Micromonospora fluminis sp. nov., isolated from mountain river sediment.

During a bioprospection of bacteria with antimicrobial activity, the actinomycete strain A38T was isolated from a sediment sample of the Carpintero river located in the Gran Piedra Mountains, Santiago de Cuba province (Cuba). This strain was identified as a member of the genus Micromonospora by means of a polyphasic taxonomy study. Strain A38T was an aerobic Gram-positive filamentous bacterium that produced single spores in a well-developed vegetative mycelium. An aerial mycelium was absent. The cell wall contained meso-diaminopimelic acid and the whole-cell sugars were glucose, mannose, ribose and xylose. The major cellular fatty acids were isoC15:0, 10 methyl C17:0, anteiso-C17:0 and iso-C17:0. The predominant menaquinones were MK-10(H4) and MK-10(H6). Phylogenetic analysis of 16S rRNA gene sequences revealed that this strain was closely related to Micromonospora tulbaghiae DSM 45142T (99.5 %), Micromonospora citrea DSM 43903T (99.4 %), Micromonospora marina DSM 45555T (99.4 %), Micromonospora maritima DSM 45782T (99.3 %), Micromonospora sediminicola DSM 45794T (99.3 %), Micromonospora aurantiaca DSM 43813T (99.2 %) and Micromonospora chaiyaphumensis DSM 45246T (99.2 %). The results of OrthoANIu analysis showed the highest similarity to Micromonospora chalcea DSM 43026T (96.4 %). However, the 16S rRNA and gyrB gene sequence-based phylogeny and phenotypic characteristics provided support to distinguish strain A38T as a novel species. On the basis of the results presented here, we propose to classify strain A38T (=LMG 30467T=CECT 30034T) as the type strain of the novel species Micromonospora fluminis sp. nov.

Nocardiopsis dassonvillei subsp. crassaminis subsp. nov., isolated from freshwater sediment, and reappraisal of Nocardiopsis alborubida Grund and Kroppenstedt 1990 emend. Nouioui et al. 2018.

An actinomycete, strain D1T, was isolated from a freshwater sediment sample collected from the San Pablo river in the La Risueña community, Santiago de Cuba province, Cuba. The strain was identified as a member of the genus Nocardiopsis by means of a polyphasic taxonomic study. It produced a light yellow non-fragmented substrate mycelium, a white well-developed aerial mycelium and straight to flexuous hyphae. No specific spore chains were observed. Strain D1T contained meso-diaminopimelic acid, no diagnostic sugars, and MK-10(H2), MK-10(H4), MK-10 and MK-10(H6) as predominant menaquinones, but not phosphatidylcholine as diagnostic polar lipid of the genus Nocardiopsis. The predominant fatty acids were iso-C16 : 0, 10-methyl-C18 : 0 and anteiso-C17 : 0. Strain D1T showed the highest degree of 16S rRNA gene sequence similarity to Nocardiopsis synnematoformans DSM 44143T (99.8 %), Nocardiopsis dassonvillei subsp. albirubida NBRC 13392T (99.8 %) and Nocardiopsis dassonvillei subsp. dassonvillei DSM 43111T (99.6 %). A genomic OrthoANIu value between D1T and N. dassonvillei subsp. dassonvillei DSM 43111T of 97.63 % and a dDDH value of 78.9 % indicated that strain D1T should be classified in N. dassonvillei. However, phenotypic characteristics distinguished strain D1T from its nearest neighbour taxon. On basis of these results we propose to classify strain D1T (=LMG 30468T=CECT 30033T) as a representative of a novel subspecies of the genus Nocardiopsis, for which the name Nocardiopsis dassonvillei subsp. crassaminis subsp. nov. is proposed. In addition, the genomic distance between N. dassonvillei subsp. albirubida NBRC 13392T and N. dassonvillei subsp. dassonvillei DSM 43111T as determined through OrthoANIu (93.64 %) and dDDH (53.40 %), along with considerable phenotypic and chemotaxonomic differences reported in earlier studies, indicated that the classification of this taxon as Nocardiopsis alborubida Grund and Kroppenstedt 1990 is to be preferred over its classification as N. dassonvillei subsp. albirubida Evtushenko et al. 2000.

Evaluación de dos métodos de conservación para Kluyveromyces marxianus CCEBI 2011 en la Colección de Cultivos del CEBI / Evaluation of two conservation methods for Kluyveromyces marxianus CCEBI 2011 at the CEBI Culture Collection

La elección de un método de conservación debe permitir mantener, entre otros parámetros, la viabilidad, pureza y estabilidad de las propiedades de una cepa. Kluyveromyces marxianus CCEBI 2011 es una levadura con atractivas potencialidades biotecnológicas, conservada en la Colección de Cultivos del CEBI mediante dos métodos: transferencia periódica y agua destilada estéril (método de Castellani). En este trabajo, para determinar la eficacia y calidad de los dos métodos utilizados para la conservación de K. marxianus CCEBI 2011, se evaluaron parámetros como viabilidad, pureza e identidad y propiedades biotecnológicas. Por ambos métodos se obtuvo una elevada pureza y una viabilidad de 5,31x1010 células/mL y 6,8x1010 células/mL por el método de Castellani y transferencia periódica, respectivamente. En este último se alcanzaron los mayores valores de tolerancia a etanol (11%), producción de etanol (6,08 ± 0,11 g/L) y actividad pectinolítica (15,29 ± 1,71 U/mL). En los dos métodos se corroboró la clasificación taxonómica de esta cepa como K. marxianus, según el análisis de las regiones ITS1-gen 5,8S ARNr-ITS2. Se demostró que los métodos de conservación empleados son efectivos, y que han mantenido con calidad las potencialidades biotecnológicas de este microorganismo por más de 10 años.

The election of a conservation method should allow maintaining, among other parameters, the viability, purity and stability of the properties of a strain. Kluyveromyces marxianus CCEBI 2011 is a yeast with attractive biotechnological potentialities, conserved at the CEBI Culture Collection by two methods: periodic transfer and sterile distilled water (Castellani method). In this study for determining the efficacy and quality of the two methods being used for the conservation of K. marxianus, we evaluated parameters such as viability, purity, identity and biotechnological properties. For both methods we obtained a high purity and a viability of 5.31x1010 cells/mL and 6.8x1010 cells/ mL, for the Castellani method and the periodic transfer method respectively. In this last method we obtained the highest values for ethanol tolerance (11%), ethanol production (6.08 ± 0.11 g/L) and pectonolitic activity (15.29 ± 1.71 U/mL). For the two methods the taxonomic classification of this strain as K. marxianus was corroborated according to the analysis of the ITSI-gen 5.8S ARNr-ITS2 regions. It was shown that the conservation methods being used are effective and that they have maintained the quality of the biotechnological potentialities of this microorganism during more than 10 years.

Antimicrobial activity of extracts from Tamarindus indica L. leaves.

Tamarindus indica L. leaves are reported worldwide as antibacterial and antifungal agents; however, this observation is not completely accurate in the case of Cuba. In this article, decoctions from fresh and sun dried leaves, as well as fluid extracts prepared with 30 and 70% ethanol-water and the pure essential oil from tamarind leaves were microbiologically tested against Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, Pseudomona aeruginosa and Candida albicans. Aqueous and fluid extracts were previously characterized by spectrophotometric determination of their total phenols and flavonoids, while the essential oil was chemically evaluated by gas chromatography/mass spectroscopy (GC/MS). Experimental data suggest phenols as active compounds against B. subtilis cultures, but not against other microorganisms. On the other hand, the essential oil exhibited a good antimicrobial spectrum when pure, but its relative low concentrations in common folk preparations do not allow for any good activity in these extracts.