Search results for "Protozoa"
showing 10 items of 222 documents
Roles for RpoS in survival of Escherichia coli during protozoan predation and in reduced moisture conditions highlight its importance in soil environ…
2017
The soil is a complex ecosystem where interactions between biotic and abiotic factors determine the survival and fate of microbial inhabitants of the system. Having previously shown that Escherichia coli requires the general stress response regulator, RpoS, to survive long term in soil, it was important to determine what specific conditions in this environment necessitate a functional RpoS. This study investigated the susceptibility of soil-persistent E. coli to predation by the single-celled eukaryotes Acanthamoeba polyphaga and Tetrahymena pyriformis, and the role RpoS plays in resisting this predation. Strain-specific differences were observed in the predation of E. coli strains, with so…
A Short and Improved Synthesis of the Antiprotozoal Abietane Diterpenoid (–)-Sugikurojin A
2016
An efficient and straightforward semisynthesis of the antiprotozoal abietane diterpenoid (–)-sugikurojin A, starting from the readily available methyl ester of callitrisic acid (4-epi-dehydroabietic acid) isolated from sandarac resin, is reported. This optimized semisynthetic route provides a convenient source of the antiprotozoal compound, in four steps from methyl callitrisate in 50% overall yield, for further biological studies.
Biosynthesis of heme O in intraerythrocytic stages of Plasmodium falciparum and potential inhibitors of this pathway
2019
A number of antimalarial drugs interfere with the electron transport chain and heme-related reactions; however, the biosynthesis of heme derivatives in Plasmodium parasites has not been fully elucidated. Here, we characterized the steps that lead to the farnesylation of heme. After the identification of a gene encoding heme O synthase, we identified heme O synthesis in blood stage parasites through the incorporation of radioactive precursors. The presence of heme O synthesis in intraerythrocytic stages of Plasmodium falciparum was confirmed by mass spectrometry. Inabenfide and uniconazole–P appeared to interfere in heme synthesis, accordingly, parasite growth was also affected by the additi…
Comparison of hemolytic activity of the intermediate subunit of Entamoeba histolytica and Entamoeba dispar lectins.
2017
Galactose and N-acetyl-D-galactosamine-inhibitable lectin of Entamoeba histolytica has roles in pathogenicity and induction of protective immunity in rodent models of amoebiasis. Recently, the intermediate subunit of the lectin, Igl1, of E. histolytica has been shown to have hemolytic activity. However, the corresponding lectin is also expressed in a non-virulent species, Entamoeba dispar, and another subunit, Igl2, is expressed in the protozoa. Therefore, in this study, we compared the activities of Igl1 and Igl2 subunits from E. histolytica and E. dispar using various regions of recombinant Igl proteins expressed in Escherichia coli. The recombinant E. dispar Igl proteins had comparable h…
Prevalence of intestinal parasites, with emphasis on the molecular epidemiology of Giardia duodenalis and Blastocystis sp., in the Paranaguá Bay, Bra…
2018
BACKGROUND: Intestinal protozoan parasites are major contributors to the global burden of gastrointestinal disease causing significant socioeconomic consequences. Children living in resource-poor settings with restricted access to water and sanitary services are particularly at risk of these infections. METHODS: A prospective, community-based, cross-sectional survey was conducted in Paraná (southern Brazil) between May 2015 and May 2016. A total of 766 stool samples were individually collected from volunteers (male/female ratio: 0.99; age range: 0-76 years) and used for investigating the presence of intestinal helminth and protozoan species by routine microscopic procedures including the Ka…
Risk factors for anthroponotic cutaneous leishmaniasis in unresponsive and responsive patients in a major focus, southeast of Iran
2018
Cutaneous leishmaniasis (CL) is a serious health challenge at the global level due to Leishmania tropica. This study was conducted to evaluate the risk factors associated with anthroponotic CL (ACL) in unresponsive (patient who does not heal and remains with an active lesion, despite receiving two courses of intra-lesional Glucantime along with cryotherapy and one cycle of systemic Glucantime) and responsive patients in a major focus in southeastern Iran. A case-control study was conducted from April 2015 to October 2016 in the southeast of Iran. Patients were recruited in a major ACL focus from unresponsive and responsive cases. These patients were compared for environmental, clinical, and…
In vitro antileishmanial activity of trans-stilbene and terphenyl compounds
2016
Leishmaniasis are globally widespread parasitic diseases which often leads to death if left untreated. Currently available drugs present different drawbacks, so there is an urgent need to develop new, safe and cost-effective drugs against leishmaniasis. In this study we tested a small library of trans-stilbene and terphenyl derivatives against promastigote, amastigotes and intramacrophage amastigote forms of Leishmania infantum. Two compounds of the series, the trans-stilbene 3 and the terphenyl 11, presented the best activity and safety profiles. Terphenyl 11 showed a leshmanicidal activity higher than pentostam and the ability to induce apoptosis selectively in Leishmania infantum while s…
Significance of chronic toxoplasmosis in epidemiology of road traffic accidents in Russian Federation
2017
Studies carried out in Moscow residents have revealed that the prevalence of chronic toxoplasmosis is very close to those in countries of Eastern and Central Europe. Our findings also demonstrated a statistically significant relationship between the rate of traffic accidents and the seroprevalence of chronic toxoplasmosis in drivers who were held responsible for accidents. The latter was 2.37 times higher in drivers who were involved in road accidents compared with control groups. These results suggest that the consequences of chronic toxoplasmosis (particularly a slower reaction time and decreased concentration) might contribute to the peculiarities of the epidemiology of road traffic acci…
Performance of a rapid diagnostic test for the detection of Cryptosporidium spp. in African children admitted to hospital with diarrhea
2020
Background Cryptosporidium is a protozoan parasite that causes mild to severe diarrhoeal disease in humans. To date, several commercial companies have developed rapid immunoassays for the detection of Cryptosporidium infection. However, the challenge is to identify an accurate, simple and rapid diagnostic tool for the estimation of cryptosporidiosis burden. This study aims at evaluating the accuracy of CerTest Crypto, a commercialized rapid diagnostic test (RDT) for the detection of Cryptosporidium antigens in the stool of children presenting with diarrhoea. Methods A cross-sectional study was conducted in four study sites in Sub-Saharan Africa (Gabon, Ghana, Madagascar, and Tanzania), from…
Disease severity in patients with visceral leishmaniasis is not altered by co-infection with intestinal parasites
2017
Visceral leishmaniasis (VL) is a neglected tropical disease that affects the poorest communities and can cause substantial morbidity and mortality. Visceral leishmaniasis is characterized by the presence of Leishmania parasites in the spleen, liver and bone marrow, hepatosplenomegaly, pancytopenia, prolonged fever, systemic inflammation and low body mass index (BMI). The factors impacting on the severity of VL are poorly characterized. Here we performed a cross-sectional study to assess whether co-infection of VL patients with intestinal parasites influences disease severity, assessed with clinical and haematological data, inflammation, cytokine profiles and BMI. Data from VL patients was s…