Developmental changes in urea in the haemolymph (determined by a urease-indophenol method) in hybrid strains of the silkworm, Bombyx mori and the effect of starvation in the fifth instar larvae, fed an artificial diet, on urea level in subsequent development

Biochemical changes in hemolymph of spinning and non-spinning silkworm larvae, Bombyx mori (L., 1758) (Lepidoptera: Bombycidae), reared on fresh mulberry leaves: possible reasons for non-spinning syndrome

“…It has been shown that hemolymph of silkworm larvae reared on mulberry leaves contains a considerable quantity of urea (Yamada et al, 1983;Sumida et al, 1990). Urea concentration in the hemolymph increases until days 4 and 5 of the fifth instar, but then decreases sharply to day 7, probably as a result of the sufficient sequestration of urease derived from the ingested mulberry leaves (Sumida et al, 1993). Consistent with these findings, we determined that urea concentrations in spinning larvae hemolymph decreased significantly between days 5 and 7 of the fifth instar.…”

Characterization of entomopathogenic nematodes and symbiotic bacteria active against Spodoptera frugiperda (Lepidoptera: Noctuidae) and contribution of bacterial urease to the insecticidal effect

“…Although most insects are uricotelic, urea has been detected in the hemolymph and in the excreta of many insects and arginase is widely distributed in insects (Burrsell, 1967;Cochran, 1985;Klowden, 2007;Pant and Kumar, 1978). It is noteworthy that in some insects urea concentration in the hemolymph increases depending on the diet and under certain physiological conditions, such as metamorphosis (Hirayama et al, 1999;Pant and Kumar, 1978;Sumida et al, 1993). An increased amount of urea in the infected S. frugiperda may result from the release of mitochondrial arginase and arginine from injured tissues.…”

Assessing the Potential of Adenosine and L-Theanine as Metabolic Suppressants for Improving Shipping of the New Zealand Scampi (Metanephrops challengeri)

“…Ammonia and Urea. Haemolymph ammonia and urea were quantified using a modified berthelot/indophenol blue method outlined in Pozhoth and Jeffs's [38] and Sumida et al's [43] studies. The indophenol blue method is a colorimetric assay that consists of reacting ammonia with hypochlorite to form monochloramine, this is then reacted with phenol to produce a blue indophenol compound that is then quantified at 625 nm.…”