Xp54 and related (DDX6-like) RNA helicases: roles in messenger RNP assembly, translation regulation and RNA degradation

The DEAD-box RNA helicase Xp54 is an integral component of the messenger ribonucleoprotein (mRNP) particles of Xenopus oocytes. In oocytes, several abundant proteins bind pre-mRNA transcripts to modulate nuclear export, RNA stability and translational fate. Of these, Xp54, the mRNA-masking protein FRGY2 and its activating protein kinase CK2α, bind to nascent transcripts on chromosome loops, whereas an Xp54-associated factor, RapA/B, binds to the mRNP complex in the cytoplasm. Over-expression, mutation and knockdown experiments indicate that Xp54 functions to change the conformation of mRNP complexes, displacing one subset of proteins to accommodate another. The sequence of Xp54 is highly conserved in a wide spectrum of organisms. Like Xp54, Drosophila Me31B and Caenorhabditis CGH-1 are required for proper meiotic development, apparently by regulating the translational activation of stored mRNPs and also for sorting certain mRNPs into germplasm-containing structures. Studies on yeast Dhh1 and mammalian rck/p54 have revealed a key role for these helicases in mRNA degradation and in earlier remodelling of mRNP for entry into translation, storage or decay pathways. The versatility of Xp54 and related helicases in modulating the metabolism of mRNAs at all stages of their lifetimes marks them out as key regulators of post-transcriptional gene expression

Synthesis of ɣ-Cyclodextrin Metal Organic Frameworks and the Encapsulation of Caffeine and Theophylline

Nanoporous, non-toxic, ɣ-cyclodextrin metal organic frameworks (-CDMOFs) have potential applications in fields such as drug delivery and organic compound storage. The properties of many methylxanthines (alkaloids such as caffeine and theophylline) could be improved through -CDMOF encapsulation, yet little research has been performed on the subject. In this study, -CDMOFs were synthesized in order to 1. Determine if the vapor diffusion synthesis method can produce -CDMOF crystals that replicate those in literature and 2. Determine if -CDMOFs are able to encapsulate methylxanthines. The -CDMOFs were synthesized through vapor diffusion of methanol in a solution of ɣ-cyclodextrin and potassium hydroxide (KOH). The synthesized crystals were activated at 25 °C and 45 °C to remove the residual methanol and water, freeing the nanopores of the crystals. The synthesized and activated crystals were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM). Caffeine and theophylline were encapsulated over 24 hours in the -CDMOFs, which were then analyzed using thermogravimetric analysis (TGA). Characterization results aligned with literature confirming a uniform cubic structure of the crystals with sizes primarily ranging from 1 to 10μm, with a median crystallite size of 2 μm. It was determined that 1. Vapor diffusion is a viable synthesis method for -CDMOFs and 2. -CDMOFs are able to encapsulate theophylline, however the data was not conclusive enough to confirm the encapsulation of caffein

The use of statistical classifiers for the discrimination of species of the genus Gyrodactylus (Monogenea) parasitizing salmonids

This study applies flexible statistical methods to morphometric measurements obtained via light and scanning electron microscopy (SEM) to discriminate closely related species of Gyrodactylus parasitic on salmonids. For the first analysis, morphometric measurements taken from the opisthaptoral hooks and bars of 5 species of gyrodactylid were derived from images obtained by SEM and used to assess the prediction performance of 4 statistical methods (nearest neighbours; feed-forward neural network; projection pursuit regression and linear discriminant analysis). The performance of 2 methods, nearest neighbours and a feed-forward neural network provided perfect discrimination of G. salaris from 4 other species of Gyrodactylus when using measurements taken from only a single structure, the marginal hook. Data derived from images using light microscopy taken from the full complement of opisthaptoral hooks and bars were also tested and nearest neighbours and linear discriminant analysis gave perfect discrimination of G. salaris from G. derjavini Mikailov, 1975 and G. truttae Gläser, 1974. The nearest neighbours method had the least misclassifications and was therefore assessed further for the analysis of individual hooks. Five morphometric parameters from the marginal hook subset (total length, shaft length, sickle length, sickle proximal width and sickle distal width) gave near perfect discrimination of G. salaris. For perfect discrimination therefore, larger numbers of parameters are required at the light level than at the SEM level

Seasonal variation in fitness levels of professional youth footballers over a competitive season

The use of applied sports science in soccer is growing rapidly. Fitness testing and monitoring of training intensities are now becoming common place in the modern game. Anecdotally it appears that fitness may decrease over the season after initially being high following pre-season. While field tests also suggest this, more precise measures made in controlled lab settings are scarce. Therefore, the current study considered the seasonal variation in fitness parameters of footballers over the course of a professional season. Nineteen professional youth players from Celtic Football Club (age = 18.2 + 0.3 years; height = 175.4 + 6.2 cm; weight = 66.8 + 2.56 kg) completed lab-based tests of aerobic capacity, muscle strength and power at three times throughout the season. Aerobic measures of VO2max were among the highest values for soccer players reported in published literature (at the end of pre- season). Body weight changes occurred in the younger players over the season, and appear to be largely dependant on maturation status. Maximal strength parameters increased across the season and this was reflected in maximal jump heights. However, in the older players increased strength did not improve sprint performance over 5m and 10m. In younger players increasing maximal strength did correlate with improvement in sprint performances. The results suggest that fitness levels can be maintained across the season in older age groups or more mature players. Changes seen in younger players are primarily a result of maturation and resultant changes in body morphology. Furthermore, lab-based tests appear to provide a more detailed profile of a players’ physical status than field-based tests

Elemental analysis of Scottish populations of the ectoparasitic copepod Lepeophtheirus salmonis

Conventional nebulisation ICPMS (Inductively Coupled Plasma Mass Spectrometry), was used to determine the concentration of a broad range of elements in the salmon louse Lepeophtheirus salmonis. Lice samples were collected from Atlantic salmon in seven localities (4 fish farms and 3 wild salmon fisheries) on two separate sampling occasions and prepared for analysis. Sixty six elements were measured, 35 of these were found to be variable and were subjected to univariate and multivariate statistical analysis. The results of the single element comparisons showed that not all individual sites could be discriminated from each other. Sea lice collected from cultured salmonids could be discriminated from those on wild salmonids at the same site using the elements magnesium (less than 0.05%), vanadium (less than 0.01%) and uranium (less than 0.05%). Using discriminant analysis based on 28 elements, the separation of all sampled sea lice localities from each other was clear (100% correct classification) giving each an individual signature. Further analysis examined the effects of sequentially removing elements from the discrimination model in order to determine the minimum number of elements required to obtain satisfactory discrimination of populations. It was found that 16 elements could still provide 100% correct classification, whilst 12 elements still provided 97.30% correct classification. This pilot study has shown elemental analysis to be a potentially successful method for the discrimination of populations of L. salmonis, although the biological basis of the elemental signatures derived remains to be established

Utility of 18S rDNA and ITS sequences as population markers for Lepeophtheirus salmonis (Copepoda: Caligidae) parasitising Atlantic salmon (Salmo salar) in Scotland

Genetic differentiation within the salmon louse Lepeophtheirus salmonis (Krøyer, 1837), was investigated by the sequencing of specific nucleotide regions. Partial sequences of the 18S ribosomal RNA gene and the ribosomal internal transcribed spacer (ITS-1) region from single sea lice were amplified by the polymerase chain reaction (PCR). Lice were collected from wild and farmed Atlantic salmon (Salmo salar L., 1758) from nine selected localities around the Scottish coastline. A 0.9kb fragment of the 18S ribosomal RNA gene was amplified and compared for several samples of lice which showed no observable differences between the lice from different collection sites confirming the absence of cryptic species. The 454 nucleotide ITS-1 sequence showed differences between derived sequences from 13 sea lice samples from 4 collection sites which included 2 farm sites and 2 sites where lice were taken from wild fish. Across all samples, there was a 92.14% similarity in the ITS-1 sequence. The percentage similarity in the ITS-1 sequence in samples of lice from two fish farms were 99.71% (site A) and 95.72% (site D) but only 86.90% (site B) and 86.03% (site C) similarity was shown in lice samples taken from sites where wild salmonids were caught. The greater similarity between the ITS-1 sequence within farm sites may be attributed to a restricted gene flow within lice populations in Atlantic salmon cage sites

Clustering of Very Red Galaxies in the Las Campanas IR Survey

We report results from the first 1000 square arc-minutes of the Las Campanas IR survey. We have imaged 1 square degree of high latitude sky in six distinct fields to a 5-sigma H-band depth of 20.5 (Vega). Optical imaging in the V,R,I,and z' bands allow us to select color subsets and photometric-redshift-defined shells. We show that the angular clustering of faint red galaxies (18 3) is an order of magnitude stronger than that of the complete H-selected field sample. We employ three approaches to estimate $n(z)$ in order to invert w(theta) to derive r_0. We find that our n(z) is well described by a Gaussian with = 1.2, sigma(z) = 0.15. From this we derive a value for r_0 of 7 (+2,-1) co-moving H^{-1} Mpc at = 1.2. This is a factor of ~ 2 larger than the clustering length for Lyman break galaxies and is similar to the expectation for early type galaxies at this epoch.Comment: 5 pages, 2 figures, 1 table. To appear in proceedings of the ESO/ECF/STScI workshop "Deep Fields" held in Garching, Germany, 9-12 October 200

Seasonality and the microhabitat of Microcotyle sebastis Goto, 1894, a monogenean gill parasite of farmed rockfish, Sebastes schlegeli Hilgendorf 1880

A total of 353 farmed rockfish, Sebastes schlegeli Hilgendorf, 1880 were sampled from 3 localities on the Korean coastline over a 12 month period. Full parasitological examination revealed the polyopisthocotylean monogenean Microcotyle sebastis Goto, 1894 to be abundant with infections consistently reaching over 90~100% prevalence throughout the year. A seasonal pattern in parasite abundance on the gills is evident, with the population peaking twice, the largest in winter and again in summer. While the parasitic load on the left and right gills was not dissimilar, parasites within the gill sets were found to favour settlement on the Ⅱ and Ⅲ gill arches. A comparison of parasite abundance with host length, revealed that the smaller length fish classes (less than 17 ㎝ standard body length) had significantly heavier infections than those of larger fish (greater than 17 ㎝ standard body length). This report represents the first record of Microcotyle sebastis on farmed rockfish in Korean coastal waters