Preliminary study on the role of novel LysR family gene kp05372 in Klebsiella pneumoniae of forest musk deer / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

LysR-type transcriptional regulators are involved in the regulation of numerous cellular metabolic processes in Klebsiella pneumoniae, leading to severe infection. Earlier, we found a novel LysR family gene, named kp05372, in a strain of K. pneumoniae (designated GPKP) isolated from forest musk deer. To study the function of this gene in relation to the biological characteristics of GPKP, we used the suicide plasmid and conjugative transfer methods to construct deletion mutant strain GPKP-Δkp05372; moreover, we also constructed the GPKP-Δkp05372+ complemented strain. The role of this gene was determined by comparing the following characteristics of three strains: growth curves, biofilm formation, drug resistance, stress resistance, median lethal dose (LD50), organ colonization ability, and the histopathology of GPKP. Real-time polymerase chain reaction (RT-PCR) was used to test the expression level of seven genes upstream of kp05372. There was no significant difference in the growth rates when comparing the three bacterial strains, and no significant difference was recorded at different osmotic pressures, temperatures, salt contents, or hydrogen peroxide concentrations. The GPKP-Δkp05372 mutant formed a weak biofilm, and the other two strains formed medium biofilm. The drug resistance of the GPKP-Δkp05372 mutant toward cephalothin, cotrimoxazole, and polymyxin B was changed. The acid tolerance of the deletion strain was strongerthan that of the othertwo strains. The LD50 values of the wild-type and complemented strains were 174-fold and 77-fold higher than that of the GPKP-Δkp05372 mutant, respectively. The colonization ability of the GPKP-Δkp05372 mutant in the heart, liver, spleen, kidney, and intestine was the weakest. The three strains caused different histopathological changes in the liver and lungs. In the GPKP-Δkp05372 mutant, the relative expression levels of kp05374 and kp05379 were increased to 1.32-fold and 1.42-fold, respectively, while the level of kp05378 was decreased by 42%. Overall, the deletion of kp05372 gene leads to changes in the following: drug resistance and acid tolerance; decreases in virulence, biofilm formation, and colonization ability of GPKP; and regulation of the upstream region of adjacent genes.

Preliminary study on the role of novel LysR family gene kp05372 in Klebsiella pneumoniae of forest musk deer / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

LysR-type transcriptional regulators are involved in the regulation of numerous cellular metabolic processes in Klebsiella pneumoniae, leading to severe infection. Earlier, we found a novel LysR family gene, named kp05372, in a strain of K. pneumoniae (designated GPKP) isolated from forest musk deer. To study the function of this gene in relation to the biological characteristics of GPKP, we used the suicide plasmid and conjugative transfer methods to construct deletion mutant strain GPKP-Δkp05372; moreover, we also constructed the GPKP-Δkp05372+ complemented strain. The role of this gene was determined by comparing the following characteristics of three strains: growth curves, biofilm formation, drug resistance, stress resistance, median lethal dose (LD50), organ colonization ability, and the histopathology of GPKP. Real-time polymerase chain reaction (RT-PCR) was used to test the expression level of seven genes upstream of kp05372. There was no significant difference in the growth rates when comparing the three bacterial strains, and no significant difference was recorded at different osmotic pressures, temperatures, salt contents, or hydrogen peroxide concentrations. The GPKP-Δkp05372 mutant formed a weak biofilm, and the other two strains formed medium biofilm. The drug resistance of the GPKP-Δkp05372 mutant toward cephalothin, cotrimoxazole, and polymyxin B was changed. The acid tolerance of the deletion strain was stronger than that of the other two strains. The LD50 values of the wild-type and complemented strains were 174-fold and 77-fold higher than that of the GPKP-Δkp05372 mutant, respectively. The colonization ability of the GPKP-Δkp05372 mutant in the heart, liver, spleen, kidney, and intestine was the weakest. The three strains caused different histopathological changes in the liver and lungs. In the GPKP-Δkp05372 mutant, the relative expression levels of kp05374 and kp05379 were increased to 1.32-fold and 1.42-fold, respectively, while the level of kp05378 was decreased by 42%. Overall, the deletion of kp05372 gene leads to changes in the following: drug resistance and acid tolerance; decreases in virulence, biofilm formation, and colonization ability of GPKP; and regulation of the upstream region of adjacent genes.

Microbial diversity of musk across its maturation process in forest musk deer / 中国中药杂志

Musk,with unique and intense perfume,was a kind of deep brown precious medicinal material in traditional Chinese medicine. However,the immature musk in musk pot was white and stench. Given the fact that bacterial diversity generated odorous metabolites in animal hosts,in this study,musk samples at three different mature stages,including MJ( the end of June),MA( the end of August) and MO( the end of October) were harvested from three male forest musk deer,and then next-generation sequencing was used to intensively survey the bacterial communities in musk harvested at different mature stages. RESULTS: indicated that the average OTUs per sample at the end of June,August and October were 47 116. 00 ± 1 567. 24( SE),52 009. 00 ± 8 958. 75( SE) and50 004. 67±4 135. 57( SE),respectively. Feature of the musk 16 S rRNA gene showed a total of 418 genera belonging to 52 phyla were observed in all samples. The main microbiota was bacteria,which accounted for 98. 82%,99. 95% and 99. 58% in MJ,MA and MO,respectively. At phylum level,Firmicutes was the most abundant bacterial of MA( 32. 75%) and MO( 39. 19%). While,the major bacterial in MJ was Proteobacteria( 49. 14%). PICRUSt analysis revealed the functions of bacterial in MJ were mainly involved in secretion,while bacterial functions of MA and MO were mainly involved in amino acid or other substance metabolism,which was in accord with the musk secretion physiological process of forest musk deer. This is the first study involved in the bacterial diversity in musk of forest musk deer across the maturation process,while may provide a new insight into the musk generation mechanism.