Signal recognition particle receptor exposes the ribosomal translocon binding site

Signal sequences of secretory and membrane proteins are recognized by the signal recognition particle (SRP) as they emerge from the ribosome. This results in their targeting to the membrane by docking with the SRP receptor, which facilitates transfer of the ribosome to the translocon. Here, we present the 8 angstrom cryo-electron microscopy structure of a "docking complex" consisting of a SRP-bound 80S ribosome and the SRP receptor. Interaction of the SRP receptor with both SRP and the ribosome rearranged the S domain of SRP such that a ribosomal binding site for the translocon, the L23e/L35 site, became exposed, whereas Alu domain-mediated elongation arrest persisted.     

Validation of an immunoturbidimetric D-dimer assay in canine citrated plasma

Abstract: D-dimer is a neoantigen formed when thrombin initiates the transformation of fibrinogen to fibrin; it is derived from plasmin digestion of cross-linked fibrin. In human medicine, the usefulness of this analyte in diagnosing disseminated intravascular coagulation (DIC) has been assessed in patients fulfilling the clinical and laboratory requirements for this disorder. In canine medicine, the use of D-dimer is relatively new. Detailed studies are needed to understand the relationship between D-dimer concentration in plasma and DIC status in dogs. We validated a D-dimer immunoturbidimetric assay (Tina-quant [a] D-Dimer, Boehringer Mannheim) in canine citrated plasma samples. Intra-assay and interassay variability (coefficient of variation) was 5.63% and 8.82%, respectively. The assay was linear, using 2 samples with low and high D-dimer concentrations (r = .996 and .998). Accuracy was 102.2% and 95.7% based on a recovery study in which 2 samples were assessed. Reference values for D-dimer were established using 70 healthy dogs that were assessed clinically and evaluated on the basis of a complete laboratory workup. The reference range was set between 0.02 and 0.28 μg/mL (chi-square test for normal distribution, P > .05).     

Endocrine disruption in a terrestrial isopod under exposure to bisphenol A and vinclozolin

Background, aim, and scope  

In the past decade there has been an increasing awareness about the possible consequences of human and wildlife exposure to endocrine disrupting compounds (EDCs). Bisphenol A (BPA) and vinclozolin (Vz) are EDCs which impacts on vertebrates have been largely investigated. Nevertheless, research on invertebrate effects, especially on soil organisms, are still largely under-represented. This work aims to extend the limited ecotoxicological datasets available and to provide tools to assess the effects of EDCs on the terrestrial species, using Porcellio scaber (Crustacea: Isopoda) as a model organism.     

PrP antibodies do not trigger mouse hippocampal neuron apoptosis

Intraperitoneal administration of ICSM18 and 35, monoclonal antibodies against prion protein (PrP), has been shown to significantly delay the onset of prion disease in mice, and humanized versions are candidate therapeutics for prion and Alzheimer's diseases. However, a previous report of severe and widespread apoptosis after intracerebral injection of anti-PrP monoclonal antibodies raised concerns about such therapy and led to an influential model of prion neurotoxicity via cross-linking of cell surface PrP by disease-related PrP aggregates. In extensive studies including ICSM18 and 35, fully humanized ICSM18, and the previously reported proapoptotic antibodies, we found no evidence of apoptosis, thereby questioning this model of prion neurotoxicity.     

On the diffusion constant of water in wheat

Diffusion-weighted magnetic resonance imaging (MRI) was used to obtain diffusion constants for water in the embryo and endosperm of wheat. Our experiments showed a significant difference between the diffusion constant for the two components. It was also shown that water diffusion in both the endosperm and embryo deviates from the typically observed Gaussian behavior in bulk fluids, showing a time-dependent diffusion constant. Diffusion constants for the embryo and endosperm were shown to differ by an order of magnitude. Using a model for restricted diffusion, information on the endosperm pore size and the embryo cell dimensions could be obtained.     

Synthesis and Antifouling Activity Evaluation of Analogs of Bromosphaerol,a Brominated Diterpene Isolated from the Red Alga Sphaerococcus coronopifolius

Marine biofouling is an epibiotic biological process that affects almost any kind of submerged surface, causing globally significant economic problems mainly for the shipping industry and aquaculture companies, and its prevention so far has been associated with adverse environmental effects for non-target organisms. Previously, we have identified bromosphaerol (1), a brominated diterpene isolated from the red alga Sphaerococcus coronopifolius, as a promising agent with significant antifouling activity, exerting strong anti-settlement activity against larvae of Amphibalanus (Balanus) amphitrite and very low toxicity. The significant antifouling activity and low toxicity of bromosphaerol (1) motivated us to explore its chemistry, aiming to optimize its antifouling potential through the preparation of a number of analogs. Following different synthetic routes, we successfully synthesized 15 structural analogs (2–16) of bromosphaerol (1), decorated with different functional groups. The anti-settlement activity (EC₅₀) and the degree of toxicity (LC₅₀) of the bromosphaerol derivatives were evaluated using cyprids and nauplii of the cirriped crustacean A. amphitrite as a model organism. Derivatives 2, 4, and 6–16 showed diverse levels of antifouling activity. Among them, compounds 9 and 13 can be considered as well-performing antifoulants, exerting their activity through a non-toxic mechanism.     

Proteomic profiling of sea bass muscle by two-dimensional gel electrophoresis and tandem mass spectrometry

In this study, the proteome profile of European sea bass (Dicentrarchus labrax) muscle was analyzed using two-dimensional electrophoresis (2-DE) and tandem mass spectrometry with the aim of providing a more detailed characterization of its specific protein expression profile. A highly populated and well-resolved 2-DE map of the sea bass muscle tissue was generated, and the corresponding protein identity was provided for a total of 49 abundant protein spots. Upon Ingenuity Pathway Analysis, the proteins mapped in the sea bass muscle profile were mostly related to glycolysis and to the muscle myofibril structure, together with other biological activities crucial to fish muscle metabolism and contraction, and therefore to fish locomotor performance. The data presented in this work provide important and novel information on the sea bass muscle tissue-specific protein expression, which can be useful for future studies aimed to improve seafood traceability, food safety/risk management and authentication analysis. This work is also important for understanding the proteome map of the sea bass toward establishing the animal as a potential model for muscular studies.     

Local and remote physical processes driving variability of the planktonic system in the Juan Fernández Archipelago: A multidisciplinary framework providing conservation insights

1. The Juan Fernandez Ridge, a vulnerable marine ecosystem located far off the coast of central Chile and formed by several seamounts, guyots and three islands (Robinson Crusoe, Santa Clara and Alejandro Selkirk), has recently been declared a Coastal Marine Protected Area of Multiple Uses with several National Parks embedded in it.
2. Recent studies have highlighted the influence of remote and local oceanographic structures on the hydrographic dynamics of this ridge. However, there is still a gap in understanding how they affect the structure and dynamics of the surrounding insular planktonic communities.
3. A hydroacoustic and oceanographic survey was conducted during the austral spring (October 2016), including hydrographic and zooplankton sampling around Robinson Crusoe Island. Oceanographic features were identified and tracked using satellite data (chlorophyll-a (Chl-a) and sea surface temperature) and modelling results.
4. Two events of Chl-a increase relative to a threshold (>0.45 mg m⁻³) were forced by different physical processes, both affecting the western side of Robinson Crusoe Island. In event A during the cruise period, Chl-a subsurface maxima were associated with the arrival of a coastal meander originating on the continental shelf off Chile (remote process); the zooplankton was dominated by copepods and salps, with an evident coastal–oceanic gradient. In event B, Chl-a maxima were linked to a local upwelling forced by the intensification of a localized SSW wind. No influence of remote eddies or local Von Kármán vortices on Chl-a distribution was observed.
5. These findings highlight the influence of remote and local physical processes on the structure of planktonic communities around Robinson Crusoe Island. Understanding the variability of these mechanisms and their effects at the base of the pelagic food web is critical in adopting an ecosystem-level approach.

     

Evaluation of different protein sources in fingerling grey mullet <Emphasis Type="Italic">Mugil cephalus</Emphasis> practical diets

An eight-week experiment was carried out to evaluate the effects of different protein sources (fish and haemoglobin meal, soybean meal and torula yeast), in practical diets, on growth, body composition and gut morphology of fingerling grey mullet (Mugil cephalus). Weight gain (%), SGR, FCR, N retention, PER, PGR, FDR and carcass composition of fish were not significantly affected by the dietary protein source. Fish fed the torula yeast based diet showed reduction in growth performance. Histological examinations performed on the alimentary tract of the fish showed a normal structural pattern in the experimental groups, as fundamental histological and histochemical aspects were similar if compared to the control group. The lower growth performance observed in fish fed a torula yeast based diet may be tentatively correlated with the presence of some detrimental morpho-functional aspects in the gut of these fish if compared to fish fed the other diets. Further studies are necessary to confirm this hypothesis.     

Demand feeding and welfare in farmed fish

Following the development of demand-feeding systems, many experiments have been conducted to explore feeding motivation and feed intake in farmed fish. This work aims to review a selection of studies in the field, focusing on three key factors, related to demand feeding and fish welfare. Firstly, we outline how demand feeders should be considered when developing feed management strategies for improving welfare in production conditions. Secondly, via laboratory demand-feeding experiments, we show self-feeding activities depend not only on feeding motivation and social organisation, but also on individual learning capacity and risk-taking behaviour. Thirdly, we report encouraging results demonstrating that when presented with two or more self-feeders containing complementary foods, fish select a diet according to their specific nutritional requirements, suggesting that demand feeders could be used to improve welfare by allowing fish to meet their nutritional needs.