Observations on the Genus Radiococcus, Family Chlorophyceae, a new Record for India

Volume: 99Start Page: 158End Page: 16

Phormidium etoshii sp. nov. (Oscillatoriales, Cyanobacteria) described from the Etosha Pan, Namibia, based on morphological, molecular and ecological features

An edaphic, filamentous, nonheterocytous cyanobacterium was collected from the Etosha Pan, Namibia. Based on multilocus sequencing of the 16S rRNA gene, beta and alpha subunits (cpcBA-IGS) of the phycocyanin operon and morphological and ecological features, we describe the new species Phormidium etoshii (Oscillatoriales). The taxon was differentiated from the phylogenetically closest taxa in morphological features and ecology. © Czech Phycological Society (2013)

Molecular detection of uncultured cyanobacteria and aminotransferase domains for cyanotoxin production in sediments of different Kenyan lakes

Abstract PCR-based denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene fragments was used to identify the cyanobacterial phylotypes in sediments and plankton of saline-alkaline and freshwater lakes of Kenya. The detection of the aminotransferase domain located on modules mcyE and ndaF using specific molecular markers confirmed the presence of potential toxin-producing cyanobacteria. The eight nucleotide sequences obtained from DGGE bands were placed in three divergent cyanobacterial clusters. Five nucleotide sequences were close to members of the genera Anabaenopsis and Umezakia (Nostocales), two sequences fell in the cluster with Arthrospira sp. (Oscillatoriales) and one sequence was related to Chroococcidiopsis sp. (Pleurocapsales). The presence of the latter taxon was demonstrated de novo in the investigated lakes. All nine attained nucleotide sequences of the aminotransferase region belonged to the mcyE module. Five sequences of the aminotransferase domain were included in the cluster having the nucleotide sequence of Anabaena sp. but showed a separate lineage. Other four aminotransferases were placed in the cluster represented by nucleotide sequence of Microcystis aeruginosa. To our knowledge, this is the first report on molecular detection of cyanobacterial phylotypes in sediments of African lakes and aminotransferase domains for cyanotoxin production from sediment samples in general

Genetic and morphologic characterization of four putative cylindrospermopsin producing species of the cyanobacterial genera Anabaena and Aphanizomenon

Cylindrospermopsin (CYN) is a potent hepatotoxic alkaloid that has been detected in freshwater samples worldwide and is produced by a number of cyanobacterial species, mainly of the genera Cylindrospermopsis, Aphanizomenon and Anabaena. Cylindrospermopsis raciborskii is a morphologically distinctive species which forms a genetically well-defined cluster. In contrast, some species within Aphanizomenon and Anabaena are morphologically not clearly assignable to either genera and both genera are polyphyletic. In the Cylindrospermopsis cluster CYN producing and non-producing strains co-occur, but it is not known if CYN producing and non-producing strains are closely related in Anabaena and Aphanizomenon. Here we attempt to disentangle the phylogenetic relationships of four taxa of the genera Anabaena and Aphanizomenon, some of which are known as CYN producers. We have sequenced and phylogenetically analysed partial sequences of the 16S rRNA gene, cpcBA-IGS and rpoC1 from 31 cyanobacteria isolates of the genera Aphanizomenon and Anabaena and have documented morphotypic characteristics of new and recently isolated strains. Our results do not corroborate the separation of Aph. gracile and Aph. flos-aquae into separate species. In contrast, they support the distinction of Ana. bergii and Aph. ovalisporum into distinct taxa. Further, Ana. bergii is most likely not a CYN producing species.

A <i>Piscibacillus</i> sp. Isolated from A Soda Lake Exhibits Anticancer Activity Against Breast Cancer MDA-MB-231 Cells

Microorganisms thrive in extreme environments and are known for synthesizing valuable metabolites. Salt-loving microorganisms can flourish in saline environments which inhibit the growth of other microbial life, and they possess the potential to produce stable and novel biomolecules for the use in biotechnological applications, including anticancer compounds. Sambhar Lake is the largest inland soda lake in India and is an appropriate habitat for halophilic bacterial and archaeal strains in terms of diversity and potential production of bioactive compounds. In the present study, a moderately halo-alkaliphilic bacterial strain C12A1 was isolated from Sambhar Lake, located in Rajasthan, India. C12A1 was gram-positive, motile, rod-shaped, formed oval endospores, produced carotenoids, and exhibited optimal growth at 37 &#176;C in 10&#8315;15% NaCl (pH 8). C12A1 was found to be able to hydrolyze skimmed milk, gelatin, and Tween 80 but unable to hydrolyze starch and carboxymethylcellulose. C12A1 showed 98.87% and 98.50% identity in 16S rRNA gene sequence to P. halophilus and P. salipiscarius, respectively. Nevertheless, C12A1 was clustered within the clade consisting of P. salipiscarius strains, but it showed a distinct lineage. Thus, C12A1 was designated as Piscibacillus sp. Cell proliferation assay results showed that C12A1 broth extract (BEP) decreased cell viability in breast cancer MDA-MB-231 cells, which was confirmed by the MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. Induction of cell toxicity was visualized by microscopy. Reverse Transcriptase PCR (RT-PCR) analysis demonstrated that BEP inhibited the expression of proliferative B-cell lymphoma-extra large (Bcl-xL) and cell cycle marker Cyclin-dependent kinase 2 (CDK2) at transcript levels. Similarly, cell migration and colony formation along with mesenchymal marker vimentin and stem cell marker BMI transcripts were found to be inhibited when cells were treated with the BEP. The anti-breast cancer potential of C12A1 indicates that microorganisms inhabiting saline-alkaline habitats, with Piscibacillus sp. in particular, are a promising source for discovery of novel bioactive substances