Methodological tests of the use of trace elements as tracers to assess root activity

peer-reviewedN.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).Background and aims There is increasing interest in how resource utilisation in grassland ecosystems is affected by changes in plant diversity and abiotic conditions. Research to date has mainly focussed on aboveground responses and there is limited insight into belowground processes. The aim of this study was to test a number of assumptions for the valid use of the trace elements caesium, lithium, rubidium and strontium as tracers to assess the root activity of several grassland species. Methods We carried out a series of experiments addressing the reliability of soil labelling, injection density, incubation time, application rate and the comparability of different tracers in a multiple tracer method. Results The results indicate that it is possible to achieve a reliable labelling of soil depths. Tracer injection density affected the variability but not the mean level of plant tracer concentrations. Tracer application rates should be based on pilot studies, because of site- and species-specific responses. The trace elements did not meet prerequisites to be used in a multiple tracer method. Conclusions The use of trace elements as tracers is potentially a very useful tool to give insight into plant root activity at different soil depths. This work highlights some of the main benefits and pitfalls of the method and provides specific recommendations to assist the design of tracer experiments and interpretation of the results.N.J.H. was funded by the Irish Research Council, co-funded by Marie Curie Actions under FP7. The field experiments A, B and G were supported by the European Community's Seventh Framework Programme (FP7/2007-2013) under the grant agreements FP7-266018 (AnimalChange) and FP7- 244983 (MultiSward). Experiment F was supported by the German Science Foundation (FOR 456).European Unio

Diacetyl and other Alpha-Dicarbonyl compounds with special reference to the flavor of butter

Diacetyl is an important flavor contributor of butter and various other foods. Similarity in chemical structure suggests that a number of other a-diketones would be similar in certain properties, including odor, to diacetyl, the simplest member of the series. Diacetyl and various homologs were synthesized long ago their reactions studied and certain similar chemical behaviors noted. However, the descriptions of the odors originally given would hardly suggest that diacetyl is involved in the flavor of certain foods. The work of van Niel, Kluyver and Derx (81) showed the importance of diacetyl as a flavor contributor of butter. Epstein and Harris (22-25) patented the use of certain a-diketones as flavoring materials for various foods. Taufel and Thaler (74) incidentally mentioned that in practice acetylpropionyl was sometimes used as a substitute for diacetyl

Evaluation of the Quality Characteristics of Premium Pork Loins

The objective of this study was to determine shear force, pH, marbling, color characteristics, percentage of intramuscular fat, and purge loss of pork loins from various premium brands in comparison to commodity products. Pork loins (n = 30/brand; Institutional Meat Purchasing Specifications #414) from five premium (PRE A, B, C, D, and E) and two commodity brands (COM A and B) were purchased from food service purveyors and commercial abattoirs. Loins were transported to the Kansas State University Meat Laboratory, Manhattan, KS, and allowed to age 14 to 15 days under refrigerated conditions (36 to 39°F) before fabrication. All PRE brands were similar (P \u3e 0.05) with lesser (P \u3c 0.05) slice shear force values than COM A, with the exception of PRE C, which had greater (P \u3c 0.05) slice shear force values than all other brands evaluated. Similar results were found for Warner-Bratzler shear force, with PRE C having greater (P \u3c 0.05) Warner-Bratzler shear force values than all other treatments, and no difference (P \u3e 0.05) found among the other PRE products. Commodity A was also tougher (P \u3c 0.05) than all PRE brands, except PRE C for Warner-Bratzler shear force. For subjective loin color evaluations, all PRE brands were similar (P \u3e 0.05), with only PRE C having a greater (P \u3c 0.05) color score than PRE B. Commodity B had a lesser (P \u3c 0.05) loin subjective color than all PRE products except PRE B and D. Also, COM B had a greater (P \u3c 0.05) L* value (lighter) and lesser (P \u3c 0.05) a* value (less red) than all of the other brands. No difference (P \u3e 0.05) in a* was found among the PRE brands and only PRE D and E differed (P \u3c 0.05) for L*. The two COM products had a similar (P \u3e 0.05) chop color score, however COM B was lighter (P \u3c 0.05) than all PRE brands. Premium A and E had greater loin visual marbling than all other brands, with no difference (P \u3e 0.05) found among the two COM brands and the other 3 PRE brands. However, for chop visual marbling, the two COM brands had less (P \u3c 0.05) marbling than all PRE brands, except PRE B and C. For fat percentage, all brands had between 2 to 3% fat, with COM A having less (P \u3c 0.05) fat than all PRE brands other than PRE B and D. Little variation was found among brands for pH, but COM B had a lower (P \u3c 0.05) pH than all of the other brands. Premium A, C, and D had less (P \u3c 0.05) weight lost as purge than any of the other brands. The differences observed within the quality traits evaluated show variation among different premium pork loin brands. This provides evidence that consumers and retailers will receive different levels of pork quality and eating satisfaction dependent upon the premium brand purchased

Effect of Degree of Doneness, Quality Grade, and Time on Instrumental Color Readings from Beef Strip Loin Steaks Cooked to Six Degrees of Doneness

Objective: The objective of this study was to determine the effect of quality grade and time after cooking on the instrumental color of steaks cooked to varying degrees of doneness. Study Description: Beef strip loins (n = 24) from 12 animals representing five quality treatments [Prime, Top Choice, Low Choice, Select, Select Enhanced (108%)] were collected. Each steak was cooked to a peak internal temperature of very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Each cooked steak was cut in half, perpendicular to the long axis of the steak, and lightness (L*), redness (a*), and yellowness (b*) was evaluated on the internal face of the medial side at 0, 1, 2, 3, 6, 9, and 12 minutes post-cutting using a Hunter Lab Miniscan spectrophotometer. The Bottom Line: The impact of time on internal cooked color was dependent on degree of doneness, with steaks cooked to lower degrees of doneness becoming lighter and more red in color with time and steaks cooked to higher degrees of doneness becoming darker. Additionally, quality treatment had no impact on cooked color measures of non-enhanced steaks. These results provide insight into cooked beef color changes related to time and how this might impact degree of doneness perceptions by consumers

Visual Degree of Doneness Has an Impact on Palatability Ratings of Consumers Who Had Differing Degree of Doneness Preferences

Objective: The objective of this study was to determine the impact of feeding consumers of varying degree of doneness preferences steaks cooked to multiple degrees of doneness on their perceptions of beef palatability. Study Description: Paired Low Choice frozen steaks from the posterior half of the strip loin were randomly assigned a degree of doneness of rare (140°F), medium-rare (145°F), medium (160°F), medium-well (165°F), or well-done (170°F). Consumer panelists, prescreened to participate in panels based on their degree of doneness preference, were served steak samples cooked to each of the five degrees of doneness under low-intensity red incandescent lighting to mask any degree of doneness differences among samples. Next, consumers were served steak samples under white incandescent lighting, with white fluorescent background lighting. Pre-screening consumers for degree of doneness preference allowed for a measure of the impact of “missing” the consumer’s ideal degree of doneness and quantification of the impact of both undercooking and overcooking steaks on consumer beef palatability ratings. The Bottom Line: When steaks are overcooked, palatability ratings decrease; however, undercooking has a positive effect on palatability perception regardless of the consumer’s degree of doneness preference

Consumer Juiciness Acceptability Supports the Beef Marbling Insurance Theory

Objective: The objective of this study was to determine whether increased marbling reduces the negative impact that increased degree of doneness has on consumer palatability scores. Study Description: Beef strip loins were collected to represent five quality treatments [Prime, Top choice, Low choice, Select, and Select enhanced; n = 12 pairs/quality grade] and fabricated to 1-in steaks. Steaks were cooked to one of six degrees of doneness: very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Consumers (n = 360) rated each steak for juiciness, tenderness, flavor, and overall liking on 100 The Bottom Line: Marbling could play a role in compensating for the negative effects of advanced degrees of doneness on juiciness acceptability, providing insight into the quality grade needed for consumers to be satisfied with juiciness based on their preferred degree of doneness

Consumer Evaluation of the Degree of Doneness of Beef Strip Loin Steaks Cooked to Six End-Point Temperatures

Objective: The objective of this study was to assess consumers’ degree of doneness practices in addition to their ability to identify beef steak degrees of doneness. Study Description: Beef strip loins (n = 24) from 12 animals representing five quality treatments [Prime, Top Choice, Low Choice, Select, and Select Enhanced (108%)] were collected. Steaks were cooked to an end-point temperature of very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Cooked steaks were cut in half, perpendicular to the long axis of the steak, and photographs were taken immediately on the internal face of the lateral side. A digital survey for consumers was developed for electronic evaluation of the cooked steak images. Consumers (n = 1,134) answered a demographics questionnaire, followed by questions pertaining to temperature and determining degree of doneness. Next, 10 steak images depicting varying degrees of doneness were randomly selected by Qualtrics Software for each consumer to identify the degree of doneness of the steak pictured. The Bottom Line: Consumers do not have a good understanding of beef degrees of doneness, and are unable to consistently and accurately identify degrees of doneness of steaks cooked to specified end-point temperatures. This can create challenges when consumers communicate their degree of doneness preferences at foodservice establishments

Chef Evaluation of the Degree of Doneness of Beef Strip Loin Steaks Cooked to Six End-Point Temperatures

Objective: The objective of this study was to assess foodservice steak preparation practices and chefs’ abilities to identify degrees of doneness of beef strip loin steaks. Study Description: Beef strip loins (n = 24) from 12 animals representing five quality treatments (Prime, Top Choice, Low Choice, Select, and Select Enhanced) were collected. Steaks were cooked to an end-point temperature of very-rare (130°F), rare (140°F), medium-rare (145°F), medium (160°F), well-done (170°F), or very well-done (180°F). Each cooked steak was cut in half, perpendicular to the long axis of the steak, and photographs were taken immediately of the internal face of the lateral side. A digital survey was developed for chefs for the electronic evaluation of the images of the cooked steaks. Chefs (n = 83) were recruited via email from around the U.S. using an established database of chefs from all segments of the industry. The Bottom Line: Chefs did not report they use the current published degree of doneness temperatures. Additionally, chefs commonly rated steaks one degree of doneness above the degree of doneness category commonly associated with the end-point temperature

Differential Dynamic Properties of Scleroderma Fibroblasts in Response to Perturbation of Environmental Stimuli

Diseases are believed to arise from dysregulation of biological systems (pathways) perturbed by environmental triggers. Biological systems as a whole are not just the sum of their components, rather ever-changing, complex and dynamic systems over time in response to internal and external perturbation. In the past, biologists have mainly focused on studying either functions of isolated genes or steady-states of small biological pathways. However, it is systems dynamics that play an essential role in giving rise to cellular function/dysfunction which cause diseases, such as growth, differentiation, division and apoptosis. Biological phenomena of the entire organism are not only determined by steady-state characteristics of the biological systems, but also by intrinsic dynamic properties of biological systems, including stability, transient-response, and controllability, which determine how the systems maintain their functions and performance under a broad range of random internal and external perturbations. As a proof of principle, we examine signal transduction pathways and genetic regulatory pathways as biological systems. We employ widely used state-space equations in systems science to model biological systems, and use expectation-maximization (EM) algorithms and Kalman filter to estimate the parameters in the models. We apply the developed state-space models to human fibroblasts obtained from the autoimmune fibrosing disease, scleroderma, and then perform dynamic analysis of partial TGF-β pathway in both normal and scleroderma fibroblasts stimulated by silica. We find that TGF-β pathway under perturbation of silica shows significant differences in dynamic properties between normal and scleroderma fibroblasts. Our findings may open a new avenue in exploring the functions of cells and mechanism operative in disease development

Petri Nets with Fuzzy Logic (PNFL): Reverse Engineering and Parametrization

Background: The recent DREAM4 blind assessment provided a particularly realistic and challenging setting for network reverse engineering methods. The in silico part of DREAM4 solicited the inference of cycle-rich gene regulatory networks from heterogeneous, noisy expression data including time courses as well as knockout, knockdown and multifactorial perturbations. Methodology and Principal Findings: We inferred and parametrized simulation models based on Petri Nets with Fuzzy Logic (PNFL). This completely automated approach correctly reconstructed networks with cycles as well as oscillating network motifs. PNFL was evaluated as the best performer on DREAM4 in silico networks of size 10 with an area under the precision-recall curve (AUPR) of 81%. Besides topology, we inferred a range of additional mechanistic details with good reliability, e.g. distinguishing activation from inhibition as well as dependent from independent regulation. Our models also performed well on new experimental conditions such as double knockout mutations that were not included in the provided datasets. Conclusions: The inference of biological networks substantially benefits from methods that are expressive enough to deal with diverse datasets in a unified way. At the same time, overly complex approaches could generate multiple different models that explain the data equally well. PNFL appears to strike the balance between expressive power and complexity. This also applies to the intuitive representation of PNFL models combining a straightforward graphical notation with colloquial fuzzy parameters