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BACKGROUND: Exposures to indoor biological contaminants have been implicated in asthma's aetiology but their effect on lung function is not well quantified. OBJECTIVE: The aim of this cross-sectional study of non-smoking, asthmatic adults in Scotland was to determine the correlation between the results from a standard spirometry test, forced expiratory volume in one-second percent (FEV1 %), and quantitative estimates of some biological exposures. METHODS: A population (n = 55) of non-smoking, adult asthmatics in Scotland was included in this study and each completed a questionnaire that allowed the determination of the Asthma Control Questionnaire scores (ACQ) and St. George's Respiratory Questionnaire scores (SGRQ), as well as corticosteroid use. Spirometry testing was completed and the pre-bronchodilator FEV1 % value calculated. At about the same time, floor dust samples were collected in the living room and in the bedroom. These dust samples were analysed for mould contamination, as described by the Environmental Relative Moldiness Index (ERMI) values and by (1, 3)-ß-D-glucan concentrations, for endotoxin, and for dust mite, cat, and dog allergen concentrations. The asthmatics' FEV1 % values were tested for correlation (Pearson) to questionnaire-based estimates of health. Also, each biological exposure was tested for correlation (Pearson) to the FEV1 % values. RESULTS: FEV1 % results were correlated with ACQ scores (ρ -0.586, P < 0.001), SGRQ scores (ρ -0.313, P = 0.020), and weakly with corticosteroid use (ρ -0.221, P = 0.105). The ERMI values in the homes (average 5.3) were significantly correlated with FEV1 % values (ρ -0.378, P = 0.004). There was no correlation between FEV1 % and concentrations of endotoxin, (1, 3)-ß-D-glucan, or any of the allergens. CONCLUSION AND CLINICAL RELEVANCE: Although these results do not prove that mould exposures caused the deficit in lung function observed in this study, it might be advisable for asthmatics to avoid high ERMI environments.
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Microbiología del Aire , Contaminación del Aire Interior , Asma/epidemiología , Asma/fisiopatología , Volumen Espiratorio Forzado , Hongos , Vivienda , Adulto , Anciano , Alérgenos , Animales , Comorbilidad , Estudios Transversales , Polvo/análisis , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escocia/epidemiología , Encuestas y Cuestionarios , Adulto JovenRESUMEN
Possible relationships between mold contamination, as described by the Environmental Relative Moldiness Index (ERMI), home characteristics, and the development of wheeze in the first year of life were evaluated among a cohort of urban infants (n = 103) in Syracuse, New York. Pregnant women with a history of asthma were recruited in 2001-2002 for the "Assessment of Urban Dwellings for Indoor Toxics" (AUDIT) study. When the infants were approximately 3 months of age, a home inspection was carried out and indoor environmental samples collected, including vacuumed house dust. ERMI levels in the Syracuse cohort homes were higher than the U.S. average, with an overall mean of 11.4. ERMI levels were significantly higher in homes with visible water problems (p = 0.023) and visible mold (p = 0.023). ERMI levels in apartments were significantly lower than the values measured in houses (p = 0.0003). While infants experiencing wheeze (38%) tended to live in homes with higher ERMI values than those without wheeze (ERMI values of 12.3 and 10.9, respectively), the differences did not reach statistical significance. A subset analysis limited to infants with living room samples who remained in the same home during the study (n = 25) was suggestive of an association between higher ERMI values and wheeze (p = 0.10). In summary, the ERMI is a standardized metric which allows for comparison of moldiness levels in homes across studies and regions in the United States. ERMI levels in Syracuse homes were skewed to the high end of the national scale. Higher ERMI levels were indicators of water problems, mold, and type of housing.
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Microbiología del Aire/normas , Contaminación del Aire Interior/análisis , Polvo/análisis , Hongos/crecimiento & desarrollo , Vivienda/estadística & datos numéricos , Ruidos Respiratorios , Adulto , Contaminación del Aire Interior/estadística & datos numéricos , Asma/epidemiología , Femenino , Hongos/aislamiento & purificación , Humanos , Lactante , Masculino , New York/epidemiología , EmbarazoRESUMEN
Respiratory illnesses have been linked to children's exposures to water-damaged homes. Therefore, understanding the microbiome in water-damaged homes is critical to preventing these illnesses. Few studies have quantified bacterial contamination, especially specific species, in water-damaged homes. We collected air and dust samples in twenty-one low-mold homes and twenty-one high-mold homes. The concentrations of three bacteria/genera, Stenotrophomonas maltophilia, Streptomyces sp., and Mycobacterium sp., were measured in air and dust samples using quantitative PCR (QPCR). The concentrations of the bacteria measured in the air samples were not associated with any specific home characteristic based on multiple regression models. However, higher concentrations of S. maltophilia in the dust samples were associated with water damage, that is, with higher floor surface moisture and higher concentrations of moisture-related mold species. The concentrations of Streptomyces and Mycobacterium sp. had similar patterns and may be partially determined by human and animal occupants and outdoor sources of these bacteria.
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Microbiología del Aire , Hongos/aislamiento & purificación , Mycobacterium/aislamiento & purificación , Stenotrophomonas maltophilia/aislamiento & purificación , Streptomyces/aislamiento & purificación , Polvo , Reacción en Cadena de la Polimerasa , Análisis de RegresiónRESUMEN
Hurricane Maria struck Puerto Rico on September 20, 2017, severely impacting the island. In order to quantify the impact of the hurricane on the indoor air quality, we evaluated the fungal levels in households (n = 20) of the Piñones community for the period of 2018 and 2019. For each dust sample collected, the 36 Environmental Relative Moldiness Index (ERMI) molds were quantified using qPCR assays, and then Shannon Diversity Index (SDI) values for the fungal populations were calculated. Homes were in five separate regions, regarding their proximity in the studied area. We found that for regions with reported least water damage, the SDI values were similar for both sampled years, but for regions that reported mid-to-high level of damage region, the SDI values were significantly higher. Households that reported remediation actions between the two sampled years showed similar values for the second year as those that did not report any major impact. Our preliminary data provides insights into the significant impacts of hurricanes into indoor fungal environment.
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In addition to mold, indoor bioaerosols also contain bacterial components that may have implications for human health. Endotoxin is a cell wall component in Gram-negative bacteria present at varying levels indoors that has been found to have respiratory health implications. Streptomyces is a large genus of Gram-positive bacteria, and some species have been shown to produce inflammatory reactions in vitro and in vivo. The aim of this study was to determine predictors of streptomycetes levels in house dust and to compare the variation in streptomycetes levels with that in endotoxin levels. Dust was collected by floor vacuuming from 178 homes in the Cincinnati metropolitan area. Streptomycetes levels were measured by quantitative PCR, and endotoxin was assayed by the Limulus amebocyte lysate method. Associations between home characteristics and bacterial contaminants, expressed as concentration and load, were investigated through multiple regression analyses. The presence of two or more dogs was a strong predictor of both streptomycetes and endotoxin levels. Season of dust collection and levels of outdoor molds were predictors of streptomycetes but not endotoxin levels. In contrast, number of inhabitants was a significant predictor of endotoxin load only. Neither streptomycetes nor endotoxin levels were associated with metrics of moisture damage.
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Contaminación del Aire Interior/análisis , Polvo/análisis , Endotoxinas/análisis , Monitoreo del Ambiente/métodos , Vivienda , Streptomyces/aislamiento & purificación , Animales , Animales Domésticos , Ciudades , Perros , Humanos , Humedad , Ohio , Valor Predictivo de las Pruebas , Medición de Riesgo/métodos , Estaciones del Año , Streptomyces/crecimiento & desarrollo , Temperatura , Agua/químicaRESUMEN
AIMS: To screen for the virulence potential of Aeromonas isolates based on the change in regulation of c-jun and c-fos in the human intestinal tissue culture cell line Caco-2. METHODS AND RESULTS: Aeromonas cells were added to Caco-2 cells at a ratio of approx. 1 : 1. After 1-, 2- and 3-h incubation at 37 degrees C, mRNA was extracted from the cells and gene expression of two host genes, c-jun and c-fos, quantified. Aeromonas isolates which were pathogenic in the neonatal mouse model demonstrated up-regulation of c-jun and c-fos compared to avirulent isolates. CONCLUSIONS: Human cell culture results showed that c-jun and c-fos were predictive of Aeromonas virulence. SIGNIFICANCE AND IMPACT OF THE STUDY: An Aeromonas relative virulence scale is proposed for use in the testing of Aeromonas drinking water isolates.
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Aeromonas/aislamiento & purificación , Aeromonas/patogenicidad , Células CACO-2/microbiología , Virulencia , Aeromonas/genética , Aeromonas/metabolismo , Animales , Animales Recién Nacidos , Células Cultivadas , Modelos Animales de Enfermedad , Expresión Génica , Perfilación de la Expresión Génica/métodos , Regulación de la Expresión Génica , Humanos , Intestino Delgado/microbiología , Ratones , Reacción en Cadena de la Polimerasa/métodos , Valor Predictivo de las Pruebas , Proteínas Proto-Oncogénicas c-fos/genética , Proteínas Proto-Oncogénicas c-jun/genética , ARN Mensajero/genética , Microbiología del Agua , Abastecimiento de AguaRESUMEN
UNLABELLED: Indoor exposure to fungi has been associated with respiratory symptoms,often attributed to their cell wall component, (1-3)-beta-D-glucan. Performing(1-3)-beta-D-glucan analysis is less time consuming and labor intensive than cultivation or microscopic counting of fungal spores. This has prompted many to use(1-3)-beta-D-glucan as a surrogate for fungal exposure. The aim of this study was to examine which indoor fungal species are major contributors to the (1-3)-beta-D-glucan concentration in field dust samples. We used the quantitative polymerase chain reaction (QPCR) method to analyze 36 indoor fungal species in 297 indoor dust samples. These samples were also simultaneously analyzed for (1-3)-beta-D-glucan concentration using the endpoint chromogenic Limulus Amebocyte lysate assay. Linear regression analysis, followed by factor analysis and structural equation modeling, were utilized in order to identify fungal species that mostly contribute to the (1-3)-beta-D-glucan concentration in field dust samples. The study revealed that Cladosporium and Aspergillus genera, as well as Epicoccum nigrum, Penicillium brevicompactum and Wallemia sebi were the most important contributors to the (1-3)-beta-D-glucan content of these home dust samples. The species that contributed most to the (1-3)-beta-D-glucan concentration were also the most prevalent in indoor environments. However, Alternaria alternata, a common fungal species in indoor dust, did not seem to be a significant source of (1-3)-beta-D-glucan. PRACTICAL IMPLICATIONS: This study revealed that the (1-3)-beta-D-glucan content of different fungal species varies widely. (1-3)-beta-D-glucan inhouse dust from the Greater Cincinnati area may be a good marker for some fungal species of the Cladosporium and Aspergillus genera. In contrast, Alternaria alternata did not contribute much to the (1-3)-beta-D-glucan load. Therefore, (1-3)-beta-D-glucan concentration in field samples as a surrogate for total fungal exposure should be used with caution.
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Microbiología del Aire , Contaminación del Aire Interior/análisis , Polvo/análisis , Exposición a Riesgos Ambientales/análisis , Hongos/aislamiento & purificación , beta-Glucanos/análisis , Monitoreo del Ambiente/métodos , HumanosRESUMEN
Opportunistic fungal pathogens are a concern because of the increasing number of immunocompromised patients. The goal of this research was to test a simple extraction method and rapid quantitative PCR (QPCR) measurement of the occurrence of potential pathogens, Aspergillus fumigatus, A. flavus, A. terreus and A. niger, in home tap water and a hospital water supply. Water samples were taken from the kitchen tap in the homes of 60 patients who were diagnosed with legionellosis. Water samples were also taken from three locations in a hospital that generated all of its hot water by flash heating. Opportunistic infectious agents Aspergillus fumigatus, A. flavus, A. terreus and A. niger were measured using QPCR. Aspergillus terreus DNA was found in 16.7% and A. fumigatus DNA in 1.7% of the samples taken from the kitchen tap. None of the Aspergillus species were found in any of the hospital water samples.The development of a simple DNA extraction method along with QPCR analysis is suitable for rapid screening of tap water for opportunistic fungal pathogens. This simple method can be used to obtain pathogen occurrence results in about 3 h, instead of waiting days to weeks for culture data. Obtaining pathogen occurrence data in a timely manner could promote the elimination of the pathogens from the water supply of immunocompromised patients.
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Aspergillus/genética , Aspergillus/aislamiento & purificación , ADN de Hongos/aislamiento & purificación , Contaminantes del Agua/aislamiento & purificación , Abastecimiento de Agua/análisis , ADN de Hongos/genética , Monitoreo del Ambiente/métodos , Hospitales , Vivienda , Reacción en Cadena de la PolimerasaRESUMEN
The goal of this study was to examine whether the Environmental Relative Moldiness Index (ERMI) scale created for United States (U.S.) homes was applicable in the assessment of mold contamination for Australian homes. Settled-dust samples were collected in south-eastern Australian homes (n=76) being investigated for possible water-damage and mold contamination. The 36 ERMI molds were quantified in each sample using mold specific quantitative PCR (MSQPCR) and the ERMI value for each home calculated. These homes were then matched to homes in the U.S. with nearly identical ERMI values and the average log10 concentration of each of the 36 molds statistically compared. Most of the 36 ERMI molds were found in Australian water-damaged homes in comparable concentrations to ERMI-matched U.S. homes. The U.S. ERMI scale might provide reasonable estimates of mold contamination in water-damaged Australian homes.
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During the enlargement of an existing hospital, quantitative polymerase chain reaction (PCR) was used to monitor Aspergillus spp. populations within the construction site. The rapid availability of results meant that the construction schedule was largely uninterrupted, while assuring that the new construction was free from contamination by the targeted Aspergillus spp.
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Aspergillus/aislamiento & purificación , ADN de Hongos/genética , Monitoreo del Ambiente/métodos , Arquitectura y Construcción de Hospitales , Reacción en Cadena de la Polimerasa , Aspergillus/genética , Materiales de Construcción/microbiología , Contaminación de Equipos/prevención & control , Estudios de Evaluación como Asunto , Estados UnidosRESUMEN
Analyses of fungal spores or conidia in indoor dust samples can be useful for determining the contamination status of building interiors and in signaling instances where potentially harmful exposures of building occupants to these organisms may exist. A recently developed method for the quantification of Stachybotrys chartarum conidia, using real-time, fluorescence probe--based detection of PCR products (TaqMan system) was employed to analyze indoor dust samples for this toxigenic fungal species. Dust samples ofup to 10 mg were found to be amenable to DNA extraction and analysis. Quantitative estimates of S. chartarum conidia in composite dust samples, containing a four-log range of these cells, were within 25 -- 104% of the expected quantities in 95% of analyses performed by the method. Calibrator samples containing known numbers of S. chartarum conidia were used as standards for quantification. Conidia of an arbitrarily selected strain of Geotrichum candidum were added in equal numbers to both dust and calibrator samples before DNA extraction. Partial corrections for reductions in overall DNA yields from the dust samples compared to the calibrator samples were obtained by comparative analyses of rDNA sequence yields from these reference conidia in the two types of samples. Dust samples from two contaminated homes were determined to contain greater than 10(3) S. chartarum conidia per milligram in collection areas near the sites of contamination and greater than 10(2) conidia per milligram in several areas removed from these sites in analyses performed by the method. These measurements were within the predicted range of agreement with results obtained by direct microscopic enumeration of presumptive Stachybotrys conidia in the same samples.
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Contaminación del Aire Interior/análisis , ADN de Hongos/análisis , Monitoreo del Ambiente/métodos , Reacción en Cadena de la Polimerasa , Stachybotrys , Polvo , Sensibilidad y EspecificidadRESUMEN
Dust samples (n=75) were collected from shopping malls, hotels and libraries in Singapore and then analyzed using Mold Specific Quantitative Polymerase Chain Reaction (MSQPCR) for the 36 molds that make up the Environmental Relative Moldiness Index (ERMI). Most of these molds (23/36) occur at similar rates in Singapore and the United States. A Singapore Environmental Relative Moldiness Index (SERMI) is proposed which might be divided into low (<18), medium (18 to 28) and high (>28) mold burden categories but more samples will help to refine these categories.
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ADN de Hongos/genética , ADN de Hongos/aislamiento & purificación , Microbiología Ambiental , Hongos/clasificación , Hongos/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa , Hongos/genética , Humanos , SingapurRESUMEN
AIMS: To assess the virulence of Aeromonas spp. using two models, a neonatal mouse assay and a mouse intestinal cell culture. METHODS AND RESULTS: After artificial infection with a variety of Aeromonas spp., mRNA extracts from the two models were processed and hydridized to murine microarrays to determine host gene response. Definition of virulence was determined based on host mRNA production in murine neonatal intestinal tissue and mortality of infected animals. Infections of mouse intestinal cell cultures were then performed to determine whether this simpler model system's mRNA responses correlated to neonatal results and therefore be predictive of virulence of Aeromonas spp. Virulent aeromonads up-regulated transcripts in both models including multiple host defense gene products (chemokines, regulation of transcription and apoptosis and cell signalling). Avirulent species exhibited little or no host response in neonates. Mortality results correlated well with both bacterial dose and average fold change of up-regulated transcripts in the neonatal mice. CONCLUSIONS: Cell culture results were less discriminating but showed promise as potentially being able to be predictive of virulence. Jun oncogene up-regulation in murine cell culture is potentially predictive of Aeromonas virulence. SIGNIFICANCE AND IMPACT OF THE STUDY: Having the ability to determine virulence of waterborne pathogens quickly would potentially assist public health officials to rapidly assess exposure risks.
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Aeromonas/patogenicidad , Infecciones por Bacterias Gramnegativas/microbiología , Virulencia , Aeromonas/clasificación , Aeromonas/genética , Animales , Animales Recién Nacidos , Células Cultivadas , Modelos Animales de Enfermedad , Perfilación de la Expresión Génica/métodos , Regulación Bacteriana de la Expresión Génica , Humanos , Intestino Delgado/microbiología , Ratones , Ratones Transgénicos , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Regulación hacia Arriba , Microbiología del AguaRESUMEN
AIMS: To compare the populations of 81 mould species in homes in the USA and UK using mould-specific quantitative polymerase chain reaction (MSQPCR) technology. METHODS AND RESULTS: Dust samples were obtained from randomly selected homes in the UK (n=11). The mould populations in British homes were compared with those found in typical homes (no visible mould) in the USA (in the state of Ohio, n=45). Only 13 of 81 species screened showed significantly different concentrations in these two sets of home. CONCLUSIONS: Although only a small survey, the results suggest that typical mould profiles in the USA (Ohio) and British homes are very similar. Analysis of 26 mould indicator species revealed that the British homes fell into two clusters, tentatively identified as 'atypical' and 'typical' mould conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: MSQPCR analysis of dust samples can provide an objective measure of indoor moulds which could lead to better management of their health effects.
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Contaminación del Aire Interior , Hongos/clasificación , Hongos/aislamiento & purificación , Vivienda , Reacción en Cadena de la Polimerasa/métodos , Hongos/fisiología , Humanos , Especificidad de la Especie , Esporas Fúngicas/aislamiento & purificación , Reino Unido , Estados UnidosRESUMEN
Pseudomonas fluorescens isolates 13525 and 2-79 were grown in Luria broth and low-nutrient medium (LNM). Pililike fibrils were very rarely produced in Luria broth but were abundantly produced in LNM. In LNM the pili were peritrichously distributed and had diameters ranging from 3 to 8 nm. Pili were purified from strain 2-79, and the pilin subunit was found to have a molecular weight of about 34,000. Strain 2-79 produced two colony types on Luria agar, nonmucoidal and mucoidal. Cells in LNM cultures of the nonmucoidal colony type were highly piliated, and cells from the mucoidal type were nearly devoid of pili. The presence of pili on nonmucoidal isolate 2-79 was quantitatively correlated with hydrophobic attachment to polystyrene, hemagglutination, and attachment to corn roots.
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Pili (fimbriae) were observed on cells of each of the five strains of Bradyrhizobium japonicum and the one strain of Rhizobium trifolii examined. Pili on B. japonicum were about 4 nm in diameter and polarly expressed. Piliated cells were estimated by transmission electron microscopy and hydrophobic attachment to polystyrene to constitute only a small percentage of the total population. The proportion of piliated cells in these populations was dependent on culture age in some strains. Piliated B. japonicum cells were selectively and quantitatively removed from suspension when cultures were incubated with either soybean roots or hydrophobic plastic surfaces, indicating that pili were involved in the attachment of the bacteria to these surfaces. Pili from B. japonicum 110 ARS were purified and found to have a subunit molecular weight of approximately 21,000. Treatment of B. japonicum suspensions with antiserum against the isolated pili reduced attachment to soybean roots by about 90% and nodulation by about 80%. Pili appear to be important mediators of attachment of B. japonicum to soybean roots under the conditions examined.
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Transposon mutants of Bradyrhizobium japonicum 110 ARS were produced and screened for changes in attachment ability. Mutant CFK4 produced twice as many piliated cells, attached in 2.5-fold-higher numbers to soybean root segments, and colonized roots in about 2-fold-higher numbers than did the parental strain, 110 ARS. Mutants CFK35 and CFK38 were reduced in their attachment about 2-fold and 3.5-fold, respectively. This corresponded to reductions in piliated cells in their populations, reduced reaction with anti-pilus antiserum, and reduced hydrophobic attachment. Mutants CFK4 and CFK38 nodulated soybeans at about the same level as the parent strain, but CFK35 induced only pseudonodules. Two-dimensional gel analyses of the proteins from the mutants showed relatively few changes in proteins.
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The occurrence of Stachybotrys chartarum in indoor environments has been associated with a number of human health concerns, including fatal pulmonary haemosiderosis in infants. Currently used culture-based and microscopic methods of fungal species identification are poorly suited to providing quick and accurate estimates of airborne human exposures to the toxin containing conidia of this organism. In this study, real-time polymerase chain reaction (PCR) product analysis using the TaqManU fluorogenic probe system and an Applied Biosystems PrismS model 7700 sequence detection instrument (model 7700) was applied to the specific detection of S. chartarum ribosomal DNA (rDNA) sequences. Based upon this assay and a recently reported comparative cycle threshold method for quantifying target DNA sequences using data from the model 7700, a simple method for the direct quantification of S. chartarum conidia was developed. In analyses of samples containing several different strains and from two to over 2x10(5)cells, this method consistently provided quantitative estimates of S. chartarum conidia that were within a one-fold range (50-200%) of those determined on the basis of direct microscopic counts in a haemocytometer. The method showed a similar level of agreement with direct counting in the quantification of S. chartarum conidia in air samples collected from several contaminated homes.
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ADN de Hongos/análisis , Stachybotrys/genética , Contaminación del Aire Interior/análisis , Secuencia de Bases , Cartilla de ADN , ADN Ribosómico/análisis , Microbiología Ambiental , Colorantes Fluorescentes , Reacción en Cadena de la Polimerasa , Sensibilidad y EspecificidadRESUMEN
Stachybotrys chartarum is an indoor air, toxigenic fungus that has been associated with a number of human and veterinary health problems. Most notable among these has been a cluster of idiopathic pulmonary hemorrhage cases that were observed in the Cleveland, Ohio, area. In this study, 16 strains of S. chartarum isolated from case (n = 8) or control (n = 8) homes in Cleveland and 12 non-Cleveland strains from diverse geographic locations were analyzed for hemolytic activity, conidial toxicity, and randomly amplified polymorphic DNA banding patterns. In tests for hemolytic activity, strains were grown at 23 degrees C on wet wallboard pieces for an 8-week test period. Conidia from these wallboard pieces were subcultured on sheep's blood agar once a week over this period and examined for growth and clearing of the medium at 37 or 23 degrees C. Five of the Cleveland strains (all from case homes) showed hemolytic activity at 37 degrees C throughout the 8-week test compared to 3 of the non-Cleveland strains. Five of the Cleveland strains, compared to two of the non-Cleveland strains, produced highly toxic conidia (>90 microgram of T2 toxin equivalents per g [wet weight] of conidia) after 10 and 30 days of growth on wet wallboard. Only 3 of the 28 strains examined both were consistently hemolytic and produced highly toxic conidia. Each of these strains was isolated from a house in Cleveland where an infant had idiopathic pulmonary hemorrhage.
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Vivienda , Enfermedades Pulmonares Fúngicas/microbiología , Técnica del ADN Polimorfo Amplificado Aleatorio , Stachybotrys/aislamiento & purificación , Stachybotrys/patogenicidad , ADN Bacteriano/análisis , Brotes de Enfermedades , Hemólisis , Hemorragia/microbiología , Humanos , Lactante , Recién Nacido , Enfermedades Pulmonares Fúngicas/epidemiología , Micotoxinas/toxicidad , Ohio/epidemiología , Filogenia , Reacción en Cadena de la Polimerasa , Stachybotrys/clasificación , Stachybotrys/genética , VirulenciaRESUMEN
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.