Description of two new species of Nostoc (Nostocales, Cyanobacteria) from central Mexico, using morphological, ecological, and molecular attributes

Abstract

The present study describes two new Nostoc species, N. montejanii and N. tlalocii, based on a polyphasic approach that combines morphological, ecological, and genetic characteristics. The five investigated populations, including those from newly collected material from central Mexico, were observed to possess morphological features characteristic of the Nostoc genus. Results showed that both new species are strictly associated with running water, and they show clear differences in their habitat preferences. The 16S rRNA gene sequences of the five strains displayed between 98% and 99% similarity to the genus Nostoc sensu stricto. The 16S rRNA gene phylogenetic analyses inferred using Bayesian inference, maximum likelihood, and parsimony methods, placed these five strains in two separate clades distinct from other Nostoc species. The secondary structures of the 16S–23S internal transcribed spacer rRNA region in the two new species showed >10.5% dissimilarities in the operons when compared with other Nostoc species. In addition, clear morphological differences were observed between the two Mexican species, including the color of the colonies (black in N. montejanii and green in N. tlalocii), the size of the cells (greater in N. montejanii), and the number of polyphosphate granules present in the cells (one in N. montejanii and up to four in N. tlalocii).

Cyanobacterial Harmful Algal Mats (CyanoHAMs) in tropical rivers of central Mexico and their potential risks through toxin production

“…tlalocii (BV = 100%), while the Tambaque population (BV = 53) represents N . montejanii (Carmona-Jiménez et al, 2023 ). Interestingly, populations from San Rafael and San Miguel showed morphological characteristics similar to Nostoc , but the phylogenetic analysis indicated that these belong to the Compactonostoc genus.…”

Polyphasic Approach and Potential Cyanotoxin Production by Planktothrix from the Río Grande de Comitán and Montebello Lakes National Park, Southern Mexico

“…The transformation process was carried out using 100 µ L of the competent bacteria strain Escherichia coli (DH5a) (Promega). The transformed bacteria were inoculated (250 μ L) in Petri dishes with solid LB medium [ 37 ], ampicillin (0.1 mg/mL), X-Gal: 5-bromo-4-chloro-3-indolyl- β -D-galactopyranoside (0.04 mg/mL), and IPTG: isopropyl- β -D-1-thiogalactopyranoside (0.5 mM) [ 38 ]. The cultures were incubated at 37°C for 24 hours.…”

“…Negative clones (blue colonies without insert) were discarded. The presence of the insert was confirmed by PCR and electrophoresis [ 38 ]. The reaction master mix used was the following: milli-Q water, 10x PCR buffer, Cl 2 Mg (50 mM), deoxyribonucleotide triphosphate (50 μ M dNTP), and DNA polymerase (Ultratools DNA Polymerase: 1 unit/ μ L and Thermo Scientific DreamTaq DNA Polymerase: 20 and 500 units/ μ l).…”

“…Afterward, the extraction and purification of the plasmids was carried out using the Wizard Plus SV Minipreps DNA Purification System Kit (Promega). Once the plasmid DNA was obtained, its concentration was measured (Epoch: BioTek Instruments Inc., USA), before finally be sent for sequencing [ 38 ]. The sequencing process was carried out at the DNA Synthesis and Sequencing Unit (USSDNA) of the Institute of Biotechnology-UNAM (National Autonomous University of Mexico) and the Complutense University of Madrid (Genomic Unit-CAI).…”