Organisms from Extreme Environments

Bacteria in thawed ice samples from Ellesmere Island (79°38 N, 74°23 W) produced CO2 and CH4 during extended incubation at 4°C in a diluted complex medium (yeast extract, casamino acids, starch, and glucose) (Skidmore et al. 2000). It was suggested that the results demonstrated that the subglacial environment beneath a polythermal glacier provided an acceptable habitat for microbial life. 

Two different investigations have been directed to a glacial ice core (GISP2) from Greenland  

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Although much emphasis has been placed on isolating organisms from extreme environments in the search for novel biocatalysts, the general marine environment should not be ignored. Both micro- and macroalgae have been demonstrated to produce novel enzymes with possible applications in biocatalysis such as the haloperoxidases, enzymes capable of... 

More recently, a plethora of small companies and biotechnology ventures were established to handle biologies as well as natural products, many of them with proprietary screening platforms designed to make natural product screening more straightforward and quicker. Some developed proprietary collections of particular natural product sources for extract production such as organisms isolated from extreme environments, leaf litter, caves, unique water environments, and endophytes from marine and terrestrial plants. 

Traditionally, potentially commercial enzymes are identified by screening micro-organisms, which are frequently isolated from extreme environments, for biocatalytic activity. Commercial enzymes are selected by probing libraries of related enzymes for a range of properties, including activity, substrate specificity, stability over a temperature range, enantio-selectivity, or compatibility under various physical and chemical conditions. Unfortunately, most of the commercially viable enzymes have been isolated in only a few microbial species such as Bacillus and Pseudomonas because... 

Mounting so cial, p olitical a nd e nvironmental p ressures on i ndustry t o provide alternatives to chemical-based methods, have given added impetus to the search for novel enzymes with unique and industrially significant traits. Thus, numerous organisms have been isolated from extreme environments. From the frosty A ntarctic ice fields to t he fiery v olcanic p ools, these o rganisms p ossess unique survival kits that allow them to survive under these extreme conditions. In most cases, adaptation to such extreme environments has not required completely new molecular machinery in fact many "extremophilic enzymes are similar to dieir mesophilic counterparts found in more hospitable environment. Sequence comparisons indicate that these enzymes are derived from a common... 

Extremophile an organism that is isolated from an extreme environment and often requires the extreme condition for growth. 

Many bacteria secrete compounds called siderophores specifically to sequester iron either from the environment or from other organisms. Siderophores show extremely high affinities... 

B.P. The results of the analyses for strontium and barium are shown in Figures 3 and 4. These two populations represent the same types of organisms in similar environments, the main difference between the two sites being age. The Wawawii results show a variation in both strontium and barium concentrations that is consistent with data from several archaeological sites (13 16,17). The Lind Coulee results, on the other hand, show extreme internal variations in both strontium and barium concentrations. At present neither elk nor bison occur in the immediate vicinity of these sites. The Wawawii elk are consistent with modem elk from nearby Northern Idaho (13,16). However, only the lower end of the Lind Coulee distribution is similarly consistent. 

For in vitro assays, it is extremely difficult to determine the relevant intracellular concentrations of substrates due to compartmentalization of particular reactions, competing reactions that produce and consume common substrates, and metabolic channeling (Albe et al, 1990 Srere, 1987). Consequently, in vitro kinetic measurements may not be very useful for assessing in situ or in vivo reaction rates. However, provided assays conditions are carefully controlled, kinetic parameters may be very useful for characterizing enzyme isoforms and enzymes from different metabolic pools, different organisms, or from organisms collected from different environments. 

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