Characterization of beneficial mutations in unsaturated fatty acid biosynthesis that are recurrent dead-ends in a long-term evolution experiment with Escherichia coli

textMicrobes provide an invaluable tool for watching evolution in action. Throughout more than 55,000 generations, lineages of Escherichia coli cells in a long-term evolution experiment (LTEE) grew in a minimal glucose environment and explored different mutational paths to higher fitness. Genome sequencing identifies genes that accrue mutations early in evolution across the twelve evolving populations. These parallel mutations typically provide a significant fitness benefit and often fix in the population. However, some mutations seem to lead to evolutionary dead-ends. In 7 of the 12 LTEE populations, lineages with mutations in the gene coding for the lipid synthesis repressor, fabR, gain traction within the population, but always eventually go extinct. To parse out the fitness benefits and downstream effects, strains with these mutations were constructed. These mutations increase the growth rate and may affect the length of lag phase after each daily transfer. Another mutation that often fixes within eventually successful clades is within the stress response global regulator spoT. A connection between spoT and fabR mutations could be the key to understanding the eventual outcomes within these lineages. Decreased fatty acid synthesis (repressed by FabR) during glucose starvation activates the global repressor SpoT to produce the cellular "alarmone" (p)ppGpp, inhibiting cell growth during the stringent response. Thus, it is possible that fabR mutations that prolong fatty acid synthesis and spoT mutations that alter the production of (p)ppGpp may both benefit cells by affecting the stringent response. In addition, when these two mutations are combined in a single strain they confer nearly an identical increase in fitness as the single mutations alone, strengthening the argument that they may target the same cellular pathway. Preliminary gene expression analyses of fabR mutants confirmed an expected increase in unsaturated fatty acid synthesis and also found signs that membrane damage responses were activated. It is possible that fabR mutants are near a stability cliff that makes them unable to access otherwise beneficial further mutations. Ultimately, this work will elucidate how interactions between the physiological effects of mutations on evolutionary paths to higher fitness may lead to differences in evolvability that ultimately determine success or extinction.Microbiolog

Technological Change in the Wine Market? The Role of QR Codes and Wine Apps in Consumer Wine Purchases

As an experiential good, wine purchases in the absence of tastings are often challenging and information-laden decisions. Technology has shaped the way consumers negotiate this complex purchase process. Using a sample of 631 US wine consumers, this research aims to identify the role of mobile applications and QR codes in the wine purchase decision. Results suggest that wine consumers that consider themselves wine connoisseurs or experts, enjoy talking about wine, and are interested in wine that is produced locally, organically, or sustainably are more likely to employ technology in their wine purchase decision. While disruption appears to have occurred on the supply side (number of wine applications available and the number of wine labels with a QR code), this research suggests that relatively little change is occurring on the demand side (a relatively small segment of the population—those already interested in wine—are employing the technology to aid in their purchase decision)

The Effects of Regulations on Private School Choice Program Participation: Experimental Evidence from Florida

When deciding whether to participate in a private school choice program, private school leaders weigh additional financial benefits against additional regulatory costs. In theory, raising the costs associated with entering private school choice programs should reduce the likelihood that individual schools participate in those programs. However, very little empirical evidence exists evaluating this idea. While a few studies suggest that more highly regulated programs are correlated with lower levels of school participation, none have established causal relationships between these factors, and none have determined which program regulations are the most costly. Because it is nearly impossible to randomly assign program regulations to individual private schools, we use surveys to randomly assign different regulations to 3,080 private school leaders in Florida and ask them whether they would participate in a new private school choice program during the following school year. Relative to no regulations, our most conservative models find that open-enrollment mandates reduce the likelihood that private schools are certain to participate by about 17 percentage points, or 70 percent. State standardized testing requirements reduce the likelihood that private schools are certain to participate by 11 percentage points, or 44 percent. We find no evidence to suggest that the prohibition of copayment affects program participation overall. These estimates of the impact of regulatory requirements on the expressed willingness of private school principals to participate in a private school choice program are causal because random assignment leads to equivalence in expectation across treatment and control groups on both measurable and unmeasurable factors. We also find evidence to suggest that higher quality schools – as measured by tuition levels and enrollment trends – are more likely to be deterred by program regulation

The Effects of Regulations on Private School Choice Program Participation: Experimental Evidence from California and New York

Although private school voucher programs provide subsidies to students for tuition and other education-related costs, private school leaders weigh program participation against any associated regulatory costs. The higher the regulatory costs of participation, the less likely a private school is to participate in a school voucher program. Since we do not know with certainty which regulations will be viewed by school leaders as more or less costly, we explore whether specific regulations that are common to private school choice programs do or do not deter likely voucher program participation.We use surveys to randomly assign different regulations to 4,825 private school leaders in the states of California and New York and ask them whether or not they would participate in a new private school choice program during the following school year. Relative to no regulations, our most conservative models find that open-enrollment mandates reduce the likelihood that private school leaders are certain to participate in a hypothetical choice program by about 19 percentage points, or 60 percent. State standardized testing requirements reduce the likelihood that private school leaders are certain to participate by 9 percentage points, or 29 percent. We find no evidence to suggest that the prohibition of copayment or nationally norm-referenced testing requirements affect the overall willingness to participate in a school choice program

An overview of mechanisms of desiccation tolerance in selected angiosperm resurrection plants

The vegetative tissues of resurrection plants, like seeds, can tolerate desiccation to 5% relative water content (RWC) for extended periods and yet resume full metabolic activity on re-watering. In this review we will illustrate how this is achieved in a variety of angiosperm resurrection plants, our studies ranging from the ecophysiological to the biochemical level. At the whole plant level, leaf folding and other anatomical changes serve to minimise light and mechanical stress associated with drying and rehydration. The mechanisms of cell wall folding are described for Craterostigma wilmsii and Myrothanmus flabellifolia. Free radicals, radical oxygen species (ROS) usually generated under water-deficit stress by photosynthesis, are minimised by either homoiochlorophylly (e.g. C. wilmsii and M. flabellifolia) or poikilochlorophylly (e.g. Xerophyta sp.). The antioxidant systems of these plants effectively deal with ROS generated by other metabolic processes. In addition to antioxidants common to most plants, resurrection plants also accumulate polyphenols such as 3, 4, 5 tri-O-galloylquinic acid in M. flabellifolia, and seed-associated antioxidants (e.g. 1-cys-peroxiredoxin and metallothionines) as effective ROS scavengers. Sucrose accumulates at low RWC, presumably protecting the sub-cellular milieu against desiccation-induced macromolecular denaturation

The fate of murine double minute X (MdmX) is dictated by distinct signaling pathways through murine double minute 2 (Mdm2)

Mouse double minute 2 (Mdm2) and MdmX dimerize in response to low levels of genotoxic stress to function in a ubiquitinating complex, which signals for destabilization of p53. Under growth conditions, Mdm2 functions as a neddylating ligase, but the importance and extent of MdmX involvement in this process are largely unknown. Here we show that when Mdm2 functions as a neddylating enzyme, MdmX is stabilized. Furthermore, we demonstrate that under growth conditions, MdmX enhances the neddylation activity of Mdm2 on p53 and is a substrate for neddylation itself. Importantly, MdmX knockdown in MCF-7 breast cancer cells resulted in diminished neddylated p53, suggesting that MdmX is important for Mdm2-mediated neddylation. Supporting this finding, the lack of MdmX in transient assays or in p53/MdmX-/- MEFs results in decreased or altered neddylation of p53 respectively; therefore, MdmX is a critical component of the Mdm2-mediated neddylating complex. c-Src is the upstream activator of this Mdm2-MdmX neddylating pathway and loss of Src signaling leads to the destabilization of MdmX that is dependent on the RING (Really Interesting New Gene) domain of MdmX. Treatment with a small molecule inhibitor of neddylation, MLN4924, results in the activation of Ataxia Telangiectasia Mutated (ATM). ATM phosphorylates Mdm2, converting Mdm2 to a ubiquitinating enzyme which leads to the destabilization of MdmX. These data show how distinct signaling pathways engage neddylating or ubiquitinating activities and impact the Mdm2-MdmX axis

Reporting quality of music intervention research in healthcare: A systematic review

INTRODUCTION: Concomitant with the growth of music intervention research, are concerns about inadequate intervention reporting and inconsistent terminology, which limits validity, replicability, and clinical application of findings. OBJECTIVE: Examine reporting quality of music intervention research, in chronic and acute medical settings, using the Checklist for Reporting Music-based Interventions. In addition, describe patient populations and primary outcomes, intervention content and corresponding interventionist qualifications, and terminology. METHODS: Searching MEDLINE, PubMed, CINAHL, HealthSTAR, and PsycINFO we identified articles meeting inclusion/exclusion criteria for a five-year period (2010-2015) and extracted relevant data. Coded material included reporting quality across seven areas (theory, content, delivery schedule, interventionist qualifications, treatment fidelity, setting, unit of delivery), author/journal information, patient population/outcomes, and terminology. RESULTS: Of 860 articles, 187 met review criteria (128 experimental; 59 quasi-experimental), with 121 publishing journals, and authors from 31 countries. Overall reporting quality was poor with <50% providing information for four of the seven checklist components (theory, interventionist qualifications, treatment fidelity, setting). Intervention content reporting was also poor with <50% providing information about the music used, decibel levels/volume controls, or materials. Credentialed music therapists and registered nurses delivered most interventions, with clear differences in content and delivery. Terminology was varied and inconsistent. CONCLUSIONS: Problems with reporting quality impedes meaningful interpretation and cross-study comparisons. Inconsistent and misapplied terminology also create barriers to interprofessional communication and translation of findings to patient care. Improved reporting quality and creation of shared language will advance scientific rigor and clinical relevance of music intervention research

Mutant and wild-type p53 form complexes with p73 upon phosphorylation by the kinase JNK

The transcription factors p53 and p73 are critical to the induction of apoptotic cell death, particularly in response to cell stress that activates c-Jun N-terminal kinase (JNK). Mutations in the DNA-binding domain of p53, which are commonly seen in cancers, result in conformational changes that enable p53 to interact with and inhibit p73, thereby suppressing apoptosis. In contrast, wild-type p53 reportedly does not interact with p73. We found that JNK-mediated phosphorylation of Thr81 in the proline-rich domain (PRD) of p53 enabled wild-type p53, as well as mutant p53, to form a complex with p73. Structural algorithms predicted that phosphorylation of Thr81 exposes the DNA-binding domain in p53 to enable its binding to p73. The dimerization of wild-type p53 with p73 facilitated the expression of apoptotic target genes [such as those encoding p53–up-regulated modulator of apoptosis (PUMA) and Bcl-2-associated X protein (BAX)] and, subsequently, the induction of apoptosis in response to JNK activation by cell stress in various cells. Thus, JNK phosphorylation of mutant and wild-type p53 promotes the formation of a p53/p73 complex that determines cell fate: apoptosis in the context of wild-type p53 or cell survival in the context of the mutant. These findings refine our current understanding of both the mechanistic links between p53 and p73 and the functional role for Thr81 phosphorylation

Mdm2 mediated neddylation of pVHL blocks the induction of anti-angiogenic factors.

Mutations in the tumor suppressor TP53 are rare in renal cell carcinomas. p53 is a key factor for inducing anti-angiogenic genes and RCC are highly vascularized, which suggests that p53 is inactive in these tumors. One regulator of p53 is the Mdm2 oncogene, which is correlated with high-grade, metastatic tumors. However, the sole activity of Mdm2 is not just to regulate p53, but it can also function independent of p53 to regulate the early stages of metastasis. Here, we report that the oncoprotein Mdm2 can bind directly to the tumor suppressor VHL, and conjugate nedd8 to VHL within a region that is important for the p53-VHL interaction. Nedd8 conjugated VHL is unable to bind to p53 thereby preventing the induction of anti-angiogenic factors. These results highlight a previously unknown oncogenic function of Mdm2 during the progression of cancer to promote angiogenesis through the regulation of VHL. Thus, the Mdm2-VHL interaction represents a pathway that impacts tumor angiogenesis