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  • 1
    Call number: S040:51
    Keywords: Microbiology
    Pages: xxii, 536 p. : ill.
    ISBN: 978-3-8274-1798-5
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    S040:51 departmental collection or stack – please contact the library
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  • 2
    Unknown
    Amsterdam : Elsevier/Academic Press
    Keywords: Microbiology / English ; eBooks
    Pages: 6 v. : ill., ports.
    Edition: 3rd ed.
    ISBN: 9780123739391
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Advances in Space Research 14 (1994), S. 297-305 
    ISSN: 0273-1177
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    BBA - Enzymological Subjects 76 (1963), S. 275-279 
    ISSN: 0926-6569
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Molecular microbiology 14 (1994), S. 0 
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: A mutant Escherichia coli that transforms minichromosomes with high efficiency in the absence of Dam methylation has been Isolated and the mutation mapped to 16.25 min on the E. coli map. The mutant strain containing seqA2 is defective for growth in rich medium but not in minimal medium. A similar mutation In this gene, named seqA1, has also been isolated.Here we show that the product of the seqA gene, SeqA, normally acts as an inhibitor of chromosomal initiation. In the seqA2-containing mutant, the frequency of initiation increases by a factor of three. Introduction of the wild-type seqA gene on a low-copy plasmid suppresses the cold sensitivity of a dnaAcos mutant known to overinitiate at temperatures below 39°C. In addition, the seqA2 mutation is a suppressor of several dnaA (Ts) alleles.The seqA2 mutant overinitiates replication from oriC and displays the asynchronous initiation phenotype. Also the seqA2 mutant has an elevated level of DnaA protein (twofold).The introduction of minichromosomes or a low-copy-number plasmid carrying five DnaA-boxes from the oriC region increases the growth rate of the seqA2 mutant in rich medium to the wild-type level, reduces overinitiation but does not restore synchrony. We propose that the role of SeqA is to limit the activity level of the E. coli regulator of chromosome initiation, DnaA.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In the present study, the possible role of genetic polymorphism of three drug-metabolizing enzymes, debrisoquine/sparteine hydroxylase (CYP2D6), glutathione S-transferase μ (GSTM1), and N-acetyltransferase (NAT2), as a putative genetic component of human longevity, was explored. A total of 817 DNA samples from a centenarian and a control (20–70 years) population was subjected to PCR-coupled RFLP methods. Subjects were genotyped for the CYP2D6*3 (A2637 deletion) and CYP2D6*4 (G1934A transition) alleles, for four mutations of NAT2 [namely, NAT2*5A (C481T), NAT2*6A (G590A), NAT2*7A (G857A), and NAT2*14A (G191A)], and for the presence or absence of GSTM1 gene deletion. No significant difference was found at these three loci between centenarian and control subjects with respect to allelic variant frequencies, genotype distributions or predicted phenotypes deduced from genotype combinations. By comparing the distribution of combined genotypes for the polymorphisms tested at the CYP2D6, NAT2, and GSTM1 loci, none of the predicted phenotypes concerning debrisoquine hydroxylase extensive-metabolizer or poor-metabolizer phenotypes, slow or fast N-acetylation capacities, and active or defective glutathione S-transferase, could be correlated with human longevity, alone or in combination.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Longevity varies between and within species. The existence of species-specific limit to human life-span and its partial heritability indicate the existence of genetic factors that influence the ageing process. Insight into the nature of these genetic factors is provided by evolutionary studies, notably the disposable soma theory, which suggests a central role of energy metabolism in determining life-span. Energy is important in two ways. First, the disposable soma theory indicates that the optimum energy investment in cell maintenance and repair processes will be tuned through natural selection to provide adequate, but not excessive, protection against random molecular damages (e.g. to DNA, proteins). All that is required is that the organism remains in a sound condition through its natural expectation of life in the wild environment, where accidents are the predominant cause of mortality. Secondly, energy is implicated because of the intrinsic vulnerability of mitochondria to damage that may interfere with the normal supply of energy to the cell via the oxidative phosphorylation pathways. Oxidative phosphorylation produces ATP, and as a by-product also produces highly reactive oxygen radicals that can damage many cell structures, including the mitochondria themselves. Several lines of evidence link, on the one hand, oxidative damage to cell ageing, and on the other hand, energy-dependent antioxidant defences to the preservation of cellular homeostasis, and hence, longevity. Models of cellular ageing in vitro allow direct investigation of mechanisms, such as oxidative damage, that contribute to limiting human life-span. The genetic substratum of inter-individual differences in longevity may be unraveled by a two-pronged reverse genetics approach: sibling pair analysis applied to nonagenarian and centenarian siblings, combined with association studies of centenarians, may lead to the identification of genetic influences upon human longevity. These studies have become practicable thanks to recent progress in human genome mapping, especially to the development of microsatellite markers and the integration of genetic and physical maps.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusions I. L'inoculation sur l'œuf embryonné (voie intra amniotique) du broyat ganglionnaire provenant de sujets atteints de la maladie de Hodgkin, détermine 4–6 jours après l'inoculation, la mort d'un petit nombre d'embryons ainsi que des lésions hémorragiques tégumentaires chez la plupart des embryons inoculés. II. Sur les empreintes effectuées à partir du tégument embryonnaire lésé, on peut mettre en évidence des corpuscules similaires aux pararickettsies. III. La réaction de fixation du complément effectuée avec le sérum des malades, s'avère positive en présence des ovoantigènes hodgkiniens et ornithosiques. IV. La réaction de fixation du complément effectuée avec le sérum standard antiornithosique, donne des réactions positives avec l'antigène hodgkinien; cependant, les taux de ces réactions sont inférieurs à ceux obtenus avec l'antigène ornithosique. V. On envisage la possibilité que ces germes appartiennent au groupe pararickettsien; il reste toutefois à préciser leur identité avec les germes ornithoso-psittacosiques, avec lesquels ils ont des fractions antigéniques communes. VI. La réaction de fixation du complément avec l'ovoantigène hodgkinien s'avère utile pour le diagnostic de laboratoire de la lymphogranulomatose maligne.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1433-8491
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Chronaximetrische Untersuchungen wurden in 3 Familien mit heredofamiliären Nervenerkrankungen (familiäre spastische Spinalparalyse, familiäres Auftreten von peripherer Facialislähmung, hereditäre Atrophie der Mm. pectoralis) vorgenommen. Diese Untersuchungen zeigten uns: 1. Daß manchmal auch Mitglieder der betroffenen Familie, die sonst keine klinischen Anzeichen einer Störung von Seiten des Nervensystems aufweisen, dennoch eine funktionelle Minderwertigkeit derjenigen Systeme haben, welche bei anderen Familienmitgliedern evident erkrankt sind. 2. Daß der Polymorphismus gewisser heredofamiliärer Nervenkrankheiten nur durch quantitativ verschiedene Grade der Störung zustande kommt, daß aber im Grunde sämtliche Systeme, die bei den verschiedenen Familienmitgliedern erkrankt sind, auch bei jedem einzelnen Mitglied minderwertig sind, wenn auch der Grad dieser funktionellen Minderwertigkeit zu klein ist um klinische Symptome hervorzurufen.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Previous research allowed us to develop highly efficient electron emissive metal-dielectric (MD) structures, which are suitable to be used as sources of secondary electrons in electron cyclotron resonance ion sources (ECRIS). First tests have been performed replacing the stainless steel disk of the Frankfurt 14 GHz ECRIS by a MD structure. This method was recently extended by inserting a MD cylinder (150 mm long and 58 mm in diameter) into this source. The experiments were performed with pure argon as source gas and with gas mixing (argon+oxygen). In this contribution, the performance with MD cylinder is compared to that of the standard source (stainless steel plasma chamber) and to the case, where a cylinder of technical aluminum was installed. With the MD cylinder the yield of highly charged ions from the ECRIS are significantly enhanced. For Ar16+ ion current enhancement factors of up to 50 were obtained. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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