Preclinical characterization of pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor.

Bruton tyrosine kinase (BTK), a nonreceptor tyrosine kinase, is a major therapeutic target for B-cell-driven malignancies. However, approved covalent BTK inhibitors (cBTKis) are associated with treatment limitations because of off-target side effects, suboptimal oral pharmacology, and development of resistance mutations (eg, C481) that prevent inhibitor binding. Here, we describe the preclinical profile of pirtobrutinib, a potent, highly selective, noncovalent (reversible) BTK inhibitor. Pirtobrutinib binds BTK with an extensive network of interactions to BTK and water molecules in the adenosine triphosphate binding region and shows no direct interaction with C481. Consequently, pirtobrutinib inhibits both BTK and BTK C481 substitution mutants in enzymatic and cell-based assays with similar potencies. In differential scanning fluorimetry studies, BTK bound to pirtobrutinib exhibited a higher melting temperature than cBTKi-bound BTK. Pirtobrutinib, but not cBTKis, prevented Y551 phosphorylation in the activation loop. These data suggest that pirtobrutinib uniquely stabilizes BTK in a closed, inactive conformation. Pirtobrutinib inhibits BTK signaling and cell proliferation in multiple B-cell lymphoma cell lines, and significantly inhibits tumor growth in human lymphoma xenografts in vivo. Enzymatic profiling showed that pirtobrutinib was highly selective for BTK in >98% of the human kinome, and in follow-up cellular studies pirtobrutinib retained >100-fold selectivity over other tested kinases. Collectively, these findings suggest that pirtobrutinib represents a novel BTK inhibitor with improved selectivity and unique pharmacologic, biophysical, and structural attributes with the potential to treat B-cell-driven cancers with improved precision and tolerability. Pirtobrutinib is being tested in phase 3 clinical studies for a variety of B-cell malignancies.

APETALA2 functions as a temporal factor together with BLADE-ON-PETIOLE2 and MADS29 to control flower and grain development in barley.

Cereal grain develops from fertilised florets. Alterations in floret and grain development greatly influence grain yield and quality. Despite this, little is known about the underlying genetic control of these processes, especially in key temperate cereals such as barley and wheat. Using a combination of near-isogenic mutant comparisons, gene editing and genetic analyses, we reveal that HvAPETALA2 (HvAP2) controls floret organ identity, floret boundaries, and maternal tissue differentiation and elimination during grain development. These new roles of HvAP2 correlate with changes in grain size and HvAP2-dependent expression of specific HvMADS-box genes, including the B-sister gene, HvMADS29 Consistent with this, gene editing demonstrates that HvMADS29 shares roles with HvAP2 in maternal tissue differentiation. We also discovered that a gain-of-function HvAP2 allele masks changes in floret organ identity and grain size due to loss of barley LAXATUM.A/BLADE-ON-PETIOLE2 (HvBOP2) gene function. Taken together, we reveal novel pleiotropic roles and regulatory interactions for an AP2-like gene controlling floret and grain development in a temperate cereal.

An Examination of Self-Employed Nursing Regulation in Three Canadian Provinces.

The COVID-19 pandemic and its related stresses such as short-staffing, heavy workloads, and burnout are prompting nurses to re-consider institutional employment, bringing a renewed interest in self-employed nursing and its regulation. There is limited research on the regulation of self-employed nursing roles, and published work focuses on nurses' experiences rather than on regulatory practices themselves. This qualitative case study research aimed to examine the regulation of self-employed nurses by comparing the regulatory policies and processes of nursing regulatory bodies in Ontario, Alberta, and Saskatchewan. The findings demonstrated wide variation in the regulation of self-employed nurses across these jurisdictions. The article includes recommendations to clarify and harmonize the processes used to regulate self-employed nurses.

Real-world cost-effectiveness of primary prophylaxis with G-CSF biosimilars in patients at intermediate/high risk of febrile neutropenia.

Background: Real-world data suggests superiority of pegfilgrastim (PEG) over filgrastim (FIL) in reducing the incidence of chemotherapy-induced febrile neutropenia (FN), probably attributable to underdosed FIL in practice. We used real-world data to assess the cost-effectiveness of primary prophylaxis with PEG versus FIL in cancer patients at intermediate-to-high risk of FN from a US payer perspective. Methods: A Markov model with lifetime horizon. Results: For the high-risk group, PEG (vs FIL) biosimilars resulted in 0.43 FN events prevented (FNp), 0.27 quality-adjusted life-years gained (QALYg) and a cost saving of USD$5703. For the intermediate-risk group, PEG biosimilar led to 0.18 FNp and 0.12 QALYg, at USD$9674/FNp and USD$14,502/QALYg. Conclusion: PEG biosimilars may provide opportunities to optimize FN management in patients with intermediate-to-high FN risk.

Our results have demonstrated that, by taking the real-world dosing and effectiveness of pegfilgrastim versus filgrastim into account, pegfilgrastim biosimilars have the potential to financially optimize neutropenia management in cancer patients by reducing febrile neutropenia (FN) incidence and FN-related healthcare resource utilization, and to potentially improve health outcomes. Extending primary prophylaxis with pegfilgrastim biosimilars from cancer patients with high-to-intermediate risk of FN resulted in clinical benefits, at acceptable incremental costs. Given the accelerated availability of pegfilgrastim biosimilars, it is important to instigate a rethink of FN management in cancer patients and implement guidelines that maximize the benefits of pegfilgrastim both clinically and economically.

Implementation of a Virtual Asynchronous Scribe Program to Reduce Physician Burnout.

GOAL: Administrative burden is one of many potential root causes of physician burnout. Scribe documentation assistance can reduce this burden. However, traditional in-person scribe services are challenged by consistent staffing because the model requires the physical presence of a scribe and limits the team to a single individual. In addition, in-person scribes cannot provide the flexible support required for virtual care encounters, which can now pivot geographically and temporally. To respond to these challenges, our health network implemented an asynchronous virtual scribe model and evaluated the program's impact on clinician perceptions of burnout across multiple outpatient specialties. METHODS: Using a mixed-methods, pre-/postdesign, this evaluation measured the impact of an asynchronous virtual scribe program on physician burnout. Physicians were given the Professional Fulfillment Index tool (to self-assess their mental state) and free-text comment surveys before virtual scribe initiation and again at 3-, 6-, and 12-month intervals after program implementation. Descriptive statistics of survey results and qualitative review of free-text entries were analyzed for themes of facilitation and barriers to virtual scribe use. PRINCIPAL FINDINGS: Of 50 physician participants in this study, 42 (84%) completed the preintervention survey and 15 (36%) completed all 4 surveys; 25 participants (50%) discontinued scribe use after 12 months. Burnout levels-as defined by dread, exhaustion, lack of enthusiasm, decrease in empathy, and decrease in colleague connection-all trended toward improvement during this study. Importantly, quality, time savings, burnout, and productivity moved in positive directions as well. PRACTICAL APPLICATION: The cost burden to physicians and the COVID-19 pandemic inhibited the continued use of asynchronous virtual medical scribes. Nevertheless, those who continued in the program have reported positive outcomes, which indicates that the service can be a viable and effective tool to reduce physician burnout.

Targeted mutation of barley (1,3;1,4)-ß-glucan synthases reveals complex relationships between the storage and cell wall polysaccharide content.

Barley (Hordeum vulgare L) grain is comparatively rich in (1,3;1,4)-ß-glucan, a source of fermentable dietary fibre that protects against various human health conditions. However, low grain (1,3;1,4)-ß-glucan content is preferred for brewing and distilling. We took a reverse genetics approach, using CRISPR/Cas9 to generate mutations in members of the Cellulose synthase-like (Csl) gene superfamily that encode known (HvCslF6 and HvCslH1) and putative (HvCslF3 and HvCslF9) (1,3;1,4)-ß-glucan synthases. Resultant mutations ranged from single amino acid (aa) substitutions to frameshift mutations causing premature stop codons, and led to specific differences in grain morphology, composition and (1,3;1,4)-ß-glucan content. (1,3;1,4)-ß-Glucan was absent in the grain of cslf6 knockout lines, whereas cslf9 knockout lines had similar (1,3;1,4)-ß-glucan content to wild-type (WT). However, cslf9 mutants showed changes in the abundance of other cell-wall-related monosaccharides compared with WT. Thousand grain weight (TGW), grain length, width and surface area were altered in cslf6 knockouts, and to a lesser extent TGW in cslf9 knockouts. cslf3 and cslh1 mutants had no effect on grain (1,3;1,4)-ß-glucan content. Our data indicate that multiple members of the CslF/H family fulfil important functions during grain development but, with the exception of HvCslF6, do not impact the abundance of (1,3;1,4)-ß-glucan in mature grain.

TERMINAL FLOWER-1/CENTRORADIALIS inhibits tuberisation via protein interaction with the tuberigen activation complex.

Potato tuber formation is a secondary developmental programme by which cells in the subapical stolon region divide and radially expand to further differentiate into starch-accumulating parenchyma. Although some details of the molecular pathway that signals tuberisation are known, important gaps in our knowledge persist. Here, the role of a member of the TERMINAL FLOWER 1/CENTRORADIALIS gene family (termed StCEN) in the negative control of tuberisation is demonstrated for what is thought to be the first time. It is shown that reduced expression of StCEN accelerates tuber formation whereas transgenic lines overexpressing this gene display delayed tuberisation and reduced tuber yield. Protein-protein interaction studies (yeast two-hybrid and bimolecular fluorescence complementation) demonstrate that StCEN binds components of the recently described tuberigen activation complex. Using transient transactivation assays, we show that the StSP6A tuberisation signal is an activation target of the tuberigen activation complex, and that co-expression of StCEN blocks activation of the StSP6A gene by StFD-Like-1. Transcriptomic analysis of transgenic lines misexpressing StCEN identifies early transcriptional events in tuber formation. These results demonstrate that StCEN suppresses tuberisation by directly antagonising the function of StSP6A in stolons, identifying StCEN as a breeding marker to improve tuber initiation and yield through the selection of genotypes with reduced StCEN expression.

Hemoglobin matters: Perioperative blood management for oncology patients.

As the number of cancer cases rise each year in Canada, so does the number of surgical oncology cases. Surgery presents a unique and heightened stressor for the body already experiencing volatility from factors such as disease and treatments. Perioperative red blood cell (RBC) transfusions are critical to stabilize hemoglobin levels and correct anemia, as well as provide a buffer against anticipated intraoperative blood loss. Thoroughly examining and anticipating risk factors related to the potential need for perioperative blood transfusions is necessary to improve outcomes. Research evidence in recent years related to perioperative blood management of oncology patients has specifically recommended active, coordinated programs to reduce the need and amount of blood transfusions administered pre-, intra-, and post-surgery. Coordination between surgical oncologists and a local or provincial patient blood management (PBM) program is an important strategy that allows patients at risk of perioperative complications to be identified and receive early interventions and ongoing observation.

An aphid effector promotes barley susceptibility through suppression of defence gene expression.

Aphids secrete diverse repertoires of effectors into their hosts to promote the infestation process. While 'omics' approaches facilitated the identification and comparison of effector repertoires from a number of aphid species, the functional characterization of these proteins has been limited to dicot (model) plants. The bird cherry-oat aphid Rhopalosiphum padi is a pest of cereal crops, including barley. Here, we extend efforts to characterize aphid effectors with regard to their role in promoting susceptibility to the R. padi-barley interaction. We selected three R. padi effectors based on sequence similarity to previously characterized Myzus persicae effectors and assessed their subcellular localization, expression, and role in promoting plant susceptibility. Expression of R. padi effectors RpC002 and Rp1 in transgenic barley lines enhanced plant susceptibility to R. padi but not M. persicae, for which barley is a poor host. Characterization of Rp1 transgenic barley lines revealed reduced gene expression of plant hormone signalling genes relevant to plant-aphid interactions, indicating that this effector enhances susceptibility by suppressing plant defences in barley. Our data suggest that some aphid effectors specifically function when expressed in host species, and feature activities that benefit their corresponding aphid species.

RNAi-suppression of barley caffeic acid O-methyltransferase modifies lignin despite redundancy in the gene family.

Caffeic acid O-methyltransferase (COMT), the lignin biosynthesis gene modified in many brown-midrib high-digestibility mutants of maize and sorghum, was targeted for downregulation in the small grain temperate cereal, barley (Hordeum vulgare), to improve straw properties. Phylogenetic and expression analyses identified the barley COMT orthologue(s) expressed in stems, defining a larger gene family than in brachypodium or rice with three COMT genes expressed in lignifying tissues. RNAi significantly reduced stem COMT protein and enzyme activity, and modestly reduced stem lignin content while dramatically changing lignin structure. Lignin syringyl-to-guaiacyl ratio was reduced by ~50%, the 5-hydroxyguaiacyl (5-OH-G) unit incorporated into lignin at 10--15-fold higher levels than normal, and the amount of p-coumaric acid ester-linked to cell walls was reduced by ~50%. No brown-midrib phenotype was observed in any RNAi line despite significant COMT suppression and altered lignin. The novel COMT gene family structure in barley highlights the dynamic nature of grass genomes. Redundancy in barley COMTs may explain the absence of brown-midrib mutants in barley and wheat. The barley COMT RNAi lines nevertheless have the potential to be exploited for bioenergy applications and as animal feed.

desynaptic5 carries a spontaneous semi-dominant mutation affecting Disrupted Meiotic cDNA 1 in barley.

Despite conservation of the process of meiosis, recombination landscapes vary between species, with large genome grasses such as barley (Hordeum vulgare L.) exhibiting a pattern of recombination that is very heavily skewed to the ends of chromosomes. We have been using a collection of semi-sterile desynaptic meiotic mutant lines to help elucidate how recombination is controlled in barley and the role of the corresponding wild-type (WT) meiotic genes within this process. Here we applied a combination of genetic segregation analysis, cytogenetics, and immunocytology to genetically map and characterize the meiotic mutant desynaptic5 (des5). We identified an exonic insertion in the positional candidate ortholog of Disrupted Meiotic cDNA 1 (HvDMC1) on chromosome 5H of des5. des5 exhibits a severe meiotic phenotype with disturbed synapsis, reduced crossovers, and chromosome mis-segregation. The meiotic phenotype and reduced fertility of des5 is similarly observed in Hvdmc1RNAi transgenic plants and HvDMC1p:GusPlus reporter lines show DMC1 expression specifically in the developing inflorescence. The des5 mutation maintains the reading frame of the gene and exhibits semi-dominance with respect to recombination in the heterozygote indicating the value of non-knockout mutations for dissection of the control of recombination in the early stages of meiosis.

ACC/AHA Special Report: Clinical Practice Guideline Implementation Strategies: A Summary of Systematic Reviews by the NHLBI Implementation Science Work Group: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines.

BACKGROUND: In 2008, the National Heart, Lung, and Blood Institute convened an Implementation Science Work Group to assess evidence-based strategies for effectively implementing clinical practice guidelines. This was part of a larger effort to update existing clinical practice guidelines on cholesterol, blood pressure, and overweight/obesity. OBJECTIVES: Review evidence from the published implementation science literature and identify effective or promising strategies to enhance the adoption and implementation of clinical practice guidelines. METHODS: This systematic review was conducted on 4 critical questions, each focusing on the adoption and effectiveness of 4 intervention strategies: (1) reminders, (2) educational outreach visits, (3) audit and feedback, and (4) provider incentives. A scoping review of the Rx for Change database of systematic reviews was used to identify promising guideline implementation interventions aimed at providers. Inclusion and exclusion criteria were developed a priori for each question, and the published literature was initially searched up to 2012, and then updated with a supplemental search to 2015. Two independent reviewers screened the returned citations to identify relevant reviews and rated the quality of each included review. RESULTS: Audit and feedback and educational outreach visits were generally effective in improving both process of care (15 of 21 reviews and 12 of 13 reviews, respectively) and clinical outcomes (7 of 12 reviews and 3 of 5 reviews, respectively). Provider incentives showed mixed effectiveness for improving both process of care (3 of 4 reviews) and clinical outcomes (3 reviews equally distributed between generally effective, mixed, and generally ineffective). Reminders showed mixed effectiveness for improving process of care outcomes (27 reviews with 11 mixed and 3 generally ineffective results) and were generally ineffective for clinical outcomes (18 reviews with 6 mixed and 9 generally ineffective results). Educational outreach visits (2 of 2 reviews), reminders (3 of 4 reviews), and provider incentives (1 of 1 review) were generally effective for cost reduction. Educational outreach visits (1 of 1 review) and provider incentives (1 of 1 review) were also generally effective for cost-effectiveness outcomes. Barriers to clinician adoption or adherence to guidelines included time constraints (8 reviews/overviews); limited staffing resources (2 overviews); timing (5 reviews/overviews); clinician skepticism (5 reviews/overviews); clinician knowledge of guidelines (4 reviews/overviews); and higher age of the clinician (1 overview). Facilitating factors included guideline characteristics such as format, resources, and end-user involvement (6 reviews/overviews); involving stakeholders (5 reviews/overviews); leadership support (5 reviews/overviews); scope of implementation (5 reviews/overviews); organizational culture such as multidisciplinary teams and low-baseline adherence (9 reviews/overviews); and electronic guidelines systems (3 reviews). CONCLUSION: The strategies of audit and feedback and educational outreach visits were generally effective in improving both process of care and clinical outcomes. Reminders and provider incentives showed mixed effectiveness, or were generally ineffective. No general conclusion could be reached about cost effectiveness, because of limitations in the evidence. Important gaps exist in the evidence on effectiveness of implementation interventions, especially regarding clinical outcomes, cost effectiveness and contextual issues affecting successful implementation.

Engineering heat tolerance in potato by temperature-dependent expression of a specific allele of HEAT-SHOCK COGNATE 70.

For many commercial potato cultivars, tuber yield is optimal at average daytime temperatures in the range of 14-22 °C. Further rises in ambient temperature can reduce or completely inhibit potato tuber production, with damaging consequences for both producer and consumer. The aim of this study was to use a genetic screen based on a model tuberization assay to identify quantitative trait loci (QTL) associated with enhanced tuber yield. A candidate gene encoding HSc70 was identified within one of the three QTL intervals associated with elevated yield in a Phureja-Tuberosum hybrid diploid potato population (06H1). A particular HSc70 allelic variant was linked to elevated yield in the 06H1 progeny. Expression of this allelic variant was much higher than other alleles, particularly on exposure to moderately elevated temperature. Transient expression of this allele in Nicotiana benthamiana resulted in significantly enhanced tolerance to elevated temperature. An TA repeat element was present in the promoter of this allele, but not in other HSc70 alleles identified in the population. Expression of the HSc70 allelic variant under its native promoter in the potato cultivar Desiree resulted in enhanced HSc70 expression at elevated temperature. This was reflected in greater tolerance to heat stress as determined by improved yield under moderately elevated temperature in a model nodal cutting tuberization system and in plants grown from stem cuttings. Our results identify HSc70 expression level as a significant factor influencing yield stability under moderately elevated temperature and identify specific allelic variants of HSc70 for the induction of thermotolerance via conventional introgression or molecular breeding approaches.

Reducing Stomatal Density in Barley Improves Drought Tolerance without Impacting on Yield.

The epidermal patterning factor (EPF) family of secreted signaling peptides regulate the frequency of stomatal development in model dicot and basal land plant species. Here, we identify and manipulate the expression of a barley (Hordeum vulgare) ortholog and demonstrate that when overexpressed HvEPF1 limits entry to, and progression through, the stomatal development pathway. Despite substantial reductions in leaf gas exchange, barley plants with significantly reduced stomatal density show no reductions in grain yield. In addition, HvEPF1OE barley lines exhibit significantly enhanced water use efficiency, drought tolerance, and soil water conservation properties. Our results demonstrate the potential of manipulating stomatal frequency for the protection and optimization of cereal crop yields under future drier environments.

RXLR Effector AVR2 Up-Regulates a Brassinosteroid-Responsive bHLH Transcription Factor to Suppress Immunity.

An emerging area in plant research focuses on antagonism between regulatory systems governing growth and immunity. Such cross talk represents a point of vulnerability for pathogens to exploit. AVR2, an RXLR effector secreted by the potato blight pathogen Phytophthora infestans, interacts with potato BSL1, a putative phosphatase implicated in growth-promoting brassinosteroid (BR) hormone signaling. Transgenic potato (Solanum tuberosum) plants expressing the effector exhibit transcriptional and phenotypic hallmarks of overactive BR signaling and show enhanced susceptibility to P. infestans Microarray analysis was used to identify a set of BR-responsive marker genes in potato, all of which are constitutively expressed to BR-induced levels in AVR2 transgenic lines. One of these genes was a bHLH transcription factor, designated StCHL1, homologous to AtCIB1 and AtHBI1, which are known to facilitate antagonism between BR and immune responses. Transient expression of either AVR2 or CHL1 enhanced leaf colonization by P. infestans and compromised immune cell death activated by perception of the elicitin Infestin1 (INF1). Knockdown of CHL1 transcript using Virus-Induced Gene Silencing (VIGS) reduced colonization of P. infestans on Nicotiana benthamiana Moreover, the ability of AVR2 to suppress INF1-triggered cell death was attenuated in NbCHL1-silenced plants, indicating that NbCHL1 was important for this effector activity. Thus, AVR2 exploits cross talk between BR signaling and innate immunity in Solanum species, representing a novel, indirect mode of innate immune suppression by a filamentous pathogen effector.

MET-targeting antibody (emibetuzumab) and kinase inhibitor (merestinib) as single agent or in combination in a cancer model bearing MET exon 14 skipping.

Purpose Approximately 3% of lung cancer bears mutations leading to MET exon 14 skipping, an oncogenic driver which is further evidenced by case reports of patient response to MET kinase inhibitor treatment. Approximately 15% of tumors harboring MET exon14 skipping have concurrent MET amplification. Experimental Design Merestinib is a type II MET kinase inhibitor. Emibetuzumab, a bivalent anti-MET antibody, internalizes MET receptor. Each single agent and the combination were evaluated in the Hs746t gastric cancer line bearing MET exon14 skipping and MET amplification. Results Merestinib inhibited Hs746t cell proliferation (IC50=34 nM) and totally eliminated pMET at 100nM. Emibetuzumab showed little anti-proliferative activity against Hs746t cells (IC50>100nM), did not reduce pMET, and slightly reduced cell surface MET. In the Hs746t xenograft model, dose dependent differences in durability of response were seen with merestinib including durable tumor regression (91.8%) at 12 mg/kg qd. Emibetuzumab treatment (10mg/kg qw) provided transient tumor regression (37.7%), but tumors re-grew while on treatment. Concurrent combination of merestinib (6 mg/kg qd) and emibetuzumab resulted in 85% tumor regression, while a sequential combination (initiating merestinib first) resulted in longer duration of treatment response. Conclusions Data in this study support a clinical evaluation of merestinib in patients with MET exon 14 skipping (NCT02920996). As a type II MET kinase inhibitor, merestinib may provide a therapeutic option to treatment naïve patients or to patients who progress on type I MET inhibitor treatment. Data also support clinical evaluation of the sequential combination of merestinib with emibetuzumab when patients progress on single agent merestinib.

Changes in medical student implicit attitudes following a health equity curricular intervention.

PURPOSE: This study assessed the: (1) effect of an LGBTQI + health equity curriculum (eQuality) on implicit attitudes among first (M1) and second year (M2) medical students and (2) utility of dedicated time to explore implicit bias. METHOD: Implicit biases were assessed at baseline using implicit association tests (IAT) for all M2s and a random sample of first years (M1A). These students were then debriefed on strategies to mitigate bias. Following eQuality, all M1 and M2s completed post-intervention IATs. The remaining first years (M1B) were then debriefed. Paired sample t-tests assessed differences between pre/post. Independent sample t-tests assessed differences in post-IATs between M1 groups. RESULTS: IATs indicated preferences for "Straight," "White," and "Thin" at both pre and post. M2s demonstrated statistically significant improvements pre to post for sexuality (p = 0.01) and race (p = 0.03). There were significant differences in post-intervention IAT scores between M1As who received the IAT and debriefing prior to eQuality and M1Bs for sexuality (p = 0.002) and race (p = 0.046). There were no significant changes for weight. CONCLUSION: eQuality reduced implicit preference for "Straight" and "White." Differences in M1 post-intervention IAT scores between groups suggest dedicating time to debrief implicit attitudes enhances bias mitigation.

The synaptonemal complex protein ZYP1 is required for imposition of meiotic crossovers in barley.

In many cereal crops, meiotic crossovers predominantly occur toward the ends of chromosomes and 30 to 50% of genes rarely recombine. This limits the exploitation of genetic variation by plant breeding. Previous reports demonstrate that chiasma frequency can be manipulated in plants by depletion of the synaptonemal complex protein ZIPPER1 (ZYP1) but conflict as to the direction of change, with fewer chiasmata reported in Arabidopsis thaliana and more crossovers reported for rice (Oryza sativa). Here, we use RNA interference (RNAi) to reduce the amount of ZYP1 in barley (Hordeum vulgare) to only 2 to 17% of normal zygotene levels. In the ZYP1(RNAi) lines, fewer than half of the chromosome pairs formed bivalents at metaphase and many univalents were observed, leading to chromosome nondisjunction and semisterility. The number of chiasmata per cell was reduced from 14 in control plants to three to four in the ZYP1-depleted lines, although the localization of residual chiasmata was not affected. DNA double-strand break formation appeared normal, but the recombination pathway was defective at later stages. A meiotic time course revealed a 12-h delay in prophase I progression to the first labeled tetrads. Barley ZYP1 appears to function similarly to ZIP1/ZYP1 in yeast and Arabidopsis, with an opposite effect on crossover number to ZEP1 in rice, another member of the Poaceae.

Overexpression and Down-Regulation of Barley Lipoxygenase LOX2.2 Affects Jasmonate-Regulated Genes and Aphid Fecundity.

Aphids are pests on many crops and depend on plant phloem sap as their food source. In an attempt to find factors improving plant resistance against aphids, we studied the effects of overexpression and down-regulation of the lipoxygenase gene LOX2.2 in barley (Hordeum vulgare L.) on the performance of two aphid species. A specialist, bird cherry-oat aphid (Rhopalosiphum padi L.) and a generalist, green peach aphid (Myzus persicae Sulzer) were studied. LOX2.2 overexpressing lines showed up-regulation of some other jasmonic acid (JA)-regulated genes, and antisense lines showed down-regulation of such genes. Overexpression or suppression of LOX2.2 did not affect aphid settling or the life span on the plants, but in short term fecundity tests, overexpressing plants supported lower aphid numbers and antisense plants higher aphid numbers. The amounts and composition of released volatile organic compounds did not differ between control and LOX2.2 overexpressing lines. Up-regulation of genes was similar for both aphid species. The results suggest that LOX2.2 plays a role in the activation of JA-mediated responses and indicates the involvement of LOX2.2 in basic defense responses.

Paternal Caregivers' Parenting Practices and Psychological Functioning among African American Youth Living in Urban Public Housing.

Structural factors associated with public housing contribute to living environments that expose families to adverse life events that may in turn directly impact parenting and youth outcomes. However, despite the growth in research on fathers, research on families in public housing has practically excluded fathers and the role fathers play in the well-being of their adolescents. Using a sample of 660 African American adolescents recruited from public housing, we examined the relationship between paternal caregivers' (i.e., fathers' and father figures') parenting practices and adolescents' depressive symptoms, attitudes toward deviance, and self-efficacy. Using a latent profile analysis (LPA), we confirmed a four-class model of paternal parenting practices ranging from high to low levels of monitoring and encouragement. Results from a one-way ANOVA indicated that paternal caregivers with high (compared to moderate) levels of encouragement and monitoring were associated with youth who reported less depressive symptoms, higher levels of self-efficacy, and less favorable attitudes toward deviance. Discriminant analysis results indicated that approximately half of the sample were correctly classified into two paternal caregiver classes. The findings provide evidence that some of these caregivers engage in parenting practices that support youths' psychological functioning. More research is needed to determine what accounts for the variability in levels of paternal encouragement and supervision, including environmental influences, particularly for paternal caregivers exhibiting moderate-to-low levels of paternal encouragement and monitoring.