Comparison of microbial communities associated with three Atlantic ultramafic hydrothermal systems.

The distribution of Archaea and methanogenic, methanotrophic and sulfate-reducing communities in three Atlantic ultramafic-hosted hydrothermal systems (Rainbow, Ashadze, Lost City) was compared using 16S rRNA gene and functional gene (mcrA, pmoA and dsrA) clone libraries. The overall archaeal community was diverse and heterogeneously distributed between the hydrothermal sites and the types of samples analyzed (seawater, hydrothermal fluid, chimney and sediment). The Lost City hydrothermal field, characterized by high alkaline warm fluids (pH>11; T<95 °C), harbored a singular archaeal diversity mostly composed of unaffiliated Methanosarcinales.

Culturing marine bacteria - an essential prerequisite for biodiscovery.

The potential for using marine microbes for biodiscovery is severely limited by the lack of laboratory cultures. It is a long-standing observation that standard microbiological techniques only isolate a very small proportion of the wide diversity of microbes that are known in natural environments from DNA sequences. A number of explanations are reviewed.

Pyrococcus yayanosii sp. nov., an obligate piezophilic hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent.

An obligate piezophilic anaerobic hyperthermophilic archaeon, designated strain CH1(T), was isolated from a hydrothermal vent site named 'Ashadze', which is located on the Mid-Atlantic Ridge at a depth of 4100 m. Enrichment and isolation of the strain were carried out at 95 °C under a hydrostatic pressure of 42 MPa. Cells of strain CH1(T) were highly motile irregular cocci with a diameter of ~1-1.

New insight into the contributions of thermogenic processes and biogenic sources to the generation of organic compounds in hydrothermal fluids.

Experiments on hydrothermal degradation of Pyrococcus abyssi biomass were conducted at elevated pressure (40 MPa) over a 200-450 °C temperature range in sapphire reaction cells. Few organic compounds could be detected in the 200 °C experiment. This lack was attributed to an incomplete degradation of P.

Binding to PCNA in Euryarchaeal DNA Replication requires two PIP motifs for DNA polymerase D and one PIP motif for DNA polymerase B.

Replicative DNA polymerases possess a canonical C-terminal proliferating cell nuclear antigen (PCNA)-binding motif termed the PCNA-interacting protein (PIP) box. We investigated the role of the PIP box on the functional interactions of the two DNA polymerases, PabPol B (family B) and PabPol D (family D), from the hyperthermophilic euryarchaeon Pyrococcus abyssi, with its cognate PCNA. The PIP box was essential for interactions of PabPol B with PCNA, as shown by surface plasmon resonance and primer extension studies.