Young and old cultures (up to 66 months) of two Chroococcidiopsis sp. strains isolated from the Negev desert, Israel, were examined by epifluorescence and electron microscopy. In old cultures, cell viability and autofluorescence were lower than in young cultures. An increase was seen with age in the polysaccharide content of the sheaths of nanocytes and nanocyte mother cells, and a decrease of phycobiliproteins was also seen. In the oldest cultures most of the cells were dead and in various stages of degeneration. Single living cells were scattered among the dead ones. No resting cells were formed in the oldest cultures, but many cell groups showed highly electron-dense sheaths and, in the cytoplasm, ribosomes and glycogen. These changes in cell structure may have a role in preventing water loss from the cell.

中文翻译：

---

沙漠蓝细菌 Chroococcidiopsis (Chroococcales) 长期干燥的细胞学

两个 Chroococcidiopsis sp. 的年轻和老文化（最多 66 个月）。通过落射荧光和电子显微镜检查从以色列内盖夫沙漠分离的菌株。在旧培养物中，细胞活力和自发荧光低于年轻培养物中。随着年龄的增长，纳米细胞和纳米细胞母细胞鞘的多糖含量增加，藻胆蛋白也减少。在最古老的培养物中，大多数细胞已经死亡并处于不同的退化阶段。单个活细胞散落在死细胞中。在最古老的培养物中没有形成静息细胞，但许多细胞群显示出高度电子致密的鞘，并且在细胞质中存在核糖体和糖原。细胞结构的这些变化可能在防止细胞失水方面发挥作用。