Phylogenetic diversity and vertical distribution of a halobacterial community in the atmosphere of an Asian dust (KOSA) source region, Dunhuang City

Air Quality Atmosphere & Health (Impact Factor: 1.46). 10/2008; 1(2):81-89. DOI: 10.1007/s11869-008-0016-9

ABSTRACT The microbial communities transported by Asian desert dust (KOSA) events have attracted much attention as bioaerosols because
the transported microorganisms are thought to influence the downwind ecosystems in Korea and Japan. We have analyzed bioaerosol
samples collected at 10 and 800m above the ground within the KOSA source area, Dunhuang City, China. The samples were studied
by epifluorescent microscopy, revealing the presence of bacterial cells attached to mineral particles. The microorganisms
in the bioaerosol samples were able to grow in media containing up to 20% NaCl, suggesting that bacteria tolerant to high
salinities remain viable in the atmosphere. Phylogenetic analysis using 16S rDNA sequences revealed that halobacterial communities
in the bioaerosol samples collected at both 10 and 800m above the ground comprised a few bacterial species related to Bacillus pumilus and Staphylococcus spp. The active mixing processes of the boundary layer presumably transports viable halotolerant bacteria into the free atmosphere,
where the long-range atmospheric transport of desert dust is frequently observed.

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    ABSTRACT: This work focuses on the analysis of bioaerosols in the atmosphere at higher altitudes over Noto Peninsula, Japan. We carried out direct sampling via aircraft, separated cultures, and identified present isolates. Atmospheric bioaerosols at higher altitudes were collected using a Cessna 404 aircraft for an hour at an altitude of 3,500 m over the Noto Peninsula. The aircraft-based direct sampling system was devised to improve upon the system of balloon-based sampling. In order to examine pre-existing microorganism contamination on the surface of the aircraft body, bioaerosol sampling was carried out just before takeoff using the same method as atmospheric sampling. Identification was carried out by a homology search for 16S or 18S rDNA isolate sequences in DNA databases (GenBank). Isolate sampling just before takeoff revealed Stretpomyces sp., Micrococcus sp., and Cladosporium sp. One additional strain, Bacillus sp., was isolated from the sample after bioaerosol collection at high altitude. As the microorganism contamination on the aircraft body before takeoff differed from that while in the air, the presence of additional, higher atmosphere-based microorganisms was confirmed. It was found that Bacillus sp. was floating at an altitude of 3,500 m over Noto Peninsula.
    Asian Journal of Atmospheric Environment. 09/2011; 5(3).
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    ABSTRACT: Bjerkandera adusta (B. adusta) is one of the most important etiological fungi associated with chronic cough. However, precise details of the inflammatory response to exposure are not well understood yet. B. adusta was recently identified in Asian sand dust (ASD) aerosol. Therefore, in the present study the exacerbating effects of ASD on B. adusta-induced lung inflammation and B. adusta + ASD on ovalbumin (OVA)-induced murine lung eosinophilia were investigated using experimental mice. In order to prepare testing samples, B. adusta obtained from ASD aerosol was inactivated by formalin and ASD collected from the atmosphere was heated to remove toxic organic substances (H-ASD). CD-1 mice were instilled intratracheally with 12 different samples prepared with various combinations of B. adusta, H-ASD, and OVA in a normal saline solution. The lung pathology, cytological profiles in bronchoalveolar lavage fluid (BALF), and the levels of inflammatory cytokines/chemokines in BALF were investigated. H-ASD aggravated the lung eosinophilia induced by B. adusta alone, which also aggravated the lung eosinophilia induced by OVA. The mixture of OVA, H-ASD, and B. adusta caused serious fibrous thickening of the subepithelial layer, eosinophil infiltration, and proliferation of goblet cells in the airways along with remarkable increases of IL-13, eotaxin, IL-5, and MCP-3 in BALF. The results of the present study demonstrated that B. adusta isolated from ASD aerosol induces allergic lung diseases. H-ASD enhanced allergic reactions caused by OVA or B. adusta. A mixture of B. adusta, H-ASD, and OVA caused the most remarkable exacerbation to the allergic airway inflammation via remarkable increases of pro-inflammatory mediators.
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    ABSTRACT: Viable bacteria on water-insoluble airborne particles were detected in the urban atmosphere of Kumamoto (), Japan, in autumn 2008. Airborne particles were collected onto film-covered Cu meshes under clear weather conditions. The samples were stained by fluorescent stains, and then viewed and photographed with an epifluorescent microscope. Non-biological and bacterial parts in particles larger than 0.8 were distinguished by their morphologies, fluorescent colors and fluorescent intensities. Bacterial viable statuses were discriminated according to cell membrane damage. In total, 2681 particles were investigated and it was found that 78 airborne particles were associated with bacteria. Viable bacteria were identified on 48 particles. A few particles carried multiple viable bacteria. These results provide the evidence that airborne particles act as carriers of viable bacteria in the atmosphere.
    Asian Journal of Atmospheric Environment. 09/2011; 5(3).

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