3,094 research outputs found
Clustering and dynamics of cytochrome bd-I complexes in the Escherichia coli plasma membrane in vivo.
No full textThe cytochrome bd-I complex of Escherichia coli is a respiratory terminal oxidase and an integral component of the cytoplasmic membrane. As with other respiratory components, the organization and dynamics of this complex in living membranes is unknown. We set out to visualize the distribution and dynamics of this complex in vivo. By exchanging cydB for cydB-gfpgcn4 on the E. coli chromosome, we produced a strain (YTL01) that expresses functional GFP-tagged cytochrome bd-I terminal oxidase complexes under wild-type genetic control. We imaged live YTL01 cells using video-rate epifluorescence and total internal reflection fluorescence (TIRF) microscopy in combination with fluorescence recovery after photobleaching (FRAP) and saw mobile spots of GFP fluorescence in plasma membranes. Numbers of GFP molecules per spot were quantified by step-wise photobleaching giving a broad distribution with a mean of approximately 76, indicating that cytochrome bd-I is concentrated in mobile patches in the E. coli plasma membrane. We hypothesize that respiration occurs in mobile membrane patches which we call 'respirazones'
The Amperima Event: Analysis of community change in the abyssal NE Atlantic Ocean [PhD Thesis]
No full textCytochrome bd displays significant quinol peroxidase activity
No full textCytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem
In situ observations of predatory feeding behaviour of the galatheid squat lobster Munida sarsi using a remotely operated vehicle
No full textDuring remotely operated vehicle operations on the UK continental shelf to the west of Shetland (60degrees6\u27N 4degrees4\u27W) at a depth of 400 in, Munida sarsi, a common benthic crustacean was observed actively preying on the northern krill Meganyctiphanes norvegica. Video footage shows the individual using its chelipeds to catch prey items as they swarm around its burrow. These initial observations indicate that predation forms a new feeding strategy for a species previously believed to be an active scavenger
BD Rhapsody WTA AbSeq Analysis
No full text<p>Dataset and codes for BD Rhapsody single cell analysis system.</p>
<p>Disclaimer: The set of codes are optimised for the associated dataset only. For detailed understanding of the analysis procesure, please refer to https://github.com/INGEN-HOPE/Single-Cell-Multi-Omics-Data-Analysis-for-BD-Rhapsody. For any kind queries, please refer to the corresponding author, or post your query on our GitHub page.</p>
Growth of number of periodic orbits of one family of skew product maps
No full textIn this article we introduce a one-parameter family of skew product (Gt)t ∈ [−ε, ε] maps exhibiting a heterodimensional cycle such that the number of isolated periodic orbits inside it has not super-exponential growth. The dynamics in the central direction of the maps Gt is described by a one-parameter family of system of iterated functions.This work is part of the PhD thesis of the author, under the supervision
of Lorenzo Diaz and Jorge Rocha. The author thanks Professors Lorenzo Diaz and Jorge Rocha, for
having proposed this topic, by the stimulating conversations, the guidance and useful suggestions.
This research was funded by by the Portuguese government through the FCT (Fundação para a
Ciência e a Tecnologia) under the project PTDC/MAT/099493/2008. The author was supported by
the grants SFRH/BD/27674/2006 and SFRH/BD/49735/2009 of FCT.info:eu-repo/semantics/publishedVersio
Community influences on E/BD student achievement
No full textNo Child Left Behind has mandated that all students reach proficiency by 2014. This mandate places special emphasis on the performance of special education students. The purpose of this study is to use social theory to understand the factors that explain the achievement of emotionally or behaviorally disordered (E/BD) students. Results suggest a differential effect of neighborhood composition on the development of social ties for Black and White E/BD students. The author argues for an increased awareness of the development of within-school social ties that integrate groups. © 2008 Corwin Press, Inc.link_to_subscribed_fulltex
Long-term change in a North Sea inshore fish assemblage between 1899–1913 and 2018–2019
Full text link\ua9 G. L. Hunt, B. D. Wigham, N. V. C. Poulin and The Crown 2024.Marine communities have been impacted by human activities for centuries, yet historical data are rarely incorporated into modern conservation efforts and restoration targets. For inshore waters, survey data sets are typically lacking because they extend back by only a few decades, despite their ecological significance as nursery grounds for many fish species. We investigated long-term change in a demersal fish assemblage from inshore waters of the Northumberland coast (UK). We collated unique historical data (1899–1913) that were sampled using a wooden beam trawl during scientific trawling investigations, shortly after the onset of widespread mechanised trawling in the North Sea. Twelve decades later (2018–2019), we re-surveyed the same bays using a modern otter trawl. The results revealed marked declines in the abundance and diversity of the entire fish and flatfish assemblage as well as among individual species. Elasmobranchs and formerly abundant species such as grey gurnard Eutrigla gurnardus were completely absent in contemporary surveys, while dab Limanda limanda and plaice Pleuronectes platessa were the most dominant species in both periods. Changes were also detected in the size distributions of the entire fish and flatfish assemblages, with proportionally fewer large individuals recorded in contemporary surveys. These findings suggest that over a century of trawling and climate change, combined with pollution, habitat alteration and increased predation risk are likely contributors to changes in the inshore fish assemblage. This work provides further evidence of long-term decline in North Sea inshore waters and offers an invaluable benchmark for improving coastal ecosystem status
Comparing the delivery to the hair bulb of two fluorescent molecules of distinct hydrophilicities by different nanoparticles and a serum formulation
Full text linkThe follicular route is an important drug penetration pathway in any topical application, either concerning dermatological and cosmetic skin treatments or any transdermal administration regimen. Efficient transport into follicles will depend on drug inherent properties but also on the chosen vehicle. The main study goal was to compare several systems for the delivery to the hair bulb of two fluorescent molecules of different water affinities: the hydrophobic Nile Red and the quite similar but hydrophilic Nile Blue. Three common nanoparticle types were compared in terms of encapsulation efficiency and stability: liposomes, ethosomes and polymeric nanoparticles. A liquid serum-like formulation was also developed, adjusting the final ethanol amount to the type of dye to be solubilized. Then, this formulation and the nanoparticle systems that successfully passed characterization and stability stages were further studied on their ability to reach the bulb. The serum formulation was able to deliver, both drug models, to deeper follicular regions than nanoparticles. Attending to the envisioned zone target of the follicle, the simplest approach proved to be the best choice from all the systems tested in this work. Nonetheless, nanocarriers and the inherent complexity of their manufacturing processes may be justified under very specific requirements.The author Cristiana Costa would like to acknowledge his PhD scholarship funded by Portuguese
Foundation for Science and Technology (FCT) (SFRH/BD/139522/2018). The author Bruno
Fernandes would like to acknowledge his PhD scholarship funded by FCT (SFRH/BD/131824/2017).
The author Diana Guimarães would like to acknowledge his PhD scholarship funded by FCT
(SFRH/BD/140321/2018). This study was supported by the FCT under the scope of BioTecNorte
operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund
under the scope of Norte2020 – Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio
In situ quantification of bioturbation using time-lapse fluorescent sediment profile imaging (f-SPI), luminophore tracers and model simulation
No full textIn order to link actual biological data on bioturbation to the abstract parameters in bioturbation models, high-resolution data on the frequency and lengths of particle displacements are required. The temporal variation in bioturbation for a subtidal macrofaunal assemblage was studied non-invasively and in situ using an optically modified fluorescence sensitive time-lapse sediment profile imaging camera (f-SPI), fluorescent-dyed sediment particles (luminophores) and mathematical modelling. This combined approach allowed tracer particles to be non-invasively tracked and their displacements monitored at an unprecedented spatial (78 µm) and temporal (every 10 min) resolution for extended periods of time (16 h). The redistribution of luminophores was digitally acquired from sequential images and compared to model predictions, with particle transport modelled as (1) a diffusive process, allowing the biodiffusion coefficient, Db, to be estimated, and (2) a non-local process, allowing a reworking activity constant, a, to be calculated. Model predictions of luminophore particle transport for the final image of the f-SPI sequence gave: Db = 1.26 × 102 cm2 yr-1; a = 5.23 × 10-2 cm-1 yr-1. Discrete values of a fluctuated widely throughout the sequence and allowed discrete bioturbation events to be identified. Time-lapse movie sequences revealed that most of the bioturbation observed during the deployment could be directly attributed to the behaviour of the brachyuran crab Hyas araneus. Our findings demonstrate that f-SPI provides a rapid and non-invasive means to visualise and quantify, in situ, the extent and influence of discrete infaunal bioturbation events on particle mixing. This technique provides detailed information on the spatial and temporal resolution of such bioturbation events, which could significantly improve existing models of bioturbation
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