An in vitro system for the quantitative measurement of chitin synthesis in the cockroach: Inhibition by TH 6040 and polyoxin D

Sowa, Bogusław; Marks, Edwin P.

doi:10.1016/0020-1790(75)90030-x

Cited by 74 publications

(14 citation statements)

References 7 publications

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“…The apparent Iso for diflubenzuron (7 x 1O-7 M) is similar to the value of 5·5 x 1O-7 M obtained by Hajjar and Casida (1978) using abdomens of the milkweed bug (Oncopeltus fasciatus) but is somewhat higher than the level of 6·9 x 1O-8 M calculated by Sowa and Marks (1975) to be the effective concentration of diflubenzuron within the cells of regenerating cockroach leg. Polyoxin-D (apparent Iso, 6 x 1O-7 M) was considerably more potent in our system than in that used by Hajjar and Casida (1978) (Iso,1·2 x IO-S M) but an Iso value of '7·5 X 10-7 M, similar to ours, was obtained by Sowa and Marks (1975).…”

Section: Discussionsupporting

confidence: 79%

“…Because UDPAG is the final intermediate in the pathway from NAG to chitin, this result suggests that it does not easily penetrate the cell membrane to enter epidermal cells. A similar suggestion was made by Sowa and Marks (1975).…”

Section: Characteristics Of Chitin Synthesis By Larval Integumentssupporting

confidence: 82%

“…Oberlander and Leach (1975) also studied the uptake and incorporation of eH]glucosamine into cuticle under the influence of (1.-and fi-ecdysone in this culture system. Sowa and Marks (1975) used cultured regenerating cockroach legs to study fi-ecdysone-stimulated chitin synthesis from N-[1-14 C]acetylglucosamine. This incorporation was prevented by chitin synthesis inhibitors.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Several Larvicidal Compounds on Chitin Biosynthesis by Isolated Larval Integuments of the Sheep Blowfly Lucilia cuprina

Turnbull¹,

Howells²

1982

Aust. Jnl. Of Bio. Sci.

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Isolated whole integuments from L. cuprina larvae rapidly incorporate radioactivity from both N-acetyl[I-'4C]glucosamine and [1-'4C]glucosamine into alkali-insoluble material, a reaction which does not require preincubation of the tissue with /i-ecdysone. The labelled product was degraded to N-acetylglucosamine during digestion with chitinase, establishing that it consists mainly of chitin. Incorporation was inhibited by polyoxin-D (Iso, 6 x 10-7 M) and diflubenzuron (Iso, 7 x 10-7M) but was not inhibited to any marked extent by isoprothiolane, Vetrazin or a-methyl-DOPA. The effectiveness of diflubenzuron as an inhibitor of chitin synthesis in this system (Iso, 7 x 10-7 M) correlates well with its potency as a larvicide (LDso, 2·1 x 10-6 M), providing additional support for the proposal that this compound kills larvae by interfering with chitin deposition in the cuticle. Polyoxin-D was much more effective as an inhibitor of chitin synthesis (Iso, 6 x 10-7 M) than as a larvicide (LDso, 2·0x 10-5 M). It was established that the final intermediate of chitin biosynthesis (UDP-N-acetylglucosamine) was formed in the isolated integuments in the presence of diflubenzuron and polyoxin-D. It seems likely therefore that both compounds interfere with the final polymerization step of the chitin biosynthesis pathway.

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Section: Discussionsupporting

confidence: 79%

Section: Characteristics Of Chitin Synthesis By Larval Integumentssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Effects of Several Larvicidal Compounds on Chitin Biosynthesis by Isolated Larval Integuments of the Sheep Blowfly Lucilia cuprina

Turnbull¹,

Howells²

1982

Aust. Jnl. Of Bio. Sci.

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“…A piece of integument excised from a living specimen was incubated in a culture medium containing the antibiotic. Polyoxin D inhibited the chitin synthesis in the cultured tissue of lepidopteran (Nishioka et al, 1979;Kaska et al, 1980;Kitahara et al, 1983;Gelman and Borkovec, 1986), blattodean (Sowa and Marks, 1975;Nakagawa et al, 1993), and dipteran (van Eck, 1979;Becker, 1980;Mayer et al, 1980a;Turnbull and Howells, 1982) insects.…”

Section: Introductionmentioning

confidence: 99%

Insecticidal effect of a fungicide containing polyoxin B on the larvae of Bombyx mori (Lepidoptera: Bombycidae), Mamestra brassicae, Mythimna separata, and Spodoptera litura (Lepidoptera: Noctuidae)

Arakawa

Yukuhiro

Noda

2008

Appl. Entomol. Zool.

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The insecticidal effect of a water-soluble powder of Polyoxin AL, a fungicide that inhibits chitin synthase, on the larvae of Bombyx mori, Mamestra brassicae, Mythimna separata, and Spodoptera litura was examined. After the fungicide was mixed in diet and applied orally, all the larvae of S. litura, M. separata, and M. brassicae died at the molting stage at polyoxin levels of 0.03, 0.1, and 0.3% (wt/wt), respectively. A morphological study with S. litura showed that the larvae to which Polyoxin AL was orally applied failed to form a new cuticle. The median lethal concentration (LC 50 ) of Polyoxin AL in S. litura 3rd stadium larvae was approximately 0.02%. Polyoxin AL had little effect on B. mori, even at 0.3% in the diet. The standard chemicals polyoxin B, polyoxin D, and nikkomycin Z were applied orally to S. litura 3rd stadium larvae. All the larvae were killed after exposure to 0.005% polyoxin B and 0.015% nikkomycin Z. Polyoxin D, however, had no effect even at 0.015%. Polyoxin B and D were injected into the hemocoel of S. litura and B. mori with a syringe. The responses of these insects were quite different. In S. litura, both the chemicals inhibited metamorphosis. In B. mori, polyoxin B inhibited the larval molt, whereas polyoxin D had no effect. Body surface treatment with 1% (wt/vol) Polyoxin AL resulted in a failure to molt in both species.

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“…These compounds are structural analogues of UDP-N-acetylglucosamine and have been shown to competitively inhibit fungal chitin synthases (Gooday 1977). The benzoylphenylurea insecticides also inhibit cuticular chitin deposition in a variety of insects (Sowa and Marks 1975;Hajjar and Casida 1978) and appear to act on the final polymerization step of the chitin biosynthetic pathway (Verloop and Ferrell 1977), but it is still unclear whether they directly inhibit chitin synthase. Thus diflubenzuron (one of the benzoylphenylurea insecticides) failed to inhibit chitin synthesis in either of the insect-derived cell-free chitin synthase systems described above (Cohen and Casida 1980b;Mayer et at.…”

Section: Introductionmentioning

confidence: 99%

Integumental Chitin Synthase Activity in Cell-free Extracts of Larvae of the Australian Sheep Blowfly, Lucilia cuprina, and Two Other Species of Diptera

Turnbull¹,

Howells²

1983

Aust. Jnl. Of Bio. Sci.

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Chitin synthase activity has been demonstrated in crude homogenates of larval integuments from L. cuprina and in similar preparations from Musca domestica and Calliphora erythrocephala. This is the first report of an insect integumental chitin synthase. This activity brings about the incorporation of radioactivity from UDP-N-acetyl-[14C]glucosamine into an ethanol-and alkali-insoluble form. A major part of this labelled product has been characterized as chitin by its insolubility in alkali, resistance to degradation by proteases and its susceptibility to digestion by chitinase and RCI. Most of the radioactivity solubilized during digestion by chitinase co-migrates with N-acetylglucosamine, glucosamine and chitobiose during paper chromatography. Some radioactivity also becomes incorporated into non-chitin products in this system. There is substantial evidence that incorporation is not brought about by whole epidermal cells or by microbial contamination in the homogenates. The extent of incorporation obtained with the homogenates is limited by the presence of degradative enzymes which rapidly break down the substrate (UDP-N-acetylglucosamine). The incorporation was partially inhibited (50-70%) by both polyoxin-D (apparent Ki 0'04I1M) and diftubenzuron (apparent . This is the first report of a cell-free chitin-synthesizing system derived from insect tissue which is sensitive to inhibition by diftubenzuron.

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An in vitro system for the quantitative measurement of chitin synthesis in the cockroach: Inhibition by TH 6040 and polyoxin D

Cited by 74 publications

References 7 publications

Effects of Several Larvicidal Compounds on Chitin Biosynthesis by Isolated Larval Integuments of the Sheep Blowfly Lucilia cuprina

Effects of Several Larvicidal Compounds on Chitin Biosynthesis by Isolated Larval Integuments of the Sheep Blowfly Lucilia cuprina

Insecticidal effect of a fungicide containing polyoxin B on the larvae of Bombyx mori (Lepidoptera: Bombycidae), Mamestra brassicae, Mythimna separata, and Spodoptera litura (Lepidoptera: Noctuidae)

Integumental Chitin Synthase Activity in Cell-free Extracts of Larvae of the Australian Sheep Blowfly, Lucilia cuprina, and Two Other Species of Diptera

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