Cytogenetic study in sand spiders (Sicariidae) from the brazilian Caatinga: sex chromosome system diversity in closely related species / Estudio citogenético en arañas de arena (Sicariidae) de la Caatinga brasileña: diversidad del sistema de cromosomas sexuales en especies estrechamente relacionadas

ABSTRACT In this study, we investigated the chromosomes of three species of Sicarius spiders from the Brazilian Caatinga, using classical and molecular cytogenetic techniques. Based on the phylogenetic approach, we also discussed about the variation of diploid number, types of sex chromosome system and changes in the localization of ribosomal genes of Scytodoidea. Sicarius are Synspermiata spiders that together with the genera Loxosceles and Hexophthalma constitute the family Sicariidae. In this group, the available cytogenetic data showed a low diploid number range (2n♂=18 to 2n♂=23) and the presence of only multiple sex chromosome systems (X1X2Y and X1X20). Mitotic metaphase cells exhibited 2n♂=16+X1X2Y for Sicarius cariri and S. ornatus, and 2n♂=18+XY for S. tropicus. In these species, silver impregnation revealed nucleolar organizer region (Ag-NOR) on the terminal region of pair 1. In S. ornatus and S. tropicus, the results obtained with fluorescent in situ hybridization (FISH) using 18S rDNA probe were similar to Ag-NOR, however in S. cariri, the ribosomal sites were localized in the terminal region of the X1 sex chromosome. In this work, we presented the first description of a simple sex chromosome system for Sicariidae, helping to understand how the XY sex chromosome system evolved from the X1X2Y system. Additionally, FISH data incongruous with Ag-NOR indicate that the cytogenetic studies in Sicariidae allow investigating the relation between the karyotype evolution and the distribution and the activity of rDNA genes.

RESUMEN En este estudio, investigamos los cromosomas de tres especies de arañas Sicarius de la Caatinga brasileña, utilizando técnicas de citogenética clásica y molecular. Usando un enfoque filogenético, también discutimos la variación del número diploide, los tipos de sistema cromosómico sexual y los cambios en la localización de los genes ribosómicos en Scytodoidea. Los Sicarius son arañas Synspermiata que, junto con los géneros Loxosceles y Hexophthalma, constituyen a la familia Sicariidae. En este grupo, los datos citogenéticos disponibles mostraron un rango de número diploide bajo (2n♂=18 a 2n♂=23) y únicamente la presencia de sistemas de cromosomas sexuales múltiples (X1X2Y y X1X20). Las células mitóticas en metafase mostraron 2n♂=16+X1X2Y para Sicarius cariri y S. ornatus, y 2n♂=18+XY para S. tropicus. En estas especies, la impregnación de plata reveló la región organizadora nucleolar (Ag-NOR) en la región terminal del par 1. En S. ornatus y S. tropicus, los resultados obtenidos con la hibridación in situ fluorescente (FISH) utilizando la sonda de ADNr 18S fueron similares a los de Ag-NOR, sin embargo, en S. cariri los sitios ribosomales se localizaron en la región terminal del cromosoma sexual X1. En este trabajo, presentamos la primera descripción de un sistema cromosómico sexual simple para Sicariidae, ayudando a entender cómo el sistema cromosómico sexual XY evolucionó a partir del sistema X1X2Y. Además, los datos de FISH incongruentes con Ag-NOR indican que los estudios citogenéticos en Sicariidae permiten investigar la relación entre la evolución del cariotipo y la distribución y la actividad de los genes de ADNr.

Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.(AU)

Heterophilic antibodies in sera from individuals without loxoscelism cross-react with phospholipase D from the venom of Loxosceles and Sicarius spiders

Background Loxoscelism is a severe human envenomation caused by Loxosceles spider venom. To the best of our knowledge, no study has evaluated the presence of antibodies against Loxosceles venom in loxoscelism patients without treatment with antivenom immunotherapy. We perform a comparative analysis for the presence of antibodies capable of recognizing Loxosceles venom in a group of patients diagnosed with loxoscelism and in a group of people without loxoscelism. Methods The detection of L. laeta venom, Sicarius venom and recombinant phospholipases D from Loxosceles (PLDs) in sera from people with loxoscelism (Group 1) and from healthy people with no history of loxoscelism (Group 2) was evaluated using immuno-dot blot, indirect ELISA, and Western blot. Results We found naturally heterophilic antibodies (IgG-type) in people without contact with Loxosceles spiders or any clinical history of loxoscelism. Either serum pools or single sera from Group 1 and Group 2 analyzed by dot blot tested positive for L. laeta venom. Indirect ELISA for venom recognition showed titles of 1:320 for Group 1 sera and 1:160 for Group 2 sera. Total IgG quantification showed no difference in sera from both groups. Pooled sera and purified IgG from sera of both groups revealed venom proteins between 25 and 32 kDa and the recombinant phospholipase D isoform 1 (rLlPLD1), specifically. Moreover, heterophile antibodies cross-react with PLDs from other Loxosceles species and the venom of Sicarius spider. Conclusions People without contact with the spider venom produced heterophilic antibodies capable of generating a cross-reaction against the venom of L. laeta and Sicarius spiders. Their presence and possible interference should be considered in the development of immunoassays for Loxosceles venom detection.

Sicarius uncinipenis and Deletrocephalus cesarpintoi in captive greater rheas of Minas Gerais State, Brazil / Sicarius uncinipenis e Deletrocephalus cesarpintoi em emas de cativeiro no Estado de Minas Gerais, Brazil

The present study details the pathological and parasitological findings of parasitic ventriculitis and nematode infections in the large intestines of two female Rhea americana americana birds. The birds were housed in captivity, and both exhibited poor body condition and lethargy. The rheas were sent to the Veterinary Hospital of the Veterinary School, Universidade Federal de Minas Gerais (UFMG) and, despite medical care, the clinical condition of the birds did not improve. The birds died two days after admission, and were submitted to necropsy. Gross, histopathology and parasitological analysis resulted in the identification of Sicarius uncinipenis, which is associated with parasitic ventriculitis, while Deletrocephalus cesarpintoi was identified in the large intestine of both rheas. The apparent clinical indications, including loss of appetite and death, combined with the discovery of numerous parasites and other pathology changes, supported the conclusion that the death of the birds was caused by the parasitic infection. Further investigations of these infections in free-living and captive rheas are required, such that accurate data on the incidence and pathogenicity of these parasites can be obtained.

O presente estudo relata os achados patológicos e parasitológicos de ventriculite parasitária e da infecção por nematódeo no intestino grosso em duas fêmeas Rhea americana americana. As aves eram mantidas em cativeiro e ambas apresentaram condição corporal ruim e inapetência. As emas foram encaminhadas para o Hospital Veterinário da Escola de Veterinária da UFMG e, apesar dos cuidados médicos, não houve melhora na condição clínica. As aves morreram dois dias após a internação e foram encaminhadas para a necropsia. Ao exame macroscópico, histopatológico e parasitológico, Sicarius uncinipenis foi identificado e associado com ventriculite parasitária, enquanto Deletrocephalus cesarpintoi foi identificado no intestino grosso. Possivelmente, o quadro de inapetência e morte foi causado pela infecção parasitária, pois os parasitos eram numerosos. Mais investigações dessa infecção são necessárias em emas de vida livre e cativeiro, para a obtenção de informações mais precisas da incidência e patogenicidade desses parasitos.