ABSTRACT
Insects exhibit a particular resistance to infections.The activation of the innate immune response of insects is involved in the recognition of the infectious nonself and subsequent activation of cellular and humoral reactions.In humoral reactions,insect antibacterial peptides and lysozyme are very important in resistance to infections.Housefly(Musca domestica) is one of the most important kinds of insects and it has strong ability to adapt to the adverse circumstances.It is of momentous theoretical and practical significance to research the immunity system of housefly.The methods of inducement of housefly larvae were firstly studied.Then an antibacterial protein,whose molecular weight is 28kDa,was purified from housefly larvae,induced by 30% H2O2,through saltout,Sephadex G25 column,Sephadex G75 column and CMSepharose Fast Flow column.This antibacterial peptide had activities against most of Gram positive and Gram negative bacteria.
ABSTRACT
Objective To study the inhibition effects of antibacterial proteins from Musca domestica larvae on JEC and A375 tumour cells. Methods Antibacterial proteins with concentrations of 0.02%,0.1%,0.5%,2.5% and 12.5% were supplied in the culture of JEC and A375 tumour cells in vitro.The cell cycles and apoptosis of JEC and A375 tumour cells were detected by flow cytometry,and the apoptosis index(AI) was measured.The morphology of apoptotic cells was observed with HE stainings and AO staining.The culture without antibacterial proteins was served as control. ResultsThe ratio of apoptosis index/proliferation index(AI/PI) of JEC cells increased with the concentration of antibacterial proteins.The PI and apoptosis rate of 2.5% antibacterial proteins group and 12.5% antibacterial proteins group significantly increased,and G0/G1 significantly decreased.For A375 cells,there were significant differences in G2/M, S,G0/G1,G2/M,AI/PI and PI between 12.5% antibacterial proteins group and control group(P
ABSTRACT
Objective: To research the activity of antibacterial proteins isolated from Musca domestica during larvae-pupae metamorphosis. Methods: The 5-day-old larvae of Musca domestica were injured with a needle. 24h later, the larvae which had changed into pupae were selected. The antibacterial protein was isolated by a four-step protocol including grinding, heating, CM-sepharose F. F. cationexchange chromatography and another CM-sepharose F. F. chromatography. Antibacterial activities of samples were tested by an ultrasensitive radial diffusion assay using Staphylococcus aureus as the indicator organism. The molecular weight of the isolated protein was determined by SDS-PAGE.Results: The molecular weight of this isolated protein was 43kDa, and its antibacterial activity was strong. Conclusions: A kind of protein with strong antibacterial activity can be produced in the Musca domestica during larvae-pupae metamorphosis.
ABSTRACT
Objective: To research the activity of antibacterial proteins isolated from Musca domestica during larvae-pupae metamorphosis. Methods: The 5-day-old larvae of Musca domestica were injured with a needle. 24h later, the larvae which had changed into pupae were selected. The antibacterial protein was isolated by a four-step protocol including grinding, heating, CM-sepharose F. F. cationexchange chromatography and another CM-sepharose F. F. chromatography. Antibacterial activities of samples were tested by an ultrasensitive radial diffusion assay using Staphylococcus aureus as the indicator organism. The molecular weight of the isolated protein was determined by SDS-PAGE.Results: The molecular weight of this isolated protein was 43kDa, and its antibacterial activity was strong. Conclusions: A kind of protein with strong antibacterial activity can be produced in the Musca domestica during larvae-pupae metamorphosis.
ABSTRACT
Objective: To research the activity of antibacterial proteins isolated from Musca domestica during larvae-pupae metamorphosis. Methods: The 5-day-old larvae of Musca domestica were injured with a needle. 24h later, the larvae which had changed into pupae were selected. The antibacterial protein was isolated by a four-step protocol including grinding, heating, CM-sepharose F. F. cationexchange chromatography and another CM-sepharose F. F. chromatography. Antibacterial activities of samples were tested by an ultrasensitive radial diffusion assay using Staphylococcus aureus as the indicator organism. The molecular weight of the isolated protein was determined by SDS-PAGE.Results: The molecular weight of this isolated protein was 43kDa, and its antibacterial activity was strong. Conclusions: A kind of protein with strong antibacterial activity can be produced in the Musca domestica during larvae-pupae metamorphosis.
ABSTRACT
To accelerate the molecular analysis of specifically induced antibacterial peptide against pathogen (E. coli), cDNA library prepared from the larvae fatbody of Bombyx mori was examined by the expressed sequence tag (EST) analysis. In a total of 722 clones, 653 clones were unique genes. Of 653 unique genes, 43.2% (282/653 ESTs) was identified as characterized genes, 38.1% (249/653 ESTs) as uncharacterized genes, and 18.7% (122/653 ESTs) as novel ESTs. According to the functional categorization of the characterized genes, 36.2% (102/282 ESTs) was antibacterial proteins. The highest expressed peptides, 78.4% of all the expressed antibacterial proteins (80/102 ESTs), belonged to the cecropin family. The antibacterial effect of selected clones representing novel ESTs based on a phylogenetic analysis was examined against various bacterial strains. None of the clones showed significant inhibitory effect to the bacteria tested. These results suggested that most of the novel molecules induced by E. coli may not act as immune-induced antibacterial peptides in the fatbody.
Subject(s)
Humans , Bacteria , Bombyx , Clone Cells , Expressed Sequence Tags , Gene Library , Larva , PeptidesABSTRACT
The Acetobacter xylinum and Schizosacchromyces sp. were isolated from tea fungus culture. Each strain 's function on the production of antibacterial protein was explored by single-strain culture and double-strain culture under various condition. The preliminary conclusion is that the protein is synthesized by the yeast cells and its antibacterial activity is significantly improved through modification by bacteria enzymes. The results of co-cultures of several yeasts with the Acetobacter xylinum show that Schizosacchromyces is superior to other yeasts.