High prevalence of blaCTX-M and blaSHV among ESBL producing E. coli isolates from beef cattle in China's Sichuan-Chongqing Circle.

Enterobacteria that produce extended-spectrum ß-lactamase (ESBL) such as Escherichia coli (E. coli) are common in our environment and known to cause serious health implications in humans and animals. ß-lactam antibiotics such as penicillins, cephalosporins and monobactams are the most commonly used anti-bacterials in both humans and animals, however, Gram negative bacteria (such as E. coli) that produces extended-spectrum ß-lactamases (ESBLs) have the ability to hydrolyze most ß-lactams therefore making them resistant to ß-lactam antibiotics. Recent extensive researches on the epidemiology and genetic characteristics of extended-spectrum ß-lactamase (ESBL)-producing E. coli reported the existence of ESBL-producing E. coli in humans, companion animals and poultry. Therefore, this experiment was performed to investigate the prevalence and genetic characteristics of ß-lactamase producing E. coli isolated from beef cattle farms in the Sichuan-Chongqing circle of China. Phenotypic confirmation of ESBL-producing E. coli was performed using the double disk synergy test. Polymerase Chain Reaction (PCR) was used to detect blaCTX-M, blaSHV and blaTEM gene codes, then after, isolates were divided into different phylogenetic groups and multi-locus sequence typing (MLST). The results showed that out of the 222 E. coli strains isolated from the beef cattle, 102 strains showed ESBL phenotypes. The PCR results showed that blaCTX-M was the predominant ESBL gene identified among the E. coli strains with 21 (9.5%) isolates having this gene, followed by blaSHV which was found in 18 (8.1%) isolates. The majority of these ESBL positive isolates were assigned to phylogroup A (19.8%) followed by phylogroup B1 (13.5%). In addition, from the MLST results on ESBL positive isolates (n = 30) we identified 19 STs, ST398 (ST398cplx) and ST7130 which were the prevalent population (20%). In conclusion, the high prevalence of CTX-M, and SHV in the study confirmed its association with E. coli infection; therefore, this calls for health concerns on ESBL-producing E. coli. As far as we know, this is the first comprehensive research report relating to ESBL-producing E. coli incidence in Chinese beef cattle.

Draft Genome Sequence of Serratia marcescens Strain ZZCCN01, Isolated from the Cardiac Blood of a Beef Cow.

Serratia marcescens strain ZZCCN01 was isolated from the cardiac blood of a dead beef cow with a lung infection and a foam-like secretion from the nostril. Here, we introduce the 5.1-Mb draft genome sequence, which comprises 105 scaffolds, and the corresponding annotation.

Comparative iTRAQ Proteomics Reveals Multiple Effects of Selenium Yeast on Dairy Cows in Parturition.

The effects of prepartum dietary supplementation with selenium yeast on low abundant plasma proteins in postpartum dairy cows are not known. In this study, 24 healthy parturient dairy cows were divided into two groups (group C, a control group, and group T, a selenium treatment group). Low abundance proteins were extracted from plasma samples of calving cows, and 542 proteins were identified by isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis. Dietary supplementation with selenium yeast caused differential abundance of 48 proteins with a fold change of more than 1.2 or less than 0.83 (p < 0.05); 14 proteins were upregulated and 34 were downregulated. The top five gene ontology (GO) enrichment terms for the differentially expressed proteins were protein homotetramerization (or tetramerization), defense response to bacteria or fungus, acute-phase reactions, nucleotide catabolic process, and positive regulation of lipid metabolic process. All proteins involved in acute-phase reactions were downregulated, indicating that selenium ameliorates systemic inflammation. The vast majority of proteins involved in the defense response to microorganisms were downregulated, thereby affecting innate immunity. The decreased abundance of apolipoprotein A-I and apolipoprotein C-II, critical proteins for positive regulation of lipid metabolism, indicated that selenium may optimize lipid metabolism. The iTRAQ results showed that prenatal supplementation with yeast selenium can relieve systemic inflammation after parturition. Moreover, selenium may reduce the effects of metabolic diseases, which can improve glyconeogenesis and prevent ketosis and fatty liver.

Genome-wide DNA methylation profile of prepubertal porcine testis.

The biological structure and function of the mammalian testis undergo important developmental changes during prepuberty and DNA methylation is dynamically regulated during testis development. In this study, we generated the first genome-wide DNA methylation profile of prepubertal porcine testis using methyl-DNA immunoprecipitation (MeDIP) combined with high-throughput sequencing (MeDIP-seq). Over 190 million high-quality reads were generated, containing 43642 CpG islands. There was an overall downtrend of methylation during development, which was clear in promoter regions but less so in gene-body regions. We also identified thousands of differentially methylated regions (DMRs) among the three prepubertal time points (1 month, T1; 2 months, T2; 3 months, T3), the majority of which showed decreasing methylation levels over time. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that many genes in the DMRs were linked with cell proliferation and some important pathways in porcine testis development. Our data suggest that DNA methylation plays an important role in prepubertal development of porcine testis, with an obvious downtrend of methylation levels from T1 to T3. Overall, our study provides a foundation for future studies and gives new insights into mammalian testis development.

[Resistin: It's role in insulin resistance and mechanism of action].

Resistin is a new adipokine found in vivo in recent years. Recent studies have indicated that resistin contributes to the development of insulin resistance and type 2 diabetes mellitus (T2DM) and mediates inflammatory reaction via different signal pathways. As a signal factor between inflammation and metabolism, resistin is expected to provide new insights for the treatment of insulin resistance and T2DM. However, because specific receptor of resistin has not been identified in the body so far, the molecular mechanism of resistin actions is still unclear. In this article, we review the latest progresses of resistin study, especially the role of resistin in insulin resistance and its signaling mechanism.

[Full-length genome analysis of four genotype 3 letogenic Newcastle disease viruses isolated from different hosts].

The purpose of this study is trying to analysis the homology between four lentogenic Class I genotype 3 Newcastle disease virus isolates from different hosts with NDV strain NDV 08-004, which was the first obtained complete genome sequence virus of class I genotype 3. The full-length genome of NDV isolates, JS/3/09/Ch, ZJ/3/10/Ch, AH/2/10/Du and JS/9/08/Go,were determined by RT-PCR and then an alyzed. All the genomes are 15 198 nucleotides (nt) in length. Compared with the full genome sequences of Class II NDV stains (genotype IV-IX),four isolates has a 6-nt deletion in the non-coding region of nuclear phosphoprotein gene between nucleotides 1 640-1 641 and 12-nt insertion in the coding region of phospho protein gene between nucleotides 2 381-2 382. All the isolates have the motifs 112EQ/RQE/GRL117 at the cleavage site of the fusion protein, which is typical of lenogenic NDV strains, and it is in agreement with the result of pathogenic tests. The full-length genome of 4 genotype 3 NDV isolates shared 93% nucleotide identity with NDV08-004. The results of alignment of 6 viral genes showed that NP gene shared the highest identity (98.3%-96.4%) and P gene shared the lowest identity (96.1%-91.9%). The results show the following two points. First, it is concluded that the isolates from different hosts share the same genotype has the insignificant divergence in the genetic information. Second, it is proposed that the mutation rates of NP/F/L genes are lower than P/M/HN genes.

[Cloning of alpha-bungarotoxin gene and its prokaryotic expression as a non-fusion protein].

On the basis of the reported amino acid sequence of alpha-bungarotoxin (alpha-BGT), DNA sequence of alpha-BGT was deduced and fourteen partially complementary oligonucleotides were designed and synthesized. A plasmid carrying the coding region of alpha-BGT was obtained by primer extension, PCR and ligation with pMD-18-T. The target fragment was digested with Xba I and EcoR I, recovered and ligated with pET28a(+). The resultant expression vector was transformed into BL21 (DE3), BL21 (DE3) Codon plus, and BL21 (DE3) plysS, respectively. Recombinant alpha-BGT was expressed in BL21 (DE3) and was analyzed by 15% Tris/tricine SDS-PAGE. The result showed that the recombinant protein, mostly found in inclusion bodies, accounted for 11.98% of the total bacterial lysate. The expression capacity could be increased to 16.28% by optimizing expression conditions. Western blotting results showed that the expressed protein had similar immunogenicity with the natural alpha-BGT protein purified from the venom of Krait Bungarus spp. In vivo toxicity assay of purified and renatured proteins in mice showed that LD50 was about 1.28 microg/g.