A calcium-stimulated serine peptidase from a true-branching cyanobacterium, sp. nov.

Unbranched heterocytous cyanobacteria produce a number of serine peptidases. We have characterized several peptidases in the cell-free extracts of a true-branched N-fixing cyanobacterium, sp. nov.

Phylogenetically distant clade of Nostoc-like taxa with the description of Aliinostoc gen. nov. and Aliinostoc morphoplasticum sp. nov.

Nostoc is a complex and tough genus to differentiate, and its morphological plasticity makes it taxonomically complicated. Its cryptic diversity and almost no distinguishable morphological characteristics make this genus incredibly heterogeneous to evaluate on taxonomic scales. The strain NOS, isolated from a eutrophic water body, is being described as a new genus Aliinostoc with the strain showing motile hormogonia with gas vesicles as an atypical feature, which is currently considered as the diacritical feature of the genus but should be subjected to critical evaluation in the near future.