Gallardo-Navarro Óscar Adrián, Santillán Moisés
Unidad Monterrey, Centro de Investigación y de Estudios Avanzados del IPN, Apodaca, Mexico.
Front Microbiol. 2019 Nov 13;10:2555. doi: 10.3389/fmicb.2019.02555. eCollection 2019.
This work is motivated by previous studies that have analyzed the population ecology of a collection of culturable thermoresistant bacteria, isolated from the Churince lagoon in Cuatro Cienegas, Mexico. In particular, it is aimed at testing a hypothesis from a modeling study, which states that antagonistic and sensitive bacteria co-exist thanks to resistant bacteria that protect sensitive ones by forming physical barriers. We selected three different bacterial strains from the referred collection: one antagonistic, one sensitive, and one resistant, and studied the population dynamics of mixed colonies. Our results show that, although the proposed protective mechanism does not work in this case, the resistant strain confers some kind of protection to sensitive bacteria. Further modeling and experimental results suggest that the presence of resistant bacteria indirectly improves the probability that patches of sensitive bacteria grow in a mixed colony. More precisely, our results suggest that by making antagonistic bacteria produce and secrete an antagonistic substance (with the concomitant metabolic cost and growth rate reduction), resistant bacteria increase the likelihood that sensitive bacteria locally outcompete antagonistic ones.
这项工作的动机来自于之前的研究，这些研究分析了从墨西哥夸特罗谢内加斯的楚林塞泻湖分离出的一批可培养耐热细菌的种群生态学。具体而言，其目的是检验一项建模研究提出的假设，该假设称，拮抗细菌和敏感细菌共存是由于抗性细菌通过形成物理屏障来保护敏感细菌。我们从上述细菌集合中挑选了三种不同的菌株：一种拮抗菌株、一种敏感菌株和一种抗性菌株，并研究了混合菌落的种群动态。我们的结果表明，尽管所提出的保护机制在这种情况下不起作用，但抗性菌株确实为敏感细菌提供了某种保护。进一步的建模和实验结果表明，抗性细菌的存在间接提高了敏感细菌斑块在混合菌落中生长的概率。更确切地说，我们的结果表明，抗性细菌通过使拮抗细菌产生并分泌一种拮抗物质（伴随着代谢成本和生长速率的降低），增加了敏感细菌在局部胜过拮抗细菌的可能性。
