Characterization of the Genome of Equine Herpesvirus 1 Subtype 2

Equine herpesvirus type-1 (EHV-1), a member of the Alphaherpesvirinae. is a major cause of abortion and respiratory disease in horses worldwide. It is also associated with a neurological syndrome, neonatal foal disease and more rarely, coital exanthema. Collectively, these diseases represent a significant economic loss to the thoroughbred industry each year. Two antigenically and genetically distinct subtypes of EHV-1 exist. They can be unequivocally differentiated by restriction endonuclease analysis of their DNAs. Molecular epizootiological studies in America and Australia indicate that both subtypes of EHV-1 are respiratory pathogens with the potential to cause abortion, but only subtype 1 has been associated with abortion storms and the neurological form of the disease. Most of the molecular data published concern the subtype 1 virus. At the onset of this project the genome of EHV-1 subtype 2 was totally uncharacterized. This was probably due in part to the original misconception that it was identical to EHV-1 subtype 1 and in part to the relative difficulty of growing this virus to a high titre in tissue culture. The purpose of this work was to determine whether the two subtypes of EHV-1 shared a common genome structure, to construct the first restriction endonuclease maps for EHV-1 subtype 2 and to investigate the homology between this virus and other members of the Alphaherpesvirinae by molecular hybridization and DNA sequence analysis. Electron microscopy of EHV-1 subtype 2 DNA which had been denatured and self-annealed indicated that a sequence of 11kbp approximately at one genome terminus is repeated in inverse orientation at one internal site. The inverted repeats were shown to be separated by a unique sequence of approximately 13kbp. The presence of repeated sequence within the EHV-1 subtype 2 genome was confirmed by hybridization studies using DNA probes isolated from virion DMA. A library of plasmid clones containing Ram HI fragments representing approximately 75% of the genome was prepared, and the clones were then used to derive Bam HI and Eco RI restriction endonuclease maps for EHV-1 subtype 2 DNA. The results show that the EHV-1 subtype 2 genome consists of two segments, L (111kbp) and S (35kbp). The S component consists of a unique sequence (Us; 9.6kpb -16kbp) flanked by inverted repeats (TRs and 9.5kbp - 12.7kbp). Published data indicate that the EHV-1 subtype 1 genome has a similar structure. However, the maps for the two subtypes are quite different. Eco RI and Bam HI cleave within the TRs/IRs , and so it was not possible to determine whether Us inverts relative to the L region, as it does in subtype 1. HSV-1 DNA fragments containing coding sequences for genes which have been shown previously to be well-conserved in the alphaherpesviruses were hybridized to EHV-1 subtype 2 DMA. Thus, the regions of the EHV-1 subtype 2 genome homologous to probes for the HSV-1 genes encoding the ribonucleotide reductase, the major capsid protein, the major DNA-binding protein and the immediate early protein VmwIE175 were identified. Cloned DNA fragments of EHV-1 subtype 2 were used in comparative hybridization experiments to further determine the extent and distribution of homologous sequences in the genomes of both subtypes of EHV-1 and HSV-1. Regions of detectable homology are arranged colinearly along the genomes suggesting that the three viruses share a common gene arrangement. These results imply that it should be possible to predict the locations of most EHV-1 subtype 2 genes on the basis of our existing knowledge of HSV-1 gene location and function. Published data indicate that the S segment is the least related region in the genomes of several members of the Alphaherpesvirinae and that the TRs /Us and IRs /Us junctions have altered in location, relative to adjacent genes, during evolution. To elucidate the nature of the genes near the EHV-1 subtype 2 TRs/Us junction, the DNA sequence of a 4.57kbp Bam HI fragment was determined using the Sanger chain terminating dideoxynucleotide method. The junction was located within a 100bp region by using several M13 clones in a hybridization study, indicating that TRs/IRs and Us are approximately 10.9kbp and 13.1kbp in size respectively. The G+C content of the TRs portion of the fragment is approximately 17% greater that that of the Us portion. An 8bp sequence is tandemly repeated within the TRs. Analysis of the sequence showed that Bam HI 1 contains two complete open reading frames and the parts of two others. The amino acid sequences of predicted EHV-1 subtype 2 proteins were compared with those coded by the S segments of VZV and HSV-1. Homologues of the four EHV-1 genes were detected in both HSV-1 and VZV. The EHV-1 genes and the TRs/Us junction have an arrangement intermediate between that of their HSV-1 and VZV counterparts. One of the EHV-1 subtype 2 genes apparently encodes a glycoprotein

Parking and the visual perception of space

Using measured data we demonstrate that there is an amazing correspondence among the statistical properties of spacings between parked cars and the distances between birds perching on a power line. We show that this observation is easily explained by the fact that birds and human use the same mechanism of distance estimation. We give a simple mathematical model of this phenomenon and prove its validity using measured data

A Game Approach to Teach Environmentally Benign Manufacturing in the Supply Chain

Multidisciplinary models of education are needed to prepare students for their role in a global work environment. Combined with this need is the reality of the new Millennial Generation entering the educational system with a different approach to learning. This paper introduces an interactive, educational engineering game designed to appeal to the Millennial Generation’s learning preferences. Shortfall is a prototype board game with a team approach and a trial and error methodology to introduce students to environmentally benign manufacturing in the supply chain using the automobile industry as a model. After playing the game, quantitative analysis showed that on average, students gained new knowledge and a changed perception of their confidence in their answers. Qualitative analysis of data demonstrated that students felt the game also helped them with the teamwork/communication aspects of supply chain. Future plans involve converting the game to a computer format to streamline its effectiveness for multi-institutional participation

Imaging of tumor hypoxia with [124I]IAZA in comparison with [18F]FMISO and [18F]FAZA – first small animal PET results

PURPOSE: This study was performed to compare the 2-nitroimidazole derivatives [124I]IAZA, [18F]FAZA and well known [18F]FMISO in visualization of tumor hypoxia in a mouse model of human cancer using small animal PET. METHODS: PET imaging of female Balb/c nude mice bearing A431 tumors on a Phillips Mosaic small animal PET scanner was performed 3 h p.i. for all three tracers. Mice injected with [124I]IAZA were scanned again after 24 h and 48 h. In addition to the mice breathing air, in the case of [18F]FAZA and [124I]IAZA a second group of mice for each tracer was kept in an atmosphere of carbogen gas (5% of CO2 + 95 % of O2; from 1 h before to 3 h after injection) to evaluate the oxygenation dependency on uptake (all experiments n = 4). After the final PET scan animals were sacrificed and biodistribution was studied. RESULTS: Mice injected with [18F]FAZA displayed significantly higher tumor-to background (T/B) ratios (5.19 +/- 0.73) compared to those injected with [18F]FMISO (3.98 +/- 0.66; P $lt; 0.05) or [124I]IAZA (2.06 +/- 0.26; P$lt; 0.001) 3 h p.i. Carbogen breathing mice showed lower ratios ([18F]FAZA: 4.06 +/- 0.59; [124I]IAZA: 2.02 +/- 0.36). The T/B ratios increased for [124I]IAZA with time (24 h: 3.83 +/- 0.61; 48 h: 4.20 +/- 0.80), but after these late time points the absolute whole body activity was very low, as could be seen from the biodistribution data (< 0.1 %ID/g for each investigated organ) and ratios were still lower than for [18F]FAZA 3 h p.i. Due to de-iodination uptake in thyroid was high. Biodistribution data were in good agreement with the PET results. CONCLUSIONS: [18F]FAZA showed superior biokinetics compared to [18F]FMISO and [124I]IAZA in this study. Imaging at later time points that are not possible with the short lived 18F labeled tracers resulted in no advantage for [124I]IAZA, i. e. tumor to normal tissue ratios could not be improved. © 1999 Canadian Society for Pharmaceutical Sciences

The Magellanic Edges Survey III. Kinematics of the disturbed LMC outskirts

We explore the structural and kinematic properties of the outskirts of the Large Magellanic Cloud (LMC) using data from the Magellanic Edges Survey (MagES) and Gaia EDR3. Even at large galactocentric radii ($8^\circ<R<11^\circ$), we find the north-eastern LMC disk is relatively unperturbed: its kinematics are consistent with a disk of inclination ~$36.5^\circ$ and line-of-nodes position angle ~$145^\circ$ east of north. In contrast, fields at similar radii in the southern and western disk are significantly perturbed from equilibrium, with non-zero radial and vertical velocities, and distances significantly in front of the disk plane implied by our north-eastern fields. We compare our observations to simple dynamical models of the Magellanic/Milky Way system which describe the LMC as a collection of tracer particles within a rigid potential, and the Small Magellanic Cloud (SMC) as a rigid Hernquist potential. A possible SMC crossing of the LMC disk plane ~400 Myr ago, in combination with the LMC's infall to the Milky Way potential, can qualitatively explain many of the perturbations in the outer disk. Additionally, we find the claw-like and arm-like structures south of the LMC have similar metallicities to the outer LMC disk ([Fe/H]~-1), and are likely comprised of perturbed LMC disk material. The claw-like substructure is particularly disturbed, with out-of-plane velocities >60 km s$^{-1}$ and apparent counter-rotation relative to the LMC's disk motion. More detailed N-body models are necessary to elucidate the origin of these southern features, potentially requiring repeated interactions with the SMC prior to ~1 Gyr ago.Comment: Accepted by MNRA

The Magellanic Edges Survey II. Formation of the LMC's northern arm

The highly-substructured outskirts of the Magellanic Clouds provide ideal locations for studying the complex interaction history between both Clouds and the Milky Way (MW). In this paper, we investigate the origin of a >20$^\circ$ long arm-like feature in the northern outskirts of the Large Magellanic Cloud (LMC) using data from the Magellanic Edges Survey (MagES) and Gaia EDR3. We find that the arm has a similar geometry and metallicity to the nearby outer LMC disk, indicating that it is comprised of perturbed disk material. Whilst the azimuthal velocity and velocity dispersions along the arm are consistent with those in the outer LMC, the in-plane radial velocity and out-of-plane vertical velocity are significantly perturbed from equilibrium disk kinematics. We compare these observations to a new suite of dynamical models of the Magellanic/MW system, which describe the LMC as a collection of tracer particles within a rigid potential, and the SMC as a rigid Hernquist potential. Our models indicate the tidal force of the MW during the LMC's infall is likely responsible for the observed increasing out-of-plane velocity along the arm. Our models also suggest close LMC/SMC interactions within the past Gyr, particularly the SMC's pericentric passage ~150 Myr ago and a possible SMC crossing of the LMC disk plane ~400 Myr ago, likely do not perturb stars that today comprise the arm. Historical interactions with the SMC prior to ~1 Gyr ago may be required to explain some of the observed kinematic properties of the arm, in particular its strongly negative in-plane radial velocity.Comment: Accepted by MNRA

The Magellanic Edges Survey I. Description and First Results

We present an overview of, and first science results from, the Magellanic Edges Survey (MagES), an ongoing spectroscopic survey mapping the kinematics of red clump and red giant branch stars in the highly substructured periphery of the Magellanic Clouds. In conjunction with Gaia astrometry, MagES yields a sample of ~7000 stars with individual 3D velocities that probes larger galactocentric radii than most previous studies. We outline our target selection, observation strategy, data reduction and analysis procedures, and present results for two fields in the northern outskirts ($>10^{\circ}$ on-sky from the centre) of the Large Magellanic Cloud (LMC). One field, located in the vicinity of an arm-like overdensity, displays apparent signatures of perturbation away from an equilibrium disk model. This includes a large radial velocity dispersion in the LMC disk plane, and an asymmetric line-of-sight velocity distribution indicative of motions vertically out of the disk plane for some stars. The second field reveals 3D kinematics consistent with an equilibrium disk, and yields $V_{\text{circ}}=87.7\pm8.0$km s$^{-1}$ at a radial distance of ~10.5kpc from the LMC centre. This leads to an enclosed mass estimate for the LMC at this radius of $(1.8\pm0.3)\times10^{10}\text{M}_{\odot}$.Comment: 23 pages, 10 figures. Accepted by MNRA