摘要:

AbstractIn this article four cases of signal transduction in biology are discussed, ranging from a case which we do understand in molecular detail (genetic induction) through two cases where the fog may be beginning to clear (vertebrate vision and bacterial chemotaxis) to a case where we are still struggling to define the participants of the play (the avoidance response of the fungus Phycomyces).—Although most of the facts presented are not brand new, the juxtaposition of them is perhaps unconventional and may be of interest at least by way of outlining an area of research of some promise. No doubt modern concepts and technologies of chemical and physical research will play a great role in this borderline area between a variety of fields, presenting great challenges to the ingenuity and versatility of the experimente

ISSN:0570-0833    

DOI:10.1002/anie.197200011

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractHigher organisms having anatomically and functionally differentiated organ systems must be able to coordinate biochemical processes within and between the various organs or cells, even under rapidly changing environmental conditions. Hormones play an important part in the regulation processes: they promote numerous metabolic reactions and differentiation processes, and show considerable differences in the speed with which they act. Some hormones act almost instantaneously by stimulating adenyl cyclase and thus initiating the production of adenosine 3′,5′‐monophosphate (cyclic AMP), which passes on the hormone message (“second messenger”) to the intracellular metabolism by modifying enzyme activities. Delayed‐action hormones, mainly morphogenetic hormones, act primarily on the cell nucleus where they induce the synthesis of certain enzymes by activati

ISSN:0570-0833    

DOI:10.1002/anie.197200071

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractThe most important, and almost unique, property of the macrocyclic polyethers (“crown compounds”) is their tendency to form complexes with alkali metal salts and salts with similar cations. Such complexes are held together by electrostatic attraction between the cation and the negative end of the CO dipoles. The stability of the polyether complexes depends primarily upon how well the cation fits into the polyether ring; other factors are the charge density of the cation and—in solution—the solvating power of the medium. Cyclic polyethers have been successfully employed, inter alia, in experiments with ionic compounds in organic solvents and in studies of ion transport in biologica

ISSN:0570-0833    

DOI:10.1002/anie.197200161

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractConsiderably improved possibilities are now available for the investigation of the optical vibrations in lattice compounds by Raman and IR spectroscopy. These spectra can be interpreted on the basis of the models and findings of molecular vibration spectroscopy. For simple lattice types simple frequency equations are found for the optical lattice vibrations with in‐phase vibration motions in all unit cells (wave vector k = 0). As an approximation, the force constants that occur in these equations may be interpreted as stretching force constants. For typical ionic lattices, the influence of Coulomb forces due to the lattice polarization that occurs during the vibrational motion must be taken into account. As is shown by the example of some spinels, the assignment of lattice vibrations can be facilitated by model calculation

ISSN:0570-0833    

DOI:10.1002/anie.197200261

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

摘要:

AbstractWhen an atom is incorporated into a molecule or a crystal, its X‐ray spectrum undergoes characteristic changes, the study of which leads to important information on the nature of the chemical bonding and on the electronic structure in a substance. A number of examples are given to illustrate the possibilities of the X‐ray spectroscopy of bonded atoms. Special attention is given to the displacement of the Kα lines, from which conclusions can be drawn regarding the charge on a bonded atom, as well as to the investigation of the emission bands resulting from valence electron transitions, which yields information on the energy band structure of the solid. X‐ray spectroscopic studies on free molecules and theoretical work on the calculation of the molecular orbitals of simple molecules are finally re

ISSN:0570-0833    

DOI:10.1002/anie.197200341

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197200421

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197200431

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197200441

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197200452

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY

ISSN:0570-0833    

DOI:10.1002/anie.197200472

出版商:Hüthig&Wepf Verlag    

年代:1972

数据来源: WILEY