Analysis of the Antimicrobial Activity of Antimicrobial Peptides Extracted from Immunized Tenebrio molitor Induced by Different Microbial Treatments Against 26 Pathogens

[Objective] The study was to explore whether antimicrobial activity of the antimicrobial peptides extracted from immunized Tenebrio molitor varied with different pathogens as inducers.[Method]By inducing T.molitor hungry larvaes to generate immune response via feeding with bacteria and with fungi or actinomycete post to pricking,the antimicrobial peptides extracts were obtained by grinding and centrifuging the cultures.Its antimicrobial activity against 26 pathogens was measured by bacteriostatic ring,and evaluated by trisection to four types and inhibitory spectrum.[Result]Both the antimicrobial activity and antimicrobial spectrum of the antimicrobial peptides extracts varied remarkably among different pathogens as inducers.[Conclusion]Bio-control used strains have obvious advantage in inducing the insect to express body fluid immunity material-antimicrobial peptides.

Isolation and Phylogenetic Analysis of Plant Pathogen-Inhibiting Strains from Southern Ocean

[Objective] The aim was to isolate the strains resistant to plant pathogenic fungi from Southern Ocean and study their phylogenetic relationship and antimicrobial spectrum. [Method] Agar diffusion method was adopted to screen antimicrobial strains and determine the antimicrobial spectrum. Phylogenetic relationship of the strains was analyzed by neighbor-joining method of the Mega 4.0 software. [Result] Twenty antimicrobial strains were screened from seawater of Southern Ocean collected during the 27^th Chinese Antarctic Scientific Expedition. Molecular identification and phyloge- netic analysis indicated that two antimicrobial strains were members of Pseu- domonas, two strains were members of Psychrobacter, and the other 16 trains were members of Pseudoalteromonas. The antimicrobial spectrum of four strains which had higher antimicrobial activity indicated that the strains 312, 83-1 and 195 greatly inhibited the growth of Fusarium oxysporum, Rhizoctonia solani K（Jhn, Phytophthora capsici Leonian, Verticillium dahliae, Alternaria solani, Thanatephoru scucumeris and Phomopsis asparagi （Sacc）; strain 312-1 had obvious antimicrobial effect on the six of the plant pathogens except R. solani. [Conclusion] Four strains which had higher antimicrobial effect were obtained and should be further studied for development and application.

Facile preparation of L-ascorbic acid-stabilized copper-chitosan nanocomposites with high stability and antimicrobial properties

Highly stable dispersions of nanosized copper （Cu） particles with an average size of （2.6 ± 0.5） nm were synthesized by in situ reduction of Cu（II） to immobilize Cu nanoparticles on the amino-enriched surface of chitosan （CTS）. The synthetic process and stability of the L-ascorbic acid-stabilized Cu-CTS nanocomposites were investigated by X-ray photoelectron spectroscopy and Fourier transform Infrared spectroscopy. The antimicrobial efficiency and potency of the Cu-CTS nanocomposites were studied. The Cu-CTS nanocomposites were found to exhibit a broad antimicrobial spectrum and high antimicrobial activity against Gram-positive bacterial pathogen Staphylococcus aureus and fungal pathogen Monilia albican. The minimum inhibitory concentration of the Cu-CTS nanocomposites toward S. aureus was found to be 6.4 μg mL^-1, much lower than those reported in the literature. Furthermore, the Cu-CTS nanocomposites were stable and main- tained good disinfection potential even after 90-day shelf-time under ambient conditions.