Gender Differences in Emotional Responses to Cooperative and Competitive Game Play

Previous research indicates that males prefer competition over cooperation, and it is sometimes suggested that females show the opposite behavioral preference. In the present article, we investigate the emotions behind the preferences: Do males exhibit more positive emotions during competitive than cooperative activities, and do females show the opposite pattern? We conducted two experiments where we assessed the emotional responses of same-gender dyads (in total 130 participants, 50 female) during intrinsically motivating competitive and cooperative digital game play using facial electromyography (EMG), skin conductance, heart rate measures, and self-reported emotional experiences. We found higher positive emotional responses (as indexed by both physiological measures and self-reports) during competitive than cooperative play for males, but no differences for females. In addition, we found no differences in negative emotions, and heart rate, skin conductance, and self-reports yielded contradictory evidence for arousal. These results support the hypothesis that males not only prefer competitive over cooperative play, but they also exhibit more positive emotional responses during them. In contrast, the results suggest that the emotional experiences of females do not differ between cooperation and competition, which implies that less competitiveness does not mean more cooperativeness. Our results pertain to intrinsically motivated game play, but might be relevant also for other kinds of activities.     

Ventilatory Chemosensory Drive Is Blunted in the mdx Mouse Model of Duchenne Muscular Dystrophy (DMD)

Duchenne Muscular Dystrophy (DMD) is caused by mutations in the DMD gene resulting in an absence of dystrophin in neurons and muscle. Respiratory failure is the most common cause of mortality and previous studies have largely concentrated on diaphragmatic muscle necrosis and respiratory failure component. Here, we investigated the integrity of respiratory control mechanisms in the mdx mouse model of DMD. Whole body plethysmograph in parallel with phrenic nerve activity recordings revealed a lower respiratory rate and minute ventilation during normoxia and a blunting of the hypoxic ventilatory reflex in response to mild levels of hypoxia together with a poor performance on a hypoxic stress test in mdx mice. Arterial blood gas analysis revealed low PaO₂ and pH and high PaCO₂ in mdx mice. To investigate chemosensory respiratory drive, we analyzed the carotid body by molecular and functional means. Dystrophin mRNA and protein was expressed in normal mice carotid bodies however, they are absent in mdx mice. Functional analysis revealed abnormalities in Dejours test and the early component of the hypercapnic ventilatory reflex in mdx mice. Together, these results demonstrate a malfunction in the peripheral chemosensory drive that would be predicted to contribute to the respiratory failure in mdx mice. These data suggest that investigating and monitoring peripheral chemosensory drive function may be useful for improving the management of DMD patients with respiratory failure.     

Proteolytically Inactive Insulin-Degrading Enzyme Inhibits Amyloid Formation Yielding Non-Neurotoxic Aβ Peptide Aggregates

Insulin-degrading enzyme (IDE) is a neutral Zn²⁺ peptidase that degrades short peptides based on substrate conformation, size and charge. Some of these substrates, including amyloid β (Aβ) are capable of self-assembling into cytotoxic oligomers. Based on IDE recognition mechanism and our previous report of the formation of a stable complex between IDE and intact Aβ in vitro and in vivo, we analyzed the possibility of a chaperone-like function of IDE. A proteolytically inactive recombinant IDE with Glu111 replaced by Gln (IDEQ) was used. IDEQ blocked the amyloidogenic pathway of Aβ yielding non-fibrillar structures as assessed by electron microscopy. Measurements of the kinetics of Aβ aggregation by light scattering showed that 1) IDEQ effect was promoted by ATP independent of its hydrolysis, 2) end products of Aβ-IDEQ co-incubation were incapable of “seeding” the assembly of monomeric Aβ and 3) IDEQ was ineffective in reversing Aβ aggregation. Moreover, Aβ aggregates formed in the presence of IDEQ were non-neurotoxic. IDEQ had no conformational effects upon insulin (a non-amyloidogenic protein under physiological conditions) and did not disturb insulin receptor activation in cultured cells. Our results suggest that IDE has a chaperone-like activity upon amyloid-forming peptides. It remains to be explored whether other highly conserved metallopeptidases have a dual protease-chaperone function to prevent the formation of toxic peptide oligomers from bacteria to mammals.     

In vitro efficacy of <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> sensu lato against unfed <Emphasis Type="Italic">Amblyomma parvum</Emphasis> (Acari: Ixodidae)

Amblyomma parvum Aragão (Acari: Ixodidae) is a tick species found with wide distribution in the Neotropical region. Even though it is a wildlife-related tick, it is also a frequent parasite of domestic animals, is aggressive to human beings and may harbor pathogenic microorganisms. Therefore, it is a target species for control on domestic animals, particularly those at the rural–wildlife interface. Herein, the efficacy of two isolates (E9 and IBCB 425) of an entomopathogenic fungus, Metarhizium anisopliae sensu lato, already evaluated for ticks that parasitize domestic animals, was tested against unfed A. parvum adults. Both isolates displayed high acaricidal efficacy after immersion in fungal conidial suspensions for 5 min. Isolate E9 killed all ticks by the 7th day post-treatment, and isolate IBCB 425 did so by the 11th day. Tick mortality of 80 and 90% was achieved as early as the 3rd and 4th days, respectively, with both treatments. Thus, if a commercial M. anisopliae s.l. acaricide against domestic animal ticks is developed, it would also be effective against A. parvum.     

Data-Driven Modeling of Intracellular Auxin Fluxes Indicates a Dominant Role of the ER in Controlling Nuclear Auxin Uptake

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Adult and nymphs of Microtriatoma trinidadensis (Lent, 1951) (Hemiptera: Reduviidae) caught from peridomestic environment in Bolivia.

This is the first report of adult and nymphs (20 nymphs of all stages and 4 adults) of Microtriatoma trinidadensis (Lent 1951) (Hemiptera: Reduviidae: Triatominae) collected in peridomestic environment, in the department of La Paz, Bolivia. These specimens were associated to Rhodnius stali Lent, Jurberg & Galv?o 1993. The exceptional finding of M. trinidadensis in peridomestic environment, illustrates the general tendency of triatominae to adapt to human dwellings and dependences.     

Gibberellic acid is selectively downregulated in response to aphid-induced gall formation

The fluid-feeding aphid Schlechtendalia chinensis (Bell) induces horned galls on its primary host, the Chinese Sumac (Rhus chinensis Mill). Horned galls are harvested for their high content of tannins, and used in a range of medical and chemical applications. Gall development is a complex and highly controlled physiological process, where the growing insect population manipulates the plant developmental programs that allow the transformation of plant tissue into a gall. In this study, we examine whether Schlechtendalia alters the balance of plant hormones in the host tree as a means to achieve gall formation. For this, we measured concentrations for a series of endogenous hormones, including indole-3-acetic acid (IAA), cytokinin (CTK), gibberellic acid (GA), abscisic acid (ABA), jasmonic acid (JA), salicylic acid (SA), and ethylene (ETH). Specifically, we conducted a time course (namely, 30, 85, 100, 115, 125, 140, 155, and 170 days from gall initiation) analysis, where we measured both gall and leaf samples representing different developmental stages that spanned an entire growing season. To correlate these hormone data with developmental parameters during gall growth, we determined gall volume, tannin content, and aphid population size for the same time points. Interestingly, tannin production rose steeply in the early stages of gall development, while the aphid population size grew little. After this single peak (day 100), tannin concentrations declined moderately and aphid population size increased from then on. This switch in population growth was accompanied by notable changes in plant hormone titers. In general, all hormones but GA were elevated in all sample types isolated from the host tree (gall, leaves near and distant from gall) when compared with samples from an uninfected tree. Most of the elevated hormones showed similar changes over time; however, GA appeared to display the opposite behavior in all samples, suggesting that GA is a key target for controlling gall growth. When tannin concentrations spiked, GA levels peaked as well, while the remaining plant hormones exhibited a decline at that time. Principle component analysis revealed distinct functional groups in our hormone cohort. This yielded three groups comprising (1) CTK, ABA, ETH, and JA, (2) IAA and SA, (3) GA. The fact that GA comprised its own group and exhibited a unique profile during gall development prompted us to examine whether exogenous GA would alter the rate of gall growth. Indeed, we found that ectopic GA significantly accelerated gall growth, and more strongly than all other hormones, consistent with the notion that controlling GA levels within the gall is crucial for stimulating gall development. We propose a model, whereby the host plant downregulates GA concentrations in an attempt to throttle gall growth, while the gall-inducing aphid population counters these attempts.