Early social contact alters the community structure and functions of the faecal microbiome in suckling-growing piglets.

Social contact during suckling, in an enriched social environment, can reduce the aggressive behaviours of piglets during regrouping at weaning, and improve their production performance and welfare. The aim of this study was to determine the possible impact of suckling social contact on gut microbes. We performed 16S rRNA sequencing to measure the faecal microbial structure and function in piglets experiencing social contact. Eighteen-litter piglets were allocated to two treatments: an early continuous social contact (CSC) group where piglets from adjacent pens shared a mutual pen starting at 14 days postpartum and a control (CON) group where piglets had no contact with individuals from adjacent pens during the suckling period. The piglets were regrouped at 36 days of age. The litter weights at 35 and 63 days of age were measured. Faecal samples were randomly collected at 16, 35, 42, and 63 days of age and faecal DNA was determined. The results showed that the litter weight of piglets in the CSC group was significantly decreased at 63 days compared with the CON group. Continuous social contact also significantly decreased the microbial richness at 16 and 35 days of age (P < 0.05). Firmicutes was the most abundant bacterial phylum in both groups at all detected time-points and the abundance increased with social contact. At the genus level, Lactobacillus was the most abundant bacterium after weaning and the abundance increased in the piglets with social contact. Compared with the faecal microbiota of control piglets, a total of 22 genera at 16 days, 20 genera at 35 days, 12 genera at 42 days, and 27 genera at 63 days in the faeces of CSC piglets were observed to be significantly different in abundance (linear discriminant analysis score > 3, P < 0.05). Furthermore, functional analysis of the microbial composition showed that the changes induced by early CSC mainly altered the relative abundance of metabolic and related pathways. The social contact notably had an effect on the abundance of microbial pathways for amino acid and carbohydrate metabolism. In conclusion, CSC changed the microbial composition in the faeces of piglets, which might have a negative effect on nutrient metabolism for the suckling-growing piglets. Our study provided new insight into the influence of social contact on the suckling-growing piglets.

Exploring rat plasmatic proteomes: what triggered the liver regeneration?

To further clarify the priming mechanism of liver regeneration, proteins and protein complexes from rat plasma (normal group, partial hepatectomy (PHx) group and sham-operation group) were comparatively studied by two-dimensional gel electrophoresis and two-dimensional blue native gel electrophoresis. Our results suggested that Kupffer cell--NF-kappaB/ROS might trigger the liver regeneration.

[A new melanoma antigen-encoding gene subfamily in human chromosome X].

A lot of studies have been focused on the tumor-related genes. We have cloned a new melanoma antigen-encoding gene (MAGE) from human fetal liver of third trimester and subsequently found that it represented a new MAGE gene subfamily, named MAGE-D. The MAGE-D subfamily contained three orthologs including human MAGE-D1, rat SNERG-1 and mouse DLXIN-1, and two paralogs including human MAGE-D and human KIAA1114. All human members of MAGE-D subfamily are located in human chromosome Xp11.21-p11.23. Moreover, MAGE-D subfamily stands out from other known subfamilies MAGE-A, -B and -C of MAGE family in view of typical features such as exon/intron organization, absence of tumorspecific antigens, evolutionarily divergent in sequences. The identification of MAGE-D subfamily will be helpful in understanding the genesis of tumor.

[Isolation of specific expression gene in human fetal liver by representational difference analysis].

AIM: To isolate specific gene expressed in human fetal liver tissue and find out genes with important biological functions. METHODS: mRNA obtained from 4-months human fetus liver tissue was used as tester, and mRNA obtained from adult liver tissue was used as driver, and representational difference analysis (RDA) was performed. The subtracted final product was subcloned into the pGEM-T easy vector, after transformation, bacterial colonies were randomly picked, and 54 plasmid clones with inserts were purified and sequenced. The homology search of genes was performed by online-based BLAST program through the nonredundant and EST database at Nation Center of Biotechnology Information (NCBI), the expression pattern of novel gene was further verified by competitive PCR. RESULTS: Marker with alpha-globin gene family, its expression frequency in subtractive cDNA pool is 7 times than non-subtractive cDNA library, and the pool contains many genes closely relative with liver growth. These show that RDA is an effective method to isolate gene differential expression. Through sequencing some clones, we get two sequences not reported before. CONCLUSION: The library is a useful means to study genes expressed specially in fetal liver.

[Isolation of regulation genes related with liver regeneration by representational difference analysis].

mRNA isolated from 2/3 partially hepatectomied rats was used as a tester for representational difference analysis (RDA). The subtracted tester cDNA was cloned into a T vector and a rat regeneration liver specific EST pool was constructed, which contained about 30000 independent clones. A sequence analysis of 52 clones randomly picked up from this pool indicated that the liver regeneration specific sequences were enriched, and the results of RNA blots revealed some novel genes in association with liver regeneration.