木薯SDH蛋白的序列分析及其与MeH1.2关系的研究

【目的】山梨糖醇脱氢酶(SDH)在调控蔷薇科植物果糖和山梨醇转化中起重要作用,也参与植物对逆境的应答过程,木薯SDH功能的研究可以为培育优质木薯种质提供理论基础。【方法】以‘SC124’的cDNA为模板克隆木薯SDH基因,并利用实时荧光定量PCR分析木薯SDH基因的组织特异性及其对干旱、低温、PEG和ABA的响应模式。通过筛选木薯干旱和低温混合的酵母cDNA文库,并利用Y2H点对点及其双分子荧光互补(BiFC)实验确认与目标蛋白的关系。【结果】木薯SDH基因CDS全长1092 bp,编码364个氨基酸,与数据库中的序列无差异。MeSDH蛋白含有催化锌结合位点,NADP结合位点,结构锌结合位点,属于MDR超家族。烟草叶片表皮细胞瞬时表达显示MeSDH蛋白定位于细胞核。MeSDH基因的表达量在功能叶、幼嫩叶、须根和茎中依次降低。MeSDH基因受干旱、低温和PEG胁迫诱导在木薯叶片上调表达,在ABA处理后的木薯叶片和根系中都显著上调表达。文库筛选、Y2H点对点和BiFC实验证实MeH1.2与MeSDH互作。【结论】MeSDH基因可以响应多种胁迫上调表达,并可能在蛋白水平和MeH1.2共同作用。

Selenium Differentially Regulates Flavonoid Accumulation and Antioxidant Capacities in Sprouts of Twenty Diverse Mungbean(Vigna radiata(L.)Wilczek)Genotypes

Seed germination with selenium(Se)is promising for producing Se-biofortified foods.Mungbean(Vigna radiata(L.)Wilczek)sprout is freshly eaten as a salad dressed with sauce,making it superior for Se biofortification.Since the Se safety range for the human body is extremely narrow,it is imperative to evaluate the genotypic responses of mungbean sprouts to Se.This study evaluated the Se enrichment capacity and interaction withflavonoids and antioxidant systems in sprouts of 20 mungbean germplasms.Selenium treatment was done by immersing mung-bean seeds in 20μM sodium selenite solution for 8 h.Afterward,the biomass,Se amounts,flavonoid(particularly vitexin and isovitexin)contents,antioxidant capacity,and key biosynthetic gene expressions were measured.Sprout Se content was 2.0-7.0μg g^(-1) DW among the 20 mungbean germplasms.Selenium treatment differentially affected the biomass,totalflavonoid,vitexin,isovitexin,antioxidant enzyme activities,and antioxidant capacities of the mungbean germplasms.Eight germplasms showed increased biomass(p<0.05),the highest increasing by 127%,but 13 did not phenotypically respond to Se treatment.Seven and six germplasms showed varied levels of vitexin and isovitexin increment after Se treatment,the highest measuring 2.67-and 2.87-folds for vitexin and isovitexin,respectively.Two mungbeanflavonoid biosynthesis genes,chalcone synthase(VrCHS)and chalcone isomerase(VrCHI)were significantly up-regulated in the germplasms with increased vitexin and isovitexin levels(p<0.05).Moreover,Se enrichment capacity was significantly correlated with the vitexin,isovitexin,and antiox-idant capacities.In conclusion,mungbean sprouts could be a useful Se-biofortified food,but the Se enrichment capacity and nutritional response must be determined for each germplasm before commercialization.

Repressing iron overload ameliorates central poststroke pain via the Hdac2-Kv1.2 axis in a rat model of hemorrhagic stroke

Thalamic hemorrhage can lead to the development of central post-stroke pain.Changes in histone acetylation levels,which are regulated by histone deacetylases,affect the excitability of neurons surrounding the hemorrhagic area.However,the regulato ry mechanism of histone deacetylases in central post-stroke pain remains unclea r.Here,we show that iron overload leads to an increase in histone deacetylase 2expression in damaged ventral posterolateral nucleus neurons.Inhibiting this increase restored histone H3 acetylation in the Kcna2 promoter region of the voltage-dependent potassium(Kv)channel subunit gene in a rat model of central post-stroke pain,thereby increasing Kcna2expression and relieving central pain.However,in the absence of nerve injury,increasing histone deacetylase 2 expression decreased Kcna2expression,decreased Kv current,increased the excitability of neurons in the ventral posterolateral nucleus area,and led to neuropathic pain symptoms.Moreover,treatment with the iron chelator deferiprone effectively reduced iron overload in the ventral posterolateral nucleus after intracerebral hemorrhage,reversed histone deacetylase 2 upregulation and Kv1.2 downregulation,and alleviated mechanical hypersensitivity in central post-stroke pain rats.These results suggest that histone deacetylase 2 upregulation and Kv1.2 downregulation,mediated by iron overload,are important factors in central post-stroke pain pathogenesis and co uld se rve as new to rgets for central poststroke pain treatment.

SlSnRK1.2调控番茄抗灰霉病功能分析

【背景】由灰葡萄孢(Botrytis cinerea)侵染番茄(Solanum lycopersicum)引起的灰霉病严重威胁番茄生产。植物蔗糖非发酵-1-相关蛋白激酶-1(sucrose non-fermenting-1-related protein kinase 1,SnRK1)参与多种植物对生物胁迫和非生物胁迫响应的调控,然而,番茄SnRK1是否参与对灰霉病抗性未见报道。【目的】以灰葡萄孢侵染番茄过程中上调表达的SlSnRK1.2为研究对象,克隆并分析其调控灰霉病抗性功能,为番茄灰霉病防治提供理论依据和基因资源。【方法】采用实时荧光定量PCR(real-time fluorescence quantitative PCR,qRT-PCR)技术,分析SlSnRK1.2在灰葡萄孢侵染番茄过程中以及在番茄不同组织中的表达模式;利用农杆菌介导的瞬时表达技术分析SlSnRK1.2的亚细胞定位情况;借助烟草脆裂病毒(tobacco rattle virus,TRV)介导的基因沉默技术(virus induced gene silencing,VIGS)构建SlSnRK1.2沉默植株,初步分析SlSnRK1.2在番茄与灰葡萄孢互作过程中的作用;利用农杆菌介导的番茄遗传转化体系创制SlSnRK1.2过表达植株,进一步明确SlSnRK1.2在调控番茄对灰霉病抗性中的作用;利用TRV-VIGS技术构建SlSnRK1.2同源基因NbSnRK1.2的沉默植株,分析NbSnRK1.2在烟草与灰葡萄孢互作中的作用。【结果】以Micro-Tom为材料,利用qRT-PCR技术明确SlSnRK1.2的转录表达显著受到灰葡萄孢侵染诱导;亚细胞定位结果显示SlSnRK1.2定位于细胞质和细胞核;qRT-PCR分析表明,SlSnRK1.2在番茄的根、茎、幼嫩叶片、成熟叶片、花蕾和花中均有表达,在茎部的表达量最高;瞬时沉默SlSnRK1.2减弱番茄对灰霉病的抗性,过表达SlSnRK1.2增强番茄对灰霉病的抗性;在此基础上,瞬时沉默SlSnRK1.2的同源基因NbSnRK1.2减弱烟草对灰霉病的抗性。【结论】SlSnRK1.2正调控番茄对灰霉病的抗性,可作为番茄抗灰霉病分子育种的基因资源。

晶化制度对Mg_(0.6)Al_(1.2)Si_(1.8)O_(6)透明微晶玻璃结构与性能的影响

MgO-Al_(2)O_(3)-SiO_(2)(MAS)系统微晶玻璃具有较高的机械强度、较低的介电损耗以及良好的化学稳定性和热稳定性等优点,在电子、军事、建筑等领域表现出极大的应用价值。采用熔融法,通过控制Mg_(0.6)Al_(1.2)Si_(1.8)O_(6)固溶体晶相的析出以制备MAS透明微晶玻璃。采用XRD、SEM和UV-Vis-NIR等测试手段研究了晶化制度对微晶玻璃结构和性能的影响。结果表明:晶化温度从950℃升高到1020℃,试样中析出Mg_(0.6)Al_(1.2)Si_(1.8)O_(6),微晶玻璃透明;当晶化温度为1050℃及更高温度时,试样中析出堇青石,微晶玻璃失透。随晶化温度的升高,玻璃发生Mg_(0.6)Al_(1.2)Si_(1.8)O_(6)向堇青石的晶相转变。与堇青石相比,Mg_(0.6)Al_(1.2)Si_(1.8)O_(6)晶相折射率更接近玻璃相折射率。晶化时间由2 h延长至10 h,微晶玻璃的晶相含量由42.9%(质量分数)提高至97.5%;晶化4~10 h的微晶玻璃中晶粒平均尺寸由17.50μm增大至30.58μm。随着晶化时间的延长,微晶玻璃透光率呈现缓慢下降的趋势,热膨胀系数缓慢增加,维氏硬度呈现先增大后平缓的趋势,抗折强度先增加后减小。微晶玻璃最佳晶化制度为晶化温度1020℃,晶化时间8 h。最佳晶化制度下的微晶玻璃具有较好的综合性能,其可见光区的透光率为83%,热膨胀系数为3.857×10^(-6)/℃(600℃),维氏硬度为10.2 GPa,抗折强度为200 MPa。

Development and application of a SYBR Green I fuorescent PCR assay for the diferentiation of genotypes I and II African swine fever viruses

African swine fever(ASF)is a highly fatal hemorrhagic disease afecting domestic pigs caused by African swine fever virus(ASFV).Genetic analysis of ASFV isolates to date has identifed 24 geographically related genotypes with various subgroups,but only genotype I and II ASFVs have been reported outside Africa.ASFV genotype II and genotype I viruses were reported in China in 2018 and 2021,respectively.In this study,unique and highly conserved noncoding regions were found between MGF_505-9R and MGF_505-10R in the 188 genomes of ASFV genotypes I and II.A pair of primers was designed on the basis of this region.By optimizing the reaction system and conditions,a SYBR Green I fuorescence PCR assay that can distinguish between ASFV genotypes I and II was established,and the sensitivity,reproducibility and specifcity were evaluated.The detection limit was 1 TCID_(50)/0.1 mL for both genotypes,with no cross-reactivity observed with other common pig pathogens.The intra-and interbatch variation coefcients were both less than 1.2%.Clinical sample detection analysis revealed 47 positive cases out of 100,including 3 for genotype I and 44 for genotype II,aligning with results from the WOAH-recommended and national standard methods.The method developed in this study allows for the diferentiation of ASFV genotypes I and II without the need for genome sequencing,ofering a convenient and rapid approach for ASFV detection and genotype identifcation.

Identification of S-RNase genotype and analysis of its origin and evolutionary patterns in Malus plants

Identification of the S genotype of Malus plants will greatly promote the discovery of new genes,the cultivation and production of apple,the breeding of new varieties,and the origin and evolution of self-incompatibility in Malus plants.In this experiment,88 Malus germplasm resources,such as Aihuahong,Xishuhaitang,and Reguanzi,were used as materials.Seven gene-specific primer combinations were used in the genotype identification.PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials.The results revealed that 70 of the identified materials obtained a complete S-RNase genotype,while only one S-RNase gene was found in 18 of them.Through homology comparison and analysis,13 S-RNase genotypes were obtained:S_(1)S_(2)(Aihuahong,etc.),S_(1)S_(28)(Xixian Haitang,etc.),S_(1)S_(51)(Hebei Pingdinghaitang),S_(1)S_(3)(Xiangyangcun Daguo,etc.),S_(2)S_(3)(Zhaiyehaitang,etc.),S_(3)S_(51)(Xishan 1),S_(3)S_(28)(Huangselihaerde,etc.),S_(2)S_(28)(Honghaitang,etc.),S_(4)S_(28)(Bo 11),S_(7)S_(28)(Jiuquan Shaguo),S_(10)S_e(Dongchengguan 13),S_(10)S_(21)(Dongxiangjiao)and S_(3)S_(51)(Xiongyue Haitang).Simultaneously,the frequency of the S gene in the tested materials was analyzed.The findings revealed that different S genes had varying frequencies in Malus resources,as well as varying frequencies between intraspecific and interspecific.S_(3) had the highest frequency of 68.18%,followed by S_(1)(42.04%).In addition,the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species,that cultivated species also evolved new S genes,and that the S_(50) gene is the oldest S allele in Malus plants.The S_(1),S_(29),and S_(33) genes in apple-cultivated species,on the other hand,may have originated in M.sieversii,M.hupehensis,and M.kansuensis,respectively.In addition to M.sieversii,M.kansuensis and M.sikkimensis may have also played a role in the origin and evolution of some Chinese apples.

Correlation between genotypes of Orientia tsutsugamushi and clinical characteristics of patients with scrub typhus in Guangzhou,China

Objective:To explore the correlation between genotypes of Orientia(O.)tsutsugamushi and clinical characteristics of scrub typhus patients.Methods:Clinical data of patients with scrub typhus admitted to different types of medical institutions in Guangzhou from September 2012 to December 2016 were collected using medical records.Demographic data,clinical manifestations,as well as hematological and biochemical indicators of patients infected with different genotypes were analyzed and compared.Results:A total of 192 patients were included in this study,including 121 patients with Karp genotype of O.tsutsugamushi infection(63.0%),36 patients with Gilliam genotype(19.0%),23 patients with Kato genotype(12.0%),and 12 patients with TA763 genotype(6.0%)infection.The median value of albumin in patients with Karp genotype infection was significantly lower than that of Gilliam-infected patients(P=0.032).Patients with Karp genotype infection had a significantly longer hospital stay(9 days)than those with Gilliam genotype(7 days)(P=0.009)and Kato genotype infection(6 days)(P=0.005).Karp-infected patients also represented for the largest number of patients with complicated organ involvement(88/133,66.2%).Furthermore,Karp-infected patients had higher risk of developing multiple organ dysfunction syndrome(18.2%)and requiring intensive care unit treatment(15.9%).Besides,patients with Gilliam genotype(8 days)and TA763 genotype infection(7.5 days)had shorter fever duration than those with Karp genotype(9 days)and Kato genotype(9 days)infection,respectively.Conclusions:Genotypes of Orientia tsutsugamushi were associated with varying clinical manifestations,organ involvement,and treatment outcomes,suggesting that genotypes ranged in virulence.

High Diversity in Genotypes of Human Rhinovirus Contributes to High Prevalence in Beijing,2018-2022:A Retrospective Multiple-Center Epidemiological Study

Objective To comprehensively examine the molecular epidemiological characteristics of human rhinovirus(HRV)in Beijing.Methods A total of 7,151 children and adults with acute respiratory tract infections(ARTIs)were recruited from 35 sentinel hospitals in Beijing between 2018 and 2022.Their respiratory samples were obtained,and epidemiological and clinical data were collected.Nucleic acid testing for 11 respiratory pathogens,including HRV,was performed on the specimens.We sequenced VP4/VP2 or 5’UTR of HRV isolates to identify their genotypes using phylogenetic analyses.Results HRV was detected in 462(6.5%)cases.A total of 105 HRV genotypes were successfully identified in 359(77.7%)specimens,comprising 247(68.8%)with HRV-A,42(11.7%)with HRV-B,and 70(19.5%)with HRV-C.No predominant genotype was observed.HRV was prevalent year-round with two weak peaks in spring and autumn.HRV detection declined gradually between 2018 and 2022,with seven genotypes disappearing and five genotypes emerging.HRV detection rate decreased by age without resurge among old people.HRV-C was more common among children aged less than 5 years with severe community-acquired pneumonia compared to HRV-A and HRV-B.Adults infected with HRV-B had higher rates of hospitalization,intensive care unit admission,and complications than those infected with HRV-A and HRV-C.Conclusion HRV epidemics in Beijing were highly dispersed in genotypes,which probably resulted in a high prevalence of HRV infection,attenuated its seasonality,and made it more difficult to establish effective population immunity.

Presence of a long nuclear-localization signal sequence in homeodomain transcription factor Nkx 1.2

Homeodomains,a 60-amino acid sequence encoded by 180 nucleotides,are highly conserved DNA-binding motifs that are present in a variety of transcription factors in species ranging from yeast to humans.The NKX proteins belong to the homeodomain(HD)-containing transcription factor family.They play vital roles in the regulation of morphogenesis.NKX1-2 is one member of the NKX subfamily.At present,information about its nuclear localization signal(NLS)sequence is limited.We studied the NLS sequence of zebrafish Nkx1.2 by introducing sequence changes such as deletion,mutation,and truncation,and identified an NLS motif(QNRRTKWKKQ)that is localized at the C-terminus of the homeodomain.Moreover,the deletion of two amino acid residues(RR)in this NLS motif prevents Nkx1.2 from entering the nucleus,indicating that the two amino acids are essential for Nkx1.2 nuclear localization.However,the NLS motif alone is unable to target cytoplasmic protein glutathione S-transferase(GST)to the nucleus.An intact homeodomain is necessary for mediating the complete nuclear transport of cytoplasmic protein.Unlike most nuclear import proteins with short NLS sequences,a long NLS is present in zebrafish Nkx1.2.We also demonstrated that the sequences of homeodomain of NKX1.2 are well conserved among different species.This study is informative to verify the function of the NKX1.2 protein.

Characterization of early maturing elite genotypes based on MTSI and MGIDI indexes:an illustration in upland cotton(Gossypium hirsutum L.)

Background Globally,the cultivation of cotton is constrained by its tendency for extended periods of growth.Early maturity plays a potential role in rainfed-based multiple cropping system especially in the current era of climate change.In the current study,a set of 20 diverse Gossypium hirsutum genotypes were evaluated in two crop seasons with three planting densities and assessed for 11 morphological traits related to early maturity.The study aimed to identify genotype(s)that mature rapidly and accomplish well under diverse environmental conditions based on the two robust multivariate techniques called multi-trait stability index(MTSI)and multi-trait genotype-ideotype distance index(MGIDI).Results MTSI analysis revealed that out of the 20 genotypes,three genotypes,viz.,NNDC-30,A-2,and S-32 accomplished well in terms of early maturity traits in two seasons.Furthermore,three genotypes were selected using MGIDI method for each planting densities with a selection intensity of 15%.The strengths and weaknesses of the genotypes selected based on MGIDI method highlighted that the breeders could focus on developing early-maturing genotypes with specific traits such as days to first flower and boll opening.The selected genotypes exhibited positive genetic gains for traits related to earliness and a successful harvest during the first and second pickings.However,there were negative gains for traits related to flowering and boll opening.Conclusion The study identified three genotypes exhibiting early maturity and accomplished well under different planting densities.The multivariate methods(MTSI and MGIDI)serve as novel approaches for selecting desired genotypes in plant breeding programs,especially across various growing environments.These methods offer exclusive benefits and can easily construe and minimize multicollinearity issues.

Hepatitis B virus genotypes in precision medicine of hepatitis Brelated hepatocellular carcinoma:Where we are now

Hepatitis B virus(HBV)infection is a major player in chronic hepatitis B that may lead to the development of hepatocellular carcinoma(HCC).HBV genetics are diverse where it is classified into at least 9 genotypes(A to I)and 1 putative genotype(J),each with specific geographical distribution and possible different clinical outcomes in the patient.This diversity may be associated with the precision medicine for HBV-related HCC and the success of therapeutical approaches against HCC,related to different pathogenicity of the virus and host response.This Editorial discusses recent updates on whether the classification of HBV genetic diversity is still valid in terms of viral oncogenicity to the HCC and its precision medicine,in addition to the recent advances in cellular and molecular biology technologies.

Serological Investigation into the Infected Genotypes of Patients with Japanese Encephalitis in the Coastal Provinces of China

Objective Genotypes(G)1,3,and 5 of the Japanese encephalitis virus(JEV)have been isolated in China,but the dominant genotype circulating in Chinese coastal areas remains unknown.We searched for G5 JEV-infected cases and attempted to elucidate which JEV genotype was most closely related to human Japanese encephalitis(JE)in the coastal provinces of China.Methods In this study,we collected serum specimens from patients with JE in three coastal provinces of China(Guangdong,Zhejiang,and Shandong)from 2018 to 2020 and conducted JEV cross-neutralization tests against G1,G3,and G5.Results Acute serum specimens from clinically reported JE cases were obtained for laboratory confirmation from hospitals in Shandong(92 patients),Zhejiang(192 patients),and Guangdong(77 patients),China,from 2018 to 2020.Seventy of the 361 serum specimens were laboratory-confirmed to be infected with JEV.Two cases were confirmed to be infected with G1 JEV,32 with G3 JEV,and two with G5 JEV.Conclusion G3 was the primary infection genotype among JE cases with a definite infection genotype,and the infection caused by G5 JEV was confirmed serologically in China.

Multidimensional evaluation of salt tolerance in groundnut genotypes through biochemical responses

The manuscript explores the complex interplay between groundnut genotypes,salt tolerance and hormonal influence,shedding light on the dynamic responses of three specific groundnut genotypes,KDG-128,TG-37 A and GG-20,to salt treatments and gibberellic acid(GA3).The study encompasses germination,plant growth,total protein content and oil content as key parameters.Through comprehensive analysis,it identifies TG-37 A and KDG-128 as salt-tolerant genotypes,and GG-20 as salt-susceptible genotypes,which highlighting the potential for targeted breeding efforts to develop more resilient groundnut varieties.Moreover,the quantification of protein and oil content under different treatments provides vital data for optimizing nutritional profiles in groundnut cultivars.Principal Component Analysis(PCA) underscores the significance of the first principal component(PC1)in explaining the majority of variance,capturing primary trends and differences in plant length.Analysis of Variance(ANOVA) and hierarchical analysis confirm the presence of statistically significant differences in protein and oil content among the genotypes.Pearson's correlation coefficient matrix analysis reveals strong positive correlations between plant length and protein content,plant length and oil content,and a moderately positive correlation between protein content and oil content.These findings provide valuable insights into groundnut physiology,salt tolerance,and nutritional composition,with implications for future research in sustainable agriculture and crop improvement.

Genotype-based precision nutrition strategies for the prediction and clinical management of type 2 diabetes mellitus

Globally,type 2 diabetes mellitus(T2DM)is one of the most common metabolic disorders.T2DM physiopathology is influenced by complex interrelationships between genetic,metabolic and lifestyle factors(including diet),which differ between populations and geographic regions.In fact,excessive consumptions of high fat/high sugar foods generally increase the risk of developing T2DM,whereas habitual intakes of plant-based healthy diets usually exert a protective effect.Moreover,genomic studies have allowed the characterization of sequence DNA variants across the human genome,some of which may affect gene expression and protein functions relevant for glucose homeostasis.This comprehensive literature review covers the impact of gene-diet interactions on T2DM susceptibility and disease progression,some of which have demonstrated a value as biomarkers of personal responses to certain nutritional interventions.Also,novel genotype-based dietary strategies have been developed for improving T2DM control in comparison to general lifestyle recommendations.Furthermore,progresses in other omics areas(epigenomics,metagenomics,proteomics,and metabolomics)are improving current understanding of genetic insights in T2DM clinical outcomes.Although more investigation is still needed,the analysis of the genetic make-up may help to decipher new paradigms in the pathophysiology of T2DM as well as offer further opportunities to personalize the screening,prevention,diagnosis,management,and prognosis of T2DM through precision nutrition.

Risk factors for hepatocellular carcinoma associated with hepatitis C genotype 3 infection:A systematic review

BACKGROUND Hepatitis C virus(HCV)is a blood-borne virus which globally affects around 79 million people and is associated with high morbidity and mortality.Chronic infection leads to cirrhosis in a large proportion of patients and often causes hepatocellular carcinoma(HCC)in people with cirrhosis.Of the 6 HCV genotypes(G1-G6),genotype-3 accounts for 17.9%of infections.HCV genotype-3 responds least well to directly-acting antivirals and patients with genotype-3 infection are at increased risk of HCC even if they do not have cirrhosis.AIM To systematically review and critically appraise all risk factors for HCC secondary to HCV-G3 in all settings.Consequently,we studied possible risk factors for HCC due to HCV-G3 in the literature from 1946 to 2023.METHODS This systematic review aimed to synthesise existing and published studies of risk factors for HCC secondary to HCV genotype-3 and evaluate their strengths and limitations.We searched Web of Science,Medline,EMBASE,and CENTRAL for publications reporting risk factors for HCC due to HCV genotype-3 in all settings,1946-2023.RESULTS Four thousand one hundred and forty-four records were identified from the four databases with 260 records removed as duplicates.Three thousand eight hundred and eighty-four records were screened with 3514 excluded.Three hundred and seventy-one full-texts were assessed for eligibility with seven studies included for analysis.Of the seven studies,three studies were retrospective case-control trials,two retrospective cohort studies,one a prospective cohort study and one a cross-sectional study design.All were based in hospital settings with four in Pakistan,two in South Korea and one in the United States.The total number of participants were 9621 of which 167 developed HCC(1.7%).All seven studies found cirrhosis to be a risk factor for HCC secondary to HCV genotype-3 followed by higher age(five-studies),with two studies each showing male sex,high alpha feto-protein,directly-acting antivirals treatment and achievement of sustained virologic response as risk factors for developing HCC.CONCLUSION Although,studies have shown that HCV genotype-3 infection is an independent risk factor for end-stage liver disease,HCC,and liver-related death,there is a lack of evidence for specific risk factors for HCC secondary to HCV genotype-3.Only cirrhosis and age have demonstrated an association;however,the number of studies is very small,and more research is required to investigate risk factors for HCC secondary to HCV genotype-3.

丹参Remorin基因SmREM1.2的克隆及生物信息学和表达分析

Remorin蛋白是一类植物特异的寡聚丝状蛋白,定位于细胞膜,介导脂筏微区形成,在植物逆境胁迫应答及植物免疫调节等过程中发挥重要作用。丹参是我国大宗类中药材,广泛用于心脑血管疾病等的治疗。但目前丹参Remorin蛋白的相关研究报道还不多。本研究基于丹参转录组及基因组数据库,克隆得到丹参Remorin基因SmREM1.2,通过生物信息学方法对其氨基酸组成、保守序列、系统进化进行分析,并对其亚细胞定位及在盐胁迫下的表达情况进行分析。结果表明,该基因CDS全长585 bp,编码194个氨基酸残基。SmREM1.2蛋白为弱酸性不稳定的亲水性蛋白,无信号肽,无跨膜区,含有Remorin_N和Remorin_C保守结构域,二级结构以α螺旋和无规则卷曲为主;氨基酸序列分析结果显示其C端具有高度保守的coiled-coil模体,属于典型的REM蛋白;系统进化树分析结果表明SmREM1.2与芡欧鼠尾草(Salvia hispanica)的Remorin蛋白亲缘关系较近。构建pCAMBIA-SmREM1.2-GFP重组载体,利用烟草瞬时转化系统对SmREM1.2进行亚细胞定位分析,发现该蛋白定位于细胞膜上。通过实时荧光定量PCR分析发现SmREM1.2受盐胁迫诱导上调表达,推测其在盐胁迫下发挥重要作用。本研究结果可为后期深入探索SmREM1.2基因的功能及应用提供理论依据。

Subclinical hepatitis E virus genotype 1 infection:The concept of“dynamic human reservoir”

Hepatitis E virus(HEV)is hyperendemic in South Asia and Africa accounting for half of total Global HEV burden.There are eight genotypes of HEV.Among them,the four common ones known to infect humans,genotypes 1 and 2 are prevalent in the developing world and genotypes 3 and 4 are causing challenge in the industrialized world.Asymptomatic HEV viremia in the general population,especially among blood donors,has been reported in the literature worldwide.The clinical implications related to this asymptomatic viremia are unclear and need further exploration.Detection of viremia due to HEV genotype 1 infection,apparently among healthy blood donors is also reported without much knowledge about its infection rate.Similarly,while HEV genotype 3 is known to be transmitted via blood transfusion in humans and has been subjected to screening in many European nations,instances of transmission have also been documented albeit without significant clinical consequences.Epidemiology of HEV genotype 1 in endemic areas often show waxing and waning pattern.Occasional sporadic occurrence of HEV infection interrupted by outbreaks have been frequently seen.In absence of known animal reservoir,where HEV exists in between outbreak is a mystery that needs further exploration.However,occurrence of asymptomatic HEV viremia due to HEV genotype 1 during epidemiologically quiescent period may explain that this phenomenon may act as a dynamic reservoir.Since HEV genotype 1 infection cannot cause chronicity,subclinical transient infection and transmission of virus might be the reason it sustains in interepidemic period.This might be the similar phenomenon with SARS COVID-19 corona virus infection which is circulating worldwide in distinct phases with peaks and plateaus despite vaccination against it.In view of existing evidence,we propose the concept of“Dynamic Human Reservoir.”Quiescent subclinical infection of HEV without any clinical consequences and subsequent transmission may contribute to the existence of the virus in a community.The potential for transmitting HEV infection by asymptomatic HEV infected individuals by fecal shedding of virus has not been reported in literature.This missing link may be a key to Pandora's box in understanding epidemiology of HEV infection in genotype 1 predominant region.

SiC_(p)含量对SiC_(p)/Al-1.2Mg-0.6Si铝基复合材料组织和性能影响

采用粉末冶金法制备SiC_(p)/Al-1.2Mg-0.6Si铝基复合材料,分析了该复合材料的均匀性和界面结合情况,探讨了几种体积分数该复合材料的显微组织和性能变化。结果表明,SiC颗粒和基体之间的界面清晰平滑,界面结合良好,但随着热压温度的增加,SiC与基体间的微观缩孔和析出相逐渐增多。随着SiC颗粒含量的增加,材料的弹性模量、热导率显著提高,弯曲强度先升高后下降,而热膨胀系数逐渐降低。

均匀化退火工艺对中高强Al-1.1Mg-1.2Si-0.7Mn合金挤压棒材组织性能的影响

采用SEM、拉伸测试、硬度分析、电导率测量等仪器和方法研究了均匀化退火工艺对中高强Al-1.1Mg-1.2Si-0.7Mn合金挤压棒材组织性能的影响。结果表明:试验合金低熔点共晶开始熔化温度为587℃。单级均匀化退火条件下,随均匀化退火温度的升高,铸锭及挤压制品中Mg_(2)Si逐渐减少,挤压棒材表面粗糙度逐渐降低,但粗晶环厚度显著增加(超过525℃后显著增加)。此外,为研究低温均匀化退火对含Mn相析出程度的影响,还开展了低温(430℃3 h)+高温(550℃8 h)和高温(550℃8 h)+低温(430℃3 h)的双级均匀化退火试验,双级均匀化对控制含Mn相析出、抑制粗晶作用不明显。不同工艺均匀化退火的铸锭对挤压棒材T6态性能影响不大。