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1.
Exposure to Aspergillus fumigatus is linked with respiratory diseases such as asthma, invasive aspergillosis, hypersensitivity pneumonitis, and allergic bronchopulmonary
aspergillosis. Molecular methods using quantitative PCR (qPCR) offer advantages over culture and optical methods for estimating
human exposures to microbiological agents such as fungi. We describe an assay that uses lyticase to digest A. fumigatus conidia followed by TaqMan™ qPCR to quantify released DNA. This method will allow analysis of airborne A. fumigatus samples collected over extended time periods and provide a more representative assessment of chronic exposure. The method
was optimized for environmental samples and incorporates: single tube sample preparation to reduce sample loss, maintain simplicity,
and avoid contamination; hot start amplification to reduce non-specific primer/probe annealing; and uracil-N-glycosylase to prevent carryover contamination. An A. fumigatus internal standard was developed and used to detect PCR inhibitors potentially found in air samples. The assay detected fewer
than 10 A. fumigatus conidia per qPCR reaction and quantified conidia over a 4−log10 range with high linearity (R
2 > 0.99) and low variability among replicate standards (CV=2.0%) in less than 4 h. The sensitivity and linearity of qPCR for
conidia deposited on filters was equivalent to conidia calibration standards. A. fumigatus DNA from 8 isolates was consistently quantified using this method, while non-specific DNA from 14 common environmental fungi,
including 6 other Aspergillus species, was not detected. This method provides a means of analyzing long term air samples collected on filters which may
enable investigators to correlate airborne environmental A. fumigatus conidia concentrations with adverse health effects. 相似文献
2.
The large, outdoor Islip Yard Waste Composting Facility on Long Island, New York was investigated as a source of airborne
fungus spores. The Burkard-Hirst volumetric spore trap was used for the first extensive sampling of small mold spores for
this application. Samplers were operated continuously from 21 August to 30 November 1992 in the facility and in a suburban
community about 540 m from the facility. A control site approximately 10 000 m from the facility was also sampled to establish
background levels of fungus spores. The facility site had higher average readings ofAspergillus fumigatus spores than did the community and both were higher than the control.A. fumigatus was the only fungus among 30 categories tracked that differed significantly between the facility and control sites. It was
also isolated repeatedly from the compost. Higher average levels ofA. fumigatus were measured in the community when winds blew from the facility, and also during times when the compost was moved or mixed
at the facility. No correlation was found between wind direction or work times andA. fumigatus conidia at the control site. The study shows that this compost facility can produce a measurable increase in the number of
airborneA. fumigatus conidia both at the edge of the facility and at 540 m downwind. It also demonstrates that the Burkard spore trap can be used
for monitoring small, airborne mold spores, but it is a difficult and labor intensive task. 相似文献
3.
Taisa Magnani Frederico Marianetti Soriani Vicente de Paulo Martins Anna Carolina de Freitas Policarpo Carlos Artério Sorgi Lúcia Helena Faccioli Carlos Curti Sérgio Akira Uyemura 《Journal of bioenergetics and biomembranes》2008,40(6):631-636
We previously demonstrated that conidia from Aspergillus fumigatus incubated with menadione and paraquat increases activity and expression of cyanide-insensitive alternative oxidase (AOX).
Here, we employed the RNA silencing technique in A. fumigatus using the vector pALB1/aoxAf in order to down-regulate the aox gene. Positive transformants for aox gene silencing of A. fumigatus were more susceptible both to an imposed in vitro oxidative stress condition and to macrophages killing, suggesting that AOX is required for the A. fumigatus pathogenicity, mainly for the survival of the fungus conidia during host infection and resistance to reactive oxygen species
generated by macrophages. 相似文献
4.
Françoise Botterel Karine Gross Oumaïma Ibrahim-Granet Khaled Khoufache Virginie Escabasse André Coste Catherine Cordonnier Estelle Escudier Stéphane Bretagne 《BMC microbiology》2008,8(1):97
Background
Invasive aspergillosis, which is mainly caused by the fungus Aspergillus fumigatus, is an increasing problem in immunocompromised patients. Infection occurs by inhalation of airborne conidia, which are first encountered by airway epithelial cells. Internalization of these conidia into the epithelial cells could serve as a portal of entry for this pathogenic fungus. 相似文献5.
Ergot alkaloids are mycotoxins that interact with several monoamine receptors, negatively affecting cardiovascular, nervous, reproductive, and immune systems of exposed humans and animals. Aspergillus fumigatus, a common airborne fungus and opportunistic human pathogen, can produce ergot alkaloids in broth culture. The objectives of this study were to determine if A. fumigatus accumulates ergot alkaloids in a respirable form in or on its conidia, to quantify ergot alkaloids associated with conidia produced on several different substrates, and to measure relevant physical properties of the conidia. We found at least four ergot alkaloids, fumigaclavine C, festuclavine, fumigaclavine A, and fumigaclavine B (in order of abundance), associated with conidia of A. fumigatus. Under environmentally relevant conditions, the total mass of ergot alkaloids often constituted >1% of the mass of the conidium. Ergot alkaloids were extracted from conidia produced on all media tested, and the greatest quantities were observed when the fungus was cultured on latex paint or cultured maize seedlings. The values for physical properties of conidia likely to affect their respirability (i.e., diameter, mass, and specific gravity) were significantly lower for A. fumigatus than for Aspergillus nidulans, Aspergillus niger, and Stachybotrys chartarum. The demonstration of relatively high concentrations of ergot alkaloids associated with conidia of A. fumigatus presents opportunities for investigations of potential contributions of the toxins to adverse health effects associated with the fungus and to aspects of the biology of the fungus that contribute to its success. 相似文献
6.
Susceptibility of Larvae of Galleria mellonella to Infection by Aspergillus fumigatus is Dependent upon Stage of Conidial Germination 总被引:1,自引:0,他引:1
The ability of conidia of the human pathogenic fungus Aspergillus fumigatus to kill larvae of the insect Galleria mellonella was investigated. Conidia at different stages of the germination process displayed variations in their virulence as measured
using the Galleria infection model. Non-germinating (‘resting’) conidia were avirulent except when an inoculation density of 1 × 107 conidia per insect was used. Conidia that had been induced to commence the germination process by pre-culturing in growth
medium for 3 h were capable of killing larvae at densities of 1 × 106 and 1 × 107 per insect. An inoculation density of 1 × 105 conidia per insect remained avirulent. Conidia in the outgrowth phase of germination (characterised as the formation of a
germ tube) were the most virulent and were capable of killing 100% of larvae after 5 or 24 h when 1 × 107 or 1 × 106 conidia, that had been allowed to germinate for 24 h, were used. Examination of the response of insect haemocytes to conidia
at different stages of the germination process established that haemocytes could engulf non-germinating conidia and those
in the early stages of the germination process but that conidia, which had reached the outgrowth stages of germination were
not phagocytosed. The results presented here indicate that haemocytes of G. mellonella are capable of phagocytosing A. fumigatus conidia less than 3.0 μm in diameter but that conidia greater than this are too large to be engulfed. The virulence of A. fumigatus in G. mellonella larvae can be ascertained within 60–90 h if infection densities of 1 × 106 or 1 × 107 activated conidia (pre-incubated for 2–3 h) per insect are employed. 相似文献
7.
F. Féménia D. Huet S. Lair-Fulleringer M. C. Wagner J. Sarfati L. Shingarova J. Guillot P. Boireau R. Chermette N. Berkova 《Mycopathologia》2009,167(5):249-262
Aspergillus species can cause mycoses in human and animals. Previously, we demonstrated that A. fumigatus conidia from a human isolate inhibited apoptosis in human pneumocytes and bronchial epithelial cells. In the current study,
we studied the effects of A. fumigatus conidia non-human origin and A. flavus,
A. nidulans, A. niger and A. oryzae conidia on human cells apoptosis. Human pneumocytes or bronchial epithelial cells were simultaneously exposed to apoptotic
inductors and aspergilli conidia. The cell cultures were analyzed by flow cytometry, immunoblotting, and examination of nuclear
morphology. Similar to A. fumigatus conidia, A. flavus conidia inhibited cellular apoptosis while A. nidulans, A. niger and A. oryzae conidia did not affect apoptosis. We further studied the species specificity of conidia: there were no differences in the
inhibition of apoptosis by A. fumigatus conidia from either human or bird isolates. In order to determine whether the inhibition of apoptosis by conidia is limited
to certain strains, the effect on human cell apoptosis of different A. fumigatus human clinical isolates and A. fumigatus of environmental origin was evaluated. All A. fumigatus isolates inhibited apoptosis; an anti-apoptotic factor was released by conidia. For TNF-induced apoptosis, the anti-apoptotic
effect of conidia of all isolates was found to be associated with a reduction of caspase-3 in human cells. The results suggest
that suppression of apoptosis may play a role in reducing the efficacy of host defense mechanisms during infection with Aspergillus species.
F. Féménia and D. Huet made an equal contribution to this work. 相似文献
8.
Bhatti MF Jamal A Petrou MA Cairns TC Bignell EM Coutts RH 《Fungal genetics and biology : FG & B》2011,48(11):1071-1075
Some isolates of the opportunistic human pathogenic fungus Aspergillus fumigatus are known to be infected with mycoviruses. The dsRNA genomes of two of these mycoviruses, which include a chrysovirus and a partitivirus, have been completely sequenced and an RT-PCR assay for the viruses has been developed. Through curing virus-infected A. fumigatus isolates by cycloheximide treatment and transfecting virus-free isolates with purified virus, as checked by RT-PCR, isogenic virus-free and virus-infected lines of the fungus were generated whose phenotypes and growth have been directly compared. Mycovirus infection of A. fumigatus with either the chrysovirus or the partitivirus resulted in significant aberrant phenotypic alterations and attenuation of growth of the fungus but had no effect on susceptibility to common antifungals. Chrysovirus infection of A. fumigatus caused no significant alterations to murine pathogenicity. 相似文献
9.
Effects of extracts of fiberglass insulations on the growth ofAspergillus fumigatus andA. versicolor
Water extracts of thermal and acoustic fiberglass insulations used in the duct work of heating, ventilation and air conditioning (HVAC) systems supported germination of conidia and growth ofAspergillus versicolor (Vuillemin) Tiraboschi 1908–9 andAspergillus fumigatus Fresenius 1863. Urea, formaldehyde and unidentified organics were detected in the extracts. Formaldehyde in concentrations similar to those found in the extracts restricted the growth of both species in enriched media.A. versicolor, the more common species associated with fiberglass insulations, was more resistant to formaldehyde thanA. fumigatus. 相似文献
10.
To accurately quantify airborne Aspergillus fumigatus (A. fumigatus) spores in rabbit houses, the real-time polymerase chain reaction (real-time PCR) and culture-based counting method (CCM)
were employed to determine the airborne A. fumigatus spore concentrations. The results showed that, of the three rabbit houses (A, B, and C), the average concentrations of airborne
A. fumigatus spores determined by real-time PCR were 3.0 × 103, 3.3 × 103, and 1.5 × 103 spores/m3 air, respectively, while those determined by CCM were 2.5 × 102, 2.8 × 102, and 1.1 × 102 colony-forming unit/m3 air (CFU/m3 air), respectively, i.e., the former concentration was 12–14 times higher than the latter one. Therefore, the conventional
CCM underestimated the concentrations of airborne fungal spores, and it is insufficient to determine the microbial aerosol
concentration and evaluate the health risk only using CCM. 相似文献
11.
Environmental samples analyzed by quantitative PCR (qPCR) are subject to interference by inhibitors present in the environment
being sampled. A controlled determination of the effect of inhibitors associated with sampling indoor air and the ability
of internal standard controls to detect inhibition was carried out by filter collection of air samples followed by spiking
of the filters with green fluorescent protein-expressing Aspergillus fumigatus conidia. Microscopic conidial counts were compared with qPCR results and correlated with levels of particulate matter and
viable airborne microorganisms. Our data showed that PCR can be inhibited by masses of particulate matter as low as 50 μg
and that the amount of inhibition was positively correlated with the mass of particulate (r = 0.75) and the number of non-filamentous organisms (r = 0.73). The use of internal standard DNA identified the presence of inhibitors and indicated the need for additional sample
processing or qualification of sample results. 相似文献
12.
Valeria Prigione Guido Lingua Valeria Filipello Marchisio 《Applied microbiology》2004,70(3):1360-1365
Traditional methods for the enumeration of airborne fungi are slow, tedious, and rather imprecise. In this study, the possibility of using flow cytometry (FCM) for the assessment of exposure to the fungus aerosol was evaluated. Epifluorescence microscopy direct counting was adopted as the standard for comparison. Setting up of the method was achieved with pure suspensions of Aspergillus fumigatus and Penicillium brevicompactum conidia at different concentrations, and then analyses were extended to field samples collected by an impinger device. Detection and quantification of airborne fungi by FCM was obtained combining light scatter and propidium iodide red fluorescence parameters. Since inorganic debris are unstainable with propidium iodide, the biotic component could be recognized, whereas the preanalysis of pure conidia suspensions of some species allowed us to select the area corresponding to the expected fungal population. A close agreement between FCM and epifluorescence microscopy counts was found. Moreover, data processing showed that FCM can be considered more precise and reliable at any of the tested concentrations. 相似文献
13.
Stuart M. Levitz David J. DiBenedetto Richard D. Diamond 《Antonie van Leeuwenhoek》1990,58(2):107-114
Both components of the polyamine oxidase (PAO)-polyamine system are known to be present in phagocytes and have thus been postulated to contribute to the antimicrobial activity of these cells. Therefore, the effects of the PAO-polyamine system on three medically important opportunistic fungi were examined. Yeasts of Cryptococcus neoformans, but not Candida albicans blastoconidia or Aspergillus fumigatus conidia, were efficiently killed by the system. Two putative end products of the system, hydrogen peroxide and acrolein, both killed C. neoformans at concentrations attainable with the whole system. However, catalase failed to inhibit activity of the whole system, making hydrogen peroxide an unlikely mediator of killing. Although C. albicans blastoconidia and A. fumigatus conidia were not killed by the PAO-polyamine system, germ tube formation by the former, and hyphal growth by the latter, were markedly inhibited. These data establish that the PAO-polyamine system possesses antifungal activity. 相似文献
14.
Avian aspergillosis is reported in several avian species, with Aspergillus fumigatus as the main aetiological agent. Predisposing factors such as starvation, thermal stress, migratory stress, primary infectious
disease or toxicosis may play a role. Eight cases of disseminated aspergillosis in free ranging seagulls sheltered at C.R.U.M.A.
(Centro Recupero Uccelli Marini e Acquatici, Livorno, Italy) with different clinical histories are presented. The infection
was demonstrated by cultural and histological methods from lesions of all birds, and the presence of airborne A. fumigatus viable elements ranging from 450 to 525 CFU/m3 inside and outside the shelter by means of a surface air sampler (SAS) Super-90 was also assessed. The role of this fungal
species as an opportunistic factor in the captivity of seagulls is considered and some control measures, such as a clean and
stress free environment and the use of antifungal drugs are suggested. 相似文献
15.
The filamentous fungus Aspergillus fumigatus is the most prevalent airborne fungal pathogen causing severe and usually fatal invasive aspergillosis in immunocompromised patients. This fungus produces a large number of small hydrophobic asexual spores called conidia as the primary means of reproduction, cell survival, propagation, and infectivity. The initiation, progression, and completion of asexual development (conidiation) is controlled by various regulators that govern expression of thousands of genes associated with formation of the asexual developmental structure conidiophore, and biogenesis of conidia. In this review, we summarize key regulators that directly or indirectly govern conidiation in this important pathogenic fungus. Better understanding these developmental regulators may provide insights into the improvement in controlling both beneficial and detrimental aspects of various Aspergillus species. 相似文献
16.
Despite the development of new treatments, the mortality due to invasive pulmonary aspergillosis remains above 50%, reaching 95% in certain situations. The battle against Aspergillus fumigatus involves several components of the pulmonary innate immune system: cells, mediators, and natural antifungal molecules involved in the recognition and elimination of the fungus, thereby preventing colonization of the respiratory system.With the 10,000–15,000 l of air we inhale each day, the lungs are constantly exposed to a wide range of microorganisms, such as A. fumigatus. This fungus is ubiquitous in the environment and can release large numbers of spores able, due to their small size, to penetrate the respiratory tract. The spores of A. fumigatus, like any other pathogen, are then confronted with the innate immune system, a constitutive defense system that is permanently active and tightly regulated. The various elements of the pulmonary innate immune system—physical and cellular barriers and soluble mediators—are involved in the recognition and elimination of pathogens, thereby preventing colonization of the respiratory system. Consequently, the presence of spores in immunocompetent hosts is completely innocuous, because these spores are normally eliminated. However, changes in one of the components of the defense system may lead to the development of pulmonary infections. Thus, in immunocompromised individuals, the spores are able to develop and cause pulmonary mycoses. These mycoses, known as aspergillosis, are highly variable, with the range of presentations extending from an allergy-type illness, allergic bronchopulmonary aspergilloses, to a very serious generalized and frequently fatal infection: invasive pulmonary aspergillosis (IPA). 相似文献
17.
18.
Termites, Coptotermes formosanus, reared individually, were highly susceptible to the entomopathogenic fungus, Metarhizium anisopliae, while termites reared in␣groups were highly resistant. When reared in groups, the termites treated with M.␣anisopliae conidia on the body surface were groomed by their nestmates and more than 80% of the conidia were removed from the cuticle
within 3 h. However, there was not a significant reduction in the numbers of conidia on the body surfaces of termites reared
individually. For the termites maintained in groups, conidia were found in foreguts, midguts and hindguts, but very few conidia
were detected in the guts of termites reared individually. Conidia in the alimentary tracts did not germinate, but some of
were alive. As a result, it seems that the removal of foreign bodies, such as fungal conidia, from the␣cuticle is one function
of termite mutual grooming behavior and that conidia removed from the cuticle are eliminated through alimentary tracts. This
study indicates that mutual grooming behavior is very effective in protecting these termites from M.␣anisopliae infection. 相似文献
19.
Naama Lang‐Yona Yishai Levin Karen C. Dannemiller Oded Yarden Jordan Peccia Yinon Rudich 《Global Change Biology》2013,19(8):2381-2388
Increased susceptibility to allergies has been documented in the Western world in recent decades. However, a comprehensive understanding of its causes is not yet available. It is therefore essential to understand trends and mechanisms of allergy‐inducing agents, such as fungal conidia. In this study, we investigated the hypothesis that environmental conditions linked to global atmospheric changes can affect the allergenicity of Aspergillus fumigatus, a common allergenic fungal species in indoor and outdoor environments and in airborne particulate matter. We show that fungi grown under present‐day CO2 levels (392 ppm) exhibit 8.5 and 3.5 fold higher allergenicity compared to fungi grown at preindustrial (280 ppm) and double (560 ppm) CO2 levels, respectively. A corresponding trend is observed in the expression of genes encoding for known allergenic proteins and in the major allergen Asp f1 concentrations, possibly due to physiological changes such as respiration rates and the nitrogen content of the fungus, influenced by the CO2 concentrations. Increased carbon and nitrogen levels in the growth medium also lead to a significant increase in the allergenicity. We propose that climatic changes such as increasing atmospheric CO2 levels and changes in the fungal growth medium may impact the ability of allergenic fungi such as A. fumigatus to induce allergies. 相似文献
20.
Martin Vödisch Daniela Albrecht Franziska Leßing André D. Schmidt Robert Winkler Reinhard Guthke Axel A. Brakhage Olaf Kniemeyer Dr. 《Proteomics》2009,9(5):1407-1415
The filamentous fungus Aspergillus fumigatus has become the most important airborne fungal pathogen causing life‐threatening infections in immunosuppressed patients. We established a 2‐D reference map for A. fumigatus. Using MALDI‐TOF‐MS/MS, we identified 381 spots representing 334 proteins. Proteins involved in cellular metabolism, protein synthesis, transport processes and cell cycle were most abundant. Furthermore, we established a protocol for the isolation of mitochondria of A. fumigatus and developed a mitochondrial proteome reference map. 147 proteins represented by 234 spots were identified. 相似文献