Sexual-biased gene expression of olfactory-related genes in the antennae of Conogethes pinicolalis (Lepidoptera: Crambidae)

Background Conogethes pinicolalis (Lepidoptera: Crambidae), is similar to Conogethes punctiferalis (yellow peach moth) and its host plant is gymnosperms, especially for masson pine. So far, less literature was reported on this pest. In present study, we sequenced and characterized the antennal transcriptomes of male and female C. pinicolalis for the first time. Results Totally, 26 odorant-binding proteins (OBP) genes, 19 chemosensory proteins (CSP) genes, 55 odorant receptors (OR) genes and 20 ionotropic receptors (IR) genes were identified from the C. pinicolalis antennae transcriptome and most of them were olfactory genes, amino sequences were annotated against homologs of C. punctiferalis. The neighbor-joining tree indicated that the amino acid sequence of olfactory related genes is highly homologous with C. punctiferalis. Furthermore, the reference genes were selected, and we strongly recommended the GAPDH or RP49 to verify gene expression for larvae development and RP49 or RPL13 for adult tissues. Conclusions Our study provides a starting point on the molecular level characterization between C. pinicolalis and C. punctiferalis, which might be a supportive for pest management studies in future.

Biochemical characterization of Serpula lacrymans iron-reductase enzymes in lignocellulose breakdown

Putative iron-reductase (IR) genes from Serpula lacrymans with similarity to the conserved iron-binding domains of cellobiose dehydrogenase (CDH) enzymes have been identified. These genes were cloned and expressed to functionally characterize their activity and role in the decomposition of lignocellulose. The results show that IR1 and IR2 recombinant enzymes have the ability to depolymerize both lignin and cellulose, are capable of the reduction of ferric iron to the ferrous form, and are capable of the degradation of nitrated lignin. Expression of these genes during wheat straw solid-state fermentation was shown to correlate with the release of compounds associated with lignin decomposition. The results suggest that both IR enzymes mediate a non-enzymatic depolymerisation of lignocellulose and highlight the potential of chelator-mediated Fenton systems in the industrial pre-treatment of biomass.

Effect of Epigallocatechin Gallate and Catechin on Overexpression of GSK-3β and IR Genes Induced by Streptozotocin in Rat Brain

Background: Type 2 diabetes mellitus (T2DM) is one of the significant risk factors for Alzheimer disease (AD). Defects in insulin signaling pathway induce AD hallmarks mainly through activation of glycogen synthase kinase-3β (GSK-3β) pathway. Objectives: In this study, we investigated the expression of GSK-3β and insulin receptor (IR) genes in the hippocampi of an animal model of sporadic AD and assessed the preventive effect of Catechin (CAT) and epigallocatechin gallate (EGCG) on their expression. Materials & Methods: Adult male Wistar rats were treated by intracerebroventricular streptozotocin (STZ) injection (3 mg/kg) at day 1 and 3 after cannulation. CAT was administered at a dose of 40 mg/kg for 10 days per gavage, and EGCG was administered at a dose of 3 mg/kg for 14 days into drinking water. Then the animals were decapitated, and their hippocampi were removed. Real-time Polymerase Chain Reaction (PCR) was used to evaluate the alteration in gene expression. Results: There was overexpression in GSK-3β gene in STZ-treated rats (P≤0.05), which was brought back to normalcy by EGCG (P≤0.01). The IR gene also increased after STZ treatment, but CAT reduced IR expression (P≤0.05). However, the suppressive effect of EGCG on IR expression was stronger (P≤0.01). Conclusion: The neuroprotective activity of EGCG might be due to its influence on IR and GSK-3β expression.

Sexual-biased gene expression of olfactory-related genes in the antennae of Conogethes pinicolalis (Lepidoptera: Crambidae)

Background Conogethes pinicolalis (Lepidoptera: Crambidae), is similar to Conogethes punctiferalis (yellow peach moth) and its host plant is gymnosperms, especially for masson pine. So far, less literature was reported on this pest. In present study, we sequenced and characterized the antennal transcriptomes of male and female C. pinicolalis for the first time. Results Totally, 26 odorant-binding proteins (OBP) genes, 19 chemosensory proteins (CSP) genes, 55 odorant receptors (OR) genes and 20 ionotropic receptors (IR) genes were identified from the C. pinicolalis antennae transcriptome and most of them were olfactory genes, amino sequences were annotated against homologs of C. punctiferalis. The neighbor-joining tree indicated that the amino acid sequence of olfactory related genes is highly homologous with C. punctiferalis. Furthermore, the reference genes were selected, and we strongly recommended the GAPDH or RP49 to verify gene expression for larvae development and RP49 or RPL13 for adult tissues. Conclusions Our study provides a starting point on the molecular level characterization between C. pinicolalis and C. punctiferalis, which might be a supportive for pest management studies in future.

Molecular basis of fatty acid taste in Drosophila

Behavioral studies have established that Drosophila appetitive taste responses towards fatty acids are mediated by sweet sensing Gustatory Receptor Neurons (GRNs). Here we show that sweet GRN activation requires the function of the Ionotropic Receptor genes IR25a, IR76b and IR56d. The former two IR genes are expressed in several neurons per sensillum, while IR56d expression is restricted to sweet GRNs. Importantly, loss of appetitive behavioral responses to fatty acids in IR25a and IR76b mutant flies can be completely rescued by expression of respective transgenes in sweet GRNs. Interestingly, appetitive behavioral responses of wild type flies to hexanoic acid reach a plateau at ~1%, but decrease with higher concentration, a property mediated through IR25a/IR76b independent activation of bitter GRNs. With our previous report on sour taste, our studies suggest that IR-based receptors mediate different taste qualities through cell-type specific IR subunits.