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Current Biology : CB Mar 2022The horizontal transfer of large gene clusters by mobile elements is a key driver of prokaryotic adaptation in response to environmental stresses. Eukaryotic microbes...
The horizontal transfer of large gene clusters by mobile elements is a key driver of prokaryotic adaptation in response to environmental stresses. Eukaryotic microbes face similar stresses; however, a parallel role for mobile elements has not been established. A stress faced by many microorganisms is toxic metal ions in their environment. In fungi, identified mechanisms for protection against metals generally rely on genes that are dispersed within an organism's genome. Here, we discover a large (∼85 kb) region that confers tolerance to five metal/metalloid ions (arsenate, cadmium, copper, lead, and zinc) in the genomes of some, but not all, strains of a fungus, Paecilomyces variotii. We name this region HEPHAESTUS (Hφ) and present evidence that it is mobile within the P. variotii genome with features characteristic of a transposable element. HEPHAESTUS contains the greatest complement of host-beneficial genes carried by a transposable element in eukaryotes, suggesting that eukaryotic transposable elements might play a role analogous to bacteria in the horizontal transfer of large regions of host-beneficial DNA. Genes within HEPHAESTUS responsible for individual metal tolerances include those encoding a P-type ATPase transporter-PcaA-required for cadmium and lead tolerance, a transporter-ZrcA-providing tolerance to zinc, and a multicopper oxidase-McoA-conferring tolerance to copper. In addition, a subregion of Hφ confers tolerance to arsenate. The genome sequences of other fungi in the Eurotiales contain further examples of HEPHAESTUS, suggesting that it is responsible for independently assembling tolerance to a diverse array of ions, including chromium, mercury, and sodium.
Topics: Byssochlamys; Cadmium; Copper; DNA Transposable Elements; Zinc
PubMed: 35063120
DOI: 10.1016/j.cub.2021.12.048 -
Foods (Basel, Switzerland) Feb 2023This study tested hyperbaric storage (25-150 MPa, for 30 days) at room-temperature (HS/RT, 18-23 °C) in order to control the development of ascospores in apple juice....
This study tested hyperbaric storage (25-150 MPa, for 30 days) at room-temperature (HS/RT, 18-23 °C) in order to control the development of ascospores in apple juice. In order to mimic commercially pasteurized juice contaminated with ascospores, thermal pasteurization (70 and 80 °C for 30 s) and nonthermal high pressure pasteurization (600 MPa for 3 min at 17 °C, HPP) took place, and the juice was afterwards placed under HS/RT conditions. Control samples were also placed in atmospheric pressure (AP) conditions at RT and were refrigerated (4 °C). The results showed that HS/RT, in samples without a pasteurization step and those pasteurized at 70 °C/30 s, was able to inhibit ascospore development, contrarily to samples at AP/RT and refrigeration. HS/RT for samples pasteurized at 80 °C/30 s evidenced ascospore inactivation, especially at 150 MPa, wherein an overall reduction of at least 4.73 log units of ascospores was observed to below detection limits (1.00 Log CFU/mL); meanwhile, for HPP samples, especially at 75 and 150 MPa, an overall reduction of 3 log units (to below quantification limits, 2.00 Log CFU/mL) was observed. Phase-contrast microscopy revealed that the ascospores do not complete the germination process under HS/RT, hence avoiding hyphae formation, which is important for food safety since mycotoxin development occurs only after hyphae formation. These findings suggest that HS/RT is a safe food preservation methodology, as it prevents ascospore development and inactivates them following commercial-like thermal or nonthermal HPP pasteurization, preventing mycotoxin production and enhancing ascospore inactivation.
PubMed: 36900495
DOI: 10.3390/foods12050978 -
Persoonia Jun 2009Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all...
Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all Byssochlamys species was carried out using a polyphasic approach to find characters that differentiate species and to establish accurate data on potential mycotoxin production by each species. Phylogenetic analysis of the ITS region, parts of the beta-tubulin and calmodulin genes, macro- and micromorphological examinations and analysis of extrolite profiles were applied. Phylogenetic analyses revealed that the genus Byssochlamys includes nine species, five of which form a teleomorph, i.e. B. fulva, B. lagunculariae, B. nivea, B. spectabilis and B. zollerniae, while four are asexual, namely P. brunneolus, P. divaricatus, P. formosus and P. saturatus. Among these, B. nivea produces the mycotoxins patulin and byssochlamic acid and the immunosuppressant mycophenolic acid. Byssochlamys lagunculariae produces byssochlamic acid and mycophenolic acid and thus chemically resembles B. nivea. Some strains of P. saturatus produce patulin and brefeldin A, while B. spectabilis (anamorph P. variotii s.s.) produces viriditoxin. Some micro- and macromorphological characters are valuable for identification purposes, including the shape and size of conidia and ascospores, presence and ornamentation of chlamydospores, growth rates on MEA and CYA and acid production on CREA. A dichotomous key is provided for species identification based on phenotypical characters.
PubMed: 20198134
DOI: 10.3767/003158509X418925 -
Survey of molds, yeast and Alicyclobacillus spp. from a concentrated apple juice productive process.Brazilian Journal of Microbiology :... 2014Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some...
Bacteria and molds may spoil and/or contaminate apple juice either by direct microbial action or indirectly by the uptake of metabolites as off-flavours and toxins. Some of these microorganisms and/or metabolites may remain in the food even after extensive procedures. This study aim to identify the presence of molds (including heat resistant species) and Alicyclobacillus spp., during concentrated apple juice processing. Molds were isolated at different steps and then identified by their macroscopic and microscopic characteristics after cultivation on standard media at 5, 25 and 37 °C, during 7 days. Among the 19 isolated found, 63% were identified as Penicillium with 50% belonging to the P. expansum specie. With regards to heat resistant molds, the species Neosartorya fischeri, Byssochlamys fulva and also the genus Eupenicillium sp., Talaromyces sp. and Eurotium sp. were isolated. The thermoacidophilic spore-forming bacteria were identified as A. acidoterrestris by a further investigation based on 16S rRNA sequence similarity. The large contamination found indicates the need for methods to eliminate or prevent the presence of these microorganisms in the processing plants in order to avoid both spoilage of apple juice and toxin production.
Topics: Alicyclobacillus; Bacterial Load; Beverages; Colony Count, Microbial; DNA, Bacterial; DNA, Ribosomal; Food Handling; Fungi; Malus; Microscopy; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 24948913
DOI: 10.1590/s1517-83822014000100008 -
Journal of Food Protection Jan 2011The mycotoxin, patulin (4-hydroxy-4H-furo[3,2c]pyran-2[6H]-one), is a secondary metabolite produced mainly in rotten parts of fruits and vegetables, most notably apples...
The mycotoxin, patulin (4-hydroxy-4H-furo[3,2c]pyran-2[6H]-one), is a secondary metabolite produced mainly in rotten parts of fruits and vegetables, most notably apples and apple products, by a wide range of fungal species in the genera Penicillium, Aspergillus, and Byssochlamys. Due to its mutagenic and teratogenic nature and possible health risks to consumers, many countries have regulations to reduce levels of patulin in apple products. In the present study, reduction of patulin contamination in apple juice by using 10 different inactivated yeast strains was assessed. Our results indicated that nearly twofold differences in biomass existed among the 10 yeast strains. Eight of the 10 inactivated yeast strains could provide >50% patulin reduction in apple juice within 24 h, with the highest reduction rate being >72%. Furthermore, juice quality parameters, i.e., degrees Brix, total sugar, titratable acidity, color value, and clarity, of the treated apple juice were very similar to those of the untreated patulin-free juice. Potential applications of using inactivated yeast strain for patulin control are also discussed.
Topics: Aspergillus; Beverages; Byssochlamys; Consumer Product Safety; Food Contamination; Humans; Malus; Mutagens; Patulin; Penicillium; Yeasts
PubMed: 21219779
DOI: 10.4315/0362-028X.JFP-10-326 -
Poultry Science Jan 2024Fungi are pathogens that infect all types of poultry and farmers, leading to economic losses in poultry production. Fungi can be isolated from environmental samples and...
Fungi are pathogens that infect all types of poultry and farmers, leading to economic losses in poultry production. Fungi can be isolated from environmental samples and are ubiquitous in the air. This study aimed to evaluate fungal contamination in domestic duck farm environments and analyze biosecurity risk factors associated with fungal infection incidence to assess the vulnerability of the farms to fungal infection. The average fungal concentration was 203 colony-forming units (CFU)/m in the air and 365 × 10 CFU/m in the wall surface samples. Sixteen fungal genera were recovered from air and wall surface samples from 19 duck-breeding farms, Aspergillus being the most frequently isolated (air: 43.2%; wall surface: 40%). Eleven additional fungal genera (Acrophialophora, Byssochlamys, Fusarium, Lichtheimia, Paecilomyces, Penicillium, Polycephalomyces, Rhizomucor, Scopulariopsis, Talaromyces, and Thermoascus) were isolated from air samples. Also, 8 additional fungal genera (Chaetomium, Lichtheimia, Penicillium, Petriella, Rhizomucor, Rhizopus, Talaromyces, and Trichosporon) were isolated from wall surface samples. The characteristics of the poultry farms (geographic region, stocking density, breeding house type, affiliate, duck age, and season) and fungal concentrations in the air and wall surface samples were analyzed to evaluate the biosecurity risk of the farms. Fungal infections were significantly affected by high stocking density (>2 ducks/m), duck age (18-25 wk and >60 wk), and high fungal concentration in the wall surface samples (>300 × 10 CFU/m).
Topics: Animals; Ducks; Farms; Biosecurity; Chickens; Plant Breeding; Poultry; Mycoses; Risk Factors
PubMed: 37925771
DOI: 10.1016/j.psj.2023.103197 -
Food Microbiology Dec 2019This study evaluated the effect of both gaseous and dissolved oxygen (O) concentration (0 - 21%) on the growth of six heat-resistant moulds (HRMs) (Neosartorya and...
This study evaluated the effect of both gaseous and dissolved oxygen (O) concentration (0 - 21%) on the growth of six heat-resistant moulds (HRMs) (Neosartorya and Byssochlamys spp.) previously isolated from high-acid fruit products. The study was performed in acidified potato dextrose agar (aPDA) with all six HRMs and with B. fulva and N. fischeri in strawberry, apple and orange juice-based media. At ≥ 0.15% O, visible growth of the HRMs occurred within 3-6 days. Complete inhibition on aPDA did not occur even at very low levels of dissolved O (ca. 0.01% O). With the exception of B. fulva, decrease of the O concentration to ≤0.03% resulted in significantly (p < 0.05) longer times to visible growth. The growth of N. laciniosa, N. fischeri, B. nivea and B. fulva was inhibited for 30 days when they were incubated under strict anaerobic conditions. As in aPDA, B. fulva and N. fischeri grew in the three fruit-based media at O concentrations ≥0.15%. Significantly slower (p < 0.05) growth was observed for N. fischeri in orange juice medium. Strategies to inhibit the growth of HRMs should therefore not be based entirely on establishing low headspace O levels. With this in mind, the effect of low O concentrations (<1%) should be studied in combination with other factors (hurdles) such as antioxidants, organic acids, sugars (a), storage temperature and pasteurization intensity, in order to predict the growth inhibition of the HRMs.
Topics: Anaerobiosis; Culture Media; Food Microbiology; Fruit and Vegetable Juices; Fungi; Hot Temperature; Oxygen; Spores, Fungal
PubMed: 31421750
DOI: 10.1016/j.fm.2019.103243 -
Applied Microbiology and Biotechnology Feb 2015The filamentous fungus Paecilomyces variotii NBRC 109023 (teleomorph: Byssochlamys spectabilis NBRC 109023) degrades formaldehyde at concentrations as high as 2.4 %...
The filamentous fungus Paecilomyces variotii NBRC 109023 (teleomorph: Byssochlamys spectabilis NBRC 109023) degrades formaldehyde at concentrations as high as 2.4 % (w/v). In many prokaryotes and in all known eukaryotes, formaldehyde degradation is catalyzed by S-hydroxymethylglutathione (S-HMGSH) dehydrogenase. We report here the isolation and characterization of the gene encoding S-HMGSH dehydrogenase activity in P. variotii. The 1.6-kb fldA gene contained 5 introns and 6 exons, and the corresponding cDNA was 1143 bp, encoding a 40-kDa protein composed of 380 amino acids. FldA was predicted to have 74.3, 73.7, 68.5, and 67.4 % amino acid identity to the S-HMGSH dehydrogenases of Hansenula polymorpha, Candida boidinii, Saccharomyces cerevisiae, and Kluyveromyces lactis, respectively. The predicted protein also showed high amino acid similarity (84∼86 %) to the products of putative fldA genes from other filamentous fungi, including Aspergillus sp. and Penicillium sp. Notably, the P. variotii fldA gene was able to functionally complement a Saccharomyces cerevisiae strain (BY4741 ∆sfa1) lacking the gene for S-HMGSH dehydrogenase. The heterologous expression construct rendered BY4741 ∆sfa1 tolerant to exogenous formaldehyde. Although BY4741 (parental wild-type strain) was unable to degrade even low concentrations of formaldehyde, BY4741 ∆sfa1 harboring Paecilomyces fldA was able to degrade 4 mM formaldehyde within 30 h. The findings from this study confirm the essential role of S-HMGSH dehydrogenase in detoxifying formaldehyde.
Topics: Biotransformation; Cloning, Molecular; DNA, Complementary; DNA, Fungal; Exons; Formaldehyde; Gene Expression; Genetic Complementation Test; Glutathione; Introns; Molecular Sequence Data; Molecular Weight; Oxidoreductases; Paecilomyces; Recombinant Proteins; Sequence Analysis, DNA; Sequence Homology, Amino Acid
PubMed: 25398285
DOI: 10.1007/s00253-014-6203-8 -
Journal of Food Protection Apr 1989A variety of citrus products, including dried peel used as livestock fodder, unpasteurized orange juice and pasteurized, and chilled orange juice were selectively...
A variety of citrus products, including dried peel used as livestock fodder, unpasteurized orange juice and pasteurized, and chilled orange juice were selectively surveyed for their fungal microflora. Fungi isolated were 1) pasteurized orange juice: Aureobasidium pullulans , Cladosporium sp., and Penicillium sp., 2) unpasteurized orange juice: Candida maltosa , C. sake , Fusarium sp., Geotrichum sp., Hanseniaspora sp., H. guilliermondii , Penicillium sp., Pichia membranaefaciens , Saccharomyces cerevisiae , Schwanniomyces occidentalis , and Torulaspora delbrueckii and 3) dried peel: Aspergillus niger , Aspergillus sp., Byssochlamys sp., Fusarium sp., Penicillium sp., Rhizopus sp., Rhodotorula sp., Sc. occidentalis , and Trichoderma sp.
PubMed: 30991523
DOI: 10.4315/0362-028X-52.4.261 -
Journal of Food Protection Aug 2010Heat-resistant fungi, genera Byssochlamys, Talaromyces, Neosartorya, and Hamigera, contribute significantly to the spoilage of heat-processed acidic foods, due to the...
Heat-resistant fungi, genera Byssochlamys, Talaromyces, Neosartorya, and Hamigera, contribute significantly to the spoilage of heat-processed acidic foods, due to the formation of heat-resistant ascospores. Here, we first evaluated the differences in the beta-tubulin gene between Byssochlamys and Hamigera and developed specific primers to identify the Byssochlamys species fulva, nivea, and spectabilis, and Hamigera. Using primers designed for B. fulva and B. nivea (B1F/1R), specific PCR products were detected for B. fulva and B. nivea, as well as B. langunculariae and B. zollerniae, two closely related species. Similarly, the Pae4F/4R-1 and H2F/2R primers produced specific PCR products for B. spectabilis and Hamigera, respectively. Using these three primer sets, strains involved in acidic food spoilage and environmental contamination were not detected. The detection limits of all primer sets were 1 ng of DNA by PCR and 10 pg of DNA by nested PCR. Each PCR assay was specific, even if the sample was contaminated 1,000-fold by other fungal DNA. Thus, this method has proved to possess an extremely high degree of specificity.
Topics: Byssochlamys; DNA Primers; DNA, Fungal; Eurotiales; Food Contamination; Food Microbiology; Molecular Sequence Data; Neosartorya; Polymerase Chain Reaction; Sequence Alignment; Species Specificity; Spores, Fungal; Talaromyces; Tubulin
PubMed: 20819359
DOI: 10.4315/0362-028x-73.8.1486