Showing papers by "University of Dundee published in 1992"
4,800 citations
TL;DR: It is shown that p53 DNA binding is cryptic but can be activated by cellular factors acting on a C-terminal regulatory domain of p53, which may be critical in regulation of its ability to arrest cell growth and thus its tumor suppressor function.
930 citations
TL;DR: The results suggest that sustained activation of theMAP kinase cascade may be required for MAP kinase to enter the nucleus, where it may initiate the gene transcription events required for neuronal differentiation of PC12 cells.
Abstract: Stimulation of PC12 cells with nerve growth factor (NGF) increased mitogen-activated protein kinase kinase (MAPKK) activity > 20-fold after 5 min to a level that was largely sustained for at least 90 min. MAPKK activity was stimulated to a similar level by epidermal growth factor (EGF), but peaked at 2 min, declining thereafter and returning to basal levels after 60-90 min. Activation of MAPKK by either growth factor occurred prior to the activation of MAP kinase, consistent with MAPKK being the physiological activator of MAP kinase. The results demonstrate that the transient activation of MAPKK by EGF and its sustained activation by NGF underlies the transient and sustained activation of MAP kinase induced by EGF and NGF respectively. NGF or EGF induced the same two forms of MAPKK that were resolved on a Mono Q column. The Peak-1 MAPKK was activated initially and partially converted into the more acidic peak-2 MAPKK after prolonged growth-factor stimulation. The Peak-2 MAPKK was 20-fold more sensitive to inactivation by the catalytic subunit of protein phosphatase 2A. Stimulation with NGF caused a striking translocation of MAP kinase from the cytosol to the nucleus after 30 min, but not nuclear translocation of MAP kinase occurred after stimulation with EGF. The results suggest that sustained activation of the MAP kinase cascade may be required for MAP kinase to enter the nucleus, where it may initiate the gene transcription events required for neuronal differentiation of PC12 cells.
892 citations
TL;DR: The ability to visualize repair intermediates in the absence of PCNA facilitates dissection of the multiprotein reaction that leads to incision of damaged DNA in a major pathway of cellular defense against mutagens.
806 citations
TL;DR: It is concluded that raf protein kinase is upstream of MAP kinases and is either a MAP kinase kinaseKinase or aMAP kinase Kinase kinases kinase, independently of cellular ras.
768 citations
TL;DR: In this article, the implications for accounting of placing the environment at the centre of the analysis are investigated, focusing on an accounting's potential for contribution to accountability and transparency in participative democracy, the potential for non-financial accounts of the biosphere and the use of current accounting techniques for the operationalisation of an accounting for sustainability.
Abstract: Concern for the natural environment has not occupied a prominent role in accounting scholarship and practice. This paper attempts to redress this omission by investigating the implications for accounting of placing the environment at the centre of the analysis. The paper introduces the principles of this “deep green” position and explores how accounting might articulate them. Whilst there may be no place for what we currently consider to be conventional financial accounting in any “green utopia” the paper does not attempt to operationalise, within a non-green world, certain of the principles of the green position. Emphasis is placed on an accounting's potential for contribution to accountability and transparency in participative democracy, the potential for non-financial accounts of the biosphere and, perhaps most contentiously, the use of current accounting techniques for the operationalisation of an accounting for sustainability.
722 citations
TL;DR: The results suggest that MAPKAP kinase‐2 is the enzyme responsible for the phosphorylation of these small heat shock proteins in mammalian cells.
577 citations
TL;DR: In this article, the authors used bacterial expression systems to produce fragments of human p53 and then isolated and characterized new monoclonal antibodies to p53, which are suitable for the measurement of p53 in ELISA, immunoblotting and immunoprecipitation analyses.
552 citations
TL;DR: N isotope discrimination is also useful in tracking N through food webs, and hence, back to combined N sources for plants, while potentially very useful, a number of pitfalls are discussed in its ecological use in both terrestrial and aquatic systems.
Abstract: Nitrogen stable isotope (^^N, ^*N) natural abundance has been much less used than carbon isotopes (^^C, ^^C) in plant physiology and ecology. Analytical problems, the lower fractional abundance of ^^N than of ^^C in the biosphere, the greater complexity of the N cycle relative to the C cycle, and smaller expressed discriminations in nature, are contributing factors- The major N pools, globally, have different isotope signatures: atmospheric N2 is ^^N-depleted relative to organic N (including sedimentary N), a situation resulting from a greater expressed discrimination in the organic N to N2 (via denitrification) reaction than of diazotrophy during accumulation of the reduced N. Essentially ail of the enzymes except nitrogenase which transform N compounds show discrimination against ^^N, although for glutamine synthetase, and the amination of 2oxoglutarate and pyruvate, this is only seen in terms of NH4 rather than the true substrate, NH3. Discrimination is expressed in various N interconversio ns within piants, leading to substantial differences in h^^H (up to 12%o) among N compounds and macroscopic plant parts. N isotope fractionation during assimilation of exogenous combined N is often much lower than that expected from studies of isolated enzymes due to processes which show very little discrimination, such as limitation by transport through aqueous solution and membranes. Application of ^^N/^'^N discrimination studies to plant ecology have concentrated largely on distinguishing diazotrophy from N supplied from combined N, based on the lower ^^N/^'^N in diazotrophs due to the higher ^^N/^'*N of combined N sources not being offset by fractionation during uptake. While potentially very useful, a number of pitfalls are discussed in its ecological use in both terrestrial and aquatic systems. N isotope discrimination is also useful in tracking N through food webs, and hence, back to combined N sources for plants.
549 citations
TL;DR: Results indicate that MAP kinase activates at least two distinct protein kinases, suggesting that it represents a point at which the growth factor‐stimulated protein kinase cascade bifurcates.
Abstract: A novel protein kinase, which was only active when phosphorylated by the mitogen-activated protein kinase (MAP kinase), has been purified 85,000-fold to homogeneity from rabbit skeletal muscle. This MAP kinase activated protein kinase, termed MAPKAP kinase-2, was distinguished from S6 kinase-II (MAPKAP kinase-1) by its response to inhibitors, lack of phosphorylation of S6 peptides and amino acid sequence. MAPKAP kinase-2 phosphorylated glycogen synthase at Ser7 and the equivalent serine (*) in the peptide KKPLNRTLS*VASLPGLamide whose sequence is similar to the N terminus of glycogen synthase. MAPKAP kinase-2 was resolved into two monomeric species of apparent molecular mass 60 and 53 kDa that had similar specific activities and substrate specificities. Peptide sequences of the 60 and 53 kDa species were identical, indicating that they are either closely related isoforms or derived from the same gene. MAP kinase activated the 60 and 53 kDa forms of MAPKAP kinase-2 by phosphorylating the first threonine residue in the sequence VPQTPLHTSR. Furthermore, Mono Q chromatography of extracts from rat phaeochromocytoma and skeletal muscle demonstrated that two MAP kinase isoforms (p42mapk and p44mapk) were the only enzymes in these cells that were capable of reactivating MAPKAP kinase-2. These results indicate that MAP kinase activates at least two distinct protein kinases, suggesting that it represents a point at which the growth factor-stimulated protein kinase cascade bifurcates.
449 citations
TL;DR: The results of this study support the conclusion that the enhanced locomotor response to nicotine observed in animals pretreated with the drug prior to the test day is associated with potentiation of its effects on dopamine secretion in the NAc.
Abstract: 1. The effects of acute and subchronic nicotine and (+)-amphetamine on the extracellular levels of dopamine and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in nucleus accumbens (NAc) have been studied in conscious, freely-moving rats by use of in vivo microdialysis. 2. In rats which had been habituated to the test apparatus for approximately 80 min, the acute subcutaneous (s.c.) administration of nicotine (0.1 or 0.4 mg kg-1) caused a dose-dependent increase (P less than 0.01) in spontaneous activity and evoked significant increases (P less than 0.05) in the extracellular levels of DOPAC and HVA. 3. Measurements made 24 h after the last injection of nicotine showed that pretreatment with the higher doses tested (0.4 mg kg-1) resulted in increased basal levels of dopamine (P less than 0.01) and decreased basal levels of DOPAC (P less than 0.05) in the NAc dialysates. 4. Pretreatment with nicotine (0.1 or 0.4 mg kg-1 daily for 5 days) enhanced the effects of the drug on spontaneous locomotor activity and enhanced the effects of the drug on extracellular levels of dopamine to the extent that the response became significant (P less than 0.05). 5. If a dopamine uptake inhibitor, nomifensine, was added to the Ringer solution used to dialyse the probe, the s.c. administration of both acute and subchronic nicotine (0.4 mg kg-1) resulted in significant increases (P less than 0.05) in the dopamine concentration in the dialysate. Under these conditions, pretreatment with nicotine prior to the test day prolonged (P less than 0.05) the dopamine response to a challenge dose of nicotine.6. Subcutaneous injections of (+)-amphetamine (0.2 or 0.5 mg kg-') evoked dose-dependent increases in both spontaneous activity and the concentration of dopamine in NAc dialysates. These responses were unaffected by 5 days pretreatment with the drug.7. The results of this study support the conclusion that the enhanced locomotor response to nicotine observed in animals pretreated with the drug prior to the test day is associated with potentiation of its effects on dopamine secretion in the NAc.
Journal Article•
TL;DR: A technique of subtotal endoscopic oesophagectomy through the right thoracoscopic approach has been used in five patients, four with cancer and one with benign motility disorder and one patient developed left vocal cord palsy which prolonged this.
Abstract: A technique of subtotal endoscopic oesophagectomy through the right thoracoscopic approach is described. It has been used in five patients, four with cancer and one with benign motility disorder. The operative blood loss during the endoscopic dissection stage was unmeasurable in four patients and amounted to 300 ml in one. The mean (range) duration of the endoscopic dissection was 3.3 (3.0-4.0) h and of the total procedure was 5.5 (4.5-7.5) h. After the operation, the mean (range) duration of stay in the intensive care unit was 19.5 (16-26) h. From the time of the operation, the mean (range) hospital stay was 11 (8-18) days. One patient developed left vocal cord palsy which prolonged this.
TL;DR: In this article, a characterization of the subdifferential of matrix norms from two classes, orthogonally invariant norms and operator (or subordinate) norms, is given for some special cases.
TL;DR: A "complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide is described, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction.
Abstract: IN the hereditary blistering condition epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling–Meara epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm1; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a "complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.
TL;DR: The distinctive properties of smooth and skeletal muscle myosin phosphatases are explained by interaction of PP1 beta with different proteins and (in conjunction with earlier analysis of the glycogen-associated phosphatase) establish that the specificity and subcellular location ofPP1 is determined by its interaction with a number of specific targetting subunits.
Abstract: The major protein phosphatase that dephosphorylates smooth-muscle myosin was purified from chicken gizzard myofibrils and shown to be composed of three subunits with apparent molecular masses of 130, 37 and 20 kDa, the most likely structure being a heterotrimer. The 37-kDa component was the catalytic subunit, while the 130-kDa and 20-kDa components formed a regulatory complex that enhanced catalytic subunit activity towards heavy meromyosin or the isolated myosin P light chain from smooth muscle and suppressed its activity towards phosphorylase, phosphorylase kinase and glycogen synthase. The catalytic subunit was identified as the β isoform of protein phosphatase-1 (PP1) and the 130-kDa subunit as the PP1-binding component. The distinctive properties of smooth and skeletal muscle myosin phosphatases are explained by interaction of PP1β with different proteins and (in conjunction with earlier analysis of the glycogen-associated phosphatase) establish that the specificity and subcellular location of PP1 is determined by its interaction with a number of specific targetting subunits.
TL;DR: The beneficial impact of having previously received AIDS/HIV-relevant education on beliefs concerning the controllability of the epidemic and on feeling worried about everyday contact with a person with HIV/AIDS, was most marked among those who had left school.
Abstract: A survey examined health beliefs and intentions among 690 16-18 year-olds in Dundee. Respondents in the younger cohort (n = 363) were classified according to their educational situation (at school vs left) and self-reports of having received AIDS/HIV-relevant health education. Both remaining in school and receiving AIDS/HIV-relevant health education had independent beneficial effects, but the effects of leaving school also interacted with sex of respondent and with amount of relevant education received prior to leaving. Males' and females' reliance on mass media and other information sources diverged once they left school, indicating that males who leave school early are most likely to disregard useful or important information regarding AIDS. Consistent with this finding, leaving school reduced the difference between males' and females' intention to use condoms with a new partner. The beneficial impact of having previously received AIDS/HIV-relevant education on beliefs concerning the controllability of the epidemic and on feeling worried about everyday contact with a person with HIV/AIDS, was most marked among those who had left school. The results are discussed in terms of their implications for health education strategies.
TL;DR: Using this reagent, the cDNA encoding the complete normal human p53 protein was expressed in Escherichia coli using an expression system based on the bacteriophage T7 promoter and it is found that aberrant expression of p53 is a frequent feature of human breast cancer.
Abstract: A cDNA encoding the complete normal human p53 protein was expressed in Escherichia coli using an expression system based on the bacteriophage T7 promoter. The cDNA was adapted so that the full-length protein was produced without fusion to any other sequence. Large amounts of the protein were isolated and the purified protein used to produce very high titre polyclonal antibodies to p53. These new antibodies permit the sensitive detection of p53 and p53 complexes in ELISA and immunoblotting assays. Most importantly, they also permit the detection of p53 in archival tumour material that has been conventionally fixed in formalin and embedded in paraffin wax. Using this reagent we have found that aberrant expression of p53 is a frequent feature of human breast cancer. We are able to recognise six different classes of p53 expression pattern that may be of help in the subclassification of breast tumours.
TL;DR: Phylogenetic analysis of sequences shows that the degree of sequence divergence in the retrotransposon populations between any pair of species is proportional to the evolutionary distance between those species, which implies that sequence divergence during vertical transmission of Ty1-copia group retro Transposons within plant lineages has been a major factor in the evolution ofTy1-Copia group Retrotransposons in higher plants.
Abstract: We have used the polymerase chain reaction to isolate fragments of Ty1-copia group retrotransposons from a wide variety of members of the higher plant kingdom 56 out of 57 species tested generate an amplified fragment of the size expected for reverse transcriptase fragments of Ty1-copia group retrotransposons Sequence analysis of subclones shows that the PCR fragments display varying degrees of sequence heterogeneity Sequence heterogeneity therefore seems a general property of Ty1-copia group retrotransposons of higher plants, in contrast to the limited diversity seen in retrotransposons of Saccharomyces cerevisiae and Drosophila melanogaster Phylogenetic analysis of all these sequences shows, with some significant exceptions, that the degree of sequence divergence in the retrotransposon populations between any pair of species is proportional to the evolutionary distance between those species This implies that sequence divergence during vertical transmission of Ty1-copia group retrotransposons within plant lineages has been a major factor in the evolution of Ty1-copia group retrotransposons in higher plants Additionally, we suggest that horizontal transmission of this transposon group between different species has also played a role in this process
TL;DR: The important role of 'multi-site phosphorylation' in signal integration, in which different protein kinases produce additive, synergistic and antagonistic effects on activity by phosphorylating distinct Ser or Thr residues in a single protein is highlighted.
TL;DR: Abnormalities of the p53 gene have been identified in many malignancies, with reports of aberration in over half of colorectal, lung, breast and hepatocellular carcinoma cases.
Abstract: Abnormalities of the p53 gene have been identified in many malignancies, with reports of aberration in over half of colorectal, lung, breast and hepatocellular carcinoma cases. The normal gene acts as a recessive oncogene, while mutations change the apparent function to that of a dominant oncogene.
In this investigation a 3-layered immunoperoxidase technique was applied to routinely fixed and paraffin-embedded tissue sections from 125 gastric carcinomas, using a polyclonal anti-p53 antibody (CM-1).
We found that 57% of these carcinomas expressed high levels of p53 protein (positive nuclear staining). Survival analysis revealed a strong association between p53 status of the tumour and patient survival time after diagnosis (p = 0.02, Mantel-Cox Test); odds ratio of death, 2.09 (95% confidence interval 1.02 to 4.25). The 5-year survival of patients with p53-expressing tumours was 24%, compared with 56% for those non-p53-expressing tumours (the median survival times were 13 and 102 months, respectively).
TL;DR: Some interactions are of biotechnologic importance being relevant to metal removal, including microfossil formation, iron and manganese deposition, silver and uranium mineralisation, as well as resulting in transfer to other organisms via food chains.
Abstract: Metals are directly a n d / o r indirectly involved in all aspects of microbial growth, metabolism and differentiation. Many metals are essential, e.g. K, Na, Mg, Ca, Mn, Fe, Co, Ni, Cu, Zn, Mo, whereas others have no known essential biological function(s), e.g. AI, Ag, Cd, Sn, Au, Sr, Hg, T1, Pb. All these elements can interact with microbial cells and be accumulated as a result of physico-chemical mechanisms and transport systems of varying specificity, independent of, or directly and indirectly dependent on, metabolism [1-4]. Some of these processes are of global importance being components of major biogeochemical cycles, including microfossil formation, iron and manganese deposition, silver and uranium mineralisation, as well as resulting in transfer to other organisms via food chains [2,5-8]. Some interactions are of biotechnologicai importance being relevant to metal removal a n d / o r
TL;DR: These findings are the first to associate anatoxin-a toxicoses with benthic, rather than planktonic, cyanobacteria.
TL;DR: To investigate the mutational spectrum associated with exposure to high levels of radon, exons 5-9 of the p53 tumour suppressor gene and codons 12-13 of the Ki-ras protooncogene were sequenced in 19 lung cancers from uranium miners exposed to radon and tobacco smoke.
TL;DR: RAPDs provide a cost-effective method for the precise and routine evaluation of variability and may be used to identify areas of maximum diversity and are discussed in relation to the exploitation of multi-purpose tree species of the tropics.
Abstract: Gliricidia sepium and G. maculata are multi-purpose leguminous trees native to Central America and Mexico. Research programmes have been initiated to define the native distribution of Gliricidia and sample the spectrum of genetic variation. To date, there has been little systematic assessment of genetic variability in multi-purpose tree species. Accurate estimates of diversity between- and within-populations are considered a prerequisite for the optimization of sampling and breeding strategies. We have used a PCR-based polymorphic assay procedure (RAPDs) to monitor genetic variability in Gliricidia. Extensive genetic variability was detected between species and the variability was partitioned into between- and within-population components. On average, most (60 per cent) of the variation occurs between G. sepium populations but oligonucleotide primers differed in their capacity to detect variability between and within populations. Population-specific genetic markers were identified. RAPDs provide a cost-effective method for the precise and routine evaluation of variability and may be used to identify areas of maximum diversity. The approaches outlined have general applicability to a range of organisms and are discussed in relation to the exploitation of multi-purpose tree species of the tropics.
TL;DR: Laparoscopic cardiomyotomy has the advantage of diminished surgical trauma with accelerated recovery, constitutes definitive therapy comparable to standard myotomy, and by being less disruptive of the lower oesophageal fixation it is prone to precipitate gastro-oesophageals reflux.
Abstract: The cause of the parasympathetic neuropathy in achalasia remains unknown. The treatment of this distressing condition varies from medication with nitrates and calcium-blocking agents, disruption of the lower oesophageal sphincter by balloon dilatation, advocated by gastroenterologists, to surgical intervention. The results of medication with nitrates are indifferent, and the early promise of the value of nifedipine has not be confirmed by prospective studies. Surgical treatment consists of a short 5.0–6.0-cm myotomy which includes the whole extent of the lower oesophageal high pressure zone and adjacent 1.0 cm of stomach. In the only reported prospective study comparing the two techniques, the outcome following myotomy was successful in 95% as compared to 65% after balloon dilatation. Opinions also differ amongst surgeons with regard to the approach: thoracic or abdominal. The disadvantage of open surgical myotomy is the precipitation of gastro-oesophageal reflux, the reported incidence of which varies considerably.
TL;DR: Tetanus toxin and Botulinum neurotoxins implicate a calmodulin-independent locus (or loci) of action common to small- and large-dense-core vesicles and associated with vesicle transport that affects a step common to both exocytotic pathways.
TL;DR: It is shown that p42 MAP kinase phosphorylates recombinant tau and converts it to a form which is similar to PHF tau, with PP2A1 being the most effective form of the enzyme.
TL;DR: It is suggested that the developmental modification of LPG may be important in modulating the binding of promastigotes to receptors in the sandfly midgut and on human macrophages and in increasing the resistance of metacyclic promastIGotes to complement‐mediated lysis.
Abstract: Protozoan parasites of the genus Leishmania produce the novel surface glycoconjugate, lipophosphoglycan (LPG), which is required for parasite infectivity In this study we show that LPG structure is modified during the differentiation of L major promastigotes from a less infectious form in logarithmic growth phase to a highly infectious 'metacyclic' form during stationary growth phase In both stages, the LPGs comprise linear chains of phosphorylated oligosaccharide repeat units which are anchored to the membrane via a glycosyl-phosphatidylinositol glycolipid anchor During metacyclogenesis there is (i) an approximate doubling in the average number of repeat units per molecule from 14 to 30, (ii) a pronounced decrease in the relative abundance of repeat units with side chains of beta Gal or Gal beta 1-3Gal beta 1-, and a corresponding increase in repeat units with either no side chains or with side chains of Arap alpha 1-2 Gal beta 1- and (iii) a decrease in the frequency with which the glycolipid anchor is substituted with a single glucose alpha 1-phosphate residue While the majority of the LPG phosphoglycan chains are capped with the neutral disaccharide, Man alpha 1-2Man, a significant minority of the chains appeared to terminate in non-phosphorylated repeat units and may represent incompletely capped species We suggest that the developmental modification of LPG may be important in modulating the binding of promastigotes to receptors in the sandfly midgut and on human macrophages and in increasing the resistance of metacyclic promastigotes to complement-mediated lysis
TL;DR: In this article, a modified version of the endogenous growth approach is used to show that convergence is occurring but in a non-equalizing manner, with the members of the richer club enjoying a real income per capita which is significantly higher than that enjoyed by those belonging to the poorer club.
Abstract: Recent data indicate a wide disparity in the growth performance of different nations. Such disparities have usually been taken to imply that there is to much catching up or convergence taking place. Using a modified version of the endogenous growth approach, we show that convergence is occurring but in a non-equalizing manner. The world appears to be segmented into two mutually exclusive "convergence clubs" with the members of the richer club enjoying a real income per capita which is significantly higher than that enjoyed by those belonging to the poorer club. Copyright 1992 by Oxford University Press.
TL;DR: MAP kinase kinase is the first established example of a protein kinase that can phosphorylate an exogenous protein on threonine as well as tyrosine residues.
Abstract: A 'MAP kinase activator' was purified several thousand-fold from insulin-stimulated rabbit skeletal muscle, which resembled the 'activator' from nerve growth factor-stimulated PC12 cells in that it could be inactivated by incubation with protein phosphatase 2A, but not by protein tyrosine phosphatases and its apparent molecular mass was 45-50 kDa. In the presence of MgATP, 'MAP kinase activator' converted the normal 'wild-type' 42 kDa MAP kinase from an inactive dephosphorylated form to the fully active diphosphorylated species. Phosphorylation occurred on the same threonine and tyrosine residues which are phosphorylated in vivo in response to growth factors or phorbol esters. A mutant MAP kinase produced by changing a lysine at the active centre to arginine was phosphorylated in an identical manner by the 'MAP kinase activator', but no activity was generated. The results demonstrate that 'MAP kinase activator' is a protein kinase (MAP kinase kinase) and not a protein that stimulates the autophosphorylation of MAP kinase. MAP kinase kinase is the first established example of a protein kinase that can phosphorylate an exogenous protein on threonine as well as tyrosine residues.