Effect of mutations on acetohydroxyacid synthase(AHAS)function in Cyperus difformis L.

Cyperus difformis L.is a troublesome weed in paddy fields and has attracted attention due to its resistance to acetohydroxyacid synthase(AHAS)inhibitors.It was found that the amino acid mutation in AHAS was the primary cause for the resistance of Cyperus difformis.However,the effect of different mutations on AHAS function is not clear in Cyperus difformis.To confirm the effect of mutations on AHAS function,six biotypes were collected,including Pro197Arg,Pro197Ser,Pro197Leu,Asp376Glu,Trp574Leu and wild type,from Hunan,Anhui,Jiangxi and Jiangsu provinces,China and the function of AHAS was characterized.The AHAS in vitro inhibition assay results indicated that the mutations decreased the sensitivity of AHAS to pyrazosulfuron-ethyl,in which the I_(50)(the half maximal inhibitory concentration)of wild type AHAS was 0.04μmol L^(-1)and Asp376Glu,Pro197Leu,Pro197Arg,Pro197Ser and Trp574Leu mutations were 3.98,11.50,40.38,38.19 and 311.43μmol L^(-1),respectively.In the determination of enzyme kinetics parameters,the Km and the maximum reaction velocity(Vmax)of the wild type were 5.18 mmol L^(-1)and 0.12 nmol mg^(-1)min^(-1),respectively,and the Km values of AHAS with Asp376Glu,Trp574Leu,Pro197Leu and Pro197Ser mutations were 0.38-0.93 times of the wild type.The Km value of the Pro197Arg mutation was 1.14times of the wild type,and the Vmax values of the five mutations were 1.17-3.33-fold compared to the wild type.It was found that the mutations increased the affinity of AHAS to the substrate,except for the Pro197Arg mutation.At a concentration of 0.0032-100 mmol L^(-1)branched-chain amino acids(BCAAs),the sensitivity of the other four mutant AHAS biotypes to feedback inhibition decreased,except for the Pro197Arg mutation.This study elucidated the effect of different mutations on AHAS function in Cyperus difformis and provided ideas for further study of resistance development.

Phytoene synthases 1 modulates tomato fruit quality through influencing the metabolic flux between carotenoid and flavonoid pathways

The deterioration in fruit quality of commercial tomatoes is a major concern of modern tomato breeding.However,the metabolism and genetics of fruit quality are poorly understood.Here,we performed transgenic and molecular biology experiments to reveal that tomato phytoene synthase 1(SlPSY1)is responsible for the accumulation of an important flavor chemical,6-methyl-5-hepten-2-one(MHO).To dissect the function of SlPSY1 in regulating fruit quality,we generated and analyzed a dataset encompassing over 2000 compounds detected by GC-MS and LC-MS/MS along with transcriptomic data.The combined results illustrated that SlPSY1 deficiency imparts novel flavor to yellow tomatoes with 236 volatiles significantly changed and improves fruit firmness,possibly due to accumulation of seven cutins.Further analysis indicated SlPSY1 is essential for carotenoid-derived metabolite biosynthesis by catalyzing prephytoene-PP(PPPP)to 15-cis-phytoene.Notably,we showed that SlPSY1 can influence the metabolic flux between carotenoid and flavonoid pathways,and this metabolic flux was confirmed by silencing SlCHS1.Our study provided insights into the multiple effects of SlPSY1 on tomato fruit metabolome and highlights the potential to produce high-quality fruit by rational design of SlPSY1 expression.

Enhancing the radiosensitivity of colorectal cancer cells by reducing spermine synthase through promoting autophagy and DNA damage

BACKGROUND Colorectal cancer(CRC),the third most common cancer worldwide,has increasingly detrimental effects on human health.Radiotherapy resistance diminishes treatment efficacy.Studies suggest that spermine synthase(SMS)may serve as a potential target to enhance the radiosensitivity.AIM To investigate the association between SMS and radiosensitivity in CRC cells,along with a detailed elucidation of the underlying mechanisms.METHODS Western blot was adopted to assess SMS expression in normal colonic epithelial cells and CRC cell lines.HCT116 cells were transfected with control/SMS-specific shRNA or control/pcDNA3.1-SMS plasmids.Assessments included cell viability,colony formation,and apoptosis via MTT assays,colony formation assays,and flow cytometry.Radiosensitivity was studied in SMS-specific shRNA-transfected HCT116 cells post-4 Gy radiation,evaluating cell viability,colony formation,apoptosis,DNA damage(comet assays),autophagy(immunofluorescence),and mammalian target of rapamycin(mTOR)pathway protein expression(western blot).RESULTS Significant up-regulation of SMS expression levels was observed in the CRC cell lines.Upon down-regulation of SMS expression,cellular viability and colonyforming ability were markedly suppressed,concomitant with a notable increase in apoptotic indices.Furthermore,attenuation of SMS expression significantly augmented the sensitivity of HCT116 cells to radiation therapy,evidenced by a pronounced elevation in levels of cellular DNA damage and autophagy.Impor tantly,down-regulation of SMS corresponded with a marked reduction in the expression levels of proteins associated with the mTOR signaling pathway.CONCLUSION Knocking down SMS attenuates the mTOR signaling pathway,thereby promoting cellular autophagy and DNA damage to enhance the radiosensitivity of CRC cells.

The gene encoding flavonol synthase contributes to lesion mimic in wheat

Lesion mimic often exhibits leaf disease-like symptoms even in the absence of pathogen infection,and is characterized by a hypersensitive-response(HR)that closely linked to plant disease resistance.Despite this,only a few lesion mimic genes have been identified in wheat.In this investigation,a lesion mimic wheat mutant named je0297 was discovered,showing no alteration in yield components when compared to the wild type(WT).Segregation ratio analysis of the F_(2)individuals resulting from the cross between the WT and the mutant revealed that the lesion mimic was governed by a single recessive gene in je0297.Using Bulked segregant analysis(BSA)and exome capture sequencing,we mapped the lesion mimic gene designated as lm6 to chromosome 6BL.Further gene fine mapping using 3315 F_(2)individuals delimited the lm6 within a 1.18 Mb region.Within this region,we identified 16 high-confidence genes,with only two displaying mutations in je0297.Notably,one of the two genes,responsible for encoding flavonol synthase,exhibited altered expression levels.Subsequent phenotype analysis of TILLING mutants confirmed that the gene encoding flavonol synthase was indeed the causal gene for lm6.Transcriptome sequencing analysis revealed that the DEGs between the WT and mutant were significantly enriched in KEGG pathways related to flavonoid biosynthesis,including flavone and flavonol biosynthesis,isoflavonoid biosynthesis,and flavonoid biosynthesis pathways.Furthermore,more than 30 pathogen infection-related(PR)genes exhibited upregulation in the mutant.Corresponding to this expression pattern,the flavonoid content in je0297 showed a significant decrease in the 4^(th)leaf,accompanied by a notable accumulation of reactive oxygen,which likely contributed to the development of lesion mimic in the mutant.This investigation enhances our comprehension of cell death signaling pathways and provides a valuable gene resource for the breeding of disease-resistant wheat.

Inhibiting ceramide synthase 5 expression in microglia decreases neuroinflammation after spinal cord injury

Microglia,the resident monocyte of the central nervous system,play a crucial role in the response to spinal cord injury.However,the precise mechanism remains unclear.To investigate the molecular mechanisms by which microglia regulate the neuroinflammatory response to spinal cord injury,we performed single-cell RNA sequencing dataset analysis,focusing on changes in microglial subpopulations.We found that the MG1 subpopulation emerged in the acute/subacute phase of spinal cord injury and expressed genes related to cell pyroptosis,sphingomyelin metabolism,and neuroinflammation at high levels.Subsequently,we established a mouse model of contusive injury and performed intrathecal injection of siRNA and molecular inhibitors to validate the role of ceramide synthase 5 in the neuroinflammatory responses and pyroptosis after spinal cord injury.Finally,we established a PC12-BV2 cell co-culture system and found that ceramide synthase 5 and pyroptosis-associated proteins were highly expressed to induce the apoptosis of neuron cells.Inhibiting ceramide synthase 5 expression in a mouse model of spinal cord injury effectively reduced pyroptosis.Furthermore,ceramide synthase 5-induced pyroptosis was dependent on activation of the NLRP3 signaling pathway.Inhibiting ceramide synthase 5 expression in microglia in vivo reduced neuronal apoptosis and promoted recovery of neurological function.Pla2g7 formed a“bridge”between sphingolipid metabolism and ceramide synthase 5-mediated cell death by inhibiting the NLRP3 signaling pathway.Collectively,these findings suggest that inhibiting ceramide synthase 5 expression in microglia after spinal cord injury effectively suppressed microglial pyroptosis mediated by NLRP3,thereby exerting neuroprotective effects.

Genome-wide identification and function analysis of the sucrose phosphate synthase MdSPS gene family in apple

Sucrose phosphate synthase(SPS)is a rate-limiting enzyme that works in conjunction with sucrose-6-phosphate phosphatase(SPP)for sucrose synthesis,and it plays an essential role in energy provisioning during growth and development in plants as well as improving fruit quality.However,studies on the systematic analysis and evolutionary pattern of the SPS gene family in apple are still lacking.In the present study,a total of seven MdSPS and four MdSPP genes were identified from the Malus domestica genome GDDH13 v1.1.The gene structures and their promoter cis-elements,protein conserved motifs,subcellular localizations,physiological functions and biochemical properties were analyzed.A chromosomal location and gene-duplication analysis demonstrated that whole-genome duplication(WGD)and segmental duplication played vital roles in MdSPS gene family expansion.The Ka/Ks ratio of pairwise MdSPS genes indicated that the members of this family have undergone strong purifying selection during domestication.Furthermore,three SPS gene subfamilies were classified based on phylogenetic relationships,and old gene duplications and significantly divergent evolutionary rates were observed among the SPS gene subfamilies.In addition,a major gene related to sucrose accumulation(MdSPSA2.3)was identified according to the highly consistent trends in the changes of its expression in four apple varieties(‘Golden Delicious’,‘Fuji’,‘Qinguan’and‘Honeycrisp’)and the correlation between gene expression and soluble sugar content during fruit development.Furthermore,the virus-induced silencing of MdSPSA2.3 confirmed its function in sucrose accumulation in apple fruit.The present study lays a theoretical foundation for better clarifying the biological functions of the MdSPS genes during apple fruit development.

Mutations in Plasmodium knowlesi Kelch protein 13 and the dihydropteroate synthase gene in clinical samples

Objective:To determine the genetic diversity,natural selection and mutations in Plasmodium(P.)knowlesi drug resistant molecular markers Kelch 13 and dhps gene in clinical samples of Malaysia.Methods:P.knowlesi full-length gene sequences Kelch 13 gene(PkK13)from 40 samples and dhps gene from 30 samples originating from Malaysian Borneo were retrieved from public databases.Genetic diversity,natural selection,and phylogenetic analysis of gene sequences were analysed using DNAsp v5.10 and MEGA v5.2.Results:Seventy-two single nucleotide polymorphic sites(SNPs)across the full-length PkK13 gene(63 synonymous substitutions and 9 non-synonymous substitutions)with nucleotide diversity ofπ~0.005 was observed.Analysis of the full-length Pkdhps gene revealed 73 SNPs andπ~0.006(44 synonymous substitutions and 29 non-synonymous substitutions).A high number of haplotypes(PkK13;H=37 and Pkdhps;H=29)with haplotype diversity of Hd~0.99 were found in both genes,indicating population expansion.Nine mutant alleles were identified in PkK13 amino acid alignment of which,7(Asp3Glu,Lys50Gln,Lys53Glu,Ser123Thr,Ser127Pro,Ser149Thr and Ala169Thr)were within the Plasmodium specific domain,2(Val372Ile and Lys424Asn)were in the BTB/POZ domain and no mutation was observed within the kelch propeller domain.The 29 non-synonymous mutations in the Pkdhps gene were novel and only presented in exon 1 and 2.Conclusions:Monitoring the mutations from clinical samples collected from all states of Malaysia along with clinical efficacy studies will be necessary to determine the drug resistance in P.knowlesi.

Metformin promotes angiogenesis and functional recovery in aged mice after spinal cord injury by adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway

Treatment with metformin can lead to the recovery of pleiotropic biological activities after spinal cord injury.However,its effect on spinal cord injury in aged mice remains unclear.Considering the essential role of angiogenesis during the regeneration process,we hypothesized that metformin activates the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway in endothelial cells,thereby promoting microvascular regeneration in aged mice after spinal cord injury.In this study,we established young and aged mouse models of contusive spinal cord injury using a modified Allen method.We found that aging hindered the recovery of neurological function and the formation of blood vessels in the spinal cord.Treatment with metformin promoted spinal cord microvascular endothelial cell migration and blood vessel formation in vitro.Furthermore,intraperitoneal injection of metformin in an in vivo model promoted endothelial cell proliferation and increased the density of new blood vessels in the spinal cord,thereby improving neurological function.The role of metformin was reversed by compound C,an adenosine monophosphate-activated protein kinase inhibitor,both in vivo and in vitro,suggesting that the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway likely regulates metformin-mediated angiogenesis after spinal cord injury.These findings suggest that metformin promotes vascular regeneration in the injured spinal cord by activating the adenosine monophosphate-activated protein kinase/endothelial nitric oxide synthase pathway,thereby improving the neurological function of aged mice after spinal cord injury.

Glycogen Synthase Kinase-3β,NLRP3 Inflammasome,and Alzheimer's Disease

Alzheimer’s disease (AD) is the most prevalent cause of dementia worldwide. Because of the progressive neurodegeneration, individual cognitive and behavioral functions are impaired, affecting the quality of life of millions of people. Although the exact pathogenesis of AD has not been fully elucidated, amyloid plaques, neurofibrillary tangles (NFTs), and sustaining neuroinflammation dominate its characteristics. As one of the major tau kinases leading to hyperphosphorylation and aggregation of tau, glycogen synthase kinase-3β (GSK-3β) has been drawing great attention in various AD studies. Another research focus of AD in recent years is the inflammasome, a multiprotein complex acting as a regulator in immunological reactions to exogenous and endogenous danger signals, of which the Nod-like receptor (NLR) family, pyrin domain-containing 3 (NLRP3) inflammasome has been studied mostly in AD and proven to play a significant role in AD development by its activation and downstream effects such as caspase-1 maturation and interleukin (IL)-1β release. Studies have shown that the NLRP3 inflammasome is activated in a GSK-3β-dependent way and that inhibition of the NLRP3 inflammasome downregulates GSK-3β, suggesting that these two important proteins are closely related. This article reviews the respective roles of GSK-3β and the NLRP3 inflammasome in AD as well as their relationship and interaction.

Neuronal nitric oxide synthase/reactive oxygen species pathway is involved in apoptosis and pyroptosis in epilepsy

Dysfunction of neuronal nitric oxide synthase contributes to neurotoxicity,which triggers cell death in various neuropathological diseases,including epilepsy.Studies have shown that inhibition of neuronal nitric oxide synthase activity increases the epilepsy threshold,that is,has an anticonvulsant effect.However,the exact role and potential mechanism of neuronal nitric oxide synthase in seizures are still unclear.In this study,we performed RNA sequencing,functional enrichment analysis,and weighted gene coexpression network analysis of the hippocampus of tremor rats,a rat model of genetic epilepsy.We found damaged hippocampal mitochondria and abnormal succinate dehydrogenase level and Na+-K+-ATPase activity.In addition,we used a pilocarpine-induced N2a cell model to mimic epileptic injury.After application of neuronal nitric oxide synthase inhibitor 7-nitroindazole,changes in malondialdehyde,lactate dehydrogenase and superoxide dismutase,which are associated with oxidative stress,were reversed,and the increase in reactive oxygen species level was reversed by 7-nitroindazole or reactive oxygen species inhibitor N-acetylcysteine.Application of 7-nitroindazole or N-acetylcysteine downregulated the expression of caspase-3 and cytochrome c and reversed the apoptosis of epileptic cells.Furthermore,7-nitroindazole or N-acetylcysteine downregulated the abnormally high expression of NLRP3,gasdermin-D,interleukin-1βand interleukin-18.This indicated that 7-nitroindazole and N-acetylcysteine each reversed epileptic cell death.Taken together,our findings suggest that the neuronal nitric oxide synthase/reactive oxygen species pathway is involved in pyroptosis of epileptic cells,and inhibiting neuronal nitric oxide synthase activity or its induced oxidative stress may play a neuroprotective role in epilepsy.

Prostaglandin F_(2α)synthase promotes oxaliplatin resistance in colorectal cancer through prostaglandin F_(2α)-dependent and F_(2α)-independent mechanism

BACKGROUND Oxaliplatin(Oxa)is the first-line chemotherapy drug for colorectal cancer(CRC),and Oxa resistance is crucial for treatment failure.Prostaglandin F_(2α)synthase(PGF 2α)(PGFS),an enzyme that catalyzes the production of PGF_(2α),is involved in the proliferation and growth of a variety of tumors.However,the role of PGFS in Oxa resistance in CRC remains unclear.AIM To explore the role and related mechanisms of PGFS in mediating Oxa resistance in CRC.METHODS The PGFS expression level was examined in 37 pairs of CRC tissues and paracancerous tissues at both the mRNA and protein levels.Overexpression or knockdown of PGFS was performed in CRC cell lines with acquired Oxa resistance(HCT116-OxR and HCT8-OxR)and their parental cell lines(HCT116 and HCT8)to assess its influence on cell proliferation,chemoresistance,apoptosis,and DNA damage.For determination of the underlying mechanisms,CRC cells were examined for platinum-DNA adducts and reactive oxygen species(ROS)levels in the presence of a PGFS inhibitor or its products.RESULTS Both the protein and mRNA levels of PGFS were increased in the 37 examined CRC tissues compared to the adjacent normal tissues.Oxa induced PGFS expression in the parental HCT116 and HCT8 cells in a dosedependent manner.Furthermore,overexpression of PGFS in parental CRC cells significantly attenuated Oxainduced proliferative suppression,apoptosis,and DNA damage.In contrast,knockdown of PGFS in Oxa-resistant HCT116 and HCT8 cells(HCT116-OxR and HCT8-OxR)accentuated the effect of Oxa treatment in vitro and in vivo.The addition of the PGFS inhibitor indomethacin enhanced the cytotoxicity caused by Oxa.Treatment with the PGFS-catalyzed product PGF_(2α)reversed the effect of PGFS knockdown on Oxa sensitivity.Interestingly,PGFS inhibited the formation of platinum-DNA adducts in a PGF_(2α)-independent manner.PGF_(2α)exerts its protective effect against DNA damage by reducing ROS levels.CONCLUSION PGFS promotes resistance to Oxa in CRC via both PGF_(2α)-dependent and PGF_(2α)-independent mechanisms.

Identifi cation of sesquiterpene synthase genes in the genome of Aquilaria sinensis and characterization of anα-humulene synthase

Sesquiterpenes are the major pharmacodynamic components of agarwood,a precious traditional Chinese medicine obtained from the resinous portions of Aquilaria sinensis trees that form in response to environmental stressors.To characterize the sesquiterpene synthases responsible for sesquiterpene production in A.sinensis,a bioinformatics analysis of the genome of A.sinensis identifi ed six new terpene synthase genes,and 16 sesquiterpene synthase genes were identifi ed as type TPS-a in a phylogenetic analysis.The expression patterns for eight of the sesquiterpene synthase genes after treatment with various hormones or hydrogen peroxide were analyzed by real-time quantitative PCR.The results suggest that 100μM methyl jasmonate,ethephon,(±)-abscisic acid or hydrogen peroxide could be eff ective short-term eff ectors to increase the expression of sesquiterpene synthase genes,while 1 mM methyl salicylate may have long-term eff ects on increasing the expression of specifi c sesquiterpene synthase genes(e.g.,As-SesTPS,AsVS,AsTPS12 and AsTPS29).The expression changes in these genes under various conditions refl ected their specifi c roles during abiotic or biotic stresses.Heterologous expression of a novel A.sinensis sesquiterpene synthase gene,AsTPS2,in Escherichia coli produced a major humulene product,so AsTPS2 is renamed AsHS1.AsHS1 is diff erent from ASS1,AsSesTPS,and AsVS,for mainly producingα-humulene.Based on the predicted space conformation of the AsHS1 model,the small ligand molecule may bind to the free amino acid by hydrogen bonding for the catalytic function of the enzyme,while the substrate farnesyl diphosphate(FPP)probably binds to the free amino acid on one side of the RxR motif.Arg450,Asp453,Asp454,Thr457,and Glu461 from the NSE/DTE motif and D307 and D311 from the DDxxD motif were found to form a polar interaction with two Mg^(2+)clusters by docking.The Mg^(2+)-bound DDxxD and NSE/DTE motifs and the free RXR motif are jointly directed into the catalytic pocket of AsHS1.Comparison of the tertiary structural models of AsHS1 with ASS1 showed that they diff ered in structures in several positions,such as surrounding the secondary catalytic pocket,which may lead to diff erences in catalytic products.Based on the results,biosynthetic pathways for specifi c sesquiterpenes such asα-humulene in A.sinensis are proposed.This study provides novel insights into the functions of the sesquiterpene synthases of A.sinensis and enriches knowledge on agarwood formation.

A nonsynonymous mutation in an acetolactate synthase gene (Gh_D10G1253) is required for tolerance to imidazolinone herbicides in cotton

Background Herbicide tolerance in crops enables them to survive when lethal doses of herbicides are applied to surrounding weeds.Herbicide-tolerant crops can be developed through transgenic approaches or traditional mutagenesis approaches.At present,no transgenic herbicide tolerant cotton have been commercialized in China due to the genetically-modified organism(GMO)regulation law.We aim to develop a non-transgenic herbicide-tolerant cotton through ethyl methanesulfonate(EMS)mutagenesis,offering an alternative choice for weed management.Results Seeds of an elite cotton cultivar Lumianyan 37(Lu37)were treated with EMS,and a mutant Lu37-1 showed strong tolerance to imidazolinone(IMI)herbicides was identified.A novel nonsynonymous substitution mutation Ser642Asn at acetolactate synthase(ALS)(Gh_D10G1253)in Lu37-1 mutant line was found to be the potential cause to the IMI herbicides tolerance in cotton.The Ser642Asn mutation in ALS did not present among the genomes of natural Gossypium species.Cleaved amplified polymorphic sequence(CAPS)markers were developed to identify the ALS mutant allele.The Arabidopsis overexpressing the mutanted ALS also showed high tolerance to IMI herbicides.Conclusion The nonsynonymous substitution mutation Ser642Asn of the ALS gene Gh_D10G1253 is a novel identi-fied mutation in cotton.This substitution mutation has also been identified in the orthologous ALS genes in other crops.This mutant ALS allele can be used to develop IMI herbicide-tolerant crops via a non-transgenic or transgenic approach.

Identification and Pathogen Stimulation Patterns of Neuronal Nitric Oxide Synthase(nNOS)in Black Rockfish(Sebastes schlegelii)

Neuronal nitric oxide synthase(nNOS)was the producer of nitric oxide(NO)which played important gas messenger molecules in biological process.It also can take effect as immune regulation molecule in organism.Black rockfish(Sebastes schlegelii)is an important economic fish which were widely farmed in East Asia countries.Meanwhile,the pathogenic bacteria such as the Edwardsiella tarda and Vibrio anguillarum in seawater always brought serious obstacles to their healthy growth.In order to explore the expression pattern of n NOS gene under the pathogen stimulation and predict its immune function,the n NOS gene in black rockfish named Ssn NOS was identified.It was 3780 bp in length,located on chromosome 6,and contained 27 coding domain sequence(CDs).According to the phylogenetic analysis,the Ssn NOS showed closest relative to the counterpart gene of swamp eel(Monopterus albus).Meanwhile,analysis of Ssn NOS expression in various healthy tissues showed that Ssn NOS expression level was highest in healthy brain tissues,followed by intestinal tissues.In addition,Ssn NOS showed significant expression changes in response to stimulation by two pathogens.Particular in gill,the expression of Ssn NOS after pathogenic stimulation increased significantly.The Elisa analysis showed the Ssn NOS content in gills was much higher than that in other tissues at all time points.Moreover,the expression patterns of Ssn NOS in brain,intestine and kidney after stimulation by pathogens showed a distinct expression pattern which first down-regulated and then up-regulated.Therefore,the Ssn NOS may be an important signaling molecule for fish to respond rapidly in immune stimulation.

ZmMS39 encodes a callose synthase essential for male fertility in maize(Zea mays L.)

Callose contributes to many biological processes of higher plants including pollen development,cell plate and vascular tissue formation,as well as regulating the transport function of plasmodesmata.The functions of callose synthase genes in maize have been little studied.We describe a maize male-sterile mutant 39(ms39)characterized by reduced plant height.In this study,we confirmed using CRISPR/Cas9 technology that a mutation in Zm00001d043909(ZmCals12),encoding a callose synthase,is responsible for the male sterility of the ms39 mutant.Compared with male-fertile plants,callose deposition around the dyads and tetrads in ms39 anthers was significantly reduced.Increased cell autophagy observed in ms39 anthers may have been due to the premature programmed cell death of tapetal cells,leading to collapse of the anther wall structure.Disordered glucose metabolism in ms39 may have intensified autophagy in anthers.Evaluation of the ms39 gene on maize heterosis by paired-crossed experiment with 11 maize inbred lines indicated that ms39 can be used for maize hybrid seed production.

Correlation between the expressions of metastasis-associated factor-1 in colon cancer and vacuolar ATP synthase

BACKGROUND Clinical prognosis often worsens due to high recurrence rates following radical surgery for colon cancer.The examination of high-risk recurrence factors post-surgery provides critical insights for disease evaluation and treatment planning.AIM To explore the relationship between metastasis-associated factor-1 in colon cancer(MACC1)and vacuolar ATP synthase(V-ATPase)expression in colon cancer tissues,and recurrence rate in patients undergoing radical colon cancer surgery.METHODS We selected 104 patients treated with radical colon cancer surgery at our hospital from January 2018 to June 2021.Immunohistochemical staining was utilized to assess the expression levels of MACC1 and V-ATPase in these patients.RESULTS The rates of MACC1 and V-ATPase positivity were 64.42%and 67.31%,respe-ctively,in colon cancer tissues,which were significantly higher than in paracan-cerous tissues(P<0.05).Among patients with TNM stage III,medium to low differentiation,and lymph node metastasis,the positive rates of MACC1 and V-ATPase were significantly elevated in comparison to patients with TNM stage I-II,high differentiation,and no lymph node metastasis(P<0.05).The rate of MACC1 positivity was 76.67%in patients with tumor diameters>5 cm,notably higher than in patients with tumor diameters≤5 cm(P<0.05).We observed a positive correlation between MACC1 and V-ATPase expression(rs=0.797,P<0.05).The positive rates of MACC1 and V-ATPase were significantly higher in patients with recurrence compared to those without(P<0.05).Logistic regression analysis revealed TNM stage,lymph node metastasis,MACC1 expression,and V-ATPase expression as risk factors for postoperative colon cancer recurrence(OR=6.322,3.435,2.683,and 2.421;P<0.05).CONCLUSION The upregulated expression of MACC1 and V-ATPase in colon cancer patients appears to correlate with clinicopathological features and post-radical surgery recurrence.

AHA发布2024心脏病与脑卒中统计报告

近期,美国心脏协会(AHA)发布了美国和全球2024年心脏病和脑卒中统计报告。报告介绍,1924年AHA成立,1927年5月开始报告心脏病死亡率统计数据,自1921年以来,心脏病一直是美国的主要死因,1950年以来,心血管死亡率下降了60%,但近年来呈上升趋势,报告也在不断变化。

杂草对AHAS抑制剂的抗药性分子机理研究进展

除草剂在田间的重复及不合理使用,导致了杂草抗药性的发生和发展。其中AHAS抑制剂由于靶标单一,抗性发展十分迅速。截至2009年,已有103种杂草对AHAS抑制剂产生了抗药性,占19类化学除草剂总抗药性杂草生物型的近1/3。从AHAS基因突变位点及种类与杂草抗药性水平的关系、AHAS基因突变与AHAS酶活性的关系、AHAS基因拷贝数与杂草抗药性的关系以及AHAS酶与除草剂结合前后的三维结构等方面,综述了杂草对AHAS抑制剂产生抗药性的机理,旨在为AHAS抑制剂抗性研究提供参考。并对自然种群目标基因的等位基因检测技术(ECOTILLING)和衍生型酶切扩增多态性序列(dCAPS)两种通过检测等位基因多态性的手段快速诊断抗药性杂草的新技术进行了介绍,讨论了延缓杂草抗药性发生和发展的策略。

新型取代苯甲酰胺类化合物的合成及对AHAS酶的抑制和除草活性

在对乙酰乳酸合成酶(AHAS)抑制剂进行生物合理设计的基础上,分别以4-氟-3硝基苯胺和2-胺基-5硝基苯腈为原料,合成了8个苯磺酰胺基苯甲酰胺类化合物和7个双苯磺酰胺基苯甲酰胺类化合物,其结构通过核磁共振谱、质谱、红外光谱及元素分析验证.初步的生物活性测定结果表明,部分化合物在体内和体外均具有一定的生物活性,其中化合物4c,4d和7c在100μg/mL浓度下对拟南芥AHAS的抑制率分别为66%,76%和68%,而化合物4a,4c,7a和7b在100μg/mL浓度下对油菜根长的抑制率分别为76%,70%,89%和82%.研究结果为进一步设计合成潜在的AHAS抑制剂提供了有益参考.

一些吲哚二酮类衍生物的合成及对AHAS的抑制活性

基于一些新结构特征的AHAS抑制剂,设计并合成了一系列吲哚二酮类化合物.初步的生物活性测试结果表明,所合成的化合物在体内和体外均具有一定的生物活性,其中,化合物13在100μg/mL浓度下对AHAS的抑制达到85%,化合物7(平皿法)在100μg/mL浓度条件下对油菜胚根生长抑制率可达84.7%,是一类未见文献报道的结构新型的AHAS抑制剂,有望为进一步设计合成更高活性的化合物提供参考.