Subrata Kumar De

Cytokeratin localization in toe pads of the anuran amphibian Philautus annandalii (Boulenger, 1906).

We have examined cytokeratin distribution and their nature in toe pads of the Himalayan tree-frog Philautus annandalii. Toe pads are expanded tips of digits and show modifications of their ventral epidermis for adhesion. The toe pad epidermal cells, being organized into 3-4 rows, possess keratin bundles, especially in surface nanostructures that are involved in adhesion. Immunohistochemical localization using a pan-cytokeratin antibody revealed that cytokeratin immunoreactivity is the strongest in the mid- to basal cell rows of the epidermis, which parallels our previous ultrastructural observation of dense keratin bundles present in this part of the epidermis. The remainder of the epidermis (i.e., the superficial cell layer) showed little immunoreactivity. Immunoblot analysis revealed that toe-pads possessed keratins prominently in the molecular mass of 50 kDa. Possible presence of keratin 5 in toe pad epidermis has been correlated with its usual distribution pattern in mammalian epidermis.

Ultrastructural studies on the nuclear elements in differentiating and degenerative ciliated olfactory neuron of Pseudapocryptes lanceolatus (Gobiidae: Oxudercinae)

Abstract The cellular event of neurogenesis and neural degeneration of ciliated sensory receptor neuron within the adult olfactory neuroepithelial system has been studied in Pseudapocryptes lanceolatus (Bloch and Schneider, 1801) under light microscope (LM), fluorescence microscope and transmission electron microscope (TEM: Morgagni 268D) respectively. The unilamellar olfactory apparatuses of P. lanceolatus were dissected and fixed in 2.5% glutaraldehyde and 4% paraformaldehyde in 0.1 M phosphate buffer (pH 7.2–7.4) at 4 °C for microscopical studies. The LM study indicates that the progenitor basal cell proliferates to form electron lucent basal cell which differentiates into ciliated sensory receptor neuron within the olfactory neuroepithelium. Investigation under fluorescence microscope using Acridine Orange revealed that the nuclear elements in differentiating stages of electron lucent basal cell, mature and degenerating sensory receptor cell show notable features of gradual condensation. TEM study indicates the subsequent condensation of chromatin granules (diameter ranging from 10 nm–20 nm to 15 nm–30 nm) in various differentiating stages of electron lucent basal cell. The mature ciliated sensory receptor cell possesses chromatinized nucleus with large accumulation of chromatin granules (diameter: 20 nm–30 nm) at the peripheral nucleoplasm whereas degenerating sensory receptor cell possesses fragmented chromatin fibers. Therefore, these distinctive features of chromatin condensation are assumed to be a prime subcellular indicator of neural aging of olfactory sensory receptor cell.

Vesicular Diversity and Crowding within the Olfactory Sensory Receptor Neuron

The olfactory sensory receptor neuron (OSRN) is an important cellular component of the vertebrate olfactory system that are responsible for detection and discrimination of different type of chemical cues from the external environment [1]. The neural communication between the sensory receptor cells is generally mediated through vesicles [2]. The fine structural details of OSRN aim to unfold the vesicular morphometry, trafficking and crowding in relation to olfactory signal transduction in a mudskipper [Pseudapocryptes lanceolatus] of South East Asia.

Age-related Cytological Changes of Fibroblast Cell and Fila Olfactoria in Fish: [Pseudapocryptes lanceolatus (Bloch and Schneider)]

The fibroblast cell is an important cellular component of olfactory lamina propria of Pseudapocryptes lanceolatus (Bloch and Schneider) which plays a significant role to constitute the fila olfactoria [1]. The present study is emphasized on the fine structural details on fibroblast cell to unfold the subcellular basis of age-related consequences of the fila olfactoria in olfactory neuroepithelial system in fish [P. lanceolatus].

Electron microscope based X-ray microanalysis on bioaccumulation of heavy metals and neural degeneration in mudskipper [Pseudapocryptes lanceolatus]

The bioaccumulation of heavy metals and its probable cytological consequences in ciliated olfactory sensory receptor neuron (OSN) of two different groups of Pseudapocryptes lanceolatus has been studied using X-ray microanalysis in transmission electron microscopy (TEM-EDX) [i.e., Group I, collected near Kanchrapara (22.56°N 88.26°E) and Group II, collected near Tribeni (22.99°N 88.40°E) of West Bengal, India]. The ciliated OSN is a bipolar neuron and possesses a prolonged dendron with four to six cilia at the olfactory knob, perikaryon, and axon. Excess accumulation of copper (94.50%) and iron (83.81%) was noted under TEM-EDX in the cytoplasm of the olfactory knob as well as nucleoplasm of ciliated OSNs in P. lanceolatus (Group II). The degenerating ciliated OSNs show distinct features of lysis of the plasma membrane at the olfactory knob, disintegration of cytoskeletal structures in perinuclear cytoplasm and axoplasm, and fragmented chromatin fibers with granules (diameter, 20–30 nm) in the nucleoplasm. Crowding of acetylcholinesterase-positive vesicles (diameter:, 30–40 nm) at the terminal part of the axoplasm was related to accumulation of heavy metals in degenerating ciliated OSNs of P. lanceolatus (Group II). The recorded concentrations of heavy metals in the same organ among different groups of P. lanceolatus in varying geographical areas indicates the stress of concerned environmental health. This ultrastructural interpretation on the fish ciliated OSN is a prerequisite for monitoring environmental health as well as metallobiology of several neurodegenerative disorders in fish caused by bioaccumulation of heavy metals.

Thymic Secretory Cells In A Gobiid Fish

C. Ultrathin sections were doublestained with uranyl acetate and lead citrate. These were viewed in transmission electron microscopeoperated at 60 kV.The shape and size of thymic granulated secretory cells are not constant. The nucleus is polarizedwith one or two nucleoli. Sometimes the nucleolus lies close to the nuclear membrane. The euchromatinand heterochromatins are uniformly distributed in the nuclearplasm. Both rough and smooth endoplasmicreticulum are moderate in the cytoplasm. The centrioles are prominent in some of these cells. TheGolgi complex with vesicles and vacuoles is also noted. Some of the vesicles possess hairy doublemembranes. Various mitochondia with fully formed cristae are also observed . Lysosome like organellesand multivesicular bodies (MVBs) are few in number. Both electron dense and electron lucent granulesappear in different sizes in these cells.Thymus acts as a lymphomyeloid organ in fishes. An important class of secretory cells is found inthe thymus of