Microbial behaviour in salt-stressed ecosystems

Galinski, Erwin A.; Trüper, Hans G.

doi:10.1111/j.1574-6976.1994.tb00128.x

Cited by 367 publications

(219 citation statements)

References 80 publications

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“…In wetlands, these factors include light, redox potential, salinity, carbon substrate availability, inorganic N and P concentrations, Fe and Mo, availability and grazers (Capone & Kiene, 1988;Howarth et al, 1999). In saline environments, bacteria have to cope with ionic stress, which is balanced by intracellular osmoprotective compounds, many of which are sugars (e.g., disaccharide trehalose, Welsh & Herbert, 1999) or contain N (amino acids and their derivatives such as glycine betaine, Csonka, 1989;Galinski & Trüper, 1994). N fixation thus provides an important source of N in these, often N-limited, environments (Casselman et al, 1981;Whiting & Morris, 1986).…”

Section: Introductionmentioning

confidence: 99%

Heterotrophic nitrogen fixation in oligotrophic tropical marshes: changes after phosphorus addition

et al. 2009

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In order to determine the impact of nutrient enrichment on phosphorus (P) limited wetlands, we established experimental P additions in marshes throughout northern Belize. P significantly increased macrophyte primary production, which led to the rapid elimination of cyanobacterial mats. The replacement of cyanobacterial mats by macrophytes constrained autotrophic nitrogen (N) fixation, increased the quantity, and changed the quality of organic matter input to the sediments. We predicted that the activity of sediment heterotrophic N fixers will be impacted by these alterations in carbon input. We used the acetylene reduction technique to measure potential (glucose amended) nitrogenase activity (NA) in sediments from controls and treatment plots that have been P enriched for four years and dominated either by Eleocharis cellulosa, or Typha domingensis for two years. NA in P-enriched plots was 2-3 orders of magnitude higher than NA in controls. NA was positively correlated with the soil reactive P, both total organic and microbial carbon, live root biomass, and total phospholipid fatty acids (PLFA) as an indicator of active microbial biomass. It was negatively correlated with the concentration of ammonium-N. Path analysis revealed that the indirect effect of P on NA through the root biomass was more important than the direct effect of P. NA of the upper sediment layer was consistently higher in Eleocharis than in Typha dominated plots, despite the higher litter input by Typha. We feel that the higher levels of lignin and phenolics occurring in Typha litter, relative to Eleocharis, constrained NA in Typha plots.

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Section: Introductionmentioning

confidence: 99%

Heterotrophic nitrogen fixation in oligotrophic tropical marshes: changes after phosphorus addition

et al. 2009

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“…De telles variations osmotiques étant délétères pour les bactéries, celles-ci possèdent des systèmes de transport et/ou de synthèse d'osmoprotectants ou solutés compatibles qui assurent le maintien de l'homéostasie par leur accumulation dans le cytoplasme ou leur rejet selon le type de stress osmotique [4,5,17]. Les solutés compatibles sont des composés organiques qui peuvent être accumulés à forte concentration dans le cytoplasme sans interférer avec les processus cellulaires, la molécule majeure étant la glycine bétaïne (N,N,N-trimethylglycine), qui appartient à la famille des composés ammonium quaternaires [8].…”

Section: Introductionunclassified

La réponse au stress osmotique des bactéries lactiques Lactococcus lactis et Lactobacillus plantarum (mini-revue)

Roméo

Bouvier

Gutierrez

2001

Lait

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-Osmotic stress response of lactic acid bacteria Lactococcus lactis and Lactobacillus plantarum. In order to survive in a wide variety of environments, bacteria have evolved systems that protect themselves against environmental stress. Lactic acid bacteria grow in media where osmolarity is high and varies frequently and they must adjust their intracellular osmolarity in order to maintain the turgor pressure necessary for cell elongation. An osmotic upshock stops their growth and activates specific mechanisms which prevent cells death. The regulatory mechanisms of the response of Lactococcus lactis and Lactobacillus plantarum to an osmotic stress have drawn increasing attention in recent years, because of their use in industrial fermentations and their fundamental interest as Gram positive bacteria. The main response to osmotic stress is the accumulation in the cytoplasm of osmoprotectant organic compounds, the so-called "compatible solutes", which can accumulate to very high levels without deleterious effects on the cellular metabolism. In this review, we present the state of the art on the physiological and molecular responses of L. lactis and L. plantarum to an osmotic stress. osmotic regulation / lactic acid bacteria / stress / ABC transporter Résumé -Les bactéries sont capables de vivre dans des milieux extrêmement variés car elles possèdent des systèmes de protection efficaces contre les différents stress qu'elles peuvent rencontrer. Les bactéries lactiques vivent dans des habitats où l'osmolarité est souvent élevée et varie énormé-ment, alors que la pression osmotique intracellulaire doit rester relativement constante. Lorsqu'une bactérie subit un stress osmotique, dû à une forte augmentation de la concentration en sel dans l'environnement, sa croissance est arrêtée, et des mécanismes de détresse se mettent en place pour éviter la mort cellulaire. Les études sur la réponse au stress osmotique des bactéries lactiques Lactococcus lactis et Lactobacillus plantarum et les mécanismes moléculaires sous-jacents se sont développées depuis ces dernières années, du fait de l'intérêt économique (utilisation dans l'industrie agroalimentaire) et fondamental (bactéries à Gram positif) que représentent ces organismes. La principale réponse à un choc osmotique consiste en l'accumulation dans le cytoplasme de molécules protectrices, Lait 81 (2001) [49][50][51][52][53][54][55] 49

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“…It was suggested that betaine might be synthesized from glycine by a series of methylation reactions in archaebacterium Methanohalophilus portucalensis (12) and anaerobic phototrophic sulfur bacterium Ectothiorhodospira halochloris (13). Betaine synthesis from simple carbon sources has also been suggested in aerobic heterotrophic eubacterium Actinopolyspora halophila (13) and halotolerant cyanobacterium of Aphanothece halophytica (14).…”

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Isolation and Functional Characterization ofN-Methyltransferases That Catalyze Betaine Synthesis from Glycine in a Halotolerant Photosynthetic Organism Aphanothece halophytica

Waditee¹,

Tanaka²,

Aoki³

et al. 2003

Journal of Biological Chemistry

116

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Glycine betaine (N,N,N-trimethylglycine) is an important osmoprotectant and is synthesized in response to abiotic stresses. Although almost all known biosynthetic pathways of betaine are two-step oxidation of choline, here we isolated two N-methyltransferase genes from a halotolerant cyanobacterium Aphanothece halophytica. The most known biosynthetic pathways of betaine are the two-step oxidation of choline. Many bacteria, plants, and animals accumulate glycine betaine (here after betaine) under abiotic stress conditions (1-3). In these organisms, it was shown that betaine is synthesized by two steps, choline 3 betaine aldehyde 3 glycine betaine. The enzyme involved in the second step seems to be the same in plants, animals, and bacteria, namely NAD ϩ -dependent betaine-aldehyde dehydrogenase (4 -6). By contrast, different enzymes are involved for the first step. In plants, it was catalyzed by a novel Rieske-type iron-sulfur enzyme choline monooxygenase (7,8). In animals and many bacteria, the first step is catalyzed by membranebound choline dehydrogenase or soluble choline oxidase (9 -11). In some bacteria, choline dehydrogenase and choline oxidase also catalyze the second oxidation step (9 -11).It was suggested that betaine might be synthesized from glycine by a series of methylation reactions in archaebacterium Methanohalophilus portucalensis (12) and anaerobic phototrophic sulfur bacterium Ectothiorhodospira halochloris (13). Betaine synthesis from simple carbon sources has also been suggested in aerobic heterotrophic eubacterium Actinopolyspora halophila (13) and halotolerant cyanobacterium of Aphanothece halophytica (14). Recently, the methyltransferase genes that are involved in betaine synthesis have been isolated from E. halochloris and A. halophila (15). Two methyltransferase genes were involved in E. halochloris. One of gene products catalyzed the methylation reactions of glycine and sarcosine to sarcosine and dimethylglycine, respectively (EcGSMT), 1 whereas the other one catalyzed the methylations of sarcosine and dimethylglycine to dimethylglycine and betaine, respectively (EcSDMT) (15,16). By contrast, one ORF was found in A. halophila of which the N-and C-terminal parts had homologous sequences to those of EcGSMT and EcSDMT, respectively (15). The functionality of A. halophila methyltransferase was not well shown due to the formation of cell pellet when expressed in Escherichia coli.Glycine N-methyltransferase (GMT) catalyzing the methylation of glycine to sarcosine is known in mammalian cells although the enzymes catalyzing the further methylation steps do not occur (17,18). The homology of amino acid sequences between mammalian GMT and EcGSMT was low. No homologous sequences to those of EcGSMT, EcSDMT, and A. halophila methyltransferase could be found. Therefore, it was interesting to examine whether betaine is synthesized from glycine by three-step methylation reactions in other organisms.

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Microbial behaviour in salt-stressed ecosystems

Cited by 367 publications

References 80 publications

Heterotrophic nitrogen fixation in oligotrophic tropical marshes: changes after phosphorus addition

Heterotrophic nitrogen fixation in oligotrophic tropical marshes: changes after phosphorus addition

La réponse au stress osmotique des bactéries lactiques Lactococcus lactis et Lactobacillus plantarum (mini-revue)

Isolation and Functional Characterization ofN-Methyltransferases That Catalyze Betaine Synthesis from Glycine in a Halotolerant Photosynthetic Organism Aphanothece halophytica

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