An overview of the involvement of women in fisheries activities in Oceania

Role of women, Fisheries, Oceania,

Chimpanzees (Pan troglodytes) do not Develop Contingent Reciprocity in an Experimental Task

Chimpanzees provide help to unrelated individuals in a broad range of situations. The pattern of helping within pairs suggests that contingent reciprocity may have been an important mechanism in the evolution of altruism in chimpanzees. However, correlational analyses of the cumulative pattern of interactions over time do not demonstrate that helping is contingent upon previous acts of altruism, as required by the theory of reciprocal altruism. Experimental studies provide a controlled approach to examine the importance of contingency in helping interactions. In this study, we evaluated whether chimpanzees would be more likely to provide food to a social partner from their home group if their partner had previously provided food for them. The chimpanzees manipulated a barpull apparatus in which actors could deliver rewards either to themselves and their partners or only to themselves. Our findings indicate that the chimpanzees’ responses were not consistently influenced by the behavior of their partners in previous rounds. Only one of the 11 dyads that we tested demonstrated positive reciprocity. We conclude that contingent reciprocity does not spontaneously arise in experimental settings, despite the fact patterns of behavior in the field indicate that individuals cooperate preferentially with reciprocating partners

Chimpanzees Do Not Take Advantage of Very Low Cost Opportunities to Deliver Food to Unrelated Group Members

We conducted experiments on two populations of chimpanzees, Pan troglodytes, to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social groups. We compared the chimpanzees\u27 behaviour when they were paired with another chimpanzee and when they were alone. If chimpanzees are motivated to provide benefits to others, they are expected to consistently deliver rewards to others and to distinguish between the partner-present and partner-absent conditions. Results from both experiments indicate that our subjects were largely indifferent to the benefits they could provide to others. They were less likely to provide rewards to potential recipients as the experiment progressed, and all but one of the 18 subjects were as likely to deliver rewards to an empty enclosure as to an enclosure housing another chimpanzee. These results, in conjunction with similar results obtained in previous experiments, suggest that chimpanzees are not motivated by prosocial sentiments to provide food rewards to other group members. The Association for the Study of Animal Behaviour. Published by Elsevier Ltd

Investigation of the Proteolytic Functions of an Expanded Cercarial Elastase Gene Family in Schistosoma mansoni

Schistosome parasites are a major cause of disease in the developing world. The larval stage of the parasite transitions between an intermediate snail host and a definitive human host in a dramatic fashion, burrowing out of the snail and subsequently penetrating human skin. This process is facilitated by secreted proteases. In Schistosoma mansoni, cercarial elastase is the predominant secreted protease and essential for host skin invasion. Genomic analysis reveals a greatly expanded cercarial elastase gene family in S. mansoni. Despite sequence divergence, SmCE isoforms show similar expression profiles throughout the S. mansoni life cycle and have largely similar substrate specificities, suggesting that the majority of protease isoforms are functionally redundant and therefore their expansion is an example of gene dosage. However, activity-based profiling also indicates that a subset of SmCE isoforms are activated prior to the parasite's exit from its intermediate snail host, suggesting that the protease may also have a role in this process

Exercise training comprising of single 20-s cycle sprints does not provide a sufficient stimulus for improving maximal aerobic capacity in sedentary individuals

Purpose: Sprint interval training (SIT) provides a potent stimulus for improving maximal aerobic capacity ([Formula: see text]), which is among the strongest markers for future cardiovascular health and premature mortality. Cycling-based SIT protocols involving six or more 'all-out' 30-s Wingate sprints per training session improve [Formula: see text], but we have recently demonstrated that similar improvements in [Formula: see text] can be achieved with as few as two 20-s sprints. This suggests that the volume of sprint exercise has limited influence on subsequent training adaptations. Therefore, the aim of the present study was to examine whether a single 20-s cycle sprint per training session can provide a sufficient stimulus for improving [Formula: see text]. Methods: Thirty sedentary or recreationally active participants (10 men/20 women; mean ± SD age: 24 ± 6 years, BMI: 22.6 ± 4.0 kg m(-2), [Formula: see text]: 33 ± 7 mL kg(-1) min(-1)) were randomised to a training group or a no-intervention control group. Training involved three exercise sessions per week for 4 weeks, consisting of a single 20-s Wingate sprint (no warm-up or cool-down). [Formula: see text] was determined prior to training and 3 days following the final training session. Results: Mean [Formula: see text] did not significantly change in the training group (2.15 ± 0.62 vs. 2.22 ± 0.64 L min(-1)) or the control group (2.07 ± 0.69 vs. 2.08 ± 0.68 L min(-1); effect of time: P = 0.17; group × time interaction effect: P = 0.26). Conclusion: Although we have previously demonstrated that regularly performing two repeated 20-s 'all-out' cycle sprints provides a sufficient training stimulus for a robust increase in [Formula: see text], our present study suggests that this is not the case when training sessions are limited to a single sprint

DNA damage induces reactive oxygen species generation through the H2AX-Nox1/Rac1 pathway

The DNA damage response (DDR) cascade and ROS (reactive oxygen species) signaling are both involved in the induction of cell death after DNA damage, but a mechanistic link between these two pathways has not been clearly elucidated. This study demonstrates that ROS induction after treatment of cells with neocarzinostatin (NCS), an ionizing radiation mimetic, is at least partly mediated by increasing histone H2AX. Increased levels of ROS and cell death induced by H2AX overexpression alone or DNA damage leading to H2AX accumulation are reduced by treating cells with the antioxidant N-Acetyl-L-Cysteine (NAC), the NADP(H) oxidase (Nox) inhibitor DPI, expression of Rac1N17, and knockdown of Nox1, but not Nox4, indicating that induction of ROS by H2AX is mediated through Nox1 and Rac1 GTPase. H2AX increases Nox1 activity partly by reducing the interaction between a Nox1 activator NOXA1 and its inhibitor 14-3-3zeta. These results point to a novel role of histone H2AX that regulates Nox1-mediated ROS generation after DNA damage

Role of cellular senescence and NOX4-mediated oxidative stress in systemic sclerosis pathogenesis.

Systemic sclerosis (SSc) is a systemic autoimmune disease characterized by progressive fibrosis of skin and numerous internal organs and a severe fibroproliferative vasculopathy resulting frequently in severe disability and high mortality. Although the etiology of SSc is unknown and the detailed mechanisms responsible for the fibrotic process have not been fully elucidated, one important observation from a large US population study was the demonstration of a late onset of SSc with a peak incidence between 45 and 54 years of age in African-American females and between 65 and 74 years of age in white females. Although it is not appropriate to consider SSc as a disease of aging, the possibility that senescence changes in the cellular elements involved in its pathogenesis may play a role has not been thoroughly examined. The process of cellular senescence is extremely complex, and the mechanisms, molecular events, and signaling pathways involved have not been fully elucidated; however, there is strong evidence to support the concept that oxidative stress caused by the excessive generation of reactive oxygen species may be one important mechanism involved. On the other hand, numerous studies have implicated oxidative stress in SSc pathogenesis, thus, suggesting a plausible mechanism in which excessive oxidative stress induces cellular senescence and that the molecular events associated with this complex process play an important role in the fibrotic and fibroproliferative vasculopathy characteristic of SSc. Here, recent studies examining the role of cellular senescence and of oxidative stress in SSc pathogenesis will be reviewed

A Model for Damage Load and Its Implications for the Evolution of Bacterial Aging

Deleterious mutations appearing in a population increase in frequency until stopped by natural selection. The ensuing equilibrium creates a stable frequency of deleterious mutations or the mutational load. Here I develop the comparable concept of a damage load, which is caused by harmful non-heritable changes to the phenotype. A damage load also ensues when the increase of damage is opposed by selection. The presence of a damage load favors the evolution of asymmetrical transmission of damage by a mother to her daughters. The asymmetry is beneficial because it increases fitness variance, but it also leads to aging or senescence. A mathematical model based on microbes reveals that a cell lineage dividing symmetrically is immortal if lifetime damage rates do not exceed a threshold. The evolution of asymmetry allows the lineage to persist above the threshold, but the lineage becomes mortal. In microbes with low genomic mutation rates, it is likely that the damage load is much greater than the mutational load. In metazoans with higher genomic mutation rates, the damage and the mutational load could be of the same magnitude. A fit of the model to experimental data shows that Escherichia coli cells experience a damage rate that is below the threshold and are immortal under the conditions examined. The model estimates the asymmetry level of E. coli to be low but sufficient for persisting at higher damage rates. The model also predicts that increasing asymmetry results in diminishing fitness returns, which may explain why the bacterium has not evolved higher asymmetry

Field Measurements of Terrestrial and Martian Dust Devils

Surface-based measurements of terrestrial and martian dust devils/convective vortices provided from mobile and stationary platforms are discussed. Imaging of terrestrial dust devils has quantified their rotational and vertical wind speeds, translation speeds, dimensions, dust load, and frequency of occurrence. Imaging of martian dust devils has provided translation speeds and constraints on dimensions, but only limited constraints on vertical motion within a vortex. The longer mission durations on Mars afforded by long operating robotic landers and rovers have provided statistical quantification of vortex occurrence (time-of-sol, and recently seasonal) that has until recently not been a primary outcome of more temporally limited terrestrial dust devil measurement campaigns. Terrestrial measurement campaigns have included a more extensive range of measured vortex parameters (pressure, wind, morphology, etc.) than have martian opportunities, with electric field and direct measure of dust abundance not yet obtained on Mars. No martian robotic mission has yet provided contemporaneous high frequency wind and pressure measurements. Comparison of measured terrestrial and martian dust devil characteristics suggests that martian dust devils are larger and possess faster maximum rotational wind speeds, that the absolute magnitude of the pressure deficit within a terrestrial dust devil is an order of magnitude greater than a martian dust devil, and that the time-of-day variation in vortex frequency is similar. Recent terrestrial investigations have demonstrated the presence of diagnostic dust devil signals within seismic and infrasound measurements; an upcoming Mars robotic mission will obtain similar measurement types