Streptomyces odonnellii sp. nov., a proteolytic streptomycete isolated from soil under cerrado (savanna) vegetation cover.

A novel streptomycete, strain 594T, isolated from Brazilian soil collected under cerrado (savanna) vegetation cover is described. Strain 594T produced thermophilic chitinolytic proteases in assays containing feather meal and corn steep liquor as sole sources of carbon and nitrogen. The strain produced white to grey aerial mycelium and spiral chains of spiny-surfaced spores on the aerial mycelium and did not produce diffusible pigments. The ll-isomer of diaminopimelic acid was present in the cell wall and menaquinones were predominantly MK-9(H6) (52 %) and MK-9(H8) (30 %) with 6 % MK-9(H4) and slightly less than 1 % MK-9(H2). Polar lipids present were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown phospholipid. The major fatty acids were anteiso-C15 : 0, anteiso-C16 : 0, anteiso-C14 : 0 and anteiso-C17 : 0. The G+C content of the genomic DNA was 70.4 mol%. Phylogenetic analysis of the nearly complete 16S rRNA gene sequence indicated that it differed from described Streptomyces species. Multilocus sequence analysis (MLSA) using five housekeeping genes (atpD, gyrB, rpoB, recA and trpB) comparing Streptomyces type strains showed that the MLSA distance of strain 594T to the most closely related species was greater than the 0.007 threshold. The in silico DNA-DNA relatedness between the genome sequence of strain 594T and that of the phylogenetically nearest species was well below the species level recommendation. There was thus multiple evidence justifying the description of this strain as representing a novel species, for which the name Streptomyces odonnellii sp. nov. is proposed. The type strain is 594T (=IMPPG 594T=DSM 41949T=NRRL B-24891T).

Streptomyces lunalinharesii sp. nov., a chitinolytic streptomycete isolated from cerrado soil in Brazil.

A novel chitinolytic actinomycete isolated from a Brazilian cerrado soil, designated strain RCQ1071(T), was assigned to the genus Streptomyces on the basis of chemical and morphological characteristics. The almost-complete nucleotide sequence of the 16S rRNA gene of strain RCQ1071(T) was determined and also placed this strain in the genus Streptomyces. Phylogenetic analyses of 16S rRNA gene sequences showed that strain RCQ1071(T) formed a long branch in a group related to Streptomyces albulus, sharing approximately 98 % sequence similarity. Levels of DNA-DNA relatedness between strain RCQ1071(T) and members of this group, namely S. albulus DSM 40492(T), Streptomyces noursei DSM 40635(T) and Streptomyces yunnanensis DSM 41793(T), were 38.3, 27.8 and 46 %, respectively, strongly indicating that strain RCQ1071(T) was not a member of any of these species. The relatively long branch length within a stable clade together with the phenotypic data strongly supported that strain RCQ1071(T) represented a novel species. Based on the combination of physiological, phylogenetic and genomic data, strain RCQ1071(T) is suggested to represent a novel species of the genus Streptomyces, for which the name Streptomyces lunalinharesii sp. nov. is proposed. The type strain is RCQ1071(T) (=ATCC BAA-1231(T) =CIP 108852(T) =DSM 41876(T)).

Streptomyces lunalinharesii spores contain chitin on the outer sheath.

Chitin from Streptomyces lunalinharesii spores, detected on its outermost surface layer, was isolated and characterized by chemical and spectroscopic methods, transmission electron microscopy and flow cytometry analysis. Gold-chitinase- and gold-lectin (Lycopersicum esculentum agglutinin, LEA)-conjugated labels were used in microscopy experiments, whereas a fluorescence-lectin (LEA) conjugate was used in flow cytometry analysis. Chitin isolation consisted of several steps of hot alkali and nitrous acid treatment, and the final material was obtained in the colloidal form. The infrared and the 13C CP/MAS NMR spectra of Streptomyces sp. colloidal chitin and colloidal chitin obtained from commercial crab shell chitin were very similar. Incubation of the spores with gold-labeled lectin, or gold-labeled recombinant chitinase, showed the presence of gold particles around the spore surface, indicating the specific binding of the lectin or the recombinant chitinase with the chitin present on the outermost surface. Flow cytometry analysis, using the fluorescence-lectin conjugate, confirmed these results. According to scanning electron microscopy, S. lunalinharesii presented spore surface ornamentation belonging to the spiny group. This is the first detailed characterization of chitin on the spore's outermost layer from a Streptomyces species.