Melamine Action in the Phenocopy of Pigment Elimination from Hypodermal Cells of the Silkworm Larva

Tsujita, Mitsuo; Sakurai, Susumu

doi:10.2183/pjab1945.39.513

Cited by 6 publications

(3 citation statements)

References 3 publications

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“…Transparent larvae were prepared by feeding an artificial diet containing 0.05% melamine (Wako Pure Chemical Industries) starting from 0-day-old fifth-instar larvae. Melamine-feeding enhanced the excretion of uric acid and rendered the larval integument transparent as previously reported [28]. The visible effect took place in 2-day-old fifth-instar larvae compared to normally fed larvae.…”

Section: Methodssupporting

confidence: 81%

“…To observe intestinal contraction without opening the larval body, we prepared transparent larvae (Fig 6A (b) ) [28] that exhibited similar inhibitory effects by injection of AT and GSRYa-1 and -2 (Fig 6B) compared to those of normal larvae (Figs 1D and 6A (a) ). In the cephalic and thoracic parts of transparent larvae, two different contractions were observed at the esophagus [24]; a continuous “forward contraction wave” (35–45 waves/min) from the junction between the esophagus and the midgut toward the pharynx (Fig 6C (a) and (b) ), and a strong and intermittent “peristaltic squeeze” (5–6 pulses/min) at the esophagus junction (Fig 6C (a) and (c) ) (S3 Movie).…”

Section: Resultsmentioning

confidence: 99%

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Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

et al. 2019

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Our previous study demonstrated that predominant feeding inhibitory effects were found in the crude extracts of foregut and midgut of the silkworm Bombyx mori larvae. To address the entero-intestinal control crucial for the regulation of insect feeding behavior, the present study identified and functionally characterized feeding inhibitory peptides from the midgut of B . mori larvae. Purification and structural analyses revealed that the predominant inhibitory factors in the crude extracts were allatotropin (AT) and GSRYamide after its C-terminal sequence. In situ hybridization revealed that AT and GSRYamide were expressed in enteroendocrine cells in the posterior and anterior midgut, respectively. Receptor screening using Ca 2+ -imaging technique showed that the B . mori neuropeptide G protein-coupled receptor (BNGR)-A19 and -A22 acted as GSRYamide receptors and BNGR-A5 acted as an additional AT receptor. Expression analyses of these receptors and the results of the peristaltic motion assay indicated that these peptides participated in the regulation of intestinal contraction. Exposure of pharynx and ileum to AT and GSRYamide inhibited spontaneous contraction in ad libitum -fed larvae, while exposure of pharynx to GSRYamide did not inhibit contraction in non-fed larvae, indicating that the feeding state changed their sensitivity to inhibitory peptides. These different responses corresponded to different expression levels of their receptors in the pharynx. In addition, injection of AT and GSRYamide decreased esophageal contraction frequencies in the melamine-treated transparent larvae. These findings strongly suggest that these peptides exert feeding inhibitory effects by modulating intestinal contraction in response to their feeding state transition, eventually causing feeding termination.

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Section: Methodssupporting

confidence: 81%

Section: Resultsmentioning

confidence: 99%

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

et al. 2019

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“…and uric acid occur simultaneously in the pigment granules of the yellow-colored chromatophores of the dorsal integument (Nakagoshi et al, 1992). This situation is reminiscent to that in silkworm larvae, where uric acid occurs together with pteridines in the pigmented granules of the hypodermal cells of the integument (Tsujita and Sakurai, 1964). In both these species, the granules appear as empty spaces under the electron microscope (Nakagoshi et al, 1992), which qualifies them as "reflecting xanthophores" (sensu Tillotson and Oliphant, 1990).…”

Section: Crystalline Pteridines In Invertebratesmentioning

confidence: 93%

Pteridines as Reflecting Pigments and Components of Reflecting Organelles in Vertebrates

Oliphant

Hudon

1993

Pigment Cell Research

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This paper reviews evidence for the presence of pteridines in iridophores, leucophores, and xanthophores in a wide variety of vertebrate chromatophores, and argues that the chemical and functional distinction between pterinosomes and reflecting platelets is not as clear-cut as previously believed. Observations indicate that: (1) Pteridines may, either alone or in conjunction with purines, form pigment granules that reflect light, (2) these pigment granules are highly variable ranging from fibrous pterinosomes to typical reflecting platelets and may be colored, reflect white light, or be iridescent, and (3) many "leucophores" probably contain typical pterinosomes and presumed associated colorless pteridines and are therefore more closely related to erythrophores and xanthophores than to iridophores with which they are usually classified. We propose that the classification of pigment cells should be modified to reflect these facts.

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Rhythmic contractile movements of the larval midgut of the silkworm, Bombyx mori

Hukuhara

Satake

Sato

1981

Journal of Insect Physiology

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Melamine Action in the Phenocopy of Pigment Elimination from Hypodermal Cells of the Silkworm Larva

Cited by 6 publications

References 3 publications

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

Enteroendocrine peptides regulate feeding behavior via controlling intestinal contraction of the silkworm Bombyx mori

Pteridines as Reflecting Pigments and Components of Reflecting Organelles in Vertebrates

Rhythmic contractile movements of the larval midgut of the silkworm, Bombyx mori

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