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The Adriatic brook lamprey, Lampetra zanandreai Vladykov 1955, was described from northeastern Italy. Its distribution is thought to include left tributaries of the River Po and the river basins of the Adriatic Sea from the River Po to the River Isonzo/Soča in Italy, Switzerland and Slovenia. It also shows a geographically isolated distribution in the Potenza River on the Adriatic slope in Central Italy. Lampetra from the Neretva River system in Croatia and Bosnia and Herzegovina and the Morača River system in Montenegro that were previously identified as L. zanandreai were recently described as a new species Lampetra soljani Tutman, Freyhof, Dulčić, Glamuzina & Geiger 2017 based on morphological data and a genetic distance between the two species of roughly 2.5% in the DNA barcoding gene cytochrome oxidase I (COI). Since DNA barcodes for L. zanandreai are only available for one population from the upper Po River in northwestern Italy, we generated additional COI nucleotide sequence data of this species from Switzerland, northeastern and central Italy comprising near topotypic material and obtained GenBank sequences of the species from Slovenia to better assess the evolutionary history of the two brook lamprey species in the river basins of the Adriatic Sea. Our data show a low sequence divergence of <1% between L. zanandreai from Switzerland, northeastern and central Italy and Slovenia and the Balkan species L. soljani . However, members of the population previously identified as ' L. zanandreai ' from northwest Italy are genetically highly divergent from those of L. zanandreai and likely belong to an undescribed species, L . sp. 'upper Po'. The presence of a unique and highly divergent brook lamprey lineage in the upper Po River suggests that L. zanandreai and Lampetra sp. 'upper Po' may have evolved in separate paleo drainages during the formation of the modern Po Valley subsequent to marine inundations in the Pliocene., Competing Interests: None declared., (© 2023 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)

A novel ion separation methodology using a cation-exchange membrane modified with iron oxide nanoparticles (Fe 3 O 4 NPs) coated with polyhexamethylene guanidine (PHMG) is proposed. The separation is performed in an electrodialysis cell, where firstly phosphate is electro-adsorbed to the PHMG@Fe 3 O 4 NP coating, followed by a desorption step by applying an electric current.

The interaction of cytochrome c with cardiolipin (CL) is a critical step in the initial stages of apoptosis and is mediated by a positively charged region on the protein surface comprising several lysine residues (site A). Here, the interaction of wt S. cerevisiae cytochrome c (ycc) and its K72A/K73A, K72A/K79A, K73A/K79A and K72A/K73A/K79A variants with CL was studied through UV-Vis and MCD spectroscopies at pH 7 and molecular dynamics (MD) simulations, to clarify the role of the mutated lysines. Moreover, the influence of the lipid to protein ratio on the interaction mechanism was investigated using low (0.5-10) and high (5-60) CL/ycc molar ratios, obtained with small and gradual or large and abrupt CL additions, respectively. Although all proteins bind to CL, switching from the native low-spin His/Met-ligated form to a low-spin bis-His conformer and to a high-spin species at larger CL concentrations, the two schemes of CL addition show relevant differences in the CL/ycc molar ratios at which the various conformers appear, due to differences in the interaction mechanism. Extended lipid anchorage and peripheral binding appear to prevail at low and high CL/ycc molar ratios, respectively. Simultaneous deletion of two or three surface positive charges from Site A does not abolish CL binding, but instead increases protein affinity for CL. MD calculations suggest this unexpected behavior results from the mutation-induced severe weakening of the H-bond connecting the N ε of His26 with the backbone oxygen of Glu44, which lowers the conformational stability compared to the wt species, overcoming the decreased surface electrostatic interaction.

In this study, the preparation of a new, functional anion-exchange membrane (AEM), containing guanidinium groups as the anion-exchanging sites (Gu-100), is described as well as the membrane characterization by XPS, water uptake, permselectivities, and electrical resistances. The functional membrane was also employed in pH-dependent electrodialysis experiments using model dairy wastewater streams. The properties of the new membrane are compared to those of a commercially available anion-exchange membrane bearing conventional quaternary ammonium groups (Gu-0). Guanidinium was chosen for its specific binding properties toward oxyanions: e.g., phosphate. This functional moiety was covalently coupled to an acrylate monomer via a facile two-step synthesis to yield bulk-modified membranes upon polymerization. Significant differences were observed in the electrodialysis experiments for Gu-0 and Gu-100 at pH 7, showing an enhanced phosphate and citrate transport for Gu-100 in comparison to Gu-0. At pH 10 the difference is much more pronounced: for Gu-0 membranes almost no phosphate and citrate transport could be detected, while the Gu-100 membranes transported both ions significantly. We conclude that having guanidinium groups as anion-exchange sites improves the selectivity of AEMs. As the presented monomer synthesis strategy is modular, we consider the implementation of functional groups into a polymer-based membrane via the synthesis of tailor-made monomers as an important step toward selective ion transport, which is relevant for various fields, including water treatment processes and fuel cells.

Recently various porous organic frameworks (POFs, crystalline or amorphous materials) have been discovered, and used for a wide range of applications, including molecular separations and catalysis. Silicon nanowires (SiNWs) have been extensively studied for diverse applications, including as transistors, solar cells, lithium ion batteries and sensors. Here we demonstrate the functionalization of SiNW surfaces with POFs and explore its effect on the electrical sensing properties of SiNW-based devices. The surface modification by POFs was easily achieved by polycondensation on amine-modified SiNWs. Platinum nanoparticles were formed in these POFs by impregnation with chloroplatinic acid followed by chemical reduction. The final hybrid system showed highly enhanced sensitivity for methanol vapour detection. We envisage that the integration of SiNWs with POF selector layers, loaded with different metal nanoparticles will open up new avenues, not only in chemical and biosensing, but also in separations and catalysis.

Neuroglobin (Ngb) is a recently identified hexa-coordinated globin, expressed in the nervous system of humans. Its physiological role is still debated: one hypothesis is that Ngb serves as an electron transfer (ET) species, possibly by reducing cytochrome c and preventing it to initiate the apoptotic cascade. Here, we use the perturbed matrix method (PMM), a mixed quantum mechanics/molecular dynamics approach, to investigate the redox thermodynamics of two neuroglobins, namely the human Ngb and GLB-6 from invertebrate Caenorhabditis elegans. In particular, we calculate the reduction potential of the two globins, resulting in an excellent agreement with the experimental values, and we predict the reorganization energies, λ, which have not been determined experimentally yet. The calculated λ values match well those reported for known ET proteins and thereby support a potential involvement in vivo of the two globins in ET processes.

The voltage-dependent anion channel 1 (VDAC-1) is an important protein of the outer mitochondrial membrane that transports energy metabolites and is involved in apoptosis. The available structures of VDAC proteins show a wide β-stranded barrel pore, with its N-terminal α-helix (N-α) bound to its interior. Electrophysiology experiments revealed that voltage, its polarity, and membrane composition modulate VDAC currents. Experiments with VDAC-1 mutants identified amino acids that regulate the gating process. However, the mechanisms for how these factors regulate VDAC-1, and which changes they trigger in the channel, are still unknown. In this study, molecular dynamics simulations and single-channel experiments of VDAC-1 show agreement for the current-voltage relationships of an "open" channel and they also show several subconducting transient states that are more cation selective in the simulations. We observed voltage-dependent asymmetric distortions of the VDAC-1 barrel and the displacement of particular charged amino acids. We constructed conformational models of the protein voltage response and the pore changes that consistently explain the protein conformations observed at opposite voltage polarities, either in phosphatidylethanolamine or phosphatidylcholine membranes. The submicrosecond VDAC-1 voltage response shows intrinsic structural changes that explain the role of key gating amino acids and support some of the current gating hypotheses. These voltage-dependent protein changes include asymmetric barrel distortion, its interaction with the membrane, and significant displacement of N-α amino acids., (Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.)

A major challenge in nanotechnology is that of determining how to introduce green and sustainable principles when assembling individual nanoscale elements to create working devices. For instance, textile nanofinishing is restricted by the many constraints of traditional pad-dry-cure processes, such as the use of costly chemical precursors to produce nanoparticles (NPs), the high liquid and energy consumption, the production of harmful liquid wastes, and multistep batch operations. By integrating low-cost, scalable, and environmentally benign aerosol processes of the type proposed here into textile nanofinishing, these constraints can be circumvented while leading to a new class of fabrics. The proposed one-step textile nanofinishing process relies on the diffusional deposition of aerosol NPs onto textile fibers. As proof of this concept, we deposit Ag NPs onto a range of textiles and assess their antimicrobial properties for two strains of bacteria (i.e., Staphylococcus aureus and Klebsiella pneumoniae). The measurements show that the logarithmic reduction in bacterial count can get as high as ca. 5.5 (corresponding to a reduction efficiency of 99.96%) when the Ag loading is 1 order of magnitude less (10 ppm; i.e., 10 mg Ag NPs per kg of textile) than that of textiles treated by traditional wet-routes. The antimicrobial activity does not increase in proportion to the Ag content above 10 ppm as a consequence of a "saturation" effect. Such low NP loadings on antimicrobial textiles minimizes the risk to human health (during textile use) and to the ecosystem (after textile disposal), as well as it reduces potential changes in color and texture of the resulting textile products. After three washes, the release of Ag is in the order of 1 wt %, which is comparable to textiles nanofinished with wet routes using binders. Interestingly, the washed textiles exhibit almost no reduction in antimicrobial activity, much as those of as-deposited samples. Considering that a realm of functional textiles can be nanofinished by aerosol NP deposition, our results demonstrate that the proposed approach, which is universal and sustainable, can potentially lead to a wide number of applications.

The rotational spectra of three isotopologues, CH2(35)Cl2···(20)Ne, CH2(35)Cl(37)Cl···(20)Ne, and CH2(35)Cl2···(22)Ne, of the complex dichloromethane-neon have been assigned and measured by molecular beam Fourier transform microwave spectroscopy. The corresponding tunnelling splittings-due to the motion of Ne from above to below the ClCCl plane-have been determined as ΔE0+0- = 6.8900(5), 6.6630(4), and 6.3724(7) MHz, respectively. From these data the barrier to planarity has been obtained, B2 = 68.7 cm(-1). In addition, the structure and the (35)Cl (or (37)Cl) quadrupole coupling constants have been determined.

Perturbed matrix method calculations are performed on a diheme cytochrome c (DHC) protein, in order to assign previously experimentally detemined reduction potentials (E 0 ) to their corresponding heme groups. Very good agreement between calculated values to experimental data prove that the present approach can be used as a predictive tool of redox thermodynamic properties of multicenter redox proteins in the absence of experimental data, or in synergy with state-of-the art spectroscopic and electrochemical approaches to obtain a detailed picture of electron transfer processes within these complex systems.

The K72A/K73H/K79A variant of cytochrome c undergoes a reversible change from a His/Met to a His/His axial heme ligation upon urea-induced unfolding slightly below neutral pH. The unfolded form displays a dramatically lower reduction potential than the folded species along with a pseudo-peroxidase activity. We have studied electrochemically the effects of urea-induced unfolding on the protein electrostatically immobilized on an electrode surface functionalized by means of a negatively charged molecular spacer. The latter mimics the electrostatic interaction with the inner mitochondrial membrane. This behavior has been compared with the unfolding of the same species in solution. This system constitutes a model to decipher the role of the above electrostatic interaction in the unfolding of cytochrome c at physiological pH upon interaction with the membrane component phospholipid cardiolipin in the early stages of the apoptosis cascade. We found that immobilization obstacles protein unfolding due to structural constraints at the interface imposed by protein-SAM interaction.

Many reduced cupredoxins undergo a pH-dependent structural rearrangement, triggered by protonation of the His ligand belonging to the C-terminal hydrophobic loop, usually termed the acid transition. At variance with several members of the cupredoxin family, the acid transition is not observed for azurin (AZ). We have addressed this issue by performing molecular dynamics simulations of AZ and four mutants, in which the C-terminal loop has been replaced with those of other cupredoxins or with polyalanine loops. All of the loop mutants undergo the acid transition in the pH range of 4.4-5.5. The main differences between AZ and its loop mutants are the average value of the active site solvent accessible surface area and the extent of its fluctuations with time, together with an altered structure of the water layer around the copper center. Using functional mode analysis, we found that these variations arise from changes in nonbonding interactions in the second coordination sphere of the copper center, resulting from the loop mutation. Our results strengthen the view that the dynamics at the site relevant for function and its surroundings are crucial for protein activity and for metal-containing electron transferases.

Understanding the factors governing the rate of electron transfer processes in proteins is crucial not only to a deeper understanding of redox processes in living organisms but also for the design of efficient devices featuring biological molecules. Here, molecular dynamics simulations performed on native azurin and four chimeric cupredoxins allow for the calculation of the reorganization energy and of structure-related quantities that were used to clarify the molecular determinants to the dynamics/function relationship in blue copper proteins. We find that the dynamics of the small, metal-binding loop region controls the outer-sphere reorganization energy not only by determining the exposure of the active site to solvent but also through the modulation of the redox-dependent rearrangement of the whole protein scaffold and of the surrounding water molecules.