Clarification of anomalies in the application of a 2La molecular karyotyping method for the malaria vector Anopheles gambiae

BACKGROUND:Chromosomal inversions have been considered to be potentially important barriers to gene flow in many groups of animals through their effect on recombination suppression in heterokaryotypic individuals. Inversions can also enhance local adaptation in different groups of organisms and may often represent species-specific differences among closely related taxa. We conducted a study to characterize the 2La inversion karyotypes of An. gambiae sensu stricto mosquitoes sampled from the Kilombero Valley (Tanzania) using a newly designed PCR assay.RESULTS:We frequently encountered a (687 bp) fragment which was only present in the Kilombero Valley populations. Laboratory crossing between An. gambiae s.s. from Njage (Tanzania) and Kisumu (Western Kenya) populations resulted in F1 offspring carrying the observed fragment. Karyotype analysis did not indicate differences in 2La region chromosome morphology between individuals carrying the PCR fragments, the 207 bp fragment, or the 687 bp fragement.CONCLUSION:The observed insertion/deletion polymorphism within the region amplified by the 2La PCR diagnostic test may confound the interpretation of this assay and should be well considered in order to maintain an acceptable level of reliability in studies using this assay to describe the distribution and frequency of the 2La inversion among natural populations of An. gambiae s.

Ecological and genetic relationships of the Forest-M form among chromosomal and molecular forms of the malaria vector Anopheles gambiae sensu stricto

<p>Abstract</p> <p>Background</p> <p><it>Anopheles gambiae sensu stricto</it>, one of the principal vectors of malaria, has been divided into two subspecific groups, known as the M and S molecular forms. Recent studies suggest that the M form found in Cameroon is genetically distinct from the M form found in Mali and elsewhere in West Africa, suggesting further subdivision within that form.</p> <p>Methods</p> <p>Chromosomal, microsatellite and geographic/ecological evidence are synthesized to identify sources of genetic polymorphism among chromosomal and molecular forms of the malaria vector <it>Anopheles gambiae s.s</it>.</p> <p>Results</p> <p>Cytogenetically the Forest M form is characterized as carrying the standard chromosome arrangement for six major chromosomal inversions, namely 2La, 2Rj, 2Rb, 2Rc, 2Rd, and 2Ru. Bayesian clustering analysis based on molecular form and chromosome inversion polymorphisms as well as microsatellites describe the Forest M form as a distinct population relative to the West African M form (Mopti-M form) and the S form. The Forest-M form was the most highly diverged of the <it>An. gambiae s.s</it>. groups based on microsatellite markers. The prevalence of the Forest M form was highly correlated with precipitation, suggesting that this form prefers much wetter environments than the Mopti-M form.</p> <p>Conclusion</p> <p>Chromosome inversions, microsatellite allele frequencies and habitat preference all indicate that the Forest M form of <it>An. gambiae </it>is genetically distinct from the other recognized forms within the taxon <it>Anopheles gambiae sensu stricto</it>. Since this study covers limited regions of Cameroon, the possibility of gene flow between the Forest-M form and Mopti-M form cannot be rejected. However, association studies of important phenotypes, such as insecticide resistance and refractoriness against malaria parasites, should take into consideration this complex population structure.</p

High-Pressure Phase Behavior for Poly(ethylene glycol) and 1,1,1,2-Tetrafluorethane Systems

The development of polymeric systems for drug deliveryhas received attention with the aim of producing new systems as an alternative to conventional drug therapy. The design of new systems for this purpose in a compressed medium requires a knowledge of the phase behavior for the polymeric matrix in the high-pressure fluids. This work reports the phase equilibrium experimental data of binary systems involving poly(ethylene glycol) (PEG) with molecular weights of 1000and 2000 g·mol−1 and 1,1,1,2-tetrafluoroethane (HFA-134a). The experimental data were obtained in a high-pressure variable-volume viewing cell based on the static synthetic method at temperatures from 287.4 to 334.2 K, pressures of up to 29.81 MPa, and a PEG concentration in the range of 1 to 7 wt %. Liquid−liquid equilibrium,liquid−liquid−vapor equilibrium, and, in some cases, solid−liquid equilibrium were observed under the experimental conditions of pressure, temperature, and compositions investigated. The experimental results show that temperature and pressure have significant influences on the solubility of PEG in HFA-134a. The solid-phase formation for the system PEG + HFA-134a, in the range of values investigated for temperature, pressure, and compositions, is influenced by the molecular weight of the polymer.Fil: Oliveira Meneses, Marcela. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: Dariva, Claudio. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: Rodrigues Borges, Gustavo. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; BrasilFil: da Rocha, Sandro R. P.. Virginia Commonwealth University; Estados UnidosFil: Zabaloy, Marcelo Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Franceschi, Elton. Universidade Tiradentes. Programa de Pós-Graduação em Engenharia de Processos. Instituto de Tecnologia e Pesquisa; Brasi

Centrin-deficient Leishmania mexicana confers protection against Old World visceral leishmaniasis

Abstract Leishmaniasis is one of the top neglected tropical diseases with significant morbidity and mortality in low and middle-income countries (LMIC). However, this disease is also spreading in the developed world. Currently, there is a lack of effective strategies to control this disease. Vaccination can be an effective measure to control leishmaniasis and has the potential to achieve disease elimination. Recently, we have generated centrin gene-deleted new world L. mexicana (LmexCen −/− ) parasites using CRISPR/Cas9 and showed that they protect mice against a homologous L. mexicana infection that causes cutaneous disease. In this study, we tested whether LmexCen −/− parasites can also protect against visceral leishmaniasis caused by L. donovani in a hamster model. We showed that immunization with LmexCen −/− parasites is safe and does not cause lesions. Furthermore, such immunization conferred protection against visceral leishmaniasis caused by a needle-initiated L. donovani challenge, as indicated by a significant reduction in the parasite burdens in the spleen and liver as well as reduced mortality. Similar control of parasite burden was also observed against a sand fly mediated L. donovani challenge. Importantly, immunization with LmexCen −/− down-regulated the disease promoting cytokines IL-10 and IL-4 and increased pro-inflammatory cytokine IFN-γ resulting in higher IFN-γ/IL-10 and IFN-γ/IL4 ratios compared to non-immunized animals. LmexCen −/− immunization also resulted in long-lasting protection against L. donovani infection. Taken together, our study demonstrates that immunization with LmexCen −/− parasites is safe and efficacious against the Old World visceral leishmaniasis