Glycopeptides such as vancomycin are the drugs of last resort for the treatment of severe infections caused by antibiotic resistant gram-positive bacteria. As a model strain for analysing and manipulating glycopeptide biosynthesis we have chosen Amycolatopsis balhimycina which synthesizes the vancomycin-type glycopeptide balhimycin. The 66-kb gene cluster encoding the biosynthesis of balhimycin...

Characteristically, enterohemorrhagic Escherichia coli (EHEC) strains produce Shiga-like toxin type I (SLT-I), SLT-II, or both of these immunologically distinct cytotoxins. No antigenic or receptor-binding variants of SLT-I have been identified, but a number of SLT-II-related toxins have been described. Because EHEC O91:H21 strain B2F1, which produces two SLT-II-related toxins, is exquisitely v...

Cyanobacteria (blur-green algae) are interest member of a group known as eubacteria, they are photosynthetic prokaryotes, that were originally classified as microalgae and distributed worldwide from polar to equatorial latitudes. They have very specialized cells (heterocyst, Akinetes) that are able to fix nitrogen and serve at high temperature or drought. Synthesis of toxin by many cyanobacteri...

The Ori star-forming region presents a snapshot of a moderate-mass giant molecular cloud 1{2 Myr after cloud disruption by OB stars, with the OB stars, the low-mass stellar population, remnant molecular clouds, and the dispersed gas all still present. We have used optical photometry and multi-object spectroscopy for lithium absorption to identify 266 PMS stars in 8 degrees 2 of the region. We a...

Planets have been reported orbiting the Sun-like stars 1 Cnc, Boo o, and And based on low-amplitude radial velocity variations. We have derived 1 Based on observations made at Mount Wilson Observatory, operated by the Mount Wilson Institute under an agreement with the Carnegie Institution of Washington. information on the rst two stars from analysis of spectra, as well as parallel records of hi...

We investigate time domain based electromagnetic inverse problems. This is done in the context of general polarization models (which include the familiar Debye and Lorentz models as special cases) for dielectric materials. A one-dimensional model based on time-windowed pulsed inputs is formulated and well-posedness results are given for the simulation problem. Numerical investigations of proble...

Extended Abstract In this Note I prove a representation theorem for Peirce algebras introduced in Brink, Britz and Schmidt (1994b, 1994a). I show that the class of full Peirce algebras is characterised by the class of complete and atomic Peirce algebras in which the set of relational atoms is restricted by two conditions. One requires simplicity. The other requires that each relational element ...

DNA SYNTHESIS IN CELL-FREE EXTRACTS OF A DNA POLYMERASE-DEFECTI VE MUTANT Thomas Kornberg and Malcolm L. Gefter Department of Biological Sciences Columbia University New York, New York 10027 Received August 4, 1970 Summary. A DNA-synthesizing activity has been isolated from an E. mmutant defective in DNA polvmerase. Like DNA polvmerase. the svstem requires the presence of all fbur’deoxynucleosi...

When an Frecipient Escherichia coli K12 bacterium receives Hfr or F-lac+ DNA from an ultraviolet-irradiated donor, its capacity to promote DNA repair and mutagenesis of ultraviolet-damaged phage X is substantially increased. We call this phenomenon indirect ultraviolet-reactivation, since its features are essentially the same as those of ultraviolet-reactivation; this repair process occurs in p...