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Abstract：
Studies on Bdellovibrio and like organisms (BALOs), obligate predatory bacteria, have highlighted the possibility of regulating bacteria and biofilms; however, yak-derived BALOs are yet to be reported. We aimed to characterize the BALOs isolated and identified from yak (Bos grunniens) feces and examine application potential. BALOs were isolated from healthy yak fecal samples, with Escherichia coli (ATCC 25922) as prey using the double-layer agar method, identified by transmission electron microscopy (TEM), and the specific 16S rDNA sequencing analysis. Sequencing of the 16S rDNA gene indicated that this isolate was 91% similar to the Bdellovibrio sp. NC01 reference strain and was named YBD-1. Proportion of YBD-1 lysed bacteria is 12/13. The YBD-1 showed best growth at 25-40°C, 0-0.25% (w/v) NaCl, and pH 6.5-7.5. YBD-1 significantly reduced the planktonic cells and biofilms of E.coli in co-culture compared to the E.coli group. Additionally, SEM analysis indicated that YBD-1 significantly reduced biofilm formation in E. coli. Furthermore, quantitative Real Time-polymerase chain reaction (qRT-PCR) showed that the expression of the virulence genes fim and iroN and the genes pgaABC involved in biofilm formation went down significantly. We concluded that YBD-1 may have the potential to control bacterial growth and biofilm-associated bacterial illnesses.
摘要：
对Bdellovibrio和类似生物（BALOs）的研究，专性掠食性细菌，强调了调节细菌和生物膜的可能性；然而，牦牛衍生的BALOs尚未报告。我们旨在表征从牦牛（Bosgrunniens）粪便中分离和鉴定的BALOs，并研究其应用潜力。从健康牦牛粪便样本中分离出BALOs，以大肠杆菌（ATCC25922）为猎物，采用双层琼脂法，通过透射电子显微镜（TEM）鉴定，和特定的16SrDNA测序分析。16SrDNA基因的测序表明，该分离株与Bdellovibriosp。NC01参考菌株并命名为YBD-1。YBD-1裂解细菌的比例为12/13。YBD-1在25-40°C时表现出最佳生长，0-0.25%(w/v)NaCl,和pH6.5-7.5。与大肠杆菌组相比,YBD-1显著减少共培养中大肠杆菌的浮游细胞和生物膜。此外,SEM分析表明YBD-1显著减少大肠杆菌中生物膜的形成。此外，定量实时聚合酶链反应（qRT-PCR）显示，毒力基因fim和iroN以及参与生物膜形成的基因pgaABC的表达显着下降。我们得出结论，YBD-1可能具有控制细菌生长和生物膜相关细菌疾病的潜力。
