High concentrations of trehalose in aphid hemolymph

Abstract

The major components of hemolymph were examined by 1 H-NMR in seven species of aphids, Acyrthosiphon pisum, Aphis gossypii, Aphis sambuci, Lachnus tropicalis, Megoura crassicauda, Myzus persicae and Uroleucon nigrotuberculatum. Trehalose was detected as the main component from these aphids, and its concentrations in these insects were much higher (196 mM in L. tropicalis to 926 mM in A. gossypii) than those of two other homopterous insects, Cryptotympana facialis (91 mM) and Nephotettix cincticeps (53 mM). Concentrations in L. tropicalis and A. gossypii were equivalent to 1.6% to 2.0% of the fresh weight. Glucose appeared to be an artifact in the hemolymph, because it was not found in the hemolymph when validoxylamine A, a trehalase inhibitor, was added.

High myo-inositol concentration in the hemolymph of planthoppers

“…In a previous paper, we indicated that trehalose is a major component in the hemolymph of homopterous insects; aphid, leafhopper and cicada (Moriwaki et al, 2003). Trehalose synthesized in rice planthoppers may also be utilized as an energy source like in most insects.…”

“…The forelegs of rice planthoppers were pulled out with forceps and the exuding hemolymph collected with a 1 ml microcapillary tube (EM minicaps, Hirschmann ® laborgerate). Hemolymph obtained was immediately diluted with 500 ml heavy water (D 2 O) containing 0.1 ppm validoxylamine A (VAA) and with a small amount of phenylthiourea as previously described (Moriwaki et al, 2003). A total of 2-10 ml of hemolymph was collected from 20 to 100 individuals of each species.…”

“…Very high concentrations of trehalose are found in aphid hemolymph as compared to other insects (Ehrhardt, 1962;Hardie, 1987;Rhodes et al, 1997;Moriwaki et al, 2003). Recently, an unusual trisaccharide, isobemisiose [i.e., a-D-glucopyranosil-(1-6)-a -D-glucopyranosil-(1-1)-a -Dglucopyranose], was reported to occur in the hemolymph of whiteflies, Bemisia argentifolii, Trialeurodes vaporariorum and Aleurodiscus dugesii (Hendrix and Salvucci, 2001).…”

“…However, the regulation of hemolymph sugar levels in homopterous insects is poorly understood because of their small size. We tried to determine the sugar components in the hemolymph of rice planthoppers by 1 H-NMR, a more useful tool for characterizing the components of insect hemolymph as compared to chromatographic methods (Thompson, 1990;Kono et al, 1993Kono et al, , 1995Phalaraksh et al, 1999;Lenz et al, 2001;Moriwaki et al, 2003). As a result, high concentrations of myo-inositol were found in these insects.…”

“…Assignment of the chemical signals on 1 H-NMR and 13 C-NMR spectra was carried out by adding each standard chemical (2 mg) to the sample and checking for overlap of the signals according to Kono et al (1993). The concentrations of the hemolymph components were estimated by calibration curves of standard chemicals (mM) against the ratio of signal strengths of each compound to that of TSP by 1 H-NMR, as previously described (Moriwaki et al, 2003).…”