the dating game theme - Thermoluminescence dating of a deep sea sediment core

Molecular studies based on the phylogenetic analysis of environmentally derived 16S r RNA genes (r DNA) can bypass the limitations of culture-dependent approaches and offer an increasingly comprehensive picture of diversity and distribution of microbial populations (57).

thermoluminescence dating of a deep sea sediment core-36thermoluminescence dating of a deep sea sediment core-10

The RNA was precipitated with 2 volumes of ethanol and was collected by centrifugation, washed in 80% ethanol, dried, and resuspended in RNase-free sterile distilled water.

A plasmid containing clone CRA7-0 cm was linearized with HI and in vitro transcribed with T7 RNA polymerase (Stratagene Cloning Systems, La Jolla, Calif.) to generate archaeal reference r RNA, and the integrity of the transcript was checked on a denaturing agarose gel.

Although several recent studies have focused on the characterization of microbial communities involved in carbon and sulfur cycling in coastal benthic environments (13, 24, 34, 42, 54), microbial populations in deep-sea sediments remain poorly studied.

This is particularly true for the , whose population structure, global distribution, and possible contribution to postdepositional diagenesis in deep-sea sediments are virtually unknown.

These results may reflect a rich physiological diversity associated with Deep-sea sediments were collected from different locations in the northwestern Atlantic Ocean (Table1).

Acrylic tube cores were collected on the continental rise (CR) at the Long-term Ecosystem Observatory 2500 (LEO 2500), from the DSV were collected on the Atlantis Canyon (AC; 1,500 m) and on the abyssal plain (AP; 4,500 m).Quantitative oligonucleotide hybridization experiments indicated that the relative abundance of archaeal 16S r RNA in deep-sea sediments (1500 m deep) ranged from about 2.5 to 8% of the total prokaryotic r RNA.Clone libraries of PCR-amplified archaeal r RNA genes (r DNA) were constructed from 10 depth intervals obtained from sediment cores collected at depths of 1,500, 2,600, and 4,500 m., 50 m M EDTA; p H 5.1), 500 μl of phenol (p H 5.1), 35 μl of sodium dodecyl sulfate (SDS), and 0.5 g of zirconium beads (Biospec, Inc., Bartlesville, Okla.).The RNA was extracted by two bead-beating treatments and two extractions with phenol (p H 5.1), phenol-chloroform-isoamyl alcohol (:1), and chloroform-isoamyl alcohol (24:1), respectively.Recently, several studies based on the comparison of 16S r RNA genes have radically changed our view of the , revealing the ubiquitous character of these microorganisms, which also appear to thrive in aquatic and terrestrial temperate environments.

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