From June to July 2017, six Seneca Valley virus (SVV) strains were isolated from swine herds exhibiting SVV-associated porcine idiopathic vesicular disease (PIVD) in Guangdong province, China. Complete genomic sequences of these six newly identified strains were genetically and phylogenetically analysed. The results revealed that these six SVV strains were genetically closely related to USA/GBI29/2015 and notably distinct from all previous Chinese strains, indicating the reemergence of new SVV strains in Guangdong province.

Clostridium tyrobutyricum shows probiotic properties and can affect the composition of gut microbiota and regulate the intestinal immune system. Compared with other probiotics, this spore-producing bacterium shows unparalleled advantages in commercial production. In addition to being resistant to extreme living environments for extended periods, its endophytic spores are implicated in inhibiting cancer cell growth. We speculated that C. tyrobutyricum spores can also promote gut health, which mean it can maintain intestinal homeostasis. To date, the beneficial effects of C. tyrobutyricum spores on gut health have not been reported. In this study, a Spo0A-overexpressing C. tyrobutyricum strain was developed to increase spore production, and its probiotic effects on the gut were assessed. Compared with the wild-type, the engineered strain showed significantly increased sporulation rates. Mice administered with the engineered strain exhibited enhanced intestinal villi and the villus height/crypt depth ratio, weight gain and improved Firmicutes/Bacteroidetes ratio to facilitate intestinal homeostasis. This study demonstrated for the first time that enhanced spore production in C. tyrobutyricum can improve intestinal homeostasis, which is advantageous for its commercial application in food and pharmaceutical industry.

Monitoring of cellular cultures oxygen partial pressure (pO2) in liquid phase with a fluorescence quenching based fibre optic oxygen sensor is reported. The sensitivity of the fibre optic oxygen sensor was evaluated in gas phase and calibrated in liquid phase before the monitoring of cell culture pO2 with a luminescence phase detection system. In the experiment of cell culture pO2 monitoring the porcine kidney (PK-15) cells were used as the cell samples and the experimental results showed that the sensor is suitable for monitoring of pO2 in gas and liquid phase. And we found there are different measured pO2 level in liquid phase for different cell densities in cell culture at ambient air environment, which has a PO2 of 21kPa corresponding to an oxygen concentration of 21%. Under the condition of low pO2 in gas phase and high cell density, the cell metabolism could shift pO2 in the liquid phase much lower than that would be from the O2 gas/air equilibrium coefficient, which indicates that the cellular oxygen uptake rate exceeds the oxygen diffusion rate. Therefore there is a need for direct pO2 monitoring in cell culture, particularly in static high density cell culture systems, in which oxygen mass transfer is limited.