Comparative analysis on the expression of inducible HSPs in the silkworm, Bombyx mori.

Heat shock proteins (HSPs), well-known in respond to various kinds of stress situations, have been widely studied in Drosophila. However, a few reports related to silkworm bombyx mori. Genetic and non-genetic factors affecting on the expression of some HSPs in heat-treated silkworm were studied at the present paper. The mRNA levels of HSPs were quantified by real-time quantitative RT-PCR method and compared with their expression in the proteome profiles. The results showed up-regulation of two small heat shock proteins (sHSPs), HSP19.9 and HSP20.4 and down-regulation of HSP70 in the fat body, testis and ovary of heat exposed larvae. Higher variation of the sHSPs than HSP70 was observed in the different conditions such as heat exposures and genetic backgrounds. Significant difference in the HSP19.9 expression between two breeds was observed which implied the importance of this gene in the genetic differences. There was significant difference between responses of severe and mild heat shocks after 4 h heat recovery. The HSPs expression in male was significantly higher than that in female silkworm larva for all transcript measurements (P < 0.001). Comparison of two methods of quantification showed a fair similarity between HSPs expression in the transcriptome and proteome levels. Nistari breed as a naturally thermo-tolerant breed was expressed lower HSPs than a thermo-sensitive breed.

Shotgun proteomic analysis on the embryos of silkworm Bombyx mori at the end of organogenesis.

Embryonic development of silkworm, Bombyx mori is a process of systematical expression of genes and proteins which is dominated by complex regulatory networks. To gain comprehensive insight into the molecular basis of embryonic development and its regulation mechanisms, the proteome profile of the B. mori embryos at the end of organogenesis (tubercle appearance stage, TA) was characterized using LTQ-Orbitrap mass spectrometer. Totally 963 proteins were identified with a false discovery rate (FDR) of 0.12%. They were involved in embryonic development, chemoreception, and stimuli response and so forth. The proteins with the largest number of identified unique peptides, implying their possibly higher abundance, were involved in heat shock response, lipid transport and metabolism, and apoptosis. It was consistent with the physiological status of embryo at the end of organogenesis. Many functionally important proteins were identified for the first time in B. mori embryo such as the progesterone receptor membrane component 2, antennal binding protein, sericotropin, and molting fluid carboxypeptidase A (MF-CPA). 253 (26.27%) specific proteins in TA versus labrum appearance stage (LA, four days before TA) embryos were identified, which were mainly associated with musculature, nervous system, and chemoreception system. They disclosed the differential temporal and spatial expression of proteins in the process of organogenesis. The relative mRNA levels of fifteen identified proteins in the two experimented stages were also compared using quantitative reverse transcription PCR (qRT-PCR) and showed some inconsistencies with protein expression. Gene Ontology (GO) annotation of the identified proteins showed that the most proteome representations were in the categories of "binding" and "catalytic" in molecular function, and "cellular process" and "metabolic process" in biological process.

Proteomic and bioinformatic analysis on endocrine organs of domesticated silkworm, Bombyx mori L. for a comprehensive understanding of their roles and relations.

Three organs of silkworm larva endocrine system, including brain (Br), subesophageal ganglion (SG) and prothoracic glands (PG), were studied employing shotgun LC-MS/MS combined with bioinformatic analysis to comprehensively understand their roles and relations. Totally, 3430, 2683, and 3395 proteins were identified including 1885 common and 652, 253, and 790 organ-specific ones in Br, SG, and PG, respectively. Identified common-expressed proteins indicated the existence of intrinsic complex interactions among these parts of endocrine system. Most of the reputed organs-specific proteins were identified by this approach. KEGG pathway analysis showed 162 same pathways among the 169, 164, and 171 relating Br, SG, and PG. This analysis revealed functional similarities with exceptional resemblance in their metabolism and signaling pathways of the three organs. On the other hand, 70, 57, and 114 organ-specific enzymes related pathways were detected for Br, SG, and PG confirming their functional differences. These results reveal a cooperative mechanism among the three endocrine organs in regulating various physiological and developmental events, and also suggest that the organ-specific proteins might be the fundamental factors responsible for the functional differentiation of these organs.