Synthesis and deposition of chitin in larvae of the Australian sheep blowfly, <i>Lucilia cuprina</i>

Retnakaran, Arthur; Hackman, R.H.

doi:10.1002/arch.940020304

Cited by 15 publications

(4 citation statements)

References 20 publications

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“…Although UDP-GlgNAc is the immediate substrate for chitin synthase GlcN and GlcNAc are incorporated into chitin by homogenates from Chironomus cells. This is described also for enzyme preparations from the epidermis of Lucilia cuprinu [33,34]. Whether GlcN and GlcNAc enter the chitin synthesis pathway after acetylation and phosphorylation by enzymes present in the homogenate via UDP-GlcNAc or whether there exists an additiona1 alternative pathway [35] remains unknown.…”

Section: Discussionmentioning

confidence: 99%

Properties of chitin synthase in homogenates from Chironomus cells

Ludwig

Spindler-Barth

Spindler

1991

Arch Insect Biochem Physiol

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Homogenates of Chironomus cells synthesize chitin as effectively as intact cells. Chitin is produced in a dose-dependent manner, when GlcN, ClcNAc, or UDPGlcNAc is used as precursor. Due to the lability of UDP-GlcNAc incorporation of this substrate is underestimated. N o allosteric effect i s observed when ClcN or GlcNAc is used as a substrate. Chitin synthesis is stimulated by Mg2+ and inhibited by uridine monophosphate (UMP), uridine diphosphate (UDP), and uridine triphosphate (UTP). The apparent temperature optimum is 30"C, the apparent p H optimum is 5.5-6. Addition of the chitinase inhibitor allosamidin does not enhance chitin synthesis significantly. The time course of chitin formation reveals a lag period of about 12 h, which can be overcome by t rypsi n treatment . Addition of protease i n h i bitors prevents chitin synthesis .

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Section: Discussionmentioning

confidence: 99%

Properties of chitin synthase in homogenates from Chironomus cells

Ludwig

Spindler-Barth

Spindler

1991

Arch Insect Biochem Physiol

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“…The potential of acylureas as integrated pest control agents has received considerable attention in the last three decades. This group of insecticides disrupts the ecdysis of insect larvae by inhibiting chitin deposition in the cuticle during growth and development (Retnakaran & Hackman, 1985). In some species of Lepidoptera, these induced morphological disruptions result in ecdysis failure, blackening, integument rupture, and fluid loss, depending on the species (Omatsu et al., 1991).…”

Section: Introductionmentioning

confidence: 99%

Effects of residual chlorfluazuron on haemolymph‐borne oviposition‐stimulating factors in Spodoptera litura

Perveen¹

2009

Entomologia Exp Applicata

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Acylurea insecticides can have various effects on insect reproduction and may even interfere with haemolymph‐borne oviposition‐stimulating factors (OSFs). This study describes the effects of injecting haemolymph into females of the common cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae), the effects of chlorfluazuron on the activities of OSFs, when sublethal doses (LD10: 1.00 ng larva−1 or LD30: 3.75 ng larva−1) were applied topically to newly ecdysed fifth instars under laboratory conditions. The haemolymph of moths of varying age, sex, and mating status resulted in the following increases in oviposition rates within the first 24 h, listed in decreasing order: the haemolymph of mated females injected into mated females (56%), mated females into newly emerged virgin females (53%), virgin males into virgin females (49%), and virgin females into mated females (29%), compared with uninjected mated or virgin females. Two factors are involved in the activation of ovipositon: OSF‐I is found in virgin females, whereas OSF‐II may be formed or received by males during mating. By contrast, the haemolymph taken from chlorfluazuron‐treated adults (treated as fifth instars with sublethal doses) injected into females resulted in the following percentage decreases in oviposition rates within the first 24 h, listed in decreasing order: the haemolymph of LD10‐ and LD30‐treated virgin males injected into untreated virgin females (77 and 84%, respectively), LD10 and LD30‐treated virgin females into untreated mated females (70 and 80%, respectively), LD10 and LD30‐treated mated females into untreated mated females (61 and 69%, respectively), LD10 and LD30‐treated mated females into untreated virgin females (59 or 68%, respectively), compared with untreated ones. Hence, residual chlorfluazuron decreases the activities of OSFs by significantly decreasing the oviposition rates. Moreover, virgin females’ or males’ OSFs are more sensitive to chlorfluazuron than those of mated cutworms. Both OSFs are most likely proteins.

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“…The use of acyl urea compounds as insect pest control agents has received considerable attention over the last three decades (Perveen & Miyata 2000). One class of these compounds, employed as insect growth regulators, disrupts the moulting process of larvae by inhibiting chitin deposition in their cuticles during growth and development (Retnakaran & Hackman 1985). This inhibition induces morphological abnormalities during moulting, a characteristic effect of this class of insecticides.…”

Section: Introductionmentioning

confidence: 99%

Effects of sublethal doses of chlorfluazuron on insemination and number of inseminated sperm in the common cutworm, Spodoptera litura (F.) (Lepidoptera: Noctuidae)

Perveen

2008

Entomological Science

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Sublethal doses (LD10: 1.00 ng larva -1 ; or LD30: 3.75 ng larva -1 ) of chlorfluazuron were applied topically to the cuticles of newly moulted fifth instars of the common cutworm, Spodoptera litura (F.) (Lepidoptera, Noctuidae). During mating, the treated males transferred spermatophores of a significantly lower weight into females. The weight of spermatophores transferred by LD30-treated males was significantly lower than the weight of spermatophores transferred by LD10-treated males, which was in turn significantly lower than the weight of spermatophores transferred by untreated males. The transfer of spermatophores was delayed by 5-15 min in LD10-and LD30-treated males. However, mating duration was not affected by chlorfluazuron treatment. The transfer of spermatozoa was also delayed by 5-10 min in LD10-and LD30-treated females. Polygynous male adults mated an average of ten times during their lifespan of 11-13 days when paired every day with a new virgin female of the same age. The number of matings per polygynous male was not affected by chlorfluazuron treatment, but the first mating was delayed by 1 day. The number of inseminated sperm found in the spermatophore averaged 10.3 (Ϯ 2.1) ¥ 10 5 over the lifespan of a male, in which the number of eupyrene sperm was 5.4 (Ϯ 1.1) ¥ 10 5 . The number of inseminated eupyrene sperm decreased by 66% and 88%, respectively, in LD10-and LD30-treated males. No significant reduction in the number of inseminated eupyrene sperm was observed when females were treated with LD10 or LD30 doses, nor was there a significant reduction when both sexes were treated with the LD10 or LD30 doses relative to treatment of males with the same doses. The ratio of inseminated eupyrene to apyrene sperm was not affected by chlorfluazuron treatment.

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Synthesis and deposition of chitin in larvae of the Australian sheep blowfly, Lucilia cuprina

Cited by 15 publications

References 20 publications

Properties of chitin synthase in homogenates from Chironomus cells

Properties of chitin synthase in homogenates from Chironomus cells

Effects of residual chlorfluazuron on haemolymph‐borne oviposition‐stimulating factors in Spodoptera litura

Effects of sublethal doses of chlorfluazuron on insemination and number of inseminated sperm in the common cutworm, Spodoptera litura (F.) (Lepidoptera: Noctuidae)

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