Search results for "Hypha"
showing 10 items of 85 documents
Impaired immune response to Candida albicans in aged mice
2006
The prevalence of opportunistic fungal infections has increased dramatically among the aged population in recent years. This work investigated the effect of ageing on murine defences against Candida albicans. Aged C57BL/6 mice that were experimentally infected intravenously had a significantly impaired survival and a higher tissue fungal burden compared with young mice. In vitro production of tumour necrosis factor (TNF)-α by macrophages from aged mice in response to yeast cells and hyphae of C. albicans was significantly lower than production by macrophages from young mice. In vitro production of cytokines, such as TNF-α and gamma interferon (IFN-γ), by antigen-stimulated splenocytes from …
A new Phytophthora sp causing a basal canker on beech in Italy.
2003
In autumn 2001, bleeding cankers were observed on the basal portion of the trunk of a declining tree in a forest stand of European beech (Fagus sylvatica L.) in Latium (central Italy). A Phytophthora sp. was isolated consistently from infected trunk bark using whole apples as bait. Isolations were made from brown lesions that developed in the apple pulp around the inserted bark pieces. Pure cultures were obtained by using hyphal tip transfers. Colonies were stellate on V8 juice agar (V8A), uniform to slightly radiate on cornmeal agar, and cottony, without a distinct growth pattern on potato dextrose agar (PDA). On V8A, radial growth rates were 2.1, 4.8, and 4.5 mm/day at 10, 15, and 20°C, …
Cytology of Thamnidium elegans Link. II. Distribution and behaviour of nuclei in hyphae, sporangiophores and sporangiospores.
1976
The resting nuclei in hyphae, sporangiophores and sporangiospores of sporangia and sporangiola of Thamnidium elegans consist of a large centrals nucleolus and a shell of chromatin surrounding the nucleolus. Division of the nucleus in hyphae and sporangiospores is achieved by elongation and constriction.
EngineeredControl of Cell Morphology In Vivo Reveals Distinct Roles for Yeast andFilamentous Forms of Candida albicans duringInfection
2003
ABSTRACT It is widely assumed that the ability of Candida albicans to switch between different morphologies is required for pathogenesis. However, most virulence studies have used mutants that are permanently locked into either the yeast or filamentous forms which are avirulent but unsuitable for discerning the role of morphogenetic conversions at the various stages of the infectious process. We have constructed a strain in which this developmental transition can be externally modulated both in vitro and in vivo. This was achieved by placing one copy of the NRG1 gene (a negative regulator of filamentation) under the control of a tetracycline-regulatable promoter. This modified strain was th…
Dimethylsulfoxide as carrier in enzyme cytochemistry.
1971
Addition of dimethylsulfoxide (DMSO) to the incubation medium of succinate dehydrogenase in a concentration of 10% enhances the staining reaction in the hyphae of the fungus Cercosporella herpotrichoides after an incubation period of 15 min. Controls without DMSO remain unstained. DMSO causes a rapid penetration of the components of the medium through the mucilage that covers the hyphae.
Toll-like receptor-2 is essential in murine defenses against Candida albicans infections
2004
In this work, we studied the role of toll-like receptor-2 (TLR2) in murine defenses against Candida albicans. TLR2-deficient mice experimentally infected intraperitoneally (i.p.) or intravenously (i.v.) in vivo had very significant impaired survival compared with that of control mice. In vitro production of TNF-alpha and macrophage inhibitory protein-2 (MIP-2) by macrophages from TLR2-/- mice in response to yeasts and hyphae of C. albicans were significantly lower (80% and 40%, respectively; P <0.05) than production by macrophages from wild-type mice. This impaired production of TNF-alpha and MIP-2 probably contributed to the 41% decreased recruitment of neutrophils to the peritoneal cavity…
Identification of the mstE Gene Encoding a Glucose-inducible, Low Affinity Glucose Transporter in Aspergillus nidulans
2006
The mstE gene encoding a low affinity glucose transporter active during the germination of Aspergillus nidulans conidia on glucose medium has been identified. mstE expression also occurs in hyphae, is induced in the presence of other repressing carbon sources besides glucose, and is dependent on the function of the transcriptional repressor CreA. The expression of MstE and its subcellular distribution have been studied using a MstE-sGFP fusion protein. Concordant with data on mstE expression, MstE-sGFP is synthesized in the presence of repressing carbon sources, and fluorescence at the periphery of conidia and hyphae is consistent with MstE location in the plasma membrane. Deletion of mstE …
Microscopical and Mycological Investigations on Wood of Pendunculate Oak (Quercus robur L) Relative to the Occurrence of Oak Decline
1996
Summary Microscopical studies exhibited great differences between healthy and damaged pendunculate oak trees (Quercus robur L.) relative to the state of sapwood vessels and the degree of fungal infection. In the sapwood of damaged trees deposits, discolorations and early tylosis formations were found which frequently occurred in combination with fungal infections. These results lead to the assumption that the defence reaction of the trees probably induced by fungal infection changes the structure of the tree vessels to such an extent that their water transfer function is disturbed. Some fungal genera playing an important role in the discussion of the causes of oak decline could be isolated.…
Impairment of leaf hydraulics in young plants of Citrus aurantium (sour orange) infected by Phoma tracheiphila.
2007
Phoma trachephila (Petri) Kantschaveli et Gikachvili causes dieback of several Citrus species. The impact of this fungus on leaf hydraulics was studied in Citrus aurantium L. (sour orange) with the aim of identifying the primary mechanism of damage to leaves. Leaves inoculated with a conidial suspension were measured for conductance to water vapor (gL) and specific hydraulic conductance (Kleaf) every 3 days after inoculation. The earliest symptom of infection consisted of vein chlorosis. Functional vein density (FVD) was monitored and microscopic observations were made of major vein conduits. Impairment of vein hydraulics started 25 days after inoculation with a losses of Kleaf of 40% and g…
Isolation and characterization of anavirulent Candida albicansyeast monomorphic mutant
2003
Mutagenesis of Candida albicans strain ATCC 26555 with N-methyl-nitro-N-nitrosoguanidine followed by plating on solid yeast nitrogen base-N-acetylglucosamine medium at 37 degrees C yielded colony morphology variants that were characterized as forming smooth colonies, in contrast to the rough colonies formed by the parental strain. One yeast monomorphic mutant, CAL4, was studied in detail. Strain CAL4 is defective in filamentous growth, unable to form hyphae or pseudohyphae in vivo and in vitro. These filamentous structures are not elicited by commonly used external stimuli such as serum. The mutant had no obvious alterations in its mannan, glucan or chitin content. The total quantity of non…