Transcriptional regulation analysis reveals the complexity of metamorphosis in the Pacific oyster (Crassostrea gigas).

Many marine invertebrate phyla are characterized by indirect development. These animals transit from planktonic larvae to benthic spats via settlement and metamorphosis, which contributes to their adaption to the marine environment. Studying the biological process of metamorphosis is, thus, key to understanding the origin and evolution of indirect development. Although numerous studies have been conducted on the relationship between metamorphosis and the marine environment, microorganisms, and neurohormones, little is known about gene regulation network (GRN) dynamics during metamorphosis. Metamorphosis-competent pediveligers of the Pacific oyster Crassostrea gigas were assayed in this study. By assaying gene expression patterns and open chromatin region changes of different samples of larvae and spats, the dynamics of molecular regulation during metamorphosis were examined. The results indicated significantly different gene regulation networks before, during and post-metamorphosis. Genes encoding membrane-integrated receptors and those related to the remodeling of the nervous system were upregulated before the initiation of metamorphosis. Massive biogenesis, e.g., of various enzymes and structural proteins, occurred during metamorphosis as inferred from the comprehensive upregulation of the protein synthesis system post epinephrine stimulation. Hierarchical downstream gene networks were then stimulated. Some transcription factors, including homeobox, basic helix-loop-helix and nuclear receptors, showed different temporal response patterns, suggesting a complex GRN during the transition stage. Nuclear receptors, as well as their retinoid X receptor partner, may participate in the GRN controlling oyster metamorphosis, indicating an ancient role of the nuclear receptor regulation system in animal metamorphosis. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00204-y.

Yoga for Preventive Health: A Holistic Approach.

Yoga has been prevalent for over 5000 years; it originated in India and has become an essential lifestyle ingredient for achieving optimal health. The goal of this article in lifestyle modification is to increase awareness about the benefits of yoga and how its practice can reduce the overall risk of chronic diseases. Yoga has been proven to be therapeutic for enhancing immunity and support management of chronic diseases such as cardiovascular, respiratory, endocrine disorders, obesity, cancer, and metabolic syndrome. Yoga techniques called asanas, such as pranayama for breathing regulation and dhyana for meditation, boost innate immune response, interrupt inflammation, and thereby prevent the manifestation of chronic diseases. Yoga also provides symptomatic relief for chronic arthritis by increasing joint flexibility and microcirculation. Yoga and meditation regulate neurotransmitters, neuropeptides, hormones, and cytokines that mediate interactions between the central nervous system and the immune system. These techniques reduce the psychological and physiological effects of chronic stress. Serotonin, oxytocin, and melatonin released directly due to practicing yoga have been shown to better manage anxiety and fear, especially during the pandemic. We believe the current trends of chronic disease management will become more effective with the implementation of lifestyle changes using yoga.

Parallel trajectories in the discovery of the SCN-OVLT and pituitary portal pathways: Legacies of Geoffrey Harris.

A map of central nervous system organization based on vascular networks provides a layer of organization distinct from familiar neural networks or connectomes. As a well-established example, the capillary networks of the pituitary portal system enable a route for small amounts of neurochemical signals to reach local targets by traveling along specialized pathways, thereby avoiding dilution in the systemic circulation. The first evidence of such a pathway in the brain came from anatomical studies identifying a portal pathway linking the hypothalamus and the pituitary gland. Almost a century later, we demonstrated a vascular portal pathway that joined the capillary beds of the suprachiasmatic nucleus and a circumventricular organ, the organum vasculosum of the lamina terminalis, in a mouse brain. For each of these portal pathways, the anatomical findings opened many new lines of inquiry, including the determination of the direction of flow of information, the identity of the signal that flowed along this pathway, and the function of the signals that linked the two regions. Here, we review landmark steps to these discoveries and highlight the experiments that reveal the significance of portal pathways and more generally, the implications of morphologically distinct nuclei sharing capillary beds.

Injected serotonin decreases foraging aggression in black widow spiders (Latrodectus hesperus), but dopamine has no effect.

A fundamental goal of animal behavior research is to discover the proximate mechanisms driving individual behavioral differences. Biogenic amines are known to mediate various aspects of behavior across many species, including aggression, one of the most commonly measured behavioral traits in animals. Arthropods provide an excellent system to manipulate biogenic amines and quantify subsequent behavioral changes. Here, we investigated the role of dopamine (DA) and serotonin (5-HT) on foraging aggression in western black widow spiders (Latrodectus hesperus), as measured by the number of attacks on a simulated prey animal in the web. We injected spiders with DA or 5-HT and then quantified subsequent changes in behavior over 48 h. Based on previous work on insects and spiders, we hypothesized that increasing DA levels would increase aggression, while increasing 5-HT would decrease aggression. We found that injection of 5-HT did decrease black widow foraging aggression, but DA had no effect. This could indicate that the relationship between DA and aggression is complex, or that DA may not play as important a role in driving aggressive behavior as previously thought, at least in black widow spiders. Aggressive behavior is likely also influenced by other factors, such as inter-individual differences in genetics, metabolic rates, environment, and other neurohormonal controls.

Structural and molecular characterization of paraventricular thalamic glucokinase-expressing neuronal circuits in the mouse.

The thalamic paraventricular nucleus (PVT) is a structure highly interconnected with several nuclei ranging from forebrain to hypothalamus and brainstem. Numerous rodent studies have examined afferent and efferent connections of the PVT and their contribution to behavior, revealing its important role in the integration of arousal cues. However, the majority of these studies used a region-oriented approach, without considering the neuronal subtype diversity of the nucleus. In the present study, we provide the anatomical and transcriptomic characterization of a subpopulation of PVT neurons molecularly defined by the expression of glucokinase (Gck). Combining a genetically modified mouse model with viral tracing approaches, we mapped both the anterograde and the retrograde projections of Gck-positive neurons of the anterior PVT (GckaPVT ). Our results demonstrated that GckaPVT neurons innervate several nuclei throughout the brain axis. The strongest connections are with forebrain areas associated with reward and stress and with hypothalamic structures involved in energy balance and feeding regulation. Furthermore, transcriptomic analysis of the Gck-expressing neurons revealed that they are enriched in receptors for hypothalamic-derived neuropeptides, adhesion molecules, and obesity and diabetes susceptibility transcription factors. Using retrograde labeling combined with immunohistochemistry and in situ hybridization, we identify that GckaPVT neurons receive direct inputs from well-defined hypothalamic populations, including arginine-vasopressin-, melanin-concentrating hormone-, orexin-, and proopiomelanocortin-expressing neurons. This detailed anatomical and transcriptomic characterization of GckaPVT neurons provides a basis for functional studies of the integration of homeostatic and hedonic aspects of energy homeostasis, and for deciphering the potential role of these neurons in obesity and diabetes development.

Direct effect of hypothalamic neuropeptides on the release of catecholamines by adrenal medulla in sheep - study ex vivo.

Stress causes the activation of both the hypothalamic-pituitary-adrenocortical axis and sympatho-adrenal system, thus leading to the release from the adrenal medulla of catecholamines: adrenaline and, to a lesser degree, noradrenaline. It has been established that in addition to catecholamines, the adrenomedullary cells produce a variety of neuropeptides, including corticoliberine (CRH), vasopressin (AVP), oxytocin (OXY) and proopiomelanocortine (POMC) - a precursor of the adrenocorticotropic hormone (ACTH). The aim of this study was to investigate adrenal medulla activity in vitro depending, on a dose of CRH, AVP and OXY on adrenaline and noradrenaline release. Pieces of sheep adrenal medulla tissue (about 50 mg) were put on 24-well plates and were incubated in 1 mL of Eagle medium without hormone (control) or supplemented only once with CRH, AVP and OXY in three doses (10-7, 10-8 and 10-9 M) in a volume of 10 µL. The results showed that CRH stimulates adrenaline and noradrenaline release from the adrenal medulla tissue. The stimulating influence of AVP on adrenaline release was visible after the application of the two lower doses of this neuropeptide; however, AVP reduced noradrenaline release from the adrenal medulla tissue. A strong, inhibitory OXY effect on catecholamine release was observed, regardless of the dose of this hormone. Our results indicate the important role of OXY in the inhibition of adrenal gland activity and thus a better adaptation to stress on the adrenal gland level.