DDD: Distributed Dataset DNS

Cluster Computing - The advent of inexpensive data storage has resulted in larger and larger datasets as the cost of pruning data becomes more expensive then storing it for future insights. This...     

Heterochromatin,repetitive DNS und Nukleolen in Leberzellen von Microtus agrestis

Zusammenfassung Die Zellstruktur von Leberzellen der Erdmaus, Microtus agrestis, wurde nach Giemsafärbung, Feulgenbehandlung, Behandlung mit Ribonuklease und nach Färbung des konstitutiven Heterochromatins untersucht. Das konstitutive Heterochromatin ist in Leberzellen nicht heteropyknotisch, das fakultative Heterochromatin ist im weiblichen Geschlecht als Sexchromatinkörperchen sichtbar. Bestimmungen des relativen DNS-Gehalts ergaben, daß die Zahl der Sexchromatinkörperchen der Ploidie der Zellkerne proportional ist. Die Nukleolen liegen in Hepatozyten oft randständig; in 59% der diploiden Zellkerne sind 2 Nukleolen enthalten. Nach Anfärbung der repetitiven DNS werden oft auch die Nukleolen gefärbt, nach Ribonukleasebehandlung tritt dieser Effekt nicht auf. Das konstitutive Heterochromatin wird in Form von 2 langen fädigen Strukturen sichtbar.

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Heterochromatin, repetitive DNA and nucleoli in liver cells of Microtus agrestis

Summary The nuclear structure of parenchymal liver cells of embryo and adult Microtus agrestis was studied in smear and section preparations after staining with Giemsa solution and treatment according to Feulgen, after treatment with ribonuclease and after specific staining of constitutive heterochromatin. In liver cell nuclei only the facultative heterochromatin is heteropycnotic, a sex chromatin body is observable in female but not in male animals. Constitutive heterochromatin is not heteropycnotic in liver cells. Measurements of the relative DNA content showed that nuclei with one sex chromatin body are diploid; tetraploid nuclei possess two and octoploid nuclei four sex chromatin bodies. Solely in the diploid cell nuclei of the intrahepatic gall ducts two large chromocenters are found. The nucleoli in hepatocytes often lie at the perimeter of the nucleus. 17% of the diploid nuclei contain one nucleolus, 59% two nucleoli, 23% three and 1% four. After staining of repetitive DNA, the nucleoli often become stained as well; after treatment with ribonuclease this effect does not occur. The constitutive heterochromatin becomes visible in form of two long, threadlike structures. After longer periods of dissociation the sex chromatin body ceases to be visible. Sex chromatin and constitutive heterochromatin are contiguous to the nucleoli.

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Mit dankenswerter Unterstützung durch das Bundesministerium für Bildung und Wissenschaft der Bundesrepublik Deutschland.     

Verteilung und Aufteilung der DNS bei einigen Cyanophyceen,festgestellt durch ihre DAPI-Fluoreszenz

The DNA of Blue-Green Algae may be specifically and most efficiently elucidated by the combined use of the fluorochrome DAPI and DNAse treatment. InChroococcus turgidus andSynechococcus aeruginosus it forms a network which usually is positioned at the periphery of the centroplasm. At the beginning of cell division it seems to be invaginated by the ingrowing cell wall. Later it must be distributed by other means because two equal parts are connected by a number of fine and straight DNA threads. InOscillatoria limosa usually all parts of the centroplasm are interspersed with the DNA network. In surface view, the DNA occasionally seems to consist of a number of independant rods, but in reality these are connected to the general network. Division apparantly occurs by ingrowth of the crosswall and usually results in equal daughter nuclear equivalents although occasionally they are unequal. Four strains ofMicrocoleus vaginatus were found to have nuclear equivalents of the same general appearance as inOscillatoria limosa.

     

Trennung der effekte von transmutation und strahlung nach einbau von radionukliden in die DNS

Summary Among the various methods for studying the relative effects of transmutation and radiation of incorporated nuclides, simulation of beta radiation by external gamma exposure is of practical importance.Self-irradiation and mutual irradiation of the labeled cells cannot be neglected in any case. Furthermore, additional hypothetical and experimental problems may arise from using either external beta radiation or different isotopes of an element.By means of external gamma irradiation on the other hand, this being equivalent to the internal beta radiation from a microdosimetrical point of view, the radiation effect of the nuclide alone can be observed without any modification of other experimental parameters. To determine such equivalent gamma radiation for labeled cell nuclei ofVicia faba roots, the authors applied the Monte Carlo Method to the beta spectra of³²P,³H,¹⁴C and¹³¹J, to the energy-dependent LET and to different cell diameters. The existence of secondary particle equilibrium inside the nuclei during gamma exposure was assumed. For certain radionuclides and cell sizes it is possible to calculate gamma spectra which induce energy spectra in the nuclei similar to those caused by the beta particles originating in the nuclear DNA.

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Trennung der effekte von transmutation und strahlung nach einbau von radionukliden in die DNS

Zusammenfassung Unter den verschiedenen Methoden zur Untersuchung der relativen Wirkung von Transmutation und Strahlung inkorporierter Nuklide kommt der Simulation der Betastrahlung durch eine externe Gammastrahlung praktische Bedeutung zu. Nicht immer kann man nämlich davon ausgehen, daß die Selbstbestrahlung der zu untersuchenden Objekte vernachlässigt werden kann. Auch bringt sowohl die Verwendung einer äußeren Betastrahlung als die verschiedener Isotope desselben Elements häufig zusätzliche prinzipielle und experimentelle Probleme mit sich. Hingegen kann durch eine der Betastrahlung äquivalente Gammastrahlung der Strahleneffekt des Nuklids allein ohne Veränderung der Kultur- und Inkorporationsbedingungen untersucht werden. Allerdings ist es keineswegs einfach, diese äquivalente Gammastrahlung auf rein theoretischem Wege zu ermitteln. Immerhin können mit Hilfe des skizzierten Verfahrens zumindest in einigen Fällen Gammaspektren berechnet werden, die im Innern des Zellkerns vonVicia faba, Energieabsorptionsspektren erzeugen, die denen von im Zellkern emittierten Betateilchen ähnlich sind.Unter Berücksichtigung des in der Diskussion Gesagten läßt sich das Verfahren sicherlich verbessern. Auch fßr andere Objekte und Objektverteilungen dürften sich dann äußere Strahlenquellen ermitteln lassen, mit denen der relative Anteil von Transmutation und Strahlung an der Gesamtwirkung des radioaktiven Zerfalls untersucht werden kann.

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Eingegangen am 26. August 1974     

Über die Adsorption von DNS in der Grenzfläche Quecksilber–Elektrolyt

The adsorption of deoxyribonucleic acid (DNA) in the mercury–electrolyte interface has been investigated. The effect of this adsorption on the differential capacity of the electrical double layer between a polarized mercury surface and an 0.15M NaCl solution containing DNA was measured by means of the alternating current polarography (Breyer polarography). The effective alternating current ? under actual conditions (adsorption processes only, small electrolytic resistance, small alternating current frequency, and alternating current amplitude) is directly proportional to the differential double layer capacity. The combination of this method with the application of a stationary mercury drop electrode allows the coverage of the electrode to be followed, continuously in the range 0.2 sec, to about 60 sec. The diffusion is the rate-controlled step of the adsorption kinetics. Therefore the lowering of the alternating current ? by the adsorbed DNA is proportional to the surface concentration for partly covered surface and reaches a constant value after the surface becomes fully covered. Adsorption of further layers does not affect the differential capacity. This makes it possible to determine the maximum surface concentration of the DNA. For that it is necessary to determine the diffusion coefficient of DNA. This was done directly by Strassburger and Reinert in our institute. The surface concentrations of the native DNA and the relative surface concentrations of the denatured DNA in dependence on the potential of the polarized mercury surface was estimated. Both surface concentrations show a pronounced dependence on the potential with a minimum of the surface concentration around ?0.4 V with respect to the normal calomel electrode. This property may be caused by the structure of the adsorption layer depending on the potential. That means that only several segments at the rigid DNA molecules are adsorbed and the other ones remain in the solution near the surface. The adsorption in the neighborhood of the electrocapillary zero potential at ?0.4 V is strongest, and therefore the fraction of the adsorbed segments has a maximum. At these potentials consequently the maximum coverage is already reached at relatively low surface concentrations. Opposite to this is Miller's hypothesis, that native DNA preserves its double helical structure when adsorbed on a negatively charged mercury surface, whereas unfolding occurs on a positively charged mercury surface. Miller's hypothesis is supported by facts that the surface concentration of the denatured DNA should be independent of the potential and should be equal to the surface concentration of the native DNA at a positively charged mercury surface. But an evaluation of Miller's diagrams by no means gives an independence on the potential of the surface concentration of the denatured DNA and no accordance between the surface concentrations of denatured and of native DNA's at the positively charged mercury surface. Moreover Miller compared different DNA samples with different moleculer weights and possibly with different molecular weight distributions. Both the molecular weight and the molecular weight distribution have a pronounced influence on the surface concentration. Therefore this accordance mentioned above is not evident. The critical inspection of Miller's work and the own investigation lead to the conclusion that an unfolding or denaturation of native DNA does not take place in the mercury–electrolyte interface.     

Eine Methode zum Nachweis von hydrolytischen Enzymen mit sukzedaner zytophotometrischer Bestimmung von DNS,Histon und Gesamtprotein

Zusammenfassung Bei der zytophotometrischen Bestimmung von Kernproteinen an gemischten Zellpopulationen wie Lymphknoten, Knochenmark oder Milz ist die Zuordnung der jeweils zu untersuchenden Einzelzelle zu einer bestimmten Zellrasse oft schwierig. Durch diesen Unsicherheitsfaktor kann die Aussagekraft derartiger Messungen stark eingeschränkt werden. Um diese Fehlermöglichkeit zu vermindern, wird ein Verfahren beschrieben, welches durch Anwendung zytochemischer Enzymnachweismethoden eine zuverlässige Klassifizierung der zu messenden Einzelzelle vor der anschließend vorzunehmenden eigentlichen quantitativen Analyse derselben Zelle erlaubt, ohne die Meßergebnisse zu beeinträchtigen.

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A method for the demonstration of hydrolytic enzymes with sequential cytophotometric measurement of DNA, nuclear histone and total protein

Summary In cytophotometric analyses of nuclear proteins of mixed cell populations such as lymph nodes, bone marrow or spleen it is frequently difficult to place a single cell to be explored into a precise category of cell types. This factor of uncertainty concerning the classification of cells may substantially reduce the value of those measurements. In order to eliminate or diminish such sources of error a method is described which by means of cytochemical enzyme tracing allows for a reliable classification of single cells to be examined prior to the real quantitative analysis of the same cell without impairment of the results of the measurements.

     

Exclusion of the dysplastic nevus syndrome (DNS) locus from the short arm of chromosome 1 by linkage studies in Dutch families

Familial dysplastic nevus syndrome (DNS) is an autosomal dominant premalignant condition characterized by multiple large moles of variable size and color and a strongly increased risk for cutaneous malignant melanoma. In order to determine the chromosomal localization of the DNS gene, linkage studies were initiated in six large Dutch families. No support was obtained for linkage between the loci for DNS and the rhesus blood group on chromosome 1. Data from additional markers (DNF15S1, D1Z2, FUCA1, D1S17, D1S57, and PGM1) make it possible to exclude the DNS gene from the short arm of chromosome 1 in these Dutch families.     

Metabolic ability and gene characteristics of Arthrobacter sp. strain DNS10, the sole atrazine-degrading strain in a consortium isolated from black soil

Strain DNS10 was the only member that could utilize atrazine as the sole nitrogen source for growth in an atrazine-degrading consortium which was isolated from black soil previously in our laboratory. It belongs to the genus Arthrobacter according to the sequence of 16S rRNA gene and is designated as Arthrobacter sp. DNS10. 16S rRNA gene phylogenetic analysis showed that strain DNS10 was located in a different evolutionary branch comparing with other Arthrobacter sp. atrazine-degrading strains. The degrading genes such as trzN, atzB and atzC harbored in strain DNS10 revealed high sequence similarity with those in Arthrobacter aurescens TC1 and Pseudomonas sp. ADP. These genes enabled the strain DNS10 to decompose atrazine to cyanuric acid. This was further proved by the results that the strain DNS10 (10⁸ CFU mL⁻¹) could degrade the whole atrazine (100 mg L⁻¹) in the medium within 24 h at 30 °C and there was 66.13 ± 2.11 mg L⁻¹ cyanuric acid accumulated at 24 h. These results imply that the strain DNS10 seems to be an excellent atrazine-degrading strain. Furthermore, this paper helps us in the better understanding of the strain evolution by comparing the metabolic ability and gene characteristics of strain DNS10 with other geographically distinct atrazine-degrading strains.     

Fluorescent antibody method

Гыл синтезирован флюоресцентный краситель 1-диметиламинонафтален-5-суляфонил-хлорид и исследовались условия его коньюгации с белка.ми. Концентрация белков и ионная сила раствора в реакцcии не оказывали суцественного влияния на интенсивность связывания, тогда как деиствие pH было противоположным. При всех опытах приименялся одии вид гамма-глобулина, иммунологические свойства которого в результате химической интеракции с данзилхлоридом не менялися. С 1 молекулой гамма-глобулина связывались—В в зависимости от условий опыта—3—9 молекул флюооресцирующего красителя. При длительном отстаивании комплекса белки-краситель при +4° C на-блюдалась неболящая диссоциация, которая не имела существенного влияния на красяцую способностя кончюгата.     

The formaldehyde-fluorescamine method

Summary Formaldehyde reacts with primary amino groups to derivatives which are unable to react with the fluorogenic primary amino group probe, fluorescamine. Paradoxically, however, certain specific cell systems continue to display strong fluorescamine-induced fluorescence after formaldehyde pretreatment. Among such formaldehyde-fluorescamine (FF) positive cell systems are certain peptide- and protein-secreting cells as well as all hitherto investigated types of cancer cells. We have now optimized the cytochemical FF method by using microfluorometry in combination with systematically varied reaction conditions. In addition, the quantitative data indicate that in FF positive cells, formaldehyde pretreatment causes a paradoxical increase in the fluorescence yield with fluorescamine. This has tentatively been ascribed to quenching phenomena, associated with closely spaced primary amino groups. Work with alternative fluorogenic amino group probes (MDPF and OPT) show that these display the same spectrum of tissue selectivity as fluorescamine, but that the latter remains the reagent of choice for the cytochemical FF reaction.