Inflammatory responses in mice after intratracheal instillation of spores of Streptomyces californicus isolated from indoor air of a moldy building

Biosafety measures for Alicyclobacillus spp. strains across various levels of biohazard

Alicyclobacillus bacteria are important contaminants in the beverage industry because their spores remain in the product after usual pasteurization. At the same time, their impact on human health has yet to be characterized, as it is generally assumed to be low or non-existent. However, these bacteria are causing quality concerns mainly due to odor and taste changes of the product. Since potential health effects are not precisely known, an experimental assessment was performed, including a biosafety assessment of six viable and non-viable vegetative and spore forms of Alicyclobacillus spp. strains using cell cultures and rodent study. The monolayer of Caco-2 (Cancer coli-2) cells was investigated for its adsorption effect on the epithelium of the small intestine of mice. Lactate dehydrogenase leakage (LDH) and transepithelial electrical resistance (TEER) tests were used to ensure the integrity of the cell membrane and tight junctions. The methylthiazole tetrazolium bromide (MTT) assay examined in vitro cytotoxicity in Caco-2 and HepG2 cell lines. The hemolysis of erythrocytes was spectrophotometrically measured. The results showed negligible cytotoxicity or non-toxic response in mice. In conclusion, Alicyclobacillus spp. exhibited biocompatibility with negligible cytotoxicity and minimal safety concerns.

Identification of environmental Actinobacteria in buildings by means of chemotaxonomy, 16S rRNA sequencing, and MALDI-TOF MS

Actinobacteria are abundant in soil and other environmental ecosystems and are also an important part of the human microbiota. Hence, they can also be detected in indoor environments and on building materials, where actinobacterial proliferation on damp materials can indicate moisture damage. The aim of this study was to evaluate the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for the identification of 28 environmental strains of Actinobacteria isolated from building materials and indoor and outdoor air samples, mainly collected in the context of moisture damage investigations in buildings in Finland. The 16S rRNA gene sequencing and chemotaxonomic analyses were performed, and results were compared with the MALDI-TOF MS Biotyper identification. Using 16S rRNA gene sequencing, all isolates were identified on the species or genus level and were representatives of Streptomyces, Nocardia, and Pseudonocardia genera. Based on MALDI-TOF MS analysis, initially, 11 isolates were identified as Streptomyces spp. and 1 as Nocardia carnea with a high identification score. After an upgrade in the MALDI-TOF MS in-house database and re-evaluation of mass spectra, 13 additional isolates were identified as Nocardia, Pseudonocardia, and Streptomyces. MALDI-TOF MS has the potential in environmental strain identification; however, the standard database needs to be considerably enriched by environmental Actinobacteria representatives.

IMPORTANCE

The manuscript addresses the challenges in identifying environmental bacteria using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) Biotyper-based protein profiling. The matter of the studies-actinobacterial strains-has been isolated mostly from building materials that originated from a confirmed moisture-damaged situation. Polyphasic taxonomy, 16S RNA gene sequencing, and MALDI-TOF mass spectrometry were applied for identification purposes. In this experimental paper, a few important facts are highlighted. First, Actinobacteria are abundant in the natural as well as built environment, and their identification on the species and genus levels is difficult and time-consuming. Second, MALDI-TOF MS is an effective tool for identifying bacterial environmental strains, and in parallel, continuous enrichment of the proteomics mass spectral databases is necessary for proper identification. Third, the chemical approach aids in the taxonomical inquiry of Actinobacteria environmental strains.

Indoor microbial exposure increases complement component C3a and C-reactive protein concentrations in serum

Indoor exposure to microbial growth, caused by moisture damage, has been an established health risk for several decades. It is likely that a damp indoor environment contains biological pollutants that trigger both the innate and adaptive branches of the immune system. In this study, we investigated the association between moisture damage related microbial exposure and serum C3a, C5a and CRP concentrations in Finnish adults. Serum C3a and CRP concentrations were elevated in individuals exposed to moisture damage and microbial growth in an indoor air environment. The elevated concentrations may be due to environmental factors present in moisture-damaged buildings. Complement activation and the resulting proinflammatory cleavage products may be a driving factor in inflammatory responses following exposure to indoor moisture damage and related microbial growth.

The Genome Analysis of the Human Lung-Associated Streptomyces sp. TR1341 Revealed the Presence of Beneficial Genes for Opportunistic Colonization of Human Tissues

Streptomyces sp. TR1341 was isolated from the sputum of a man with a history of lung and kidney tuberculosis, recurrent respiratory infections, and COPD. It produces secondary metabolites associated with cytotoxicity and immune response modulation. In this study, we complement our previous results by identifying the genetic features associated with the production of these secondary metabolites and other characteristics that could benefit the strain during its colonization of human tissues (virulence factors, modification of the host immune response, or the production of siderophores). We performed a comparative phylogenetic analysis to identify the genetic features that are shared by environmental isolates and human respiratory pathogens. The results showed a high genomic similarity of Streptomyces sp. TR1341 to the plant-associated Streptomyces sp. endophyte_N2, inferring a soil origin of the strain. Putative virulence genes, such as mammalian cell entry (mce) genes were not detected in the TR1341's genome. The presence of a type VII secretion system, distinct from the ones found in Mycobacterium species, suggests a different colonization strategy than the one used by other actinomycete lung pathogens. We identified a higher diversity of genes related to iron acquisition and demonstrated that the strain produces ferrioxamine B in vitro. These results indicate that TR1341 may have an advantage in colonizing environments that are low in iron, such as human tissue.

Role of Glutathione-S-transferases in neurological problems

INTRODUCTION

Role of Glutathione-S-transferases (GSTs) has been well explored in the cellular detoxification process, regulation of redox homeostasis and S-glutothionylation of target proteins like JNK, ASK1 etc. However, altered levels or functions of this enzyme or their subtypes have emerged in the development of several pathologies diseases such as Alzheimer's disease, Parkinson's disease, cancer and related conditions. Oxidative stress is one of the possible pathological events that contributes significantly to activation of degenerating cascades inside neuronal cells. The central nervous system is highly sensitive to oxidative stress because of low levels or capacities of antioxidant enzymes. The brain is highly metabolic in nature making it susceptible to oxidative stress. Areas covered: The present review provides a comprehensive overview of the multiple connections of GSTs within diverse neurological diseases including cancer. Furthermore, the authors have made significant efforts to discuss the regulation of different GST isoforms that have been associated with various pathological processes such as glioblastoma, Alzheimer's disease, Parkinson's disease, stroke and epilepsy. Expert opinion: Though GSTs have been one of the key areas of scientific research over the last few decades, much remains to be elucidated about their physiological functions as well as pathological involvement of GSTs and their polymorphic variants.

Effect of moisture-damage intervention on the immunotoxic potential and microbial content of airborne particles and on occupants' upper airway inflammatory responses

This intervention study evaluated the effect of moisture-damage repairs on the exposure and on the upper airway inflammatory responses of the occupants. The airborne microbial exposure was followed by quantitative PCR analyses of 13 microbial species in repeated long-term indoor air samples before (N = 26) and after (N = 28) repairs of the school building. Airborne particulate matter was collected similarly from the same premises (before N = 25, after N = 34) for determination of nitric oxide (NO), tumor necrosis factor α (TNFα), and interleukin-6 (IL-6), measured in the cell culture medium of mouse macrophages. NO, TNFα, IL-6, and IL-4 were also analyzed in the nasal lavage (NAL) samples of the occupants (N = 13) to characterize their upper airway inflammatory responses during the exposure and after its cessation. After the repairs, concentrations of the measured airborne microbes decreased, the difference being significant for six of 13 species. After renovation, airborne particulate matter also caused significantly lower production of IL-6 and TNF-α in mouse macrophages than the material collected before the renovation. The concentration of IL-4 in the NAL samples was significantly lower after the renovation. These results show that the inflammatory potential of the airborne material decreases after intensive repair of the moisture damage.

Expression pattern of GSTP1 and GSTA1 in the pathogenesis of asthma

Reactive oxygen species (ROS) are known aggravating factors for airway inflammation in asthma. Glutathione S-transferases (GSTs) detoxify ROS and toxic compounds in environmental exposures. However, little is known about the regulation of GST and expression of GST subtypes in asthma. The aim of this study was to evaluate how GSTs are regulated in asthma. We observed total GST activity and expression of GST subtypes in murine asthma models and GST expressions in induced sputum cells of asthmatics. Total GST activity was increased in BAL fluids of OVA-treated murine asthma model. GSTP and GSTA are highly expressed in peribronchiolar mononuclear inflammatory cells and epithelial cells in OVA-treated mice. GSTM are expressed in epithelial cells in both OVA and PBS-treated groups. GSTP1 mRNA expression was increased in the lung of OVA-treated mice compared with PBS-treated mice. GSTA1, GSTM1, and GSTT1 mRNA expressions were not different between both groups. GSTA1 mRNA expression was increased in induced sputum cells of asthmatics compared with healthy controls. GSTP1, GSTM1, and GSTT1 mRNA expressions were not different between asthmatics and healthy controls. In asthmatics, GSTP1 and GSTA1 mRNA expressions were higher in induced sputum cells of asthmatics with PC20 ≤ 4 mg/ml than those with PC20 > 4 mg/ml. GSTM1 and GSTT1 mRNA expressions were not different between two groups. These findings suggest that GSTs are upregulated in the airways of asthmatics in response to increased oxidative stress. GSTP and GSTA are thought to play an important role in protecting the airways of asthmatics compared with GSTM and GSTT.

Glutathione-S-transferase P1, early exposure to mould in relation to respiratory and allergic health outcomes in children from six birth cohorts. A meta-analysis

BACKGROUND

There are conflicting study results regarding the association of exposure to visible mould and fungal components in house dust with respiratory and allergic diseases in children. It has been suggested that functional polymorphisms of the GSTP1 gene may influence the risk for allergic disorders through an impaired defence against oxidant injury.

METHODS

We examined in six birth cohorts of over 14 000 children whether the association between early exposure to reported mould at home in relation to respiratory and allergic diseases is modified by a single nucleotide polymorphism of the GSTP1 gene.

RESULTS

We observed a positive association of mould exposure with nasal symptoms (2-10 year) aOR: 1.19 (1.02-11.38). Further, there was a borderline significant increased risk of rhinoconjunctivitis (6-8 year) in children homozygous for the minor allele Val/Val, aOR: 1.25 (0.98-1.60). In stratified analyses, subjects homozygous for the minor allele and exposed to mould at home were at increased risk for early wheezing aOR: 1.34 (1.03-1.75), whereas the major allele may confer susceptibility for later nasal outcomes, (6-8 year) aOR: 1.20 (1.00-1.45) and (2-10 year) aOR: 1.30 (1.04-1.61), respectively. For none of the health outcomes studied, we found gene by environment interactions.

CONCLUSION

A genetic influence of the GSTP1 gene cannot be ruled out, but the magnitude of the effect is a matter of further research. In conclusion, the interplay between gene and environments is complex and remains subject of further study.

Downregulation of glutathione S-transferase pi in asthma contributes to enhanced oxidative stress

BACKGROUND

Glutathione S-transferase pi (GSTPi) is the predominant redox regulator in the lung. Although evidence implicates an important role for GSTPi in asthma, the mechanism for this has remained elusive.

OBJECTIVES

We sought to determine how GSTPi is regulated in asthma and to elucidate its role in maintaining redox homeostasis.

METHODS

We elucidated the regulation of GSTPi in children with asthma and used murine models of asthma to determine the role of GSTPi in redox homeostasis.

RESULTS

Our findings demonstrate that GSTPi transcript levels are markedly downregulated in allergen- and IL-13-treated murine models of asthma through signal transducer and activator of transcription 6-dependent and independent pathways. Nuclear factor erythroid 2-related factor 2 was also downregulated in these models. The decrease in GSTPi expression was associated with decreased total glutathione S-transferase activity in the lungs of mice. Examination of cystine intermediates uncovered a functional role for GSTPi in regulating cysteine oxidation, whereby GSTPi-deficient mice exhibited increased oxidative stress (increase in percentage cystine) compared with wild-type mice after allergen challenge. GSTPi expression was similarly downregulated in children with asthma.

CONCLUSIONS

These data collectively suggest that downregulation of GSTPi after allergen challenge might contribute to the asthma phenotype because of disruption of redox homeostasis and increased oxidative stress. Furthermore, GSTPi might be an important therapeutic target for asthma, and evaluation of GSTPi expression might prove beneficial in identifying patients who would benefit from therapy targeting this pathway.

Analysis of Actinobacteria from mould-colonized water damaged building material

Mould-colonized water damaged building materials are frequently co-colonized by actinomycetes. Here, we report the results of the analyses of Actinobacteria on different wall materials from water damaged buildings obtained by both cultivation-dependent and cultivation-independent methods. Actinobacteria were detected in all but one of the investigated materials by both methods. The detected concentrations of Actinobacteria ranged between 1.8 x 10(4) and 7.6 x 10(7) CFUg(-1) of investigated material. A total of 265 isolates from 17 materials could be assigned to 31 different genera of the class Actinobacteria on the basis of 16S rRNA gene sequence analyses. On the basis of the cultivation-independent approach, 16S rRNA gene inserts of 800 clones (50%) were assigned to 47 different genera. Representatives of the genera Streptomyces, Amycolatopsis, Nocardiopsis, Saccharopolyspora, Promicromonospora, and Pseudonocardia were found most frequently. The results derived from both methods indicated a high abundance and variety of Actinobacteria in water damaged buildings. Four bioaerosol samples were investigated by the cultivation-based approach in order to compare the communities of Actinobacteria in building material and associated air samples. A comparison of the detected genera of bioaerosol samples with those directly obtained from material samples resulted in a congruent finding of 9 of the overall 35 detected genera (25%), whereas four genera were only detected in bioaerosol samples.

Seasonal variation in chemical composition of size-segregated urban air particles and the inflammatory activity in the mouse lung

We investigated the seasonal variations in the chemical composition and in vivo inflammatory activity of urban air particulate samples in four size ranges (PM(10-2.5), PM(2.5-1), PM(1-0.2), and PM(0.2)). The samples were collected in Helsinki using a high-volume cascade impactor (HVCI). Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. The lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, and keratinocyte-derived chemokine [KC]) at 4 h, and total cell number and total protein concentration at 12 h. The PM(10-2.5) and PM(2.5-1) samples had much higher inflammatory potency than the PM(1-0.2) and PM(0.2) samples. The relative inflammatory activities of the autumn samples were the highest on an equal mass basis, but when estimated for the particulate mass per cubic meter of air, the springtime samples had the highest inflammatory potential. Resuspended soil material and other non-exhaust particulate material from traffic were associated with a high inflammatory activity of the PM(10-2.5) and PM(2.5-1) samples. Secondary inorganic ions in the PM(1-0.2) and PM(0.2) samples had inconsistent negative or positive correlations with the inflammatory activity. There were no systematic seasonal variations in the tracers of incomplete combustion and atmospherically oxidized organics in the PM(1-0.2) and PM(0.2) samples, which probably explains their low correlations with the inflammatory activity. In conclusion, in a relatively clean Nordic city, the resuspension of road dust and other non-exhaust particulate material from traffic were the major sources of inflammatory activity of urban air inhalable particles.

Fungal spores: a critical review of the toxicological and epidemiological evidence as a basis for occupational exposure limit setting

Fungal spores are ubiquitous in the environment. However, exposure levels in workplaces where mouldy materials are handled are much higher than in common indoor and outdoor environments. Spores of all tested species induced inflammation in experimental studies. The response to mycotoxin-producing and pathogenic species was much stronger. In animal studies, nonallergic responses dominated after a single dose. Allergic responses also occurred, especially to mycotoxin-producing and pathogenic species, and after repeated exposures. Inhalation of a single spore dose by subjects with sick building syndrome indicated no observed effect levels of 4 x 10(3) Trichoderma harzianum spores/m(3) and 8 x 10(3) Penicillium chrysogenum spores/m(3) for lung function, respiratory symptoms, and inflammatory cells in the blood. In asthmatic patients allergic to Penicillium sp. or Alternaria alternata, lowest observed effect levels (LOELs) for reduced airway conductance were 1 x 10(4) and 2 x 10(4) spores/m(3), respectively. In epidemiological studies of highly exposed working populations lung function decline, respiratory symptoms and airway inflammation began to appear at exposure levels of 10(5) spores/m(3). Thus, human challenge and epidemiological studies support fairly consistent LOELs of approximately 10(5) spores/m(3) for diverse fungal species in nonsensitised populations. Mycotoxin-producing and pathogenic species have to be detected specifically, however, because of their higher toxicity.

The biocontaminants and complexity of damp indoor spaces: more than what meets the eyes

Nine types of biocontaminants in damp indoor environments from microbial growth are discussed: (1) indicator molds; (2) Gram negative and positive bacteria; (3) microbial particulates; (4) mycotoxins; (5) volatile organic compounds, both microbial (MVOCs) and non-microbial (VOCs); (6) proteins; (7) galactomannans; (8) 1-3-β-D-glucans (glucans) and (9) lipopolysaccharides (LPS — endotoxins). When mold species exceed those outdoors contamination is deduced. Gram negative bacterial endotoxins, LPS in indoor environments, synergize with mycotoxins. The gram positive Bacillus species, Actinomycetes (Streptomyces, Nocardia and Mycobacterium), produce exotoxins. The Actinomycetes are associated with hypersensitivity pneumonitis, lung and invasive infections. Mycobacterial mycobacterium infections not from M. tuberculosis are increasing in immunocompetent individuals. In animal models, LPS enhance the toxicity of roridin A, satratoxins G and aflatoxin B1 to damage the olfactory epithelium, tract and bulbs (roridin A, satratoxin G) and liver (aflatoxin B1). Aflatoxin B1 and probably trichothecenes are transported along the olfactory tract to the temporal lobe. Co-cultured Streptomyces californicus and Stachybotrys chartarum produce a cytotoxin similar to doxorubicin and actinomycin D (chemotherapeutic agents). Trichothecenes, aflatoxins, gliotoxin and other mycotoxins are found in dust, bulk samples, air and ventilation systems of infested buildings. Macrocyclic trichothecenes are present in airborne particles <2 μm. Trichothecenes and stachylysin are present in the sera of individuals exposed to S. chartarum in contaminated indoor environments. Haemolysins are produced by S. chartarum, Memnoniella echinata and several species of Aspergillus and Penicillium. Galactomannans, glucans and LPS are upper and lower respiratory tract irritants. Gliotoxin, an immunosuppressive mycotoxin, was identified in the lung secretions and sera of cancer patients with aspergillosis produced by A. fumigatus, A. terreus, A. niger and A. flavus.

DIRECT VISUAL INSTILLATION AS A METHOD FOR EFFICIENT DELIVERY OF FLUID INTO THE DISTAL AIRSPACES OF ANESTHETIZED MICE

Although several methods have been used to deliver fluid into the distal airspaces of the lung, the efficiency of these methods has been variable. Therefore, the authors have modified prior techniques to design a better method for direct visual instillation (DVI) of fluid into the trachea and compared its efficiency with two commonly used methods: nasal inhalation and invasive intratracheal instillation (delivery of the instillate by needle puncture of the trachea). The results showed that this method (DVI) can deliver fluid efficiently into either both lungs or into a single lung. Using an 131I-albumin labeling technique, DVI resulted in 92 +/- 1% retention of the labeled albumin in the lungs 1 hour after instillation, significantly greater than nasal inhalation (48 +/- 3%, P < .01) and invasive intratracheal instillation (77 +/- 3%, P < .05). Also, when bacteria (Escherichia coli) were instilled with the DVI method, the severity of gram-negative pneumonia was greater (6.5 +/- 0.5 g water/g dry weight) compared to delivery by nasal inhalation (5.5 +/- 0.4 g water/g dry weight, P < .05) or by invasive intratracheal instillation (5.9 +/- 0.4g water/g dry weight, P < .05). The authors conclude that DVI is more efficient than nasal inhalation and invasive intratracheal instillation for delivering experimental fluids into the distal airspaces of anesthetized mice. This method should be valuable for experimental lung studies in mice.

Associations between multiple environmental exposures and Glutathione S-Transferase P1 on persistent wheezing in a birth cohort

OBJECTIVE

To determine the impact of environmental exposures (diesel exhaust particle [DEP], environmental tobacco smoke [ETS], and mold) that may contribute to oxidative stress on persistent wheezing in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) birth cohort and to determine how the impact of these exposures is modified by the GST-P1 Ile105Val polymorphism.

STUDY DESIGN

A land-use regression model was used to derive an estimate of each child's DEP exposure. ETS exposure was determined by questionnaire data. Each child's home was evaluated for visible mold by a trained professional. Children in the CCAAPS cohort were genotyped for the GST-P1 polymorphism (n = 570). Persistent wheezing was defined as wheezing at both 12 and 24 months.

RESULTS

High DEP exposure conferred increased risk for wheezing phenotypes but only among the Val(105) allele carriers. Infants with multiple exposures were significantly more likely to persistently wheeze despite their genotype.

CONCLUSION

There is evidence for an environmental effect of DEP among carriers of the GST-P1 Val(105) allele in the development of persistent wheezing in children. The protective effect of the GST-P1 Ile(105) genotype may be overwhelmed by multiple environmental exposures that converge on oxidative stress pathways.

Moldy environments and toxic pneumonitis

Exposure to organic dusts might cause an acute reaction with influenza like symptoms (toxic pneumonitis). Although it is well known that endotoxin, which is often present in organic dusts, may cause this reaction, there is no information about fungal cell wall agents as causative agents. The capacity of different fungal cell wall agents to induce an acute inflammation was evaluated in animal inhalation experiments. Guinea pigs were exposed to an aerosol of endotoxin, molds, and different fungal cell wall agents (FCWA) in a continuous flow exposure chamber, and the number of free lung cells was determined 24 h thereafter. Endotoxin caused a dose-dependent increase in the number of neutrophils and macrophages. None of the other agents tested caused a neutrophil response. The results suggest that toxic pneumonitis in environments with organic dusts is caused by the presence of inhaled endotoxin. Although no effect from FCWA was found, it is well known that this inhalation under chronic conditions will cause lung disease, particularly granulomatous pneumonitis.

Stachybotrys chartarum, trichothecene mycotoxins, and damp building-related illness: new insights into a public health enigma

Damp building-related illnesses (DBRI) 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 is 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 DBRI 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, coexposures 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.

Effects of co-culture of amoebae with indoor microbes on their cytotoxic and proinflammatory potential

Free-living amoebae are ubiquitous environmental protozoa found in both natural and man-made environments, including moisture-damaged buildings. Furthermore, the interaction between amoebae and bacteria has been shown to enhance the virulence and pathogenicity of some bacteria. While the inhabitants of moisture damaged buildings are known to be at risk of suffering adverse health effects, the exact causative agents and mechanisms are still obscure. To examine the possible role of amoebae in the health effects associated with moisture damages, the effects of amoebae on the cytotoxicity and proinflammatory potential of nonpathogenic microbes common in moisture-damaged buildings were investigated. First, two bacterial and three fungal strains were cultured both individually and in coculture with Acanthamoeba polyphaga. Then, mouse RAW264.7 macrophages were exposed to the cocultures as well as the individually grown bacteria, fungi, and amoebae. Finally, cell viability and production of proinflammatory mediators, i.e., nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin 6 (IL-6), were measured in macrophages after the exposure. The results revealed that cocultivation with amoebae increased the cytotoxicity of the bacterium Streptomyces californicus and the fungus Penicillium spinulosum. Moreover, the macrophages produced up to 10 times higher concentrations of NO after the exposure to these cocultures than after the exposure to individually grown microbes. Finally, the production of the cytokines was up to two orders of magnitude higher (IL-6) and up to four times higher (TNF-alpha) after exposure to the cocultures when compared to individually grown microbes. We conclude that amoebae are able to potentiate the cytotoxicity and proinflammatory properties of certain microbes associated with moisture damages.

Dose and time dependency of inflammatory responses in the mouse lung to urban air coarse, fine, and ultrafine particles from six European cities

We investigated the dose and time dependency of inflammatory and cytotoxic responses to size-segregated urban air particulate samples in the mouse lung. Coarse (PM10-2.5), fine (PM2.5-0.2), and ultrafine (PM0.2) particles were collected in six European cities (Duisburg, Prague, Amsterdam, Helsinki, Barcelona, Athens) in selected seasons using a modified Harvard high-volume cascade impactor. Healthy C57Bl/6J mice were intratracheally exposed to the particulate samples in a 24-h dose-response study (1, 3, and 10 mg/kg) and in 4-, 12-, and 24-h time course studies (10 mg/kg). After the exposures, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: total cell number, cell differential, total protein, and lactate dehydrogenase (LDH) and cytokine (tumor necrosis alpha [TNF-alpha], interleukin-6 [IL-6], and keratinocyte-derived chemokine [KC]) concentrations. In general, PM10-2.5 samples had higher inflammatory activity than PM2.5-0.2 samples. PM0.2 samples showed negligible inflammatory activity. PM10-2.5 and PM2.5-0.2 samples caused large increases in BALF cytokine concentrations at 4 h, but not at 12 or 24 h, after exposure. The BALF total cell number and total protein concentrations increased significantly at 12 h for both the PM10-2.5 and PM2.5-0.2 samples, but only PM10-2.5 samples produced consistent, significant increases at 24 h after exposure. There was more heterogeneity in BALF cytokine and neutrophil cell number responses to PM2.5-0.2 samples than to PM10-2.5 samples between the sampling campaigns. Thus, particle size, sources, and atmospheric transformation processes affect the inflammatory activity and response duration of urban air particulate matter in the mouse lung.

Volatile organic compounds (VOCs) emitted from materials collected from buildings affected by microorganisms

In this study mould damaged materials, including carpet, concrete, gypsum board, insulation, plastic, sand and wood, from 20 different buildings with moisture problems were collected. To study emissions from these materials both conventional methods for sampling, such as collection on Tenax TA, were used as well as complementary methods for sampling a wider spectrum of compounds, such as more volatile VOCs, amines and aldehydes. Analysis was carried out using gas chromatography and high-performance liquid chromatography. Mass spectrometry was used for identification of compounds. Alcohols and ketones were almost exclusively emitted from the materials after they had been wet for a week. Acids were also emitted in large quantities from wet gypsum board and plastic. No primary or secondary amines could be identified, but two tertiary amines, trimethylamine and triethylamine, were emitted from sand contaminated by Bacillus. The most common moulds found were Penicillium and Aspergillus. A multivariate method (partial least squares, PLS) was used to investigate the emission patterns from the materials. Materials with bacterial growth had a different VOC profile to those with only mould growth.

Effects of microbial cocultivation on inflammatory and cytotoxic potential of spores

Microbial growth on moisture-damaged building materials is commonly associated with adverse health effects in the occupants. In moisture damage situations, the environmental conditions as well as the dominant microbial species will vary, leading to a diversity of microbes and continual changes in the different microbial populations. Currently, very little is known about the effects of microbial cocultures on the potential harmfulness of the microbial population. In this study we have investigated the effects of cocultivation of certain indoor air microbes on the inflammatory and cytotoxic potential of their spores. We grew various microbial combinations made from strains of Streptomyces californicus, Stachybotrys chartarum, Aspergillus versicolor, and Penicillium spinulosum on wetted plasterboard. After 5 or 10 wk of growth, the spores were collected from the plasterboards, mouse RAW264.7 macrophages were exposed to the spores, and after 24 h the induced inflammatory and cytotoxic responses were analyzed. Among all the tested microbes and their combinations, the spores of Str. californicus proved to be the most potent inducer of cytotoxicity and inflammatory responses. These results indicate also that microbial coculture may support the growth of certain microbes with high immunotoxic potency such as Str.californicus. Furthermore, coculture containing S. chartarum and A. versicolor caused a synergistic increase in cytotoxicity compared to the sum response induced by the pure cultures, but no effect on inflammatory responses was detected. Generally, spore-induced cytotoxicity and production of inflammatory markers increased during the growth period from 5 to 10 wk, suggesting that the immunotoxic potency of spores increases with time.

The proportions of Streptomyces californicus and Stachybotrys chartarum in simultaneous exposure affect inflammatory responses in mouse RAW264.7 macrophages

Adverse health outcomes associated with moisture-damaged buildings originate from an exposure consisting of complex interactions between various microbial species and other indoor pollutants. The concentrations and proportions of microbial components in such environments can vary greatly with the growth conditions. In this study, we aimed to evaluate the effects of simultaneous exposure with modified proportions of actinobacteria Streptomyces californicus and fungi Stachybotrys chartarum on inflammatory responses (cytokines macrophage inflammatory protein 2 [MIP2], interleukin 6 [IL-6] and tumor necrosis factor a [TNFa]; nitric oxide) and cytotoxicity (MTT-test and DNA content analysis) in mouse RAW264.7 macrophage cell line. Five different proportions of microbial spores were studied (Str. californicus: S. chartarum 10:1; 5:1; 1:1; 1:5; 1:10). RAW264.7 cells were coexposed to the total dose of 3x10(5) spores/ml for 24 h and also both of these microbial spores on their own at the respective doses. At least the 1.5-fold synergistic increase in cytokine production of RAW264.7 macrophages was detected when coexposure contained an equal amount or more fungal spores (S. chartarum) than bacterial spores (Str. californicus) compared to the sum response caused by these microbial spores separately. On the contrary, NO production after coexposure was nearly 40% less than the sum response induced by the microbial spores separately, when coexposure contains 5 times more bacterial than fungal spores. In addition, coexposure slightly changed the cytotoxic potency of the spores. The present results revealed that mutual proportions of fungal and bacterial spores in simultaneous exposure affect the nature of their interactions leading to increased or suppressed production of inflammatory mediators in RAW264.7 macrophages.

Bioaerosols and sick building syndrome: particles, inflammation, and allergy

PURPOSE OF REVIEW

Sick building syndrome is a poorly understood condition that can be vexing to clinicians and public health investigators alike. Concerns about possible causes have recently shifted to bioaerosols, especially indoor mold contamination. Recently, controversy over the health effects of indoor bioaerosols has intensified in the media and in medical forums. Allergists and other clinicians are increasingly being asked to evaluate cases of sick building syndrome attributed to bioaerosol exposure. Although allergy may play a role, it is unlikely to fully explain the nonspecific symptoms of the condition. This review of recent literature will attempt to put into context the roles of allergy and nonallergic mechanisms in sick building syndrome.

RECENT FINDINGS

Epidemiological and toxicological studies have provided further evidence of a possible link between bioaerosol exposure and sick building syndrome, but continue to have methodological limitations. Cross-sectional studies of building occupants have found associations between bioaerosols and symptoms of the condition, but case definitions and exposure assessment remain problematic. Attempts to develop better exposure assessment and biomonitoring methods have made limited progress. Toxicological studies of inhalation of bioaerosols continue to indicate potential toxicity, but at doses that are not comparable to human exposures indoors.

SUMMARY

Epidemiological studies suggest an association between bioaerosols and sick building syndrome, and toxicological studies have provided some evidence supporting biological plausibility. However, the extent to which bioaerosol exposure may explain the nonspecific symptoms of the condition is unclear. Nonspecific inflammatory responses to bioaerosols, modified by psychosocial factors such as stress, may be a promising area for continued research.

Bacterial strains from moldy buildings are highly potent inducers of inflammatory and cytotoxic effects

We aimed to identify inflammatory and cytotoxic potential of individual indoor air bacterial and fungal strains, as well as extracts of indoor air filter samples containing bacteria and fungi. Mouse RAW264.7 macrophages were exposed in vitro to four bacterial strains; Streptomyces californicus, Mycobacterium terrae, Bacillus cereus and Pseudomonas fluorescens, and three fungal strains; Penicillium spinulosum, Aspergillus versicolor and Stachybotrys chartarum. Furthermore, RAW264.7 macrophages were exposed to indoor air filter sample extracts representing 'low' (n = 21) and 'high' (n = 20) exposure to viable fungi or bacteria. Production of nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) as well as cell viability were measured after 24 h exposure. The results show that the bacterial strains induce more profound production of NO, TNF-alpha and IL-6 than the studied fungal strains. They also decrease the viability of mouse macrophages. Similarly, the indoor air filter samples with high concentration of bacteria induced a statistically significant increase in TNF-alpha and IL-6 production as well as a decrease in cell viability. Altogether, these results suggest that indoor air bacterial strains are potent inducers of inflammatory responses and thus possibly related to adverse health effects of the inhabitants.

PRACTICAL IMPLICATIONS

There is abundant documentation of the association between building dampness and mold and adverse health effects on occupants, but the causal agents of the effects are still unclear. In order to reveal these causal links, experimental studies with in vitro and in vivo methods are needed. The present findings shed new light on studies of the microbial constituents of indoor air in moldy buildings responsible for adverse health effects. These results imply that bacteria should also be monitored in cases of suspected microbial contamination of indoor air.

Starch in plasterboard sustains Streptomyces californicus growth and bioactivity of spores

AIMS

The effects of plasterboard composition on Streptomyces californicus growth and bioactivity of spores were studied.

METHODS AND RESULTS

Streptomyces californicus was grown on 13 modified plasterboards under saturated humidity conditions. The total content of fatty acid methyl esters was used for quantifying S. californicus biomass, while the spore-induced cytotoxicity and production of nitric oxide (NO), tumour necrosis factor-alpha, and interleukine-6 (IL-6) in mouse macrophages was used to assess the bioactivity of spores. Removal of starch completely from the plasterboard or only from the core reduced significantly the biomass production and the biological activity of spores in comparison with reference board. The biocide added into the core or on the liner decreased the growth markedly and inhibited the sporulation totally. The biomass production correlated positively with the spore number, cytotoxicity, and production of NO and IL-6.

CONCLUSIONS

Streptomyces californicus grew under nutrient limitation on all studied plasterboards. The starch is the major factor enabling S. californicus to grow and to produce biologically active metabolites on plasterboard.

SIGNIFICANCE AND IMPACT OF THE STUDY

The composition of building material has an impact on microbial growth and bioactivity of spores which may be involved in complex mechanisms leading to respiratory symptoms in the occupants in moisture damaged buildings.

Systemic immunoresponses in mice after repeated exposure of lungs to spores of Streptomyces californicus

Microbial growth in moisture-damaged buildings is associated with respiratory and other symptoms in the occupants. Streptomyces spp. are frequently isolated from such buildings. In the present study, we evaluated the responses of mice after repeated exposure to spores of Streptomyces californicus. Mice were exposed via intratracheal instillation to six doses (at 7-day intervals) of the spores of S. californicus, originally isolated from the indoor air of a moisture-damaged building, at three dose levels (2 x 10(3), 2 x 10(5), and 2 x 10(7) spores). Inflammation and toxicity, including changes in cell populations in the lungs, lymph nodes, and spleen, were evaluated 24 h after the last dosage. The exposure provoked a dose-dependent inflammatory cell response, as detected by the intense recruitment of neutrophils, but the numbers of macrophages and lymphocytes in the airways also increased. The cellular responses corresponded to the dose-dependent increases in inflammation- and cytotoxicity-associated biochemical markers (i.e., levels of albumin, total protein, and lactate dehydrogenase) in bronchoalveolar lavage fluid. The spore exposure increased the number of both activated and nonactivated T lymphocytes. Also, the amounts of CD3(-) CD4(-) and unconventional CD3(-) CD4(+) lymphocytes in the lung tissue were augmented. Interestingly, the spore exposure decreased cells in the spleen. This effect was strongest at the dose of 2 x 10(5) spores. These results indicate that the spores of S. californicus are capable of provoking both immunostimulation in lungs (inflammation) and systemic immunotoxicity, especially in the spleen. The immunotoxic effect resembled that caused by chemotherapeutic agents, originally isolated from Streptomyces spp. Thus, S. californicus must be considered a microbial species with potential to cause systemic adverse health effects in occupants of moisture-damaged buildings.

Production of proinflammatory mediators by indoor air bacteria and fungal spores in mouse and human cell lines

We compared the inflammatory and cytotoxic responses caused by household mold and bacteria in human and mouse cell lines. We studied the fungi Aspergillus versicolor, Penicillium spinulosum, and Stachybotrys chartarum and the bacteria Bacillus cereus, Pseudomonas fluorescens, and Streptomyces californicus for their cytotoxicity and ability to stimulate the production of inflammatory mediators in mouse RAW264.7 and human 28SC macrophage cell lines and in the human A549 lung epithelial cell line in 24-hr exposure to 10(5), 10(6), and 10(7) microbes/mL. We studied time dependency by terminating the exposure to 10(6) microbes/mL after 3, 6, 12, 24, and 48 hr. We analyzed production of the cytokines tumor necrosis factor-alpha and interleukins 6 and 1ss (TNF-alpha, IL-6, IL-1ss, respectively) and measured nitric oxide production using the Griess method, expression of inducible NO-synthase with Western Blot analysis, and cytotoxicity with the MTT-test. All bacteria strongly induced the production of TNF-alpha, IL-6 and, to a lesser extent, the formation of IL-1ss in mouse macrophages. Only the spores of Str. californicus induced the production of NO and IL-6 in both human and mouse cells. In contrast, exposure to fungal strains did not markedly increase the production of NO or any cytokine in the studied cell lines except for Sta. chartarum, which increased IL-6 production somewhat in human lung epithelial cells. These microbes were less cytotoxic to human cells than to mouse cells. On the basis of equivalent numbers of bacteria and spores of fungi added to cell cultures, the overall potency to stimulate the production of proinflammatory mediators decreased in the order Ps. fluorescens > Str. californicus > B. cereus > Sta. chartarum > A. versicolor > P. spinulosum. These data suggest that bacteria in water-damaged buildings should also be considered as causative agents of adverse inflammatory effects.

Inflammatory potential of the spores of Penicillium spinulosum isolated from indoor air of a moisture-damaged building in mouse lungs

Excess moisture and microbial growth have been associated with adverse health effects, especially in the airways, of the inhabitants of moisture-damaged buildings. The spores of Penicillium spp. are commonly present in the indoor air, both in moisture-damaged and in reference buildings, though their numbers seem to be significantly higher in the damaged buildings. To assess the potential of Penicillium spinulosum to evoke harmful respiratory effects, mice were exposed via intratracheal instillation to a single dose of the spores of P. spinulosum, isolated from the indoor air of a moisture-damaged building (1×10(5), 1×10(6), 5×10(6), 1×10(7) or 5×10(7) spores). Inflammation and toxicity in lungs were evaluated 24 h later. The time-course of the effects was investigated with the dose of 5×10(6) spores for 28 days. The fungal spores caused mild transient inflammation. The spore exposure transiently increased proinflammatory cytokine (TNFα and IL-6) levels in bronchoalveolar lavage fluid (BALF) in a dose- and time-dependent manner. The highest concentrations of both cytokines were measured at 6 h after a single dosage. The spore exposure did not cause expression of inducible nitric oxide synthase in lavaged cells. Neutrophils were acutely recruited into airways, but the response leveled off in 3 days. Neither cytotoxicity nor major changes in vascular permeability (i.e. increases in albumin, total protein, lactate dehydrogenase or hemoglobin levels in BALF) were observed in the lungs. Considering the profile and magnitude of the changes and the dose of the spores, we conclude that P. spinulosum has a low potential to cause acute respiratory inflammation, nor does it cause direct cytotoxicity.