New insights in dermatophyte research

Dermatophyte research has renewed interest because of changing human floras with changing socioeconomic conditions, and because of severe chronic infections in patients with congenital immune disorders. Main taxonomic traits at the generic level have changed considerably, and now fine-tuning at the species level with state-of-the-art technology has become urgent. Research on virulence factors focuses on secreted proteases now has support in genome data. It is speculated that most protease families are used for degrading hard keratin during nitrogen recycling in the environment, while others, such as Sub6 may have emerged as a result of ancestral gene duplication, and are likely to have specific roles during infection. Virulence may differ between mating partners of the same species and concepts of zoo- and anthropophily may require revision in some recently redefined species. Many of these questions benefit from international cooperation and exchange of materials. The aim of the ISHAM Working Group Dermatophytes aims to stimulate and coordinate international networking on these fungi

Toward a Novel Multilocus Phylogenetic Taxonomy for the Dermatophytes.

Type and reference strains of members of the onygenalean family Arthrodermataceae have been sequenced for rDNA ITS and partial LSU, the ribosomal 60S protein, and fragments of β-tubulin and translation elongation factor 3. The resulting phylogenetic trees showed a large degree of correspondence, and topologies matched those of earlier published phylogenies demonstrating that the phylogenetic representation of dermatophytes and dermatophyte-like fungi has reached an acceptable level of stability. All trees showed Trichophyton to be polyphyletic. In the present paper, Trichophyton is restricted to mainly the derived clade, resulting in classification of nearly all anthropophilic dermatophytes in Trichophyton and Epidermophyton, along with some zoophilic species that regularly infect humans. Microsporum is restricted to some species around M. canis, while the geophilic species and zoophilic species that are more remote from the human sphere are divided over Arthroderma, Lophophyton and Nannizzia. A new genus Guarromyces is proposed for Keratinomyces ceretanicus. Thirteen new combinations are proposed; in an overview of all described species it is noted that the largest number of novelties was introduced during the decades 1920-1940, when morphological characters were used in addition to clinical features. Species are neo- or epi-typified where necessary, which was the case in Arthroderma curreyi, Epidermophyton floccosum, Lophophyton gallinae, Trichophyton equinum, T. mentagrophytes, T. quinckeanum, T. schoenleinii, T. soudanense, and T. verrucosum. In the newly proposed taxonomy, Trichophyton contains 16 species, Epidermophyton one species, Nannizzia 9 species, Microsporum 3 species, Lophophyton 1 species, Arthroderma 21 species and Ctenomyces 1 species, but more detailed studies remain needed to establish species borderlines. Each species now has a single valid name. Two new genera are introduced: Guarromyces and Paraphyton. The number of genera has increased, but species that are relevant to routine diagnostics now belong to smaller groups, which enhances their identification

Ligands, their receptors and ... plasma membranes.

Ligand-receptor interactions are customarily described by equations that apply to solutes. Yet, most receptors are present in cell membranes so that sufficiently lipophilic ligands could reach the receptor by a two-dimensional approach within the membrane. As summarized in this review, this may affect the ligand-receptor interaction in many ways. Biophysicians calculated that, compared to a three-dimensional approach from the liquid phase, such approach could alter the time the ligands need to find a receptor. Biochemists found that ligand incorporation in lipid bilayers modifies their conformation. This, along with the depth at which the ligands reside in the bilayer, will affect the probability of successful receptor interaction. Novel mechanisms were also introduced, including “exosite” binding and ligand translocation between the receptor&#8217;s alpha-helical transmembrane domains. Pharmacologists focused attention at ligand concentrations in membrane, their adsorption and release rates and the effects thereof on ligand potency and residence time at the&nbsp;receptor.</p

Non-competitive interaction between raclopride and spiperone on human D-receptors in intact Chinese hamster ovary cells.

We recently investigated the binding properties of the antagonists [(3)H]-raclopride and [(3)H]-spiperone to intact Chinese hamster ovary cells expressing recombinant human D(2long)-dopamine receptors (CHO-D(2L) cells). Compared with saturation binding with [(3)H]-raclopride, raclopride reduced [(3)H]-spiperone binding with to low potency in competition binding experiments. The present findings illustrate the ability of spiperone to inhibit [(3)H]-raclopride binding non-competitively. While raclopride only decreases the apparent K(D) of [(3)H]-raclopride in saturation binding experiments, spiperone only decreases the number of sites to which [(3)H]-raclopride binds with high affinity. Also, while the IC(50) of raclopride depends on the concentration of [(3)H]-raclopride in competition experiments, this is not the case for spiperone. Kinetic studies reveal that the binding of raclopride at its high affinity sites does not affect the association of subsequently added [(3)H]-spiperone nor the rebinding of freshly dissociated [(3)H]-spiperone to the same or surrounding receptors. Yet, spiperone does not affect the dissociation rate of [(3)H]-raclopride and raclopride does not affect the (genuine) dissociation rate of [(3)H]-spiperone. The easiest way to interpret the present findings in molecular terms is to assume that D(2L)-receptors or their dimeric complexes possess two distinct binding sites: one with high affinity/accessibility for [(3)H]-raclopride and the other one with high affinity/accessibility for [(3)H]-spiperone. The ability of bound spiperone to inhibit high affinity raclopride binding while the reverse is not the case suggests for the occurrence of non-reciprocal allosteric interactions. These new findings could point at the occurrence of allosteric interactions between different classes of D(2)-receptor&nbsp;antagonists.</p

The role of indoor pollution in the development and maintenance of chronic airway inflammation in children.

&lt;p&gt;Air pollution is one of the great problems of this century and it plays an important role in the increasing prevalence of chronic inflammatory problems in the upper airway in children. Since their lungs and immune system are not fully developed when exposure begins, newborns and children appear to be more sensitive to the effects of both outdoor and indoor air pollution. Furthermore, children spend most of their time indoors and are exposed more often to pollutants in indoor air. The link between health problems, chemical products and allergens (the latter mainly from cats and mites) has been extensively studied. Other important indoor contaminants are fungi, which are often present in damp buildings and can cause severe respiratory disease by producing spores, allergens, volatile irritant compounds and toxins. A proper identification of mould contamination of this kind is vital for correct diagnosis, treatment and the prevention of health problems, and improvements have been observed after the removal or cleaning of the contaminated materials and improvements to the ventilation of buildings. While a possible association between respiratory symptoms, such as rhinitis, and the presence of fungi in the indoor environment has been documented by several authors, other studies have observed no significant relationship. The development of standardised sampling, detection and diagnostic tests will be essential to understand the proper role of fungi in the indoor atmosphere and their impact on public health.&lt;/p&gt;</p

Determination of the sterol compound ergosterol by UPLC-APCI-MS/MS

presentation at Waters 2013 MS Technology Days</p

Een uitbraak van tinea capitis in een lagere school in de provincie Antwerpen, een uitdaging voor preventive en behandeling

&lt;p&gt;Tinea capitis is een schimmelinfectie van de hoofdhuid die vooral voorkomt bij kinderen en die een orale antimycotische behandeling vereist. In mei 2013 meldde een arts van het Centrum voor Leerlingenbegeleiding verschillende gevallen van tinea capitis bij scholieren van een lagere school aan de dienst Infectieziektebestrijding Antwerpen. We screenden alle leerlingen en verwezen verdachte gevallen door naar een arts met de aanbeveling een orale behandeling te starten indien tinea capitis werd gediagnosticeerd. Stalen werden drie weken later verzameld en getest in een gespecialiseerd laboratorium. We voerden een retrospectieve cohortestudie uit. We definieerden een vermoedelijk geval als een leerling van de school waarbij de schoolarts een tinea capitis-infectie vermoedde en waarbij de huis- of huidarts na doorverwijzing de klinische symptomen van tinea capitis herkende. Van de 291 leerlingen, waren er 19 (6,5%) vermoedelijke gevallen. Van deze 19 leerlingen kregen er 14 (73%) een orale behandeling voorgeschreven. Een besmette broer of zus of een besmet klasgenootje verhoogden het risico op besmetting. De verantwoordelijke schimmel was Microsporum audouinii. Verder onderzoek toonde aan dat er in plaatselijke laboratoria iets misgelopen was met de typering van de schimmels. We raadden aan om behandelingsrichtlijnen op te stellen, om dergelijke uitbraken extra aandacht te geven, intrafamiliale transmissie te kunnen voorkomen en ook om laboratoria met ervaring in mycologie in te schakelen.&lt;/p&gt;</p