Academic literature on the topic 'Filamentous fungi Aspergillus. Mycology. Mucor'

Hyphal growth in filamentous fungi proceeds in an unidirectional radial pattern from a point inoculation. An inhibitor produced, secreted, and absorbed by the advancing hyphae has been speculated to account for directional growth. Working with Mucor and Aspergillus, laboratory evidence is provided for the production of an inhibitor by the advancing hyphae of these filmentous fungi that precludes back growth. Strains of Mucor and Aspergillus inoculated in agar on a 0.45-mm membrane filter placed on agar surfaces grow radially beyond the filter perimeter and onto the agar surface. Removal of the filter pad does not result in hyphal extension back into the clear zone underlying the membrane filter. Inoculation of the clear zone with a fresh Mucor or Aspergillus spore suspension does not result in hyphal growth. Instead, germinating spores show aberrant and aborted hyphae. The fungal inhibitor shows cross-reactivity between Mucor and Aspergillus, is resistant to pronase (10 mg/mL) but not chloroform inactivation, and passes through dialysis tubing with a molecular weight cutoff of 3500.Key words: fungal inhibitor, unidirectional hyphal growth, radial hyphal growth, Mucor, Aspergillus.

Abstract The cereals are a suitable substrate for the growth of microscopic filamentous fungi. Micromycetes are capable of reducing the nutritional value of feedstuff and they can produce several mycotoxins. The most frequent genera of microscopic filamentous fungi are Fusarium, Penicillium, Alternaria and Aspergillus. The contamination by microscopic fungi and mycotoxins was determinated in 56 samples of feed cereals originating from the Slovak Republic. The most common genera of fungi detected in the feed cereals included: Alternaria (67.8 %), Fusarium (44.6 %), Penicillium (39.2 %), Mucor (30.3 %), Rhizopus (28.5 %), Cladosporium (21.4 %), Scopulariopsis (8.9 %) and Aspergillus (1.7 %). Deoxynivalenol was present in 24 samples (42.8 %) and zearalenone in 15 samples (26.7 %). The values of both mycotoxins did not reach the regulatory limits and thus they do not pose a risk to livestock nutrition.

ABSTRACT This study aimed to validate the effectiveness of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS)-based identification of filamentous fungi of the order Mucorales. A total of 111 isolates covering six genera preserved at the Research Center for Medical Mycology of Peking University were selected for MALDI-TOF MS analysis. We emphasized the study of 23 strains of Mucor irregularis predominantly isolated from patients in China. We first used the Bruker Filamentous Fungi library (v1.0) to identify all 111 isolates. To increase the identification rate, we created a compensatory in-house database, the Beijing Medical University (BMU) database, using 13 reference strains covering 6 species, including M. irregularis, Mucor hiemalis, Mucor racemosus, Cunninghamella bertholletiae, Cunninghamella phaeospora, and Cunninghamella echinulata. All 111 isolates were then identified by MALDI-TOF MS using a combination of the Bruker library and BMU database. MALDI-TOF MS identified 55 (49.5%) and 74 (66.7%) isolates at the species and genus levels, respectively, using the Bruker Filamentous Fungi library v1.0 alone. A combination of the Bruker library and BMU database allowed MALDI-TOF MS to identify 90 (81.1%) and 111 (100%) isolates at the species and genus levels, respectively, with a significantly increased accuracy rate. MALDI-TOF MS poorly identified Mucorales when the Bruker library was used alone due to its lack of some fungal species. In contrast, this technique perfectly identified M. irregularis after main spectrum profiles (MSPs) of relevant reference strains were added to the Bruker library. With an expanded Bruker library, MALDI-TOF MS is an effective tool for the identification of pathogenic Mucorales.

ABSTRACT Posaconazole, ravuconazole, and voriconazole are new triazole derivatives that possess potent, broad-spectrum antifungal activity. We evaluated the in vitro activity of these investigational triazoles compared with that of itraconazole and amphotericin B against 239 clinical isolates of filamentous fungi from the SENTRY Program, including Aspergillus spp. (198 isolates), Fusarium spp. (7 isolates), Penicillium spp. (19 isolates), Rhizopus spp. (4 isolates), Mucor spp. (2 isolates), and miscellaneous species (9 isolates). The isolates were obtained from 16 different medical centers in the United States and Canada between January and December 2000. In vitro susceptibility testing was performed using the microdilution broth method outlined in the National Committee for Clinical Laboratory Standards M38-P document. Overall, posaconazole was the most active compound, inhibiting 94% of isolates at a MIC of ≤1 μg/ml, followed by voriconazole (91%), amphotericin B (89%), ravuconazole (88%), and itraconazole (70%). All three new triazoles demonstrated excellent activity (MIC, ≤1 μg/ml) against Aspergillus spp. (114 Aspergillus fumigatus, 22 Aspergillus niger, 13 Aspergillus flavus, 9 Aspergillus versicolor, 8 Aspergillus terreus, and 32 Aspergillus spp.): posaconazole (98%), voriconazole (98%), ravuconazole (92%), amphotericin B (89%), and itraconazole (72%). None of the triazoles were active against Fusarium spp. (MIC at which 50% of the isolates tested were inhibited [MIC50], >8 μg/ml) or Mucor spp. (MIC50, >8 μg/ml). Posaconazole and ravuconazole were more active than voriconazole against Rhizopus spp. (MIC50, 1 to 2 μg/ml versus >8 μg/ml, respectively). Based on these results, all three new triazoles exhibited promising activity against Aspergillus spp. and other less commonly encountered isolates of filamentous fungi. The clinical value of these in vitro data remains to be seen, and in vitro-in vivo correlation is needed for both new and established antifungal agents. Surveillance efforts should be expanded in order to monitor the spectrum of filamentous fungal pathogens and their in vitro susceptibility as these new antifungal agents are introduced into clinical use.

Use of MALDI-TOF mass spectrometry to identify yeast and molds in animal feed. The material for the work was animal feed samples received for research from diff erent regions of Ukraine. The presence of yeast and molds was determined according to DSTU ISO 7954:2006. To establish the general contamination of the feed with micromycetes, the fungi were fi rst isolated from the feed by planting them on Saburo medium, and the serial dilution method was used to calculate the content of fungi diaspores in 1 g of feed. The feed samples were incubated and studied at a temperature of 24 ° C for 5–7 days. The identifi cation of molds was carried out using the MALDI-TOF method. In the process of mycological examination of feed during 2018–2019. 198 animal feed samples were examined. During the study period, the largest number of feed was examined, which was 30.4% in 2018, of the total number of samples (19.6% - feed for poultry, 10.8% - for pigs). For fi ve months of 2019, we observed the same trend: in 31.1% of cases, the defi nitions of yeast and molds in compound feeds prevailed, of which 19.8% accounted for compound feeds for poultry and in 11.3% of cases for pigs. In second place in the number of studies, corn samples are 11.9 and 11.3% in 2018 and 2019, respectively. The most common types of fungi in the feed were representatives of the genera Fusarium, Penicillium, Aspergillus, Alternaria, Mucor, Rhizopus, Cladosporium. The affi liation of microscopic fungi to specifi c genera was determined by assessing the morphology of the fungal colony on media and the morphology of conidiophore structures Particular attention was paid to microscopic fungi of the Fusarium family, which are producers of various mycotoxins. Using the MALDI Biotyper software, automatic identifi cation was performed based on a comparison of the collected initial spectra of the fungus with the reference spectra of the database of the instrument itself, as well as with the library of the University of Belgium (BCCM, Belgian Co-Ordinateo collections of micro-organism). Following the results of mass spectrometry, microscopic fungi of the Fusarium family were represented by 9 species. Of these, 5 species were most often found: F. proliferatum, F. acutatum, F. subglutinans, F. verticillioides. Among the fungi of the Aspergillus family, A. fl avus, A. pseudoglaucus, A. tubingensis, and A. niger predominated. Species identifi cation of microscopic fungi using mass spectrometry helps quickly and accurately identify mold fungi and yeast. Determination of the species affi liation of microscopic organisms occurs through analysis of the protein fraction of the lysate of microscopic fungi and yeast ("direct protein profi ling"). MALDI Biotyper software includes automatic identifi cation of molds based on a comparison of the output spectra with the reference spectra of the database. Identifi cation of microorganisms using MALDI-TOF MS is based on the assessment of ribosomal proteins that are usually present in the cell. The sensitivity of the MALDI-TOF MS method is 103106 m.k./cm. In this case, the accuracy of identifi cation depends on the amount of test material. To determine the likelyhood of identifi cation, a given logarithmic indicator is the compliance coeffi cient Score, the value of which is used to evaluate the reliability and adequacy of the results. The higher the match rate, the more likely it is to get the correct identifi cation result. MALDI-TOF technology for mass spectrometric identifi cation of micromycetes has a high measurement speed, low cost of reagents and materials used, and simple preparation holes. MALDI-TOF MS has a high diagnostic sensitivity. Key words: mold identifi cation, MALDI-TOF, mass spectrometry, Fusarium, Penicillium, Aspergillus, Alternaria, Mucor, Rhizopus, Cladosporium.

Condiments are products of natural origin, with or without nutritional value, used in food in order to modify or enhance the flavor. However, these can be contaminated by bacteria and fungi during storage, transport or handling. The aim of this work was to research filamentous fungi in four of the most sold types of dehydrated spices at Port market, Cuiabá-MT: oregano (Origanum vulgare L.), rosemary (Rosmarinus officinalis L.), basil (Ocimum basilicum L.) and black pepper (Piper nigrum L.). For this, 200 g of each spice were acquired and, the collection was done in three periods of time, February, July and December 2014, totaling 12 samples. Fungal species were inoculated with Sabouraud agar with chloramphenicol, with subsequent fungal count and ultrastructure of fungal genera. The basil and black pepper were the spices that had higher fungal count (> 100 CFU / g) and rosemary the lowest score (2.8 x 101 CFU / g). The following were isolated filamentous fungi: Absidia spp; Alternaria spp; Aspergillus spp; Cladosporium spp; Mycelia sterilia; Mucor spp; Paecylomyces spp and Penicillium spp, and the genera Aspergillus was the most frequent (n = 165/67%). The presence of different types of filamentous fungi suggests that the conditions of production, storage and manipulation in the analyzed point of sale are not appropriate, making the spices evaluated susceptible to microbiological contamination.

Honey is a remarkably complex food with a valued place in the human diet. An important indicator of its quality is the presence of microorganisms. This study aimed to monitor the mycological quality of 27 samples of Slovak kinds of honey and honey products with the addition of differently processed blueberries, cranberries, and red currants. Yeast and filamentous microscopic fungi were monitored using the plate dilution method. A total of 21 samples (78%) were positive for the presence of yeasts and 14 samples (52%) were positive for the filamentous microscopic fungi occurrence. In 6 samples (22%) no presence of microscopic fungi was found at all. The highest number of yeasts (3.07 log CFU.g-1) was recorded in one flower honey sample and in other samples, yeast counts did not exceed 3 log CFU.g-1. The highest numbers of filamentous micromycetes (2.39 and 2.44 log CFU.g-1) were recorded in 2 honeydew honey samples. Overall, the following genera have been identified: Alternaria, Arthrinium, Aspergillus (including previously named as Eurotium), Aureobasidium, Cladosporium, Mucor, Penicillium, and Stemphilium. Penicillium spp. were recorded with the highest isolation frequency (41%). Aspergillus species were isolated from 19% of honey samples. In the honey with fruit addition, the yeasts in a range of 1.00 – 3.09 log CFU.g-1 and the filamentous microscopic fungi in a range of 1.00 – 1.39 log CFU.g-1 were found. The study showed that cranberries were the most appropriate addition from a mycological point of view. Dried and lyophilized forms of tested fruits were the most suitable. Except for honey with frozen currants and honey with fresh cranberries, all final products had a water activity below 0.610 and appeared to be stable.

Filamentous fungi were isolated from ten spices collected from markets in Indonesia. The aim was to enumerate fungal contamination and to determine the toxigenicity of Aspergillus flavus strains on each of the spices. Viable fungal populations were determined using a dilution method. Toxigenicity of Aspergillus flavus was determined by culture on a quick screening coconut agar and by PCR using four sets of primers specific for aflatoxin pathway genes. All the tested spices were contaminated by storage fungi, Species of Aspergillus was the most commonly isolated moulds followed by species of Fusarium, Mucor, Penicillium and Rhizopus. The greatest number of Aspergillus flavus isolates were found on white pepper, followed by nutmeg, cardamom, and black pepper. The greatest number of Aspergillus chevalieri isolates were found on coriander, followed by nutmeg. Fifty strains of A. flavus were isolated, all of the strains produced large sclerotia and biseriate conidiophores. Their toxigenicity was assayed by the presence of yellow pigment on a quick screening coconut agar medium and PCR amplification of regulatory and structural genes in the aflatoxin pathway.

The consumption of food contaminated with moulds (microscopic filamentous fungi) and their toxic metabolites results in the development of food-borne mycotoxicosis. The spores of moulds are ubiquitously spread in the environment and can be detected everywhere. In this study, the presence of various moulds was determined in pork and beef used as a raw material, in salami emulsions, as well as in five kinds of fermented raw meat products. Penicillium sp., Acremonium sp., Mucor sp., Cladosporium sp., and Aspergillus sp. were the most frequently isolated genera of moulds. Flavourings added to meat during the production of fermented raw meat products were heavily contaminated with moulds. The widest spectrum and the highest counts of microscopic filamentous fungi were observed in the following spices: milled black pepper, nutmeg, garlic powder and crushed caraway. The level of contamination depended upon the season, being higher in the summer months.  

The identification of the diversity of microscopic fungi of lithobiont communities of the Argentine Islands in specimens collected during the 22nd Ukrainian Antarctic Expedition was the purpose of this work. Samples of rock, soil, mosses and lichens of rock micro-habitats of “Crustose lichen sub-formation and fruticose lichen and moss cushion sub-formation” were used in the work. These samples were used for extracting and cultivation of filamentous fungi on dense nutrient media. Determination of physiological and biochemical characteristics and identification of yeast-like fungi were performed using a microbiological analyser ‘Vitek-2’ (‘Bio Merieux’, France). Cultivation of microorganisms was carried out at temperatures from +2 to +37 °C. In results cultures of microscopic fungi of Zygomycota (Mucor circinelloides), Ascomycota (species of the genera cf. Tlielebolus, Talaromyces), representatives of the Anamorphic fungi group (Geomyces pannorum, species of the genera Alternaria, Acremonium, Aspergillus, Penicillium, and Cladosporium) were isolated from Antarctic samples. Microscopic fungi Penicillium spp. were dominated after the frequency in the studied samples (54.5%). Rhodotorula rubra and Candida sp. among isolated yeast fungi, and dark pigmented fungi represented by Aureobasidium pulhdans and Exophiala spp. were identified. The biological properties of a number of isolated fungi (the potential ability to synthesise important biologically active substances: melanins, carotenoids, lipids) are characterised. Mycobiota of rock communities of Argentine Islands is rich on filamentous and yeast fungi similarly to other regions of Antarctica. A number of fungi investigated are potentially able to synthesise biologically active substances. The dark pigmented species of the genera Cladosporium, Exophiala, Aureobasidium pulhdans, capable of melanin synthesis; ‘red’ yeast Rhodotorula rubra (carotenoid producers and resistant to toxic metals); Mucor circinelloides and Geomyces pannorum, lipid producers, are among these fungi. Yeast-like fungi assimilated a wide range of carbohydrates, which will allow them to be further used for cultivation in laboratory and process conditions. The collection of technologically promising strains of microorganisms, part of the Culture Collection of Fungi at Taras Shevchenko National University of Kyiv (Ukraine), is updated with isolated species (strains) of filamentous fungi and yeast – potential producers of biologically active substances, obtained within this study.