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Understanding geographic patterns of interaction between hosts and parasites can provide useful insight into the evolutionary history of the organisms involved. However, poor taxon sampling often hinders meaningful phylogenetic descriptions of groups of parasites. Trypanosome parasites that constitute the Trypanosoma cruzi clade are worldwide distributed infecting several mammalian species, especially bats. Diversity in this clade has been recently expanded by newly discovered species, but the common ancestor and geographical origins of this group of blood parasites are still debated. We present here results based on the molecular characterization of trypanosome isolates obtained from 1493 bats representing 74 species and sampled over 16 countries across four continents. After estimating the appropriate number of hypothetical species in our data set using GMYC models in combination with Poisson Tree Processes (mPTP) and ABGD, the 18S rRNA and gGAPDH genes were used for phylogenetic analyses to infer the major evolutionary relationships in the T. cruzi clade. Then, biogeographical processes influencing the distribution of this cosmopolitan group of parasites was inferred using BioGeoBEARS. Results revealed a large lineages diversity and the presence of trypanosomes in all sampled regions which infected 344 individuals from 31 bat species. We found eight Trypanosoma species, including: five previously known; one subspecies of Trypanosoma livingstonei (Trypanosoma cf. livingstonei); and two undescribed taxa (Trypanosoma sp. 1, Trypanosoma sp. 2), which were found exclusively in bats of the genus Miniopterus from Europe and Africa. The new taxa discovered have both an unexpected position in the global phylogeny of the T. cruzi clade. Trypanosoma sp. 1 is a sister lineage of T. livingstonei which is located at the base of the tree, whereas Trypanosoma sp. 2 is a sister lineage of the Shizotrypanum subclade that contains T. c. cruzi and T. dionisii. Ancestral areas reconstruction provided evidence that trypanosomes of the T. cruzi clade have radiated from Africa through several dispersion events across the world. We discuss the impact of these findings on the biogeography and taxonomy of this important clade of parasites and question the role played by bats, especially those from the genus Miniopterus, on the dispersal of these protozoan parasites between continents., (Copyright © 2019 Elsevier Inc. All rights reserved.)

We investigated the functional role of the Leishmania histone H1 and demonstrate for the first time that addition of histone H1 has a strong effect on microccocal digestion, chromatin condensation of parasite nuclei and that its overexpression can modulate parasite infectivity in vivo.

In this study, the mature domains of type I (CPB) and type II (CPA) cysteine proteinases (CPs) of Leishmania infantum were expressed and their immunogenic properties defined using sera from active and recovered cases of human visceral leishmaniasis and sera from infected dogs. Immunoblotting and ELISA analysis indicated that a freeze/thaw extract of parasite antigens showed similar and intensive recognition in both active cases of human and dog sera but lower recognition in recovered human individuals. The total IgG of actively infected human sera was higher than in recovered cases when rCPs were used as antigen. In contrast to dog sera, both active and recovered human cases have higher recognition toward rCPB than rCPA. Furthermore, the asymptomatic dogs in contrast to the symptomatic cases exhibited specific lymphocyte proliferation to both crude antigens and rCPs.

Chemokines constitute an expanding protein family of over 40 members which exhibit a wide variety of biological activities and are involved in many normal physiological processes, such as cellular migration, differentiation and activation, but also in pathological situations, such as inflammation and metastasis. Over the last few years, we have developed methods to manufacture long synthetic peptides of up to 130 residues, and to achieve the formation of native-like cysteine pairings. This ability prompted us to undertake the total chemical synthesis of chemokines. So far, we have successfully produced over 30 chemokine species, which exhibit biological activities similar to, or greater than, those reported by others. Chemical synthesis offers a clear advantage over recombinant technologies for the introduction of fluorochromes and haptens at molecularly defined positions. In addition, approval of chemically synthesized products for use in humans is straightforward compared with material produced by biological methods., (Copyright 2001 The International Association for Biologicals.)

Histone H1 in the parasitic protozoan Leishmania is a developmentally regulated protein encoded by the sw3 gene. Here we report that histone H1 variants exist in different Leishmania species and strains of L. major and that they are encoded by polymorphic genes. Amplification of the sw3 gene from the genome of three strains of L. major gave rise to different products in each strain, suggesting the presence of a multicopy gene family. In L. major, these genes were all restricted to a 50-kb Bg/II fragment found on a chromosomal band of 1.3 Mb (chromosome 27). The detection of RFLPs in this locus demonstrated its heterogeneity within several species and strains of Leishmania. Two different copies of sw3 (sw3.0 and sw3.1) were identified after screening a cosmid library containing L. major strain Friedlin genomic DNA. They were identical in their 5' UTRs and open reading frames, but differed in their 3' UTRs. With respect to the originally cloned copy of sw3 from L. major strain LV39, their open reading frames lacked a repeat unit of 9 amino acids. Immunoblots of L. guyanensis parasites transfected with these cosmids revealed that both copies could give rise to the histone H1 protein. The characterization of this locus will now make possible a detailed analysis of the function of histone H1 in Leishmania, as well as permit the dissection of the molecular mechanisms governing the developmental regulation of the sw3 gene.