Cdc25 phosphatases

Comment on: Thomas Y, et al. Cell Cycle 2010; 9:4338–50.     

Prodigiosin-25 C

A water-insoluble red antibiotic pigment was isolated from mycelia of a strain of Streptomyces. It was found that the pigment is a new C₂₅-prodigiosin-analogue and the authors propose to designate it prodigiosin-25 C. The chemical structure (XI) has been deduced from visible absorption spectra, NMR spectra, mass spectra and analysis of degradation products of the pigment.     

Prodigiosin-25 C

The equilibrium constant of the isomerization reaction between d-glucose and d-fructose which is catalyzed by a. glucose isomerase from Streptomyces sp. was obtained by both methods of chemical analysis and of kinetic study over the temperature range of 25° to 70°C.

It was found that the formation of d-fructose from d-glucose was an endothermic reaction with the heat of the reaction, ΔH, of +2220 cal/mole. The standard free energy change, ΔG, and the standard entropy change, ΔS, associated with the isomeric change were found to be +180 cal/mole and + 6.8 cal/deg. mole at 25°C, respectively. The values of these thermodynamic quantities at other temperature are also summarized.     

25 Jahre Mykotoxin-Workshop

Mycotoxin research has a long tradition in Germany and is documented by a series of annual meetings which started 25 years ago. This paper gives an historical review on these Mycotoxin-Workshops. The first mycotoxin workshop in 1979 at the Federal Centre for Meat Research in Kulmbach was initiated by the former Federal Ministry of Agriculture and mainly thought to bring together scientists from the Federal research facilities. Main topics at that early time of mycotoxin research were food and feed safety, the mycology of toxin producers, the analysis and toxicology of mycotoxins. In the following years the Mycotoxin Workshop was influenced not only by working groups from the Federal research facilities but also from universities, state laboratories, other organisations and research scientists from outside Germany and with different disciplines. The number of participants increased from 19 at the beginning to more than 150 up to now and in order to organise these annual meetings at varying locations, in 1997 the society for mycotoxin research was founded. Since that time the Society for Mycotoxin Research (www.mykotoxin.de) is responsible for the organisation of the Mycotoxin Workshops. In addition the Society for Mycotoxin Research organizes the Brigitte Gedek science award, endowed with ￠ 10,000, and the Münchner Mycotoxin fellowship program, both intented to promote scientific research in mycotoxinology.

Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

Isolation and identification of 25-hydroxydihydrotachysterol2 1 alpha,25-dihydroxydihydrotachysterol2 and 1 beta,25-dihydroxydihydrotachysterol2

Three metabolites of orally administered dihydrotachysterol2 have been isolated in impure form from serum of rats. These metabolites have been identified as 25-hydroxydihydrotachysterol2 and two epimers of formula 1-ambo,25-dihydroxydihydrotachysterol2 by means of gas chromatography-mass spectrometry and ultraviolet absorption spectrometry. For the first time this provides evidence for 9,10-seco steroid hydroxylation at pseudo C3. The stereochemistry of the 1-hydroxyl group of the two epimers could be established tentatively by quantitative comparison of the mass spectra of their respective trimethylsilyl derivatives. Since purity requirements were not achieved, biological activities could not be determined.     

HIV-1 at 25

In 1981, the acquired immunodeficiency syndrome (AIDS) appeared insidiously and mystified doctors and scientists alike. No one could have predicted then that it would become, arguably, the worst plague in human history. Today, 33 million persons are living with infection by the human immunodeficiency virus type 1 (HIV-1), the causative agent of AIDS, while another 25 million have already died of this disease.