bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental allergic encephalomyelitis. Isolation of basic proteins and polypeptides from central nervous tissue
Authors: Carnegie P. R. , Bencina Beverley , Lamoureux G.
Published: August 2015

1. Basic protein (mol.wt. 16500) and polypeptides (mol.wt. 3500) were isolated from bovine spinal cord by a procedure involving defatting, acid extraction of the defatted material and repeated chromatography on Sephadex G-50. Similar fractions were isolated from guinea-pig brain. 2. These fractions produced experimental allergic encephalomyelitis in guinea pigs. 3. The polypeptides appeared to be derived from a basic protein of myelin as a result of the action of an acid proteinase during extraction with acid. Similar proteolysis might also occur in the isolation of other biologically active polypeptides from acetone-dried powders of nervous tissue. The activity of the acid proteinase was lowered by defatting with chloroform–methanol. 4. Peptides from tryptic digests of encephalitogenic polypeptides and protein were also encephalitogenic, which suggests that the encephalitogenic determinant may be quite a short sequence of amino acids. 5. These encephalitogenic polypeptides are further examples of antigens of low molecular weight.
Xanthine oxidase inactivation by reagents that modify thiol groups
Authors: Green R. C. , O'Brien P. J.
Published: August 2015

1. The presence of xanthine was required for the inhibition of bovine milk xanthine oxidase by o-iodosobenzoate, iodoacetamide, hydrogen peroxide or p-chloromercuribenzoate. 2. Inactivation by p-chloromercuribenzoate was very rapid, was reversed by cysteine and was less in the presence of FAD. Lineweaver–Burk plots showed that the inactivation by p-chloromercuribenzoate was competitive with substrate. 3. Inactivation by o-iodosobenzoate, iodoacetamide or hydrogen peroxide could not be reversed by cysteine or xanthine. However, the presence of xanthine during the incubation with inhibitor protected the enzyme against o-iodosobenzoate but not against iodoacetamide or hydrogen peroxide. 4. p-Chloromercuribenzoate protected the enzyme against inactivation by hydrogen peroxide.
Studies on the biosynthesis of protein and lipid components of rat liver mitochondria
Authors: Taylor C B , Bailey E. , Bartley W
Published: August 2015

1. Male rats were injected intraperitoneally with l-[35S]methionine, [32P]-phosphate and [2−14C]acetate. The animals were killed at various times up to 72hr. after injection, and liver mitochondria were prepared and fractionated into soluble protein, insoluble protein and lipid for assay of the radioactivity of each fraction. 2. The maximal specific radioactivity of total mitochondrial phospholipid with respect to both 32P and 14C was attained after approx. 6hr. 3. 32P was incorporated most rapidly into phosphatidylethanolamine, maximal incorporation being attained after approx. 6hr.; maximal incorporation into lecithin occurred after 6–12hr. The specific radioactivity of cardiolipin was still slowly increasing at the end of the experiment (72hr.). 4. There were no major differences between the rates of incorporation of 14C into the lecithin, phosphatidylethanolamine and cardiolipin fractions of mitochondrial phospholipid, maximal incorporation in each case occurring after approx. 6hr. 5. Maximal incorporation of 35S into both soluble and insoluble protein fractions was attained less than 12hr. after injection, the maximal specific radioactivity of soluble protein being higher than that of insoluble protein.
Effect of thyroidectomy on pathways of glucose metabolism in lactating rat mammary gland
Authors: Walters Eileen , McLean Patricia
Published: August 2015

1. Assessment of the overall metabolic changes in lactating mammary gland after thyroidectomy has been made by measurement of the incorporation of 14C from specifically labelled glucose, pyruvate and acetate into 14CO2 and 14C-labelled lipid in the experimental rats and in sham-operated control animals. 2. Thyroidectomy depressed the oxidation of 14C-labelled substrates, an effect still apparent when the control rats were pair-fed with thyroidectomized rats; however, the ratio of oxidation of [1−14C]glucose/oxidation of [6−14C]glucose was unaltered. In parallel with these studies it was revealed that the activities of hexokinase, glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADP-linked isocitrate dehydrogenase were all lower in the thyroidectomized group than in the pair-fed control group. 3. Thyroidectomy also lowered the incorporation of 14C-labelled substrates into 14C-labelled lipid, an effect further studied by measurement of the activities of citrate-cleavage enzyme and acetate thiokinase. Restricting the food intake of the control rats to that of the thyroidectomized group lowered the activity of citrate-cleavage enzyme, but no further depression was observed on thyroidectomy. The oxidized and reduced nicotinamide nucleotide content of mammary tissue was shown to be decreased in the thyroidectomized rats compared with the control rats.
A possible mechanism of inhibition of protein synthesis by dimethylnitrosamine
Authors: Villa-Treviño S.
Published: August 2015

1. The incorporation of [14C]leucine into liver proteins of rats was measured in vivo at various times after treatment of the animals with dimethylnitrosamine and was correlated with the state of the liver ribosomal aggregates. Inhibition of incorporation ran parallel with breakdown of the aggregates. 2. Inhibition of leucine incorporation into protein and breakdown of ribosomal aggregates were not preceded by inhibition of incorporation of [14C]orotate into nuclear RNA of the liver. 3. Evidence was obtained of methylation of nuclear RNA in the livers of rats treated with [14C]dimethylnitrosamine. 4. Zonal centrifugation analysis of radioactive, nuclear, ribosomal and transfer RNA from livers of rats treated with [14C]dimethylnitrosamine revealed labelling of all centrifugal fractions to about the same extent. 5. It is suggested that methylation of messenger RNA might occur in the livers of dimethylnitrosamine-treated rats and the possible relation of this to inhibition of hepatic protein synthesis is discussed.
Further studies on the stimulation of glycolysis by previous aerobiosis
Authors: Gaja G. , Ragnotti G. , Cajone F. , Bernelli-Zazzera A.
Published: August 2015

1. A short period of incubation in oxygen increases the rate of anaerobic glycolysis in all the normal adult tissues that have been tested, with the exception of erythrocytes. 2. This stimulation does not occur in the six different tumours and in the two embryonic tissues that have been studied. 3. In rat liver and in chicken heart, stimulation is first seen at birth. 4. Stimulation in rat liver slices is decreased in the presence of some inhibitors of oxidative metabolism (cyanide, Amytal, dinitrophenol, malonate), but is not affected if the aerobic preincubation is carried out at 1°. 5. The presence in the medium of some metabolites that are known to be important regulators of the glycolytic rate in living tissues has essentially no effect on stimulation. 6. The pretreatment of animals with inhibitors of oxidative metabolism and with antioxidants does not suppress stimulation; the observed effect of NN′-diphenyl-p-phenylenediamine is probably the consequence of the fall of the glycogen content in the liver. 7. The stimulation of anaerobic glycolysis by previous aerobiosis could not be demonstrated in liver homogenates.
Fatty acid synthesis in intestinal mucosa of guinea pig
Authors: Tame M. J. , Dils R.
Published: August 2015

1. Acetate–CoA ligase, acetyl-CoA–carbon dioxide ligase and fatty acid synthetase were shown to be present in particle-free fractions of guinea-pig intestinal mucosa. 2. Each of these enzymes was partially purified by ammonium sulphate precipitation from the particle-free supernatant. 3. The incorporation of acetate and citrate into fatty acid was measured. 4. Gas–liquid radiochromatography was used to investigate the pattern of fatty acids synthesized. 5. The rate-limiting step in fatty acid synthesis was shown to be acetyl-CoA–carbon dioxide ligase.
Changes in hepatic lipogenesis during development of the rat
Authors: Taylor C B , Bailey E. , Bartley W
Published: August 2015

1. Changes in the activities of ATP citrate lyase, ‘malic’ enzyme, glucose 6-phosphate dehydrogenase, pyruvate kinase and fructose 1,6-diphosphatase, and in the ability to incorporate [1−14C]acetate into lipid have been measured in the livers of developing rats between late foetal life and maturity. 2. In male rats the activities of those systems directly or indirectly concerned in lipogenesis (acetate incorporation into lipid, ATP citrate lyase and glucose 6-phosphate dehydrogenase) fall after birth and are maintained at a low value until weaning. After weaning these activities rise to a maximum between 30 and 40 days and then decline, reaching adult values at about 60 days. ‘Malic’ enzyme activity follows a similar course, except that none could be detected in the foetal liver. Pyruvate kinase activity is lower in foetal than in adult livers and rises to slightly higher than the adult value in the post-weaning period. Fructose 1,6-diphosphatase activity rises from a very low foetal value to reach a maximum at about 10 days but falls rapidly after weaning to reach adult values at about 30 days. 3. Weaning rats on to a high-fat diet caused the low activities of acetate incorporation, ATP citrate lyase, glucose 6-phosphate dehydrogenase and pyruvate kinase, characteristic of the suckling period, to persist. ‘Malic’ enzyme and fructose 1,6-diphosphatase activities were not altered appreciably. 4. No differences could be detected in hepatic enzyme activities between males and females up to 35 days, but after this time female rats gave higher values for acetate incorporation, glucose 6-phosphate dehydrogenase activity and ‘malic’ enzyme activity. 5. The results are discussed in relation to changes in alimentation and hormonal influences.
Nicotinamide–adenine dinucleotide-specific isocitrate dehydrogenase from pea mitochondria
Authors: Cox G. F. , Davies D. D.
Published: August 2015

1. A method of stabilizing the enzyme by using glycerol is described. 2. A purification procedure is presented giving a higher purification than previously described. 3. Data showing substrate activation and activation by citrate are presented. 4. Kinetic constants for NAD+, NADH and certain bivalent metal ions are given. 5. Pronounced inhibitory buffer effects are described. 6. A brief comparison between the NAD-specific isocitrate dehydrogenase from peas and that from other sources is made.
Structure and properties of rat thymus deoxyribonucleoprotein. Solubility properties and effects of precipitation
Authors: Itzhaki Ruth F.
Published: August 2015

1. Deoxyribonucleoprotein was prepared from rat thymus and was studied chiefly by the method of electric birefringence. The birefringence depends on the electrical and optical properties of the molecules and on their volume; the decay time of birefringence (after the removal of the electric field) depends on molecular length. 2. A comparison was made of the properties of deoxyribonucleoprotein redissolved after precipitation in 0·15m-sodium chloride with those of the original material, the main object being to find if structural changes have occurred in the former. As a preliminary, the dependence of the solubility of the deoxyribonucleoprotein on the concentration of added salt was investigated, and the birefringence properties were also studied after the addition of sodium chloride at low concentrations, after the alteration of pH and after dialysis. 3. It was found that precipitation of deoxyribonucleoprotein occurs in two fractions, beginning at about 0·4mm-sodium chloride. The solubility is minimal at about 0·15m-sodium chloride. 4. The electric birefringence and decay time of the deoxyribonucleoprotein decrease with increasing concentration of added sodium chloride, and the birefringence also decreases after dialysis. Prolonged dialysis leads to precipitation. 5. The properties of deoxyribonucleoprotein redissolved after precipitation with 0·15m-sodium chloride differ considerably from those of the original deoxyribonucleoprotein. This is attributed to some type of disorganization process occurring during precipitation. It is concluded that the organization of the original structure is very specific.
The extraction of cell walls of Pseudomonas aeruginosa with aqueous phenol. Material from the phenol layer
Authors: Clarke K. , Gray G. W. , Reaveley D. A.
Published: August 2015

1. A method is described for the fractionation of cell walls of Pseudomonas aeruginosa by using aqueous phenol. 2. With this technique, cell walls are quantitatively separated into five fractions: two water-soluble fractions (AqI and AqII), a residual insoluble fraction (R), and two phenol-soluble fractions (PhMP and PhMS). 3. The compositions of fractions PhMP and PhMS are discussed. Fraction PhMP consists almost entirely of protein, which is soluble in aqueous sodium dodecyl sulphate. Analytical ultracentrifugation of the solution yields a single peak, but several components may be resolved by gel electrophoresis. 4. Fraction PhMS consists principally of phospholipid (approx. 44%) and fatty acids (approx. 27%), although smaller amounts (approx. 13%) of protein are present.
The separation of vanillate o-demethylase from protocatechuate 3,4-oxygenase by ultracentrifugation
Authors: Cartwright N. J. , Buswell J. A.
Published: August 2015

1. Protocatechuate 3,4-oxygenase in the soluble part of a cell-free extract of Pseudomonas fluorescens (strain T) sedimented more rapidly than vanillate O-demethylase under specified conditions in a preparative ultracentrifuge. 2. The supernatant from this process contained vanillate O-demethylase and formaldehyde dehydrogenase, and when supplemented with NADH oxidized vanillate with an uptake of 1 mole of oxygen/mole of substrate and accumulation of protocatechuate. 3. This uptake was decreased to 0·5mole/mole of substrate in the presence of semicarbazide as trapping agent for formaldehyde. 4. Reasons are presented for the process of methyl group removal from vanillate being oxidative demethylation.
Assimilation of glucose carbon in subcellular rat brain particles in vivo and the problems of axoplasmic flow
Authors: Vrba R.
Published: August 2015

1. Rats were injected with [U−14C]glucose and the content of 14C in proteins and lipids of the cerebral P1 (‘nuclear’), P2 (‘mitochondrial’), P3 (‘microsomal’) and high-speed supernatant fractions was measured 7, 22 and 93hr. after injection of labelled glucose. 2. The crude brain mitochondrial fractions (P2) were subfractionated on continuous sucrose gradients (0·32–1·8m-sucrose) and the 14C content of the proteins and lipids of about 20 subfractions was measured. 3. About 40–50% of the 14C assimilated by brain proteins was found in the P2 (‘mitochondrial’) fraction. About 68–70% of the 14C assimilated by brain lipids was also recovered from the lipids of the P2 fraction. 4. Between 22 and 93hr. after injection of [U−14C]glucose both the amount of 14C in the protein of the P2 (‘mitochondrial’) fraction and the specific activity of this protein increased. The specific activity of the protein of all other particulate fractions (P1, P2 and P3) and subfractions (obtained from sucrose-density-gradient subfractionation of fraction P2) when related to the specific activity of the high-speed supernatant protein also increased during 93hr. after injection of [U−14C]glucose. The amount of 14C in the protein of the high-speed supernatant and the specific activity of this protein decreased during the same period. 5. The distribution of 14C in the lipids of all subcellular particulate fractions remained unchanged during the period 22–93hr. after injection of [U−14C]glucose. 6. It was concluded that a diffusion occurs of some supernatant proteins into subcellular particulate matter of the cerebrum and no significant preference for any subcellular particulate matter was observed. The lipids occur in the cerebrum mainly in a non-diffusible state, which is consistent with the view that they form almost entirely a part of the structure of the cerebrum. 7. The data obtained do not lend further support to the concept of axoplasmic flow within the cerebrum or the concept of a one-directional flow of mitochondria or other subcellular particles within the cerebrum.
The activity of uridine diphosphate glucose–d-fructose 6-phosphate 2-glucosyltransferase in leaves
Authors: Hawker J. S.
Published: August 2015

1. By using EDTA in reaction mixtures it was possible to determine the activity of sucrose phosphate synthetase in freshly prepared leaf extracts without the complications caused by sucrose phosphatase. 2. EDTA was found also to increase the activity of sucrose phosphate synthetase by as much as 100%. 3. High sucrose phosphate synthetase activities were found in leaf preparations in which sucrose phosphatase was inhibited by EDTA. By contrast with previous reports, the activities were sufficient to allow sucrose synthesis in leaves during photosynthesis to occur via sucrose phosphate. 4. Sugar-cane plants having different rates of photosynthesis also had different activities of sucrose phosphate synthetase in their leaves. 5. It is suggested that the activity of sucrose phosphate synthetase in leaves may play a role in the control of the rate of photosynthesis.
The C-terminal sequences of the heavy chains of human immunoglobulin G myeloma proteins of differing isotopes and allotypes
Authors: Prahl J. W.
Published: August 2015

The sequences of the C-terminal octadecapeptides obtained by cyanogen bromide cleavage of the γ-chains of myeloma proteins of the four subclasses, and a urinary heavy-chain-disease protein, have been determined. Although the sequences were markedly homologous, unique replacements were identified that distinguished between the γ2b, γ2c and γ2d subclasses. The data are in accord with the postulated existence of four genetic loci or cistrons, these having arisen by the process of gene duplication.
Amino acids in ram testicular fluid and semen and their metabolism by spermatozoa
Authors: Setchell B. P. , Hinks N. T. , Voglmayr J. K. , Scott T. W.
Published: August 2015

1. The testis of the ram secretes considerable amounts of amino acids (200μmoles/day) into the fluid collected from the efferent ducts. The principal amino acid in this testicular fluid is glutamate, which is present in concentrations about eight times those in testicular lymph or in blood from the internal spermatic vein. 2. The concentration of glutamate in seminal plasma from the tail of the epididymis is about ten times that in testicular fluid, and, though glutamate is the major amino acid in ejaculated seminal plasma, its concentration is less than in epididymal plasma. 3. After the intravenous infusion of [U−14C]glucose, labelled glutamate was found in the testicular fluid. Radioactivity was also detected in alanine, glycine, serine plus glutamine and aspartate. Alanine had the highest specific activity, about 50% of the specific activity of blood glucose. 4. When [U−14C]glutamate was infused, the specific activity of glutamate in testicular fluid was only about 2% that in the blood plasma. 5. Testicular and ejaculated ram spermatozoa oxidized both [U−14C]glutamate and [U−14C]leucine to a small extent, but neither substrate altered the respiration from endogenous levels. 6. No radioactivity was detected in testicular spermatozoal protein after incubation with [U−14C]glutamate or [U−14C]leucine. Small amounts of radioactivity were detected in protein from ejaculated ram spermatozoa after incubation with [U−14C]glutamate. 7. The carbon of [U−14C]glucose was incorporated into amino acids by testicular spermatozoa; most of the radioactivity occurred in glutamate.
Influence of reagents reacting with metal, thiol and amino sites of catalytic activity and l-phenylalanine inhibition of rat intestinal alkaline phosphatase
Authors: Fishman William H. , Ghosh Nimai K.
Published: August 2015

1. Studies on the inactivation of rat intestinal alkaline phosphatase by several metal-binding agents, namely EDTA, 8-hydroxyquinoline, pyridine-2,6-dicarboxylic acid, αα′-bipyridyl, o-phenanthroline and sodium cyanide, indicated the functional role of a metal, probably zinc, in the catalysis. The metal ligands lowered stereospecific uncompetitive inhibition of the enzyme by l-phenylalanine by an extent that paralleled the decline in enzyme activity. 2. The thiol reagents p-hydroxymercuribenzoate, iodoacetamide and iodine inactivated rat intestinal phosphatase. The enzyme could be protected from inactivation by either cysteine or substrate. The l-phenylalanine inhibition remained unchanged only in the presence of moderately inactivating concentrations of the thiol reagents. 3. Inactivation of the enzyme by the amino-group-blocking reagent, O-methylisourea, provided ample evidence for the participation in the catalysis of the ∈-amino group of lysine. At the same time, l-phenylalanine inhibition remained unaltered even when the enzyme was strongly inactivated. This ∈-amino-group-blocked enzyme exhibited no change in migration in starch gel, in contrast with enzyme treated with acetic anhydride, formaldehyde or succinic anhydride. The Michaelis constant of the enzyme was enhanced by such modifications, but the optimum pH remained the same. 4. d-Phenylalanine acted as a competitive or ‘co-operative’ activator for intestinal alkaline phosphatase after it had been modified by acetylation.
The binding of hydrogen ions to an acidic glycoprotein from bovine cortical bone
Authors: Peacocke A. R. , Williams P A
Published: August 2015

The H+ ion dissociation of bone sialoprotein in 0·2m-sodium chloride at 25° was studied. The total content of carboxyl groups available for titration was calculated by comparing the titration curve with the titration curves of three model systems and by the use of analytical data. This comparison showed that 7·0 carboxyl groups/mol. do not participate in the titration, and it is proposed that these are aspartic acid or glutamic acid carboxyl groups present as amides; this is also indicated by titration of the sialoprotein after acid hydrolysis. The titration of carboxyl groups was found to agree well with the Linderstrøm-Lang equation for spherical macroions.
The development of polysomes in the seed of Pisum arvense
Authors: Barker G R , Rieber M.
Published: August 2015

1. Ribosomal preparations from dormant seed, cotyledon and growing tissue from Pisum arvense were examined. 2. Polysomes were obtained from growing tissues under all conditions used. 3. Such particles were obtained from seed immediately after imbibition only when 5mm-zinc sulphate was included in the medium used for extraction. 4. No polysomes were obtained from dry seed. 5. Extracts of dry seed showed limited incorporation of phenylalanine into protein. 6. Extracts of seed after imbibition showed enhanced activity in incorporation of phenylalanine amounting to 72% of the activity found in extracts of growing tissue. 7. A nuclear fraction from dry seed was able to incorporate ATP into acid-precipitable material. 8. It is concluded that the protein-synthesizing system of the dry seed is limited by the low concentration of functional polysomes.
Development of gluconeogenesis in neonatal rat liver. Effect of premature delivery
Authors: Yeung D. , Oliver I. T.
Published: August 2015

1. An assay method for the determination of phosphopyruvate carboxylase activity is described in which improved sensitivity is obtained by separation of the enzyme from interfering pyruvate kinase by zone sedimentation. 2. The molecular weight of rat liver phosphopyruvate carboxylase determined by zone sedimentation is about 68000. 3. Premature delivery of rat foetuses by uterine section results in the rapid appearance of phosphopyruvate carboxylase, but hexose diphosphatase and pyruvate carboxylase, already present in the foetal rat liver, are not significantly affected, and glucose 6-phosphatase activity is only slightly affected. 4. The rate of incorporation of [14C]pyruvate into glucose by liver slices is also greatly increased by premature delivery and there is a highly significant linear correlation between this process and the phosphopyruvate carboxylase activity.
Biliary excretion of foreign compounds. Biphenyl, stilboestrol and phenolphthalein in the rat: molecular weight, polarity and metabolism as factors in biliary excretion
Authors: Millburn P , Smith R L , Williams R T
Published: August 2015

1. The extent of biliary excretion of biphenyl, tetralin, stilboestrol and phenolphthalein was studied in the rat. 2. Biphenyl and its 4-hydroxy and 4,4′-dihydroxy derivatives are extensively excreted in the bile as glucuronides in amounts increasing in order of molecular weight. 3. Stilboestrol and its glucuronide are excreted almost quantitatively in the bile mainly as the monoglucuronide, as are also phenolphthalein and its glucuronide. 4. Tetralin is excreted to the extent of about 13% of the dose, mainly as ac-tetralyl glucuronides. 5. The results and those of Abou-El-Makarem, Millburn, Smith & Williams (1967) are discussed and it is concluded that the extent of biliary excretion of foreign compounds in rats depends on their molecular weight and their possessing a strongly polar anionic group. There appears to be a minimum value of this molecular weight below which little biliary excretion (i.e. not more than 5–10% of the dose) occurs. There is some latitude in the choice of this molecular weight, which is about 325±50. The necessary molecular weight and polar group can be acquired by metabolism. Above this minimum value biliary excretion increases with molecular weight. It is suggested that the mechanism of the biliary excretion of foreign compounds may be similar to that of conjugated bile acids, which are highly polar and whose molecular weights exceed 400.
Biliary excretion in foreign compounds. Sulphonamide drugs in the rat
Authors: Millburn P , Smith R L , Williams R T
Published: August 2015

1. The extent of biliary excretion in the rat of 15 sulphonamide compounds was studied. 2. Most of the sulphonamides studied, with molecular weights from 172 (sulphanilamide) to 352 (N4-acetylsulphadimethoxine) are poorly excreted in the bile (0–4% of the dose), except sulphapyridine, sulphamethoxypyridazine and sulphadimethoxine. The last three are partly metabolized to glucuronides, whose molecular weights and polarities are such as to allow them to be excreted in the bile in appreciable amounts. 3. Succinylsulphathiazole and phthalylsulphathiazole are polar and have molecular weights (355 and 403) of an appropriate order, and are excreted unchanged in the bile in appreciable amounts. 4. Sulphadimethoxine N1-glucuronide (mol.wt. 487) is extensively excreted in the bile unchanged. 5. The results are examined in the light of the hypotheses put forward in the preceding paper (Millburn, Smith & Williams, 1967).
Biliary excretion in foreign compounds. Species difference in biliary excretion
Authors: Abou-el-Makarem M M , Millburn P , Smith R L , Williams R T
Published: August 2015

1. The biliary excretion of injected [14C]aniline, [14C]benzoic acid, 4-amino-hippuric acid and 4-acetamidohippuric acid in six or eight species of animal (rat, dog, hen, cat, rabbit, guinea pig, rhesus monkey and sheep) was studied. 2. These compounds, with molecular weights in the range 93–236, are poorly excreted in the bile in all the species examined and, in effect, there is little significant species difference in the extent of their biliary excretion. 3. Compounds of higher molecular weight (355–495) were also studied, namely succinylsulphathiazole, [14C]stilboestrol glucuronide, sulphadimethoxine N1-glucuronide and phenolphthalein glucuronide. 4. With these compounds a clear species difference in the extent of biliary excretion was found, the rat, dog and hen being good excretors, the rabbit, guinea pig and monkey poor excretors, and the cat and sheep taking an intermediary position. 5. There was a general trend for biliary excretion to be higher in all species when the compounds were of higher molecular weight. 6. These results are discussed in their relation to species differences in drug metabolism.
Biliary excretion of [14C]succinylsulphathiazole in the rat and rabbit
Authors: Abou-el-Makarem M M , Millburn P , Smith R L
Published: August 2015

1. After intravenous injection about 30% of the dose (20mg./kg.) of succinylsulphathiazole is excreted unchanged in the bile in 3hr. by the rat, whereas only about 1% is excreted by the rabbit. When the renal pedicles are ligated the biliary excretion of succinylsulphathiazole in the rat increases to about 80% of the dose, but in the rabbit under these conditions the biliary excretion is only 2% of the dose. 2. In the rat, the sulphonamide readily enters the liver and biliary excretion occurs against a concentration gradient from liver to bile; further, the excretory process can be saturated, and can be depressed by the simultaneous administration of phenolphthalein glucuronide or bile salts. 3. In the rabbit, these conditions have not been found; succinylsulphathiazole does not readily enter the liver from the plasma, there is no transfer of the drug from the liver cells to the bile against a concentration gradient, and no saturation or depression of the biliary excretion of succinylsulphathiazole is found. 4. It is suggested that two factors responsible, at least partly, for the low biliary excretion of succinylsulphathiazole in the rabbit are the poor entry of the sulphonamide into the liver in this species and a deficiency of the concentrative mechanism for its excretion in the bile.
The tissue content and turnover rates of intermediates in the biosynthesis of glycosaminoglycans in young rat skin
Authors: Hardingham T. E. , Phelps C. F.
Published: August 2015

1. The tissue contents of hexose monophosphate, N-acetylglucosamine 6-phosphate, UDP-glucose, UDP-galactose, UDP-N-acetylglucosamine, UDP-N-acetylgalactosamine and UDP-glucuronic acid were determined in the skin of young rats less than 1 day post partum. Tissue-space determinations were used to calculate their average cellular concentrations. 2. The incorporation of [U−14C]-glucose into the intermediates was recorded with time and their rates of turnover were calculated. The results demonstrated product–precursor relationships along the pathway of hexosamine synthesis and that of hexuronic acid synthesis. The rates of synthesis of UDP-N-acetylhexosamine and UDP-glucuronic acid were 1·5±0·3 and 0·24±0·03mμmoles/min./g. of tissue respectively. These results indicated the average turnover time of the total tissue glycosaminoglycans to be about 5 days.
The distribution of monoamine oxidase and α-glycerophosphate dehydrogenase in pig brain
Authors: Tipton K F , Dawson A P
Published: August 2015

Activities of the enzymes monoamine oxidase (EC 1.4.3.4), α-glycerophosphate dehydrogenase (EC 1.1.99.5) and cytochrome oxidase (EC 1.9.3.1) were determined in homogenates and in the mitochondrial fraction prepared from individual regions of pig brain. The variation in the activity of α-glycerophosphate dehydrogenase paralleled that of cytochrome oxidase, but this was not the case with monoamine oxidase. The differences in the activities of the enzymes among homogenates of the various regions of the brain persisted in mitochondria prepared from these homogenates. The purification of these three enzymes paralleled each other when mitochondria were prepared, suggesting that the three enzymes are bound to the same particles.
The mechanism of glucose 6-phosphate–d-myo-inositol 1-phosphate cyclase of rat testis. The involvement of hydrogen atoms
Authors: Barnett J. E. G. , Corina D. L.
Published: August 2015

Comparison of the initial 3H/14C ratios in specifically labelled d-glucose 6-phosphates with the final ratios in myo-inositol produced by glucose 6-phosphate–d-myo-inositol 1-phosphate cyclase from rat testis showed that, during the conversion, the hydrogen atoms at C-1 and C-3 were fully retained, one hydrogen atom was lost from C-6, and that at C-5 was apparently retained to the extent of 80–90%. The loss of 3H could not be stimulated by addition of unlabelled NADH, and when unlabelled substrate was used 3H from [3H]NADH and [3H]water was not incorporated. Treatment of the enzyme with charcoal abolished the activity, and this was restored to 25–50% of the original activity by NAD+. The charcoal-treated enzyme again apparently gave 85% retention of hydrogen with [5−3H]glucose 6-phosphate as substrate in the presence of NAD+ alone, but the retention was decreased to 65% with excess of NADH. The results are interpreted as indicating that the cyclization proceeds by an aldol condensation in which C-5 is oxidized by NAD+ in a tightly-bound ternary complex, and that the apparent loss of 3H when untreated enzyme is used is due to an isotope effect. It is suggested that after treatment with charcoal some exchange of NADH with an external pool may take place.
Alkaline haematin and nitrogenous ligands
Authors: Gallagher W. A. , Elliott W. B.
Published: August 2015

1. Pyridine reacts with alkaline haematin to form a dipyridine dihydroxy dimeric haematin in which there is no competition between pyridine and OH− for coordination positions on the iron of haematin. 2. Imidazole competes directly with OH− to form the monomeric imidazole parahaematin in alkaline media. 3. The monomeric imidazole parahaematin aggregates readily to form a species that is precipitated on standing. 4. A structure is proposed for the haematin–pyridine compound in alkaline media.
Plasmalogenase activity in normal and demyelinating tissue of the central nervous system
Authors: Ansell G B , Spanner Sheila
Published: August 2015

1. The plasmalogenase activity of brain was found to be associated with the white matter but was absent from myelin fractions. 2. Increased enzyme activity was found in demyelinating spinal cords from vitamin B12-deficient monkeys and in white matter from a patient with multiple sclerosis.
A protein component of the cell surface of Staphylococcus aureus
Authors: James A. M. , Brewer J. E.
Published: August 2015

1. Treatment with trypsin of cells of Staphylococcus aureus strain Cowan I, known to carry a protein component that includes the Jensen protein A, results in an increase in the negative mobility of the cells at pH values greater than 6. 2. Similar treatment of cells of strain Wood 46, which has no surface protein component, causes no change in the electrophoretic mobility. 3. Electrokinetically heterogeneous populations are observed in two strains of S. aureus, one of human and the other of animal origin. Evidence is presented ascribing this to the presence of varying amounts of protein components on the surface of different cells.
Excitatory acidic amino acids and the cation content and sodium ion flux of isolated tissues from the brain
Authors: Harvey J. A. , McIlwain H.
Published: August 2015

1. Sample from the neocortex and piriform cortex of guinea pigs and rats were incubated in inulin-containing glucose–saline. Their intracellular (non-inulin) space contained 19–27μequiv. of Na+/g. of original tissue. These values were stable between 30 and 100min. after incubation commenced, but addition of 22NaCl to the neocortical samples showed them to be associated with a flux of 400μequiv. of Na+/g. of tissue/hr. 2. Addition of 0·5–10mm-l-glutamic acid or 0·1mm-N-methyl-dl-aspartic acid rapidly increased the tissue's Na+ content; N-acetyl-dl-aspartic acid was without action. 3. During the first 1–1·5min. after the addition of l-glutamic acid to neocortical samples their Na+ content increased at 600μequiv./g. of tissue/hr., and the rate of 22Na+ influx corresponded to 1230μequiv. of Na+/g./hr. These rates were calculated to be sufficiently rapid to account for loss of the tissue's normal membrane potential within 1–2sec. of the addition of the acid. 4. In addition, a rapid but more limited loss of K+ took place after the addition of l-glutamic acid or the methylaspartic acid; on continued incubation tissue K+ content increased, as also did the intracellular volume of the tissue, from its original 670μl./g. to 1100μl./g. 5. Interpretation of these and of associated changes is offered in terms that involve a cation pump and the permeability changes associated with the nerve impulse.
The bacterial transformation of abietic acid
Authors: Cross B. E. , Myers P. L.
Published: August 2015

An Alcaligenes species, which was isolated from soil, can utilize abietic acid as its sole carbon source. During growth, the bacterium transforms abietic acid into 5α-hydroxyabietic acid (I, R=OH), a product considered to be 7β-hydroxy-13-isopropyl-8ξ-podocarp-13-en-15-oic acid (II, R=H) and a compound, C20H28O3, which is believed to be an epoxy-γ-lactone.
The role of ubiquinone in the respiratory chain of Acetobacter xylinum
Authors: Benziman Moshe , Goldhamer H.
Published: August 2015

1. Whole cells of Acetobacter xylinum were found to contain a quinone of the ubiquinone (coenzyme Q) group. The quinone was isolated from the cells and crystallized. It was identified by its physical, chemical and spectroscopic properties as a ubiquinone with 10 isoprene units (ubiquinone-10). No naphthaquinone was detected in the cells. 2. Cell-free extracts prepared by means of a French pressure cell were separated into three fractions by differential centrifugation. The ubiquinone was located predominantly in the particulate fraction sedimenting at 33000g, which also contained most of the NADH oxidase and malate oxidase activities. The concentration of ubiquinone-10 in extracts was similar to that of the flavoproteins and about three times the concentration of the individual cytochromes. 3. Aerobic incubations of crude extracts with either NADH or malate resulted in reduction of the endogenous ubiquinone-10 to steady-state concentrations of 55 and 40% of the total quinone respectively. In the presence of cyanide more than 95% of the endogenous ubiquinone-10 was reduced by either NADH or malate. 4. The initial rate of reduction of endogenous ubiquinone-10 by malate and the rate of ubiquinol oxidation, in A. xylinum extracts, were found to be compatible with the overall rate of malate oxidation with oxygen. 5. The effects of various respiratory inhibitors on the oxidation–reduction reactions of the endogenous quinone indicate that its position on the respiratory chain is between the malate flavoprotein dehydrogenase and the cytochrome chain.
Metabolism of phospholipids and the characterization of fatty acids in bovine corpus luteum
Authors: Scott T. W. , Hansel W. , Donaldson L. E.
Published: August 2015

1. Phosphatidylcholine was the predominant phospholipid in bovine corpora lutea; it accounted for about 50% of the total phospholipid phosphorus. Phosphatidylethanolamine (13%) and ethanolamine plasmalogen (8–9%) were the next two major components. 2. After incubation of the tissue with [32P]orthophosphate the total radioactivity and specific radioactivity of phosphatidylinositol were higher than those of any other lipid. 3. Luteinizing hormone failed to increase significantly the incorporation of [32P]orthophosphate into total phospholipids from luteal tissue slices, but did stimulate progesterone synthesis and lactate production. 4. The proportion of oleate (18:1) in the neutral lipids and phospholipids was higher than that of any other fatty acid. 5. The proportion of unsaturated fatty acid in the tissue lipids exceeded 60%, and almost half of this was polyunsaturated. Arachidonate (20:4), docosatetraenoate (22:4) and docosapentaenoate (22:5) were the principal polyunsaturated fatty acids. 6. After incubation of luteal tissue with [1−14C]acetate, the greatest proportion of radioactivity in the fatty acids isolated from the total lipid fraction was in palmitate (16:0) and docosatetraenoate (22:4). Polyunsaturated fatty acids accounted for almost 50% of the 14C radioactivity incorporated and this pattern was observed in phospholipids, triglycerides and free fatty acids.
Activity and intracellular distribution of enzymes of ketone-body metabolism in rat liver
Authors: Williamson D. H. , Bates Margaret W. , Krebs H. A.
Published: August 2015

1. The activities of hydroxymethylglutaryl-CoA synthase and lyase in rat liver were found to be two- to 15-fold greater than those reported by other authors under similar conditions. 2. When expressed on the basis of body weight, no appreciable differences were found between the activities of hydroxymethylglutaryl-CoA synthase in whole homogenates of livers from normal and starved rats. The synthase activity increased by 70% and 140% in livers of alloxan-diabetic rats and rats fed on a high-fat diet respectively. 3. Hydroxymethylglutaryl-CoA lyase activity showed no significant increases in starvation or alloxan-diabetes, but a 40% increase was found in fat-fed rats. 4. Less than 12% of the activities of both enzymes were found in the cytoplasmic fraction of normal liver. The cytoplasmic activity doubled in alloxan-diabetes and starvation; on feeding with a high-fat diet the increase, though significant, was less marked. 6. The intracellular distribution of glutamate dehydrogenase indicated that the changes in the cytoplasmic activities observed were not due to leakage from the mitochondria. 7. Feeding with a normal or high-fat diet after 48hr. starvation caused within 24hr. a decrease in the cytoplasmic activity of hydroxymethylglutaryl-CoA synthase to values lower than those found in rats fed on a corresponding diet for a longer period of time. 8. Acetoacetyl-CoA deacylase activity in liver was about 20% of that of hydroxymethylglutaryl-CoA synthase and was primarily located in the cytoplasm. Starvation or alloxan-diabetes did not alter the acetoacetyl-CoA deacylase activity. 9. It is concluded that variations in the concentrations of enzymes involved in acetoacetate synthesis play no major role in the regulation of ketone-body formation in starvation and alloxan-diabetes. The changes in the cytoplasmic activities of hydroxymethylglutaryl-CoA synthase and lyase suggest that acetoacetate synthesis can occur in the cytoplasm. This may play a role in the disposal of surplus acetyl-CoA arising in the cytoplasm when lipogenesis is inhibited.
The activities of the citric acid-cycle enzymes in rat bone-marrow cells
Authors: Goldwasser Eugene
Published: August 2015

The activities of the eight citric acid-cycle enzymes of rat bone-marrow cells were determined along with several other mitochondrial and non-mitochondrial enzymes. Four of the citric acid-cycle enzymes (aconitase, succinyl-CoA thiokinase, α-oxoglutarate dehydrogenase and succinate dehydrogenase) have closely similar low activities; two [isocitrate dehydrogenase (NAD) and citrate synthase] have intermediate activities; the remaining two (malate dehydrogenase and fumarase) have high activities. The other enzymes surveyed also exhibited a spread of three orders of magnitude, the mitochondrial enzymes showing no less variation than the others.
Metabolism of phospholipids by spermatozoa and seminal plasma
Authors: Scott T. W. , Dawson R. M. C.
Published: August 2015

1. The hydrolysis of added 32P-labelled phospholipids by whole ram and bull semen and the separated spermatozoal and plasma components was examined. 2. The ethanolamine phosphoglycerides were rapidly attacked by washed spermatozoa, forming predominantly glycerylphosphorylethanolamine, but with whole semen and seminal plasma a lysophosphatidylethanolamine was also detected. 3. The hydrolysis of lecithin by spermatozoa and plasma was very slow, and glycerylphosphorylcholine was the sole product detected. 4. Ram testicular spermatozoa were comparatively inactive in metabolizing both phospholipids, but ampulla contents showed the same activity as ejaculated semen. 5. Phosphatidylinositol was metabolized by spermatozoa obtained from any portion of the ram reproductive tract and also by seminal plasma. With testicular components, ampulla contents and washed ejaculated spermatozoa, inositol monophosphate, an unidentified phosphate ester and inorganic phosphate were the main products. In contrast, with whole semen and seminal plasma, glycerylphosphorylinositol was the predominant water-soluble phosphate ester. 6. Accessory-gland secretion obtained from vasectomized rams showed a pronounced phospholipase A activity towards ethanolamine phosphoglyceride. 7. On aerobic incubation of whole ram semen there was a decrease in the concentration of all phospholipid classes, although cardiolipin showed the greatest percentage decrease. In the choline phosphoglyceride fraction, this loss was confined to the plasmalogen component. This breakdown of phospholipids was decreased considerably when the spermatozoa were washed, and was not observed when whole bull semen was incubated under similar conditions.
Microsomal ring-fission of cis- and trans-acenaphthene-1,2-diol
Authors: Hopkins R P
Published: August 2015

1. The ring-fission of cis- and trans-acenaphthene-1,2-diol by rat liver microsomes was studied. 2. 1,8-Naphthalic acid was detected and isolated after microsomal incubations of the diols. 3. The accompanying reduction of NAD+ was followed spectrophotometrically. 4. The optimum pH for the microsomal reaction was 9·4 for the oxidation of the cis-diol and 9·8 for that of the trans-diol. 5. p-Chloromercuribenzoate and 2,4-dichlorophenol inhibited the reaction. 6. Possible mechanisms for the microsomal ring-fission, involving 1,8-naphthalic aldehyde, are discussed.
Methods for the separation and identification of mycobactins from various species of mycobacteria
Authors: White A. J. , Snow G. A.
Published: August 2015

A single pure component was isolated from mycobactin P by countercurrent distribution; its side chain is n-cis-octadec-2-enoyl; its purity and molecular structure were confirmed by mass spectrometry of its aluminium complex. The separation of ferric and of aluminium complexes of mycobactins by thin-layer chromatography is described. Mycobacterium terrae, M. marinum and M. smegmatis produce mycobactins that differ among themselves and from mycobactins P and T. A nomenclature for the mycobactins and their derivatives is suggested.
A spectrophotometric study of the denaturation of deoxyribonucleic acid in the presence of urea or formaldehyde and its relevance to the secondary structure of single-stranded polynucleotides
Authors: Cox R A , Kanagalingam K
Published: August 2015

1. The thermal denaturation of DNA from rat liver was studied spectrophotometrically. In sodium phosphate buffers denaturation led to a single-stranded form having, at 25°, about 25% of the hypochromism of the intact double helix. 2. The hypochromism of the denatured form was the same in 1mm- as in 10mm-sodium phosphate buffer and was scarcely affected by reaction with formaldehyde. The hypochromism was decreased by about 40% in the presence of 8m-urea. 3. The hypochromism of denatured DNA at low ionic strengths was about the same as that of fragments of reticulocyte ribosomal RNA that were too short to form double-helical secondary structure and about the same as that of RNA after reaction with formaldehyde. 4. The spectrum of DNA was slightly affected by the presence of 8m-urea or 4m-guanidinium chloride. The differences in the spectrum of the native and denatured forms of DNA in 0·1m-sodium phosphate buffer, in 8m-urea–10mm-sodium phosphate buffer and in 4m-guanidinium chloride–10mm-sodium phosphate buffer, pH7·6, were similar but not identical. 5. Denatured rat liver DNA appears to have no double-helical character at 25° in 10mm-sodium phosphate buffer, pH7·6; increasing the buffer concentration to 0·1m leads to a more compact form in which about 40% of the residues form base pairs.