Showing papers by "University of Göttingen published in 1976"
TL;DR: The soluble hydrogenase from Alcaligenes eutrophus H 16 was purified 68-fold with a yield of 20% and a final specific activity (NAD reduction) of about 54 mumol H2 oxidized/min per mg protein, and was shown to be homogenous by polyacrylamide gel electrophoresis.
336 citations
TL;DR: In this paper, it was shown that the defect energy required for the formation of a defect pair greatly exceeds the thermal energy, kBT, in a typical ionic crystal, and the same is true of the ionic conductivity.
230 citations
TL;DR: In this paper, it was shown that the presence of Fe(II)-containing solutions in recent sediments is necessary for the formation of the bidimensional orientation of SiO 4 tetrahedrons, leading to clay-mineral formation.
156 citations
TL;DR: This method was used in 4 children with tunnel-like subaortic stenosis, 3 of whom had had unsuccessful previous surgical attempts, and two patients died postoperatively, one from advanced myocardial damage and progressive failure and the other from cerebral ischemia caused by insufficient retrograde perfusion through an aortic coarctation that was not repaired earlier.
128 citations
112 citations
TL;DR: Tumour biopsies from Burkitt lymphoma patients, as well as human nasopharyngeal carcinoma cells growing in athymic nude mice, contain Epstein–Barr virus DNA as covalently closed circular DNA.
Abstract: Tumour biopsies from Burkitt lymphoma patients, as well as human nasopharyngeal carcinoma cells growing in athymic nude mice, contain Epstein–Barr virus DNA as covalently closed circular DNA. In addition, integrated viral DNA sequences seem to be present.
110 citations
TL;DR: Evidence is presented that somatostatin is released from isolated rat pancreatic islets and that insulin and somatstatin release are interrelated.
105 citations
TL;DR: d-Ribulose 1,5-diphosphate carboxylase has been purified from autotrophically grown cells of the facultative chemolithotrophic hydrogen bacterium Alcaligenes eutrophus and was homogeneous by the criteria of polyacrylamide gel electrophoresis.
Abstract: d-Ribulose 1,5-diphosphate carboxylase has been purified from autotrophically grown cells of the facultative chemolithotrophic hydrogen bacteriumAlcaligenes eutrophus. The enzyme was homogeneous by the criteria of polyacrylamide gel electrophoresis. The molecular weight of the enzyme was 505000 determined by gel filtration and sucrose density gradient centrifugation, and a sedimentation coefficient of 18.2 S was obtained. It was demonstrated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis that the enzyme consists of two types of subunits of molecular weight 52000 and 13000.
102 citations
TL;DR: In this paper, EEG data were collected from 16 young women during a spontaneous menstrual cycle (s.c.w. group) and from 16 women taking combined oral contraceptives (o.c.) group.
100 citations
TL;DR: The dorsal openings in the myelin sheath of the median giant fiber of the earthworm (Lumbricus terrestris L.) have been studied with electronmicroscopical and electrophysiological methods and show a characteristic differentiation into large desmosomal contacts.
Abstract: The dorsal openings in the myelin sheath of the median giant fiber (MGF) of the earthworm (Lumbricus terrestris L.) have been studied with electronmicroscopical and electrophysiological methods. The fine structure of the dorsal nodes (DN) resembles in many aspects the Ranvier nodes in vertebrate and crustacean nerve fibers. The nodal membrane directly faces the extracellular collagenous capsule of the ventral cord and displays a conspicuous electrondense undercoat. The myelin sheath of the paranode shows a characteristic differentiation into large desmosomal contracts. Recordings of the transmembrane and longitudinal surface currents along the dorsal side of the MGF during spike propagation support the view that an active inward current is restricted there to the DN. The inward current density in the DN reaches outstandingly high values similar to those measured in vertebrate nodes of Ranvier. The nodal activity can be blocked by application of tetrodotoxin and local anaesthetics. Local electrical stimulation of only one DN may suffice to elicit propagated actions potentials up and down the MGF. It is concluded that the dorsal nodes of the median giant fiber of the earthworm are highly specialized excitable structures mediating saltatory impulse conduction in these fibers.
94 citations
TL;DR: In this article, the diffusive motion of silver ions in σ-AgI at 250°C has been studied by quasielastic cold neutron scattering, and the model closely fits the data.
01 Dec 1976
TL;DR: 3-Chlorobenzoate grown cells of Pseudomonas strain B 13 readily co-oxidize 3-methylbenzoate yielding 82% (+)-2,5-dihydro-4-methyl- and 9% (+-2,4-diverse-2- methyl-5-oxo-furan- 2-acetic acid (compounds I and II, X=CH3).
Abstract: 3-Chlorobenzoate grown cells ofPseudomonas strain B 13 readily co-oxidize 3-methylbenzoate yielding 82% (+)-2,5-dihydro-4-methyl- and 9% (+)-2,5-dihydro-2-methyl-5-oxo-furan-2-acetic acid (compounds I and II, X=CH3). The concentration of the products in the culture fluid exceed 11 g per liter without affecting the activity of the cells. The products were formed in 89% and 93% yield when 3- or 4-methylcatechol is cometabolized correspondingly. The lactonization of methyl- and halomuconic acids is discussed with regard to the mechanism of halide elimination during utilization of chlorosubstituted aromatic compounds.
TL;DR: It is demonstrated that the duodenum is not necessary for GIP release and that pancreatic and jejunal gastrin are without clinical significance.
Abstract: The response of serum immunoreactive gastric inhibitory polypeptide (IR-GIP), gastrin (IRG) and insulin (IRI) to a mixed standard meal was measured in 15 controls, 6 patients with coeliac disease, 26 patients with chronic pancreatitis and 6 patients with chronic pancreatitis and partial duodenopancreatectomy (Whipple's procedure). Serum levels of IR-GIP, IRG and IRI were significantly reduced in patients with coeliac disease. The serum glucose increase was significantly smaller only during the first hour after the meal. Since small intestinal GIP- and G-cells are situated mainly in the glands of duodenal and jejunal mucosa their absolute number is not significantly reduced in coeliac disease. It is suggested that the release of IR-GIP and duodenal IRG is influenced by the rate of absorption of nutrients. In patients with chronic pancreatitis the IR-GIP release is significantly greater than in controls, the IRG release normal and the IRI response delayed. After Whipple's procedure the IR-GIP response is increased significantly while the IRG secretion is abolished. This demonstrates that the duodenum is not necessary for GIP release and that pancreatic and jejunal gastrin are without clinical significance.
TL;DR: Since this wall autolysine is a factor produced by the cells themselves at a particular stage in their life cycle it represents a non-foreign agent in contrast to all other enzymic methods previously employed for protoplast isolation.
Abstract: Prior to fusion, gametes ofChlamydomonas reinhardii discard their cell walls. This naturally occuring phenomenon has provided the basis for a method of protoplast isolation from both gametes and vegetative cells within the genusChlamydomonas. When synchronized cultures of compatibleChlamydomonas gametes are mixed it is possible, after removal of the cells, to obtain a solution having a high cell wall lytic activity. That vegetative and gamete cells after treatment with this “gamete-autolysine” are indeed protoplasts has been proved by various light and electron microscopical methods. The species specifity of this autolysine, its difference to the previously described “sporangialautolysine” (Schlosser 1966) and furthermore its use in the large scale production of protoplasts is also described. Since this wall autolysine is a factor produced by the cells themselves at a particular stage in their life cycle it represents a non-foreign agent in contrast to all other enzymic methods previously employed for protoplast isolation.
TL;DR: In this paper, a systematic study of the exponent of convergence δ(G) of a Fuchsian group was carried out, and it was shown that in various senses δ (G) is a continuous function of G. In view of the incompleteness of our knowledge about convergence, considerable attention was paid to illustrative examples.
Abstract: This paper continues the systematic study of the exponent of convergence δ(G) of a Fuchsian groupG begun byA. F. Beardon. The object is to show that in various senses δ(G) is a continuous function ofG. In view of the incompleteness of our knowledge about δ(G) considerable attention is paid to illustrative examples.
TL;DR: When Rhodopseudomonas gelatinosa was grown on acetate aerobically in the dark both enzymes of the glyoxylate bypass, isocitrate lyase and malate synthase, could be detected, however, under anaerobic conditions in the light only isocite lyase, but not malates synthase could be found.
Abstract: When Rhodopseudomonas gelatinosa was grown on acetate aerobically in the dark both enzymes of the glyoxylate bypass, isocitrate lyase and malate synthase, could be detected. However, under anaerobic conditions in the light only isocitrate lyase, but not malate synthase, could be found.
TL;DR: In this paper, a method is presented which is suitable for the analysis of the individual glucosinolates (GSLs) in seeds and leaves of rapeseed (Brassica napus and B. rapa).
Abstract: A method is presented which is suitable for the analysis of the individual glucosinolates (GSLs) in seeds and leaves of rapeseed (Brassica napus and B. campestris). By ion exchange at pH 7 with K2SO4 as eluans it is possible to investigate also plant tissues with a high content of sucrose such as roots of turnip (B. rapa var. rapa). The same technique is recommended for the analysis of plant material with a low content of GSLs (<10 μmole/g dry matter). The use of Al-capsules as reaction vessels offer an elegant and inexpensive way for the conversion of GSLs to their corresponding trimethylsilyl derivatives. With methylsilylhexafluorobutyramide (MSHFBA) as donor of the silyl group deterioration of FID-detectors can be lowered to a minimum degree.
Quantitative Gaschromatographie von Glucosinolaten im Mikromasstab
Es wird eine Methode vorgestellt, die fur die Analyse der einzelnen Glucosinolate (GSL) in Samen und Blattern von Raps und Rubsen (Brassica napus und B. campestris) geeignet ist. Mittels Ionenaustausch bei pH 7 mit K2SO4 als Eluans ist es moglich, auch Pflanzengewebe mit einem hohen Gehalt an Saccharose wie Rubenkorper der weisen Rube (B. rapa var. rapa) zu untersuchen. Die gleiche Technik wird fur die Analyse von Pflanzenmaterial mit einem niedrigen Gehalt an GSLn (<10 μMol/g Trockensubstanz) empfohlen. Die Verwendung von Al-Kapseln als Reaktionsgefase ist ein eleganter und billiger Weg, um GSLe in ihre entsprechenden Trimethylsilylderivate zu uberfuhren. Mit Methylsilylhexafluorbutyramid (MSHFBA) als Silylgruppendonator wird die Verschmutzung von FID-Detektoren weitgehend herabgesetzt.
TL;DR: In this paper, the reaction rates of CH 3 + and CD 3 + were studied in shoch waves at 1200-1500 K and densities of 2 × 10 −6 −2 ×10 −4 mol cm −3 using UV absorption near 216 nm.
TL;DR: In this article, the partitioning of Sr between calcite, dolomite and liquids is essentially independent of temperature between 150° and 350° C. This ratio is due to the fact that calcite has twice as many Ca-sites for Sr-substitution as DOLOMITE.
Abstract: The partitioning of Sr between calcite, dolomite and liquids is essentially independent of temperature between 150° and 350° C. The partition coefficients corrected for number of cation sites are b
calc=0.096 and b
dol= 0.048 for 1 mol cations/6 mol H2O liquid. Upon dilution the partition coefficients increase, but their ratio stays constant at about 2∶1. This ratio is due to the fact that calcite has twice as many Ca-sites for Sr-substitution as dolomite. The 2∶1 relationship is also observed in natural calcite and dolomite which have undergone diagenesis. The temperature independence of partitioning is caused by the relatively small thermal expansion of calcite and dolomite. Thermal expansion between 25° and 400° C was found to follow the equations V
calc=7.0·10−4
T(°C)+36.95 and V
dol=6.9·10−4
T(°C)+32.24, V: cm3/mol. Therefore calcite and dolomite cannot serve as a temperature indicator. To have an ideal geothermometer a mineral pair with high and low thermal expansion is required. Literature date demonstrate that wurtzite, sphalerite, and galena are such minerals.
TL;DR: With the exception of the H2 oxidase all oxidase activities in lysozyme membranes are sensitive to carbonylcyanide m-chlorophenylhydrazone (20-100% stimulation of oxygen uptake), which is believed to represent an oxygenated form of the reduced cytochrome.
01 Jul 1976
TL;DR: In this article, the thermal decomposition of acetaldehyde and of acetone was investigated behind reflected shock waves in the temperature range 1350 K to 1650 K, using argon as a diluent.
Abstract: Die thermischen Zerfallsreaktionen von CH3CHO und CH3COCH3 in Argon als Tragergas wurden zwischen 1350 K und 1650 K hinter reflektierten Stoswellen untersucht. Die Gesamtdichten hinter der reflektierten Stoswelle lagen zwischen 3 · 10−3 und 9 · 10−6 mol/cm3. Die Zerfallsreaktionen verliefen bei den angewandten Reaktionsbedingungen nach erster Ordnung in CH3CHO bzw. CH3COCH3. Die Extrapolation der Meswerte zu hohen Drucken fur die Reaktionen
fuhrt zu den Arrheniusausdrucken
Die Druckabhangigkeit der Geschwindigkeitskonstanten sowie die Zerfallsmechanismen werden diskutiert.
The thermal decomposition of acetaldehyde and of acetone was investigated behind reflected shock waves in the temperature range 1350 K to 1650 K, using argon as a diluent. Total densities varied from 3 · 10−3 mol/cm3 to 9 · 10−6 mol/cm3. Under the conditions used in these experiments the decompositions were first order in CH3CHO- and in CH3COCH3-concentrations. For the reaction
the Arrhenius expressions in the high pressure limit
could be obtained from the extrapolation of the rate data. Pressure dependence of the rate constants as well as reaction mechanisms are discussed.
TL;DR: The application of 3-(3,4-Dichlorphenyl)-1,1-dimethylharnstoff (DCMU) can be used as a new method for culturing Chlorella-free Paramecium bursaria and the Bedeutung dieser stoffwechselphysiologischen Beziehung für die Symbiosepartner wird diskutiert.
Abstract: Symbiotic Chlorellae have been isolated from Paramecium bursaria Ehrbg. and cultivated under conditions of nitrogen deficiency. Reinfection of Chlorella-free Paramecium bursaria with these nitrogen-deficient algae resulted in a complete regeneration and multiplication of the algae within the host cells. The endosymbiotic algal cells of the Paramecium bursaria-symbiosis can be supplied by their host with nitrogen. The inhibition of photosynthesis by 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) leads in green Paramecium bursaria to a breakdown of the symbiotic steady state-system resulting in a loss of algal cells. Obviously the endosymbiotic algae cannot be fed heterotrophically by their host to such an extent that a stable symbiosis is maintained. The application of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU) can be used as a new method for culturing Chlorella-free Paramecium bursaria.
TL;DR: For conserved local currents ∂µjµ(x)=0 in quantum field theory, it has been shown that an R-dependence of αR(x0) with respect to a fixed α(x 0) leads to nice properties as discussed by the authors.
Abstract: For conserved local currents ∂µjµ(x)=0 in quantum field theory it is shown that anR-dependence of αR(x0) inj0(fR(x)·αR(x0)) leads to nicer properties than a fixed α(x0). The behaviour of\(\mathop {\lim }\limits_{R \to \infty } \left\| {j_0 (f_R (x) \cdot \alpha _R (x_0 )\Omega } \right\|\) ‖j0(fR(x)·αR(x0)Ω‖ is discussed under this aspect.
TL;DR: In adult rats the tibial nerve was stimulated at the ankle and the evoked EMG of the foot muscles was recorded and a low threshold reflex discharge was elicited that was subsequently depressed by stronger stimuli eliciting the direct (M) wave.
TL;DR: The histogenesis of papillary and nonpapillary transitional cell carcinomas were studied morphologically and autoradiographically in 177 female Wistar rats after oral application of N-butyl-N-(4-hydroxybutyl)-nitrosamine with varying exposure and induction times.
Abstract: The histogenesis of papillary and nonpapillary transitional cell carcinomas were studied morphologically and autoradiographically in 177 female Wistar rats after oral application of N-butyl-N-(4-hydroxybutyl)-nitrosamine with varying exposure and induction times By far the largest proportion of carcinomas developed by a malignant transformation of preexisting papillomas or their precursors, the papillary hyperplasias The transition into a focally malignant growth did not take place abruptly, but occurred stepwise through different successive stages of transformation, each having its own distinct morphological character The first stage consisted of a focal, sharpely defined cellular atypia In a further stage carcinomata in situ developed out of the atypical foci and progressed finally in a last stage of transformation into a circumscript infiltrative growth The successive development of each stage occurred independent of any further carcinogen application after transformation was initiated at the molecular level The number of papillomas with transformation stages increased with a lengthening of the exposure and induction time 744% of all the registered papillomas had been transformed Consequently papillomas must be considered potentially highly malignant The 3H-TdR index was 42 times higher in atypical urothelial areas (76%) and 75 times higher in carcinomata in situ (143%) than in the surrounding papillomatous structures which appeared light microscopically benign The latter demonstrated a rather constant 3H-TdR index, whether they bordered on atypical foci (18%) or carcinomata in situ (19%) The length of exposure and induction time exercised no significant influence on the degree of proliferative activity
TL;DR: The results provide a satisfactory explanation of the high correlations between the static and gross dynamic behaviour of deefferented primary muscle spindle endings of the EDL previously reported from the authors' laboratory.
Abstract: A detailed analysis of the complex dynamic response of 8 deefferented primary muscle spindle endings to ramp stretches of the extensor digitorum longus muscle (EDL) was made in anaesthetized cats. The analysis was based on Lennerstand's linear muscle spindle model, in which the dynamic peak, i.e. the peak frequency at the end of the dynamic phase of a ramp stretch, is assumed to consist of three components: a position response, a slow velocity response, and a quick velocity response. The components of the dynamic peaks analysed were fairly well correlated with the static behaviour of the primary muscle spindle endings, the latter, in turn, being regarded as an indicator of the spindle's location in the non-homogeneous extrafusal muscle. The results thus provide a satisfactory explanation of the high correlations between the static and gross dynamic behaviour of deefferented primary muscle spindle endings of the EDL previously reported from our laboratory.
01 Jan 1976
TL;DR: In dem einleitenden Abschnitt sollen folgende Themen behandelt werden: ==================¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯ The gesetzmasigen Beziehungen zwischen der Dynamik und der Energetik des Herzens;============¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯€€£€€€ €€£££€£
Abstract: In dem einleitenden Abschnitt sollen folgende Themen behandelt werden:
Die gesetzmasigen Beziehungen zwischen der Dynamik und der Energetik des Herzens;
der dynamische und energetische Arbeitsbereich des intakten Herzens;
die theoretischen Moglichkeiten der Regulation der Kontraktilitat, mittels des elementaren molekularen Myosin-Querbrucken-Mechanismus.
TL;DR: A flash photolysis system has been used to study the rate of reaction (1), OH + CH4 CH3 + H2O, using time-resolved resonance absorption to monitor OH.
Abstract: A flash photolysis system has been used to study the rate of reaction (1), OH + CH4 CH3 + H2O, using time-resolved resonance absorption to monitor OH. The temperature was varied between 300 and 900°K. It is found that the Arrhenius plot of k1 is strongly curved and k1 (T) can best be represented by the expression
The apparent Arrhenius activation energy changes from 15±1 kJ/mole at 300°K to 32±2 kJ/mole at 1000°K. On either side of our temperature range, both absolute rates and their temperature dependence are in good agreement with the results from most previous investigations.