Upregulation ofE. coli 38kDa proteins induced by glutaraldehyde and formaldehyde

Exposure of the W3110 strain ofEscherichia coli K12 to low concentrations of glutaraldehyde or formaldehyde results in an unusual pattern of protein expression, as determined by high-resolution, two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). A decline in total protein synthesis is accompanied by the upregulation of three proteins of approximate molecular weight 38 kDa. In the presence of 0.1 mM glutaraldehyde this response occurs within the first 5 min of incubation, and with 0.1 mM formaldehyde, within the first 30 min of incubation. The 38 kDa proteins continue to be expressed at high levels until cell death. Comparison of our 2-D PAGE patterns withE. coli gene-protein and plasmid indexes indicates that one of the proteins may be the major gene product of thepyrC locus. This pattern of protein synthesis may indicate a novelE. coli stress response.     

Partial blocks in the early steps of the chlorophyll synthesis pathway: A common feature of chlorophyll b-deficient mutants

We have analyzed precursor pools in the chlorophyll (Chi) synthesis pathway for a set of eighteen well studied Chl b -defident mutants in monocotyledonous (barley, maize and wheat) and dicotyledonous plants ( Antirrhinum, Arabidopsis , soybean, tobacco and tomato) that form abnormal thylakoid membrane systems. All of these mutants have a partial block in Chl synthesis and nearly all of them accumulate protoporphyrin IX (Proto), the last porphyrin compound common to both heme and Chl synthesis. The large number of mutants at several genetic loci affecting this critical branchpoint in tetrapyrrole biosynthesis suggests that the Mg-chelatase enzyme, catalyzing the first committed step of Chi biosynthesis, is a multimeric complex composed of the products of some of these genetic loci, and perhaps regulated by others. We hypothesize that these mutants are Chi b -deficient and have reduced amounts of light-harvesting antenna complexes (LHCs.) and develop abnormal thylakoid membranes as a direct result of limited Chl synthesis. The observed bottleneck in Chl synthesis can also explain the light-intensity-dependent and temperature-dependent expression of the mutant phenotype. This hypothesis offers a simple explanation for the wide variety of pbenotypes that have been reported for the many Chl-deficient mutants in the literature. Our findings are also consistent with the notion that Chl b is made from "left over" Chl a molecules and suggest that the Chi b -deficient mutants should be considered more appropriately as leaky Chl-deficient mutants.     

Chromatographic techniques for the isolation and purification of lipoproteins

Various modes of chromatography are available for lipoprotein separation. Gel permeation and affinity chromatography are used for preparative purposes and to separate lipoproteins according to size and apolipoprotein content, respectively. Development of rigid supports for gel permeation has led to large improvements in speed and resolution. Reversed-phase high-performance liquid chromatography (HPLC) of apolipoproteins offers the best performance in terms of speed and resolution of structural variants. Due to its high speed and superior resolving power, the recently developed technique of capillary electrophoresis should emerge as an important method for lipoprotein analysis.     

Morphological variability of geographically distinct populations of the estuarine copepod Acartia Tonsa

Variations in the number of spines on the left and right posterior dorsal and posterior margins of the prosome as well as the length of the prosome of Acartia tonsa from three estuaries, the upper western side of the Chesapeake Bay, Montauk Bay near the eastern end of Long Island Sound and the coast of Peru were determined. The length of the prosome and number of spines in each of the four locations were used as an indication of morphological similarity between the populations.     

DNA sequences of the two homoeologous SLR1 genes of Brassica napus cv Westar

The DNA sequence data reported have been lodged in the Genbank, EMBL and DDBJ databases under the accession numbers Z21609 and Z26914     

Caffeoylquinic Acids,Cytotoxic, Antioxidant,Acetylcholinesterase and Tyrosinase Enzyme Inhibitory Activities of Six Inula Species from Bulgaria

Chlorogenic (5‐CQA), 1,5‐, 3,5‐, 4,5‐ and 3,4‐dicaffeoylquinic (DCQA) acids were identified and quantified in the methanol extracts of Inula oculus‐christi L., I. bifrons L., I. aschersoniana Janka var. aschersoniana, I. ensifolia L., I. conyza (Griess .) DC. and I. germanica L. by HPLC analysis. The amount of 5‐CQA varied from 5.48 to 28.44 mg/g DE and the highest content was detected in I. ensifolia. 1,5‐DCQA (4.05–55.25 mg/g DE) was the most abundant dicaffeoyl ester of quinic acid followed by 3,5‐DCQA, 4,5‐DCQA and 3,4‐DCQA. The extract of I. ensifolia showed the highest total phenolic content (119.92±0.95 mg GAE/g DE) and exhibited the strongest DPPH radical scavenging activity (69.41±0.55 %). I. bifrons extract was found to be the most active sample against ABTS^.+ (TEAC 0.257±0.012 mg/mL) and the best tyrosinase inhibitor. The studied extracts demonstrated a low inhibitory effect towards acetylcholinesterase and possessed low cytotoxicity in concentration range from 10 to 300 μg/mL toward non‐cancer (MDCK II) and cancer (A 549) cells.     

Extracurricular Activity Participation and the Acquisition of Developmental Assets: Differences Between Involved and Noninvolved Canadian High School Students

In order to prepare students for adulthood and responsible citizenship, most high schools offer extracurricular activities designed to facilitate the learning of a wide range of competencies. The purpose of this study was to examine how participation in a single or a combination of extracurricular school activities for high school students may impact both their developmental outcomes and their level of school engagement. Results indicated differences between youth who participated in a combination of both sport and nonsport activities as well as sport only activities compared to youth not involved in extracurricular activities on a number of developmental assets and school engagement. It is recommended that parents and adult leaders encourage and support students in their involvement in various extracurricular activities, including high school sport, in order to facilitate positive youth development.     

The Impact of a Sport-Based Life Skill Program on Adolescent Prosocial Values

Abstract

This article describes the implementation and evaluation of a sport-based life skills and community service program. The purpose of this investigation was to determine the impact of a combined life skills and community service program on adolescents' prosocial values. The program was part of a national golf and life skills enrichment academy for adolescents (n = 100). It was hypothesized that the life skills component would have a significant impact on adolescents' prosocial values and that participants (n = 42) who were involved in the community service component following the program, when compared to a comparison group (n = 23), would maintain their increased levels of prosocial values. Results indicated that the program had a significant positive impact on adolescents' prosocial values and that the community service experience positively impacted the adolescents' levels of empathic concern and social responsibility. These results are consistent with existing research on participating in community service.