Understanding the link between microbial diversity and ecosystem processes is a fundamental goal of microbial ecologists, yet we still have a rudimentary knowledge of how changes in diversity affect nutrient cycling and energy transfer in ecosystems. Due to the complexity of the problem, many published studies on this topic have been conducted in artificial or manipulated systems. Studies of ar...

DsbA, a member of the thioredoxin family of disulfide oxidoreductases, acts in catalyzing disulfide bond formation by donating its disulfide to newly translocated proteins. We have found that the two central residues within the active site Cys-30-Pro-31-His-32-Cys-33 motif are critical in determining the exceptional oxidizing power of DsbA. Mutations that change these two residues can alter the...

Indirect UV-absorption spectrometry was shown to be a valuable tool for chemical characterization of functionalized carbon nanotubes (CNTs). It complements data from X-ray photoelectron spectroscopy (XPS) or FTIR analysis since it helps to clarify the type and concentration of functional groups. The principles of indirect application of UV-spectrometry and its mathematical interpretation are di...

Nitrosomonas europaea, an obligate ammonia-oxidizing bacterium, lost an increasing amount of ammonia oxidation activity upon exposure to increasing concentrations of nitrite, the primary product of ammonia-oxidizing metabolism. The loss of activity was specific to the ammonia monooxygenase (AMO) enzyme, as confirmed by a decreased rate of NH4+-dependent O2 consumption, some loss of active AMO m...

The discovery of ammonia-oxidizing archaea (AOA), now generally recognized to exert primary control over ammonia oxidation in terrestrial, marine, and geothermal habitats, necessitates a reassessment of the nitrogen cycle. In particular, the unusually high affinity of marine and terrestrial AOA for ammonia indicates that this group may determine the oxidation state of nitrogen available to asso...

Bacterial isolates assigned to the species Alicyclobacillus tolerans, which occupies an intermediate position between organotrophic genus and mixotrophic Sulfobacillus, were revealed as members of acidophilic chemolithotrophic community during stirred-tank bioleaching violarite–pentlandite–chalcopyrite concentrate at 40 °C. Surprisingly, this succeeded more common iron-oxidizing after a series ...

Tor Caldara is a shallow-water gas vent located in the Mediterranean Sea, with active venting of CO 2 and H S. At Caldara, filamentous microbial biofilms, mainly composed Epsilon- Gammaproteobacteria , grow on substrates exposed to venting. In this study, we took metaproteogenomic approach identify metabolic potential situ expression central pathways at two stages biofilm maturation. Our findin...

Current evidence suggests that O2- and H2O2 injure cells as a result of the generation of a more potent oxidizing species. In addition to O2- and H2O2, the third essential component of the complex that mediates the lethal cell injury is a cellular source of ferric iron. The hypothesis most consistent with all the available data suggests that O2- reduces a cellular source of ferric to ferrous ir...

Nitrospira are the most widespread and diverse known nitrite-oxidizing bacteria and key nitrifiers in natural and engineered ecosystems. Nevertheless, their ecophysiology and environmental distribution are understudied because of the recalcitrance of Nitrospira to cultivation and the lack of a molecular functional marker, which would allow the detection of Nitrospira in the environment. Here we...

The active participation of ROS in the reproductive physiology flowering plants is well-documented model species, mainly with dry stigmas. Here we studied release into stigma exudate—a fluid involved pollen acceptance on a wet stigma. study from different systematic groups: Paeonia suffruticosa, Nicotiana tabacum, Lilium hybr., Aristolochia manshuriensis and Berberis vulgaris; most cases, exuda...