Efficacy of Moxifloxacin against in Zebrafish Model / 生物医学与环境科学（英文）

Objective@#Moxifloxacin (MFX) shows good activity against and can be a possible antibiotic therapy to treat infection; however, other studies have shown a lower or no activity. We aimed to evaluate MFX activity against using zebrafish (ZF) model .@*Methods@#A formulation of labeled with CM-Dil was micro-injected into ZF. Survival curves were determined by recording dead ZF every day. ZF were lysed, and colony-forming units (CFUs) were enumerated. Bacteria dissemination and fluorescence intensity in ZF were analyzed. Inhibition rates of MFX and azithromycin (AZM, positive control) were determined and compared.@*Results@#Significantly increased survival rate was observed with different AZM concentrations. However, increasing MFX concentration did not result in a significant decrease in ZF survival curve. No significant differences in bacterial burdens by CFU loads were observed between AZM and MFX groups at various concentrations. Bacterial fluorescence intensity in ZF was significantly correlated with AZM concentration. However, with increasing MFX concentration, fluorescence intensity decreased slightly when observed under fluorescence microscope. Transferring rates at various concentrations were comparable between the MFX and AZM groups, with no significant difference.@*Conclusion@#MFX showed limited efficacy against using ZF model. Its activity needs to be confirmed.

Emergence of novel canine parvovirus type 2 and its pathogenesis in raccoon dogs.

Three parvoviruses were isolated from the raccoon dogs experiencing severe enteritis, named RDPV-DP1, RDPV-DP2 and RDPV-DP3, respectively. The VP2 genes of the 3 isolates showed 99.9% identity at the nucleotide level, and shared 99.1%-99.5% identity with the reference CPVs. The RDPVs resembled original CPV-2, but with four mutations. The RDPVs displayed S297A of VP2 protein as CPV-2a or CPV-2b prevalent throughout most of the world. Residue N375D was found in the 3 isolates, resembling CPV-2a/2b/2c. And the 3 isolates had a natural mutation of VP2 residue V562L, which is adjacent to residue 564 and 568 and might be involved in host range. Interestingly, VP2 S27T was firstly found in the isolates. Phylogenetic analysis of VP2 genes revealed that the RDPVs were clustered into one small evolutionary branch and shared the identical branch with 7 CPV-2 isolates from raccoon dogs and one CPV-2 isolate from fox, not with CPV vaccine viruses. Phylogenetic analysis of NS1 genes demonstrated that the RDPVs shared the identical branch with the reference CPV-2a/2b/2c. Experimental infection showed that RDPV infection caused a high morbidity in raccoon dogs. It implied that the RDPV was virulent to raccoon dogs and continued to evolve in China.

Serotype and virulence genes of Klebsiella pneumoniae isolated from mink and its pathogenesis in mice and mink.

In the study, 15 K. pneumoniae strains were isolated from the mink experiencing respiratory distress in mideastern Shandong province, China, and the prevalence of K. pneumoniae in the sampled mink was 11.9% (15/126). Fourteen (93.33%) of the 15 K. pneumoniae isolates were identified as serotype K2 and hypermucoviscosity phenotype. The 12 virulence-associated genes of the K. pneumoniae isolates were tested. The prevalence of the wabG gene for the isolates were 100% (15/15), the ureA gene 100% (15/15), the rmpA gene 93.33% (14/15), the aerobactin gene 93.33% (14/15), the uge gene 93.33% (14/15), the IucB gene 80% (12/15) and the ybtA gene 13.33% (2/15). But the other five genes, fim, iroNB, wcaG, alls and kfuBC, gave a negative PCR reaction in the 15 isolates, respectively. The animal experiments using K. pneumoniae-SD-12 and K. pneumoniae-SD-21 demonstrated that the serotype K2 was high virulence for mice and mink. These finding implied there exist potential threat that K. pneumoniae pathogens could transmit to human, especially the fur animal farm workers and residents lived near the fur animal farms. Therefore, the etiology and epidemiological surveillance of K. pneumoniae in mink should be strengthened for people's public health.

Comparison of membrane current of vascular smooth muscle cells in brain artery of spontaneously hypertensive rats and Wistar rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the difference in membrane current of vascular smooth muscle cells (VSMCs) in brain artery (BA) of spontaneously hypertensive rats (SHR) and Wistar rats.</p><p><b>METHODS</b>We compared the properties of spontaneous transient outward K+ currents (STOCs), the density and composition of current of VSMCs in BA of SHR and Wistar rats by whole-cell patch clamp technique.</p><p><b>RESULTS</b>(1) When the command voltage was 0, + 20, + 40 and + 60 mV respectively, the current densities of VSMCs in BA of SHR and Wistar rats were significant different (P < 0.01). (2) The whole-cell current of VSMCs was partly inhibited by 1 mmol/L4-AP (voltage-gated K+ channel blocker) or 1 mmol/L TEA (big conductance Ca(2+)-activated K+ channel blocker) respectively. (3) The frequency and amplitude of STOCs in SHR were faster and bigger than those in Wistar rats. 1 mmol/L TEA almostly inhibited the STOCs, but not by 4-AP.</p><p><b>CONCLUSION</b>These results suggest that the current densities of VSMCs in BA of SHR and Wistar rats are significant different, the outward current of VSMCs in BA of SHR and Wistar rats are composed by Kv and BK(Ca). SHR express more STOCs mediated by BK(Ca), than Wistar rats.</p>

The effects of pH0 on electrophysiological properties of VSMCs in brain artery of spontaneously hypertensive rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the effects of pH0 on the electrophysiological properties of vascular smooth muscle cells (VSMCs) in brain artery of spontaneously hypertension rats (SHR).</p><p><b>METHODS</b>We studied the effects and the ion mechanism of pH0 on whole-cell membrane current of VSMCs in brain artery of 200 - 250 g SHR by whole-cell patch clamp recordings.</p><p><b>RESULTS</b>1. Acidic pH0 could inhibit the outward current of VSMCs of brain artery in SHR in a voltage-dependent manner. It induced a more pronounced inhibition of the outward current from 0 to + 60mV; 2. In the presence of 1 mmol/L TEA, the inhibition of acidic pH0 on the outward current of VSMCs of brain artery was inhibited.</p><p><b>CONCLUSION</b>The changes of outward current of VSMCs of brain artery in SHR induced by pH0 may be connected with BKCa channel.</p>