Ganqiu Lan

Trancriptomic profiling revealed the signatures of acute immune response in tilapia (Oreochromis niloticus) following Streptococcus iniae challenge

Streptococcus iniae is the most significant bacterial disease of tilapia throughout the world, and commonly leads to tremendous economic losses. In contrast to other important fish species, our knowledge about the molecular mechanisms of tilapia in response to bacterial infection is still limited. Here, therefore, we utilized RNA-seq to first profiling of host responses in tilapia spleen following S. iniae infection at transcriptome level. A total of 223 million reads were obtained and assembled into 192,884 contigs with average length 844 bp. Gene expression analysis between control and infected samples at 5 h, 50 h, and 7 d revealed 1475 differentially expressed genes. In particular, the differentially expressed gene set was dramatically induced as early as 5 h, and rapidly declined to basal levels at 50 h. Enrichment and pathway analysis of the differentially expressed genes revealed the centrality of the pathogen attachment and recognition, cytoskeletal rearrangement and immune activation/inflammation in the pathogen entry and host inflammatory responses. Understanding of these responses can highlight mechanisms of tilapia host defense, and expand our knowledge of teleost immunology. Our findings will set a foundation of valuable biomarkers for future individual, strain, and family-level studies to evaluate immune effect of vaccine and individual response in host defense mechanisms to S. iniae infection, to select disease resistant families and strains.

Milk fat globule is an alternative to mammary epithelial cells for gene expression analysis in buffalo

Owing to the difficulty in obtaining mammary gland tissue from lactating animals, it is difficult to test the expression levels of genes in mammary gland. The aim of the current study was to identify if milk fat globule (MFG) in buffalo milk was an alternative to mammary gland (MG) and milk somatic cell (MSC) for gene expression analysis. Six buffalos in late lactation were selected to collect MFG and MSC, and then MG was obtained by surgery. MFG was stained with acridine orange to successfully visualise RNA and several cytoplasmic crescents in MFG. The total RNA in MFG was successfully isolated and the integrity was assessed by agarose gel electrophoresis. We analysed the cellular components in MFG, MG and MSC through testing the expression of cell-specific genes by qRT-PCR. The results showed that adipocyte-specific gene (AdipoQ) and leucocyte-specific genes (CD43, CSF1 and IL1α) in MFG were not detected, whereas epithelial cell marker genes (Keratin 8 and Keratin 18) in MFG were higher than in MSC and lower than in MG, fibroblast marker gene (vimentin) in MFG was significantly lower than in MG and MSC, milk protein genes (LALBA, BLG and CSN2) and milk fat synthesis-related genes (ACC, BTN1A1, FABP3 and FAS) in MFG were higher than in MG and MSC. In conclusion, the total RNA in MFG mainly derives from mammary epithelial cells and can be used to study the functional gene expression of mammary epithelial cells.

Comparative analysis on liver transcriptome profiles of different methods to establish type 2 diabetes mellitus models in Guangxi Bama mini-pig

AIMS/INTRODUCTION Streptozotocin (STZ) is a permanent diabetogenic compound and often used in animal diabetes modeling. The aim of this study is to compare the liver transcriptome of type 2 diabetes models (T2DM) in Guangxi Bama Mini-pig (GBM pig) induced by STZ or Non-STZ. RESEARCH DESIGN AND METHODS 22 female GBM pigs were divided into 4 groups. Ctr group (4 pigs): standard diets; DM1_HH group (10 pigs): high fat and high carbohydrate diets; DM2_HS group (4 pigs): high fat and high carbohydrate diets + STZ; DM3_SH group (4 pigs): STZ + high fat and high carbohydrate diets. Fasting blood glucose (FBG), fasting insulin (FINS), triglyceride (TG) and total cholesterol (TC) were measured monthly. Glucose disappearance rate was evaluated by intravenous glucose tolerance test (IVGTT). Three pigs liver samples as biological replicates in each group were used for transcriptome sequencing analysis. RESULTS All pigs injected with STZ were identified as diabetic. But only 4 of 10 pigs in DM1_HH group met the diabetes model standard. The most severe insulin resistance was observed in DM2_HS group. The FBG of DM1_HH, DM2_HS, DM3_SH and Ctr group were 7.20 ± 0.17, 14.13 ± 0.45, 7.98 ± 0.99 and 4.43 ± 0.27 mmol/L, respectively; the FINS were 53.67 ± 1.82, 33.38 ± 2.32, 49.91 ± 1.50 and 39.78 ± 1.14 mU/L, respectively. Compared with DM1_HH group, liver transcriptome showed that 7 genes were up-regulated while 10 were down-regulated in DM2_HS, 16 genes were up-regulated while 14 were down-regulated in DM3_SH. There were 4 co-expressive genes in DM2_HSvsDM1_HH and DM3_SHvsDM1_HH, including cystein rich 61 gene (CYR61), ribosomal protein L15 gene (RPL15), regulator of G protein signaling 1 gene (RGS1) and LOC102166695 gene. CONCLUSION STZ can rapidly induce T2DM model in GBM pig, but STZ caused abnormal expression of genes in the liver.

iTRAQ and PRM-based quantitative proteomics in T2DM-susceptible and -tolerant models of Bama mini-pig

Type 2 diabetes mellitus (T2DM) is a complex, multifactorial metabolic disease, and the number of patients with T2DM has continued to increase in recent years. Large-scale proteomic studies on animal models of T2DM are of great importance to understand the pathophysiology of T2DM. Therefore, in our study, Isobaric tags for relative and absolute quantification (iTRAQ) and Parallel reaction monitoring (PRM) were used for proteomic analysis of skeletal muscles from T2DM-susceptible and -tolerant Bama mini-pig models induced by a high-fat, high-sugar diet. In our proteomic analysis, a total of 1646 proteins and 13 differentially expressed proteins (DEPs) were identified by iTRAQ-mass spectrometry, and 6 differentially expressed proteins were validated by PRM. Gene Ontology (GO) analysis revealed that most DEPs were extracellular matrix (ECM) proteins and participated in several biological processes, such as negative regulation of JAK-STAT cascade, negative regulation of STAT cascade, roundabout signaling pathway and peptide cross-linking via chondroitin 4-sulfate glycosaminoglycan, and the molecular functions of roundabout binding, glycosaminoglycan binding, heparin binding, sulfur compound binding, collagen binding, and kinase inhibitor activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis results showed that the differentially expressed proteins were involved in 14 pathways, including human disease pathways, metabolic pathways, signal transduction pathways, signaling molecules and interaction pathways, and the cellular process pathways associated with phagosomes and focal adhesion. In conclusion, the proteomics based on iTRAQ and PRM in T2DM-susceptible and -tolerant Bama mini-pig models showed that changes in amino acid metabolism, inflammation-associated pathways and the impaired function and environment of extracellular matrix are risk factors associated with increased pathogenesis of T2DM in Bama mini-pig.

Comprehensive inbred variation discovery in Bama pigs using de novo assemblies

The Bama mini-pig (BM pig) is an inbred strain of the Bama Xiang pig (BX pig) and an important animal model used for studying human diseases. The extremely long inbreeding period renders a clear distinction between the features of the BM and BX strains, such as in their metabolism and olfactory system. However, there is limited information about differences between BM and BX animals at the genomic level. In this study, we generated genome sequencing data and used the assembly-vs-assembly approach to evaluate the phenotypic variations caused by inbreeding in these strains. Moreover, we detected differential expression of mutant genes related to the phenotypes in BX and BM pigs. We sequenced the genome of the BX pig strain and performed a series of analyses to reveal the comprehensive inbred genetic variants between BX and BM pigs. Here, the 2.56-Gb draft genome assembly for the BX pig and an N50 contig length of approximately 11.87 kb is described, and an N50 scaffold length of approximately 99 kb and the variations in the BX pig genome were identified by comparison with the BM pig reference genome. There were 1,424,354 single nucleotide polymorphisms (SNPs), 2,961,891 insertions and deletions (indels), 13,772 structural variants (SVs), and 20,606 copy number variants (CNVs) identified in the BX genome. Functional annotation of SVs and CNVs showed that the genes (ADGRE2, GPR143, olfactory receptor 52B4-like, olfactory receptor 10H1-like and SHROOM2) with both SVs and CNVs were enriched in the most of all KEGG pathways and gene ontology (GO) terms of mutant genes. ADGRE2, GPR143 and SHROOM2 were both found to have significant higher expression levels in BX pigs than in BM pigs. In the contrary, the expressions of olfactory receptor 52B4-like and olfactory receptor 10H1-like were significant lower in BX pigs than in BM pigs. In conclusion, sequence analysis of the BX pig genome revealed that the genome structure of the two pig strains has considerable genomic variation that was caused by the long inbreeding period. Moreover, qRT-PCR analysis of the mutant genes displayed a significant distinction that may be associated with phenotypic differences between these pig strains.

Assessment of M. longissimus fibre types and metabolic enzymes in Bama miniature pigs and Landrace swine

Abstract Overt differences exist between Chinese local pigs and exotic pig breeds, especially in muscle growth rate and meat quality. However, the underlying molecular mechanisms remain unclear. This study aimed to assess muscle fibre types and metabolic enzymes in Bama miniature pigs and Landrace swine. Meat quality traits, including intramuscular fat content, and muscle colour, conductivity, and tenderness, were assessed in these pig breeds. Then, muscle fibre types were classified, and mRNA amounts and activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and malate dehydrogenase (MDH) assessed, in M. longissimus from the two pig breeds, at various ages. Our data showed significantly higher back fat thickness, muscle conductivity, and intramuscular fat content in samples from Bama miniature pigs compared with the values obtained for Landrace pigs (p < .05). In addition, SDH activity was significantly higher, and LDH activity overtly lower in Bama pigs compared with Landrace swine (p < .05). Furthermore, myosin heavy-chain (MyHC) II A, II B, and II X mRNA levels in Bama miniature pigs at 180 were significantly higher than values obtained for Landrace pigs of the same age. Although MyHC I gene expression levels were similar in Bama miniature and Landrace pigs at 180 days of age, significantly higher amounts were obtained in 300 day old Bama miniature pigs compared with 180 day old Landrace pigs (p < .05). Collectively, these preliminary findings indicated that skeletal muscles from Bama miniature pigs may contain more oxidative fibres compared with those from Landrace pigs, which might explain the meat quality differences between the two pig breeds.