Phenotypic and molecular characterization of plants regenerated from non-cryopreserved and cryopreserved wild Solanum lycopersicum mill. Seeds.

BACKGROUND: Before cryopreservation is routinely used, its effect on the trueness-to-type of the regenerated plant material needs to be evaluated. OBJECTIVE: In this work, we studied the effect of seed cryopreservation on the phenotypic and molecular characteristics of wild Solanum lycopersicum Mill. plants. METHODS: Thirty-five morphological traits of plants regenerated from cryopreserved seeds were compared to those measured on plants regenerated from non-cryopreserved seeds. RESULT: No statistically significant differences were observed between cryopreserved and non-cryopreserved samples, either in the first or in the second generation post-liquid nitrogen exposure. However, at the molecular level, the genetic analyses performed on the second generation plants germinated from control and cryopreserved seeds using 14 nuclear Simple Sequences Repeats (SSR) markers uncovered some changes in microsatellite length between control and cryopreserved samples. These results confirm at the botanical phenotype level the effectiveness of seed cryostorage for conservation and regeneration of true-to-type S. lycopersicum plants. CONCLUSION: Further experiments are required to clarify potential phenotypic effects of the changes observed in the DNA.

Ergonomic evaluation in a values transportation company in Venezuela.

UNLABELLED: The objective was to analyze the work activity and identify risk factors that could account for musculoskeletal disorders in the upper extremities, shoulder and neck of workers of a transport values company in Venezuela. The methods used were: collective interview, tasks observation, evaluation of posture with RULA method and evaluation of repetitive motions with the OCRA method. Five workstations were evaluated. Main problem perceived by workers was: exposure to chemical and biological hazards when handling paper money and coins; inadequate chairs and close supervision. The postures level risk was 1 or 2 for the RULA scale. Only two workstations showed ligth and medium risk level by OCRA method. CONCLUSION: The factors identified that could explain the musculoskeletal changes were: wrist repetitive flexion and extension, shoulder elevation, lifting weight above shoulder height, elbow repetitive flexion and extension, neck flexion, extended work journey, work overload, high responsibility and strict supervision by a video camera.

Capillary electrophoretic application of 1-alkyl-3-methylimidazolium-based ionic liquids.

Ionic substances with melting points at or close to room temperature are referred to as ionic liquids. Interest in ionic liquids for their potential in different chemical processes is increasing, because they are environmentally benign and are good solvents for a wide range of both organic and inorganic materials. In this study, a capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts is reported. The method, in which 1-alkyl-3-methylimidazolium-based ionic liquids are used as the running electrolytes, is simple and reproducible. The separation mechanism seems to involve association between the imidazolium cations and the polyphenols. The role of the alkyl substituents on the imidazolium cations was investigated and will be discussed.

Morphological and functional characterization of beige mouse adrenomedullary secretory vesicles.

We tested whether the giant secretory granules observed in the mast cells of the naturally occurring mutant beige mouse (BM) (C57BL/6N-bg) were also present in the adrenal chromaffin cells. The presence of large chromaffin granules (CG) would be a valuable tool for the study of exocytosis in neuronal tissues. Conversely, the observation of large vesicles within chromaffin cells that are different from CG could indicate that CG are of a different origin than granules of mast cells. Ultrastructural analysis demonstrated the presence of large lysososmal-like vesicles in the BM, and also a discrete increase in the number of CG with diameters larger than 240 nm but not of giant CG. In addition, amperometric measurements of single-event exocytosis, using carbon fiber microelectrodes, showed no differences between the quantal size of secretory events from BM and wildtype or bovine chromaffin cells. Minor but significant differences were found between the kinetics of exocytosis in BM cells andwild-type mouse cells. We conclude that CG, but not the abnormal-sized vesicles found in BM chromaffin cells contribute to the catecholamine secretion and that abnormal secretory granules are not present in adrenergic cell lineage.

Quantitative determination of clenbuterol, salbutamol and tulobuterol enantiomers by capillary electrophoresis.

Enantiomers of clenbuterol, salbutamol and tulobuterol were directly separated and quantitated from a spiked sample by capillary electrophoresis (CE) using sulfaited beta-cyclodextrin (SCD) as chiral selector and phosphate as running buffer. The SCD and buffer concentration, pH and field strength were the parameters studied to optimize the separation. Optimal separation was obtained using 50 mM of phosphate monobasic at pH = 2.24, 0.25% (w/w) of sulfated cyclodextrin and a field strength of 10 kV, with 20 min total time analysis. Comparison between two different injection modes (hydrodynamic and electrokinetic) was made. In the hydrodynamic mode, repeatability (expressed as relative standard deviation, RSD) was less than 1.2% for migration times for all the analyte peaks and less than 2% for peak area percentages. With respect to reproducibility, RSD was less than 3.8% for migration time and less than 3% for peak area percentages. Calibration curves were set up for two different sample concentration ranges (1 to 10 microg mL(-1) and 160-800 ng mL(-1), of each of the racemates studied). Although the electrokinetic injection mode for an aqueous sample appeared to suffer from some enantiodiscrimination, calibration curves were linear in the range between 1 and 10 ng mL(-1) with regression coefficients ranging from 0.9996 to 0.9952. As in the case of hydrodynamic injection, the method was tested with a spiked sample.

A comparison of phosphated and sulfated beta-cyclodextrins as chiral selectors for capillary electrophoresis.

The enantioseparation capabilities of three different functionalized beta-cyclodextrins, two sulfated beta-cyclodextrins with 4 and 15 nominal degrees of substitution and a phosphated beta-cyclodextrin with 8 degrees of substitution, were compared. While anodic detection was used with both sulfated cyclodextrins, the phosphated cyclodextrin required cathodic detection suggesting either lower ionization of the phosphated cyclodextrin or generally lower affinity of the analytes for the phosphated cyclodextrin. The effects of several experimental parameters were evaluated with respect to enantioseparation. The degrees of substitution of the cyclodextrin, pH of the background electrolyte as well as the concentration of the functionalized beta-cyclodextrin, each had a significant influence on the successful enantiomeric separation of the chiral drugs investigated.

Continuous free flow electrophoresis for preparative chiral separations of piperoxan using sulfated beta-cyclodextrin.

Continuous free flow electrophoresis was investigated as a tool for the preparative chiral separation of piperoxan using a sulfated cyclodextrin chiral additive. In the absence of chiral additive, the sample stream was deflected cathodically. However, the presence of sulfated cyclodextrin in the run buffer caused anodic deflection and splitting of the sample stream into two streams, each enriched in one enantiomer. Although the sulfated cyclodextrin used was comprised of a mixture of homologues and isomers, this polydispersity did not seem to significantly impact band dispersion. Sample introduction rates ranged from approximately 0.9-7.2 mg h-1. Maximum resolution was 0.53, using an applied voltage of 220 V, buffer composition of 0.075% sulfated cyclodextrin, 7.6 mM citrate (pH 3), 4.5 degrees C.

Tetraethylammonium tetrafluoroborate: a novel electrolyte with a unique role in the capillary electrophoretic separation of polyphenols found in grape seed extracts.

A capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts was developed using a quaternary ammonium salt as the main electrolyte solution. Seven polyphenols were separated and identified. The separation mechanism seems to involve association between quaternary ammonium cations and the polyphenols. Migration times roughly correlate with the size of the known phenols. The role of the alkyl substituents on the quaternary ammonium ions was investigated and is discussed. The method of analysis proposed herein exhibits high reproducibility in terms of migration times for a complex mixture using a single component background electrolyte.