3,393 research outputs found
Fluorescence in situ Hybridization on DNA Halo Preparations to reveal whole Chromosomes, Telomeres and Gene Loci
The genome is associated with several structures inside cell nuclei, in order to regulate
its activity and anchor it in specific locations. These structures are collectively known
as the nucleoskeleton and include the nuclear lamina, the nucleoli, and nuclear bodies.
Although many variants of fluorescence in situ hybridization (FISH) exist to study
the genome and its organization, these are often limited by resolution and provide
insufficient information on the genome's association with nuclear structures. The DNA
halo method uses high salt concentrations and nonionic detergents to generate DNA
loops that remain anchored to structures within nuclei through attachment regions
within the genome. Here, soluble nuclear proteins, such as histones, lipids, and DNA
not tightly bound to the nuclear matrix, are extracted. This leads to the formation of
a halo of unattached DNA surrounding a residual nucleus which itself contains DNA
closely associated with internal nuclear structures and extraction-resistant proteins.
These extended DNA strands enable increased resolution and can facilitate physical
mapping. In combination with FISH, this method has the added advantage of studying
genomic interactions with all the structures that the genome is anchored by. This
technique, termed HALO-FISH, is highly versatile whereby DNA halos can be coupled
with nucleic acid probes to reveal gene loci, whole chromosomes, alpha satellite,
telomeres and even RNA. This technique provides an insight into nuclear organization
and function in normal cells and in disease progression such as with cancer.EU funded EURO-Laminopathies project and the Brunel Progeria Research Fund
Characterisation of organomineral fertilisers derived from nutrient-enriched biosolids granules
Organomineral fertilisers (OMFs) were produced by coating biosolids granules with urea and potash. Two OMF formulations with N : P2O5 : K2O compositions: 10 : 4 : 4 (OMF10) and 15 : 4 : 4 (OMF15) were developed for application in grassland and arable crops. Routine fertiliser analyses were conducted on four batches of OMF and biosolids granules and compared with a sample of urea to determine key physical and chemical properties of the materials which affect handling and spreading, soil behaviour, and fertiliser value. Bulk and particle densities were in the range of 608 to 618 kg m−3, and 1297 to 1357 kg m−3, respectively. Compression tests showed that OMF particles undergo deformation followed by multiple failures without disintegration of the granules when vertical load was applied. Static particle strength was between 1.18 and 4.33 N mm−2 depending on the particle diameter. The use of a model for fertiliser particle distribution studies showed that OMF granules should be between 1.10 and 5.50 mm in diameter with about 80% of the particles in the range of 2.25 to 4.40 mm to enable application at 18 m tramline spacing. This research utilises novel technology to improve the fertiliser value of biosolids, reduce disposal costs, and deliver a range of environmental benefits associated with recycling
The r'-band luminosity function of Abell1367: a comparison with Coma
We made a large (approximately 1degr x 1degr) r'-band imaging survey of the
central regions of the two nearby clusters of galaxies, Abell1367 and Coma. The
data, presented as a catalog, are used to construct the r'-band luminosity
function (LF) of galaxies in these two clusters, by subtracting the Yasuda et
al. (2001) galaxy counts from our cluster counts. Our Coma luminosity function
is consistent with previous determinations, i.e. providing a faint end slope
alpha = -1.47_-0.09^+0.08, significantly steeper than the one we find for
Abell1367 (alpha = -1.07_-0.16^+0.20). The counts in Abell1367 show a relative
minimum at r' ~ 19, followed by a steep increase faintward. The difference
between the two clusters appears significant, given the consistency of the
experimental conditions in the two clusters. Whereas for Coma we find a
significant increase of the slope of the LF outwards, no such effect is found
for Abell1367.Comment: 12 pages, 8 figures, accepted for publication in A&
Pharmacokinetics of a Single Feeding of Pelleted Cannabidiol in Horses
Claims about cannabidiol (CBD) supplementation improving health and behavior are extensive, but research is lacking. Some studies have shown decreased anxiety behavior in rats, and increased activity in osteoarthritic dogs supplemented with CBD, but even less research exists on horses. This study monitored pharmacokinetics and short-term safety for 3 CBD dosages. Eighteen Quarter Horse geldings were randomly assigned to 3 treatment groups: 50 mg (TXT1), 100 mg (TXT2), and 250 mg (TXT3). Dosage was derived from manufacturer recommendations and existing literature on other species. Horses were fed a single dose of CBD pellets. Blood was collected pre- and post-treatment at 0.5, 1, 2, 4 and 12 hr. Serum was analyzed for CBD and serum chemistry, and plasma was analyzed for a complete blood chemistry (CBC) evaluation. Statistics were completed on serum chemistry using PROC MIXED procedure of SAS. Serum chemistry and CBC results were within normal parameters; however, treatment differences were observed for BUN (TXT1=15.50, TXT2=16.52, TXT3=18.61; P≤0.03) and creatinine (TXT1=1.41, TXT2=1.22, TXT3=1.49; P≤0.01). In other species, peak CBD concentrations occur approximately 2 hr post treatment. Peak serum concentrations were detected in 1 of 6 TXT2 horses and 5 of 6 TXT3 horses at 2 hr post treatment. This data can be used to support further research to determine correct and safe doses of CBD in horses
Experimental evolution reveals that sperm competition intensity selects for longer, more costly sperm
It is the differences between sperm and eggs that fundamentally underpin the differences between the sexes within reproduction. For males, it is theorized that widespread sperm competition leads to selection for investment in sperm numbers, achieved by minimizing sperm size within limited resources for spermatogenesis in the testis. Here, we empirically examine how sperm competition shapes sperm size, after more than 77 generations of experimental selection of replicate lines under either high or low sperm competition intensities in the promiscuous flour beetle Tribolium castaneum. After this experimental evolution, populations had diverged significantly in their sperm competitiveness, with sperm in ejaculates from males evolving under high sperm competition intensities gaining 20% greater paternity than sperm in ejaculates from males that had evolved under low sperm competition intensity. Males did not change their relative investment into sperm production following this experimental evolution, showing no difference in testis sizes between high and low intensity regimes. However, the more competitive males from high sperm competition intensity regimes had evolved significantly longer sperm and, across six independently selected lines, there was a significant association between the degree of divergence in sperm length and average sperm competitiveness. To determine whether such sperm elongation is costly, we used dietary restriction experiments, and revealed that protein-restricted males produced significantly shorter sperm. Our findings therefore demonstrate that sperm competition intensity can exert positive directional selection on sperm size, despite this being a costly reproductive trait
Dissecting the luminosity function of the Coma cluster of galaxies using CFHT wide field images
[Abridged] We determined the luminosity function (LF) of the Coma cluster
galaxies selected by luminosity, and the LF bi-variate in central brightness.
The Coma cluster and control fields were imaged using the CFH12K (42x28 arcmin)
and UH8K (28x28 arcmin) wide-field cameras at the CFHT. Selected HST images
were used for testing. Quantities were derived from measurements in at least
two colors, which have the following features: (1) Galaxies as faint as three
times the luminosity of the brightest globular clusters are in the completeness
region of our data. (2) We have a complete census (in the explored region) of
low surface brightness galaxies with central surface brightness galaxies almost
as low as the faintest so far cataloged ones. (3) The explored area is among
the largest ever sampled with CCDs at comparable depth for any cluster of
galaxies. (4) The error budget includes all sources of errors known to date.
Using HST images we also discovered that blends of globular clusters, not
resolved in individual components due to seeing, look like dwarf galaxies when
observed from the ground and are numerous and bright. The derived Coma LF is
relatively steep (alpha=-1.4) over the 11 magnitudes sampled, but the slope and
shape depend on color. A large population of faint low surface brightness
galaxies was discovered, representing the largest contributor (in number) to
the LF at faint magnitudes. We found a clear progression for a faintening of
the LF from high surface brightness galaxies (mu~20 mag/arcsec2) to galaxies of
very faint central brightnesses (mu~24.5 mag/arcsec2), and some evidence for a
steepening. Compact galaxies, usually classified as stars and therefore not
included in the LF, are found to be a minor population in Coma.Comment: ApJ, in pres
Emission Line Galaxies in the STIS Parallel Survey I: Observations and Data Analysis
In the first three years of operation STIS obtained slitless spectra of
approximately 2500 fields in parallel to prime HST observations as part of the
STIS Parallel Survey (SPS). The archive contains almost 300 fields at high
galactic latitude (|b|>30) with spectroscopic exposure times greater than 3000
seconds. This sample contains 220 fields (excluding special regions and
requiring a consistent grating angle) observed between 6 June 1997 and 21
September 2000, with a total survey area of about 160 square arcminutes. At
this depth, the SPS detects an average of one emission line galaxy per three
fields. We present the analysis of these data, and the identification of 131
low to intermediate redshift galaxies detected by optical emission lines. The
sample contains 78 objects with emission lines that we infer to be redshifted
[OII]3727 emission at 0.43<z<1.7. The comoving number density of these objects
is comparable to that of H-alpha emitting galaxies in the NICMOS parallel
observations. One quasar and three probable Seyfert galaxies are detected. Many
of the emission-line objects show morphologies suggestive of mergers or
interactions. The reduced data are available upon request from the authors.Comment: 58 preprint pages, including 26 figures; accepted for publication in
ApJ
Field-scale evaluation of biosolids-derived organomineral fertilisers applied to ryegrass (Lolium perenne L.) in England
A field-scale experiment was conducted to compare the suitability of two organomineral fertiliser (OMF) formulations (OMF- 10: 4: 4 and OMF- 15: 4: 4) with urea and biosolids granules applied to perennial ryegrass. Results showed a 25% to 30% increase in dry matter yield (DMY) with application of OMF compared with biosolids granules but about 5% lower than urea. For OMF, an average input of 0.8 × N max yielded 0.98 × DMY max which was similar to that of urea; whereas, for biosolids, a yield of 0.92 × DMY max required an input of 0.6 × N max but DMY was lower (P 0.05), in soil extractable P. The application of OMF at rates which do not exceed the optimum N rate for the grass crop should not induce significant changes in soil P Index including application to soils with satisfactory P levels. OMF application strategies are discussed which will enable minimising environmental concerns and maximising fertiliser use efficiency
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