Genetic aspects of variation of protein amounts in maize and pea

Using high-resolution two-dimensional polyacrylamide gel electrophoresis we studied the polymorphism of protein amounts in some genotypes of maize and pea. This type of variability seems to be rather common and insensitive to environmental conditions, as attested by the comparison of the patterns of two maize lines harvested in two different years. A large-scale experiment involving 5 lines, 7 of their hybrids, and 6 organs (or physiological stages) of maize allowed us to examine numerous polypeptides regarding their genetic variability, their amount differences between organs and the inheritance of their abundance. Genetic and organ variations are not independent: polypeptides whose amount varies from one organ to another are, for the most part, genetically variable (59%), while the stable polypeptides are not often genetically variable (18%). We found a striking organ specificity for (i) the extent of quantitative variability (from 2.3-15.4% of the polypeptides), (ii) the occurrence and the type of variation for a given polypeptide (an intensity difference seen in an organ can disappear or even be reversed in another one), (iii) the kind of inheritance (additive/non-additive): combining the 6 organs and the 7 hybrids we found 101 cases of non-additivity (4% of the total) which concern as many as 72 different spots, that is to say that in most cases a polypeptide displaying nonadditivity in an organ seems to display additivity in the other ones. Moreover, for most of the polypeptides with nonadditive inheritance the hybrid spot presents an intensity similar to that of the most intense parental spot.(ABSTRACT TRUNCATED AT 250 WORDS)     

Di-2-pyridyl ketone 2-furoylhydrazone as a reagent for the fluorimetric determination of low concentrations of aluminium

The synthesis and properties of di-2-pyridyl ketone 2-furoylhydrazone as an analytical reagent are described. A rapid procedure for the fluorimetric determination of aluminium at the 10-100 ng ml level, at pH 6.1-6.5 (lambda(exc) 395 nm, lambda(em) 465 nm) has been established. Interferences have been evaluated, and the procedure has been applied satisfactorily to determination of aluminium in sea-water.     

Olefins turned alkylating agents: diastereoselective intramolecular Zr-catalyzed olefin alkylations

The first examples of intramolecular Zr-catalyzed electrophilic alkylation of aryl olefins are disclosed. Substituted carbo- and heterocycles are prepared efficiently and diastereoselectively.     

Spectroscopic investigation of the adsorption and oxidation of thiourea on polycrystalline Au and Au(111) in acidic media

In the present paper, a systematic electrochemical investigation on thiourea (TU) electrooxidation was developed on polycrystalline and (111) single-crystal gold electrodes in 0.1 M perchloric acid. The combination of cyclic voltammetry with in situ Fourier transform infrared spectroscopy (FTIRS) and differential electrochemical mass spectrometry techniques have allowed the nature of the species formed during the electroadsorption and electrooxidation of TU to be established. FTIRS experiments were performed in D2O to clean up the region of the H2O bending around 1600 cm(-1). It was concluded that TU adsorbs tilted on the surface in the 0.05-0.40 VRHE potential range. A dual-path reaction mechanism was evidenced in the oxidation process. The first pathway takes place from adsorbed TU at E > 0.40 VRHE and implies the formation of [Au(I)-(TU)2]+, which is oxidized to NH2CN and S0 at E > 0.80 VRHE. In a following oxidation step at E > 1.20 V, N2, CO2, and HSO4-/SO4(2-) were produced. The second parallel reaction occurs from TU in solution at E > 0.50 VRHE to form (TU)2(2+). All these species were characterized from the spectroscopic experiments. Similar results were obtained for both surfaces.     

Reaction of 1,1,3,3-tetramethyldisiloxane with p-substituted acetophenones in the presence of platinum and rhodium complexes

Hydrosilylation of p-substituted acetophenones XC₆H₄COCH₃ (X = H, Me, MeO, HO, F, Cl, NO₂) with 1,1,3,3-tetramethyldisiloxane in the presence of rhodium and platinum complexes was studied. The Pt(II) complexes are less active but more selective catalysts of hydrosilylation of acetophenones. Six new 1-(1-arylethoxy)-1,1,3,3-tetramethyldisiloxanes were prepared.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1804–1811.Original Russian Text Copyright © 2004 by Zuev, de Vekki, Kuchaev, Vorobev, Skvortsov.This revised version was published online in April 2005 with a corrected cover date.     

Extraction of capsaicins in aerosol defense sprays from fabrics

The use of aerosol defense sprays has increased as a means of self-defense and as a weapon in the commission of a crime. The residue of these sprays is often left behind as physical evidence on a victim's clothing or personal belongings. As the popularity of self-defense weaponry increases, so does the likelihood that it will be encountered in forensic casework. The extraction, recovery from fabrics, and identification of residue from defense sprays is described. The commonly used extraction method of liquid-liquid extraction is compared to solid phase microextraction (SPME) to recover capsaicin and dihydrocapsaicin from cotton swabs. The use of SPME resulted in lower limits of detection and greater recovery efficiency when compared to solvent extraction. SPME also provided more consistent recovery and less variability when compared to solvent extraction. The effect of use of various types of evidence packages on the preservation of this type of evidence is also reported. The collection and analysis of hand swabs after normal discharge of pepper spray canisters was studied indicating the low persistence of these compounds on the hands of the person conducting the spraying. Finally, the results of a real case whereby solvent-solvent extraction did not provide the necessary sensitivity for extracting the capsaicin compounds on the garments of a victim of an alleged spraying and the SPME extraction provided the recovery and identification of the compounds is also presented.     

Regioselective palladium-catalyzed phenylation of ethyl 4-oxazolecarboxylate

The efficient and regioselective palladium-catalyzed C-2 arylation of ethyl 4-oxazolecarboxylate 1 with phenyliodide is described. The different parameters (solvent, base, ligand and catalyst) for the optimal conditions of this arylation process have been screened.     

Cyclooctatetraenecyclopentadienyltitanium iodides

The synthesis and some of the properties of the new complexes (h⁸-C₈H₈)-(h⁵-C₅H₅)TiI and (h⁸-C₈H₈)(h⁵-C₅H₅)TiI₃ are described.     

Voltamperometric determination of kinetin with a carbon paste modified electrode

The electrochemical behaviour of kinetin (6-furfurylaminopurine) on a carbon paste modified with OV-17 silicone electrode, is studied. The determination of kinetin is possible working in square wave voltammetric techniques, reaching limits of determination of 38.7 ng ml⁻¹. The proposed method was successfully applied to determine the cytokinin in extracts of apples (previously spiked with kinetin) and the obtained results were in accordance with the results obtained with HPLC-UV.     

Simultaneous-fluorimetric methods for the determination of ammonia and urea by use of flow injection configurations with dual injection valves

Summary Two fluorimetric methods are proposed for the simultaneous determination of ammonia and urea based on the reaction of the former with o-phthalaldehyde/2-mercaptoethanol and on the use of a dual injection system in which the valves are coupled in series or in parallel. An enzymatic reactor converts urea into ammonia which is determined by the same reaction. These configurations provide very similar results with a linear determination range between 0.5 and 10.0 g ml^–1 and a sampling frequency of 60 h^–1. The proposed methods are very tolerant to foreign species commonly found in water, as shown by applying them to samples of different origins.