A unicellular cyanobacterium, strain Alchichica-D10, was isolated from microbialites of the alkaline Lake Alchichica, Mexico. The cells were short rods (3.9 +/- 0.6 mum in length and 1.1 +/- 0.1 mum in width) forming biofilms of intense emerald green color. They exhibited red autofluorescence under UV light excitation. UV-visible absorption spectra revealed that they contain chlorophyll a and phycocyanin, and electron microscopy showed the presence of thylakoids. The strain grew within a temperature range of 15-30 degrees C. Genomic DNA G+C content was 52.2 mol%. The most remarkable feature of this species was its granular cytoplasm, due to the presence of numerous intracellular spherical granules (16-26 per cell) with an average diameter of 270 nm. These granules, easily visible under scanning electron microscopy, were composed of amorphous carbonate containing Ca, Mg, Ba, and Sr. A multi-gene phylogeny based on the analysis of 59 conserved protein markers supported robustly that this strain occupies a deep position in the cyanobacterial tree. Based on its phenotypic characters and phylogenetic position, strain Alchichica-D10 is considered to represent a new genus and novel species of cyanobacteria for which the name Gloeomargarita lithophora gen. nov., sp. nov. is proposed. The type strain is Alchichica-D10 (Culture Collection of Algae and Protozoa CCAP strain 1437/1; Collections de Cyanobacteries et Microalgues Vivantes of the Museum National d'Histoire Naturelle in Paris strain PMC 919.15). Furthermore, a new family, Gloeomargaritaceae, and a new order, Gloeoemargaritales, are proposed to accommodate this species under the International Code of Nomenclature for algae, fungi, and plants.
Moreira, David<br/>Tavera, Rosaluz<br/>Benzerara, Karim<br/>Skouri-Panet, Feriel<br/>Couradeau, Estelle<br/>Gerard, Emmanuelle<br/>Loussert Fonta, Celine<br/>Novelo, Eberto<br/>Zivanovic, Yvan<br/>Lopez-Garcia, Purificacion<br/>322669/European Research Council/International<br/>England<br/>International journal of systematic and evolutionary microbiology<br/>Int J Syst Evol Microbiol. 2016 Nov 21. doi: 10.1099/ijsem.0.001679.