Publications by authors named "Amanda Ravazi"

Morphological studies applied to the taxonomy of the Triatominae cover various structures (head, wing, thorax, genitalia, and eggs). Exochorial structures of hybrid eggs were characterized and compared with the parents, demonstrating that hybrids presented characteristics identical to the exochorial pattern observed in the females of the crosses, which resulted in the hypothesis that the pattern of triatomine eggs is possibly a characteristic inherited from females. Thus, we characterized the exochorium of the eggs of several triatomine hybrids and compared them with the parents, to assess the pattern of segregation and test the hypothesis of maternal inheritance.

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  • Hybridization among Triatoma species can affect their evolution and may lead to hybrid sterility, which is caused by gonadal dysgenesis (GD) or unviable gametes, but previous studies had not documented GD in triatomine hybrids.
  • This study performed reciprocal crosses between Triatoma longipennis and Triatoma mopan, and while hybrids were created from one specific cross, further intercrosses and backcrosses yielded no offspring, confirming sterility.
  • The findings revealed that the hybrids exhibited bilateral gonadal dysgenesis, with their male gonads being completely atrophied and devoid of germ cells, leading to the conclusion that GD is responsible for the observed sterility in these hybrids.
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Chagas disease affects about eight million people. In view of the issues related to the influence of anthropogenic changes in the dynamics of the distribution and reproductive interaction of triatomines, we performed experimental crosses between species of the Rhodniini tribe in order to evaluate interspecific reproductive interactions and hybrid production capacity. Reciprocal crossing experiments were conducted among , , , , ; × and × .

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Several cytogenetic studies have already been performed in Triatominae, such that different karyotypes could be characterized (ranging from 2n = 21 to 25 chromosomes), being the changes in the number of chromosomes related mainly to fusion and fission events. These changes have been associated with reproductive isolation and speciation events in other insect groups. Thus, we evaluated whether different karyotypes could act in the reproductive isolation of triatomines and we analyzed how the events of karyotypic evolution occurred along the diversification of these vectors.

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  • * The female genitalia of the hybrids displayed traits from both parent species, and cytogenetic analyses showed normal chromosome structures.
  • * Molecular studies linked the hybrids to both parent species through specific genetic markers, revealing similar feeding and defecation patterns as their parents.
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  • The geniculatus clade includes several species of triatomine bugs, some of which have been studied for their role in transmitting Chagas disease, but no natural hybrids have been previously documented among these species.
  • Experimental crossings between species within the megistus and lignarius groups were performed to assess reproductive compatibility; results showed no egg hatching, indicating prezygotic barriers and confirming specific distinctions among the species.
  • The findings suggest that while hybridization is possible in other triatomine groups, the geniculatus clade displays prezygotic barriers that prevent hybrid formation, suggesting its significance for evolutionary studies in this area.
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Background: Triatoma tibiamaculata is a species distributed in ten Brazilian states which has epidemiological importance as it has already been found infecting household areas. The taxonomy of this triatomine has been quite unstable: it was initially described as Eutriatoma tibiamaculata. Later, the species was transferred from the genus Eutriatoma to Triatoma.

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  • The study demonstrated that despite morphological similarities, distinct genetic and reproductive barriers exist between the species, confirming their separate identities.
  • Experimental crossbreeding between these species showed no hybridization, indicating prezygotic reproductive isolation.
  • The findings suggest that one species is the most evolved member of the complex, rather than just a chromatic variant of another.
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Background: Triatoma sordida is one of the main Chagas disease vectors in Brazil. In addition to Brazil, this species has already been reported in Bolivia, Argentina, Paraguay, and Uruguay. It is hypothesized that the insects currently identified as T.

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Triatomines are hematophagous insects of great epidemiological importance, since they are vectors of the protozoan Trypanosoma cruzi, the etiological agent of Chagas disease. Triatoma brasiliensis complex is a monophyletic group formed by two subspecies and six species: T. b.

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  • The taxonomy of the Meccus genus has changed multiple times since its first description in 1835, with recent studies supporting its synonymy with the Triatoma genus based on genetic evidence.
  • Natural hybridization among related species within the T. phyllosoma subcomplex has been confirmed, showing the potential for viable offspring across different species.
  • Experimental crosses between T. longipennis and T. mopan produced viable hybrids, indicating reproductive compatibility and supporting the reevaluation of species classification within the Triatominae subfamily.
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  • There are 156 species in the subfamily Triatominae, all potential vectors for Chagas disease, classified into 18 genera and five tribes, with Triatoma being a paraphyletic group.
  • The Triatoma brasiliensis complex, a monophyletic group, includes eight species, and experimental crosses among these species have been conducted to explore systematic and evolutionary questions.
  • The study found that hybrids displayed varying segregation patterns of phenotypic traits, emphasizing the need for integrative taxonomy to accurately identify Chagas disease vectors amid potential natural hybridization.
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  • All triatomine species are potential vectors for Chagas disease, but the genera Triatoma, Panstrongylus, and Rhodnius are particularly significant in understanding its epidemiology.
  • Cytogenetic analysis reveals that the species within the Rhodnius genus exhibit minimal chromosomal variation, prompting an examination of their chromatin and chromosome DNA composition.
  • Findings indicate that most Rhodnius species possess euchromatic autosomes without AT- and CG-rich blocks, and intriguing patterns of CG-rich heterochromatin suggest a unique evolutionary trajectory for specific groups within the genus.
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Chagas disease is the most prevalent neglected tropical disease in the Americas and makes an important contribution to morbidity and mortality rates in countries where it is endemic since 30 to 40% of patients develop cardiac diseases, gastrointestinal disorders, or both. In this paper, a new species of the genus is described based on specimens collected in the Department San Miguel, Province of Corrientes, Argentina. sp.

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Chagas disease is caused by the Trypanosoma cruzi and transmitted mainly by triatomines. Triatoma is a paraphyletic group and the species of this genus are grouped into complexes and subcomplexes. Morphological data and geographical distribution grouped initially T.

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The use of subtle features as species diagnostic traits in taxa with high morphological similarity sometimes fails in discriminating intraspecific variation from interspecific differences, leading to an incorrect species delimitation. A clear assessment of species boundaries is particularly relevant in disease vector organisms in order to understand epidemiological and evolutionary processes that affect transmission capacity. Here, we assess the validity of the recently described Rhodnius taquarussuensis (da Rosa et al.

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The genus within the subfamily Triatominae and tribe Rhodniini comprises the species , , and , all potential vectors of Chagas disease. A feature of is their close association with birds, which makes them an interesting model for evolutionary studies. We analyzed cytogenetically spp.

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Chagas disease is caused by and transmitted by feces of a triatomine that has the habit of defecating during blood feeding. The salivary glands of triatomines are important to hematophagy because their saliva is rich in anticoagulant and hemolytic proteins. The salivary glands of some species analyzed are reddish due to the presence of nitrophorins (antihemostatic activity).

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All species of triatomines are considered potential vectors of Chagas disease and the reproductive biology of these bugs has been studied by different approaches. In 1999, nucleolar persistence during meiosis was observed in the subfamily for the first time. Recently, it has been observed that all species within the genus Rhodnius exhibit the same phenomenon, suggesting that it may be a synapomorphy of the triatomines.

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The Triatominae subfamily is comprised of 18 genera and six tribes. The tribe Rhodniini is comprised of two genera (Rhodnius and Psammolestes). Nucleolar persistence is defined by the presence of the nucleolus or nucleolar corpuscles during the meiotic metaphase.

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