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  • 1
    Electronic Resource
    Electronic Resource
    Distinct structural features of the .alpha. and .beta. subunits of nitrogenase molybdenum-iron protein of Clostridium pasteurianum: an analysis of amino acid sequences (1988)
    s.l. : American Chemical Society
    Biochemistry 27 (1988), S. 2800-2810 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00408a021
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  • 2
    Electronic Resource
    Electronic Resource
    The evolutionary pattern of aromatic amino acid biosynthesis and the emerging phylogeny of pseudomonad bacteria (1983)
    Springer
    Journal of molecular evolution 19 (1983), S. 272-282 
    Details
    ISSN: 1432-1432
    Keywords: Microbial phylogeny ; Evolution ; Aromatic biosynthesis ; Regulatory enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pseudomonad bacterial are a phylogenetically diverse assemblage of species named within contemporary genera that includePseudomonas, Xanthomonas andAlcaligenes. Thus far, five distinct rRNA homology groups (Groups I through V) have been established by oligonucleotide cataloging and by rRNA/DNA hybridization. A pattern of enzymic features of aromatic amino acid biosynthesis (enzymological patterning) is conserved at the level of rRNA homology, five distinct and unambiguous patterns therefore existing in correspondence with the rRNA homology groups. We sorted 87 pseudomonad strains into Groups (and Subgroups) by aromatic pathway patterning. The reliability of this methodology was tested in a blind study using coded cultures of diverse pseudomonad organisms provided by American Type Culture Collection. Fourteen of 14 correct assignments were made at the Group level (the level of rRNA homology), and 12 of 14 correct assignments were made at the finer-tuned Subgroup levels. Many strains of unknown rRNA-homology affiliation had been placed into tentative rRNA groupings based upon enzymological patterning. Positive confirmation of such strains as members of the predicted rRNA homology groups was demonstrated by DNA/rRNA hybridization in nearly every case. It seems clear that the combination of these molecular approaches will make it feasible to deduce the evolution of biochemical-pathway construction and regulation in parallel with the emerging phylogenies of microbes housing these pathways.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02099974
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  • 3
    Electronic Resource
    Electronic Resource
    The recent evolutionary origin of the phenylalanine-sensitive isozyme of 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase in the enteric lineage of bacteria (1987)
    Springer
    Journal of molecular evolution 25 (1987), S. 159-167 
    Details
    ISSN: 1432-1432
    Keywords: Metabolic evolution ; Aromatic biosynthesis ; Regulatory isozymes ; Enteric bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Evolutionary events that generated the three regulatory isozymes of 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase present in contemporary strains ofEscherichia coli have been proposed recently [Ahmad et al. (1986) J Bacteriol 165:146–154]. The phylogenetic subdivision of gram-negative prokaryotes studied (Superfamily B) includes enteric bacteria, anOceanospirillum cluster, pseudomonad Group I (e.g.,Pseudomonas aeruginosa), pseudomonad Group V (e.g.,Xanthomonas), and theAcinetobacter grouping. DAHP synthase-phe, a regulatory isozyme subject to allosteric control byl-phenylalanine, was the last member of the isozyme family to evolve. Thus, DAHP synthase-phe is absent throughout Superfamily B except within the enteric lineage. Bacteria that make up the enteric lineage (Escherichia, Klebsiella, Erwinia, Serratia, Proteus, Aeromonas, andAlteromonas) were examined in detail; DAHP synthasephe was present in each of these organisms. Therefore, the isozyme originated between the separation of the enteric andOceanospirillum lineages, prior to the divergence ofAlteromonas putrefaciens (44% homology withE. coli by DNA:rRNA hybridization) from the rest of the enteric lineage. DAHP synthase-tyr and DAHP synthase-trp were uniformly present within the enteric lineage, although it was often necessary to derepress DAHP synthase-trp by physiological manipulation in order to demonstrate its presence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02101758
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  • 4
    Electronic Resource
    Electronic Resource
    Phenylalanine hydroxylase and isozymes of 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase in relationship to the phylogenetic position of Pseudomonas acidovorans (Ps. sp. ATCC 11299a) (1985)
    Springer
    Archives of microbiology 141 (1985), S. 32-39 
    Details
    ISSN: 1432-072X
    Keywords: Phylogeny ; Pseudomonads ; Aromatic biosynthesis ; DAHP synthase ; Phenylalanine hydroxylase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The evolution of aromatic amino acid biosynthesis and its regulation is under study in a large assemblage of prokaryotes (Superfamily A) whose phylogenetic arrangement has been constructed on the criterion of oligonucleotide cataloging. One section of this Superfamily consists of a well defined (rRNA homology) cluster denoted as Group III pseudomonads. Pseudomonas acidovorans ATCC 11299a, a Group III member, was chosen for indepth studies of 3-deoxy-d-arabino-heptulosonate 7-phosphate (DAHP) synthase, the initial regulatory enzyme of aromatic biosynthesis. This strain is of particular interest for evolutionary studies of aromatic metabolism because it possesses phenylalanine hydroxylase, an enzyme whose physiological role and distribution among prokaryotes is largely unknown. Although P. acidovorans ATCC 11299a has been of uncertain identity, we now establish it unambiguously as a species of acidovorans by virtue of its 87% DNA homology with P. acidovorans ATCC 15668 (type strain). This result conformed with enzyme patterning studies which placed ATCC 11299a into pseudomonad Group IIIa, a subgroup containing the acidovorans species. Crude extracts of Group III pseudomonads had previously been shown to share, as a common group characteristic, sensitivity of DAHP synthase to feedback inhibition by either l-tyrosine or l-phenylalanine. Detailed studies with partially purified preparations from strain ATCC 11299a revealed the presence of two distinct regulatory isozymes, DAHP synthase-phe and DAHP synthase-tyr. DAHP synthase-tyr is tightly controlled by l-tyrosine with 50% inhibition of activity being achieved at 4.0 μM effector. DAHP synthase-phe is inhibited 50% by 40 μM l-phenylalanine and exhibits dramatic changes in levels of activity, as well as chromatographic elution patterns, in response to dithiothreitol. This two-isozyme pattern of DAHP synthase has not been described previously, although it may prove to be widespread.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446736
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  • 5
    Electronic Resource
    Electronic Resource
    Production of Biologically Active Human Protein C in the Milk of Transgenic Mice (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 665 (1992), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1992.tb42602.x
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  • 6
    Electronic Resource
    Electronic Resource
    The Porcine Mammary Gland as a Bioreactor for Complex Proteinsa (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 721 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb47394.x
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  • 7
    Electronic Resource
    Electronic Resource
    Hamiltonian approach to the magnetostatic equilibrium problem (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 2 (1995), S. 4499-4512 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The purpose of this paper is to investigate the classical scalar-pressure magnetostatic equilibrium problem for nonsymmetric configurations in the framework of a Hamiltonian approach. Requiring that the equilibrium admits locally a family of nested toroidal magnetic surfaces, the Hamiltonian equations describing the magnetic flux lines in such a subdomain are obtained for a general canonical curvilinear coordinate system. The properties of such a coordinate system are investigated and a representation of the magnetic field is obtained. Its basic feature is that the magnetic field must fulfill suitable periodicity constraints to be imposed on arbitrary rational magnetic surfaces for general nonsymmetric toroidal equilibria, i.e., it is quasisymmetric. Implications for the existence of magnetostatic equilibria are pointed out. In particular, it is proven that a generalized equilibrium equation exists for such quasisymmetric equilibria, which extends the Grad–Shafranov equation to fully three-dimensional configurations. As an application, a representation is obtained for generalized helically symmetric equilibrium, extending the definition given by Nührenberg and Zille [Phys. Lett. A 129, 113 (1988)]. Since the new representation overcomes the inconsistency exhibited by the previous representation near the magnetic axis, pointed out by Garren and Boozer [Phys. Fluids B 3, 2805, 2822 (1991)], it appears potentially useful to interpret the numerical findings of quasihelical equilibria obtained so far. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.871008
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  • 8
    Electronic Resource
    Electronic Resource
    Coordinate transform invariance (1996)
    Springer
    Foundations of physics 26 (1996), S. 1529-1557 
    Details
    ISSN: 1572-9516
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A four-dimensional operator is shown to contain the operator-generators for rotation, scale, reflections, and boosts. The hypothesis is advanced that a physical system changes under this operator by at most a complex phase factor due to invariance against the choice of menial frame. A canonical transform gives a simple relation between space-time and energy-momentum. The basic conserved quantity is a four-dimensional angular momentum and/or coupling constant. The differential of this function contains a second-order differential product which is constrained as a power series in the independent variable. The analysis explores the consequences of the model and shows its degree of correspondence to the standard models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02272369
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  • 9
    Electronic Resource
    Electronic Resource
    Altered IL-1 Expression and Compartmentalization in Monocytes from Patients with AIDS Stimulated with Mycobacterium avium Complex (1997)
    Springer
    Journal of clinical immunology 17 (1997), S. 387-395 
    Details
    ISSN: 1573-2592
    Keywords: Mycobacterium avium (MA) ; MA complex ; AIDS ; cytokines ; interleukin-1 (IL-1) ; IL-6 ; monocytes ; tumor necrosis factor-α
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The pathophysiologic basis for the exuberant intracellular growth of Mycobacterium avium complex (MAC) in AIDS patients is unclear but may relate to altered expression of modulatory cytokines. Interleukin (IL)-1, IL-6, and TNF-α expression by monocytes from AIDS patients and healthy subjects (HS) stimulated with isogeneic MAC strains (SmT, smooth-transparent, virulent; SmD, smooth-domed, avirulent) was examined. Spontaneous cytokine production was not observed in patients with AIDS. MAC strains induced less IL-1α and IL-1β release in AIDS patients than HS (P 〈 0.05). The ratio of cell-associated to supernatant IL-1α also was increased in AIDS patients (P = 0.03). IL-1β mRNA expression paralleled protein release in either group of subjects. In both HS and AIDS patients, stimulation with SmD induced more IL-1 and TNF-α release by monocytes compared to SmT. In AIDS patients, SmD also induced greater IL-6 release than SmT (P 〈 0.01). Alterations in monocyte expression and compartmentalization of the regulatory cytokines IL-1 and IL-6 may enhance bacterial replication and contribute to the patho-genesis of MAC infection in AIDS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1027316324382
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  • 10
    Electronic Resource
    Electronic Resource
    Use of the fast fourier transform for frequency analysis of the first heart sound in normal man (1976)
    Springer
    Medical & biological engineering & computing 14 (1976), S. 69-73 
    Details
    ISSN: 1741-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Description / Table of Contents: Sommaire On an analysé le premier son cardiaque enregistré au sommet cardiaque chez 29 jeunes hommes normaux, pour déterminer sa composition en fonction de la fréquence à l'aide de la technique de transformation rapide de Fourier. On remarqua que la spectre des fréquences contenait des pontes dans la zone des basses fréquences (10–50 Hz) et dans la zone des moyennes fréquences (50–140 Hz). La moyenne du spectre complet de l'étude présente une pointe a 30 Hz et une atténuation moyenne de 16 dB/octave au sommet du premier son cardiaque. Les pointes sont probablement apparentées aux propriétés élastiques de muscle cardiaque et les phénoménes occasionnant le premier son. Des informations diagnostiques importantes peuvent donc être dérivées de l'étude des fréquences des sons cardiaques. De telles études pourraient augmenter l'importance clinique de la phonocardiographie.
    Abstract: Zusammenfassung Der erste Herzton von 29 normalen jungen Männern an der Herzspitze wurde auf seinen Energiegehalt als Frequenzfunktion überprüft, wobei das Verfahren der schnellen Fourier-Transformierten verwendet wurde. Es wurde festgestellt, daß die Frequenzspektren Spitzen im niedrigen Frequenzbereich (10–50 Hz) und im mittleren Frequenzbereich (50–140 Hz) enthielten. Das mittlere Spekrtum der gesamten Untersuchung zeigt eine Spitze bei 30 Hz und eine durchschnittliche Dämpfung des ersten Herztons an der Herzspitze von 16 dB/Oktave. Die Spitzen beziehen sich wahrscheinlich auf die elastischen Eigenschaften des Herzmuskels und die dynamischen Vorgänge, die den ersten Ton verursachen. Aus Frequenzuntersuchungen der ersten Herztöne könnte man daher wichtige diagnostische Angaben erhalten. Solche Untersuchungen dürften die klinische Bedeutung der Phonokardiografie erhöhen.
    Notes: Abstract The first heart sound of 29 normal, young males, recorded at the apex of the heart, was analysed for the power content as a function of frequency using the technique of the fast Fourier transform. The frequency spectra were seen to contain peaks in the low-frequency range (10–50 Hz) and the medium-frequency range (50–140 Hz). The average spectrum of the entire study shows a peak at 30 Hz, and an average attenuation of the first heart sound at the apex, of 16 dB/octave. The peaks are probably related to the elastic properties of the heart muscles and the dynamic events causing the first sound. Therefore important diagnostic information might be obtained from frequency studies of heart sounds. Such studies should increase the clinical importance of phonocardiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02477093
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