A novel freshwater strain of Coelastrella multistriata MZ–Ch23 was discovered in Tula region, Russia. The identification is based on morphological features, phylogenetic analysis of SSU rDNA gene and ITS1–5.8S rDNA–ITS2 region and predicted secondary structure of the ITS2. Phylogenetic analysis places the novel strain in the “core” Coelastrella clade within the Chlorophyceae. This is the first record of Coelastrella multistriata in the algal flora of Russia. Cultivation experiments were carried out to evaluate growth dynamics of the newly identified strain and the impact of nitrogen and/or phosphorus depletion on the fatty acid profiles and lipid productivity. On the fully supplemented Bold’s basal medium and under phosphorus-depleted conditions as well, the fatty acid profiles were dominated by α-linolenic acid (29.4–38.1% of total fatty acids). Depletion of either nitrogen or both nitrogen and phosphorus was associated with increased content of oleic acid (32.9–33.7%) and linoleic acid (11.9%). Prolongation of the growth to two months (instead of 25 days) resulted in increased content and diversity of very long-chain fatty acids including saturated species. The total very long-chain fatty acid content of 9.99% achieved in these experiments was 1.9–12.3-fold higher than in stress experiments. The highest variation was observed for oleic acid (3.4–33.7%). The novel strain showed the ability to accumulate lipids in amounts up to 639.8 mg L−1 under nitrogen and phosphorus starvation, which exceeds the previously obtained values for most Coelastrella strains. Thus, the newly identified MZ–Ch23 strain can be considered as a potential producer of omega-3 fatty acids on fully supplemented Bold’s basal medium or as a source of biomass with high content of saturated and monounsaturated fatty acids after nitrogen and phosphorus starvation.
A new cyanobacterial species of Aliinostoc, A. vietnamicum sp. nov., is recorded in the tropical forest soil from the C at Tiên National Park, Vietnam. The analysis is based on morphological characters, 16S rDNA phylogeny, ITS secondary structure, and fatty acid composition analysis. Aliinostoc vietnamicum differed from the other species of the genus by the size and shape of vegetative cells, size of akinetes and heterocytes, and presence of granular polyphosphate inclusions in vegetative cells. The evolutionary distance matrix based on the 16S rRNA gene shared 96.2-98.2% similarities with other Aliinostoc sequences. The phylogeny inferred by maximum likelihood and Bayesian inference placed A. vietnamicum in the Aliinostoc clade, within the Nostocaceae. For the first time, fatty acid composition analysis was obtained for a member of the genus Aliinostoc with cultivation time experiments. a-linolenic (27.54-37.75%), palmitic (13.87-22.65%), and stearic (10.08-20.27%) acids were the dominant fatty acids when cultured during the exponential growth phase, as well as during stationary. This is the first finding of a strain with such a high content of stearic acid among cyanobacteria with Nostoc-like morphology.
We studied the morphology, ultrastructure, and phylogeny of eight soil diatom strains assigned to the Pinnularia genus. Six of these strains, identified by us as new species, are described for the first time. We provide a comprehensive comparison with related species and include ecological data. Molecular phylogeny reconstruction using 18S rDNA and rbcL affiliates the new strains with different subclades within Pinnularia, including ‘borealis’, ‘grunowii’ and ‘stomatophora’. We also studied the fatty acid profiles in connection with the emerging biotechnological value of diatoms as a source of lipids. Stearic (36.0–64.4%), palmitic (20.1–30.4%), and palmitoleic (up to 20.8%) acids were the dominant fatty acids in the algae cultured on Waris-H + Si medium. High yields of saturated and monounsaturated fatty acids position the novel Pinnularia strains as a promising feedstock for biofuel production.
We describe a new member from the genus Navicula Bory sensu stricto using light and scanning electron microscopy. The new species was found in Vietnam, and is a large-celled species with longitudinal grooves present on the valve exterior. Taxa sharing this feature are known from the genus Navicula, as well as the genera Haslea Simonsen, Craticula Grunow, Gyrosigma Hassall and Proschkinia Karajeva. The new species from Vietnam is compared with other, similar taxa of Navicula, and comments are presented about the systematics and biogeography of the group of Navicula species with this characteristic feature.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.