RESUMO
A spore-forming, rod-shaped Gram-strain-positive bacterium, strain 656.84T, was isolated from human faeces in 1984. It contained anteiso-C15 : 0 as the major cellular fatty acid, meso-diaminopimelic acid was found in the cell wall peptidoglycan, the polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and aminophospholipids as the major components, and the predominant menaquinone was MK-7. The DNA G+C content was 52.9âmol%. The results of comparative 16S rRNA gene sequence studies placed strain 656.84T within the genus Paenibacillus. Its closest phylogenetic relatives were Paenibacillus barengoltzii and Paenibacillus timonensis. Levels of DNA-DNA relatedness between strain 656.84T and Paenibacillus timonensis CIP 108005T and Paenibacillus barengoltzii CIP 109354T were 17.3 % and 36.8 %, respectively, indicating that strain 656.84T represents a distinct species. On the basis of phenotypic and genotypic results, strain 656.84T is considered to represent a novel species within the genus Paenibacillus, for which the name Paenibacillus faecis sp. nov. is proposed; the type strain is 656.84T ( = DSM 23593T = CIP 101062T).
Assuntos
Fezes/microbiologia , Paenibacillus/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , França , Humanos , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Paenibacillus/genética , Paenibacillus/isolamento & purificação , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
The objective of this study is to improve the viability after freeze-drying and during storage of delicate or recalcitrant strains safeguarded at biological resource centers. To achieve this objective, a joint experimental strategy was established among the different involved partner collections of the EMbaRC project ( www.embarc.eu ). Five bacterial strains considered as recalcitrant to freeze-drying were subjected to a standardized freeze-drying protocol and to seven agreed protocol variants. Viability of these strains was determined before and after freeze-drying (within 1 week, after 6 and 12 months, and after accelerated storage) for each of the protocols. Furthermore, strains were exchanged between partners to perform experiments with different freeze-dryer-dependent parameters. Of all tested variables, choice of the lyoprotectant had the biggest impact on viability after freeze-drying and during storage. For nearly all tested strains, skim milk as lyoprotectant resulted in lowest viability after freeze-drying and storage. On the other hand, best freeze-drying and storage conditions were strain and device dependent. For Aeromonas salmonicida CECT 894(T), best survival was obtained when horse serum supplemented with trehalose was used as lyoprotectant, while Aliivibrio fischeri LMG 4414(T) should be freeze-dried in skim milk supplemented with marine broth in a 1:1 ratio. Freeze-drying Campylobacter fetus CIP 53.96(T) using skim milk supplemented with trehalose as lyoprotectant resulted in best recovery. Xanthomonas fragariae DSM 3587(T) expressed high viability after freeze-drying and storage for all tested lyoprotectants and could not be considered as recalcitrant. In contrary, Flavobacterium columnare LMG 10406(T) did not survive the freeze-drying process under all tested conditions.