Proteolytic enzyme in the midgut of the pharate adult of the silkworm, Bombyx mori

Eguchi, Masaharu; Furukawa, Shigeru; Iwamoto, Akiko

doi:10.1016/0022-1910(72)90189-8

Cited by 21 publications

(8 citation statements)

References 13 publications

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“…In pharate adults, protease activity increases and reaches another peakjust before emergence. This is in accordance with earlier reports (Eguchi et al 1972) and supports their view that midgut protease in pharate adult might contribute either in part or full towards the formation of cocoonase.…”

Section: Discussionsupporting

confidence: 82%

“…However, most ofthe studies on the midgut protease ofsilkworms are restricted to the larval stage mainly because of its important role in protein digestion. Eventhough Eguchi et al (1972)have studied the proteolytic enzymes in pharate adults, very little information is available on the pattern of change in total protease activity during larval-pupal-adult transformations in silkworms. It has already been reported that the trypsin-like enzyme in mosquitoes changes significantly during metamorphosis (Chen 1978).…”

Section: Introductionmentioning

confidence: 99%

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Alkaline protease in the midgut of the silkwormBombyx mori L: changes during metamorphosis

Sarangi

1985

Proc Ani Sci

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The protease activity in the midgut of bivoltine and multivoltine races of the silkworm, Bombyx mori, was studied. The enzyme activity increased during fifth instar, reached a peak, and decreased significantly through pre-pupal stage to the lowest level at the pupal stage. During pharate adult period, the protease activity increased to reach another peak just before emergence of the moth, and decreased thereafter. The enzyme activity in bivoltines was about 2-3 times higher than multivoltines at the peak levels.Bivoltines showed a sex difference in midgut protease activity while no significant difference was observed in multivoltines.Larvae and pharate adults showed a difference in the pH optima for the enzyme activity. From the results the possible role of midgut protease during the process of metamorphosis is discussed.

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Section: Discussionsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Alkaline protease in the midgut of the silkwormBombyx mori L: changes during metamorphosis

Sarangi

1985

Proc Ani Sci

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“…The digestion of sericin was measured by the method of Eguchi et al, with minor modifications. 14) A mixture of 0.02 mL of sericin solution and 0.04 mL of buffer A was incubated at 30°C in the presence and the absence of 80 U of bmCCN. After a given time, 0.06 mL of 20% trichloroacetic acid (TCA) was added to the mixture, and this was left on ice for 15 min.…”

Section: Purification Of Bmccnmentioning

confidence: 99%

“…6) Studies of CCNs have been done mostly on the ones from the Polyphemus moth (Antheraea polyphemus), [7][8][9][10] the Indian tasar silkworm (A. mylitta), 11) the Chinese Tussah silkmoth (A. pernyi), 12,13) and B. mori. 14-16) Nearly 40 years since extensive studies of CCN in the 1970s, [7][8][9][10][11][12][13][14] few results have been reported except for those focused on B. mori CCN (bmCCN). [15][16][17][18] Recently the recombinant protein of bmCCN was overproduced by means of yeast cells in a technological effort to use it in a more efficient silk-degumming procedure to remove sericin from raw silk.…”

mentioning

confidence: 99%

Purification and characterization of cocoonase from the silkwormBombyx mori

Fukumori

Teshiba

Shigeoka

et al. 2014

Bioscience, Biotechnology, and Biochemistry

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Cocoonase (CCN) which facilitates the degradation of a cocoon is recognized as a trypsin-like serine protease. In this study, CCN from the silkworm Bombyx mori was purified and comprehensively characterized. Its activity was maximal at about pH 9.8. It was stable above pH 3.4 at 4 °C and below 50 °C at pH 7.5. CuSO4, FeSO4, and ZnSO4 showed inhibitory effects on CCN, but other salts improved activity. Typical trypsin inhibitors inhibited CCN, but the relative inhibitory activities were much lower than those against bovine trypsin. An extract of cocoon shells inhibited trypsin, but it was only slightly inhibitory against CCN. There were significant differences in catalytic efficiencies and substrate specificities as between CCN and bovine trypsin.

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“…Digestive serine proteinases have been studied extensively at the biochemical and molecular level. Bombyx mori is the best studied sericigenous Lepidoptera, with an extensive catalogue of detailed research on herbivory and silk production, larval digestive physiology and sequences of digestive enzymes (Legay, 1958; Horie et al ., 1963; Yoshitake, 1967; Eguchi et al ., 1972, 1982; Eguchi & Iwamoto, 1975, 1976, 1982; Horie & Watanabe, 1980; Kageyama et al ., 1981; Sasaki & Suzuki, 1982; Eguchi & Kuriyama, 1983, 1985; Sasaki et al ., 1993; Kurata et al ., 2001; Etebari et al ., 2007). The annotated expressed sequence tag (EST) database for B. mori contains >26 000 sequences including sequence tags from the fifth instar midgut (Mita et al ., 2003).…”

Section: Resultsmentioning

confidence: 99%

Expression of diverse midgut serine proteinases in the sericigenous Lepidoptera Antheraea assamensis (Helfer) is influenced by choice of host plant species

Saikia

Singh

Bhattacharya

et al. 2010

Insect Molecular Biology

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Antheraea assamensis is reared on various species of the Lauraceae family from north-east India for its distinctive cocoon silk. We demonstrate differential expression of digestive trypsin and chymotrypsins in larvae feeding on a primary host, Persea bombycina Kosterm., in comparison to larvae feeding on Litsea monopetala Roxb. using in vitro proteolytic assays, zymogram analyses with proteinase inhibitors, restriction digestion of RNA-PCR amplicons and quantitative real-time PCR (RT-PCR). Eight novel members of the serine proteinase gene family were identified, including an intron-spliced trypsin (AaPb4) and seven putative chymotrypsins (AaPb2, AaPb4, AaPb12, AaLm4, AaLm6, AaLm19 and AaLm29). Midgut transcript levels of the putative trypsin were higher in larvae fed P. bombycina whereas levels of transcripts encoding putative chymotrypsins were higher in larvae reared on L. monopetala. Complex, differential expression of sequence divergent midgut serine proteinases may reflect the ability of lepidopteran larvae to feed on different species of host plants. Possible implications of host plant choice on the digestive physiology of A. assamensis are discussed.

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Proteolytic enzyme in the midgut of the pharate adult of the silkworm, Bombyx mori

Cited by 21 publications

References 13 publications

Alkaline protease in the midgut of the silkwormBombyx mori L: changes during metamorphosis

Alkaline protease in the midgut of the silkwormBombyx mori L: changes during metamorphosis

Purification and characterization of cocoonase from the silkwormBombyx mori

Expression of diverse midgut serine proteinases in the sericigenous Lepidoptera Antheraea assamensis (Helfer) is influenced by choice of host plant species

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