Arias Dayana, Zepeda Víctor, Nancucheo Ivan, Saldaña Manuel, Galleguillos Pedro A
Laboratory of Molecular Biology and Applied Microbiology, Centro de Investigación en Fisiología y Medicina de Altura (FIMEDALT), Departamento Biomédico, Facultad de Ciencias de la Salud, Universidad de Antofagasta, Antofagasta, Chile.
Scientific and Technological Research Centre for Mining Research, CICITEM, Antofagasta, Chile.
Front Microbiol. 2024 May 24;15:1369244. doi: 10.3389/fmicb.2024.1369244. eCollection 2024.
Iron and sulfur-oxidizing microorganisms play important roles in several natural and industrial processes. () , is an iron-oxidizing microorganism with a remarkable adaptability to thrive in extreme acidic environments, including heap bioleaching processes, acid mine drainage (AMD) and natural acidic water. A strain of (IESL25) was isolated from an industrial bioleaching process in northern Chile. This strain was challenged to grow at increasing concentrations of sulfate in order to assess changes in protein expression profiles, cells shape and to determine potential compatible solute molecules. The results unveiled changes in three proteins: succinyl CoA (SCoA) synthetase, isocitrate dehydrogenase (IDH) and aspartate semialdehyde dehydrogenase (ASD); which were notably overexpressed when the strain grew at elevated concentrations of sulfate. ASD plays a pivotal role in the synthesis of the compatible solute ectoine, which was identified along with hydroxyectoine by using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF). The relationship between IDH, SCoA, and ectoine production could be due to the TCA cycle, in which both enzymes produce metabolites that can be utilized as precursors or intermediates in the biosynthesis of ectoine. In addition, distinct filamentous cellular morphology in IESL25 was observed when growing under sulfate stress conditions. This study highlights a new insight into the possible cellular responses of under the presence of high sulfate levels, commonly found in bioleaching of sulfide minerals or AMD environments.
铁和硫氧化微生物在多个自然和工业过程中发挥着重要作用。嗜酸氧化亚铁硫杆菌是一种铁氧化微生物，对在极端酸性环境中生长具有显著的适应性，这些环境包括堆浸生物浸出过程、酸性矿山排水（AMD）和天然酸性水。从智利北部的一个工业生物浸出过程中分离出了嗜酸氧化亚铁硫杆菌的一个菌株（IESL25）。对该菌株在不断增加的硫酸盐浓度下进行培养，以评估蛋白质表达谱、细胞形态的变化，并确定潜在的相容性溶质分子。结果揭示了三种蛋白质的变化：琥珀酰辅酶A（SCoA）合成酶、异柠檬酸脱氢酶（IDH）和天冬氨酸半醛脱氢酶（ASD）；当该菌株在高浓度硫酸盐下生长时，这些蛋白质显著过表达。ASD在相容性溶质依克多因的合成中起关键作用，通过基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF）鉴定出依克多因以及羟基依克多因。IDH、SCoA与依克多因产生之间的关系可能归因于三羧酸循环，在该循环中这两种酶产生的代谢产物可作为依克多因生物合成的前体或中间体。此外，在硫酸盐胁迫条件下生长时，观察到IESL25具有独特的丝状细胞形态。这项研究突出了对嗜酸氧化亚铁硫杆菌在高硫酸盐水平（常见于硫化矿生物浸出或AMD环境中）存在下可能的细胞反应的新见解。
