Ruegeria Atlantica Research Articles

Collagenase and Tyrosinase Inhibitory Compounds from Fish Gut Bacteria Ruegeria atlantica and Pseudoalteromonas neustonica.

Ruegeria atlantica and Pseudoalteromonas neustonica are fish gut bacteria that have been isolated from the guts of Pagrus major and Acanthopagrus schlegelii, respectively. A total of 22 compounds (1-22) were isolated from these two bacteria; 16 compounds (1-16) from R. atalantica and 6 compounds (17-22) from P. neustonica. Their chemical structures were elucidated by spectroscopic and spectrometric data analysis and chemical synthesis. Compounds 11 and 13 showed strong collagenase inhibitory activity, with 31.91% and 36.43% at 20 μM, respectively, comparable to or surpassing that of the positive control epigallocatechin gallate (EGCG, 34.66%). Also, compounds 11 and 14 exhibited a mild tyrosinase inhibitory effect of 6.73% and 13.68%, respectively. All of the tested compounds displayed no significant antibacterial activity against Escherichia coli and Bacillus subtilis up to 100 μM. The collagenase- and tyrosinase-inhibitory compound 11, cyclo(l-Pro-d-Leu), was found to be stable under heat (50 °C) and UV light (254 and 365 nm) for up to 6 days. These results indicate that compound 11 could be developed into a cosmeceutical with antiaging effects.

Quorum Quenching Strains Isolated from the Microbiota of Sea Anemones and Holothurians Attenuate Vibriocorallilyticus Virulence Factors and Reduce Mortality in Artemiasalina.

Interference with quorum-sensing (QS) intercellular communication systems by the enzymatic disruption of N-acylhomoserine lactones (AHLs) in Gram-negative bacteria has become a promising strategy to fight bacterial infections. In this study, seven strains previously isolated from marine invertebrates and selected for their ability to degrade C6 and C10-HSL, were identified as Acinetobacter junii, Ruegeria atlantica, Microbulbifer echini, Reinheimera aquimaris, and Pseudomonas sihuiensis. AHL-degrading activity against a wide range of synthetic AHLs were identified by using an agar well diffusion assay and Agrobacterium tumefaciens NTL4 and Chromobacterium violaceum CV026 and VIR07 as biosensors. High-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis indicated that this activity was not due to an AHL lactonase. All the strains degraded Vibrio coralliilyticus AHLs in coculture experiments, while some strains reduced or abolished the production of virulence factors. In vivo assays showed that strains M3-111 and M3-127 reduced this pathogen’s virulence and increased the survival rate of Artemia salina up to 3-fold, indicating its potential use for biotechnological purposes. To our knowledge, this is the first study to describe AHL-degrading activities in some of these marine species. These findings highlight that the microbiota associated with marine invertebrates constitute an important underexplored source of biological valuable compounds.

Lindane Bioremediation Capability of Bacteria Associated with the Demosponge Hymeniacidon perlevis.

Lindane is an organochlorine pesticide belonging to persistent organic pollutants (POPs) that has been widely used to treat agricultural pests. It is of particular concern because of its toxicity, persistence and tendency to bioaccumulate in terrestrial and aquatic ecosystems. In this context, we assessed the role of bacteria associated with the sponge Hymeniacidon perlevis in lindane degradation. Seven bacteria isolates were characterized and identified. These isolates showed a remarkable capacity to utilize lindane as a sole carbon source leading to a percentage of residual lindane ranging from 3% to 13% after 12 days of incubation with the pesticide. The lindane metabolite, 1,3–6-pentachloro-cyclohexene, was identified as result of lindane degradation and determined by gas chromatography–mass spectrometry (GC–MS). The bacteria capable of lindane degradation were identified on the basis of the phenotypic characterization by morphological, biochemical and cultural tests, completed with 16S rDNA sequence analysis, and assigned to Mameliella phaeodactyli, Pseudovibrio ascidiaceicola, Oceanicaulis stylophorae, Ruegeria atlantica and to three new uncharacterized species. The results obtained are a prelude to the development of future strategies for the in situ bioremediation of lindane.

Confluentimicrobium lipolyticum gen. nov., sp. nov., a novel lipolytic alphaproteobacterium isolated from the junction between the ocean and a freshwater spring, and emended description of Actibacterium mucosum Lucena et al. 2012.

A Gram-negative, aerobic, non-flagellated and coccoid, ovoid or rod-shaped bacterial strain, designated SSK1-4(T), was isolated from the junction between the ocean and a freshwater spring at Jeju island, South Korea. Strain SSK1-4(T) was found to grow optimally at 30°C, at pH 7.0-8.0 and in the presence of 2.0% (w/v) NaCl. In the neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences, strain SSK1-4(T) was found to form an evolutionary lineage independent of those of other genera within the family Rhodobacteraceae. Strain SSK1-4(T) exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Ruegeria lacuscaerulensis (94.99%), Ruegeria atlantica (94.98%) and Rhodovulum marinum (94.97%). Sequence similarities to the type strains of other recognized species were less than 94.87%. Strain SSK1-4(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c and cyclo-C19:0 ω8c as the major fatty acids. The polar profile of strain SSK1-4(T) was found to contain phosphatidylglycerol, sulfoquinovosyldiacylglycerol, an unidentified lipid and an unidentified aminolipid as major components, which distinguish it from those of the phylogenetically related taxa. The DNA G+C content of strain SSK1-4(T) was determined to be 58.4mol%. On the basis of the phylogenetic data and the chemotaxonomic and other phenotypic properties, strain SSK1-4(T) is considered to represent a new genus and species within the class Alphaproteobacteria, for which the name Confluentimicrobium lipolyticum gen. nov., sp. nov. is proposed. The type strain of C. lipolyticum is SSK1-4(T) (=KCTC 42136(T)=CECT 8621(T)). In addition, an emended description of Actibacterium mucosum Lucena et al. 2012 is also proposed.

Ruegeria arenilitoris sp. nov., isolated from the seashore sand around a seaweed farm

A Gram-negative, motile and rod-shaped bacterial strain, G-M8(T), which was isolated from seashore sand around a seaweed farm at Geoje island in South Korea, was characterized taxonomically. It grew optimally at 30-37°C, at pH 7.0-8.0 and in presence of 2% (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain G-M8(T) joined the cluster comprising the type strains of Ruegeria atlantica and Ruegeria lacuscaerulensis, showing 97.5% sequence similarity, by a bootstrap resampling value of 85.8%. It exhibited 16S rRNA gene sequence similarity values of 95.4-96.7% to the type strains of the other Ruegeria species. Strain G-M8(T) exhibited the highest gyrB sequence similarity value (88.5%) to the type strain of R. lacuscaerulensis. Strain G-M8(T) contained Q-10 as the predominant ubiquinone and C(18:1) ω7c as the predominant fatty acid. The polar lipid profile of strain G-M8(T) was similar to that of R. atlantica KCTC 12424(T). The DNA G+C content of strain G-M8(T) was 64.6mol% and its mean DNA-DNA relatedness values with R. atlantica KCTC 12424(T) and R. lacuscaerulensis KCTC 2953(T) were 18±5.3 and 10±3.6%, respectively. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, demonstrated that strain G-M8(T) is distinguished from other Ruegeria species. On the basis of the data presented, strain G-M8(T) (=KCTC 23960(T)=CCUG 62412(T)) represents a novel species of the genus Ruegeria, for which the name Ruegeria arenilitoris sp. nov. is proposed.

Ruegeria mobilis sp. nov., a member of the Alphaproteobacteria isolated in Japan and Palau

The taxonomic positions of two bacterial strains, MBIC01146(T) and MBIC01099, isolated from marine environments of Japan and Palau, respectively, were determined by using a polyphasic approach. The bacteria were aerobic, motile, Gram-negative rods and formed star-shaped aggregations. The G+C content of the genomic DNA ranged from 58.5 to 58.7 mol%. The major respiratory quinone was ubiquinone-10 and the predominant cellular fatty acids were C(16 : 0), C(18 : 1)omega6c and C(18 : 1)omega7c. 16S rRNA gene sequence analyses based on both neighbour-joining and maximum-parsimony methods revealed that strains MBIC01146(T) and MBIC01099 were positioned within the cluster comprising Ruegeria atlantica and Silicibacter lacuscaerulensis within subgroup alpha-3 of the Proteobacteria. The phenotypic and chemotaxonomic characteristics of the novel strains were similar to those of Ruegeria atlantica; however, DNA-DNA hybridization tests showed that the isolates represented an independent species. The isolates could be differentiated from Ruegeria atlantica based on several characteristics. Therefore, strains MBIC01146(T) and MBIC01099 are considered to represent a novel species of the genus Ruegeria, for which the name Ruegeria mobilis sp. nov. is proposed. The type strain is MBIC01146(T) (=NBRC 101030(T)=CIP 109181(T)). An emended description of Ruegeria atlantica Uchino et al. 1999 is also given.

Taxonomic evaluation of the genera Ruegeria and Silicibacter: a proposal to transfer the genus Silicibacter Petursdottir and Kristjansson 1999 to the genus Ruegeria Uchino et al. 1999

The taxonomic positions of the genera Ruegeria and Silicibacter were evaluated by a polyphasic investigation. It was evident from 16S rRNA gene sequence analysis that both genera are closely related as they formed a monophyletic clade with high sequence similarities (96.9-98.2 %). Several properties commonly found in these taxa strongly suggest that they should be classified in the same genus. Further, a comparative study based on DNA-DNA hybridization, phenotypic characterization and chemotaxonomic analysis indicated that the members of this clade, namely Ruegeria atlantica, Silicibacter lacuscaerulensis and Silicibacter pomeroyi, can be readily differentiated from each other. On the basis of the polyphasic data obtained in this study, all species of the genus Silicibacter should be transferred to the genus Ruegeria, since the latter has nomenclatural priority. It is therefore proposed that Silicibacter lacuscaerulensis and Silicibacter pomeroyi are transferred to the genus Ruegeria as Ruegeria lacuscaerulensis comb. nov. and Ruegeria pomeroyi comb. nov.

Pseudoruegeria aquimaris gen. nov., sp. nov., isolated from seawater of the East Sea in Korea

A Gram-negative, non-motile, rod-shaped bacterial strain, SW-255(T), was isolated from seawater from Hwajinpo, on the coast of the East Sea, Korea, and subjected to a polyphasic taxonomic study. Strain SW-255(T) grew optimally at pH 7.0-8.0 and 37 degrees C in the presence of 2 % (w/v) NaCl. It contained Q-10 as the predominant ubiquinone and C(18 : 1)omega7c as the major fatty acid. The DNA G+C content was 67.0 mol%. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain SW-255(T) is phylogenetically closely related to the genera Ruegeria and Silicibacter of the Alphaproteobacteria. The levels of 16S rRNA gene sequence similarity between strain SW-255(T) and the type strains of Ruegeria atlantica and two Silicibacter species were in the range 95.8-96.2 %. A phylogenetic tree based on gyrB sequences showed that strain SW-255(T) forms a distinct evolutionary lineage within the Alphaproteobacteria. Differential phenotypic properties, polar lipid profiles and DNA G+C contents, together with the phylogenetic distinctiveness, suggest that strain SW-255(T) should be distinguished from the members of the genera Ruegeria and Silicibacter. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain SW-255(T) represents a novel genus and species, for which the name Pseudoruegeria aquimaris gen. nov., sp. nov. is proposed. The type strain of Pseudoruegeria aquimaris is SW-255(T) (=KCTC 12737(T)=JCM 13603(T)).

Lissoclibadins 1—3, Three New Polysulfur Alkaloids, from the Ascidian Lissoclinum cf. badium.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Lissoclibadins 1–3, three new polysulfur alkaloids, from the ascidian Lissoclinum cf. badium

Three new polysulfur alkaloids, lissoclibadins 1 ( 1 )–3 ( 3 ), were isolated from the ascidian Lissoclinum sp. (cf. L. badium Monniot, F. and Monniot, C., 1996). The structures of 1– 3 were assigned on the basis of their spectral data, and the computational modeling study was utilized for 1 . Compound 1 had a trimeric structure of three identical aromatic anime moieties connected through two sulfide and a disulfide bonds. Compounds 2 and 3 were dimeric structures of the same unit as that of 1 connected through a sulfide and disulfide bonds ( 2 ) and two sulfide bonds ( 3 ). Compounds 1 and 2 inhibited the growth of the marine bacterium Ruegeria atlantica (15.2 mm at 20 μg/disk and 12.2 mm at 5 μg/disk, respectively) and 2 showed antifungal activity to Mucor hiemalis (13.8 mm at 50 μg/disk). Compounds 1– 3 were cytotoxic against HL-60 (IC 50=0.37, 0.21, and 5.5 μM, respectively).

Dinoroseobacter shibae gen. nov., sp. nov., a new aerobic phototrophic bacterium isolated from dinoflagellates

A novel group of aerobic anoxygenic phototrophic bacteria was isolated from marine dinoflagellates, and two strains were characterized in detail. Cells were Gram-negative cocci or ovoid rods and were motile by means of a single, polarly inserted flagellum. They were obligate aerobes requiring 1-7 % salinity. The optimal pH range for growth was 6.5-9.0 and the temperature optimum was 33 degrees C. The bacteria contained bacteriochlorophyll a and spheroidenone as the only carotenoid. The in vivo absorption spectrum displayed two maxima in the infrared region at 804 and 868 nm. The distinct 804 nm band indicates the presence of light-harvesting system 2. Various organic carbon sources were assimilated, including many carboxylic acids, glucose and glycerol, but not butyrate, ethanol or methanol. Dissimilatory nitrate reduction was found for both strains. The physiological characteristics of the new strains resembled those of Roseobacter denitrificans, but there were differences in the lipid composition. Based on 16S rRNA gene sequence analysis the new strains are relatively distant from other recognized species, with the closest relatives Jannaschia helgolandensis, Ruegeria atlantica and Rhodobacter veldkampii showing 94.1-93.4 % similarity. Similarity to Roseobacter denitrificans was only 92.2 %, in line with numerous other species of the Roseobacter group. Therefore, it is proposed to classify the strains in a new genus and species within the Roseobacter clade, Dinoroseobacter shibae gen. nov., sp. nov. The type strain is DFL 12(T) (=DSM 16493(T)=NCIMB 14021(T)).

Lissoclibadin 1, a Novel Trimeric Sulfur‐Bridged Dopamine Derivative, from the Tropical Ascidian Lissoclinum cf. badium.

Abstract A novel tribenzotetrathiepin alkaloid, named lissoclibadin 1 ( 1 ), has been isolated from the ascidian Lissoclinum sp. (cf. L . badium Monniot and Monniot, 1996). The gross structure was assigned on the basis of the spectral data, and one of two possible isomers was selected by the computational modeling study. Lissoclibadin 1 inhibited the growth of the marine bacterium Ruegeria atlantica (15.2 mm at 20 μg/disk).

Lissoclibadin 1, a novel trimeric sulfur-bridged dopamine derivative, from the tropical ascidian Lissoclinum cf. badium

A novel tribenzotetrathiepin alkaloid, named lissoclibadin 1 ( 1 ), has been isolated from the ascidian Lissoclinum sp. (cf. L. badium Monniot and Monniot, 1996). The gross structure was assigned on the basis of the spectral data, and one of two possible isomers was selected by the computational modeling study. Lissoclibadin 1 inhibited the growth of the marine bacterium Ruegeria atlantica (15.2 mm at 20 μg/disk).

Three New Chlorine Containing Antibiotics from a Marine‐Derived Fungus Aspergillus ostianus Collected in Pohnpei.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Three new chlorine containing antibiotics from a marine-derived fungus Aspergillus ostianus collected in Pohnpei.

A marine bacterium Ruegeria atlantica (designated as strain TUF-D) was isolated from a glass plate submerged in the coastal water. Three new chlorine containing compounds (1 to approximately 3), together with penicillic acid (4) were obtained from a marine-derived fungus Aspergillus ostianus strain TUF 01F313 isolated from a marine sponge at Pohnpei as antibacterial components against R. atlantica. The structures of three new antibiotics were determined based on their spectral data as 8-chloro-9-hydroxy-8,9-deoxyasperlactone (1), 9-chloro-8-hydroxy-8,9-deoxyasperlactone (2), and 9-chloro-8-hydroxy-8,9-deoxyaspyrone (3). Compound 1 inhibited the growth of R. atlantica at 5 microg/disc (inhibition zone: 12.7 mm), while 2 and 3 were active at 25 microg/disc (10.1 and 10.5 mm, respectively).