A 44-residue hybrid peptide (CB (1-24)-Arg-Ser-Tyr-Tan (4-21)) incorporating 1-24 residues of cecropin B (CB) and 4-21 residues of thanatin (Tan) was designed and constructed. The CB-Tan gene was cloned into expression plasmid pGEX-3X and expressed in E. coli BL21. The fusion protein was purified by affinity chromatography. After digested with enterokinase the gene product released with antibacterial activity and gave one band in Tricine-SDS-PAGE.
Amino Acid Sequence ; Anti-Bacterial Agents ; metabolism ; Antimicrobial Cationic Peptides ; Base Sequence ; Cloning, Molecular ; Escherichia coli ; genetics ; Insect Proteins ; biosynthesis ; Molecular Sequence Data ; Peptides, Cyclic ; biosynthesis ; Recombinant Fusion Proteins ; biosynthesis ; isolation & purification ; pharmacology

OBJECTIVETo investigate the antibacterial effect of a particular antimicrobial peptide Cecropin B(CB) on Pseudomonas aeruginosa infection of wound in mice.

METHODSThirty ICR mice were enrolled in the study, and the Pseudomonas aeruginosa infection model was reproduced by excision of the full layer of dorsal skin with an area of 1 cm x 1 cm. Then they were randomly divided into C ( control, n = 10, with wet compress of isotonic saline at 3 postinjury hour( PIH) ) , M (with hydropathic compress of 100 g/L mafenide at 3 PIH), A (with wet compress of 1 000 mg/L Cecropin B at 3 PIH) groups. The changes in body temperature and hemogram in each group were determined before and 4 days after injury. Quantitative examination were used to detect the quantity of bacteria in muscular tissue of the wounds, and the survival of the mice were observed on 4 post-injury day( PID).

RESULTSThe wounds were moist with more exudation in C group,while that in other groups were dry without obvious exudation. The body temperature of the majority of the mice in each group were elevated, but the number of leucocytes in each group was lowered after operation. The quantity of bacteria in muscle in A group[ (42 +/- 50) CFU/g] was obviously lower than that in M group [(886+/-804) CFU/g, P <0.05] , and it was all obviously lower than that in C group[ (41 +/-28) x 10(5) CFU/g, P <0.01]. The number of surviving mice after 4 PID in C group was evidently smaller than that in A and M groups( P <0. 05).

CONCLUSIONThe cecropin B possesses obvious anti-bacterial effect on the Pseudomonas Aeruginosa infected wounds of ICR mice, and it can reduce the mortality.

Animals ; Antimicrobial Cationic Peptides ; therapeutic use ; Disease Models, Animal ; Insect Proteins ; therapeutic use ; Male ; Mice ; Mice, Inbred ICR ; Pseudomonas Infections ; drug therapy ; Wound Infection ; drug therapy ; microbiology

Objective To observe the brain cerebrovascular function and blood flow changes in patients with brain diseases during hyperbaric oxygen therapy of different states to provide evidence for their clinical treatment.Methods Forty-nine patients with brain diseases,admitted to our hospital from November 2010 to May 2011,were chosen in our study; their rheoencephalography data captured during a complete hyperbaric oxygen therapy of 4 different states were collected and compared; these 4 states were:state Ⅰ,before pressure raising,which could also be the beginning of the therapy; state Ⅱ,before oxygen intake while pressure coming to a stable level; state Ⅲ,40 min after oxygen uptake; and state Ⅳ,while the pressure inside the chamber coming back to normal level.Results Carotid artery and vertebrobasilar system enjoyed likely changes.Parameters of rheoencephalography showing cerebral blood flow changes,including impedance,raising time,total retraction time and high turn ratio,did not show any differences among the four states (P＞0.05),those showing vascular tension and elasticity,including elasticity index,angle of increasing,top angle of peak value,filling time and amplitude,showed statistically significant difference between each 2 states (P＜0.05),and those showing cerebral vascular resistance,such as resistance index,rising time and high turn ratio,showed significant difference between each 2 states (P＜0.05).Conclusion The hyperbaric oxygen therapy has little effect on changing the brain blood flow; it mainly functions as controlling the impedance and extending the contraction of brain vascular.