Wolbachia are maternally inherited endosymbiotic bacteria infecting a wide range of arthropods and filarial nematodes. They can induce various reproduction alterations in their hosts, including thelytokous parthenogen...Wolbachia are maternally inherited endosymbiotic bacteria infecting a wide range of arthropods and filarial nematodes. They can induce various reproduction alterations in their hosts, including thelytokous parthenogenesis, cytoplasmic incompatibility (CI), feminization of genetic males and male killing. Here we investigated diversity and prevalence patterns of Wolbachia infection in 43 geographical populations of the Asian corn borer, Ostriniafurnacalis, in China and one population in North Korea. Based on Wolbachia surface protein gene (wsp) sequences, nine strains of Wolbachia (wFurl-wFur9), belonging to supergroups A and B, were identified in populations of O. furnacalis with an average infection rate of 10.5%. Superinfection commonly appeared in individuals of O. furnacalis and coinfection patterns were very complex. There was no specific pattern for the prevalence and distribution of the nine Wolbachia strains suggesting an intricate evolutionary history of Wolbachia infection in this species. The genetic similarity of the wFurl-wFur9 strains with those detected in two parasitoids of O. furnacalis, Macrocentrus cingulum and Lydella grisescens, strongly suggests host-parasitoid horizontal transmission.展开更多
BACKGROUND The recent rise in the incidence of hepatitis B virus(HBV)infections in a densely populated city of eastern India(“mixing vessel”of people of varied socioeconomic and immune status)prompted this study.App...BACKGROUND The recent rise in the incidence of hepatitis B virus(HBV)infections in a densely populated city of eastern India(“mixing vessel”of people of varied socioeconomic and immune status)prompted this study.Applying saliva on fingers for enumerating bank notes is a common practice in the Indian subcontinent.Paper notes may be a potential source of“horizontal”transmission of this virus,especially if there are cuts/bruises on the oral mucous membrane or skin.AIM To investigate whether paper currencies could be a plausible mode of horizontal transmission of HBV infection.METHODS Polymerase chain reactions(PCR)followed by nucleotide sequencing was done for the detection of HBV.Hepatitis B virus surface antigen enzyme-linked immunosorbent assay(HBsAg ELISA)was performed on all HBV deoxyribonucleic acid-positive samples to check the detectability of the virus.Atomic force microscopy(AFM)was carried out for visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings.RESULTS HBV-specific PCRs on pellets obtained after ultracentrifugation/immunoprecipitation of the currency paper washings detected potentially intact/viable HBV(genotype D2)in 7.14%of samples(n=70).AFM gave the visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings.However,HBV isolates from the currency notes could not be detected by HBsAg ELISA.CONCLUSION It is a common practice in the Indian subcontinent to count paper currencies by applying saliva on fingertips.Paper notes may be a potential source of“horizontal”transmission of this virus,especially if there are cuts/bruises on the oral mucous membrane or skin,but it was practically not possible to demonstrate experimentally such transmission.Detection of potentially intact/viable and“occult”HBV from currency poses potential risk of silent transmission of this virus among the general population.展开更多
In this paper, a class of discrete vertical and horizontal transmitted disease model under constant vaccination is researched. Under the hypothesis of population being constant size, the model is transformed into a pl...In this paper, a class of discrete vertical and horizontal transmitted disease model under constant vaccination is researched. Under the hypothesis of population being constant size, the model is transformed into a planar map and its equilibrium points and the corresponding eigenvalues are solved out. By discussing the influence of coefficient parameters on the eigenvalues, the hyperbolicity of equilibrium points is determined. By getting the equations of flows on center manifold, the direction and stability of the transcritical bifurcation and flip bifurcation are discussed.展开更多
A robust SEIR epidemic disease model with a profitless delay and vertical transmission is formulated, and the dynamics behaviors of the model under pulse vaccination are analyzed. By use of the discrete dynamical syst...A robust SEIR epidemic disease model with a profitless delay and vertical transmission is formulated, and the dynamics behaviors of the model under pulse vaccination are analyzed. By use of the discrete dynamical system determined by the stroboscopic map, an ‘infection-free' periodic solution is obtained, further, it is shown that the ‘infection-free' periodic solution is globally attractive when some parameters of the model are under appropriate conditions. Using the theory on delay functional and impulsive differential equation, the sufficient condition with time delay for the permanence of the system is obtained, and it is proved that time delays, pulse vaccination and vertical transmission can bring obvious effects on the dynamics behaviors of the model. The results indicate that the delay is ‘profitless’.展开更多
This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type...This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type influences the dissemination of mcr.We collected 673 samples from humans(rectal normal flora),poultry,and the environment(water,flies,birds,etc.)in Vientiane,Lao People’s Democratic Republic(Laos),from May to September 2018.A total of 238 Escherichia coli(E.coli)isolated from nonduplicative samples,consisting of 98 MCR-positive E.coli(MCRPEC)("mcr"denotes the gene encoding mobile colistin resistance,and"MCR"denotes the subsequent protein encoded by mcr)and 140 MCRnegative E.coli(MCRNEC),were characterized by phenotype and Illumina sequencing.A subset of MCRPEC was selected for Min ION sequencing,conjugation assay,plasmid stability,and growth kinetics in vitro.The prevalence of MCRPEC was found to be 14.6%(98/673),with the highest prevalence in human rectal swabs(45.9%(45/98),p<0.0001,odds ratio(OR):0.125,95% confidence interval(CI):0.077-0.202).The percentages of MCRPEC from other samples were 14.3%(2/14)in dog feces,12.0%(24/200)in flies,11.0%(11/100)in chicken meat,8.9%(8/90)in chicken cloacal,8.0%(4/50)in chicken caeca,and 7.5%(4/53)in wastewater.MCRPEC was significantly more resistant to co-amoxiclav,sulfamethoxazoletrimethoprim,levofloxacin,ciprofloxacin,and gentamicin than MCRNEC(p<0.05).Genomic analysis revealed the distribution of MCRPEC among diverse clonal types.The putative plasmid Inc types associated with mcr-1 were Inc X4,Inc HI2,Inc P1,Inc I2,and Inc FIA,and those associated with mcr-3 were Inc FII,Inc FIA,Inc FIB,Inc P1,and Inc R.Recovery of highly similar plasmids from both flies and other sampling sectors implied the role of flies in the dissemination of mcr-1.mcr-positive plasmids were shown to be conjugative,and a significantly high transfer rate into a hypervirulent clone ST1193 was observed.Plasmids containing mcr irrespective of Inc type were highly stable and invariably did not exert a fitness effect upon introduction into a new host.These findings signify the urgent need for a standard infection control program to radically decontaminate the source of resistance.展开更多
In this paper, a deterministic mathematical model for the spread of HIV/AIDS in a variable size population through horizontal transmission is considered. The existence of a threshold parameter, the basic reproduction ...In this paper, a deterministic mathematical model for the spread of HIV/AIDS in a variable size population through horizontal transmission is considered. The existence of a threshold parameter, the basic reproduction number, is established, and the stability of both the disease-free equilibrium and the endemic equilibrium is discussed in terms of R0 .展开更多
Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as thi...Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as this ant species spread from its South America origin to other parts of the globe. The wsp gene of Wolbachia was analyzed using the WSP Typing and a similarity analysis was conducted to analyse the sharing of the symbiont among nests of S. invicta ants. The analyses revealed the presence of two groups of Wolbachia: strain A belonging to InvA S. invicta subgroup, and the strain B belonging to Acromyrmex insinuator. The wsp gene and its hypervariable regions are shared among the Wolbachia present in different types of ants inhabiting in the New World. Wolbachia strains found in the nests of S. invicta are ant-specialist symbionts which may have spread by several means among the ant population.展开更多
Mycoviruses have been found to infect more than 12 species of Penicillium,but have not been isolated from Penicillium italicum(P.italicum).In this study,we isolated and characterized a new double-stranded RNA(dsRNA)vi...Mycoviruses have been found to infect more than 12 species of Penicillium,but have not been isolated from Penicillium italicum(P.italicum).In this study,we isolated and characterized a new double-stranded RNA(dsRNA)virus,designated Penicillium italicum chrysovirus 1(PiCVl),from the citrus pathogen P.italicum HSPi-YNl.Viral genome sequencing and molecular characterization indicated that PiCV 1 was highly homologous to the previously described Penicillium chrysogenum virus.We further constructed the mutant HSPi-YNl ApksP defective in the polyketide synthase gene(pksP),which is involved in pigment biosynthesis,and these mutants formed albino(white)colonies.Then we applied hyphal anastomosis method to horizontally transmit PiCV 1 from the white virus-donors(i.e.,HSPi-YNl mutants)to wild-type recipients(i.e.,P.italicum strains HSPi-CQ54,HSPi-HB4,and HSPi-HNl),and the desirable PiCV 1-infected isogenic recipients,a certain part of blue wild-type strains,can be eventually selected and confirmed by viral genomic dsRNA profile analysis.This bluewhite colony screening would be an easier method to select virus-infected P.italicum recipients,according to distinguishable color phenotypes between blue virus-recipients and white virus-donors.In summary,the current work newly isolated and characterized PiCVl,verified its horizontal transmission among dually cultured P.italicum isolates,and based on these,established an effective and simplified approach to screen PiCV 1-infected isogenic recipients.展开更多
Wolbachia are endosymbiotic bacteria that infect numerous arthropod species. Previous studies in Panama and Australia revealed that the majority of fig wasp species harbor Wolbachia infections, but that similar patter...Wolbachia are endosymbiotic bacteria that infect numerous arthropod species. Previous studies in Panama and Australia revealed that the majority of fig wasp species harbor Wolbachia infections, but that similar patterns of incidence have evolved inde- pendently with different wasp species and Wolbachia strains on the two continents. We found Wolbachia infections in 25/47 species (53%) of fig wasp associated with 25 species of Chinese figs. Phylogenetic analyses of Wotbachia wsp sequences indicated that very similar strains are not obviously found in either closely related or ecologically linked fig wasps species. The extremely high prevalence of Wolbachia in fig wasps (over 50% of species infected) is not constrained by geographical origin and is a recurrent theme of fig wasp/Wolbachia interactions.展开更多
基金funded by China Agriculture Research System(CARS-02)
文摘Wolbachia are maternally inherited endosymbiotic bacteria infecting a wide range of arthropods and filarial nematodes. They can induce various reproduction alterations in their hosts, including thelytokous parthenogenesis, cytoplasmic incompatibility (CI), feminization of genetic males and male killing. Here we investigated diversity and prevalence patterns of Wolbachia infection in 43 geographical populations of the Asian corn borer, Ostriniafurnacalis, in China and one population in North Korea. Based on Wolbachia surface protein gene (wsp) sequences, nine strains of Wolbachia (wFurl-wFur9), belonging to supergroups A and B, were identified in populations of O. furnacalis with an average infection rate of 10.5%. Superinfection commonly appeared in individuals of O. furnacalis and coinfection patterns were very complex. There was no specific pattern for the prevalence and distribution of the nine Wolbachia strains suggesting an intricate evolutionary history of Wolbachia infection in this species. The genetic similarity of the wFurl-wFur9 strains with those detected in two parasitoids of O. furnacalis, Macrocentrus cingulum and Lydella grisescens, strongly suggests host-parasitoid horizontal transmission.
基金Supported by Institutional Grant by Council of Scientific and Industrial Research-Indian Institute of Chemical Biology,Kolkata,No.MLP-118。
文摘BACKGROUND The recent rise in the incidence of hepatitis B virus(HBV)infections in a densely populated city of eastern India(“mixing vessel”of people of varied socioeconomic and immune status)prompted this study.Applying saliva on fingers for enumerating bank notes is a common practice in the Indian subcontinent.Paper notes may be a potential source of“horizontal”transmission of this virus,especially if there are cuts/bruises on the oral mucous membrane or skin.AIM To investigate whether paper currencies could be a plausible mode of horizontal transmission of HBV infection.METHODS Polymerase chain reactions(PCR)followed by nucleotide sequencing was done for the detection of HBV.Hepatitis B virus surface antigen enzyme-linked immunosorbent assay(HBsAg ELISA)was performed on all HBV deoxyribonucleic acid-positive samples to check the detectability of the virus.Atomic force microscopy(AFM)was carried out for visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings.RESULTS HBV-specific PCRs on pellets obtained after ultracentrifugation/immunoprecipitation of the currency paper washings detected potentially intact/viable HBV(genotype D2)in 7.14%of samples(n=70).AFM gave the visual confirmation of HBV particles in ultracentrifuged/immunoprecipitated samples from currency paper washings.However,HBV isolates from the currency notes could not be detected by HBsAg ELISA.CONCLUSION It is a common practice in the Indian subcontinent to count paper currencies by applying saliva on fingertips.Paper notes may be a potential source of“horizontal”transmission of this virus,especially if there are cuts/bruises on the oral mucous membrane or skin,but it was practically not possible to demonstrate experimentally such transmission.Detection of potentially intact/viable and“occult”HBV from currency poses potential risk of silent transmission of this virus among the general population.
文摘In this paper, a class of discrete vertical and horizontal transmitted disease model under constant vaccination is researched. Under the hypothesis of population being constant size, the model is transformed into a planar map and its equilibrium points and the corresponding eigenvalues are solved out. By discussing the influence of coefficient parameters on the eigenvalues, the hyperbolicity of equilibrium points is determined. By getting the equations of flows on center manifold, the direction and stability of the transcritical bifurcation and flip bifurcation are discussed.
基金the National Natural Science Foundation of China(No.10471117)
文摘A robust SEIR epidemic disease model with a profitless delay and vertical transmission is formulated, and the dynamics behaviors of the model under pulse vaccination are analyzed. By use of the discrete dynamical system determined by the stroboscopic map, an ‘infection-free' periodic solution is obtained, further, it is shown that the ‘infection-free' periodic solution is globally attractive when some parameters of the model are under appropriate conditions. Using the theory on delay functional and impulsive differential equation, the sufficient condition with time delay for the permanence of the system is obtained, and it is proved that time delays, pulse vaccination and vertical transmission can bring obvious effects on the dynamics behaviors of the model. The results indicate that the delay is ‘profitless’.
基金funded partly by the Wellcome Trust(214207/Z/18/Z)。
文摘This study was designed to investigate the molecular epidemiology of mobile colistin resistance(mcr)using a"One-Health"approach in Laos and to predict whether any dominant plasmid backbone and/or strain type influences the dissemination of mcr.We collected 673 samples from humans(rectal normal flora),poultry,and the environment(water,flies,birds,etc.)in Vientiane,Lao People’s Democratic Republic(Laos),from May to September 2018.A total of 238 Escherichia coli(E.coli)isolated from nonduplicative samples,consisting of 98 MCR-positive E.coli(MCRPEC)("mcr"denotes the gene encoding mobile colistin resistance,and"MCR"denotes the subsequent protein encoded by mcr)and 140 MCRnegative E.coli(MCRNEC),were characterized by phenotype and Illumina sequencing.A subset of MCRPEC was selected for Min ION sequencing,conjugation assay,plasmid stability,and growth kinetics in vitro.The prevalence of MCRPEC was found to be 14.6%(98/673),with the highest prevalence in human rectal swabs(45.9%(45/98),p<0.0001,odds ratio(OR):0.125,95% confidence interval(CI):0.077-0.202).The percentages of MCRPEC from other samples were 14.3%(2/14)in dog feces,12.0%(24/200)in flies,11.0%(11/100)in chicken meat,8.9%(8/90)in chicken cloacal,8.0%(4/50)in chicken caeca,and 7.5%(4/53)in wastewater.MCRPEC was significantly more resistant to co-amoxiclav,sulfamethoxazoletrimethoprim,levofloxacin,ciprofloxacin,and gentamicin than MCRNEC(p<0.05).Genomic analysis revealed the distribution of MCRPEC among diverse clonal types.The putative plasmid Inc types associated with mcr-1 were Inc X4,Inc HI2,Inc P1,Inc I2,and Inc FIA,and those associated with mcr-3 were Inc FII,Inc FIA,Inc FIB,Inc P1,and Inc R.Recovery of highly similar plasmids from both flies and other sampling sectors implied the role of flies in the dissemination of mcr-1.mcr-positive plasmids were shown to be conjugative,and a significantly high transfer rate into a hypervirulent clone ST1193 was observed.Plasmids containing mcr irrespective of Inc type were highly stable and invariably did not exert a fitness effect upon introduction into a new host.These findings signify the urgent need for a standard infection control program to radically decontaminate the source of resistance.
基金partly supported by NSF (201115043) of Jilin Province
文摘In this paper, a deterministic mathematical model for the spread of HIV/AIDS in a variable size population through horizontal transmission is considered. The existence of a threshold parameter, the basic reproduction number, is established, and the stability of both the disease-free equilibrium and the endemic equilibrium is discussed in terms of R0 .
基金the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior(CAPES)for the financial support to the first author
文摘Wolbachia is a bacterium that infects many arthropods with horizontal or vertical transmission. The introduction and spreading of Solenopsis invicta in new areas may have influenced the acquisition of Wolbachia as this ant species spread from its South America origin to other parts of the globe. The wsp gene of Wolbachia was analyzed using the WSP Typing and a similarity analysis was conducted to analyse the sharing of the symbiont among nests of S. invicta ants. The analyses revealed the presence of two groups of Wolbachia: strain A belonging to InvA S. invicta subgroup, and the strain B belonging to Acromyrmex insinuator. The wsp gene and its hypervariable regions are shared among the Wolbachia present in different types of ants inhabiting in the New World. Wolbachia strains found in the nests of S. invicta are ant-specialist symbionts which may have spread by several means among the ant population.
基金supported by the National Natural Science Foundations of China (No. 31371893)the Natural Science Fund of Hubei Province (No. 2018CFB676)the Project of Hubei Key Laboratory of Genetic Regulation and Integrative Biology (Grant No. GRIB20184)
文摘Mycoviruses have been found to infect more than 12 species of Penicillium,but have not been isolated from Penicillium italicum(P.italicum).In this study,we isolated and characterized a new double-stranded RNA(dsRNA)virus,designated Penicillium italicum chrysovirus 1(PiCVl),from the citrus pathogen P.italicum HSPi-YNl.Viral genome sequencing and molecular characterization indicated that PiCV 1 was highly homologous to the previously described Penicillium chrysogenum virus.We further constructed the mutant HSPi-YNl ApksP defective in the polyketide synthase gene(pksP),which is involved in pigment biosynthesis,and these mutants formed albino(white)colonies.Then we applied hyphal anastomosis method to horizontally transmit PiCV 1 from the white virus-donors(i.e.,HSPi-YNl mutants)to wild-type recipients(i.e.,P.italicum strains HSPi-CQ54,HSPi-HB4,and HSPi-HNl),and the desirable PiCV 1-infected isogenic recipients,a certain part of blue wild-type strains,can be eventually selected and confirmed by viral genomic dsRNA profile analysis.This bluewhite colony screening would be an easier method to select virus-infected P.italicum recipients,according to distinguishable color phenotypes between blue virus-recipients and white virus-donors.In summary,the current work newly isolated and characterized PiCVl,verified its horizontal transmission among dually cultured P.italicum isolates,and based on these,established an effective and simplified approach to screen PiCV 1-infected isogenic recipients.
文摘Wolbachia are endosymbiotic bacteria that infect numerous arthropod species. Previous studies in Panama and Australia revealed that the majority of fig wasp species harbor Wolbachia infections, but that similar patterns of incidence have evolved inde- pendently with different wasp species and Wolbachia strains on the two continents. We found Wolbachia infections in 25/47 species (53%) of fig wasp associated with 25 species of Chinese figs. Phylogenetic analyses of Wotbachia wsp sequences indicated that very similar strains are not obviously found in either closely related or ecologically linked fig wasps species. The extremely high prevalence of Wolbachia in fig wasps (over 50% of species infected) is not constrained by geographical origin and is a recurrent theme of fig wasp/Wolbachia interactions.