Trypanosoma brucei gambiense group 2 experimental in vivo life cycle: from procyclic to bloodstream form.

Trypanosoma brucei gambiense (Tbg) group 2 is a subgroup of trypanosomes able to infect humans and is found in West and Central Africa. Unlike other agents causing sleeping sickness, such as Tbg group 1 and Trypanosoma brucei rhodesiense, Tbg2 lacks the typical molecular markers associated with resistance to human serum. Only 36 strains of Tbg2 have been documented, and therefore, very limited research has been conducted despite their zoonotic nature.

Tsetse fly ecology and risk of transmission of African trypanosomes related to a protected forest area at a military base in the city of Abidjan, Côte d'Ivoire.

African trypanosomoses, whose pathogens are transmitted by tsetse flies, are a threat to animal and human health. Tsetse flies observed at the military base of the French Forces in Côte d'Ivoire (FFCI base) were probably involved in the infection and death of military working dogs. Entomological and parasitological surveys were carried out during the rainy and dry seasons using "Vavoua" traps to identify tsetse fly species, their distribution, favorable biotopes and food sources, as well as the trypanosomes they harbor.

Sitosterolemia: Twenty Years of Discovery of the Function of .

Sitosterolemia is a lipid disorder characterized by the accumulation of dietary xenosterols in plasma and tissues caused by mutations in either or . encodes a pair of ABC half transporters that form a heterodimer (G5G8), which then traffics to the surface of hepatocytes and enterocytes and promotes the secretion of cholesterol and xenosterols into the bile and the intestinal lumen. We review the literature from the initial description of the disease, the discovery of its genetic basis, current therapy, and what has been learned from animal, cellular, and molecular investigations of the transporter in the twenty years since its discovery.

Evolution of Gene Expression during a Transition from Environmental to Genetic Sex Determination.

Genetic sex determination (GSD) can evolve from environmental sex determination (ESD) via an intermediate state in which both coexist in the same population. Such mixed populations are found in the crustacean Daphnia magna, where non-male producers (NMP, genetically determined females) coexist with male producers (MP), in which male production is environmentally inducible and can also artificially be triggered by exposure to juvenile hormone. This makes Daphnia magna a rare model species for the study of evolutionary transitions from ESD to GSD.

Long-term prevalence data reveals spillover dynamics in a multi-host (Artemia), multi-parasite (Microsporidia) community.

In the study of multi-host parasites, it is often found that host species contribute asymmetrically to parasite transmission. Yet in natural populations, identifying which hosts contribute to parasite transmission and maintenance is a recurring challenge. Here, we approach this issue by taking advantage of natural variation in the composition of a host community.

Sexual selection and inbreeding: Two efficient ways to limit the accumulation of deleterious mutations.

Theory and empirical data showed that two processes can boost selection against deleterious mutations, thus facilitating the purging of the mutation load: inbreeding, by exposing recessive deleterious alleles to selection in homozygous form, and sexual selection, by enhancing the relative reproductive success of males with small mutation loads. These processes tend to be mutually exclusive because sexual selection is reduced under mating systems that promote inbreeding, such as self-fertilization in hermaphrodites. We estimated the relative efficiency of inbreeding and sexual selection at purging the genetic load, using 50 generations of experimental evolution, in a hermaphroditic snail ().

Detecting Wahlund effects together with amplification problems: Cryptic species, null alleles and short allele dominance in Glossina pallidipes populations from Tanzania.

Population genetics is a convenient tool to study the population biology of non-model and hard to sample species. This is particularly true for parasites and vectors. Heterozygote deficits and/or linkage disequilibrium often occur in such studies and detecting the origin of those (Wahlund effect, reproductive system or amplification problems) is uneasy.

Bioinvasion Triggers Rapid Evolution of Life Histories in Freshwater Snails.

Biological invasions offer interesting situations for observing how novel interactions between closely related, formerly allopatric species may trigger phenotypic evolution in situ. Assuming that successful invaders are usually filtered to be competitively dominant, invasive and native species may follow different trajectories. Natives may evolve traits that minimize the negative impact of competition, while trait shifts in invasives should mostly reflect expansion dynamics, through selection for colonization ability and transiently enhanced mutation load at the colonization front.

Schmallenberg virus in Culicoides Latreille (Diptera: Ceratopogonidae) populations in France during 2011-2012 outbreak.

Following the emergence of the Schmallenberg virus (SBV) in 2011 in Germany and its rapid spread in Europe, Culicoides (Diptera: Ceratopogonidae) collected through the French surveillance network were analysed in order to record the presence of virus genome into species diversity collected, to assess the minimum infectious rates (MIR) and the virus circulation dynamics in Culicoides populations. Two vector activity periods were selected (2011, August to October, 53 sites and 2012, June to October, 35 sites) corresponding to 704 night collections. A total of 29,285 individual midges covering at least 50 species were tested either in pools of maximum 50 females or individually (for Culicoides obsoletus/Culicoides scoticus) using real-time RT-PCR.

Experimental Evidence for the Negative Effects of Self-Fertilization on the Adaptive Potential of Populations.

Self-fertilization is widely believed to be an "evolutionary dead end" [1, 2], increasing the risk of extinction [3] and the accumulation of deleterious mutations in genomes [4]. Strikingly, while the failure to adapt has always been central to the dead-end hypothesis [1, 2], there are no quantitative genetic selection experiments comparing the response to positive selection in selfing versus outcrossing populations. Here we studied the response to selection on a morphological trait in laboratory populations of a hermaphroditic, self-fertile snail under either selfing or outcrossing.

Colonization of the Mediterranean basin by the vector biting midge species Culicoides imicola: an old story.

Understanding the demographic history and genetic make-up of colonizing species is critical for inferring population sources and colonization routes. This is of main interest for designing accurate control measures in areas newly colonized by vector species of economically important pathogens. The biting midge Culicoides imicola is a major vector of orbiviruses to livestock.

Automixis in Artemia: solving a century-old controversy.

Parthenogenesis (reproduction through unfertilized eggs) encompasses a variety of reproduction modes with (automixis) or without (apomixis) meiosis. Different modes of automixis have very different genetic and evolutionary consequences but can be particularly difficult to tease apart. In this study, we propose a new method to discriminate different types of automixis from population-level genetic data.

Cryptic microsporidian parasites differentially affect invasive and native Artemia spp.

We investigated the host specificity of two cryptic microsporidian species (Anostracospora rigaudi and Enterocytospora artemiae) infecting invasive (Artemia franciscana) and native (Artemia parthenogenetica) hosts in sympatry. Anostracospora rigaudi was on average four times more prevalent in the native host, whereas E. artemiae was three times more prevalent in the invasive host.

Variation in habitat connectivity generates positive correlations between species and genetic diversity in a metacommunity.

An increasing number of studies are simultaneously investigating species diversity (SD) and genetic diversity (GD) in the same systems, looking for 'species- genetic diversity correlations' (SGDCs). From negative to positive SGDCs have been reported, but studies have generally not quantified the processes underlying these correlations. They were also mostly conducted at large biogeographical scales or in recently degraded habitats.

Cytological, molecular and life cycle characterization of Anostracospora rigaudi n. g., n. sp. and Enterocytospora artemiae n. g., n. sp., two new microsporidian parasites infecting gut tissues of the brine shrimp Artemia.

Two new microsporidia, Anostracospora rigaudi n. g., n.

Why join groups? Lessons from parasite-manipulated Artemia.

Grouping behaviours (e.g. schooling, shoaling and swarming) are commonly explicated through adaptive hypotheses such as protection against predation, access to mates or improved foraging.