Fecal Microbiota Succession of Piglets from Birth to Post-weaning by 454 Pyrosequencing Analysis

The objective of this study was to describe the fecal microbiota succession of piglets from birth to postweaning by pyrosequencing.The dominant bacterial phyla were Bacteroidetes,Firmicutes,Proteobacteria,and Fusobacteria,although the composition of the fecal microbiota changed as the piglets grew.Bacteroides,Parabacteroides,Prevotella,Lactobacillus,unclassified Lachnospiraceae,Ruminococcus,Oscillospira,Phascolarctobacterium,and Desulfovibrio were the core genera in the feces of piglets and existed from birth to post-weaning.Bacteroides was the most abundant at birth; however,the proportion of Bacteroides decreased as the piglets aged,while the proportion of Prevotella increased until it became the most abundant genus at the post-weaning stage.Principal coordinate analysis indicated that the microbial communities of piglet fecal samples from birth to postweaning could be separated into four groups according to the similarity of community composition.These corresponded to time points on day 0 (birth); day 7; days 14,21,and 28 (pre-weaning); and day 35 (post-weaning).This study suggests that the development of the intestinal microbiota in the piglet is a gradual and sequential process.This methodology establishes a basis for broader studies to investigate the microbiota of the piglet intestinal tract.

Effects of soil fauna on leaf litter decomposition under different land uses in eastern coast of China

Soil fauna decompose litter, whereas land use changes may significantly alter the composition and structure of soil fauna assemblages. However, little is known of the effects of land-use on the contribution of soil fauna to litter decomposition. We studied the impacts of soil fauna on the decomposition of litter from poplar trees under three different land uses （i.e. poplar-crop integrated system, poplar plantation, and cropland）, from December 2013 to December 2014, in a coastal area of Northern Jiangsu Province. We collected litter samples in litterbags with three mesh sizes （5, 1 and 0. 01 mm, respectively） to quantify the contribution of various soil fauna to the decomposition of poplar leaf litter. Litter decomposition rates differed significantly by land use and were highest in the cropland, intermediate in the poplar-crop integrated system, and lowest in the poplar plantation. Soil fauna in the poplar-crop integrated system was characterized by the highest numbers of taxa and individuals, and highest Margalef＇s diversity, which suggested that agro-forestry ecosystems may support a greater quantity, distribution, and biodiversity of soil fauna than can single-species agriculture or plantation forestry. The individuals and groups of soil fauna in the macro-mesh litterbags were higher than in the meso-mesh litterbags underthe same land use types. The average contribution rate of meso- and micro-fauna to litter decomposition was 18.46%, which was higher than the contribution rate of macro-fauna （3.31%）. The percentage of remaining litter mass was inversely related to the density of the soil fauna （P 〈 0.05） in poplar plantations; however, was unrelated in the poplar-crop integrated system and cropland. This may have been the result of anthropogenic interference in poplar-crop integrated systems and croplands. Our study suggested that when land-use change alters vegetation types, it can affect species composition and the structure of soil fauna assemblages, which, in turn, affects litter decomposition.

Trehalose-6-phosphate phosphatases are involved in trehalose synthesis and metamorphosis in Bactrocera minax

Trehalose is the principal sugar circulating in the hemolymph of insects,and trehalose synthesis is catalyzed by trehalose-6-phosphate synthase(TPS)and trehalose-6-phosphate phosphatase(TPP).Insect TPS is a fused enzyme containing both TPS do-main and TPP domain.Thus,many insects do not possess TPP genes as TPSs have re-placed the function of TPPs.However,TPPs are widely distributed across the dipteran insects,while the roles they play remain largely unknown.In this study,3 TPP genes from notorious dipteran pest Bactrocera minax(BmiTPPB,BmiTPPCl,and BmiTPPC2)were identified and characterized.The different temporal-spatial expression patterns of 3 BmiTPPs implied that they exert different functions in B.minax.Recombinant BmiTPPs were heterologously expressed in yeast cells,and all purified proteins exhibited enzy-matic activities,despite the remarkable disparity in performance between BmiTPPB and BmiTPPCs.RNA interference revealed that all BmiTPPs were successfully downregulated after double-stranded RNA injection,leading to decreased trehalose content and increased glucose content.Also,suppression of BmiTPPs significantly affected expression of down-stream genes and increased the mortality and malformation rate.Collectively,these results indicated that all 3 BmiTPPs in B.minax are involved in trehalose synthesis and metamor-phosis.Thus,these genes could be evaluated as insecticidal targets for managing B.minax,andevenforotherdipteranpests.