• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied and Environmental Microbiology >Periplasmic Cytochrome c3 of Desulfovibrio vulgaris Is Directly Involved in H2-Mediated Metal but Not Sulfate Reduction
【24h】

Periplasmic Cytochrome c3 of Desulfovibrio vulgaris Is Directly Involved in H2-Mediated Metal but Not Sulfate Reduction

机译：脱硫弧菌的周质细胞色素c3直接参与H2介导的金属，但不还原硫酸盐

获取原文
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Kinetic parameters and the role of cytochrome c3 in sulfate, Fe(III), and U(VI) reduction were investigated in Desulfovibrio vulgaris Hildenborough. While sulfate reduction followed Michaelis-Menten kinetics (Km = 220 μM), loss of Fe(III) and U(VI) was first-order at all concentrations tested. Initial reduction rates of all electron acceptors were similar for cells grown with H2 and sulfate, while cultures grown using lactate and sulfate had similar rates of metal loss but lower sulfate reduction activities. The similarities in metal, but not sulfate, reduction with H2 and lactate suggest divergent pathways. Respiration assays and reduced minus oxidized spectra were carried out to determine c-type cytochrome involvement in electron acceptor reduction. c-type cytochrome oxidation was immediate with Fe(III) and U(VI) in the presence of H2, lactate, or pyruvate. Sulfidogenesis occurred with all three electron donors and effectively oxidized the c-type cytochrome in lactate- or pyruvate-reduced, but not H2-reduced cells. Correspondingly, electron acceptor competition assays with lactate or pyruvate as electron donors showed that Fe(III) inhibited U(VI) reduction, and U(VI) inhibited sulfate loss. However, sulfate reduction was slowed but not halted when H2 was the electron donor in the presence of Fe(III) or U(VI). U(VI) loss was still impeded by Fe(III) when H2 was used. Hence, we propose a modified pathway for the reduction of sulfate, Fe(III), and U(VI) which helps explain why these bacteria cannot grow using these metals. We further propose that cytochrome c3 is an electron carrier involved in lactate and pyruvate oxidation and is the reductase for alternate electron acceptors with higher redox potentials than sulfate.
机译：动力学参数和细胞色素c3在硫酸盐，Fe（III）和U（VI）还原中的作用在Desulfovibrio vulgaris Hildenborough中进行了研究。硫酸盐还原遵循Michaelis-Menten动力学（Km = 220μM）时，在所有测试浓度下，Fe（III）和U（VI）的损失都是一阶的。用H2和硫酸盐生长的细胞，所有电子受体的初始还原速率相似，而使用乳酸和硫酸盐生长的培养物具有相似的金属损失速率，但硫酸盐还原活性较低。用H2和乳酸还原金属而不是硫酸盐的相似性表明了不同的途径。进行了呼吸测定和减少的负氧化光谱，以确定c型细胞色素参与电子受体还原。在H2，乳酸或丙酮酸存在下，Fe（III）和U（VI）会立即导致c型细胞色素氧化。所有三个电子供体都发生了硫化作用，并有效地氧化了乳酸或丙酮酸还原的细胞中的c型细胞色素，但没有H2还原的细胞。相应地，以乳酸或丙酮酸为电子供体的电子受体竞争试验表明，Fe（III）抑制U（VI）的还原，而U（VI）抑制硫酸盐的损失。但是，当H2在Fe（III）或U（VI）存在下作为电子供体时，硫酸盐的还原作用减慢但没有停止。使用H2时，Fe（III）仍会阻止U（VI）的损失。因此，我们提出了一条减少硫酸盐，Fe（III）和U（VI）的修饰途径，这有助于解释为什么这些细菌无法使用这些金属生长。我们进一步提出，细胞色素c3是参与乳酸和丙酮酸氧化的电子载体，并且是具有比硫酸盐更高的氧化还原电势的替代电子受体的还原酶。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号