Showing papers by "University of Marburg published in 1978"

Carbon Monoxide Oxidation by Clostridium thermoaceticum and Clostridium formicoaceticum

Abstract: Cultures of Clostridium formicoaceticum and C. thermoaceticum growing on fructose and glucose, respectively, were shown to rapidly oxidize CO to CO(2). Rates up to 0.4 mumol min(-1) mg of wet cells(-1) were observed. Carbon monoxide oxidation by cell suspensions was found (i) to be dependent on pyruvate, (ii) to be inhibited by alkyl halides and arsenate, and (iii) to stimulate CO(2) reduction to acetate. Cell extracts catalyzed the oxidation of carbon monoxide with methyl viologen at specific rates up to 10 mumol min(-1) mg of protein(-1) (35 degrees C, pH 7.2). Nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate and ferredoxin from C. pasteurianum were ineffective as electron acceptors. The catalytic mechanism of carbon monoxide oxidation was "ping-pong," indicating that the enzyme catalyzing carbon monoxide oxidation can be present in an oxidized and a reduced form. The oxidized form was shown to react reversibly with cyanide, and the reduced form was shown to react reversibly with alkyl halides: cyanide inactivated the enzyme only in the absence of carbon monoxide, and alkyl halides inactivated it only in the presence of carbon monoxide. Extracts inactivated by alkyl halides were reactivated by photolysis. The findings are interpreted to indicate that carbon monoxide oxidation in the two bacteria is catalyzed by a corrinoid enzyme and that in vivo the reaction is coupled with the reduction of CO(2) to acetate. Cultures of C. acidi-urici and C. cylindrosporum growing on hypoxanthine were found not to oxidize CO, indicating that clostridia mediating a corrinoid-independent total synthesis of acetate from CO(2) do not possess a CO-oxidizing system.

Isolation and characterization of Desulfovibrio growing on hydrogen plus sulfate as the sole energy source

Abstract: Two sulfate reducing bacteria (Madison and Marburg strains) that grew on H2 plus sulfate in a mineral salts medium that contained acetate and CO2 as sole carbon source were isolated from diverse environments. During growth in this medium 4.2 mol of H2 were consumed per mol of sulfate reduced to sulfide. Acetate was required for biosynthetic purposes only. Approximately 70% of the cell carbon synthesized was derived from acetate and 30% from CO2. Acetate was not involved in dissimilatory sulfate reduction.

Growth yields and growth rates of Desulfovibrio vulgaris (Marburg) growing on hydrogen plus sulfate and hydrogen plus thiosulfate as the sole energy sources.

Abstract: Desulfovibrio vulgaris (Marburg) was grown on H2 plus sulfate and H2 plus thiosulfate as the sole energy sources and acetate plus CO2 as the sole carbon sources. Conditions are described under which the bacteria grew exponentially. Specific growth rates (μ) and molar growth yields (Y) at different pH were determined. μ and Y were found to be strongly dependent on the pH. Highest growth rates and molar growth yields were observed for growth on H2 plus sulfate at pH 6.5 (μ=0.15h-1; Y SO 4 2- =8.3g·mol-1) and for growth on H2 plus thiosulfate at pH 6.8 (μ=0.21h-1; Y S 2O 3 2 =16.9g·mol-1). The growth yields were found to increase with increasing growth rates: plots of 1/Y versus 1/μ were linear. Via extrapolation to infinite growth rates a Y SO4 2- /max of 12.2g·mol-1 and a YS2O 3 2- /max of 33.5g·mol-1 was obtained. The growth yield data are interpred to indicate that dissimilatory sulfate reduction to sulfide is associated with a net synthesis of 1 mol of ATP and that near to 3 mol of ATP are formed during dissimilatory sulfite reduction to sulfide.

Acetate assimilation and the synthesis of alanine, aspartate and glutamate in Methanobacterium thermoautotrophicum.

Abstract: Cultures of the autotrophic bacteriumMethanobacterium thermoautotrophicum were shown to assimilate acetate when grown on CO2 and H2 in the presence of acetate. At 1 mM acetate 10% of the cell carbon came from acetate, the rest from CO2. At higher concentrations the percentage increased to reach a maximum of 65%at acetate concentrations higher than 20 mM. The data suggest that acetate may be an important carbon source under physiological conditions. The incorporation of acetate into alanine, aspartate and glutamate was studied in more detail. The cells were grown on CO2 and H2 in the presence of 1 mM U-14C-acetate. The three amino acids were isolated from the labelled cells by a simplified procedure. Alanine, aspartate and glutamate were found to have the same specific radioactivity. Degradation studies showed that C1 of alanine C1 and C4 of aspartate, and C1 and C5 of glutamate were exclusively derived from CO2, whereas C2 and C3 alamine and aspartate, and C3 and C4 of glutamate were partially derived from acetate. These findings and the presence of pyruvate synthase, phosphoenolpyruvate carboxylase and α-ketoglutarate synthase inM. thermoautotrophicum indicate that CO2 is assimilated into the three amino acids via acetyl CoA carboxylation to pyruvate, phosphoenolpyruvate carboxylation to oxaloacetate, and succinyl CoA carboxylation to α-ketoglutarate.

Photoconduction in Polydiacetylene Multilayer Structures and Single Crystals. Evidence for Band‐to‐Band Excitation

Abstract: Steady state photoconduction action spectra for polydiacetylene multilayer structures and single crystals (TCDU) are reported. Interpretation is given in terms of a valence-to-conduction band transition which is buried under the vibronic sidebands of the dominant exciton transition. The associated absorption coefficient follows a (αb ħω) ˜ (ħω − Eg)2 law which indicates either an indirect transition or a direct transition between non-parabolic bands. The general validity of this relationship is supported by literature data for PTS, DCHD, and polyethylene. Gap energies are (2.5 ± 0.1) eV and (2.6 ± 0.1) eV for two different multilayer forms, (2.6 ± 0.1) eV for TCDU, (2.1 ± 0.1) eV for PTS, and (2.30 ± 0.05) eV for DCHD. The transition is three-dimensional indicating finite valence and conduction band dispersion perpendicular to the polymer chain direction. Fur Polydiazetylen-Multischichten und TCDU-Einkristalle werden Anregungsspektren fur stationare Photoleitung mitgeteilt. Zur Interpretation wird ein ubergang zwischen Valenz- und Leitungsband angenommen, der den vibronischen Seitenbanden des dominierenden Exzitonen-uberganges unterlagert ist. Der Absorptionskoeffizient gehorcht einem (αb ħω) ˜ (ħω − Eg)2-Gesetz, das entweder auf einen indirekten Ubergang oder auf einen direkten ubergang zwischen nichtparabolischen Bandern hindeutet. Literaturdaten fur PTS und DCHD sowie fur Polyathylen zeigen die generelle Gultigkeit dieser Beziehung. Die Bandabstande betragen (2,5 ± 0,1) eV und (2,6 ± 0,1) eV fur zwei verschiedene Multischicht-Strukturen, (2,6 ± 0,1) eV fur TCDU, (2,1 ± 0,1) eV fur PTS und (2,30 ± 0,05) eV fur DCHD. Der Ubergang besitzt drei-dimensionalen Charakter. Dies bedeutet, das Valenz- und Leitungsbander senkrecht zur Polymerkette eine endliche Dispersion besitzen mussen.

Purification and Properties of Reduced Ferredoxin: CO2 Oxidoreductase from Clostridium pasteurianum, a Molybdenum Iron‐Sulfur‐Protein

Abstract: Reduced ferredoxin: CO2 oxidoreductase from Clostridium pasteurianum, a ferredoxin-dependent soluble formate dehydrogenase, was purified 3000-fold with an overall yield ranging between 10 and 20%. The enzyme was at least 85% pure as judged by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and by the molybdenum content. The enrichment was performed in the presence of 10 mM azide, a competitive inhibitor of the enzyme, and under strictly anaerobic conditions (E∼–400 mV) in order to protect the CO2 reductase from rapid inactivation. The purification procedure included a heat step, a precipitation by polyethyleneimine and by ammonium sulfate, a sedimentation by ultracentrifugation, and a chromatography on DEAE-cellulose in 39% ammonium sulfate. The highly purified CO2 reductase contained 7.2 nmol of molybdenum, 170 nmol of non-heme iron and 150 nmol of acid-labile sulfur per mg of protein. The spectrum of the enzyme was typical of an iron-sulfur protein. Selenium, tungsten, flavins or heme could not be detected in significant amounts. The enzyme consisted of a number of aggregated forms with molecular weights near 700000, 460000, and 240000 which could be partially dissociated in the presence of 1% Triton X-100 into an enzymatically active species of molecular weight 118000. Treatment with sodium dodecl sulfate led to a dissociation of the enzyme into two enzymatically inactive polypeptide chains of molecular weights near 34000 and 86000. The purified enzyme will catalyze the following reactions at the same relative rates as the cell-free extracts: (a) the reduction of CO2 to formate with reduced ferredoxin, (b) the oxidation of formate to CO2 with oxidized ferredoxin, (c) an isotopic exchange between 14CO2 and formate in the absence of ferredoxin, and (d) the reduction of methyl viologen with formate. It is concluded that CO2 reductase from C. pasteurianum is a molybdenum iron-sulfur protein containing 1 mol of molybdenum, and 24 mol of non-heme iron and acid-labile sulfur per mol enzyme of molecular weight 118000.

Tolerance to shift of sleep, as related to the individual's circadian phase position.

Abstract: The differential adaptation of ‘morning’ and ‘evening’ types to changes in sleep schedules was investigated in two studies. The first was carried out on six female subjects, classified as morning or evening types on the basis of their rhythms of body temperature, and on their answers to a morningness-eveningness questionnaire. Bed times on single nights were varied between 2100h and 0300 h. On each night measurements were taken of latency of sleep onset and of sleep duration. Body temperature, heart rate and respiratory rate were also recorded, as was self-estimated vigilance during the day following the experimental sleep. Evidence of sleep deficiency after late bed limes was found in the morning but not in the evening types; the latter, however, had longer sleep latencies after early bed times than the morning types. In the second study eight male subjects underwent the same basic experimental treatment, but in this case sleep was monitored for three consecutive nights with a given bed time, in order to...

Biliprotein Assembly in the Disc-Shaped Phycobilisomes of Rhodella violacea

Abstract: Heterogeneous complexes with a molecular weight of about 790000 containing B-phycoerythrin (Bangiales phycoerythrin) and C-phycocyanin (Cyanophyceae phycocyanin) in a molar pigment ratio of 2:1 were isolated from purified, dissociated phycobilisomes. Electron microscopical investigations revealed structures of three discs aggregated face to face with an apparent distance of 1.5 nm between each disc. Two discs may represent phycoerythrin and one phycocyanin. The complexes are structurally identical with tripartite units of the phycobilisome periphery. Fluorescence data confirmed the integrity of isolated tripartite units. Excitation at 546 nm gives a fluorescence maximum at 644 nm, indicating intermolecular transfer of excitation energy from phycoerythrin to phycocyanin. Comparative subunit analyses and spectral data suggested that no allophycocyanin is present. Cross-linking experiments gave evidence for a polar arrangement of phycocyanin within the complex. This pigment itself is an aggregate of two smaller molecules each having a molecular weight of about 140000. Tripartite units contain all the phycoerythrin and phycocyanin of the phycobilisome. On this basis, a phycobilisome model is proposed which combines the aspects of biliprotein distribution, energy transfer and fine structure.

Evidence for an incomplete reductive carboxylic acid cycle in Methanobacterium thermoautotrophicum.

Abstract: The involvement of reactions of the tricarboxylic acid cycle in autotrophic CO2 fixation in Methanobacterium thermoautotrophicum was investigated. The incorporation of succinate into glutamate (=α-ketoglutarate), aspartate (=oxaloacetate) and alanine (=pyruvate) was studied. The organism was grown on H2 plus CO2 at pH 6.5 in the presence of 1 mM [U-14C-]succinate. Significant amounts of the dicarboxylic acid were incorporated into cellular material under these conditions. Alanine, aspartate, and glutamate were isolated and their specific radioactivities were determined. Only glutamate was found to be labelled. Degradation of glutamate revealed that C-1 of glutamate was derived from CO2 and C-2-C-5 from succinate indicating that in M. thermoautotrophicum α-ketoglutarate is synthesized via reductive carboxylation of succinyl CoA. The finding that succinate was not incorporated into alanine and aspartate excludes that oxaloacetate and pyruvate are synthesized from α-ketoglutarate via isocitrate or citrate. This is taken as evidence that a complete reductive carboxylic acid cycle is not involved here in autotrophic CO2 fixation.

Compatibility and long‐term stability of glass–ceramic implants

Abstract: The biocompatible and bioactive glass–ceramic material Ceravital, which has been developed, can be adapted to the physiological conditions of the organism by apropriately monitoring its chemical composition. The material exhibits a remarkable long-term stability in in vitro solubility tests and when used as implants in animal experiments.

Carcinoembryonic antigen and ferritin in patients with lung cancer before and during therapy

Abstract: Carcinoembryonic antigen (CEA) levels were determined in 114 patients with confirmed lung cancer at the time of diagnosis using the CEA Ire-Sorin radioimmunoassay. Elevated CEA values were found in 47%. Most of the patients with high CEA levels had clinically detectable metastases. Ferritin was detectable by the Laurell-electrophoresis in the serum of 58 out of 81 (72%) of the patients with confirmed lung cancer at the time of diagnosis. Ferritin levels were significantly higher in patients with metastases. Serial measurements of CEA and ferritin during radio- and chemotherapy showed that the assay may be useful to evaluate the effects of therapy. Because of some false negative results both CEA and ferritin determinations should be used only in context with other clinical and laboratory findings.

Dreikernige Sandwichkomplexe mit Dialkylphosphonat-Brückenliganden: Synthese, NMR-, IR- und Raman-spektroskopische Untersuchungen

Abstract: Es wird uber die Synthese des Halbsandwichkomplexes [C5H5Co{P(O)(OR)2}2{P(OH)(OR)2}] (4) aus [C5H5Co{P(OR)2O}3BF]BF4 (3) berichtet. 4 ist ein neuartiger O3-Tripodligand, der mit den zweiwertigen Metall-Ionen M = Mg, Ca, Sr, Ba, Pb, Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg zu dreikernigen Verbindungen der Zusammensetzung [{(C5H5)Co[P(O)(OR)2]3}2M] (5a–m) reagiert. In den sandwich-artigen Komplexen 5 bilden die Dialkylphosphonatliganden Brucken der Art Co(PO)3M(OP)3Co zwischen den drei Metallzentren. Die 1H-NMR-Spektren werden diskutiert. Im IR-Spektrum beobachtet man als Folge der nicht regularen Oktaederkoordination beim CuII-Komplex 5j und bei der Quecksilberverbindung 5m eine Aufspaltung der VP = O und δP = O-Banden. An Hand der IR-Spektren wird gezeigt, das die Jahn-Teller-Verzerrung des CuII-Komplexes 5j unter einem Druck von 35 kbar aufgehoben werden kann. Trinuclear Sandwich Compounds Containing Dialkylphosphonate as Bridging Ligands: Synthesis, NMR-, IR-, and Raman Studies The solvolysis of [C5H5Co{P(OR)2O}3BF]BF4 (3) leads to the half-sandwich complex [C5H5Co{P(O)(OR)2}2{P(OH)(OR)2}] (4). 4 is a novel O3-tripod ligand which reacts with the bivalent metalions M = Mg, Ca, Sr, Ba, Pb, Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg to give the trinuclear compounds [{(C5H5)Co[P(O)(OR)2]2}2M] (5a–m). In these sandwich like complexes the dialkylphosphonate ligands are forming bridges of the type Co(PO)3M(OP)3Co between the three metal centers. The 1H NMR spectra are discussed. Due to a non-regular octahedral coordination of the central ion M = Cu and Hg the vP = O and δP = O bands in the IR spectra of 5j and 5m are split. It is shown by means of the IR spectra that the Jahn-Teller distorted octahedral coordination of CuII in 5j is changed to a regular one under the influence of high pressure (35 kbar).

Plant Microbody Proteins

Abstract: 1 Isocitrate lyase from cotyledons of cucumber seedlings (Cucumis sativus) has been purified 100-fold. Two methods of preparing the soluble glyoxylate cycle enzyme are described: an elaborated method which used crude extracts of cucumber cotyledons, and another procedure which started with purified glyoxysomes from 4-day-old cotyledons and included a separation of glyoxysomal matrix enzymes by zonal centrifugation. The product behaved as a single species when tested by (a) polyacrylamide gel electrophoresis in the presence of dodecyl sulfate, (b) zonal centrifugation, and (c) double immunodiffusion against rabbit antibody to isocitrate lyase. 2 Isocitrate lyase of cucumber glyoxysomes exhibited a molecular weight of 255 000 and was composed of four apparently identical subunits of Mr 64 000. An isoelectric point of 5.9 was determined. 3 It was shown that isocitrate lyase is a glycoprotein, (a) by Schiff stain on polyacrylamide gels, (b) by periodate oxidation of the enzyme, subsequent reduction with NaB[3H]4 and electrophoretic analysis of the labelled glycoprotein, and (c) by incorporation of [3H]glucosamine in vivo into a protein which could be precipitated with antibodies to isocitrate lyase and revealed a 64 000-Mr band upon electrophresis.

Biosynthetic pathways to 6-aminolevulinic acid induced by blue light in the pigment mutant c-2a‘ of scenedesmus obliquus†

Abstract: The X-ray induced mutant C-2A′ of Scenedesmus obliquus grows heterotrophically but forms only traces of chlorophyll in the dark. Upon illumination, δ-aminolevulinic acid (ALA) is synthesized and chlorophyll is formed These processes are blue light dependent and cease immediately when the cells are transferred back into darkness. Addition of levulinic acid (LA) inhibits the light-dependent formation of chlorophyll and causes accumulation of ALA by competitive inhibition of the ALA dehydratase (EC. 4.2.1.24). By feeding specifically labelled 14C precursors to the pigment mutant, inhibiting the ALA dehydratase with LA, accumulating, extracting and analyzing the ALA, two pathways leading towards ALA could be established: glycine and succinyl CoA can be condensed to ALA and the 5 carbon skeleton of glutamate can completely be incorporated into ALA via a second pathway. The glycine-succinyl CoA pathway dominates over the glutamate pathway, but both lead to chlorophyll formation.

Memory effects in the linewidth and line shape near the laser threshold

Abstract: A mode-coupling approximation and a continued-fraction representation are used to calculate the memory kernels of the dynamical field and photon-number correlation functions near a single-mode laser's threshold. The resulting linewidths of field and intensity fluctuations versus pumping are in good agreement with Risken's numerical calculations as well as with empirical linewidth data. In addition details of the line shape are also reported. The deviations from a Lorentzian are appreciable in the proper threshold region.

Magnetic properties of ferromagnetic γ‐Fe films on Cu (111)

Abstract: Epitaxial f.c.c. γ-Fe-films on Cu (111) with a well-defined structure are measured magnetometrically. Layer-grown as well as island-grown films prepared with a film thickness between 3 and about 85 A, are found to be ferromagnetic with a magnetic moment of (0.58 ± 0.13) μB/atom. The temperature dependence of the anisotropy field differs fundamentally for layer- and islandgrown films. The existence of ferromagnetic γ-Fe-films, which seems to be controversal to the antiferromagnetism of γ-Fe-precipitates, can be explained by the epitaxial expansion of the lattice parameter and will be discussed in terms of different concepts of the magnetic order in γ-Fe. Epitaktische k.f.z.-γ-Fe-Filme auf Cu (111) mit wohldefinierter Struktur werden magnetometrisch vermessen. Im untersuchten Schichtdickenbereich von 3 bis ca. 85 A sind diese Filme ferromagnetisch mit einem magnetischen Moment von (0,58 ± 0,13) μB/Atom, sowohl fur flachenhafte als auch fur Inselschichten. Die Anisotropiefelder dagegen zeigen fur flachenhafte und Inselscher γ-Fe-Filme im Gegensatz zu den antiferromagnetischen γ-Fe-Ausscheidungen wird auf die epitaktisch gedehnte Gitterkonstante zuruckgefuhrt und im Rahmen verschiedener Modelle der magnetischen Ordnung des γ-Fe diskutiert.

The Optical Absorption Spectrum of Fluid Sulfur up to Supercritical Conditions

Abstract: Optical absorption spectra in the range 0.5–4.9 eV (250 to 2000 nm) are reported for fluid sulfur up to 1100°C and at pressures up to supercritical pressures. An absorption band at 360 nm at 145°C is attributed to a few percent cyclo-S6 (c-S6) in the predominantly cyclo-S8 (c-S8) liquid. No anomaly in the rate of red shift of the absorption edge is observed at the polymerization temperature (160°C). Above this temperature an absorption band due to diradical chains is observed at low energy (∼1.4 eV). Investigation of the density dependence of the spectra of the dense fluid results from overlapping bands due to c-S8, S3, and S4. Es werden optische Absorptionsspektren im Bereich von 0.5–4.9 eV (250–2000 nm) fur fluiden Schwefel bis zu 1100°C und bis zu uberkritischen Drucken berichtet. Eine bei 145°C bei 360 nm beobachtete Bande wird dem cyclo-S6 (c-S6), von dem angenommen wird, das einige Prozent neben dem vorherrschenden cyclo-S8(c-S8) vorhanden sind, zugeordnet. Es wird keine Anomalie der Rotverschiebung der Absorptionskante bei der Polymerisationstemperatur (160°C) beobachtet. Oberhalb dieser Temperatur wird eine den Biradikalketten zugeordnete neue Bande bei niedriger Energie (∼1.4 eV) beobachtet. Die Dichteabhangigkeit der Spektren des Schwefels bei uberkritischen Temperaturen zeigt, das die Absorptionskante der dichten Flussigkeit aus den uberlappenden Banden von c-S8, S3 und S4 entsteht.

Multiple functions of thioredoxins.

Abstract: Reduced thioredoxins from microbial and plant cells, both of cytoplasmic or chloroplast origin, are interchangeable in stimulating such diverse enzyme activities as ribonucleoside diphosphate reductase (E. coli), PAPS sulfotransferase (Synechococcus), and fructose-1,6-bis-phosphatase (from spinach) in vitro. It is suggested that reduced thioredoxins are unspecific, multifunctional cellular proteins while in contrast the oxidized froms require specific enzymes for their reduction.

Two Biosynthetic Pathways to δ-Aminolevulinic Acid in a Pigment Mutant of the Green Alga, Scenedesmus obliquus

Abstract: Pigment mutant C-2A′ of the unicellular green alga Scenedesmus obliquus develops only traces of chlorophyll and has no detectable amount of δ-aminolevulinic acid (ALA) when grown in the dark. In light it develops ALA and in the presence of levulinic acid (LA), a competitive inhibitor of ALA dehydratase, it accumulates 0.18 mmoles of ALA per 10 microliters of packed cell volume per 12 hours. This amount could be increased up to 15 times by feeding precursors and cofactors. Incubation with [U- 14 C]glutamate, [1- 14 C]glutamate, and [2- 14 C]glycine yielded significantly labeled ALA, whereas [1- 14 C]glycine did not label the ALA specifically. Thus, two pathways using either glycine/succinyl-coenzyme A or incorporating the whole C-5-skeleton of glutamate into ALA are present in this alga. The efficiency of the glycine/succinyl-coenzyme A pathway seems to be three times higher than that of the glutamate pathway. Incubation with [5- 14 C]2-ketoglutarate, which can serve both pathways as a precursor, resulted in radioactivity of ALA as high as the sum of both labeling with [1- 14 C]glutamate and [2- 14 C]glycine. Since the newly synthesized chlorophyll was radioactive regardless of labeled substrate employed, both pathways culminate in chlorophyll formation.

Electron spin resonance in amorphous germanium and silicon

Abstract: The contributions to the spin resonance absorption lines observed in amorphous silicon and germanium are discussed in terms of the different relaxation processes. It is shown that besides a g-value distribution, hyperfine interaction contributes significantly. Dipolar and anisotropic exchange interactions are shown to be of minor importance except at the highest spin densities. The temperature-dependent increase in linewidth is explained by a modulation of the spin-orbit interaction owing to the motion of the carriers. A semiclassical model is used to show that the distribution of spin-flip times given by a sequence of consecutive hops in the framework of variable-range hopping can lead to the observed changes in linewidth and lineshape. Some exchange interaction is required to narrow the lines and to transfer the hopping-induced spin-flip rate to the spins far below the Fermi level. An anti-ferromagnetic exchange of the order of 1 K as reported recently, however does not seem likely in the light...

Isolation and Characterization of Secretory Actin · DNAase I Complex from Rat Pancreatic Juice

Abstract: DNAase I isolated from rat pancreatic juice was always found in association with a protein of molecular weight 43 000. This association leads to inhibition of the isolated rat pancreatic DNAase I activity by 66%. The molecular weight of the complex was found to be 74 000 by gel filtration indicating a 1 : 1 molar association of both proteins. Since the protein of molecular weight 43 000 has a number of properties similar to skeletal muscle actin such as filament formation, nucleotide binding, inhibition of the rat pancreatic DNAase I activity and comigration with skeletal muscle actin on polyacrylamide gels in the presence of dodecylsulfate, it is concluded that DNAase I is bound to actin in rat pancreatic juice in a 1 : 1 complex. It is demonstrated that a protein fraction from bile is able to activate the DNAase I enzymatic activity of the rat secretory actin . DNAase I complex.

X-inactivation pattern in three cases of X/autosome translocation.

Abstract: We describe an X/15 translocation which was balanced in a phenotypically normal mother [46,X,t(X;15)(p22;q15)] and unbalanced in her phenotypically abnormal daughter [46,X,der(X),t(X;15)(p22;q15)mat]. A third case involves a balanced X/21 translocation in a girl with a multiple congenital anomaly-retardation syndrome [46,X,t(X;21)(p11;p11?)]. 5-BrdU acridine orange banding on lymphocytes revealed late replication of the normal X chromosome in the mother and of the normal or abnormal X chromosome in the two other cases. Our findings are only partially consistent with previous observations. All X-inactivation patterns can be explained by random inactivation and subsequent selection against specific cell lines. Furthermore, the findings in our patient with X/21 translocation support the hypothesis of the existence of one inactivation center on Xq.