Membrane tension-dependent conformational change of Isoleucine 106 of loop B diminishes water permeability in FaPIP2;1.

Aquaporins (AQPs) are membrane proteins specialized in facilitating water transport across membranes. Mechanical stress is one of the various stimuli that regulate AQPs. Briefly, there are several studies that report a decrease in permeability upon an increase in membrane tension.

Quantification of Total Sulfites in Shrimp by BIOFISH 300/3000 SUL Method, Collaborative Study: Final Action 2021.09.

Background: In December 2021, the BIOFISH 300 SUL method for the determination of total sulfites in shrimp was adopted as a First Action Official Method of AnalysisSM by the AOAC INTERNATIONAL.

Objective: A collaborative study was conducted in February 2023 in order to test the reproducibility of the method.

Methods: The method is based on the use of a benchtop biosensor device that relates the concentration of sulfite to a quantifiable electric current signal.

Trapping Charge Mechanism in Hv1 Channels (Hv1).

The majority of voltage-gated ion channels contain a defined voltage-sensing domain and a pore domain composed of highly conserved amino acid residues that confer electrical excitability via electromechanical coupling. In this sense, the voltage-gated proton channel (Hv1) is a unique protein in that voltage-sensing, proton permeation and pH-dependent modulation involve the same structural region. In fact, these processes synergistically work in concert, and it is difficult to separate them.

Lipid fingerprint-based histology accurately classifies nevus, primary melanoma, and metastatic melanoma samples.

Probably, the most important factor for the survival of a melanoma patient is early detection and precise diagnosis. Although in most cases these tasks are readily carried out by pathologists and dermatologists, there are still difficult cases in which no consensus among experts is achieved. To deal with such cases, new methodologies are required.

Design and Implementation of a Prototype Seismogeodetic System for Tectonic Monitoring.

This manuscript describes the design, development, and implementation of a prototype system based on seismogeodetic techniques, consisting of a low-cost MEMS seismometer/accelerometer, a biaxial inclinometer, a multi-frequency GNSS receiver, and a meteorological sensor, installed at the Doñana Biological Station (Huelva, Spain) that transmits multiparameter data in real and/or deferred time to the control center at the University of Cadiz. The main objective of this system is to know, detect, and monitor the tectonic activity in the Gulf of Cadiz region and adjacent areas in which important seismic events occur produced by the interaction of the Eurasian and African plates, in addition to the ability to integrate into a regional early warning system (EWS) to minimize the consequences of dangerous geological phenomena.

N-terminal region is responsible for mHv1 channel activity in MDSCs.

Voltage-gated proton channels (Hv1) are important regulators of the immunosuppressive function of myeloid-derived suppressor cells (MDSCs) in mice and have been proposed as a potential therapeutic target to alleviate dysregulated immunosuppression in tumors. However, till date, there is a lack of evidence regarding the functioning of the Hvcn1 and reports on mHv1 isoform diversity in mice and MDSCs. A computational prediction has suggested that the Hvcn1 gene may express up to six transcript variants, three of which are translated into distinct N-terminal isoforms of mHv1: mHv1.

Size Matters: Free-Energy Calculations of Amino Acid Adsorption over Pristine Graphene.

There is still growing interest in graphene interactions with proteins, both for its possible biological applications and due to concerns over detrimental effects at the cellular level. As with any process involving proteins, an understanding of amino acid composition is desirable. In this work, we systematically studied the adsorption process of amino acids onto pristine graphene via rigorous free-energy calculations.

Quantification of Total Sulfite in Shrimps by BIOFISH 300 SUL Method: First Action 2021.09.

Background: Sulfite is the oldest and most widely used additive in our food supply with antioxidant and preservative properties. Due to its allergenic-like reactions and other adverse health effects, its use is regulated by international regulatory bodies. Therefore, food industries as well as regulatory laboratories must ensure that the maximum concentration of sulfite permitted is not exceeded.

Mechanosensitive aquaporins.

Cellular systems must deal with mechanical forces to satisfy their physiological functions. In this context, proteins with mechanosensitive properties play a crucial role in sensing and responding to environmental changes. The discovery of aquaporins (AQPs) marked a significant breakthrough in the study of water transport.

Protein-Mediated Electroporation in a Cardiac Voltage-Sensing Domain Due to an nsPEF Stimulus.

This study takes a step in understanding the physiological implications of the nanosecond pulsed electric field (nsPEF) by integrating molecular dynamics simulations and machine learning techniques. nsPEF, a state-of-the-art technology, uses high-voltage electric field pulses with a nanosecond duration to modulate cellular activity. This investigation reveals a relatively new and underexplored phenomenon: protein-mediated electroporation.

Role of voltage-gated proton channel (Hv1) in cancer biology.

The acid-base characteristics of tumor cells and the other elements that compose the tumor microenvironment have been topics of scientific interest in oncological research. There is much evidence confirming that pH conditions are maintained by changes in the patterns of expression of certain proton transporters. In the past decade, the voltage-gated proton channel (Hv1) has been added to this list and is increasingly being recognized as a target with onco-therapeutic potential.

Medical Devices with Embedded Sensor Systems: Design and Development Methodology for Start-Ups.

Embedded systems have become a key technology for the evolution of medical devices. However, the regulatory requirements that must be met make designing and developing these devices challenging. As a result, many start-ups attempting to develop medical devices fail.

Quantification of Lactose in Lactose-Free and Low-Lactose Milk and Milk Products by BIOMILK 300/3000 Lac, Collaborative Study: Final Action 2020.09.

Background: In April 2020, the BIOMILK 300 LAC method for the quantification of lactose in lactose-free and low-lactose dairy products was adopted as First Action Official Method of AnalysisSM2020.09 by AOAC INTERNATIONAL. To test the reproducibility of the method, as the last step toward the Final Action status, a collaborative study was organized by BIOLAN Microbiosensores.

In silico approaches to develop new phenyl-pyrimidines as glycogen synthase kinase 3 (GSK-3) inhibitors with halogen-bonding capabilities: 3D-QSAR CoMFA/CoMSIA, molecular docking and molecular dynamics studies.

Glycogen synthase kinase 3 (GSK-3) is involved in different diseases, such as manic-depressive illness, Alzheimer's disease and cancer. Studies have shown that insulin inhibits GSK-3 to keep glycogen synthase active. Inhibiting GSK-3 may have an indirect pro-insulin effect by favouring glycogen synthesis.

Embedded Sensor Systems in Medical Devices: Requisites and Challenges Ahead.

The evolution of technology enables the design of smarter medical devices. Embedded Sensor Systems play an important role, both in monitoring and diagnostic devices for healthcare. The design and development of Embedded Sensor Systems for medical devices are subjected to standards and regulations that will depend on the intended use of the device as well as the used technology.

Aquaporin Gating: A New Twist to Unravel Permeation through Water Channels.

Aquaporins (AQPs) are small transmembrane tetrameric proteins that facilitate water, solute and gas exchange. Their presence has been extensively reported in the biological membranes of almost all living organisms. Although their discovery is much more recent than ion transport systems, different biophysical approaches have contributed to confirm that permeation through each monomer is consistent with closed and open states, introducing the term gating mechanism into the field.

Modification of BIOFISH 300 HIS for Determination of Histamine in Fish and Fish Products: AOAC Performance Tested MethodSM 051604.

Background: The BIOFISH 300 HIS method for the quantification of histamine in fish and fish products was validated by the AOAC Research Institute and granted Performance Tested MethodSM certification in 2016. The method is based on the use of an electrochemical reader (BIOFISH 300 device) together with disposable gold electrodes (Biotest) modified with a specific enzyme that oxidizes the histamine molecules and produces a detectable and quantifiable electric current signal. It was validated for raw fish (tuna, mackerel, sardine, and anchovy), cooked fish (tuna), canned fish (tuna in water, tuna in oil, mackerel in tomato sauce, and pickled sardine), and salted fish (canned salted anchovy).

Spider Toxin SNX-482 Gating Modifier Spontaneously Partitions in the Membrane Guided by Electrostatic Interactions.

Spider toxin SNX-482 is a cysteine-rich peptide that interferes with calcium channel activity by binding to voltage-sensing domains of the Ca2.3 subtype. Two mechanisms dominate the binding process of cysteine-rich peptides: direct binding from the aqueous phase or through lateral diffusion from the membrane, the so-called reduction in dimensionality mechanism.

Mechanism of voltage sensing in Ca- and voltage-activated K (BK) channels.

In neurosecretion, allosteric communication between voltage sensors and Ca binding in BK channels is crucially involved in damping excitatory stimuli. Nevertheless, the voltage-sensing mechanism of BK channels is still under debate. Here, based on gating current measurements, we demonstrate that two arginines in the transmembrane segment S4 (R210 and R213) function as the BK gating charges.

Expression of H1 proton channels in myeloid-derived suppressor cells (MDSC) and its potential role in T cell regulation.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous cell population with high immunosuppressive activity that proliferates in infections, inflammation, and tumor microenvironments. In tumors, MDSC exert immunosuppression mainly by producing reactive oxygen species (ROS), a process triggered by the NADPH oxidase 2 (NOX2) activity. NOX2 is functionally coupled with the Hv1 proton channel in certain immune cells to support sustained free-radical production.

On the effects of induced polarizability at the water-graphene interface classical charge-on-spring models.

Molecular models of the water-graphene interaction are essential to describe graphene in condensed phases. Different challenges are associated with the generation of these models, in particular π-π and dispersion interactions; thus quantum and classical models have been developed and due to the numerical efficiency of the latter, they have been extensively employed. In this work, we have systematically studied, molecular dynamics, two polarizable graphene models, denominated CCCP and CCCPD, employing the charge-on-spring model of the GROMOS forcefield, both being compatible with the polarizable water models COS/G2 and COS/D2, respectively.

Quantification of Lactose in Lactose-Free and Low-Lactose Milk and Milk Products by BIOMILK 300 Lac Biosensor: First Action 2020.09.

Background: In 2018, the AOAC Stakeholder Panel on Strategic Food Analytical Methods approved Standard Method Performance Requirement (SMPR®) 2018.009, for lactose in low-lactose or lactose-free milk, milk products, and products containing dairy ingredients, establishing the minimum recommended performance characteristics to be addressed during the evaluation of methods. Subsequently, AOAC INTERNATIONAL opened a call for methods under the Official Method of AnalysisSM program with the aim of finding a candidate method for confirming compliance with regulatory standards and dispute resolution.

Simulations on Simple Models of Connexin Hemichannels Indicate That Ca Blocking Is Not a Pure Electrostatic Effect.

Connexin hemichannels allow the unspecific but regulated interchange of molecules from ions to second messenger and ATP, between the eukariotic cell and its extracellular space. The transport of ions and water through hemichannels is important for physiological functions and also in the progression of several pathological conditions. Extracellular Ca concentration is one of the regulators that drives the channel to a closed state.

The voltage sensor is responsible for ΔpH dependence in H1 channels.

The dissipation of acute acid loads by the voltage-gated proton channel (H1) relies on regulating the channel's open probability by the voltage and the ΔpH across the membrane (ΔpH = pH - pH). Using monomeric -H1, we asked whether ΔpH-dependent gating is produced during the voltage sensor activation or permeation pathway opening. A leftward shift of the conductance-voltage (G-V) curve was produced at higher ΔpH values in the monomeric channel.

A Drastic Shift in Lipid Adducts in Colon Cancer Detected by MALDI-IMS Exposes Alterations in Specific K Channels.

Even though colorectal cancer (CRC) is one of the most preventable cancers, it is one of the deadliest, and recent data show that the incidence in people <50 years has unexpectedly increased. While new techniques for CRC molecular classification are emerging, no molecular feature is as yet firmly associated with prognosis. Imaging mass spectrometry (IMS) lipidomic analyses have demonstrated the specificity of the lipid fingerprint in differentiating pathological from healthy tissues.