Induction of Secondary Carotenogenesis in New Halophile Microalgae from the Genus Dunaliella (Chlorophyceae).

We report on the effects of high light irradiance (480 µmol quanta/(m(2)·s)) and salinity (160 and 200 g/liter NaCl) on culture growth as well as on cell lipid pigment and fatty acid (FA) composition in three novel strains of halophile microalga from the genus Dunaliella. Based on the ITS1-5.8S rRNA-ITS2 sequence and on the capability of accumulation of secondary (uncoupled from the photosynthetic apparatus) ß-carotene, the strains Dunaliella sp. BS1 and BS2 were identified as D. salina and Dunaliella sp. R5 as D. viridis. Under conditions optimal for growth, chlorophylls and primary carotenoids (mainly lutein) dominated the pigment profile of all investigated strains. The main FA were represented by unsaturated C18 FA typical of thylakoid membrane structural lipids. In all studied cells, stressors caused a decline in chlorophylls and an increase in unsaturated C16 and C18 FA associated with reserve lipids. The carotenogenic species D. salina demonstrated 10-fold increase in carotenoids accompanied by a decline in lutein and a drastic increase in ß-carotene (up to 75% of total carotenoids). In D. viridis, only 1.5-fold increase in carotenoid content took place, the ratio of major carotenoids remaining essentially unchanged. The role of the carotenogenic response in mechanisms of protection against photooxidative damage is discussed in view of halophile microalgae stress tolerance and application of the new Dunaliella strains for biotechnological production of ß-carotene.

[Antagonistic activity of novel green microalgae strain].

AIM: Screening of novel microalgae strains for the presence of pronounced antagonistic (antibacterial) activity against opportunistic bacteria. MATERIALS AND METHODS: 11 pure cultures of green unicellular algae isolated from fresh and salt basins of Orenburg region were studied for the presence of antagonistic activity against 4 test-strains of opportunistic bacteria by a photometric method. The effect of water extracts of microalgae Astermonas gracilis on the speed of self-purification of brine from Escherichia coli as well as antibacterial activity of peloid were evaluated under co-cultivation conditions. RESULTS: Pure cultures of green unicellular algae Scenedesmus obliquus (Turpin) Kütz, Scenedesmus magnus Meyen var. magnus, Pediastru duplex Meyen var. duplex, Chlorella vulgaris Bory, Monoraphidium arcuatum (Korschikov) Hindak (=Ankistrodesmus arcuatus Korschikov), Dictyosphaerium sp. had the most pronounced antagonistic activit against opportunistic bacteria. Water extract ofA. gracilis microalgae accelerated brine self-purification fro E. coli due to antibacterial effect. Peloid containing extracts of microorganism cells had a pronounced antibacterial effect against opportunistic bacteria. CONCLUSION: Antagonistic substances localized inside cells of microalgae increased the speed of allochthonic microorganism elimination that is one of the mechanisms of self-purification of a basin and antibacterial effect of peloid. The novel green microalgae strains studied due to the presence of pronounced antagonistic activity may have a wide practical application.

[Experimental interaction of halophilic prokaryotes and opportunistic bacteria in brine].

AIM: Study the effect of extremely halophilic archaea and moderately halophilic bacteria on preservation of opportunistic bacteria in brine. MATERIALS AND METHODS: 17 strains of moderately halophilic bacteria and 2 strains of extremely halophilic archaea were isolated from continental hypersaline lake Razval of Sol-Iletsk area of Orenburg Region. Identification of pure cultures of prokaryotes was carried out taking into account their phenotype properties and based on determination of 16S RNA gene sequence. The effect of halophilic prokaryote on elimination of Escherichia coli from brine was evaluated during co-cultivation. Antagonistic activity of cell extracts of the studied microorganisms was evaluated by photometric method. RESULTS: A more prolonged preservation of an E. coli strain in brine in the presence of live cells of extremely halophilic archaea Halorubrum tebenquichense and moderately halophilic bacteria Marinococcus halophilus was established. Extracts of cells of extremely halophilic archaea and moderately halophilic bacteria on the contrary displayed antagonistic activity. CONCLUSION: The protective effect of live cells of halophilic prokaryotes and antagonistic activity of their cell extracts change the period of conservation of opportunistic bacteria in brine that regulates inter-microbial interactions and changes the period of self-purification that reflects the sanitary condition of a hypersaline water body.

[Persistent properties of microorganisms inhabiting highly mineralized water bodies].

AIM: Study prevalence and intensity of persistent properties in bacteria inhabiting highly min eralized water bodies and determine their role in interaction with halophilous heterotrophic protozoa. MATERIALS AND METHODS: 300 bacteria strains and 3 cultures of heterotrophic protozo isolated from water bodies with mineralization of 2-350 g/l were studied. Antilysozyme (ALA) antihistone (AHA) activity of bacteria, protozoa lysozyme were evaluated by dish and photometric methods. Protozoa histones were evaluated cytochemically. Interaction of protozoa and Escherichia coli was evaluated by experimental co-cultivation. RESULTS: Presence of lysozyme an histones was shown in halophilous heterotrophic protozoa. Prevalence of ALA and AHA in bacteria was shown to increase as water body mineralization decreases. Intensity of E. colielimination from brine was determined to depend on the bacteria ALA level and phagocytic activity of protozoa. Participation of halotolerant protozoa in formation of heterogeneity of bacterial population by ALA was shown. CONCLUSION: In biocenoses of highly mineralized water bodies functioning of lysozyme-antilysozyme, histone-antihistone systems was shown. Bacteria with high persistent potential may impair sanitary parameters of highly mineralized water bodies, process of self-purification of which depends directly on phagocytic activity of protozoa.

[Regulation of symbiotic interactions in algobacterial associations].

AIM: To study mechanisms of survival and regulation of natural algobacterial associations. MATERIALS AND METHODS: Lysozyme, antilysozyme, catalase and antagonistic activity as well as hydrogen peroxide production were determined in algobacterial associations formed by green algae or cyanobacteria and satellite bacteria. For assessment of reactions of microbial interactions, derivates of Escherichia coli, which differ on the presence of antilysozyme and catalase signs, were used. RESULTS: Multidirectional effects of symbionts in biocenosis were revealed. Involvement of functional systems lysozyme-antilysozyme and hydrogen peroxide-catalase in regulation of associative interactions in algae-bacterial biocenosis was established. In conditions of antibacterial action of algae's hydrogen peroxide, catalase activity of associate bacteria provides survival of microorganisms in association with algae, whereas high level of catalase activity promotes domination of associate bacteria in algobacterial communities. Antagonistic activity allows the microalgae to suppress growth of undesirable microorganisms and regulate their number in algobacterial cenosis. CONCLUSION: Functional systems lysozyme-antilysozyme, hydrogen peroxide-catalase as well as antagonistic activity of symbionts form the basis for regulation of symbiotic interactions in associations of water microorganisms, which has ecological and sanitary-hygienic implications.

[Symbiosis in survival of microorganisms in hyperhaline water reservours].

Differently directed effects from autochthonous algae and bacteria on allochthonous microflora in hyperosmotic conditions were revealed and analyzed. Living halophilic microorganisms increase survival time of enterobacteria. Cellular extracts from halophils decrease storage time of allochthonous bacteria in a highly mineralized medium. Allochthonous bacteria in hyperosmotic conditions are able to suppress viability of autochthonous halophilic microflora. Symbiotic interactions between autochthonous and allochthonous microorganisms, defined by correlation of protective and antagonistic effects, regulate survival of microorganisms in hyperhaline water reservours and can be used for the assessment of their ecological and sanitary-and-hygienic states.

[Propagation of congenital anomalies of sexual development in the newborn population of Moscow]. / Izuchenie rasprostranennosti vrozhdennykh anomalii polovogo razvitiia u novorozhdennykh moskovskoi populiatsii.

The prevalence of congenital abnormalities of the genitals was estimated in newborns of the Moscow population in 1992 and 1993. The prevalence was found to be one case per 1500-1550 newborns. The pattern and structure of the observed pathology were studied. The range of patients who were not detected during the study, due to clinical peculiarities of their pathology, was estimated.

[Human alpha-satellite DNA specific to chromosomes 13 and 21: use for the analysis of polymorphism of acrocentric chromosomes and the origin of the additional chromosome 21 in Down's syndrome]. / Al'fa-satellitnaia DNK cheloveka so spetsifikoi dlia khromosom 13 i 21: ispol'zovanie dlia analiza polimorfizma akrotsentricheskikh khromosom i proiskhozhdeniia dopolnitel'noi khromosomy 21 pri bolezni Dauna.

Chromosomal distribution of cloned human alpha-satellite DNA alpha R1-6 has been studied by in situ hybridization technique. The sequence under study has been shown to be predominantly located in the centromeric regions of chromosomes 13 and 21. Intercellular variability of labelling patterns in every person under analysis being insignificant, there exists strong individual variability of interchromosomal distribution of the satellite. This variability leads to the differences of the chromosome labelling density (i.e. the number of satellite DNA copies) both between and within chromosome pairs. The difference in the copy number between two homologues chromosomes, 13 and 21 reaches up to 5 times. No correlation between nondisjunction and the number of copies of alpha-satellite DNA was found. Analysis of individual distribution of satellite between homologues of chromosome 21 provides new possibilities for determination of the origin of extra chromosome in the patients with trisomy 21.