Dong Xinlin The Zouxian Yedian cemetery is a rather typical remains of the Dawenkou culture. The present paper, grounded on the definite stratigraphical relationship known through the author’s study, attempt to make ...Dong Xinlin The Zouxian Yedian cemetery is a rather typical remains of the Dawenkou culture. The present paper, grounded on the definite stratigraphical relationship known through the author’s study, attempt to make a typological analysis of the unearthed high-shaped cup, fu - cauldron- shaped ding tripod, bowl-shaped ding , jar-shaped ding, gui tripod, flask, high-stemmed cup with pierced work, dish-shaped den stemmed vessel, bowl-shaped den and fled-mouth carinate-rim he, so as to put foe typological sequences of the vessels on a stratiguaphical background. On ibis basis the Yedian tombs are preliminarily divided into 9 groups and 5 phases, thus detailed chronology is es tablished. These phases roughly cover the periods which the tombs so far known in the Dawenkou culture belong to, and can be taken as a lather reliable standard scale. They roughly parallel the stages from the Yangshao to the MiaodiguⅡ culture in the Central Plains.展开更多
To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyz...To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyzed with DNAStar software. Nucleic acid sequence homology was 97.7%-100%, with 78 mutations observed. Among these 60 clones, the sequences of 17 clones were identical and recognized as the dominant quasispecies of strain SD0612. Evolution of SD0612 quasispecies diversity under antibody selective pressure was also studied. SD0612 was passed continuously in the Marc-145 cell line over 40 passages in 6 independent lineages. SD0612 antiserum was not added to lineage A, B, and C cultures; however, antiserum was added to culture medium for lineages D, E, and F. PRRSV ORF5 was then amplified, cloned, and sequenced from each of the 6 lineages, designated as A40-F40. F40 was further passed in Marc-145 cells using 6 independent lineages with or without F40 antiserum for another 40 passages. ORF5 from the 6 newly-derived virus lineages, which we designated as a40-f40, were amplified, cloned and sequenced. The proportion of dominant quasispecies increased with passage number in cell cultures supplemented with antibodies, but decreased when antibodies were lacking. Our work has demonstrated a diversity of quasispecies for ORF5 in PRRSV SD0612. Antibody selective pressure was able to significantly influence quasispecies diversity and promote a dominant quasispecies that was able to evade immune reactions.展开更多
Recent outbreaks of Zika virus （ZIKV） infections in Oceania＇s islands and the Americas were characterized by high numbers of cases and the spread of the virus to new areas. To better understand the origin of ZIKV, ...Recent outbreaks of Zika virus （ZIKV） infections in Oceania＇s islands and the Americas were characterized by high numbers of cases and the spread of the virus to new areas. To better understand the origin of ZIKV, its epidemic history was reviewed. Although the available records and information are limited, two major genetic lineages of ZIKV were identified in previous studies. However, in this study, three lineages were identified based on a phylogenetic analysis of all virus sequences from GenBank, including those of the envelope protein （E） and non-structural protein 5 （NS5） coding regions. The spatial and temporal distributions of the three identified ZIKV lineages and the recombination events and mechanisms underlying their divergence and evolution were further elaborated. The potential migration pathway of ZIKV was also characterized. Our findings revealed the central roles of two African countries, Senegal and Cote d＇lvoire, in ZIKV evolution and genotypic divergence. Furthermore, our results suggested that the outbreaks in Asia and the Pacific islands originated from Africa. The results provide insights into the geographic origins of ZlKV outbreaks and the spread of the virus, and also contribute to a better understanding of ZlKV evolution, which is important for the prevention and control of ZlKV infections.展开更多
文摘Dong Xinlin The Zouxian Yedian cemetery is a rather typical remains of the Dawenkou culture. The present paper, grounded on the definite stratigraphical relationship known through the author’s study, attempt to make a typological analysis of the unearthed high-shaped cup, fu - cauldron- shaped ding tripod, bowl-shaped ding , jar-shaped ding, gui tripod, flask, high-stemmed cup with pierced work, dish-shaped den stemmed vessel, bowl-shaped den and fled-mouth carinate-rim he, so as to put foe typological sequences of the vessels on a stratiguaphical background. On ibis basis the Yedian tombs are preliminarily divided into 9 groups and 5 phases, thus detailed chronology is es tablished. These phases roughly cover the periods which the tombs so far known in the Dawenkou culture belong to, and can be taken as a lather reliable standard scale. They roughly parallel the stages from the Yangshao to the MiaodiguⅡ culture in the Central Plains.
文摘To study the quasispecies diversity of porcine reproductive and respiratory syndrome virus (PRRSV), open reading frame 5 (ORF5) of strain SD0612 was amplified and cloned. Sixty clones of ORF5 were sequenced and analyzed with DNAStar software. Nucleic acid sequence homology was 97.7%-100%, with 78 mutations observed. Among these 60 clones, the sequences of 17 clones were identical and recognized as the dominant quasispecies of strain SD0612. Evolution of SD0612 quasispecies diversity under antibody selective pressure was also studied. SD0612 was passed continuously in the Marc-145 cell line over 40 passages in 6 independent lineages. SD0612 antiserum was not added to lineage A, B, and C cultures; however, antiserum was added to culture medium for lineages D, E, and F. PRRSV ORF5 was then amplified, cloned, and sequenced from each of the 6 lineages, designated as A40-F40. F40 was further passed in Marc-145 cells using 6 independent lineages with or without F40 antiserum for another 40 passages. ORF5 from the 6 newly-derived virus lineages, which we designated as a40-f40, were amplified, cloned and sequenced. The proportion of dominant quasispecies increased with passage number in cell cultures supplemented with antibodies, but decreased when antibodies were lacking. Our work has demonstrated a diversity of quasispecies for ORF5 in PRRSV SD0612. Antibody selective pressure was able to significantly influence quasispecies diversity and promote a dominant quasispecies that was able to evade immune reactions.
基金supported by the Science and Technology Basic Work Program(2013FY113500)from the Ministry of Science and Technology of China
文摘Recent outbreaks of Zika virus （ZIKV） infections in Oceania＇s islands and the Americas were characterized by high numbers of cases and the spread of the virus to new areas. To better understand the origin of ZIKV, its epidemic history was reviewed. Although the available records and information are limited, two major genetic lineages of ZIKV were identified in previous studies. However, in this study, three lineages were identified based on a phylogenetic analysis of all virus sequences from GenBank, including those of the envelope protein （E） and non-structural protein 5 （NS5） coding regions. The spatial and temporal distributions of the three identified ZIKV lineages and the recombination events and mechanisms underlying their divergence and evolution were further elaborated. The potential migration pathway of ZIKV was also characterized. Our findings revealed the central roles of two African countries, Senegal and Cote d＇lvoire, in ZIKV evolution and genotypic divergence. Furthermore, our results suggested that the outbreaks in Asia and the Pacific islands originated from Africa. The results provide insights into the geographic origins of ZlKV outbreaks and the spread of the virus, and also contribute to a better understanding of ZlKV evolution, which is important for the prevention and control of ZlKV infections.
