Showing papers by "Heidelberg University published in 1975"

Spontaneous mutation in man.

Abstract: Mutation is one of the basic phenomena of life. Without mutation, the gradual development of life from inorganic material would have been impossible, and the evolution of living beings from the first groups of molecules in which a primitive, information-carrying unit cooperated with an energy gaining device59 up to the present diversity of highly refined living organisms could not have occurred. Therefore, one would expect that mutation, and especially “spontaneous” mutation, i.e., that occurring naturally and without any detectable external reasons, would attract the research activity of many biologists, especially geneticists. Surprisingly, however, this is not the case. In most experimental studies—for example, on microorganisms, Drosophila or the mouse—research on spontaneous mutation is being carried out more or less as a sideline of other work, and the results are widely scattered.

Mode of action of sodium nitroprusside on vascular smooth muscle

Abstract: 1. Sodium nitroprusside is a potent relaxant of smooth muscles with a predominantly tonic response, e.g. rat aorta contracted by noradrenaline angiotensin II, Phe2-Lys8-vasopressin, BaCl2, or KCl, and guinea-pig tracheal smooth muscle contracted by carbachol. 2. Smooth muscle preparations from the splanchnic region and with varying degrees of phasic contractility are less sensitive and develop tachyphylaxis (portal vein, duodenum of the rat) or are unresponsive to sodium nitroprusside (vas deferens, uterus of the rat). 3. Cardiac auricles of the guinea pig are not affected by sodium nitroprusside in either frequency or amplitude of spontaneous contractions. 4. Sodium nitroprusside causes a parallel shift of the dose-response curve of rat aorta to noradrenaline to the right and reduces the maximum response. 5. The drug has no blocking or stimulant effect on α-or β-adrenoceptors, respectively. 6. Sodium nitroprusside inhibits the contractile response of calcium-depleted depolarized rat aorta to extra-cellular calcium. Like verapamil, it inhibits the increment in 45calcium uptake of rabbit aorta elicited by K+. Sodium nitroprusside significantly reduces 45calcium binding by microsomes prepared from rabbit aorta. 7. Rabbit aorta was incubated with lanthanum chloride to prevent calcium influx; sodium nitroprusside reduced the maintained rapid contraction phase in response to noradrenaline which is believed to be based on the intracellular activation of calcium. 8. In rat aorta, cellular cAMP and ATP levels were not found to be affected by the drug. 9. Rabbit aorta, “skinned” by glycerination, is unresponsive to sodium nitroprusside. 10. It is concluded that sodium nitroprusside acts on excitation-contraction coupling predominantly in tonic smooth muscle by interfering with both the influx and the intracellular activation of calcium.

Heavy metals in sediments of the rhine and elbe estuaries: Mobilization or mixing effect?

Abstract: On their way from the Rhine estuary into the North Sea and Dutch Wadden Sea, Rhine sediments “lose” large portions of their original heavy metal concentrations. Until now these losses were explained by a mobilization process, solubilization — the decomposition products of organic matter form soluble organometallic complexes with the metals of the sediment. Our investigations of the sediments of the Elbe clearly indicate that a mixing process, whereby highly polluted Elbe sediments mix with relatively non-polluted North Sea sediments, rather than solubilization, is the cause of the dilution of heavy metals in the sediments of the Elbe estuary. Because of the similarity of the Elbe data with those from the Rhine River, we propose that a mixing process is also effective in the Rhine estuary and adjacent North Sea areas. The mechanism by which heavy metals are “diluted” is important to the marine ecosystem. In the mixing process proposed in this paper, the heavy metals fixed to the suspected material are trapped in bottom sediments of the marine environment, whereas solubilization would increase the concentration of heavy metals in the sea water and thus they would be more available for uptake by aquatic organisms.

Quantum-statistical approach to gross properties of peripheral collisions between heavy nuclei

Abstract: Non-equilibrium quantum-statistical mechanics is applied to peripheral collisions between heavy nuclei (A≳40) where a large number of degrees of freedom are involved during the process. By eliminating the relative motion from the explicit consideration, the transitions between different channels are determined by a Liouville equation with timedependent coupling matrix elements. The introduction of subsets of channels (coarse graining) leads to the definition of macroscopic variables which correspond to observable quantities. The equation of motion for the macroscopic variables become irreversible by assuming the values of the coupling matrix elements to be randomly distributed. The validity and possible applications of the resulting master equations are discussed.

RAMAN Spectra of Peroxides

Abstract: The RAMAN spectra of solid polycristalline samples of peroxides of alkali metals, alkaline earths, and two group II transition metals have been measured. The OO stretch vibration produces an intense band in the expected frequency region of 750 to 850 cm−1. The observation of a weak band at 815 cm−1 indicates the existence of BeO2. Frequency shifts in the hydrates of alkali and alkaline earth peroxides support different water association.

Dna content and evolution in the microseridinae

Abstract: A B S T R A C T Relative 2C nuclear DNA contents were microphotometrically determined from nuclei isolated from eight species of Microseris, four species of Agoseris, and Phalacroseris Bolanderi. The thirteen species are diploid (2n = 18) western North American members of the subtribe Microseridinae, tribe Cichorieae, of the family Compositae. A 7.7-fold variation in DNA content was detected. Phalacroseris has the highest DNA content and Agoseris heterophylla has the lowest. Within the genera Microseris and Agoseris, a 2.8- and 3.1-fold range in DNA content was detected. The higher values were from perennial species, and the lower values were from annual inbreeding species. Both evolutionary increases and decreases in nuclear DNA content have apparently occurred during the differentiation of the subtribe. DNA CONTENT per nucleus and per chromosome varies over 100-fold among vascular plants (Rees, 1972; Rees and Jones, 1972; Sparrow, Price, and Underbrink, 1972; Price, Sparrow, and Nauman, in press). Although polyploidy is responsible for some of the variation in nuclear DNA content, an approximate 65-fold range is found among diploid

RNA Polymerase B from Drosophila melanogaster Larvae

Abstract: A purification procedure is described by which we obtained DNA-dependent RNA polymerase B (or II) from third-instar larvae of Drosophila melanogaster in essentially pure form. The enzyme is similar to the analogous polymerases from other eukaryotes in its enzymic and structural properties. It preferentially transcribes DNAs containing single-stranded regions, and it is inhibited by low amounts of the toxin alpha-amanitin; 50% inhibition occurs at an alpha-amanitin concentration of 0.03 mug/ml. Dodecylsulfate-polyacrylamide gel electrophoresis resolves the purified Drosophila polymerase B into ten polypeptides with molecular weights as follows: 1 (174000), 2 (137000), 3 (34000), 4 (22000), 5 (18000), 6 and 7 (16000), 8 (15000), and 9 and 10 (less than 15000). The relative amounts of polypeptides 1-4 were constant at molar ratios of approximately 1:1:1:2 in different preparations of the enzyme, while the amounts of polypeptides 5-10 showed more variation. An antiserum directed against the Drosophila RNA polymerase B inhibited the activity in vitro of the B enzymes from Drosophila, yeast, and calf thymus. However, only the Drosophila enzyme gave a precipitin reaction with the antiserum. When the antiserum was added to Drosophila RNA polymerase B at different stages of the purification, the resulting precipitates were found to contain nearly constant proportions of seven of the ten polypeptides present in the purified enzyme.

Fine and hyperfine structure of the 2 2 P term of 7 Li; determination of the nuclear quadrupole moment

Abstract: Microwave transitions between the Zeeman split doublet states 22 P 1/2 and 22 P 3/2 of7Li have been measured using the optical double resonance method. The fine structure separation was determined to bev fs=10.053.184(58) MHz. The hyperfine structure was well resolved and led to considerably improved precision of the diagonal coupling constantsa 1/2=45.914(25) MHz,a 3/2=−3.055(14) MHz,b=−0.221(29) MHz. Furthermore, the contact, spin dipolar and orbital magnetic hyperfine constants are evaluated using additional results from level crossing experiments, which are more sensitive on the non-diagonal magnetic hyperfine constanta 3/2,1/2. The results are in good agreement with recent theoretical calculations. The nuclear quadrupole moment is derived fromb to beQ(7Li)=−41(6) mbarn.

Localisation of peroxidase isoenzymes in protoplasts and cell walls of Nicotiana tabacum L.

Abstract: Upon disk-electrophoresis with guaiacol as a substrate the peroxidase-isoenzymes of Nicotiana tabacum (L.) were localized on the gels in two anodic and two cathodic groups. By preparation of protoplasts and isolation of cell walls it was possible to show that only cathodic enzymes are located in the protoplasts in measurable amounts, whereas all the isoenzymes, anodic and cathodic, can be found associated with cell walls. The different groups of isoenzymes are bound to the cell wall in different ways as evidenced by differences in their extration. It seems possible that different biological functions are associated with the different groups of isoenzymes.The isoenzyme patterns of different organs and tissues of tobacco show qualitative differences only in the anodic (i.e. wall located) isoenzymes. It is suggested that the ontogenetic change in peroxidase-patterns is direct evidence of biochemical differences in the cell walls of the different tissues and organs.

Studies on intracellular transport of secretory proteins in the rat exocrine pancreas. II. Inhibition of antimicrotubular agents.

Abstract: The possible role of microtubules and microfilaments in the secretory process of the rat exocrine pancreas was analysed in vitro using isolated pancreatic lobules. Colchicine and vinblastine as microtubule inhibitors, hexylene glycol as a microtubule stabilizer, and cytochalasin B as a disruptive agent for microfilaments were used in increasing concentrations to test their effects on protein synthesis, intracellular transport, zymogen discharge, and cellular respiration. Colchicine only at 10(-2) M concentrations inhibits protein synthesis, while vinblastine inhibits at 10(-6) and 10(-5) M by 20% and at 10(-4) M by 55%. A similar inhibition is observed with 1.5% concentrations of hexylene glycol while cytochalasine B at 1,5 and 10 mug/ml is without effect on protein synthesis. Colchicine and vinblastine have their major effects on intracellular transport both in secretion studies and cell fractionation experiments. Colchicine in concentrations between 10(-3) to 10(-5) M inhibits discharge of newly synthesized proteins by 50%, while vinblastine shows a dose-response relationship of 40% inhibition of 10(-6) M to 90% at 10(-4) M. Discharge of amylase is uniformly reduced by 30% by both colchicine and vinblastine in the whole dose range. The pronounced effect of colchicine and vinblastine is evident in cell fractionation studies: both drugs inhibit the disappearance of protein radioactivity from microsomes and its appearance in zymogen granules; similarly the peak radioactivity in smooth microsomes (Golgi) appears delayed. No differential effect on the secretory process was observed with 1.5% concentrations of hexylene glycol or cytochalasin B at 1.5 and 10 mug/ml concentrations. A fines tructural analysis of microtubules and microfilaments in the exocrine pancreatic cell reveals their distribution in all parts of the cytoplasm and in relation to all cell organelles. Both systems (microtubules, microfilaments) seem to be connected, at least in certain areas of the cytoplasm and at the plasma membrane. The reduction of transport efficiency by microtubule inhibitors results in a deposition of secretory material in the cristernal space of the rough endoplasmatic reticulum, which leads to the formation of paracrystals. Colchicine at 10(-3) M concentrations leads to an enlargement of condensing vacuoles in the Golgi complex.

The structural organization of the kidney of the desert rodent Psammomys obesus.

Abstract: The architecture of the desert rodent Psammomys obesus has been studied by means of standard histologic procedures and by single nephron injections. As other rodent kidneys (rat, mouse), the Psammomys kidney consists of two types of nephrons, 66% short looped and 34% long looped nephrons. The cortex is composed of 4 to 5 layers of glomeruli, which lie closely put together, the glomeruli often touch each other. The superficial and the midcortical glomeruli give rise to short looped neophrons, the juxtamedullary to long looped nephrons. In the strongly developed medulla the inner stripe shows the most striking pattern. It consists of two distinct compartments, that of the giant vascular bundles and that of the interbundle regions. The giant vascular bundles consist of about 8 to 14% arterial vasa recta and 39 to 47% venous vasa recta; furthermore they include the thin descending limbs of the short loops of Henle which amount to 44 to 51% of the bundle structures. The tubules of the interbundle regions surround the bundles in a regular pattern. The inner zone is almost completely surrounded by the renal pelvis; the long broad papilla protrudes into the ureter. The thin descending limbs of short looped nephrons traverse the inner stripe inside the giant vascular bundles. Leaving the bundles they turn back within the inner stripe; their ascending limbs lie in the interbundle region. Both limbs of the long loops of Henle run in the interbundle region, together with the ascending limbs of the short loops and the collecting ducts. The long loops penetrate deeply the inner zone. Many bends are found near the tip of the papilla. The renal pelvis has a very specialized form. It penetrates the inner stripe with many complexely shaped extensions, which surround the giant vascular bundles. Large parts of the bundles with their thin walled structures are thus separated from the pelvic urine only by a single layer of cuboidal epithelium. The possible functional importance of the described specializations of the Psammomys kidney (giant vascular bundles, large inner zone, special shape of the renal pelvis) for the urine concentrating and urea recyclng mechanisms is discussed.

Budding and cleavage division of tobacco mesophyll protoplasts in relation to pseudo-wall and wall formation.

Abstract: Two saline media, differing primarily in the presence or absence of NH4 + but also in the concentration of sucrose, were developed for culture of tobacco (Nicotiana tabacum L.) mesophyll protoplasts. In the R0.6 medium, which does not contain NH4 + and only 1 g/l sucrose, protoplasts divide 2–3 times by budding and form only a pseudo-wall, i.e. a nonrigid structure containing polysaccharides. Later the cells degenerate, and sustained division does not take place. In the W 0.6 medium, which contains NH4 + and 30 g/l sucrose, the protoplasts form a rigid wall and divide by cleavage of the cells. After a few divisions, the walls of practically all of the newly formed cells degenerate into pseudo-walls, and the divisions cease. Only a few cells keep a wall, continue to divide, and form colonies. A very high frequency of colony formations from protoplasts is obtained by culturing protoplasts for a week in R0.6 or W 0.6 and then diluting the culture with a sugar medium. A detailled study of the inorganic and organic components of the saline media showed a strong interaction between the nitrogen supply and the cytokinin requirement. The advantages of the saline media in obtaining cell colonies from protoplasts, the problems associated with budding-type division, the causes of the cessation of division when no complete wall is formed, and the conditions necessary for wall formation are discussed.

Importance of the wall for cell division and in the activity of the cytoplasm in cultured tobacco protoplasts.

Abstract: When tobacco (Nicotiana tabacum L.) mesophyll protoplasts are cultivated in a medium in which osmotic pressure is maintained by using salts instead of sugars they divide 2-3 times although they never form a rigid wall which could be separated from the cytoplasm by the use of plasmolysis. Only a non-rigid pseudo-wall is present during division, showing that a rigid wall is not required for cell division. Diluting the salt medium with 5 volumes of sugar medium leads to the formation of a rigid wall as well as the initiation of sustained divisions. It is proposed that the complete wall is the place of synthesis of the substance(s) necessary for the division activity of the cytoplasm.

Thrombosis and intracranial tumors.

Abstract: 334 necropsy reports of intracranial neoplasm from an autopsy material over 13 years were reviewed to study the relationship of intracranial tumors to vascular thrombosis. The incidence of venous thrombosis in intracranial tumors was found to be 27.5% while that of a control group without malignancies taken at random from the autopsy material was 17%. The difference gives a statistical significance of P less than or equal to 0.05. The parameters of sex, surgical intervention, the malignancy and the histological type of the tumor apparently dod not affect thrombus formation to a statistically significant degree. There is increased thrombosis frequency with increasing age. The presence of hemiparesis or hemiparalysis does not affect the incidence of thrombosis. However, it determines to a great degree the lateralization of the thrombus.

Porokeratosis [correction of Parakeratosis] Mibelli and skin carcinoma: a critical review.

Abstract: The literature on parakeratosis Mibelli (PM) is revised critically with respect to the development of skin carcinoma. The incidence of epidermal malignancies in PM lesions is 7% (17 of 250 cases). An influence of X-ray treatment is not excluded in 4 cases with tumors in PM.

Morphological studies in tissues surrounding alloarthroplastic joints.

Abstract: Histological, histochemical and ultrastructural studies were done on soft tissue surrounding alloarthroplastic joints. In 38 cases a prosthesis of the hip joint and in 2 cases of the knee had to be exchanged and replaced. In most of the cases the reoperation became necessary because the anchoring of the prosthetic parts in the bone loosened. Up to 18 months after the first operation infection was responsible for the malfunctioning in some cases. Other complications were luxation and material faults. The morphological changes are determined by the tissue reaction to the different alloplastic materials used and by the time interval they remained in the organism. The large polymerized acrylic cement particles are phagozytosed by multinucleated foreign body giant cells. About 12 months following the implantation of the artificial joints small double refractile particles appear and evoke characteristic morphological changes. The particles are abraded by the continuous friction of the moving alloplastic or metallic surfaces of the prostheses. Usually they are phagozytosed by histiocytes, which form large granulomas and undergo degenerative changes as is indicated by the ultrastructural and histochemical findings. These alterations are more pronounced and occur sooner in prosthesis with parts (rotation ball or cup.) fabricated by polyester than in those made by polyethylene. The abraded particles not only are transported to the inguinal lymphnodes, but also to the tissue between prostheses and bone, where they induce the same morphological changes as in the capsule. Hence the fibrous membrane separating bone and prostheses increases in width, and the spongy bone is partially destroyed by the proliferating histiocytes. It is assumed that by impairing the anchoring this foreign body reaction to the abraded alloplastic particles is the leading cause of the loosening of this kind of artificial joints.

Zum Mechanismus des Abbaus von Polymeren in Lösung durch Ultraschall

Abstract: Die Abbaureaktion von Dextran durch Ultraschall wurde im Molekulargewichtsbereich von 30 000 bis 90 000 in verschiedenen Losungsmitteln untersucht. Die Abbauprodukte wurden durch ihre Molekulargewichtsverteilungen, die mit Hilfe von Chromatographie an porosem Glas bestimmt wurden, charakterisiert. Aus den Ergebnissen der Untersuchungen konnte abgeleitet werden, das die Abbaureaktion nach erster Ordnung verlauft, die Abbaukonstante proportional dem Molekulargewicht ist, und die Molekule bevorzugt in zwei nahezu gleichgrose Bruchstucke zerfallen. Die Art des Losungsmittels hat dabei einen erheblichen Einflus auf die Abbaukonstanten; es wurde gefunden, das diese der molaren Verdampfungsenthalpie des Losungsmittels direkt proportional sind. Der Einflus der Konformation des Polymeren auf die Abbaukonstanten wurde studiert, wobei sich ergab, das mit einer Aufweitung der Polymerknauel die Abbaukonstanten groser wurden. Die Ergebnisse bestatigen die allgemeine Auffassung, das die Kavitaten, die bei der Ultrabeschallung entstehen, fur die Abbaureaktion verantwortlich sind. Eine eindeutige Entscheidung, ob die inhomogenen Stromungsfelder oder die Stoswellen, die bei der Implosion der Kavitaten entstehen, fur den Molekulbruch letztlich masgebend sind, kann mit den bisher vorliegenden Ergebnissen nicht getroffen werden. Der Befund, das aufgeweitete Knauel leichter abgebaut werden, spricht fur den Stoswellenmechanismus. Andererseits wird ein Modell fur die Abbaureaktion angegeben, in dem beide Effekte insoweit zusammenwirken, das die inhomogenen Stromungsfelder das Polymerknauel zunachst strecken und die nachfolgende Stoswelle den Molekulbruch bewirkt. The degradation reaction of dextran by the action of ultrasound was investigated within the molecular weight range from 30 000 to 90 000 in different solvents. The degradation products were characterized by their molecular weight distributions obtained by chromatography on porous glass. From the results of the experiments it could be shown that degradation follows a first order reaction, that the rate constant of degradation is proportional to the molecular weight, and that the molecules break preferentially into two parts of approximately equal size. The nature of the solvent has a considerable effect on the rate constants, which could be shown to be proportional to the enthalpy of vaporization of the solvent. The effect of polymer conformation on the degradation constants was studied and it was found that the degradation constants increase with expansion of the polymer coils. The experimental results confirm the general assumption, that the cavities, which are caused by ultrasound, are responsible for the degradation reaction. It is not possible, however, to conclude from the experimental results known so far, whether the inhomogenous flow fields or the shock waves, which arise from the collapse of cavitation bubbles, are responsible for the rupture of the molecule. The experimental result, that expanded polymer coils are more easily degraded. favours the mechanism which implies shock waves. Furthermore, a model in which both effects are acting together, in the way that the inhomogeneous flow fields at first stretch the polymer coil, whereas the shock wave, which immediately follows, breaks the molecule, is suggested to explain the rupture of the molecules.

Lattice dynamics of sapphire (corundum)

Abstract: By inelastic neutron scattering the phonon dispersion of sapphire (α — Al2O3) has been measured along the two principal symmetry directions. Along the direction of threefold symmetry 20 different phonon modes are to be expected. From these 4 quasilongitudinalΛ1 andΛ2 modes each and 5 quasitransverseΛ3 modes could be identified making use of the selection rules for the structure factor. The highest measured phonon frequencies range up to 26 THz.