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Hepatopancreatic unsaturated fatty acids during aestivation of the snail, Pila globosa
Comp. Biochem. Physiol., 1968, Vol. 24, pp. 279 to 282. Pergamon Press. Printed in Great Britain
SHORT COMMUNICATION HEPATOPANCREATIC UNSATURATED FATTY ACIDS DURING AESTIVATION OF THE SNAIL, P I L A GLOBOSA R. V. K R I S H N A M O O R T H Y Department of Zoology, Sri Venkateswara University, Tirupati, A.P., India
(Received 20 ffune 1967) Abstract--1. Changes in the levels of ascorbic acid, iodine number and percentage fat in the hepatopancreas of Pila globosa, during aestivation were studied. 2. Iodine number of fat and ascorbic acid content were increased in aestivated snails. The percentage fat decreased. 3. It was suggested that the increase in the iodine number of fats might be due to the increased levels of antioxidants like ascorbic acid. INTRODUCTION P~CISE and adequate information about the physiological aspects of aestivation in snails is as yet scantily available. The aestivating snails show reduced oxygen eonsumption (Meenakshi, 1957), reduced flavin metabolism (Anjani Prasad & Krishnamoorthy, 1962) and considerable reduction in succinie dehydrogenase activity (Ekstein & Abraham, 1959). Reduction in the activities of enzymes concerned in carbohydrate metabolism (Raghupathirami Reddy, 1965) has also been reported during aestivation. The sources of energy and causal mechanisms of aestivation are poorly known. Some evidence is available concerning the utilization of accumulated fats (George & Desai, 1954) during aestivation of Pila globosa. In this note the degree of unsaturation of fats during aestivation of P. globosa, which is known to naturally aestivate when ponds dry up, is reported. MATERIAL AND METHODS Pila globosa were collected from the ponds around Tirupati and stocked in laboratory aquaria. One batch of animals was kept in an aquarium at 28°C and the animals of another batch were buried in dry sand in a glass trough and placed in a thermostatically controlled chamber at 35°C in order to aestivate them. After 2 months both active and aestivated animals were sacrified for the estimations. Hepatopancreatic tissue was used. The whole organ was carefully dissected, freed from the gonads and weighed in a Sartorius balance. In some of the experiments, the hepatopancreas from two to three animals of similar weight was pooled for estimations. The total fat was extracted from the tissue after drying in a hot-air oven for 24 hr, with (3 : 1) ethanol-chloroform and was gravimetrically determined 279
280
a . V. KRISI-INAMOORTHY
e,"~ ,~ ~ +l +1 ~ a', II
" ~ II ~.~:="~
¢, +,~
-B
O
z
8N~
66~
6
eh ~ .,p
~A
+1 +1 ~
8~
~~!
~'~
Irl ~,--I +1 +1 6 m~
O L)
if ~
0
0
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~ ~.i]~ z
I
~6
I +1
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L) I b,
HEPATOPANCREATIC ACIDS D U R I N G AESTIVATION OF PILl1 GLOBOS/I
281
after evaporation of the solvent. Iodine number of fats was determined by the Hanus iodobromide method (Winton & Winton, 1947). Ascorbic acid content was determined by the indophenol titration method (Glick, 1957). A piece of tissue used for ascorbic acid determination was dried separately to find out the water content of the tissue. RESULTS AND DISCUSSION Table 1 summarizes the statistical analysis of the data. Expressed per unit dry weight, there was a highly significant increase in the concentration of ascorbic acid (P = < 0.01) in the hepatopancreas of P. globosa aestivated for 2 months in comparison with that of active snails. This was followed by a highly significant increase in the iodine number (P = < 0.01) of fats on aestivation. The total fat decreased significantly (P = < 0.01) on aestivation in agreement with earlier findings. Changes in the whole tissue mass (P = >0.01) and water content (P = > 0.01) were not significant. The most interesting of the results obtained is a significant increase in the ascorbic acid content in the hepatopancreas during aestivation. Nevertheless, in the absence of any significant change either towards atrophy or hypertrophy in the hepatopancreas during aestivation, the increase in ascorbic acid in this tissue is real and clearly the result of aestivation. Further there is no change in the water content of this tissue as a result of aestivation. Similarly, the change in fat and iodine number in this tissue during aestivation cannot be explained by the change in the total weight. The explanation for these changes must be sought in the fatty acid metabolism of the hepatopancreas during aestivation. Increase in iodine number indicates that the fatty acid oxidation may be blocked by increased amount of the antioxidant, ascorbic acid; this would result in the increase of double bonds. Since it is suggested (George & Desai, 1954) that the fats form a major source of energy during aestivation the decrease in fat content is presumably the result of increased catabolization of fat in the hepatopancreatic tissue during aestivation.
Acknowledgements--I wish to express my gratitude to Dr. K. S. Swami, Head of the Department of Zoology, Sri Venkateswara University, Tirupati, for offering facilities during the course of this investigation. I am also grateful to Messrs. V. Chandrasekharam and T. Ramakrishna for their help during the preparation of this manuscript. I am also grateful to the Council of Scientific and Industrial Research, India, for placing me in the Scientists' Pool. REFERENCES ANJANI PRASADC. ~ KRISHNAMOORTHYR. V. (1962) Catalase activity in normal and aestivated snarl Ariophanta sp.J. Anita. Morph. Physiol. 9, 41-4-5. ECKSTEINB. & ABRAHAMM. (1959) Suecinic dehydrogenase activity in the aestivating and active snails (Helix) Levantina hierosolyma. Physiol. Zool. 32, 210-212. GEORGEJ. C. & DESAI B. N. (1954) On the liver fat in Pi/a globosa (Swainson), J. Anita. Morph. Physiol. 1, 56-58. GLICKD. (1957) Methods of Biochemical Analysis. Vol. 1. Interscience, New York.
282
R. V. KRXSHNAMOORTHY
MEENAKSHIV. R. (1957) Anaerobiosis in the South Indian apple snail Pila virens (Lamarck) during aestivation. ~. Zool. Soc. India 9, 62-71. RAaHUPATHm~aVn PmDDY S. (1965) The charge properties and metabolism of animals exposed to changed environments. Doctoral thesis, Sri Venkateswara University, Tirupati, A.P., India. WmTON A. N. & WmTON K. (1947) Analysis of Foods. Chapman & Hall, London.
SHORT COMMUNICATION HEPATOPANCREATIC UNSATURATED FATTY ACIDS DURING AESTIVATION OF THE SNAIL, P I L A GLOBOSA R. V. K R I S H N A M O O R T H Y Department of Zoology, Sri Venkateswara University, Tirupati, A.P., India
(Received 20 ffune 1967) Abstract--1. Changes in the levels of ascorbic acid, iodine number and percentage fat in the hepatopancreas of Pila globosa, during aestivation were studied. 2. Iodine number of fat and ascorbic acid content were increased in aestivated snails. The percentage fat decreased. 3. It was suggested that the increase in the iodine number of fats might be due to the increased levels of antioxidants like ascorbic acid. INTRODUCTION P~CISE and adequate information about the physiological aspects of aestivation in snails is as yet scantily available. The aestivating snails show reduced oxygen eonsumption (Meenakshi, 1957), reduced flavin metabolism (Anjani Prasad & Krishnamoorthy, 1962) and considerable reduction in succinie dehydrogenase activity (Ekstein & Abraham, 1959). Reduction in the activities of enzymes concerned in carbohydrate metabolism (Raghupathirami Reddy, 1965) has also been reported during aestivation. The sources of energy and causal mechanisms of aestivation are poorly known. Some evidence is available concerning the utilization of accumulated fats (George & Desai, 1954) during aestivation of Pila globosa. In this note the degree of unsaturation of fats during aestivation of P. globosa, which is known to naturally aestivate when ponds dry up, is reported. MATERIAL AND METHODS Pila globosa were collected from the ponds around Tirupati and stocked in laboratory aquaria. One batch of animals was kept in an aquarium at 28°C and the animals of another batch were buried in dry sand in a glass trough and placed in a thermostatically controlled chamber at 35°C in order to aestivate them. After 2 months both active and aestivated animals were sacrified for the estimations. Hepatopancreatic tissue was used. The whole organ was carefully dissected, freed from the gonads and weighed in a Sartorius balance. In some of the experiments, the hepatopancreas from two to three animals of similar weight was pooled for estimations. The total fat was extracted from the tissue after drying in a hot-air oven for 24 hr, with (3 : 1) ethanol-chloroform and was gravimetrically determined 279
280
a . V. KRISI-INAMOORTHY
e,"~ ,~ ~ +l +1 ~ a', II
" ~ II ~.~:="~
¢, +,~
-B
O
z
8N~
66~
6
eh ~ .,p
~A
+1 +1 ~
8~
~~!
~'~
Irl ~,--I +1 +1 6 m~
O L)
if ~
0
0
e,"~ ¢xl
~ ~.i]~ z
I
~6
I +1
Z
L) I b,
HEPATOPANCREATIC ACIDS D U R I N G AESTIVATION OF PILl1 GLOBOS/I
281
after evaporation of the solvent. Iodine number of fats was determined by the Hanus iodobromide method (Winton & Winton, 1947). Ascorbic acid content was determined by the indophenol titration method (Glick, 1957). A piece of tissue used for ascorbic acid determination was dried separately to find out the water content of the tissue. RESULTS AND DISCUSSION Table 1 summarizes the statistical analysis of the data. Expressed per unit dry weight, there was a highly significant increase in the concentration of ascorbic acid (P = < 0.01) in the hepatopancreas of P. globosa aestivated for 2 months in comparison with that of active snails. This was followed by a highly significant increase in the iodine number (P = < 0.01) of fats on aestivation. The total fat decreased significantly (P = < 0.01) on aestivation in agreement with earlier findings. Changes in the whole tissue mass (P = >0.01) and water content (P = > 0.01) were not significant. The most interesting of the results obtained is a significant increase in the ascorbic acid content in the hepatopancreas during aestivation. Nevertheless, in the absence of any significant change either towards atrophy or hypertrophy in the hepatopancreas during aestivation, the increase in ascorbic acid in this tissue is real and clearly the result of aestivation. Further there is no change in the water content of this tissue as a result of aestivation. Similarly, the change in fat and iodine number in this tissue during aestivation cannot be explained by the change in the total weight. The explanation for these changes must be sought in the fatty acid metabolism of the hepatopancreas during aestivation. Increase in iodine number indicates that the fatty acid oxidation may be blocked by increased amount of the antioxidant, ascorbic acid; this would result in the increase of double bonds. Since it is suggested (George & Desai, 1954) that the fats form a major source of energy during aestivation the decrease in fat content is presumably the result of increased catabolization of fat in the hepatopancreatic tissue during aestivation.
Acknowledgements--I wish to express my gratitude to Dr. K. S. Swami, Head of the Department of Zoology, Sri Venkateswara University, Tirupati, for offering facilities during the course of this investigation. I am also grateful to Messrs. V. Chandrasekharam and T. Ramakrishna for their help during the preparation of this manuscript. I am also grateful to the Council of Scientific and Industrial Research, India, for placing me in the Scientists' Pool. REFERENCES ANJANI PRASADC. ~ KRISHNAMOORTHYR. V. (1962) Catalase activity in normal and aestivated snarl Ariophanta sp.J. Anita. Morph. Physiol. 9, 41-4-5. ECKSTEINB. & ABRAHAMM. (1959) Suecinic dehydrogenase activity in the aestivating and active snails (Helix) Levantina hierosolyma. Physiol. Zool. 32, 210-212. GEORGEJ. C. & DESAI B. N. (1954) On the liver fat in Pi/a globosa (Swainson), J. Anita. Morph. Physiol. 1, 56-58. GLICKD. (1957) Methods of Biochemical Analysis. Vol. 1. Interscience, New York.
282
R. V. KRXSHNAMOORTHY
MEENAKSHIV. R. (1957) Anaerobiosis in the South Indian apple snail Pila virens (Lamarck) during aestivation. ~. Zool. Soc. India 9, 62-71. RAaHUPATHm~aVn PmDDY S. (1965) The charge properties and metabolism of animals exposed to changed environments. Doctoral thesis, Sri Venkateswara University, Tirupati, A.P., India. WmTON A. N. & WmTON K. (1947) Analysis of Foods. Chapman & Hall, London.