Mesonia oceanica sp. Nov., isolated from oceans during the tara oceans expedition, with a preference for mesopelagic waters

Strain ISS653T, isolated from Atlantic seawater, is a yellow pigmented, non-motile, Gram-reaction-negative rod-shaped bac-terium, strictly aerobic and chemoorganotrophic, slightly halophilic (1-15% NaCl) and mesophilic (4-37 °C), oxidase-and catalase-positive and proteolytic. Its major cellular fatty acids are iso-C15:0, iso-C15:0 2-OH, and iso-C17:0 3-OH; the major identified phospholipid is phosphatidylethanolamine and the major respiratory quinone is MK6. Genome size is 4.28 Mbp and DNA G+C content is 34.9 mol%. 16S rRNA gene sequence similarity places the strain among members of the family Flavobacteriaceae, with the type strains of Mesonia phycicola (93.2%), Salegentibacter mishustinae (93.1%) and Mesonia mobilis (92.9%) as closest relatives. Average amino acid identity (AAI) and average nucleotide identity (ANI) indices show highest values with M. mobilis (81% AAI; 78.9% ANI), M. phycicola (76% AAI; 76.3% ANI), Mesonia maritima (72% AAI, 74.9% ANI), Mesonia hippocampi (64% AAI, 70.8% ANI) and Mesonia algae (68% AAI; 72.2% ANI). Phylogenomic analysis using the Up-to-date-Bacterial Core Gene set (UBCG) merges strain ISS653T in a clade with species of the genus Mesonia. We conclude that strain ISS653T represents a novel species of the genus Mesonia for which we propose the name Mesonia oceanica sp. nov., and strain ISS653T (=CECT 9532T=LMG 31236T) as the type strain. A second strain of the species, ISS1889 (=CECT 30008) was isolated from Pacific Ocean seawater. Data obtained throughout the Tara oceans expedition indicate that the species is more abundant in the mesopelagic dark ocean than in the photic layer and it is more frequent in the South Pacific, Indian and North Atlantic oceans

Etude de quatre lichens marins, maritime ou terrestre et des bactéries associées : Evaluation de la diversité bactérienne et recherche de métabolites d’intérêt

Efficiency of currently used antibiotics is worldwide decreasing at a worrying rate, while we are faced with new and emerging pathogens. The majority of active natural products are isolated from the Ascomycetes or from the Actinobacteria. Among the 10000 known antibiotics, more than half are produced by bacteria of one single genus, Streptomyces. It is therefore most interesting to search for novel active molecules in yet under explored niches, such as mutualistic microbial symbioses. Lichens are complex organisms harboring bacterial communities on the surface and, more rarely, inside their thalli and present a model to discover new biomolecules. Optimization of extraction conditions of lichens has been developed. Chemical profiling by LC / MS of nine lichens (2 green algae Roccella fuciformis and R. phycopsis and 7 cyanolichens: Lichina confinis, L. pygmaea, Leptogium lichenoides, Synalissa symphorea, Collema auriforme, C. cristatum and C. fuscovirens) were made and compared with a "Molecular network" approach. This has allowed to identify the chemical similarity between all cyanolichens and between two lichen species containing green algae. On the other hand, further chemical study on R. fuciformis and R. phycopsis was conducted and ten different compounds were isolated. Nine of them have been isolated and identified by NMR and mass fragmentation pathways have been highlighted for five of them. In situ localization of their major respective metabolites (erythrin and roccellic acid for R. phycopsis and erythrin, lepraric acid and acetylportentol for R. fuciformis) was performed and showed a specific location in the lichen thallus. We focused also on the cultivable bacterial communities associated to three lichens from Brittany coast (France) (Roccella fuciformis, Lichina confinis, L. pygmaea) and one inland lichen from Austria (Collema auriforme) to find new secondary metabolites of interest. The abundance and the diversity of the bacterial communities associated to these lichens were showed: 247 strains were isolated and identified by 16S rRNA gene analysis. More than 30% of all strains express potential bioactive compounds and 12% represent probably new species. The secondary metabolites patterns of their cultivable associated bacteria were studied (MOLA1488, Streptomyces sp. and MOLA1416, Hoeflea sp.) and some active secondary metabolites were isolated (e.g. dicetopiperazines, pyrrole alkaloïds, phenoxazine derivatives …) showing biological properties. Finally, to highlight potential interactions between lichens and their associated bacteria, an approach of culture (lichen extracts and bacteria) was performed from 4 most abundant bacterial strains associated with Roccella fuciformis to (1) assess the impact of major metabolites (compounds 4) of this lichen on the growth of these four strains by a an optimized method of viability using MTT; and also to evaluate (2) the ability to bioconversion of these four strains of lepraric acid and erythrin. These bacteria have shown the ability to metabolize erythrin in orsellinic acid, but none of the four tested metabolites has affected their growth.L'efficacité des antibiotiques actuellement utilisés dans le monde entier est en baisse à un rythme inquiétant. La majorité des produits actifs naturels sont isolés des ascomycètes ou des Actinobactéries. Parmi les 10 000 antibiotiques connus, plus de la moitié sont produits par des bactéries du genre Streptomyces. Il est donc intéressant de rechercher de nouvelles molécules actives dans des niches encore sous explorés, tels que les symbioses microbiennes mutualistes. Ainsi, les lichens sont des organismes complexes abritant des communautés bactériennes à la surface et, plus rarement, à l'intérieur de leurs thalles et constituent un modèle d’étude pour la découverte de nouvelles molécules d’intérêts. Une optimisation des conditions d'extraction des lichens a été développée. Le profilage chimique par LC / MS de neuf lichens (2 à algues vertes : Roccella fuciformis et R. phycopsis et de 7 cyanolichens: Lichina confinis, L. pygmaea, Leptogium lichenoides, Synalissa symphorea, Collema auriforme, C. cristatum et C. fuscovirens) ont été effectués et comparés avec des approches de «molecular network". Cela a permis de souligner la similitude chimique entre tous les cyanolichens d’une part et les espèces lichéniques à algues vertes d’autre part. Une étude chimique plus approfondie de R. fuciformis et R. phycopsis a été par la suite effectuée et dix composés différents ont été isolés et identifiés. Neuf d'entre eux ont été isolés et identifiés par RMN et des voies de fragmentation ont été proposés pour cinq d'entre eux. Une étude de localisation in situ de leurs métabolites majeurs respectifs (érythrine et acide roccellique pour R. phycopsis et érythrine, acide léprarique et acetylportentol pour R. fuciformis) a été réalisée et a démontré leur emplacement spécifique au sein des thalles lichéniques. Les communautés bactériennes cultivables associées à trois lichens de la côte bretonne (France) (Roccella fuciformis, Lichina confinis, L. pygmaea) et un lichen terrestre récolté en Autriche (Collema auriforme) ont été étudiées afin de trouver de nouveaux métabolites d'intérêts. L'abondance et la diversité des communautés bactériennes associées à ces lichens a été montré: 247 souches ont été isolées et identifiées par l’étude du gène de l'ARNr 16S. Ainis, plus de 30% de toutes les souches expriment des gènes permettant la production potentielle des composés bioactifs et 12% appartiennent probablement à de nouvelles espèces bactériennes. Les métabolites secondaires de deux bactéries cultivables associées ont été étudiés (MOLA1488, Streptomyces sp. et MOLA1416, Hoeflea sp.) et certains métabolites spécialisés actifs ont été isolés (des dicétopipérazines, des alcaloïdes, des dérivés phénoxazine par exemple ...) présentant des propriétés biologiques intéressantes. Enfin, pour mettre en évidence les interactions possibles entre les lichens et leurs bactéries associées, une approche de culture (extraits lichéniques et bactéries associées) a été réalisée à partir de 4 souches bactériennes les plus abondantes associées à Roccella fuciformis pour (1) évaluer l'impact de ces métabolites sur la croissance de ces quatre souches et également, (2) à évaluer la capacité de bioconversion de l'acide leprarique et de l’érythrine. Ces bactéries ont montré la capacité de bio-converser l’érythrine en acide orsellinique, mais aucun des quatre métabolites testés n’a affecté leur croissance

Thalassocella blandensis : un nou bacteri marí

Un grup d'investigadors del Departament de Genètica i Microbiologia de la UAB, en col·laboració amb altres institucions espanyoles, han caracteritzat un nou bacteri marí que constitueix un nou gènere i una nova espècie de la família Cellvibrionaceae. La seva morfologia, la seva forma de vida i la seva baixa similitud genètica amb altres organismes de la mateixa família el fan candidat per a ser incorporat a la llista de nous descobriments en el camp de la microbiologia.Un grupo de investigadores del Departamento de Genética y Microbiología de la UAB, en colaboración con otras instituciones españolas, han caracterizado una nueva bacteria marina de la familia Cellvibrionaceae. Su morfología, su forma de vida y su baja similitud genética con otros organismos de la misma familia la hacen candidata para ser incorporada a la lista de nuevos descubrimientos en el campo de la microbiología.A group of researchers from the UAB Department of Genetics and Microbiology, in collaboration with other Spanish institutions, has characterized a new marine bacterium which constitutes a new genus and new species of the Cellvibrionaceae family. Its morphology, its way of life and its low genetic similarity with other organisms of the same family make it a candidate to be incorporated into the list of new discoveries in the field of microbiology

Thalassocella blandensis : un nou bacteri marí

Un grup d'investigadors del Departament de Genètica i Microbiologia de la UAB, en col·laboració amb altres institucions espanyoles, han caracteritzat un nou bacteri marí que constitueix un nou gènere i una nova espècie de la família Cellvibrionaceae. La seva morfologia, la seva forma de vida i la seva baixa similitud genètica amb altres organismes de la mateixa família el fan candidat per a ser incorporat a la llista de nous descobriments en el camp de la microbiologia.Un grupo de investigadores del Departamento de Genética y Microbiología de la UAB, en colaboración con otras instituciones españolas, han caracterizado una nueva bacteria marina de la familia Cellvibrionaceae. Su morfología, su forma de vida y su baja similitud genética con otros organismos de la misma familia la hacen candidata para ser incorporada a la lista de nuevos descubrimientos en el campo de la microbiología.A group of researchers from the UAB Department of Genetics and Microbiology, in collaboration with other Spanish institutions, has characterized a new marine bacterium which constitutes a new genus and new species of the Cellvibrionaceae family. Its morphology, its way of life and its low genetic similarity with other organisms of the same family make it a candidate to be incorporated into the list of new discoveries in the field of microbiology

Thalassocella blandensis gen. nov., sp. nov, a novel member of the family Cellvibrionaceae

9 pages, 1 figure, 3 tablesStrain ISS155T, isolated from surface Mediterranean seawater, has cells that are Gram-reaction-negative, motile, strictly aerobic chemoorganotrophic, oxidase-positive, unable to reduce nitrate to nitrite, and able to grow with cellulose as the sole carbon and energy source. It is mesophilic, neutrophilic, slightly halophilic and has a requirement for sodium and magnesium ions. Its 16S rRNA gene sequence places the strain among members of Cellvibrionaceae, in the Gammaproteobacteria, with Agarilytica rhodophyticola 017T as closest relative (94.3¿% similarity). Its major cellular fatty acids are C18¿:¿1, C16¿:¿0 and C16¿:¿1; major phospholipids are phosphatidyl glycerol, phosphatidyl ethanolamine and an unidentified lipid, and the major respiratory quinone is Q8. The genome size is 6.09 Mbp and G+C content is 45.2¿mol%. A phylogenomic analysis using UBCG merges strain ISS155T in a clade with A. rhodophyticola, Teredinibacter turnerae, Saccharophagus degradans and Agaribacterium haliotis type strain genomes, all of them possessing a varied array of carbohydrate-active enzymes and the potential for polysaccharide degradation. Average amino acid identity indexes determined against available Cellvibrionaceae type strain genomes show that strain ISS155T is related to them by values lower than 60¿%, with a maximum of 58¿% to A. rhodophyticola 017T and 57¿% to T. turnerae T7902T and S. degradans 2-40T. These results, together with the low 16S rRNA gene sequence similarities and differences in phenotypic profiles, indicate that strain ISS155T represents a new genus and species in Cellvibrionaceae, for which we propose the name Thalassocella blandensis gen. nov., sp. nov., and strain ISS155T (=CECT 9533T=LMG 31237T) as the type strainSequencing was funded by grant CTM2016-80095-C2-1-R to C.P.A. from the Spanish Ministerio de Economía y Competitividad. Additional funding was obtained by grant CTM2017-87736-R to S.G.A. from the Spanish Ministerio de Economía y CompetitividadWith the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI