Browsing by Author "S. Mittal"

Now showing 1 - 7 of 7

Characterisation of glycoproteins in the secretory cells in the operculum of an Indian hill stream fish Garra lamta (Hamilton) (Cyprinidae, cyprinidae, cypriniformes)
(2002) S. Mittal; Pinky Mittal; A.K. Mittal
Glycoproteins (GPs) elaborated by the secretory cells in the opercular epidermis (OE) and the epithelium lining the inner surface of the operculum (EISO), of an Indian hill stream fish Garra lamta have been analysed by means of a battery of histochemical methods. These included methods for the characterisation and simultaneous visualisation of GPs with oxidizable vicinal diols, O-acyl sugars, O-sulphate esters and sialic acid residues without O-acyl substitution or with O-acyl substitution at C7, C8 or C9. Results obtained in this study show that conventional periodic acid Schiff's and alcian blue based procedures are less sensitive and largely fail to identify different classes of GPs. In the OE the secretory cells involved in the synthesis of GPs are the epithelial cells, the mucous cells and the club cells. Based on the histochemical characterisation of GPs, the mucous cells are distinguished in to two types, Type A and Type B. The majority being of Type A. In the EISO, in contrast, the club cells are absent and most mucous cells belong to a third category, Type C. Type A and Type B mucous cells are few. GP classes synthesised by the secretory cells and released on the outer surface of the operculum, directly exposed to the environmental hazards show significant differences in their composition and concentration from those on, the relatively well protected, inner surface of the operculum. These are discussed in relation to the physiological significance of the GP classes with special reference to their role in lubrication, protection and inhibition of the invasion and proliferation of pathogenic micro-organisms.
Glycoproteins in the Buccal Epithelium of a Carp, Cirrhinus mrigala (Pisces, Cyprinidae): A Histochemical Profile
(2014) M. Yashpal; U. Kumari; S. Mittal; A.K. Mittal
Glycoproteins (GPs) were visualized histochemically in the secretory cells - the mucous goblet cells (the type A and the type B), the rodlet cells and the epithelial cells in different regions of the buccal cavity of Cirrhinus mrigala. The type A mucous goblet cells, the type B mucous goblet cells, the rodlet cells and the epithelial cells elaborate GPs with oxidizable vicinal diols and GPs with sialic acid residue without O-acyl substitution. The type A mucous goblet cells, in addition, contain moderate amounts of GPs with O-sulphate esters. The type B mucous goblet cells, in contrast, contain high concentrations of GPs with O-sulphate esters. The rodlet cells secrete small amounts of GPs with oxidizable vicinal diols. The analysis of the results elucidates interesting differences in the composition and concentration of GPs in the mucus elaborated by the secretory cells indicating the potential importance of the glycoproteins in the buccal cavity. These GPs could be considered to represent a mechanism for modulation of the composition of the protective mucus layer correlated to specific functions. © 2013 Blackwell Verlag GmbH.
Glycoproteins in the epithelium of lips and associated structures of a hill stream fish harra lamta (Cyprinidae, Cypriniformes): A histochemical investigation
(2008) Pinky; S. Mittal; A.K. Mittal
A series of histochemical procedures were employed to localize and characterize glycoprotein (GP) classes elaborated in the epithelia of the upper and lower lips and associated structures, namely the rostral cap, the adhesive pad, the horny upper and lower jaw sheaths and the folds of skin between them, of a hill stream fish Garra lamta. The epithelia of the lips, the folds of skin and the major portions of the rostral cap and the adhesive pad are mucogenic. The epithelia of the horny jaw sheaths and parts of the rostral cap and the adhesive pad are keratinized. Based on the histochemical characterization of GPs, the cells involved in the secretions in the epithelia at the mucogenic regions of the rostral cap and the adhesive pad comprise the epithelial cells, the type A mucous cells and the club cells. In the lips and the folds of skin, in contrast, the club cells are absent and most mucous cells belong to the type B category. Type A mucous cells are few. GPs elaborated by cellular components of the mucogenic epithelia include GPs with oxidizable vicinal diols, GPs with O-sulphate esters, GPs with sialic acid residues without O-acyl substitution or with O-acyl substitution at C7, C8 or C9 and GPs with O-acyl sugars. The different types of cells show significant differences in the classes as well as in the concentrations of the GPs elaborated by them. GPs have also been identified in the subcorneal space between the unculi and the epithelial cells in the replacement layer in the epithelia at the keratinized regions. Elaboration of more than one type of GPs suggests a basis for functional discrimination in their role in the mucous secretions at the surface as an adaptation to the feeding ecology and the environment inhabited by the fish. © 2008 Blackwell Verlag.
Histochemical analysis of glycoproteins in the secretory cells in the epidermis of the head skin of Indian Major Carp, Labeo rohita
(Elsevier Ltd, 2012) A.K. Rai; N. Srivastava; U. Kumari; S. Mittal; A.K. Mittal
A series of histochemical procedures were employed to localise and characterise glycoprotein (GP) classes produced by the epithelial cells, the type A and the type B mucous goblet cells (MGCs) and the club cells in the epidermis of Labeo rohita. The epithelial cells secreted GPs with oxidizable vicinal diols and GPs with sialic acid residues without O-acyl substitution in low concentrations. The type A MGCs and the type B MGCs, in contrast, produced these GPs in high concentrations. Further, these MGCs produced GPs with O-sulphate esters as well. GPs with O-sulphate esters were produced in high concentration by the type A MGCs and in low concentration by the type B MGCs. The club cells produced GPs with oxidizable vicinal diols in trace amounts. Production of more than one type of GPs suggested a basis for functional discrimination in their role in the mucous secretions at the skin surface. This is considered an adaptation to environment inhabited by the fish and is discussed in relation to their role in lubrication, protection and inhibition of the invasion and proliferation of pathogenic micro-organisms. © 2012 Elsevier Ltd.
Occurrence of keratinization in the structures associated with lips of a hill stream fish Garra lamta (Hamilton) (Cyprinidae, Cypriniformes)
(Blackwell Publishing Ltd, 2004) Pinky; S. Mittal; M. Yashpal; J. Ojha; A.K. Mittal
Keratinized regions were found to occur in the rostral cap, adhesive pad and horny jaw sheaths associated with the lips of Garra lamta, which inhabits fast flowing turbulent hill streams. In these structures, the surface epithelial cells were modified into characteristic keratinized spine-like or columnar tooth-like unculi, which would provide firm anchorage for the fish on the substratum and assist the fish in browsing or scraping food materials from it. © 2004 The Fisheries Society of the British Isles.
Response of the chromatophores in relation to the healing of skin wounds in an Indian Major Carp, Labeo rohita (Hamilton)
(Elsevier Ltd, 2012) A.K. Rai; N. Srivastava; A.K. Nigam; U. Kumari; S. Mittal; A.K. Mittal
Chromatophores show significant changes during healing of skin wounds in Labeo rohita (Common Name - Rohu). Wound area can be divided into regions I, II and III. After infliction of wound, skin colour becomes significantly dark by 2. h that is gradually restored by 2. d. In regions II and III at 5. min, epidermal melanophores appear with beaded dendrites. In these regions at 2. h and in region I at 6. h, epidermal melanophores appear small, rounded or irregular shaped having dendritic processes with aggregated melanosomes. Subsequently, melanophores appear having elongated dendrites with dispersed or aggregated melanosomes. At 24. h, clusters of pigmented bodies appear in regions I and II. These bodies increase up to 2. d, and then diminish gradually and disappear by 8. d. Changes in dermal melanophores in region II at 5. min indicate the onset of degeneration. Degenerating melanophores increase up to 12. h, then gradually decline, and disappear by 4. d. Simultaneously, stellate melanophore reappear, gradually increase and appear like control by 8. d. Dermal melanophores in region III at different intervals appear stellate. In region I stellate dermal melanophores appear at 4. d. Stellate melanophores in all regions show different distribution of dispersed or aggregated melanosomes. With the appearance of dermal melanophores, highly refractive, crystalline structures, possibly the refractive platelets of the iridophores, are visualized around them. At subsequent intervals, these are frequently observed. This study provides interesting insights in injury induced changes in chromatophores in fish. The findings could be considered useful in perception of intriguing features in the development of pigment research in future. © 2012 Elsevier Ltd.
Surface ultrastructure of gill arches and gill rakers in relation to feeding of an Indian major carp, Cirrhinus mrigala
(Elsevier Ltd, 2009) U. Kumari; M. Yashpal; S. Mittal; A.K. Mittal
The surface ultrastructure of the gill arches and the gill rakers of an herbivorous fish, Cirrhinus mrigala was investigated by scanning electron microscopy. These structures show significant adaptive modifications associated with the food and feeding ecology of the fish. Closely lying short gill rakers and narrow inter-raker channels on the gill arches are associated to filter and retain food particles. Prominent epithelial protuberances on the gill rakers and the gill arches enable the taste buds, located at their summit, to project well above the surface of the epithelium. This could increase the efficiency of the taste buds in selective sorting of palatable food. Surface specializations of the postlingual organ are recognized adaptive modifications for selecting, trapping or holding food particles. Prominent molariform teeth born on the lower pharyngeal jaw, and the chewing pad opposite it, are associated to work together as an efficient pharyngeal mill. Mucous goblet cells are considered to elaborate mucus secretions to trap, glue and lubricate food particles for their smooth transport for swallowing. © 2009 Elsevier Ltd. All rights reserved.