Some notes on the population dynamics of the monogenean gill parasite Gastrocotyle indica

The fish Caranx kalla of different size groups (2 to 18 cm body length) is present during various calender months of the year off the Madras coast (S. India). C. kalla displays a definite progressive shift in growth during successive months; the fish grows from 2 cm (September) to about 18 cm (August) over a period of 12 months. The highest (47%) or lowest (11%) incidence of a monogenean gill parasite Gastrocotyle indica has been observed in the C. kalla size groups 2.0 to 3.9 cm or 16.0 to 17.9 cm; however, the maximum specific density of 10.9 parasite/infested fish was observed in the size group 14.0 to 15.9 cm. Small fish (2.0 to 3.9 cm) carry only larvae (58/100 fish); larger hosts (4.0 to 5.9 cm) larvae (45/100 fish) and juveniles (8/100 fish); individuals of the 6.0 to 15.9 cm size group harbour larval, juvenile and adult stages of G. indica. Fishes of more than 16 cm carry only adult parasites. The level of parasitization is higher on the male hosts (30% incidence; 5 parasites/infested male) than on the females (25% incidence; 4 parasites/infested female). The highest incidences of larval, juvenile and adult G. indica occur in September, February, and May, respectively; the parasite seems to live for 1 year. The host requires a period of about 8 months to acquire immunity against infestation by G. indica or copepod parasites

Hydroxyproline excretion and collagen catabolism in rats of different age groups

Hydroxyproline as an index of collagen catabolism was studied in 432 urine samples collected from rats of different age groups at 4-hr intervals during the 24-hr period. The results showed statistically significant circadian rhythm in urinary hydroxyproline excretion with a peak between 2200 and 0200. The amount excreted is significantly more during the dark hours which can be correlated with the activity cycle. Total amount of excreted hydroxyproline decreases with age. The present results clearly show the importance of the determination of urinary hydroxyproline over a 24-hr period for clinical purposes

Nucleotides and organophosphates of cardiac, fast, and slow muscles of chick during development

Nucleotides like ATP, ADP, AMP and organophosphate, a compd. like creatine phosphate, creatine, and creatinine were estd. in the cardiac, slow anterior latissimus dorsi (ALD) and fast posterior latissimus dorsi (PLD) muscles of the prenatal chick. A decrease in the ATP level and an increase in the ADP​/ATP ratio was obsd. with the advance in development in all muscle types. The increase in ADP level with an increase in development was noted with a complementary increase in the activity of ATP creatine transphosphorylase in all types. A gradual increase in creatine phosphate and a decrease in free phosphate in all the muscle types was recorded. The utilization of ATP as indicated by phosphate potential was suggested to be existing during development by way of increased transphosphorylation. The heart and ALD muscles exhibited similar trends in ATP utilization up to the 16th day. The Ca2+ and Mg2+ activated myofibrillar activity exhibited a decrease with ref. to development. The studies on ocular shortening of glycerinated fibers revealed that the contractility of the fibers progressively increased with development. The ALD fibers are bound to Ca2+ more than that of PLD and heart. The sensitivity of Ca2+ to the fibers changes with development as the PLD fibers become more sensitive:heart fibers lose their sensitivity; and ALD fibers have a mixed nature with ref. to Ca2+ sensitivity

Age related changes in muscle protein degradation

In vitro autolytic degradation of sarcoplasmic proteins in red, white and cardiac muscles increases with advance in age and with increase in temperature, the rate varying with age. Higher activity is seen in the alkaline range in all age groups. Ca2+ activated proteolytic activity also increases with advance in age. © 1978

Effects of training on the extent of experimental myocardial infarction in aging rats

The effects of exercise on the severity of isoproterenol [7683-​59-​2]​-​induced myocardial infarction were studied in female albino rats of 20, 40, 60, and 80 wk of age. The rats were trained to swim for a specific duration and for a particular period. The occurrence of infarcts were confirmed by histol. methods. Elevations in the serum glutamate-​oxaloacetic transaminase (GOT) [9000-​97-​9] and glutamate-​pyruvate transaminase (GPT) [9000-​86-​6] were max. in the sedentary-​isoproterenols and min. in the exercise controls. These changes in the serum transaminases were assocd. with corresponding depletions in the cardiac GOT and GPT. However, age interfered with the responses exhibited by the young and old rats

Age-related changes in rat muscle collagen

Age-related studies of collagen in slow, fast and cardiac muscle of the rat indicate that different fractions of collagen as well as total collagen content vary with age and type of muscle. The total collagen level increases by 30% in slow, 40% in fast and 50% in cardiac muscle as age advances from 5 to 25 months. Collagen of the muscles of old animals is less susceptible to the collagen-degrading enzyme when compared to the young, and the activity of the enzyme decreases significantly with age. The decrease in the solubility of collagen; the amount of hydroxyproline released at 65°C, and the increase in the resistance of collagen to the degrading enzyme seen with aging, indicates that the stability of collagen increases in these muscles with aging

Acetylcholinesterase activity in the embryonic muscles of chick

Acetylcholinesterase activity in the exts. of fast (posterior latissimus dorsi; PLD)​, slow (anterior latissimus dorsi; ALD)​, and cardiac muscles of embryonic chick was estd. by the titrimetric method. The activity in the fast PLD gradually increased up to 16th day of development and gradually decreased afterwards. In the slow ALD there was an increase in activity up to 16th day, but later on the activity became steady. The heart maintained a steady level from the 8th day onwards. The decay of activity in PLD and maintenance of steady level in ALD after the 16th day and in heart from the 8th day of incubation are discussed with ref. to the establishment of muscle-​nerve interaction