Role of Polyphosphates in Microbial Adaptation to Extreme Environments

Anthropomorphically, an extreme environment is one in which physical conditions are not conducive for human life. In this review, extreme environments are defined as habitats that experience steady or fluctuating exposure to one or more environmental factors, such as salinity, osmolarity, desiccation, UV radiation, barometric pressure, pH, and temperature. Microorganisms that colonize extreme environments are called extremophiles, and they are categorized into subgroups according to the specific environmental characteristics of their habitats (for a review, see reference 78). Prokaryotic and eukaryotic microorganisms provide sources for the discovery of novel biochemical pathways and biomolecules that allow microbes to adapt to extreme environmental conditions. Previous studies of microorganisms from extreme environments have led to the development of important industrial processes and the discovery of health-promoting biomolecules. Examples include biochemicals used for detergent formulations, leather and paper processing, biofuels, bioremediation, UV-blocking, and new antibiotics (1, 17, 27, 28, 57, 93). Potentially beneficial biomolecules still remain to be discovered from unexplored extreme environments. One such environment is the high-altitude Andean wetland (HAAW) ecosystems of the South American Andes. The HAAW ecosystems are systems of shallow lakes formed during the Tertiary geological period. These aquatic ecosystems are distributed in the geographical area called the Puna at altitudes from 3,000 to 6,000 m above sea level, where they are isolated from direct human activity, and they are almost unexplored (Fig. 1). The HAAW ecosystems are unique not only for their geographical characteristics and broad range of extreme environments but also for their abundant biodiversity. The microbial communities that have evolved within these high-altitude aquatic ecosystems must tolerate chemical and physical stresses such as wide fluctuations in daily temperatures, hypersalinity, and variable pH and be adapted to high levels of UV radiation, a low level of nutrient availability, and high concentrations of heavy metals, especially arsenic (13, 14, 18, 19, 99). Polyphosphates (polyP), linear polymers of tens or hundreds of orthophosphate (Pi) residues linked by high-energy phosphoanhydride bonds, were apparently present on Earth before life appeared and were generated through a variety of abiotic processes (97). polyP have been associated with the capacity of microbes to resist both physical and chemical stresses (6, 39). The structural and physicochemical characteristics of polyP seem to have been criteria for the selection of these molecules as components of cellular processes during evolution (40). The early living organisms may have used polyP as long-term sources of Pi and energy. This may also have allowed microorganisms to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of bacteria to overcome stress are of increasing scientific interest. polyP are some of the first examples of membrane-bound organelles with important functional roles found in both prokaryotic and eukaryotic kingdoms. This minireview will focus on the ways that polyP, biologically versatile molecules, could be involved in the adaptation to extreme environments by modulating microbial stress responses in pristine HAAW ecosystems. These aquatic ecosystems are natural laboratories for exploring and monitoring in situ interactions between the environment and the dynamics of biodiversity. to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of bacteria to overcome stress are of increasing scientific interest. polyP are some of the first examples of membrane-bound organelles with important functional roles found in both prokaryotic and eukaryotic kingdoms. This minireview will focus on the ways that polyP, biologically versatile molecules, could be involved in the adaptation to extreme environments by modulating microbial stress responses in pristine HAAW ecosystems. These aquatic ecosystems are natural laboratories for exploring and monitoring in situ interactions between the environment and the dynamics of biodiversity. bonds, were apparently present on Earth before life appeared and were generated through a variety of abiotic processes (97). polyP have been associated with the capacity of microbes to resist both physical and chemical stresses (6, 39). The structural and physicochemical characteristics of polyP seem to have been criteria for the selection of these molecules as components of cellular processes during evolution (40). The early living organisms may have used polyP as long-term sources of Pi and energy. This may also have allowed microorganisms to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of bacteria to overcome stress are of increasing scientific interest. polyP are some of the first examples of membrane-bound organelles with important functional roles found in both prokaryotic and eukaryotic kingdoms. This minireview will focus on the ways that polyP, biologically versatile molecules, could be involved in the adaptation to extreme environments by modulating microbial stress responses in pristine HAAW ecosystems. These aquatic ecosystems are natural laboratories for exploring and monitoring in situ interactions between the environment and the dynamics of biodiversity. to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of bacteria to overcome stress are of increasing scientific interest. polyP are some of the first examples of membrane-bound organelles with important functional roles found in both prokaryotic and eukaryotic kingdoms. This minireview will focus on the ways that polyP, biologically versatile molecules, could be involved in the adaptation to extreme environments by modulating microbial stress responses in pristine HAAW ecosystems. These aquatic ecosystems are natural laboratories for exploring and monitoring in situ interactions between the environment and the dynamics of biodiversity. i) residues linked by high-energy phosphoanhydride bonds, were apparently present on Earth before life appeared and were generated through a variety of abiotic processes (97). polyP have been associated with the capacity of microbes to resist both physical and chemical stresses (6, 39). The structural and physicochemical characteristics of polyP seem to have been criteria for the selection of these molecules as components of cellular processes during evolution (40). The early living organisms may have used polyP as long-term sources of Pi and energy. This may also have allowed microorganisms to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of bacteria to overcome stress are of increasing scientific interest. polyP are some of the first examples of membrane-bound organelles with important functional roles found in both prokaryotic and eukaryotic kingdoms. This minireview will focus on the ways that polyP, biologically versatile molecules, could be involved in the adaptation to extreme environments by modulating microbial stress responses in pristine HAAW ecosystems. These aquatic ecosystems are natural laboratories for exploring and monitoring in situ interactions between the environment and the dynamics of biodiversity. to survive Earth’s primitive environment, which resembled some of Earth’s current extreme environments. polyP granules or bodies (volutin granules, which stain red when treated with toluidine blue) are widely distributed among microbial species. Granules of polyP are homologous to the acidocalcisome, an organelle involved specifically in the storage and metabolism of cellular polyP (15). The association of acidocalcisomes with phosphorous metabolism and evidence that links polyP with the capacity of ba