second model, the two main conditions were parametrically modulated by the two categories, respectively (SOM, S5.1). The activation of the precuneus was higher for hard dominance-solvable games than for easy ones ( Fig. 4A and table S10). The activation of the insula was higher for the highly focal coordination games than for less focal ones ( Fig. 4B and table S11). Previous studies also found that precuneus activity increased when the number of planned moves increased (40, 41). The higher demand for memory-related imagery and memory retrieval may explain the greater precuneus activation in hard dominance-solvable games. In highly focal coordination games, the participants may have felt quite strongly that the pool students must notice the same salient feature. This may explain why insula activation correlates with NCI.Participants might have disagreed about which games were difficult. We built a third model to investigate whether the frontoparietal activation correlates with how hard a dominance-solvable game is and whether the activation in insula and ACC correlates with how easy a coordination game is. Here, the two main conditions were parametrically modulated by each participant's probability of obtaining a reward in each game (SOM, S2.2 and S5.2). We found a negative correlation between the activation of the precuneus and the participant's probability of obtaining a reward in dominance-solvable games ( Fig. 4C and table S12), which suggests that dominance-solvable games that yielded lower payoffs presented harder mental challenges. In a previous study on working memory, precuneus activity positively correlated with response times, a measure of mental effort (24). Both findings are consistent with the interpretation that subjective measures reflecting harder tasks (higher efforts) correlate with activation in precuneus. A positive correlation between insula activation and the participant's probability of obtaining a reward again suggests that coordination games with a highly salient feature strongly activated the "gut feeling" reported by many participants (Fig. 4D and table S13). A previous study found that the subjective rating of "chills intensity" in music correlates with activation of insula (42). Both findings are consistent with the interpretation that the subjective intensity of how salient a stimulus is correlates with activation in insula.As mentioned, choices were made significantly faster in coordination games than in dominancesolvable games. The results of the second and third models provide additional support for the idea that intuitive and deliberative mental processes have quite different properties. The "slow and effortful" process was more heavily taxed when the dominance-solvable games were harder. The "fast and effortless" process was more strongly activated when coordination was easy.

Melatonin has been used to promote in vitro embryo development in different species. This study determined the effects of melatonin on in vitro porcine embryo development; in particular, cleavage rate, blastocyst rate, and blastocyst cell number. Starting 5 hr after insemination, porcine zygotes were cultured in porcine zygote medium 3 (PZM-3) culture medium supplemented with melatonin at increasing concentrations (10(-12) M, 10(-9) M, 10(-6) M, 10(-3) M). Melatonin at a concentration of 10(-9) M had a positive effect on cleavage rates, while the highest concentration of melatonin (10(-3) M) significantly decreased cleavage rates. Although blastocyst rates were not increased by 10(-9) M melatonin, blastocyst cell numbers were significantly higher for embryos subjected to 10(-9) M melatonin. The expression levels of the pro-apoptotic gene BAX and anti-apoptotic gene BCL2L1 in blastocysts were not affected by the presence of melatonin in the culture medium. To further study the protective properties of 10(-9) M melatonin against stressful conditions, hydrogen peroxide (0.01 mm) and heat (40 degrees C) were used during embryo culture. The addition of melatonin to embryos subjected to 40 degrees C for 3 hr increased cleavage rates, but had no protective effect for embryos subjected to 0.01 mm H(2)O(2), probably because the physiological levels of melatonin could not counteract the pharmacological levels of H(2)O(2). Our data indicate that 10(-9) M melatonin has a positive effect on porcine embryo cleavage rates and blastocyst total cell numbers and it might have a protective effect against heat stress.

The use of Assisted Reproductive Technologies (ARTs) in modern cattle breeding is an important tool for improving the production of dairy and beef cattle. A frequently employed ART in the cattle industry is in vitro production of embryos. However, bovine in vitro produced embryos differ greatly from their in vivo produced counterparts in many facets, including developmental competence. The lower developmental capacity of these embryos could be due to the stress to which the gametes and/or embryos are exposed during in vitro embryo production, specifically ovarian hormonal stimulation, follicular aspiration, oocyte in vitro maturation in hormone supplemented medium, sperm handling, gamete cryopreservation, and culture of embryos. The negative effects of some ARTs on embryo development could, at least partially, be explained by disruption of the physiological epigenetic profile of the gametes and/or embryos. Here, we review the current literature with regard to the putative link between ARTs used in bovine reproduction and epigenetic disorders and changes in the expression profile of embryonic genes. Information on the relationship between reproductive biotechnologies and epigenetic disorders and aberrant gene expression in bovine embryos is limited and novel approaches are needed to explore ways in which ARTs can be improved to avoid epigenetic disorders.

Spermatozoa deliver more than the paternal genome into the oocyte; they also carry remnant messenger RNA from spermatogenesis. The RNA profiles of spermatozoa from high-fertility and a low-fertility Holstein bulls were analysed using Affymetrix bovine genechips. A total of 415 transcripts out of approximately 24,000 were differentially detected in spermatozoa collected from both bulls (fold change > or =2.0; P<0.01). These transcripts were associated with different cellular functions and biological processes. Spermatozoa from high-fertility bulls contained higher concentrations of transcripts for membrane and extracellular space protein locations, while spermatozoa from the low-fertility bulls were deficient of transcripts for transcriptional and translational factors. Quantitative real-time PCR was used on three low-fertility and four high-fertility bulls to validate the microarray data. Two highly represented transcripts in the microarray analysis (protamine 1 and casein beta 2) were validated, as well as a third transcript (thrombospondin receptor CD36 molecule) that showed a lower concentration in low-fertility bulls. This study presents the global analysis of spermatozoa originating from bulls with opposite fertility. These results provide some specific transcripts in spermatozoa that could be associated with bull fertility.

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Background: Successful reprogramming of a somatic genome to produce a healthy clone by somatic cells nuclear transfer (SCNT) is a rare event and the mechanisms involved in this process are poorly defined. When serial or successive rounds of cloning are performed, blastocyst and full term development rates decline even further with the increasing rounds of cloning. Identifying the "cumulative errors" could reveal the epigenetic reprogramming blocks in animal cloning.

Fertilization of an egg by a spermatozoon sets the stage for mammalian development. Viable sperm are a prerequisite for successful fertilization and beyond. Spermatozoa have a unique cell structure where haploid genomic DNA is located in a tiny cytoplasmic space in the head, mitochondria in the midpiece and then the tail, all enclosed by several layers of membrane. Proteins in sperm play vital roles in motility, capacitation, fertilization, egg activation and embryo development. Molecular defects in these proteins are associated with low fertility or in some cases, infertility. This review will first summarize genesis, molecular anatomy and physiology of spermatozoa, fertilization, embryogenesis and then those proteins playing important roles in various aspects of sperm physiology.