Assuntos
Biofilmes , Bactérias/genética , Fenômenos Fisiológicos Bacterianos , Técnicas Bacteriológicas , Biofilmes/crescimento & desenvolvimento , Corantes Fluorescentes , Genes Reporter , Proteínas de Fluorescência Verde , Hibridização In Situ , Proteínas Luminescentes/genética , Microscopia de Fluorescência , Técnicas de Sonda Molecular , Sondas RNA , RNA Bacteriano/genética , RNA Ribossômico/genéticaRESUMO
The novel fatty acid trans-9-methyl-10-octadecenoic acid was isolated from the coryneform bacterial strain LMG 3820 (previously misidentified as Arthrobacter globiformis) and identified by spectroscopic methods and chemical derivatization. This fatty acid is attached to the unusual lipid acyl phosphatidylglycerol. Five different species of this lipid type were identified; their structures were elucidated by tandem mass spectrometry and are reported here for the first time. Additionally, we identified three different cardiolipins, two bearing the novel fatty acid. The characteristic 10-methyl-octadecanoic acid was present only in phosphatidylinositol. Because of the unusual fatty acid pattern of strain LMG 3820, the 16S rDNA sequence was determined and showed regions of identity to sequences of Corynebacterium variabilis DSM 20132(T) and DSM 20536. All three strains possessed the novel fatty acid, identifying trans-9-methyl-10-octadecenoic acid as a potential biomarker characteristic for this taxon. Surprisingly, the fatty acid and relative abundances of phospholipids of Corynebacterium sp. strain LMG 3820 were similar to those of the type strain but different from those of Corynebacterium variabilis DSM 20536, although all three strains possessed identical 16S rDNA sequences and strains DSM 20132(T) and DSM 20536 have 90.5% DNA-DNA homology. This is one of the rare cases wherein different organisms with identical 16S rDNA sequences have been observed to present recognizably different fatty acid and lipid compositions. Since methylation of a fatty acid considerably lowers the transition temperature of the corresponding lipid resulting in a more flexible cell membrane, the intraspecific variation in the lipid composition, coinciding with the morphological and Gram stain reaction variability of this species, probably offers an advantage for this species to inhabit different environmental niches.
Assuntos
Corynebacterium/metabolismo , Ácidos Graxos/metabolismo , Fosfolipídeos/metabolismo , Corynebacterium/genética , Ácidos Graxos/química , Espectroscopia de Ressonância Magnética , Fosfolipídeos/química , Filogenia , Especificidade da Espécie , Espectrometria de Massas de Bombardeamento Rápido de ÁtomosRESUMO
The ability of glucocorticoid hormones to interact with glucocorticoid or mineralocorticoid receptors is modulated by 11 beta-hydroxysteroid dehydrogenases, interconverting active 11 beta-hydroxyglucocorticoids to inactive 11-ketones. This is, amongst others, important in maintaining a normal salt-water homeostasis. In this study, we determined the effect of treating rats for 4 days with the potassium sparing diuretic amiloride (5 mg/kg subcutaneously) or with 3% NaCl in drinking water on renal and hepatic microsomal oxidative and reductive 11 beta-hydroxysteroid dehydrogenase activities and immunoreactive 11 beta-hydroxysteroid dehydrogenase 1 protein. Treatment with amiloride resulted in a 1.5-fold rise of microsomal corticosterone 11 beta-oxidation rates in kidney (using NAD and NADP as cofactors) and in liver (for NADP only), but had no effect on microsomal 11-dehydrocorticosterone reduction. Renal 11 beta-hydroxysteroid dehydrogenase 1 immunoreactive protein was increased 1.6-fold by amiloride. NaCl treatment appeared to have no effect.
