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Several versions of broad host range (BHR), L-arabinose-inducible expression vectors were constructed. These expression vectors were based on a high copy number BHR pBBR1MCS-4 replicon that could replicate in both enteric and non-enteric Gram-negative bacteria. Two versions of expression cassettes containing multiple cloning sites either with or without a(More)
Analysis of the Xanthomonas campestris pv. phaseoli (Xp) catalase profile using an activity gel revealed at least two distinct monofunctional catalase isozymes denoted Kat1 and Kat2. Kat1 was expressed throughout growth, whereas Kat2 was expressed only during the stationary phase of growth. The nucleotide sequence of a previously isolated monofunctional(More)
Xanthomonas campestris Ohr (a protein involved in organic peroxide protection) and Escherichia coli OsmC (an osmotically inducible protein of unknown function) are related proteins. Database searches and phylogenetic analyses reveal that Ohr and OsmC homologues cluster into two related subfamilies of proteins widely distributed in both Gram-negative and(More)
Burkholderia pseudomallei, an infectious Gram-negative bacterium, is the causative pathogen of melioidosis. In the present study, a B. pseudomallei strain with mutation in the bsaQ gene, encoding a structural component of the type III secretion system (T3SS), was constructed. This bsaQ mutation caused a marked decrease in secretion of BopE effector and BipD(More)
The ability of XANTHOMONAS: campestris pv. phaseoli to protect itself against lethal concentrations of man-made (N:-ethylmaleimide, NEM) and endogenously produced (methylglyoxal, MG) electrophiles was investigated. Pretreatment of X. c. pv. phaseoli with a low concentration of NEM induced protection against lethal concentrations of NEM and MG. MG(More)
Burkholderia pseudomallei, the causative agent of melioidosis, is a Gram-negative bacterium widely distributed in soil and water in endemic areas. This soil saprophyte can survive harsh environmental conditions, even in soils where herbicides (containing superoxide generators) are abundant. Sigma factor E (σE) is a key regulator of extra-cytoplasmic stress(More)
Cadmium (Cd) and zinc (Zn) are environmental pollutants affecting both soil and water. The toxicity resulting from the exposure of Xanthomonas campestris, a soil bacterium and plant pathogen, to these metals was investigated. Pretreatment of X. campestris with sub-lethal concentrations of Cd induced adaptive protection against subsequent exposure to lethal(More)
Xanthomonas showed atypical regulation of catalase (Kat) and superoxide dismutase with respect to growth phase and response to various inducers. The highest levels of both enzymes were detected during early log phase of growth and declined as growth continued. This was in contrast to resistance levels to superoxides, H2O2 and organic peroxides, which(More)
Iron is essential in numerous cellular functions. Intracellular iron homeostasis must be maintained for cell survival and protection against iron’s toxic effects. Here, we characterize the roles of Xanthomonas campestris pv. campestris (Xcc) fur, which encodes an iron sensor and a transcriptional regulator that acts in iron homeostasis, oxidative stress,(More)
Oxidant induced protection against peroxide killing was investigated in a prawn bacterial pathogen, Vibrio harveyi. Exposure to 250 microM H(2)O(2) induced adaptive protection against subsequent exposure to killing concentrations of H(2)O(2). In addition, 200 microM t-butyl hydroperoxide (tBOOH) induced cross protection to H(2)O(2) killing. On the other(More)