Showing papers in "Archives of Microbiology in 1983"

Studies on dissimilatory sulfate-reducing bacteria that decompose fatty acids

Abstract: Gliding motility, ultrastructure and nutrition of two newly isolated filamentous sulfate-reducing bacteria, strains 5ac10 and 4be13, were investigated. The filaments were always attached to surfaces. Growth was supported by addition of insoluble aluminium phosphate or agar as substrata for gliding movement. Electron microscopy of ultrathin sections revealed cell walls characteristic of Gramnegative bacteria; the undulated structure of the outer membrane may pertain to the translocation mechanism. Intracytoplasmic membranes were present. Acetate, higher fatty acids, succinate or fumarate served as electron donors and carbon sources. Strain 5ac10 grew also with lactate, but not with benzoate that was used only by strain 4be13. Strain 5ac10 was able to grow slowly on H2 plus CO2 or formate in the presence of sulfate without additional organic carbon source. The capacity of complete oxidation was shown by stoichiometric measurements with acetate plus sulfate. Both strains contained b- and c-type cytochromes. Desulfoviridin was detected only in strain 5ac10. The two filamentous gliding sulfate reducers are described as new species of a new genus, Desulfonema limicola and Desulfonema magnum.

Methanococcus jannaschii sp. nov., an extremely thermophilic methanogen from a submarine hydrothermal vent

Abstract: A new extremely thermophilic methane-producing bacterium was isolated from a submarine hydrothermal vent sample collected by a research team from the Woods Hole Oceanographic Institution using the manned submersible ALVIN. The sample was obtained from the base of a “white smoker” chimney on the East Pacific Rise at 20° 50′ N latitude and 109° 06′ W longitude at a depth of 2600 m. The isolate was a motile irregular coccus with an osmotically fragile cell wall and a complex flagellar system. In defined medium with 80% H2 and 20% CO2, the isolate had a doubling time of 26 min at 85° C. The pH range for growth was 5.2 to 7.0 with an optimum near 6.0. NaCl was required for growth with an optimum of 2 to 3% (w/v). The mol % G+C was 31%. In cell-free extracts, methane formation from methylcoenzyme M was temperature-dependent, and H2 or formate served as electron donors. Methane formation from H2 and CO2 occurred at a much lower rate. Oligonucleotide cataloging of the 16S ribosomal RNA established the isolate as a new species of the genus Methanococcus and the name Methanococcus jannaschii is proposed. The isolation of M. jannaschii from a submarine hydrothermal vent provides additional evidence for biogenic production of CH4 from these deep-sea environments.

RNA polymerase from Rhizobium japonicum

Abstract: DNA-dependend RNA polymerase (EC 2.7.7.6) from Rhizobium japonicum was purified. The subunit structure was found to be ββ′α2σ, with the following apparent molecular weights determined by electrophoresis: Mr (β and β') 150,000 each, Mr (σ) 96,000, Mr (α) 40,000, Mr (holoenzyme) 490,000, Mr (core enzyme) 380,000. The recovery of σ was 28%. RNA polymerase from aerobically grown R. japonicum cells and from nitrogen-fixing cells have the same electrophoretic properties suggesting that no chemical modification of the enzyme occurs when cells undergo this metabolic differentiation.

Heliobacterium chlorum, an anoxygenic brownish-green photosynthetic bacterium containing a “new” form of bacteriochlorophyll

Abstract: Heliobacterium chlorum is a brownish-green anoxygenic photosynthetic bacterium, isolated from surface soil It fixes N2 readily, and contains a hitherto unknown form of bacteriochlorophyll (Bchl) The latter, designated as BchlgGg, shows a major absorbancy peak in vivo at 788 nm As yet, the subcellular localization of the photosynthetic pigment is uncertain; neither chlorosomes nor extensively developed intracytoplasmic membranes of the kind produced by most photosynthetic bacteria are observed in electron micrographs of thin sections H chlorum grows rapidly as a mesophilic photoheterotroph, requires biotin as an essential growth factor, and appears to move by gliding motility The bacterium is unable to grow aerobically in darkness, and photosynthetic growth is severely inhibited by molecular oxygen The extreme O2-sensitivity of H chlorum may be related to its low content of (neurosporene-like) carotenoid

Characterization of Methanococcus maripaludis sp. nov., a new methanogen isolated from salt marsh sediment

Abstract: A predominant methanogenic bacterium was isolated from salt-marsh sediment near Pawley's Island, South Carolina. A habitat-simulating medium with H2:CO2 as substrate was used for enrichment and isolation. The methanogen is strictly anaerobic, weakly-motile, non-sporeforming, Gram negative, and a pleomorphic coccoid-rod averaging 1.2 by 1.6 μm. Colonies are circular, translucent, pale yellow, and have a smooth surface and an entire edge. The organism is a mesophile, growing between 18 and 47°C, with an optimum near 38°C. The pH optimum for growth is 6.8–7.2, and only formate or a mixture of H2 plus CO2 serve as substrates. Seawater (20–70% v/v) is required, but it can be replaced by 15 mM, or greater, magnesium. Optimal growth occurs with 110 mM sodium. Growth rate is stimulated by selenium (10 μM) but organic compounds (acetate, vitamins, amino acids) are neither stimulatory nor required. The methanogen grows well in autotrophic medium with a doubling time of about 2h. Cells are fragile, are lysed by aqueous solutions of low osmolality and by detergents, and the lack muramic acid. The cell wall is a single electron dense layer. The DNA base composition is 33 mol % guanine plus cytosine. Antigenic relationship of cells and the 16S ribosomal RNA catalog indicate that the salt marsh methanogen is a unique species of Methanococcus, for which we propose the name Methanococcus maripaludis sp. nov.

Degradation and Turnover of Peroxisomes in the Yeast Hansenula polymorpha Induced by Selective Inactivation of Peroxisomal Enzymes

Abstract: Inactivation of peroxisomal enzymes in the yeast Hansenula polymorpha was studied following transfer of cells into cultivation media in which their activity was no longer required for growth. After transfer of methanol-grown cells into media containing glucose - a substrate that fully represses alcohol oxidase synthesis - the rapid inactivation of alcohol oxidase and catalase was paralleled by a disappearance of alcohol oxidase and catalase protein. The rate and extent of this inactivation was dependent upon conditions of cultivation of cells prior to their transfer. This carbon catabolite inactivation of alcohol oxidase was paralleled by degradation of peroxisomes which occurred by means of an autophagic process that was initiated by the formation of a number of electron-dense membranes around the organelles to be degraded. Sequestration was confined to peroxisomes; other cell-components such as ribosomes were absent in the sequestered cell compartment. Also, cytochemically, hydrolytic enzymes could not be demonstrated in these autophagosomes. The vacuole played a major role in the subsequent peroxisomal breakdown since it provided the enzymes required for proteolysis. Two basically similar mechanisms were observed with respect to the administration of vacuolar enzymes into the sequestered cell compartment. The first mechanism involved incorporation of a small vacuolar vesicle into the sequestered cell compartment. The delimiting membrane of this vacuolar vesicle subsequently disrupted, thereby exposing the contents of the sequestered cell compartment to vacuolar hydrolases which then degraded the peroxisomal proteins. The second mechanism, observed in cells which already contained one or more autophagic vacuoles, included fusion of the delimiting membranes of an autophagosome with the membrane surrounding an autophagic vacuole which led to migration of the peroxisome inside the latter organelle. Peroxisomes of methanol-grown H. polymorpha were degraded individually. In one cell 2 or 3 peroxisomes might be subject to degradation at the same time, but they were never observed together in one autophagosome. However, fusions of autophagic vacuoles in one cell were frequently observed. After inhibition of the cell's energy-metabolism by cyanide ions or during anaerobic incubations the formation of autophagosomes was prevented and degradation was not observed.

Chemoautotrophic growth of a marine Beggiatoa in sulfide-gradient cultures

Abstract: A recently isolated strain of Beggiatoa, MS-81-6 (cf. alba), was tested for chemoautotrophic growth in semi-solid (0.2% agar) sulfide/oxygen gradient cultures. The organism grew in a horizontal layer, the distance from the air/medium interface depending on sulfide concentrations and changing with time. Optimal growth as a gradient organism was based on a preference for reduced oxygen concentrations and a limited sulfide tolerance in combination with gliding motility. In gradient cultures chemoautotrophic growth was demonstrated by the following criteria: (1) biomass yield (protein) increased with increasing sulfide concentration, and estimated molar growth yields agreed with those for other sulfide-grown chemoautotrophs; (2) approximately 90% of total cell carbon and protein carbon were fixed from carbon dioxide; (3) the CO2-fixing enzyme, ribulosebisphosphate carboxylase, was present in cell-free extracts at a level typical of chemoautotrophs; (4) acidification of the medium, apparently linked to utilization of internal So granules, accompanied the later phase of growth. The ability to grow on acetate in the absence of a source of reduced sulfur renders the organism facultatively chemoautotrophic.

Interference of aromatic sulfo groups in the microbial degradation of the azo dyes Orange I and Orange II

Abstract: Pseudomonas strains K22 and KF46 had previously been isolated from chemostat cultures that were adapted to growth on 1-(4′-carboxyphenylazo)-4-naphthol (carboxy-Orange I) and 1-(4′-carboxyphenylazo)-2-naphthol (carboxy-Orange II), respectively. They were tested for their ability to degrade the sulfonated analogs 1-(4′-sulfophenylazo)-4-naphthol (Orange I) and 1-(4′-sulfophenylazo)-4-naphthol (Orange I) and 1-(4′-sulfophenylazo)-2-naphthol (Orange II). The sulfonated dyes served as models for commercially used textile dyes, which are known to be recalcitrant in aerobic waste water treatment plants. Substitution of sulfo for carboxy groups led to disturbance of the degradative pathways. The enzymes initiating degradation, the Orange I azoreductase and the Orange II azoreductase, accepted both, carboxylated and sulfonated dyes. Experiments with specifically 14C-labelled dyes indicated that sulfanilic acid, one of the products of the initial fission of the dyes, was channeled into a dead-end pathway. In the case of Orange I degradation, reactive metabolites of sulfanilic acid, presumably catechols, coupled with aminonaphthol, the other product of the azoreductase reaction. Orange II was degraded by strain KF46 when another suitable carbon source (e.g. 4-hydroxybenzoate) was supplied. Most but not all of the internally generated sulfanilic acid was excreted and intermolecular coupling of aromatic metabolites was not observed. However, the presence of sulfanilic acid and/or its metabolities still interfered with the degradation of the aminonaphthol part of the dye molecule and complete mineralization was not achieved.

Methyltransferases involved in methanol conversion by Methanosarcina barkeri.

Abstract: 2-(Methylthio)ethanesulfonate (CH3S-CoM) is formed as an intermediate in methanogenesis from methanol by cell-free extracts of Methanosarcina barkeri. The enzyme system involved in the methyltransfer from methanol to 2-mercaptoethanesulfonate (HS-CoM) was resolved into two enzyme fractions. One enzyme (methanol: 5-hydroxybenzimidazolylcobamide methyltransferase) appears to be a cobalamin-containing protein, which is oxygen sensitive. The other enzyme (Co-methyl-5-hydroxybenzimidazolylcobamide: HS-CoM methyltransferase) was purified. It is insensitive to oxygen and it transfers also the methylgroup from Co-methyl-5,6-dimethylbenzimidazolylcobamide to HS-CoM.

Symbiosis of methanogenic bacteria and sapropelic protozoa

Abstract: Fluorescent bacteria were demonstrated to be abundantly spread as single cells throughout the cytoplasm of the giant amoeba Pelomyxa palustris, the sapropelic ciliate Metopus striatus and six other anaerobic protozoa examined. The endosymbionts of P. palustris and M. striatus were identified as methanogenic bacteria on the basis of the presence of the deazaflavin coenzyme F420 and the pterin compound F342. Moreover individuals of P. palustris produced methane over a long period of incubation. The number of methanogenic bacteria was above 1010 cells/ml protozoal cytoplasm. Two types of methanogenic bacteria together with unidentified thick bacteria were found in P. palustris. The physiological background of this endosymbiosis and its functioning in degradation processes in the anoxic environment are discussed.

Bacteriochlorophyll g. A new bacteriochlorophyll from Heliobacterium chlorum

Abstract: A new bacteriochlorophyll g has been isolated from Heliobacterium chlorum. Its visible absorption spectrum is different from those of all other known bacteriochlorophylls, and it is extremely sensitive to oxygen in the presence of light. A proposal for the structure of the new bacteriochlorophyll g is given on the basis of absorption, CD, and 1H-NMR spectra of the corresponding bacteriopheophytin g and two main transformation products of Bchl g.

Chemical composition and structure of cell wall teichoic acids of staphylococci

Abstract: The cell wall teichoic acid structures of 22 staphylococci including 13 type strains were determined. Most of the strains contain a poly(polyolphosphate) teichoic acid with glycerol and/or ribitol as polyol component. The polyolphosphate backbone is partially substituted with various combinations of sugars and/or amino sugars. Most of the substituents occur in a monomeric form but some strains also contain dimers of N-acetylglucosamine as substituents. Staphylococcus hyicus subsp. hyicus NCTC 10350 and S. sciuri DSM 20352 revealed rather complex cell wall teichoic acids. They consist of repeating sequences of phosphate-glycerol-phosphate-N-acetylglucosamine. The amino sugar component is present in this case as a monomer or an oligomer (n less than or equal to 3). Moreover, the glycerol residues are partially substituted with N-acetylglucosamine. The cell wall teichoic acid of S. auricularis is a poly(N-acetylglucosaminyl-phosphate) polymer similar to that found in S. caseolyticus ATCC29750. The cell wall teichoic acid structures for type strains of S. auricularis, S. capitis, S. cohnii, S. haemolyticus, S. hominis, S. hyicus subsp. hyicus, S. sciuri, S. xylosus and S. warneri were determined for the first time in detail. The structures of some of the previously described teichoic acids had to be revised (S. epidermidis, S. simulans, S. aureus phage type 187).

Isolation and characterization of a nicotinic acid-degrading sulfate-reducing bacterium, Desulfococcus niacini sp. nov.

Abstract: The strains NAV-1, NAV-2, NAV-3 of new nonsporing sulfate-reducing bacteria with spherical to oval motile cells were isolated with nicotinic acid as electron donor and carbon source. All strains were obtained from marine sediment samples. Growth occurred in defined anaerobic salt water media supplemented with biotin and thiamine as growth factors. Utilization of nicotinic acid depended on the addition of selenite (10-8–10-7 mol/l); requirement for molybdate was not detected. Further compounds utilized as electron donors and carbon sources were hydrogen plus carbon dioxide, formate, acetate, propionate, higher fatty acids up to 16 carbon atoms, alcohols, pyruvate, malate, fumarate, succinate, glutarate, glutamate and pimelate. On hydrogen plus carbon dioxide or on formate, slow growth was obtained without an additional organic carbon source. Growth on acetate or propionate as sole organic substrates was possible, however, it was extremely slow. Stoichiometric measurements revealed that nicotinic acid was completely oxidized to carbon dioxide and ammonia. The average growth yield was 38 g cell dry weight per mol of nicotinic acid used. 3-Phenylpropionate was oxidized to carbon dioxide and benzoate; benzoate could not be oxidized further. The strains were able to reduce sulfite or thiosulfate instead of sulfate. No growth on organic compounds was observed in the absence of an electron acceptor. In the cell membrane fraction, b-type cytochrome was identified; desulfoviridin was not detected. Cell-free extracts oxidized nicotinic acid, nicotinamide or pyrazine-2-carboxylic acid with methylviologen as electron acceptor. Strain NAV-1 is described as type strain of the new species Desulfococcus niacini.

On the redox control of synthesis of anaerobically induced enzymes in enterobacteriaceae

Abstract: Mutants of Escherichia coli were isolated in which transcription of the structural genes for hydrogenase (hyd) and for one of the components of formate dehydrogenase (fdh) (of the formate hydrogen-lyase complex) is coupled with that of the lacZ gene. They were — together with lac fusions of the nifH and nifL genes from Klebsiella — used to study regulation by redox control, of the expression of the respective structural genes. The following results were obtained: (i) β-galactosidase synthesis was fully repressed in the presence of O2 or nitrate (anaerobically), and induced in the absence of an external electron acceptor. Fumarate as terminal electron acceptor only marginally affected nif expression and partially repressed hyd and fdh expression. Redox control of the synthesis of hydrogenase and formate dehydrogenase, therefore, (as well as that of nif) acts at the level of transcription; the size of the redox potential seems to be correlated with the amount of repression; (ii) β-galactosidase synthesis in the hyd:: lac and fdh::lac fusion strains is induced by formate. At high concentrations formate reverses the repression by nitrate and fumarate but not that by oxygen.

The rhizosphere microflora of wheat and barley with special reference to gram-negative bacteria

Abstract: Data on the dominant bacterial classes in the innermost rhizosphere of barley and wheat were collected. For this, ground root material was plated and the bacteria coming up as colonies were scored, mainly for metabolic functions. The results were used to classify the isolates, and produce linkage diagrams depicting the taxonomic relationships of them.

Distribution of plastocyanin and soluble plastidic cytochrome c in various classes of algae

Abstract: Several eukaryotic algae belonging to the main taxonomic classes have been cultured autotrophically in liquid medium supplemented with or depleted of copper to assay their ability to form plastocyanin or exchange it against plastidic cytochrome c-553. Most Chlorophyceae are able to substitute cytochrome c-533 for plastocyanin with some exceptions like Haematococcus or Dunaliella, which can only synthesize plastocyanin. Also within the Chlorella group, about half of the 28 strains assayed cannot synthesize cytochrome c-553 under copper deficiency. Species of Chrysophyceae, Xanthophyceae, and Rhodophyceae, on the other hand, cannot synthesize plastocyanin even when a comparatively high copper concentration (10μM) is available.

New facultative lithoautotrophic nitrite-oxidizing bacteria

Abstract: A nitrite-oxidizing bacterium was isolated from soil of the Old Botanic Garden in Hamburg and of a cornfield near Uxmal in Yucatan (Mexico). The cells are 0.5–0.8 ×1.2–2.0 μm in size, pleomorphic, mostly pear-shaped and motile by means of one subpolar to lateral flagellum. Intracytoplasmic membranes are present as caps of flattened vesicles or membrane vesicles in the central region of the cell. The organism grows best mixotrophically with a doubling time of 10 h to 18 h. The growth rate under heterotrophic conditions is slower than under mixotrophic conditions but higher than under lithoautotrophic conditions. The DNA G+C content of the DNAs of strain X14 and strain Y is 61.2 mol% and 61.6 mol%, respectively. Both strains share 100% DNA homology. Nitrobacter winogradskyi is moderately related only to the two isolates, showing an average DNA homology value of 36%. The phenotypic and genotypic differences from N. winogradskyi support evidence that more than one species of Nitrobacter exists. For Nitrobacter X14 and Nitrobacter Y the name N. hamburgensis is proposed.

Characterization of a homogenous preparation of carboxysomes from Thiobacillus neapolitanus

Abstract: A homogenous preparation of carboxysomes was isolated from Thiobacillus neapolitanus by means of density gradient centrifugation and preparative electrophoresis through agarose. Analysis of the carboxysomes by denaturing sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of 12–15 polypeptides. Approximately 62% of the total protein was found to consist of the large and small subunits of ribulose-1,5-bisphosphate carboxylase-oxygenase (RubisCO). Two polypeptides were found to be components of the carboxysome shell. Ribose-5-phosphate isomerase, ribulose-5-phosphate kinase, and fructose-1,6-bisphosphatase could not be detected in the carboxysome. Purified carboxysomal and cytoplasmic RubisCO were shown to be similar if not identical by several criteria including specific activity, carboxylase/oxygenase activity, and electrophoretic mobility.

Anaerobic acetate oxidation to CO2 by Desulfobacter postgatei. I: Demonstration of all enzymes required for the operation of the citric acid cycle

Abstract: Il est montre que toutes les enzymes exigees pour l'oxydation de l'acetate par la voie du cycle tricarboxylique sont presentes chez cette bacterie. Les enzymes des reactions anaplerotiques sont egelement decrites

Whole cell respiration and nitrogenase activities in Azotobacter vinelandii growing in oxygen controlled continuous culture

Abstract: Azotobacter vinelandii strain OP was grown in continuous culture at various dissolved oxygen concentrations of air (100% air saturation of the medium=225 ±14 μM O2). Sucrose was added as carbon source and either dinitrogen or ammonia as nitrogen sources. Irrespective of the nitrogen source steady state cultures showed the following general responses with dissolved oxygen concentrations increasing from about 1% to 30% air saturation: (i) cell protein levels, (ii) the amount of cell protein formed per sucrose consumed as well as (iii) nitrogenase activity decreased by at least a factor of two while (iv) cellular respiration increased. At higher oxygen concentrations the parameters changed only slightly, if at all. Increasing the sucrose concentration in the inflowing medium (s R) from 3 g/l to 15 g/l increased the total level of cellular respiration with nitrogen-fixing cultures but was more pronounced with ammonium-assimilating cultures. With nitrogen-fixing cultures cell protein levels increased five-fold while the ratio of protein formed per sucrose consumed as well as cellular nitrogenase activity remained unaffected. With ammonium-assimilating cultures the cell protein level was only doubled and the level of cell protein formed per sucrose consumed was decreased at the higher s R. Increasing the dilution rate at a constant oxygen concentration of 45% air saturation resulted in an almost parallel increase of both cellular respiratory and nitrogenase activity at low and moderate dilution rates. At high dilution rates nitrogenase activity increased steeply over the respiratory activity. Nitrogen-fixing cultures adapted to various oxygen concentrations were subjected to oxygen stress by increasing the oxygen concentration for 7 min. In all cases, this resulted in a complete inhibition (‘switch-off’) of nitrogenase activity. Upon restoration of the original oxygen concentration nitrogenase activity returned to a decreased level. The discussion arrives at the conclusion that some of the results are incompatible with the concept of respiratory protection of nitrogenase.

Energy metabolism and biosynthesis of Vibrio succinogenes growing with nitrate or nitrite as terminal electron acceptor

Abstract: 1. Growth of Vibrio succinogenes with nitrate as terminal electron acceptor was found to be a function of the following two catabolic reactions: $$HCO _2^ - + NO _3^ - + H^ + \to CO_2 + NO _2^ - + H_2 O$$ (a) $$3HCO _2^ - + NO _2^ - + 5H^ + \to 3CO_2 + NH _4^ + + 2H_2 O.$$ (b) The latter reaction (b) was responsible for growth with nitrite. 2. Either succinate or fumarate could serve as sole carbon source during growth with nitrate or nitrite. Biosynthesis from succinate proceeded via fumarate. The ATP requirement for cell synthesis from succinate was equal to that calculated earlier for growth with fumarate as carbon source and electron acceptor (Brounder et al. 1982). 3. The cell yield at infinite dilution rate (Ymax) as obtained with chemostat cultures was 8.5g dry cells/mol formate with either nitrate or nitrite as acceptor. This value amounts to 60% of that measured earlier with fumarate as acceptor (Mell et al. 1982). 4. Membrane vesicles prepared from V. succinogenes catalyzed electron transport from H2 to nitrate. The reaction was dependent on the menaquinone present in the membrane. 5. Electron transport with H2 and nitrite was coupled to the phosphorylation of ADP. The P/H2 ratio with nitrite was 40% of that measured with fumarate as acceptor using the same preparation. The phosphorylation but not the electron transport was abolished by an uncoupling agent.

Anaerobic acetate oxidation to CO2 by Desulfobacter postgatei

Abstract: All the enzymes required for the oxidation of acetate to CO2 via the citric acid cycle were found in Desulfobacter postgatei. To obtain in vivo evidence for the operation of this cycle, the sulfate reducing bacterium was grown on [14C]acetate in the presence of a large pool of 12CO2 and the incorporation of 14C into glutamate (≙ 2-oxoglutarate), aspartate (≙ oxaloacetate), and alanine (≙ pyruvate) was studied. The labelling data were found to be consistent with (i) the oxidation of acetate to CO2 via the reactions of the citric acid cycle, (ii) the synthesis of citrate via a citrate (si)-synthase, and (iii) the anaplerotic synthesis of oxaloacetate from acetate and 2 CO2 via pyruvate as intermediate.

Occurrence of polyglucose as a storage polymer in Desulfovibrio species and Desulfobulbus propionicus

Abstract: The occurrence of organic storage compounds in six strains of sulfate-reducing bacteria was investigated.

Clostridium lortetii sp. nov., a halophilic obligatory anaerobic bacterium producing endospores with attached gas vacuoles

Abstract: A strain of Clostridium was isolated from Dead Sea sediment, differing from the previously described Clostridium types in its halophilic character It required NaCl concentrations between 1 and 2 M, and optimal growth was found in 14–15 M NaCl at 30° C and in 17 M NaCl at 45° C In sporulating cells gas vacuoles developed, generally near the developing terminal endospore only, and these vacuoles remained attached to the mature endospore after degeneration of the vegetative cell Fermentation products included acetate, butyrate and hydrogen Glucose and a few other carbohydrates stimulated growth, though they were poorly utilized A new species name has been proposed for the organism: Clostridium lortetii

On the occurrence of enoate reductase and 2-oxo-carboxylate reductase in clostridia and some observations on the amino acid fermentation by Peptostreptococcus anaerobius

Abstract: Enoate reductase present in Clostridium kluyveri and Clostridium spec. La 1 could be detected in three strains of C. tyrobutyricum and ten clostridia belonging to the groups of proteolytic and saccharolytic or proteolytic species, respectively. In C. pasteurianum, C. butyricum and C. propionicum enoate reductase could not be found even after growth on (E)-2-butenoate. A 2-oxo-carboxylate reductase was present in rather low activities in the non-proteolytic clostridia which produce enoate reductase. High activities (up to 10 U/mg protein) of 2-oxo-carboxylate reductase were found in six of ten proteolytic clostridia. The substrate specificies of the enoate reductase and the 2-oxocarboxylate reductases from the proteolytic clostridia were determined with different α,β-unsaturated carboxylates (enoates) and 2-oxo-carboxylates, respectively. Enoates as well as 2-oxo-carboxylates are intermediates of the pathway by which amino acids are degraded. An explanation is offered for the long known but not understood fact that in the Stickland reaction isoleucine always acts as an electron donor and leucine and phenylalanine can be electron acceptors as well as donors.

Respiratory nitrate reduction by Desulfovibrio sp.

Abstract: Four strains of Desulfovibrio produced ammonium during growth on a defined medium containing 100 μg NO 3 - -N/ml in the presence of 1 mM sulfate. Ammonium was not produced by cultures grown in media devoid of sulfate nor in media containing 35 mM sulfate. The four strains of Desulfovibrio studied reduced 32.7–46% of the available nitrate to ammonium in 21 days incubation. Ammonium production from nitrate was confirmed by recovering 15N-enriched ammonium when 15N-enriched Ca(NO3)2 was utilized as the substrate for the reduction.

Isolation and characterization of two new methane-producing cocci: Methanogenium olentangi, sp. nov., and Methanococcus deltae, sp. nov.

Abstract: Two new methane-producing cocci have been isolated from separate sediment enrichments using a defined synthetic growth medium. A freshwater methanogen, Methanogenium olentangyi, sp. nov., was isolated from Olentangy River sediment, Columbus, Ohio. The organism was a non-motile, irregular coccus that produced methane from CO2 plus H2, and required acetate for growth. A marine methanogen, Methanococcus deltae, sp. nov., was isolated from Gulf of Mexico sediments and was a non-motile, irregular coccus that grew on CO2 plus H2, or on formate. The guanine-plus-cytosine content of the deoxyribonucleic acid of the isolates was 54.4 and 40.5 mol%, respectively.

Purification of cytochrome a1c1 from Nitrobacter agilis and characterization of nitrite oxidation system of the bacterium

Abstract: Cytochrome a1c1 was highly purified from Nitrobacter agilis. The cytochrome contained heme a and heme c of equimolar amount, and its reduced form showed absorption peaks at 587, 550, 521, 434 and 416 nm. Molecular weight per heme a of the cytochrome was estimated to be approx. 100,000–130,000 from the amino acid composition. A similar value was obtained by determining the protein content per heme a. The cytochrome molecule was composed of three subunits with molecular weights of 55,000, 29,000 and 19,000, respectively. The 29 kd subunit had heme c.

Transfer and expression of the herbicide-degrading plasmid pJP4 in aerobic autotrophic bacteria.

Abstract: Plasmid pJP4 encoding the ability to degrade the herbicide 2,4-dichlorophenoxyacetic acid (Tfd+) was transferred by conjugation from Escherichia coli JMP397 to various lithoautotrophic strains of Alcaligenes eutrophus and to the autotrophic bacterium Pseudomonas oxalaticus. The herbicide-degrading function of the plasmid was phenotypically expressed in all of the recipients. The majority of Tfd+ transconjugants also exhibited additional plasmid-encoded properties such as 3-chlorobenzoate degradation, resistance to mercuric ions, and sensitivity to the male-specific bacteriophage PR11. Furthermore, Tfd+ transconjugants were able to act as donors of plasmid pJP4. Physical evidence is presented by agarose gel electrophoresis showing that plasmid pJP4 coexisted with the resident plasmids widely distributed in this group of bacteria. However, in some of the hosts plasmid pJP4 was not stably maintained, had a reduced size and tended to form multimers.

Glucose repression of luminescence and luciferase in vibrio fischeri

Abstract: The autoinduction and glucose repression of luciferase synthesis in batch cultures and continuous cultures of Vibrio fischeri were investigate. As previously reported, a lag in luciferase synthesis occurred in glycerol-grown batch cultures and addition of d-glucose to the medium extended the lag period. A phosphate-limited chemostat culture with d-glucose as energy source (specific growth rate, μ=0.45 h-1) contained uninduced levels of luciferase. Luciferase activity increased to an induced level upon addition of c-AMP or autoinducer to such a chemostat culture while cell mass remained constant. Furthermore, when μ of a phosphate-limited chemostat culture containing d-glucose as energy source was decreased from 0.45 to 0.30 h-1, luciferase activity increased from an uniduced to induced level. After exogenously added c-AMP or autoinducer was diluted out of a phosphate-limited continous culture or after μ was increased to 0.45 h-1, luciferase activity remained at an induced level. Apparently, luciferase in V. fischeri was subject to a catabolite repression by d-glucose that could be overridden by autoinduction or by an autogenous control element.