Biomedical subjects

J C Frisvad

Publications and source records attributed to J C Frisvad.

At least 19 recordsLinked to original sources

PubMed2006

Host-derived media used as a predictor for low abundant, in planta metabolite production from necrotrophic fungi.

AIMS: Penicillium ser. Corymbifera strains were assayed on a variety of media and from infected Allium cepa tissues to evaluate the stimulation and in planta prediction of low abundance metabolites. METHODS AND RESULTS: Stimulated production of corymbiferones and the corymbiferan lactones were observed for Penicillium albocoremium, Penicillium allii, Penicillium hirsutum, Penicillium hordei and Penicillium venetum strains cultured on tissue media. Target metabolites were sporadically detected from strains cultured on common laboratory media (CYA, MEA and YES). Up to a 376 times increase in corymbiferone and corymbiferan lactone production was observed when culture extracts from CYA and A. cepa agar were compared by high pressure liquid chromatography with ultraviolet and mass spectrometry (LC-UV-MS). The novel metabolite corymbiferone B was purified and structure elucidated from a P. allii/A. cepa tissue medium extract. In planta expression of low abundance, target metabolites were confirmed from infected A. cepa tissue extracts by LC-UV-MS. CONCLUSIONS: Secondary metabolite production was directly dependent and influenced by media conditions, resulting in the stimulated production of low abundance metabolites on host-derived media. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of macerated host tissue media can be applied in vitro to predict in planta expression of low abundance metabolites and aid in metabolite origin annotation during in planta metabolomic investigations at the host/pathogen interface.

Allium↗

PubMed2005

Ochratoxin A producing Penicillium verrucosum isolates from cereals reveal large AFLP fingerprinting variability.

AIMS: To examine if molecular amplified fragment length polymorphism (AFLP) fingerprinting of the only ochratoxin A-producing species in European cereals, Penicillium verrucosum, can be used as a method in hazard analysis using critical control points (HACCP). METHODS AND RESULTS: A total of 321 isolates of P. verrucosum were isolated from ochratoxin A-contaminated cereals from Denmark (oats), UK (wheat and barley) and Sweden (wheat). Of these, 236 produced ochratoxin A as determined by thin layer chromatography; 185 ochratoxin A-producing isolates were selected for AFLP fingerprinting. A total of 138 isolates had unique AFLP patterns, whereas 52 isolates could be allocated to small groups containing from two to four isolates with similar AFLP patterns. A total of 155 clones were found among the 185 P. verrucosum isolates, thus 84% of the isolates may represent different genets of P. verrucosum. As the few isolates that were grouped often came from the same farm, and those groups that contained AFLP-identical isolates from different countries were morphotypically different. On single farms up to 35 clones were found. The few groups of ramets from the same genet indicated that a HACCP approach based on clones may require a very large number of AFLP analysis to work in practice, we recommend basing the HACCP approach on the actual species P. verrucosum. A more detailed characterization should rather be based on the profile of species present at different control points, or analysis of the mycotoxins ochratoxin A and citrinin in the isolates. Examination of 86 isolates with HPLC and diode array detection of P. verrucosum showed that 66% produced ochratoxin A, 87% produced citrinin, 92% produced verrucin and 100% produced verrucolone. CONCLUSIONS: Among 184 ochratoxin A-producing Penicillium verrucosum, 155 clonal lineages were indicated by AFLP fingerprinting, indicating a high genetical diversity, yet the species P. verrucosum is phenotypically distinct and valid. SIGNIFICANCE AND IMPACT OF THE STUDY: AFLP fingerprinting of Penicillium verrucosum indicates that genetic recombination takes place in this fungus.

Avena↗

PubMed2005

Mycotoxin production and postharvest storage rot of ginger (Zingiber officinale) by Penicillium brevicompactum.

Twenty naturally infected ginger (Zingiber officinale) rhizomes displaying visible mold growth were examined to identify the fungi and to evaluate the presence of fungal secondary metabolites. Penicillium brevicompactum was the predominant species isolated from 85% of the samples. Mycophenolic acid was identified from corresponding tissue extracts. Because mycophenolic acid is a potent immunosuppressant and synergistic mycotoxicosis studies involving human consumption have not been carried out on this metabolite, spoilage of commercially marketed produce caused by P. brevicompactum is a concern. This is the first reported occurrence of mycophenolic acid in commercially sold plant food products.

Consumer Product Safety↗

PubMed2004

Emericella astellata, a new producer of aflatoxin B, B and sterigmatocystin.

AIMS: To report on aflatoxin B(1) and B(2) production from a species of Emericella. METHODS AND RESULTS: Aflatoxins and sterigmatocystin were determined by high-pressure liquid chromatography (HPLC) with diode array detection and confirmed by HPLC with mass spectrometry detection. Among 30 known species of Emericella only one species produced aflatoxin. Strains originating from the same geographical source material had different patterns of aflatoxin and sterigmatocystin production on different media, indicating that epigenetic factors may be involved in the regulation of aflatoxin production. However, two cultures from the same original genet were very similar. CONCLUSIONS: Emericella astellata can produce small amounts of sterigmatocystin and aflatoxin B(1) and B(2). SIGNIFICANCE AND IMPACT OF THE STUDY: Emericella has been used extensively in genetic studies and therefore the isolates producing aflatoxin can be used to elucidate the genetic, evolutionary and maybe ecological role of aflatoxins using molecular genetic methods.

Aflatoxin B1↗

PubMed2003

Penicillium verrucosum in wheat and barley indicates presence of ochratoxin A.

AIMS: The aims of this study were to isolate and identify ochratoxin A (OTA) producing fungi in cereals containing OTA and to determine the best selective and indicative medium for recovery of OTA producing fungi. METHODS AND RESULTS: Seventy-six wheat, barley and rye samples from Europe containing OTA and 17 samples without OTA were investigated using three different media, dichloran yeast sucrose agar (DYSG), dichloran rose bengal yeast extract sucrose agar (DRYES) and dichloran 18% glycerol agar (DG18). Hundred kernels were plated on each medium and the kind and number of fungal OTA producers were recorded as percentage of infestation. Penicillium verrucosum was the sole OTA producer found in cereals. The average percentage of infestation of P. verrucosum counts was recorded as 28.3% on DYSG, 10.3% on DRYES and 9.9% on DG18 on the OTA containing samples and 0.8% on DYSG, 0.4% on DRYES and 0.6% on DG18 for the samples without OTA. CONCLUSIONS: Penicillium verrucosum was the sole OTA producer in European cereals. Determination of P. verrucosum infestation and infection was best detected on DYSG after 7 days at 20 degrees C. The percentage of infestation of P. verrucosum found on DYSG and OTA content in cereals were correlated. More than 7% infestation of P. verrucosum indicated OTA contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: The developed method could be used as a cereal quality control.

Culture Media↗

PubMed2002

On the safety of Aspergillus niger--a review.

Aspergillus niger is one of the most important microorganisms used in biotechnology. It has been in use already for many decades to produce extracellular (food) enzymes and citric acid. In fact, citric acid and many A. niger enzymes are considered GRAS by the United States Food and Drug Administration. In addition, A. niger is used for biotransformations and waste treatment. In the last two decades, A. niger has been developed as an important transformation host to over-express food enzymes. Being pre-dated by older names, the name A. niger has been conserved for economical and information retrieval reasons and there is a taxonomical consensus based on molecular data that the only other common species closely related to A. niger in the Aspergillus series Nigri is A. tubingensis. A. niger, like other filamentous fungi, should be treated carefully to avoid the formation of spore dust. However, compared with other filamentous fungi, it does not stand out as a particular problem concerning allergy or mycopathology. A few medical cases, e.g. lung infections, have been reported, but always in severely immunocompromised patients. In tropical areas, ear infections (otomycosis) do occur due to A. niger invasion of the outer ear canal but this may be caused by mechanical damage of the skin barrier. A. niger strains produce a series of secondary metabolites, but it is only ochratoxin A that can be regarded as a mycotoxin in the strict sense of the word. Only 3-10% of the strains examined for ochratoxin A production have tested positive under favourable conditions. New and unknown isolates should be checked for ochratoxin A production before they are developed as production organisms. It is concluded, with these restrictions, that A. niger is a safe production organism.

Aspergillosis↗

PubMed2000

Secondary metabolites characteristic of Penicillium citrinum, Penicillium steckii and related species.

Two new carboxylic acids, tanzawaic acid E (1) and F (2) in addition to the unknown benzopyran 3,7-dimethyl-1,8-dihydroxy-6-methoxy-isochroman (3), and the known mycotoxin 3,7-dimethyl-8-hydroxy-6-methoxyisochroman (4) were produced by a marine-derived strain of Penicillium steckii isolated from an unidentified tunicate. The carboxylic acids and the benzopyran were identified on the basis of mass spectrometry, and one and two dimensional NMR spectroscopic techniques. The structures 1 and 2 resemble tanzawaic acid A-D, previously isolated from Penicillium citrinum. Screening of isolates of species related to P. citrinum and P. steckii showed that P. citrinum (25 isolates) consistently produced citrinin and tanzawaic acid A, P. steckii (18 isolates) produced isochroman toxins (except 2) and tanzawaic acid E, P. sizovae consistently produced tanzawaic acid A, P. corylophilum (10 isolates) produced citreoisocoumarinol and P. sumatrense (15 isolates) always produced curvularin.

Animals↗

PubMed2000

An amendment of Aspergillus section Candidi based on chemotaxonomical evidence.

A novel 2,2'-epoxy-terphenyllin, candidusin C, in addition to the well known secondary metabolites terphenyllin, 3-hydroxyterpenyllin and chlorflavonin, has been isolated from the chemically unexplored fungus Aspergillus campestris. The latter three are known secondary metabolites from Aspergillus candidus and therefore a large number of Aspergilli were screened for production of these compounds to see whether they could be regarded as chemotaxonomical indicators of section membership in the monotypic Aspergillus section Candidi. The results indicated that A. campestris and A. taichungensis should be placed in Candidi and this was further confirmed by morphological and physiological similarities. Three species outside the section Candidi produced candidusin related secondary metabolites: Aspergillus arenarius, A. ellipticus and Penicillium raistrickii. Chlorflavonin, however, was only found in section Candidi.

Aspergillus↗

PubMed2000

Direct identification of pure Penicillium species using image analysis.

This paper presents a method for direct identification of fungal species solely by means of digital image analysis of colonies as seen after growth on a standard medium. The method described is completely automated and hence objective once digital images of the reference fungi have been established. Using a digital image it is possible to extract precise information from the surface of the fungal colony. This includes color distribution, colony dimensions and texture measurements. For fungal identification, this is normally done by visual observation that often results in a very subjective data recording. Isolates of nine different species of the genus Penicillium have been selected for the purpose. After incubation for 7 days, the fungal colonies are digitized using a very accurate digital camera. Prior to the image analysis each image is corrected for self-illumination, thereby gaining a set of directly corresponding images with respect to illumination. A Windows application has been developed to locate the position and size of up to three colonies in the digitized image. Using the estimated positions and sizes of the colonies, a number of relevant features can be extracted for further analysis. The method used to determine the position of the colonies will be covered as well as the feature selection. The texture measurements of colonies of the nine species were analyzed and a clustering of the data into the correct species was confirmed. This indicates that it is indeed possible to identify a given colony merely by macromorphological features. A classifier (in the normal distribution) based on measurements of 151 colonies incubated on yeast extract sucrose agar (YES) was used to discriminate between the species. This resulted in a correct classification rate of 100% when used on the training set and 96% using cross-validation. The same methods applied to 194 colonies incubated on Czapek yeast extract agar (CYA) resulted in a correct classification rate of 98% on the training set and 71% using cross-validation.

Color↗

PubMed1999

Full second-order chromatographic/spectrometric data matrices for automated sample identification and component analysis by non-data-reducing image analysis.

A data analysis method is proposed for identification and for confirmation of classification schemes, based on single- or multiple-wavelength chromatographic profiles. The proposed method works directly on the chromatographic data without data reduction procedures such as peak area or retention index calculation. Chromatographic matrices from analysis of previously identified samples are used for generating a reference chromatogram for each class, and unidentified samples are compared with all reference chromatograms by calculating a resemblance measure for each reference. Once the method is configured, subsequent sample identification is automatic. As an example of a further development, it is shown how the method allows identification of characteristic sample components by local similarity calculations thus finding common components within a given class as well as component differences between classes from the reference chromatograms. This feature is a valuable aid in selecting components for further analysis. The identification method is demonstrated on two data sets: 212 isolates from 41 food-borne Penicillium species and 61 isolates from 6 soil-borne Penicillium species. Both data sets yielded over 90% agreement with accepted classifications. The method is highly accurate and may be used on all sorts of chromatographic profiles. Characteristic component analysis yielded results in good agreement with existing knowledge of characteristic components, but also succeeded in identifying new components as being characteristic.

Chromatography↗

PubMed1999

Production of mycotoxins on artificially and naturally infested building materials.

In this study, the ability to produce mycotoxins during growth on artificially infested building materials was investigated for Penicillium chrysogenum, Pen. polonicum, Pen. brevicompactum, Chaetomium spp., Aspergillus ustus, Asp. niger, Ulocladium spp., Alternaria spp., and Paecilomyces spp., all isolated from water-damaged building materials. Spores from the different isolates of the above mentioned species were inoculated on gypsum board with and without wallpaper and on chipboard with and without wallpaper. Fungal material was scraped off the materials, extracted, and analyzed using high performance liquid chromatography-diode array detection and thin layer chromatography. All six isolates of C. globosum produced the toxic chaetoglobosins A and C, at levels of up to 50 and 7 microg/cm2 respectively. The quantities of secondary metabolites produced by Penicillia were generally low, and no toxin production was detected from any of the five isolates of Pen. chrysogenum. Both isolates of Pen. polonicum produced 3-methoxy-viridicatin, verrucosidin, and verrucofortine. Two of five isolates of Pen. brevicompactum produced mycophenolic acid. From five out of six isolates of Alternaria spp., altenariol and alternariol monomethyl ether were detected. From Ulocladium spp., Paecilomyces spp., and Asp. ustus no known mycotoxins were detected, although the latter two are known mycotoxin producers. Asp. niger produced several naphtho-gamma-pyrones and tetra-cyclic compounds. All investigated species, especially Asp. ustus and Asp. niger produced many unknown secondary metabolites on the building materials. Analyses of wallpaper and glass-fibre wallpaper naturally infested with Asp. versicolor revealed sterigmatocystin and 5-methoxysterigmatocystin. Analyses of naturally infested wallpaper showed that C. globosum produced the chaetoglobosins A and C, and Pen. chrysogenum produced the antibiotic meleagrin.

Chromatography, High Pressure Liquid↗

PubMed1998

Protection by fungal starters against growth and secondary metabolite production of fungal spoilers of cheese.

The influence of fungal starter cultures on growth and secondary metabolite production of fungal contaminants associated with cheese was studied on laboratory media and Camembert cheese. Isolates of the species Penicillium nalgiovense, P. camemberti, P. roqueforti and Geotrichum candidum were used as fungal starters. The species P. commune, P. caseifulvum, P. verrucosum, P. discolor, P. solitum, P. coprophilum and Aspergillus versicolor were selected as contaminants. The fungal starters showed different competitive ability on laboratory media and Camembert cheese. The presence of the Penicillium species, especially P. nalgiovense, showed an inhibitory effect on the growth of the fungal contaminants on laboratory media. G. candidum caused a significant inhibition of the fungal contaminants on Camembert cheese. The results indicate that G. candidum plays an important role in competition with undesirable microorganisms in mould fermented cheeses. Among the starters, P. nalgiovense caused the largest reduction in secondary metabolite production of the fungal contaminants on the laboratory medium. On Camembert cheese no significant changes in metabolite production of the fungal contaminants was observed in the presence of the starters.

Aflatoxins↗

PubMed1998

UV-Guided isolation of alantrypinone, a novel Penicillium alkaloid.

Fumiquinazoline F (1) and alantrypinone (2) have been isolated as the two major metabolites of Penicillium thymicola. The structure of 2, which contains a new ring structure, was elucidated by analysis of spectroscopic data including 2D NMR. The absolute configuration of 2 was established by a single-crystal X-ray diffraction study.

Alkaloids↗

PubMed1998

Colony interaction and secondary metabolite production of cheese-related fungi in dual culture.

Interactions between fungi used as starter cultures (Penicillium roqueforti, Penicillium camemberti, Penicillium nalgiovense, and Geotrichum candidum) and fungal contaminants associated with cheese were investigated on agar medium at two temperatures, 18 and 25 degrees C. Mutual inhibition on contact was the most common interaction observed. The only other interaction observed was inhibition of the contaminant, while the starter continued to grow, especially in dual cultures involving G. candidum as the starter culture. Dual cultures involving G. candidum showed inhibition of production of the mycotoxins mycophenolic acid, roquefortin C, chaetoglobosin A, and cyclopiazonic acid produced by the contaminants. An unknown metabolite was detected in considerably larger quantity in dual cultures involving G. candidum compared to detection in single cultures. There was no correlation between detection of this metabolite and the observed interactions. The results show that G. candidum plays a major role in interactions between fungi on cheese.

Cheese↗

PubMed1997

Penicillium discolor, a new species from cheese, nuts and vegetables.

The new species Penicillium discolor, frequently isolated from nuts, vegetables and cheese is described. It is characterised by rough, dark green conidia, synnemateous growth on malt agar and the production of the secondary metabolites chaetoglobosins A, B and C, palitantin, cyclopenin, cyclopenol, cyclopeptin, dehydrocyclopeptin, viridicatin and viridicatol. It also produces the mouldy smelling compounds geosmin and 2-methyl-isoborneol, and a series of specific orange to red pigments on yeast extract sucrose agar, hence the epithet discolor. P. discolor resembles P. echinulatum morphologically but on basis of the secondary metabolites is also related to P. expansum, P. solitum and P. crustosum.

Benzodiazepinones↗

PubMed1997

The contribution of moulds and yeasts to the fermentation of 'agbelima' cassava dough.

Agbelima, a fermented cassava meal widely consumed in Ghana, Togo and Benin, is produced by fermenting grated cassava with one of several types of traditional cassava dough inoculum. During fermentation a smooth textured sour dough is produced, the toxicity of cassava is reduced and there is a build up of volatile aroma compounds. Four types of inocula were included in the present investigation. In one type moulds were found to form a dominant part of the microbiota, the species present being Penicillium sclerotiorum, P. citrinum, P. nodulum, Geotrichum candidum and a basidiomycete. All these moulds were found to possess cellulase activity which was responsible for the hydrolysis of cassava tuber cellulose during fermentation leading to a breakdown of the coarse texture of cassava dough. The yeasts Candida krusei, C. tropicalis and Zygosaccharomyces spp. were present in high numbers in the four types of inocula including the moudly inoculum. The yeasts C. tropicalis and some strains of Zygosaccharomyces, all of which possessed cellulase activity, were also found to contribute to the modification of cassava texture during fermentation. All yeasts and moulds exhibited linamarase activity and were therefore capable of breaking down the cyanogenic glucosides present in cassava.

Basidiomycota↗

PubMed1997

A Penicillium freii gene that is highly similar to the beta-ketoacyl synthase domain of polyketide synthase genes from other fungi.

A Penicillium freii DNA fragment with similarity to the beta-keto-acyl synthase motif of the P. griseofulvum 6-methylsalicylic acid synthase encoding gene (MSAS) was identified by screening a cosmid library using a part of MSAS as the probe. Two exons of 93 and 849 bp, encoding a predicted polypeptide of 314 amino acids, and a molecular mass of 33.4 kDa, were identified (PfKS). PfKS was transcribed as a 1.6 kbp messenger. A region corresponding to the MSAS gene encoding essential enzyme activities for the assembly of a polyketide chain was absent in PfKS. Gene disruption experiments in P. freii with a truncated version of PfKS did not result in the detection of homologous integration events.

Base Sequence↗

PubMed1996

Micellar electrokinetic capillary chromatography of fungal metabolites. Resolution optimized by experimental design.

Fungal metabolites were extracted from two isolates of Penicillium commune and two isolates of Aspergillus versicolor grown on yeast extract agar (YES) and Czapek yeast extract agar (CYA). Optimized conditions for analysing the extracts by high-performance capillary electrophoresis (HPCE) were obtained by experimental designs. The following nine factors were examined by a two-level fractional factorial design: concentration of the buffer ion PO4(3-) and B4O7(2-), ionic strength of buffer, buffer pH, addition of sodium dodecyl sulphate (SDS) and sodium deoxycholate (SCD), addition of acetonitrile and methanol and voltage. Four factors significantly influenced the separation of peaks in all the fungal extracts. For optimization of the HPCE method a subsequent response-surface experiment with the important factors was made with an extract from an isolate of Aspergillus versicolor. Optimum separation conditions were obtained, which gave good resolution of the components in the extract.

Aspergillus↗