Seasonal Variation in Airborne Microbial Concentrations and Diversity at Landfill, Urban and Rural Sites
ABSTRACT Microbes are present everywhere in outdoor air. However, the general characterization of outdoor air mycobiota and bacterial flora is incomplete. In this study, seasonal variations in outdoor air microbial concentrations and differences between a landfill, urban and rural sites were compared. Samples were collected monthly for a period of one year. Airborne dust samples were collected onto polyvinyl chloride filters. Filter samples were analyzed for ergosterol, and 14 species or assay groups of fungi and for the bacterial genus Streptomyces by using quantitative PCR. Viable bacteria and fungi were collected with a cascade impactor twice each month from the three sampling sites. The concentrations in the different sampling sites varied depending on the species. The concentrations of Penicillium and Aspergillus species were significantly higher in the waste center compared with the other sites, while the concentration of Cladosporium spp. was highest in the rural area. The highest concentrations of Streptomyces and Cladosporium species were observed in warmer weather periods. Similar observations were made for ergosterol. Group and species seasonal variation was less distinct for Penicillium and Aspergillus. According to the present results, both season and environment are determinants of microbial communities in outdoor air.
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ABSTRACT: Antibodies are a well-established class of affinity reagents used extensively in detection and diagnostic applications. However, while these proteins have been developed to provide considerable functionality in conventional applications (e.g. sandwich ELISA), their exploitation in emergent biosensor technologies requires careful consideration. Historically, diagnostic technologies have been the primary consumer of antibody products. As a result, antibody development has been skewed toward satisfying the requirements of conventional diagnostic assay formats (ostensibly sandwich assays). The resulting catalogue of antibody products provides a convenient resource for potential biosensor exploitation. However, when applied outside of their traditional context (on novel surface/transducer interfaces) they can behave unpredictably and undesirably (e.g. loss of activity or specificity). The surface immobilisation of a recognition element within a biosensor is an invariant feature of biosensor assay design. The resulting interface represents a complex system composed of interdependent technical challenges affecting assay stability, specificity, and sensitivity. It is likely that a holistic approach to interface development is required as the development of individual interface components is unlikely to deliver the technical advances required for the practical exploitation/commercialization of biosensor technologies. The use of antibodies in biosensor applications requires a detailed understanding of their inherent properties and the interface to which they are to be tethered. This chapter illustrates the core properties of antibody structure and function and their significance in biosensing applications. The different classes of antibody reagents available to biosensor developers are discussed with a focus on recombinant antibody technologies. The opportunities available in biosensor development, regarding assay and interface design, are briefly considered. Finally, strategies for the bespoke engineering and application of antibodies in biosensor technologies are discussed in detail. KeywordsAntibody engineering-Biosensor interface-Stability-Affinity-Specificity-Sensitivity-Immobilisation-Monoclonal-Polyclonal-Recombinant antibody-Domain antibody12/2009: pages 451-529;
- American journal of men's health 10/2011; 8(3):227-227. · 1.15 Impact Factor
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ABSTRACT: The atmosphere is host to an omnipresent bacterial community that may influence fundamental atmospheric processes such as cloud formation and precipitation onset. Knowledge of this bacterial com-munity is scarce, particularly in air masses relevant to cloud formation. Using a light aircraft, we sampled above the atmospheric boundary layer—that is, at heights at which cloud condensation occurs—over coastal areas of Sweden and Denmark in summer 2009. Enumeration indicated total bacterial numbers of 4 9 10 1 to 1.8 9 10 3 m -3 air and colony-forming units of 0–6 bacteria m -3 air. 16S rRNA gene libraries constructed from samples collected above the Baltic Sea coast revealed a highly diverse bacterial commu-nity dominated by species belonging to the genera Sphingomonas and Pseudomonas. Bacterial species known to carry ice-nucleating proteins were found in several samples. Modeled back trajectories suggested the potential sources of the sampled bacteria to be diverse geographic regions, including both marine and terrestrial environments in the northern hemisphere. Several samples contained 16S rRNA genes from plant chloroplasts, confirming a terrestrial contribu-tion to these samples. Interestingly, the airborne bacterial community displayed an apparent seasonal succession that we tentatively ascribe to in situ succession in the atmosphere.Aerobiologia 12/2012; 28(4):481-498. · 1.20 Impact Factor