Microbial metabolites have been identified as a promising class of natural herbicides due to their effective control against weeds and a relatively low environmental impact. Here we report on the potency and crop safety of a natural compound with herbicidal properties, the metabolite SPRI-70014 from Streptomyces griseolus CGMCC 1370. The compound showed excellent herbicidal activities on various broadleaf and gramineous weeds in both greenhouse and field trials. In germination inhibition experiments, SPRI-70014 inhibited the emergence of both root and shoot at 1 mg L−1. At a dose of 31.3 g ai ha−1, SPRI-70014 provided effective control over most broadleaf weeds in greenhouse trials. Observations on absorption and translocation using a cucumber plant model system indicated that SPRI-70014 could be absorbed by the root but only partly by the stem. Field trials showed that SPRI-70014 provided effective control over most weed species tested at a dose of 1,000 g ai ha−1. Crop safety experiments showed that the compound had no harmful effect on peanut or wheat plants at doses up to 2,000 g ai ha−1. These results indicated that this compound could be developed as a potential POST herbicide for control of broadleaf weeds in peanut and wheat fields.

Conidia of Myrothecium verrucaria, sprayed in an aqueous phase–paraffinic crop oil emulsion (1:1 v/v) at 470 L/ha, controlled red, ivyleaf, smallflower, and tall morningglory plants (three- to five-leaf stage) by causing severe necrotic injury to leaves and stems. Conidia were not efficacious if applied in an aqueous carrier without oil. When applied in the field as directed postemergence treatments to sugarcane, a concentration of 4 × 108 conidia/ml generally provided > 90% death of morningglory, comparable with the atrazine standard at 2.2 kg ai/ha, and did not cause significant crop injury. Conidia produced on potato dextrose agar or rice flour slurry were about equally effective. When killed by autoclaving, conidia continued to be efficacious, indicating that the symptoms produced by the fungus were not primarily caused by infection. A high performance liquid chromatography analysis of filtrates from the fungal growth media or of harvested conidia showed the presence of several macrocyclic trichothecenes (MT), some known to be phytotoxins. These included verrucarin A and H, roridin A and H, and isororidin E for filtrates and verrucarin A and roridin A for conidia. However, only trace amounts of MT were detected in leaves of treated morningglory plants at 24 h after treatment and none at 48 and 96 h even though the fungus was isolated from leaves up to 14 d after treatment. Further study is needed to identify the causal agents responsible for the phytotoxicity produced by M. verrucaria and to assess potential of this organism as a mycoherbicide.

There is increased interest towards the application of carbon based nanomaterials to biosensors since these can be used to quickly detect presence of the toxins in food, agricultural and environmental systems. The accurate, faster and early detection of food toxins is presently very important for ensuring safety and shelf life of agricultural commodities resulting from food contamination. The carbon materials (CNTs) and recently discovered graphene have been predicted to be promising candidates in the development of electrochemical biosensor owing to their exceptionally large surface area and interesting electrochemical properties. We focus on some of the recent results obtained in our laboratories pertaining to the development of biosensors based on multi-walled carbon nanotubes and graphene for mycotoxin(aflatoxin ) detection.

The safety of the food supply is a subject of intense interest to consumers, particularly as a result of large-scale outbreaks that involve hundreds and sometimes thousands of consumers. During the last decade, this concern about food safety has expanded to include the diets of companion animals as a result of several incidences of chemical toxicities and infectious disease transmission. This has led to increased research into the causes and controls for these hazards for both companion animals and their owners. The following summary provides an introduction to the issues, challenges and new tools being developed to ensure that commercial pet foods are both nutritious and safe.

Deoxynivalenol (DON) and fumonisins (FB) are mycotoxins produced by Fusarium species, which naturally co-occur in animal diets. The gastrointestinal tract represents the first barrier met by exogenous food/feed compounds. The purpose of the present study was to investigate the effects of DON and FB, alone and in combination, on some intestinal parameters, including morphology, histology, expression of cytokines and junction proteins. A total of twenty-four 5-week-old piglets were randomly assigned to four different groups, receiving separate diets for 5 weeks: a control diet; a diet contaminated with either DON (3 mg/kg) or FB (6 mg/kg); or both toxins. Chronic ingestion of these contaminated diets induced morphological and histological changes, as shown by the atrophy and fusion of villi, the decreased villi height and cell proliferation in the jejunum, and by the reduced number of goblet cells and lymphocytes. At the end of the experiment, the expression levels of several cytokines were measured by RT-PCR and some of them (TNF-α, IL-1β, IFN-γ, IL-6 and IL-10) were significantly up-regulated in the ileum or the jejunum. In addition, the ingestion of contaminated diets reduced the expression of the adherent junction protein E-cadherin and the tight junction protein occludin in the intestine. When animals were fed with a co-contaminated diet (DON+FB), several types of interactions were observed depending on the parameters and segments assessed: synergistic (immune cells); additive (cytokines and junction protein expression); less than additive (histological lesions and cytokine expression); antagonistic (immune cells and cytokine expression). Taken together, the present data provide strong evidence that chronic ingestion of low doses of mycotoxins alters the intestine, and thus may predispose animals to infections by enteric pathogens.

Deoxynivalenol (DON) is a toxic fungal metabolite found on wheat, maize and barley. We previously reported a significant association between the amount of DON in a single 24 h urine sample and the average cereal intake over 7 d for 300 UK adults. In this more detailed analysis of the data, food diary information (n 255) for the day of urine collection (model I), the previous 24 h period (model II) and the day of urine collection plus the previous 24 h combined (model III) were further examined to assess whether the recent intake of cereal correlated more strongly with urinary DON, compared with the longer-term assessment of usual cereal intake from 7 d food diaries (model IV). DON was detected in 254/255 (99·6 %) urine samples (mean 12·0 μg/d; range not detected–66 μg/d). For all the models, total cereal intake was positively associated with urinary DON (P < 0·001) in each model. The goodness of fit (adjusted R2 value) was used to assess how well each model explained the variation in urinary DON. Model I provided a better goodness of fit (adjusted R2 0·22) than model IV (adjusted R2 0·19), whereas model III provided the best fit (adjusted R2 0·27). These data suggest that the inter-individual variation in urinary DON was somewhat better explained by recent cereal intake compared with usual cereal intake assessed over 7 d.

Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium verticillioides, a fungus that commonly contaminates maize. Sex-related effects of FB1 have been observed with respect to carcinogenicity in rodents, to performances in pigs and immunosuppression in mice. In the present study the sex-related effect of FB1 on the pig immune response was determined. Female and castrated male piglets received for 28d either control feed or feed contaminated with 8mg FB1/kgfeed in the form of F. verticillioidesculture material. At day 7 and day 21, animals were immunised subcutaneously with a Mycoplasma agalactiae vaccine. Ingestion of FB1-contaminated feed significantly decreased weight gain in males but had no effect in females. No sex-related difference was observed in biochemical parameters, but a higher level of creatinine was noted in toxin-treated animals. FB1 also altered the pig immune response in a sex-specific manner. In males, ingestion of FB1-contaminated feed significantly decreased specific antibody levels after vaccination as well as the mRNA expression level of IL-10. In females, the toxin has no effect on specific antibodies or on cytokine mRNA levels. The results of the present study indicatethat FB1 is immunosuppressive in pigs. The magnitude of this FB1-induced immunosuppression is highly dependent on sex, with males being more susceptible than females.

Recent findings have suggested that oxidative damage might contribute to the cytotoxicity and carcinogenicity of aflatoxin B1 (AFB1). Induction of oxidative stress also plays an important role in the toxicity of another mycotoxin, ochratoxin A (OTA). In the present study, the protective effect of cyanidin-3-O-β-glucopyranoside (C-3-G; an anthocyanin contained in oranges, blackberries, strawberries and cranberries) against AFB1- and OTA-induced cytotoxicity was investigated in a human hepatoma-derived cell line (Hep G2) and a human colonic adenocarcinoma cell line (CaCo-2). The ability of C-3-G to reduce the production of reactive oxygen species (ROS), the inhibition of protein and DNA synthesis and the apoptosis caused by the two mycotoxins was also investigated in both cell lines. Our experiments proved the significant cytoprotective effect of C-3-G in vitro against OTA- and AFB1-induced cell damage. In particular, 24 h of pretreatment with 50 μm-C-3-G inhibited the cytotoxicity of 10 μm-AFB1 (by 35 %) and of 10 μm-OTA (by 25 %) in Hep G2 cells (P<0·001) and of 10 μm-AFB1 (by 10 %, P<0·01) and of 10 μm-OTA (by 14 %, P<0·05) in CaCo-2 cells. Moreover, 50 μm-C-3-G attenuated ROS production induced by the two toxins in both cell lines (P<0·05). Inhibition of DNA and protein synthesis induced by the mycotoxins was counteracted by pretreatment with the antioxidant at 50 μm. Similarly, apoptotic cell death was prevented as demonstrated by a reduction of DNA fragmentation and inhibition of caspase-3 activation. The in vitro free-radical scavenging capacity of the anthocyanin was tested with the Briggs–Rauscher oscillating reaction. This system works at pH approximately 2. The results showed good scavenging power, in accordance with the observed inhibition of ROS production.

Since the recognition of mycotoxicosis about 30 years ago, various research projects have been undertaken to develop measures to prevent or reduce the serious financial losses it causes. Although inhibitors which prevent mould growth and the production of toxic substances have been developed, several factors still limit their effectiveness and practical use by the feed industry. Various kinds of sorbent materials have also been assessed for their ability to remove or diminish the adverse effects of mycotoxins in animal feeds. Even though it does not bind all the mycotoxin and allows partial absorption of toxin in the gastrointestinal tract, hydrated sodium calcium aluminosilicate (HSCAS) is considered to be an outstandingly effective additive. Several new possibilities have emerged involving the use of the sulphur-containing amino acids, antioxidants, vitamins, trace mineral and other nutrients in building detoxicants. Research into methods of preventing mycotoxicosis in poultry needs to be carried out against the background of the underlying levels of mycotoxins found under the normal storage conditions for feed used in the industry.

The presence of harmful substances such as organochlorine pesticides, heavy metals, radionuclides and mycotoxins in poultry feed is sometimes unavoidable. The reduction of absorption of fat-soluble organochlorine pesticides (e.g. DDT or dieldrin) and enhancement of elimination from the body is not easy to accomplish. The level of more volatile compounds (e.g. lindane) can be reduced by freeze drying of the product. Removal of the fat from the product will also decrease the level of these lipophilic compounds. The absorption of (heavy) metals from the intestine shows many interactions which sometimes may be used in practical situations to reduce intestinal absorption, toxicity and residue formation of a particular heavy metal. Reduction of levels in contaminated products has not been described. Adsorbents such as bentonite or zeolite reduce, to some extent, the absorption of radionuclides in poultry. Mycotoxin formation in feedstuffs should and can, sometimes, be prevented. Ammoniation of feedstuffs is a good method of reducing aflatoxin levels. Adsorbents such as hydrated sodium calcium aluminosilicate may also help to alleviate mycotoxin problems arising from the feed.

The avian kidney has shown a remarkable ability to maintain adequate and even normal function in the face of a mycotoxin challenge. Full evaluation of the nephrotoxicity of a substance must therefore go beyond pathological and ultrastructural documentation and include a complete functional evaluation. To date, only three nephrogenic mycotoxins, citrinin, ochratoxin A, and aflatoxin B1 have been assessed for their ability to alter avian renal function. At non-lethal doses, citrinin appears to have acute reversible effects on the distal portion of the nephron, possibly acting to inhibit water absorption. Ochratoxin A is more potent and less acute than citrinin but less site-specific in that both proximal and distal tubules are damaged, resulting in severe loss of both fluids and electrolytes. Aflatoxin B1 at a dosage and duration which induced hepatotoxicity, concurrently exerted nephrogenic effects such as increased urinary calcium excretion and decreased inorganic phosphate excretion. In commercial broilers aflatoxin B1 has been shown to decrease plasma levels of 25-hydroxy vitamin D, 1,25-dihydroxy vitamin D and may also decrease endogenous parathyroid hormone synthesis and the renal sensitivity to parathyroid hormone. Furthermore, exposure to aflatoxin B1 may cause prolonged alteration in renal function such as reduced glomerular filtration rate. This review summarizes the studies which have been conducted to evaluate avian renal function during both acute and chronic exposure to these three mycotoxins.

Biological control efforts on Parthenium hysterophorus L. (Asteraceae) in India have gained momentum after the limitations of other methods were realized. Native surveys revealed a large number of insects, but none of them was host specific. Although the introduced beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) has established at the sites of initial releases, its real impact on the weed and performance in different parts of the country need further evaluation. Fungal pathogens of the weed hold promise for classical as well as microherbicidal control. The use of parthenium phyllody MLO as a biocontrol agent requires establishment of host and vector specificity. Mycotoxins are a potential group of herbicides on which serious studies are yet to begin. Studies on control of the weed through interference and allelopathy by Cassia uniflora Mill. (= C. sericea Sw.) (Leguminosae) have produced promising results. Toxic leachates of C. uniflora and autotoxic principles of the weed deserve attention. Integrated biocontrol strategies envisaged for wastelands using introduced insects and pathogens, allelopathic plants, and agroecosystems using native pathogens, mycotoxins and autotoxic principles, will help combat this apparently invincible weed.