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A linear lattice of equivalent binding sites with nearest neighbor cooperativity is used as a basic model for a linear biopolymer displaying cooperative binding of small ligands. Complicating effects due to the dimerization of free ligands are taken into account. The theory implies two types of intrinsic binding processes: (1) the binding of an isolated ligand (nucleation), and (2) the binding of a ligand in the immediate neighborhood of an already bound one (aggregation). The ratio of the respective association constants determines the degree of cooperativity. It is generally shown how the equilibrium properties of the system can be derived by means of the matrix method. Sonic properties of special practical significance, such as the equilibrium concentrations of free and bound monomer ligands, are discussed in more detail. On the basis of a pertinent kinetic model chemical relaxation of strong cooperative bindinng is also examined. The paper gives particular emphasis to the formulation of quantitative relations which are most useful for an experimental application of the the oretical results. Appropriate procedures to plot measurable data and to evaluate basic parameters are proposed. They are applied to specific experimental systems in a subsequent set of papers. [ABSTRACT FROM AUTHOR]

This paper describes the presence and amounts of free glucose, hexosamine and hexuronic acid in the gingival exudate. Exudate was sampled on filterstrips from individuals with different degrees of gingival inflammation. The strips were weighed before and after absorption of exudate and the exudate was calculated. The exudate was extracted and the content of glucose, hexosamine and hexuronic acid was determined colorimetrically. In keeping with previous studies the amount of exudate increased with the severity of inflammation. Exudate glucose varied between 1.13 and 7.09 µg/mg exudate. The hexosamine content was approximately 0.6 µg/mg and the hexuronic acid concentration varied between 50 and 60 µg/mg. The possible sources of origin of the carbohydrate components are discussed. [ABSTRACT FROM AUTHOR]

The activities of five enzymes were determined by flurometric micromethods on epidermal tumors (basal and squamous cell epithelioma, keratoacanthoma and verruca seborreica) and compared to the activities in the adjoining, apparently normal epidermis. All activities were higher in the tumoral tissues. [ABSTRACT FROM AUTHOR]

Chemical investigation of the glycosidic constituents of Oospora virescens (Link) Wallr. resulted in the isolation of several glycosides. We have shown recently that two of them, named virescenoside A (I) and B (II) are β-D-altropyranosides of virescenol A and B; these diterpenic aglycones have been found to have the structure of isopimaradien-α,3β-19-triol (JV) and isopimaradien-3β,19-diol (V), respectively. In this paper we describe the isolation and structure of virescenoside C, a new metabolite of Oospora virescens. The results obtained show that virescenoside C (IIIa), C26K40O7, m. p. 160-162°, [α]D -71,4Y°, is a β-D-altropyranoside of virescenol C, which is found to have the structure of 3-keto 19-hydroxy isopimaradiene (VIa). These results are based on physical evidence (infra-red, nuclear magnetic resonance and mass spectra) and particularly on the chemical correlation with virescenol B and virescenoside B. Virescenoside C seems to be the third example of an altroside found in nature, [ABSTRACT FROM AUTHOR]

About 70 strains of white and brown rot fungi were cultivated on media, containing filter paper cellulose as the main carbon source. The cellulolytic activity of the culture filtrates was measured after different periods of growth by means (if the turbidimetric method. The results obtained indicate a difference between the two types of wood decay fungi as to the capacity of attacking the cellulose used in the medium and in the cellulase test. No significant C1-activity was found injury of the brown rot cultures whereas all white rot fungi tested exerted a measurable activity on the test substrate. The effect of various carbohydrates and some proteins as inducers of cellulase activity was studied. Especially cellobiose and lactose were active on white rot fungi in this respect, particularly in the presence of yeast extract. Also some brown rot fungi exerted C1-activity after incubation on glucose or cellobiose. [ABSTRACT FROM AUTHOR]

The article discusses the laboratory experiments in molecular evolution and efforts to explore the presence or absence of life on planets in the solar system. It states that the paper aims to present some of the salient aspects of laboratory investigation and suggest the origin from a geological matrix of compounds and systems preceding cells. The demonstrations helped in resolving the fundamental dilemma on how cells are yielded from primitive protein when cells themselves have been generally held to be necessary to produce protein. It suggests that the experiments contributed in filling a new rigor into the theory of spontaneous generation.

In the accompanying paper, we present evidence to show that the biosynthesis of the two characteristic polypeptide constituents ‘A’ and ‘B’ of the crystal protein toxin of Bacillus thuringiensis car. tolworth, is restricted to a short interval, from 16–18 h, in the mid-stationary phase of the growth cycle of 24 h in culture. Here we examine the question of the kinetics of biosynthesis of the corresponding crystal protein messenger RNA. We have taken the direct, approach of assaying a series of RNAs isolated from B. thuringiensis cultures at varying times of culture for messenger activity in a heterologous Escherichia coli, subcelular system. The product of RNA-stimulated protein synthesis in vitro was characterized by immunoprecipitation with anti-serum against purified crystal protein and by polyacrylamide-gel electrophoresis of the antigen-antibody precipitates dissolved in the detergent sodium dodecylsulfate. RNA from B. thuringiensis, but not that of Bacillus cerens, stimulates the synthesis of protein which specifically precipitates with crystal protein antiserum. The time of extraction of RNA from B. thurinrjgiensis does not appear to be critical in determining its messenger activity : all samples taken in the interval of 11–20 h contained messenger RNA for crystal protein by the criterion of specific immunoprecipitation. In each case a significant proportion of the synthesized protein migrated in the region of the smaller-molecular-weight component A (55000) of the crystal protein in the electrophoretic separation. However, hardly any synthesized protein co-migrated with the larger-molecular-weight component B (120000) of this protein. Since all the labelled protein precipitated by the crystal protein antiserum was larger than about 15000 molecular weight we conclude that mainly large fragments of the crystal protein were synthesized in the E. coli system. We failed in our attempts to isolate polysomes as a source of messenger RNA from stationary-phase ceils. Thus it was not possible to determine by experiments similar to those described above whether the crystal protein messenge is stored in ribosomes or in some other fraction of the cell when it is not being translated. [ABSTRACT FROM AUTHOR]

An IgG1 type of protein with the genetic marker combination Gm(f), non a, and (x) has been described. The evidence from studies on isolated IgG1 Fc fragments showed that the IgG1 protein was of normal size. No Gm markers other than the three mentioned were found. Thus, there was no evidence for deletions or duplications giving rise to the unusual IgG1 protein. In contrast, the origin of the unusual genetic marker combination appears to be a rare IgG1 gene Gmf non a, x, probably due to an intragenic recombination at the IgG1 cistron. [ABSTRACT FROM AUTHOR]

A theoretical analysis of the crossover theorem is presented based on a linear approximation. Cases are considered in which the simple crossover theorem may lead to erroneus conclusions. Among them are the following: more than one interaction site of an effector with the enzymatic chain; influx and efflux of metabolites regulated by outer metabolic processes; existence of inner effectors; conservation equations for metabolite concentrations; and changes of the state of complexes with the metabolites. It is shown that the action of an effector does not always produce a crossover at the affected enzyme. On the other hand, examples are given where "pseudo-crossovers" occur at unaffected enzymes. It is concluded that, for real systems the identification of the interaction sites of an effector with an enzymatic chain cannot be achieved by the simple crossover theorem. Furthermore, even the identification of "rate controlling" or "regulatory important" enzymes by means of crossovers must, be done with great caution. A simple and general procedure for the identification of interaction sites of an outer effector with an enzymatic chain is proposed. It requires the determination of the flux through the chain, the concentrations of the substrates and products of the enzymatic step under consideration and the rate law by which an inner effector, if present, influences the reaction rate of this step. [ABSTRACT FROM AUTHOR]

If an aqueous solution of [32P]phosphate is shaken with a chloroform-extract of rat liver mitochondria, the label is bound specifically by a number of chloroform-soluble proteins. Several chloroform-soluble proteins contain free SH-groups, as indicated by the binding of [14C]ethacrynate, a specific reagent for SH-groups. One fraction of chloroform-soluble proteins binds phosphate in high amounts, and this binding of phosphate is specifically inhibited by SH-reagents. Among various labeled anions (phosphate, malate, citrate, glutamate and ADP) only phosphate was shown to be bound at a significant amount by a chloroform-extract of rat liver mitochondria. [ABSTRACT FROM AUTHOR]

This article focuses on the paper "The Influence of Tri-Iodothyroacetic Acid on the Circulating Lipids and Lipoproteins in Euthyroid Men With Coronary Disease," by B. Strisower, J.W. Gofman, E.E. Gallioni, J.H. Rubinoer, J. Pouteau and P. Guzvioh that was published in a 1957 issue of the periodical "Lancet."

The article focuses on the paper "The Skin of Hairless Mice: The Formation of Cysts and the Distribution of Lipids," by W. Montagna, H.B. Chase and H.P. Melaragon. The isolated disorientated fragments pursue their evolution in the direction of sebaceous gland parenchyma which presently forms cysts. This process together with the chemistry of the lipoids concerned is the subject of this clear and readable account. The paper is illustrated with some unnecessary and completely unhelpful microphotographs.

Two methods of fractionating the protoplasmic proteins of potato tubers are described, the first based primarily on filtration, the second primarily on highspeed centrifugation. By the first method it was shown that proteins increase about 20 per cent when tuber-halves are transferred from +3 to +26°C for 10 days during late fall and decrease about 10 per cent during a similar transfer in summer. Tubers kept constantly at +26°C showed a steady drop in protein content, which became more rapid as soon as sprouting was initiated. A similar initial drop occurred during three successive years on transfer to +3° C, but after a few weeks either the original protein content was largely regained or at least the drop was markedly slowed up as compared with tubers at +26° C. Differences between fractions associated with sprouting are indicated. By the second method it was shown that conversion of tubers from the dormant to the active state by transfer from +3° to +26° C for 10 days resulted in a large decrease in mitochondria, microsomes and acid-insoluble proteins, whereas the globulins and acid-soluble albumins remained unchanged. The changes in the first three fractions decreased as the tubers came out of their rest period. These changes associated with sprouting are essentially in agreement with the changes found by the first method. A comparison of the two methods indicates that method 2 yields a more nearly complete extraction and a better separation of the fractions. [ABSTRACT FROM AUTHOR]

The presence of some amino acids and nucleic acid derivatives in the exudates from peas and roots of pea seedlings was demonstrated with the aid of appropriate, nutritionally deficient Ophiostoma mutants. A combined chromatographic and microbiological technique enabled a quantitative determination of certain nucleic acid constituents in the exudates from excised roots of pea seedlings. The amounts exuded from each root (dry weigh: 5.0 mg) during five hours in distilled water were: adenine 1.5 μg, guanine 1.3 μg, and uridine + cytidine 2.0 μg. These substances cannot be assumed to account for more than c. 25 per cent of the UV-absorbing material moving in the chromatogram, and c. 6 per cent of the total amount of UV-absorbing material present in the exudates. [ABSTRACT FROM AUTHOR]

The article discusses drug metabolism research. Drug metabolism is not limited to measuring drug absorption and determining the chemical structure of the metabolites. According to the author, there are many objectives in drug metabolism research. He discusses various aspects of drug metabolism. It is stated that the frequent ingestion of foreign chemicals in the drug form required the evolution of a biological process that was successful in preventing the accumulation of toxic substances. It is also stated that when a special mechanism is absent that can prevent the efficiency of a chemical with a low lipid solubility, the result could be different.

The article provides information on the study "Further Observations on Factors Which Influence the Water Content of the Stratum Corneum," published in the 1953 issue of the "Journal of Investigative Dermatology." This sort of work is of fundamental importance to the practical dermatologist who should have very little excuse for not reading this excellent paper in the original. But, it has been commented that when the author states that the effect of the thickness of a keratin slab on the rate of diffusion through it does not follow Fick's law he must tell the reader what he means. Similarly if he writes of adsorption of water by amino imidiazone and guanidyl polar groups in the protein molecule he should change to the familiar and commonly accepted word absorption for the mere imbibition of water by an organ such as the stratum corneum.

In confirmation of Maximov's earlier results, non-penetrating (sucrose) and penetrating (dimethylsulfoxide) substances lowered the frost killing temperature from -6°C in the control to -41° to -24°C, depending on the concentration. In contrast to his results, neither glycerol nor CaCl2 provided as good or as consistent protection. The addition of 0.05 M mercaptoethanol overcame this protective effect either completely (low concentrations of protectant) or partially (high concentrations). The effect of the mercaptoethanol occurs during freezing and not during thawing. Since ethanol, without the mercapto-(SH) group, does not counteract the protective effect, such protection must be related in some way to the sulfhydryl group - perhaps by an effect on the disulfide and sulfhydryl groups of the proteins. [ABSTRACT FROM AUTHOR]

This article presents information on the research paper "Autosensitivity to Deoxyribonucleic Acid," by M.B. Levin and H. Pinkus. The paper reports that crops of wheals, erythema and eechymoses, attributed to abnormal sensitivity to DNA, are prevented by chloroquine.

Cereal plants were grown for 3 weeks under sterile conditions in solution culture with their roots either unrestricted or growing between glass ballotini. The exudation of both amino acids and carbohydrates was increased when the roots were grown through a solid medium and the total quantity exuded was equivalent to about 9% of the dry matter increment of the roots. [ABSTRACT FROM AUTHOR]

The article focuses on the role of antibody in T-cell responses. In the article the evidence is marshaled for an overall hypothesis according to which many of these activities of the T cell can be explained in terms of passively acquired antibody. In this context it must be said at once that T cells do not appear to carry much Ig. The sensitive lacto-peroxidase technique, by which surface proteins can be iodine-labeled in situ, has demonstrated IgM on thymus and thymus-derived cells in some hands.

The inbred LOU/Wsl rat strain presents a high incidence of spontaneous ileocoecal immunocytoma which secrete monoclonal immunoglobulins. These tumours are transplantable in histocompatible animals and their secreting properties are maintained over many passages. A screening of monoclonal immunoglobulins secreted by 250 such tumours revealed sixty-three proteins which shared class-specific determinants, physico-chemical features and biological properties different from those of rat IgM, IgA, IgG1, IgG2a, IgG2b and IgG2c classes, and characteristic of proteins of the IgE class. [ABSTRACT FROM AUTHOR]

A "periplasmic" maltose binding protein was purified from Escherichia coli. This protein is shown to be under the same positive control as the whole maltose system, and its synthesis is inducible by maltose. This binding protein is coded by malE, one of the three cistrons of the malB region involved in the transport of maltose. The binding characteristics of this protein, as well as the kinetics of release of bound maltose, suggest that the binding protein can exist in two states differing by their affinity towards maltose. The significance of this result is discussed in view of the role that the protein is believed to play in maltose transport. [ABSTRACT FROM AUTHOR]

Application of the two-dimensional polyacrylamide gel electrophoretic procedure recently described by Mets and Bogorad [4] to the resolution of Escherichia coli ribosomal proteins is described. This procedure is fast (running time of 8-10 h) and highly sensitive (1-2 µg protein per spot) and it gave good resolution for the majority of the 55 proteins in E. coli ribosomes. Moreover, the method has permitted the resolution of a large number of high-molecular-weight. proteins associated with ribosomes not exposed to high-salt washing. Using purified proteins, the positions in the electrophrogram of the individual proteins of the 30-S subunit have been determined. [ABSTRACT FROM AUTHOR]

1. A fraction (G2) which contained 30% of the total non-collagenous proteins was prepared from neutral EDTA extracts of bovine cortical bone. Three hitherto undescribed proteins (G2Bglycoprotein, G2C-glycoprotein, G2CF) were identified in this fraction together with collagen, serum albumin, immunoglobulin G and transferrin. 2. The G2B-glycoprotein was prepared from the G2 fraction and shown to be homogenous by electrophoretic and immunochemical criteria. 3. The G2B-glycoprotein was demonstrated to be present in bovine plasma at a concentration of approximately 20 mg/100 ml. It was found that in the collagenase digest of decalcified bone matrix the ratio of the G2B-glycoprotein concentration to the serum albumin or immunoglobin G concentration was upto 250 times higher than the ratio in plasma. 4. The G2B-glycoprotein contained approximately 78% protein, 4% sialic acids, 3% hexosamines and 14% neutral sugars, and had an apparent molecular weight, of around 50 000. [ABSTRACT FROM AUTHOR]

The CO binding properties of monomeric (Hb III and IV), dimeric, and tetrameric Chironomus haemoglobins as well as of the monomer-analogue valence hybrid (α2Mmet βmet βdeoxy) of Hb M Iwate were studied and compared with the respective O2 binding properties. All these haemoglobins show hyperbolic O2 binding curves and a Bohr effect. The amplitudes of the O2 Bohr effect curves range from Δlog pO2(½) = 0.3 (Hb III) to 2.4 (tetrameric Chironomus haemoglobin). The ligands CO and O2 differ not only in affinity but also with regard to the Bohr effect. The CO affinities of the various Chironomus haemoglobins are 60 to 490 times larger than the O2 affinities and the amplitudes of the CO Bohr effect curves are 1.25 to 8 times smaller than those of the respective O2 Bohr effect curves. In the case of Hb M Iwate, however, the CO Bohr effect is larger than the O2 Bohr effect by the factor 1.25 (2,3-bisphosphoglycerate-reacted Hb M) and 1.4 (stripped Hb M). The ligand-specific differences in the magnitude of the Bohr effect cannot be explained solely by the allosteric interaction connected with the trans-effect of the complex. The differences are discussed in terms of steric influences on the binding geometry of the 6th ligand by protein side chains at the distal side of the haem group.

The dynamics of the single-strand conformation changes of oligo- and polyriboadenylic acids has been investigated by a fast temperature-jump technique. Chemical rexalation processes have been observed in the range of 0.1 to 1 μs. The relaxation times are independent of the nucleotide concentration and also do not depend upon the pit within the range 6.9 to 9.2. The amplitudes correspond to those expected from thermal melting curves, According to these results the relaxation is assigned to the “single-strand helix-to-coil” transition. Measurements af different wavelengths show that the relaxation times observed in the spectral range 240 nm to 270 nm are different from those observed around 285 nm by a factor of 2 to 3. This result demonstrates that the “helix-coil” transition of adenylic acid chains cannot be described by a simple all-or-none model with two reaction states. As expected for a single-strand helix-coil transition there is a relatively small ionic strength dependence: a decrease of the salt concentration leads to an increase of the relaxation time. At high ionic strengths of monovalent ions (1 M and more) the appearance of relaxation times at 5 to 10 μs and in the ms range seem to indicate aggregation. The presence of Mg2+ leads to a strong decrease of the amplitude around 285 nm, whereas the amplitude around 245 nm remains almost unchanged; the time constant of the 245-nm relaxation increases with increasing Mg2+ concentration. Apparently Mg2+ ions induce a specific shift of the riboadenylic acid chain conformation. Measurements of the temperature dependence in the range of 0 to 50 °C revealed an increasing rate of the conformation change with increasing temperature. The relaxation process measured around 245 nm is characterised by a higher apparent activation enthalpy than that measured around 285 nm. The relaxation behaviour found for the polymer is also shown by oligoriboadenylic acids. The chain length dependence of the relaxation times is relatively small. The difference of the relaxation behaviour observed around 245 nm and around 285 nm extends to the dimer. Thus the observation of two different relaxation times cannot be explained by a cooperative effect. The relaxation time constants observed for oligo- and polyriboadenylic acids indicate the existence of energy barriers in the conformational transition. Similar time constants have been observed previously for the elementary process of base pairing in adenylic-uridylic acid double helices. The observation of two relaxation time constants for the conformation change of riboadenylic acid chains demonstrates the existence of more than two different conformation states. [ABSTRACT FROM AUTHOR]

This article focuses on a study related to the in vitro sensitivity of blastomyces dermatitidis to six diamidine derivatives. Difficulties arise from the instability of solutions, their intolerance of heat, adsorption of the drug by filter paper, incompatibility with nucleic acids and, in general, the materials used for the enrichment of culture media that is necessary for propagation of the yeast phase.

The sixth (C′6), seventh (C′7) and eighth (C′8) components of human complement were separated from each other by chromatography on hydroxyl apatite and obtained in functionally pure form. Density gradient ultracentrifugation revealed that C′6 and C′7 interact with the fifth component of complement (C′5) to form a reversible protein-protein complex. Evidence was obtained that this complex occurs also in unfractionated, fresh human serum. Kinetic analysis of the reaction sequence in immune haemolysis disclosed that C′5, C′6 and C′7 act, in this order, subsequent to the third component (C′3) and prior to C′8. Exploration of the mode of action of C′5, C′6 and C′7 led to the formulation of two alternative hypotheses. The three components act either sequentially or as one functional unit. Their fluid phase interaction, the shape of dose-response curves and the encountered difficulty to isolate intermediate reaction products favour the concept that they act as a functional unit. [ABSTRACT FROM AUTHOR]

Discusses a study which examined the maximum histamine response of denervated fundic pouches in dogs. Methods of histamine administration; Effect of histamine on gastric secretory inhibition; Analysis of acid output from a heidenhain pouch following the subcutaneous injection of histamine acid phosphate.

Citrate lyase has been shown to have values for SO20,w and DO20,w of 17.6 S and 3.02 x I0-7 cm² sec-1, respectively. Using the Svedberg equation a value of 533000 was assigned for the molecular weight of the active preparation. The meniscus depletion sedimentation equilibrium methyl led to a value of 550000 while the transient state method gave a value of 566000, The partial specific volume was determined by the ²H2O method of Edelstein and Sohachman to be 0.73 ml g-1. The enzyme was also studied in a variety of denaturing solvents. Molecular weights were measured in the analytical ultracentrifuge and also using dodecylsulphate-polyacarylamide-gel electrophoresis with marker proteins of known molecular weight. A range of particles resulted suggesting that there could be 16 sub-units in the active enzyme preparation. [ABSTRACT FROM AUTHOR]

The article discusses tentative rules for carbohydrate nomenclature. In 1964, the Commission on the Nomenclature of Organic Chemistry of the International Union of Pure and Applied Chemistry (IUPAC) formed a Special Committee on Carbohydrate Nomenclature to consider the existing Anglo-American Rules of Carbohydrate Nomenclature and to prepare a set of IUPAC Rules for Carbohydrate Nomenclature. These Rules are now issued jointly by the IUPAC Commission on the Nomenclature of Organic Chemistry and the IUPAC-IUB Commission on Biochemical Nomenclature.

The analysis of a monoclinic crystal modification of L-asparaginase from Eseherichia coli supports the chemical and physico-chemical evidence for a tetrameric subunit structure. The pseudo-symmetries occurring in the crystal structure provide evidence that the molecules lie on positions with approximate point symmetry 222. [ABSTRACT FROM AUTHOR]

The physicochemical properties and circular dichroism of bovine erythrocyte cupro-zinc protein were investigated. In sedimentation velocity experiments in the ultracentrifuge, the protein sedimented as a single peak with an s°20, w of 3.06 S. The diffusion coefficient was 8.27 F, the partial specific volume 0.736 ml/g, and the intrinsic viscosity 0.033 (g/100 ml)-1. Combination of these hydrodynamic data indicated a molecular weight near 33000, which was in good agreement with chemical and gel filtration data. Them olecular weight was also determined by the sedimentation equilibrium method using interference optics. By this method Mw was 33500, and the protein appeared to be homogeneous. The circular dichroism spectrum of bovine erythrocyte cupro-zinc protein was unique among copper proteins in having positive contributions at 610, 440 and 350 nm, which disappeared on removing the metal atoms. In the ultraviolet there were positive contributions near 260, 270 and 290 nm, and removal of the metal atoms changed these into negative contributions at 265 and 285 nm and a positive contribution at 295 nm. Possible assignments of these bands are discussed. In the far ultraviolet, the circular dichroism spectra of the native protein and apoprotein showed few differences, indicating that the metal atoms do not play a dominant role in determining protein conformation. However, urea had a profound effect on the circular dichroism of the apoprotein butl ittle effect on that of the native protein. Neither the native protein nor the apoprotein showed the double minimum between 200 and 220 nm characteristic of α-helix, but rather the existence of a minimum at 210 nm suggested that the proteins contained some β-pleated sheet structure. Reduction and carboxymethylation of thiol groups greatly reduced the ultraviolet circular dichroism, indicating that the disulphide bridges have a strong influence in determining the tertiary structure of the protein. [ABSTRACT FROM AUTHOR]

Gas chromatography-mass spectrometry and radio-gas chromatography were used to identify metabolites of [14C]cortieosterone and [14C]pregnenolone in faeces and urine from germfree and conventional male rats. The metabolites were generally more polar than those in female rats and the main part of those which could be identified were found in the free steroid fraction. In the conventional male rats a number of pregnane-3,11,16,20,21-pentol isomers constituted the major corticosterone metabolites identified both in urine and i_n faeces. In addition 3α(and 3β),20β-dihydroxy-5α-pregnan-11-one and 5α-pregnane-3α(and 3β),11β,20,21-tetrol were excreted in faeces. In the germfree male rats, minor amounts of some C19O3a and C21O3 steroids were excreted as monosulphates in faeces. However, 5α-pregnane-3α(and 3β),11β,20β,21-tetrols were the predominant steroids in this fraction. These compounds also constituted the major part of steroids identified in the disulphate fraction, which also contained 3α(and 3β),11β,21-trihydroxy5α-pregnan-20-one. All radioactive steroids excreted in the urine of germfree male rats were unconjugated. Although none of these compounds could be fully identified evidence was obtained for the presence of several C19O5, C21O4, C21O5, C21O6 and C21O7 steroids. The findings are discussed in relation to previous information on the steroid metabolizing activities of the intestinal flora and sex differences in the metabolism of steroids in rats. [ABSTRACT FROM AUTHOR]

Legumin from broad bean seed has been carboxymethylated and analysed. The protein contained three N-terminal residues, leucine, glycine and threonine. Three polypeptide chains were found by polyacrylamide gel electrophoresis of the dissociated protein; their molecular weights were 56000, 42000 and 23000. 140 peptides were found on fingerprints of tryptic digests of S-carboxymethyl-legumin. Of these 14 were radioactive in digests of [14C]carboxymethylated legumin, and 16 were radioactive in digests of legumin prepared from material labelled in vivo with [35S]sulphate. Three new end groups were found after cyanogen bromide cleavage corresponding to Met-Val, Met-Phe and Met-Pro sequences. Taken in conjunction with the amino acid analyses these peptide mapping experiments suggest that the protein contains a total sequence weight of 115000, which is in agreement with the finding of three polypeptide chains whose weights total 121000. On the basis of dye binding studies and of the incorporation in vivo of uniformly 14C-labelled amino acid mixture, it is suggested that the polypeptide chains of molecular weights 56000, 42000 and 23000 are present in molar ratios of 1:4:6 or 1:3:6, respectively. From consideration of experimental accuracy the 1:3:6 structure is preferred. The proposed 10 chains model for legumin has a molecular weight of 320000. [ABSTRACT FROM AUTHOR]

Discusses the abbreviations and symbols for the description of nucleic acids, polynucleotides and their constituents. Nucleotide coenzymes and related substances; Use of systematic three-letter symbols; Polymerization equation.

The distribution of intraperitoneally administered [4-14C]pregnenolone and [1,2-3H]corticosterone were studied in male and female conventional rats at different times after injection of the isotopes. The administered steroids were rapidly excreted into the intestinal tract; 2 h after administration 60-70% of the given dose was localized in the small bowel, mainly in monosulphurylated form. the elimination in urine and faeces of intraperitonelally administered [4-14C]pregnenolone and [1,2-3H]corticosterone was studied in germfree and conventional, male and female rats. The steroids were excreted as free and conjugated metabolites. The latter were mainly monosulphurylated, and to a smaller extent disulphurylated. No steroid glucuronides were found. As a probable result of the intestinal microbial sulphohydrolase activities conventional rats excreted more free steroids than germfree both in faeces and urine. Male rats excreted more unconjugated and more polar steroids than female. Corticosterone metabolites were monosulphurylated to a larger extent than pregnenolone metabolites; faecal excretion of corticosterone metabolites was quantitatively more important than of pregnenolone metabolites. [ABSTRACT FROM AUTHOR]

1. The interaction between poly(C) and guanylic monomers (guanosine, Guo-5'-P, Guo-3'-P and Guo-2'/3'-P) at millimolar concentrations was investigated by optical methods. 2. All monomers formed complexes of stoichiometry of 1 guanosine for 2 cytidines although under sensibly different conditions: while guanosine, Guo-3'-P and Guo-2'/3'-P formed complexes stable over several pH units, the interaction between poly(C) and Guo-5'-P is only stable within 0.1 pH units. The reasons for this surprising behaviour must be searched for in a conformation of Guo-5'-P which differs from the other guanyl monomers. 3. All complexes observed follow cooperative binding. The interactions are only stable in the presence of a large excess of monomer. Nearest neighbour interaction energies computed are found to be between 2 and 3 kcal/mole, sensibly lower than found in polymer interactions. 4. From the results presented it appears that the poly(C)-guanyl monomer complexes have similar or identical geometry as poly(C) + poly(G) at acid pH. [ABSTRACT FROM AUTHOR]

1. The oral antidiabetic glycodiazine (2-benzene sulfonamido-5-β-methoxyethoxy pyrimidine), an inhibitor of hepatic lipolysis, was used to investigate the metabolic role of liver lipid in glucogenesis in the perfused livers of fasted (24-30 h) rats. In a concentration of 10 mM, glycodiazine inhibited almost completely endogenous ketone body formation. 2. Perfusion with pyruvate as substrate, in the presence of glycodiazine, resulted in a higher rate of pyruvate oxidation and suppressed the rate of glucose synthesis in comparison to livers perfused with pyruvate alone. Thus, maximal rates of gluconeogenesis from pyruvate would seem to require an adequate supply and oxidation of fatty acids. 3. Oleate, even in the presence of glycodiazine, stimulates glucose synthesis from pyruvate. Uptake of and ketone body formation from oleate were also not affected by glycodiazine. These results allow the conclusion that glycodiazine specifically inhibits liver lipolysis. 4. Glucagon (57 nM), although having no significant effect on gluconeogenesis from pyruvate at this concentration, overcame the inhibitory effects of glycodiazine on glucose formation and suppressed the elevated pyruvate oxidation which results from the inhibition of endogenous lipid mobilization. 5. Glucagon, in the absence of added substrates, stimulated gluconeogenesis, urea production and ketogenesis. The increase in gluconeogenesis due to glucagon was not impaired by glycodiazine. This indicates that intermediates arising from fatty acid oxidation do not limit the rate of gluconeogenesis under these conditions. [ABSTRACT FROM AUTHOR]

Parenteral administration of folio acrid to rats produces marked increases in the rates of synthesis of protein, RNA and DNA in the kidney. Basic nuclear protein synthesis in increased within 1 hour of folate administration with a sharper increase appearing about 18 hours and reaching a maximum about 26 hours. RNA synthesis increases to reach a maximum at 12 hours after folate before declining to normal levels at 24 hours. The increase in the rate of DNA synthesis commences at about 18 hours and reaches a maximum, about 20 times above control levels, about 32 hours after folate. Using the increased rate of DNA synthesis normally seen 26 hours after folate as a reference point, actinomycin D was found to produce a very marked depression of DNA synthesis when administered between 0 and 4 hours after folate; at longer time intervals this depression became less marked and when actinomycin D was given at 20 hours no effect was observed. Actinomycin D, given at the same time as folic acid, also abolished, the increase in the rate of RNA synthesis normally seen 12 hours after folate. In contrast to the tinge dependent effect of actinomycin D, cycloheximide produced a similarly profound decrease in the rate of DNA synthesis, measured 26 hours after folate, when the drug was given at any time between 0 and 25 hours after folate. These results suggest that the complete requirement for increased RNA synthesis has been met by the time that increased DNA synthesis begins at 18 hours after folate administration, but that there is continuous need for newly synthesised protein both before and during the period of increased DNA synthesis. [ABSTRACT FROM AUTHOR]

Complex I, a complex consisting of 1 RNA strand and 6 protein subunits of the icosahedral RNA-phage fr was formed. The protein subunits bind on more than one site to the RNA. Complex I is very specific in respect to the RNA partner and its formation renders the RNA neither more nor less advantageous in forming phage-like particles with additional protein. [ABSTRACT FROM AUTHOR]

One of the peptide fragments obtained in a preceding study of the cyanogen bromide hydrolysate of S-sulfo-pepsin has been investigated in more detail. The peptide was purified by ion-exchange chromatography and obtained in homogeneous form. It contains 158 amino acid residues, among their number the only histidine residue of pepsin and two half-cystine residues. Evidence was obtained that the peptide is derived from the N-terminal region of the molecule of hog pepsin. The peptide was reduced by 2-mercaptoethanol and converted into its S-(β-amino- ethyl)-cysteinyl derivative. From the tryptic digest of this derivative a 105-residue peptide containing N-terminal isoleucine was isolated which represents the N-terminal segment of the pepsin molecule. [ABSTRACT FROM AUTHOR]

The size and shape of beef liver glutamate dehydrogenase were investigated by X-ray small- angle measurements in the range of protein concentration between 1 and 33 mg/mI. It was shown that the cross-section of the glutamate dehydrogenase particles of varying sizes were independent of the molecular weight of the particles. The radius of gyration of the cross-section (14) was found to be 30.3 Å and the mass per unit length (M/1Å) to be 2,340. From the comparison of the experimental scattering curves with theoretical cross-section curves for elliptical cylinders it follows that the glutamate dehydrogenase molecule has a very isotropic cross-section. The experimental data lie between the axial ratio 1: 1 (circular cross-section) and 0.8: 1. For the circular cross-section a diameter of 86 Å and a cross-section area of 5,800 Ų is calculated. For an axial ratio of 0.8: 1 the long and the short axes are calculated to be 95 Å and 76 Å, respectively, and the cross-section area is found to be 5,700 Ų. Again the cross-section is independent of protein concentrations and therefore independent of the state of association of glutamate dehydrogenase. This result confirms our earlier conclusion from diffusion, sedimentation and viscosity measurements, that the dissociation of the prolate glutamate dehydrogenase molecule into enzymatically active subunits involves a transverse cleavage. A linear relationship exists between the length and the molecular weight of the glutamate dehydrogenase particles. For a molecular weight of about two millions a length of 800- 900 Å was found, for molecular weights of one and one-half mill ions the length of the molecules were calculated to 400 Å and 200 Å, respectively. These data are confirmed by comparison of the experimental data with theoretical scattering curves of circular cylinders. The results support the conclusion that the associated enzyme molecule is formed in a stepwise association-dissociation equilibrium. The scattering curves of glutamate dehydrogenase show a pronounced side maximum at an angle corresponding to a Bragg's value of 56 Å. The comparison with theoretical cross-section curves of hollow cylinders suggests that glutamate dehydrogenase is loosely built and possesses voids. This suggestion is supported by the difference of the volume of glutamate dehydrogenase per 1 Å length calculated from the mass per 1 Å length (4,200 ų, even if one assumes an average swelling of proteS of 0.33 g H2O per 1 g protein) and from the cross-section area (5,700 to 5,800 ų). [ABSTRACT FROM AUTHOR]

Some optical and thermodynamic properties of the double helical form of the alternating copolymer poly(A-U) and the two stranded complex of poly A and poly U are compared. It is shown that their thermal difference spectra are closely similar when that of the latter complex is corrected for the hypochromicity of the poly A formed on denaturation. Similarly differences in their Tm and pHm values can be accounted for in terms of the free energy of stacking of the poly A formed on denaturation. It is suggested that sequence effects are of only marginal consequence in determining the optical and thermodynamic properties of two stranded helical poly-nucleotides. [ABSTRACT FROM AUTHOR]

A method of analysing melting profiles of stacked polynucleotides is described. This method assumes that the melting process is non-cooperative and that the optical parameter is proportional to the degree of stacking, but requires no assumption concerning the properties of the polymer in the fully stacked or fully unstacked conformation. It is equally applicable to absorption, optical rotation or circular dichroism data. The method has been applied to a high precision absorbance-temperature profile of alkaline polyadenylic acid and has enabled the calculation, subject to the assumptions noted above, of the absorption spectra of this material in both the fully stacked conformation and in the random coil conformation. It is suggested that not all the hypochromism of the polymer with respect to the monomer can be accounted for in terms of stacking. [ABSTRACT FROM AUTHOR]

The presence of carotenoids in Decapoda­Orconectes limosus (Raf.) was studied. In extracts from carapace Orconectes limosus1 separated by means of column and thin-layer chromatography, the following carotenoids were identified: β­carotene, echinenone, lutein (cpoxide and ester), astaxanthin (free and ester) and one unknown xanthophyll. [ABSTRACT FROM AUTHOR]

The dorsal skin of the hairless mouse when 'stripped' with sticky tape proved to be a suitable model for a study of the antimitotic effect of betamethasone-17-valerate and hydrocortisone. The application of 1%, betamethasone-17-valerate and 1% hydrocortisone creams under occlusive dressings for 24 h produced a three- to four-fold drop in the colcemid-induced mitotic index as compared to a control application. The antimitotic effect of the betamethasone-17-valerate preparation started at or before 5 h and continued for at least 4 days after removal of the active material. It was shown in addition, that 1%, betamethasone-17-valerate also reduced the number of cells entering DNA synthesis. The antimitotic effect of hydrocortisone was detected at a concentration of 10-2 and that of betamethasone-17-valerate was detected at a concentration of 10-4. It is suggested that the animal model used is a useful one for assaying the potency of topical corticosteroid compounds. [ABSTRACT FROM AUTHOR]

Discusses that sebum is one of the most complex biological lipids. Techniques in sebum analysis; Different methods of sampling surface lipids; Source of surface lipids.

Thus it seems from these preliminary experiments that dietary carbohydrates can alter the composition of skin surface fat in adult males and there may well be a scientific explanation for the clinical advice offered in the textbooks of the 1930's. [ABSTRACT FROM AUTHOR]

Skin surface lipids collected from the human back by swabbing with acetone contain 1-2 % of saturated hydrocarbons. This figure falls to 0.2 % in lipid collected under conditions contrived to eliminate contamination from clothing and from the environment. The saturated hydrocarbons normally found on the skin surface are considered to be contaminants derived from diverse petroleum products, rather than endogenous products of the skin. A possible contribution of these environmental hydrocarbons to the pathogenesis of comedones in acne vulgaris is- discussed. [ABSTRACT FROM AUTHOR]