26 research outputs found
Climate drives the geography of marine consumption by changing predator communities
Este artĂculo contiene 7 pĂĄginas, 3 figuras, 1 tabla.The global distribution of primary production and consumption by
humans (fisheries) is well-documented, but we have no map linking
the central ecological process of consumption within food
webs to temperature and other ecological drivers. Using standardized
assays that span 105° of latitude on four continents, we show
that rates of bait consumption by generalist predators in shallow
marine ecosystems are tightly linked to both temperature and the
composition of consumer assemblages. Unexpectedly, rates of
consumption peaked at midlatitudes (25 to 35°) in both Northern
and Southern Hemispheres across both seagrass and unvegetated
sediment habitats. This pattern contrasts with terrestrial systems,
where biotic interactions reportedly weaken away from the equator,
but it parallels an emerging pattern of a subtropical peak in
marine biodiversity. The higher consumption at midlatitudes was
closely related to the type of consumers present, which explained
rates of consumption better than consumer density, biomass, species
diversity, or habitat. Indeed, the apparent effect of temperature
on consumption was mostly driven by temperature-associated turnover
in consumer community composition. Our findings reinforce
the key influence of climate warming on altered species composition
and highlight its implications for the functioning of Earthâs
ecosystems.We acknowledge funding from the Smithsonian
Institution and the Tula Foundation.Peer reviewe
ThePlasmodiumClass XIV Myosin, MyoB, Has a Distinct Subcellular Location in Invasive and Motile Stages of the Malaria Parasite and an Unusual Light Chain
Myosin B (MyoB) is one of the two short class XIV myosins encoded in the Plasmodium genome. Class XIV myosins are characterized by a catalytic âhead,â a modified âneck,â and the absence of a âtailâ region. Myosin A (MyoA), the other class XIV myosin in Plasmodium, has been established as a component of the glideosome complex important in motility and cell invasion, but MyoB is not well characterized. We analyzed the properties of MyoB using three parasite species as follows: Plasmodium falciparum, Plasmodium berghei, and Plasmodium knowlesi. MyoB is expressed in all invasive stages (merozoites, ookinetes, and sporozoites) of the life cycle, and the protein is found in a discrete apical location in these polarized cells. In P. falciparum, MyoB is synthesized very late in schizogony/merogony, and its location in merozoites is distinct from, and anterior to, that of a range of known proteins present in the rhoptries, rhoptry neck or micronemes. Unlike MyoA, MyoB is not associated with glideosome complex proteins, including the MyoA light chain, myosin A tail domain-interacting protein (MTIP). A unique MyoB light chain (MLC-B) was identified that contains a calmodulin-like domain at the C terminus and an extended N-terminal region. MLC-B localizes to the same extreme apical pole in the cell as MyoB, and the two proteins form a complex. We propose that MLC-B is a MyoB-specific light chain, and for the short class XIV myosins that lack a tail region, the atypical myosin light chains may fulfill that role
Impact of Coronary Computerized Tomography Angiography-Derived Plaque Quantification and Machine-Learning Computerized Tomography Fractional Flow Reserve on Adverse Cardiac Outcome
This study investigated the impact of coronary CT angiography (cCTA)-derived plaque markers and machine-learning-based CT-derived fractional flow reserve (CT-FFR) to identify adverse cardiac outcome. Data of 82 patients (60 +/- 11 years, 62% men) who underwent cCTA and invasive coronary angiography (ICA) were analyzed in this single-center retrospective, institutional review board-approved, HIPAA-compliant study. Follow-up was performed to record major adverse cardiac events (MACE). Plaque quantification of lesions responsible for MACE and control lesions was retrospectively performed semiautomatically from cCTA together with machine-learning based CT-FFR. The discriminatory value of plaque markers and CT-FFR to predict MACE was evaluated. After a median follow-up of 18.5 months (interquartile range 11.5 to 26.6 months), MACE was observed in 18 patients (21 %). In a multivariate analysis the following markers were predictors of MACE (odds ratio [OR]): lesion length (OR 1.16, p = 0.018), low-attenuation plaque (= 50% (OR 3.83, p 0.042), and CT-FFR = 50%, plaque markers and CT-FFR = 50% alone (Area under the curve 0.60,
Heterogeneity of Vaginal Microbial Communities within Individualsâż #
Recent culture-independent studies have revealed that a healthy vaginal ecosystem harbors a surprisingly complex assemblage of microorganisms. However, the spatial distribution and composition of vaginal microbial populations have not been investigated using molecular methods. Here, we evaluated site-specific microbial composition within the vaginal ecosystem and examined the influence of sampling technique in detection of the vaginal microbiota. 16S rRNA gene clone libraries were prepared from samples obtained from different locations (cervix, fornix, outer vaginal canal) and by different methods (swabbing, scraping, lavaging) from the vaginal tracts of eight clinically healthy, asymptomatic women. The data reveal that the vaginal microbiota is not homogenous throughout the vaginal tract but differs significantly within an individual with regard to anatomical site and sampling method used. Thus, this study illuminates the complex structure of the vaginal ecosystem and calls for the consideration of microenvironments when sampling vaginal microbiota as a clinical predictor of vaginal health