Comparative analysis of space-time organization of biological systems in periodic and dialyzed cultures of <Emphasis Type="Italic">Synechococcus</Emphasis> sp. PCC 6301

Data on biopolymers, their distribution, and spatial order in whole cells and in a certain cell layer of the cyanobacterium Synechococcus sp. PCC 6301 culture grown under periodic and dialysis conditions were obtained by the method of internal reflection spectroscopy. The fundamental distinction between the types of culture behavior under these cultivation conditions was shown. A similar approach can be used for standard specification of limiting concentrations in laboratory conditions, test object standardization, and creation of a culture with maximum possible adaptation to variable environmental conditions.     

Formation of Phenolic Compounds in Apogeotropic Roots of Cycad Plants

Formation and location of phenolic compounds in apogeotropic roots (coralloid roots) were studied in six cycad species, which belong to the genera Cycas, Encephalartos, and Ceratozamia. Total contents of soluble phenolic compounds in coralloid roots in all species studied varied insignificantly, with except for Ceratozamia mexicana that accumulated three times higher amounts of phenolic compounds. Phenolic compounds were accumulated in cell walls of cortical parenchyma of coralloid roots, in intercellular spaces, and in specialized storage cells, found in all zones of apogeotropic roots. The greatest number of phenol-storing cells was situated in the cortical parenchyma of the central part of coralloid roots, adjacent to a zone where active symbiotic cyanobacteria were localized, and in the coralloid root basal region lacking viable forms of cyanobionts. It was suggested that phenolic compounds affect the formation of symbiosis between cyanobacteria and apogeotropic roots of cycad plants, as well as their metabolism.     

Conversion of stillage carbohydrates by associations of microorganisms immobilized on polymer matrices

Five prospective microbial associations for conversion of stillage carbohydrates (sugars and dextrins) to acetate have been isolated from natural and anthropogenic sources. The characteristics of biological treatment of the stillage containing up to 40 g of carbohydrates/L have been studied using the Tambukan Silt association immobilized on the polymer nonwoven fibrous organic matrices. The microorganism association immobilized on matrices forms bio-hybrid materials of different features depending on their nature. Maximum biomass of the microbial association accumulates in matrices 9.11 and 9.21, oxidizes stillage carbohydrates, and accumulates acetate in the medium creating its lower redox potential more efficiently than in other matrices. It is supposed that the formation of the bio-hybrid materials has resulted in the formation of specific bacterial systems differing in physical and biochemical properties due to the principal development of specific microbial cell groups.     

Possibilities of bioconversion of agricultural waste with the use of microalgae

A new methodology of biological treatment and conversion of farm waste (manure and wash water) with the use of intensively cultivated phototrophic microorganisms (microalgae) is reviewed. Criteria for selection of microalgae and peculiarities of their intensive cultivation for efficient removal of biogenic elements from and destruction of the organic components of the wastes as well as the possibilities of cost-effective utilization of the resulting microalgal biomass are considered. Advantages and drawbacks of the new methodology are compared with those of conventional anaerobic techniques. Special attention is paid to the integrated technologies combining the aerobic conversion methods with microalgal post-treatment.     

Community of Hydrocarbon-Oxidizing Bacteria in Petroleum Products on the Example of TS-1 Jet Fuel and AI-95 Gasoline

Applied Biochemistry and Microbiology - It was shown that the studied petroleum products, kerosene and gasoline, contain microfloccules of heterogeneous microbial biofilms, the cells of which are...     

Ion-exchange characteristics of the cell walls isolated from the thallus of the lichen <Emphasis Type="Italic">Peltigera aphthosa</Emphasis> (L.) Willd

Ion-exchange characteristics of the cell walls isolated from different zones of the foliose lichen Peltigera aphthosa (L.) Willd were determined. Four types of ionogenic groups were revealed in the thallus cell walls of P. aphthosa, namely amino groups, carboxylic groups of uronic acids, carboxylic groups of phenolic acids, and phenolic OH groups. They may participate in the ion-exchange reactions with the ions of the environment. The amount of ionogenic groups in P. aphthosa cell walls was found to depend on the zone and age of the thallus.     

Melafen action on the growth and physiological parameters of phototrophic and heterotrophic microorganisms

Melafen, a synthetic plant growth regulator, stimulates the growth of periodic cultures of cyanobacteria Anacystis nidulans and Anabaena variabilis and green microalgae Chlorella vulgaris by 30–80%, when applied within the concentration range of 10⁻⁸–10⁻⁶ M. If the melafen concentration lies out of this range, it is either ineffective or inhibits the growth of these microorganisms. The growth and development of green microalgae Dunaliella maritima are stimulated, and the cell growth of heterotrophic bacteria Pseudomonas diminuta is inhibited in a wide range of the increased melafen concentrations. This agent also stimulates the growth of dialyzed phototrophic cultures and the formation of heterocysts and vegetative cells in the filaments of Anabaena variabilis, increases the redox potential of a cultivation medium, and reduces a carbohydrate excretion from the cells of phototrophic microorganisms. It is supposed that melafen activates the processes of photosynthesis and atmospheric nitrogen fixation.     

A new subarctic strain of <Emphasis Type="Italic">Tetradesmus obliquus</Emphasis>—part I: identification and fatty acid profiling

We isolated a new subarctic strain Tetradesmus obliquus IPPAS S-2023 (Scenedesmaceae, Chlorophyceae) from rock baths in the White Sea. To verify its taxonomic assignment, internal transcribed spacer 2 (ITS2) of the strain was sequenced and its secondary structure was compared with predicted ITS2 secondary structures of Scenedesmaceae. The analysis of the ITS2 made it possible to assign the new strain IPPAS S-2023 to the species T. obliquus. The ultrastructural studies and energy-dispersive X-ray spectroscopy (EDX) analysis revealed a marked accumulation of vacuolar inclusions enriched in phosphorus and nitrogen (N) as well as cytoplasmiс oil bodies. Most of predicted properties of biodiesel derived from the fatty acids profile of the strain grown in the N-free medium complied with the requirements of European and American standards. The results suggest that the new subarctic strain T. obliquus IPPAS S-2023 is a promising candidate for nutrients biosequestration and for biodiesel production. In a companion paper, we assess its biomass production capability and suitability and demonstrated suitability of IPPAS S-2023 as a reference strain for studies on elevated CO₂ stress effects selection of carbon dioxide-tolerant microalgae by comparison with a CO₂-tolerant strain IPPAS S-2014.     

Screening of the culture media with different concentrations of nutrients for cultivation of the microalgae associated with the invertebrates of the White Sea

The growth and biomass accumulation of three microalgal strains of Desmodesmus (Scenedesmaceae, Chlorophyceae), 1Рm66В, 2Cl66E, and 3Dp86Е-1, isolated from the White Sea benthic invertebrates were studied under conditions of batch culture in different standard media (BG-11, Prat, Goldberg, Gromov, Tamiya, artificial seawater) and modified media. The culture condition, biomass accumulation, and uptake of nitrate and phosphate were recorded. A significant alkalization of the culture medium up to pH 10 has been observed during a vigorous growth of the microalgae. The most significant biomass accumulation has been recorded in BG-11 (in complete or modified medium with addition of artificial seawater), Tamiya, and Prat media. Addition of seawater did not affect the growth of Desmodesmus sp. in the nitrate-containing media, although that maintained growth of the microalgae in the nitrogen-lacking media without cell aggregation. The BG-11 medium appears suitable for isolation and cultivation of both symbiotic and free-living microalgae by all the tested features. The Prat medium is the best for maintaining the microalgal strains in living collection.     

pH and CO<Subscript>2</Subscript> effects on <Emphasis Type="Italic">Coelastrella</Emphasis> (<Emphasis Type="Italic">Scotiellopsis</Emphasis>) <Emphasis Type="Italic">rubescens</Emphasis> growth and metabolism

We studied effects of рН and СО₂ enrichment on the physiological condition and biochemical composition of a carotenogenic microalga Coelastrella (Scotiellopsis Vinatzer) rubescens Kaufnerová et Eliás (Scenedesmaceae, Sphaeropleales, Chlorophyceae), a promising source of natural astaxanthin. The microalga was grown at a constant pH (5, 6, 7 or 8) maintained by direct СО₂ injection. The air-sparged culture served as the control. Cell division rate and size, dry biomass productivity, the rates of nitrogen and phosphorus uptake as well as photosynthetic pigment and total lipid content and fatty acid composition were followed. С. rubescens possessed a narrow-range рН tolerance (the optimum рН 6–7). Under these conditions, the highest values of the maximum (1.0–1.1 1/day) and average (0.3–0.35 1/day) specific growth rate, chlorophyll а (4.8–4.9%) and total carotenoid dry weight percentages (1.7–1.8%) were recorded. Cell lipid fatty acid unsaturation index (1.851) and polyunsaturated fatty acid percentage (36–39%) and С18:3 ω3/С18:1 ω9 ratio (3.8–4.5) were also the highest under these conditions. A decline of рН to 5 brought about severe stress manifesting itself as a cell division cessation, photosynthetic apparatus reduction, two-fold increase in cell volume, accumulation of dry weight and lipids and a considerable decline in fatty acid unsaturation. Cultivation of С. rubescens without СО₂ enrichment resulted in a rapid alkalization of the medium to рН 9.5–10.5 impairing the physiological condition of the cells. Reasons of the deteriorative effects of suboptimal pH values on the physiological condition of C. rubescens are discussed.