The observation statistics suggested that the haemolymph melanization speed of larvae became fast and the growth inhibition of Escherichia coli was strong as the quantities of feeding on mulberry leaves increased. The RT-PCR result showed that the mRNA expressions of melanin biosynthesis enzyme BmTan, BmPo-1, BmYellow-f and BmDdc were high in the haemolyph of 5 L 3 d larvae. The qPCR analysis showed Bmtan, Bmddc, Bmyellow, Bmebony and Bmblack, especially Bmddc expression were significantly higher in black disease larvae than in normal larvae. Compared with control, Ddc inhibitors drastically inhibited the lipopolysaccharide-induced haemolymph melanization. In addition, the content of Dopa and Dopamine markedly rose after E. coli injection. These indicated that haemolymph melanization was linked to immune defenses and Bmddc may play a role in melanization response of haemolymph immune in silkworm.
Animals ; Bombyx ; enzymology ; genetics ; microbiology ; Escherichia coli ; Genes, Insect ; Hemolymph ; chemistry ; Larva ; Melanins ; biosynthesis

Carboxylic acids play an important role in both aerobic and anaerobic metabolic pathways of both the snail and the parasite. Monitoring the effects of infection by schistosome on Biomphalaria alexandrina carboxylic acids metabolic profiles represents a promising additional source of information about the state of metabolic system. We separated and quantified pyruvic, fumaric, malic, oxalic, and acetic acids using ion-suppression reversed-phase high performance liquid chromatography (HPLC) to detect correlations between these acids in both hemolymph and digestive gland gonad complex (DGG's) samples in a total of 300 B. alexandrina snails (150 infected and 150 controls) at different stages of infection. The results showed that the majority of metabolite pairs did not show significant correlations. However, some high correlations were found between the studied acids within the control group but not in other groups. More striking was the existence of reversed correlations between the same acids at different stages of infection. Some possible explanations of the underlying mechanisms were discussed. Ultimately, however, further data are required for resolving the responsible regulatory events. These findings highlight the potential of metabolomics as a novel approach for fundamental investigations of host-pathogen interactions as well as disease surveillance and control.
Animals ; Biomphalaria/*chemistry/*parasitology ; Carboxylic Acids/*analysis/metabolism ; Chromatography, High Pressure Liquid ; Gastrointestinal Tract/chemistry ; Hemolymph/chemistry ; Schistosoma mansoni/*chemistry/*growth & development

Three model silkworms, highly resistant strain, highly susceptible strain and their near isogenic line were established by hybridization and backcross. The resistance of silkworm (Bombyx mori L.) to BmNPV was studied at proteomic level using two-dimensional gel electrophoresis and MALDI TOF/TOF MS. Differential expression profiles of proteome in resistant strain, susceptible strain and near isogenic line were obtained, and 180, 190 and 187 of protein spots were shown, respectively. Among them, 80% were concentrated in pI 5-9. Twelve differential protein spots in total were obtained from 3 gels. Using MALDI TOF/TOF MS, five proteins, including aminoacylase, were identified from these spots. The exclusive expression of aminoacylase in highly resistant strain and near isogenic line and its absence in susceptible strain suggest that it might be a BmNPV-resistance related protein.
Amidohydrolases ; analysis ; genetics ; Animals ; Bombyx ; chemistry ; genetics ; virology ; Electrophoresis, Gel, Two-Dimensional ; Hemolymph ; chemistry ; Host-Pathogen Interactions ; genetics ; Insect Proteins ; analysis ; Nucleopolyhedrovirus ; pathogenicity ; physiology ; Proteome ; analysis ; Proteomics ; methods ; Recombination, Genetic ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization