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Age-related glycogen changes in bruchids
Mechanisms of Ageing and Development, 13 (1980) 397-400 © Elsevier Sequoia S.A., Lausanne - Printed in the Netherlands
397
A G E - R E L A T E D G L Y C O G E N C H A N G E S IN B R U C H I D S
SURAJ P. SHARMA and GEETA SHARMA Department of Biology, Guru Nanak Dev University,Amritsar-143005, Punjab (India) (Received March 26, 1980; in revised form June 5, 1980)
SUMMARY Quantitative measurements of glycogen in aging bruchids showed there was a considerable decrease (>50%) with age except on the fifth day when an increase was obseryed, followed by a decrease on the sixth day. The variations in glycogen content with age suggests that glycogen serves as one of the energy sources responsible for the maintenance of metabolism in the process of aging in bruchids.
INTRODUCTION Insect aging results from the depletion and exhaustion of the resources of the adult [1 ]. This finding was later supported by the observation that a decline in energy reserves in female mosquitoes controls longevity [2]. Thus, with increasing age there is a decrease in vitality of the individual. It lias been shown earlier that in bruchids there is a decrease in lipid content with advancing age [3] ; lipids provide energy for the aging bruchids to carry out various metabolic processes in the absence of food intake during their adult life. In addition to lipids, glycogen is another energy reserve in insects [4]. So far studies on glycogen in coleopterans pertain only to embryonic development in Tenebrio molitor [5], and post-embryonic development in T. molitor [6, 7] and Anthonomous grandis [8]. Sakurai [9], working with Coccinella septempunctata, reported that carbohydrates are used as the normal energy source and that lipids are used during starvation. This was later shown also for Cybister confusus [10]. Dudash [11] reported that in the Colorado beetle (Leptinotarsa decemlineata) glycogen accumulated in large amounts in feeding fourth instar larvae and was used during metamorphosis. During pre-diapause feeding, glycogen reserves were replenished again and served as one of the energy sources for the maintenance of metabolism in the hibernating imagoes. The present study on the bruchids Callosobruchus maculatus Fabr. and Zabrotes subfasciatus Boh., was undertaken to correlate the variations in glycogen levels to the aging process. Bruchids are pests of stored products, mostly the seeds of Leguminosae which include mainly pulses. Pulses are a major part of the diet in India, and they are rendered unfit for human consumption by bruchids. During the reproductive cycle the bruchids
398
lay their eggs on the seeds and the larvae mine their way through the testa and tegmen of the seed to settle in the endosperm. Further development up to adult formation takes place within the seed. The bruchids store their total food requirement during development. The adults on emergence do not feed. The bruchids were cultured [12] at 30 + 1 °C. Triplicate samples of 100 mg fresh weight of male bruchids and of female bruchids were taken at 24-h intervals throughout the adult life, Le. from 0-24 hours' old (1 day) to 6 days. Glycogen was extracted by the method of Good et aL [13] and estimated by the method described by Montgomery [14]. As can be seen from Fig. 1, maximum glycogen content was present on the first day after emergence, followed by a decline with increasing age of the bruchids, except on the fifth day when an increase was observed. The decrease in glycogen content from the first to the sixth day was 68.15% and 69.95% in males and females, respectively, of C. maculatus while the decrease in Z. subfasciatus during the same period was 57.27% and 65.25% for males and females, respectively. Thus, with increasing age there is a considerable decrease (>50%) in glycogen content, though the range differs in males and females. The decrease is more pronounced in females than males as the former have a high physical and metabolic activity in terms of movement, flight and egg-laying capacity. This suggests that glycogen is utilized as an energy source for the various metabolic processes in the bruchids. .27
"36 -1-
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~.16 o U
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•06
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A ~ (DAys) Fig. 1, Quantitative measurements of glycogen content in aging bruehids (male and female).
399 A decrease in glycogen content in aging Drosophila has been shown by Miquel et al. [15], Takahashi et al. [16] and Miquel [17] using histochemical methods. Furthermore, an electron-microscopic study of Simon et al. [18] demonstrated complete disappearance of glycogen granules in the flight muscles of houseflies beyond 12 days of age. Samis et al. [19] observed a fall of about 50% in the glycogen level in both sexes ofD. melanogaster with advancing age. Sohal [20] recorded a decrease in glycogen in the abdominal fat body ceUs o f M u s c a domestica. A marked decrease in glycogen was also observed in the photogenic layer of firefly lantern by Press et al. [22]. On the fifth day after emergence, the glycogen level rises by 27.53% and 21.64% in males and females of C. maculatus and 39.51% and 29.68% in males and females of Z. subfasciatus. This increase in glycogen content about two days prior to death is a unique phenomenon observed in these bruchids. The increase in glycogen content may be attributed to increased synthesis of glycogen as an attempt to maintain the vitality of the body and seems to be a last resort to escape death. Probably, there is interconversion of lipids to glycogen and this could account for the increase in glycogen on the fifth day. But death occurs because by the sixth day the glycogen content falls, decreasing the vitality beyond the minimum level needed to sustain life. The age-related fall in the glycogen level, accompanied by decreasing lipid content [3] and diminished protein-synthesizing capacity [21], results in exhaustion of the maintenance capacity of the adult bruchids, showing that glycogen serves as one of the energy sources for the maintenance of metabolism in the aging process of bruchids. This supports the view that insect aging results from depletion and exhaustion of energy resources [1, 2]. Aging in these bruchids seems to be a homeostatic process which fails when a minimum level of vitality is reached.
REFERENCES 1 R. Pearl, The Rate of Living. Being an Account of Some Experimental Studies on the Biology of Life Duration, Knopf, New York, 1928. 2 J. K. Nayar and D. M. Saurman, A comparative study of flight performance and fuel utilization as a function of age in females of Florida (U,S.A.) mosquitoes (Dipt., Culicidae). J. Insect Physiol., 19 (1973) 1977-1988. 3 S. P. Sharma and G. Sharma, Age-related lipid studies in bruchids. C~urr.ScL, 48 (1979) 955-956. 4 G. R. Wyatt, The biochemistry of sugars and polysaecharides in insects. Adv. Insect Physiol., 4 (1967) 287-360. 5 D. Ludwig and L. J. Ramazzotto, Energy sources during embryogenesisof the yellow mealworm, Tenebrio molitor. Ann. Entomol. Soc. Am., 58 (1965) 543-546. 6 P. G. Rousell, Determination of glycogen content during the metamorphosis of the mealworm (Tenebrio molitor L.). J. iV. Y. Entomol. Sac., 63 (1955) 107-110. 7 J. Dutrieu and L. Gourdoux, Trehalose and glycogen during development of Tenebrio molitor. C. R. Seances Sac. Biol. Filiales, 164 (1971) 1994-1999. 8 W. C. Neetles and N. L. Betz, Glycogen in the boll weevil with respect to diapause, age and diet. Ann. Entomol. Sac. Am., 58 0965) 721-726. 9 H. Sakurai, Utilization of energy source in the adults of Caccinella septempunctata bruckii Mulsant (Coleoptera:'Coccinellida¢).Kontyu, 37 (1969) 167-171. 10 V. L. KaUapur, A compartive study of leg and flight muscles of the beetle Cybister confusus (Diptiscidae, Coleoptera) with reference to their fibre diameter and fat, glycogen, succinic dehydrogenase and lipase content. J. Anim. Morphol. Physiol., 17 (1970) 37--43.
400 11 A. V. Dudash, Glycogen content in the fat body of the Colorado beetle (Leptinotarsa decemlineata). Zool. Zh., 57 (1978) 695-699. 12 S. P. Sharma, S. Rattan and G. Sharma, Temperature dependent longevity of Zabrotes subfasciatus Boh. (Coleoptera - Bruchidae). Comp. Physiol. Ecol., 4 (1979) 229-231. 13 C. A. Good, H. Kremer and M. Somogyi, The determination of glycogen. J. Biol. Chem., 100 (1935) 485-491. 14 R. Montgomery, Determination of glycogen. Arch. Biochem. Biophys., 67 (1957) 378-386. 15 J. Miquel, F. Hobbisie~en and J. Duffy, Age differences in the glycogen content of nervous and muscle tissue of Drosophila melanogaster. Gerontologist, 7 (1965) 17. 16 A. Takahashi, D. E. Philpott and J. Miquel, Electron microscope studies on aging Drosophila melanogaster. III. Flight muscle. J. Gerontol., 25 (1970) 222-228. 17 J. Miquel, Aging of male DrosoPhila melanogaster: Histological, histochemical and ultrastructural observations. Adv. Gerontol. Res., 3 (1971) 39-71. 18 J. P. Simon, L. Bhatnagar and N. S. Milburn, An electron miscroscope study of changes in mitochondria of flight muscle of aging houseflies (Musca domestica). J. Insect Physiol., 15 (1969) 135-140. 19 H.V. Samis Jr., F. C. Erk and M. B. Baird, Senescence in Drosophila - I. Sex differences in nucleic acids, protein and glycogen levels as a function of age. Exp. Gerontol., 6 (1971) 9-18. 20 R. S. Sohal, Fine structural alterations with age in fat body of the adult male housefly Musca domestica (Dipt., Muscidae). Z. Zellforsch., 140 (1973) 169-175. 21 S. P. Sharma and G. Sharma, Age-related protein changes in bruchids. Indian J. Exp. Biol., 17 (1979) 1197-1200. 22 G. D. Press, A. Raychauduri and B. L. Strehler, Histochemical changes in the firefly lantern during the ageing process. J. Gerontol., 21 (1966) 13-21.
397
A G E - R E L A T E D G L Y C O G E N C H A N G E S IN B R U C H I D S
SURAJ P. SHARMA and GEETA SHARMA Department of Biology, Guru Nanak Dev University,Amritsar-143005, Punjab (India) (Received March 26, 1980; in revised form June 5, 1980)
SUMMARY Quantitative measurements of glycogen in aging bruchids showed there was a considerable decrease (>50%) with age except on the fifth day when an increase was obseryed, followed by a decrease on the sixth day. The variations in glycogen content with age suggests that glycogen serves as one of the energy sources responsible for the maintenance of metabolism in the process of aging in bruchids.
INTRODUCTION Insect aging results from the depletion and exhaustion of the resources of the adult [1 ]. This finding was later supported by the observation that a decline in energy reserves in female mosquitoes controls longevity [2]. Thus, with increasing age there is a decrease in vitality of the individual. It lias been shown earlier that in bruchids there is a decrease in lipid content with advancing age [3] ; lipids provide energy for the aging bruchids to carry out various metabolic processes in the absence of food intake during their adult life. In addition to lipids, glycogen is another energy reserve in insects [4]. So far studies on glycogen in coleopterans pertain only to embryonic development in Tenebrio molitor [5], and post-embryonic development in T. molitor [6, 7] and Anthonomous grandis [8]. Sakurai [9], working with Coccinella septempunctata, reported that carbohydrates are used as the normal energy source and that lipids are used during starvation. This was later shown also for Cybister confusus [10]. Dudash [11] reported that in the Colorado beetle (Leptinotarsa decemlineata) glycogen accumulated in large amounts in feeding fourth instar larvae and was used during metamorphosis. During pre-diapause feeding, glycogen reserves were replenished again and served as one of the energy sources for the maintenance of metabolism in the hibernating imagoes. The present study on the bruchids Callosobruchus maculatus Fabr. and Zabrotes subfasciatus Boh., was undertaken to correlate the variations in glycogen levels to the aging process. Bruchids are pests of stored products, mostly the seeds of Leguminosae which include mainly pulses. Pulses are a major part of the diet in India, and they are rendered unfit for human consumption by bruchids. During the reproductive cycle the bruchids
398
lay their eggs on the seeds and the larvae mine their way through the testa and tegmen of the seed to settle in the endosperm. Further development up to adult formation takes place within the seed. The bruchids store their total food requirement during development. The adults on emergence do not feed. The bruchids were cultured [12] at 30 + 1 °C. Triplicate samples of 100 mg fresh weight of male bruchids and of female bruchids were taken at 24-h intervals throughout the adult life, Le. from 0-24 hours' old (1 day) to 6 days. Glycogen was extracted by the method of Good et aL [13] and estimated by the method described by Montgomery [14]. As can be seen from Fig. 1, maximum glycogen content was present on the first day after emergence, followed by a decline with increasing age of the bruchids, except on the fifth day when an increase was observed. The decrease in glycogen content from the first to the sixth day was 68.15% and 69.95% in males and females, respectively, of C. maculatus while the decrease in Z. subfasciatus during the same period was 57.27% and 65.25% for males and females, respectively. Thus, with increasing age there is a considerable decrease (>50%) in glycogen content, though the range differs in males and females. The decrease is more pronounced in females than males as the former have a high physical and metabolic activity in terms of movement, flight and egg-laying capacity. This suggests that glycogen is utilized as an energy source for the various metabolic processes in the bruchids. .27
"36 -1-
_~.3:, 3:
t__~
F T STANOARO L-- I DEWArIO,
•2 4
I1W
•21
~r
~
=6 IJ
I2
w .,..I
Z w
"~ ~E
~.16 o U
0
'"
U
._l
.09 ~ ~
•06
~
•0 3
'~
Z w
A ~ (DAys) Fig. 1, Quantitative measurements of glycogen content in aging bruehids (male and female).
399 A decrease in glycogen content in aging Drosophila has been shown by Miquel et al. [15], Takahashi et al. [16] and Miquel [17] using histochemical methods. Furthermore, an electron-microscopic study of Simon et al. [18] demonstrated complete disappearance of glycogen granules in the flight muscles of houseflies beyond 12 days of age. Samis et al. [19] observed a fall of about 50% in the glycogen level in both sexes ofD. melanogaster with advancing age. Sohal [20] recorded a decrease in glycogen in the abdominal fat body ceUs o f M u s c a domestica. A marked decrease in glycogen was also observed in the photogenic layer of firefly lantern by Press et al. [22]. On the fifth day after emergence, the glycogen level rises by 27.53% and 21.64% in males and females of C. maculatus and 39.51% and 29.68% in males and females of Z. subfasciatus. This increase in glycogen content about two days prior to death is a unique phenomenon observed in these bruchids. The increase in glycogen content may be attributed to increased synthesis of glycogen as an attempt to maintain the vitality of the body and seems to be a last resort to escape death. Probably, there is interconversion of lipids to glycogen and this could account for the increase in glycogen on the fifth day. But death occurs because by the sixth day the glycogen content falls, decreasing the vitality beyond the minimum level needed to sustain life. The age-related fall in the glycogen level, accompanied by decreasing lipid content [3] and diminished protein-synthesizing capacity [21], results in exhaustion of the maintenance capacity of the adult bruchids, showing that glycogen serves as one of the energy sources for the maintenance of metabolism in the aging process of bruchids. This supports the view that insect aging results from depletion and exhaustion of energy resources [1, 2]. Aging in these bruchids seems to be a homeostatic process which fails when a minimum level of vitality is reached.
REFERENCES 1 R. Pearl, The Rate of Living. Being an Account of Some Experimental Studies on the Biology of Life Duration, Knopf, New York, 1928. 2 J. K. Nayar and D. M. Saurman, A comparative study of flight performance and fuel utilization as a function of age in females of Florida (U,S.A.) mosquitoes (Dipt., Culicidae). J. Insect Physiol., 19 (1973) 1977-1988. 3 S. P. Sharma and G. Sharma, Age-related lipid studies in bruchids. C~urr.ScL, 48 (1979) 955-956. 4 G. R. Wyatt, The biochemistry of sugars and polysaecharides in insects. Adv. Insect Physiol., 4 (1967) 287-360. 5 D. Ludwig and L. J. Ramazzotto, Energy sources during embryogenesisof the yellow mealworm, Tenebrio molitor. Ann. Entomol. Soc. Am., 58 (1965) 543-546. 6 P. G. Rousell, Determination of glycogen content during the metamorphosis of the mealworm (Tenebrio molitor L.). J. iV. Y. Entomol. Sac., 63 (1955) 107-110. 7 J. Dutrieu and L. Gourdoux, Trehalose and glycogen during development of Tenebrio molitor. C. R. Seances Sac. Biol. Filiales, 164 (1971) 1994-1999. 8 W. C. Neetles and N. L. Betz, Glycogen in the boll weevil with respect to diapause, age and diet. Ann. Entomol. Sac. Am., 58 0965) 721-726. 9 H. Sakurai, Utilization of energy source in the adults of Caccinella septempunctata bruckii Mulsant (Coleoptera:'Coccinellida¢).Kontyu, 37 (1969) 167-171. 10 V. L. KaUapur, A compartive study of leg and flight muscles of the beetle Cybister confusus (Diptiscidae, Coleoptera) with reference to their fibre diameter and fat, glycogen, succinic dehydrogenase and lipase content. J. Anim. Morphol. Physiol., 17 (1970) 37--43.
400 11 A. V. Dudash, Glycogen content in the fat body of the Colorado beetle (Leptinotarsa decemlineata). Zool. Zh., 57 (1978) 695-699. 12 S. P. Sharma, S. Rattan and G. Sharma, Temperature dependent longevity of Zabrotes subfasciatus Boh. (Coleoptera - Bruchidae). Comp. Physiol. Ecol., 4 (1979) 229-231. 13 C. A. Good, H. Kremer and M. Somogyi, The determination of glycogen. J. Biol. Chem., 100 (1935) 485-491. 14 R. Montgomery, Determination of glycogen. Arch. Biochem. Biophys., 67 (1957) 378-386. 15 J. Miquel, F. Hobbisie~en and J. Duffy, Age differences in the glycogen content of nervous and muscle tissue of Drosophila melanogaster. Gerontologist, 7 (1965) 17. 16 A. Takahashi, D. E. Philpott and J. Miquel, Electron microscope studies on aging Drosophila melanogaster. III. Flight muscle. J. Gerontol., 25 (1970) 222-228. 17 J. Miquel, Aging of male DrosoPhila melanogaster: Histological, histochemical and ultrastructural observations. Adv. Gerontol. Res., 3 (1971) 39-71. 18 J. P. Simon, L. Bhatnagar and N. S. Milburn, An electron miscroscope study of changes in mitochondria of flight muscle of aging houseflies (Musca domestica). J. Insect Physiol., 15 (1969) 135-140. 19 H.V. Samis Jr., F. C. Erk and M. B. Baird, Senescence in Drosophila - I. Sex differences in nucleic acids, protein and glycogen levels as a function of age. Exp. Gerontol., 6 (1971) 9-18. 20 R. S. Sohal, Fine structural alterations with age in fat body of the adult male housefly Musca domestica (Dipt., Muscidae). Z. Zellforsch., 140 (1973) 169-175. 21 S. P. Sharma and G. Sharma, Age-related protein changes in bruchids. Indian J. Exp. Biol., 17 (1979) 1197-1200. 22 G. D. Press, A. Raychauduri and B. L. Strehler, Histochemical changes in the firefly lantern during the ageing process. J. Gerontol., 21 (1966) 13-21.