ABSTRACT Two cyanobacterial strains developed morphology characteristic of Nostochopsis, i.e. with many heterocysts in side branches when grown in low phosphate medium. When grown in high phosphate medium both strains developed morphology characteristic of Fischerella muscicola. The converse did not occur with two culture strains classified as Fischerella in that neither developed Nostochopsis morphology when grown in low phosphate. However, there was a slight increase in the percentage of heterocysts that were closely attached to main trichome axes rather than to a cell-forming part of the axis. However, all analysed strains had similar increases in surface phosphomonoesterase activities under low phosphate. Because some literature on Nostochopsis in the field indicates that it can be found only at one time of year, the possibility is discussed that it is recognised only when phosphate is limited. It seems likely that contradictory results in past molecular literature resulted from the same strain being compared in different studies, one using low and the other using high phosphate medium. Our molecular analysis supports morphological differences between the studied strains, and taxonomic assignments are discussed on the basis of previous phylogenetic analyses. Abbreviations: PMEase; phosphomonoesterase activity; pNPP, para-nitrophenyl phosphate

中文翻译：

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磷酸盐对 Nostochopsis 样形态（蓝藻）的影响

摘要 两种蓝藻菌株发展出 Nostochopsis 的形态特征，即在低磷酸盐培养基中生长时在侧枝中有许多杂囊。当在高磷酸盐培养基中生长时，两种菌株都形成了 Fischerella muscicola 的形态特征。两种被归类为 Fischerella 的培养菌株没有发生相反的情况，因为当在低磷酸盐中生长时，它们都没有形成 Nostochopsis 形态。然而，与主要毛状体轴而不是轴的细胞形成部分紧密相连的异囊的百分比略有增加。然而，所有分析的菌株在低磷酸盐下的表面磷酸单酯酶活性都有相似的增加。因为该领域一些关于 Nostochopsis 的文献表明它只能在一年中的一个时间被发现，讨论了只有在磷酸盐有限的情况下才能认识到的可能性。过去分子文献中的矛盾结果似乎可能是由于在不同研究中比较同一菌株，一个使用低磷酸盐培养基，另一个使用高磷酸盐培养基。我们的分子分析支持所研究菌株之间的形态差异，并且在先前的系统发育分析的基础上讨论了分类分配。缩写：PMEase；磷酸单酯酶活性；pNPP，对硝基苯基磷酸酯 我们的分子分析支持所研究菌株之间的形态差异，并且在先前的系统发育分析的基础上讨论了分类分配。缩写：PMEase；磷酸单酯酶活性；pNPP，对硝基苯基磷酸酯 我们的分子分析支持所研究菌株之间的形态差异，并且在先前的系统发育分析的基础上讨论了分类分配。缩写：PMEase；磷酸单酯酶活性；pNPP，对硝基苯基磷酸酯