Licht und Entwicklung — das Phytochromsystem der Pflanzen

In photosynthetic green plants light is the decisive environmental factor. The terrestrial green plant is organized almost ideally in a way so as to absorb and process light quanta. The genetic adaptation to the factor, light, has taken place in the course of the genetic evolution (phylogeny) of terrestrial plants. However, light also affects the individual development (ontogeny) profoundly insofar as the genes which control normal development of a higher plant can only express themselves fully in the presence of light. Thus, the development of a higher plant (“photomorphogenesis”) is characterized by the obligatory interaction between genes and environment (light). The mechanisms of “transduction of light signals”, i.e. the biophysical and molecular events during photomorphogenesis, are described in the present article.     

Ökophysiologische Untersuchungen an Pflanzen der Namib-Wüste

The southern Namib desert has a vegetation cover of mainly succulent plants in which species of the Mesembryanthemaceae are predominant. Climatically this area is characterized by hot and dry days, and cool and humid nights with episodic rainfalls only in winter. In this environment a great number of species perform a crassulaceaen acid metabolism (CAM). The responses of these plants to water stress as well as the regulation of CAM in the natural habitat are described and discussed.     

Botanische Bakteriologie und Stickstoffhaushalt der Pflanzen auf neuer Grundlage

The Science of Nature -     

Die Struktur der Eukaryonten-Chromosomen

Recent models for the organization of the chromosomes of eukaryotes in mitosis and interphase are discussed with respect to their condensation hierarchy. Possible functional interpretations are indicated. At present, an alternating coiling and loop formation, induced by histones and nonhistone proteins, respectively, appears to be the most probable structure. The relationship of DNA properties to chromatin structure and function is also briefly discussed.     

Die Molekularbiologie der Tumorviren

All classes of vertebrates harbor tumor viruses that are capable of inducing either tumors or leukemias. After infection, their genomes become integral parts of the host cell's genetic material (DNA). Many biological functions such as the capacity to code for the synthesis of new proteins and, in particular, the oncogenic property (oncogen) have already been assigned to specific regions (on physical maps) of their DNA.     

Die Funktion der Nierenmembranen

Plasma membranes were isolated from rat kidney and their transport properties for sodium, calcium, protons, phosphate, glucose, lactate, and phenylalanine were investigated. The results demonstrate that the luminal plasma membrane, which is in contact with the primary urine, and the contraluminal plasma membrane, which is in contact with the interstitial fluid, differ in their content of ion-sensitive ATPases and sodium-cotransport systems. This allows conclusions on the mechanism of renal transport in which luminal and contraluminal membranes are arranged functionally in series.