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At least 19 recordsLinked to original sources
PubMed2005

Kordiimonas gwangyangensis gen. nov., sp. nov., a marine bacterium isolated from marine sediments that forms a distinct phyletic lineage (Kordiimonadales ord. nov.) in the 'Alphaproteobacteria'.

A marine bacterium, designated strain GW14-5(T), capable of degrading high-molecular-mass polycyclic aromatic hydrocarbons was isolated from the sediments of Gwangyang Bay, Republic of Korea, after enrichment culture for 2 years with a mixture of benzo[a]pyrene and pyrene. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate forms a phyletic lineage that is distinct from the seven known orders within the 'Alphaproteobacteria'. 16S rRNA gene sequence similarity of strain GW14-5(T) to all recognized bacterial species was not greater than 92%. The dominant fatty acids of the isolate were i-17:1 (46.2%), i-15:0 (15.1%) and i-17:0 (12.6%). The major respiratory quinone was MK-5, and the DNA G+C content was 39.3 mol%. Cells of strain GW14-5(T) were Gram-negative, motile, catalase-positive, oxidase-positive and weakly halophilic. Glucose, N-acetylglucosamine and maltose were utilized as sole carbon sources. The strain was positive for beta-glucosidase activity. Optimal growth of strain GW14-5(T) was at pH 7.0 and 37-40 degrees C and required the presence of 2% (w/v) NaCl. On the basis of this evidence, strain GW14-5(T) represents a novel genus and species in the 'Alphaproteobacteria' for which the name Kordiimonas gwangyangensis gen. nov., sp. nov. is proposed. The novel order Kordiimonadales is proposed for the distinct phyletic line represented by the genus Kordiimonas. The type strain is GW14-5(T) (=KCCM 42021(T)=JCM 12864(T)).

Alphaproteobacteria↗
PubMed2001

Characterization of the agarase system of a multiple carbohydrate degrading marine bacterium.

A marine bacterium strain 2-40 (2-40) degraded numerous complex carbohydrates, such as agar, chitin and alginate. It may play an important role in altering carbon fluxes in marine environments. End-product analyses revealed that 2-40 synthesized an agarase system that consisted of at least three enzymes, beta-agarase I, beta-agarase II and alpha-agarase, which acted in concert to degrade polymeric agar to D-galactose and 3,6-anhydro-L-galactose. The agarase system was shown to be both cell envelope-associated and extracellular, with the relative concentrations depending on the growth phase. The principal depolymerase, a beta-agarase I, hydrolysed agar to both neoagarotetrose and neoagarobiose, as identified by thin layer chromatography. This agarase had a mass of 98 kD and a Pi of 4.3. The agarase system was repressed by D-glucose and D-galactose and induced by agar, agarose, neoagarobiose, neoagarotetrose and neoagarohexose.

Carbohydrate Metabolism↗
PubMed1976

[Hydrocarbon metabolism in a marine bacterium].

The marine bacterium L.16.1 (Alcaligenes sp.) grows preferentially on alkanes (C10 to C18) with a very high growth yield (98 per cent); optimal growth depends strictly on the presence of a well-defined NaCl concentration (100 mM). Our strain is constitutive for the enzymatic systems responsible for the oxidation of alkanes to fatty acids, i.e. NADH-dependent hydroxylase, alcohol and aldehyde dehydrogenases, the latter of which located at the cytoplasmic membrane level. The aerobic oxidation of primary alcohols by particulate extracts prepared in the presence of 400 mM NaCl is NAD+-dependent (Km = 0.082 mM, Vmax = 238 with decanol). With extracts prepared in the absence of NaCl, Vmax undergoes a very strong decrease. On the contrary , the NAD+ (P)+-dependent oxidation of aldehydes is carried out anaerobically by the same extracts irrespective of the presence or the absence of added Na+ in the solutions used for the preparation of these extracts. A possible explanation for our results could be that Na+ acts on the enzymatic systems for which the maintenance of the membrane integrity is essential. This interpretation is consistent with the slowing down of the growth speed accompanying the decrease of NaCl concentration in the growth medium. With regard to alcohol and aldehyde-dehydrogenases, it is noteworthy that these enzymes behave like similar enzymatic activities induced by alkanes in other microorganisms.

Alcaligenes↗
PubMed1999

The effect of humic acid on uptake/adsorption of copper by a marine bacterium and two marine ciliates.

The effect of humic acid (HA) on Cu uptake by a bacterium and two bacterivorus ciliates was investigated. The presence of HA resulted in a statistically significant (p<0.001) decrease in Cu associated with bacteria that were exposed to 67 microg Cu L(-1). Complexation of Cu appears to lower the availability of Cu with respect to bacterial cell surface binding and uptake. For ciliates, 10 mg HA L(-1) significantly reduced uptake of Cu by Uronema, but did not reduce uptake of Cu by Pleuronema. Uronema exposed to 67 microg Cu L(-1) accumulated 54% less Cu when 10 mg HA L(-1) was present (0.50 pg ciliate(-1) vs 0.23 pg ciliate(-1)). Uronema feeding on V. natriegens, took up less than half as much Cu as unfed Uronema when exposed to Cu without HA (0.41 pg Cu fed ciliate(-1) vs 0.86 pg Cu unfed ciliate(-1), but only 40% less when exposed to Cu and HA (0.31 pg Cu fed ciliate(-1) vs 0.51 pg Cu unfed ciliate(-1)). The lower % reduction attributable to fed ciliates in the presence of HA suggests that some of the Cu associated with HA is available through trophic processes.

Animals↗
PubMed1971

Structural changes during lysis of a psychorophilic marine bacterium.

The marine psychrophile, a red, gram-negative motile rod with a single polar flagellum, is stable when suspended in 0.1 m Mg(2+) plus 0.5 m NaCl at 0 C and neutral pH but lyses if the salt composition of the medium is changed, the temperature raised above 20 C, or the pH lowered. Lysis is accompanied by a fall in turbidity, a release of ultraviolet-absorbing substances, and a loss of deoxyribonucleic acid and ribonucleic acid. Ultrastructural changes accompanying lysis were studied. Thin sections of cells fixed while intact showed a triple-layered cell wall and cytoplasmic membrane, each 6.0 to 7.5 nm thick. Mesosomes were also observed. Either Na(+) or Mg(2+) could maintain wall integrity, whereas Mg(2+) was needed for membrane integrity. In distilled water, lysis was very extensive, and much material was released as wall fragments and as vesicles which probably came from the wall and cytoplasmic membrane. Lysis at 37 C resulted in degradation of the wall and liberation of wall fragments. The cell membrane was rarely observed as a triple-layered structure in such temperature-lysed cells. After lysis at pH 5.0, the cell wall was distorted, and only a suggestion of the cell membrane remained. Replicas showed that this organism had a matted surface which was distorted under different conditions of lysis.

Bacteria↗
PubMed1989

Effect of Na Concentration and Nutritional Factors on the Lag Phase and Exponential Growth Rates of the Marine Bacterium Deleya aesta and of Other Marine Species.

Growth of the marine bacterium Deleya aesta in a succinate minimal medium showed increasingly long lag phases as Na was decreased below the optimum (200 to 500 mM). The minimum Na concentration permitting growth consistently was 15 mM. Supplementation of the medium with KHCO(3) (as a source of CO(2)) or yeast extract, especially in combination, reduced the lag phase, increased the rate of exponential growth, and allowed growth at 8 mM Na. KHCO(3) did not reduce the lag period but did increase the rate of exponential growth of Deleya venusta, Deleya pacifica, and Alteromonas haloplanktis 214. Yeast extract was active for all three. The effect of yeast extract on D. aesta could be reproduced by a mixture of amino acids approximating its amino acid composition. l-Alanine, l-aspartate, and l-methionine, in combination, were the most effective in reducing the lag phase, although not as effective as the complete mixture. Succinate, l-aspartate, and l-alanine were transported into the cells by largely independent pathways and oxidized at rates which were much lower at 10 than at 200 mM Na. l-Methionine was transported at a low rate in the absence of Na and at a higher rate at 10 mM but was not oxidized. Above 25 mM Na, the rate of transport of the carbon source was not the rate-limiting step for growth. It is concluded that a combination of transportable carbon sources reduced the lag period and increased the rate of exponential growth because they can be taken up independently and at low Na utilized simultaneously.

Journal Article↗
PubMed2003

Pseudoalteromonas sagamiensis sp. nov., a marine bacterium that produces protease inhibitors.

A marine bacterium producing protease inhibitors was isolated from neritic sea water and was studied phenotypically, genotypically and phylogenetically. This bacterium (strain B-10-31(T)) produced three types of protease inhibitor, namely, marinostatin, monastatin and leupeptin, which were considerably different in terms of their chemical structure and properties. Strain B-10-31(T) was a rod-shaped, non-spore-forming, Gram-negative, strictly aerobic bacterium that was motile by means of one polar flagellum. The strain required Na(+) for growth and exhibited optimal growth at 27 degrees C, pH 8.0 and 2 % (w/v) NaCl. It utilized various substrates, such as D-glucose, maltose, maltotriose, N-acetylglucosamine, L-threonine, L-serine, L-arginine, L-proline, L-alpha-alanine and L-glutamate, as the sole energy source. Ubiquinone-8 was the major respiratory quinone. The major fatty acids were C(16 : 0), C(16 : 1) omega7c, C(16 : 1) omega9c and C(18 : 1) omega7c. The G+C content of the DNA of strain B-10-31(T) was 42.0 mol%. Phylogenetic analysis, based on 16S rDNA sequences, showed that the strain clustered in the gamma-Proteobacteria. The aerobic marine bacterium Pseudoalteromonas bacteriolytica was the species most closely related to the new isolate (90.4 % 16S rDNA sequence similarity); other described species in the gamma-Proteobacteria cluster showed low levels of sequence similarity with strain B-10-31(T) (<90 %). Based on the above results, it is proposed that the novel marine bacterium should be classified as a new species, for which the name Pseudoalteromonas sagamiensis (type strain B-10-31(T)=JCM 11461(T)=DSM 14643(T)) is proposed.

DNA, Bacterial↗
PubMed1969

Antagonistic effect of monovalent cations in maintenance of cellular integrity of a marine bacterium.

The susceptibility of a marine bacterium, designated isolate c-A1, to lysis in distilled water and in salt solutions has been found to be a function of Na(+) concentration. Optical densities of cells pre-exposed to 0.05 m MgCl(2) were maintained in 1.0 m KCl, whereas those of cells pre-exposed to 1.0 m NaCl were not maintained at any KCl concentration tested. Cells transferred from MgCl(2) to low concentrations of NaCl underwent more extensive lysis than did those transferred to distilled water. The degree of disruption of cells transferred to distilled water from mixtures of 0.05 m MgCl(2) and NaCl (0 to 1.0 m) was dependent on the concentration of NaCl; similar results were obtained with LiCl, but not with KCl. In electron micrographs of thin sections, c-A1 cell envelopes consisted of two double-track layers which fractured and peeled apart on lysis after pre-exposure to NaCl-MgCl(2) mixtures. Envelope eruptions or "hernias" occurred only in lysed cells pre-exposed to NaCl alone. No evidence for a functional lytic enzyme was found. Comparative studies on a terrestrial pseudomonad with a multilayered envelope indicated that preexposure to NaCl did not enhance the susceptibility of this cell to lysis in distilled water. The lytic susceptibility of the marine bacterium is considered to be the consequence of competition between specific monovalent cations and Mg(++) for electrostatic interactions with components of the cell envelope of this organism.

Bacteria↗
PubMed1981

Growth characteristics af low Na+ concentration and the stability of the Na+ requirement of a marine bacterium.

Studies of the marine bacterium Alteromonas haloplanktis 214 (formerly referred to as marine pseudomonad B-16) showed that as the Na+ concentration in the growth medium decreased from 230 to 34 mM, the lowest concentration permitting growth, the length of the lag period preceding exponential growth increased. Once growth had begun, except for a slight reduction in rate of growth at 34 mM Na+, the generation time and extent of growth remained essentially constant over the range of Na+ concentrations tested. Plate counts showed that during the lag period the numbers of viable cells introduced as inoculum into a complex medium containing 33 mM Na+ decreased exponentially before increasing. Repeated subculture of the cells at 33 mM Na+ failed to eliminate the lag period or reduce the loss of viability of the cells. The viability loss and the lag period could be eliminated either by raising the NaCl concentration to 130 mM or by adding sufficient sucrose to make the osmotic pressure of the medium equal to that obtained by adding 130 mM NaCl. In a chemically defined medium, sucrose added to maintain tonicity reduced but did not eliminate the lag periods obtained at suboptimal Na+ concentrations. Increasing the number of cells plated on trypticase agar medium reduced the Na+ concentration required to permit growth. Evidence was obtained of a requirement of A. haloplanktis for Ca2+ for growth. Ca2+ spared to a small extent the requirement for Na+ for growth. Some 10(10) cells of a histidine-requiring, streptomycin-resistant mutant of A. haloplanktis 214, still viable after treatment with N-methyl-N'-nitro-N-nitrosoguanidine, were screened for capacity to grow in the absence of Na+. Since no non-Na+-requiring mutants were isolated, the requirement of this organism for Na+ would appear to be extremely stable.

Calcium↗
PubMed1980

Energy coupling to K+ transport in a marine bacterium.

Cells of the marine bacterium Alteromonas haloplanktis 214 ATCC 19855 (previously referred to as marine pseudomonad B-16) were depleted of K+ by washing with 0.1 M MgSO4. Washing with 0.05 M MgSO4 lowered the Vmax for K+ transport compared with washing with 0.1 M with 0.05 but did not change the Km, while washing with lower concentrations of MgSO4 caused loss of ultraviolet-absorbing material from the cells. K+ uptake was a strictly aerobic process and was accompanied by proton release. When an anaerobic suspension of cells was added to incubation mixtures containing increasing amounts of O2, intracellular ATP concentrations increased as the O2 concentration increased and reached near maximum values before K+ transport began. The O2 concentration initiating K+ transport caused transport to proceed at its maximum rate. For these experiments A. haloplanktis was depleted of ATP by incubating under anaerobic conditions. Incubating with either N,N'-dicyclohexyl carbodiimide (DCCD) or arsenate failed to deplete intact cells of ATP or prevent K+ transport. The inhibitory activity of DCCD for ATPase in membrane preparations was higher at 5 mM than at other MgSO4 concentrations and increased with time. Cyanide and the uncoupling agents tetrachloro-salicylanide (TCS) and carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) prevented K+ uptake while TSC and FCCP though not cyanide caused K+ to be released from K+-containing cells. It is concluded that the driving force for K+ transport in these cells is likely to be the membrane potential and that K+ transport may be gated.

Adenosine Triphosphatases↗
PubMed2005

Proteomic analysis of carbohydrate catabolism and regulation in the marine bacterium Rhodopirellula baltica.

The marine bacterium Rhodopirellula baltica is a model organism for aerobic carbohydrate degradation in marine systems, where polysaccharides represent the dominant components of biomass. On the basis of the genome sequence and a 2-D map of soluble proteins, the central catabolic routes of R. baltica were reconstructed. Almost all enzymes of glycolysis and TCA cycle were identified. In addition, almost all enzymes of the oxidative branch of the pentose phosphate cycle were detected. This proteomic reconstruction was corroborated by determination of selected enzymatic activities. To study substrate-dependent regulation in R. baltica, cells were adapted to growth with eight different carbohydrates and profiled with 2-DE for changes in protein patterns. Relative abundances of regulated proteins were determined using the 2-D DIGE technology and protein identification was achieved by PMF. Most of the up-regulated proteins were either dehydrogenases/oxidoreductases or proteins of unknown function which are unique for R. baltica. For only some of the regulated proteins, the coding genes are located in a physiologically meaningful genomic context. e.g., a ribose-induced alcohol dehydrogenase is encoded within an operon-like structure together with genes coding for a ribose-specific ABC-transporter. However, most of the regulated genes are randomly distributed across the genome.

Bacteria↗
PubMed1972

Feedback regulation of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthetase from a marine bacterium, Vibrio MB22.

A marine bacterium, Vibrio MB22, has been studied to determine the pattern of feedback regulation of the first enzyme unique to the biosynthesis of the aromatic amino acids, 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthetase. The crude extract was used to study response of the enzyme to various salts as well as possible feedback inhibitors. Ethylenediaminetetraacetic acid was found to be inhibitory to enzyme activity, and only CoCl(2), of the salts tested, allowed full recovery as well as apparent stimulation of the DAHP synthetase activity. The DAHP synthetase activity was inhibited solely by the aromatic amino acids, tyrosine, tryptophan, and phenylalanine, of the possible effectors tested. Further work demonstrated the existence of three isozymes of DAHP synthetase, each primarily inhibited by one of the aromatic amino acids.

Aldehyde-Lyases↗
PubMed1992

Roles of K+ and Na+ in pH homeostasis and growth of the marine bacterium Vibrio alginolyticus.

The marine bacterium Vibrio alginolyticus, containing 470 mM-K+ and 70 mM-Na+ inside its cells, was able to regulate the cytoplasmic pH (pH(in)) in the narrow range 7.6-7.8 over the external pH (pH(out)) range 6.0-9.0 in the presence of 400 mM-Na+ and 10 mM-K+. In the absence of external K+, however, pHin was regulated only at alkaline pH(out) values above 7.6. When the cells were incubated in the presence of unusually high K+ (400 mM) and 4 mM Na+, the pH(in) was regulated only at acidic pH(out) values below 7.6. These results could be explained by postulating a K+/H+ antiporter as the regulator of pH(in) over the pH(out) range 6.0-9.0. When Na(+)-loaded/K(+)-depleted cells were incubated in 400 mM-Na+ in the absence of K+, an inside acidic delta pH was generated at pH(out) values above 7.0. After addition of diethanolamine the inside acidic delta pH collapsed transiently and then returned to the original value concomitant with the extrusion of Na+, suggesting the participation of a Na+/H+ antiporter for the generation of an inside acidic delta pH. In the presence of 400 mM-K+, at least 5 mM-Na+ was required to support cell growth at pH(out) below 7.5. An increase in Na+ concentration allowed the cells to grow at a more alkaline pH(out). Furthermore, cells containing more Na+ inside could more easily adapt to grow at alkaline pH(out). These results indicated the importance of Na+ in acidification of the cell interior via a Na+/H+ antiporter in order to support cell growth at alkaline pH(out) under conditions where the activity of a K+/H+ antiporter is marginal.

Carrier Proteins↗
PubMed1984

K+/H+ antiporter functions as a regulator of cytoplasmic pH in a marine bacterium, Vibrio alginolyticus.

The marine bacterium, Vibrio alginolyticus, regulates the cytoplasmic pH at about 7.8 over the pH range 6.0-9.0. By the addition of diethanolamine (a membrane-permeable amine) at pH 9.0, the internal pH was alkalized and simultaneously the cellular K+ was released. Following the K+ exit, the internal pH was acidified until 7.8, where the K+ exit leveled off. The K+ exit was mediated by a K+/H+ antiporter that is driven by the outwardly directed K+ gradient and ceases to function at the internal pH of 7.8 and below. The Na+-loaded cells assayed in the absence of KCl generated inside acidic delta pH at alkaline pH due to the function of an Na+/H+ antiporter, but the internal pH was not maintained at a constant value. At acidic pH range, the addition of KCl to the external medium was necessary for the alkalization of cell interior. These results suggested that in cooperation with the K+ uptake system and H+ pumps, the K+/H+ antiporter functions as a regulator of cytoplasmic pH to maintain a constant value of 7.8 over the pH range 6.0-9.0.

Carrier Proteins↗
PubMed1977

Transhydrogenase activity in the marine bacterium Beneckea natriegens.

The marine bacterium, Beneckea natriegens, which has previously been reported not to form transhydrogenase, has been shown to synthesize a soluble energy-independent transhydrogenase (NADPH:NADP+ oxidoreductase, EC 1.6.1.1), though no energy-linked activity could be detected. The transhydrogenase is induced maximally in stationary phase cells and its formation is 70-90% repressed by raising the medium phosphate level from 0.33 to 3.3 mM. The enzyme is inhibited by arsenate, inorganic ortho- and pyrophosphate and by a range of organic phosphate-containing compounds, including 2'-AMP, which is an activator of several bacterial transhydrogenases.

Bacteria↗
PubMed1976

Extracellular nuclease produced by a marine bacterium. I. Extracellular deoxyribonuclease formation by a marine Vibrio sp.

Deoxyribonuclease (DNase) activity was found in the culture fluids of numerous marine bacteria isolated from seawater. Among these ogranisms, marine bacterium, Vibrio sp., strain No. 2, showed the highest deoxyribonucleic acid-hydrolyzing activity. This organism requires salts of seawater for both growth and extracellular DNase formation. The DNase activity could not be detected in the synthetic seawater culture liquid lacking magnesium ion, and DNase activity decreased in a calcium-deficient medium. The optimum temperature for the growth of this organism was between 15 and 25 degrees C. The formation of extracellular DNase was the greatest at 20 degrees C and less activity was found at 10 and 30 degrees C.

Culture Media↗
PubMed1997

Isolation and Characterization of Strain MMB-1 (CECT 4803), a Novel Melanogenic Marine Bacterium.

A novel marine melanogenic bacterium, strain MMB-1, was isolated from the Mediterranean Sea. The taxonomic characterization of this strain indicated that it belongs to the genus Alteromonas. Under in vivo conditions, L-tyrosine was the specific monophenolic precursor for melanin synthesis. This bacterium contained all types of activities associated with polyphenol oxidases (PPOs), cresolase (EC 1.18.14.1), catecholase (EC 1.10.3.1), and laccase (EC 1.10.3.2). These activities were due to the presence of two different PPOs. The first one showed all the enzymatic activities, but it was not involved in melanogenesis in vivo, since amelanogenic mutant strains obtained by nitrosoguanidine treatment contained levels of this PPO similar to that of the wild-type MMB-1 strain. The second PPO showed cresolase and catecholase activities but no laccase, and it was involved in melanogenesis, since this enzyme was lost in amelanogenic mutant strains. This PPO was strongly activated by sodium dodecyl sulfate below the critical micelle concentration, and it is a tyrosinase-like enzyme showing a lag period in its tyrosine hydroxylase activity that could be avoided by small amounts of L-dopa. This is the first report of a bacterium that contains two PPOs and also the first report of a pluripotent PPO showing all types of oxidase activities. The bacterium and the pluripotent PPO may be useful models for exploring the roles of PPOs in cellular physiology, aside from melanin formation. On the other hand, the high oxidizing capacity of the PPO for a wide range of substrates could make possible its application in phenolic biotransformations, food processing, or the cosmetic industry, where fungal and plant PPOs are being used.

Journal Article↗
PubMed2000

Involvement of an extracellular protease in algicidal activity of the marine bacterium Pseudoalteromonas sp. strain A28.

The marine bacterium Pseudoalteromonas sp. strain A28 was able to kill the diatom Skeletonema costatum strain NIES-324. The culture supernatant of strain A28 showed potent algicidal activity when it was applied to a paper disk placed on a lawn of S. costatum NIES-324. The condensed supernatant, which was prepared by subjecting the A28 culture supernatant to ultrafiltration with a 10,000-M(w)-cutoff membrane, showed algicidal activity, suggesting that strain A28 produced extracellular substances capable of killing S. costatum cells. The condensed supernatant was then found to have protease and DNase activities. Two Pseudoalteromonas mutants lacking algicidal activity, designated NH1 and NH2, were selected after N-methyl-N'-nitrosoguanidine mutagenesis. The culture supernatants of NH1 and NH2 showed less than 15% of the protease activity detected with the parental strain, A28. The protease was purified to homogeneity from A28 culture supernatants by using ion-exchange chromatography followed by preparative gel electrophoresis. Paper-disk assays revealed that the purified protease had potent algicidal activity. The purified protease had a molecular mass for 50 kDa, and the N-terminal amino acid sequence was determined to be Ala-Thr-Pro-Asn-Asp-Pro. The optimum pH and temperature of the protease were found to be 8.8 and 30 degrees C, respectively, by using succinyl-Ala-Ala-Pro-Phe-p-nitroanilide as a substrate. The protease activity was strongly inhibited by phenylmethylsulfonyl fluoride, diisopropyl fluorophosphate, antipain, chymostatin, and leupeptin. No significant inhibition was detected with EDTA, EGTA, phenanthroline or tetraethylenepentamine. These results suggest that Pseudoalteromonas sp. strain A28 produced an extracellular serine protease which was responsible for the algicidal activity of this marine bacterium.

Amylases↗