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Lemese Ah Tow

Publications and source records attributed to Lemese Ah Tow.

5 recordsLinked to original sources
PubMed2006

Bacterial diversity in three different Antarctic Cold Desert mineral soils.

A bacterial phylogenetic survey of three environmentally distinct Antarctic Dry Valley soil biotopes showed a high proportion of so-called "uncultured" phylotypes, with a relatively low diversity of identifiable phylotypes. Cyanobacterial phylotypic signals were restricted to the high-altitude sample, whereas many of the identifiable phylotypes, such as the members of the Actinobacteria, were found at all sample sites. Although the presence of Cyanobacteria and Actinobacteria is consistent with previous culture-dependent studies of microbial diversity in Antarctic Dry Valley mineral soils, many phylotypes identified by 16S rDNA analysis were of groups that have not hitherto been cultured from Antarctic soils. The general belief that such "extreme" environments harbor a relatively low species diversity was supported by the calculation of diversity indices. The detection of a substantial number of uncultured bacterial phylotypes showing low BLAST identities (< 95%) suggests that Antarctic Dry Valley mineral soils harbor a pool of novel psychrotrophic taxa.

Antarctic Regions↗
PubMed2005

Dissemination and survival of non-indigenous bacterial genomes in pristine Antarctic environments.

Continental Antarctic is perceived as a largely pristine environment, although certain localized regions (e.g., parts of the Ross Dependency Dry Valleys) are relatively heavy impacted by human activities. The procedures imposed on Antarctic field parties for the handling and disposal of both solid and liquid wastes are designed to minimise eutrofication and contamination (particularly by human enteric bacteria). However, little consideration has been given to the significance, if any, of less obvious forms of microbial contamination resulting from periodic human activities in Antarctica. The predominant commensal microorganism on human skin, Staphylococcus epidermidis, could be detected by PCR, in Dry Valley mineral soils collected from heavily impacted areas, but could not be detected in Dry Valley mineral soils collected from low impact and pristine areas. Cell viability of this non-enteric human commensal is rapidly lost in Dry Valley mineral soil. However, S. epidermidis can persist for long periods in Dry Valley mineral soil as non-viable cells and/or naked DNA.

Antarctic Regions↗
PubMed2004

Endangered antarctic environments.

The Antarctic continent harbors a range of specialized and sometimes highly localized microbial biotopes. These include biotopes associated with desiccated mineral soils, rich ornithogenic soils, glacial and sea ice, ice-covered lakes, translucent rocks, and geothermally heated soils. All are characterized by the imposition of one or more environmental extremes (including low temperature, wide temperature fluctuations, desiccation, hypersalinity, high periodic radiation fluxes, and low nutrient status). As our understanding of the true microbial diversity in these biotopes expands from the application of molecular phylogenetic methods, we come closer to the point where we can make an accurate assessment of the impacts of environmental change, human intervention, and other natural and unnatural impositions. At present, it is possible to make reasonable predictions about the physical effects of local climate change, but only general predictions on possible changes in microbial community structure. The consequences of some direct human impacts, such as physical disruption of microbial soil communities, are obvious if not yet quantitated. Others, such as the dissemination of nonindigenous microorganisms into indigenous microbial communities, are not yet understood.

Antarctic Regions↗
PubMed2003

PCR-based detection of non-indigenous microorganisms in 'pristine' environments.

PCR-based technologies are widely employed for the detection of specific microorganisms, and may be applied to the identification of non-indigenous microorganisms in 'pristine' environments. For 'pristine' environments such as those found on the Antarctic continent, the application of these methods to the assessment of environmental contamination from human activities must be treated with caution. Issues such as the possibility of non-human dispersal of organisms, stability and survival of non-indigenous organisms in vivo, the sensitivity, reproducibility and specificity of the PCR process (and particularly primer design) and the sampling regime employed must all be considered in detail. We conclude that despite these limitations, PCR and related technologies offer enormous scope for assessment of both natural and non-indigenous microbial distributions.

Antarctic Regions↗