RELIABILITY OF DIFFERENT METHODS OF DETERMINING INDIVIDUAL INTER-STROKE INTERVALS IN SPRINT KAYAKING

The purpose of this study was to explore the reliability of methods for rapidly determining inter-stroke intervals (ISI) of individual kayakers. One participant performed two 150 m trials at a rate of 80 single-strokes/min. ISI were calculated using two criterion measures, visual identification of blade immersion (VID) and peaks in longitudinal acceleration of the kayak hull (ACC). These were compared to ISI from peak footrest force (FRP), initiation of footrest force (FRT), paddle Y axis rotational velocity (PAP) and paddle X axis acceleration (PAA). Least products regression analysis (LPR) revealed that FRP showed the highest reliability, with no fixed or proportional bias compared to VID or ACC. High ISI during the initial strokes influenced the results of the LPR, as such a framework for investigating the reliability of ISI using LPR is suggested where the initial strokes are removed prior to analysis

Factors related to adolescent drinking in Appalachia

Objectives: To examine the relationships among parental monitoring, perceptions of peer drinking, and adolescent alcohol consumption. Methods: Tenth- and 12thgrade students (N=648) in a rural, Appalachian county were surveyed. Results: A binomial logistic regression revealed a composite of those who had perceptions that many peers drank, low parental monitoring, and no biological male guardian in the home were 8.496 times more likely to have ever been drunk. Other characteristics resulted in lower odds. Conclusions: Parental monitoring and perceptions of peer drinking were important predictors of drinking in this rural sample. Prevention efforts in school and at home should address both variables

Animal community dynamics at senescent and active vents at the 9° N East Pacific Rise after a volcanic eruption

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gollner, S., Govenar, B., Arbizu, P. M., Mullineaux, L. S., Mills, S., Le Bris, N., Weinbauer, M., Shank, T. M., & Bright, M. Animal community dynamics at senescent and active vents at the 9° N East Pacific Rise after a volcanic eruption. Frontiers in Marine Science, 6, (2020): 832, doi:10.3389/fmars.2019.00832.In 2005/2006, a major volcanic eruption buried faunal communities over a large area of the 9°N East Pacific Rise (EPR) vent field. In late 2006, we initiated colonization studies at several types of post eruption vent communities including those that either survived the eruption, re-established after the eruption, or arisen at new sites. Some of these vents were active whereas others appeared senescent. Although the spatial scale of non-paved (surviving) vent communities was small (several m2 compared to several km2 of total paved area), the remnant individuals at surviving active and senescent vent sites may be important for recolonization. A total of 46 meio- and macrofauna species were encountered at non-paved areas with 33 of those species detected were also present at new sites in 2006. The animals living at non-paved areas represent refuge populations that could act as source populations for new vent sites directly after disturbance. Remnants may be especially important for the meiofauna, where many taxa have limited or no larval dispersal. Meiofauna may reach new vent sites predominantly via migration from local refuge areas, where a reproductive and abundant meiofauna is thriving. These findings are important to consider in any potential future deep-sea mining scenario at deep-sea hydrothermal vents. Within our 4-year study period, we regularly observed vent habitats with tubeworm assemblages that became senescent and died, as vent fluid emissions locally stopped at patches within active vent sites. Senescent vents harbored a species rich mix of typical vent species as well as rare yet undescribed species. The senescent vents contributed significantly to diversity at the 9°N EPR with 55 macrofaunal species (11 singletons) and 74 meiofaunal species (19 singletons). Of these 129 species associated with senescent vents, 60 have not been reported from active vents. Tubeworms and other vent megafauna not only act as foundation species when alive but provide habitat also when dead, sustaining abundant and diverse small sized fauna.We received funding from the Austrian FWF (GrantP20190-B17; MB), the U.S. National Science Foundation (OCE-0424953; to LM, D. McGillicuddy, A. Thurnherr, J. Ledwell, and W. Lavelle; and OCE-1356738 to LM), and the European Union Seventh Framework Programme (FP7/2007-2013) under the MIDAS project, Grant Agreement No. 603418. Ifremer and CNRS (France) supported NL cruise participation and sensor developments. BG was supported by a postdoctoral fellowship from the Deep Ocean Exploration Institute at WHOI (United States). TS was supported by the U.S. National Science Foundation (OCE-0327261 to TS and OCE-0937395 to TS and BG)

FRAP Analysis on Red Alga Reveals the Fluorescence Recovery Is Ascribed to Intrinsic Photoprocesses of Phycobilisomes than Large-Scale Diffusion

BACKGROUND: Phycobilisomes (PBsomes) are the extrinsic antenna complexes upon the photosynthetic membranes in red algae and most cyanobacteria. The PBsomes in the cyanobacteria has been proposed to present high lateral mobility on the thylakoid membrane surface. In contrast, direct measurement of PBsome motility in red algae has been lacking so far. METHODOLOGY/PRINCIPAL FINDINGS: In this work, we investigated the dynamics of PBsomes in the unicellular red alga Porphyridium cruentum in vivo and in vitro, using fluorescence recovery after photobleaching (FRAP). We found that part of the fluorescence recovery could be detected in both partially- and wholly-bleached wild-type and mutant F11 (UTEX 637) cells. Such partial fluorescence recovery was also observed in glutaraldehyde-treated and betaine-treated cells in which PBsome diffusion should be restricted by cross-linking effect, as well as in isolated PBsomes immobilized on the glass slide. CONCLUSIONS/SIGNIFICANCE: On the basis of our previous structural results showing the PBsome crowding on the native photosynthetic membrane as well as the present FRAP data, we concluded that the fluorescence recovery observed during FRAP experiment in red algae is mainly ascribed to the intrinsic photoprocesses of the bleached PBsomes in situ, rather than the rapid diffusion of PBsomes on thylakoid membranes in vivo. Furthermore, direct observations of the fluorescence dynamics of phycoerythrins using FRAP demonstrated the energetic decoupling of phycoerythrins in PBsomes against strong excitation light in vivo, which is proposed as a photoprotective mechanism in red algae attributed by the PBsomes in response to excess light energy

Assessing Phototoxicity in a Mammalian Cell Line: How Low Levels of Blue Light Affect Motility in PC3 Cells.

Phototoxicity is a significant constraint for live cell fluorescence microscopy. Excessive excitation light intensities change the homeostasis of the observed cells. Erroneous and misleading conclusions may be the problematic consequence of observing such light-induced pathophysiology. In this study, we assess the effect of blue light, as commonly used for GFP and YFP excitation, on a motile mammalian cell line. Tracking PC3 cells at different light doses and intensities, we show how motility can be used to reliably assess subtle positive and negative effects of illumination. We further show that the effects are a factor of intensity rather than light dose. Mitotic delay was not a sensitive indicator of phototoxicity. For early detection of the effect of blue light, we analysed the expression of genes involved in oxidative stress. This study addresses the need for relatively simple and sensitive methods to establish a dose-response curve for phototoxicity in mammalian cell line models. We conclude with a working model for phototoxicity and recommendations for its assessment

mRNA localization, reaction centre biogenesis and thylakoid membrane targeting in cyanobacteria

The thylakoid membranes of cyanobacteria form a complex intracellular membrane system with a distinctive proteome. The sites of biogenesis of thylakoid proteins remain uncertain, as do the signals that direct thylakoid membrane-integral proteins to the thylakoids rather than to the plasma membrane. Here, we address these questions by using fluorescence in situ hybridization to probe the subcellular location of messenger RNA molecules encoding core subunits of the photosystems in two cyanobacterial species. These mRNAs cluster at thylakoid surfaces mainly adjacent to the central cytoplasm and the nucleoid, in contrast to mRNAs encoding proteins with other locations. Ribosome association influences the distribution of the photosynthetic mRNAs on the thylakoid surface, but thylakoid affinity is retained in the absence of ribosome association. However, thylakoid association is disrupted in a mutant lacking two mRNA-binding proteins, which probably play roles in targeting photosynthetic proteins to the thylakoid membrane

Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone

There is growing interest in mining polymetallic nodules in the abyssal Clarion-Clipperton Zone (CCZ) in the Pacific. Nonetheless, benthic communities in this region remain poorly known. The ABYSSLINE Project is conducting benthic biological baseline surveys for the UK Seabed Resources Ltd. exploration contract area (UK-1) in the CCZ. Using a Remotely Operated Vehicle, we surveyed megafauna at four sites within a 900 km2 stratum in the UK-1 contract area, and at a site ~250 km east of the UK-1 area, allowing us to make the first estimates of abundance and diversity. We distinguished 170 morphotypes within the UK-1 contract area but species-richness estimators suggest this could be as high as 229. Megafaunal abundance averaged 1.48 ind. m−2. Seven of 12 collected metazoan species were new to science, and four belonged to new genera. Approximately half of the morphotypes occurred only on polymetallic nodules. There were weak, but statistically significant, positive correlations between megafaunal and nodule abundance. Eastern-CCZ megafaunal diversity is high relative to two abyssal datasets from other regions, however comparisons with CCZ and DISCOL datasets are problematic given the lack of standardised methods and taxonomy. We postulate that CCZ megafaunal diversity is driven in part by habitat heterogeneity.This open access work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0

An assessment of animal welfare impacts in wild Norway rat (Rattus norvegicus) management

Norway rats (Rattus norvegicus) are considered one of the most significant vertebrate pests globally, because of their impacts on human and animal health. There are legal and moral obligations to minimise the impacts of wildlife management on animal welfare, yet there are few data on the relative welfare impacts of rat trapping and baiting methods used in the UK with which to inform management decisions. Two stakeholder workshops were facilitated to assess the relative welfare impacts of six lethal rat management methods using a welfare assessment model. Fifteen stakeholders including experts in wildlife management, rodent management, rodent biology, animal welfare science, and veterinary science and medicine, participated. The greatest welfare impacts were associated with three baiting methods, anticoagulants, cholecalciferol and non-toxic cellulose baits (severe to extreme impact for days), and with capture on a glue trap (extreme for hours) with concussive killing (mild to moderate for seconds to minutes); these methods should be considered last resorts from a welfare perspective. Lower impacts were associated with cage trapping (moderate to severe for hours) with concussive killing (moderate for minutes). The impact of snap trapping was highly variable (no impact to extreme for seconds to minutes). Snap traps should be regulated and tested to identify those that cause rapid unconsciousness; such traps might represent the most welfare-friendly option assessed for killing rats. Our results can be used to integrate consideration of rat welfare alongside other factors, including cost, efficacy, safety, non-target animal welfare and public acceptability when selecting management methods. We also highlight ways of reducing welfare impacts and areas where more data are needed

Expression of excess receptors and negative feedback control of signal pathways are required for rapid activation and prompt cessation of signal transduction

Cellular signal transduction is initiated by the binding of extracellular ligands to membrane receptors. Receptors are often expressed in excess, and cells are activated when a small number of receptors bind ligands. Intracellular signal proteins are act