67 research outputs found

    Nowhere safe? Exploring the influence of urbanization across mainland and insular seashores in continental Portugal and the Azorean Archipelago

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    Differences in the structure and functioning of intensively urbanized vs. less human-affected systems are reported, but such evidence is available for amuch larger extent in terrestrial than in marine systems.Weexamined the hypotheses that (i) urbanization was associated to different patterns of variation of intertidal assemblages between urban and extra-urban environments; (ii) such patterns were consistent acrossmainland and insular systems, spatial scales from 10s cm to 100s km, and a three months period. Several trends emerged: (i) a more homogeneous distribution of most algal groups in the urban compared to the extra-urban condition and the opposite pattern of most invertebrates; (ii) smaller/larger variances of most organisms where these were, respectively, less/more abundant; (iii) largest variability of most response variables at small scale; (iv) no facilitation of invasive species by urbanization and larger cover of canopy-forming algae in the insular extra-urban condition. Present findings confirmthe acknowledged notion that futuremanagement strategieswill require to include representative assemblages and their relevant scales of variation associated to urbanization gradients on both the mainland and the islands

    Cheating the locals: invasive mussels steal and benefit from the cooling effect of indigenous mussels

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    The indigenous South African mussel Perna perna gapes during periods of aerial exposure to maintain aerobic respiration. This behaviour has no effect on the body temperatures of isolated individuals, but when surrounded by conspecifics, beneficial cooling effects of gaping emerge. It is uncertain, however, whether the presence of the invasive mussel Mytilus galloprovincialis limits the ability of P. perna for collective thermoregulation. We investigated whether varying densities of P. perna and M. galloprovincialis influences the thermal properties of both natural and artificial mussel beds during periods of emersion. Using infrared thermography, body temperatures of P. perna within mixed artificial beds were shown to increase faster and reach higher temperatures than individuals in conspecific beds, indicating that the presence of M. galloprovincialis limits the group cooling effects of gaping. In contrast, body temperatures of M. galloprovincialis within mixed artificial mussel beds increased slower and exhibited lower temperatures than for individuals in beds comprised entirely of M. galloprovincialis. Interestingly, differences in bed temperatures and heating rates were largely dependent on the size of mussels, with beds comprised of larger individuals experiencing less thermal stress irrespective of species composition. The small-scale patterns of thermal stress detected within manipulated beds were not observed within naturally occurring mixed mussel beds. We propose that small-scale differences in topography, size-structure, mussel bed size and the presence of organisms encrusting the mussel shells mask the effects of gaping behaviour within natural mussel beds. Nevertheless, the results from our manipulative experiment indicate that the invasive species M. galloprovincialis steals thermal properties as well as resources from the indigenous mussel P. perna. This may have significant implications for predicting how the co-existence of these two species may change as global temperatures continue to rise

    A Catalytic Mechanism for Cysteine N-Terminal Nucleophile Hydrolases, as Revealed by Free Energy Simulations

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    The N-terminal nucleophile (Ntn) hydrolases are a superfamily of enzymes specialized in the hydrolytic cleavage of amide bonds. Even though several members of this family are emerging as innovative drug targets for cancer, inflammation, and pain, the processes through which they catalyze amide hydrolysis remains poorly understood. In particular, the catalytic reactions of cysteine Ntn-hydrolases have never been investigated from a mechanistic point of view. In the present study, we used free energy simulations in the quantum mechanics/molecular mechanics framework to determine the reaction mechanism of amide hydrolysis catalyzed by the prototypical cysteine Ntn-hydrolase, conjugated bile acid hydrolase (CBAH). The computational analyses, which were confirmed in water and using different CBAH mutants, revealed the existence of a chair-like transition state, which might be one of the specific features of the catalytic cycle of Ntn-hydrolases. Our results offer new insights on Ntn-mediated hydrolysis and suggest possible strategies for the creation of therapeutically useful inhibitors

    Septic AKI in ICU patients. diagnosis, pathophysiology, and treatment type, dosing, and timing: a comprehensive review of recent and future developments

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    Evidence is accumulating showing that septic acute kidney injury (AKI) is different from non-septic AKI. Specifically, a large body of research points to apoptotic processes underlying septic AKI. Unravelling the complex and intertwined apoptotic and immuno-inflammatory pathways at the cellular level will undoubtedly create new and exciting perspectives for the future development (e.g., caspase inhibition) or refinement (specific vasopressor use) of therapeutic strategies. Shock complicating sepsis may cause more AKI but also will render treatment of this condition in an hemodynamically unstable patient more difficult. Expert opinion, along with the aggregated results of two recent large randomized trials, favors continuous renal replacement therapy (CRRT) as preferential treatment for septic AKI (hemodynamically unstable). It is suggested that this approach might decrease the need for subsequent chronic dialysis. Large-scale introduction of citrate as an anticoagulant most likely will change CRRT management in intensive care units (ICU), because it not only significantly increases filter lifespan but also better preserves filter porosity. A possible role of citrate in reducing mortality and morbidity, mainly in surgical ICU patients, remains to be proven. Also, citrate administration in the predilution mode appears to be safe and exempt of relevant side effects, yet still requires rigorous monitoring. Current consensus exists about using a CRRT dose of 25 ml/kg/h in non-septic AKI. However, because patients should not be undertreated, this implies that doses as high as 30 to 35 ml/kg/h must be prescribed to account for eventual treatment interruptions. Awaiting results from large, ongoing trials, 35 ml/kg/h should remain the standard dose in septic AKI, particularly when shock is present. To date, exact timing of CRRT is not well defined. A widely accepted composite definition of timing is needed before an appropriate study challenging this major issue can be launched

    The Rotterdam Study: 2010 objectives and design update

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    The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods

    RhoC-GTPase is a Novel Tissue Biomarker Associated with Biologically Aggressive Carcinomas of the Breast

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    Background. There is a need for reliable predictors of breast cancer aggressiveness that will further refine the staging classification and help guide the implementation of novel therapies. We have identified RhoC as being nearly always overexpressed in the most aggressive form of breast cancer, inflammatory breast cancer (IBC); in subsequent work we identified RhoC to be a promising marker of aggressive behavior in breast cancers less than 1 cm in diameter. We hypothesized that RhoC expression would identify aggressive, non-IBC tumors breast cancer patients at any stage with worse outcomes defined as recurrence and/or metastasis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44231/1/10549_2005_Article_4170.pd
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