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Bacteriophages have developed multiple host cell lysis strategies to promote release of descendant virions from infected bacteria. This review is focused on the lysis mechanisms employed by tailed double-stranded DNA bacteriophages, where new developments have recently emerged. These phages seem to use a least common denominator to induce lysis, the(More)
The minimal inhibitory concentrations of antituberculosis and antileprosy drugs were determined for Mycobacterium aurum. The concentrations that reduced the final yield of bacteriophage D29R1 by 50% and the time during the replication cycle at which the drugs completely inhibited phage production were estimated. THe 50% inhibitory concentration/minimal(More)
Pathogenic mycobacteria such as Mycobacterium tuberculosis and Mycobacterium avium facilitate disease by surviving intracellularly within a potentially hostile environment: the macrophage phagosome. They inhibit phagosome maturation processes, including fusion with lysosomes, acidification and, as shown here, membrane actin assembly. An in vitro assay(More)
Cell surface receptors exploited by human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) for infection are major determinants of tropism. HIV-1 usually requires two receptors to infect cells. Gp120 on HIV-1 virions binds CD4 on the cell surface, triggering conformational rearrangements that create or expose a binding site for a(More)
In vivo, human immunodeficiency virus type 2 (HIV-2) infection reveals several unique characteristics when compared to HIV-1 infection, the most remarkable of which is the extraordinarily long asymptomatic period. Here we describe two HIV-2 primary isolates, obtained from asymptomatic individuals, which do not infect any coreceptor-expressing cell lines(More)
The rpoB gene mutations in a 69-bp region of the gene, resulting in resistance to rifampin, were used to discriminate between Mycobacterium tuberculosis IS6110 fingerprint subclusters. These subclusters exhibited identical IS6110 fragments or had one or two additional fragments. In the two major subclusters all the analyzed strains have the same variant(More)
SETTING Multidrug-resistant tuberculosis (MDR-TB) mainly among human immunodeficiency virus (HIV) seropositive patients in Lisbon hospitals in 1996-1997. OBJECTIVE Detection of transmission of MDR-TB strains and epidemic outbreaks in several hospital units in the city of Lisbon, including a prison hospital. DESIGN Use of restriction fragment length(More)
We have previously shown the existence of primary human immunodeficiency virus type 2 isolates (MIC97 and MJC97) unable to use major coreceptors to entry into peripheral blood mononuclear cells, including CCR5 and CXCR4. We have now created a set of chimeric viruses derived from HIV-2(ROD), to study the contribution of env gene products in chemokine(More)
Genetic determinants of the temperate mycobacteriophage Ms6 required for chromosomal integration were identified. DNA sequence analysis of an attP-containing fragment revealed an ORF encoding a protein of 372 amino acid residues with a C-terminus similar to other conserved C-terminal regions typical of the phage integrase family. Comparison of the sequences(More)
Human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) are the causative agents of Acquired Immunodeficiency Syndrome (AIDS). Without therapeutic intervention, HIV-1 or HIV-2 infections in humans are characterized by a gradual and irreversible immunologic failure that ultimately leads to the onset of a severe immunodeficiency that constitutes the(More)