The Lantern Vol. 32, No. 1, January 1965

• The Wise Man • Of Men and Lobsters • Deliberate-Beyond Conception • Villanelle • Villanelle: Interlude • Rune Green Stones • Redemption • John Ten • Torch Ends • The General and the Birdnest • Not Quite Free • Hymn to the Morning • Walking Togetherhttps://digitalcommons.ursinus.edu/lantern/1087/thumbnail.jp

Variable sizes of Escherichia coli chemoreceptor signaling teams

Like many sensory receptors, bacterial chemotaxis receptors form clusters. In bacteria, large-scale clusters are subdivided into signaling teams that act as ‘antennas' allowing detection of ligands with remarkable sensitivity. The range of sensitivity is greatly extended by adaptation of receptors to changes in concentrations through covalent modification. However, surprisingly little is known about the sizes of receptor signaling teams. Here, we combine measurements of the signaling response, obtained from in vivo fluorescence resonance energy transfer, with the statistical method of principal component analysis, to quantify the size of signaling teams within the framework of the previously successful Monod–Wyman–Changeux model. We find that size of signaling teams increases 2- to 3-fold with receptor modification, indicating an additional, previously unrecognized level of adaptation of the chemotaxis network. This variation of signaling-team size shows that receptor cooperativity is dynamic and likely optimized for sensing noisy ligand concentrations

Consumer Sensory Evaluation of Ground Beef and Plant-Based Ground Beef Alternatives Used in a Hamburger Application

Objective: The objective of this study was to evaluate the palatability traits and consumer acceptance of three plant-based ground beef alternatives in comparison to ground beef in a foodservice-like hamburger application. Study Description: Three popular plant-based ground beef alternatives (GBA) and 80% lean, 20% fat composition ground beef chubs (n = 20) were selected for consumer analysis. Samples were cooked to an internal temperature of 160°F, plated on a bun and served to consumers with the opportunity to apply ketchup, mustard, cheese, lettuce, and pickles. Consumers evaluated the differences in palatability traits and purchase intent for the samples identified as: Ground Beef, Foodservice GBA, Retail GBA, and Traditional GBA. The Bottom Line: This research indicates the use of ground beef and ground beef alternatives provide different eating experiences when consumed as a complete hamburger and should be marketed as such by the foodservice and retail sectors

Consumer Sensory Evaluation of Ground Beef and Plant-Based Ground Beef Alternatives Used in a Taco Application

Objective: The objective of this study was to evaluate consumer preferences for palatability traits and consumer acceptability of three plant-based protein alternatives and ground beef in a taco application. Study Description: Three commercially available plant-based ground beef alternative (GBA) treatments (n = 20) were selected based upon industry prevalence. The GBAs’ were identified as the most popular in the marketing sectors of foodservice (FGBA), retail (RGBA), and traditional (TGBA). One ground beef (80% lean; 20% fat) treatment (n = 20) was selected. Samples were crumbled into a skillet and cooked to a surface temperature of 180°F. Following cooking, a generic taco seasoning was added following manufacturer’s instruction. Samples were served on a flour tortilla with the opportunity to add cheese, lettuce, and tomatoes. The Bottom Line: This research indicates consumers preferred ground beef to ground beef alternatives when used as a crumbled protein ingredient in tacos. Ground beef should be marketed as a distinct eating experience to consumers at foodservice and retail when plant-based ground beef alternatives are available in similar crumbled products

Evaluation of Kansas Beef Consumers’ Awareness and Understanding of Business-to-Consumer Marketing

Objective: The objective of the study was to determine the understanding and knowledge level of consumers purchasing beef in a business-to-consumer (B2C) format within Kansas. Study Description: A digital survey was created to evaluate consumers’ familiarity and satisfaction of buying beef in a B2C format. The survey was made available for a two-week period to consumers utilizing the Shop Kansas Farms online social media group. Results: Results of the survey showed 93% of consumers (n = 174) reported having previously purchased beef products from a local producer or locker. Of these, 63.1% reported that their most recent purchase was their first time purchasing in a B2C format and the same percentage of consumers had been purchasing beef in a B2C format for less than five years. The most common methods of purchasing beef in a B2C format were “portion cuts” (24.5%), followed by “quarter beef” (17.0%) and “half beef” (15.1%), or a combination of at least two of these methods (20.7%). Only 5.7% of consumers experienced challenges while purchasing beef in a B2C format, yet 100% of those consumers still intended to continue purchasing beef in this format. When consumers were given options that would be useful to prevent future complaints, the most selected response was “improved consumer knowledge.” The consumers (n = 82) who rated this response as “very effective” or “extremely effective” indicated that “increased state extension resources” would be at least “moderately effective” (82.9%). This indicates that increased state extension resources would be an effective way to improve consumer knowledge. The Bottom Line: Consumers within the state of Kansas are interested in and have positive experiences with purchasing beef in the B2C format. Moreover, most consumers are new consumers to buying beef in the B2C format, indicating that there is increasing demand for beef available for purchase in this format. Results of this study support this but show room for growth within consumer understanding of purchasing beef in a B2C format. Results of this study shows the opportunity for improvement of extension and other resources for consumers

Determination of Consumer Color and Discoloration Thresholds for Purchase of Retail Ground Beef When Evaluating Multiple Days of Display Simultaneously

Objective: The objective of this study was to identify the threshold for color and discoloration for consumers to purchase ground beef in a simulated retail display and to determine the best objective measurement to predict consumer purchase intent. Study Description: For this study, 180 1-lb 80% lean/20% fat ground beef packages were assigned to a day of retail display (day 0–9). Consumers (n = 216) and trained descriptive panelists evaluated ground beef samples from each day of display simultaneously. Instrumental L* (lightness), a* (redness), and b* (yellowness) values were collected, and spectral data were recorded. Logistic and simple linear regression models were calculated for consumer likelihood to purchase and appearance ratings. Pearson correlation coefficients were calculated for all measurements. The Bottom Line: The models generated from this study provide the ability to predict consumer willingness to purchase ground beef of varying days of retail display and provide ground beef producers an indication of potential consumer purchasing behaviors based upon objective values that are easy to measure

Consumer Color and Discoloration Thresholds for Purchase of Retail Ground Beef When Evaluating Packages of a Single Day of Display

Objective: This study utilized a simulated retail display to investigate the impact of ground beef color and discoloration on consumer purchase intent, while identifying the best objective measurements to predict consumer preferences of ground beef on the same day of retail display. Study Description: For this study, 180 1-lb 80% lean/20% fat ground beef loaves were assigned to a specific day of retail display (day 0–9). Consumers (n = 318) and trained descriptive panelists assessed ground beef samples, with a single day of display evaluated per consumer group. Spectral data and L* (lightness), a* (redness), and b* (yellowness) values were collected. Simple linear and logistic regressions were calculated for consumer ratings. Lastly, Pearson correlation coefficients were calculated for sensory and objective measurements. The Bottom Line: Consumer intent to purchase ground beef at varying days of retail display can be predicted by the objective measures used in this study. Moving forward, these models can provide ground beef producers and retailers with an indication of potential consumer purchasing behaviors for ground beef at varying levels of discoloration to prevent waste and maximize profits

Overview of mathematical approaches used to model bacterial chemotaxis I: the single cell

Mathematical modeling of bacterial chemotaxis systems has been influential and insightful in helping to understand experimental observations. We provide here a comprehensive overview of the range of mathematical approaches used for modeling, within a single bacterium, chemotactic processes caused by changes to external gradients in its environment. Specific areas of the bacterial system which have been studied and modeled are discussed in detail, including the modeling of adaptation in response to attractant gradients, the intracellular phosphorylation cascade, membrane receptor clustering, and spatial modeling of intracellular protein signal transduction. The importance of producing robust models that address adaptation, gain, and sensitivity are also discussed. This review highlights that while mathematical modeling has aided in understanding bacterial chemotaxis on the individual cell scale and guiding experimental design, no single model succeeds in robustly describing all of the basic elements of the cell. We conclude by discussing the importance of this and the future of modeling in this area

Impact of Disclosing Fat Content on Consumer Sensory Evaluation of Ground Beef From a Similar Source

Objective: The objective of this study was to determine the impact of providing consumers with information regarding the fat content of ground beef on the consumer’s eating experience. Study Description: Ground beef chubs that were 80% lean/20% fat (n = 15/panel type) were obtained, and 0.25-lb patties were fabricated from the chubs. Chubs were assigned randomly to panels. Panelists received samples labeled as the following: 90% lean/10% fat (90/10), 80% lean/20% fat (80/20), 73% lean/27% fat (73/27), lean, extra lean, and one sample with no information given (NONE). Samples were evaluated by consumers (n = 105), who were provided information regarding treatment labels prior to evaluation, on 0- to 100-point line scales for tenderness, juiciness, flavor, texture overall liking, and purchasing intent. Consumers also rated each trait as acceptable or unacceptable. Ground beef with 90/10, 80/20, and 73/27 labels resulted in a large increase (P \u3c 0.05) in consumer ratings for tenderness, flavor, and overall liking. The Bottom Line: Presenting information regarding fat content to consumers influenced perceived palatability of ground beef. Today’s consumers are paying closer attention to labeling statements than in the past. Results from this study support this trend, indicating consumers’ eating experiences are affected by the fat content labeling found on ground beef packages. Ground beef marketing decisions should consider the information incorporated on packaging, including fat content, as there is an impact on consumers’ palatability experience

Transmission electron microscopy characterization of fluorescently labelled amyloid β 1-40 and α-synuclein aggregates

<p>Abstract</p> <p>Background</p> <p>Fluorescent tags, including small organic molecules and fluorescent proteins, enable the localization of protein molecules in biomedical research experiments. However, the use of these labels may interfere with the formation of larger-scale protein structures such as amyloid aggregates. Therefore, we investigate the effects of some commonly used fluorescent tags on the morphologies of fibrils grown from the Alzheimer's disease-associated peptide Amyloid β 1-40 (Aβ40) and the Parkinson's disease-associated protein α-synuclein (αS).</p> <p>Results</p> <p>Using transmission electron microscopy (TEM), we verify that N-terminal labeling of Aβ40 with AMCA, TAMRA, and Hilyte-Fluor 488 tags does not prevent the formation of protofibrils and amyloid fibrils of various widths. We also measure the two-photon action cross-section of Aβ40 labelled with Hilyte Fluor 488 and demonstrate that this tag is suitable for use with two-photon fluorescence techniques. Similarly, we find that Alexa Fluor 488 labelling of αS variant proteins near either the N or C terminus (position 9 or 130) does not interfere with the formation of amyloid and other types of αS fibrils. We also present TEM images of fibrils grown from αS C-terminally labelled with enhanced green fluorescent protein (EGFP). Near neutral pH, two types of αS-EGFP fibrils are observed via TEM, while denaturation of the EGFP tag leads to the formation of additional species.</p> <p>Conclusions</p> <p>We demonstrate that several small extrinsic fluorescent tags are compatible with studies of amyloid protein aggregation. However, although fibrils can be grown from αS labelled with EGFP, the conformation of the fluorescent protein tag affects the observed aggregate morphologies. Thus, our results should assist researchers with label selection and optimization of solution conditions for aggregation studies involving fluorescence techniques.</p