摘要:

AbstractMost intracellular enzymes are made up of several identical or different subunits. The more remote any two organisms are phylogenetically, the greater will be the differences in amino acid sequence of a given enzyme. Nevertheless, numerous examples exist of specific association between chemically different subunits, or even of the formation of enzyme chimeras. They span not only the boundaries between related organisms but also the deep rift between prokaryotic and eukaryotic cells. Exchange of subunits between enzymes of similar activity but differing origin can be rationalized by assuming enzymes to posses functionally defined types of three‐dimensional structure

ISSN:0570-0833    

DOI:10.1002/anie.197601811

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractHalobacteria are extremely specialized organisms. They live exclusively in saturated solutions of common salt. The cell membrane of these bacteria exhibit insular regions which can be isolated by membrane fractionation. These regions consist of a lipid matrix containing bateriorhodopsin molecules in a hexagonal crystalline arrangement. Bacteriorhodopsin is a deep purple retinal‐protein complex (“purple membrane”). The purple membrane functions as a light energy converter.—How can such a differentiated membrane region arise?In vivostudies on the biosynthesis of the purple membrane showed another cell membrane fraction, the so‐called brown membrane, to be a biosynthetic precursor. Bacterioopsin (the retinal‐free protein) is initially incorporated into the brown membrane and can only form the purple membrane by crystallization in an energy‐dependent reaction after prior reaction with retinal. This reaction is reversible. Removal of the retinal by formation of retinal oxime causes the purple membrane regions to disappear. Reconstitution of the bacteriorhodopsin by addition of retinal regenerates the pu

ISSN:0570-0833    

DOI:10.1002/anie.197601871

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe nervous system is made up of several kinds of cells which should ideally be examined separately in biochemical studies. Since we are not yet able to isolate the different kinds of cells, use is made of cell lines derived from a single cell which are isolated from tumors of the nervous system and which can be reproduced at will in the same way as bacteria. They include cell lines isolated from a mouse neuroblastoma which exhibit some of the properties of nerve cells. Hybrid cells obtained by fusion of mouse neuroblastoma cells with rat glioma cells display even more characteristics of nerve cells. This article considers properties which justify our regarding the hybrid cells as neuron models. Application of the cells to problems of the nervous system is then demonstrated: (1) processing of information arriving in the form of mutually opposing hormonal signals; (2) mode of action of morphine.

ISSN:0570-0833    

DOI:10.1002/anie.197601941

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe prostaglandin synthesis developed in the Woodward Research Institute at Basel serves to provide an unusual look behind the scenes. A candid account is presented of the sometimes tortuous chronological sequence of ideas and experiments during work on a challenging synthesis.

ISSN:0570-0833    

DOI:10.1002/anie.197602071

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe chemical reaction of arthropods to their environment,i.e.their chemical ecology, can be studied particularly well with water beetles.Stenus comma, an aquatic beetle weighing only 2.5 mg, saves itself from drowning with the aid of an alkaloid, and the water beetleIlybius fenestratusdefends itself against small mammalian predators with a compound belonging to the same class. The water beetlePlatambus maculatusemploys a diterpene for precisely the same purpose and the whirligig beetle a norsesquiterpene, which also offers protection against troublesome microorganisms. As chemical artists, the ants can hardly be surpassed. In particular, the myrmecine ants guarantee their food supplies with plant growth substances. Since these compounds, depending upon concentration, can also act as inhibitors, we are confronted with an excellent example of an ecological equilibrium being established with the aid of organic chemicals. Even the little parasitic bombardier beetlePaussus favieriis tolerated, on account of its defensive chemistry, in the nest of the myrmecine antPheidole. In contrast, inorganic compounds are largely responsible for the stability of spiders' webs.

ISSN:0570-0833    

DOI:10.1002/anie.197602141

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197602231

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197602241

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197602251

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197602262

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197602281

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY