Studies on Transformations of <i>Hemophilus influenzae  </i>

Goodgal, Sol H.; Herriott, Roger M.

doi:10.1085/jgp.44.6.1229

Cited by 15 publications

(5 citation statements)

References 9 publications

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“…This gonococcal isolate carries a gene, mtr, giving increased resistance to a variety of antibacterial agents, and also a small number of genes giving increased resistance to a particular type of antibiotic (e.g., the penicillins). In preliminary experiments, similar results were obtained using DNA extracted from four other multiple- (6,12). The technique which we used to extract DNA was not designed to preserve high-molecular-weight DNA (13).…”

Section: Discussionsupporting

confidence: 53%

Genetic Analysis of Drug Resistance in Neisseria gonorrhoeae : Identification and Linkage Relationships of Loci Controlling Drug Resistance

Maier

Zubrzycki

Coyle

1975

Antimicrob Agents Chemother

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The genetic basis of multiple drug resistance of Neisseria gonorrhoeae was investigated by the technique of transformation. Six different genetic loci were characterized by the type and amount of antibiotic resistance they controlled, and also by the degree of linkage to other resistance markers. A streptomycin resistance locus is linked to separate loci determining resistance to tetracycline, chloramphenicol, and erythromycin. A multiple resistance locus was identified. This genetic locus determines resistance to a variety of antibacterial agents. Lastly, a locus determining resistance to the penicillins was found which is unlinked to any other resistance locus.The emergence of gonococci with increased drug resistance has rendered many antibiotics ineffective or barely effective in the treatment of gonorrheae (17,20). With growing frequency, multiply drug-resistant strains are encountered which exhibit increased resistance to penicillin, tetracycline, and streptomycin, as well as to other antimicrobial agents (10,11,15).We have undertaken studies to investigate the genetic basis of multiple drug resistance in naturally occurring strains of Neisseria gonorrhoeae. It was possible to analyze antibiotic resistance using transformation, since the gonococcus has been shown previously to be a competent species (16 Media and cultivation of gonococci. GC agar consisting of GC medium base (Difco), and 1.0% chemically defined supplements 1 and 2 (17) were used for routine culturing of gonococci and as the base medium when antibiotics were incorporated. The GC broth used in these experiments was prepared following the formula of GC medium base with the omission of starch and agar. Gonococci were incubated at 36 C under 5% CO2 in a CO2 incubator.MIC technique. The minimal inhibitory concentration (MIC) of a gonococcal isolate was determined by an agar dilution technique. Gonococci to be tested were streaked twice for isolation on GC agar. Colonies (18 to 24 h) were suspended in GC broth, vortexed vigorously, and diluted to contain approximately 5 x 107 colony-forming units (CFU) per ml, as judged against a borium sulfate turbidity standard. The desired concentrations of antibiotic were incorporated into 20 ml of GC agar in a 100-mm Petri dish.

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Section: Discussionsupporting

confidence: 53%

Genetic Analysis of Drug Resistance in Neisseria gonorrhoeae : Identification and Linkage Relationships of Loci Controlling Drug Resistance

Maier

Zubrzycki

Coyle

1975

Antimicrob Agents Chemother

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“…Figure 2A shows the rate for all three reactions at four different temperatures. Cells and T7 bacteriophage DNA were incubated for 10 min, centrifuged (7,500 x g, 10 min, 0 to 4°C), and processed as described in Materials and Methods. Figure 2B shows the corresponding Arrhenius plots.…”

Section: Resultsmentioning

confidence: 99%

“…Young and Spizizen (46) observed an optimum between 34 and 370C for B. subtilis cells. Goodgal and Herriott (7) reported an optimum of 340C for transformation in H. influenzae cells. S. sanguis WE4 cells had an optimum temperature of 300C for DNase-resistant DNA binding, similar to pneumococci.…”

Section: Ranhandmentioning

confidence: 99%

Interactions of competent Streptococcus sanguis (Wicky) cells with native or denatured, homologous or heterologous deoxyribonucleic acids

Ranhand¹

1980

J Bacteriol

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Competent cell-deoxyribonucleic acid (DNA) interactions were examined using tritium-labeled homologous or heterologous native or denatured DNAs and competent Streptococcus sanguis Wicky cells (strain WE4). The DNAs used were extracted from WE4 cells, Escherichia coli B cells, and E. coli bacteriophages T2, T4, T6, and T7. The reactions examined were: (i) total DNA binding, (ii) deoxyribonuclease-resistant DNA binding, and (iii) the production of acidsoluble products from the DNA. Optimal temperatures for the reactions were as follows: reaction (i), between 30 and 40°C; reaction (ii), 30°C; and reaction (iii), greater than 400C. The rates for the reactions (expressed as molecules of DNA that reacted per minute per colony-forming unit) did not vary greatly from one DNA source to another. With a constant competent cell concentration and differing DNA concentrations below a saturation level (from a given source), a different but constant fraction of the added DNA was cell bound, deoxyribonuclease resistant, and degraded to acid-soluble products. In experiments where the number of competent cells was varied and the DNA concentration was held constant, again essentially the same result was obtained. The extent of reactions (i), (ii), and (iii) depended upon the numbers as well as the source of DNA molecules applied to competent cells. Calcium ion essential for native DNA-cell reactions was also found essential for denatured DNA-cell reactions. Data obtained from competition experiments lead to the conclusion that competent WE4 cells contain specific sites for native as well as denatured DNAs.The complex competent cell-DNA reaction has been studied by a number of investigators using competent cells from different genera (

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“…A semiquantitative method using whole‐cell multiplex PCR has been described to distinguish the competence ability of various V. cholerae mutants (Suckow et al., ). Another approach described for Haemophilus influenzae uses natural transformation to numerically capture the percent fraction of competent cells (Goodgal and Herriott, ). As Vibrio cholerae cells can also incorporate unlinked mutations through cotransformation (Dalia et al., ), by estimating the transformation frequency of single and cotransformation events, it is also possible to calculate the fraction of competent cells obtained under a given set of conditions for V. cholerae strains.…”

Section: Commentarymentioning

confidence: 99%

Vibrio cholerae: Measuring Natural Transformation Frequency

2014

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Many bacteria can become naturally competent to take up extracellular DNA across their outer and inner membranes by a dedicated competence apparatus. Whereas some studies show that the DNA delivered to the cytoplasm may be used for genome repair or for nutrition, it can also be recombined onto the chromosome by homologous recombination: a process called natural transformation. Along with conjugation and transduction, natural transformation represents a mechanism for horizontal transfer of genetic material, e.g., antibiotic resistance genes, which can confer new beneficial characteristics onto the recipient bacteria. Described here are protocols for quantifying the frequency of transformation for the human pathogen Vibrio cholerae, one of several Vibrio species recently shown to be capable of natural transformation. © 2014 by John Wiley & Sons, Inc.

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Studies on Transformations of Hemophilus influenzae

Cited by 15 publications

References 9 publications

Genetic Analysis of Drug Resistance in Neisseria gonorrhoeae : Identification and Linkage Relationships of Loci Controlling Drug Resistance

Genetic Analysis of Drug Resistance in Neisseria gonorrhoeae : Identification and Linkage Relationships of Loci Controlling Drug Resistance

Interactions of competent Streptococcus sanguis (Wicky) cells with native or denatured, homologous or heterologous deoxyribonucleic acids

Vibrio cholerae: Measuring Natural Transformation Frequency

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