Rossi Franca, Amadoro Carmela, Pallotta Maria Luigia, Colavita Giampaolo
Diagnostica Specialistica, Sezione di Campobasso, Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise "G. Caporale", Via Garibaldi 155, 86100 Campobasso, Italy.
Medicine and Health Science Department "V. Tiberio", University of Molise, Via de Santis, 86100 Campobasso, Italy.
Microorganisms. 2022 May 13;10(5):1023. doi: 10.3390/microorganisms10051023.
This study aims to explore the intra-species distribution of genetic characteristics that favor the persistence in the gastrointestinal tract (GIT) and host interaction of bacteria belonging to species of the genus. These bacterial species comprise commercial probiotics with the widest use among consumers and strains naturally occurring in GIT and in fermented food. Since little is known about the distribution of genetic traits for adhesion capacity, polysaccharide production, biofilm formation, and utilization of substrates critically important for survival in GIT, which influence probiotic characteristics, a list of genetic determinants possibly involved in such functions was created by a search for specific genes involved in the above aspects in the genome of the extensively characterized probiotic GG. Eighty-two gene loci were retrieved and their presence and variability in other spp. genomes were assessed by alignment with the publicly available fully annotated genome sequences of , , , and . Forty-nine of these genes were found to be absent in some strains or species. The remaining genes were conserved and covered almost all the functions considered, indicating that all strains of the genus may exert some probiotic effects. Among the variable loci, a taurine utilization operon and a α-L-fucosidase were examined for the presence/absence in 26 strains isolated from infant feces by PCR-based tests. Results were variable among the isolates, though their common origin indicated the capacity to survive in the intestinal niche. This study indicated that the capacity to exert probiotic actions of spp. depends on a conserved set of genes but variable genetic factors, whose role is only in part elucidated, are more numerous and can explain the enhanced probiotic characteristics for some strains. The selection of the most promising probiotic candidates to be used in food is feasible by analyzing the presence/absence of a set of variable traits.
本研究旨在探索有利于在胃肠道（GIT）中持续存在以及与该属细菌宿主相互作用的遗传特征的种内分布。这些细菌种类包括在消费者中使用最广泛的商业益生菌，以及自然存在于胃肠道和发酵食品中的菌株。由于对于对在胃肠道中生存至关重要的黏附能力、多糖产生、生物膜形成和底物利用等遗传特征的分布了解甚少，而这些特征会影响益生菌特性，因此通过在广泛表征的益生菌GG基因组中搜索涉及上述方面的特定基因，创建了一份可能参与此类功能的遗传决定因素清单。检索到82个基因座，并通过与公开可用的、、和的完全注释基因组序列进行比对，评估它们在其他 spp. 基因组中的存在和变异性。发现其中49个基因在某些菌株或物种中不存在。其余基因是保守的，几乎涵盖了所有考虑的功能，表明该属的所有菌株可能都发挥一些益生菌作用。在可变基因座中，通过基于PCR的测试检查了26株从婴儿粪便中分离的菌株中牛磺酸利用操纵子和α-L-岩藻糖苷酶的存在/缺失情况。尽管分离株的共同来源表明它们有在肠道生态位中生存的能力，但结果在分离株之间存在差异。本研究表明， spp. 发挥益生菌作用的能力取决于一组保守基因，但可变遗传因素数量更多，其作用仅部分得到阐明，并且可以解释某些菌株增强的益生菌特性。通过分析一组可变特征的存在/缺失情况，选择最有前途的益生菌候选物用于食品是可行的。
