A BIOASSAY OF MONTANA GRASSLAND PLANT RESISTANCE TO CATECHIN: AN EXUDATE OF SPOTTED KNAPWEED, CENTAUREA MACULOSA

Centaurea maculosa, or Spotted knapweed, is considered an invasive species in the Western United States, including Montana. It has established sizeable populations and displaced native plant communities through what is believed to be a result of the plant’s exudate, catechin. Catechin is an allelochemical documented to have phytotoxic, antimicrobial, and chelating properties. Current methods of remediation (biological, mechanical, and chemical) have demonstrated limited degrees of success. It is hypothesized that the degree of resistance to catechin of neighboring plant species determines the degree of knapweed invasiveness. The goal of this research is to test Montana native grassland species for resistance to catechin. Assembling a bioassay on agar plates, Montana grassland seeds will be grown in the presence and absence of catechin.  The degree of resistance for each respective grassland species will be assessed through percent germination, root length, and shoot length. In identifying a Montana native grassland species with catechin resistance, the species could provide potential means of remediation and prevention

Screening Montana Native Grass Species for Resitance to Spotted Knapweed Exudate Catechin (Poster)

It has been reported that catechin is an exudate of spotted knapweed (Centaurea maculosa). Documented to have chelating, antimicrobial and phytotoxic properties, catechin is believed to contribute to spotted knapweed’s ability to displace native plant communities. Originating in Europe, it is considered an invasive species in the Western United States and is recorded to have established populations in all fifty-six counties in Montana. Select plant species in Europe have demonstrated resistance to catechin without community displacement. It is hypothesized that the degree of resistance to catechin of neighboring plant species determines the degree of knapweed invasiveness.  Using agar plates and several Montana grassland species, a bioassay was created to assess the degree of resistance of native grassland seeds to catechin. Assessed through percent germination, root length, and shoot length, the degree of resistance for each species was assessed. Identifying a Montana native grassland species with catechin resistance could provide potential means for knapweed prevention

A mechanistic inter-species comparison of flicker sensitivity

AbstractThe general validity of both the Rovamo [Vision Res. 39 (1999) 533] and Barten (Contrast sensitivity of the human eye, SPIE Optical Engineering Press, 1999), modulation transfer function models for describing flicker sensitivity in vertebrates was examined using published data for goldfish, chickens, tree shrews, ground squirrels, cats, pigeons and humans. Both models adequately described the flicker response in each species at frequencies greater than approximately 1 Hz. At lower frequencies, response predictions differed between the two models and this was due, in part, to dissimilar definitions of the role played by lateral inhibition in the retina. Modelled flicker sensitivity for a matched retinal illuminance condition enabled a direct inter-species comparison of signal processing response times at the photoreceptor level. The modelled results also quantified differences between species in post-retinal signal processing capability. Finally, the relationship between flicker frequency response curves and the perception of temporal signals in real visual scenes was examined for each species. It is proposed that the area under the flicker sensitivity function may offer a single “figure of merit” for specifying overall sensitivity to time signals in a species’ environment

Management Research that Makes a Difference:Broadening the Meaning of Impact

The world is undergoing dramatic transformations. Many of the grand societal challenges we currently face underscore the need for scholarly research – including management studies – that can help us best sort out and solve them. Yet, management scholars struggle to produce concrete solutions or to communicate how their research can help to tackle these grand societal challenges. With this editorial, we want to help scholars seeking to ‘make a difference’ by broadening our understanding of what constitutes impactful research. We examine five forms of impact – scholarly, practical, societal, policy, and educational – outlining how scholars can systematically extend or enlarge their research agenda or projects to amplify their impact on the challenges societies face. We suggest that each of these forms of impact has intrinsic value in advancing the scientific enterprise and, together, can help to address key societal problems that reach beyond the immediate and traditional context of business management. With concrete suggestions for getting started on these forms of impact, and possible outputs for each, we hope to stimulate management and organization scholars to think more broadly about the opportunities for making an impact with their research and to begin doing so more often

Interaction of the human respiratory Syncytial virus matrix protein with cellular adaptor protein complex 3 plays a critical role in trafficking

Human Respiratory Syncytial Virus (HRSV) is a leading cause of bronchopneumonia in infants and the elderly. To date, knowledge of viral and host protein interactions within HRSV is limited and are critical areas of research. Here, we show that HRSV Matrix (M) protein interacts with the cellular adaptor protein complex 3 specifically via its medium subunit (AP-3Mu3A). This novel protein-protein interaction was first detected via yeast-two hybrid screen and was further confirmed in a mammalian system by immunofluorescence colocalization and co-immunoprecipitation. This novel interaction is further substantiated by the presence of a known tyrosine-based adaptor protein MU subunit sorting signal sequence, YXXФ: where Ф is a bulky hydrophobic residue, which is conserved across the related RSV M proteins. Analysis of point-mutated HRSV M derivatives indicated that AP-3Mu3A- mediated trafficking is contingent on the presence of the tyrosine residue within the YXXL sorting sequence at amino acids 197-200 of the M protein. AP-3Mu3A is up regulated at 24 hours post-infection in infected cells versus mock-infected HEp2 cells. Together, our data suggests that the AP-3 complex plays a critical role in the trafficking of HRSV proteins specifically matrix in epithelial cells. The results of this study add new insights and targets that may lead to the development of potential antivirals and attenuating mutations suitable for candidate vaccines in the future

A Framework for Studying Synaptic Plasticity with Neural Spike Train Data

Learning and memory in the brain are implemented by complex, time-varying changes in neural circuitry. The computational rules according to which synaptic weights change over time are the subject of much research, and are not precisely understood. Until recently, limitations in experimental methods have made it challenging to test hypotheses about synaptic plasticity on a large scale. However, as such data become available and these barriers are lifted, it becomes necessary to develop analysis techniques to validate plasticity models. Here, we present a highly extensible framework for modeling arbitrary synaptic plasticity rules on spike train data in populations of interconnected neurons. We treat synaptic weights as a (potentially nonlinear) dynamical system embedded in a fully-Bayesian generalized linear model (GLM). In addition, we provide an algorithm for inferring synaptic weight trajectories alongside the parameters of the GLM and of the learning rules. Using this method, we perform model comparison of two proposed variants of the well-known spike-timing-dependent plasticity (STDP) rule, where nonlinear effects play a substantial role. On synthetic data generated from the biophysical simulator NEURON, we show that we can recover the weight trajectories, the pattern of connectivity, and the underlying learning rules.Engineering and Applied Science

Is routine pathological examination required in South African children undergoing adenotonsillectomy?

Objective We aimed to determine the incidence of abnormal pathologic findings in the tonsils and/ or adenoids of children undergoing tonsillectomy +/- adenoidectomy; incidence of tuberculosis of the tonsils and adenoids, and suggest criteria to identify children at risk for adenotonsillar tuberculosis; association between HIV and adenotonsillar abnormality; and the cost-effectiveness of routine pathological examination of adenotonsillectomy specimens, and criteria to decide which specimens to send for histology. Methods This was an 8 month prospective study on all children (≤ 12 years) undergoing consecutive tonsillectomy or adenotonsillectomy (T&A) at Red Cross War Memorial Children’s’ Hospital (RCH). Patients were assessed pre-operatively and tonsil sizes graded pre- and intra-operatively. Blood was taken for HIV testing and all tonsils and adenoids had histological examinations. A cost-benefit analysis was done to determine the cost- effectiveness of adeno- tonsillectomy routine pathology. Results A total of 344 tonsils were analysed on 172 children (102 males, 70 females); one patient had nasopharyngeal tuberculosis and another lymphoma of the tonsils; 13 (7.6%) patients had clinically asymmetrically enlarged tonsils but no significant abnormal pathological finding. The average charge to detect a clinically significant abnormality was R22 744 (R45 488 ÷ 2 abnormalities). Conclusions The following criteria could improve cost-effectiveness of pathological examination of adenotonsillectomy specimens: positive tuberculosis contact in the house, systemic symptoms of fever and weight loss, cervical lymphadenopathy >3cm, suspicious nasopharyngeal appearance, HIV positive patients, rapid tonsillar enlargement or significant tonsillar asymmetry. On our evidence routine pathology on South African children does not seem to be justified

Investigating the NPY/AgRP/GABA to GnRH neuron circuit in prenatally androgenized PCOS-like mice

Polycystic ovary syndrome (PCOS), the most common form of anovulatory infertility, is associated with altered signaling within the hormone-sensitive neuronal network that regulates gonadotropin-releasing hormone (GnRH) neurons, leading to a pathological increase in GnRH secretion. Circuit remodeling is evident between GABAergic neurons in the arcuate nucleus (ARN) and GnRH neurons in a murine model of PCOS. One-third of ARN GABA neurons co-express neuropeptide Y (NPY), which has a known yet complex role in regulating GnRH neurons and reproductive function. Here, we investigated whether the NPY-expressing subpopulation (NPYARN) of ARN GABA neurons (GABAARN) is also affected in prenatally androgenized (PNA) PCOS-like NPYARN reporter mice [Agouti-related protein (AgRP)-Cre;τGFP]. PCOS-like mice and controls were generated by exposure to di-hydrotestosterone or vehicle (VEH) in late gestation. τGFP-expressing NPYARN neuron fiber appositions with GnRH neurons and gonadal steroid hormone receptor expression in τGFP-expressing NPYARN neurons were assessed using confocal microscopy. Although GnRH neurons received abundant close contacts from τGFP-expressing NPYARN neuron fibers, the number and density of putative inputs was not affected by prenatal androgen excess. NPYARN neurons did not co-express progesterone receptor or estrogen receptor α in either PNA or VEH mice. However, the proportion of NPYARN neurons co-expressing the androgen receptor was significantly elevated in PNA mice. Therefore, NPYARN neurons are not remodeled by prenatal androgen excess like the wider GABAARN population, indicating GABA-to-GnRH neuron circuit remodeling occurs in a presently unidentified non-NPY/AgRP population of GABAARN neurons. NPYARN neurons do, however, show independent changes in the form of elevated androgen sensitivity

New Spirometry Indices for Detecting Mild Airflow Obstruction.

The diagnosis of chronic obstructive pulmonary disease (COPD) relies on demonstration of airflow obstruction. Traditional spirometric indices miss a number of subjects with respiratory symptoms or structural lung disease on imaging. We hypothesized that utilizing all data points on the expiratory spirometry curves to assess their shape will improve detection of mild airflow obstruction and structural lung disease. We analyzed spirometry data of 8307 participants enrolled in the COPDGene study, and derived metrics of airflow obstruction based on the shape on the volume-time (Parameter D), and flow-volume curves (Transition Point and Transition Distance). We tested associations of these parameters with CT measures of lung disease, respiratory morbidity, and mortality using regression analyses. There were significant correlations between FEV1/FVC with Parameter D (r = -0.83; p < 0.001), Transition Point (r = 0.69; p < 0.001), and Transition Distance (r = 0.50; p < 0.001). All metrics had significant associations with emphysema, small airway disease, dyspnea, and respiratory-quality of life (p < 0.001). The highest quartile for Parameter D was independently associated with all-cause mortality (adjusted HR 3.22,95% CI 2.42-4.27; p < 0.001) but a substantial number of participants in the highest quartile were categorized as GOLD 0 and 1 by traditional criteria (1.8% and 33.7%). Parameter D identified an additional 9.5% of participants with mild or non-recognized disease as abnormal with greater burden of structural lung disease compared with controls. The data points on the flow-volume and volume-time curves can be used to derive indices of airflow obstruction that identify additional subjects with disease who are deemed to be normal by traditional criteria