Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 39
Filter
Add more filters










Publication year range
1.
Article in Russian | MEDLINE | ID: mdl-34486848

ABSTRACT

The analysis of international data established that the national indicator of population health quality in the Russian Federation is significantly lower than in the EU, the USA and Canada. In this regard, the urgency of enhancement of state policy concerning updating and promoting development of national health care system,involving available resources of the public and private health sectors is obvious. The development of entrepreneurship in health care should be considered as a mean of improving social and economic efficiency of health care system in Russia. The purpose of study was to analyze perspective directions of development of entrepreneurial initiatives in national health care. On the basis of analysis of corresponding normative legal acts and publications, it is demonstrated that in national health care system prerequisites are establishing to implement new opportunities for patient-oriented entrepreneurial activities associated with development of digital technologies, e-Health, new forms of public-private partnership focused primarily on prevention and rehabilitation of patients.


Subject(s)
Delivery of Health Care , Entrepreneurship , Humans , Private Sector , Prospective Studies , Russia
2.
Mikrobiologiia ; 82(6): 681-90, 2013.
Article in Russian | MEDLINE | ID: mdl-25509406

ABSTRACT

A mesophilic hydrogenotrophic methanogenic archaeon, strain Z-7105(T), was isolated from the bottom sediments of a collector in the vicinity of a soda lake Tanatar II (Altai, Russia). The cells were motile, irregular cocci 0.2-1.2 µm in diameter. The organism was an obligate alkaliphile, growing within a pH range from 8.0 to 10.2 with the optimum at pH 9.0-9.5. It was obligately dependent on carbonates, growing at 0.5 to 1.6 M total carbonates with the optimum at 0.7-0.9 M. Sodium ions were also obligately required at concentrations from 0.9 to 3.3 M Na+ (optimum at 1.4-1.9 M). The organism was halotolerant, but Cl- ions were not required. Hydrogen and formate were used as electron donors. Acetate was required for anabolism. The DNA G + C content was 50.2 mol %. According to the results of its 16S rRNA gene sequence analysis, the isolate belonged to the genus Methanocalculus, being the first known alkaliphilic member of this genus. Its similarity to the neutrophilic and halotolerant Methanocalculus species (M. halotolerans, M. taiwanensis, M. pumilus, and M. chunghsingensis) was 98.2-97.1%, which is within the interspecific range for this genus. The level of DNA-DNA hybridization between strain Z-7105(T) and the Methanocalculus type species M. halotolerans DSM 14092(T) was 32%. The genus Methanocalculus, including the new isolate and the previously described species, is distant from other genera of methanogens (< 90% 16S rRNA gene similarity). Based on significant phenotypic differences and the results of phylogenetic analysis, including DNA-DNA hybridization, it is proposed to assign strain Z-7105(T) (= DSM 25006(T), = VKM B-2765(T)) to the new species Methanocalculus natronophilus sp. nov. and to incorporate the genus into the new family Methanocalculaceae fam. nov.


Subject(s)
Lakes/microbiology , Methanomicrobiaceae , Water Microbiology , Methanomicrobiaceae/classification , Methanomicrobiaceae/genetics , Methanomicrobiaceae/isolation & purification , Siberia
6.
Mikrobiologiia ; 77(4): 472-82, 2008.
Article in Russian | MEDLINE | ID: mdl-18825973

ABSTRACT

Soda lakes are characterized by an intense sulfur cycle that begins with sulfidogenesis. Model laboratory experiments that involved combining of pure cultures showed that, during anaerobic decomposition of cellulose by Clostridium alkalicellulosi, the sulfate-reducing bacteria (SRB) of the species Desulfonatronovibrio hydrogenovorans, Desulfonatronum lacustre, and Desulfonatronum cooperativum, different in their nutritional requirements, may directly use the cellulose fermentation products for sulfidogenesis without mediatory microorgansims. In binary cocultures with SRB, the amount of the H2S formed constituted from one-third to two-thirds of the cellulose [H] equivalents; acetate was among the products formed. When the syntrophic Contubernalis alkalaceticum, capable of acetate oxidation, was incorporated into the trophic chain along with hydrogenotrophic SRB, the amount of the H2S formed exceeded by 33-42% the amount of the [H] equivalents in the utilized cellulose, water being the source of additional hydrogen. Thus, the trophic pathway from plant residues to sulfide, previously considered to be the longest in the alkaliphilic microbial community, may involve a minimal number of stages and do without intermediate participation of dissipotrophic fermenters.


Subject(s)
Cellulose/metabolism , Clostridium/metabolism , Deltaproteobacteria/metabolism , Sulfides/metabolism , Alkalies/metabolism , Clostridium/growth & development , Coculture Techniques , Deltaproteobacteria/growth & development , Fermentation , Fresh Water/chemistry , Fresh Water/microbiology , Water Microbiology
7.
Mikrobiologiia ; 76(6): 834-43, 2007.
Article in Russian | MEDLINE | ID: mdl-18297876

ABSTRACT

In the course of the search for N2O-utilizing microorganisms, two novel strains of haloalkaliphilic denitrifying bacteria, Z-7009 and AIR-2, were isolated from soda lakes of Mongolia and Kenya. These microorganisms are true alkaliphiles and grow in the pH ranges of 8.0-10.5 and 7.5-10.6, respectively. They are facultative anaerobes with an oxidative type of metabolism, able to utilize a wide range of organic substrates and reduce nitrate, nitrous oxide, and, to a lesser extent, nitrite to gaseous nitrogen. They can oxidize sulfide in the presence of acetate as the carbon source and nitrous oxide (strain Z-7009) or nitrate (strain AIR-2) as the electron acceptor. The strains require Na+ ions. They grow at medium mineralization levels of 0.16-2.2 M Na+ (Z-7009) and 0.04-2.2 M Na+ (AIR-2). The G+C contents of the DNA of strains Z-7009 and AIR-2 are 67.9 and 65.5 mol %, respectively. According to the results of 16S rRNA gene sequencing and DNA-DNA hybridization, as well as on the basis of physiological properties, the strains were classified as new species of the genus Halomonas: Halomonas mongoliensis, with the type strain Z-7009T (=DSM 17332, =VKM B2353), and Halomonas kenyensis, with the type strain AIR-2T (=DSM 17331, =VKM B2354).


Subject(s)
Halomonas/isolation & purification , Halomonas/physiology , Nitrous Oxide/metabolism , Base Composition , Culture Media , DNA, Bacterial/genetics , Gases/metabolism , Halomonas/classification , Hydrogen-Ion Concentration , Kenya , Mongolia , Nitrates/metabolism , Nitrogen/metabolism , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Temperature , Water Microbiology
8.
Extremophiles ; 10(1): 53-60, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16193230

ABSTRACT

The cellulolytic activity of an alkaliphilic obligate anaerobic bacterium, Z-7026, which was isolated from the microbial community of soda-lake sediments and belongs to the cluster III of Clostridia with low G+C content, was studied. The bacterium was capable of growing in media with cellulose or cellobiose as the sole energy sources. Its maximal growth rate on cellobiose (0.042-0.046 h(-1)) was observed at an initial pH value of 8.5-9.0, whereas the maximal rate of cellulase synthesis, assayed by using a novel fluorimetric approach, was found to be 0.1 h(-1) at pH 8-8.5. Secreted proteins revealed high affinity for cellulose and were represented by two major forms of molecular masses of 75 and 84 kDa, whereas the general protein composition of the precipitated and cellulose-bound preparations was similar to cellulosome subunits of Clostridium thermocellum. The optimum pH of the partially purified enzyme preparation towards both amorphous and crystalline cellulose was in the range 6-9, with more than 70% and less than 50% of maximal activity being retained at pH 9.2 and 5.0, respectively.


Subject(s)
Bacteria, Anaerobic/enzymology , Cellulase/metabolism , Bacteria, Anaerobic/growth & development , Bacteria, Anaerobic/isolation & purification , Bacterial Proteins/biosynthesis , Cellulase/chemistry , Cellulase/isolation & purification , Cellulose , Chemical Precipitation , Chromatography, Gel , Clostridium , Geologic Sediments/microbiology , Hydrogen-Ion Concentration , Kinetics , Molecular Weight
9.
Mikrobiologiia ; 74(5): 642-53, 2005.
Article in Russian | MEDLINE | ID: mdl-16315983

ABSTRACT

The first anaerobic alkaliphilic cellulolytic microorganism has been isolated from the Verkhnee Beloe soda lake (Buryatiya, Russia) with pH 10.2 and a salt content of up to 24 g/l. Five strains were characterized. Strain Z-7026 was chosen as the type strain. The cells of the isolate are gram-positive spore-forming rods. A mucous external capsule is produced. The microorganism is obligately alkaliphilic, growing in a pH range of 8.0-10.2, with an optimum at pH 9.0. Sodium ions and, in carbonate-buffered media, sodium chloride are obligately required. The microorganism is slightly halophilic; it grows at 0.017-0.4 M Na+ with an optimum at 0.15-0.3 M Na+. The metabolism is fermentative and strictly anaerobic. Cellulose, cellobiose, and xylan can be used as growth substrates. Plant and algal debris can be fermented. Lactate, ethanol, acetate, hydrogen, and traces of formate are produced during cellulose or cellobiose fermentation. Yeast extract or vitamins are required for anabolic purposes. The microorganism fixes dinitrogen and is nitrogenase-positive. It is tolerant to up to 48 mM Na2S. Growth is not inhibited by kanamycin or neomycin. Chloramphenicol, streptomycin, penicillin, ampicillin, ampiox, bacillin, novobiocin, and bacitracin suppress growth. The DNA G+C content is 29.9 mol %. According to the nucleotide sequence of its 16S rRNA gene, strain Z-7026 is phylogenetically close to the neutrophilic cellulolytic bacteria Clostridium thermocellum (95.5%), C. aldrichii (94.9%), and Acetivibrio cellulolyticus (94.8%). It is proposed as a new species: Clostridium alkalicellum sp. nov.


Subject(s)
Cellulose/metabolism , Clostridium/isolation & purification , Clostridium/physiology , Fresh Water/microbiology , Water Microbiology , Anaerobiosis , Anti-Bacterial Agents/pharmacology , Base Composition , Chloramphenicol/pharmacology , Clostridium/classification , Clostridium/drug effects , Culture Media , DNA, Bacterial/genetics , Fermentation , Hydrogen-Ion Concentration , Molecular Sequence Data , Nitrogenase/metabolism , Phylogeny , RNA, Bacterial/analysis , RNA, Ribosomal, 16S/analysis , Russia , Species Specificity , Substrate Specificity
10.
Mikrobiologiia ; 74(6): 800-9, 2005.
Article in Russian | MEDLINE | ID: mdl-16400991

ABSTRACT

From the silty sediments of the Khadyn soda lake (Tuva), a binary sulfidogenic bacterial association capable of syntrophic acetate oxidation at pH 10.0 was isolated. An obligately syntrophic, gram-positive, spore-forming alkaliphilic rod-shaped bacterium performs acetate oxidation in a syntrophic association with a hydrogenotrophic, alkaliphilic sulfate-reducing bacterium; the latter organism was previously isolated and characterized as the new species Desulfonatronum cooperativum. Other sulfate-reducing bacteria of the genera Desulfonatronum and Desulfonatronovibrio can also act as the hydrogenotrophic partner. Apart from acetate, the syntrophic culture can oxidize ethanol, propanol, isopropanol, serine, fructose, and isobutyric acid. Selective amplification of 16S rRNA gene fragments of the acetate-utilizing syntrophic component of the binary culture was performed; it was found to cluster with clones of uncultured gram-positive bacteria within the family Syntrophomonadaceae. The acetate-oxidizing bacterium is thus the first representative of this cluster obtained in a laboratory culture. Based on its phylogenetic position, the new acetate-oxidizing syntrophic bacterium is proposed to be assigned, in a Candidate status, to a new genus and species: "Candidatus Contubernalis alkalaceticum."


Subject(s)
Acetates/metabolism , Deltaproteobacteria/metabolism , Gram-Positive Bacteria/metabolism , Water Microbiology , 1-Propanol/metabolism , 2-Propanol/metabolism , Anaerobiosis , Butyrates/metabolism , Coculture Techniques , Ethanol/metabolism , Fructose/metabolism , Geologic Sediments/microbiology , Gram-Positive Bacteria/classification , Gram-Positive Bacteria/genetics , Gram-Positive Bacteria/ultrastructure , Isobutyrates , Oxidation-Reduction , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Serine/metabolism , Siberia , Species Specificity , Spores, Bacterial/ultrastructure
11.
Mikrobiologiia ; 73(3): 326-34, 2004.
Article in Russian | MEDLINE | ID: mdl-15315225

ABSTRACT

We isolated eight strains of denitrifying bacteria that reduce nitrate and nitrous oxide at pH 10 from Lake Magadi (Kenya). Despite certain differences between the strains, they are similar in terms of G+C content (66.1-68.1 mol %) and DNA-DNA homology (75-92%) and represent different morphotypes of the same species. Based on the results of partial 16S rRNA sequencing, strain Z-7398-2 was most closely related to the Halomonas campisalis isolate from Alkali Lake (USA). The DNA-DNA homology level between the tested strain and the type strain of H. campisalis 4A was 88%. These two strains were also similar phenotypically. However, the culture isolated by us was characterized by peculiar properties, such as obligate alkaliphily, which manifested itself in the culture dependence on carbonates and lack of growth at pH values below 7, a nitrous oxide-reducing capacity, and an unusual nitrate reductase that lacked molybdenum and a Mo cofactor.


Subject(s)
Alkalies/metabolism , Halomonas/enzymology , Nitrate Reductases/metabolism , Nitrous Oxide/metabolism , Oxidoreductases/metabolism , Water Microbiology , Carbonates , Coenzymes/analysis , Halomonas/genetics , Halomonas/growth & development , Hydrogen-Ion Concentration , Kenya , Molecular Sequence Data , Molybdenum/analysis , Nitrate Reductase , Oxidation-Reduction , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Sequence Homology, Nucleic Acid
12.
Mikrobiologiia ; 70(1): 77-85, 2001.
Article in Russian | MEDLINE | ID: mdl-11338841

ABSTRACT

A new alkaliphilic and moderately halophilic chemoorganotrophic anaerobic bacterium (strain Z-7986), which is spore-forming, rod-shaped, and has a gram-negative cell wall pattern, was isolated from the coastal lagoon mud of the highly mineralized Lake Magadi (Kenya). The organism is an obligatorily carbonate- and sodium chloride-dependent. It is a motile peritrichously flagellated rod that has developed within 3-17% NaCl concentration (with an optimum at 7-12% NaCl) and within a pH range of 7.7-10.3 (with an optimum at pH values of 8-8.5). It is a moderate thermophile with a broad temperature optimum from 36-55 degrees C and a growth maximum at 60 degrees C. The bacterium catabolizes glucose, fructose, sucrose, maltose, starch, glycogen, N-acetyl-D-glucosamine, and, to a slight degree, peptone and yeast extract. Its anabolism requires yeast extract or casamino acids. Glucose fermentation yields formate, acetate, ethanol, H2, and CO2. The bacterium is sulfidetolerant and capable of the nonspecific reduction of S0 to H2S. The G + C content of the DNA is 34.4 mol %. The analysis of the 16S rRNA sequence revealed that strain Z-7986 belongs to the order Haloanaerobiales and represents a new genus in the family Halobacteroidaceae. We suggest calling the organism Halonatronum saccharophilum gen. nov. sp. nov. The type strain of this species is Z-7986T (= DSM13868, = Uniqem 211).


Subject(s)
Bacillus/isolation & purification , Water Microbiology , Bacillus/classification , Bacillus/genetics , Bacillus/ultrastructure , Fermentation , Fresh Water , Hydrogen-Ion Concentration , Microscopy, Electron , Phylogeny , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics , Temperature
13.
Mikrobiologiia ; 70(6): 825-37, 2001.
Article in Russian | MEDLINE | ID: mdl-11785140

ABSTRACT

New alkaliphilic, saccharolytic, rod-shaped, gram-positive bacteria resistant to heating and drying and phylogenetically affiliated to the Bacillus lineage were isolated under strictly anaerobic conditions from sediments of the alkaline and highly mineralized Lake Magadi. Strain Z-7792 forms endospores; in strain Z-7984, endospore formation was not revealed. The strains are capable of both anaerobic growth (at the expense of fermentation of glucose and certain mono- and disaccharides with the formation of formate, ethanol, and acetate) and aerobic growth. Among polysaccharides, the strains hydrolyze starch, glycogen, and xylan. Yeast extract or methionine are required for growth. The strains are strict alkaliphiles exhibiting obligate requirement for Na+ and carbonate ions but not for Cl- ion. Growth occurs at a total mineralization as high as 3.3-3.6 M Na+, with an optimum at 1-1.7 M Na+. Strain Z-7792 is an obligate alkaliphile with a pH growth range of 8.5-11.5 and an optimum of 9.5-9.7. Strain Z-7984 grows in a pH range of 7.0-10.5 with an optimum at 8.0-9.5. Both strains are mesophiles having a growth optimum at 37-38 degrees C. They belong to bacilli with a low G + C content. The G + C contents of the DNA of strains Z-7792 and Z-7984 are 39.2 and 41.5 mol%, respectively. These isolates of facultatively anaerobic, strictly alkaliphilic, Na(+)-dependent bacilli can be considered representatives of the ecological group adapted to the life at drying-up shoars of soda lakes. Because of their independence of NaCl and lack of obligate dependence on sodium carbonates, the isolates are to be assigned to athalassophilic organisms. According to their physiological and phylogenetic characteristics, they taxonomically belong to group 1 of the species of bacilli, occupying a position intermediate between the genera Amphibacillus and Gracilibacillus. The isolates are described as new species of Amphibacillus: A. fermentum (type strain, Z-7984T) and A. tropicus (type strain, Z-7792T).


Subject(s)
Bacillus/classification , Bacillus/genetics , Bacillus/growth & development , Bacillus/ultrastructure , Carbohydrate Metabolism , DNA, Bacterial/analysis , Kenya , Phylogeny
14.
Int J Syst Evol Microbiol ; 50 Pt 3: 1287-1295, 2000 May.
Article in English | MEDLINE | ID: mdl-10843074

ABSTRACT

A moderately thermophilic, organotrophic bacterium with vibrioid cells was isolated from a sample of a cyanobacterial mat from caldera Uzon, Kamchatka, Russia, and designated strain Z-9701T. Cells of strain Z-9701T were curved, Gram-negative rods, 0.5-0.7 x 2.5-5.0 microm in size, with tapering ends and with fast, wavy movement by means of lateral flagella located on the concave side of the cell. Colonies were small, white, irregular or round, 0.2 mm in diameter, and with even edges. Strain Z-9701T was an obligate anaerobe with a temperature optimum at 60-65 degrees C and a pH optimum at 7.3. It fermented glucose, fructose, mannose, N-acetyl-D-glucosamine, adonite, arginine, serine, peptone, yeast extract and Casamino acids. The fermentation products formed during growth on glucose were acetate, lactate, H2, CO2 and ethanol. Strain Z-9701T reduced elemental sulfur to H2S during organotrophic growth with glucose or peptides as energy and carbon sources. In the presence of S0, strain Z-9701T was capable of lithotrophic growth with molecular hydrogen as energy substrate and 0.1 g yeast extract l(-1) as carbon source. Sulfate, thiosulfate, nitrate, Fe(III) and sulfite were not reduced and did not stimulate growth. The G+C content of strain Z-9701T DNA was 54.6 mol%. The results of 16S rDNA sequence analyses revealed that strain Z-9701T belongs to the cluster within the Clostridium group formed by Thermanaerovibrio acidaminovorans, Dethiosulfovibrio peptidovorans, Anaerobaculum thermoterrenum and Aminobacterium colombiense, but the level of sequence similarity with the members of this cluster was not very high (87.6-92.2%). Among these organisms, Thermanaerovibrio acidaminovorans is phenotypically close to strain Z-9701T. However, the two organisms showed a relatively low level of similarity of their 16S rRNA sequences (92.2%) and of DNA-DNA hybridization (15 +/- 1%). Nevertheless, on the basis of the similar morphology and physiology of the new isolate and Thermanaerovibrio acidaminovorans, strain Z-9701T was placed in the genus Thermanaerovibrio and a new species, Thermanaerovibrio velox, proposed for it. The type strain is Z-9701T (= DSM 12556T).


Subject(s)
Fresh Water/microbiology , Gram-Negative Anaerobic Bacteria/classification , Sulfur-Reducing Bacteria/classification , Sulfur/metabolism , Culture Media , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Gram-Negative Anaerobic Bacteria/metabolism , Gram-Negative Anaerobic Bacteria/ultrastructure , Lactates/metabolism , Molecular Sequence Data , Oxidation-Reduction , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Sulfur-Reducing Bacteria/metabolism , Sulfur-Reducing Bacteria/ultrastructure , Temperature
15.
Curr Microbiol ; 37(3): 177-85, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9688817

ABSTRACT

Two strains, asporogenous Z-7940 and sporogenous Z-7939, of a moderately haloalkaliphilic, obligately anaerobic, fermentative bacteria, motile, with Gram-positive cell wall structure, were isolated from soda deposits in Lake Magadi, Kenya. Both strains are mesophilic and utilize only two amino acids, histidine and glutamate, with formation of acetate and ammonium as the main end products. Strain Z-7939 in addition is able to utilize pyruvate. DNA-DNA homology between strains Z-7940 and Z-7939 was 94%, indicating that in spite of phenotypic differences they belong to the same species. They are true alkaliphiles with a pH range for growth of the type strain Z-7940 from pH 8.0 to pH 10.5, optimum at pH 9.4. Both strains obligately depend on sodium and bicarbonate ions. The optimum salt concentration for growth of the type strain is 8-10% wt/vol and the range from 4% to 16%. The G+C content of strain Z-7940 is 31.9 mol% and the strain Z-7939 is 32.3 mol%. Analysis of 16S rDNA sequence of the type strain shows it to belong to cluster XI of the low G+C Gram-positive bacteria. On the basis of its distinct phylogenetic position and physiological properties, we propose a new genus and new species Natronoincola histidinovorans for these strains. The type strain is Z-7940 (=DSM 11416).


Subject(s)
Bacteria, Anaerobic/isolation & purification , Gram-Positive Asporogenous Rods/isolation & purification , Bacteria, Anaerobic/classification , Bacteria, Anaerobic/cytology , Bacteria, Anaerobic/genetics , Bacteria, Anaerobic/physiology , Bicarbonates/administration & dosage , Genome, Bacterial , Glutamates/metabolism , Gram-Positive Asporogenous Rods/cytology , Gram-Positive Asporogenous Rods/genetics , Gram-Positive Asporogenous Rods/physiology , Histidine/metabolism , Hydrogen-Ion Concentration , Phenotype , Pyruvic Acid/metabolism , Sequence Analysis, RNA , Sodium/administration & dosage
16.
Curr Microbiol ; 37(2): 94-100, 1998 Aug.
Article in English | MEDLINE | ID: mdl-9662608

ABSTRACT

Strain Z-7934, an alkaliphilic, obligately anaerobic, fermentative, asporogenous bacterium with Gram-positive cell wall structure, was isolated from soda deposits in Lake Magadi, Kenya. The organism ferments only a few amino acids, preferentially arginine and ornithine, with production of acetate, propionate, and ammonia. It is a true alkaliphile, with pH range for growth ranging from 7.5 to 10.5 (optimum pH 8.5), and growth is dependent on the presence of sodium ions. The G+C content of the genomic DNA is 37.6 mol%. 16S rDNA sequence analysis of strain Z-7934 shows that it belongs phylogenetically to cluster XI of the low G+C Gram-positive bacteria. On the basis of its distinct phylogenetic position and unique physiological properties, we propose a new genus and new species, Tindallia magadii, for this strain. The type strain is Z-7934(T) (=DSM 10318).


Subject(s)
Alkalies/metabolism , Ammonia/metabolism , Bacteria, Anaerobic/classification , Fresh Water/microbiology , Water Microbiology , Bacteria, Anaerobic/cytology , Bacteria, Anaerobic/genetics , Cell Division/physiology , DNA, Ribosomal/genetics , Microscopy , Microscopy, Electron , Molecular Sequence Data , Nucleic Acid Hybridization , Phylogeny , RNA, Bacterial/analysis , RNA, Bacterial/genetics , RNA, Ribosomal, 16S/genetics
17.
Int J Syst Bacteriol ; 47(1): 144-9, 1997 Jan.
Article in English | MEDLINE | ID: mdl-8995816

ABSTRACT

A new alkaliphilic, sulfate-reducing bacterium, strain Z-7935T (T = type strain), was isolated from a soda-depositing lake, Lake Magadi in Kenya. This organism is a motile vibrio which utilizes only hydrogen and formate as electron donors and sulfate, sulfite, and thiosulfate, but not sulfur, as electron acceptors. Thiosulfate is dismutated. Strain Z-7935T is an obligately sodium-dependent alkaliphile which grows in sodium carbonate medium and does not grow at pH 7; the maximum pH for growth is more than pH 10, and the optimum pH is 9.5 to 9.7. The optimum NaCl concentration for growth is 3% (wt/vol). The optimum temperature for growth is 37 degrees C. The G + C content of the DNA is 48.6 mol%. 16S ribosomal DNA sequence analysis revealed that strain Z-7935T represents a new lineage with genus status in the delta subclass of the Proteobacteria. The name Desulfonatronovibrio hydrogenovorans gen. nov., sp. nov. is proposed for this organism; the type strain of D. hydrogenovorans is strain Z-7935 (= DSM 9292).


Subject(s)
Desulfovibrio/classification , Bacteriological Techniques , Base Composition , Carbonates/metabolism , Culture Media/metabolism , Desulfovibrio/genetics , Desulfovibrio/growth & development , Desulfovibrio/metabolism , Formates/metabolism , Hydrogen/metabolism , Hydrogen-Ion Concentration , Lipids/analysis , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Homology, Nucleic Acid , Sodium Chloride/metabolism , Sulfates/metabolism , Sulfites/metabolism , Thiosulfates/metabolism
18.
Int J Syst Bacteriol ; 46(1): 305-12, 1996 Jan.
Article in English | MEDLINE | ID: mdl-8573509

ABSTRACT

During a study of microbial communities in athalassic bodies of water, three new species within the genus Spirochaeta were described. These are alkaliphilic Spirochaeta alkalica sp. nov. Z-7491 (DSM 8900) and halophilic S. africana sp. nov. Z-7692 (DSM 8902) from the soda-depositing Lake Magadi in Central Africa and haloalkaliphilic S. asiatica sp. nov. Z-7591 (DSM 8901) from Lake Khatyn, Central Asia. These mesophilic spirochetes develop at pHs of > 9 as anaerobic saccharolytic dissipotrophs. The DNA base compositions (moles percent G+C) of the strains were as follows: S. alkalica Z-7491, 57.1; S. africana Z-7692, 56.1; and S. asiatica Z-7591, 49.2. The optimum growth parameters (temperature, pH, and NaCl concentration [percent, wt/vol], respectively) were as follows: for S. alkalica Z-7491, 35 degrees C, 9.2, and 5 to 7%; for S. africana Z-7692, 35 degrees C, 9.3, and 5 to 7%; and for S. asiatica Z-7591, 35 degrees C, 8.9, and 3 to 6%. The products of glucose fermentation were acetate, hydrogen, ethanol, and lactate, in different proportions, for S. alkalica and S. africana; for S. asiatica, they were acetate, ethanol, and lactate. S. asiatica is strictly anaerobic, while S. alkalica and S. africana are rather aerotolerant. All three species group within the radiation of the majority of the species of the genus Spirochaeta. Studies of the genes encoding 16S rRNA indicate a possible fanning out of the phylogenetic tree of spirochetes.


Subject(s)
Spirochaeta/classification , Africa, Eastern , Asia, Central , Bacteria, Anaerobic/classification , Bacteria, Anaerobic/isolation & purification , Bacteria, Anaerobic/ultrastructure , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Molecular Sequence Data , Phylogeny , RNA, Ribosomal, 16S/genetics , Spirochaeta/isolation & purification , Spirochaeta/ultrastructure , Water Microbiology
20.
FEBS Lett ; 300(2): 193-6, 1992 Mar 30.
Article in English | MEDLINE | ID: mdl-1532942

ABSTRACT

Cells of Methanohalophilus halophilus swelled when exposed to hypotonic solutions of NaCl at pH 7.0. The swelling of the cells ceased in the presence of Mg2+. Methane formation by non-growing cells was strongly dependent on the NaCl concentration. Among other monovalent and divalent cations only Li+ and Mg2+ could partly substitute for a specific function of sodium ions. The artificial Na+/H+ antiporter, monensin, exerted a strong inhibitory effect on methane formation from methylamine. The membrane-bound Mg(2+)-stimulated ATPase of these cells was enhanced at low (40 mM) NaCl concentration while higher concentrations of this solute were inhibitory. The results obtained show that sodium ions are a prerequisite for optimal methane formation and ATPase activity in these cells. However, both of these processes required different sodium ion concentrations.


Subject(s)
Adenosine Triphosphatases/metabolism , Euryarchaeota/metabolism , Methane/metabolism , Sodium/metabolism , Methylamines/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...