Antarctic ice sheet as an object for solving some methodological problems of exobiology

Abyzov, S.S.; Mitskevich, Irina N; Poglazova, M. N.; Barkov, N. I.; Lipenkov, V. Ya.; Bobin, N.E.; Kudryashov, B.B.; Pashkevich, V.M.

doi:10.1016/s0273-1177(99)00058-7

Cited by 11 publications

(4 citation statements)

References 3 publications

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“…Certain extreme environments on Earth are considered close approximations to those found on Mars or Europa. Antarctic ice sheets, for example, have been treated as a model for these planetary systems (Abyzov et al , 1999; Horneck, 2000).…”

Section: Introductionmentioning

confidence: 99%

Quantification of viable endospores from a Greenland ice core

Yung

Shafaat

Connon

et al. 2007

FEMS Microbiology Ecology

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Endospores (i.e., bacterial spores) embedded in polar ices present an opportunity to investigate the most durable form of life in an ideal medium for maintaining long-term viability. However, little is known about the endospore distribution and viability in polar ices. We have determined germinable endospore concentrations of bacterial spores capable of germination in a Greenland ice core (GISP2 94 m, ID# G2-271) using two complementary endospore viability assays (EVA), recently developed in our laboratory. These assays are based on bulk spectroscopic analysis (i.e., spectroEVA), and direct microscopic enumeration (i.e., microEVA) of ice core concentrates. Both assays detect dipicolinic acid (DPA) release during l-alanine induced germination via terbium ion (Tb3+)-DPA luminescence. Using spectroEVA, the germinable and total bacterial spore concentrations were found to be 295+/-19 spores mL(-1) and 369+/-36 spores mL(-1), respectively, (i.e., 80% of the endospores were capable of germination). Using microEVA, the germinating endospore concentration was found to be 27+/-2 spores mL(-1). The total cell concentration, as determined by DAPI stain fluorescence microscopy, was 7.0 x 10(3)+/-6.7 x 10(2) cells mL(-1). Culturing attempts yielded 2 CFU mL(-1) (4 degrees C). We conclude that endospores capable of germination in the GISP2 ice cores are readily determined using novel endospore viability assays.

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Section: Introductionmentioning

confidence: 99%

Quantification of viable endospores from a Greenland ice core

Yung

Shafaat

Connon

et al. 2007

FEMS Microbiology Ecology

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“…Another possible obstacle in using FISH is that the low physiological activity can result in low signal intensity, since the contents of rRNA (as target for the probe) varies considerably in cells of one strain in different physiological states, and non-growing cells contain low rRNA Partially for these reasons (but not only), dormant cells may not be directed by FISH until special procedures are used, for example, to recover these cells from dormancy. In our opinion, the serious difficulty for application of FISH method can be due to a typically low content of microorganisms in Antarctic ice sheet and accreted ice as demonstrated by us and other authors (Abyzov et al, 1999, Karl et al. 1999 and P -, In situ identification of viable microorganisms by PCR and FISH gives no information about the state in which they exist in cold habitats, such as Antarctic and Arctic permafrost or Antarctic glacier.…”

Section: Resultsmentioning

confidence: 82%

Super-long anabiosis of ancient microorganisms in ice and terrestrial models for development of methods to search for life on Mars, Europa and other planetary bodies

Abyzov

Duxbury

Bobin

et al. 2006

Advances in Space Research

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“…Endospores are the most resilient form of microbial life. We obtained samples from two extreme environments: Greenland, which is considered an analog to icy worlds (e.g., Europa and Enceladus) (1,10), and the Atacama Desert, Chile, which is considered a Mars analog site (18,29). The validated micro-EVA approach was used successfully to measure germinable Clostridium endospores from samples of these extreme environments, while culturing yielded mostly negative growth results.…”

Section: Resultsmentioning

confidence: 99%

Validation of a Clostridium Endospore Viability Assay and Analysis of Greenland Ices and Atacama Desert Soils

Yang

Ponce

2011

Appl Environ Microbiol

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A microscopy-based endospore viability assay (micro-EVA) capable of enumerating germinable Clostridium endospores (GCEs) in less than 30 min has been validated and employed to determine GCE concentrations in Greenland ices and Atacama Desert soils. Inoculation onto agarose doped with Tb 3؉ and D-alanine triggers Clostridium spore germination and the concomitant release of ϳ10 8 molecules of dipicolinic acid (DPA) per endospore, which, under pulsed UV excitation, enables enumeration of resultant green Tb 3؉ -DPA luminescent spots as GCEs with time-gated luminescence microscopy. The intensity time courses of the luminescent spots were characteristic of stage I Clostridium spore germination dynamics. Micro-EVA was validated against traditional CFU cultivation from 0 to 1,000 total endospores/ml (i.e., phase-bright bodies/ml), yielding 56.4% ؎ 1.5% GCEs and 43.0% ؎ 1.0% CFU. We also show that D-alanine serves as a Clostridium-specific germinant (three species tested) that inhibits Bacillus germination of spores (five species tested) in that endospore concentration regime. Finally, GCE concentrations in Greenland ice cores and Atacama Desert soils were determined with micro-EVA, yielding 1 to 2 GCEs/ml of Greenland ice (versus <1 CFU/ml after 6 months of incubation) and 66 to 157 GCEs/g of Atacama Desert soil (versus 40 CFU/g soil).

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Antarctic ice sheet as an object for solving some methodological problems of exobiology

Cited by 11 publications

References 3 publications

Quantification of viable endospores from a Greenland ice core

Quantification of viable endospores from a Greenland ice core

Super-long anabiosis of ancient microorganisms in ice and terrestrial models for development of methods to search for life on Mars, Europa and other planetary bodies

Validation of a Clostridium Endospore Viability Assay and Analysis of Greenland Ices and Atacama Desert Soils

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