A novel coccoid-shaped cyanobacterium, Myxosarcina sp. KIOST-1 isolated from Mangrove Forest in Chuuk State, Federated States of Micronesia

Abstract

A cyanobacterium was isolated from root sediment of mangrove forest in Chuuk State, Federated States of Micronesia (FSM), and then the isolate was cultured in f/2 medium. From the culture medium, an entangled, dark-brown, coccoid cyanobacterium was observed and identified by its morphological and molecular characteristics. Microscopic analysis revealed that size of yellow-brown or grayish periphytic cell ranged 3&#8211 5 &micro m in diameter, and the colonies were densely packed 4&#8211 64 non-polarized blastoparenchymatous cells, arranged more or less regularly. Ultrastructural analysis showed progress of cell division in the inner sheath, while some motile nanocytes of 0.5&#8211 0.8 &micro m in diameter was observed during its reproduction under light microscopic analysis. To determine the taxonomical position of the cyanobaterium, 16S rRNA gene was sequenced and phylogenetic analysis was constructed. Accordingly, the result indicated that the isolated cyanobacterium was most similar to the genus Myxosarcina, however, it not clearly separated from the genera Chroococcidiopsis and Dermocarpella. Therefore, the reproduction type and motility of progeny cells were considered as key characteristics in the final identification, and the isolated cyanobacterium was finally classified in the genus Myxosarcina and designated Myxosarcina sp. KIOST-1. These findings will help to advance our understanding of the cyanobacteririum was observed and identified by its morphological and molecular characteristics. Microscopic analysis revealed that size of yellow-brown or grayish periphytic cell ranged 3&#8211 5 &micro m in diameter, and the colonies were densely packed 4&#8211 64 non-polarized blastoparenchymatous cells, arranged more or less regularly. Ultrastructural analysis showed progress of cell division in the inner sheath, while some motile nanocytes of 0.5&#8211 0.8 &micro m in diameter was observed during its reproduction under light microscopic analysis. To determine the taxonomical position of the cyanobaterium, 16S rRNA gene was sequenced and phylogenetic analysis was constructed. Accordingly, the result indicated that the isolated cyanobacterium was most similar to the genus Myxosarcina, however, it not clearly separated from the genera Chroococcidiopsis and Dermocarpella. Therefore, the reproduction type and motility of progeny cells were considered as key characteristics in the final identification, and the isolated cyanobacterium was finally classified in the genus Myxosarcina and designated Myxosarcina sp. KIOST-1. These findings will help to advance our understanding of the cyanobacterial diversity in mangrove forest.