Search results for "spore"
showing 10 items of 252 documents
Morphological and molecular redescription of the myxozoanUnicapsula pflugfelderiSchubert, Sprague & Reinboth 1975 from two teleost hosts in the M…
2009
Elongate plasmodia with myxosporean spores belonging to the genus Unicapsula, Davis, 1924 were found in the skeletal muscle of the striped seabream, Lithognathus mormyrus (L.), a candidate for the mediterranean aquaculture. The only species of Unicapsula described from the Mediterranean is Unicapsula pflugfelderi Schubert et al. 1975, which occurs in the picarel, Spicara smaris (L.). For morphological and molecular comparison of U. pflugfelderi from S. smaris with Unicapsula sp. from L. mormyrus measurements of plasmodia and spores, ultrastructural details and 18S and 28S rDNA sequences were analysed. Whereas plasmodia were 2-3 times larger in S. smaris than in L. mormyrus (length 2.47-0.81…
Playing with Time in Digital Fiction
2015
The exceptional quality of digital fictions lies in their inherently dynamic nature, how they may be flexibly programmed to generate new content and alter the already existing contents. This adds a new temporal level, compared to traditional fictions. Digital games, especially, incorporate aspects of simulation and narration in their structure. As interactive and dynamic media form, games are specifically temporal in nature. They offer us the flexibility and preciseness of digital simulations, with the potential of psychologically engaging narrative qualities, which together open up a whole new field of experimenting with temporally dynamic media. Much of the new media fictions partake in a…
Influence of Microspore Development on Pollen Protoplast Isolation in Digitalis obscura
1991
Summary Protocols for the enzymatic isolation of Digitalis obscura pollen protoplasts are described. The developmental stage of the microspores was a critical factor for successful isolation since protoplasts were obtained only from tetrads. The highest yield of viable protoplasts was achieved with an enzymatic mixture containing helicase, cellulase and pectolyase in 0.5 M sucrose. In different culture techniques employed, cell wall regeneration took place only when protoplasts were plated in agarose drops.
Micromorphological approach to the systematics of Mediterranean Isoëtes species (Isoëtaceae, Lycopodiophyta): analysis of the megaspore surface
2012
Megaspore ornamentation is one of the few morphological characters used in the taxonomy of the genus Isoëtes. In the present work, we test the application of this character for distinguishing some Isoëtes species occurring in the Mediterranean: Isoëtes sicula, which according to some authors should be included as a variety in I. histrix, and the recently described I. todaroana, whose affinity with other taxa is currently unknown. Two additional species (I. duriei, I. velata) were also included in the analysis. The megaspores were studied using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and chemical treatment. In all species, the megaspore surface is cove…
Empirical model building based on Weibull distribution to describe the joint effect of pH and temperature on the thermal resistance of Bacillus cereu…
2002
Abstract A mathematical model based on Weibull parameters was built to describe the joint effect of temperature and pH on thermal inactivation of Bacillus cereus spores (strain INRA TZ415). The effect of these factors on Weibull model parameters ( β , 1/ α ) was also studied. Heat inactivation tests were carried out in acidified carrot broth as vegetable substrate, following a full factorial design at four levels for temperature (80, 85, 90 and 95 °C) and pH (6.2, 5.8, 5.2 and 4.7). The Weibull distribution model provided good individual fits for the different combinations of temperature–pH tested, with discrepancy factors, D f , coming close to 25% for most cases. The temperature and pH di…
Inactivation of conidia of Penicillium chrysogenum, P. digitatum and P. italicum by ethanol solutions and vapours
2008
A fractional factorial design, 2(5-1) experiments, was used for assessing the influence of 5 factors: water activity, aw [0.7, 0.9], temperature, T ( degrees C) [10, 30], mode of application, A [liquid, vapour], ethanol concentration, E (% w/w) [5, 10] and time, t (d) [1, 4] on the inactivation of spores of Penicillium chrysogenum, P. digitatum and P. italicum. Survival was determined by germination at optimal conditions within 3d. The experimental response was log (N 0/Nt), where N 0 and Nt (spore ml(-1)) the concentrations of viable spores at t=0 and t respectively. By a decreasing order of sensitivity to ethanol, moulds were ranked as followed: P. digitatum, P. italicum and P. chrysogenu…
Modeling the effect of ethanol vapor on the germination time of Penicillium chrysogenum.
2005
The influence of ethanol vapor on germination of Penicillium chrysogenum was determined on yeast nitrogen base plus glucose agar medium at 25 degrees C. Ethanol vapors were generated by 0 to 6% (wt/wt) ethanol solutions at the bottom of hermetically closed petri dishes. The logistic equation was used to describe the data as the percentage of germination versus time and to estimate the germination time. The effect of ethanol concentration on germination time was described by a new reparameterized equation, resulting in an estimated limiting ethanol concentration of 4.3%. Up to 3% ethanol, all spores germinated, and the germination time increased with increasing ethanol concentration. At 3.5 …
Lifestyle dependent occurrence of airborne fungi
2018
Abstract. Fungi play important roles in the environment, agriculture, and human health. Most fungal species spread by wind-driven dispersal of spores, determining their occurrence and distribution in different environments. The dynamics of airborne fungi and their dependence on lifestyle and environmental conditions, however, are not well characterized. Here, we categorize the fungi detected in coarse and fine aerosol samples from continental boundary layer air using a lifestyle classification scheme that differentiates whether the fungi are (A) primarily associated to herbaceous or woody plants and (B), whether they are saprophytic, plant pathogenic, or surface inhabitants. Herbaceous fung…
Pythium stipitatumsp. nov. isolated from soil and plant debris taken in France, Tunisia, Turkey, and India
2009
Pythium stipitatum is a slow-growing oomycete and has been isolated from soil samples and plant materials from France, Tunisia, Turkey and India. Its morphological characteristics are reminiscent of those of Pythium ramificatum, discovered in Algeria by the corresponding author. Unfortunately, the Algerian isolate was not deposited in any culture collection and ultimately got lost. Those were the days when molecular description of fungi was not a fashion; hence, no molecular characteristics of the Algerian isolates were deposited to the GenBank. Moreover, its coralloid antheridial branches made it an easy prey to be considered as synonymous to Pythium minus. Because there are no living stra…
Use of the Weibull model to describe inactivation of dry harvested conidia of different Penicillium species by ethanol vapours
2010
Aims: This study aimed at modelling the effect of ethanol vapours, in the range 0·7–7·5 kPa, on the inactivation of dry-harvested conidia of Penicillium chrysogenum, Penicillium digitatum and Penicillium italicum. Methods and Results: Survival curves were modelled by a Weibull model: log (N/N0) = −1/2·303 (t/α)β. The shape parameter β was different from one in all cases, indicating that the classical first-order kinetics approach is the exception rather than the rule. Survival curves exhibited upward concavity (β < 1) with the notable exception of P. chrysogenum at ethanol vapour pressures 0·7 and 1·5 kPa. The scale parameter α (h) varied greatly depending on the ethanol vapour pressure a…