The Pathogenicity of Stachybotrys chartarum.

Stachybotrys chartarum is a dematiaceous fungus that is ubiquitous in our living environment. This fungus has long been regarded as non-pathogenic and its inhalation effect on humans has been scarcely studied. Recently, however, epidemiologic studies on acute idiopathic pulmonary hemorrhage in infants suggested that the fungus might be potentially pathogenic to humans. To determine the pathogenicity of this fungus, its interaction with the host defense system was studied using polymorphonuclear leukocytes (PMNs) and macrophages. Histopathological analysis of mice intratracheally injected with this fungus was also performed. The results disclosed that the conidia of S. chartarum were resistant to the antifungal activities of alveolar macrophages in terms of phagocytosis, killing and inhibition of germination. However, the conidia could not survive in the lungs of mice when injected intratracheally. Lavage fluid of mycelia that contained the dark slimy material coating the surface of conidia showed cytotoxic activity against macrophages and PMNs. Intratracheal injection of conidia in mice resulted in intraalveolar infiltration of PMNs. When using multiple injections during a 3-week period, strong eosinophilic infiltration into the proximal alveoli and perivascular tissues was observed. Our results suggest that inhalation of conidia may cause serious damage to the human lung, particularly when repeated.     

Initial characterization of the hemolysin stachylysin from Stachybotrys chartarum

Stachybotrys chartarum is a toxigenic fungus that has been associated with human health concerns, including pulmonary hemorrhage and hemosiderosis. This fungus produces a hemolysin, stachylysin, which in its apparent monomeric form has a molecular mass of 11,920 Da as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry. However, it appears to form polydispersed aggregates, which confounds understanding of the actual hemolytically active form. Exhaustive dialysis or heat treatment at 60 degrees C for 30 min inactivated stachylysin. Stachylysin is composed of about 40% nonpolar amino acids and contains two cysteine residues. Purified stachylysin required more than 6 h to begin lysing sheep erythrocytes, but by 48 h, lysis was complete. Stachylysin also formed pores in sheep erythrocyte membranes.     

Stachybotrys chartarum: cause of human disease or media darling?

This is a review of the literature of associations of the saprotrophic fungus Stachybotrys chartarum sensu lato with human and animal illnesses. This fungus grows on very wet cellulose-based building materials. S. chartarum has been the subject of considerable media attention because of temporal associations of exposure with unexpected and dramatic outcomes such as infant pulmonary hemosiderosis and neurocognitive damage. It is generally accepted that living or working in mouldy environments is associated with building related asthma, exacerbating asthma in mould-sensitive asthmatics and increased rates of upper respiratory disease. However, such relationships are with building-associated moulds, comprising many species that colonize wet or damp building materials, and are not specific to S. chartarum. There is limited evidence that severe lung damage can occur from building exposure to S. chartarum but possibly only under conditions of exposure that approach those associated with handling contaminated straw. There is no positive evidence in the literature to account for putative neurological damage resulting from exposure to this mould.     

Inhalation of Stachybotrys chartarum causes pulmonary arterial hypertension in mice

Inhalation of Stachybotrys chartarum, a ubiquitous fungus in our living environment, has been suspected as a cause of acute idiopathic pulmonary haemorrhage in infants, but its relation to human diseases is not yet known. The aim of present study was to investigate the effect of repeated intratracheal injection of the fungus into mice, paying special attention to the pulmonary vascular system. Spores of S. chartarum were injected into the trachea of mice from 6 to 18 times over 4-12 weeks, and the lungs were examined by histopathology, morphometrics and haemodynamics. When 1 x 10(4) spores/mouse were injected, histopathological examination showed the development of pulmonary arterial hypertension (PAH). Symmetrical thickening of the intima and media of the pulmonary arterial walls was seen after six injections over 4 weeks. Right ventricular hypertrophy was also evident after 12 injections. PAH was confirmed by the elevation of right ventricular systolic pressure (20.1 +/- 5.7 mmHg in the injected group vs. 12.0 +/- 2.4 mmHg in the control group, P < 0.01). This study showed that the inhalation of S. chartarum caused PAH in mice, suggesting a potential of S. chartarum as a cause of human health problem such as PAH.     

Attributes of Stachybotrys chartarum and its association with human disease

Mold contamination and toxicities are not limited to crops and animals; they are also a concern in human health. Molds occur in outdoor and indoor environments, and water-damaged buildings harbor and provide substrate for several mold species. Of these, Stachybotrys chartarum poses a particular threat to occupants. Patients with building-related symptoms and infant idiopathic pulmonary hemorrhage often have histories of living in moldy, water-damaged buildings. Although a causal connection is far from being unequivocally proven, S. chartarum has been associated with such clinical conditions. These illnesses could be attributed in part to mycotoxins released by S. chartarum. Recently, a hemolysin released by this mold was found to be hemolytic in vitro and in vivo. In addition, allergenic proteins have been characterized from S. chartarum. The exact mechanism of S. chartarum pathogenesis has not yet been defined. Moreover, a causality-effect relation is not yet established. This review summarizes available information on the pathogenic attributes of S. chartarum and calls for well-controlled objective studies.     

Indoor mold,toxigenic fungi,and Stachybotrys chartarum: infectious disease perspective

Damp buildings often have a moldy smell or obvious mold growth; some molds are human pathogens. This has caused concern regarding health effects of moldy indoor environments and has resulted in many studies of moisture- and mold-damaged buildings. Recently, there have been reports of severe illness as a result of indoor mold exposure, particularly due to Stachybotrys chartarum. While many authors describe a direct relationship between fungal contamination and illness, close examination of the literature reveals a confusing picture. Here, we review the evidence regarding indoor mold exposure and mycotoxicosis, with an emphasis on S. chartarum. We also examine possible end-organ effects, including pulmonary, immunologic, neurologic, and oncologic disorders. We discuss the Cleveland infant idiopathic pulmonary hemorrhage reports in detail, since they provided important impetus for concerns about Stachybotrys. Some valid concerns exist regarding the relationship between indoor mold exposure and human disease. Review of the literature reveals certain fungus-disease associations in humans, including ergotism (Claviceps species), alimentary toxic aleukia (Fusarium), and liver disease (Aspergillys). While many papers suggest a similar relationship between Stachybotrys and human disease, the studies nearly uniformly suffer from significant methodological flaws, making their findings inconclusive. As a result, we have not found well-substantiated supportive evidence of serious illness due to Stachybotrys exposure in the contemporary environment. To address issues of indoor mold-related illness, there is an urgent need for studies using objective markers of illness, relevant animal models, proper epidemiologic techniques, and examination of confounding factors.     

Stachylysin may be a cause of hemorrhaging in humans exposed to Stachybotrys chartarum

Stachybotrys chartarum is a toxigenic fungus that has been associated with human health concerns such as nasal bleeding in adults and pulmonary hemosiderosis (PH) in infants. Seven of eight strains of S. chartarum isolated from homes of infants with PH in Cleveland, Ohio, and the strain from the lung of an infant with PH in Texas produced stachylysin in tryptic soy broth (TSB), whereas only one out of eight strains isolated from control homes produced stachylysin. However, all strains produced stachylysin when grown on TSB with 0.7% sheep's blood. When stachylysin was injected into Lumbricus terrestis, the erythrocruorin hemoglobin (absorbance peaks at 280 and 415 nm) was released, resulting in a lethal effect. These results support the hypothesis that stachylysin may be one agent responsible for hemorrhaging in humans.     

Localization of satratoxin-G in Stachybotrys chartarum spores and spore-impacted mouse lung using immunocytochemistry

Satratoxin-G (SG) is the major macrocyclic trichothecene mycotoxin produced by Stachybotrys chartarum (atra) and has been implicated as a cause of a number of animal and human health problems including pulmonary hemorrhage in infants. However, there is little understanding where this toxin is localized in the spores and mycelial fragments of this species or in the lung impacted by SG-sequestered spores. The purpose of this study was to evaluate the distribution of SG in S. chartarum spores and mycelium in culture, and spore-impacted mouse lung in vivo, using immunocytochemistry. SG was localized predominately in S. chartarum spores with moderate labelling of the phialide-apex walls. Labelling was primarily along the outer plasmalemma surface and in the inner wall layer. Only modest labelling was observed in hyphae. Toxin localization at these sites supports the position that spores contain the highest satratoxin concentrations and that the toxin is constitutively produced. In impacted mouse lung, highest SG labelling was detected in lysosomes, along the inside of the nuclear membrane in nuclear heterochromatin and RER within alveolar macrophages. Alveolar type II cells also showed modest labelling of the nuclear heterochromatin and RER. There was no evidence that the toxin accumulated in the neutrophils, fibroblasts, or other cells associated with the granulomas surrounding spores or mycelial fragments. These observations indicate that SG displays a high degree of cellular specificity with respect to its uptake in mouse lung. They further indicate that the alveolar macrophages play an important role in the sequestration and immobilization of low concentrations of the toxin.     

Partial amino acid sequence of a cellulase-like component with IgE-binding properties from Stachybotrys chartarum

BACKGROUND: The aim of this study was to characterize the amino acid sequence of a selected Stachybotrys chartarum component and to investigate human IgE reactivity against components of S. chartarum and nine other fungal species. METHODS: Human IgE reactivity against S. chartarum and nine other fungal extracts was investigated by the immunoblotting method. For automated amino acid sequencing analyses, the S. chartarum extract was purified by ion exchange chromatography prior to in-gel alkylation and digestion with modified trypsin. RESULTS: Human IgE reactivity was detected against eight components in the S. chartarum extract. Over 80% of the sera from the exposed subjects and less than 50% of the control sera recognized the 33-, 48- and 50-kD S. chartarum components. The human sera detected a 48- to 50-kD component from the extracts of eight fungal species. Nineteen peptide sequences were identified from the 48-kD component of S. chartarum. An analysis of the peptide sequences revealed homology with known fungal glycoside hydrolase enzymes (cellulases). CONCLUSIONS: The data showed human IgE reactivity against several S. chartarum components, including one at 48 kD. On the other hand, the human sera recognized 48- to 50-kD components from seven other fungal species, suggesting shared antigenic components (e.g. enolase) between the fungi. Thus, to our knowledge, this is the first antigen identified from S. chartarum.     

Isolation and Properties of Stachyrase A, a Chymotrypsin-Like Serine Proteinase from Stachybotrys chartarum

A strain of the common mold Stachybotrys chartarum has been isolated from the lung of a child with pulmonary hemorrhage. We report the purification of stachyrase A, a new serine chymotrypsin-like proteinase from S. chartarum. This enzyme cleaves major protease inhibitors, several biologically active peptides, and collagen, all of which are found in the lung.     

A structural basis for food allergy: the role of cross-reactivity

PURPOSE OF REVIEW: Immunologic cross-reactivity, which is important in many aspects of host defense and immune-mediated diseases, is a prominent feature of allergic disorders. The goal of this article is to define allergenic cross-reactivity and its role in food allergy, review current understanding of mechanisms of cross-reactivity, and consider how advances in our ability to predict cross-reactivity can impact diagnosis and treatment of food allergy. RECENT FINDINGS: Recent evidence suggests that specific T cells, in addition to IgE, developed in response to inhaled allergens can cross-react with related food allergens, leading to distinct clinical reactions. Several new cross-reactivities have been identified, including food-food, pollen-food, and latex-venom associations. Debate continues regarding prediction of allergenicity based on protein structure, and clinical relevance of in-vitro testing. Cross-reactivity is also being used to develop specific immunotherapy for treatment of food allergy. SUMMARY: A thorough understanding of immunologic cross-reactivity is essential to advancing our knowledge about food allergy. This knowledge will help elucidate the pathogenesis of the disorder and prevent exposures to allergenic, genetically engineered foods. New insight will allow for better utilization of current diagnostic tools and the development of more accurate tests and therapies for food allergy.     

Characterization of monoclonal antibodies to an antigenic protein from Stachybotrys chartarum and its measurement in house dust

Using sera from atopic patients we have isolated an extracellular protein, which is antigenic in humans, from Stachybotrys chartarum sesu lato. Here we report the production of monoclonal antibodies to the protein and the development of a sensitive and specific assay to the target protein as well as analyses in house dust samples spiked with spores. The detection limit for the target antigen in house dust was approximately 0.2 ng/g dry weight house dust. This detection limit is comparable to those for house dust mite allergen and the allergen of the fungus Aspergillus fumigatus but lower than that for the fungus Alternaria alternata.     

Satratoxin-G from the Black Mold Stachybotrys chartarum Induces Rhinitis and Apoptosis of Olfactory Sensory Neurons in the Nasal Airways of Rhesus Monkeys

Satratoxin-G (SG) is a trichothecene mycotoxin of Stachybotrys chartarum, the black mold suggested to contribute etiologically to illnesses associated with water-damaged buildings. We have reported that intranasal exposure to SG evokes apoptosis of olfactory sensory neurons (OSNs) and acute inflammation in the nose and brain of laboratory mice. To further assess the potential human risk of nasal airway injury and neurotoxicity, we developed a model of SG exposure in monkeys, whose nasal airways more closely resemble those of humans. Adult, male rhesus macaques received a single intranasal instillation of 20 μg SG (high dose, n = 3), or 5 μg SG daily for four days (repeated low dose, n = 3) in one nasal passage, and saline vehicle in the contralateral nasal passage. Nasal tissues were examined using light and electron microscopy and morphometric analysis. SG induced acute rhinitis, atrophy of the olfactory epithelium (OE), and apoptosis of OSNs in both groups. High-dose and repeated low-dose SG elicited a 13% and 66% reduction in OSN volume density, and a 14-fold and 24-fold increase in apoptotic cells of the OE, respectively. This model provides new insight into the potential risk of nasal airway injury and neurotoxicity caused by exposure to water-damaged buildings.     

The role of the epitope density and cross-reactivity between two different purine nucleosides coupled to cells

Cellular immune responses against nucleic acid antigens were analyzed in BALB/C mice. Delayed-type hypersensitivity (DTH) could be elicited by immunizing and challenging with either guanosine-coupled spleen cells (G-SC) or adenosine-coupled spleen cells (A-SC), and measured by footpad swellings. The epitope density was critical for immunization. This cellular reaction was specific to nucleosides, and cross-immunity was observed between A-SC and G-SC. In addition, cross-unresponsiveness was observed between these two nucleosides. In contrast, soluble carrier proteins coupled with either guanosine or adenosine did not induce cross-reactive immunity or unresponsiveness. The significance of the difference between these two forms of antigens in the ability to induce cross-reactivity is discussed in the context of T versus B-cell recognition in the induction or the expression of the immune response.     

Interpretation of the cross-reactivity of anti-DNA antibodies with cell surface proteins: the role of cell surface histones

The putative cross-reaction of anti-DNA antibodies with "lupus-associated membrane proteins (LAMP)" on the surface of intact Raji cells was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analyses. Cell surface proteins of 14, 17, 18, 33 and 34 kDa were detected by monoclonal anti-double-stranded (ds) DNA antibodies and the sera of patients with systemic lupus erythematosus (SLE) in active states, but were not detected by the sera of SLE patients in inactive states, nor in healthy controls. However, pre-treatment of these anti-DNA antibodies with DNase I markedly reduced the reactivity to the cell surface proteins. Judging from the electrophoretic mobility, these proteins were identical with histones, and purified histones inhibited the reaction of anti-DNA antibodies with the cell surface proteins. Moreover, affinity-purified antihistone antibodies could demonstrate histones in the Raji cell surface proteins. Thus, we conclude that "cross-reaction" of anti-DNA antibodies with LAMP is due to DNA-anti-DNA immune complexes which could react with cell surface histones.     

Software for the analysis of species-specific vocalizations

Vocalization calls are behaviorally relevant complex sounds that typically contain several harmonics and show frequency and amplitude modulation. In this paper, an introduction to a software tool for the analysis of species-specific vocalizations is presented. The algorithm automatically or under user supervision detects time-varying amplitude and frequency parameters, which can serve for the statistical analysis of calls or as the substrate for the manipulation and synthesis of artificial calls. The described program and its results will be used in studying the representation of complex sounds in the central nervous system.     

The role of heparan sulphate in development: the ectodermal story

Heparan sulphate (HS) is ubiquitously expressed and is formed of repeating glucosamine and glucuronic/iduronic acid units which are generally highly sulphated. HS is found in tissues bound to proteins forming HS proteoglycans (HSPGs) which are present on the cell membrane or in the extracellular matrix. HSPGs influence a variety of biological processes by interacting with physiologically important proteins, such as morphogens, creating storage pools, generating morphogen gradients and directly mediating signalling pathways, thereby playing vital roles during development. This review discusses the vital role HS plays in the development of tissues from the ectodermal lineage. The ectodermal layer differentiates to form the nervous system (including the spine, peripheral nerves and brain), eye, epidermis, skin appendages and tooth enamel.