Gordonia pseudamarae sp. nov., a home for novel actinobacteria isolated from stable foams on activated sludge wastewater treatment plants.

The taxonomic status of two Gordonia strains, designated BEN371 and CON9T, isolated from stable foams on activated sludge plants was the subject of a polyphasic study which also included the type strains of Gordonia species and three authenticated Gordonia amarae strains recovered from such foams. Phylogenetic analyses of 16S rRNA gene sequences showed that these isolates formed a compact cluster suggesting a well-supported lineage together with a second branch containing the G. amarae strains. A phylogenomic tree based on sequences of 92 core genes extracted from whole genome sequences of the isolates, the G. amarae strains and Gordonia type strains confirmed the assignment of the isolates and the G. amarae strains to separate but closely associated lineages. Average nucleotide index (ANI) and digital DNA-DNA hybridisation (dDDH) similarities showed that BEN371 and CON9T belonged to the same species and had chemotaxonomic and morphological features consistent with their assignment to the genus Gordonia. The isolates and the G. amarae strains were distinguished using a range of phenotypic features and by low ANI and dDDH values of 84.2 and 27.0 %, respectively. These data supplemented with associated genome characteristics show that BEN371 and CON9T represent a novel species of the genus Gordonia. The name proposed for members of this taxon is Gordonia pseudamarae sp. nov. with isolate CON9T (=DSM 43602T=JCM 35249T) as the type strain.

Generic and functional diversity in endophytic actinomycetes from wild Compositae plant species at South Sinai - Egypt.

The diversity of culturable endophytic actinomycetes associated with wild Compositae plants is scantily explored. In this study, one hundred and thirty one endophytic actinobacteria were isolated from ten Compositae plant species collected from South Sinai in Egypt. Microscopic and chemotaxonomic investigation of the isolates indicated fourteen genera. Rare genera, such as Microtetraspora, and Intrasporangium, which have never been previously reported to be endophytic, were identified. Each plant species accommodated between three to eight genera of actinobacteria and unidentified strains were recovered from seven plant species. The generic diversity analysis of endophytic assemblages grouped the plant species into three main clusters, representing high, moderate and low endophytic diversity. The endophytes showed high functional diversity, based on forty four catabolic and plant growth promotion traits; providing some evidence that such traits could represent key criteria for successful residence of endophytes in the endosphere. Stress-tolerance traits were more predictive measure of functional diversity differences between the endophyte assemblages (Shannon's index, p = 0.01). The results indicate a potential prominent role of endophytes for their hosts and emphasize the potency of plant endosphere as a habitat for actinobacteria with promising future applications.

Mycobacterium psychrotolerans sp. nov., isolated from pond water near a uranium mine.

An acid-fast, rapidly growing, psychrotolerant short rod was isolated from pond water near a uranium mine. Phylogenetic analysis of the 16S rRNA gene sequence grouped this strain with the rapidly growing mycobacteria. The 16S rRNA gene sequence of isolate WA101T showed highest similarity to that of Mycobacterium sphagni DSM 44076T; however, DNA-DNA relatedness between the two strains was less than 30 %. Chemotaxonomic analyses, which included fatty acid and mycolic acid patterns, confirmed the classification of strain WA101T in the genus Mycobacterium. Physiological data, including antibiotic resistance, NaCl tolerance, carbon sources, temperature growth range and enzyme activities, were also determined. Based on the genotypic and phenotypic results it is proposed that isolate WA101T represents a novel Mycobacterium species. The name Mycobacterium psychrotolerans sp. nov. is proposed, with type strain WA101T (= DSM 44697T = LMG 21953T).