BmHSP20.8 is Localized in the Mitochondria and has a Molecular Chaperone Function In Vitro

Biochemical Characterization and Functional Analysis of Glucose Regulated Protein 78 from the Silkworm Bombyx mori

The glucose regulated protein (GRP78) is an important chaperone for various environmental and physiological stimulations. Despite the importance of GRP78 in cell survival and tumor progression, the information regarding GRP78 in silkworm Bombyx mori L. is poorly explored. We previously identified that GRP78 expression was significantly upregulated in the silkworm Nd mutation proteome database. Herein, we characterized the GRP78 protein from silkworm B. mori (hereafter, BmGRP78). The identified BmGRP78 protein encoded a 658 amino acid residues protein with a predicted molecular weight of approximately 73 kDa and comprised of two structural domains, a nucleotide-binding domain (NBD) and a substrate-binding domain (SBD). BmGRP78 was ubiquitously expressed in all examined tissues and developmental stages by quantitative RT-PCR and Western blotting analysis. The purified recombinant BmGRP78 (rBmGRP78) exhibited ATPase activity and could inhibit the aggregating thermolabile model substrates. Heat-induction or Pb/Hg-exposure strongly stimulated the upregulation expression at the translation levels of BmGRP78 in BmN cells, whereas no significant change resulting from BmNPV infection was found. Additionally, heat, Pb, Hg, and BmNPV exposure resulted in the translocation of BmGRP78 into the nucleus. These results lay a foundation for the future identification of the molecular mechanisms related to GRP78 in silkworms.

Transcriptomic analysis reveals Apis mellifera adaptations to high temperature and high humidity

Temperature and humidity are the most important factors affecting the growth, reproduction, and survival of bees. Apis mellifera are important pollinating bees that are widely used in agricultural systems. However, the higher temperatures and humidity in greenhouses are not conducive to the survival of bees. Although previous research has revealed the behavioral responses and physiological mechanisms of honeybees to adapt to high temperature and humidity, there are few data on the exact molecular mechanisms involved. In our study, we investigated gene expression in A. mellifera under different temperature and humidity treatments, using transcriptomic analysis to identify differentially expressed genes (DEGs) and relevant biological processes. Based on the transcriptomic results, we selected several genes with significant differences in expression, and detected the expression patterns of these genes at different temperatures or humidity or different treatment times by q-RT PCR. In the high temperature treatments, 434 DEGs were identified; in the high humidity treatments, 86 DEGs were identified; in the combined high temperature and humidity treatments, 266 DEGs were identified. Analysis results showed that DEGs were enriched in pathways related to amino acid and fatty acid biosynthesis and metabolism under each treatment. In addition, heat shock proteins, zinc finger proteins, serine/threonine-protein kinases, and antioxidase were differentially expressed between the different treatments. The results of the q-RT PCR showed that the expression levels of these genes increased with increasing temperature and over treatment time. Our findings provide a general expression profile of the adaptive expression of heat-resistance genes responding to high temperature and high humidity in A. mellifera, including the expression patterns of several DEGs. Our data provide a basis for future research on the mechanisms underlying the adaptation of insects to high temperature and humidity.

Innate immune responses in the Chinese oak silkworm, Antheraea pernyi

Innate immunity, the evolutionarily conserved defense system, has been extensively analyzed in insect models over recent decades. The significant progress in this area has formed our dominant conceptual framework of the innate immune system, but critical advances in other insects have had a profound impact on our insights into the mystery of innate immunity. In recent years, we focused on the immune responses in Antheraea pernyi, an important commercial silkworm species reared in China. Here, we review the immune responses of A. pernyi based on immune-related gene-encoded proteins that are divided into five categories, namely pattern recognition receptors, hemolymph proteinases and their inhibitors, prophenoloxidase, Toll pathway factors and antimicrobial peptides, and others. Although the summarized information is limited since the research on A. pernyi immunity is in its infancy, we hope to provide evidence for further exploration of innate immune mechanisms.