Porcine bocavirus(PBoV)is a single-stranded DNA virus,belongs to the genus Bocaparvovirus of family Parvoviridae.It was discovered along with porcine circovirus 2(PCV 2)and torque tenovirus(TTV)in the lymph nodes of p...Porcine bocavirus(PBoV)is a single-stranded DNA virus,belongs to the genus Bocaparvovirus of family Parvoviridae.It was discovered along with porcine circovirus 2(PCV 2)and torque tenovirus(TTV)in the lymph nodes of pigs suffering from postweaning multisystemic wasting syndrome(PMWS)in Sweden in 2009.PBoV has been reported throughout the world,mostly in weaning piglets,and has a broad range of tissue tropism.Since PBoV is prevalent in healthy as well as clinically infected pigs and is mostly associated with coinfection with other viruses,the pathogenic nature of PBoV is still unclear.Currently,there are no cell lines available for the study of PBoV,and animal model experiments have not been described.This review summarizes the current state of knowledge about PBoV,including the epidemiology,evolution analysis,detection methods,pathogenesis and public health concerns.展开更多
The gene RB is derived from the wild potato species S. bulbocastanum and confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to investigate whether a single stra...The gene RB is derived from the wild potato species S. bulbocastanum and confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to investigate whether a single strain of P. infestans can adapt to overcome this partial resistance source, we subjected RB containing leaflets to multiple rounds of infection with P. infestans, with a culture isolated from a lesion used to infect the next leaflet (a passage). A parallel line of passages was done using susceptible leaflets as hosts. At the end of the experiment, P. infestans strains passaged through resistant or susceptible leaflets were compared for infection efficiency and lesion size. Variants of the P. infestans effector family IPI-O, some of which are recognized by the RB protein to elicit resistance, were cloned and sequenced to determine whether variation occurred during selection on the partially resistant host. Our results show that after 20 rounds of selection, no breakdown in RB resistance took place. In fact, the strain that was continually passaged through the partially resistant host produced smaller lesions on susceptible leaflets and had a lower infection frequency than the strain passaged through susceptible cultivar Katahdin. No changes within IPI-O coding regions were detected after selection on the hosts with RB. Our results indicate that individual strains of P. infestans are not capable of rapidly overcoming RB resistance even when it is the only host available.展开更多
AB_(5)-type toxins are a group of secreted protein toxins that are central virulence factors for bacterial pathogens such as Shigella dysenteriae,Vibrio cholerae,Bordetella pertussis,and certain lineages of pathogenic...AB_(5)-type toxins are a group of secreted protein toxins that are central virulence factors for bacterial pathogens such as Shigella dysenteriae,Vibrio cholerae,Bordetella pertussis,and certain lineages of pathogenic Escherichia coli and Salmonella enterica.AB_(5) toxins are composed of an active(A)subunit that manipulates host cell biology in complex with a pentameric binding/delivery(B)subunit that mediates the toxin’s entry into host cells and its subsequent intracellular trafficking.Broadly speaking,all known AB_(5)-type toxins adopt similar structural architectures and employ similar mechanisms of binding,entering and trafficking within host cells.Despite this,there is a remarkable amount of diversity amongst AB_(5)-type toxins;this includes different toxin families with unrelated activities,as well as variation within families that can have profound functional consequences.In this review,we discuss the diversity that exists amongst characterized AB_(5)-type toxins,with an emphasis on the genetic and functional variability within AB_(5) toxin families,how this may have evolved,and its impact on human disease.展开更多
[Objectives]This study was conducted to clarify the species,occurrence and distribution characteristics of sugarcane rust pathogens in low-latitude plateau sugarcane rust areas of Yunnan Province and the phylogenetic ...[Objectives]This study was conducted to clarify the species,occurrence and distribution characteristics of sugarcane rust pathogens in low-latitude plateau sugarcane rust areas of Yunnan Province and the phylogenetic relationship between the pathogens and that between them and other rust fungi of the genus Puccinia.[Methods]Fifty seven sugarcane rust samples collected from the sugarcane areas of Baoshan,Lincang,Menghai,Menglian,Ximeng,Lancang and Wenshan in Yunnan were subjected to molecular identification.[Results]The four sugarcane rust samples from Haiyin1 hao in Menghai,Yunnan Province belonged to orange rust of sugarcane,and the pathogen was Puccinia kuehnii Butler.;and other 53 samples of sugarcane rust belonged to brown rust of sugarcane,and the pathogen was Puccinia melanocephala Syd.et P.Syd.The rDNA sequences of other rust fungi from the genus Puccinia were downloaded from GenBank and used for the construction of an NJ tree for systematic evolution analysis together with the sequences obtained in this study.The results showed that the four P.kuehnii sequences obtained in this study were clustered with Puccinia polysora(GenBank accession number:GU058024)into one group,and they were close genetically;the 53 P.melanocephala sequences were clustered with P.nakanishikii(GenBank accession number:GU058002),P.rufipes(GenBank accession number:AJ296545),Aecidium deutziae(GenBank accession number:KU309317)and P.coronata(GenBank accession number:DQ354526)into one group,and they had a close genetic relationship;and the genetic relationship of the two species of sugarcane rust fungi identified in this study was relatively distant.[Conclusions]This study provides a scientific basis for sugarcane rust epidemic prediction,disease resistance breeding,and precise prevention and control.展开更多
动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolu...动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)筛选得到具有高亲和力和高特异性的功能性单链寡核苷酸。本文结合国内外研究,阐述了核酸适体的优势以及其在人工养殖动物病原微生物防控中的研究进展,同时重点讨论了核酸适体在应用方面的5种挑战,(1)核酸适体筛选技术的局限性;(2)核酸适体在治疗方面缺乏稳定性与安全性;(3)核酸适体在生物体内如何持续性发挥靶向治疗作用;(4)核酸适体在活体实验中的精确性有待提高;(5)核酸适体与其他检测方法能否串联,从而构建全面性的检测平台。目前核酸适体针对养殖动物病原领域的研究只是刚刚起步,在快速检测与靶向治疗方面具有广阔的应用前景。展开更多
基金the support from the Organization for Women in Science for the Developing World (OWSD) and the Swedish International Developmentfinancially supported by the National Key R&D Program of China (2016YFD0500103)partly by China Central Public-interest Scientific Institution Basal Research Fund (1610312020020)。
文摘Porcine bocavirus(PBoV)is a single-stranded DNA virus,belongs to the genus Bocaparvovirus of family Parvoviridae.It was discovered along with porcine circovirus 2(PCV 2)and torque tenovirus(TTV)in the lymph nodes of pigs suffering from postweaning multisystemic wasting syndrome(PMWS)in Sweden in 2009.PBoV has been reported throughout the world,mostly in weaning piglets,and has a broad range of tissue tropism.Since PBoV is prevalent in healthy as well as clinically infected pigs and is mostly associated with coinfection with other viruses,the pathogenic nature of PBoV is still unclear.Currently,there are no cell lines available for the study of PBoV,and animal model experiments have not been described.This review summarizes the current state of knowledge about PBoV,including the epidemiology,evolution analysis,detection methods,pathogenesis and public health concerns.
文摘The gene RB is derived from the wild potato species S. bulbocastanum and confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to investigate whether a single strain of P. infestans can adapt to overcome this partial resistance source, we subjected RB containing leaflets to multiple rounds of infection with P. infestans, with a culture isolated from a lesion used to infect the next leaflet (a passage). A parallel line of passages was done using susceptible leaflets as hosts. At the end of the experiment, P. infestans strains passaged through resistant or susceptible leaflets were compared for infection efficiency and lesion size. Variants of the P. infestans effector family IPI-O, some of which are recognized by the RB protein to elicit resistance, were cloned and sequenced to determine whether variation occurred during selection on the partially resistant host. Our results show that after 20 rounds of selection, no breakdown in RB resistance took place. In fact, the strain that was continually passaged through the partially resistant host produced smaller lesions on susceptible leaflets and had a lower infection frequency than the strain passaged through susceptible cultivar Katahdin. No changes within IPI-O coding regions were detected after selection on the hosts with RB. Our results indicate that individual strains of P. infestans are not capable of rapidly overcoming RB resistance even when it is the only host available.
基金supported by a start-up grant provided by the Uni-versity of Alberta Faculty of Science(to C.C.F.)a Natural Sciences and Engineering Research Council of Canada(NSERC)Discovery Grant(Grant number:RGPIN-2020-03964 to C.C.F.).
文摘AB_(5)-type toxins are a group of secreted protein toxins that are central virulence factors for bacterial pathogens such as Shigella dysenteriae,Vibrio cholerae,Bordetella pertussis,and certain lineages of pathogenic Escherichia coli and Salmonella enterica.AB_(5) toxins are composed of an active(A)subunit that manipulates host cell biology in complex with a pentameric binding/delivery(B)subunit that mediates the toxin’s entry into host cells and its subsequent intracellular trafficking.Broadly speaking,all known AB_(5)-type toxins adopt similar structural architectures and employ similar mechanisms of binding,entering and trafficking within host cells.Despite this,there is a remarkable amount of diversity amongst AB_(5)-type toxins;this includes different toxin families with unrelated activities,as well as variation within families that can have profound functional consequences.In this review,we discuss the diversity that exists amongst characterized AB_(5)-type toxins,with an emphasis on the genetic and functional variability within AB_(5) toxin families,how this may have evolved,and its impact on human disease.
基金Supported by China Agriculture Research System of MOF and MARA(CARS-170303)Joint Special Project of Basic Agricultural Research in Yunnan Province(2018FG001-029)+1 种基金"Yunling Industrial Technology Leading Talents"Training Project(2018LJRC56)Special Fund for the Construction of Modern Agricultural Industry Technology System in Yunnan Province(YNGZTX-4-92)。
文摘[Objectives]This study was conducted to clarify the species,occurrence and distribution characteristics of sugarcane rust pathogens in low-latitude plateau sugarcane rust areas of Yunnan Province and the phylogenetic relationship between the pathogens and that between them and other rust fungi of the genus Puccinia.[Methods]Fifty seven sugarcane rust samples collected from the sugarcane areas of Baoshan,Lincang,Menghai,Menglian,Ximeng,Lancang and Wenshan in Yunnan were subjected to molecular identification.[Results]The four sugarcane rust samples from Haiyin1 hao in Menghai,Yunnan Province belonged to orange rust of sugarcane,and the pathogen was Puccinia kuehnii Butler.;and other 53 samples of sugarcane rust belonged to brown rust of sugarcane,and the pathogen was Puccinia melanocephala Syd.et P.Syd.The rDNA sequences of other rust fungi from the genus Puccinia were downloaded from GenBank and used for the construction of an NJ tree for systematic evolution analysis together with the sequences obtained in this study.The results showed that the four P.kuehnii sequences obtained in this study were clustered with Puccinia polysora(GenBank accession number:GU058024)into one group,and they were close genetically;the 53 P.melanocephala sequences were clustered with P.nakanishikii(GenBank accession number:GU058002),P.rufipes(GenBank accession number:AJ296545),Aecidium deutziae(GenBank accession number:KU309317)and P.coronata(GenBank accession number:DQ354526)into one group,and they had a close genetic relationship;and the genetic relationship of the two species of sugarcane rust fungi identified in this study was relatively distant.[Conclusions]This study provides a scientific basis for sugarcane rust epidemic prediction,disease resistance breeding,and precise prevention and control.
文摘动物疫病的暴发不仅造成了巨大损失,也严重阻碍着人工养殖业的健康可持续发展,因此亟须针对疫病病原开发快速检测技术和病原防控技术来预防病害的暴发。核酸适体(aptamer)是针对特定靶标,利用指数富集配基系统进化技术(systematic evolution of ligands by exponential enrichment,SELEX)筛选得到具有高亲和力和高特异性的功能性单链寡核苷酸。本文结合国内外研究,阐述了核酸适体的优势以及其在人工养殖动物病原微生物防控中的研究进展,同时重点讨论了核酸适体在应用方面的5种挑战,(1)核酸适体筛选技术的局限性;(2)核酸适体在治疗方面缺乏稳定性与安全性;(3)核酸适体在生物体内如何持续性发挥靶向治疗作用;(4)核酸适体在活体实验中的精确性有待提高;(5)核酸适体与其他检测方法能否串联,从而构建全面性的检测平台。目前核酸适体针对养殖动物病原领域的研究只是刚刚起步,在快速检测与靶向治疗方面具有广阔的应用前景。
