Tomato protoplast DNA transformation: physical linkage and recombination of exogenous DNA sequences

Tomato protoplasts have been transformed with plasmid DNA's, containing a chimeric kanamycin resistance gene and putative tomato origins of replication. A calcium phosphate-DNA mediated transformation procedure was employed in combination with either polyethylene glycol or polyvinyl alcohol. There were no indications that the tomato DNA inserts conferred autonomous replication on the plasmids. Instead, Southern blot hybridization analysis of seven kanamycin resistant calli revealed the presence of at least one kanamycin resistance locus per transformant integrated in the tomato nuclear DNA. Generally one to three truncated plasmid copies were found integrated into the tomato nuclear DNA, often physically linked to each other. For one transformant we have been able to use the bacterial ampicillin resistance marker of the vector plasmid pUC9 to 'rescue' a recombinant plasmid from the tomato genome. Analysis of the foreign sequences included in the rescued plasmid showed that integration had occurred in a non-repetitive DNA region. Calf-thymus DNA, used as a carrier in transformation procedure, was found to be covalently linked to plasmid DNA sequences in the genomic DNA of one transformant. A model is presented describing the fate of exogenously added DNA during the transformation of a plant cell. The results are discussed in reference to the possibility of isolating DNA sequences responsible for autonomous replication in tomato.

Enhancing the Phytoremediation of Hydrocarbon-Contaminated Soils in the Sudd Wetlands, South Sudan, Using Organic Manure

Phytoremediation of hydrocarbon-contaminated soils is a challenging process. In an effort to enhance phytoremediation, soil was artificially contaminated with known concentration of light crude oil containing Total petroleum hydrocarbon (TPH) at a concentration of 75 gkg−1 soil. The contaminated soil was subjected to phytoremediation trial using four plant species (Oryza longistaminata, Sorghum arundinaceum, Tithonia diversifolia, and Hyparrhenia rufa) plus no plant used as control for natural attenuation. These phytoremediators were amended with concentrations (0, 5 and 10 gkg−1 soil) of organic manure (cow dung). Results at 120 days after planting, showed that application of manure at concentrations of 5 and 10 gkg−1 soil combined with an efficient phytoremediator can significantly enhance reduction of TPH compared to natural attenuation or use of either manure or a phytoremediator alone (p0.05). Therefore, the study concludes that use of phytoremediators and manure 5 gkg−1 soil could promote the restoration of TPH contaminated-soils in the Sudd region of South Sudan

Vancomycin Prevents Polytetrafluoroethylene Graft Infections in Pediatric Patients Receiving Chronic Hemodialysis

Polytetrafluoroethylene (PTFE) grafts have been a useful addition to the pediatric hemodialysis vascular access armamentarium. In this study, 17 pediatric patients underwent 331 total months of hemodialysis via PTFE grafts. There was a statistically significant (P \u3c .025) decrease in the incidence of graft infections in 12 patients (235 patient-months) while receiving prophylactic parenteral vancomycin compared with 9 patients (96 patient-months) while receiving no vancomycin (0% v 44%). Vancomycin side effects were uncommon and mild. Vancomycin is a safe and effective agent for the prevention of PTFE graft infections in pediatric patients receiving chronic hemodialysis. © 1985, National Kidney Foundation Inc.. All rights reserved