Hemocyte differentiation in the shore crab (Carcinus maenas) could be accompanied by a loss of glycogenosynthesis capability

Abstract

Hemocytes of the shore crab (C. maenas) were tested for their capability to store glucose, by measurements of the glucose phosphorylating activity. The properties of this hexokinase did not reflect any hepatic role of blood cells for carbohydrate 'storage, since this kinase seemed not to act as a glucose sensor. Moreover, these cells did not release their glycogen in vitro, even in the presence of CHH (crustacean hyperglycemic hormone). These observations led us to reject the hypothesis considering crustacean blood cells as "circulating hepatocytes." A study on separated hemocyte populations for their glycogen content and their ability to synthesize the polysaccharide in vitro provided preliminary results arguing for the connection of the three types of blood cells in a unique cell line. 01993 Wiley-Liss, Inc.

Effect of dietary cornstarch levels on growth performance, enzyme activity and hepatopancreas histology of juvenile red swamp crayfish, Procambarus clarkii (Girard)

“…Once starch is ingested, α-amylase can help using hydrolysis producing glucose in the hepatopancreas, which is liberated slowly into the blood in the form of glucose-6-P and then used as a source of energy in tissues (Loret, 1993;Mc Donald et al, 1989;Santos and Keller, 1993). In the present study, hemolymph glucose levels increased with the increasing cornstarch levels.…”

Usage of energy reserves in crustaceans during starvation: Status and future directions

“…Glycogen is the primary fuel source in exercising crustaceans (Herreid and Full, 1988), and it is mainly stored on the hepatopancreas (Loret, 1993;Gibson and Barker, 1979), while it only represents near 1% of the muscle mass in the estuarine crab Chasmagnathus granulata (Nery et al, 1993). Glycogen has been postulated as the main source for the glucose necessary for chitin synthesis, a major component of crustaceans that may represent up to 35% of the dry weight of shrimp (Omondi and Stark, 1996;Abdel-Rahman et al, 1979).…”

Physiological and biochemical changes of wild and cultivated juvenile pink shrimp Farfantepenaeus duorarum (Crustacea: Penaeidae) during molt cycle

“…This might be associated with captivity and with the unvarying diet of 40% animal protein in experimental conditions. Glycogen reserves are used for exoskeleton formation and their synthesis is essential for shrimp growth (Loret, 1993). Glycogen is converted to glucose; this may be converted to glucosamine and acetylglucosamine, which can then be polymerized to form chitin (Passano, 1960).…”

“…Hemocyanin is an important protein in shrimp; its levels are affected both by the molting process (Bursey and Lane, 1971a;Cheng et al, 2002) and by dietary protein levels . The digestive gland, the hepatopancreas, is an important gland for storage of glycogen (Loret, 1993), which is used in the formation of the exoskeleton . Variations in osmoregulatory capacity and blood glucose concentrations have also been studied in order to detect physiological stress (Charmantier et al, 1989(Charmantier et al, , 1994Mercier et al, 2009;Aparicio-Simon et al, 2010) or the effect of toxic compounds (Lignot et al, 2000), or to relate these variations to molt stages (Galindo et al, 2009).…”