Fullerol C60(OH)24 Nanoparticles Affect Secondary Metabolite Profile of Important Foodborne Mycotoxigenic Fungi In Vitro

Despite the efforts to control mycotoxin contamination worldwide, extensive contamination has been reported to occur in food and feed. The contamination is even more intense due to climate changes and different stressors. This study examined the impact of fullerol C₆₀(OH)₂₄ nanoparticles (FNP) (at 0, 1, 10, 100, and 1000 ng mL^-1) on the secondary metabolite profile of the most relevant foodborne mycotoxigenic fungi from genera Aspergillus, Fusarium, Alternaria and Penicillium, during growth in vitro. Fungi were grown in liquid RPMI 1640 media for 72 h at 29 °C, and metabolites were investigated by the LC-MS/MS dilute and shoot multimycotoxin method. Exposure to FNP showed great potential in decreasing the concentrations of 35 secondary metabolites; the decreases were dependent on FNP concentration and fungal genus. These results are a relevant guide for future examination of fungi-FNP interactions in environmental conditions. The aim is to establish the exact mechanism of FNP action and determine the impact such interactions have on food and feed safety.

Evaluation of Commercial Soybean Cultivars for Reaction to Phomopsis Seed Decay

Phomopsis seed decay (PSD), caused by Phomopsis longicolla (syn. Diaporthe longicolla), is an economically important soybean disease causing poor seed quality. Planting resistant cultivars is one of the most effective means to control PSD. In this study, 16 commercially available maturity groups IV and V soybean cultivars, including two previously identified PSD-resistant and two PSD-susceptible checks, were evaluated for seed infection by P. longicolla in inoculated and noninoculated plots, and harvested promptly or with a 2-week delay in harvest. The test was conducted at Stoneville, Mississippi, in 2012 and 2013. Seed infection by P. longicolla ranged from 0.5 to 76%, and seed germination ranged from 18 to 97%. One MG IV cultivar (Morsoy R2 491) and five MG V cultivars (Progeny 5650, Progeny 5706, Asgrow 5606, Asgrow 5831, and Dyna-Gro33C59) had significantly (P ≤ 0.05) lower percent seed infected by P. longicolla than their respective susceptible checks and other cultivars in the same tests. Information obtained from this study will be useful for soybean growers and breeders for selection of cultivars for planting or breeding and future genetic studies in the development of cultivars with improved resistance to PSD.

Symbiotic performance and induction of systemic resistance against Cercospora sojina in soybean plants co-inoculated with Bacillus sp. CHEP5 and Bradyrhizobium japonicum E109

Soybean is an economically very important crop throughout the word and particularly in Argentina. Soybean yield may be affected by many factors such as the lack of some essential nutrients or pathogens attack. In this work we demonstrated that the co-inoculation of the native biocontrol bacterium Bacillus sp. CHEP5 which induces resistance against Cercospora sojina in soybean and the nitrogen fixing strain Bradyrhizobium japonicum E109, was more effective in reducing frog leaf spot severity than the inoculation of the biocontrol agent alone. Probably, this is related with the increase in the ability to form biofilm when both bacteria are growing together. Furthermore, Bacillus sp. CHEP5 inoculation did not affect Bradyrhizobium japonicum E109 symbiotic behavior and flavonoids composition of root exudates in pathogen challenged plants. These results suggest that co-inoculation of plants with rhizobia and biocontrol agents could be a strategy to improve soybean production in a sustainable system.

Antimicrobial activity of pomegranate peel extracts as affected by cultivar

BACKGROUND

Some studies have reported that different parts of the pomegranate fruit, especially the peel, may act as potential antimicrobial agents and thus might be proposed as a safe natural alternative to synthetic antimicrobial agents. The high tannin content, especially punicalagin, found in pomegranate extracts, has been reported as the main compound responsible for such antimicrobial activity. Because the pomegranate peel chemical composition may vary with the type of cultivar (sweet, sour-sweet and sour), pomegranates may also differ with respect to their antimicrobial capacity.

RESULTS

The extract from PTO8 pomegranate cultivar peel had the highest antimicrobial activity, as well as the highest punicalagins (α and β) and ellagic acid concentrations. In the results obtained from both antibacterial and antifungal activity studies, the sour-sweet pomegranate cultivar PTO8 showed the best antimicrobial activity, and the highest ellagic acid concentrations.

CONCLUSION

The results of the present study suggest that ellagic acid content has a significant influence on the antimicrobial activity of the pomegranate extracts investigated. The pomegranate peel of the PTO8 cultivar is a good source of antifungal and antibacterial compounds, and may represent an alternative to antimicrobial agents of synthetic origin. © 2016 Society of Chemical Industry.

Seasonal and spatial variation of Deuteromycetes population in polluted cost of Kiaochow Bay

OBJECTIVE

To reveal the relationship between Deuteromycetes community and the environmental in Kiaochow Bay of the Yellow Sea.

METHODS

Using recorded pollution survey, we used molecular methods to study seasonal and spatial variation of Deuteromycetes community diversity in different polluted waters of Kiaochow Bay of the Yellow Sea, China.

RESULTS

Denaturing gradient gel electrophoresis fingerprints varied obviously among different sites of similar level of pollution. Moreover, sequence analysis of recovered dominant bands exhibited the existence of plenty of uncultivable fungi, among which Penicillium was the dominant genus. Furthermore, in heavily polluted estuary, there were abundant animal pathogens such as amoeba and Pythium as well as Deuteromycetes. These discoveries demonstrate that the Deuteromycetes community structure is closely related to marine environment, and are indicative of different level of marine contamination.

CONCLUSION

The relationship between Deuteromycetes community and different level of pollution and seasons varied were closely related.

[Advances in the regulation of cephalosporin C biosynthesis - A review]

The beta-lactam antibiotic cephalosporin C is produced industrially by Acremonium chrysogenum. Its derivative 7-aminocephalosporanic acid (7-ACA) is the intermediate of most chemical modification cephalosporins that are the most frequently used antibiotics for the therapy of infectious diseases. Due to its importance, the biosynthetic pathway of cephalosporin C has been elucidated in Acremonium chrysogenum. To improve the yield of cephalosporin C and reduce the cost of production, recent studies have been focused on the sophisticated regulation of cephalosporin C biosynthesis. In this review, recent advances in cephalosporin C biosynthesis and regulation are summarized.

Analytical Methods for Secondary Metabolite Detection

The entomopathogenic fungi Metarhizium brunneum, Beauveria bassiana, and B. brongniartii are widely applied as biological pest control agent in OECD countries. Consequently, their use has to be flanked by a risk management approach, which includes the need to monitor the fate of their relevant toxic metabolites. There are still data gaps claimed by regulatory authorities pending on their identification and quantification of relevant toxins or secondary metabolites. In this chapter, analytical methods are presented allowing the qualitative and quantitative analysis of the relevant toxic B. brongniartii metabolite oosporein and the three M. brunneum relevant destruxin (dtx) derivatives dtx A, dtx B, and dtx E.

[11beta-Hydroxylation of 6alpha-Fluoro-16alpha-Methyl-Deoxycorticosterone 21-Acetate by filamentous fungi]

Selected filamentous fungi--98 strains of 31 genera--were screened for the ability to catalyze 11beta-hydroxylation of 6alpha-fluoro-16alpha-methyl-deoxycorticosterone 21-acetate (FM-DCA). It was established that representatives of the genera Gongronella, Scopulariopsis, Epicoccum, and Curvularia have the ability to activate 11beta-hydroxylase steroids. The strains of Curvularia lunata VKM F-644 and Gongronella butleri VKM F-1033 expressed maximal activity and formed 6lpha-fluoro-16alpha-methyl-corticosterone as a major bioconversion product from FM-DCA. The structures of the major products and intermediates of the bioconversion were confirmed by TLC, H PLC, MS and 1H NMR analyses. Different pathways of 6alpha-fluoro-16alpha-methyl-corticosterone formation by C. lunata and G. butleri strains were proposed based on intermediate identification. The constitutive character and membrane-binding localization were evidence of a 11beta-hydroxylating system in G. butleri, while an inducible character and microsomal localization was confirmed for 11beta-hydroxylase of C. lunata. Under optimized conditions, the molar yield of 6alpha-fluoro-16alpha-methyl-corticosterone reached 65% at a FM-DCA substrate loading of 6 g/L.

Cadmium-induced formation of sulphide and cadmium sulphide particles in the aquatic hyphomycete Heliscus lugdunensis

Freshwater fungi which can survive under metal exposure receive increasing scientific attention. Enhanced synthesis of sulphide and glutathione but no phytochelatin synthesis in response to cadmium (up to 80 μM Cd(2+) in the medium) was measured in the aquatic hyphomycete Heliscus lugdunensis. Up to 25 μmol g(-1) dry mass the fungus formed sulphide in an exponentially Cd(2+)-concentration-dependent manner. Using light microscopy, precipitates were observed outside of the hyphae which could be determined as amorphous particles by X-ray diffraction (XRD). Energy dispersive X-ray spectroscopy (EDS) analysis indicated that these particles were mainly composed of Cd and S with an atomic ratio of 1:1, but some elements of the culture medium such as P and Cl were also present. Fungal cells exposed to Cd(2+) accumulated 12-28 μmol metal g(-1) dry mass over a period of 7-28 days. The results may indicate that sulphide could sequester excess Cd(2+) under oxygen deprived conditions and thereby reduce its toxicity via an additional avoidance mechanism of this fungus.

Effects of fungal inocula and habitat conditions on alder and eucalyptus leaf litter decomposition in streams of northern Spain

We investigated how fungal decomposer (aquatic hyphomycetes) communities colonizing alder and eucalyptus leaf litter respond to changes in habitat characteristics (transplantation experiment). We examined the breakdown of leaf materials and the associated fungal communities at two contrasting sites, a headwater stream (H) and a midreach (M). Agroforestry increased from headwater to midreach. One month after the start of experiments at both sites, some leaf samples from the midreach site were transplanted to the headwater site (M-H treatment). Although both sites showed similar dissolved inorganic nutrient concentrations, eucalyptus leaves initially incubated at the midreach site (M, M-H) increased their breakdown rate compared to those incubated along the experiment at the headwater site (H). Alder breakdown rate was not enhanced, suggesting that their consumption was not limited by nutrient availability. Sporulation rates clearly differed between leaf types (alder > eucalyptus) and streams (H > M), but no transplantation effect was detected. When comparing conidial assemblages after transplantation, an inoculum effect (persistence of early colonizing species) was clear in both leaf species. Substrate preference and shifts in the relative importance of some fungal species along the process were also observed. Overall, our results support the determining role of the initial conditioning phase on the whole litter breakdown process, highlighting the importance of intrinsic leaf characteristics and those of the incubation habitat.

Incubation temperature and substrate quality modulate sporulation by aquatic hyphomycetes

Frequency and amplitude of temperature oscillations can profoundly affect structure and function of ecosystems. Unless the rate of a biological process changes linearly within the range of these fluctuations, the cumulative effect of temperature differs from the effect measured at the average temperature (Jensen's inequality). Here, we measured numbers and types of spores released by aquatic hyphomycetes from oak and alder leaves that had been exposed in a Portuguese stream for between 7 and 94 days. Recovered leaves were incubated at four temperatures between 5 and 20 °C. Over this range, the sporulation response to temperature was decelerating, with an estimated optimum around 12.5 °C. Assuming a linear response, therefore, overestimates spore release from decaying leaves. The calculated discrepancy was more pronounced with recalcitrant oak leaves (greater toughness, phenolics concentration, lower N and P concentration than alder), and reached 26.6 % when temperature was assumed to oscillate between 1 and 9 °C, rather than remaining constant at 5 °C. The maximum fluctuation of water temperature over 48 h during the field experiment was approximately 3 °C, which would result in a discrepancy of up to 6 %. The composition of the fungal community (assessed by species identification of released spores) was significantly influenced by the state of decomposition, but not by leaf species or temperature. When quantifying the potential impact of global change on aquatic fungal communities, the average increase as well as fluctuations of the temperature have to be considered.

The impact of proteomics on the understanding of functions and biogenesis of fungal extracellular vesicles

Several microbial molecules are released to the extracellular space in vesicle-like structures. In pathogenic fungi, these molecules include pigments, polysaccharides, lipids, and proteins, which traverse the cell wall in vesicles that accumulate in the extracellular space. The diverse composition of fungal extracellular vesicles (EV) is indicative of multiple mechanisms of cellular biogenesis, a hypothesis that was supported by EV proteomic studies in a set of Saccharomyces cerevisiae strains with defects in both conventional and unconventional secretory pathways. In the human pathogens Cryptococcus neoformans, Histoplasma capsulatum, and Paracoccidioides brasiliensis, extracellular vesicle proteomics revealed the presence of proteins with both immunological and pathogenic activities. In fact, fungal EV have been demonstrated to interfere with the activity of immune effector cells and to increase fungal pathogenesis. In this review, we discuss the impact of proteomics on the understanding of functions and biogenesis of fungal EV, as well as the potential role of these structures in fungal pathogenesis. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.

An alkaline thermostable recombinant Humicola grisea var. thermoidea cellobiohydrolase presents bifunctional (endo/exoglucanase) activity on cellulosic substrates

Humicola grisea var. thermoidea is a deuteromycete which secretes a large spectrum of hydrolytic enzymes when grown on lignocellulosic residues. This study focused on the heterologous expression and recombinant enzyme analysis of the major secreted cellulase when the fungus is grown on sugarcane bagasse as the sole carbon source. Cellobiohydrolase 1.2 (CBH 1.2) cDNA was cloned in Pichia pastoris under control of the AOX1 promoter. Recombinant protein (rCBH1.2) was efficiently produced and secreted as a functional enzyme, presenting a molecular mass of 47 kDa. Maximum enzyme production was achieved at 96 h, in culture medium supplemented with 1.34 % urea and 1 % yeast extract and upon induction with 1 % methanol. Recombinant enzyme exhibited optimum activity at 60 °C and pH 8, and presented a remarkable thermostability, particularly at alkaline pH. Activity was evaluated on different cellulosic substrates (carboxymethyl cellulose, filter paper, microcrystalline cellulose and 4-para-nitrophenyl β-D-glucopyranoside). Interestingly, rCBH1.2 presented both exoglucanase and endoglucanase activities and mechanical agitation increased substrate hydrolysis. Results indicate that rCBH1.2 is a potential biocatalyst for applications in the textile industry or detergent formulation.

Purification and characterization of Hb 98-114: a novel hemoglobin-derived antimicrobial peptide from the midgut of Rhipicephalus (Boophilus) microplus

The antimicrobial activity of hemoglobin fragments (hemocidins) has been reported in a variety of models. The cattle tick Rhipicephalus (Boophilus) microplus is a blood sucking arthropod from where the first in vivo-generated hemocidin was characterized (Hb 33-61). In the present work we identified a novel antimicrobial peptide from the midgut of fully engorged R. (B.) microplus females, which comprises the amino acids 98-114 of the alpha subunit of bovine hemoglobin, and was designated Hb 98-114. This peptide was active against several yeast and filamentous fungi, although no activity was detected against bacteria up to 50μM of the synthetic peptide. Hb 98-114 was capable of permeabilizing Candida albicans cell membrane and had a fungicidal effect against this yeast. Circular dichroism (CD) and nuclear magnetic resonance (NMR) experiments showed that Hb 98-114 has a random conformation in aqueous solution but switches to an alpha-helical conformation in the presence of sodium dodecyl sulfate (SDS). This alpha helix adopts an amphipathic structure which may be the mechanism of cell membrane permeabilization. Importantly, Hb 98-114 may play an important role in defending the tick midgut against fungal pathogens and is the first hemocidin with specific antifungal activity to be characterized.

[Screening and identification of high-yield poly(β-malic acid) bacterial strain]

OBJECTIVE

To isolate and identify the high-yield poly-malic acid (PMLA) bacterial strains from the nature.

METHODS

Samples were collected and cultured. The high-yield PMLA bacterial strains were screened through morphological observation, qualitative PMLA tests by HPLC and ITS sequence analysis on the isolated bacterial strains.

RESULTS

A high-yield PMLA strain II 04 was isolated, the yield of PMLA of the strain reached to 26.23g/L in the rotary shaker at 25 degree for 7d. From morphological observation and ITS sequences analysis, the strain belonged to Aureobasidium pullulans, and named as Aureobasidium pullulans ZUCC-41.

CONCLUSION

A high-yield bacterial strain has been isolated from the nature and identified to be Aureobasidium pullulans.

[Herbicide activity of some micromycetes]

Screening of phytotoxic properties of 5 micromycete strains were made concerning cultivated plants and weeds. All of the strains show phytotoxic activity of different levels. In particular, the cultural filtrates of Penicillium sp. 10-51 and Aspergillus niveus 2411 suppressed the growth of seeds of Galinsoga parviflora, Amaranthus retroflexus and Capsella bursa pastoris. The cultural filtrate of Ulocladium consortiale 960 suppressed the growth of Panicum capillare and Setaria viridis. The greatest phytotoxic activity was shown by the cultural filtrates of Myrothecium cinctum 903 and 910, on the one hand, both of them suppressed the growth of seeds of E. virgata completely, but, on the other hand, they did not take any effect on the seeds of radish.

[Biodegradation of polyhydroxyalkanoates by soil microbiocoenoses of different structures and detection of microorganisms-destructors]

Biodegradation of microbial linear polymers of hydroxyalkanoic acids (polyhydroxyalkanoates, PHAs) by soil microbiocoenoses of different structures has been studied during two field seasons in different weather conditions. This process was shown to be influenced by the polymer chemical composition, temperature, humidity, and the microbial soil component. The PHA degradation was accompanied by a decrease in the polymer molecular weight and an increase in the degree of crystallinity, indicating the preferential destruction of the amorphous phase compared to the crystalline one. The quantity of the true PHA destructors developing at the surface of the polymer samples was lower than the quantity of accompanying bacteria. The dominant PHA destructors under the test conditions were identified as bacteria of the genera Variovorax, Stenotrophomonas, Acinetobacter, Pseudomonas, Bacillus, and Xanthomonas and as micromycetes from Penicillium, Paecilomyces, Acremonium, Verticillium. and Zygosporium.

Influence of various growth parameters on fungal growth and volatile metabolite production by indoor molds

A Penicillium polonicum, an Aspergillus ustus and a Periconia britannica strain were isolated from water-damaged environments and the production of microbial volatile organic compounds (MVOCs) was investigated by means of headspace solid-phase microextraction followed by GC-MS analysis. The most important MVOCs produced were 2-methylisoborneol, geosmin and daucane-type sesquiterpenes for P. polonicum, 1-octen-3-ol, 3-octanone, germacrene D, δ-cadinene and other sesquiterpenes for A. ustus and the volatile mycotoxin precursor aristolochene together with valencene, α-selinene and β-selinene for P. britannica. Different growth conditions (substrate, temperature, relative humidity) were selected, resembling indoor parameters, to investigate their influence on fungal metabolism in relation with the sick building syndrome and the results were compared with two other fungal strains previously analyzed under the same conditions. In general, the range of MVOCs and the emitted quantities were larger on malt extract agar than on wallpaper and plasterboard, but, overall, the main MVOC profile was conserved also on the two building materials tested. The influence of temperature and relative humidity on growth and metabolism is different for different fungal species, and two main patterns of behavior could be distinguished. Results show that, even at suboptimal conditions for growth, production of fungal volatiles can be significant.

[Enzyme immunoassay of the secondary metabolites of micromycetes as components of lichen substances]

The composition of low-molecular biologically active metabolites typical of microscopic fungi has been studied in blastemas of fruticose lichens of the genera Cladonia, Cetraria, Evernia, Bryoria, and Usnes. The enzyme immunoassay method showed the presence of sterigmatocystin, emodin, mycophenolic acid, citrinin, alternariol, and diacetoxyscirpenol, which occurred regularly and, in most cases, at a frequency of 55 to 100%. The highest levels of accumulation were 0.001-0.003% for emodin, 0.0002% for alternariol and citrinin, 0.0001% for sterigmatocystin and mycophenolic acid, and 0.00005% of the weight of air-dry material for diacetoxyscirpenol. Other metabolites (cyclopiazonic acid, ergot alkaloids, ochratoxin A, PR toxin, deoxynivalenol, zearalenone, and fumonisins) were detected in these lichens less frequently (sometimes only upon the expansion of the territory of sampling), and their content was no more than 0.00005%. The peculiarities of the component composition and the levels of accumulation of fungal metabolites in lichens of different taxonomic affiliation were discussed.

The ectopic expression of a pectin methyl esterase inhibitor increases pectin methyl esterification and limits fungal diseases in wheat

Cell wall pectin methyl esterification can influence plant resistance because highly methyl-esterified pectin can be less susceptible to the hydrolysis by pectic enzymes such as fungal endopolygalacturonases (PG). Pectin is secreted into the cell wall in a highly methyl-esterified form and, here, is de-methyl esterified by pectin methyl esterase (PME). The activity of PME is controlled by specific protein inhibitors called PMEI; consequently, an increased inhibition of PME by PMEI might modify the pectin methyl esterification. In order to test the possibility of improving wheat resistance by modifying the methyl esterification of pectin cell wall, we have produced durum wheat transgenic lines expressing the PMEI from Actinidia chinensis (AcPMEI). The expression of AcPMEI endows wheat with a reduced endogenous PME activity, and transgenic lines expressing a high level of the inhibitor showed a significant increase in the degree of methyl esterification. These lines showed a significant reduction of disease symptoms caused by the fungal pathogens Bipolaris sorokiniana or Fusarium graminearum. This increased resistance was related to the impaired ability of these fungal pathogens to grow on methyl-esterified pectin and to a reduced activity of the fungal PG to hydrolyze methyl-esterified pectin. In addition to their importance for wheat improvement, these results highlight the primary role of pectin despite its low content in the wheat cell wall.

Effects of 4-n-nonylphenol on aquatic hyphomycetes

We measured the removal of 4-n-nonylphenol (between 50 and 500 μg L(-1)) from an aqueous solution with or without linden and oak leaf disks. More 4-n-NP was removed when the leaves were first exposed for 3 weeks in a stream, which allowed colonization by aquatic hyphomycetes. The response of fungal sporulation rates from beech, linden, maple and oak leaves to increasing levels of 4-n-NP was complex. Linear regressions were non-significant, arguing against a no-threshold model. The response at the lowest concentration (50 μg L(-1)) was between 7% (beech) and 67% (maple) higher than in the absence of 4-n-NP, however, the difference was not significant. The number of sporulating species of aquatic hyphomycetes was significantly higher at the lowest concentration than in the control treatment without 4-n-NP. The composition of the fungal community was affected by leaf species but not by 4-n-NP concentration. The results suggest the presence of a weak hormeotic effect. The known ability of aquatic hyphomycetes and other fungi to degrade nonylphenols and related substances, combined with fungal resilience in their presence, makes decaying leaves potential candidates for bioremediation.

[Influence of different types of ionizing radiation on fatty acid profiles of cell lipids in microscopic fungi with radioadaptive properties]

The fatty acid profiles of strains of dark-pigmented (melanin-containing) species Cladosporium cladosporioides and Hormoconis resinae, and light-pigmented Aspergillus versicolor and Paecilomyces lilacinus, showing radioadaptive properties in comparison with control strains of the same species, which did not have such properties and the influence on them of two (121Sn; 137Cs) types of ionizing radiation have been studied. It was established that the most important fatty acids were hexadecanoic acid (C16:0), octadecanoic acid (C18:0), octadecenoic acid (C18:1) and octadecadienoic acid (C18:2). The strains, showing radioadaptive properties in comparison with control differed in the relative concentrations of saturated and unsaturated fatty acids and some minor components. The two types of radiation had different influence on the fatty acid profiles of the investigated strains. At dark-pigmented species C. cladosportoides, H. resinae the fatty acid unsaturation rate was higher, at strains showing radioadaptive properties (0.98) as against control ones (0.73; 0.9), and at light-pigmented species A. versicolor and P lilacinus--it was lower at strains with radioadaptive properties (1.00; 0.83) as against control ones (1.08; 0.92). The paper is presented in Ukrainian.

[Anaerobic growth ability and alcohol fermentation activity of microscopic fungi]

The method proposed in this study was used to isolate fungi grown under anaerobic conditions and to reveal distinctions in their abundance and species composition in different habitats. The ability of micromycetes of different taxa to grow under anaerobic conditions and ensure alcohol fermentation was determined for a representative sample (344 strains belonging to more than 60 species). The group of fungi growing under anaerobic conditions included species with high, moderate, and low fermentation activity. The ability for anaerobic growth and fermentation depended on the taxonomic affiliation of fungi. In some cases, the expression of these characteristics depended on the habitat from which the strain was isolated. The maximum level of ethanol accumulation in culture liquid (1.2-4.7%) was detected for Absidia spinosa, Aspergillus sp. of group flavus, Aspergillus terreus, Acremonium sp., Mucor circinelloides, Mucor sp., Fusarium oxysporum, F. solani, F. sambucinum, Rhizopus arrhizus var. Arrhizus, Trichoderma atroviride, and Trichoderma sp.

[Producers of mycophenolic acid in ensiled and grain feeds]

Using the reaction of activated N-hydrooxisuccinimide ester of mycophenolic acid, a series of immunoreactive conjugated antigens with albumins, gelatin, and glucosoxidase is obtained. On the basis of polyclonal rabbit antibodies, a test-system for indirect competitive immunoenzyme analysis is elaborated, which has the sensitivity 0.4 ng/ml. By immunoanalysis, the ability for active biosynthesis of mycophenolic acid in strains of Byssochlamys nivea (44/44, 4100-68400 ng/ml) and Penicillium roqueforti (7/16, 204-25120 ng/ml) from the mycobiota of ensiled feeds is confirmed. The correspondence between weakly expressed producing capacity of most species of fungi of the genera Penicillium and Aspergillus prevailing in grain feeds and the data on low occurrence of this metabolite in grain (8.0%) and combined feeds (11.9%) is confirmed. A potential relationship between particular cases of a significant accumulation of mycophenolic acid (from 500 to 1500 microg/kg) in grains of wheat, corn, and combined feeds and a high biosynthetic activity in rare species P. puberulum, P. stoloniferum, and P. gladioli is discussed.

Recent advancements in the biosynthetic mechanisms for polyketide-derived mycotoxins

Polyketides (PKs) are a large group of natural products produced by microorganisms and plants. They are biopolymers of acetate and other short carboxylates and are biosynthesized by multifunctional enzymes called polyketide synthases (PKSs). This review discusses the biosynthesis of four toxic PK, aflatoxins, fumonisins, ochratoxins (OTs), and zearalenone. These metabolites are structurally diverse and differ in their mechanisms of toxicity. However, they are all of concern in food safety and agriculture because of their toxic properties and their frequent accumulation in crops used for food and feed. The focus is on the recent advancements in the understanding of the molecular mechanisms for the biosynthesis of these mycotoxins. Several of the mycotoxin PKSs have been genetically and biochemically studied while other PKSs remain to be investigated. Multiple post-PKS modifications are often required for the maturation of the mycotoxins. Many of these modification steps for aflatoxins and fumonisins are well established while the post-PKS modifications for zearalenone and OTs remain to be biochemically characterized. More efforts are needed to completely illustrate the biosynthetic mechanisms for this important group of PKs.

Phytoremediation of petroleum-polluted soils: application of Polygonum aviculare and its root-associated (penetrated) fungal strains for bioremediation of petroleum-polluted soils

Petroleum-polluted soils are a common disaster in many countries. Bioremediation of oil contamination in soils is based on the stimulation of petroleum-hydrocarbon-degrading fungal and microbial communities. A field study was conducted in a petroleum-contaminated site to find petroleum-resistant plants and their root-associated fungal strains for use in bioremediation of petroleum-polluted soils. Results and observations showed that the amounts of petroleum pollution in nonvegetated soils were several times higher than in vegetated soils. Plants collected from petroleum-polluted areas were identified using morphological characters. Results indicated that seven plant species were growing on the contaminated sites: Alhaji cameleron L. (Fabaceae), Amaranthus retroflexus L. var. retroflexus (Amaranthaceae), Convolvulus arvensis L. (Convolvulaceae), Chrozophora hierosolymitana Spreg. (Euphorbiaceae), Noea mucronata L. (Boraginaceae), Poa sp. (Poaceae), and Polygonum aviculare L. (Polygonaceae). The root-associated fungi of each plant were determined and results showed the presence of 11 species that associated with and also penetrated the roots of plants growing in the polluted areas. Altenaria sp. was common to all of the plants and the others had species-specific distribution within the plants. The largest numbers of fungal species (six) were determined for P. aviculare and Poa sp. in polluted areas. However, the variation of fungal strains in the plants collected from petroleum-polluted areas was greater than for nonpolluted ones. Culture of fungi in oil-contaminated media showed that all the studied fungi were resistant to low petroleum pollution (1% v/v) and a few species, especially Fusarium species, showed resistance to higher petroleum pollution (10% v/v) and may be suitable for bioremediation in highly polluted areas. Bioremediation tests with P. aviculare, with and without fungal strains, showed that application of both the plant and its root-associated fungal strains was more effective than of the plant and fungi separately, and Fusarium species were the most effective. Results indicated that fungal strains had the main role in bioremediation of petroleum-polluted soils, but plant roots enhanced the process.

Environmental factors and interactions with mycobiota of grain and grapes: effects on growth, deoxynivalenol and ochratoxin production by Fusarium culmorum and Aspergillus carbonarius

Mycotoxigenic fungi colonizing food matrices are inevitably competing with a wide range of other resident fungi. The outcomes of these interactions are influenced by the prevailing environmental conditions and the competing species. We have evaluated the competitiveness of F. culmorum and A. carbonarius in the grain and grape food chain for their in vitro and in situ dominance in the presence of other fungi, and the effect that such interactions have on colony interactions, growth and deoxynivalenol (DON) and ochratoxin A (OTA) production. The Index of Dominance shows that changes in water activity (a_w) and temperature affect the competitiveness of F. culmorum and A. carbonarius against up to nine different fungi. Growth of both mycotoxigenic species was sometimes inhibited by the presence of other competing fungi. For example, A. niger uniseriate and biseriate species decreased growth of A. carbonarius, while Aureobasidium pullulans and Cladosporium species stimulated growth. Similar changes were observed when F. graminearum was interacting with other grain fungi such as Alternaria alternata, Cladopsorium herbarum and Epicoccum nigrum. The impact on DON and OTA production was very different. For F. culmorum, the presence of other species often inhibited DON production over a range of environmental conditions. For A. carbonarius, on a grape-based medium, the presence of certain species resulted in a significant stimulation of OTA production. However, this was influenced by both temperature and a_w level. This suggests that the final mycotoxin concentrations observed in food matrices may be due to complex interactions between species and the environmental history of the samples analyzed.

[Evaluation of micromycetes potential concerning synthesis of biologically active substances]

Screening of 41 cultures of some researched strains of micromycetes by their antibiotic and phytotoxic activities in relation to different test-organisms--Gram-positive, Gram-negative, phytopathogenic bacteria, yeasts and green algae was conducted. The wide spectrum of antibiotic action was characterized for the cultures of Gliocladium catenulatum 2709, 3942 Penicillium vulpinum 3957, Ulocladium atrum 1889, U.consortiale 960, Trithirachium album 2673. A fungistatic activity was shown by only two strains U. consortiale 960 and Nectria inventa 3949. A small group consisted of cultures with high phytotoxic activity: P. vulpimum 3957, U. atrum 1889, U. consortiale 960, N. inventa 3949, Eupenicillium parvum 3128, Bipolaris sorokinia 4080, Paecilomyces lilacinus 1428, 1492, T. album 2673. They showed the activity in relation to the majority of test-cultures of the green algae. We consider two cultures: U. consortiale 960 and P. vulpinum 3957 to be the most promising for further researches, they differ by a wide spectrum of antibiotic and phytotoxic activity and were not studied before. The paper is presented in Ukrainian.

[Hyphomycetes as organisms producing cyclodepsipeptides]

The review deals with cyclodepsipeptides produced by hyphomycetes. The cyclodepsipeptide compounds are prospective new agents for the treatment of diseases of the infectious and pathophysiologic nature.

Arsenic hyperaccumulation by Pteris vittata and Pityrogramma calomelanos: a comparative study of uptake efficiency in arsenic-treated soils and waters

This work comprised of the comparative study of arsenic (As) uptake efficiency by Pteris vittata and Pityrogramma calomelanos grown in (i) As amended soils (0-600 ppm) and (ii) As tainted water (40 ppb) using a new compact continuous flow phytofiltration system in a tropical greenhouse. The As hyperaccumulation efficiency was dependent on the growth medium for the two fern species. The highest level of As detected in the fronds of P. vittata was 19,300+/-190 ppm (dry weight basis) and 11,600+/-230 ppm for Pityrogramma calomelanos, after growing for 78 days in soils amended with As. In the compact continuous flow As phytofiltration system experiments, Pityrogramma calomelanos was found to perform better than P. vittata in phytofiltrating As contaminated water under waterlogged conditions. During the 167 h of phytofiltration experiment, the removal efficiency was approximately 99% and 67% for Pityrogramma calomelanos and P. vittata systems respectively, based on an initial 40 ppb As. Pityrogramma calomelanos also required a shorter acclimatization time than P. vittata under waterlogged conditions.

Fungal diversity in composting process of pig manure and mushroom cultural waste based on partial sequence of large subunit rRNA

Fungal diversity during composting was investigated by culture-independent rDNA sequence analysis. Composting was carried out with pig manure and mushroom cultural waste using a field-scale composter (Hazaka system), and samples were collected at various stages. Based on partial sequence analysis of large subunit (LSU) ribosomal RNA (rRNA) and sequence identity values, a total of 12 different fungal species were found at six sampling sites; Geotrichum sp., Debaryomyces hansenii, Monographella nivalis, Acremonium strictum, Acremonium alternatum, Cladosporium sphaerospermum, Myriangium durosai, Pleurotus eryngii, Malassezia globosa, Malassezia restricta, Rhodotorula glutinis, and Fusarium sporotrichioides. Geotrichum sp. of the class Saccharomycetes was the most predominant fungal species throughout the composting process (185 out of a total of 236 identified clones, or 78.4%), followed by Acremonium strictum (7.6%), Monographella nivalis (5.1%), and Pleurotus eryngii (3.8%). The prevalence of Geotrichum sp. was the lowest (61.1%) at the beginning of composting, and then gradually increased to 92.5% after 10 days of composting.

Metabolites from the endophytic mitosporic Dothideomycete sp. LRUB20

The endophytic mitosporic Dothideomycete sp. LRUB20 was found to produce pyrone derivatives, dothideopyrones A-D (1, 3, 4, and 5), together with seven known compounds, including questin (9), asterric acid (10), methyl asterrate (11), sulochrin (12), and eugenitin (13), 6-hydroxymethyleugenitin (14), and cis, trans-muconic acid (15). Dothideopyrone D (5) and its acetate derivative 6 exhibited moderate cytotoxic activity. This is the first report on a naturally occurring muconic acid, which is commonly known as a biomarker in environments after exposure to benzene and phenol (or derivatives). Interestingly, the LRUB20 fungus could produce muconic acid in relatively high yield (47.8mg/L). The utility of endophytic fungi in the field of white biotechnology is discussed.

[Cercospora kikuchii isolated from Province of Santa Fe (Argentina): genetic variability and cercosporin production]

The aims of the present study were to analyze the genetic variability of Cercospora kikuchii isolates and the in vitro cercosporin production, of these isolates obtained from soybean at the central-northern region of Santa Fe province (Argentina). Also the relationship between RAPD profiles and toxin production was also assessed. The strain C. kikuchii NBRC 6711 and 13 soybean isolates with symptoms of leaf blight were tested. Cercosporin production was analyzed by growing the fungus on Potato Dextrose Agar, extracting the toxin in alkaline medium and determining its concentration by spectrophotometry. The population of C. kikuchii studied showed variability, both genotypically, nine different groups were encountered, and have the ability to produce cercosporin. No relationship was found between toxin production and the RAPD profiles.

Characterisation of uranium(VI) sorption by two environmental fungal species using gamma spectrometry

Uranium(VI) sorption by two highly uranium-resistant air-borne fungi in a low-pH medium was measured by means of gamma spectrometry. Growth kinetics and stoichiometry of the two fungal species were also studied. Results show acceptable growth rates in synthetic medium with glucose and ammonia as carbon and nitrogen sources, respectively. Typical oxidative metabolism of carbohydrates was found. In vivo uptake of the radionuclide was negligible, but biosorption dry biomass presented a remarkable performance. The fungal strains showed potential for use in bioremediation.

Conidia production ofBeauveria sp. by solid-state fermentation for biocontrol ofIlex paraguariensis caterpillars

Conidia production of Beauveria sp. strain LAG by solid-state fermentation (SSF) using blends of agro-industrial residues (residual potatoes and sugar-cane bagasse) was optimized with respect to cultivation conditions and the composition of substrate mixture in Erlenmeyer flasks and column-type bioreactor. With a blend of 60 % residual potatoes and 40 % sugar-cane bagasse the optimum conditions achieved were: incubation temperature 26 degrees C, initial substrate pH 6, inoculum concentration 10(7) conidia per g substrate; optimal initial moisture of the substrate was 70 % for Erlenmeyer flasks, in column-type bioreactor (with forced aeration) the optimal initial moisture of the substrate was 65 % with airflow of 60 mL/min. The highest production (1.07 x 10(10) conidia per g dry substrate) was achieved after a 10-d fermentation. The conidia were used in laboratory assays against Thelosia camina and Hylesia sp., caterpillars that are serious pests of mate plants. The mortality of T. camina was >90 % 10 d after spraying caterpillars with 1 mL conidia suspension at a concentration 10(5)-10(8)/mL. For Hylesia sp., the mortality was 70 %, 7 d after immersion in the conidia suspension containing 108 conidia per mL. Therefore, the Beauveria sp. LAG can be considered to be an important biocontrol instrument in the prospect of the Integrated Pest Management for mate plants.

Enzyme-controlled reactions giving alkanols of use in the synthesis of biologically active molecules

(+/-)-Bicyclo[3.2.0]hept-2-en-6-one was reduced using a variety of fungi including yeasts. Baker's yeast gave 6-exo-(1R,5S,6S)-bicyclo[3.2.0]hept-2-en-6-ol and 6-endo-(1S,5R,6S)-bicyclo[3.2.0]hept-2-en-6-ol while Curvularia lunata and Mortierella ramanniana gave only the 6-endo-alcohol and optically active bicycloheptenone. The optically active bicycloheptenols were used to prepare prostaglandin F2 alpha in the natural configuration.

Removal of humic substances by biosorption

Fungal pellets of Aspergillus niger 405, Aspergillus ustus 326, and Stachybotrys sp. 1103 were used for the removal of humic substances from aqueous solutions. Batchwise biosorption, carried out at pH 6 and 25 degrees C, was monitored spectrophotometrically and the process described with Freundlich's model. Calculated sorption coefficients K(f) and n showed that A. niger exhibited the highest efficiency. A good match between the model and experimental data and a high correlation coefficient (R2) pointed out to judicious choice of the mechanism for removal of humic substances from the reaction medium. The sorption rate constants (k) for A. ustus and Stachybotrys sp. were almost equal, however higher than that for A. niger. Comparison of test results with the simulated ones demonstrated the applicability of the designed kinetic model for removal of humic substances from natural water by biosorption with fungal pellets. Different morphological structure of the examined fungal pellets showed that faster sorption does not imply the most efficient removal of humic substances. Desorption of humic substances from fungal pellets was complete, rapid, and yielded uniform results.

Optimization of culture medium for lactosucrose ( G-beta-D-galactosylsucrose) Production by Sterigmatomyces elviae mutant using statistical analysis

In this study, the optimization of culture medium using a Sterigmatomyces elviae mutant was investigated using statistical analysis to increase the cell mass and lactosucrose ((4)G-beta-D-galactosylsucrose) production. In basal medium, the cell mass and lactosucrose production were 4.12 g/l and 140.91 g/l, respectively. However, because of the low cell mass and lactosucrose production, optimization of culture medium was carried out to increase the cell mass and lactosucrose production. Culture media were optimized by the S. elviae mutant using analysis of variance (ANOVA) and response surface methodology (RSM). Central composite designs using RSM were utilized in this investigation. Quadratic models were obtained for cell mass and lactosucrose production. In the case of cell mass, optimal components of the medium were as follows: sucrose 1.13%, yeast extract 0.99%, bactopeptone 2.96%, and ammonium sulfate 0.40%. The predicted maximum value of cell mass was about 5.20 g/l and its experimental value was 5.08 g/l. In the case of lactosucrose production, optimal components of the medium were as follows: sucrose 0.96%, yeast extract 1.2%, bactopeptone 3.0%, and ammonium sulfate 0.48%. Then, the predicted maximum value of lactosucrose production was about 194.12 g/l and the corresponding experimental value was about 183.78 g/l. Therefore, by culturing using predicted conditions, the real cell mass and lactosucrose production increased to 23.3% and 30.42%, respectively.

Mycoflora and natural occurrence of aflatoxins and fumonisin B1 in cassava and yam chips from Benin, West Africa

The presence of fungi, aflatoxins and fumonisin B1 in cassava and yam chips (during 28 processing and storage) were evaluated during two consecutive seasons in two agroecological zones of Benin (Northern Guinea Savannah, NGS and Sudan Savannah, SS). The Benin samples were assessed for moisture content, fungal infestation and total aflatoxin and fumonisin B1 contamination. During the two seasons, samples collected from the NGS, had moisture contents ranging from 10.0 to 14.7% in cassava chips and from 11.4 to 15.3% in yam chips. In samples from the SS, moisture content ranged from 10.1 to 14.5% and 11.1 to 14.5% in cassava and yam chips, respectively. A. flavus was the predominant fungal species. The maximum cfu/g in cassava and yam chips was 8950 and 6030, respectively. Other fungal species isolated included P. chrysogenum, M. piriformis, Phoma sorghina, F. verticillioides, R. oryzae and Nigrospora oryzae. High performance liquid chromatography analysis of both cassava and yam chips showed no contamination by either aflatoxins or fumonisin B1.

4-ethylphenol and 4-ethylguaiacol in wines: estimating non-microbial sourced contributions and toxicological considerations

Analyses of commercially available wines suggested non-Brettanomyces sources of 4-ethylphenol and 4-ethylguaiacol. Grapes, enological additions, exposure to plastics, and oak-barrel aging were potential inputs considered. Investigations of whole grape bunch samples from two major red wine Vitis vinifera cultivars (L. cv. Cabernet Franc and Pinot Noir), a commercial mannoprotein additive, and three commercial enological tannin additions indicated they are not likely significant sources of these compounds. Studies on 15 commercial oak barrelled red wines from six Vitis vinifera cultivars (L. cv. Cabernet Franc, Cabernet Sauvignon, Dunkelfelder, Merlot, Pinot Meunier, and Pinot Noir), and a review of volatile phenol extraction from toasted oak wood, suggested that oak-aging may produce concentrations of up to 50 microg L(-1) 4-ethylphenol and 4-ethylguaiacol. Thus, following potential Brettanomyces-sourced aroma impacts in wine using 4-ethylphenol and/or 4-ethylguaiacol concentrations as proxies should only be considered reliable at analyte levels>100 microg L(-1). A review of worldwide 4-ethylphenol and 4-ethylguaiacol concentrations in wine, consumption patterns, and available toxicological data also suggested that levels of 4-ethylphenol being observed in wines worldwide do not warrant concerns about acute or long-term effects. While little is known about the toxicology of 4-ethylguaiacol, it is unlikely that elevated concentrations will pose any health-related concerns.

Production of mycotoxins by Aspergillus lentulus and other medically important and closely related species in section Fumigati

The production of mycotoxins and other secondary metabolites have been studied by LC-DAD-MS from six species in Aspergillus section Fumigati. This includes the three new species Aspergillus lentulus, A. novofumigatus and A. fumigatiaffinis as well as A. fumigatus, Neosartoria fisheri and N. pseudofisheri. A major finding was detection of gliotoxin from N. pseudofisheri, a species not previously reported to produce this mycotoxin. Gliotoxin was also detected from A. fumigatus together with fumagillin, fumigaclavine C, fumitremorgin C, fumiquinazolines, trypacidin, methyl-sulochrin, TR-2, verruculogen, helvolic acid and pyripyropenes. Major compounds from A. lentulus were cyclopiazonic acid, terrein, neosartorin, auranthine and pyripyropenes A, E and O. Thus in the present study A. fumigatus and A. lentulus did not produce any of the same metabolites except for pyripyropenes. The fact that A. lentulus apparently does not produce gliotoxin supports the idea that other compounds than gliotoxin might play an important role in the effective invasiveness of A. lentulus. An overall comparison of secondary metabolite production by strains of the six species was achieved by analysis of fungal extracts by direct injection mass spectrometry and cluster analysis. Separate groupings were seen for all the six species even though only one isolate was included in this study for the two species A. novofumigatus and A. fumigatiaffinis.

IB-01212, a new cytotoxic cyclodepsipeptide isolated from the marine fungus Clonostachys sp. ESNA-A009

IB-01212, a new cytotoxic cyclodepsipeptide featuring C2 symmetry, was isolated from the mycelium extract of Clonostachys sp. ESNA-A009. The amino acid sequence of the compound was determined by spectroscopy techniques. The absolute configuration of the amino acids was determined by a combination of the Marfey and menthol methods. The structure, which was confirmed by comparison of the analytical data for the natural product with a sample obtained by solid-phase peptide synthesis, was revealed to be a cyclic dimer formed by two chains of L-N,N-Me2Leu-L-Ser-L-N-MeLeu-L-N-MePhe bound by the two esters formed between the carboxylic acid of the L-N-MePhe and the hydroxyl function of the L-Ser. IB-01212 is highly cytotoxic to different tumor cell lines.

Hongos toxicogénicos contaminantes de frutos de alpataco

Fungi contaminant of alpataco (Prosopis flexuosa) fruits from La Pampa province (Argentina) were identified. Alternaria alternata and Sphaeropsis sapinea were the dominant species. Phoma sp., Nigrospora sp., Preussia minima, Cladosporium sp., Pithomyces chartarum, Epicoccum nigrum, Aspergillus niger and Aspergillus speluneus were also isolated but with less frequency. Twelve strains of Alternaria alternata, the toxigenic species with higher incidence, were screened for alternariol (AOH), alternariol monomethyl ether (AME) and tenuazonic acid (TA) production. Since one isolate was able to produce AME, six isolates produced AOH and AME and two isolates produced AOH, AME and TA, these results indicate a potential risk of contamination with Alternaria toxins in this substrate.

[Detection of fungal metabolites showing toxic activity through Artemia salina bioassay]

The aim of this study was to detect toxic metabolites from fungi contaminating food and medicinal herbs by applying the toxicity assay to Artemia salina. According to toxicity percentages, the extracts were classified as nontoxic (NT), slightly toxic (ST), toxic (T) and highly toxic (HT). Those classified as T and HT were assayed for mycotoxins. Only 6 out of 71 strains were found to be T (8.5%) for A. salina. Penicillium brevicompactum Dierckx, isolated from sausages, was found to be HT, mainly due to the presence of ochratoxin A and two other unidentified metabolites.

Cadmium and heat response of the fungus Heliscus lugdunensis isolated from highly polluted and unpolluted areas

Induction of heat shock protein (Hsp) 70 and distinct metallothionein-like proteins (MTLPs) in response to Cd and heat treatment were studied in two strains of the aquatic hyphomycete Heliscus lugdunensis: Hl-H4, isolated from a heavy metal polluted site, and Hl-BB taken from an unpolluted area. Upon Cd-exposure, Hsp70 was actively synthesized in the strain Hl-H4, and to a much lower degree in the strain Hl-BB. The Hsp70-expression was time- and dose-dependent, reaching a maximum after 24 h incubation with 80 microM Cd. Upon heat-stress, a similar response was observed: a strong Hsp70-expression in Hl-H4, and only a marginal one in Hl-BB. The strains reacted to Cd-exposure by a specific, environmentally related induction of MTLPs, as shown by the highly sensitive bimane derivatisation method of SH-rich proteins. In Hl-H4, a strong expression of 11 kDa MTLP was registered, which followed strictly the induction pattern of Hsp70. This suggests interdependence of the induction mechanisms and roles of these stress proteins in metal resistance. On the contrary, in Hl-BB a weak expression of MTLP of about 20 kDa was observed, exhibiting completely different induction pattern. The results suggest that the specific induction of Hsp70 and/or distinct MTLPs in the range of 11 kDa in H. lugdunensis strain Hl-H4 are essential adaptive mechanisms to continuous heavy metal exposure.

Utilization of various carbon sources for the growth of waterborne conidial fungi

Four isolates of waterborne conidial fungi (Tetracheatum elegans, Tetracladium marchalianum, Pestalotiopsis submersus and Flagellospora penicillioides) were investigated for their carbon requirement, using eight different carbon sources (viz. glucose, fructose, sucrose, xylose, starch, cellulose, dextrin and lactose). All fungi tested grew sparsely on the basal medium lacking in carbon, which was the control. However these fungi were found to vary in their ability to use the supplied sources of carbon. Glucose and sucrose were found to be suitable sources of carbon for all four fungal isolates, whereas fructose proved good for T. marchalianum and P. submersus. Starch and xylose also supported growth of T. marchalianum, P. submersus and F. penicillioides. Cellulose, a polysaccharide, was a poor source of carbon for the growth of these isolates. Four g/L of glucose was recorded as the most useful concentration that gives the maximum dry weight of selected fungi (262 mg and 400 mg for T. elegans and P. submersus respectively after 15 d).

The growth of proteolytic microorganisms affects keratinolytic fungi in sewage sludge

The present study was to demonstrate the effect of proteolytic microorganisms on the growth and composition of keratinolytic fungi in sewage sludge. In model experiments, the 3-layer hair baiting method (layer I--sludge solidified with agar medium; layer II--agar medium layer covering layer I; and layer III--hair) was used. The agar medium contained increasing peptone concentrations (0, 0.5, 1, 2, 5 and 10 g/L). The number of occurrences along with other fungal growth indices increased up to the peptone concentration of 2 g/L. Upon the highest peptone concentration (10 g/L), the abundant growth of sludge proteolytic bacteria and fungi inhibited the growth of most keratinolytic fungi. Under these conditions, only Scopulariopsis brevicaulis, the fungus of epidemiological concern, was able to penetrate the medium and to attack hair. The antibiotics (chloramphenicol and actidione in concentrations of 100 and 500 mg/L) added to the peptone agar inhibited, to a high degree, the growth of sludge proteolytic microbiota and enabled many keratinolytic fungi to grow.

Epicoccarines A, B and epipyridone: tetramic acids and pyridone alkaloids from an Epicoccum sp. associated with the tree fungus Pholiota squarrosa

Investigation of the metabolic profile of a fungus (Epicoccum sp.) isolated from the fruiting body of the tree fungus Pholiota squarrosa led to the discovery of two novel tetramic acid derivatives, epicoccarine A (2) and B (3), as well as a new pyridone alkaloid, epipyridone (1), with an unusually cyclized side chain. It appears that 1 is biogenetically derived from the ring expansion of 2 followed by a proposed hetero-Diels-Alder reaction. 2 shows selective antibacterial activity against Gram positive bacteria, in particular Mycobacterium vaccae.

The biochemistry of oleate induction: Transcriptional upregulation and peroxisome proliferation

Unicellular organisms such as yeast constantly monitor their environment and respond to nutritional cues. Rapid adaptation to ambient changes may include modification and degradation of proteins; alterations in mRNA stability; and differential rates of translation. However, for a more prolonged response, changes are initiated in the expression of genes involved in the utilization of energy sources whose availability constantly fluctuates. For example, in the presence of oleic acid as a sole carbon source, yeast cells induce the expression of a discrete set of enzymes for fatty acid beta-oxidation as well as proteins involved in the expansion of the peroxisomal compartment containing this process. In this review chapter, we discuss the factors regulating oleate induction in Saccharomyces cerevisiae, and we also deal with peroxisome proliferation in other organisms, briefly mentioning fatty acid-independent signals that can trigger this process.

Amorosia littoralis gen. sp. nov., a new genus and species name for the scorpinone and caffeine-producing hyphomycete from the littoral zone in The Bahamas

The new generic and species name Amorosia littoralis gen. sp. nov. is introduced for the conidial dematiaceous hyphomycete isolated from the littoral zone in The Bahamas and reported in 2001 to produce the novel aza-anthraquinone scorpinone, and also caffeine. No satisfactory generic placement was found at the time, but subsequent morphological and molecular investigations reveal that a new generic name is required. The new genus has some similarity to several fungi described in Trichocladium, but differs substantially from the type species of that genus in the form of the conidia and the lack of ornamentation. BLAST studies using the 18S and 28S rDNA gene sequences place the new genus in the Sporormiaceae. In addition to the morphological studies, an ultrastructural examination of the conspicuous porate septa of hyphae showed that they do not belong to a basidiomycete.