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

Métodos para a climatização de bananas ‘prata-anã’ produzidas na Amazônia Setentrional brasileira.

O objetivo, neste trabalho, foi avaliar o uso da climatização para a uniformização de bananas 'Prata-Anã' produzidas em Boa Vista-RR. Após colhidos, os frutos foram selecionados no formato de buquês, sanitizados, climatizados por abafamento com lona plástica ou por imersão em solução de Ethrel®, embalados com filme de polietileno de baixa densidade e armazenados por quatro períodos de tempo (0; 10;20 e 30 dias) a 12 ± 1 ºC e 93 ± 2% de UR. Após cada período de armazenamento refrigerado (AR) os frutos foram submetidos ao armazenamento em condições ambiente (22 ± 1 ºC e 75 ± 3% UR), retirados das embalagens plásticas e sendo analisados após 1; 2; 3 e 4 dias. As seguintes análises foram realizadas: perda de massa fresca, coloração da casca, produção de etileno e CO2, atividade das enzimas pectinametilesterase e poligalacturonase, acidez titulável (AT), pectina total e solúvel, amido e sólidos solúveis (SS). Não houve diferenças significativas entre os métodos de climatização, porém verificou-se que, quanto maior o período de AR e de condicionamento, menor foi o período de conservação das bananas 'Prata-Anã'. Ficou evidenciado, também, que a climatização, independentemente do método utilizado, deve ser realizada em até 20 dias após a colheita, nas condições de AR aqui testadas. Nessas condições, foi possível manter a qualidade sensorial das bananas por até 3 dias após a retirada dos frutos do armazenamento refrigerado

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

Nonparametric Bayesian inference for perturbed and orthologous gene regulatory networks

Motivation: The generation of time series transcriptomic datasets collected under multiple experimental conditions has proven to be a powerful approach for disentangling complex biological processes, allowing for the reverse engineering of gene regulatory networks (GRNs). Most methods for reverse engineering GRNs from multiple datasets assume that each of the time series were generated from networks with identical topology. In this study, we outline a hierarchical, non-parametric Bayesian approach for reverse engineering GRNs using multiple time series that can be applied in a number of novel situations including: (i) where different, but overlapping sets of transcription factors are expected to bind in the different experimental conditions; that is, where switching events could potentially arise under the different treatments and (ii) for inference in evolutionary related species in which orthologous GRNs exist. More generally, the method can be used to identify context-specific regulation by leveraging time series gene expression data alongside methods that can identify putative lists of transcription factors or transcription factor targets. Results: The hierarchical inference outperforms related (but non-hierarchical) approaches when the networks used to generate the data were identical, and performs comparably even when the networks used to generate data were independent. The method was subsequently used alongside yeast one hybrid and microarray time series data to infer potential transcriptional switches in Arabidopsis thaliana response to stress. The results confirm previous biological studies and allow for additional insights into gene regulation under various abiotic stresses. Availability: The methods outlined in this article have been implemented in Matlab and are available on request

Relationship of Myofibrillar Fragmentation Index to Warner-Bratzler Shear Force and Palatability Tenderness of Longissimus Lumborum and Semitendinosus Steaks

Objective: The objective of this study was to determine the relationship between the myofibrillar fragmentation index, Warner-Bratzler shear force and sensory traits of longissimus lumborum (strip loin), and the semitendinosus (eye of round) steaks. Study Description: Forty beef strip loins and 40 eye of rounds were collected, divided into anatomical location, and cut into steaks. Steaks used for Warner-Bratzler shear force and sensory panel review were cooked to 160°F. For Warner-Bratzler, six 1-in cores were sheared with a Warner-Bratzler shear head. Sensory steaks were served to panelists trained according to American Meat Science Association guidelines for sensory evaluation. Procedures described by Culler et al. (1978) were used to determine myofibrillar fragmentation index. The Bottom Line: The correlation between myofibrillar fragmentation index, Warner-Bratzler shear force, and sensory measures of tenderness were weak, indicat­ing myofibrillar fragmentation index was not a reliable indicator of beef tenderness for the muscles evaluated

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

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