Projections of bulbar reticular nuclei and raphe nuclei to lobules VI and VII of cat cerebellar cortex]

Injections of horseradish peroxidase were made in lobules VI and VII of the cerebellar vermis (in the Cat). Serial frontal sections of the brain stem reveal that the lateral and paramedian nuclei were essentially projected onto lobule VI, and the projections from the raphe nuclei onto lobule VII.     

Evidence that superoxide radicals are involved in the hemolytic mechanism of phenylhydrazine

Summary Phenylhydrazine produces in the red blood cell the same effect as the enzymic system xanthine oxidase-xanthine, a superoxide radical generator system. Both effects are inhibited by the enzyme superoxide dismutase.This work was supported in part by grants Nos. 1045 and 3243 of Oficina Técnica de Desarrollo Científico y Creación Artística de la Universidad de Chile.     

A Revolution that never happened

If we define scientific revolutions as changes of scientists' ontologies, types of causal explanation, and paradigmatic types of methods and instruments, Antoine-Laurent Lavoisier's contribution to chemistry did not amount to a scientific revolution. Contrary to the received view that Lavoisier initiated a “chemical revolution,” which is accepted by Chang and Kusch, I argue that Lavoisier shared with the phlogistonists their “flat ontology” of chemical substance, established decades before the 1770s, their types of explaining chemical transformation, and their quantitative methods. Based on my historical reconstruction, I criticize Chang's argument that the late eighteenth-century phlogistic systems and Lavoisier's system belonged to two different theoretical traditions. As a consequence, I also question Chang's argument that the acceptance of Lavoisier's system can be explained in terms of dominance of “compositionism” over “principlism.”     

Specificity and reversibility of insulin binding to isolated thyroid nuclei

Inhibition studies of nuclear binding of labelled insulin by unlabelled insulin, proinsulin and polypeptide hormones (glucagon, GH, TSH) as well as kinetics of binding dissociation suggest that thyroid isolated nuclei specifically, at least pro parte, and reversibly bind to insulin.     

A simple method for counting nuclei in the preimplantation mouse embryo

Summary An easy and rapid method of counting the number of cells in the preimplantation mouse embryo is described. The procedure increases the speed with which large numbers of embryos can be processed using a simple squash technique. Cell numbers are determined by exposing the embryos to the fluorescent DNA-binding dye, Hoechst 33258, removing the zona pellucida and simply squashing the embryo and counting the number of fluorescent nuclei. An increase in fluorescent intensity and maintenance of nuclear conformation of the squashed preparations are greatly improved by the use of the non-ionic detergent Triton X-100. Viability of dye-treated fertilized one-cell and blastocyst stage embryos is maintained at least up to day 13 of pregnancy following transfer of the embryos to the uteri of pseudopregnant recipients. Additional uses for this staining technique are discussed.Acknowledgment. Financial support was provided by NIH Grant HDD-06210 (KME) and by Basil O'Connor Starter Research Grant No. 5-379 from the March of Dimes Birth Defects Foundation (VEP). We thank Steven Halpern for help with the photography and Jon Flax for expert technical assistance.     

A simple method for counting nuclei in the preimplantation mouse embryo

An easy and rapid method of counting the number of cells in the preimplantation mouse embryo is described. The procedure increases the speed with which large numbers of embryos can be processed using a simple squash technique. Cell numbers are determined by exposing the embryos to the fluorescent DNA-binding dye, Hoechst 33258, removing the zona pellucida and simply squashing the embryo and counting the number of fluorescent nuclei. An increase in fluorescent intensity and maintenance of nuclear conformation of the squashed preparations are greatly improved by the use of the non-ionic detergent Triton X-100. Viability of dye-treated fertilized one-cell and blastocyst stage embryos is maintained at least up to day 13 of pregnancy following transfer of the embryos to the uteri of pseudopregnant recipients. Additional uses for this staining technique are discussed.     

A rapid method for the fractionation of avian blood cell nuclei

Summary Red blood cell nuclei from avian anaemic blood have been fractionated by rate sedimentation on discontinous sucrose gradients into fractions which can be distinguished both by their RNA synthesizing ability and by their morphology as revealed by electron microscopy.Acknowledgment. We wish to thank H. Gitay for the electron micrographs. This work was supported by grants from the University of Cape Town Research Committee and the Council for Scientific and Industrial Research.     

Stereotaxic localization of amygdaloid nuclei in rats from weaning to adulthood

Zusammenfassung Stereotaxische Koordinaten werden für die Setzung von Läsionen in den Amygdalen von Ratten (54–236 g Körpergewicht) ermittelt. Die Daten ermöglichen auch die Extrapolation von Strukturen, die in dieser Mitteilung nicht erwähnt wurden.

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This investigation was supported by U.S.P.H.S. Grant No. HE 06975 of the National Heart Institute.     

Estrogen binds to hypothalamic nuclei of androgen-insensitive (tfm) rats

Summary Androgen-insensitive (tfm) rats possess a nuclear-estrogen binding system in the brain that is similar to that of wild-type control males. In these mutant rats, radiolabeled estradiol was bound predominantly to hypothalamic nuclei and this binding was of limited capacity.This research was supported by grants Nos HD-13957 and HD-14726 from the National Institute of Child Health and Human Development.     

A mechanism for macromolecular transfer from glia to neuron cell body in crayfish

Summary Small extrusions of glial cytoplasm are endocytosed by neuron cell bodies of the crayfishProcambarus. Vesicles are double walled with the external membrane issuing from the neuron and the internal one from the glia. This could be a system for the transfer of glial cytoplasmic free proteins to neurons.     

A method for injection and transplantation of nuclei and cells inDrosophila eggs

Summary Microinjection ofDrosophila eggs using the principle of thermal expansion is described. The eggs, mounted on cover slips with adhesive, are slightly dried to avoid the formation of exudate and then covered with fluorocarbon oil. Injections are made with a specially designed electrically controlled micropipette.     

A note on the polytene nuclei in the fat body ofDrosophila larvae

Resumen Los nucleos de las células grasas de larvas deDrosophila melanogaster, contienen cromosomas politénicos cuya ultrastructura es similar a la que presentan los cromosomas en las glandulas salivales. Bandas gruesas, finas, y algunas «minibandas» se hallan separadas por regiones claras compuestas por fibrillas con un diametro de 60–80 Å. El nucleolo constituido por elementos granulares periféricos y fibrilares centrales, presenta un aspecto similar al nucleolo de glandulas salivales.

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The work reported in this paper was undertaken during the tenure of a research fellowship awarded by the Instituto Nacional de Farmacología y Bromatología, Argentine.

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This work was supported by a research grant from the Population Council. Inc. New York.     

一种动态的客户端负载均衡机制

互联网应用的并发用户数量不仅多变并且这种变化常常不可预测．将系统容量配置为固定值的惯用做法在面临多变的请求时常常会导致两种结果,一种是因为配置过低而弓l起用户的不满,另一种则因为配置过高而造成计算资源的浪费．而通过运用云架构按需提供、按使用收费的能力,系统具有了实时地按需配置计算资源的能力．然而静态的客户端负载均衡方法作为一种主要的负载均衡技术很难适应云架构条件下更加易变的集群结构．本文提出了一种动态的客户端负载均衡机制．通过引入分布式的集群视图更新、控制流等技术,该机制在保持客户端负载均衡机制分布式、可伸缩性强的基础上,又为集群节点的动态加入与退出和负载均衡策略的动态调整提供了有效的支持．同时,本文分析了该机制在一个开源JEE应用服务器PKUAS中的关键实现问题,并通过实验从多方面验证了该机制的有效性．     

The contribution of noncatalytic phosphate-binding subsites to the mechanism of bovine pancreatic ribonuclease A

The enzymatic catalysis of polymeric substrates such as proteins, polysaccharides or nucleic acids requires precise alignment between the enzyme and the substrate regions flanking the region occupying the active site. In the case of ribonucleases, enzyme-substrate binding may be directed by electrostatic interactions between the phosphate groups of the RNA molecule and basic amino acid residues on the enzyme. Specific interactions between the nitrogenated bases and particular amino acids in the active site or adjacent positions may also take place. The substrate-binding subsites of ribonuclease A have been characterized by structural and kinetic studies. In addition to the active site (p₁ ), the role of other noncatalytic phosphate-binding subsites in the correct alignment of the polymeric substrate has been proposed. p₂ and p₀ have been described as phosphate-binding subsites that bind the phosphate group adjacent to the 3′ side and 5′ side, respectively, of the phosphate in the active site. In both cases, basic amino acids (Lys-7 and Arg-10 in p₂ , and Lys-66 in p₀ ) are involved in binding. However, these binding sites play different roles in the catalytic process of ribonuclease A. The electrostatic interactions in p₂ are important both in catalysis and in the endonuclease activity of the enzyme, whilst the p₀ electrostatic interaction contributes only to binding of the RNA.     

A newTrichoplusia ni antennal receptor neuron that responds to attomolar concentrations of a minor pheromone component

Summary A newly discovered third class of sensillum trichodea on the antenna ofTrichoplusia ni contains an olfactory receptor neuron that responds to (Z)-9-tetradecen-1-ol acetate at 1×10^–18 M. The threshold of this neuron is 100–1000 times lower than the thresholds of two previously described pheromone-sensitive neurons that detect (Z)-7-dodecen-1-ol acetate and (Z)-7-tetradecen-1-ol acetate. The sensitivity and selectivity of this receptor neuron is evidence that (Z)-9-tetradecen-1-ol acetate may be important for sexual behavior.     

A hypothesized unifying mechanism in neural function

Zusammenfassung Es wird die Hypothese aufgestellt, wonach alle nervösen Prozesse auf Ligandenkomplexierung mit Rezeptordisulfiden und/oder Sulfhydrylprotomeren der Nervenmembranen beruhen und diese Prozesse mit Reduktions- bzw. Oxydationsprozessen gekoppelt sein könnten. Lernprozesse würden auf dem gleichen Mechanismus beruhen.

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Approved for publication by the Director of the Research Division, College of Agricultural and Life Sciences. This research was supported in part by research grants No. GB-6580 and No. GB-8756 from the U.S. National Science Foundation, and by funds from the Elm Research Institute, the Wisconsin Department of Natural Resources, the Alleghany Foundation, the Schoenleber Foundation, and the Acme Chemical Co.