The role of haemocytes in the biosynthesis of protocatechuate in the cockroach colleterial system

Whitehead, D. L.

doi:10.1042/bj1190065p

Cited by 10 publications

(4 citation statements)

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“…1). Furthermore, p-hydroxyphenylacetic acid was shown earlier to be derived from (1-14 C) tyramine and (G-3 H) tyramine (Whitehead, 1970a), or in the present case from (2-14 C) tyramine, but not from tritiated octopamine, (middle trace of fig. 6) when the labeled amines were incubated for one hour with haemocytes washed from LCGs with saline (upper trace of fig.…”

Section: Resultssupporting

confidence: 57%

“…The decarboxylase and MAO enzymes were absent in cells of the gland itself when it was washed in insect saline to remove adhering haemocytes. In the absence of the haemocytes, the phenolic glucoside was not synthesized from tyrosine by the isolated gland, (Whitehead, 1970a(Whitehead, , 1974a.…”

Section: Resultsmentioning

confidence: 99%

“…Paper chromatography (using n-Butanol:glacial Acetic acid:water – 4:1:1 (BAW); 2% glacial acetic acid or n-Propanol/N-HCl – 3.1) and high voltage electrophoresis (HVE for 40 min at pH 6.5) was employed to separate the metabolites which formed from L-p-tyrosine as previously described (Whitehead, 1969, 1970a,b). Detection of the metabolites relied on spraying the paper with (i) 0.4% (w/v) ninhydrin in n-butanol saturated water followed by heating for 10 min at 110°C or (ii) equal volumes of 1% (w/v) ferric chloride+1% (w/v) potassium ferricyanide as described (Whitehead et al , 1965).…”

Section: Methodsmentioning

confidence: 99%

“…This article outlines the rô le of certain haemocytes, found to be adhering to the LCG but not to RCG (Whitehead, 1970a), which are responsible for the decarboxylation and deamination of tyrosine, the first two steps in the biosynthetic pathway ( fig. 1) from tyrosine to o-benzoquinones, required for cross-linking oothecins to form sclerotin.…”

Section: Introductionmentioning

confidence: 99%

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Haemocytes play a commensal rôle in the synthesis of the dihydroxybenzoate required as a precursor for sclerotization of the egg case (ootheca) in the cockroachPeriplaneta americana(L)

Whitehead

2010

Bull. Entomol. Res.

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The secretions of the two colleterial glands give rise to the walls of the ootheca which, when hardened, serve to protect fertilised eggs in the cockroach P. americana. The larger left gland (LCG) secretes a β-D-glucoside of 3,4-dihydroxybenzoate, several proteins (oothecins), calcium oxalate crystals and a latent phenoloxidase enzyme. The smaller right gland (RCG) secretes a β-glucosidase. When the two secretions mix in the genital vestibulum, the glucoside is hydrolyzed to glucose and free dihydroxybenzoate, which is then oxidized by the phenoloxidase to the o-benzoquinone, which cross-links the oothecins Scanning and thin section electron microscopy (EM) showed haemocytes adhering to the LCG. The haemocytes were obtained by washing the gland with insect saline; and, when they were incubated with labelled tyrosine, they showed an enhanced ability to decarboxylate L-p-tyrosine to tyramine and then deaminate and oxidize tyramine to give p-hydroxyphenylacetate. After removal of adhering haemocytes, the LCG was no longer able to decarboxylate tyrosine. Injection of α-ecdysone into the abdomens of recently emerged adult females inhibited synthesis of a phenolic glucoside in the developing LCG but not of β-glucosidase produced by RCG. Furthermore, injecting inhibitors of the decarboxylase and monoamineoxidase enzymes partly closed down synthesis in vivo of the phenolic glucoside by LCG. Therefore, in the adult female cockroach, tyramine was converted to p-hydroxyphenylacetate in the haemocytes and then transferred to the gland where it was hydroxylated to 3,4-dihydroxyphenylacetate, which gave rise to a dihydroxybenzoate. Evidence suggested that biosynthesis of the oothecal sclerotizing agent could be controlled by juvenile hormone (JH) acting on the LCG or on haemocytes adhering to the gland.

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Section: Resultssupporting

confidence: 57%

Section: Resultsmentioning

confidence: 99%