Dormancy awakened: aminergic control of diapause in Drosophila

Coping with adverse environmental conditions is one of the most crucial challenges for all living beings. The coupling between external cues and hormonal signaling is key to allow survivorship of individuals and insects in particular have been intensively studied to better understand this connection. Although the hormonal cascade that promotes insect development and reproduction is well known (insulin signaling - juvenile hormone – 20-Ecdysone), how this neuroendocrine axis is modulated by environmental stimuli remains still largely elusive. To deepen the molecular features of IIS-JH-20E axis regulation, we focused our attention on one of the best examples of physiological strategies triggered by environmental stimuli, diapause. Diapause is an inducible developmental arrest, which characterizes the life cycle of several species, from Caenorhabditis elegans to mammals. Our results shed new light on the regulation of key neuroendocrine pathways for growth and development, and suggest how organisms couple environmental conditions with inner hormonal physiology

Rhythms and Clocks in Marine Organisms

The regular movements of waves and tides are obvious representations of the oceans’ rhythmicity. But the rhythms of marine life span across ecological niches and timescales, including short (in the range of hours) and long (in the range of days and months) periods. These rhythms regulate the physiology and behavior of individuals, as well as their interactions with each other and with the environment. This review highlights examples of rhythmicity in marine animals and algae that represent important groups of marine life across different habitats. The examples cover ecologically highly relevant species and a growing number of laboratory model systems that are used to disentangle key mechanistic principles. The review introduces fundamental concepts of chronobiology, such as the distinction between rhythmic and endogenous oscillator–driven processes. It also addresses the relevance of studying diverse rhythms and oscillators, as well as their interconnection, for making better predictions of how species will respond to environmental perturbations, including climate change. As the review aims to address scientists from the diverse fields of marine biology, ecology, and molecular chronobiology, all of which have their own scientific terms, we provide definitions of key terms throughout the article

DON ANTE DRAČEVAC (1920-1993)

<div><p>Diapause is an actively induced dormancy that has evolved in Metazoa to resist environmental stresses. In temperate regions, many diapausing insects overwinter at low temperatures by blocking embryonic, larval or adult development. Despite its Afro-tropical origin, <i>Drosophila melanogaster</i> migrated to temperate regions of Asia and Europe where females overwinter as adults by arresting gonadal development (reproductive diapause) at temperatures <13°C. Recent work in <i>D</i>. <i>melanogaster</i> has implicated the developmental hormones dILPs-2 and/or dILP3, and dILP5, homologues of vertebrate insulin/insulin-like growth factors (IGFs), in reproductive arrest. However, polymorphisms in <i>timeless (tim)</i> and <i>couch potato (cpo)</i> dramatically affect diapause inducibility and these dILP experiments could not exclude this common genetic variation contributing to the diapause phenotype. Here, we apply an extensive genetic dissection of the insulin signaling pathway which allows us to see both enhancements and reductions in egg development that are independent of <i>tim</i> and <i>cpo</i> variations. We show that a number of manipulations dramatically enhance diapause to ~100%. These include ablating, or reducing the excitability of the insulin-producing cells (IPCs) that express dILPs-2,3,5 employing the <i>dilp2</i>,<i>3</i>,<i>5</i>^<i>-/-</i> triple mutant, desensitizing insulin signaling using a <i>chico</i> mutation, or inhibiting dILP2 and 5 in the hemolymph by over-expressing Imaginal Morphogenesis Protein-Late 2 (Imp-L2). In addition, triple mutant <i>dilp2</i>,<i>3</i>,<i>5</i>^-/- females maintain high levels of diapause even when temperatures are raised in adulthood to 19°C. However at 22°C, these females all show egg development revealing that the effects are conditional on temperature and not a general female sterility. In contrast, over-expression of <i>dilps-2/5</i> or enhancing IPC excitability, led to levels of ovarian arrest that approached zero, underscoring dILPs-2 and 5 as key antagonists of diapause.</p></div

The Nereid on the rise: Platynereis as a model system.

The Nereid Platynereis dumerilii (Audouin and Milne Edwards (Annales des Sciences Naturelles 1:195-269, 1833) is a marine annelid that belongs to the Nereididae, a family of errant polychaete worms. The Nereid shows a pelago-benthic life cycle: as a general characteristic for the superphylum of Lophotrochozoa/Spiralia, it has spirally cleaving embryos developing into swimming trochophore larvae. The larvae then metamorphose into benthic worms living in self-spun tubes on macroalgae. Platynereis is used as a model for genetics, regeneration, reproduction biology, development, evolution, chronobiology, neurobiology, ecology, ecotoxicology, and most recently also for connectomics and single-cell genomics. Research on the Nereid started with studies on eye development and spiralian embryogenesis in the nineteenth and early twentieth centuries. Transitioning into the molecular era, Platynereis research focused on posterior growth and regeneration, neuroendocrinology, circadian and lunar cycles, fertilization, and oocyte maturation. Other work covered segmentation, photoreceptors and other sensory cells, nephridia, and population dynamics. Most recently, the unique advantages of the Nereid young worm for whole-body volume electron microscopy and single-cell sequencing became apparent, enabling the tracing of all neurons in its rope-ladder-like central nervous system, and the construction of multimodal cellular atlases. Here, we provide an overview of current topics and methodologies for P. dumerilii, with the aim of stimulating further interest into our unique model and expanding the active and vibrant Platynereis community

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. materia

Notulae to the Italian alien vascular flora: 14

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as Suppl. material

Notulae to the Italian alien vascular flora: 11

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1

Dormancy awakened: aminergic control of diapause in Drosophila

Coping with adverse environmental conditions is one of the most crucial challenges for all living beings. The coupling between external cues and hormonal signaling is key to allow survivorship of individuals and insects in particular have been intensively studied to better understand this connection. Although the hormonal cascade that promotes insect development and reproduction is well known (insulin signaling - juvenile hormone – 20-Ecdysone), how this neuroendocrine axis is modulated by environmental stimuli remains still largely elusive. To deepen the molecular features of IIS-JH-20E axis regulation, we focused our attention on one of the best examples of physiological strategies triggered by environmental stimuli, diapause. Diapause is an inducible developmental arrest, which characterizes the life cycle of several species, from Caenorhabditis elegans to mammals. Our results shed new light on the regulation of key neuroendocrine pathways for growth and development, and suggest how organisms couple environmental conditions with inner hormonal physiology.Sopravvivere a drastici cambiamenti climatici rappresenta una delle sfide principali per gli esseri viventi. Gli insetti non solo forniscono esempi straordinari di adattamenti morfologici e fisiologici a climi sfavorevoli, ma sono anche molto studiati per comprendere quali sono i meccanismi molecolari responsabili di questi adattamenti. Negli insetti, i principali processi ormonali che promuovono lo sviluppo e la riproduzione sono ben noti e comprendono tre attori principali, il segnale insulinico (IIS), l’ormone giovanile (JH) e l’idrossi-ecdisone (20E). Nonostante questo importante asse neuroendocrino (IIS-JH-20E) sia ben studiato, poco si conosce riguardo i meccanismi molecolari che trasducono le informazioni ambientali ai componenti fondamentali del sistema endocrino, modulandone l’attività regolatoria. Per questo abbiamo rivolto la nostra attenzione ad uno degli esempi più interessanti di strategie fisiologiche evocate dagli stimoli esterni, la diapausa, un arresto dello sviluppo inducibile che rappresenta un evento estremamente diffuso nel regno animale. I nostri risultati forniscono un contributo alla comprensione degli aspetti regolativi dei meccanismi neuroendocrini fondamentali per la crescita, lo sviluppo e la riproduzione, e suggeriscono alcune modalità con le quali gli insetti accoppiano la percezione delle condizioni ambientali con la loro fisiologia ormonale