[Development of hydrogen bacteria on hard surfaces]. / Razvitie vodorodnykh bakterii na tverdykh poverkhnostiakh.

A simple model system stimulating the physical conditions of hydrogen bacterial growth in soil and loose rocks was studied. Hydrogen bacterial cells grown under the autotrophic conditions were applied to the surface of coarse-grained silica gel, crushed brick and peat, and constantly supplied with a mixture of H2:O2:CO2 (7:2:1). It was shown that Nocardia opaca Z-766, when cultivated on well-developed solid surfaces with a small quantity of mineral medium, produced an active bacterial film at the whole surface and was capable of oxidizing hydrogen over 100 days. The rate of gas consumption had a maximum and then sharply decreased to a level of one-third--one-fifth of the maximal rate. The same was true of Pseudomonas carboxydoflava Z-352 and Nocardia autotrophica Z-1046; apparently, this is a common characteristic of all organisms growing on solid surfaces and fed with gases. The results suggest that microorganisms oxidizing hydrogen can grow on solid surfaces for a long period of time, serving as a bacterial filter which effectively removes a gaseous substrate.

[Isolation of an autotrophic variant of Nocardia opaca]. / Vydelenie avtotrofnogo varianta Nocardia opaca.

A hydrogen-oxidizing autotrophic actinomycete, strain Z-766, was isolated from the neuston of a marsh near Moscow. The organism was identified as Nocardia opaca Z-766 according to its morphologo-physiological properties. The spectrum of organic compounds used by the strain, its cultural characteristics and growth are similar to those of the monotypical autotrophic microorganism N. opaca 1b described earlier. Repeated isolation of the autotrophic variant of N. opaca Z-766 suggests that the ability of this species for autotrophic growth is not a unique phenomenon. It would be expedient to construct a taxon of the subspecial range, N. opaca var. autotrophica, for autotrophic variants of N. opaca.

[Systematic position of an autotrophic actinomycete isolated from a floodplain marsh near Moscow]. / Sistematicheskoe polozhenie avtotrofnogo aktinomitseta, vydelennogo iz nizinnogo bolota Podmoskov'ia.

A hydrogen-oxidizing actinomycete (Z-1046) was isolated from a flood-plain marsh in the Moscow Region. Its taxonomy was compared with that of similar cultures belonging to international special standards of actinomycetes (ISP). The strain Z-1046 was found to be identical with Streptomyces autotrophicus ISP-5011 (RIA-1008, ATCC-19727, CBS-466.68, IFO-12743). It has been also shown that the generic identification of the standard culture ISP-5011 is erroneous: as Hirsch (1960) holds, the culture belongs to the genus of Nocardia (Proactinomyces). Thus, the culture Streptomyces (Actinomyces) autotrophicus ISP-5011 must be eliminated from the international special standards of the genera Streptomyces and Streptoverticillium. The autotrophous actinomycete that we have isolated is classed as Proactinomyces autotrophicus comb. nov. (=Streptomyces autotrophicus Takamiya et Tubaki, 1956, ISP-5011, RIA-1008, ATCC-19727, CBS-466.68, IFO-12743, =Nocardia autotrophica, Hirsch, 1960).