In the standard procedure for artificial transformation of E. coli by plasmid DNA, cellular competence for DNA uptake is developed by suspending the cells in ice-cold CaCl2 (50-100 mM). It is believed that CaCl2 helps DNA adsorption to the lipopolysaccharide (LPS) molecules on E. coli cell surface; however, the binding mechanism is mostly obscure. In this report, we present our findings of an i...

Escherichia coli is not assumed to be naturally transformable. However, several recent reports have shown that E. coli can express modest genetic competence in certain conditions that may arise in its environment. We have shown previously that spontaneous lateral transfer of non-conjugative plasmids occurs in a colony biofilm of mixed E. coli strains (a set of a donor strain harbouring a plasmi...

The human pathogen Vibrio cholerae is an aquatic bacterium associated with zooplankton and their chitinous exoskeletons. On chitinous surfaces, V. cholerae initiates a developmental programme, known as natural competence, to mediate transformation, which is a mode of horizontal gene transfer. Competence facilitates the uptake of free DNA and recombination into the bacterial genome. Recent studi...

Purpose: Today, without having competent and efficient human resources, organizations will not be able to create transformation, development and excellence, achieve a strategic model and achieve the set goals. The way to achieve this is to develop the management and leadership of the organization and create an efficient structure for the human resources organization. Therefore, the main purpose...

Natural genetic transformation is common among many species of the genus Streptococcus, but it has never, or rarely, been reported for the Streptococcus pyogenes and S. bovis groups of species, even though many streptococcal competence genes and the competence regulators SigX, ComR, and ComS are well conserved in both groups. To explore the incidence of competence in the S. bovis group, 25 isol...

Two restriction-modification systems, S1 and S2, are present in Staphylococcus aureus RN450 (S. Iordanescu and M. Surdeanu, J. Gen. Microbiol., 96:277-281, 1976). System S2 affects phage multiplication after both infection and transfection. Unmodified plasmid and chromosomal DNAs are also not expressed following transduction and transformation into a restrictive host. Restricted phages are, how...

Agrobacterium-mediated transfer of viral sequences to plant cells (agroinfection) was applied to study the susceptibility of immature maize embryos to the pathogen. The shoot apical meristem of immature embryos 10 to 20 days after pollination from four different maize genotypes was investigated for competence for agroinfection. There was a direct correlation between different morphological stag...