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At least 19 recordsLinked to original sources
PubMed1977

Ribonucleic acid from the higher plant Matthiola incana. Molecular weight measurements and DNA-RNA hybridisation studies.

The percentage of DNA from the crucifer Matthiola incana coding for different types of RNA was measured by filter saturation hybridisation experiments using RNA labelled in vivo. In addition, the melting curves of the various DNA - RNA hybrids formed and the buoyant densities of the DNA sequences complementary to different types of RNA were measured. 1. The RNA preparations used were 25, 18, and 5 S rRNA and 4 S RNA, purified by gel electrophoresis, and poly(A)-containing RNA purified by oligo-(dT)-cellulose chromatography. The molecular weights of the 25 S and 18 S rRNAs, calculated from the mobility in formamide-acrylamide gels relative to Escherichia coli RNA, are 1.25 - 10(6) and 0.64 - 10(6). The rRNA precursor has a molecular weight of approx. 2.1 - 10(6) and the average molecular weight of the poly(A)-containing RNA from both cotyledons and roots is 4 - 10(5). 2. The percentage of the genome, calculated on the basis of double-stranded DNA, coding for these RNAs and the estimated number of genes per haploid DNA amount are approximately 0.46% and 1100 for 25 S plus 18 S rRNA, 0.032% and 3600 for 5 S rRNA and 0.072% and 13 000 for 4 S RNA. In filter hybridisation experiments very little hybridisation of poly(A)-containing RNA was found. A rapidly-hybridising component is attributed to small amounts of contaminating rRNA. 3. M. incana DNA has a main band at 1.697 g - ml-1 in CsCl and a satellite constituting approximately 3% of the DNA, at 1.708 g - ml-1 - 25 and 18 S rRNA hybridise to DNA with a buoyant density of 1.701--2 g - ml-1. The buoyant density of 5 S DNA is slightly less at 1.700--1 g - ml-1. 4. S RNA hybridises to at least two separate regions, one within the main-band DNA and a second lighter component. None of the RNAs tested hybridised to the satellite DNA. The Tm of the DNA - RNA hybrids in 1 X SSC is 89 degrees C for 25 S rRNA, 85 degrees C for 5 S rRNA and 82 degrees C for 4 S RNA. 4. 5 and 4 S RNA preparations contain fragments which hybridise to sequences complementary to high-molecular-weight rRNA. This spurious hybridisation can be eliminated by competition with unlabelled high-molecular-weight RNA.

Base Sequence↗
PubMed1979

Effect of intralesional and systemic BCG-application or a combined cyclophosphamide/BCG treatment on experimental bladder cancer.

Infiltrating transitional cell carcinomas of the urinary bladder were induced by ingestion of 0.188% N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) in 145 female Wistar rats. After 8 months of carcinogen exposure, the animals were divided into different treatment groups. They received cyclophosphamide intraperitoneally as a single injection or BCG either once intralesionally or weekly subcutaneously or a combination of cyclophosphamide followed by subcutaneous BCG. The treatment effect was determined by body weight measurements and bladder tumour weight after 12 months. Compared with a control group statistically significant differences of bladder tumour weights were found after treatment with BCG alone or in combination with cyclophosphamide. Intralesional BCG resulted in an insignificant increase of tumour weights.

Animals↗
PubMedDate not supplied

Molecular size of the diapause hormone of the silkworm Bombyx mori.

The diapause hormone (DH) responsible for arrested development of the silkworm Bombix mori consists of two active principles of peptide (A and B). Since both hormones form aggregates in aqueous phases, the molecular weights were determined by gel permeation chromatography of Merckogel OR 6000 using methanol-dichloromethane mixture as the developing agent. Gramicidins and modified peptides soluble in the organic solvents were used as the standard markers for the molecular weight measurements of the hormones. The molecular weights of DH-A and -B are estimated to be 3300 +/- 400 and 2000 +/- 200, respectively.

Animals↗
PubMed1979

Thrombus weight as a measure of hypercoagulability induced by drugs.

Thrombus weight was used as a measure of the thrombus enhancing effect of drugs in 135 rats. The weight of thrombus formed in one hour, on a 20 x 0.5 mm platinum wire, inserted in the vena cava was taken as a measure of thrombosis. The change in thrombus weight which followed the injection of ellagic acid to activate the coagulation system, adenosine diphosphate to activate the platelets, and epsilon-aminocaproic acid to inhibit the fibrinolytic system, was measured. Pilot studies showed that the drug doses used brought about the appropriate changes in the factors named. The mean thrombus weight in 45 control animals was 1.93 mg. Ellagic acid increased it about five-fold, and epsilon-aminocaproic acid almost two-fold, while adenosine diphosphate reduced it by almost a half. Concurrent controls were used in each case. Clotting tests (whole blood clotting time, kaolin-activated whole blood clotting time, thrombin time, and partial thromboplastin time), performed at the end of the hour, showed no significant correlation with thrombus weight.

Adenosine Diphosphate↗
PubMed1979

Purification, characterization and localization of serine protease of Morris hepatoma 8999.

1. A serine protease of hepatoma 8999, isolated in the mitochondrial fraction, was purified and crystallized. The purified enzyme was apparently homogeneous on ultracentrifugal analysis and polyacrylamide disc gel electrophoresis. The ratio of absorbance at 280 nm and 260 nm, A280/A260, was 1.90 and its absorption coefficient, A280 1% was 10.5 cm-1 estimated from dry weight measurements. Its S20, w value was 2.23 S and its molecular weight was estimated to be 24000 +/- 1000. The enzyme contained twice as much lysine, arginine and histidine as chymotrypsinogen did, but had a very similar amino acid composition to serine protease from skeletal muscle. Its isoelectric point was pH 10.6. 2. The substrate specificity of the enzyme was the same as that of chymotrypsin A. Its Km and kcat values for N-acetyl-L-tyrosine ethyl ester, N-acetyl-L-phenylalanine ethyl ester and N-acetyl-L-tryptophan ethyl ester were 0.35 mM and 10.69 s-1, 0.38 mM and 10.7 s-1, and 0.11 mM and 11.8 s-1, respectively. Its activity was completely inhibited by phenylmethylsulfonyl fluoride and partially inhibited with tosylphenylalanine chloromethyl ketone. 3. The enzyme was shown to be located in different granules from the intracellular particules (light and heavy mitochondrial fraction) by sucrose density gradient centrifugation, and it was stained in mast cells of the hepatoma 8999 by the immunofluorescent technique. 4. Serine protease is present in different amounts in various organs of rat and the enzyme from hepatoma 8999 gave a single band that fused completely with those of the enzymes from skeletal muscle, heart, liver and kidney, respectively, on Ouchterlony double-diffusion analysis using antiserum to the crystalline enzyme of hepatoma 8999, but the enzyme from small intestine did not react with the antiserum.

Amino Acids↗
PubMed1977

Characterization of plasma low density lipoproteins on nonhuman primates fed dietary cholesterol.

LDL from animals of three nonhuman primate species, Macaca mulatta, Macaca fascicularis, and Cercopithecus aethiops, were studied. A standard preparation of 125I-LDL was added to isolated lipoprotein mixtures just prior to separation of plasma lipoproteins by agarose gel chromatography. A relative size index, rI, was determined by dividing the elution volume of the iodinated LDL by the elution volume of the sample LDL, both volumes being determined simultaneously during chromatographic elution. Comparison of rI with molecular weights measured by flotation equilibrium analysis in the analytical ultracentrifuge showed a linear relationship across a molecular weight range of 2.5-8.0 X 10(6), r = 0.985. A regression equation describing this relationship was used to calculate molecular weights of LDL from a group of M. fascicularis that were fed cholesterol-containing diets. In these animals, plasma cholesterol concentration ranged from 100 to over 700 mg/dl and was highly correlated with LDL molecular weight and with the micromolar concentration of the LDL. Using multiple regression analyses, the two variables of plasma LDL could be shown to account for 94% of the variation in plasma cholesterol concentration in the M. fascicularis of this study. Micromolar concentration and molecular weight of LDL were not correlated with each other, suggesting that in M. fascicularis at least two independent types of controls are operative in the response of plasma LDL to dietary cholesterol. The increase in LDL molecular weight was associated with a large increase in cholesteryl ester content and concomitant smaller increases in protein, phospholipid, and free cholesterol. As molecular weight increased, these components appeared to be added to the LDL particles together as discrete increments of fixed composition. The data are consistent with a spherical model of LDL structure with a core of cholesteryl ester and triglyceride and a 21.3 A-thick coat of phospholipid, free cholesterol, and protein.

Animals↗
PubMed1976

Retention of enzyme activity by detergent-solubilized sarcoplasmic Ca2+ -ATPase.

The Ca2+ -activated ATPase of sarcoplasmic reticulum can exist in true solution in the presence of some nonionic detergents, with retention of enzymatic activity for several days. The soluble active particles retain about 30 mol of phospholipid per mol of polypeptide chain even in the presence of a large excess of detergent, indicating the existence of relatively strong attractive forces between protein and lipid, as previous work from other laboratories has already suggested. Deoxycholate is much more effective than nonionic detergents in removing protein-bound lipid and, when used at solubilizing concentrations, completely delipidates and inactivates the ATPase. Preliminary molecular weight measurements indicate that the Ca2+ -ATPase exists as an oligomer in the native membrane: fully active enzyme in Tween 80 has a minimal protein molecular weight of about 400 000, corresponding to a trimer or tetramer of the ATPase polypeptide chain, and even the inactive enzyme in deoxycholate contains a substantial fraction of dimeric protein.

Adenosine Triphosphatases↗
PubMed1977

The purification and properties of NADP-dependent isocitrate dehydrogenase from ox-heart mitochondria.

The purification of NADP-linked isocitrate dehydrogenase from ox heart mitochondria is described. The molecular weight from gel filtration, sedimentation equilibrium and gel electrophoresis is 90000+/-4000, and there are two subunits in the molecule each of which binds NADPH with enhancement of the coenzyme fluorescence. The amino-acid composition is reported, and the absorption coefficient, A1/280%, estimated from dry weight measurements is 11.8 cm-1.

Amino Acids↗
PubMed1979

A re-evaluation of some basic structural and functional properties of Pseudomonas cytochrome oxidase.

Determinations of iron content and dry-weight measurements on samples of Pseudomonas cytochrome oxidase were coupled with sodium dodecyl sulphate/polyacrylamide-gel-electrophoresis studies of both the native protein and covalently cross-linked oligomers in order to estimate the enzyme's molecular weight and spectral absorption coefficients. A value of epsilon(ox.) (410)=282x10(3) litre.mol(-1).cm(-1) was calculated for a dimeric protein molecule having a total molecular weight of 122000 (based on iron analysis). Steady-state kinetic observations of the enzyme-catalysed oxidation of reduced azurin by nitrite indicated a marked increase in enzyme inactivation as the pH was raised from 5.7 to 7.2. Since NO, a product of the nitrite reductase activity of Pseudomonas cytochrome oxidase, is known to bind to the enzyme, a study was undertaken to try to assess the potential of NO as a product inhibitor. Investigations showed that samples of the oxidized protein at pH values 4, 5 and 6 bound NO to both haem c and d(1) components, but oxidized enzyme samples at pH7 and above formed their reduced ligand-bound forms when placed under an atmosphere of the gas. Ascorbate-reduced enzyme samples at pH4, 5, 6 and 7 were also found to bind NO at both haem components, although at pH7 the rate of haem c binding was very slow. At pH8 and 9 only the ferrohaem d(1) bound NO. Titration experiments on the reduced protein over the pH range 5-7, with nitrite as a precursor of NO, showed that the haem d(1) had a much higher affinity than the haem c: experiments at pH5.2 and 5.9 with NO-equilibrated solutions revealed the same pattern of behaviour with the oxidized enzyme.

Chemical Phenomena↗
PubMed1976

Naturally-occurring double-stranded RNA and immune responses. IV. Influence of molecular size on antigenicity and adjuvant activity.

The immunological properties of a naturally-occurring double-stranded ribonucleic acid (ds-RNA), obtained from a mycophage of Penicillium chrysogenum, have been studied in relation to molecular size. Materials of reduced size, as reflected by molecular weight measurements, produced by ultrasonication of native ds-RNA, exhibited progressively lowered ability to induce an anti-ds-RNA response in mice. Adjuvant and immunosuppressive activities were of similar magnitude in both high and low molecular weight fractions. Evidence was also obtained of increased toxicity in materials of reduced size.

Adjuvants, Immunologic↗
PubMed1979

Fractionation and structural elucidation of the active components of aurintricarboxylic acid, a potent inhibitor of protein nucleic acid interactions.

Commercially available, as well as synthetically prepared, samples of aurintricarboxylic acid (a widely employed potent inhibitor of protein nucleic acid interactions) consist mostly of a heterogeneous collection of polymers, as shown by fractionation schemes utilizing both dialysis and ultrafiltration, and by molecular weight measurements. 13C-NMR studies suggest that the polymeric material is of the phenol-formaldehyde type; inhibitory assays that depend on the formation of a protein-nucleic acid complex revealed that potency varied directly with the molecular weight of the polymer. Fractions of molecular weight 400 were essentially inactive.

Aurintricarboxylic Acid↗
PubMed1975

Exeriments for the production of graft-versus-host reaction in newborn mice by means of human immunocompetent cells.

It was not possible to produce the wasting disease in newborn mice by administering human leukocytes in Hanks' solution, or suspended in m-ATS or h-ATS. The attempt of the authors to produce immunosuppression by the administration of m-ATS started at newborn age-as a result of which the human immunocompetent cells would have produced serious GVH reaction-resulted only in a trend of GVH. The authors used only body weight measuring for detecting the GVH reaction. More sensitive parameters will be employed in their experiments in progress.

Animals↗