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Journal of Dairy Science Nov 2002Color formation, metabolite production and growth of Penicillium caseifulvum were studied in order to elucidate factors contributing to yellow discoloration of Blue...
Color formation, metabolite production and growth of Penicillium caseifulvum were studied in order to elucidate factors contributing to yellow discoloration of Blue Cheese caused by the mold. A screening experiment was set up to study the effect of pH, concentration of salt (NaCl), P, K, N, S, Mg and the trace metals Fe, Cu, Zn, Mn on yellow color formation, metabolite production and mold growth. Multivariate statistical analysis showed that the most important factor affecting yellow color formation was pH. The most pronounced formation of yellow color, supported by highest amount of colored metabolites, appeared at low pH (pH 4). Mold growth was not correlated to the yellow color formation. Salt concentration was the most important factor affecting mold growth and length of lag phase. Production of secondary metabolites was strongly influenced by both pH and salt concentration. The screening results were used to divide the metabolites into the following three groups: 1) correlated to growth, 2) correlated to color formation, and 3) formed at high pH. Subsequently, a full factorial experiment with factors P, Mg and Cu, showed that low P concentrations (2,000 mg/kg) induced yellow color formation. Among the factors contributing to yellow color formation, pH and salt concentration are easy to control for the cheesemaker, while the third factor, P-concentration, is not. Naturally occurring variations in the P-concentration in milk delivered to Blue Cheese plants, could be responsible for the yellow discoloration phenomenon observed in the dairy industry.
Topics: Cheese; Food Microbiology; Hydrogen-Ion Concentration; Minerals; Penicillium; Phosphorus; Pigmentation; Sodium Chloride
PubMed: 12487445
DOI: 10.3168/jds.S0022-0302(02)74365-8 -
Nature Communications Jan 2018Non-heme iron and α-ketoglutarate (αKG) oxygenases catalyze remarkably diverse reactions using a single ferrous ion cofactor. A major challenge in studying this...
Non-heme iron and α-ketoglutarate (αKG) oxygenases catalyze remarkably diverse reactions using a single ferrous ion cofactor. A major challenge in studying this versatile family of enzymes is to understand their structure-function relationship. AusE from Aspergillus nidulans and PrhA from Penicillium brasilianum are two highly homologous Fe(II)/αKG oxygenases in fungal meroterpenoid biosynthetic pathways that use preaustinoid A1 as a common substrate to catalyze divergent rearrangement reactions to form the spiro-lactone in austinol and cycloheptadiene moiety in paraherquonin, respectively. Herein, we report the comparative structural study of AusE and PrhA, which led to the identification of three key active site residues that control their reactivity. Structure-guided mutagenesis of these residues results in successful interconversion of AusE and PrhA functions as well as generation of the PrhA double and triple mutants with expanded catalytic repertoire. Manipulation of the multifunctional Fe(II)/αKG oxygenases thus provides an excellent platform for the future development of biocatalysts.
Topics: Aspergillus nidulans; Catalytic Domain; Ketoglutaric Acids; Mixed Function Oxygenases; Nonheme Iron Proteins; Oxidation-Reduction; Penicillium; Structure-Activity Relationship; Substrate Specificity; Terpenes
PubMed: 29317628
DOI: 10.1038/s41467-017-02371-w -
Extremophiles : Life Under Extreme... Sep 2016Mycobiota are important in underground ecology. In 2014, we discovered dark stains on clayey sediments on the walls of Driny Cave, Slovakia. Our description is based on...
Mycobiota are important in underground ecology. In 2014, we discovered dark stains on clayey sediments on the walls of Driny Cave, Slovakia. Our description is based on the morphology of the fungus and the phylogenetic relationships of the internal transcribed spacer (ITS) region. In addition, data on its capacity for the production of extracellular enzymes, growth, and survival in vitro at different temperatures are reported. Our analyses revealed that this dark stains on the wall was produced by Penicillium glandicola. The fungus was able to synthesize amylases, proteases and cellulases, but not pectinases and keratinases. The vegetative structures of mycelium of this fungus are viable in vitro after storage at cool temperatures (from -72 to 5 °C), and show active growth at temperatures from 5 to 25 °C, but without spore germination, and without active growth at 30 and 37 °C. Penicillium glandicola is a psychrotolerant species and belong to var. glandicola.
Topics: Acclimatization; Caves; Cold Temperature; DNA, Intergenic; Fungal Proteins; Geologic Sediments; Microbiota; Penicillium
PubMed: 27315167
DOI: 10.1007/s00792-016-0853-7 -
Microbial Cell Factories Dec 2022Raw starch-degrading enzyme (RSDE) is applied in biorefining of starch to produce biofuels efficiently and economically. At present, RSDE is obtained via secretion by...
BACKGROUND
Raw starch-degrading enzyme (RSDE) is applied in biorefining of starch to produce biofuels efficiently and economically. At present, RSDE is obtained via secretion by filamentous fungi such as Penicillium oxalicum. However, high production cost is a barrier to large-scale industrial application. Genetic engineering is a potentially efficient approach for improving production of RSDE. In this study, we combined genetic engineering and random mutagenesis of P. oxalicum to enhance RSDE production.
RESULTS
A total of 3619 mutated P. oxalicum colonies were isolated after six rounds of ethyl methanesulfonate and Co-γ-ray mutagenesis with the strain A2-13 as the parent strain. Mutant TE4-10 achieved the highest RSDE production of 218.6 ± 3.8 U/mL with raw cassava flour as substrate, a 23.2% compared with A2-13. Simultaneous deletion of transcription repressor gene PoxCxrC and overexpression of activator gene PoxAmyR in TE4-10 resulted in engineered strain GXUR001 with an RSDE yield of 252.6 U/mL, an increase of 15.6% relative to TE4-10. Comparative transcriptomics and real-time quantitative reverse transcription PCR revealed that transcriptional levels of major amylase genes, including raw starch-degrading glucoamylase gene PoxGA15A, were markedly increased in GXUR001. The hydrolysis efficiency of raw flour from cassava and corn by crude RSDE of GXUR001 reached 93.0% and 100%, respectively, after 120 h and 84 h with loading of 150 g/L of corresponding substrate.
CONCLUSIONS
Combining genetic engineering and random mutagenesis efficiently enhanced production of RSDE by P. oxalicum. The RSDE-hyperproducing mutant GXUR001 was generated, and its crude RSDE could efficiently degrade raw starch. This strain has great potential for enzyme preparation and further genetic engineering.
Topics: Starch; Penicillium; Genetic Engineering; Mutagenesis
PubMed: 36566178
DOI: 10.1186/s12934-022-01997-w -
Journal of Clinical Microbiology Jan 1995The phylogenetic position of the human pathogenic fungus Penicillium marneffei was assessed from the nucleotide sequences of the nuclear and mitochondrial ribosomal DNA...
The phylogenetic position of the human pathogenic fungus Penicillium marneffei was assessed from the nucleotide sequences of the nuclear and mitochondrial ribosomal DNA regions. Phylogenetic analysis determined that P. marneffei is closely related to species of Penicillium subgenus Biverticillium and sexual Talaromyces species with asexual biverticillate Penicillium states. Knowledge of the phylogenetic position of P. marneffei facilitated the design of unique oligonucleotide primers, from the nuclear ribosomal DNA internal transcribed spacer region, for the specific amplification of P. marneffei DNA. These primers were successful at selectively amplifying DNA from six isolates of P. marneffei and excluding the other species tested, which included Penicillium subgenus Biverticillium and Talaromyces species and several well-known fungal pathogens, namely, Aspergillus fumigatus, Coccidioides immitis, Histoplasma capsulatum, and Pneumocystis carinii. The primers that we have developed for the specific amplification of P. marneffei have the potential to be incorporated in a PCR identification system which could be used for the identification of this pathogenic agent from clinical material.
Topics: Animals; Base Sequence; DNA Primers; DNA, Mitochondrial; DNA, Ribosomal; Deoxyribonucleases, Type II Site-Specific; Humans; Molecular Sequence Data; Mycoses; Penicillium; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 5.8S
PubMed: 7699073
DOI: 10.1128/jcm.33.1.85-89.1995 -
MicrobiologyOpen Jun 2018In this study, Penicillium expansum, a common destructive phytopathogen and patulin producer was isolated from naturally infected apple fruits and identified by...
In this study, Penicillium expansum, a common destructive phytopathogen and patulin producer was isolated from naturally infected apple fruits and identified by morphological observation and rDNA-internal transcribed spacer analysis. Subsequently, a global view of the transcriptome and proteome alteration of P. expansum spores during germination was evaluated by RNA-seq (RNA sequencing) and iTRAQ (isobaric tags for relative and absolute quantitation) approaches. A total of 3,026 differentially expressed genes (DEGs), 77 differentially expressed predicted transcription factors and 489 differentially expressed proteins (DEPs) were identified. The next step involved screening out 130 overlapped candidates through correlation analysis between the RNA-seq and iTRAQ datasets. Part of them showed a different expression trend in the mRNA and protein levels, and most of them were involved in metabolism and genetic information processing. These results not only highlighted a set of genes and proteins that were important in deciphering the molecular processes of P. expansum germination but also laid the foundation to develop effective control methods and adequate environmental conditions.
Topics: DNA, Fungal; DNA, Ribosomal; DNA, Ribosomal Spacer; Fruit; Gene Expression Profiling; Malus; Microscopy; Penicillium; Proteome; Sequence Analysis, DNA; Spores, Bacterial
PubMed: 29205951
DOI: 10.1002/mbo3.562 -
Fungal Genetics and Biology : FG & B Nov 2019The importance of the metabolic route of nitrogen in the fungus Penicillium rubens (strain PO212) is studied in relation to its biocontrol activity (BA). PO212 can...
The importance of the metabolic route of nitrogen in the fungus Penicillium rubens (strain PO212) is studied in relation to its biocontrol activity (BA). PO212 can resist a high concentration of chlorate anion and displays a classical nitrate-deficiency (nit-) phenotype resulting in poor colonial growth when nitrate is used as the main source of nitrogen. Analyses of genes implicated in nitrate assimilation evidenced the strong sequence conservation of PO212 and CH8 genome with penicillin producers such as reference strain P. rubens Wisconsin 54-1255, P2niaD18 and Pc3, however also revealed the presence of mutations. PO212 carries a mutation in the gene coding for zinc-binuclear cluster transcription factor NirA that specifically mediates the regulation of genes involved in nitrate assimilation. The nirA1 mutation causes an early stop of NirA factor, losing 66% of its sequence. The NirA1 mutant form is unable to mediate a nitrate-dependent regulation of nitrate and nitrite reductase coding genes. In this study, we study another isolate, CH8, with potential BA and nit- phenotype. A mutation in the nitrate permease coding gene crnA was found in CH8. An insertion of a guanine in the coding sequence cause a frameshift in CrnA with the loss of the last two transmembrane domains. Analysis of PO212 and CH8 isolates and complementation strains show the importance of NirA regulator in maintaining correct transcriptional levels of nitrate and nitrite reductases and suggest CrnA as the main nitrate transporter. the presence of alternative transporter for chlorate and the existence of a mechanism for preventing nitrite derived toxicity in Penicillum. BA of PO212 is partially altered when nirA1 mutation was complemented. This result and the finding of CH8, a novel biocontrol P. rubens strain with a nit- phenotype, suggest that nitrogen metabolism is a component of biocontrol capacity.
Topics: Anion Transport Proteins; Biological Control Agents; Chlorates; Gene Expression Regulation, Fungal; Solanum lycopersicum; Mutation; Nitrate Transporters; Nitrates; Nitrite Reductases; Nitrogen; Penicillium; Phenotype; Plant Diseases; Transcription Factors
PubMed: 31419528
DOI: 10.1016/j.fgb.2019.103263 -
Research in Microbiology Mar 2008Based on bioinformatic data on model fungi, the rodA and wetA genes encoding, respectively, a RodA hydrophobin protein and the WetA protein involved in conidiation...
Based on bioinformatic data on model fungi, the rodA and wetA genes encoding, respectively, a RodA hydrophobin protein and the WetA protein involved in conidiation mechanisms, were PCR-cloned and characterized for the first time in Penicillium camemberti. These results, completed by a sequence of the brlA gene (available in GenBank), which encodes a major transcriptional regulator also involved in the conidiation mechanism, were used to compare, by qRT-PCR, the expression of the three genes in liquid and solid cultures in a synthetic medium. While expression of the brlA and wetA genes increased dramatically in both culture conditions after 4 days of growth, expression of the rodA gene increased only with conidiation and in the solid culture, and this expression was correlated with production and secretion of a RodA protein outside the hyphae, which became very hydrophobic. In liquid cultures, no production of RodA occurred in mycelia, which remained hydrophilic, and no conidiation was detected despite formation of swellings at the tips of hyphae. The absence of conidiation in liquid culture correlated with the lack of rodA gene expression, which could be regulated by the medium composition independently of brlA and wetA genes expression.
Topics: Amino Acid Sequence; Base Sequence; Cloning, Molecular; Culture Media; Fungal Proteins; Gene Expression Regulation, Fungal; Hydrophobic and Hydrophilic Interactions; Molecular Sequence Data; Mycelium; Penicillium; Sequence Alignment; Sequence Analysis, DNA; Spores, Fungal
PubMed: 18093806
DOI: 10.1016/j.resmic.2007.10.004 -
Applied and Environmental Microbiology Feb 1977Four of the metabolites of Penicillium viridicatum 66-68-2 grown on rice cultures were isolated and identified as xanthomegnin, viomellein, rubrosulphin, and...
Four of the metabolites of Penicillium viridicatum 66-68-2 grown on rice cultures were isolated and identified as xanthomegnin, viomellein, rubrosulphin, and viopurpurin. Melting points, elemental analysis, and infrared, ultraviolet, and field desorption and electron impact mass spectra of the isolated compounds were consistent with values reported in the literature for these compounds. In addition, diacetate and triacetate derivatives were prepared, and the chemical and physical analyses of the derivatives were also consistent with literature data. Proton magnetic resonance spectroscopy and thin-layer chromatography were also used for the additional identification of selected compounds.
Topics: Chemical Phenomena; Chemistry; Mycotoxins; Penicillium
PubMed: 848956
DOI: 10.1128/aem.33.2.351-355.1977 -
International Journal of Food... Aug 2024The study prepared and used eugenol nanoemulsion loaded with nobiletin as fungistat to study its antifungal activity and potential mechanism of Penicillium italicum (P....
The study prepared and used eugenol nanoemulsion loaded with nobiletin as fungistat to study its antifungal activity and potential mechanism of Penicillium italicum (P. italicum). The results showed that the minimum inhibitory concentration (MIC) of eugenol nanoemulsion loaded with nobiletin (EGN) was lower than that of pure eugenol nanoemulsion (EG), which were 160 μg/mL and 320 μg/mL, respectively. At the same time, the mycelial growth inhibition rate of EGN nanoemulsion (54.68 %) was also higher than that of EG nanoemulsion (9.92 %). This indicates that EGN nanoemulsion is more effective than EG nanoemulsion. Compared with EG nanoemulsion, the treatment of EGN nanoemulsion caused more serious damage to the cell structure of P. italicum. At the same time, in vitro inoculation experiments found that EGN nanoemulsion has better control and delay the growth and reproduction of P. italicum in citrus fruits. And the results reflected that EGN nanoemulsion may be considered as potential resouces of natural antiseptic to inhibit blue mold disease of citrus fruits, because it has good antifungal activity.
Topics: Penicillium; Eugenol; Antifungal Agents; Emulsions; Flavones; Citrus; Microbial Sensitivity Tests; Nanoparticles
PubMed: 38823189
DOI: 10.1016/j.ijfoodmicro.2024.110769