Showing papers in "Nature in 1971"
TL;DR: Experiments with guinea-pig lung suggest that some of the therapeutic effects of sodium salicylate and aspirin-like drugs are due to inhibition of the synthesis of prostaglandins.
Abstract: Experiments with guinea-pig lung suggest that some of the therapeutic effects of sodium salicylate and aspirin-like drugs are due to inhibition of the synthesis of prostaglandins.
8,204 citations
TL;DR: The concept of crustal plate motion over mantle hotspots has been advanced to explain the origin of the Hawaiian and other island chains and the origin the Walvis, Iceland-Farroe and other aseismic ridges as discussed by the authors.
Abstract: THE concept of crustal plate motion over mantle hotspots has been advanced1 to explain the origin of the Hawaiian and other island chains and the origin of the Walvis, Iceland-Farroe and other aseismic ridges. More recently the pattern of the aseismic ridges has been used in formulating continental reconstructions2. I have shown3 that the Hawaiian-Emperor, Tuamotu-Line and Austral-Gilbert-Marshall island chains can be generated by the motion of a rigid Pacific plate rotating over three fixed hotspots. The motion deduced for the Pacific plate agrees with the palaeomagnetic studies of seamounts4. It has also been found that the relative plate motions deduced from fault strikes and spreading rates agree with the concept of rigid plates moving over fixed hotspots. Fig. 1 shows the absolute motion of the plates over the mantle, a synthesis which satisfies the relative motion data and quite accurately predicts the trends of the island chains and aseismic ridges away from hotspots.
2,277 citations
TL;DR: Recordings of the change in tension in striated muscle after a sudden alteration of the length have made it possible to suggest how the force between the thick and thin muscle filaments may be generated.
Abstract: Recordings of the change in tension in striated muscle after a sudden alteration of the length have made it possible to suggest how the force between the thick and thin muscle filaments may be generated.
2,050 citations
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TL;DR: Lipson and Steeple as mentioned in this paper interpreted X-ray powder diffraction patterns and found that powder-diffraction patterns can be represented by a set of 3-dimensional planes.
Abstract: Interpretation of X-ray Powder Diffraction Patterns . By H. Lipson and H. Steeple. Pp. viii + 335 + 3 plates. (Mac-millan: London; St Martins Press: New York, May 1970.) £4.
1,867 citations
TL;DR: It is shown that the purple colour is due to retinal bound to an opsin-like protein, the only protein present in this membrane fragment, which has been isolated in relatively pure form from Halobacterium halobium.
Abstract: HALOPHILIC bacteria require high concentrations of sodium chloride and lower concentrations of KCl and MgCl2 for growth. The cell membrane dissociates into fragments of varying size when the salt is removed1. One characteristic fragment—termed the “purple membrane” because of its characteristic deep purple colour—has been isolated in relatively pure form from Halobacterium halobium2. We can now show that the purple colour is due to retinal bound to an opsin-like protein, the only protein present in this membrane fragment (see also ref. 3).
1,849 citations
TL;DR: There are, however, frequent and often important errors in 14C bone measurements which arise chiefly because of the difficulty of eliminating completely the numerous pollutants during chemical treatment.
Abstract: DATING by the radiocarbon method is of primary importance for archaeological studies and on many sites bones are the only samples which can be dated1. The losses arising from the destruction of bones for dating purposes is not very important, whereas it is a pity to destroy clothes or wooden items associated with the civilization being studied. It is also more logical to use bones for dating an archaeological level than to use wood or artefacts, for example, which are not necessarily contemporary with the site occupation2. There are, however, frequent and often important errors in 14C bone measurements which arise chiefly because of the difficulty of eliminating completely the numerous pollutants during chemical treatment.
1,485 citations
TL;DR: Platelets in the blood of volunteers who have taken aspirin can no longer produce prostaglandins, and these platelets are removed from the body by the immune system.
Abstract: Platelets in the blood of volunteers who have taken aspirin can no longer produce prostaglandins.
1,472 citations
TL;DR: It seems probable, therefore, that the darker staining with Giemsa of these regions, after denaturation and annealing, indicates the presence of highly repetitive DNA.
Abstract: A GIEMSA staining procedure that preferentially stains centromeric heterochromatin in mouse chromosomes has been described1. This specificity was observed when fixed preparations were treated with sodium hydroxide to denature the DNA, and then incubated in warm saline to allow annealing, in the presence of 3H-labelled single stranded satellite DNA or its complementary RNA. In this way mouse satellite DNA was located in the centromeric heterochromatin1,2. It is known to consist of highly repetitive sequences3 and to anneal much more rapidly than non-repetitive DNA4. It seems probable, therefore, that the darker staining with Giemsa of these regions, after denaturation and annealing, indicates the presence of highly repetitive DNA.
1,140 citations
TL;DR: A possible mechanism for lymphocyte triggering by antigen is suggested and questions about cell membrane structure are raised.
Abstract: Antibody reacting with lymphocyte surface immunoglobulin molecules induces these to gather over one pole of the cell. This suggests a possible mechanism for lymphocyte triggering by antigen and raises questions about cell membrane structure.
1,106 citations
TL;DR: The action of these two anti-inflammatory agents provides further support for the suggestion that some of their therapeutic effects depend on the inhibition of the production of prostaglandin.
Abstract: The action of these two anti-inflammatory agents provides further support for the suggestion that some of their therapeutic effects depend on the inhibition of the production of prostaglandin.
894 citations
TL;DR: Synchrony and suppression among a group of women living together in a college dormitory suggest that social interaction can have a strong effect on the menstrual cycle as discussed by the authors, which is similar to our experience.
Abstract: Synchrony and suppression among a group of women living together in a college dormitory suggest that social interaction can have a strong effect on the menstrual cycle.
TL;DR: The initial studies were made on crude acid alcohol extracts of equine brain and intestine, dried in powder form, and the active principle in the preparation was later referred to as substance P (P for powder), and this non-committal term subsequently achieved widespread acceptance in the literature, in the absence of any clearly definable biological role.
Abstract: IN 1931 von Euler and Gaddum1, studying the tissue distribution of acetylcholine, found that brain and intestine contained a substance that stimulated contraction of the isolated rabbit jejunum, and caused transient hypotension when injected intravenously into anaesthetized rabbits. These effects could not be ascribed to acetylcholine, for they were not prevented by the previous administration of atropine. The initial studies were made on crude acid alcohol extracts of equine brain and intestine, dried in powder form. The active principle in the preparation was later referred to as substance P (P for powder), and this non-committal term subsequently achieved widespread acceptance in the literature, in the absence of any clearly definable biological role for the compound (or compounds) involved.
TL;DR: Injected frog eggs and oocytes provide a very sensitive assay system for the identification of messenger RNA and permit the study of translational control in living cells.
Abstract: Injected frog eggs and oocytes provide a very sensitive assay system for the identification of messenger RNA and permit the study of translational control in living cells. The translation of each haemoglobin messenger RNA molecule once every 5–10 minutes for at least 24 hours makes it possible to recognize less than 1 ng of this messenger RNA.
TL;DR: In this article, the authors have learned that this result was shown earlier by Marczewski and Steinhaus and regret the consequent redundancy of their paper, and they tried to ensure its novelty by searching standard references and enquiring among mathematicians and statisticians.
Abstract: SINCE the publication of our communication on the metric properties of the one-complement of Jaccard's similarity coefficient1, we have learned that this result was shown earlier by Marczewski and Steinhaus2. We regret the consequent redundancy of our paper. We tried to ensure its novelty by searching standard references and enquiring among mathematicians and statisticians, but apparently the earlier work, more extensive than ours, is not well known. We hope publication of our paper will have the positive effect of making it more well known. It is interesting that the earlier work also occurred in an ecological context3. A discussion of these and other properties of this useful function occurs in a recent contribution by Holgate4, who refers to it as the Marczewski–Steinhaus coefficient of similarity.
TL;DR: A simple method for estimating the secondary structure of an RNA molecule has been proposed on the basis of the knowledge of its sequence.
Abstract: A simple method for estimating the secondary structure of an RNA molecule has been proposed on the basis of the knowledge of its sequence.
TL;DR: Corneal epithelium, nonetheless, has considerable healing capacity, which is achieved primarily by migration of epithelial cells, and should correspond to higher demands on the generative capacity of the corneal basal cells compared with skin.
Abstract: THE human cornea is covered by a five-layered epithelium. Cells are continually shed from its surface and replaced by division of the basal cells, which has a mean generation time estimated to be about 4 days1. Because of the papillae in the skin, the relation between the area of the basal cell layer and the surface is about 20 : 1. Because it must be refractive, there can be no papillae on the cornea, and the relation between the basal cell layer and the surface is accordingly 1 : 1. This should correspond to higher demands on the generative capacity of the corneal basal cells compared with skin. The epidermal basal cells are in close contact with a well developed capillary network. There are no vessels in the cornea, and so it can be assumed that the supply of its epithelium is poorer. Corneal epithelium, nonetheless, has considerable healing capacity, which is achieved primarily by migration of epithelial cells.
TL;DR: The speed/velocity distribution functions have been measured for three crowd fluids in the gaseous phase and good agreement is obtained with Maxwell-Boltzmann theory except for a significant deviation near the frequency mode of each distribution.
Abstract: The speed/velocity distribution functions have been measured for three crowd fluids in the gaseous phase. Good agreement is obtained with Maxwell-Boltzmann theory except for a significant deviation near the frequency mode of each distribution. This is attributed to sexual inhomogeneity.
TL;DR: Contrary to the conclusions of Piaget, young children can make transitive inferences if precautions are taken to prevent deficits of memory from being confused with inferential deficits.
Abstract: Contrary to the conclusions of Piaget, young children can make transitive inferences if precautions are taken to prevent deficits of memory from being confused with inferential deficits.
TL;DR: In this article, the fluorescence emission of complex mixtures of fluorescent compounds sometimes cannot be satisfactorily resolved by the usual technique of excitation at various fixed wavelengths selected specifically for individual components.
Abstract: THE fluorescence emission of complex mixtures of fluorescent compounds sometimes cannot be satisfactorily resolved by the usual technique of excitation at various fixed wavelengths selected specifically for individual components. Considerable improvement in such spectra often can be made when excitation and emission wavelengths are varied together, so that the fluorescence contributed by each component is restricted to that excited at wavelengths synchronously trailing the plotted emission.
TL;DR: This work has made use of the observation that free ribosomes from hamster cells form dimers in conditions where mouse free Ribosomes remain as monomers, dimers or as both to determine whether mouse-hamster hybrid cells contain freeribosomes as monomer, dimer or both.
Abstract: ONLY mouse 28S ribosomal RNA (rRNA) can be detected in mouse-human hybrid cells1. Because these cells contain as many as thirty-five human chromosomes, including those believed to have ribosomal RNA genes, it has been suggested that the transcription of human ribosomal RNA genes may be repressed. Similar studies have not been performed with mouse-hamster hybrid cells because hamster and mouse 28S rRNAs have only a very small difference in their electro-phoretic mobilities2. We have now made use of the observation that free ribosomes (not engaged in translation) from hamster cells form dimers in conditions where mouse free ribosomes remain as monomers3 to determine whether mouse-hamster hybrid cells contain free ribosomes as monomers, dimers or as both.
TL;DR: Three protein preparations from the rat liver 100,000g supernatant fraction have been independently purified to homogeneity, and they are basic azodye carcinogen-binding protein (β-ABP), corticosteroid Binder I3,4 and Y protein5.
Abstract: THREE protein preparations from the rat liver 100,000g supernatant fraction have been independently purified to homogeneity. They are basic azodye carcinogen-binding protein (β-ABP)1,2, corticosteroid Binder I3,4 and Y protein5. The compounds they bind include certain steroids and their metabolites, bilirubin and certain carcinogens and their metabolites. Several dyes and cholecystographic agents and other organic anions are also bound (Table 1). Binding occurs whether the compounds are injected in vivo or added in vitro to liver homogenates.
TL;DR: The cytotoxicities of double stranded RNA and endotoxin have striking similarities and both seem to render mouse macrophages cytotoxicity to other mouse cells.
Abstract: The cytotoxicities of double stranded RNA and endotoxin have striking similarities. Both seem to render mouse macrophages cytotoxic to other mouse cells.
TL;DR: Myosin from fast skeletal muscles consists of two large subunits and approximately four smaller subunits which are heterogeneous in both size and charge, irrespective of the muscle type of origin.
Abstract: Myosin from fast skeletal muscles consists of two large subunits (each about 200,000 daltons) and approximately four smaller subunits (in the range of 20,000 daltons). The light chains are heterogeneous in both size and charge, irrespective of the muscle type of origin. Moreover, the myosins from fast muscles of several species show a characteristic light chain pattern which is distinct from that of slower muscles.
TL;DR: A vitamin D metabolite, 25-dihydroxycholecalciferol, is further hydroxylated by kidney before acting as a hormone on target tissues and the structure is described.
Abstract: A vitamin D metabolite, 25-dihydroxycholecalciferol, is further hydroxylated by kidney before acting as a hormone on target tissues. The structure of this kidney metabolite is now described.
TL;DR: It is proposed that random genetic drift of neutral mutations in finite populations can account for observed protein polymorphisms.
Abstract: It is proposed that random genetic drift of neutral mutations in finite populations can account for observed protein polymorphisms.
TL;DR: The fact that rats treated with pitressin retain the avoidance response for a considerable time after treatment suggests that this preparation contains peptides which interfere with long term memory storage, but that peptides with a configuration like that of ACTH participate in short term memory processes3.
Abstract: RATS subjected to posterior lobectomy are unable to maintain a shuttle-box avoidance response without reinforcement1, but normal behaviour can be restored to that of sham-operated controls by treatment with pitressin tannate in oil, a relatively crude extract of posterior and intermediate pituitary lobes. Long acting preparations of ACTH and α-MSH can also restore the normal rate of extinction of an avoidance response in posterior lobectomized rats2. Pitressin as well as ACTH analogues, including α-MSH, delay the extinction of an avoidance response also in intact rats3,4. Treatment with pitressin tannate in oil, however, preserves a conditioned avoidance response whether the treatment is given during acquisition or extinction, while ACTH or ACTH analogues inhibit extinction most markedly during the treatment period3. These observations suggest that the mechanisms by which pitressin and analogues of ACTH affect conditioned avoidance behaviour are basically different. The fact that rats treated with pitressin retain the avoidance response for a considerable time after treatment suggests that this preparation contains peptides which interfere with long term memory storage, but that peptides with a configuration like that of ACTH participate in short term (trial to trial) memory processes3.
TL;DR: In this article, the authors consider the extraction of rotational energy from a black hole, not least because the rotational energies should be comparable with the total mass energy of the black hole.
Abstract: THERE has been considerable interest recently in the question of the gravitational collapse of a massive body and of the possible astrophysical consequences of the existence of the “black hole” which general relativity predicts should sometimes be the result of such a collapse. In particular, the question has arisen whether the mass-energy content of a black hole could, under suitable circumstances, be a source of available energy. We now consider the extraction of rotational energy from a black hole, not least because the rotational energy (defined appropriately) of a black hole should, in general, be comparable with its total mass-energy1.
TL;DR: A technique for obtaining a high proportion of viable embryos after subjecting them to sub-zero temperatures is described.
Abstract: COMPARED with the successful storage of spermatozoa and other tissue cells at sub-zero temperatures, attempts to preserve frozen mammalian eggs have been disappointing (reviewed in refs. 1 and 2), although a few pregnancies have resulted from the transfer of previously frozen fertilized rabbit eggs3 and unfertilized mouse eggs4 to recipient foster mothers. I now wish to describe a technique for obtaining a high proportion of viable embryos after subjecting them to sub-zero temperatures.
TL;DR: The structure of the purple membrane and its localization in the bacterial cell envelope are described and it is shown that it contains retinal bound in a mole ratio of 1 : 1 to a protein of molecular weight 26,000 which is the only protein present.
Abstract: IN the preceding article1 it has been shown that a cell membrane fragment, the purple membrane, isolated from Halobacterium halobium2 contains retinal bound in a mole ratio of 1 : 1 to a protein of molecular weight 26,000 which is the only protein present. We now describe the structure of the purple membrane and its localization in the bacterial cell envelope.
TL;DR: Physico-chemical experiments show that histones are not evenly distributed in chromatin, and about half of the DNA is “open” and not covered with proteins.
Abstract: Physico-chemical experiments show that histones are not evenly distributed in chromatin. About half of the DNA is “open” and not covered with proteins.