496 research outputs found

    Evolutionary Biology and Drug Development

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    Evolutionary rates at codon sites may be used to align sequences and infer protein domain function

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    <p>Abstract</p> <p>Background</p> <p>Sequence alignments form part of many investigations in molecular biology, including the determination of phylogenetic relationships, the prediction of protein structure and function, and the measurement of evolutionary rates. However, to obtain meaningful results, a significant degree of sequence similarity is required to ensure that the alignments are accurate and the inferences correct. Limitations arise when sequence similarity is low, which is particularly problematic when working with fast-evolving genes, evolutionary distant taxa, genomes with nucleotide biases, and cases of convergent evolution.</p> <p>Results</p> <p>A novel approach was conceptualized to address the "low sequence similarity" alignment problem. We developed an alignment algorithm termed FIRE (<b><it>F</it></b>unctional <b><it>I</it></b>nference using the <b><it>R</it></b>ates of <b><it>E</it></b>volution), which aligns sequences using the evolutionary rate at codon sites, as measured by the <it>dN</it>/<it>dS </it>ratio, rather than nucleotide or amino acid residues. FIRE was used to test the hypotheses that evolutionary rates can be used to align sequences and that the alignments may be used to infer protein domain function. Using a range of test data, we found that aligning domains based on evolutionary rates was possible even when sequence similarity was very low (for example, antibody variable regions). Furthermore, the alignment has the potential to infer protein domain function, indicating that domains with similar functions are subject to similar evolutionary constraints. These data suggest that an evolutionary rate-based approach to sequence analysis (particularly when combined with structural data) may be used to study cases of convergent evolution or when sequences have very low similarity. However, when aligning homologous gene sets with sequence similarity, FIRE did not perform as well as the best traditional alignment algorithms indicating that the conventional approach of aligning residues as opposed to evolutionary rates remains the method of choice in these cases.</p> <p>Conclusions</p> <p>FIRE provides proof of concept that it is possible to align sequences and infer domain function by using evolutionary rates rather than residue similarity. This represents a new approach to sequence analysis with a wide range of potential applications in molecular biology.</p

    The Drosophila retinoblastoma binding protein 6 family member has two isoforms and is potentially involved in embryonic patterning.

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    The human retinoblastoma binding protein 6 (RBBP6) is implicated in esophageal, lung, hepatocellular and colon cancers. Furthermore, RBBP6 was identified as a strong marker for colon cancer prognosis and as a predisposing factor in familial myeloproliferative neoplasms. Functionally, the mammalian protein interacts with p53 and enhances the activity of Mdm2, the prototypical negative regulator of p53. However, since RBBP6 (known as PACT in mice) exists in multiple isoforms and pact−/− mice exhibit a more severe phenotype than mdm2−/− mutants, it must possess some Mdm2-independent functions. The function of the invertebrate homologue is poorly understood. This is complicated by the absence of the Mdm2 gene in both Drosophila and Caenorhabditis elegans. We have experimentally identified the promoter region of Snama, the Drosophila homologue, analyzed potential transcription factor binding sites and confirmed the existence of an additional isoform. Using band shift and co-immunoprecipitation assays combined with mass spectrometry, we found evidence that this gene may be regulated by, amongst others, DREF, which regulates hundreds of genes related to cell proliferation. The potential transcription factors for Snama fall into distinct functional groups, including anteroposterior embryonic patterning and nucleic acid metabolism. Significantly, previous work in mice shows that pact−/− induces an anteroposterior phenotype in embryos when rescued by simultaneous deletion of p53. Taken together, these observations indicate the significance of RBBP6 proteins in carcinogenesis and in developmental defects.SP201

    Capacity building efforts for rabies diagnosis in resource-limited countries in Sub-Saharan Africa: a case report of the central veterinary laboratory in Benin (Parakou)

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    Rabies has been listed as a priority zoonotic disease in many African countries and the countdown to reach the goal of eliminating dog-mediated human rabies deaths by 2030 means that disease control measures need to be applied fast. In this context, an essential pillar of any national plan to control rabies is the implementation of reliable diagnostic techniques to ensure the success of field surveillance systems. Although many African countries have received international support for the control of rabies-some countries, like Benin, have not received a similar level of support. Indeed, until 2018, Benin was not able to diagnose rabies and rabies diagnosis in animals as well as humans relied solely on observed clinical symptoms. Although the Central Veterinary Laboratory (CVL) of Parakou had the equipment to implement two recommended tests, the lack of specific reagents and skills prevented the implementation of a rabies diagnostic service. Here we present the joint efforts of the national authorities in Benin, intergovernmental agencies, and non-governmental organizations to assess the strengths and weaknesses of the government's rabies control efforts. We have applied the Stepwise Approach toward Rabies Elimination (SARE) analysis, implemented rabies diagnostic capacities at the CVL of Parakou, characterized strains of rabies virus circulating in Benin, and finally integrated an inter-laboratory comparison program

    Sensitivity and specificity of real-time reverse transcription polymerase chain reaction, histopathology, and immunohistochemical labeling for the detection of Rift Valley fever virus in naturally infected cattle and sheep

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    Real-time reverse transcription polymerase chain reaction (real-time RT-PCR), histopathology, and immunohistochemical labeling (IHC) were performed on liver specimens from 380 naturally infected cattle and sheep necropsied during the 2010 Rift Valley fever (RVF) epidemic in South Africa. Sensitivity (Se) and specificity (Sp) of realtime RT-PCR, histopathology, and IHC were estimated in a latent-class model using a Bayesian framework. The Se and Sp of real-time RT-PCR were estimated as 97.4% (95% confidence interval [CI] = 95.2–98.8%) and 71.7% (95% CI = 65–77.9%) respectively. The Se and Sp of histopathology were estimated as 94.6% (95% CI = 91–97.2%) and 92.3% (95% CI = 87.6– 95.8%), respectively. The Se and Sp of IHC were estimated as 97.6% (95% CI = 93.9–99.8%) and 99.4% (95% CI = 96.9– 100%), respectively. Decreased Sp of real-time RT-PCR was ascribed to cross-contamination of samples. Stratified analysis of the data suggested variations in test accuracy with fetuses and severely autolyzed specimens. The Sp of histopathology in fetuses (83%) was 9.3% lower than the sample population (92.3%). The Se of IHC decreased from 97.6% to 81.5% in the presence of severe autolysis. The diagnostic Se and Sp of histopathology was higher than expected, confirming the value of routine postmortem examinations and histopathology of liver specimens. Aborted fetuses, however, should be screened using a variety of tests in areas endemic for RVF, and results from severely autolyzed specimens should be interpreted with caution. The most feasible testing option for countries lacking suitably equipped laboratories seems to be routine histology in combination with IHC.http://jvdi.sagepub.comam2014mn201

    Verbalising OWL ontologies in isiZulu with Python

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    Ontologies as a component of Semantic Web technologies are used in Sub-Saharan Africa mainly as part of ontology-driven information systems that may include an interface in a local language. IsiZulu is one such local language, which is spoken by about 23 million people in South Africa, and for which verbalisation patterns to verbalise an ontology exist. We have implemented the algorithms corresponding to these patterns in Python so as to link it most easily to the various technologies that use ontologies and for other NLP tasks. This was linked to Owlready, a new Python-based OWL API, so as to verbalise an ontology in isiZulu. The verbaliser can run in `ontology inside' mode, outputting the sentences in the terminal for further processing in an ontology-driven information system, and in GUI mode that displays colour-coded natural language sentences for users such as domain experts and linguists. The demo will showcase its features

    Roles of traditional medicine and traditional healers for rabies prevention and potential impacts on post-exposure prophylaxis : a literature review

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    INTRODUCTION : Globally, traditional medicine is widely used to treat a variety of injuries and illnesses, including dog bites, and exposures that are risky for rabies. However, efficacy of most traditional remedies used for rabies prevention or treatment has not been demonstrated in controlled trials or proven in community-based surveys. METHODS : Six databases were searched including the terms rabies, traditional treatment, traditional remedy, traditional therapy, traditional medicine, and medicinal treatment to review traditional remedies used in the prevention and treatment of rabies. In addition, published literature of rabies transmission dynamics was used to estimate statistical likelihood of dog bite victims developing rabies to provide clarity as to why traditional healers have a high apparent success rate when preventing death from rabies in victims bitten by suspected rabid dogs. RESULTS : Literature review yielded 50 articles, including three controlled experiments, that described use of traditional remedies for rabies prevention and treatment. Traditional remedies for rabies ranged from plant- or animal-based products to spiritual rituals; however, only a few controlled mice trials were conducted, and none of these trials demonstrated efficacy in preventing or treating rabies. Risk of dying from rabies after a bite from a dog with unknown rabies status is low, 1.90% (0.05%-29.60%). Therefore, traditional healers had a 98.10% (70.40%-99.95%) apparent success rate in preventing death from suspected rabid dog bites despite inefficaciousness of herbal remedies. CONCLUSION : There was no universal plant species or route of administration that was consistently used for rabies prevention or treatment across countries. No traditional remedy was efficacious in the prevention or treatment of rabies in randomized controlled experiments. Understanding the cultural context under which traditional remedies are used may facilitate collaboration of traditional healers with the modern medical system to ensure timely and appropriate use of proven therapies for prevention and clinical management of rabies.https://journals.plos.org/plosntdsdm2022BiochemistryGeneticsMicrobiology and Plant Patholog

    The emergence of insecticide resistance in central Mozambique and potential threat to the successful indoor residual spraying malaria control programme.

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    BACKGROUND: Malaria vector control by indoor residual spraying was reinitiated in 2006 with DDT in Zambézia province, Mozambique. In 2007, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of this programme as carried out by the Malaria Decision Support Project. METHODS: Mosquitoes were captured daily through a series of 114 window exit traps located at 19 sentinel sites, identified to species and analysed for sporozoites. Anopheles mosquitoes were collected resting indoors and tested for insecticide resistance following the standard WHO protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 15 years. RESULTS: A total of 3,769 and 2,853 Anopheles gambiae s.l. and Anopheles funestus, respectively, were captured from window exit traps throughout the period. In 2010 resistance to the pyrethroids lambda-cyhalothrin and permethrin and the carbamate, bendiocarb was detected in An. funestus. In 2006, the sporozoite rate in An. gambiae s.s. was 4% and this reduced to 1% over 4 rounds of spraying. The sporozoite rate for An. funestus was also reduced from 2% to 0 by 2008. Of the 437 Anopheles arabiensis identified, none were infectious. Overall prevalence of P. falciparum in the sentinel sites fell from 60% to 32% between October 2006 and October 2008. CONCLUSION: Both An. gambiae s.s. and An. funestus were controlled effectively with the DDT-based IRS programme in Zambézia, reducing disease transmission and burden. However, the discovery of pyrethroid resistance in the province and Mozambique's policy change away from DDT to pyrethroids for IRS threatens the gains made here
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