Identification and nucleotide sequences of mxaA, mxaC, mxaK, mxaL, and mxaD genes from Methylobacterium extorquens AM1

The DNA sequence for a 4.4-kb HindIII-XhoI Methylobacterium extorquens AM1 DNA fragment that is known to contain three genes (mxaAKL) involved in incorporation of calcium into methanol dehydrogenase (I. W. Richardson and C. Anthony, Biochem. J. 287:709-7115, 1992) was determined. Five complete open reading frames and two partial open reading frames were found, suggesting that this region contains previously unidentified genes. A combination of sequence analysis, mutant complementation data, and gene expression studies showed that these genes correspond to mxaSACKLDorf1. Of the three previously unidentified genes (mxaC, mxaD, and orf1), mutant complementation studies showed that mxaC is required for methanol oxidation, while the function of the other two genes is still unknown

Statistical Models of Runway Incursions Based on Runway Intersections and Taxiways

According to the Federal Aviation Administration (FAA), the number of runway incursions are rising. The configuration of runways and taxiways at airports has been identified by the FAA as possibly being related to the number of incursions. In this paper, the relationship between airport geometry factors and the number of runway incursions at specific United States airports is explored using statistical analyses. Airport operations data from the FAA Air Traffic Activity System, runway incursion data from the FAA Aviation Safety Information Analysis and Sharing System from 2009 through 2013, and airport geometry data created using airport geometry features from the FAA airport diagrams were collected. The 30 busiest airports with intersecting runways and the 30 busiest airports without intersecting runways were compared. As expected, the analysis of the data show that at alpha = 0.05 level, runway incursions occur at a more frequent rate for airports with intersecting runways compared to airports with no intersecting runways. In the second phase of statistical analysis, the number of incursions per 100,000 operations at the 63 busiest United States airports was analyzed using four airport geometry factors as independent variables in regression analysis. The resulting regression equation was significant at the alpha = 0.05 level and contained two independent variables: the number of crossing taxiways per runway and the number of runway intersections per runway. The equation and each variable in the equation are statistically significant and the equation explains 17.3% of the variation in incursions per 100,000 operations

Protein Engineering of a Spectroscopic Probe into Malate Dehydrogenase (MDH)

Malate dehydrogenase (MDH) is an enzyme that has a key role in biological processes, like the Krebs cycle. Specifically, it reversibly catalyzes the interconversion of (S)-malate with NAD+ to oxaloacetate and NADH. Once oxaloacetate is synthesized, MDH dispatches it to citrate synthase, but it is not clear how this happens. One theory is that MDH channels it to citrate synthase by forming a metabolon, a mechanism for direct channeling, preventing diffusion of reaction intermediates into a bulk matrix. There is a lack of research in this area due to the absence of a spectroscopic probe necessary to visualize MDH’s conformational changes. Therefore, a method was tested to incorporate a fluorescent landmark into MDH’s structure and thus be used in future research to reveal the interactions between MDH and citrate synthase. Specific amino acids of MDH were mutated to tryptophan, an amino acid known to fluoresce (V189, I319, A120, I136, P119, G218). The coding sequence for the wildtype MDH and mutant MDHs were incorporated into plasmids and bacterially transformed into Escherichia coli. Both wildtype and mutant proteins were over-expressed, then purified by nickel affinity chromatography using a hexahistidine tag on the N-terminus of MDH. Data will demonstrate that I139W, V189W, and A120W had significantly lower activity than wildtype MDH, and the same is predicted for I136W. I139W and V189W emitted fluorescence at 290 nm, but I136W did not. The mutations P119W and G218W could not be overexpressed or purified. Next steps in design of a fluorescent, active MDH will be discussed

Augmented cardiac growth hormone signaling contributes to cardiomyopathy following genetic disruption of the cardiomyocyte circadian clock

Circadian clocks regulate numerous biological processes, at whole body, organ, and cellular levels. This includes both hormone secretion and target tissue sensitivity. Although growth hormone (GH) secretion is time-of-day-dependent (increased pulse amplitude during the sleep period), little is known regarding whether circadian clocks modulate GH sensitivity in target tissues. GH acts in part through induction of insulin-like growth factor 1 (IGF1), and excess GH/IGF1 signaling has been linked to pathologies such as insulin resistance, acromegaly, and cardiomyopathy. Interestingly, genetic disruption of the cardiomyocyte circadian clock leads to cardiac adverse remodeling, contractile dysfunction, and reduced lifespan. These observations led to the hypothesis that the cardiomyopathy observed following cardiomyocyte circadian clock disruption may be secondary to chronic activation of cardiac GH/IGF1 signaling. Here, we report that cardiomyocyte-specific BMAL1 knockout (CBK) mice exhibit increased cardiac GH sensitivity, as evidenced by augmented GH-induced STAT5 phosphorylation (relative to littermate controls) in the heart (but not in the liver). Moreover

Brief motivational interventions for college student drinking may not be as powerful as we think: An individual participant-level data meta-analysis

Background For over two decades, brief motivational interventions (BMIs) have been implemented on college campuses to reduce heavy drinking and related negative consequences. Such interventions include in-person motivational interviews (MIs), often incorporating personalized feedback (PF), and stand-alone PF interventions delivered via mail, computer, or the Web. Both narrative and meta-analytic reviews using aggregate data from published studies suggest at least short-term efficacy of BMIs, although overall effect sizes have been small. Method The present study was an individual participant-level data (IPD) meta-analysis of 17 randomized clinical trials evaluating BMIs. Unlike typical meta-analysis based on summary data, IPD meta-analysis allows for an analysis that correctly accommodates the sampling, sample characteristics, and distributions of the pooled data. In particular, highly skewed distributions with many zeroes are typical for drinking outcomes, but have not been adequately accounted for in existing studies. Data are from Project INTEGRATE, one of the largest IPD meta-analysis projects to date in alcohol intervention research, representing 6,713 individuals each with two to five repeated measures up to 12 months post-baseline. Results We used Bayesian multilevel over-dispersed Poisson hurdle models to estimate intervention effects on drinks per week and peak drinking, and Gaussian models for alcohol problems. Estimates of overall intervention effects were very small and not statistically significant for any of the outcomes. We further conducted post hoc comparisons of three intervention types (Individual MI with PF, PF only, and Group MI) vs. control. There was a small, statistically significant reduction in alcohol problems among participants who received an individual MI with PF. Short-term and long-term results were similar. Conclusions The present study questions the efficacy and magnitude of effects of BMIs for college drinking prevention and intervention and suggests a need for the development of more effective intervention strategies

Project INTEGRATE: An Integrative Study of Brief Alcohol Interventions for College Students

This paper provides an overview of a study that synthesizes multiple, independently collected alcohol intervention studies for college students into a single, multisite longitudinal data set. This research embraced innovative analytic strategies (i.e., integrative data analysis or meta-analysis using individual participant-level data), with the overall goal of answering research questions that are difficult to address in individual studies such as moderation analysis, while providing a built-in replication for the reported efficacy of brief motivational interventions for college students. Data were pooled across 24 intervention studies, of which 21 included a comparison or control condition and all included one or more treatment conditions. This yielded a sample of 12,630 participants (42% men; 58% first-year or incoming students). The majority of the sample identified as White (74%), with 12% Asian, 7% Hispanic, 2% Black, and 5% other/mixed ethnic groups. Participants were assessed two or more times from baseline up to 12 months, with varying assessment schedules across studies. This paper describes how we combined individual participant-level data from multiple studies, and discusses the steps taken to develop commensurate measures across studies via harmonization and newly developed Markov chain Monte Carlo algorithms for two-parameter logistic item response theory models and a generalized partial credit model. This innovative approach has intriguing promises, but significant barriers exist. To lower the barriers, there is a need to increase overlap in measures and timing of follow-up assessments across studies, better define treatment and control groups, and improve transparency and documentation in future single, intervention studies