Nick R. Konkol

NOVEL METHOD OF MICRONUTRIENT APPLICATION INCREASES RADISH (RAPHANUS SATIVUS) AND SHIRONA (BRASSICA RAPA VAR. PEKINENSIS) BIOMASS

The practice of enriching nutrient-poor soils with large quantities of chemical fertilizer has contributed significantly to the boost in agricultural productivity witnessed over the last century. Plants also require minute quantities of micronutrients, such as iron (Fe), manganese (Mn), and zinc (Zn). Inadequate micronutrient concentrations in the soil are a crucial problem for crop production that can severely reduce yield and nutritional quality of crops. Modern agriculture can further promote micronutrient deficiency through excessive irrigation and imbalanced application of chemical fertilizers. Anecdotal evidence suggested that irrigation of crops with FFC H2O, a commercial product currently utilized by the agriculture, fishery, and food industries in Japan, improved crop yields. Our study quantified the biomass of radish and shirona plants watered with FFC H2O. These plants developed larger leaves, greater dry weight, and longer stems than plants watered with deionized H2O. Inductively coupled plasma mass spectroscopy revealed the presence of several biologically relevant micronutrients in FFC H2O. Radish plants watered with an FFC H2O solution that lacked micronutrients, or nutrient solutions that lacked either iron or zinc failed to increase plant size relative to controls. These results provide quantitative evidence that FFC H2O operates via micronutrient supplementation, and may alleviate micronutrient deficiencies through the addition of critical elements such as Fe and Zn. FFC H2O offers agriculturalists a simple and effective tool for the fortification of irrigation waters with micronutrients.

The use of force-volume microscopy to examine bacterial attachment to titanium surfaces

Force-volume microscopy (FVM) was used to study the interfacial and adhesive forces affecting primary bacterial attachment to surfaces. Forces were measured for titanium surfaces immersed either in cation-enriched (CE) solutions of yeast extract amended with phosphate buffer or in control solutions lacking the cation enrichment. The FVM measurements demonstrated that regions of elevated interfacial repulsion covered 72(±2)% of the surfaces immersed in CE solutions, compared to 26(±2)% for immersion in control solutions. Parallel collection of scanning electron micrographs demonstrated that surface densities of attached Pseudomonas aeruginosa were approximately 0.62(±1.3) × 106 cells cm−2 compared to 8.7(±0.8) × 106 cells cm−2 for surfaces immersed in the CE and control solutions, respectively. Interfacial repulsion indicated by FVM measurements therefore served as a predictor of bacterial attachment. Another factor influencing bacterial attachment was the adhesion force. FVM measurements indicated that the upper fifth percentile of surface adhesion was 1784(±40) pN for surfaces immersed in the CE solution compared to 2284(±40) pN for the control solutions. The more extensive regions of elevated interfacial repulsion as well as of decreased surface adhesion provide an explanation for the lower density of attached cells observed for the surfaces immersed in the CE compared to the control solutions. The conclusion is that FVM is a sensitive and informative technique that can be used to measure and explain interactions between microorganisms and surfaces.

Characterization of Filamentous Accretions On Daguerreotype Surfaces

Abstract Daguerreotypes were a popular method of photography since their introduction in 1839 until their eventual demise ca. 1860. A silver mercury amalgam deposited on a polished silver surface captured many unique images of individuals, landscapes, and the natural world. Daguerreotypes that have survived to the present day exhibit many unique patterns of deterioration and are susceptible to damage. The appearance of fibril accretions on improperly stored daguerreotypes is a common symptom of deterioration. Initial investigations based on morphologic observations of these fibrils concluded that the structures were fungi encrusted with silicon and smaller amounts of other chemicals. Later work proposed that these accretions were strictly chemical in nature. Gross microscopic observation of the fibrous accretions present on several daguerreotypes examined at Harvard University suggested that these structures were fungal in origin. This study used traditional culture techniques and nonculture molecular methods to isolate viable fungal organisms from the face of a daguerreotype and detect fungal nucleic acids. Additional microscopic and energy-dispersive x-ray spectroscopy analyses were performed to further characterize the fibrous accretions. The data demonstrates that some fibril accretions are due to fungal contamination of the daguerreotype surface.