Agonist-induced potentiation of acetylcholine sensitivity in denervated skeletal muscle

The entire surface membrane of denervated skeletal muscle is sensitive to the neuromuscular transmitter, acetylcholine (ACh), whereas in innervated muscle only the junctional area is sensitive. It has been proposed that this difference is due to a 'trophic' effect exerted by ACh in innervated muscle to keep the extrajunctional regions of the surface membrane insensitive to its depolarising action. Several studies have demonstrated an agonist-induced potentiation of ACh sensitivity, followed by desensitisation, at the endplate region of normal muscles. The potentiation has been attributed to a cooperative action of ACh on the receptors. Desensitisation of the extrajunctional regions of denervated muscles by ACh has also been described. We now provide evidence that the transmitter itself potentiates the ACh contracture and depolarisation responses of the denervated muscles of the rat in vitro and that it produces this effect by increasing the number of available ACh receptors on the surface membrane.     

手性药物拆分方法的研究

本通过对几种拆分手性药物的方法的列举，比较几种方法，详细介绍了几种方法的特点，以及它们的不同作用。各个方法中又列出了不同的线索，根据这些线索来研究这几种拆分的方法，它们的优缺点以及针对这些缺点的解决方法，最后给出了几个典型的用该方法的实验，以辨别它们的效用。     

Variations in the glycosidic pattern of anthocyanins

Zusammenfassung Neun Glykoside des Pelargonidins wurden durch papierchromatographische Methoden gekennzeichnet. Es war notwendig, die Methode der Zuckeridentifizierung abzuändern, um die Bildung des Kunstprodukts Arabinose zu vermeiden. Einige der neun Glykoside gehören zu neuen Sorten von Anthocyanidinglykosiden, die bisher noch nicht in der Natur entdeckt waren. Die dadurch erklärte Variation im Glykosidformelbild der Anthocyane wird in bezug auf ihre Biosynthese diskutiert.

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Part I: Nature179, 429 (1957).     

Mangroves enhance the biomass of coral reef fish communities in the Caribbean

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs.     

The anthocyanins of roses. Occurrence of peonin

Zusammenfassung Im Gegensatz zu einer früheren Mitteilung konnten wir in den Blumenblättern der Hybriden-Tee-Rose kein Myricetin finden. Delphinidin kam in keiner der geprüften Rosenblüten vor. In roten Varianten erhält man violette Farben bei der «Copigmentation» von Cyanin. Pelargonin ist in gelbroten Rosen vorhanden und Peonin wurde erstmals in der rosa Variante gefunden.     

Flavonoid sophorosides

Zusammenfassung Der seltene Zucker Sophorose konnte mit der Disaccharid-Einheit von Anthozyanen identifiziert werden, die in Arten vonBrassica, Papaver, Phaseolus, Raphanus, Tropaeolum undWatsonia vorkommen, und von Flavonen, die inHelleborus, Petunia, Pisum, Rosa undSolanum vorhanden sind. Es scheint das am häufigsten auftretende, glucosehaltige Disaccharid mit diesen Farbstoffen übereinzustimmen.     

普通化学实验教学改革探索与实践

针对多年来农业院校传统的普通化学实验课教学,进行了教学模式、教学内容、考核方式和实验管理体系等全方位的改革探索和实践.结果表明,经过实验教学改革与实践使学生的实验基本技能、综合素质能力和实验水平有了很大的提高,取得了满意的教学效果.