SEQUENCING AND CHARACTERIZATION OF GLYCOGEN SYNTHASE AND GLYCOGEN PHOSPHORYLASE GENES FROM Spodoptera exigua AND ANALYSIS OF THEIR FUNCTION IN STARVATION AND EXCESSIVE SUGAR INTAKE

Abstract

Glycogen and trehalose are important energy source and key regulation factors in the development of many organisms' pass through energy metabolism, including bacteria, fungi, and insects. To study glycogen metabolism pathway in Spodoptera exigua, first cDNAs for glycogen synthase (SpoexGS) and glycogen phosphorylase (SpoexGP) were cloned from S. exigua. SpoexGS cDNA contains an open reading frame of 2,010 nucleotides encoding a protein of 669 amino acids with a predicted molecular mass of 76.19 kDa and a pI of 5.84. SpoexGP contains an open reading frame of 2,946 nucleotides, which encodes a protein of 841 amino acids with a predicted molecular mass of approximately 96.63 kDa and a pI of 6.03. Second, Northern blotting revealed that SpoexGS and SpoexGP mRNAs were expressed in brain, fat body, mid-gut, Malpighian tubules, spermary, and tracheae of S. exigua. Expression patterns for SpoexGS and SpoexGP mRNAs were similar in fat body, but differed in whole body at different developmental stages. The last, under starvation conditions, SpoexGS and SpoexGP transcript expression rapidly decreased with increasing starvation time. When the starvation stress was removed, SpoexGS and SpoexGP mRNA levels were lower in the groups starved for 6 and 12 h than in the 24-h starvation and control groups. Treatment with excessive sugar intake led to higher levels of SpoexGS and SpoexGP transcripts after 12 h compared to the control group. These findings provide new data on the tissue distribution, expression patterns, and potential function of glycogen synthase and glycogen phosphorylase proteins.

Regulation of hemolymph trehalose level by an insulin-like peptide through diel feeding rhythm of the beet armyworm, Spodoptera exigua

“…Glycogen phosphorylase (GP) and TPS for trehalose biosynthesis and trehalase for trehalose breakdown to monomer glucose are cloned and assessed in molecular levels [51][52][53]. Starvation significantly reduced expression of GP, which would result in shutdown of trehalose synthesis [53]. This suggests that the increase of trehalose in response to starvation in this current study may be resulted from the storage of trehalose in the cells and release into hemolymph through the activated trehalose transporter.…”

“…In S. exigua, most genes related with trehalose metabolism have been identified. Glycogen phosphorylase (GP) and TPS for trehalose biosynthesis and trehalase for trehalose breakdown to monomer glucose are cloned and assessed in molecular levels [51][52][53]. Starvation significantly reduced expression of GP, which would result in shutdown of trehalose synthesis [53].…”

Knockdown of five trehalase genes using RNA interference regulates the gene expression of the chitin biosynthesis pathway in Tribolium castaneum

“…Glycogen phosphorylase (GP) in the decomposition pathway together with glycogen synthase (GS) in the synthetic pathway regulates glycogen levels. Glucose-6-phosphate generated through the hydrolysis of trehalose and degradation of glycogen is transformed into fructose-6-phosphate by glucose-6-phosphate isomerase (GPI), which plays different roles in the chitin biosynthesis pathway after the enzymatic action of glutamine: fructose-6-phosphate transaminase (GFAT) and in the glycolysis pathway after the enzymolysis of phosphofructokinase (PFK) (Additional file 1: Figure S1) [16–20]. …”

URSOLIC ACID AND CIS-TILIROSIDE PRODUCED BY Merremia tomentosa AFFECT OVIPOSITION OF Leucoptera coffeella ON COFFEE PLANTS

“…60 A pharmacophoric search employing ursolate (deprotonated state of ursolic acid) resulted in the selection of glycogen phosphorylases (Tanimoto score 10 = 0.68), which catalyze the hydrolysis of glycogen to glucose-1-phosphate and appear to play essential roles in insect energy homeostasis. 29,61 Unfortunately, no information about the production of these enzymes could be found for L. coffeella. Actually, no three-dimensional structure for glycogen phosphorylases from insects could be found in the literature.…”

“…28 Their amino acid sequences, as well as that of a glycogen phosphorylase from Spodoptera exigua (Hübner, 1808) (Lepidoptera: Noctuidae) (accession number FJ754277.1 in GenBank: http://www.ncbi.nlm.nih.gov/ nuccore/FJ754277), 29 were aligned using the software Ugene 1.11.5 30 and the ClustalW 2.1 algorithm 31 with the default parameters. Then, the amino acid sequences of 1F6D, 1IOV, 1L6I, 1YGP, 1Z8D, 2ATI, 2C4M, 2QLL, 2QN1, 2ZB2, 3CEH, 3DD1, 3SOJ, 4EJ2 and FJ754277.1, were employed in a search for similar amino acid sequences of insects in the nonredundant (nr) database of the NCBI Portal (http://blast.ncbi.nlm.…”