2,150 research outputs found
Chronic-moderate ethanol exposure of L(tk-) cells expressing ? 4? 3? GABAA receptors reduces potency of allopregnanolone potentiation of GABA-evoked inward currents: Possible role of PKC
Aim: To investigate the effect of chronic-moderate ethanol (CME) treatment upon direct activation and allosteric modulation of GABAA receptors, and to assess the sensitivity of these parameters to PKC inhibition in control and ethanol-treated cells.
Methods: L(tk-) cells were exposed to 20mM ethanol in culture media for 14 days prior to induction of stable expression of human recombinant ?4?3? receptors using dexamethasone. Concentration-response curves for GABA (1nM - 100µM), and allopregnanolone (ALLO; 1nM - 30µM) co-applied with 200nM GABA were obtained using whole-cell patch-clamp electrophysiology at a holding voltage of -60 mV. 400nM calphostin C (CphC) or vehicle (DMSO) was administered to cells via the pipette solution, which was prepared with 2mM Mg.ATP. SDS-PAGE and western blotting were used to compare levels of whole-cell expression, quantified relative to ?-actin, of ?4 and ? GABAA receptor subunits, and several isoforms of PKC (?, ?, ?, and ?), in control and CME-treated cells. Data was reported as Mean ± SEM and significance determined by either one-way ANOVA with Newman-Keuls multiple comparison tests, or two-way, unpaired t-tests.
Results: Expression of ?4 subunits was reduced 35% (P0.05) and pEC50 (control: 6.18±0.04, n=13, CME: 6.17±0.04, n=4, P>0.05) of GABA were unchanged. CphC increased the GABA pEC50 relative to control (6.62±0.08, n=3, P<0.001) but had no effect upon responses at pEC20 GABA. Following CME, the potency of GABA was unaltered in the presence of CphC.
The magnitude of ALLO-induced potentiation in control cells (7.34±0.6 fold, n=19) was unchanged by CME (ATP: 7.39±1.0 fold, n=9, P>0.05), and CphC had no significant effect in control or CME-treated cells.
The ALLO pEC50 in control cells (6.23±0.05, n=19) was unaffected by CphC. Following CME, the potency of ALLO was reduced (5.68±0.06, n=9, P<0.001) but was enhanced in the presence of CphC, which restored potency almost back to control levels (5.94±0.09, n=5, P<0.05 relative to control).
Expression of the ?, ?, ?, and ? isoforms of PKC was detected in whole-cell lysates of L(tk-) cells but only PKC? was significantly altered by CME treatment, exhibiting a nearly 4-fold increase (3.9±0.47 fold P<0.01) when compared with that in controls.
Discussion: CME of un-induced L(tk-) cells was sufficient to alter sensitivity of ?4?3? receptor function to alterations of the balance of phosphorylation induced by CphC. The increased expression of PKC? after CME may have been directly related to the absence of effect of CphC upon GABA potency. As direct interaction of GABAA receptors with PKC? has not been determined, the effects observed for potency and efficacy of ALLO following CME may be indicative of changes to the phosphorylation of accessory proteins or other PKC isoforms by PKC?
Dynamic Metric Learning from Pairwise Comparisons
Recent work in distance metric learning has focused on learning
transformations of data that best align with specified pairwise similarity and
dissimilarity constraints, often supplied by a human observer. The learned
transformations lead to improved retrieval, classification, and clustering
algorithms due to the better adapted distance or similarity measures. Here, we
address the problem of learning these transformations when the underlying
constraint generation process is nonstationary. This nonstationarity can be due
to changes in either the ground-truth clustering used to generate constraints
or changes in the feature subspaces in which the class structure is apparent.
We propose Online Convex Ensemble StrongLy Adaptive Dynamic Learning (OCELAD),
a general adaptive, online approach for learning and tracking optimal metrics
as they change over time that is highly robust to a variety of nonstationary
behaviors in the changing metric. We apply the OCELAD framework to an ensemble
of online learners. Specifically, we create a retro-initialized composite
objective mirror descent (COMID) ensemble (RICE) consisting of a set of
parallel COMID learners with different learning rates, demonstrate RICE-OCELAD
on both real and synthetic data sets and show significant performance
improvements relative to previously proposed batch and online distance metric
learning algorithms.Comment: to appear Allerton 2016. arXiv admin note: substantial text overlap
with arXiv:1603.0367
Competencies of the twenty-first century superstore manager: Implications for professional postsecondary education
In recent years, supermarkets have become more complex and challenging to operate. Many supermarkets offer an expanded selection of products and services not found in the traditional format. These new generation supermarkets have been labeled by the Food Marketing Institute (FMI) as superstores. The purpose of this study was to identify a competency model needed to successfully operate a superstore over the next 5-10 years. In addition, the study sought to identify the core competencies that formulate the superstore competency model and to compare the results of the model to the Contemporary Store Manager Model which was created from a similar study conducted in 1984. The Contemporary Store Manager Model identified three distinct roles of the 1984 contemporary store manager. These roles were culture builder, local strategist, and computer-assisted analyst. The findings presented in this study can provide a blueprint for professional development programs established by the retail food industry and higher education.;This study utilized three panels of experts to generate and validate the core competencies required to be successful in a superstore over the next 5-10 years. The first panel consisted of eight superstore managers from Ukrop\u27s Super Markets who were rated as outstanding performers. This group generated the initial pool of core competencies. The second panel consisted of 10 well-known supermarket industry experts. These individuals rated the initial pool of competencies created by the superstore managers. The third panel of experts consisted of 29 senior leaders from the most innovative supermarkets in the United States. These individuals rated the results of the second panel. The final pool of core competencies was clustered by the panel of superstore managers to create the Superstore Competency Model.;The Superstore Manager Competency Model consists of 46 core competencies bundled into four clusters. The clusters include the ambassador, the educator, the technician, and the futurist The four clusters identified in this model are generally consistent with the roles identified in the Contemporary Store Manager Model. The new model provides greater clarity in terms of the core competencies.;The Superstore Competency Model can be utilized by the supermarket industry as well as the field of higher education to build curriculums targeted to the professional development of the superstore manager. These curriculums could involve undergraduate degrees, certificates, and non-credit seminars. Further research could focus on using the results to build superstore manager selection systems
Current Perspective on the Location and Function of Gamma- Aminobutyric Acid (GABA) and its Metabolic Partners in the Kidney.
Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter located in the mammalian central nervous system, which binds to GABAA and GABAB receptors to mediate its neurological effects. In addition to its role in the CNS, an increasing number of publications have suggested that GABA might also play a role in the regulation of renal function. All three enzymes associated with GABA metabolism; glutamic acid decarboxylase, GABA ?-oxoglutarate transaminase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH) have been localised to the kidney providing the necessary machinery for localised GABA synthesis and metabolism. Moreover GABA receptors have been localised to both tubular and vascular structures in the kidney, and GABA is excreted in urine (~3 ?M) in humans. Despite the collective evidence describing the presence of a GABA system in the kidney, the precise function of such a system requires further clarification. Here we provide an overview of the current renal GABA literature and provide novel data that indicates GABA can act at contractile pericyte cells located along vasa recta capillaries in the renal medulla to potentially regulate medullary blood flow
Quinine blocks 5-HT and 5-HT3 receptor mediated peristalsis in both guinea pig and mouse ileum tissue
Introduction. Quinine is commonly used to treat malaria; however one of the principal side effects is gastrointestinal disturbances (White, 1992). 5-HT3 receptors modulate gut peristalsis (Chetty et al., 2006), and, as quinine has been shown to act as a 5-HT3 receptor antagonist (Thompson and Lummis, 2008) it is possible that these side effects result from actions at gut 5-HT3 receptors. To address this question, we examined the ability of quinine to antagonise 5-HT and 5-HT3 mediated peristalsis in guinea pig and mouse ileum.
Methods. Ileum was excised from male guinea pigs (200-300g) and C57BL/6 mice (25-35g) following cervical dislocation. Ileum segments (3-5 cm) were mounted in 50 ml organ baths containing Tryode’s solution at 35-37 °C. Concentration-response curves were constructed for 5-HT and the selective 5-HT3 agonist 2-Me-5-HT (non-cumulative doses). Quinine was pre-applied for 10 min and inhibition measured using agonist concentrations that elicited a submaximal response.
Results. Concentration-dependent contractions produced by 5-HT (pEC50 = 5.45 ± 0.17, n = 8) and the selective 5-HT3 agonist 2-Me-5-HT (5.01 ± 0.17, n = 11) were not significantly different (Student’s t-test, t = 0.619, df = 17, p = 0.544) in guinea pig ileum. Increasing concentrations of quinine were able to antagonise the activities of both 5-HT (pIC50 = 5.03 ± 0.2, n = 6) and 2-Me-5HT (pIC50 = 4.59 ± 0.26, n = 4). At mouse ileum, 5-HT (pEC50 = 7.57 ± 0.33, n = 9) was more potent (Student’s t-test, t = 3.6, df = 12, p = 0.004) than 2-Me-5-HT (pEC50 = 5.45 ± 0.58, n = 5). Quinine antagonised both the 5-HT (pIC50 = 4.87 ± 0.31, n = 7) and 2-Me-5-HT-induced (pIC50 = 6.18 ± 1.14, n = 4) contractions.
Conclusions. These results support previous electrophysiological studies that identified quinine as an antagonist at recombinant 5-HT3 receptors with IC50 values comparable with those reported here (pIC50 = 4.87, Thompson et al., 2007). Further, we found that quinine completely blocked 5-HT induced contractions in mouse and guinea pig, raising the possibility that quinine targets other 5-HT receptors in the gut (e.g., 5-HT4 receptors) and may influence intestinal function
Permanent Draft Genome Sequence of Frankia sp. Strain AvcI1, a Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Alnus viridis subsp. crispa Grown in Canada
Frankia strain AvcI1, isolated from root nodules of Alnus viridis subsp. crispa, is a member of Frankia lineage Ia, which is able to reinfect plants of the Betulaceae and Myricaceae families. Here, we report a 7.7-Mbp draft genome sequence with a G+C content of 72.41% and 6,470 candidate protein-encoding genes
Permanent Draft Genome Sequence of Frankia sp. Strain ACN1ag, a Nitrogen-Fixing Actinobacterium Isolated from the Root Nodules of Alnus glutinosa
Frankia strain ACN1ag is a member of Frankia lineage Ia, which are able to re-infect plants of the Betulaceae and Myricaceae families. Here, we report a 7.5-Mbp draft genome sequence with a G+C content of 72.35% and 5,687 candidate protein-encoding genes
The Oneida County 4-H Conservation Field Days Conflict
In its 30-year history, New York\u27s Oneida County 4-H Conservation Education Field Days program generated no known controversy. That trend changed radically when a citizens group shot undercover video footage portraying the event as children being brainwashed into thinking guns, hunting and trapping are okay. The video aired statewide and resulted in a national controversy. Oneida County 4-H responded by trying to build consensus among the organizations involved, but discovered that this was not possible. This article relates the events that precipitated this conflict, and examines the various perspectives on the conflict held by the three major organizations involved
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