Embryonic and post-emergence changes of acid and alkaline phosphatases in the cotton leaf worm, Spodoptera littoralis (Boisd.)

Zahia Mostafa,Eman Rashad,Sondos Mohamed

doi:10.21608/eajbsa.2009.15509

Abstract

The acid and alkaline phosphatase activities were studied in the de veloping egg of the cotton leaf worm, Spodoptera littoralis at different time intervals (ages, 0 72 h). The activities of these enzymes were also studied in aging ovary and testi s of post-emerged adult at the same intervals (ages, 0 – 72 h). The post-emerged adults were grouped into mated and non-mated females and males. Acid phosphatase activity was noticed to be cyclic with the embryonic development and was higher than that of alkaline phosphatase. Alkaline phosphatase activity was slightly increased in the freshly laid egg s but decreased more sharply than acid phosphatase during embryonic development. In all groups of post -emerged adults, acid phosphatase activities were much greater than those of the alkaline phosphatase at any given stage of progressively increasing age. Acid and alkaline phosphatase activities were also noticed to be cyclic in the post -emerged mated and non-mated adults. A conspicuous difference was noted between the activities of these enzymes in ovaries and testes of mated and non-mated adults. This phenomenon could be due to the periods of spermatozoa production in the testes and yolk accumulation in oocytes and ovulation. Mating could be also a factor that affected the phosphatases in both males and females.

Highlights

Eggs of most insect species have special organelles, called yolk spheres, filled with protein that is the most important reserve of amino acids for the embryo development during embryogenesis
I- Embryonic changes of acid and alkaline phosphatases: The activity of both acid and alkaline phosphatase was studied in S. littoralis eggs at different ages during the course of embryonic development
At the age of 72h, the alkaline phosphatase activity was slightly increased. It was indicative from the present observations that the activity of acid phosphatase was higher than of alkaline phosphatase during the course of embryonic development

Summary

Introduction

Eggs of most insect species have special organelles, called yolk spheres, filled with protein (vitellin) that is the most important reserve of amino acids for the embryo development during embryogenesis. After oocyte fertilization and during embryogenesis an intensive protein metabolism take place which involves mainly break down of pre-existing yolk reserves (vitellin) and the conversion of these into tissue and organ specific proteins. Several enzymes involved in this process have been characterized in the past years (Fagotto, 1990; Yamamoto and Takahashi, 1993; Izumi et al, 1994; Liu et al, 1996; Cho et al, 1999). The role of acid phosphatase in processing of yolk during development was first recognized by Lemanski and Aldoroty (1974). Alkaline phosphatase (EC. 3.1.3.1) is known to cause the breakdown of cytoplasmic inclusion during embryogenesis and at the same time the products of this process transform in some way the morphogenetic property of the cleavage energids which later become included in the primordial cells (Seidel, 1936; 1960)

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Conclusion