Cardiac and Metabolic Physiology of Early Larval Zebrafish (Danio rerio) Reflects Parental Swimming Stamina

Swimming stamina in adult fish is heritable, it is unknown if inherited traits that support enhanced swimming stamina in offspring appear only in juveniles and/or adults, or if these traits actually appear earlier in the morphologically quite different larvae. To answer this question, mature adult zebrafish (Danio rerio) were subjected to a swimming performance test that allowed separation into low swimming stamina or high swimming stamina groups. Adults were then bred within their own performance groups. Larval offspring from each of the two groups, designated high (LHSD) and low stamina-derived larvae (LLSD), were then reared at 27°C in aerated water (21% O2). Routine (fH,r) and active (fH,a) heart rate, and routine (Ṁo2,r) and active (Ṁo2,a) mass-specific oxygen consumption were recorded from 5 days post fertilization (dpf) through 21 dpf, and gross cost of transport and factorial aerobic metabolic scope were derived from Ṁo2 measurements. Heart rate generally ranged between 150 and 225 bpm in both LHSD and LLSD populations. However, significant (P < 0.05) differences existed between the LLSD and LHSD populations at 5 and 14 dpf in fH,r and at days 10 and 15 dpf in fH,a. Ṁo2,r was 0.04–0.32 μmol mg−1 h−1, while Ṁo2,a was 0.2–1.2 μmol mg−1 h−1. Significant (P < 0.05) differences between the LLSD and LHSD populations in Ṁo2,r occurred at 7, 10, and 21 dpf and in Ṁo2,a at 7 dpf. Gross cost of transport was ∼6–10 μmol O2·μg−1 m−1 at 5 dpf, peaking at 14–19 μmol O2 μg−1 m−1 at 7–10 dpf, before falling again to 5–6 μmol O2 μg−1 m−1 at 21 dpf, with gross cost of transport significantly higher in the LLSD population at 7 dpf. Collectively, these data indicate that inherited physiological differences known to contribute to enhanced stamina in adult parents also appear in their larval offspring well before attainment of juvenile or adult features

Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes

The dark electrocatalytic and light photocathodic hydrogen evolution properties of Ni, Ni–Mo alloys, and Pt on Si electrodes have been measured, to assess the viability of earth-abundant electrocatalysts for integrated, semiconductor coupled fuel formation. In the dark, the activities of these catalysts deposited on degenerately doped p^+-Si electrodes increased in the order Ni < Ni–Mo ≤ Pt. Ni–Mo deposited on degenerately doped Si microwires exhibited activity that was very similar to that of Pt deposited by metal evaporation on planar Si electrodes. Under 100 mW cm^(−2) of Air Mass 1.5 solar simulation, the energy conversion efficiencies of p-type Si/catalyst photoelectrodes ranged from 0.2–1%, and increased in the order Ni ≈ Ni–Mo < Pt, due to somewhat lower photovoltages and photocurrents for p-Si/Ni–Mo relative to p-Si/Ni and p-Si/Pt photoelectrodes. Deposition of the catalysts onto microwire arrays resulted in higher apparent catalytic activities and similar photoelectrode efficiencies than were observed on planar p-Si photocathodes, despite lower light absorption by p-Si in the microwire structures

Workplace parking levies: the answer to funding large scale local transport improvements in the UK?

Despite positive experiences in Australia of utilising area wide workplace parking place charges to pay for public transport improvement, only one UK local authority, to date, Nottingham City Council has chosen to implement a Work Place Parking Levy scheme (WPL). This scheme intends to allocate the revenue raised to fund (amongst other things) two new tram lines. Acceptance by the public and the business community are seen as key barriers to implementing a WPL. The two major criticisms of the Nottingham scheme prior to its implementation were that a WPL would discourage business investment and thus damage the economy while its intended impact on traffic congestion would be minimal. Therefore a detailed assessment of the Nottingham WPL scheme’s performance is essential in order to facilitate transferability of this approach to other UK and European Cities and thus bring WPL into the mainstream for funding transport improvements. This paper outlines the barriers to implementation of the Nottingham WPL scheme, and the rationale behind the chosen use of revenue and how the scheme’s performance will be evaluated as a transport demand management measure, as well as some initial performance monitoring data following the first year of operation. The results to date are discussed with a view to identifying any early indications as to whether traffic congestion and business investment has been impacted by the scheme’s introduction

Evidence for Divisome Localization Mechanisms Independent of the Min System and SlmA in Escherichia coli

Cell division in Escherichia coli starts with assembly of FtsZ protofilaments into a ring-like structure, the Z-ring. Positioning of the Z-ring at midcell is thought to be coordinated by two regulatory systems, nucleoid occlusion and the Min system. In E. coli, nucleoid occlusion is mediated by the SlmA proteins. Here, we address the question of whether there are additional positioning systems that are capable of localizing the E. coli divisome with respect to the cell center. Using quantitative fluorescence imaging we show that slow growing cells lacking functional Min and SlmA nucleoid occlusion systems continue to divide preferentially at midcell. We find that the initial Z-ring assembly occurs over the center of the nucleoid instead of nucleoid-free regions under these conditions. We determine that Z-ring formation begins shortly after the arrival of the Ter macrodomain at the nucleoid center. Removal of either the MatP, ZapB, or ZapA proteins significantly affects the accuracy and precision of Z-ring positioning relative to the nucleoid center in these cells in accordance with the idea that these proteins link the Ter macrodomain and the Z-ring. Interestingly, even in the absence of Min, SlmA, and the putative Ter macrodomain – Z-ring link, there remains a weak midcell positioning bias for the Z-ring. Our work demonstrates that additional Z-ring localization systems are present in E. colithan are known currently. In particular, we identify that the Ter macrodomain acts as a landmark for the Z-ring in the presence of MatP, ZapB and ZapA proteins

The Effect of DNA Structure on the Catalytic Efficiency and Fidelity of Human DNA Polymerase β on Templates with Platinum-DNA Adducts

DNA adducts formed by platinum-based anticancer drugs interfere with DNA replication. The carrier ligand of the platinum compound is likely to affect the conformation of the Pt-DNA adducts. In addition, the conformation of the adduct can also change upon binding of damaged DNA to the active site of DNA polymerase. From the crystal structures of pol beta ternary complexes it is evident that undamaged gapped and primed single-stranded (non-gapped) DNA templates exist in very different conformations when bound to pol beta. Therefore, one might expect that the constraints imposed on the damaged templates by binding to the polymerase active site should also affect the conformation of the Pt-DNA adducts and their ability to inhibit DNA replication. In support of this hypothesis we have found that the efficiency, carrier ligand specificity, site of discrimination (3'-G versus 5'-G of the Pt-GG adducts), and fidelity of translesion synthesis past Pt-DNA adducts by pol beta are strongly affected by the structure of the DNA template. Previous studies have suggested that the conformation of Pt-DNA adducts may be affected by the sequence context of the adduct. In support of this hypothesis, our data show that sequence context affects the efficiency, fidelity, and pattern of misincorporation by pol beta

Deepwater Horizon Oil Spill as a Case Study for Interdisciplinary Cooperation within Developmental Biology, Environmental Sciences and Physiology

This article makes the argument for interdisciplinary teams that bring together scientists with different specialties as an efficient way--and perhaps the only way--to unravel highly complex biological effects of marine oil spills

Extensive error in the number of genes inferred from draft genome assemblies

Current sequencing methods produce large amounts of data, but genome assemblies based on these data are often woefully incomplete. These incomplete and error-filled assemblies result in many annotation errors, especially in the number of genes present in a genome. In this paper we investigate the magnitude of the problem, both in terms of total gene number and the number of copies of genes in specific families. To do this, we compare multiple draft assemblies against higher-quality versions of the same genomes, using several new assemblies of the chicken genome based on both traditional and next-generation sequencing technologies, as well as published draft assemblies of chimpanzee. We find that upwards of 40% of all gene families are inferred to have the wrong number of genes in draft assemblies, and that these incorrect assemblies both add and subtract genes. Using simulated genome assemblies of Drosophila melanogaster, we find that the major cause of increased gene numbers in draft genomes is the fragmentation of genes onto multiple individual contigs. Finally, we demonstrate the usefulness of RNA-Seq in improving the gene annotation of draft assemblies, largely by connecting genes that have been fragmented in the assembly process