ADP-ribosylation of nucleolar proteins in HeLa tumor cells

ADP-ribosylation reactions in nucleoli of exponentially growing HeLa cells were studied. Isolated nuclei or nucleoli were labeled with ³²P-NAD; then the nucleolar proteins were analyzed by 1-dimensional and 2-dimensional polyacrylamide gel electrophoresis (PAGE) and modified proteins were detected by autoradiography. The labeled nucleolar proteins were also chromatographically fractionated on DEAE-cellulose. Electrophoretic analysis of total nucleolar and chromatographically purified proteins revealed that besides nuclear ADP-ribosyltransferase and histones two characteristic nucleolar phosphoproteins numatrin/B23 and nucleolin/C23 were modified by ADP-ribosylation.     

Catecholaminergic contributions to the neuronal machinery of the olfactory bulb: aftoradiographic, immunohistochemical and evoked feild potential studies

aftographic exeperiments on the localization of radiolabelednoradrenaline, dopamine and dopa, as well as immunohistochemicalstudies on hydroxylase-like activity, are summarized and comparedin both rat and turtle olfactory bulbs. Evoked field potentialstudies on effects of dopamine are also discussed. The histochemicalstudies suggest that dopaminergic periglomerular neurons arethe most significant cellular component of the catecholaminergicsystem in the olfactory bulb of both species. Scattered fluorescentcell group was also present in the internal plexiform layerand superficial granule cell layer of the turtle olfactory bulb.Other fibres, not related to intrinsic bulbar neuronal cellbodies, were also labeled, mostly in the granule cell layerbut also in the external plexiform layer. These might belongto a centrifugal catecholaminergic system from brain stem neurons.In the in vitro turtle olfactory bulb, dopamine and apomorphinedepressed the amplitude of field potentials evoked by a singlevolley in the olfactory nerve or lateral olfactory tract, andreduced the depression and latency of reponses when paired volleywere delivered. It is suggested that catecholaminergic systemsplay a key role in modulating mitral cell activity through actionsin both superficial (glomerular) and deep (granule) layers.This may involve direct actions, or other, non-catecholaminergicinterneurons.     

Drosophila wingless: A paradigm for the function and mechanism of Wnt signaling

The link between oncogenesis and normal development is well illustrated by the study of the Wnt family of proteins. The first Wnt gene (int-1) was identified over a decade ago as a proto-oncogene, activated in response to proviral insertion of a mouse mammary tumor virus. Subsequently, the discovery that Drosophila wingless, a developmentally important gene, is homologous to int-1 supported the notion that int-1 may have a role in normal development. In the last few years it has been recognized that int-1 and Wingless belong to a large family of related glyco-proteins found in vertebrates and invertebrates. In recognition of this, members of this family have been renamed Wnts, an amalgam of int and Wingless. Investigation of Wnt genes in Xenopus and mouse indicates that Wnts have a role in cell proliferation, differentiation and body axis formation. Further analysis in Drosophila has revealed that Wingless function is required in several developmental processes in the embryo and imaginal discs. In addition, a genetic approach has identified some of the molecules required for the transmission and reception of the Wingless signal. We will review recent data which have contributed to our growing understanding of the function and mechanism of Drosophila Wingless signaling in cell fate determination, growth and specification of pattern.     

Prediction of potential barcoding sites on ITS1 by wavelet transform

For sustainable development, biodiversity conservation and life-quality improvement must be simultaneously considered. Molecular techniques have greatly impacted biotechnology. These methods have, in particular, improved the capability to investigate the fine differences among organisms and, as a consequence, to better investigate the effects on environmental factors on them. We propose an approach to support the optimal selection of molecular probes for barcoding application in many biotechnological fields. The aim of our work is specificity maximization. To this purpose, we have integrated a filter system based on wavelet transforms with biological knowledge about the sequence proneness to mutation and post-translational modification. Specifically, we have tested the proposed method on ITS1 sequences that are a region of the rRNA locus. Our analysis has shown the presence of other local relative stable conformations in addition to known cleavage site. Their characteristics differ within the group of mammals selected for our analysis. These variations could be used to design new species-specific barcoding probes or other quick molecular screening tools.     

Durchflußfluorescenzcytophotometrie für ultraschnelle DNS-Messungen an großen Zellpopulationen

Zusammenfassung Ausgehend vom Leitz-Mikroskopphotometer MPV mit Auflicht-Anregung wird ein Durchflußfluorescenzcytophotometer beschrieben, das es gestattet, die relativen Feulgen-DNS-Mengen von bis zu 1000 Zellen pro Sekunde zu bestimmen. Die Meßwerte werden in einem Impulshöhenanalysator klassifiziert und gespeichert. Auf Abruf wird der Speicherinhalt analog als Histogramm ausgeschrieben oder digital als Zahlenfolge ausgedruckt.Das Vorgehen bei der Zellsuspensionsherstellung, Fixierung, Hydrolyse und Färbung mit dem Feulgen-Farbstoff Akriflavin wird dargelegt.Anwendungsbeispiele werden besprochen.

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Flow-through-cytophotometry for ultra-rapid DNA measurement of large cell populations

Summary A flow-through cytophotometer based upon the Leitz-microscope photometer (MPV) is described. The light source is a high pressure Xenon arc HBO 100 in an arrangement for epiillumination.The flow system is designed in such a way that each cell, after previous Feulgenstaining in aqueous suspension, has to pass through the focal plane of the objective. This is achieved by a self-constructed flow channel with a vertical fluid stram carrying the stained cells along the optical axis of the microscope at a flow rate of 100 to 1000 cells per sec. After passage through the focal plane with simultanneous registration of the highest fluorescence reading the cells are flushed off by a horizontal water current.The fluorescence light impulses emitted by the cells are classified and stored by an impulse height discriminator, from which they may be recalled either analogically as a histogram (DNA distribution pattern) or digitally as a series of numbers.In addition, the fluorescence impulses can be visualized at the screen of an oscillograph. The flow rate of the fluorochromized cells is determined by means of a counter unit.The steps of preparation of the cell suspension as well as fixation, hydrolysis and Feulgen-staining with acriflavine-Schiff of the suspended tissue cells is described in detail.The possibilities of application of the instrument as a cyto-morphometric approach to cytology and cytochemistry automation are discussed.

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Mit Unterstützung des Bundesministeriums für Jugend, Familie und Gesundheit.

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Zu besonderem Dank sind wir der Fa. Leitz, Wetzlar, verpflichtet. Sie stellte kostenlos das Mikroskopphotometer mit Lichtmeßeinrichtung zur Verfügung und ermöglichte uns die Überprüfung der Apparatur in ihren Laboratorien. Den wissenschaftlichen Mitarbeitern der Fa. Leitz, Herrn Ing. J. Rzeznik und Herrn Dipl. Phys. H. Wasmund, danken wir für ihre Beratung und die anregende Diskussion des Manuskriptes.Herrn Ing. H. Eipel, Fa. Elektronik Service, Frankfurt, sei für die Beratung bei Problemen der Impulsanalyse und Durchsicht des Manuskriptes gedankt.Ebenfalls danken wir Fräulein M. Schaden für die gewissenhafte und selbständige Durchführung der biologischen Versuche.     

Effects of food type, feeding frequency, and temperature on juvenile survival and growth of Marisa cornuarietis (Mollusca: Gastropoda)

Abstract. The present experiments are part of a larger study designed to investigate the influence of husbandry parameters on the life history of the ramshorn snail, Marisa cornuarietis, in order to identify suitable husbandry conditions for maintaining multi‐generation populations in the laboratory for use in ecotoxicological testing. In this paper we focus on the effects of a combination of food types and feeding frequencies (i.e., the frequency with which the snails were offered food) on juvenile growth and survival at different temperatures. Offspring produced in the laboratory by wild specimens of M. cornuarietis, from Puerto Rico, were used to test the effects of three types of food (lettuce, alginate with fish food, alginate with snail mix) fed at three frequencies (given ad libitum on 4/4, 2/4, or 1/4 d) on juvenile survival and growth. The 4‐d feeding regimens were repeated four times, giving a total of 16 d for the experiments. The experiments were conducted at two temperatures (22° and 25°C) under a 12 h light:12 h dark photoperiod. Juvenile growth rates increased with increasing feeding frequency for all food types. The most rapid growth rates occurred in the high‐frequency lettuce treatments and the slowest growth rates in the low‐frequency lettuce and alginate with snail mix treatments. Juvenile snails grew faster at 25° than at 22°C, and mortality was about twice as high at the lower temperature. Growth rates were used to provide a rough estimate of time to maturity, which was determined to take about twice as long at 22° than at 25°C. The results showed that lettuce is the best food if supplied in abundance, but effects on growth are very dependent on feeding frequency and temperature. We conclude that 25°C is a more appropriate temperature for maintaining populations than 22°C, that lettuce provides a suitable food source, and that food should be supplied continuously for husbandry and toxicity testing of populations of M. cornuarietis.