Actinomycetes are considered an inexhaustible source of chemically diverse secondary metabolites. In addition to the genera Streptomyces, Micromonospora, and Actinoplanes, coryneform and nocardioform bacteria have been used in screening programs for new compounds of medical and biotechnological importance (5, 8).In the course of a program aimed at isolating actinomycetes that have potential for producing novel bioactive compounds, we isolated a large number of strains from different soils. In about 65 of these strains diaminobutyric acid (DAB) was the diagnostic diamino acid in the peptidoglycan. These strains had morphological and chemotaxonomic characteristics that placed them near the genera Agromyces and Clavibacter.In this paper we describe the isolation and characterization of two strains which differed markedly from the members of the genera Agromyces (27), Clavibacter, and Rathayibacter (26) that have been described. On the basis of our morphological, physiological, and biochemical data, as well as the results of our 16s ribosomal DNA (rDNA) analysis, we concluded that these strains belong to a new genus and species, for which we propose the name Agrococcus jenensis. These strains have been deposited in the German Collection of Microorganisms and MATERIALS AND METHODSBacterial strains and cultural conditions. Strain 2002-39/lT was isolated from a sample of frozen compost soil obtained near Jena, Germany, at a depth of about 10 cm. Isolation of this organism involved dilution plating on nutrient agar containing 2% peptone, a pancreatic digest (meat, fish), 0.5% NaCI, and 1.2% agar. Strain ST54 was isolated from the sandstone surface of the Alte Pinakothek building in Munich, Germany. The Agromyces and Cluvibacter type strains which we used in this study are listed in Table 1. General laboratory cultivation was performed on solid medium or in liquid rich (R) medium (25) containing 1% Bacto Peptone (Difco Laboratories), 0.5% yeast extract, 0.5% Casamino Acids, 0.2% meat extract, 0.5% malt extract, 0.2% glycerol, 0.1% MgSO, -7H,O, and 0.005% Tween 80 (pH 7.2) at 28°C.Morphological and physiological characteristics. Cell morphology was determined by examining cultures of different ages by phase-contrast microscopy. Colony morphology was studied by using a stereomicroscope. For scanning electron microscopy an 18-h-old culture of strain 2002-39/lT on an agar plate was suspended in a phosphate-buffered salt solution. The cells were fixed with 0 5 % glutaraldehyde, washed, and dehydrated in a series containing increasing concentrations of ethanol. After sputter coating with gold-palladium, the cells were observed with a Zeiss model 962 scanning electron microscope.

Several strains of the fungus Rhizopus microsporus harbour endosymbiotic bacteria for the production of the causal agent of rice seedling blight, rhizoxin, and the toxic cyclopeptide rhizonin. R. microsporus and isolated endobacteria were selected for freeze–fracture electron microscopy, which allowed visualization of bacterial cells within the fungal cytosol by their two parallel-running envelope membranes and by the fine structure of the lipopolysaccharide layer of the outer membrane. Two representatives of bacterial endosymbionts were chosen for phylogenetic analyses on the basis of full 16S rRNA gene sequences, which revealed that the novel fungal endosymbionts formed a monophyletic group within the genus Burkholderia. Inter-sequence similarities ranged from 98.94 to 100 %, and sequence similarities to members of the Burkholderia pseudomallei group, the closest neighbours, were 96.74–97.38 %. In addition, the bacterial strains were distinguished from their phylogenetic neighbours by their fatty acid profiles and other biochemical characteristics. The phylogenetic studies based on 16S rRNA gene sequence data, together with conclusive DNA–DNA reassociation experiments, strongly support the proposal that these strains represent two novel species within the genus Burkholderia, for which the names Burkholderia rhizoxinica sp. nov. (type strain, HKI 454T=DSM 19002T=CIP 109453T) and Burkholderia endofungorum sp. nov. (type strain, HKI 456T=DSM 19003T=CIP 109454T) are proposed.

New gram-positive bacteria were isolated from 1-year-old sludge from a wastewater treatment plant. The isolates are coccoid to rod-shaped, nonmotile aerobes that form neither spores nor mycelia. They are characterized by a peptidoglycan with directly cross-linked rneso-diaminopimelic acid (type Aly), by the presence of menaquinone MK-S(H,), and by the lack of mycolic acids. The strains have complex fatty acid patterns with i-C16:o and straight-chain saturated and unsaturated fatty acids as major components. The G+C content of the DNA is 70 mol%. The results of chemotaxonomic studies and a 16s ribosomal DNA sequence comparison support our proposal to assign these bacteria to a new genus, the genus Janibacter gen. nov.; the type species is Junibucter Zirnosus sp. nov., and the type strain of J. Zirnosus is strain HKI 83 (= DSM 11140).Both spore-forming and asporogenous actinomycetes have been screened during the last few years for useful bioactive compounds (13,39). The asporogenous organisms play important roles in mineralization of environmentally hazardous chemicals, such as polycyclic aromatic hydrocarbons (22), and in biotechnological production of natural products (23,26,29).To isolate new actinomycetes with new biological activities, we investigated several samples of soil, sludge, and sewage waste. A total of 168 strains were isolated from a 1-year-old sludge sample collected from a wastewater treatment plant. Two of these isolates were found to be markedly different from the other isolates and from previously described genera in their chemotaxonomic and their physiological features. In this paper these two strains are characterized phenotypically and phylogenetically. Below we propose the creation of a new genus, the genus Janibacter gen. nov., with one species, Janibacter limosus sp. nov., for these organisms. MATERIALS AND METHODSBacterial strains and cultural conditions. Strains HKI 83T (T = type strain) and HKI 84 were isolated from a 1-year-old sludge sample from the wastewater treatment plant near Jena, Thuringia, Germany, by the dilution plate technique on plate count agar (Difco Laboratories, Detroit, Mich.). General laboratory cultivation was performed at 28°C on solid rich medium (R medium) or in liquid R medium (43), which contained 1% (wtivol) Bacto Peptone (Difco), 0.5% (wt/vol) yeast extract, 0.5% (wt/vol) Casamino Acids, 0.2% (wthol) meat extract, 0.5% (wt/vol) malt extract, 0.2% (wtivol) glycerol. 0.1% (wt/vol) MgSO, -7H,O, and 0.005% (wt/vol) Tween 80 (pH 7.2). To determine the cellular fatty acids, strains were cultivated for 24 h in liquid tryptic soy broth (Difco) at 28°C.Morphological and physiological characteristics. Colony morphology on R medium and cell morphology at different ages were determined by stereomicroscopy and phase-contrast microscopy (Olympus, Tokyo, Japan). Nitrate reductase activity, urease activity, indole production, methyl red and Voges-Proskauer reactions, hydrogen sulfide production, and hydrolysis of esculin and Tween 80 were determined as described by Lanyi (...

A novel actinomycete was isolated from compost soil and was studied taxonomically and phylogenetically. Cells of this organism were gram positive, not acid fast, nonmotile, nonsporulating, irregular coccoid to short rod shaped, and microaerophilic. The cell wall peptidoglycan contained lysine and was cross-linked via an L-Lys+L-Ser+D-Asp interpeptide bridge. The major menaquinone was MK-8(H4). The polar lipids were phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and two unknown phospholipids. Mycolic acids were absent. The cellular fatty acid profile was complex, with large amounts of saturated and monounsaturated straight-chain acids and smaller amounts of is0 and anteiso branched-chain acids. The G+C content of the DNA was 66 mol%. Comparative 16s ribosomal DNA studies revealed that strain HKI 0089T represents a novel lineage within Actinobacteria (32) distinct from all previously described genera and most closely related to members of the genera Kytococcus, Demcoccus, and Dermatophilus of the family Dermatophihceae. On the basis of our results, we suggest that strain HKI 0089 should be classified in a new genus and species, for which we propose the name Demetria terragena. The type strain and the only strain of the genus and species is HKI 0089 (DSM 11295).In a program aimed at isolating rare or novel actinomycetes as a potential resource of bioactive secondary metabolites, isolates were studied by morphological, physiological, and chemotaxonomic methods. It is generally accepted that the results of chemotaxonomic analyses of cellular compounds are extremely useful for delimiting genera within the order Actinomycetales (6, 30). In 115 of 900 isolates of actinomycetes originating from 33 soil samples from different geographic regions, lysine was found to be the diagnostic diamino acid in the peptidoglycan. Most of these strains could be identified as members of the genera Arthrobacter, Kocuria, Micrococcus, Nesterenkonia, Oerskovia, Promicromonospora, and Microbacterium. We focused our interest on two of these isolates commonly containing lysine and having MK-8(H4) as the main menaquinone but differing remarkably from each other by morphological, physiological, and further biochemical properties. One of these isolates from a sample of soda soil has been recently described as a member of the new genus and species Bogoriella caseilytica (13). In this paper, we describe the taxonomic and phylogenetic characterization of the second isolate, HKI 0089T, with the combination of the cell wall diamino acid lysine and the menaquinone MK-8 (H4). On the basis of our results, we suggest that this strain should be assigned to a new genus and species. The name Demetria terragena is proposed for this organism, which has been deposited in the German Collection of Microorganisms and Cell Cultures as strain DSM 11295T. Strain HKI 0089 is the type strain and the only strain of D. terragena. MATERIALS AND METHODSBacterial strain and cultural conditions. Strain HKI 0089T was isolated fr...

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