Eumelanin is a heteropolymer that is generally composed of hydroxylated indole residues and plays diverse protective functions in various species. Melanin is derived from the amino acid tyrosine and production of melanin is a highly complex oxidative process with a number of steps that can either proceed enzymatically or non-enzymatically. Although melanin plays important protective roles in many species, during melanization, particularly in steps that can proceed non-enzymatically, many toxic intermediates are produced, including semiquinones, dopaquinone, indole-quinones and moreover, the production of many reactive oxygen species. To mitigate the production of reactive species, a number of proteins that regulate the biochemical process of melanization have evolved in various living species, which is closely related to adaptation and physiological requirements. In this communication, we discuss differences between non-enzymatic and enzymatic processes of melanization and the enzymatic regulation of melanization in difference species with an emphasis on differences between mammals and insects. Comparison between melanization and insect sclerotization is also emphasized which raises some interesting questions about the current models of these pathways.
Animals ; Biological Evolution ; Humans ; Insecta ; metabolism ; Mammals ; metabolism ; Melanins ; biosynthesis ; chemistry ; Models, Biological ; Species Specificity

Transmembrane emp24 domain (TMED) gene is closely related to immune response, signal transduction, growth and disease development in mammals. However, only the Drosophila TMED gene has been reported on insects. We identified the TMED family genes of silkworm, Tribolium castaneum, tobacco moth and Italian bee from their genomes, and found that the TMED family gene composition patterns of one α-class, one β-class, one δ-class and several γ-classes arose in the common ancestor of pre-divergent Hymenoptera insects, while the composition of Drosophila TMED family members has evolved in a unique pattern. Insect TMED family γ-class genes have evolved rapidly, diverging into three separate subclasses, TMED6-like, TMED5-like and TMED3-like. The TMED5-like gene was lost in Hymenoptera, duplicated in the ancestors of Lepidoptera and duplicated in Drosophila. Insect TMED protein not only has typical structural characteristics of TMED, but also has obvious signal peptide. There are seven TMED genes in silkworm, distributed in six chromosomes. One of seven is single exon and others are multi-exons. The complete open reading frame (ORF) sequences of seven TMED genes of silkworm were cloned from larval tissues and registered in GenBank database. BmTMED1, BmTMED2 and BmTMED6 were expressed in all stages and tissues of the silkworm, and all genes were expressed in the 4th and 5th instar and silk gland of the silkworm. The present study revealed the composition pattern of TMED family members, their γ class differentiation and their evolutionary history, providing a basis for further studies on TMED genes in silkworm and other insects.
Animals ; Bombyx/metabolism* ; Genes, Insect/genetics* ; Moths/metabolism* ; Insecta/metabolism* ; Drosophila ; Insect Proteins/metabolism* ; Phylogeny ; Mammals/genetics*

Rice stripe virus (RSV) transmitted by the small brown planthopper causes severe rice yield losses in Asian countries. Although viral nuclear entry promotes viral replication in host cells, whether this phenomenon occurs in vector cells remains unknown. Therefore, in this study, we systematically evaluated the presence and roles of RSV in the nuclei of vector insect cells. We observed that the nucleocapsid protein (NP) and viral genomic RNAs were partially transported into vector cell nuclei by utilizing the importin α nuclear transport system. When blocking NP nuclear localization, cytoplasmic RSV accumulation significantly increased. In the vector cell nuclei, NP bound the transcription factor YY1 and affected its positive regulation to FAIM. Subsequently, decreased FAIM expression triggered an antiviral caspase-dependent apoptotic reaction. Our results reveal that viral nuclear entry induces completely different immune effects in vector and host cells, providing new insights into the balance between viral load and the immunity pressure in vector insects.
Animals ; Cell Nucleus ; Hemiptera/metabolism* ; Insect Vectors/genetics* ; Insecta ; Nucleocapsid Proteins/metabolism* ; Oryza ; Plant Diseases ; Tenuivirus/metabolism* ; Virus Replication

OBJECTIVETo establish a method for the expression of glycogen synthase kinase 3β with high purity and biological activity.

METHODSE.coli expression system and baculovirus-insect cell expression system were used to produce the kinase, followed by purification using His-tag and GST-tag and determination of its purity and activity by SDS-PAGE and kinase reaction, respectively.

RESULTSGlycogen synthase kinase 3β produced from E.coli represented 54% of the total bacterial protein, as compared with 96% of the total protein from the insect cell system .Glycogen synthase kinase 3β produced from insect cell exhibited an one-fold higher biological activity than the protein obtained from E.coli.

CONCLUSIONSCompared with the protein from E.coli system, glycogen synthase kinase 3β from the insect cell expression system is endowed with a higher purity and bioactivity.

Animals ; Baculoviridae ; metabolism ; Escherichia coli ; metabolism ; Genetic Vectors ; Glycogen Synthase Kinase 3 ; biosynthesis ; isolation & purification ; Insecta ; cytology

To produce the recombinant baculovirus transfer plasmid pFast-ORF2, the ORF2 gene of Porcine Circovirus type 2 (PCV2) was subcloned into baculovirus transfer vector (pFastBac(TM1) ) using Bac-to-Bac baculovirus expression system. E. coli DH10Bac (Gibco BRL) containing baculovirus shutter vector (bacmid) and helper vector was transformed with recombinant plasmid pFast-ORF2. Within E. coli DH10Bac, the ORF2 gene was transposed into the bacmid. The colonies of E. coli containing recombinant bacmid (Bac. ORF2) were collected by blue/white selection. The Bac. ORF2 was transfected into sf9 cells to yield AcNPV carrying the PCV2 ORF2 gene, referred to as Ac. ORF2. Expression of the ORF2 gene of PCV2 was confirmed by indirect immunofluorescent assay (IIFA), SDS-PAGE and Western-blotting. The expressed ORF2 gene product had a molecular mass of 28kD and could be recognized by the positive serum of PCV2. The results indicated the ORF2 gene was properly expressed in sf9 cell. It was noteworthy that many self-assembled virus-like particles (VLPs) were found in purified and phosphotungstic acid (PTA) stained PCV2 ORF2 protein by electron microscope. The particles were of similar morphology to the PCV2 virion and some self-assembled virus-like particles had darkly stained centers that made them appear to be empty capsids. Both PCV2 particles and self-assembled particles were approximately 17 nm in diameter.
Animals ; Baculoviridae ; genetics ; metabolism ; Circovirus ; genetics ; metabolism ; Escherichia coli ; genetics ; metabolism ; Insecta ; cytology ; metabolism ; Open Reading Frames ; genetics ; Recombinant Proteins ; genetics ; metabolism ; Swine ; Viral Proteins ; genetics ; metabolism ; Virion

Baculoviruses are a family of arthropod-specific viruses that produce two morphologically distinct types of virions (budded and occlusion-derived) in their lifecycle. Baculoviruses establish infection in the midgut of their host via the oral route: occlusion-derived virions have pivotal roles in these processes. This review summarizes the basic characteristics of baculoviruses, and discusses the composition and classification of baculovirus occlusion-derived virions. The latter focuses mainly on the evolution and role of multiple occlusion-derived virions in the lifecycle of baculoviruses. These achievements should aid understanding the evolution and infection mechanisms of baculoviruses.
Animals ; Baculoviridae ; genetics ; growth & development ; physiology ; Insecta ; virology ; Viral Proteins ; genetics ; metabolism ; Virion ; genetics ; growth & development ; physiology

Bacillus thuringiensis is widely used as an insecticide which is safe and environmentally friendly to humans and animals. One of the important insecticidal mechanisms is the binding of Bt toxins to specific toxin receptors in insect midgut and forming a toxin perforation which eventually leads to insect death. The resistance of target pests to Bt toxins is an important factor hampering the long-term effective cultivation of Bt crops and the continuous use of Bt toxins. This review summarizes the mechanism of insect resistance to Bt toxins from the perspective of important Bt toxin receptors in midgut cells of Lepidopteran insects, which may facilitate the in-depth study of Bt resistance mechanism and pest control.
Animals ; Bacillus thuringiensis/genetics* ; Bacillus thuringiensis Toxins ; Bacterial Proteins/metabolism* ; Endotoxins/metabolism* ; Hemolysin Proteins/metabolism* ; Insecta/metabolism* ; Insecticide Resistance/genetics* ; Insecticides/pharmacology* ; Pest Control, Biological

As one of the most important aquatic fish, Micropterus salmoides suffers lethal and epidemic disease caused by rhabdovirus at the juvenile stage. In this study, a new strain of M. salmoides rhabdovirus (MSRV) was isolated from Yuhang, Zhejiang Province, China, and named MSRV-YH01. The virus infected the grass carp ovary (GCO) cell line and displayed virion particles with atypical bullet shape, 300-500 nm in length and 100-200 nm in diameter under transmission electron microscopy. The complete genome sequence of this isolate was determined to include 11 526 nucleotides and to encode five classical structural proteins. The construction of the phylogenetic tree indicated that this new isolate is clustered into the Vesiculovirus genus and most closely related to the Siniperca chuatsi rhabdovirus. To explore the potential for a vaccine against MSRV, a glycoprotein (1-458 amino acid residues) of MSRV-YH01 was successfully amplified and cloned into the plasmid pFastBac1. The high-purity recombinant bacmid-glycoprotein was obtained from DH10Bac through screening and identification. Based on polymerase chain reaction (PCR), western blot, and immunofluorescence assay, recombinant virus, including the MSRV-YH01 glycoprotein gene, was produced by transfection of SF9 cells using the pFastBac1-gE2, and then repeatedly amplified to express the glycoprotein protein. We anticipate that this recombinant bacmid system could be used to challenge the silkworm and develop a corresponding oral vaccine for fish.
Animals ; Baculoviridae/metabolism* ; Bass/metabolism* ; Carps/virology* ; Cell Line ; Female ; Genetic Techniques ; Genome, Viral ; Glycoproteins/biosynthesis* ; Insecta ; Ovary/virology* ; Phylogeny ; Plasmids/metabolism* ; Recombinant Proteins/biosynthesis* ; Rhabdoviridae/metabolism*

Antimicrobial peptides (AMPs), a class of short proteins with a broad spectrum of antibacterial activities, are isolated from a wide variety of animals, both vertebrates and invertebrates, and plants as well as from bacteria and fungi. They are a key component of the innate immune response in most multicellular organisms. Owing to their potent, broad-spectrum antibacterial activities and uneasy developing of drug resistance, these peptides are of great clinical significance. However, preparation of AMPs at a large scale is a severe challenge to the development of the commercial products. Undoubtedly, construction of high-level biological expression systems for the production of AMPs is the key in its clinical application process. Herein, we summarize the progress in researches on heterogenous expression of AMPs in prokaryotic expression systems and eukaryotic expression systems.
Animals ; Antimicrobial Cationic Peptides ; biosynthesis ; chemistry ; genetics ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Insecta ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; Yeasts ; genetics ; metabolism

Eukaryotic membrane proteins, many of which are key players in various biological processes, constitute more than half of the drug targets and represent important candidates for structural studies. In contrast to their physiological significance, only very limited number of eukaryotic membrane protein structures have been obtained due to the technical challenges in the generation of recombinant proteins. In this review, we examine the major recombinant expression systems for eukaryotic membrane proteins and compare their relative advantages and disadvantages. We also attempted to summarize the recent technical strategies in the advancement of eukaryotic membrane protein purification and crystallization.
Animals ; Escherichia coli ; genetics ; Eukaryotic Cells ; metabolism ; Genetic Vectors ; HEK293 Cells ; Humans ; Insecta ; cytology ; genetics ; Membrane Proteins ; chemistry ; genetics ; metabolism ; Recombinant Proteins ; chemistry ; metabolism ; Yeasts ; genetics