Structure function studies of the NDHD4 protein of the co₂ uptake mechanism in Synechococcus elongatus sp. pcc 7942

To overcome the poor kinetic efficiency of Rubisco, cyanobacteria have evolved a CO2-concentrating mechanism (CCM) that maintains high carbonation levels in the cytoplasm. The cyanobacterial CCM utilizes a modified NADH dehydrogenase oxidoreductases (NDH-1⌄3,4) to hydrate CO2 to bicarbonate (HCO⌄3-) using photosynthetic redox energy. The energetic coupling effectively captures the inorganic carbon (C⌄i) in the cell in a form that is efficiently used within the carboxysome for fixation into sugars. The coupling mechanism by NDH-1⌄3,4, along with the rest of the CCM, acts as a supercharger for CO2, saturating Rubisco’s active sites and avoiding photorespiration.Here, I test the hypothesis that proton-pumping by the antiporter-like NdhD4 subunit of the NDH-1⌄4 complex is essential for coupling of CO2 hydration to NDH-1 electron transfer. Structural modeling shows that amino acids involved in proton pumping in other species (e.g., E. coli) are conserved in NdhD4. The overall carbonic anhydrase (CA)-like reaction in the Zn-containing CupB subunit is somehow coupled to an unknown energy source to drive the reaction far-from-equilibrium in favor of bicarbonate production. By analogy with known carbonic anhydrases (CAs) and characteristics of CupB mutants, we hypothesize that the NdhD4 protein functions to trap and remove protons produced in the CO⌄2- hydration reaction by pumping them across to the luminal side of the membrane away from the anhydrase active site and avoiding the back-reaction and driving the reaction in favor of HCO⌄3- production. To probe the NdhD4 subunit’s role in CO2 hydration, I identified and mutated several residues that likely effect the proton trapping and translocating ability of the subunit. When mutated, these residues alter the photosynthetic ability of the cell, indicating that they are critical for optimal proton translocation and therefore CO2 hydrating

Medical training simulation for central venous catheterization

Our Creative Inquiry, in collaboration with clinicians, local hospitals, and MBA students, has involved the development, testing, and commercialization of a central venous catheterization training simulator. Medical training simulators are important tools for educating physicians without needing to practice on patients. Central venous catheterization (CVC) is the insertion of a catheter into a sizable vein in order to deliver a large influx of drugs to the heart. The risky nature of the procedure comes from the proximity of the vein to the heart, lungs, and major arteries. Many complications can arise, often the cause of expensive and ineffective training methods. We have created an affordable simulator with features that address the limitations of current simulators, including a fully rotatable head, proper anatomical landmarks, and ultrasoundability. Our patent-pending design is currently being prepared for manufacturing and marketing in hopes of increasing the safety of CVC procedures

Lunar Dust Simulant in Mechanical Component Testing - Paradigm and Practicality

Due to the uniquely harsh lunar surface environment, terrestrial test activities may not adequately represent abrasive wear by lunar dust likely to be experienced in mechanical systems used in lunar exploration. Testing to identify potential moving mechanism problems has recently begun within the NASA Engineering and Safety Center Mechanical Systems Lunar Dust Assessment activity in coordination with the Exploration Technology and Development Program Dust Management Project, and these complimentary efforts will be described. Specific concerns about differences between simulant and lunar dust, and procedures for mechanical component testing with lunar simulant will be considered. In preparing for long term operations within a dusty lunar environment, the three fundamental approaches to keeping mechanical equipment functioning are dust avoidance, dust removal, and dust tolerance, with some combination of the three likely to be found in most engineering designs. Methods to exclude dust from contact with mechanical components would constitute mitigation by dust avoidance, so testing seals for dust exclusion efficacy as a function of particle size provides useful information for mechanism design. Dust of particle size less than a micron is not well documented for impact on lunar mechanical components. Therefore, creating a standardized lunar dust simulant in the particulate size range of ca. 0.1 to 1.0 micrometer is useful for testing effects on mechanical components such as bearings, gears, seals, bushings, and other moving mechanical assemblies. Approaching actual wear testing of mechanical components, it is beneficial to first establish relative wear rates caused by dust on commonly used mechanical component materials. The wear mode due to dust within mechanical components, such as abrasion caused by dust in grease(s), needs to be considered, as well as the effects of vacuum, lunar thermal cycle, and electrostatics on wear rate

Disambiguating Descriptions: Mapping Digital Special Collections Metadata into Linked Open Data Formats

In this poster we describe the Linked Open Data (LOD) for Digital Special Collections project at the University of Illinois at Urbana-Champaign and describe some of the particular challenges that legacy metadata poses for representation in LOD formats. LOD formats are primarily based on the World Wide Web Consortium’s Resource Description Framework standard which demands both that entities be named by opaque universal identifiers whenever possible but also that metadata descriptions for entities be as unambiguous as possible. The challenges for disambiguating those descriptions are illustrated through examples drawn from digital special collections based at four different digital librariesOpe

Metastatic progression and gene expression between breast cancer cell lines from African American and Caucasian women

African American (AA) women have a lower overall incidence of breast cancer than do Caucasian (CAU) women, but a higher overall mortality. Little is known as to why the incidence of breast cancer is lower yet mortality is higher in AA women. Many studies speculate that this is only a socio-economical problem. This investigation suggests the possibility that molecular mechanisms contribute to the increased mortality of AA women with breast cancer. This study investigates the expression of 14 genes which have been shown to play a role in cancer metastasis. Cell lines derived from AA and CAU patients were analyzed to demonstrate alterations in the transcription of genes known to be involved in cancer and the metastatic process. Total RNA was isolated from cell lines and analyzed by RT-PCR analysis. Differential expression of the 14 targeted genes between a spectrum model (6 breast cancer cell lines and 2 non-cancer breast cell lines) and a metastasis model (12 metastatic breast cancer cell lines) were demonstrated. Additionally, an in vitro comparison of the expression established differences in 5 of the 14 biomarker genes between African American and Caucasian breast cell lines. Results from this study indicates that altered expression of the genes Atp1b1, CARD 10, KLF4, Spint2, and Acly may play a role in the aggressive phenotype seen in breast cancer in African American women

Delays and Interruptions in the Acute Medical Unit clerking process – an observational study

Objectives: It is recommended that patients are seen within 4 h of arrival in Acute Medical Units in English hospitals. This study explored the frequency and nature of interruptions and delays potentially affecting the duration of the Acute Medical Unit admission process and the quality of care provided. Design: The admission process was directly observed for patients admitted to the Acute Medical Unit over four one week periods, November 2009 to April 2011. Setting: UK teaching hospital Acute Medical Unit. Participants: Hospital staff n¼36. Main outcome measures: Patient waiting times, duration of clerking, number of interruptions and/or delays. Results: Thirty-five doctors and one nurse practitioner were observed admitting 71 medical patients, 48/71 (68%) patients were clerked within 4 h of arrival. A delay and/or interruption affected 49/71 (69%) patients. Sixty-six interruptions were observed in 36/71 (51%) of admissions, of these 19/36 (53%) were interrupted more than once. The grade of doctor had no bearing on the frequency of interruption; however, clerking took significantly longer when interrupted; overall doctors grade ST1 and above were quicker at clerking than foundation doctors. Delays affected 31/71 (44%) of admissions, 14/31 (45%) involved X-rays or ECGs; other causes of delays included problems with equipment and computers. Conclusion: Interruptions and delays regularly occurred during the admission process in the study hospital which impacts adversely on patient experience and compliance with the recommended 4-h timeframe, further work is required to assess the impact on patient safety. Data obtained from this observational study were used to guide operational changes to improve the process

Src Binds Cortactin Through An Sh2 Domain Cystine-Mediated Linkage

Tyrosine-kinase-based signal transduction mediated by modular protein domains is critical for cellular function. The Src homology (SH)2 domain is an important conductor of intracellular signaling that binds to phosphorylated tyrosines on acceptor proteins, producing molecular complexes responsible for signal relay. Cortactin is a cytoskeletal protein and tyrosine kinase substrate that regulates actin-based motility through interactions with SH2-domain-containing proteins. The Src kinase SH2 domain mediates cortactin binding and tyrosine phosphorylation, but how Src interacts with cortactin is unknown. Here we demonstrate that Src binds cortactin through cystine bonding between Src C185 in the SH2 domain within the phosphotyrosine binding pocket and cortactin C112/246 in the cortactin repeats domain, independent of tyrosine phosphorylation. Interaction studies show that the presence of reducing agents ablates Src-cortactin binding, eliminates cortactin phosphorylation by Src, and prevents Src SH2 domain binding to cortactin. Tandem MS/MS sequencing demonstrates cystine bond formation between Src C185 and cortactin C112/246. Mutational studies indicate that an intact cystine binding interface is required for Src-mediated cortactin phosphorylation, cell migration, and pre-invadopodia formation. Our results identify a novel phosphotyrosine-independent binding mode between the Src SH2 domain and cortactin. Besides Src, one quarter of all SH2 domains contain cysteines at or near the analogous Src C185 position. This provides a potential alternative mechanism to tyrosine phosphorylation for cysteine-containing SH2 domains to bind cognate ligands that may be widespread in propagating signals regulating diverse cellular functions

Antigen Sensitization Influences Organophosphorus Pesticide–Induced Airway Hyperreactivity

BackgroundRecent epidemiologic studies have identified organophosphorus pesticides (OPs) as environmental factors potentially contributing to the increase in asthma prevalence over the last 25 years. In support of this hypothesis, we have demonstrated that environmentally relevant concentrations of OPs induce airway hyperreactivity in guinea pigs.ObjectivesSensitization to allergen is a significant contributing factor in asthma, and we have shown that sensitization changes virus-induced airway hyperreactivity from an eosinophil-independent mechanism to one mediated by eosinophils. Here, we determine whether sensitization similarly influences OP-induced airway hyperreactivity.MethodsNonsensitized and ovalbumin-sensitized guinea pigs were injected subcutaneously with the OP parathion (0.001-1.0 mg/kg). Twenty-four hours later, animals were anesthetized and ventilated, and bronchoconstriction was measured in response to either vagal stimulation or intravenous acetylcholine. Inflammatory cells and acetylcholinesterase activity were assessed in tissues collected immediately after physiologic measurements.ResultsOvalbumin sensitization decreased the threshold dose for parathion-induced airway hyperreactivity and exacerbated parathion effects on vagally induced bronchoconstriction. Pretreatment with antibody to interleukin (IL)-5 prevented parathion-induced hyperreactivity in sensitized but not in nonsensitized guinea pigs. Parathion did not increase the number of eosinophils in airways or the number of eosinophils associated with airway nerves nor did it alter eosinophil activation as assessed by major basic protein deposition.ConclusionsAntigen sensitization increases vulnerability to parathion-induced airway hyperreactivity and changes the mechanism to one that is dependent on IL-5. Because sensitization to allergens is characteristic of 50% of the general population and 80% of asthmatics (including children), these findings have significant implications for OP risk assessment, intervention, and treatment strategies

Converting simulated total dry matter to fresh marketable yield for field vegetables at a range of nitrogen supply levels

Simultaneous analysis of economic and environmental performance of horticultural crop production requires qualified assumptions on the effect of management options, and particularly of nitrogen (N) fertilisation, on the net returns of the farm. Dynamic soil-plant-environment simulation models for agro-ecosystems are frequently applied to predict crop yield, generally as dry matter per area, and the environmental impact of production. Economic analysis requires conversion of yields to fresh marketable weight, which is not easy to calculate for vegetables, since different species have different properties and special market requirements. Furthermore, the marketable part of many vegetables is dependent on N availability during growth, which may lead to complete crop failure under sub-optimal N supply in tightly calculated N fertiliser regimes or low-input systems. In this paper we present two methods for converting simulated total dry matter to marketable fresh matter yield for various vegetables and European growth conditions, taking into consideration the effect of N supply: (i) a regression based function for vegetables sold as bulk or bunching ware and (ii) a population approach for piecewise sold row crops. For both methods, to be used in the context of a dynamic simulation model, parameter values were compiled from a literature survey. Implemented in such a model, both algorithms were tested against experimental field data, yielding an Index of Agreement of 0.80 for the regression strategy and 0.90 for the population strategy. Furthermore, the population strategy was capable of reflecting rather well the effect of crop spacing on yield and the effect of N supply on product grading