16 research outputs found
Deep sub-seafloor prokaryotes stimulated at interfaces over geological time
The sub-seafloor biosphere is the largest prokaryotic habitat
on Earth1 but also a habitat with the lowest metabolic rates2.
Modelled activity rates are very low, indicating that most prokaryotes
may be inactive or have extraordinarily slow metabolism2.
Here we present results from two Pacific Ocean sites,
margin and open ocean, both of which have deep, subsurface
stimulation of prokaryotic processes associated with geochemical
and/or sedimentary interfaces. At 90m depth in the margin site,
stimulation was such that prokaryote numbers were higher (about
13-fold) and activity rates higher than or similar to near-surface
values. Analysis of high-molecular-mass DNA confirmed the
presence of viable prokaryotes and showed changes in biodiversity
with depth that were coupled to geochemistry, including a marked
community change at the 90-m interface. At the open ocean
site, increases in numbers of prokaryotes at depth were more
restricted but also corresponded to increased activity; however, this
time they were associated with repeating layers of diatomrich
sediments (about 9Myr old). These results show that deep
sedimentary prokaryotes can have high activity, have changing
diversity associated with interfaces and are active over geological
timescales
Effects of metal-on-metal wear on the host immune system and infection in hip arthroplasty
Methods We reviewed the available literature on the influence of degradation products of MOM bearings in total hip arthroplasties on infection risk. Results Wear products were found to influence the risk of infection by hampering the immune system, by inhibiting or accelerating bacterial growth, and by a possible antibiotic resistance and heavy metal co-selection mechanism. Interpretation Whether or not the combined effects of MOM wear products make MOM bearings less or more prone to infection requires investigation in the near future