A rapid DNA extraction method suitable for human papillomavirus detection

Infection with oncogenic human papillomavirus (HPV) genotypes is necessary for the development of cervical cancer. Testing for HPV DNA from liquid based cervical samples can be used as an adjunct to traditional cytological screening. In addition there are ongoing viral load, genotyping, and prevalence studies. Therefore, a sensitive DNA extraction method is needed to maximize the efficiency of HPV DNA detection. The XytXtract Tissue kit is a DNA extraction kit that is rapid and so could be useful for HPV testing, particularly in screening protocols. This study was undertaken to determine the suitability of this method for HPV detection. DNA extraction from HeLa and Caski cell lines containing HPV 18 and 16 respectively together with DNA from five liquid based cervical samples were used in a HPV PCR assay. DNA was also extracted using the QIAamp DNA mini kit (Qiagen, Hilden, Germany) as a comparison. DNA extracts were serially diluted and assayed. HPV DNA was successfully detected in cell lines and cervical samples using the XytXtract Tissue kit. In addition, the XytXtract method was found to be more sensitive than the QIAmp method as determined by a dilution series of the extracted DNA. While the XytXtract method is a closed, the QIAamp method uses a spin column with possible loss of DNA through DNA binding competition of the matrix, which could impact on the final extraction efficiency. The XytXtract is a cheap, rapid and efficient method for extracting HPV DNA from both cell lines and liquid based cervical samples

Spatial scales of genetic patchiness in the western rock lobster Panulirus cygnus

In planktonic dispersers, impediments to dispersal, local selection or large variance in the reproductive success among individuals (sweepstakes reproductive success) can create genetic heterogeneity at local scales. While these processes are well recognized, relatively few studies have investigated the spatial scales over which genetic heterogeneity occurs and how it is distributed across species’ ranges. We investigate population structure in the western rock lobster Panulirus cygnus, a commercially exploited species found in shallow and deep-water reef habitats along the Western Australia coastline. We screened 631 individuals from 9 locations across the species’ range for genetic variation at 22 microsatellite loci. Consistent with expectations of extensive larval mixing during an extended planktonic stage, we found no significant genetic differentiation among locations (FST = 0.003, G’’ST = 0.007). Despite the lack of large-scale geographic structure, small but significant positive spatial autocorrelation (SA) was detected over distances up to 40 km. Two-dimensional local SA analysis confirmed that fine-scale genetic heterogeneity was common throughout the species’ range. An intriguing aspect of these results is that SA was based on juvenile and adult lobsters, suggesting restricted movement or spatial cohesion of individuals after settlement

A rapid non-destructive DNA extraction method for insects and other arthropods

Preparation of arthropods for morphological identification often damages or destroys DNA within the specimen. Conversely, DNA extraction methods often destroy the external physical characteristics essential for morphological identification. We have developed a rapid, simple and non-destructive DNA extraction technique for arthropod specimens. This technique was tested on four arthropod orders, using specimens that were fresh, preserved by air drying, stored in ethanol, or collected with sticky or propylene glycol traps. The technique could be completed in twenty minutes for Coleoptera, Diptera and Hemiptera, and two minutes for the subclass Acarina, without significant distortion, discolouration, or other damage to the specimens

Recognizing and Preventing Overexposure to Methylmercury from Fish and Seafood Consumption: Information for Physicians

Fish is a valuable source of nutrition, and many people would benefit from eating fish regularly. But some people eat a lot of fish, every day or several meals per week, and thus can run a significant risk of overexposure to methylmercury. Current advice regarding methylmercury from fish consumption is targeted to protect the developing brain and nervous system but adverse health effects are increasingly associated with adult chronic low-level methylmercury exposure. Manifestations of methylmercury poisoning are variable and may be difficult to detect unless one considers this specific diagnosis and does an appropriate test (blood or hair analysis). We provide information to physicians to recognize and prevent overexposure to methylmercury from fish and seafood consumption. Physicians are urged to ask patients if they eat fish: how often, how much, and what kinds. People who eat fish frequently (once a week or more often) and pregnant women are advised to choose low mercury fish

Search for Nanosecond Optical Pulses from Nearby Solar‐Type Stars

With "Earth 2000" technology we could generate a directed laser pulse that outshines the broadband visible light of the Sun by 4 orders of magnitude. This is a conservative lower bound for the technical capability of a communicating civilization; optical interstellar communication is thus technically plausible. We have built a pair of systems to detect nanosecond pulsed optical signals from a target list that includes some 13,000 Sun-like stars, and we have made some 16,000 observations totaling nearly 2400 hr during five years of operation. A beam splitter-fed pair of hybrid avalanche photodetectors at the 1.5 m Wyeth Telescope at the Harvard/Smithsonian Oak Ridge Observatory (Agassiz Station) triggers on a coincident pulse pair, initiating measurement of pulse width and intensity at subnanosecond resolution. An identical system at the 0.9 m Cassegrain at Princeton's Fitz-Randolph Observatory performs synchronized observations with 0.1 μs event timing, permitting unambiguous identification of even a solitary pulse. Among the 11,600 artifact-free observations at Harvard, the distribution of 274 observed events shows no pattern of repetition, and is consistent with a model with uniform event rate, independent of target. With one possible exception (HIP 107395), no valid event has been seen simultaneously at the two observatories. We describe the search and candidate events and set limits on the prevalence of civilizations transmitting intense optical pulses

The histone chaperone Vps75 forms multiple oligomeric assemblies capable of mediating exchange between histone H3–H4 tetramers and Asf1–H3–H4 complexes

Wellcome Trust [094090, 097945, 099149]; Medical Research Council [G1100021]. Funding for open access charge: Wellcome Trust.Vps75 is a histone chaperone that has been historically characterized as homodimer by X-ray crystallography. In this study, we present a crystal structure containing two related tetrameric forms of Vps75 within the crystal lattice. We show Vps75 associates with histones in multiple oligomers. In the presence of equimolar H3-H4 and Vps75, the major species is a reconfigured Vps75 tetramer bound to a histone H3-H4 tetramer. However, in the presence of excess histones, a Vps75 dimer bound to a histone H3-H4 tetramer predominates. We show the Vps75-H3-H4 interaction is compatible with the histone chaperone Asf1 and deduce a structural model of the Vps75-Asf1-H3-H4 (VAH) co-chaperone complex using the Pulsed Electron-electron Double Resonance (PELDOR) technique and cross-linking MS/MS distance restraints. The model provides a molecular basis for the involvement of both Vps75 and Asf1 in Rtt109 catalysed histone H3 K9 acetylation. In the absence of Asf1 this model can be used to generate a complex consisting of a reconfigured Vps75 tetramer bound to a H3-H4 tetramer. This provides a structural explanation for many of the complexes detected biochemically and illustrates the ability of Vps75 to interact with dimeric or tetrameric H3-H4 using the same interaction surface.Publisher PDFPeer reviewe

Efficient production of a mature and functional gamma secretase protease

Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants

Efficient production of a mature and functional gamma secretase protease

Baculoviral protein expression in insect cells has been previously used to generate large quantities of a protein of interest for subsequent use in biochemical and structural analyses. The MultiBac baculovirus protein expression system has enabled, the use of a single baculovirus to reconstitute a protein complex of interest, resulting in a larger protein yield. Using this system, we aimed to reconstruct the gamma (γ)-secretase complex, a multiprotein enzyme complex essential for the production of amyloid-β (Aβ) protein. A MultiBac vector containing all components of the γ-secretase complex was generated and expression was observed for all components. The complex was active in processing APP and Notch derived γ-secretase substrates and proteolysis could be inhibited with γ-secretase inhibitors, confirming specificity of the recombinant γ-secretase enzyme. Finally, affinity purification was used to purify an active recombinant γ-secretase complex. In this study we demonstrated that the MultiBac protein expression system can be used to generate an active γ-secretase complex and provides a new tool to study γ-secretase enzyme and its variants

Multiwavelength Properties of the X-ray Sources in the Groth-Westphal Strip Field

We summarize the multiwavelength properties of X-ray sources detected in the 80 ks XMM-Newton observation of the Groth-Westphal Strip. We find 23 XMM-Newton sources within the WFPC2 fields. Ten spectroscopic redshifts are available from the DEEP and CFRS projects and 4 of these show broad Mg II emission (type 1 AGNs). Two of those without any broad lines, nevertheless, have [NeV] emission which is an unambiguous signature of AGN activity, one of which is a narrow-line Seyfert 1 and the other a type 2 AGN. We have made near-infrared (NIR) spectroscopic observations using the Subaru OHS/CISCO spectrometer for five of the X-ray sources for which we found no indication of an AGN activity in the optical spectrum. We have detected H-alpha+[NII] emission in four of them. A broad H-alpha component and/or a large [NII]/H-alpha ratio is seen, suggestive of AGN activity. Nineteen sources have been detected in the Ks band and four of these are extremely red objects (I814-Ks>4). The optical counterparts for the majority of the X-ray sources are bulge-dominated with colors consistent with evolving elliptical galaxies, with starburst/AGN contamination. Assuming that the known local relations among the bulge luminosity,central velocity dispersion, and the mass of the central blackhole hold at about z=1, the AGN bolometric luminosity to Eddington luminosity ratio ranges from 0.3% to 10%. (abridged)Comment: 18 pages, 6 figures, accepted for publication in Astronomical Journa