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Lipolytic activity and degradation of rapeseed oil and rapeseed by spoilage fungi.

Aspergillus, Eurotium and Penicillium spp. from rapeseed were able to grow and produce lipases over a range of water activities (aw) at both 15 and 25 degrees C on tributyrin agar. The ability to produce lipases was not directly related to growth rate. The clearing zone: growth rate ratios gave lipase indices which varied markedly between test fungi and with aw. The fungi with the highest indices were Aspergillus candidus and Aspergillus versicolor and Penicillium expansum and Penicillium hordei. The Aspergillus spp. generally grew faster on a 1% crude rapeseed oil at 25 degrees C and 0.995 and 0.95 aw than on the tributyrin agar. P. hordei degraded the rapeseed oil more rapidly than Eurotium amstelodami or Penicillium aurantiogriseum, with optimum activity at 0.98 aw. E. amstelodami was the least effective at degrading the rapeseed oil under all aw conditions. The lipase indices were compared with the ability of the test fungi to degrade irradiated rapeseed. Dry matter loss over 4-week periods were greater at 25 than 15 degrees C, regardless of aw. At 15 degrees C, Penicillium spp. caused significantly greater dry matter losses than Aspergillus spp. A. niger degraded rapeseed faster than other Aspergillus spp. tested at 0.98 aw, but at 0.95 and 0.90 aw there was little difference between species.

Ascomycota↗

Evaluation of modified dichloran 18% glycerol (DG18) agar for enumerating fungi in wheat flour: a collaborative study.

Dichloran 18% glycerol agar base supplemented with 100 micrograms of chloramphenicol ml-1 (DG18 agar) was compared to DG18 agar supplemented with 100 micrograms of Triton X-301 ml-1 (DG18T) and DG18 agar supplemented with 1 microgram of iprodione [3-(3,5-dichlorophenyl)-N-(1-methyl-ethyl)-2,4-dioxo-1-imidazolidine- carboxamide] ml-1 (DG18I agar) for enumeration of fungi in ten brands of wheat flour. As the flours contained low fungal populations, all were inoculated with two to four strains of xerophilic fungi (Aspergillus candidus, A. penicillioides, Eurotium amstelodami, E. intermedium, E. repens, E. rubrum, E. tonophilum, E. umbrosum and Wallemia sebi), after which counts ranged from 3.87 to 6.37 log10 CFU g-1. Significantly higher populations (p < 0.05) were detected in four flours: three were on DG18T compared to DG18 and DG18I agar. A. candidus had been inoculated into all three flours. E. amstelodami, E. intermedium, E. repens or E. tonophilum had also been inoculated into at least one of the three flours showing significantly higher numbers of CFU on DG18T agar. Analysis of collapsed data from all samples showed that DG18T agar was significantly better than DG18 or DG18I agars at p < 0.10 but not at p < 0.05. Coefficients of variation for reproducibility (among-laboratory variation) were 8.4%, 7.5% and 8.6%, respectively, for DG18, DG18T and DG18I agars. DG18I agar restricted colony development most, especially for Eurotium species. Naturally occurring Penicillium species grew equally well on DG18 and DG18T agars, whereas W. sebi grew well on all three media. DG18T agar was judged to be superior to DG18 and DG18I agars for enumerating fungi in wheat flours.

Aminoimidazole Carboxamide↗

Reduction of Haemonchus contortus infective larvae by three nematophagous fungi in sheep faecal cultures.

The reduction of Haemonchus contortus (L3) infective larvae in sheep faecal cultures caused by the action of three nematophagous fungi conidia was evaluated in vitro. Addition of 20,000 conidia of Monacrosporium eudermatum, Arthrobotrys oligospora and Arthrobotrys robusta per gram of faeces caused a reduction of 95.7%, 98.3% and 10.1%, respectively, compared with the control group. A 97.4% reduction was observed when combined conidia of the three fungi were used. Total reduction of the larval population was observed by addition of the three fungi at 100,000 conidia per gram of faeces.

Animals↗

The potential of nematophagous fungi to control the free-living stages of nematode parasites of sheep: in vitro and in vivo studies.

Following in vitro screening investigations on approximately 100 nematophagous fungi reported previously, eight species were selected for further investigation. Fungal elements (mycelium and conidia) were subjected to in vitro stress selection designed to simulate rumen and abomasal conditions. From these studies, three species, namely, Arthrobotrys oligospora, Arthrobotrys oviformis and Geniculifera eudermata, were selected for in vivo survival studies in sheep surgically fitted with abomasal and ileal cannulae. Doses of fungal conidia were administered orally or via the abomasal cannulae and samples of digesta were taken from the abomasum, the terminal ileum and faeces. The viability of the three fungal species at these sites was demonstrated. The abundance of fungi throughout the gut was dose-dependent but in all cases only very small volumes of fungal suspension containing unprotected conidia were used. These results demonstrate that a practical means of orally administering nematophagous fungi to control free-living stages of nematodes in faeces may become an achievable objective.

Abomasum↗

Denitrification by fungi.

Many fungi in the centre of the group of Fusarium and its teleomorphs were shown to be capable of reducing nitrite anaerobically to form nitric oxide (NO), nitrous oxide (N2O), and/or dinitrogen (N2). Several strains could reduce nitrate as well. Nitrous oxide was the major product of the reduction of nitrate or nitrite. Several fungi could also form N2. When [15]nitrite was used as substrate for the N2-forming denitrification, 15N2O, 15NO, and 14N15N were obtained as the products. These results demonstrated that, unexpectedly, many fungi have denitrifying abilities. It was also shown that the fungal system contains a unique reaction, formation of a hybrid dinitrogen.

Anaerobiosis↗

Identification of peptide synthetase-encoding genes from filamentous fungi producing host-selective phytotoxins or analogs.

Race 1 of Cochliobolus carbonum (Cc) makes a cyclic tetrapeptide, HC-toxin, that is necessary for its virulence on certain genotypes of maize. The synthesis of HC-toxin is catalyzed by a 570-kDa multifunctional enzyme, HC-toxin synthetase (HTS). The gene encoding HTS (HTS1) is absent from other races of Cc and from other species of Cochliobolus. Four other unrelated filamentous fungi make cyclic peptides closely related to HC-toxin, raising the possibility that the corresponding cyclic peptide synthetase (CPS)-encoding genes have moved between these fungi by horizontal gene transfer. Degenerate PCR primers were designed based on several highly conserved amino acid (aa) motifs common to known CPS domains and used to amplify genomic sequences from different fungi. PCR products representing CPS genes from Diheterospora chlamydosporia, which makes the HC-toxin analog chlamydocin, Cylindrocladium macrosporum, which makes the analog Cyl-2, and C. victoriae, which makes the unrelated cyclic pentapeptide victorin, were cloned and analysed. Their sequences are more related to HTS1 than to other cloned CPS, but the percent aa identity is not consistent with very recent horizontal movement of these genes.

Amino Acid Isomerases↗

Inhibitory effects of fungi on aggregation of rabbit platelets and rat polymorphonuclear leucocytes in vitro.

Fungi of six families, encompassing 28 species, have been screened for their inhibitory effects on adenosine-5'-diphosphate (ADP), acetyl-glyceryl-phosphorylcholine (PAF) or collagen-induced rabbit platelet aggregation. Some fungi have also been studied for their ability to inhibit neutrophil aggregation induced by calcium ionophore A 23187. The results suggest that fungi may be a potential source of inhibitors of platelet and neutrophil aggregation.

Adenosine Diphosphate↗

Species identification and chemical analysis of psychoactive fungi in the Hawaiian islands.

Several fungi species collected in the Hawaiian Islands have been reported to be psychoactive. Previous chemical analyses together with the present study indicate that 5 coprophilous and one non-coprophilous species occurring in the islands are now known to contain psychoactive alkaloids. At least some of these species are consumed in the Hawaiian Islands, as well as elsewhere, for non-traditional, recreational purposes. These include Copelandia cyanescens (Berk. et Br.) Singer, Copelandia tropicalis (Ola'h) Singer and Weeks (syn. Panaeolus tropicalis Ola'h), Copelandia anomala Murrill, and Panaeolus subbalteatus (Berk. and Br.) Sacc., which have already been described from the Hawaiian Islands. Three more mind-altering fungi and one non-psychoactive species are reported from this archipelago for the first time. These psychoactive fungi include Copelandia bispora (Malençon et Bertault) Singer and Weeks from O'ahu, Copelandia cambodginiensis (Ola'h et Heim) Singer and Weeks from O'ahu, and Amanita muscaria (L.) Hooker from Kaua'i. Panaeolus goossensiae Beeli identified from O'ahu contains tryptamine compounds; however, the psychoactive alkaloids psilocybin and psilocin were not found in this dung species.

Animals↗

Use of carbohydrate and nitrate assimilations in the identification of dematiaceous fungi.

A total of 61 isolates of dematiaceous fungi, including Exophiala jeanselmei, Wangiella dermatitidis, Fonsecaea pedrosoi, Phialophora verrucosa, and a few isolates of related organisms were evaluated for their ability to assimilate 13 carbohydrates and sodium nitrate. Results indicated that patterns of assimilations can facilitate specific identifications when used with microscopic morphologic features. Eleven isolates of W. dermatitidis demonstrated negative results for nitrate assimilation, although most of the other fungi tested had positive reactions. The tests did aid in separating this very complex group of fungi.

Carbohydrate Metabolism↗

The role of fungi in the etiology of chronic rhinosinusitis: a prospective study.

OBJECTIVES: Allergic fungal sinusitis (AFS) may represent an endpoint in a spectrum of sinonasal disease. Patients fulfilling criteria for a diagnosis of AFS have a poor prognosis often requiring multiple surgeries. The detection of 'allergic mucin' with mucus containing clusters of eosinophils and the detection of fungi by histological examination or culture is key criteria necessary for diagnosis. This study was performed to assess the strength of the association of the presence of fungi with the presence of eosinophils in a group of patients with chronic rhinosinusitis and controls. METHODS: Thirty patients with a clinical diagnosis of chronic rhinosinusitis and 10 individuals as control group were selected for the study. Total serum IgE level testing, nasal mucus cytology and fungal culture were performed in all subjects. RESULTS: Fungal spores were present in the nasal mucus in 14 patients with rhinosinusitis, and in 7 controls. The detection of eosinophils on cytology correlated significantly both with a clinical diagnosis of chronic rhinosinusitis (95% confidence intervals (CI) 0.34-0.81) and with the presence of fungal elements on cytology (p=0.02). The average serum IgE level was higher in patients with fungal spores (p=0.039). CONCLUSION: In certain susceptible individuals inhaled fungi may provoke an eosinophilic response. This response varies from simple eosinophilic inflammation to classic allergic fungal sinusitis.

Adolescent↗

Immunity to fungi.

Innate and adaptive immune responses target pathogenic fungi and provide defense against fungal infections. Recent studies demonstrate that specific host receptors recognize ligands that are unique to fungi and activate signaling cascades that lead to phagocytosis of fungi, generation of pro-inflammatory mediators, formation of reactive oxygen species, trafficking of inflammatory cells to sites of infection, and initiation of adaptive immune responses. Greater understanding of the molecular mechanisms that underlie antifungal defense has provided a framework for the investigation of protective vaccines and strategies for therapeutic adoptive cell transfer.

Animals↗

Extensive set of mitochondrial LSU rDNA-based oligonucleotide probes for the detection of common airborne fungi.

Fungi exist in every indoor and outdoor environment. Many fungi are toxigenic or pathogens that may cause various public health concerns. Rapid and accurate detection and identification of fungi require specific markers. In this study, partial mitochondrial large subunit rDNA was amplified and sequenced from 32 fungal strains representing 31 species from 14 genera. Based on the sequence variation pattern, 26 oligonucleotide probes were designed for their discrimination. The specificity of the probes was evaluated through homology search against GenBank database and hybridization examination on 38 fungal strains. The 26 probes were verified as highly specific to 20 fungal species. A two-step detection procedure through PCR followed by probe hybridization gave ten-fold increase in detection sensitivity than single-step PCR assay and would be a practical approach for environmental sample screening. The probes developed in this study can be applied in clinical diagnosis and environmental monitoring of fungal agents.

Air Microbiology↗

Transcriptional regulation of plant cell wall degradation by filamentous fungi.

Plant cell wall consists mainly of the large biopolymers cellulose, hemicellulose, lignin and pectin. These biopolymers are degraded by many microorganisms, in particular filamentous fungi, with the aid of extracellular enzymes. Filamentous fungi have a key role in degradation of the most abundant biopolymers found in nature, cellulose and hemicelluloses, and therefore are essential for the maintenance of the global carbon cycle. The production of plant cell wall degrading enzymes, cellulases, hemicellulases, ligninases and pectinases, is regulated mainly at the transcriptional level in filamentous fungi. The genes are induced in the presence of the polymers or molecules derived from the polymers and repressed under growth conditions where the production of these enzymes is not necessary, such as on glucose. The expression of the genes encoding the enzymes is regulated by various environmental and cellular factors, some of which are common while others are more unique to either a certain fungus or a class of enzymes. This review summarises our current knowledge on the transcriptional regulation, focusing on the recently characterized transcription factors that regulate genes coding for enzymes involved in the breakdown of plant cell wall biopolymers.

Biodegradation, Environmental↗

Hydrophobins: the protein-amphiphiles of filamentous fungi.

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.

Amino Acid Sequence↗

Biomechanical evidence for convergent evolution of the invasive growth process among fungi and oomycete water molds.

Diverse microorganisms traditionally called fungi are recognized as members of two kingdoms: mushroom-forming species and their relatives in the Fungi, and oomycete water molds in the Stramenopila. Phylogenetic analysis suggests that these kingdoms diverged early in the evolution of eukaryotes. The phylogenetic detachment of the fungi and oomycetes is reflected in radical differences in their biochemistry, cell structure, and development. In terms of their biological activities, however, they show great similarity, because both groups form colonies of filamentous hyphae that invade and decompose solid food sources. Here we present biomechanical evidence of the convergent evolution of the invasive growth process in these microorganisms. Using miniature strain gauges to measure the forces exerted by single hyphae, we show that the hyphae of species in both kingdoms exert up to 2 atmospheres of hydrostatic pressure as they extend at their tips. No other eukaryotes have adopted this process for meeting their nutritional needs.

Biological Evolution↗

Mycological survey of ripped service tree fruits (Sorbus domestica L.) with an emphasis on toxinogenic fungi.

To investigate a possible incidence of microscopic fungi in ripped service tree (Sorbus domestica L.) fruits, a mycological survey was carried out during October-November 2003 in Slovakia. This rare kind of fruit is renowned for its significant curative actions in various human and animal diseases. The study revealed that all 24 surface sterilized fruits analysed were contaminated with fungi. The most dominant endogenous contaminant encountered was Cladosporium cladosporioides (Fres.) de Vries followed by Alternaria alternata (Fr.) Keissler and Penicillium expansum Link with 88%, 63% and 54% frequency, respectively. Furthermore, 24 other fungal species were associated with the fruits as well. P. expansum (40), P. carneum (Frisvad) Frisvad/Penicillium paneum Frisvad (35) and P. griseofulvum Dierckx (6) isolates recovered from the fruits were screened by an agar plug method for production of mycotoxin patulin, all with positive results. In addition, citrinin, griseofulvin and zearalenon production by appropriate species isolates were detected. Despite of a limited number of samples of the service tree fruits examined during this study, it was concluded that the ripening of service tree fruits is accompanied with the presence of typical rotting-fungi as well as of some others, which have not previously been reported in connection with fruit. Furthermore, it was suggested that the ripped service tree fruits should be considered as a potential source of significant fungal secondary metabolites including mycotoxins. Secondary metabolite profiles of the species identified during the study were included here.

Colony Count, Microbial↗

Air sampling of Aspergillus fumigatus and other thermotolerant fungi: comparative performance of the Sartorius MD8 airport and the Merck MAS-100 portable bioaerosol sampler.

The purpose of our field study was to compare the performance of two portable bioaerosol samplers (Sartorius MD8 airport, and Merck MAS-100) for sampling Aspergillus fumigatus and other airborne thermotolerant fungi. From October 2001 to November 2001, a total of 336 samples were analyzed at 12 sampling days. During the sampling period fungal plate counts ranged from <1 to 300 CFU/m(3) for total thermotolerant fungi and from <1 to 76 CFU/m(3) for A. fumigatus. As compared to the MD8, the relative recovery of the MAS 100 was 0.96 for total thermotolerant fungi and 0.84 for A. fumigatus. We found a good correlation (Pearson's r=0.94 for single, 0.95 for the mean of two, and 0.96 for the mean of three sequential samples) between both portable bioaerosol samplers. The spectrum of thermotolerat fungal genera and Aspergillus species showed only minor differences. We conclude that under the given conditions the results of both samplers are approximately comparable.

Aerosols↗

Diffusible and volatile compounds produced by an antagonistic Bacillus subtilis strain cause structural deformations in pathogenic fungi in vitro.

An efficient antagonistic strain of Bacillus subtilis, originally isolated from the rhizosphere of established tea bushes, was found to cause structural deformities in six pathogenic fungi under in vitro culture conditions. This effect was attributed to the production of diffusible and volatile antifungal compounds. Out of the selected test fungi four were phytopathogenic, while the remaining two were of clinical importance. The bacterial strain successfully restricted the growth of all test fungi in dual cultures, and induced morphological abnormalities such as mycelial and conidial deviations. The inhibitory effect caused by volatiles was greater than that by diffusible compounds.

Antibiosis↗