19,747 research outputs found
The molecular cloning and characterisation of cDNA coding for the alpha subunit of the acetylcholine receptor
The published version of this article is available at Oxford Journals in Nucleic Acids Research at
http://nar.oxfordjournals.org/content/10/19/5809.full.pdf+htmlA rare cDNA coding for most of the α subunit of the Torpedo nicotinic acetylcholine receptor has been cloned into bacteria. The use of a mismatched oligonucleotide primer of reverse transcriptase facilitated the design of an efficient, specific probe for recombinant bacteria. DNA sequence analysis has enabled the elucidation of a large part of the polypeptide primary sequence which is discussed in relation to its acetylcholine binding activity and the location of receptor within the plasma membrane.
When used as a radioactive probe, the cloned cDNA binds specifically to a single Torpedo mRNA species of about 2350 nucleotides in length but fails to show significant cross-hybridisation with a subunit mRNA extracted from cat muscle
Future apprenticeships in England: mediating forces and factors in the new model
Apprenticeship systems across the globe are having to adapt to changing international economic and social trends. England is no exception. This article examines the latest model of apprenticeship in England from the perspective of the ‘mediators’ who work at local and regional level with employers to construct and deliver the majority of current apprenticeships. The role of these actors is examined through a conceptual framework analysing different forms of mediation in the context of ‘the modern expanded state’. Their views were collected through 27 focus groups in nine regions of England in Spring 2016 and involving over 100 participants. These data suggest that the new apprenticeship model faces a number of challenges; notably how to engage small and medium-sized enterprises and how to better support the mobility and progression of apprentices. Participants advocated the development of regional and local networks comprising employers, FE colleges and other providers, HEIs and local government, as ways of sustaining the ‘apprenticeship market’, providing learner progression routes and stimulating employer demand for skills. The article concludes by arguing that these types of networks might develop into ‘high skills ecosystems’ providing certain conditions are met
The Area-Based Review in London: two logics of reform
This is the first report of the research project on Area-Based Reviews in London. Based on interviews with a range of stakeholders in 2016, it captures perceptions of the early stages of the review process. From the evidence collected so far, the report concludes that the Area-Based Reviews contain two related logics - Logic A focused on college financial viability and Logic B focused on developing vocational skills across an Area. Presently, Logic A dominates Logic
A unique dual activity amino acid hydroxylase in Toxoplasma gondii
The genome of the protozoan parasite Toxoplasma gondii was found to contain two genes encoding tyrosine hydroxylase; that produces L-DOPA. The encoded enzymes metabolize phenylalanine as well as tyrosine with substrate preference for tyrosine. Thus the enzymes catabolize phenylalanine to tyrosine and tyrosine to L-DOPA. The catalytic domain descriptive of this class of enzymes is conserved with the parasite enzyme and exhibits similar kinetic properties to metazoan tyrosine hydroxylases, but contains a unique N-terminal extension with a signal sequence motif. One of the genes, TgAaaH1, is constitutively expressed while the other gene, TgAaaH2, is induced during formation of the bradyzoites of the cyst stages of the life cycle. This is the first description of an aromatic amino acid hydroxylase in an apicomplexan parasite. Extensive searching of apicomplexan genome sequences revealed an ortholog in Neospora caninum but not in Eimeria, Cryptosporidium, Theileria, or Plasmodium. Possible role(s) of these bi-functional enzymes during host infection are discussed. © 2009 Gaskell et al
Investigation of the use of inertial sensing equipment for the measurement of hip flexion and pelvic rotation in horse riders
Equestrian sports report three to five times higher incidence rates for lower back pain than that of the general population, with hip flexion angles of 50-60° suggested as a causal factor. Inertial motion capture technology enables dynamic measurement of rider kinematics but data extraction is time-consuming. The aim of this study was to develop a software tool to automate the process of extracting biomechanical data from the XsensTM MVN (MoCap) system to investigate postural changes in riders, comparing static position at halt with dynamic position during the sit phase of rising trot. The software was found to be efficient, reducing data extraction time by 97% when used with a sample of 16 riders. Good correlation was found between hip flexion and pelvic anterior-posterior rotation and between halt and trot but with significantly greater values of hip flexion and pelvic anterior rotation in trot. No riders showed hip flexion >50° at halt but 11 riders (69%) showed hip flexion >50° during the sit phase of rising trot, indicating that dynamic assessment is important when considering rider postural faults that may put them at risk of back injury.
Keywords: Hip flexion, Horse rider, Inertial sensor, Motion capture, Pelvic rotatio
Investigation of Non-Stable Processes in Close Binary Ry Scuti
We present results of reanalysis of old electrophotometric data of early type
close binary system RY Scuti obtained at the Abastumani Astrophysical
Observatory, Georgia, during 1972-1990 years and at the Maidanak Observatory,
Uzbekistan, during 1979-1991 years. It is revealed non-stable processes in RY
Sct from period to period, from month to month and from year to year. This
variation consists from the hundredths up to the tenths of a magnitude.
Furthermore, periodical changes in the system's light are displayed near the
first maximum on timescales of a few years. That is of great interest with
regard to some similar variations seen in luminous blue variable (LBV) stars.
This also could be closely related to the question of why RY Sct ejected its
nebula.Comment: 11 pages, 6 figures, 2 table
Antibacterial Activities of Lactic Acid Bacteria Isolated from Selected Vegetables Grown in Nigeria: A Preliminary Report
Members of lactic acid bacteria (LAB) are known probiotics and have been reported to have antimicrobial properties. Although various researchers have documented the isolation of these bacteria from fruits and vegetables, studies on LAB associated with lettuce, cucumber and cabbage are limited and non-existing in Nigeria. This study was designed to assess lettuce, cucumber and cabbage as potential sources of LAB and investigate the actions of their bacterial cell supernatants (BCS) on some pathogenic bacteria. Using standard microbiological methods, isolated LAB were identified to species level with API 50 CH kits (Biomerieux, France). Cell free supernatants (CFS) from de Man Rogosa Sharpe (MRS) broth cultures of the LAB strains were used to challenge Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 12900 and Proteus penneri ATCC 13315 by agar well diffusion method. The control consisted of the sterile MRS broth subjected to the same growth conditions as LAB broth cultures. A total of four lactic acid bacteria were isolated as follows: Pediococcus pentosaceus 2 from cucumber, Lactobacillus cellobiosus from cabbage, Lactobacillus salivarius and Lactobacillus plantarum 1 from lettuce. Pediococcus pentosaceus 2 and L. salivarius showed inhibitory effects on all the standard strains tested while L. plantarum 1 showed no inhibitory activity against E. faecalis and E. coli. Lactobacillus cellobiosus showed inhibition against all except P. penneri. Although, the molecular characterisation and probiotic potentials of these LAB strains are being investigated in an on-going study, we presumed these vegetables are prospective sources of the bacteria in Nigeria and therefore the need to extensively investigate the vegetables and other related vegetables becomes imperative
A hitchhikers guide to the Galápagos: co-phylogeography of Galápagos mockingbirds and their parasites
Background: Parasites are evolutionary hitchhikers whose phylogenies often track the evolutionary history of their hosts. Incongruence in the evolutionary history of closely associated lineages can be explained through a variety of possible events including host switching and host independent speciation. However, in recently diverged lineages stochastic population processes, such as retention of ancestral polymorphism or secondary contact, can also explain discordant genealogies, even in fully co-speciating taxa. The relatively simple biogeographic arrangement of the Galapagos archipelago, compared with mainland biomes, provides a framework to identify stochastic and evolutionary informative components of genealogic data in these recently diverged organisms. Results: Mitochondrial DNA sequences were obtained for four species of Galapagos mockingbirds and three sympatric species of ectoparasites - two louse and one mite species. These data were complemented with nuclear EF1 alpha sequences in selected samples of parasites and with information from microsatellite loci in the mockingbirds. Mitochondrial sequence data revealed differences in population genetic diversity between all taxa and varying degrees of topological congruence between host and parasite lineages. A very low level of genetic variability and lack of congruence was found in one of the louse parasites, which was excluded from subsequent joint analysis of mitochondrial data. The reconciled multi-species tree obtained from the analysis is congruent with both the nuclear data and the geological history of the islands. Conclusions: The gene genealogies of Galapagos mockingbirds and two of their ectoparasites show strong phylogeographic correlations, with instances of incongruence mostly explained by ancestral genetic polymorphism. A third parasite genealogy shows low levels of genetic diversity and little evidence of co-phylogeny with their hosts. These differences can mostly be explained by variation in life-history characteristics, primarily host specificity and dispersal capabilities. We show that pooling genetic data from organisms living in close ecological association reveals a more accurate phylogeographic history for these taxa. Our results have implications for the conservation and taxonomy of Galapagos mockingbirds and their parasites
Temperature effects on export production in the open ocean
A pelagic food web model was formulated with the goal of developing a quantitative understanding of the relationship between total production, export production, and environmental variables in marine ecosystems. The model assumes that primary production is partitioned through both large and small phytoplankton and that the food web adjusts to changes in the rate of allochthonous nutrient inputs in a way that maximizes stability, i.e., the ability of the system to return to steady state following a perturbation. The results of the modeling exercise indicate that ef ratios, defined as new production/total production = export production/total production, are relatively insensitive to total production rates at temperatures greater than ∼25°C and lie in the range 0.1‐0.2. At moderate to high total production rates, ef ratios are insensitive to total production and negatively correlated with temperature. The maximum ef ratios are ∼0.67 at high rates of production and temperatures of 0°−10°C. At temperatures less than ∼20°C, there is a transition from low ef ratios to relatively high ef ratios as total production increases from low to moderate values. This transition accounts for the hyperbolic relationship often presumed to exist between ef ratios and total production. At low rates of production the model predicts a negative correlation between production and ef ratios, a result consistent with data collected at station ALOHA (22°45′N, 158°W) in the North Pacific subtropical gyre. The predictions of the model are in excellent agreement with results reported from the Joint Global Ocean Flux Study (JGOFS) and from other field work. In these studies, there is virtually no correlation between total production and ef ratios, but temperature alone accounts for 86% of the variance in the ef ratios. Model predictions of the absolute and relative abundance of autotrophic and heterotrophic microorganisms are in excellent agreement with data reported from field studies. Combining the ef ratio model with estimates of ocean temperature and photosynthetic rates derived from satellite data indicates that export production on a global scale is ∼20% of net photosynthesis. The results of the model have important implications for the impact of climate change on export production, particularly with respect to temperature effects
An integrated discrete event simulation and particle swarm optimisation model for optimising efficiency of cancer diagnosis pathways
The National Health Service (NHS) constitution sets out minimum standards for rights of access of patients to NHS services. The ‘Faster Diagnosis Standard’ (FDS) states that 75% of patients should be told whether they have a diagnosis of cancer or not within 28 days of an urgent GP referral. Timely diagnosis and treatment lead to improved outcomes for cancer patients, however, compliance with these standards has recently been challenged, particularly in the context of operational pressures and resource constraints relating to the COVID-19 pandemic. In order to minimise diagnostic delays, the National Physical Laboratory in collaboration with the Royal Free London (RFL) NHS Foundation Trust address this problem by treating it as a formal resource optimisation, aiming to minimise the number of patients who breach the FDS. We use discrete event simulation and particle swarm optimisation to identify areas for improving the efficiency of cancer diagnosis at the RFL. We highlight capacity-demand mismatches in the current cancer diagnosis pathways at the RFL, including imaging and endoscopy investigations. This is due to the volume of patients requiring these investigations to meet the 28-day FDS target. We find that increasing resources in one area alone does not fully solve the problem. By looking at the system as a whole we identify areas for improvement which will have system-wide impact even though individually they do not necessarily seem significant. The outcomes and impact of this project have the potential to make a valuable impact on shaping future hospital activity
- …