Thermogenic and lipogenic activities in brown adipose tissue of I-strain mice.

Specific binding of 125I-labelled human somatotropin was demonstrated in isolated hepatocytes from male mice. In the presence of divalent cations (Ca2+ and Mg2+) the binding of 125I-labelled human somatotropin was competitive with ovine prolactin. Scatchard analysis of competition data indicated a KD of 1.4 +/- 0.2 nM and a binding capacity of 13 000 +/- 2000 sites/cell. In the absence of divalent cations and in the presence of EDTA, human and bovine somatotropins were found to be equally effective to displace bound 125I-labelled human somatotropin, while ovine prolactin showed a weak competition. In this case, the binding capacity was 8400 +/- 1500 sites/cell and the KD was 1.1 +/- 0.1 nM.     

Synthesis and phosphorylation of cytoskeleton components in foetal,regenerating and adult normal rat hepatocytes during culture

Summary Detergent insoluble material (DIM) was prepared by gentle treatment with detergent from foetal, regenerating and adult normal rat hepatocytes cultured for various times. It retained to some degree the morphology of the cells. After incubation of intact cells with ³⁵S-methionine, most of the labelled DIM proteins were found to be components of the cytoskeleton. They included several cytokeratins, vimentin and actin. The synthesis rate varied with the age of animals and culture conditions. The high synthetic rate of vimentin in foetal and regenerating hepatocytes could be associated with cell proliferation. No correlation was found between cytokeratin synthesis and hepatocyte growth. Most of the cytoskeleton proteins could be phosphorylated in intact cells and in DIM from cultured hepatocytes. However the degree of phosphorylation of these proteins was not related to their synthetic rate. The decreased phosphorylation level in cultured adult rat hepatocytes could be related to the rapid loss of specific functions.     

Modulation of cyclic nucleotide-independent protein kinase from chick intestine by naturally occurring polyamines and mucopolysaccharides

Summary Chick duodenal mucosa contains an endogenous factor which is capable to inhibit selectively a homologous polyamine-sensitive protein kinase. The inhibitor was partially purified and characterized, and it was found to contain typical mucopolysaccharidic components.Glycosidases digestion studies, selective degradation analysis and spectrophotometric titrations with metachromatic dyes indicated that the inhibitor preparation contained two major moieties identified as heparin-like and heparan sulfate-like structures. In chick intestine the inhibitor was specific for polyamine-sensitive protein kinase since selectively interacted with it and was inert towards other cAMP-independent and cAMP-dependent protein kinases. The inhibitory effect of the endogenous factor was counteracted by naturally occurring polyamines such as spermine. The order of potency of various polyamines was: spermine > thermine spermidine diamines. The release of inhibition by addition of physiological concentrations of spermine was also apparent when using cytosolic proteins as endogenous phosphate acceptors. These results suggest that a possible role of polyamine in the regulation of polyamine-sensitive protein kinase in the intestine is to protect the enzyme from the inhibitory action of endogenous heparinoids.     

Patterns of dispersion, density and dispersal in alpine populations of the land snail Arianta arbustorum (L.) (Helicidae)

In studying populations of the land snail Arianta arbustorum in the eastern Swiss Alps, juvenile and subadult snails were found to be aggregated all the time, while adults were mostly aggregated during summer, the main mating period. The mean size of aggregations was 25 cm × 25 cm but varied, according to the area a grass tuft covered, while the intensity of aggregations was influenced by weather conditions. Densities of 10–15 subadults and 3–6 adults m⁻² were found along ditches and streams, 2–25 subadults and 2–20 adults on uncultivated alpine meadows, while on scree-covered alpine grassland the density of subadults and adults was 0.3–0.5 m⁻². The extent of daily movements varied with microclimatic factors and season and depended on the structure of the habitat. The dispersal rate was greatest in June (2.6 m month⁻¹) and least in August (1.1 m month⁻¹). In summer and autumn, active uphill movements were noted, a process which compensates for the loss of altitude by passive downhill displacements. Roiling down on snowfields and being carried away by avalanches and streams were observed.     

Dilution and acidification effects during the spring flood of four Swedish mountain brooks

The seasonal variation in water chemistry was followed during 1980 and 1981 in four mountain brooks in the southern part of Swedish Lapland. In the area investigated the soil is calcareous and the brook water is very well buffered during the major part of the year, with alkalinity varying between 0.4 and 1.0 milliequivalents per liter and with pH values about 7.5. These years the snow had a pH of approximately 5.2, which was considerably higher than has been reported from adjacent areas in the lower, coniferous region. During snowmelt the water discharge increased drastically, and although the net transport of bicarbonate increased, alkalinity showed low values due to dilution with meltwater. pH decreased, but not further than to 6.3–6.5, far from values reported in 1979 (pH less than 5), apparently due to the comparatively clean snow. A slight deficit in alkalinity, as compared to the nonmarine calcium and magnesium content, points to an acidification impact on the area. During maximum runoff some chemical variables, like aluminium, iron, nitrogen and phosphorus, behaved reversely to what might be expected during dilution and reached maxima in concentrations. It is concluded that the extreme runoff characteristics of high mountain areas make brook water more sensitive to acid precipitation than might be expected when regarding only the calcareous properties of soil and bedrock.     

Structural Genes for a Newly Recognized Acetolactate Synthase in Escherichia coli K-12

Evidence is reported that shows the presence in Escherichia coli K-12 of a newly found acetolactate synthase. This enzyme is the product of two genes, ilvH and ilvI, both located very close to leu. Amber mutations have been found in both genes and therefore their products are polypeptides. Mutations in the ilvH gene cause the appearance of an acetolactate synthase activity which is relatively resistant to valine inhibition and can be separated by adsorption on hydroxylapatite from another activity present in the extract and more sensitive to valine inhibition than the former. A mutant altered in the ilvI gene was isolated among the revertants sensitive to valine inhibition of an ilvH mutant. Such a mutant lacks the resistant acetolactate synthase. A temperature-sensitive revertant of the ilvI mutant contained a temperature-sensitive acetolactate synthase. Thus ilvI is the structural gene for a specific acetolactate synthase. The activity of the ilvH gene product has been measured by adding an extract containing it to a purified ilvI acetolactate synthase, which, upon incubation, became more sensitive to valine inhibition. Conversely, a valine-sensitive acetolactate synthase (the product of the ilvH and the ilvI genes) became more resistant to valine inhibition upon incubation with an extract of a strain containing a missense ilvH gene product.     

The effect of post-heparin lipolytic activity on plasma lipoproteins

Summary Electron microscopy of negatively stained plasma shows that intravenous administration of heparin to healthy humans results in a fast degradation of very low density lipoproteins (VLDL), which are very rich in triglycerides (50% w/w). VLDL are also rapidly digested by post-heparin lipolytic activity when serum from non-heparinized subjects is incubated at 27°C in vitro with post-heparin serum of healthy controls.Abbreviations VLDL very low density lipoproteins - LDL low density lipoproteins - HDL high density lipoproteins - LP-X lipoprotein-X, abnormal lipoprotein characterizing obstructive jaundice     

Kinetics of denaturation of DNA

The kinetics of denaturation of DNA have been studied by relaxation techniques. Examination of the terminal relaxation times for a variety of DNA's under a variety of conditions has shown that DNA denaturation is principally a hydrodynamically limited process. Measurements within the helix–coil transition have demonstrated that the experimentally measured terminal relaxation times are a function of the following: (1) position in the helix–coil transition; (2) ionic strength of the solvent; (3) solvent viscosity; (4) DNA concentration; (5) molecular weight; (6) number and position of single-strand breaks. The dependence of the terminal relaxation time on the above mentioned factors can be attributed to hydrodynamic effects. Thus a hydrodynamic model for DNA unwinding is required. The model which best fits the data involves the assumption of a rotational frictional coefficient independent of molecular weight. This assumption is suggested by the fact that the relaxation time is proportional to the first power of the molecular weight.     

Die Beziehung zwischen Mitochondrienmorphologie und Aktivitätsdauer verschiedener Flugmuskelfasern von Locusta migratoria L.

Zusammenfassung Die indirekten und direkten Flugmuskelfasern der Wanderheuschrecke enthalten parallel und voneinander getrennt verlaufende Myofibrillen. In den interfibrillären Räumen liegen zahlreiche, säulenförmig aneinandergereihte Mitochondrion, ein dichtes endoplasmatisches Retikulum und Tracheolen. In Höhe der A-I-Band-Grenzen befindet sich ein charakteristisches retikuläres System, dessen Queranordnung als Diade zu bezeichnen ist. Die chromatinreichen Kerne liegen peripher dicht unter dem Sarkolemm.Sowohl bei den indirekten als auch bei den direkten Flugmuskelgruppen kommt es im Verlaufe des Dauerfluges zu Transformationen der Mitochondrien, die sich in einer erheblichen Schwellung und in einer Umwandlung der Cristae zu Tubuli äußern. Diese Umwandlung wird als intramitochondriale Kompensation aufgefaßt, um das Verhältnis von Oberfläche der inneren membranösen Phase zum Volumen der inneren wäßrigen Phase — d. h. die spezifische Oberfläche — möglichst konstant zu halten. Eine Vesikulation der Tubuli könnte der morphologische Ausdruck für eine Dekompensation sein, da dann der Zusammenhang der äußeren wäßrigen Phase verlorengeht.Die Mitochondrien verschiedener Muskeln reagieren nicht synchron auf die Dauerbelastung, sondern ausgesprochen belastungs- und funktionsspezifisch: Zunächst transformieren sich die Mitochondrien der indirekten, dann erst die der direkten Flugmuskelgruppen, und der anfängliche Schwirrflug geht während fortschreitenden Dauerfluges in einen Flatterflug über. Die unterschiedlichen Erschöpfungszeitpunkte der indirekten Flugmuskeln werden durch die jeweils spezifische Funktion und die ontogenetische Entwicklung erklärt.     

On the History of Men and Genocide

A historical and psychological study of genocide is presented in which special emphasis is given to modern manifestations of this phenomenon. The policy of eradication of the Jews by the Hitler regime is considered as an example of genocide in the twentieth century. The psychopathology of genocide and the complex relationships among aggressors, victims and witnesses are elaborated. Inferences are drawn from past and present patterns of genocide that may provide some leads to the future. It is now possible to envisage an all-consuming genocide unless nations can learn to live together, not necessarily in unity but in diversity.