High temporal variability of zooplankton,but only weak evidence for a near-bottom effect on composition and distribution in the deep Levantine Basin,eastern Mediterranean

Abundance and composition of the near-bottom zooplankton between 10 and 100 metres above the bottom (mab) were studied in the Levantine Basin, eastern Mediterranean, during four cruises of RV Meteor in June 1993, January 1998, April/May 1999 and October 2001. Copepoda made up 91% of all zooplankton caught. A strong dominance of one single species was observed on all cruises, with Lucicutia longiserrata reaching 50–90% of all Copepoda except in 1993, when Subeucalanus monachus was the most abundant species, with more than 90% of all Copepoda. The year 1993 was also exceptional in terms of total zooplankton abundance, being more than one order of magnitude higher than in the other years. Vertical differences in abundance and composition were small and did not indicate a near-bottom effect or a specialized benthopelagic zooplankton community in the layers sampled.     

In vivo neutralization of TNF-alpha promotes humoral autoimmunity by preventing the induction of CTL.

Neutralization of TNF-alpha in humans with rheumatoid arthritis or Crohn's disease has been associated with the development of humoral autoimmunity. To determine the effect of TNF-alpha neutralization on cell-mediated and humoral-mediated responses, we administered anti-TNF-alpha mAb to mice undergoing acute graft-vs-host disease (GVHD) using the parent-into-F(1) model. In vivo neutralization of TNF-alpha blocked the lymphocytopenic features characteristic of acute GVHD and induced a lupus-like chronic GVHD phenotype (lymphoproliferation and autoantibody production). These effects resulted from complete inhibition of detectable antihost CTL activity and required the presence of anti-TNF-alpha mAb for the first 4 days after parental cell transfer, indicating that TNF-alpha plays a critical role in the induction of CTL. Moreover, an in vivo blockade of TNF-alpha preferentially inhibited the production of IFN-gamma and blocked IFN-gamma-dependent up-regulation of Fas; however, cytokines such as IL-10, IL-6, or IL-4 were not inhibited. These results suggest that a therapeutic TNF-alpha blockade may promote humoral autoimmunity by selectively inhibiting the induction of a CTL response that would normally suppress autoreactive B cells.     

Hemmwirkungen von Pflanzenpreßsäften auf das Tetrazolreduktionsvermögen von Bacterium coli

Zusammenfassung In Anlehnung an frühere Untersuchungen von Wallhäusser u. Rippel-Baldes, in denen sich die Brauchbarkeit des Schnelltestes mit Triphenyltetrazoliumchlorid zur Wertbestimmung von Antibiotica und Desinfektionsmitteln ergab, wurde versucht, mit Hilfe dieses testes einen Einblick in das hemmstoffbedingte Abwehrvermögen höherer Pflanzen gegenüber Mikroorganismen zu gewinnen. Bacterium coli und einige weitere vergleichsweise untersuchte Bakterienarten ließen nach Einwirkung frischer Preßsäfte aus den Blättern verschiedener Pflanzenarten stets eine deutliche — meistens sogar eine tatale — Hemmung ihres TTC-Reduktionsvermögens erkennen.Das Ausmaß der Hemmwirkung der einzelnen Preßsäfte wies erhebliche Unterschiede auf; eine totale Hemmung der mikrobiellen Formazanbildung bewirkten einige Preßsäfte noch in einer Verdünnung von 1/32, eine partielle Hemmung äußerstenfalls noch in einer Verdünnung von 1/128.Die besondere Eignung des Tetrazoltestes zur Untersuchung pflanzlicher Hemmstoffwirkungen auf Mikroorganismen ergibt sich einerseits aus seiner einfachen Handhabung, da er ein Arbeiten mit nichtsterilen Pflanzenpreßsäften gestattet, und andererseits aus der Tatsache, daß er bereits in kürzester Zeit zu Ergebnissen führt; infolgedessen lassen sich Wirksamkeitsveränderungen der Hemmstoffe, die bei anderen Testmethoden während der Bebrütung gegebenenfalls eintreten können, weitgehend vermeiden.     

Biotransformation of 2,2-Dimethyl-1,3-Propanediol to 3-Hydroxypivalic Acid by Acetobacter Acetii DSMZ3508 and Related Bacteria

Acetobacter acetii DSMZ3508 and related bacteria converted 2,2-dimethyl-1,3-propanediol into 3-hydroxypivalic acid (2,2-dimethyl-3-hydroxypropionic acid; 3HP) during submerged cultivation in mineral salt medium. The maximum yield of 3-hydroxypivalic acid was 24.4% of the fed substrate after 18 days. Cultivation parameters, as pH, cell density, optimal substrate concentration, and oxygen supply for the bioconversion process were determined.