• The Plant Pathology Journal
• /
• 제26권2호
• /
• pp.121-129
• /
• 2010

We evaluated microbial populations and aflatoxin production in unhulled and white rice from rice processing complexes of the National Agricultural Cooperative Federation in five regions in Korea and identified three predominant Aspergillus species. Fungal and bacterial populations in rice samples were significantly different between regions in 2007. Aflatoxins were also detected and varied at the levels of 2.45 - 3.43 ng per g unhulled rice grain and 1.29 - 2.09 ng per g white rice grain. Unhulled rice generally detected higher level of aflatoxins than white rice regardless of sampling regions; however, no significant differences were found in Anseong and Cheonan in 2005 and Cheonan and Gimpo in 2007. Aflatoxin production between sampling regions was not different regardless of rice type and sampling year. Although the fungal diversity was highly distinct from region to region, three Aspergillus isolates were predominant in the rice samples; thus, representative isolates AC317, AF57, and AF8 were selected and identified based on their morphological and molecular characteristics. Consequently, isolates AC317, AF57, and AF8 were identified as A. candidus, A. flavus, and A. fumigatus, respectively. These fungi can produce mycotoxins that are harmful for consumers and thus it is important to detect and reduce the population of storage fungi in rice.

• 한국식품저장유통학회지
• /
• 제7권1호
• /
• pp.12-18
• /
• 2000

경제적이면서 효과적인 항균성 필름의 생산방법으로서 corona 저려한 저밀도 폴리에틸렌 (LOPE) 필름에 천연항균성 물질을 코팅하는 방법을 개발하고, 이를 딸기의 포장에 적용하였다. 보다 안정한 항균제 코팅 필름의 생산을 위하여 결착제와 함께 코팅한 필름의 생산방법을 검토한 결과, polyamide수지용 과 항균생 물질을 함께 코팅함에 의하여 안정한 코팅을 행성할 수 있었다. 이의 항균성을 미생물 평판 배지 상에서 확인한 결과, 1% 자몽종자추출물로 코팅한 LDPE필름이 Escherichia coli, Staphylococcus aureus, Bacullus subtilis, Bacillus cereus, Leuconostoc mesenteroides, Micrococcus flavus, Saccharomyces cerevisiae 균주에 대해서 항균활성을 보여서 가장 우수하였다. 반면에 10% 대황추출물 코팅한 필름은 오직 M fiav$\mu$s에 대해서만 항균성올 보였고, 10% 대황추출물 코팅 필름은 실험에 사용된 10균주에 대해서 항균성을 나타내지 많았다. 결착제를 이용한 향균제 코팅필름은 딸기의 포장에 적용시 환경기체조절 포장에 작용하였을 때에 포장내에 $O_2$ 1.4-5.5%, $O_2$ 5.7~7.9%의 범위를 형성시켰으며, 비슷한 기체조성을 가진 일반 LDPE필름의 밀봉포장에 비해서 호기성 박테리아와 효모/곰팡이의 생육을 억제하였으나, 부패율 억제에는 뚜렷한 효과를 보이지는 않았다.

• Journal of Forest and Environmental Science
• /
• 제10권1호
• /
• pp.32-37
• /
• 1994

고차기생자(高次寄生者) Tetrastichus sp.는 단기생성(單寄生性) 외부기생자(外部寄生者)로 일차기생자(一次寄生者) Aneristus ceroplastae, Microterys flavus, Coccophagus hawaiiensis의 종령유충(終齡幼蟲)이나 용에 산란(産卵)하였다. 란(卵)부터 성충(成蟲)까지의 발육한계온도(發育限界溫度)와 유효적산온도(有效積算溫度)는 각(各) $9.8^{\circ}C$와 272일도(日度)로 계산(計算)되었다. $25^{\circ}C$의 항온(恒溫), 16시간(時間) 조명조건(照明條件)에서 봉밀원액(蜂蜜源液)을 급여(給與)하며 사육(飼育)한 자(雌) 성충(成蟲)의 평균수명(平均壽命)은 40일(日) 이었다. 성충(成蟲)은 우화(羽化) 24시간후(時間後)부터 산란(産卵)을 시작하여 일생(一生)동안 평균(平均) 220란(卵)을 낳았으며, 50% 누적산란율(累積産卵率)은 산란개시(産卵開始) 14일(日) 후(後)에 달성(達成)되었다. 순번식율(純繁殖率)(Ro)과 세대기간(世代期間)(T), 내적자연증가율(內的自然增加率)(r)은 각(各) 99.6/세대(世代), 32일(日), 0.142/♀/일(日) 이었다.

• 미생물학회지
• /
• 제18권4호
• /
• pp.161-171
• /
• 1980

A mutant strain having increased productivity of both enzymes, protease and amylase, was obtained from A. flavus KU 153, isolatd from South Korea for its high protease production by successive ultra-violet light irradiation, Two glucoamylases from the mutant strain selected were purified from wheat branculture by successive salting out, followed by dialysis and column chromatography, and their characteristics were compared with those of the wild strain. Glucoamylase production of the mutant selected was increased about 3.3 times compared with the wild strain, and 2.1 times compared with the parental strain, ${\alpha}-amylase$ activity of the mutant selected was about 2 times hugher than that of the wild strain or the parental strain. Protease and cellulase productivities of the muant selected were all alike compared with those of the highly proteolytic mutant, the parental strain. Therefore, it was considered that the back mutation on the protease production did not occurred in the formation process of the glucoamylase producing mutant. Total activities of glucoamylase I and II from the mutant selected were 2.86 and 3.65 times higher compared with those from the wild strain, respectively. Considering the optimal pH-thermal stability and Km-Vmax value of glucoamylase I and II from both strains, wild and mutant, it was deduced that the characteristics of glucoamylase I and II from the wild strain did not altered during the mutation process. Therefore, it was concluded that the selected mutant did not induce the formation of another glucoamylase isozyme, or the changes in the characteristics of the glucoamylase, but induce the productivity of the same glucoamylase I and II by the action of regulatory gene.

• 한국잠사곤충학회지
• /
• 제14권1호
• /
• pp.15-24
• /
• 1972

1971년 가을누에 사육기간동안 서울대학교 농과대학 잠실에서 (1) 4가지 중요한 누에 병원체(Aspergillus flavus, Bacillus thuringiensis, Aspergillus Oryzae 및 Isaria farinosa)의 Halamid (Tosylchloramide Sodium) (할라미드; 한국내 등록상품명 하라믿$^{(R)}$ )에 대한 감수성에 관하여 (2) 각 령기에서의 누에 유충에 대한 Halamid의 급성독성에 관하여 (3) 곰팡이로 인한 경화병과 Virus로 인한 농병의 발병에 대한 Halamid의 억제효과와 Halamid의 누에 유충에 대한 만성독성에 관하여 (4) Halamid로서 처리된 누에에서 얻은 생사의 량과 질에 관하여 일련의 실험을 실시하였다. 이번 실험의 결과로서 필자들은 Halamid를 잠실, 잠구 및 잠체 소독약으로서 유효하게 쓸 수 있다는것, 그리고 Halamid는 2%나 3%의 수용액상태로서 누에 유충에 대하여 전령기를 통해서 하루걸러 뿌릴때에 잠체소독약으로서의 효과를 실험한 다른 조건의 경우보다는 더욱 잘 발휘한다는 것을 알아 내었다.

• 한국초지조사료학회지
• /
• 제31권4호
• /
• pp.451-462
• /
• 2011

본 연구는 국내 생산 사료용 볏짚 곤포사일리지의 수확 후 저장기간 동안 생성된 곰팡이 오염도 및 곰팡이 종류를 조사하고 mycotoxin 노출 유해성을 구명하고자 실시하였다. 곰팡이 및 mycotoxin 오염을 조사하기 위하여 곰팡이 발생이 육안 식별이 안 되는 정상적인 것부터 오염이 심한 것까지 다양한 상태의 농가에서 급여하고 있는 33점의 볏짚 곤포사일리지 시료를 수거하여 조사하였다. 오염된 곰팡이는 흰색, 회색, 푸른색 및 검은 갈색 등 다양한 색의 콜로니가 오염된 것을 발견할 수 있었다. 곰팡이 오염도는 평균 $2.1{\times}10^6\;cfu\;g^{-1}$ 가장 높은 오염도는 $9.2{\times}10^8\;cfu\;g^{-1}$까지 발견되었으며, 외관상 곰팡이 오염 식별이 안 되는 정상적인 볏짚 곤포사일리지의 모든 시료에서도 곰팡이 오염이 발견되었다. 본 연구에 사용된 볏짚 곤포사일리지에서 발견된 곰팡이의 종류만도 28가지로 매우 다양하였고, 이들 중 유해 독소를 분비하는 8종의 곰팡이 즉, Aspergillus flavus, Aspergillus fumigatus, Fusarium culmorum, Fusarium verticillioides, Penicillium carneum, Penicillium paneum, Penicillium roqueforti, Penicillium viridicatum이 발견되었다. 특히, 가장 많이 분리된 곰팡이는 Penicillium sp.로 이중에서도 P. paneum이 시료의 42%에서, 다음으로 Aspergillus sp. (A. flavus, A. fumigatus)는 시료의 21%에서 발견되었다. 볏짚 곤포사일리지 시료의 42%가 mycotoxin에 오염되어 있었고, 2개 이상의 mycotoxin에 오염된 것은 12%, 그리고 3개 이상 mycotoxin에 오염된 것은 3%였다. Mycotoxin 중 aflatoxin ($B_1$, $B_1$, $G_1$, $G_2$)과 fumonisin ($B_1$, $B_2$)은 발견되지 않았지만, ochratoxin A (1.0~5.8 ug/kg), deoxynivalenol (DON, 156.0~776.7 ug/kg) 및 zearalenone (ZON, 38.0~750.0 ug/kg)이 오염되어 있었다. 따라서 본 연구결과는 볏짚 곤포사일리지가 곰팡이 및 mycotoxin의 유해성에 노출되어 있음을 시사하는 바 앞으로 폭넓은 연구와 함께 mycotoxin으로 인한 가축의 피해를 줄여주기 위한 다각적인 노력이 필요하였다.

• 한국미생물·생명공학회지
• /
• 제10권2호
• /
• pp.101-108
• /
• 1982

인삼extract와 인삼saponin의 세균 세포 증식에 대한 영향은 세균의 종 및 인삼 성분농도에 따라 차이가 있었다. Serratia marcescens, Aevobacter aerogenes등은 인삼extract 0.1%첨가 농도에서 최대 증식을 나타내었으나 1%, 농도 이상에서는 증식이 억제되었으며 Staphylo. coccus aureus, Escherichia coli등은 1% 농도에서 최대 증식을 나타내었으나 5% 농도에서는 증식이 억제되었다. 인삼 saponin 0.002 %, 농도에서는 Micrococcus flavus, Aerobacter aerogenes등은 증식이 약간 촉진되나 0.02%, 이상의 농도에서는 증식이 현저히 억제되고 Serratia속 세균에서는 인삼saponin이 증식 억제 인자로 작용하였으나 Erwinia aroideae, Sarcina margtnata등에서는 세균 증식에 무관한 것으로 나타났다. 이러한 인삼 saponin이 나타내는 항균활성의 원인 물질은 ginsenoside Rg$_1$이었다.

• Mycobiology
• /
• 제39권3호
• /
• pp.206-218
• /
• 2011

The seed-borne mycoflora of sorghum and foxtail millet collected from different growing areas in South Korea were isolated and taxonomically identified using dry inspection, standard blotter and the agar plate method. We investigated the in vitro and in vitro germination rates of disinfected and non-disinfected seeds of sorghum and foxtail millet using sterilized and unsterilized soil. The percent recovery of seed-borne mycoflora from the seed components of sorghum and foxtail millet seeds was determined and an infection experiment using the dominant species was evaluated for seedling emergence and mortality. A higher number of seed-borne fungi was observed in sorghum compared to that of foxtail millet. Eighteen fungal genera with 34 fungal species were identified from the seeds of sorghum and 13 genera with 22 species were identified from the seeds of foxtail millet. Five dominant species such as Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme and Phoma sp. were recorded as seed-borne mycoflora in sorghum and 4 dominant species (Alternaria alternata, Aspergillus flavus, Curvularia lunata, Fusarium moniliforme) were observed in foxtail millet. The in vitro and in vitro germination rates were higher using disinfected seeds and sterilized soil. More seed-borne fungi were recovered from the pericarp compared to the endosperm and seed embryo. The percent recovery of seed-borne fungi ranged from 2.22% to 60.0%, and Alternaria alternata, Curvularia lunata and 4 species of Fusarium were isolated from the endosperm and embryo of sorghum and foxtail millet. Inoculation of the dominant seed-borne fungi showed considerable mortality of seedlings. All the transmitted seed-borne fungi might well be a primary source of infection of sorghum and foxtail millet crops.

• 한국작물학회지
• /
• 제68권3호
• /
• pp.175-187
• /
• 2023

Peanuts, also known as groundnuts (Arachis hypogaea L.), are globally recognized as a vital oilseed crop. Peanuts are rich in proteins (e.g., arginine), oils (e.g., oleic acid and linoleic acid), fiber, vitamins (e.g., niacin and tocopherol), and carbohydrates and are consumed worldwide. However, the presence of aflatoxin (AF) has garnered substantial attention since its initial discovery as the causative agent of Tukey's X disease in the United Kingdom in 1960. Among the 18 aflatoxins identified, aflatoxin B₁ (AFB₁) has the highest toxic activity and causes hepatocellular carcinoma. It is classified as Group I by the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO). The present study was conducted to evaluate aflatoxin B₁ resistance of 102 peanut accessions and select putative aflatoxin B₁-resistant peanut accessions to aflatoxin B₁. One hundred and one Korean germplasms harvested in 2020 were inoculated with A. flavus to identify aflatoxin-resistant cultivars, and the aflatoxin B₁ concentration was measured using an ultra-performance liquid chromatography-photodiode array detector. Twenty-six accessions with aflatoxin B₁ concentrations lower than those of the check plant 55-437 were chosen for the development of aflatoxin-resistant varieties in Korea. As Korean aflatoxin-resistant varieties have not yet been developed, the findings of the present study are expected to provide useful information for the development of aflatoxin-resistant cultivars.

• Applied Microscopy
• /
• 제18권2호
• /
• pp.1-20
• /
• 1988

The species of the slug used in the experiment is Limax flavus L. For identifying the chemical characteristics of the epidermis, granules and mucus-producing cell of this animal is examined with methylene blue-basic fuchsin double stain and PAS-alcian blue reagent. For the ultrastructural research of the epidermal free surface, the epitheial cell and the parenchymal cell are used with scanning electron microscope and transmission elec-tron microscope respectively. I . Epidermal tissue The epidermal tissue of the slug is observed being divided into the dorsal and the ventral side(toot pad) respectively. 1) Dorsal epidermal tissue The dorsal epidermis of the slug is constituted with the simple columnar epithelium and the microvilli are compacted on the epidermal free surface. Two different types of the secretory granules of the neutral and the acid mucus are observed between the epithelial cells, and the neutral mucous granules are highest electron-dense but the acid mucous granules are observed to be electron-lucent. 2) Foot epidermal tissue The Foot epidermis is formed with the taller simple columnar epithelium than the dorsal epidermis and these cells have both a large number of the microvilli and a few number of the large villi. The secretory granules of three different types, which are acid, neutral and mixed mucous granule of two different types are observed between the epithelial cells. The neutral mucous granules are highest electron dense but the acid mucous granules are observed to be electron-lucent. II . Mucous granule-producing cell and mucus-producing cells Seven different types of the granules-producing cell and the mucus-producing cells are observed between the parenchyma. 1) A-type of acid mucous granule-producing cell The electron-lucent granules are largely occupied in the cytoplasm of these cells and then the granules are surrounded by irregular membrane. These electron-lucent granules exhibit alcianophilia with PAS-alcian blue reaction, so these granules are certified to be acid mucopolysaccharide. 2) B-type of acid mucus-producing cell The nucleus and the cytoplasm of these cells are pushed by the acid mucus of the electron-lucent toward the cell membrane. This mucus has been confirmed to be the acid mucopolysaccharide with PAS-alcian blue reagent. 3) A-type of neutral mucous granule-producing cell These cells contain the electron-dense round granules with approximately $1{\mu}m$ in diameter, which exhibit strongly PAS-positive reaction. These granules are confirmed to be the neutral mucoplysaccharide. 4) B-type of neutral mucous granule-producing cell These cells contain two different types of electron dense granules and electron-lucent granules; The former exhibits to be strongly PAS-positive and the latter to have alcianophilia reaction respectively. 5) C-type of neutral mucus-producing cell These cells are similar to the shape and the size of the B-type of mucus-producing cell but these two different types of cells are stained with reversing properties to each other. The mucus of the C-type cell that electron-lucent is largely occupied in the cytoplasm that exhibits strongly PAS-positive reaction. 6) D-type of neutral mucous granule-producing cell These cells contain round granules about $1{\mu}m$ in size which are observed to be medium electron-dense granules and those granules are stained brightly red with PAS-weak positive reaction. The granules are certified to be neutral mucopolysaccharide. 7) E-type of neutral mucous granule-producing cell These cells are similar to the shape and the size of the D-type of neutral mucous granule-producing cell. These cells contain a large number of granules with about $1{\mu}m$ in diameter showing electron-lucent and then granules are seen to be PAS-weak positive reaction. III. Parenchyma The clear cell and dark cell are found in the parenchyma of the Limax flavus L. 1) Clear cell These cells are round formed and the nucleus of the cells are larger than cytoplasm. These cells which have the electron-lucent cytosol possess poorly developed organelles. 2) Dark cell These cells are found to be dark cells due to high electron-density, which exhibit strongly methylene-blue reaction from double stain of methylene blue-basic fuchsin.