[Ratio of metals during changes in the metabolism of photosynthetic bacteria]. / Sootnoshenie metallov pri izmenenii metabolizma fotosinteziruiushchikh bakterii.

The content of polyvalent metals was determined in the photosynthetic bacteria Rhodopseudomonas capsulata (Athiorhodaceae) and Chromatium vanda (Thiorhodaceae) isolated from the sediments of Lake Vanda in the Antarctic when the conditions of growth, photoheterophic and photoautotrophic, were changed. The ratio between Fe and Mn, Cu, V, Ni, Co, Cr was studied. The utilization of all polyvalent metals, Mn and Cr in particular, relatively increased in the conditions of autotrophic growth. Changes in the composition of bacterial cells (the content of protein, lipophilic substances, flavin) and their enzymatic activity (hydrogenases) were also assayed. Apparently, chemical composition may be used as a criterion for determining the taxonomy of organisms and the ecological conditions of their habitat.

[Photosynthesizing bacteria from the Wanda Lake (Antarctica)]. / Fotosinteziruiushchie bakterii iz ozera Vanda (Antarktida).

Photoautotrophic bacteria growing under anaerobic conditions in the light at 28 degrees C with carbon dioxide as a sole source of carbon were isolated from the ooze of the Vanda Lake at a depth of 68 m. The cells are rounded gram-negative rods, and form a dark-red pigment. The morphology and physiology of the cells were studied as well as absorption spectra of the cells and isolated pigments. The main maxima of absorption were found to be shifted to a short-wavelength region of the spectrum. This fact and peculiar conditions of their habitat as well as some other characteristics are the reasons why these bacteria are classed as a new species Chomatium vanda. As far as we know, this is the first description of photosynthetic bacteria inhabiting the Vanda Lake in the Antarctic.

[Possibility of using light of different wavelengths for growing Chromatium vinosum in heterotrophic conditions]. / Vozmozhnost' ispol'zovaniia sveta raznoi dliny volny dlia razvitiia Chromatium vinosum v geterotrofnykh usloviiakh.

The photoautotrophic purple sulphur bacterium Chronatium vinosum was found to be capable of heterotrophic growth under anaerobic conditions at the expense of light energy. No growth was detected under anaerobic conditions in the absence of light. The energy of monochromatic red light (715, 726, 739, 776, 815 nm) and green light (534 and 535 nm), as well as of green luminescent light (a broad maximum at 500-560 nm, a peak at 520 nm) and white light, was used by the bacterium for the growth under anaerobic conditions in the presence of acetic acid as a sole source of carbon. The rate of biosynthesis of the cellular matter, proteins and pigments (bacteriochlorophyll and carotenoids) was different depending on the spectrum: light having wavelengths of 534, 535 and 715 nm was favourable, and infrared light having a wavelength of 815 nm was most effective. The heterotrophic growth of the bacterium depended also on the intensity of light, the optimum energy being 14-10(3)-20-10(3) erg/cm2/sec.

[Concentration of polyvalent metals following a change in the metabolism of Chromatium vinosum]. / Soderzhanie polivalentnykh mettalov pri izmenenii metabolizma Chromatium vinosum.

The composition of polyvalent metals (Fe, Mn, Cu, Ti, Ni, Co, V, Cr) was compared during photoheterotrophous and autotrophous growth of Chromatium vinosum. A comparatively high content of Mn and Cr, i. e. metals whose amount increases in the course of evolution of photoautotrophous organisms, is typical of the bacterium after autotrophous growth. An increase in the concentration of Ti, i. e. a metal involved in the reduction reactions of the cells, is characteristic of photoheterotrophous growth. As metabolism changes, differences are found in the content of protein, lipophilic substances, thioesters, flavin, and in the hydrogenase activity. These differences are discussed with respect to the role of polyvalent metals in metabolism of Chromatium vinosum.

[Photosynthetic development of purple sulfur bacteria during illumination with green light]. / Fotosinteticheskoe razvitie purpurnykh sernykh bakterii pri osveshchenii zelenym svetom

The photosynthetic purple sulphur bacterium Chr. vinosum grows by assimilating carbon dioxide at the account of the energy of light of different spectral composition. Short wavelengths of physiological radiation, blue and green, the region of carotenoid absorption, as well as white light, are used by the bacterium for assimilation of carbon dioxide, biosynthesis of biomass, protein, and pigments. Therefore, the possibility of utilization of the energy of green light for bacterial photosynthesis was shown for the first time. Blue light is more favourable for growth of the bacterium than green light is, provided the energy (in ergs or incident quanta) is the same. An increase in the intensity both of long and short wavelength radiation activates biomass accumulation and CO2 assimilation. Photosynthetic growth of the bacterium during its illumination with wavelengths of 464, 497, and 535 nm etc. which are similar to the absorption maxima of carotenoid pigments, suggests the participation of the latter in the uptake of energy that is necessary for photosynthesis.

[Microbiological studies of the Wanda Lake (Antarctica)]. / Mikrobiologicheskie issledovaniia ozera Vanda (Antarktida)

The deep-water (68 m) Wanda Lake in the Antarctica is noticeable by three characteristics: a relatively high temperature in the bottom layer, elevated salinity, and the presence of H2S. Only several (less often, dozens) saprophytic microorganisms per 40 ml of water are encountered in the lake. The total number of bacteria varies from 6-10(3) to 172-10(3) cells/ml. The highest content of the total bacterial population, and saprophytes, is found in intermediate layers, 30 and 40-50 m deep, respectively. Microbial strains isolated from water and ooze belong to the genera Pseudomonas, Chromobacterium, Bacillus, and Mycobacterium. Yeast organisms were also found. Sulphate reducing bacteria were detected only at one station in ooze of the lake while thionic bacteria could not be determined at all. Photosynthetic bacteria were isolated from ooze at all four stations.