Genetic characterization of bovine viral diarrhea virus strains in Beijing, China and innate immune responses of peripheral blood mononuclear cells in persistently infected dairy cattle

To acquire epidemiological data on the bovine viral diarrhea virus (BVDV) and identify cattle persistently infected (PI) with this virus, 4,327 samples from Holstein dairy cows were screened over a four-year period in Beijing, China. Eighteen BVD viruses were isolated, 12 from PI cattle. Based on genetic analysis of their 5'-untranslated region (5'-UTR), the 18 isolates were assigned to subgenotype BVDV-1m, 1a, 1d, 1q, and 1b. To investigate the innate immune responses in the peripheral-blood mononuclear cells of PI cattle, the expression of Toll-like receptors (TLRs), RIG-I-like receptors, interferon-alpha (IFN-alpha), IFN-beta, myxovirus (influenza virus) resistance 1 (MX1), and interferon stimulatory gene 15 (ISG15) was assessed by qPCR. When compared with healthy cattle, the expression of TLR-7, IFN-alpha, and IFN-beta mRNA was downregulated, but the expression of MX1 and ISG-15 mRNA was upregulated in PI cattle. Immunoblotting analysis revealed that the expression of interferon regulatory factor 3 (IRF-3) and IRF-7 was lower in PI cattle than in healthy cattle. Thus, BVDV-1m and 1a are the predominant subgenotypes in the Beijing region, and the strains are highly divergent. Our findings also suggest that the TLR-7/IRF-7 signaling pathway plays a role in evasion of host restriction by BVDV.

Effects of chronic multiple stress on learning and memory and the expression and phosphorylation of cerebral ERK of rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the effect of chronic multiple stress on learning and memory, and the expression and activation of cerebral extracellular signal-regulated protein kinase (ERK) 1/2 of rats in vivo.</p><p><b>METHODS</b>Ninety male SD rats were divided randomly into control group and stress group. Rats in stress group were stressed everyday by one of the seven stressors including cold exposure, foot shock, white noise, restraint, tail hung up, sleep deprivation, and level shake, and then the ability of learning and memory was determined by Morris water maze test. Serum corticosterone (CORT) level was determined by radioimmunoassay kit. Western blot was performed to determine the expression and phosphorylation of ERK in hippocampus and prefrontal cortex of the brain.</p><p><b>RESULTS</b>The escape latencies of stressed rats were substantially longer than those of the controls in the water maze test (P < 0.01) except a transient recovery at the end of the third week after the stress. The stress also resulted in significantly higher serum CORT level and decreased P-ERK level in hippocampus and prefrontal cortex (PFC) (P < 0.01). Similarly, transient elevation of both CORT and P-ERK levels were observed at the end of the third week.</p><p><b>CONCLUSION</b>Chronic multiple stress can lead to impaired learning and memory by decreasing the phosphorylation of ERK in the hippocampus and PFC. The partial recovery of learning and memory, CORT and P-ERK levels at the end of the third week may due to the adaptation of the rats to stressors.</p>