To ascertain the neuroendocrine function of the kisspeptin/ GPR54 system in non-mammalian species, full-length cDNAs encoding for Kiss1 and Kiss2 as well as their putative cognate receptors GPR54a and GPR54b, were isolated from goldfish (Carassius auratus). The deduced protein sequences between Kiss1 and Kiss2 in goldfish share very low similarity, but their putative mature peptides (kisspeptin-10) are relatively conserved. RT-PCR analysis demonstrated that the goldfish kiss1 gene ( gfkiss1) is highly expressed in the optic tectum-thalamus, intestine, kidney, and testis, while the goldfish kiss2 gene ( gfkiss2) is mainly detected in the hypothalamus, telencephalon, optic tectum thalamus, adipose tissue, kidney, heart, and gonads. The two receptor genes ( gfgpr54a and gfgpr54b) are highly expressed in the brain regions including telencephalon, optic tectum thalamus, and hypothalamus. Both mature goldfish kisspeptin-10 peptides (gfKiss1-10 and gfKiss2-10) are biologically active as they could functionally interact with the two goldfish receptors expressed in cultured eukaryotic cells to trigger the downstream signaling pathways with different potencies. The actions of gfKiss1-10 and gfKiss2-10 on LH secretion were further investigated in vitro and in vivo. Intraperitoneal administration of gfKiss1-10 to sexually mature female goldfish could increase the serum LH levels. However, this peptide does not significantly influence LH release from goldfish pituitary cells in primary culture, indicating that the peptide does not exert its actions at the pituitary level. On the other hand, gfKiss2-10 appears to be a much less potent peptide as it exhibits no significant in vivo bioactivity and is also inactive on the primary pituitary cells.

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Per- and polyfluoroalkyl substances (PFAS) exposure may increase adiposity and obesity risk in children. However, no studies have extended these findings into adolescence or identified periods of heightened susceptibility. We estimated associations of repeated pre- and postnatal serum PFAS concentrations with adolescent adiposity and risk of overweight/obesity. We studied 212 mother–offspring pairs from the HOME Study. We quantified serum concentrations of four PFAS in mothers at ∼16 week gestation and their children at birth and ages 3, 8, and 12 years. We assessed adiposity at 12 years using anthropometry and dual-energy X-ray absorptiometry. Using multiple informant models, we estimated covariate-adjusted associations of an interquartile range (IQR) increase in log2-transformed PFAS for each time period with adiposity measures and tested differences in these associations. Serum perfluorooctanoate (PFOA) and perfluorohexane sulfonate (PFHxS) concentrations during pregnancy were associated with modest increases in central adiposity and risk of overweight/obesity, but there was no consistent pattern for postnatal concentrations. We observed nonlinear associations between PFOA in pregnancy and some measures of adiposity. Overall, we observed a pattern of modest positive associations of gestational PFOA and PFHxS concentrations with central adiposity and the risk of obesity in adolescents, while no pattern was observed for postnatal PFAS concentrations.

BACKGROUND: DNA methylation alterations may underlie associations between gestational perfluoroalkyl substances (PFAS) exposure and later-life health outcomes. To the best of our knowledge, no longitudinal studies have examined the associations between gestational PFAS and DNA methylation. OBJECTIVES: We examined associations of gestational PFAS exposure with longitudinal DNA methylation measures at birth and in adolescence using the Health Outcomes and Measures of the Environment (HOME) Study (2003Study ( -2006 Cincinnati, Ohio). METHODS: We quantified serum concentrations of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoate (PFNA), and perfluorohexane sulfonate (PFHxS) in mothers during pregnancy. We measured DNA methylation in cord blood (n = 266) and peripheral leukocytes at 12 years of age (n = 160) using the Illumina HumanMethylation EPIC BeadChip. We analyzed associations between log 2 -transformed PFAS concentrations and repeated DNA methylation measures using linear regression with generalized estimating equations. We included interaction terms between children's age and gestational PFAS. We performed Gene Ontology enrichment analysis to identify molecular pathways. We used Project Viva (1999-2002 Boston, Massachusetts) to replicate significant associations. RESULTS: After adjusting for covariates, 435 cytosine-guanine dinucleotide (CpG) sites were associated with PFAS (false discovery rate, q < 0:05). Specifically, we identified 2 CpGs for PFOS, 12 for PFOA, 8 for PFHxS, and 413 for PFNA; none overlapped. Among these, 2 CpGs for PFOA and 4 for PFNA were replicated in Project Viva. Some of the PFAS-associated CpG sites annotated to gene regions related to cancers, cognitive health, cardiovascular disease, and kidney function. We found little evidence that the associations between PFAS and DNA methylation differed by children's age. DISCUSSION: In these longitudinal data, PFAS biomarkers were associated with differences in several CpGs at birth and at 12 years of age in or near genes linked to some PFAS-associated health outcomes. Future studies should examine whether DNA methylation mediates associations between gestational PFAS exposure and health.

Flapping wings continuously create and send vortices into their wake, while imparting downward momentum into the surrounding fluid. However, experimental studies concerning the details of the three-dimensional vorticity distribution and evolution in the far wake are limited. In this study, the three-dimensional vortex wake structure in both the near and far field of a dynamically scaled flapping wing was investigated experimentally, using volumetric three-component velocimetry. A single wing, with shape and kinematics similar to those of a fruitfly, was examined. The overall result of the wing action is to create an integrated vortex structure consisting of a tip vortex (TV), trailing-edge shear layer (TESL) and leading-edge vortex. The TESL rolls up into a root vortex (RV) as it is shed from the wing, and together with the TV, contracts radially and stretches tangentially in the downstream wake. The downwash is distributed in an arc-shaped region enclosed by the stretched tangential vorticity of the TVs and the RVs. A closed vortex ring structure is not observed in the current study owing to the lack of well-established starting and stopping vortex structures that smoothly connect the TV and RV. An evaluation of the vorticity transport equation shows that both the TV and the RV undergo vortex stretching while convecting downwards: a three-dimensional phenomenon in rotating flows. It also confirms that convection and secondary tilting and stretching effects dominate the evolution of vorticity.

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