AC Domain Research Articles

Soft fault diagnosis in linear circuits: Test selection and non-iterative identification procedure

The paper deals with the diagnosis of soft faults in linear electronic circuits. Circuits containing operational amplifiers operating at low frequencies are considered. A method for identifying single and double faults in the AC domain is proposed. The method is non-iterative and relies on certain relations derived from the modified nodal description of the circuit. An essential part of the paper is a procedure enabling the selection of measurement nodes and test frequencies. The algorithm considers the AC sensitivities, the measurement accuracy, and the diagnostic method applied. The effectiveness of both methods was verified on several electronic circuits. The simulation and laboratory tests were done. Considering parameter tolerances and measurement uncertainties leads to determining intervals of parameter values covering the actual faults.

The role of electron transfer in the enzymatic activity of a photoactivable adenylate cyclase.

OaPAC is a photoactivated adenylate cyclase (PAC) from the photosynthetic cyanobacterium Oscillatoria acuminata and belongs to a class of photoactive flavoenzymes which are involved in the conversion of ATP (adenosine triphosphate) to the important second messenger cAMP (cyclic adenosine monophosphate). The photoactivation is controlled by a BLUF (Blue Light Sensing Using Flavin) domain; a well-known light-triggered switch present in many biological photoreceptors and able to control photochemical energy into a diverse set of cellular responses (e.g. phototaxis, photophobia, enzyme activity, gene expression). Blue-light excitation of the BLUF domain of OaPAC results in a proton-coupled electron transfer process where the primary electron and proton donor is a tyrosine residue in the vicinity of the flavin. The electron transfer to the flavin is accompanied by a reorganization of its hydrogen bond network, and the induced structural changes are believed to propagate towards the AC domain enabling the conversion of ATP to cAMP. In this work we studied the relation between the electron transfer and the activity of the enzyme using ultrafast and fluorescence spectroscopy as well as differential scanning calorimetry. A.L. acknowledges funding from the Hungarian National Research and Innovation Office (K-137557).

Four Cholesterol-Recognition Motifs in the Pore-Forming and Translocation Domains of Adenylate Cyclase Toxin Are Essential for Invasion of Eukaryotic Cells and Lysis of Erythrocytes.

Adenylate Cyclase Toxin (ACT or CyaA) is one of the important virulence factors secreted by Bordetella pertussis, the bacterium causative of whooping cough. ACT debilitates host defenses by production of unregulated levels of cAMP into the cell cytosol upon delivery of its N-terminal domain with adenylate cyclase activity (AC domain) and by forming pores in the plasma membrane of macrophages. Binding of soluble toxin monomers to the plasma membrane of target cells and conversion into membrane-integrated proteins are the first and last step for these toxin activities; however, the molecular determinants in the protein or the target membrane that govern this conversion to an active toxin form are fully unknown. It was previously reported that cytotoxic and cytolytic activities of ACT depend on membrane cholesterol. Here we show that ACT specifically interacts with membrane cholesterol, and find in two membrane-interacting ACT domains, four cholesterol-binding motifs that are essential for AC domain translocation and lytic activities. We hypothesize that direct ACT interaction with membrane cholesterol through those four cholesterol-binding motifs drives insertion and stabilizes the transmembrane topology of several helical elements that ultimately build the ACT structure for AC delivery and pore-formation, thereby explaining the cholesterol-dependence of the ACT activities. The requirement for lipid-mediated stabilization of transmembrane helices appears to be a unifying mechanism to modulate toxicity in pore-forming toxins.

Resonant controller of single‐stage off‐board EV charger in G2V and V2G modes

This study presents the control design and implementation of a three-phase single-stage off-board electric vehicle (EV) charger. The charger is controlled to perform four quadrants operation in active–reactive (P–Q) power plane. Generally, the control of the EV charger consists of two control loops, i.e. exterior (slow) loop and fast-acting interior loop. Since the signals to be regulated in outer loop are DC in nature, they can be easily handled by regular proportional plus integral regulators. The inner loop control may also be performed in the DC domain, but inaccuracy involved in determining the parameter-dependent decoupling terms and difficulty in setting the gain for fast-acting inner loops make it unfavourable. Therefore, the inner control is performed in AC domain, where the signals are periodic. The proportional plus resonant controller is found to be very useful in tracking such type of periodic signals of fixed frequency, and accordingly, it has been designed and successfully implemented for the proposed work. The proposed methodology has been tested for eight different modes in the P–Q-plane. The system is simulated in MATLAB/Simulink environment and implemented in real time with a scaled-down hardware prototype.

NiTi memristive behavior

In this paper, the experimental study and confirmation of the memristive behavior demonstrated by nanowires made of a smart alloy, namely NiTi, are presented. Further contribution to the characterization of the proposed novel NiTi memristor, included measurements in the ac domain, confirming the memristive nature of these NiTi wires/devices. These measurements included the device's response to triangular current excitation, as well as to pulse driving. In all cases, a study of the noise registered has taken place. According to the theory, since NiTi's memristive behavior is depended on its temperature, it is classified as an extended memristor.

A SystemC-AMS Framework for the Design and Simulation of Energy Management in Electric Vehicles

Driving range is one of the most critical issues for electric vehicles (EVs): running out of battery charge while driving results in serious inconvenience even comparable to a vehicle breakdown, as an effect of long fuel recharging times and lack of charging facilities. This may discourage EVs for current and potential customers. As an effect, the dimensioning of the energy subsystem of an EV is a crucial issue: the choice of the energy storage components and the policies for their management should be validated at design time through simulations, so to estimate the vehicle driving range under reference driving profiles. Thus, it is necessary to build a simulation framework that considers an EV power consumption model that accounts for the characteristics of the vehicle and the driving route, plus accurate models for all power components, including batteries and renewable power sources. The goal of this paper is to achieve such an early EV simulation, through the definition of a SystemC-AMS framework, which models simultaneously the physical and mechanical evolution, together with energy flows and environmental characteristics. The proposed solution extends the state-of-the-art framework for the simulation of electrical energy systems with support for mechanical descriptions and the AC domain, by finding a good balance between accuracy and simulation speed and by formalizing the new information and energy flows. The experimental results demonstrate that the performance of the proposed approach in terms of accuracy and simulation speed w.r.t. the current state-of-the-art and its effectiveness at supporting EV design with an enhanced exploration of the alternatives.

Characterization of the Intrinsic Phospholipase A1 Activity of Bordetella pertussis Adenylate Cyclase Toxin.

Adenylate cyclase toxin (ACT, CyaA) is one of the important virulence factors secreted by the whooping cough bacterium Bordetella pertussis, and it is essential for the colonization of the human respiratory tract by this bacterium. Cytotoxicity by ACT results from the synergy between toxin’s two main activities, production of supraphysiological cAMP levels by its N-terminal adenylate cyclase domain (AC domain), and cell membrane permeabilization, induced by its C-terminal pore-forming domain (hemolysin domain), which debilitate the host defenses. In a previous study we discovered that purified ACT is endowed with intrinsic phospholipase A1 (PLA) activity and that Ser in position 606 of the ACT polypeptide is a catalytic site for such hydrolytic activity, as part of G-X-S-X-G catalytic motif. Recently these findings and our conclusions have been directly questioned by other authors who claim that ACT-PLA activity does not exist. Here we provide new data on ACT phospholipase A1 characteristics. Based on our results we reaffirm our previous conclusions that ACT is endowed with PLA activity; that our purified ACT preparations are devoid of any impurity with phospholipase A activity; that ACT-S606A is a PLA-inactive mutant and thus, that Ser606 is a catalytic site for the toxin hydrolytic activity on phospholipids, and that ACT-PLA activity is involved in AC translocation.

Adolescent and Young Adult (AYA) Hematopoietic Cell Transplantation (HCT) Recipients Have Similar Quality of Life (QoL) Compared to Older Adults in the First Year Post-Transplantation

▪Background: HCT is physically and psychologically challenging and patients are prone to QoL impairments. AYAs are a unique population that faces hurdles due to dynamic changes in several aspects of their life, and may be particularly prone to QoL issues during HCT. The aim of this study was to determine if QoL differences exist between AYA and older adult HCT recipients pre- and post-HCT. Additionally, we aimed to determine if there has been a change in QoL for AYA transplant recipients in recent years, as more focus has been placed on supporting this unique population.Methods: QoL data were collected prospectively pre-HCT (baseline [BL]) and in follow-up post-transplant on patients undergoing HCT from Jun 2003 through Dec 2017 at Cleveland Clinic. Autologous HCT recipients are followed routinely through day +42 post-transplant, while allogeneic recipients are followed through at least one year or more. QoL was self-reported by patients using the Functional Assessment of Cancer Therapy-Bone Marrow Transplantation (FACT-BMT) questionnaire. FACT-BMT consists of five domain scores (Physical Wellbeing [PWB], Social Wellbeing [SWB], Emotional Wellbeing [EWB], Functional Wellbeing [FWB], and Additional Concerns [AC]) and two summary scores (trial outcome index [TOI, PWB+FWB+AC], and Total FACT Score. Scores were compared for younger AYA (age 15-29 years), older AYA (age 30-39 years) and older adults (age 40-60 years). We excluded patients >60 years from analysis as this group may have their own unique challenges. Repeated measures analysis of variance was used to assess differences among age groups and among time points. Pearson correlation (r) was used to determine if BL QOL had improved from 2003-2017 in AYA cohort. Separate analyses were performed for autologous and allogeneic cohorts.Results: Autologous HCT cohort included 128 AYA patients (56 younger AYA) and 355 older adults, and allogeneic HCT cohort included 136 AYA patients (76 younger AYA) and 295 older adults Autologous patients in all three groups were similar for baseline characteristics except for diagnosis (table 1). Among allogeneic patients similar rates of graft-versus host disease were seen for all three groups, and baseline characteristics were similar except for ECOG performance status (table 1). Among autologous recipients, no single QoL domain or composite score differed among the three age groups at baseline or at day +42 post-HCT (Figure 1a). In all age groups, QoL improved from baseline to D+42 in autologous HCT recipients (mean Total Score 149 vs. 152, p=0.001). Similarly, among the allogeneic HCT recipients, no single QoL domain or composite score differed among the three age groups at baseline, day +100, +180, or +365 post-HCT (Figure 1b). Among all patients compared to BL (mean 146), total FACT score improved at day +180 (150, p=0.022) and +365 (152, p=0.005), but not at day 100 (145, p=0.57). Among autologous recipients, none of the BL FACT domains improved over time since 2003. In contrast, AYA allogeneic recipients also had no significant change in BL scores since 2003 for PWB, SWB, EWB, FWB, however there was improvement in AC (r=0.26, p=0.003, TOI (r=0.23, p=0.008), and total FACT score (r=0.19, p=0.03).Conclusions: AYA HCT recipients do not have inferior QoL compared to older adults in the first 42 days after autologous HCT and the first year after allogeneic HCT. Interestingly, QoL improvements in AYA patients have occurred in recent years for allogeneic but not autologous patients. Improvements in QoL of allogeneic patients is driven by the AC domain, which addresses multiple psychosocial aspects which have been emphasized in recent years. Continued efforts to tailor treatment and support for AYA HSCT recipients is critical to improving outcomes. DisclosuresAdvani:Glycomimetics: Consultancy; Novartis: Consultancy; Amgen: Research Funding; Pfizer: Honoraria, Research Funding. Majhail:Atara: Honoraria; Anthem, Inc.: Consultancy; Incyte: Honoraria.

Rhodopsin-cyclases for photocontrol of cGMP/cAMP and 2.3\u2009\xc5 structure of the adenylyl cyclase domain

The cyclic nucleotides cAMP and cGMP are important second messengers that orchestrate fundamental cellular responses. Here, we present the characterization of the rhodopsin-guanylyl cyclase from Catenaria anguillulae (CaRhGC), which produces cGMP in response to green light with a light to dark activity ratio >1000. After light excitation the putative signaling state forms with τ = 31 ms and decays with τ = 570 ms. Mutations (up to 6) within the nucleotide binding site generate rhodopsin-adenylyl cyclases (CaRhACs) of which the double mutated YFP-CaRhAC (E497K/C566D) is the most suitable for rapid cAMP production in neurons. Furthermore, the crystal structure of the ligand-bound AC domain (2.25 Å) reveals detailed information about the nucleotide binding mode within this recently discovered class of enzyme rhodopsin. Both YFP-CaRhGC and YFP-CaRhAC are favorable optogenetic tools for non-invasive, cell-selective, and spatio-temporally precise modulation of cAMP/cGMP with light.

Relationship between QTL for grain shape, grain weight, test weight, milling yield, and plant height in the spring wheat cross RL4452/'AC Domain'.

Kernel morphology characteristics of wheat are complex and quantitatively inherited. A doubled haploid (DH) population of the cross RL4452/‘AC Domain’ was used to study the genetic basis of seed shape. Quantitative trait loci (QTL) analyses were conducted on a total of 18 traits: 14 grain shape traits, flour yield (Fyd), and three agronomic traits (Plant height [Plht], 1000 Grain weight [Gwt], Test weight [Twt]), using data from trial locations at Glenlea, Brandon, and Morden in Manitoba, Canada, between 1999 and 2004. Kernel shape was studied through digital image analysis with an Acurum® grain analyzer. Plht, Gwt, Twt, Fyd, and grain shape QTL were correlated with each other and QTL analysis revealed that QTL for these traits often mapped to the same genetic locations. The most significant QTL for the grain shape traits were located on chromosomes 4B and 4D, each accounting for up to 24.4% and 53.3% of the total phenotypic variation, respectively. In addition, the most significant QTL for Plht, Gwt, and Twt were all detected on chromosome 4D at the Rht-D1 locus. Rht-D1b decreased Plht, Gwt, Twt, and kernel width relative to the Rht-D1a allele. A narrow genetic interval on chromosome 4B contained significant QTL for grain shape, Gwt, and Plht. The ‘AC Domain’ allele reduced Plht, Gwt, kernel length and width traits, but had no detectable effect on Twt. The data indicated that this variation was inconsistent with segregation at Rht-B1. Numerous QTL were identified that control these traits in this population.

Phospholipase A activity of adenylate cyclase toxin mediates translocation of its adenylate cyclase domain

Adenylate cyclase toxin (ACT or CyaA) plays a crucial role in respiratory tract colonization and virulence of the whooping cough causative bacterium Bordetella pertussis Secreted as soluble protein, it targets myeloid cells expressing the CD11b/CD18 integrin and on delivery of its N-terminal adenylate cyclase catalytic domain (AC domain) into the cytosol, generates uncontrolled toxic levels of cAMP that ablates bactericidal capacities of phagocytes. Our study deciphers the fundamentals of the heretofore poorly understood molecular mechanism by which the ACT enzyme domain directly crosses the host cell membrane. By combining molecular biology, biochemistry, and biophysics techniques, we discover that ACT has intrinsic phospholipase A (PLA) activity, and that such activity determines AC translocation. Moreover, we show that elimination of the ACT-PLA activity abrogates ACT toxicity in macrophages, particularly at toxin concentrations close to biological reality of bacterial infection. Our data support a molecular mechanism in which in situ generation of nonlamellar lysophospholipids by ACT-PLA activity into the cell membrane would form, likely in combination with membrane-interacting ACT segments, a proteolipidic toroidal pore through which AC domain transfer could directly take place. Regulation of ACT-PLA activity thus emerges as novel target for therapeutic control of the disease.

A Novel Method Towards Time-Efficient Fault Analysis of Analog and Mixed-Signal Circuits

A novel method of nodal impedance calculation is presented in this paper. This method is capable of time-efficient calculation of arbitrary two-point complex impedance in an analog and mixed-signal circuit and could improve the development time of impedance-based tests both in DC and AC domain. A fault simulation methodology based on the proposed method is described in detail. Several experiments are provided that prove the time efficiency of the method. Experimental application showing the benefits of the method on a real circuit is provided as well.

Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro.

Bordetella pertussis, the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous haemagglutinin (FHA), a surface-displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al. to propose the ACT-FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro. Exogenous ACT inhibits biofilm formation in a concentration-dependent manner and the N-terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C-terminal segment of FHA with ∼650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C-terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host-directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT.

Negatively charged residues of the segment linking the enzyme and cytolysin moieties restrict the membrane-permeabilizing capacity of adenylate cyclase toxin

The whooping cough agent, Bordetella pertussis, secretes an adenylate cyclase toxin-hemolysin (CyaA) that plays a crucial role in host respiratory tract colonization. CyaA targets CR3-expressing cells and disrupts their bactericidal functions by delivering into their cytosol an adenylate cyclase enzyme that converts intracellular ATP to cAMP. In parallel, the hydrophobic domain of CyaA forms cation-selective pores that permeabilize cell membrane. The invasive AC and pore-forming domains of CyaA are linked by a segment that is unique in the RTX cytolysin family. We used mass spectrometry and circular dichroism to show that the linker segment forms α-helical structures that penetrate into lipid bilayer. Replacement of the positively charged arginine residues, proposed to be involved in target membrane destabilization by the linker segment, reduced the capacity of the toxin to translocate the AC domain across cell membrane. Substitutions of negatively charged residues then revealed that two clusters of negative charges within the linker segment control the size and the propensity of CyaA pore formation, thereby restricting the cell-permeabilizing capacity of CyaA. The ‘AC to Hly-linking segment’ thus appears to account for the smaller size and modest cell-permeabilizing capacity of CyaA pores, as compared to typical RTX hemolysins.

Identification of candidate genes, regions and markers for pre-harvest sprouting resistance in wheat (Triticum aestivum L.).

BackgroundPre-harvest sprouting (PHS) of wheat grain leads to a reduction in grain yield and quality. The availability of markers for marker-assisted selection (MAS) of PHS resistance will serve to enhance breeding selection and advancement of lines for cultivar development. The aim of this study was to identify candidate regions and develop molecular markers for PHS resistance in wheat. This was achieved via high density mapping of single nucleotide polymorphism (SNP) markers from an Illumina 90 K Infinium Custom Beadchip in a doubled haploid (DH) population derived from a RL4452/‘AC Domain’ cross and subsequent detection of quantitative trait loci (QTL) for PHS related traits (falling number [FN], germination index [GI] and sprouting index [SI]). SNP marker sequences flanking QTL were used to locate colinear regions in Brachypodium and rice, and identify genic markers associated with PHS resistance that can be utilized for MAS in wheat.ResultsA linkage map spanning 2569.4 cM was constructed with a total of 12,201 SNP, simple sequence repeat (SSR), diversity arrays technology (DArT) and expressed sequence tag (EST) markers. QTL analyses using Multiple Interval Mapping (MIM) identified four QTL for PHS resistance traits on chromosomes 3B, 4A, 7B and 7D. Sequences of SNPs flanking these QTL were subject to a BLASTN search on the International Wheat Genome Sequencing Consortium (IWGSC) database (http://wheat-urgi.versailles.inra.fr/Seq-Repository). Best survey sequence hits were subject to a BLASTN search on Gramene (www.gramene.org) against both Brachypodium and rice databases, and candidate genes and regions for PHS resistance were identified. A total of 18 SNP flanking sequences on chromosomes 3B, 4A, 7B and 7D were converted to KASP markers and validated with matching genotype calls of Infinium SNP data.ConclusionsOur study identified candidate genes involved in abscissic acid (ABA) and gibberellin (GA) metabolism, and flowering time in four genomic regions of Brachypodium and rice respectively, in addition to 18 KASP markers for PHS resistance in wheat. These markers can be deployed in future genetic studies of PHS resistance and might also be useful in the evaluation of PHS in germplasm and breeding material.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-014-0340-1) contains supplementary material, which is available to authorized users.

Comparative yield, disease resistance and response to fungicide for forty-five historic Canadian wheat cultivars

Martens, G., Lamari, L., Grieger, A., Gulden, R. H. and McCallum, B. 2014. Comparative yield, disease resistance and response to fungicide for forty-five historic Canadian wheat cultivars. Can. J. Plant Sci. 94: 371–381. Forty-five historic Canadian spring wheat cultivars, ranging from Red Fife (1870) to modern cultivars, were compared for yield and disease resistance in field trials from 2007 to 2010. A split-plot design was used to test yield, leaf rust and Fusarium head blight resistance, with or without a fungicide application. Older cultivars were generally lower yielding and more leaf rust susceptible than modern cultivars; this difference was greatest in 2007 and 2010 under heavier leaf rust. Response to fungicide application was highest in 2007 and 2010. In 2008, leaf rust was very low, and fungicide application had a slightly negative effect on yield overall. Cultivars that have good leaf rust resistance, such as Pasqua, AC Minto, and 5600 HR, had a negligible response to fungicide, whereas older, susceptible cultivars had a larger response. Fusarium head blight levels were too low to compare the cultivars. The highest-yielding cultivars in the untreated plots were AC Domain, 5500HR, AC Cora, Roblin and Barrie, whereas AC Cora, AC Domain, McKenzie, Roblin and AC Intrepid were the highest yielding in the fungicide-treated plots. AC Domain, AC Barrie and Roblin were among the most popular wheat cultivars in Manitoba, in terms of seeded area from the early 1990s to 2009.

Identification of photoactivated adenylyl cyclases in Naegleria australiensis and BLUF-containing protein in Naegleria fowleri

Complete genome sequencing of Naegleria gruberi has revealed that the organism encodes polypeptides similar to photoactivated adenylyl cyclases (PACs). Screening in the N. australiensis genome showed that the organism also encodes polypeptides similar to PACs. Each of the Naegleria proteins consists of a "sensors of blue-light using FAD" domain (BLUF domain) and an adenylyl cyclase domain (AC domain). PAC activity of the Naegleria proteins was assayed by comparing sensitivities of Escherichia coli cells heterologously expressing the proteins to antibiotics in a dark condition and a blue light-irradiated condition. Antibiotics used in the assays were fosfomycin and fosmidomycin. E. coli cells expressing the Naegleria proteins showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light, indicating that the proteins functioned as PACs in the bacterial cells. Analysis of the N. fowleri genome revealed that the organism encodes a protein bearing an amino acid sequence similar to that of BLUF. A plasmid expressing a chimeric protein consisting of the BLUF-like sequence found in N. fowleri and the adenylyl cyclase domain of N. gruberi PAC was constructed to determine whether the BLUF-like sequence functioned as a sensor of blue light. E. coli cells expressing a chimeric protein showed increased fosfomycin sensitivity and fosmidomycin sensitivity when incubated under blue light. These experimental results indicated that the sequence similar to the BLUF domain found in N. fowleri functioned as a sensor of blue light.

Flow diagram of the longitudinal and Hall conductivities in ac regime in the disordered graphene quantum Hall system

We numerically study the behavior of σxy(ω) and σxx (ω) for graphene QHE system in the ac (frequency ω) domain. We interpret these conductivities with the dynamical scaling analysis. We also discuss the temperature flow of σxy(ω) — σxx(ω) diagram for graphene QHE system in the ac region.

Evaluation of preharvest sprouting traits in a collection of spring wheat germplasm using genotype and genotype × environment interaction model

With 10 tablesAbstractPreharvest sprouting (PHS) can greatly affect the consistent production of high‐quality spring wheat (Triticum aestivum L.) in many regions worldwide including Western Canada. A worldwide collection of red‐ and white‐seeded spring wheat genotypes with different levels of sprouting response were characterized for three PHS traits: falling number, germination index and sprouting index in three different environments in Manitoba, Canada. The data sets were analysed by the genotype and genotype × environment interaction model. Variance components were estimated, genotypic and their interaction effects with environments were predicted by using one of mixed linear model approaches: minimum norm quadratic unbiased estimation approach. Genotypic variance expressed as proportion to the phenotypic variance was higher compared to genotype × environment (G × E) interaction effects for all three PHS traits, suggesting that these genotypes can be used to develop high level of PHS‐resistant cultivars regardless of environment. Strong correlations between PHS traits across environments suggest that all three traits are repeatable and reliable methods to determine PHS response in spring wheat depending on sample types (spike, grain or flour). Predicted genotypic effects, G × E interaction effects and the linear discriminant analysis revealed that white‐seeded genotypes ‘AUS1408’, ‘SC8019‐R1’ and Kanata, and red‐seeded genotypes ‘AC Domain’, ‘AC Majestic’ and ‘Red RL4137’ would be useful PHS‐resistant donors in spring wheat cultivar development programmes.

FLAVOR PROPERTIES OF PAN AND PITA BREADS MADE FROM RED AND WHITE HARD SPRING WHEATS

ABSTRACTRed and white wheat comparisons have not always shown consistent flavor differences. The objective was to compare flavor properties of whole wheat pan and pita breads made from white and red Canadian hard spring wheats. Flavor attributes were defined by trained panelists who marked intensities using 15‐cm line scales. Pan bread made from BW275 and Kanata had significantly lower wheat and wheaty aftertaste intensity than AC Domain (red) and RL4863. Pita bread from Kanata had significantly higher sweet intensity than RL4858, Snowbird and AC Domain (red). Principal component analysis accounted for 74–75% of the variance in both bread types. Biplots showed that some of the white wheat breads tended to be sweeter with less wheaty and bitter with wheaty, bitter and sour aftertastes. Red wheat breads tended to be less sweet, more wheaty and bitter with wheaty, bitter and sour aftertastes. Higher wheaty flavor intensity was associated with visually darker breads.PRACTICAL APPLICATIONSThe study revealed that there were distinct flavor differences in pan bread and pita bread made from red and white wheats. The sweeter and milder flavor observed for some white wheats could be a marketing advantage for these newly developed wheats. In pan and pita bread products targeted to consumers that dislike the often wheaty and bitter taste of whole wheat products made from red wheat, white wheat derived whole wheat products with their milder taste may be more acceptable.