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Abstract

A rapid and economical method for hybrid purity testing of tomato (Lycopersicon esculentum L.) F 1 hybrids using ultrathin-layer isoelectric focusing of alcohol dehydrogenase variants from seedsIn the cultivated tomato (Lycopersicon esculenturn L.), two electrophoretic variants of the enzyme alcohol dehydrogenase (ADH) encoded by the alleles Adh-I and Adh-1' are found. A rapid and economic method for testing the hybrid purity of tomato F 1 seeds, based on the expected presence of Adh-1 alleles, was developed. The method is based on the analysis of the A D H variants by ultrathin-layer isoelectric focusing, p H range 3-10, of crude extracts from imbibed seeds, followed by enzyme activity staining. The isoelectric points (prs) of the ADH variants were estimated to be 5.5 and 5.7 for Adh-I+ and Adh-l', respectively. Using the procedure described and a newly developed sample applicator strip, it is possible for one person to routinely analyze 1 152 seeds per day using only a single electrophoresis unit. An investigation of a large number of inbred lines, both experimental and commercial hybrids, together with open-pollinated varieties, showed the potential of the method. Among F 1 hybrids, a higher frequency of the Adh-1 I allele was found than among open pollinated varieties, suggesting that F 1 hybrid breeding has resulted in a higher frequency of Adh-l I alleles by selection of linked genes.

An Investigation of Homes with High Concentrations of PCDDs, PCDFs, and/or Dioxin-Like PCBs in House Dust

“…Only PCB 105 has been assigned a TEF by the WHO, and so this is the only one of the three congeners to be reported here. (8) Rudel et al found PCB 105 above their limit of detection (LOD) (∼0.2 micrograms per gram of house dust or 200,000 ppt) in 9 (7.6%) of the 119 homes. The median LOD for PCB 105 in the present study was 2.1 ppt.…”

“…Note that this investigation was initiated in mid-2005, and the determination of outlier status was based on calculation of the TEQs using the 1998 TEFs, but all TEQ results shown here have been recalculated using the 2005 TEFs. (7,8) Twenty house dust results (2.6%) met the statistical criterion to be classified as outliers (see Table II and online supplemental Table II for listing of dust outlier results). If the 2005 TEFs had been used instead of the 1998 TEFs, 15 of the 20 original cases would have met the criterion for being classified as an outlier (i.e., a TEQ more than 2.5 SD above the mean of the logtransformed data), but no new cases met the criterion.…”

Catalyst Inhibition and Deactivation in Homogeneous Hydrogenation

“…In a recent study, the rate of COD hydrogenation in Rh(MonoPhos) 2 (COD)BF 4 was determined as 0.071 min -1 , which is somewhat slower than the corresponding DuPhos complex [20]. In a recent study, the rate of COD hydrogenation in Rh(MonoPhos) 2 (COD)BF 4 was determined as 0.071 min -1 , which is somewhat slower than the corresponding DuPhos complex [20].…”

Anodic Stripping Voltammetry Using a Vibrating Electrode

“…On the other hand, measurements of the reactive copper concentration may be relevant as it is probably related to that fraction of copper which is available to aquatic organisms [20]. However, the reactive fraction should not be equated with the free or inorganic copper fraction as 99% of the copper is known to be organically complexed in these waters [21].…”