Functional and developmental morphology最新文献

Specimens of Eremina ehrenbergi Roth, 1839, were collected in the El-Omayed area of the Sahara Desert, west of Alexandria. This simultaneously hermaphrodite snail has a comparatively small gonad enclosed in a thin membrane. The gonad is composed of a mass of branched tubules, each differentiated to a generative proximal half and a conducting distal half. The primitive germ cells proliferate from germinal cells forming a discontinuous layer in the germinal wall of each tubule; they undergo spermatogenesis or oogenesis at the original site of their proliferation. A cluster of spermatogonia may be derived from one primitive germ cell and it develops round a "Sertoli" cell. The division and differentiation of the cells in each cluster are strictly synchronized. The role of the gonad in formation of the spermatophore is restricted to the production of clusters of mature spermatozoa, which are discharged, without the "Sertoli" cell, via three efferent ductuli connecting the conducting portions of the gonadal tubules with the hermaphrodite duct. The sperm has the same appearance as in vertebrates and can be studied in smears prepared from the gonad or the middle of the hermaphrodite duct, where they are collected and stored for a time.

Freeze-fracture replicas of the plasma membrane and tight junctions (Tj) of intestinal epithelial cells were studied in Tilapia nilotica fish exposed to the pyrethroid insecticide, neopybuthrin. Exposing fishes to different repeated concentrations of 1/2 LC50 of neopybuthrin caused a significant decrease in the population density of IMPs in P- and E-faces. Tight junctions were also affected by neopybuthrin treatment. They appeared fragmented and discontinued, and their strands were fewer in number as compared with controls. Since the structure and number of Tj are major determinants of epithelial permeability, it is postulated that neopybuthrin treatment may affect the intestinal permeability of T. nilotica.

Ultrastructural differences between cardiac and striated muscle fibres observed in the ocellated skink (Chalcides ocellatus ocellatus) indicate that functional differences have a structural correlate in the muscle cells. Although the myofibrils of both the cardiac and skeletal muscles displayed the same typical band pattern, differences in mean nuclear diameter and sarcomere length and in the A, I, Z, H, and M bands (discs) were observed. In addition, differences were found in the number, size and distribution of the mitochondria in the two types of muscle fibres. The Golgi complex was indistinguishable in skeletal muscles, but small Golgi vesicles could (with difficulty) be identified in cardiac muscle fibres. Skeletal striated muscle fibres were also found to contain significantly more glycogen granules, smooth sarcoplasm vesicles and heterochromatin than cardiac muscles. Three types of junctional complexes were identified in the cardiac muscles.

The effect of the anticancer drug adriamycin on the morphology of the erythrocytes as well as some blood parameters were studied in the Egyptian toad Bufo regularis. Injecting the toads subcutaneously in the dorsal lymph sac with adriamycin at a dose level of 2 mg/kg body weight once every three weeks for 12 weeks induced the formation of abnormalities in the cytoplasm and nuclei of the erythrocytes. Its administration also caused severe anaemia, since the number of red blood corpuscles, haemoglobin content and haematocrit values were obviously decreased throughout the whole experimental period. The total leucocytic count was also diminished. On the other hand, the erythrocyte sedimentation rate was increased all over the experiment.

The effects of vitamin A (retinolum palmiticum) administered to pregnant mice on the cell-mediated immunity of the offspring were studied in random-bred ICR mice. Delayed-type hypersensitivity (DTH) to sheep red blood cells was assayed after immunization of the control and experimental young in the 4th postnatal week. The administration of vitamin A, in doses of 5,000 IU, on days 15-17 of pregnancy depressed DTH of the female offspring. On the other hand, the administration of single doses of 5,000 and 10,000 IU on the 16th day of pregnancy increased DTH in the offspring. The effects were correlated to the sex and body weight of the offspring, the highest DTH being observed in the female offspring with a low body weight.

The presence of organum vasculosum hypothalami in the 3rd cerebral ventricle in goat has been confirmed. The surface of this organ is undulated, covered with cylindrical or cuboidal ependyma. Its rostral pole has simple, finger-shaped protrusions, the number of which increases during the "inactive" period (females: anestrus, males: out of season; both sexes: April), sporadically they occur in the mating season (females and males: October, November). Except for cilia and microvilli, no other supraependymal structures have been found. The organum vasculosum hypothalami of goats does not have dense capillary network and neither has "nucleus organi vasculosi hypothalami" been found.

The Golgi apparatus and alkaline and acid phosphatase and nonspecific esterase activities were studied in the jejunal epithelium of adult male albino mice (Mus musculus) under normal conditions and after MTX treatment. In the control, the Golgi apparatus took the form of rods, spheres and crescents occupying the supranuclear region. After MTX, the Golgi apparatus, in most of the cells, was hypertrophied. In the control cells, alkaline and acid phosphatase and nonspecific esterase activities were moderate and localized supranuclearly, but were intense in the brush border and basement membrane. After MTX, all three enzyme activities increased, with a marked reaction in the brush border and basement membrane. The increase in alkaline phosphatase may mean that more phosphate transport is needed in the active phosphorylation process or in the transfer of MTX macromolecules across the cell membrane, or it may be due to MTX-induced disorganization of metabolism. The increase in acid phosphatase activity denotes an increase in catabolic processes resulting from imbalance of lysosomal function, while the rise in nonspecific esterase activity could be related to fatty acid metabolism, or it might be due to the detoxicant function of esterases. In all control and MTX-treated specimens, the supranuclear concentration of these enzymes coincided with the localization of the Golgi apparatus.

The paper describes Wallagotrema indicus n.sp., a freshwater monogenean recovered from the gill filaments of the freshwater sheat-fish Wallago attu Bloch and Schn. It is characterized by the number of head organs, an accessory piece on the cirrus, wings on the anchors and a beak-like outgrowth on the dorsal anchors, together with numerous other differences in the shape and size of various body parts. On the basis of these findings, the generic diagnosis of Wallagotrema is amended and a key to the various species of this genus is appended.

The histological and histochemical state of the thyroid gland of Oreochromis mossambicus was analyzed after 20 days' exposure of the fish to BHC (p less than 0.001 ppm). Histological changes after exposure included acolloidal and atrophied follicles and goitre formation. Follicular and nuclear diameter and the E/T ratio were significantly (p less than 0.001) higher than in the corresponding controls. The above insecticide led to thyroid dysfunction. The histochemical characteristics of the gland also changed after BHC treatment. When exposed fish were transferred to normal, clear, dechlorinated water, the altered follicles displayed remarkable recovery of activity and thyroid function returned to almost the same state as in normal controls. Histological and histochemical evaluation at 10-day intervals revealed healthy functional restitution of the gland, indicating that BHC-induced changes are reversible.