Toxigenic Species Research Articles

Evaluation of the effects of temperature on processed coffee beans in the presence of fungi and ochratoxin A

The coffee bean is sensitive to contamination with ocratoxigenic fungi; temperature influences the growth, and germination of these fungi, as well as the fungal toxins produced. The objectives of this study were to assess the distribution of toxigenic species, analyze the concentration of ochratoxin A (OTA) in Arabica coffee beans, and aplicate a mathematical model that considers the influence of actual temperature to predict the effects of projected temperature increase on OTA production. This toxin was, however, not detected in any of the coffee bean species analyzed here. The species with the highest incidence were Aspergillus niger and Aspergillus ochraceus. The results of the mathematical model demonstrated the influence of temperature on the production of the toxin. This information indicates the distribution of toxigenic fungal species in the regions of coffee cultivation in Minas Gerais, and thus, will assist the producers in adopting preventive measures.Practical applicationsBrazil is the largest coffee producer and exporter, which makes it a leader in the global coffee market; the state of Minas Gerais is responsible for 50% of this production. Following the global trend, Brazil has regulated the maximum permissible limit for ochratoxin A in coffee beans. This has led to a great interest in monitoring fungi and toxin production, mainly during the postharvest stage in the coffee cultivation regions of Brazil. Preventive measures can aid in the safe production of coffee beans, and the use of mathematical models capable of predicting the growth and production of fungal toxins are fundamental to informing the producers of the most favorable conditions in terms of temperature, as well as increases in ambient temperature, in specific regions of interest.

Occurrence of Marine Biotoxins and Shellfish Poisoning Events and Their Causative Organisms in Argentine Marine Waters

In the Argentine Sea, marine phycotoxins of microalgal origin associated with five shellfish poisoning syndromes have been reported. The most problematic in terms of toxicity and geographic distribution is paralytic shellfish poisoning (PSP), followed by diarrhetic shellfish poisoning (DSP). In contrast, amnesic shellfish poisoning (ASP), spiroimine shellfish poisoning (SSP), and azaspiracid shellfish poisoning (AZP) have not been reported to cause human illness or closures of shellfish harvest sites in Argentina to date but pose a potential risk, as associated toxins and producing organisms are present in Southwest Atlantic waters and were detected at subregulatory levels in mollusks. Alexandrium catenella and Gymnodinium catenatum have been identified as producers of the PSP toxins C1/2, gonyautoxins (GTX1-4), saxitoxin (STX), and neosaxitoxin (NEO) in the Argentine Sea. Nine potentially toxigenic species of the diatom genus Pseudo-nitzschia have been reported for Argentinean coastal waters: P. australis, P. brasiliana, P. delicatissima, P. fraudulenta, P. multiseries, P. pseudodelicatissima, P. pungens, P. seriata, and P. turgidula, all of which are known to produce the neurotoxin domoic acid that causes ASP. Two genera have been identified as producers of DSP toxins in Argentina: the benthic dinoflagellate Prorocentrum lima and several species of the pelagic dinoflagellate genus Dinophysis: D. acuminata, D. caudata, D. fortii, D. norvegica, and D. tripos. The occurrence of these species in Argentine waters is associated with okadaic acid (OA), dinophysistoxin-1 (DTX-1), pectenotoxin-2 (PTX-2), and pectenotoxin-2 seco acid (PTX-2sa). Historically, yessotoxins (YTXs) were also included in DSP syndrome and all three known YTX-producers have been confirmed in Argentinean waters: Gonyaulax spinifera, Lingulodinium polyedra, and Protoceratium reticulatum, but of these only P. reticulatum could be associated with YTX production to date. Several species of the family Amphidomataceae, which cause AZP, have been reported for Argentina: Amphidoma languida, Azadinium dexteroporum, Az. luciferelloides, Az. poporum, and Az. spinosum. In Argentinean coastal waters, out of these species only Az. poporum has been identified as toxigenic to date, as it produces azaspiracid-2 (AZA-2) and its phosphorylated form. Currently in Argentina, seafood is monitored for the risk of ASP, AZP, DSP, and PSP.

Cryptic diversity within the Scytonema complex: Characterization of the paralytic shellfish toxin producer Heterosyctonema crispum, and the establishment of the family Heteroscytonemataceae (Cyanobacteria/Nostocales)

Strains of the freshwater filamentous, benthic cyanobacterium Scytonema crispum Agardh isolated from six sites in subtropical south-east Queensland were characterised using a combination of phenotypic and genetic traits. Morphologically, the strains were consistent with the description of Scytonemataceae sensu stricto, and the description of Scytonema crispum. However, phylogenetic analysis of the 16S rRNA gene, the 16S-23S rRNA operon, and the nifH gene revealed that these strains and three others from outside Australia formed a monophyletic clade distinct from Scytonema and other species in the Scytonemataceae. Collectively, this data suggests this group is sufficiently evolutionarily distinct to be placed in a new family, Heteroscytonemataceae fam. nov. Accordingly, the taxon previously known as S. crispum has been transferred to a new genus Heteroscytonema gen nov., as H. crispum. Some strains of H. crispum exhibited facultative production of paralytic shellfish toxins (PSTs). The concentration of PSTs produced by individual strains varied widely, from 2.7 μg g−1 to 171.3 μg g−1, and included C toxins, decarbamoyl saxitoxin (dcSTX), gonyautoxins (GTX2, GTX3 and GTX5), saxitoxin (STX) and uncharacterised PSTs. The majority of the Australian strains produced dcSTX as the dominant saxitoxin analogue, a significant finding given that dcSTX has approximately half the relative toxicity of STX. The PST profile varied within and between Australian strains of H. crispum and in strains collected from New Zealand and the United States. The sxtA gene, one of the determinants for the production of PSTs, was present in all strains in which PSTs were detected. The discovery of PST-producing H. crispum in the headwaters of a major drinking water reservoir presents a serious risk for potential human and animal exposure to these neurotoxic compounds and further highlights the importance of monitoring benthic cyanobacteria populations for potentially toxigenic species.

Chemical composition and antifungal activity of essential oils from Senecio nutans, Senecio viridis, Tagetes terniflora and Aloysia gratissima against toxigenic Aspergillus and Fusarium species

Essential oils from aerial parts of Senecio nutans, Senecio viridis, Tagetes terniflora and Aloysia gratissima were analysed by GC-MS and their antifungal activities were assayed on toxigenic Fusarium and Aspergillus species. Sabinene (27.6 ± 0.1%), α-phellandrene (15.7 ± 0.3%), o-cymene (9.6 ± 0.2%) and β-pinene (6.1 ± 0.2%) in S. nutans, 9,10-dehydrofukinone (92.7 ± 0.2%) in S. viridis, β-thujone (36.1 ± 0.1%), α-thujone (32.2 ± 0.2%), 1,8-cineol (10.7 ± 0.1%) and sabinene (6.2 ± 0.2%) in A. gratissima, and cis-tagetone (33.6 ± 0.2%), cis-β-ocimene (17.1 ± 0.2%), trans-tagetone (17.0 ± 0.1%), cis-ocimenone (8.0 ± 0.2%) and trans-ocimenone (8.2 ± 0.1%) in T. terniflora. The oils showed moderate antifungal activity (1.2 mg/mL > MIC >0.6 mg/mL) on the Fusarium species and a weak effect on Aspergillus species. The antifungal activity was associated on F. verticillioides to the high content of cis-tagetone, trans-tagetone, cis-β-ocimene, cis-ocimenone, trans-ocimenone and on F. graminearum due to the total content of oxygenated sesquiterpenes and 9,10- dehydrofukinone. The oil of S. viridis synergized the effect of fungicides and food preservatives on F. verticillioides.

Diversity and mycotoxin production by Fusarium temperatum and Fusarium subglutinans as causal agents of pre-harvest Fusarium maize ear rot in Poland

Maize ear rot is a common disease found worldwide, caused by several toxigenic Fusarium species. Maize ears and kernels infected by Fusarium subglutinans contained significant amounts of beauvericin, fusaproliferin, moniliformin, and enniatins. In 2011, F. subglutinans sensu lato has been divided into two species: Fusarium temperatum sp. nov. and F. subglutinans sensu stricto, showing different phylogeny and beauvericin production within the populations of maize pathogens in Belgium. Isolates of the new species—F. temperatum—were also identified and characterized in Spain, Argentina, Poland, France, and China as one of the most important pathogens of maize. Moreover, F. temperatum was proved to be pathogenic to maize seedlings and stalks. We identified Fusarium isolates obtained from diseased maize ears collected between 2013 and 2016 in Poland (321 isolates). Based on morphological analyses, six Fusarium species were identified. Molecular identification performed on the set of selected isolates (42 isolates) revealed 34 isolates to be F. temperatum and only five to be F. subglutinans. Interestingly, the phylogenetic analysis showed that the population of F. temperatum infecting maize in Poland remained quite uniform for over 30 years with only a few exceptions. For the first time, a single isolate of Fusarium ramigenum was detected from the area of Poland. Significant amounts of BEA were found in Fusarium-damaged kernels. The same kernel samples contained also enniatins A1, A, B1, and B. The results clearly demonstrate the occurrence of F. temperatum as maize pathogen in Poland for over the last three decades.

Antifungal activity of silver nanoparticles and simvastatin against toxigenic species of Aspergillus

Aspergillus spp. are ubiquitous fungi that grow on stored grains. Some species produce toxins that can harm human and animal health, leading to hepato- and nephrotoxicity, immunosuppression and carcinogenicity. Major fungicides used to prevent fungal growth may be toxic to humans and their repeated use over time increases levels of resistance by microorganisms. Nanotechnology is an emerging field that allows use of antimicrobial compounds in a more efficient manner. In this study, was evaluated the antifungal activity of biogenic silver nanoparticles (AgNPs, synthesized by fungi) and simvastatin (SIM, a semi-synthetic drug), alone and in combination against three toxigenic species belonging to the genera Aspergillus section Flavi (Aspergillus flavus, Aspergillus nomius and Aspergillus. parasiticus) and two of section Circumdati (Aspergillus ochraceus and Aspergillus melleus). SIM exhibited a MIC50 of 78 μg/mL against species of Section Flavi and a MIC50 of 19.5 μg/mL against species of Section Circumdati. The MIC50 of AgNPs against Aspergillus flavus, Aspergillus nomius and Aspergillus parasiticus was 8 μg/mL, while the MIC50 was 4 μg/mL against Aspergillus melleus and Aspergillus ochraceus. Checkerboard assay showed that these compounds, used alone and in combination, have synergistic and additive effects against toxicogenic species of Aspergillus. Analysis by SEM gives an idea of the effect of SIM and AgNPs alone and in combination on spore germination and vegetative growth. Ultrastructural analysis revealed that spore germination was prevented, or aberrant hyphae were formed with multilateral branches upon treatment with SIM and AgNPs. These results reveal potential benefits of using combination of AgNPs and SIM to control fungal growth.

Plankton Multiproxy Analyses in the Northern Patagonian Shelf, Argentina: Community Structure, Phycotoxins, and Characterization of Toxic Alexandrium Strains

The extensive Argentine continental shelf supports high plankton productivity and fish catches. In particular, El Rincon coastal area and the adjacent shelf fronts (38.5–42o S, 58.5–62o W) comprise diverse habitats and hold species of economic and ecological value. So far, studies of the microbial community at the base of the food web remain scarce. Here we describe the early spring plankton (>5-200 µm) structure in terms of abundance, biomass, species composition, functional groups and phycotoxin profiles in surface waters of El Rincon in September 2015. Diatoms were the most abundant and the largest contributors to carbon biomass at most stations. They dominated in coastal and inner-shelf (depths 20 µm) heterotrophic protists, e.g. various ciliates and dinoflagellates species were more abundant offshore. Scanning of phycotoxins in the field disclosed that paralytic shellfish poisoning (PSP) toxins were dominated by gonyautoxins-1/4 (GTX1/4). Lipophilic toxins were detected in low abundance, e.g. domoic acid (DA), although a bloom of Pseudo-nitzschia spp. (up to 3.6 x 105 cells L-1) was detected at inner-shelf stations. Pectenotoxin-2 (PTX-2) and 13-desmethyl spirolide C (SPX-1) were the most abundant in the field. PTX-2 co-occurred with Dinophysis spp., mainly D. tripos, while SPX-1 dominated at middle-shelf stations, where cells of Alexandrium catenella (1 strain) and A. ostenfeldii (3 strains) were isolated. The quantitative PSP profiles of the Alexandrium strains differed significantly from the field profiles. Moreover, the three A. ostenfeldii strains proved to be PSP producers and additionally produced 5 novel spirolides. Phylogenetic analyses of these first strains from the South Atlantic disclosed a new ribotype group suggesting a biogeographical distinction of the population. The plankton survey presented here contributes with baseline knowledge to evaluate potential ecosystem changes and to track the global distribution of toxigenic species.

Pseudo-nitzschia, Nitzschia, and domoic acid: New research since 2011

Some diatoms of the genera Pseudo-nitzschia and Nitzschia produce the neurotoxin domoic acid (DA), a compound that caused amnesic shellfish poisoning (ASP) in humans just over 30 years ago (December 1987) in eastern Canada. This review covers new information since two previous reviews in 2012. Nitzschia bizertensis was subsequently discovered to be toxigenic in Tunisian waters. The known distribution of N. navis-varingica has expanded from Vietnam to Malaysia, Indonesia, the Philippines and Australia. Furthermore, 15 new species (and one new variety) of Pseudo-nitzschia have been discovered, bringing the total to 52. Seven new species were found to produce DA, bringing the total of toxigenic species to 26.We list all Pseudo-nitzschia species, their ability to produce DA, and show their global distribution. A consequence of the extended distribution and increased number of toxigenic species worldwide is that DA is now found more pervasively in the food web, contaminating new marine organisms (especially marine mammals), affecting their physiology and disrupting ecosystems.Recent findings highlight how zooplankton grazers can induce DA production in Pseudo-nitzschia and how bacteria interact with Pseudo-nitzschia. Since 2012, new discoveries have been reported on physiological controls of Pseudo-nitzschia growth and DA production, its sexual reproduction, and infection by an oomycete parasitoid. Many advances are the result of applying molecular approaches to discovering new species, and to understanding the population genetic structure of Pseudo-nitzschia and mechanisms used to cope with iron limitation. The availability of genomes from three Pseudo-nitzschia species, coupled with a comparative transcriptomic approach, has allowed advances in our understanding of the sexual reproduction of Pseudo-nitzschia, its signaling pathways, its interactions with bacteria, and genes involved in iron and vitamin B12 and B7 metabolism.Although there have been no new confirmed cases of ASP since 1987 because of monitoring efforts, new blooms have occurred. A massive toxic Pseudo-nitzschia bloom affected the entire west coast of North America during 2015–2016, and was linked to a ‘warm blob’ of ocean water. Other smaller toxic blooms occurred in the Gulf of Mexico and east coast of North America. Knowledge gaps remain, including how and why DA and its isomers are produced, the world distribution of potentially toxigenic Nitzschia species, the prevalence of DA isomers, and molecular markers to discriminate between toxigenic and non-toxigenic species and to discover sexually reproducing populations in the field.

The occurrence of mycotoxigenic fungi in abalone feed in South Africa

Abalone feed in South Africa is mainly produced from locally sourced grains and has soy or fishmeal as a protein source. Contamination with fungal species associated with grain-based animal feed is, therefore, a predictable risk. Various Fusarium, Penicillium and Aspergillus species are known to produce mycotoxins when colonising grains. The aim of this study was to investigate the occurrence of toxigenic fungal species in the ingredients of compound abalone feeds as well as in final abalone-feed products. In this study, 248 fungal isolates were obtained from feed ingredients and compound abalone feeds collected from three different South African abalone farms and one feed supplier. Morphological and multigene phylogenetic analyses were used to identify the fungi isolated. Fusarium, Penicillium and Aspergillus species were consistently isolated. The presence of these species does not always result in mycotoxin contamination.

Fungal mycobiota and mycotoxin risk for traditional artisan Italian cave cheese

Cave cheese is a surface mold-ripened variety of cheese produced also in South of Italy, exploiting fungal population naturally occurring on cave walls, as part of secondary microbiota for ripening. In this study, 148 fungal strains were isolated from 22 independent cave cheese samples, collected in 13 Italian geographical locations, mostly in Apulian area.DNA-based identification showed the presence of twenty-four fungal species in the outer part of the cheese ripened in caves. Aspergillus westerdijkiae and Penicillium biforme resulted the most frequently isolated species, followed by Penicillium roqueforti and Penicillium solitum. The 86% of cheese sample presented at least one toxigenic species and the 45% revealed the presence of ochratoxigenic species, A. westerdijkiae and A. steynii, suggesting possible mycotoxin risk during ripening stage in caves, confirmed by the presence of ochratoxin A (OTA) in the rind of 36% of samples.In conclusion, cave cheese is a susceptible product for toxigenic mold growth and in particular OTA contamination, therefore adeguate scientific tools for matching organolectic consumer expectations and complete safety of food should be developed, as well as spontaneously molded and not monitored cheeses should not be consumed to avoid mycotoxin risk.

A New Concept to Secure Food Safety Standards against Fusarium Species and Aspergillus Flavus and Their Toxins in Maize.

Commercial maize hybrids are exposed to different degrees of ear infection by toxigenic fungal species and toxin contamination. Their resistance to different fungi and toxin relationships are largely unknown. Without this knowledge, screening and breeding are not possible for these pathogens. Seven- to tenfold differences were found in resistance to Fusarium spp., and there was a five-fold difference in ear coverage (%) in response to A. flavus. Three hybrids of the twenty entries had lower infection severity compared with the general means for toxigenic species. Three were highly susceptible to each, and 14 hybrids reacted differently to the different fungi. Differences were also observed in the toxin content. Again, three hybrids had lower toxin content in response to all toxigenic species, one had higher values for all, and 16 had variable resistance levels. Correlations between infection severity and deoxynivalenol (DON) content were 0.95 and 0.82 (p = 0.001) for F. graminearum and F. culmorum, respectively. For fumonisin and F. verticillioides ear rot, the Pearson correlation coefficient (r) was 0.45 (p = 0.05). Two independent isolates with different aggressiveness were used, and their mean X values better described the resistance levels. This increased the reliability of the data. With the introduction of this methodological concept (testing the resistance levels separately for different fungi and with two isolates independently), highly significant resistance differences were found. The resistance to different fungal species correlated only in certain cases; thus, each should be tested separately. This is very useful in registration tests and post-registration screening and breeding. This would allow a rapid increase in food and feed safety.

Aflatoxin Contamination of Dried Insects and Fish in Zambia

Dried insects and fish are important sources of income and dietary protein in Zambia. Some aflatoxin-producing fungi are entomopathogenic and also colonize insects and fish after harvest and processing. Aflatoxins are carcinogenic, immune-suppressing mycotoxins that are frequent food contaminants worldwide. Several species within Aspergillus section Flavi have been implicated as causal agents of aflatoxin contamination of crops in Africa. However, aflatoxin producers associated with dried fish and edible insects in Zambia remain unknown, and aflatoxin concentrations in these foods have been inadequately evaluated. The current study sought to address these data gaps to assess potential human vulnerability through the dried fish and edible insect routes of aflatoxin exposure. Caterpillars ( n = 97), termites ( n = 4), and dried fish ( n = 66) sampled in 2016 and 2017 were assayed for aflatoxin by using lateral flow immunochromatography. Average aflatoxin concentrations exceeded regulatory limits for Zambia (10 μg/kg) in the moth Gynanisa maja (11 μg/kg), the moth Gonimbrasia zambesina (Walker) (12 μg/kg), and the termite Macrotermes falciger (Gerstacker) (24 μg/kg). When samples were subjected to simulated poor storage, aflatoxins increased ( P < 0.001) to unsafe levels in caterpillars (mean, 4,800 μg/kg) and fish ( Oreochromis) (mean, 23 μg/kg). The L strain morphotype of A. flavus was the most common aflatoxin producer on dried fish (88% of Aspergillus section Flavi), termites (68%), and caterpillars (61%), with the exception of Gynanisa maja, for which A. parasiticus was the most common (44%). Dried fish and insects supported growth (mean, 1.3 × 109 CFU/g) and aflatoxin production (mean, 63,620 μg/kg) by previously characterized toxigenic Aspergillus section Flavi species, although the extent of growth and aflatoxigenicity depended on specific fungus-host combinations. The current study shows the need for proper storage and testing of dried insects and fish before consumption as measures to mitigate human exposure to aflatoxins through consumption in Zambia.

Occurrence and Frequency of Outdoor and Indoor Airborne Fungi of Suez General Hospital, Suez, Egypt

This study aimed to determine the occurrence and frequency of fungi in the outdoor and indoor (reception and intensive care) air of Suez General Hospital as well as to investigate the antifungal activity of some volatile oils against isolated toxigenic species. Samples were collected through passive sedi-mentation using settle plate method. Sabouraud dextrose agar (SDA) plates were exposed to air and incubated at 28°C for 7 days. 39 species represents 13 fungal genera were isolated from the outdoor and indoor air and the most common genera were Aspergillus, Penicillium, Cladosporium, Alternaria, and Rhizopus. The total colony forming units of airborne fungi of the outdoor, reception, and intensive care unit (ICU) were 2063.25, 1395.15, and 884.25 CFU/m3, respectively. Aspergillus flavus recorded the highest occurrence with the highest frequency in the outdoor and indoor air and produced aflatoxins B1 and B2. Cinnamon essential oil showed high antifungal activity against the isolated toxigenic fungi and its fumigation inhibited the germination of spores of these fungi.

Molecular interaction of antifungal compounds with fungal type I Polyketide synthase and preventing hepatocarcinogenesis

Background: The type I fungal iterative Polyketide synthase (PKS) is found in many toxigenic Aspergillus species. PKS is an important biological non- reducing (NR) type enzymes. It possesses highly active Acyl Carrier Protein (ACP) domain that is implicated in thiol ester-bound intermediates in involved in fungal polyketides, fatty acids and other non-ribosomal peptides formation. These natural polyketide and fatty acids are participated in formation of aflatoxin biosynthesis. These aflatoxins are highly responsible for hepatocarcinhgenesis (HCC), one of commonest cancer among humans living in tropical regions. The HCC has also been shown the synergetic effect with viral infections especially hepatitis B. The risk of HCC is drastically increased under episodic exposure of aflatoxin contaminated feed and hepatitis B that can be fatal if delay in diagnosis and proper treatment. Methods & Materials: The ACP domain as 3D coordinates 2KR5.pdb of polyketide synthase of Aspergillus parasiticus is taken from RCSB. The requisite antifungal ligand files for docking purpose i.e. neoeriocitrin (CID: 114627), blasticidin-S (CID: 16380), blasticidin-S hydrochloride (CID: 258) and pipernomaline (CID: 9974595) protein were retrieved from PubChem Database. The protein preparation, ligand library preparation, sites identification and docking (LibDock Score) were performed by using dynamic software Discovery Studio version 3.5. Results: In the three different sites, site 1 (x: -7.589; y: -2.949; z: 4.007) shown the most effective docking results. At this site 1, the highest LibDock score of 160.282 for 2KR5- neoeriocitrin had shown the successful inhibition of polyketide synthase. Lys4, Asp80, Gly84, Gly86, Asp87 and Gly89 are the amino acides of the protein that are interacted with neoeriocitrin. Conclusion: The Computational study and prediction of three different active sites in ACP domain of PKS of Aspergillus parasiticus had shown the successful interaction with proper ligands. The neoeriocitrin and similar other organic compounds are the very effective flavonoid found in grape fruits that can essentially use in treating HCC and Hepatitis patients.

Effects of salinity variation on growth and yessotoxin composition in the marine dinoflagellate Lingulodinium polyedra from a Skagerrak fjord system (western Sweden)

The marine dinoflagellate Lingulodinium polyedra is a toxigenic species capable of forming high magnitude and occasionally harmful algal blooms (HABs), particularly in temperate coastal waters throughout the world. Three cultured isolates of L. polyedra from a fjord system on the Skagerrak coast of Sweden were analyzed for their growth characteristics and to determine the effects of a strong salinity gradient on toxin cell quotas and composition. The cell quota of yessotoxin (YTX) analogs, as determined by liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS), ranged widely among strains. For two strains, the total toxin content remained constant over time in culture, but for the third strain, the YTX cell quota significantly decreased (by 32%) during stationary growth phase. The toxin profiles of the three strains differed markedly and none produced YTX. The analog 41a-homo-YTX (m/z 1155), its putative methylated derivative 9-Me-41a-homo-YTX (m/z 1169) and an unspecified keto-YTX (m/z 1047) were detected in strain LP29-10H, whereas strain LP30-7B contained nor-YTX (m/z 1101), and two unspecified YTX analogs at m/z 1159 and m/z 1061. The toxin profile of strain LP30-8D comprised two unspecified YTX analogs at m/z 1061 and m/z 991 and carboxy-YTX (m/z 1173). Strain LP30-7B cultured at multiple salinities (10, 16, 22, 28 and 34) did not tolerate the lowest salinity (10), but there was a statistically significant decrease (by 21%) in toxin cell quota between growth at the highest versus lower permissible salinities. The toxin profile for strain LP30-7B remained constant over time for a given salinity. At lower salinities, however, the proportion of the unspecified YTX analog (m/z 1061) was significantly higher, especially with respect to nor-YTX (m/z 1101). This study shows high intra-specific variability in yessotoxin composition among strains from the same geographical region and inconsistency in toxin cell quota under different environmental regimes and growth stages in culture. This variation has important implications for the kinetics of YTX production and food web transfer in natural bloom populations from diverse geographical regions.

Characterisation of the Mycobiota on the Shell Surface of Table Eggs Acquired from Different Egg-Laying Hen Breeding Systems.

Microbial safety is an important factor contributing to the egg quality. During egg acquisition, there is significant risk of contamination of the eggshell surface with microscopic fungi. Mycelial hyphae may grow on the eggshell surface and penetrate into the egg content. However, there is no information on the populations of microscopic fungi on the eggshell surface and, consequently, on possible production of mycotoxins. Therefore, the aim of the study was to identify the species of microscopic fungi present on the eggshell surface acquired from different breeding systems and to measure the number of selected mycotoxins. The qualitative analysis resulted in the identification of 41 isolates on the surface of eggs. There were 7 isolates from the organic production system, 11 from the free-range production system, 14 from the deep litter indoor housing system and 9 from the cage farming production system. The research proved that the diversification in the population of mycobiota on the eggshells depended on the egg-laying hen breeding system. The microscopic fungi isolated from the eggshells included toxigenic and pathogenic species such as Fusarium culmorum and F. equiseti. As the egg storage time increased, fungi, including the pathogenic species, penetrated through the eggshells. In consequence, mycotoxins were identified in the egg whites. Type-A and type-B trichothecenes were found in the eggshell samples containing F. culmorum.

Potential effects of mechanically removing macrophytes on the phytoplankton community of a subtropical reservoir

ABSTRACT Intensive growth of aquatic macrophytes interferes with water quality and ecosystem dynamics worldwide. Although mechanically removing macrophytes is the most commonly used method for their eradication, it can also cause undesirable disturbances in aquatic reservoir communities. We performed laboratory incubations of phytoplankton sampled before and after macrophytes were mechanically removed from the Piraquara II reservoir, South Brazil. We analyzed changes in growth and composition of the main phytoplankton groups with respect to nutrient shifting. Prior to removing the macrophytes, the phytoplankton community was dominated by low cell abundances of diatoms and flagellates. In contrast, growth rates of cyanobacteria (mainly Cylindrospermopsis raciborskii, Pseudanabaena sp., and Geitlerinema sp.) and of colonial chlorophytes were favored after macrophyte removal, while the abundances of diatoms and flagellates decreased. Our results suggest that removing macrophytes causes dramatic changes in phytoplankton composition and biomass and selects for toxigenic species of cyanobacteria. These changes were probably associated with the disturbance caused by removing the macrophytes, which immediately created new environmental conditions prone to species competition. These findings indicate that the use of mechanical techniques to manage macrophytes should be carefully considered, along with monitoring of harmful species and changes of limnological parameters.

Isolation and identification ofVibriospecies in the Rio Bravo/Grande and water bodies from Reynosa, Tamaulipas

Water quality is associated with public health, as it plays an important role in the transmission and epidemiology of pathogens such as Vibrio, since this species have been responsible for human diseases around the world. This study demonstrated the presence of toxigenic Vibrio species in water bodies in Reynosa surroundings, indicating that water bodies may be a source of public health risk.

Aspergillus species and mycotoxins: occurrence and importance in major food commodities

Aspergillus species produce important mycotoxins, in particular aflatoxins, produced by A. flavus and related species, and ochratoxin A, produced by A. ochraceus and related species and also A. carbonarius and (less commonly) A. niger. In this review we briefly discuss the distribution of toxigenic Aspergillus species in nuts, coffee and cocoa beans, dried fruits, grapes, maize, rice and small grains. Future perspectives of distribution of Aspergillus species in foods are briefly discussed taking into account the impacts of climate change and the resilience of these mycotoxigenic species.

Toxigenic Alternaria species: impact in cereals worldwide

Alternaria is one of the main mycotoxigenic fungal genera found in cereals worldwide. Reports of black point and leaf blight diseases associated with Alternaria on cereals are continually published and recent studies have shown the possible and significant impact their toxins may have on human health. Although, cereal grains are constantly affected by Alternaria spp. and their toxins, still little relevance is given on the subject. At the moment, tenuazonic acid in sorghum/millet-based infant food is the only Alternaria toxin regulated by an official government authority (Bavarian health and food safety authority). This review reports the complex Alternaria species taxonomy, their prevalence and ability to produce a diverse group of mycotoxins and their impact on cereal grains worldwide.