by an ASK 1-mediated proteolysis pathway. These results help to elucidate the pleiotropic functions of ASK1 in Arabidopsis developmental processes and also demonstrate the importance and necessity of studying protein levels with respect to gene functions.展开更多
The COP9 signalosome （CSN） is a multiprotein complex which participates in diverse cellular and developmental processes. CSN1, one of the subunits of CSN, is essential for assembly of the multiprotein complex via P...The COP9 signalosome （CSN） is a multiprotein complex which participates in diverse cellular and developmental processes. CSN1, one of the subunits of CSN, is essential for assembly of the multiprotein complex via PCI （proteasome, COP9 signalosome and initiation factor 3） domain in the C-terminal half of CSN 1. However, the role of the N-terminal domain （NTD） of CSN 1, which is critical for the function of CSN, is not completely understood. Using a yeast two-hybrid （Y2H） screen, we found that the NTD of CSN1 interacts with TSK-associating protein 1 （TSA1）, a reported CaZ＋-binding protein. The interaction between CSN1 and TSA1 was confirmed by co-immunoprecipitation in Arabidopsis. tsal mutants exhibited a short hypocotyl phenotype in darkness but were similar to wild-type Arabidopsis under white light, which suggested that TSA1 might regulate Arabidopsis hypocotyl development in the dark. Furthermore, the expression of TSA1 was significantly lower in a csnl null mutant （fus6）, while CSN1 expression did not change in a tsal mutant with weak TSAI expression. Together, these findings suggest a functional relationship between TSAI and CSN1 in seedling development.展开更多
Melanocortin 4 receptor(MC4R),the most important monogenetic cause of human metabolic disorders,has been of great interest to many researchers in the field of energy homeostasis and public health.Because MC4R is a vit...Melanocortin 4 receptor(MC4R),the most important monogenetic cause of human metabolic disorders,has been of great interest to many researchers in the field of energy homeostasis and public health.Because MC4R is a vital pharmaceutical target for maintaining controllable appetite and body weight for professional athletes,previous studies have mainly focused on the central,rather than the peripheral,roles of MC4R.Thus,the local expression of MC4R and its behavioral regulation remain unclear.In an attempt to shed light on different directions for future studies of MC4R signaling,we review a series of recent and important studies exploring the peripheral functions of MC4R and the direct physiological interaction between peripheral organs and central MC4R neurons in this article.展开更多
Osteoporosis(OP),a systemic and chronic bone disease,is distinguished by low bone mass and destruction of bone microarchitecture.Ginsenoside Compound-K(CK),one of the metabolites of ginsenoside Rb1,has anti-aging,anti...Osteoporosis(OP),a systemic and chronic bone disease,is distinguished by low bone mass and destruction of bone microarchitecture.Ginsenoside Compound-K(CK),one of the metabolites of ginsenoside Rb1,has anti-aging,anti-inflammatory,anti-cancer,and hypolipidemic activities.We have demonstrated CK could promote osteogenesis and fracture healing in our previous study.However,the contribution of CK to osteoporosis has not been examined.In the present study,we investigated the effect of CK on osteoclastogenesis and ovariectomy(OVX)-induced osteoporosis.The results showed that CK inhibited receptor activator for nuclear factor-κB ligand(RANKL)-mediated osteoclast differentiation and reactive oxygen species(ROS)activity by inhibiting the phosphorylation of NF-κB p65 and oxidative stress in RAW264.7 cells.In addition,we also demonstrated that CK could inhibit bone resorption using bone marrow-derived macrophages.Furthermore,we demonstrated that CK attenuated bone loss by suppressing the activity of osteoclast and alleviating oxidative stress in vivo.Taken together,these results showed CK could inhibit osteoclastogenesis and prevent OVX-induced bone loss by inhibiting NF-κB signaling pathway.展开更多
Pancreatic cancer is among the most malignant cancers,and thus early intervention is the key to better survival outcomes.However,no methods have been derived that can reliably identify early precursors of development ...Pancreatic cancer is among the most malignant cancers,and thus early intervention is the key to better survival outcomes.However,no methods have been derived that can reliably identify early precursors of development into malignancy.Therefore,it is urgent to discover early molecular changes during pancreatic tumorigenesis.As aberrant glycosylation is closely associated with cancer progression,numerous efforts have been made to mine glycosylation changes as biomarkers for diagnosis;however,detailed glycoproteomic information,especially site-specific N-glycosylation changes in pancreatic cancer with and without drug treatment,needs to be further explored.Herein,we used comprehensive solid-phase chemoenzymatic glycoproteomics to analyze glycans,glycosites,and intact glycopeptides in pancreatic cancer cells and patient sera.The profiling of N-glycans in cancer cells revealed an increase in the secreted glycoproteins from the primary tumor of MIA PaCa-2 cells,whereas human sera,which contain many secreted glycoproteins,had significant changes of glycans at their specific glycosites.These results indicated the potential role for tumor-specific glycosylation as disease biomarkers.We also found that AMG-510,a small molecule inhibitor against Kirsten rat sarcoma viral oncogene homolog(KRAS)G12C mutation,profoundly reduced the glycosylation level in MIA PaCa-2 cells,suggesting that KRAS plays a role in the cellular glycosylation process,and thus glycosylation inhibition contributes to the anti-tumor effect of AMG-510.展开更多
Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensi...Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensive systematic search was conducted in PubMed, Web of Science, SPORTDiscus, Cochrane Library electronic databases, and other sources before April 5, 2021. Fourteen studies were included in the systematic review, involving 855 athletes and 521 control subjects. Serum magnesium concentration was significantly lower in athletes(mean difference(MD):-0.04 mmol/L;95% confidence interval(CI):-0.06 to-0.01;P = 0.02)in spite of significantly higher dietary magnesium intake(MD: 51.72 mg/day;95% CI: 14.62 to 88.83;P = 0.006). Meta-analysis showed that 24-h urinary magnesium excretion in athletes was significantly higher than that in the untrained population(MD: 0.76 mmol/day;95% CI: 0.11 to 1.41;P = 0.02). Despite higher total dietary magnesium intake, athletes generally have lower serum magnesium concentration and higher 24-h urinary magnesium excretion, demonstrating that the magnesium requirement of athletes is higher than the untrained population. It is necessary to carry out a dietary assessment and nutrition counseling to help athletes adopt proper diets to meet their nutritional needs in exercise.展开更多
Although the compositional alterations of gut bacteria in ketogenic diet(KD)have been intensively investigated,the causal relationship between this extreme diet and the microbiota changes is not fully understood.Here,...Although the compositional alterations of gut bacteria in ketogenic diet(KD)have been intensively investigated,the causal relationship between this extreme diet and the microbiota changes is not fully understood.Here,we studied the growth dynamics of intestinal bacteria in KD.We used the CoPTR method to calculate the peak-to-trough ratio(PTR)based on metagenomic sequencing data,serving as an indicator of bacterial growth rates.Notably,Akkermansia muciniphila,a bacterium strongly linked to the therapeutic benefits of KD,exhibited one of the highest growth rates,aligning with its markedly elevated abundance.Our findings also revealed discrepancies in the change patterns of CoPTR values and relative abundances for various bacteria across different diet groups,some of which might be attributed to the exceptionally high or low growth rates of specific species.For some of the species demonstrating obvious differences in growth rates between KD and standard diet,we conducted in vitro culture experiments,supplementing them with diverse nutritional sources to elucidate the underlying mechanisms.The integrative analysis of bacterial abundance and growth dynamics can help deepen our understanding of the gut microbiota changes caused by KD and the therapeutic effects of this special diet.展开更多
Abscisic acid （ABA） and brassinosteroid （BR） antagonistically regulate many aspects of plant growth and development. Previous physiological studies have revealed that the inhibition of BR signaling by ABA is large...Abscisic acid （ABA） and brassinosteroid （BR） antagonistically regulate many aspects of plant growth and development. Previous physiological studies have revealed that the inhibition of BR signaling by ABA is largely dependent on ABI1 and ABI2. However, the genetic and molecular basis of how ABI1 and ABI2 are involved in inhibiting BR signaling remains unclear. Although it is known that in the BR signaling pathway the ABA-BR crosstalk occurs in the downstream of BR receptor complex but upstream of BIN2 kinase, a negative regulator of BR signaling, the component that acts as the hub to directly mediate their crosstalk remains a big mystery. Here, we found that ABI1 and ABI2 interact with and dephosphorylate BIN2 to regu- late its activity toward the phosphorylation of BESl. Byin vitro mimicking ABA signal transduction, we found that ABA can promote BIN2 phosphorylation by inhibiting ABI2 through ABA receptors. RNA-sequencing analysis further demonstrated that ABA inhibits BR signaling through the ABA primary signaling components, including its receptors and ABI2, and that ABA and GSK3s co-regulate a common set of stress- responsive genes. Because BIN2 can interact with and phosphorylate SnRK2s to activate its kinase activity, our study also reveals there is a module of PP2Cs--BIN2-SnRK2s in the ABA signaling pathway. Collectively, these findings provide significant insights into how plants balance growth and survival by coordinately regu- lating the growth-promoting signaling pathway and stress responses under abiotic stresses.展开更多
Protein size is an important biochemical feature since longer proteins can harbor more domains and therefore can display more biological functionalities than shorter proteins. We found remarkable differences in protei...Protein size is an important biochemical feature since longer proteins can harbor more domains and therefore can display more biological functionalities than shorter proteins. We found remarkable differences in protein length, exon structure, and domain count among different phylo- genetic lineages. While eukaryotic proteins have an average size of 472 amino acid residues （aa）, average protein sizes in plant genomes are smaller than those of animals and fungi. Proteins unique to plants are -81 aa shorter than plant proteins conserved among other eukaryotic lineages. The smaller average size of plant proteins could neither be explained by endosymbiosis nor subcellular compartmentation nor exon size, but rather due to exon number. Metazoan proteins are encoded on average by -10 exons of small size [-176 nucleotides （nt）]. Streptophyta have on average only -5.7 exons of medium size （-230 nt）. Multicellular species code for large proteins by increasing the exon number, while most unicellular organisms employ rather larger exons （ 〉 400 nt）. Among subcellular compartments, membrane proteins are the largest （-520 aa）, whereas the smallest proteins correspond to the gene ontology group of ribosome （-240 aa）. Plant genes are encoded by half the number of exons and also contain fewer domains than animal proteins on average. Interestingly, endosymbiotic proteins that migrated to the plant nucleus became larger than their cyanobacterial orthologs. We thus conclude that plants have proteins larger than bacteria but smaller than animals or fungi. Compared to the average of eukaryotic species, plants have -34% more but -20% smaller proteins. This suggests that photosynthetic organisms are unique and deserve therefore special attention with regard to the evolutionary forces acting on their genomes and proteomes.展开更多
Chlorophyllase （EC 3.1.1.14） is involved in the first step of chlorophyll degradation. Isolation of chlorophyllase genes greatly facilitates characterization of chlorophyllase properties and elucidation of molecular...Chlorophyllase （EC 3.1.1.14） is involved in the first step of chlorophyll degradation. Isolation of chlorophyllase genes greatly facilitates characterization of chlorophyllase properties and elucidation of molecular regulation of their in vivo activities. There are two chlorophyllase genes, AtCLH1 and AtCLH2, in Arabidopsis thaliana. The in vivo roles of AtCLH1 have been reported previously. However, few studies have been carried out on AtCLH2. Here, we show that purified recombinant Chlase2, encoded by AtCLH2, exhibits in vitro chlorophyllase activity. Interestingly, ＂activation＂ of in vitro activity of the recombinant Chlase2 required higher concentrations of a detergent or a polar solvent. To determine its activity in vivo, the expression of AtCLH2 was inhibited by RNA interference. RNAi plants showed decreased contents of chlorophyllide without a substantial change in the total amount of the extractable chlorophyll and consequently presented lower chlorophyllide to chlorophyll ratios in their leaves. In addition, the two AtCLHs exhibited differential expression patterns. Our results suggest that AtCLH2 might play a distinctive role in chlorophyll catabolism in vivo.展开更多
Hundreds of leucine-rich repeat receptor-like kinases （LRR-RLKs） play indispensable roles in a wide range of plant developmental and physiological processes. The mechanisms controlling LRR-RLKs at a basal and inacti...Hundreds of leucine-rich repeat receptor-like kinases （LRR-RLKs） play indispensable roles in a wide range of plant developmental and physiological processes. The mechanisms controlling LRR-RLKs at a basal and inactive status are essential but rarely studied. BKI1 is the only reported inhibitor of receptor kinases in Arabidopsis, which negatively regulates BRI1 in the brassinosteroid pathway. In this study, we found that BKI1 can also interact with another important LRR-RLK, ERECTA （ER）. Phenotypic analysis showed that BKI1 and ER together regulate plant architecture, including pedicel orientation, which is a newly reported phenotype in the BR- and ER-mediated developmental processes. Gene expression analysis revealed that BKI1 regulates a subset of ER-responsive genes. Kinase assays demonstrated that BKI1 inhibits ER kinase activity. In addition, the release of BKI1 inhibition on ER signaling relies largely on BRI1 activation. Our data provide significant insights into the regulation and activation of RLKs and suggest that BKI1 functions as a common suppressor of the BRI1 and ER signaling pathways.展开更多
Unlike animals, plants do not set aside germ cells early in development. In angiosperm species, reproduction occurs in the adult plant upon flowering. The multicellular male and female gametophytes differentiate from ...Unlike animals, plants do not set aside germ cells early in development. In angiosperm species, reproduction occurs in the adult plant upon flowering. The multicellular male and female gametophytes differentiate from meiotic products within reproductive floral organs. Double fertilization is another remarkable feature of most angiosperm species. The zygote derived from fertilization of the egg cell by one of the sperm cells and the endosperm from fertilization of the central cell by the second sperm cell develop in a coordinated manner together and enclosed in the sporophytic maternal integuments, forming the seed. Understanding plant reproduction is biologically pertinent and agronomically and ecologically important. Here, we describe the known functions of histone lysine methylations in various steps of reproduction in the reference plant Arabidopsis thaliana. It is emerging that histone lysine methylation is key for understanding epigenetic regulation networks of genome function.展开更多
Root organogenesis involves cell division, differentiation and expansion. The molecular mechanisms regulating root development are not fully understood. In this study, we identified poly（adenosine diphosphate （ADP）...Root organogenesis involves cell division, differentiation and expansion. The molecular mechanisms regulating root development are not fully understood. In this study, we identified poly（adenosine diphosphate （ADP）-ribose） polymerases （PARPs） as new players in root development. PARP catalyzes poly（ADP-ribosyl）ation of proteins by repeatedly adding ADP-ribose units onto proteins using nicotinamide adenine dinucleotide （NAD ） as the donor. We found that inhibition of PARP activities by 3-aminobenzomide （3-AB） increased the growth rates of both primary and lateral roots, leading to a more developed root system. The double mutant of Arabidopsis PARPs, parplparp2, showed more rapid primary and lateral root growth. Cyclin genes regulating G1-to-S and G2-to-M transition were up-regulated upon treatment by 3-AB. The proportion of 2C ceils increased while cells with higher DNA ploidy declined in the roots of treated plants, resulting in an enlarged root meristematic zone. The expression level of PARP2 was very low in the meristematic zone but high in the maturation zone, consistent with a role of PARP in inhibiting mitosis and promoting cell differentiation. Our results suggest that PARPs play an important role in root development by negatively regulating root cell division.展开更多
In modern agriculture,frequent application of herbicides may induce the evolution of resistance in plants,but the mechanisms underlying herbicide resistance remain largely unexplored.Here,we report the char-acterizati...In modern agriculture,frequent application of herbicides may induce the evolution of resistance in plants,but the mechanisms underlying herbicide resistance remain largely unexplored.Here,we report the char-acterization of rtp 1(resistant to paraquat 1),an Arabidopsis mutant showing strong resistance to the widely used herbicides paraquat and diquat.The rtp1 mutant is semi-dominant and carries a point mutation in the gene encoding the multidrug and toxic compound extrusion family protein DTX6,leading to the change of glycine to glutamic acid at residue 311(G311E).The wild-type DTX6 with glycine 311 conferred weak para-quat and diquat resistance when overexpressed,while mutation of glycine 311 to a negatively charged amino acid(G311E or G311D)markedly increased the paraquat and diquat resistance of plants,whereas mutation to a positively charged amino acid(G311R or G311K)compromised the resistance,suggesting that the charge property of residue 311 of DTX6 is critical for the paraquat and diquat resistance of Arabi-dopsis plants.DTX6 is localized in the endomembrane trafficking system and may undergo the endosomal sorting to localize to the vacuole and plasma membrane.Treatment with the V-ATPase inhibitor ConA reduced the paraquat resistance of the rtp1 mutant.Paraquat release and uptake assays demonstrated that DTX6 is involved in both exocytosis and vacuolar sequestration of paraquat.DTX6 and DTX5 show functional redundancy as the dtx5 dtx6 double mutant but not the dtx6 single mutant plants were more sen-sitive to paraquat and diquat than the wild-type plants.Collectively,our work reveals a potential mecha-nism for the evolution of herbicide resistance in weeds and provides a promising gene for the manipulation of plant herbicide resistance.展开更多
The discrepancy of indoleamine 2,3-dioxygenase 1(IDO1)function in atherosclerosis has been noted.Compared to the protective effect of IDO1 against established atherogenesis,the role of IDO1 in the developmental proces...The discrepancy of indoleamine 2,3-dioxygenase 1(IDO1)function in atherosclerosis has been noted.Compared to the protective effect of IDO1 against established atherogenesis,the role of IDO1 in the developmental process of atherosclerosis is still unclear.Here,the expression patterns and activities of IDO1 and its isoenzyme tryptophan 2,3-dioxygenase(TDO)in aortas and blood samples of patients with atherosclerosis were investigated.IDO1 and TDO were colocalized with CD3-positive lymphocytes and CD68-positive macrophages in atherosclerotic lesions.The expression and activity of IDO1 and TDO increased with the grade of the histological classification in early atherosclerosis(grade I,II),but the increase did not continue in advanced atherosclerosis(grade III).Treatment of THP-1 macrophages(THP-M)with oxidized low-density lipoprotein(oxLDL)induced the expression of IDO1 via the PI3K/Akt/NF-κB pathway,indicating the potential function of IDO1 in foam cells.Before and after treatment with oxLDL on THP-M,IFN-γ-induced IDO1 exhibited different degrees of promotion on foaming,inflammatory factor production and cell apoptosis.Finally,we found that the IDO1 inhibitor 1-methyl-tryptophan could elevate the high-density lipoprotein cholesterol level in serum and reduce the area of the aortic atherosclerotic lesions in high-fat diet-fed ApoE−/−mice.Our study indicated that IDO1 played a complicated and unfixed role in the entire process of atherogenesis,despite the atheroprotective role in established atherosclerosis.IDO1 also had proatherosclerotic functions in the developmental stages of atherosclerosis.Modulation of IDO1 could be a good method for alleviating atherosclerosis.展开更多
基金supported by grants from the National Basic Research Program of China (No. 2004CB117302)the National High-tech Research Program of China (No. 2006AA10A109-1 and 2007AA10Z136).
文摘The accumulation of reactive oxygen species （ROS） is involved in plant cell development. In plant, class III peroxidases are heme-containing enzymes encoded by a large multi-gene family participated in the release or consumption of ROS. The specific function of each member of the family is still elusive. Here, we showed that ROS was significantly generated during cotton fiber initiation and elongation, whereas, application of NADPH oxidase inhibitor diphenyleneiodonium （DPI） and peroxidase inhibitor salicylhydroxamic acid （SHAM） to the wild-type cotton ovule culture significantly suppressed fiber growth, respectively. Their inhibitory effects were caused by the reduction of superoxide radical （O2^-）. Ten GhPOX genes （cDNAs） encoding cotton class III peroxidases were isolated, among them eight GhPOX genes were reported for the first time. Microarray analyses indicated that GhPOX1 was the mostly predominantly expressed in fast-elongating cotton fiber cells. Real-time quantitative PCR analysis revealed the transcript level of GhPOX1 was over 400-fold higher in growing fiber cells than in ovules, flowers, roots, stems and leaves. To reveal the role of GhPOX1 in plant development, its Arabidopsis orthologue atpox13 mutant was demonstrated to be defective in branch root development. Taken together, the data suggest that GhPOX1 plays an important role during fiber cell elongation possibly by mediating production of reactive oxygen species.
文摘N-acetylglucosaminyltransferase V （GnT-V） is an important tumorigenesis and metastasis-associated enzyme. To study its biofunction, the GnT-V stably suppressed cell line （GnT-V-AS/7721） was constructed from 7721 hepatocarcinoma cells in previous study. In this study, cDNA array gene expression profiles were compared between GnT-V-AS/7721 and parental 7721 cells. The data indicated that GnT-V-AS/7721 showed a characteristic expression pattern consistent with the ER stress. The molecular mechanism of the ER stress was explored in GnT-V-AS/7721 by the analysis on key molecules in both two unfolded protein response （UPR） pathways. For ATF6 and Irel/XBP-1 pathway, it was evidenced by the up-regulation of BIP at mRNA and protein level, and the appearance of the spliced form ofXBP-1. As for PERK/eIF2α pathway, the activation of ER eIF2α kinase PERK was observed. To confirm the results from GriT-V-AS/7721 cells, the key molecules in the UPR were examined again in 7721 cells interfered with the GnT-V by the specific RNAi treatment. The results were similar with those from GnT-V-AS/7721, indicating that blocking of GnT-V can specifically activate ER stress in 7721 cells. Rate of 3H-Man incorporation corrected with rate of 3H-Leu incorporation in GnT-V-AS/7721 was down-regulated greatly compared with the control, which demonstrated the deficient function of the enzyme synthesizing N-glycans after GnT-V blocking. Moreover, the faster migrating form of chaperone GRP94 associated with the underglycosylation, and the extensively changed N-glycans structures of intracellular glycoproteins were also detected in GnT-V-AS/7721. These results supported the mechanism that blocking of GnT-V expression impaired functions of chaperones and N-glycan-synthesizing enzymes, which caused UPR in vivo.
基金supported by research grants from the Diagnosis of Infectious Pathogens and Combination of Diagnostic Technologies (2008ZX10004-002)Prevention and Control of Major Infectious Disease such as AIDS and Viral Hepatitis,State Eleventh Five-Year Plan
文摘Objective To prepare monoclonal antibodies against a newly discovered and conserved linear epitope of Rabies virus nucleoprotein and to use them in a rabies diagnostic test. Methods Synthetic peptide containing the epitope was used as immunogen to prepare hybridoma cell lines by classical hybridoma technology. Anti-peptide monoclonal antibodies produced in ascites of inoculated Balb/c mice were labeled with fluorescein isothiocyanate （FITC） after purification and used in fluorescent antibody test （FAT）. Results Two positive hybridoma cell lines, RVNP-mAbl-CL and RVNP-mAb2-CL, were obtained. RVNP- mAbl-CL produced a higher concentration of monoclonal antibody RVNP-mAbl in Balb/c ascites. FITC-labeled RVNP-mAbl showed correct results on certain Rabies virus-positive canine brain tissue samples and cells of a small subclone of baby hamster kidney 21 cell line （BSR）. Conclusion FITC-labeled RVNP-mAbl has potential application for laboratory diagnosis of rabies
基金the Ministry of Science and Technology,Vietnam for financial support
文摘Objective: To evaluate the impact of plant growth regulators including kinetin(KN),benzyl adenine and naphthalene acetic acid, yeast extract and casein hydrolyzate on biomass accumulation of Vietnamese ginseng Panax vietnamensis(P. vietnamensis) in cell suspension culture.Methods: Cell suspension cultures were established from friable calluses derived from leaves and petioles of 3-year-old in-vitro P. vietnamensis plants. The cell suspension cultures were grown in Murashige and Skoog basal media supplemented with various concentrations of KN, benzyl adenine, naphthalene acetic acid, and yeast extract and casein hydrolyzate.Results: All tested factors generated an increase in the cell biomass of P. vietnamensis in suspension culture, but the impact of each varies depended on the factor type, concentration, and incubation period. Addition of 2.0 mg/L KN resulted in the largest biomass increase after 24 d,(57.0 ± 0.9) and(3.1 ± 0.1) mg/m L fresh and dry weight, respectively,whereas addition of benzyl adenine or naphthalene acetic acid produced optimum levels of Panax cell biomass at 1.0 and 1.5 mg/L, respectively. Addition of the elicitor yeast extract led to a 1.4–2.4 fold increase in biomass of P. vietnamensis, while addition of casein hydrolyzate enhanced biomass accumulation 1.8–2.6 fold.Conclusions: The addition of each factor causes significant changes in biomass accumulation of P. vietnamensis. The largest biomass accumulation is from cultures grown in MS media containing 2.0 mg/L KN for 24 d. The outcome of the present study provides new insights into the optimal suspension culture conditions for studies on the in vitro cell biomass production of P. vietnamensis.
基金supported in part by the grants from the National Basic Research Program of China (Nos.MOST945300 and MOST944500 to TPZ)the National Natural Science Foundation of China (No.31172173 to TPZ)
文摘Comprehending the diversity of the regenerative potential across metazoan phylogeny represents a fundamental challenge in biology. Invertebrates like Hydra and planarians exhibit amazing feats of regeneration, in which an entire organism can be restored t^om minute body segments. Vertebrates like teleost fish and amphibians can also regrow large sections of the body. While this regenerative capacity is greatly attenuated in mammals, there are portions of major organs that remain regenerative. Regardless of the extent, there are common basic strategies to regeneration, including activation of adult stem cells and proliferation of differentiated cells. Here, we discuss the cellular features and molecular mechanisms that are involved in regeneration in different model organisms, including 14ydra, planarians, zebrafish and newts as well as in several mammalian organs.
基金We thank Dr Yue Jun from Institute of Genetics at Fudan University for kind help and advice on 2-DE technique,Hasan Koc from the proteomic center at the Pennsylvania State University for help with protein identification with MS and Qing Zhang for assistance with the normalization of the microarray data.This work was supported by the Youth Exploration Funding of School of Life Sciences at Fudan Universityin part by a grant to H.M.from the US National Science Foundation(MCB-0092075).
文摘The ASK1 （ARABIDOPSIS SKP1-LIKE） protein is a critical component of the SCF （Skpl-Cullin-F box protein） ubiquitin ligase complexes that recruit target proteins for degradation by the 26S proteosome. To investigate proteins that are affected by the ASK1-mediated proteolysis pathway in Arabidopsis flowers, we compared the proteomes of the Arabidopsis wild type and ask1 mutant flower buds using two-dimensional electrophoresis （2-DE）. Ten protein spots with higher or lower abundance in the ask1 mutant flowers compared to wild type flowers were excised and subjected to further mass spectrometry （MS） analysis. The results showed that they were proteins involved in photomorphogenesis, circadian oscillation, post-translation process, stress-responses and cell expansion or elongation, suggesting that those processes were affected in the ask1 mutant. The transcript levels of these genes were also compared based on the Affymetrix gene chip microarray data. No significant difference was observed for most of the genes, suggesting that the proteins with elevated levels of accumulation in the ask1 mutant could be candidate targets regulated by an ASK 1-mediated proteolysis pathway. These results help to elucidate the pleiotropic functions of ASK1 in Arabidopsis developmental processes and also demonstrate the importance and necessity of studying protein levels with respect to gene functions.
基金supported by a grant from the Chinese National Natural Science Foundation(Nos.30270682 and 30770211)to X.Wangsupported in part by a Monsanto Fellowship to the Peking-Yale Joint Center,USA
文摘The COP9 signalosome （CSN） is a multiprotein complex which participates in diverse cellular and developmental processes. CSN1, one of the subunits of CSN, is essential for assembly of the multiprotein complex via PCI （proteasome, COP9 signalosome and initiation factor 3） domain in the C-terminal half of CSN 1. However, the role of the N-terminal domain （NTD） of CSN 1, which is critical for the function of CSN, is not completely understood. Using a yeast two-hybrid （Y2H） screen, we found that the NTD of CSN1 interacts with TSK-associating protein 1 （TSA1）, a reported CaZ＋-binding protein. The interaction between CSN1 and TSA1 was confirmed by co-immunoprecipitation in Arabidopsis. tsal mutants exhibited a short hypocotyl phenotype in darkness but were similar to wild-type Arabidopsis under white light, which suggested that TSA1 might regulate Arabidopsis hypocotyl development in the dark. Furthermore, the expression of TSA1 was significantly lower in a csnl null mutant （fus6）, while CSN1 expression did not change in a tsal mutant with weak TSAI expression. Together, these findings suggest a functional relationship between TSAI and CSN1 in seedling development.
基金Fundings supported by grants from the National Key Research and Development Program of China(Grant No.2017YFA0103902,2018YFA0800300,2019YFA0801900,2019YFA0111400)National Natural Science Foundation of China(Grant No.31771283,91749104,31971074)+3 种基金the Fundamental Research Funds for the Central Universities of Tongji University(No.22120190210)Innovative Research Team of High-Level Local Universities in Shanghai(No.SSMUZDCX20180700)Key Laboratory Program of the Education Commission of Shanghai Municipality(No.DSYS14005)the Science and Technology Innovation Action Plan of Shanghai Science and Technology Committee(No.18140901300).
文摘Melanocortin 4 receptor(MC4R),the most important monogenetic cause of human metabolic disorders,has been of great interest to many researchers in the field of energy homeostasis and public health.Because MC4R is a vital pharmaceutical target for maintaining controllable appetite and body weight for professional athletes,previous studies have mainly focused on the central,rather than the peripheral,roles of MC4R.Thus,the local expression of MC4R and its behavioral regulation remain unclear.In an attempt to shed light on different directions for future studies of MC4R signaling,we review a series of recent and important studies exploring the peripheral functions of MC4R and the direct physiological interaction between peripheral organs and central MC4R neurons in this article.
基金the grant from National Natural Science Foundation of China(81871778)Guangdong Provincial Science and Technology Collaborative Innovation Center for Sport Science(2019B110210004)the key project of Sport Research Foundation of Guangdong Province(GDSS2022M005).
文摘Osteoporosis(OP),a systemic and chronic bone disease,is distinguished by low bone mass and destruction of bone microarchitecture.Ginsenoside Compound-K(CK),one of the metabolites of ginsenoside Rb1,has anti-aging,anti-inflammatory,anti-cancer,and hypolipidemic activities.We have demonstrated CK could promote osteogenesis and fracture healing in our previous study.However,the contribution of CK to osteoporosis has not been examined.In the present study,we investigated the effect of CK on osteoclastogenesis and ovariectomy(OVX)-induced osteoporosis.The results showed that CK inhibited receptor activator for nuclear factor-κB ligand(RANKL)-mediated osteoclast differentiation and reactive oxygen species(ROS)activity by inhibiting the phosphorylation of NF-κB p65 and oxidative stress in RAW264.7 cells.In addition,we also demonstrated that CK could inhibit bone resorption using bone marrow-derived macrophages.Furthermore,we demonstrated that CK attenuated bone loss by suppressing the activity of osteoclast and alleviating oxidative stress in vivo.Taken together,these results showed CK could inhibit osteoclastogenesis and prevent OVX-induced bone loss by inhibiting NF-κB signaling pathway.
基金approved by the Research Ethics Committees of Zhejiang Provincial People’s Hospital(No.QT2022387).
文摘Pancreatic cancer is among the most malignant cancers,and thus early intervention is the key to better survival outcomes.However,no methods have been derived that can reliably identify early precursors of development into malignancy.Therefore,it is urgent to discover early molecular changes during pancreatic tumorigenesis.As aberrant glycosylation is closely associated with cancer progression,numerous efforts have been made to mine glycosylation changes as biomarkers for diagnosis;however,detailed glycoproteomic information,especially site-specific N-glycosylation changes in pancreatic cancer with and without drug treatment,needs to be further explored.Herein,we used comprehensive solid-phase chemoenzymatic glycoproteomics to analyze glycans,glycosites,and intact glycopeptides in pancreatic cancer cells and patient sera.The profiling of N-glycans in cancer cells revealed an increase in the secreted glycoproteins from the primary tumor of MIA PaCa-2 cells,whereas human sera,which contain many secreted glycoproteins,had significant changes of glycans at their specific glycosites.These results indicated the potential role for tumor-specific glycosylation as disease biomarkers.We also found that AMG-510,a small molecule inhibitor against Kirsten rat sarcoma viral oncogene homolog(KRAS)G12C mutation,profoundly reduced the glycosylation level in MIA PaCa-2 cells,suggesting that KRAS plays a role in the cellular glycosylation process,and thus glycosylation inhibition contributes to the anti-tumor effect of AMG-510.
基金supported by the National Key R&D Program of China (2020YFA0803800)the National Natural Science Foundation of China (31971097)。
文摘Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensive systematic search was conducted in PubMed, Web of Science, SPORTDiscus, Cochrane Library electronic databases, and other sources before April 5, 2021. Fourteen studies were included in the systematic review, involving 855 athletes and 521 control subjects. Serum magnesium concentration was significantly lower in athletes(mean difference(MD):-0.04 mmol/L;95% confidence interval(CI):-0.06 to-0.01;P = 0.02)in spite of significantly higher dietary magnesium intake(MD: 51.72 mg/day;95% CI: 14.62 to 88.83;P = 0.006). Meta-analysis showed that 24-h urinary magnesium excretion in athletes was significantly higher than that in the untrained population(MD: 0.76 mmol/day;95% CI: 0.11 to 1.41;P = 0.02). Despite higher total dietary magnesium intake, athletes generally have lower serum magnesium concentration and higher 24-h urinary magnesium excretion, demonstrating that the magnesium requirement of athletes is higher than the untrained population. It is necessary to carry out a dietary assessment and nutrition counseling to help athletes adopt proper diets to meet their nutritional needs in exercise.
基金supported by High Technology Research and Development Center,Ministry of Science and Technology of the People’s Republic of China(2019YFA0801900)the Interdisciplinary Program of Shanghai Jiao Tong University(YG2023QNB22)+2 种基金Epilepsy Research Fund of China Association Against Epilepsy(CJ-B-2021-21)the National Natural Science Foundation of China(NSFC)(No.22122702)Beijing National Laboratory for Molecular Sciences(BNLMS202306).
文摘Although the compositional alterations of gut bacteria in ketogenic diet(KD)have been intensively investigated,the causal relationship between this extreme diet and the microbiota changes is not fully understood.Here,we studied the growth dynamics of intestinal bacteria in KD.We used the CoPTR method to calculate the peak-to-trough ratio(PTR)based on metagenomic sequencing data,serving as an indicator of bacterial growth rates.Notably,Akkermansia muciniphila,a bacterium strongly linked to the therapeutic benefits of KD,exhibited one of the highest growth rates,aligning with its markedly elevated abundance.Our findings also revealed discrepancies in the change patterns of CoPTR values and relative abundances for various bacteria across different diet groups,some of which might be attributed to the exceptionally high or low growth rates of specific species.For some of the species demonstrating obvious differences in growth rates between KD and standard diet,we conducted in vitro culture experiments,supplementing them with diverse nutritional sources to elucidate the underlying mechanisms.The integrative analysis of bacterial abundance and growth dynamics can help deepen our understanding of the gut microbiota changes caused by KD and the therapeutic effects of this special diet.
基金This work was supported by Grant 2015CB910200 from the National Key Basic Research Foundation of China （to X.W.）, Grants 31430046 （to X.W.） and 31401032 （to H,W.） of the National Natural Science Foundation of China, and the Fund 2014RC002 （to X.W.）, 2662015PY0202 （to X.W.）, and 2662014PY068 and 2662017PY122 （to H.W.） of Huazhong Agricultural University,
文摘Abscisic acid （ABA） and brassinosteroid （BR） antagonistically regulate many aspects of plant growth and development. Previous physiological studies have revealed that the inhibition of BR signaling by ABA is largely dependent on ABI1 and ABI2. However, the genetic and molecular basis of how ABI1 and ABI2 are involved in inhibiting BR signaling remains unclear. Although it is known that in the BR signaling pathway the ABA-BR crosstalk occurs in the downstream of BR receptor complex but upstream of BIN2 kinase, a negative regulator of BR signaling, the component that acts as the hub to directly mediate their crosstalk remains a big mystery. Here, we found that ABI1 and ABI2 interact with and dephosphorylate BIN2 to regu- late its activity toward the phosphorylation of BESl. Byin vitro mimicking ABA signal transduction, we found that ABA can promote BIN2 phosphorylation by inhibiting ABI2 through ABA receptors. RNA-sequencing analysis further demonstrated that ABA inhibits BR signaling through the ABA primary signaling components, including its receptors and ABI2, and that ABA and GSK3s co-regulate a common set of stress- responsive genes. Because BIN2 can interact with and phosphorylate SnRK2s to activate its kinase activity, our study also reveals there is a module of PP2Cs--BIN2-SnRK2s in the ABA signaling pathway. Collectively, these findings provide significant insights into how plants balance growth and survival by coordinately regu- lating the growth-promoting signaling pathway and stress responses under abiotic stresses.
基金supported by basic grants from CONACYT–Mexico to AT and LDa scholarship to ORS(Grant No.347589/237183)
文摘Protein size is an important biochemical feature since longer proteins can harbor more domains and therefore can display more biological functionalities than shorter proteins. We found remarkable differences in protein length, exon structure, and domain count among different phylo- genetic lineages. While eukaryotic proteins have an average size of 472 amino acid residues （aa）, average protein sizes in plant genomes are smaller than those of animals and fungi. Proteins unique to plants are -81 aa shorter than plant proteins conserved among other eukaryotic lineages. The smaller average size of plant proteins could neither be explained by endosymbiosis nor subcellular compartmentation nor exon size, but rather due to exon number. Metazoan proteins are encoded on average by -10 exons of small size [-176 nucleotides （nt）]. Streptophyta have on average only -5.7 exons of medium size （-230 nt）. Multicellular species code for large proteins by increasing the exon number, while most unicellular organisms employ rather larger exons （ 〉 400 nt）. Among subcellular compartments, membrane proteins are the largest （-520 aa）, whereas the smallest proteins correspond to the gene ontology group of ribosome （-240 aa）. Plant genes are encoded by half the number of exons and also contain fewer domains than animal proteins on average. Interestingly, endosymbiotic proteins that migrated to the plant nucleus became larger than their cyanobacterial orthologs. We thus conclude that plants have proteins larger than bacteria but smaller than animals or fungi. Compared to the average of eukaryotic species, plants have -34% more but -20% smaller proteins. This suggests that photosynthetic organisms are unique and deserve therefore special attention with regard to the evolutionary forces acting on their genomes and proteomes.
基金Supported by the National Natural Science Foundation of China （39870452）.
文摘Chlorophyllase （EC 3.1.1.14） is involved in the first step of chlorophyll degradation. Isolation of chlorophyllase genes greatly facilitates characterization of chlorophyllase properties and elucidation of molecular regulation of their in vivo activities. There are two chlorophyllase genes, AtCLH1 and AtCLH2, in Arabidopsis thaliana. The in vivo roles of AtCLH1 have been reported previously. However, few studies have been carried out on AtCLH2. Here, we show that purified recombinant Chlase2, encoded by AtCLH2, exhibits in vitro chlorophyllase activity. Interestingly, ＂activation＂ of in vitro activity of the recombinant Chlase2 required higher concentrations of a detergent or a polar solvent. To determine its activity in vivo, the expression of AtCLH2 was inhibited by RNA interference. RNAi plants showed decreased contents of chlorophyllide without a substantial change in the total amount of the extractable chlorophyll and consequently presented lower chlorophyllide to chlorophyll ratios in their leaves. In addition, the two AtCLHs exhibited differential expression patterns. Our results suggest that AtCLH2 might play a distinctive role in chlorophyll catabolism in vivo.
文摘Hundreds of leucine-rich repeat receptor-like kinases （LRR-RLKs） play indispensable roles in a wide range of plant developmental and physiological processes. The mechanisms controlling LRR-RLKs at a basal and inactive status are essential but rarely studied. BKI1 is the only reported inhibitor of receptor kinases in Arabidopsis, which negatively regulates BRI1 in the brassinosteroid pathway. In this study, we found that BKI1 can also interact with another important LRR-RLK, ERECTA （ER）. Phenotypic analysis showed that BKI1 and ER together regulate plant architecture, including pedicel orientation, which is a newly reported phenotype in the BR- and ER-mediated developmental processes. Gene expression analysis revealed that BKI1 regulates a subset of ER-responsive genes. Kinase assays demonstrated that BKI1 inhibits ER kinase activity. In addition, the release of BKI1 inhibition on ER signaling relies largely on BRI1 activation. Our data provide significant insights into the regulation and activation of RLKs and suggest that BKI1 functions as a common suppressor of the BRI1 and ER signaling pathways.
文摘Unlike animals, plants do not set aside germ cells early in development. In angiosperm species, reproduction occurs in the adult plant upon flowering. The multicellular male and female gametophytes differentiate from meiotic products within reproductive floral organs. Double fertilization is another remarkable feature of most angiosperm species. The zygote derived from fertilization of the egg cell by one of the sperm cells and the endosperm from fertilization of the central cell by the second sperm cell develop in a coordinated manner together and enclosed in the sporophytic maternal integuments, forming the seed. Understanding plant reproduction is biologically pertinent and agronomically and ecologically important. Here, we describe the known functions of histone lysine methylations in various steps of reproduction in the reference plant Arabidopsis thaliana. It is emerging that histone lysine methylation is key for understanding epigenetic regulation networks of genome function.
基金supported by grants to X.G. from the National Natural Science Foundation of China(31170169 and 31070232)
文摘Root organogenesis involves cell division, differentiation and expansion. The molecular mechanisms regulating root development are not fully understood. In this study, we identified poly（adenosine diphosphate （ADP）-ribose） polymerases （PARPs） as new players in root development. PARP catalyzes poly（ADP-ribosyl）ation of proteins by repeatedly adding ADP-ribose units onto proteins using nicotinamide adenine dinucleotide （NAD ） as the donor. We found that inhibition of PARP activities by 3-aminobenzomide （3-AB） increased the growth rates of both primary and lateral roots, leading to a more developed root system. The double mutant of Arabidopsis PARPs, parplparp2, showed more rapid primary and lateral root growth. Cyclin genes regulating G1-to-S and G2-to-M transition were up-regulated upon treatment by 3-AB. The proportion of 2C ceils increased while cells with higher DNA ploidy declined in the roots of treated plants, resulting in an enlarged root meristematic zone. The expression level of PARP2 was very low in the meristematic zone but high in the maturation zone, consistent with a role of PARP in inhibiting mitosis and promoting cell differentiation. Our results suggest that PARPs play an important role in root development by negatively regulating root cell division.
基金supported by the Shanghai Science and Technology Innovation Action Plan 18JC1411800the National Natural Science Foundation of China(grant nos.31770274 and 31970343).
文摘In modern agriculture,frequent application of herbicides may induce the evolution of resistance in plants,but the mechanisms underlying herbicide resistance remain largely unexplored.Here,we report the char-acterization of rtp 1(resistant to paraquat 1),an Arabidopsis mutant showing strong resistance to the widely used herbicides paraquat and diquat.The rtp1 mutant is semi-dominant and carries a point mutation in the gene encoding the multidrug and toxic compound extrusion family protein DTX6,leading to the change of glycine to glutamic acid at residue 311(G311E).The wild-type DTX6 with glycine 311 conferred weak para-quat and diquat resistance when overexpressed,while mutation of glycine 311 to a negatively charged amino acid(G311E or G311D)markedly increased the paraquat and diquat resistance of plants,whereas mutation to a positively charged amino acid(G311R or G311K)compromised the resistance,suggesting that the charge property of residue 311 of DTX6 is critical for the paraquat and diquat resistance of Arabi-dopsis plants.DTX6 is localized in the endomembrane trafficking system and may undergo the endosomal sorting to localize to the vacuole and plasma membrane.Treatment with the V-ATPase inhibitor ConA reduced the paraquat resistance of the rtp1 mutant.Paraquat release and uptake assays demonstrated that DTX6 is involved in both exocytosis and vacuolar sequestration of paraquat.DTX6 and DTX5 show functional redundancy as the dtx5 dtx6 double mutant but not the dtx6 single mutant plants were more sen-sitive to paraquat and diquat than the wild-type plants.Collectively,our work reveals a potential mecha-nism for the evolution of herbicide resistance in weeds and provides a promising gene for the manipulation of plant herbicide resistance.
基金This work was supported by the National Key R&D Program of China(NO.2016YFC1303503)the Key Biomedical Program of Shanghai(NO.17431902200 and 18431902600)the Open Research Fund of State Key Laboratory of Genetic Engineering of Fudan University(NO.SKLGE1816).
文摘The discrepancy of indoleamine 2,3-dioxygenase 1(IDO1)function in atherosclerosis has been noted.Compared to the protective effect of IDO1 against established atherogenesis,the role of IDO1 in the developmental process of atherosclerosis is still unclear.Here,the expression patterns and activities of IDO1 and its isoenzyme tryptophan 2,3-dioxygenase(TDO)in aortas and blood samples of patients with atherosclerosis were investigated.IDO1 and TDO were colocalized with CD3-positive lymphocytes and CD68-positive macrophages in atherosclerotic lesions.The expression and activity of IDO1 and TDO increased with the grade of the histological classification in early atherosclerosis(grade I,II),but the increase did not continue in advanced atherosclerosis(grade III).Treatment of THP-1 macrophages(THP-M)with oxidized low-density lipoprotein(oxLDL)induced the expression of IDO1 via the PI3K/Akt/NF-κB pathway,indicating the potential function of IDO1 in foam cells.Before and after treatment with oxLDL on THP-M,IFN-γ-induced IDO1 exhibited different degrees of promotion on foaming,inflammatory factor production and cell apoptosis.Finally,we found that the IDO1 inhibitor 1-methyl-tryptophan could elevate the high-density lipoprotein cholesterol level in serum and reduce the area of the aortic atherosclerotic lesions in high-fat diet-fed ApoE−/−mice.Our study indicated that IDO1 played a complicated and unfixed role in the entire process of atherogenesis,despite the atheroprotective role in established atherosclerosis.IDO1 also had proatherosclerotic functions in the developmental stages of atherosclerosis.Modulation of IDO1 could be a good method for alleviating atherosclerosis.
