• Journal of Microbiology and Biotechnology
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• v.27 no.8
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• pp.1441-1448
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• 2017

Antibacterial compounds are widely used in the treatment of human and animal diseases. The overuse of antibiotics has led to a rapid rise in the prevalence of drug-resistant bacteria, making the development of new antibacterial compounds essential. This study focused on developing a fast and easy method for identifying marine bacteria that produce antibiotic compounds. Eight randomly selected marine target bacterial species (Agrococcus terreus, Bacillus algicola, Mesoflavibacter zeaxanthinifaciens, Pseudoalteromonas flavipulchra, P. peptidolytica, P. piscicida, P. rubra, and Zunongwangia atlantica) were tested for production of antibacterial compounds against four strains of test bacteria (B. cereus, B. subtilis, Halomonas smyrnensis, and Vibrio alginolyticus). Colony picking was used as the primary screening method. Clear zones were observed around colonies of P. flavipulchra, P. peptidolytica, P. piscicida, and P. rubra tested against B. cereus, B. subtilis, and H. smyrnensis. The efficiency of colony scraping and broth culture methods for antimicrobial compound extraction was also compared using a disk diffusion assay. P. peptidolytica, P. piscicida, and P. rubra showed antagonistic activity against H. smyrnensis, B. cereus, and B. subtilis, respectively, only in the colony scraping method. Our results show that colony picking and colony scraping are effective, quick, and easy methods of screening for antibacterial compound-producing bacteria.

• Korean Journal of Veterinary Service
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• v.40 no.4
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• pp.265-275
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• 2017

The production of enzymes that help digestion, assimilation of essential nutrients, and prevent pathogenic bacteria are important for probiotics used in aquaculture. The objective of this study was to investigate enzyme activities for macromolecular organic matters and antimicrobial properties of the selected potential probiotics isolated from gut of surf clam (Tresus keenae) against well-known shellfish-pathogenic bacteria. Among 65 isolates from guts of 60 surf clams, seven Bacillus strains with outstanding degradation capability of macromolecule organic matter were selected as potential probiotics as follows: TKI01 (B. vietnamensis), TKI02, TKI26 (B. thuringiensis), TKI14, TKI32, TKI42 (B. amyloliquefaciens), and TKI18 (B. stratosphericus). After in vitro antimicrobial activity test was performed against five shellfish-pathogenic bacteria including Listonella anguillarum, Vibrio parahaemolyticus, V. splendidus, V. harveyi, V. tubiashii, PCR assay was performed to detect bacteriocin-producing strain. PCR results revealed that the five Bacillus strains possessed diverse bacteriocin genes including ericinA, coagulin, surfactin, iturin, bacyllomicin, fengycin, bacylisin, subtilin, and lantibiotics. In the present study, the selected seven Bacillus strains showed different enzyme activities according to types of macromolecule organic matters. And their antimicrobial activities varied based on the species of pathogenic bacteria. In addition, at least five Bacillus strains had genetic potential to produce several natural lipopeptide antibiotics that may help biological control of surf clam aquaculture. Therefore, mixed use of probiotics might show co-operative effect and increase the efficiency of probiotics rather than separate use. To the best of our knowledge, it is the first report on antimicrobial properties of Bacillus species isolated from surf clam.

• Korean Journal of Veterinary Research
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• v.16 no.1
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• pp.27-34
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• 1976

악상남도(惡尙南道) 김해군(金海郡) S 양돈장(養豚場)에서 1975년 4월 하순부터 5월 하순 사이에 사육돈(飼育豚) 1,200두중 약 350두에서 출혈성하리(出血性下痢)를 주증(主症)으로 하는 전염성(傳染性)이 강한 소화기질환(消化器疾患)이 발생하였다. 환돈(患豚)은 7주령(週齡)에서부터 14주령(週齡)까지에서 가장 많이 발생하고 급성(急性) 또는 아급성(亞急性)으로 경과하였으며 다량의 황백색(黃白色), 수양하리(水樣下痢)를 발하다가 황갈색(黃褐色), 포말성하리(泡沫性下痢) 또는 암적갈색(暗赤褐色) 점액성하리(粘液性下痢)를 나타내었다. 육안적(肉眼的) 병변(病變)은 대장(大腸)에 한하였으며 카타아르성(性), 출혈성(出血性) 내지 괴사성장염(壞死性腸炎)을 시현(示顯)하였으며 괴사(壞死)는 광범(廣凡)하나 표재성(表在性)이고 어떤 예에서는 결장점막(結腸粘膜) 속에 대소(大小)의 미세결절(微細結節)이 밀발(密發)한 것이 특징이었다. 조직학적검사(組織學的檢査)에서는 대장점막(大腸粘膜)에 현저한 배세포증식(杯細胞增殖), 울혈(鬱血) 및 원형세포침윤(圓形細胞浸潤)과 더불어 표재성괴사(表在性壞死)가 관찰되었고 상기(上記) 결절(結節)은 장선(腸腺) 속에 점액(粘液), 섬유소(纖維素) 및 붕괴세포(崩壞細胞)가 축적되어 선와(腺窩)가 확장되고 피복상피(被覆上皮)의 이형성(異形成)(dysplasia)을 일으키고 있음이 판명되었다. 병변부(病變部)의 세균염색(細菌染色)에 의하여 대형(大型) Spirocheta와 Vibrio 고균(孤菌)이 무수(無數)히 발견되었고 Spirocheta가 병변형성(病變形成)에 더 밀접하게 관련되어 있음이 밝혀졌다.

• Korean Journal of Microbiology
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• v.30 no.6
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• pp.444-449
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• 1992

A total of 858 heterotrohic bacteria were isolated and analyzed hy numerical method to investigate the heterotrophic hacterial community structure in Naktong Estuary. Although the values of H' (Shannon's diversity index). ranged between 1.54 and 3.49. were similar with those of the data hefore the construction of Naktong River barrage, however J' (evenness index. 0.31-0.80) was reduced. Physiological tolerance index for water temperature ($P_{s}$) was high at St.l and 2 whose depthes arc shallower than the other stations. and indices for pH ($P_{h}$) and salinity ($P_{s}$) were high at St. 2. 3. 4 where freshwater and seawater arc mixed. The predominant clusters were identified as Aeromonas. Vihrio. Pseudomonas. Acinelobacter-Morexella. Alcaligenes. Flavobacterium. Micrococcaccae. and Enterohacteriaceae. The kinds nf the isolates were similar with the previous result. hut the dominant genus was changed. These results suggest that the environmental changes in Naktong Estuary affect the hacterial physiological adaptation rather than the composition of heterotrophic hactcrial community.

• The Korea Journal of Herbology
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• v.30 no.4
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• pp.29-35
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• 2015

Objectives : The objective of this research was to investigate the antibacterial and antioxidant activities of bio-fermented Sanguisorbae Radix extract.Methods : The Sanguisorbae Radix extract was fermented byStreptococcus thermophilus,and their products was tested for antibacterial activity against pathogenic microorganisms namely,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,Escherichia coli,Vibrio parahaemolyticusandSalmonella typhimuriumby paper disc diffusion method and the antioxidant activities of extract was evaluated by five different assays as electron donating ability(EDA), superoxide dismutase(SOD)-like activity, polyphenol, flavonoid contents and nitrite scavenging ability.Results : The bio-fermented Sanguisorbae Radix extract was safe from heat. Antibacterial activity of fermented Sanguisorbae Radix extract appeared relatively highly againstBacillus cereusandStaphylococcus aureusand didn't show any difference. EDA in comparison to Vitamin C showed over 90% activity at about the same time of Sanguisorbae Radix extract expressed highly. SOD activity showed 15% in fermentation before and after. The nitrite scavenging ability of Sanguisorbae Radix extract before and after fermentation showed higher numerical value over 70% in pH 2.5 than that of butylated hydroxytoluene(BHT). But SOD activity, EDA and nitrite scavenging ability were not different between the Sanguisorbae Radix extract before and after fermentation. Total polyphenol content expressed over about 20 mg/g, and that of the Sanguisorbae Radix extracts was increased than that of the fermented Sanguisorbae Radix extracts.Conclusions : The results suggest the usefulness of developing functional materials using antioxidant active Sanguisorbae Radix extract was fermented bySalmonella typhimuriumwith high polyphenol contents and nitrite scavenging ability.

• Advances in Traditional Medicine
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• v.8 no.4
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• pp.339-348
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• 2008

Butea frondosa has been used traditionally as a topical formulation in the treatment of many diseases and disorders. Two compounds [BF-1 (crystalline flavonol quercetin) and BF-2 (tannin) from ethyl acetate fraction of ethanolic extract] were isolated from the bark of Butea frondosa. The stereostructures of the compounds were determined on the basis of chemical and physicochemical evidence. BF-1 and BF-2 were screened in vitro for possible antibacterial property against 112 bacteria comprising 3 genera of Gram-positive and 12 genera of Gram-negative types. It was found that both BF-1 and BF-2 exhibited inhibitory activity against several bacteria. Most of these strains were inhibited by BF-1 at $50-200\;{\mu}g/ml$, while BF-2 ($MIC_{50}$ $400\;{\mu}g/ml$) was much less active. The bacteria could be arranged in the decreasing order of sensitivity towards BF-1 in the following manner: S. aureus, Bacillus spp., Salmonella spp., Vibrio spp., Shigella spp., E. coli and Pseudomonas spp. The $MIC_{50}$ of the compound was $50\;{\mu}g/ml$ while the $MIC_{90}$ was $100\;{\mu}g/ml$. The decreasing order of sensitivity towards BF-2 was V. cholerae, Bacillus spp., S. aureus, V. parahaemolyticus, Salmonella spp. and Proteus spp. BF-1 was bactericidal in action. In vivo studies with this extract showed that it could offer statistically significant protection (p < 0.01) to mice challenged with a virulent bacterium. The inhibitory activity of Butea frondosa against Gram-positive and Gram-negative bacteria indicates its usefulness in the treatment of common bacterial infections. The potentiality of BF-1 as an antibacterial agent may be confirmed further by pharmacological studies.

• YAKHAK HOEJI
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• v.22 no.1
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• pp.33-41
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• 1978

In order to study the growth and survival of enteric pathogens causing water-borne infections in sewage, the filter-sterilized and autoclaved sewages of Dae Gu City were inoculated with Salmonella typhimuriuim, Shigella flexneri 2a, Sh. sonnei I, Vibrio eltor and V. parahaemolyticus, as test series and Escherichia coli as control. After varying periods of incubation up to 15 days at $4^{\circ}$, $15^{\circ}$, $25^{\circ}$ and $37^{\circ}C$, viable cells in the inoculated sewages were counted by colony count technique. Distilled water and 0.9% saline were subjected to inoculation of the organisms was observed in the filter-sterilized and autoclaved sewages at $4^{\circ}$ and the sewages became sterile within a few days. At $15^{\circ}$, no growth and rapid inactivation of the organisms in the filter-sterilized sewage and slight or no growth in the autoclaved sewage was noted. Some viable cells were found in the autoclaved sewage after 15 days. A considerable growth was observed in the filter-sterilized and autoclayed sewages, at $25^{\circ}$ and $37^{\circ}$, and large numbers of viable cells were found even after 15days of incubation. In general, the autoclaved sewage supproted the growth more noticeably than the filter-sterilized, except for V.parahaemolyticus which grew well in filter-sterilized sewage. No marked difference was noted between incubations at $25^{\circ}$ and $37^{\circ}$, but V. parahaemolyticus showed a slightly more active growth at $25^{\circ}$ than at $37^{\circ}$. Distilled water inactivated the organisms within a few days, but saline supported the growth at $25^{\circ}$ and $37^{\circ}$. Marked differences were noted in the survival test of sewages pathogens of different origins.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.555-560
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• 1996

The toxic substances (endotoxins) from the bacterial cell walls were extracted by using incubator, centrifuge, UV-Vis spectrophotometer, and their fatty acid compositions were analyzed by Gas Chromatography. The lethal toxicities and pyrogenic activities of toxic substances were tested and the results were compared each other. The results of fatty acid analyses showed that the major fatty acid of the toxic substance was tetradecanoic acid for Vibrio vulnificus, dodecanoic acid for Escherichia coli, and decanoic acid for Salmonella typhimurium. These three fatty acids were the main fatty acids ofr three toxic substances (more, than 70%). The unique points in the fatty acid compositions were that tetradecanoic acid was composed as important one (37.15%) for V. vulnificus and that the amount of hexadecanoic acid was very small (below 2%) for three toxic substances. The lethal toxicity in ICR mice of toxic substance from V. vulnificus (LD50 was 52.5 mg/kg) was similar to that of E. coli (56.5mg/kg), but weaker than that of S. typhimurium (37.5mg/kg). Toxic substance from V. vulnificus was more pyrogenic in rabbit than that from E. coli, but less than that from S. typhimurium.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.187-190
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• 2000

Effects of gamma ionizing radiation on recombinant Escherichia coli cells containing stress promoters, recA, fabA, grpE, or katG, fused to luxCDABE originated from Vibrio fischeri were characterized by monitoring transcriptional responses reflected by bioluminescent output. Quantification of gamma-ray intensity may be possible using the recA and fabA promoter fusion since a linear enhancement of bioluminescence emission with increasing gamma-ray intensity was observed. Other strains sensitive to either oxidative stress (DPD2511, katG::luxCDABE) or protein-damaging stress (TV1061, grpE::luxCDABE) were also irradiated by gamma-rays, and resulted in no noticeable bioluminescent output while DPD2794 with recA promoter and DPD2540 with fabA promoter irradiated by the same intensities of gamma-rays gave a significant bioluminescent output. This indicates that the main stresses in the recombinant bacteria caused by ionizing radiation are DNA and membrane-damage, not protein- or oxidative-damage. In addition, in this study, to investigate the relationship between the radiation dose rate and bacterial responses, two recombinant Escherichia coli strains, DPD2794 and GC2, containing lac promoter fused to luxCDABE originating from Photorhapdus luminescences, were used for detecting DNA damage and cellular toxicity under various radiation dose rates. Throughout this study, it was found that these bacteria showed quantitative stress responses to DNA damage and general toxicity caused by gamma rays, depending on the radiation dose rates, indicating that the bacterial stress responses and general toxicity were seriously influenced according to radiation dose rates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.238-245
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• 2012

In this study, the molecular structures of tet(M) and tet(G) carried by tetracycline (Tc) resistant bacteria in intestinal microflora from the imported ornamental fish were characterized and compared with each other depend on the imported countries. Of the total isolates, approximately 8.9% of the Ent-lac+(lactose fermentative bacteria on coliform media) Tc resistant isolates in fish from three different countries, Singapore, Taiwan and Brazil, were appeared to contain tet(M). Three representative isolates of different countries, Aeromonas spp. JSM-1 (Singapore), JTM-1 (Taiwan) and JBM-1 (Brazil), were isolated and analyzed the molecular structures of tet(M) gene. Interestingly, partial sequence of tet(M) genes (1099 bp) in JBM-1 (Brazil) showed 99.5% homology with the tet(M) found in the Vibrio spp. RV16 isolate, obtained from marine fish in Korea and known to carry Tn1545 parent type of tet(M). In contrast, tet(M) gene in JSM-1 and JTM-1 showed mosaic structure of Tn1545 and Tn916, and 100% homology with each other. It may suggest the presence of various characteristics in terms of tet(M) gene structure. The determined sequence of the tet(G) from Aeromonas spp. JSG-1 and JBG-1 isolated from Singapore and Indonesia ornamental fish respectively showed similar nucleotide sequence homology but revealed a few nucleotide changes in comparison with the sequence of the prototype tet(G) gene (S52437 in GenBank).