Journal of Microbiology

Journal Article

Antifungal activity of 3-acetylbenzamide produced by actinomycete WA23-4-4 from the intestinal tract of Periplaneta americana: Xia Fang , Juan Shen , Jie Wang , Zhi-li Chen , Pei-bin lin , Zhi-yu Chen , Lin-yan Liu , Huan-xiong Zeng , Xiao-bao Jin; J. Microbiol. 2018;56(7):516-523. Published online June 28, 2018; DOI: https://doi.org/10.1007/s12275-018-7510-z

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Abstract: Actinomycetes are well-known for producing numerous bioactive secondary metabolites. In this study, primary screening by antifungal activity assay found one actinomycete strain WA23-4-4 isolated from the intestinal tract of Periplaneta americana that exhibited broad spectrum antifungal activity. 16S rDNA gene analysis of strain WA23-4-4 revealed close similarity to Streptomyces nogalater (AB045886) with 86.6% sequence similarity. Strain WA23-4-4 was considered as a novel Streptomyces and the 16s rDNA sequence has been submitted to GenBank (accession no. KX291006). The maximum antifungal activity of WA23-4-4 was achieved when culture conditions were optimized to pH 8.0, with 12% inoculum concentration and 210 ml ISP2 medium, which remained stable between the 5th and the 9th day. 3-Acetyl benzoyl amide was isolated by ethyl acetate extraction of WA23- 4-4 fermentation broth, and its molecular formula was determined as C9H9NO2 based on MS, IR, 1H, and 13C NMR analyses. The compound showed significant antifungal activity against Candida albicans ATCC 10231 (MIC: 31.25 μg/ml) and Aspergillus niger ATCC 16404 (MIC: 31.25 μg/ml). However, the compound had higher MIC values against Trichophyton rubrum ATCC 60836 (MIC: 500 μg/ml) and Aspergillus fumigatus ATCC 96918 (MIC: 1,000 μg/ml). SEM analysis showed damage to the cell membrane of Candida albicans ATCC 10231 and to the mycelium of Aspergillus niger ATCC 16404 after being treatment with 3-acetyl benzoyl amide. In conclusion, this is the first time that 3-acetyl benzoyl amide has been identified from an actinomycete and this compound exhibited antifungal activity against Candida albicans ATCC 10231 and Aspergillus niger ATCC 16404.

Research Support, Non-U.S. Gov't

Stratified Distribution of Nutrients and Extremophile Biota within Freshwater Ice Covering the Surface of Lake Baikal: Nina A. Bondarenko , Olga I. Belykh , Ludmila P. Golobokova , Olga V. Artemyeva , Natalia F. Logacheva , Irina V. Tikhonova , Irina A. Lipko , Tatyana Ya. Kostornova , Valentina V. Parfenova , Tamara V. Khodzher , Young-Gun Zo; J. Microbiol. 2012;50(1):8-16. Published online February 27, 2012; DOI: https://doi.org/10.1007/s12275-012-1251-1

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Abstract: Biological entities and gradients of selected chemicals within the seemingly barren ice layers covering Lake Baikal were investigated. Ice cores 40–68 cm long were obtained from inshore and offshore sites of Southern Lake Baikal during the cold period of a year (March-April) in 2007 and 2008. In microscopic observations of the melted ice, both algae and bacteria were found in considerable numbers (>103 cells/L and >104 cells/ml, respectively). Among all organisms found, diatom was generally the most predominant taxon in the ice. Interestingly, both planktonic and benthic algae were present in considerable numbers (2–4×104 cells/L). Dominant phototrophic picoplankton were comprised of small green algae of various taxa and cyanobacteria of Synechococcus and Cyanobium. The bacterial community consisted mostly of short rod and cocci cells, either freeliving or aggregated. Large numbers of yeast-like cells and actinomycete mycelium were also observed. Concentrations of silica, phosphorus, and nitrate were low by an order of magnitude where biota was abundant. The profile of the ice could be interpreted as vertical stratification of nutrients and biomass due to biological activities. Therefore, the organisms in the ice were regarded to maintain high activity while thriving under freezing conditions. Based on the results, it was concluded that the freshwater ice covering the surface of Lake Baikal is considerably populated by extremophilic microorganisms that actively metabolize and form a detritus food chain in the unique large freshwater ecosystem of Lake Baikal.

Numerical classification of actinomycetes isolated from volcanic soil: Kim, Seung Bum , Lee, Soon Dong , Kim, Seon Young , Oh, Hyung Myung , Kang, Sa Ouk , Hah, Yung Chil; J. Microbiol. 1996;34(2):105-116.

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Abstract: Of actinomycetes isolated from volcanic compost soils, 115 representative strains which showed distinctive morphologicla features were numerically classified, compared with reference strains of Streptomyces. One hundred and twenty unit characters were tested and the average probability of error was 4.27%. The cluster analysis resulted in two groups: group A included strains of actinomycetes except streptomycetes. Group A was divided into 2 major clusters (over 5 strains), 10-diaminopimelic acid. Group B was divided into 5 clusters, of which 4 clusters contained mesodiminopimelic acid and 1 cluster LL-diaminopimelic acid. The major clusters of group A showed higher abilities of substrate utilization and degradation, and higher resistance to inhibitors, whereas the minor and single member clusters of group A showed relatively higher antimicrobial activities. On the other hand, all clusters of group B showed relatively lower abilities of substrate utilization and degradation and lower resistance to inhibitors.

Isolation and Characterization of Fatty Acid Derivatives from an Actinomycetes and Examination of the Effects on Activities of Phospholipase C and Protein Kinase C: Ko, Hack Ryong , Kim, Bo Yeon , Lee, Hyun Sun , Kang, Dae Ook , Ryu, Sung Ho , Suh, Pann Ghill , Mheen, Tae Ick , Ahnm Jong Seog; J. Microbiol. 1998;36(4):316-321.

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Abstract: In our screening to search inhibitors of phosphoinositide(PI)-specific phospholipase C (PI-PLC), two inhibitors, MT965-A and-B were isolated from a culture broth of an actinomycetes. MT965-A and-B were identified as fatty acid deribatives, 14-methylpentadecanoic acid and 16-methyllinoleic acid methyl ester, respectively, based on the spectral data including NMR and MS. Both inhibitors directly inhibited not only in vitro PLCγ1 activity but also the platelet-derived growth factor(PDGF)-induced inositol phosphates(IPt) formation in NIH 3T3γ1 cells ocerexpressing PLCγ1. However, the inhibitors enhanced in vitro protein kinase C (PKC) activity. On examination of the effects of various fatty acids(FAs) on activities of PLC, PKC, and PDGF-induced IPt formation, the unsaturated FAs(UFAs) showed the same activities like the inhibitors, but the saturated FAs(SFAs) did not show similar activities. It was inferred that the chain length, degree of unsaturation, methyl esterification, branching with a methyl group, and cis-configuration were important for their activity.

Diversity of Actinomycetes Antagonistic to Plant pathogenic Fungi in Cave and Sea-Mud Soils of Korea: Kim, Beom Seok , Lee, Jung Yeop , Hwang, Byung Kook; J. Microbiol. 1998;36(2):86-92.

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Abstract: To isolate actinomycetes antagonistic to plant pathogenic fungi, soil samples were collected from caves and sea-shores in Korea. The 481 actinomycetes were isolated from the soil samples examined, representing more than 50% of total counts. Nocardioform actinomycetes were rare actinomycete genera. Saccharomonospora could be isolated only in 3 cave soil samples from Cheondong, Kosoo, and Nodong, but was not present in all the sea-mud soils examined. Dactylosporangium, Saccharomonospora, and Streptosporangium were very rare in both cave and sea-mud soils. The 311 of 481 actinomycete isolates inhibited the mycelial growth of at least one of the tested fungi. The isolation rates of antagonistic actinomycetes from cave soils ranged from 45.7% to 78%, and those of sea-mud soils were from 59.1% to 66.0%. The 96 of 136 Streptomyces isolates from cave soils, and 93 of 133 isolates from sea-mud soils showed antifungal activity. The proportion of antagonistic isolates of Nocardioform actinomycetes (13.6%) was lower than that of other genera. Among the actinomycetes from sea-mud soils, Dactylosporangium and Streptosporangium had highest proportions of actinomycete antagonists of 85.7% and 80%, respectively. The isolation rate of Nocardioform antagonist from sea-mud soils was 11.1% similar in the cabve soils. Streptomyces strains showed higher antifungal activities against plant pathogenic fungi than did other rare actinomycete antagonists.

Effects of Selected Environmental Conditions on Biomass and Geosmin Production by Streptomyces halstedii: Kevin K. Schrader , Willard T. Blevins; J. Microbiol. 1999;37(3):159-167.

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Abstract: The effects of bicarbonate concentration, atmospheric carbon dioxide level, and reduced atmospheric oxygen on biomass and geosmin production and geosmin/biomass (G/B) values for Streptomyces halstedii, a producer of the off-flavor compound geosmin, were determined. In addition, a study was performed to determined possible synergistic relationships between a cyanobacterium, Oscillatoria tenuis UTEX #1566, and S. halstedii in the enhancement of actinomycete growth and/or geosmin production. These studies took into consideration those conditions that can occur during cyanobacterial bloom die-offs. Increasing bicarbonate concentration caused slight decreases in geosmin production and G/B for S. halstedii. Increasing atmospheric oxygen promoted geosmin production and G/B while lower oxygen levels resulted in a decrease in geosmin production and G/B by S. halstedii. Biomass production by S. halstedii was adversely affected by reduced oxygen levels while changes in bicarbonate concentration and atmospheric carbon dioxdie levels had little effect on biomass production. Sonicated cells of O. tenuis UTEX #1566 promoted biomass production by S. halstedii, and O. tenuis culture (cells and extracellular metabolites) and culture supernatnat (extracellular metabolites) each promoted geosmin and G/B yields for S. halstedii. In certain aquatic systems, environmental conditions resulting from cyanobacterial blooms and subsequent bloom die-offs could favor actinomycete growth and off-flavor compound production by certain actinomycetes.

An Improved Selective Isolation of Rare Actinomycetes from Forest Soil: Chi Nam Seong , Ji Heok Choi , Keun-Shik Baik; J. Microbiol. 2001;39(1):17-23.

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Abstract: Various pretreatment procedures and selective media were applied to assess the optimal conditions for the isolation of rare actinomycetes from soil. Pretreatment of wet-heating for 15 min at 70oC and phenol treatment of soil suspension were the most effective methods for the isolation of those microorganisms. Hair hydrolysate vitamin agar (HHVA) was the most suitable medium for the recovery of rare actinomycetes. Thirty-five rare actinomycete strains were chosen using selective isolation approaches, then morphological and chemical properties of the isolates were determined. The isolates belonged to one of the following genus, Micromonospora, Microbispora, Actinoplanes and Streptosporangium.

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