|Ghulam Nabi Hajjam (firstname.lastname@example.org)|
|Zoology, University of Kashmir, Hazratbal Srinagar, J&K|
|Dr. G.N. Hajjam joined Higher Education Department as Adhoc lecturer at Govt. Degree College Boys Anantnag and worked there from 1999-2000. After clearing Public Service Commision he joined Government Degree College for Womens Anantnag as regular member in 2001. Presently he is working as Head Department of Zoology, Government Degree College Tral. Moreover he is consultant Zoologist with The Himalayan Ecological and Conservation Research Foundation J&K. He has to his credit some research papers in National and International Journals|
|The present investigations deal with the ultrastructural, histochemical and biochemical aspects of the urinogenital system of the freshwater teleost of Kashmir, Schizothorax niger Heckel.
The surface morphology of the kidney reveals that it is composed of cranial and caudal portions with a variable number of haemopoietic tissue, glomeruli and collecting tubules. The ureter is lined with stratified epithelial cells. The testis shows numerous tubular lobules which arise ventrally from vasa defferentia and send out trabeculae into its lumen. The wall of the vasa defferentia is supported by smooth muscles to provide support to the hanging lobules. The mature ovary shows presence of oocytes of various stages of development whereas at the spent stage, only follicular mass is observed. The mature eggs are roughly spherical to oval in shape having polar bodies attached to its surface. The egg membrane is dominated with inconsistent mounds. The micropylar pit is somewhat depressed and cup shaped. The oviduct is lined with stratified epithelium.
Transmission electron microscopy of the kidney distinctly reveals that glomerulus is composed of epithelial cells, endothelial cells and mesengial cells. The prominent features of the epithelial cells of the first proximal tubule are the well developed nuclei, secondary lysosomes and microvilli forming brush border. The epithelial cells of the second proximal tubule show greater abundance of mitochondria. The cells of the melanomacrophage of the haemopoietic tissue in the epithelial cells are irregular in shape having lysosomal granules. Unlike females, the epithelial cells in the males exhibit wandering cells, rough endoplasmic reticulum and many dense secretory granules. The epithelial cells of the distal tubules are comparatively narrower in diameter and bear clusters of cilia and junctional complex adjacent to tubular lumen. The collecting tubule shows occasional microvilli, cilia, mucous granules, and endoplasmic reticulum. The ureter exhibits the presence of finger print like structures to expand the superficial area for storage of urine.
TEM studies of spermatozoon of testis reveal that the spermatozoon head is spherical with a membrane bounded acrosomal vesicle at its anterior end. The middle piece of the spermatozoon is observed to contain two spherical mitochondria on its membrane, while the tail flagellum shows abundance of microtubules of classical “9+2” pattern. The interstitial cells are noted to be polygonal in shape with numerous mitochondria having tubular cristae. The sertoli cells, on the other hand contain roughly shoe shaped nuclei with numerous lipid droplets. The epithelial cells of the vasa defferentia possess irregular nuclei with lipid droplets and secretory granules.
The thecal cells of the ovulatory follicle possess an extensive agranular endoplasmic reticulum and large mitochondria. The granulosa cell depicts an irregular nucleus of high electron density. The cytoplasm possesses a number of cortical alveoli and lipid droplets. Chorion of the follicle shows three distinct layers, an outer layer, homogenous intermediate layer and the the multilamellar layer. In the vicinity of granulosa cell is observed large triangular micropylar cell. The epithelial cell of the oviduct is beset with tonofilaments and other cellular organelles thereby, suggesting its secretory nature for transporting the eggs to exterior during spawning
Proteins are demonstrated in the kidney, ureter, testis, vasa defferentia, ovary and oviduct. The glomeruli, first and second proximal tubules, collecting tubules, the stratified epithelial cells of the ureter, the interstitial cells, sertoli cells, wall of spermatogonia, primary and secondary spermatocytes, the stratified squamous epithelial cells and tunica adventitia of vasa defferentia, the granulosa cells, zona radiata, yolk granules and the stratified epithelial cells of the oviduct, exhibit well pronounced reaction for proteins.
Intense reaction for neutral mucin is observed in the mesengial cells of the glomerulus and brush border of the collecting tubules, the mucous secreting goblet cells of the ureter, the luminal region of the seminiferous tubules, the mucous cells of the vasa defferentia, zona radiata externa and cortical alveoli of secondary oocytes and the secretory cells of the oviduct. No reaction is observed in the blood vessels, the connective tissue, the primary oocytes and the zona radiata interna of the secondary oocytes and the muscularis.
Except ureter, vasa defferentia and the oviduct, rest of the tissues studied show presence for acid mucin. The sites of intense localization include, the collecting tubules, the interstitial cells, sertoli cells, and peripherally situated different stages of spermatocytes, the granulosa cells, zona radiata and peripheral cortical alveoli.
Uniformly intense reaction for neutral lipids are found to be distributed in the renal tubules, glomeruli, collecting tubules, blood vessels, the interstitial cells, sertoli cells, tunica albuginea, the yolk granules and the granulosa cells. However, the ureter, vasa defferentia and the oviduct are observed to be totally devoid of lipids.
Biochemical investigations distinctly reveal that proteins are the major constituents of the urinogenital organs of the fish studied, followed by lipids and carbohydrates. The highest concentration of proteins is noted to be present in the kidneys (30.50±2.55) at the beginning of spawning phase, whereas the lowest value of protein content (4.0±0.63) is observed in the late resting stage and gradually increases during growth phase as well as in maturation phase. In the testes, maximum protein content (30.30±2.54) is observed during spawning phase and lowest concentration (3.70±0.52) in the late resting stage. The concentration of proteins in the ovaries of fish investigated is found to be highest (29.5±1.44) during growth phase and lowest (3.20±0.32) in the late spawning phase.
The kidneys show highest lipid content (18.30±0.87) in the mid maturation phase and lowest (4.10±0.76) in the late spawning phase. In testes, the higher lipid content (18.10±0.86) is noted to be in mid maturation phase and lowest (3.00±0.75) during the late spawning phase. Ovaries show higher concentration of lipids (19.0±1.12) in the mid growth phase and lowest content (4.80±0.52) in the late spawning phase.
Carbohydrates are observed to be present in minor concentration in the urinogenital organs as compared to proteins and lipids. The results of the present investigation show that the kidneys possess higher concentration of carbohydrates (0.99±0.80) in the late growth phase and lowest (0.34±0.05) during the late spawning phase. The testes depict higher concentration of carbohydrates (0.98±0.08) in the late growth phase and lowest (0.36±0.06) in the late spawning phase. The ovaries reveal higher concentration of carbohydrates (0.99±0.80) in the late growth phase and lowest (0.33±0.05) in the late spawning phase. It has been observed that there is a positive correlation within the protein content (0.77 - 0.82), lipid content (0.73 - 0.98) and carbohydrate content (0. 74 – 0.81) of the kidneys, testes and ovaries of the fish studied.
It may be concluded from the present investigation that the ultrastructural analysis provides an insight into the surface architecture and subcellular details of the different organs of the urinogenital system of Schizothorax niger which are not only of vital utility in interpreting their structural organization, but also relate them to their physiological activities. Besides, such type of studies furnishes a platform for future studies in relation to phylogeny, pathology, pollution and stress conditions in aquaculture.
Histochemical localization of proteins, mucopolysaccharides (neutral and acidic) and neutral lipids from their natural locations in the histological sections of the kidneys, testis, ovary and their associated ducts provide not only their cellular architecture with respect to their structural and functional significances but also help us in understanding the functional characterization of cellular components. Moreover, these investigations are of great help in understanding the various physiological and pathological processes. On the other hand, fluctuations in biochemical estimation of proteins, lipids and carbohydrates in various seasons is suggestive of the fact that the energy demands of the fish investigated varies throughout the year.