An early step in the Agrobacterium-mediated transformation of Phalaenopsis violacea orchid was investigated in the plant-bacterium interaction. Directed movement in response to chemical attractants is the crucial importance to Agrobacterium tumefaciens strains. Chemotaxis of Agrobacterium tumefaciens strains (EHA 101 and 105) towards wounded orchid tissues has been studied by using swarm agar p...

ToxT, a member of the AraC family of transcriptional regulators, controls the expression of several virulence factors in Vibrio cholerae. In the classical biotype of V. cholerae, expression of toxT is regulated by the same environmental conditions that control expression of the virulence determinants cholera toxin and the toxin coregulated pilus. Several genes that activate toxT expression have...

We describe useful vectors to select double-crossover events directly in site-directed marker exchange mutagenesis in gram-negative bacteria. These vectors contain the gusA marker gene, providing colorimetric screens to identify bacteria harboring those sequences. The applicability of these vectors was shown by mapping the 3' end of the Xanthomonas campestris gum operon, involved in biosynthesi...

Fragments of the cspL promoter region were fused to the gusA reporter and reintroduced into Lactobacillus plantarum cells, either on multicopy plasmids or through single-copy chromosomal integration. beta-Glucuronidase activity and primer extension data demonstrate that the cspL promoter is induced in response to cold shock and that multicopy constructs quench the induction of the resident cspL...

Abbreviations: attE: attacin E gene ELISA: Enzyme Linked Immunosorbent Assay gusA: β-glucuronidase gene GUS: glucuronidase nos: nopaline synthase gene nptII: neomycin phosphotransferase II gene NPTII: neomycin phosphotransferase II protein PCR: polymerase chain reaction PTGS: post-transcriptional gene silencing RNA: ribonucleic acid RT-PCR: reverse transcription PCR T-DNA: transfer DNA TGS: tra...

BACKGROUND In a previous study we found that in chickweed the expression level of the pro-SmAMP2 gene was comparable or even higher to that of the β-actin gene. This high level of the gene expression has attracted our attention as an opportunity for the identification of novel strong promoters of plant origin, which could find its application in plant biotechnology. Therefore, in the present st...

A gene (htrA) coding for a stress-inducible HtrA-like protein from Lactobacillus helveticus CNRZ32 was cloned, sequenced, and characterized. The deduced amino acid sequence of the gene exhibited 30% identity with the HtrA protein from Escherichia coli; the putative catalytic triad and a PDZ domain that characterize the HtrA family of known bacterial serine proteases were also found in the seque...