Deoxyribonucleic acid relatedness among strains of the moderately halophilic speciesDeleya halophila

The genomic relatedness among 16 strains assigned to the moderately halophilic speciesDeleya halophila and other 20 representative strains of halophilic and nonhalophilic species was estimated by determination of deoxyribonucleic acid (DNA) base composition and by DNA-DNA hybridization studies. The guanine-plus-cytosine (G + C) base contents, determined from the melting temperature of DNAs ofD. halophila strains, were 66.0–68.8 mol %. DNA-DNA homology studies, determined by membrane filter technique, indicate that the 16 strains ofD. halophila comprise a genetically homogeneous group. High homology (70–100%) was obtained between the type strainD. halophila CCM 3662 and the otherD. halophila strains studied; however, very low DNA relatedness was found between the representative strains ofD. halophila and otherDeleya species (13-0%), as well as other moderately halophilic, marine, or nonhalophilic bacteria investigated.     

Propionigenium modestum gen. nov. sp. nov. a new strictly anaerobic,nonsporing bacterium growing on succinate

From marine and freshwater mud samples and from human saliva new strictly anaerobic, Gram-negative, nonsporeforming bacteria were isolated growing with succinate as sole source of carbon and energy. All strains grew in defined mineral media containing at least 1% sodium chloride. Succinate was stoichiometrically transformed to propionate und carbon dioxide; the growth yield varied between 2.1 and 2.4 g cell dry weight per mol of succinate fermented. In addition to succinate, only fumarate, l-aspartate, l-malate, oxaloacetate and pyruvate, were utilized and were stoichiometrically fermented to propionate and acetate. Yeast extract was not fermented but enhanced growth rates and yields. Neither sulfate, sulfur, nor nitrate were reduced. The DNA base ratio was 33.9±0.3 mol % guanine plus cytosine. A marine isolate, strain Gra Succ 2, is described as type strain of a new species, Propionigenium modestum gen. nov. sp. nov., in the family Bacteroidaceae.     

Deoxyribonucleic acid base composition of simonsiellaceae

The molar percentages of guanine plus cytosine in the DNA of 51 strains of Simonsiellaceae were determined by buoyant density ultracentrifugation of cell lysates in CsCl. The DNA base ratios ranged from 41–55 mole-% guanine plus cytosine. These values fall within the range known for the Order Cytophagales, the non-fruiting gliding bacteria, and are out-side the range of the Order Myxobacterales, the fruiting myxobacteria. Among the strains of the genus Simonsiella, four distinct groups can be delineated on the basis of source of origin (sheep, dog, cat, human) and GC content. The neotype of Alysiella filiformis has a GC content of 45.4 mole-%.     

Physiological and biochemical contributions to the taxonomy of the genus Prototheca

16 strains of the genus Prototheca do not produce extracellular amylolytic enzymes. The base composition of their DNA shows rather continuous values from 62% to 78% GC (guanine + cytosine). Their assignment to four species and their possible relationship with Chlorella protothecoides are discussed.Abbreviations Used GC guanine + cytosine - SSC saline sodium citrate     

Methanogenium,a new genus of marine methanogenic bacteria,and characterization ofMethanogenium cariaci sp. nov. andMethanogenium marisnigri sp. nov.

A new genus of marine methanogenic bacteria and two species within this genus are described.Methanogenium is the proposed genus andMethanogenium cariaci the type species. Cells of the type species are Gram-negative, peritrichously flagellated, irregular cocci with a periodic wall surface pattern. Colonies formed by these bacteria are yellow, circular and umbonate with entire edges. The DNA base composition is 52 mol% guanine plus cytosine. Formate or hydrogen and carbon dioxide serve as substrates for growth. Cells ofMethanogenium marisnigri are of similar shape but smaller diameter thanM. cariaci. The colonies ofM. marisnigri are convex, and the DNA base composition is 61 mol % G+C. Formate or hydrogen and carbon dioxide are growth substrates. Sodium chloride is required for growth of both methanogens.Abbreviations SDS sodium dodecylsulfate - PIPES piperazine-N,N-bis (2 ethanesulfonic acid) - HS-CoM coenzyme M, 2-mercaptoethanesulfonic acid     

Fermentation of 2-methoxyethanol by Acetobacterium malicum sp. nov. and Pelobacter venetianus

Anaerobic bacteria degrading 2-methoxyethanol were enriched from freshwater sediments, and three strains were isolated in pure culture. Two of them were Grampositive non-spore-forming rods and grew strictly anaerobically by acetogenic fermentation. Optimal growth occurred at 30°C, initial pH 7.5–8.0. 2-Methoxyethanol and 2-ethoxyethanol were fermented to acetate and corresponding alcohols. Hydrogen plus carbon dioxide, formate, acetoin, l-malate, lactate, pyruvate, fructose, and methoxyl groups of 3,4,5-trimethoxybenzoate and 3,4,5-trimethoxycinnamate were fermented to acetate. 1,2-Propanediol was fermented to acetate, propionate, and propanol. Strain MuME1 was described as a new species, Actetobacterium malicum. It had a DNA base composition of 44.1 mol% guanine plus cytosine. The third strain, which was identified as Pelobacter venetianus, fermented 2-methoxyethanol to methanol, ethanol, and acetate.     

Fermentation of trihydroxybenzenes by Pelobacter acidigallici gen. nov. sp. nov., a new strictly anaerobic,non-sporeforming bacterium

Five strains of rod-shaped, Gram-negative, non-sporing, strictly anaerobic bacteria were isolated from limnic and marine mud samples with gallic acid or phloroglucinol as sole substrate. All strains grew in defined mineral media without any growth factors; marine isolates required salt concentrations higher than 1% for growth, two freshwater strains only thrived in freshwater medium. Gallic acid, pyrogallol, 2,4,6-trihydroxybenzoic acid, and phloroglucinol were the only substrates utilized and were fermented stoichiometrically to 3 mol acetate (and 1 mol CO₂) per mol with a growth yield of 10g cell dry weight per mol of substrate. Neither sulfate, sulfur, nor nitrate were reduced. The DNA base ratio was 51.8% guanine plus cytosine. A marine isolate, Ma Gal 2, is described as type strain of a new genus and species, Pelobacter acidigallici gen. nov. sp. nov., in the family Bacteroidaceae. In coculture with Acetobacterium woodii, the new isolates converted also syringic acid completely to acetate. Cocultures with Methanosarcina barkeri converted the respective substrates completely to methane and carbon dioxide.     

Isolation and Characterization of a Novel Thermophilic, Freshwater Methanogen

A novel thermophilic, coccoid methanogen isolated from nonthermal freshwater sediments is described. Hydrogen plus carbon dioxide and formate were substrates for methanogenesis, and methane production was stimulated by yeast extract, Casamino Acids, and tryptose. Growth also occurred autotrophically. Elevated levels of sodium chloride were not required for maximum growth and were inhibitory above 2%. The minimum doubling time occurred at 57°C, and the upper and lower limits for methane production were 62 and 26°C, respectively. The optimum pH for growth was between 7.0 and 7.5. Inhibitory antibiotics included metronidazole, anisomycin, chloramphenicol, and lasalocid. Colonies were circular, dark yellow, shiny, and convex with entire edges. Cells were 1 to 2.5 μm in diameter, nonmotile, occurring singly or in pairs, and fimbriated. Cells were lysed by pronase or trypsin digestion, glass-distilled water, and 1% sodium dodecyl sulfate. Electron micrographs of thin sections showed a monolayered cell wall ca. 20 nm thick. The DNA base ratio was 49.2 mol% guanine plus cytosine. The whole cell protein pattern differed from that of other named coccoid methanogens.     

Base composition of DNA from symbiotic dinoflagellates: a tool for phylogenetic classification

DNA of eight endosymbiotic dinoflagellates (zooxanthellae) from seven different host species has been analyzed as to its thermal characteristics and base composition by means of spectrophotometry and high performance liquid chromatography. All algae under investigation contain both methylcytosine and hydroxymethyluracil in addition to the bases typical of nuclear DNA. As a result, melting temperatures are decreased, suggesting lower contents of guanine plus cytosine than actually present. True percentages of guanine plus cytosine plus methylcytosine range from about 43 to 54 mol%. They are unique for the symbionts from different hosts, indicating phylogenetic separation of the taxa comparised within the genus Symbiodinium.Abbreviations dA deoxyadenosine - dC deoxycytidine - dG deoxyguanosine - dT deoxythymidine - m5dC 5-methyldeoxycytidine - hmdU 5-hydroxymethyldeoxyuridine - rC ribocytidine - Br8G bromine-80guanosine - A adenine - C cytosine - G guanine - T thymine - m5C 5-methylcytosine - hmU 5-hydroxymethyluracil - G+C guanine plus cytosine plus 5-methylcytosine - HPLC high performance liquid chromatography - T _m temperature at the midpoint of hyperchromic shift - CTAB N-cetyl-N,N,N-trimethyl-ammonium bromide - EDTA ethylenediamine-tetraacetic acid, disodium salt - TRIS tris-(hydroxymethyl)-aminomethane - 1×SSC standard saline citrate (0.15 M NaCl+0.015 M trisodium citrate, pH 7.0)     

Deoxyribonucleic acid base compositions of hyphomicrobia

Summary The deoxyribonucleic acids of 70 hyphomicrobia were examined at equilibrium in neutral CsCl density gradients. The guanine plus cytosine (%G+C) content was estimated to range from 59.2 to 66.8% G+C. The strains could be divided into three groups with different base composition of their DNA; 61.0±1.1%, 64.1±0.6%, and 66.5±0.6% G+C. The values are compared with those for the base composition of DNA of a number of phototrophic, budding bacteria.     

Marine acidophilic sulfur-oxidizing bacterium requiring salts for the oxidation of reduced inorganic sulfur compounds

An acidophilic sulfur-oxidizing bacterium was isolated from seawater, and designated as strain SH. Strain SH was a Gram-negative, rod-shaped and motile bacterium, which had an optimum temperature and pH value for growth of 30 degrees C and 4.0, respectively. The mol% guanine plus cytosine of the DNA was 46.0. Chemolithotrophic growth was observed with elemental sulfur and tetrathionate at pH 4.0, and was not observed with ferrous ion. The isolate was able to utilize carbon dioxide as a carbon source, and was unable to grow heterotrophically with yeast extract or glucose. The growth of strain SH was activated in medium supplemented with NaCl. However, LiCl and KCl did not sustain the growth of strain SH. The results indicate that strain SH was an acidophilic, halophilic, and obligately chemolithotrophic sulfur-oxidizing bacterium. Phylogenetic analysis based on 16S rDNA sequences indicated that strain SH had a close relationship to Acidithiobacillus thiooxidans. The oxidizing activities of sulfur and sulfite with resting cells were stimulated not only by the addition of NaCl, but also by KCl and LiCl. The oxidation of sulfite was inhibited by ionophores, carbonyl cyanide- m-chlorophenylhydrazone (CCCP), and monensin, and respiratory inhibitors, KCN and 2-heptyl-4-hydroxy-quinoline-N-oxode (HQNO).     

Isolation and Characterization of a Halophilic Methanogen from Great Salt Lake

A halophilic methanogenic microorganism isolated from sediments collected from the southern arm of Great Salt Lake, Utah, is described. Cells were irregular, nonmotile cocci approximately 1.0 μm in diameter and stained gram negative. Colonies from anaerobic plates and roll tubes were foamy, circular, and cream-yellow. Methanol, methylamine, dimethylamine, and trimethylamine supported growth and methanogenesis. Hydrogen-carbon dioxide, formate, and acetate were not utilized. Sodium and magnesium were required for growth; the optimum NaCl concentration ranged between 1.0 and 2.0 M, with the minimum doubling time occurring at 2.0 M. The optimum growth temperature was 35°C, with maximum growth rate occurring at pH 7.5. The DNA base composition was 48.5 mol% guanine + cytosine. SLP is the type strain designation (= ATCC 35705).     

Mixotrophic Growth of a Thiobacillus ferrooxidans Strain

Mixotrophic growth of a Thiobacillus ferrooxidans strain is described. DNA moles percent guanine plus cytosine and homology determinations confirmed that the mixotrophically grown T. ferrooxidans cultures were not contaminated with heterotrophic Acidiphilium strains.     

Deoxyribonucleic Acid Base Composition of Stentor coeruleus*

SYNOPSIS. The deoxyribonucleic acid of Stentor coeruleus has of 33 moles percent guanine plus cytosine. a buoyant density in CsCl of 1.692 gcm^?3 and a base composition of 33 moles percent guanine plus cytosine.     

Deoxyribonucleic Acid Hybridization Studies on Flavobacterium meningosepticum

Seventeen flavobacteria, including 12 strains of Flavobacterium meningosepticum, were investigated to determine their genetic relationships by deoxyribonucleic acid (DNA)-DNA hybridization and guanine plus cytosine content. The percentage of binding among the strains tested ranged from 6 to 87%. There was no correlation between the serotype and DNA-duplex formation. The guanine plux cytosine content of the representative strains of the five serotypes ranged from 31 to 50%.     

Use of Shake Cultures in a Semisolid Thioglycolate Medium for Differentiating Staphylococci from Micrococci

The standard diagnostic test for differentiating staphylococci from micrococci is based on the ability of the former to produce acid anaerobically in a glucose-containing growth medium. This test has been modified to provide greater convenience, easier interpretation of results, and better correlation with deoxyribonucleic acid (DNA) base composition. In the modified test, shake cultures in Brewer's fluid thioglycolate medium with 0.3% agar added are observed for growth in the anaerobic zone of the tubes. This test was applied to 125 strains of staphylococci and micrococci, and all except two strains gave results that were consistent with other criteria. Of particular interest were eight strains of Micrococcus saprophyticus and three strains of M. lactis that have a DNA composition of 30 to 37% guanine plus cytosine (GC). All 11 of these cultures produced anaerobic growth and thus would be classified as staphylococci. Strains of M. lactis that have a high GC content in their DNA grew only aerobically. Some cultures of staphylococci produced characteristic band patterns of anaerobic growth and other cultures produced only a few anaerobic colonies from an inoculum of 10(6) to 10(7) cells. These observations suggest some interesting genetic and metabolic capabilities in such cultures.     

DNA base composition of extremely halophilic cocci

Summary The percentage guanine+cytosine (GC) content of the DNA of 9 extremely halophilic cocci were determined from melting temperature (T _m) and the E ₂₆₀/E ₂₈₀ ratio at pH 3. The values found ranged from 60.5–65.8, with an average 62.6% GC.     

Reisolation of Staphylococcus salivarius from the human oral cavity

Twenty-four strains of gram-positive facultative cocci, arranged primarily in small clusters, were isolated from the surface of the human tongue. With the exception of 14 catalase-negative isolates, these strains were identical in cultural and biochemical characteristics and in deoxyribonucleic acid base composition. All cultures produced viscous growth in both liquid and agar media. They fermented glucose anaerobically, reduced nitrate beyond nitrite, were benzidine-positive, and failed to grow in the presence of 5% NaCl or at 45 C. In addition, they exhibited guanine plus cytosine (G + C) contents of 55.4 to 58.3%. These isolates differed from strains of pediococci, aerococci, and micrococci which were included for comparison. On the basis of G + C content, these organisms appear to be intermediate between micrococci and staphylococci; however, on the basis of anaerobic glucose fermentation, it is suggested that they be placed in the genus Staphylococcus. It is proposed that they be recognized as S. salivarius.     

Genetic relatedness of clinical and environmental isolates of lactose-positiveVibrio vulnificus

Environmental isolates of lactose-positiveVibrio vulnificus from different geographic areas were compared with clinical strains ofV. vulnificus on the basis of their phenotypic traits, virulence, DNA base composition, and DNA-DNA reasociation. EnvironmentalV. vulnificus strains were phenotypically indistinguishable from clinical isolates. These strains had a DNA base composition of 47–48 mol% guanine + cytosine and 85% reassociation at stringent temperature with DNA from clinicalV. vulnificus strains. These result indicateV. vulnificus strains from widely separated regions of the marine environment are indistinguishable from strains that have been agents of septicemia associated with shellfish consumption and of wound infections associated with seawater exposure.