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Presence of Ecophysiologically Diverse Populations within Cobetia marina Strains Isolated from Marine Invertebrate, Algae and the Environments

Authors:
Elena P. Ivanova at RMIT University
Elena P. Ivanova
Richard Christen at University of Nice Sophia Antipolis
Richard Christen
Tomoo Sawabe
Tomoo Sawabe
Yulia V Alexeeva
Yulia V Alexeeva
Yulia V Alexeeva
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Abstract

Over the last decade, taxonomic surveys have recovered sixteen strains of Halomonas-like marine heterotrophic bacteria from different ecological habitats. The sixteen strains were isolated from three N.W. Pacific Ocean habitats: seawater, the mussel Crenomytilus grayanus and the degraded thallus of brown alga Fucus evanescens. These strains were subjected to a taxonomic investigation of their phenotypic/physiological, genetic, and phylogenetic features. Analysis indicates these bacteria belong to Cobetia marina. The study found all strains tolerated CdCl2 concentrations up to 875 mM. Taxonomically, the sixteen strains belong to the same species, nevertheless, their physiological features revealed distinguishing characteristics. For instance, strain KMM 296, recovered from the mussel Crenomytilus grayanus, was distinct from other C. marina strains by its ability to produce highly active alkaline phosphatase. The majority of C. marina strains that were isolated from degraded alga thallus appeared to have a particular metabolic specialisation by utilizing a range of easily assimilable monosaccharides. Notably, despite a high level of genetic similarity (80% of DNA relatedness), the phenotypic features of the strains isolated from degraded alga thallus differed with the type strain C. marina LMG 2217T. These differences suggest an ecologically adapted population of C. marina at a subspecies level.
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Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
Japanese Society of Microbial Ecology
NII-Electronic Library Service
... Many strains of the genus Cobetia have been reported as a source of molecules and activities of biotechnological interest, and the genomic analysis of these strains has revealed their potential for the biosynthesis of biosurfactants, aromatic hydrocarbon degradation, inorganic carbon fixation, the synthesis and production of polyhydroxy-alkanoates, surface colonization, and alginate degradation [4][5][6][7][8]. Earlier, in the course of a survey of Halomonaslike bacteria inhabiting different areas of the Northwest Pacific, the strain KMM 296 was isolated from the coelomic fluid of the mussel Crenomytilus grayanus, collected from the Sea of Japan, and initially identified as a representative of the species C. marina (formerly Deleya marina) [9,10]. Later, the results of phylogenetic analysis based on the 16S rRNA gene sequence revealed the closest relationship of the strain KMM 296 to the strain C. amphilecti NRIC 0815 T , with 100% sequence similarity. ...
... It should be noted that the genome of the strain KMM 296 (GenBank accession no. NZ_JQJA00000000.1) was sequenced [11] due to its ability to produce the highly active periplasmic alkaline phosphatase CmAP belonging to the PhoA alkaline phosphatase family [9][10][11][12][13][14]. Although the structural, biochemical, and catalytic properties of CmAP have been thoroughly studied, its exact physiological role still remains unknown due to the presence of several genes encoding for alkaline phosphatases with different structures in the KMM 296 genome [11]. ...
... The temperature range for growth was assessed on marine agar (MA). Tolerance to NaCl was assessed in medium containing 5 g Bacto Peptone (Difco), 2 g Bacto Yeast Extract (Difco), 1 g glucose, 0.02 g KH 2 PO 4 , and 0.05 g MgSO 4 ·7H 2 O per liter of distilled water with 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3,4,5,6,8,10,12,15,17,19, and 20% (w/v) of NaCl. Susceptibility to antibiotics was examined via the routine disc diffusion plate method. ...
In-Depth Genome Characterization and Pan-Genome Analysis of Strain KMM 296, a Producer of Highly Active Alkaline Phosphatase; Proposal for the Reclassification of Cobetia litoralis and Cobetia pacifica as the Later Heterotypic Synonyms of Cobetia amphilecti and Cobetia marina, and Emended Description of the Species Cobetia amphilecti and Cobetia marina
Article
Full-text available
  • Feb 2024
A strictly aerobic, Gram-stain-negative, rod-shaped, and motile bacterium, designated strain KMM 296, isolated from the coelomic fluid of the mussel Crenomytilus grayanus, was investigated in detail due to its ability to produce a highly active alkaline phosphatase CmAP of the structural family PhoA. A previous taxonomic study allocated the strain to the species Cobetia marina, a member of the family Halomonadaceae of the class Gammaproteobacteria. However, 16S rRNA gene sequencing showed KMM 296’s relatedness to Cobetia amphilecti NRIC 0815T. The isolate grew with 0.5–19% NaCl at 4–42 °C and hydrolyzed Tweens 20 and 40 and L-tyrosine. The DNA G+C content was 62.5 mol%. The prevalent fatty acids were C18:1 ω7c, C12:0 3-OH, C18:1 ω7c, C12:0, and C17:0 cyclo. The polar lipid profile was characterized by the presence of phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, and also an unidentified aminolipid, phospholipid, and a few unidentified lipids. The major respiratory quinone was Q-8. According to phylogenomic and chemotaxonomic evidence, and the nearest neighbors, the strain KMM 296 represents a member of the species C. amphilecti. The genome-based analysis of C. amphilecti NRIC 0815T and C. litoralis NRIC 0814T showed their belonging to a single species. In addition, the high similarity between the C. pacifica NRIC 0813T and C. marina LMG 2217T genomes suggests their affiliation to one species. Based on the rules of priority, C. litoralis should be reclassified as a later heterotypic synonym of C. amphilecti, and C. pacifica is a later heterotypic synonym of C. marina. The emended descriptions of the species C. amphilecti and C. marina are also proposed.
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... The genus accommodates Gram-stain-negative, aerobic, heterotrophic, halophilic and rodshaped bacteria, which can motile by means of a single polar flagellum and/or two to seven lateral flagella [1][2][3]. Earlier, in a course of survey of the Halomonas-like bacteria inhabitant different areas of NW Pacifica, the strain KMM 296 was isolated from the coelomic fluid of mussel C. grayanus, collected from the Sea of Japan, and identified as a representative of the species Cobetia marina (formerly Deleya marina) [4,5]. Later, the results of phylogenetic analysis based on the 16S rRNA gene sequences revealed the closest relationship of the strain KMM 296 to the strain C. amphilecti NRIC 815 T with 100% of their sequence similarity. ...
... Whereas, it was found to be identical to the type strain of the other validly published species of the genus Cobetia, C. amphilecti, with 100% sequence similarity [3]. This suggests that the mussel isolate KMM 296 can be placed in this species instead of C. marina, as it was proposed previously [5]. In addition, the comparative genome analysis and phylogenomic analysis of the family Halomonadaceae, implemented by Tang et al. [29] indicated the significant differences between C. marina JCM 21022 T and KMM 296 (formerly named C. marina KMM 296) resulted from the sequence insertions or deletions and chromosomal recombination. ...
... The genomic DNA G+C content of the strain KMM 296 was 62.5 mol% as determined by the genome sequencing data [9]. This value was slightly low than that obtained by the thermal denaturation method (62.7 mol%; [5]). The DNA-DNA relatedness between the mussel isolate and the strain Cobetia amphilecti NRIC 815 T , which was determined by the experimental hybridization method, was 92%. ...
Pangenome- and genome-based taxonomic classification inference for the marine bacterial strain KMM 296 producing a highly active PhoA alkaline phosphatase and closely related Cobetia species
Preprint
Full-text available
  • Nov 2023
A strictly aerobic, Gram-stain-negative, rod-shaped and motile bacterium, designated strain KMM 296, isolated from the coelomic fluid of mussel Crenomytilus grayanus, was investigated in details due to its ability to produce a highly active alkaline phosphatase of the structural family PhoA. A previous taxonomic study placed the strain to the species Cobetia marina, a member of the family Halomonadaceae of the class Gammaproteobacteria. However, the comprehensive phylogenetic analysis based on 16S rRNA gene sequencing revealed that the strain KMM 296 is most closely related to Cobetia amphilecti NRIC 815T with the 16S rRNA gene sequence similarity of 100%. The mussel isolate grew with 0.5-19% NaCl and at 4 - 42°C and hydrolysed Tweens 20 and 40, and L-tyrosine. The DNA G+C content was 62.5 mol%. The prevalent fatty acids were C18:1 ω7c, C12:0 3-OH, C18:1 ω7c, C12:0 and C17:0 cyclo. The polar lipid profile was characterized by the presence of phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, and unidentified aminolipid, phospholipid, and lipids. The major respiratory quinone was Q-8. According to phylogenetic evidence and similarity in the chemotaxonomic and genotypic properties of the mussel isolate and its nearest neighbors, the strain KMM 296 represents a member of the species C. amphilecti. A comparative analysis of the type strains genomes of the species C. amphilecti and C. litoralis showed that they belong to a single species. In addition, a high similarity of the genome sequences of C. pacifica NRIC 813T and C. marina LMG 2217T also allows suggesting the affiliation of these two species to one species. Based on the rules of priority, C. litoralis should be reclassified as a later heterotypic synonym of C. amphilecti, and C. pacifica is a later heterotypic synonym of C. marina. The emended descriptions of the species C. amphilecti and C. marina are also proposed.
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... Thirteen strains of the marine bacteria, isolated from coastal seawater and sediments from the Sea of Japan, marine invertebrates, the mussel Crenomytilus grayanus from the Sea of Japan and the deep-water sponge Esperiopsis digitate from the Sea of Okhotsk, and the red algae Ahnfeltia tobuchiensis from the Sea of Okhotsk, which are deposited in the Collection of Marine Microorganisms (KMM, G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far Eastern Branch, Russian Academy of Sciences, http://www.piboc.dvo.ru/), were assigned to the genus Cobetia by physiological, biochemical and molecular genetic parameters, using sequencing and phylogenetic analysis of their 16S rRNA genes (Table 1). However, the strain-specific metabolic versatility and ecophysiological diversity of these Cobetia isolates could not allow distinguishing between their species [9,20,21]. Thus, our study showed that 7 from 13 strains have 99.86-100% identity of the 16S rRNA genes simultaneously to two type strains C. marina LMG 2217 T (JCM 21022 T ) and C. pacifica KMM 3879 T (NRIC 0813 T ), one strain has 100% identity to the type strain C. crustatorum JCM 15644 T , and three strains have 100% identity to the type strain C. amphilecti KMM 1561 T (NRIC 0815 T ) ( Table 1). The strain Cobetia sp. ...
... The high percentage of 16S rRNA genes' (99.93-100%) and whole genomes' (88%) identities may mean that the strains of C. amphilecti and C. litoralis belong to the same species, but currently they are undergoing significant phenotypic and genotypic divergence because of adaptive evolution [32]. Possibly, the highly active alkaline phosphatase PhoA was acquired by the cosmopolite Cobetia strains during their trying colonization of an invertebrate digestive tract due to the putatively significant role of the enzyme in the relationship (symbiotic or pathogenic) between marine habitants, such as C. amphilecti KMM 296 and the mussel C. grayanus or C. amphilecti KMM 1561 T , and the eponymous sponge Amphilectus digitatus [7,9,20,24]. Meanwhile, their closely related strains of C. litoralis, including the type strain KMM 3880 T , were isolated predominantly from coastal sediments, therefore, they may not need such enzymatically active and specific alkaline phosphatase as CmAP [7,30]. ...
... Meanwhile, their closely related strains of C. litoralis, including the type strain KMM 3880 T , were isolated predominantly from coastal sediments, therefore, they may not need such enzymatically active and specific alkaline phosphatase as CmAP [7,30]. The 16S rRNA heterogeneity of C. litoralis KMM 7000 may be an additional evidence of the species divergence due to the adaptation to colonization of marine invertebrates, which are the predominant habitats of the closely related strains of the species C. amphilecti, including KMM 296 and KMM 1561 T [7,20,21]. Thus, a squid-vibrio symbiosis is feasible by modulation of the bacterial symbiont lipid A signaling by the host alkaline phosphatases facilitating its colonization of the juvenal squid's light organ [33]. The urgent need for mineralization and repair of the invertebrate's exoskeleton can also be a key factor in symbiosis with a carrier of a highly efficient nonspecific phosphatase like CmAP [9,30,34]. ...
Are the Closely Related Cobetia Strains of Different Species?
Article
Full-text available
  • Jan 2021
  • MOLECULES
Marine bacteria of the genus Cobetia, which are promising sources of unique enzymes and secondary metabolites, were found to be complicatedly identified both by phenotypic indicators due to their ecophysiology diversity and 16S rRNA sequences because of their high homology. Therefore, searching for the additional methods for the species identification of Cobetia isolates is significant. The species-specific coding sequences for the enzymes of each functional category and different structural families were applied as additional molecular markers. The 13 closely related Cobetia isolates, collected in the Pacific Ocean from various habitats, were differentiated by the species-specific PCR patterns. An alkaline phosphatase PhoA seems to be a highly specific marker for C. amphilecti. However, the issue of C. amphilecti and C. litoralis, as well as C. marina and C. pacifica, belonging to the same or different species remains open.
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... Meanwhile, Cobetia spp. are hydrocarbon-degrading and biosurfactant-producing, which display a functional potential to inhibit biofilm growth (72). We hypothesized that trophic diversity and different metabolic properties allow SUP05 and Cobetia to adapt to changes in nutrient levels. ...
Structure-Function Covariation of Phycospheric Microorganisms Associated with the Typical Cross-Regional Harmful Macroalgal Bloom
Article
Full-text available
Harmful macroalgal blooms represented by green tides have become a worldwide marine ecological problem. Unraveling the structure-function variation of phycospheric microorganisms and their ecological correlation with HMBs is challenging. This issue is still unclear in the natural dynamics of HMBs.
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... with the degradation of the brown alga Fucus evanescens [94], and while they appear not to directly hydrolyse this alga's polysaccharides, they benefit from mono-and disaccharides released after the initial degradation [94,95]. Given these previous observations, C. marina might have a role in accelerating disease progression by opportunistically scavenging on sugars or nutrients released from D. pulchra that has been impacted by the infection with Aquimarina sp. ...
Bacterial controlled mitigation of dysbiosis in a seaweed disease
Article
Full-text available
  • Aug 2021
Disease in the marine environment is predicted to increase with anthropogenic stressors and already affects major habitat-formers, such as corals and seaweeds. Solutions to address this issue are urgently needed. The seaweed Delisea pulchra is prone to a bleaching disease, which is caused by opportunistic pathogens and involves bacterial dysbiosis. Bacteria that can inhibit these pathogens and/or counteract dysbiosis are therefore hypothesised to reduce disease. This study aimed to identify such disease-protective bacteria and investigate their protective action. One strain, Phaeobacter sp. BS52, isolated from healthy D. pulchra, was antagonistic towards bleaching pathogens and significantly increased the proportion of healthy individuals when applied before the pathogen challenge (pathogen-only vs. BS52 + pathogen: 41–80%), and to a level similar to the control. However, no significant negative correlations between the relative abundances of pathogens and BS52 on D. pulchra were detected. Instead, inoculation of BS52 mitigated pathogen-induced changes in the epibacterial community. These observations suggest that the protective activity of BS52 was due to its ability to prevent dysbiosis, rather than direct pathogen inhibition. This study demonstrates the feasibility of manipulating bacterial communities in seaweeds to reduce disease and that mitigation of dysbiosis can have positive health outcomes.
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... They can also tolerate adverse conditions such as high pressure, salinity, temperature, and pH, and they have been reported as producers of several bioactive compounds [11] and PHA [31]. On the other hand, bacteria from the genus Cobetia (Gram-negative) [12] can be found in macroalgae environments [35], can form a biofilm, and they have been studied as a biological model in the biofouling phenomenon [36]. Besides, these bacteria present the ability to synthesize PHA and exopolysaccharides [13,37]. ...
Polyhydroxyalkanoate Production from Two Species of Marine Bacteria: A Comparative Study
Article
Full-text available
  • Sep 2020
There are few reports of polyhydroxyalkanoates production from marine microorganisms. This work aimed to explore the marine bacteria Cobetia sp. INV PRT122 and Bacillus sp. INV FIR18 isolated from the Colombian Caribbean Sea as poly-hydroxyalkanoates producers. The polymers were extracted, and structural analyses were completed to confirm their nature. Growth, accumulation, and sugar consumption kinetic studies were then conducted using glucose as a carbon source at 2%, 4%, 8%, 12% (w/v). A high degree of purity could be seen in the spectroscopy analysis through its signals, and the results indicated that the isolated polysaccharides had the same chemical structure as that of polyhydroxybutyrate. The results of the growth of the microorganisms and production of polyhydroxyalkanoates confirm that an excess of carbon affects the polymer production. The highest production was obtained from Bacillus sp. INV FIR18 using glucose at 2%, 30 °C, 140 rpm, and 144 h.
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... Kobayashi et al. (2012) isolated this species from big-eyed flathead (S. meerdervoortii) from Toyama Bay in Japan, which showed an ability to degrade phenol in seawater. In fact, C. marina can also be isolated from other marine ecological habitats such as seawater, mussel, and the degraded thallus of alga (Ivanova et al., 2005). In the genus Modicisalibacter, M. tunisiensis is the only species so far identified, and it has been isolated from an oilfield water-injection sample and a petroleum-contaminated salt marsh (Gam et al., 2007;Bonfá et al., 2013). ...
Biodegradation of phenol in saline or hypersaline environments by bacteria: A review
Article
  • Oct 2019
  • ECOTOX ENVIRON SAFE
With the continuous demand from industry for chemical raw materials, a large amount of high-salinity waste-water containing phenol is discharged into the aquatic environment, and the leakage of dangerous chemicals into the sea may lead to phenol pollution of the ocean. Phenol is a common chemical posing serious environmental hazard. Biodegradation is an effective, low-cost, environment-friendly method of removing phenol from water, but in hypersaline environments, traditional freshwater organisms are less efficacious. Here, at least 17 genera of bacteria from three phyla are found that can degrade phenol in different saline environments. The sources and taxonomy of halotolerant and halophilic bacteria are reviewed. Moreover, the pathway of phenol removal, kinetics of biodegradation, influencing factors, and recent treatment processes of wastewater are discussed.
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High natural PHA production from acetate in Cobetia sp. MC34 and Cobetia marina DSM 4741T and in silico analyses of the genus specific PhaC2 polymerase variant
Article
Full-text available
  • Dec 2021
  • MICROB CELL FACT
Background Several members of the bacterial Halomonadacea family are natural producers of polyhydroxyalkanoates (PHA), which are promising materials for use as biodegradable bioplastics. Type-strain species of Cobetia are designated PHA positive, and recent studies have demonstrated relatively high PHA production for a few strains within this genus. Industrially relevant PHA producers may therefore be present among uncharacterized or less explored members. In this study, we characterized PHA production in two marine Cobetia strains. We further analyzed their genomes to elucidate pha genes and metabolic pathways which may facilitate future optimization of PHA production in these strains. Results Cobetia sp. MC34 and Cobetia marina DSM 4741 T were mesophilic, halotolerant, and produced PHA from four pure substrates. Sodium acetate with- and without co-supplementation of sodium valerate resulted in high PHA production titers, with production of up to 2.5 g poly(3-hydroxybutyrate) (PHB)/L and 2.1 g poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/L in Cobetia sp. MC34, while C. marina DSM 4741 T produced 2.4 g PHB/L and 3.7 g PHBV/L. Cobetia marina DSM 4741 T also showed production of 2.5 g PHB/L from glycerol. The genome of Cobetia sp. MC34 was sequenced and phylogenetic analyses revealed closest relationship to Cobetia amphilecti . PHA biosynthesis genes were located at separate loci similar to the arrangement in other Halomonadacea . Further genome analyses revealed some differences in acetate- and propanoate metabolism genes between the two strains. Interestingly, only a single PHA polymerase gene ( phaC 2 ) was found in Cobetia sp. MC34, in contrast to two copies ( phaC 1 and phaC 2 ) in C. marina DSM 4741 T . In silico analyses based on phaC genes show that the PhaC 2 variant is conserved in Cobetia and contains an extended C-terminus with a high isoelectric point and putative DNA-binding domains. Conclusions Cobetia sp. MC34 and C. marina DSM 4741 T are natural producers of PHB and PHBV from industrially relevant pure substrates including acetate. However, further scale up, optimization of growth conditions, or use of metabolic engineering is required to obtain industrially relevant PHA production titers. The putative role of the Cobetia PhaC 2 variant in DNA-binding and the potential implications remains to be addressed by in vitro - or in vivo methods.
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Everything Is Everywhere: Physiological Responses of the Mediterranean Sea and Eastern Pacific Ocean Epiphyte Cobetia Sp. to Varying Nutrient Concentration
Article
Full-text available
  • Feb 2022
  • MICROB ECOL
Bacteria are essential in the maintenance and sustainment of marine environments (e.g., benthic systems), playing a key role in marine food webs and nutrient cycling. These microorganisms can live associated as epiphytic or endophytic populations with superior organisms with valuable ecological functions, e.g., seagrasses. Here, we isolated, identified, sequenced, and exposed two strains of the same species (i.e., identified as Cobetia sp.) from two different marine environments to different nutrient regimes using batch cultures: (1) Cobetia sp. UIB 001 from the endemic Mediterranean seagrass Posidonia oceanica and (2) Cobetia sp. 4B UA from the endemic Humboldt Current System (HCS) seagrass Heterozostera chilensis. From our physiological studies, both strains behaved as bacteria capable to cope with different nutrient and pH regimes, i.e., N, P, and Fe combined with different pH levels, both in long-term (12 days (d)) and short-term studies (4 d/96 h (h)). We showed that the isolated strains were sensitive to the N source (inorganic and organic) at low and high concentrations and low pH levels. Low availability of phosphorus (P) and Fe had a negative independent effect on growth, especially in the long-term studies. The strain UIB 001 showed a better adaptation to low nutrient concentrations, being a potential N2-fixer, reaching higher growth rates (μ) than the HCS strain. P-acquisition mechanisms were deeply investigated at the enzymatic (i.e., alkaline phosphatase activity, APA) and structural level (e.g., alkaline phosphatase D, PhoD). Finally, these results were complemented with the study of biochemical markers, i.e., reactive oxygen species (ROS). In short, we present how ecological niches (i.e., MS and HCS) might determine, select, and modify the genomic and phenotypic features of the same bacterial species (i.e., Cobetia spp.) found in different marine environments, pointing to a direct correlation between adaptability and oligotrophy of seawater.
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From gene to ecosystem : an integrative study of polysaccharide depolymerases bound to marine viruses
Thesis
  • Dec 2019
Viruses represent a driving force for the functioning and evolution of marine ecosystems. Through the lysis of their hosts, viruses profoundly influence the diversity and biogeochemistry of the ocean. In this study, I investigated the implications of polysaccharide depolymerases (or EPS depolymerases) associated to bacterial viruses (phages) in the regulation of viral activities and their consequences on ocean biogeochemistry. They confer to phages the ability to degrade the exopolysaccharides (EPS) excreted by their hosts in order to access their membrane receptors. Here, we studied integratively, from gene to ecosystem, the EPS depolymerases associated to 2 model phages (Podoviridae). A combination of approaches revealed that the genes encoding these activities are genetically distant from known sequences. An in-depth study showed that the enzyme Dpo31 (associated to Cobetia marina phage) is a glycoside hydrolases and revealed a novel molecular architecture. In the ocean, bacterial EPS constitute a significant pool of dissolved organic carbon. A microcosm experiment showed that viral depolymerases reduce the bioavailability of EPS and contribute to the production of refractory matter in the natural environment. Considering the predominance of viruses in the sea, this, so far, neglected process could have important implications for the functioning of the ocean.
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Two Species of Culturable Bacteria Associated With Degradation of Brown Algae Fucus Evanescens
Article
Full-text available
  • Apr 2002
The heterotrophic microbial enrichment community established during degradation of brown algae Fucus evanescens was characterized. A two-species bacterial community of marine culturable gamma-proteobacteria consisted of Pseudoalteromonas and Halomonas. The first member of the community, Pseudoalteromonas sp., was highly metabolically active, had bacteriolytic and hemolytic activities, produced proteinases (gelatinase and caseinase), lipases, DNases, and fucoidanhydrolases, laminaranases, alginases, pustulanases, beta-glucosidases, beta-galactosidases, beta-N-acetylglucosaminidases, and beta-xylosidases. The second member of the community, Halomonas marina, produced only caseinase and DNase, and it did not hydrolyze algal polysaccharides. Both members of the studied bacterial community utilized a range of easily assimilable monosaccharides and other low molecular weight organic substances. The results provide an evidence of the complex metabolic interrelations between two members of this culturable community. One of them Pseudoalteromonas sp., most likely plays the major role in the initial stages of algal degradation; the other one, H. marina, resistant to the bacteriolytic activity of the former, is able to utilize the products of degradation of polysaccharides.
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A Highly Active Alkaline Phosphatase from the Marine Bacterium Cobetia
Article
Full-text available
  • Jun 2005
An alkaline phosphatase with unusually high specific activity has been found to be produced by the marine bacterium Cobetia marina (strain KMM MC-296) isolated from coelomic liquid of the mussel Crenomytilus grayanus. The properties of enzyme, such as a very high specific activity (15000 DE U/1 mg of protein), no activation with divalent cations, resistance to high concentrations of inorganic phosphorus, as well as substrate specificity toward 5' nucleotides suggest that the enzyme falls in an intermediate position between unspecific alkaline phosphatases (EC 3.1.3.1) and 5' nucleotidases (EC 3.1.3.5).
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Factors influencing the activity of cellular alkaline phosphatase during growth and sporulation of Bacillus cereus
Article
  • Feb 1987
Alkaline phosphatase (EC 3.1.3.1) is synthesized in media with a low phosphate concentration (0.37 mM of total and 19 microM of inorganic phosphate, respectively) already during the exponential phase of growth of Bacillus cereus. The enzyme is repressed by higher phosphate concentrations (3.7 mM) during the whole growth period; during sporogenesis the enzyme activity in cells slightly increases even under these conditions. During growth the enzyme is not secreted into the medium, a minor amount being released after cessation of growth. The enzyme activity can be increased by adding Zn2+ ions (10 microM). When during growth without phosphate the pH of the medium decreases below 5.0, the enzyme activity temporarily decreases and growth is slowed down, followed by a subsequent increase of the enzyme activity. In this case the onset of sporulation is also delayed.
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De Ley J, Cattoir H, Reynaerts A.. The quantitative measurement of DNA hybridization from renaturation rates. Eur J Biochem 12: 133-142
Article
  • Feb 1970
A new method is proposed to measure relatedness amongst bacteria, based on renaturation rate determinations of DNA types and their mixture. The equations, relating the degree of binding with renaturation rates, are calculated for several cases. The optimal conditions for measurements are given. The method was checked in several ways. The advantages are summarized.
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Temperature and nutrient availability control growth rate and fatty acid composition of facultative psychrophilic Cobetia marina strain L-2
Article
  • Jun 2004
A facultative psychrophilic bacterium, strain L-2, that grows at 0 and 5 degrees C as minimum growth temperatures in complex and defined media, respectively, was isolated. On the basis of taxonomic studies, strain L-2 was identified as Cobetia marina. The adaptability of strain L-2 to cold temperature was higher than that of the type strain and of other reported strains of the same species. When the bacterium was grown at 5-15 degrees C in a defined medium, it produced a high amount of trans-unsaturated fatty acids. By contrast, in a complex medium in the same temperature range it produced a low amount of trans-unsaturated fatty acids. In the complex medium at 5 degrees C, the bacterium exhibited a three-fold higher growth rate than that obtained in the defined medium. Following a temperature shift from 11 to 5 degrees C, strain L-2 grew better in complex than in defined medium. Furthermore, when the growth temperature was shifted from 0 to 5 degrees C both the growth rate and the yield of strain L-2 growing in complex medium was markedly enhanced. These phenomena suggest that an upshift of the growth temperature had a positive effect on metabolism. The effects of adding complex medium components to the defined medium on bacterial growth rate and fatty acid composition at 5 degrees C were also studied. The addition of yeast extract followed by peptone was effective in promoting rapid growth, while glutamate addition was less effective, resulting in a cis-unsaturated fatty acid ratio similar to that of cells grown in the complex medium. These results suggest that the rapid growth of strain L-2 at low temperatures requires a high content of various amino acids rather than the presence of a high ratio of cis-unsaturated fatty acids in the cell membrane.
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