The External Morphology of the Eggs of Culex (Culex) saltanensis (Diptera: Culicidae) Under Scanning Electron Microscopy.

The aim of the present study was to describe the morphology of the eggs of Culex (Culex) saltanensis Dyar that occurs in the Neotropical region. Eggs of the Cx. (Cux.) saltanensis were collected at the Mata Atlântica FIOCRUZ campus, fixed in 1% osmium tetroxide, prepared for mounting on metal supports, observed under a scanning electron microscope, and described morphologically. The eggs had a coniform shape with a length of approximately 0.5 mm (505-510 µm) and a width in the median portion of 117 µm (113-123 µm). Upper portion is lined with tubers of irregular shape and varying sizes (0.64-1.31 µm), located on a cross-linked matrix forming bands observed under optical microscopy. The micropyle is encased in a necklace of approximately 6.6-µm plates arranged in a flower-like shape. Comparing Cx. (Cux.) saltanensis eggs with several species of different genera, important divergent characteristics can be observed. However, this study points to the need for new descriptions of eggs of species belonging to the same subgenus in order to analyze if there will be differences between them. Culex (Cux.) saltanensis eggs have particular characteristics not observed in eggs of other Culicidae genera.

Comparing the egg ultrastructure of three Psorophora ferox (Diptera: Culicidae) populations / Comparação da ultraestrutura de ovos de três populações de Psorophora ferox (Diptera: Culicidae)

Abstract Characterising the external morphology of mosquito eggs is important, since it facilitates the identification of material from breeding sites and contributes to the understanding of species biology and group systematics. Therefore, was to compare eggs from different Psorophora ferox populations using scanning electron microscopy (SEM). Eggs were obtained from adult female of Ps. ferox collected in the Poços das Antas Biological Reserve (Reserva Biológica de Poços das Antas, Rio de Janeiro, Brazil). From each female, one portion of eggs (n = 5) was reared for identification purposes, and the second portion (n = 10) was examined using SEM for morphometric analysis. The egg morphology was then compared to that of eggs from Ps. ferox populations in Florida (USA) and Arena (Trinidad). The exochorion ornamentation of the populations differs considerably in the morphology of the tubercles of the chorionic cells, external chorionic reticulum, micropylar collar, and micropyle.

Resumo Caracterização da morfologia externa dos ovos do mosquito é importante, uma vez que facilita a identificação de materiais a partir de locais de reprodução e contribui para a compreensão da biologia das espécies e sistemática do grupo. O objetivo do presente estudo foi comparar os ovos de diferentes populações Psorophora ferox usando MEV. Os ovos foram obtidos a partir de fêmeas de Ps. ferox que foram coletadas na Reserva Biológica de Poço das Antas (Reserva Biológica de Poço das Antas, Rio de Janeiro, Brasil). A partir de cada fêmea, uma parte dos ovos (n = 5) foi criado para fins de identificação, e uma segunda parte (n = 10) foi examinado usando MEV para análise morfométrica. Foi então comparada a morfologia dos ovos de populações de Ps.ferox da Flórida (EUA) e Arena (Trinidad). A ornamentação do exocório das populações difere consideravelmente na morfologia dos tubérculos das células coriônicas, retículo coriônico externo, colar micropilar e micrópila.

Comparing the egg ultrastructure of three Psorophora ferox (Diptera: Culicidae) populations.

Characterising the external morphology of mosquito eggs is important, since it facilitates the identification of material from breeding sites and contributes to the understanding of species biology and group systematics. Therefore, was to compare eggs from different Psorophora ferox populations using scanning electron microscopy (SEM). Eggs were obtained from adult female of Ps. ferox collected in the Poços das Antas Biological Reserve (Reserva Biológica de Poços das Antas, Rio de Janeiro, Brazil). From each female, one portion of eggs (n = 5) was reared for identification purposes, and the second portion (n = 10) was examined using SEM for morphometric analysis. The egg morphology was then compared to that of eggs from Ps. ferox populations in Florida (USA) and Arena (Trinidad). The exochorion ornamentation of the populations differs considerably in the morphology of the tubercles of the chorionic cells, external chorionic reticulum, micropylar collar, and micropyle.

Sperm dimorphism in the Triatoma brasiliensis species complex and its applications.

Morphological and structural features of the sperm of the Triatoma brasiliensis Neiva, 1911 (Hemiptera: Reduviidae) species complex were examined in this first study investigating the sperm of Heteroptera and the genus Triatoma. Males were dissected and their seminal vesicles removed. For measurement, seminal vesicles were squashed on glass slides, spread, fixed and observed under a photomicroscope. The images were analysed and measures of sperm were made. Data were analysed using one-way analysis of variance and Tukey's test to detect differentiation among taxa. Furthermore, seminal vesicles were prepared for studies of transmission electron microscopy. All taxa studied showed polymorphic (short and long) sperm. The sperm of Triatoma brasiliensis macromelasoma was significantly longer (in total length) than that of the other four members of the complex, which supports the hypothesis of hybrid speciation of this member of the complex as an increase in the size of typical hybrids under heterosis was previously shown. The sperm cells of the five taxa have similar ultrastructural morphology. The ultrastructural features observed confirm the hypothesis, raised by previous studies, that they are synapomorphic to the suborder Heteroptera.

Penial morphology in three species of Brazilian tuco-tucos, Ctenomys torquatus, C. minutus, and C. flamarioni (Rodentia: Ctenomyidae).

The present study analyses the glans penis and baculum morphology of three Brazilian tuco-tucos, Ctenomys torquatus Lichtenstein, 1830, Ctenomys minutus Nehring, 1887 and Ctenomys flamarioni Travi, 1981, in order to identify possible variations and understand some more about this taxonomically complex group. We used fixed penis from 15 previously listed adult specimens. For a more detailed baculum analysis, the penis underwent dissection and diaphanisation, whereas to analyse the glans penis surface we used Scanning Electron Microscopy (SEM). Results showed striking differences in baculum morphology among the three species. While C. minutus have a particular V-shaped proximal baculum tip, C. flamarioni baculum is thin throughout the shaft with rounded proximal and distal tips. Ctenomys torquatus have a shorter and larger baculum, similar to what has previously been described for the species. Glans penis surface microstructure analyses also revealed inter-specific differences, with penial spines varying in shape, size and, especially density. Although C. torquatus has a relatively small penis, it has the largest penial spine density, which suggests a more complex penial ornamentation in this species.

Male reproductive system structure and accessory glands ultrastructure of two species of Triatoma (Hemiptera, Reduviidae, Triatominae).

Morphological studies in male reproductive system of insect, and accessory glands functions, can contribute to the knowledge of reproductive aspects in Triatominae. The present study aims to describe the structure of male reproductive system under scanning electron microscopy, and the ultrastructure of accessory glands during the process of maturation, in T. brasiliensis and T. melanica of different ages. These system consist of two testis, two vas deferens, two seminal vesicles, four pair of accessory glands and one ejaculatory duct. The four mesodermal male accessory glands of T. melanica and T. brasiliensis, present secretion storage in the first days of adult life in starved males. During the maturation process of male accessory glands of T. brasiliensis and T. melanica, granules with different sizes, shapes and electron density were seen. In T. melanica small vacuoles are released into the gland lumen in one-day-old males, however, after three and five days few granules are found in the cell cytoplasm. The secretory granules in T. brasiliensis increase in size and amount, in the five days old adult. The secretory pathway in the male accessory glands of the two species seems to be merocrine and apocrine suggesting that different substances are being produced at different times. The cell microvilli in T. brasiliensis are longer and narrower, these can be absent in some regions of the cell surface of T. melanica. Maturation of male accessory glands in the triatomine species studied occurred without adult blood meal. Its function can led to new insights for the comprehension of reproductive aspects in Triatominae.

Major cysteine protease (cruzipain) in Z3 sylvatic isolates of Trypanosoma cruzi from Rio de Janeiro, Brazil.

Trypanosoma cruzi, the etiologic agent of Chagas' disease, is represented by a set of parasites which circulate between man, vectors, domestic and wild animals. Recently, our group isolated from Triatoma vitticeps strains of T. cruzi that were characterized as belonging to the Z3 phylogenetic lineage. Since very little is known about the biological and/or biochemical markers of sylvatic Z3 isolates, we have studied the protein and protease profiles of distinct Z3 isolates designated as SMM10, SMM53, SMM88, and SMM98. By means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both quantitative and qualitative differences were observed in the protein profiles of these strains. All strains produced an acidic cysteine protease of 45 kDa, resembling cruzipain activity. The strain SMM10 synthesized an additional 55 kDa metalloprotease. Using Western blotting and anti-cruzipain antibody to detect cruzipain-like molecules, a 40-kDa reactive molecule was identified in all strains; in the strain SMM10, an 80-kDa protein was also reacted. Studies about cruzipain isoforms from sylvatic parasites could be valuable tools in the comprehension of the genetic variability in the pathogenesis of Chagas' disease.