The formation of Jupiter's diluted core by a giant impact.

The Juno mission has provided an accurate determination of Jupiter's gravitational field, which has been used to obtain information about the planet's composition and internal structure. Several models of Jupiter's structure that fit the probe's data suggest that the planet has a diluted core, with a total heavy-element mass ranging from ten to a few tens of Earth masses (about 5 to 15 per cent of the Jovian mass), and that  heavy elements (elements other than hydrogen and helium) are distributed within a region extending to nearly half of Jupiter's radius. Planet-formation models indicate that most heavy elements are accreted during the early stages of a planet's formation to create a relatively compact core and that almost no solids are accreted during subsequent runaway gas accretion.

Exoplanet Biosignatures: Observational Prospects.

Exoplanet hunting efforts have revealed the prevalence of exotic worlds with diverse properties, including Earth-sized bodies, which has fueled our endeavor to search for life beyond the Solar System. Accumulating experiences in astrophysical, chemical, and climatological characterization of uninhabitable planets are paving the way to characterization of potentially habitable planets. In this paper, we review our possibilities and limitations in characterizing temperate terrestrial planets with future observational capabilities through the 2030s and beyond, as a basis of a broad range of discussions on how to advance "astrobiology" with exoplanets.

Neural networks of several novel neuropeptides involved in feeding regulation.

Novel neuropeptides acting as G-protein-coupled receptor (GPCR) ligands are known to be localized in the brain and play a range of physiologic functions, one of which is feeding regulation. We describe the distribution and localization of these recently identified GPCR ligands and review their involvement in neuronal networks, particularly in feeding regulation. This review addresses aspects of some novel GPCR ligands, including feeding-regulating neuropeptides such as orexin, ghrelin, and galanin-like peptide and other known neuropeptides such as neuropeptide Y and pro-opiomelanocortin.

Visualization of ghrelin-producing neurons in the hypothalamic arcuate nucleus using ghrelin-EGFP transgenic mice.

The gut-brain hormone ghrelin is known to stimulate growth hormone release from the pituitary gland, and to regulate appetite and energy metabolism. Ghrelin-containing neurons have been shown to form neuronal network with several types of appetite-regulating neurons in the hypothalamus. Although ghrelin-containing cell bodies have been reported to localize in the hypothalamic arcuate nucleus, the published results present large discrepancies regarding the localization of ghrelin-positive cell bodies in the brain.

Synaptic relationships between proopiomelanocortin- and ghrelin-containing neurons in the rat arcuate nucleus.

Both proopiomelanocortin (POMC) and ghrelin peptides are implicated in the feeding regulation. The synaptic relationships between POMC- and ghrelin-containing neurons in the hypothalamic arcuate nucleus were studied using double-immunostaining methods at the light and electron microscope levels. Many POMC-like immunoreactive axon terminals were found to be apposed to ghrelin-like immunoreactive neurons and also to make synapses with ghrelin-like immunoreactive neuronal perikarya and dendritic processes.

Synaptic interaction between ghrelin- and ghrelin-containing neurons in the rat hypothalamus.

Synaptic relationships between ghrelin-like immunoreactive axon terminals and other neurons in the hypothalamic arcuate nucleus (ARC) were studied using immunostaining methods at the light and electron microscope levels. Many ghrelin-like immunoreactive axon terminals were found to be in apposition to ghrelin-like immunoreactive neurons at the light microscopic level. At the electron microscopic level, ghrelin-like immunoreactive axon terminals were found to make synapses on ghrelin-like immunoreactive cell bodies and dendrites in the ARC.

Morphological interaction between galanin-like peptide- and dopamine-containing neurons in the rat arcuate nucleus.

Galanin-like peptide (GALP) is a 60-amino acid neuropeptide that plays an important role in the neuronal regulation of feeding, energy balance and reproduction. GALP is produced in the hypothalamic arcuate nucleus, an area containing, amongst other neuron types, two populations of neurons in which we were interested: a population of GALP-containing neurons which regulate energy balance and reproduction, and a second population consisting of tuberoinfundibular dopaminergic neurons which suppress prolactin secretion from the adenohypophysis. To characterize morphologically the relationship between GALP and dopamine-containing neurons in the arcuate nucleus, a double immunofluorescence study was performed on cryosections from rat brain.

Valproate-induced developmental neurotoxicity is affected by maternal conditions including shipping stress and environmental change during early pregnancy.

Prenatal stress is known to affect the development of the brain, and exaggerate the developmental toxicity of chemicals. Many studies of developmental neurotoxicity (DNT) use pregnant rodents mated at the supplier, which consequently suffer from the stress of shipping and of environmental changes. Here, we demonstrated differences in the developmental neurotoxicity induced by valproate (VPA) between pregnant rats mated at our own animal facility (in-house group) and rats purchased pregnant (supplier group).

Relationships between insulin release and taste.

Tasting sweet food elicits insulin release prior to increasing plasma glucose levels, known as cephalic phase insulin release (CPIR). The characteristic of CPIR is that plasma insulin secretion occurs before the rise of the plasma glucose level. In this experiment, we examined whether taste stimuli placed on the tongue could induce CPIR.