Construction and characterization of two bacterial artificial chromosome libraries of pea (Pisum sativum L.) for the isolation of economically important genes.

Pea (Pisum sativum L.) has a genome of about 4 Gb that appears to share conserved synteny with model legumes having genomes of 0.2-0.4 Gb despite extensive intergenic expansion. Pea plant inventory (PI) accession 269818 has been used to introgress genetic diversity into the cultivated germplasm pool. The aim here was to develop pea bacterial artificial chromosome (BAC) libraries that would enable the isolation of genes involved in plant disease resistance or control of economically important traits. The BAC libraries encompassed about 3.2 haploid genome equivalents consisting of partially HindIII-digested DNA fragments with a mean size of 105 kb that were inserted in 1 of 2 vectors. The low-copy oriT-based T-DNA vector (pCLD04541) library contained 55 680 clones. The single-copy oriS-based vector (pIndigoBAC-5) library contained 65 280 clones. Colony hybridization of a universal chloroplast probe indicated that about 1% of clones in the libraries were of chloroplast origin. The presence of about 0.1% empty vectors was inferred by white/blue colony plate counts. The usefulness of the libraries was tested by 2 replicated methods. First, high-density filters were probed with low copy number sequences. Second, BAC plate-pool DNA was used successfully to PCR amplify 7 of 9 published pea resistance gene analogs (RGAs) and several other low copy number pea sequences. Individual BAC clones encoding specific sequences were identified. Therefore, the HindIII BAC libraries of pea, based on germplasm accession PI 269818, will be useful for the isolation of genes underlying disease resistance and other economically important traits.

Differences in diagnostic approach between family physicians and other specialists in patients with unintentional body weight loss.

BACKGROUND: Unintentional weight loss is a diagnostic dilemma with diverse diagnostic possibilities for physicians. OBJECTIVES: Our study focused on the evaluation of differences in diagnostic approach between family physicians and physicians in other specialties. METHODS: Outpatients who visited National Taiwan University Hospital from January 1996 to December 1996 with unintentional weight loss of 5% or more within 6 months were recruited by a computer search. All data were obtained from a structured medical record audit. RESULTS: There was no significant difference in the utilization of common diagnostic laboratory tests between the two groups. However, other specialists ordered more carcinoembryonic antigen tests (P < 0.01) and hepatitis B antigen tests (P < 0.05), but fewer upper gastrointestinal tract barium studies (P < 0.05) than family physicians. For patients without a definite final diagnosis, the diagnostic total costs for laboratory tests and imaging studies were lower for family physicians than other specialists (P < 0.01). For patients with biomedical disorders, the diagnostic cost was not significantly different between the two groups. For patients with psychological disorders, the costs for imaging studies were lower for family physicians than for other specialists (P < 0.05) but there was no significant difference in the total costs between these two groups. CONCLUSIONS: We conclude that the different approaches between the two groups are due to different training backgrounds and characteristics of practice. The patient-centred concepts of family physicians might be more cost-effective in dealing with undifferentiated problems.