Andrastins A-D, Penicillium roqueforti Metabolites consistently produced in blue-mold-ripened cheese

Secondary Metabolites Produced by the Blue-Cheese Ripening Mold Penicillium roqueforti; Biosynthesis and Regulation Mechanisms

Filamentous fungi are an important source of natural products. The mold Penicillium roqueforti, which is well-known for being responsible for the characteristic texture, blue-green spots, and aroma of the so-called blue-veined cheeses (French Bleu, Roquefort, Gorgonzola, Stilton, Cabrales, and Valdeón, among others), is able to synthesize different secondary metabolites, including andrastins and mycophenolic acid, as well as several mycotoxins, such as Roquefortines C and D, PR-toxin and eremofortins, Isofumigaclavines A and B, festuclavine, and Annullatins D and F. This review provides a detailed description of the biosynthetic gene clusters and pathways of the main secondary metabolites produced by P. roqueforti, as well as an overview of the regulatory mechanisms controlling secondary metabolism in this filamentous fungus.

Analysis of Mycotoxin and Secondary Metabolites in Commercial and Traditional Slovak Cheese Samples

Cheese represents a dairy product extremely inclined to fungal growth and mycotoxin production. The growth of fungi belonging to Aspergillus, Penicillium, Fusarium, Claviceps, Alternaria, and Trichoderma genera in or on cheese leads to undesirable changes able to affect the quality of the final products. In the present investigation, a total of 68 types of commercial and traditional Slovak cheeses were analyzed to investigate the occurrence of fungal metabolites. Altogether, 13 fungal metabolites were identified and quantified. Aflatoxin M1, the only mycotoxin regulated in milk and dairy products, was not detected in any case. However, the presence of metabolites that have never been reported in cheeses, such as tryptophol at a maximum concentration level from 13.4 to 7930 µg/kg (average: 490 µg/kg), was recorded. Out of all detected metabolites, enniatin B represents the most frequently detected mycotoxin (0.06–0.71 µg/kg) in the analyzed samples. Attention is drawn to the lack of data on mycotoxins’ origin from Slovak cheeses; in fact, this is the first reported investigation. Our results indicate the presence of fungal mycotoxin contamination for which maximum permissible levels are not established, highlighting the importance of monitoring the source and producers of contamination in order to protect consumers’ health.

Oxandrastins: Antibacterial Meroterpenes from an Australian Mud Dauber Wasp Nest-Associated Fungus, Penicillium sp. CMB-MD14

The ethyl acetate extract of an ISP-2 agar cultivation of the wasp nest-associated fungus Penicillium sp. CMB-MD14 exhibited promising antibacterial activity against vancomycin-resistant enterococci (VRE), with a bioassay guided chemical investigation yielding the new meroterpene, oxandrastin A (1), the first andrastin-like metabolite with an extra oxygenation at C-2. A culture media optimisation strategy informed a scaled-up rice cultivation that yielded 1, together with three new oxandrastins B-D (2-4), two known andrastins C (5) and F (6), and a new meroterpene of the austalide family, isoaustalide F (7). Structures of 1-7 were assigned based on detailed spectroscopic analysis and chemical interconversion. A GNPS molecular networking analysis of the rice cultivation extract detected the known austalides B (8), H (9), and H acid (10), tentatively identified based on molecular formulae and co-clustering with 7. That the anti-VRE properties of the CMB-MD14 extract were exclusively attributed to 1 (IC₅₀ 6.0 µM, MIC₉₉ 13.9 µM), highlights the importance of the 2-OAc and 3-OAc moieties to the oxandrastin anti-VRE pharmacophore.

Mycotoxigenic and phylogenetic perspective to the yeasts and filamentous moulds in mould-matured Turkish cheese

This study was conducted to determine the diversity of yeasts and filamentous moulds in mould-matured cheese (MMC) consumed in Turkey. Overall, 120 samples were collected from 12 different geographical locations between March 2016 and April 2017. The morphological observation was applied in combination with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and molecular analyses to determine yeasts and filamentous moulds in the cheeses. High-performance liquid chromatography (HPLC) technique was used to evaluate the ability of mycotoxins production of fungal isolates and the presence of mycotoxins in cheese samples. A total of 241 fungi (81 filamentous moulds and 160 yeast) were recovered, and Penicillium roqueforti and Debaryomyces hansenii were the most frequently isolated species in all cheese samples. The rep-PCR results indicated a high level of genetic diversity among fungal isolates, regardless of isolation source or geographical origin. Filamentous mould strains isolated from MMC were found to synthesize at least one mycotoxin (Aflatoxin B₁, B₂, G₁ and G₂, citrinine, cyclopiazonic acid, mycophenolic acid, ochratoxin A, penicillic acid and roquefortine C). Although mycotoxin producing ability was observed from all isolates, none of the cheese samples were found positive for these mycotoxins. AFM₁ was detected in 8 (6.6%) MMC samples from which 2 (1.6%) were above the legal limits (0.05 μg/kg) set by the Turkish Food Codex (TFC) and European Commission (EC). In conclusion, Turkish MMCs were found to be contaminated with toxigenic fungi, so a potential public health risk, while low, exists. Therefore, the selection of nontoxigenic filamentous mould strains for cheese manufacturing and control of the ripening conditions is a critical need to ensure the quality and safety of Turkish MMC.

A Review on the General Cheese Processing Technology, Flavor Biochemical Pathways and the Influence of Yeasts in Cheese

Cheese has a long history and this naturally fermented dairy product contains a range of distinctive flavors. Microorganisms in variety cheeses are an essential component and play important roles during both cheese production and ripening. However, cheeses from different countries are still handmade, the processing technology is diverse, the microbial community structure is complex and the cheese flavor fluctuates greatly. Therefore, studying the general processing technology and relationship between microbial structure and flavor formation in cheese is the key to solving the unstable quality and standardized production of cheese flavor on basis of maintaining the flavor of cheese. This paper reviews the research progress on the general processing technology and key control points of natural cheese, the biochemical pathways for production of flavor compounds in cheeses, the diversity and the role of yeasts in cheese. Combined with the development of modern detection technology, the evolution of microbial structure, population evolution and flavor correlation in cheese from different countries was analyzed, which is of great significance for the search for core functional yeast microorganisms and the industrialization prospect of traditional fermented cheese.

Diversity, Bioactivity Profiling and Untargeted Metabolomics of the Cultivable Gut Microbiota of Ciona intestinalis

It is widely accepted that the commensal gut microbiota contributes to the health and well-being of its host. The solitary tunicate Ciona intestinalis emerges as a model organism for studying host-microbe interactions taking place in the gut, however, the potential of its gut-associated microbiota for marine biodiscovery remains unexploited. In this study, we set out to investigate the diversity, chemical space, and pharmacological potential of the gut-associated microbiota of C. intestinalis collected from the Baltic and North Seas. In a culture-based approach, we isolated 61 bacterial and 40 fungal strains affiliated to 33 different microbial genera, indicating a rich and diverse gut microbiota dominated by Gammaproteobacteria. In vitro screening of the crude microbial extracts indicated their antibacterial (64% of extracts), anticancer (22%), and/or antifungal (11%) potential. Nine microbial crude extracts were prioritized for in-depth metabolome mining by a bioactivity- and chemical diversity-based selection procedure. UPLC-MS/MS-based metabolomics combining automated (feature-based molecular networking and in silico dereplication) and manual approaches significantly improved the annotation rates. A high chemical diversity was detected where peptides and polyketides were the predominant classes. Many compounds remained unknown, including two putatively novel lipopeptides produced by a Trichoderma sp. strain. This is the first study assessing the chemical and pharmacological profile of the cultivable gut microbiota of C. intestinalis.

Classification of Aspergillus, Penicillium, Talaromyces and related genera (Eurotiales): An overview of families, genera, subgenera, sections, series and species

The Eurotiales is a relatively large order of Ascomycetes with members frequently having positive and negative impact on human activities. Species within this order gain attention from various research fields such as food, indoor and medical mycology and biotechnology. In this article we give an overview of families and genera present in the Eurotiales and introduce an updated subgeneric, sectional and series classification for Aspergillus and Penicillium. Finally, a comprehensive list of accepted species in the Eurotiales is given. The classification of the Eurotiales at family and genus level is traditionally based on phenotypic characters, and this classification has since been challenged using sequence-based approaches. Here, we re-evaluated the relationships between families and genera of the Eurotiales using a nine-gene sequence dataset. Based on this analysis, the new family Penicillaginaceae is introduced and four known families are accepted: Aspergillaceae, Elaphomycetaceae, Thermoascaceae and Trichocomaceae. The Eurotiales includes 28 genera: 15 genera are accommodated in the Aspergillaceae (Aspergillago, Aspergillus, Evansstolkia, Hamigera, Leiothecium, Monascus, Penicilliopsis, Penicillium, Phialomyces, Pseudohamigera, Pseudopenicillium, Sclerocleista, Warcupiella, Xerochrysium and Xeromyces), eight in the Trichocomaceae (Acidotalaromyces, Ascospirella, Dendrosphaera, Rasamsonia, Sagenomella, Talaromyces, Thermomyces, Trichocoma), two in the Thermoascaceae (Paecilomyces, Thermoascus) and one in the Penicillaginaceae (Penicillago). The classification of the Elaphomycetaceae was not part of this study, but according to literature two genera are present in this family (Elaphomyces and Pseudotulostoma). The use of an infrageneric classification system has a long tradition in Aspergillus and Penicillium. Most recent taxonomic studies focused on the sectional level, resulting in a well-established sectional classification in these genera. In contrast, a series classification in Aspergillus and Penicillium is often outdated or lacking, but is still relevant, e.g., the allocation of a species to a series can be highly predictive in what functional characters the species might have and might be useful when using a phenotype-based identification. The majority of the series in Aspergillus and Penicillium are invalidly described and here we introduce a new series classification. Using a phylogenetic approach, often supported by phenotypic, physiologic and/or extrolite data, Aspergillus is subdivided in six subgenera, 27 sections (five new) and 75 series (73 new, one new combination), and Penicillium in two subgenera, 32 sections (seven new) and 89 series (57 new, six new combinations). Correct identification of species belonging to the Eurotiales is difficult, but crucial, as the species name is the linking pin to information. Lists of accepted species are a helpful aid for researchers to obtain a correct identification using the current taxonomic schemes. In the most recent list from 2014, 339 Aspergillus, 354 Penicillium and 88 Talaromyces species were accepted. These numbers increased significantly, and the current list includes 446 Aspergillus (32 % increase), 483 Penicillium (36 % increase) and 171 Talaromyces (94 % increase) species, showing the large diversity and high interest in these genera. We expanded this list with all genera and species belonging to the Eurotiales (except those belonging to Elaphomycetaceae). The list includes 1 187 species, distributed over 27 genera, and contains MycoBank numbers, collection numbers of type and ex-type cultures, subgenus, section and series classification data, information on the mode of reproduction, and GenBank accession numbers of ITS, beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) gene sequences.

Mining the Metabolome and the Agricultural and Pharmaceutical Potential of Sea Foam-Derived Fungi

Sea foam harbors a diverse range of fungal spores with biological and ecological relevance in marine environments. Fungi are known as the producers of secondary metabolites that are used in health and agricultural sectors, however the potentials of sea foam-derived fungi have remained unexplored. In this study, organic extracts of six foam-derived fungal isolates belonging to the genera Penicillium, Cladosporium, Emericellopsis and Plectosphaerella were investigated for their antimicrobial activity against plant and human pathogens and anticancer activity. In parallel, an untargeted metabolomics study using UPLC-QToF–MS/MS-based molecular networking (MN) was performed to unlock their chemical inventory. Penicillium strains were identified as the most prolific producers of compounds with an average of 165 parent ions per strain. In total, 49 known mycotoxins and functional metabolites were annotated to specific and ubiquitous parent ions, revealing considerable chemical diversity. This allowed the identification of putative new derivatives, such as a new analog of the antimicrobial tetrapeptide, fungisporin. Regarding bioactivity, the Penicillium sp. isolate 31.68F1B showed a strong and broad-spectrum activity against seven plant and human pathogens, with the phytopathogen Magnaporthe oryzae and the human pathogen Candida albicans being the most susceptible (IC₅₀ values 2.2 and 6.3 µg/mL, respectively). This is the first study mining the metabolome of the sea foam-derived fungi by MS/MS-based molecular networking, and assessing their biological activities against phytopathogens.

Tyrosine Induced Metabolome Alterations of Penicillium roqueforti and Quantitation of Secondary Key Metabolites in Blue-Mold Cheese

To map qualitative and quantitative metabolome alterations when Penicillium roqueforti is grown in an environment where l-tyrosine levels are perturbed, the recently established differential off-line LC-NMR (DOLC-NMR) approach was successfully applied in connection with an absolute metabolite quantitation using a quantitative ¹H NMR protocol following the ERETIC 2 (Electronic REference To access In vivo Concentrations) methodology. Among the 23 influenced metabolites, amino acid degradation products like 2-(4-hydroxyphenyl)acetic acid and 2-(3,4-dihydroxyphenyl)acetic acid underwent a tremendous upregulation in the amino acid perturbed approach. Moreover, the output of secondary metabolites like andrastin A, eremofortin B, and the tetrapeptide d-Phe-l-Val-d-Val-l-Tyr was affected in the case of the presence or absence of the added aromatic amino acid. Furthermore, the isolated secondary metabolites of P. roqueforti have been quantified for the first time in five divergent Penicillium isolates by means of a validated LC-ECHO-MS/MS method. This technique is used to compensate the effect of co-extracted matrix compounds during the analysis and to utilize quasi-internal standards to quantify all metabolites of interest accurately. This screening outlined the great variety between the different fungi of the same species. The metabolite spectra of wild-type fungi included more toxic intermediates compared to a selected fungi used as a starter culture for blue-mold cheese production. In addition, these secondary metabolites were quantified in commercially available white- and blue-mold cheese samples. The main differences between the analyte profiles of white and blue cheeses were linked to the impact of the used starter culture. Specific metabolites detected from P. roqueforti like andrastin A and B or roquefortine C could not be detected in white cheese. Among the blue cheese samples, different metabolite pattern could be observed regarding various P. roqueforti starter cultures.

Functional Metabolome Analysis of Penicillium roqueforti by Means of Differential Off-Line LC-NMR

UPLC-TOF/MS profiling, followed by the recently reported differential off-line LC-NMR (DOLC-NMR) and quantitative ¹H NMR spectroscopy (qHNMR), led to the differential qualitative analysis and accurate quantitation of l-tryptophan-induced metabolome alterations of Penicillium roqueforti, which is typically used in making blue-mold cheese. Among the 24 metabolites identified, two tetrapeptides, namely, d-Phe-l-Val-d-Val-l-Tyr and d-Phe-l-Val-d-Val-l-Phe, as well as cis-bis(methylthio)silvatin, are reported for the first time as metabolites of P. roqueforti. Antimicrobial activity tests showed strong effects of the catabolic l-tryptophan metabolites 3-hydroxyanthranilic acid, anthranilic acid, and 3-indolacetic acid against Saccharomyces cerevisiae, with IC₅₀ values between 15.6 and 24.0 μg/mL, while roquefortine C and cis-bis(methylthio)silvatin inhibited the growth of Gram-negative Escherichia coli and Gram-positive Bacillus subtilis with IC₅₀ values between 30.0 and 62.5 μg/mL.

French and Mediterranean-style diets: Contradictions, misconceptions and scientific facts-A review

The determination of appropriate dietary strategies for the prevention of chronic degenerative diseases, cancer, diabetes, and cardiovascular diseases remains a challenging and highly relevant issue worldwide. Epidemiological dietary interventions have been studied for decades with contrasting impacts on human health. Moreover, research scientists and physicians have long debated diets encouraging alcohol intake, such as the Mediterranean and French-style diets, with regard to their impact on human health. Understanding the effects of these diets may help to improve in the treatment and prevention of diseases. However, further studies are warranted to determine which individual food components, or combinations thereof, have a beneficial impact on different diseases, since a large number of different compounds may occur in a single food, and their fate in vivo is difficult to measure. Most explanations for the positive effects of Mediterranean-style diet, and of the French paradox, have focused largely on the beneficial properties of antioxidants, among other compounds/metabolites, in foods and red wine. Wine is a traditional alcoholic beverage that has been associated with both healthy and harmful effects. Not withstanding some doubts, there is reasonable unanimity among researchers as to the beneficial effects of moderate wine consumption on cardiovascular disease, diabetes, osteoporosis, and longevity, which have been ascribed to polyphenolic compounds present in wine. Despite this, conflicting findings regarding the impact of alcohol consumption on human health, and contradictory findings concerning the effects of non-alcoholic wine components such as resveratrol, have led to confusion among consumers. In addition to these contradictions and misconceptions, there is a paucity of human research studies confirming known positive effects of polyphenols in vivo. Furthermore, studies balancing both known and unknown prognostic factors have mostly been conducted in vitro or using animal models. Moreover, current studies have shifted focus from red wine to dairy products, such as cheese, to explain the French paradox. The aim of this review is to highlight the contradictions, misconceptions, and scientific facts about wines and diets, giving special focus to the Mediterranean and French diets in disease prevention and human health improvement. To answer the multiplicity of questions regarding the effects of diet and specific diet components on health, and to relieve consumer uncertainty and promote health, comprehensive cross-demographic studies using the latest technologies, which include foodomics and integrated omics approaches, are warranted.

Brasilianoids A-F, New Meroterpenoids From the Sponge-Associated Fungus Penicillium brasilianum

3,5-Dimethylorsellinic acid (DMOA) derived meroterpenoids comprise an unique class of natural products with diverse scaffolds and with a broad spectrum of bioactivities. Bioinformatics analysis of the gene clusters in association with the qRT-PCR detection of the amplification of two key genes led to speculate that the sponge associated fungus Penicillium brasilianum WZXY-m122-9 is a potential producer of meroterpenoids. Chromatographic separation of the EtOAc extract of this fungal strain on a large-scale fermentation resulted in the isolation of six new DMOA-related meroterpenoids with trivial names of brasilianoids A–F (1-6), together with preaustinoid D and preaustinoid A2. The structures were determined by extensive analyses of spectroscopic data, including the X-ray diffraction and the ECD data for configurational assignment. Brasilianoids A and F showed an unprecedented skeleton with a γ-lactone in ring A, while brasilianoids B–C featured a 7/6/6/5/5 pentacyclic ring system finding in nature for the first time. The biosynthetic relationship among the isolated compounds was postulated. Compound 1 significantly stimulated the expression of filaggrin and caspase-14 in HaCaT cells in dose-dependent manner, while compounds 2 and 3 showed moderate inhibition against NO production in LPS-induced RAW 264.7 macrophages.

The Biosynthetic Gene Cluster for Andrastin A in Penicillium roqueforti

Penicillium roqueforti is a filamentous fungus involved in the ripening of several kinds of blue cheeses. In addition, this fungus produces several secondary metabolites, including the meroterpenoid compound andrastin A, a promising antitumoral compound. However, to date the genomic cluster responsible for the biosynthesis of this compound in P. roqueforti has not been described. In this work, we have sequenced and annotated a genomic region of approximately 29.4 kbp (named the adr gene cluster) that is involved in the biosynthesis of andrastin A in P. roqueforti. This region contains ten genes, named adrA, adrC, adrD, adrE, adrF, adrG, adrH, adrI, adrJ and adrK. Interestingly, the adrB gene previously found in the adr cluster from P. chrysogenum, was found as a residual pseudogene in the adr cluster from P. roqueforti. RNA-mediated gene silencing of each of the ten genes resulted in significant reductions in andrastin A production, confirming that all of them are involved in the biosynthesis of this compound. Of particular interest was the adrC gene, encoding for a major facilitator superfamily transporter. According to our results, this gene is required for the production of andrastin A but does not have any role in its secretion to the extracellular medium. The identification of the adr cluster in P. roqueforti will be important to understand the molecular basis of the production of andrastin A, and for the obtainment of strains of P. roqueforti overproducing andrastin A that might be of interest for the cheese industry.

Oxidative Cyclization in Natural Product Biosynthesis

Oxidative cyclizations are important transformations that occur widely during natural product biosynthesis. The transformations from acyclic precursors to cyclized products can afford morphed scaffolds, structural rigidity, and biological activities. Some of the most dramatic structural alterations in natural product biosynthesis occur through oxidative cyclization. In this Review, we examine the different strategies used by nature to create new intra(inter)molecular bonds via redox chemistry. This Review will cover both oxidation- and reduction-enabled cyclization mechanisms, with an emphasis on the former. Radical cyclizations catalyzed by P450, nonheme iron, α-KG-dependent oxygenases, and radical SAM enzymes are discussed to illustrate the use of molecular oxygen and S-adenosylmethionine to forge new bonds at unactivated sites via one-electron manifolds. Nonradical cyclizations catalyzed by flavin-dependent monooxygenases and NAD(P)H-dependent reductases are covered to show the use of two-electron manifolds in initiating cyclization reactions. The oxidative installations of epoxides and halogens into acyclic scaffolds to drive subsequent cyclizations are separately discussed as examples of "disappearing" reactive handles. Last, oxidative rearrangement of rings systems, including contractions and expansions, will be covered.

Biosynthetic gene clusters for relevant secondary metabolites produced by Penicillium roqueforti in blue cheeses

Ripening of blue-veined cheeses, such as the French Bleu and Roquefort, the Italian Gorgonzola, the English Stilton, the Danish Danablu or the Spanish Cabrales, Picón Bejes-Tresviso, and Valdeón, requires the growth and enzymatic activity of the mold Penicillium roqueforti, which is responsible for the characteristic texture, blue-green spots, and aroma of these types of cheeses. This filamentous fungus is able to synthesize different secondary metabolites, including andrastins, mycophenolic acid, and several mycotoxins, such as roquefortines C and D, PR-toxin and eremofortins, isofumigaclavines A and B, and festuclavine. This review provides a detailed description of the main secondary metabolites produced by P. roqueforti in blue cheese, giving a special emphasis to roquefortine, PR-toxin and mycophenolic acid, and their biosynthetic gene clusters and pathways. The knowledge of these clusters and secondary metabolism pathways, together with the ability of P. roqueforti to produce beneficial secondary metabolites, is of interest for commercial purposes.

Diversity of yeast and mold species from a variety of cheese types

To generate a comprehensive profile of viable fungi (yeasts and molds) on cheese as it is purchased by consumers, 44 types of cheese were obtained from a local grocery store from 1 to 4 times each (depending on availability) and sampled. Pure cultures were obtained and identified by DNA sequence of the ITS region, as well as growth characteristics and colony morphology. The yeast Debaryomyces hansenii was the most abundant fungus, present in 79 % of all cheeses and 63 % of all samples. Penicillium roqueforti was the most common mold, isolated from a variety of cheeses in addition to the blue cheeses. Eighteen other fungal species were isolated, ten from only one sample each. Most fungi isolated have been documented from dairy products; a few raise potential food safety concerns (i.e. Aspergillus flavus, isolated from a single sample and capable of producing aflatoxins; and Candida parapsilosis, an emerging human pathogen isolated from three cheeses). With the exception of D. hansenii (present in most cheese) and P. roqueforti (a necessary component of blue cheese), no strong correlation was observed between cheese type, manufacturer, or sampling time with the yeast or mold species composition.

Secondary metabolites from Penicillium corylophilum isolated from damp buildings

Indoor exposure to the spores and mycelial fragments of fungi that grow on damp building materials can result in increased non-atopic asthma and upper respiratory disease. The mechanism appears to involve exposure to low doses of fungal metabolites. Penicillium corylophilum is surprisingly common in damp buildings in USA, Canada and western Europe. We examined isolates of P. corylophilum geographically distributed across Canada in the first comprehensive study of secondary metabolites of this fungus. The sesquiterpene phomenone, the meroterpenoids citreohybridonol and andrastin A, koninginin A, E and G, three new alpha pyrones and four new isochromans were identified from extracts of culture filtrates. This is the first report of koninginins, meroterpenoids and alpha pyrones from P. corylophilum. These secondary metabolite data support the removal of P. corylophilum from Penicillium section Citrina and suggest that further taxonomic studies are required on this species.

Roquefort cheese proteins inhibit Chlamydia pneumoniae propagation and LPS-induced leukocyte migration

Inflammation in atherosclerosis, which could be associated with some subclinical infections such as C. pneumoniae, is one of the key factors responsible for the development of clinical complications of this disease. We report that a proprietary protein extract isolated from Roquefort cheese inhibits the propagation of C. pneumoniae in a human HL cell line in a dose-dependent manner, as revealed by the immunofluorescence analysis. These changes were accompanied by a significant reduction in the infective progeny formation over the protein extract range of 0.12–0.5 μg/mL. Moreover, short term feeding of mice with Roquefort cheese (twice, 10 mg per mouse with an interval of 24 hours) led to the inhibition of the migration of peritoneal leukocytes caused by intraperitoneal injection of E. coli lipopolysaccharide. These changes were complemented by a reduction in neutrophil count and a relative increase in peritoneal macrophages, suggesting that ingestion of Roquefort could promote regenerative processes at the site of inflammation. The ability of this protein to inhibit propagation of Chlamydia infection, as well as the anti-inflammatory and proregenerative effects of Roquefort itself, may contribute to the low prevalence of cardiovascular mortality in France where consumption of fungal fermented cheeses is the highest in the world.

Atlantinone A, a Meroterpenoid Produced by Penicillium ribeum and Several Cheese Associated Penicillium Species

Atlantinone A has been isolated from the psychrotolerant fungus Penicillium ribeum. The exact structure of the compound was confirmed by mass spectrometric and 1- and 2D NMR experiments. Atlantinone A was originally only produced upon chemical epigenetic manipulation of P. hirayamae, however in this study the compound was found to be produced at standard growth conditions by the following species; P. solitum, P. discolor, P. commune, P. caseifulvum, P. palitans, P. novae-zeelandiae and P. monticola. A biosynthetic pathway to atlantinone A starting from andrastin A is proposed.

Ajoene, a sulfur-rich molecule from garlic, inhibits genes controlled by quorum sensing

In relation to emerging multiresistant bacteria, development of antimicrobials and new treatment strategies of infections should be expected to become a high-priority research area. Quorum sensing (QS), a communication system used by pathogenic bacteria like Pseudomonas aeruginosa to synchronize the expression of specific genes involved in pathogenicity, is a possible drug target. Previous in vitro and in vivo studies revealed a significant inhibition of P. aeruginosa QS by crude garlic extract. By bioassay-guided fractionation of garlic extracts, we determined the primary QS inhibitor present in garlic to be ajoene, a sulfur-containing compound with potential as an antipathogenic drug. By comprehensive in vitro and in vivo studies, the effect of synthetic ajoene toward P. aeruginosa was elucidated. DNA microarray studies of ajoene-treated P. aeruginosa cultures revealed a concentration-dependent attenuation of a few but central QS-controlled virulence factors, including rhamnolipid. Furthermore, ajoene treatment of in vitro biofilms demonstrated a clear synergistic, antimicrobial effect with tobramycin on biofilm killing and a cease in lytic necrosis of polymorphonuclear leukocytes. Furthermore, in a mouse model of pulmonary infection, a significant clearing of infecting P. aeruginosa was detected in ajoene-treated mice compared to a nontreated control group. This study adds to the list of examples demonstrating the potential of QS-interfering compounds in the treatment of bacterial infections.

Food as a source for quorum sensing inhibitors: iberin from horseradish revealed as a quorum sensing inhibitor of Pseudomonas aeruginosa

Foods with health-promoting effects beyond nutritional values have been gaining increasing research focus in recent years, although not much has been published on this subject in relation to bacterial infections. With respect to treatment, a novel antimicrobial strategy, which is expected to transcend problems with selective pressures for antibiotic resistance, is to interrupt bacterial communication, also known as quorum sensing (QS), by means of signal antagonists, the so-called QS inhibitors (QSIs). Furthermore, QSI agents offer a potential solution to the deficiencies associated with use of traditional antibiotics to treat infections caused by bacterial biofilms and multidrug-resistant bacteria. Several QSIs of natural origin have been identified, and in this study, several common food products and plants were extracted and screened for QSI activity in an attempt to isolate and characterize previously unknown QSI compounds active against the common opportunistic pathogen Pseudomonas aeruginosa. Several extracts displayed activity, but horseradish exhibited the highest activity. Chromatographic separation led to the isolation of a potent QSI compound that was identified by liquid chromatography-diode array detector-mass spectrometry (LC-DAD-MS) and nuclear magnetic resonance (NMR) spectroscopy as iberin-an isothiocyanate produced by many members of the Brassicaceae family. Real-time PCR (RT-PCR) and DNA microarray studies showed that iberin specifically blocks expression of QS-regulated genes in P. aeruginosa.

Food fermentations: microorganisms with technological beneficial use

Microbial food cultures have directly or indirectly come under various regulatory frameworks in the course of the last decades. Several of those regulatory frameworks put emphasis on "the history of use", "traditional food", or "general recognition of safety". Authoritative lists of microorganisms with a documented use in food have therefore come into high demand. One such list was published in 2002 as a result of a joint project between the International Dairy Federation (IDF) and the European Food and Feed Cultures Association (EFFCA). The "2002 IDF inventory" has become a de facto reference for food cultures in practical use. However, as the focus mainly was on commercially available dairy cultures, there was an unmet need for a list with a wider scope. We present an updated inventory of microorganisms used in food fermentations covering a wide range of food matrices (dairy, meat, fish, vegetables, legumes, cereals, beverages, and vinegar). We have also reviewed and updated the taxonomy of the microorganisms used in food fermentations in order to bring the taxonomy in agreement with the current standing in nomenclature.

Explorative solid-phase extraction (E-SPE) for accelerated microbial natural product discovery, dereplication, and purification

Microbial natural products (NP) cover a high chemical diversity, and in consequence extracts from microorganisms are often complex to analyze and purify. A distribution analysis of calculated pK(a) values from the 34390 records in Antibase2008 revealed that within pH 2-11, 44% of all included compounds had an acidic functionality, 17% a basic functionality, and 9% both. This showed a great potential for using ion-exchange chromatography as an integral part of the separation procedure, orthogonal to the classic reversed-phase strategy. Thus, we investigated the use of an "explorative solid-phase extraction" (E-SPE) protocol using SAX, Oasis MAX, SCX, and LH-20 columns for targeted exploitation of chemical functionalities. E-SPE provides a minimum of fractions (15) for chemical and biological analyses and implicates development into a preparative scale methodology. Overall, this allows fast extract prioritization, easier dereplication, mapping of biological activities, and formulation of a purification strategy.

Sample preparation

A panorama of sample preparation methods has been composed from 481 references, with a highlight of some promising methods fast developed during recent years and a somewhat brief introduction on most of the well-developed methods. All the samples were commonly referred to molecular composition, being extendable to particles including cells but not to organs, tissues and larger bodies. Some criteria to evaluate or validate a sample preparation method were proposed for reference. Strategy for integration of several methods to prepare complicated protein samples for proteomic studies was illustrated and discussed.

New materials in sorptive extraction techniques for polar compounds

This paper provides an overview of the new developments in material and format technology that improve the extraction of polar compounds in several extraction techniques. They mainly include solid-phase extraction, but there are also other sorptive extraction techniques, such as stir bar sorptive extraction and solid-phase microextraction that use either fibers or in-tube devices. We focus on new synthesised materials that are both commercially available and "in-house". Most novel materials that enhance the extraction of polar compounds are hydrophilic and have large specific surface area; however, we also cover other leading technologies, such as sol-gel or monolith. We describe the morphological and chemical properties of these new sorbents so that we can better understand them and relate them to their capability of retaining polar compounds. We discuss the extraction efficiency for polar compounds when these polymers are used as sorptive material and compare them to other materials. We also mention some representative examples of applications.

Phenotypic taxonomy and metabolite profiling in microbial drug discovery

Microorganisms and in particular actinomycetes and microfungi are known to produce a vast number of bioactive secondary metabolites. For industrially important fungal genera such as Penicillium and Aspergillus the production of these compounds has been demonstrated to be very consistent at the species level. This means that direct metabolite profiling techniques such as direct injection mass spectrometry or NMR can easily be used for chemotyping/metabolomics of strains from both culture collections and natural samples using modern informatics tools. In this review we discuss chemotyping/metabolomics as part of intelligent screening and highlight how it can be used for identification and classification of filamentous fungi and for the discovery of novel compounds when used in combination with modern methods for dereplication. In our opinion such approaches will be important for future effective drug discovery strategies, especially for dereplication of culture collections in order to avoid redundancy in the selection of species. This will maximize the chemical diversity of the microbial natural product libraries that can be generated from fungal collections.