• Parasites, Hosts and Diseases
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• v.35 no.2
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• pp.127-134
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• 1997

Transmission electron microscopy of an ArGnthnmoebo isolate (KA/LS) from a contact lens case revealed bacterial endosymbionts within cytoplasm of the amoebae. The Acnnthamoebn isolate belonged to the morphological group ll. Based on the polymerase chain reaction (PCR) - restriction fragment leilgth polymorphism (RFLP) of 185 ribosomal RNA coding DNA (rDNA) , the isolate was identified as A. Iwnunensis. Strain typing by isoenzyme analysis using isorlectric focusing (IEF) and mitochondrial (Ent) DNA RFLP revealed that the isolate was closely related with KA/Ll , the most predominant type of isolates from contact lens storage casas, KA/E2, a clinical isolate, KA/W4, previou:fly reported to host endosymbionts. and L3a strains of A. Iwnunensis. The endosymbionts were similar to those of KA/W4 in a.jpects that they were randomly distributed in both trophozoites and cysts, and were rod-shaped bacteri3 measuring approximately 1.38 x 0.50 ㎛. But the number of endosymbionts per amoeba was significantly lower than that of KA/W4. They were neither limited by phagosomal membranes nor included in lacunae- like stnlcture.

• Mycobiology
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• v.29 no.1
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• pp.19-26
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• 2001

Defense mechanisms against anthracnose disease caused by Colletotrichum orbiculare on the leaf surface of cucumber plants after pre-treatment with plant growth promoting rhizobacteria(PGPR), amino salicylic acid(ASA) or C. orbiculare were compared using a fluorescence microscope. Induced systemic resistance was mediated by the pre-inoculation in the root system with PGPR strain Bacillus amylolquefaciens EXTN-1 that showed direct antifungal activity to C. gloeosporioides and C. orbiculare. Also, systemic acquired resistance was triggered by the pre-treatments on the bottom leaves with amino salicylic acid or conidial suspension of C. orbiculare. The protection values on the leaves expressing SAR were higher compared to those expressing ISR. After pre-inoculation with PGPR strains no change of the plants was found in phenotype, while necrosis or hypersensitive reaction(HR) was observed on the leaves of plants pre-treated with ASA or the pathogen. After challenge inoculation, inhibition of fungal growth was observed on the leaves expressing both ISR and SAR. HR was frequently observed at the penetration sites of both resistance-expressing leaves. Appressorium formation was dramatically reduced on the leaves of plants pre-treated with ASA, whereas EXTN-1 did not suppress the appressorium formation. ASA also more strongly inhibited the conidial germination than EXTN-1. Conversely, EXTN-1 significantly increased the frequency of callose formation at the penetration sites, but ASA did not. The defense mechanisms induced by C. orbiculare were similar to those by ASA. Based on these results it is suggested that resistance mechanisms on the leaf surface was different between on the cucumber leaves expressing ISR and SAR, resulting in the different protection values.

• Journal of Microbiology and Biotechnology
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• v.9 no.3
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• pp.282-291
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• 1999

Lactic acid bacteria were isolated from Kimchi and screened for bacteriocin. A total of 99 strains showed antimicrobial activity when grown on solid media, yet only 10 showed antimicrobial activity in liquid media. Strain H-559, identified as Lactococcus lactis subsp. lactis, exhibited the strongest inhibitory activity and was active against pathogenic bacteria including Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus as well as other lactic acid bacteria. The antimicrobial substance produced by L. lactis subsp. lactis H-559 was confirmed to be a bacteriocin by the treatment of $\alpha$-chymotrypsin, and protease type Ⅸ and ⅩIV. The bacteriocin activity remained stable between pH 2.0 and pH 11.0 and during heating for 10 min at $100^{\circ}C$. The bacteriocin production started in the exponential phase and stopped in the stationary phase. L. lactis subsp. lactis H-559 showed the highest bacteriocin activity at a culture temperature of $25^{\circ}C$, and an inverse relationship between the bacteriocin productivity and mean growth rate at different culture temperatures was observed. The mean growth rate and bacteriocin productivity of L. lactis subsp. lactis H-559 increased as the initial pH of the media increased.

• Weed & Turfgrass Science
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• v.6 no.2
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• pp.157-164
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• 2017

Functional microorganisms decompose various organic matter by enzyme activity and suppress plant disease caused by pathogen. This study was conducted to isolate and select functional microorganisms with protein or carbohydrate degradation activities and antagonistic activity against turfgrass fungal pathogens for eco-friendly turfgrass management in golf course from compost containing livestock manure of poultry or swine. Totally 68 isolates collected from livestock manure compost strains were isolated and tested for their activities of amylase, protease and lipase and antagonistic activities against Rhizoctonia solani AG2-2, R. solani AG1-1, and Sclerotinia homoeocarpa. Among the isolates, 34 strains were selected as functional microbes showing higher activities of amylase and protease. Three isolates of ASC-14, ASC-18, and ASC-35 among the 34 strains were selected as antifungal bacterial strains repressing the above 3 turfgrass fungal pathogens. Analysis results of 16s rRNA gene sequence and phylogenic cluster indicated that ASC-14 and ASC-18 belonged to Bacillus amyloliquefaciens, while ASC-35 was B. subtilis, respectively.

• Applied Biological Chemistry
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• v.34 no.4
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• pp.307-311
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• 1991

A moderate halophile, ES 10 which produces a high level of alkaline protease was isolated from the salted anchovies and indentified as a strain of Halomonas sp. The optimum growth of the Halomonas sp. was revealed in the presence of 2 M NaCl and its growth rate in the Temporary Synthetic Medium was increased by adding DL-alanine, but inhibited by adding L-proline. The concentration of $Na^+$, $K^+$ and $Mg^{2+}$ in the cell mass of the Halomonas sp. ES 10 was 5-, 25- and 35-fold higher by dry weight basis, respectively than those of B. subtilis or E. coli. Norberg and Hofsten medium with 1 M NaCl was selected as the best medium for producing high level of alkaline protease. The optimum temperature for the growth and protease production was equally $20^{\circ}C$.

• Journal of Species Research
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• v.9 no.4
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• pp.362-374
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• 2020

A total of 35 bacterial strains were isolated from various sediment samples. From 16S rRNA gene sequence similarities higher than 98.7% and the formation of a robust phylogenetic clade with the closest species, it was determined that each strain belonged to independent and predefined bacterial species. No previous official reports have described these 35 species in Korea. The unrecorded species were assigned to 6 phyla, 10 classes, 18 orders, 23 families, and 31 genera. At the genus level, the unrecorded species were affiliated with Terriglobus of the phylum Acidobacteria, as well as with Mycobacterium, Rhodococcus, Kineococcus, Phycicoccus, Agromyces, Cryobacterium, Microbacterium, and Arthrobacter; Catellatospora of the class Actinomycetia; Lacibacter of the class Chitinophagia; Algoriphagus and Flectobacillus of the class Cytophagia; Flavobacterium and Maribacter of the class Flavobacteriia; Bacillus, Cohnella, Fontibacillus, Paenibacillus, Lysynibacillus, and Paenisporosarcina of the class Bacilli; Bradyrhizobium, Gemmobacter, Loktanella, and Altererythrobacter of the class Alphaproteobacteria; Acidovorax of the class Betaproteobacteria; Aliiglaciecola, Cellvibrio, Arenimonas, and Lysobacter of class Gammaproteobacteria; and Roseimicrobium of the class Verrucomicrobia. The selected strains were subjected to further taxonomic characterization, including Gram reaction, cellular and colonial morphology, and biochemical properties. This paper provides detailed descriptions of the 35 previously unrecorded bacterial species.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2010.10a
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• pp.18-18
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• 2010

Molecular insights on the role of plant growth promoting rhizobacteria (PGPR) in potato tuberization are reported in the present study. The PGPRwere isolated from the soil collected from potato fields of Highland Agricultural Research Centre, Pyeongchang, Korea and they were identified to the genus level based on the 16S rRNA sequence analysis. These PGPR were heat-killed, filtered and the filtrates were addedindividually at a concentration of $10^7\;cfu\;mL^{-1}$ in MS (Murashige and Skoog's) medium supplemented with 7% (w/v) sucrose to study their influence on in vitro potato tuberization. Tuber initiation occurred early in untreated control, while tuber growth was pronounced in case of PGPR treatments. The control explants showed tuber formation as a result of sub-apical swelling of stolons while several sessile tubers formed directly in the axils of nodal cuttings in case of PGPR treatments, which is an indication of strong induction for tuberization. Theexplants cultured on MS medium supplemented with bacterial isolate 6 (Bacillus firmus strain 40) showed highest average tuber yield (Ca. 12.56 g per treatment) after 30 days of culture, which was 3 folds increase over the untreated control. A significant increase in lipoxygenase (LOX1) mRNA expression and activity of LOX enzyme were also detected in the tubers induced on PGPR treatments as compared to untreated control. This LOX expression level correlated with increased tuber growth and tuber yield. Further studies focused on the role of bacteria cell wall components, growth regulators and signal molecules released by PGPR are under investigation to elicit clues for PGPR-mediated signal pathway controlling potato tuberization.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.195-205
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• 2005

Objective & Methods: To evaluate the in vitro synergic effect of Eunkyo-san, a traditional poly-herbal formula used in the treatment of respiratory diseases in oriental medicine with quinolone antibiotics, represented by ciprofloxacin (CPFX), which was used in the minimal concentration (MIC), $MIC_{50}$ and $MIC_{90}$. of single use of quinolones in concomitant treatment with Eunkyo-san against 9 strain$ of gram positive bacteria. Results: In. the case of aerobic gram positive bacteria, the MIC, $MIC_{50}$ and $MIC_{90}$ against Staphylococcus aureus, Staphylococcus aureus smith, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae Type I, Type II and Type III were significantly decreased in concomitant treated groups with Eunkyo-san compared to those of single treated groups of CPFX, respectively. However, no significant changes were demonstrated against Bacillus subtilis and Enterococcus faecalis. Conclusion: The in vitro antibacterial activity of CPFX were increased against some strains of gram positive strains, especially, pneumococcus such as Staphylococcus and Streptococcus, by concomitant use of Eunkyo-san.

• Microbiology and Biotechnology Letters
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• v.39 no.3
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• pp.287-293
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• 2011

The purpose of this study was to isolate and characterize fungal deteriogens, which induce discoloration of the cement tunnel, and calcite forming bacteria (CFBs), which have antifungal activity against fungal deteriogens. Isolation of mold, bacteria and yeast was performed using several solid media and partially identified using internal transcribed spacer (ITS); 5.8S rRNA gene sequencing and 16s rDNA sequencing. A total of 19 microbial strains were identified with the most widely distributed fungal strain being Cladospirum sphaerospermum. In addition, five bacteria derived from the tunnel were identified as CFBs. Amongst the latter, Bacillus aryabhatti KNUC205 exhibited antifungal activity against Cladospirum sphaerospermum KNUC253 and Aspergillus niger KCTC6906 as concentrated filtered supernatants.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1235-1244
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• 2008

Indole-3-acetic acid (IAA) is produced commonly by plants and many bacteria, however, little is known about the genetic basis involving the key enzymes of IAA biosynthetic pathways from Bacillus spp. IAA intermediates from the Gram-positive spore-forming bacterium Paenibacillus polymyxa E681 were investigated, which showed the existence of only an indole-3-pyruvic acid (IPA) pathway for IAA biosynthesis from the bacterium. Four open reading frames (ORFs) encoding indole-3-pyruvate decarboxylase-like proteins and putative indole-3-pyruvate decarboxylase (IPDC), a key enzyme in the IPA synthetic pathway, were found on the genome sequence database of P. polymyxa and cloned in Escherichia coli DH5$\alpha$. One of the ORFs, PP2_01257, was assigned as probable indole-3-pyruvate decarboxylase. The ORF consisted of 1,743 nucleotides encoding 581 amino acids with a deduced molecular mass of 63,380 Da. Alignment studies of the deduced amino acid sequence of the ORF with known IPDC sequences revealed conservation of several amino acids in PP2_01257, essential for substrate and cofactor binding. Recombinant protein, gene product of the ORF PP2_01257 from P. polymyxa E681, was expressed in E. coli BL21 (DE3) as a glutathione S-transferase (GST)-fusion protein and purified to homogeneity using affinity chromatography. The molecular mass of the purified enzyme showed about 63 kDa, corresponding closely to the expected molecular mass of IPDC. The indole-3-pyruvate decarboxylase activity of the recombinant protein, detected by HPLC, using IPA substrate in the enzyme reaction confirmed the identity and functionality of the enzyme IPDC from the E681 strain.