Concentration and desalting of peptide and protein samples with a newly developed C18 membrane in a microspin column format.

Protein identification plays an important role in today's academic and industrial proteomic research. Commonly used methods for the separation of proteins from complex samples include liquid chromatography (e.g., ion exchange, reversed-phase, hydrophobic interaction), or types of gel electrophoresis (e.g., 1d and 2d PAGE). Relevant proteins separated in the latter way are often cut out, cleaved with trypsin "in gel," and the resulting peptide mixtures combined with matrix and spotted onto a target plate for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-ms) analysis. Subsequently, proteins can be identified by comparison of the resulting peptide mass fingerprints against different databases.(1) since the success of protein identification can be enhanced by the desalting and concentration of the samples, an innovative C18-membrane was incorporated into a microspin column (Vivapure C18 micro spin column, Vivascience AG, Hannover, Germany) to analyze its performance for sample preparation prior to MALDI-ToF-ms. Rapid concentration of single or multiple 200-microl volumes through an available membrane only 2 mm in diameter allowed for analysis of very dilute samples. We observed the successful and rapid desalting of urea-containing protein samples at 100 fmol/mul up to a mass of approximately 70 KDA and the concentration of digest peptides from a solution of 1 fmol/microl using C18-membrane technology.

Competitive nodulation blocking of cv. Afghanistan pea is related to high levels of nodulation factors made by some strains of Rhizobium leguminosarum bv. viciae.

Cultivar Afghanistan peas are resistant to nodulation by many strains of Rhizobium leguminosarum bv. viciae but are nodulated by strain TOM, which carries the host specificity gene nodX. Some strains that lack nodX can inhibit nodulation of cv. Afghanistan by strain TOM. We present evidence that this "competitive nodulation-blocking" (Cnb) phenotype may result from high levels of Nod factors inhibiting nodulation of cv. Afghanistan peas. The TOM nod gene region (including nodX) is cloned on pIJ1095, and strains (including TOM itself) carrying pIJ1095 nodulate cv. Afghanistan peas very poorly but can nodulate other varieties normally. The presence of pIJ1095, which causes increased levels of Nod factor production, correlates with Cnb. Nodulation of cv. Afghanistan by TOM is also inhibited by a cloned nodD gene that increases nod gene expression and Nod factor production. Nodulation of cv. Afghanistan can be stimulated if nodD on pIJ1095 is mutated, thus severely reducing the level of Nod factor produced. Repression of nod gene expression by nolR eliminates the Cnb phenotype and can stimulate nodulation of cv. Afghanistan. Addition of Nod factors to cv. Afghanistan roots strongly inhibits nodulation. The Cnb+ strains and added Nod factors inhibit infection thread initiation by strain TOM. The sym2A allele determines resistance of cv. Afghanistan to nodulation by strains of R. leguminosarum bv. viciae lacking nodX. We tested whether sym2A is involved in Cnb by using a pea line carrying the sym2A region introgressed from cv. Afghanistan; nodulation in the introgressed line was inhibited by Cnb+ strains. Therefore, the sym2A region has an effect on Cnb, although another locus (or loci) may contribute to the stronger Cnb seen in cv. Afghanistan.

Violent victimization of women and men: physical and psychiatric symptoms.

BACKGROUND: Our objectives for this exploratory study were (1) to assess the prevalence in a family practice of violent victimization of women and men by partners, friends, families, and strangers, and (2) to compare the physical symptoms, depression, alcohol use problems, and social support of women and men who were or were not victimized in the previous 12 months. METHODS: We conducted a cross-sectional, multicenter study of family practice patients (1999-2000). One-thousand twenty-four patients, including 679 women and 345 men from 18 to 64 years of age completed a standard health history and a demographic questionnaire. The health history questionnaire included a question about violent victimization. RESULTS: Violent victimization was reported by 9.9% of the women and 10.9% of the men. Patients who were victimized were grouped into those who were victimized by partners (4.9% of women and 3.0% of men); by friends, or family, or strangers (2.3% of women and 5.0% of men); or by more than one category of persons other than partners (2.6% of women and 3.0% of men). Almost one third of patients victimized by partners were also victimized by another person. Women who were victimized had more physical symptoms than women who were not victimized. Women who were victimized and men who were victimized by their partners had more depressive symptoms than other women and men. Patients who were victimized by more than one category of other victimizers reported more alcohol use problems than other patients. Patients who were victimized reported less social support than patients who were not victimized. CONCLUSIONS: Both women and men report violent victimization in response to a screening question. Violence by partners and by others is related to physical and psychiatric symptoms in women and in men.