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The detection of meat quality defects can involve both subjective and objective methods. PSE-like meat is linked to a common pork defect and can be caused by rapid post-mortem damage of muscle fibers. This damage can again be linked to various factors, such as a low ultimate pH or a higher slaughter weight. PSE-like defects are characterized by discoloration, structural damage, and excessive moisture loss. However, the lack of suitable instrument-based methods makes the detection of PSE-like defects difficult, and subjective methods typically suffer from poorer reproducibility. The objective of this study was to establish how subjective visual evaluation correlates with electrical impedance spectroscopy and with traditional quality parameters. To do so, visual scoring was performed together with measurements of bioimpedance, color, and pH in two ham muscles (Adductor, Semimembranosus) for 136 animals 24-hours post-mortem. When comparing with visual scoring, Pearson correlation analysis shows the strongest correlation for bioimpedance (Py, r = −0.46, R2 = 21%), followed by pHu (r = 0.44, R2 = 19%). When using all five quality measures, i.e., Py, pHu, and CIELAB L* a* b*, the multivariate regression model had a prediction error of 0.76 for the visual scores. This was close to the error describing the subjective bias of visual scoring, more specifically the prediction error between the two observers (0.85). In all, Py showed the strongest correlation among instrument-based quality tests and alone may be used for predicting pork ham structural defects, i.e., as an instrument-based alternative for subjective, visual scoring. However, an instrument that combines Py with pH and/or L*a*b* would improve the prediction of PSE-like quality defects.

Correct food labeling is a legal requirement and helps consumers to make informed purchasing choices. Mislabeling defrosted meat as fresh is illegal in the EU. However, there are no standardized technologies to authenticate fresh versus defrosted meat. We address this by testing if bioimpedance-based measurements can separate defrosted meat from refrigerated-only meat at the end of shelf life, i.e., when also fresh meat shows deterioration. Pork sirloin samples from 20 pigs were first tested at 12 days postmortem (‘fresh group’). This time point was chosen to represent a typical use-by date for refrigerated storage of fresh pork. Then, all samples were transferred to a -24°C freezer for 3 days and thawed for 2 days before final testing (‘frozen-thawed group’).

Author(s): P. J. Fonseca [1]; D. Münch [2]; R. M. Hennig (corresponding author) [2] The vertebrate ear can analyse the frequency components of sound with high resolution, recognizing complex acoustic [...]

Physiological saline (0.9% NaCl) and deionized water were frozen in a laboratory chest freezer and impedance was monitored throughout freezing and thawing. The resistive and reactive components of electrical impedance were measured for these samples during freezing and thawing (heating) within a temperature range between 20 °C and −48 °C. The impedance of saline solution and de-ionized water increases sharply at the freezing point, similar to what is known for, e.g., complex tissues, including meat. Yet, only the saline solution impedance shows another sharp increment at a temperature between −30 and −20 °C. Changes of the electric properties after solidification suggest that the latter is linked to transformations of the ice lattice structure. We conclude that the electrical properties might serve as sensitive indicators of these phase changes.

Reports on a study of the frequency resolution of the Portuguese cicada Tettigetta josei. Categorical perception of sound in insects, which is a result of their ability to separate only broad-frequency bands; The capacity for fine-frequency resolution in the cicada; Possibility that the frequency-modulated songs of many cicada species may result from sensory drive.

Nucleotide-binding site leucine-rich repeat resistance genes (NLRs) allow plants to detect microbial effectors. We hypothesized that NLR expression patterns could reflect organ-specific differences in effector challenge and tested this by carrying out a meta-analysis of expression data for 1,235 NLRs from nine plant species. We found stable NLR root/shoot expression ratios within species, suggesting organ-specific hardwiring of NLR expression patterns in anticipation of distinct challenges. Most monocot and dicot plant species preferentially expressed NLRs in roots. In contrast, Brassicaceae species, including oilseed rape ( Brassica napus ) and the model plant Arabidopsis ( Arabidopsis thaliana ), were unique in showing NLR expression skewed toward the shoot across multiple phylogenetically distinct groups of NLRs. The Brassicaceae are also outliers in the sense that they have lost the common symbiosis signaling pathway, which enables intracellular infection by root symbionts. While it is unclear if these two events are related, the NLR expression shift identified here suggests that the Brassicaceae may have evolved unique pattern-recognition receptors and antimicrobial root metabolites to substitute for NLR protection. Such innovations in root protection could potentially be exploited in crop rotation schemes or for enhancing root defense systems of non-Brassicaceae crops., (© 2018 American Society of Plant Biologists. All Rights Reserved.)

Studies of protein N-glycosylation are important for answering fundamental questions on the diverse functions of glycoproteins in plant growth and development. Here we generated and characterised a comprehensive collection of Lotus japonicusLORE1 insertion mutants, each lacking the activity of one of the 12 enzymes required for normal N-glycan maturation in the glycosylation machinery. The inactivation of the individual genes resulted in altered N-glycan patterns as documented using mass spectrometry and glycan-recognising antibodies, indicating successful identification of null mutations in the target glyco-genes. For example, both mass spectrometry and immunoblotting experiments suggest that proteins derived from the α1,3-fucosyltransferase (Lj3fuct) mutant completely lacked α1,3-core fucosylation. Mass spectrometry also suggested that the Lotus japonicus convicilin 2 was one of the main glycoproteins undergoing differential expression/N-glycosylation in the mutants. Demonstrating the functional importance of glycosylation, reduced growth and seed production phenotypes were observed for the mutant plants lacking functional mannosidase I, N-acetylglucosaminyltransferase I, and α1,3-fucosyltransferase, even though the relative protein composition and abundance appeared unaffected. The strength of our N-glycosylation mutant platform is the broad spectrum of resulting glycoprotein profiles and altered physiological phenotypes that can be produced from single, double, triple and quadruple mutants. This platform will serve as a valuable tool for elucidating the functional role of protein N-glycosylation in plants. Furthermore, this technology can be used to generate stable plant mutant lines for biopharmaceutical production of glycoproteins displaying relative homogeneous and mammalian-like N-glycosylation features., (© 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.)

Membrane trafficking is required during plant immune responses, but its contribution to the hypersensitive response (HR), a form of programmed cell death (PCD) associated with effector-triggered immunity, is not well understood. HR is induced by nucleotide binding-leucine-rich repeat (NB-LRR) immune receptors and can involve vacuole-mediated processes, including autophagy. We previously isolated lazarus (laz) suppressors of autoimmunity-triggered PCD in the Arabidopsis thaliana mutant accelerated cell death11 (acd11) and demonstrated that the cell death phenotype is due to ectopic activation of the LAZ5 NB-LRR. We report here that laz4 is mutated in one of three VACUOLAR PROTEIN SORTING35 (VPS35) genes. We verify that LAZ4/VPS35B is part of the retromer complex, which functions in endosomal protein sorting and vacuolar trafficking. We show that VPS35B acts in an endosomal trafficking pathway and plays a role in LAZ5-dependent acd11 cell death. Furthermore, we find that VPS35 homologs contribute to certain forms of NB-LRR protein-mediated autoimmunity as well as pathogen-triggered HR. Finally, we demonstrate that retromer deficiency causes defects in late endocytic/lytic compartments and impairs autophagy-associated vacuolar processes. Our findings indicate important roles of retromer-mediated trafficking during the HR; these may include endosomal sorting of immune components and targeting of vacuolar cargo., (© 2015 American Society of Plant Biologists. All rights reserved.)

Autophagy is a homeostatic degradation and recycling process that is also involved in defense against microbial pathogens and in certain forms of cellular suicide. Autophagy has been proposed to negatively regulate plant immunity-associated cell death related to the hypersensitive response (HR), as older autophagy-deficient mutants are unable to contain this type of cell death 5 to 10 d after infection. Such spreading cell death was found to require NPR1 (nonexpressor of PR genes 1), but surprisingly did not occur in younger atg mutants. In contrast, we find that npr1 mutants are not impaired in rapid programmed cell death activation upon pathogen recognition. Furthermore, our molecular evidence suggests that the NPR1-dependent spreading cell death in older atg mutants may originate from an inability to cope with excessive accumulation of ubiquitinated proteins and ER stress which derive from salicylic acid (SA)-dependent signaling (e.g., systemic acquired resistance). We also demonstrate that both senescence and immunity-related cell death seen in older atg mutants can be recapitulated in younger atg mutants primed with ER stress. We therefore propose that the reduction in SA signaling caused by npr1 loss-of-function is sufficient to alleviate the stress levels accumulated during aging in autophagy deficient cells which would otherwise become insurmountable and lead to uncontrolled cell death.

The accelerated cell death 11 (acd11) mutant of Arabidopsis provides a genetic model for studying immune response activation and localized cellular suicide that halt pathogen spread during infection in plants. Here, we elucidate ACD11 structure and function and show that acd11 disruption dramatically alters the in vivo balance of sphingolipid mediators that regulate eukaryotic-programmed cell death. In acd11 mutants, normally low ceramide-1-phosphate (C1P) levels become elevated, but the relatively abundant cell death inducer phytoceramide rises acutely. ACD11 exhibits selective intermembrane transfer of C1P and phyto-C1P. Crystal structures establish C1P binding via a surface-localized, phosphate headgroup recognition center connected to an interior hydrophobic pocket that adaptively ensheaths lipid chains via a cleft-like gating mechanism. Point mutation mapping confirms functional involvement of binding site residues. A π helix (π bulge) near the lipid binding cleft distinguishes apo-ACD11 from other GLTP folds. The global two-layer, α-helically dominated, "sandwich" topology displaying C1P-selective binding identifies ACD11 as the plant prototype of a GLTP fold subfamily., (Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.)

The United States Environmental Protection Agency (EPA) collected drinking water occurrence data for perchlorate in the Unregulated Contaminant Monitoring Regulation (UCMR 1; 2001-2005) using EPA Method 314.0. To address the interest in increasing sensitivity and selectivity for the analysis of perchlorate, three new methods, EPA Methods 314.1, 331.0 and 332.0, were subsequently published by EPA for the analysis of perchlorate in drinking water. In 2006, an automated two-dimensional ion chromatography (2D-IC) method for measuring perchlorate with suppressed conductivity detection was developed. Two-dimensional IC is essentially an automated "heart-cutting", column concentration and matrix elimination technique. In the first dimension, a large sample volume is injected onto a first separation column and the separated matrix ions are diverted to waste while the analyte(s) of interest are selectively cut, trapped and concentrated in a concentrator column. In the second dimension, the contents from the concentrator column are eluted onto a second analytical column for separation and quantitation of the analyte(s) of interest. Incorporation of two columns with different affinities for the analyte(s) in a single analysis can provide comparable selectivity and superior sensitivity to a method using second column confirmation in a second separate analysis step. Use of this approach led to the development of a new, highly sensitive and selective 2D-IC, suppressed conductivity method with a Lowest Concentration Minimum Reporting Level (LCMRL) of 55 ng/L for perchlorate in drinking water samples. This new method has comparable sensitivity and selectivity and is simpler and more economical than IC-mass spectrometric (MS) or IC-MS-MS techniques. The method is now being prepared for publication as EPA Method 314.2.

Since 1997 there has been increasing interest in the development of analytical methods for the analysis of perchlorate. The US Environmental Protection Agency (EPA) Method 314.0, which was used during the first Unregulated Contaminant Monitoring Regulation (UCMR) cycle, supports a method reporting limit (MRL) of 4.0 microg/L. The non-selective nature of conductivity detection, combined with very high ionic strength matrices, can create conditions that make the determination of perchlorate difficult. The objective of this work was to develop an automated, suppressed conductivity method with improved sensitivity for use in the second UCMR cycle. The new method, EPA Method 314.1, uses a 35 mm x 4 mm cryptand concentrator column in the sample loop position to concentrate perchlorate from a 2 mL sample volume, which is subsequently rinsed with 10 mM NaOH to remove interfering anions. The cryptand concentrator column is combined with a primary AS16 analytical column and a confirmation AS20 analytical column. Unique characteristics of the cryptand column allow perchlorate to be desorbed from the cryptand trap and refocused on the head of the guard column for subsequent separation and analysis. EPA Method 314.1 has a perchlorate lowest concentration minimum reporting level (LCMRL) of 0.13 microg/L in both drinking water and laboratory synthetic sample matrices (LSSM) containing up to 1,000 microg/L each of chloride, bicarbonate and sulfate.

US Environmental Protection Agency (EPA) Method 331 determines perchlorate in drinking water using non-suppressed ion chromatography with tandem mass spectrometry. This study reports the results of calibration and recovery studies in reagent water, as well as of a recovery study in simulated drinking water (i.e., total dissolved solids are 500 mg/mL each of chloride, sulfate, and bicarbonate). The perchlorate concentrations in the study ranged from 0.05 to 64 ng/mL. At 95% confidence, the Hubaux-Vos detection limit (H-V DL) was 0.04 ng/mL for the calibration study and the simulated-drinking-water recovery study, and 0.03 ng/mL for the reagent-water recovery study. The lowest concentration minimum reporting level was 0.03 ng/mL for reagent water and 0.0 7 ng/mL for simulated drinking water, again at 95% confidence.

Studies were performed to investigate the roles of methanol and acetonitrile on the retention mechanism of an active pharmaceutical ingredient (API) and related compounds with a reversed phase phenyl column. Different retention orders were observed depending upon whether acetonitrile or methanol was used as the organic modifier. We propose that acetonitrile impedes the selective pi-pi interactions between the analyte molecules and the phenyl groups in the stationary phase. Further study with 1-naphthoic acid and 1-naphthol as test compounds in the HPLC separation provides additional support for the influence of acetonitrile on pi-pi interactions between analyte molecules and a phenyl stationary phase. This study suggests that methanol be used as the preferred organic modifier with phenyl columns to achieve selectivity based upon pi-pi interactions.

Currently, the most promising analytical methodology for low-level determination and confirmation of perchlorate (ClO4-) in drinking water is ion chromatography followed by electrospray ionization mass spectrometric detection (IC-ESI-MS). However, there are still potentially limiting situations that must be considered when analyzing real world samples by IC-ESI-MS. They are: (1) co-elution of contaminants with fragment ions having the same m/z as ClO4-, (2) high background counts at the m/z of interest leading to a subsequent decrease in signal-to-noise, (3) gradual loss of sensitivity occurring over time as the sampling cone and/or ion optics of the mass spectrometer are fouled, and (4) suppression of gas phase ion formation (ionization suppression) that can occur if high concentrations of contaminants co-elute with ClO4-. An internal standard whose response, on the column and in the electrospray, is similar to that of ClO4- would give the highest degree of accuracy possible in situations 3 and 4 listed above. Commercially available NaClO4 that was enriched with oxygen-18 was evaluated for its potential as an internal standard. The level of oxygen-18 (18O) enrichment was verified, the stability of the enriched ClO4- in aqueous solutions was determined, and method performance parameters such as method detection limits, accuracy, precision and ruggedness using the enriched ClO4 as an internal standard were determined. Internal and external calibration yielded similar results with respect to calibration, detection limits, and short-term precision. However, the enriched isotopic internal standard showed superior results with respect to ruggedness and percent recovery of spikes in ground water and synthetic water samples.

Preservation of chemical analytes in drinking water samples is necessary to obtain accurate information concerning contaminant occurrence. Sample preservation to prevent biodegradation is important for most samples and analytes. With the unique demands of environmental methods, it is not always possible to kill all microorganisms without having undesirable effects. To find a suitable preservative, the sample, analysis, and preservation needs should be considered. During method development of U.S. Environmental Protection Agency (EPA) Methods 526 (for unstable semivolatile compounds) and 532 (for phenylurea pesticides), a number of studies were conducted to identify compatible microbial inhibitors. Copper sulfate was successfully used in Method 532 and is an excellent first-choice antimicrobial agent for many applications. Copper sulfate can catalyze hydrolysis reactions for some pesticides such as those analyzed in Method 526. Under these conditions, a nonmetal compound of antimicrobial activity must be considered. During the development of Method 526, a survey of alternate organic based antimicrobial compounds found that diazolidinyl urea worked well in the method. Several other candidate microbial inhibitors were identified that could have application to other environmental methods. A general approach to selecting antimicrobial compounds in future environmental methods in water matrixes is discussed.

U.S. Environmental Protection Agency (EPA) Method 526 was developed for the analysis of target analytes that are subject to degradation by hydrolysis. Two technical hurdles that had to be overcome were preservation of the target analytes and selection of a suitable solid-phase extraction material. The target analytes were diazinon, disulfoton, fonofos, terbufos, prometon, 1,2-diphenylhydrazine, nitrobenzene, acetochlor, 2,4,6-trichlorophenol, 2,4-dichlorophenol, and cyanazine. Diazolidinyl urea was used for the first time as a microbial inhibitor in an EPA drinking water method. Experiment confirmed antimicrobial agents containing copper or mercury salts increased hydrolysis degradation rates. Trisodium ethylenediaminetetraacetic acid salt was added to chelate metal ions that may increase hydrolysis rates. A pH 7 buffer of tris(hydroxymethyl)aminomethane (Tris) and Tris hydrochloride was used to minimize rates of hydrolysis. The use of ascorbic acid prevented degradation of 2,4-dichlorophenol, terbufos, fonofos, diazinon, and disulfoton due to residual chlorine. Samples were extracted using a styrene divinylbenzene solid-phase material and analyzed by capillary column gas chromatography/mass spectrometry. A 21-day storage stability study, together with precision and accuracy studies, showed that this method has suitable sensitivity, accuracy, precision, and ruggedness for use in the EPA's Unregulated Contaminant Monitoring Rule drinking water occurrence survey.

In July 1997, the US Environmental Protection Agency (EPA) began sampling and analyzing drinking water matrices from US municipalities serving populations greater than 100,000 for low-level bromate (> 0.20 microgram/l) in support of the Information Collection Rule (ICR) using the selective anion concentration (SAC) method. In September 1997, EPA published Method 300.1 which lowered the Method 300.0 bromate method detection limit (MDL) from 20.0 to 1.4 micrograms/l. This paper describes the research conducted at the EPA's Technical Support Center laboratory investigating a single post-column reagent, o-dianisidine (ODA), which has been successfully coupled to EPA Method 300.1 to extend the MDL for bromate. Initial studies indicate that this method offers a MDL which approaches the EPA's SAC method with the added benefit of increased specificity, shortened analysis time and reduced sample preparation. The method provides excellent ruggedness and acceptable precision and accuracy with a bromate MDL in reagent water of 0.1 microgram/l, and a method reporting limit of 0.50 microgram/l.

Following a case of mannitol-induced respiratory and circulatory collapse, the effects of hyperosmolar injections on pulmonary arterial pressure, systemic blood pressure, and cardiac output were studied in dogs. The injection of 20 ml of 10% NaCl into the pulmonary artery increased pulmonary arterial pressure and decreased systemic blood pressure by approximately 50% of control values. Injections of solutions of equal hyperosmolar strength, 50 ml of 25% mannitol or 50 ml of 4% NaCl into the pulmonary artery produced no significant elevation of pulmonary arterial pressure, but were associated with comparable decreases in systemic blood pressure. When allowed to vary, cardiac output increased with injections of all three hyperosmolar solutions, yet was still accompanied by falls in systemic blood pressure as large as when cardiac output was held constant. Vagotomy did not prevent these changes in systemic and pulmonary arterial pressure, nor the increase in cardiac output. After five to 10 injections, the decreases in system blood pressure with any of the solutions and the increases in pulmonary arterial pressure with 10% NaCl disappeared and further injections were without effect. It is concluded that adminstration of mannitol probably does not cause pulmonary edema due to fluid overload, nor does it cause heart failure as evidenced by increases in pulmonary arterial pressure. However, rapid injection may cause a fall in blood pressure and may on occasion be accompanied by bronchospasm, especially in sensitive subjects.