Search results for "Parasite"

β-Catenin Signaling Drives Differentiation and Proinflammatory Function of IRF8-Dependent Dendritic Cells

2014

Abstract β-Catenin signaling has recently been tied to the emergence of tolerogenic dendritic cells (DCs). In this article, we demonstrate a novel role for β-catenin in directing DC subset development through IFN regulatory factor 8 (IRF8) activation. We found that splenic DC precursors express β-catenin, and DCs from mice with CD11c-specific constitutive β-catenin activation upregulated IRF8 through targeting of the Irf8 promoter, leading to in vivo expansion of IRF8-dependent CD8α+, plasmacytoid, and CD103+CD11b− DCs. β-Catenin–stabilized CD8α+ DCs secreted elevated IL-12 upon in vitro microbial stimulation, and pharmacological β-catenin inhibition blocked this response in wild-type cells…

Bacteria Associated with Copestylum (Diptera, Syrphidae) Larvae and Their Cactus Host Isolatocereus dumortieri

2011

We describe the gut bacterial diversity inhabiting two saprophagous syrphids and their breeding substrate (decayed tissues of the columnar cactus Isolatocereus dumortieri). We analyzed the gut microbiota of Copestylum latum (scooping larvae that feed on decayed cactus tissues) and Copestylum limbipenne (whose larvae can also feed on semiliquid tissues) using molecular techniques. DNA was extracted from larval guts and cactus tissues. The V1-V3 region of the 16S rRNA genes was amplified and sequenced. A total of 31079 sequences were obtained. The main findings are: C. limbipenne is dominated by several Enterobacteriaceae, including putative nitrogen-fixing genera and pectinolitic species and…

Heterogeneity of host-parasite relationships : ecological and evolution significance

2005

Although parasites have been studied for a long time, the major knowledge concern parasite which have medical or veterinary interest. Whereas they are omnipresent in the nature, the role of parasite infections on natural populations is poorly understood. One of the aim of this work was to study the pathogenicity of two groups of parasites (ticks and Haemosporidae) among natural populations of blackbirds. The study revealed that both parasites are associated with body condition and immune response. However, the study of an urban blackbird population did not confirm the effect of Haemosporidae on the survey and on the population dynamic.The impact of spatial pattern on the relation between ho…

Parasite assemblages of crucian carp (Carassius carassius) – is depauperate composition explained by lack of parasite exchange, extreme environmental…

2005

Recent studies on parasite communities have considered the factors which contribute to variability in parasite infections among populations of one host species. This paper examined parasite assemblages of crucian carp (Carassius carassius) in a natural set-up of two distinctive environments inhabited by the same host species and differing in respect to composition of other fish species: ponds, where extreme conditions prevent other fish species from occurring and lakes, where crucian carp coexist with other fish species. Our aim was to evaluate the significance of parasite exchange, environmental conditions and host suitability for the depauperate parasite assemblages observed in pond cruci…

Fish population size, and not density, as the determining factor of parasite infection: a case study.

2004

The diversity and abundance of parasites vary widely among populations of the same host species. These infection parameters are, to some extent, determined by characteristics of the host population or of its habitat. Recent studies have supported predictions derived from epidemiological models regarding the influence of host population density: parasite abundance and parasite species richness are expected to increase with increasing host population density, at least for directly transmitted parasites. Here, we test this prediction using a natural system in which populations of the crucian carp, Carassius carassius (L.), occur alone, with no other fish species, in a series of 9 isolated pond…

Permeabilization of the erythrocyte membrane with streptolysin O allows access to the vacuolar membrane of Plasmodium falciparum and a molecular anal…

1997

Protein sorting in Plasmodium falciparum-infected red blood cells permeabilized with the pore-forming protein streptolysin O

1996

Plasmodium falciparum is an intracellular parasite of human red blood cells (RBCs). Like many other intracellular parasites, P. falciparum resides and develops within a parasitophorous vacuole which is bound by a membrane that separates the host cell cytoplasm from the parasite surface. Some parasite proteins are secreted into the vacuolar space and others are secreted, by an as yet poorly defined pathway, into the RBC cytosol. The transport of proteins from the parasite has been followed mainly using morphological methods. In search of an experimental system that would allow (i) dissection of the individual steps involved in transport from the parasite surface into the RBC cytosol, and (ii…

Comparison of viability assays for Cryptosporidium parvum oocysts after disinfection.

2003

Abstract In order to test various viability assays for Cryptosporidium parvum oocysts were used to infect HCT-8 cells in vitro or baby mice. Infected cells were either stained with fluorescent anti- Cryptosporidium -antibody or lysed and subjected to C. parvum- specific PCR after 48 h. Titrations with infective oocysts were performed and compared to oocysts disinfected with Neopredisan © for 2 h at varying concentrations. Caecal smears and histological sections from infected animals were examined in parallel. The number of foci of parasite development in vitro after immunofluorescent staining correlated well with the infection dose. PCR was less quantifiable and the results were not always …

Differentiation of Type 1 ILCs from a Common Progenitor to All Helper-like Innate Lymphoid Cell Lineages

2014

SummaryInnate lymphoid cells (ILCs) are a recently recognized group of lymphocytes that have important functions in protecting epithelial barriers against infections and in maintaining organ homeostasis. ILCs have been categorized into three distinct groups, transcriptional circuitry and effector functions of which strikingly resemble the various T helper cell subsets. Here, we identify a common, Id2-expressing progenitor to all interleukin 7 receptor-expressing, “helper-like” ILC lineages, the CHILP. Interestingly, the CHILP differentiated into ILC2 and ILC3 lineages, but not into conventional natural killer (cNK) cells that have been considered an ILC1 subset. Instead, the CHILP gave rise…

Antiparasitic Effect of Stilbene and Terphenyl Compounds against Trypanosoma cruzi Parasites

2021

AbstractBackgroundChagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite Trypanosoma cruzi. No progress in the treatment of this pathology has been made since Nifurtimox was introduced more than fifty years ago and is considered very aggressive and may cause several adverse effects. Currently, this drug has severe limitations, including high frequency of undesirable side effects and limited efficacy and availability and the research to discover new drugs for the treatment of Chagas disease is imperative. Many drugs available in the market are natural products as found in nature or compounds designed based on the str…