Medical licensing board characteristics and physician discipline: an empirical analysis.

This article investigates the relationship between the characteristics of medical licensing boards and the frequency with which boards discipline physicians. Specifically, we take advantage of variation in the structure of medical licensing boards between 1993 and 2003 to determine the effect of organizational and budgetary independence, public oversight, and resource constraints on rates of physician discipline. We find that larger licensing boards, boards with more staff, and boards that are organizationally independent from state government discipline doctors more frequently. Public oversight and political control over board budgets do not appear to influence the extent to which medical licensing boards discipline doctors. These findings are broadly consistent with theories of regulatory behavior that emphasize the importance of bureaucratic autonomy for effective regulatory enforcement.

Correct identification of the chloroplastic protoporphyrinogen IX oxidase N-terminus places the biochemical data in frame.

Maize (Zea mays) protoporphyrinogen IX oxidase (PPO: EC 1.3.3.4) possesses a chloroplast transit peptide (CTP) that delivers the enzyme into the chloroplast. The cleavage site yielding the mature protein was predicted by using the ChloroP software and by comparing conserved regions of the available plant PPO sequences. In parallel, the processed NH(2)-terminus of native PPO was identified experimentally by microsequencing the immunoprecipitated plant PPO from maize etioplasts. The cleavage sites identified using the bioinformatic approaches did not match the experimental result. The three sequences have been cloned and expressed in bacteria and their kinetics were compared in order to understand if the generated proteins had biochemically relevant differences. Recombinant PPO corresponding to the native PPO accumulated at higher level and was more active than the two homologues. A cysteine present in the CTP seems to be able to modify the redox state of the enzyme and to be responsible for the alteration of the kinetic features. In contrast, the sensitivity to different herbicides was unaffected by modifications at the NH(2)-terminus, suggesting that the mode of action is non-competitive and that the NH(2)-terminus is involved in the recognition of the natural substrate.

A high-throughput Arabidopsis reverse genetics system.

A collection of Arabidopsis lines with T-DNA insertions in known sites was generated to increase the efficiency of functional genomics. A high-throughput modified thermal asymmetric interlaced (TAIL)-PCR protocol was developed and used to amplify DNA fragments flanking the T-DNA left borders from approximately 100000 transformed lines. A total of 85108 TAIL-PCR products from 52964 T-DNA lines were sequenced and compared with the Arabidopsis genome to determine the positions of T-DNAs in each line. Predicted T-DNA insertion sites, when mapped, showed a bias against predicted coding sequences. Predicted insertion mutations in genes of interest can be identified using Arabidopsis Gene Index name searches or by BLAST (Basic Local Alignment Search Tool) search. Insertions can be confirmed by simple PCR assays on individual lines. Predicted insertions were confirmed in 257 of 340 lines tested (76%). This resource has been named SAIL (Syngenta Arabidopsis Insertion Library) and is available to the scientific community at www.tmri.org.