Tissue-specific DNaseI hypersensitive sites in the 5''-flanking sequences of the tryptophan oxygenase and the tyrosine aminotransferase genes.

The genes for tryptophan oxygenase (TO) and tyrosine aminotransferase (TAT) are expressed in a tissue- and development-specific manner and are regulated by glucocorticoids (TO and TAT) and glucagon or its intracellular mediator cAMP (TAT) in rat liver. We have analyzed the chromatin structure of these genes in the vicinity of the 5' ends with regard to DNaseI hypersensitivity and have found DNaseI hypersensitive sites upstream of each of the promoters. Mapping of this region reveals three closely spaced cleavage sites near the TO promoter and a doublet of sites near the TAT promoter. In both genes additional cleavage sites are found further upstream. All hypersensitive sites of both genes are absent in kidney nuclei and therefore appear to be specific for the tissue expressing the genes. A correlation of expression and modified chromatin structure was also observed in a hepatoma cell line expressing TAT but not TO: hypersensitive sites are present in TAT but not in TO chromatin. Upon glucocorticoid induction an additional hypersensitive site is detected approximately 2 kb upstream of the TAT promoter in liver and hepatoma cells.     

Influence of colchicine treatment on chromosome number and growth rate of tissue cultures of Valeriana wallichii DC

Cell cultures of Valeriana wallichii were treated with 0.05%, 0.2% and 0.5% of colchicine. The treatment with 0.05% and 0.2% colchicine resulted in well growing cultures. At the highest dose the cells died. The colchicine treatment could be repeated after six alkaloid free passages. The chromosome numbers shifted to polyploidy (n>96) under the treatment but had a strong tendency to the initial pattern.Part VI of a series on tissue cultures of Valerianaceae species.     

Nucleotide sequence of the gene, protein purification and characterization of the pSC101-encoded tetracycline resistance-gene-repressor

The nucleotide sequence of the pSC101-encoded tetracycline repressor gene (tetR) was confirmed. The deduced amino acid sequence is compared to that of other repressor proteins. To overproduce the repressor protein, tetR was placed under the control of bacteriophage lambda promoter pL. Tet repressor protein was purified to homogeneity and shown to bind specifically to two tet operators and also to tetracycline (Tc). The inducer function of Tc is demonstrated by the loss of the specific binding between the tet operator DNA and the Tet repressor-Tc complex.     

Fully automated and fast image analysis of autoradiographs with a TAS-Leitz. Determination of size,Feulgen fluorescence and grain counts of individual nuclei and their evaluation by a simplified cluster analysis

Summary A fully automatic analysis system based on television image analysis was developed to measure simultaneously three parameters in individual nuclei of microscopic autoradiographs prepared from mouse jejunal crypt cell squashes and ascites tumor cell smears: size, Feulgen fluorescence and reflection from silver grains. A dark light camera with an image intensified silicon tube (RCA-ISIT), an automatic scanning stage and an autofocus device were fitted to a Leitz-TAS microscope. The camera permitted localization of Feulgen stained nuclei and measurement of area and light intensity by means of incident of light fluorescence in the red. After automatic changes of the Opak-illuminator silver grains were determined by means of polarized incident light reflected from the grains in the blue. A 25 x oil objective (aperture 0.75) yielded sufficient resolution for measurements. The nadir between the proportions of labeled and unlabeled nuclei was calculated from the data of one specimen on a PDP-computer using a new algorithm based on the minimal variance of the logarithm of reflected light per nucleus. Labeling indices determined by visual grain counting and by automatic analysis of the autoradiographs were well correlated (r=0.87 to 0.92). Visual grain counts/nucleus and reflected light/nucleus correlated well when individual nuclei were compared (r=0.92 to 0.97) or means of labeled nuclei of various specimens prepared during a 5 year period (r=0.90 to 0.93). Quenching of nuclear Feulgen fluorescence was minimal. The optimal labeling range is 30–100 grain counts/nucleus. The time interval between measurements of two specimens was 25 min for a squash of approximately 350 crypt cells within a 3 mm× 3 mm field, and 20 min for a meandering scan with 1,000 ascites tumor cells.     

Peptide transport in yeast: utilization of leucine- and lysine-containing peptides by Saccharomyces cerevisiae.

A variety of leucine-containing di- and tripeptides and two lysine-containing dipeptides supported the growth of strain Z1-2D, a leucine, lysine auxotroph of Saccharomyces cerevisiae. However, (Lys)2, (Lys)3, (Lys)4, and (Lys)5 as well as Gly-Leu-Gly, three tetra- and one pentapeptide containing leucine were not utilized by the mutant. Cellular peptidases released leucine or lysine from all of these non-growth-supporting peptides, suggesting that the failure of strain Z1-2D to utilize these compounds reflects their failure to enter the yeast. Competition studies employing phenylalanine or non-leucine-containing peptides showed that the uptake of peptides into S. cerevisiae Z1-2D is distinct from that of amino acids and that di- and oligopeptides may share a common transport system. The failure of strain Z1-2D to utilize any peptide larger than (Leu)3 may indicate a transport size limit. Such a size limit would influence the construction of models that explain the action of yeast mating factors.     

Changes in phospholipids of Saccharomyces cerevisiae associated with inositol-less death.

Two inositol-requiring strains of Saccharomyces cerevisiae were examined for changes in levels of phospholipids occurring after inositol deprivation. Lack of inositol results in loss of cell viability (inositol-less death) and in very large increases in two phospholipid precursors, phosphatidic acid and CDP-diacylglycerol; the accumulation of other glycerophospholipids continues for a considerable time at normal rates. Phosphatidylinositol accumulation does not occur in the absence of inositol; however, the further metabolism of this lipid continues, with 80 to 90% of this lipid disappearing. This disappearance is matched by increases in the phosphoinositol containing sphingolipids and extracellular glycerophosphoinositol. These changes are not observed when growth is blocked by cycloheximide or by omission of lysine from a lysine auxotroph, most lipids continuing to accumulate long after growth stops. There appears to be no close coordination in the synthesis of the major yeast phospholipids or between protein synthesis and phospholipid synthesis. However, despite very large changes in the composition of yeast phospholipids that can be achieved by altering culture conditions, it appears that the average charge per phospholipid molecule remains fairly constant.     

Windrichtung und Vegetationsdeckung am Nest der Silberm?we(Larus argentatus)

Zusammenfassung An 1047 Silbermöwen-Nestern auf den Watteninseln Mellum und Memmert wurden 1979/80 ermittelt (Abb. 1): Grenzrichtungen der Vegetationsstände 1–3 (1: Vegetationsstand größter Winkelgröße) und Nest-Zugänge 1–3, ihre Winkelgrößen und mittleren Richtungen. Mehr als 80% der Nester waren zu 40–90% von Vegetation umstanden (Abb. 2). Die Winkelgröße des Gesamtvegetationsstandes betrug auf Mellum 212°, auf Memmert 205° (Tab. 1). Die Nestzugänge hatten eine geringere Winkelgröße als die Vegetationsstände (Tab. 1, Abb. 3). Die Silbermöwe bevorzugte demnach Nestplätze, die von Vegetation schützend umgeben sind. Der Vegetationsstand 1 befand sich bevorzugt auf der westlichen (= Hauptwindrichtung), der Zugang 1 auf der östlichen Nestseite (Tab. 2, Abb. 4). Die Verteilung der Gesamtvegetation zeigte entsprechende Vorzugsrichtungen (Abb. 6). Im Vergleich zu 1979 war 1980 eine Verlagerung der Vorzugsrichtung des Vegetationsstandes 1 um 50–60° von West nach Nord festzustellen (Tab. 2, Abb. 4). Ein Vergleich der mittleren Windrichtungen beider Jahre zeigte eine gleichsinnige Richtungsänderung (Abb. 5). Auf den zwei untersuchten Probeflächen Mellums ließ sich eine Auswahl des Nestplatzes im Hinblick auf Sichtschutz gegen Nachbarn nicht nachweisen (Tab. 3). Die mögliche Funktion der nestumgebenden Vegetation als Wind- und Wetterschutz wird diskutiert.

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Vegetation surrounding Herring Gulls'(Larus argentatus) nests in relation to wind direction

Summary The following measurements were taken for a total of 1047 Herring Gulls' nests on the North Sea islands Mellum and Memmert (West Germany) in 1979 and 1980 (cf. Fig. 1 for terminology): limiting directions, angular sizes, and mean directions of the surrounding vegetation-stands 1 to 3 (1 = vegetation-stand with largest angular size), and of the entrances 1 to 3. For more than 80% of the nests, 40–90% of the circumference were surrounded by vegetation (Fig. 2). The mean angular size of the total vegetation-stand was 212° on Mellum and 205° on Memmert (Tab. 1). The nest entrances had a smaller angular size than the vegetation-stands (Tab. 1, Fig. 3). This shows the Herring Gull's preference for nest sites protected by surrounding vegetation.Vegetation-stand 1 was preferably orientated towards the west (= main wind direction), nest entrance 1 towards the east (Tab. 2, Fig. 4). The distribution of the total vegetation showed corresponding preferred directions (Fig. 6). A comparison of the years 1979 and 1980 revealed a shift of 50°–60°, from west to north, for the preferred direction of vegetation-stand 1 (Tab. 2, Fig. 4). A similar shift could be found for the mean wind direction (Fig. 5). For the two study plots on Mellum, a nest site selection favouring visual isolation from neighbours' nests could not be demonstrated (Tab. 3). The possible function of nest-surrounding vegetation as a shelter against wind and weather is discussed.

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Herrn Dr. Friedrich Goethe zur Vollendung des 70. Lebensjahres gewidmet     

Analysis of highly repeated DNA sequences of rat with EcoR1 endonuclease

Cleavage of rat liver nuclear DNA with EcolR1 restriction endonuclease yields 14 discrete fragments ranging from 2300 to 93 base pairs in length, representing approx. 10.5% of the rat genome. Fragments of 1500, 180, and 93 base pairs are reiterated over 100 000 times; fragments of 2300, 880, 290, and 200 base pairs are reiterated over 20 000 times; the remaining fragments are present in over 1000 copies per genome. When compared to whole rate DNA, 11 were 1-5% richer in A . T base pairs and five were 1.5-2.5 times more methylated. From the criteria of the banding patterns in complete and incomplete digests, base composition and extent of methylation, none of these fragments appeared to be generated as oligomers of a basic shorter repeat. The reassociation of EcoR1 fragments was monitored on hydroxyapatite and by S1 nuclease treatment in order to assess band reiteration frequency and the possibility of interpersion or short internal repeats. The renaturation of the four smallest EcoR1 fragments gave no indication of short internal repeats from hyperpolymer formation nor interpersion with lower frequency sequences by size reduction after S1 nuclease treatment. Anomalous renaturation of several large fragments was observed, possibly due to internal repeats.