The feasibility and acceptability of a rewards system based on food purchasing behaviour in secondary school cashless canteens: the Eat4Treats (E4T) cluster feasibility, non-randomised, controlled intervention study.

Background: Using rewards may be an effective method to positively influence children's eating behaviour but evidence to date is limited, particularly in older children. The cashless canteen systems in schools provides a unique opportunity to implement a food-based reward scheme but intervention development work and feasibility testing is needed. The overall aim of the E4T feasibility study was to examine the feasibility and acceptability of implementing a rewards scheme based on the food purchasing behaviour of pupils in cashless canteens in secondary schools.

A cell-based time-resolved fluorescence assay for selection of antibody reagents for G protein-coupled receptor immunohistochemistry.

A cell-based time-resolved fluorescence (celTRF) immunoassay is described for pre-screening antibodies to G protein-coupled receptor (GPCR) peptides that predicts suitability for immunohistochemistry (IHC). Rat GPCRs were expressed in Saos-2 human osteosarcoma cells via recombinant baculoviruses designed for mammalian cell expression, i.e.

An assessment of the antisense properties of RNase H-competent and steric-blocking oligomers.

The antisense activity and gene specificity of two classes of oligonucleotides (ONs) were directly compared in a highly controlled assay. One class of ONs has been proposed to act by targeting the degradation of specific RNAs through an RNase H-mediated mechanism and consists of C-5 propynyl pyrimidine phosphorothioate ONs (propyne-S-ON). The second class of antisense agents has been proposed to function by sterically blocking target RNA formation, transport or translation and includes sugar modified (2'-O-allyl) ONs and peptide nucleic acids (PNAs).

Strand-invasion of duplex DNA by peptide nucleic acid oligomers.

Polyamide oligomers, termed peptide nucleic acids (PNAs), bind with high affinity to both DNA and RNA and offer both antisense and antigene approaches for regulating gene expression. When a PNA binds to a complementary sequence in a double-stranded DNA, one strand of the duplex is displaced, and a stable D-loop is formed. Unlike oligodeoxynucleotides for which binding polarity is determined by the deoxyribose sugar, the unrestrained polyamide backbone of the PNA could permit binding to a DNA target in an orientation-independent manner.

Antisense and antigene properties of peptide nucleic acids.

Peptide nucleic acids (PNAs) are polyamide oligomers that can strand invade duplex DNA, causing displacement of one DNA strand and formation of a D-loop. Binding of either a T10 PNA or a mixed sequence 15-mer PNA to the transcribed strand of a G-free transcription cassette caused 90 to 100 percent site-specific termination of pol II transcription elongation. When a T10 PNA was bound on the nontranscribed strand, site-specific inhibition never exceeded 50 percent.

DNA triple-helix formation at physiologic pH and temperature.

Oligonucleotides that form a triple helix with duplex DNA offer a novel way to site specifically regulate gene expression in vivo. Triple helices formed by homopyrimidine oligomers containing both cytosine and thymine are stabilized by acid pH and low temperature, and there is little information about triplex formation with these oligomers at both pH 7.5 and 37 degrees C.

Multiple non-B-DNA conformations of polypurine.polypyrimidine sequences in plasmids.

A polypurine.polypyrimidine (Pur.Pyr) sequence with a central interruption in a plasmid can adopt multiple non-B-DNA conformations depending on the conditions as revealed by specific chemical probes (OsO4, diethyl pyrocarbonate, and dimethyl sulfate) and two-dimensional electrophoresis.

Site-specific inhibition of EcoRI restriction/modification enzymes by a DNA triple helix.

The ability of oligopyrimidines to inhibit, through triple helix formation, the specific protein-DNA interactions of the EcoRI restriction and modification enzymes (EcoRI and MEcoRI) with their recognition sequence (GAATTC) was studied. The oligonucleotides (CTT)4 and (CTT)8 formed triplexes in plasmids at (GAA)n repeats containing EcoRI sites. Cleavage and methylation of EcoRI sites within these sequences were specifically inhibited by the oligonucleotides, whereas an EcoRI site adjacent to a (GAA)n sequence was inhibited much less.

Intramolecular DNA triplexes in supercoiled plasmids. II. Effect of base composition and noncentral interruptions on formation and stability.

The effects of interruptions in the homopurine bias and the G+C content of the homopurine.homopyrimidine (pur.pyr) sequences on intramolecular triplex formation and stability in supercoiled plasmids were evaluated.

Intramolecular DNA triplexes in supercoiled plasmids. I. Effect of loop size on formation and stability.

The capacity of four oligopurine.oligopyrimidine (pur.pyr) sequences with different lengths of interruptions in the center [GAA)4(N)n(GAA)4G) (n = 3, 5, 7, and 9) to adopt intramolecular DNA triplexes was evaluated in recombinant plasmids.

The chemistry and biology of unusual DNA structures adopted by oligopurine.oligopyrimidine sequences.

A family of unusual DNA structures has been discovered in segments with predominantly purines in one strand (pur.pyr sequences). These sequences are overrepresented in eukaryotic DNA and have been mapped near genes and recombination hot spots.

Intramolecular DNA triplexes in supercoiled plasmids.

A series of inserts with oligopurine.oligopyrimidine mirror repeat sequences was investigated at the base pair level with specific chemical probes (OsO4 and diethylpyrocarbonate) to evaluate the in vitro existence of intramolecular triplexes. Two parent inserts in recombinant plasmids with (GAA)9 and (AG)12 sequences and three mutant inserts (containing transitions or transversions) revealed that base pair changes at one location affected the chemical reactivity 13 base pairs away.

8-Ketodeoxycoformycin and 8-ketocoformycin as intermediates in the biosynthesis of 2'-deoxycoformycin and coformycin.

An enzyme has been isolated from cell-free extracts of Streptomyces antibioticus that can catalyze the reduction of 8-ketodeoxycoformycin (8-KetodCF) and 8-ketocoformycin (8-ketoCoF) to the naturally occurring nucleoside analogues 2'-deoxycoformycin (dCF) and coformycin (CoF), respectively. The partially purified reductase requires NADPH as the cofactor and stereospecifically reduces the 8-keto group of both ketonucleoside substrates to a hydroxyl group with the R configuration at C-8. This is the same configuration of the hydroxyl group as that of the dCF and CoF isolated from S.

Influence of DNA sequence on the formation of non-B right-handed helices in oligopurine.oligopyrimidine inserts in plasmids.

A systematic study was conducted on seven recombinant plasmids harboring synthetic inserts which had all purines on one strand and all pyrimidines on the complementary strand (Pur.Pyr). The inserts ranged in G+C content from 100% [G19.

Biosynthesis of 2'-deoxycoformycin: evidence for ring expansion of the adenine moiety of adenosine to a tetrahydroimidazo[4,5-d][1,3]diazepine system.

2'-Deoxycoformycin (2'-dCF), a nucleoside antitumor agent produced in trace quantities by Streptomyces antibioticus, has been shown in earlier work to originate from the intact carbon-nitrogen framework of adenosine. Additional experiments using 13C and two-dimensional Fourier transform NMR techniques, together with radiolabeling studies, identify the C-1 of D-ribose, and not the tetrahydrofolate "C-1 pool", as the source of the C-7 carbon in the aglycon of 2'-dCF. These results show that the adenine portion of adenosine (or a nucleotide thereof) undergoes a unique ring expansion, by insertion of a -CH2- unit between the N-1 and C-6 of the adenine ring, to furnish the 1,3-diazepine portion of 2'-dCF.

Evidence for the conversion of adenosine to 2'-deoxycoformycin by Streptomyces antibioticus.

The incorporation and distribution of 14C in 2'-deoxycoformycin, elaborated by Streptomyces antibioticus, were studied with [U-14C]glycine, [U-14C]adenosine and [U-14C]adenine. Similar ratios of 14C in the aglycon and carbohydrate portions of 2'-deoxycoformycin, ara-A, and adenosine isolated from the RNA indicated that [U-14C]adenosine was incorporated into 2'-deoxycoformycin without cleavage of the N-glycosylic bond. Following the addition of [U-14C]adenine, 98% of the 14C isolated from [14C]-2'-deoxycoformycin resided in the aglycon.