To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1(DHAV-1) isolates,the virulence,cross neutralization assays and the complete ...To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1(DHAV-1) isolates,the virulence,cross neutralization assays and the complete sequence of the virion protein 1(VP1) gene of nine virulent DHAV-1 strains,which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008,were tested.The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses(ELD 50 s) and the median lethal doses(LD 50 s),respectively.The results showed that the ELD 50 s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10 6 /mL to 1.44 × 10 7 /mL,while the LD 50 s were 2.39 × 10 5 /mL to 6.15 × 10 6 /mL.Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates,respectively.Compared with other virulent,moderate virulent,attenuated vaccine and mild strains,the VP1 genes of the 9 strains shared 89.8%-99.7% similarity at the nucleotide level and 92.4%-99.6% at amino acid level with other DHAV-1 strains.There were three hypervariable regions at the C-terminus(aa 158-160,180-193 and 205-219) and other variable points in VP1 protein,but which didn't cause virulence of DHAV-1 change.展开更多
Dear Editor,Duck virus hepatitis(DVH)is caused by at least threedifferent RNA viruses,including duck hepatitis A virus(DHAV),duck astrovirus type 1(DAstV-1),and duckastrovirus type 2(DAstV-2).The first of these,DHAV,h...Dear Editor,Duck virus hepatitis(DVH)is caused by at least threedifferent RNA viruses,including duck hepatitis A virus(DHAV),duck astrovirus type 1(DAstV-1),and duckastrovirus type 2(DAstV-2).The first of these,DHAV,has been classified into three serotypes by展开更多
Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinnin...Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinning represents a disturbance, which likely affects belowground organisms and may feed back to stand productivity.However, the impact of CTT on the belowground food web is poorly understood. Since nematodes are species-rich and abundant belowground organisms, occupying a variety of trophic positions in soil food webs and being sensitive to disturbances, they serve as ecological indicators of ecosystem disturbance.Results:We studied the effect of CTT on the soil nematode community structure in pine (Pinus massoniana Lamb.),Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and cypress (Cupressus funebris Endl.) plantations in the Sichuan Basin three years after applying CTT. Crop-tree thinning significantly increased the abundance of soil nematodes in each of the plantations. Moreover, CTT significantly increased the relative abundance of herbivorous nematodes in each of the plantations. Furthermore, CTT increased the proportion of stress tolerators (c-p 1)and enrichment opportunists (c-p 2) and reduced the maturity, structure and enrichment indices of nematodes in Chinese fir and cypress plantations, while only subtle changes were observed in pine plantations. Interestingly,across plantations, the effects of CTT on soil nematode communities were mainly due to changes in microbial biomass nitrogen and understory vegetation diversity.Conclusions:Forest management practices resulting in more open canopies uniformly affect soil food webs by changing the quantity and quality of resources associated with increased understory cover and diversity as well as microbial food. These insights increase our understanding of the impacts of forest management on the structure and functioning of belowground communities, which may contribute to management and conservation policies for more sustainable forestry.展开更多
Collembola,a common pest of mushrooms,could reduce the yield and quantity of edible mushroom and causes great economic losses in their production.During the investigation of Collembola in the main edible mushroom prod...Collembola,a common pest of mushrooms,could reduce the yield and quantity of edible mushroom and causes great economic losses in their production.During the investigation of Collembola in the main edible mushroom production areas in China,27 species belonging to five families and 16 genera,hosted by more than ten species of edible mushrooms have been revealed by morphological and molecular evidence.The most diverse genus was the genus Ceratophysella with five species reported.Fourteen of the 27 species were distributed only in China,while others were widely distributed all over the world.Fifteen species on mushrooms have been barcoded;the results of the species delimitation by mitochondrial COI marker confirmed the results by morphology,with low intra-specific divergences(0-8%).Two Thalassaphorura species,with the only difference being in the presence of parapseudocelli on the anterior ventral head,were clearly differentiated by the molecular markers.展开更多
基金the Chinese National Natural Sciences Foundation(30871878)Shandong Province Higher Educational Science and Technology Program(J08LF07)the Science and Technology Commission of Shandong Province(2010GNC10914),China
文摘To investigate the relationship of the variation of virulence and the external capsid proteins of the pandemic duck hepatitis A virus type 1(DHAV-1) isolates,the virulence,cross neutralization assays and the complete sequence of the virion protein 1(VP1) gene of nine virulent DHAV-1 strains,which were isolated from infected ducklings with clinical symptoms in Shandong province of China in 2007-2008,were tested.The fifth generation duck embryo allantoic liquids of the 9 isolates were tested on 12-day-old duck embryos and on 7-day-old ducklings for the median embryonal lethal doses(ELD 50 s) and the median lethal doses(LD 50 s),respectively.The results showed that the ELD 50 s of embryonic duck eggs of the 9 DHAV-1 isolates were between 1.9 × 10 6 /mL to 1.44 × 10 7 /mL,while the LD 50 s were 2.39 × 10 5 /mL to 6.15 × 10 6 /mL.Cross-neutralization tests revealed that the 9 DHAV-1 isolates were completely neutralized by the standard serum and the hyperimmune sera against the 9 DHAV-1 isolates,respectively.Compared with other virulent,moderate virulent,attenuated vaccine and mild strains,the VP1 genes of the 9 strains shared 89.8%-99.7% similarity at the nucleotide level and 92.4%-99.6% at amino acid level with other DHAV-1 strains.There were three hypervariable regions at the C-terminus(aa 158-160,180-193 and 205-219) and other variable points in VP1 protein,but which didn't cause virulence of DHAV-1 change.
基金funded by grants from the Shandong Modern Agricultural Technology & Industry System(SDAIT-13-011-15)the Science and Technology Commission of Shandong Province(2010GNC10914),China
文摘Dear Editor,Duck virus hepatitis(DVH)is caused by at least threedifferent RNA viruses,including duck hepatitis A virus(DHAV),duck astrovirus type 1(DAstV-1),and duckastrovirus type 2(DAstV-2).The first of these,DHAV,has been classified into three serotypes by
基金supported by the National Key Research and Development Program of China (Grant No. 2017YFD060030205)the German Government loans for Sichuan Forestry Sustainable Management (Grant No. G1403083)the“Tianfu Ten Thousand Talents Plan”of Sichuan Province (Grant No. 1922999002). the financial support from the China Scholarship Council (Project No. 202006910045)
文摘Background:Crop-tree thinning (CTT) is a forest management practice aiming at enhancing the growth of target trees in plantations by harvesting neighboring trees. Along with the positive effect on tree growth, thinning represents a disturbance, which likely affects belowground organisms and may feed back to stand productivity.However, the impact of CTT on the belowground food web is poorly understood. Since nematodes are species-rich and abundant belowground organisms, occupying a variety of trophic positions in soil food webs and being sensitive to disturbances, they serve as ecological indicators of ecosystem disturbance.Results:We studied the effect of CTT on the soil nematode community structure in pine (Pinus massoniana Lamb.),Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) and cypress (Cupressus funebris Endl.) plantations in the Sichuan Basin three years after applying CTT. Crop-tree thinning significantly increased the abundance of soil nematodes in each of the plantations. Moreover, CTT significantly increased the relative abundance of herbivorous nematodes in each of the plantations. Furthermore, CTT increased the proportion of stress tolerators (c-p 1)and enrichment opportunists (c-p 2) and reduced the maturity, structure and enrichment indices of nematodes in Chinese fir and cypress plantations, while only subtle changes were observed in pine plantations. Interestingly,across plantations, the effects of CTT on soil nematode communities were mainly due to changes in microbial biomass nitrogen and understory vegetation diversity.Conclusions:Forest management practices resulting in more open canopies uniformly affect soil food webs by changing the quantity and quality of resources associated with increased understory cover and diversity as well as microbial food. These insights increase our understanding of the impacts of forest management on the structure and functioning of belowground communities, which may contribute to management and conservation policies for more sustainable forestry.
基金The present study was mainly supported by funding from the National Natural Science Foundation of China(41571052,41811530086)the Science and Technology Development Plan Project of Jilin Province(20160520051JH)+1 种基金the Postdoctoral Science Foundation of China(2015M570281)the funding provided by the Alexander von Humboldt Foundation,and the academic exchange program between Chinese and Polish Academies of Sciences.
文摘Collembola,a common pest of mushrooms,could reduce the yield and quantity of edible mushroom and causes great economic losses in their production.During the investigation of Collembola in the main edible mushroom production areas in China,27 species belonging to five families and 16 genera,hosted by more than ten species of edible mushrooms have been revealed by morphological and molecular evidence.The most diverse genus was the genus Ceratophysella with five species reported.Fourteen of the 27 species were distributed only in China,while others were widely distributed all over the world.Fifteen species on mushrooms have been barcoded;the results of the species delimitation by mitochondrial COI marker confirmed the results by morphology,with low intra-specific divergences(0-8%).Two Thalassaphorura species,with the only difference being in the presence of parapseudocelli on the anterior ventral head,were clearly differentiated by the molecular markers.
