Now showing items 1-6 of 6

    • Article

      Effect of different diets on the ultrastructure of hepatocytes of Chanos chanos fry (Chanidae: Teleostei): An electron microscopic and morphometric analysis 

      V Storch, W Stählin & JV Juario - Marine Biology, 1983 - Springer-Verlag
      The hepatocytes of milkfish fry offered different artificial diets (carbohydrate-, lipid-, protein-oriented) and live food (Artemia spp., Brachionus plicatilis) differ considerably both qualitatively and quantitatively as was shown by means of transmission electron microscopy and planimeter. Food deprivation, too, resulted in ultrastructural alterations of milkfish fry hepatocytes. Thus, this cell type might be used as an indicator of quality and quantity of food in teleosts.
    • Article

      The effect of starvation and subsequent feeding on the hepatocytes of Chanos chanos (Forsskal) fingerlings and fry 

      V Storch & JV Juario - Journal of Fish Biology, 1983 - Academic Press
      Excised liver sections of the milkfish, Chanos chanos, fry and fingerlings were studied by transmission electron microscopy. The hepatocytes underwent marked ultrastructural alterations in response to food deprivation of 10-day starvation for fry and 2 months for the fingerlings. The prominent features characterizing the hepatocytes of starved fish were: a reduction of cell and nucleus size; apparent loss of nucleoli; condensation of chromatin material in fry; loss of stored glycogen; reduction of ER profiles; increase in the number of electron-dense bodies containing large amounts of iron in fingerlings; and an increase in mitochondrial size. These changes were reversible following short periods of re-feeding, i.e. 2 days for fry and 4 days for fingerlings, using natural food for the fry and formulated diet for the fingerlings.
    • Article

      Gill structure, anatomy and habitat of Anodontia edentula: Evidence of endosymbiosis 

      MJHL Lebata & JH Primavera - Journal of Shellfish Research, 2001 - National Shellfisheries Association
      Surveys and interviews were conducted to determine sources and habitat of Anodontia edentula. Results showed that they inhabit muddy substrate of mangrove areas or the adjacent mudflats, burying at 20-60 cm deep in the mud. They are strategically situated in the sulfide-rich, low-oxygen layer of the substrate but have access to oxygen through their inhalant tube; both sulfide and oxygen are essential for their survival. Study of the clam s gross anatomy revealed thick, fleshy, deep purple to blackish brown gills; reduced digestive structure; and a highly elastic foot capable of extending several times longer than its body length. These observations conform with the anatomy of fellow lucinid clams. Furthermore, scanning electron micrographs showed coccoid or spherical bacteria occupying bacteriocytes in the clam s gills. Intermediate cells separating bacteriocytes observed in other lucinids were also noted in the SEM.
    • Conference poster

      Hepatopancreas cells as monitor cells for the nutritional value of prawn diets in aquaculture 

      G Vogt, FP Pascual & ET Quinitio - In Y Taki, J Primavera & JA Llobrera (Eds.), Proceedings of the First International Conference on the Culture of Penaeid Prawns/Shrimps, 4-7 December 1984, Iloilo City, Philippines, 1985 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The hepatopancreas is considered to be the central organ of metabolism in decapod Crustacea. It is a system of blind tubules consisting of four cell types. The E-cells at the summits of the tubules develop into R-cells (for resorption of nutrients), F-cells (for production of digestive enzymes) and B-cells (function unknown).

      The ultrastructure of Penaeus monodon R-cells changes largely after starvation and feeding different diets. B-cells show slight reactions, while F- and E-cells are rather constant. Thirteen day-starvation results in a large decrease of the cell size and in a significant reduction of all cell organelles. After seven days starvation and four days refeeding with various extreme diets, the R-cells develop completely different food-specific ultrastructures. A distinct proliferation of the endoplasmic reticulum is characteristic of protein diets. Large fat drops are the main feature after refeeding with cod liver oil. Sucrose feeding results in "empty" cells with only few organelles. The most diversified ultrastructure with fat droplets and a high amount of all cell organelles is obtained by feeding a mixed diet.

      The study indicates that R-cells are very sensitive to the application of different diets. They could be used as monitor cells for the nutritional value and the availability of a diet for prawns. Particularly poor or badly formulated feed could be detected early by electron microscopy. This method may be very helpful for the development of artificial prawn diets in aquaculture, especially if natural sources will be used as food components.
    • Article

      Influence of nutrition on the hepatocytes of Chanos chanos (Chanidae: Teleostei) 

      V Storch, H Segner, JV Juario & MN Duray - Zoologischer Anzeiger, 1984 - Elsevier
      The hepatocytes of milkfish (C. chanos) fry and fingerlings offered a variety of diets differ considerably as was shown by means of transmission electron microscopy. For fry it was shown that a 7 day starvation period results in a heavily altered hepatocyte ultrastructure but that even in this stadium fast regeneration was possible. Chlorella turned out to be the worst diet, among the artificial diets, the trout diet provoked the best regeneration. In fingerlings a prolonged starvation period was necessary to affect hepatocytes. In some cases considerable indications of liver cell degeneration were found after feeding certain diets for 2-3 months. Even dried lumut and lab-lab did not create optimal hepatocyte ultrastructure. Feeding with cod liver oil did not result in deposition of lipid droplets in the hepatocytes of fingerlings, what is in contrast to milkfish fry hepatocytes.
    • Article

      An ultrastructural study on the occurrence of aberrant spermatids in the testis of the river sculpin, Cottus hangiongensis 

      GF Quinitio & H Takahashi - Japanese Journal of Ichthyology, 1992 - The Ichthyological Society of Japan
      The process of spermatogenesis and spermiogenesis in the river sculpin,Cottus hangiongensis, was observed ultrastructurally. During spermatogenesis, some germinal cysts in the seminal lobules were found to contain spermatocytes, which were provided with irregularly shaped nuclei, doughnut-shaped mitochondria, and atypical intercellular bridges with multiple disk-like cisternae. In addition, many cysts containing binuclear spermatids were observed in the testis. Within the condensed chromatin of the paired nuclei of the aberrant spermatids, highly electron-dense granules occurred, becoming the core of successively developing chromatin globules. The chromatin globules increased in size, resulting in an enlargement of the paired nuclei. These cells were finally released from the cyst into the lumen of the seminal lobules and underwent further degeneration, thus appearing as characteristic ‘spermatid masses’ in the mature testes.