376 research outputs found
Pseudallescheria and Scedosporium: Emerging Oopportunists
International audienc
Communication of the ECMM-ISHAM Working Group on Pseudallescheria/Scedosporium Infections. Update on Scedosporium/Pseudallescheria Infections
Date du colloque : 04/2008</p
Fusarium:Molecular Diversity and Intrinsic Drug Resistance
Contains fulltext :
172596.PDF (publisher's version ) (Open Access
Environmental isolation of black yeast-like fungi involved in human infection
The present study focuses on potential agents of chromoblastomycosis and
other endemic diseases in the state of Paraná, Southern Brazil. Using a
highly selective protocol for chaetothyrialean black yeasts and relatives,
environmental samples from the living area of symptomatic patients were
analysed. Additional strains were isolated from creosote-treated wood and
hydrocarbon-polluted environments, as such polluted sites have been supposed
to enhance black yeast prevalence. Isolates showed morphologies compatible
with the traditional etiological agents of chromoblastomycosis, e.g.
Fonsecaea pedrosoi and Phialophora verrucosa, and of agents of
subcutaneous or systemic infections like Cladophialophora bantiana
and Exophiala jeanselmei. Some agents of mild disease were indeed
encountered. However, molecular analysis proved that most environmental
strains differed from known etiologic agents of pronounced disease syndromes:
they belonged to the same order, but mostly were undescribed species. Agents
of chromoblastomycosis and systemic disease thus far are prevalent on the
human host. The hydrocarbon-polluted environments yielded yet another spectrum
of chaetothyrialean fungi. These observations are of great relevance because
they allow us to distinguish between categories of opportunists, indicating
possible differences in pathogenicity and virulence
Chaos Synchronization and Spontaneous Symmetry Breaking in Symmetrically Delay Coupled Semiconductor Lasers
PACS: 05.45.Xt, 42.55.Px, 42.65.SfWe present experimental and numerical investigations of the dynamics of two device-identical, optically coupled semiconductor lasers exhibiting a delay in the coupling. Our results give evidence for subnanosecond coupling-induced synchronized chaotic dynamics in conjunction with a spontaneous symmetry-breaking: we find a well-defined time lag between the dynamics of the two lasers, and an asymmetric physical role of the subsystems. We demonstrate that the leading laser synchronizes its lagging counterpart, whereas the synchronized lagging laser drives the coupling-induced instabilities.Peer reviewe
The neurotropic black yeast Exophiala dermatitidis has a possible origin in the tropical rain forest
The black yeast Exophiala dermatitidis is known as a rare
etiologic agent of neurotropic infections in humans, occurring particularly in
East and Southeast Asia. In search of its natural habitat, a large sampling
was undertaken in temperate as well as in tropical climates. Sampling sites
were selected on the basis of the origins of previously isolated strains, and
on the basis of physiological properties of the species, which also determined
a selective isolation protocol. The species was absent from outdoor
environments in the temperate climate, but present at low abundance in
comparable habitats in the tropics. Positive outdoor sites particularly
included faeces of frugivorous birds and bats, in urban as well as in natural
areas. Tropical fruits were found E. dermatitidis positive at low
incidence. Of the human-made environments sampled, railway ties contaminated
by human faeces and oily debris in the tropics were massively positive, while
the known abundance of the fungus in steam baths was confirmed. On the basis
of the species' oligotrophy, thermotolerance, acidotolerance, moderate
osmotolerance, melanization and capsular yeast cells a natural life cycle in
association with frugivorous animals in foci in the tropical rain forest,
involving passage of living cells through the intestinal tract was
hypothesized. The human-dominated environment may have become contaminated by
ingestion of wild berries carrying fungal propagule
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