The Role of the Proteinase Inhibitor Ovorubin in Apple Snail Eggs Resembles Plant Embryo Defense against Predation

BACKGROUND: Fieldwork has thoroughly established that most eggs are intensely predated. Among the few exceptions are the aerial egg clutches from the aquatic snail Pomacea canaliculata which have virtually no predators. Its defenses are advertised by the pigmented ovorubin perivitellin providing a conspicuous reddish coloration. The nature of the defense however, was not clear, except for a screening for defenses that identified a neurotoxic perivitellin with lethal effect on rodents. Ovorubin is a proteinase inhibitor (PI) whose role to protect against pathogens was taken for granted, according to the prevailing assumption. Through biochemical, biophysical and feeding experiments we studied the proteinase inhibitor function of ovorubin in egg defenses. METHODOLOGY/PRINCIPAL FINDINGS: Mass spectrometry sequencing indicated ovorubin belongs to the Kunitz-type serine proteinase inhibitor family. It specifically binds trypsin as determined by small angle X-ray scattering (SAXS) and cross-linking studies but, in contrast to the classical assumption, it does not prevent bacterial growth. Ovorubin was found extremely resistant to in vitro gastrointestinal proteolysis. Moreover feeding studies showed that ovorubin ingestion diminishes growth rate in rats indicating that this highly stable PI is capable of surviving passage through the gastrointestinal tract in a biologically active form. CONCLUSIONS: To our knowledge, this is the first direct evidence of the interaction of an egg PI with a digestive protease of potential predators, limiting predator's ability to digest egg nutrients. This role has not been reported in the animal kingdom but it is similar to plant defenses against herbivory. Further, this would be the only defense model with no trade-offs between conspicuousness and noxiousness by encoding into the same molecule both the aposematic warning signal and an antinutritive/antidigestive defense. These defenses, combined with a neurotoxin and probably unpalatable factors would explain the near absence of predators, opening new perspectives in the study of the evolution and ecology of egg defensive strategies

Improving the efficacy of cognitive training for digital mental health interventions through avatar customization:crowdsourced quasi-experimental study

\u3cp\u3eBackground: The success of internet-based mental health interventions in practice—that is, in the wild—depends on the uptake and retention of the application and the user’s focused attention in the moment of use. Incorporating game-based motivational design into digital interventions delivered in the wild has been shown to increase uptake and retention in internet-based training; however, there are outstanding questions about the potential of game-based motivational strategies to increase engagement with a task in the moment of use and the effect on intervention efficacy. Objective: Designers of internet-based interventions need to know whether game-based motivational design strategies can increase in-the-moment engagement and thus improve digital interventions. The aim of this study was to investigate the effects of 1 motivational design strategy (avatar customization) in an example mental health intervention (computerized cognitive training for attention bias modification). Methods: We assigned 317 participants to either a customized avatar or an assigned avatar condition. After measuring state anxiety (State-Trait Anxiety Inventory), we randomly assigned half of the participants in each condition to either an attentional retraining condition (Attention Bias Modification Training) or a control condition. After training, participants were exposed to a negative mood induction using images with strong negative valance (International Affective Picture System), after which we measured state anxiety again. Results: Avatar customization decreased posttraining state anxiety when controlling for baseline state anxiety for those in the attentional retraining condition; however, those who did not train experienced decreased resilience to the negative mood induction (F \u3csub\u3e1,252\u3c/sub\u3e=6.86, P=.009, η \u3csub\u3ep\u3c/sub\u3e \u3csup\u3e2\u3c/sup\u3e=.027). This interaction effect suggests that customization increased task engagement with the intervention in the moment of use. Avatar customization also increased avatar identification (F \u3csub\u3e5,252\u3c/sub\u3e=12.46, P<.001, R \u3csup\u3e2\u3c/sup\u3e=.23), regardless of condition (F \u3csub\u3e1,252\u3c/sub\u3e=.79, P=.38). Avatar identification reduced anxiety after the negative mood induction for participants who underwent training but increased poststimulus anxiety for participants who did not undergo training, further suggesting that customization increases engagement in the task (F \u3csub\u3e1,252\u3c/sub\u3e=6.19, P=.01). The beneficial effect of avatar customization on training was driven by participants who were low in their basic satisfaction of relatedness (F \u3csub\u3e10,248\u3c/sub\u3e=18.5, P<.001, R \u3csup\u3e2\u3c/sup\u3e=.43), which is important because these are the participants who are most likely in need of digital interventions for mental health. Conclusions: Our results suggest that applying motivational design—specifically avatar customization—is a viable strategy to increase engagement and subsequently training efficacy in a computerized cognitive task. \u3c/p\u3

The potential of game-based digital biomarkers for modeling mental health

Background: Assessment for mental health is performed by experts using interview techniques, questionnaires, and test batteries and following standardized manuals; however, there would be myriad benefits if behavioral correlates could predict mental health and be used for population screening or prevalence estimations. A variety of digital sources of data (eg, online search data and social media posts) have been previously proposed as candidates for digital biomarkers in the context of mental health. Playing games on computers, gaming consoles, or mobile devices (ie, digital gaming) has become a leading leisure activity of choice and yields rich data from a variety of sources.\u3cbr/\u3e\u3cbr/\u3eObjective: In this paper, we argue that game-based data from commercial off-the-shelf games have the potential to be used as a digital biomarker to assess and model mental health and health decline. Although there is great potential in games developed specifically for mental health assessment (eg, Sea Hero Quest), we focus on data gathered “in-the-wild” from playing commercial off-the-shelf games designed primarily for entertainment.\u3cbr/\u3e\u3cbr/\u3eMethods: We argue that the activity traces left behind by natural interactions with digital games can be modeled using computational approaches for big data. To support our argument, we present an investigation of existing data sources, a categorization of observable traits from game data, and examples of potentially useful game-based digital biomarkers derived from activity traces.\u3cbr/\u3e\u3cbr/\u3eResults: Our investigation reveals different types of data that are generated from play and the sources from which these data can be accessed. Based on these insights, we describe five categories of digital biomarkers that can be derived from game-based data, including behavior, cognitive performance, motor performance, social behavior, and affect. For each type of biomarker, we describe the data type, the game-based sources from which it can be derived, its importance for mental health modeling, and any existing statistical associations with mental health that have been demonstrated in prior work. We end with a discussion on the limitations and potential of data from commercial off-the-shelf games for use as a digital biomarker of mental health.\u3cbr/\u3e\u3cbr/\u3eConclusions: When people play commercial digital games, they produce significant volumes of high-resolution data that are not only related to play frequency, but also include performance data reflecting low-level cognitive and motor processing; text-based data that are indicative of the affective state; social data that reveal networks of relationships; content choice data that imply preferred genres; and contextual data that divulge where, when, and with whom the players are playing. These data provide a source for digital biomarkers that may indicate mental health. Produced by engaged human behavior, game data have the potential to be leveraged for population screening or prevalence estimations, leading to at-scale, nonintrusive assessment of mental health

Toward game-based digital mental health interventions: player habits and preferences

\u3cp\u3eBackground: Designers of digital interventions for mental health often leverage interactions from games because the intrinsic motivation that results from game-based interventions may increase participation and translate into improved treatment efficacy. However, there are outstanding questions about the suitability (eg, are desktop or mobile interventions more appropriate?) and intervention potential (eg, do people with depression activate enough to play?) of games for mental health. Objective: In this paper, we aimed to describe the presently unknown relationship between gaming activity and indicators of well-being so that designers make informed choices when designing game-based interventions for mental health. Methods: We gathered validated scales of well-being (Beck's Depression Inventory [BDI-II], Patient Health Questionnaire [PHQ-9], trait anxiety [TA], and basic psychological needs satisfaction [BPNS]), play importance (control over game behavior: control; gamer identity: identity), and play behavior (play frequency, platform preferences, and genre preferences) in a Web-based survey (N=491). Results: The majority of our participants played games a few times a week (45.3%, 222/490) or daily (34.3%, 168/490). In terms of depression, play frequency was associated with PHQ-9 (P=.003); PHQ-9 scores were higher for those who played daily than for those who played a few times a week or less. Similarly, for BDI-II (P=.01), scores were higher for those who played daily than for those who played once a week or less. Genre preferences were not associated with PHQ-9 (P=.32) or BDI-II (P=.68); however, platform preference (ie, mobile, desktop, or console) was associated with PHQ-9 (P=.04); desktop-only players had higher PHQ-9 scores than those who used all platforms. Platform preference was not associated with BDI-II (P=.18). In terms of anxiety, TA was not associated with frequency (P=.23), platform preference (P=.07), or genre preference (P=.99). In terms of needs satisfaction, BPNS was not associated with frequency (P=.25) or genre preference (P=.53), but it was associated with platform preference (P=.01); desktop-only players had lower needs satisfaction than those who used all platforms. As expected, play frequency was associated with identity (P<.001) and control (P<.001); those who played more had identified more as a gamer and had less control over their gameplay. Genre preference was associated with identity (P<.001) and control (P<.001); those who played most common genres had higher control over their play and identified most as gamers. Platform preference was not associated with control (P=.80), but was with identity (P=.001); those who played on all devices identified more as a gamer than those who played on mobiles or consoles only. Conclusions: Our results suggest that games are a suitable approach for mental health interventions as they are played broadly by people across a range of indicators of mental health. We further unpack the platform preferences and genre preferences of players with varying levels of well-being.\u3c/p\u3

Combating attrition in digital self-improvement programs using avatar customization

Digital self-improvement programs (e.g., interventions, training programs, self-help apps) are widely accessible, but can not employ the same degree of external regulation as programs delivered in controlled environments. As a result, they suffer from high attrition -- even the best programs won't work if people don't use them. We propose that volitional engagement -- facilitated through avatar customization -- can help combat attrition. We asked 250 participants to engage daily for 3 weeks in a one-minute breathing exercise for anxiety reduction, using either a generic avatar or one that they customized. Customizing an avatar resulted in significantly less attrition and more sustained engagement as measured through login counts. The problem of attrition affects self-improvement programs across a range of do-mains; we provide a subtle, versatile, and broadly-applicable solution

Healthy lies:the effects of misrepresenting player health data on experience, behavior, and performance

Game designers use a variety of techniques that mislead players with the goal of inducing play experience. For example, designers may manipulate data displays of player health--showing they have less health than they actually do--to induce tension. While commonly used, players make decisions based on in-game data displays, raising the question of how misrepresentations impact behavior and performance, and whether this might have unintended consequences. To provide a better understanding of how data misrepresentation impacts play, we compare two versions of a game: one that displays health accurately and one that misrepresents health. Our results suggest that even subtle manipulations to data displays can have a measurable effect on behavior and performance, and these changes can help explain differences in experience. We show that data misrepresentations need to be designed carefully to avoid unintended effects. Our work provides new directions for research into the design of misrepresentation in games

DanSync:playful track selection through synchronized movements

\u3cp\u3eExperiencing synchrony with others is a powerful and engaging experience that fosters empathy, happiness, and connectedness between people. However, synchrony is underexplored in social co-located play. We developed DanSync, a system that enables multiple players to explore personalized musical characteristics through movement synchrony. We discuss the potential of synchrony between players for interactive play experiences.\u3c/p\u3

The motivational push of games: the interplay of intrinsic motivation and external rewards in games for training

\u3cbr/\u3eGames for training aim to keep interest in training activities high by making them more enjoyable, yet interest and motivation often wane over time. Games frequently employ rewards to halt waning motivation; however, research suggests that although this approach may work for less motivated players, it may backfire for players who are already enjoying a game. To explore changing motivation patterns over time, we conducted an 11-day study of a game for training executive functioning with players who were split into two groups that reflected their intrinsic motivation induced through a manipulation of identification with an in-game avatar. Although motivation waned over time, both effort and enjoyment waned more rapidly for players who identified less. After one week, when we delivered a reward (payment), the less-identified group respond positively -- increasing their effort and improving performance; however, the more identified group responded negatively -- decreasing their effort and declining in task performance.\u3cbr/\u3