Jung Hae-In, Kim Yun-Jung, Lee Yun-Jung, Lee Hee-Soo, Lee Jung-Kee, Kim Soo-Ki
Department of Animal Science and Technology, Konkuk University, Seoul, 05029, Republic of Korea.
National Veterinary Research and Quarantine Service, Anyang, 14033, Republic of Korea.
J Microbiol. 2017 Oct;55(10):800-808. doi: 10.1007/s12275-017-7374-7. Epub 2017 Sep 28.
Burkholderia sp. is a gram-negative bacterium that commonly exists in the environment, and can cause diseases in plants, animals, and humans. Here, a transposon mutant library of a Burkholderia lata isolate from a pig with swine respiratory disease in Korea was screened for strains showing attenuated virulence in Caenorhabditis elegans. One such mutant was obtained, and the Tn5 insertion junction was mapped to rpfR, a gene encoding a cyclic di-GMP phosphodiesterase that functions as a receptor. Mutation of rpfR caused a reduction in growth on CPG agar and swimming motility as well as a rough colony morphology on Congo red agar. TLC analysis showed reduced AHL secretion, which was in agreement with the results from plate-based and bioluminescence assays. The mutant strain produced significantly more biofilm detected by crystal violet staining than the parent strain. SEM of the mutant strain clearly showed that the overproduced biofilm contained a filamentous structure. These results suggest that the cyclic di-GMP phosphodiesterase RpfR plays an important role in quorum sensing modulation of the bacterial virulence and biofilm formation.
伯克霍尔德氏菌属是一种革兰氏阴性细菌，通常存在于环境中，可导致植物、动物和人类患病。在此，对从韩国一头患有猪呼吸道疾病的猪身上分离出的一株迟缓伯克霍尔德菌构建的转座子突变体文库进行筛选，以寻找在秀丽隐杆线虫中显示毒力减弱的菌株。获得了一个这样的突变体，并将Tn5插入位点定位到rpfR，该基因编码一种作为受体起作用的环二鸟苷酸磷酸二酯酶。rpfR突变导致在CPG琼脂上生长减少、游动能力下降以及在刚果红琼脂上菌落形态粗糙。薄层色谱分析显示AHL分泌减少，这与基于平板和生物发光测定的结果一致。通过结晶紫染色检测发现，突变菌株产生的生物膜明显多于亲本菌株。突变菌株的扫描电子显微镜观察清楚地表明，过量产生的生物膜含有丝状结构。这些结果表明，环二鸟苷酸磷酸二酯酶RpfR在细菌毒力的群体感应调节和生物膜形成中起重要作用。
