Preliminary Characterization of Peroxidase Isozymes Isolated from Two Flax Genotrophs

Four peroxidase (EC 1.11.1.7) isozymes were isolated from each of two flax genotrophs. All four isozymes were glycoproteins and all exhibited indoleacetic acid (IAA) oxidase activity. The percentage purity of two of the isozymes was very high; these isozymes differed in percentage carbohydrate and in peroxidase and IAA oxidase specific activities. Three of the isozymes displayed molecular weight values of about 43 000; for the fourth, molecular weight was considerably higher. Corresponding isozymes from the genotrophs and from two other flax genotypes displayed molecular weight differences which corresponded to electrophoretic relative mobility differences. Enzyme yield per unit fresh weight was higher for one genotroph than the other, and the balance between peroxidase activity and IAA oxidase activity between the genotrophs was different

Measurement of Activity of Peroxidase Isoenzymes in Flax (\u3cem\u3eLinum usitatissimum\u3c/em\u3e)

Peroxidase isoenzynles may be separated on acrylamide gels and then detected by supplying the substrate in an appropriate reaction system. One such system frequently used contains guaiacol as the hydrogen donor, although this compound has certain drawbacks. Ways of circumventing these drawbacks are suggested, so that quantitative estimates of the activity of individual peroxidase isoenzymes may be obtained

Shigella flexneri utilize the spectrin cytoskeleton during invasion and comet tail generation

<p>Abstract</p> <p>Background</p> <p>The spectrin cytoskeleton is emerging as an important host cell target of enteric bacterial pathogens. Recent studies have identified a crucial role for spectrin and its associated proteins during key pathogenic processes of <it>Listeria monocytogenes </it>and <it>Salmonella </it>Typhimurium infections. Here we investigate the involvement of spectrin cytoskeletal components during the pathogenesis of the invasive pathogen <it>Shigella flexneri.</it></p> <p>Results</p> <p>Immunofluorescent microscopy reveals that protein 4.1 (p4.1), but not adducin or spectrin, is robustly recruited to sites of <it>S. flexneri </it>membrane ruffling during epithelial cell invasion. Through siRNA-mediated knockdowns, we identify an important role for spectrin and the associated proteins adducin and p4.1 during <it>S. flexneri </it>invasion. Following internalization, all three proteins are recruited to the internalized bacteria, however upon generation of actin-rich comet tails, we observed spectrin recruitment to those structures in the absence of adducin or p4.1.</p> <p>Conclusion</p> <p>These findings highlight the importance of the spectrin cytoskeletal network during <it>S. flexneri </it>pathogenesis and further demonstrate that pathogenic events that were once thought to exclusively recruit the actin cytoskeletal system require additional cytoskeletal networks.</p

Isolation of Peroxidase Isozymes from Two Flax Genotypes by Column Chromatography

Isolation of the four major peroxidase isozymes (isozymes 1, 2, 3, and 4) of two flax genotypes was achieved by modifying the procedure used by Shannon et al. (1966) for the isolation of horseradish peroxidase isozymes. The net positive and net negative charges of isozymes 1, 2, and 4 were different. Isozyme 3 resembled isozyme 4 in charge but differed in apparent molecular weight. The chromatographic elution profiles of both genotypes were the same. Anionic gel electrophoresis demonstrated that after isolation and repurification, relative mobility differences existed between the corresponding isozymes of the two genotypes for all four isozymes

Implementing a Current Research Information System (CRIS) in Canada

The practice of research information management (RIM) is becoming more important as the research environment becomes increasingly complex, competitive and globalized. National mandates and requirements of national funding agencies regarding open access and research data management are creating added incentives for universities to showcase their publications and make them available in an open access format. Libraries are well situated to offer expertise throughout the adoption of a research information management system by a university. In aligning themselves with the wider strategic plans of the institution, libraries can use this as a platform to further their own goals and communicate their value and place in the institution by championing open access, ensuring discoverability and supporting the researcher endeavour. Dalhousie University is in the process of implementing a Research Information System (RIS) with the goal of providing a number of benefits to the university and its researchers. RIS serve to aid researchers when applying to funding agencies by creating consistent, standardized CVs, decrease workload when generating annual reports, increase the visibility and discoverability of an institution to potential collaborators and research contacts, augment the research currently being performed at an institution and make it more widely available, and manage and measure the research impact of individual researchers and institutions. While some challenges exist at Dalhousie that require mitigation and attention, the institution stands to benefit greatly from the implementation of this system

Inter-individual variation in nucleotide excision repair in young adults: effects of age, adiposity, micronutrient supplementation and genotype

Nucleotide excision repair (NER) is responsible for repairing bulky helix-distorting DNA lesions and is essential for the maintenance of genomic integrity. Severe hereditary impairment of NER leads to cancers such as those in xeroderma pigmentosum, and more moderate reductions in NER capacity have been associated with an increased cancer risk. Diet is a proven modifier of cancer risk but few studies have investigated the potential relationships between diet and NER. In the present study, the plasmid-based host cell reactivation assay was used to measure the NER capacity in peripheral blood mononuclear cells from fifty-seven volunteers aged 18–30 years before and after 6 weeks of supplementation with micronutrients (selenium and vitamins A, C and E). As a control, nine individuals remained unsupplemented over the same period. Volunteers were genotyped for the following polymorphisms in NER genes: ERCC5 Asp1104His (rs17655); XPC Lys939Gln (rs2228001); ERCC2 Lys751Gnl (rs13181); XPC PAT (an 83 bp poly A/T insertion–deletion polymorphism in the XPC gene). NER capacity varied 11-fold between individuals and was inversely associated with age and endogenous DNA strand breaks. For the first time, we observed an inverse association between adiposity and NER. No single polymorphism was associated with the NER capacity, although significant gene–gene interactions were observed between XPC Lys939Gln and ERCC5 Asp1104His and XPC Lys939Gln and ERCC2 Lys751Gnl. While there was no detectable effect of micronutrient supplementation on NER capacity, there was evidence that the effect of fruit intake on the NER capacity may be modulated by the ERCC2 Lys751Gnl single nucleotide polymorphism

Systemic RNAi mediated gene silencing in the anhydrobiotic nematode Panagrolaimus superbus

<p>Abstract</p> <p>Background</p> <p>Gene silencing by RNA interference (RNAi) is a powerful tool for functional genomics. Although RNAi was first described in <it>Caenorhabditis elegans</it>, several nematode species are unable to mount an RNAi response when exposed to exogenous double stranded RNA (dsRNA). These include the satellite model organisms <it>Pristionchus pacificus </it>and <it>Oscheius tipulae</it>. Available data also suggest that the RNAi pathway targeting exogenous dsRNA may not be fully functional in some animal parasitic nematodes. The genus <it>Panagrolaimus </it>contains bacterial feeding nematodes which occupy a diversity of niches ranging from polar, temperate and semi-arid soils to terrestrial mosses. Thus many <it>Panagrolaimus </it>species are adapted to tolerate freezing and desiccation and are excellent systems to study the molecular basis of environmental stress tolerance. We investigated whether <it>Panagrolaimus </it>is susceptible to RNAi to determine whether this nematode could be used in large scale RNAi studies in functional genomics.</p> <p>Results</p> <p>We studied two species: <it>Panagrolaimus </it>sp. PS1159 and <it>Panagrolaimus superbus</it>. Both nematode species displayed embryonic lethal RNAi phenotypes following ingestion of <it>Escherichia coli </it>expressing dsRNA for the <it>C. elegans </it>embryonic lethal genes <it>Ce-lmn-1 </it>and <it>Ce-ran-4</it>. Embryonic lethal RNAi phenotypes were also obtained in both species upon ingestion of dsRNA for the <it>Panagrolaimus </it>genes <it>ef1b </it>and <it>rps-2</it>. Single nematode RT-PCR showed that a significant reduction in mRNA transcript levels occurred for the target <it>ef1b </it>and <it>rps-2 </it>genes in RNAi treated <it>Panagrolaimus </it>sp. 1159 nematodes. Visible RNAi phenotypes were also observed when <it>P. superbus </it>was exposed to dsRNA for structural genes encoding contractile proteins. All RNAi phenotypes were highly penetrant, particularly in <it>P. superbus</it>.</p> <p>Conclusion</p> <p>This demonstration that <it>Panagrolaimus </it>is amenable to RNAi by feeding will allow the development of high throughput methods of RNAi screening for <it>P. superbus</it>. This greatly enhances the utility of this nematode as a model system for the study of the molecular biology of anhydrobiosis and cryobiosis and as a possible satellite model nematode for comparative and functional genomics. Our data also identify another nematode infraorder which is amenable to RNAi and provide additional information on the diversity of RNAi phenotypes in nematodes.</p

Diels-Alder Trapping of Photochemically Generated o-Quinodimethane Intermediates: An Alternative Route to Photocured Polymer Film Development

Photolysis of o-methylphenyl ketones generates bis-o-quinodimethane intermediates that can be trapped in situ by dienophiles through Diels-Alder cycloadditions. This well-known photochemical process is applied to a series of six new photoreactive monomers containing bis-(o-methylphenyl ketone) functionalities combined with diacrylate and triacrylate ester monomers for the development of acrylic ester copolymer blends. Irradiation of cyclohexanone solutions of the bis-(o-methylphenyl ketone)s and acrylate esters produce thin polymer films. Solid state 13C NMR data indicated 47- 100% reaction of the bis-(o-methylphenyl ketone)s, depending on experimental conditions, to yield the desired products. DSC and TGA analyses were performed to determine the glass transition temperature, T,, and onset of decomposition, Td, of the resulting polymer films. A statistical Design of Experiments approach was used to obtain a systematic understanding of the effects of experimental variables on the extent of polymerization and the final polymer properties

Expression profiling and cross-species RNA interference (RNAi) of desiccation-induced transcripts in the anhydrobiotic nematode Aphelenchus avenae.

BACKGROUND: Some organisms can survive extreme desiccation by entering a state of suspended animation known as anhydrobiosis. The free-living mycophagous nematode Aphelenchus avenae can be induced to enter anhydrobiosis by pre-exposure to moderate reductions in relative humidity (RH) prior to extreme desiccation. This preconditioning phase is thought to allow modification of the transcriptome by activation of genes required for desiccation tolerance. RESULTS: To identify such genes, a panel of expressed sequence tags (ESTs) enriched for sequences upregulated in A. avenae during preconditioning was created. A subset of 30 genes with significant matches in databases, together with a number of apparently novel sequences, were chosen for further study. Several of the recognisable genes are associated with water stress, encoding, for example, two new hydrophilic proteins related to the late embryogenesis abundant (LEA) protein family. Expression studies confirmed EST panel members to be upregulated by evaporative water loss, and the majority of genes was also induced by osmotic stress and cold, but rather fewer by heat. We attempted to use RNA interference (RNAi) to demonstrate the importance of this gene set for anhydrobiosis, but found A. avenae to be recalcitrant with the techniques used. Instead, therefore, we developed a cross-species RNAi procedure using A. avenae sequences in another anhydrobiotic nematode, Panagrolaimus superbus, which is amenable to gene silencing. Of 20 A. avenae ESTs screened, a significant reduction in survival of desiccation in treated P. superbus populations was observed with two sequences, one of which was novel, while the other encoded a glutathione peroxidase. To confirm a role for glutathione peroxidases in anhydrobiosis, RNAi with cognate sequences from P. superbus was performed and was also shown to reduce desiccation tolerance in this species. CONCLUSIONS: This study has identified and characterised the expression profiles of members of the anhydrobiotic gene set in A. avenae. It also demonstrates the potential of RNAi for the analysis of anhydrobiosis and provides the first genetic data to underline the importance of effective antioxidant systems in metazoan desiccation tolerance.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are