Highly immunogenic regressor tumor cells can prevent development of postsurgical tumor immunity

Highly immunogenic malignant cells form small tumors that spontaneously regress after initial growth because the tumor induces specific immunity. However, variants may arise during the initial tumor growth that lose antigens, grow progressively, often become the predominant tumor population, and eventually kill the host. These progressively growing variants usually have not lost all tumor antigens and remain susceptible to rejection by T cells specific for antigens present on the parental tumor and retained by the progressively growing variants. Thus, it would seem logical for therapy to actively immunize with the parental highly immunogenic tumor (or sublines made similarly immunogenic by tumor heterogenization) after maximal surgical removal of the growing tumor. However, the present findings suggest that such a strategy may be ineffective and have adverse effects: the parental highly immunogenic tumor cells, either remaining or reintroduced, may perpetuate unresponsiveness to both the parental and the variant tumor. These findings suggest that unless tumor-induced suppression is first abrogated, immunization with highly immunogenic tumor cells may be counterproductive because this maneuver may maintain preexisting immune suppression and prevent development of postsurgical tumor immunity.     

A non-mitogenic analogue of epidermal growth factor enhances the phosphorylation of endogenous membrane proteins

The cyanogen bromide cleaved analogue of Epidermal Growth Factor (EGF) binds to EGF receptors with reduced affinity but fails to induce DNA synthesis. However, at similar receptor occupancy, cyanogen bromide cleaved EGF is as potent as EGF in enhancing the phosphorylation of endogenous membrane proteins mediated by the EGF specific, cyclic nucleotide independent protein kinase. Two possibilities arise concerning the biological role of the EGF induced membrane protein phosphorylation: 1) it is not related to the triggering of DNA synthesis by EGF and does not serve as “second messenger” for the growth factor. 2) it is a necessary but not sufficient biochemical signal for the activation of DNA synthesis by EGF.     

Analysis of gene ontology features in microarray data using the Proteome BioKnowledge Library

Microarray technology has resulted in an explosion of complex, valuable data. Integrating data analysis tools with a comprehensive underlying database would allow efficient identification of common properties among differentially regulated genes. In this study we sought to compare the utility of various databases in microarray analysis. The Proteome BioKnowledge Library (BKL), a manually curated, proteome-wide compilation of the scientific literature, was used to generate a list of Gene Ontology (GO) Biological Process (BP) terms enriched among proteins involved in cardiovascular disease. Analysis of DNA microarray data generated in a study of rat vascular smooth muscle cell responses revealed significant enrichment in a number of GO BPs that were also enriched among cardiovascular disease-related proteins. Using annotation from LocusLink and chip annotation from the Gene Expression Omnibus yielded fewer enriched cardiovascular disease-associated GO BP terms. Data sets of orthologous genes from mouse and human were generated using the BKL Retriever. Analysis of these sets focusing on BKL Disease annotation, revealed a significant association of these genes with cardiovascular disease. These results and the extensive presence of experimental evidence for BKL GO and Disease features, underscore the benefits of using this database for microarray analysis.     

Plant-microbe interactions: identification of epiphytic bacteria and their ability to alter leaf surface permeability

Bacteria were either isolated from leaf surfaces of Hedera helix or obtained from a culture collection in order to analyse their effect on barrier properties of isolated Hedera and Prunus laurocerasus cuticles. On the basis of the 16S rDNA sequences the genera of the six bacterial isolates from Hedera were identified as Pseudomonas sp., Stenotrophomonas sp. and Achromobacter. Water permeability of cuticles isolated from H. helix was measured before and after inoculation with the six bacterial strains. In addition water permeability of cuticles isolated from P. laurocerasus was measured before and after inoculation with the three bacterial strains Pseudomonas aeruginosa, Xanthomonas campestris and Corynebacterium fascians. Rates of water diffusing across isolated cuticles of both species significantly increased by up to 50% after inoculation with all bacterial strains. Obtained results show that epiphytic bacteria have the ability of increasing water permeability of Hedera and Prunus cuticles, which in turn should increase the availability of water and dissolved compounds in the phyllopshere. Consequently, living conditions in the habitat phyllosphere are improved. It can be concluded that the ability to change leaf surface properties will improve epiphytic fitness of leaf surface bacteria.     

Zur Theorie der „mitogenetischen Strahlung“

Zusammenfassung Im Anschluß an eigene Versuche wird ein kurzer kritischer Überblick über den gegenwärtigen Stand der mitogenetischen Forschung von der Detektorseite aus gegeben. Es werden die wichtigsten biologischen und physikalischen Nachweismethoden in bezug auf ihre Brauchbarkeit und Zuverlässigkeit untersucht.Bei der Zwiebelmethode muß aus neuen Versuchen Moissejewas geschlossen werden, daß die Zwiebelwurzel nicht als Detektor für die Gurwitsch-Strahlung dienen kann.Auch die Sprossungsintensität von Hefezellen kommt wegen ihrer Schwankungsbreite in der bisher geübten Art und Weise nicht als Meßinstrument für mitogenetische Strahlen in Frage.Bei Methoden, die auf einer direkten oder indirekten Bestimmung der Generationsdauer von Protisten basieren, muß zur Erlangung einwandfreier Ergebnisse ebenfalls die normale Schwankungsbreite berücksichtigt werden. Da dies bisher nicht in genügendem Maße bzw. überhaupt nicht getan wurde, muß die Richtigkeit der auf diesem Wege erhaltenen Ergebnisse bezweifelt werden.Auch mit anderen biologischen und physikalischen Methoden (Seeigeleier, Gewebekulturen, photographische Platte, Liesegangsche Ringe, lichtelektrische Erscheinungen) erhaltene Ergebnisse, die sich auf die Strahlennatur des mitogenetischen Reizfaktors beziehen, müssen teils als widerlegt, teils als in keiner Weise gesichert gelten.Es werden allgemeine Richtlienien für künftige mitogenetische Versuche aufgestellt und die Forderung erhoben, daß statt Zusammentragung weiterer nicht beweisbarer Einzelheiten zunächst die Fundamente der gesamten mitogenetischen Forschung besser und einwandfreier gesichert werden müssen. Solange dies nicht geschehen ist, liegt keine Berechtigung vor, die Gurwitsch-Strahlung als Tatsache hinzustellen.     

Untersuchungen über Parthenogenesis,Geschlechtsbestimmung und Bastardierungsvermögen bei Laminarien

Ohne ZusammenfassungMit 12 Textabbildungen.     

Sesquiterpenoids from the liverwort Lophozia ventricosa

Two sesquiterpenoids, previously reported as ventricosins A and B, from Lophozia ventricosa have been identified as ent-4(15),7(11)-eudesmadien-8-one and ent-maalioxide, respectively.