Agrobacterium tumefaciens DNA and PS8 Bacteriophage DNA Not Detected in Crown Gall Tumors

Abstract

Renaturation kinetics of labeled Agrobacterium tumefaciens DNA are not influenced by addition of 104-fold excess of crown gall tumor DNA. Reconstruction experiments demonstrated that 0.01% added bacterial DNA produces a detectable increase in rate of renaturation of labeled DNA. Crown gall tumor DNA therefore cannot contain as much as 0.01% A. tumefaciens DNA, (one entire bacterial genome per three diploid tumor cells).By estimated levels range from 0.2% (6, 7) to 0.9% (8). DNA from A. tumefaciens bacteriophage PS8 has been reported present in tumor DNA at a level of 1.8% (8), despite the fact that neither viable PS8 phage nor PS8 DNA could be detected in the bacterial strain which incited the tumor examined. Unfortunately, most of these nucleic acid hybridization studies (5-7, 9) failed to include thermal dissociation profiles of the duplexes, an essential control to support the conclusion that authentic phage or bacterial nucleic acids were detected. Thermal dissociation profiles of bacterial or phage cRNA hybridized to filter-bound tumor DNA (8) have been reported (18)

Quorum Sensing but Not Autoinduction of Ti Plasmid Conjugal Transfer Requires Control by the Opine Regulon and the Antiactivator TraM

“…Bacteria were grown in Luria-Bertani broth (Gibco-BRL, Gaithersburg, Md. ), on nutrient agar plates (Difco Laboratories, Detroit, Mich.), or in AB minimal medium containing 0.2% mannitol (ABM) (5). AB medium solidified with 1.5% agar and containing 1 mM nopaline (Sigma Chemical Co., St. Louis, Mo.)…”

Phytochrome RNAi enhances major fibre quality and agronomic traits of the cotton Gossypium hirsutum L

“…Bacterial cultures were grown in culture tubes for 36 h at 26°C with shaking at 200 r.p.m. Cells from five tubes were pooled, harvested by centrifugation at 3,200 g for 10 min (Eppendorf 5810R, Germany) and resuspended in 10 ml of pre-induction medium (10 g l À 1 glucose, 14.62 g l À 1 2-(N-morpholino)ethanesulfonic acid, 20 ml l À 1 sodium phosphate buffer pH 5.6 and 50 ml l À 1 20 Â AB salt stock 34 containing 100 mM acetosyringone). For controls, 5 ml sterile water was applied instead of bacterial suspension.…”

The resistance-nodulation-division efflux pump EmhABC influences the production of 2,4-diacetylphloroglucinol in Pseudomonas fluorescens 2P24

“…The bacterial strains and plasmids used in this study are listed in Table 1. King et al, 1954) or ABM (Chilton et al, 1974) medium at 28 uC. Escherichia coli DH5a, which was used for cloning experiments, was grown in LB broth at 37 uC.…”