Anthraquinone pigments from a conidiating mutant ofTrichoderma viride

Summary Two pigments responsible for the yellow-orange color of a brown conidiating mutant of the deuteromyceteTrichoderma viride were isolated and spectroscopically identified as 1,3,6,8-tetrahydroxyanthraquinone (I) and 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthracenedione (II). Both compounds are known substances but were not yet reported as metabolites of this fungal species. Their relationship to other anthraquinones produced byT. viride is discussed.Dedicated to Dr Z. Vanek, on the occasion of his 60th birthday.Upper case letters denote multiplicity arising from the directly bonded protons, lower case letters that from the geminal and vicinal couplings.     

Experimental model for induction of lymph node metastases with a human heterotransplanted melanoma in rat

Résumé Le travail décrit une technique expérimentale qui permet d'obtenir de grosses métastases ganglionnaires chez le rat après inoculation intratesticulaire de la tumeur IOB hR 18. Ce modèle expérimental peut Être utilisé dans diverses études concernant la pathogénie et la thérapie des métastases.     

Flavonoid wing pigments in grasshoppers

Yellow pigments extracted from the hindwings ofDissoteira carolina (L.) (Acrididae:Oedipodinae) were identified by HPLC, GLC, MS and absorbance spectra as primarily quercetin and quercetin--3-O-glucoside with minor amounts of luteolin. These flavonoids make up about 2% of the hindwing live weight and are also abundant in the yellow hindwings of several related species of band-winged grasshoppers. Fat body UDPG glucosyltransferase preferentially catalyzed glucosylation of the 3-OH of quercetin.     

Suppressor of cytokine signaling 1 blocks mitosis in human melanoma cells

Hypermethylation of SOCS genes is associated with many human cancers, suggesting a role as tumor suppressors. As adaptor molecules for ubiquitin ligases, SOCS proteins modulate turnover of numerous target proteins. Few SOCS targets identified so far have a direct role in cell cycle progression; the mechanism by which SOCS regulate the cell cycle thus remains largely unknown. Here we show that SOCS1 overexpression inhibits in vitro and in vivo expansion of human melanoma cells, and that SOCS1 associates specifically with Cdh1, triggering its degradation by the proteasome. Cells therefore show a G1/S transition defect, as well as a secondary blockade in mitosis and accumulation of cells in metaphase. SOCS1 expression correlated with a reduction in cyclin D/E levels and an increase in the tumor suppressor p19, as well as the CDK inhibitor p53, explaining the G1/S transition defect. As a result of Cdh1 degradation, SOCS1-expressing cells accumulated cyclin B1 and securin, as well as apparently inactive Cdc20, in mitosis. Levels of the late mitotic Cdh1 substrate Aurora A did not change. These observations comprise a hitherto unreported mechanism of SOCS1 tumor suppression, suggesting this molecule as a candidate for the design of new therapeutic strategies for human melanoma.     

Purification of a nuclease from human serum

Summary The purification procedure for a nuclease from human serum is described. It includes ammonium sulfate precipitation, chromatography on DEAE-Sephadex and on Sephacryl-S 200, and preparative electrophoresis. The enzyme, purified about 2000-fold, is homogeneous in a sodium dodecyl sulfate electrophoretic system, where it has a mol. wt of 78,000. The pH optimum lies around pH 6.5; it is a sugar-nonspecific endonuclease.Acknowledgment. This work has been supported by a research grant from Stiftung Volkswagenwerk through the Akademie der Wissenschaften und der Literatur, Mainz. We thank Mrs R. Nehrbass and Mrs C. Wolpert for technical assistance.     

Biochemical studies of pigments from a pathogenic fungus;Microsporum cookei VI. Formation of a xanthomegnin-bypass to the mitochondrial electron transport system

Summary Enzymatic redox response of xanthomegnin was studied by means of rat liver mitochondria and the possibility of a xanthomegnin-bypass to mitochondrial electron transport system is suggested.     

Sur des pigments rouges de Levures

Summary This preliminary communication describes red, watersoluble pigments elaborated by an adeninedeficient mutant of a haploid strain of yeast (Saccharomyces cerevisi). Acid hydrolysis of these pigments liberates a number of amino acids. Some of the physical and chemical properties of these yeast pigments resemble those of the antipernicious anæmia factor (vitamin B₁₂ ¹) which contains one atom of cobalt and three atoms of phosphorus, with a molecular weight of 1,500. Our yeast pigments contain no cobalt but one or two atoms of phosphorus, with an approximate molecular weight of 2,000.A report on the biological activities of our pigments will appear in the near future.     

Indole-3-carbinol enhances ultraviolet B-induced apoptosis by sensitizing human melanoma cells

Indole-3-carbinol (I3C) has been found to act against several types of cancer, while ultraviolet B (UVB) is known to induce the apoptosis of human melanoma cells. Here, we investigated whether I3C can sensitize G361 human melanoma cells to UVB-induced apoptosis. We examined the effects of combined I3C and UVB (I3C/UVB) at various dosages. I3C (200 μM)/UVB (50 mJ/cm²) synergistically reduced melanoma cell viability, whereas I3C (200 μM) or UVB (50 mJ/cm²), separately, had little effect on cell viability. DNA fragmentation assays indicated that I3C/UVB induced apoptosis. Further results show that I3C/UVB activates caspase-8, −3, and Bid and causes the cleavage of poly(ADP-ribose) polymerase. Moreover, I3C decreased the expression of the anti-apoptotic protein, Bcl-2, whereas UVB increased the translocation of Bax to mitochondria. Thus, an increased Bax/Bcl-2 ratio by I3C/UVB may result in melanoma apoptosis. In conclusion, our study demonstrated that I3C sensitizes human melanoma cells by down-regulating Bcl-2. Received 5 July 2006; received after revision 25 August 2006; accepted 11 September 2006     

Two new pteridinic pigments inDrosophila melanogaster

Zusammenfassung Der extrahierte rote Augenfarbstoff vonDrosophila melanogaster zeigt papierchromatographisch ein Gemisch von 5 rot-orange fluoreszierenden Pterinen. Zwei von diesen bisher nicht beobachtete Stoffe treten im Puppenstadium noch nicht auf, sondern erst nach dem Ausschlüpfen der Fliegen.     

Hyperoxia and formation of chromolipoid pigments

Zusammenfassung Ratten, die wiederholt hohen O₂-Drucken ausgesetzt wurden, zeigten nach 4 Wochen erhöhte chromolipoide Pigmentation. Die Pigmentation blieb relativ gering und lag hauptsächlich in der Gefässwand und deren Umgebung bzw. den Stellen höchsten O₂-Druckes.     

Ether soluble pigments in interglacial gyttja

Zusammenfassung Etwa 100 000 Jahre alte, interglaziale Gyttja aus Rodebäk im westlichen Dänemark (Riss-Würm-Interglazialzeit) wurde mit Äther extrahiert und die Extrakte mittels Papierchromatographie getrennt und untersucht. Es wurden grüne, gelbe und rote Pigmente gefunden. Aus den Absorptionsspektren und der Fluoreszenz dieser Stoffe ergibt sich, dass die grünen Pigmente Chlorophyllderivate, die gelben (sowie wenigstens eines der roten) Karotinoide sind. Die Gyttja enthielt schr wenige bestimmbare Pflanzenreste, hauptsächlich nur Pollen und Diatomeen. Die Farbstoffe müssen von lebenden Pflanzen im interglazialen See, in erster Linie Algen, herrühren, und haben infolge Lichtabschluss und niedrigem Redoxpotential sowie niedriger Temperatur ausserordentlich gute Aufbewahrungsbedingungen gefunden; normalerweise werden solche Stoffe schnell abgebaut.     

Transplantable line of amelanotic hamster melanoma resulting from abrupt depigmentation

Zusammenfassung Im Anschluss an die plötzliche Depigmentation eines stark pigmentierten Transplantationsmelanoms des Goldhamsters wurde ein neuer pigmentloser Tumorzellstamm erhalten. Er befindet sich in seiner 39. Transplantationsgeneration. Der Tumor dieses Stammes läuft bei allen Tieren nach einer Latenzperiode von 4–5 Tagen an und führt auf Ende des ersten Monats zum Exitus. Die mikroskopische Struktur ist durch alveoläre und diffuse Anordnung von ovalen und runden, pigmentlosen Zellen und viele Mitosen charakterisiert. Zytochemisch zeigen die Tumorzellen negative DOPA-Oxydase und Tyrosinase-Reaktionen.     

DOPA decarboxylase activity in a transplantable hamster melanoma

Résumé Une activité considérable de la 3,4-dihydroxyphénylealanine (DOPA) décarboxylase a été démontrée chez un transplantable mélanome malin du hamster. Après l'injection intrapéritonéale du précurseur de la dopamine, l'amine nouveau-formée était trouvée dans toutes les tumeurs. L'inhibition de la DOPA décarboxylase par traitement des hamsters avec α-méthyle-DOPA n'a pas influé sur le progrès des tumeurs.

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This study was supported by grants from Riksf?reningen mot cancer, Stockholm, and from the Léonie Deshayes' Foundation, Lund. Melanoma-bearing Syrian hamsters were generously supplied by Prof.H. Storck, Zürich (Switzerland). The supply of α-methyl DOPA from Merck, Sharp and Dohme (USA) is gratefully acknowledged.     

Melanogenesis from tryptophan. Biogenetic experiments with harding-passey mouse melanoma

Riassunto Il triptofano¹⁴C-uniformemente marcato nell'anello benzenico e il triptofano marcato¹⁴C nel metilene sono incorporati in modo significativo nella melanina del melanoma di Harding-Passey del topo.5-ossitriptofano e 5-ossitriptamina non mostrano invece una significativa incorporazione nella stessa melanina. L'incorporazione ottenuta con il triptofano marcato sia nel nucleo che nel metilene è all'incirca uguale a quella ottenuta per somministrazione di tirosina-2-C¹⁴, per cui anche il triptofano deve essere considerato un precursore delle melanine.