Occurrence of poly(hydroxyalkanoate) in the gut homogenate of a phylogenetically higher termite: Macrotermes carbonarius

Gas chromatography analysis of a phylogenetically higher termite-gut homogenate detected the presence of trace amounts of poly(3-hydroxybutyrate) (PHB), a prokaryotic storage material. In addition, the gut homogenate smear, stained with Nile blue A, also suggested the presence of PHB-like granules. Chloroform extracts of both soldier and worker classes of this termite were obtained for further spectroscopic analysis. FTIR, 1H NMR, and 2D 1H-1H NMR analyses confirmed the presence of PHB in both the chloroform extracts. This showed for the first time the occurrence of bacteria capable of accumulating PHB in the termite gut. The results indicated that the physiological environment in the termite gut is suitable for the colonization by PHB-producing bacteria and is probably rich in organic carbon sources, which can be readily assimilated and stored as PHB.Key words: Macrotermes carbonarius, poly(hydroxyalkanoate), PHB, termite

A thiol-activated digestive proteinase from adults of Rhodnius prolixus Stål (Hemiptera: Reduviidae)

Complete activation of proteinase(s) from the digestive midgut of adult Rhodnius prolixus occurs in the presence of thiol activator and EDTA. In the assay procedure developed and reported upon, gut homogenate is added to 1.5 ml 0.1 M potassium phosphate buffer, pH 5.5, containing 1.5 mM dithiothreitol (DTT) and 3 mM EDTA, and is allowed to incubate at 30 °C for 5 min. Fifty microlitres of N-benzoyl- DL-arginine naphthylamine (BANA), 40 mg/ml in dimethyl sulfoxide, is added, and the reaction is stopped after incubation at 30 °C by the addition of 2 ml fast garnet GBC salt colour reagent. Greatest activation occurs with dithiothreitol, followed by cysteine, glutathione, and mercaptoethanol in descending order of activation ability. Complete activation of BANA hydrolysis occurs with 0.4 mM DTT and 1.5 mM EDTA. With the assay, 0.2 gut provides ΔA 520 nm of 0.15 in 30 min. The conditions of the assay suggest that a cathepsin B1-like proteinase is present. The proteinase occurs in the midgut lumen and maximal activity occurs 5–10 days after ingestion of the blood meal.

Influence of Gonads on the Sulfurylation of 11-Deoxycorticosterone and Corticosterone by Rat Liver Cytosol

When incubated in the presence of ATP, the cytosol fraction of rat liver, kidney, and gut homogenate is capable of sulfurylating 11-deoxycorticosterone, the extent of sulfurylation by liver cytosol being three to four times more efficient in the female than in the male. This sex-linked difference in liver sulfokinase activity is further demonstrated by the finding that sulfurylation of corticosterone is decreased by ovariectomy and brought back to the level observed in normal females by injection of 17β-estradiol (at the daily dose of 6 μg/100 g body weight) to castrated females; this effect is increased by orchidectomy and further enhanced by the administration of the same dose of 17β-estradiol to orchidectomized rats.