Question
How do I answer these?
A. What is the objective or hypothesis of this study?
B. What is the background for doing this experiment?
SUMMARY Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous hemagglutinin (FHA), a surface-displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT-FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro. Exogenous ACT inhibits biofilm formation in a concentration-dependent manner and the N-terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C-terminal segment of FHA with 650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C-terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host-directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT. Graphical Abstract Bordetella FHA MCD Bordetella Biofilm Presence of ACT Reduced Biofilm Bordetella ACT AC Domain Bordetella ABBREVIATED SUMMARY The catalytic domain (AC domain) of Bordetella Adenylate Cyclase Toxin (ACT) interacts witlh the distal tip of Filamentous Hemagglutinin, the mature C-terminal domain with approximately 650 nM affinity. This interaction results in the inhibition of biofilm formation by B. pertussis and B. bronchiseptica in vitro. Despite the AC domain being necessary and sufficient for inhibition, the catalytic activity of ACT is not required for biofilm inhibition
Explanation / Answer
1.Objective of the study
“intraction of N terminus of Adenylated cyclase toxin (AD domin) with C terminus of filamenteous hemagglutinin inhibits biofilm production of Bordetella in vitro“.
2. Background for doing this experiment
Bordetella is a causative agent in wooping cough and emerging health threat. Hence it is necessary to develop inhibition mechanism against this pathogen. This experiment is a step in developing mechanism of inhibition of toxin (ACT). We can develops vaccines by studying the mechanism of action of Bordetella
