Anhydrobiosis in nematodes: Control of the synthesis of trehalose during induction

Abstract

Control of the synthesis of trehalose during the induction of anhydrobiosis was examined. Kinetic parameters for TPS did not change during the induction, indicating that there was no de novo synthesis of an isozyme. TPS activity doubled in the presence of a mixture of Na+, K+, Mg++, and Ca++ at concentrations normally found in the worms during induction. The concentration of glucose-6-phosphate increased from about 2 mM in wet worms to about 12 mM at the end of induction, and the concentration of UDPG increased from about 1 mM in wet worms to about 9 mM at the end of induction. The concentration of UDPG was found to be rate limiting. Trehalase activity decreased by half during the induction period. The significance of these data as related to the control of the synthesis of trehalose was discussed.

Enzymatic control of anhydrobiosis‐related accumulation of trehalose in the sleeping chironomid, Polypedilum vanderplanki

“…During the induction of dehydration in an anhydrobiotic nematode, A. avenae , lipid is used as the most likely carbon source to synthesize trehalose via the glyoxylate cycle, and glycogen degradation also contributes to trehalose synthesis [ 39 , 46 ]. In addition, in the trehalose synthesis mechanism of A. avenae during anhydrobiosis induction, it has been reported that the excess substrate influx into TPS is caused by the saturation of glycogen synthase as a result of the increase in UDP-glucose and glucose-6-phosphate as dehydration progresses [ 47 ]. However, as shown in Fig.…”

Cryptobiosis in Tardigrada

“…Using NMR, Clegg ( I 978) has provided strong supportive evidence that these sugars replace bound water and also facilitate its removal by H-bonding. Being a nonreducing sugar, trehalose will not participate in a ' browning reaction between reduced sugars and free amino groups (Crowe & Clegg, 1973) and has been shown to inhibit other browning reactions (Loomis et al, 1980).…”

The level of sugars and synthesis of trehalose inAscaris suumtissues

“…The synthesis of trehalose in nematodes proceeds in the classical pathway and is catalysed by the action of two enzymes: TPS, which catalyses the transfer of glucose from uridine diphosphate (UDP)-glucose to glucose-6-phosphate to produce trehalose-6-phosphate (T6P); and TPP, which can convert T6P to free trehalose and P i (Behm, 1997). The properties of TPS were studied in Aphelenchus avenae (Loomis et al , 1980). Trehalose metabolism genes have also been studied in Caenorhabditis elegans , filarial nematodes (Pellerone et al , 2003) and in A. avenae (Goyal et al , 2005).…”