Search results for "spore"
showing 10 items of 252 documents
Inoculation of airborne conidia of Penicillium chrysogenum on the surface of a solid medium
2016
International audience; To reproduce a fungal contamination of food products by airborne conidia, a method to inoculate a few number (in the range 1-9) of conidia on the surface of agar media was developed. This technique would allow to determine accurately the time to detection of fungal colonies, then the mould free shelf-life of food products by using dry conidia. The method was based on dry-harvesting the conidia in the lid by gently taping the bottom of the dishes where sporulating mycelium was grown, retaining the conidia on glass beads, and, aseptically transferring the beads to successive Petri dishes to "dilute" the samples. Among the eleven factors tested by means of an experiment…
Modelling the effect of temperature, pH, water activity, and organic acids on the germination time of Penicillium camemberti and Penicillium roquefor…
2017
International audience; In this study, the influence of environmental factors on the germination time of Penicillium camemberti and Penicillium roqueforti conidia was evaluated. To do so, the effects of i/temperature, pH, water activity, and ii/organic acids were determined using models based on i/cardinal values, and ii/minimum inhibitory concentration (MIC) respectively. Cardinal values for germination of conidia were not observed to be species dependent. Minimum temperatures were estimated to be below the freezing point, with an optimum of 26.9 degrees C, and a maximum of 33.5 degrees C. For both species, minimal and optimal a(w) values were found to be 0.83 and 0.99, respectively, while…
Nanoparticle decoration impacts airborne fungal pathobiology
2018
Airborne fungal pathogens, predominantly Aspergillus fumigatus, can cause severe respiratory tract diseases. Here we show that in environments, fungal spores can already be decorated with nanoparticles. Using representative controlled nanoparticle models, we demonstrate that various nanoparticles, but not microparticles, rapidly and stably associate with spores, without specific functionalization. Nanoparticle-spore complex formation was enhanced by small nanoparticle size rather than by material, charge, or "stealth" modifications and was concentration-dependently reduced by the formation of environmental or physiological biomolecule coronas. Assembly of nanoparticle-spore surface hybrid s…
Characterization of Bacillus thuringiensis isolates by their insecticidal activity and their production of Cry and Vip3 proteins.
2018
WOS: 000449027600099 PubMed ID: 30383811 Bacillus thuringiensis (Bt) constitutes the active ingredient of many successful bioinsecticides used in agriculture. In the present study, the genetic diversity and toxicity of Bt isolates was investigated by characterization of native isolates originating from soil, fig leaves and fruits from a Turkish collection. Among a total of 80 Bt isolates, 18 of them were found carrying a vip3 gene (in 23% of total), which were further selected. Insecticidal activity of spore/crystal mixtures and their supernatants showed that some of the Bt isolates had significantly more toxicity against some lepidopteran species than the HD1 reference strain. Five isolate…
A giant type I polyketide synthase participates in zygospore maturation in Chlamydomonas reinhardtii
2017
Polyketide synthases (PKSs) occur in many bacteria, fungi and plants. They are highly versatile enzymes involved in the biosynthesis of a large variety of compounds including antimicrobial agents, polymers associated with bacterial cell walls and plant pigments. While harmful algae are known to produce polyketide toxins, sequences of the genomes of non-toxic algae, including those of many green algal species, have surprisingly revealed the presence of genes encoding type I PKSs. The genome of the model alga Chlamydomonas reinhardtii (Chlorophyta) contains a single type I PKS gene, designated PKS1 (Cre10.g449750), which encodes a giant PKS with a predicted mass of 2.3 MDa. Here, we show that…
Native arbuscular mycorrhizal symbiosis alters foliar bacterial community composition.
2017
The effects of arbuscular mycorrhizal (AM) fungi on plant-associated microbes are poorly known. We tested the hypothesis that colonization by an AM fungus affects microbial species richness and microbial community composition of host plant tissues. We grew the grass, Deschampsia flexuosa in a greenhouse with or without the native AM fungus, Claroideoglomus etunicatum. We divided clonally produced tillers into two parts: one inoculated with AM fungus spores and one without AM fungus inoculation (non-mycorrhizal, NM). We characterized bacterial (16S rRNA gene) and fungal communities (internal transcribed spacer region) in surface-sterilized leaf and root plant compartments. AM fungus inoculat…
Analysis of the Transcriptome of the Red Seaweed Grateloupia imbricata with Emphasis on Reproductive Potential
2018
Grateloupia imbricata is an intertidal marine seaweed and candidate model organism for both industry and academic research, owing to its ability to produce raw materials such as carrageenan. Here we report on the transcriptome of G. imbricata with the aim of providing new insights into the metabolic pathways and other functional pathways related to the reproduction of Grateloupia species. Next-generation sequencing was carried out with subsequent de novo assembly and annotation using state-of-the-art bioinformatic protocols. The results show the presence of transcripts required for the uptake of glycerol, which is a specific carbon source for in vitro culture of G. imbricata and nucleotide …
Influence of temperature, copper and CO2on spore counts and geosmin production byPenicillium expansum
2012
Background and Aim: Musts and wines produced from rotten grapes often have an earthy/musty odour, with geosmin the responsible compound. Penicillium expansum is considered a potential source of geosmin in rotten grapes from vineyards treated with copper-based fungicides. Methods and Results: The laboratory study assessed the influence of temperature (10‐30°C), copper concentration (0‐76.50 mg/L) and CO 2 in the headspace (0.03‐3%) on the spore count and the production of geosmin by P. expansum according to a Doehlert design. The spore count and the production of geosmin (ng/mg biomass) were significantly correlated (r = 0.78). Copper had no significant effect on the spore count but was the …
Soil fungi invest into asexual sporulation under resource scarcity, but trait spaces of individual isolates are unique
2022
During the last few decades, a plethora of sequencing studies provided insight into fungal community composition under various environmental conditions. Still, the mechanisms of species assembly and fungal spread in soil remain largely unknown. While mycelial growth patterns are studied extensively, the abundant formation of asexual spores is often overlooked, though representing a substantial part of the fungal life cycle relevant for survival and dispersal. Here, we explore asexual sporulation (spore abundance, size and shape) in 32 co-occurring soil fungal isolates under varying resource conditions, to answer the question whether resource limitation triggers or inhibits fungal investment…
Safety and immunomodulatory effects of three probiotic strains isolated from the feces of breast-fed infants in healthy adults: SETOPROB study.
2013
We previously described the isolation and characterization of three probiotic strains from the feces of exclusively breast-fed newborn infants: Lactobacillus paracasei CNCM I-4034, Bifidobacterium breve CNCM I-4035 and Lactobacillus rhamnosus CNCM I-4036. These strains were shown to adhere to intestinal mucus in vitro, to be sensitive to antibiotics and to resist biliary salts and low pH. In the present study, a multicenter, randomized, double-blind, placebo-controlled trial with 100 healthy volunteers in three Spanish cities was carried out to evaluate the tolerance, safety, gut colonization and immunomodulatory effects of these three probiotics. Volunteers underwent a 15-day washout perio…