Effects of Aging on the Interaction Between Glutamate, Dopamine, and GABA in Striatum and Nucleus Accumbens of the Awake Rat

The aim of the present study was to investigate, using microdialysis, the effects of aging on the glutamate/dopamine/GABA interaction in striatum and nucleus accumbens of the awake rat. For that, the effects of an increase of the endogenous concentration of glutamate on the extracellular concentration of dopamine and GABA in striatum and nucleus accumbens of young (2-4 months), middle-aged (12-14 months), aged (27-33 months), and very aged (37 months) male Wistar rats were studied. Endogenous extracellular glutamate was selectively increased by perfusing the glutamate uptake inhibitor L-trans-pyrrolidine-3,4-dicarboxylic acid (PDC) through the microdialysis probe. In young rats, PDC (1, 2, and 4 mM) produced a dose-related increase of dialysate concentrations of glutamate in both striatum and nucleus accumbens. PDC also increased dialysate dopamine and GABA in both structures. These increases were significantly correlated with the increases of glutamate but not with the PDC dose used, which strongly suggests that the increases of dopamine and GABA were produced by glutamate. In striatum, there were no significant differences in the dopamine/glutamate and GABA/glutamate correlations between young and aged rats. This means that the effects of glutamate on dopamine and GABA do not change during aging. On the contrary, in the nucleus accumbens of aged rats, the increases of dopamine, when correlated with the increases of glutamate, were significantly lower than in young rats. Moreover, the ratio of dopamine to glutamate increases at maximal increases of glutamate was negatively correlated with aging. On the contrary, the ratio of GABA to glutamate increases in nucleus accumbens was positively correlated with aging, which suggests that the effects of endogenous glutamate on GABA tend to be higher in the nucleus accumbens of aged rats. The findings of this study suggest that aging changes the interaction between endogenous glutamate, dopamine, and GABA in nucleus accumbens, but not in striatum, of the awake rat.     

INTRACELLULAR DIMETHYLSULFOXIDE (DMSO) IN UNICELLULAR MARINE ALGAE: SPECULATIONS ON ITS ORIGIN AND POSSIBLE BIOLOGICAL ROLE

Recent studies have established that aqueous phase concentrations of dimethylsulfoxide (DMSO) often exceed those of dimethylsulfoniopropionate (DMSP) and dimethylsulfide (DMS). Yet, in comparison to DMSP and DMS, DMSO remains a poorly understood component of the marine sulfur cycle. Much of what is known about the mechanisms for the formation and loss for DMSO is inferred from laboratory experiments, and no explanation exists to rationalize how a large pool of DMSO is maintained. One formation pathway that, until very recently, has been ignored involves the direct synthesis of DMSO by marine phytoplankton. This review examines some of the circumstantial evidence for DMSO in marine particulate material and recent reports containing preliminary data for particulate DMSO (DMSO_p) in the marine environment. Drawing on literature from a range of scientific disciplines, speculations on the possible origins and biological functions of intracellular DMSO are also made. On the basis of its physicochemical properties, intracellular DMSO could have a potential role as a cryoprotectant, a specialist cryo-osmoregulator in extreme environments, an intracellular electrolyte modifier, and a free-radical scavenger. The review also assesses the impact of DMSO_p at both the organism and the global level. Consideration is given to the marine biogeochemical cycling of sulfur and potential links to climate control.     

Can habitat characteristics shape vertebral morphology in dolphins? An example of two phylogenetically related species from southern South America

Fast swimming pelagic cetacean species have osteological characteristics that promote a more stable spine in comparison to that of coastal species. The Peale's dolphin (Lagenorhynchus australis) and the hourglass dolphin (Lagenorhynchus cruciger) have a close phylogenetic relationship and are found in coastal and pelagic waters in the Southern Hemisphere, respectively. The aim of this work was to study the relationship between the vertebral column's morphology and its flexibility, across these species of contrasting habitats. Vertebral counts and multiple measurements of each vertebra were used to infer intervertebral flexibility. Bivariate plots and discriminant multivariate analyses were employed to compare each functional region along the vertebral column. Both species displayed a regionalization of the column into three stable regions and two flexible areas, which statistically differ in the proportion of the skeleton occupied in each species. While the Peale's dolphin has rounder vertebrae, associated with higher flexibility, the hourglass dolphin has disk‐shaped vertebrae and strongly inclined processes related to high stability. Although the species are closely related phylogenetically, vertebral morphology is influenced by a diverse set of ecological and behavioral factors, reflecting a high degree of vertebral plasticity within the genus.     

Size–weight relationships of batoids captured by artisanal fishery in the southern Gulf of California,Mexico

This study reports the size–weight relationships (SWR) for nine batoid species that are frequently fished by the artisanal fisheries in the southern Gulf of California. Analysis included a total of 2,012 specimens, caught from October 2013 to July 2016. The slope values (b) oscillated from 2.80 to 3.56. Growth was isometric for five species and positively allometric for four. There were differences in SWR between sexes for three species being in all cases the female greater and heavier than males. This is the first analysis of SWR for the batoid species studied in the Gulf of California.     

Excess mortality in persons with severe mental disorders: a multilevel intervention framework and priorities for clinical practice,policy and research agendas

Excess mortality in persons with severe mental disorders (SMD) is a major public health challenge that warrants action. The number and scope of truly tested interventions in this area remain limited, and strategies for implementation and scaling up of programmes with a strong evidence base are scarce. Furthermore, the majority of available interventions focus on a single or an otherwise limited number of risk factors. Here we present a multilevel model highlighting risk factors for excess mortality in persons with SMD at the individual, health system and socio‐environmental levels. Informed by that model, we describe a comprehensive framework that may be useful for designing, implementing and evaluating interventions and programmes to reduce excess mortality in persons with SMD. This framework includes individual‐focused, health system‐focused, and community level and policy‐focused interventions. Incorporating lessons learned from the multilevel model of risk and the comprehensive intervention framework, we identify priorities for clinical practice, policy and research agendas.     

Interfaces in Perovskite Solar Cells

Rapid improvement in photoconversion efficiency (PCE) of solution processable organometallic hybrid halide based perovskite solar cells (PSCs) have taken the photovoltaic (PV) community with a surprise and has extended their application in other electronic devices such as light emitting diodes, photo detectors and batteries. Together with efforts to push the PCE of PSCs to record values >22% – now at par with that of crystalline silicon solar cells – origin of their PV action and underlying physical processes are also deeply investigated worldwide in diverse device configurations. A typical PSC consists of a perovskite film sandwiched between an electron and a hole selective contact thereby creating ESC/perovskite and perovskite/HSC interfaces, respectively. The selective contacts and their interfaces determine properties of perovskite layer and also control the performance, origin of PV action, open circuit voltage, device stability, and hysteresis in PSCs. Herein, we define ideal charge selective contacts, and provide an overview on how the choice of interfacing materials impacts charge accumulation, transport, transfer/recombination, band‐alignment, and electrical stability in PSCs. We then discuss device related considerations such as morphology of the selective contacts (planar or mesoporous), energetics and electrical properties (insulating and conducting), and its chemical properties (organic vs inorganic). Finally, the outlook highlights key challenges and future directions for a commercially viable perovskite based PV technology.     

An apterous scelionid wasp in mid-Cretaceous Burmese amber (Hymenoptera: Scelionidae)

A remarkably specialized parasitoid wasp of the family Scelionidae (Platygastroidea) is described and figured from mid-Cretaceous (Cenomanian) amber of the Hukawng Valley in northern Myanmar. Geoscelio mckellari Engel and Huang, gen. et sp. nov., is unique for its combination of a compact body, 12 antennal flagellomeres, a 1-2-2 tibial spur formula, a distinct malar sulcus, deeply impressed notauli, complete reduction of the wings, and basal crenulae on the metasomal terga and sterna, among many other features, and is placed within a separate tribe, Geoscelionini Engel and Huang, trib. nov. This is the first flightless species of Platygastroidea known from the Mesozoic, and its affinities with other Mesozoic and extant lineages are discussed.     

Glutamine Synthesis Is Essential for Growth of Streptococcus thermophilus in Milk and Is Linked to Urea Catabolism

Growth of a glutamine synthetase-deficient mutant of Streptococcus thermophilus was compared to that of the parent strain in milk that was not supplemented or was supplemented with ammonium chloride, glutamine, or the urease inhibitor flurofamide. It was concluded that one of the functions of urease is to supply ammonia for the synthesis of glutamine.