The influence of estradiol on the distribution of exogenous cholesterol-4-C14 in the rat

Zusammenfassung Vorbehandlung mit Östradiolbenzoat führte bei kastrierten männlichen Ratten zu einer verminderten Aufnahme von oral zugeführtem Cholesterin-4-C¹⁴ in die Aorta. Bei kastrierten wie auch bei intakten Tieren war nach Östrogenbehandlung die Aufnahme von markiertem Cholesterin in die Leber erhöht. Durch Analyse der Faeces liess sich nachweisen, dass Östrogenbehandlung sowie Kastration die Sterolausscheidung beschleunigt.     

Longevity,hepatic lipid peroxidation and hepatic fatty acid composition of mice fed saturated or unsaturated fat-supplemented diets

Zusammenfassung Mäuse, die während des ganzen Lebens Nahrung mit 15% Safblumenöl aufnahmen, zeigten eine Steigerung des Linolsäuregehaltes der Leber. Dieses Futter blieb ohne Wirkung auf die Höhe der Oxydations-produkte, Gewichtskurven oder Langlebigkeit der Versuchstiere, dies im Gegensatz zu Mäusen, die im Futter 15% gehärtetes Kokosnussöl oder kein zusätzliches Fett bekamen.

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This investigation was supported by Grant No. P-364 from the American Cancer Society.     

Rhetorical Strategy in Forensic Speeches: Multidimensional Statistics-Based Methodology

Rhetorical strategy is relevant in the law domain, where language is a vital instrument. Textual statistics have much to offer for uncovering such a strategy. We propose a methodology that starts from a non-structured text; first, the breakpoints are automatically detected and lexically homogeneous parts are identified; then, the shape of the text through the trajectory of these parts and their hierarchical structure are uncovered; finally, the argument flow is tracked along. Several methods are combined. Chronological clustering of multidimensional count series detects the breakpoints; the shape of the text is revealed by applying correspondence analysis to the parts×words table while the progression of the argument is described by labelled time-constrained hierarchical clustering. This methodology is illustrated on a rhetoric forensic application, concretely a closing speech delivered by a prosecutor at Barcelona Criminal Court. This approach could also be useful in politics, communication and professional writing.     

Visualizing transient events in amino-terminal autoprocessing of HIV-1 protease

HIV-1 protease processes the Gag and Gag-Pol polyproteins into mature structural and functional proteins, including itself, and is therefore indispensable for viral maturation. The mature protease is active only as a dimer with each subunit contributing catalytic residues. The full-length transframe region protease precursor appears to be monomeric yet undergoes maturation via intramolecular cleavage of a putative precursor dimer, concomitant with the appearance of mature-like catalytic activity. How such intramolecular cleavage can occur when the amino and carboxy termini of the mature protease are part of an intersubunit beta-sheet located distal from the active site is unclear. Here we visualize the early events in N-terminal autoprocessing using an inactive mini-precursor with a four-residue N-terminal extension that mimics the transframe region protease precursor. Using paramagnetic relaxation enhancement, a technique that is exquisitely sensitive to the presence of minor species, we show that the mini-precursor forms highly transient, lowly populated (3-5%) dimeric encounter complexes that involve the mature dimer interface but occupy a wide range of subunit orientations relative to the mature dimer. Furthermore, the occupancy of the mature dimer configuration constitutes a very small fraction of the self-associated species (accounting for the very low enzymatic activity of the protease precursor), and the N-terminal extension makes transient intra- and intersubunit contacts with the substrate binding site and is therefore available for autocleavage when the correct dimer orientation is sampled within the encounter complex ensemble.     

Modulation of antibody synthesis by an anti-tumour alga

Summary An unicellular alga,Chlorella pyrenoidosa, which had been reported to protect C₃H mice against sarcoma BP8, is shown, when injected in Freund's incomplete adjuvant, to modulate the antibody synthesis induced by immunization with a hapten-carrier complex.C. pyrenoidosa appeared to be able to initiate an antigenic competition between hapten and carrier determinants of the antigen molecule during antibody synthesis, and thus it could be speculated thatC. pyrenoidosa modulates the immune response at the macrophage level.Acknowledgments. This work was supported by the Secrétariat d'Etat aux Universités and by the DGRST, grant No. 77.71347.     

Ancient co-speciation of simian foamy viruses and primates

Although parasite-host co-speciation is a long-held hypothesis, convincing evidence for long-term co-speciation remains elusive, largely because of small numbers of hosts and parasites studied and uncertainty over rates of evolutionary change. Co-speciation is especially rare in RNA viruses, in which cross-species transfer is the dominant mode of evolution. Simian foamy viruses (SFVs) are ubiquitous, non-pathogenic retroviruses that infect all primates. Here we test the co-speciation hypothesis in SFVs and their primate hosts by comparing the phylogenies of SFV polymerase and mitochondrial cytochrome oxidase subunit II from African and Asian monkeys and apes. The phylogenetic trees were remarkably congruent in both branching order and divergence times, strongly supporting co-speciation. Molecular clock calibrations revealed an extremely low rate of SFV evolution, 1.7 x 10(-8) substitutions per site per year, making it the slowest-evolving RNA virus documented so far. These results indicate that SFVs might have co-speciated with Old World primates for at least 30 million years, making them the oldest known vertebrate RNA viruses.