Showing papers by "Trinity College, Dublin published in 1983"
TL;DR: Enzyme titration studies and comparisons of the substrate specificities of MAO-A andMAO-B across the brain indicated that dopamine was metabolised by the same MAO active centres as other monoamines.
Abstract: The deamination of dopamine has been studied in seven regions of human brain. Both A and B forms of the enzyme were found to be active towards this substrate. The ratio of activities of MAO-A: MAO-B was found to vary considerably from brain region to brain region, from about 1:1 for the cerebral and cerebellar cortex to about 1:2 for the pons and medulla oblongata. Enzyme titration studies and comparisons of the substrate specificities of MAO-A and MAO-B across the brain indicated that dopamine was metabolised by the same MAO active centres as other monoamines. In the cerebral cortex, the Km values of MAO-A and -B towards dopamine were found to be 210 and 230 microM, respectively, indicating that the relative contributions of these two forms towards the oxidation of this substrate will not be significantly affected by changes in its concentration.
231 citations
TL;DR: In this article, it was shown that every n -homogeneous continuous polynomial on a Banach space E which is weakly continuous on the unit ball of E is also weakly uniformly continuous on E.
148 citations
TL;DR: The hypothesis that the elevated prolactin levels in these patients are indeed linked with emotional stress is supported, as the significant reduction of the Prolactin level, in parallel with decreased anxiety scores following treatment, supports the hypothesis.
105 citations
TL;DR: A DNA sequence encoding Staphylococcus aureus alpha-hemolysin, which had been previously cloned and mapped in Escherichia coli K-12, was introduced into Bacillus subtilis BD170 and several strains of S. aUREus by using plasmid vectors, some of which could replicate in all three organisms.
Abstract: A DNA sequence encoding Staphylococcus aureus alpha-hemolysin, which had been previously cloned and mapped in Escherichia coli K-12, was introduced into Bacillus subtilis BD170 and several strains of S. aureus by using plasmid vectors, some of which could replicate in all three organisms. The determinant was cloned on a 3.3-kilobase pair DNA fragment into B. subtilis by using the vector plasmid pXZ105 to form the hybrid plasmid pXZ111. B. subtilis cells harboring pXZ111 produced large zones of alpha-hemolysis after 18 h of growth at 37 degrees C on rabbit blood agar plates, and alpha-hemolysin activity was detected in supernatants prepared from growing cultures of this strain. The alpha-hemolysin was apparently secreted across the B. subtilis cell envelope. Polypeptides of molecular weights 34,000 and 33,000 were precipitated with anti-alpha-hemolysin serum from lysates prepared from BD170 cells harboring pXZ111. A hybrid replicon which could replicate in both E. coli and S. aureus was constructed in E. coli by ligating a HindIII fragment encoding the replication functions and chloramphenicol resistance genes of S. aureus plasmid pCW59 to the pBR322 alpha-hemolysin hybrid plasmid pDU1150. The DNA of this plasmid, pDU1212, was prepared in E. coli and used to transform protoplasts prepared from a non-alpha-hemolytic, nonrestricting strain of S. aureus RN4220. Some of the transformants contained plasmids which had suffered extensive deletions. Some plasmids, however, were transformed intact into RN4220. Such plasmids were subsequently maintained in a stable manner. pDU1212 DNA was prepared from RN4220 and transformed into alpha-hemolytic S. aureus 8325-4 and two mutant derivatives defective in alpha-hemolysin synthesis. All three strains expressed alpha-hemolysin when harboring pDU1212. Images
97 citations
TL;DR: A novel dye-staining method has been developed to detect β-glucanase activity in colonies on agar plates and directs the synthesis in E. coli of a β- GLUCanase which specifically degrades barley glucan and lichenan.
93 citations
TL;DR: It is concluded that these plants provide the earliest record of erect fertile land plants of possible pteridophyte affinity and sedimentological and palaeontological studies of the region provide little direct evidence for the habitats of the plants which are considered to have been terrestrial.
89 citations
TL;DR: In this article, the problem of finding a Wahlquist-Estabrook prolongation structure for a given (system of) nonlinear evolution equation(s) is investigated. But the complexity of the problem is not discussed.
Abstract: We look closely at the process of finding a Wahlquist-Estabrook prolongation structure for a given (system of) nonlinear evolution equation(s). There are two main steps in this calculation: the first, to reduce the problem to the investigation of a finitely generated, free Lie algebra with constraints; the second, to find a finite-dimensional linear representation of these generators. We discuss some of the difficulties that arise in this calculation. For quasi-polynomial flows (defined later) we give an algorithm for the first step. We do not totally solve the problems of the second step, but do give an algebraic framework and a number of techniques that are quite generally applicable. We illustrate these methods with many examples, several of which are new.
76 citations
TL;DR: In 'ex vivo' studies, the inhibitory activity of CGP 11305 A was not lost by dilution or dialysis of homogenates from pretreated animals and the inhibitor could not be displaced by 5-HT, indicating an irreversible interaction.
74 citations
TL;DR: Evidence is presented that the cloned fragment codes for a B. licheniformis heat-stable alpha-amylase with a temperature optimum of 93 degrees C and the foreign gene is expressed efficiently in B. subtilis and is stably maintained.
71 citations
TL;DR: The Burren is a plateau karst on the west coast of Ireland as mentioned in this paper, characterized by thin soils, patchy vegetation and large areas of bare rock, supposedly a legacy of glacial erosion.
60 citations
TL;DR: A hemolysin determinant was cloned from Pseudomonas aeruginosa PA103 by inserting Sau3a-generated DNA fragments between the BamHI sites of the lambda replacement vector WL47 to generate the recombinant plasmid pKC95.
Abstract: A hemolysin determinant was cloned from Pseudomonas aeruginosa PA103 by inserting Sau3a-generated DNA fragments between the BamHI sites of the lambda replacement vector WL47.1. A 9.5-kilobase HindIII fragment encoding the hemolysin was subcloned from this phage and inserted into the plasmid vector pHC79 to generate the recombinant plasmid pKC95. Escherichia coli K-12 strains harboring pKC95 exhibited zones of hemolysis after several days of growth on blood agar plates. Hemolysis was shown to be due to phospholipase C activity by using the chromogenic substrate p-nitrophenylphosphorylcholine. Deletion mutants of pKC95 were isolated, and polypeptides expressed from these plasmids were examined by using the E. coli minicell system. A polypeptide of 78,000 daltons was associated with phospholipase C activity. The hemolytic activity was cell associated when expressed in E. coli.
TL;DR: In this article, the Kramers equation for one dimensional motion of brownian particles in a multiwell cosine potential is solved by a series expansion method followed by numerical solution of the resulting set of linear differential equations to obtain angular velocity and orientational autocorrelation functions (a.c.f.s) in the Laplace domain.
Abstract: The Kramers equation for one dimensional motion of brownian particles in a multiwell cosine potential is solved by a series expansion method followed by numerical solution of the resulting set of linear differential equations to obtain angular velocity and orientational autocorrelation functions (a.c.f.s) in the Laplace domain. The former, inverted by analytic function fitting, take the correct forms at zero and large (harmonic limit) potentials and intermediate behaviours compare well with those found using other numerical techniques. Solutions evaluated using delta function initial conditions are of interest in the study of pendula or of chemical dissociation, while solutions evaluated under equilibrium initial conditions and with imaginary Laplace variable iw are important in dielectric spectroscopy. Application of the theory both to superionic conductivity and dielectric-far-I.R. absorption of rotator phases and liquids is demonstrated.
TL;DR: A fragment of Staphylococcus aureus DNA encoding the alpha-hemolysin determinant was cloned from strain Wood 46 by inserting Sau3A-generated genomic DNA fragments between the BamHI sites of the lambda replacement vector L47.
Abstract: A fragment of Staphylococcus aureus DNA encoding the alpha-hemolysin determinant was cloned from strain Wood 46 by inserting Sau3A-generated genomic DNA fragments between the BamHI sites of the lambda replacement vector L47.1. Phages expressing alpha-hemolysin were detected by overlaying plaques formed from several thousand independent recombinant phage with erythrocytes and looking for zones of hemolysis. One phage expressing alpha-hemolysin was purified and named lambda w alpha 3. This was subsequently shown to contain a 10.2-kilobase pair insert of S. aureus DNA. A 7.6-kilobase pair HindIII fragment encoding the alpha-hemolysin was subcloned from lambda w alpha 3 into the plasmid vector pACYC184 to form the hybrid plasmid pDU1148. Escherichia coli K-12 cells harboring pDU1148 synthesized a low level of alpha-hemolysin which remained associated with the cells and was not secreted into culture supernatants. When the same strain was stabbed onto blood agar plates, no zones of hemolysis were detected after overnight growth at 37 degrees C but hemolysis developed if the plates were left at room temperature for 48 h. By introducing specific deletions or Tn5 insertions into plasmid pDU1148, the alpha-hemolysin gene was mapped to a region within a 3.3-kilobase pair EcoRI-HindIII fragment which was subcloned onto the vector plasmid pBR322. A specific enzyme-linked immunosorbent assay with peroxidase-labeled rabbit anti-alpha-hemolysin antibodies was used to measure the levels of alpha-hemolysin antigen expressed in E. coli K-12 cells harboring pDU1148 or a variety of pDU1148::Tn5 and pDU1148 deletion mutants.
TL;DR: Affinity precipitation, a novel technique closely related to immunoprecipitation and affinity chromatography, has been evaluated in systems comprised of dehydrogenases and a bifunctional NAD derivative, Bis-NAD, and the yield and purity of the enzyme and the general properties are considered very satisfactory.
TL;DR: In this paper, a simple model of a small open economy which is open to both commodity trade and foreign investment of a sector-specific kind, and which exhibits the phenomenon of crosshauling, or reverse flows of internationally mobile capital in two different sectors.
TL;DR: In this article, the potential of spray drying to produce high energy drug forms was investigated using phenobarbitone and hydroflumethiazide, and an amorphous product was obtained on spray-drying with 10% PVP.
Abstract: The potential of spray drying to produce high energy drug forms was investigated using phenobarbitone and hydroflumethiazide. Whereas commercial phenobarbitone is normally Form II, the product produced by spray drying had a large specific surface area (17m 2/g) and physical properties similar to Form III. The apparent solubility of this spray dried material was 25% greater than that of Form II. An amorphous product was obtained on spray drying phenobarbitone with 10% PVP. Spray dried hydroflumethiazide was amorphous and had an apparent solubility 1.61 times that of the crystalline form. Co-spray drying hydroflumethiazide with 10% PVP also produced an amorphous system. Differential scanning calorimetry suggested that the system contained both amorphous drug and an amorphous drug-PVP complex. The product had an apparent solubility 2.5 times that of the pure crystalline drug. Spray drying, either in the presence or absence of excipients, can result in the formation of high energy drug polymorphs or a...
TL;DR: A difference in biochemical composition between the sexes was noted in pre-spawning months (June to early September) and females showed an increase in the amount of lipid while males had a larger proportion of protein; no differences were apparent in the carbohydrate content.
TL;DR: In this article, a theory of the overall rates and molecular weights in slowly-initiated, nonterminated polymerizations is developed for cases of complex initiation of alkyl cyanoacrylates by tertiary amines.
Abstract: A theory of the overall rates and molecular weights in slowly-initiated, non-terminated polymerizations is developed for cases of complex initiation of alkyl cyanoacrylates by tertiary amines Results with butyl cyanoacrylate (BCA) in the solvent THF, and five different amines (chiefly pyridine and derivatives) show widely differing overall rates The theory, with the aid of previously determined initiation rate constants, permits the same value for the propagation rate constant (kp) to be derived in all cases, corroborated by values derived from the simpler overall kinetics of polymerisation initiated by Ph3P The rate constant kp shows very slight temperature dependence, less than one order of magnitude between 20 and −80°C
TL;DR: E. coli mutants defective in the synthesis of murein lipoprotein or the major outer membrane polypeptide OmpA were found to express normal amounts of K 88ac antigen on the cell surface, whereas expression of the K88ac antigen was greatly reduced in perA mutants.
Abstract: Escherichia coli K-12 minicells, harboring recombinant plasmids encoding polypeptides involved in the expression of K88ac adhesion pili on the bacterial cell surface, were labeled with [35S]methionine and fractionated by a variety of techniques. A 70,000-dalton polypeptide, the product of the K88ac adhesion cistron adhA, was primarily located in the outer membrane of minicells, although it was less clearly associated with this membrane than the classical outer membrane proteins OmpA and matrix protein. Two polypeptides of molecular weights 26,000 and 17,000 (the products of adhB and adhC, respectively) were located in significant amounts in the periplasmic space. The 29,000-dalton polypeptide was shown to be processed in E. coli minicells. The 23.500-dalton K88ac pilus subunit (the product of adhD) was detected in both inner and outer membrane fractions. E. coli mutants defective in the synthesis of murein lipoprotein or the major outer membrane polypeptide OmpA were found to express normal amounts of K88ac antigen on the cell surface, whereas expression of the K88ac antigen was greatly reduced in perA mutants. The possible functions of the adh cistron products are discussed.
TL;DR: In this article, a detailed theory is proposed and used to evaluate the composite initiation rate constants over the temperature range 20°C to −80°C, and the influence of steric factors on the initiation by pyridine, picolines and lutidine is exemplified and discussed.
Abstract: Polymerizations of butyl and ethyl cyanoacrylates, in the solvent THF, initiated by pyridine and other tertiary amines, are inhibited by strong acids, which cause well-defined inhibition periods (ti) proportional to the concentration of acid added, but irrespective of its nature The temperature and monomer concentration dependence of ti indicate that chain-initiation is a composite sequence involving two or three successive additions of monomer A detailed theory is proposed and used to evaluate the composite initiation rate constants over the temperature range 20°C to −80°C The influence of steric factors on the initiation by pyridine, picolines and lutidine is exemplified and discussed
TL;DR: This article found that Irish households before the First World War were uncomfortably large, and their bulges appeared in the wrong places, indicating a more fundamental divergence between the underlying structures of English and Irish families.
Abstract: It has lately become commonplace to suspect that most household and family structures in history were much the same. Under the pugnacious influence of the Cambridge Group for the History of Population and Social Structure, historians have grown wary of drawing attention to apparently abnormal household structures, and perhaps weary of reiterating the predominance in northwestern European societies of the simple or nuclear family household. Ireland, however, was not easily squeezed into the Cambridge standard model as generated for preindustrial England. Not only were Irish households before the First World War uncomfortably large, but their bulges appeared in the wrong places. Admittedly these divergences were not great; yet to students following the path of Conrad M. Arensberg and Solon T. Kimball they betokened a more fundamental divergence between the underlying structures of English and Irish families.
TL;DR: Findings indicate that direct virus-induced injury to oligodendrocytes has a major role in the initiation of inflammation and demyelination in this model system.
Abstract: Intraperitoneal inoculation with the M9 mutant of Semliki Forest virus caused focal demyelinating encephalomyelitis in weanling BALB/c and C57BL/6 mice. Demyelination was more severe in BALB/c than in C57BL/6 mice. Virus particles were seen in oligodendrocytes in areas of myelin vacuolation 5 and 7 days post inoculation (DPI). Oligodendrocytes containing virus in BALB/c mice showed hypertrophy and vacuolar degeneration. There was a mononuclear cell infiltrate and lymphocytes and necrotic cells were present in vacuoles in myelin sheaths. Demyelinating plaques containing macrophages laden with myelin debris were most prominent 14 DPI when virus was cleared from the brain. Remyelination of the central type occurred 28 DPI in BALB/c mice. These findings indicate that direct virus-induced injury to oligodendrocytes has a major role in the initiation of inflammation and demyelination in this model system.
TL;DR: Low-temperature electron spin resonance spectroscopy has been used to study the biophysical properties of succinate dehydrogenase from the gram-positive bacterium Micrococcus luteus, and it is proposed that under saturating conditions the spin-lattice relaxation of the [2Fe-2S] cluster S-1 is enhanced by centre S-3 between the potential range +10-+70 mV and by an ESR-silent centre, termed centre S
Abstract: Low-temperature electron spin resonance spectroscopy has been used to study the biophysical properties of succinate dehydrogenase from the gram-positive bacterium Micrococcus luteus The paramagnetic redox centres of the enzyme were identified in a succinate-dehydrogenase--antigen complex, which had been purified with the aid of monospecific serum from membranes solubilized with Triton X-100 The centres were characterized in further detail using the membrane-bound and Triton-solubilized forms of the enzyme These studies distinguished two types of iron-sulphur centres, viz a [4Fe-4S]3+ cluster displaying a narrow signal at g = 201 in the oxidized state (conventionally termed centre S-3) and a [2Fe-2S )0 cluster with an axial signal at g = 203 and 193 in the reduced state (conventionally termed centre S-1) Centre S-3 had a mid-point redox potential of +10 mV, a comparatively low value for this type of cluster The behaviour of the g = 193 signal of centre S-1 was a complex function of the redox potential, microwave power and temperature of measurement When measured at low power (ie non-saturating conditions), the intensities observed for the g = 193 signal poised at various critical potentials in the redox titration were similar However, the corresponding intensities differed markedly at high power, where conditions were saturating It is proposed that under saturating conditions the spin-lattice relaxation of the [2Fe-2S] cluster S-1 (mid-point potential +70 mV) is enhanced by centre S-3 between the potential range +10-+70 mV and by an ESR-silent centre, termed centre S-2, with a mid-point potential of -295 mV
TL;DR: In this paper, a strong causal relationship between the sequence of tectonic events and the regional facies associations is demonstrated, and the patterns of megafacies from Upper Devonian to Westphalian are described and discussed in this context.
TL;DR: It is argued that the results suggest that the way the procurement cost of food is related to both the frequency and size of meals is due to a direct but independent effect of the cost on both meal size and latency to initiate eating.
TL;DR: A large number of Staphylococcus aureus strains resistant to gentamicin, methicillin and other antibiotics, isolated in several Dublin hospitals during a 4-year period, were screened for plasmid DNA.
Abstract: A large number of Staphylococcus aureus strains resistant to gentamicin, methicillin and other antibiotics, isolated in several Dublin hospitals during a 4-year period, were screened for plasmid DNA. Isolates assigned to four principal phage groups showed uniform plasmid profiles. A plasmid of mol. wt 21.0 x 106 encoding penicillin resistance was present in all isolates screened. A tetracycline resistance plasmid of mol. wt 24.0 x 106 was present in 40% of isolates of phage types 90 and 5/47/54/84/85 whereas a plasmid of mol. wt 3.0 x 106 was responsible for tetracycline resistance in isolates of phage types 77 and 85. Aminoglycoside, methicillin and erythromycin resistances were apparently not encoded on plasmids. Gentamicin resistance was transduced at low frequency between several strains of S. aureus and the resistance phenotype was due, in part at least, to the production of an inactivating enzyme.
TL;DR: There was a close association between the onset of quadriceps and hamstrings activity both in the normal and resistance paces, and changes observed in knee angular velocity upon application of the resistance indicate tight control of angular velocity patterns.
Abstract: Muscle activation patterns of the quadriceps and hamstrings were studied in normal human subjects walking at comfortable speed on a treadmill. In addition knee angular velocity patterns and swing and stance phases of the step cycle were recorded. Data were collected from normal paces and from paces in which a momentary unexpected resistance was applied to the leg during swing. The application of the resistance caused an advance in the onset of both quadriceps and hamstrings activity. The latency of the onset of activity following the resistance in the quadriceps was 78.2±26.4 ms and this was considered to indicate a long latency stretch reflex. There was a close association between the onset of quadriceps and hamstrings activity both in the normal and resistance paces. The changes observed in knee angular velocity upon application of the resistance indicate tight control of angular velocity patterns. The results have important implications regarding neural control of muscle during purposive movement and the regulation of sensitivity of muscle receptors during such movements, especially during the periods when the muscle is normally inactive.
TL;DR: In this article, the authors identify hydrogarnet Ca2AlFeO5, steam cured at 72 C, using X-ray diffraction and Mossbauer spectroscopy.
TL;DR: Although carriage rates did not change, there was a trend towards multiple resistance with increasing hospital exposure and gentamicin resistance in Staphylococcus albus showed a similar trend.
TL;DR: By constructing specific deletion and insertion mutants of pMK005, a fifth adhesion cistron, tentatively named adhE, was identified and mapped at the proximal end of the K88ac determinant, providing evidence that a single transcription unit, initiating at promoter P1 of pBR322, may be involved in the expression of theK88ac antigen.
Abstract: The determinant for the K88ac adherence antigen of porcine enterotoxigenic Escherichia coli has been cloned previously onto the vector plasmid pBR322 to form the K88ac-pBR322 hybrid plasmid pMK005 (M. Kehoe et al., Nature [London] 291:122-126). Further studies on the expression of the K88ac antigen from pMK005 are presented in this paper. Expression was found to be dependent mainly on the P1 promoter of the pBR322 vector. The natural K88ac promoter was apparently not cloned from the original parental K88ac plasmid. The P1 promoter was deleted and replaced by a DNA sequence encoding the promoter-operator region of the E. coli tryptophan (Trp) operon. Cells harboring the Trp-pMK005 hybrid plasmid expressed high levels of K88ac antigen when the Trp promoter was repressed. If the promoter was derepressed either by growing the cells in low concentrations of tryptophan or in the presence of indole acrylic acid, growth of the cells harboring the Trp-pMK005 hybrid plasmid was inhibited. A quantitative assay was used to measure the levels of K88ac antigen expressed by cells harboring different pMK005::Tn5 plasmids. All cells were found to express a reduced level of K88ac antigen, providing evidence that a single transcription unit, initiating at promoter P1 of pBR322, may be involved in the expression of the K88ac antigen. By constructing specific deletion and insertion mutants of pMK005, a fifth adhesion cistron, tentatively named adhE, was identified and mapped at the proximal end of the K88ac determinant. Although the cistron is required for high-level expression of K88ac surface-associated fimbriae, as yet no gene product has been assigned to adhE.