Hafniaparalgivi,革兰氏阴性食源性病原体,在各种水生动物和海鲜中普遍存在,可以形成生物膜作为主要毒力因子,有助于其发病机理。然而,嗜血杆菌的生物膜形成机制及其对食物腐败的影响尚未得到充分表征。这里我们展示了生物膜的形成,受bcsB介导的c-di-GMP调控,可以增加嗜血杆菌的腐败能力。我们发现外源添加GTP可以增强c-di-GMP的合成,进一步促进了生物膜的形成。基因dgcC,嗜血杆菌中11个编码含有GGDEF结构域蛋白的基因之一,以GTP为底物显著上调。dgcC的上调有助于c-di-GMP的显著增加和生物膜的形成。此外,dgcC的过表达诱导bcsB的上调,报道的效应蛋白编码基因,进一步证明bcsB的过表达可以促进细菌纤维素的合成和生物膜的形成。通过感官评价评估了c-di-GMP诱导的生物膜形成对黄河鲤鱼(Cyprinuscarpio)腐败的影响,总的可行计数,和总挥发性碱性氮,结果表明,生物膜的形成可以显着增加H.paralgypi在C.carpio上的腐败能力。我们的发现提供了c-di-GMP对bcsB表达的调节,这可能有助于H.parsulphi的生物膜形成和腐败能力,这有利于了解哈夫尼菌的发病机制及其在食物腐败中的作用。
Hafnia paralvei, a Gram-negative foodborne pathogen, is found ubiquitously in various aquatic animals and seafoods, which can form biofilm as a dominant virulence factor that contributes to its pathogenesis. However, the biofilm formation mechanism of H. paralvei and its effect on food spoilage has not been fully characterized. Here we show that biofilm formation, is regulated by c-di-GMP which mediated by bcsB, can increase the spoilage ability of H. paralvei. We found that GTP was added exogenously to enhance the synthesis of c-di-GMP, which further promoted biofilm formation. The gene dgcC, one of 11 genes encoding GGDEF domain-containing proteins in H. paralvei, was significantly upregulated with GTP as substrate. The upregulation of dgcC contributes to a significant increase of c-di-GMP and the formation of biofilm. In addition, the overexpression of dgcC induced upregulation of bcsB, a reported effector protein encoding gene, which was further demonstrated that overexpression of bcsB can encourage the synthesis of bacterial cellulose and biofilm formation. The effect of biofilm formation induced by c-di-GMP on spoilage of Yellow River carp (Cyprinus carpio) was evaluated by sensory evaluation, the total viable count, and the total volatile basic nitrogen, which showed that biofilm formation can significantly increase the spoilage ability of H. paralvei on C. carpio. Our findings provide the regulation of c-di-GMP on expression of bcsB, that can contribute to biofilm formation and spoilage ability of H. paralvei, which is favor to understanding the pathogenesis of Hafnia paralvei and its role in food spoilage.