Occurrence of Fusarium Mycotoxin Fumonisin B1 and B2 in Animal Feeds in Korea

The objective of this study was to monitor the occurrence and levels of fumonisin B₁ (FB₁) and fumonisin B₂ (FB₂) in animal feeds distributed in South Korea in 2011. The contamination levels of FB₁ and FB₂ were investigated in 150 samples of compound feeds and in 40 samples of feed ingredients. The contamination rate of feed ingredients with FB₁ and FB₂ was 50 and 40 %, respectively. FB₂ was only found in samples contaminated with FB₁. Of the compound feeds, 85 % were contaminated by FB₁ and 47 % were contaminated by FB₂. The highest contamination rate of FBs was observed in compound feeds for cattle (FB₁: 100 %; FB₂: 80 %), followed by poultry feed (FB₁: 78 %; FB₂: 40 %) and swine feed (FB₁: 76 %; FB₂: 22 %). The highest contamination level (14,600 ng/g) for FB₁ were found in poultry broiler feed (early feeding period) samples, which had 82 % contamination rate (9/11), and the highest level of FB₂ (2,280 ng/g) was found in feed for fatting calves,which had a contamination rate of 100 %.     

Spargelstangenuntersuchungen zur Haupterntezeit auf Infektionen mitFusarium spp. und Kontaminationen mit Fumonisin B1

Asparagus spears collected from a total of six commercial plantings in Austria during the main harvest periods in May and June of 2003 and 2004 were examined for endophytic colonization byFusarium spp., particularlyF. proliferatum. Potentially toxigenic fungi such asF. proliferatum were isolated and identified by morphological characteristics using light microscopy. Fumonisin B₁ inF. proliferatum-infected asparagus spears was detected with IAS-HPLC-FLD or HPLC-MS/MS. The identity of endophytic fungi colonizing of a total of 816 individual spears was determined. The incidence of infection byF. proliferatum and otherFusarium spp. was highly dependent on location and sampling date. The dominantFusarium species among the endophytic microflora wasF. oxysporum. Other frequently isolated species includedF. proliferatum, F. sambucinum, F. culmorum, F. avenaceum andF. equiseti. The incidence ofF. proliferatum-infected asparagus spears was less than 10% at four of the six sampling locations. At the two remaining locations, 20–47% of the spears examined were infected withF. proliferatum. Further exploration of FB₁ generation in asparagus is required because the low levels of FB₁ (10–50 (μg/kg) detected in harvested spears in 2003 and 2004 cannot be explained by the results of this study.

     

Thermostability of Fumonisin B1, a Mycotoxin from Fusarium moniliforme, in Corn

Fumonisin B₁ (FB₁) is a mycotoxin from Fusarium moniliforme that is frequently associated with corn. Thermal treatments are used in many processes concerning this cereal and its derivatives. The thermostability of this toxin in dry contaminated corn, resulting from F. moniliforme culture, was studied in different time-temperature combinations. FB₁ was quantified by instrumentalized thin-layer chromatography after a two-step sequential development and postchromatographic derivatization by p-anisaldehyde. The identity of FB₁ in extracts, before and after heat treatments, was confirmed by high-pressure liquid chromatography. For each temperature, the natural logarithm of the ratio of resulting FB₁ on initial content (In C/C₀) is linearly correlated to exposure time. The calculated half-lives (L₅₀), corresponding to the 50% value, were 10 min, 38 min, 175 min, and 8 h at 150, 125, 100, and 75°C, respectively. There is a linear relationship between calculated L₅₀s on a logarithmic scale and temperature. Therefore FB₁ is not significantly destroyed by the main drying processes of corn or thermal treatments used for its derivatives. Other associated means are required for detoxification.     

Thermostability of Fumonisin B(1), a Mycotoxin from Fusarium moniliforme, in Corn

Fumonisin B(1) (FB(1)) is a mycotoxin from Fusarium moniliforme that is frequently associated with corn. Thermal treatments are used in many processes concerning this cereal and its derivatives. The thermostability of this toxin in dry contaminated corn, resulting from F. moniliforme culture, was studied in different time-temperature combinations. FB(1) was quantified by instrumentalized thin-layer chromatography after a two-step sequential development and postchromatographic derivatization by p-anisaldehyde. The identity of FB(1) in extracts, before and after heat treatments, was confirmed by high-pressure liquid chromatography. For each temperature, the natural logarithm of the ratio of resulting FB(1) on initial content (In C/C(0)) is linearly correlated to exposure time. The calculated half-lives (L(50)), corresponding to the 50% value, were 10 min, 38 min, 175 min, and 8 h at 150, 125, 100, and 75 degrees C, respectively. There is a linear relationship between calculated L(50)s on a logarithmic scale and temperature. Therefore FB(1) is not significantly destroyed by the main drying processes of corn or thermal treatments used for its derivatives. Other associated means are required for detoxification.     

Fumonisin B1 production by Fusarium species other than F. moniliforme in section Liseola and by some related species.

Strains of Fusarium proliferatum, F. subglutinans, F. anthophilum, F. annulatum, F. succisae, F. beomiforme, F. dlamini, F. napiforme, and F. nygamai from a variety of substrates and geographic areas were tested for the production of fumonisin B1 in culture. None of the cultures of F. subglutinans (0 of 23), F. annulatum (0 of 1), F. succisae (0 of 2), or F. beomiforme (0 of 15) produced fumonisin B1 in culture. Strains of F. proliferatum (19 of 31; 61%) produced fumonisin B1 in amounts ranging from 155 to 2,936 ppm, strains of F. anthophilum (3 of 17; 18%) produced fumonisin B1 in amounts ranging from 58 to 613 ppm, strains of F. dlamini (5 of 9; 56%) produced fumonisin B1 in amounts ranging from 42 to 82 ppm, strains of F. napiforme (5 of 33; 15%) produced fumonisin B1 in amounts ranging from 16 to 479 ppm, and strains of F. nygamai (10 of 27; 37%) produced fumonisin B1 in amounts ranging from 17 to 7,162 ppm. Of the species tested, F. proliferatum is the most important producer of fumonisin B1 because of its association with corn and animal mycotoxicoses such as porcine pulmonary edema. F. napiforme and F. nygamai also may be important because of their association with the food grains millet and sorghum. At present, F. anthophilum and F. dlamini are of minor importance because they are not associated with corn or other major food grains and have only a limited geographic range. This is the first report of the production of fumonisins by F. anthophilum, F. dlamini, and F. napiforme.     

芽孢杆菌B1、B2对豌豆尖镰孢菌抗菌机理的研究

同、异步培养结果表明：芽孢杆菌B1、B2对豌豆尖孢镰孢菌(Fusarium oxysporum Schl f．sp．pisi)有很强的抑菌作用。经B1、B2无菌液处理后的病原菌由灰白色变为白色,气生菌丝增多且纠结成团。抗菌显微特征是：导致病菌孢子和菌丝体膨大、畸形、原生质凝聚、孢子不萌发或萌发异常、菌丝生长点产生大量泡囊、生长受阻,后期菌丝体断裂、泡囊破裂、原生质外泄。B1、B2无菌液中蛋白含量分别为1795．53μg/mL和1345．93μg／mL,各含一种抗菌蛋白,其分子量分别为103．5kD(B1)和127．6kD(B2)。     

Incidence ofFusaria and occurrence of selected Fusarium mycotoxins on Lolium spp. in Germany

Test plantings with varieties ofLolium multiflorum andL perenne were harvested 4 to 7 times a year in 1991 and 1992. Samples were checked for the presence ofFusaria, the mycotoxins zearalenone, T-2 toxin, and diacetoxyscirpenol (DAS). Spectrum of species and the incidence ofFusaria and fusariotoxins are discussed in relation to the influencing factors site, variety ofLolium, harvesting time and year. Depending on these factors, 41 % to 100 % of the samples wereFusarium positive. Differences in infestation with Fusarium among varieties ofLolium perenne were dependent on location and did not correlate with yield. The six species ofFusarium pathogenic toLolium spp. (F. graminearum, F. culmorum, F. avenaceum, F. oxysporum, F. solani, and F. acuminatum) totaled 35.7 % of all the isolated strains. 14 species could be isolated fromLolium samples (descending frequency):F. culmorum, F. sambucinum, F. equiseti, F. acuminatum, F. semitectum, F. oxysporum, F. subglutinans, F. avenaceum, F. sporotrichioides, F. proliferatum, F. tricinctum, F. anthophilum, F. dimerum and F. graminearum. For the detection ofFusaria a promising new immunological method is presented. It is based on the genus specific production of exopolysaccharides byFusarium species. Mycotoxin contents in grass ranged from 0.01 to 4.75 ppm for zearalenone with 67 % positive samples and 0.3 % samples above 1 ppm, 0.04 to 2.78 ppm for T-2 toxin with 25 % positive samples and 2.8 % samples above 1 ppm, and 0.003 to 0.06 for DAS with 21.6 % positive samples. In silages, no T-2 toxin was detectable. IsolatedFusarium strains were checked for the ability to produce the mycotoxins zearalenone, T-2 toxin and DAS in culture. Most of the strains were positive for at least one of the toxins.     

Fumonisin B1 production by Fusarium species other than F. moniliforme in section Liseola and by some related species.

Strains of Fusarium proliferatum, F. subglutinans, F. anthophilum, F. annulatum, F. succisae, F. beomiforme, F. dlamini, F. napiforme, and F. nygamai from a variety of substrates and geographic areas were tested for the production of fumonisin B1 in culture. None of the cultures of F. subglutinans (0 of 23), F. annulatum (0 of 1), F. succisae (0 of 2), or F. beomiforme (0 of 15) produced fumonisin B1 in culture. Strains of F. proliferatum (19 of 31; 61%) produced fumonisin B1 in amounts ranging from 155 to 2,936 ppm, strains of F. anthophilum (3 of 17; 18%) produced fumonisin B1 in amounts ranging from 58 to 613 ppm, strains of F. dlamini (5 of 9; 56%) produced fumonisin B1 in amounts ranging from 42 to 82 ppm, strains of F. napiforme (5 of 33; 15%) produced fumonisin B1 in amounts ranging from 16 to 479 ppm, and strains of F. nygamai (10 of 27; 37%) produced fumonisin B1 in amounts ranging from 17 to 7,162 ppm. Of the species tested, F. proliferatum is the most important producer of fumonisin B1 because of its association with corn and animal mycotoxicoses such as porcine pulmonary edema. F. napiforme and F. nygamai also may be important because of their association with the food grains millet and sorghum. At present, F. anthophilum and F. dlamini are of minor importance because they are not associated with corn or other major food grains and have only a limited geographic range. This is the first report of the production of fumonisins by F. anthophilum, F. dlamini, and F. napiforme.     

Regulation of Fumonisin B1 Biosynthesis and Conidiation in Fusarium verticillioides by a Cyclin-Like (C-Type) Gene, FCC1

Fumonisins are a group of mycotoxins produced in corn kernels by the plant-pathogenic fungus Fusarium verticillioides. A mutant of the fungus, FT536, carrying a disrupted gene named FCC1 (for Fusarium cyclin C1) resulting in altered fumonisin B₁ biosynthesis was generated. FCC1 contains an open reading frame of 1,018 bp, with one intron, and encodes a putative 319-amino-acid polypeptide. This protein is similar to UME3 (also called SRB11 or SSN8), a cyclin C of Saccharomyces cerevisiae, and contains three conserved motifs: a cyclin box, a PEST-rich region, and a destruction box. Also similar to the case for C-type cyclins, FCC1 was constitutively expressed during growth. When strain FT536 was grown on corn kernels or on defined minimal medium at pH 6, conidiation was reduced and FUM5, the polyketide synthase gene involved in fumonisin B₁ biosynthesis, was not expressed. However, when the mutant was grown on a defined minimal medium at pH 3, conidiation was restored, and the blocks in expression of FUM5 and fumonisin B₁ production were suppressed. Our data suggest that FCC1 plays an important role in signal transduction regulating secondary metabolism (fumonisin biosynthesis) and fungal development (conidiation) in F. verticillioides.     

Fumonisin and T-2 toxin production of Fusarium spp. isolated from complete feed and individual agricultural commodities used in shrimp farming

Fusarium spp. are plant pathogens producing fumonisins and trichothecenes that both affect human and animal health. In the present study, 40 fungal strains were isolated and species identified from 35 shrimp feed samples and from 61 agricultural raw materials. F. verticillioides was the predominant species (85 %) mostly found in corn and soybean meal, while no Fusarium contamination was detected in shrimp feed. Levels of 10 % of F. oxysporum were isolated from peanut and 5 % of F. equiseti contamination in corn and peanut. To determine the ability of toxin production, enzyme-linked immunosorbent assay, polymerase chain reaction, and ultra-pressure liquid chromatography-tandem mass spectrometry were performed. All but four of the fumonisin-producing strains contained the FUM1 gene. No Fusarium synthesized T-2 toxin nor contained the Tri5 gene. This survey brings more data on mycotoxin contamination in the food chain of animal feed production, and leads to the awareness of the use of contaminated raw materials in shrimp farming.     

Incidence and Predictors of First Line Antiretroviral Regimen Modification in Western Kenya

Background

Limited antiretroviral treatment regimens in resource-limited settings require long-term sustainability of patients on the few available options. We evaluated the incidence and predictors of combined antiretroviral treatment (cART) modifications, in an outpatient cohort of 955 patients who initiated cART between January 2009 and January 2011 in western Kenya.

Methods

cART modification was defined as either first time single drug substitution or switch. Incidence rates were determined by Poisson regression and risk factor analysis assessed using multivariate Cox regression modeling.

Results

Over a median follow-up period of 10.7 months, 178 (18.7%) patients modified regimens (incidence rate (IR); 18.6 per 100 person years [95% CI: 16.2–21.8]). Toxicity was the most common cited reason (66.3%). In adjusted multivariate Cox piecewise regression model, WHO disease stage III/IV (aHR; 1.82, 95%CI: 1.25–2.66), stavudine (d4T) use (aHR; 2.21 95%CI: 1.49–3.30) and increase in age (aHR; 1.02, 95%CI: 1.0–1.04) were associated with increased risk of treatment modification within the first year post-cART. Zidovudine (AZT) and tenofovir (TDF) use had a reduced risk for modification (aHR; 0.60 95%CI: 0.38–0.96 and aHR; 0.51 95%CI: 0.29–0.91 respectively). Beyond one year of treatment, d4T use (aHR; 2.75, 95% CI: 1.25–6.05), baseline CD4 counts ≤350 cells/mm³ (aHR; 2.45, 95%CI: 1.14–5.26), increase in age (aHR; 1.05 95%CI: 1.02–1.07) and high baseline weight >60kg aHR; 2.69 95% CI: 1.58–4.59) were associated with risk of cART modification.

Conclusions

Early treatment initiation at higher CD4 counts and avoiding d4T use may reduce treatment modification and subsequently improve sustainability of patients on the available limited options.     

DNA Damage in Astrocytes Exposed to Fumonisin B1

Fumonisins are a group of toxic metabolites mainly produced by Fusarium moniliforme and Fusarium proliferatum, fungi that commonly occur on corn throughout the world. Fumonisin B₁ (FB₁), structurally resembling sphingoid bases, is an inhibitor of ceramide synthase, a key enzyme involved in de novo sphingolipid biosynthesis and in the reacylation of free sphingoid bases derived from sphingolipid turnover. This inhibitory effect leads to accumulation of free sphinganine (SA) and sphingosine (SO), inducing cell death. However, little is known on the down stream effectors activated by these sphingolipids in the cell death signaling pathway. We exposed rat astrocytes to FB₁ with the aim of evaluating the involvement of oxygen free radicals and of some other biochemical pathways such as caspase-3 activity and DNA damage. Our results indicate that FB₁ treatment (48, 72 h and 6 days in vitro, DIV, and 10, 50, 100 M) does not affect cell viability. Conversely, after 72 h of treatment, FB₁ (50 and 100 M) induced DNA damage and an enhancement of caspase-3 activity compared to controls. In addition, FB₁ increased the expression of HSP70 at 10 and 50 M at 48, 72 h, and 6 DIV of treatment. We conclude that DNA damage of apoptotic type in rat astrocytes is caused by FB₁ and that the genotoxic potential of FB₁ has probably been underestimated and should be reconsidered.     

Electrophoretic Karyotypes of Fusarium spp.

Migheli, Q., Berio, T., and Gullino, M. L. 1993. Electrophoretic karyotypes of Fusarium spp. Experimental Mycology 17, 329-337. The electrophoretic karyotype of 17 antagonistic and pathogenic strains of Fusarium spp. has been established by using contour-clamped homogeneous electric field gel electrophoresis. Intact chromosomal DNA was prepared from fungal protoplasts with standard procedures. Up to 11 distinct chromosomal bands were resolved after 184 h of migration at 50 V. Polymorphic karyotypes were observed in different species of Fusarium, formae speciales of F. oxysporum , and races of F. oxysporum f.sp. dianthi. Using the Schizosaccharomyces pombe and Saccharomyces cerevisiae chromosomes as size standards, the size of the Fusarium genome was estimated to range from approximately 18.1 to 51.5 Mb. The suitability of electrophoretic karyotyping as a tool for strain characterization, as well as some applications in hybridization analysis of Fusarium spp., is discussed.     

Incidence of Stenocarpella and Fusarium Cob Rots in Monoculture Maize under Different Tillage Systems

The incidence of maize cob rot caused by Stenocarpella maydis, S. macrospora, Fusarium moniliforme, F. subglutinans and F. graminearum was determined over two seasons under different tillage systems at various localities. Tillage had no effect on Fusarium spp. cob rots. S. macrospora occurred only at one locality, viz. Cedara, and no tillage effect was observed. Ploughing reduced the incidence of S. maydis cob rot at localities which had high incidences of disease. The relationship between severity of S. maydis cob rot and surface stubble mass was linear.     

Maize plants infestation by Fusarium spp. and deoxynivalenol in genetically modified corn hybrid and traditional maize cultivars

The objective of the performed investigations was to isolate pathogenic fungi from contaminated maize cobs, to assess the appearance of maize cob fusariosis and to determine grain contamination with deoxynivalenol in the cultivation of genetically modified maize containing a gene resistance against European corn borer (Ostrinia nubilalis Hbn) as well as selected non-modified cultivars. The plant material comprised the following genetically modified maize cultivar: DKC 3421 YG (MON 810) and non-modified cultivars obtained from Smolice Plant Breeding Ltd., IHAR Group: Junak (FAO 210-220), Prosna (FAO 220), SMH (FAO 230), Baca (FAO 220). Prior to harvesting, the occurrence of maize cob fusariosis was determined in the 89 (BBCH) developmental ripening stage. Microbiological assessment was carried out on grains selected from cobs characterized by various pathological symptoms. In 2008, a total of 133 isolates was obtained from the examined samples of infected maize plants, of which 51 isolates were species-identified, while in 2009, the total of 123 isolates were determined, of which 63 were species-identified. In both experimental years, the majority of isolates contained fungi from the Fusarium genus. The performed analysis of mean levels of cob contamination by fusarioses revealed that DKC 3421 YG (MON 810) and SMH (FAO 230) cultivars showed the smallest levels of contamination as well as the lowest percent of cob contamination per plant, while Junak (FAO 210-220) and Baca (FAO 220) cultivars were characterized by the highest degree of contamination. The lowest deoxynivalenol concentrations were determined in years 2008 and 2009 in the case of the DKC 3421 YG (MON 810) cultivar, whereas Prosna (FAO 220) cultivar was characterized by the highest deoxynivalenol concentration.     

Weed Dynamics during Transition to Conservation Agriculture in Western Kenya Maize Production

Weed competition is a significant problem in maize (Zea mays, L.) production in Sub-Saharan Africa. Better understanding of weed management and costs in maize intercropped with beans (Phaseolus vulgaris, L.) during transition to conservation agricultural systems is needed. Changes in weed population and maize growth were assessed for a period of three years at Bungoma where crops are grown twice per year and at Trans-Nzoia where crops are grown once per year. Treatments included three tillage practices: minimum (MT), no-till (NT) and conventional (CT) applied to three cropping systems: continuous maize/bean intercropping (TYPICAL), maize/bean intercropping with relayed mucuna after bean harvest (RELAY) and maize, bean and mucuna planted in a strip intercropping arrangement (STRIP). Herbicides were used in NT, shallow hand hoeing and herbicides were used in MT and deep hoeing with no herbicides were used in CT. Weed and maize performance in the maize phase of each cropping system were assessed at both locations and costs of weed control were estimated at Manor House only. Weed density of grass and forb species declined significantly under MT and NT at Manor House and of grass species only at Mabanga. The greatest declines of more than 50% were observed as early as within one year of the transition to MT and NT in STRIP and TYPICAL cropping systems at Manor House. Transitioning to conservation based systems resulted in a decline of four out of five most dominant weed species. At the same time, no negative impact of MT or NT on maize growth was observed. Corresponding costs of weed management were reduced by $148.40 ha^-1 in MT and $149.60 ha^-1 in NT compared with CT. In conclusion, farmers can benefit from effective and less expensive weed management alternatives early in the process of transitioning to reduced tillage operations.     

Fumonisin production and other traits of Fusarium moniliforme strains from maize in northeast Mexico.

Strains of Fusarium moniliforme from maize seed collected in four fields in northeast Mexico were tested for fumonisin production in culture, for sexual compatibility, and for vegetative compatibility by using non-nitrate-utilizing mutants. The test results indicate that a diverse population of fumonisin-producing strains of F. moniliforme (Gibberella fujikuroi) mating population A predominates and that a potential exists for production of fumonisins in Mexican maize.     

Transformation of progesterone by Fusarium spp.

Summary The microbiological transformation of progesterone to androsta-1,4-diene-3,17-dione was investigated. A comparison of various species ofFusaria under identical conditions showed a characteristic difference in the course of the transformation which allowed the division of the androstadienedione producingFusaria into two groups. Beside of the already knownFusaria several new androstadienedione producing ones were discovered.Presented in part at the 1st Yugoslav Microbiological Congress, Belgrade, September, 1968.     

Cellulolytic activity of four Fusarium spp.

Fusarium lini, F. lycopersici, F. pallidoroseum and F. semitectum grown in shake flasks produced, respectively, 0.19, 0.33, 0.13 and 0.09 units filter-paper cellulase/ml. Trichoderma reesei, in comparison, produced 0.8 U/ml.The authors are with Defence Food Research Laboratory, Mysore-570 011, India.     

临床常见镰刀菌的鉴别

目的从分子生物学角度寻找一种快速准确鉴定临床常见镰刀菌的方法。方法将受试镰刀菌接种于PDA培养基,观察其菌落及镜下形态,在此基础上PCR扩增受试镰刀菌的rDNA ITS并测其序列,在GenBank核酸序列数据库进行同源序列搜索及分析。选择限制性内切酶Dra Ⅱ和Cfr13 Ⅰ进行RFLP。设计了茄病镰刀菌的种特异性引物Sol1、Sol2,初步验证其特异性。结果形态学鉴定结果显示,茄病镰刀菌所占比例最高,除2株串珠镰刀菌外,其余镰刀菌ITS序列分析的结果与形态学鉴定结果一致。茄病、层生和串珠镰刀菌的Dra Ⅱ、Cfr13 I酶切带形互不相同。用Sol1、Sol2扩增受试菌的rDNA ITS,只有茄病镰刀菌为阳性。结论rDNA ITS序列测定及其PCR-RFLP可用于初步鉴别几种临床常见镰刀菌,合适的种特异性引物可以初步快速鉴定茄病镰刀菌。