6,882 research outputs found
Comparative phylogenetic analysis of vitellogenin in species of cyst and root-knot nematodes
© KONINKLIJKE BRILL NV, LEIDEN, 2023. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1163/15685411-bja10232Plant-parasitic nematodes (PPN) are an economically important group of crop pests and are oviparous animals; all nutrients required to develop and ensure the survival of their unhatched progeny need to be deposited within the egg, including proteins. The most abundant protein deposited is vitellin, formed of a precursor protein vitellogenin, which has roles in transporting lipids, providing amino acids and influencing post-embryonic development. The genes encoding vitellogenin have been well studied in Caenorhabditis elegans, but little is known about vitellogenin in PPN. Using the vitellogenin gene sequences from C. elegans, homologous sequences in the genomes of some economically important cyst and root-knot nematodes were identified and hypothetical vitellogenin genes were predicted. Protein domains were then determined. Sequences were aligned using MUSCLE and then used to construct phylogenetic trees using the maximum likelihood method. With the availability of genomic data and use of online local alignment tools, the vitellogenin encoding genes from C. elegans could be aligned to PPN genomes. All predicted genes contained the same protein domains as C. elegans; Vitellogenin-N, vitellogenin open beta-sheet and von Willebrand factor domain type D. The constructed phylogenetic tree clustered the species into four groups: root-knot nematodes, two cyst nematode groups and Caenorhabditis species. By determining the hypothetical vitellogenin genes in PPN and inferring their relationships, this could form a potential basis to understand further the role of vitellogenin in cyst and root-knot nematodes.Peer reviewe
An exploratory investigation into strategic groups and strategic blocks as an explanation for patterns of rivalry in the international airline industry
Strategic groups and strategic blocks offer alternative approaches to understanding patterns of intraindustry rivalry. Strategic groups have traditionally been conceptualised in terms of scope and resource commitments, whereas strategic block theory clusters firms together on the basis of the density of interorganisational linkages. This paper empirically tests the relative utility of the concepts of strategic groups and strategic blocks in the interpretation of patterns of rivalry across a number of international airline routes, ex-Australia. The findings suggest that both conceptual tools offer insight into the patterns of rivalry evidenced in the industry, however the number of strategic groups present on each route served as the better predictor of the degree of rivalry.Pag
Galaxies as Fluctuations in the Ionizing Background Radiation at Low Redshift
Some Lyman continuum photons are likely to escape from most galaxies, and
these can play an important role in ionizing gas around and between galaxies,
including gas that gives rise to Lyman alpha absorption. Thus the gas
surrounding galaxies and in the intergalactic medium will be exposed to varying
amounts of ionizing radiation depending upon the distances, orientations, and
luminosities of any nearby galaxies. The ionizing background can be
recalculated at any point within a simulation by adding the flux from the
galaxies to a uniform quasar contribution. Normal galaxies are found to almost
always make some contribution to the ionizing background radiation at redshift
zero, as seen by absorbers and at random points in space. Assuming that about 2
percent of ionizing photons escape from a galaxy like the Milky Way, we find
that normal galaxies make a contribution of at least 30 to 40 percent of the
assumed quasar background. Lyman alpha absorbers with a wide range of neutral
column densities are found to be exposed to a wide range of ionization rates,
although the distribution of photoionization rates for absorbers is found to be
strongly peaked. On average, less highly ionized absorbers are found to arise
farther from luminous galaxies, while local fluctuations in the ionization rate
are seen around galaxies having a wide range of properties.Comment: 10 pages, 8 figures, references added, clarified explanation of first
two equation
Evaluation of injury to Saccharomyces rouxii YSa40 cells in low water activity/pH glycerol/CPB stress system
Mid-exponential phase Saccharomyces rouxii YSa40 cells subsequently stressed at low a w/pH in the 0.64 a w/pH 3.5 glycerol/CPB system became injured. Such injury was detected by the loss of ability of the stressed population to form colonies on secondary-stress plating medium (glycerol/BM agar at 0.94 a w/pH 3.5 (lactic acid)) while colony forming ability on secondary non-stress plating medium (sugars/BM agar at 0.94 a w/pH 3.5 (lactic) was unaffected. The injury was shown to be due to sensitivity to glycerol/lactic acid. Results of the present study will be useful for achieving complete decontamination of 'Intermediate Moisture Foods' against xerotolerant molds and yeast
An optimized multiplex flow cytometry protocol for the analysis of intracellular signaling in peripheral blood mononuclear cells
AbstractPhosphoflow cytometry is increasingly being used as a tool for the discovery of biomarkers used in the treatment and monitoring of disease and therapy. The ability to measure numerous phospho-protein targets simultaneously at a single cell level accurately and rapidly provides significant advantages over other methods. We here discuss important considerations required to successfully implement these methods. Three different blood collection tubes (lithium-heparin tubes, CPT with sodium citrate and CPT with sodium heparin) were evaluated, with PBMC isolated through lithium-heparin tubes/lymphoprep displaying reduced basal and increased stimulation induced phosphorylation compared to the other two methods. Further, we provide a protocol outlining an 8 color assay developed for the study of intracellular signaling in peripheral blood mononuclear cells. The assay allows for the quantitative measurement of the phospho-proteins ERK1/2, NF-κB p65, Stat1 (Y701), Stat1 (S727), Stat3 (Y705), Stat3 (S727), Stat4 (Y693), p38 and Stat5 (Y694), as well as the identification of T cells, B cells, natural killer cells and monocytes. The assay additionally incorporates fluorescent cell barcoding, reducing assay costs and increasing throughput while increasing data robustness. Inter-assay precision was assessed over a month long period for all experimental variables (phospho-protein measured, cell type and stimulant). Coefficient of variations (CVs) calculated from process triplicates of normalized median fluorescence intensity (MFI) of the phospho-proteins displayed median CVs under 10% when grouped according to cell type, stimulation agent and phospho-protein measured, while the CV for each triplicate did not exceed 20%
The Planetary Nebulae Population in the Nuclear Regions of M31: the SAURON view
Following a first study of the central regions of M32 that illustrated the
power of integral-field spectroscopy (IFS) in detecting and measuring the [O
III]{\lambda}5007 emission of PNe against a strong stellar background, we turn
to the very nuclear PN population of M31, within 80 pc of its centre. We show
that PNe can also be found in the presence of emission from diffuse gas and
further illustrate the excellent sensitivity of IFS in detecting extragalactic
PNe through a comparison with narrowband images obtained with the Hubble Space
Telescope. We find the nuclear PNe population of M31 is only marginally
consistent with the generally adopted form of the PNe luminosity function
(PNLF). In particular, this is due to a lack of PNe with absolute magnitude
M5007 brighter than -3, which would only result from a rather unfortunate draw
from such a model PNLF. We suggest that the observed lack of bright PNe in the
nuclear regions of M31 is due to a horizontal-branch population that is more
tilted toward less massive and hotter He-burning stars, so that its progeny
consists mostly of UV-bright stars that fail to climb back up the asymptotic
giant branch (AGB) and only of few, if any, bright PNe powered by central
post-AGB stars. These results are also consistent with recent reports on a
dearth of bright post-AGB stars towards the nucleus of M31, and lend further
support to the idea that the metallicity of a stellar population has an impact
on the way the horizontal branch is populated and to the loose anticorrelation
between the strength of the UV-upturn and the specific number of PNe that is
observed in early-type galaxies. Finally, our investigation also serves to
stress the importance of considering the same spatial scales when comparing the
PNe population of galaxies with the properties of their stellar populations.Comment: 11 pages, 10 figures, accepted for publication on Monthly Notices of
the Royal Astronomical Societ
Strongly correlating liquids and their isomorphs
This paper summarizes the properties of strongly correlating liquids, i.e.,
liquids with strong correlations between virial and potential energy
equilibrium fluctuations at constant volume. We proceed to focus on the
experimental predictions for strongly correlating glass-forming liquids. These
predictions include i) density scaling, ii) isochronal superposition, iii) that
there is a single function from which all frequency-dependent viscoelastic
response functions may be calculated, iv) that strongly correlating liquids are
approximately single-parameter liquids with close to unity Prigogine-Defay
ratio, and v) that the fictive temperature initially decreases for an isobaric
temperature up jump. The "isomorph filter", which allows one to test for
universality of theories for the non-Arrhenius temperature dependence of the
relaxation time, is also briefly discussed
Improving the management of acute non-operable sepsis in a large UK University Teaching Hospital
Probing the stellar populations of early-type galaxies: the SAURON survey
The SAURON project will deliver two-dimensional spectroscopic data of a
sample of nearby early-type galaxies with unprecedented quality. In this paper,
we focus on the mapping of their stellar populations using the SAURON data, and
present some preliminary results on a few prototypical cases.Comment: 12 pages, 6 figures. ASP Conference, Galaxies: the Third Dimension,
Cozumel. Version with higher resolution figures available at
http://www-obs.univ-lyon1.fr/eric.emsellem/papers/cozumel_emsellem.ps.g
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