• Mycobiology
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• 제31권4호
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• pp.183-190
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• 2003

Five cereal grains(wheat, barley, rice, maize and sorghum) were collected from three Egyptian provinces known to be grain producers(Daqahlia, Gharbia and Kafer el-Sheikh). Two species of Alternaria(A. raphani and A. tenusinae); two species of Aspergillus(A. flavus and A. niger); one species of Cunninghamella(C. elegans); one Dreschslera species(D. myakt); three Fusarium species(F. graminearum, F. moniliform and F. solani); one Rhizopus species(R. stolonifer) and two species of Penicillium(P. digitatum and P. notatum) were isolated from the grains. The densities of these fungi and their frequencies of occurrence have been investigated. All the fungal isolates were tested for the production of toxic metabolites in culture media and the percentages of toxigenic isolates were calculated. The biological assay of the toxigenic fungal isolates showed significant variations in toxigenic activity. Thin layer chromatography revealed that the most active isolate produces moniliformin in culture media. The effect of culture conditions on the production of moniliformin was studied.

• The Plant Pathology Journal
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• 제31권4호
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• pp.334-342
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• 2015

Two fumonisin-nonproducing strains of Fusarium verticillioides and their fumonisin producing progenitors were tested for aggressiveness toward maize, sorghum, rice, and beetroot seedlings grown under greenhouse conditions. None of the plants showed obvious disease symptoms after root dip inoculation. Fungal biomass was determined by species-specific real-time PCR. No significant (P = 0.05) differences in systemic colonization were detected between the wild type strains and mutants not producing fumonisins. F. verticillioides was not detected in any of the non-inoculated control plants. The fungus grew from roots to the first two internodes/leaves of maize, rice and beet regardless of fumonisin production. The systemic growth of F. verticillioides in sorghum was limited. The results showed that fumonisin production was not required for the infection of roots of maize, rice and beet by F. verticillioides.

• Journal of Microbiology and Biotechnology
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• 제26권5호
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• pp.967-974
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• 2016

Zearalenone (ZEA) is an estrogenic mycotoxin that is produced by several Fusarium species, including Fusarium graminearum. One of the ZEA biosynthetic genes, ZEB2, encodes two isoforms of Zeb2 by alternative transcription, forming an activator (Zeb2L-Zeb2L homooligomer) and an inhibitor (Zeb2L-Zeb2S heterodimer) that directly regulate the ZEA biosynthetic genes in F. graminearum. Cyclic AMP-dependent protein kinase A (PKA) signaling regulates secondary metabolic processes in several filamentous fungi. In this study, we investigated the effects of the PKA signaling pathway on ZEA biosynthesis. Through functional analyses of PKA catalytic and regulatory subunits (CPKs and PKR), we found that the PKA pathway negatively regulates ZEA production. Genetic and biochemical evidence further demonstrated that the PKA pathway specifically represses ZEB2L transcription and also takes part in posttranscriptional regulation of ZEB2L during ZEA production. Our findings reveal the intriguing mechanism that the PKA pathway regulates secondary metabolite production by reprograming alternative transcription.

• Applied Biological Chemistry
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• 제33권2호
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• pp.169-173
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• 1990

곡류 등에 오염되어 황색 독소성분인 skyrin을 생합성하는 Penicillium islandicum 배지에 grapefruit 종자로부터 추출한 천연유기 복합물인 DF-100을 처리하여 곰팡이 생육 및 skyrin 생성을 저해하는 효과를 볼 수 있었다. DF-100 500ppm 농도로 Penicillium islandicum의 생육을 91% 저해하였고 750ppm 농도에서 곰팡이 생육을 완전히 저해하였으며 500ppm농도로 skyrin생성을 완전히 저해하였다. skyrin 생합성경로를 고려할 때 DF-100은 낮은 농도에서 emodinanthrone으로부터 emodin을 거쳐 skyrin으로 전환되는 효소 반응계와 skyrinanthrone으로 진행하는 반응단계를 저해하는 것으로 밝혀 졌다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.85.1-85
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• 2003

In most ascomycetes, a single mating type locus, MAT, with two alternate forms (MAT1-1 and MAT1-2) called idiomorphs, controls mating ability. In heterothallic ascomycetes these alternate idiomorphs reside in different nuclei. In contrast, most homothallic ascomycetes carry both MAT1-1 and MAT1-2 in a single nucleus, usually closely linked. An example of the latter is Gibberella zeae, a producer of mycotoxins such as trichothecene and zearalenone that threaten human and animal health. We asked if G. zeae could be made strictly heterothallic by manipulation of MAT. Targeted gene replacement was used to differentially delete MAT1-1 or MAT1-2 from a wild type haploid MAT1-1 MAT1-2 strain, resulting in MAT1-1；mat1-2, mat1-1；MAT1-2 strains that were self-sterile, yet able to cross to wild type testers and more importantly, to each other. These results indicated that differential deletion of MAT idiomorphs eliminates selfing ability of G. zeae, but the ability to outcross is retained. To our knowledge, this is the first report of complete conversion of fungal reproductive strategy from homothallic to heterothallic by targeted manipulation of MAT. Practically, this approach opens the door to simple and efficient procedures for obtaining sexual recombinants of G. zeae that will be useful for genetic analyses of mycotoxin production and other traits, such as ability to cause disease.

• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1397-1404
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• 2014

A few starters have been developed and used for doenjang fermentation but often without safety evaluation. Filamentous fungi were isolated from industrial doenjang koji, and their potential for mycotoxin production was evaluated. Two fungi were isolated; one was more dominantly present (90%). Both greenish (SNU-G) and whitish (SNU-W) fungi showed 97% and 95% internal transcribed spacer sequence identities to Aspergillus oryzae/flavus, respectively. However, the SmaI digestion pattern of their genomic DNA suggested that both belong to A. oryzae. Moreover, both fungi had morphological characteristics similar to that of A. oryzae. SNU-G and SNU-W did not form sclerotia, which is a typical characteristic of A. oryzae. Therefore, both fungi were identified to be A. oryzae. In aflatoxin gene cluster analysis, both fungi had norB-cypA genes similar to that of A. oryzae. Consistent with this, aflatoxins were not detected in SNU-G and SNU-W using ammonia vapor, TLC, and HPLC analyses. Both fungi seemed to have a whole cyclopiazonic acid (CPA) gene cluster based on PCR of the maoA, dmaT, and pks-nrps genes, which are key genes for CPA biosynthesis. However, CPA was not detected in TLC and HPLC analyses. Therefore, both fungi seem to be safe to use as doenjang koji starters and may be suitable fungal candidates for further development of starters for traditional doenjang fermentation.

• 한국동물위생학회지
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• 제42권3호
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• pp.127-133
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• 2019

The purpose of this study was to investigate the contamination level of representative mycotoxins that have adverse effects on livestock by using LC-MS/MS method and to utilize the results as basic data for the establishment of quality control system for feed, and to provide information on production and storage. A total of nine mycotoxins, including aflatoxin $B_1$, aflatoxin $B_2$, aflatoxin $G_1$, aflatoxin $G_2$, ochratoxin A, fumonisin $B_1$, fumonisin $B_2$, deoxynivalenol (DON), zearalenone (ZEN) were simultaneously analyzed in LC-MS/MS under ESI positive mode. Fumonisin $B_1$ and fumonisin $B_2$ were detected from 3 cases of 75 forage produced in Incheon area, the detection rate was 4.0%. The detection concentration was 0.01~0.02 mg/kg, which was lower than the domestic recommended limit. Fumonisins were detected in a slightly different manner from the results of mycotoxin studies reported in Korea, which is attributed to the high temperature and dry summer weather of the year. The result of LC-MS/MS method performance of 9 mycotoxins, the recovery of DON was quite low as $41.53{\pm}3.91%$ that is not suitable for simultaneous analysis. This is probably due to that the extract solution used in this study was not suitable for the extraction of DON, along with the characteristics of a very dry forage. For the study of mycotoxins in Incheon area forage for the first time, further investigation is needed for the safe supply of livestock products.

• Asian-Australasian Journal of Animal Sciences
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• 제19권1호
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• pp.72-79
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• 2006

1,225 healthy day-old avian broiler chicks were used to investigate the effects of activated charcoal (AC, made from willow tree), hydrated sodium calcium aluminosilicates (HSCAS) and esterified glucomannan (EGM) supplementation on broiler performance, blood profiles and meat characteristics when less moldy or moldy corn was included to formulate seven isocaloric and isonitrogenous diets: Positive Control (less moldy corn diet, PC), PC+2% AC, Negative Control (moldy corn, NC), NC+0.05% EGM, NC+0.1% EGM, NC+0.5% HSCAS and NC+1% AC. PC+2% AC resulted in lower growth rate, poorer feed conversion ratio (FCR), more leg problems and higher mortality of birds than those fed PC diet (p<0.05). Inclusion of 0.05% EGM, 0.1% EGM, 0.5% HSCAS and 1% AC in NC diet did not improve average daily weight gain (ADG) or affect feed intake of birds during the first or the second three-week periods. However, 0.05% EGM tended to (p>0.05) and 0.1% EGM significantly (p<0.05) improved FCR during the first three-week period. Breast meat of NC birds had higher Minolta $L^*$ values (white) but lower $a^*$ (reddish) and $b^*$ (yellowish) values (p<0.01) than the PC birds. Addition of 0.05% EGM and 0.1% EGM in NC diet reduced the $L^*$ values (p<0.05), improved $a^*$ and $b^*$ values (p<0.05) of breast meat of birds fed NC diet, but had no effect on meat color when 0.5% HSCAS or 1% AC was included (p>0.05). Relative weight of liver to body was reduced by feeding NC diet (p<0.05) and could not be normalized by different mycotoxin adsorbents (p>0.05) to the ratio of the PC birds. Relative weight of cholecyst of NC birds was increased compared with PC birds and could only be normalized by addition of 0.05% EGM and 1% AC (p<0.05) in NC diet. NC birds had lower serum albumin level than the PC birds (p<0.05) and addition of 0.05% EGM or 1% AC in NC diet did normalize serum albumin level. Addition of 0.5% HSCAS in NC diet further reduced serum albumin, globulin, total protein and uric acid levels (p<0.05). It was concluded that lower FCR during the first three-week period of growth and deterioration of meat quality observed in bird fed moldy corn with moderate T2 and fuminisin contamination and damaged nutrients and pigment availability, might be improved by dietary supplementation of 0.05% to 0.1% EGM, but not by 1% AC or 0.5% HSCAS supplementation.

• Applied Biological Chemistry
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• 제25권3호
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• pp.189-196
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• 1982

우리나라에 유통(流通)되고 있는 시판사료(市販飼料)(수집시료(蒐集試料) 72종(種)) 중(中) 미생물분포(微生物分布)와 수분함량(水分含量) 그리고 곰팡이 독소생성(毒素生成)에 대(對은)하여 검토(檢討)하고 다음과 같은 결과(結果)를 얻었다. 시판사료(市販飼料) 72종(種)의 수분함량(水分合量) $11.2{\sim}l5%$ 범위이었다. 총세균수(總細菌數)는 1g 당(當) $1.8{\times}10^2{\sim}2.4{\times}10^6$개(個)이었다. 대장균군수(大腸菌群數)는 1g당(當) $9{\sim}6.3{\times}20^5$개(個)이었고 주(主)로 토양유래(土壤由來)의 Enterobacter와 Klebsiella로 구성되었으며, Escherichia coli는 1%이하(以下)로 검출(檢出)되었고, 대부분(大部分)의 사료(飼料)는 이들 균오염도(菌汚染度)에 문제성이 없으나 유동 broiler 용사료(用飼料)에서는 분뇨성 유래(由來) Escherichia coli오염도(汚染度)가 커서 문제성으로 주목(注目)할만하다. 일반사상균수(一般絲狀菌數)는 수집시료(蒐集試料)의 약(約) 45%가 검출한계(檢出限界) 이상(以上)이었고 기외오염사료(其外汚染飼料)는 1g당(當) $5.9{\times}10^2{\sim}4.5{\times}10^5$이었다. 내삼투성(耐?透性) 사상균(絲狀菌)은 전수집시료(全蒐集試料)에서 검출(檢出)되었으며 1g당(當) $2.5{\times}10{\sim}3.5{\times}10^5$ 범위에 있었고, 주(主)로 Aspergillus glaucus군(群)에 속(屬)하는 Asp. amsteldami, Asp. ruber, Asp, ochraceus와 기타 소수(小數)의 Asp. versicolor, Penicillium sp. 로 구성되어 있다. Mycotoxin 생산균인 Asp. flavus, Asp. candidus Asp, ochraceus 등이 오염(汚染)은 되었었으나 그 분포(分布)와 생육밀도(生育密度)로 보아 주목(注目)할만한 것은 못되었다. 전수집사료(全蒐集飼料)에 대(對)하여 Mycotoxin을 검색(檢索)한 바 확인(確認)할 수 없었다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권4호
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• pp.505-513
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• 2018

Objective: This experiment investigated the effects of aflatoxin B1 (AFB1) alone or mixed with ochratoxin A (OTA) and/or zearalenone (ZEA) on the metabolism, immune function, and antioxidant status of dairy goats. Methods: Fifty lactating Laoshan dairy goats were randomly assigned to one of five treatment groups (n = 10) for 14 days. Goats were fed no additive (control) or administered with $50{\mu}g\;AFB1/kg$ dry matter (DM) (AFB1), $50{\mu}g\;AFB1/kg$ $DM+100{\mu}g\;OTA/kg$ DM (AFB1+OTA), $50{\mu}g\;AFB1/kg$ $DM+500{\mu}g\;ZEA/kg$ DM (AFB1+ZEA), or $50{\mu}g\;AFB1/kg$ $DM+100{\mu}g\;OTA/kg$ $DM+500{\mu}g\;ZEA/kg$ DM (AFB1+OTA+ZEA). Results: Dry matter intake and milk production were lower in goats fed AFB1+OTA+ZEA than in controls. Supplementation with AFB1, OTA, and ZEA significantly decreased red blood cell count, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, and mean platelet volume, and significantly increased white blood cell count, when compared with the control group. Compared with control, the combination of AFB1, OTA, and ZEA significantly increased alanine aminotransferase (ALT) and alkaline phosphatase (ALP) activities, total bilirubin (TBIL), interleukin-6, and malondialdehyde (MDA), but significantly reduced immunoglobulin A concentration, the activities of superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), and total antioxidant capacity (T-AOC) in serum. Administration of AFB1 combined with OTA led to higher ALP, ALT, TBIL, and MDA, as well as lower milk production, SOD and GSH-Px activities, and T-AOC, than administration of AFB1 combined with ZEA. Conclusion: The mixture of AFB1, OTA, and ZEA exerted the greatest adverse effects on dairy goats, meanwhile the deleterious damage of the other mycotoxin combinations were in varying degrees. The findings of this study could provide guidance for the prevention and treatment of the consequences of contamination of animal feeds with combinations of mycotoxin.