The level of chitinolytic enzymes and ecdysteroids during larval-pupal development in Ephestia cautella and their modifications by a juvenile hormone analogue

Spindler-Barth, Margarethe; Shaaya, Eli; Spindler, Klaus-Dieter

doi:10.1016/0020-1790(86)90095-8

Cited by 26 publications

(4 citation statements)

References 19 publications

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“…Accordingly, the molecular turnover of chitin plays an important role in the energy metabolism of the arthropods. Furthermore, chitinolytic enzymes can serve as biochemical markers for the moulting cycle, since a close correlation has been shown in a few species between the titer of moulting hormones and the titer of these enzymes (Baler and Scheffel 1984;Spindler-Barth et al 1986; for a review see Spindler 1983). …”

Section: Introductionmentioning

confidence: 98%

Partial characterization of chitin degrading enzymes from two euphausiids, Euphausia superba and Meganyctiphanes norvegica

Spindler

Búchholz

1988

Polar Biol

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Summary. Chitinase and N-acetyl-~-D-glucosaminidasehave been demonstrated in Meganyctiphanes norvegica and in Euphausia superba and partly characterized. The enzymes from both species have broad pH-optima (maxima around pH 5.0) and temperature optima between 40 and 50°C. The enzymes are relatively stable; even at about 45 °C half of the enzyme activity is retained after 30 min incubation. The presence of fluoride does not affect enzymatic activity. Chitinase activity appears in three different molecular masses, N-acetyl-[~-D-glucosaminidases in two different forms, pH and temperature optima, thermal stability and kinetic properties of the two enzymes are strikingly similar in the polar E. superba versus the boreal euphausiid M. norvegica. Enzyme activity in the lower temperature range is still high, whereas activation energies are low in both euphausiids. This suggests a functional adaptation to a low temperature range in seawater.

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Section: Introductionmentioning

confidence: 98%

Partial characterization of chitin degrading enzymes from two euphausiids, Euphausia superba and Meganyctiphanes norvegica

Spindler

Búchholz

1988

Polar Biol

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“…Unfortunately, such relationships are rarely established, and in practice enzyme activities vary simply with body size (Bergcs et al 1992). For chitinase and chitobiase, however, activities modulate strongly over the molt cycle in several species (Spindler-Barthe et al 1986;Bucholz 1989;Espie and Roff 1995), increasing up to 12-fold before molting. Of the two enzymes, the assay for chitobiase is much simpler.…”

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confidence: 99%

A biochemical index of duration of the molt cycle for planktonic Crustacea based on the chitin‐degrading enzyme, chitobiase

Espie

Roff

1995

Limnology & Oceanography

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The activity of chitobiase over an entire molt cycle was measured in Daphnia magna; it increased by 5-fold from intermolt to premolt (when animals are in apolysis). Duration of the entire molt cycle increased about 3-fold with a decrease in temperature from 25 to 6"C, but increased by <2-fold over an go-fold difference in food concentration. There was a strong (r2 = 0.95) linear relationship between chitobiase activity and duration of the molt cycle, as modulated by food concentration, in asynchronous populations of D. magna. The relationship between chitobiase activity and duration of the molt cycle, as modulated by temperature, was also highly significant (r2 = 0.77) but nonlinear. The relationship between chitobiase activity and temperature is also nonlinear (r 2 = 0.67). A significant linear relationship between chitobiase activity and duration of the molt cycle was also found for a natural population ofDaphnia rosea (r2 = 0.88). Regressions of enzyme activity with body size and glucosamine content for three species of Daphnia indicate that differences exist between species. Chitobiase activity is an index of the proportion of animals in apolysis in a population. Because this proportion changes as a function of food concentration, but apparently not as a function of temperature, chitobiase activity is a measure of the duration of the molt cycle as limited by food concentration.

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“…20-Hydroxyecdysone and [23,24-3H] ecdysone, specific activity 68 Ci/mmol, was supplied by Sigma, St. Louis, MO. Extraction and quantitative determination by radioimmunoassay of ecdysteroids were performed according to Spindler-Barth et al [16]. RNA was extracted as described by Shaaya [17] and separated by gel electrophoresis according to Shaaya [18].…”

Section: Chemicalsmentioning

confidence: 99%

“…9). When methoprene was applied topically on the first day of the pupal stage, it had no effect on ecdysteroid titer and there was no difference between control and treated insects' specific enzyme activities [16]. It should be mentioned, however, that methoprene given in this developmental stage is lethal because it interferes with the process of pupal adult differentiation [B].…”

Section: Influence Of Methoprene On the Activity Of Chitinolytic Enzymesmentioning

confidence: 99%

Interference of the insect growth regulator methoprene in the process of larval‐pupal differentiation

Shaaya

1993

Arch Insect Biochem Physiol

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Studies with epidermal cells of a number of insects showed that a sequence of physiological events takes place prior to and during the process of commitment of the epidermal cells from the larval to the pupal stage. At the onset of metamorphosis RNA synthesis, including that of RNA, was suppressed for about 30 h just prior to the wandering stage. At the completion of the wandering stage, pupally committed epidermal cells synthesize a new type of RNA termed hetero-disperse nuclear RNA (hnRNA). It is suggested that this RNA species could play a role in the permanent shutting-off of larval-specific genes. Methoprene, a juvenile hormone analogue (JHA), delayed the larval-pupal transformation and prevented these changes in RNA synthesis when applied prior to the appearance of the hnRNA, but had no effect when applied after this period. Treatment with the ]HA in the early last larval instar prevented not only the normal rise in ecdysteroid titer, but also the increase in the activity of chitinolytic enzymes. Treatment of young pupae had no effect on either the ecdysteroids titer or on enzyme activity. A causal relationship between molting hormone titer and the activity of chitinolytic enzymes is proposed. o 1993 WiIey-Liss, Inc.

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The level of chitinolytic enzymes and ecdysteroids during larval-pupal development in Ephestia cautella and their modifications by a juvenile hormone analogue

Cited by 26 publications

References 19 publications

Partial characterization of chitin degrading enzymes from two euphausiids, Euphausia superba and Meganyctiphanes norvegica

Partial characterization of chitin degrading enzymes from two euphausiids, Euphausia superba and Meganyctiphanes norvegica

A biochemical index of duration of the molt cycle for planktonic Crustacea based on the chitin‐degrading enzyme, chitobiase

Interference of the insect growth regulator methoprene in the process of larval‐pupal differentiation

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