FORMALDEHYDE METABOLISM IN PURPLE NON SULPHUR BACTERIUM RHODOBACTER SPHAEROIDES

紫色非硫球红细菌中的甲醛代谢

• 批准号: 6309148
• 负责人: TIMOTHY J DONOHUE
• 金额: $ 0.75万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-15 至 2005-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6309148
• 关键词: bacteria; biomedical resource; hormones; nuclear magnetic resonance spectroscopy; proteins

We are investigating the pathway of formaldehyde assimilation in the purple non-sulphur bacterium Rhodobacter sphaeroides. Purple non-sulphur bacteria are well known for their metabolic diversity, using a wide variety of substrates for carbon and energy needs. The metabolism of some of these substrates, specifically methylated compounds, generates formaldehyde that must be further metabolized or would prove toxic to the cells. Our data suggest that formaldehyde's fate in R. sphaerodies is dependent on whether cells are grown in the presence or absence of oxygen. Under anaerobic (photosynthetic) growth conditions, R. sphaeroides is able to grow using methanol as a sole carbon source. Since formaldehyde is the immediate product of methanol oxidation, it must provide all the carbon skeletons for R. sphaeroides under photosynthetic growth conditions. Of the pathways that have previously been described for formaldehyde assimilation in microbes, enzyme assays in crude extracts suggest that R. sphaerodies may use either the Serine-Isocitrate cycle or the Calvin cycle for photosynthetic methylotrophic growth. Under aerobic growth conditions, similar enzyme assays suggest that formaldehyde is oxidized to carbon dioxide and released to the atmosphere thus detoxifiying formaldehyde form the cells. By using 13C-labeled substrates in enzyme assays, we hope to confirm the path(s) of formaldehyde oxidation products in these cells. By showing that the predicted products are formed when specific formaldehyde pathway intermediates are added to R. sphaeroides extracts, we will provide direct evidence to support our tentative pathway for formaldehyde oxidation in the presence and absence of oxygen.

我们正在研究甲醛同化的途径 紫色非硫酸细菌杜鹃花杆菌。 紫色的 非硫细菌以其代谢多样性而闻名 使用各种碳和能量需求的基材。 这 其中一些底物的代谢，特别是甲基化的 化合物，生成必须进一步代谢或 证明对细胞有毒。 我们的数据表明甲醛 Sphaerodies中的命运取决于细胞是否在 存在或不存在氧气。 在厌氧（光合作用）下 生长条件，R。sphaeroides能够使用甲醇作为一种 唯一的碳源。 由于甲醛是 甲醇氧化，必须为R提供所有碳骨架。 光合生长条件下的Sphaeroides。 路径 以前已经描述了甲醛同化 微生物，粗提取物中的酶测定表明R. sphaerodies 可以使用丝氨酸 - 异构酸周期或加尔文周期 光合甲基营养的生长。 在有氧生长下 条件，类似的酶测定表明甲醛是 氧化为二氧化碳并释放到大气中 排毒甲醛形成细胞。 通过使用13C标记 酶测定中的底物，我们希望确认 这些细胞中的甲醛氧化产物。 通过表明 当特定甲醛途径时形成预测的产品 中间体被添加到R. sphaeroides提取物中，我们将提供 直接证据支持我们甲醛的暂定途径 在存在和不存在氧气的情况下氧化。