McCarthy C
Infect Immun. 1976 Nov;14(5):1241-52. doi: 10.1128/iai.14.5.1241-1252.1976.
Mycobacterium avium exhibits a life cycle wherein small cells elongate to form filaments. The life cycle is unique in that elongated cells will undergo rapid division by fragmentation only if fatty acid is present. The utilization of [14C]palmitic acid and [3H]oleic acid by M. avium during the life cycle was assessed. Four glycolipids, identifiable by elution patterns from hydroxylapatite columns, were associated with postfission cells and contained isotope from the precursor fatty acid. The incorporation of 3H from oleic acid into the cellular glycolipids was maximal during cell division, but as much as 73% of the radioactivity was lost to the lipids from cells in the postfission status. Three of the glycolipids were sulfatides into which 36S was incorporated by M. avium. The [35]sulfatides were synthesized by cells undergoing fragmentation and were recovered from the medium at the termination of cell fission. These results demonstrated that the isotope was not lost to the cells because of turnover, but rather that the labeled compounds were released, intact, from the cells after fission. Because of the facile release of the sulfolipids, it was suggested that they were part of the cell envelope of M. avium cells during the division process.
鸟分枝杆菌呈现出一个生命周期，其中小细胞伸长形成细丝。该生命周期的独特之处在于，只有在脂肪酸存在的情况下，伸长的细胞才会通过碎片化进行快速分裂。评估了鸟分枝杆菌在生命周期中对[14C]棕榈酸和[3H]油酸的利用情况。通过羟基磷灰石柱的洗脱模式可鉴定出四种糖脂，它们与分裂后的细胞相关，并含有来自前体脂肪酸的同位素。油酸中的3H掺入细胞糖脂的量在细胞分裂期间最大，但高达73%的放射性在分裂后状态的细胞中损失到脂质中。其中三种糖脂是硫脂，鸟分枝杆菌将36S掺入其中。[35]硫脂由正在进行碎片化的细胞合成，并在细胞分裂结束时从培养基中回收。这些结果表明，同位素不是因为周转而从细胞中丢失，而是标记化合物在分裂后完整地从细胞中释放出来。由于硫脂易于释放，有人认为它们在分裂过程中是鸟分枝杆菌细胞膜的一部分。
