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Filamentous Fungi (filamentous + fungus)
Terms modified by Filamentous Fungi Selected Abstracts104th Event of the European Federation of Biotechnology "Physiology of Yeasts and Filamentous Fungi"FEMS YEAST RESEARCH, Issue 3 2001Jack T Pronk No abstract is available for this article. [source] Histone modifications and chromatin dynamics: a focus on filamentous fungiFEMS MICROBIOLOGY REVIEWS, Issue 3 2008Gerald Brosch Abstract The readout of the genetic information of eukaryotic organisms is significantly regulated by modifications of DNA and chromatin proteins. Chromatin alterations induce genome-wide and local changes in gene expression and affect a variety of processes in response to internal and external signals during growth, differentiation, development, in metabolic processes, diseases, and abiotic and biotic stresses. This review aims at summarizing the roles of histone H1 and the acetylation and methylation of histones in filamentous fungi and links this knowledge to the huge body of data from other systems. Filamentous fungi show a wide range of morphologies and have developed a complex network of genes that enables them to use a great variety of substrates. This fact, together with the possibility of simple and quick genetic manipulation, highlights these organisms as model systems for the investigation of gene regulation. However, little is still known about regulation at the chromatin level in filamentous fungi. Understanding the role of chromatin in transcriptional regulation would be of utmost importance with respect to the impact of filamentous fungi in human diseases and agriculture. The synthesis of compounds (antibiotics, immunosuppressants, toxins, and compounds with adverse effects) is also likely to be regulated at the chromatin level. [source] Characterization of an acyl-CoA: carboxylate CoA-transferase from Aspergillus nidulans involved in propionyl-CoA detoxificationMOLECULAR MICROBIOLOGY, Issue 3 2008Christian B. Fleck Summary Filamentous fungi metabolize toxic propionyl-CoA via the methylcitrate cycle. Disruption of the methylcitrate synthase gene leads to an accumulation of propionyl-CoA and attenuates virulence of Aspergillus fumigatus. However, addition of acetate, but not ethanol, to propionate-containing medium strongly reduces the accumulation of propionyl-CoA and restores growth of the methylcitrate synthase mutant. Therefore, the existence of a CoA-transferase was postulated, which transfers the CoASH moiety from propionyl-CoA to acetate and, thereby, detoxifying the cell. In this study, we purified the responsible protein from Aspergillus nidulans and characterized its biochemical properties. The enzyme used succinyl-, propionyl- and acetyl-CoA as CoASH donors and the corresponding acids as acceptor molecules. Although the protein displayed high sequence similarity to acetyl-CoA hydrolases this activity was hardly detectable. We additionally identified and deleted the coding DNA sequence of the CoA-transferase. The mutant displayed weak phenotypes in the presence of propionate and behaved like the wild type when no propionate was present. However, when a double-deletion mutant defective in both methylcitrate synthase and CoA-transferase was constructed, the resulting strain was unable to grow on media containing acetate and propionate as sole carbon sources, which confirmed the in vivo activity of the CoA-transferase. [source] Looking through the eyes of fungi: molecular genetics of photoreceptionMOLECULAR MICROBIOLOGY, Issue 1 2007Alfredo Herrera-Estrella Summary Filamentous fungi respond to a variety of environmental signals. One of them is light, providing critical information about orientation, or impending stress. Cells of filamentous fungi appear to sense blue light through a unique transcription factor that has a flavin chromophore and activates its targets in a light-dependent manner, the white collar (WC) complex. Fungal photophysiology, though, predicted a greater complexity of responses to the whole visible spectrum. The rapidly growing fungal genome database provides candidates to explain how fungi see not only blue, but also near-UV, green and red light. At the same time, there are surprises in the genomes, including photoreceptors for which there are no obvious photoresponses. Linking these genes and their functions will help understand how a list of only a few biological chromophores accounts for such a diversity of responses. At the same time, deeper mechanistic understanding of how the WC complex functions will lead to fundamental insights at the point where the environment impinges, in this case in the form of photons, on the transcriptional machinery of the cell. [source] Deletion of mdmB impairs mitochondrial distribution and morphology in Aspergillus nidulansCYTOSKELETON, Issue 2 2003Katrin V. Koch Abstract Mitochondria form a dynamic network of interconnected tubes in the cells of Saccharomyces cerevisiae or filamentous fungi such as Aspergillus nidulans,Neurospora crassa, or Podospora anserina. The dynamics depends on the separation of mitochondrial fragments, their movement throughout the cell, and their subsequent fusion with the other parts of the organelle. Interestingly, the microtubule network is required for the distribution in N. crassa and S. pombe, while S. cerevisiae and A. nidulans appear to use the actin cytoskeleton. We studied a homologue of S. cerevisiae Mdm10 in A. nidulans, and named it MdmB. The open reading frame is disrupted by two introns, one of which is conserved in mdm10 of P. anserina. The MdmB protein consists of 428 amino acids with a predicted molecular mass of 46.5 kDa. MdmB shares 26% identical amino acids to Mdm10 from S. cerevisiae, 35% to N. crassa, and 32% to the P. anserina homologue. A MdmB-GFP fusion protein co-localized evenly distributed along mitochondria. Extraction of the protein was only possible after treatment with a non-ionic and an ionic detergent (1% Triton X-100; 0.5% SDS) suggesting that MdmB was tightly bound to the mitochondrial membrane fraction. Deletion of the gene in A. nidulans affected mitochondrial morphology and distribution at 20°C but not at 37°C. mdmB deletion cells contained two populations of mitochondria at lower temperature, the normal tubular network plus some giant, non-motile mitochondria. Cell Motil. Cytoskeleton 55:114,124, 2003. © 2003 Wiley-Liss, Inc. [source] Role of the two type II myosins, Myo2 and Myp2, in cytokinetic actomyosin ring formation and function in fission yeastCYTOSKELETON, Issue 3 2003Daniel P. Mulvihill Abstract The formation and contraction of a cytokinetic actomyosin ring (CAR) is essential for the execution of cytokinesis in fission yeast. Unlike most organisms in which its composition has been investigated, the fission yeast CAR contains two type II myosins encoded by the genes myo2+ and myp2+. myo2+ is an essential gene whilst myp2+ is dispensable under normal growth conditions. Myo2 is hence the major contractile protein of the CAR whilst Myp2 plays a more subtle and, as yet, incompletely documented role. Using a fission yeast strain in which the chromosomal copy of the myo2+ gene is fused to the gene encoding green fluorescent protein (GFP), we analysed CAR formation and function in the presence and absence of Myp2. No change in the rate of CAR contraction was observed when Myp2 was absent although the CAR persisted longer in the contracted state and was occasionally observed to split into two discrete rings. This was also observed in myp2, cells following actin depolymerisation with latrunculin. CAR contraction in the absence of Myp2 was completely abolished in the presence of elevated levels of chloride ions. Thus, Myp2 appears to contribute to the stability of the CAR, in particular at a late stage of CAR contraction, and to be a component of the signalling pathway that regulates cytokinesis in response to elevated levels of chloride. To determine whether the presence of two type II myosins was a feature of cytokinesis in other fungi that divide by septation, we searched the genomes of two filamentous fungi, Aspergillus fumigatus and Neurospora crassa, for myosin genes. As in fission yeast, both A. fumigatus and N. crassa contained myosins of classes I, II, and V. Unlike fission yeast, both contained a single type II myosin gene that, on the basis of its tail structure, was more reminiscent of Myp2 than Myo2. The significance of these observations to our understanding of septum to formation and cleavage is discussed. Cell Motil. Cytoskeleton 54:208,216, 2003. © 2003 Wiley-Liss, Inc. [source] Characterization of the surface hydrophobicity of filamentous fungiENVIRONMENTAL MICROBIOLOGY, Issue 2 2003Theo H. M. Smits Summary A method for the quantitative analysis of the hydrophobicity of the mycelial mat of filamentous fungi based on contact angle measurements is presented. It was tested for a range of fungi belonging to the classes of basidiomycetes, ascomycetes and deuteromycetes. The measured contact angles of the mycelial mats ranged between hydrophilic (<30°) for the deuteromycetes Fusarium oxysporum Fo47 GUS1 and Trichoderma harzianum P1[pZEGA1] and hydrophobic (>60°) for the ascomycete Cladosporium sp. DSE48.1b and the basidiomycetes Paxillus involutus WSL 37.7, Hebeloma crustiliniforme WSL 6.2, Suillus bovinus WSL 48.1 and Laccaria bicolor WSL 73.1. For some fungi, variations in the hydrophobicity of the mycelium depending on the growth medium, the physiological state and the exposure to water were distinguished. [source] Cloning and sequence analysis of cnaA gene encoding the catalytic subunit of calcineurin from Aspergillus oryzaeFEMS MICROBIOLOGY LETTERS, Issue 1 2001Praveen Rao Juvvadi Abstract Calcineurin has been implicated in ion-homeostasis, stress adaptation in yeast and for hyphal growth in filamentous fungi. Genomic DNA and cDNA encoding the catalytic subunit of calcineurin (cnaA) were isolated from Aspergillus oryzae. The cnaA open reading frame extended to 1727 bp and encoded a putative protein of 514 amino acids. Comparative analysis of the nucleotide sequence of cnaA genomic DNA and cDNA confirmed the presence of three introns and a highly conserved calmodulin binding domain. The deduced amino acid sequence was homologous to calcineurin A from Aspergillus nidulans (92%), Neurospora crassa (84%), human (67%), Saccharomyces cerevisiae (58%) and Schizosaccharomyces pombe (54%). Further, A. oryzae cnaA cDNA complemented S. cerevisiae calcineurin disruptant strain (,cmp1,cmp2), which was not viable in the presence of high concentrations of NaCl (1.2 M) and at alkaline pH 8.5. [source] Histone modifications and chromatin dynamics: a focus on filamentous fungiFEMS MICROBIOLOGY REVIEWS, Issue 3 2008Gerald Brosch Abstract The readout of the genetic information of eukaryotic organisms is significantly regulated by modifications of DNA and chromatin proteins. Chromatin alterations induce genome-wide and local changes in gene expression and affect a variety of processes in response to internal and external signals during growth, differentiation, development, in metabolic processes, diseases, and abiotic and biotic stresses. This review aims at summarizing the roles of histone H1 and the acetylation and methylation of histones in filamentous fungi and links this knowledge to the huge body of data from other systems. Filamentous fungi show a wide range of morphologies and have developed a complex network of genes that enables them to use a great variety of substrates. This fact, together with the possibility of simple and quick genetic manipulation, highlights these organisms as model systems for the investigation of gene regulation. However, little is still known about regulation at the chromatin level in filamentous fungi. Understanding the role of chromatin in transcriptional regulation would be of utmost importance with respect to the impact of filamentous fungi in human diseases and agriculture. The synthesis of compounds (antibiotics, immunosuppressants, toxins, and compounds with adverse effects) is also likely to be regulated at the chromatin level. [source] Hydrophobins: the protein-amphiphiles of filamentous fungiFEMS MICROBIOLOGY REVIEWS, Issue 5 2005Markus B. Linder Abstract Hydrophobins are surface active proteins produced by filamentous fungi. They have a role in fungal growth as structural components and in the interaction of fungi with their environment. They have, for example, been found to be important for aerial growth, and for the attachment of fungi to solid supports. Hydrophobins also render fungal structures, such as spores, hydrophobic. The biophysical properties of the isolated proteins are remarkable, such as strong adhesion, high surface activity and the formation of various self-assembled structures. The first high resolution three dimensional structure of a hydrophobin, HFBII from Trichoderma reesei, was recently solved. In this review, the properties of hydrophobins are analyzed in light of these new data. Various application possibilities are also discussed. [source] Evolution and phylogenetic relationships of APSES proteins from HemiascomycetesFEMS YEAST RESEARCH, Issue 4 2008Bernardo Ramírez-Zavala Abstract Available complete genomic sequences of hemiascomycetous yeast species were analysed in order to identify the APSES protein family, which belongs to transcriptional factors of the basic helix,loop,helix (bHLH) class. Phylogenetic analyses of the amino acid sequences revealed that a similar set of proteins were present in all yeast species studied. The genome duplication event of Saccharomycetales allows the acquisition of complementary functions between the APSES proteins. Putative ancestors, such as Ashbya gossypii, the Kluyveromyces group and filamentous fungi, only have one APSES protein. Conserved gene order relationships allow the possibility of tracing the evolution of this family and the detection of duplication events. Multiple alignments revealed strict conservation of the APSES motif, although other regions of the APSES proteins were diversified. This review focuses on the evolution of the gene family of APSES proteins in related Hemiascomycetes species; the comparisons could shed light on the functional overlap of these proteins with regard to the regulation of morphogenetic processes and their involvement in the virulence of pathogenic microorganisms. [source] Enhancement of antibiotic and secondary metabolite detection from filamentous fungi by growth on nutritional arraysJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2008G.F. Bills Abstract Aims:, We asked to what extent does the application of the OSMAC (one strain, many compounds) approach lead to enhanced detection of antibiotics and secondary metabolites in fungi? Protocols for bacterial microfermentations were adapted to grow fungi in nutritional arrays. Methods and Results:, Protocols for microfermentations of non-sporulating fungi were validated using known antifungal-producing fungi. Detection of antifungal activity was often medium dependent. The effects of medium arrays and numbers of strains on detection of antifungal signals were modelled by interpolation of rarefaction curves derived from matrices of positive and negative extracts. Increasing the number of fermentation media for any given strain increased the probability of detection of growth inhibition of Candida albicans. Increasing biodiversity increased detection of antifungal phenotypes, however, nutritional arrays could partly compensate for lost antibiotic phenotypes when biodiversity was limiting. Conclusions:, Growth and extraction in microtiter plates can enable a discovery strategy emphasizing low-cost medium arrays that can better exploit the metabolic potential of strains. Significance and Impact of the Study:, Increasing fermentation parameters raise the probability of detecting bioactive metabolites from strains. The protocols can be used to pre-select strains and their growth conditions for scale up that will most likely yield antibiotics and secondary metabolites. [source] Activity and mode of action against fungal phytopathogens of bovine lactoferricin-derived peptidesJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2006A. Muñoz Abstract Aim:, To evaluate the activity against fungal phytopathogens of two synthetic peptides derived from the protein bovine lactoferricin: the antibacterial active core of six amino acid residues (LfcinB20,25) and an extension of 15 amino acids (LfcinB17,31). Methods and Results:,In vitro activity against fungal pathogens was determined and compared with that against model micro-organisms. Activity was demonstrated against fungi of agronomic relevance. Distinct antimicrobial properties in vitro were found for the two peptides. LfcinB17,31 had growth inhibitory activity higher than LfcinB20,25. However, LfcinB17,31 was not fungicidal to quiescent conidia of Penicillium digitatum at the concentrations assayed, while LfcinB20,25 killed conidia more efficiently. Microscopical observations showed that the mycelium of P. digitatum treated with LfcinB17,31 developed alterations of growth, sporulation and chitin deposition, and permeation of hyphal cells. In experimental inoculations of mandarins, both peptides showed limited protective effect against the disease caused by P. digitatum. Conclusions:, LfcinB20,25 and LfcinB17,31 peptides were shown to have antimicrobial activity against plant pathogenic filamentous fungi, with distinct properties and mode of action. Significance and Impact of the Study:, LfcinB20,25 and LfcinB17,31 peptides offer novel alternatives to develop resistant plants by molecular breeding. [source] Penicillium chrysogenum glucose oxidase , a study on its antifungal effectsJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2004É. Leiter Abstract Aims:, Purification and characterization of the high molecular mass Candida albicans -killing protein secreted by Penicillium chrysogenum. Methods and Results:, The protein was purified by a combination of ultrafiltration, chromatofocusing and gel filtration. Enzymological characteristics [relative molecular mass (Mr) = 155 000, subunit structure ,2 with Mr,, = 76 000, isoelectric point (pI) = 5·4] were determined using SDS-PAGE and 2D-electrophoresis. N-terminal amino acid sequencing and homology search demonstrated that the antifungal protein was the glucose oxidase (GOX) of the fungus. The enzyme was cytotoxic for a series of bacteria, yeasts and filamentous fungi. Vitamin C (1·0 mg ml,1) prevented oxidative cell injuries triggered by 0·004 U GOX in Emericella nidulans cultures but bovine liver catalase was ineffective even at a GOX : catalase activity ratio of 0·004 : 200 U. A secondary inhibition of growth in E. nidulans cultures by the oxygen-depleting GOX,catalase system was likely to replace the primary inhibition exerted by H2O2. Conclusions:,Penicillium chrysogenum GOX possesses similar enzymological features to those described earlier for other Penicillium GOXs. Its cytotoxicity was dependent on the inherent antioxidant potential of the test micro-organisms. Significance and Impact of the Study:,Penicillium chrysogenum GOX may find future applications in glucose biosensor production, the disinfection of medical implants or in the food industry as an antimicrobial and/or preservative agent. [source] Effects of ultrasound on culture of Aspergillus terreusJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2008Nuria Sainz Herrán Abstract BACKGROUND: Fermentations of Aspergillus terreus are commercially used to produce lovastatin. How ultrasound might influence this fermentation is unknown. While high-intensity ultrasound is effective in disrupting microbial cells, ultrasound of low intensity is known to improve productivity of some fermentation processes without damaging cells. Mechanisms behind productivity improvements have not been clearly identified in earlier studies. This work reports on the effects of ultrasound on A. terreus fermentation for low (957 W m,3), medium (2870 W m,3) and high (4783 W m,3) values of sonication power input in a slurry bubble column sonobioreactor. RESULTS: Sonication at any power level did not affect biomass growth profiles in comparison with negative controls. In contrast, medium- and high-intensity sonication greatly reduced production of lovastatin and substantially altered the growth morphology. At medium and high intensity, ultrasound disrupted fungal pellets and caused the biomass to grow mainly as dispersed hyphae. Sonication affected broth rheology because rheology depends on the morphology of the suspended biomass. CONCLUSION: Sonication can be used to modify growth morphology and broth rheology without affecting growth of filamentous fungi. Sonication appears to influence the primary growth metabolism and secondary metabolism differently in different situations. Copyright © 2008 Society of Chemical Industry [source] Biodiesel production by direct methanolysis of oleaginous microbial biomassJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 8 2007Bo Liu Abstract Biodiesel is a renewable fuel conventionally prepared by transesterification of pre-extracted vegetable oils and animal fats of all resources with methanol, catalyzed by strong acids or bases. This paper reports on a novel biodiesel production method that features acid-promoted direct methanolysis of cellular biomass of oleaginous yeasts and filamentous fungi. The process was optimized for tuning operation parameters, such as methanol dosage, catalyst concentration, reaction temperature and time. Up to 98% yield was reached with reaction conditions of 70 °C, under ambient pressure for 20 h and a dried biomass to methanol ratio 1:20 (w/v) catalyzed by either 0.2 mol L,1 H2SO4 or 0.4 mol L,1 HCl. Cetane numbers for these products were estimated to range from 56 to 59. This integrated method is thus effective and technically attractive, as dried microbial biomass as feedstocks omits otherwise tedious and time-consuming oil extraction processes. Copyright © 2007 Society of Chemical Industry [source] Organic acids: old metabolites, new themesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 10 2006Israel Goldberg Abstract Fumaric, L -malic and citric acids are intermediates of the oxidative tricarboxylic acid (TCA) cycle which in eukaryotes is localized in mitochondria. These organic acids are synthesized and accumulated in the medium to very high concentrations by filamentous fungi such as Aspergillus spp. and Rhizopus sp. This article reviews basic research on the unusual acid production capability and the associated metabolic pathways operating under defined stress conditions in these specific fungi. In particular, we describe and discuss the importance of the cytosolic reductive TCA pathway, which includes the cytosolic activities of pyruvate carboxylase, malate dehydrogenase and fumarase, for production of fumaric and L -malic acids. This article also describes the differences between fumaric acid, L -malic acid and citric acid production by different organisms (filamentous fungi, yeast, and higher eukaryotes), and the possible application of novel technologies (genetic engineering and bioinformatics) to fungal systems which may offer new industrial potential of filamentous fungi for the production of valuable metabolites. Copyright © 2006 Society of Chemical Industry [source] DIRECT PLATING: A METHOD FOR DETECTING FUNGAL CONTAMINATION IN PAPERBOARD CARTONSJOURNAL OF FOOD SAFETY, Issue 3 2001JAN A. NARCISO ABSTRACT Contamination of refrigerated juice products in gable-top cartons can occur by filamentous fungi that are present in the paperboard. A method was developed to assay the mycoflora of paperboard carton material used in beverage packaging. This method involved direct plating on an agar surface of 1 cm2 carton pieces rather than disintegration of carton material in a blender prior to plating. When compared to the standard disintegration method traditionally used for monitoring contamination of paperboard, the new method is less cumbersome, more efficient, and reduces opportunities for contamination. The number of colonies produced by the direct plating method was greater than or equal to the modified standard disintegration method. Direct plating also resulted in a larger number of different genera isolated. [source] Incidence, Aggressiveness and In Planta Interactions of Botrytis cinerea and other Filamentous Fungi Quiescent in Grape Berries and Dormant Buds in Central Washington StateJOURNAL OF PHYTOPATHOLOGY, Issue 7 2002F. M. Dugan Abstract Recovery of quiescent filamentous fungi from non-symptomatic grape berries and dormant buds demonstrated dominance of Alternaria, Aureobasidium, Cladosporium, Ulocladium and other dematiaceous hyphomycetes. Up to 78% of berries contained fungi prior to harvest. Botrytis cinerea was recovered from 0.2 to 0.5% of surface-disinfested berries just subsequent to fruit set, and 1.6,4.8% of surface-disinfested, over-wintered dormant buds. In laboratory inoculations of mature grape berries with strains of Alternaria, Aureobasidium, Cladosporium, Ulocladium and Botrytis, only the latter was aggressive in rotting berry fruits. Inoculations with B. cinerea alone and in combination with strains of Alternaria, Aureobasidium, Cladosporium and Ulocladium recovered from grape demonstrated that prior occupation of wound sites by the latter fungi resulted in reduced lesion size compared to inoculation with B. cinerea alone. [source] Characterization of glycolipid biosurfactant from Pseudomonas aeruginosa CPCL isolated from petroleum-contaminated soilLETTERS IN APPLIED MICROBIOLOGY, Issue 1 2010J. Arutchelvi Abstract Aims:, To isolate and characterize the biosurfactant-producing micro-organism from petroleum-contaminated soil as well as to determine the biochemical properties of the biosurfactant. Methods and Results:, A novel rhamnolipid-producing Pseudomonas aeruginosa (GenBank accession number GQ241355) strain was isolated from a petroleum-contaminated soil. Surface active compound was separated by solvent extraction of the acidified culture supernatant. The extract was able to reduce the surface tension of water from 72 to 44 mN m,1 at a critical micelle concentration of 11·27 ± 1·85 mg l,1. It showed better activity (based on microdilution method) against Gram-positive (, 31 mg ml,1) bacteria and filamentous fungi (, 50 mg ml,1) than Gram-negative bacteria (, 125 mg ml,1) with mild toxicity (HC50, 38 ± 8·22 ,g ml,1) to red blood cells. Fourier transform infrared spectroscopy revealed the presence of aliphatic chain, hydroxyl groups, ester and glycosidic bonds. Presence of nineteen rhamnolipid homologues with variation in chain length and saturation was revealed from liquid chromatography coupled to mass spectrometry with electrospray ionization. Conclusion:, The results indicate that the isolated biosurfactant has a novel combination of rhamnolipid congeners with unique properties. Significance and Impact of the Study:, This study provides a biosurfactant, which can be used as a biocontrol agent against phytopathogens (Fusarium proliferatum NCIM 1105 and Aspergillus niger NCIM 596) and exploited for biomedical applications. [source] An intact soil-core microcosm method to evaluate the survival and vertical dispersal of Trichoderma atroviride SC1LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009C.M.O. Longa Abstract Aim:, To develop an intact soil-core microcosm method to study the survival and vertical dispersal of an experimental biocontrol agent (Trichoderma atroviride SC1) applied to the soil surface. Methods and Results:, The soil for the microcosms was collected using iron pipes with perforations corresponding to different soil layers. The tool was inserted into the soil and gently removed with the soil core inside. Trichoderma atroviride SC1 was mixed with the top layer of soil in the pipe. The experiment was performed in 2006 and 2007, and data from the microcosms were compared with results obtained under field conditions in the locations in which, the microcosms were collected, in the same periods. The concentrations of T. atroviride SC1 in the soil were estimated immediately after treatment, and 1, 5, 9 and 18 weeks after treatment at both the soil surface and the above-mentioned depths. The development of T. atroviride SC1 populations in the microcosms during the 18 weeks of monitoring was similar to that observed under field conditions. The dispersal of conidia was affected by the application of water to the soil. Conclusions:, Results demonstrate that this microcosm prototype can be used to model the behaviour of T. atroviride SC1 in soil. Significance and Impact of the Study:, The intact soil-core microcosm is a reliable, easy-to-use, fast and cheap method that could also be used in studies of similar filamentous fungi to study their probable fate in the soil prior to their being introduced into the environment. [source] Production of bioactive metabolites by Nocardia levis MK-VL_113LETTERS IN APPLIED MICROBIOLOGY, Issue 4 2009A. Kavitha Abstract Aims:, To isolate and identify the bioactive compounds produced by Nocardia levis MK-VL_113. Methods and Results:, Cultural characteristics of Noc. levis isolated from laterite soils of Guntur region were recorded on International Streptomyces Project media. Morphological studies of the strain through scanning electron microscopy revealed the clear pattern of its hyphal fragmentation into rod-shaped bacilli. Chemical examination of the secondary metabolites of the strain grown on sucrose,tryptone broth led to the isolation of three fractions active against Bacillus cereus. Further analysis of second fraction resulted in the isolation of two active subfractions. Two different phthalate esters, namely, bis-(2-ethylhexyl) phthalate and bis-(5-ethylheptyl) phthalate, were purified from the first active subfraction, and the structural elucidation of these compounds was confirmed on the basis of FT-IR, mass and NMR spectroscopy. The partially purified second subfraction subjected to Gas Chromatography,Mass spectroscopy contained nine components: decanedioic acid; 2,6-piperdione monooxime; 1-eicosanol; beta-1-arabinopyranoside, methyl; cyclopentaneundecanoic acid; hexadecanoic acid; silane, trichloro eicosyl; 1-hexacosanol; and 1,2-dodecanediol. The antimicrobial activity of the bioactive compounds produced by Noc. levis was expressed in terms of minimum inhibitory concentration. Conclusions:, The present study clearly revealed that the metabolites of Noc. levis act as bioactive compounds against Gram-positive and Gram-negative bacteria, yeast and filamentous fungi. It also supports the idea that there are a number of rare actinomycetes remained to be explored for new bioactive compounds. Significance and Impact of the Study:, Metabolites of Noc. levis exhibited antibacterial and antifungal activities. This is the first report of bis-(5-ethylheptyl) phthalate as well as the nine partially purified compounds from actinomycetes. In addition, this is also the first report of bis-(2-ethylhexyl) phthalate from the genus Nocardia. [source] l -leucine aminopeptidase production by filamentous Aspergillus fungiLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2005K.M. Nampoothiri Abstract Aims:, To screen various filamentous fungi belonging to Aspergillus spp. producing leucine and methionine aminopeptidases. Methods and Results:, Twenty-eight Aspergillus strains representing 14 species within the genus were screened for l -leucine aminopeptidase (LAP) production in two media in shake flask fermentation. Two Aspergillus sojae (NRRL 1988 and NRRL 6271) and one Aspergillus oryzae (NRRL 6270) strains were selected as the best producers for further studies. The peak LAP activities were 2·61, 2·59 and 1·30 IU ml,1 for the three fungi on days 2, 5 and 4 respectively. In addition to LAP, l -methionine aminopeptidase (MAP) activity was also detected. Apart from submerged fermentation, the highest LAP yields by solid-state fermentation were 11·39, 17·40 and 13·02 IU g,1 dry matter for the above fungi. The temperature and pH optimum of the enzyme was found to be in the range of 65,75°C at pH 8·0,9·0 for all three fungi. Metal ions, Co2+ and Fe2+ in 2 mmol l,1 concentration apparently enhanced the relative enzyme activity and heat stability. Conclusions:, Two A. sojae (NRRL 1988 and NRRL 6271) and one A. oryzae (NRRL 6270) strains were found to be the best producers of LAP and MAP. The preliminary characterization studies revealed that the enzyme is considerably thermostable and belongs to the class metalloenzymes. Significance and Impact of the Study:, A good number of aspergilli were screened and the ability of the fungal aminopeptidase to release a particular N-terminal amino acid along with its high thermal stability, makes them interesting for controlling the degree of hydrolysis and flavour development for a wide range of substrate. [source] Looking through the eyes of fungi: molecular genetics of photoreceptionMOLECULAR MICROBIOLOGY, Issue 1 2007Alfredo Herrera-Estrella Summary Filamentous fungi respond to a variety of environmental signals. One of them is light, providing critical information about orientation, or impending stress. Cells of filamentous fungi appear to sense blue light through a unique transcription factor that has a flavin chromophore and activates its targets in a light-dependent manner, the white collar (WC) complex. Fungal photophysiology, though, predicted a greater complexity of responses to the whole visible spectrum. The rapidly growing fungal genome database provides candidates to explain how fungi see not only blue, but also near-UV, green and red light. At the same time, there are surprises in the genomes, including photoreceptors for which there are no obvious photoresponses. Linking these genes and their functions will help understand how a list of only a few biological chromophores accounts for such a diversity of responses. At the same time, deeper mechanistic understanding of how the WC complex functions will lead to fundamental insights at the point where the environment impinges, in this case in the form of photons, on the transcriptional machinery of the cell. [source] Mycoviruses of filamentous fungi and their relevance to plant pathologyMOLECULAR PLANT PATHOLOGY, Issue 1 2009MICHAEL N. PEARSON SUMMARY Mycoviruses (fungal viruses) are reviewed with emphasis on plant pathogenic fungi. Based on the presence of virus-like particles and unencapsidated dsRNAs, mycoviruses are common in all major fungal groups. Over 80 mycovirus species have been officially recognized from ten virus families, but a paucity of nucleic acid sequence data makes assignment of many reported mycoviruses difficult. Although most of the particle types recognized to date are isometric, a variety of morphologies have been found and, additionally, many apparently unencapsidated dsRNAs have been reported. Until recently, most characterized mycoviruses have dsRNA genomes, but ssRNA mycoviruses now constitute about one-third of the total. Two hypotheses for the origin of mycoviruses of plant pathogens are discussed: the first that they are of unknown but ancient origin and have coevolved along with their hosts, the second that they have relatively recently moved from a fungal plant host into the fungus. Although mycoviruses are typically readily transmitted through asexual spores, transmission through sexual spores varies with the host fungus. Evidence for natural horizontal transmission has been found. Typically, mycoviruses are apparently symptomless (cryptic) but beneficial effects on the host fungus have been reported. Of more practical interest to plant pathologists are those viruses that confer a hypovirulent phenotype, and the scope for using such viruses as biocontrol agents is reviewed. New tools are being developed based on host genome studies that will help to address the intellectual challenge of understanding the fungal,virus interactions and the practical challenge of manipulating this relationship to develop novel biocontrol agents for important plant pathogens. [source] Claviceps purpurea: molecular aspects of a unique pathogenic lifestyleMOLECULAR PLANT PATHOLOGY, Issue 5 2004PAUL TUDZYNSKI SUMMARY Claviceps purpurea is a ubiquitous pathogen of cereals and grasses, causing Ergot disease, which results in substitution of grains by sclerotia. These overwintering structures contain ergot-alkaloids, which can cause severe intoxication in mammals. C. purpurea is an interesting model system for the study of host,pathogen interaction. It displays strict organ specificity, attacking exclusively young grass ovaries. It is optimally adapted to this special niche of infection, probably by mimicry of pollen tubes: there are no resistance genes known, and no effective resistance reactions can be detected in the early steps of infection. In this early phase of host tissue colonization the fungus shows directed, almost unbranched growth towards the base of the ovary. Thus, C. purpurea represents one of the few systems in which directed growth in filamentous fungi can be studied. Finally, the fungus behaves as a true biotroph in planta, although it can be easily grown in axenic culture. We describe here the tools available to study this interesting pathogen, report on recent molecular investigations concerning the role of cell-wall-degrading enzymes and of reactive oxygen species in this specialized interaction, and present an update of the signalling cascades involved in early events of pathogenesis. [source] In vitro susceptibility-testing in Aspergillus speciesMYCOSES, Issue 5 2008Cornelia Lass-Flörl Summary Aspergillus species are the most common causes of invasive mould infections in immunocompromised patients. The introduction of new antifungal agents and recent reports of resistance emerging during treatment of Aspergillus infections have highlighted the need for in vitro susceptibility-testing. Various testing procedures have been proposed, including macrodilution and microdilution, agar diffusion, disc diffusion and Etest. At present, one of the most widely used assays is the M38-A reference method for filamentous fungi, published by the Clinical Laboratory Standard Institute and the Etest. Recently, the European Committee on Antimicrobial Susceptibility-testing (EUCAST) has charged its Antifungal Susceptibility-testing Subcommittee (AFST-EUCAST) with the preparation of new guidelines for in vitro susceptibility-testing of antifungals against Aspergillus spp. (EUCAST-AFST-ASPERGILLUS) defining breakpoints. This paper reviews the available methods for antifungal susceptibility-testing in Aspergillus spp. as well as the scant data regarding the clinical implications of in vitro testing. [source] Antifungal effects of aminosulphoxide and disulphide derivativesMYCOSES, Issue 3 2006Veerle Wittebolle Summary 2-Benzenesulphinyl-(1,4)-naphtoquinone and 14 derivatives were synthesised and were used to evaluate their cytotoxicity against a human myelomonocyte cell line and their antifungal activity against two yeast, i.e. Candida albicans and C. tropicalis and against two filamentous fungi such as Aspergillus niger and Fusarium oxysporum and against one dermatophyte, namely Trichophyton tonsurans. The cytotoxicity and antifungal activities were investigated in comparison with amphotericin B as reference drug. No compound was significantly more toxic than amphotericin B at 0.2 ,g ml,1. The best results of antifungal activity were obtained with GFL 10, GFL 13 and GFL 30 on C. tropicalis, F. oxysporum and T. tonsurans. For C. albicans and A. niger, there was no difference between amphotericin B and the other molecules. The sterol quantitation, the time-kill curves were carried out for these three compounds in order to confirm their action in ergosterol synthesis. Time-kill curves showed a fungistatic activity. For C. tropicalis GFL 10, GFL 13 and GFL 30 increased the growth delay better than amphotericin B, in contrast to F. oxysporum. As for T. tonsurans, GFL10 and GFL13 gave a delay, but the effect of GFL 30 was a bit less marked. [source] The incidence of opportunistic fungi in patients suspected of tuberculosisMYCOSES, Issue 7-8 2000M. Chadeganipour Summary The incidence of opportunistic fungi in bronchoalveolar lavage specimens from patients suspected of tuberculosis in Isfahan, Iran, was determined. From 200 patients 36 yeasts (18%) and seven filamentous fungi (3.5%) were isolated. Out of 44 patients who had fungal infections, 12 cases were affected with definite tuberculosis. [source] The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29ArpNEW PHYTOLOGIST, Issue 2 2009M. Barret Summary ,,In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. ,,An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. ,,During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. ,,Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial,fungal cell contact. [source] | |||||||||||||||||||||||||||||||||||||