Two new toxic yellow Inocybe species from China: morphological characteristics, phylogenetic analyses and toxin detection

Some species of Inocybes. str. caused neurotoxic poisoning after consumption around the world. However, there are a large number of species in this genus that have not been studied for their toxicity or toxin content. In this study, we report two new toxic yellow Inocybes. str. species from China based on morphological characteristics, phylogenetic analyses and toxin detection. Among the two species, Inocybe squarrosolutea is reported as a newly recorded species of China. We also describe a new species, I. squarrosofulva, which is morphologically similar to I. squarrosolutea. The new species is characterized by its ochraceous squarrose pileus, distinctly annulate cortina on the stipe, nodulose basidiospores and thick-walled pleurocystidia. Muscarine in the fruitbodies was detected by UPLC–MS/MS, the content in I. squarrosolutea and I. squarrosofulva were 136.4 ± 25.4 to 1683.0 ± 313 mg/kg dry weight and 31.2 ± 5.8 to 101.8 ± 18.9 mg/kg dry weight, respectively.

Application of hyperspectral imaging to detect toxigenic Fusarium infection on cornmeal

One of the most important food safety issues is the detection of mycotoxins, the ubiquitous, natural contaminants in cereals. Hyperspectral imaging (HSI) is a new method in food science, it can be used to predict non-destructively the changes in composition and distribution of compounds. That is why, in the last decade, the potential of HSI has been evaluated in many fields of food science, including mycotoxin research.The aim of the recent study was to test the feasibility of HSI for the differentiation according to the toxin content of cornmeal samples inoculated with Fusarium graminearum, Fusarium verticillioides and Fusarium culmorum and samples with natural levels of mycotoxins. Samples were measured in the near infrared wavelength range of 900–1,700 nm and mean spectra of selected regions of interest of each image were pre-treated using Savitzky-Golay smoothing and standard normal variate (SNV) method. On the spectra, partial least squares discriminant analysis (PLS-DA) was carried out according to the level of contamination. Partial least squares regression (PLSR) method was used to predict deoxynivalenol (DON) content of samples and the cumulative toxin content: the sum of fumonisins (FB1, FB2) and DON content of samples. Based on the promising results of the study, HSI has the potential to be used as a preliminary testing method for mycotoxin content in feed materials.

The aflatoxin content of milk and dairy products as well as breast milk and the possibilities of detoxification

Aflatoxins are fungal toxins produced by Aspergillus species, which, due to increasing temperature and climate change in the temperate zone, appeared in the most important feeding plant and food ingredients. The most toxic of them is aflatoxin B1 (AFB1), which hydroxylates to aflatoxin M1 in the body of dairy animals and humans, and excretes in the milk. With the development of analytical methods, researchers are now able to detect toxins with a concentration of ng/kg. It was found that in most countries in Europe both breast milk and cow’s milk may contain AFM1, and therefore increased attention should be paid to the toxin content of milk, and that those above the limit should be excluded from consumption. In addition to cow’s milk, the AFM1 toxin content of breast milk can also be significant, the precursors of which are introduced into the mother’s body with food. Aflatoxins are highly resistant to physical, chemical, and microbiological effects, so the detoxification of foods, especially milk, is almost impossible. The best solution appears to be feeding the animals with toxin-free feeds or feeds containing toxins below the permitted limit, without giving opportunity to the toxins to enter the milk from the feed and from there into the human body.

Production of Paralytic Shellfish Toxins (PSTs) in Toxic Alexandrium catenella is Intertwined with Photosynthesis and Energy Production

To investigate the mechanism for the production of paralytic shellfish toxins (PST) in toxic dinoflagellates, with a 2D-gel based approach, we had made two sets of proteomic comparisons: (a) between a toxic Alexandrium catenella (AC-T) and a phylogenetically closely related non-toxic strain (AC-N), (b) between toxic AC-T grown in a medium with 10% normal amount of phosphate (AC-T-10%P) known to induce higher toxicity and AC-T grown in normal medium. We found that photosynthesis and energy production related proteins were up-regulated in AC-T when compared to AC-N. However, the same group of proteins was down-regulated in AC-T-10%P when compared to normal AC-T. Examining the relationship of photosynthesis and toxin content of AC-T upon continuous photoperiod experiment revealed that while growth and associated toxin content increased after 8 days of continuous light, toxin content maintained constant when cells were shifted from continuous light to continuous dark for 3 days. This emphasized the cruciality of light availability on toxin biosynthesis in AC-T, while another light-independent mechanism may be responsible for higher toxicity in AC-T-10%P compared to normal AC-T. Taken all together, it is believed that the interplay between “illumination”, “photosynthesis”, “phosphate availability”, and “toxin production” is much more complicated than what we had previously anticipated.

Effects of Nutrient Limitation on the Synthesis of N-Rich Phytoplankton Toxins: A Meta-Analysis

Eutrophication has played a major role in the worldwide increase of harmful algal blooms (HABs). Higher input of key nutrients, such as nitrogen (N) and phosphorus (P), can stimulate the growth of harmful algal species in freshwater, estuarine, and coastal marine ecosystems. Some HAB-forming taxa, particularly several cyanobacteria and dinoflagellate species, are harmful through the production of N-rich toxins that have detrimental effects on the environment and human health. Here, we test how changes in nutrient availability affect N-rich toxin synthesis in cyanobacteria and dinoflagellates using a meta-analysis approach. Overall, N-rich toxin content showed an increase with P limitation, while it tended to decrease with N limitation, but we also observed substantial variation in responses both within and across genera and toxin groups. For instance, in response to N limitation, microcystin content varied from a 297% decrease up to a 273% increase, and paralytic shellfish poisoning (PSP) toxin content varied from a 204% decrease to an 82% increase. Cylindrospermopsin, produced by N2-fixing cyanobacteria, showed no clear direction in response to nutrient limitation, and cellular contents of this compound may thus vary independently of nutrient fluctuations. Our results confirm earlier reported stoichiometric regulation of N-rich phytoplankton toxins, showing increased toxin content with an increase in cellular N:P ratios, and vice versa. Thus, changes in N-rich toxin content largely follow the changes in relative cellular N content. Consequently, although nutrient limitation may limit bloom biomass and thereby bloom toxicity, our results warn that P limitation can cause accumulation of cellular toxins and thus lead to unexpected increases in bloom toxicity.