New papers on Damp-building related illness, trichothecene toxins, antigen to stachybotrys discovered

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Toxicol Sci. 2007 Nov 15 [Epub ahead of print]

Stachybotrys chartarum, Trichothecene Mycotoxins, and Damp

Building-Related Illness: New Insights into a Public Health Enigma.

Pestka JJ, Yike I, Dearborn DG, Ward MD, Harkema JR.

Center for Integrative Toxicology.

Damp building-related illnesses (DRBI) include a myriad of

respiratory, immunologic and neurologic symptoms that are sometimes

etiologically linked to aberrant indoor growth of the toxic black

mold, Stachybotrys chartarum. Although supportive evidence for such

linkages are limited, there are exciting new findings about this

enigmatic organism relative to its environmental dissemination, novel

bioactive components, unique cellular targets and molecular mechanisms

of action which provide insight into the S. chartarum's potential to

evoke allergic sensitization, inflammation and cytotoxicity in the

upper and lower respiratory tracts. Macrocyclic trichothecene

mycotoxins, produced by one chemotype of this fungus, are potent

translational inhibitors and stress kinase activators that appear to

be a critical underlying cause for a number of adverse effects.

Notably, these toxins form covalent protein adducts in vitro and in

vivo and, furthermore, cause neurotoxicity and inflammation in the

nose and brain of the mouse. A second S.chartarum chemotype has

recently been shown to produce atranones - mycotoxins that can induce

pulmonary inflammation. Other biologically active products of this

fungus that might contribute to pathophysiologic effects include

proteinases, hemolysins, beta-glucan and spirocyclic drimanes. Solving

the enigma of whether Stachybotrys inhalation indeed contributes to

DRBI will require studies of the pathophysiologic effects of low dose

chronic exposure to well-characterized, standardized preparations of

S. chartarum spores and mycelial fragments, and, co-exposures with

other environmental cofactors. Such studies must be linked to improved

assessments of human exposure to this fungus and its bioactive

constituents in indoor air using both state-of-the-art

sampling/analytical methods and relevant biomarkers.

PMID: 18007011 [PubMed - as supplied by publisher]

4: Appl Microbiol Biotechnol. 2007 Nov;77(2):293-300. Epub 2007 Oct

16.Click here to read

Mycopathologia. 2007 Nov 29 [Epub ahead of print]

Immunohistochemical and immunocytochemical detection of SchS34

antigen in Stachybotrys chartarum spores and spore impacted mouse

lungs.

Rand TG, JD.

Department of Biology, Saint 's University, Halifax, NS,

Canada, B3H 3C3, thomas.rand@....

The purpose of this study was to evaluate the distribution of a 34

kD antigen isolated from S. chartarum sensu lato in spores and in the

mouse lung 48 h after intra-tracheal instillation of spores by

immuno-histochemistry. This antigen was localized in spore walls,

primarily in the outer and inner wall layers and on the external wall

surfaces with modest labelling observed in cytoplasm.

Immuno-histochemistry revealed that in spore impacted mouse lung,

antigen was again observed in spore walls, along the outside surface

of the outer wall and in the intercellular space surrounding spores.

In lung granulomas the labelled antigen formed a diffusate, some 2-3x

the size of the long axis of spores, with highest concentrations

nearest to spores. Collectively, these observations indicated that

this protein not only displayed a high degree of specificity with

respect to its location in spores and wall fragments, but also that it

slowly diffuses into surrounding lungs.

PMID: 18046622 [PubMed - as supplied by publisher]

Appl Microbiol Biotechnol. 2007 Nov;77(2):293-300. Epub 2007 Oct 16.

Purification and biochemical characterization of a

transglucosilating beta-glucosidase of Stachybotrys strain.

Saibi W, Amouri B, Gargouri A.

Laboratoire de Génétique Moléculaire des Eucaryotes, Centre de

biotechnologie de Sfax, CBS, route Sidi Mansour, Sfax, 3061, Tunisia,

faouzi.gargouri@....

The filamentous fungus Stachybotrys sp has been shown to possess a

rich beta-glucosidase system composed of five beta-glucosidases. One

of them was already purified to homogeneity and characterized. In this

work, a second beta-glucosidase was purified and characterized. The

filamentous fungal A19 strain was fed-batch cultivated on cellulose,

and its extracellular cellulases (mainly beta-glucosidases) were

analyzed. The purified enzyme is a monomeric protein of 78 kDa

molecular weight and exhibits optimal activity at pH 6.0 and at 50

degrees C. The kinetic parameters, K (m) and V (max), on

para-nitro-phenyl-beta-D: -glucopyranosid (p-NPG) as a substrate were,

respectively, 1.846 +/- 0.11 mM and 211 +/- 0.08 mumol min(-1) ml(-1).

One interesting feature of this enzyme is its high stability in a wide

range of pH from 4 to 10. Besides its aryl beta-glucosidase activity

towards salicin, methylumbellypheryl-beta-D: -glucoside (MU-Glc), and

p-NPG, it showed a true beta-glucosidase activity because it splits

cellobiose into two glucose monomers. This enzyme has the capacity to

synthesize short oligosaccharides from cellobiose as the substrate

concentration reaches 30% with a recovery of 40%. We give evidences

for the involvement of a transglucosylation to synthesize

cellotetraose by a sequential addition of glucose to cellotriose.

PMID: 17938914 [PubMed - in process]