Regulation and characterization of two inducible amino-acid transport systems in Chlorella vulgaris

Glucose or non-metabolizable glucose analogues induce two amino-acid transport systems in Chlorella vulgaris: an arginine system (arginine and lysine) and a proline system (proline, glycine, alanine and serine). the same amino-acid transport systems are induced in the absence of glucose, when the cells are depleted of their nitrogen source as judged by a comparison of K_m values and the lack of additive induction by the two treatments Changes in the concentration of neither internal free amino acids nor of soluble carbohydrate pools correlate prefectly with the induction of amino-acid transport. Also exogenous cAMP had no effect on the induction of transport. Both aminoacid transport systems are able to accumulate free amino acids more than 1000-fold. The accumulation plateau is not due to a steady state of influx and efflux, but rather arises by a shut-off of influx. No significant effux is observed. The biological importance of this frequently observed behaviour in amino-acid transport is discussed.     

Ultrastruktur und polysaccharidanteile der cuticula von Triops cancriformis Bosc. (Crustacea,Notostraca) während der Häutungsvorbereitung

Zusammenfassung Die Cuticula von Triops cancriformis besteht aus Endo-, Exo- und Epicuticula. Die Epicuticula ist aus vier Schichten aufgebaut, die Exocuticula aus 10 und die Endocuticula aus 60–80. Die Schichten der Endocuticula sind aus annähernd oberflächenparallel verlaufenden Mikrofibrillen, die zu Lamellulae zusammentreten, gebildet. Diese Lamellulae atehen senkrecht zur Oberfläche. Die Lamellulae der einzelnen Lagen verlaufen im rechten Winkel zu denen der Nachbarlagen. In Sinnesborsten verläuft so ein Teil der Fibrillen in Längsrichtung, der andere quer zur Längsachse.Polysaccharide finden sich in den Lamellulae, in zwei Schichten der Epicuticula, den Desmosomen und als Glykogengranula in Epidermiszellen.Die Häutung zeigt anscheinend keine Besonderheiten gegenüber anderen Arthropoden.

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Ultrastructure and polysaccharide content of the cuticle of Triops cancriformis Bosc. (Crustacea, Notostraca) during the Molting preparation

Summary The cuticle of Triops cancriformis consists of endo-, exo- and epicuticle. The epicuticle comprises 4 layers, the epocuticle 10 and the endocuticle 60–80 layers. The layers of the endocuticle consist of microfibrils. These microfibrils are almost parallel to the surface of the cuticle and merge into lamellulae. These lamellulae run vertical to the surface. The lamellulae in any one layer are at right angles to the lamellulae in the neighbouring layers. Thus, some of the fibrils in sensory setae are parallel to the longitudinal axis and others are perpendicular to it.Polysaccharides are found in the lamellulae, in two layers of the epicuticle, in the attachment regions and in the glycogen deposits in the epidermis cells.The molting process seems to be similar to the molting process of other arthropoda.

     

Carotenoids of Thiorhodaceae

Summary The isolation, morphology and growth chracteristics of pure cultures of a Thiothece, Lamprocystis and Thiodictyon strain are described.Their carotenoid composition is reported. The Thiothece strain produced in addition to okenone (1), several related ketocarotenoids, among which a demethylated okenone (6) was identified by a small scale total synthesis. Thiodictyon and Lamprocystis produced carotenoids of the rhodopinal (previously warmingone) series, the latter organism contained as major carotenoids a lycopenol (4), not previously found in Nature, and a cross-conjugated lycopenal (2), previously called anhydro-warmingone.Part 7. Acta chem. scand. 21, 2185 (1967).     

Influence ofl-thyroxine,l-triiodothyronine,thyroid stimulating hormone,or estradiol on the cell kinetics of cultured mammary cancer cells

Summary We describe the in vitro influence of 3,5,3′-triiodo-l-thyronine (T₃),l-thyroxine (T₄), a thyroid-stimulating hormone (TSH), and/or estradiol (E₂: chosen as the control of the methodology) on the cell kinetics (cell distribution in the S+G₂+M phases) of mouse MXT and human MCF-7 mammary cancer cells. Experiments were performed by means of a cell image processor, analyzing MCF-7 or MXT cells that had been grown on glass cover slips and whose nuclei had been stained by the Feulgen reaction, which is selective and quantitative (stoichiometric) with respect to DNA. We show that T₃, T₄, and TSH at 0.01 μM dramatically stimulate the cell kinetics of the MXT mouse and the MCF-7 human mammary cancer cell lines. Indeed, the three hormones bring about a significant transient increase in the S+G₂+M fraction as does E₂. Furthermore, our data indicate that E₂ and TSH are antagonistic with regards to MXT or MCF-7 cell kinetics. This work is supported by grants awarded by the IRSIA and the Fonds de la Recherche Scientifique Médicale (FRSM, Belgium).     

Relationship between computerized morphonuclear image analysis and histopathologic grading of breast cancer

A pilot study analyzed the relationship between several morphonuclear parameters and the Bloom-Richardson score for 37 invasive, not-otherwise-specified (NOS) ductal breast carcinomas. The SAM-BA 200 cell image processor and its software were used to measure the nuclear features on Feulgen-stained imprint smears. Two parameters representing the numbers of large and dense chromatin clots and two parameters describing the heterogeneity of the chromatin among nuclei in a specimen evolved in a continuous manner parallel with the Bloom-Richardson score from stages NOS-4 to NOS-8. The systematic measurement of these four parameters on a large series of breast cancers may be able to define an objective and reproducible "scale" of differentiation that could be a helpful tool for pathologists and clinicians.     

Structural gene isolation and prepeptide sequence of gallidermin, a new lanthionine containing antibiotic

Peptide antibiotics containing lanthionine and 3-methyllanthionine bridges, named lantibiotics are of increasing interest. A new lantibiotic, gallidermin, has been isolated from Staphyloccus gallinarum. Here we report the isolation of its structural gene which we name gdmA. In all lantibiotics so far studied genetically, three peptides can be formally distinguished: (i) the primary translation product, which we call the prepeptide; (ii) the propeptide lacking the leader sequence and (iii) the mature lantibiotic. Unlike the plasmid-coded epidermin, gdmA is located on the chromosome. The gdmA locus codes for a 52 amino acid residue prepeptide, consisting of an alpha-helical leader sequence of hydrophilic character, which is separated from the C-terminus (propeptide) by a characteristic proteolytic processing site (Pro-2 Arg-1 Ile1). Although pro-gallidermin differs from pro-epidermin (a recently isolated lantibiotic) only by a single amino acid residue exchange. Leu instead of Ile, the N-terminus of the prepeptide differs by an additional two exchanges.