• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.295-301
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• 2017

Botulinum neurotoxin (BoNT/A) is a neurotoxin that selectively attacks the peripheral cholinergic nerve endings. It is produced by Gram -positive, endospore-forming strict anaerobic bacteria, Clostridium botulinum. Since BoNT/A could be a biothreat agent, as well as a contaminator of food and water supplies, the development of sensitive assays for toxin detection and potent antitoxin for the treatment of intoxication is necessary. In this study, for the purpose of producing monoclonal antibodies (mAbs) that are capable of neutralizing Botulinum neurotoxin type A (BoNT/A), scFv (single-chain variable domain fragment) libraries from the rabbit antisera against BoNT/A was fused to a human IgG. The resulting recombinant scFvIgG antibody protein was expressed in stable cell lines and was purified using a protein A affinity chromatography. The efficacy of scFvIgG mAb was confirmed by ELISA and was evaluated for the neutralization of BoNT/A in vivo. Such an in vivo toxin neutralization assay was performed using mice. Although scFvIgG antibody proteins (10 ug) failed to fully protect the mice challenged with BoNT/A (100,000 $LD_{50}$), it significantly prolonged the survival time. These results suggest that scFvIgG mAb may be capable of neutralizing BoNT/A single-chain variable domain fragment.

• Journal of Life Science
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• v.27 no.6
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• pp.688-693
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• 2017

Antifungal bacterium against Colletotrichum coccodes causing black dot disease of potatoes and anthracnose of tomatoes was isolated from sewage sludge. The isolate showed a 99% sequence homology of partial 16S rRNA of Bacillus methylotrophicus CBMB205 and Bacillus amyloliquefaciens subsp. plantarum FZB42. The isolate was identified as Bacillus sp. SW29-2, using the neighbor-joining phylogenetic tree, BlastN sequence analysis, and morphological and cultural characteristics. Bacillus sp. SW29-2 is an aerobic, Gram-positive, endospore-forming bacterium, of which the morphological and physiological characteristics were the same as those of type strain B. lichniformis CBMB205, except for the cell growth of over 4% NaCl. The cell growth of the temperature and the initial pH of the medium was shown at $18-47^{\circ}C$ (opt. ca. $38^{\circ}C$) and 3-9 (opt. ca. 6.0), respectively. The inhibition size (diameter) of Bacillus sp. SW29-2 against four strains of C. coccodes ranged from 23 to 29 mm. Also, the isolate showed antifungal activity against penicillium rot-causing Penicillium expansum in apples. Thus far, any report on the antifungal activity of Baciilus spp. against C. coccodes has not been found. These results suggest that the Bacillus sp. SW29-2 isolate could be used as a possible biocontrol agent against C. coccodes, and further applied to other plant pathogenic fungi.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.32-40
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• 2009

To understand contribution of thermophilic microorganisms in decomposition of litter deposits on shore of lakes, we surveyed a lakeshore litter deposit for bacteria growing at $60^{\circ}C$. Ten thermophilic isolates were selected for in-depth characterization, based on their high capacity to degrade high molecular weight organic compounds. Based on phylogenetic analysis on their 16S rRNA gene sequences, all isolates were identified as Geobacillus. The optimal growth temperature and pH of the strains ranged $55{\sim}60^{\circ}C$ and 6.0${\sim}$8.0, respectively. Salinity was inhibitory to the growth of the isolates, showing marked decrease of growth rates at 3% salinity. Based on activities of hydrolytic enzymes and profiles of carbohydrate utilization (determined by API 50 CHB kit), three G. stearothermophilus strains showed patterns clearly distinctive from other isolates. Two G. kaustophilus strains also demonstrated distinctiveness in their metabolic pattern and ecological parameters. However, ecological and metabolic profiles of the other five isolates were more variable and showed some degree of digression from their phylogenetic classification. Therefore, it could be concluded that endospore-forming thermophilic bacteria in lakeshore litter deposits contribute to degradation of organic materials with diverse ecological niches while having successions similar to microbial flora in compost. We propose that the thermophilic isolates and/or their thermo-tolerant enzymes can be applied to industrial processes as appropriate mixtures.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.312-316
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• 2012

In order to understand the effect of hydrostatic pressure (HP) on Bacillus subtilis isolated from makgeolli, the survival of B. subtilis after HP treatment (400 MPa for 5 min) in various substrates including phosphate buffer, tryptone soya broth at pH 7 and 4, and makgeolli at pH 4 was evaluated depending on bacterial forms (spores and vegetative cells) and adaptation conditions ($25^{\circ}C$ for 3 h, or $10^{\circ}C$ for 24 h). Spores were generally resistant to HP (<1 log reduction) regardless of conditions. In contrast, vegetative cells were generally susceptible to HP (up to 3 log reduction-except makgeolli) and were more susceptible after 3 h at $25^{\circ}C$ compared to 24 h at $10^{\circ}C$. In vegetative cells inoculated makgeolli (7 log CFU/mL), the colonies were not detected after 24 h at $10^{\circ}C$. Consequently, B. subtilis in makgeolli easily existed as spores and the spores were resistant to HP. Results demonstrate that HP was more promising in the inactivation of vegetative cells.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.283-289
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• 2002

This study was performed to search for potential microorganism that has rapid fermenting and physiological function from anchovy sauce. We isolated three bacterial strains, JM-1, JM-2, and JM-3 with proteolytic and fibrinolytic activity from anchovy sauce. Among the 3 bacterial strains, JM-3 showed the strongest proteolytic and fibrinolytic activity. Bacterial strain JM-3 was gram-positive rod, motile and formed endospore. The 16S rRNA of bacterial strain JM-3 was amplified by PCR and then its sequence was determined by ABI 310 genetic analyzer. The 16S rRNA sequence of bacterial strain JM-3 was compared to BLAST DNA database and identified to Bacillus subtilis with 99% of homology. The optimum temperature, pH and NaCl concentration for growth of B. subtilis JM-3 were $40^{\circ}C$, 5.0 and 0%, respectively. The optimum temperature, pH and NaCl concentration for proteolytic and fibrinolytic enzyme production of B. subtilis JM-3 were same as optimum conditions for growth. At 20% of NaCl concentration which is common NaCl concentration of fish sauce, B. subtilis JM-3 showed about 60% of proteolytic and fibrinolytic activity of 0% NaCl concentration. From above results, we found that B. subtilis JM-3 will be able to used for starter of functional fish sauce.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.87-94
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• 2007

A bacterium which has high enzymatic activities such as amylase, cellulase and protease was isolated from Korean traditional soybean food, doenjang. The isolated bacterium was identified to Bacillus subtilis HS25 by the test of morphological and biochemical properties according to Bergey's Manual of Systematic Bacteriology and API 50 CHL kit, and by the 16S rDNA sequence. The isolated B. subtilis HS25 had a potent antibacterial activity against food born causative or pathogenic bacteria. B. subtilis HS25 is endospore forming cell and contained flagella and abundant viscous material at the out layer of cell wall. It was rod type bacterium $(0.5{\sim}0.8{\times}3{\sim}5{\mu}m)$ having biochemical characteristics such as gram staining(+), catalase(+), oxidase(-) and hydrolysis of esculin(+). The optimal medium compositions for production of antibacterial substance in the B. subtilis HS25 were 1% of soluble starch, 0.5% of yeast extract, 0.5% of peptone and 0.05% of MgCl$_2{\cdot}6H_{2}O$. The optimum temperature and pH of the growth of the B. subtilis HS25 was 35$^{\circ}C$ and pH 7.5, respectively. The antibacterial activity was more high in neutral to a little alkaline pH (6.5-10.5) than in acidic pH. The optimal shaking speed to grow and to produce antibacterial substance of the B. subtilis HS25 was 160${\sim}$200 rpm. The optimal culture time for antibacterial activities of the bacterium were shown to be in the range of 12-36 hr.

• Journal of Mushroom
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• v.6 no.3_4
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• pp.138-145
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• 2008

A Gram-positive, endospore-forming, rod-shaped bacterial strain was isolated from spent mushroom (Pleurotus eryngii) substrates taken from the Hoamfarm located in Keyollgnam, Korea. The isolate, designated CS9, was facultatively anaerobic, motile rod and produced xylanase. The strain grew optimally at $40^{\circ}C$ and pH 6.0. The major cellular fatty acids were anteiso-$C_{15:0}$, anteiso-$C_{17:0}$, and iso-$C_{17:0}$. The genomic DNA G+C content was 45 mol%. Comparative 16S-rDNA sequence analysis showed that the isolate CS9 formed a distinct phyletic line within the genus Bacillus and was most closely related to Bacillus subtilis YB1, with 16S DNA sequence similarity of 96.8%. Sequence similarities to other type strains were 92-94%. On the based of physiological and molecular properties, the isolate CS9 was classified within the genus Bacillus as Bacillus subtilis CS9.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1554-1560
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• 2006

A Gram-positive, aerobic or facultative anaerobic, non motile, endospore-forming bacterial strain, designated Gsoil $114^T$, was isolated from a soil sample of a ginseng field in Pocheon Province (South Korea), and was characterized taxonomically by using a polyphasic approach. It grew well on nutrient agar medium and utilized a limited number of organic substrates as sole carbon sources, including D-xylose and some other carbohydrates, but did not utilize L-amino acids and organic acids. The isolate was positive for oxidase test but negative for catalase, and negative for degradation of macromolecules such as starch, cellulose, xylan, casein, chitin, and DNA. The G+C content of the genomic DNA was 41.8 mol%. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major fatty acids were $anteiso-C_{15:0}$ (32.1%), $iso-C_{15:0}$ (30.5%), and $anteiso-C_{17:0}$ (30.2%). Comparative 16S rRNA gene sequence analysis showed that strain Gsoil $114^T$ fell within the radiation of the cluster comprising Bacillus species and joined Bacillus shackletonii LMG $18435^T$ with a bootstrap value of 95%. The highest 16S rRNA gene sequence similarities were found with Bacillus shackletonii LMG $18435^T$ (97.6%), Bacillus acidicola DSM $14745^T$ (96.9%), Bacillus sporothermodurans DSM $10599^T$ (96.5%), and Bacillus oleronius DSM $9356^T$ (96.5%). The phylogenetic distance from any other validly described species within the genus Bacillus was less than 96%. DNA-DNA hybridization experiments showed that the DNA-similarities between strain Gsoil $114^T$ and closest phylogenetic neighbors were less than 39%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil $114^T$ (=KCTC $13944^T$=DSMZ $18134^T$) was classified in the genus Bacillus as the type strain of a novel species, for which the name Bacillus ginsengihumi sp. nov. is proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.138-143
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• 2023

In this study, the crack healing performance of each crack healing agent manufacturing method was analyzed by adding crack healing agents in the form of alginate gel and spore suspension inoculated with endospores of calcium carbonate-forming bacteria to mortar. In addition, by applying it to an full-scale structure in the form of a box-type culvert, we attempted to create an environment in which the developed crack healing agent can be applied not only to a laboratory environment but also to an actual field. The crack healing agent using the dry heat drying method showed crack healing performance, but in the case of the freeze drying method, many spores were killed by freeze hardening and therefore the crack healing performance was lost. As a result of SEM and XRD pattern analysis of the presumed crack healing material extracted from the crack of a full-scale structure, it was found to be calcite, one of the calcium carbonate crystals produced by microorganisms applied to the crack healing agent. In conclusion, it was found that the crack healing by microorganisms can be implemented in a real structure.

• Korean Journal of Microbiology
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• v.48 no.2
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• pp.134-140
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• 2012

Asian dust storms originating in the arid desert of China and Mongolia usually occur from late winter through spring, and more than one million tons of dust per year is transported to the Korean Peninsula by the prevalent westerly winds. We supposed that these dust particles could include bioaerosols and act as carriers of microorganisms. In order to clarify the dynamics of microorganisms moving with these particles, the concentration and composition of microorganisms associated with settled particles were compared between samples collected during Asian dust events and those under non-dust periods. From February to April 2008, settled dust particles were collected at one location in Ulsan using rainfall meter of 200 mm diameter. During this period, there was one Asian dust event in Ulsan. The bacterial concentrations were higher in samples collected during Asian dust event than those under non-dust period, whereas fungal concentrations were rather similar regardless of the Asian dust event. We analyzed 16S rRNA gene sequences of 45 bacterial isolates obtained from the settled particle samples. These isolates belonged to either genus Bacillus or genus Streptococcus and were tentatively identified as B. amyloliquefaciens, B. aryabhattai, B. atrophaeus, B. licheniformis, B. megaterium, B. methylotrophicus, B. pumilus, B. sonorensis, B. subtlis, B. vallismortis, S. epidermidis, and S. succinus. In cases of fungal isolates, genera such as Mucor, Alternaria, Cladosporium, and Aspergillus were tentatively identified from samples collected at both Asian dust and non-Asian dust periods. It appears that endospore-forming bacteria such as Bacillus sp. rather than fungal spores are more likely to be associated with Asian dust particles.