Enumerating low densities of genetically engineered Erwinia carotovora in soil.
An inexpensive, quantitative, and sensitive technique was developed for detection of genetically engineered Erwinia carotovora in soil samples. Enrichment media, antibiotic resistance, and most probable number (MPN) analysis were used to enumerate as few as 1 to 10 target cells/10 g soil. The MPN technique recovered significantly higher cell densities than plating; however, densities estimated by the two techniques were strongly correlated. After inoculation of soil microcosms with genetically engineered E. carotovora, a decline rate of 1.2 log units/g soil/10 days and then subsequent disappearance was observed using the MPN technique.
Abstrcat Taking a sand-grown plant garden for example, the garden's natural conditions and land use actuality are analyzed, and the landscape ecological construction goal of the garden is proposed. A study is conducted on the ecological design of the garden landscape.