In vitro inactivation of the neurotoxic action of β-bungarotoxin by the marine natural product,manoalide

Summary The irreversible neurotoxic action of -bungarotoxin (-BuTx) can be prevented by preincubation of the toxin with manoalide, a non-steroidal anti-inflammatory agent. Manoalide was also found to inactivate purified phospholipase A₂ and thus prevent hydrolysis of phosphatidylcholine. PLA₂ is a component found in several neurotoxic venoms and is also a rate limiting enzyme important in phospholipid metabolism and prostaglandin synthesis in man.This work is a result of research sponsored in part by NOAA-Department of Commerce under Sea Grant No. NA80AA-D-00120 and the California State Resources Agency R/MP-21. The US Government is authorized to produce and distribute reprints for governmental purposes. A preliminary report of aspects of this work appeared in Fedn Proc.42 (1983) 374. We also acknowledge the technical assistance of Dan Rohrer. Dr George Taborski's advice and assistance during the course of this work is gratefully acknowledged.J. C. de Freitas is a post-doctoral fellow supported by Fundacao de Amparo à Pesquisa do Estado de São Paulo (81/0263-9) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (201.171/82), Brazil.     

Corticotropin releasing factor increases the adrenocortical responsiveness to adrenocorticotropin

Summary In the course of studying the plasma adrenocorticotropic hormone (ACTH) and corticosterone responses to synthetic corticotropin releasing factor (CRF), we noted some disparity in the responses. A higher dose (20 g compared with 5 g per rat i.a.) produced an equal plasma ACTH but greater plasma corticosterone response in adult male rats. Thus, we examined the possibility that CRF increases adrenocortical responsiveness to ACTH. CRF significantly (p<0.0005) increased the plasma corticosterone response to ACTH in rats pretreated with dexamethasone. Thus, synthetic CRF increases corticosterone secretion in rats not only by stimulating ACTH secretion, but also by increasing the adrenocortical responsiveness to ACTH.Acknowledgments. This research was supported by grant MT-5183 from the Medical Research Council of Canada and by the Department of Medicine, University of Kentucky.     

Increased competence as a process of surviving in shared information spaces

Connections between people and groups are growing more frequent and more intense. Cultural events, changes in laws, activities of organizations, and new ideas elsewhere affect one's own decisions and activities more and more. This development has strong implications for the way people can increase their competence and how they can affect what happens to their own community or geographical area. In this paper consequences are considered for a special type of tool, the so-called problem language, that appears to be intimately entwined with many other tools in operations research, cybernetics, and systems research. The language appears most adequate in situations where boundaries can be found such that external events have minimal impact on what happens inside those boundaries. The change in connectivity makes finding such boundaries less and less probable. This suggests looking for another language, to structure the processes necessary when one intends to overcome difficulties that cannot be represented and solved as problems. A language of access is proposed, derived partly from studies in areas where it has never been possible to find boundaries as indicated. Within the framework of this language one can derive methods of externalization that imply speeding up flows of information in a shared workspace or shared information space. Their implementation is greatly facilitated—or even made possible at all—by recent developments in information technology.     

(Na/ + K+)ATPase has one functioning phosphorylation site per alpha subunit

(Na+ + K+)ATPase contains two different subunits, a catalytic subunit (alpha) and a subunit with uncertain function (beta). The enzyme binds ATP, ouabain and vanadate, and can be phosphorylated by ATP as well as by inorganic phosphate. From the previously reported maximal binding and phosphorylation capacities of 3.5--4.3 nmol P per mg protein (based on Lowry protein determination) and the earlier molecular weight value of approximately 250,000, a molar binding and phosphorylation capacity of 0.87--1.07 mol per mol enzyme was derived. As it is generally agreed that the enzyme molecule contains two alpha subunits or even a multiple of two, it has been suggested that the enzyme operates by means of a so-called "half-of-the-sites mechanism" whereby only of the two alpha subunits can be phosphorylated at any one time. We now present evidence that every alpha subunit can be phosphorylated simultaneously, which rules out the operation of such a mechanism.     

Effect of acetylsalicylate on surgical bleeding, postoperative mortality and allograft survival in rats undergoing heart transplantation.

18 rats were treated with L-ASA before heart transplantation and daily thereafter until death or rejection. 22 animals acted as controls. A significantly higher post-operative mortality rate, without any significant modification of the transplant survival time, was found in L-ASA-treated group.     

Ultrastructural localization of vanadium in the blood cells of Ascidiacea

Summary X-ray histospectrographic analysis at the scanning and transmission electron microscope (STEM) are made on the blood cells ofPhallusia mamillata Cuvier andCiona intestinalis, to study the direct intracellular sites of accumulation of vanadium. The results show a clear accumulation of vanadium on the membrane and in the granules of vacuoles of amebocytes, signet ring cell, compartment cell and traces of metal in the vanadophores of vanadocytes.We thank Dr C. Weichan and Mr G. Hubert for kind hospitality and for technical assistance in the Department of Electron Microscopy of Siemens Laboratory in Karlsruhe (BRD). We thank also Dr V. Andria of Siemens Elettra in Rome (Italy).     

Narciclasine,an inhibitor of protein synthesis. Action onAllium cepa L. root meristems

Summary Shortening of nucleologenesis time in a synchronous cell population, labelled as binucleate, by a caffeine pulse and fall in frequency of prophases are related to narciclasine inhibition of protein synthesis inAllium cepa L. meristems.Acknowledgments. We gratefully acknowledge Dr D. Vázquez and Dr A. Jiménez, from the Instituto de Bioquímica de Macromoléculas, for calling our attention to this protein synthesis inhibitor and providing us samples both of narciclasine andNarcissus bulbs. We also greatly appreciate Dr B. Rodriguez and Dr F. M. Panizo of the Instituto de Química Orgánica (Departamento de Productos Naturales) for their valuable help in isolation and characterization of narciclasine, and for laboratory facilities. The work has been partially supported by the Comisión Asesora para la Investigación Científica (Spain). A.S. has a fellowship awarded by the Instituto de Cultura Hispánica, Spain.     

Magnetic order close to superconductivity in the iron-based layered LaO1-xFxFeAs systems

Following the discovery of long-range antiferromagnetic order in the parent compounds of high-transition-temperature (high-T(c)) copper oxides, there have been efforts to understand the role of magnetism in the superconductivity that occurs when mobile 'electrons' or 'holes' are doped into the antiferromagnetic parent compounds. Superconductivity in the newly discovered rare-earth iron-based oxide systems ROFeAs (R, rare-earth metal) also arises from either electron or hole doping of their non-superconducting parent compounds. The parent material LaOFeAs is metallic but shows anomalies near 150 K in both resistivity and d.c. magnetic susceptibility. Although optical conductivity and theoretical calculations suggest that LaOFeAs exhibits a spin-density-wave (SDW) instability that is suppressed by doping with electrons to induce superconductivity, there has been no direct evidence of SDW order. Here we report neutron-scattering experiments that demonstrate that LaOFeAs undergoes an abrupt structural distortion below 155 K, changing the symmetry from tetragonal (space group P4/nmm) to monoclinic (space group P112/n) at low temperatures, and then, at approximately 137 K, develops long-range SDW-type antiferromagnetic order with a small moment but simple magnetic structure. Doping the system with fluorine suppresses both the magnetic order and the structural distortion in favour of superconductivity. Therefore, like high-T(c) copper oxides, the superconducting regime in these iron-based materials occurs in close proximity to a long-range-ordered antiferromagnetic ground state.     

Depth of a strong jovian jet from a planetary-scale disturbance driven by storms

The atmospheres of the gas giant planets (Jupiter and Saturn) contain jets that dominate the circulation at visible levels. The power source for these jets (solar radiation, internal heat, or both) and their vertical structure below the upper cloud are major open questions in the atmospheric circulation and meteorology of giant planets. Several observations and in situ measurements found intense winds at a depth of 24 bar, and have been interpreted as supporting an internal heat source. This issue remains controversial, in part because of effects from the local meteorology. Here we report observations and modelling of two plumes in Jupiter's atmosphere that erupted at the same latitude as the strongest jet (23 degrees N). The plumes reached a height of 30 km above the surrounding clouds, moved faster than any other feature (169 m s(-1)), and left in their wake a turbulent planetary-scale disturbance containing red aerosols. On the basis of dynamical modelling, we conclude that the data are consistent only with a wind that extends well below the level where solar radiation is deposited.