Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillanc...Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction(RT-PCR) for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever(〉38.0 °C) and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai'an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai'an.Interestingly,the common ancestors of the Huai'an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were(3.09-7.26)×10-3 substitutions/site per year(95% HPD:1.72×10-3 to 1.16×10-2).Conclusion Overall,the source of exposure of human H7N9 cases in Huai'an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.展开更多
The diversity of sulfate-reducing bacteria (SRB) from deep layers of deep-sea sediments [ more than 2 m bsf (below seafloor) ] of two sites (WO1 -3 and WPO1 -4) in a tropical West Pacific warm pool region was ch...The diversity of sulfate-reducing bacteria (SRB) from deep layers of deep-sea sediments [ more than 2 m bsf (below seafloor) ] of two sites (WO1 -3 and WPO1 -4) in a tropical West Pacific warm pool region was characterized by using molecular phylogenetic analysis. The results of culture-independent samples demonstrated that the dominant clones from both sites were related to Grampositive spore forming genus, Desulfotomaculum, which accounted for 36.8% of all the sequencing clones from Site WP01 - 3 and 62.8% from Site WP01 -4. However, the other SRB group which was generally reported to be predominant in the deep-sea sediments of other regions, δ- subclass of the proteobacteria was found to be in very low percentages. Therefore, it could be speculated that there existed a unique chemical environment in the deep-sea sediment of this warm pool region. When comparing the Desulfotomaculum sp. related sequences from both sites, it was revealed that though the Desulfotomaculum-like sequences from Site WP01 -3 were more diverse than those from Site WP01 -4, all these sequences from both sites showed high similarity and formed a new phylogenetically homogeneous cluster in the Desulfotomaculum genus which had never been reported before. Successful enrichment of SRB was only achieved from samples of Site WP01 -4 and the sequence analysis of culture-dependent samples further confirmed the dominance of Desulfotomaculum genus. But Desulfotomaculum-related sequences from culture-dependent and culture-independent samples belonged to two different clusters respectively. This difference showed the choice of cultivation to the microorganisms.展开更多
Chitin deacetylase (CDA;EC 3. 5. 1. 41) catalyzes the deacetylation of chitin. In this study, we successfully cloned and sequenced a chitin deacetylase gene from the red snow crab Chionoecetes japonicas. By using reve...Chitin deacetylase (CDA;EC 3. 5. 1. 41) catalyzes the deacetylation of chitin. In this study, we successfully cloned and sequenced a chitin deacetylase gene from the red snow crab Chionoecetes japonicas. By using reverse transcription-polymerase chain reaction (RT-PCR) and 5' and 3' rapid amplification of cDNA ends, we obtained a 2141-bp amplicon containing a chitin deacetylase gene (CjCDA) from the epidermis of C. japonicas. The amplicon contains a 1575-bp open reading frame that is predicted to encode a 525-amino acid protein. The structure predicted from the deduced amino acid sequence included an N-terminal signal peptide, chitin-binding domain (CBD), low-density lipoprotein receptor class A domain (LDL-A), and catalytic domain. Comparative analysis of the deduced amino acid sequence of CjCDA revealed the highest homology (74%) to gastrolith protein 59 of Cherax quadricarinatus. We used RT-PCR to evaluate the expression of CjCDA in various tissues of C. japonicas, and we observed that CjCDA was expressed only in the epidermis. A phylogenetic analysis, using the amino acid sequences of CjCDA and other known chitin deacetylases, showed that CjCDA belonged to a group of crustacean chitin deacetylases. To our knowledge, this is the first study reporting the cDNA cloning of a chitin deacetylase from a crab.展开更多
Encephalomyocarditis virus(EMCV)is a positive single-stranded small RNA virus without envelope,which can infect a variety of mammals.Swines are the most susceptible animals,which can cause acute myocarditis and respir...Encephalomyocarditis virus(EMCV)is a positive single-stranded small RNA virus without envelope,which can infect a variety of mammals.Swines are the most susceptible animals,which can cause acute myocarditis and respiratory failure in piglets and reproductive failure in pregnant sows.Diseases caused by EMCV have a wide range of effects on the global swine industry.In this study,a strain of EMCV was isolated from a swine aborted fetus in northeast China.It was identified by reverse transcriptase polymerase chain reaction(RT-PCR),electron microscopic observation and indirect immunofluorescence assay.The subsequent results showed that the virus titer of HLJ strain grew to 8.3 lgTCID50 on baby hamster kidney 21(BHK-21)cells.And HLJ strain caused the specific cytopathic effect(CPE)on BHK-21 cells and severe pathological changes in mice.Complete genome sequencing and multiple sequence alignment showed that the homology between HLJ strain and other isolates worldwide was 71.5%-99.7%.Phylogenetic analysis showed that EMCV isolates fell into five clusters:lineageⅠ,Ⅱ,Ⅲ,ⅣandⅤ,based on the nucleotide sequences of the entire open reading frame(ORF)and VP1 gene.HLJ isolate was grouped into lineage I.The analyses of amino acid mutation sites of VP1 protein showed that the amino acids at positions 20 and 54 in VP1 junction were unique to HLJ strain.The isolation of HLJ strain enriched the epidemiological database of EMCV.展开更多
Goal of this study was to analyse the clinical course of cystic fibrosis (CF) patients with nontuberculous mycobacteria (NTM) in their respiratory secretions and to investigate the molecular epidemiology of the most p...Goal of this study was to analyse the clinical course of cystic fibrosis (CF) patients with nontuberculous mycobacteria (NTM) in their respiratory secretions and to investigate the molecular epidemiology of the most prevalent NTM species by multilocus sequence analysis (MLSA). The respiratory specimen and the clinical parameters forced expiratory volume in one second (FEV1), body-mass-index (BMI), erythrocyte sedimentation rate (ESR) 1 h and immunoglobulin G (IgG) of 357 CF patients, 0 - 52.4 years, mean FEV1 2009 81.5% pred were analysed between 1998 and 2010. In 13 patients NTM were detected. 12 of 13 patients carried M. abscessus, for one patient the NTM species was not characterized. 4 patients carried a second NTM species (M. avium, M. chelonae (2x), M. intracellulare). 6 patients exhibited a significant decline in FEV1, however changes in BMI, IgG and ESR were discordant. Molecular genotyping of M. abscessus isolates revealed a unique MLSA pattern in 6 patients. 2 patients harboured identical strains, and one patient a closely related strain. Whether the presence of identical strains is attributed to the acquisition of NTM clones from common environmental sources or to patient-to-patient transmission cannot be definitely clarified. Although cross-in- fection of the three patients with identical/closely related strains in the present cohort is highly unlikely, we recommend strict hygiene measures for all CF patients harbouring NTM.展开更多
Nipah virus(Ni V) is a member of the genus Henipavirus of the family Paramyxoviridae,characterized by high pathogenicity and endemic in South Asia.It is classified as a Biosafety Level-4(BSL-4) agent.The case-fatality...Nipah virus(Ni V) is a member of the genus Henipavirus of the family Paramyxoviridae,characterized by high pathogenicity and endemic in South Asia.It is classified as a Biosafety Level-4(BSL-4) agent.The case-fatality varies from 40%-70% depending on the severity of the disease and on the availability of adequate healthcare facilities.At present no antiviral drugs are available for Ni V disease and the treatment is just supportive.Phylogenetic and evolutionary analyses can be used to help in understanding the epidemiology and the temporal origin of this virus.This review provides an overview of evolutionary studies performed on Nipah viruses circulating in different countries.Thirty phylogenetic studies have been published from 2000 to 2015 years,searching on pub-med using the key words ‘Nipah virus AND phylogeny' and twenty-eight molecular epidemiological studies from 2006 to 2015 have been performed,typing the key words ‘Nipah virus AND molecular epidemiology'.Overall data from the published study demonstrated as phylogenetic and evolutionary analysis represent promising tools to evidence NiV epidemics,to study their origin and evolution and finally to act with effective preventive measure.展开更多
Influenza viruses(FLUV)cause high morbidity and mortality annually in the world and pose a serious threat to the public health.Wuhan,as an important transportation hub in China,has a dense population and suitable clim...Influenza viruses(FLUV)cause high morbidity and mortality annually in the world and pose a serious threat to the public health.Wuhan,as an important transportation hub in China,has a dense population and suitable climate,which also lays a major hidden danger for the outbreak of influenza.To survey and characterize the seasonal FLUV in Wuhan during 2016–2019,we collected 44,738 throat swabs,among which 15.5%were influenza A(FLUAV)positive,6.1%influenza B(FLUBV)and 0.3%co-infection.By monitoring FLUV in each month from June 2016 to May 2019,different with the previously seasonality pattern,only a single influenza peak was appeared in winter of 2017–2018 and 2018–2019,respectively.These data indicated that the complex circulation pattern of seasonal influenza in Wuhan.In addition,we found the age group was skewed towards 5–14 years group whose activity were mostly school based,which suggested school may be an important place for influenza outbreaks.Meanwhile,phylogenic analysis revealed that two subtypes(subclade 3C.2 a2 and 3C.2 a1b)of A(H3N2)were circulating in Wuhan and there was an obvious transition in 2018 because the two subclades were detected simultaneously.Furthermore,by estimating the vaccine effectiveness,we found that the vaccine strain of FLUAV didn’t seem to match very well the current epidemic strain,especially A(H3N2).Hence,more accurate prediction of seasonal outbreak is essential for vaccine design.Taken together,our results provided the current information about seasonal FLUV in Wuhan which form the basis for vaccine updating.展开更多
Background Coxsackievirus A16(CVA16)is one of the major etiological agents of hand,foot and mouth discase(HFMD).This study aimed to investigate the molecular epidemiology and evolutionary characteristics of CVA16.Meth...Background Coxsackievirus A16(CVA16)is one of the major etiological agents of hand,foot and mouth discase(HFMD).This study aimed to investigate the molecular epidemiology and evolutionary characteristics of CVA16.Methods Throat swabs were collected from children with HFMD and suspected HFMD during 2010-2019.Enteroviruses(EVs)were detected and typed by real-ime reverse transcription-polymerase chain reaction(RT-PCR)and RT-PCR.The genotype,evolutionary rate,the most recent common ancestor,population dynamics and selection pressure of CVA16 were analyzed based on viral protein gene(VPI)by bioinformatics software.Results A total of 4709 throat swabs were screened.EVs were detected in 3180 samples and 814 were CVA16 positive.More than 81%of CVA 16-positive children were under 5 years old.The prevalence of CVA 16 showed obvious periodic fluctuations with a high level during 2010--2012 followed by an apparent decline during 2013--2017.However,the activities of CVA16 increased gradually during 2018-2019.All the Beijing CVA16 strains belonged to sub-genotype BI,and B Ib was the dominant strain.One B Ic strain was detected in Bejing for the first time in 2016.The estimated mean evolutionary rate of VPI gene was 4.49x 103 substitution/site/year.Methionine gradually fixed at site-23 of VP1 since 2012.Two sites were detected under episodic positive selection,one of which(site-223)located in neutralizing linear epitope PEP71.Conclusions The dominant strains of CVA 16 belonged to clade B lb and evolved in a fast evolutionary rate during 2010-2019 in Beiing.To provide more favorable data for HFMD prevention and control,it is necessary to keep attention on molecular epidemiological and evolutionary characteristics of CVA16.展开更多
Group A streptococcus (GAS) causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to inv...Group A streptococcus (GAS) causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae, such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1]. GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency. M protein, one of the major virulence factors, is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.展开更多
Canine parvovirus 2(CPV-2)is a highly contagious virus in dogs that typically causes hemorrhagic enteritis and a high mortality rate in unvaccinated puppies.The genetic variability and antigenic diversity of CPV-2 hin...Canine parvovirus 2(CPV-2)is a highly contagious virus in dogs that typically causes hemorrhagic enteritis and a high mortality rate in unvaccinated puppies.The genetic variability and antigenic diversity of CPV-2 hinder its efective prevention of infection by vaccination.To investigate the epidemiology and genetic characteristics of CPV-2 in China,rectal swabs from afected dogs were collected from diferent animal clinics in Kunshan from 2022 to 2023.Preliminary detection and capsid gene sequencing of CPV-2 were performed using previously described primers and protocols.The overall detection rate for CPV-2 was 16.5%(33/200).A signifcant association was found between the CPV-2-positivity and clinical signs,age,breed and vaccination status.Sequence analysis revealed the presence of CPV-2c genotypes in all positive samples,which were genetically similar to other Asian CPV-2c strains.Notably,four key mutations(A5G,F267Y,Y324I and Q370R)were detected in all isolates,and one novel mutation(I447M)was detected in three CPV-2 isolates.These mutations in the CPV-2 strains could impact vaccine efcacy and the efectiveness of the virus immune evasion.Surprisingly,no recombination events were observed between the identifed CPV-2c strains and reference strains from China.Our data revealed that amino acid residues 324,426 and 440 of VP2 may under strong selection pressure.This pattern of genetic variation in the CPV-2 lineage warrants continuous laboratory-based surveillance programs in other parts of China to better understand the pattern of seasonal distribution and association between emerging genotypes and the intensity of disease severity.展开更多
Objective:To assess the association between X-ray repair cross-complementating group 1 (XRCC1) polymorphisms and pancreatic cancer.Methods:We searched MEDLINE,Web of Science and HuGE Navigator at June 2010,and the...Objective:To assess the association between X-ray repair cross-complementating group 1 (XRCC1) polymorphisms and pancreatic cancer.Methods:We searched MEDLINE,Web of Science and HuGE Navigator at June 2010,and then quantitatively summarized associations of the XRCC1 polymorphisms with pancreatic cancer risk using meta-analysis.Results:Four studies with 1343 cases and 2302 controls were included.Our analysis found:at codon 194,the Trp allele did not decrease pancreatic cancer risk (Arg/Arg versus Trp/Trp:OR=0.97;95% CI:0.48-1.96;P=0.97;Arg/Arg versus Arg/Trp:OR=0.89;95% CI:0.70-1.13;P=0.55;Arg/Trp versus Trp/Trp:OR=1.06;95% CI:0.52-2.16;P=0.90);at codon 280,only a study showed a nonsignificant association between single nucleotide polymorphism with pancreatic cancer risk;at codon 399,the Gln allele also showed no signi?cant effect on pancreatic cancer compared to Arg allele (Arg/Arg versus Gln/Gln:OR=0.94;95% CI:0.74-1.18;Arg/Arg versus Arg/Gln:OR=0.97;95% CI:0.83-1.13;Arg/Gln versus Gln/Gln:OR=0.97;95% CI:0.77-1.22).The shape of the funnel plot and the Egger's test did not detect any publication bias.Conclusion:There is no evidence that XRCC1 polymorphisms (Arg194Trp,Arg280His,and Arg399Gln) are associated with pancreatic cancer risk.展开更多
The purpose of this work is to study the molecular epiderniological characteristics of norovirus gastroenteritis outbreaks in Guangdong. During October 2003 and December 2004, fecal and anal swabs specimens collected ...The purpose of this work is to study the molecular epiderniological characteristics of norovirus gastroenteritis outbreaks in Guangdong. During October 2003 and December 2004, fecal and anal swabs specimens collected from 13 outbreaks of non-bacterial gastroenteritis were tested for nomvirus. Specimens were detected by RT-PCR and sequenced. The descriptive data were also collected. Eight in 13 outbreaks of gastroenteritis were positive for nomvirus. All of 8 virus strains were identified as genogroup Ⅱ but belonged to 3 genotypes. Six strains were G Ⅱ -4 genotype. Nomvirus is a major cause of outbreaks of nonbacterial gastroenteritis in Guangdong province and has a wide distribution. The illness happended from late autumn to winter. The prevalent strains were genogroup Ⅱ virus.展开更多
Duck circovirus (DuCV), a potential immunosuppressive virus, was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method. In this study, a total of 1...Duck circovirus (DuCV), a potential immunosuppressive virus, was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method. In this study, a total of 138 sick or dead duck samples from 18 different farms were examined with an average DuCV infection rate of-35%. It was found that ducks between the ages of 40~60 days were more susceptible to DuCV. There was no evidence showing that the DuCV virus was capable of vertical transmission. Farms with positive PCR results exhibited no regularly apparent clinical abnormalities such as feathering disorders, growth retardation or lower-than-average weight. The complete genomes of 91 strains from Fujian Province and 1 from Zhejiang Province were sequenced and analyzed. The 10 DuCV genomes, comlbared with others genomes downloaded from GenBank, ranged in size from 1988 to 1996 base pairs, with sequence identities ranging from 83.2% to 99.8%. Phylogenetic analysis based on genome sequences demonstrated that DuCVs can be divided into two distinct genetic genotypes, Group I (the Euro-USA lineage) and Group II(the Taiwan lineage), with approximately 10.0% genetic difference between the two types. Molecular epidemiological data suggest there is no obvious difference among DuCV strains isolated from different geographic locations or different species, including Duck, Muscovy duck, Mule duck, Cheery duck, Mulard duck and Pekin duck.展开更多
The genus Sheathia consists of over 20 species primarily distributed in Asia,Europe,Oceania,North America,and Africa.However,the origin and evolution of this genus remain unclear.Two gametophyte stage specimens(SAS180...The genus Sheathia consists of over 20 species primarily distributed in Asia,Europe,Oceania,North America,and Africa.However,the origin and evolution of this genus remain unclear.Two gametophyte stage specimens(SAS18052 and SAS18523)and two“Chantransia”stage specimens(YTS19161 and YTS19017)were collected from Shanxi and Henan Provinces in China,respectively.Based on morphological data,isolates YTS19161 and YTS19017 were similar to Audouinella pygmaea,whereas the morphological characteristics of SAS18052 and SAS18523 were in good agreement with the circumscription description of S.longipedicellata.Molecular sequences of rbc L,COI-5P,and psb A were used to investigate the phylogenetic,evolutionary,and biogeographic origin of the genus Sheathia.The three molecular markers supported that the two gametophyte stage specimens belong to S.longipedicellata,while the isolates YTS19161 and YTS19017 were the“Chantransia”of S.longipedicellata.Ancestral area reconstruction and divergence time estimation speculated that Sheathia originated in North America,a portion of the Pangaea at approximately 328.07-184.73 million years ago(Ma).Our relaxed molecular clock analysis suggests that the Florideophyceae diverged approximately 741.04(894.36-631.70)Ma.The major divergences in this class involved the emergence of Nemaliophycidae[ca.662.01(779.83-580.51)Ma],and the split of orders Batrachospermales and Thoreales[ca.456.10(552.80-367.88)Ma].展开更多
Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of...Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of R.palmatum and other Caryophyllales species for inferring phylogenetic relationships and species identification.Methods:Both Illumina short reads and PacBio HiFi reads were utilized to obtain a complete mitogenome of R.palmatum.A variety of bioinformatics tools were employed to characterize the R.palmatum mitogenome,compare the reported mitogenomes in Caryophyllales and conduct phylogenetic analysis.Results:The mitogenome of R.palmatum was assembled into a single master circle of 302,993 bp,encoding 35 known protein-coding genes,18 transfer RNA genes,and three ribosome RNA genes.A total of 249 long repeats and 49 simple sequence repeats were identified in this mitogenome.The sizes of mitogenomes in Caryophyllales varied from 253 kb to 11.3 Mb.Among them,23 mitogenomes were circular molecules,one was linear,and one consisted of relaxed circles,linear molecules,and supercoiled DNA.Out of the total mitogenomes,11 were single-chromosome structure,whereas the remaining 14 were multi-chromosomal organizations.The phylogenetic analysis is consistent with both the Engler system(1964)and the Angiosperm Phylogeny Group III system.Conclusions:We obtained the first mitogenome of R.palmatum,which consists of a master circle.Mitogenomes in Caryophyllales have variable genome sizes and structures even within the same species.Circular molecules are still the dominant pattern in Caryophyllales.Single-chromosome mitogenomes account for nearly a half of all the mitogenomes in Caryophyllales,in contrast to previous studies.It is feasible to utilize mitochondrial genomes for inferring phylogenetic relationships and conducting species identification.展开更多
In this study, we report that we successfully cloned and sequenced a chitinase gene from the ovotestis of Kuroda’s sea hare Aplysia kurodai. By using reverse transcription-polymerase chain reaction (RT-PCR) and a sys...In this study, we report that we successfully cloned and sequenced a chitinase gene from the ovotestis of Kuroda’s sea hare Aplysia kurodai. By using reverse transcription-polymerase chain reaction (RT-PCR) and a system for the 5’ and 3’ rapid amplification of cDNA ends, we obtained a 1352 bp chitinase gene (AkChi) from the ovotestis of A. kurodai. AkChi contains a 1263 bp open reading frame that encodes 421 amino acids. The domain structure predicted from the deduced amino acid sequence was an N-terminal signal peptide and a catalytic domain of glycoside hydrolase (GH) family 18 chitinase. A comparative analysis of the deduced amino acid sequences of AkChi with those of the acidic mammalian chitinase of the California sea hare Aplysia californica revealed the highest homology at 83%. The purified chitinase from the ovotestis was digested by trypsin, and 119 residues of digested peptides were consistent with the deduced amino acid sequence of AkChi. We used RT-PCR to evaluate the expression of AkChi in various tissues of A. kurodai, and we observed that AkChi was expressed only in the ovotestis. A phylogenetic tree analysis, performed using the amino acid sequences of AkChi and known GH family 18 chitinases, showed that AkChi was separated from the molluscan chitinases with a chitin binding domain. To our knowledge, this is the first study demonstrating the cDNA cloning of an ovotestis chitinase from a sea hare.展开更多
Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean...Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.展开更多
基金supported by grants HAYf201516 from Huai’an Preventive Medicine Associationgrant HAS2015019-3 from Huai’an Scientific Technological Special Project
文摘Objective To trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.Methods An enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an.Clinical specimens,cloacal swabs,and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction(RT-PCR) for H7N9 virus.The positive samples were subjected to further RT-PCR and genome sequencing.The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.Results Six patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever(〉38.0 °C) and headaches.Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure.Phylogenetic analysis revealed that all novel H7N9 viruses,including Huai'an strains,could be classified into two distinct clades,A and B.Additionally,the diversified H7N9 virus circulated in live poultry markets in Huai'an.Interestingly,the common ancestors of the Huai'an H7N9 virus existed in January 2012.The mean nucleotide substitution rates for each gene segment of the H7N9 virus were(3.09-7.26)×10-3 substitutions/site per year(95% HPD:1.72×10-3 to 1.16×10-2).Conclusion Overall,the source of exposure of human H7N9 cases in Huai'an was live poultry market,and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.
文摘The diversity of sulfate-reducing bacteria (SRB) from deep layers of deep-sea sediments [ more than 2 m bsf (below seafloor) ] of two sites (WO1 -3 and WPO1 -4) in a tropical West Pacific warm pool region was characterized by using molecular phylogenetic analysis. The results of culture-independent samples demonstrated that the dominant clones from both sites were related to Grampositive spore forming genus, Desulfotomaculum, which accounted for 36.8% of all the sequencing clones from Site WP01 - 3 and 62.8% from Site WP01 -4. However, the other SRB group which was generally reported to be predominant in the deep-sea sediments of other regions, δ- subclass of the proteobacteria was found to be in very low percentages. Therefore, it could be speculated that there existed a unique chemical environment in the deep-sea sediment of this warm pool region. When comparing the Desulfotomaculum sp. related sequences from both sites, it was revealed that though the Desulfotomaculum-like sequences from Site WP01 -3 were more diverse than those from Site WP01 -4, all these sequences from both sites showed high similarity and formed a new phylogenetically homogeneous cluster in the Desulfotomaculum genus which had never been reported before. Successful enrichment of SRB was only achieved from samples of Site WP01 -4 and the sequence analysis of culture-dependent samples further confirmed the dominance of Desulfotomaculum genus. But Desulfotomaculum-related sequences from culture-dependent and culture-independent samples belonged to two different clusters respectively. This difference showed the choice of cultivation to the microorganisms.
文摘Chitin deacetylase (CDA;EC 3. 5. 1. 41) catalyzes the deacetylation of chitin. In this study, we successfully cloned and sequenced a chitin deacetylase gene from the red snow crab Chionoecetes japonicas. By using reverse transcription-polymerase chain reaction (RT-PCR) and 5' and 3' rapid amplification of cDNA ends, we obtained a 2141-bp amplicon containing a chitin deacetylase gene (CjCDA) from the epidermis of C. japonicas. The amplicon contains a 1575-bp open reading frame that is predicted to encode a 525-amino acid protein. The structure predicted from the deduced amino acid sequence included an N-terminal signal peptide, chitin-binding domain (CBD), low-density lipoprotein receptor class A domain (LDL-A), and catalytic domain. Comparative analysis of the deduced amino acid sequence of CjCDA revealed the highest homology (74%) to gastrolith protein 59 of Cherax quadricarinatus. We used RT-PCR to evaluate the expression of CjCDA in various tissues of C. japonicas, and we observed that CjCDA was expressed only in the epidermis. A phylogenetic analysis, using the amino acid sequences of CjCDA and other known chitin deacetylases, showed that CjCDA belonged to a group of crustacean chitin deacetylases. To our knowledge, this is the first study reporting the cDNA cloning of a chitin deacetylase from a crab.
基金Supported by the National Natural Science Foundation of China(31372438)。
文摘Encephalomyocarditis virus(EMCV)is a positive single-stranded small RNA virus without envelope,which can infect a variety of mammals.Swines are the most susceptible animals,which can cause acute myocarditis and respiratory failure in piglets and reproductive failure in pregnant sows.Diseases caused by EMCV have a wide range of effects on the global swine industry.In this study,a strain of EMCV was isolated from a swine aborted fetus in northeast China.It was identified by reverse transcriptase polymerase chain reaction(RT-PCR),electron microscopic observation and indirect immunofluorescence assay.The subsequent results showed that the virus titer of HLJ strain grew to 8.3 lgTCID50 on baby hamster kidney 21(BHK-21)cells.And HLJ strain caused the specific cytopathic effect(CPE)on BHK-21 cells and severe pathological changes in mice.Complete genome sequencing and multiple sequence alignment showed that the homology between HLJ strain and other isolates worldwide was 71.5%-99.7%.Phylogenetic analysis showed that EMCV isolates fell into five clusters:lineageⅠ,Ⅱ,Ⅲ,ⅣandⅤ,based on the nucleotide sequences of the entire open reading frame(ORF)and VP1 gene.HLJ isolate was grouped into lineage I.The analyses of amino acid mutation sites of VP1 protein showed that the amino acids at positions 20 and 54 in VP1 junction were unique to HLJ strain.The isolation of HLJ strain enriched the epidemiological database of EMCV.
文摘Goal of this study was to analyse the clinical course of cystic fibrosis (CF) patients with nontuberculous mycobacteria (NTM) in their respiratory secretions and to investigate the molecular epidemiology of the most prevalent NTM species by multilocus sequence analysis (MLSA). The respiratory specimen and the clinical parameters forced expiratory volume in one second (FEV1), body-mass-index (BMI), erythrocyte sedimentation rate (ESR) 1 h and immunoglobulin G (IgG) of 357 CF patients, 0 - 52.4 years, mean FEV1 2009 81.5% pred were analysed between 1998 and 2010. In 13 patients NTM were detected. 12 of 13 patients carried M. abscessus, for one patient the NTM species was not characterized. 4 patients carried a second NTM species (M. avium, M. chelonae (2x), M. intracellulare). 6 patients exhibited a significant decline in FEV1, however changes in BMI, IgG and ESR were discordant. Molecular genotyping of M. abscessus isolates revealed a unique MLSA pattern in 6 patients. 2 patients harboured identical strains, and one patient a closely related strain. Whether the presence of identical strains is attributed to the acquisition of NTM clones from common environmental sources or to patient-to-patient transmission cannot be definitely clarified. Although cross-in- fection of the three patients with identical/closely related strains in the present cohort is highly unlikely, we recommend strict hygiene measures for all CF patients harbouring NTM.
文摘Nipah virus(Ni V) is a member of the genus Henipavirus of the family Paramyxoviridae,characterized by high pathogenicity and endemic in South Asia.It is classified as a Biosafety Level-4(BSL-4) agent.The case-fatality varies from 40%-70% depending on the severity of the disease and on the availability of adequate healthcare facilities.At present no antiviral drugs are available for Ni V disease and the treatment is just supportive.Phylogenetic and evolutionary analyses can be used to help in understanding the epidemiology and the temporal origin of this virus.This review provides an overview of evolutionary studies performed on Nipah viruses circulating in different countries.Thirty phylogenetic studies have been published from 2000 to 2015 years,searching on pub-med using the key words ‘Nipah virus AND phylogeny' and twenty-eight molecular epidemiological studies from 2006 to 2015 have been performed,typing the key words ‘Nipah virus AND molecular epidemiology'.Overall data from the published study demonstrated as phylogenetic and evolutionary analysis represent promising tools to evidence NiV epidemics,to study their origin and evolution and finally to act with effective preventive measure.
基金supported by the Fundamental Research Funds for the Central Universities and the National key research and development program of China(2018TFE0204500)
文摘Influenza viruses(FLUV)cause high morbidity and mortality annually in the world and pose a serious threat to the public health.Wuhan,as an important transportation hub in China,has a dense population and suitable climate,which also lays a major hidden danger for the outbreak of influenza.To survey and characterize the seasonal FLUV in Wuhan during 2016–2019,we collected 44,738 throat swabs,among which 15.5%were influenza A(FLUAV)positive,6.1%influenza B(FLUBV)and 0.3%co-infection.By monitoring FLUV in each month from June 2016 to May 2019,different with the previously seasonality pattern,only a single influenza peak was appeared in winter of 2017–2018 and 2018–2019,respectively.These data indicated that the complex circulation pattern of seasonal influenza in Wuhan.In addition,we found the age group was skewed towards 5–14 years group whose activity were mostly school based,which suggested school may be an important place for influenza outbreaks.Meanwhile,phylogenic analysis revealed that two subtypes(subclade 3C.2 a2 and 3C.2 a1b)of A(H3N2)were circulating in Wuhan and there was an obvious transition in 2018 because the two subclades were detected simultaneously.Furthermore,by estimating the vaccine effectiveness,we found that the vaccine strain of FLUAV didn’t seem to match very well the current epidemic strain,especially A(H3N2).Hence,more accurate prediction of seasonal outbreak is essential for vaccine design.Taken together,our results provided the current information about seasonal FLUV in Wuhan which form the basis for vaccine updating.
基金supported by the Key Technologies R&D Program of the National Ministry of Science(2018ZX10713001-003)the Special Fund of the Pediatric Medical Coordinated Development Center of Beijing Hospitals Authority(XTCX201822)the National Natural Science Foundation of China(81350019).
文摘Background Coxsackievirus A16(CVA16)is one of the major etiological agents of hand,foot and mouth discase(HFMD).This study aimed to investigate the molecular epidemiology and evolutionary characteristics of CVA16.Methods Throat swabs were collected from children with HFMD and suspected HFMD during 2010-2019.Enteroviruses(EVs)were detected and typed by real-ime reverse transcription-polymerase chain reaction(RT-PCR)and RT-PCR.The genotype,evolutionary rate,the most recent common ancestor,population dynamics and selection pressure of CVA16 were analyzed based on viral protein gene(VPI)by bioinformatics software.Results A total of 4709 throat swabs were screened.EVs were detected in 3180 samples and 814 were CVA16 positive.More than 81%of CVA 16-positive children were under 5 years old.The prevalence of CVA 16 showed obvious periodic fluctuations with a high level during 2010--2012 followed by an apparent decline during 2013--2017.However,the activities of CVA16 increased gradually during 2018-2019.All the Beijing CVA16 strains belonged to sub-genotype BI,and B Ib was the dominant strain.One B Ic strain was detected in Bejing for the first time in 2016.The estimated mean evolutionary rate of VPI gene was 4.49x 103 substitution/site/year.Methionine gradually fixed at site-23 of VP1 since 2012.Two sites were detected under episodic positive selection,one of which(site-223)located in neutralizing linear epitope PEP71.Conclusions The dominant strains of CVA 16 belonged to clade B lb and evolved in a fast evolutionary rate during 2010-2019 in Beiing.To provide more favorable data for HFMD prevention and control,it is necessary to keep attention on molecular epidemiological and evolutionary characteristics of CVA16.
文摘Group A streptococcus (GAS) causes a wide range of diseases in the human population. GAS diseases are more common in children than in adults, with clinical manifestations ranging from pharyngitis and impetigo to invasive infections and post streptococcal sequelae, such as acute rheumatic fever and acute post-streptococcal glomerulonephritis[1]. GAS harbors a host of virulence factors that contribute to its complex pathogenicity and differences in the disease severity and frequency. M protein, one of the major virulence factors, is encoded by the emm gene induces a type of specific host immune response and confers antiphagocytic properties.
基金Kunshan Municipal Government research funding(Grant Number:22KKSGR075).
文摘Canine parvovirus 2(CPV-2)is a highly contagious virus in dogs that typically causes hemorrhagic enteritis and a high mortality rate in unvaccinated puppies.The genetic variability and antigenic diversity of CPV-2 hinder its efective prevention of infection by vaccination.To investigate the epidemiology and genetic characteristics of CPV-2 in China,rectal swabs from afected dogs were collected from diferent animal clinics in Kunshan from 2022 to 2023.Preliminary detection and capsid gene sequencing of CPV-2 were performed using previously described primers and protocols.The overall detection rate for CPV-2 was 16.5%(33/200).A signifcant association was found between the CPV-2-positivity and clinical signs,age,breed and vaccination status.Sequence analysis revealed the presence of CPV-2c genotypes in all positive samples,which were genetically similar to other Asian CPV-2c strains.Notably,four key mutations(A5G,F267Y,Y324I and Q370R)were detected in all isolates,and one novel mutation(I447M)was detected in three CPV-2 isolates.These mutations in the CPV-2 strains could impact vaccine efcacy and the efectiveness of the virus immune evasion.Surprisingly,no recombination events were observed between the identifed CPV-2c strains and reference strains from China.Our data revealed that amino acid residues 324,426 and 440 of VP2 may under strong selection pressure.This pattern of genetic variation in the CPV-2 lineage warrants continuous laboratory-based surveillance programs in other parts of China to better understand the pattern of seasonal distribution and association between emerging genotypes and the intensity of disease severity.
文摘Objective:To assess the association between X-ray repair cross-complementating group 1 (XRCC1) polymorphisms and pancreatic cancer.Methods:We searched MEDLINE,Web of Science and HuGE Navigator at June 2010,and then quantitatively summarized associations of the XRCC1 polymorphisms with pancreatic cancer risk using meta-analysis.Results:Four studies with 1343 cases and 2302 controls were included.Our analysis found:at codon 194,the Trp allele did not decrease pancreatic cancer risk (Arg/Arg versus Trp/Trp:OR=0.97;95% CI:0.48-1.96;P=0.97;Arg/Arg versus Arg/Trp:OR=0.89;95% CI:0.70-1.13;P=0.55;Arg/Trp versus Trp/Trp:OR=1.06;95% CI:0.52-2.16;P=0.90);at codon 280,only a study showed a nonsignificant association between single nucleotide polymorphism with pancreatic cancer risk;at codon 399,the Gln allele also showed no signi?cant effect on pancreatic cancer compared to Arg allele (Arg/Arg versus Gln/Gln:OR=0.94;95% CI:0.74-1.18;Arg/Arg versus Arg/Gln:OR=0.97;95% CI:0.83-1.13;Arg/Gln versus Gln/Gln:OR=0.97;95% CI:0.77-1.22).The shape of the funnel plot and the Egger's test did not detect any publication bias.Conclusion:There is no evidence that XRCC1 polymorphisms (Arg194Trp,Arg280His,and Arg399Gln) are associated with pancreatic cancer risk.
文摘The purpose of this work is to study the molecular epiderniological characteristics of norovirus gastroenteritis outbreaks in Guangdong. During October 2003 and December 2004, fecal and anal swabs specimens collected from 13 outbreaks of non-bacterial gastroenteritis were tested for nomvirus. Specimens were detected by RT-PCR and sequenced. The descriptive data were also collected. Eight in 13 outbreaks of gastroenteritis were positive for nomvirus. All of 8 virus strains were identified as genogroup Ⅱ but belonged to 3 genotypes. Six strains were G Ⅱ -4 genotype. Nomvirus is a major cause of outbreaks of nonbacterial gastroenteritis in Guangdong province and has a wide distribution. The illness happended from late autumn to winter. The prevalent strains were genogroup Ⅱ virus.
基金Modern Agri-industry Technology Research System(CARS-43)Science and Technology Innovation Fund of Fujian Academy of Agriculture Science(STIF-02)Science and Technology Innovation Foundation for Young Scientists of Fujian Academy of Agriculture Science(2008QB-6)
文摘Duck circovirus (DuCV), a potential immunosuppressive virus, was investigated in Southern China from March 2006 to December 2009 by using a polymerase chain reaction (PCR) based method. In this study, a total of 138 sick or dead duck samples from 18 different farms were examined with an average DuCV infection rate of-35%. It was found that ducks between the ages of 40~60 days were more susceptible to DuCV. There was no evidence showing that the DuCV virus was capable of vertical transmission. Farms with positive PCR results exhibited no regularly apparent clinical abnormalities such as feathering disorders, growth retardation or lower-than-average weight. The complete genomes of 91 strains from Fujian Province and 1 from Zhejiang Province were sequenced and analyzed. The 10 DuCV genomes, comlbared with others genomes downloaded from GenBank, ranged in size from 1988 to 1996 base pairs, with sequence identities ranging from 83.2% to 99.8%. Phylogenetic analysis based on genome sequences demonstrated that DuCVs can be divided into two distinct genetic genotypes, Group I (the Euro-USA lineage) and Group II(the Taiwan lineage), with approximately 10.0% genetic difference between the two types. Molecular epidemiological data suggest there is no obvious difference among DuCV strains isolated from different geographic locations or different species, including Duck, Muscovy duck, Mule duck, Cheery duck, Mulard duck and Pekin duck.
基金Supported by the National Natural Science Foundation of China(Nos.31670208,41871037,31800172)the Fund for Shanxi“1331 Project”。
文摘The genus Sheathia consists of over 20 species primarily distributed in Asia,Europe,Oceania,North America,and Africa.However,the origin and evolution of this genus remain unclear.Two gametophyte stage specimens(SAS18052 and SAS18523)and two“Chantransia”stage specimens(YTS19161 and YTS19017)were collected from Shanxi and Henan Provinces in China,respectively.Based on morphological data,isolates YTS19161 and YTS19017 were similar to Audouinella pygmaea,whereas the morphological characteristics of SAS18052 and SAS18523 were in good agreement with the circumscription description of S.longipedicellata.Molecular sequences of rbc L,COI-5P,and psb A were used to investigate the phylogenetic,evolutionary,and biogeographic origin of the genus Sheathia.The three molecular markers supported that the two gametophyte stage specimens belong to S.longipedicellata,while the isolates YTS19161 and YTS19017 were the“Chantransia”of S.longipedicellata.Ancestral area reconstruction and divergence time estimation speculated that Sheathia originated in North America,a portion of the Pangaea at approximately 328.07-184.73 million years ago(Ma).Our relaxed molecular clock analysis suggests that the Florideophyceae diverged approximately 741.04(894.36-631.70)Ma.The major divergences in this class involved the emergence of Nemaliophycidae[ca.662.01(779.83-580.51)Ma],and the split of orders Batrachospermales and Thoreales[ca.456.10(552.80-367.88)Ma].
基金financially supported by the National Natural Science Foundation of China (81874339)Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences (2022-I2M-1-018).
文摘Objective:This work aimed to report the first complete mitochondrial genome(mitogenome)of Rheum palmatum,summarize the features of Caryophyllales mitogenomes,and to reveal the potential of utilizing the mitogenomes of R.palmatum and other Caryophyllales species for inferring phylogenetic relationships and species identification.Methods:Both Illumina short reads and PacBio HiFi reads were utilized to obtain a complete mitogenome of R.palmatum.A variety of bioinformatics tools were employed to characterize the R.palmatum mitogenome,compare the reported mitogenomes in Caryophyllales and conduct phylogenetic analysis.Results:The mitogenome of R.palmatum was assembled into a single master circle of 302,993 bp,encoding 35 known protein-coding genes,18 transfer RNA genes,and three ribosome RNA genes.A total of 249 long repeats and 49 simple sequence repeats were identified in this mitogenome.The sizes of mitogenomes in Caryophyllales varied from 253 kb to 11.3 Mb.Among them,23 mitogenomes were circular molecules,one was linear,and one consisted of relaxed circles,linear molecules,and supercoiled DNA.Out of the total mitogenomes,11 were single-chromosome structure,whereas the remaining 14 were multi-chromosomal organizations.The phylogenetic analysis is consistent with both the Engler system(1964)and the Angiosperm Phylogeny Group III system.Conclusions:We obtained the first mitogenome of R.palmatum,which consists of a master circle.Mitogenomes in Caryophyllales have variable genome sizes and structures even within the same species.Circular molecules are still the dominant pattern in Caryophyllales.Single-chromosome mitogenomes account for nearly a half of all the mitogenomes in Caryophyllales,in contrast to previous studies.It is feasible to utilize mitochondrial genomes for inferring phylogenetic relationships and conducting species identification.
文摘In this study, we report that we successfully cloned and sequenced a chitinase gene from the ovotestis of Kuroda’s sea hare Aplysia kurodai. By using reverse transcription-polymerase chain reaction (RT-PCR) and a system for the 5’ and 3’ rapid amplification of cDNA ends, we obtained a 1352 bp chitinase gene (AkChi) from the ovotestis of A. kurodai. AkChi contains a 1263 bp open reading frame that encodes 421 amino acids. The domain structure predicted from the deduced amino acid sequence was an N-terminal signal peptide and a catalytic domain of glycoside hydrolase (GH) family 18 chitinase. A comparative analysis of the deduced amino acid sequences of AkChi with those of the acidic mammalian chitinase of the California sea hare Aplysia californica revealed the highest homology at 83%. The purified chitinase from the ovotestis was digested by trypsin, and 119 residues of digested peptides were consistent with the deduced amino acid sequence of AkChi. We used RT-PCR to evaluate the expression of AkChi in various tissues of A. kurodai, and we observed that AkChi was expressed only in the ovotestis. A phylogenetic tree analysis, performed using the amino acid sequences of AkChi and known GH family 18 chitinases, showed that AkChi was separated from the molluscan chitinases with a chitin binding domain. To our knowledge, this is the first study demonstrating the cDNA cloning of an ovotestis chitinase from a sea hare.
基金supported by the China Agriculture Research System of MOF and MARA(CARS-08)the Scientific Innovation Program of the Chinese Academy of Agricultural Sciences。
文摘Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.