Coding-complete genome sequences of two bovine viral diarrhea virus 1a isolates from Uruguay.

Bovine viral diarrhea virus (BVDV) is an economically relevant pathogen affecting cattle production and reproduction worldwide. We report the coding-complete sequences of two BVDV-1a subtype isolates, circulating in Uruguay.

Survey of selected pathogens in free-ranging pinnipeds in Uruguay.

Marine mammals, regarded as sentinels of aquatic ecosystem health, are exposed to different pathogens and parasites under natural conditions. We surveyed live South American fur seals Arctocephalus australis and South American sea lions Otaria flavescens in Uruguay for Leptospira spp., canine distemper virus (CDV), Mycobacterium spp., Toxoplasma gondii, and Neospora caninum. Samples were collected from 2007 to 2013. The seroprevalence of Leptospira spp. was 37.6% positive, 50.9% negative, and 11.5% suspect for A. australis (n = 61) while for O. flavescens (n = 12) it was 67% positive, 25% negative, and 8% suspect. CDV RNA was not detected in any of the analyzed samples. Most animals tested seropositive to tuberculosis antigens by WiZo ELISA (A. australis: 29/30; O. flavescens: 20/20); reactivity varied with a novel ELISA test (antigens MPB70, MPB83, ESAT6 and MPB59). Seroprevalence against N. caninum and T. gondii was 6.7 and 13.3% positive for O. flavescens and 0 and 2.2% positive for A. australis respectively. To evaluate possible sources of infection for pinnipeds, wild rats Rattus rattus and semi-feral cats Felis catus were also tested for Leptospira spp. and T. gondii respectively. Water samples tested for Leptospira revealed saprofitic L. bioflexa. Pathogenic Leptospira were detected in the kidneys of 2 rats, and cats tested positive for T. gondii (100%). These results represent a substantial contribution to the study of the health status of wild pinnipeds in Uruguay.

Origin and spreading of canine morbillivirus in South America.

Canine distemper virus (CDV) is a Morbillivirus (Canine morbillivirus) that greatly impacts domestic and wildlife carnivores worldwide. The CDV RNA genome has high genetic variability, evidenced by several lineages that follow a global geographic pattern. The evolutionary trajectories and population dynamics of CDV lineages are still unclear and debatable, particularly in South America, where relatively few sequences are available. We performed phylogenetic and Bayesian analyses using an updated dataset of the highly variable hemagglutinin (H) gene, including seven South American countries. The time to the most recent common ancestor (tMRCA) of the current CDV lineages was dated to the early 1900s in North America. Maximum likelihood and Bayesian maximum clade credibility phylogenies showed similar topologies with two main branches (L1 and L2) corresponding to the NA1 lineage (L1) and the remaining lineages worldwide (L2). The four circulating lineages in South America (EU1/SA1, SA2, SA3, NA4/SA4) arose from independent migration events from North America and Europe. North American strains colonized most northern South American countries via Ecuador and then Colombia and Peru, originating the SA3 and NA4/SA4 lineages during their spread. The entry and expansion in the southern part of South America (Argentina, Brazil, Chile, and Uruguay) occurred through three independent migration events and gave rise to the EU1/SA1 and SA2 lineages. South American lineages have specific combinations of amino acids under positive selection that constitute signatures of taxonomic and evolutionary relevance. Our findings provide a comprehensive scenario for the origin and migration routes of Canine morbillivirus in South America and highlight the importance of phylodynamics in understanding the geographic patterns of modern genetic variability.

High chromosomal mobility of rDNA clusters in holocentric chromosomes of Triatominae, vectors of Chagas disease (Hemiptera-Reduviidae).

The subfamily Triatominae (Hemiptera-Reduviidae) includes more than 150 blood-sucking species, potential vectors of the protozoan Trypanosoma cruzi, causative agent of Chagas disease. A distinctive cytogenetic characteristic of this group is the presence of extremely stable chromosome numbers. Unexpectedly, the analyses of the chromosomal location of ribosomal gene clusters and other repetitive sequences place Triatominae as a significantly diverse hemipteran subfamily. Here, we advance the understanding of Triatominae chromosomal evolution through the analysis of the 45S rDNA cluster chromosomal location in 92 Triatominae species. We found the 45S rDNA clusters in one to four loci per haploid genome with different chromosomal patterns: On one or two autosomes, on one, two or three sex chromosomes, on the X chromosome plus one to three autosomes. The movement of 45S rDNA clusters is discussed in an evolutionary context. Our results illustrate that rDNA mobility has been relatively common in the past and in recent evolutionary history of the group. The high frequency of rDNA patterns involving autosomes and sex chromosomes among closely related species could affect genetic recombination and the viability of hybrid populations, which suggests that the mobility of rDNA clusters could be a driver of species diversification.

High dynamics of rDNA cluster location in kissing bug holocentric chromosomes (Triatominae, Heteroptera).

In this paper, we determine by fluorescent in situ hybridization the variability in the chromosomal location of 45S rDNA clusters in 38 species belonging to 7 genera of the Triatominae subfamily, using a triatomine-specific 18S rDNA probe. Our results show a striking variability at the inter- and intraspecific level, never reported so far in holocentric chromosomes, revealing the extraordinary genomic dynamics that occurred during the evolution in this group of insects. Our results also demonstrate that the chromosomal position of rDNA clusters is an important marker to disclose chromosomal differentiation in species karyotypically homogenous in their chromosome number.

Cytogenetics and genome evolution in the subfamily Triatominae (Hemiptera, Reduviidae).

The subfamily Triatominae (Hemiptera, Reduviidae), vectors of Chagas disease, includes over 140 species. Karyotypic information is currently available for 80 of these species. This paper summarizes the chromosomal variability of the subfamily and how it may reveal aspects of genome evolution in this group. The Triatominae present a highly conserved chromosome number. All species, except 3, present 20 autosomes. The differences in chromosome number are mainly caused by variation in the number of sex chromosomes, due to the existence of 3 sex systems in males (XY, X(1)X(2)Y and X(1)X(2)X(3)Y). However, inter- and intraspecific differences in the position, quantity and meiotic behavior of constitutive heterochromatin, in the total genome size, and in the location of ribosomal 45S rRNA clusters, have revealed considerable cytogenetic variability within the subfamily. This cytogenetic diversity offers the opportunity to perform cytotaxonomic and phylogenetic studies, as well as structural, evolutionary, and functional analyses of the genome. The imminent availability of the complete genome of Rhodnius prolixus also opens new perspectives for understanding the evolution and genome expression of triatomines. The application of fluorescence in situ hybridization for the mapping of genes and sequences, as well as comparative analyses of genome homology by comparative genomic hybridization will be useful tools for understanding the genomic changes in relation to evolutionary processes such as speciation and adaptation to different environments.

Meics, a novel zinc-finger protein which relocates from nuclei to the central meiotic spindle during Drosophila spermatogenesis.

A Drosophila gene encoding a novel zinc-finger protein, Meics, was cloned using a monoclonal antibody. The predicted amino acid sequence contains 12 zinc-finger motifs of the C2H2-type. During spermatogenesis, Meics distributes intranuclearly at pre- and post-meiotic stages whereas it relocates to central-spindle microtubules at both meiotic divisions.

Chromosome numbers in the Triatominae (Hemiptera-Reduviidae): a review.

The chromosome numbers of 46 out of the 122 currently recognized species of Triatominae (Hemiptera, Reduviidae) are summarized. We present the number of autosomes, the sex mechanism and the first reference for each karyotype.

Karyotype evolution in holocentric chromosomes of three related species of triatomines (Hemiptera-Reduviidae).

C-banded karyotypes, DNA content and the male meiiotic process of Triatoma platensis and Triatoma delpontei are compared with those of Triatoma infestans, the main vector of Chagas disease in South America. These three species present the same diploid chromosome number 2n = 22 (20 autosomes + XX male/XY female). They also have several cytogenetic traits that differ from all other triatomines: large autosomes, C-heterochromatic blocks and meiotic heteropycnotic chromocenters formed by autosomes and sex chromosomes. In spite of these similarities, each species presents different chromosomal behavior during male meiosis, distinct DNA content and a specific amount and localization of the C-heterochromatin. The differences in DNA content are mainly due to the variation in C-heterochromatin amount, which may be interpreted as loss and/or gain of C-regions. This interpretation is supported by the presence of meiotic and mitotic chromocenters that facilitate the transference of C-positive material. The cytogenetic data presented in this work suggest that T. infestans and T. platensis are more closely related to each other than to T. delpontei. It can also be inferred that the differences in distribution and amount of heterochromatin do not play a direct role in speciation in this group.

Cytogenetics as a tool for triatomine species distinction (Hemiptera-Reduviidae).

Several cytogenetic traits were tested as species diagnostic characters on five triatomine species: Rhodnius pictipes, R. nasutus, R. robustus, Triatoma matogrossensis and T. pseudomaculata. Four of them are described for the first time. The detailed analysis of the meiotic process and the application of C-banding allowed us to identify seven cytogenetic characters which result useful to characterize and differentiate triatomine species.