• The Plant Pathology Journal
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• 제38권5호
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• pp.449-460
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• 2022

This study was performed to reveal phenotypic characters and identity of symbiont bacteria of Nasutitermes as well as investigate their potential as antagonist of plant pathogenic fungi. Isolation of the symbiont bacteria was carried out from inside the heads and the bodies of soldier and worker termite which were collected from 3 locations of nests. Identification was performed using phenotypic test and sequence of 16S ribosomal DNA (16S rDNA). Antagonistic capability was investigated in the laboratory against 3 phytopathogenic fungi i.e., Phytophthora capsici, Ganoderma boninense, and Rigidoporus microporus. Totally, 39 bacterial isolates were obtained from inside the heads and the bodies of Nasutitermes. All the isolates showed capability to inhibit growth of P. capsici, however, 34 isolates showed capability to inhibit growth of G. boninense and 32 isolates showed capability to inhibit growth of R. microporus. Two bacterial strains (IK3.1P and 1B1.2P) which showed the highest percentage of inhibition were further identified based on their sequence of 16S rDNA. The result showed that 1K3.1P strain was placed in the group of type strain and reference strains of Lysinibacillus fusiformis meanwhile 1B1.2P strain was grouped within type strain and reference strains Paenibacillus alvei. The result of this study supply valuable information on the role of symbiont bacteria of Nasutitermes, which may support the development of the control method of the three above-mentioned phytopathogenic fungi.

• KSBB Journal
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• 제14권2호
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• pp.198-204
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• 1999

Asymbiotic bacterium with highly effective toxins was isolated from entomopathogenic nematode Steinernema glaseri which has been widely used against various soil-inhabiting pests. The symbiont of S. glaseri was identified as Xenorhabdus nematophilus sp. by using several biochemical and physiological tests. When this strain was released into the hemolymph of insect larva, it produced highly toxic substances and killed the larva within 2 days. Two colony forms that differed n some biochemical characteristics were observed when cultures in vitro. Phase l colonies were mucid and difficult to be dispersed in liquid. Phase II was not mucoid and was easily dispersed in liquid. It did not adsorb neutral red or bromothymol blue. Rod-shaped cell size was highly variable between two phases, ranging 2-10 ${\mu}{\textrm}{m}$. It was also found that only infective-stage nematodes can carry only primary-phase Xenorhabdus in their intestine.

• 한국미생물·생명공학회지
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• 제20권1호
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• pp.96-101
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• 1992

폐수중의 PVA를 생물학적 처리방법에 의한 제거를 위해 자연계로부터 PVA를 분해할 수 있는 세균을 분리하였으며, 그 중 균 성장육이 높고 PVA를 강력하게 분해, 자화할 수 있는 G5Y 균주와 PW 균주를 선별하여 동정 및 생육 특성을 조사하였다. 분리된 두 균주 G5Y와 PW는 혼합배양에 의해서만 PVa를 분해, 자화할 수 있으며, 두 균은 PVA 분해에 있어서 공생관계에 있음을 확인하였다. G5Y 균주와 PW 균주의 형태학적, 생화학적 등 제 특성에 따라 각각 Pseudomonas cepacia와 Pseudomonas pseudomallei로 동정되었다.

• 한국해양바이오학회지
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• 제5권4호
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• pp.15-25
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• 2011

Marine sponges are a rich source of highly diversified bioactive compounds. These medicinally valuable molecules represent extreme physiological and ecological functions in sponges, more presumably involving in the resistance to the feeding by other marine organisms like fish and fouling by barnacles, bacteria, fungi, etc. This feature of attaining resistance made sponges as successful poriferans that possess an impressive array of biological properties ranging from antimicrobial to anticancerous activities. The diversified bioactive principle of sponges might be due to their spacio-temporal distribution and although, the gateway for exploiting the sponges for isolating these distinct, potential molecules is open, suitable technical and methodological approaches are yet to be implemented in order to bring the sponges as successful pharmaceutical leads in the field of marine biotechnology. Despite of the identified difficulties of marine sponge research from past few decades, one should concentrate not only on the basic and applied technical/methodological considerations, but also on the novel strategies like in vitro sponge cell, fragment and whole sponge culture; sponge symbiont cell culture; in situ and ex situ sponge cultivation; and sponge bioreactors and metagenomic approaches, for the successful exploitation of marine sponges towards the novelty in sponge biotechnology. The present review narrates the pros and cons of the nowadays-marine sponge research by focusing on the suggestive ecobiotechnological approaches, based on the latest studies for feasible ecological exploitation and biotechnological application of sponges from the sea.

• Parasites, Hosts and Diseases
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• 제59권5호
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• pp.489-496
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• 2021

Ticks can transmit pathogenic bacteria, protozoa, and viruses to humans and animals. In this study, we investigated the microbiomes of Haemaphysalis longicornis according to sex and life stages. The Shannon index was significantly higher for nymphs than adult ticks. Principal coordinates analysis showed that the microbiome composition of female adult and male adult ticks were different. Notably, Coxiella-like bacterium (AB001519), known as a tick symbiont, was found in all nymphs and female adult ticks, but only one out of 4 male adult ticks had Coxiella-like bacterium (AB001519). In addition, Rickettsia rickettsii, Coxiella burnetii, and Anaplasma bovis were detected in this study.

• Applied Biological Chemistry
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• 제35권1호
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• pp.30-35
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• 1992

Polyvinyl alcohol(PVA)을 탄소원으로 이용할 수 있는 세균 J2W 균주와 J2Y균주를 토양으로 부터 분리하였다. 분리된 이들 균주는 각각 별도의 순수배양으로는 PVA를 이용할 수 없었으나 이들 균주를 혼합배양 하였을 경우는 PVA를 분해 이용할 수 있었으며, 또한 PVA의 중합도(중합도 500, 1500, 2000)에 관계없이 이용할 수 있었다. 이들 두 균주는 다른 PVA 이용 공생균주 Pseudomonas PW와 Pseudomonas G5Y와 재구성하여 혼합배양 하였을 때 J2Y균주와 Pseudomonas PW, J2W 균주와 Pseudomonas G5Y 균주와의 혼합배양에서는 PVA를 이용할 수 있었다. 이들 두 균주는 동정 결과 J2W균주는 Pseudomons pseudomallei 근연균으로, J2Y는 Xanthomonas campestris 근연균으로 동정되었다.

• 한국유기농업학회지
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• 제30권1호
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• pp.103-118
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• 2022

Photorhabdus is a bacterial symbiont of entomopathogenic nematodes of the genus Heterorhabditis in the family Heterorhabditidae. Photorhabdus is known to have nematicidal activity in addition to insecticidal activity. P. temperata isolated from Korean indigenous H. megidis Gwangju strain also produced high control efficacy against root-knot nematode Meloidogyne incognita and root-lesion nematode Pratylenchus penetrans. P. temperata has drawn interest as a potential bionematicide for the control of root-knot nematodes thereby. For the registration as an organic agricultural material, the toxicity of P. temperata was assessed by the acute toxicity test in carp (Cyprinus carpio) and acute oral and dermal toxicity tests in Sprague-Dawley rat (Rattus norvegicus) in compliance with the guidelines of the Rural Development Administration (RDA). In the acute toxicity test in fish, neither lethality nor abnormal responses of carp were observed. Body length and weight of carp and changes in DO concentrations and pH values were not significantly different between the treated group and the untreated control. In the acute oral and dermal toxicity tests, clinical signs, abnormal behavior, mortality, and pathological findings were not observed in all the experimental rats. The weight increment of all rats was normal. Acute toxicity results of P. temperata in fish and rats belonged to categories III, IV, and IV of RDA, respectively. Toxicity results of the present study indicated that P. temperata could be a safe and promising bionematicide against root-knot nematodes and root lesion nematode.

• 한국토양비료학회지
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• 제21권2호
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• pp.141-148
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• 1988

본(本) 시험(試驗)은 우리나라 토착대두근류균(土着大豆根瘤菌)의 균주(菌株) 인식(認識)과 분류(分類)를 위하여 서울농대(農大) 시험포장(試驗圃場)의 13개(個) 대두품종근류(大豆品種根瘤)에서 순수분리(純粹分離)한 대두근류균(大豆根瘤菌) 27개(個)와 본(本) 실험실보유(實驗室保有) 대두근류균(大豆根瘤菌) 6개(個)에 대하여 혈청면역적(血淸免疫學的) 시험(試驗)을 행(行)하였으며 그 결과(結果)는 다음과 같이 요약(要約)된다. 1. 항원조성(抗原組成)이 상이(相異)한 4개(個)의 대두근류균(大豆根瘤菌)에 대하여 얻어진 4가지 항혈청(抗血淸)과 위 33개(個) 대두근류균(大豆根瘤菌)을 tube 응집반응(凝集反應), 응집소(凝集素) 흡착반응(吸着反應) 및 gel 면역확산반응(免疫擴散反應)을 실시(實施)한 결과(結果), 33개(個) 대두근류균중(大豆根瘤菌中) 25개(個)를 4가지 serogroup과 그에 속(屬)한 각(各) serotype으로 구분(區分)할 수 있었다. 2. 33개(個) 대두근류균중(大豆根瘤菌中) Hill, 밀양품종(密陽品種)에서 분리(分離)한 2가지 분리균(分離菌) 및 방사(放射), 장백품종(長白品種)에서 분리(分離)한 2가지 분리균(分離菌), 그리고 팔달(八達), 새알, 장백품종(長白品種)에서 분리(分離)한 4가지 분리균(分離菌)이 혈청면역학적(血淸免疫擧的) 검정(檢定)에 의하여 각각(各各) 동일균주(同一菌株)로 밝혀졌다. 3. 본(本) 실험결과(實驗結果), 혈청면역학적(血淸免疫學的) 방법(方法)에 의하여 우리나라 토착대두근류균(土着大豆根瘤菌)의 균주(菌株) 인식(認識) 및 체계적(體系的)인 분류(分類)와 아울러 균주(菌株)와 대두품종간(大豆品種間)의 친화성(親和性)을 밝히는 것이 가능(可能)하리라 생각된다.

• Parasites, Hosts and Diseases
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• 제61권1호
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• pp.60-71
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• 2023

Cockroaches can cause allergic sensitization in humans via contact with their feces or frass. Antibiotics can affect concentration of major allergen and total bacteria production in German cockroaches (Blattella germanica). This study examined the ability of antibiotic-treated German cockroaches to induce allergic airway inflammation and the effect of antibiotics on their lipopolysaccharide and Bla g1, 2, and 5 expression levels. Specifically, we measured the ability of German cockroach extract (with or without prior antibiotic exposure) to induce allergic inflammation in human bronchial epithelial cells and a mouse model of asthma. Bacterial 16S rRNA and lipopolysaccharide levels were lower in ampicillin-treated cockroaches than in the control group. The Bla g1, Bla g2, and Bla g5 expression in ampicillin-treated cockroaches decreased at both the protein and RNA levels. In human bronchial epithelial cell lines BEAS-2B exposed to the ampicillin-treated extract, expression levels of interleukin-6 and interleukin-8 were lower than that in the control group. The total cell count and eosinophil count in bronchoalveolar lavage fluid was also lower in mice exposed to the ampicillin-treated extract than in those exposed to normal cockroach extract. Mouse lung histopathology showed reduced immune cell infiltration and mucus production in the ampicillin group. Our results showed that ampicillin treatment reduced the symbiont bacterial population and major allergen levels in German cockroaches, leading to reduced airway inflammation in mice. These results can facilitate the preparation of protein extracts for immunotherapy or diagnostics applications.