Showing papers in "Nature in 1975"
TL;DR: The derivation of a number of tissue culture cell lines which secrete anti-sheep red blood cell (SRBC) antibodies is described here, made by fusion of a mouse myeloma and mouse spleen cells from an immunised donor.
Abstract: THE manufacture of predefined specific antibodies by means of permanent tissue culture cell lines is of general interest. There are at present a considerable number of permanent cultures of myeloma cells1,2 and screening procedures have been used to reveal antibody activity in some of them. This, however, is not a satisfactory source of monoclonal antibodies of predefined specificity. We describe here the derivation of a number of tissue culture cell lines which secrete anti-sheep red blood cell (SRBC) antibodies. The cell lines are made by fusion of a mouse myeloma and mouse spleen cells from an immunised donor. To understand the expression and interactions of the Ig chains from the parental lines, fusion experiments between two known mouse myeloma lines were carried out.
19,053 citations
TL;DR: The evidence is based on the determination of the amino acid sequence of natural enkephalin by the dansyl–Edman procedure and by mass spectrometry followed by synthesis and comparison of the natural and synthetic peptides.
Abstract: Enkephalin, a natural ligand for opiate receptors is composed of the pentapepides H-Tyr-Gly-Gly-Phe-Met-OH and H-Tyr-Gly-Gly-Phe-Leu-OH. The evidence is based on the determination of the amino acid sequence of natural enkephalin by the dansyl-Edman procedure and by mass spectrometry followed by synthesis and comparison of the natural and synthetic peptides.
3,580 citations
TL;DR: A 7-Å resolution map of the purple membrane has been obtained by electron microscopy of tilted, unstained specimens and shows that Lipid bilayer regions fill the spaces between the protein molecules.
Abstract: A 7-A resolution map of the purple membrane has been obtained by electron microscopy of tilted, unstained specimens. The protein in the membrane contains seven, closely packed, alpha-helical segments which extend roughly perpendicular to the plane of the membrane for most of its width. Lipid bilayer regions fill the spaces between the protein molecules.
2,114 citations
TL;DR: A highly flexible method based on affinities which can be used in a more selective fashion by modern chromatographic techniques is described here.
Abstract: CONVENTIONAL nonspecific precipitation methods sometimes depend on affinities which can be used in a more selective fashion by modern chromatographic techniques. The affinity of proteins for heavy metal ions, for example, may provide a basis for their purification and analysis. A highly flexible method based on such affinities is described here.
2,063 citations
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TL;DR: The Economy of Nature and the Evolution of Sex*.
Abstract: The Economy of Nature and the Evolution of Sex *. By Michael T. Ghiselin. Pp. xii + 346. (University of California: Berkeley, Los Angeles and London, December 1974.) $12.05; £7.10.
2,034 citations
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TL;DR: Understanding Homosexuality : Its Biological and Psychological Bases by J. A. Loraine.
Abstract: Understanding Homosexuality : Its Biological and Psychological Bases. By J. A. Loraine. Pp. 217. (Medical and Technical Publishing: Lancaster, October 1974.) £6.50.
1,706 citations
TL;DR: Complementarity relationships between this sequence and a purine-rich tract in the ribosome binding site of different bacterial mRNAs suggest that the 3′-end of 16S RNA determines the intrinsic capacity of ribosomes to translate a particular cistron.
Abstract: The sequence of the 3'-terminus of 16S RNA from different bacteria has been determined. Complementarity relationships between this sequence and a purine-rich tract in the ribosome binding site of different bacterial mRNAs suggest that the 3'-end of 16S RNA determines the intrinsic capacity of ribosomes to translate a particular cistron.
1,323 citations
TL;DR: A staining technique that detects sister chromatid exchanges (SCEs) has been used to examine the response of chromosomes in cultured Chinese hamster cells to a wide variety of mutagens–carcinogens.
Abstract: A staining technique that detects sister chromatid exchanges (SCEs) has been used to examine the response of chromosomes in cultured Chinese hamster cells to a wide variety of mutagens-carcinogens. The test gives a very sensitive and rapid method for detecting chromosome mutagenicity of chemical agents and provides a powerful new method for detecting environmental mutagens.
1,306 citations
TL;DR: The ability of the infant to respond successfully to such signals allows the mother to isolate and highlight a much wider range of environmental features than if the infant ignores her attention-directing efforts.
Abstract: LITTLE is known about how visual attention of the mother–infant pair is directed jointly to objects and events in the visual surround during the first year of the child's life. To what extent does the child follow the mother's lead and the mother the child's, and what are the processes involved? The ability of the infant to respond successfully to such signals allows the mother to isolate and highlight a much wider range of environmental features than if the infant ignores her attention-directing efforts. We report a preliminary investigation of the extent of the infant's ability to follow changes in adult gaze direction during the first year of life.
1,017 citations
TL;DR: Results indicate that hydrophobicity is the major factor stabilising protein–protein association, while complementarity plays a selective role in deciding which proteins may associate.
Abstract: The formation of the protein–protein interface by the insulin dimer, the trypsin-PTI complex and the αβ oxyhaemoghbin dimer removes 1,130–1,720 A2 of accessible surface from contact with water. The residues forming the interface are close packed: each occupies the same volume as it does in crystals of amino acids. These results indicate that hydrophobicity is the major factor stabilising protein–protein association, while complementarity plays a selective role in deciding which proteins may associate.
1,003 citations
TL;DR: Fast-twitch muscles contain myosin showing heterogeneity of both light and heavy chains, suggesting isoenzyme populations, but so far these have not been separated, nor have the proteolytic subfragments derived from them.
Abstract: RABBIT skeletal muscle myosin is composed of two heavy chains and four light chains1. Two classes of light chains can be distinguished both chemically and functionally. Within the class of essential light chains (those which cannot be removed without loss of ATPase activity), two chemically related but pheno-typically distinct proteins have been identified2, both of which are present in single fibres of fast-twitch muscles3. The existence of both phenotypes within a single psoas muscle cell indicates that either there is a single population of myosin molecules with a different alkali light chain on each subfragment-1 head, or there are at least two populations of myosin present. Densitometric and radiochemical methods have shown that there is an unequal distribution of these two light chains; this supports the hypothesis that myosin isoenzymes occur in histochemically homogeneous muscles3–5 which cannot be attributed to the presence of contaminating slow-twitch fibres. The presence of different heavy chains also is indicated by the observation of amino acid substitutions in certain peptide sequences6,7. Thus fast-twitch muscles contain myosin showing heterogeneity of both light and heavy chains, suggesting isoenzyme populations, but so far these have not been separated, nor have the proteolytic subfragments derived from them.
TL;DR: Cell survival experiments are reported which indicate that the clinically observed enhanced sensitivity of AT patients to ionising radiation is manifest at the cellular level.
Abstract: ATAXIA telangiectasia (AT) is an autosomal recessive defect in man showing among the clinical features1 : cerebellar ataxia, telangiectasia, IgA deficiency, an enhanced frequency of malignancy and an enhanced level of spontaneous chromosome instability2 There have also been reports of increased sensitivity to X rays after radiotherapy3–5 and increased chromosome aberrations induced by ionising radiation in leukocyte cultures from AT patients6,7 We report here cell survival experiments which indicate that the clinically observed enhanced sensitivity of AT patients to ionising radiation is manifest at the cellular level
TL;DR: A new and very simple representation of protein conformations has been used together with energy minimisation and thermalisation to simulate protein folding and succeeds in ‘renaturing’ bovine pancreatic trypsin inhibitor from an open-chain conformation into a folded conformation close to that of the native molecule.
Abstract: A new and very simple representation of protein conformations has been used together with energy minimisation and thermalisation to simulate protein folding Under certain conditions, the method succeeds in ‘renaturing’ bovine pancreatic trypsin inhibitor from an open-chain conformation into a folded conformation close to that of the native molecule
TL;DR: The first stages in development of a noninvasive method for acquiring information which has a rapid response and the potential ability to distinguish flow in the different microvascular compartments by the differences in flow velocities are reported.
Abstract: THE microcirculation plays a central role in the regulation of the metabolic, haemodynamic and thermal state of the individual. Its physiological state varies over both long and short time periods and reflects the state of health of the individual; in particular it is the ultimatearbiter of the adequacy of tissue perfusion in the presence of vascular disease or injury. For these reasons it is of interest to both the physiologist and the clinician to be able to monitor the state of flow and distribution of flow in the compartments of the microvasculature rapidly, conveniently and with minimal interference with the many local and central reflex controls. At present such measurements depend on direct observation, plethysmography thermal or radioisotope techniques1, which are slow or cumbersome or grossly disturb the normal state of the subject. We report here the first stages in development of a noninvasive method for acquiring such information which has a rapid response and the potential ability to distinguish flow in the different microvascular compartments by the differences in flow velocities.
TL;DR: Three possible protective mechanisms are discussed and it is shown how they could explain various features of the natural history of certain common cancers of man.
Abstract: Survival of the rapidly renewing tissues of long-lived animals like man requires that they be protected against the natural selection of fitter variant cells (that is the spontaneous appearance of cancer). This article discusses three possible protective mechanisms and shows how they could explain various features of the natural history of certain common cancers of man.
TL;DR: A temperature-sensitive mutant strain of the fission yeast Schizosaccharomyces pombe has been isolated which divides at half the size of the wild type, suggesting that there is a cell size control over DNA synthesis and a second control acting on nuclear division.
Abstract: A temperature-sensitive mutant strain of the fission yeast Schizosaccharomyces pombe has been isolated which divides at half the size of the wild type. Study of this strain suggests that there is a cell size control over DNA synthesis and a second control acting on nuclear division.
TL;DR: An analysis of 15 protein structures indicates: first, the loss of accessible surface area by monomeric proteins on folding—proportional to hydrophobic energy—is a simple function of molecular weight.
Abstract: An analysis of 15 protein structures indicates: First, the loss of accessible surface area by monomeric proteins on folding-proportional to hydrophobic energy-is a simple function of molecular weight; second, the proportion of polar groups forming intramolecular hydrogen bonds is constant; and third, protein interiors are closely packed, each residue occupying the same volume as it does in crystals of amino acids.
TL;DR: The permeability of the amphibian oocyte nuclear envelope in situ has been determined for three tritiated dextrans and the envelope is a sieve restricting molecular movement between the cytoplasm and nucleus.
Abstract: The permeability of the amphibian oocyte nuclear envelope in situ has been determined for three tritiated dextrans. The envelope is a sieve, restricting molecular movement between the cytoplasm and nucleus. The patent radius of its pores is about 45 A.
TL;DR: In an effort to determine the embryonic stage at which the X chromosome initiates differentiation in famale mouse embryos heterozygous for Cattanach's translocaton, it was found that the mosaic composition was consistently biased in extraembryonic membranes, whereas it was not necessarily so in the embryonic body.
Abstract: RANDOM X inactivation makes the female mammal a natural mosaic for clones of cells having either the maternally derived X (Xm) or paternally derived one (Xp) which is genetically inactive1. There are, however, instances in which inactivation is obviously not random2–7. Non-randomness was inferred from studies made on differentiated cells remote from early embryonic cells in which inactivation occurred. Thus it is not clear whether the randomness of the X inactivation process was influenced or whether cell selection occurring after random inactivation was responsible for the ultimate non-random appearance4–9. In an effort to determine the embryonic stage at which the X chromosome initiates differentiation in famale mouse embryos heterozygous for Cattanach's translocaton10, we found that the mosaic composition was consistently biased in extraembryonic membranes, whereas it was not necessarily so in the embryonic body.
TL;DR: DAPI will bind differentially to yeast mitochondrial and nuclear DNA forming highly fluorescent complexes and enhancing the separation of the two DNAs in caesium chloride gradients, which can be used as a highly specific fluorescent stain for both nuclear and mitochondrial DNA in yeast.
Abstract: 4′-6-DIAMIDINO-2-PHENYLINDOLE (DAPI), which was first synthesised by Dann et al.1 as a trypanocide related to Berenil, has been shown to possess useful DNA binding properties2. Thus, DAPI will bind differentially to yeast mitochondrial and nuclear DNA forming highly fluorescent complexes and enhancing the separation of the two DNAs in caesium chloride gradients2. DAPI can also be used as a highly specific fluorescent stain for both nuclear and mitochondrial DNA in yeast. It seems to be highly sensitive and probably permits detection of a single yeast mitochondrial DNA molecule (D.H.W., and D. J. Fennell, unpublished).
TL;DR: To establish the true nature of these agents, and in particular their possible role in the therapeutic control of peptic ulceration it was necessary to make a full chemical identification.
Abstract: THE clinical observation of the very low incidence of peptic ulceration during pregnancy led to the finding that extracts of the urine of pregnant women had a beneficial effect on experimental ulcers in dogs1. It was later reported that not only pregnancy urine but also that from all females and males contained a potent inhibitor of gastric acid secretion2,3. Sandweiss4 named the anti-ulcer factor anthelone and regarded it as having a therapeutic effect on ulcers without depressing gastric acid secretion. The antisecretory agent was thought to be a separate entity and was called urogastrone because its actions resembled those of the postulated duodenal hormone enterogastrone5. Subsequent work amply demonstrated urogastrone action, but the existence of anthelone as a separate entity remained less well established. To establish the true nature of these agents, however, and in particular their possible role in the therapeutic control of peptic ulceration it was necessary to make a full chemical identification. Many attempts have been made to isolate urogastrone, and probably the most highly purified sample on record was that obtained by Gregory6. This was described as a combination of a golden yellow fluorescent pigment and a protein of relatively low molecular weight. Others have provided additional evidence of a protein structure7 but some recent work has led to the suggestion that urogastrone is a high-molecular weight glycoprotein8,9. Nevertheless its exact nature, source10 and physiological role have remained unknown. Gastric inhibitory effects have also been shown by extracts of animal urine but studies were undertaken on the nature of urogastrone from more readily available human urine.
TL;DR: Evidence for the presence in the vertebrate nervous system of a hitherto undescribed brain gastrin immunoassayable peptide (BGP) is presented here.
Abstract: RELEASING factors1 and other brain peptides2 have been the subject of extensive studies and the high sensitivity of modern measurement techniques has led to the discovery, in various tissues3,4 and in the nervous system5–9, of new, unpredicted locations for otherwise well known peptides. Evidence for the presence in the vertebrate nervous system of a hitherto undescribed brain gastrin immunoassayable peptide (BGP) is presented here.
TL;DR: This work proposes a possible selective mechanism, based on the realisation that immunological surveillance function (defined here as recognition and elimination of modified host cells by sensitised thymus-derived lymphocytes (T-cells) may be considerably enhanced in mice heterozygous at the H-2 gene complex), which may benefit heterozygotes in the HL-A system for man.
Abstract: THE major histocompatibility (H) antigens of higher animals show extreme genetic polymorphism equalled, in higher vertebrates, only by that associated with the immunoglobulins1. Maintenance of such a high rate of variability implies evolutionary advantage for heterozygotes in the HL-A system for man, or at the H-2 gene complex in mice2,3. We propose a possible selective mechanism, based on the realisation that immunological surveillance function (defined here as recognition and elimination of modified host cells by sensitised thymus-derived lymphocytes (T-cells) may be considerably enhanced in mice heterozygous at the H-2 gene complex.
TL;DR: In this paper, the authors suggest that the pulsars can be explained by the noisiness in the rate of creep of vorticity through the neutron superfluid in the crust, in almost precise analogy to the well known noisy behaviour of flux creep in hard superconducting magnets.
Abstract: SEVERAL pulsars1 have “restless” behaviour of the period similar to that of the Crab and Vela pulsars2 which has been explained3 as due to “microquakes” in the crust. A glitch has also been observed1 with, possibly, a new type of signature, in PSR1508+55. We suggest that these phenomena can be explained at least equally well by noisiness in the rate of creep of vorticity through the neutron superfluid in the crust, in almost precise analogy to the well known noisy behaviour of flux creep in hard superconducting magnets4. In addition, even the macroglitches, especially those in the Vela pulsar, may be caused by the catastrophic release of pinned vorticity.
TL;DR: Each subunit of triose phosphate isomerase is composed of alternate segments of polypeptide chain in the α- and β-conformations that are arranged to form an inner cylinder of parallel-pleated sheet and a largely helical outer shell.
Abstract: Structure of chicken muscle triose phosphate isomerase determined crystallographically at 2.5A resolution: using amino acid sequence data
TL;DR: In this paper, it was shown that the tidal breakup of stars passing within the Roche limit of a black hole initiates a chain of events that may explain many of the observed principal characteristics of QSOs and the nuclei of Seyfert galaxies.
Abstract: The possible presence of massive black holes in the nuclei of galaxies has been suggested many times. In addition, there is considerable observational evidence for high stellar densities in these nuclei. I show that the tidal breakup of stars passing within the Roche limit of a black hole initiates a chain of events that may explain many of the observed principal characteristics of QSOs and the nuclei of Seyfert galaxies.
TL;DR: The effect of electroconvulsive treatment, as it is generally accepted to be one of the most effective treatments for severe depression, is tested, on the reactivity of the cyclic AMP-generating system to NA.
Abstract: STUDIES on the pharmacology of the noradrenergic cyclic AMP-generating system in slices from the limbic forebrain of the rat1 and on adaptive properties of this system in conditions of persistent changes in the availability of nor-adrenaline (NA) have revealed that the system may serve as a model for the central NA receptor in this area, and that its sensitivity to NA increases or decreases when the availability of NA at the receptor site decreases or increases respectively2,3. Thus, hypersensitivity of the system has been achieved by treatment with reserpine2, a drug known to precipitate occasionally severe depressive reactions in man4, and the syndrome of which, when elicited in animals, is widely used as a model for depression5–7. Conversely, the monoamine oxidase (MAO) inhibitors, pargyline and nialamide, caused a marked reduction in the reactivity of the cyclic AMP-generating system to NA after chronic administration3. To determine whether or not antidepressant drugs which do not elevate the level of monoamines in brain share the effect of MAO inhibitors on the noradrenergic cyclic AMP-generating system, we studied the effect of the tricyclic antidepressants, desipramine and iprindole, on the reactivity of the system to NA. Desipramine blocks the uptake of NA through the neuronal membrane8,9 whereas iprindole neither blocks the neuronal uptake of NA nor alters its metabolism or turnover10,11, but is nevertheless a potent antidepressant12–14. In addition, we have tested the effect of electroconvulsive treatment (ECT), as it is generally accepted to be one of the most effective treatments for severe depression15.
TL;DR: The pattern of digits obtained is consistent with a model based on diffusion of a labile morphogen and is thus similar to models proposed for the development of pattern in invertebrates.
Abstract: The interpretation of positional information can provide the basis for pattern formation in limb morphogenesis. The gradient in positional information along the antero-posterior axis, which is specified with respect to a localised boundary region, can be modified by grafting this region to successive positions along the axis. The pattern of digits obtained is consistent with a model based on diffusion of a labile morphogen and is thus similar to models proposed for the development of pattern in invertebrates.
TL;DR: In this article, it was shown that loudness fluctuations in music and speech and pitch (melody) fluctuation in music exhibit 1/f-like power spectra over many decades of frequency.
Abstract: THE power spectrum S(f), of many fluctuating physical variables, V(t), is ‘1/f-like’, varying as f−γ (0.5≲γ≲1.5), over many decades of frequency (see ref. 1 for review). We have found that loudness fluctuations in music and speech, and pitch (melody) fluctuations in music exhibit 1/f power spectra.
TL;DR: The three-dimensional structure of a chlorophyll-containing protein has been determined by X-ray crystallography and shown to consist of three identical subunits, each containing a core of seven bacteriochlorophylls arranged in an irregular fashion and enclosed within an envelope of protein.
Abstract: The three-dimensional structure of a chlorophyll-containing protein has been determined by X-ray crystallography and shown to consist of three identical subunits, each containing a core of seven bacteriochlorophylls arranged in an irregular fashion and enclosed within an envelope of protein.