Production of trichothecene and non-trichothecene mycotoxins by Fusarium species isolated from maize in Minnesota

Eighty-two cultures of Fusarium species isolated in 1986 from moldy maize in Minnesota were each cultured on rice for 4 weeks and found to produce the following mycotoxins: F. graminearum isolates, deoxynivalenol (DON, 4–225 g/g), 3-acetyldeoxynivalenol (3-ADON, 2–4g/g), 15-acetyldeoxynivalenol (15-ADON, 1–35 g/g) and zearalenone (ZEA, 5–4350 g/g); F. moniliforme, fusarin C (detectable amounts to 1000 g/g); F. mòniliforme, F. oxysporum, F. proliferatum and F. subglutinans isolates, moniliformin (15–6775 g/g); F. moniliforme, F. proliferatum, and F. subglutinans isolates, fusaric acid (detectable amounts). Other mycotoxins screened for in each rice sample and not detected were T-2 toxin, HT-2 toxin, neosolaniol, T-2 tetraol, nivalenol, fusarenon-X, scirpenols, alpha and beta trans-zearalenols, wortmannin, and fusarochromanone. The rat feeding bioassay indicated that other, unidentified toxins may be present.     

Dislocated type-A spermatogonia in human seminiferous tubules

Summary Type-A spermatogonia can be found in different locations throughout the germinal epithelium of human seminiferous tubules. Generally they represent the population of germ cells adjacent to the basal lamina, but under special conditions they may be located in the adluminal compartment. This aberrant location is found not only in the terminal segments but also in the seminiferous tubules of men older than 65 years of age, and in cases of intratubular seminoma. Furthermore, in both cases, type-A spermatogonia may occupy an intermediate position between basal and intraluminal locations, without showing any signs of cytological damage.Supported by grants from the Deutsche Forschungsgemeinschaft (Ho 388/5-3) and the Alexander von Humboldt-Stiftung     

Interacting climate change environmental factors effects on Fusarium langsethiae growth,expression of Tri genes and T-2/HT-2 mycotoxin production on oat-based media and in stored oats

This study examined the effect of climate change (CC) abiotic factors of temperature (20, 25, 30 °C), water activity (a_w; 0.995, 0.98) and CO₂ exposure (400, 1000 ppm) may have on (a) growth, (b) gene expression of biosynthetic toxin genes (Tri5, Tri6, Tri16), and (c) T-2/HT-2 toxins and associated metabolites by Fusarium langsethiae on oat-based media and in stored oats. Lag phases and growth were optimum at 25 °C with freely available water. This was significantly reduced at 30 °C, at 0.98 a_w and 1000 ppm CO₂ exposure. In oat-based media and stored oats, Tri5 gene expression was reduced in all conditions except 30 °C, 0.98 a_w, elevated CO₂ where there was a significant (5.3-fold) increase. The Tri6 and Tri16 genes were upregulated, especially in elevated CO₂ conditions. Toxin production was higher at 25 °C than 30 °C. In stored oats, at 0.98 a_w, elevated CO₂ led to a significant increase (73-fold) increase in T2/HT-2 toxin, especially at 30 °C. Nine T-2 and HT-2 related metabolites were detected, including a new dehydro T-2 toxin (which correlated with T-2 production) and the conjugate, HT-2 toxin, glucuronide. This shows that CC factors may have a significant impact on growth and mycotoxin production by F. langsethiae.     

Exogenous H(2)O(2) and catalase treatments interfere with Tri genes expression in liquid cultures of Fusarium graminearum

Effect of exogenous H(2)O(2) and catalase was tested in liquid cultures of the deoxynivalenol and 15-acetyldeoxynivalenol-producing fungus Fusarium graminearum. Accordingly to previous results, H(2)O(2) supplementation of the culture medium leads to increased toxin production. This study indicates that this event seems to be linked to a general up regulation of genes involved in the deoxynivalenol and 15-acetyldeoxynivalenol biosynthesis pathway, commonly named Tri genes. In catalase-treated cultures, toxin accumulation is reduced, and Tri genes expression is significantly down regulated. Furthermore, kinetics of expression of several Tri genes is proposed in relation to toxin accumulation. Biological meanings of these findings are discussed.     

Effects of four trichothecene mycotoxins on activation marker expression and cell proliferation of human lymphocytes in culture

Four trichothecene mycotoxins – the type A trichothecenes T2-toxin and diacetoxyscirpenol and the type B trichothecenes nivalenol and deoxynivalenol – were studied. The effects of these mycotoxins on the expression of the sequentially expressed activation markers CD69, CD25, and CD71 and on proliferation of human lymphocytes were studied in culture with a duration of up to 72 h.All the examined toxins affected activation marker expression in a similar way. After 6 h, the CD69 expression was lower in exposed cultures compared to controls. After 24 and 48 h of exposure, an increased frequency of cells expressing CD69 was found in exposed cultures, indicating a delay in downregulation of CD69 expression. Stimulation of CD25 expression was observed for doses below the IC₅₀ value, while suppression was found for higher doses. The pattern was different from that detected for CD69 expression, in that an increased expression of CD25 never occurred after exposure to the highest concentration of the toxin, and in that no stimulatory effects were found after 48 h of exposure, indicating that the response was inhibited and not delayed. The effects of toxin exposure on CD71 expression were in many respects similar to the effects on CD25 expression.We conclude that the trichothecene mycotoxins investigated in this study inhibited the cell cycle in a similar way and exert their main antiproliferative action rather early in the cell cycle, before or in conjunction with CD25 expression.     

初中学生人格类型对心理旋转能力性别差异的影响

目的:考察初中学生心理旋转能力性别差异、典型A型和B型人格被试心理旋转能力状况,及人格类型与心理旋转能力性别差异的关系。方法:采用标准心理旋转能力测验和A型人格问卷调查了260名初中一年级至三年级被试,并对人格类型对心理旋转性别差异的影响进行方差分析。结果:心理旋转能力性别差异具有跨年级(初一至初三)的一致性(初一:男4.618±0.504,女3.400±0.536;初二:男7.389±0.400,女5.30±0.416;初三:男6.207±0.546,女4.286±0.534;F=12.586,P=0.000);(2)A型人格被试心理旋转能力高于B型人格被试(6.09±0.42/4.71±0.425;F=5.320,P=0.023);(3)A型人格被试性别差异显著(男7.259±0.583,女4.920±0.606;F=7.77,P=0.006),而B型人格被试性别差异不显著(男5.269±0.553,女4.255±0.646;F=2.26;P=0.136),人格类型是影响心理旋转能力性别差异因素之一。结论:尽管心理旋转能力存在显著的性别差异,但这种差异受众多因素影响。     

Genetic and mutational tools for investigating the genetics and molecular biology of trichothecene production inGibberella pulicaris (Fusarium sambucinum)

Gibberella pulicaris (Fusarium sambucinum) is a promising organism for studying the genetics and regulation of trichothecene biosynthesis; conditions for obtaining fertile crosses have been defined (Desjardins & Beremand, 1987) and crosses between natural variants have provided some information about the number, location, arrangement, and role of genes which determine trichothecene production (Desjardins & Beremand, 1987; Beremand & Desjardins, 1988). The development of some additional experimental tools and methodologies required for the further genetic analysis of trichothecene production inG. pulicaris are described in the present study. A highly fertile, isogenic line was constructed forG. pulicaris strain R-6380. The ability to readily generate mutants in this strain was also demonstrated. Both biochemical and morphological mutants were obtained following UV-mutagenesis. The inheritance of some of these mutations through meiosis indicated that they will be useful genetic markers for crosses and mapping studies. Since strain R-6380 is also transformable (Salch & Beremand, 1988), it is an excellent choice for transmission and molecular genetic studies involving trichothecene production.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Auswahl von GC-Phasen und Optimierung von Trichothecen-Trennungen mittels Computersimulation

Gas chromatography combines high resolution with good sensitivity (ECD) for the simultaneous analysis of trichothecenes. With the aid of computer-supported GC simulation based on thermodynamic retention indices, optimized GC methods for 4 different phase polarities have been developed. The verification with polar and unpolar columns in 2 GCs under optimized separation conditions provides highly reliable results.

Presented at the 26^th Mykotoxin-Workshop in Herrsching, Germany, May 17–19, 2004