Integration of physiological responses of crustaceans to environmental challenge

Brachyuran crustaceans are useful models for physiological studies because of their intermediate size and since they occupy a spectrum of habitats requiring widely varied behaviour. In this paper we examine the physiological responses to environmental fluctuations, extremes of habitat and consequent behaviours, with special emphasis on the adoption of air-breathing. It is established that metabolic end products such as lactate, intermediates including urate, and monoamine and peptide neurohormones can have important regulatory roles. These include effects on ventilation and heart function, blood perfusion, respiratory gas transport, as well as water and salt homeostasis providing an integrated suite of control mechanisms to regulate responses to environmental or behaviourally induced stress. A separate body of work has long suggested that the regulation of energy metabolism and provision of metabolic fuel for glycolysis is influenced by similar effectors. Most recently, metabolic end-products have been implicated as effectors of behaviour and thereby metabolic state. Thus, there is strong, emerging evidence for integration of physiological control mechanisms at the organismal level. We present new information, both mechanistic and from eco-physiological laboratory simulations, and from field studies of terrestrial crabs, that strengthens and extends the scope of this integration. Branchial chamber ventilation, cardiovascular function, relative perfusion of gills v. lungs, gas transport in the blood, the mobilisation of energy reserves, ion transport and water balance are all apparently influenced by similar messengers which coordinate and optimise these functions to meet specific requirements

Contemporary Ethnic Geographies in America

Terry-Ann Jones (with Thomas D. Boswell) is a contributing author, Caribbean Hispanics: Puerto Ricans, Cubans, and Dominicans”, pp. 123-150. Book description: Ethnic diversity has marked the United States from its inception. From the migration of the ancestors of Native Americans to the increasingly diverse immigrant populations arriving today, it is impossible to separate ethnicity from an understanding of the United States as a country and Americans as a people. At an ever-increasing pace, America today is experiencing watershed changes in its social, cultural, and ethnic/racial geographies. Considering the impact of these transformations, this unique text examines the experiences of a range of ethnic groups in both historical and contemporary context. It begins by laying out a comprehensive conceptual framework that integrates immigration theory; globalization; transnational community formation; and urban, cultural, and economic geography. The contributors then present a rich set of case studies of key ethnic and racial communities—including those of long-standing significance such as Native Americans, African Americans, and Mexican Americans, along with the Latin American and Asian groups that make up the vast majority of newer immigrants. Each case offers a brief historical overview of the group\u27s immigration experience and settlement patterns and discusses its contemporary dynamics. All of these people have transformed—and been transformed by—the places in which they have settled. Exploring these changing communities, places, and landscapes, this book offers a nuanced understanding of the evolution of America\u27s contemporary ethnic geographies.https://digitalcommons.fairfield.edu/sociologyandanthropology-books/1023/thumbnail.jp

The effects of changing climate on faunal depth distributions determine winners and losers

Changing climate is predicted to impact all depths of the global oceans, yet projections of range shifts in marine faunal distributions in response to changing climate seldom evaluate potential shifts in depth distribution. Marine ectotherms’ thermal tolerance is limited by their ability to maintain aerobic metabolism (oxygen- and capacity-limited tolerance), and is functionally associated with their hypoxia tolerance. Shallow-water (<200 m depth) marine invertebrates and fishes demonstrate limited tolerance of increasing hydrostatic pressure (pressure exerted by the overlying mass of water), and hyperbaric (increased pressure) tolerance is proposed to depend on the ability to maintain aerobic metabolism, too. Here, we report significant correlation between the hypoxia thresholds and the hyperbaric thresholds of taxonomic groups of shallow-water fauna, suggesting that pressure tolerance is indeed oxygen-limited. Consequently, it appears that the combined effects of temperature, pressure, and oxygen concentration constrain the fundamental ecological niches (FENs) of marine invertebrates and fishes. Including depth in a conceptual model of oxygen- and capacity-limited FENs’ responses to ocean warming and deoxygenation confirms previous predictions made based solely on consideration of the latitudinal effects of ocean warming (e.g. Cheung et al., 2009), that polar taxa are most vulnerable to the effects of climate change, with Arctic fauna experiencing the greatest FEN contraction. In contrast, the inclusion of depth in the conceptual model reveals for the first time that temperate fauna as well as tropical fauna may experience substantial FEN expansion with ocean warming and deoxygenation, rather than FEN maintenance or contraction suggested by solely considering latitudinal range shifts

Derivation of High Purity Neuronal Progenitors from Human Embryonic Stem Cells

The availability of human neuronal progenitors (hNPs) in high purity would greatly facilitate neuronal drug discovery and developmental studies, as well as cell replacement strategies for neurodegenerative diseases and conditions, such as spinal cord injury, stroke, Parkinson's disease, Alzheimer's disease, and Huntington's disease. Here we describe for the first time a method for producing hNPs in large quantity and high purity from human embryonic stem cells (hESCs) in feeder-free conditions, without the use of exogenous noggin, sonic hedgehog or analogs, rendering the process clinically compliant. The resulting population displays characteristic neuronal-specific markers. When allowed to spontaneously differentiate into neuronal subtypes in vitro, cholinergic, serotonergic, dopaminergic and/or noradrenergic, and medium spiny striatal neurons were observed. When transplanted into the injured spinal cord the hNPs survived, integrated into host tissue, and matured into a variety of neuronal subtypes. Our method of deriving neuronal progenitors from hESCs renders the process amenable to therapeutic and commercial use

Short-term acclimation in adults does not predict offspring acclimation potential to hypoxia

Abstract The prevalence of hypoxic areas in coastal waters is predicted to increase and lead to reduced biodiversity. While the adult stages of many estuarine invertebrates can cope with short periods of hypoxia, it remains unclear whether that ability is present if animals are bred and reared under chronic hypoxia. We firstly investigated the effect of moderate, short-term environmental hypoxia (40% air saturation for one week) on metabolic performance in adults of an estuarine amphipod, and the fitness consequences of prolonged exposure. We then reared the offspring of hypoxia-exposed parents under hypoxia, and assessed their oxyregulatory ability under declining oxygen tensions as juveniles and adults. Adults from the parental generation were able to acclimate their metabolism to hypoxia after one week, employing mechanisms typically associated with prolonged exposure. Their progeny, however, did not develop the adult pattern of respiratory regulation when reared under chronic hypoxia, but instead exhibited a poorer oxyregulatory ability than their parents. We conclude that species apparently hypoxia-tolerant when tested in short-term experiments, could be physiologically compromised as adults if they develop under hypoxia. Consequently, we propose that the increased prevalence of hypoxia in coastal regions will have marked effects in some species currently considered hypoxia tolerant

Differential Modulation of Beta-Adrenergic Receptor Signaling by Trace Amine-Associated Receptor 1 Agonists

Trace amine-associated receptors (TAAR) are rhodopsin-like G-protein-coupled receptors (GPCR). TAAR are involved in modulation of neuronal, cardiac and vascular functions and they are potentially linked with neurological disorders like schizophrenia and Parkinson's disease. Subtype TAAR1, the best characterized TAAR so far, is promiscuous for a wide set of ligands and is activated by trace amines tyramine (TYR), phenylethylamine (PEA), octopamine (OA), but also by thyronamines, dopamine, and psycho-active drugs. Unfortunately, effects of trace amines on signaling of the two homologous β-adrenergic receptors 1 (ADRB1) and 2 (ADRB2) have not been clarified yet in detail. We, therefore, tested TAAR1 agonists TYR, PEA and OA regarding their effects on ADRB1/2 signaling by co-stimulation studies. Surprisingly, trace amines TYR and PEA are partial allosteric antagonists at ADRB1/2, whereas OA is a partial orthosteric ADRB2-antagonist and ADRB1-agonist. To specify molecular reasons for TAAR1 ligand promiscuity and for observed differences in signaling effects on particular aminergic receptors we compared TAAR, tyramine (TAR) octopamine (OAR), ADRB1/2 and dopamine receptors at the structural level. We found especially for TAAR1 that the remarkable ligand promiscuity is likely based on high amino acid similarity in the ligand-binding region compared with further aminergic receptors. On the other hand few TAAR specific properties in the ligand-binding site might determine differences in ligand-induced effects compared to ADRB1/2. Taken together, this study points to molecular details of TAAR1-ligand promiscuity and identified specific trace amines as allosteric or orthosteric ligands of particular β-adrenergic receptor subtypes

Conflict-induced displacement as a catalyst for agricultural innovation: findings from South Sudan

This article explores how conflict-induced displacement influences agricultural innovation processes and systems, and its implications after the return home or permanent resettlement of smallholder farmers. Results show that high rates of agricultural innovation occurred during displacement in the Sudanese Civil War (1983-2005), many of which were maintained afterwards. Respondents cited the need for adaptation to new social and physical circumstances, changed gender roles, and enhanced inter-household communication as contributing to increased opportunities for knowledge exchange, trade, and importantly, the development of new networks, modes of organisation and social norms. Furthermore, returnees to South Sudan have embodied these changes together with new values, habits and expectations. New linkages continued across borders between returnees and non-returnees, facilitating knowledge exchange and access to resources, markets and sources of ideas. A high degree of autonomous innovation capacity was also evident. Further research is required on the dynamics and processes associated with innovation in conflict-induced displacement. It is important for policy makers to encourage approaches that seek to actively tap into and build on the institutional, human and social capital built during displacement

Port-Centered Transport Development in Colonial North Sumatra

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