• Journal of Microbiology
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• v.44 no.6
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• pp.600-606
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• 2006

Spore forming actinobacteria (sporoactinobacteria) isolated from soils with an acidic pH in Pinus thunbergii forests and coal mine waste were subjected to taxonomic characterization. For the isolation of acidophilic actinobacteria, acidified starch casein agar (pH adjusted to 4-5) was used. The numbers of actinobacteria growing in acidic media were between $3.2{\times}10^4$ and $8.0{\times}10^6$ CFU/g soil. Forty three acidophilic actinobacterial strains were isolated and their 16S rDNA sequences were determined. The isolates were divided into eight distinctive phylogenetic clusters within the variation encompassed by the family Streptomycetaceae. Four clusters among them were assigned to the genus Streptacidiphilus, whereas the remaining four were assigned to Streptomyces. The clusters belonging to either Streptomyces or Streptacidiphilus did not form a monophyletic clade. The growth pH profiles indicated that the representative isolates grew best between pH 5 and 6. It is evident from this study that acidity has played a critical role in the differentiation of the family Streptomycetaceae, and also that different mechanisms might have resulted in the evolution of two groups, Streptacidiphilus (strict acidophiles) and neutrotolerant acidophilic Streptomyces. The effect of geographic separation was clearly seen among the Streptacidiphilus isolates, which may be a key factor in speciation of the genus.

• Microbiology and Biotechnology Letters
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• v.46 no.1
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• pp.68-76
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• 2018

Actinobacterial strains isolated from Cow feces were studied for their antifungal attributes against phytopathogens and industrially important enzymes. A total of 30 Actinobacterial strains were obtained from 10 samples of cow feces. All the strains were belonging to the genera Streptomyces on the basis of morphological and chemotaxonomic analysis. During preliminary screening, out of 30 strains, 15 strains (50%) showed antifungal activity against five fungal phytopathogens including Aspergillus niger, Fusarium solani, Fusarium oxysporum, Macrophomina phaseolina and Rhizoctonia solani. While, isolate GBTCF-26 was found to be most active against R. solani with 62.2% inhibition of fungal mycelium, GBTCF-09 was prominent against F. solani and F. oxysporum with percent inhibition of 61.1% and 58.8%, respectively. Out of 30 strains, 19 (63.3%), 16 (53.3%), 11 (36.7%), 10 (33.3%), 4 (13.3%) and 8 (26.7%) strains were producing amylase, caseinase, gelatinase, lipase, chitinase and cellulose, respectively. The selected strains, GBTCF-09, GBTCF-21 and GBTCF-26, were identified as Streptomyces sp. on the basis of their 16S rDNA sequence. The study supports the idea that the Actinobacteria from unique niches (Cow feces) possess the production potential of industrially important enzymes including bioactive molecules.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.275-283
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• 2012

Culture-dependent RFLP and culture-independent DGGE were employed to investigate the bacterial community associated with the marine sponge Asteropus simplex collected from Jeju Island. A total of 120 bacterial strains associated with the sponge were cultivated using modified Zobell and MA media. PCR amplicons of the 16S rDNA from the bacterial strains were digested with the restriction enzymes HaeIII and MspI, and then assigned into different groups according to their restriction patterns. The 16S rDNA sequences derived from RFLP patterns showed more than 94% similarities compared with known bacterial species, and the isolates belonged to five phyla, Alphaproteobacteria, Gammaproteobacteria Actinobacteria, Bacteroidetes, and Firmicutes, of which Gammaproteobacteria was dominant. DGGE fingerprinting of 16S rDNAs amplified from the sponge-derived total gDNA showed 12 DGGE bands, and their sequences showed more than 90% similarities compared with available sequences. The sequences derived from DGGE bands revealed high similarity with the uncultured bacterial clones. DGGE revealed that bacterial community consisted of seven phyla, including Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteira, Chloroflexi, and Nitrospira. Alphaproteobacteria, Gammaproteobacteria, and Actinobacteria were commonly found in bacteria associated with A. simplex by both RFLP and DGGE methods, however, overall bacterial community in the sponge differed depending on the analysis methods. Sponge showed more various bacterial community structures in culture-independent method than in culture-dependent method.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.124-128
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• 2015

Large patch, caused by Rhizoctonia solani AG2-2 IV, is a soil-born disease that is the most important of warm season turfgrass such as zoysia and Bermuda grass. This study was conducted to analysis of the soil microbial community structure on large patch. Center of the large patch (CLC), edge (CLE) and healthy (CLH) part of microbial communities were examined using metagenomics in Phylum level. Distribution trends of the rhizosphere microorganisms were similar to the order Proteobacteria, Acidobacteria, Chloroflexi, Firmicutes, Planctomycetes, Gemmatimonadetes, Nitrospira, Cyanobactria and Verrucomicrobia in soil collections. Contrastively Actinobacteria was more 56% abundant in healthy part soil (16%) than in the center (9.28%) or edge (10.84%) parts. Taxonomic distributions were compared among the CLC, CLE and CLH, total 6,948 OTUs were detected in the CLC, 6,505 OTUs for the CLE and 5,537 OTUs were detected in the CLE. Distributions of Actinobacteria OTUs were appeared 615 OTUs in the CLC, 709 OTUs in the CLE and 891 OTUs in the CLH. Among Actinobacteria, 382 OTUs were overlapped in the all soils. Not matched OTUs of CLH (286 OTUs) was detected 23 times higher than CLC (91 OTUs) and CLE (126 OTUs).

• Korean Journal of Environmental Biology
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• v.29 no.3
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• pp.126-137
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• 2011

Although Sumunmulbangdui wetland at the Halla Mountain in Jeju Island, a kind of montane wetlands, has been considered to bear high biodiversity, no study has been reported on the bacterial diversity. In this study, soil and water samples were collected from the wetland in order to isolate novel bacterial species. Bacterial strains belonging to the phyla Bacteroidetes, Firmicutes, and Actinobacteria were isolated after spreading soil and water samples onto solid agar media. The 16S rRNA gene sequences of the strains assigned to the three phyla were compared to those of type strains of the species in the phyla. The strains that showed less than 98.7% 16S rRNA gene sequence similarity to the validly published species were considered to be novel species candidates. A total of 32 strains were regarded as novel species candidates in the phyla Bacteroidetes, Firmicutes, and Actinobacteria. Diversity of novel species candidates was very low; the candidates were confined to only few genera. In the Bacteroidetes, 13 novel candidate species were affiliated with the genera Mucilaginibacter, Sphingobacterium, Pedobacter, Flavobacterium, and Chryseobacterium. A total of 13 novel candidate species that assigned to the genera Paenibacillus Lysinibacillus, and Bacillus were identified in the phylum Firmicutes. Only two candidate species that belonged to the genera Mycobacterium and Nocardia were excavated in the Actinobacteria. Cultural, physiological, and chemotaxonomic characteristics have been determined for the novel species candidates, and the characteristics are described in this study.

• Journal of Species Research
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• v.8 no.2
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• pp.247-248
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• 2019

• Journal of Microbiology
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• v.45 no.6
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• pp.479-484
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• 2007

Bacterial communities at 10 cm, 100 cm, and 200 cm depths in a 100-year-old lead-zinc tailing heap were evaluated by constructing 16S rRNA gene libraries. In total, 98 operational taxonomic units (OTUs) were identified from 193 clones at a 3% sequence difference level. The OTU number and species richness decreased with the depth. Species composition was significantly different between the three libraries. Fifty-seven percent of the examined clones were Acidobacteria and 27% belonged to Proteobacteria. Other sequences included Chloroflexi, Firmicutes, Chlamydiae, Actinobacteria, Gemmatimonadetes, Nitrospira, and three unclassified OTUs. Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Firmicutes, and Actinobacteria were mainly distributed in the rhizosphere of naturally colonizing plants; however, Deltaproteobacteria, Acidobacteria, and Chloroflexi tended to inhabit the deeper tailings (below the 100 cm-depth).

• Journal of Microbiology
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• v.45 no.4
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• pp.367-370
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• 2007

Microbial diversity in decaying maize stalk was characterized by constructing and analyzing rRNA gene clone library. Total 47 OTUs were obtained from 82 bacterial clones, including Proteobacteria (64.6%), Actinobacteria (30.5%), Bacteroidetes (2.4%) and Firmicutes (2.4%). Most proteobacterial clones were members of Rhizobium, Pseudomonas and Stenotrophomonas. Eighty-four percent of Actinobacteria was related to Microbacterium. Only 14 OTUs were identified from 124 fungal clones, including Ascomycota (88%) and Basidiomycota (12%). Sixty percent of Ascomycota were members of Eupenicillium and Paecilomyces but all Basidiomycota were close to Kurtzmanomyces nectairei.

• Journal of Microbiology and Biotechnology
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• v.28 no.9
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• pp.1517-1526
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• 2018

Investigating bacterial diversity and its metabolic capabilities is crucial for interpreting the ecological patterns in a desert environment and assessing the presence of exploitable microbial resources. In this study, we evaluated the spatial heterogeneity of physicochemical parameters, soil bacterial diversity and metabolic adaptation at meter scale. Soil samples were collected from two quadrats of a desert (Thar Desert, India) with a hot, arid climate, very little rainfall and extreme temperatures. Analysis of physico-chemical parameters and subsequent variance analysis (p-values < 0.05) revealed that sulfate, potassium and magnesium ions were the most variable between the quadrats. Microbial diversity of the two quadrats was studied using Illumina bar-coded sequencing by targeting V3-V4 regions of 16S rDNA. As for the results, 702504 high-quality sequence reads, assigned to 173 operational taxonomic units (OTUs) at species level, were examined. The most abundant phyla in both quadrats were Actinobacteria (38.72%), Proteobacteria (32.94%), and Acidobacteria (9.24%). At genus level, Gaiella represented highest prevalence, followed by Streptomyces, Solirubrobacter, Aciditerrimonas, Geminicoccus, Geodermatophilus, Microvirga, and Rubrobacter. Between the quadrats, significant difference (p-values < 0.05) was found in the abundance of Aciditerrimonas, Geodermatophilus, Geminicoccus, Ilumatobacter, Marmoricola, Nakamurella, and Solirubrobacter. Metabolic functional mapping revealed diverse biological activities, and was significantly correlated with physicochemical parameters. The results revealed spatial variation of ions, microbial abundance and functional attributes in the studied quadrats, and patchy nature in local scale. Interestingly, abundance of the biotechnologically important phylum Actinobacteria, with large proposition of unclassified species in the desert, suggested that this arid environment is a promising site for bioprospection.

• Journal of Species Research
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• v.5 no.2
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• pp.223-234
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• 2016

As a subset work for the collection of indigenous prokaryotic species in Korea, 38 actinobacterial strains were isolated from various environmental samples obtained from plant root, ginseng cultivating soil, mud flat, freshwater and seawater. Each strain showed higher 16S rRNA gene sequence similarity (>99.1%) and formed a robust phylogenetic clade with closest actinobacterial species which were defined and validated with nomenclature, already. There is no official description on these 38 actinobacterial species in Korea. Consequently, unrecorded 37 species of 24 genera in the 12 families belonging to the order Actinomycetales of the phylum Actinobacteria were found in Korea. Morphological properties, basic biochemical characteristics, isolation source and strain IDs are described in the species descriptions.