Antiplasmodial volatile extracts from Cleistopholis patens Engler & Diels and Uvariastrum pierreanum Engl. (Engl. & Diels) (Annonaceae) growing in Cameroon

In a search for alternative treatment for malaria, plant-derived essential oils extracted from the stem barks and leaves of Cleistopholis patens and Uvariastrum pierreanum (Annonaceae) were evaluated in vitro for antiplasmodial activity against the W2 strain of Plasmodium falciparum. The oils were obtained from 500 g each of stem barks and leaves, respectively, by hydrodistillation, using a Clevenger-type apparatus with the following yields: 0.23% and 0.19% for C. patens and 0.1% and 0.3% for U. pierreanum (w/w relative to dried material weight). Analysis of 10% (v/v) oil in hexane by gas chromatography and mass spectrometry identified only terpenoids in the oils, with over 81% sesquiterpene hydrocarbons in C. patens extracts and U. pierreanum stem bark oil, while the leaf oil from the latter species was found to contain a majority of monoterpenes. For C. patens, the major components were α-copaene, δ-cadinene, and germacrene D for the stem bark oil and β-caryophyllene, germacrene D, and germacrene B for the leaf oil. The stem bark oil of U. pierreanum was found to contain mainly β-bisabolene and α-bisabolol, while α- and β-pinenes were more abundant in the leaf extract. Concentrations of oils obtained by diluting 1-mg/mL stock solutions were tested against P. falciparum in culture. The oils were active, with IC50 values of 9.19 and 15.19 μg/mL for the stem bark and leaf oils, respectively, of C. patens and 6.08 and 13.96 μg/mL, respectively, for those from U. pierreanum. These results indicate that essential oils may offer a promising alternative for the development of new antimalarials

Physical losses could partially explain modest carotenoid retention in dried food products from biofortified cassava

Gari, a fermented and dried semolina made from cassava, is one of the most common foods in West Africa. Recently introduced biofortified yellow cassava containing provitamin A carotenoids could help tackle vitamin A deficiency prevalent in those areas. However there are concerns because of the low retention of carotenoids during gari processing compared to other processes (e.g. boiling). The aim of the study was to assess the levels of true retention in trans–β-carotene during gari processing and investigate the causes of low retention. Influence of processing step, processor (3 commercial processors) and variety (TMS 01/ 1371; 01/1368 and 01/1412) were assessed. It was shown that low true retention (46% on average) during gari processing may be explained by not only chemical losses (i.e. due to roasting temperature) but also by physical losses (i.e. due to leaching of carotenoids in discarded liquids): true retention in the liquid lost from grating negatively correlated with true retention retained in the mash (R = -0.914). Moreover, true retention followed the same pattern as lost water at the different processing steps (i.e. for the commercial processors). Variety had a significant influence on true retention, carotenoid content, and trans-cis isomerisation but the processor type had little effect. It is the first time that the importance of physical carotenoid losses was demonstrated during processing of biofortified crops

The Bacterium Endosymbiont of Crithidia deanei Undergoes Coordinated Division with the Host Cell Nucleus

In trypanosomatids, cell division involves morphological changes and requires coordinated replication and segregation of the nucleus, kinetoplast and flagellum. In endosymbiont-containing trypanosomatids, like Crithidia deanei, this process is more complex, as each daughter cell contains only a single symbiotic bacterium, indicating that the prokaryote must replicate synchronically with the host protozoan. In this study, we used light and electron microscopy combined with three-dimensional reconstruction approaches to observe the endosymbiont shape and division during C. deanei cell cycle. We found that the bacterium replicates before the basal body and kinetoplast segregations and that the nucleus is the last organelle to divide, before cytokinesis. In addition, the endosymbiont is usually found close to the host cell nucleus, presenting different shapes during the protozoan cell cycle. Considering that the endosymbiosis in trypanosomatids is a mutualistic relationship, which resembles organelle acquisition during evolution, these findings establish an excellent model for the understanding of mechanisms related with the establishment of organelles in eukaryotic cells

Discovery of Markers of Exposure Specific to Bites of Lutzomyia longipalpis, the Vector of Leishmania infantum chagasi in Latin America

Leishmania parasites are transmitted by the bite of an infected vector sand fly that injects salivary molecules into the host skin during feeding. Certain salivary molecules can produce antibodies and can be used as an indicator of exposure to a vector sand fly and potentially the disease it transmits. Here we identified potential markers of specific exposure to the sand fly Lutzomyia longipalpis, the vector of visceral leishmaniasis in Latin America. Initially, we determined which of the salivary proteins produce antibodies in humans, dogs, and foxes from areas endemic for the disease. To identify potential specific markers of vector exposure, we produced nine different recombinant salivary proteins from Lu. longipalpis and tested for their recognition by individuals exposed to another human-biting sand fly, Lu. intermedia, that transmits cutaneous leishmaniasis and commonly occurs in the same endemic areas as Lu. longipalpis. Two of the nine salivary proteins were recognized only by humans exposed to Lu. longipalpis, suggesting they are immunogenic proteins and may be useful in epidemiological studies. The identification of specific salivary proteins as potential markers of exposure to vector sand flies will increase our understanding of vector–human interaction, bring new insights to vector control, and in some instances act as an indicator for risk of acquiring disease

DETC Induces Leishmania Parasite Killing in Human In Vitro and Murine In Vivo Models: A Promising Therapeutic Alternative in Leishmaniasis

Background: Chemotherapy remains the primary tool for treatment and control of human leishmaniasis. However, currently available drugs present serious problems regarding side-effects, variable efficacy, and cost. Affordable and less toxic drugs are urgently needed for leishmaniasis. Methodology/Principal Findings: We demonstrate, by microscopy and viability assays, that superoxide dismutase inhibitor diethyldithiocarbamate (DETC) dose-dependently induces parasite killing (p,0.001) and is able to ??????sterilize?????? Leishmania amazonensis infection at 2 mM in human macrophages in vitro. We also show that DETC-induced superoxide production (p,0.001) and parasite destruction (p,0.05) were reverted by the addition of the antioxidant N-acetylcysteine, indicating that DETC-induced killing occurs through oxidative damage. Furthermore, ultrastructural analysis by electron microscopy demonstrates a rapid and highly selective destruction of amastigotes in the phagosome upon DETC treatment, without any apparent damage to the host cell, including its mitochondria. In addition, DETC significantly induced parasite killing in Leishmania promastigotes in axenic culture. In murine macrophages infected with Leishmania braziliensis, DETC significantly induced in vitro superoxide production (p = 0.0049) and parasite killing (p = 0.0043). In vivo treatment with DETC in BALB/C mice infected with Leishmania braziliensis caused a significant decrease in lesion size (p,0.0001), paralleled by a 100-fold decrease (p = 0.0087) in parasite burden. Conclusions/Significance: Due to its strong leishmanicidal effect in human macrophages in vitro, its in vivo effectiveness in a murine model, and its previously demonstrated in vivo safety profile in HIV treatment, DETC treatment might be considered as a valuable therapeutic option in human leishmaniasis, including HIV/Leishmania co-infection

An evaluation of factors associated with taking and responding positive to the tuberculin skin test in individuals with HIV/AIDS

<p>Abstract</p> <p>Background</p> <p>The tuberculin skin test (TST) is still the standard test for detecting latent infection by <it>M tuberculosis </it>(LTBI). Given that the Brazilian Health Ministry recommends that the treatment of latent tuberculosis (LTBI) should be guided by the TST results, the present study sets out to describe the coverage of administering the TST in people living with HIV at two referral health centers in the city of Recife, where TST is offered to all patients. In addition, factors associated with the non-application of the test and with positive TST results were also analyzed.</p> <p>Methods</p> <p>A cross-sectional study was carried out with HIV patients, aged 18 years or over, attending outpatient clinics at the Correia Picanço Hospital/SES/PE and the Oswaldo Cruz/UPE University Hospital, who had been recommended to take the TST, in the period between November 2007 and February 2010. Univariate and multivariate logistic regression analyses were carried out to establish associations between the dependent variable - taking the TST (yes/no), at a first stage analysis, and the independent variables, followed by a second stage analysis considering a positive TST as the dependent variable. The odds ratio was calculated as the measure of association and the confidence interval (CI) at 95% as the measure of accuracy of the estimate.</p> <p>Results</p> <p>Of the 2,290 patients recruited, 1087 (47.5%) took the TST. Of the 1,087 patients who took the tuberculin skin test, the prevalence of TST ≥ 5 mm was 21.6% among patients with CD4 ≥ 200 and 9.49% among those with CD4 < 200 (p = 0.002). The patients most likely not to take the test were: men, people aged under 39 years, people with low educational levels and crack users. The risk for not taking the TST was statiscally different for health service. Patients who presented better immunity (CD4 ≥ 200) were more than two and a half times more likely to test positive that those with higher levels of immunodeficiency (CD4 < 200).</p> <p>Conclusions</p> <p>Considering that the TST is recommended by the Brazilian health authorities, coverage for taking the test was very low. The most serious implication of this is that LTBI treatment was not carried out for the unidentified TST-positive patients, who may consequently go on to develop TB and eventually die.</p