Characterization and source apportionment of organic aerosol using offline aerosol mass spectrometry

Field deployments of the Aerodyne Aerosol Mass Spectrometer (AMS) have significantly advanced real-time measurements and source apportionment of non-refractory particulate matter. However, the cost and complex maintenance requirements of the AMS make its deployment at sufficient sites to determine regional characteristics impractical. Furthermore, the negligible transmission efficiency of the AMS inlet for supermicron particles significantly limits the characterization of their chemical nature and contributing sources. In this study, we utilize the AMS to characterize the water-soluble organic fingerprint of ambient particles collected onto conventional quartz filters, which are routinely sampled at many air quality sites. The method was applied to 256 particulate matter (PM) filter samples (PM1, PM2:5, and PM10, i.e., PM with aerodynamic diameters smaller than 1, 2.5, and 10 μm, respectively), collected at 16 urban and rural sites during summer and winter. We show that the results obtained by the present technique compare well with those from co-located online measurements, e.g., AMS or Aerosol Chemical Speciation Monitor (ACSM). The bulk recoveries of organic aerosol (60–91 %) achieved using this technique, together with low detection limits (0.8 μg of organic aerosol on the analyzed filter fraction) allow its application to environmental samples. We will discuss the recovery variability of individual hydrocarbon ions, ions containing oxygen, and other ions. The performance of such data in source apportionment is assessed in comparison to ACSM data. Recoveries of organic components related to different sources as traffic, wood burning, and secondary organic aerosol are presented. This technique, while subjected to the limitations inherent to filter-based measurements (e.g., filter artifacts and limited time resolution) may be used to enhance the AMS capabilities in measuring size-fractionated, spatially resolved longterm data sets.

Global pulses of organic carbon burial in deep-sea sediments during glacial maxima

The burial of organic carbon in marine sediments removes carbon dioxide from the ocean–atmosphere pool, provides energy to the deep biosphere, and on geological timescales drives the oxygenation of the atmosphere. Here we quantify natural variations in the burial of organic carbon in deep-sea sediments over the last glacial cycle. Using a new data compilation of hundreds of sediment cores, we show that the accumulation rate of organic carbon in the deep sea was consistently higher (50%) during glacial maxima than during interglacials. The spatial pattern and temporal progression of the changes suggest that enhanced nutrient supply to parts of the surface ocean contributed to the glacial burial pulses, with likely additional contributions from more efficient transfer of organic matter to the deep sea and better preservation of organic matter due to reduced oxygen exposure. These results demonstrate a pronounced climate sensitivity for this global carbon cycle sink.

Role of organic cation transporters in the renal secretion of nucleoside analogs

The mammalian kidney maintains homeostasis of the extracellular environment and eliminates toxic substances from the body, in part via secretion by the organic cation transporters (OCT). Some nucleosides are also secreted by the kidney. Previous work indicated that the deoxyadenosine analog, 2′ -deoxytubercidin (dTub), is secreted by mouse kidney through the OCTs. This study examines the role of OCTs in the renal secretion of dTub and other nucleoside analogs. ^ Using the Xenopus laevis oocyte expression system, the basolateral type rat organic cation transporter rOCT1 was shown to transport dTub and other nucleosides. The positive charged form of dTub (dTub +) appears to be the substrate for rOCT1. Tetraethylammonium (TEA) and dTub competitively inhibit the other's uptake by rOCT1 in a manner consistent with their interaction at a common site. Although 67% homologous with rOCT1, rOCT2 does not mediate the uptake of these nucleosides. Kinetic studies demonstrated the difference in substrate specificity between rOCT1 and rOCT2 to be largely due to a poor affinity of rOCT2 for dTub+. This difference in affinity is located within transmembrane domains 2–7 as determined by chimeric constructs. ^ OCT1 knockout mice were used to evaluate the role of OCT1 in the renal secretion of dTub. No significant difference in tissue distribution and urinary excretion of dTub was observed between the knockout and wild-type mice, indicating that OCT1 is not necessary for the renal secretion of dTub. Apical transporters are postulated to participate in its active secretion. To characterize a possible apical transporter, we screened several renal cell lines for a nucleoside-sensitive OCT. American opossum kidney proximal tubule cells (OK) express a TEA efflux transporter that is inhibited by dTub and other nucleoside analogs. This carrier is metabolic-dependent and distinct from the cloned OCTs to date, i.e. it is sodium- and proton-independent. In conclusion, dTub is a good substrate for OCT1; however, this OCT is not necessary for its renal secretion in mice. The novel TEA efflux transporter identified in OK cells is likely to participate in the renal secretion of dTub and perhaps other nucleoside analogs. ^

Simultaneous induction of NKG2D and NKG2D ligand for promoting immune surveillance by IL-12 plus doxorubicin treatment

NKG2D (natural killer group 2, member D) and its ligands interaction in tumor microenvironment directs tumor infiltrating immune cells to recognize tumor cells, stimulate cytotoxic effector immune cells, and therefore eradicate tumor cells. IL-12, a cytokine produced by antigen presenting cells, has remarkable antitumor effect by activating innate and adaptive immunity. Doxorubicin, a commonly used chemotherapeutic agent also boosts the host antitumor immune response to cause tumor cell death. Our previous publication suggests that IL-12 plus doxorubicin enhances NKG2D function-dependent inhibition of tumor progression and promotes CD8+T cells infiltrating into tumors. The purpose of this study is to determine the underlying mechanism. Our study reveals a novel function of doxorubicin, which is to augment IL-12–induced NKG2D expression in CD8+T cells but not in NK or CD4+T cells. This observation was further validated by NK and CD8+T cell-depletion studies, in which only depletion of CD8+T cells abolished the expression of NKG2D in lymphocytes. The induced NKG2D expression in CD8+T cells is tightly associated with tumor-specific localization of CD8+T cells and improved antitumor efficacy. The IL-12 plus doxorubicin treatment-induced antitumor efficacy is also due to NKG2D ligand Rae-1 induction in tumors. Rae-1 induction in tumors is a long term effect in multiple tumor models, but not in normal tissues. A novel CD8+T cell direct contact dependent mechanism accounts for Rae-1 induction in vivo and in vitro, and CD80 is the receptor through which CD8+T cells interplay with tumor cells to upregulate Rae-1 on tumor cells. In summary, increased NKG2D expression in CD8+T cells in response to IL-12 plus doxorubicin was closely associated with tumor-specific localization of CD8+T cells and greater antitumor efficacy of the combined regimen than either agent alone. NKG2D ligand Rae-1 induction is triggered by the interaction of CD80 on tumor cells with tumor infiltrating CD+8 T cells.

Proceedings of the Sixteenth Annual Biochemical Engineering Symposium

This volume represents the proceedings of the Sixteenth Annual Biochemical Engineering Symposium held at Kansas State University on April 26, 1986. Some of the papers describe the progress of ongoing projects, and others contain the results of completed projects. Only brief summaries are given of many of the papers that will be published in full elsewhere. ContentsEnd-Product Inhibition of the Acetone-Butanol Fermentation—Bob Kuhn, Colorado State University Effect of Multiple Substrates in Ethanal Fermentations from Cheese Whey—C.J. Wang, University of Missouri Extraction and Fermentation of Ensiled Sweet Sorghum—Karl Noah, Colorado State University Removal of Nucleic Acids from Bakers' Yeast—Richard M. Cordes, Iowa State University Modeling the Effects of Plasmid Replication and Product Repression on the Growth Rate of Recombinant Bacteria—William E. Bentley, University of Colorado Indirect Estimates of Cell Concentrations in Mass Cultivation of Bacterial Cells—Andrew Fisher, University of Missouri A Mathematical Model for Liquid Recirculation in Airlift Columns—C.H.Lee, Kansas State University Characterization of Imperfect Mixing of Batch Reactors by Two Compartment Model—Peter Sohn, University of Missouri First Order Breakage Model for the Degradation of Pullalan in the Batch Fermentor—Stephen A. Milligan, Kansas State University Synthesis and Nuclear Magnetic Resonance of 13C-Labeled Amylopectin and Maltooligosaccharides—Bernard Y. Tao, Iowa State University Preparation of Fungal Starter Culture in Gas Fluidized Bed Reactor—Pal Mihaltz, Colorado State University Yeast Flocculation and Sedimentation—David Szlag, University of Colorado Protein Enrichment of Extrusion Cooked Corn by Solid Substrate Fermentation—Lucas Alvarez-Martinez, Colorado State University Optimum Design of a Hollow Fiber Mammalian Cell Reactor—Thomas Chresand, Colorado State University Gas Chromatography and Nuclear Magnetic Resonance of Trifluoroacetylated Carbohydrates—Steven T. Summerfelt, Iowa State University Kinetic and Bioenergetic Considerations for Modeling Photosynthetic Microbial P~ocesses in Producing Biomass and Treating Wastewater—H. Y. Lee, Kansas State University Mathematical Modeling and Simulation of Bicarbonate-Limited Photsynthetic Growth in Continuous Culture—Craig Curless, Kansas State University Data Acquisition and Control of a Rotary Drum Solid State Fermentor—Mnasria A. Habib, Colorado State University Biodegradation of 2,4-Dichlorophenoxyacetic Acid (2,4-D)—Greg Sinton, Kansas State University

Comparison of Organic and Conventional Crops at the Neely-Kinyon Long-term Agroecological Research Site

The Neely-Kinyon Long-term Agroecological Research (LTAR) site was established in 1998 to study the long-term effects of organic production in Iowa. Treatments at the LTAR site, replicated four times in a completely randomized design, include the following rotations: conventional Corn-Soybean (C-S), organic Corn-Soybean-Oats/Alfalfa (C-SO/A), organic Corn-Soybean-Oats/AlfalfaAlfalfa (C-S-O/A-A) and Corn-SoybeanCorn-Oats/Alfalfa (C-SB-C-O/A). On April 13, 2011, Badger oats were underseeded with BR Goldfinch alfalfa at a rate of 90 lb/acre and 15 lb/acre, respectively. Following harvest of the organic corn plots in 2010, winter rye was no-till drilled at a rate of 75 lb/acre on October 20, 2010.

Comparison of Organic and Conventional Crops at the Neely-Kinyon Long-term Agroecological Research (LTAR) Site

The Neely-Kinyon LTAR site was established in 1998 to study the long-term effects of organic production in Iowa. Treatments at the LTAR site, replicated four times in a completely randomized design, include the following rotations: conventional Corn-Soybean (C-S), organic Corn-Soybean-Oats/Alfalfa (C-S-O/A), organic Corn-Soybean-Oats/Alfalfa-Alfalfa (CS-O/A-A). A new rotation of Corn-SoybeanCorn-Oats/Alfalfa (C-SB-C-O/A) replaced the old S-W/RC rotation.