Complete genome sequences of three novel Pseudomonas fluorescens SBW25 bacteriophages, Noxifer, Phabio, and Skulduggery

Three novel bacteriophages, two of which are jumbophages, were isolated from compost in Auckland, New Zealand. Noxifer, Phabio, and Skulduggery are double-stranded DNA (dsDNA) phages with genome sizes of 278,136 bp (Noxifer), 309,157 bp (Phabio), and 62,978 bp (Skulduggery)

Constitutive Overexpression of Muscarinic Receptors Leads to Vagal Hyperreactivity

BACKGROUND: Alterations in muscarinic receptor expression and acetylcholinesterase (AchE) activity have been observed in tissues from Sudden Infant Death Syndrome (SIDS). Vagal overactivity has been proposed as a possible cause of SIDS as well as of vasovagal syncopes. The aim of the present study was to seek whether muscarinic receptor overexpression may be the underlying mechanism of vagal hyperreactivity. Rabbits with marked vagal pauses following injection of phenylephrine were selected and crossed to obtain a vagal hyperreactive strain. The density of cardiac muscarinic receptors and acetylcholinesterase (AchE) gene expression were assessed. Blood markers of the observed cardiac abnormalities were also sought. METHODOLOGY/PRINCIPAL FINDINGS: Cardiac muscarinic M(2) and M(3) receptors were overexpressed in hyperreactive rabbits compared to control animals (2.3-fold and 2.5-fold, respectively) and the severity of the phenylephrine-induced bradycardia was correlated with their densities. A similar overexpression of M(2) receptors was observed in peripheral mononuclear white blood cells, suggesting that cardiac M(2) receptor expression can be inferred with high confidence from measurements in blood cells. Sequencing of the coding fragment of the M(2) receptor gene revealed a single nucleotide mutation in 83% of hyperreactive animals, possibly contributing for the transcript overexpression. Significant increases in AchE expression and activity were also assessed (AchE mRNA amplification ratio of 3.6 versus normal rabbits). This phenomenon might represent a compensatory consequence of muscarinic receptors overexpression. Alterations in M(2) receptor and AchE expression occurred between the 5th and the 7th week of age, a critical period also characterized by a higher mortality rate of hyperreactive rabbits (52% in H rabbits versus 13% in normal rabbits) and preceeded the appearance of functional disorders. CONCLUSIONS/SIGNIFICANCE: The results suggest that cardiac muscarinic receptor overexpression plays a critical role in the development of vagal hyperreactivity, whereas AchE hyperactivity appears as a compensatory consequence of it. Since similar vagal disorders were observed recently by us in SIDS, muscarinic receptor overexpression could become a marker of risk of vasovagal syncopes and SIDS

Distributed Architecture for Procedural Terrain Generation in Video Games

Procedural generation is often used to create maps and levels in video games in real-time as opposed to loading designer made levels from file. A single player game on a single machine can easily produce the game world by itself. However in a multiplayer game the additional players will also need the game world generated for them. The host machine will need to be capable of generating the game world for all active players by itself which leads to limitations on the number of players that can be playing at once. The goal of this thesis was to understand the relationship between procedural content generation and the distribution of game processes. By distributing content generation to the client machines, it could lighten the load on the host machine negating performance loss from additional clients. Tests were run comparing the time taken when distributing verses not distributing procedural generation requests to the clients. The test showed a significant improvement in generation speed when having client nodes aid the server, especially when the host had a long queue of content needing to be generated.</p

Biogenesis and significance of lipofuscin in the equine thyroid gland : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Pathology at Massey University

Yellow-brown granules of lipofuscin (age pigment) accumulate in the cytoplasm of long-lived cells of many eucaryotes, including man. The granules are derived from lysosomes, and are defined by characteristic morphology, colour, fluorescence, and histochemistry. They increase in number with age in post-mitotic cells, and are regarded as markers of the aging process. Lipofuscin is widely assumed to consist of products of peroxidised fatty acids cross-linked with amino groups of proteins, nucleic acids, and phospholipids, but this theory has not been proven. The occurrence, histology, structure, and composition of lipofuscin in thyrocytes from horses of a wide range of ages were studied. Granules were absent at birth but were widespread by the age of 5 years. In young horses, granules were largest in follicles which contained abnormal colloid. After 5 years the amount of lipofuscin in thyrocytes was not age-related. Lipofuscin was fluorescent, and stained with PAS, Schmorl's, and Masson's Fontana stains, although the staining intensity varied between horses. Lectin histochemistry demonstrated the presence of mannose and/or glucose. Small subpopulations of granules in some sections contained iron and some granules contained DNA. Lipofuscin granules were irregular in size and shape, and consisted of an electron-dense matrix and relatively electron-lucent 'vacuoles', which did not contain lipid. They appeared to fuse with colloid droplets, and small granules were observed within colloid droplets. Thyroid lipofuscin granules isolated by osmotic shock and differential centrifugation showed the same ultrastructure as in situ. The protein content ranged from 15% to 77% w/w (mean = 36%). In contrast, the amino acid composition was constant and similar to that of thyroglobulin. The most distinctive feature of lipofuscin protein was the presence of four proteins of 14-18 kDa. The halide concentration of lipofuscin was approximately twice that of thyroid tissue. Lipofuscin contained no triglycerides, and only small quantities of phospholipids (mean = 1.25% w/w). In contrast, the concentrations of cholesterol and dolichol, up to 19% and 15% respectively, were high although very variable. Small amounts of nuclear DNA were detected. The empirical formula of the rest of lipofuscin indicated that it was principally carbohydrate, which was consistent with the PAS and lectin histochemistry. Most of the lipofuscin mass was analysed and there was no evidence that it arose from lipid peroxidation. The protein fraction of thyroid lipofuscin probably consists of proteolytic intermediates of thyroglobulin. Components from other sources, and turnover of granule contents, contribute to the chemical heterogeneity. The composition of lipofuscin probably varies between tissues. However all lipofuscins are likely to share lysosomal functions such as storage of proteolytic intermediates, metals and dolichol. As with thyroid lipofuscin, they may be more soluble and more readily analysed than is generally assumed in the literature. They may also be active organelles of metabolic significance, rather than inert indicators of the aging process. On the basis of this study, they should be re-evaluated

Assessment of bone ingrowth in titanium implants using MARS spectral CT.

The MARS scanner is a type of computed tomography scanner that uses a wider range of energies than conventional machines, partitioning the range of photon en- ergies into bins. With this advantage, it has many potential uses, one of them being an assessment tool of ingrowth into porous titanium implants, used in the treatment of bone fractures as well as osteodegenerative conditions. If it is successful in this regard, the MARS scanner could become a less invasive form of assessment than the current use of histology. In order to utilise the MARS scanner’s abilities, it is necessary to understand what makes for ideal scanning conditions. This includes study into the effects of different filters, energy bins, voxel size, tube current, and the number of projections. All of these are covered in this thesis, as well as investigation in what effect, if any, a minor camera tangential offset or density of the material submerging the scaffold could have. This work was confounded by the presence of a metal artefact caused by the scaffold itself, yet a suitable set of parameters was obtained to reduce the incident of the arte- fact. Experimentation into the effects of tangential offset and submerging material found them to have an insignificant effect. This thesis may contribute to the goals of the MARS team, and to the advancement of the field of medical imaging. In the short term, this is carried out as a demon- stration of my own abilities to learn and research. It is hoped that this work will contribute to all of these stated goals

Temporal Dynamics of Cortical Adaptation

Adaptation of cortical neurons in response to prior stimulus history and the timecourse of recovery from adaptation were investigated at the level of action potentials using the juxtacellular single-cell loose-patch recording paradigm in the barrel cortex of juvenile rats. An experimental protocol that paired adaptor and test deflections of the principal whisker for a given neuron was applied in two phases of the study. Experiment 1 involved two adaptor conditions, differentiated by the duration of the adaptor stimulus, presented with a limited range of four adaptor-test temporal separations. Experiment 2 involved a single adaptor condition followed by an expanded range of adaptor-test temporal separations. Experiment 1 demonstrated that the time-course for recovery from adaptation was dependent on the duration of the adaptor stimulus. Experiment 2 demonstrated that recovery of action potential responses in the cortical population follows a sigmoidal pattern, in contrast to the exponential decay of adaptation at the post-synaptic potential level. Data from both experiments provided evidence for adaptation increasing trial-to-trial variability of neuronal responses to stimuli as well as reducing discriminability between the presence or absence of a test stimulus of similar characteristics to the adaptor stimulus. Morphological recovery was achieved for a sample of neurons, and case studies of the relationship between neurons’ morphology and functional behaviour provide insights for further investigations into adaptation and functional diversity within the cortex

1080 Poisoning

Highly toxic pesticide, under strict control in the US and UK. Widely used in New Zealand and Australia by licensed authorities to control pest animals. Dogs are highly susceptible