Navegando por Assunto "Ultraestrutura"

Agora exibindo 1 - 10 de 10

Acesso aberto (Open Access)
Aspectos ultraestruturais do espermatozóide de Natica marochiensish (Gmelin) (Mollusca, Gastropoda) do litoral norte do Brasil
(1997-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CASAL, Graça Maria Figueiredo; AZEVEDO, Carlos José Correia de
Spermatozoa of Natica marochienssish (Gmelin, 1791) is described by light and electron microscopy. The spermatozoon is of the primitive type with head contains a conical acrosomal complex with an acrosomal vesicle of dense matrix having a basis occupied by the subacrosomal space. The middle piece shows the centriolar complex surrounded by mitochondria and the tail contains the axoneme with a 9+2.
Acesso aberto (Open Access)
Estrutura fina do espermatozóide de Acestrorhynchus falcatus Bloch (Teleostei, Characidae) da região norte do Brasil
(2000-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CORRAL, Laura Felícia Machado; AZEVEDO, Carlos José Correia de
Spermatozoa of amazon fish, Acestrorhynchus falcatus Bloch, 1794 were investigated by optical microscopy (DIC) and electron microscopy (TEM). Spermatozoa have no acrosome, the head is ovoid, and the midpiece region cylindrical, contains spherical mitochondria. The centriolar complex is located at the lateral side of the nucleus, formed by nine peripheral pairs of microtubules and arranged in a right angle to each other. The flagellum consists of nine pairs of peripheral and two central microtubules.
Acesso aberto (Open Access)
Estrutura fina do espermatozóide de Mellita quinquiesperforata Leske (Echinodermata) do litoral norte do Brasil
(2000-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CORRAL, Laura Felícia Machado; AZEVEDO, Carlos José Correia de
The fine structure of the spermatozoon in the Mellita quinquiesperforata Leske, 1778 was studied. Collected from the Amazon region, were described by light and transmission electron microscopy. The spermatozoon consisted of a acrosome complex, nucleus, four to six mitochondria, two centrioles and flagellum. The acrosome was composed of a acrosome complex, the acrosomal vesicle and the subacrosomal space. The nucleus are composed by dense material. The middle piece contains 4-6 mitochondria which are arranged around the centrioles, the 9p+0, whose axoneme has the classic 9p+2 microtubular construction.
Acesso aberto (Open Access)
Estrutura fina do espermatozóide de Tagelus plebeius (Lightfoot) (Mollusca, Bivalvia) do litoral norte do Brasil
(1997-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CASAL, Graça Maria Figueiredo; AZEVEDO, Carlos José Correia de
It is described the sperm ultraestructure differentiation during spermiogenesis of Tagelus plebeius (Lightfoot, 1786). The spermatozoon is an uniflagellated cell of the primitive type. The head region contains a rounded or conical nucleus surrounded by acrosome. The middle piece contains four mitochondria which are arranged around the axoneme. The flagellum contains the usual microtubular axoneme.
Acesso aberto (Open Access)
Light and electron microscopy of Myxobolus sciades n. sp. (Myxozoa), a parasite of the gills of the Brazilian fish Sciades herzbergii (Block, 1794) (Teleostei: Ariidae)
(2010-03) AZEVEDO, Carlos José Correia de; CASAL, Graça Maria Figueiredo; MENDONÇA, Ivete Lopes de; CARVALHO, Erisson; MATOS, Patrícia Santos; MATOS, Edilson Rodrigues
A myxosporean parasite in the gill lamellae of the freshwater teleost fish, Sciades herzbergii (Ariidae) (Block, 1794), from the Poti River (Northeast of Brazil) was described by light and electron microscopy studies. Polysporic histozoic cyst-like plasmodia containing several life-cycle stages, including mature spores, were observed. The spores were pyriform and uninucleate, measuring 9.15 ± 0.39 μm (n = 50) long, 4.36 ± 0.23 μm (n = 25) wide and 2.61 ± 0.31 μm (n = 25) thick. Elongated pyriform polar capsules (PC) were of equal size (4.44 ± 0.41 μm long and 1.41 ± 0.42 μm in diameter) and each contained a polar filament with 9-10 coils obliquely arranged in relation to the axis of PC. The PC wall was composed of two layers of different electron densities. Histological analysis revealed the close contact of the cyst-like plasmodia with the basal portion of the epithelial gill layer, which exhibited some alterations in the capillary vessels. Based on the morphological and ultrastructural differences, the similarity of the spore features to those of the genus Myxobolus and the specificity of this host to previously described species, we describe a new species named Myxobolus sciades n. sp. in this study.
Acesso aberto (Open Access)
Myxidium volitans sp. nov., a parasite of the gallbladder of the fish, Dactylopterus volitans (Teleostei: Triglidae) from the Brazilian Atlantic coast: morphology and pathology
(2011-08) AZEVEDO, Carlos José Correia de; CASAL, Graça Maria Figueiredo; SÃO CLEMENTE, Sérgio Carmona de; LOPES, Leila Maria Silva; MATOS, Patrícia Santos; ABDEL-BAKI, Abdel Azeem; OLIVEIRA, Elsa; MATOS, Edilson Rodrigues
Myxidium volitans sp. nov. (Myxozoa: Myxidiidae) parasitizing the hypertrophied green-brownish gallbladder of the teleost Dactylopterus volitans, collected in the Atlantic coast near Niterói, Brazil was described based on ultrastructural studies. The spores were fusiform, sometimes slightly crescent-shaped on average 21.7 ± 0.3 µm (mean ± standard deviation) (n = 50) long and 5.6 ± 0.4 µm (n = 30) wide. The spore wall was thin and smooth, comprising two equally-sized valves joined by a hardly visible sutural ridge. Spores containing two pyriform polar capsules (PC) (5.0 ± 0.4 × 2.3 ± 0.3 µm) (n = 30) are situated in each extremity of the spore. The PC wall was composed of hyaline layer (0.20-0.29 µm thick) and by a thin external granular layer. Each PC contains a polar filament (PF) with irregular arrangements that was projected from its apical region to the bases of PC and coiled laterally from bases to the tip of PC. Some regular striations and S-like structures in the periphery of the PFs with four-five irregular sections were observed. Based on the spore morphology, ultrastructural differences and the specificity of the host we describe this parasite as a new myxosporidian, named M. volitans sp. nov.
Acesso aberto (Open Access)
Transfer cells in trichomatous nectary in Adenocalymma magnificum (Bignoniaceae)
(Universidade Federal do Pará, 2016-01) GAMA, Thália do Socorro Serra; DIAS, Ana Cristina Andrade de Aguiar; DEMARCO, Diego
Transfer cells are specialized cells that play an important role where there are high energy costs due to facilitation of transmembrane flow of solutes. This study aimed to investigate the ontogenesis, histochemistry and ultrastructure of glandular trichomes focusing on stalk cells and their possible transfer function. Samples of prophylls of axillary buds, calyces of flowers in anthesis, and flower buds in different stages of development were collected, fixed and processed according to the common methods of microscopy. The glandular trichomes are composed of a secretory head with its cells in columnar format. The stalk is formed by two layers of cells, with the upper layer composed of cuboidal cells where the wall starts to thicken at the beginning of the pre-secretory phase. The secretion is heterogeneous, releasing glucose, other carbohydrates, lipids and phenolic compounds, with two types of release - eccrine and granulocrine. These trichomes are functionally termed as nectaries. The stalk cells appear as transfer cells since they have a thicker anticlinal wall with irregular ingrowths. The presence of transfer cells in thenectaries suggests a high specialization because it improves transport capacity of nectar and compensation in the high energy expenditure for its production and release.
Acesso aberto (Open Access)
Ultraestrutura do espermatozóide de Protothaca pectorina (Lamarck) (Mollusca, Bivalvia) do litoral norte do Brasil
(1997-12) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CASAL, Graça Maria Figueiredo; AZEVEDO, Carlos José Correia de
The ultrastructure of spermatozoa of the Protothaca pectorina (Lamarck, 1818) is described. The most significam differences were found in the structure and arreangement of the acrosomes, with contains two types of material, one fibrilar, the other electrondense granular. It is concluded that sperm ultrastructure is of the primitive type.
Acesso aberto (Open Access)
Ultraestrutura do espermatozóide de Ucides cordatus Linnaeus (Crustacea, Ocypodidae) do litoral norte do Brasil
(2000-09) MATOS, Edilson Rodrigues; MATOS, Patrícia Santos; CORRAL, Laura Felícia Machado; AZEVEDO, Carlos José Correia de
Ultrastructure of spermatozoa of the crab Ucides cordatus Linnaeus, 1763 is described and illustrated. Three parts can be distinguished: 1. the elongate-ovoid acrosome located anteriorly; 2. the cytoplasmic region; and 3. the nuclear region. The acrosome is composed of a thick electron-dense wall and a less electron-dense subacrosomal space. The cytoplasm region connects the acrosome with the nucleus, and three arms filled with microtubules arise from this region. The nucleus is polymorphous. The spermatozoon of Ucides cordatus follows the general pattern described for other Decapods.
Acesso aberto (Open Access)
Ultrastructural description of Ceratomyxa microlepis sp. nov. (Phylum Myxozoa): a parasite infecting the gall bladder of Hemiodus microlepis, a freshwater teleost from the Amazon River
(2013-04) AZEVEDO, Carlos José Correia de; ROCHA, Sonia Maria Rodrigues da; CASAL, Graça Maria Figueiredo; SÃO CLEMENTE, Sérgio Carmona de; MATOS, Patrícia Santos; AL-QURAISHY, Saleh; MATOS, Edilson Rodrigues
A new ceratomyxid parasite was examined for taxonomic identification, upon being found infecting the gall bladder of Hemiodus microlepis (Teleostei: Hemiodontidae), a freshwater teleost collected from the Amazon River, Brazil. Light and transmission electron microscopy revealed elongated crescent-shaped spores constituted by two asymmetrical shell valves united along a straight sutural line, each possessing a lateral projection. The spores body measured 5.2 ± 0.4 µm (n = 25) in length and 35.5 ± 0.9 µm (n = 25) in total thickness. The lateral projections were asymmetric, one measuring 18.1 ± 0.5 µm (n = 25) in thickness and the other measuring 17.5 ± 0.5 µm (n = 25) in thickness. Two equal-sized subspherical polar capsules measuring 2.2 ± 0.3 µm in diameter were located at the same level, each possessing a polar filament with 5-6 coils. The sporoplasm was binucleate. Considering the morphometric data analyzed from the microscopic observations, as well as the host species and its geographical location, this paper describes a new myxosporean species, herein named Ceratomyxa microlepis sp. nov.; therefore representing the first description of a freshwater ceratomyxid from the South American region.