Einflüsse von Licht und temperatur auf den Winterschlaf des Siebenschläfers Glis g. glis (Linnaeus 1766)

Zusammenfassung Vom Sommer 1956 bis zum Frühjahr 1959 wurden mit Siebenschläfern (Glis glis L.) Licht- und Temperaturversuche durchgeführt. Jede Versuchsgruppe war in einem besonderen Versuchsraum untergebracht. Daneben wurden Beobachtungen an wildlebenden Bilchen durchgeführt.Eine Gruppe von Siebenschläfern lebte in einer Voliere im Freien, eine zweite in einem Tierstall mit natürlichen Lichtverhältnissen ohne UV, 2 Tiere waren in einem ähnlichen Raum untergebracht und wurden täglich 1 Std UV-bestrahlt. Diese beiden Tierräume wurden im Winter geheizt (meist über 20° C). Eine Gruppe lebte in einem Klimaraum (wechselnde Temperaturen), in dem täglich 18 Std lang Kunstlicht brannte. Einer letzten Gruppe wurde im Frühsommer die Tagdauer rasch verkürzt, so daß im Hochsommer schon Kurztag herrschte (Raumtemperatur über 20° C).Es wurden untersucht: das Körpergewicht, das Haarkleid, die motorische Aktivität und die Körpertemperatur.Auf Grund der Versuche wurde folgendes festgestellt: Das Körpergewicht bildet bei Tieren, die unter natürlichen Lichtverhältnissen leben, einen ausgeprägten Jahreszyklus. Bei Bilchen im ständigen Langtag war dieser nicht mehr zu erkennen; die Gewichte blieben gleich. Es fand demnach keine Fettspeicherung im Herbst statt. Obwohl das Haarkleid oft gewechselt wurde, blieb stets ein Sommerpelz erhalten. Ebenso war die motorische Aktivität dieser Bilche stets die gleiche, während Normaltiere ein Absinken der Aktivität im Herbst und ein Wiederansteigen im Frühjahr zeigten. Durch frühzeitige Verkürzung der Tagdauer konnten die Tiere schon im Juli veranlaßt werden, Fett zu speichern und ihr Haarkleid zu wechseln.Die Außentemperatur hat nicht den Einfluß auf den Winterschlaf, den man ihr meist zuschrieb. Im Winter schliefen Normaltiere bei Temperaturen um 24° C noch verhältnismäßig tief. Die Schlaftiefe ist allerdings bei niederen Temperaturen größer als bei hohen. Demnach stellt die Temperatur einen wichtigen, sekundären Faktor dar. Normale Sommertiere und Bilche aus dem ständigen Langtag blieben auch bei Kälte wach, wenn genügend Nahrung vorhanden war.Es wird der Schluß gezogen, daß durch die jahreszeitlichen Veränderungen der Tag-Nachtdauer eine endokrine Umstellung stattfindet, die Reservenspeicherung sowie die Winterschlafbereitschaft auslöst. Die Temperatur greift dann erst sekundär ein, indem sie die Tiefe der Lethargie steuert. Trotzdem erfolgt in gewissen Zeitabständen ein spontanes Erwachen.Das Problem Winterschlaf — Torpidity wird an Hand eigener Ergebnisse sowie Untersuchungen anderer Autoren diskutiert und dabei festgestellt, daß ersterer ein komplexes Phänomen darstellt, das vom Organismus wohl vorbereitet wird, während die Torpidity einer Kältestarre vergleichbar ist. Letztere ist daher nicht mit Winterschlaf gleichzusetzen.     

Heritability of adult body height: a comparative study of twin cohorts in eight countries.

A major component of variation in body height is due to genetic differences, but environmental factors have a substantial contributory effect. In this study we aimed to analyse whether the genetic architecture of body height varies between affluent western societies. We analysed twin data from eight countries comprising 30,111 complete twin pairs by using the univariate genetic model of the Mx statistical package. Body height and zygosity were self-reported in seven populations and measured directly in one population. We found that there was substantial variation in mean body height between countries; body height was least in Italy (177 cm in men and 163 cm in women) and greatest in the Netherlands (184 cm and 171 cm, respectively). In men there was no corresponding variation in heritability of body height, heritability estimates ranging from 0.87 to 0.93 in populations under an additive genes/unique environment (AE) model. Among women the heritability estimates were generally lower than among men with greater variation between countries, ranging from 0.68 to 0.84 when an additive genes/shared environment/unique environment (ACE) model was used. In four populations where an AE model fit equally well or better, heritability ranged from 0.89 to 0.93. This difference between the sexes was mainly due to the effect of the shared environmental component of variance, which appears to be more important among women than among men in our study populations. Our results indicate that, in general, there are only minor differences in the genetic architecture of height between affluent Caucasian populations, especially among men.     

Intraspecific diversity in the fungal speciesChaunopycnis alba: Implications for microbial screening programs

Intraspecific variation among 84 isolates of the anamorphic fungusChaunopycnis alba from 26 different geographical locations was analyzed by investigating optimal growth temperatures, differences in the production of secondary metabolites and presence or absence of the cyclosporin synthetase gene. The genetic diversity was assessed using random amplified polymorphic DNA (RAPD). Analysis of these data showed high genetic, metabolic and physiological diversity within this species. Isolates from the Antarctic represented the most homogeneous group withinC. alba and together with isolates from the Arctic these polar strains differed from alpine, temperate and tropical strains by low optimal growth temperatures and by low production of secondary metabolites. Isolates from tropical climes were characterized by high optimal growth temperatures and by the production of comparatively diverse metabolite spectra. Most of the isolates that were similar in the combination of their physiological and metabolic characters were also genetically related. Isolates from different geographical origins did not show many similarities, with the exception of the cyclosporin A-producing isolates, and large diversity could be observed even within a single habitat. This leads us to the suggestion that for pharmaceutical screening programs samples should be collected from a diversity of different geographical and climatic locations. For the selection of strains for screening the RAPD assay seems to be the most powerful tool. It reflected the highest intraspecific diversity and the results corresponded well with the other characteristics.     

An approach to integrated antibody production: Coupling of fluidized bed cultivation and fluidized bed adsorption

Continuous culture may be an efficient way of producing proteins which are susceptible to secondary processing in the course of a fermentation process. Short residence times in these systems support the production of correctly assembled proteins by avoiding substrate limitations and product inhibitions and also minimize the contact of sensitive bioproducts with degrading enzymes. Thus products of increased stability and integrity are obtained from continuous processes. The downstream process following continuous culture has to be adapted to the specific conditions of continuous fermentations, e.g. large liquid volumes and diluted process solutions. In this paper an approach is shown how a fluidized bed adsorption as first recovery operation may be coupled directly to a continuous production. Immobilized hybridoma cells are cultivated in porous glass microcarriers in a continuous fluidized bed process, the cell containing harvest is purified by fluidized bed adsorption using an agarose based cation exchange matrix. By this coupled mode of operation the large biomass containing harvest volume resulting from the continuous cultivation may be applied directly to a fluidized chromatographic matrix without prior clarification, leading to a particle free and initially purified product solution of reduced volume. In an experimental setup a bench-scale fluidized bed bioreactor of 25 ml carrier volume was coupled to a fluidized bed adsorption column operated with 300 ml of adsorbent. This configuration yielded up to 20 mg of monoclonal antibody per day in a cell free solution at fourfold concentration and fivefold purification. The process was run for more than three weeks with consistent product output.The help of H. Schmitz, A. Bader, J. Gätgens and M. Halfar during the experiments is gratefully acknowledged. This work was partially funded by the ministry of science and research of the Federal Republic of Germany within the project Stoffumwandlung mit Biokatalysatoren.     

Davydov Soliton Dynamics in Proteins: II. The General Case

We performed long time simulations using the |D₁> approximation for the solution of the Davydov Hamiltonian. In addition we computed expectation values of the relevant operators with the state (_D/J)|D₁> and the deviation |> from the exact solution over long times, namely 10 ns. We found that in the very long time scale the |D₁> ansatz is very close to an exact solution, showing expectation values of the relevant physical observables in the state (_D/J)|D₁> being about 5-6 orders of magnitudes larger than in the deviation state |>. In the intermediate time scale of the ps range such errors, as known from our previous work, are somewhat larger, but still more or less negligibly. Thus we also report results from an investigation of the very short time (in the range 0-0.4 ps) behaviour of the |D₁> state compared with that of an expansion of the exact solution in powers of time t. This expansion is reliable for about 0.12 ps for special cases as shown in the previous paper. However, the accuracy of the exactly known value of the norm and the expectation value of the Hamiltonian finally indicates up to what time a given expansion is valid, as also shown in the preceding paper. The comparison of the expectation values of the operators representing the relevant physical observables, formed with the third order wave function and with the corresponding results of |D₁> simulations has shown, that our expansion is valid up to a time of roughly 0.10-0.15 ps. Within this time the second and third order corrections turned out to be not very important. This is due to the fact that our first order state contains already some terms of the expansion, summed up to inifinite order. Further we found good agreement of the results obtained with our expansion and those from the corresponding |D₁> simulations within the time of about 0.10 ps. At later times, the factors with explicit powers of t in second and third order become dominant, making the expansion meaningless. Possibilities for the use of such expansions for larger times are described. Alltogether we have shown (together with previous work on medium times), that the |D₁> state, although of approximative nature, is very close to an exact solution of the Davydov model on time scales from some femtoseconds up to nanoseconds. Especially the very small time region is of importance, because in this time a possible soliton formation from the initial excitation would start.     

Intra-pancreatic release of bradykinin during the course experimental pancreatitis in rat

Kallikrein/Kininogn activation is an important pathophysiological event in acute pancreatitis, leading to microcirculatory changes within the gland. Hitherto, only indirect measurements of pancreatic bradykinin formation have been performed, monitoring the peptide in the circulation and in the peritoneal exudate. In the present study, intra-pancreatic bradykinin release was assessed using microdialysis during experimental acute pancreatitis in rat. In mild, oedematous pancreatitis, induced by caerulein hyperstimulation, the levels of bradykinin within the gland were not elevated compared with those of control rats. However, in necrotic pancreatitis, induced by retrograde injection of taurocholate into the pancreatic duct, significantly elevated levels of intraglandular bradykinin were seen. Several rats in this group died whilst in a state of circulatory shock.     

Syntheses ofγ-fluoro-α-amino acids

Summary Methods for the synthesis of racemic and optically active title compounds are presented. Key step of these four-step procedures is the alkylation with 1-bromo-2-fluoroalkanes of glycine-ester-derived imines in anhydrous medium using lithium diisopropylamide as a base at low temperature or phase transfer catalyzed alkylation with 50% NaOH and triethylbenzylammoniumchloride as the phase transfer catalyst, respectively. Subsequent three-step deprotection gave the free acids in 13–33% overall yield. Deracemization of-fluoro--aminobutyric acid methyl and ethyl esters with-chymotrypsin was shown to give the (–)-enantiomers of the esters and (+)--fluoro--aminobutyric acid in >98% ee, while from thetert-butylester the opposite stereochemical result was observed giving the (–)-acid with 88% ee. Optically active-fluoro--amino acids were synthesized alternatively by phase transfer catalysis with N-benzyl-cinchonium chloride or using an auxiliary-directed asymmetric alkylation of the imine derived from (R)-(+)-camphor or (R)-(+)-2-hydroxypinan-3-one. These processes gave different enantiomers of-fluoro--aminobutyric acid via a monomeric lithium enolate in the first or a dimeric lithium enolate in the second case, respectively. The enantiomeric excess can be improved by lithium/magnesium exchange.