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Biomedical subjects

A Isogai

Publications and source records attributed to A Isogai.

At least 91 records · Page 5Linked to original sources
PubMed1987

A monoclonal antibody against a synthetic fragment of bombyxin (4K-prothoracicotropic hormone) from the silkmoth, Bombyx mori: characterization and immunohistochemistry.

Monoclonal antibodies were produced by immunizing mice with a synthetic decapeptide corresponding to the N-terminal portion of the A-chain of bombyxin, a peptide from Bombyx mori which activates the prothoracic glands of the saturniid moth, Samia cynthia ricini, and was previously called 4K-PTTH. We obtained a hybridoma clone secreting an antibody that recognized specifically bombyxin after treatments for disulfide-bond reduction but did not when untreated. Immunoblotting studies demonstrated the presence of highly heterogeneous immunoreactive components in Bombyx brain homogenates. Immunohistochemistry using this antibody indicated that bombyxin was produced by four pairs of mid-dorsal neurosecretory cells of the brain and transferred to and released from the corpora allata of Bombyx.

Animals↗
PubMed1986

Isolation and structure of the Streptococcus faecalis sex pheromone, cAM373.

The Streptococcus faecalis sex pheromone, cAM373, which induces a mating response of donor cells harboring plasmid pAM373 and is also produced by Staphylococcus aureus, was isolated and its structure determined. Supernatant from an overnight culture of a recipient strain was subjected to successive purification procedures, and 4.4 micrograms cAM373 was obtained. The isolated pheromone showed activity at a concentration as low as 5 X 10(-11) M. Sequence analysis indicated that cAM373 was a heptapeptide, H-Ala-Ile-Phe-Ile-Leu-Ala-Ser-OH, and that its Mr was 733. A synthetic replicate of the peptide showed the same biological activity and chromatographic behavior as the native cAM373.

Amino Acid Sequence↗
PubMed1986

Amino acid sequence of a prothoracicotropic hormone of the silkworm Bombyx mori.

We have determined the complete amino acid sequence of 4K-PTTH-II, one of three forms of the M(r) 4400 prothoracicotropic hormone of the silkworm Bombyx mori, active to brainless pupae of Samia cynthia ricini. Like vertebrate insulin, it consists of two nonidentical peptide chains (A and B chains). The A chain consists of 20 amino acid residues. The B chain is a mixture of four microheterogeneous peptides, two of which consist of 28 residues, and the other two, of 26 residues. 4K-PTTH-II has considerable sequence homology (40%) with human insulin, and it resembles porcine relaxin both in the carboxyl-terminal cysteine residue of the A chain and in the amino-terminal pyroglutamic acid residue of the B chain. The identical distribution of the six cysteine residues also indicates that 4K-PTTH-II belongs to the insulin family.

Journal Article↗
PubMed1985

N-terminal amino acid sequence of an insect neurohormone, melanization and reddish coloration hormone (MRCH): heterogeneity and sequence homology with human insulin-like growth factor II.

An insect neurohormone, melanization and reddish coloration hormone (MRCH), is responsible for cuticular melanization and epidermal red pigmentation in the armyworm. The three molecular forms of MRCH were isolated from adult heads of the silkworm, Bombyx mori, and their N-terminal amino acid sequences revealed a sequence homology with the C-terminal region of human insulin-like growth factor-II as well as N-terminal heterogeneity of MRCHs.

Amino Acid Sequence↗
PubMed1985

Structure of alahopcin (nourseimycin), a new dipeptide antibiotic.

The structure of alahopcin (nourseimycin) (1), a new dipeptide antibiotic isolated from Streptomyces, has been established to be (2S, 3R)-2-[(L-alanyl)amino]-4-formyl-3-(hydroxy-aminocarbonyl)butyric acid. 1 exists in two cyclic hemiacetal type tautomers formed by intramolecular ring closure between the hydroxyamino group and the formyl group in aqueous solution. The structure of the new weakly acidic amino acid (2), a constituent of 1, is revealed to be (2S, 3R)-2-amino-4-formyl-3-(hydroxyaminocarbonyl)butyric acid, and 2 also exists in two cyclic hemiacetal type tautomers in aqueous solution.

Anti-Bacterial Agents↗
PubMed1984

Isolation and structure of the bacterial sex pheromone, cAD1, that induces plasmid transfer in Streptococcus faecalis.

The Streptococcus faecalis sex pheromone cAD1, which is involved in the conjugative transfer of the hemolysin plasmid pAD1, has been isolated and its structure determined. Its Mr is 818 and its amino acid sequence is H-Leu-Phe-Ser-Leu-Val-Leu-Ala-Gly-OH. A replicate of the pheromone synthesized by the liquid-phase method showed the same biological activity and chromatographic behavior as the isolated cAD1. Pheromone activity was detectable at a concentration of approximately 5 X 10(-11) M.

Amino Acid Sequence↗
PubMed1984

Isolation and structure of bacterial sex pheromone, cPD1.

The Streptococcus faecalis sex pheromone cPD1, which induces a mating response in cells harboring the conjugative plasmid pPD1, has been isolated and its structure determined. It was found to have a molecular weight of 912, and its amino acid sequence was H-Phe-Leu-Val-Met-Phe-Leu-Ser-Gly-OH. A synthetic octapeptide showed the same biological activity and chromatographic behavior as the isolated cPD1. Pheromone activity was detectable at a concentration of approximately 4 X 10(-11)M.

Amino Acid Sequence↗
PubMed1984

Isolation and some characterization of the prothoracicotropic hormone from Bombyx mori.

The prothoracicotropic hormone (PTTH) was isolated from adult heads of Bombyx mori. Fifty micrograms of pure PTTH was obtained from 648,000 heads through a 15-step purification procedure with a 2 X 10(6)-fold purification and an 8% recovery. Chemical analyses of this PTTH have shown that it is a single-chain peptide consisting of 40-43 amino acid residues (MW, 4330-4740), the N-terminus of which is glycine. As little as 0.1 ng of PTTH elicited adult development in a debrained pupa of Samia cynthia ricini. Five picograms of PTTH directly stimulated the prothoracic glands in vitro so as to enhance ecdysone release. The hemolymph ecdysteroids of brainless Samia pupae that were developed by PTTH injection increased with essentially the same pattern as in developing normal pupae.

Amino Acid Sequence↗
PubMed1982

Inhibitory effect of bassianolide, a cyclodepsipeptide, on drug-induced contractions of isolated smooth muscle preparations.

Bassianolide (BASS) is a cyclodepsipeptide isolated from cultured mycelia of Beauveria bassiana and is pathogenic to insects. In a longitudinal muscle preparation from guinea pig ileum, 10(-6) M BASS almost irreversibly inhibited an isotonic contraction induced by acetylcholine (ACH) and made the dose-response curve shift in parallel to the right (pA2: 7.6). It also inhibited the contractions induced by carbachol, pilocarpine, histamine, 5-hydroxytriptamine (5-HT) and prostaglandin E2, but did not inhibit the contraction induced by barium or a high concentration (40-60 mM) of potassium (high K). When applied to the guinea pig vas deferens, 10(-8) - 10(-7) M BASS inhibited an isometric contraction induced by norepinephrine (NE) (3 x 10(-6) - 10(-5) M), phenylephrine (3 x 10(-6) - 10(-5) M) or ACH (10(-6) - 10(-5) M). When the contractions of the three agonists exceeded the concentrations mentioned above, BASS failed to exert an inhibitory effect upon any of these agonists. It also inhibited the contraction caused by carbachol and histamine, but did not inhibit that induced by barium or high K. BASS itself failed to cause the contraction or relaxation of both muscle preparations. From these results, it is suggested that BASS inhibits the contraction induced by an agonist which acts upon selective sites of smooth muscle cells, but which does not inhibit a contraction induced by an agonist that has an effect on non-selective sites of cells.

Acetylcholine↗
PubMed1980

Large-scale purification of prothoracicotropic hormone of the silkworm (Bombyx mori).

Prothoracicotropic hormone has been successfully extracted from as many as 2,800,000 silkworm male adult heads and purified partially through an 8-step procedure. Approximately 7 microgram of the crude preparation ("crude PTTH") shows activity in the debrained Samia pupa test. A further 4-step chromatographic purification of the "crude PTTH" derived from 100,000 Bombyx heads yields 3.4 mg of purified preparation ("highly purified PTTH"), of which 7 ng causes adult development in a debrained Samia pupa.

Animals↗
PubMedDate not supplied

Synthesis of bombyxin-IV, an insulin-like heterodimeric peptide from the silkworm, Bombyx mori.

Bombyxin-IV, a molecular species of bombyxin, which is a member of insulin-like heterodimeric peptides of the silkworm Bombyx mori with prothoracicotropic hormone activity, was synthesized. The A- and B-chains of bombyxin-IV containing four and two Cys residues, respectively, were first synthesized separately by solid phase chemistry using Boc protocol. Then they were coupled by stepwise removal of two different protecting groups at the cysteinyl thiols for semiselective formation of disulfide bridges to give bombyxin-IV in 8% yield. The synthetic bombyxin-IV was shown to have chromatographic and biological properties identical with those of natural bombyxin-IV.

Amino Acid Sequence↗