T w o actinomycete strains, DF-28 and DF-32T, were isolated from soil samples collected in a deciduous dipterocarp forest in Thailand. They produced longitudinally paired spores on the tips of short sporophores alternately branched from aerial hyphae, and the chemotaxonomic properties of the isolates were the same as those of members of the family Streptosporangiaceae. These phenotypic properties, together with the results of a phylogenetic analysis based on 16s rRNA gene sequences, indicated that these isolates should be assigned to the genus Microbispora. The two isolates showed more than 93% DNA relatedness to each other, but their relatedness to any previously described species of the genus Microbispora was only 4 5 % or less. They were distinguishable from previously described Microbispora spp. b y a combination of physiological and biochemical properties. Therefore, a new species is proposed for these strains, under the name Microbispora corallina sp. nov. The type strain is strain DF-32T ( = JCM 10267T).
The description of the genus Kineosporiu is amended after chemotaxonomic and morphological studies of the type strain of the type species, Kineosporiu uurantiucu JCM 3230. This organism yielded both LL-and rneso-diaminopimelic acids, which suggested that the former is present in the mycelium and the latter is present in the spores. There was no characteristic sugar pattern. A diagnostic phospholipid was phosphatidylcholine, and a major menaquinone component was MK-9(H4). No iso/anteiso branched fatty acids and no mycolic acids were observed. Colonies on agar lacked aerial mycelia, formed central projections including spores, and were occasionally accompanied by bunches of spore clusters in the agar. Spores were catenated or were located singly or aggregately at the tips of the vegetative hyphae. Our data indicate that the strain representative of the genus Kineosporiu shows some similarity to the spore dome actinomycetes described by Willoughby and by Makkar and Cross.The name Kineosporia aurantiaca was proposed by Pagani and Parenti in 1978 (11) for an actinomycete that lacked aerial mycelia and bore numerous sporangia, each of which contained a single zoospore, on the substrate mycelia. Analyses of the cellular components in the original description showed the presence of glycine and LL-diaminopimelic acid (A,pm) in the cell walls and arabinose, galactose, and xylose in the whole organism. Pagani and Parenti emphasized the structure of the sporangium of their strain, compared with the sporangia of the other sporangium-forming actinomycetes, and consequently placed it in the new genus Kineosporia .Recently, Hasegawa et al. (4) reported that whole cells of K . aurantiaca contain two isomers of A,pm, the LL and meso forms, but lack arabinose and xylose. Our analyses agree with the analyses of these authors. In addition, we observed that the spores are catenated or form aggregately at the tips of hyphae.Therefore, the description of the genus Kineosporia should be revised, and further studies on K . aurantiaca should be undertaken. We studied this organism to gain a better understanding of the taxonomy of the monospecific genus Kineosporia . MATERIALS AND METHODSStrain used, cultivation, and spore collection. K . aurantiaca JCM 3230T (= KCC A-0320T = Ah0312 Pagani and ParentiT) (T = type strain) was cultivated in yeast extract-glucose broth containing 10 g of yeast extract (Difco Laboratories, Detroit, Mich.) and 10 g of glucose in 1,000 ml of distilled water (pH 7.2) at 28°C for 5 to 6 days and then harvested by centrifugation. The biomass consisted of mycelial mats and numerous zoospores; this preparation was designated whole cultured organism.Spores were collected from a spread culture grown on a dilute yeast extract-starch agar plate containing 0.5 g of yeast extract (Daigo Eiyo, Osaka, Japan), 2.5 g of soluble starch, and 15 g of agar in 1,000 ml of distilled water (pH 7.3) at 25°C for 6 days. The spread culture was dipped in distilled water, and the surface was lightly scratched to promote the release of m...
ORCID ID: 0000-0001-5449-6492 (H.S.).Cytokinins (CKs), a class of phytohormones that regulate plant growth and development, are also synthesized by some phytopathogens to disrupt the hormonal balance and to facilitate niche establishment in their hosts. Rhodococcus fascians harbors the fasciation (fas) locus, an operon encoding several genes homologous to CK biosynthesis and metabolism. This pathogen causes unique leafy gall symptoms reminiscent of CK overproduction; however, bacterial CKs have not been clearly correlated with the severe symptoms, and no virulence-associated unique CKs or analogs have been identified. Here, we report the identification of monomethylated MeCKs were recognized by a CK receptor and up-regulated type-A ARABIDOPSIS THALIANA RESPONSE REGULATOR genes. Treatment with MeCKs inhibited root growth, a hallmark of CK action, whereas the receptor mutant was insensitive. MeCKs were retained longer in planta than canonical CKs and were poor substrates for a CK oxidase/ dehydrogenase, suggesting enhanced biological stability. MeCKs were synthesized by S-adenosyl methionine-dependent methyltransferases (MT1 and MT2) that are present upstream of the fas genes. The best substrate for methylation was isopentenyl diphosphate. MT1 and MT2 catalyzed distinct methylation reactions; only the MT2 product was used by FAS4 to synthesize monomethylated N 6 -(Δ 2 -isopentenyl)adenine. The MT1 product was dimethylated by MT2 and used as a substrate by FAS4 to produce dimethylated N 6 -(Δ 2 -isopentenyl)adenine. Chemically synthesized MeCKs were comparable in activity. Our results strongly suggest that MeCKs function as CK mimics and play a role in this plant-pathogen interaction.
Actinomycetes are one of the main microbial groups that produce bioactive compounds used as antibiotics. Although bacteria, mold and yeast have frequently been found in bees, the presence of actinomycetes in bee hives had not been previously identified or reported. The aim of our research was to focus on the diversity of actinomycetes in bee hives in Thailand. Bees, brood cells and hive materials were collected from apiaries and natural sources. Thirty-two isolates of actinomycetes were isolated and identified using morphological, physiological, chemical and molecular characterization. Most of the isolates belonged to the genus Streptomyces. Some less frequent isolates were classified in the genera Nonomuraea, Nocardiopsis and Actinomadura.
were studied to establish their taxonomic status. Well-developed fragmenting vegetative mycelium was observed. The chemotype was type IVA containing rneso-diaminopimelic acid, arabinose, and galactose. The predominant isoprenoid quinone was MK-8(H4), and mycolic acids were present. These morphological and chemical properties are characteristic of the genus Nocurdiu. The physiological and biochemical characteristics were most similar to those of Nocurdiu usteroides; however, these organisms were different in their decomposition of urea, growth temperature, utilization of nitrogen sources, survival at 50°C for 8 h, mycolic and fatty acid profiles, and deoxyribonucleic acid-deoxyribonucleic acid hybridization characteristics. Therefore, we propose a new species for these strains, Nocurdiu seriolae. The type strain is strain JCM 3360.A disease caused by actinomycetes in cultured fishes occurred first in rudderfishes (Seriola quinqueradiata and Seriola purpurascens) in Mie Prefecture, Japan, in 1967 (2, 13) and then spread to fish farms in the western district of Japan. This disease is characterized by the formation of abscesses in the epidermis and of tubercles in gills, kidneys, and spleens (13,15,17, 18). In 1968, the causative organisms were initially isolated, and their morphological, physiological, and biochemical characteristics were examined by Kariya et al. (13). Although these authors suggested that the strains were related to Nocardia asteroides, they proposed a new species, "Nocardia kampachi," for these organisms because of differences in some physiological and biochemical characteristics. However, morphology was the sole characteristic used for assignment of these strains to the genus Nocardia, and the description of " N . kampachi" lacked designation of a type strain. This name has never been validated, and original strains are not available anymore. Later, in 1973 and1974, Kusuda and Taki (17) and Kusuda et al. (18) isolated bacteria from infected yellowtails and identified them as " N . kampachi."We studied one of the strains of Kusuda (17) and four strains newly isolated from infected fishes (yellowtails [S. quinqueradiata] and a Japanese flounder [Paralichthys olivaceus]) to establish the taxonomic status of these strains. Based on morphological and chemical properties, we assigned the isolates to the genus Nocardia, and we propose a new species, Nocardia seriolae, for them on the basis of deoxyribonucleic acid (DNA)-DNA hybridization results and mycolic and fatty acid profiles in addition to physiological and biochemical characteristics. MATERIALS AND METHODSBacterial strains. In this study we used five strains isolated from cultured fishes from various fish farms in Japan and, for comparison, some strains of N . asteroides and related strains (Table 1).Morphology. The morphology of the isolates was studied by growing the strains on dilute yeast extract-malt extract agar (ISP medium no. 2 diluted to a 1/10 concentration) at 28°C for 5 days. A sample for electron microscopy was * Corresponding au...
To resolve relationships between members of the family Thermomonosporaceae, phylogenetic analyses using three sets of nucleotide sequences from 16S rDNA, 23S rDNA and the 16S-23S internal transcribed spacer (ITS) were carried out. Nearly all species of the family were included in this study. On the basis of congruous phylogenetic results and chemotaxonomic data, the following proposals are made. First, Actinomadura libanotica, Actinomadura aurantiaca, Actinomadura glomerata and Actinomadura longicatena are transferred to the genus Actinocorallia as Actinocorallia libanotica comb. nov., Actinocorallia aurantiaca comb. nov., Actinocorallia glomerata comb. nov. and Actinocorallia longicatena comb. nov., respectively. All the species of this genus are phylogenetically coherent and of phospholipid type PII (presence of phosphatidylethanolamine), distinguishing them from other Actinomadura species that are of phospholipid type PI (absence of diagnostic phospholipids). Second, Excellospora viridilutea is transferred to the genus Actinomadura as Actinomadura viridilutea comb. nov. As a result of the proposed transfers, the family Thermomonosporaceae now contains four genera Thermomonospora, Actinomadura, Actinocorallia and Spirillospora. The genus Actinocorallia and family Thermomonosporaceae are redescribed.
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