Investigation of two new putative pheromone components of the invasive Australian redback spider,Latrodectus hasseltii,with potential applications for control

The Australian redback spider, Latrodectus hasseltii preys on at least 10 endemic species in New Zealand, highlighting a need for control. Male redbacks are attracted to virgin females by an airborne pheromone. The aim of this study was to analyse the response of male redback spiders to two volatile chemicals found on the silk of virgin but not mated females, to determine whether these compounds constitute components of the airborne pheromone. Mature male redback spiders were placed in an olfactometer where they had a choice of two stimuli. We compared their response to paired combinations of a control, virgin silk, butyric acid and isovaleric acid. Male redbacks responded equally strongly to butyric acid and virgin silk, in terms of time spent near the stimulus. The identification of butyric acid as a component of the airborne sex pheromone of L. hasseltii provides the groundwork for developing a pheromone-based control.     

Advancing the use of morphometric data for estimating and managing common bottlenose dolphin (Tursiops truncatus) mass

Knowledge of a dolphin's body mass is central to establishing body condition, comparing across individuals, and designing successful management programs. In the present study, sex‐specific prediction equations for estimating body mass were generated from morphometrics (i.e., length and girth) and ages of bottlenose dolphins residing under professionally managed care. Measurements of wild dolphins in Sarasota Bay, Florida, were used to generate sex‐specific body mass reference ranges. Gompertz growth models were fitted to length measurements and age to compare growth across populations. From the regression analyses, the body mass of managed females (R² = 0.937), managed males (R² = 0.953), wild females (R² = 0.979), and wild males (R² = 0.972) were predicted with high levels of accuracy. Managed adults had similar or longer asymptotic lengths compared to their wild conspecifics. To apply this information, ZooMorphTrak, a mobile software application, was developed to provide a new resource for management. The “Approximate” feature was designed to approximate body mass based on user inputs of individual morphometrics. The “Management” feature compared a managed dolphin's known body mass with respect to body mass reference ranges generated from wild dolphins. ZooMorphTrak, developed by the Chicago Zoological Society, is available for download at http://itunes.apple.com .     

Relationship Between Carbon Mobilization and Root Growth Measured by Carbon-11 Tracer in Arabidopsis Starch Mutants

Journal of Plant Growth Regulation - Experiments designed to quantify the physiological and metabolic status of Arabidopsis thaliana seedlings across their photoperiod used wild-type (Col-0) and...     

Prevention of violence against women and girls: A cost-effectiveness study across 6 low- and middle-income countries

BackgroundViolence against women and girls (VAWG) is a human rights violation with social, economic, and health consequences for survivors, perpetrators, and society. Robust evidence on economic, social, and health impact, plus the cost of delivery of VAWG prevention, is critical to making the case for investment, particularly in low- and middle-income countries (LMICs) where health sector resources are highly constrained. We report on the costs and health impact of VAWG prevention in 6 countries.Methods and findingsWe conducted a trial-based cost-effectiveness analysis of VAWG prevention interventions using primary data from 5 randomised controlled trials (RCTs) in sub-Saharan Africa and 1 in South Asia. We evaluated 2 school-based interventions aimed at adolescents (11 to 14 years old) and 2 workshop-based (small group or one to one) interventions, 1 community-based intervention, and 1 combined small group and community-based programme all aimed at adult men and women (18+ years old). All interventions were delivered between 2015 and 2018 and were compared to a do-nothing scenario, except for one of the school-based interventions (government-mandated programme) and for the combined intervention (access to financial services in small groups). We computed the health burden from VAWG with disability-adjusted life year (DALY). We estimated per capita DALYs averted using statistical models that reflect each trial’s design and any baseline imbalances. We report cost-effectiveness as cost per DALY averted and characterise uncertainty in the estimates with probabilistic sensitivity analysis (PSA) and cost-effectiveness acceptability curves (CEACs), which show the probability of cost-effectiveness at different thresholds. We report a subgroup analysis of the small group component of the combined intervention and no other subgroup analysis. We also report an impact inventory to illustrate interventions’ socioeconomic impact beyond health. We use a 3% discount rate for investment costs and a 1-year time horizon, assuming no effects post the intervention period. From a health sector perspective, the cost per DALY averted varies between US$222 (2018), for an established gender attitudes and harmful social norms change community-based intervention in Ghana, to US$17,548 (2018) for a livelihoods intervention in South Africa. Taking a societal perspective and including wider economic impact improves the cost-effectiveness of some interventions but reduces others. For example, interventions with positive economic impacts, often those with explicit economic goals, offset implementation costs and achieve more favourable cost-effectiveness ratios. Results are robust to sensitivity analyses. Our DALYs include a subset of the health consequences of VAWG exposure; we assume no mortality impact from any of the health consequences included in the DALYs calculations. In both cases, we may be underestimating overall health impact. We also do not report on participants’ health costs.ConclusionsWe demonstrate that investment in established community-based VAWG prevention interventions can improve population health in LMICs, even within highly constrained health budgets. However, several VAWG prevention interventions require further modification to achieve affordability and cost-effectiveness at scale. Broadening the range of social, health, and economic outcomes captured in future cost-effectiveness assessments remains critical to justifying the investment urgently required to prevent VAWG globally.

In a cost-effectiveness study, Dr. Giulia Ferrari and colleagues examine the costs and health impact of prevention of violence against women and girls in six low- and middle-income countries.     

Utility of the trnH–psbA Intergenic Spacer Region and Its Combinations as Plant DNA Barcodes: A Meta-Analysis

Background

The trnH–psbA intergenic spacer region has been used in many DNA barcoding studies. However, a comprehensive evaluation with rigorous sequence preprocessing and statistical testing on the utility of trnH–psbA and its combinations as DNA barcodes is lacking.

Methodology/Principal Findings

Sequences were searched from GenBank for a meta-analysis on the usefulness of trnH–psbA and its combinations as DNA barcodes. After preprocessing, we constructed full and matching data sets that contained 17 983 trnH–psbA sequences and 2190 sets of trnH–psbA, matK, rbcL, and ITS2 sequences from the same sample, repectively. These datasets were used to analyze the ability of trnH–psbA and its combinations to discriminate species by the BLAST and BLAST+P methods. The Fisher''s exact test was used to evaluate the significance of performance differences. For the full data set, the identification success rates of trnH–psbA exceeded 70% in 18 families and 12 genera, respectively. For the matching data set, the identification rates of trnH–psbA were significantly higher than those of the other loci in two families and four genera. Similarly, the identification rates of trnH–psbA+ITS2 were significantly higher than those of matK+rbcL in 18 families and 21 genera.

Conclusion/Significane

This study provides valuable information on the higher utility of trnH–psbA and its combinations. We found that trnH–psbA+ITS2 combination performs better or equally well compared with other combinations in most taxonomic groups investigated. This information will guide the optimal usage of trnH–psbA and its combinations for species identification.     

The role of apolipoprotein A-I helix 10 in apolipoprotein-mediated cholesterol efflux via the ATP-binding cassette transporter ABCA1

Recent studies of Tangier disease have shown that the ATP-binding cassette transporter A1 (ABCA1)/apolipoprotein A-I (apoA-I) interaction is critical for high density lipoprotein particle formation, apoA-I integrity, and proper reverse cholesterol transport. However, the specifics of this interaction are unknown. It has been suggested that amphipathic helices of apoA-I bind to a lipid domain created by the ABCA1 transporter. Alternatively, apoA-I may bind directly to ABCA1 itself. To better understand this interaction, we created several truncation mutants of apoA-I and then followed up with more specific point mutants and helix translocation mutants to identify and characterize the locations of apoA-I required for ABCA1-mediated cholesterol efflux. We found that deletion of residues 221-243 (helix 10) abolished ABCA1-mediated cholesterol efflux from cultured RAW mouse macrophages treated with 8-bromo-cAMP. Point mutations in helix 10 that affected the helical charge distribution reduced ABCA1-mediated cholesterol efflux versus the wild type. We noted a strong positive correlation between cholesterol efflux and the lipid binding characteristics of apoA-I when mutations were made in helix 10. However, there was no such correlation for helix translocations in other areas of the protein as long as helix 10 remained intact at the C terminus. From these observations, we propose an alternative model for apolipoprotein-mediated efflux.     

Bacterial expression and characterization of mature apolipoprotein A-I

Plasma levels of apolipoprotein A-I (apoA-I) are correlated with reduced incidence of heart disease due to the critical role of this protein in reverse cholesterol transport. Because of its diversity of function and poorly understood structure, much research has sought to understand how the structure of apoA-I facilitates its function. A popular approach has been the use of site-directed mutagenesis followed by structural and functional studies. There are a wide variety of expression systems available to produce these mutant proteins including eukaryotic cell lines and prokaryotic cells such as Escherichia coli. Expression in a bacterial system is generally favorable because it can produce large amounts of pure protein quickly and economically through the use of affinity tags on the expressed protein. Unfortunately, many of these systems are not ideal for the production of apolipoproteins because, in many cases, the proteolytic digestion required to remove the affinity tag also cleaves the target protein. Here we describe a method that produces large amounts of recombinant protein that is easily purified using a histidine (His) affinity tag that is cleaved with IgA protease from Neisseria gonorrhoeae. This enzyme does not cleave the wild type apoA-I sequence, leaving intact, mature apoA-I (containing a Thr-Pro- on the N-terminus). We show that this recombinant protein is similar to wild type protein in structure and function using circular dichroism analysis, lipid clearance assays, recombinant particle formation and cholesterol efflux assays. This system is particularly useful for the bacterial production of apolipoproteins because of the extreme specificity of IgA protease for its target cleavage site.     

Postactivation potentiation response in athletic and recreationally trained individuals

To determine if training status directly impacted the response to postactivation potentiation, athletes in sports requiring explosive strength (ATH; n = 7) were compared to recreationally trained (RT; n = 17) individuals. Over the course of 4 sessions, subjects performed rebound and concentric-only jump squats with 30%, 50%, and 70% 1 RM loads. Jump squats were performed 5 minutes and 18.5 minutes following control or heavy load warm-ups. Heavy load warm-up consisted of 5 sets of 1 repetition at 90% 1 RM back squat. Jump squat performance was assessed with a force platform and position transducer. Heavy load warm-up did not have an effect on the subjects as a single sample. However, when percent potentiation was compared between ATH and RT groups, force and power parameters were significantly greater for ATH (p < 0.05). Postactivation potentiation may be a viable method of acutely enhancing explosive strength performance in athletic but not recreationally trained individuals. Reference Data: Chiu, L.Z.F., A.C. Fry, L.W. Weiss, B.K. Schilling, L.E. Brown, and S.L. Smith. Postactivation potentiation response in athletic and recreationally trained individuals.     

Genetic diversity in Cypripedium calceolus (Orchidaceae) with a focus on north-western Europe, as revealed by plastid DNA length polymorphisms

Background and Aims

Cypripedium calceolus, although widespread in Eurasia, is rare in many countries in which it occurs. Population genetics studies with nuclear DNA markers on this species have been hampered by its large nuclear genome size. Plastid DNA markers are used here to gain an understanding of variation within and between populations and of biogeographical patterns.

Methods

Thirteen length-variable regions (microsatellites and insertions/deletions) were identified in non-coding plastid DNA. These and a previously identified complex microsatellite in the trnL-trnF intergenic spacer were used to identify plastid DNA haplotypes for European samples, with sampling focused on England, Denmark and Sweden.

Key Results

The 13 additional length-variable regions identified were two homopolymer (polyA) repeats in the rps16 intron and a homopolymer (polyA) repeat and ten indels in the accD-psa1 intergenic spacer. In accD-psa1, most of these were in an extremely AT-rich region, and it was not possible to design primers in the flanking regions; therefore, the whole intergenic spacer was sequenced. Together, these new regions and the trnL-trnF complex microsatellite allowed 23 haplotypes to be characterized. Many were found in only one or a few samples (probably due to low sampling density), but some commoner haplotypes were widespread. Most of the genetic variation was found within rather than between populations (83 vs. 18%, respectively). Two haplotypes occurred from the Spanish Pyrenees to Sweden.

Conclusions

Plastid DNA data can be used to gain an understanding of patterns of genetic variation and seed-mediated gene flow in orchids. Although these data are less information-rich than those for nuclear DNA, they present a useful option for studying species with large genomes. Here they support the hypothesis of long-distance seed dispersal often proposed for orchids.Key words: Biogeography, Cypripedium calceolus, genome size, plastid microsatellites, population genetics, seed dispersal     

Ala Scanning of the Inhibitory Region of Cardiac Troponin I

In skeletal and cardiac muscles, troponin (Tn), which resides on the thin filament, senses a change in intracellular Ca²⁺ concentration. Tn is composed of TnC, TnI, and TnT. Ca²⁺ binding to the regulatory domain of TnC removes the inhibitory effect by TnI on the contraction. The inhibitory region of cardiac TnI spans from residue 138 to 149. Upon Ca²⁺ activation, the inhibitory region is believed to be released from actin, thus triggering actin-activation of myosin ATPase. In this study, we created a series of Ala-substitution mutants of cTnI to delineate the functional contribution of each amino acid in the inhibitory region to myofilament regulation. We found that most of the point mutations in the inhibitory region reduced the ATPase activity in the presence of Ca²⁺, which suggests the same region also acts as an activator of the ATPase. The thin filaments can also be activated by strong myosin head (S1)-actin interactions. The binding of N-ethylmaleimide-treated myosin subfragment 1 (NEM-S1) to actin filaments mimics such strong interactions. Interestingly, in the absence of Ca²⁺ NEM-S1-induced activation of S1 ATPase was significantly less with the thin filaments containing TnI(T144A) than that with the wild-type TnI. However, in the presence of Ca²⁺, there was little difference in the activation of ATPase activity between these preparations.Striated muscle thin filaments exist in equilibrium among multiple states. Ca²⁺ binding to the regulatory domain of troponin C (TnC)² along the thin filaments and strong cross-bridge interactions with thick filaments are thought to shift the equilibrium. Ca²⁺ binds to the regulatory domain of TnC, which regulates the interaction of troponin I (TnI) with actin-tropomyosin (Tm) and TnC (1–3). In the thin filaments, the inhibitory region of TnI (residues 104–115 of rabbit fast skeletal TnI (fsTnI) or 138–149 of mouse cardiac TnI (cTnI)) undergoes a structural transition depending on the Ca²⁺ state of TnC (4, 5). In the absence of Ca²⁺ at the regulatory site(s) of TnC, the inhibitory region interacts with actin to prevent activation of myosin ATPase activity. When Ca²⁺ binds to the regulatory site(s) of TnC, the switch region of TnI, which is located at the C terminus of the inhibitory region, interacts with the newly exposed hydrophobic patch of the N-terminal regulatory domain of TnC (6–8). This interaction causes the removal of the inhibitory region and the second actin-Tm binding region of TnI from the actin surface and allows actin to interact with myosin. In the presence of Ca²⁺ at the regulatory sites of TnC, the inhibitory region and the central helical region of TnC are mutually stabilized, according to the recent x-ray crystal structure of the core domain of the fsTn complex (9). The sequence variations in the N-terminal and the C-terminal regions of TnT, another component of the Tn complex, are known to alter the Ca²⁺ sensitivity of myofilament activity (10, 11). In addition, TnT is involved in the Ca²⁺-dependent interaction of the Tn complex with actin-Tm (12). However, the molecular mechanism whereby TnT participates in the Ca²⁺ regulation has not been established.There is evidence supporting the idea that each amino acid residue in the inhibitory region of TnI contributes differently and to a different degree to myofilament activities. One example is genetic mutations and phosphorylation of amino acid residues in the inhibitory region of cardiac TnI that cause the modification of myofilament activities. In hypertrophic or restrictive cardiomyopathy-linked mutations found in the inhibitory region, such as R142Q, L145Q, and R146G/Q/W mutations (mouse cTnI sequence number), induce Ca²⁺ sensitization of myofilament activities and an increase in ATPase/tension at low [Ca²⁺] (13, 14). Recently we reported that thin filaments reconstituted with R146G or R146W mutant cTnI bind Ca²⁺ tighter than those with cTnI(wt) (15). The Ca²⁺ sensitization may occur as a result of the destabilization of the off-state of the thin filaments due to the mutation introduced into the actin-Tm-interacting residue, i.e. Arg-146, of cTnI. On the other hand, Thr-144 is phosphorylated by protein kinase C (PKC) specifically, although the consequence of the PKC-dependent phosphorylation of Thr-144 has not yet been clearly defined. Pseudophosphorylation of Thr-144 was shown to cause Ca²⁺ desensitization in in vitro motility assays (16), whereas there is a report that indicates phosphorylation of Thr-144 sensitizes skinned cardiomyocytes to Ca²⁺ (17). Furthermore, Tachampa et al. reported that Thr-144 of cTnI is important for length-dependent activation of skinned cardiac muscle (18). Thus in each case presented above, a specific change in a single amino acid in the inhibitory region of TnI induced different and divergent effects on myofilament activities.Our aim of this study is to assess the functional contributions of the individual amino acid residues in the inhibitory region to the regulatory function. To assess the functional roles of the individual amino acid residues systematically, we used Ala scanning (19, 20). Ala substitution deletes all the interactions made by atoms beyond β-C yet does not alter the peptide backbone conformation, unless it is applied to Gly or Pro. Ala is one of the most abundant amino acids and is found in both buried and exposed positions. We found that almost the entire minimum inhibitory region of cTnI we investigated (Fig. 1) is important for both the inhibition and activation. Our data also indicate that the C-terminal part of the inhibitory region destabilizes the active state of the thin filaments. We also found that Thr-144 is involved in NEM-S1-dependent activation of ATPase activity in the absence of Ca²⁺.Open in a separate windowFIGURE 1.Inhibitory region of TnI. A, sequence comparison of the minimum inhibitory region from various vertebrates. The amino acid residues that are different from fsTnI are colored green in cardiac sequences. Note the amino acid sequence of the inhibitory region is highly conserved. Also the amino acid sequences of the minimum inhibitory region of the mutants we investigated in this study are shown. B, crystal structure of the inhibitory region and its surrounding region in chicken fsTn complex in the Ca²⁺-bound form (PDB: 1YTZ). TnC, pink; TnT, light blue; TnI, gray. The segment, corresponding to residues 143–149 of mouse cTnI, is colored red.