The properties of donor deoxyribonucleic acid (DNA) from three clinical isolates and its ability to mediate the transformation of competent Rd strains to ampicillin resistance were examined. A quantitative technique for determining the resistance of individual Haemophilus influenzae cells to ampicillin was developed. When this technique was used, sensitive cells failed to tolerate levels of amp...

Campylobacter jejuni is a human bacterial pathogen. While poultry is considered to be a major source of food borne campylobacteriosis, C. jejuni is frequently found in the external environment, and water is another well-known source of human infections. Natural transformation is considered to be one of the main mechanisms for mediating transfer of genetic material and evolution of the organism....

Acinetobacter baylyi, a gram-negative soil bacterium, is highly competent for natural transformation, a process in which DNA is imported across cellular membranes and potentially recombined into the chromosomal genome. This study evaluated the evolutionary roles of natural competence. Two studies were performed: twitching chemotaxis and genomic repair. A chemotaxis assay was developed to invest...

The human pathogen Campylobacter jejuni is one of more than 40 naturally competent bacterial species able to import macromolecular DNA from the environment and incorporate it into their genomes. However, in C. jejuni little is known about the genes involved in this process. We used random transposon mutagenesis to identify genes that are required for the transformation of this organism. We isol...

The adaptive benefits of natural transformation, the active uptake of free DNA molecules from the environment followed by incorporation of this DNA into the genome, may be the improved response to selection resulting from increased genetic variation. Drawing analogies with sexual reproduction, transformation may be particularly beneficial when selection rapidly fluctuates during coevolution wit...

Although there are over 90 serotypes of Streptococcus pneumoniae, antimicrobial resistance is predominantly found in a limited number of serotypes/serogroups, namely 6, 9, 14, 19 and 23. There is no compelling mechanism to account for this restriction. We aimed to determine whether serotypes commonly associated with drug resistance have higher transformation frequencies than those that are susc...

PERRY, DENNIS (Northwestern University Medical School, Chicago, Ill.), AND HUTTON D. SLADE. Effects of filtrates from transformable and nontransformable streptococci on the transformation of streptococci. J. Bacteriol. 91:2216-2222. 1966.-The nature of the transformation competence factor from a group H streptococcus was investigated. The activity of competence factor reached a maximum at the t...

PERRY, DENNIS (Northwestern University Medical School, Chicago, Ill.), AND HUTTON D. SLADE. Effects of filtrates from transformable and nontransformable streptococci on the transformation of streptococci. J. Bacteriol. 91:2216-2222. 1966.-The nature of the transformation competence factor from a group H streptococcus was investigated. The activity of competence factor reached a maximum at the t...

In several bacterial species that show natural transformation, dprA has been described as a competence gene. The DprA protein has been suggested to be involved in the protection of incoming DNA. However, members of the dprA gene family (also called smf) can be detected in virtually all bacterial species, which suggests that their gene products have a more general function. We examined the funct...

Haemophilus influenzae is one of a growing number of bacteria in which the natural ability to uptake exogenous DNA for potential genomic transformation has been recognized. To date, several operons involved in transformation in this organism have been described. These operons are characterized by a conserved 22-bp regulatory element upstream of the first gene and are induced coincident with tra...