de Souza. L.P., Silva, J.R.F., Araujo, A.M. and Camargo-Mathias M.I. 2013. Morphology of the female genital ducts of the blue land crab Cardisoma guanhumi (Crustacea: Brachyura: Gecarcinidae). -Acta Zoologica (Stockholm) 94: 300-307. This is a histological and histochemical analysis of the terminal portion of the female reproductive system and genital ducts of the blue land crab (Cardisoma guanhumi). Animals were collected in the Jaguaribe estuary (Ceará, Brazil) and dissected. Genital duct fragments were fixed and submitted to different staining techniques. The female reproductive system consists of a pair of ovaries and a pair of genital ducts. In the mid-posterior portion of each lobe, the ovaries communicate with the genital ducts, which are subdivided into oviduct, spermatheca, vagina, and gonopore. Histologically, the spermatheca of C. guanhumi is composed of columnar secretory epithelium and is divided into a dorsal zone and a ventral zone, the latter covered internally by a cuticle layer. Both zones are enveloped by a thin layer of loose connective tissue. Histological cross sections revealed the vagina to be concave, a pattern considered phylogenetically more advanced than the simple, tubular form. Our findings suggest fertilization is internal, favoring sperm from the most recent copulation.
Shinozaki-Mendes, R.A., Silva, J.R.F. and Hazin, F.H.V. 2012. Development of male reproductive system of the blue land crab Cardisoma guanhumi Latreille, 1828 (Decapoda: Gecarcinidae). -Acta Zoologica (Stockholm) 93: 390-399.In this study, the reproductive tract of the Cardisoma guanhumi was described both macroscopically and microscopically. The maturation stages of the reproductive system were defined, and the development of germ cells was described. The reproductive tract is made up of a pair of testis, a pair of vas deferentia, and a pair of ejaculatory ducts. The germ cells were classified in the order of development as spermatogonia (diameter: 10.5 ± 0.11 lm), spermatocytes (9.7 ± 0.07 lm), spermatids (initial phase: 5.5 ± 0.06 lm; final phase: 4.3 ± 0.05), and spermatozoa (SPZ) (4.0 ± 0.03 lm). The testis is made up of a germ zone, a maturation zone and collector ducts, which lead to the anterior vas deferens (AVD), containing solely SPZ. The spermatophores (SPH) start to be formed in the AVD, through the secretion of spermatophoric and protein matrices. In the median vas deferens, the SPH, already fully formed, are stored, while in the posterior vas deferens, a large production of a glycoprotein matrix is observed. Based on macroscopic and microscopic description of the male reproductive tract, three maturation stages are proposed: immature, maturing, and mature. Acta Zoologica (Stockholm) 93: 390-399 (October 2012) Shinozaki-Mendes et al. • Male reproductive system of the blue land crab
Abstract Bezerra, L. E. A., Silva, J. R. F., Carvalho, A. F. U. and Melo, V. M. M. 2006. Histological description of the ink gland of the tropical sea hare Aplysia dactylomela Rang, 1828. -Acta Zoologica (Stockholm) 87 : 203-207.This work describes for the first time the ink gland of Aplysia dactylomela Rang, 1828 using light microscopy and histochemical tests. The results reveal that this organ is covered by a layer of simple epithelium and that there are some differences between the epithelium facing the mantle shelf and that facing the mantle cavity. The former consists of columnar cells, which may have a secretory function, whereas the latter is a cuboidal epithelium. Underneath the epithelium and along the whole gland there are fibres of smooth muscle and collagen, organized in groups of parallel bundles. There are vesicles of different diameters, apparently with similar morphology. Some are filled with ink, whereas others are either granular or clear. The ink is released through a duct formed by invaginations of the cuboidal epithelium. Tests with bromophenol blue and periodic acid Schiff indicated that the ink and granulated vesicles contain proteins and carbohydrates or maybe glycoproteins. Between the fibre bundles and the vesicles there are dispersed cells. A diagram is presented emphasizing the covering epithelium, the distribution of muscle and collagen fibres, the dispersed cells, vesicles and ducts. This organization is similar to that of the other Aplysia species studied to date, A . californica .
While viviparity confers protection to the embryos during gestation, it increases energetic costs for the mother, which acquires new relations to its offspring. Maternal–fetal transfer of nutrients can occur in different patterns: as lecithotrophy (nourished by yolk) or matrotrophy (nourished by the mother). The development of Poecilia vivipara embryos was described macroscopically and microscopically, and the form of nutritional provisioning was identified. Embryonic development was divided into three prefertilization and seven postfertilization stages. The first organ to appear is the notochord, followed by the nervous, digestive and cardiovascular systems, and then by muscles and eyes. Embryonic nutritional provisioning was lecithotrophic, with yolk persisting until the last developmental stages and rich in proteins and polysaccharides. This kind of embryonic nutrition confirms the pattern found in the family Poeciliidae.
The production, distribution and use of electricity can generate low frequency electric and magnetic fields (50-60 Hz). Considering that some studies showed adverse effects on pancreatic β-cells exposed to these fields; the present study aimed to analyze the effects of 60 Hz electric fields on membrane potential during the silent and burst phases in pancreatic β-cells using a mathematical model. Sinusoidal 60 Hz electric fields with amplitude ranging from 0.5 to 4 mV were applied on pancreatic β-cells model. The sinusoidal electric field changed burst duration, inter-burst intervals (silent phase) and spike sizes. The parameters above presented dose-dependent response with the voltage amplitude applied. In conclusion, theoretical analyses showed that a 60 Hz electric field with low amplitudes changes the membrane potential in pancreatic β-cells.
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