Detection, quantification and genetic analyses of human immunodeficiency virus type 2 (HIV-2) infections in the Gambia, West Africa

Infection with Human Immunodeficiency Virus type 2 (HIV-2) has been investigated in collaborative studies with the MRC unit, Fajara, in The Gambia, West Africa using virological, serological and molecular techniques. Serum antibody levels of anti-HIV-2 were measured with competitive serological assays using culture-derived viral antigens which were applied in field studies in West Africa. These were subsequently replaced with a recombinant β-galactosidase fusion protein of an immunodominant region of the transmembrane glycoprotein (gp36) of HIV-2. Competitive EIAs were demonstrated to be a specific and sensitive means of detecting anti-HIV-2 and, in most cases, for speciation of HIV-1 and HIV-2 infections and for the detection of related non-human primate lentiviruses. A recombinant HIV-2 p26 antigen was produced as a glutathione-S-transferase fusion protein by PCR amplification and cloning into the pGEX-3X expression vector. These studies yielded a soluble recombinant antigen which was used as an immunogen to raise a polyclonal anti-p26- specific reagent. An assay for the detection of p26 antigens was also developed. Partial nucleotide sequence of the p26 gene of four Gambian HIV-2 strains (CBL.20-23) indicated these to be subtype A strains. Nested PCR assays were applied to HIV-2 pro viral DNA detection using oligonucleotide sequences in the Long Terminal Repeat (LTR), pol, and vpx regions of the HIV-2 genome. In a cohort of Gambian seropositive individuals, HIV-2 provirus was detected in DNA extracted from PBMCs in 84/86 (97%) of individuals with LTR primers and 39/41 (95%) in a similarly conserved region of pol (integrase). LTR sequences and recombinant Pfu DNA polymerase, rather than Taq polymerase, were applied in a radiometric incorporation assay for quantification of HIV-2 proviral DNA and evaluated by an end-point limiting dilution method. A wide range of proviral DNA levels were found in HIV-2-infected individuals where increased proviral loads, expressed as copies per 105 CD4-positive lymphocytes, were strongly associated with CD4 depletion. Nested HIV-1 and HIV-2 PCR primers were also used to identify dual infections. Amplification and direct sequence analysis of the U3 region of the HIV-2 LTR, from either proviral DNA or viral RNA, indicated a high level of sequence conservation of four cis-acting elements in vivo. A PCR-based approach to genotyping HIV-2 strains was also developed, capable of differentiating HIV-2 subtype A strains from subtype B or SIV-like viruses based on U3 sequence-specificity. Subtype A viruses were found to predominate in the Gambian samples analysed

Nineteenth Century Constitutional Amendment in Maine

The state of Maine has had but one constitution in its one hundred and forty-four year existence. The document itself, however, has been amended nearly one hundred times. Thirty of these amendments came before the close of the nineteenth century; most of the subsequent amendments were either suggested initially before the turn of the present century or owe their existence to an amendment approved prior to 1900. What is proposed in this study is an examination of the amendments with particular emphasis upon the conflicting reasons of proponents and opponents of specific measures. This study will attempt to evaluate the necessity and the efficacy of successful alterations of the constitution. It will also attempt to suggest certain trends in the power accorded the three branches of the state government and in the changing role and responsibilities of the electorate. In strictly numerical terms elections, election procedure, and the franchise far outrank any of the other classes of amendments. Some of these were proposed to meet immediate exigencies; others to clarify, simplify or democratize the system of elections and the franchise; a few to restrict the right to vote. The power balance in the state government forms the second major class of amendments. These alterations illustrate the changing positions among the three branches of the government and the electorate. Other noteworthy constitutional changes involved apportionment, debt limitation, taxation, special legislation, and prohibition. All of the amendments are not of equal importance and the space devoted to each is certainly not an infallible guide to their relative importance. Certain successful amendments were proposed many times; others infrequently; still others just a single time. The reasons for a detailed amendment may be simple and just the opposite. Appendices A through H offer a summary of legislative action on amendments throughout the nineteenth century. The above is tempered with the realization that any attempt at historical explanation must deal with failure as well as success and thus a discussion of unsuccessful proposals is an integral part of this study

Structural classification of insecticidal proteins – towards an in silico characterization of novel toxins

The increasing rate of discovery of new toxins with potential for the control of invertebrate pests through next generation sequencing, presents challenges for the identification of the best candidates for further development. A consideration of structural similarities between the different toxins suggest that they may be functionally less diverse than their low sequence similarities might predict. This is encouraging from the prospective of being able to use computational tools to predict toxin targets from their sequences, however more structure/function data are still required to reliably inform such predictions

Male access and success in higher education

The gendered landscape of higher education (hereafter HE) has changed significantly over the past two decades. As has long been the case, men are more likely to secure graduatelevel employment after their degree, although the advantage over women in this respect is now marginal. Men still form the majority of faculty and HE managers. Since the early 1990s, however, women are now more likely to start an undergraduate course than men, to successfully complete it and to achieve a ‘good degree’. Although the gender gap is less significant beyond undergraduate study, women are also more likely to undertake post-graduate courses. The speed and scale of the change in undergraduate participation patterns makes it a social phenomenon meriting further attention

Ringing the eigenmodes from compact manifolds

We present a method for finding the eigenmodes of the Laplace operator acting on any compact manifold. The procedure can be used to simulate cosmic microwave background fluctuations in multi-connected cosmological models. Other applications include studies of chaotic mixing and quantum chaos.Comment: 11 pages, 8 figures, IOP format. To be published in the proceedings of the Cleveland Cosmology and Topology Workshop 17-19 Oct 1997. Submitted to Class. Quant. Gra

Will it gel? Successful computational prediction of peptide gelators using physicochemical properties and molecular fingerprints

The self-assembly of low molecular weight gelators to form gels has enormous potential for cell culturing, optoelectronics, sensing, and for the preparation of structured materials. There is an enormous “chemical space” of gelators. Even within one class, functionalised dipeptides, there are many structures based on both natural and unnatural amino acids that can be proposed and there is a need for methods that can successfully predict the gelation propensity of such molecules. We have successfully developed computational models, based on experimental data, which are robust and are able to identify in silico dipeptide structures that can form gels. A virtual computational screen of 2025 dipeptide candidates identified 9 dipeptides that were synthesised and tested. Every one of the 9 dipeptides synthesised and tested were correctly predicted for their gelation properties. This approach and set of tools enables the “dipeptide space” to be searched effectively and efficiently in order to deliver novel gelator molecules

Neighbourhood Environmental Attributes Associated with Walking in South Australian Adults: Differences between Urban and Rural Areas

Although the health benefits of walking are well established, participation is lower in rural areas compared to urban areas. Most studies on walkability and walking have been conducted in urban areas, thus little is known about the relevance of walkability to rural areas. A computer-assisted telephone survey of 2402 adults (aged ≥18 years) was conducted to determine walking behaviour and perceptions of neighbourhood walkability. Data were stratified by urban (n = 1738) and rural (n = 664). A greater proportion of respondents reported no walking in rural (25.8%) compared to urban areas (18.5%). Compared to urban areas, rural areas had lower walkability scores and urban residents reported higher frequency of walking. The association of perceived walkability with walking was significant only in urban areas. These results suggest that environmental factors associated with walking in urban areas may not be relevant in rural areas. Appropriate walkability measures specific to rural areas should be further researched