Changes in trehalase activity and trehalose level during Ascaris suum (Nematoda) embryogenesis

Abstract

130 SummaryThe levels of trehalose and the activity of trehalase during the development of Ascaris suum eggs were investigated. The level of trehalose in the zygote was high (2.96 ± 0.07 mg/g). During cleavage of eggs, it decreased (0.91 ± 0.35 mg/g). A higher concentration of the sugar was recorded at the blastula and during gastrulation, but it did not reach the uncleaved eggs level. In the early motile larvae, the concentration of trehalose was high (4.58 ± 2.01 mg/g). It decreased with development of L 1 larvae (3.10 ± 1.47 mg/g). A rapid increase in trehalose reserves was observed between the L 1 and L 2 stages. The highest content of trehalose was found in invasive L 2 larvae (5.78 ± 1.39 mg/g). The activity of trehalase at the zygote stage was high (560.22 ± 322.31 U/mg). It decreased at the beginning of cleavage. It was the lowest at the 4 -6-cell stage (189.76 ± 114.97 U/mg). An increase in the enzyme activity occurred after reaching the blastula stage (348.44 ± 343.34 U /mg). The highest trehalase activity was recorded during the L 1 larvae stage (635.72 ± 251.16 U/mg). The activity of that enzyme was about three times lower in the invasive stage larvae than in the L 1 larvae.

The gene expression and the activity of enzyme synthesis of trehalose during development ofAscaris suum(Nematoda) eggs

“…The relatively high levels of T6P phosphatase activeity and the mRNA expression during gastrulation were positively correlated with trehalose, accumulation (Dmitryjuk et al 2006). In the tadpole stage, the above was followed by changes in sugar metabolism pathways of Ascaris embryos.…”

“…It was positively correlated with the expression of mRNA. In a previous study (Dmitryjuk et al 2006), L 1 larval production was also accompanied by the accumulation of trehalose, possibly due to high levels of TPP activity in the preceding tadpole stage. Larvae inside an egg consumed trehalose as a source of energy for movement and moulting.…”

“…The situation was stabilized at the blastula stage when the activity of both enzymes was somewhat decreased. Increased trehalose accumulation and higher levels of trehalase activity were observed towards the end of cleavage (Dmitryjuk et al 2006).…”

“…Perhaps the high level of TPP activity is associated with the T6P accumulation during presence of eggs in the uterus. Our earlier observations suggest that in the discussed stage, trehalose is extensively hydrolyzed by trehalase, and its levels remain relatively high (Dmitryjuk et al 2006). According to Fairbairn (1958), trehalose is the main source of energy in early stages of embryonic development.…”

“…Glycogen is the major reserve sugar in Ascaris eggs. Trehalose deserves special attention on account of its unique properties (Żółtowska et al 1998;Dmitryjuk et al 2006).…”