36156927
Origin of hepatitis delta virus.
This article addresses some of the questions relating to how hepatitis delta virus (HDV), an agent so far unique in the animal world, might have arisen. HDV was discovered in patients infected with hepatitis B virus (HBV). It generally makes HBV infections more damaging to the liver. It is a subviral satellite agent that depends upon HBV envelope proteins for its assembly and ability to infect new cells. In other aspects of replication, HDV is both independent of and very different from HBV. In addition, the small single-stranded circular RNA genome of HDV, and its mechanism of replication, demonstrate an increasing number of similarities to the viroids - a large family of helper-independent subviral agents that cause pathogenesis in plants.
28296194
Retrovirus Genome Replication: Priming Specificities of Plus-Strand DNA Synthesis
SUMMARY The retroviral reverse transcriptase is a multifunctional protein. Not only does it contain both RNA- and DNA-directed DNA synthesis activities but also it contains an endonuclease activity necessary for the integration of viral RNA and a RNase H. This latter activity can reduce to oligoribonucleotides viral RNA that has been reverse transcribed into minus-strand DNA. However, during avian retrovirus genome replication it does this in a highly specific manner so as to generate a specific 12-base primer for plus-strand DNA synthesis. Even though many other oligoribonucleotides are also made there is an efficient selection of the specific primer followed by its efficient utilization in plus-strand DNA synthesis, and subsequent removal. We have used a reconstructed system to gain an understanding of the factors that contribute towards these observed specificities.
27724235
Avian RNA tumor virus DNA before and after integration into the host genome.
33501684
Tumor virus ribonucleic acid directed deoxyribonucleic acid synthesis: nucleotide sequence at the 5' terminus of nascent deoxyribonucleic acid.
11606238
Hepatitis delta virus.
Hepatitis delta virus (HDV) is a sub-viral agent that is dependent for its life cycle on hepatitis B virus (HBV). The help it obtains from HBV is limited to the sharing of envelope proteins. These proteins are needed to facilitate the assembly of the HDV genome into new virus particles, and in turn, to allow the attachment and entry of HDV into new host cells. In other respects, the replication of the small single-stranded circular RNA genome of HDV is independent of HBV. HDV genome replication produces two forms of a RNA-binding protein known as the long and small delta antigens (Ag). All other proteins needed for HDV genome replication, especially the RNA-directed RNA polymerase activity, are provided by the host cell. This mini-review article is a mixture of personal perspective and speculations about the future of HDV research. It starts with a brief overview of HDV and its replication, notes some of the major unresolved questions, and directs the interested reader to more detailed reviews.
12985098
A note on the incorporation of amino acids by hamster embryo cells in monolayer culture.
35383077
SmartShape™ technology. Modifying the shape of the beef cuberoll and the consumer response to shaped scotch fillet steaks.
SmartShape™ is a novel meat processing technology that uses air pressure to compress and elongate whole cold-boned primals and packages them to retain form. A two stage study was conducted. The first stage established the ability of the SmartShape™ treated beef cube roll (m. longissimus lumborum) to retain shape in a commercial setting. Twelve hours chilling time following treatment was found to be adequate for steaks to retain their shape for up to 24h after slicing. Steak shape and size did not change substantially until after cooking, when the steaks looked less formed. In the second stage a survey was conducted of 421 consumers to clarify the response to the shaping of a subset of raw and cooked scotch fillet steaks. There was no difference in preference for shaped or control steaks. A secondary survey found that informed consumers were more amenable to the SmartShape™ scotch fillet steaks presented here, but would not pay a premium for them.
16183837
The modifying effect of the building envelope on population exposure to PM2.5 from outdoor sources
A number of studies have estimated population exposure to PM2.5 by examining modeled or measured outdoor PM2.5 levels. However, few have taken into account the mediating effects of building characteristics on the ingress of PM2.5 from outdoor sources and its impact on population exposure in the indoor domestic environment. This study describes how building simulation can be used to determine the indoor concentration of outdoor-sourced pollution for different housing typologies and how the results can be mapped using building stock models and Geographical Information Systems software to demonstrate the modifying effect of dwellings on occupant exposure to PM2.5 across London. Building archetypes broadly representative of those in the Greater London Authority were simulated for pollution infiltration using EnergyPlus. In addition, the influence of occupant behavior on indoor levels of PM2.5 from outdoor sources was examined using a temperature-dependent window-opening scenario. Results demonstrate a range of I/O ratios of PM2.5, with detached and semi-detached dwellings most vulnerable to high levels of infiltration. When the results are mapped, central London shows lower I/O ratios of PM2.5 compared with outer London, an apparent inversion of exposure most likely caused by the prevalence of flats rather than detached or semi-detached properties.
14002416
Strong and weak male mutation bias at different sites in the primate genomes: insights from the human-chimpanzee comparison.
Male mutation bias is a higher mutation rate in males than in females thought to result from the greater number of germ line cell divisions in males. If errors in DNA replication cause most mutations, then the magnitude of male mutation bias, measured as the male-to-female mutation rate ratio (alpha), should reflect the relative excess of male versus female germ line cell divisions. Evolutionary rates averaged among all sites in a sequence and compared between mammalian sex chromosomes were shown to be indeed higher in males than in females. However, it is presently unknown whether individual classes of substitutions exhibit such bias. To address this issue, we investigated male mutation bias separately at non-CpG and CpG sites using human-chimpanzee whole-genome alignments. We observed strong male mutation bias at non-CpG sites: alpha in the X-autosome comparison was approximately 6-7, which was similar to the male-to-female ratio in the number of germ line cell divisions. In contrast, mutations at CpG sites exhibited weak male mutation bias: alpha in the X-autosome comparison was only approximately 2-3. This is consistent with the methylation-induced and replication-independent mechanism of CpG transitions, which constitute the majority of mutations at CpG sites. Interestingly, our study also indicated weak male mutation bias for transversions at CpG sites, implying a spontaneous mechanism largely not associated with replication. Male mutation bias was equally strong at CpG and non-CpG sites located within unmethylated "CpG islands," suggesting the replication-dependent origin of these mutations. Thus, we found that the strength of male mutation bias is nonuniform in the primate genomes. Importantly, we discovered that male mutation bias depends on the proportion of CpG sites in the loci compared. This might explain the differences in the magnitude of primate male mutation bias observed among studies.
11148995
Electrodermal reactivity and its association to substance use disorders.
Poor electrodermal response modulation is associated with substance use disorders, but the specificity of the relationship has not been tested. To test this, 112 college students were assessed for psychiatric symptoms using structured interviews and for ability to modulate skin conductance responses to 2-s 92- or 110-dB white noise blasts that varied in temporal predictability. Twenty-eight good and 28 poor modulators were compared on symptoms of alcohol and illicit drug use disorders, personality disorders (antisocial, borderline, histrionic, and narcissistic), social and specific phobia, and depression. As expected, poor modulators had significantly more symptoms of substance use disorders than good modulators. Groups did not differ in symptoms of anxiety disorder, depression, or personality disorders marked by disinhibition. Poor electrodermal response modulation may reflect a biological risk factor for substance use disorders in particular.
12906963
Unique issues in research and evaluation in rural and remote locations: is there a place for specific research training?
BACKGROUND
There is increased interest in building research capacity in rural health research in Australia and internationally. In Australia, the Primary Health Care Research Evaluation and Development program funded by the Australian Government has supported this move. Overall this program aims to build the quantum of primary healthcare research to underpin clinical practice, health systems improvement, and policy. In order to achieve this objective, one strand of the program aims to build research capacity among practitioners. In implementing this program in rural and remote areas of the west of South Australia, the Spencer Gulf Rural Health School has identified methodological and research design issues faced by practitioners who are researching in their communities. These issues include problems encountered in living and researching in the same location and accessing small-scale statistical information. We were interested to know whether there was interest in a formal course (Rural Research and Evaluation) that would address these issues and provide information about community-based research designs.


METHODS
A cross-sectional anonymous survey was designed and sent to 141 organisations in the health, human service, and local government sectors in regional South Australia. Respondents were asked to evaluate the demand and interest for a new course--Rural Research and Evaluation. The term 'rural' was used to refer to both rural and remote locations. Information was sought on the respondent's role in the organisation, current level of research participation, views about the proposed course content, and factors that the respondent thought would facilitate or inhibit their participation. The majority of questions were close-ended.


RESULTS
Sixty surveys were returned giving a 42.5% response rate. Data were analysed using descriptive statistics. A high level of research and evaluation activity was reported with 80% of respondents undertaking research or evaluation as part of their professional role. There was also agreement that all the proposed topics were important to be included in a course. Each of the topics was ranked at four or five on a five-point scale by at least 58% of respondents. The topic 'understanding evaluation methodologies' was ranked at four or five by 85% of respondents, making it the most highly ranked topic. There was also consensus about the features respondents thought would make the course attractive for them to study. Over half (62%) of the respondents ranked having lecturers with a broad rural research background at five, very important, on a five-point scale. Almost half (48%) of the respondents ranked online delivery at five, a very important factor in making the course attractive to study.


CONCLUSIONS
Those interested in research and evaluation may have been more likely to return the survey and there may have been respondent bias in this regard. Therefore the results must be interpreted with caution. However, the level of agreement with the proposed course topics may suggest that these reflect important issues in undertaking research and evaluation in rural and remote locations. If this is the case there is value in discussion about how these issues are dealt with in different contexts in order to overcome some of the barriers to effective research.