Mingjiang Kang

Molecular cloning and characterization of a thioredoxin peroxidase gene from Apis cerana cerana.

Thioredoxin peroxidases (Tpxs) play important roles in protecting organisms against the toxicity of reactive oxygen species (ROS) and regulating intracellular signal transduction. In the present study, we cloned the full cDNA of Tpx1 encoding a 195‐amino acid protein from Apis cerana cerana (Acc). Based on the genomic DNA sequence, a 1442‐bp 5′‐flanking region was obtained, and the putative transcription factor binding sites were predicted. Quantitative PCR analysis showed that AccTpx1 was highly expressed in thorax and that the AccTpx1 transcript reached its highest level in two‐week‐old adult worker honeybees. Moreover, expression of the AccTpx1 transcript was increased by various abiotic stresses, such as ultraviolet light, HgCl2, and insecticide treatments. In addition, the recombinant AccTpx1 protein exhibited antioxidant activity; it removed hydrogen peroxide and protected DNA. These results suggest that AccTpx1 plays an important role in protecting honeybees from oxidative injury and may act in extending the lifespan of them.

Identification and characterization of two phospholipid hydroperoxide glutathione peroxidase genes from Apis cerana cerana

Phospholipid hydroperoxide glutathione peroxidase (PHGPX) plays a crucial role in maintaining the integrity of membrane by reducing hydroperoxides of phospholipids. Here, we report the identification and characterization of two genes, designated AccGtpx-1 and AccGtpx-2, encoding PHGPX proteins from the Chinese honeybees, Apis cerana cerana. Alignment analysis showed that AccGtpx-1 and AccGtpx-2 shared high similarity with other known PHGPXs, which show similar structure to thioredoxin. These single copy genes showed complex exon-intron structures. The mRNA of AccGtpx-1 was detected in larvae, pupae and adults and that AccGtpx-2 was only found in adult worker bees. Furthermore, the expression of AccGtpx-1 could be induced by H(2)O(2), ultraviolet (UV) light, heat shock (37 degrees C), HgCl(2), imidacloprid, cyhalothrin, pyriproxyfen and methomyl. In contrast, AccGtpx-2 expression could only be induced by UV. These results indicated for the first time that the AccGtpx-1 and AccGtpx-2 genes encoding A. cerana cerana PHGPXs are regulated differently in response to environmental stressors.

Ribosomal protein L11 is related to brain maturation during the adult phase in Apis cerana cerana (Hymenoptera, Apidae)

Ribosomal proteins (RPs) play pivotal roles in developmental regulation. The loss or mutation of ribosomal protein L11 (RPL11) induces various developmental defects. However, few RPs have been functionally characterized in Apis cerana cerana. In this study, we isolated a single copy gene, AccRPL11, and characterized its connection to brain maturation. AccRPL11 expression was highly concentrated in the adult brain and was significantly induced by abiotic stresses such as pesticides and heavy metals. Immunofluorescence assays demonstrated that AccRPL11 was localized to the medulla, lobula and surrounding tissues of esophagus in the brain. The post-transcriptional knockdown of AccRPL11 gene expression resulted in a severe decrease in adult brain than in other tissues. The expression levels of other brain development-related genes, p38, ERK2, CacyBP and CREB, were also reduced. Immunofluorescence signal attenuation was also observed in AccRPL11-rich regions of the brain in dsAccRPL11-injected honeybees. Taken together, these results suggest that AccRPL11 may be functional in brain maturation in honeybee adults.

Identification and Expression Analysis of a Putative Fatty Acidbinding Protein Gene in the Asian Honeybee, Apis cerana cerana

Abstract Fatty acid-binding proteins (FABPs) play pivotal roles in cellular signaling, gene transcription, and lipid metabolism in vertebrates and invertebrates. In this study, a putative FABP gene, referred to as AccFABP, was isolated from the Asian honeybee, Apis cerana cerana Fabricius (Hymenoptera: Apidae). The full-length cDNA consisted of 725 bp, and encoded a protein of 204 amino acids. Homology and phylogenetic analysis indicated that AccFABP was a member of the FABP multifamily. The genomic structure of this gene, which was common among FABP multifamily members, spanned 1,900 bp, and included four exons and three introns. Gene expression analysis revealed that AccFABP was highly expressed in the dark-pigmented phase of pupal development, with peak expression observed in the fat bodies of the dark-pigmented phase pupae. The AccFABP transcripts in the fat body were upregulated by exposure to dietary fatty acids such as conjugated linoleic acid, docosahexaenoic acid, and arachidonic acid. Transcription factor binding sites for Caudal-Related Homeobox and functional CCAAT/enhancer binding site, which were respectively associated with tissue expression and lipid metabolism, were detected in the 5′ promoter sequence. The evidence provided in the present study suggests that AccFABP may regulate insect growth and development, and lipid metabolism.

Characterization of the cyclin-dependent kinase 6 gene in Apis cerana cerana in response to multiple environmental stresses.

Cyclin-dependent kinases (CDKs) are serine/threonine kinases that play critical roles in the cell cycle regulation. Herein, we describe the identifi cation of a CDK gene from Apis cerana cerana, named AccCDK6. The full-length cDNA is 1,778 bp long, including an ORF of 1,380 bp that encodes a polypeptide of 459 amino acid residues. Multiple sequence alignment analysis showed that the predicted AccCDK6 sequence shares a high similarity with CDK6 genes of other species, and this protein may share an evolutionary predecessor with Drosophila CDK4. The expression patterns of the gene were also analysed, and the transcript was detected throughout the larval, pupal, and adult developmental stages. Furthermore, the expression level of the mRNA of the gene in adult workers was infl uenced by H2O2, ultraviolet (UV) light, temperature (42°C), HgCl2, and pyriproxyfen. These results indicate that AccCDK6 responds to multiple environmental stresses and may also participate in intracellular reactions of reactive oxygen species (ROS) and development processes in honey-bees