Differential Membrane Lipid Profiles and Vibrational Spectra of Three Edaphic Algae and One Cyanobacterium

The membrane glycerolipids of four phototrophs that were isolated from an edaphic assemblage were determined by UPLC–MS after cultivation in a laboratory growth chamber. Identification was carried out by 18S and 16S rDNA sequencing. The algal species were Klebsormidium flaccidum (Charophyta), Oocystis sp. (Chlorophyta), and Haslea spicula (Bacillariophyta), and the cyanobacterium was Microcoleus vaginatus (Cyanobacteria). The glycerolipid profile of Oocystis sp. was dominated by monogalactosyldiacylglycerol (MGDG) species, with MGDG(18:3/16:4) accounting for 68.6%, whereas MGDG(18:3/16:3) was the most abundant glycerolipid in K. flaccidum (50.1%). A ratio of digalactosyldiacylglycerol (DGDG) species to MGDG species (DGDG/MGDG) was shown to be higher in K. flaccidum (0.26) than in Oocystis sp. (0.14). This ratio increased under high light (HL) as compared to low light (LL) in all the organisms, with its highest value being shown in cyanobacterium (0.38–0.58, LL−HL). High contents of eicosapentaenoic acid (EPA, C20:5) and hexadecenoic acid were observed in the glycerolipids of H. spicula. Similar Fourier transform infrared (FTIR) and Raman spectra were found for K. flaccidum and Oocystis sp. Specific bands at 1629.06 and 1582.78 cm−1 were shown by M. vaginatus in the Raman spectra. Conversely, specific bands in the FTIR spectrum were observed for H. spicula at 1143 and 1744 cm−1. The results of this study point out differences in the membrane lipid composition between species, which likely reflects their different morphology and evolutionary patterns.

Chemometrics-Assisted Identification of Anti-Inflammatory Compounds from the Green Alga Klebsormidium flaccidum var. zivo

The green alga Klebsormidium flaccidum var. zivo is a rich source of proteins, polyphenols, and bioactive small-molecule compounds. An approach involving chromatographic fractionation, anti-inflammatory activity testing, ultrahigh performance liquid chromatography-mass spectrometry profiling, chemometric analysis, and subsequent MS-oriented isolation was employed to rapidly identify its small-molecule anti-inflammatory compounds including hydroxylated fatty acids, chlorophyll-derived pheophorbides, carotenoids, and glycoglycerolipids. Pheophorbide a, which decreased intracellular nitric oxide production by inhibiting inducible nitric oxide synthase, was the most potent compound identified with an IC50 value of 0.24 µM in lipopolysaccharides-induced macrophages. It also inhibited nuclear factor kappaB activation with an IC50 value of 32.1 µM in phorbol 12-myristate 13-acetate-induced chondrocytes. Compared to conventional bioassay-guided fractionation, this approach is more efficient for rapid identification of multiple chemical classes of bioactive compounds from a complex natural product mixture.

Purification of microalgae crops of ACKU collection from fungal contaminants

The work is focused to the selection of the best purification methods of microalgae strains from ACKU collection (Algae Culture Collection of Kyiv University) from contamination by microscopic fungi. The screening of microalgae culture collection ACKU (Algae Culture Collection of Kyiv University) is deal. Contamination of some microalgae strains by fungi of Cladosporium Link, Alternaria Nees, and Monilia Bonord genera was detected. The following strains were selected for the experiment: ACKU 139-02 (Klebsormidium flaccidum (Kütz.) PC Silva, Mattox et Blackwell), ACKU 293-04 (Acutodesmus obliquus (Turpin) P. Tsarenko), ACKU 364-04 (cf. Chlorosarcinopsis dissociata Herndon), ACKU 599-06 (Klebsormidium nitens Menegh. in Kützing), ACKU 600-06 (Klebsormidium flaccidum (Kütz.) PC Silva, Mattox et Blackwell) и ACKU 1056 (Desmodesmus abundans (Kirchn.) E. Hegew.). The effect of carbendazim (Methylbenzimidazol-2-ylcarbamate), Antibiotic Antimycotic Solution (penicillin – 10,000 IU, streptomycin – 10 mg, amphotericin B – 25 μg) and Nuosept BMc 422 on fungi-contaminants of green algal culture strains with different morphological structure (coccoid and filamentous) was studied. Experimental concentrations of substances: carbendazim – 0.005%, Antibiotic Antimycotic Solution – 1%, Nuosept BMc 422 – 0.05% and 0.2%. Was shown that Antibiotic-Antimycotic Solution and Nuosept BMc-422 at the selected concentrations were not effective for purifying of green algae strains from significant contamination by microscopic fungi. It was found that the carbendazim solution is effective in the purification of cocoid green algae strains from contamination by microscopic fungi Cladosporium cladosporioides (Fresen.) G.A. de Vries). As a result, an axenic culture was obtained for the ACKU strain No.293-04 (A. obliquus).

Xylans of Red and Green Algae: What Is Known about Their Structures and How They Are Synthesised?

Xylans with a variety of structures have been characterised in green algae, including chlorophytes (Chlorophyta) and charophytes (in the Streptophyta), and red algae (Rhodophyta). Substituted 1,4-β-d-xylans, similar to those in land plants (embryophytes), occur in the cell wall matrix of advanced orders of charophyte green algae. Small proportions of 1,4-β-d-xylans have also been found in the cell walls of some chlorophyte green algae and red algae but have not been well characterised. 1,3-β-d-Xylans occur as triple helices in microfibrils in the cell walls of chlorophyte algae in the order Bryopsidales and of red algae in the order Bangiales. 1,3;1,4-β-d-Xylans occur in the cell wall matrix of red algae in the orders Palmariales and Nemaliales. In the angiosperm Arabidopsis thaliana, the gene IRX10 encodes a xylan 1,4-β-d-xylosyltranferase (xylan synthase), and, when heterologously expressed, this protein catalysed the production of the backbone of 1,4-β-d-xylans. An orthologous gene from the charophyte green alga Klebsormidium flaccidum, when heterologously expressed, produced a similar protein that was also able to catalyse the production of the backbone of 1,4-β-d-xylans. Indeed, it is considered that land plant xylans evolved from xylans in ancestral charophyte green algae. However, nothing is known about the biosynthesis of the different xylans found in chlorophyte green algae and red algae. There is, thus, an urgent need to identify the genes and enzymes involved.