AIMS To establish the suitability of currently available phenotypic methods for speciation of clinical Aeromonas isolates in diagnostic microbiology laboratories. METHODS Using 62 Aeromonas spp, three schemes based on biochemical reactions were compared: a series of conventional tests; a system based on the suicide phenomenon, comprising two tubes in total; and a commercially available test, ...

In Gram-negative bacteria, envelope stress signals such as unfolded outer membrane proteins (OMP) activate the periplasmic protease DegS. This protease then triggers a cellular pathway to alleviate the stress. Now Sohn et al. (2007) show conclusively that inhibition of DegS is relieved allosterically by binding of the C-terminal sequences in unfolded OMPs to the PDZ domain of DegS.

Sources of anti-Haemophilus somnus antibody in bovine uterine secretions following intramuscular immunization and subsequent intrauterine inoculation of killed H. somnus were investigated. Holstein cattle (n = 21) were immunized with a 270-kDa outer membrane protein from H. somnus (omp-270) by intramuscular injection. At estrus, the cattle were given an intrauterine inoculum of a heat-killed su...

The aim of the present study was to evaluate the imipenem-resistant mechanism via the outer membrane protein (OMP) OprD2 and metal β-lactamase expression in the cell wall of Pseudomonas aeruginosa. The Pseudomonas aeruginosa was clinically separated and validated by VITEK-2 full-automatic bacteria analyzer. Drug resistance, sensitive antibiotics and minimum inhibitory concentration (MIC) were t...

In the E. coli periplasm, C-terminal peptides of misfolded outer-membrane porins (OMPs) bind to the PDZ domains of the trimeric DegS protease, triggering cleavage of a transmembrane regulator and transcriptional activation of stress genes. We show that an active-site DegS mutation partially bypasses the requirement for peptide activation and acts synergistically with mutations that disrupt cont...

RseA sequesters RpoE (σ(E)) to the inner membrane of Escherichia coli when envelope stress is low. Elevated envelope stress triggers RseA cleavage by the sequential action of two membrane proteases, DegS and RseP, releasing σ(E) to activate an envelope stress reducing pathway. Revertants of a ΔdegP ΔbamB strain, which fails to grow at 37°C due to high envelope stress, harbored mutations in the ...

Escherichia coli senses envelope stress using a signaling cascade initiated when DegS cleaves a transmembrane inhibitor of a transcriptional activator for response genes. Each subunit of the DegS trimer contains a protease domain and a PDZ domain. During stress, unassembled outer-membrane proteins (OMPs) accumulate in the periplasm and their C-terminal peptides activate DegS by binding to its P...

Neisseria gonorrhoeae isolated from patients with disseminated infection (DGI) often resist complement (C')-dependent killing by normal human serum (NHS) and less commonly by convalescent DGI serum. 7 of 10 NHS specimens completely inhibited killing of serum-resistant (ser(r)) gonococci by convalescent or immune DGI serum. Immunoglobulin G (IgG) purified from NHS was shown to be the blocking ag...