Prediction and experimental evidence of the optimisation of the angular branching process in the thallus growth of Podospora anserina

Based upon apical growth and hyphal branching, the two main processes that drive the growth pattern of a fungal network, we propose here a two-dimensions simulation based on a binary-tree modelling allowing us to extract the main characteristics of a generic thallus growth. In particular, we showed that, in a homogeneous environment, the fungal growth can be optimized for exploration and exploitation of its surroundings with a specific angular distribution of apical branching. Two complementary methods of extracting angle values have been used to confront the result of the simulation with experimental data obtained from the thallus growth of the saprophytic filamentous fungus Podospora anserina. Finally, we propose here a validated model that, while being computationally low-cost, is powerful enough to test quickly multiple conditions and constraints. It will allow in future works to deepen the characterization of the growth dynamic of fungal network, in addition to laboratory experiments, that could be sometimes expensive, tedious or of limited scope.Comment: Submitted to Scientific Repor

Isolation and Identification of Antibiotic-Producing Halophilic Bacteria from Dagh Biarjmand and Haj Aligholi Salt Deserts, Iran

Background: Halophilic bacteria are potent organisms in production of novel bioactive antimicrobial compounds which might be considered in drug innovation and control of plant pathogens. Salt deserts in Semnan province are of the most permanent hypersaline areas in the North of Iran. Despite the importance of these areas, there is no scientific report regarding the biodiversity and potency of their halophilic bacteria. Thus, aforementioned areas were selected to detect the halophilic bacteria. Methods: Here, seven strains were isolated and cultured on their molecular and biochemical properties were characterized. To determine the antibiotic potency of the isolates, agar well diffusion method was conducted. Phylogenetic analysis was done to reveal the isolates relationship with previously known strains. Results: As a result, growth of the strains in the medium containing 5 to 20% (w/v) NaCl determined that the majority of the isolates were moderately halophile. Catalase activity of all strains was positive. The results represented that D6A, Dar and D8B have antimicrobial effects against different plant and human pathogens. Phylogenic tree analysis also showed that two strains of D6A and Dar are belonged to Bacillus subtilis and D8B is belonged to Virgibacillus olivae. The bacteria extracts were evaluated for their antifungal and antibacterial activities on human and Plant pathogenic strains. The MIC of the extract B. subtilis against was found active against human pathogenic fungi and Plant pathogenic bacteria and fungi, ranging from 12.5 to 25 µg/mL. Conclusion: This study highlights the therapeutic and prophylactic potential of B. subtilis extracts as antibacterial and antifungal agents

Hyphal network whole field imaging allows for accurate estimation of anastomosis rates and branching dynamics of the filamentous fungus Podospora anserina

The success of filamentous fungi in colonizing most natural environments can be largely attributed to their ability to form an expanding interconnected network, the mycelium, or thallus, constituted by a collection of hyphal apexes in motion producing hyphae and subject to branching and fusion. In this work, we characterize the hyphal network expansion and the structure of the fungus Podospora anserina under controlled culture conditions. To this end, temporal series of pictures of the network dynamics are produced, starting from germinating ascospores and ending when the network reaches a few centimeters width, with a typical image resolution of several micrometers. The completely automated image reconstruction steps allow an easy post-processing and a quantitative analysis of the dynamics. The main features of the evolution of the hyphal network, such as the total length L of the mycelium, the number of "nodes" (or crossing points) N and the number of apexes A, can then be precisely quantified. Beyond these main features, the determination of the distribution of the intra-thallus surfaces (S; i; ) and the statistical analysis of some local measures of N, A and L give new insights on the dynamics of expanding fungal networks. Based on these results, we now aim at developing robust and versatile discrete/continuous mathematical models to further understand the key mechanisms driving the development of the fungus thallus

Multilocus microsatellite analysis of European and African Candida glabrata isolates

This study aimed to elucidate the genetic relatedness and epidemiology of 127 clinical and environmental Candida glabrata isolates from Europe and Africa using multilocus microsatellite analysis. Each isolate was first identified using phenotypic and molecular methods and subsequently, six unlinked microsatellite loci were analyzed using automated fluorescent genotyping. Genetic relationships were estimated using the minimum-spanning tree (MStree) method. Microsatellite analyses revealed the existence of 47 different genotypes. The fungal population showed an irregular distribution owing to the over-representation of genetically different infectious haplotypes. The most common genotype was MG-9, which was frequently found in both European and African isolates. In conclusion, the data reported here emphasize the role of specific C. glabrata genotypes in human infections for at least some decades and highlight the widespread distribution of some isolates, which seem to be more able to cause disease than others.This research was supported in part by the EU Mare Nostrum (EUMN-III Call) program of the European Union, grant agreement number 2011-4050/001-EMA2. Dr Sanae Rharmitt was the recipient of a scholarship (10 months) signed within the EUMN program for PhD students (F.S. 1.04.11.01 UORI) under the supervision of Prof Orazio Romeo.info:eu-repo/semantics/publishedVersio

Phytothérapie antilithiasique urinaire

PARIS-BIUP (751062107) / SudocSudocFranceF

Utilisation traditionnelle des plantes à visée antidiabétique sur l'Ile de La Réunion

PARIS-BIUP (751062107) / SudocSudocFranceF

Les phycocolloïdes en cuisine moléculaire

PARIS-BIUP (751062107) / SudocSudocFranceF

Les mycotoxines dans le vin et le café (cas de l'ochratoxine A)

PARIS-BIUP (751062107) / SudocSudocFranceF

ETUDE DE LA RESISTANCE AUX ANILINOPYRIMIDINES ET A D'AUTRES FONGICIDES CHEZ LE CHAMPIGNON PHYTOPATHOGENE BOTRYTIS CINEREA

BOTRYTIS CINEREA, AGENT DE LA POURRITURE GRISE, CAUSE DES PERTES IMPORTANTES DANS LES VIGNOBLES. LA GESTION DES RISQUES DE RESISTANCE NECESSITE D'Y CARACTERISER LES DIFFERENTS PHENOTYPES DE RESISTANCE VIS-A-VIS DES FONGICIDES ET DE COMPRENDRE LES MECANISMES IMPLIQUES. NOUS AVONS CONFIRME LA PRESENCE DE 2 PHENOTYPES DE RESISTANCE AUX BENZIMIDAZOLES, L'UN EST SENSIBLE AUX PHENYLCARBAMATES ET L'AUTRE RESISTANT, ET D'UN PHENOTYPE DE RESISTANCE AUX DICARBOXIMIDES. LE DETERMINISME GENETIQUE DE CHAQUE PHENOTYPE EST MONOGENIQUE. NOUS AVONS CARACTERISE UN PHENOTYPE DE RESISTANCE AU FENHEXAMID, DONT LE DETERMINISME GENETIQUE N'A PU ETRE ETUDIE FAUTE DE CROISEMENTS FERTILES, ET UN PHENOTYPE DE SENSIBILITE AU CYMOXANIL, DONT LE DETERMINISME GENETIQUE EST MONOGENIQUE. POUR LES ANILINOPYRIMIDINES, NOUS AVONS CARACTERISE UN PHENOTYPE DE RESISTANCE ELEVEE (ANIR1) ET 2 PHENOTYPES DE FAIBLE RESISTANCE (ANIR2 ET ANIR3) PRESENTANT UNE RESISTANCE SIMULTANEE A DES COMPOSES APPARTENANT A DES FAMILLES CHIMIQUES DIFFERENTES. AINSI ANIR2 EST RESISTANT AUX PHENYLPYRROLES TANDIS QU'ANIR3 EST RESISTANT AUX INHIBITEURS DE LA 14-DEMETHYLATION DES STEROLS (IDMS) ET AU FENHEXAMID. LE DETERMINISME GENETIQUE DE CHACUN DES PHENOTYPES ANIR EST MONOGENIQUE. POUR LES SOUCHES ANIR1, NOUS AVONS ECARTE LES HYPOTHESES D'UNE MUTATION PONCTUELLE DE LA CIBLE POTENTIELLE DES ANILINOPYRIMIDINES (LA CYSTATHIONINE -LYASE), D'UNE DETOXICATION ET D'UNE REDUCTION DE L'ACCUMULATION DE CES FONGICIDES. POUR LES SOUCHES ANIR2 ET ANIR3, LES CINETIQUES D'INCORPORATION D'UNE ANILINOPYRIMIDINE ET D'UN IDM ONT MONTRE UN INFLUX PASSIF ET UN EFFLUX ACTIF DE FONGICIDE. NOUS AVONS MIS EN EVIDENCE UNE REDUCTION DE L'ACCUMULATION DE CET IDM DANS LES SOUCHES ANIR3 ET TESTE L'HYPOTHESE D'UN MECANISME DU TYPE MDR EN ETUDIANT L'EXPRESSION DE 2 TRANSPORTEURS-ABC DANS LES SOUCHES SENSIBLE ET ANIR3 TRAITEES OU NON. DANS UN CAS, L'EXPRESSION EST CONSTITUTIVE ALORS QUE DANS L'AUTRE CAS, ELLE EST FORTEMENT INDUITE DANS LES SOUCHES TRAITEES.PARIS-BIUSJ-Thèses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

La micafungine (une nouvelle échinocandine)

PARIS-BIUP (751062107) / SudocSudocFranceF