Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro

Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.

The Influence of Long-Term Storage on the Epiphytic Microbiome of Postharvest Apples and on Penicillium expansum Occurrence and Patulin Accumulation

Patulin is a secondary metabolite primarily synthesized by the fungus Penicillium expansum, which is responsible for blue mold disease on apples. The latter are highly susceptible to fungal infection in the postharvest stages. Apples destined to produce compotes are processed throughout the year, which implies that long periods of storage are required under controlled atmospheres. P. expansum is capable of infecting apples throughout the whole process, and patulin can be detected in the end-product. In the present study, 455 apples (organically and conventionally grown), destined to produce compotes, of the variety "Golden Delicious" were sampled at multiple postharvest steps. The apple samples were analyzed for their patulin content and P. expansum was quantified using real-time PCR. The patulin results showed no significant differences between the two cultivation techniques; however, two critical control points were identified: the long-term storage and the deck storage of apples at ambient temperature before transport. Additionally, alterations in the epiphytic microbiota of both fungi and bacteria throughout various steps were investigated through the application of a metabarcoding approach. The alpha and beta diversity analysis highlighted the effect of long-term storage, causing an increase in the bacterial and fungal diversity on apples, and showed significant differences in the microbial communities during the different postharvest steps. The different network analyses demonstrated intra-species relationships. Multiple pairs of fungal and bacterial competitive relationships were observed. Positive interactions were also observed between P. expansum and multiple fungal and bacterial species. These network analyses provide a basis for further fungal and bacterial interaction analyses for fruit disease biocontrol.

Impacts of abiotic factors on the growth of three commercial biological control agents, on the growth and mycotoxinogenesis of Fusarium graminearum and on their interaction

BACKGROUND

Evolving climatic conditions impact the behavior of microorganisms. The lack of efficiency of beneficial microorganisms against pathogens can be due to these evolving abiotic factors more favorable to the development and adaptation of pathogens. It is therefore of great interest to understand their impact (especially temperature increase and relative humidity (RH) variation) on pathogenic and non-pathogenic microorganisms. This work aimed to examine the possible effects of increasing temperature (20, 25, 30 and 33 °C) and RH (40%, 50%, 60% and 80%) on the growth and mycotoxin production (deoxynivalenol (DON) and zearalenone (ZEN)) of Fusarium graminearum, on the growth of three commercial biocontrol agents (BCAs; Mycostop®, Xedavir® and Polyversum®) and on the pathogen-BCA interaction.

RESULTS

Results demonstrated that BCAs have contrasting impacts on the growth and mycotoxinogenesis of F. graminearum depending on abiotic factors. At 25 °C and regardless of RH, commercial BCAs limit DON production by F. graminearum, but at 30 °C and intermediate RH, Xedavir® is no longer effective. The ability of Xedavir® to control the production of ZEN production by F. graminearum is also affected by abiotic factors. However, increasing temperature has an opposite effect on its ability to control the accumulation of ZEN. Polyversum® oomycete is the BCA with the most resilient efficacy against F. graminearum toxinogenesis under the different abiotic factors.

CONCLUSION

This work provides new knowledge of the effect of these abiotic parameters on the interaction between BCA and F. graminearum, especially on the production of mycotoxins. It paves the way for the development of efficient and resilient mycotoxin biocontrol strategies using beneficial microorganisms against F. graminearum, thus contributing to global food security. © 2023 Society of Chemical Industry.

Inhibition of Aspergillus carbonarius growth and Ochratoxin A production using lactic acid bacteria cultivated in an optimized medium

The Gram-positive bacteria lactic acid bacteria (LAB) are used in the food industry but are also known for inhibiting certain food spoilage microorganisms, especially fungi. Sources of nitrogen (N) for culture media are generally organic and expensive. Many attempts have been made to formulate economical culture media with alternative N sources obtained from agricultural and industrial byproducts. This study describes the design and optimization of an inexpensive culture medium for Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) MZ809351 strain B31. The culture medium was optimized using statistical experimental designs to identify the factors with the most significant effects on biomass concentration to reduce the overall cost, aiming to obtain a biomass concentration similar to that obtained with the reference LAB culture medium (de Man, Rogosa and Sharpe; MRS). Sodium acetate and magnesium sulfate were the most significant factors (p < 0.005), and their contents were reduced by 22 % and 40 %, respectively, without affecting biomass concentration. Malt germ extract (MGE) was used as an alternative nitrogen source to replace meat extract (ME) and proteose peptone (PP). Through these experiments, the composition of a culture medium that is less expensive than MRS broth was defined, which produced a biomass concentration (3.8 g/L) similar to that obtained with MRS medium. The inhibitory effects of two LAB strains isolated from the Ivory Coast and Mexico on the growth and production of ochratoxin A (OTA) in an ochratoxigenic fungus was tested. The minimum cellular concentration of the LAB to prevent the development of Aspergillus carbonarius Ac 089 and the production of OTA was determined in a model assay in Petri dishes. The conditions to inhibit the germination of A. carbonarius Ac 089 and the production of OTA were found. Using the optimized medium and a ratio of 2 × 104 LAB/spore (1 × 108 CFU/mL) strain B7 (L. plantarum MZ809351) and 2 × 103 LAB/spore (1 × 107 CFU/mL) strain B31 (L. plantarum MN922335) completely inhibited the growth of the fungus. A ratio of 2 × 105 LAB/spore (1 × 109 CFU/mL) was required to inhibit OTA production with strains B7 and B31. This study indicates the potential of cultivating LAB in an optimized and inexpensive culture medium for use as a biological control agent against ochratoxigenic fungi in food.

Biocontrol Agents: Toolbox for the Screening of Weapons against Mycotoxigenic Fusarium

The aim of this study was to develop a set of experiments to screen and decipher the mechanisms of biocontrol agents (BCAs), isolated from commercial formulation, against two major mycotoxigenic fungi in cereals, Fusarium graminearum and Fusarium verticillioides. These two phytopathogens produce mycotoxins harmful to human and animal health and are responsible for the massive use of pesticides, for the protection of cereals. It is therefore essential to better understand the mechanisms of action of alternative control strategies such as the use of BCAs in order to optimize their applications. The early and late stages of interaction between BCAs and pathogens were investigated from germination of spores to the effects on perithecia (survival form of pathogen). The analysis of antagonist activities of BCAs revealed different strategies of biocontrol where chronological, process combination and specialization aspects of interactions are discussed. Streptomyces griseoviridis main strategy is based on antibiosis with the secretion of several compounds with anti-fungal and anti-germination activity, but also a mixture of hydrolytic enzymes to attack pathogens, which compensates for an important deficit in terms of spatial colonization capacity. It has good abilities in terms of nutritional competition. Trichoderma asperellum is capable of activating a very wide range of defenses and attacks combining the synthesis of various antifungal compounds (metabolite, enzymes, VOCs), with different targets (spores, mycelium, mycotoxins), and direct action by mycoparasitism and mycophagy. Concerning Pythium oligandrum, its efficiency is mainly due to its strong capacity to colonize the environment, with a direct action via microbial predation, stimulation of its reproduction at the contact of pathogens and the reduction of perithecia formation.

Aspergillus flavus Growth Inhibition and Aflatoxin B1 Decontamination by Streptomyces Isolates and Their Metabolites

Aflatoxin B₁ is a potent carcinogen produced by Aspergillus flavus, mainly during grain storage. As pre-harvest methods are insufficient to avoid mycotoxin presence during storage, diverse curative techniques are being investigated for the inhibition of fungal growth and aflatoxin detoxification. Streptomyces spp. represent an alternative as they are a promising source of detoxifying enzymes. Fifty-nine Streptomyces isolates and a Streptomyces griseoviridis strain from the commercial product Mycostop^®, evaluated against Penicillium verrucosum and ochratoxin A during previous work, were screened for their ability to inhibit Aspergillus flavus growth and decrease the aflatoxin amount. The activities of bacterial cells and cell-free extracts (CFEs) from liquid cultures were also evaluated. Fifty-eight isolates were able to inhibit fungal growth during dual culture assays, with a maximal reduction going down to 13% of the control. Aflatoxin-specific production was decreased by all isolates to at least 54% of the control. CFEs were less effective in decreasing fungal growth (down to 40% and 55% for unheated and heated CFEs, respectively) and aflatoxin-specific production, with a few CFEs causing an overproduction of mycotoxins. Nearly all Streptomyces isolates were able to degrade AFB₁ when growing in solid and liquid media. A total degradation of AFB₁ was achieved by Mycostop^® on solid medium, as well as an almost complete degradation by IX20 in liquid medium (6% of the control). CFE maximal degradation went down to 37% of the control for isolate IX09. The search for degradation by-products indicated the presence of a few unknown molecules. The evaluation of residual toxicity of the tested isolates by the SOS chromotest indicated a detoxification of at least 68% of AFB₁’s genotoxicity.

Microbiome Status of Cider-Apples, from Orchard to Processing, with a Special Focus on Penicillium expansum Occurrence and Patulin Contamination

Patulin is a secondary metabolite produced primarily by the fungus Penicillium expansum, responsible for the blue mold disease on apples. It is found in apple products including apple cider when apple juice is added after fermentation. In the present study, two hundred and twenty-five cider-apples of the variety “Bedan”, cultivated in Brittany in France, were sampled from the orchard during harvesting until the storage step, right before processing. The patulin analysis on these samples reported a low contamination at the orchard and a significantly higher-level of contamination in the cider-apples starting from the transporting bin. The percentage of positive samples increased from 6% to 47% after 12 h in the harvesting bin before transporting and reached 95% after 24 h of transporting, decreasing then to 69% at the end of the storage. Penicillium expansum was quantified on the surface of apples using real-time PCR and was observed to be mostly consistent between the harvest and post-harvest steps. It was detected on average, on the surface of 85% of all sampled apples with a mean value around 2.35 × 10⁶Penicillium expansum DNA/g of apple. Moreover, the changes in the fungal and bacterial epiphytic microbiota in the different steps were studied using a metabarcoding approach. The alpha and beta diversity analysis revealed the presence of unique and more diverse bacterial and fungal communities on the surface of apples picked from the orchard compared to the rest of the sampling steps. Potential indigenous biological control agents were identified on the surface of sampled apples. Future perspective includes developing actions of prevention and control of the contamination by Penicillium expansum during the harvest and along the various critical post-harvest stages before transformation in a sustainable development concern.

Transcriptomes of the interaction between Fusarium verticillioides and a Streptomyces strain reveal the fungal defense strategy under the pressure of a potential biocontrol agent

The actinobacteria Streptomyces sp. AV05 appears to be a potential biocontrol agent (BCA) against mycotoxigenic fungi. It was found to significantly inhibit F. verticillioides growth and mycotoxin production during their co-cultivation. F. verticillioides growth was durably affected while the decrease of the toxin production levels was reversible, suggesting different BCA actions. The study of both transcriptomes brought useful information on the microbial interaction. RNA-seq data indicated that the dual interaction modified genetic expression of both microorganisms as 18.5 % of the genes were differentially expressed for the fungus against 3.8 % for the actinobacteria. Fungal differentially expressed genes (DEGs) were equally up and down regulated while bacterial ones were mainly upregulated. We especially focused the analysis of DEGs on fungal defense reaction to bacterial attack. For example, if this potential BCA implements a strategy of antibiosis with the over expression of 'siderophore-interacting protein' linked to the production of bacteriocins, the fungus in a state of stress is able to adapt its metabolism by up-regulation of amidase. It could correspond to the induction of resistance gene clusters and suggest a detoxification process. Moreover fumonisins-related pathway appears underexpressed in the presence of Streptomyces that explain the reduction of fumonisin accumulation observed.

Differentiation and quantification of the ochratoxin A producers Aspergillus ochraceus and Aspergillus westerdijkiae using PCR-DGGE

Ochratoxin A (OTA) is a nephrotoxic, teratogenic, immunotoxic, and carcinogenic mycotoxin which is produced in tropical zones mainly by Aspergillus carbonarius, A. niger, A. ochraceus, and A. westerdijkiae. A. ochraceus and A. westerdijkiae species are phenotypically and genomically very close but A. westerdijkiae produce OTA at a very higher level than A. ochraceus. These species have been differentiated recently. The DNA primer pairs which were drawn so far are not specific and a genomic region of the same size is amplified for both species or they are too specific, and in this case, the DNA of a single species is amplified. To help preventing OTA contamination of foodstuffs, the PCR-DGGE (Denaturing Gradient Gel Electrophoresis) method was used to discriminate between A. ochraceus and A. westerdijkiae DNA fragments of the same size but with different sequences and thus faster access to a diagnosis of the toxigenic potential of the fungal microflora. The proposed methodology was able to differentiate A. westerdijkiae from A. ochraceus with only one primer pairs in a single run. A calibration based on initial DNA content was obtained from image analysis of the DGGE gels and a method of quantification of the two strains was proposed.

Microbiological safety of flours used in follow up for infant formulas produced in Ouagadougou, Burkina Faso

The prevalence of diarrheal diseases in children aged from 6 to 24 months in Burkina Faso is 38%. These diarrheas may be due to the consumption of contaminated weaning food. Therefore, the microbiological quality of follow up infant flours used as supplement foods is a key-point to reduce children diseases. In this study, the microbiological safety of locally-produced infant flours was investigated. One hundred and ninety-nine (199) samples were collected mainly in retails outlets and in Recovery and Nutrition Education Centers. According to the Burkina Faso regulations, microbiological analyses were carried out for Total Aerobic Mesophilic Flora (TAMF), thermotolerant coliforms, Salmonella spp. and yeasts/molds. The bacterial and fungal isolates were identified using phenotypic and genotypic methods and the study of the production of mycotoxins was carried out from the fungal isolates. In collected samples, the TAMF count ranged from 0 to 1.8 × 10⁶ CFU/g with a total average of 6.3 × 10⁴ CFU/g. About 2% of the samples had a microbial load exceeding the standards (10⁵ CFU/g). No Salmonella spp. was isolated in the final infant flours. However, the presence of Enterobacteriaceae (Klebsiella spp. Enterobacter spp. and Cronobacter spp.) was detected and molecular characterization revealed also the presence of fungal species of the genus Aspergillus spp., Penicillium spp. and Fusarium spp. Some of these species were found to produce aflatoxins, ochratoxin A and fumonisins, which are potential carcinogenic toxins. These results demonstrated the need for a preventive approach based on the application of Hazard Analysis Critical Control Point in the food industry to ensure food safety of infant flours in Burkina Faso.

Evidence for a role of oestrogen receptor-related receptor in the regulation of male sexual behaviour in the moth Agrotis ipsilon

The oestrogen receptor-related receptors (ERRs) are orphan nuclear receptors that were originally identified on the basis of their close homology to the oestrogen receptors. The three mammalian ERR genes participate in the regulation of vital physiological processes including reproduction, development and metabolic homeostasis. Although unique ERRs have been found in insects, data on the function and regulation of these receptors remain sparse. In the present study, a 2095-bp full-length cDNA encoding an ERR, termed AiERR, was isolated from males of the moth Agrotis ipsilon and deposited in the GenBank database under the accession number KT944662. The predicted AiERR protein shared an overall identity of 47-82% with other known insect and mammalian ERR homologues. AiERR exhibited a broad tissue expression pattern with the detection of one transcript of approximately 2 kb in the primary olfactory centres, the antennal lobes (AL). In adult males, the amount of AiERR mRNA in the AL increased concomitantly with age and responses to the female-emitted sex pheromone. Moreover, AiERR knockdown induced an inhibition in the sex pheromone-orientated flight of male. Using A. ipsilon as a model, our study demonstrates that the insect ERR is critical for the performance of male sexual behaviour, probably by acting on central pheromone processing.

Effect of post-harvest treatments on the occurrence of ochratoxin A in raw cocoa beans

Cocoa beans are the principal raw material for chocolate manufacture. Moulds have an important place in the change in the quality of cocoa beans due to their role in the production of free fatty acids and mycotoxins, namely ochratoxin A (OTA). This study investigated the impact of the key post-harvest treatments, namely the fermentation and drying methods on OTA contamination of raw cocoa beans. Analytical methods for OTA detection were based on solid-liquid extraction, clean-up using an immunoaffinity column, and identification by reversed-phase HPLC with fluorescence detection. Of a total of 104 randomly selected cocoa samples analysed, 32% had OTA contents above 2 µg kg(-1). Cocoa sourced from pods in a bad state of health had a maximum OTA content of 39.2 µg kg(-1), while that obtained from healthy pods recorded 11.2 µg kg(-1). The production of OTA in cocoa beans increased according to the pod-opening delay and reached 39.2 µg kg(-1) after an opening delay of 7 days after harvest, while 6.1 and 11.2 µg kg(-1) were observed when pods were opened after 0 and 4 days. OTA production also seemed to depend considerably to the cocoa fermentation materials. When using plastic boxes for bean fermentation, the OTA production was enhanced and reached an average OTA content of about 4.9 µg kg(-1), while the raw cocoa treated in banana leaves and wooden boxes recorded 1.6 and 2.2 µg kg(-1) on average respectively. In parallel, the OTA production was not really influenced by either the mixing or the duration of the fermentation or the drying materials.

Antennal uridine diphosphate (UDP)-glycosyltransferases in a pest insect: diversity and putative function in odorant and xenobiotics clearance

Uridine diphosphate UDP-glycosyltransferases (UGTs) are detoxification enzymes widely distributed within living organisms. They are involved in the biotransformation of various lipophilic endogenous compounds and xenobiotics, including odorants. Several UGTs have been reported in the olfactory organs of mammals and involved in olfactory processing and detoxification within the olfactory mucosa but, in insects, this enzyme family is still poorly studied. Despite recent transcriptomic analyses, the diversity of antennal UGTs in insects has not been investigated. To date, only three UGT cDNAs have been shown to be expressed in insect olfactory organs. In the present study, we report the identification of eleven putative UGTs expressed in the antennae of the model pest insect Spodoptera littoralis. Phylogenetic analysis revealed that these UGTs belong to five different families, highlighting their structural diversity. In addition, two genes, UGT40R3 and UGT46A6, were either specifically expressed or overexpressed in the antennae, suggesting specific roles in this sensory organ. Exposure of male moths to the sex pheromone and to a plant odorant differentially downregulated the transcription levels of these two genes, revealing for the first time the regulation of insect UGTs by odorant exposure. Moreover, the specific antennal gene UGT46A6 was upregulated by insecticide topical application on antennae, suggesting its role in the protection of the olfactory organ towards xenobiotics. This work highlights the structural and functional diversity of UGTs within this highly specialized tissue.

Adenoid cystic carcinoma of the paranasal sinuses: retrospective series and review of the literature

OBJECTIVES

Adenoid cystic carcinomas (ACC) are rare malignant tumours arising in the major and minor salivary glands. Involvement of the nasal cavity and paranasal sinuses is rare and poorly described. The purpose of this study was to define the clinical and prognostic criteria of ACC of the paranasal sinuses based on the review of a series of 25 cases.

MATERIAL AND METHODS

Single-centre retrospective study of 25 cases of ACC of the paranasal sinuses managed between 1998 and 2011, evaluating epidemiological, clinical, diagnostic and prognostic criteria. Factors influencing survival (Kaplan-Meier/Log Rank test) and the patient's quality of life (EORTC QLQ-C30 questionnaire) were also analysed.

RESULTS

Most patients (72%) had a locally-advanced tumour (stage T3 or T4) at diagnosis. Tumour sites, in decreasing order of frequency, were the maxillary sinus, nasal cavities and ethmoid sinus. The most common presenting complaints were maxillary pain or heaviness, unilateral blocked nose, and repeated epistaxis. When the tumour was resectable, treatment comprised a combination of surgery and adjuvant radiotherapy. The 5-year overall survival rate was 63% and the 5-year disease-free survival rate was 43%. The TNM stage at diagnosis (P=0.03), the histological subtype (P=0.023), the possibility of combined surgery and radiotherapy (P=0.03), and local control (P=0.05) were significant factors of improved 5-year overall survival. Positive surgical margins were associated with a trend towards poorer 5-year disease-free survival (ns).

CONCLUSIONS

ACC are rare malignant tumours associated with a poor prognosis, characterized by a high recurrence rate. Recommended treatment is a combination of surgery and adjuvant radiotherapy whenever possible. Five-year survival varies as a function of TNM stage, histological subtype, treatment options and local control.

Synchronous bilateral acinic cell carcinoma of the parotid: when a tumor reveals another one

INTRODUCTION

Acinic cell carcinoma is a rare form (2-4%) of parotid tumor. It is, however, the most frequent form of bilateral parotid tumor and the second most frequent form in children.

CASE REPORT

A 22-year-old man had several years' history of left parotid tumor, discovered to be acinic cell carcinoma. MRI found a synchronous contralateral tumor of the same histologic nature.

DISCUSSION/CONCLUSION

This case highlights the need for rigorous examination of the contralateral parotid in case of parotid tumor and especially of acinic cell carcinoma.

[Parapharyngeal tumors: management and postoperative results]

OBJECTIVES

Parapharyngeal space tumours are rare and mostly benign, and their access is difficult. The aim of the study was to define the optimal treatment of these tumours.

MATERIAL AND METHODS

Clinical retrospective study, with histological, treatment, prognosis analysis of the parapharyngeal space tumours occurred between 1994 and 2012 and the surgical approach considerations.

RESULTS

35 patients were included with a male sex ratio predominance (51.43%, p = ns). The mean age of diagnosis was 49 years. The majority of tumours were benign (75.76%, p < 0.001). 54.5% originated from salivary gland with a majority of pleomorphic adenomas (42.42%). The second most frequent aetiology found was schwannoma (21.21%). 2 patients refused the treatment. Accidentally discovered were frequent (28.57%). In the symptomatic forms, dysphagia dominated (25.71%). Oropharyngeal (20%) and/or cervical (17.14%) mass were rare. A CT scan and a MR imaging were performed in 82.86% and 71.43% of the cases. A fine needle aspiration cytology was achieved in 10 cases with a positive predictive value of 60%. The cervical submandibular trans digastric approach was the most accomplished (40%). Other approaches were also used: Trans oral (25.71%), parotidectomy (14.71%), combined trans oral and cervical or parotidectomy (14.71%) and the cervical approached associated to a mandibulotomy (5.71%). A complementary treatment was proposed in 85.7% of the cases of malignant tumours. Post-operative complications were dominated by Horner's syndrome (n = 3), a temporary facial palsy (n = 5), definitive (n = 1), a velar insufficiency (n = 1), persistent pain (n = 6).

CONCLUSIONS

The presence of 25% of malignant tumours and 40% of pleomorphic adenomas require removal of parapharyngeal tumours, even if non symptomatic.

Influence of post-harvest processing on ochratoxin A content in cocoa and on consumer exposure in Cameroon

Ochratoxin A (OTA) is a mycotoxin that contaminates several foodstuffs, including cocoa. It has nephrotoxic, teratogenic and carcinogenic properties in humans. The effect of post-harvest processing and storage on the OTA contamination of cocoa was studied over three successive cocoa seasons (2005, 2006 and 2007) in Cameroon. The type of fermentation (box or heap) did not significantly influence bean OTA content, which varied from undetectable (<0.03 ng/g) to 0.25 ng/g, remaining below 2 ng/g (the defined standard for cocoa beans). However, pod damage and late pod opening were aggravating factors for OTA contamination of cocoa. If pods were not intact (intentionally or naturally damaged), OTA was found in samples with contents of up to 75.5 ng/g before processing and 32.2 ng/g after 4 months' storage. This contamination exceeded the levels tolerated for export. In addition, some of the cocoa produced is processed locally and consumed as chocolate, cocoa powder, chocolate filled sweets, cocoa-based drinks and cocoa butter. In Cameroon, the average daily consumption of cocoa by-products is estimated at 0.75 g/d for adults and 1 g/d for children. Consequently, for maximum OTA contamination of cocoa beans, the maximum daily exposure to OTA would be 1.61 ng/kg bw/d in young children weighing around 20 kg, greatly contributing to the exposure of young consumers.

A diversity of putative carboxylesterases are expressed in the antennae of the noctuid moth Spodoptera littoralis

Recent studies have suggested that pheromone-degrading enzymes belonging to the carboxylesterase family could play a role in the dynamics of the olfactory response to acetate sex pheromones in insects. Bioinformatic analyses of a male antennal expressed sequence tag library allowed the identification of 19 putative esterase genes expressed in the antennae of the moth Spodoptera littoralis. Phylogenetic analysis revealed that these genes belong to different insect esterase clades, defined by their putative cellular localization and substrate preferences. Interestingly, two of the 19 genes appeared to be antennal specific, suggesting a specific role in olfactory processing. This high esterase diversity suggested that the antennae are the location for intense esterase-based metabolism, against potentially a large range of exogenous and endogenous molecules.

[Congenital cyst and fistula of the face and neck]

The authors propose an update on cervicofacial congenital cysts and fistulas' symptomatology. Embryological data, epidemiology and clinical manifestations are described. A reminder of the therapeutic principles is proposed as well as the evolution of these congenital pathologies, which may or may not involve the branchial system. branchial.

Effect of operating conditions on ochratoxin A extraction from roasted coffee

Operating conditions affect ochratoxin A (OTA) extraction from roasted coffee. The OTA content found in the beverage can thus be greater than that found in the roasted coffee used to prepare it. Three extraction parameters were studied for roasted coffee: type of extraction solvent (alkaline, neutral, acid), temperature (ambient temperature/23 degrees C, 60 degrees C and 85 degrees C), and extraction time (5, 20, 30, 40, 50, 60 and 80 min). The alkaline solvent used in the method recommended by the European Union extracted OTA better, but a maximum content was obtained at 60 degrees C after 50 min. At least a 100% improvement in extraction was obtained when compared with the European Union usual quantification method that is carried out at ambient temperature. It turned out that the OTA extraction parameters for roasted coffee, as defined by that method, were not optimum and needed to be modified. These results were verified in double-extraction experiments showing that OTA is not completely extracted by this method. Confirmation was obtained by comparison of extraction methods on several commercial samples of roasted coffee.

A conserved acidic motif in the N-terminal domain of nitrate reductase is necessary for the inactivation of the enzyme in the dark by phosphorylation and 14-3-3 binding

It has previously been shown that the N-terminal domain of tobacco (Nicotiana tabacum) nitrate reductase (NR) is involved in the inactivation of the enzyme by phosphorylation, which occurs in the dark (L. Nussaume, M. Vincentz, C. Meyer, J.P. Boutin, and M. Caboche [1995] Plant Cell 7: 611-621). The activity of a mutant NR protein lacking this N-terminal domain was no longer regulated by light-dark transitions. In this study smaller deletions were performed in the N-terminal domain of tobacco NR that removed protein motifs conserved among higher plant NRs. The resulting truncated NR-coding sequences were then fused to the cauliflower mosaic virus 35S RNA promoter and introduced in NR-deficient mutants of the closely related species Nicotiana plumbaginifolia. We found that the deletion of a conserved stretch of acidic residues led to an active NR protein that was more thermosensitive than the wild-type enzyme, but it was relatively insensitive to the inactivation by phosphorylation in the dark. Therefore, the removal of this acidic stretch seems to have the same effects on NR activation state as the deletion of the N-terminal domain. A hypothetical explanation for these observations is that a specific factor that impedes inactivation remains bound to the truncated enzyme. A synthetic peptide derived from this acidic protein motif was also found to be a good substrate for casein kinase II.

Randomly amplified polymorphic DNAs assess recombination following an induced parasexual cycle in Penicillium roqueforti

Random amplified polymorphic DNAs (RAPDs) were used as a genetic marker system to characterize recombinant strains following the parasexual cycle of Penicillium roqueforti. After protoplast fusion and haploidization of diploid hybrids, segregants characterized by a reassortment of the parental genetic markers displayed specific RAPD fingerprints. The appearance or the loss of RAPD fragments demonstrate that these markers provide an efficient method to analyze recombination and to characterize somatic hybrids.

Immunostaining of a cell type in the islets of Langerhans of the monkey Macaca irus by antibodies against S-100 protein

S-100 protein-immunoreactive cells were demonstrated by immunocytochemical procedures in the pancreatic islets of Langerhans in the monkey Macaca irus. By use of antibodies against human S-100 protein or bovine S-100 protein, these cells were observed in all islets in the head and tail portions of the pancreas. Immunostained cells were usually located in the center of the islets or sometimes found in a more widely distributed form, but they were never arranged in a regular concentric fashion. The number of immunoreactive cells varied from one islet to another but it was relatively limited making up only 0.75%-6.3% of all insular cells. With the use of the double-immunoenzymatic procedure for demonstration of the four main endocrine cell types (insulin-, glucagon-, somatostatin- and pancreatic polypeptide producing elements), it was possible to establish that S-100 protein-immunoreactive cells represent a distinct cell type. Antibodies against S-100 protein-stained neuroinsular complexes. The present findings speak in favor of a new cell type to be added to the large variety of S-100 protein-immunoreactive cells outside the central nervous system.

Immunocytochemical localization of S-100 protein in interstitial cells of the monkey Macaca irus pineal gland

Pineal interstitial cells of the monkey Macaca irus were shown to react with an anti-human S-100 protein antibody, using the indirect immunoperoxidase technique on sections of paraplast-embedded pineal glands. Immunoreactivity was seen in the cytoplasm of the cells, stellate in shape and intermingled with pinealocytes; the latter did not stain with the antiserum against S-100 protein. Immunoreactivity was also present in the nuclei, as was reported in various other cell types immunostained with anti-S-100 protein antibodies. The present results support the view that interstitial cells of the monkey Macaca irus pineal gland may be of astroglial origin.