Du Yang, Li Hao, Shao Jianchun, Wu Ting, Xu WenLong, Hu Xiaoman, Chen Jiong
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, China.
Laboratory of Biochemistry and Molecular Biology, School of Marine Sciences, Ningbo University, Ningbo, China.
Front Microbiol. 2022 Apr 13;13:878874. doi: 10.3389/fmicb.2022.878874. eCollection 2022.
Surface proteins are a type of proteins expressed on the surface of bacteria that play an important role in cell wall synthesis, maintenance of cell morphology, and signaling with the host. Our previous study showed that the probiotic HC-2 improved the growth performance and immune response of . To further investigate the probiotic mechanism, we determined the automatic aggregation ability of the bacteria and surface hydrophobicity of HC-2 after being treated with 5 M of lithium chloride (LiCl) and observed the morphology and adhesion of the bacteria to HCT116 cells. The results showed that with the removal of the HC-2 surface protein, the auto-aggregation ability and surface hydrophobicity of HC-2 decreased, and the crude mucus layer coated on the bacterial surface gradually dissociated. The adhesion rate of HC-2 to HCT116 cells decreased from 98.1 to 20.9%. Moreover, a total of 201 unique proteins were identified from the mixture of the surface proteins by mass spectrometry (MS). Several proteins are involved in transcription and translation, biosynthetic or metabolic process, cell cycle or division, cell wall synthesis, and emergency response. Meanwhile, a quantitative real-time PCR qPCR_ showed that HC-2 was mainly colonized in the midgut of shrimp, and the colonization numbers were 15 times higher than that in the foregut, while the colonization rate in the hindgut was lower. The adhesion activity measurement showed that the adhesion level of HC-2 to crude intestinal mucus of was higher than that of bovine serum albumin (BSA) and collagen, and the adhesion capacity of the bacterial cells decreased with the extension of LiCl-treatment time. Finally, we identified the elongation factor Tu, Type I glyceraldehyde-3-phosphate dehydrogenase, small heat shock protein, and 30S ribosomal protein from the surface proteins, which may be the adhesion proteins of HC-2 colonization in the shrimp intestine. The above results indicate that surface proteins play an important role in maintaining the cell structure stability and cell adhesion. Surface proteomics analysis contributes to describing potential protein-mediated probiotic-host interactions. The identification of some interacting proteins in this work may be beneficial to further understand the adhesion/colonization mechanism and probiotic properties of HC-2 in the shrimp intestine.
表面蛋白是一类在细菌表面表达的蛋白质，在细胞壁合成、细胞形态维持以及与宿主的信号传导中发挥重要作用。我们之前的研究表明，益生菌HC-2改善了[具体对象]的生长性能和免疫反应。为了进一步研究益生菌机制，我们测定了用5 M氯化锂（LiCl）处理后HC-2细菌的自动聚集能力和表面疏水性，并观察了细菌对HCT116细胞的形态和粘附情况。结果表明，随着HC-2表面蛋白的去除，HC-2的自动聚集能力和表面疏水性降低，细菌表面包裹的粗黏液层逐渐解离。HC-2对HCT116细胞的粘附率从98.1%降至20.9%。此外，通过质谱（MS）从表面蛋白混合物中总共鉴定出201种独特的蛋白质。其中一些蛋白质参与转录和翻译、生物合成或代谢过程、细胞周期或分裂、细胞壁合成以及应急反应。同时，定量实时PCR（qPCR）显示HC-2主要定殖在虾的中肠，定殖数量比前肠高15倍，而后肠的定殖率较低。粘附活性测量表明，HC-2对[具体对象]粗肠黏液的粘附水平高于牛血清白蛋白（BSA）和胶原蛋白，并且随着LiCl处理时间的延长，细菌细胞的粘附能力下降。最后，我们从表面蛋白中鉴定出延伸因子Tu、I型甘油醛-3-磷酸脱氢酶、小热休克蛋白和30S核糖体蛋白，它们可能是HC-2在虾肠道中定殖的粘附蛋白。上述结果表明，表面蛋白在维持细胞结构稳定性和细胞粘附中起重要作用。表面蛋白质组学分析有助于描述潜在的蛋白质介导的益生菌-宿主相互作用。本研究中一些相互作用蛋白的鉴定可能有助于进一步了解HC-2在虾肠道中的粘附/定殖机制和益生菌特性。
