Dendritic-cell trafficking to lymph nodes through lymphatic vessels

Antigen-presenting dendritic cells often acquire foreign antigens in peripheral tissues such as the skin. Optimal encounter with naive T cells for the presentation of these antigens requires that the dendritic cells migrate to draining lymph nodes through lymphatic vessels. In this article, we review important aspects of what is known about dendritic-cell trafficking into and through lymphatic vessels to lymph nodes. We present these findings in the context of information about lymphatic-vessel biology. Gaining a better understanding of the crosstalk between dendritic cells and lymphatic vessels during the migration of dendritic cells to lymph nodes is essential for future advances in manipulating dendritic-cell migration as a means to fine-tune immune responses in clinical settings.     

Deoxamuscaroneoxime derivatives as useful muscarinic agonists to explore the muscarinic subsite: demox, a modulator of orthosteric and allosteric sites at cardiac muscarinic M2 receptors

A series of muscarinic agonists, straight chained, branched, cyclic alkyl and aromatic derivatives of the oxime 1 (demox) was designed with the aim of investigating their activity on muscarinic receptor subtypes. Effects on M1 receptor were assessed functionally by a microphysiometer apparatus, while M2, M3, and M4 receptor potency and affinity were studied on isolated preparations of guinea pig heart, ileum, and lung, respectively. The results suggest that the substitution of a hydrogen with a long side-chain or bulky group generally induces a decrease in potency at M1 and M3 subtypes, while a general increase in this parameter is obtained at M2 subtype. Among the agonists 2-18, compound 4 behaves as a full agonist with a preference for M3 subtype. Moreover, compound 12 is inactive at M1 and M4 receptors while it displays a full agonist activity at M2 and M3 subtypes. Since demox displays a variable response on cardiac M2 receptors regulating heart force, an in-depth inquiry of the functional behaviour of this compound was carried out at M2 receptors. In presence of 10(-11) and 10(-10) M demox, the binding of [3H]-NMS was increased by approximately 30% as a consequence of an increase of the association of [3H]-NMS to membranes; this effect was not observed in presence of a higher concentration of [3H]-NMS. Higher concentrations of demox decreased the binding of [3H]-NMS to heart atrial membranes but significantly retarded the dissociation of this radioligand. Our results suggest that demox may interact with orthosteric and allosteric sites of atrial M2 muscarinic receptor.     

Rhythms in the ovulatory cycle. 1st: Prolactin. Chronobiological Research Group on Synthetic Peptides in Medicine

Circadian and circatrigintan profiles of prolactin (PRL) in young normally cycling women at 4 well characterized times of the ovulatory cycle have been compared. Circadian patterns of PRL (collected at 2-h intervals for 24h at each phase selected) change during the 4 phases, being higher in the luteal phase. In a consistent percentage of individuals, serum PRL rises notably during the night; in one half of the subjects a peak is located also in the afternoon or early evening. The statistically significant circatrigintan rhythm of PRL shows the acrophase approximately in the mid-luteal phase.     

Are Lipases Still Important Biocatalysts? A Study of Scientific Publications and Patents for Technological Forecasting

The great potential of lipases is known since 1930 when the work of J. B. S. Haldane was published. After eighty-five years of studies and developments, are lipases still important biocatalysts? For answering this question the present work investigated the technological development of four important industrial sectors where lipases are applied: production of detergent formulations; organic synthesis, focusing on kinetic resolution, production of biodiesel, and production of food and feed products. The analysis was made based on research publications and patent applications, working as scientific and technological indicators, respectively. Their evolution, interaction, the major players of each sector and the main subject matters disclosed in patent documents were discussed. Applying the concept of technology life cycle, S-curves were built by plotting cumulative patent data over time to monitor the attractiveness of each technology for investment. The results lead to a conclusion that the use of lipases as biocatalysts is still a relevant topic for the industrial sector, but developments are still needed for lipase biocatalysis to reach its full potential, which are expected to be achieved within the third, and present, wave of biocatalysis.     

Identification of a Probable Pore-Forming Domain in the Multimeric Vacuolar Anion Channel AtALMT9

Aluminum-activated malate transporters (ALMTs) form an important family of anion channels involved in fundamental physiological processes in plants. Because of their importance, the role of ALMTs in plant physiology is studied extensively. In contrast, the structural basis of their functional properties is largely unknown. This lack of information limits the understanding of the functional and physiological differences between ALMTs and their impact on anion transport in plants. This study aimed at investigating the structural organization of the transmembrane domain of the Arabidopsis (Arabidopsis thaliana) vacuolar channel AtALMT9. For that purpose, we performed a large-scale mutagenesis analysis and found two residues that form a salt bridge between the first and second putative transmembrane α-helices (TMα1 and TMα2). Furthermore, using a combination of pharmacological and mutagenesis approaches, we identified citrate as an “open channel blocker” of AtALMT9 and used this tool to examine the inhibition sensitivity of different point mutants of highly conserved amino acid residues. By this means, we found a stretch within the cytosolic moiety of the TMα5 that is a probable pore-forming domain. Moreover, using a citrate-insensitive AtALMT9 mutant and biochemical approaches, we could demonstrate that AtALMT9 forms a multimeric complex that is supposedly composed of four subunits. In summary, our data provide, to our knowledge, the first evidence about the structural organization of an ion channel of the ALMT family. We suggest that AtALMT9 is a tetramer and that the TMα5 domains of the subunits contribute to form the pore of this anion channel.The transport of ions across cellular membranes is mediated by specialized proteins that catalyze the transfer of charged molecules across hydrophobic lipid bilayers. Based on the thermodynamics, two major classes of transport systems can be distinguished: (1) passive transporters such as ion channels, which catalyze the flux of solutes down the electrochemical gradient, and (2) active transporters like pumps and antiporters, which transport molecules against their electrochemical gradient. Independent of the nature of the transport system, the flux of ions across membranes is crucial for a wide range of physiological functions in plants. Among others, ion transport is involved in intracellular pH regulation, metal tolerance, stomatal movement, cellular signaling, plant nutrition, and cell expansion (Roelfsema and Hedrich, 2005; Kim et al., 2010; Barbier-Brygoo et al., 2011). Despite the importance of anion transport in plant physiology, only in the last decade has the molecular identity of anion transport proteins started to be unveiled by identifying the chloride channel (CLC), slow anion channel (SLAC), and aluminum-activated malate transporter (ALMT) families. Their discovery has been a fundamental breakthrough in understanding the molecular mechanisms of anion homeostasis and its roles in various aspects of plant cell physiology (Ward et al., 2009; Barbier-Brygoo et al., 2011; Hedrich, 2012; Martinoia et al., 2012).The CLC family consists of both anion channels and secondary active transporters, which are ubiquitously expressed in all living organisms. In Arabidopsis (Arabidopsis thaliana), the first identified and characterized member of the family was AtCLCa (Hechenberger et al., 1996; Geelen et al., 2000). AtCLCa is targeted to the tonoplast and acts as a 2NO₃⁻/H⁺ antiporter (De Angeli et al., 2006). In planta, AtCLCa represents a major vacuolar nitrate transporter driving the accumulation of this anion into the vacuole. Subsequent studies revealed that all other Arabidopsis CLCs are likewise localized in intracellular membranes but feature different cellular functions (Barbier-Brygoo et al., 2011).The SLAC protein family was identified in the last decade (Negi et al., 2008; Vahisalu et al., 2008). Despite its recent discovery, the characterization of this plant anion transporter family proceeded rapidly (Negi et al., 2008; Vahisalu et al., 2008; Geiger et al., 2009, 2010; Brandt et al., 2012). SLAC1, the first identified member of the family, is involved in slow-type anion currents across the plasma membrane of plant cells (Negi et al., 2008; Vahisalu et al., 2008). This ion channel is expressed in guard cells, where it mediates the efflux of anions into the apoplast, a process that is fundamental for stomata closure. SLAC1 regulates the stomatal aperture in response to different stimuli such as abscisic acid and high CO₂ and ozone concentrations (Negi et al., 2008; Vahisalu et al., 2008). In addition, the activity of SLAC1 is controlled by different kinases (Geiger et al., 2009, 2010) that are part of various signaling pathways. This multiple regulation of SLAC1 suggests that it plays a critical role in the integration of different environmental stimuli.ALMTs are membrane proteins exclusive to plants. In Arabidopsis, this family consists of 14 members that can be grouped into three clades (Kovermann et al., 2007). The first member of the ALMT family, TaALMT1, was identified in wheat (Triticum aestivum) by Sasaki et al. (2004) when screening for genes associated with aluminum resistance. They provided evidence that TaALMT1 as well as AtALMT1, its homolog in Arabidopsis, are channels that catalyze the efflux of malate across the plasma membrane of root cells (Yamaguchi et al., 2005; Hoekenga et al., 2006). This exudation of organic acids into the soil facilitates the detoxification of environmental Al³⁺. Besides contributing to Al³⁺ tolerance, ALMTs have been found to exhibit other important physiological functions. AtALMT12 has been proposed to mediate rapid anion currents across the plasma membrane of guard cells in order to induce stomata closure (Meyer et al., 2010). AtALMT9 and AtALMT6 have been shown to be channels localized in the tonoplast that mediate the export of malate into the vacuole (Kovermann et al., 2007; Meyer et al., 2011). AtALMT6 is predominantly expressed in guard cells, where its activity is regulated by cytosolic Ca²⁺ and vacuolar pH (Meyer et al., 2011). In contrast, AtALMT9 is widely expressed in several plant tissues, such as the mesophyll and guard cells. Recently, AtALMT9 was shown to play a crucial role in stomata movement, where it functions as a malate-activated chloride channel (De Angeli et al., 2013).The knowledge about ion channel structures has expanded considerably in the last 20 years. Notably, various three-dimensional structures of such proteins have been solved (Choe, 2002; Jentsch, 2008; Traynelis et al., 2010). This has boosted the research into and the understanding of structure-function relations in transport systems. Among the anion channel families described above, the structure has been determined for CLCs (Dutzler et al., 2002) and SLACs (Chen et al., 2010). Additionally, large structure-function analyses have been conducted, providing detailed knowledge on the molecular basis underlying the ion channel functionality of these families. In contrast, little information was revealed about the structure of ALMTs by describing an important phosphorylation site (Ligaba et al., 2009; Furuichi et al., 2010) and by providing data on the topology (Motoda et al., 2007; Dreyer et al., 2012). However, the proposed models in these studies do not entirely coincide regarding the number of transmembrane-spanning domains, the cellular orientation of the N terminus, and the organization of the C-terminal domain. Therefore, the structural organization of ALMTs is still ambiguous.In this study, we performed a large-scale mutagenesis analysis of the transmembrane domain (TMD) of Arabidopsis ALMTs using the vacuolar channel AtALMT9 as a model. The aim was to identify regions of the TMD that potentially exhibit functional relevance by forming the pore or the voltage sensor. For that purpose, we took advantage of citrate, which we identified as an open channel blocker of AtALMT9. The use of this blocker allowed elucidation of the structural details of ion channels, such as the quaternary organization and pore-forming domains, when no crystal structure was available (MacKinnon, 1991; Yellen et al., 1991; Ferrer-Montiel and Montal, 1996; Linsdell, 2005). By this means, it is possible to show, for instance, that potassium channels are tetramers and to identify their “selectivity filter” domain (MacKinnon and Yellen, 1990; MacKinnon, 1991). Thus, by using citrate, we pharmacologically investigated structure-function relations in AtALMT9. We identified a region adjacent to and within the fifth putative TMD that is supposedly involved in forming the permeation pathway of AtALMT9. Moreover, we demonstrated that AtALMT9 is a multimeric channel of probably four subunits in which the monomers participate in forming the pore.     

Motivational Modulation of Self-Initiated and Externally Triggered Movement Speed Induced by Threat of Shock: Experimental Evidence for Paradoxical Kinesis in Parkinson’s Disease

Background

Paradoxical kinesis has been observed in bradykinetic people with Parkinson’s disease. Paradoxical kinesis occurs in situations where an individual is strongly motivated or influenced by relevant external cues. Our aim was to induce paradoxical kinesis in the laboratory. We tested whether the motivation of avoiding a mild electric shock was sufficient to induce paradoxical kinesis in externally-triggered and self-initiated conditions in people with Parkinson’s disease tested on medication and in age-matched controls.

Methods

Participants completed a shock avoidance behavioural paradigm in which half of the trials could result in a mild electric shock if the participant did not move fast enough. Half of the trials of each type were self-initiated and half were externally-triggered. The criterion for avoiding shock was a maximum movement time, adjusted according to each participant’s performance on previous trials using a staircase tracking procedure.

Results

On trials with threat of shock, both patients with Parkinson’s disease and controls had faster movement times compared to no potential shock trials, in both self-initiated and externally-triggered conditions. The magnitude of improvement of movement time from no potential shock to potential shock trials was positively correlated with anxiety ratings.

Conclusions

When motivated to avoid mild electric shock, patients with Parkinson’s disease, similar to healthy controls, showed significant speeding of movement execution. This was observed in both self-initiated and externally-triggered versions of the task. Nevertheless, in the ET condition the improvement of reaction times induced by motivation to avoid shocks was greater for the PD patients than controls, highlighting the value of external cues for movement initiation in PD patients. The magnitude of improvement from the no potential shock to the potential shock trials was associated with the threat-induced anxiety. This demonstration of paradoxical kinesis in the laboratory under both self-initiated and externally-triggered conditions has implications for motivational and attentional enhancement of movement speed in Parkinson’s disease.     

Does the temperature sensitivity of decomposition of soil organic matter depend upon water content,soil horizon,or incubation time?

Several studies have shown multiple confounding factors influencing soil respiration in the field, which often hampers a correct separation and interpretation of the different environmental effects on respiration. Here, we present a controlled laboratory experiment on undisturbed organic and mineral soil cores separating the effects of temperature, drying–rewetting and decomposition dynamics on soil respiration. Specifically, we address the following questions:

• 1 Is the temperature sensitivity of soil respiration (Q₁₀) dependent on soil moisture or soil organic matter age (incubation time) and does it differ for organic and mineral soil as suggested by recent field studies.
• 2 How much do organic and mineral soil layers contribute to total soil respiration?
• 3 Is there potential to improve soil flux models of soil introducing a multilayer source model for soil respiration?

Eight organic soil and eight mineral soil cores were taken from a Norway spruce (Picea abies) stand in southern Germany, and incubated for 90 days in a climate chamber with a diurnal temperature regime between 7 and 23°C. Half of the samples were rewetted daily, while the other half were left to dry and rewetted thereafter. Soil respiration was measured with a continuously operating open dynamic soil respiration chamber system. The Q₁₀ was stable at around 2.7, independent of soil horizon and incubation time, decreasing only slightly when the soil dried. We suggest that recent findings of the Q₁₀ dependency on several factors are emergent properties at the ecosystem level, that should be analysed further e.g. with regard to rhizosphere effects. Most of the soil CO₂ efflux was released from the organic samples. Initially, it averaged 4.0 μmol m^?2 s^?1 and declined to 1.8 μmol m^?2 s^?1 at the end of the experiment. In terms of the third question, we show that models using only one temperature as predictor of soil respiration fail to explain more than 80% of the diurnal variability, are biased with a hysteresis effect, and slightly underestimate the temperature sensitivity of respiration. In contrast, consistently more than 95% of the diurnal variability is explained by a dual‐source model, with one CO₂ source related to the surface temperature and another CO₂ source related to the central temperature, highlighting the role of soil surface processes for ecosystem carbon balances.     

Control of Lobesia botrana (Lepidoptera: Tortricidae) by biodegradable ecodian sex pheromone dispensers

Mating disruption with a high density of sex pheromone dispensers is a new strategy recently developed for the control of the moth Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae). Ecodian LB dispensers, made of low-cost biodegradable material, were formulated with 10 mg of (E,Z) -7,9-dodecadienyl acetate and placed at a rate of 1,600 dispensers per ha. Seasonal dispenser performances were studied using different methods. The female attractiveness disruption and the efficacy of the method were evaluated in the field. The release rates of field-aged Ecodian LB dispensers, measured directly by solid phase microextraction, was comparable with that of the standard monitoring lure after 50-60 d of field exposure and significantly lower beyond 60 d; however, at the end of the season, it was approximately 46 times higher than that of a calling L. botrana female. Electroantennographic recordings showed that dispensers of different field age strongly stimulated male antennae. In a wind tunnel test, dispensers elicited close-range approaches and direct source contacts irrespective of their age. In fields treated with Ecodian dispensers the attractiveness of traps lured with calling females and monitoring baits was significantly reduced. Our data suggest that Ecodian dispensers are active sources of pheromone throughout the season. The efficacy of Ecodian strategy for L. botrana control was comparable with standard mating disruption and curative insecticides.     

The role of the coypu (Myocastor coypus), an invasive aquatic rodent species,in the epidemiological cycle of leptospirosis: a study in two wetlands in the East of France

Leptospirosis is caused by pathogenic species of the Leptospira genus. Animals can have two roles in the epidemiological cycle: they can be an accidental host and suffer of the disease or a reservoir host which does not express any clinical sign and shed bacteria in their urine. Some of the most known reservoirs for leptospirosis are certain rodent species, but the situation is less clear for aquatic rodents, especially for coypu (Myocastor coypus). It has been shown that this species can have kidney carriage for leptospirosis, but the relationship between carriage and individuals or population health has not been investigated yet. We trapped 133 coypus in two wetlands in the East of France during 3 years. For each animal, a complete necropsy, leptospirosis serology, and a specific real-time quantitative PCR (qPCR) for pathogenic leptospires were performed; in addition, for some animals, a specific kidney culture for leptospires and histology on kidney were performed. In spite of a high seroprevalence (respectively 76 % and 64 %) and of a significant prevalence of kidney carriage in both areas (respectively 12.1 % and 8.0 % of positive qPCR on kidney), the trapped animals seemed in good health, and the population did not seem to be affected by the circulation of the bacteria. These findings are concurring arguments to consider coypu as a real reservoir for leptospirosis.