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At least 217 records · Page 12Linked to original sources
PubMed2005

The accelerating effects of the microorganisms on biodeterioration of stone monuments under air pollution and continental-cold climatic conditions in Erzurum, Turkey.

The aim of this research was to determine the accelerating effects of microorganisms on the biodeterioration of stone under air pollution and continental-cold climatic region in Erzurum, Turkey. Studies have been carried out on specimens of the Rustempasa Bazaar, the Lalapasa Mosque, the Erzurum Castle Mosque, the Double Minarets-Madrasah, the Great Mosque and the Haji Mehmet Fountain aged from 441 to 823 years old. The results showed that vegetative and reproductive (generative) forms of the microorganisms could develop during the winter months when the night time average temperature was even -25 degrees C. Also the reproductive forms had developed and the whole stone surface was covered with a biofilm caused by the microorganisms. Silicon, aluminum, calcium, potassium, titanium, magnesium, zinc, sulfur, iron, sodium, and niobium were found in the stones of the historical buildings with varying amounts through the SEM-EDS analysis. Some of these elements could be used as an energy resource for the microorganisms together with the air pollutants such as sulfur dioxide, nitrogen oxides and particles on the stone surfaces. Of 21 isolates, 15 species from 6 bacterium genera and 5 species from 5 fungi genera plus 1 fungi genera were identified on the deteriorated stone surfaces even during the coldest months by microbial identification system (MIS) and these findings were tested by SEM investigations.

Actinobacteria↗
PubMed2003

Flow cytometry and conventional enumeration of microorganisms in ships' ballast water and marine samples.

Conventional methods for bacteriological testing of water quality take long periods of time to complete. This makes them inappropriate for a shipping industry that is attempting to comply with the International Maritime Organization's anticipated regulations for ballast water discharge. Flow cytometry for the analysis of marine and ship's ballast water is a comparatively fast and accurate method. Compared to a 5% standard error for flow cytometry analysis the standard methods of culturing and epifluorescence analysis have errors of 2-58% and 10-30%, respectively. Also, unlike culturing methods, flow cytometry is capable of detecting both non-viable and viable but non-culturable microorganisms which can still pose health risks. The great variability in both cell concentrations and microbial content for the samples tested is an indication of the difficulties facing microbial monitoring programmes. The concentration of microorganisms in the ballast tank was generally lower than in local seawater. The proportion of aerobic, microaerophilic, and facultative anaerobic microorganisms present appeared to be influenced by conditions in the ballast tank. The gradual creation of anaerobic conditions in a ballast tank could lead to the accumulation of facultative anaerobic microorganisms, which might represent a potential source of pathogenic species.

DNA, Bacterial↗
PubMed2001

Correlation of gas chromatographic properties of chlorobenzenes and polychlorinated biphenyls with the occurrence of reductive dechlorination by untamed microorganisms.

To understand the dechlorination ability of chlorobenzenes (CBs) and polychlorinated biphenyls (PCBs) by untamed microorganisms under anaerobic condition and to correlate gas chromatographic properties with the occurrence of reductive dechlorination, introduction of CBs and PCBs in the culture medium inoculated with microorganisms from sludge and sediment, respectively, were performed. Three kinds of culture media preparing from sludge, river water and a synthetic medium were used in the experiments. HCB was degraded to 1,3,5-trichlorobenzene (1,3,5-TCB) and 1,3-dichlorobenzene (1,3-DCB) in both sludge medium and synthetic medium with inoculated microorganisms. Three PCB congeners including 2,3,4-, 3,4,5- and 2,3,4,5-CBp (chlorinated biphenyl) were not found to be dechlorinated in the river water medium with inoculation culture but to be dechlorinated in the synthetic medium. MNDO methodology was used to compute theoretical dechlorination reaction heats and GC-ECD techniques were used to estimate chromatographic data of CB and PCB congeners. Both CB and PCB congeners showed that dechlorination by untamed microorganisms under anaerobic mixed cultures were more likely to occur when larger amounts of energy were released and greater deltaln RRT value between the parent congener and the daughter product was observed. Deltaln RRT provided a more precise information on the singularity of PCBs ortho-dechlorination in an aspect of thermodynamic favorable rule.

Bacteria, Anaerobic↗
PubMed2000

Relationship between electron donor and microorganism on the dechlorination of carbon tetrachloride by an anaerobic enrichment culture.

An investigation involving the supplement of different concentrations of substrates and microorganisms was carried out under anaerobic condition to assess the feasibility of bioremediation of carbon tetrachloride (CCl4) with the amendment of low concentrations of auxiliary substrate and microorganisms. The concentrations of substrate and microorganisms ranged from 10 to 100 mg/l and from 3.7 x 10(4) to 3.7 x 10(6) cell/ml, respectively. The biotransformation rate of CCl4 increased progressively with the increase in the concentrations of the substrate and microorganisms. In the low biomass-amended system (3.7 x 10(4) cells/ml), 28-71% and 57-96% of CCl4 removals were exhibited when 10-100 mg/l of acetate or glucose was supplemented, respectively, whereas nearly complete degradation of CCl4 was observed in the heavily inoculated systems (3.7 x 10(6) cells/ml). An addition of electron donor in the low microbial activity batches enhanced greater efficiency in dechlorination than in the high microbial activity batches. The second-order rate constants ranged from 0.0059 to 0.0092 l/mg/day in high biomass input system, while a two- to four-fold increase in rate constant was obtained in the low microbial activity system. This study indicates that biomass was the more important environmental parameter than substrate affecting the fate of CCl4. The addition of auxiliary substrates was effective only in low biomass-amended batches (0.56 mg-VSS/l) and diminished inversely with the increase of microbial concentration.

Acetates↗
PubMed1997

Marine microorganisms as a source of new natural products.

Over the past decade, marine microorganisms have become recognized as an important and untapped resource for novel bioactive compounds. The oceans cover greater than 70% of the earth's surface and, taking this into account by volume, represent better than 95% of the biosphere. Given this fact, the oceans present themselves as an unexplored area of opportunity for the discovery of pharmacologically active compounds. In this review, data have been presented to illustrate the diversity of microorganisms living in the sea and the plethora of chemical compounds that have been discovered from them. However, it is important to pursue basic research on the marine environment in order to permit the continued isolation of unique microorganisms. There is still limited knowledge of the physiological requirements of most marine microorganisms, and a greater understanding of their conditions for growth will offer new insights into the complex world of marine microbiology. Clearly, a greater investment in the development of marine biotechnology will produce novel compounds that may contribute significantly toward drug development over the next decade.

Animals↗
PubMed2001

Effectiveness of immersion treatments with acids, trisodium phosphate, and herb decoctions in reducing populations of Yarrowia lipolytica and naturally occurring aerobic microorganisms on raw chicken.

Yarrowia lipolytica, one of the predominant yeasts in raw poultry, is believed to play a role in spoilage. This study was undertaken to investigate treatments to control the growth of Y. lipolytica on raw chicken stored at refrigeration temperature. Raw chicken wings inoculated with a mixture of five strains of Y. lipolytica isolated from raw poultry were dipped in solutions containing 2, 5, or 8% lactic acid, 2% lactic acid containing 0.2, 0.4, or 0.8% potassium sorbate or sodium benzoate, and 4, 8, or 12% trisodium phosphate solution. Populations of the yeast and total aerobic microorganisms were determined before and after treatment. Immersion of wings in 2% lactic acid (with or without 0.2% potassium sorbate or sodium benzoate) or 4% trisodium phosphate caused a significant (alpha = 0.05) reduction in numbers of Y. lipolytica and aerobic microorganisms. Treatment with 2% lactic acid containing 0.4 or 0.8% preservative did not result in additional significant reductions. Treatment of chicken wings with 2% lactic acid or 8% trisodium phosphate significantly reduced numbers of Y. lipolytica by 1.47 and 0.65 log10 cfu/g, respectively, and aerobic microorganisms by 2.60 and 1.21 log10 cfu/g, respectively, compared to controls. Growth of Y. lipolytica on wings stored at 5 degrees C for up to 9 days, however, was not affected by these treatments. Significant reductions in the population of Y. lipolytica occurred when the yeast was inoculated into 100% basil, marjoram, sage, and thyme decoctions, but not in 100% oregano or rosemary decoctions, held at 5 degrees C for 24 h. Treatment of chicken wings with 100% sage or thyme decoctions significantly reduced populations of Y. lipolytica but did not control its growth during storage at 5 degrees C for up to 9 days. The small, temporary decreases in numbers of Y. lipolytica and aerobic microorganisms resulting from immersion treatment of chicken wings with sage and thyme decoctions render these treatments of questionable value as preservation interventions.

Animals↗
PubMed1999

Surface characterization and on-line activity measurements of microorganisms by capillary zone electrophoresis.

Capillary zone electrophoresis (CZE) was applied to the electrophoretic characterization for microorganisms. The electrophoretic peaks detected using light scattering phenomena were characteristic of the microorganisms used. The electrophoretic mobility (mu) evaluated by CZE was in good agreement with that obtained by classical electrophoresis of microorganisms. The migration time was reproducible and depended on the ionic strength (I). Analysis of the mu vs. I relationship provided information regarding the charge density and the hardness of the microbial cell surface. The redox enzymatic activity of microorganisms was also evaluated by CZE using a running buffer containing a corresponding substrate and an appropriate exogenous electron acceptor. A decrease in the concentration of the electron acceptor due to microbial activity can be simultaneously monitored during the electrophoretic process without significant modification of the CZE instrument. Effects of some chemical treatments of microbial cells were also studied using this technique.

Bacteria↗
PubMed2000

Ultrasonication of pyrogenic microorganisms improves the detection of pyrogens in the Mono Mac 6 assay.

The monocytic cell line Mono Mac 6 is sensitive to pyrogens. When exposed to pyrogens secretion of interleukin-6 is induced. However, some eukaryotic pyrogenic microorganisms are not detectable. The aim of this study is to introduce a pretreatment of samples to expand the detection range of the assay. The interleukin-6 inducing capacity of a broad spectrum of UV-killed and ultrasonicated microorganisms is examined in Mono Mac 6 cells. The interleukin-6 secretion is determined in a sandwich immunoassay (DELFIA). The Mono Mac 6 assay is able to detect UV-killed Bacillus subtilis, Staphylococcus aureus and Salmonella typhimurium, but neither Candida albicans nor Aspergillus niger. After ultrasonication of the microorganisms it is possible to detect C. albicans and A. niger. The interleukin-6 inducing ability of the examined microorganisms is in no case reduced after ultrasonic treatment. However, ultrasonication of S. aureus results in a 100-fold increase in the interleukin-6 response. Even after ultrasonication Streptococcus faecalis can not be detected. Ultrasonication is an easy and simple method for expanding the detection range in the Mono Mac 6 assay.

Candida albicans↗
PubMed1999

Microorganism identification by mass spectrometry and protein database searches.

A method for rapid identification of microorganisms is presented, which exploits the wealth of information contained in prokaryotic genome and protein sequence databases. The method is based on determining the masses of a set of ions by MALDI TOF mass spectrometry of intact or treated cells. Subsequent correlation of each ion in the set to a protein, along with the organismic source of the protein, is performed by searching an Internet-accessible protein database. Convoluting the lists for all ions and ranking the organisms corresponding to matched ions results in the identification of the microorganism. The method has been successfully demonstrated on B. subtilis and E. coli, two organisms with completely sequenced genomes. The method has been also tested for identification from mass spectra of mixtures of microorganisms, from spectra of an organism at different growth stages, and from spectra originating at other laboratories. Experimental factors such as MALDI matrix preparation, spectral reproducibility, contaminants, mass range, and measurement accuracy on the database search procedure are addressed too. The proposed method has several advantages over other MS methods for microorganism identification.

Bacillus subtilis↗
PubMed2006

Microorganisms pumping iron: anaerobic microbial iron oxidation and reduction.

Iron (Fe) has long been a recognized physiological requirement for life, yet for many microorganisms that persist in water, soils and sediments, its role extends well beyond that of a nutritional necessity. Fe(II) can function as an electron source for iron-oxidizing microorganisms under both oxic and anoxic conditions and Fe(III) can function as a terminal electron acceptor under anoxic conditions for iron-reducing microorganisms. Given that iron is the fourth most abundant element in the Earth's crust, iron redox reactions have the potential to support substantial microbial populations in soil and sedimentary environments. As such, biological iron apportionment has been described as one of the most ancient forms of microbial metabolism on Earth, and as a conceivable extraterrestrial metabolism on other iron-mineral-rich planets such as Mars. Furthermore, the metabolic versatility of the microorganisms involved in these reactions has resulted in the development of biotechnological applications to remediate contaminated environments and harvest energy.

Bacteria, Anaerobic↗
PubMed2002

Diversity of halophilic microorganisms: environments, phylogeny, physiology, and applications.

The phylogenetic diversity of microorganisms living at high salt concentrations is surprising. Halophiles are found in each of the three domains: Archaea, Bacteria, and Eucarya. The metabolic diversity of halophiles is great as well: they include oxygenic and anoxygenic phototrophs, aerobic heterotrophs, fermenters, denitrifiers, sulfate reducers, and methanogens. The diversity of metabolic types encountered decreases with salinity. The upper salinity limit at which each dissimilatory process takes place is correlated with the amount of energy generated and the energetic cost of osmotic adaptation. Our understanding of the biodiversity in salt-saturated environments has increased greatly in recent years. Using a combination of culture techniques, molecular biological methods, and chemotaxonomic studies, we have obtained information on the nature of the halophilic Archaea as well as the halophilic Bacteria that inhabit saltern crystallizer ponds. Several halophilic microorganisms are being exploited in biotechnology. In some cases, such as the production of ectoine, the product is directly related to the halophilic behavior of the producing microorganism. In other cases, such as the extraction of beta-carotene from Dunaliella or the potential use of Haloferax species for the production of poly-beta-hydroxyalkanoate or extracellular polysaccharides, similar products can be obtained from non-halophiles, but halophilic microorganisms may present advantages over the use of non-halophilic counterparts.

Adaptation, Physiological↗
PubMed2003

Recent increase in antibiotic-resistant microorganisms in patients with spontaneous bacterial peritonitis adversely affects the clinical outcome in Korea.

BACKGROUND AND AIM: Recently, antibiotic-resistant microorganisms have been increasingly noted in Korean patients with spontaneous bacterial peritonitis (SBP). The present study investigated the changing pattern of antibiotic resistance and its effects on the clinical outcome in treating SBP. METHODS: The present study retrospectively analyzed 87 episodes of SBP in 1995, 222 in 1998, and 271 in 1999. The isolated microorganisms and their antibiotic susceptibility were compared, and prognostic factors for survival were analyzed. RESULTS: Microorganisms were isolated in 41% of total episodes. The three most frequently isolated organisms were Escherichia coli (48%), Klebsiella pneumoniae (15%), and Aeromonas (8%). Strains that were resistant to cefotaxime in Gram-negative bacilli significantly increased from 7% in 1995 to 28% in 1999, and those to ciprofloxacin increased from 10% to 32%. Treatment failure also increased from 6% to 23%. Combined hepatocellular carcinoma and SBP caused by extended-spectrum beta-lactamase-producing strains were two independent prognostic factors for survival. CONCLUSION: Considering the increase in antibiotic-resistant microorganisms related to SBP, measures to prevent the in-hospital spread of resistant strains and the indiscriminate use of antibiotics should be instituted more stringently.

4-Quinolones↗
PubMed2001

Identification of a microorganism that links its growth to the reductive dechlorination of 2,3,5,6-chlorobiphenyl.

Anaerobic bacteria reductively dechlorinate polychlorinated biphenyls (PCBs) in aquatic sediments, but these microorganisms remain uncultured and, until now, unidentified. Through denaturing gradient gel electrophoresis (DGGE) of 16S rDNA from a highly enriched ortho-PCB dechlorinating culture, the growth of a single microorganism was shown to be dependent upon the presence and dechlorination of 2,3,5,6-tetrachlorobiphenyl. This is the first identification of a microorganism that catalyses the reductive dechlorination of a PCB. The organism, bacterium o-17, has high sequence similarity with the green non-sulphur bacteria and with a group that includes Dehalococcoides ethenogenes. Bacterium o-17 required acetate for dechlorination and growth. H2:CO2 (80:20 at 101 kPa) did not support dechlorination or growth of the dechlorinator. Archaeal 16S rDNA was not detected in actively dechlorinating bromoethanesulphonate-treated non-methanogenic cultures, which indicated that methanogenic Archaea were not required for dechlorination. The consistent association with dechlorinating activity combined with high similarity to other known dechlorinating microorganisms indicates that bacterium o-17 catalyses the reductive ortho-dechlorination of 2,3,5,6-tetrachlorobiphenyl.

Acetates↗
PubMed2002

Reduction of humic substances by halorespiring, sulphate-reducing and methanogenic microorganisms.

Physiologically distinct anaerobic microorganisms were explored for their ability to oxidize different substrates with humic acids or the humic analogue, anthraquinone-2,6-disulphonate (AQDS), as a terminal electron acceptor. Most of the microorganisms evaluated including, for example, the halorespiring bacterium, Desulfitobacterium PCE1, the sulphate-reducing bacterium, Desulfovibrio G11 and the methanogenic archaeon, Methanospirillum hungatei JF1, could oxidize hydrogen linked to the reduction of humic acids or AQDS. Desulfitobacterium dehalogenans and Desulfitobacterium PCE1 could also convert lactate to acetate linked to the reduction of humic substances. Humus served as a terminal electron acceptor supporting growth of Desulfitobacterium species, which may explain the recovery of these microorganisms from organic rich environments in which the presence of chlorinated pollutants or sulphite is not expected. The results suggest that the ubiquity of humus reduction found in many different environments may be as a result of the increasing number of anaerobic microorganisms, which are known to be able to reduce humic substances.

Anthraquinones↗
PubMed2002

A fluorimetric method for the estimation of G+C mol% content in microorganisms by thermal denaturation temperature.

G+C mol% content in microorganisms is one of the recommended characteristics for the standard description of bacterial species. In this study we present a novel fluorimetric method to estimate the G+C mol% content in microorganisms. Double-stranded DNA was specifically stained with SYBR Green I, and its thermal denaturalization was followed by measuring a decrease in fluorescence using a real-time PCR thermocycler. Unlike most previous determinations of G+C mol%, in this study only DNA from microorganisms with an available completely sequenced genome were used to prepare the calibration curves. Calibration curves showed a linear relationship between G+C mol% content and melting temperature and they were performed both in the absence and presence of 30% formamide. This protocol proves to be a rapid and inexpensive method to estimate DNA base ratios of novel microorganisms.

Base Composition↗
PubMed2006

Petroleum pollutant degradation by surface water microorganisms.

BACKGROUND, AIMS AND SCOPE: It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light. METHODS: Microorganisms were analyzed in a surface water sample from a canal (Pancevo, Serbia), into which wastewater from an oil refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant species: Phormidium foveolarum--filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform. In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were analyzed by GC-MS. RESULTS AND DISCUSSION: Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic type petroleum, such a trend has not been observed. The most intensive degradation of n-alkanes and isoprenoid aliphatic alkanes (in paraffinic oil) and isoprenoids (in naphthenic oil) was observed using the inorganic medium Kp in the light; the microbial conversion is somewhat lower with Kp in the dark; with organic medium Bh in the light the degradation is of low intensity; with the same medium in the dark the degradation is hardly to be seen. Steranes and triterpanes were not affected by microbial degradation under the conditions used in our experiments. Obviously, the petroleum biodegradation was restricted to the acyclic aliphatics (n-alkanes and isoprenoids). CONCLUSION: Phormidium foveolarum (filamentous Cyanobacteria--blue-green algae) and Achanthes minutissima (diatoms, algae), microbial cultures isolated as dominant algae from a surface water in a wastewater canal of an oil refinery and a nitrogen plant, have degradable effects dominantly involving petroleum hydocarbons. Petroleum microbiological degradation is more intensive when inorganic medium (in the light) is applied. Having in mind that the inorganic pollutants have been released into the canal as well, this medium reflects more the natural environmental conditions. Polycyclic alkanes of sterane and triterpane type, in spite of the fact that these compounds could be degraded, have remained unchanged regarding abundance and distribution. Since this is the case even for naphthenic type petroleum (which is depleted in n-alkanes), it can be concluded that the biodegradation of petroleum type pollutants, under natural conditions, will be restrained to the n-alkane and isoprenoid degradation. RECOMMENDATION AND OUTLOOK: Performed experiments and simulations of petroleum microbiological degradation may serve for the prediction of the fate of petroleum type pollutants, as well as for definition of conditions for bioremediation of some environmental segments.

Biodegradation, Environmental↗
PubMed2005

Respiratory protection provided by N95 filtering facepiece respirators against airborne dust and microorganisms in agricultural farms.

A new system was used to determine the workplace protection factors (WPF) for dust and bioaerosols in agricultural environments. The field study was performed with a subject wearing an N95 filtering facepiece respirator while performing animal feeding, grain harvesting and unloading, and routine investigation of facilities. As expected, the geometric means (GM) of the WPFs increased with increasing particle size ranging from 21 for 0.7-1 microm particles to 270 for 5-10 microm particles (p < 0.001). The WPF for total culturable fungi (GM = 35) was significantly greater than for total culturable bacteria (GM = 9) (p = 0.01). Among the different microorganism groups, the WPFs of Cladosporium, culturable fungi, and total fungi were significantly correlated with the WPFs of particles of the same sizes. As compared with the WPFs for dust particles, the WPFs for bioaerosols were found more frequently below 10, which is a recommended assigned protection factor (APF) for N95 filtering facepiece respirators. More than 50% of the WPFs for microorganisms (mean aerodynamic diameter < 5 microm) were less than the proposed APF of 10. Even lower WPFs were calculated after correcting for dead space and lung deposition. Thus, the APF of 10 for N95 filtering facepiece respirators seems inadequate against microorganisms (mean aerodynamic size < 5 microm). These results provide useful pilot data to establish guidelines for respiratory protection against airborne dust and microorganisms on agricultural farms. The method is a promising tool for further epidemiological and intervention studies in agricultural and other similar occupational and nonoccupational environments.

Agriculture↗
PubMed2006

Personal exposure to airborne dust and microorganisms in agricultural environments.

Airborne dust and microorganisms are associated with respiratory diseases and increased mortality and morbidity. Farmers are at high risk of exposure to both of these hazards. Very limited information, however, is available on the combined exposures to both hazards on different types of farms. Moreover, most of the previous studies have measured the mass concentration of particles ignoring the particle size. In this study, farmers' exposure to airborne dust and microorganisms was studied using our newly developed personal sampling system. Particle number concentration and size distribution were measured with an optical particle counter. Simultaneously, particles were collected on a filter and analyzed for microorganisms. The field measurements were conducted in animal confinements (swine, poultry, and dairy) and during grain harvesting (corn and soybean). The results show the following average concentrations on the workers' breathing zone: 1.7 x 10(6) to 2.9 x 10(7) particles/m(3) for total dust, 0.9 x 10(3) to 3.9 x 10(4) spores/m(3) for total fungal spores, 0.3 x 10(3) to 3.6 x 10(4)CFU/m(3) for culturable fungal spores, 0.3 x 10(4) to 3.3 x 10(8) CFU/m(3) for culturable bacteria, and limit of detection (LOD) to 2.8 x 10(3) CFU/m(3) for culturable actinomycetes in animal confinements. The respective concentrations were 4.4 x 10(6) to 5.8 x 10(7) particles/m(3), 3.4 x 10(4) to 6.1 x 10(6) spores/m(3), 8.2 x 10(4) to 7.4 x 10(6) CFU/m(3), 0.4 x 10(5) to 1.4 x 10(6) CFU/m(3), and LOD to 2.6 x 10(4) CFU/m(3) during grain harvesting. The highest contribution of large particles (3-10 microm) in total particles was found during grain harvesting, whereas the size distribution was dominated by smaller particles (< 3 microm) in animal confinements. High fraction (up to 37%) of particles between 2-10 microm was found to be fungal spores. The results indicate that an increase in the concentration of large dust particles (2-10 microm) during grain harvesting was partially attributed to the increase in the concentration of the fungal spores. Overall, the combined exposure to airborne dust and microorganisms was found to be more severe during harvesting than in animal confinements.

Aerosols↗