Controls on the Concentration of Bacterial Cell Surface Sulfhydryl Sites: Effects of Inorganic Nutrients
Controls on the Concentration of Bacterial Cell Surface Sulfhydryl Sites: Effects of Inorganic Nutrients
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DOI：
10.1080/01490451.2022.2027050
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发表时间：
2022-02
影响因子：
2.3
通讯作者：
Qiang Yu;J. Fein
中科院分区：
文献类型：
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作者：
Qiang Yu;J. Fein
了解细菌表面巯基位点浓度的控制对于模拟细菌细胞对环境中亲铜金属的命运和运输的影响至关重要。在这项研究中，我们研究了在生长培养基中改变MgSO4、NaCl和NaNO3的浓度对革兰氏阳性细菌枯草芽孢杆菌细胞表面巯基位点浓度的影响，采用电位滴定法测量。我们的研究结果表明，在低MgSO4浓度下，M9最小培养基中的MgSO4浓度对细菌表面巯基位点浓度有很强的影响，但随着MgSO4浓度的增加，这种影响趋于平稳，这表明细菌需要最少量的硫源来产生细胞表面巯基位点。虽然在含有0.1 mM MgSO4的M9最小培养基中生长的生物质样品的巯基位点浓度低于检测限，但增加培养基中NaCl或NaNO3的浓度会产生可测量到细胞表面巯基位点浓度的生物质样品。相比之下，在M9培养基中加入氯化钠并没有增加细胞表面巯基位点的浓度。NaCl和NaNO3效应的产生可能是因为在M9最小培养基中增加NaCl或NaNO3浓度可以促进细菌产生EPS，并且枯草芽孢杆菌的表面巯基位点主要位于其EPS分子上。本研究结果表明，细菌营养成分和水化学组成是细菌表面巯基位点丰度的关键控制因素。
Abstract Understanding the controls on bacterial surface sulfhydryl site concentrations is crucial for modeling the effects of bacterial cells on the fate and transport of chalcophile metals in the environment. In this study, we investigate the effects of changing the concentrations of MgSO4, NaCl and NaNO3 in a growth medium on the concentration of cell surface sulfhydryl sites on the Gram-positive bacterial species Bacillus subtilis, as measured using a potentiometric titration approach. Our results show that the concentration of MgSO4 in a M9 minimal medium exerts a strong influence on bacterial surface sulfhydryl site concentrations under low MgSO4 concentrations but that this effect plateaus with increasing MgSO4 concentrations, indicating that a minimum amount of a sulfur source is required for bacteria to produce cell surface sulfhydryl sites. Although the sulfhydryl site concentration was below the detection limit on biomass samples that were grown in a M9 minimal medium containing 0.1 mM MgSO4, increasing the concentration of either NaCl or NaNO3 in the medium yielded biomass samples with measurable sulfhydryl site concentrations on the cell surface. In contrast, adding NaClO4 to the M9 medium did not increase cell surface sulfhydryl site concentrations. The NaCl and NaNO3 effects likely arise because increasing the concentration of NaCl or NaNO3 in a M9 minimal medium can promote the production of EPS by bacteria, and because the surface sulfhydryl sites of B. subtilis are located mostly on its EPS molecules. The results of this study suggest that bacterial nutrients and water chemistry composition are key controls on the abundance of bacterial surface sulfhydryl sites.