Diversity of streptomycetes among specific Greek terrestrial ecosystems

Abstract

The diversity of streptomycetes isolated from different Greek terrestrial ecosystems using phenotypic identification, and the relationship between the number of species and the number of isolates as a diversity index, was studied. A total of 344 Streptomyces strains have been isolated and identified from diverse sites in the Greek territory, such as heavily disturbed agricultural areas and preserved forest areas, and from specific rhizosphere ecosystems. According to phenotypic identification, these strains belonged to 19 different cluster groups with a Willcox probability > 0·8. Streptomyces cyaneus, Strep. albidoflavus, Strep. diastaticus and Strep. exfoliatus were the most common cluster groups isolated from at least six different habitats. On the other hand, there were cluster groups that appeared in only one or two habitats, such as Strep. griseoflavus, Strep. rimosus, Streptoverticillium blastmyceticum, Nocardia mediterranea and Strep. fulvissimus. The diversity indices among the different cluster groups of each sampling area indicated that the different habitats can be sub‐divided into two main groups: rhizosphere habitats and non‐rhizosphere habitats, showing that the rhizosphere is one of the most important factors which determines the population structure of a specific soil area.

Determination of metabolic activity of streptomycetes in soil microcosms

“…Both strains were isolated from environments differing in soil structure and management regimes (type A soil: agricultural soil, high turnover and high sunlight irradiation resulting in higher soil temperatures; type B soil: forest soil, protected and preserved area, low sunlight irradiation because of litter surface layers). S. griseus CAG17 was chosen among the agricultural soil isolates, as it belongs to the most dominant species of this streptomycete population (Katsifas et al 1999). Aiming to study similar isolates in matters of genetic background another S. griseus strain (26K) was chosen among the forest area isolates.…”

Fluostatins C∼E, Novel Members of the Fluostatin Family Produced by Streptomyces Strain Acta 1383

“…Strain Acta 1383 was isolated from the rhizosphere of Ebenus sibthorpii (Fabaceae), an endemic plant found in low numbers in the Kaisariani area, a forest preserve site 4 km from the centre of Athens [6]. The soil at the sampling site is a sandy loam with a pH of 8.2.…”

Grecoketides A and B: New Naphthoquinones from Streptomyces sp. Acta 1362

“…[4] Batch fermentations of strain Acta 1362 were carried out in a 20-L fermentor by using a complex medium. The production of grecoketides A and B started after 38 h, reaching a maximum amount of 13 and 4.7 mg L -1 grecoketides A (1) and B (2), respectively, at a fermentation time of 160 h. The grecoketides were isolated from the culture filtrate by extraction with ethyl acetate and were purified and separated by a succession of chromatographic steps using diolmodified silica gel and step-gradient elution with dichloromethane/methanol and Sephadex LH-20 and Toyopearl HW-40 column chromatography with methanol as eluent.…”

“…We have developed an HPLC/UV/Vis database. [1] Strain Acta 1362, which was isolated from soil from the rhizosphere of an indigenous plant (Pinus brutia) of the island of Crete, [2] was of special interest because of the presence of a dominant peak in the culture filtrate extract at a retention time of 8.2 min and a minor congener with a retention time of 7.8 min in our standardized gradient elution profile. These two peaks correspond to grecoketide A (1) and grecoketide B (2), respectively ( Figure 1).…”