Open AccessSurvival of κ‐carrageenan‐encapsulated and unencapsulated Pseudomonas aeruginosa UG2Lr cells in forest soil monitored by polymerase chain reaction and spread plating
Author(s) -
Leung Kamtin,
Cassidy Michael B.,
Holmes Steve B.,
Lee Hung,
Trevors Jack T.
Publication year - 1995
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.1995.tb00270.x
Subject(s) - biology , population , polymerase chain reaction , microbiology and biotechnology , pseudomonadaceae , soil test , pseudomonas , bacteria , dry weight , soil water , incubation , extraction (chemistry) , pseudomonas aeruginosa , veterinary medicine , food science , horticulture , chromatography , biochemistry , chemistry , ecology , medicine , genetics , demography , sociology , gene
A method was developed for direct extraction, purification and amplification of DNA from forest soil. Eighty‐two % of the DNA in Pseudomonas aeruginosa UG2Lr introduced into soil was recovered. The detection limit for the strain was approximately 800 cfu g −1 of dry soil based on the polymerase chain reaction (PCR). Survival of κ‐carrageenan‐encapsulated and unencapsulated UG2Lr was monitored by antibiotic selective and bioluminescence‐based nonselective plating and PCR‐amplification of a tnsA fragment. After freeze‐thaw treatment of soil samples, the unencapsulated UG2Lr declined from an initial population density of 1 × 10 9 cfu g −1 of dry soil to below the detection threshold of both selective (14 cfu g −1 of dry soil) and nonselective (1 × 10 3 cfu g −1 of dry soil) plating. However, presence of nonculturable UG2Lr cells in the soil was revealed by PCR and resuscitation of the bacteria. Population density of the encapsulated UG2Lr increased from 2.7 × 10 6 to 2.9 × 10 8 cfu g −1 of dry soil after a 3‐week incubation at 22°C and declined to 6.3 × 10 6 cfu g −1 of dry soil after the freeze‐thaw treatment.