ABSTRACT
In a series of activities/labs, designed in a building block approach, whereas each subsequent lab builds into the next, students will explore the reactivity and production of oxygen in various biological and chemical systems. Through student-constructed analyses, participants will optimize oxygen-generating systems for the colonization of Mars, wherein their system will be used as part of a narrative to construct a livable habitat for future astronauts. Use of remote access technology to a Scanning Electron Microscope (SEM) with elemental analysis capabilities allows students to investigate their oxygen reaction via formation of iron oxide, resulting in rich multidimensional and contextualized scientific exploration in the chemistry classroom.
ABSTRACT
This communication reports the development of a TiO2-streptavidin nanoconjugate as a new biological label for X-ray bio-imaging applications; this new probe, used in conjunction with the nanogold probe, will make it possible to obtain quantitative, high-resolution information about the location of proteins using X-ray microscopy.
Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Molecular Probes/chemistry , Titanium/chemistry , Microscopy, Electron, Scanning Transmission/methods , Molecular Structure , Particle Size , Streptavidin/chemistry , X-RaysABSTRACT
The effects of four types of fullerene compounds (C60, C60-OH, C60-COOH, C60-NH2) were examined on two model microorganisms (Escherichia coli W3110 and Shewanella oneidensis MR-1). Positively charged C60-NH2 at concentrations as low as 10 mg/L inhibited growth and reduced substrate uptake for both microorganisms. Scanning electron microscopy (SEM) revealed damage to cellular structures. Neutrally charged C60 and C60-OH had mild negative effects on S. oneidensis MR-1, whereas the negatively charged C60-COOH did not affect either microorganism's growth. The effect of fullerene compounds on global metabolism was further investigated using [3-13C]L-lactate isotopic labeling, which tracks perturbations to metabolic reaction rates in bacteria by examining the change in the isotopic labeling pattern in the resulting metabolites (often amino acids).1-3 The 13C isotopomer analysis from all fullerene-exposed cultures revealed no significant differences in isotopomer distributions from unstressed cells. This result indicates that microbial central metabolism is robust to environmental stress inflicted by fullerene nanoparticles. In addition, although C60-NH2 compounds caused mechanical stress on the cell wall or membrane, both S. oneidensis MR-1 and E. coli W3110 can efficiently alleviate such stress by cell aggregation and precipitation of the toxic nanoparticles. The results presented here favor the hypothesis that fullerenes cause more membrane stress 4-6 than perturbation to energy metabolism.7.
Subject(s)
Escherichia coli/drug effects , Fullerenes/chemistry , Fullerenes/pharmacology , Nanoparticles/chemistry , Shewanella/drug effects , Carbon Isotopes , Cell Membrane/drug effects , Electrochemistry , Energy Metabolism/drug effects , Escherichia coli/metabolism , Escherichia coli/ultrastructure , Microscopy, Electron, Scanning , Nanoparticles/ultrastructure , Shewanella/metabolism , Shewanella/ultrastructureABSTRACT
The first fullerene (C60) immunoconjugates have been prepared and characterized as an initial step toward the development of fullerene immunotherapy (FIT).
