Agricultural and Food Research Council Institute for Grassland and Animal Production, Animal and Grassland Research Station, Hurley, Maidenhead, Berkshire SL6 5LR, and Microbiology Group, Department of Cell and Structural Biology, School of Biological Sciences, University of Manchester, Manchester M13 9PT, United Kingdom.
Appl Environ Microbiol. 1989 Jun;55(6):1363-7. doi: 10.1128/aem.55.6.1363-1367.1989.
The anaerobic fungus Neocallimastix sp. strain R1 was grown for up to 5 days on a medium containing autoclaved Italian ryegrass hay as the carbon source. Culture supernatants and digested cell walls were harvested at 12-h intervals. Supernatants were analyzed for the fermentation products formate and acetate, and residual cell walls were analyzed for dry-matter and neutral-sugar losses. Fungal growth was accompanied by the digestion of plant cell walls and the accumulation of fermentation products in culture media. Dry-matter losses were accounted for by removal of four major neutral sugars (arabinose, galactose, glucose, and xylose) from the plant cell walls. First-order reaction kinetics could be used to describe the loss of each sugar. All cell wall sugars, including arabinose and galactose, which are not fermented by Neocallimastix sp. strain R1 were removed simultaneously. Although the rates of removal of individual sugars were similar, there were significant differences in their extents of removal: the extent of removal of arabinose exceeded that of the other three sugars, and xylose was the least digestible. This study provides the first account of simultaneous (nonpreferential) removal of neutral sugars from plant cell walls by an anaerobic fungus. Although in vitro techniques were used, these results indicate a potentially significant role for the anaerobic fungi as fiber digesters in the rumen.
将灭菌的意大利黑麦草干草作为碳源，用于培养产甲烷丝状真菌 Neocallimastix sp. 菌株 R1，可培养至 5 天。每隔 12 小时收获培养上清液和消化细胞壁。分析上清液中的发酵产物甲酸盐和乙酸盐，分析消化后的细胞壁的干物质和中性糖损失。真菌生长伴随着植物细胞壁的消化和发酵产物在培养基中的积累。干物质损失归因于从植物细胞壁中去除四种主要中性糖（阿拉伯糖、半乳糖、葡萄糖和木糖）。可以使用一级反应动力学来描述每种糖的损失。包括 Neocallimastix sp. 菌株 R1 不发酵的阿拉伯糖和半乳糖在内的所有细胞壁糖都被同时去除。尽管去除各糖的速率相似，但去除的程度存在显著差异：阿拉伯糖的去除程度超过其他三种糖，木糖最难消化。本研究首次描述了一种厌氧真菌同时（非优先）从植物细胞壁中去除中性糖。虽然使用了体外技术，但这些结果表明，厌氧真菌作为反刍动物瘤胃中的纤维消化菌，可能具有重要作用。
