Actinomadura alkaliterrae sp. nov., isolated from an alkaline soil

Actinomadura soli sp. nov., isolated from the top soil layer on basaltic material in Turkey

An actinobacterium, designated 14C53^T, was isolated from a soil sample on basaltic material from Samsun, Turkey. The growth ranges for NaCl concentration and pH of strain 14C53^T were quite limited and the growth temperature range of the strain was 20-37 °C, with an optimum at 28 °C. Phylogenetic analysis of 16S rRNA gene sequences revealed that strain 14C53^T was most closely related to Actinomadura geliboluensis A8036^T (98.5 % similarity value), but in the phylogenetic tree, it formed a clade with Actinomadura alkaliterrae D310A^T. The genome tree revealed a close relationship between the strain and Actinomadura pelletieri DSM 43383^T. However, the digital DNA-DNA hybridization and average nucleotide identity values between strain 14C53^T with Actinomadura geliboluensis A8036^T and Actinomadura pelletieri DSM 43383^T were 28.6-30.2 % and 84.3-85.5 %, respectively, and comparative analyses based on the genome sequences demonstrated that it represents a novel species of the genus Actinomadura. The genome size of strain 14C53^T was approximately 9.0 Mb and the genomic DNA G+C content of the strain was 71.3 mol%. The major cellular fatty acids of strain 14C53^T were C_16 : 0 and iso-C_16 : 0. Strain 14C53^T contained meso-diaminopimelic acid as the diamino acid in the cell-wall peptidoglycan. The predominant menaquinones were MK-9(H₈) and MK-9(H₆). Based on evidence collected from the phenotypic, genotypic and phylogenetic analyses, a novel species Actinomadura soli sp. nov. is proposed, with 14C53^T (=DSM 104447^T=KCTC 39878^T) as the type strain.

CONTROL DE Aedes aegypti (DIPTERA: CULICIDAE) MEDIANTE ACTINOBACTERIAS FORMADORAS DE BIOPELÍCULAS

El phylum Actinobacteria incluye miembros productores de compuestos bioinsecticidas. No obstante, la sobreexplotacion de metabolitos derivados de Streptomyces ha conllevado a explorar nuevas moléculas provenientes de bacterias no estreptomicetos para contrarrestar la resistencia a insecticidas químicos en Aedes aegypti. Concordantes con el uso de bioagentes ecológicos, esta investigación caracterizó actinobacterias formadoras de biopelículas con el fin de evaluar su dinámica de crecimiento, actividad larvicida y efectos subletales. La identificación, crecimiento de biopelículas y bioactividades se realizaron por cultivos, análisis de imágenes por fotomicrografía y bioensayos. Los resultados mostraron que las biopelículas pertenecen a Pseudonocardiaceae (PsA1TA) y Corynebacteriaceae (CoA2CA) característicamente dependientes del revestimiento cuticular. PsA1TA coloniza estructuras membranosas de tórax y abdomen con microcolonias aleatoriamente distribuidas que desarrollan a extensas biopelículas mono y biestratificadas, al cubrir cuatro veces la amplitud toracoabdominal (envergadura infectiva entre 1010 µm a 1036 µm). En contraste, CoA2CA envuelve radialmente estructuras esclerotizadas cefálica y anal al triplicar la amplitud de tales órganos (1820 a 2030 µm y 1650 a 1860 µm, respectivamente). Las biopelículas ejercieron mortalidad diferenciada a todos los estadios larvales, no obstante, PsA1TA resultó más mortal y virulento en el segundo estadio larval (58 %-96 horas, TL50: 3,4 días), mientras que CoA2CA lo fue en el cuarto estadio larval (85 %-96 horas, TL50: 2,5 días). CoA2CA indujo emergencia incompleta de adultos farados y despliegue de tarsos curvos en emergentes, además de revestir con robustas biopelículas cadáveres larvarios. Las biopelículas actinobacterianas revelaron ejercer función larvicida y respuestas subletales en A. aegypti.

Actinomadura roseirufa sp. nov., producer of semduramicin, a polyether ionophore

The taxonomic position of 'Actinomadura roseorufa' LMG 30035^T, a semduramicin-producing mutant of strain ATCC 53666^P, which was isolated from a soil sample collected in Yamae Village, Kamamoto, Japan, was clarified in the present study using a polyphasic approach. This Gram-positive, aerobic actinomycete formed a well-developed, extensively branched, non-fragmenting substrate and aerial mycelia which differentiated into single, smooth-appearing spores. Based on analysis of nearly complete 16S rRNA gene sequence, strain LMG 30035^T was found to be closely related to the type strains of Actinomadura fibrosa ATCC 49459^T (98.88 %) and Actinomadura formosensis JCM 7474^T (98.82 %) (pairwise similarity values in parentheses). Digital DNA-DNA hybridisation experiments revealed unambiguously that strain LMG 30035^T represents a novel Actinomadura species (OrthoANIu values less than 83.1 %; dDDH values less than 27.2 % with type strains of validly named Actinomadura species). Analysis of the cell wall revealed the presence of meso-diaminopimelic acid in the peptidoglycan. The whole-cell sugars were glucose, madurose, galactose, ribose and rhamnose. The major polar lipids included phosphatidylinositol and diphosphatidylglycerol. The predominant menaquinones were MK-9(H₆), MK-9(H₈), MK-9(H₄) and MK-9(H₂). The major fatty acids were C_16 : 00, 10-methyl C_18 : 0, C_18 : 1  ω9c and C_18 : 00. The DNA G+C content of its genome was 72.5 mol%. In summary, these characteristics distinguish strain LMG 30035^T from validly named species of the genus Actinomadura, and therefore, we propose to classify this strain formally as the novel species Actinomadura roseirufa sp. nov. with LMG 30035^T (=CECT 9808^T,=ATCC 53664^T) as the type strain.

Jiangella anatolica sp. nov. isolated from coastal lake soil

A novel actinobacterial strain, designated GTF31^T, was isolated from a coastal soil sample of Gölcük Lake, a crater lake in southwest Anatolia, Turkey. The taxonomic position of the strain was established using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences and showed that the strain is closely related to Jiangella gansuensis DSM 44835^T (99.4%), Jiangella alba DSM 45237^T (99.3%) and Jiangella muralis DSM 45357^T (99.2%). Optimal growth was observed at 28 °C and pH 7-8. Whole cell hydrolysates were found to contain LL-DAP, glucose, mannose, rhamnose and ribose. The predominant menaquinone was identified as MK-9(H₄). The polar lipid profile was found to contain diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, glycophospholipids and unidentified phospholipids. The major fatty acids were identified as anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. The G + C content of the type strain was determined to be 72.5% and the size of the draft genome is 7.0 Mb. The calculated digital DDH values between strain GTF31^T and the type strains of J. gansuensis, J. alba, J. muralis and Jiangella alkaliphila ranged from 24.4 to 34.4% and ANI values ranged between 81.0 and 87.9%. Based upon the consensus of phenotypic and phylogenetic analyses as well as whole genome comparisons, strain GTF31^T (= DSM 100984^T = CECT 9378^T) is proposed to represent the type strain of a novel species, Jiangella anatolica sp. nov.

Actinomadura barringtoniae sp. nov., an endophytic actinomycete isolated from the roots of Barringtonia acutangula (L.) Gaertn

A novel actinomycete strain, designated GKU 128^T, isolated from the roots of an Indian oak tree [Barringtonia acutangula (L.) Gaertn.] at Khao Khitchakut district, Chantaburi province, Thailand, was characterized by using a polyphasic approach. The strain formed a branched substrate and aerial mycelia which differentiated into straight to flexuous chains of smooth-ornamented spores. Analysis of the cell wall revealed the presence of meso-diaminopimelic acid and N-acetylmuramic acid in the peptidoglycan. The whole-cell sugars were glucose, madurose, mannose, rhamnose and ribose. Mycolic acids were absent. The major phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannoside. The predominant menaquinones were MK-9(H6), MK-9(H8), MK-9(H0) and MK-9(H4). The major fatty acids were C16 : 0, C18 : 1ω9c and 10-methyl C18 : 0 (tuberculostearic acid). The genomic DNA G+C content was 70.5 mol%. Based on 16S rRNA gene sequence analysis, strain GKU 128^T was closely related to the type strains of Actinomadura nitritigenes NBRC 15918^T (99.2 % sequence similarity) and Actinomadura fibrosa JCM 9371^T (98.7 %). The levels of DNA-DNA relatedness between strain GKU 128^T and the closely related type species were less than 19 %. On the basis of phenotypic and genotypic characteristics, strain GKU 128^T could be distinguished from its closely related type strains and represents a novel species of the genus Actinomadura, for which the name Actinomadura barringtoniae sp. nov. (=TBRC 7225^T=NBRC 113074^T) is proposed.