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Biomedical subjects

J D Jollick

Publications and source records attributed to J D Jollick.

14 recordsLinked to original sources
PubMed1991

A genetic transformation system for Streptococcus pyogenes.

An efficient protoplast transformation system for Streptococcus pyogenes has been developed. Efficiencies of up to 7.1 x 10(6) transformants/micrograms DNA were achieved, with transformants recovered on selective media in 24-48 h. The system was characterized as to optimal protoplasting conditions, effective facilitators, dependency on concentration of transforming DNA, plasmid copy number in transformants and stability of transformants. Three isolates of S. pyogenes were used as recipients, and four plasmids were used as the transforming DNA. Growth of S. pyogenes in glycine followed by lysozyme treatment was necessary for optimal protoplast formation. The exact concentrations of these protoplasting agents which were used varied with each isolate tested. Both polyethylene glycol and dextran sulphate were efficient facilitators of transformation, at final concentrations of 10%. An inverse relationship between DNA concentration and efficiency of transformation was shown. The copy number of the AC-1 plasmid in the transformants was shown to be equivalent to that of the wild type S. pyogenes (AC-1) (one or two copies per chromosomal equivalent). Approximately 50% of the AC-1 transformants were stable after one passage on non-selective media, and 100% of those that retained the plasmid were stable for an additional twenty generations. Erythromycin resistance encoded on the AC-1 plasmid was inducible, and transformants with a constitutive mutant of the AC-1 plasmid were detected by growth on selective media. This plasmid may prove useful as a vector as it is readily transformed, expressed, and contains at least three unique restriction sites which could serve as insertion points for cloned DNA.

Culture Media↗
PubMed1990

Clinical application of novel sample processing technology for the identification of salmonellae by using DNA probes.

Two hundred and fifty clinical fecal specimens collected over a 7-month period were analyzed for the presence of salmonellae by a rapid DNA hybridization procedure. Hybridizations were performed by using a novel specimen processing protocol called wicking and a previously unreported 1,600-base-pair probe cloned from Salmonella enteritidis DNA. The probe was shown to be reactive with all 70 Salmonella serotypes tested and not reactive with 101 stock strains of other enteric bacteria. Southern analysis of 30 Salmonella isolates representing 22 serotypes suggested that the probe sequence was highly conserved, appearing as a 1,600-base-pair band in a BglII digest of isolate DNA in 29 of 30 isolates and as a 2,300-base-pair fragment in 1 of the isolates. The probe correctly identified all salmonellae (nine isolates) among 47 H2S-producing colonies tested from among 250 clinical specimens cultured on xylose-lysine-desoxycholate medium. Salmonellae grown on xylose-lysine-desoxycholate medium gave consistently higher hybridization values than did those grown on either MacConkey or Hektoen enteric agar. In addition, of eight gram-negative broth enrichments in which salmonellae were identified by conventional means, seven were probe positive. The use of this nucleic acid probe and hybridization technique provides a simple and rapid identification of Salmonella species.

Bacteriological Techniques↗
PubMed1987

Improved DNA hybridization method for detection of acyclovir-resistant herpes simplex virus.

A simplified DNA hybridization method was developed to detect acyclovir-resistant isolates of herpes simplex virus. Herpes simplex virus-infected cell cultures in microtiter plates were treated with concentrations of acyclovir ranging from 8 to 0.015 micrograms/ml. At 48 h postinfection, infected cells were lysed by a one-step procedure and lysates were absorbed to membranes. Without further treatment, membranes were hybridized by using a herpes simplex virus-specific radioiodinated probe. The membranes were then washed and counted in a gamma counter. The elapsed time for assay performance was 4 h. Parallel plaque reduction assays were performed for comparison. The mean 50% inhibitory dose of in vivo- and in vitro-derived acyclovir-resistant, thymidine kinase-negative isolates was greater than 2 micrograms/ml by DNA hybridization. The 50% inhibitory dose of acyclovir-susceptible, thymidine kinase-positive isolates ranged from 0.01 to 1.1 micrograms/ml. This assay is simple and objective and should facilitate antiviral susceptibility testing in diagnostic laboratories.

Acyclovir↗
PubMed1981

Microinjection of a rabbit beta-globin gene into zygotes and its subsequent expression in adult mice and their offspring.

We have transferred a gene coding for rabbit beta-globin into the male pronucleus of mouse zygotes by direct microinjection. Some of these zygotes developed into mature mice which contained this gene and appeared to be producing a rabbit globin. Evidence for the presence of the gene in these animals was provided by Southern blot hybridization analysis. Evidence for the expression of the rabbit gene in these transformed mice and their offspring was provided by hemoglobin isoelectric focusing analysis and specific serological reactivity between mouse anti-rabbit hemoglobin antiserum and a hemolysate from the mice that developed from the microinjected zygotes. The use of this zygote transformation may allow the introduction and expression of a broad range of genetic elements in mammals.

Animals↗
PubMed1980

Pilus-dependent, double-stranded DNA bacteriophage for Caulobacter.

Caulobacter phage phi 6, previously reported to adsorb specifically to bacterial flagella, was shown here to attach to pili more frequently than to flagella. Phage phi 6 was shown to contain double-stranded DNA by circular dichroism spectroscopy and thermal denaturation accompanied by a hyperchromic shift at 260 nm. Morphologically, phage phi 6 fits group B2 (H.-W. Ackermann, in A. I. Laskin and H. A. Lechevalier, ed., Handbook of Microbiology, vol. 1, p. 638-643, 1973) with a long, noncontractile tail and an elongate head. Pilus-less mutants of the host Caulobacter vibrioides CV6 are phage phi 6 resistant, whereas flagellum-less mutants, which produce pili, are phage susceptible. Treatments of susceptible cells which remove or immobilize pili and flagella, e.g., blending or cyanide, inhibited phage phi 6 infection. Our evidence suggests that phage of phi 6 initiates infection in a manner similar to the pilus-specific phages for Pseudomonas described previously (D. E. Bradley, Virology 51:489-492, 1973; D. E. Bradley and T. L. Pitt, J. Gen. Virol. 24:1-15, 1974).

Bacteria↗
PubMed1977

Transfer and expression of pseudomonas plasmid RP1 in Caulobacter.

This study demonstrates that the host range of Pseudomonas plasmid RP1 includes the genus Caulobacter. Caulobacter was shown to acquire three antibiotic resistance markers located in RP1. A fourth plasmid marker, susceptibility to an RNA bacteriophage, was not expressed, but could be transferred from Caulobacter to Escherichia coli. The lack of phenotypic expression of the phage marker was manifested by the inability of the phage to adsorb or to produce plaques on Caulobacter transcipients. Matings of Pseudomonas aeruginosa and Caulobacter vibrioides CV6 were carried out in the presence of bacteriophage phi6, a DNA phage that infects and kills only swarmer cells of Caulobacter. No decrease in plasmid transfer in the presence of phage phi6 was detected, suggesting that stalked cells, and not swarmer cells, serve as recipients. Our evidence suggests that transfer of chromosomal segments from Caulobacter may be mediated by plasmid RP1; such segments are not stably maintained.

Anti-Bacterial Agents↗
PubMed1973

Nalidixic acid susceptibility testing of clinical isolates of Serratia marcescens.

Nalidixic acid (nal) susceptibility of clinical isolates of Serratia marcescens from urinary tract infections, wounds, and blood was determined by the standard disk method, and results were compared with results obtained by a standardized tube dilution procedure using five different broth media. An attempt was made to approximate in vivo conditions by using urine as a test medium and correlating the activity of nal in urine with its activity in nutrient, Trypticase soy, brain-heart infusion, and Mueller-Hinton broths. The isolates were consistently susceptible to lower concentrations of nal in nutrient broth than in the other media. The results showed that Mueller-Hinton broth most closely reflected nal activity in urine. A standardized procedure for nal susceptibility testing of urinary tract isolates of S. marcescens is proposed.

Anti-Bacterial Agents↗