A comparative study on recurrent blooms of Alexandrium minutum in two Mediterranean coastal areas

Alexandrium minutum is a toxic dinoflagellate widespread along the Mediterranean coasts. This species is frequently detected year-round at low concentrations within the Mediterranean basin. However, it only proliferates recurrently in some localities. Two affected areas are the Catalan and Sicilian coasts. In order to identify the factors determining the A. minutum blooms in the Mediterranean Sea, we compare the bloom conditions in two harbours: Arenys de Mar (Catalan coast, Spain) and Syracuse (Sicily, Italy), during 2002–2003. Arenys de Mar harbour is a fishing and leisure harbour and receives an input of freshwater rich in nutrients. Likewise, the Syracuse harbour – located on the Ionian coast of Sicily – is subject to freshwater inputs. Some points of this site are used for productive activities such as shellfish farming. A. minutum from the two areas studied were morphologically and genetically identical. In both sites, recurrent blooms take place from winter to spring. Surface water temperatures and salinities during A. minutum bloom events were 12–14.5 °C and 32–38, and 16–24 °C and 32–37.7 for Arenys and Syracuse, respectively. During the blooms, the spatial distribution of A. minutum in the two harbours, the physicochemical characteristics and the phytoplankton community were studied. Similarities in composition of the phytoplankton community were evidenced, with a clear dominance of dinoflagellates over the other taxa. In Arenys, the second dominant species was Prorocentrum micans followed by Scrippsiella spp. and Dinophysis sacculus. The same species were found in Syracuse although P. triestinum, and alternatively Lingulodinium polyedrum, reached cell densities much higher than the other dinoflagellates giving marked water discolourations.     

Yolk hydrolases in the eggs of Anticarsia gemmatalis hubner (Lepidoptera: Noctuidae): A role for inorganic polyphosphate towards yolk mobilization

Despite being the main insect pest on soybean crops in the Americas, very few studies have approached the general biology of the lepidopteran Anticarsia gemmatalis and there is a paucity of studies with embryo formation and yolk mobilization in this species. In the present work, we identified an acid phosphatase activity in the eggs of A. gemmatalis (agAP) that we further characterized by means of biochemistry and cell biology experiments. By testing several candidate substrates, this enzyme proved chiefly active with phosphotyrosine; in vitro assays suggested a link between agAP activity and dephosphorylation of egg yolk phosphotyrosine. We also detected strong activity with endogenous and exogenous short chain polyphosphates (PolyP), which are polymers of phosphate residues involved in a number of physiological processes. Both agAP activity and PolyP were shown to initially concentrate in small vesicles clearly distinct from typically larger yolk granules, suggesting subcellular compartmentalization. As PolyP has been implicated in inhibition of yolk proteases, we performed in vitro enzymatic assays with a cysteine protease to test whether it would be inhibited by PolyP. This cysteine protease is prominent in Anticarsia egg homogenates. Accordingly, short chain PolyP was a potent inhibitor of cysteine protease. We thereby suggest that PolyP hydrolysis by agAP is a triggering mechanism of yolk mobilization in A. gemmatalis.     

Autopresentation of hepatitis B virus envelope antigens by T cells.

Processing and presentation by T cells appear to be limited to antigens that can directly interact with the T-cell surface, thereby overcoming the T-cell inefficiency in antigen capture and internalization. Our study provides evidence that the hepatitis B virus (HBV) envelope proteins can also be efficiently processed and presented by CD4+ and CD8+ T cells to other T cells in a human leukocyte antigen class II-restricted fashion. This phenomenon suggests a receptor-mediated interaction between T cells and the HBV envelope and defines a system that can, we hope, be exploited for the identification of the receptor binding site within the HBV envelope and for the characterization of the putative cellular HBV receptor.     

Call Transmission Efficiency in Native and Invasive Anurans: Competing Hypotheses of Divergence in Acoustic Signals

Invasive species are a leading cause of the current biodiversity decline, and hence examining the major traits favouring invasion is a key and long-standing goal of invasion biology. Despite the prominent role of the advertisement calls in sexual selection and reproduction, very little attention has been paid to the features of acoustic communication of invasive species in nonindigenous habitats and their potential impacts on native species. Here we compare for the first time the transmission efficiency of the advertisement calls of native and invasive species, searching for competitive advantages for acoustic communication and reproduction of introduced taxa, and providing insights into competing hypotheses in evolutionary divergence of acoustic signals: acoustic adaptation vs. morphological constraints. Using sound propagation experiments, we measured the attenuation rates of pure tones (0.2–5 kHz) and playback calls (Lithobates catesbeianus and Pelophylax perezi) across four distances (1, 2, 4, and 8 m) and over two substrates (water and soil) in seven Iberian localities. All factors considered (signal type, distance, substrate, and locality) affected transmission efficiency of acoustic signals, which was maximized with lower frequency sounds, shorter distances, and over water surface. Despite being broadcast in nonindigenous habitats, the advertisement calls of invasive L. catesbeianus were propagated more efficiently than those of the native species, in both aquatic and terrestrial substrates, and in most of the study sites. This implies absence of optimal relationship between native environments and propagation of acoustic signals in anurans, in contrast to what predicted by the acoustic adaptation hypothesis, and it might render these vertebrates particularly vulnerable to intrusion of invasive species producing low frequency signals, such as L. catesbeianus. Our findings suggest that mechanisms optimizing sound transmission in native habitat can play a less significant role than other selective forces or biological constraints in evolutionary design of anuran acoustic signals.     

The influence of building materials on the residual action of BHC

Residual insecticide activity of BHC vapors from various building materials in controlled humidity chambers in the laboratory were significantly different. Laboratory-reared, first instar nymphs of Dipetalogaster maximus were exposed to vapors of BHC which were being released from the treated surfaces of building materials taken from Mambaí, Goiás.     

Involvement of released sphingosine 1-phosphate/sphingosine 1-phosphate receptor axis in skeletal muscle atrophy

Skeletal muscle (SkM) atrophy is caused by several and heterogeneous conditions, such as cancer, neuromuscular disorders and aging. In most types of SkM atrophy overall rates of protein synthesis are suppressed, protein degradation is consistently elevated and atrogenes, such as the ubiquitin ligase Atrogin-1/MAFbx, are up-regulated. The molecular regulators of SkM waste are multiple and only in part known.Sphingolipids represent a class of bioactive molecules capable of modulating the destiny of many cell types, including SkM cells. In particular, we and others have shown that sphingosine 1phosphate (S1P), formed by sphingosine kinase (SphK), is able to act as trophic and morphogenic factor in myoblasts.Here, we report the first evidence that the atrophic phenotype observed in both muscle obtained from mice bearing the C26 adenocarcinoma and C2C12 myotubes treated with dexamethasone was characterized by reduced levels of active phospho-SphK1. The importance of SphK1 activity is also confirmed by the specific pharmacological inhibition of SphK1 able to increase Atrogin-1/MAFbx expression and reduce myotube size and myonuclei number. Furthermore, we found that SkM atrophy was accomplished by significant increase of S1P transporter Spns2 and in changes in the pattern of S1P receptor (S1PRs) subtype expression paralleled by increased Atrogin-1/MAFbx expression, suggesting a role for the released S1P and of specific S1PR-mediated signaling pathways in the control of the ubiquitin ligase. Altogether, these findings provide the first evidence that SphK1/released S1P/S1PR axis acts as a molecular regulator of SkM atrophy, thereby representing a new possible target for therapy in many patho-physiological conditions.     

In vitro and in vivo anti-inflammatory properties of imine resveratrol analogues

Resveratrol is a natural polyphenol found mainly on red grapes and in red wine, pointed as an important anti-inflammatory/immunomodulatory molecule. However, its bioavailability problems have limited its use encouraging the search for new alternatives agents. Thus, in this study, we synthetize 12 resveratrol analogues (6 imines, 1 thioimine and 5 hydrazones) and investigated its cytotoxicity, antioxidant activity and in vitro anti-inflammatory/immunomodulatory properties. The most promising compounds were also evaluated in vivo. The results showed that imines presented less cytotoxicity, were more effective than resveratrol on DPPH scavenger and exhibited an anti-inflammatory profile. Among them, the imines with a radical in the para position, on the ring B, not engaged in an intramolecular hydrogen-interaction, showed more prominent anti-inflammatory activity modulating, in vivo, the edema formation, the inflammatory infiltration and cytokine levels. An immunomodulatory activity also was observed in these molecules. Thus, our results suggest that imines with these characteristics presents potential to control inflammatory disorders.     

Citrate analysis using capillary electrophoresis and complexation with Eu<Superscript>3+</Superscript>-tetracycline

A sensitive assay for citrate was developed. Citrate was incubated with 50 μM Eu³⁺-tetracycline and the complex separated using capillary electrophoresis utilizing post-column laser-induced luminescence detection in a sheath flow cuvette. Signal was linear with citrate concentration from 10 μM to 200 nM. Injection volumes were 320 pL. For the 200 nM sample, this corresponds to the injection of 64 amoles of citrate. Separation time was?<?90 s with a total run time of 5 min. As an application the method was used to analyze citrate in agricultural and medicinal products. The method was also used to develop an assay for the enzyme citrate synthase.     

Efficacy of different interaction devices using non-immersive virtual tasks in individuals with Amyotrophic Lateral Sclerosis: a cross-sectional randomized trial

Background

Amyotrophic Lateral Sclerosis (ALS) is a rapid progressive neurodegenerative disease, characterized by a selective loss of motor neurons, brain stem and spinal cord which leads to deterioration of motor abilities. Devices that promote interaction with tasks on computers can enhance performance and lead to greater independence and utilization of technology.

Objective

To evaluate performance on a computer task in individuals with ALS using three different commonly used non-immersive devices.

Method

Thirty individuals with ALS (18 men and 12 women, mean age 59?years, range 44–74?years) with a mean score of 26, (minimum score of 14 and maximum 41) on the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R) and 30 healthy controls matched for age and gender, participated. All participants were randomly divided into three groups, each using a different device system (motion tracking, finger motion control or touchscreen) to perform three task phases (acquisition, retention and transfer).

Results

Both the ALS and control group (CG) showed better performance on the computer task when using the touchscreen device, but there was limited transfer of performance onto the task performed on the Finger Motion control or motion tracking. However, we found that using the motion tracking device led to transfer of performance to the touchscreen.

Conclusion

This study presents novel and important findings when selecting interaction devices for individuals with ALS to access technology by demonstrating immediate performance benefits of using a touchscreen device, such as improvement of motor skills. There were possible transferable skills obtained when using virtual systems which may allow flexibility and enable individuals to maintain performance overtime.

Trial registration

Registration name: Virtual Task in Amyotrophic Lateral Sclerosis; Registration number: NCT03113630; retrospectively registered on 04/13/2017. Date of enrolment of the first participant to the trial: 02/02/2016.