Search Results

You are looking at 1 - 10 of 28 items for :

  • "development time" x
  • All content x
Clear All
Acta Biologica Hungarica
Authors: Marina Stamenkovic-Radak, P. Kalajdzic, Tatjana Savic, Marija Savic, Zorana Kurbalija, Gordana Rasic, and M. Andjelkovic

We analyzed the developmental time, egg-to-adult viability, and developmental stability (fluctuating wing size asymmetry) in Drosophila subobscura , maintained for six generations on different concentrations of lead. Development time is significantly affected by generation and lead concentration , but interaction of these factors is not a significant source of variability for this fitness component. Generation and the interaction generation × concentration of lead significantly affect egg-to-adult viability. Levene’s test of heterogeneity of variance showed that variability of FA is not significant in any of the samples. Within both lead concentrations females showed significantly higher FA indices for the wing width than males. Within sexes, a significantly higher FA was found only in females for wing width FA between the control and the lower concentration of lead. The results show that if strong relationship between FA and the studied fitness components exists, it results in a stronger selection of unstable genotypes under lead as a stress factor and, consequently, FA needs to be used with caution as a biomarker in natural populations under environmental stress.

Restricted access

Diosgenin in methanolic extracts of fresh leaves and bulbs of Allium ursinum collected at different times during plant development has been analyzed quantitatively by densitometric TLC. After acid hydrolysis of the extracts, TLC was performed on silica gel plates with n -hexane-acetone 4:1 ( v / v ) as mobile phase. Bands were visualized with 25% H 2 SO 4 in methanol, and diosgenin was quantified densitometrically at 540 nm. Variation in diosgenin content with development time was noted.

Restricted access

R M (log[(1 − R F )/ R F ]) values at different temperatures have been compared for aromatic hydrocarbons with different functional groups in reversed-phase thin-layer chromatography with aqueous binary mobile phases containing methanol, acetonitrile, or tetrahydrofuran. Considerable retention and selectivity variations were observed among the systems investigated. Separation of the solutes at different temperatures can be advantageous, because of these selectivity changes and the shortening of the development time. A horizontal DS-chamber has been developed for performing chromatogram development with temperature control.

Restricted access

Rapid separation of p -hydroxybenzoic acid from methyl p -hydroxybenzoate, ethyl p -hydroxybenzoate, propyl p -hydroxybenzoate, benzoic acid, sodium benzoate, sorbic acid, potassium sorbate, salicylic acid, butylated hydroxyanisole, and butylated hydroxytoluene has been achieved by TLC on the inorganic ion-exchanger stannic silicate with n -hexane-ethyl methyl ketone-acetic acid, 8:2:0.3 ( v/v ), as mobile phase. The development distance was 1 cm and the development time 28 min. Quantitative analysis of the separated p -hydroxybenzoic acid was performed by scanning densitometry at 270 nm. The limits of detection (LOD) and quantitation (LOQ) for p -hydroxybenzoic acid were 0.05 and 0.51 μg per zone, respectively.

Restricted access

An inexpensive, simple, and reproducible SPE-TLC method has been developed and validated for analysis of haloperidol and its three main metabolites in wastewater. Analysis was performed on C 18 silica gel RPTLC plates with methanol containing 0.001% triethylamine as mobile phase. The development time for 10 cm was 70 min. Detection and quantification were performed by exposing TLC plate to iodine vapor and by UV-visible spectrometry. R F values of haloperidol, metabolite I, metabolite II, and metabolite III were 0.20, 0.05, 0.15, and 0.84 respectively. Recovery of haloperidol and its metabolites from wastewater was in the range 80–90%.

Restricted access
JPC - Journal of Planar Chromatography - Modern TLC
Authors: Tadeusz Dzido, Rafał Majewski, Beata Polak, Władysław Gołkiewicz, and Edward Soczewiński

A commercially available horizontal DS chamber has been applied to the planar electrochromatographic (PEC) separation of a dye mixture and of the enantiomers of dl-phenylalanine on non-polar stationary phases with ethanol-buffer or acetonitrile-buffer as mobile phases. The mobile phase was driven electroosmotically by applying a 50–250 V cm −1 field along a 10-cm RP18 TLC plate. Use of a counter-plate to the chromatographic plate enables elimination of problems associated with excessive delivery of mobile phase to the chromatographic adsorbent layer. Compared with conventional TLC separations the efficiency of electrochromatography was higher and the development time shorter.

Restricted access

Rapid separation of methyl p -hydroxybenzoate from ethyl p -hydroxybenzoate, propyl p -hydroxybenzoate, p -hydroxybenzoic acid, benzoic acid, sodium benzoate, butylated hydroxyanisole, and butylated hydroxytoluene has been achieved by TLC on the inorganic ion-exchanger stannic silicate with n -hexane-ethyl methyl ketone-acetic acid, 8 + 2 + 0.3 ( v / v ), as mobile phase. The development distance was 12 cm and development time 30 min. Quantitative analysis of the separated methylparaben was performed by scanning densitometry at λ = 260 nm. The limits of detection (LOD) and quantitation (LOQ) were 0.29 and 0.50 μg per zone, respectively.

Restricted access

The effects of environment and the high molecular weight glutenins on some quality properties (sedimentation volume, % protein content, and starch pasting viscosity) of bread wheat mutant waxy lines were evaluated. Thirty-eight 100% amylose-free F 2 derived F 6 and F 7 lines were used. The results indicated that the environment did not influence sedimentation volume, mixograph parameters and starch viscosity parameters of waxy flour. Variation in the % protein content was determined mainly by the environment. The sedimentation volume and the mixograph peak development time were influenced by the variation at over expression of Bx7 and the mixograph peak development time was influenced by the Glu-D1 locus. One starch viscosity parameter, time to peak viscosity, was influenced by variation at the Glu-A1 locus. This parameter is significantly lower in the waxy lines than the parent line, which shows the influence of the waxy loci. No significant correlation was observed for sedimentation volume, mixograph parameters, protein content and viscosity parameters of waxy lines.

Restricted access

The mixograph performs certain rheological measurements during dough mixing and is a good predictor of wheat end-use quality. The aim of this study was to determine the expression and the heritability of mixing characteristics measured with Mixsmart® software and some quality characteristics in hard red spring wheat parents and their F1 progeny. Six parents varying in midline peak time and envelope peak time were crossed in a half diallel design. Parents and progeny were planted in three different environments. General combining ability (GCA) was a significant source of variation for the measured characteristics, and parents differed widely in terms of GCA effects. Midline-development time, -peak integral and -peak time showed high narrow sense heritability. Envelope peak-integral and -tail width displayed high narrow sense heritability for some, but not all locations. High GCA:SCA (specific combining ability) ratios indicated the prevalence of additive gene effects for midline-development time, -peak integral and -peak time, indicating that these characteristics are largely genetically determined, and that selection for them should lead to genetic gain.

Restricted access

The utilization of continuous-flow biochemical reactors, including biocatalysis, biotransformation, and biochemical interaction based flow-analytical systems, and enzyme reactors are recently the focus of attention to produce fine biochemicals and also show great potential in bioanalytical applications. Continuous-flow biochemical processes implemented in microstructured reactors enable short development time to production scale utilizing enzymatic processes to efficiently fulfill the current needs of the fine biochemical and pharmaceutical industry. Immobilization of the enzymes is preferable because it usually enhances their stability, and in some instances, immobilized enzymes can even be reused multiple times. In this review on the continuous-flow biochemical reactors, first the enzyme immobilization strategies will be briefly discussed followed by summarizing the recent developments in the field of immobilized enzyme microflow reactors for biocatalysis, bioconversion and bioanalytical purposes.

Restricted access