Heterocyte-forming cyanobacteria from Brazilian saline-alkaline lakes

Abstract

Studies investigating the diversity of cyanobacteria from tropical environments are scarce, especially those devoted to the isolation and molecular characterization of the isolated strains. Among the Brazilian biomes, Pantanal has mainly been examined through microscopic observation of environmental samples, resulting in lists of morphotypes without any genetic information. Recently, two studies were conducted evaluating the morphologic and genetic diversity of cultured non-heterocytous cyanobacteria in this biome, which resulted in the separation and description of two novel genera. In order to complement the diversity of cultured cyanobacteria from saline-alkaline lakes in Pantanal, the present study is dedicated to the examination of cultured nitrogen-fixing heterocytous cyanobacteria from this extreme and underexplored environment. A total of fourteen cyanobacterial strains were isolated. According to morphological examination they belong to the order Nostocales and to the subsections IV.I and IV.II, according to the International Code of Nomenclature for Algae, Fungi and Plants and the Bergey's Manual of Systematic Bacteriology, respectively. Phylogenetic evaluation of their 16S rRNA gene sequences resulted in the formation of five clusters. Among them, one is clearly related to the genus Anabaenopsis whilst the remaining clusters may represent new genetic lineages. These novel sequences aid in the delimitation of problematic groups, especially those containing sequences belonging to mixed genera. The application of both morphologic and phylogenetic studies has proven to be an important tool in resolving problematic groups in cyanobacteria systematics. This strategy is essential in order to detect novel cyanobacteria genera from other tropical environments.

Production of High Amounts of Hepatotoxin Nodularin and New Protease Inhibitors Pseudospumigins by the Brazilian Benthic Nostoc sp. CENA543

“…Morphological evaluations have shown that the cyanobacterial strain CENA543 belong to the genera Nostoc (Genuário et al, 2017 ). In a phylogenetic tree based on 16S rRNA (Figure 9 ), Nostoc sp.…”

“…The cyanobacterial strains studied were isolated from water samples that had been collected from several saline-alkaline lakes located at Centenário farm in the southern part of the sub-region Nhecolândia in the north of the municipality of Aquidauana, Mato Grosso do Sul State, Brazil (Andreote et al, 2014 ; Genuário et al, 2017 ; Figure S1 ). The Nostoc sp.…”

Biogeochemical diversity and hot moments of GHG emissions from shallow alkaline lakes in the Pantanal of Nhecolândia, Brazil

“…Usually, the most extreme cyanobacterial blooms are found during the driest period (August to November), with the highest alkalinity, EC and temperature values (Santos et al, 2011). Two major bloom-forming cyanobacterium have been identified (Andreote et al, 2014;Costa et al, 2016;Genuário et al, 2017;Vaz et al, 2015), Anabaenopsis elenikinii and Arthrospira platensis, primary producer (halo)alkaliphilic oxygenic cyanobacteria (Sorokin et al, 2015) that fix inorganic carbon and produce oxygen. These blooms occur during the 5 dry season and disappear in a few hours after the first heavy rains of the wet season.…”

Description of novel species of Aliinostoc, Desikacharya and Desmonostoc using a polyphasic approach

“…The genus Aliinostoc, the members of which showed morphological characters similar to members of the true Nostoc, was described by Bagchi et al [4] on the basis of its distant phylogenetic positioning from Nostoc sensu stricto. At present, majority of the strains of the genus Aliinostoc have been reported from tropical regions, except strains PCC 8122 and PCC 8976 that were reported from USA and France respectively [10][11][12]. The members of the genus Aliinostoc are usually found in habitats that are rich in dissolved salts and ions.…”