• Journal of Life Science
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• v.21 no.10
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• pp.1481-1486
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• 2011

Spent mushroom substrate (SMS) is a by-product remained after a crop of mushrooms. About seven thermophilic strains were isolated from SMS (Flammulina velvtipes). Among them, one isolate, designated UJ03, showed the antifungal activity against Aspergillus flavus and Aspergillus ochraceous producing mycotoxin on PDA medium, potentially. The strain UJ03 produced cellulase and xylanase as extracellular hydrolases. The strain UJ03 was identified as a member of the genus Bacillus by biochemical characteristics using Bacillus ID kit and VITEK 2 system. Comparative 16S rDNA gene sequence analysis showed that strain UJ03 formed a distinct phylogenetic tree within the genus Bacillus and was most closely related to Bacillus amyloliquefaciens with sequence similarity of 98.9%. On the basis of its physiological properties, biochemical characteristics and phylogenetic distinctiveness, strain UJ03 was classified within the genus Bacillus, for which the name Bacillus sp. UJ03 is proposed. The antifungal compound from Bacillus sp. UJ03 was similar to lipopeptide iturin A of Bacillus sp.

• Journal of Mushroom
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• v.9 no.4
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• pp.180-185
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• 2011

Spent mushroom substrates (SMS) is a by-product remaining after a crop of mushrooms. About four surfactin-producing strains were isolated from SMS (Pleurotus eryngii). Among of them, one isolate, which designated to YJ07, potentially showed the antifungal activity against Aspergillus flavus and Aspergillus ochraceous producing mycotoxin on PDA medium. The biochemical characteristics of the strain YJ07 was similar with Bacillus subtilis and Bacillus amyloliquefaciens by Bacillus ID kit and VITEK 2 system. Comparative 16S rDNA gene sequence analysis of the strain YJ07 also showed that the strain YJ07 was most closely related to Bacillus amyloliquefaciens with sequence similarity of 99.5%. On the basis of their biochemical characteristics and phylogenetic distinctiveness, the strain YJ07 was classified within the genus Bacillus as Bacillus amyloliquefaciens YJ07. The antifungal compound from B. amyloliquefaciens YJ07 was similar to lipopeptide surfactin from Bacillus subtilis by TLC and HPLC analysis.

• Journal of Food Hygiene and Safety
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• v.5 no.3
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• pp.131-138
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• 1990

Aflatoxins is a chemically diverse group of toxic secondary metabolites that are produced by fungi and often occur in agricultural commodities. Because of their wide range of toxic effects, Aflatoxins cause severe economic losses to farmers and livestock producers and pose a health to human consuming contaminated foods. Long term prospects for biotechnological control of Aflatoxins require elucidation of the specific steps and regulation of their biosynthetic pathways . Aflatoxin determinations can be approached many ways. It is essential to safely handle all experimental materials associated with aflatoxin analysis or aflatoxigenic fungi Visual screening of suspect samples, base on the presence of conidial head of the aspergillus flavus group, and screening samples for the presence of bright greenish yellow flourescence are not chemical tests and such screening techniques may allow aflactoxin contaminated lots into commerce. Microcolumn screening procedures should always be used in conjunction with a quantitative method. Several thin layer chromatography(TLC) and high performance liquid chromatography(HPLC) methods are suitable for quantitation and are in general use. Immunochemical Methods such as the ELISA or affinity column chromatography methods are being rapidly developed. The chemical and immunochemical methods can be reliable if care is taken, using suitable controls and personnel that are well trained . All analytical laboratories should stress safety and include suitable analytical validation procedure. Especially a worldwide enquiry was undertaken in recent to obtain up-to-date information about aflatoxin legislation in as many countries of the world as possible. The information concerns aflatoxin in foodstuffs. aflatoxin MI in dairy products, aflatoxins in animal feedstuffs. Limits and regulations for aflatoxin have been expended in recent with more countries having legislation on subject, more products, and more aflatoxins covered by this legislation.

• Korean Journal of Microbiology
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• v.9 no.4
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• pp.155-162
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• 1971

A comparison of dextrinogenic amylase activities in the Asp. niger group was made with their crude and ethanol dialized enzymes before and after heating at high temperature (60-$65^{\circ}C$). The results obtained are as follows ; 1. THe dextrinogenic amylase activity of crude enzymes of Asp. kawachii and Asp. foetidus was strong, but Asp. phoernicis, Asp. carbonarius and Asp.japonicus showed weak activity. The others showed medial grades of activity. 2. The ethanol dialized enzymes of Asp. kawachii, Asp. foetidus and Asp. japonicus was very sesitive to high temperature (60 or $65^{\circ}C$) and their enzymatic activities were diminished greatly. The others did not show diminution of enzymatic activity at 60 or 65.deg.C, but diminished greatly at 70 or $75^{\circ}C$. 3. The ethanol dialized enzymes of the Asp.niger group heated to 65.deg.C was more sensitive at pH 6.0 and 6.5 than at pH 4.5, 5.0 and 5.5. 4. Tested strains in the Asp.niger group were subdivided into 4 subgroups by their dextrinogenic amylase activities before and after heating at 60 or $65^{\circ}C$. The first group showed a medial grade of activity before heating and no diminution of their enzymatic activities after heating. Asp. niger, Asp.pulverulentus, Asp. awamori and Asp. usmii were included in this group. The second group had strong enzymatic activity before heating, but diminished greatly after heating. Asp rawachii and Asp. phoenicis were included in this group. The fourth group showed very weak enzymatic activity before heating, and was inactivated easily by heating. Asp.oryzae of the Asp. flavus group showed a very strong dextrinogenic amylase activity before heating. After the heat treatment, however, its enzymatic activity was diminished greatly.

• Microbiology and Biotechnology Letters
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• v.44 no.1
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• pp.98-105
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• 2016

The presence of bacterial strains showing antagonistic activity to common pathogens found in a variety of fermented foods in Korea was explored. A bacterium inhibiting the growth of pathogens such as Aspergillus terreus (KCTC6178), A. flavus (KCTC6984), Staphylococcus aureus (KCCM12214), Escherichia coli O157:H7 (KCCM40406), Bacillus cereus (KCTC1012), Cryptococcus neoformans (ATCC208821), Salmonella typhimurium (ATCC19430), and Listeria monocytogenes (KCTC3569) was isolated from Makgeolli, a Korean traditional rice wine. The strain showing high antipathogenic activity was identified as B. amyloliquefaciens based on the nucleotide sequence of the 16S ribosomal RNA gene. Compared with B. amyloliquefaciens KCTC1660, whose genome has been sequenced, the isolate exhibited significantly low activities of starch-degrading enzymes and high resistance to high temperature and low pH.

• Journal of Sericultural and Entomological Science
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• v.24 no.1
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• pp.32-38
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• 1982

The study has been carried out to investigate a possibility to control the pine needle gall midge, Thecodiplosis japonensis Uchida et Inoue, by microbial pathogens as one of the microbial control measures. The samples were collected at Kocheon-Ri in the suburbs of Suweon city where were heavily damaged by this pest. Microorganisms were isolated from the both of diseased larvae and baiting method of soil microbes. In addition to, several species of the silkworm mucardine diseases were isolated for their infectivity of these fungi to the larvae of pine needle gall midge. Six species of fungi, Aureobasidium pullulans, Ascochyta sp, Verticillium psalliotae, Streptomyces sp., and two species of Aspergillus were isolated from the galls and soils, five species of muscardine diseases, Isaria farinosa, Spicaria pracina, Oospora destructor, Aspergillus flavus and A. oryzae were also identified from the silkworm corpse collected in the silkworm rearing farmers. Total of eleven species of fungi identified from the both of the larval of pine needle gall midge and silkworm larvae were tested for their pathogenecity to the larvae of pine needle gall midge. All of eleven species of fungi identified showed a considerable infectivity to the larvae. Twenty nine different kinds of bacteria were isolated from the both of diseased larvae and infested soils through the direct planting for the larvae and streaking for the corpse. The infectivity test is in progress. However two kinds of bacteria were recognized to be pathogenic to the larvae tested.

• Journal of Life Science
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• v.19 no.1
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• pp.65-74
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• 2009

The objective of this study was to examine the effects of steam flaking treatment of corn grains imported from USA and India on in vitro gas production, microbial growth and contents of aflatoxin $B_1$ and ochratoxin A. Each treatment was composed of total 4 treatments including (1) USCW (US com-whole type), (2) USCF (US corn-flaked type), (3) IDCW (India corn-whole type) and (4) IDCF (India orn-flaked type) with 4 replications $\times$ 6 incubation times (3, 6, 9, 12, 18 and 24 hr). Mycotoxin (aflatoxin $B_1$ & ochratoxin A) contents in test corns tended to increase gradually with increasing logistics periods from the harbor, hopper, silo to processing line. The contents of aflatoxin $B_1$ in India corn (IDCW) and US corn (USCW) were 11.71 and 1.78 ppb, respectively when measured at the hopper. After steam flaking, both contents of aflatoxin $B_1$ in USCW and IDCW were 0.00 ppb. It means that Aspergillus flavus could be decreased by steam flaking. However, this trend was not observed in ochratoxin content. The gas production rate of USA corns (USCW & USCF) was significantly (p<0.05) higher than India corns (IDCW & IDCF), and that of steam flaked corns (USCF & IDCF) was higher $1.5{\sim}2%$ than whole corns (USCW & IDCW) after 3 hr incubation in in vitro experiment. pH value was optimally maintained for microbial growth during whole incubation times with the value of 6.05 to 6.54, and was not significantly different between treatments, but USCF was somewhat lower than other treatments. pH value decreased following 12 hr of incubation but gas production increased rapidly during the same period. In addition, in vitro microbial growth rates also increased with up to 18 hr of incubation period, thereafter experienced a decrease with extended incubation time. In conclusion, US corn was superior to India corn by origin based on the results of in vitro and mycotoxin contents. And steam flaking process of imported corns tended to decrease mycotoxin contents such as aflatoxin $B_1$ and ochratoxin A as well as improve in vitro gas production and microbial growth rates.

• Advances in Traditional Medicine
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• v.5 no.4
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• pp.308-315
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• 2005

Aflatoxin contamination is a major problem in several food crops. Aflatoxin, a mycotoxin, produced by Aspergillus flavus has gained immense concern in the scientific world because of its tremendous harmful effects. The study was focused to see the effect of oil and aqueous extract of neem (Azadirachta indica) seeds on the growth of Aspergillus and production of aflatoxin by the mold. Various amounts of neem oil $(5\;-\;50\;{\mu}l/ml)$ and aqueous extract of neem (5 - 50 mg/ml) were used both in the broth as well as the solid medium. Fungistatic (MIC) and minimal fungicidal concentrations (MFC) were found to be $10\;{\mu}l/ml$ and $50\;{\mu}l/ml$ respectively for neem seed oil. At the concentration of $5\;{\mu}l/ml$ neem oil and 5 mg/ml of aqueous extract, a significant decrease in the aflatoxin content was found in broth medium. Aflatoxin production was totally inhibited at $50\;{\mu}l/ml$ and 50 mg/ml for neem oil and aqueous extract of neem respectively, in both treatments. There was significant inhibition of mycelium dry weight by the neem seed oil. Mycelial growth was totally inhibited at $20\;{\mu}l/ml$ of neem seed oil concentration in broth, whereas it was not affected at all by aqueous extract. It can therefore be inferred that the oil and extract from the neem seed leads to inhibition of aflatoxin production while neem seed oil also significantly inhibits the mycelial growth. Neem seed oil thus can be used as potent, natural and easily available anti-aflatoxigenic agent.

• The Journal of the Korean Society for Microbiology
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• v.22 no.1
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• pp.15-22
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• 1987

Pulmonary fungal infection has been investigated in patients with healed or active pulmonary tuberculosis or other lung diseases by demonstrating serum precipitating antibodies to the various fungal antigens and by isolating the related fungi from sputums or other clinical specimens. Out of 1,192 suspected patients, 405(34.0%) showed precipitin bands on immunodiffusion tests and the related fungi have been demonstrated in sputums or other specimens of 79.5% of them(327) whose specimens had been cultured. Three patients did not have precipitating antibodies to any fungal antigen, but the same fungus was repeatedly isolated from sputums of two patients for over one year of period and from open lung biopsy specimen in the other patient. Most commonly involved species in pulmonary infection were A. fumigatus(70.3%) and C. albicans (at least 23.8%), followed by A. flavus, P. boydii, A. nidulans, etc. Out of fungi isolated from individuals(459), who were apparently not infected with fungi, molds were 66.0% and the rest, yeasts. Most commonly encountered molds were aspergilli(31.7%), followed by penicilli(16.3%), Cladosporium spp.(2.8%), Fusarium spp.(2.2%), etc. C. albicans(16.6%) was of course most common yeast in human sputums and the other species were seen in few.

• Applied Biological Chemistry
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• v.13 no.3
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• pp.243-256
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• 1970

Nowadays, the damages caused by molds in cotton textile goods becomes influential. In our country, however, the relations between cotton goods and molds are not investigated and studied in detail. Two hundred and fifty seven kind of mold's samples were collected in ninety places through the whole country. The molds samples are mainly gathered according to each regions and seasons from molded cotton textiles. Out of this samples, we isolated six hundred and seventy two strains of molds and the results of isolation are following. 1. The distributed molds were Aspergillus sp., Rhizopus sp., Penicillium sp., etc. among them Aspergillus sp. were most widely distributed, and next were Rhizopus sp., Penicillium sp. etc. 2. The distribution of Aspergillus sp. abounded peculiarly in the dry season, while Rhizopus sp. in the rainy season. 3. The C.M.C, descomposing enzymes forming activity on molds were greatly concerned with intensity damage of cotton textile goods. 4. The formation of C.M.C. decomposing enzyme was only influenced by physiology of each strains. 5. Regarding to the growth. a. The molds which were saprophyting on the cotton textile goods were indicated vigorous growing. b. Among isolated six hundred and seventy two strains, there were above a hundred strains which produced pigment and nearly half of them fifty nine strains were Aspergillus sp. 6. Twenty one strains in isolated six hundred and seventy two strains were indentified which can heavily damage upon cotton textile. As a results of indentification of the selected strains, the following species was abtained, Aspergillus sydowi, wentii, niger, luchuensis, flavus, fumigatus, nidulans, Penicillium frequentants, roqueforti, chrysogenum, albicans, Rhizopus oligosporus, delemar, Mucor rouxii, mucedo, Neurospora sitophila, Monilia variabilis, fructigena, Cladsporium hurbarum and Aspergillus spp. Mucor spp.