Mixture of Kosa (Asian dust) and bioaerosols detected in the atmosphere over the Kosa particles source regions with balloon-borne measurements: possibility of long-range transport

金沢大学フロンティアサイエンス機構Long-range transport of atmospheric microbiota with Asian dust (Kosa) particles is of great concern in Northeast Asia in view of the health effect of Kosa particles on human being, disturbance of ecosystems caused through invasion of new microbe, contribution of microorganisms to biogeochemical cycle on global/regional scales, and others. Information on atmospheric microbes over the desert areas has been desired for a long time. Detection of atmospheric microbiota on the desert regions, on the base of balloon-borne measurements, has been made at Dunhuang, China (40°00′ N, 94°30′ E; east end of Taklamakan desert) in the summer of 2007. The measurements showed that microbiota mixed internally with Kosa particles were frequently floating from the ground to about 2-km heights (above sea level), and possible long-range transport of atmospheric microbiota with dust particles taking local circulations is strongly suggested, causing active mixing of atmospheric dust over the Taklamakan desert from the ground to the free troposphere where westerly jet dominates (Iwasaka et al. in J Geophys Res 108:8652, 2003a, J Geophys Res 108:8644, b). The concentration of the mixed particles of Kosa and microbiota having a size larger than about 1 μm in diameter is estimated to be about 1 particle/cm3 at those heights on the basis of measurements of particle concentration with an optical particle counter and analysis of particles having fluorescence light due to dye of DAPI (4′6-diamidino-2 phenylindole) with an epifluorescence microscope. The mixing situation of microbiota and Kosa particles is the important factor controlling atmospheric lifetime of floating microbiota, since the mixing state certainly can protect microbiota from stressful environments [dryness, solar ultraviolet (UV) radiation, low temperature] in the atmosphere, and therefore, it is useful to discuss the data of the first description of microbiota in the atmosphere on the Taklamakan desert. © 2009 Springer Science+Business Media B.V

Identification, Characterisation and Specificity of a Cell Wall Lytic Enzyme from Lactobacillus Fermentum BR11

Screening of a genomic library with an antiserum raised against whole Lactobacillus fermentum BR11 cells identified a clone expressing an immunoreactive 37-kDa protein. Analysis of the 3010-bp DNA insert contained within the clone revealed four open reading frames (ORFs). One ORF encodes LysA, a 303 amino acid protein which has up to 35% identity with putative endolysins from prophages Lj928 and Lj965 from Lactobacillus johnsonii and Lp1 and Lp2 from Lactobacillus plantarum as well as with the endolysin of Lactobacillus gasseri bacteriophage Phiadh. The immunoreactive protein was shown to be encoded by a truncated ORF downstream of lysA which has similarity to glutamyl-tRNA synthetases. The N-terminus of LysA has sequence similarity with N-acetylmuramidase catalytic domains while the C-terminus has sequence similarity with putative cell envelope binding bacterial SH3b domains. C-terminal bacterial SH3b domains were identified in the majority of Lactobacillus bacteriophage endolysins. LysA was expressed in Escherichia coli and unusually was found to have a broad bacteriolytic activity range with activity against a number of different Lactobacillus species and against Lactococcus lactis, streptococci and Staphylococcus aureus. It was found that LysA is 2 and 8000 times more active against L. fermentum than L. lactis and Streptococcus pyogenes, respectively