Calculation of the Relative Chemical Stabilities of Proteins as a Function of Temperature and RedoxChemistry in a Hot Spring

Uncovering the chemical and physical links between natural environments and microbial communities is becoming increasingly amenable owing to geochemical observations and metagenomic sequencing. At the hot spring known as Bison Pool in Yellowstone National Park, the cooling of the water in the outflow channel is associated with an increase in oxidation potential estimated from multiple field-based measurements. Representative groups of proteins whose sequences were derived from metagenomic data also exhibit an increase in average oxidation state of carbon in the protein molecules with distance from the hot-spring source. The energetic requirements of reactions to form selected proteins usedin the model were computed using amino-acid group additivity for the standard molal thermodynamic properties of the proteins, and the relative chemical stabilities of the proteins were investigated by varying temperature, pH and oxidation state, expressed as activity of dissolved hydrogen. The relative stabilities of the proteins were found to track the locations of the sampling sites when the calculations included a function for hydrogen activity that increases with temperature and is higher, or more reducing, than values consistent with measurements of dissolved oxygen, sulfide and oxidation-reduction potential in the field. These findings imply that spatial patterns in the amino acid compositions of proteins can be linked, through energetics of overall chemical reactions representing the formation of the proteins, to the environmental conditions at this hot spring, even if microbial cells maintain considerably different internal conditions. Further applications of the thermodynamic calculations are possible for other natural microbial ecosystems

Shale Investment Dashboard in Ohio Q3 and Q4 2016

This report presents findings from an investigation into shale-related investment in Ohio. The investment estimates are cumulative from July through December of 2016. Prior investments have previously been reported and are available from Cleveland State University. Subsequent reports will estimate additional investment since the date of this report

Particle mass transport in impact electrochemistry

Impact electrochemistry is a set of methods in which individual micro- or nanoscale particles are detected and analyzed at a miniaturized electrode. Quantitative interpretation of the results, in particular the determination of ultralow concentrations, relies heavily on modeling the mass transport of the particles being analyzed. This is particularly subtle since, due to favorable scaling with increasing particle size, migration and convection play a disproportionate role in the transport of such particles compared to that of small molecules. Here we summarize the main governing principles in electrochemically-driven particle transport. We particularly emphasize the difference between particle electrophoresis and small-ion migration, which has led to inaccuracies in the recent literature.</p

Shale Investment Dashboard in Ohio Q1 and Q2 2017

This report presents findings from an investigation into shale-related investment in Ohio. The investment estimates are cumulative from January through June of 2017. Prior investments have previously been reported and are available from Cleveland State University. Subsequent reports will estimate additional investment since the date of this report

Concealed anterograde accessory pathway conduction during the induction of orthodromic reciprocating tachycardia

AbstractThe purpose of this study was to determine whether concealed anterograde accessory pathway conduction occurs during the induction of orthodromic tachycardia by an artrial extrastimulus (S2). Sixteen patients with an overt (n = 9) or concealed (n = 7) accessory pathway had inducible orthodromic tachycardia by S2during an atrial drive (S1) cycle length of 500 to 650 ms. A ventricular extrastimulus (S3) was introduced coincident with the His depolarization resulting from S2during the longest S1S2interval that reproducibly induced orthodromic tachycardia. The S1S3interval was decreased in 10 ms steps until S3reached ventricular refractoriness. Retrograde accessory pathway conduction of S3in the presence and absence of S2was compared at the same S1S3intervals.In the absence of S2there was retrograde accessory pathway conduction after S3in each patient. In the presence of S2, in patients with overt pre-excitation, retrograde accessory pathway conduction after S3was absent in one patient, prolonged in four patients and present only after long S1S3intervals in three patients. Only one patient had unchanged retrograde conduction regardless of the presence or absence of S2. In patients with a concealed accessory pathway, retrograde accessory pathway conduction after S3was absent in five patients and was prolonged in two. Thus, concealed anterograde accessory pathway conduction was present in 15 of 16 patients at the time of orthodromic tachycardia induction.In conclusion, concealed anterograde accessory pathway conduction occurs in a majority of patients with an overt or a concealed accessory pathway during induction of orthodromic tachycardia by an atrial extrastimulus. In some patients, the initiation of orthodromic tachycardia may depend on a critical interaction between the degree of concealed anterograde accessory pathway conduction and atrioventricular conduction delay after S2

CIDP Diagnostic Criteria and Response to Treatment

AbstractIntroduction: Diagnostic criteria for CIDP have been proven useful for clinical trials. However, use of these criteria in clinics has been limited by time constraints and unknown usefulness in predicting outcomes. Methods: A retrospective chart review of CIDP patients at the University of Kansas seen between 2008 and 2014 was performed. We determined the diagnostic criteria fulfilled by each patient and assessed treatment responses. A positive response was defined by improvement sensory or motor examination as determined by a neuromuscular physician.Results: There were 38 total patients included in the study. The response rate to IVIG in patients who fulfilled EFNS/PNS criteria was 20/22 (90.1%). Among patients who fulfilled AAN criteria, 8/9 (88.9%) responded positively to IVIG. Slightly lower response rates were seen in patients fulfilling INCAT criteria and Saperstein criteria at 10/15 (66.7%) and 12/17 (70.6%), respectively.Discussion: EFNS/PNS and AAN criteria can similarly predict IVIG treatment response

Changes in Carbon Oxidation State of Metagenomes Along Geochemical Redox Gradients

There is widespread interest in how geochemistry affects the genomic makeup of microbial communities, but the possible impacts of oxidation-reduction (redox) conditions on the chemical composition of biomacromolecules remain largely unexplored. Here we document systematic changes in the carbon oxidation state, a metric derived from the chemical formulas of biomacromolecular sequences, using published metagenomic and metatranscriptomic datasets from 18 studies representing different marine and terrestrial environments. We find that the carbon oxidation states of DNA, as well as proteins inferred from coding sequences, follow geochemical redox gradients associated with mixing and cooling of hot spring fluids in Yellowstone National Park (USA) and submarine hydrothermal fluids. Thermodynamic calculations provide independent predictions for the environmental shaping of the gene and protein composition of microbial communities in these systems. On the other hand, the carbon oxidation state of DNA is negatively correlated with oxygen concentration in marine oxygen minimum zones. In this case, a thermodynamic model is not viable, but the low carbon oxidation state of DNA near the ocean surface reflects a low GC content, which can be attributed to genome reduction in organisms adapted to low-nutrient conditions. We also present evidence for a depth-dependent increase of oxidation state at the species level, which might be associated with alteration of DNA through horizontal gene transfer and/or selective degradation of relatively reduced (AT-rich) extracellular DNA by heterotrophic bacteria. Sediments exhibit even more complex behavior, where carbon oxidation state minimizes near the sulfate-methane transition zone and rises again at depth; markedly higher oxidation states are also associated with older freshwater-dominated sediments in the Baltic Sea that are enriched in iron oxides and have low organic carbon. This geobiochemical study of carbon oxidation state reveals a new aspect of environmental information in metagenomic sequences, and provides a reference frame for future studies that may use ancient DNA sequences as a paleoredox indicator