Cholinergic interneurons control local circuit activity and cocaine conditioning

Cholinergic neurons are widespread, and pharmacological modulation of acetylcholine receptors affects numerous brain processes, but such modulation entails side effects due to limitations in specificity for receptor type and target cell. As a result, causal roles of cholinergic neurons in circuits have been unclear. We integrated optogenetics, freely moving mammalian behavior, in vivo electrophysiology, and slice physiology to probe the cholinergic interneurons of the nucleus accumbens by direct excitation or inhibition. Despite representing less than 1% of local neurons, these cholinergic cells have dominant control roles, exerting powerful modulation of circuit activity. Furthermore, these neurons could be activated by cocaine, and silencing this drug-induced activity during cocaine exposure (despite the fact that the manipulation of the cholinergic interneurons was not aversive by itself) blocked cocaine conditioning in freely moving mammals.     

Integrated study of benthic foraging resources for Atlantic walrus (Odobenus rosmarus rosmarus) in the Pechora Sea,south-eastern Barents Sea

1. The Atlantic walrus, Odobenus rosmarus rosmarus, forms a herd of nearly 4,000 heads in the Pechora Sea (south-eastern Barents Sea). The Near Threatened status of O. rosmarus rosmarus and the relative isolation of the Pechora Sea population, as well as the potential impacts of human activities in the area, make it important to characterize key habitats, including feeding grounds, in order to protect the species.
2. The aim of the present study was to integrate multiple sources of environmental and biological data collected by satellite telemetry, remotely operated vehicle (ROV), and benthic grab sampling to examine the distribution and diversity of benthic foraging resources used by walrus in the Pechora Sea.
3. Analysis of satellite telemetry data from seven males tagged on Vaigach Island helped to identify areas of high use by walruses near haulout sites on Matveev and Vaigach islands, and in between. Field data were collected from those feeding grounds in July 2016 using ROV video recordings and bottom grab sampling. Analysis of 19 grab stations revealed a heterogeneous macrobenthic community of 133 taxa with a mean biomass of 147.11 ± 7.35 g/m². Bivalve molluscs, particularly Astarte borealis, Astarte montagui, and Ciliatocardium ciliatum, dominated the overall macrobenthic biomass, making up two-thirds of the total.
4. Analysis of 16 ROV video transects showed high occurrences of mobile benthic decapods (3.03 ± 2.74 ind./min) and provided the first direct evidence that areas actively used by walrus in the Pechora Sea overlap with the distribution of the non-native omnivorous snow crab, Chionoecetes opilio.
5. Integrating multiple data sources provides an early foundation for the kinds of ecosystem-based approaches needed to improve Pechora Sea resource management and to underpin Russia’s nascent marine spatial planning initiatives. Factors that need to be considered in marine spatial planning include impacts on benthic feeding grounds from offshore oil and gas development and the spread of the snow crab.

     

A Collagen Basketweave from the Giant Squid Mantle as a Robust Scaffold for Tissue Engineering

The growing applications of tissue engineering technologies warrant the search and development of biocompatible materials with an appropriate strength and elastic moduli. Here, we have extensively studied a collagenous membrane (GSCM) separated from the mantle of the Giant squid Dosidicus Gigas in order to test its potential applicability in regenerative medicine. To establish the composition and structure of the studied material, we analyzed the GSCM by a variety of techniques, including amino acid analysis, SDS-PAGE, and FTIR. It has been shown that collagen is a main component of the GSCM. The morphology study by different microscopic techniques from nano- to microscale revealed a peculiar packing of collagen fibers forming laminae oriented at 60–90 degrees in respect to each other, which, in turn, formed layers with the thickness of several microns (a basketweave motif). The macro- and micromechanical studies showed high values of the Young’s modulus and tensile strength. No significant cytotoxicity of the studied material was found by the cytotoxicity assay. Thus, the GSCM consists of a reinforced collagen network, has high mechanical characteristics, and is non-toxic, which makes it a good candidate for the creation of a scaffold material for tissue engineering.     

Operating model design in tuna Regional Fishery Management Organizations: Current practice,issues and implications

The five Regional Fishery Management Organizations dedicated to tunas (tRFMOs) are all either developing or implementing Management Strategy Evaluations (MSEs) to provide advice for the stocks under their competencies. Providing a comparative overview will help tRFMOs to learn from one another and to collaborate on common solutions and may also help to more clearly define the challenges of building decision support tools in contexts of large scientific uncertainty and where management requires cooperation across multiple stakeholders characterized by unequal power and divergent interests. For example, our overview showed that in most cases, a grid‐based design with an emphasis on structural uncertainty has been adopted. However, uncertainties such as sampling errors and non‐stationarity of important ecological processes, which are of potentially equal significance for demonstrating robustness of management procedures, were not considered. This paper identifies key issues for operating model (OM) design that challenges the tRFMOs, compares how these challenges are being met, summarizes what lessons have been learned and suggests a way forward. Although the current approach of using assessment models as the basis for OM design is a reasonable starting point, improvements should be made to the conditioning of OMs, especially with respect to enabling the inclusion of other important processes and uncertainties that are difficult to account for in stock assessments but that can crucially affect the robustness of advice. Attempts should also be made to improve documentation and communication of uncertainties that are included and those that are excluded from consideration in the process.     

Oily waste containing natural radionuclides: does it cause stimulation or inhibition of soil bacterial community?

Contamination with oily wastes containing natural radionuclides is a potential hazard for soil health and function. Our study aimed to reveal both structural and functional changes of the microbial community resistant to and able to decompose oily wastes in soil. To do this, we determined CO₂ efflux, microbial biomass (by the extraction‐fumigation method), and community structure (by PCR‐SSCP) for 120 d after application of radioactive oily wastes to the soil at the ratio 1:4. The addition of the waste resulted in an increase of the activity concentration of ²²⁶Ra by 130 times (up to 643 Bq kg^?1) and of ²³²Th by 29 times (up to 254 Bq kg^?1). The calculated weighted dose for the radionuclide ²²⁶Ra was found to be below the values that are known to affect microorganisms. However, the cumulative effect of a repeated deposition of radioactive oily waste may result in an increase of the weighted dose up to an effective level. During the incubation, the hydrocarbon (HC) content of the waste‐treated soil decreased from 156 to 54 g kg^?1 of soil indicating intensive decomposition of added organics by soil microorganisms. The waste application, however, led to an inhibition of soil microbial biomass compared with the control (by 26–47%). Microbial respiration was stimulated in the first month of incubation and then decreased until the end of the incubation period (by up to 74% compared to the control). The qCO₂ was estimated to be 3‐fold higher than the control on day 1 of incubation and equal to the control on day 120 of incubation. The bacterial diversity decreased in the contaminated soil compared with the control soil. The bacterial community structure was altered by domination of new oil degrader species belonging to the genera Dyella, Pseudoxanthomonas, Sinobacter, and Parvibaculum. Thus, disposal of radioactive petroleum waste strongly altered the structure of the microbial community resulting in the selection of resistant species able to decompose pollutants and also affected the community function (inhibition of microbial biomass and stimulation of respiration) which tended to stabilize after long‐term incubation.