bluuebunny/crossref_metadata_2025 huggingface dataset:
Metamorphosis of human lumbar vertebrae induced by VEPTR growth modulation and stress shielding
Authors: Hasler Carol C. , Studer Daniel , Büchler Philippe
Published: August 2015

Introduction

Distraction-based spinal growth modulation by growing rods or vertical expandable prosthetic titanium ribs (VEPTRs) is the mainstay of instrumented operative strategies to correct early onset spinal deformities. In order to objectify the benefits, it has become common sense to measure the gain in spine height by assessing T1-S1 distance on anteroposterior (AP) radiographs. However, by ignoring growth changes on vertebral levels and by limiting measurement to one plane, valuable data is missed regarding the three-dimensional (3D) effects of growth modulation. This information might be interesting when it comes to final fusion or, even more so, when the protective growing implants are removed and the spine re-exposed to physiologic forces at the end of growth.

Methods

The goal of this retrospective radiographic study was to assess the growth modulating impact of year-long, distraction-based VEPTR treatment on the morphology of single vertebral bodies. We digitally measured lumbar vertebral body height (VBH) and upper endplate depth (VBD) at the time of the index procedure and at follow-up in nine patients with rib-to-ileum constructs (G1) spanning an anatomically normal lumbar spine. Nine patients with congenital thoracic scoliosis and VEPTR rib-to-rib constructs, but uninstrumented lumbar spines, served as controls (G2). All had undergone more than eight half-yearly VEPTR expansions. A Wilcoxon signed-rank test was used for statistical comparison of initial and follow-up VBH, VBD and height/depth (H/D) ratio (significance level 0.05).

Results

The average age was 7.1 years (G1) and 5.2 year (G2, p > 0.05) at initial surgery; the average overall follow-up time was 5.5 years ( p = 1). In both groups, VBH increased significantly without a significant intergroup difference. Group 1 did not show significant growth in depth, whereas VBD increased significantly in the control group. As a consequence, the H/D ratio increased significantly in group 1 whereas it remained unchanged in group 2. The growth rate for height in mm/year was 1.4 (group 1) and 1.1 (group 2, p = 0.45), and for depth, it was −0.3 and 1.1 ( p < 0.05), respectively.

Conclusions

VEPTR growth modulating treatment alters the geometry of vertebral bodies by increasing the H/D ratio. We hypothesize that the implant-related deprivation from axial loads (stress-shielding) impairs anteroposterior growth. The biomechanical consequence of such slender vertebrae when exposed to unprotected loads in case of definitive VEPTR removal at the end of growth is uncertain.
Eating Disorder Examination Questionnaire (EDE-Q): norms for female university students attending a university primary health care service in Ireland
Authors: Keane S. , Clarke M. , McGrath D. , Farrelly N. , MacHale S.
Published: August 2015

Objectives

The Eating Disorder Examination Questionnaire (EDE-Q) is a self-report questionnaire that is used to identify probable cases of eating disorders. Norms are needed for interpretation of scores. The aim of this study is to establish norms for the EDE-Q among female university students attending a university primary health care service in Ireland and to present prevalence of key eating disorder behaviours.

Methods

The EDE-Q was administered to a consecutive sample of 200 female students aged 18–30 years attending a university primary health care service.

Results

The mean global EDE-Q score was 1.51 (s.d.=1.28). There was a positive association between body mass index and the global EDE-Q score; 5.8% of the sample scored in the clinically significant range on the global EDE-Q score.

Conclusions

This study presents normative EDE-Q data for an Irish female university sample. These norms may inform clinicians and/or researchers in the evaluation of EDE-Q scores in Irish female university students
Sounding the field: recent works in sound studies
Authors: Boon Tim
Published: August 2015

For sound studies, the publication of a 593-page handbook, not to mention the establishment of at least one society – the European Sound Studies Association – might seem to signify the emergence of a new academic discipline. Certainly, the books under consideration here, alongside many others, testify to an intensification of concern with the aural dimensions of culture. Some of this work comes from HPS and STS, some from musicology and cultural studies. But all of it should concern members of our disciplines, as it represents a long-overdue foregrounding of the aural in how we think about the intersections of science, technology and culture.
Stochastic Models for Chladni Figures
Authors: Arango Jaime , Reyes Carlos
Published: August 2015

Chladni figures are formed when particles scattered across a plate move due to an external harmonic force resonating with one of the natural frequencies of the plate. Chladni figures are precisely the nodal set of the vibrational mode corresponding to the frequency resonating with the external force. We propose a plausible model for the movement of the particles that explains the formation of Chladni figures in terms of the stochastic stability of the equilibrium solutions of stochastic differential equations.
Simulation as a tool to improve wave heating in fusion plasmas
Authors: Heuraux S. , da Silva F. , Ribeiro T. , Despres B. , Campos Pinto M. , Jacquot J. , Faudot E. , Wengerowsky S. , Colas L. , Lu L.
Published: August 2015

Firstly, a brief overview will be given on different models that are able to describe the behaviour of wave propagation as a function of specific frequency ranges. Each range corresponds to different heating systems, namely, 20–100 MHz for the ion cyclotron resonant heating, 2–20 GHz for lower-hybrid heating or current drive, and 100–250 GHz for electron cyclotron resonant heating or current drive systems. The specification of every system will be explained in detail, including the typical set of equations and the assumptions needed to describe the properties of these heating or current drive systems, as well as their specific domains of validity. In these descriptions, special attention will be paid to the boundary conditions. A review of specific physical problems associated with the wave heating systems will also be provided. The review will detail the role of simulation in answering questions that arise from experiments on magnetized plasma devices devoted to fusion. A few examples that will be covered are the impact of edge turbulence on wave propagation and its consequences on heating system performance, the effects of fast particles and ponderomotive effects, among others. A study that is more focused on radio-frequency sheath effects will also be discussed. It shows that such simulations require very sophisticated tools to gain a partial understanding of the observations undertaken in dedicated experiments. To conclude this review, an overview will be given about the requirements and progress necessary to obtain relevant predictive simulation tools able to describe the wave heating systems used in fusion devices.
Quantitative activation-induced manganese-enhanced MRI reveals severity of Parkinson’s disease in mice
Authors: Kikuta Satomi , Nakamura Yukiyo , Yamamura Yukio , Tamura Atsushi , Homma Noriyasu , Yanagawa Yuchio , Tamura Hajime , Kasahara Jiro , Osanai Makoto
Published: August 2015

We demonstrate that activation-induced manganese-enhanced magnetic resonance imaging with quantitative determination of the longitudinal relaxation time (qAIM-MRI) reveals the severity of Parkinson’s disease (PD) in mice. We first show that manganese ion-accumulation depends on neuronal activity. A highly active region was then observed by qAIM-MRI in the caudate-putamen in PD-model mice that was significantly correlated to the severity of PD, suggesting its involvement in the expression of PD symptoms.
Quantum Phase Coherence in Mesoscopic Transport Devices with Two-Particle Interaction
Authors: Wang Zhimei , Guo Xiaofang , Xue Haibin , Xue Naitao , Liang J.-Q.
Published: August 2015

In this paper we demonstrate a new type of quantum phase coherence (QPC), which is generated by the two-body interaction. This conclusion is based on quantum master equation analysis for the full counting statistics of electron transport through two parallel quantum-dots with antiparallel magnetic fluxes in order to eliminate the Aharonov-Bohm interference of either single-particle or non-interacting two-particle wave functions. The interacting two-particle QPC is realized by the flux-dependent oscillation of the zero-frequency cumulants including the shot noise and skewness with a characteristic period. The accurately quantized peaks of cumulant spectrum may have technical applications to probe the two-body Coulomb interaction.
A Validated Phenotyping Algorithm for Genetic Association Studies in Age-related Macular Degeneration
Authors: Simonett Joseph M. , Sohrab Mahsa A. , Pacheco Jennifer , Armstrong Loren L. , Rzhetskaya Margarita , Smith Maureen , Hayes M. Geoffrey , Fawzi Amani A.
Published: August 2015

Age-related macular degeneration (AMD), a multifactorial, neurodegenerative disease, is a leading cause of vision loss. With the rapid advancement of DNA sequencing technologies, many AMD-associated genetic polymorphisms have been identified. Currently, the most time consuming steps of these studies are patient recruitment and phenotyping. In this study, we describe the development of an automated algorithm to identify neovascular (wet) AMD, non-neovascular (dry) AMD and control subjects using electronic medical record (EMR)-based criteria. Positive predictive value (91.7%) and negative predictive value (97.5%) were calculated using expert chart review as the gold standard to assess algorithm performance. We applied the algorithm to an EMR-linked DNA bio-repository to study previously identified AMD-associated single nucleotide polymorphisms (SNPs), using case/control status determined by the algorithm. Risk alleles of three SNPs, rs1061170 (CFH), rs1410996 (CFH) and rs10490924 (ARMS2) were found to be significantly associated with the AMD case/control status as defined by the algorithm. With the rapid growth of EMR-linked DNA biorepositories, patient selection algorithms can greatly increase the efficiency of genetic association study. We have found that stepwise validation of such an algorithm can result in reliable cohort selection and, when coupled within an EMR-linked DNA biorepository, replicates previously published AMD-associated SNPs.
Paclitaxel-induced lung injury and its amelioration by parecoxib sodium
Authors: Liu Wen-jie , Zhong Zhong-jian , Cao Long-hui , Li Hui-ting , Zhang Tian-hua , Lin Wen-qian
Published: August 2015

To investigate the mechanism of paclitaxel-induced lung injury and its amelioration by parecoxib sodium. In this study, rats were randomly divided into: the control group (Con); the paclitaxel chemotherapy group (Pac); the paclitaxel+ parecoxib sodium intervention group (Pac + Pare); and the parecoxib sodium group (Pare). We observed changes in alveolar ventilation function, alveolar-capillary membrane permeability, lung tissue pathology and measured the levels of inflammatory cytokines and cyclooxygenase-2 (Cox-2) in lung tissue, the expression of tight junction proteins (Zo-1 and Claudin-4). Compared with the Con group, the lung tissue of the Pac group showed significantly increased expression of Cox-2 protein (p < 0.01), significant lung tissue inflammatory changes, significantly increased expression of inflammatory cytokines, decreased expression of Zo-1 and Claudin-4 proteins (p < 0.01), increased alveolar-capillary membrane permeability (p < 0.01) and reduced ventilation function (p < 0.01). Notably, in Pac + Pare group, intraperitoneal injection of parecoxib sodium led to decreased Cox-2 and ICAM-1 levels and reduced inflammatory responses, the recovered expression of Zo-1 and Claudin-4, reduced level of indicators reflecting the high permeability state and close-to-normal levels of ventilation function. Intervention by the Cox-2-specific inhibitor parecoxib sodium can block this damage.
Electron Holography of Nanostructured Materials
Authors: Dunin-Borkowski Rafal E , Kasama Takeshi , Harrison Richard J
Published: August 2015

This chapter contains an overview of the theory and applications of electron holography, a powerful technique that allows the phase shift of a high-energy electron wave that has passed through a thin sample to be measured in the transmission electron microscope (TEM). The recorded phase shift is sensitive to both the magnetic induction and the electrostatic potential within and around the specimen. The chapter begins with the theoretical basis of the off-axis mode of electron holography in the TEM. Selected applications of the technique for the quantitative measurement of magnetic fields and electrostatic potentials in nanoscale materials and devices are then described. The in situ application of external stimuli, including applied voltage, magnetic field, temperature and a gas reaction environment during the acquisition of electron holograms, is discussed. High-resolution electron holography and alternative modes of electron holography are described briefly and possible future developments and applications of the technique are outlined.
Visible and near-infrared upconversion photoluminescence in lanthanide-doped KLu3F10 nanoparticles
Authors: Bian Wenjuan , Wang Ting , Guo Yanmei , Yu Xue , Xu Xuhui , Qiu Jianbei
Published: August 2015

Upconversion (UC) photoluminescent nanocrystals of Ln3+-doped KLu3F10 have been synthesized via a facile and environmentally-friendly hydrothermal route.
Electrochemical reduction of CO2 to ethylene glycol on imidazolium ion-terminated self-assembly monolayer-modified Au electrodes in an aqueous solution
Authors: Tamura Jun , Ono Akihiko , Sugano Yoshitsune , Huang Chingchun , Nishizawa Hideyuki , Mikoshiba Satoshi
Published: August 2015

The IL-based SAMs-modified Au electrodes have high selectivity of products from CO2 to ethylene glycol (a maximum of 87%).
Fabrication of silver-decorated sulfonated polystyrene microspheres for surface-enhanced Raman scattering and antibacterial applications
Authors: Zhao Kai , Zhao Jie , Wu Chengjiao , Zhang Shengwen , Deng Ziwei , Hu Xiaoxi , Chen Mingli , Peng Bo
Published: August 2015

A facile approach was presented to prepare SPS@Ag composite microspheres with surface-enhanced Raman scattering properties and enhanced antibacterial activities.
Magnetic macro-initiators
Authors: Miller K. R. , Soucek M. D.
Published: August 2015

Macro-initiators were prepared using three magnetic nanoparticles, Fe3O4, FeCo, or Co.
Effects of sodium and potassium ions on oxidative phosphorylation in relation to respiratory control by a cell-membrane adenosine triphosphatase
Authors: Blond DM , Whittam R
Published: August 2015

1. A study has been made of the oxygen consumption of kidney homogenates in relation to the ADP concentration as regulated by the cell-membrane adenosine triphosphatase. Stimulation of this enzymic activity by Na(+) and K(+) caused parallel increases in oxygen consumption and ADP concentration. Similarly, inhibition with ouabain caused a parallel fall. The membrane adenosine triphosphatase concerned in active transport therefore appears to regulate respiration through its control of ADP concentration. 2. The respiration of homogenates and mitochondria was also stimulated by K(+) in a way independent of adenosine-triphosphatase activity. It was shown that K(+) facilitates oxidative phosphorylation and the respiratory response to ADP. A K(+) concentration of 25-50mm was needed for maximum oxidative phosphorylation in the presence of physiological concentration of Na(+). Na(+) counteracted K(+) in the effects on mitochondria. It is concluded that K(+) regulates cellular respiration at two structures, one directly in mitochondria, and the second indirectly through control of ADP production at the cell membrane.
Production and purification of bacilysin
Authors: Rogers HJ , Newton GGF , Abraham EP
Published: August 2015

1. Bacilysin, a hydrophilic substance formed by certain aerobic spore-forming bacteria that causes lysis in cultures of growing staphylococci, has been produced in aerated cultures of a strain of Bacillus subtilis (A14). A chemically defined medium was used, which contained glucose, Czapek-Dox salts and ferric iron. Production of bacilysin occurred, after a lag, while the culture was still undergoing rapid growth. 2. Bacilysin was adsorbed from the culture medium on Zeo-Karb 225 (SR5) (H(+) form) and eluted with aqueous pyridine. The crude material was purified by chromatography in pyridine-acetate buffers on columns of Dowex 50 (X2) and Dowex 50 (X8) respectively and by chromatography in aq. 70% (v/v) propan-2-ol on Sephadex G-25. 3. Purified bacilysin behaved as a single ninhydrin-positive substance when subjected to chromatography on paper in butan-1-ol-acetic acid-water and to electrophoresis on paper at pH4.5 or pH1.8. At pH4.5 the substance behaved as though it had no net change and at pH1.8 it migrated towards the cathode.
A study of the Crabtree effect in Novikoff ascites-hepatoma cells
Authors: Nigam V N
Published: August 2015

Novikoff ascites-hepatoma cells show no Crabtree effect on the addition of glucose to tumour-cell suspensions, and convert a significant part of the added glucose into glycogen. Treatment of the cells with 2-deoxyglucose or glucose in the presence of iodoacetate inhibits respiration and decreases glycogen synthesis from glucose. Short-term experiments indicate a slight inhibition of glucose uptake for a brief period, due either to ATP accumulation in the mitochondria or to glucose 6-phosphate-mediated inhibition of hexokinase. Utilization of glucose metabolites and ATP for glycogen synthesis appears to remove inhibition of glucose uptake, and perhaps accounts for the absence of respiratory inhibition, by relieving a deficiency of ADP for the mitochondria. Decreased respiration in the presence of 2-deoxyglucose or glucose in the presence of iodoacetate could be due to the change in mitochondrial structure or permeability, caused by the significant loss of adenine nucleotides.
Mode of interaction of purine nucleotides and amino acids with glutamate dehydrogenase
Authors: Hershko A , Kindler SH
Published: August 2015

1. The mode of action of purine nucleotides and amino acids on the activity of ox-liver glutamate dehydrogenase was investigated. 2. The addition of two chemically unrelated activators, at concentrations below saturation levels, enhanced the enzyme activity much more than a twofold concentration of each one separately. No such synergistic activation was observed when a combination of two members of the same group was tested. 3. With saturating concentrations of the activators, the increase in enzymic activity produced by a pair of chemically related effectors was either identical with or even below that achieved by the more active effector. However, the combination of two unrelated activators, at saturating amounts, still yielded a higher enzyme activity than with each one singly. 4. Unlike ADP, l-leucine was incapable of overcoming completely the inhibition produced by GTP. 5. It is suggested that purine nucleotides and amino acids bind to separate group-specific allosteric sites of this enzyme. 6. The possible physiological significance of these findings with regard to the regulation of the cellular functions of this enzyme is discussed.
Thermal stability of ribosomal ribonucleic acid from baby hamster kidney cells
Authors: Martin SJ
Published: August 2015

1. RNA has been prepared from baby hamster kidney cells by extraction with a phenol-EDTA mixture and further purified by passing through a column of Sephadex G-25 that had been equilibrated with water. 2. Aging of the total RNA extracts at 4 degrees or heating at 95 degrees followed by rapid cooling caused a conversion of 28s RNA into material sedimenting in sucrose gradients at approx. 18s. 3. When heated RNA was re-extracted with phenol the sedimentation profile was not returned to that of the unheated RNA. 4. The 28s and 18s RNA fractions were collected separately from sucrose gradients by precipitation with 2vol. of ethanol and passed through a Sephadex G-25 column equilibrated with water. 5. Heat treatment of purified 28s RNA at 95 degrees caused the sedimentation coefficient to increase to approx. 40s, whereas similar treatment of 18s RNA caused no significant increase. If the RNA was heated before the Sephadex G-25 treatment the sedimentation coefficient of the 28s and 18s RNA decreased to approx. 12s and 8s. 6. Heating mixtures of purified 28s and 18s RNA at 95 degrees caused some aggregation of 18s material with the 28s fraction.
Isolation and identification of carotenoids produced by a green alga (Dictyococcus cinnabarinus) in submerged culture
Authors: Accadia Di FD , Gribanovski-Sassu O , Romagnoli A , Tuttobello L
Published: August 2015

1. Six carotenoid pigments were produced by and isolated from the green alga Dictyococcus cinnabarinus grown in submerged culture in the presence of glucose. 2. The first, second and fourth pigments were identified respectively as beta-carotene, echinenone and canthaxanthin; the physicochemical properties of the other three are described and their similarity to other oxo-carotenoids is shown. 3. Culture techniques, isolation and identification procedures are described.
Metabolism of the reserve polysaccharide of Streptococcus mitis. Properties of a transglucosylase
Authors: Walker GJ
Published: August 2015

1. A transglucosylase has been separated from cell extracts of Streptococcus mitis, and has been partially purified by chromatography on DEAE-cellulose. 2. The transglucosylase was present in the six strains of Streptococcus mitis that were examined, and the activity of the enzyme was the same whether the cells had grown on glucose or on maltose. Four of the strains could store intracellular iodophilic polysaccharide when grown on high concentrations of glucose or maltose (1%), but none of the strains stored polysaccharide during growth on 0.1% glucose. The activity of transglucosylase in cell extracts was the same whether or not the cells had stored polysaccharide. 3. The transglucosylase degrades amylose in the presence of a suitable acceptor, transferring one or more glucosyl residues from the non-reducing end of the donor to the non-reducing end of the acceptor. With [(14)C]glucose as acceptor the maltodextrins produced were labelled in the reducing glucose unit only. 4. The enzyme can synthesize higher maltodextrins from maltose and maltotriose. Maltotetraose is disproportionated to give products of sufficient chain length to give a stain with iodine. 5. The action pattern of S. mitis during the degradation of synthetic amylose was shown to be intermediate between the single-chain and multi-chain mechanism.
Androgen sulphate formation in male and female rats
Authors: Lewis D A
Published: August 2015

1. After large doses of androsterone, epiandrosterone, dehydroepiandrosterone and testosterone, female rats excreted more of the dose conjugated with sulphuric acid than did the males. 2. Androgens were also incubated with liver slices from male and female rats. Slices from females conjugated androgens with sulphuric acid to a greater extent than did slices from males. 3. The amount of unchanged androgen present in the faeces of orally dosed animals was 4–35% of the dose.
The carbohydrate components of hydrolysates of gastric secretion and extracts from mucous glands of the gastric body mucosa and antrum
Authors: Schrager J. , Oates M. D. G.
Published: August 2015

1. The sugars and amino sugars of hydrolysates of gastric secretion were determined by gas–liquid chromatography. 2. All the gastric aspirations examined showed on hydrolysis the presence of fucose, galactose, mannose, glucose, galactosamine, glucosamine, N-acetylneuraminic acid and sulphate. 3. Galactose and glucosamine were always found in equimolar amounts, but the galactose/galactosamine ratio in different aspirations was 2:1, 3:1, 4:1 or 5:1. Repeated gastric aspirations of each subject examined showed constant ratios of these carbohydrate components. 4. Fucose and sialic acid appear to be related to glucosamine and galactosamine respectively. 5. The carbohydrate components of extracts from the mucous glands of the body mucosa and antrum did not differ from those of gastric secretion.
Structural changes in mitochondria induced by uncoupling reagents. The response to proteolytic enzymes
Authors: Weinbach Eugene C. , Garbus Joel
Published: August 2015

Interaction of uncoupling reagents with bovine serum albumin markedly inhibited its hydrolysis by proteolytic enzymes. The inhibition presumably is due to conformational transitions in the protein substrate induced by the binding of the ligand–uncoupling reagents. The proteolysis of casein, a protein that does not bind these reagents, was not affected, indicating that the proteinases themselves were not inactivated. In contrast, interaction of uncoupling reagents with freshly isolated rat liver mitochondria enhanced their susceptibility to proteolytic enzymes. This was shown by an increase in the release of ninhydrin-reacting material, by an increase in free acid groups and by a decrease in the turbidity of the mitochondrial suspensions. These effects, although opposite in direction to those obtained with albumin, are also presumed to indicate structural changes in the mitochondrial proteins and a disorganization of the protein–phospholipid complex. It is suggested that such structural alterations are expressed functionally as the uncoupling of oxidative phosphorylation.
Lactogenesis in the rat. Metabolism of uridine diphosphate galactose by mammary gland
Authors: Kuhn N. J.
Published: August 2015

1. Lactose synthetase activity in the rat mammary gland increases during the last day of pregnancy from an essentially zero value. There is a parallel increase of tissue lactose and of glucose 6-phosphate dehydrogenase activity. 2. Mammary-gland homogenates prepared both before and after parturition hydrolyse the lactose precursors glucose 6-phosphate, glucose 1-phosphate, UDP-glucose, UDP-galactose and also maltose, but not lactose. 3. A role of lactose synthetase as the rate-limiting enzyme for lactose biosynthesis and the possible significance of the hydrolytic activities are discussed with respect to lactogenesis.
Reaction of β-propiolactone with amino acids and its specificity for methionine
Authors: Taubman Martin A. , Atassi M. Z.
Published: August 2015

1. The reactions of β-propiolactone with amino acids were investigated under various conditions of pH and temperature to find those under which the reagent acted with specificity. 2. At pH9·0 and 22°, after 15min. of reaction, at least 85% of each amino acid had reacted, methionine and cystine being the most reactive. 3. At pH7·0 and 22° most amino acids reacted; methionine, cystine and histidine reacted almost entirely, and proline and lysine to a significantly smaller extent. 4. At pH3·0 and 22° further specificity was obtained; methionine and cystine were the only reactive amino acids. 5. Reaction at pH3·0 and 0° was specific for methionine; it was the only amino acid modified even after 145hr. of reaction.
A new method for determining the absolute molarity of solutions of trypsin and chymotrypsin by using p-nitrophenyl N2-acetyl-N1-benzylcarbazate
Authors: Elmore D. T. , Smyth J. J.
Published: August 2015

1. p-Nitrophenyl N2-acetyl-N1-benzylcarbazate (NPABC) was synthesized and shown to acylate α-chymotrypsin stoicheiometrically; reaction at 25° occurs almost instantaneously at pH7·04 and within 2min. at pH5·04 and there is no observable turnover during 10min. 2. The absolute molarity of solutions of α-chymotrypsin can be determined by spectrophotometric measurement of the p-nitrophenol liberated during the acylation step; the results obtained at pH5·04 and pH7·04 agree with one another and with those determined by the method of Erlanger & Edel (1964). 3. Trypsin reacts stoicheiometrically, but more slowly than α-chymotrypsin, with NPABC, and it, like chymotrypsin, can be spectrophotometrically titrated at pH7·04. At pH5·04, however, reaction between trypsin and NPABC is sufficiently slow for the reagent to be nearly specific for α-chymotrypsin. Specificity for one or other enzyme can be ensured by using soya-bean trypsin inhibitor or the chymotrypsin inhibitor l-1-chloro-3-toluene-p-sulphonamido-4-phenylbutan-2-one. Bovine thrombin does not react with NPABC. 4. Evidence is presented that indicates that acylation of α-chymotrypsin and trypsin by NPABC occurs at the active centres of the enzymes. 5. Evidence was obtained that indicates that one or more tryptophan residues move into a more hydrophobic environment when α-chymotrypsin and trypsin are acylated by NPABC.
Effect of atractyloside on glucose and pyruvate metabolism in rat diaphragm muscle
Authors: Pocchiari F. , Silano V.
Published: August 2015

1. In the presence of 1·2mm-atractyloside oxygen uptake by rat diaphragm muscle incubated with 5·6mm-glucose decreases, as well as glycogen synthesis and carbon dioxide production. Lactate formation from glucose increases, but that of phosphoglycerate diminishes fivefold. 2. When pyruvate is used as substrate, atractyloside decreases oxygen uptake. 3. The specific radioactivity of the 14CO2 (μmoles of 14CO2/μmole of oxygen), calculated at concentrations of [1−14C]pyruvate between 0·091mm and 91mm, lies between 3·1×10−4 and 5·7×10−1. Atractyloside increases the specific radioactivity of the 14CO2 with the lowest concentrations of substrate and has no effect when the substrate concentration is 91mm. 4. No appreciable effect of atractyloside on the anaerobic production of 14CO2 from [1−14C]pyruvate at various incubation times and various concentrations is found. 5. It is suggested that atractyloside induces anaerobic conditions in the tissue. Further, it produces a rise in the pyruvate concentration and an ATP deficiency in the cell. Consequently it stimulates pyruvate dismutation, and glycolysis, to which phosphorylation is linked at the substrate level.
The effect of starvation and alloxan-diabetes on the contents of citrate and other metabolic intermediates in rat liver
Authors: Start Carole , Newsholme E A
Published: August 2015

1. The content of citrate in ‘freeze-clamped’ livers from starved and alloxan-diabetic rats was measured by using the specific citrate assay method of Gruber & Moellering (1966). 2. The content of citrate fell progressively during a period of 48hr. starvation to reach a plateau value that is 50% of the value for livers from fed rats. Some possible explanations for the conflicting reports of changes in hepatic citrate content during starvation are discussed. 3. The hepatic contents of ATP, pyruvate, lactate, glycogen and the hexose phosphates were decreased during starvation, whereas those of acetyl-CoA and AMP were increased. 4. Acute alloxan-diabetes produced similar changes in the contents of these metabolic intermediates. 5. The effects of starvation and diabetes on the citrate and acetyl-CoA contents are discussed in relation to control of gluconeogenesis, fatty acid synthesis and the activity of citrate synthase.
Biosynthesis of ethylene. Enzymes involved in its formation from methional
Authors: Mapson L. W. , Wardale D. A.
Published: August 2015

1. Two enzymes were shown to be necessary for the production of ethylene from methional; they were separated from extracts of cauliflower florets by fractionation on Sephadex and other methods. 2. The first enzyme, generating hydrogen peroxide, appears to be similar to the fungal glucose oxidase, for like the latter it is highly specific for its substrate d-glucose. 3. The second enzyme, in the presence of cofactors and peroxide generated by the first enzyme, cleaves methional to ethylene. 4. It was also found that hydrogen peroxide in these reactions may be replaced by hydroperoxide generated from linolenic acid by lipoxidase enzymes. 5. Dihydroxyphenols were shown to have a marked inhibitory effect on these reactions and to account for the initial phase of low activity that is always observed in aqueous extracts prepared from the floret tissue.
The kinetics of enzyme changes in yeast under conditions that cause the loss of mitochondria
Authors: Chapman C. , Bartley W
Published: August 2015

1. Aerobically grown yeast having a high activity of glyoxylate-cycle, citric acid-cycle and electron-transport enzymes was transferred to a medium containing 10% glucose. After a lag phase of 30min. the yeast grew exponentially with a mean generation time of 94min. 2. The enzymes malate dehydrogenase, isocitrate lyase, succinate–cytochrome c oxidoreductase and NADH–cytochrome c oxidoreductase lost 45%, 17%, 27% and 46% of their activity respectively during the lag phase. 3. When growth commenced pyruvate kinase, pyruvate decarboxylase, alcohol dehydrogenase, glutamate dehydrogenase (NADP+-linked) and NADPH–cytochrome c oxidoreductase increased in activity, whereas aconitase, isocitrate dehydrogenase (NAD+- and NADP+-linked), α-oxoglutarate dehydrogenase, fumarase, malate dehydrogenase, succinate–cytochrome c oxidoreductase, NADH–cytochrome c oxidoreductase, NADH oxidase, NADPH oxidase, cytochrome c oxidase, glutamate dehydrogenase (NAD+-linked), glutamate–oxaloacetate transaminase, isocitrate lyase and glucose 6-phosphate dehydrogenase decreased. 4. During the early stages of growth the loss of activity of aconitase, α-oxoglutarate dehydrogenase, fumarase and glucose 6-phosphate dehydrogenase could be accounted for by dilution by cell division. The lower rate of loss of activity of isocitrate dehydrogenase (NAD+- and NADP+-linked), glutamate dehydrogenase (NAD+-linked), glutamate–oxaloacetate transaminase, NADPH oxidase and cytochrome c oxidase implies their continued synthesis, whereas the higher rate of loss of activity of malate dehydrogenase, isocitrate lyase, succinate–cytochrome c oxidoreductase, NADH–cytochrome c oxidoreductase and NADH oxidase means that these enzymes were actively removed. 5. The mechanisms of selective removal of enzyme activity and the control of the residual metabolic pathways are discussed.
Human kidney and urinary alkaline phosphatases
Authors: Butterworth P. J.
Published: August 2015

1. Four fractions of kidney alkaline phosphatase were prepared by chromatography on DEAE-Sephadex. An investigation of their properties suggests that the fractions represent modifications of a single kidney enzyme. 2. Urinary alkaline phosphatase resembles kidney enzyme in most of its properties, but differs in Km and in the degree by which it is activated by Mg2+ ions. 3. Estimates of the molecular weights of kidney and urinary alkaline phosphatase gave values of 150000–170000 for kidney phosphatase and 75000 for the urinary enzyme. 4. It is suggested that urinary alkaline phosphatase is a sub-unit of kidney phosphatase, but it has not been possible to simulate the formation of urinary enzyme by treating kidney enzyme with urea or H+ ions.
The significance of cytochrome c redistribution during the subcellular fractionation of rat liver
Authors: González-Cadavid N. F. , Bravo María , Campbell P. N.
Published: August 2015

1. The redistribution of mitochondrial cytochrome c during homogenization and subcellular fractionation of the liver was studied. Chromatographically homogeneous 14C-labelled cytochrome c was added in different amounts to liver suspensions immediately before homogenization and the adsorption of radioactivity was determined in cytochrome c fractions extracted at pH4·0, first with water and then with 0·15m-sodium chloride. 2. The soluble cytochrome c remaining in the cell sap after subcellular fractionation was 7% of the calculated amount of cytochrome c passing through a soluble form during the whole process. The total amount of cytochrome c released in a soluble form and subsequently redistributed was 25–30% of the total liver cytochrome c. 3. In the standard microsomal fraction the cytochrome c extracted with water originated entirely from redistribution whereas that extracted with 0·15m-sodium chloride was 80% endogenous. In the mitochondrial fraction both cytochrome c pools were truly endogenous, so that practically none of the mitochondrial cytochrome c released to the soluble cell sap was readsorbed by the mitochondria. 4. These results support our former hypothesis that the cytochrome c extracted with 0·15m-sodium chloride at pH4·0 from the standard microsomes represents the cytochrome c newly synthesized in situ, since it does not originate from redistribution. However, the microsomal pool extracted with water cannot be an intermediate in the postulated transfer of cytochrome c from the microsomal particles to the mitochondria, since this pool arises from redistribution of mitochondrial cytochrome c.
Polyamines and nucleic acid metabolism in chick embryo. Incorporation of labelled precursors into nucleic acids of subcellular fractions and polyribosomal patterns
Authors: Moruzzi G. , Barbiroli B , Caldarera C. M.
Published: August 2015

1. An increase in polyamine concentration, caused by inhibiting the amine oxidase activities with iproniazid, increased the incorporation of [3H]orotic acid into chick-embryo RNA and DNA. On the other hand, a decrease in polyamine concentration, obtained by causing an increase in amine oxidase activities, decreased [3H]orotic acid incorporation into nucleic acids. This was particularly evident for nuclear DNA and ribosomal RNA. 2. Polyribosomal patterns obtained by sucrose-density-gradient centrifugation showed highest radioactivity in the regions of 259s and 280s aggregates in those embryos in which the polyamine contents were enhanced, whereas a decrease in the radioactivity was observed when the polyamine concentrations were decreased. 3. The activity of DNA-dependent RNA polymerase, assayed in the same experimental conditions, also varied in the same fashion with changes in polyamine concentration.
Some properties of β-fructofuranosidases partially purified from Phaseolus vulgaris and Solanum tuberosum
Authors: Frost G. M. , Greenshields R. N. , Teale F. W. J.
Published: August 2015

1. Soluble β-fructofuranosidases were purified 16-fold from French-bean-pod extracts and 35-fold from potato-tuber extracts. 2. The two enzymes had similar overall properties but differed from each other quantitatively in lability and reaction kinetics. 3. A non-diffusible inhibitor of β-fructofuranosidase was present in the potato-tuber extracts but was absent from the bean extracts. This non-competitive inhibitor was acid-labile. 4. The possible roles of imidazole, carboxyl and thiol groups in β-fructofuranosidase action are discussed, and the properties of the bean and potato enzymes are compared with published data for yeast, mould and grape-berry enzymes.
The metabolism of d-galactosamine and N-acetyl-d-galactosamine in rat liver
Authors: Maley Frank , Tarentino Anthony L. , McGarrahan John F. , DelGiacco Rudolph
Published: August 2015

d-[1−14C]Galactosamine appears to be utilized mainly by the pathway of galactose metabolism in rat liver, as evidenced by the products isolated from the acid-soluble fraction of perfused rat liver. These products were eluted in the following order from a Dowex 1 (formate form) column and were characterized as galactosamine 1-phosphate, sialic acid, UDP-glucosamine, UDP-galactosamine, N-acetylgalactosamine 1-phosphate, N-acetylglucosamine 6-phosphate, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine and an unidentified galactosamine-containing compound. In addition, [1−14C]glucosamine was found in the glycogen, an incorporation previously shown to result from the substitution of UDP-glucosamine for UDP-glucose in the glycogen synthetase reaction. Analysis of the [1−14C]glucosamine-containing disaccharides released from glycogen by β-amylase provided additional evidence that they consist of a mixture of glucose and glucosamine in a 1:1 ratio, but with glucose predominating on the reducing end. UDP-N-acetylgalactosamine was shown to result from the reaction of UTP with N-acetylgalactosamine 1-phosphate in the presence of a rat liver extract.
Choice between autotrophy and heterotrophy in Pseudomonas oxalaticus. Growth in mixed substrates
Authors: Blackmore Maureen A. , Quayle J. R.
Published: August 2015

1. The type of metabolism adopted by Pseudomonas oxalaticus during growth on a variety of carbon sources was studied. 2. The only substrate upon which autotrophic growth was observed is formate. 3. In mixtures of formate and those substrates upon which the organism can grow faster than on formate, e.g. succinate, lactate or citrate, heterotrophic metabolism results. 4. In mixtures of formate and those substrates upon which the organism can grow at a similar rate to that on formate, e.g. glycollate or glyoxylate, the predominant mode of metabolism adopted is heterotrophic utilization of the C2 substrate coupled with oxidation of formate as ancillary energy source. 5. P. oxalaticus grows on oxalate 30% slower than on formate. In mixtures of formate and oxalate, the predominant mode of metabolism adopted is autotrophic utilization of formate coupled with oxidation of oxalate as ancillary energy source. 6. In mixtures of formate and those substrates upon which the organism grows at a much lower rate than on formate, e.g. glycerol and malonate, the predominant mode of metabolism adopted is autotrophic utilization of formate. 7. It is concluded that synthesis of the enzymes involved in autotrophic metabolism is controlled by a combination of induction and metabolite repression.
Protein–carbohydrate interaction. A turbidimetric study of the interaction of concanavalin A with amylopectin and glycogen and some of their enzymic and chemical degradation products
Authors: Smith E. E. , Smith Zeenat H. Gunja , Goldstein I. J.
Published: August 2015

The interaction of the plant protein concanavalin A with glycogen and amylopectin was studied. The protein concentration-dependency of the interaction and the effect on the interaction of various enzymic and chemical degradations of the polysaccharides were investigated by using a turbidimetric technique. The results indicate that, in addition to certain structural requirements, the molecular weight of the polysaccharides and the concentration of protein are important factors controlling the extent of interaction. The observed similarity of the interaction of polysaccharides with concanavalin A to the more specific polysaccharide–protein interactions indicates that it should provide a useful model system for the study of these interactions in general.
Studies on the sub-units of triose phosphate isomerase
Authors: Burton Pamela M. , Waley S. G.
Published: August 2015

The sub-unit structure of rabbit muscle triose phosphate isomerase was studied by determination of the number of unique cysteine peptides. Alkylation of the thiol groups with radioactive iodoacetate in the presence of guanidine hydrochloride gave the S-carboxy[14C]methyl derivative of the protein. This was digested with trypsin, and the radioactive peptides were fractionated by ion-exchange chromatography; four main radioactive peaks were obtained, one of which contained two radioactive peptides. Peptide ‘maps’ of the tryptic digest showed five main spots. The relationship between the members of both sets of five peptides was established. The radioactive peptides were characterized, and the results indicated the presence of five unique cysteine residues in the protein. Since there are approximately ten thiol groups/molecule, there are two closely related or identical sub-units. Studies of the terminal residues bear out this suggestion; only one kind of N-terminal residue (alanine) and one kind of C-terminal residue (glutamine) were detected. These results are in accord with the evidence from crystallography.
Studies on the existence of a pathway in liver and muscle for the conversion of glucose into glycogen without glucose 6-phosphate as an intermediate
Authors: Antony Gabor J. , Srinivasan Indira , Williams Hollis R. , Landau Bernard R.
Published: August 2015

Mixtures of 14C-labelled glucose plus pyruvate were incubated either with rat diaphragm or slices of rat liver. Incorporation of glucose carbon into glycogen was compared with its incorporation into glucose 6-phosphate relative to the incorporation of pyruvate carbon into these metabolic products. There was no preferential incorporation of glucose carbon relative to pyruvate carbon into glycogen compared with glucose 6-phosphate in the liver slices, but there was in diaphragm. On the assumption that glucose 6-phosphate is a necessary intermediate in the conversion of pyruvate carbon into glycogen, this is evidence for the existence in muscle, but not in liver, of more than one pool of glucose 6-phosphate or of a pathway from glucose to glycogen without glucose 6-phosphate as an intermediate. Galactose carbon, relative to pyruvate carbon, was preferentially incorporated into liver glycogen, so that a substrate converted in liver into glycogen without glucose 6-phosphate as an intermediate could be detected by this approach.
Studies on S-adenosylmethionine–magnesium protoporphyrin methyltransferase in Euglena gracilis strain Z
Authors: Ebbon Jean G. , Tait G. H.
Published: August 2015

1. An enzyme that methylates magnesium protoporphyrin was detected in extracts of light-grown and dark-grown cells of Euglena gracilis. The activity in light-grown cells is two to three times that in cells grown in the dark. 2. The activity is mainly located in the chloroplast fraction from light-grown cells and in proplastids in dark-grown cells. However, in cells grown either in the light or dark, about 15–20% is found in particle-free supernatant. 3. The chloroplast methylating enzyme was solubilized by the action of Tween 80 and partially purified. The properties were investigated. 4. From experiments in which etiolated cells were illuminated in the presence of inhibitors of chloroplast or cytoplasmic protein synthesis, it appears that the methylating enzyme is made on cytoplasmic ribosomes.
A nucleoside triphosphate-dependent deoxyribonucleic acid-breakdown system in Mycobacterium smegmatis, and the effect of iron limitation on the activity of this system
Authors: Winder F. G. , Coughlan M. P.
Published: August 2015

1. The presence of a nucleoside triphosphate-dependent DNA-breakdown system was demonstrated in extracts of Mycobacterium smegmatis. Its activity was increased substantially by iron limitation, apparently after the fall in DNA content that took place under these conditions. A maximal activity of about 0·2μmole of deoxyribonucleotide/30min./mg. of protein was found in crude extracts. 2. After slight purification by streptomycin treatment, the enzyme showed maximal activity with undenatured DNA (Km≃200μg./ml.), ATP (Km≃1·2mm) or UTP, CTP and GTP giving lower activity and pyrophosphate giving none, and Mg2+ ions (optimum concn. 12mm). The optimum pH was 8·5. 3. In the assay system there was proportionality between enzyme concentration and rate of reaction, but the rate fell off with time. 4. ATP was broken down in the reaction and monodeoxy-ribonucleotides were among the products, but the presence of some oligodeoxy-ribonucleotides was not excluded and the degree of phosphorylation of the primary products was uncertain.
A peptide containing a reactive lysyl group from ox liver glutamate dehydrogenase
Authors: Holbrook J. J. , Jeckel Renate
Published: August 2015

1. Inhibition of ox liver glutamate dehydrogenase with N-(N′-acetyl-4[35S]-sulphamoylphenyl)maleimide (ASPM) is more specific at pH7·3 than at pH6·9. At pH7·3 inhibition accompanies the incorporation at 1 mole of ASPM residues into about 53000g. of protein. 2. Digestion of the modified protein with chymotrypsin and trypsin yields a unique radioactive peptide. 3. Acid hydrolysis of 1 mole of this peptide yields 1 mole of N∈-succin-2-yl-lysine. The ∈-amino group of a lysyl residue is thus the site of modification of the protein. 4. The sequence containing the modified lysyl residue is: [Formula: see text] where Asx respresents either aspartic acid or asparagine.