GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1990-1994  (3)
  • 1
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The capacity of marine sediments to facilitate natural transformation of Pseudomonas stutzeri strain ZoBell was investigated. The role of DNA/ sediment binding on transformation frequency was also explored. While transformation frequencies increased as a function of DNA concentrations from 0 to 1.0 μg of DNA from rifampin-resistant strains for filter transformations, transformation in autoclaved sediment columns displayed a reduction in transformation frequency in response to low DNA concentrations (0–1.0 μg/cm3 sediment). Maximum transformation frequencies were obtained on filters at 1.0 μg exogenous DNA, however, maximum frequencies were not reached in sediments until a DNA concentration of 3.0 μg/cm3 sediment was added. When autoclaved sediments were pre-loaded with excess calf thymus DNA, this reduction in response of transformation frequency (cf. filter transformation) was eliminated, i.e., transformation frequencies reached saturation in the preloaded sediments at 1.0 μg DNA/cm3. Autoclaved sediments were shown to bind DNA at a concentration of about 3.6 μg/cm3 sediment, and maximum transformation frequencies were only obtained when these sediments were saturated with DNA. These data indicate that autoclaved marine sediments have the capacity to bind DNA in a form that prevents its availability for natural transformation and only after sediments are saturated with DNA does exogenous DNA become biologically active for natural transformation.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1572-9699
    Keywords: biotechnology risk assessment ; environmental gene transfer ; natural transformation ; Pseudomonas stutzeri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Both the soil isolate,Pseudomonas stutzeri JM300, and the marine isolate,Pseudomonas stutzeri strain ZoBell, have been shown previously to be naturally transformable. This study reports the detection of genetic exchange by natural transformation between these two isolates. Transformation frequency was determined by filter transformation procedures. Three independent antibiotic resistance loci were used as chromosomal markers to monitor this exchange event: resistance to rifampicin, streptomycin, and nalidixic acid. The maximum frequencies of transformation were on the order of 3.1 to 3.8×10-6 transformants per recipient; frequencies over an order of magnitude greater than those for spontaneous antibiotic resistance, although they are lower than those observed for soil: soil or marine: marine strain crosses. This exchange was inhibited by DNase I. Transformation was observed between soil and marine strains, both by filter transformation using purified DNA solutions and when transforming DNA was added in the form of viable donor cells. The results from this study support the close genetic relationship betweenP. stutzeri JM300 andP. stutzeri strain ZoBell. These results also further validate the utility ofP. stutzeri as a benchmark organism for modeling gene transfer by natural transformation in both soil and marine habitats.
    Type of Medium: Electronic Resource
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...