Determination of Real-Time Efflux Phenotypes in Escherichia coli AcrB Binding Pocket Phenylalanine Mutants Using a 1,2′-Dinaphthylamine Efflux Assay

To evaluate the importance of phenylalanine residues for substrate transport in the Escherichia coli efflux pump protein AcrB, we subjected Phe-to-Ala binding pocket mutants to a real-time efflux assay with the novel near-infrared lipophilic membrane probe 1,2′-dinaphthylamine (1,2′-DNA). All mutations, with the exception of F617A, led to considerable retardation of efflux. F610A was the point mutation with the most pronounced impact, followed by F628A, F615A, F136A, and F178A. This is the first study to demonstrate the importance of single phenylalanine residues within the AcrB binding pocket for real-time substrate transport

Light-induced expression of ipt from Agrobacterium tumefaciens results in cytokinin accumulation and osmotic stress symptoms in transgenic tobacco

Cytokinins are plant growth regulators that induce shoot formation, inhibit senescence and root growth. Experiments with hydroponically grown tobacco plants, however, indicated that exogenously applied cytokinin led to the accumulation of proline and osmotin. These responses were also associated with environmental stress reactions, such as salt stress, in many plant species. To test whether increased endogenous cytokinin accumulation led to NaCl stress symptoms, the gene ipt from Agrobacterium tumefaciens , encoding isopentenyl transferase, was transformed into Nicotiana tabacum cv. SR-1 under the control of the light-inducible rbcS-3A promoter from pea. In high light (300 μmol PPFD m -2 s -1 ), ipt mRNA was detected and zeatin/zeatin glucoside levels were 10-fold higher than in control plants or when transformants were grown in low light (30 μmol PPFD m -2 s -1 ). High light treatment was accompanied by increased levels of proline and osmotin when compared to low light grown transformed and untransformed control plants. Elevated in planta cytokinin levels induced responses also stimulated by salt stress, suggesting either common or overlapping signaling pathways are initiated independently by cytokinin and NaCl, setting in motion gene expression normally elicited by developmental processes such as flowering or environmental stress.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43438/1/11103_2004_Article_BF00020179.pd

Opioid dose and risk of suicide

Chronic pain is associated with increased risk of suicide, and opioids are commonly used to treat moderate to severe pain. However, the association between opioid dose and suicide mortality has not been examined closely. This retrospective data analysis described the risk of suicide associated with differing prescribed opioid doses. Data were from Veterans Affairs health care system treatment records and the National Death Index. Records analyzed were those of Veterans Affairs patients with chronic pain receiving opioids in fiscal years 2004 to 2005 (N = 123,946). Primary predictors were maximum prescribed morphine-equivalent daily opioid dose and opioid fill type. The main outcome measured was suicide death, by any mechanism, and intentional overdose death during 2004 to 2009. Controlling for demographic and clinical characteristics, higher prescribed opioid doses were associated with elevated suicide risk. Compared with those receiving ≤20 milligrams/day (mg/d), hazard ratios were 1.48 (95% confidence intervals [CI], 1.25-1.75) for 20 to <50 mg/d, 1.69 (95% CI, 1.33-2.14) for 50 to <100 mg/d, and 2.15 (95% CI, 1.64-2.81) for 100+ mg/d. The magnitude of association between opioid dose and suicide by intentional overdose was not substantially different from that observed for the overall measure of suicide mortality. Risk of suicide mortality was greater among individuals receiving higher doses of opioids, and treatment providers may want to view high opioid dose as a marker of elevated risk for suicide. Additional research is needed on opioid use, pain treatment, and suicide

Predictors of injury-related and non-injury-related mortality among veterans with alcohol use disorders

To describe the association between alcohol use disorders (AUDs) and mortality and to examine risk factors for and all-cause, injury-related and non-injury-related mortality among those diagnosed with an AUD.Department of Veterans Affairs, Veterans Health Administration (VHA).A cohort of individuals who received health care in VHA during the fiscal year (FY) 2001 ( n  = 3 944 778), followed from the beginning of FY02 through the end of FY06.Demographics and medical diagnoses were obtained from VHA records. Data on mortality were obtained from the National Death Index.Controlling for age, gender and race and compared to those without AUDs, individuals with AUDs were more likely to die by all causes [hazard ratio (HR) = 2.30], by injury-related (HR = 3.29) and by non-injury-related causes (HR = 2.21). Patients with AUDs died 15 years earlier than individuals without AUDs on average. Among those with AUDs, Caucasian ethnicity and all mental illness diagnoses that were assessed were associated more strongly with injury-related than non-injury-related mortality. Also among those with AUDs, individuals with medical comorbidity and older age were at higher risk for non-injury related compared to injury-related mortality.In users of a large health-care system, a diagnosis of an AUD is associated significantly with increased likelihood of dying by injury and non-injury causes. Patients with a diagnosis of an AUD who die from injury differ significantly from those who die from other medical conditions. Prevention and intervention programs could focus separately upon selected groups with increased risk for injury or non-injury-related death.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79146/1/j.1360-0443.2010.03024.x.pd

QoS management and control for an all-IP WiMAX network architecture: Design, implementation and evaluation

The IEEE 802.16 standard provides a specification for a fixed and mobile broadband wireless access system, offering high data rate transmission of multimedia services with different Quality-of-Service (QoS) requirements through the air interface. The WiMAX Forum, going beyond the air interface, defined an end-to-end WiMAX network architecture, based on an all-IP platform in order to complete the standards required for a commercial rollout of WiMAX as broadband wireless access solution. As the WiMAX network architecture is only a functional specification, this paper focuses on an innovative solution for an end-to-end WiMAX network architecture offering in compliance with the WiMAX Forum specification. To our best knowledge, this is the first WiMAX architecture built by a research consortium globally and was performed within the framework of the European IST project WEIRD (WiMAX Extension to Isolated Research Data networks). One of the principal features of our architecture is support for end-to-end QoS achieved by the integration of resource control in the WiMAX wireless link and the resource management in the wired domains in the network core. In this paper we present the architectural design of these QoS features in the overall WiMAX all-IP framework and their functional as well as performance evaluation. The presented results can safely be considered as unique and timely for any WiMAX system integrator

Transcriptome pathways unique to dehydration tolerant relatives of modern wheat

Among abiotic stressors, drought is a major factor responsible for dramatic yield loss in agriculture. In order to reveal differences in global expression profiles of drought tolerant and sensitive wild emmer wheat genotypes, a previously deployed shock-like dehydration process was utilized to compare transcriptomes at two time points in root and leaf tissues using the Affymetrix GeneChip(R) Wheat Genome Array hybridization. The comparison of transcriptomes reveal several unique genes or expression patterns such as differential usage of IP(3)-dependent signal transduction pathways, ethylene- and abscisic acid (ABA)-dependent signaling, and preferential or faster induction of ABA-dependent transcription factors by the tolerant genotype that distinguish contrasting genotypes indicative of distinctive stress response pathways. The data also show that wild emmer wheat is capable of engaging known drought stress responsive mechanisms. The global comparison of transcriptomes in the absence of and after dehydration underlined the gene networks especially in root tissues that may have been lost in the selection processes generating modern bread wheats

Applications of Two-Body Dirac Equations to the Meson Spectrum with Three versus Two Covariant Interactions, SU(3) Mixing, and Comparison to a Quasipotential Approach

In a previous paper Crater and Van Alstine applied the Two Body Dirac equations of constraint dynamics to the meson quark-antiquark bound states using a relativistic extention of the Adler-Piran potential and compared their spectral results to those from other approaches, ones which also considered meson spectroscopy as a whole and not in parts. In this paper we explore in more detail the differences and similarities in an important subset of those approaches, the quasipotential approach. In the earlier paper, the transformation properties of the quark-antiquark potentials were limited to a scalar and an electromagnetic-like four vector, with the former accounting for the confining aspects of the overall potential, and the latter the short range portion. A part of that work consisted of developing a way in which the static Adler-Piran potential was apportioned between those two different types of potentials in addition to covariantization. Here we make a change in this apportionment that leads to a substantial improvement in the resultant spectroscopy by including a time-like confining vector potential over and above the scalar confining one and the electromagnetic-like vector potential. Our fit includes 19 more mesons than the earlier results and we modify the scalar portion of the potential in such a way that allows this formalism to account for the isoscalar mesons {\eta} and {\eta}' not included in the previous work. Continuing the comparisons made in the previous paper with other approaches to meson spectroscopy we examine in this paper the quasipotential approach of Ebert, Faustov, and Galkin for a comparison with our formalism and spectral results.Comment: Revisions of earlier versio

A CAM- and starch-deficient mutant of the facultative CAM species Mesembryanthemum crystallinum reconciles sink demands by repartitioning carbon during acclimation to salinity

In the halophytic species Mesembryanthemum crystallinum, the induction of crassulacean acid metabolism (CAM) by salinity requires a substantial investment of resources in storage carbohydrates to provide substrate for nocturnal CO2 uptake. Acclimation to salinity also requires the synthesis and accumulation of cyclitols as compatible solutes, maintenance of root respiration, and nitrate assimilation. This study assessed the hierarchy and coordination of sinks for carbohydrate in leaves and roots during acclimation to salinity in M. crystallinum. By comparing wild type and a CAM-/starch-deficient mutant of this species, it was sought to determine if other metabolic sinks could compensate for a curtailment in CAM and enable acclimation to salinity. Under salinity, CAM deficiency reduced 24 h photosynthetic carbon gain by >50%. Cyclitols were accumulated to comparable levels in leaves and roots of both the wild type and mutant, but represented only 5% of 24 h carbon balance. Dark respiration of leaves and roots was a stronger sink for carbohydrate in the mutant compared with the wild type and implied higher maintenance costs for the metabolic processes underpinning acclimation to salinity when CAM was curtailed. CAM required the nocturnal mobilization of >70% of primary carbohydrate in the wild type and >85% of carbohydrate in the mutant. The substantial allocation of carbohydrate to CAM limited the export of sugars to roots, and the root:shoot ratio declined under salinity. The data suggest a key role for the vacuole in regulating the supply and demand for carbohydrate over the day/night cycle in the starch-/CAM-deficient mutant

Protease inhibitors of Manduca sexta expressed in transgenic cotton

To explore the effectiveness of insect derived protease inhibitors in protecting plants against insect feeding, anti-trypsin, anti-chymotrypsin and anti-elastase protease inhibitor (PI) genes from Manduca sexta L. were expressed in transgenic cotton ( Gossypium hirsutum L.). From 198 independent transformants, 35 elite lines were further analyzed. Under the control of the 35S promoter of CaMV, PI accumulated to approximately 0.1% of total protein, depending on the tissue analyzed. Using cell-flow cytometry, DNA content/ nuclei of transgenic and non-transformed cotton were identical. On cotton plants expressing PIs, fecundity of Bemisia tabaci (Genn.), the sweetpotato whitefly, was reduced compared to controls. Expression of these protease inhibitors may reduce the developmental rate of B. tabaci and other insects, and provide a strategy for cotton protection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46980/1/299_2004_Article_BF00232917.pd