Acute toxicity of bisphenol A and its structural analogues and transcriptional modulation of the ecdysone-mediated pathway in the brackish water flea Diaphanosoma celebensis.

Bisphenol A (BPA) is a representative endocrine disrupting chemical (EDC) that has estrogenic effects in aquatic animals. In recent years, due to the continuing usage of BPA, its analogues have been developed as alternative substances to replace its use. The molting process is a pivotal point in the development and reproduction of crustaceans. However, studies of the effects of EDCs on molting in crustaceans at the molecular level are scarce. In the present study, we examined the acute toxicity of BPA and its analogues bisphenol F (BPF) and S (BPS) to the brackish water flea Diaphanosoma celebensis. We further identified four ecdysteroid pathway - related genes (cyp314a1, EcRA, EcRB, and USP) in D. celebensis, and investigated the transcriptional modulation of these genes during molting and after exposure to BPA and its analogues for 48 h. Sequencing and phylogenetic analyses revealed that these four genes are highly conserved among arthropods and may be involved in development and reproduction in the adult stage. The mRNA expression patterns of cyp314a1, EcRA and USP were matched with the molting cycle, suggesting that these genes play a role in the molting process in the adult stage in cladocerans. Following relative real-time polymerase chain reaction (RT-PCR) analyses, BPA and its analogues were found to modulate the expression of each of these four genes differently, indicating that these compounds can disrupt the normal endocrine system function of D. celebensis. This study improves our understanding of the molecular mode of action of BPA and its analogues in D. celebensis.

Factors predicting smoking in a laboratory-based smoking-choice task.

This study aimed to expand the current understanding of smoking maintenance mechanisms by examining how putative relapse risk factors relate to a single behavioral smoking choice using a novel laboratory smoking-choice task. After 12 hr of nicotine deprivation, participants were exposed to smoking cues and given the choice between smoking up to two cigarettes in a 15-min window or waiting and receiving four cigarettes after a delay of 45 min. Greater nicotine dependence, higher impulsivity, and lower distress tolerance were hypothesized to predict earlier and more intensive smoking. Out of 35 participants (n = 9 women), 26 chose to smoke with a median time to a first puff of 1.22 min (SD = 2.62 min, range = 0.03-10.62 min). Survival analyses examined latency to first puff, and results indicated that greater pretask craving and smoking more cigarettes per day were significantly related to smoking sooner in the task. Greater behavioral disinhibition predicted shorter smoking latency in the first 2 min of the task, but not at a delay of more than 2 min. Lower distress tolerance (reporting greater regulation efforts to alleviate distress) was related to more puffs smoked and greater nicotine dependence was related to more time spent smoking in the task. This novel laboratory smoking-choice paradigm may be a useful laboratory analog for the choices smokers make during cessation attempts and may help identify factors that influence smoking lapses.

Using game theory to examine incentives in influenza vaccination behavior.

The social good often depends on the altruistic behavior of specific individuals. For example, epidemiological studies of influenza indicate that elderly individuals, who face the highest mortality risk, are best protected by vaccination of young individuals, who contribute most to disease transmission. To examine the conditions under which young people would get vaccinated to protect elderly people, we conducted a game-theory experiment that mirrored real-world influenza transmission, with "young" players contributing more than "elderly" players to herd immunity. Participants could spend points to get vaccinated and reduce the risk of influenza. When players were paid according to individual point totals, more elderly than young players got vaccinated, a finding consistent with the Nash equilibrium predicting self-interested behavior. When players were paid according to group point totals, however, more young than elderly players got vaccinated-a finding consistent with the utilitarian equilibrium predicting group-optimal behavior-which resulted in higher point totals than when players were paid for their individual totals. Thus, payout structure affected whether individuals got vaccinated for self-interest or group benefit.