Alarm cells and their distribution in different regions of Barbus sharpeyi's skin

Skin of 20 normal, mature and same size fish (27.27±3.33cm) were subjected to microscopic assessment in different regions including lip, pectoral fin, head, back, side (on lateral line) and abdomen. The skin sections were prepared using routine paraffin embedding and stained by H&E and PAS. The alarm cells distribution were counted in 100ii length of epidermis. Microscopic results showed that voluminous cells existed in the middle to deeper layers of non-keratinization stratified squamous epidermis in all regions except for lip. These cells contained large and euchromatic nucleus in the center of cytoplasm. The cytoplasm has negative reaction to PAS staining. Histo-metrical results showed that shape and number of these cells vary in different regions of skin, with the differences being significant in all regions except for the back, abdomen and pectoral fin skin (P<0.05). Based on the distribution of alarm cells, we could divide the epidermis into four regions: 1- The skin of lip region carrying no alarm cells. 2- The skin of head region with 14.814±0304 alarm cells in 1,0011 length of epidermis. 3- The skin of dorsal and ventral regions and pectoral fin containing 27.628±1.167, 28.228 ±1.54 and 29.629±0.314 alarm cells in 100ti length of epidermis respectively. 4- The skin of lateral region with 47.4971±0.512 alarm cells in 100µ length of epidermis

Ultrastructural study of primordial germ cells, oogonia and oocytes in goat fetus

According to morphological evidences, primordial germ cells (PGCs) are derived from the caudal endoderm of the yolk sac and migrate to embryonic gonads. After entering the gonads, first they differentiate to oogonia and then to oocytes. In the present study, ultrastructure of PGCs, oogonia and oocytes has been examined. Tissue samples were collected from posterior parts of the yolk sacs of fetuses in the early stages of development (with age of less than 1 month), and also gonads of fetuses at later developmental stages (with age of more than 1 month). Samples were studied using transmission electron microscopy after fixation, washing with buffers, dehydration, embedding and staining with uranyl acetate and lead citrate. The Results indicated that PGCs were large with oval to spherical nuclei, reticular chromatin with nucleoli, and there were plenty of glycogen and also different organelles in their cytoplasm. Oogonia showed active mitotic divisions. These cells had regular plasma membranes and were observed as cellular clusters with spherical shape, euchromatin nucleus containing one or more nucleoli, round mitochondria and vacuoles with different sizes in cytoplasm. Oocytes had larger sizes in comparison with oogonia but didn't show cellular clusters