Transcriptome microRNA profiling of bovine mammary glands infected with Staphylococcus aureus.

MicroRNAs are small non-coding RNA molecules that are important regulators of gene expression at the post-transcriptional level. miRNAs impact the processes of cell proliferation, differentiation and apoptosis. Thus, the regulation of miRNA expression profiles associated with mastitis will be conducive for its control. In this study, Staphylococcus aureus (S. aureus) was administered to the mammary gland of Chinese Holstein cows to construct a bacteria-type mastitis model. Total RNA was isolated from bovine mammary gland tissue samples from the S. aureus-induced mastitis group and controls. miRNAs were analyzed using Solexa sequencing and bioinformatics processing for the experimental group and control group. Two miRNA libraries were constructed respectively. A total of 370 known bovine miRNAs and 341 novel mi RNAs were detected for the S. aureus and 358 known bovine miRNAs and 232 novel miRNAs for control groups. A total of 77 miRNAs in the S. aureus group showed significant differences compared to the control group. GO (Gene Ontology) analysis showed these target genes were involved in the regulation of cells, binding, etc., while KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis showed that these genes were enriched in endocytosis, and olfactory transduction pathways involved in cancer. These results provide an experimental basis to reveal the cause and regulatory mechanism of mastitis and also suggest the potential of miRNAs to serve as biomarkers for the diagnosis of mastitis in dairy cows.

Heme oxygenase-2 suppress TNF-α and IL6 expression via TLR4/MyD88-dependent signaling pathway in mouse cerebral vascular endothelial cells.

Heme oxygenase (HO) represents an intrinsic antiinflammatory system based on its ability to inhibit expression of proinflammatory cytokines. The constitutive isoform heme oxygenase-2 (HO-2) has high expression and activity in cerebral microvascular endothelial cells (CMVEC). This study was undertaken to evaluate the role of HO-2 in regulation of TLR4/MyD88-dependent signaling and to study the effect of HO-2 on the expression and secretion of the proinflammatory cytokines tumor necrosis factor α (TNF-α) and Interleukin-6 (IL6) in CMVEC. HO-2 short hairpin RNA (shRNA) and HO-2 overexpression plasmids were used to observe the effect of HO-2 on proinflammatory cytokines in CMVEC in vitro, and the results showed that the messenger RNA (mRNA) and protein levels of TNF-α and IL6 were increased and decreased, respectively, compared with control groups. LPS-stimulated TNF-α and IL6 mRNA and protein were also reduced in CMVEC treated with an inhibitor of TLR4 signaling, CLI-095, or HO-2 overexpression. CLI-095 and HO-2 overexpression both reduced TLR4 expression in CMVEC, and HO-2 shRNA blocked these effects of CLI-095. CLI-095 and HO-2 overexpression potently suppressed TLR4/MyD88-dependent proinflammatory cytokine expression in CMVEC. These results suggest that HO-2 plays an important role in protecting CMVEC against cytokine-mediated inflammation.

[Hexavalent chromium pollution and exposure level in electroplating workplace].

OBJECTIVE: To investigate the pollution of hexavalent chromium in the electroplating workplace and screen the biomarkers of chromium exposure. MATERIAL: Field occupational health investigation was conducted in 25 electroplating workplaces. 157 electroplating workers and 93 healthy unexposed controls were recruited. The epidemiological information was collected with face to face interview. Chromium in erythrocytes was determined by graphite furnace atomic absorption spectrophotometer. RESULTS: The median of short-term exposure concentration of chromium in the air at electroplating workplace was 0.06 mg/m(3) (median) and ranging from 0.01 (detect limit) to 0.53 mg/m(3)). The median concentration of Cr (VI) in erythrocytes in electroplating workers was 4.41 (2.50 ∼ 5.29) µg/L, which was significantly higher than that in control subjects [1.54 (0.61 ∼ 2.98) µg/L, P < 0.01]. After stratified by potential confounding factors such as gender, age, smoking status and alcohol consumption, significant differences still existed between electroplating workers and control subjects, except for the subjects of age less than 30 years old (P = 0.11). CONCLUSION: There was hexavalent chromium pollution in electroplating workplace. Occupational hazards prevention measures should be taken to control the chromium pollution hazards.

Chronic occupational exposure to hexavalent chromium causes DNA damage in electroplating workers.

BACKGROUND: Occupational exposure to chromium compounds may result in adverse health effects. This study aims to investigate whether low-level hexavalent chromium (Cr(VI)) exposure can cause DNA damage in electroplating workers. METHODS: 157 electroplating workers and 93 control subjects with no history of occupational exposure to chromium were recruited in Hangzhou, China. Chromium levels in erythrocytes were determined by graphite furnace atomic absorption spectrophotometer. DNA damage in peripheral lymphocytes was evaluated with the alkaline comet assay by three parameters: Olive tail moment, tail length and percent of DNA in the comet tail (tail DNA%). Urinary 8-OHdG levels were measured by ELISA. RESULTS: Chromium concentration in erythrocytes was about two times higher in electroplating workers (median: 4.41 µg/L) than that in control subjects (1.54 µg/L, P < 0.001). The medians (range) of Olive tail moment, tail length and tail DNA% in exposed workers were 1.13 (0.14-6.77), 11.17 (3.46-52.19) and 3.69 (0.65-16.20), and were significantly higher than those in control subjects (0.14 (0.01-0.39), 3.26 (3.00-4.00) and 0.69 (0.04-2.74), P < 0.001). Urinary 8-OHdG concentration was 13.65 (3.08-66.30) µg/g creatinine in exposed workers and 8.31 (2.94-30.83) µg/g creatinine in control subjects (P < 0.001). The differences of urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA% between these two groups remained significant (P < 0.001) even after stratification by potential confounding factors such as age, gender, and smoking status. Chromium exposure was found to be positively associated with chromium levels in erythrocytes, urinary 8-OHdG levels, Olive tail moment, tail length and tail DNA%. Positive dose-response associations were also found between chromium levels in erythrocytes and Olive tail moment, tail length and tail DNA%. CONCLUSION: The findings in this study indicated that there was detectable chromium exposure in electroplating workers. Low-level occupational chromium exposure induced DNA damage.

[Genetic polymorphism of the IL8 gene and its associations with milk traits and SCS in Chinese Holstein].

The polymorphism of Interleukin-8 (IL8) gene were investigated for 610 Chinese Holstein cows of 30 bull families from a dairy farm in Shanghai using Polymerase Chain Reaction-Single Strand Conformation Polymorphism (PCR-SSCP) technique with a mixed animal model to verify the effects of the polymorphisms on some milk productive performance, tested day milk yield, tested day fat percentage, tested day milk protein percentage, 305 d corrected milk yield, 305 d milk fat yield, 305 d milk protein yield, and somatic cell score (SCS). The aim was to explore the significant molecular marker in practical dairy production. Three genotypes were identified and the genotypic frequencies of KK, KA, and AA were 0.187, 0.451, and 0.362, respectively. The gene frequencies of K and A were 0.412 and 0.588. The results showed highly significant (P < 0.01) association of IL8 mutations with tested day milk yield, 305 d milk protein yield, 305 d corrected milk yield and 305 d milk fat yield, SCS and tested day milk protein percentage (P < 0.05). However, no association (P > 0.05) with tested day milk fat percentage was recorded. The cows with KK genotype had higher tested day milk yield, 305 d milk protein yield, 305 d corrected milk yield and 305 d milk fat yield than those with AA and KA genotypes (P < 0.01). The least square mean of SCS for KK was significantly lower than that with AA and KA genotypes (P < 0.01). AA genotype was significant lower in tested day milk protein percentage than KK and KA genotypes (P < 0.05). The IL8 gene genetic diversity has a great genetic effect on milk traits and mastitis resistance and could be a useful genetic marker for Chinese Holstein breeding.

[Gene flow among sheep breeds of Mongolian group in China].

Gene flow was analyzed among four sheep breeds of Mongolian Group in China using structural gene loci and microsatellite markers.Results showed that genetic differentiation was 0.0164-0.0455 by using structural loci, and was 0.0107-0.0239 by using microsatellite loci.This illustrated that most variations existed within breeds and genetic differentiation level was very low among sheep breeds of Mongolian Group in China.There was substantial Gene flow among the breeds as estimated by the structural loci (Nm=7.971) or the microsatellite method(Nm=15.732).There was no direct relationship between genetic differences from breeds and geographical distances.It is concluded that genetic differentiation of sheep breeds of Mongolian Group in China is mainly the result of natural selection (different living conditions).

[Analysis of genetic co-adaptability of structural loci in Hu sheep].

Using the method of multiloci electrophoresis, genetic co-adaptability of Hu Sheep was analyzed according to allele frequencies in 14 structural loci. The results showed that no co-adaptability existed in the dominance-dominance model, while co-adaptability was observed in X-p-Cat combination locus of dominance-codominance model and in Po-CA, Po-Cat combination locus of codominance-codominance model. The findings demonstrated that co-adaptability occurred among neutral structural loci and played a key role in maintaining genetic situation, equilibrium or disequilibrium.