The phosphoinositide PI(3,5)P2 inhibits the activity of plant NHX proton/potassium antiporters: Advantages of a novel electrophysiological approach

In the present work, we discuss the way in which the parallel application of the patch-clamp technique and the 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) fluorescence detection for recording luminal proton changes allows the functional characterization of nonelectrogenic potassium/proton vacuolar antiporters of the NHX (Na+/H+ exchanger) family. Moreover, we review the functional role of the tonoplast-specific phosphoinositide PI(3,5)P2, able to simultaneously inhibit the activity of NHXs and CLC-a transporters, whose coordinated action can play an important role in the water balance of plant cells

Subthalamic neural activity patterns anticipate economic risk decisions in gambling

Economic decision-making is disrupted in individuals with gambling disorder, an addictive behavior observed in Parkinson’s Disease (PD) patients receiving dopaminergic therapy. The subthalamic nucleus (STN) is involved in the inhibition of impulsive behaviors; however its role in impulse control disorders and addiction is still unclear. Here, we recorded STN local field potentials (LFPs) in PD patients with and without gambling disorder during an economic decision-making task. Reaction times analysis showed that for all patients the decision whether to risk preceded task onset. We compared then for both groups the STN LFP preceding high and low risk economic decisions. We found that risk avoidance in gamblers correlated with larger STN LFP low frequency (<12 Hz) fluctuations preceding task onset. In particular, the amplitude of low frequency LFP fluctuations carried significant information about future decisions. Decisions of patients not affected by gambling disorder were instead not correlated with pre-task STN LFP. Our results suggest that STN activity preceding task onset affects risk decisions by pre-emptively inhibiting attraction to high but unlikely rewards in favor of a long-term payoff

Characterization of membrane vesicles in Alteromonas macleodii indicates potential roles in their copiotrophic lifestyle

Bacterial membrane vesicles (MVs) are abundant in the oceans, but their potential functional roles remain unclear. In this study we characterized MV production and protein content of six strains of Alteromonas macleodii, a cosmopolitan marine bacterium. Alteromonas macleodii strains varied in their MV production rates, with some releasing up to 30 MVs per cell per generation. Microscopy imaging revealed heterogenous MV morphologies, including some MVs aggregated within larger membrane structures. Proteomic characterization revealed that A. macleodii MVs are rich in membrane proteins related to iron and phosphate uptake, as well as proteins with potential functions in biofilm formation. Furthermore, MVs harbored ectoenzymes, such as aminopeptidases and alkaline phosphatases, which comprised up to 20% of the total extracellular enzymatic activity. Our results suggest that A. macleodii MVs may support its growth through generation of extracellular ‘hotspots’ that facilitate access to essential substrates. This study provides an important basis to decipher the ecological relevance of MVs in heterotrophic marine bacteria

Decoding Information From Neural Signals Recorded Using Intraneural Electrodes: Toward the Development of a Neurocontrolled Hand Prosthesis

The possibility of controlling dexterous hand prostheses by using a direct connection with the nervous system is particularly interesting for the significant improvement of the quality of life of patients, which can derive from this achievement. Among the various approaches, peripheral nerve based intrafascicular electrodes are excellent neural interface candidates, representing an excellent compromise between high selectivity and relatively low invasiveness. Moreover, this approach has undergone preliminary testing in human volunteers and has shown promise. In this paper, we investigate whether the use of intrafascicular electrodes can be used to decode multiple sensory and motor information channels with the aim to develop a finite state algorithm that may be employed to control neuroprostheses and neurocontrolled hand prostheses. The results achieved both in animal and human experiments show that the combination of multiple sites recordings and advanced signal processing techniques (such as wavelet denoising and spike sorting algorithms) can be used to identify both sensory stimuli (in animal models) and motor commands (in a human volunteer). These findings have interesting implications, which should be investigated in future experiments. © 2006 IEEE

Current Methods to Unravel the Functional Properties of Lysosomal Ion Channels and Transporters

open18siA distinct set of channels and transporters regulates the ion fluxes across the lysosomal membrane. Malfunctioning of these transport proteins and the resulting ionic imbalance is involved in various human diseases, such as lysosomal storage disorders, cancer, as well as metabolic and neurodegenerative diseases. As a consequence, these proteins have stimulated strong interest for their suitability as possible drug targets. A detailed functional characterization of many lysosomal channels and transporters is lacking, mainly due to technical difficulties in applying the standard patch-clamp technique to these small intracellular compartments. In this review, we focus on current methods used to unravel the functional properties of lysosomal ion channels and transporters, stressing their advantages and disadvantages and evaluating their fields of applicability.openFesta M.; Minicozzi V.; Boccaccio A.; Lagostena L.; Gradogna A.; Qi T.; Costa A.; Larisch N.; Hamamoto S.; Pedrazzini E.; Milenkovic S.; Scholz-Starke J.; Ceccarelli M.; Vitale A.; Dietrich P.; Uozumi N.; Gambale F.; Carpaneto A.Festa, M.; Minicozzi, V.; Boccaccio, A.; Lagostena, L.; Gradogna, A.; Qi, T.; Costa, A.; Larisch, N.; Hamamoto, S.; Pedrazzini, E.; Milenkovic, S.; Scholz-Starke, J.; Ceccarelli, M.; Vitale, A.; Dietrich, P.; Uozumi, N.; Gambale, F.; Carpaneto, A

A Novel High-Affinity Sucrose Transporter Is Required for Virulence of the Plant Pathogen Ustilago maydis

A novel, high-affinity sucrose transporter identified in the plasma membrane of the plant pathogen Ustilago maydis is essential for fungal virulence and successful infection of maize

Botulinum Neurotoxin Devoid of Receptor Binding Domain Translocates Active Protease

Clostridium botulinum neurotoxin (BoNT) causes flaccid paralysis by disabling synaptic exocytosis. Intoxication requires the tri-modular protein to undergo conformational changes in response to pH and redox gradients across endosomes, leading to the formation of a protein-conducting channel. The ∼50 kDa light chain (LC) protease is translocated into the cytosol by the ∼100 kDa heavy chain (HC), which consists of two modules: the N-terminal translocation domain (TD) and the C-terminal Receptor Binding Domain (RBD). Here we exploited the BoNT modular design to identify the minimal requirements for channel activity and LC translocation in neurons. Using the combined detection of substrate proteolysis and single-channel currents, we showed that a di-modular protein consisting only of LC and TD was sufficient to translocate active protease into the cytosol of target cells. The RBD is dispensable for cell entry, channel activity, or LC translocation; however, it determined a pH threshold for channel formation. These findings indicate that, in addition to its individual functions, each module acts as a chaperone for the others, working in concert to achieve productive intoxication