The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were...The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.展开更多
Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad an...Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.展开更多
文摘The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.
文摘Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.
