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Food Microbiology Aug 2019Fungi are able to grow on diverse food products and contribute to food spoilage worldwide causing food loss. Consumers prefer freshly squeezed fruit juices, however, the...
Fungi are able to grow on diverse food products and contribute to food spoilage worldwide causing food loss. Consumers prefer freshly squeezed fruit juices, however, the shelf life of these juices is limited due to outgrowth of yeast and fungi. The shelf life of pulsed electric field (PEF) treated juice can be extended from 8 days up to a few weeks before spoilage by moulds becomes apparent. Conidia produced by three Penicillium ssp. (Penicillium expansum, Penicillium buchwaldii and Penicillium bialowiezense), previously isolated from spoiled PEF treated fruit juice and smoothie, were characterized for resistance towards selected mild physical processing techniques in orange juice and toward sanitizers on surfaces. The results show that Penicillium spp. conidia are susceptible to mild heat, high pressure pasteurization (HPP), PEF, cold atmospheric plasma (CAP), UV, and chemical sanitizers chlorine dioxide and hypochlorite albeit with different susceptibility. Treatment with mild heat, HPP, PEF, or chlorine dioxide reduced conidia by more than 5 log. For hypochlorite, UV, and CAP the reduction was between 1 and 3 log. Together, this study provides data for the development of intervention strategies to eliminate spoilage mould conidia in fruit juices.
Topics: Chlorine Compounds; Citrus sinensis; Disinfection; Electricity; Food Handling; Food Preservation; Food Storage; Fruit and Vegetable Juices; Hot Temperature; Hypochlorous Acid; Microbial Sensitivity Tests; Oxides; Pasteurization; Penicillium; Plasma Gases; Spores, Fungal; Ultraviolet Rays
PubMed: 30910081
DOI: 10.1016/j.fm.2018.06.004 -
Environmental Microbiology Jun 2019To date, no demonstration of a direct correlation between the presence of mycoviruses and the quantitative or qualitative modulation of mycotoxins has been shown. In our...
To date, no demonstration of a direct correlation between the presence of mycoviruses and the quantitative or qualitative modulation of mycotoxins has been shown. In our study, we transfected a virus-free ochratoxin A (OTA)-producing isolate of Aspergillus ochraceus with purified mycoviruses from a different A. ochraceus isolate and from Penicillium aurantiogriseum. Among the mycoviruses tested, only Aspergillus ochraceus virus (AoV), a partitivirus widespread in A. ochraceus, caused a specific interaction that led to an overproduction of OTA, which is regulated by the European Commission and is the second most important contaminant of food and feed commodities. Gene expression analysis failed to reveal a specific viral upregulation of the mRNA of genes considered to play a role in the OTA biosynthetic pathway. Furthermore, AoOTApks1, a polyketide synthase gene considered essential for OTA production, is surprisingly absent in the genome of our OTA-producing isolate. The possible biological and evolutionary implications of the mycoviral regulation of mycotoxin production are discussed.
Topics: Aspergillus ochraceus; Biosynthetic Pathways; Fungal Proteins; Fungal Viruses; Ochratoxins; Penicillium; Polyketide Synthases
PubMed: 30289193
DOI: 10.1111/1462-2920.14436 -
Toxins Aug 2021is an important postharvest pathogen of pomaceous fruit and a causal agent of blue mold or soft rot. In this study, we investigated the effect of ambient pH on growth,...
is an important postharvest pathogen of pomaceous fruit and a causal agent of blue mold or soft rot. In this study, we investigated the effect of ambient pH on growth, ultrastructure alteration, and pathogenicity of , as well as accumulation of patulin and expression of genes involved in patulin biosynthesis. Under different pH, the fungus was routinely cultured and collected for growth, pathogenicity, patulin production, and gene expression studies using transmission electron microscopy, apple inoculation, HPLC, and RT-qPCR methods. Different ambient pH had significant impact on expression of genes and growth factors involved in patulin biosynthesis. Under same range of pH, gene expression profile, growth factors, and patulin accumulation (in vivo and in vitro) all showed similar changing trends. A well-developed cell was observed in addition to upregulation of genes at pH between pH 5.0 and 7.0, while the opposite was observed when pH was too basic (8.5) or too acid (2.5). Additionally, ambient pH had direct or indirect influence on expression of , and . These findings will help in understanding the effect of ambient pH on growth, pathogenicity, and patulin production and support the development of successful methods for combating infection on apple fruits.
Topics: Biomass; Fruit; Gene Expression Regulation, Fungal; Germination; Hydrogen-Ion Concentration; Malus; Microscopy, Electron, Transmission; Patulin; Penicillium
PubMed: 34437421
DOI: 10.3390/toxins13080550 -
Organic Letters Aug 2020Quinolone-containing natural products are widely found in bacteria, fungi, and plants. The fungal quinolactacins, which are methyl-4-quinolones, display a wide spectrum...
Quinolone-containing natural products are widely found in bacteria, fungi, and plants. The fungal quinolactacins, which are methyl-4-quinolones, display a wide spectrum of biological activities. Here we uncovered a concise nonribosomal peptide synthetase pathway involved in quinolactacin A biosynthesis from by using heterologous reconstitution and enzymatic synthesis. The desmethyl analog of quinolactacin A was accessed through the construction of a hybrid bacterial and fungi pathway in the heterologous host.
Topics: 4-Quinolones; Biological Products; Fungi; Molecular Structure; Penicillium; Peptide Synthases; Quinolones
PubMed: 32806159
DOI: 10.1021/acs.orglett.0c02426 -
Journal of Applied Microbiology Nov 2016This study was conducted to evaluate the biocontrol potential of Bacillus subtilis CICC 10034, Rhodobacter sphaeroides CGMCC 1.2182 and Agrobacterium tumefaciens CGMCC...
AIMS
This study was conducted to evaluate the biocontrol potential of Bacillus subtilis CICC 10034, Rhodobacter sphaeroides CGMCC 1.2182 and Agrobacterium tumefaciens CGMCC 1.2554 against patulin (PAT)-producer Penicillium expansum and their ability to remove PAT.
METHODS AND RESULTS
Bacillus subtilis effectively inhibited P. expansum both on apples and in in vitro experiments, which reduced the rot diameter on apples by 38% compared with the control. The reduction was followed by those induced by A. tumefaciens (27·63%) and R. sphaeroides (23·67%). None of the cell-free supernatant (CFS) was able to prevent pathogen growth. Three antagonists could suppress PAT production by P. expansum on apples by 98·5, 93·7 and 94·99% after treatment with B. subtilis, R. sphaeroides and A. tumefaciens respectively. In addition, the three strains led to a 0·56-1·47 log CFU g reduction in colony number of P. expansum on apples. Survival of antagonists on apple wounds revealed their tolerance to PAT. Furthermore, both live and autoclaved cells of three strains efficiently adsorbed artificially spiked PAT from medium.
CONCLUSIONS
The selected antagonists could be applied before harvesting to control apple infection by PAT-producing fungi and also during processing to act as PAT detoxifiers.
SIGNIFICANCE AND IMPACT OF THE STUDY
Since little information related to the capability of R. sphaeroides and A. tumefaciens to inhibit P. expansum is currently available, the results of this study provide some new perspectives to the biocontrol field.
Topics: Agrobacterium tumefaciens; Bacillus subtilis; Biological Control Agents; Fruit; Malus; Patulin; Penicillium; Rhodobacter sphaeroides
PubMed: 27328641
DOI: 10.1111/jam.13208 -
Journal of Food Protection Feb 2001Several strains of Penicillium are used for the production of mold-ripened cheeses, and some of them are able to produce mycotoxins. The aims of the research were the...
Several strains of Penicillium are used for the production of mold-ripened cheeses, and some of them are able to produce mycotoxins. The aims of the research were the determination of roquefortine C and PR toxin in domestic and imported blue cheeses, the identification of the penicillia used as starter, and the investigation of their capacity for producing toxins in culture media. Roquefortine C was always found in the cheeses at levels ranging from 0.05 to 1.47 mg/kg, whereas the PR toxin was never found. The identification of the fungal strains present in the domestic cheeses included Penicillium glabrum, Penicillium roqueforti, and Penicillium cyclopium in the Gorgonzola "dolce" and Penicillium roqueforti in the Gorgonzola "naturale"; in one case, the presence of Penicillium crustosum was observed. The strains isolated from the foreign cheeses belonged to P. roqueforti. The strains were able to produce between 0.18 and 8.44 mg/liter of roquefortine in yeast extract sucrose medium and between 0.06 and 3.08 mg/liter and less than 0.05 mg/liter when inoculated in milk at 20 degrees C for 14 days and 4 degrees C for 24 days, respectively. Linear relations between production of roquefortine in culture media and cheeses did not emerge. PR toxin ranged from less than 0.05 to 60.30 mg/liter in yeast extract sucrose medium and was produced in milk at 20 degrees C from only one strain. The low levels and the relatively low toxicity of roquefortine make the consumption of blue cheese safe for the consumer.
Topics: Cheese; Chromatography, High Pressure Liquid; Ergolines; Heterocyclic Compounds, 4 or More Rings; Indoles; Mycotoxins; Naphthols; Penicillium; Piperazines; Time Factors
PubMed: 11271775
DOI: 10.4315/0362-028x-64.2.246 -
Food Microbiology Aug 2018Penicillium and Aspergillus genera, both including mycotoxin producing species, were reported as associated to cheese and cheese working environment, but never studied...
Penicillium and Aspergillus genera, both including mycotoxin producing species, were reported as associated to cheese and cheese working environment, but never studied in an extensive way in Italian grana cheese (Grana Padano and Parmigiano Reggiano). The aim of this work was to address the identification of Aspergilli and Penicillia associated to grana cheese in order to lay down the basis for risk assessment and safe processing for a high quality production. One hundred and four strains belonging to Aspergillus and Penicillium genera were obtained from cheese crust and from ripening room air (with the latter largely dominant), and identified following a polyphasic approach, strongly required for the identification at the species level. Morphological observation was used along with molecular techniques, RAPD-PCR fingerprinting and calmodulin gene sequencing (CaM), the former aimed to limit as much as possible the latter sequencing effort. Seventy four percent of the strains were assigned to Penicillium subgenus Penicillium, section Fasciculata. Main mycotoxin producing species identified were A. flavus, P. crustosum and P. verrucosum, while the dominant species in both air and cheese crust was P. solitum, which has never been so far reported as mycotoxigenic. Results obtained in this study confirmed that mycotoxin contamination is a possible issue to face during grana cheese making.
Topics: Aspergillus; Cheese; Food Contamination; Italy; Mycotoxins; Penicillium; Random Amplified Polymorphic DNA Technique
PubMed: 29526199
DOI: 10.1016/j.fm.2018.01.012 -
Journal of Microbiological Methods Dec 2015Mold growth constitutes a problem in many food and clinical environments and there is therefore focus on studying antifungal activity. Methods for determining growth...
Mold growth constitutes a problem in many food and clinical environments and there is therefore focus on studying antifungal activity. Methods for determining growth inhibition by measuring colony growth or biomass are, however, time-taking and rapid methods for evaluation of antifungal effects are needed. Propionic acid and diacetyl are antifungal compounds produced by a range of dairy-associated bacteria. Their activity against Penicillium spp. was monitored real-time using an optical detection system with tilted focus plane to assess growth and morphological changes of Penicillium spp. by image recording inside a 96 well microplate. Images were used for generation of growth curves by using a segmentation and extraction of surface areas (SESA) algorithm and for quantifying morphology changes. Using image analysis growth could be detected within 15 h compared with more than 30 h when using standard optical density measurements. Induced morphological changes of fungi could furthermore be visualized and quantified using morphological descriptors such as circularity, branch points, perimeter and area of spores and growing hyphae. Propionic acid inhibited two out of two Penicillium spp. while morphological changes were strain dependent at the concentrations tested. Diacetyl inhibited six out of six Penicillium spp. strains and increased spore size and number of germination sites in two out of six of the strains prior to germination.
Topics: Antifungal Agents; Diacetyl; Penicillium; Propionates; Spores, Fungal
PubMed: 26541062
DOI: 10.1016/j.mimet.2015.10.024 -
PloS One 2015Penicillium digitatum is the most destructive postharvest pathogen of citrus fruits, causing fruit decay and economic loss. Additionally, control of the disease is...
A novel sterol regulatory element-binding protein gene (sreA) identified in penicillium digitatum is required for prochloraz resistance, full virulence and erg11 (cyp51) regulation.
Penicillium digitatum is the most destructive postharvest pathogen of citrus fruits, causing fruit decay and economic loss. Additionally, control of the disease is further complicated by the emergence of drug-resistant strains due to the extensive use of triazole antifungal drugs. In this work, an orthologus gene encoding a putative sterol regulatory element-binding protein (SREBP) was identified in the genome of P. digitatum and named sreA. The putative SreA protein contains a conserved domain of unknown function (DUF2014) at its carboxyl terminus and a helix-loop-helix (HLH) leucine zipper DNA binding domain at its amino terminus, domains that are functionally associated with SREBP transcription factors. The deletion of sreA (ΔsreA) in a prochloraz-resistant strain (PdHS-F6) by Agrobacterium tumefaciens-mediated transformation led to increased susceptibility to prochloraz and a significantly lower EC50 value compared with the HS-F6 wild-type or complementation strain (COsreA). A virulence assay showed that the ΔsreA strain was defective in virulence towards citrus fruits, while the complementation of sreA could restore the virulence to a large extent. Further analysis by quantitative real-time PCR demonstrated that prochloraz-induced expression of cyp51A and cyp51B in PdHS-F6 was completely abolished in the ΔsreA strain. These results demonstrate that sreA is a critical transcription factor gene required for prochloraz resistance and full virulence in P. digitatum and is involved in the regulation of cyp51 expression.
Topics: Amino Acid Sequence; Citrus; Drug Resistance, Fungal; Fungal Proteins; Fungicides, Industrial; Gene Expression Regulation, Fungal; Genes, Fungal; Imidazoles; Molecular Sequence Data; Penicillium; Plant Diseases; Sequence Analysis, DNA; Sterol 14-Demethylase; Sterol Regulatory Element Binding Proteins; Transcription, Genetic; Virulence
PubMed: 25699519
DOI: 10.1371/journal.pone.0117115 -
Applied and Environmental Microbiology Feb 1987The taxonomy of the important mycotoxigenic species Penicillium viridicatum and P. verrucosum was reviewed to clarify disagreements relating to the three P. viridicatum...
The taxonomy of the important mycotoxigenic species Penicillium viridicatum and P. verrucosum was reviewed to clarify disagreements relating to the three P. viridicatum groups erected by Ciegler and coworkers (A. Ciegler, D. I. Fennell, G. A. Sansing, R. W. Detroy, and G. A. Bennett, Appl. Microbiol. 26:271-278, 1973) and the mycotoxins produced by them. Cultures derived from the types of these two species and authentic cultures from each group and from many other sources were examined culturally, microscopically, and for mycotoxin production. It was concluded that P. viridicatum group II has affinities with P. verrucosum and not with P. viridicatum, as indicated by J. I. Pitt in the 1979 monograph (The Genus Penicillium and Its Teleomorphic States Eupenicillium and Talaromyces). As a result of this study it can now be unequivocally stated that the mycotoxins ochratoxin A and citrinin are not produced by P. viridicatum. Of species in subgenus Penicillium, only P. verrucosum is known to produce ochratoxin A.
Topics: Culture Media; Mycotoxins; Ochratoxins; Penicillium; Species Specificity
PubMed: 3566267
DOI: 10.1128/aem.53.2.266-269.1987