• Journal of Microbiology and Biotechnology
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• 제19권11호
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• pp.1393-1400
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• 2009

A bacteriocin-producing strain PI80 was isolated from the gut of Penaeus indicus (Indian white shrimp) and identified as Streptococcus phocae PI80. The bacteriocin was purified from a culture supernatant to homogeneity as confirmed by Tricine SDS-PAGE. Reverse-phase HPLC analysis revealed a single active fraction eluted at 12.94 min, and MALDI-TOF mass spectrometry analysis showed the molecular mass to be 9.244 kDa. This molecular mass does not correspond to previously described streptococcal bacteriocins. The purified bacteriocin was named phocaecin PI80 from its producer strain, as this is the first report of bacteriocin production by Streptococcus phocae. The bacteriocin exhibited a broad spectrum of activity and inhibited important pathogens: Listeria monocytogenes, Vibrio parahaemolyticus, and V. fischeri. The antibacterial substance was also sensitive to proteolytic enzymes: trypsin, protease, pepsin, and chymotrypsin, yet insensitive to catalase, peroxidase, and diastase, confirming that the inhibition was due to a proteinaceous molecule (i.e., the bacteriocin), and not due to hydrogen peroxide or diacetyl. Phocaecin PI80 moderately tolerated heat treatment (up to $70^{\circ}C$ for 10 min) and resisted certain solvents (acetone, ethanol, and butanol). A massive leakage of $K^+$ ions from E. coli $DH5\alpha$, L. monocytogenes, and V. parahaemolyticus was induced by phocaecin PI80, as measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES). Therefore, the results of this study show that phocaecin PI80 may be a useful tool for inhibiting L. monocytogenes in seafood products that do not usually undergo adequate heat treatment, whereas the cells of Streptococcus phocae PI80 could be used to control vibriosis in shrimp farming.

• 한국가금학회지
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• 제34권3호
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• pp.187-196
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• 2007

본 연구는 식물 추출물, 한방 발효물 및 유산균을 육계에 단독 또는 혼합 급여하였을 때 생산성, 혈액 특성, 맹장 미생물 균총 및 소장 내 소화 효소 활성에 미치는 영향을 조사하고 이를 통해 이들의 성장 촉진용 항생제(AGP) 대체 가능성 및 효과적인 이용 방법을 구명하고자 실시하였다. 1일령 육계 수평아리(Ross strain) 840수를 공시하여 7처리 4반복 반복당 30수씩 완전 임의 배치하였다. 시험구는 항생제 무첨가구(NC)와 항생제 첨가구(PC)를 대조구로 하였으며, 시험 사료에 식물 추출물, 한방 발효물 및 유산균을 0.1% 수준으로 첨가한 처리구(PE, FMP 및 LB)와 유산균 0.1%를 혼합한 시험사료에 식물 추출물 및 한방 발효물을 0.1%씩 첨가한 처리구(PE+LB 및 FMP+LB)를 두었다. 5주 종료 체중 및 증체량은 무항생제 대조구에 비해 모든 처리구에서 유의하게 증가하거나(P<0.05) 증가하는 경향을 보였다. 사료 요구율에 있어서도 무항생제 대조구(NC)에 비해 모든 처리구에서 개선되었다(P<0.05). 그러나 식물 추출물 0.1% 첨가구(PE)을 제외한 다른 처리구에서는 항생제 대조구(PC)와 비교해서 생산성이 감소하는 경향을 보였으며, 식물 추출물 및 한방 발효물과 유산균 혼합에 따른 상승 효과는 관찰되지 않았다. Albumin : globulin 비율은 대조구에서 유의하게 감소하였으며(P<0.05), 백혈구 조성에 있어서 스트레스 지표인 림프구/호중구 비율이 역시 무항생제 대조구에 비해 모든 처리구에서 유의하게 낮아졌다(P<0.05). 맹장 내 총 균수 및 Lactobacillus 수에 있어서 처리구 간 차이가 관찰되지 않았다. E. coli 및 Salmonella의 수는 한방 발효물 0.1% 및 유산균 0.1% 단독 첨가구에서 유의하게 감소하였다(P<0.05). 소장 내 소화 효소 활성은 sucrase를 제외한 다른 소화 효소의 활성이 대조구에 비해 유의하게 감소하였다(P<0.05). 본 연구 결과 식물 추출물 및 유산균 급여는 육계 생산성을 향상시키고, 혈액 특성에 긍정적인 영향을 미쳐 항생제 대체제로서의 이용 가능성이 있을 것으로 생각된다.

• 한국축산식품학회지
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• 제33권1호
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• pp.75-82
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• 2013

This study aimed to isolate lactic acid bacteria (LAB) from Kimchi and to identify suitable probiotic strain for application in fermented dairy product as a commercial starter culture. A total of 106 (LAB) strains were isolated from Kimchi collected from different regions in Korea and their phenotypic characteristics were assayed. Four isolates from MRS agar plates were selected and designated as DKL109, DKL119, DKL121 and DKL128. They were identified first by API 50 CHL kit and then 16S rRNA gene sequencing. DKL121 and DKL128 were identified as Lactobacillus paracasei and Lactobacillus casei, respectively. Other two isolates (DKL109 and DKL119) were identified as Lactobacillus plantarum. To estimate their applicability in dairy products, the characteristics including acid and bile tolerance, cold shock induced cryotolerance and enzymatic activities were determined. There was wide variation in ability of strains to acid tolerance, but no significant differences in bile tolerance, cold shock induced cryotolerance within selected strains. DKL119 and DKL121 showed the highest resistance to acid and bile and the highest ${\beta}$-galactosidase activity, respectively. When these two strains were used for yogurt preparation as a single starter culture, their viable cell counts reached to $1.0{\times}10^9CFU/mL$. Lactobacillus plantarum DKL119 showed faster acid development than commercial starter culture. Also storage trials at $10^{\circ}C$ showed that the viability of these strains was retained over 15 d. With these results, it was indicated that probiotics isolated from Kimchi can be used in yogurt manufacturing as a starter culture.