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Biomedical subjects

T A Dyer

Publications and source records attributed to T A Dyer.

At least 19 recordsLinked to original sources
PubMed2006

General health promotion in general dental practice--the involvement of the dental team Part 2: A qualitative and quantitative investigation of the views of practice principals in South Yorkshire.

AIM: To investigate the factors that might influence the provision of general health promotion through seven different health interventions by dental teams in general dental practice. METHOD: A mixed-method was used comprising cross-sectional qualitative research using semi-structured interviews of a purposive sample of 10 practice principals, and a cross sectional survey of a practice principal from every dental practice in South Yorkshire, using a self-complete questionnaire. RESULTS: Two core categories emerged from the qualitative data: seeing health or disease and practitioners' views of the structure of dental practice. The former refers to the participants' general outlook and cut across many dimensions constituting the structure of dental practice. Health-orientated dentists were more likely to be involved in prevention and were more open-minded to expanding the dental team's role into general health promotion. However participants perceived that barriers existed to involvement such as time and financial factors, current workload and lack of personal skills. The response rate of useable questionnaires in the cross sectional survey was 84%. Reported levels of involvement in general health promotion were low. Most frequently reported barriers were 'insufficient funding' and 'poor use of time'. 'Poor use of time' and 'lack of training/knowledge' were reported less frequently for professionals complementary to dentistry (PCDs) than dentists (p<0.05). Most dentists agreed that PCDs could be trained to deliver health interventions and would be happy for PCDs to do so in their practice if reported barriers were removed. CONCLUSIONS: Although dental teams' involvement in general health promotion is low, there is willingness to increase involvement, particularly among health-orientated dentists. Some reported barriers to involvement might be removed by impending changes to the GDS in England. Other important factors include a lack of education and workforce shortages of dentists and PCDs. Respondents indicated a high regard for PCDs and there was broad agreement that they were suitable to be involved in this work.

Attitude of Health Personnel↗
PubMed2006

General health promotion in general dental practice--the involvement of the dental team. Part 1: a review of the evidence of effectiveness of brief public health interventions.

OBJECTIVES: To review the evidence of the effectiveness of dentists, dental teams and other healthcare workers in seven different brief public health interventions that might contribute to Government targets in cancer and circulatory disease. The interventions were: smoking prevention, smoking cessation, advice on alcohol consumption, diet counselling, advice on physical exercise, advice on skin cancer prevention and blood pressure monitoring. METHOD: A series of literature reviews, using a generic systematic approach, were undertaken to investigate the effectiveness of dentists, dental teams and other healthcare workers in each intervention. RESULTS: Apart from smoking cessation and dietary advice, no studies were identified on the effectiveness of dentists or dental teams in the interventions investigated. There is some evidence that dentists and dental teams can be effective in smoking cessation. There is minimal evidence for effectiveness in dietary counselling, and that which exists shows only a transient effect. There is evidence that other healthcare workers can have some effect in all interventions, though the effect in preventing skin cancer is questionable. CONCLUSIONS: Due to the paucity of studies undertaken, there is minimal evidence of effectiveness of dentists and dental teams in any of the seven interventions. However other healthcare workers are effective in most of them. Dentists and dental teams' involvement in such brief general health promotion interventions might contribute to Government targets on cancer and circulatory disease.

Alcohol Drinking↗
PubMed1998

Purification of active chloroplast sedoheptulose-1,7-bisphosphatase expressed in Escherichia coli.

Sedoheptulose-1,7-bisphosphatase (SBPase) is an enzyme unique to photosynthetic organisms and has a key role in regulating the photosynthetic Calvin cycle through which nearly all carbon enters the biosphere. This makes SBPase an appropriate target for intensive study. We have expressed wheat SBPase in Escherichia coli either with or without an N-terminal polyhistidine tag. The identity of the recombinant SBPases was confirmed by SDS-PAGE analysis and immunological detection with a specific antibody. Recombinant SBPase with a polyhistidine tag (His-SBPase) was obtained in soluble, active form and purified by one-step metal-chelate chromatography. Like the native enzyme, recombinant His-SBPase was specific for the substrate sedoheptulose-1,7-bisphosphate and required the presence of a reducing agent for activity. Polyclonal antibodies were raised against recombinant SBPase and were then used to determine relative levels of the enzyme in plant extracts. The availability of large amounts of active recombinant SBPase will also allow detailed structural studies by site-directed mutagenesis and X-ray crystallography.

Amino Acid Sequence↗
PubMed1996

Differential gene expression of chloroplast and cytosolic phosphoglycerate kinase in tobacco.

Northern blot analysis of RNA extracted from leaves of increasing age and different organs, indicates that genes encoding both isoenzymes of tobacco phosphoglycerate kinase (PGK, EC 2.7.2.3) are differentially expressed in a developmental and tissue-specific manner. The genes for both chloroplast PGK (chl-PGK) and cytosolic PGK (cyt-PGK) also show light-modulated gene expression in vivo. In dark-grown developing cotyledonary leaves of tobacco both PGK mRNAs are present, but only the concentration of the chl-PGK mRNA increased on illumination. In contrast, on transfer to darkness, the concentration of both mRNAs decreased in light-grown seedlings and then increased again on resumption of illumination.

Amino Acid Sequence↗
PubMed1995

Developmental, circadian and light regulation of wheat ferredoxin gene expression.

A genomic clone encoding the precursor of wheat leaf ferredoxin has been isolated and characterised. The uninterrupted PetF gene encodes a polypeptide of 143 amino acid residues, consisting of an N-terminal presequence of 46 amino acid residues and a mature polypeptide of 97 amino acid residues. Southern blot analysis suggests that six copies of the PetF gene are present in the wheat haploid genome. Northern blot analysis has shown that the genes are both developmentally and light regulated in wheat seedlings and provides evidence that a circadian rhythm regulates the steady-state levels of ferredoxin transcripts. The intact wheat gene and several chimeric constructs, containing portions of the 5'-upstream region fused to the beta-glucuronidase reporter gene, have been introduced into tobacco plants, but levels of beta-glucuronidase activity above background were not detected, suggesting that the 5'-upstream region is unable to function as a promoter in tobacco plants.

Amino Acid Sequence↗
PubMed1992

cDNA and gene sequences of wheat chloroplast sedoheptulose-1,7-bisphosphatase reveal homology with fructose-1,6-bisphosphatases.

The nucleotide sequence encoding the chloroplast enzyme, sedoheptulose-1,7-bisphosphatase [Sed(1,7)P2ase], was obtained from wheat cDNA and genomic clones. The transcribed region of the Sed(1,7)P2ase gene has eight exons (72-507 bp) and seven introns (85-626 bp) and encodes a precursor polypeptide of 393 amino acids. Comparison of the deduced amino acid sequence of Sed(1,7)P2ase with those of fructose-1,6-bisphosphatase [Fru(1,6)P2ase] enzymes from a variety of sources reveals 19% identity, rising to 42% if conservative changes are considered. Most importantly, the amino acid residues which form the active site of Fru(1,6)P2ase are highly conserved in the Sed(1,7)P2ase molecule, indicating a common catalytic mechanism. Interestingly, although the activities of both Sed(1,7)P2ase and chloroplast Fru(1,6)P2ase are modulated by light via the thioredoxin system, the amino acid sequence motif identified as having a role in this regulation in chloroplast Fru(1,6)P2ase is not found in the Sed(1,7)P2ase enzyme.

Amino Acid Sequence↗
PubMed1992

Nuclear genes control changes in the organization of the mitochondrial genome in tissue cultures derived from immature embryos of wheat.

Although the mitochondrial genomes of the Chinese Spring and Aquila varieties of wheat are normally similar in organization, this is not so in tissue cultures initiated from their immature embryos where the mitochondrial genomes of both are rearranged and in different, characteristic, ways. However, the mitochondrial genomes of tissue cultures of reciprocal F1 crosses between these varieties were almost identical to one another, showing that nuclear genes control the rearrangement processes. These rearrangements are either due to the appearance of new structures or else result from changes in the relative amounts of subgenomic components. The severe reduction in the amount of certain molecular configurations in tissue cultures from reciprocal crosses is probably due to the presence of dominant information in the Aquila nuclear genome. Data obtained from tissue cultures initiated from F2 embryos of the cross Aquila x Chinese Spring suggest that at least two complementary genes are involved in this control. In contrast, the presence of new molecular arrangements appears to be under the control of a dominant allelic form of a Chinese Spring gene or genes. Thus, this study demonstrates that at least two sets of nuclear genes control the reorganization of the mitochondrial genome which occurs when tissue cultures are initiated from the immature embryos of wheat.

Blotting, Southern↗
PubMed1991

The chloroplast FBPase gene of wheat: structure and expression of the promoter in photosynthetic and meristematic cells of transgenic tobacco plants.

A gene encoding chloroplast fructose-1,6-bisphosphatase (FBPase) was isolated from a genomic library of wheat DNA. Comparison of the gene sequence obtained with that of a wheat cDNA clone revealed the presence of three introns, each less than 100 bases in length. One of these introns lies in a region that may be involved in the light activation of FBPase catalytic activity. Chimeric gene constructs comprising 1673 bp of the upstream FBPase promoter region in a transcriptional fusion to the beta-glucuronidase (GUS) reporter gene were used to investigate expression in transgenic tobacco plants. Histochemical localization of GUS activity revealed high levels of expression driven by the FBPase promoter sequences in photosynthetically active tissues and, unexpectedly, also in the meristematic regions of shoots, lateral buds and roots. The biological significance of FBPase expression in meristematic regions is not yet clear but this pattern of expression may be explained by the presence in the FBPase promoter of a short DNA sequence motif which is also found in the CaMV 35S viral promoter.

Amino Acid Sequence↗
PubMed1991

Differential expression of the psbB and psbH genes encoding the 47 kDa chlorophyll a-protein and the 10 kDa phosphoprotein of photosystem II during chloroplast development in wheat.

The nucleotide sequence of a region of wheat chloroplast DNA containing the psbB gene for the 47 kDa chlorophyll a-binding protein of photosystem II has been determined. The gene encodes a polypeptide of 508 amino acid residues which is predicted to contain six hydrophobic membrane-spanning regions. The psbB gene is located 562 bp upstream of the psbH gene for the 10 kDa phosphoprotein of photosystem II. A small open reading frame of 38 codons is located between psbB and psbH, and on the opposite strand the psbN gene, encoding a photosystem II polypeptide of 43 amino acid residues, is located between orf38 and psbH. S1 nuclease mapping indicated that the 5' ends of transcripts were located 371 and 183 bp upstream of the psbB translation initiation codon. Predominant transcripts of 2.1 kb and 1.8 kb for psbB and 0.4 kb for psbH were present in RNA isolated from etiolated and greening wheat seedlings. Immunodecoration of Western blots indicated that the 47 kDa polypeptide was absent, or present in very low amounts, in dark-grown tissue and accumulated on greening, whereas the 10 kDa polypeptide was present in similar amounts in both dark-grown and greening seedlings. The 10 kDa polypeptide was phosphorylated in vitro by incubating wheat etioplast membranes with [gamma 32P] ATP.

Amino Acid Sequence↗
PubMed1989

Wheat phosphoglycerate kinase: evidence for recombination between the genes for the chloroplastic and cytosolic enzymes.

We have isolated and sequenced cDNA clones containing the entire coding region of both the chloroplast and cytosolic versions of phosphoglycerate kinase from wheat. Comparison of these sequences reveals a higher than expected level of similarity between the nucleic acids and encoded proteins. Analysis of this data in relation to that for phosphoglycerate kinase sequences of mammals, prokaryotes and yeasts suggests that the wheat genes have recombined. This has resulted in the chloroplast and cytosolic kinases being more similar to each other than would be expected if the chloroplast enzyme had evolved directly from that of a prokaryotic progenitor.

Amino Acid Sequence↗
PubMed1989

psbG is not a photosystem two gene but may be an ndh gene.

A gene of the chloroplast genome has been designated the psbG gene on the basis that in maize the gene product is a 24-kDa polypeptide of photosystem two (PS2) (Steinmetz, A. A., Castroviejo, M., Sayre, R. T., and Bogorad, L. (1986) J. Biol. Chem. 261, 2485-2488). We have located and sequenced the equivalent gene in wheat (Triticum aestivum) and have raised specific antibodies to the gene product following its expression in Escherichia coli as a beta-galactosidase fusion protein. Using these antibodies, we have investigated the location of the gene product in various thylakoid membrane fractions of pea (Pisum sativum). The gene product of apparent molecular mass 27-28 kDa is severely depleted in PS2-enriched membrane preparations and its distribution between stromal and granal regions of the membrane is distinct to that of the psbC gene product which is known to be a core polypeptide of PS2. We therefore conclude that psbG does not code for a component of PS2 but instead suggest that it is present in a novel protein complex of the thylakoid membrane. On the basis of 1) the conserved overlap between psbG and ndhC, a chloroplast gene which shows significant homology to a mitochondrial gene that codes for a subunit of the NADH-ubiquinone oxidoreductase of mitochondria, and 2) sequence similarity between the psbG gene product and the ndh gene product of E. coli, which codes for a respiratory NADH dehydrogenase, we propose that this ill-defined complex functions as a NADH or NADPH-plastoquinone oxidoreductase.

Amino Acid Sequence↗
PubMed1989

Complete coding sequence of wheat phosphoribulokinase: developmental and light-dependent expression of the mRNA.

We have isolated and sequenced a cDNA clone which contains the entire coding sequence of the precursor to a subunit of wheat phosphoribulokinase (PRKase). (The enzyme is a homodimer). The cDNA contains 1533 bp and has an open reading frame of 1212 nucleotides. This encodes a protein with an amino-terminal transit sequence of 53 amino acids, while the part that forms the mature protein contains 351 amino acids and has a molecular weight of 39,200 daltons. A comparison of the wheat amino acid sequence with that already known for the mature protein of spinach reveals that there are identical residues in 86% of the positions but their transit peptides differ substantially from one another. The mature wheat and spinach proteins are identical in a segment of over 50 amino acids near the amino-terminus which is the region believed to be involved in ATP binding and in regulation by light of the catalytic activity of the enzyme. We further demonstrate that the expression of PRKase mRNA in wheat leaves is regulated in a developmental, tissue-specific and light dependent manner. We also show that the light-induced increase in the steady-state levels of this mRNA is dependent on the developmental stage of the leaf.

Amino Acid Sequence↗