Penicillic Acid Research Articles

Neurotoxicity of mycotoxins produced in vitro by Penicillium roqueforti isolated from maize and grass silage.

Fungal growth in human foods and animal feeds causes profound damage indicating a general spoilage, nutritional losses, and the formation of mycotoxins. Thirty apparently contaminated maize and grass silage samples were analyzed for the presence of total fungi. Penicillium roqueforti were isolated from all (100%) moldy silage samples on general and selective culture media. Furthermore, P. roqueforti-positive samples culture media subjected to the toxin extraction and toxins of patulin, penicillic acid, mycophenolic acid, and roquefortin-C (ROQ-C) were identified by means of high-performance liquid chromatography method. Cytotoxicity of identified toxins was investigated on neuro-2a cells. Alamar blue reduction, neutral red uptake, and intracellular adenosine triphosphate (ATP) content assays indicated that patulin and ROQ-C exert the strongest and weakest toxicity, respectively. Reactive oxygen species (ROS) generation by the toxins-exposed cells was measured, and the results supported the mitochondrial and lysosomal dysfunction and ATP depletion in exposed cells. Our data suggest that P. roqueforti is the widely present mold in analyzed maize and grass silage samples, which is able to produce toxins that cause neurotoxicity. This finding may explain in part some neuronal disorders in animals, which are fed contaminated feedstuffs with mentioned fungus. Moreover, mitochondrial and lysosomal dysfunction, intracellular ATP depletion, and the excessive ROS generation were found as the mechanisms of cytotoxicity for P. roqueforti-produced toxins.

Coculnol, a new penicillic acid produced by a coculture of Fusarium solani FKI-6853 and Talaromyces sp. FKA-65.

Coculnol, a new penicillic acid produced by a coculture of Fusarium solani FKI-6853 and Talaromyces sp. FKA-65

Mycotoxin production capability of Penicillium roqueforti in strains isolated from mould-ripened traditional Turkish civil cheese

Mould-ripened civil is a traditional cheese produced mainly in eastern Turkey. The cheese is produced with a mixture of civil and whey curd cheeses (lor). This mixture is pressed into goat skins or plastic bags and is ripened for more than three months. Naturally occurring moulds grow on the surface and inside of the cheese during ripening. In this research, 140 Penicillium roqueforti strains were isolated from 41 samples of mould-ripened civil cheese collected from Erzurum and around towns in eastern Turkey. All strains were capable of mycotoxin production and were analysed using an HPLC method. It was established that all the strains (albeit at very low levels) produced roquefortine C, penicillic acid, mycophenolic acid and patulin. The amounts of toxins were in the ranges 0.4–47.0, 0.2–43.6, 0.1–23.1 and 0.1–2.3 mg kg−1, respectively. Patulin levels of the samples were lower than the others. The lowest level and highest total mycotoxin levels were determined as 1.2 and 70.1 mg kg−1 respectively. The results of this preliminary study may help in the choice of secondary cultures for mould-ripened civil cheese and other mould-ripened cheeses.

First Report of Penicillium polonicum Causing Blue Mold on Stored Onion (Allium cepa) in Serbia.

Penicillium polonicum K. Zaleski is an economically important airborne fungus with a broad host range including cereals, peanuts, onions, dried meats, citrus fruits, and yam tubers (2,4). Secondary metabolites produced by this species include harmful mycotoxins penicillic acid, verucosidin, and nephrotoxic glycopeptides, which may play a role in Balkan Endemic Nephropathy (2,5). In January 2013, decayed onion bulbs (Allium cepa L. cv. Meranto) with blue mold symptoms were found causing significant economic losses at a storage facility in Stara Pazova, Serbia, and were collected. The decayed area of the bulbs was pale yellow to light brown, and tissue was soft and watery. Bluish green sporulation was abundant on the surface and inside the bulb, between decayed scales. Two isolates (designated L1a and L4p) were obtained and further characterized using morphological and molecular methods. Colonies on potato dextrose agar (PDA), Czapek yeast autolysate agar (CYA), malt extract agar (MEA), and yeast extract sucrose agar (YES) media at 25°C after 7 days were blue green, velutinous, with clear exudate present on CYA. Colony reverse color on CYA and YES for both isolates were cream to yellow brown. The mean colony diameter on PDA for L1a was 29.89 ± 0.96 mm, and for L4p was 26 ± 0.37 mm; on CYA 32.56 ± 0.53 mm for L1a and 30.11 ± 2.42 mm for L4p; and on YES 33.86 ± 1.59 mm for L1a and 31.17 ± 1.83 mm for L4p. No growth was observed on CYA when isolates were incubated at 37°C. Conidiophores of both isolates were terverticillate, stipes were septate with smooth to finely roughened walls, and phialides were ampulliform. Conidia were globose to subglobose, smooth-walled, and borne in columns. Conidial dimensions for L4p were 2.72 to 3.82 (3.26) × 2.36 to 3.42 (2.95) μm, and for L1a were 2.87 to 4.39 (3.58) × 2.53 to 3.79 (3.16) μm (n = 50). Both isolates tested positive for the production of cyclopiazonic acid and other alkaloids, as indicated by a violet reaction for the Ehrlich test. Morphological characters of L1a and L4p were in accordance with those described for P. polonicum K. Zaleski (2). Genomic DNA was isolated using CTAB extraction method (1) and molecular identification was completed using gene specific primers for the β-tubulin locus (Bt-LEV-Up4/Bt-LEV-Lo1) via conventional PCR (3). The nucleotide sequences of amplified products (~800 bp) have been assigned to GenBank (KJ570971 and 72). MegaBLAST of obtained sequences showed a 99% similarity with several sequences of P. polonicum deposited in GenBank, which confirmed the morphological identification. Pathogenicity was tested by wound inoculation of 10 surface sanitized onion bulbs cv. Meranto with 50 μl of a 105/ml conidial suspension from isolates grown on PDA. Ten control onion bulbs were wound-inoculated with Tween-treated sterile distilled water. After 30 days incubation in plastic containers, under high humidity at 22°C, typical symptoms of blue mold developed on inoculated bulbs, while non-inoculated controls remained symptomless. Isolates recovered from inoculated bulbs showed the same morphological characteristics as the original isolates, thus completing Koch's postulates. To our knowledge, this is the first report of P. polonicum on stored onion in Serbia. Results from this study indicate that a holistic approach to control this fungus should be implemented that may include one or all of the following: increased sanitation methods to eliminate inoculum, breeding for resistant onion cultivars, and integration of additional control methods to maintain onion quality during storage.

Penicillium strains isolated from Slovak grape berries taxonomy assessment by secondary metabolite profile.

The secondary metabolite profiles of microfungi of the genus Penicillium isolated from samples of grape berries collected in two different phases during two vegetative seasons in Slovakia is described to assess the taxonomy. Three Slovak vine regions have been selected for this study, based on their climatic differences and national economic importance. Cultures of microfungi isolated from berries were incubated on different selective media for macro and micromorphology identification. The species Penicillium brevicompactum, Penicillium crustosum, Penicillium chrysogenum, Penicillium expansum, Penicillium palitans and Penicillium polonicum were identified according to growth and morphology. The related strains were found to produce a broad spectrum of fungal metabolites, including roquefortine C, chaetoglobosin A, penitrem A, cyclopeptin, cyclopenin, viridicatin, methylviridicatin, verrucofortine, secalonic acid D, cyclopiazonic acid, fumigaclavine and mycophenolic acid. Chemotaxonomy was performed using high-performance liquid chromatography (HPLC) and mass spectrometry (MS). Dried grape berries were also analyzed allowing to assess the presence of patulin, roquefortine C and penicillic acid; this last one has been identified in dried berries but not in vitro.

A comprehensive study to explore differences in mycotoxin patterns from agro-ecological regions through maize, peanut, and cassava products: a case study, Cameroon.

A total of 420 samples were collected from agrarian households. Whereas 51% (215/420) of the samples were contaminated with one or more toxins, the contamination rates for maize, peanut, and cassava products were 74, 62, and 24%, respectively. The fumonisins (20-5412 μg/kg), aflatoxin B1 (6-645 μg/kg), roquefortine C (1-181 μg/kg), and deoxynivalenol (27-3842 μg/kg) were the most prevalent contaminants in maize. For peanut samples, aflatoxin B1 (6-125 μg/kg) and ochratoxin A (0.3-12 μg/kg) were the main contaminants, whereas aflatoxin B1 (6-194 μg/kg) and penicillic acid (25-184 μg/kg) were detected in the cassava products. Exposures calculated through maize intake for fumonisin B1 and aflatoxin B1 were several-fold higher (2-5 for fumonisin B1 and 10(4)-10(5) for aflatoxin B1) than the health-based guidance values of 2 μg/kg bw/day and 0.15 ng/kg bw/day, respectively. The study design constitutes a good model that can be implemented in other sub-Saharan African countries.

Characterization of Eight New Secondary Metabolites from the Mutant Strain G‐444 of Tubercularia sp. TF5

AbstractEight new metabolites, including five new sesquiterpenoids, 10,11‐epoxyguaian‐10‐ol (1), 10,11‐epoxyguaian‐13‐ol (2), a new backbone sesquiterpene rearranged from guaiane (3), two 1,5 : 1,10‐disecoguaianes, 4 and 5, two new dihydroisocoumarins, 7‐chloromellein‐4‐ol (6) and 7‐chloromellein‐5‐ol (7), and one new tetralone, 7‐chloroscytalone (8), were isolated from the mutant strain G‐444 of Tubercularia sp. TF5, an endophytic fungus of Taxus mairei, along with ten known compounds, 3,4‐dihydro‐4,8‐dihydroxy‐2H‐naphthalen‐1‐one (9), (3R,4S)‐4‐hydroxymellein (10), 5‐formylmellein (11), 5‐carboxymellein (12), sporogen‐AO1 (13), tuberculariols A (14) and B (15), hymatoxin E (16), 4‐oxo‐4H‐pyran‐3‐acetic acid (17), and penicillic acid (18). Their structures were elucidated by spectroscopic analyses including HR‐ESI‐MS, 1D‐ and 2D‐NMR (HMQC, HMBC, 1H,1H‐COSY and NOESY). The antimicrobial activities of 1–8 were evaluated, but none showed any substantial effect.

Chemical constituents of Penicillium chrysogenum, an endophytic fungus from Strychnos toxifera

Strychnos toxifera is a poisonous plant used by Amazon indians in the manufacture of curare poison [1]. Its toxicity is clue to indole alkaloids, which are the major constituents of this poison [2]. Endophytes are considered outstanding and underexplored sources of novel chemically diverse and bioactive compounds. These microorganisms can be detected at a particular moment within the tissues of apparently healthy plant hosts, and they have been found in all plant species examined to date [3]. As they occupy unique biological niches, the complex web of interactions with other endophytes and with the host might give rise to new chemical diversity and bioactive compounds [4]. In the course of screening for biologically active agents from Amazonian endophytic fungi [5], Penicillium chrysogenum, an endophytic fungus from the trunk of S. toxifera, was chosen for further phytochemical investigation. The MeOH extract of the mycelial mass from P. chrysogenum was subjected to chromatographic separation to afford four steroids [6] [ergosterol (1), brassicasterol (2), ergosterol peroxide (3), and cerevisterol (4)], two aromatic acids [7] [cinnamic acid (5) and p-hydroxybenzoic acid (6)], and three mycotoxins [8] [kojic acid (7), penicillic acid (8), and patulin (9)]. These compounds were obtained and characterized by a comparison of their physical and spectral data (UV, IR, NMR and MS), with values in the literature. S. toxifera was collected from Manaus, Brazil in July, 2008. The strain of P. chrysogenum was obtained, purified, and identified from the healthy tissues of the trunk using a previous methodology [9]. After cultivation in liquid media [5], the mycelial mass (1.1 kg) was extracted with MeOH (3 500 mL) at room temperature, and a MeOH extract (30.4 g) was obtained upon concentration under reduced pressure. The MeOH extract was chromatographed over silica gel (600 g, 70–230 mesh) using n-hexane containing increasing amounts of EtOAc to obtain nine fractions. Fraction 1 (321.7 mg) was purified on a silica gel column with n-hexane–CHCl3 with increasing gradient, yielding 1 (22 mg), 2 (7 mg), 3 (12 mg), and 4 (9 mg). Fraction 5 (507 mg) was subjected to silica gel chromatography with CHCl3–MeOH with increasing gradient, yielding 5 (4 mg), 6 (11 mg), 7 (89 mg), 8 (9 mg), and 9 (5 mg).

Bio-Activity and Dereplication-Based Discovery of Ophiobolins and Other Fungal Secondary Metabolites Targeting Leukemia Cells

The purpose of this study was to identify and characterize fungal natural products (NPs) with in vitro bioactivity towards leukemia cells. We based our screening on a combined analytical and bio-guided approach of LC-DAD-HRMS dereplication, explorative solid-phase extraction (E-SPE), and a co-culture platform of CLL and stromal cells. A total of 289 fungal extracts were screened and we tracked the activity to single compounds in seven of the most active extracts. The novel ophiobolin U was isolated together with the known ophiobolins C, H, K as well as 6-epiophiobolins G, K and N from three fungal strains in the Aspergillus section Usti. Ophiobolins A, B, C and K displayed bioactivity towards leukemia cells with induction of apoptosis at nanomolar concentrations. The remaining ophiobolins were mainly inactive or only slightly active at micromolar concentrations. Dereplication of those ophiobolin derivatives possessing different activity in combination with structural analysis allowed a correlation of the chemical structure and conformation with the extent of bioactivity, identifying the hydroxy group at C3 and an aldehyde at C21, as well as the A/B-cis ring structure, as indispensible for the strong activity of the ophiobolins. The known compounds penicillic acid, viridicatumtoxin, calbistrin A, brefeldin A, emestrin A, and neosolaniol monoacetate were identified from the extracts and also found generally cytotoxic.

Type 2 Quorum Sensing Monitoring, Inhibition and Biofilm Formation in Marine Microrganisms

The quorum sensing (QS) dependent behaviour of micro-organisms, in particular expression of virulence genes, biofilm formation and dispersal, have provided impetus for investigating practical approaches to interfere with microbial QS. This study tests Halomonas pacifica and Marinobacter hydrocarbonoclasticus, two halophilic marine micro-organism, for their AI-2 dependent QS signalling and the effect of two well-known quorum-sensing inhibitors (QSIs), patulin and penicillic acid, on biofilm formation. We report, for the first time, the successful amplification of a putative luxS gene in H. pacifica using degenerated primers and AI-2 dependent QS as well as inhibition using QSIs. Penicillic acid had a strong inhibitory effect on AI-2 induction of H. pacifica at non-growth inhibitory concentrations, while patulin has an adverse effect only at the highest concentration (25μM). QSIs effect on biofilm forming capability was isolate specific, with maximum inhibition at 25μM of patulin in H. pacifica. In M. hydrocarbonoclasticus, no adverse effects were noted at any tested concentration of either QSIs. Detection of bioluminescence and the presence of a putative luxS gene provide biochemical and genetic evidence for the production of a signalling molecule(s) which is the essential first step in characterizing H. pacifica QS. This study highlights the importance of AI-2 dependent QS in a marine setting, not previously reported. It further suggests that QSI compounds must be selected in the specific system in which they are to function, and they cannot easily be transferred from one QS system to another.

Exposure to Penicillium mycotoxins alters gene expression of enzymes involved in the epigenetic regulation of bovine macrophages (BoMacs)

In this study, the modulation of key enzymes involved in epigenetic regulation was assessed in immortalized bovine macrophages (BoMacs) following in vitro exposure to the following Penicillium mycotoxins: citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA), penicillic acid (PA), or a combination of one of the above with OTA at the concentration that inhibits BoMac proliferation by 25% (IC25). Real-time PCR analysis of the genes coding DNA methyltransferases (DNMTs), histone demethylases (JMJD-3 and UTX), as well as the class-1 histone deacetylases (HDAC-1, -2, and -3) and histone acetylase (Bmi-1) was assessed following 6 h of mycotoxin exposure. A change in the expression of JMJD-3 as well as HDAC-3, MPA (p = 0.1) and PA (p = 0.08), by at least one of the treatments was observed at their respective IC25. The expression of JMJD-3 was significantly induced by PA, but synergistically suppressed by CIT + OTA. The combination of CIT + OTA also synergistically suppressed the expression of DNMT-3a and DNMT-3b. The combination of PAT + OTA reduced DNMT-3a expression, while PA + OTA reduced DNMT-3b expression. Lastly, MPA and PA slightly reduced HDAC-3 expression, while OTA in combination with CIT, PAT, MPA or PA synergistically suppressed HDAC-3 expression. The results of this study demonstrate that Penicillium mycotoxin exposure, specifically OTA and other mycotoxin combinations, can alter the expression of BoMac enzymes that are involved in epigenetic regulation. These findings suggest a potential novel regulatory mechanism by which mycotoxins can modulate macrophage function.

Cytotoxic metabolites from the cultures of endophytic fungi from Panax ginseng

Two strains of endophytic fungi, Penicillium melinii Yuan-25 and Penicillium janthinellum Yuan-27, with strong anti-Pyricularia oryzae activity, were obtained from the roots of Panax ginseng. Based on bioactivity-oriented isolation, a new benzaldehyde derivative, ginsenocin (1), together with six known compounds, methyl 2,4-dihydroxy-3,5,6-trimethylbenzoate (2), 3,4,5-trimethyl-1,2-benzenediol (3), penicillic acid (4), mannitol (5), ergosterol (6), and ergosterol peroxide (7), were separated from the EtOAc extract of Yuan-25 culture, while brefeldin A (8) was isolated as the major constituent from the EtOAc extract of Yuan-27 culture. The chemical structures were determined based on spectroscopic methods. All the isolated compounds 1-8 were evaluated for their cytotoxicity against six human cancer cell lines. Brefeldin A (8) was the most cytotoxic constituent against all the tested cell lines with IC50 values <0.12μg/ml, while ginsenocin (1) and penicillic acid (4) also exhibited potent cytotoxicity with IC50 values ranging from 0.49 to 7.46μg/ml. Our results suggest that endophytic fungi isolated from P. ginseng are a promising natural source of potential anticancer agents.

Ligerin, an Antiproliferative Chlorinated Sesquiterpenoid from a Marine-Derived Penicillium Strain

A new chlorinated sesquiterpenoid analogue of fumagillin, ligerin (1), was isolated from a marine-derived strain of Penicillium, belonging to the subgenus Penicillium, along with the known compounds penicillic acid (2), orcinol, and orsellinic acid. Chemical structures were established by an interpretation of spectroscopic data including IR, UV, and HRESIMS, together with analyses of 1D and 2D NMR spectra and X-ray analysis for the determination of the absolute configuration. Ligerin (1) displayed strong inhibitory activity against an osteosarcoma cell line. This is the first report of the isolation of a fumagillin analogue from a marine-derived Penicillium strain.

Morphological, molecular, and mycotoxigenic identification of dominant filamentous fungi from moldy civil cheese.

Moldy Civil is a mold-ripened variety of cheese produced mainly in eastern Turkey. This cheese is produced with Civil cheese and whey curd cheese (Lor). Civil cheese has had a geographical presence since 2009 and is manufactured with skim milk. In the production of Moldy Civil cheese, Civil cheese or a mixture of Civil and Lor cheese is pressed into goat skins or plastic bags and ripened for 3 months or longer. During the ripening period, natural contaminating molds grow on the surface of and inside the cheese. In this study, 186 mold strains were isolated from 41 samples of Moldy Civil cheese, and 165 of these strains were identified as Penicillium roqueforti. Identification and mycotoxicologic analyses were conducted using morphotypic and molecular methods. PCR amplicons of the ITS1-5.8S-ITS4 region were subjected to sequence analysis. This research is the first using molecular methods on Moldy Civil cheese. Mycotoxicologic analyses were conducted using thin-layer chromatography, and random amplified polymorphic DNA genotypes were determined using the ari1 primer. Of 165 isolates, only 28 produced no penicillic acid, P. roqueforti toxin, or roquefortine.

Cytotoxic Activity of Fungal Strains Isolated from the Ascidian Eudistoma vannamei

The cytotoxic activity at 50 μg/ml of extracts obtained from eleven fungal strains associated to Eudistoma vannamei, an endemic ascidian from Northeast Brazil, against two cell lines, i.e., the HCT-8 (colon cancer) and the MDA-MB-435 (melanoma) cell lines, was investigated. The most promising extract (EV10) was obtained from a fungus identified as Aspergillus sp. by molecular analysis and was selected for bioassay-guided isolation of its active principals. Large-scale fermentation of EV10 in potato-dextrose broth followed by chromatographic purification of the active extract from the liquid medium allowed the isolation of the isocoumarins mellein, cis-4-hydroxymellein, and trans-4-hydroxymellein, besides penicillic acid. All isolated compounds were tested for their cytotoxicity against the tumor cell lines MDA-MB-435 and HCT-8 and revealed penicillic acid as the only cytotoxic compound (cell growth inhibitions >95%).

Multitoxin evaluation in fermented beverages and cork stoppers by liquid chromatography–tandem mass spectrometry

SummaryA total of twenty‐eight mycotoxins were surveyed in wine (red, white and rose), cider (white and rose) and their cork stoppers from eight countries. Toxins of different fungi genera were detected as follows:Alternaria(ATs: alternariol –AOH; alternariol methyl –AME) andPenicillium/Aspergillus(ochratoxinA–OTA; penicillic acid –PAC). Toxins and levels varied with the sample types and country of origin. Wine presented contamination ofOTA,AOHandAME.OTAwas detected in forty‐one wine samples with levels ranging from 0.01 to 0.86 μg L−1, belowEUlegislation.AOHandAMEwere detected in thirty‐three and eight of wines samples, respectively, at levels from 0.2 to 13.3 μg L−1, while no contamination was detected in ciders up to the methodLOQs. Regarding the cork stoppers toxins detected, they wereAOH,AMEandPAC. Corks of red wine from different countries had levels ofOAHandAMEranging from 5.0 to 101.0 and 2.5 to 5 μg g−1, respectively. It is necessary to pay more attention on the corks processing and cork type used in the bottles as, different from the ordinary ones, the ground bark and compressed type did not have toxins detected.

Immunotoxicity of Penicillium Mycotoxins on Viability and Proliferation of Bovine Macrophage Cell Line (BOMACs)

Penicillium mycotoxins are natural contaminants found in grains, crops, fruits, and fermented products, especially during post harvest as well as storage periods. Contamination by individual and combinations of these toxins is likely to compromise food quality and safety. In this study, the potential immunotoxicity of citrinin (CIT), ochratoxin A (OTA), patulin (PAT), mycophenolic acid (MPA) and penicillic acid (PA) was evaluated using a bovine macrophage cell line (BOMACs) by assessing their potential cytotoxicity and then their effects on cell proliferation. The BOMACs were exposed to a range of mycotoxin concentrations, and then to different mycotoxin combinations for 48 hrs. Some cytotoxicity was evident at concentrations greater than 2.4 � M for PAT, and 160 � M for PA, however, at the IC50 (concentration that inhibits 50% cell proliferation), no cytotoxicity was observed for either of these mycotoxins. The mycotoxin IC50s from most potent to least potent were 0.56 � M (PAT), 12.88 � M (OTA), 29.85 � M (PA), and 91.20 � M (CIT). Concentrations of MPA greater than 80 � M did not inhibit cell proliferation enough to calculate an IC50. Significant higher inhibition of cell proliferation was observed from the combinations of CIT+OTA, OTA+PAT, and OTA+PA compared to the effects of individual mycotoxins suggesting additive and in some cases synergistic activity between these paired mycotoxins.

Mycoflora of Some Smoked Fish Varieties in Benin City Nigeria

A study of the mycoflora of six locally available and commonly consumed dried fish species namely; Ethmalosa fimbriata (bonga fish), Tilapia sp. (Banda mangala) Gadus morhua (stock fish), Pseudotolithus typhus (croaker), Arius hendeloti (cat fish) and Drepane africana (spade fish) was carried out in three sampling regimes. A total of thirty-six samples were randomly sourced from local markets in Benin City and cultured in two replicates per sample per batch in Saboraud dextrose agar (SDA). Six fungal isolates encountered in the study were Aspergillus niger, A. flavus, Penicillium sp, Fusarium sp. Rhizopus sp. and Trichoderma sp. in their order of decreasing frequency in all the fish samples. The highest mean mycoflora count (17.833 x103cfu) was recorded in Tilapia sp., while the lowest mean value (11.16 x103cfu) was recorded in Drepane africana. Aspergillus species are known to produce aflatoxins which are carcinogenic (causing heptoma – cancer of the liver), acute hepatitis, reduced red blood cell and decreased immune system in man. Fusarium sp. is reported to produce fumonisin toxin and Penicillium penicillic acid. Prolonged intake of smoked fish with these metabolites may constitute potential public health hazard. Adequate cooking could help in reducing mycoflora of smoked fish.

Construction of an effective screening system for detection of Pseudomonas aeruginosa quorum sensing inhibitors and its application in bioautographic thin-layer chromatography

In Pseudomonas aeruginosa, quorum sensing (QS) regulates dozens of genes and proteins, many of which contribute to the virulence of this pathogen. QS inhibitory (QSI) compounds have been proposed as potential agents for treatment of bacterial infections. To search for Ps. aeruginosa QS inhibitors, we constructed an effective screening system, QSIS-lasI selector, based on the PlasI-sacB reporter, in which QS could be induced with 20nM 3-oxo-N-[(3S)-tetrahydro-2-oxo-3-furanyl]-dodecanamide (3-oxo-C(12)-HSL). During screening of the crude extracts from 65 marine fungi, an isolate of Penicillium atramentosum was found to have QSI activity. Thin-layer chromatography assay of the fungal extracts for bioautographic identification of QSIS-lasI indicated that this fungus produced several QSI compounds, including QS inhibitors other than penicillic acid or patulin.

Toxigenic microorganisms in medicinal plants used for ritual protection of infants

Plants used as a part of infant protective rituals in some countries of South Eastern Africa and which use has been associated to food poisoning episodes were submitted to a microbiological analysis to investigate potential microbiological hazards. This characterization led to the detection of a high load of moulds and aerobic spore-formers microorganisms. Isolates of Bacillus cereus and Bacillus thuringiensis were observed to contained different toxin-encoding genes, and the production of diarrheal enterotoxin was confirmed in some of them. The production of aflatoxin B1 and cyclopiazonic acid by strains of Aspergillus flavus, and citrinin and penicillic acid by Penicillium citrinum was revealed by HPLC. The toxicity of these isolates was also showed by the Artemia salina lethality test. The results indicate the presence of microorganisms with toxigenic potential in plants used as folk medicine in South Eastern Africa. The traditional use of these preparations should be carefully reconsidered due to the microbiological risks associated with their ingestion.