bluuebunny/crossref_metadata_2025 huggingface dataset:
A high-spin organic diradical as a spin filter
Authors: Shil Suranjan , Bhattacharya Debojit , Misra Anirban , Klein Douglas J.
Published: August 2015

A highly ferromagnetic m-phenylene connected bis(aminoxyl) diradical used as a spin filter.
Retinal shows its true colours: photoisomerization action spectra of mobility-selected isomers of the retinal protonated Schiff base
Authors: Coughlan N. J. A. , Adamson B. D. , Gamon L. , Catani K. , Bieske E. J.
Published: August 2015

Isomers of the retinal protonated Schiff base are separated and probed using laser radiation in a tandem ion mobility spectrometer yielding isomer-specific electronic spectra.
Dehydrocoupling routes to element–element bonds catalysed by main group compounds
Authors: Melen Rebecca L.
Published: August 2015

This Tutorial Review focuses on recent applications of main group compounds in the catalytic synthesis of heteronuclear element–element bonds within the p-block.
Eco-friendly and facilely prepared silica modified amorphous titania (TiO2–SiO2) electrocatalyst for the O2 and H2 evolution reactions
Authors: Venkatkarthick R. , Davidson D. J. , Ravichandran S. , Vengatesan S. , Sozhan G. , Vasudevan S.
Published: August 2015

A silica modified amorphous titania (TiO2–SiO2) electrocatalyst was prepared by a simple, cheap, and scalable preparation procedure. The catalyst is active in the oxygen and hydrogen evolution reactions, leading to a promising bifunctional electrocatalyst.
Controlling dimensionality via a dual ligand strategy in Ln-thiophene-2,5-dicarboxylic acid-terpyridine coordination polymers
Authors: Carter Korey P. , Zulato Cecília H. F. , Rodrigues Emille M. , Pope Simon J. A. , Sigoli Fernando A. , Cahill Christopher L.
Published: August 2015

Eleven new lanthanide-2,5-TDC-terpyridine coordination polymers which employ a dual ligand strategy have been synthesized and characterized by single crystal and powder X-ray diffraction as well as luminescence spectroscopy.
Anion exchange capacity of biochar
Authors: Lawrinenko Michael , Laird David A.
Published: August 2015

Biochar has gained recent interest as a soil amendment and agent for carbon sequestration.
Prioritization of rheumatoid arthritis risk subpathways based on global immune subpathway interaction network and random walk strategy
Authors: Lv Wenhua , Wang Qiuyu , Chen He , Jiang Yongshuai , Zheng Jiajia , Shi Miao , Xu Yanjun , Han Junwei , Li Chunquan , Zhang Ruijie
Published: August 2015

The initiation and development of rheumatoid arthritis (RA) is closely related to mutual dysfunction of multiple pathways.
Controlled intracellular generation of reactive oxygen species in human mesenchymal stem cells using porphyrin conjugated nanoparticles
Authors: Lavado Andrea S. , Chauhan Veeren M. , Alhaj Zen Amer , Giuntini Francesca , Jones D. Rhodri E. , Boyle Ross W. , Beeby Andrew , Chan Weng C. , Aylott Jonathan W.
Published: August 2015

Newly synthesised Zn (ii) porphyrin nanoparticle conjugates were irradiated with visible light to generate controlled amounts of ROS in hMSCs to advance the study of oxidative stress and cellular communication.
Discovering functional, non-proteinogenic amino acid containing, peptides using genetic code reprogramming
Authors: Rogers J. M. , Suga H.
Published: August 2015

We review the methods of genetic code reprogramming and their use in discovering novel linear and cyclic polypeptides with non-proteinogenic chemistry.
Construction of benzo-fused indolizines, pyrrolo[1,2-a]quinolines via alkyne–carbonyl metathesis
Authors: Nayak Maloy , Kim Ikyon
Published: August 2015

The strategic use of a sequential Sonogashira coupling/intramolecular alkyne–carbonyl metathesis process for the synthesis of a pyridine ring from 1-(2-haloaryl)-1H-pyrrole-2-carbaldehydes allowed ready access to diverse novel benzo-fused indolizines, pyrrolo[1,2-a]quinolines, in good to excellent yields.
Oligonucleotides containing a ribo-configured cyclohexanyl nucleoside: probing the role of sugar conformation in base pairing selectivity
Authors: Paolella Concetta , D'Alonzo Daniele , Schepers Guy , Van Aerschot Arthur , Di Fabio Giovanni , Palumbo Giovanni , Herdewijn Piet , Guaragna Annalisa
Published: August 2015

A relationship between pairing selectivity and “sugar” conformation of six-membered nucleic acids is suggested by the study of the novel oligonucleotide system r-CNA.
Microstructure and properties of novel SPEEK/PVDF-g-PSSA blends for proton exchange membrane with improved compatibility
Authors: Liu Xu , Meng Xiaoyu , Wu Juntao , Huo Jiangbei , Cui Lishan , Zhou Qiong
Published: August 2015

Design and fabrication of a novel series of high performance SPEEK/PVDF-g-PSSA blend membranes with improved compatibility via grafting method.
Chemical control of continuous light-steering using an array of gradient Au/Bi2Se3/Au strips
Authors: Cao Tun , Zheng Guangzhao , Wang Shuai
Published: August 2015

Achievement of continuous light-steering in an array of gradient Au/Bi2Se3/Au strips by modulating the dielectric function of Bi2Se3.
Honey enhances the anti-quorum sensing activity and anti-biofilm potential of curcumin
Authors: Jadaun V. , Prateeksha Prateeksha , Singh Braj R. , Paliya B. S. , Upreti D. K. , Rao Ch. V. , Rawat A. K. S. , Singh Brahma N.
Published: August 2015

In this investigation, the potential of curcumin (50 μg mL−1) plus 1% of honey (ChC) in reducing QS-mediated production of virulence factors and biofilm formation inPseudomonas aeruginosaPAO1 was studied.
Diffusive dynamics of nanoparticles in ultra-confined media
Authors: Jacob Jack Deodato C. , He Kai , Retterer Scott T. , Krishnamoorti Ramanan , Conrad Jacinta C.
Published: August 2015

Hydrodynamic models incorporating volume exclusion and hydrodynamic drag describe the slowing of diffusion of nanoparticles strongly confined in nanopost arrays.
Magnetic field assisted programming of particle shapes and patterns
Authors: Xu Wenwen , Yao Yuyu , Klassen John S. , Serpe Michael J.
Published: August 2015

Particles with an array of shapes and complex internal structure can be generated in a simple and straightforward manner.
Porous NaTi2(PO4)3nanocubes: a high-rate nonaqueous sodium anode material with more than 10 000 cycle life
Authors: Yang Gongzheng , Song Huawei , Wu Mingmei , Wang Chengxin
Published: August 2015

Four porous NaTi2(PO4)3nanocubes were synthesizedviaa one-pot solvothermal method for high-rate sodium ion battery anodes.
Ultra-lightweight PANiNF/MWCNT-functionalized separators with synergistic suppression of polysulfide migration for Li–S batteries with pure sulfur cathodes
Authors: Chang Chi-Hao , Chung Sheng-Heng , Manthiram Arumugam
Published: August 2015

A custom separator with an ultra-lightweight polyaniline nanofiber/multiwall carbon nanotube (PANiNF/MWCNT) coating has been utilized to improve the electrochemical performance of lithium–sulfur (Li–S) batteries.
Synthesis of pH-responsive hydrogel thin films grafted on PCL substrates for protein delivery
Authors: Zhang Lihua , Ma Yuhong , Zhao Changwen , Zhu Xing , Chen Ruichao , Yang Wantai
Published: August 2015

A new visible light induced graft polymerization method was utilized to prepare pH-sensitive hydrogel layers covalently attached to polymer substrates for drug delivery.
Killing cancer cells using nanotechnology: novel poly(I:C) loaded liposome–silica hybrid nanoparticles
Authors: Colapicchioni Valentina , Palchetti Sara , Pozzi Daniela , Marini Elettra Sara , Riccioli Anna , Ziparo Elio , Papi Massimiliano , Amenitsch Heinz , Caracciolo Giulio
Published: August 2015

Synthesized core–shell liposome–silica hybrid nanoparticles (LSH NPs), when loaded with the anti-cancer polyinosinic–polycytidylic acid (poly(I:C)), exhibit high anti-tumoral activity in prostate and breast cancer cells.
Strategies for engineering phonon transport in thermoelectrics
Authors: Kim Woochul
Published: August 2015

We discuss representative strategies of phonon engineering by categorizing them into the methods affecting each component of thermal conductivity.
Associations of amino acids and related compounds in the seeds of forty-seven species of Vicia: their taxonomic and nutritional significance
Authors: Bell EA , Tirimanna ASL
Published: August 2015

1. The genus Vicia may be subdivided into groups of species characterized by associations of ninhydrin-positive compounds occurring in high concentrations in their seeds. Despite these subdivisions the overall distribution pattern emphasizes the unity of the genus and the possible value of such studies in establishing degrees of relationship between species within the genus. 2. Canavanine is a major constituent in the seeds of 17 species. 3. gamma-Hydroxyarginine, an amino acid that has not been found in other plant genera, occurs in 18 species. 4. gamma-Hydroxyornithine, a new natural amino acid, is found in two species. 5. A new naturally occurring ureido amino acid tentatively identified as; gamma-hydroxycitrulline' is found in two species. 6. High concentrations of alphabeta-diaminopropionic acid are found in seed of V. baicalensis and of alphagamma-diaminobutyric acid in seed of V. aurantica. 7. The neurotoxic amino acid beta-cyanoalanine and its gamma-glutamyl peptide are found together in high concentrations in the seeds of 16 species of this agriculturally important genus. 8. Seven unidentified ninhydrin-positive compounds occur in high concentration (about 1% of the dry weight or more) in the seed of various species. Details of their R(F) values, ionic mobilities and colour reactions are given. 9. The total concentration of extractable ninhydrin-positive compounds varies little between seeds of different species and these compounds may, as has been suggested for those in Lathyrus, constitute a readily available form of storage nitrogen. 10. The nature and distribution, as opposed to the total concentration, of the amino acids and related compounds accumulated in the seeds of Vicia are different from those accumulated in the seeds of the related genus, Lathyrus. One particularly interesting difference is the accumulation of C(6) guanidino amino acids (arginine and gamma-hydroxyarginine) by Vicia and the accumulation of C(7) guanidino amino acids (homoarginine, gamma-hydroxyhomoarginine and the related amino acid lathyrine) by Lathyrus. Such differences afford a method for distinguishing between species of these genera.
Effect of diethylstilboestrol on adipose-tissue lipids
Authors: Sink JD , Huston CK , Shigley JW
Published: August 2015

1. The effect of diethylstilboestrol on the fatty acid composition of adipose-tissue lipids of the ox (Bos taurus) was studied. 2. The capsula adiposa (perirenal) was shown to contain more total saturated fatty acids, whereas more total unsaturated fatty acids were found in the panniculus adiposus (subcutaneous). 3. Significantly more stearic acid and linolenic acid were obtained from the capsula adiposa, whereas the panniculus adiposus contained more myristoleic acid, palmitoleic acid and oleic acid. 4. Implanting diethylstilboestrol significantly increased the deposition of the saturated fatty acids, particularly stearic acid. 5. A decrease in the deposition of total unsaturated fatty acids, myristoleic acid, palmitoleic acid and linoleic acid can also be attributed to the diethylstilboestrol treatment.
The enzymic reduction of nicotinamide-adenine dinucleotide by 2-mercaptoethanol
Authors: Lambe RF , Williams DC
Published: August 2015

1. The reduction of NAD(+), by an enzyme preparation from rat liver, in the presence of 2-mercaptoethanol is reported. 2. It is suggested that the NAD(+)-linked alcohol dehydrogenase in the extract transfers hydrogen from 2-mercaptoethanol to NAD(+). 3. Both yeast and horse-liver alcohol dehydrogenases were observed to reduce NAD(+) in the presence of 2-mercaptoethanol. 4. Some interactions of 2-mercaptoethanol, cysteine or hydroxylamine with the alcohol dehydrogenases from rat liver, horse liver and yeast are discussed.
Influence of sex and gonadal hormones on rat-liver and carcass lipids during the development of an essential fatty acid deficiency
Authors: Ostwald R , Bouchard P , Miljanich P , Lyman RL
Published: August 2015

1. Groups of intact male and female rats and castrated rats injected with oestradiol or testosterone were given a diet containing hydrogenated coconut oil for 9 weeks, and at intervals the amounts and fatty acid compositions of the carcass and liver lipids were determined. 2. Male rats grew faster and larger, and exhibited typical external essential fatty acid deficiency symptoms sooner than did females. Testosterone-treated castrated male rats were similar to males, and oestradiol-injected castrated male rats resembled females. 3. Intact females maintained a higher linoleic acid concentration in their carcass than did males. Total amounts of carcass linoleic acid remained similar for all groups, only 200mg. being removed in 9 weeks regardless of body size. 4. The amounts of total cholesteryl esters were independent of liver size. They were higher in males and testosterone-treated castrated male rats than in females and oestrogen-treated castrated male rats. 5. Phospholipids represented about 80% of the liver lipids. The total amounts of the phospholipid linoleic acid and arachidonic acid were similar for all groups regardless of liver size, and were not affected appreciably by the deficiency. Females and oestrogen-treated castrated male rats maintained a higher proportion of phospholipid arachidonic acid for longer periods than did their male counterparts. Both the total amounts and the proportions of eicosatrienoic acid and palmitic acid were higher in males than in females. 6. Supplementation of the essential fatty acid-deficient diet with linoleic acid caused a rapid loss of eicosatrienoic acid and palmitic acid with a concomitant increase in stearic acid and arachidonic acid. 7. There were no obvious differences in the way that the essential fatty acids were metabolized or mobilized from adipose tissue of male or female rats during essential fatty acid deficiency. 8. The results indicated that the greater growth rate of the male rats caused them to require and synthesize more phospholipids than did the females. In the absence of adequate amounts of arachidonic acid, eicosatrienoic acid was substituted into the additional phospholipid. The earlier symptoms of essential fatty acid deficiency in the male rat could therefore be ascribed to the higher tissue concentrations of this unnatural phospholipid and its inability to perform the normal metabolic functions of phospholipids.
Effect of oestradiol 3-benzoate on the concentrations of retinal and lipids in cod plasma
Authors: Plack P. A. , Pritchard D. J.
Published: August 2015

1. Determinations of retinal, total lipid and lipid phosphorus were made on 10ml. samples of cod plasma. 2. Immature control fish, injected with 0·2ml. of carrier oil/kg. wt., had 0·73±0·12μg. of retinal/100ml. of plasma, and maturing male fish had similar concentrations. Maturing female fish had about 10μg. of retinal/100ml. of plasma. 3. Immature male or female cod given single intramuscular injections of 1mg. of oestradiol-17β 3-benzoate in 0·2ml. of oil/kg. wt. had 8·54±0·59 μg. of retinal/100ml. of plasma after 5 days and about 25μg./100ml. of plasma after 10 days. 4. Oestradiol injections had little effect on the concentration of plasma phospholipids, and no effect on lipids other than phospholipids. 5. For all 116 fish examined, regardless of sex or treatment, the concentration of plasma phospholipid was significantly correlated with that of lipids other than phospholipids (r=0·727), and phospholipids formed 50·4% of the total lipids in cod plasma. 6. Alcohol dehydrogenase was purified from cod liver and shown to oxidize retinol to retinal. It was completely inhibited by 0·1mm-oestradiol. Alternative modes of action of oestradiol are discussed.
Behaviour of the NO-β-d-glucosiduronic acid of N-acetyl-N-phenylhydroxylamine as a substrate for β-glucuronidase
Authors: Ide Hiroyuki , Green Sidney , Kato Keitaro , Fishman William H.
Published: August 2015

1. Biosynthetic sodium (N-acetyl-N-phenylhydroxylamine NO-β-d-glucosid)-uronate is hydrolysed completely by purified mouse urinary β-glucuronidase into the products N-acetyl-N-phenylhydroxylamine and glucuronic acid. The hydrolysis is inhibited by saccharo-(1→4)-lactone. These results not only confirm the identity and purity of the substrate but also establish it as a substrate for β-glucuronidase. 2. Mammalian and bacterial β-glucuronidase preparations hydrolysed the substrate at a rate one-fifth of that for (phenolphthalein β-d-glucosid)uronic acid under the optimum conditions of hydrolysis for each source. 3. The pH optimum is 4·1 and the Michaelis constant, Km, is 3·3×10−4m with purified mouse urinary β-glucuronidase as the enzyme source acting on the NO-β-d-glucosiduronic acid. The aglycone after extraction into chloroform was quantitatively determined spectrophotometrically at its absorption maximum (256mμ). 4. The hydrolysis was studied as a function of time and temperature. 5. From a consideration of the chemical and enzymic properties of this NO-β-d-glucosiduronic acid it is possible to suggest its catabolism in vivo.
Degradation of phenylalanine and tyrosine by Sporobolomyces roseus
Authors: Moore Keith , Rao P. V. Subba , Towers G. H. N.
Published: August 2015

Ammonia-lyase activity for l-phenylalanine, m-hydroxyphenylalanine and l-tyrosine was demonstrated in cell-free extracts of Sporobolomyces roseus. Cultures of this organism converted dl-[ring−14C]phenylalanine and l-[U−14C]tyrosine into the corresponding cinnamic acid. Tracer studies showed that these compounds were further metabolized to [14C]protocatechuic acid. Benzoic acid and p-hydroxybenzoic acid were intermediates in this pathway. Washed cells of the organism readily utilized cinnamic acid, p-coumaric acid, caffeic acid, benzoic acid and p-hydroxybenzoic acid. Protocatechuic acid was the terminal aromatic compound formed during the metabolism of these compounds. The cells of S. roseus were able to convert m-coumaric acid into m-hydroxybenzoic acid, but the latter compound, which accumulated in the medium, was not further metabolized. 4-Hydroxycoumarin was identified as the product of o-coumaric acid metabolism by this organism.
Isolation and a partial amino acid sequence of insulin from the islet tissue of cod (Gadus callarias)
Authors: Grant P T , Reid K. B. M.
Published: August 2015

1. Insulin has been isolated by gel filtration and ion-exchange chromatography from extracts of the discrete islet tissue of cod. The final preparation yielded a single band on electrophoresis at two pH values. The biological potency was 11·5 international units/mg. in mouse-convulsion and other assay procedures. 2. Glycine and methionine were shown to be the N-terminal amino acids of the A and B chains respectively. An estimate of the molecular weight together with amino acid analyses indicated that cod insulin, like the bovine hormone, consists of 51 amino acid residues. In contrast, the amino acid composition differs markedly from bovine insulin. 3. Oxidation of insulin with performic acid yielded the A and B peptide chains, which were separated by ion-exchange chromatography. Sequence studies on smaller peptides isolated from enzymic digests or from dilute acetic acid hydrolysates of the two chains have established the sequential order of 14 of the 21 amino acid residues of the A chain and 25 of the 30 amino acid residues of the B chain.
Studies on extracellular ribonucleases of Ustilago sphaerogena. Characterization of substrate specificity with special reference to purine-specific ribonucleases
Authors: Arima Terukatsu , Uchida Tsuneko , Egami Fujio
Published: August 2015

1. Ribonuclease U1 splits only the phosphodiester bonds of guanosine 3′-phosphates in RNA. It may be regarded as a guanyloribonuclease [ribonucleate (guanine nucleotide)-2′-transferase (cyclizing), EC 2.7.7.26] similar to ribonuclease T1 (Egami, Takahashi & Uchida, 1964). It seems to be identical with the extracellular ribonuclease described by Glitz & Dekker (1963, 1964a,b). 2. Ribonucleases U2 and U3 are novel enzymes with a strict specificity. They split the internucleotide bonds between purine 3′-nucleotides and 5′-hydroxy groups of adjacent nucleotides in RNA with the intermediary formation of purine nucleoside 2′,3′-(cyclic)-phosphates, which are slowly hydrolysed to purine 3′-nucleotides. So they may be classified as ‘puryloribonucleases [ribonucleate (purine nucleotide)-2′-transferase (cyclizing)]’. Double-stranded RNA is scarcely split by ribonucleases U2 and U3. 3. Ribonuclease U4 has no absolute base specificity, and produces the mononucleotides 3′-adenylate, 3′-guanylate, 3′-cytidylate and 3′-uridylate from RNA.
The introduction of the C-22–C-23 ethylenic linkage in ergosterol biosynthesis
Authors: Akhtar M , Parvez M. A. , Hunt P. F.
Published: August 2015

Methods for the chemical synthesis of [23−3H2]lanosterol, [23,25−3H3]24-methyldihydrolanosterol and [24,28−3H2]24-methyldihydrolanosterol are described. It is shown that, in the biosynthesis of ergosterol from [26,27−14C2,23−3H2]lanosterol by the whole cells of Saccharomyces cerevisiae, one of the original C-23 hydrogen atoms is lost and the other is retained at C-23 of ergosterol. It is also shown that 24-methyldihydrolanosterol is converted into ergosterol in good yield and without prior conversion into a 24-methylene derivative. On the basis of these results possible pathways for the formation of the ergosterol side chain from a 24-methylene side chain are discussed.
Chloroplast and cytoplasmic low-molecular-weight ribonucleic acid components of the leaf of Vicia faba L.
Authors: Dyer T. A. , Leech Rachel M.
Published: August 2015

1. A method for the extraction of plant nucleic acids and their separation on methylated-serum-albumin–kieselguhr columns is described. It is demonstrated that the characteristics of the elution profiles of material from the same source are consistently reproducible. 2. Major dissimilarities were found in the elution profiles of nucleic acids from root and from leaves of Vicia faba L. These dissimilarities were confirmed by polyacrylamide-gel electrophoresis. 3. Four distinct types of low-molecular-weight RNA were demonstrated to be present in leaves, clearly distinguished by their behaviour when chromatographed on methylated-serum-albumin–kieselguhr columns. (a) Both cytoplasmic and chloroplast ribosomes contained a low-molecular-weight RNA, and these components were distinct from each other. (b) The chloroplast possessed a unique ‘soluble’ RNA (i.e. RNA that is not precipitated by centrifugal forces that sediment ribosomes) which was not present in the rest of the cell. (c) A soluble component, probably transfer RNA, was found in both the chloroplasts and in the cytoplasm. 4. The components distinguishable by methylated-serum-albumin–kieselguhr column chromatography could not be distinguished by sucrose-density-gradient centrifugation.
The purification and amino acid composition of human uterus collagens, rheumatoid-arthritis-nodule collagen and ox tendon collagen
Authors: Harding J J , Wesley J. M.
Published: August 2015

Collagens and gelatins were isolated from human post-menopausal uterus, puerperal (post-partum) uterus, rheumatoid-arthritis-nodule and ox tendon. Different means of purifying collagen were studied and a method was devised that enables highly purified collagen to be obtained, even from the uterus. This method involves the use of a number of aqueous and organic extractants as well as digestion with elastase to eliminate elastin. The purity of the collagen preparations was assessed and they were used to study the amino acid composition of collagen. The amino acid compositions of all the collagens studied were similar to those of human bone and tendon collagen, but certain small differences were noted and are discussed. The soluble collagen extracted from some of the tissues was also studied.
Purification of rabbit kidney cytokinase and a comparison of its properties with human urokinase
Authors: Ali S. Y. , Evans Lois
Published: August 2015

1. The cytokinase (tissue activator of plasminogen) content of several mammalian tissues was evaluated by a quantitative casein hydrolysis method. 2. An alkaline (pH10·5) extraction of cytokinase from rabbit kidney lysosome–microsome fraction, followed by chromatography on DEAE-cellulose at pH7·6 with stepwise or linear increase in concentration of phosphate buffer, gave an 86-fold purification of the enzyme. The purified material was non-proteolytic against casein and heated fibrin and was freeze-dried without significant loss of activity or solubility. 3. Cytokinase is a protein with E0·1%1cm.=0·87 at 280mμ, and does not possess sufficient hexose or sialic acid to be classified as a glycoprotein. It has S20,w 2·9–3·1s and molecular weight 50000 when measured on a calibrated Sephadex G-100 column. It has an isoelectric point between pH8 and pH9, and is maximally active and stable at pH8·5. It is inactivated by heat at 78°. 4. Cytokinase and human urokinase have the same Km value and are inhibited in a partially competitive manner by ∈-aminohexanoic acid and aminomethylcyclohexanecarboxylic acid. They are also inhibited by cysteine and arginine, but are unaffected by iodoacetamide and p-chloromercuribenzoate. 5. On the basis of this and other evidence it is suggested that rabbit kidney cytokinase and human urokinase are similar, if not identical, enzymes.
The action of digitonin on rat liver mitochondria. The effects on enzyme content
Authors: Hoppel Charles , Cooper Cecil
Published: August 2015

1. The effects of repetitive treatment of rat liver mitochondria with digitonin were examined. The first treatment results in the removal of the outer membrane. Almost all the NADH–cytochrome c reductase (rotenone-insensitive) is lost whereas the major portions of the soluble and bound enzymes are retained. One exception appears to be the cytochromes, which undergo somewhat larger losses. The resulting inner-membrane complex carries out oxidative phosphorylation and Pi–ATP exchange. 2. The properties of the inner-membrane complex are affected by the osmoticity of the medium. When it is suspended in water little protein is lost but there is a marked loss of phosphorylation. If after the suspension in water the particulate fraction is reisolated by centrifugation and treated with digitonin, or if the aqueous suspension is treated directly with digitonin and the particulate fraction then reisolated, the phosphorylation is largely restored. 3. Additional treatment of the inner mitochondrial complex with digitonin results in the formation of a particulate fraction that contains approx. 8% of the initial mitochondrial protein, no outer membrane, no soluble mitochondrial enzymes and is still capable of coupled oxidative phosphorylation and Pi–ATP exchange. These effects cannot be reproduced by treatment with water. 4. The rat liver mitochondria and all of the resulting preparations obtained after digitonin treatment may be stored for long periods in dimethyl sulphoxide with little change of activity.
The action of digitonin on rat liver mitochondria. Electron microscopy
Authors: Morton Donald J. , Hoppel Charles , Cooper Cecil
Published: August 2015

1. Rat liver mitochondria were examined in the electron microscope by using negative staining in the presence of 0·3m-sucrose. The intact outer membrane does not appear to be freely permeable to the stain. Where the stain penetrated through a tear it was seen that the inner membrane had randomly oriented grooves, many of which contained round structures varying between 200 and 900å in diameter. Laminar structures containing two to five layers of approx. 50å each were found at the periphery. 2. When the outer membrane was removed by treating the mitochondria with digitonin several types of inner-membrane complexes were formed and they showed a general correlation with those observed in sectioned samples of the same preparations. The main types were: (a) a condensed form looking very much like the intact mitochondrion without the outer membrane (this still showed the grooves, some of which contained the round structures, and the laminar whirls at the edges); (b) a more transparent form containing tubules of uniform width and various lengths (some of these appeared to terminate in a hole at the surface of the inner membrane); (c) a large torn sac, probably the inner membrane, containing some tubules and vesicles. 3. When the inner-membrane complex was further treated with digitonin it was disrupted and the resulting material consisted of pieces of membrane, doughnut-shaped units and lamellar structures. Most of these pieces varied in size between 500 and 1000å.
Studies in phytosterol biosynthesis. Mechanism of biosynthesis of cycloartenol
Authors: Rees H H , Goad L J , Goodwin T W
Published: August 2015

1. The mechanism of cycloartenol biosynthesis in leaves of Solanum tuberosum was investigated with the use of [2−14C,(4R)-4−3H1]mevalonic acid. 2. The 3H/14C atomic ratio in cycloartenol was 6:6, the same as that in squalene; this eliminates lanosterol as a possible biosynthetic precursor of cycloartenol, and indicates that a hydrogen migration from C-9 to C-8 occurs. 3. Chemical isomerization of the cycloartenol to lanosterol (3H/14C ratio 5:6) and parkeol (3H/14C ratio 6:6) confirms the hydrogen migration from C-9 to C-8. 4. Possible mechanisms for the biosynthesis of cycloartenol and parkeol are discussed. 5. The 3H/14C ratio for 24-methylenecycloartanol was 6:6, demonstrating that the hydrogen atom at C-24 is retained during alkylation of the cycloartenol side chain.
The glycolipids of Lactobacillus casei A.T.C.C. 7469
Authors: Shaw N. , Heatherington K. , Baddiley J
Published: August 2015

1. The lipids were extracted from Lactobacillus casei A.T.C.C. 7469 with chloroform–methanol mixtures. The glycolipids were obtained by chromatography on silicic acid and DEAE-cellulose (acetate form). 2. Hydrolysis of the glycolipids with alkali gave two glycerol glycosides and a mixture of fatty acids. 3. The glycosides were separated and their structures elucidated. The major component was O-α-d-galactopyranosyl-(1→2)-O-α-d-glucopyranosyl-(1→1)-glycerol and the minor component O-α-d-glucopyranosyl-(1→6)-O-α-d-galactopyranosyl-(1→2)-O-α-d-glucopyranosyl-(1→1)-glycerol. 4. Analysis of the fatty acids by gas–liquid chromatography showed that they were predominantly palmitic acid, octadecenoic acid and lactobacillic acid.
Amino acid uptake in the developing chick embryo heart. The effect of insulin on glycine and leucine accumulation
Authors: Guidotti G. G. , Gaja G. , Loreti L. , Ragnotti G. , Rottenberg D. A. , Borghetti A. F.
Published: August 2015

1. The accumulation of [1−14C]glycine and the uptake, accumulation, incorporation (into protein, lipid, glycogen) and oxidation of l-[1−14C]leucine in 5-day-old chick embryo hearts were investigated in vitro, and the effects of insulin, puromycin and 4-methyl-2-oxopentanoic acid on these processes were studied. 2. With glycine, the ratio of concentration of the labelled amino acid in the cell water to that in medium markedly exceeded unity. Insulin significantly increased this ratio. Puromycin did not prevent the insulin effect. 3. With leucine, the concentration ratio of the labelled amino acid between intracellular and extracellular water approached unity in the absence of puromycin and was doubled by its presence. In neither case did insulin substantially alter this ratio. The addition of 4-methyl-2-oxopentanoic acid had no effect in the absence of insulin, but produced a significant increase of the concentration ratio in the presence of the hormone. 4. Leucine uptake was increased slightly by insulin in all experimental conditions except in the presence of puromycin, where a more pronounced stimulation was observed. The hormone had no effect on the incorporation of the labelled amino acid into protein, but accelerated its oxidation to carbon dioxide; the latter effect was particularly evident in the presence of puromycin and disappeared after the addition of 4-methyl-2-oxopentanoic acid.
Determination of oestrogen monoglucuronides by the Brown method
Authors: Blair H. A. F. , Kellie A. E.
Published: August 2015

In the Brown (Brown, 1955; Brown, Bulbrook & Greenwood, 1957) procedure for the determination of urinary oestrogens, losses may occur during the hydrolysis of the oestrogen conjugates and during the purification of the oestrogens thus formed. Losses during the latter stages were measured previously by adding free oestrogens to the hydrolysed urine. In the present study losses during acid and enzyme hydrolysis were measured by adding synthetic oestrogen monoglucuronides to urine.
Metabolic hydroxylations of trans-stilbene
Authors: Sinsheimer J. E. , Smith R. V.
Published: August 2015

1. A study was made of the hydroxylation of trans-stilbene in rabbits, guinea pigs and mice, as well as by rabbit liver microsomes. 2. In the rabbit in vivo, trans-stilbene is converted into 4-hydroxy-,4,4′-dihydroxy-,3-hydroxy-4-methoxy-and 4-hydroxy-3-methoxy-stilbene, and hydroxylation plays a more significant role in the metabolism of trans-stilbene than has previously been reported. 3. Investigation of the hydroxylation of 4-hydroxystilbene in the rabbit in vivo demonstrated its ready conversion into 4,4′-dihydroxystilbene and established its intermediacy in the formation of this compound and the methylated analogues of 3,4-dihydroxystilbene. 4. Hydroxylation of trans-stilbene in the guinea pig was found to follow a pattern similar, both qualitatively and quantitatively, to that in the rabbit. 5. Studies in the mouse revealed only limited yields of 4,4′-dihydroxystilbene. 6. Studies of the hydroxylation of trans-stilbene and 4-hydroxystilbene by rabbit liver microsomes located two of the reactions that occur with these compounds in vivo. 7. Work with a solubilized liver-microsomal preparation provided evidence that ‘stilbene hydroxylase’ activity is not completely lost on solubilization, thus allowing for future microsomal enzyme-isolation studies.
The deposition and metabolism of polyphosphoinositides in rat and guinea-pig brain during development
Authors: Sheltawy A. , Dawson R. M. C.
Published: August 2015

1. The deposition of triphosphoinositide and diphosphoinositide in rat and guinea-pig cerebral hemispheres during growth was measured. 2. The maximum increase in concentration of both of these phospholipids occurs during the period of myelination, but in the rat some di- and tri-phosphoinositide is present before significant myelination begins. 3. In guinea-pig cerebral hemispheres the polyphosphoinositides remaining after post-mortem breakdown are selectively enriched in dissected white matter compared with grey matter. 4. The polyphosphoinositides in the cerebral hemispheres of rats were labelled with injected 32P very rapidly; the specific radioactivities were in the order triphosphoinositide>diphosphoinositide>monophosphoinositide>total lipid phosphorus. 5. The synthesis of triphosphoinositide in rat forebrain occurs at an appreciable rate before, and at the start of, myelination, but the amount formed per gram of tissue is four to five times greater in adult rat brains, thus maintaining a constant turnover time (about 1hr.) for the whole triphosphoinositide fraction. This indicates that the rapid turnover of triphosphoinositide is independent of myelin deposition. 6. The specific radioactivity of the brain acid-soluble phosphorus pool referred to a constant dose of 32P/g. body wt. falls rapidly with age, reaching a minimum at 13–14 days, and then rises again. The specific radioactivities of the polyphosphoinositides reflect this change. 7. Part of the polyphosphoinositides in rat and guinea-pig cerebral hemispheres is rapidly hydrolysed post mortem leaving a stable portion resistant to further breakdown. 8. The rate and extent of post-mortem hydrolysis of the polyphosphoinositides in both species decrease with age. 9. After 32P labelling, the specific radioactivity of the triphosphoinositide remaining in the cerebral hemispheres of the rat after post-mortem breakdown is lower than the original triphosphoinositide fraction, suggesting two metabolically distinct pools.
Complex-formation between triphosphoinositide and experimental allergic encephalitogenic protein
Authors: Palmer F. B. , Dawson R. M. C.
Published: August 2015

1. Reactions between triphosphoinositide and the basic experimental allergic encephalitogenic (EAE) protein were examined in aqueous solution and in a biphasic solvent system (chloroform–methanol–water, 8:4:3, by vol.). 2. In the absence of salt an insoluble complex (I) is formed containing triphosphoinositide and EAE protein in proportions that represent complete neutralization of lipid and protein at the pH concerned. 3. In the presence of a low concentration (0·05m) of sodium chloride an insoluble positively charged complex (II) forms. It contains triphosphoinositide and EAE protein in a lower concentration ratio than complex I. This complex, which has a constant composition between pH7·5 and pH10, can take up additional micellar triphosphoinositide producing complex I, which can then be solubilized by excess of triphosphoinositide. 4. The complexes are dissociated by more concentrated sodium chloride solutions and low concentrations of calcium chloride, suggesting that they are largely stabilized by electrostatic bonds. The protein recovered after dissociation is immunologically active and has the same electrophoretic mobility as the original. 5. Water-insoluble ternary complexes containing triphosphoinositide, EAE protein and large amounts of phosphatidylcholine can be prepared. From these, chloroform–methanol (2:1, v/v) extracts only phosphatidylcholine. 6. An insoluble ternary complex of Ca2+ ion, EAE protein and triphosphoinositide can be prepared by adding calcium chloride to a complex I preparation solubilized by excess of triphosphoinositide. 7. EAE protein will also form complexes with other acidic phospholipids, e.g. phosphatidic acid, phosphatidylserine and phosphatidylinositol, but not with phosphatidylcholine or phosphatidylethanolamine. The phosphatidylinositol and phosphatidylserine complexes are chloroform soluble, i.e. proteolipids. 8. The possibility that complexes between EAE protein and acidic phospholipids occur in vivo is discussed. Triphosphoinositide and EAE protein occur in ox brain myelin in approximately the same concentration ratios as they do in complex II, formed at physiological salt concentration and pH.
The uptake of plasma constituents by the mammary gland of the sow
Authors: Spincer J. , Rook J. A. F. , Towers K. G.
Published: August 2015

1. Measurements were made of arterial and coccygeal concentrations of plasma constituents and of arteriovenous differences across the mammary gland in two anaesthetized lactating sows, and of coccygeal–mammary-venous differences in three conscious sows when lactating and again later when ‘dry’. 2. With the possible exception of acetate concentration, the compositions of arterial and coccygeal plasma were similar, and arteriovenous differences in the anaesthetized lactating sow corresponded closely to coccygeal–venous differences in the conscious animal. 3. In the ‘dry’ sow coccygeal–venous differences were in all instances small. 4. In the lactating sow there were large arteriovenous (or coccygeal–venous) differences (mean value as a percentage of arterial or coccygeal concentration) in glucose (31%), acetate (46%), arginine (27%), glutamate (42%), histidine (26%), isoleucine (36%), lysine (25%), leucine (39%), methionine (38%), phenylalanine (32%), proline (31%), threonine (22%), tyrosine (32%) and valine (27%), and in palmitate (19%), oleate (23%), linoleate (21%) and stearate (16%) of the plasma triglycerides. The values for the following constituents were in all instances small: β-hydroxybutyrate, acetone+acetoacetate, citrate, lactate, alanine, glycine, aspartate, palmitoleate of the plasma triglycerides, phospholipids, cholesterol, cholesteryl esters and free fatty acids. 5. Of the total recorded uptake of plasma constituents by the lactating gland, 59% was accounted for by glucose, 28% by amino acids, 11% by plasma triglycerides and 2% by acetate. The relative uptakes of glucose and amino acids were higher in the sow than values reported previously for the goat, and the relative uptakes of acetate and triglycerides much less.
The isolation of a component of the venom of Trimeresurus okinavensis that causes the aggregation of blood platelets
Authors: Davey M. G. , Esnouf M. P.
Published: August 2015

1. A substance has been isolated from the venom of the Okinawan pit viper (Trimeresurus okinavensis) that causes the aggregation of human blood platelets. The reaction resembles that between platelets and thrombin or connective tissue, in that the platelets release ADP. 2. The purified venom fraction is a protein–polysaccharide, and after Pronase digestion had mol.wt. 4×106, containing 10% peptide, 85% neutral sugars and 5% hexosamines. It is distinct from the proteolytic, esterolytic and coagulant materials also present in the venom, and has not been shown to possess any enzymic activity. How it reacts with platelets is not yet known.
Carbonic acid production and the role of carbonic anhydrase in decarboxylation in brain
Authors: Severinghaus John W. , Hamilton F. Norman , Cotev Shamay
Published: August 2015

Sudden oxygenation of a thin film of rat brain homogenate, suspended between the surface of a glass pH-sensitive electrode and a gas-permeable membrane, is accompanied by a fall in pH, which is greater when carbonic anhydrase is inhibited. The result suggests that oxidative decarboxylation yields carbonic acid (HCO3− and H+), which dissociates to form molecular carbon dioxide. Brain carbonic anhydrase facilitates the formation of carbon dioxide from the decarboxylation products.
‘Rapidly Appearing’ molybdenum electron-paramagnetic-resonance signals from reduced xanthine oxidase
Authors: Bray R C , Vänngård T.
Published: August 2015

Further electron-paramagnetic-resonance studies relating to the role of molybdenum in the enzymic mechanisms of xanthine oxidase were carried out. The classification of the various molybdenum signals obtained on reducing the enzyme is briefly discussed. The group of ‘Rapidly appearing’ signals, which are obtained with all substrates within the turnover time and which show interaction with exchangeable protons, were studied in detail. Signals with salicylaldehyde, purine and xanthine in H2O and in 95% D2O were examined at 9 and 35GHz and interpreted with the help of computer simulation. Molybdenum atoms in a number of different chemical environments are involved, each substrate giving rise to two superimposed spectra with slightly different parameters; g values and proton splittings were determined. The spectrum with salicylaldehyde is believed to represent the reduced enzyme alone not in the form of a complex with substrate and its two constituents are believed to represent the two molybdenum atoms bonded slightly differently within the enzyme molecule. With purine and xanthine the spectra are thought to represent complexes of reduced enzyme with substrate molecules. With xanthine one signal-giving species shows coupling to two equivalent protons, whereas in all the other species observed two non-equivalent protons are involved. The origin of the protons is discussed in the light of the direct hydrogen-transfer mechanism implicated earlier for the enzyme. It is concluded that the proton derived from the substrate is located at least 3å from the molybdenum atom with which it interacts.
Disequilibrium in the triose phosphate isomerase system in rat liver
Authors: Veech R. L. , Raijman L. , Dalziel K. , Krebs H. A.
Published: August 2015

1. The equilibrium constant at 38° and I 0·25 of the triose phosphate isomerase reaction was found to be 22·0 and that of the aldolase reaction, 0·99×10−4m. The [dihydroxyacetone phosphate]/[glyceraldehyde phosphate] ratio was found to be 9·3 in rat liver. The causes of the apparent deviation of the triose phosphate isomerase system from equilibrium in vivo have been investigated. 2. The equilibria of the triose phosphate isomerase and aldolase reactions were studied with relatively large concentrations of crystalline enzymes and small concentrations of substrates, approximating to those found in rat liver and muscle. There was significant binding of fructose diphosphate by aldolase under these conditions. There was no evidence that binding of glyceraldehyde phosphate by either enzyme affected the equilibria. 3. The deviation from equilibrium of the triose phosphate isomerase system in rat liver can be accounted for by the low activity of the enzyme, in relation to the flux, at low physiological concentrations of glyceraldehyde phosphate (about 3μm). It has been calculated that a flux of 1·8μmoles/min./g. wet weight of liver would be expected to cause the measured degree of disequilibrium found in vivo. 4. The conclusion that the triose phosphate isomerase is not at equilibrium is in accordance with the situation postulated by Rose, Kellermeyer, Stjernholm & Wood (1962) on the basis of isotope-distribution data. 5. The triose phosphate isomerase system is closer to equilibrium in resting muscle probably because of a very low flux and a high enzyme concentration. 6. The aldolase system deviated from equilibrium in rat liver by a factor of about 10 and by a much greater factor in resting muscle. 7. The measurement of total dihydroxyacetone phosphate and glyceraldehyde phosphate content indicates the concentrations of the free metabolites in the tissue. This may not hold for fructose diphosphate, a significant proportion of which may be bound to aldolase.
Hepatic collagenolytic activity in rats after carbon tetrachloride poisoning
Authors: Hirayama Chisato , Hiroshige Kaichiro , Masuya Tomiichi
Published: August 2015

1. Collagenolytic activity towards acid-soluble collagen labelled with [14C]-proline was assayed in rat liver with and without carbon tetrachloride poisoning. The products of enzymic digestion were found to be free amino acids and peptides. 2. The hepatic collagenolytic activity increased under conditions of single-dose and subacute carbon tetrachloride poisoning, and correlated with hydroxyproline content. The highest activity was found during recovery from subacute poisoning. 3. Under the same experimental conditions, hepatic acid-proteinase activity changed independently of the collagenolytic activity and also of hepatic hydroxyproline content. 4. The increased collagenolytic activity during carbon tetrachloride poisoning was found mainly in the supernatant fraction. 5. The ratio of the collagenolytic activity to hepatic hydroxyproline content increased during recovery from single-dose and subacute poisoning, and decreased during subacute poisoning.
Separation and identification of soluble nucleotides in cambial and young xylem tissue of Larix decidua Mill
Authors: Cumming Diane F.
Published: August 2015

The nucleotides present in the cambial tissue (primary wall tissue) and in the not yet fully differentiated secondary xylem (secondary wall tissue) of Larix decidua Mill. were extracted and characterized. The method of extraction best suited to the material was investigated and the problems involved in desalting of extracts and their effect on the final nucleotide pattern obtained are discussed. UDP-glucose was found to be the most important sugar nucleotide isolated from both cambial and young xylem tissue. UDP-galactose, UDP-arabinose, UDP-xylose, UDP-fructose, GDP-glucose, GDP-galactose, GDP-mannose, ADP-glucose, ADP-galactose, ADP-fructose, ADP-ribose and ADP-ribose phosphate (the last two compounds are the acid breakdown products of NADH and NADPH respectively) were also found in both extracts. UDP-galacturonic acid was identified only in the extract of the primary wall material. Several nucleotide oligosaccharides were obtained from both the extract of cambial tissue and that of the young xylem.