Nostoc muscorum and Spirulina platensis were grown under phosphate deficiency in order to investigate the role of internal phosphate pool and activity of alkaline phosphatase on poly-beta-hydroxybutyrate (PHB) accumulation. PHB accumulation in N. muscorum increased to 22.7% of dry weight (dw) after 4 day of phosphate deficiency, while the internal phosphate pool reduced to the level of 0.02 microM mg dw(-1) at a maximum APase activity of 2.57nM PNP mg dw(-1) h(-1). In contrary, S. platensis depicted maxima of 1.39nM PNP mg dw(-1) h(-1) on day 30 of incubation, which was about 2 fold lower than the observed value of N. muscorum. PHB content in S. platensis remained low even after prolonged phosphate starvation, and a rise only up to 3.5% of dw was recorded on day 60 of phosphate deficiency. Supplementation of NADPH exogenously to S. platensis cultures grown under phosphate deficiency favoured PHB accumulation in 10, 20 and 30 days old cultures, but not in the cultures grown under phosphate deficiency for 60 days. The possible role of phosphate limitation on PHB accumulation is discussed.

中文翻译：

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磷酸盐限制下发菜和螺旋藻中聚-β-羟基丁酸的积累

为了研究内部磷酸盐库和碱性磷酸酶活性对聚 β-羟基丁酸 (PHB) 积累的作用，在磷缺乏条件下培养发菜和螺旋藻。磷缺乏 4 天后，小猪笼草中的 PHB 积累增加到干重 (dw) 的 22.7%，而内部磷酸盐池减少到 0.02 microM mg dw(-1) 的水平，最大 APase 活性为 2.57nM PNP毫克 dw(-1) h(-1)。相反，S. platensis 在孵化的第 30 天描绘了 1.39nM PNP mg dw(-1) h(-1) 的最大值，比观察到的 N. muscorum 值低约 2 倍。即使经过长时间的磷酸盐饥饿，S. platensis 中的 PHB 含量仍然很低，并且在磷酸盐缺乏的第 60 天记录到的 dw 仅增加了 3.5%。外源性补充 NADPH 到 S. 在缺磷条件下生长的 platensis 培养物在 10、20 和 30 天龄的培养物中有利于 PHB 的积累，但在缺磷条件下生长 60 天的培养物中则不然。讨论了磷酸盐限制对 PHB 积累的可能作用。