[Change of oil-degrading activity in microorganisms stored under laboratory conditions].

Change of the oil-degrading activity was studied in psychrophilic microbial strains Rhodococcus spp. DS-07, DS-21 and Pseudomonas spp. DS-09, DS-22 maintained on various media: rich and synthetic with a selective agent. After 2.5 years of storage on rich medium, the oil-degrading activity decreased by 50-60%, whereas this decrease was insignificant in the medium with oil. Passages to selective medium with oil after the storage partly restored the activity. It was found that storage of oil-degrading microorganisms caused loss of biodegradation plasmids. Their recovery and long-term preservation demand the presence of the selective agent in the medium.

[Selection of microorganisms capable of degrading petroleum and petroleum products at decreased temperatures]. / Otbor mikroorganizmov, sposobnykh k destruktsii nefti i nefteproduktov pri ponizhennykh temperaturakh.

Of 150 cultures capable of degrading petroleum at +6 degrees C, 40 strains growing in the liquid mineral nutrient medium containing petroleum (2%) as a sole source of carbon were selected. Of them, 13 cultures displaying a petroleum degradation rate exceeding 25% were selected. Abilities of these cultures and their associations to utilize fuel oil and its components--oils and benzene resins--were studied. The culture exhibiting degradation rates of fuel oil, its oils, benzene resins, and petroleum amounting to 17, 26, 10, and 51%, respectively, was selected. This culture can be used for cleanup of petroleum pollution under cold climatic conditions.

[Biodegradation of oil products by degrader strains and their associations in liquid media]. / Biodegradatsiia nefteproduktov shtammami-destruktorami i ikh assotsiatsiiami v zhidkoi srede.

The degrading activities of selected bacterial strains and their associations directed towards fuel oil and diesel fuel in liquid media were studied. Two-member associations composed preferably by Rhodococcus and Pseudomonas strains demonstrated the highest degrading efficiencies. No enhancement was achieved when the number of association members was increased to three, four, or five strains. The population stability of any member strain was found to depend on the association composition.

[Biosynthesis of somatotropin in a recombinant strain of Escherichia coli]. / Biosintez somatotropina rekombinantnym shtammom Escherichia coli.

A recombinant Escherichia coli K-12 strain was grown in the regime of chemostat with glucose limitation at a different flow rate and in the regime of turbidostat. The stability of its population and the dynamics of somatotropin biosynthesis were studied. The plasmid-containing strain became less stable as the flow rate in the fermenter dropped down, which was due, apparently, to a greater limitation. The level of somatotropin biosynthesis was higher at a low dilution rate (D = 0.075, 0.17 and 0.34 h-1). Possible factors responsible for this phenomenon are discussed.

Absence of glucose-stimulated transport in yeast protoplasts.

Protoplasts of Saccharomyces cerevisiae prepared by snail-gut juice treatment were compared in their transport properties with intact cells. 1. Constitutive monosaccharide transport (D-xylose, 6-deoxy-D-glucose), as well as inducible transport of D-galactose, were unaltered. 2. Phosphorylation-associated transport of 2-deoxy-D-glucose was enhanced in protoplasts, possibly as a consequence of removal of the unstirred layer of the cell wall. 3. Proton-driven transports of trehalose, L-leucine, L-proline and monophosphate could not be activated by preincubation with D-glucose, apparently owing to lack of proton-solute coupling in transport. Utilization of glucose was not depressed but respiration was reduced by about 50% while acidification of the external medium after glucose addition was inhibited by more than 90%. This may be related to the inability of protoplast plasma membrane H-ATPase to be activated by glucose and hence to impaired proton-translocating capacity. Uranyl ions inhibited generally much less in protoplasts than in intact cells although their binding to protoplasts was greater (maximum 0.68 fmol per cell but 3.2 fmol per protoplast).

[Differentiation of the genera of coryneform bacteria synthesizing amino acids and nucleotides]. / Differentsiatsiia rodov korinepodobnykh bakterii, sinteziruiushchikh aminokisloty i nukleotidy.

The morphological, cultural, physio-biochemical and chemotaxonomic properties as well as the content of GC in DNA were studied in coryneform bacterial strains producing amino acids and nucleotides. It has been shown that Brevibacterium ammoniagenes VKM 672, B. flavum 317A, B. stationis CCM 317 and Corynebacterium VSTI 301 should be assigned to the genus Corynebacterium. The taxonomic significance of chemotaxonomic and physio-biochemical properties is discussed on the basis of the results obtained and the data reported in literature. Apparently, coryneform bacterial genera having such chemotaxonomic properties as meso-DAPA, arabinose galactose and mycolic acids are related, and their physio-biochemical characteristics reflect the evolutionary development of coryneform bacterial groups in the course of which they have adapted to various ecological niches.

[Ratio of coryneform bacteria to the organic substance concentration]. / Otnoshenie korinepodobnykh bakterii k kontsentratsii organicheskogo veshchestva.

The effect of various organic substances and their concentrations on growth was studied with 10 strains of coryneform bacteria belonging to different taxonomic groups. The dynamics of the cultural growth depended on the nature of a substrate, glucose or acetate. Arthrobacter globiformis 281, A. variabilis 289, Nocardia erythropolis 236, N. globerula 502, N. minima 311 and N. rhodochrous 435 had a higher growth rate on acetate than on glucose. A. pascens 284, Brevibacterium ammoniagenes 334, Corynebacterium aquaticum 459 and C. michiganense 302 grew in a medium with glucose but not in a medium with acetate. The dependence of the maximal specific growth rate on the initial concentration of a carbon source was characterized, for all of the cultures, by high threshold concentrations of substrates (0.05--0.02 g per litre) and high Ks values (0.1--1.5 g per litre) which varied depending on the culture and the substrate. The dependence mu max = f(Cs) varied among different cultures and obeyed the Mono's equation only for B. ammoniagenes 334, C. aquaticum 459 and C. michiganense 302. The results presented here are in agreement with the assumption that some coryneforms isolated from oligotrophic habitats may occupy the ecological niche of the dissipation microflora.

[Morphologic and physiologic-biochemical characteristics of Kurthia zopfii]. / Morfologicheskaia i fiziologo-biokhimicheskaia kharakteristika Kurthia zopfii.

Comparative studies were made employing thirteen new isolates of Kurthia zopfii and strain ATCC 10538. It was shown that the cell wall of K. zopfii contained lysine, glycine, alanine, leucine, valine, aspartic and glutamic acids, ribose. The guanine plus cytosine content of deoxyribonucleic acid was 37-38 mol%. The simple post-fission cell movement was demonstrated. The obtained results are discussed against the practice of including the Kurthia into the group of coryneform bacteria.

[Carboxylation enzymes of coryneform bacteria]. / Fermenty karboksilirovaniia u korinepodobnykh bakterii.

The enzymes of carbon dioxide heterotrophic fixation were studied in six strains of coryneform bacteria belonging to the genera Arthrobacter, Brevibacterium, Corynebacterium and Nocardia. All of the strains were found to contain PEP (phosphoenolpyruvate) carboxylase (EC 4.1.1.31), NADP or NAD dependent malic enzymes (EC 1.1.1.38--40). Pyruvate carboxylase (EC 6.4.1.1) was found only in three strains of coryneforms: Brevibacterium ammoniagenes, Corynebacterium aquaticum and Nocardia erythropolis. PEP carboxykinase (EC 4.1.1.32) was detected in Brevibacterium ammoniagenes and Nocardia erythropolis. PEP carboxytransphosphorylase (EC 4.1.1.38) was found only in Brevibacterium ammoniagenes. These data suggest that carboxylation of C3-acids is one of the essential pathways in some coryneforms supplying the citric acid cycle with the products of glycolysis. The composition and the level of carboxylation enzymes reflect the ecological characteristics of the organisms rather than their taxonomical relations.

[Enzymes of intermediary metabolism in coryneform bacteria]. / Fermenty promezhutochnogo metabolizma u korinepodobnykh bakterii.

Enzymes of the intermediate metabolism were studied in ten strains of Corynebacterium-like organisms belonging to the genera Arthrobacter, Brevibacterium, Corynebacterium and Nocardia. All of these were found to contain enzymes of the glycolytic pathway, and nine strains among ten had dehydrogenases of the pentose phosphate shunt. The activity of enzymes of the citric acid cycle was low: alpha-ketoglutarate dehydrogenase was not found in Arthrobacter, Corynebacterium, Brevibacterium linens and Nocardia minima. Eight strains possessed the activity of the key enzyme of the gamma-aminobutyrate shunt, i.e. gamma-aminobutyrate aminotransferase. The activity of enzymes of the glyoxylate shunt was found in nine strains, and their level was rather high even during growth on glucose. Therefore, it is possible to study the taxonomic structure of this group of microorganisms by analyzing the composition and the level of enzymes involved in the intermediate metabolism. The competence of the Brevibacterium genus is corroborated by the typical species Brevibact. linens, as well as the reality of saprophytic representatives of the Corynebacterium genus, and a special taxonomic position of the group Brevibact. ammoniagenes--Brevibact. stationis.

Differentiation of genera of the coryneform bacteria.

A scheme of the generic structure of the group of coryneform bacteria, including the genera Arthrobacter, Brevibacterium, Cellulomonas, Corynebacterium, and Rhodococcus, is suggested. Morphological, chemotaxonomic (presence and stereochemical form of diaminopimelic acid, lipid A, and L-arabinose), and physiological features were used as diagnostic criteria. The position of Microbacterum and Mycococcus and of coryneforms with a nocardial wall but giving a positive Hugh-Leifson anaerobic test, and also of Arthrobacter pascens, which may be identical with Mycoplana sp., remains uncertain.