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• 1970-1974  (47,024)
• 1973  (47,024)
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• 1
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New York, NY : Elsevier
Keywords: Biochemistry ; Enzymes
Notes: This is a series title, single volumes see link below.
ISSN: 1557-7988
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• 2
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Chicago : Year Book Medical Publ.
Associated volumes
Call number: QZ200Z:41
Keywords: Oncology / Congresses
Notes: Holdidngs of ZB: 1964-1988; Please search for single title in "Signatur" QZ200Z:41
ISSN: 0069-4800
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• 3
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Stuttgart : Enke
Call number: WB700:12(2)/1/Mag ; WB700:12(2)/2/Mag ; WB700:12(2)/3/Mag
Description / Table of Contents: 1. Abth. Die allgemeinen acuten Infectionskrankheiten.--2. Abth. Die chronischen Infections- und Intoxications-Krankheiten, parasitäre Krankheiten, infectiöse Wundkrankheiten und chronische Ernährungs-Anomalieen.--3. Abth. Die Organkrankheiten
Pages: 3 v.
Edition: 2. vollständig neue Bearbeitung.
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• 4
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Heidelberg : DKFZ
Call number: ZZ1980:9/Mag
Keywords: Deutsches Krebsforschungszentrum Heidelberg ; Oncology / Database ; Bibliometrics ; DKFZ-publications
Notes: Werke verschiedenner Autoren
Pages: various pagings
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• 5
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Call number: 09-MA:499/2 ; 09-Ma:499/3 ; 09-MA:499/4 ; 09-MA:499/5 ; 09-MA:499/6
Notes: Transl. of: Élements d'analyse. T. 2-6. Paris: Gauthier-Villars. 1969-1975
Pages: 5 v.
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• 6
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Oxford, UK : Blackwell Publishing Ltd
Birth 1 (1973), S. 0
ISSN: 1523-536X
Source: Blackwell Publishing Journal Backfiles 1879-2005
Topics: Medicine
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• 7
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Oxford, UK : Blackwell Publishing Ltd
Birth 1 (1973), S. 0
ISSN: 1523-536X
Source: Blackwell Publishing Journal Backfiles 1879-2005
Topics: Medicine
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• 8
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Oxford, UK : Blackwell Publishing Ltd
Birth 1 (1973), S. 0
ISSN: 1523-536X
Source: Blackwell Publishing Journal Backfiles 1879-2005
Topics: Medicine
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• 9
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Oxford, UK : Blackwell Publishing Ltd
Birth 1 (1973), S. 0
ISSN: 1523-536X
Source: Blackwell Publishing Journal Backfiles 1879-2005
Topics: Medicine
Notes: Recently I returned to teaching prenatal classes after an absence of 18 months. In my first class was a young girl who had been told that her baby was breech. She asked me if I would come with her and her husband in labor. I agreed, anticipating a chance to find out what was new at her teaching hospital and to help her, as well. A few weeks later I got her call, drove over and made my way up to her little labor room. For five minutes we talked. Then she panted quietly and rubbed her abdomen, her husband holding her other hand. At this point the door was propped open and a cabinet-sized machine was rolled into the room, pushed by a nurse. It stopped next to the bed, with a brief pause for the removal of the husband's chair to the corridor outside. The hand which had held the husband's was searched for a vein, and an intrevenous drip of glucose installed. The other arm was connected to a continuous blood pressure gauge. The abdomen was encircled with two belts and the electronic devices on the belts were squirted with jelly and planted firmly on the mother's abdomen, the belts then tightened securely. The monitor was turned on and out rolled a continuous strip of paper bearing the fetal heart rate tracing, the uterine contraction tracing, and the blood pressure tracing. The husband found a perch on a window sill across the room. For the next 7 hours a nurse or resident would come in at 30 minute intervals, study the tracing carefully, and tell the mother that all was well.In the next weeks I learned that nearly half of the women in my classes were being monitored, and the trend has increased in many areas. As a parent educator, I needed to know about fetal monitoring. Are the benefits so great as to justify such absolute domination of labor by machines? Is monitoring too complex to explain ahead of time to parents? I was disturbed by the lack of personal contact on the part of the staff, by the unseated husband and the lack of mobility of the mother. These worries led me to begin a search of the literature and correspondence with monitor manufacturers and several obstetricians who have pioneered in their development.
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• 10
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract An elementary proof of Araki's duality theorem for free fields is presented. The theorem says that for a certain class of regionsO in Minkowski space, the commutant of $$\mathfrak{A}$$ (O), the von Neumann algebra generated by all observables belonging to measurements withinO, is exactly $$\mathfrak{A}$$ (O′), whereO′ is the spacelike separated complement ofO.
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• 11
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The problem of the independence of the thermodynamic limit on the boundary conditions is considered in the framework of functional integration. For every domain and every boundary condition in a sufficiently large class a functional measure is constructed and the Feynman-Kac-like formula for the statistical operator written down. Making use of some volume-independent estimates for the Green function of the heat equation, the thermodynamic limit along convex domains for general boundary conditions is proved to exist and to be equal to that for Dirichlet conditions.
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• 12
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We investigate low temperature properties of an Ising ferromagnet when the nearest neighbour coupling constant is dominant. We show that all the translationally invariant equilibrium states are a superposition of only two extremal states.
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• 13
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract It is shown that any point of space-time has a neighbourhoodU such that theb-boundaryŪ ofU coincides withŪ/U.
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• 14
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We derive the kinematical magnification of tidal accelerations which occurs for test bodies in highly relativistic orbits preferentially aligned with respect to repeated principal null rays of algebraically special spacetimes. Some examples of astrophysical importance are discussed. A general expression for computing tidal accelerations in the Newman-Penrose formalism is given.
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• 15
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract It is shown that a torsion free linear connection is determined by a metric of given signature if and only if its holonomy group is a subgroup of the orthogonal group corresponding to the signature.
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• 16
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Solutions of the Cauchy problem associated with the Einstein field equations which satisfy general initial conditions are obtained under the assumptions that (1) the source of the gravitational field is a perfect fluid with pressure,p, equal to energy density,w, and (2) the space-time admits the three parameter group of motions of the Euclidean plane, that is, the space-time is plane symmetric. The results apply to the situation where the source of the gravitational field is a massless scalar field since such a source has the same stress-energy tensor as an irrotational fluid withp=w. The relation between characteristic coordinates and comoving ones is discussed and used to interpret a number of special solutions. A solution involving a shock wave is discussed.
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• 17
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract A shock wave in a self-gravitating fluid obeying the equation of state: pressure equal to energy density is shown to travel with the velocity of light in a space-time determined by the Einstein field equations. The jump conditions that must be satisfied by the hydrodynamic variables are derived and discussed as are those that must be satisfied by the metric tensor and its derivatives. The latter conditions are obtained by using a variational principle.
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• 18
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Springer
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract It was shown by Araki and Woods that the infinite free Bose gas can be described by states on the Weyl algebra; they conjectured a certain family of states parameterized by temperature and density to be the infinite volume limit of the Gibbs canonical states. We show here that this conjecture is correct. We show that the volume dependent canonical states are equicontinuous in the density by a detailed calculation and a combinatorial result that gives cancellations. This allows us to develop a method of Kac that connects the canonical states explicitly with the grand canonical states which are more easily controlled in the infinite volume limit.
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• 19
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Springer
Communications in mathematical physics 29 (1973), S. 105-111
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Two examples are presented: The first shows that a potentialV(x) can be in the limit circle case at ∞ even if the classical travel time to ∞ is infinite. The second shows thatV(x) can be in the limit point case at ∞ even though the classical travel time to infinity is finite. The first example illustrates the reflection of quantum waves at sharp steps. The second example illustrates the tunnel effect.
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• 20
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Communications in mathematical physics 29 (1973), S. 113-130
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The dynamical theory of a bidimensional model of hard squares with elastic collisions is presented. The time evolution is shown to exist on a large class of infinite configurations. Moreover, it is proved that any equilibrium state, that is any solution of the equilibrium equations, is concentrated on this set of allowed initial configurations and is invariant under the time evolution.
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• 21
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Communications in mathematical physics 29 (1973), S. 131-162
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract A method to solve Ising problems is developed giving all correlation functions. As an example the one-dimensional nearest and next-nearest neighbour models have been calculated explicitly.
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• 22
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Communications in mathematical physics 29 (1973), S. 163-175
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Given a classical spins system, namely, a set of spin sites of maximum spins inv-dimensional space along with a Hamiltonian defined on the possible spin configurations, a general method is described for constructing a large class of dual lattices of the same spin. The method utilizes the commutative group structure with which the configuration space is endowed.
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• 23
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The absence of strong interaction corrections to the axial anomaly in the σ model is proved in a cut-off independent way using Zimmermann's normal product algorithm.
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• 24
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Springer
Communications in mathematical physics 33 (1973), S. 119-128
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Some one-dimensional lattice systems with infinite range interactions define a Bernoulli shift.
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• 25
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Springer
Communications in mathematical physics 31 (1973), S. 265-277
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We use techniques which generalize the Lee-Yang circle theorem to investigate the distribution of zeroes of the partition function for various classes of classical lattice systems.
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• 26
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Communications in mathematical physics 31 (1973), S. 259-264
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract In four dimensions, it is possible for a scalar field to have a vacuum expectation value that would be forbidden if the vacuum were invariant under some continuous transformation group, even though this group is a symmetry group in the sense that the associated local currents are conserved. This is the Goldstone phenomenon, and Goldstone's theorem states that this phenomenon is always accompanied by the appearance of massless scalar bosons. The purpose of this note is to show that in two dimensions the Goldstone phenomenon can not occur; Goldstone's theorem does not end with two alternatives (either manifest symmetry or Goldstone bosons) but with only one (manifest symmetry).
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• 27
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Communications in mathematical physics 31 (1973), S. 279-290
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract For lattice invariant quasi free states on the Fermi lattice system the mean entropy is explicitly calculated; it is proved that it is a norm continuous functional on this set of states which is not weakly continuous.
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• 28
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Communications in mathematical physics 31 (1973), S. 291-294
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The entropy density of spin lattice systems is known to be a weak upper semi-continuous functional on the set of the lattice invariant states. (It is even weak discontinuous.) However we prove here that it is continuous with respect to the norm topology on those states.
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• 29
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Communications in mathematical physics 31 (1973), S. 295-316
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Guided by a diagonalized form of the classical field-energy we construct a time-dependent canonical pair of Schrödinger fields Φ t (x) and Π t (x) which diagonalizes the field-HamiltonianH t . These Schrödinger fields in general belong to inequivalent representations of the canonical commutation relations for differentt's. The Heisenberg field is constructed by solving the Heisenberg equation of motion and its time-evolution turns out to be governed by a unitary operator, i.e. the Heisenberg fields at different times are unitarily equivalent. Scattering theory (including eventual incoming and/or outgoing bound-states) is finally constructed.
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• 30
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Communications in mathematical physics 31 (1973), S. 317-325
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The concavity of two functions of a positive matrixA, Tr exp(B + logA) and TrA r KA p K* (whereB=B* andK are fixed matrices), recently proved by Lieb, can also be obtained by using the theory of Herglotz functions.
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• 31
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Communications in mathematical physics 31 (1973), S. 327-340
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We derive a classical integral representation for the partition function,Z Q , of a quantum spin system. With it we can obtain upper and lower bounds to the quantum free energy (or ground state energy) in terms of two classical free energies (or ground state energies). These bounds permit us to prove that when the spin angular momentumJ → ∞ (but after the thermodynamic limit) the quantum free energy (or ground state energy) is equal to the classical value. In normal cases, our inequality isZ C (J)≦Z Q (J)≦Z C (J+1).
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• 32
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract A gas of two Boson systems coexisting inR 3, and interacting only mutually, is analyzed. The interaction is quadratic, so that the dynamical problem may be solved completely and exactly. The initial state is taken to be the mutually uncorrelated Gibbs states:Φ β (1) ⊗Φ β (2) =Φ ψβ. We find the time evolved state, and its projections onto the separate species and the subvolumes. The principle consequences of this model are discussed. In particular we examine the possible occurrence of harmonic oscillations between the species.
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• 33
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We consider an Einstein spaceV of the Petrov type II or III admitting a group of motionsG of high order. First we calculate the composition law and topological structure ofG. ThenV (or its submanifolds of transitivity) is represented as the homogeneous spaceG/H ofG,H being a subgroup ofG, and the actionG onV and the topology ofV are determined. The topologies of the spacesV are as follows: ℝ4 (spaceT*2), ℝ4 of ℝ3 T1 (spaceT 2), ℝ4 (spaceT*3), ℝ3 (submanifolds of transitivity in spaceT 3). In two cases (spacesT 2 andT 3) we have obtained metrics free of singularities.
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• 34
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The set of allC 2 Lorentz metrics on a non-compact four-manifold is given the Whitney fineC 2 topology. It is shown that this provides the correct framework within which to discuss the global properties of spacetime manifolds in general, and the singularity theorems in particular. The main result is a theorem showing that the Robertson-Walker big bang (global infinite density singularity in the finite past) is stable under sufficiently small, but otherwise arbitrary, finiteC 2 perturbations of the metric tensor.
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• 35
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We define “normal-dominated” singularities of static solutions of the Einstein equations and show that a uniquely and invariantly defined structure can be assigned to these singularities. We find for the general solution that the dominant term of the Riemann tensor near the singularity is of Petrov Type N. Except for one special class of solutions, it seems that in general the shear of the null geodesics blows up at the same rate as their convergence near the singularity, in contradistinction to the “elementary singularity” of Newman and Posadas. We compute the structure for a variety of known static solutions as well as the stationary Kerr-Newman metrics.
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• 36
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract An elementary alternate proof of the semiboundedness of the locally correct HamiltonianH 0+ί:ø4(x):g(x)dx of the (ø4)2 quantum field theory model. The interaction operator is expressed as the sum of a positive operator and operators which are “tiny” relative to LN ε for any ɛ〉0, whereN is the number operator.
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• 37
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract The partition function of the Ising antiferromagnet is proved to have no zeroes in an annulus around the origin in the complexz-plane. The intersection of this annulus with the positive real axis belongs to the antiferromagnetic region. The free energy and the correlation functions are analytic in the annulus.
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• 38
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ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract For the Ising model with nearest neighbour interaction it is shown that the spin correlations 〈σ A σ B 〉 -〈σ A 〉〈σ B 〉decrease exponentially asd(A, B) → ∞ in a pure phase when the temperature is well belowT c. This is used to prove that the free energyF(β,h) is infinitely differentiable in β and has one sided derivatives inh of all orders forh=0. The bounds are also used to prove that the central limit theorem holds for several variables such as e.g. the total energy and the total magnetization of the system, the limit distribution being gaussian with variances determined by the second derivatives ofF(β,h).
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• 39
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Communications in mathematical physics 32 (1973), S. 107-118
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract First it is shown that each extremal equilibrium state is representable as limit of Gibbs states in finite volumes, and that an analogous statement holds for extremal invariant equilibrium states. Secondly we prove that for negative pair interactions only one equilibrium state exists which minimizes (resp. maximizes) the particle density, but that in general there are more than two extremal invariant equilibrium states with the same particle density. In this context, periodic interactions are studied.
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• 40
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Communications in mathematical physics 32 (1973), S. 119-146
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Parallel transport of line elements, surface elements etc. along geodesics and more general curves in a projectively connected manifold is investigated analytically and in terms of geometrical constructions. Projective curvature is characterized geometrically by a projective analogue of the geodesic deviation equation and by a geometrical construction. The results are interpreted physically as statements about free fall world lines in space-time.
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• 41
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Communications in mathematical physics 32 (1973), S. 147-152
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract For Einstein-Maxwell fields for which the Weyl spinor is of type {2, 2}, and the electromagnetic field spinor is of type {1, 1} with its principal null directions coaligned with those of the Weyl spinor, the integrability conditions for the existence of a certain valence two Killing tensor are shown to reduce to a simple criterion involving the ratio of the amplitude of the Weyl spinor to the amplitude of a certain test solution of the spin two zero restmass field equations. The charged Kerr solution provides an example of a spacetime for which the criterion is satisfied; the chargedC-metric provides an example for which it is not.
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• 42
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Communications in mathematical physics 32 (1973), S. 183-190
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We prove that the one-dimensional random fields with finite first moment are isomorphic to Bernoulli schemes.
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• 43
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Communications in mathematical physics 34 (1973), S. 131-134
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We show that a non discrete state of van Hove's Universal Receptacle in the fermion case is not unitarily equivalent to any quasi-free state.
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• 44
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Communications in mathematical physics 34 (1973), S. 135-148
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract It is shown that spherically symmetric collapse can lead to singularities which arenot hidden within “black holes”.
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• 45
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Communications in mathematical physics 34 (1973), S. 167-178
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Some inequalities for a general von Neumann algebra, which reduces to Golden-Thomspon and Peierls-Bogolubov inequalities when the von Neumann algebra has a trace, are proved.
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• 46
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Communications in mathematical physics 34 (1973), S. 149-166
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We study the action of the conformal algebra on interacting fields. On a certain set of states the algebra is integrated to projective representations ofSU(2,2). These representations are shown to be equivalent to the representations of the interpolated discrete series ofSU(2,2). Using this result we give a formula for the two-point Wightman function for arbitrary spin and dimension of the field. Finally we discuss the limit when the dimension tends to the canonical value.
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• 47
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Communications in mathematical physics 34 (1973), S. 179-192
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract We give a simple proof of Lorentz covariance for theP(φ)2 model without using the higher order estimates: For each Poincaré transformation {a, Λ} and each bounded regionB of Minkowski space there exists a unitary operatorU which correctly transforms the Heisenberg picture field operator:U φ(f)U*=φ(f (a,↔)),f ∈C 0 ∞ (B).
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• 48
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Communications in mathematical physics 34 (1973), S. 271-296
ISSN: 1432-0916
Source: Springer Online Journal Archives 1860-2000
Topics: Mathematics , Physics
Notes: Abstract Analyticity and uniqueness of correlation functions is investigated for a number of systems by application of Ruelle's theorem on zeros of Asano contracted polynomials to the partition function. To answer the question when the partition function of a system is the Asano contraction of those of subsystems the groups appearing in the low and high temperature expansions are employed.
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• 49
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Archives of microbiology 88 (1973), S. 11-24
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. A water soluble cytochrome c from Hemispora stellata has been obtained in a highly purified state by a series of steps involving (NH4)2SO4 precipitation and DEAE chromatography. 2. Absorption spectrum of the highly purified cytochrome c (550; H. stellata) in the reduced state shows maxima at 550, 520, 416, 357–362 nm and 310–320 nm. It has a symmetrical α band and ratios of αred./prot.ox and Soretred/αred. are 1 and 6.4 respectively. The purified cytochrome has a mesoheme prosthetic group, its molecular weight is about 17500, its isoelectric point is at pH higher than 8.6 and its É o is+0.28. 3. During DEAE chromatography of buffer extracts as well as of purified samples of cytochrome c (550; H. stellata) two bands were formed. Chromatographic experiments performed with pure samples of cytochrome c (550; H. stellata) and with horse heart cytochrome c from a commercial source suggest that this second band in the DEAE chromatographies is due to protein denaturation during the purification procedure. 4. Cytochrome c (550; H. stellata) is similar to cytochromes of microorganisms belonging to the families Cryptococcaceae and Moniliaceae and although it is also spectrophotometrically similar to cytochrome c from horse heart it has a highar molecular weight and midpoint redox potential.
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• 50
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Archives of microbiology 88 (1973), S. 49-60
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung Mit einer Ornithinmangelmutante von Neurospora crassa, arg-5, ota, aga, deren Sideraminbildung vollständig blockiert ist, wurde die Aufnahme von verschiedenen Sideraminen und von Eisencitrat untersucht. Ferrioxamin oxamin B sowie N-Acetyl-ferrioxamin B (Ferrioxamin D1) und N-Benzoyl-ferrioxamin B werden von Neurospora-Zellen nicht angereichert. Die transportkinetischen Daten zeigen, daß Neurospora crassa unter Eisenmangelbedingungen zwei voneinander differenzierbare Eisentransportsysteme ausbildet: das Coprogensystem und das Eisencitratsystem.
Notes: Summary With an ornithine-deficient mutant of Neurospora crassa, arg-5, ota, aga, whose sideramine production is completely blocked, the uptake of various sideramines and iron citrate was studied. Ferrioxamine B, as well as N-acetyl-ferrioxamine B (ferrioxamine D1) and N-benzoyl-ferrioxamine B were not accumulated by the cells of Neurospora. The kinetic data of transport indicate, that under iron-deficient conditions Neurospora evolves two distinguishable iron-transport systems: the coprogen system and the iron citrate system.
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Archives of microbiology 88 (1973), S. 71-76
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Growth of the fungus Penicillium charlesii G. Smith on glucose, minimal salts medium results in the appearance of α-d-mannopyranosidase activity capable of hydrolyzing p-nitrophenyl-α-d-mannopyranoside. No activity is found until depletion of the carbon source, after which the enzyme activity rapidly increases in the mycelium. Prolonged incubation of the culture results in the appearance of small amounts of α-mannosidase activity in the growth medium. The initial release of a mannose-containing polysaccharide into the medium precedes the appearance of α-mannosidase by several days.
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Archives of microbiology 88 (1973), S. 25-35
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung Ein zellfreier Extrakt aus Streptomyces rimosus katalysiert die Synthese von TDP-Mycarose aus TDP-d-Glucose und S-Adenosyl-l-methionin. Die Reaktion benötigt NADPH. Das Reaktionsprodukt enthält einen weiteren methylierten TDP-Zucker unbekannter Struktur. Die Reaktion verläuft über TDP-4-Keto-6-desoxy-d-glucose als Zwischenprodukt.
Notes: Summary A cell-free extract from mycelium of Streptomyces rimosus producing the antibiotic tylosin, catalyses the formation of TDP-mycarose from TDP-d-glucose and S-adenosyl-l-methionine. The reaction requires NADPH. The product contains a second methylated TDP-sugar with a presently unknown structure. TDP-4-Keto-6-deoxy-d-glucose is an intermediate in the reaction.
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Archives of microbiology 88 (1973), S. 1-10
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Geotrichum candidum grew filamentously in batch culture. Hyphal fragmentation occurred during growth; mycelial fragments in the early part of the stationary phase had a mean length of 300 to 400 μm. The dry weight, total hyphal length, number of hyphal tips and turbidity of the culture all increased exponentially at about the same specific growth rate. The results suggested, the existence of a functional unit of growth consisting of a hyphal tip associated with a constant mean length of hypha. The hyphal growth unit was defined as the ratio between the total hyphal length and number of hyphal tips in the culture; for G. candidum this unit was about 100 μm long and its length remained constant when the organism's specific growth rate was varied by changes in temperature, carbon source or the incorporation of cycloheximide in the medium.
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Archives of microbiology 88 (1973), S. 37-48
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung TDP-d-Glucose-oxidoreduktase wurde aus einem Tylosin produzierenden Stamm von Streptomyces rimosus 30 fach angereichert. Das Reaktionsprodukt wurde als TDP-4-Keto-6-desoxy-d-glucose identifiziert. Einige Eigenschaften des Enzyms wurden untersucht. Die Enzymaktivität steigt in Kulturen von S. rimosus in der stationären Phase etwa gleichzeitig mit der Tylosinkonzentration und dem TDP-Mycarose synthetisierenden System an; TDP-d-Glucose-oxidoreduktase ist daher als ein am Sekundärstoffwechsel beteiligtes Enzym anzusehen.
Notes: Summary TDP-d-glucose oxidoreductase was purified 30 fold from a tylosin producing strain of Streptomyces rimosus. The product of the enzymatic reaction is TDP-4-keto-6-deoxy-d-glucose as shown by spectral properties, chromatographic mobilities of the products obtained by chemical reduction of the nucleotide, and susceptibility of one of the reduction products to d-glucose oxidase. The enzyme has a pH-optimum of 7.2. The apparent Michaelis constant is 9.3 · 10-5 M for TDP-d-glucose. The enzyme is competetively inhibited by TMP (K i=5 · 10-3 M) and TDP (K i=6.5 · 10-5 M). Enzymatic activity is stimulated by NAD. TDP-d-glucose oxidoreductase activity increases during the stationary phase of S. rimosus together with tylosin and the TDP-mycarose synthesizing system; it is therefore regarded to be an enzyme with a function in the secondary metabolism of this organism.
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Archives of microbiology 88 (1973), S. 61-70
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Scanning electron microscopy and transmission electron microscopy (carbon replicas) confirm the existence of a deep longitudinal groove on one side of the pyriform body of the zoospores of Phytophthora palmivora. Upon encystment the cell rounds off but the groove may be temporarily retained as a depression on the cyst surface. The carbon replicas revealed significant differences in outer surface texture: the zoospore surface is finely granular whereas the outer surface of both young and mature cysts are distinctly microfibrillar with only occasional patches of amorphous material.
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Archives of microbiology 88 (1973), S. 193-204
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary The phycoerythrins from Rhodomonas sp. strain 3-C and Cryptomonas ovata var. palustris were purified and partially characterized. The phycoerythrin from Rhodomonas had a single visible absorption maximum at 542 nm with a shoulder at approximately 562 nm and is, therefore, representative of cryptophyte type I phycoerythrin. The phycoerythrin from C. ovata var. palustris had a single absorption maximum at 566 nm and is, therefore, representative of cryptophyte type III phycoerythrin. Calibrated gel filtration chromatography showed that both of these phycoerythrins have a native molecular weight of 30 800 daltons. Calibrated sodium dodecyl sulfate gel electrophoresis demonstrated that both pigments were composed of two subunits with apparent molecular weights of 17 700 and 11 000 daltons. On polyacrylamide gel electrofocusing both these phycoerythrins had an isoionic point of 4.90.
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Archives of microbiology 88 (1973), S. 181-192
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung Bei der Wirt-Parasit-Kombination Phaseolus vulgaris (cv. Favorit) und Uromyces phaseoli typica wird die Aktivität peroxydatischer Enzyme am dritten Tag nach Infektion elektronenmikroskopisch dargestellt. Die Aktivität in den Mitochondrien (möglicherweise eine Cytochromoxydase oder Cytochromperoxydase) ist in der infizierten Zelle erhöht. Die Peroxisomen (sie enthalten eine Katalase) bleiben in der infizierten Zelle unverändert. Im Pilz wird keine Katalaseaktivität gefunden. Die Schicht mit peroxydatischer Aktivität auf der Außenseite der Zellwand (Zellwandperoxydase) ist an der Berührungsstelle Hyphe—Wirtswand oft verdickt. An der Eintrittsstelle des Haustoriums in die Zelle wird Aktivität auf der Wand des Haustoriumhalses und auf den Cisternen des benachbarten ribosomenbesetzten endoplasmatischen Reticulums beobachtet. Manchmal findet man auch eine Schicht mit peroxydatischer Aktivität zwischen Scheide und Wand des Haustoriums.
Notes: Summary Peroxidase activity in Phaseolus vulgaris (cultivar Favorit), infected with Uromyces phaseoli typica, was studied with the help of an electronmicroscope. The plant material was prefixed three days after inoculation and 3,3-diaminobenzidine was used as a substrate to detect the enzyme activity. The mitochondrial membranes showed an enhanced enzyme activity (due to a cytochrome oxidase or possibly due to a cytochrome peroxidase) in the infected cell. There was no change in the structure and catalase activity of peroxisomes of the host. No catalase activity was detected in the fungus. A layer with evident peroxidase activity is seen outside the cell wall. This layer is sometimes thickened especially when it is in touch with intercellular hyphae. The penetration site of the haustorium has been intensively studied. Activity was observed in the neck region (from the penetration site of the haustorium to the neckband) in the zone between the host plasmalemma and the plasmalemma of the fungus. Some activity was also seen on the cisternae of the endoplasmic reticulum surrounding the neck. In a few preparations, activity was also found between sheath and wall of the haustorium.
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Archives of microbiology 88 (1973), S. 245-256
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Geotrichum lactis was grown in culture media with different carbon and nitrogen sources. Biotin is needed as a growth factor. During incubation in shake flasks mycelium and arthrospores are produced. Under certain conditions, such as low pH, there is a new form that we have called “yeast-like form”. This thick-walled form develops from mature arthrospores. The arthrospore and the yeastlike cells have walls with different chemical and structural composition, as observed in the electron microscope, and in their resistance to some lytic extracts.
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Archives of microbiology 88 (1973), S. 225-243
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung Unter natürlichen Bedingungen wurde die Massenentwicklung des Eisenbakteriums Gallionella ferruginea in einem fließenden System (Drainage) quantitativ bestimmt. Zugleich wurde die mathematische, Funktion für die Gesamtentwicklung erarbeitet. Zur Quantifizierung wurden Besiedlung und Bandbildung dieses sessilen Bakteriums auf Standort-exponierten Trägerflächen in Abhängigkeit von Zeit, Temperatur, Durchflußwassermenge und vom Material des Haftuntergrundes bestimmt. Die Untersuchungen führten zu folgenden Ergebnissen: 1. Die Längenzunahme der Gallionella-Bänder in den ersten 10 Std ihrer Entwicklung erfolgt linear mit einer konstanten Geschwindigkeit von 24,7±1,9% bis 29,0±1,6% μm/Std. 2. Die Gallionella-Besiedlungsdichte nimmt bei steigender Aufwuchsdauer in den ersten 10 Std der Entwicklung ebenfalls linear zu mit einer konstanten Besiedlungsgeschwindigkeit von 1,5±2,1% bis 4,5±0,4% Ind./mm2xStd. 3. Die Längenzunahme der Gallionella-Bänder hängt ab von der Temperatur des Standortwassers. Die Besiedlungsgeschwindigkeit ist abhängig von der Durchflußwassermenge (Strömungsgeschwindigkeit) und vom Material des Haftuntergrundes (Glas/Formvarfolie). 4. Die Gesamtentwicklung dieses Bakteriums als Funktion von Bandlängen-zunahme und Besiedlungsgeschwindigkeit nimmt in dem untersuchten fließenden System in den ersten 10 Std gleichmäßig beschleunigt zu. Die Entwicklung (V t) in diesem Zeitraum vollzieht sich nach der Gleichung $$V_{t(Gal)} = \frac{{b\bar v \times l\bar v}}{2} \times t^2$$ ( $$b_{\bar v}$$ =durchschnittliche Besiedlungsgeschwindigkeit; $$l_{\bar v}$$ =durchschnittliche Bandlängenzunahme; t≦10 Std). Ihre Zunahme erfolgt parabolisch.
Notes: Summary Mass development of the iron bacterium Gallionella ferruginea in a natural habitat (drainage) was determined quantitatively and described by equation. The quantification was done by determining density of Gallionella-settlement and stalk-elongation on artificial growing surfaces within the drainage (underwater “Aufwuchs” on glass slides) as dependent upon time, temperature quantity of water flow and substance of growth surface. The experiments led to the following results: 1. During the first 10 h of development Gallionella-stalks elongated linearly with a constant velocity between 24.7±1.9% and 29.0±1.6% μm/h. 2. Within the first 10 h of development the density of Gallionella-settlement also increased linearly at a rate of 1.5±2.1% to 4.5±0.4% Ind./mm2xh. 3. The elongation of the Gallionella-stalks is dependent upon the temperature of the drainage. The velocity of Gallionella-settlement is dependent upon the amount of water flow and the substance of the artificial surface (glass or form var membrane). 4. Mass growth of Gallionella within a drainage during the first 10 h of development increased with constant acceleration to attain the equation $$V_{t(Gal)} = \frac{{b\bar v \times l\bar v}}{2} \times t^2$$ ( $$b_{\bar v}$$ =average settlement velocity; $$l_{\bar v}$$ =average stalk elongation; t≦ 10h). The increase follows parabolically.
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Archives of microbiology 88 (1973), S. 285-298
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary A method for enumeration of viable numbers of Thiobacillus ferrooxidans using membrane filters on ferrous-iron agar is presented. Factors affecting colony production were the concentration and brand of agar, pH of the medium, and type of membrane filter. The results suggest that inhibition of T. ferrooxidans by agar is a result of the acid hydrolysis of agar, the main product of which is d-galactose. Colony development was suppressed by aged medium, by acid-hydrolysed agar and by 0.1% galactose. Sartorius and Millipore membrane filters were suitable for the experiments, whereas Oxoid MF-50 membranes virtually suppressed the production of colonies. The method was employed to follow growth of T. ferrooxidans in pH 1.3 medium. The viable cell numbers were correlated with 14CO2-fixation and ferrous iron oxidation. Generation time was 6 h 22 min with a yield of 2.2×1012 organisms/g atom Fe2+ oxidized. Growth of T. neapolitanus on thiosulphate medium was not affected by agar-type or membrane filters and yield of the organism was 1.5×1013 organisms/g molecule Na2S2O3 oxidized.
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Archives of microbiology 88 (1973), S. 319-330
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary In Nocardia opaca strain 1b the key enzymes of the Entner-Doudoroff pathway, 6-phosphogluconate dehydrase and 2-keto-3-deoxy-6-phosphogluconate aldolase, are inducible, while glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase are constitutively formed. In autotrophically grown cells the fructose diphosphate aldolase has six-fold specific activity compared to fructose- or gluconate-grown cells. Molecular hydrogen represses the adaptation to fructose, glucose, or gluconate and inhibits the utilization of glucose or fructose. Glucose-6-phosphate dehydrogenase has been purified 22fold. It utilizes either NADP of NAD as coenzyme; it requires magnesium ions for maximal activity. The dehydrogenation reaction is competitively inhibited by rather high concentrations (2–6 mM) of ATP, and in a similar fashion by phosphoenolpyruvate. Homotropic or heterotropic interactions between substrate molecules were not detected. The effect of ATP is relieved by equimolar concentrations of magnesium.
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Archives of microbiology 89 (1973), S. 317-320
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Effect of pesticides, i.e., Benzene Hexachloride, Lindane, Diazinon and Endrin that are often used in India was observed on nitrogen-fixing blue-green algae Cylindrospermum sp., Aulosira fertilissima Ghose and aerobically non-nitrogen-fixing blue-green alga Plectonema boryanum strain 594. These algae were sensitive for BHC in comparison to other pesticides. A. fertilissima and P. boryanum were more resistant than Cylindrospermum sp.
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Archives of microbiology 89 (1973), S. 305-315
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Catechol, gentisate, and compounds of the protocatechuic acid pathway are dissimilated in different sequences by P. testosteroni and P. putida. Results are discussed with respect to the velocity of enzyme reactions, the length of catabolic pathways, and the ATP-loss, caused by inhibition of the oxidative phosphorylation.
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Archives of microbiology 89 (1973), S. 291-304
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. Flagellar scales have been demonstrated for the first time in Synura echinulata, S. sphagnicola, S. spinosa, S. uvella and Mallomonopsis ouradion and on the smooth flagellum of S. petersenii in addition to those previously described for the long flagellum. In S. petersenii the scales are annular, approximately 100 nm in diameter with a 50 nm hole and in S. sphagnicola linear, 200–300 nm x 60 nm (observations on both flagella); in S. uvella they are semicircular, 60–70 nm x 20 nm, and in Mallomonopsis ouradion oval, 100–120 nm x 60 nm (observations on long flagellum only). Synura echinulata is unique among the species studied in having a mixture of clavate scales, 200 nm x 60 nm, and annular scales 100 nm in diameter on the long flagellum, though only the annular scales have been found on the smooth flagellum. Annular scales have been detected with difficulty on the long flagellum only of S. spinosa. 2. The scales are not arranged in a regular way and their attachment to the flagellar membrane is tenuous, the annular scales being attached by their edges, the elongate scales by one end and the semicircular scales in S. uvella by their convex side. 3. The scales are accumulated, and almost certainly also formed, in a large temporary vesicle similar to the flagellar scale reservoir in Pyramimonas in the Prasinophyceae. 4. This type of flagellar scale is unlike that in any other class of algae and, within the Chrysophyceae, appears to be restricted to genera in the Synuraceae.
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Archives of microbiology 89 (1973), S. 321-325
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Rates of oxygen evolution, 14CO2 uptake, and growth were measured in several species of algae and diatoms exposed to hydrostatic pressures up to 600 atm. All of the parameters measured decreased approximately linearly with increased pressure over the range tested. Oxygen evolution appears to be less sensitive to increased pressure than CO2 fixation or growth.
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Archives of microbiology 89 (1973), S. 355-362
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary A method is given for isolating nuclei from Euglena gracilis. The method yields 29% of the total DNA in the original culture in the final nuclear pellet. The protein: DNA mass ratio of the final pellet is 2.38.
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Archives of microbiology 89 (1973), S. 327-339
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. The efficiency of oxidative phosphorylation was estimated in intact “resting” cells of Proteus mirabilis, Escherichia coli B, Aerobacter aerogenes, Pseudomonas aeruginosa and Azotobacter vinelandii, measuring the change of ATP, ADP, AMP and NAD+ occurring on addition of limiting amounts of O2 to anaerobic cells of these bacteria. Also, in some cases O2-uptake was measured directly with a vibrating Pt-electrode. 2. Intact cells of P. mirabilis exhibited oxidative phosphorylation with a P/O-ratio of about 0.6–1.0. For A. aerogenes, P. aeruginosa and A. vinelandii a P/O-ratio of 0.30; 0.50 and 1.0 was found, respectively. 3. The reduction of NO3 - by anaerobic cells of P. mirabilis was accompanied by phosphorylation with a P/2e-(NO3 -)-ratio of about 0.37. 4. Changes in NAD+ were not representative of the amount of O2 consumed. So, methods in which the oxidation of NADH alone is taken as a measure for oxidative phosphorylation in bacteria do not give reliable P/2e--ratios. 5. It is concluded that P/O-ratios in intact “resting” bacterial cells are not as high as those for intact mitochondria from higher organisms and are also lower than P/O-ratios found for growing cells of bacteria.
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Archives of microbiology 89 (1973), S. 341-353
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. Rubredoxin was isolated from the facultative anaerobe Spirochaeta aurantia and from the obligate anaerobe Spirochaeta stenostrepta. The spirochetal rubredoxins contained one atom of iron per molecule and no inorganic sulfide. Their molecular weight (approximately 6000), spectral properties, and amino acid composition resembled those of rubredoxins obtained from anaerobic bacteria. A rubredoxin or a rubredoxin-like protein was present in the host-associated Treponema denticola. Rubredoxin was detected in extracts of both anaerobically- and aerobically-grown cells of S. aurantia. 2. An unstable ferredoxin was isolated from cell extracts of anaerobically-grown S. aurantia, but was not detected in aerobically-grown cells. The spectral characteristics and amino acid composition of this protein were similar to those of other bacterial ferredoxins. Four atoms of iron and four acid-labile sulfide residues were present per molecule. The molecular weight of S. aurantia ferredoxin was near 6000. S. aurantia ferredoxin preparations stimulated the formation of acetyl phosphate from pyruvate by diethylaminoethyl cellulose-treated extracts of Clostridium butyricum, whereas purified spirochetal rubredoxin did not.
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Archives of microbiology 92 (1973), S. 69-83
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary We have attempted to optimize conjugation and sporulation in Candida lipolytica, by studying the conditions of culture and growth. Copulation between compatible strains is a rare event, particularly in the case of auxotrophic mutants. However, diploids can be selected for on minimal medium provided parents are suitable auxotrophs. These diploids can multiply vegetatively for many generations. They can also be induced to sporulate at a very high frequency. Free ascospores were isolated by means of paraffin oil and segregations of markers could be studied. At first quite irregular, these segregations improved following a number of brother-sister matings. At the same time, the mean number of spores per ascus as well as spore germinability were considerably increased.
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Archives of microbiology 92 (1973), S. 63-68
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Description / Table of Contents: Zusammenfassung 1. Lebende Zellen virulenter A. tumefaciens B6 können den Tumorwuchsstoff Octopin und Arginin abbauen. 2. Diese Substanzen werden von hitze-getöteten Bakterien oder Kulturfiltrat nicht angegriffen. 3. Nach Zugabe von Octopin oder Arginin zu den Bakterien dauert es 2–3 Std, bis der Abbau beginnt. 4. Präinkubation der Bakterien mit Octopin bewirkt sofortigen Abbau frisch zugegebenen Octopins, Präinkubation mit Arginin beeinflußt den Octopinabbau nicht. Wohl aber bewirkt eine Präinkubation der Bakterien mit Arginin, daß bei Zugabe frischen Arginins sofort der Abbau beginnt. 5. Das Octopin abbauende Enzym ist nicht identisch mit Arginase. Käufliche Arginase greift das Octopin-Molekül nicht an. 6. Die Ergebnisse werden im Zusammenhang mit der Tumorbildung an Pflanzen diskutiert, die durch A. tumefaciens hervorgerufen wird.
Notes: Summary 1. Living cells of virulent Agrobacterium tumefaciens B6 can degrade the tumor growth factor octopine and also arginine. 2. These substances cannot be attacked by heat-killed bacteria or culture filtrate. 3. It takes 2–3 h after addition of octopine or arginine before degradation starts. 4. Preincubation of bacteria with octopine causes immediate degradation after addition of fresh octopine to the bacteria, preincubation with arginine does not influence the octopine degradation. But preincubation with arginine prepares the bacteria to degrade arginine rapidly. 5. The octopine degrading enzyme is not identical with arginase. Purchased arginase does not change the octopine molecule. 6. The results are discussed in respect to tumor formation by Agrobacterium tumefaciens in plants.
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Archives of microbiology 92 (1973), S. 91-103
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. A species of Aulacomonas was found in the wild feeding on Scenedesmus, and a light microscope investigation was made of movements, cell contents and the production of pseudopodia. 2. Electron microscope observations showed the biflagellate cells to be without scales and to have a complex flagella root system similar to that of Chlamydomonas. 3. Virus-like particles are descibed in and around the nucleus and compared with others previously reported in algae. 4. Possible relationships with other organisms are discussed.
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Archives of microbiology 92 (1973), S. 139-142
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary A phenylalanine-requiring strain of the unicellular blue-green bacterium Synechococcus cedrorum was isolated by means of penicillin enrichment following mutagenesis with nitrosoguanidine. Assays of pertinent enzymes indicated that prephenate dehydratase activity was absent in the mutant.
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Archives of microbiology 92 (1973), S. 123-138
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary 1. The isolation and chemical characterization of the lipopolysaccharides (O-antigens) of 12 strains of the gram-negative photosynthetic bacterium Rhodopseudomonas palustris is described. Lipopolysaccharides (LPS) were extractable with phenol/water, however, the bulk of the LPS of all strains remained in the phenol phase and only trace amounts were found in the aqueous layer. The LPS was also extractable by a phenol/chloroform/petroleum ether mixture (PCP-method), recommended for lipophilic glycolipids. Neither incubation of living bacteria with EDTA nor with NaCl liberated appreciable amounts of LPS-protein-lipid conjugates from the cells. 2. All strains investigated were found to have galactose, mannose, heptose, 2-keto-3-deoxyoctonate (KDO), glucosamine, 6-deoxy-glucosamine (quinovosamine) and a recently identified sugar, a 2,3-diamino-2,3-dideoxyhexose, as common LPS constituents. The presence of additional sugars allowed the classification of the strains into three distinct chemotypes. Chemotype I contains 4-O-methyl-D-xylose, and several non-identified amphoteric amino sugars. Chemotype II contains 4-O-methyl-D-xylose, 3-O-methyl-6-deoxy-D-talose, 6-deoxy-talose, xylose and again some unidentified amphoteric amino sugars, which were different from those of chemotype I. In chemotype III xylose, glucose, rhamnose, galactosamine and 6-O-methyl-glucosamine were identified. The main fatty acid in the high molecular weight material from the phenol phase of phenol/water extracts of all strains is β-hydroxymyristic acid. In addition in all strains β-hydroxypalmitic, palmitic and stearic acids were found. It has still to be proven that all these fatty acids are LPS constituents. 3. Like enteric LPS the LPS of R. palustris can be split by mild acid hydrolysis in a lipid portion (lipid A) and the degraded polysaccharide. But contrary to enteric lipid A, the lipid A of R. palustris does not contain glucosamine, but has the 2,3-diamino-hexose as the only amino sugar constituent. The possible occurrence of a common R-core and the question if repeating units exist in the O-specific chains of R. palustris LPS are discussed. 4. In two strains small amounts of additional LPS, which differ in their chemical composition from the respective LPS of the phenol phase, were isolated from the aqueous phase.
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Archives of microbiology 92 (1973), S. 179-187
ISSN: 1432-072X
Source: Springer Online Journal Archives 1860-2000
Topics: Biology
Notes: Summary Electron microscopy and enzymatic analysis show that the slime track of Dictyostelium discoideum represents a two-phase system with a fibrillar component, most likely cellulose, embedded in an amorphous, protein containing matrix. In contrast the slime from the sorus of the mature fruiting body is devoid of any fibrillar component. Thus, this organism produces two significantly different types of slime material.
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Archives of microbiology 92 (1973), S. 201-207