Final report
- Dept. of Ocean, Earth, and Atmospheric Sciences, Old Dominion University
In July of 2000, we performed another field bacterial injection experiment at the DOE study site in South Oyster, Virginia. This year the injection was performed at the site named SOFA. In parallel fashion to the previous year's experiment at the NC site, we collected samples to quantify protists before and after injection of bacteria. Two bacterial strains, DA001 and iron-reducing bacterium OY107, were co-injected with a bromide tracer (100 mg per liter) into the suboxic site flow cell during a 12-hour pulse. The bacteria were marked with two different viable fluorescent stains (50% green OY107 and 50% red DA001), and the concentration of each strain in the injectate was approximately 5.0 x 10{sup 7} cells per ml. Prior to the injection, a forced gradient had been established. As the concentration of DA001 decreased following breakthrough, the predator populations increased in number (maximum concentration of 3 x 10{sup 3} protists per ml). The response of the protists was qualitatively similar to the response we observed in the previous year's experiment at the NC site. Unfortunately, post-injection coring at the SOFA site forced relocation of sampling wells and the resultant data set is less complete than for the NC site. Calculations of bacteria lost to predation are ongoing. Application of molecular tools to detect microorganisms has become increasingly important and widely adopted because of its sensitivity and specificity, both of which can be much greater than that resolved by conventional microscopy. To this end, we have endeavored to incorporate these methods into our research. First, we designed polymerase chain reaction (PCR) primers specific for flagellates by examining small subunit ribosomal DNA (SSrDNA) of more than 20 strains of flagellates. Conservative regions of base sequences were selected and primers were synthesized at Gibbco Inc. In addition, we have had additional primer sets synthesized, ones conservative for eukaryotes. Second, two species of flagellates, Spumella sp. and Bodo sp. (identifications are tentative) were isolated from South Oyster sediments by repetitive serial dilution/extinction method. Protistan cells were cultured with Cereal leaf Prescott medium and pelleted by centrifugation. Protistan DNAs were extracted with a DNA extraction kit (Sigma Co.) and the sequencing of their SSrDNA is underway. Finally, to follow up on our collaboration of Dr. Bill Johnson (Univ. of Utah), one of the co-PIs under the same NABIR umbrella, we are pleased to report we have successfully tested antibody-ferrographic capture of protists (See previous year's report for more background). Polyclonal FITC-conjugated antibody specific for a flagellate, Spumella sp., was produced by Rockland Inc., and we now are able to enumerate that species using ferrographic capture. There are, however, some issues of non-specific staining that remain to be resolved.
- Research Organization:
- Old Dominion University (US)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- FG02-99ER62821
- OSTI ID:
- 806965
- Report Number(s):
- DOE/ER62821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Change of Collision Efficiency with Distance in Bacterial Transport Experiements
Use of genetically marked minicells as a probe in measurement of predation on bacteria in aquatic environments. [Ochromonas sp. ; Escherichia coli]