• Title/Summary/Keyword: killed bacteria

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Effect of Biocide (NaOCl) in Industrial Cooling Water on Biofilm Formation and Metal Corrosion. (공장냉각수에서 Biocide (NaOCl)가 생물막 형성 및 금속 부식에 미치는 영향)

  • 강용호;박대규
    • Microbiology and Biotechnology Letters
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    • v.30 no.1
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    • pp.86-90
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    • 2002
  • Cooling water sampled at Pohang Steel Company, Korea, was used to study the effect of biocide (NaOCl) on biofilm formation and metal corrosion. Planktonic microorganisms were killed in the presence of biocide (0.2% NaOCl) within 1.5 h, but not sessile microorganisms in biofilms even after one week. Black color of biofilms, possibly due to the activity of sulfate reducing bacteria, were made with the natural cooling waters, while orange color of biofilms were formed when cooling waters were autoclaved or when 0.2% NaOCl was added to the natural cooling waters. Microbially influenced corrosion rate in black color of biofilms was 2.3 fold higher than that in orange color of biofilms.

A Bacteriocin of 5-kDa in Size Secreted by Bacillus subtilis 168 (Bacillus subtilis 168 균주가 분비하는 5 kDa 크기의 Bacteriocin)

  • Kwon, Gun-Hee;Lee, Hwang-A;Kim, Jeong-Hwan
    • Microbiology and Biotechnology Letters
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    • v.38 no.2
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    • pp.163-167
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    • 2010
  • Bacillus subtilis 168 secreted antimicrobial substance(s) into culture medium and culture supernatant inhibited growth of some Gram positive bacteria. B. cereus and Listeria monocytogenes were the most sensitive organisms. The antimicrobial activity was destroyed when culture supernatant was treated by protease and proteinase K, indicating the proteinous nature of the substance (bacteriocin). The molecular weight of the bacteriocin was estimated to be 5 kDa by Tricine SDS-PAGE. B. cereus ATCC 14579 cells were killed when exposed to the bacteriocin, indicating that the mode of inhibition was bacteriocidal. These results show that B. subtilis 168 could be useful as a starter for fermented foods such as cheonggukjang where B. cereus contamination is a major concern.

Effect of Hydroxyl Radicals on Photosynthesis Pigments of Phytoplankton in Ship's Ballast Water of 20t/h

  • Bai, Xiyao;Bai, Mindong;Zhang, Zhitao;Bai, Mindi;Yang, Bo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2004.05a
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    • pp.43-48
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    • 2004
  • A pilot-scale system of 20t/h for the treatment of ship's ballast water and the setup of dissolved hydroxyl radical was introduced in this paper. With this experimental system, the kill efficiencies of bacteria, mono-algae, protozoan reach 100% within 2.67s when dissolved OHㆍconcentration is 0.6mg/L. At the same time, the effect of hydroxyl radicals on the photosynthesis pigments of phytoplankton was done. The results indicate that the contents of chi-a, chl-b, chl-c and carotenoid are decreased to 35~64% within 8.0s further to the lowest limit of test after 5 minutes. When dissolved OHㆍratio concentration is 0.68mg/L, the attenuation efficiencies of photosynthesis pigment are 100%. Therefore the invasive marine species can be killed in the process of the inputting and discharge ship's ballast water.

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Effects of Intraperitoneal Administration of Lactococcus lactis ssp. lactis Cellular Fraction on Immune Response

  • Kim, Ji-Yeon;Lee, Seong-Kyu;Jeong, Do-Won;Hachimura, Satoshi;Kaminogawa, Shuichi;Lee, Hyong-Joo
    • Food Science and Biotechnology
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    • v.14 no.3
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    • pp.405-409
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    • 2005
  • Cellular components of Lactococcus lactis ssp. lactis (heat-killed whole cells, cytoplasm, and cell walls) were tested for their in vivo immunopotentiating activities. Peritoneal macrophages from mice injected intraperitoneally with cell-wall fractions exhibited significantly greater phagocytic activity than groups injected with whole cells or cytoplasm fraction. Cytotoxicity of natural-killer cells was highest in cytoplasm fractions. Production of cytokines (IFN-${\gamma}$, IL-2, IL-6, and IL-12) in spleen cells was significantly higher when cellular components were injected intraperitoneally, and tended to be higher in whole-cell and cytoplasm groups than in cell-wall group. These results demonstrate lactic acid bacteria whole cells and their cytoplasm and cell-wall tractions have immunopotentiating activities.

Physicochemical Analysis of Yogurt Produced by Leuconostoc mesenteroides H40 and Its Effects on Oxidative Stress in Neuronal Cells

  • Lee, Na-Kyoung;Lim, Sung-Min;Cheon, Min-Jeong;Paik, Hyun-Dong
    • Food Science of Animal Resources
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    • v.41 no.2
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    • pp.261-273
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    • 2021
  • Leuconostoc mesenteroides H40 (H40) was isolated from kimchi, and its probiotic properties and neuroprotective effect was evaluated in oxidatively stressed SH-SY5Y cells. H40 was stable in artificial gastric conditions and can be attached in HT-29 cells. In addition, H40 did not produce β-glucuronidase and showed resistant to several antibiotics. The conditioned medium (CM) was made using HT-29 cells refined with heat-killed probiotics (Probiotics-CM) and heated yogurts (Y-CM) to investigate the neuroprotective effect. Treatment with H40-CM not only increased cell viability but also significantly improved brain derived neurotropic factor (BDNF) expression and reduced the Bax/Bcl-2 ratio in oxidatively stress-induced SH-SY5Y cells. Besides, probiotic Y-CM significantly increased BDNF mRNA expression and decreased Bax/Bcl-2 ratio. The physicochemical properties of probiotic yogurt with H40 was not significantly different from the control yogurt. The viable cell counts of lactic acid bacteria in control and probiotic yogurt with H40 was 8.66 Log CFU/mL and 8.96 Log CFU/mL, respectively. Therefore, these results indicate that H40 can be used as prophylactic functional dairy food having neuroprotective effects.

Immunological characteristics of Edwardsiella tarda grown under iron-restricted condition (철 결핍 조건에서 배양된 Edwardsiella tarda의 면역학적 특성)

  • Choi, Hyun-Suk;Park, Su-Il;Lee, Deok-Chan
    • Journal of fish pathology
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    • v.19 no.1
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    • pp.45-54
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    • 2006
  • The immunogenicity of Edwardsiella tarda was surveyed under two different culture conditions. In SDS-PAGE patterns of the outer membrane proteins (OMPs) extracts of E. tarda, grown under Trypic soy broth (TSB) and TSB supplemented iron chelate 2,2‘-dipyridyl iron-restricted condition, were examined. The results showed that the iron-regulated outer membrane protein (IROMPs) with molecular masses of 68 and 73 kDa were expressed by bacteria grown in iron-chelate TSB.The pathogenicity was examined by intraperitoneal injection with live E. tarda grown under TSB, iron-chelate TSB and iron-supplemented TSB. The result of pathogenicity test showed significantly high mortality in the group of live E. tarda grown under iron-chelate TSB.The effect of formalin killed cell (FKC) of TSB cultured bacteria and 2,2'-dipyridyl FKC (DP-FKC) of cultured bacteria on the iron-chelate TSB on the development of protective immunity in olive flounder was studied. The level of immune response was evaluated with immunized fish at 1, 2, 3 and 4 weeks after immunization. The numbers of specific antibody secreting cells (SASCs) showed significantly increased level at 2 week after immunization in each group. The agglutination titre of immunized fish was significantly high level at 3 weeks after immunization.The level of protection in olive flounder at 1, 2, 3 and 4 weeks after vaccination was examined by intraperitoneal challenge test with live E. tarda.

Effects of Natural Compounds from Various Plant Eradicate the Persister Cell of Edwardsiella tarda Treated with Antibiotics of Florfenicol and Amoxicillin (천연 식물 추출물 첨가에 의한 어류 에드워드증(Edwardsiellosis) 발생균인 Edwardsiella tarda에 항생제 투여로 생성되는 persister cell 저감 효과)

  • Kim, Na-Kyoung;Kweon, Dae-Hyuk;Kim, Sung-Koo
    • Journal of Life Science
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    • v.22 no.6
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    • pp.788-793
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    • 2012
  • High concentration of antibiotics has been used to treat the outbreak of edwardsiellosis caused by Edwardsiella tarda in aquaculture. However, not all of the bacteria have been killed with high concentrations of antibiotics treatment by the formation of persister cells with a dormant state. The main objective of this study was to kill persister cell using antibiotics with the addition of natural plant compounds. Antibiotics used in this study consist of 100 mg/ml florfenicol and 100 mg/ml amoxicillin. Ten natural plant compounds with persister cell inhibitor activity to E. coli were obtained from Protein Engineering and Systems Biology Lab. of Sungkyunkwan University. The persister cell inhibition activities of those natural plant compounds were evaluated in test tube. Concentrations of the antibiotics were in the ranges of 25~200 ${\mu}g/ml$. The persister cell formation was observed after 16 hours of culture. Persister cells were killed by antibiotics with natural plant compounds. Among ten natural plant compounds, Gynostemma pentaphyllum, Mallotus japonicus, and Orixa japonica showed persister cell formation inhibition activities. The optimal concentrations of G. pentaphyllum, M. japonicus, and O. japonica for the inhibitor of persister cell formation were 100 ${\mu}g/ml$, 100 ${\mu}g/ml$, and 200 ${\mu}g/ml$, respectively. In vivo study was carried out to evaluate the effect of the antibiotics with natural plant compounds using aquacultural fish, olive flounder, as test animals. G. pentaphyllum, M. japonicus, and O. japonica of 30 ${\mu}g/ml$, 10 ${\mu}g/ml$, and 10 ${\mu}g/ml$ with antibiotics reduced cumulative mortalities, showing the effectiveness of persister cell inhibition.

The Cytotoxic Effect of Vibrio vulnificus Hemolysin on the Mouse Peritoneal Macrophages (마우스 복강내 대식세포에 대한 Vibrio vulnificus Hemolysin의 세포독성)

  • Im, Ihn-Soo;Lee, Shee-Eun;Kim, Seol;Bae, Mi-Ok;Rhee, Joon-Haeng;Shin, Boo-Ahn;Cung, Sun-Sik;Ryu, Phil-Youl
    • The Journal of the Korean Society for Microbiology
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    • v.35 no.3
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    • pp.251-261
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    • 2000
  • V. vulnificus is an estuarine bacterium which causes septicemia and shock in susceptible patients. The organism produces a hemolytic cytolysin (VvH), which has a membrane damaging effect on erythrocytes. To clarify the mechanisms by which VvH might contribute to virulence, we examined its effect on macrophages. When mouse peritoneal macrophages were harvested and co-cultured with hemolysin-positive V. vulnificus strains (100 bacteria/cell), about 60% of the macrophages were killed; macrophages were not killed when co-cultured V. vulnificus strain CVD 707, a VvH-negative deletion mutant. Exposure of macrophages to filtered culture supernatants (2.5 HU/ml) and purified VvH (3 HU/ml) resulted in an increase in dead cells (80 and 90%, respectively), as determined by the trypan blue dye exclusion method and LDH release from macrophages was also increased (70 and 65.5%, respectively). The cytotoxic effect of VvH on macrophages was both the dose- and time-dependent. The VvH caused damage to the macrophage membrane and was blocked significantly by preincubation with cholesterol (p<0.01). Fetal bovine serum showed remarkable inhibition of VvH synthesis by V. vulnificus and inhibited VvH activity in culture supernatant. Cell viability was increased by 35% (p<0.01) and LDH release decreased by 28% (p<0.01) when macrophages were incubated with V. vulnificus (100 bacterial cell) in DMEM-10% FBS for 2 hr. Bacterial clearance activity of mice against V. vulnificus CVD 707 was decreased by pretreatment with 10 HU of VvH. This result suggests that the VvH can impair the membrane of macrophages and may playa role in the pathogenesis of V. vulnificus septicemia.

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Isolation of Marine Bacteria Killing Red Tide Microalgae II. Isolation and Algicidal Properties of Pseudomonas sp. LG-2 Possessing Killing Activity for Dinoflagellate, Prorocentrum micans (적조생물 살조세균 탐색 II. 적조생물 Prorocentrum micans 살조세균 Pseudomonas sp. LG-2의 분리와 살조특성)

  • LEE Won-Jae;PARK Young-Tae
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.6
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    • pp.852-858
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    • 1998
  • We have isolated a bacterial strain that tends to kill P. micans from the mixed culture of p. minns plus seawater filtrate (poresize, 0.8 $\mu$m) collected at Masan bay in July 1996, in which the mixed culture grown in the f/2 medium. According to the experimental results of the isolated bacterium such as fatty acids analysis, morphological and biochemical characteristic tests, the strain was supposed to be a Pseudomonas and then it was named as Pseudomonas sp. LG-2. The killing effect of Pseudomonas sp. LG-2 against P. micans was proportionally increased with the concentrations of culture filtrate (pore size, 0.8 $\mu$m) is well as with the number of bacterium inoculated. In the mixed culture inoculated with $1.3\times10^6$ cells/ml of Pseudomonas sp. LG-2, the number of P. micans (2,000 cells/ml) was gradually decreased and then killed below 100 cells/ml within 7 days. In addition, the culture filtrate with $30\%$ of final concentration revealed a significant killing effect against P. micans around 3 days after culture. In the relationship between killing effects and growth stage of Pseudomonas sp. LG-2, the culture filtrate at lag phase has little effects on P. micans. In constant, the culture filtrate at mid-log phase showed the killing effect by decreasing P. micans to 112 in number within 5 days. In particular, the culture filtrate at stationary phase showed a significant killing effect against P. micans in which the majority of it was killed after 3 day culture. The species specificity of killing effects of Pseudomonas sp. LG-2 against 5 species of dinoflagellate was only found in P. micans and Scrippsiella trochoidea.

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Bacterins to Prevent the Contamination of Vbrio vulnificus in the Flounder, Paralichthys olivaceus (넙치에서의 Vbrio vulnificus 오염 방지를 위한 백신 연구)

  • Son Sang Gyu;Kim Myoung Sug;Park Jun Hyo;Yoo Min Ho;Jeong Hyun Do
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.35 no.1
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    • pp.1-7
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    • 2002
  • To study the increased resistance in fish against Vibrio vulnificus known as an important agent of vibrio septicemia in human, we analyzed specific and nonspecific immune response in flounder after administration of V. vulnificus bacterins by oral route. It contained the comparison of antibody concentrations in the sera of flounder after oral administration by two different protocols with uncoated heat killed bacterin of V vulnificus (UHKB, 20 mg/kg body weight), i.e., 4 weeks continuously (group 4W) and taking 2 weeks resting period between the 1st and last week of administration (group 1-2-1W). Even though, 1-2-1W group showed significantly increased level of specific antibody in serum, it did not reach to that of 4W group. Certainly, flounder vaccinated twice a week for four weeks (20 mg/kg b.w.) showed increased concentration of specific antibody against V. vulnificus at week 2 after last administration by oral route and maintained throughout the experimental period. It also was confirmed by the increased numbers of specific antibody secreting cells (SASC) in the leukocytes isolated from the splenocytes of the flounder of 4W group at week 1 after last administration until the end of experimental period. However, enteric, acid-resistant film coated heat killed bacterin (ECHB) did not show both greater immune reaction for antibody production and faster elimination of a challenge dose of V. vulnificus compared with those of the UHKB. These results suggested that UHKB administered by oral route was very effective method to prevent the contamination of V vulnificus in flounder, and did not show the increased antigenicity by coating the surface with acid-resistant film.