858 research outputs found
Microbes do not follow the elevational diversity patterns of plants and animals
The elevational gradient in plant and animal diversity is one of the most widely documented patterns in ecology and, although no consensus explanation exists, many hypotheses have been proposed over the past century to explain these patterns. Historically, research on elevational diversity gradients has focused almost exclusively on plant and animal taxa. As a result, we do not know whether microbes exhibit elevational gradients in diversity that parallel those observed for macroscopic taxa. This represents a key knowledge gap in ecology, especially given the ubiquity, abundance, and functional importance of microbes. Here we show that, across a montane elevational gradient in eastern Peru, bacteria living in three distinct habitats (organic soil, mineral soil, and leaf surfaces) exhibit no significant elevational gradient in diversity (r2 0.1 in all cases), in direct contrast to the significant diversity changes observed for plant and animal taxa across the same montane gradient (r2 > 0.75, P < 0.001 in all cases). This finding suggests that the biogeographical patterns exhibited by bacteria are fundamentally different from those of plants and animals, highlighting the need for the development of more inclusive concepts and theories in biogeography to explain these disparities
climate change and biodiversity in Amazonia: a Late-Holocene perspective
Fire is an important and arguably unnatural component of many wet Amazonian and Andean forest systems. Soil charcoal has been used to infer widespread human use of landscapes prior to European Conquest. An analysis of Amazonian soil carbon records reveals that the records have distinct spatial and temporal patterns, suggesting that either fires were only set in moderately seasonal areas of Amazonia or that strongly seasonal and aseasonal areas are undersampled. Synthesizing data from 300 charcoal records, an age-frequency diagram reveals peaks of fire apparently coinciding with some periods of very strong El Niñ o activity. However, the El Niñ o record does not always provide an accurate prediction of fire timing, and a better match is found in the record of insolation minima. After the time of European contact, fires became much scarcer within Amazonia. In both the Amazonia and the Andes, modern fire pattern is strongly allied to human activity. On the flank of the Andes, forests that have never burned are being eroded by fire spreading downslope from grasslands. Species of these same forests are being forced to migrate upslope due to warming and will encounter a firm artificial fire boundary of human activity
Efficacy and safety of anti-TNF therapies in psoriatic arthritis: an observational study from the British Society for Rheumatology Biologics Register
Objectives. To evaluate the riskâbenefit profile of anti-TNF therapies in PsA and to study the predictors of treatment response and disease remission [disease activity score (DAS)-28 < 2.6]
Informing trait-based ecology by assessing remotely sensed functional diversity across a broad tropical temperature gradient
Spatially continuous data on functional diversity will improve our ability to predict global change impacts on ecosystem properties. We applied methods that combine imaging spectroscopy and foliar traits to estimate remotelysensed functional diversity in tropical forests across an Amazon-to-Andes elevation gradient (215 to 3537 m). We evaluated the scale dependency of community assembly processes and examined whether tropical forest productivitycould be predicted by remotely sensed functional diversity. Functional richness of the community decreased withincreasing elevation. Scale-dependent signals of trait convergence, consistent with environmental filtering, play animportant role in explaining the range of trait variation within each site and along elevation. Single- and multitraitremotely sensed measures of functional diversity were important predictors of variation in rates of net and grossprimary productivity. Our findings highlight the potential of remotely sensed functional diversity to inform trait-based ecology and trait diversity-ecosystem function linkages in hyperdiverse tropical forests.Fil: DurĂĄn, Sandra M.. University of Arizona; Estados UnidosFil: Martin, Roberta E.. Arizona State University; Estados UnidosFil: DĂaz, Sandra Myrna. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - CĂłrdoba. Instituto Multidisciplinario de BiologĂa Vegetal. Universidad Nacional de CĂłrdoba. Facultad de Ciencias Exactas FĂsicas y Naturales. Instituto Multidisciplinario de BiologĂa Vegetal; ArgentinaFil: Maitner, Brian S.. Arizona State University; Estados UnidosFil: Malhi, Yadvinder. University of Oxford; Reino UnidoFil: Salinas, Norma. University of Oxford; Reino Unido. Pontificia Universidad CatĂłlica de PerĂș; PerĂșFil: Shenkin, Alexander. University of Oxford; Reino UnidoFil: Silman, Miles R.. Wake Forest University; Estados UnidosFil: Wieczynski, Daniel J.. University of Oxford; Reino UnidoFil: Asner, Gregory P.. Arizona State University; Estados UnidosFil: Bentley, Lisa Patrick. Sonoma State University; Estados UnidosFil: Savage, Van M.. University of California; Estados UnidosFil: Enquist, Brian J.. Arizona State University; Estados Unido
Musculoskeletal pain is associated with a long-term increased risk of cancer and cardiovascular-related mortality
Objectives. To test the hypothesis that individuals with regional and widespread pain disorders have an increased risk of mortality
3-D struktura serumske paraoksonaze 1 objaĆĄnjava njezinu aktivnost, stabilnost, topljivost i kristalizaciju
Serum paraoxonases (PONs) exhibit a wide range of physiologically important hydrolytic activities, including drug metabolism and detoxification of nerve gases. PON1 and PON3 reside on high-density lipoprotein (HDL) (the âgood cholesterolâ), and are involved in the alleviation of atherosclerosis. Members of the PON family have been identified not only in mammals and other vertebrates, but also in invertebrates. We earlier described the first crystal structure of a PON family member, a directly-evolved variant of PON1, at 2.2 Ă
resolution. PON1 is a 6-bladed beta-propeller with a unique active-site lid which is also involved in binding to HDL. The 3-D structure, taken together with directed evolution studies, permitted analysis of mutations which enhanced the stability, solubility and crystallizability of this PON1 variant. The structure permits a detailed description of PON1âs active site and suggests possible mechanisms for its catalytic activity on certain substrates.Serumske paraoksonaze (PONs) imaju ĆĄiroki raspon fizioloĆĄki vaĆŸnih hidrolitiÄkih aktivnosti ukljuÄujuÄi metabolizam lijekova i detoksikaciju nervnih plinova. PON1 i PON3 smjeĆĄtene su na lipoproteinima visoke gustoÄe (engl. high-density lipoprotein; HDL - âdobri kolesterolâ) i ukljuÄene su u ublaĆŸavanje ateroskleroze. Älanovi skupine PON identificirani su ne samo u sisavaca i drugih kraljeĆŸnjaka veÄ i kod beskraljeĆĄnjaka. Prije smo opisali prvu kristalnu strukturu Älana PON skupine, direktno razraÄenu varijantu PON1 pri rezoluciji 2,2 Ă
. PON1 je beta-propeler sa ĆĄest lopatica s jedinstvenim poklopcem aktivnog mjesta, koji je tako|er ukljuÄen u vezanje na HDL. 3-D struktura, gledana zajedno s direktnim razvojnim istraĆŸivanjima, omoguÄila je analizu mutacija koje poveÄavaju stabilnost, topljivost i kristalizaciju te PON1 varijante. Struktura dopuĆĄta detaljan opis aktivnog mjesta PON1 i sugerira moguÄe mehanizme za njezinu katalitiÄku aktivnost prema odre|enim supstratima
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