• Natural Product Sciences
• /
• 제19권4호
• /
• pp.297-302
• /
• 2013

The current study was conducted to evaluate the antibacterial and antioxidant activities of the essential oil fraction from the roots of Angelica tenuissima Nakai and its main components. We extracted the essential oil fraction from the roots of A. tenuissima using steam distillation and isolated its main components. Their antibacterial activities were determined by broth dilution test against food-borne pathogenic bacteria. Antioxidant activities were evaluated by DPPH-scavenging assay and reducing-power test. Also tested was their ability to inhibit the growth of two gastrointestinal cancer cell lines, Caco-2 and MKN-45. The A. tenuissima oil fraction and its main components, ligustilide and butylidene phthalide exhibited marked inhibitory effects against most of the tested antibiotic-susceptible and antibiotic-resistant bacterial strains with minimum inhibiting concentrations (MICs) from $0.21{\pm}0.08$ to $3.60{\pm}0.89mg/ml$. They also showed growth-inhibiting activity against Caco-2 and MKN-45 cells. The oil fraction showed significant antioxidant activities in DPPH radical scavenging assay and reducing-power test. Taken together, A. tenuissima essential oil could be used as a safe additive for preventing food contamination by pathogenic bacteria. Additionally, its antioxidative activity and the ability to inhibit gastrointestinal carcinoma cell lines could increase its value for functional foods and prevention of cancer.

• 한국미생물·생명공학회지
• /
• 제30권2호
• /
• pp.129-134
• /
• 2002

토종닭 소장으로부터 가축 소화기 병원성 유해세균의 분리를 위하여 무작위 선별법과 중층-도말법을 사용하여 총130주의 유산균을 1차 분리하였다. 1차 분리한 130주를 paper disc법을 사용하여 최종적으로 살모넬라 균, 포도상구균, 대장균에 대하여 저해능이 우수한 7주를 분리하였다. 분리 균주의 동정을 위하여 1차로 API CHL kit를 사용하였고, 동정의 정확성을 높이기 위하여 2차로 16S rRNA sequencing 방법을 사용하였다. 그 결과 BD14 균주는 Pediococcus pentosaceus로 동정되었으며 나머지 6주는 Lactobacillus sp.로 동정되어 모두 안전성 있는 유산균임을 확인하였다. 여러 병원균에 가장 항균력이 큰 유산균은 L. pentosus K34이었으며, 이 유산균은 염산과 담즙산에 대한 내성에서도 가장 우수한 균주로 나타났다. 10종의 항생제에 대한 감수성을 조사한 결과 ciprofloxacin에 대하여 모든 균주가 내성을 보였고, BL 균주를 제외하고 모든 균주가 colistin, streptomycin에 대하여 내성을 보였다. 또한 BD14, BD16, K34 균주가 gentamicin에 대한 내성을 보였다.

• Journal of Dairy Science and Biotechnology
• /
• 제39권2호
• /
• pp.51-62
• /
• 2021

Escherichia coli are the predominant facultative bacteria found in the gastrointestinal tract of animals and humans. Some strains of E. coli that acquire virulence factors and cause foodborne and waterborne diseases in humans are called pathogenic E. coli and can be divided into five pathotypes according to the virulence mechanism: EAEC, EHEC, EIEC, EPEC, and ETEC. Although selective media have been developed to detect E. coli, distinguishing pathogenic strains from non-pathogenic ones is difficult because of their similar biochemical properties. Therefore, it is very important to find a new and effective diagnostic method to identify pathogenic E. coli. With recent advances in molecular biology and whole genome sequencing, the use of polymerase chain reaction (PCR) is increasing rapidly. In this review paper, we provide an overview of pathogenic E. coli and present a review on PCR detection methods that can be used to diagnose pathogenic E. coli. In addition, the possibility of real-time PCR incorporating IAC is introduced. Consequently, this review paper will contribute to solving the current challenges related to the detection of pathogenic E. coli.

• 한국미생물·생명공학회지
• /
• 제48권3호
• /
• pp.276-286
• /
• 2020

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefits to the host. This study was conducted for the isolation of potential lactic acid bacteria (LAB) with probiotic properties from goat milk and yogurt. Several tests were conducted in vitro using the standard procedures for evaluating the inhibitory spectra of LAB against pathogenic bacteria; tolerance to NaCl, bile salt, and phenol; hemolytic, milk coagulation, and bile salt hydrolase activities; gastrointestinal transit tolerance; adhesion properties; and antibiotic susceptibility. Among 40 LAB strains screened according to culture characteristics, five isolates exhibited antagonistic properties. Three were identified as Pediococcus acidilactici, and two were identified as Enterococcus faecium, exploiting 16S rRNA gene sequencing. All the isolates succeeded in the gastrointestinal transit tolerance assay and successively colonized mucosal epithelial cells. Based on the results of these in vitro assays, both P. acidilactici and E. faecium can be considered as potential probiotic candidates.

• Journal of Animal Science and Technology
• /
• 제58권7호
• /
• pp.26.1-26.11
• /
• 2016

The use of probiotics for human and animal health is continuously increasing. The probiotics used in humans commonly come from dairy foods, whereas the sources of probiotics used in animals are often the animals' own digestive tracts. Increasingly, probiotics from sources other than milk products are being selected for use in people who are lactose intolerant. These sources are non-dairy fermented foods and beverages, non-dairy and non-fermented foods such as fresh fruits and vegetables, feces of breast-fed infants and human breast milk. The probiotics that are used in both humans and animals are selected in stages; after the initial isolation of the appropriate culture medium, the probiotics must meet important qualifications, including being non-pathogenic acid and bile-tolerant strains that possess the ability to act against pathogens in the gastrointestinal tract and the safety-enhancing property of not being able to transfer any antibiotic resistance genes to other bacteria. The final stages of selection involve the accurate identification of the probiotic species.

• Journal of Microbiology and Biotechnology
• /
• 제33권7호
• /
• pp.857-863
• /
• 2023

Pathogenic bacteria that colonize the human intestinal tract have evolved strategies to overcome acidic conditions when they pass through the gastrointestinal tract. Amino acid-mediated acid resistance systems are effective survival strategies in a stomach that is full of amino acid substrate. The amino acid antiporter, amino acid decarboxylase, and ClC chloride antiporter are all engaged in these systems, and each one plays a role in protecting against or adapting to the acidic environment. The ClC chloride antiporter, a member of the ClC channel family, eliminates negatively charged intracellular chloride ions to avoid inner membrane hyperpolarization as an electrical shunt of the acid resistance system. In this review, we will discuss the structure and function of the prokaryotic ClC chloride antiporter of amino acid-mediated acid resistance system.

• Fisheries and Aquatic Sciences
• /
• 제6권1호
• /
• pp.27-33
• /
• 2003

A lactic acid bacterium showing antimicrobial activity against fish pathogen was isolated from gastrointestinal tract of flounder for the purpose of use as an aquaculture probiotics. From the analysis of morphological and physiological characteristics, the isolated strain was named as Lactococcus sp. HM58. Antimicrobial substance (AMS) from Lactococcus sp. HM58 showed strong growth inhibitory activity against Streptococcus sp., which is a fish pathogenic bacterium. AMS was presumed a proteinaceous compound with stability in heat and wide pH range from 2 to 10. It was started to produce in exponential growth phase and was not produced any more in stationary phase. It showed comparatively broad antimicrobial spectrum against most of gram positive bacteria used for this study. About $84\%$ of Lactococcus sp. HM58 was able to survive in the artificial gastric juice though it was low to the extent in the artificial bile juice. In the sensitivity test for various antibiotics, this strain was highly sensitive for doxycycline, erythromycin, amoxicillin clavu1anic acid and ampicillin.

• 생명과학회지
• /
• 제32권5호
• /
• pp.391-410
• /
• 2022

인간 미생물 균총은 장, 구강, 피부와 같이 체내외 다양한 부위에 존재하는 박테리아, 균류, 바이러스 등을 포함하는 미생물 집단이다. 16s ribosomal RNA에 대한 대사체 분석 및 차세대 염기서열 분석기술의 개발과 함께, 살아있는 유기체 내에 존재하는 미생물 균총에 대한 많은 연구가 진행되었다. 이에 따라, 미생물 균총이 숙주의 대사 및 면역과정과 복잡하게 연관되어 있음이 확인되었다. 공생균(commensal microbiota)이라 불리는 미생물 균총의 특정 박테리아가 필수 영양소를 생성하거나 다른 병원성 미생물로부터 숙주를 보호하여 긍정적으로 영향을 미치고 있는 반면, 비정상적인 미생물 균총의 조성을 의미하는 미생물 균총의 불균형(dysbiosis)에 의해 체내 항상성 유지를 방해하여 다양한 종류의 질병을 발생시키기도 한다. 최근, 미생물 균총 중에서도 구강과 장내 존재하는 박테리아가 위장관암의 발암과정과 항암제의 치료효과에 상당한 영향을 미치고 있음이 여러 논문을 통해 보고되고 있다. 미생물 균총-암-면역계 사이의 복잡한 연관성과 미생물 균총 기반 발암 메커니즘에 대한 규명은 암에 대한 이해와 새로운 항암제 개발에 중요한 단서를 제공할 것으로 기대된다. 본 리뷰는 미생물 균총의 박테리아가 위장관암과 항암제에 어떤 영향을 미치고 있는지에 대해 초점을 맞추고 있는 논문들을 요약하고 있으며, 나아가 기존 항암제의 치료효과를 개선하기 위해 복합제로써 미생물 균총의 잠재력과 도전과제에 대해 논의한다.

• Journal of Dairy Science and Biotechnology
• /
• 제32권1호
• /
• pp.1-6
• /
• 2014

Probiotics have been extensively studied for their beneficial effects on human health. In particular, Lactobacillus and Bifidobacterium strains have gained considerable attention as major groups of probiotic bacteria that improve gastrointestinal health. However, emerging evidence suggests that probiotics offer benefits beyond those observed in the gut recent studies suggest that probiotics and/or their components exert favorable effects on alcoholic liver disease (ALD) pathogenesis such as decreasing intestinal permeability, inhibiting pathogenic bacteria growth, increasing the activity of alcohol metabolism enzymes, modulating the adaptive immune system, and suppressing fatty acid synthesis genes. In this review, we discuss the results of in vivo and in vitro studies that have examined the use of probiotics to prevent ALD, primarily focusing on those that explore the cellular and molecular mechanisms underlying the activities of promising probiotic strains. The evidence presented in this review could help in screening for probiotic strains that have protective effects in ALD patients and in further elucidating the mechanisms of their actions.

• KSBB Journal
• /
• 제23권1호
• /
• pp.65-69
• /
• 2008

가축 질병의 제어를 위해 면역증강제인 베타글루칸 생성균으로 분리한 Paenibacillus polymyxa JB115의 배양액이 가축병원성 세균에 대한 항균성을 보임에 따라, 배양액의 동결건조 분말을 대상으로 항균물질의 특성을 조사하여 다기능 가축 사료첨가제로의 개발 가능성을 타진하였다. 그 결과, P. polymyxa JB115에서 생산된 항균물질은 E. coli, S. aureus, S. choleraesuis 및 P. aeruginosa 등 가축 병원성 세균들에 대해 살균 또는 정균 활성을 보였으며, 항균범위도 광범위하게 나타났다. 또한 이 물질은 높은 내열성과 pH 안정성을 지녀 배양액의 제형화에도 적합하였으며, 인공 담즙산 및 인공 위액에서도 안정하여 사료첨가제로 투여시 가축의 장내 병원세균에 대해서 항균 활성을 충분히 나타낼 수 있을 것으로 판단되었다. 상기의 결과로부터 P. polymyxa JB115의 배양액은 베타글루칸 이외에도 가축 병원성 세균에 대한 항균물질을 지니고 있어서, 다기능 사료첨가제로 개발 가능함을 확인하였다.