Modulation of murine host response to enteric reovirus infection by the trichothecene deoxynivalenol.

Based on the known capacity of deoxynivalenol (DON) to target gut lymphoid tissue and IgA production, it was hypothesized that this mycotoxin interferes with the immune response to enteric reovirus infection. When mice were orally gavaged, first with 25 mg/kg bw DON, and then with reovirus serotype 1, strain Lang (T1/L) 2 or 12 h later, viral titers in the GI tract were 10-fold higher than control mice after 5 days. Virus was almost completely cleared in both treatment and control groups from intestinal tissue after 10 days. Real-time PCR indicated that, in infected control mice, reovirus lambda2 core spike (L2 gene) RNA per g feces in infected mice that were pretreated with DON was significantly higher at 1, 3, and 5 days than in infected mice only. In reovirus-infected mice, DON at doses of 10 and 25 mg/kg bw but not 2 and 5 mg/kg bw increased fecal L2 RNA, whereas DON doses as low as 2 mg/kg potentiated L2 RNA levels in Peyer's patches (PP). Reovirus-specific IgA levels in feces of mice treated with DON were significantly elevated, as were specific IgA responses in lamina propria and PP fragment cultures. Similar effects were observed for serum IgA and IgG. DON suppressed IFN-gamma responses in PP to reovirus at 3 and 5 days as compared to infected controls, while IL-2 mRNA concentrations were unaffected. Although reovirus alone did not induce Th2 cytokine mRNAs in PP, DON exposure significantly elevated IL-4, IL-6, and IL-10 mRNA expression at various times during the infection. ELISPOT revealed that mRNA expression data corresponded to suppression of IFN-gamma- and enhancement of IL-4-producing cell responses in PP cultures from DON-treated mice. Taken together, these data suggest that DON transiently increased both severity of the reovirus infection and shedding in feces as well as elevated reovirus IgA responses. These effects corresponded to suppressed Th1 and enhanced Th2 cytokine expression.     

单端孢菌素逆转肺癌耐药A549/DDP细胞耐药性及其机制研究

目的 探讨单端孢菌素对肺癌耐顺铂细胞系A549/DDP顺铂耐药性的逆转作用及机制。方法 应用MTS法检测单端孢菌素对A549/DDP细胞顺铂敏感性的影响,流式细胞术检测肿瘤细胞表面P-糖蛋白（P-Glycoprotein,P-pg）表达以及胞内罗丹明-123（Rhodamine-123,Rh-123）含量的变化,生化法检测细胞内SOD和GSH的水平,Western blot法和Real time PCR检测肿瘤细胞多药耐药蛋白MDR1、MRP1和Survivin表达的变化,Western blot法检测Akt磷酸化的变化,液相芯片法检测TGF-β,IL-6和IL-8的变化,应用双萤光报告基因技术检测细胞NF-κB和AP-1转录活性。结果 单端孢菌素可增加细胞对顺铂的敏感性,经5 μg·mL^-1和10 μg·mL^-1单端孢菌素作用72 h后,耐药逆转倍数（RF）为1.84和3.95倍。经5 μg·mL^-1和10 μg·mL^-1单端孢菌素作用24 h后,肿瘤细胞P-gp表达分别下降了62.6%和19.8%,细胞中Rh-123含量分别提高了183.3%和308.3%,细胞内SOD水平下降65.2%和50.1%,GSH水平下降 71.6%和46.3%,MDR1的mRNA水平下降了72.7%和52.3%,MRP1的mRNA水平下降了64.0%和22.5%,Survivin的mRNA水平下降了45.8%和14.7%,Akt磷酸化水平下降,TGF-β分泌水平下降了80.2%和51.5%,IL-6分泌水平下降了73.4%和37.2%,IL-8分泌水平下降了71.2%和43.2%,NF-κB转录活性下降42.3%和22.7%,AP-1的转录活性下降了57.4%和32.5%。结论 单端孢菌素逆转A549/DDP对顺铂的耐药性,这一作用与抑制药物外排,负调控肿瘤耐药相关蛋白的表达有关。     

Microanatomical changes in alveolar type II cells in juvenile mice intratracheally exposed to Stachybotrys chartarum spores and toxin.

Stachybotrys chartarum is an important environmental fungus. We have shown recently that alveolar type II cells are sensitive to exposure to Stachybotrys chartarum spores and to the trichothecene, isosatratoxin-F, both in vitro and in vivo, in a juvenile mouse model. This sensitivity is manifest as significant changes in the composition and normal metabolic processing of pulmonary surfactant. This study evaluated the effects of a single intratracheal exposure of S. chartarum spores and toxin on ultrastructure and dimensions of alveolar type II cells from juvenile mice. This was to determine whether there are concurrent morphological and dimensional changes in the alveolar type II cell that reflect the metabolic alterations in pulmonary surfactant that we observed in the treated mice. Marked ultrastructural changes were associated with alveolar type II cells in both S. chartarum and isosatratoxin-F treated animals compared to untreated, saline, and Cladosporium cladosporioides spore treated animals. These ultrastructural changes included condensed mitochondria with separated cristae, scattered chromatin and poorly defined nucleolus, cytoplasmic rarefaction, and distended lamellar bodies with irregularly arranged lamellae. Point count stereological analysis revealed a significant increase (p < 0.05) in lamellar body volume density in S. chartarum and isosatratoxin-treated animals after 48 h exposure. Mitochondria volume density was significantly lower in the isosatratoxin-F (48 h exposure) and S. chartarum treated (24 and 48 h exposure) animals compared to those in the other treatment groups. These results reveal that exposure to S. chartarum spores and toxin elicit cellular responses in vivo differently from those associated with exposure to spores of a nontoxigenic mold species. They also indicate that accumulation of newly secreted pulmonary surfactant in the alveolar space of S. chartarum and isosatratoxin-F treated animals might be a consequence of cellular trauma resulting in lamellar body volume density changes leading to increased release of pulmonary surfactant into the alveolar space.     

Mineral adsorbents for prevention of mycotoxins in animal feeds

Abstract

Mycotoxins are toxic metabolites produced by several fungi species, with the aflatoxins, fumonisins, zearalenone, trichothecenes and ochratoxin A being the most important found in feedstuffs. The economic impact caused by mycotoxins motivated the investigation of detoxification strategies to reduce its bioavailability by enterosorption. Although there are several types of adsorbents, the efficiency of the adsorption depends on the physical and chemical characteristics of both the adsorbent and the mycotoxin. This review describes the most important types of mineral adsorbents [aluminosilicates, HSCAS, bentonites (montmorillonites), zeolites, sepiolite, diatomite and activated carbons] used in feeds, especially for poultry and pigs, and their adsorption mechanisms.     

Contamination,Detection and Control of Mycotoxins in Fruits and Vegetables

Mycotoxins are secondary metabolites produced by pathogenic fungi that colonize fruits and vegetables either during harvesting or during storage. Mycotoxin contamination in fruits and vegetables has been a major problem worldwide, which poses a serious threat to human and animal health through the food chain. This review systematically describes the major mycotoxigenic fungi and the produced mycotoxins in fruits and vegetables, analyzes recent mycotoxin detection technologies including chromatography coupled with detector (i.e., mass, ultraviolet, fluorescence, etc.) technology, electrochemical biosensors technology and immunological techniques, as well as summarizes the degradation and detoxification technologies of mycotoxins in fruits and vegetables, including physical, chemical and biological methods. The future prospect is also proposed to provide an overview and suggestions for future mycotoxin research directions.     

Acute inflammatory responses to Stachybotrys chartarum in the lungs of infant rats: time course and possible mechanisms.

Stachybotrys chartarum has been linked to building-related respiratory problems including pulmonary hemorrhage in infants. The macrocyclic trichothecenes produced by S. chartarum have been the primary focus of many investigations. However, in addition to trichothecenes this fungus is capable of producing other secondary metabolites and a number of protein factors. This study examines the effects of intact, autoclaved, and ethanol-extracted spores on the lungs of infant rats as an approach to differentiate between secondary metabolites and protein factors. Seven-day-old infant rats were exposed intratracheally to 1 x 10(5) spores/g body weight (toxic strain JS58-17) and sacrificed at various times up to 72 h. The inflammatory response was measured by morphometric analysis of the lungs and determination of inflammatory cells and cytokine concentrations in bronchoalveolar lavage (BAL) fluid. Alveolar space was greatly reduced in animals exposed to fungal spores compared to phosphate buffered saline (PBS)-treated controls. The largest effects were observed in pups treated with intact spores where alveolar space 24 h after treatment was 42.1% compared to 56.8% for autoclaved spores, 51.1% for ethanol-extracted spores, and 60.6% for PBS-treated controls. The effects of different spore preparations on inflammatory cells, cytokine, and protein concentrations in the BAL fluid can be ranked as intact > autoclaved > extracted. Tumor necrosis factor alfa (TNF-alpha), interleukin 1-beta (IL-1beta), and neutrophils were the most sensitive indicators of inflammation. The difference between autoclaved (100% trichothecene toxicity, denatured/enzymatically inactive proteins) and intact (100% trichothecene activity, unaltered/released proteins) spores indicates the involvement of fungal proteins in the inflammatory response to S. chartarum and sheds new light on the clinical importance of "nontoxic" strains.     

Ecophysiology of Fusarium chaquense a Novel Type A Trichothecene Producer Species Isolated from Natural Grasses

Fusarium chaquense, a recently formally described novel species, has been identified as an T-2 toxin (T-2), HT-2 toxin (HT-2) and other toxins producer in natural grasses (Poaceae) from Argentina. The major objective of this study was to describe the effect of water activity (a_W, 0.995, 0.98, 0.95, 0.93 and 0.91), temperature (15, 25 and 30 °C) and incubation time (5, 15 and 25 days) on growth and to evaluate the production of T-2, HT-2 toxins and beauvericin (BEA) by two F. chaquense strains in a grass-based media. The results showed a wide range of conditions for F. chaquense growth and mycotoxin production. Both strains had a maximum growth rate at the highest a_W (0.995) and 25 °C. Regarding mycotoxin production, more T-2 than the other analysed mycotoxins were produced by the two strains. T-2 production was favoured at 0.995 a_W and 30 °C, while HT-2 production at 0.98–0.95 a_W and 15 °C. The maximum levels of BEA were produced at 0.995 a_W and 25–30 °C. Two-dimensional profiles of a_W by temperature interactions were obtained from these data in order to identify areas where conditions indicate a significant risk of mycotoxins accumulation on grass. For its versatility on growth and mycotoxin production in a wide range of a_W and temperatures, F. chaquense would have an adaptive advantage over other Fusarium species, and this would explain its high frequency of isolation in natural grasses grown up in the Chaco wetlands.     

Searching for the Fusarium spp. Which Are Responsible for Trichothecene Contamination in Oats Using Metataxonomy to Compare the Distribution of Toxigenic Species in Fields from Spain and the UK

The contamination of oats with Fusarium toxins poses a high risk for food safety. Among them, trichothecenes are the most frequently reported in European oats, especially in northern countries. The environmental conditions related to the climate change scenario might favour a distribution shift in Fusarium species and the presence of these toxins in Southern European countries. In this paper, we present an ambitious work to determine the species responsible for trichothecene contamination in Spanish oats and to compare the results in the United Kingdom (UK) using a metataxonomic approach applied to both oat grains and soil samples collected from both countries. Regarding T-2 and HT-2 toxin producers, F. langsethiae was detected in 38% and 25% of the oat samples from the UK and Spain, respectively, and to the best of our knowledge, this is the first report of the detection of this fungus in oats from Spain. The relevant type B trichothecene producer, F. poae, was the most frequently detected Fusarium species in oats from both origins. Other important trichothecene producers, such as the Fusarium tricinctum species complex or Fusarium cerealis, were also frequently detected in oat fields. Many Fusarium toxins, including T-2 and HT-2 toxins, deoxynivalenol, or nivalenol, were detected in oat samples. The results obtained in this work revealed a clear change in the distribution of trichothecene producers and the necessity to establish the potential of these species to colonize oats and their ability to produce mycotoxins.     

Mycotoxin Co-Occurrence in Milks and Exposure Estimation: A Pilot Study in São Paulo,Brazil

The aim of this study was to conduct a first evaluation on the co-occurrence of aflatoxins (AF) M₁, B₁, B₂, G₁ and G₂; fumonisins (F) B₁ and B₂; deoxynivalenol (DON); de-epoxydeoxinivalenol (DOM-1); ochratoxin A (OTA); zearalenone (ZEN); α-zearalenol (α-ZEL); and β-zearalenol (β-ZEL) in 68 samples of fluid milk consumed in Pirassununga, São Paulo, Brazil. The probable daily intake (PDI) was also calculated for each mycotoxin evaluated. Mycotoxins were determined by liquid chromatography coupled to mass spectrometry. Sixty-two (91.2%) samples contained at least one type of mycotoxin. AFM₁ was found in 6 samples (8.8%), and none of them presented concentrations above the Brazilian maximum permitted level in milk (500 ng/L). Low levels of non-regulated mycotoxins DOM-1, OTA, FB₁, FB₂, α-ZEL and β-ZEL were found in 6 (8.8%), 17 (25%), 10 (14.7%), 3 (4.4%), 39 (57.4%) and 28 (41.2%) samples of milk, respectively. None of the PDIs calculated for the quantified mycotoxins were above recommended values, indicating low exposure through milk consumption in the area studied. However, 21 samples (30.9%) contained 2–4 types of mycotoxins, which warrants concern about the potential adverse effects of mycotoxin mixtures in milks.     

Accumulation Kinetics of Three Scirpentriol-Based Toxins in Oats Inoculated in Vitro with Isolates of Fusarium sporotrichioides and Fusarium poae

Autoclaved oats were inoculated with a strain of Fusarium sporotrichioides or Fusarium poae. Moisture content of oats after inoculation was at 38%, incubation took place in standing culture at 28 °C. The A-type trichothecenes, 4,15-diacetoxyscirpenol (4,15-DAS), 15-monoacetoxyscirpenol (15-MAS), and scirpentriol (SCIRP) were analyzed by GC/MS. For each strain, three culture flasks were harvested at 2-3 day intervals starting immediately after inoculation. Total incubation time was 42 days (F. poae) and 56 days (F. sporotrichioides). Following peak accumulation, 4,15-DAS decreased below the detection limit for both strains, 15-MAS decreased below this limit for the isolate of F. sporotrichioides, for the isolate of F. poae it decreased to a level markedly below the peak value. SCIRP, after having peaked, decreased to some extent for the strain F. sporotrichioides, with a significant (P = 0.0029) negative linear regression of toxin content against culture age during this period. The content of 15-MAS, and in part also of 4,15-DAS, decreased along with an increase of SCIRP. This sequential accumulation pattern suggests the successive induction of esterases deacetylating 4,15-DAS and 15-MAS, as well as of enzymes involved in the metabolization of the parent alcohol, SCIRP. The results may explain, at least in part, the somewhat higher incidence in naturally contaminated compounds reported in the literature for SCIRP compared to 4,15-DAS and 15-MAS.