Mechanisms of recombination and function of DNA in bacteria. Progress report, August 16, 1979 to August 15, 1980

Major effort in this period has gone to (1) analysis of the process of plasmid transformation in pneumococcus, (2) continued study of resistance determinants inserted in the chromosomes of clinical strains of pneumococcus and their transfer by conjugation, a novel phenomenon, discovered last year, and (3) temperate phages of pneumococcus

Alkaline phosphatase inhibits cloning in Streptococcus pneumoniae.

Use of alkaline phosphatase to treat linearized vector DNAs inhibits recovery of recombinant plasmids during cloning in Streptococcus pneumoniae. Our understanding of the entry process leads us to expect this result for cloning in naturally competent Gram-positive bacteria, in which single-stranded segments of donor DNA enter after being cut on the surface of the cell

Cloning and physical characterization of chromosomal conjugative elements in streptococci.

We used a directed insertion method to introduce a nonreplicating vector plasmid into the large conjugative cat-tet element found in the chromosome of Streptococcus pneumoniae BM6001 and derivatives. To direct insertion preferentially to the conjugative element, we transferred it by conjugation to Streptococcus faecalis and then used DNA from this strain as a source of restriction nuclease fragments for ligation to digests of the vector pVA891, which can replicate in Escherichia coli but not in streptococci. This ligation mix was used to transform pneumococcal cells carrying the cat-tet element, with selection for the erythromycin resistance carried by pVA891. Eight such isolates were found, and transformation and conjugation tests showed that in each case the vector had inserted into the conjugative element, as expected. DNA from these pneumococcal strains generated a variety of E. coli plasmids which provide tools for obtaining a detailed restriction map and for defining other structural features of the streptococcal conjugative element

Rights and controls in the management of migration: the case of Germany

In May 1999 Germany took a significant step away from its reliance on blood based belonging, revising its nationality law to introduce an element of territory (jus soli) in the designation of citizenship. This paper offers Germany as a case study in the management of migration through a hierarchical system for the granting of rights, and considers the likely impact of the new law on the legal structures of inclusion and exclusion. It is argued that alongside the enhanced recognition of the original guestworker population a set of contradictory pressures now dominate the politics of migration ? the recognition of human rights, the management of the labour market and the protection of welfare resources. These pressures are mediated by the granting and withholding of rights as part of a system of selection, surveillance, deterrence and control which has broader implications for our thinking about citizenship