BackgroundPregnancy intention is important for maternal and child health outcomes. The purpose of this study was to examine the causal relation between pregnancy intention and maternal depression and parenting stress in Korean women who gave birth during 2008.MethodsThis study is a retrospective evaluation of prospectively collected data from the Panel Study on Korean Children from 2008 to 2010. Causal analyses were conducted using propensity score matching and inverse probability of treatment weighted methods. In addition, mediation analyses were performed to test mitigating effects of marital conflict, fathers’ participation in childcare, and mothers’ knowledge of infant development on the relation between unintended pregnancy and adverse maternal mental health.ResultsResults showed that the overall effect of an unintended pregnancy on maternal depression and parenting stress was statistically significant. An unintended pregnancy was associated with 20–22% greater odds of maternal depression, 0.28–0.39 greater depression score, and 0.85–1.16 greater parenting stress score. Relations between pregnancy intention and maternal depression, maternal depression score and parenting stress score were moderately explained by marital conflict and fathers’ participation in childcare.ConclusionsUnintended pregnancy contributed to increased risks of maternal depression and parenting stress. Efforts to increase fathers’ participation in childcare and decrease marital conflict might be helpful to mitigate adverse impacts of unintended pregnancy on perinatal maternal mental health.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-015-0505-4) contains supplementary material, which is available to authorized users.

Summary Circadian rhythm is altered during aging, although the underlying molecular mechanisms remain largely unknown. Here, we used the turquoise killifish as a short-lived vertebrate model to examine the effects of aging on the major circadian network comprising the four mammalian clock protein homologs, Bmal1, Clockb, Cry1b, and Per3, which are highly conserved in the killifish with 50%–85% amino acid sequence identity to their human counterparts. The amplitude of circadian rhythm was smaller in old fish (14 weeks) than in young fish (6 weeks). In old fish brain, the Bmal1 protein level was significantly downregulated. However, the Bmal1 interaction with Clockb and chromatin binding of Bmal1 to its downstream target promoters were retained. Furthermore, Bmal1 was relatively well maintained in the pineal gland compared with other regions of the old fish brain. The results suggest that the circadian clock system in the killifish becomes spatially confined to the pineal gland upon aging.

Summary Ribosomes are composed of a mix of ribosomal RNAs and proteins; this composition varies depending on time, condition, and organism. Here, we present an optimized protocol for preparation of intact ribosomes from the skeletal muscle of the turquoise killifish. We also detail the steps for ribosome quantification and cryo-EM grid preparation. This protocol can enable the identification of heterogeneous ribosome structures that vary by fish age or in response to specific conditions.

The hypophysis functions as a central gland of the neuroendocrine system for regulating fundamental body physiology. Upon aging, several hormones produced by the endocrine system are dramatically altered. Recently, Nothobranchius furzeri (the turquoise killifish) has become a popular model for aging studies because of its short lifespan and highly conserved aging phenotypes. However, the anatomical details of the major neuroendocrine system of the killifish have not been investigated so far. In this study, we have identified the pituitary and pineal glands of the turquoise killifish, which are critical components of the brain endocrine system. These two neuroendocrine glands were weakly attached to the main body of the killifish brain. The pineal gland was located on the dorsal part of the brain, while the pituitary gland was located on the ventral part. Brain sections containing pineal and pituitary glands were performed and revealed that cells in both the pituitary and pineal glands are densely placed than any other regions of brain. Further, three-dimensional images both in pineal and pituitary glands were uncovered their distinctive cellular arrangements. Vasopressin intestinal peptide (VIP) was strongly expressed in the neurohypophysis of the pituitary gland. Glial cells were found inside the pineal gland, while astrocytes covered the outside. These findings illustrate basic features of the neuroendocrine system of Nothobranchius furzeri.

Summary Distribution of cells and proteins in whole organs, such as the brain, can provide another level of insight into molecular and cellular functions. Here, we describe a whole-brain immunostaining method using the turquoise killifish, an emerging model for aging research. We optimized a protocol for tissue clearing and whole-brain immunostaining to the turquoise killifish brain. This protocol provides a comprehensive procedure from brain dissection to whole-brain imaging and image processing. For complete details on the use and execution of this protocol, please refer to Eunjeong Do (2020) and Lee et al. (2021) .