Micrococcin cysteine-to-thiazole conversion through transient interactions between a scaffolding protein and two modification enzymes

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a broad group of compounds mediating microbial competition in nature. Azole/azoline heterocycle formation in the peptide backbone is a key step in the biosynthesis of many RiPPs. Heterocycle formation in RiPP precursors is often carried out by a scaffold protein, an ATP-dependent cyclodehydratase, and an FMN-dependent dehydrogenase. It has generally been assumed that the orchestration of these modifications is carried out by a stable complex including the scaffold, cyclodehydratase and dehydrogenase. The antimicrobial RiPP micrococcin begins as a precursor peptide (TclE) with a 35-amino acid N-terminal leader and a 14-amino acid C-terminal core containing six Cys residues that are converted to thiazoles. The putative scaffold protein (TclI) presumably presents the TclE substrate to a cyclodehydratase (TclJ) and a dehydrogenase (TclN) to accomplish the two-step installation of the six thiazoles. In this study, we identify a minimal TclE leader region required for thiazole formation, we demonstrate complex formation between TclI, TclJ and TclN, and further define regions of these proteins required for complex formation. Our results point to a mechanism of thiazole installation in which TclI associates with the two enzymes in a mutually exclusive fashion, such that each enzyme competes for access to the peptide substrate in a dynamic equilibrium, thus ensuring complete modification of each Cys residue in the TclE core.

Guidelines for evaluating the conservation value of African lion (Panthera leo) translocations

As the top predator in African ecosystems, lions have lost more than 90% of their historical range, and few countries possess strong evidence for stable populations. Translocations (broadly defined here as the capture and movement of lions for various management purposes) have become an increasingly popular action for this species, but the wide array of lion translocation rationales and subsequent conservation challenges stemming from poorly conceived or unsuitable translocations warrants additional standardized evaluation and guidance. At their best, translocations fill a key role in comprehensive strategies aimed at addressing the threats facing lions and fostering the recovery of wild populations in their historic range. At their worst, translocations can distract from addressing the major threats to wild populations and habitats, divert scarce funding from more valuable conservation actions, exacerbate conflict with humans in recipient sites, disrupt local lion demography, and undermine the genetic integrity of wild lion populations in both source and recipient sites. In the interest of developing best practice guidelines for deciding when and how to conduct lion translocations, we discuss factors to consider when determining whether a translocation is of conservation value, introduce a value assessment for translocations, and provide a decision matrix to assist practitioners in improving the positive and reducing the negative outcomes of lion translocation.

Development of a curriculum integrating biostatistics and study design with core sciences in an organ system block

INTRODUCTION

The objectives of this study were to develop and evaluate a curriculum that integrated biostatistics and research design content with core sciences content within a pharmacy course.

METHODS

An inquiry curriculum was developed in 2019 and included lectures on biostatistics and research design with small group discussions of clinical research papers directly related to the core sciences content. Students' perceptions and pass rates between students who did (2019 cohort) and did not (2018 cohort) undergo the curriculum were compared. Test scores taken approximately one year after completion of each cohort's course were also compared.

RESULTS

Of 127 students in the 2019 cohort, 120 (94%) responded. Over 90% agreed or strongly agreed that inquiry and core sciences contents were integrated well. The 2019 cohort had a significantly higher pass rate than the 2018 cohort on two of three assessment questions evaluated: one multiple choice question (P = .037) and one short answer question (P = .013). After adjustments for baseline characteristics, retention study volunteers from the 2019 cohort had a significantly higher percent test score than those from the 2018 cohort (parameter estimate = 8.48%; P = .026).

CONCLUSIONS

An inquiry curriculum consisting of select biostatistics and research design topics can be integrated with a core sciences curriculum in a large integrated pharmacy course. Inclusion of this content increased student academic performance and retention of knowledge and skills.

Genetic guidelines for translocations: Maintaining intraspecific diversity in the lion (Panthera leo)

Conservation translocations have become an important management tool, particularly for large wildlife species such as the lion (Panthera leo). When planning translocations, the genetic background of populations needs to be taken into account; failure to do so risks disrupting existing patterns of genetic variation, ultimately leading to genetic homogenization, and thereby reducing resilience and adaptability of the species. We urge wildlife managers to include knowledge of the genetic background of source/target populations, as well as species-wide patterns, in any management intervention. We present a hierarchical decision-making tool in which we list 132 lion populations/lion conservation units and provide information on genetic assignment, uncertainty and suitability for translocation for each source/target combination. By including four levels of suitability, from 'first choice' to 'no option', we provide managers with a range of options. To illustrate the extent of international trade of lions, and the potential disruption of natural patterns of intraspecific diversity, we mined the CITES Trade Database for estimated trade quantities of live individuals imported into lion range states during the past 4 decades. We identified 1056 recorded individuals with a potential risk of interbreeding with wild lions, 772 being captive-sourced. Scoring each of the records with our decision-making tool illustrates that only 7% of the translocated individuals were 'first choice' and 73% were 'no option'. We acknowledge that other, nongenetic factors are important in the decision-making process, and hence a pragmatic approach is needed. A framework in which source/target populations are scored based on suitability is not only relevant to lion, but also to other species of wildlife that are frequently translocated. We hope that the presented overview supports managers to include genetics in future management decisions and contributes towards conservation of the lion in its full diversity.

Persistent Barriers to Smoking Cessation Among Urban, Underserved Women: A Feasibility Study of Tailored Barriers Text Messages

OBJECTIVES

Despite health risks for themselves and their children, urban underserved women smoke at high rates postpartum. The postpartum period is a stressful transition time that presents unique barriers to sustained cessation. There is limited extant evidence of efficacious psychosocial programs to maintain postpartum smoking cessation.

METHODS

Guided by the Cognitive-Social Health Information Processing model, we explored the feasibility of TxT2Commit, a text-messaging intervention designed to prevent postpartum smoking relapse. Participants (n = 43) received supportive cessation-focused text messages for one month postpartum. Using a convergent mixed method design, surveys and interviews assessed changes in psychosocial factors and smoking status through a three month follow-up.

RESULTS

Participants reported satisfaction with TxT2Commit, rating text messages as helpful, understandable, supportive, and not bothersome. However, a majority of women (n = 28, 65.1%) relapsed by three months. Participants who stayed smoke free (i.e., non-relapsers) reported significantly less temptation to smoke at one and three months postpartum compared to relapsers (ps < .01). While relapsers had significantly less temptation at one month compared to baseline, temptation increased by three months (p < .01). Consistent with the quantitative results, qualitative interviews identified informational and coping needs, with continued temptation throughout the three months. Non-relapsers were able to manage temptation and reported greater support.

CONCLUSIONS FOR PRACTICE

TxT2Commit demonstrates preliminary feasibility and acceptability among urban, underserved postpartum women. However, most participants relapsed by three months postpartum. Additional research is needed to identify targeted messaging to best help women avoid temptation and bolster support to stay smoke free in this uniquely stressful period.

Informing urban climate planning with high resolution data: the Hestia fossil fuel CO2 emissions for Baltimore, Maryland

BACKGROUND

Cities contribute more than 70% of global anthropogenic carbon dioxide (CO2) emissions and are leading the effort to reduce greenhouse gas (GHG) emissions through sustainable planning and development. However, urban greenhouse gas mitigation often relies on self-reported emissions estimates that may be incomplete and unverifiable via atmospheric monitoring of GHGs. We present the Hestia Scope 1 fossil fuel CO2 (FFCO2) emissions for the city of Baltimore, Maryland-a gridded annual and hourly emissions data product for 2010 through 2015 (Hestia-Baltimore v1.6). We also compare the Hestia-Baltimore emissions to overlapping Scope 1 FFCO2 emissions in Baltimore's self-reported inventory for 2014.

RESULTS

The Hestia-Baltimore emissions in 2014 totaled 1487.3 kt C (95% confidence interval of 1158.9-1944.9 kt C), with the largest emissions coming from onroad (34.2% of total city emissions), commercial (19.9%), residential (19.0%), and industrial (11.8%) sectors. Scope 1 electricity production and marine shipping were each generally less than 10% of the city's total emissions. Baltimore's self-reported Scope 1 FFCO2 emissions included onroad, natural gas consumption in buildings, and some electricity generating facilities within city limits. The self-reported Scope 1 FFCO2 total of 1182.6 kt C was similar to the sum of matching emission sectors and fuels in Hestia-Baltimore v1.6. However, 20.5% of Hestia-Baltimore's emissions were in sectors and fuels that were not included in the self-reported inventory. Petroleum use in buildings were omitted and all Scope 1 emissions from industrial point sources, marine shipping, nonroad vehicles, rail, and aircraft were categorically excluded.

CONCLUSIONS

The omission of petroleum combustion in buildings and categorical exclusions of several sectors resulted in an underestimate of total Scope 1 FFCO2 emissions in Baltimore's self-reported inventory. Accurate Scope 1 FFCO2 emissions, along with Scope 2 and 3 emissions, are needed to inform effective urban policymaking for system-wide GHG mitigation. We emphasize the need for comprehensive Scope 1 emissions estimates for emissions verification and measuring progress towards Scope 1 GHG mitigation goals using atmospheric monitoring.

A-07 The Impact of Learning Disorders on Clinical Measures Following Concussion

Objective

To examine differences in clinical measures between adolescents with dyslexia, ADD/ADHD, and those without a learning disorder (LD) following concussion.

Method

Data from the North Texas Concussion Registry (ConTex) were extracted. Participants ages 10–18 with a diagnosed concussion within 30 days of enrollment were included and categorized based on self-reported prior diagnosis of dyslexia, ADD/ADHD, and no history of LD. ImPACT, King-Devick (KD), SCAT-5 symptom log, Patient Health Questionnaire (PHQ-8), and Generalized Anxiety Disorder (GAD-7) scale were compared between groups using a one-way ANOVA followed by a Tukey test for multiple comparisons.

Results

Of 993 eligible participants, 68 had dyslexia, 141 had ADD/ADHD, and 784 had no history of LD. There were significantly more male participants in the ADD/ADHD group compared to the no LD group (64.5% vs. 50.3%, p = 0.002). No other demographic differences were noted between groups. In the dyslexia group, SCAT-5 symptom score was higher (36.22 vs. 28.27, p = 0.037) and ImPACT visual motor control was lower compared to the no LD group (28.87 vs. 32.99, p = 0.027). In the ADD/ADHD group, ImPACT symptom score was higher (30.69 vs. 20.94, p &lt; 0.001) and visual motor control was lower compared to the no LD group (30.05 vs. 32.99, p = 0.009). KD time (62.1 sec), PHQ-8 (5.79), and GAD-7 (5.06) were higher in the ADD/ADHD group compared to the no LD group (56.5 sec, 4.32, 3.56; p = 0.022, p = 0.003, p = 0.002).

Conclusions

Differences in clinical measures were seen in participants with a history of dyslexia and ADD/ADHD that may aid providers in their evaluation following adolescent concussion.

A pulsed-power implementation of "Laser Gate" for increasing laser energy coupling and fusion yield in magnetized liner inertial fusion (MagLIF)

Magnetized Liner Inertial Fusion (MagLIF) at Sandia National Laboratories involves a laser preheating stage where a few-ns laser pulse passes through a few-micron-thick plastic window to preheat gaseous fusion fuel contained within the MagLIF target. Interactions with this window reduce heating efficiency and mix window and target materials into the fuel. A recently proposed idea called "Laser Gate" involves removing the window well before the preheating laser is applied. In this article, we present experimental proof-of-principle results for a pulsed-power implementation of Laser Gate, where a thin current-carrying wire weakens the perimeter of the window, allowing the fuel pressure to push the window open and away from the preheating laser path. For this effort, transparent targets were fabricated and a test facility capable of studying this version of Laser Gate was developed. A 12-frame bright-field laser schlieren/shadowgraphy imaging system captured the window opening dynamics on microsecond timescales. The images reveal that the window remains largely intact as it opens and detaches from the target. A column of escaping pressurized gas appears to prevent the detached window from inadvertently moving into the preheating laser path.

Optimization of switch diagnostics on the MAIZE linear transformer driver

The MAIZE Linear Transformer Driver consists of 40 capacitor-switch-capacitor "bricks" connected in parallel. When these 40 bricks are charged to ±100-kV and then discharged synchronously, the MAIZE facility generates a 1-MA current pulse with a 100-ns rise time into a matched load impedance. Discharging each of the capacitors in a brick is carried out by the breakdown of a spark-gap switch, a process that results in the emission of light. Monitoring this output light with a fiber optic coupled to a photomultiplier tube (PMT) and an oscilloscope channel provides information on switch performance and timing jitter-whether a switch fired early, late, or in phase with the other switches. However, monitoring each switch with a dedicated detector-oscilloscope channel can be problematic for facilities where the number of switches to be monitored (e.g., 40 on MAIZE) greatly exceeds the number of detector-oscilloscope channels available. The technique of using fibers to monitor light emission from switches can be optimized by treating a PMT as a binary digit or bit and using a combinatorial encoding scheme, where each switch is monitored by a unique combination of fiber-PMT-oscilloscope channels simultaneously. By observing the unique combination of fiber-PMT-oscilloscope channels that are turned on, the prefiring or late-firing of a single switch on MAIZE can be identified by as few as six PMT-oscilloscope channels. The number of PMT-oscilloscope channels, N, required to monitor X switches can be calculated by 2^N = X + 1, where the number "2" is selected because the PMT-oscilloscope acts as a bit. In this paper, we demonstrate the use of this diagnostic technique on MAIZE. We also present an analysis of how this technique could be scaled to monitor the tens of thousands of switches proposed for various next generation pulsed power facilities.

The use of contraceptive techniques in managed wild African lion (Panthera leo) populations to mimic open system cub recruitment

Context Managed wild lions (Panthera leo) are lions found in smaller (&lt;1000 km2), fenced protected areas that hold a substantial portion of South Africa’s wild lion population. Because the natural population control mechanisms are compromised within these properties, managers must actively control population growth rates. Fecundity control is used by wildlife managers, but long-term, empirical data on the impact and consequences of such interventions in lions are lacking. Aims The aim of the present study was to assess the effectiveness of two methods of contraception (deslorelin implant and unilateral hysterectomy) in reducing cub recruitment of managed wild lions. Methods Survey data spanning 14 years from 94 managed wild lions on 19 protected areas were used to evaluate the effectiveness of deslorelin implant treatments and unilateral hysterectomies on population growth rates through mimicking open system cub recruitment. Key results Deslorelin implants were effective at increasing the age of first reproduction and lengthening inter-birth intervals. There was also an unexpected decrease in litter size. Behavioural side-effects were recorded in 40% of individuals: 19% pride fragmentation; 13% lack of receptiveness towards males; 8% other. The more successive deslorelin implants a lioness had, the more likely it was that weight gain was reported. Unilateral hysterectomy resulted in a decrease in litter size post-surgery, but this was not statistically significant. No behavioural or physiological side-effects were noted after unilateral hysterectomy. Conclusions Deslorelin treatment was more effective in reducing the reproductive output of managed wild lionesses than unilateral hysterectomy surgery. While more side-effects were associated with deslorelin implants than unilateral hysterectomies, a single deslorelin treatment is currently a good option for fecundity reduction. More research is required on unilateral hysterectomy surgery. Implications Neither deslorelin implants nor unilateral hysterectomies offer a ‘silver bullet’ solution for reducing rapid population growth in managed wild lions. Reproductive control should be integrated with other best-practice approaches.

"What if she was your mother?" Toward better responses

Critical care physicians may hear a surrogate decision-maker ask, "What would you do if she was your mother?" or "What if your father was this sick?" These kinds of questions ask more of the critical care physician than the surrogate might realize. There are deep-seated ethical, professional, and personal complexities that can challenge critical care physicians to answer these questions with honesty. This essay offers practical guidance for critical care physicians who aim to respond to such queries with honesty and beneficence. We discuss a variety of motivations that can accompany this unique kind of question from a surrogate. The surrogate may be seeking moral guidance-the true question being, "What should I do?" We offer a number of questions that the critical care physician might ask of the surrogate in order to attend to both the surrogate's moral dilemma and the patient's values and preferences for medical interventions. We also offer a number of questions to promote contemplation of these issues by the critical care physician herself. We argue that until the critical care physician: discovers the surrogate's motivation, connects this motivation to patient preferences, and asks herself important questions regarding death and dying, the physician's responses will not adequately attend to the issues prompted by such questions.

Role of comprehension on performance at higher levels of Bloom's taxonomy: Findings from assessments of healthcare professional students

The first four levels of Bloom's taxonomy were used to create quiz questions designed to assess student learning of the gross anatomy, histology, and physiology of the gastrointestinal (GI) system. Information on GI histology and physiology was presented to separate samples of medical, dental, and podiatry students in computer based tutorials where the information from the two disciplines was presented either separately or in an integrated fashion. All students were taught GI gross anatomy prior to this study by course faculty as part of the required curriculum of their respective program. Student responses to the quiz questions were analyzed to assess both the validity of Bloom's cumulative hierarchy and the effectiveness of an integrated curriculum. No statistically significant differences were found between quiz scores from students who received the integrated tutorial and from those who received the separate tutorials. Multiple regression analyses provided partial support for a cumulative hierarchy where scores on the lower levels of Bloom's taxonomy predicted scores on higher levels. Notably, in the majority of regression analyses, the comprehension score was the key foundational predictor for application and analysis scores. This study supports the suggestion that educators increase the number of comprehension level questions, even at the expense of knowledge level questions, in course assessments both to evaluate lower order cognitive skills and also as a predictor of success on questions requiring application and analysis levels of the higher order cognitive skills of Bloom's taxonomy. Anat Sci Educ 11: 433-444. © 2018 American Association of Anatomists.

Six Values Never to Silence: Jewish Perspectives on Nazi Medical Professionalism

An ideological case study based on medical profession norms during the Third Reich will be used to exemplify the importance of diversity in the manifestations of professional ethics. The German professional medical community banned their Jewish colleagues from treating German citizens. This included legally mandated employment discrimination and outright censure which led to a professional ethic devoid of diverse voices. While the escalation to the T-4 program and medicalized genocide was influenced by many causes, the intentional, ethnocentric-based exclusion of voices was an important contributing element to the chronicled degradation of societal mores. For illustration, six core Jewish values-life, peace, justice, mercy, scholarship, and sincerity of intention-will be detailed for their potential to inspire health-care professionals to defend and protect minorities and for readers to think critically about the role of medical professionalism in Third Reich society. The Jewish teachings highlight the inherent professional obligations physicians have toward their patients in contrast to the Third Reich's corruption of patient-centered professionalism. More fundamentally, juxtaposing Jewish and Nazi teachings exposes the loss of perspective when a profession's identity spurns diversity. To ensure respect for persons in all vulnerable minorities, the first step is addressing professional inclusion of minority voices.

Report of the 2016-17 Academic Affairs Standing Committee: Entrustable Professional Activities Implementation Roadmap

The purpose of this report is to: 1) Identify linkages across the EPA statements, Center for the Advancement of Pharmacy Education 2013 Educational Outcomes (CAPE 2013) and the Joint Commission of Pharmacy Practitioners' Pharmacist Patient Care Process (PPCP); 2) Provide ways EPA statements can be used to communicate core skills that are part of the entry-level pharmacist identity; 3) Suggest a potential roadmap for AACP members on how to implement EPA statements.

Scaling the Construct Androgyny: Reply to Willemsen

Miller and Kottke reply to Willemsen's 1993 critique of Kottke's 1988 paper. We believe that Willemsen may have overstated the purpose of Kottke's study Kottke's intention was not to develop a new measure of androgyny or to provide a definitive answer to whether masculinity and femininity are bipolar concepts but rather to show that the concept of androgyny requires additional theoretical and empirical clarification, particularly in its measurement.

Rehabilitation Counseling Students' Attitudes Toward People with Disabilities in Three Social Contexts

This article examined factors influencing rehabilitation counseling students' attitudes toward people with disabilities in three social contexts, using a conjoint analysis design. A total of 98 graduate students participated in this study. A conjoint measurement of 38 cards (representing people with varying disability type, gender, ethnicity, age, education, and employment status) was used. The authors found that (a) disability-related factors were heavily involved in the preference-making process, (b) attitude or preference formation was also significantly affected by other client characteristics unrelated to disability, and (c) factors influencing attitude/preference formation were similar across the three social contexts. Conjoint analysis could increase our ability to understand factors contributing to the formation of attitudes/preferences in multiple social contexts.

Organic and inorganic mercurials have distinct effects on cellular thiols, metal homeostasis, and Fe-binding proteins in Escherichia coli

The protean chemical properties of the toxic metal mercury (Hg) have made it attractive in diverse applications since antiquity. However, growing public concern has led to an international agreement to decrease its impact on health and the environment. During a recent proteomics study of acute Hg exposure in E. coli, we also examined the effects of inorganic and organic Hg compounds on thiol and metal homeostases. On brief exposure, lower concentrations of divalent inorganic mercury Hg(II) blocked bulk cellular thiols and protein-associated thiols more completely than higher concentrations of monovalent organomercurials, phenylmercuric acetate (PMA) and merthiolate (MT). Cells bound Hg(II) and PMA in excess of their available thiol ligands; X-ray absorption spectroscopy indicated nitrogens as likely additional ligands. The mercurials released protein-bound iron (Fe) more effectively than common organic oxidants and all disturbed the Na(+)/K(+) electrolyte balance, but none provoked efflux of six essential transition metals including Fe. PMA and MT made stable cysteine monothiol adducts in many Fe-binding proteins, but stable Hg(II) adducts were only seen in CysXxx(n)Cys peptides. We conclude that on acute exposure: (a) the distinct effects of mercurials on thiol and Fe homeostases reflected their different uptake and valences; (b) their similar effects on essential metal and electrolyte homeostases reflected the energy dependence of these processes; and (c) peptide phenylmercury-adducts were more stable or detectable in mass spectrometry than Hg(II)-adducts. These first in vivo observations in a well-defined model organism reveal differences upon acute exposure to inorganic and organic mercurials that may underlie their distinct toxicology.

Establishing disease causality for a novel gene variant in familial dilated cardiomyopathy using a functional in-vitro assay of regulated thin filaments and human cardiac myosin

Background

As next generation sequencing for the genetic diagnosis of cardiovascular disorders becomes more widely used, establishing causality for putative disease causing variants becomes increasingly relevant. Diseases of the cardiac sarcomere provide a particular challenge in this regard because of the complexity of assaying the effect of genetic variants in human cardiac contractile proteins.

Results

In this study we identified a novel variant R205Q in the cardiac troponin T gene (TNNT2). Carriers of the variant allele exhibited increased chamber volumes associated with decreased left ventricular ejection fraction. To clarify the causal role of this variant, we generated recombinant variant human protein and examined its calcium kinetics as well as the maximally activated ADP release of human β-cardiac myosin with regulated thin filaments containing the mutant troponin T. We found that the R205Q mutation significantly decreased the calcium sensitivity of the thin filament by altering the effective calcium dissociation kinetics.

Conclusions

The development of moderate throughput post-genomic assays is an essential step in the realization of the potential of next generation sequencing. Although technically challenging, biochemical and functional assays of human cardiac contractile proteins of the thin filament can be achieved and provide an orthogonal source of information to inform the question of causality for individual variants.

Structure and dynamics of a compact state of a multidomain protein, the mercuric ion reductase

The functional efficacy of colocalized, linked protein domains is dependent on linker flexibility and system compaction. However, the detailed characterization of these properties in aqueous solution presents an enduring challenge. Here, we employ a novel, to our knowledge, combination of complementary techniques, including small-angle neutron scattering, neutron spin-echo spectroscopy, and all-atom molecular dynamics and coarse-grained simulation, to identify and characterize in detail the structure and dynamics of a compact form of mercuric ion reductase (MerA), an enzyme central to bacterial mercury resistance. MerA possesses metallochaperone-like N-terminal domains (NmerA) tethered to its catalytic core domain by linkers. The NmerA domains are found to interact principally through electrostatic interactions with the core, leashed by the linkers so as to subdiffuse on the surface over an area close to the core C-terminal Hg(II)-binding cysteines. How this compact, dynamical arrangement may facilitate delivery of Hg(II) from NmerA to the core domain is discussed.

X-ray structure of a Hg2+ complex of mercuric reductase (MerA) and quantum mechanical/molecular mechanical study of Hg2+ transfer between the C-terminal and buried catalytic site cysteine pairs

Mercuric reductase, MerA, is a key enzyme in bacterial mercury resistance. This homodimeric enzyme captures and reduces toxic Hg²⁺ to Hg⁰, which is relatively unreactive and can exit the cell passively. Prior to reduction, the Hg²⁺ is transferred from a pair of cysteines (C558′ and C559′ using Tn501 numbering) at the C-terminus of one monomer to another pair of cysteines (C136 and C141) in the catalytic site of the other monomer. Here, we present the X-ray structure of the C-terminal Hg²⁺ complex of the C136A/C141A double mutant of the Tn501 MerA catalytic core and explore the molecular mechanism of this Hg transfer with quantum mechanical/molecular mechanical (QM/MM) calculations. The transfer is found to be nearly thermoneutral and to pass through a stable tricoordinated intermediate that is marginally less stable than the two end states. For the overall process, Hg²⁺ is always paired with at least two thiolates and thus is present at both the C-terminal and catalytic binding sites as a neutral complex. Prior to Hg²⁺ transfer, C141 is negatively charged. As Hg²⁺ is transferred into the catalytic site, a proton is transferred from C136 to C559′ while C558′ becomes negatively charged, resulting in the net transfer of a negative charge over a distance of ∼7.5 Å. Thus, the transport of this soft divalent cation is made energetically feasible by pairing a competition between multiple Cys thiols and/or thiolates for Hg²⁺ with a competition between the Hg²⁺ and protons for the thiolates.

Evaluation of microsatellite markers for populations studies and forensic identification of African lions (Panthera leo)

The South African lion (Panthera leo) population is highly fragmented. One-third of its wild lions occur in small (<1000 km(2)) reserves. These lions were reintroduced from other areas of the species' historical range. Management practices on these reserves have not prioritized genetic provenance or heterozygosity. These trends potentially constrain the conservation value of these lions. To ensure the best management and long-term survival of these subpopulations as a viable collective population, the provenance and current genetic diversity must be described. Concurrently, poaching of lions to supply a growing market for lion bones in Asia may become a serious conservation challenge in the future. Having a standardized, validated method for matching confiscated lion parts with carcasses will be a key tool in investigating these crimes. We evaluated 28 microsatellites in the African lion using samples from 18 small reserves and 1 captive facility in South Africa, two conservancies in Zimbabwe, and Kruger National and Kgalagadi Transfrontier Parks to determine the loci most suited for population management and forensic genetic applications. Twelve microsatellite loci with a match probability of 1.1×10(-5) between siblings were identified for forensics. A further 10 could be added for population genetics studies.

Attitudinal barriers to participation in oncology clinical trials: factor analysis and correlates of barriers

Patient participation in cancer clinical trials is low. Little is known about attitudinal barriers to participation, particularly among patients who may be offered a trial during an imminent initial oncology consult. The aims of the present study were to confirm the presence of proposed subscales of a recently developed cancer clinical trial attitudinal barriers measure, describe the most common cancer clinical trials attitudinal barriers, and evaluate socio-demographic, medical and financial factors associated with attitudinal barriers. A total of 1256 patients completed a survey assessing demographic factors, perceived financial burden, prior trial participation and attitudinal barriers to clinical trials participation. Results of a factor analysis did not confirm the presence of the proposed four attitudinal barriers subscale/factors. Rather, a single factor represented the best fit to the data. The most highly-rated barriers were fear of side-effects, worry about health insurance and efficacy concerns. Results suggested that less educated patients, patients with non-metastatic disease, patients with no previous oncology clinical trial participation, and patients reporting greater perceived financial burden from cancer care were associated with higher barriers. These patients may need extra attention in terms of decisional support. Overall, patients with fewer personal resources (education, financial issues) report more attitudinal barriers and should be targeted for additional decisional support.

Effects of troponin T cardiomyopathy mutations on the calcium sensitivity of the regulated thin filament and the actomyosin cross-bridge kinetics of human β-cardiac myosin

Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) lead to significant cardiovascular morbidity and mortality worldwide. Mutations in the genes encoding the sarcomere, the force-generating unit in the cardiomyocyte, cause familial forms of both HCM and DCM. This study examines two HCM-causing (I79N, E163K) and two DCM-causing (R141W, R173W) mutations in the troponin T subunit of the troponin complex using human β-cardiac myosin. Unlike earlier reports using various myosin constructs, we found that none of these mutations affect the maximal sliding velocities or maximal Ca²⁺-activated ADP release rates involving the thin filament human β-cardiac myosin complex. Changes in Ca²⁺ sensitivity using the human myosin isoform do, however, mimic changes seen previously with non-human myosin isoforms. Transient kinetic measurements show that these mutations alter the kinetics of Ca²⁺ induced conformational changes in the regulatory thin filament proteins. These changes in calcium sensitivity are independent of active, cycling human β-cardiac myosin.

Abstract P6-09-05: Women's perceptions of lymphedema risk management: Psychological factors do matter

Introduction: Lymphedema arising from breast cancer surgery and treatment is characterized by arm impairment, physical disfigurement, emotional distress and diminished quality of life. Given no specific lymphedema cure, early detection and risk management strategies are recommended. The American Cancer Society (ACS) identifies simple behavioral strategies to minimize lymphedema risk; however, little is known about women's adherence to these recommendations over time. Even less is known about how women perceive lymphedema risk and the psychological factors that promote long-term adherence. Guided by the Cognitive-Social Health Information Processing model we assessed adherence to risk management strategies and identified psychological factors associated with adherence.

Methods: Women (N = 103) diagnosed with primary breast cancer and scheduled for breast surgery initially completed the baseline questionnaire prior to surgery, and then received the ACS publication “Lymphedema: What Every Woman With Breast Cancer Should Know” as part of usual care. Follow-up questionnaires were completed by participants 6- and 12-months later. Baseline data collected included demographic and medical history variables, lymphedema-related knowledge and cognitive and affective factors (perceived risk, beliefs and expectancies, self-regulatory competencies, negative affect), and adherence to risk management strategies. Adherence was also assessed at 6- and 12-months. A mixed-model maximum-likelihood logistic regression was employed in data analyses.

Results: Adherence to risk minimization strategies increased over time (p &lt; .001) and varied with the specific strategy (p &lt; .001). Risk minimization strategies fell into three broad groupings: 1) High levels of consistent adherence across time - wearing loose clothing, avoiding tight jewelry, avoiding blood pressure readings and avoiding trauma to the arm; 2) Moderate levels of adherence and greater variability across time - avoiding cutting cuticles, extreme sun exposure, carrying heavy bags, and temperature extremes, and consulting with a doctor when symptoms appear; 3) Low level of adherence - wearing protective gloves and using an electric razor. Baseline knowledge was associated with adherence to all strategies. In addition, increased self-efficacy to enact the strategies (OR = 1.82, p = 0.0001), greater beliefs in one's self-regulatory ability to manage distress (OR = 1.25, p = 0.0017), and decreased risk-related negative affect (OR = 0.96, p = 0.03) were associated with increased adherence to the recommendations.

Conclusions: During the 12 months following breast cancer diagnosis, women demonstrated increased awareness of lymphedema risk management and adherence to the recommended strategies, although adherence to individual strategies varied. Psychological factors were associated with adherence to recommendations. Specifically, women with greater knowledge, self-efficacy to enact recommended strategies and ability to self-regulate negative emotions, and lower negative affect were more likely to be adherent. These findings suggest that for lymphedema education approaches to be maximally effective, they should incorporate psychological interventions designed to enhance self-efficacy and coping in women at risk to ensure long-term adherence.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-09-05.

The relationships among knowledge, self-efficacy, preparedness, decisional conflict, and decisions to participate in a cancer clinical trial

BACKGROUND

Cancer clinical trials (CCTs) are important tools in the development of improved cancer therapies; yet, participation is low. Key psychosocial barriers exist that appear to impact a patient's decision to participate. Little is known about the relationship among knowledge, self-efficacy, preparation, decisional conflict, and patient decisions to take part in CCTs.

OBJECTIVE

The purpose of this study was to determine if preparation for consideration of a CCT as a treatment option mediates the relationship between knowledge, self-efficacy, and decisional conflict. We also explored whether lower levels of decisional conflict are associated with greater likelihood of CCT enrollment.

METHOD

In a pre-post test intervention study, cancer patients (N = 105) were recruited before their initial consultation with a medical oncologist. A brief educational intervention was provided for all patients. Patient self-report survey responses assessed knowledge, self-efficacy, preparation for clinical trial participation, decisional conflict, and clinical trial participation.

RESULTS

Preparation was found to mediate the relationship between self-efficacy and decisional conflict (p = 0.003 for a test of the indirect mediational pathway for the decisional conflict total score). Preparation had a more limited role in mediating the effect of knowledge on decisional conflict. Further, preliminary evidence indicated that reduced decisional conflict was associated with increased clinical trial enrollment (p = 0.049).

CONCLUSIONS

When patients feel greater CCT self-efficacy and have more knowledge, they feel more prepared to make a CCT decision. Reduced decisional conflict, in turn, is associated with the decision to enroll in a clinical trial. Our results suggest that preparation for decision-making should be a target of future interventions to improve participation in CCTs.

Discovering mercury protein modifications in whole proteomes using natural isotope distributions observed in liquid chromatography-tandem mass spectrometry

The identification of peptides that result from post-translational modifications is critical for understanding normal pathways of cellular regulation as well as identifying damage from, or exposures to xenobiotics, i.e. the exposome. However, because of their low abundance in proteomes, effective detection of modified peptides by mass spectrometry (MS) typically requires enrichment to eliminate false identifications. We present a new method for confidently identifying peptides with mercury (Hg)-containing adducts that is based on the influence of mercury's seven stable isotopes on peptide isotope distributions detected by high-resolution MS. Using a pure protein and E. coli cultures exposed to phenyl mercuric acetate, we show the pattern of peak heights in isotope distributions from primary MS single scans efficiently identified Hg adducts in data from chromatographic separation coupled with tandem mass spectrometry with sensitivity and specificity greater than 90%. Isotope distributions are independent of peptide identifications based on peptide fragmentation (e.g. by SEQUEST), so both methods can be combined to eliminate false positives. Summing peptide isotope distributions across multiple scans improved specificity to 99.4% and sensitivity above 95%, affording identification of an unexpected Hg modification. We also illustrate the theoretical applicability of the method for detection of several less common elements including the essential element, selenium, as selenocysteine in peptides.

High-flow nasal cannula and extubation success in the premature infant: a comparison of two modalities

OBJECTIVE

To compare the effectiveness of Fisher and Paykel (FP) and Vapotherm (VT) high-flow nasal cannula (HFNC) in preventing reintubation either within 72 h or <7 days after extubation of premature infants. The primary outcome was the rate of extubation failure defined as reintubation within 72 h. Secondary outcomes included reintubation after ≤7 days.

STUDY DESIGN

This was a prospective, randomized pilot study comparing the extubation success of 40 infants born between 26 and 29 weeks of gestation.

RESULT

The rate of extubation failure at 72 h was 18% for FP and 9% for VT. The failure rate ≤7 days after extubation was 30% for FP and 27% for VT. None of these differences were statistically significant.

CONCLUSION

There was no difference between FP and VT in the extubation success of infants born between 26 and 29 weeks.

Direct measurement of mercury(II) removal from organomercurial lyase (MerB) by tryptophan fluorescence: NmerA domain of coevolved γ-proteobacterial mercuric ion reductase (MerA) is more efficient than MerA catalytic core or glutathione

Aerobic and facultative bacteria and archaea harboring mer loci exhibit resistance to the toxic effects of Hg(II) and organomercurials [RHg(I)]. In broad spectrum resistance, RHg(I) is converted to less toxic Hg(0) in the cytosol by the sequential action of organomercurial lyase (MerB: RHg(I) → RH + Hg(II)) and mercuric ion reductase (MerA: Hg(II) → Hg(0)) enzymes, requiring transfer of Hg(II) from MerB to MerA. Although previous studies with γ-proteobacterial versions of MerA and a nonphysiological Hg(II)-DTT-MerB complex qualitatively support a pathway for direct transfer between proteins, assessment of the relative efficiencies of Hg(II) transfer to the two different dicysteine motifs in γ-proteobacterial MerA and to competing cellular thiol is lacking. Here we show the intrinsic tryptophan fluorescence of γ-proteobacterial MerB is sensitive to Hg(II) binding and use this to probe the kinetics of Hg(II) removal from MerB by the N-terminal domain (NmerA) and catalytic core C-terminal cysteine pairs of its coevolved MerA and by glutathione (GSH), the major competing cellular thiol in γ-proteobacteria. At physiologically relevant concentrations, reaction with a 10-fold excess of NmerA over HgMerB removes ≥92% Hg(II), while similar extents of reaction require more than 1000-fold excess of GSH. Kinetically, the apparent second-order rate constant for Hg(II) transfer from MerB to NmerA, at (2.3 ± 0.1) × 10(4) M(-1) s(-1), is ∼100-fold greater than that for GSH ((1.2 ± 0.2) × 10(2) M(-1) s(-1)) or the MerA catalytic core (1.2 × 10(2) M(-1) s(-1)), establishing transfer to the metallochaperone-like NmerA domain as the kinetically favored pathway in this coevolved system.

Chromosomes from testicular preparations of lepidoptera

Typical elongate, beaded chromosomes have been observed in squash preparations of testicular tissue of the butterfly Speyeria aphrodite (Fabricius), the first demonstration of relatively uncondensed chromosomes in the Lepidoptera.

Structure and conformational dynamics of the metalloregulator MerR upon binding of Hg(II)

The bacterial metalloregulator MerR is the index case of an eponymous family of regulatory proteins, which controls the transcription of a set of genes (the mer operon) conferring mercury resistance in many bacteria. Homodimeric MerR represses transcription in the absence of mercury and activates transcription upon Hg(II) binding. Here, the average structures of the apo and Hg(II)-bound forms of MerR in aqueous solution are examined using small-angle X-ray scattering, indicating an extended conformation of the metal-bound protein and revealing the existence of a novel compact conformation in the absence of Hg(II). Molecular dynamics (MD) simulations are performed to characterize the conformational dynamics of the Hg(II)-bound form. In both small-angle X-ray scattering and MD, the average torsional angle between DNA-binding domains is approximately 65 degrees. Furthermore, in MD, interdomain motions on a timescale of approximately 10 ns involving large-amplitude (approximately 20 A) domain opening-and-closing, coupled to approximately 40 degrees variations of interdomain torsional angle, are revealed. This correlated domain motion may propagate allosteric changes from the metal-binding site to the DNA-binding site while maintaining DNA contacts required to initiate DNA underwinding.

Literacy assessment of family health history tools for public health prevention

OBJECTIVES

This study aimed to systematically identify and evaluate the readability and document complexity of currently available family history tools for the general public.

METHODS

Three steps were undertaken to identify family history tools for evaluation: (a) Internet searches, (b) expert consultation, and (c) literature searches. Tools identified were assessed for readability using the Simple Measure of Gobbledygook (SMOG) readability formula. The complexity of documents (i.e., forms collecting family history information) was assessed using the PMOSE/IKIRSCH document readability formula.

RESULTS

A total of 78 tools were identified, 47 of which met the criteria for inclusion. SMOG reading grade levels for multimedia-based tools ranged from 10.1 to 18.3, with an average score of 13.6. For print-based tools, SMOG ranged from 8.7 to 14.1, with an average score of 12.0. Document complexity ranged from very low complexity (level 1 proficiency) to high complexity (level 4 proficiency).

CONCLUSION

The majority of tools are written at a reading grade level that is beyond the 8th grade average reading level in the United States. The lack of family history tools that are easy to read or use may compromise their potential effectiveness in identifying individuals at increased risk for chronic diseases in the general population.

Psychometric validation of a subjective well-being measure for people with spinal cord injuries

PURPOSE

The researchers examined the factorial validity and the concurrent validity of the Sense of Well-Being Inventory (SWBI) based on a sample of Canadians with spinal cord injuries (SCI) in the community.

METHOD

One hundred thirty-two participants were recruited from the Alberta, Saskatchewan, Nova Scotia, and Manitoba chapters of the Canadian Paraplegic Association. Mean age of participants was 45.82 years (SD=15.67), and 77% were men. The participants were asked to complete a research packet containing a demographic questionnaire, the SWBI, and the brief version of the World Health Organization Quality of Life questionnaire (WHOQOL-BREF).

RESULTS

Factor analysis yield four factors (Psychological Well-Being, Financial Well-Being, Social and Family Well-Being, and Physical Well-Being) similar to the original SWBI. In addition, the SWBI factors in the present study correlated moderately well with the corresponding factors in the WHOQOL-BREF and with demographic variables appropriate to the respective subscale.

CONCLUSIONS

The factorial validity and the concurrent validity of the SWBI were generally supported. The SWBI, as a subjective well-being measure developed specifically to relate to disability and rehabilitation, appears useful for use with people with SCI in the community.