A novel approach for mycotoxigenic fungi identifications based on uncomplicated microscopy and mycotoxin characters

Species concepts within fungi are (a) subject to frequent revision and (b) unusually protean. However, this allows novel schemes some scope to be considered. The taxonomy of the penicillia is unstable particularly in the important antibiotic and mycotoxin-producing subgenus Penicillium. Non-specialists in particular encounter difficulty with assigning names to taxa. Name changes of important fungi have occurred frequently and recently. There are difficulties relating identifications to mycotoxin production. This is necessary for controlling mycotoxin contamination in food, drink, homes, etc. Patulin is an important mycotoxin produced by various fungi and has strict limits in the European Union and elsewhere. Also, it is a useful model mycotoxin per se. The mycotoxin and/or the isoepoxydon dehydrogenase (IDH) gene of the metabolic pathway have been assessed in 318 strains predominately of subgenus Penicillium. These data were used to classify the isolates, although the applied aspects of the scheme are emphasised over the purely taxonomic. Of course, the issue of whether to apply a dual nomenclature to different states of pleomorphic fungi is relevant. Subgenus Penicillium contained most of the IDH and patulin positives. Many of species contained positive and negative members, which demonstrates that identifications based on morphology do not indicate patulin production. The species and varieties in subgenus Penicillium which have been associated with patulin production can be reduced to one name, viz. Penicillium Pen p+, where p is the abbreviation of patulin. This basic concept has been extended to other mycotoxin producing fungi within the subgenus using published data to indicate the utility of the scheme. The classification will lead naturally to the number of taxa being reduced. In addition, more meaningful results are obtained in terms of assessing the potential for patulin production. The possibilities of direct analysis of environmental samples are also discussed. The scheme could be used with advantage for other fungi.Fundação para a Ciência e a Tecnologia (FCT) - grant SFRH/BPD/14923/2004

Active emigration from climate change-caused seawater intrusion into freshwater habitats

Ecological risk assessment associated with seawater intrusions has been supported on the determination of lethal/sublethal effects following standard protocols that force exposure neglecting the ability of mobile organisms to spatially avoid salinized environments. Thus, this work aimed at assessing active emigration from climate change-caused seawater intrusion into freshwater habitats. To specific objectives were delineated: first, to compute median 12-h avoidance conductivities (AC50,12h) for freshwater species, and second, to compare it with literature data (LC50,48 or 96h, EC50,6 or 21d) to assess the relevance of the inclusion of stressor-driven emigration into risk assessment frameworks. Four standard test species, representing a broad range of ecological niches - Daphnia magna, Heterocypris incongruens, Danio rerio and Xenopus laevis - were selected. The salt NaCl was used as a surrogate of natural seawater to create the saline gradient, which was established in a 7-compartment system. At each specific LC50, 48 or 96h, the proportion of avoiders were well above 50%, ranging from 71 to 94%. At each LC50, considering also avoiders, populations would decline by 85-97%. Furthermore, for D. magna and X. laevis it was noticed that at the lowest conductivities eliciting mortality, the avoidance already exceeded 50%. The results showed that the emigration from salinity-disturbed habitats exists and that can even be more sensitive than standard endpoints. Looking solely to standard endpoints involving forced exposure may greatly underestimate the risk of local population extinction, because habitat function can be severely disrupted, with subsequent stressor-driven emigration, before any adverse physiological effects at the organism level. Thus, the present study highlights the need to include non-forced exposure testing into ecological risk assessment, namely of salinity-menaced costal freshwaters.publishe

Why do food and drink smell like earth?

Fungi have long been associated with earthy odours. One of the main contributors to this odour is geosmin, a sesquiterpenoid metabolite produced by soil living fungi. Some food commodities are liable to contamination by geosmin producing fungi. Under favourable environmental conditions the production of geosmin occurs. One of the producers of geosmin in fruits is Penicillium expansum which also produces the mycotoxin patulin. Recent reports indicate that geosmin production by P. expansum is stimulated by Botrytis cinerea. However, the effect on patulin production is not known. The above issues will be discussed in this contribution.Fundação para a Ciência e a Tecnologia (FCT

Teratogenic, oxidative stress and behavioural outcomes of three fungicides of natural origin (Equisetum arvense, mimosa tenuiflora, thymol) on zebrafish (danio rerio)

The improper use of synthetic fungicides has raised public concerns related to environmental pollution and animal health. Over the years, plant-derived antifungals have been investigated as safer alternatives, although little scientific evidence of its neurodevelopmental effects exist. The main objective of this study was to explore the effects of three alternative natural extracts (Equisetum arvense, Mimosa tenuiflora, Thymol) with antifungal properties during the early development of zebrafish by evaluating different teratogenic, oxidative stress and behavioural outcomes. Following the determination of the 96 h-LC50, exposure to sublethal concentrations showed the safety profile of both E. arvense and M. tenuiflora. However, following 96-h exposure to Thymol, increased lethality, pericardial oedema, yolk and eye deformations, and decreased body length were observed. The reduced and oxidized glutathione (GSH:GSSG) ratio was increased, and the glutathione-s-transferase activity in the group exposed to the highest Thymol concentration. Overall, these results support a more reducing environment associated with possible effects at the cellular proliferation level. In addition, the disruption of behavioural states (fear-and anxiety-like disorders) were noted, pointing to alterations in the c-Jun N-terminal kinase developmental signalling pathway, although further studies are required to explore this rationale. Notwithstanding, the results provide direct evidence of the teratogenic effects of Thymol, which might have consequences for non-target species.This research was funded by European Investment Funds by FEDER/COMPETE/POCI– Operational Competitiveness and Internationalization Programme, under the project POCI-01–0145-FEDER-006958 and National Funds by FCT—“Fundação para a Ciência e a Tecnologia”, under the project UIBD/04033/2020 and under the PhD grant number SFRH/BD/144904/2019

An applied identification scheme for penicillium

The goal is to provide an objective and practical identification scheme for Penicillium by using patulin as an example. The taxonomy of penicillia is unstable particularly in the important antibiotic and mycotoxin-producing subgenus Penicillium. Nonspecialists especially encounter difficulty with assigning names. Name changes of important fungi have occurred frequently and recently: There are difficulties relating identifications to mycotoxin production. This is necessary for controlling mycotoxin contamination in food, etc. Patulin is an important mycotoxin which has strict limits in the USA, European Union and elsewhere. Patulin and/or the isoepoxydon dehydrogenase (IDH) gene of the metabolic pathway have been analysed in 318 strains of Penicillium. The procedures involved predominately TLC and the PCR. These data were used to classify the isolates, although the applied aspects of the scheme are emphasised. Subgenus Penicillium contained most of the IDH and patulin positives. Many of the taxa were represented by positive and negative IDH and patulin detection included within each species. Numerous species were included in each category of patulin detection, IDH detection, etc. The species and varieties in subgenus Penicillium which are associated with patulin production can be reduced to one name, viz. Penicillium Penicillium patulin positive. This can be abbreviated to, Penicillium Penpat+. Other examples are Penicillium PenIDH+; Penicillium PenIDH+pat+. The occurrence of positive and negative detection within species demonstrates that identifications based on morphology do not necessarily indicate patulin production. The classification will lead naturally to the number of taxa being reduced dramatically. In addition, more meaningful results are obtained in terms of the potential for patulin production. The identification can accommodate quantitative data, and the concept could be extended usefully to other fungi. Identifications will be useful particularly to those attempting to identify weak spots in food commodity systems

Solutions to penicillium taxonomy crucial to mycotoxin research and health

The stability of taxonomy within Penicillium is reviewed with respect to mycotoxin production. Identification remains difficult despite the availability of modern methods. Proficiency testing is rare and conventional identifications do not inform reliably as to whether mycotoxins were detected/produced. A solution which consists of identifying a Penicillium strain as terverticillate and then undertaking mycotoxin analysis is described.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BPD/14923/200

Recovery of the proteose peptone component 3 from cheese whey in Reppal PES 100/polyethylene glycol aqueous two-phase systems

Recovery of the proteose peptone component 3 from cheese whey was optimal using a 16% (w/w) Reppal PES 100 – 24% (w/w) PEG 600 aqueous two-phase system, at pH 7, giving a mass recovery yield of 99% and a purity of 83% for proteose peptone component 3 in the upper phase. Using the above system a partition coefficient of 30.7 and a purification factor of 6.9 were achieved