ABSTRACT
Biofilms are matrix-encapsulated cell aggregates that cause problems in technical and health-related areas; for example, 65 % of all human infections are biofilm associated. This is mainly due to their ameliorated resistance against antimicrobials and immune systems. Pseudomonas aeruginosa, a biofilm-forming organism, is commonly responsible for nosocomial infections. Biofilm development is partly mediated by signal molecules, such as acyl-homoserine lactones (AHLs) in Gram-negative bacteria. We applied horse liver esterase, porcine kidney acylase, and porcine liver esterase; these can hydrolyze AHLs, thereby inhibiting biofilm formation. As biofilm infections are often related to foreign material introduced into the human body, we immobilized the enzymes on medical plastic materials. Biofilm formation was quantified by Crystal Violet staining and confocal laser scanning microscopy, revealing up to 97 % (on silicone), 54 % (on polyvinyl chloride), and 77 % (on polyurethane) reduced biomass after 68 h growth.
Subject(s)
Amidohydrolases/pharmacology , Biofilms/drug effects , Enzymes, Immobilized/pharmacology , Esterases/pharmacology , Plastics , Pseudomonas aeruginosa/growth & development , Animals , Biomass , Horses , Liver/enzymology , Pseudomonas aeruginosa/drug effects , Static Electricity , SwineABSTRACT
A chimeric oxygenase, in which the P450cam domain was fused to the reductase host domains of a P450RhF from Rhodococcus sp. strain NCIMB 9784 was optimised to allow for a biotransformation at 30 mM substrate in 80% overall yield, with the linker region between P450 and FMN domain proving to be important for the effective biotransformation of (+)-camphor to 5-exo-hydroxycamphor.
Subject(s)
Camphor 5-Monooxygenase/chemistry , Camphor 5-Monooxygenase/genetics , Oxidoreductases/chemistry , Oxidoreductases/genetics , Protein Engineering/methods , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Protein Structure, Tertiary , Rhodococcus/enzymology , Transformation, GeneticABSTRACT
Operant conditioning of antennal movements in honey bees was used to investigate whether learned changes on one antenna influence antennal movements of the contralateral antenna. Conditioning of the right antenna did not alter antennal movements of the left antenna and subsequent conditioning of the left antenna did not abolish the previously learned change in the right antenna. Thus, the antennal systems on each side are largely independent from each other.