Search results for "Spore"

A new Lichenostigma on vagrant Aspicilia species

2003

AbstractLichenostigma radicans Calat. & Barreno, a lichenicolous fungus growing on vagrant Aspicilia species, is described as new to science from Spain. It is superficially similar to L. maureri, with cushion-like ascomata, but differing mainly by its ascomata connected at their base to immersed, brown, vegetative hyphae. Comments on the variability of iodine reactions of asci and ascospore walls, and on an associated conidial fungus with small bacilliform conidia, are given for L. maureri.

Growth characteristics of Aspergillus chevalieri and other fungi from under-coating of chocolate truffles

1997

Growth characteristics of fungi, which occasionally affected chocolate truffles, have been studied, using moulded and non-moulded samples. A whitish mycelial growth, located at the filling-coating interface is identified as Eurotium/Aspergillus chevalieri. The spores of other xerophilic molds (Aspergillus fumigatus, A. penicilloides and Penicillium verrucosum) were also found at the filling-coating interface. The water activity of chocolate coating was low enough to prevent fungal growth on the external surface of the truffles. However, the water activity of the filling, due to presence of cream, is sufficient enough to allow the growth of xerophilic moulds. The data on growth characteristi…

Effect of storage conditions (relative humidity, duration, and temperature) on the germination time of Aspergillus carbonarius and Penicillium chryso…

2012

Fungal conidia are disseminated, often in the air, for a certain period of time, prior to contaminating food products. The objective of this study was to examine the effects of the relative humidity, RH (%), time (day), and temperature (°C) during this period of time, called "storage", on the germination time, τ (h), of Aspergillus carbonarius and Penicillium chrysogenum. A Doehlert design was used in the range, 20-100% RH, 2-28 days, and 5-25 °C. As compared to un-stored conidia, the germination time of conidia stored at 60% RH, 15 days, 5 °C was increased by 23 and 28%, for A. carbonarius and P. chrysogenum, respectively. Stored conidia exhibited a minimum τ value at 60% RH, and 100% RH f…

2013

Abstract. Bioaerosols are relevant for public health and may play an important role in the climate system, but their atmospheric abundance, properties, and sources are not well understood. Here we show that the concentration of airborne biological particles in a North American forest ecosystem increases significantly during rain and that bioparticles are closely correlated with atmospheric ice nuclei (IN). The greatest increase of bioparticles and IN occurred in the size range of 2–6 μm, which is characteristic for bacterial aggregates and fungal spores. By DNA analysis we found high diversities of airborne bacteria and fungi, including groups containing human and plant pathogens (mildew, s…

Morphological and molecular taxonomy ofPythium longisporangiumsp. nov. isolated from the Burgundian region of France

2005

During the course of an investigation on the Pythiaceous oomycetes occurring in the Burgundian vineyards, some species of Pythium possessing mainly hypogynous antheridia were found. These had been classified as oomycetes belonging to the ‘‘Pythium rostratum’’ group for a long time. Three of these isolates, having similar structures and growth, are very closely related to a recently described species, Pythium bifurcatum Paul. A close look at these, however, underlines some fundamental differences with the latter. Not all of them produce zoospores but have very large sporangia. The type specimen is F-1200 (B 76a) which is a medium-slow growing saprophyte. The sequence of the ITS region of the…

Pythium segnitiumsp. nov., isolated from the Canary Islands – its taxonomy, ITS region of rDNA, and comparison with related species

2002

Pythium segnitium (CI-44) was isolated from some soil samples taken in the Canary Islands (Spain). This new species is a slow-growing fungus and is perfectly adapted to terrestrial habitat. It belongs to the group of Pythium that have smooth-walled oogonia, mostly hypogynous antheridia, and plerotic oospores. The fungus lacks sporangia, zoospores, and hyphal bodies are rarely formed. Thus the asexual reproduction, which is so common for fungi and especially for the aquatic ones, is completely lacking in this case. However the fungus reproduces sexually by the formation of oogonia, antheridia and oospores plentifully. The taxonomic description of this fungus, the nucleotide sequence of the i…

Assessing the effectiveness of Byssochlamys nivea and Scopulariopsis brumptii in pentachlorophenol removal and biological control of two Phytophthora…

2016

Bioremediation and biological-control by fungi have made tremendous strides in numerous biotechnology applications. The aim of this study was to test Byssochlamys nivea and Scopulariopsis brumptii in sensitivity and degradation to pentachlorophenol (PCP) and in biological-control of Phytophthora cinnamomi and Phytophthora cambivora. B. nivea and S. brumptii were tested in PCP sensitivity and degradation in microbiological media while the experiments of biological-control were carried out in microbiological media and soil. The fungal strains showed low PCP sensitivity at 12.5 and 25 mg PCP L(-1) although the hyphal size, fungal mat, patulin, and spore production decreased with increasing PCP…

Development of a rapid and highly sensitive biochemical method for the measurement of fungal spore viability. An alternative to the CFU method

2001

Abstract 1 A biochemical method, based on dehydrogenase activity (DHA) measurement, has been developed as an alternative to colony forming unit (CFU) enumeration, for assessing the viability of fungal spores. In viable cells, a tetrazolium salt (MTT) is reduced to a coloured formazan (MTTf) by cellular dehydrogenase enzymes. From the colorimetric assay developed by Mosmann for mammalian cells, the procedure has been adapted and optimised using P. digitatum spores as a model. Propan-2-ol has been selected as the best solvent to extract the MTTf from the spores. The sensitivity of the method has been considerably increased by determining the optimal conditions of incubation for the MTT reduct…

Direct investigation of viscosity of an atypical inner membrane of Bacillus spores: A molecular rotor/FLIM study

2013

Abstract We utilize the fluorescent molecular rotor Bodipy-C12 to investigate the viscoelastic properties of hydrophobic layers of bacterial spores Bacillus subtilis. The molecular rotor shows a marked increase in fluorescence lifetime, from 0.3 to 4 ns, upon viscosity increase from 1 to 1500 cP and can be incorporated into the hydrophobic layers within the spores from dormant state through to germination. We use fluorescence lifetime imaging microscopy to visualize the viscosity inside different compartments of the bacterial spore in order to investigate the inner membrane and relate its compaction to the extreme resistance observed during exposure of spores to toxic chemicals. We demonstr…

Acute Toxicity Tests with Cadmium, Lead, Sodium Dodecyl Sulfate, and Bacillus thuringiensis on a Temporary Pond Ostracod

2012

A complete assessment of effects of pollutants in the environment requires the use of a wide assemblage of test organisms. Crustaceans have been widely used in aquatic environments, but within this group, ostracods have been overlooked, even though they are one of the commonest groups of animals in temporary waters. Within this framework, static acute toxicity bioassays were conducted with heavy metals Cd and Pb, the surfactant SDS and spores of the bacteria Bacillus thuringiensis var. israeliensis using adult parthenogenetic females of the temporary pond ostracod Heterocypris bosniaca. Experiments were run at 20 °C and in a 12 by 12 h photoperiod. The toxicity tests results are expressed a…