Chromenol Derivatives as Novel Antifungal Agents: Synthesis, In Silico and In Vitro Evaluation

Herein we report the synthesis of some new 1H-1,2,4-triazole functionalized chromenols (3a-3n) via tandem reactions of 1-(alkyl/aryl)-2-(1H-1,2,4-triazole-1-yl) with salicylic aldehydes and the evaluation of their antifungal activity. In silico prediction of biological activity with computer program PASS indicate that the compounds have a high novelty compared to the known antifungal agents. We did not find any close analog among the over 580,000 pharmaceutical agents in the Cortellis Drug Discovery Intelligence database at the similarity cutoff of 70%. The evaluation of antifungal activity in vitro revealed that the highest activity was exhibited by compound 3k, followed by 3n. Their MIC values for different fungi were 22.1-184.2 and 71.3-199.8 µM, respectively. Twelve from fourteen tested compounds were more active than the reference drugs ketoconazole and bifonazole. The most sensitive fungus appeared to be Trichoderma viride, while Aspergillus fumigatus was the most resistant one. It was found that the presence of the 2-(tert-butyl)-2H-chromen-2-ol substituent on the 4th position of the triazole ring is very beneficial for antifungal activity. Molecular docking studies on C. albicans sterol 14α-demethylase (CYP51) and DNA topoisomerase IV were used to predict the mechanism of antifungal activities. According to the docking results, the inhibition of CYP51 is a putative mechanism of antifungal activity of the novel chromenol derivatives. We also showed that most active compounds have a low cytotoxicity, which allows us to consider them promising antifungal agents for the subsequent testing activity in in vivo assays.

miRNA Mediated Regulation and Interaction between Plants and Pathogens

Plants have evolved diverse molecular mechanisms that enable them to respond to a wide range of pathogens. It has become clear that microRNAs, a class of short single-stranded RNA molecules that regulate gene expression at the transcriptional or post-translational level, play a crucial role in coordinating plant-pathogen interactions. Specifically, miRNAs have been shown to be involved in the regulation of phytohormone signals, reactive oxygen species, and NBS-LRR gene expression, thereby modulating the arms race between hosts and pathogens. Adding another level of complexity, it has recently been shown that specific lncRNAs (ceRNAs) can act as decoys that interact with and modulate the activity of miRNAs. Here we review recent findings regarding the roles of miRNA in plant defense, with a focus on the regulatory modes of miRNAs and their possible applications in breeding pathogen-resistance plants including crops and trees. Special emphasis is placed on discussing the role of miRNA in the arms race between hosts and pathogens, and the interaction between disease-related miRNAs and lncRNAs.

Trichothecenes in Food and Feed, Relevance to Human and Animal Health and Methods of Detection: A Systematic Review

Trichothecene mycotoxins are sesquiterpenoid compounds primarily produced by fungi in taxonomical genera such as Fusarium, Myrothecium, Stachybotrys, Trichothecium, and others, under specific climatic conditions on a worldwide basis. Fusarium mold is a major plant pathogen and produces a number of trichothecene mycotoxins including deoxynivalenol (or vomitoxin), nivalenol, diacetoxyscirpenol, and T-2 toxin, HT-2 toxin. Monogastrics are sensitive to vomitoxin, while poultry and ruminants appear to be less sensitive to some trichothecenes through microbial metabolism of trichothecenes in the gastrointestinal tract. Trichothecene mycotoxins occur worldwide however both total concentrations and the particular mix of toxins present vary with environmental conditions. Proper agricultural practices such as avoiding late harvests, removing overwintered stubble from fields, and avoiding a corn/wheat rotation that favors Fusarium growth in residue can reduce trichothecene contamination of grains. Due to the vague nature of toxic effects attributed to low concentrations of trichothecenes, a solid link between low level exposure and a specific trichothecene is difficult to establish. Multiple factors, such as nutrition, management, and environmental conditions impact animal health and need to be evaluated with the knowledge of the mycotoxin and concentrations known to cause adverse health effects. Future research evaluating the impact of low-level exposure on livestock may clarify the potential impact on immunity. Trichothecenes are rapidly excreted from animals, and residues in edible tissues, milk, or eggs are likely negligible. In chronic exposures to trichothecenes, once the contaminated feed is removed and exposure stopped, animals generally have an excellent prognosis for recovery. This review shows the occurrence of trichothecenes in food and feed in 2011-2020 and their toxic effects and provides a summary of the discussions on the potential public health concerns specifically related to trichothecenes residues in foods associated with the exposure of farm animals to mycotoxin-contaminated feeds and impact to human health. Moreover, the article discusses the methods of their detection.

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.

Surface Dielectric Barrier Discharge plasma: a suitable measure against fungal plant pathogens

Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. The atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning Electron Microscopy suggests that the main mechanism is plasma etching due to Reactive Oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pre-treatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.

Biochars from olive mill waste have contrasting effects on plants, fungi and phytoparasitic nematodes

Olive mill waste (OMW), a byproduct from the extraction of olive oil, causes serious environmental problems for its disposal, and extensive efforts have been made to find cost-effective solutions for its management. Biochars produced from OMW were applied as soil amendment and found in many cases to successfully increase plant productivity and suppress diseases. This work aims to characterize biochars obtained by pyrolysis of OMW at 300 °C to 1000 °C using ¹³C NMR spectroscopy, LC-ESI-Q-TOF-MS and SEM (Scanning Electron Microscopy). Chemical characterization revealed that biochar composition varied according to the increase of pyrolysis temperature (PT). Thermal treated materials showed a progressive reduction of alkyl C fractions coupled to the enrichment in aromatic C products. In addition, numerous compounds present in the organic feedstock (fatty acids, phenolic compounds, triterpene acids) reduced (PT = 300 °C) or completely disappeared (PT ≥ 500 °C) in biochars as compared to untreated OMW. PT also affected surface morphology of biochars by increasing porosity and heterogeneity of pore size. The effects of biochars extracts on the growth of different organisms (two plants, one nematode and four fungal species) were also evaluated. When tested on different living organisms, biochars and OMW showed opposite effects. The root growth of Lepidium sativum and Brassica rapa, as well as the survival of the nematode Meloidogyne incognita, were inhibited by the untreated material or biochar produced at 300 °C, but toxicity decreased at higher PTs. Conversely, growth of Aspergillus, Fusarium, Rhizoctonia and Trichoderma fungi was stimulated by organic feedstock, while being inhibited by thermally treated biochars. Our findings showed a pattern of association between specific biochar chemical traits and its biological effects that, once mechanistically explained and tested in field conditions, may lead to effective applications in agriculture.

Synthesis, characterization and antifungal efficacy of chitosan derivatives with triple quaternary ammonium groups

A novel type of water soluble chitosan derivatives (TQCSPX) were synthesized including 3-aminopyridine (TQCSP1) and 3-Amino-4-methylpyridine (TQCSP2). The theoretical structures of TQCSPX were calculated by Gaussian 09 and confirmed by FT-IR, ¹H NMR, ¹³C NMR, elemental analysis and XRD. The antifungal properties of TQCSPX against Phytophthora capsici (P. capsici), Rhizoctonia solani (R. solani), Fusarium oxysporum (F. oxysporum) and Fusarium solani (F. solani) were evaluated at concentrations ranging from 0.2mg/mL to 0.8mg/mL. Antifungal results indicated that the derivatives have significantly enhanced antifungal activity after quaternized compared with the original chitosan (CS). Moreover, TQCSP1 inhibited the growth of P. capsici with inhibitory indices of 91.94% at 0.8mg/mL. The experimental results demonstrated that the increasing number of the positive charge would improve the antifungal efficiency of chitosan, which may provide a novel direction for the development of fungicides.

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.

Granulomatous Lymphadenitis and Splenitis Associated with Monocillium Indicum Infection in a Dog

This report describes severe generalized granulomatous lymphadenitis and splenitis in a 5-year-old, spayed female, Rottweiler dog with anorexia and diarrhea. There was replacement or effacement of much of the parenchyma of the lymph nodes and spleen by sheets of macrophages, multinucleated giant cells, and myriad nonpigmented fungal organisms, most of which appeared to be intracellular. These organisms were very pleomorphic, including large chlamydospore-like cells, small round yeast-like cells, and septate hyphae. A fungus identified as Monocillium indicum was isolated from lymph node tissue. To the authors' knowledge, this is the first report of infection with Monocillium in either humans or other animals.

Antimicrobial potentials and phytochemical analysis of desert cotton (A. Javanica) and flax (L. Ustitatissimum)

The present study reveals antimicrobial potentials and phytochemical analysis of A. javanica and L. ustitatissimum. Phytochemical analysis indicated that the tested plants contained a substantial amount of flavonoids, terpenoids and steroids while saponins and tannins were absent in L. ustitatissimum, however, tannins were present in A. javanica. L. ustitatissimum contained maximum total phenolic content of 166.36mg/g in methylated spirit fraction while its ethyl acetate fraction contained highest quantity of flavonoids 27.6mg/g in case of Aerva javanica. Antimicrobial potentials of the subject plants revealed that L. ustitatissimum had maximum antibacterial activity (MIC=4.33μg/ml) while A. javanica was most effective against fungal strains (MIC=2.66μg/ml).

[Solid-State and membrane-surface liquid cultures of micromycetes: specific features of their development and enzyme production (a review)]

Specific features in the development of micromycetes, typical mechanisms of their enzyme production, and conditions providing for an increase in enzyme secretion by the microscopic fungi in solid-state (on natural substrates and inert carriers) and membrane-surface liquid cultures are considered. The prospects and advantages of these fermentation methods for the production of extracellular enzymes are discussed and compared with submerged cultures.

Identification and evaluation of strain B37 of Bacillus subtilis antagonistic to sapstain fungi on poplar wood

Devaluation of poplar products by sapstain accounts for huge and unpredictable losses each year in China. We had isolated four poplar sapstain fungi, Ceratocystis adiposa Hz91, Lasiodiplodia theobromae YM0737, L. theobromae Fx46, and Fusarium sp. YM05, from five poplar varieties and 13 antagonistic bacteria from nine diverse varieties. After being experimented with agar plates, wood chips, and enzyme activities, strain B37 was identified as the best poplar sapstain biocontrol bacterium. The strain B37 was identified as Bacillus subtilis using sequences of the 16S rRNA gene, physiological biochemical, and morphological characteristics.

Isolation of a trypsin-chymotrypsin inhibitor and its functional properties

A novel trypsin inhibitor with thermal and pH stability, designated Merrtine, was isolated from Glycine max L. merr. The procedure involved ammonium sulfate precipitation, ion-exchange chromatography on CM-Sephadex C-50, and affinity chromatography on Affi-gel blue gel. The 20 N-terminal amino acid sequences were determined to be DEYSKPCCDLCMCTRRCPPQ, demonstrating high homology with the sequence of Bowman-Birk type trypsin inhibitors. The molecular mass and isoelectric point of the inhibitor were estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing to be 20.0 kD and 5.8, respectively. Trypsin could be completely inhibited by Merrtine when the molar ratio was 8.1. The inhibitory activity of Merrtine was unaffected after exposure to temperatures up to 85 °C, as well as within the pH range 2-12. Besides inhibiting trypsin-chymotrypsin, the inhibitor demonstrated additional antifungal activity against the species of Alternaria alternate, Fusarium oxysporum, Pythium aphanidermatum, Physalospora piricola, Botrytis cinerea, and Fusarium solani. We herein report not only the trypsin inhibitor's extraction and isolation for the first time, but also its physiochemical and antifungal properties.

Novel macrocyclic molecules based on 12a-N substituted 16-membered azalides and azalactams as potential antifungal agents

Novel macrocyclic molecules comprising sulfonyl and acyl moiety at the position N-12a of 16-membered azalides (6a-n) and azalactams (10a-r) scaffold were synthesized from cyclododecanone 1 as starting material via 5 steps and 4 steps, respectively. The antifungal activity of these compounds against Sclerotinia sclerotiorum, Pyricularia oryzae, Botrytis cinerea, Rhizoctonia solani and Phytophthora capsici were evaluated and found that compounds possessing α-exomethylene (6c, 6d, 6e and 6g) showed antifungal activity comparable to commercial fungicide Chlorothalonil against P. oryzae and compounds possessing p-chlorobenzoyl exhibited enhanced antifungal activity than those with other substituents against S. sclerotiorum, P. oryzae, and B. cinerea. These findings suggested that the α-exomethylene and p-chlorobenzoyl may be two potential pharmacological active groups with antifungal activities.

[Peculiarities of mortmass mycobiota formation in soft-deciduous young forests on old-tillage soils of the Chernihiv Polissya]

Thirty eight species of fungi were identified as a result of mycological analysis of 180 mortmass samples of Betulapendula Routh. and Populus tremula L. Mortmass mycobiota of B. pendula and P. tremula was represented by white, brown- and soft-rot species. Fungi of Ascomycota phylum were most numerous (24 species). Species of genera Aspergillus, Penicillium, Brachysporium, Cladosporium, Drechslera, Fusarium, Cylindrocarpon, Spadicesporium, Trichoderma in variants with middle and hard classes of wood degradation were identified among them. The Basidiomycota phylum was represented by 12 species; among them Armillariella mellea and Phellinus igniarius occurred most frequently. The most specific fungal complex decaying B. pendula and P tremula mortmass was observed under class III of its degradation.

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.

Antimicrobial and anti-inflammatory activities of leaf extract of Valeriana wallichii DC

Valeriana wallichii DC (Valerianaceae) is one of the most widely used traditional remedies for various complications associated with nervous system and digestion. No antimicrobial and anti-inflammatory studies have so far been carried out on the aerial parts of the plant. The present work was focused to evaluate the antimicrobial (antifungal and antibacterial) and anti-inflammatory properties of V. wallichii using reported methods. Chloroform fraction (VW-2) and hexane fraction (VW-3) exhibited significant activity against S. aureus and B. subtilus, respectively. The chloroform fraction (VW-2) showed significant activity against S. aureus with 0.27 mg/ml MIC, where 0.31 mg/ml MIC was deduced for VW-3 fraction against B. subtilus. VW-3 fraction was also found to be the most potent inhibitor of M. canis, showing 70% inhibition with an MIC value of 0.19 mg/ml. Considerable inhibitory activity was also observed for VW-2 and water fraction (VW-6) against M. canis and A. flavus. A remarkable anti-inflammatory like activity was observed for the crude extract at a dose of 200 mg/kg at all observed durations. Other doses of the sample also showed excellent activity. Looking to these results it may be concluded that V. wallichii may be a potential source for activity guided isolation of natural products with antimicrobial and anti-inflammatory-like properties.

[Results of salad machine experiment within the MARS-500 project]

The salad machine experiment was aimed to fulfill performance testing of a prototype of space conveyor-type cylindrical greenhouse PHYTOCYCLE-SL, to study growth and development of plants, and to evaluate microbial contamination of equipment in the closed manned environment. Crops of leaf cabbage Brassica chinensis L., cultivar Vesnianka were raised in the time interval between MARS-500 days 417 and 515. The greenhouse proved it serviceability demanding 17 min/(man x d) in the normal mode. Most likely that the slow growth rate and deviations in plant morphology were caused by the presence of volatile pollutants in the greenhouse compartment Accumulation of micromycetes was observed at the sites of humid surfaces contact with ambient air; reduction of the artificial soil area contacting with air decreased population of micromycetes in 40 times. Cabbage leafs were free of pathogenic microflora. These results of the experiment helped develop recommendations on how to work out some units and systems in projectable greenhouse VITACYCLE-T

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.

Reproduction of aquatic hyphomycetes at low concentrations of Ca2+, Zn2+, Cu2+, and Cd2+

Maple leaf disks were conditioned in a stream for three weeks and then aerated for 2 d in distilled water to induce fungal sporulation. The release of aquatic hyphomycete spores increased when the water was supplemented with low concentrations of Ca(2+) (5 µg/L), Zn(2+) (2.5 µg/L), Cu(2+) (0.5 µg/L), or Cd(2+) (0.125 µg/L). Higher supplement concentrations inhibited sporulation. Over the concentration range used, the sporulation response was generally best described by a quadratic regression, suggesting a biphasic or hormetic response. A similar pattern was found with the number of fungal species as the dependent variable. Anguillospora filiformis and Anguillospora longissima were generally least inhibited by metal supplements, and Ca(2+) was the least and Cd(2+) the most toxic metal. Combinations of metals had a more severe effect on fungal sporulation than predicted from addition of the effects of the metals in isolation. The biological significance of the hormetic response is unclear; however, acknowledging it is clearly relevant for establishing guidelines or recommendations in toxicology.

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.

Antibacterial and antifungal efficacy of fatty acid methyl esters from the leaves of Sesuvium portulacastrum L

OBJECTIVES

The fatty acid methyl esters (FAME extract) from Sesuvium (S.) portulacastrum was studied for its fatty acid composition and antimicrobial activity against human pathogenic microorganisms.

MATERIALS AND METHODS AND RESULTS

The gas chromatographic analysis of FAME extract revealed the presence of palmitic acid with the highest relative percentage (31.18%), followed by oleic acid (21.15%), linolenic acid (14.18%) linoleic acid (10.63%), myristic acid (6.91%) and behenic acid (2.42%). The saturated fatty acids were higher than the unsaturated fatty acids. FAME extract showed the highest antibacterial and anticandidal activities and moderate antifungal activity against the tested microorganisms. The highest mean zone of inhibition (16.3 mm) and the lowest MIC (0.25 mg/ml) and MBC (0.5 mg/ml) values were recorded against Bacillus subtilis. The lowest mean zone of inhibition (8.8 mm) and the highest MIC (8 mg/ml) and MFC (16 mg/ml) values were recorded against Aspergillus fumigatus and Aspergillus niger.

CONCLUSIONS

The results of the present study justify the use of S. portulacastrum in traditional medicine and the FAME extract can be used as a potential antimicrobial agent against the tested human pathogenic microorganisms.

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.

Synthesis of new 1,3-oxazolyl-7-chloroquinazolin-4(3H)ones and evaluation of their antimicrobial activities

2-[2-(2,6-Dichlorophenyl)amino]phenylmethyl-3-{4-[(substituted phenyl)amino]-1,3-oxazol-2-yl)-7-chloroquinazolin-4(3H)ones 5a-o have been prepared from 2-[(2,6-dichloro phenyl)amino]phenyl acetic acid 1, which was converted to acid chloride 2 and cyclized with anthranilic acid afforded benzoxazin-4(H)ones 3. Further reaction with urea gave carboxamide-7-chloroquinazolin-4(3H)ones 4 cyclized with substituted phenyl acetamide a-o. All the compounds have been confirmed by elemental analysis, IR, NMR spectral data and evaluated for antimicrobial activity. Compounds 5o, 5k, and 5m (R = 1-H, 2,5-(Cl), and 2-Cl, 4-NO2) showed good activity, compared with the standard drugs.

Synthesis and anti-microbial evaluation of some novel 1,2,4-triazole derivatives

Triazoles with different substituent groups are found to possess diverse applications in the field of medicine and industry. A series of 4-(substituted ethanoyl)amino-3-mercapto-5-(4-nitro)phenyl-1,2,4-triazoles (NU-1 to NU-15) were synthesized as novel antimicrobial agents starting from 4-nitrobenzoic acid. The chemical structures of these newly synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, FAB+ -MS spectral data and elemental analysis. Their antimicrobial activities against Staphylococcus aureus (ATCC-25923), Pseudomonas aeruginosa (ATCC-27853), Escherichia coli (ATCC-8739), Bacillus substilis (ATCC-6633), Candida albicans (MTCC-227), Aspergillus niger (MTCC-3323) and Fusarium oxysporum (MTCC-2087) were investigated.

Synthesis and in vitro antimicrobial evaluation of condensed heterocyclic 6-substituted 1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole and 1,3,4-oxadiazole derivatives of isoniazid

A series of 6-substituted-1,2,4-triazolo-[3,4-b]-1,3,4-thiadiazole (3a-g) and 1,3,4-oxadiazole (4a-g, 5) derivatives of isoniazid were synthesized in satisfactory yield and pharmacologically evaluated for their in vitro antimicrobial activity. All the synthesized compounds were in good agreement with elemental and spectral data. A majority of the tested compounds showed good to moderate antimicrobial activity against all tested pathogenic bacterial and fungal strains.

Synthesis and antibacterial properties of pyrimidine derivatives

The paper presents the synthesis of 1,2,3,7-tetraaryl-1,2,3,4-tetrahydropyrimido[4,5-d]pyrimidines. The structures of the obtained compounds were confirmed by crystallographic and spectroscopic analyses, and their antibacterial activity was tested on 9 selected strains, comparing chemical structure changes with increased microbiological activity. It was confirmed that aromatic residues in the hydrogenated pyrimidine ring constitute a significant element influencing antibacterial activity. Electronegative radicals increase microbiological activity, but decrease solubility of the compounds. Therefore, substituents should be selected in a manner ensuring a balanced effect. The presented crystal structure of 6f includes two stereoisomers, which we decided to isolate and compare the microbiological properties in further studies.

[Influence of light of different spectral composition on growth characteristics of microscopic fungi]

The features of radial growth of three microscopic fungi species were investigated at illumination by yellow, blue, green and red light. The studied species of fungi differed by isolation site (some of them were isolated from the places of high radioactive pollution, others--from the places with background level of radioactivity) and pigmentation degree (melanin-containing and light-colored). The parameters of radial growth, which are the integral indexes of the fungal organism physiology state were investigated: radial growth rate, branching degree and summarizing index--the intensity of substrate consumption. It was shown that the melanin-containing fungi Cladosporium cladosporioides growth was twice more rapid in response to blue and yellow light. Whereas such light depressed growth of non-pigmented strain of the same species as compared to control. A light response of other pigment-containing species Hormoconis resinae was far less expressed, and the light-colored species Paecilomyces lilacinus had no response to any offered conditions of illumination.

[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.

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.

Synthesis and in vitro antimicrobial study of Schiff base and thiazolidinone of 1-cyclopropyl-6-fluoro-7-[4-(2,3-dichlorophenyl)piperazin-1-yl]-4-quinolone

The title compounds, 2-substituted phenyl-3-{1-cyclopropyl-6-fluoro-7-[4-(2,3-dichlorophenylpiperazin-1-yl]-4-oxo-1,4-dihydroquinoline} carboxamido-1,3-thiazolidin-4-ones 6a-j, have been synthesized after several structural variations viz. hydrazide 2 via acid chloride, Schiff base formation and cyclization of Schiff base followed by condensation with N-(2,3-dichlorophenyl)piperazine from the lead molecule 7-chloro-1-cyclopropyl-6-fluoro-4-oxo-1,4-dihydroquinolin-3-carboxylic acid 1. The synthesized compounds were tested for their antibacterial and antifungal activity (MIC) in vitro against organisms viz. S. aureus, S. pyogenes, E. coli, P. aeruginosa, C. albicans, A. niger and A. clavatus taking gentamycin, ampicillin, chloramphenicol, ciprofloxacin, norfloxacin, nystatin and greseofulvin as standard drugs. Compounds 4i, 5i and 6j (2-Cl, 2-Cl and 4-Cl) demonstrated excellent activity compared with ampicillin.

Microwave assisted synthesis of some novel 2-pyrazoline derivatives as possible antimicrobial agents

Some new [3-(4-phenyl)-5-phenyl-4,5-dihydropyrazol-1-yl](pyridine-4-yl)methanones and 3-substituted phenyl-5-substituted phenyl-4,5-dihydro-pyrazole-1-carbothioamides have been synthesized employing microwave techniques and evaluated for antimicrobial activity. Substituted acetophenones (1) were reacted with appropriately substituted benzaldehydes (2) in the presence of ethanol to furnish substituted chalcones (3a-f). These chalcones were further treated with isonicotinic acid hydrazide (INH) to afford substituted [3-(4-phenyl)-5-phenyl-4,5-dihydropyrazol-1-yl](pyridine-4-yl)methanones (4a-f). Reaction of these chalcones with thiosemicarbazide yielded substituted 3,5-diphenyl-4,5-dihydro-1H-pyrazole-1-carbothioamides (5a-f). The structures of newly synthesized compounds (4a-f) and (5a-f) have been confirmed by suitable spectroscopic techniques such as IR and 1H NMR. All the compounds were screened for their antibacterial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa and for antifungal activity against Candida albicans and Aspergillus niger The compounds exhibited moderate antibacterial and good antifungal activities. Compound 4b and 4d showed significant antifungal activity against A. niger and C. albicans, respectively.

Endoglucanase-producing micromycetes capable of plant wastes degrading

The screening study of endoglucanase producers among 58 strains 28 species 12 genera of mesophilous and thermotolerant micromycetes has been performed. Approximately 20% of investigated strains of micromycetes showed the highest endoglucanase activities (hydrolysis rates reached 0.40-0.57) during their submerged cultivation with different cellulose-containing subsrates. Such plant wastes as rye straw, wheat bran, husk of sunflower seeds, leaves and stems of Zostera marina were optimal for fungal growth and high yields of endoglucanase. As a result, 15 strains of mesophilous and thermotolerant micromycetes with high endoglucanase activity were selected among fungi of Aspergillus, Fusarium, Penicillium and Corynascus genera.

Biological screening of Euphorbia helioscopia L

The present research is preliminary biological screening of Euphorbia helioscopia L. (Euphorbiaceae). Dichloromethane and methanol extracts of the aerial parts of the plant were investigated for their antioxidant, antifungal, antibacterial and phytotoxic activities. Dichloromethane extract exhibited significant activity against Fusarium solani with 90% Inhibition, where as the same extract also showed non-significant activity against Salmonella typhi and Bacillus subtilis. Methanolic extract has promising radical-scavenging activity in this assay. Both the extracts have non-significant phytotoxicity against lemna minor.

Growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia in Uyo, Nigeria

Mycological research was conducted on the mycelial growth, keratinolytic proteinase activity and thermotolerance ofdermatophytes associated with alopecia patients in Uyo, Nigeria. The results revealed that Microsporum sp. - AP1, Epidermophyton sp. - AP2, Trichophyton rubrum - AP4, Trichophyton mentagrophytes - AP5 and a yeast Candida albicans - AP3 isolated exhibited variable growth and keratinase activity at different temperatures. Microsporum sp. - AP1 and T. mentagrophytes - AP5 survived heat treatment at 90 degrees C but exhibited best mycelial growth at 30 degrees C (with 53.41 mg/50 ml biomass dry weight) and 40 degrees C (with 61.32 mg/50 ml biomass dry weight) respectively, after incubation for 2 weeks. Trichophyton rubrum - AP4 and Epidermophyton sp. - AP2 could not survive heat treatment at 90 degrees C but grew better at 40 degrees C (with 38.52 mg/50 ml biomass dry weight) and 30 degrees C (with 48.32 mg/50 ml biomass dry weight) respectively, over the same incubation period, while C. albicans - AP3 grew better at 30 degrees C with 38.7 mg/50 ml biomass dry weight after 2 weeks, but failed to survive at 70 degrees C. All the isolates except Candida albicans - AP3 survived at 80 degrees C and exhibited great potential to elaborate keratinolytic enzymes, with T. mentagrophytes demonstrating the best potential at 30 degrees C and 40 degrees C. Higher temperatures tended to reduce keratinolytic activities and there were significant (P < 0.05) relationships between biomass weight and enzyme productivities of all the isolates except T. mentagrophytes. This indicates that in some dermatophytes keratinolytic proteinase activity is not a function of cell multiplicity. This plus the high thermostability of the enzymes are important attributes in the consideration of preventive and therapeutic methods against dermatophytes in the tropics.

Enabling mycelial application of Hirsutella thompsonii for managing the coconut mite

Laboratory and field studies were conducted to examine the prospect of mycelial application of Hirsutella thompsonii as an alternative to the use of mycelial-conidial formulations of the fungus in the suppression of the coconut mite, Aceria guerreronis. In a series of laboratory experiments, glycerol, yeast extract powder and dehydrated malt extract broth were found to be the best among nine substances investigated as possible adjuvants for use on coconut palms in the field along with H. thompsonii mycelia. H. thompsonii biomass in the presence of adjuvants not only produced more colonies but also yielded more conidia per pellet. In terms of the density of conidia generated on a mycelial mat the treatments varied highly significantly in two methods, with glycerol showing an average of 106% increase over control. Though irradiance with simulated sunlight resulted in reduced conidiogenesis, in general, adjuvant-treated pellets, both exposed and unexposed to simulated sunlight, produced substantial conidiation compared with control, irrespective of the two incubation conditions. Better conidiation was observed under alternating light-dark regime than under total darkness in all the treatments. Glycerol boosted the pathogenicity of H. thompsonii by 16.5% over control. In the field, a newly developed mycelial formulation of H. thompsonii applied after tank-mixing separately with the three selected adjuvants brought down the post-treatment population of the coconut mite by 85.6-97.1%. Application of the fungus in combination with glycerol resulted in a tolerable mean nut damage grade of 2.0 during the pre-harvest stage, compared with an acute score of 4.0 in control palms.

Elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown

Aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. We studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of Fagus sylvatica in six forested headwater streams (pH range, 4.3-7.1). Non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference streams. We found strong relationships between aquatic hyphomycete richness and mean Al concentration (r = -0.998, p < 0.0001) and mean pH (r = 0.962, p < 0.002), meaning that fungal diversity was severely depleted in acidified streams. By contrast, mean fungal biomass was not related to acidity. Leaf breakdown rate was drastically reduced under acidic conditions raising the issue of whether the functioning of headwater ecosystems could be impaired by a loss of aquatic hyphomycete species.

SBTX, a new toxic protein distinct from soyatoxin and other toxic soybean [Glycine max] proteins, and its inhibitory effect on Cercospora sojina growth

SBTX, a novel toxin from soybean, was purified by ammonium sulfate fractionation followed by chromatographic steps DEAE-Cellulose, CM-Sepharose and Superdex 200 HR fast-protein liquid chromatography (FPLC). Lethality of SBTX to mice (LD(50) 5.6 mg/kg) was used as parameter in the purification steps. SBTX is a 44-kDa basic glycoprotein composed of two polypeptide chains (27 and 17 kDa) linked by a disulfide bond. The N-terminal sequences of the 44 and 27kDa chains were identical (ADPTFGFTPLGLSEKANLQIMKAYD), differing from that of 17 kDa (PNPKVFFDMTIGGQSAGRIVMEEYA). SBTX contains high levels of Glx, Ala, Asx, Gly and Lys and showed maximum absorption at 280 nm, epsilon(1cm)(1%) of 6.3, and fluorescence emission in the 290-450 nm range upon excitation at 280nm. The secondary structure content was 35% alpha-helix, 13% beta-strand and beta-sheet, 27% beta-turn, 25% unordered, and 1% aromatic residues. Immunological assays showed that SBTX was related to other toxic proteins, such as soyatoxin and canatoxin, and cross-reacted weekly with soybean trypsin inhibitor and agglutinin, but it was devoid of protease-inhibitory and hemagglutinating activities. The inhibitory effect of SBTX on growth of Cercospora sojina, fungus causing frogeye leaf spot in soybeans, was observed at 50 microg/ml, concentration 112 times lesser than that found to be lethal to mice. This effect on phytopathogenic fungus is a potential attribute for the development of transgenic plants with enhanced resistance to pathogens.

Melanin as a virulence factor of Paracoccidioides brasiliensis and other dimorphic pathogenic fungi: a minireview

Melanin pigments are substances produced by a broad variety of pathogenic microorganisms, including bacteria, fungi, and helminths. Microbes predominantly produce melanin pigment via tyrosinases, laccases, catecholases, and the polyketide synthase pathway. In fungi, melanin is deposited in the cell wall and cytoplasm, and melanin particles ("ghosts") can be isolated from these fungi that have the same size and shape of the original cells. Melanin has been reported in several human pathogenic dimorphic fungi including Paracoccidioides brasiliensis, Sporothrix schenckii, Histoplasma capsulatum, Blastomyces dermatitidis, and Coccidioides posadasii. Melanization appears to contribute to virulence by reducing the susceptibility of melanized fungi to host defense mechanisms and antifungal drugs.

Survival and growth of foodborne microorganisms in processed and individually wrapped cheese slices

The objectives of the research reported here were to determine the growth, survival, or inactivation of selected microorganisms on individually wrapped processed cheese (IWC) slices stored at 5 degrees C and 22 degrees C, and to compare quality indices. IWC slices were spot-inoculated with foodborne pathogenic bacteria (Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp.), spoilage bacteria (Pseudomonas spp. and Lactobacillus spp.), and spoilage molds (Penicillium spp. and Cladosporium spp.). Each bacterium was inoculated at 10(5) CFUs/g for determination of growth, survival, or inactivation. Molds were inoculated at 10(2) spores per gram and observed for growth. Fifty percent of the inoculated product samples were held at 5 degrees C (to simulate refrigeration), and the other 50 percent were held at 22 degrees C (to simulate ambient temperature) throughout shelf life. Samples taken on days 0, 3, 7,10, 14, and 28 and after 2, 3, 6, and 9 months, and were evaluated for surviving cells (by means of appropriate selective media), color (with the cheese color guide), and lipid oxidation (by means of peroxide values). Bacterial inactivation was observed in all conditions. At 14 days, a 5-log reduction was observed for Listeria monocytogenes and Salmonella, while a 3-log reduction was observed for Staphylococcus aureus. For Pseudomonas spp. and Lactobacillus spp., a 2-log reduction was observed within 3 days, with an additional 1-log reduction noted after several months. Mold levels showed no change during the first several weeks of storage. At 84 days, mold levels decreased at 5 degrees C, but they showed growth at 22 degrees C, to approximately 10(5) CFUs/g. Visual color was evaluated on a 10-point National Cheese Institute scale. During storage at 5 degrees C or 22 degrees C, color became darker and values increased from 4 to 5 and 4 to 7, respectively. Higher peroxide values were also obtained for the samples held at 22 degrees C versus 5 degrees C. From a microbiological standpoint, pathogenic and spoilage bacteria were unable to grow in this product; however, long-term storage at 22 degrees C led to lower product quality and mold growth.

Soil mycofloral responses following the exposure to 2, 4-D

2, 4-dichlorophenoxyacetic acid (2,4-D) is a post emergence herbicide. The tests were conducted to study the toxicity of 2,4-D using EC50 value in four dilutions. 2,4-D was applied at concentration of 25, 50, 75, 100, 200 and 300 mg l(-1) in the potato Dextrose agar medium. The effect of this herbicide was evaluated as the colony forming unit (CFU). EC50 value for 10(-3) dilution of soil was 138 +/- 5.944 mg l(-1). Soil physico-chemical parameters and mycofloral properties were also evaluated. Qualitatively 10 genera of fungi were observed in untreated soil, whereas 4 genera were found in 2,4-D administered dose.

[Biosynthesis of macrocyclic trichothecenes: some aspects of physiology]

The data of long-term investigations of the control of macrocyclic trichothecenes biosynthesis by means ofthe elements of mineral nutrition, microelements in particular in Dendrodochium toxicum Pidopl. et Bilai are presented. The media for providing the dominant synthesis (50-70 %) of certain component from the composite complex of dendrodochins and so for obtaining the fractions enriched with this component, have been worked out. This method simplifies considerably the isolation of components in the crystal state. The media for obtaining verrucarin A, roridin A and roridin H are proposed.

Aquatic hyphomycete communities as potential bioindicators for assessing anthropogenic stress

With a profound knowledge of how physico-chemical parameters affect these communities, microbial communities could be used as indicators for environmental changes and for risk assessment studies. We studied aquatic hyphomycete communities in rivers and aquifers from sites shaped by intense mining activities (namely the "Mansfeld region") and chemical industry (cities of Halle and Bitterfeld) in Central Germany. Environmental stress factors such as high concentrations of heavy metals, sulphate, and nitrate as well as low concentrations of oxygen significantly reduced the diversity and biomass of hyphomycetes in the investigated samples. Redundancy analysis (RDA) indicates that variations in water chemistry cause a significant proportion of the change in fungal community structure (86.2%). Fungi were negatively correlated with high metal and nutrient concentrations. RDA also showed a strong influence of organic matter on individual species, with Anguillospora longissima (Sacc. et Syd.), Clavatospora longibrachiata (Ingold), Clavariopsis aquatica (De Wild), Flagellospora curvula (Ingold), Heliscus lugdunensis (Sacc. et Thérry), Tumularia aquatica (Ingold) and Lemonniera aquatica (De Wild) being most sensitive. We propose that aquatic hyphomycete communities can be used as sensitive and integrative indicators for freshwater quality.

Biological control of corky root in tomato

Corky root caused by Pyrenochaeta lycopersici (Schneider et Gerlach) is one of the most important soil borne fungal pathogens which develops in the soils, causing diseases in different crops. The research was carried out to evaluate the effectiveness of the biological control of corky root on tomato. Biological control was performed by using Trichoderma viride Pers. 18/17 SS, Streptomyces spp. AtB42 and Bacillus subtilis M51 PI. According to present and future regulations on the use of chemical fungicides and considering that treatments must avoids environmental pollution, the main object of this research was to find alternative strategies by using biocontrol agents against P. lycopersici that affect tomato plants. In laboratory, the effectiveness of T. viride 18/17 SS, Streptomyces spp. AtB42 and B. subtilis M51 PI to control P. lycopersici were studied. In greenhouse, the research was carried out comparing the following treatments: 1) untreated control; 2) T. viride 18/17 SS; 3) Streptomyces spp. AtB42; 4) B. subtilis M51 PI. Roots of plants of tomato H3028 Hazera were treated with the antagonist suspensions just prior of transplant. Treatments were repeated about 2 months after, with the same suspensions sprayed on the soil to the plant collar. In dual culture, the inhibition of P. lycopersici ranged up to 81.2% (caused from T. viride 18/17 SS), 75.6% (from Streptomyces spp. AtB42) and 66.8% (from B. subtilis M51 PI). In greenhouse trials, with regard to corky root symptoms, all treated plots showed signifycative differences compared to untreated. T. viride gave the better results followed by Streptomyces spp. and then by B. subtilis. The fungus antagonist showed good root surface competence such as demonstrated its persistence on the roots surface of the tomato plants whose roots were treated with T. viride 18/17 SS up to 2 months before.

Overexpression of VvWRKY2 in tobacco enhances broad resistance to necrotrophic fungal pathogens

WRKY genes encode proteins belonging to a large family of transcription factors that are involved in various developmental and physiological processes and in plant responses to pathogen infections. In the present work, a full-length cDNA from a Vitis vinifera L. cv. Cabernet Sauvignon grape berry library was isolated and characterized. The cDNA, designated VvWRKY2, encodes a polypeptide of 536 amino acids that shows the structural features of group I of WRKY protein family. VvWRKY2 is expressed in the different organs of healthy grapevine plants. In leaves, VvWRKY2 is induced by wounding and after infection with Plasmopara viticola. Constitutive expression of VvWRKY2 in tobacco reduced the susceptibility of transgenic tobacco to three types of fungal pathogens infecting different parts of the plant: Botrytis cinerea (leaves), Pythium spp. (roots) and Alternaria tenuis (seeds). The results indicate that VvWRKY2 may be involved in the resistance of grapevine against the pathogens.

Bacterial and fungal deterioration of the Milan Cathedral marble treated with protective synthetic resins

Surfaces are continuously exposed to physical, chemical and biological degradation. Among the biological agents that cause deterioration, microorganisms are of critical importance. This work is part of a research programme for the characterisation of the alterations of the Milan Cathedral (Italy). Four stone samples of the Milan Cathedral were chemically analysed and the microbiological growth assessed. X-ray diffraction (XRD) showed that calcite was always present in each sample and one sample was also characterised by the chemical form of alteration gypsum. Using Fourier Transform Infrared Spectroscopy (FTIR) together with Scanning Electron Microscopy (SEM), it was possible to prove that the samples were consolidated with the synthetic acrylics and epoxy resins. The green-black biological patinas of the specimens were studied using cultivation, microscope observations and a method for single-cell detection. Sampling for fluorescent in-situ hybridisation (FISH), with ribosomal RNA targeted oligonucleotide probes, was also performed using adhesive tapes. The bulk of the prokaryotes were Bacteria but some Archaea were also found. The bacterial cells were further characterised using specific probes for Cyanobacteria, and alpha-, beta-and gamma-Proteobacteria. In addition, black fungi isolated from the stone and the fungi of the standard ASTM G21-96(2002) method were employed to test if the detected synthetic resins could be used as the sole source of carbon and energy. One isolated Cladosporium sp. attacked the freshly dried acrylic resin. Results show that the detected bacteria and fungi can cause severe damage both to the stone monument and its synthetic consolidants.

Fungal thigmotropism in onychomycosis and in a clear hydrogel pad model

BACKGROUND

Thigmotropism is a biological characteristic corresponding to the directional growth of cells following topographical guidance cues. This behavior has been shown experimentally with fungal hyphae of both dermatophytes and nondermatophyte molds, as well as with the mycelial phase of the dimorphic yeast Candida albicans.

OBJECTIVE AND METHODS

We presently document this phenomenon using histomycology in onychomycoses of various fungal origins.

RESULTS

This mechanism is involved in the invasive phase of the pathogen or opportunistic fungi, and it probably governs various clinical aspects of onychomycoses. We incidentally disclosed fungal invasions of hydrogel pads.

CONCLUSION

Thigmotropism can in part explain the diversity of orientations and shapes of fungi invading nail plates. The same phenomenon was disclosed inside hydrogel pads. As this material is transparent and easy to cut for microscopic examination, fungal thigmotropism is conveniently explored by this way.