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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 9 (1972), S. 83-104 
    ISSN: 1432-1424
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Plasma membranes were isolated under hypotonic conditions from rat and mouse livers and five hepatomas, i.e. one rather anaplastic rat hepatoma (and its subline) and three well-differentiated mouse hepatomas. All these membranes contained some 25% protein soluble in 0.15m NaCl. Evidence is presented that this protein is mainly, if not exclusively of nonmembranous origin. Protein/phospholipid P (P=phosphorus) ratios did not differ significantly for the various plasma membrane species except the rat-hepatoma subline, which showed a markedly lower ratio and was thus identified. Hepatoma membranes contained more P of a nonphospholipid nature than did liver membranes and to this increase contributed in all instances an increased RNA content and in some cases also an increased DNA content. The presence of DNA in these plasma membranes is artefactual, but that of RNA is more complicated. Artefactually, Ca2+-associated RNA of low mol wt and soluble in 0.15m NaCl, and residual RNA (genuine?, in liver membranes less than 1% in respect of protein) have been demonstrated. The increase in hepatoma-membrane RNA is attributed to the ribosomal RNA of the few microsomal vesicles which are structurally connected with these plasma membranes. The sialic acid content and the percentage of neuraminidase-resistant sialic acid of hepatoma as compared with liver membranes was either similar or changed, depending on the hepatoma strain. Gelfiltration of trypsin-released peptides of liver plasma membranes showed hexosamine and hexose to be confined to the sialic acidcontaining fractions. In spite of quantitative differences among fractions, the relative contents of the three carbohydrates in the combined fractions were (about) similar to those in intact liver membranes. Similar experiments with the rat-hepatoma membranes showed a changed carbohydrate expression.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 184 (1959), S. 2024-2025 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Recently Quastel and Bickis3 and Ibsen et al.4 determined the ratio of the lactate production by ascites tumour cells to the difference between the oxygen consumption of the cells in the absence and presence of glucose (AO). They found that the accumulation of lactate accounted for the decreased ...
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Previous investigators2,5 reported that several oxidizable substrates, including succinate, markedly and instantaneously accelerated the swelling of fresh liver mitochondria from the rat. However, in our control experiments carried out with freshly isolated (0-3 M sucrose) mouse and rat liver ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 200 (1963), S. 364-364 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Post-mitochondrial fractions from rat liver and three transplanted rat hepatomas were prepared and incubated anaerobically with glucose-6-phosphate under the conditions mentioned in the legend of Table 1. a-Glyeeroiphosphate was measured by the conventional enzymatic method2. Table 1 shows the ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 64 (1960), S. 22-34 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die Schwellung von in 0,30 M Saccharose isolierten und in Saccharose-Tris von pH 7,4 bei 22±1°C inkubierten Mitochondrien aus Mäuse- und Rattenlebern wurde gemessen nach Zusatz von Succinat, Adeninnucleotiden (10−5 M), Malonat, Thyroxin und DNP, allein und in verschiedenen Kombinationen. Sowohl die spontane wie die thyroxininduzierte Schwellung frischer Mitochondrien wird durch Succinat und noch mehr durch Succinat und Adeninnucleotide (ADP≥ATP≫ oder 〉 AMP) gehemmt. Die Hemmung wird aufgehoben durch Malonat oder DPN. Auf die Hemmung der Schwellung von frischen Mitochondrien durch Succinat folgt eine Phase schneller Schwellung. Allmähliche Alterung oder wiederholte Waschungen von den Mitochondrien vor der Inkubation führen zu einer Verringerung oder Aufhebung des hemmenden Effektes des Succinats. Daraus wird gefolgert, daß die mitochondriale Schwellung von dem Grade der Eigenstabilität der isolierten Partikel abhängig ist.
    Notes: Summary The swelling of rat and mouse liver mitochondria, isolated in 0.30 M sucrose and incubated in sucrose-Tris of pH 7.4 at 22±1°C, in response to succinate, adenine nucleotides (10−5 M), malonate, thyroxine, and DNP, separately or in various combinations, was measured. It was found that both the spontaneous and thyroxine-induced swelling of fresh mitochondria were counteracted by succinate and, to a still greater extent, by succinate plus adenine nucleotide (ADP≥ATP≫ or 〉 AMP). The protection was abolished by malonate or DNP. The protection against swelling afforded by succinate to fresh mitochondria was followed by a phase of rapid swelling. Progressive ageing or frequent washing of the particles, prior to their incubation, led to a reduction or abolition of the protective effect. It was concluded that mitochondrial swelling was governed by the degree of intrinsic stability of the isolated particles.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of cancer research and clinical oncology 64 (1960), S. 52-63 
    ISSN: 1432-1335
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Mitochondrien aus Rattenlebern wurden 20–24 Std nach der Verabreichung einer akut-giftigen Menge DMNA (Dimethylnitrosamin) isoliert. Die Partikel wiesen eine sehr gesteigerte Neigung zur Schwellung und eine große Ähnlichkeit mit dem Verhalten von künstlich gealterten Mitochondrien auf. Die DMNA-Leberzellenmitochondrien sind also viel weniger stabil als normale. Dem entspricht auch eine gewisse funktionelle Labilität hinsichtlich gesteigerter ATP-Spaltung, verringerter P:O-ratio und Mangel an DPN-gekuppelten Oxydationen. Andere Äußerungen des toxischen Effektes des DMNA auf die Rattenleber, wie sie durch biochemische und elektronenmikroskopische Untersuchungen festzustellen sind, werden kurz besprochen und verglichen mit solchen nach wiederholter Fütterung kleinerer Mengen von DMNA während längerer Zeit. Während die Feinstruktur der Hauptmasse der Lebermitochondrien nach toxischen Dosen von DMNA unverändert blieb, war nun ein Verlust von Innenstruktur (sowohl Cristae wie Matrix) zu beobachten. In ausgesprochenem Gegensatz dazu war das Schwellungsverhalten aber vollkommen normal. Das doppelte Paradox (Normalstruktur/abnormale Schwellung; „abnormale” Struktur/normale Schwellung) wird zum Teil aufgehoben durch Experimente, welche auf die Möglichkeit hinweisen, daß die bei toxischen Dosen DMNA vermehrten nicht-strukturell gebundenen Fette in der Leber an Mitochondrien adsorbiert werden während ihre Isolierung, und diese schädigen könnten.
    Notes: Summary Mitochondria were isolated from the livers of rats 20–24 hours after the administration of an acutely toxic dose of DMNA. The particles showed a much increased tendency to swell in the assay systems described in the preceding papers, and closely resembled previously aged normal liver mitochondria. The conclusion was drawn that the DMNA-liver particles were much less stable than their normal counterparts. The latter conclusion was corroborated by the finding of a certain measure of functional lability of the particles: increased ATP-splitting, decreased P:O ratios and some deficiency in DPN-linked oxidations. Other manifestations of the toxic effect of DMNA on rat liver, revealed by biochemical and electron microscopic examinations, are briefly discussed and compared with those observed after repeated administration of low doses of DMNA during prolonged periods. Pertinent to the present study was the finding that the fine structure of the major part of liver mitochondria following the toxic dose of DMNA was not altered, whereas after prolonged administration of DMNA in low amounts some loss of internal structure (both cristae and matrix) was observed. In sharp contrast to this observation stood the finding that the in vitro pattern of swelling of the latter particles was completely normal. The double paradox (normal structure/abnormal swelling; ‘abnormal’ structure/normal swelling) was partly resolved by the results of experiments which pointed to the possibility that the non-structurally-bound fats, accumulated in livers of rats following the toxic dose of DMNA, might become adsorbed onto the mitochondria during their isolation, and afflict damage.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Current genetics 12 (1987), S. 471-474 
    ISSN: 1432-0983
    Keywords: Aspergillus nidulans ; Mutation induction ; Mutagen dose ; Mutant yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Since the yield of mutants per surviving cell increases in general with increasing dose of mutagen, it has often been concluded in the literature that it is the most efficient to apply high mutagen doses so that most spores are killed. As high doses of mutagen produce chromosome rearrangements and unnoticed mutations which disturb the genetic background, the relationship between mutant frequency and survival was analyzed with Aspergillus nidulans as a model. It is shown that for different types of mutants the highest mutant yield is obtained at low mutagen doses (20–50% survival). Mutant frequency increases with increasing dose of mutagen but levels off and even decreases at higher dosages. There is no simple linear relationship between mutant frequency and the logarithm of the mutagen dose or the logarithm of the surviving fraction. If appropriate enrichment procedures are also available auxotrophic mutants can best be isolated at low doses of mutagen. Taking into account the disturbance of the genetic background, mutation induction should be done preferentially at a survival level of at least 70%.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0983
    Keywords: Transformation of Aspergillus ; Conidial protoplasts ; Multicopy/tandem integration ; Gene amplification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Conidial protoplasts of an A. nidulans amdS deletion strain (MH1277) have been transformed to the AmdS+ phenotype with a plasmid carrying the wild type gene (p3SR2). Optimalisation of transformation and plating conditions now has resulted in frequencies of 300–400 transformants per μg of DNA. Analysis of DNA from AmdS+ transformants of MH1277 showed that transformation had occurred by integration of vector DNA sequences into the genome. In virtually all these transformants multiple copies of the vector were present in a tandemly repeated fashion, not preferentially at the resident, partially deleted amdS gene. It is suggested that the observed integration phenomena are dependent on the genetic background of the A. nidulans strain, used for transformation. A model to explain the tandem type of integration is proposed.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 11 (1955), S. 353-354 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Mitochondrien aus kleinen und grossen Spontanhepatomen bei F1(C57Bl×C3He) Mäusen weisen verschiedene Adenosintriphosphataseaktivitäten auf, was sich 1. an der Hemmung der Fettsäureoxydation normaler Lebermitochondrien nach Zugabe von Tumormitochondrien und 2. an der Fettsäureoxydation der Hepatommitochondrien selbst zeigen lässt. Die Mitochondrien gewisser Tumoren vermochten Caprylsäure nur zu oxydieren, wenn die Adenosintriphosphatase möglichst wenig aktiviert war durch Zugabe von Verseen zum Aufarbeitungsmedium.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 203 (1964), S. 77-78 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Pette and Ruga3 have very recently demonstrated that potassium cyanide causes the dismutation of methylglyoxal. which contaminates the triosephosphate esters used as substrate in the enzyme assay, to pyruvate, which is then reduced by added NADH2 and the lactic dehydrogenase present in the ...
    Type of Medium: Electronic Resource
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