Dyes as fungal inhibitors: effect on colony diameter.

The effects of a wide range of concentrations of 13 dyes on the colony diameters of nine fungal strains (including members of the Deuteromycetes and Zygomycetes) were evaluated. Auramine at a concentration of 50 ppm (50 micrograms/ml), methylene blue at a concentration of 500 ppm, gentian violet at a concentration of 5 ppm, and phenol red at a concentration of 50 ppm performed as well as the commonly used dyes dichloran at a concentration of 2 ppm and rose bengal at a concentration of 50 ppm in that they allowed adequate colony development of the Deuteromycetes strains tested and controlled rapidly spreading fungi.     

Dyes as fungal inhibitors: effect on colony enumeration

The effects of three dyes on the colony enumeration of nine fungal strains (including members of the Deuteromycetes and Zygomycetes) in pure and mixed cultures were investigated. Using malt extract agar as basal and control medium, the following dyes and concentrations were assayed: auramine (25 ppm), gentian violet (5 ppm) and malachite green (1 ppm). The chemicals commonly used in commercial media dichloran (2 ppm) and rose bengal (50 ppm) were included in the study as reference mould-spreading inhibitors. Higher counts were usually obtained in the media containing dichloran, rose bengal or auramine, including the control medium in the absence of chemical when the mixed-conidium inocula did not include a spreading mould. Nevertheless in most cases no significant differences were observed between them. Malachite green (1 ppm) performed mainly as a strong inhibitor of spreading moulds, only allowing adequate colony development and recoveries of both Fusarium and Aspergillus strains tested.     

Phytoestrogens as inhibitors of fungal 17beta-hydroxysteroid dehydrogenase

Different phytoestrogens were tested as inhibitors of 17beta-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17beta-HSDcl), a member of the short-chain dehydrogenase/reductase superfamily. Phytoestrogens inhibited the oxidation of 100 microM 17beta-hydroxyestra-4-en-3-one and the reduction of 100 microM estra-4-en-3,17-dione, the best substrate pair known. The best inhibitors of oxidation, with IC(50) below 1 microM, were flavones hydroxylated at positions 3, 5 and 7: 3-hydroxyflavone, 3,7-dihydroxyflavone, 5,7-dihydroxyflavone (chrysin) and 5-hydroxyflavone, together with 5-methoxyflavone. The best inhibitors of reduction were less potent; 3-hydroxyflavone, 5-methoxyflavone, coumestrol, 3,5,7,4'-tetrahydroxyflavone (kaempferol) and 5-hydroxyflavone all had IC(50) values between 1 and 5 microM. Docking the representative inhibitors chrysin and kaempferol into the active site of 17beta-HSDcl revealed the possible binding mode, in which they are sandwiched between the nicotinamide moiety and Tyr212. The structural features of phytoestrogens, inhibitors of both oxidation and reduction catalyzed by the fungal 17beta-HSD, are similar to the reported structural features of phytoestrogen inhibitors of human 17beta-HSD types 1 and 2.     

Phytoestrogens as inhibitors of fungal 17beta-hydroxysteroid dehydrogenase

Different phytoestrogens were tested as inhibitors of 17beta-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus (17beta-HSDcl), a member of the short-chain dehydrogenase/reductase superfamily. Phytoestrogens inhibited the oxidation of 100microM 17beta-hydroxyestra-4-en-3-one and the reduction of 100microM estra-4-en-3,17-dione, the best substrate pair known. The best inhibitors of oxidation, with IC(50) below 1microM, were flavones hydroxylated at positions 3, 5 and 7: 3-hydroxyflavone, 3,7-dihydroxyflavone, 5,7-dihydroxyflavone (chrysin) and 5-hydroxyflavone, together with 5-methoxyflavone. The best inhibitors of reduction were less potent; 3-hydroxyflavone, 5-methoxyflavone, coumestrol, 3,5,7,4'-tetrahydroxyflavone (kaempferol) and 5-hydroxyflavone, all had IC(50) values between 1 and 5microM. Docking the representative inhibitors chrysin and kaempferol into the active site of 17beta-HSDcl revealed the possible binding mode, in which they are sandwiched between the nicotinamide moiety and Tyr212. The structural features of phytoestrogens, inhibitors of both oxidation and reduction catalyzed by the fungal 17beta-HSD, are similar to the reported structural features of phytoestrogen inhibitors of human 17beta-HSD types 1 and 2.     

Cyclobutane carboxamide inhibitors of fungal melanin: biosynthesis and their evaluation as fungicides

A new fungicide lead has been identified by enzyme screening of a focused combinatorial library. The lead compound 4, a potent inhibitor of scytalone dehydratase (SD), exhibits fungicidal activity upon foliar application but does not show systemic activity. The X-ray crystal structure of the enzyme-inhibitor complex and an appreciation for the relationship between physical properties and systemic activity enabled us to rapidly improve upon this initial lead. The geminal halogen-methyl group combination was found to be optimal for interaction with the bounding serine and asparagine side-chain residues. Replacement of CF3 with methyl was a key discovery, giving inhibitors with slightly diminished enzyme inhibition potency while significantly increasing systemic activity. Amides prepared from amines with 2,4-dichloro substitution on the phenyl ring gave the most potent enzyme inhibitors. Two compounds from this series showed systemic activity comparable to the commercial standard and were selected for outdoor testing in flooded plots which simulate rice paddies.     

Effect of fungal staling growth substances on colony interaction

Summary Effect of staling growth substances on the colony interaction in between some dominant rhizosphere fungi andSclerotium rolfsii Sacc. a root pathogen ofLens esculantum Moench. was examinedin vitro. Experimental findings depict that staling growth substances diffused in the agar created the change in the pattern of colony interaction. Measurement of growth inhibition of colony interaction was assessed with the help of a proposed model.     

Design and synthesis of simplified sordaricin derivatives as inhibitors of fungal protein synthesis

A reduction of the tetracyclic skeleton of sordarins and sordaricins to a cyclopentane ring bearing the pharmacophore functional groups led to new derivatives retaining part of their in vitro and whole-cell activity.     

Statistical analysis of structural and kinetic characteristics of fungal colony growth with Trichoderma viride PERS.: S.F. Gray

The mycelial colonies of Trichoderma viride were grown between two thin cellophane films for exact measurements. The results obtained testify to the fact that in a mature colony the average length of intercalary cells, the average number of intercalary cells in an internode and the average internode length are stable. At this stage of morphogenesis the mean internode length is shown to be equal to the product of the average intercalary cell length and the average number of intercalary cells in an internode. The coefficients of variation of the internode length and the number of intercalary cells in an internode are found to be equal. The length of an intercalary cell and duration of the doubling cycle of an apical cell of T. viride obey the law of Gamma distribution. According to our observations, the Gamma distribution is typical for the length and duration of the doubling cycle of any bacterial cells and cells of any multicellular organisms.     

Synthesis and evaluation of N-substituted 1,4-oxazepanyl Sordaricins as selective fungal EF-2 inhibitors

Sordaricin analogues possessing 6-methoxy-7-methyl-1,4-oxazepane moiety instead of the sugar part were synthesized and evaluated. It was found that N-substituents on the oxazepane ring had influence on biological activity. In particular, N-(2-methylpropenyl) derivative 12p exhibited potent in vitro antifungal activity. Furthermore, 12p maintained significant activity (MIC 0.25 microg/mL) against Candida albicans SANK51486 even in the presence of 20% horse serum.     

The Mycelium Blueprint: insights into the cues that shape the filamentous fungal colony

The mycelium is an organised cellular network that develops according to a functionally coherent plan. As it expands, the mycelium is capable of modulating the relative abundance of different cell types to suit the prevailing environmental conditions. This versatile pattern of multicellular development involves sophisticated environmental sensing and intercellular communication systems that have barely been recognised. This review describes an insight into our current understanding of the signalling molecules and mechanisms that take part in the ordered and timely emergence of various cell types and their biological significance. The prospects that this emerging knowledge may offer for the sustainable control of fungal colonisation or dispersal will also be considered.     

The effect of fungal species on the fluorescent lectin test.

Fungal (mold) contamination is an important indicator of low-quality raw product used in food processing operations. Fluorescent-labeled lectins, specific for chitin, have been shown to be valuable for quantitative detection of mold in raw tomatoes.In this research, the response of individual fungal species to a rapid fluorescent lectin assay was investigated. Ten of the most common mold species were grown on two types of artificial broth media, and added to blended field tomatoes. The assay was conducted on each species, and linear regressions were developed, comparing the fluorescent lectin assay score with the fungal dry weight. The assay was able to detect all molds at sensitivities required for the tomato industry, and had high linearity (r2 ranging from 0.72 to 0.99) and low variability (standard error of calibration ranging from 20 to 116 microg of fungal biomass/ml of tomato juice) for individual species grown on V-8 juice broth.     

The effect of apoptosis inhibitors on experimental autoimmune encephalomyelitis: apoptosis as a regulatory factor

The effect of apoptosis inhibitors on experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis, was investigated by intraperitoneal or intracisternal administration of apoptosis inhibitors Ac-YVAD-cmk and zVAD-fmk. After onset of the disease, these agents had no suppressive effect on EAE and resulted in impaired recovery or earlier relapse. Histological examination revealed that administration of zVAD-fmk suppressed the apoptotic death of inflammatory cells in the central nervous system (CNS) of mice with EAE. The results indicated that the apoptotic elimination of infiltrated cells in the CNS might be one of the recovery mechanisms in EAE.     

Nutritional influence on fungal colony growth and biomass distribution in response to toxic metals

This work examines nutritional influence on fungal colony growth and biomass distribution in response to toxic metals. In low-substrate solid medium, 0.1 mM Cd, Cu and Zn caused a decrease in radial expansion of both Trichoderma viride and Rhizopus arrhizus. However, as the amount of available carbon source (glucose) increased, the apparent toxicity of the metals decreased. These metals also affected the overall length of the fungal mycelium and branching patterns. In low-nutrient conditions, T. viride showed a decrease in overall mycelial length and number of branches in response to Cu, resulting in an extremely sparsely branched colony. Conversely, although Cd also reduced overall mycelial length to about one-third of the control length, the number of branches decreased only slightly which resulted in a highly branched colony with many aberrant features. Cu and Cd induced similar morphological changes in R. arrhizus. A large-scale mycelial-mapping technique showed that disruption of normal growth by Cu and Cd resulted in altered biomass distribution within the colony. When grown on metal-free low-substrate medium, T. viride showed an even distribution of biomass within the colony with some allocation to the periphery. However, Cu caused most of the biomass to be allocated to the colony periphery, while in the presence of Cd, most biomass was located at the interior of the colony. These results imply that such alterations of growth and resource allocation by Cu and Cd may influence success in locating nutrients as well as survival, and that these metals have individual and specific effects on the growing fungus.