Is African non-annual killifish Fundulopanchax gardneri (Teleostei; Cyprinodontiformes; Nothobranchiidae) true non-annual?

BACKGROUND: Annual or seasonal killifishes (Cyprinodontiformes: Nothobranchiidae) are unique among fish in their ability to enter into developmental arrests (diapauses: DI, DII, and DIII). They have a short lifespan and their embryos are exceptionally tolerant to a variety of environmental stresses. These traits make them a popular model for studying vertebrate diapause, aging, stress tolerance, genome adaptation, and evolution. In such issues, in a comparative evolutionary framework, Fundulopanchax gardneri, a popular aquarium fish from Africa, is commonly used as a representative non-annual model though its development is not studied in detail and whether it includes diapauses remains uncertain. RESULTS: We described in detail for the first time embryonic development of F. gardneri and revealed it to resemble that in the undoubtedly annual Austrofundulus limnaeus killifish in displaying two developmental depressions. However, if compared with A. limnaeus, these developmental states look like "less intense" versions of DII and DIII rather than true diapauses. CONCLUSIONS: To determine whether developmental depressions in F. gardneri represent "true" diapauses or only their functional equivalents, detailed studies of embryonic development of different killifish both annual and non-annual are needed. Before that, acceptance of F. gardneri as a representative non-annual fish seems premature.

Skull development in the Iberian newt, Pleurodeles waltl (Salamandridae: Caudata: Amphibia): timing, sequence, variations, and thyroid hormone mediation of bone appearance.

The cranial ossification sequence in Pleurodeles waltl is widely used in phylogenetic analyses of amphibian origin and evolution. However, the patterns published to date are far from completely resolved and contain certain discrepancies. Based on a large sample of P. waltl specimens ranging from early post-hatching larvae to post-metamorphic newts, we determined the most common cranial ossification sequence and revealed its intraspecific variations. Since thyroid hormones (THs) are involved in the mediation of skull development in salamanders, we studied the role of THs in the cranial development of P. waltl. The normal sequence and timing of bone appearance were compared with those in larvae reared under conditions of high (in 1 and 2 ng mL-1 triiodothyronine) and low [in 0.02% thiourea (TU), which inhibits thyroid gland activity] TH levels. Metamorphosis was greatly accelerated in the TH-treated larvae and was arrested in the TU-treated larvae, which retained the larval pattern of the palate and rudimentary external gills even after 2 years of the experiment. Early-appearing bones (the coronoid, vomer, palatine, dentary, squamosal, premaxilla, parasphenoid, pterygoid, prearticular, vomer, frontal, parietal, exoccipital, in this order) arise at the same stages and ages, and follow the same ossification sequence under different TH levels. The timing of the appearance of bones normally arising in the late larval and metamorphic periods (the quadratojugal, orbitosphenoid, prootic, maxilla, nasal, os thyroideum, prefrontal, quadrate, in this order) changes depending on the TH level. The maxilla and nasal display the most pronounced reaction to changes in the TH level: they appear precociously in TH-treated animals, while their appearance is postponed and they remain rudimentary in TU-treated animals. Because of different responses to THs, the order in which late-arising bones appear changes depending on the TH level. Although bones appearing early in larval ontogeny (e.g. the premaxilla, vomer, squamosal, palatine) display no TH-induced reaction when they start to develop, their further differentiation shows dependence on THs, and these bones become TH-inducible closer to metamorphosis. These findings indicate that TH involvement in the mediation of cranial development changes from minimal (if at all) in its early stages to maximal during metamorphosis. It is likely that the appearance of bones early in development is mediated by factors other than THs. Their further development is accompanied by changes in the mechanisms mediating their morphological differentiation. That is, likely non-hormonal mediation becomes replaced or/and complemented by hormonal mediation. The constituent parts of the same bone may exhibit differences in their reactions to changes in TH levels. Although in normal development, the overall cranial ossification sequence is constant, there was variation in the order in which late-appearing bones was recorded. These observations suggest that this variation results from individual variability in the internal TH level. Comparison with other salamanders suggests that (a) the pattern of TH mediation described in P. waltl is common for cranial development of metamorphosing urodeles and (b) the same bone may differ in its TH dependence in different salamanders, e.g. there are interspecific variations in the degree of TH dependence of individual cranial bones.

Symmetry Effects in Photoinduced Electron Transfer in Chlorin-Quinone Dyads: Adiabatic Suppression in the Marcus Inverted Region.

In donor-acceptor dyads undergoing photoinduced electron transfer (PET), a direction or pathway for electron movement is usually dictated by the redox properties and the separation distance between the donor and acceptor subunits, while the effect of symmetry is less recognized. We have designed and synthesized two isomeric donor-acceptor assemblies in which electronic coupling between donor and acceptor is altered by the orbital symmetry control with the reorganization energy and charge transfer exothermicity being kept unchanged. Analysis of the optical absorption and luminescence spectra, supported by the DFT and TD-DFT calculations, showed that PET in these assemblies corresponds to the Marcus inverted region (MIR) and has larger rate for isomer with weaker electronic coupling. This surprising observation provides the first experimental evidence for theoretically predicted adiabatic suppression of PET in MIR, which unambiguously controlled solely by symmetry.

Evolutionary selection growth of two-dimensional materials on polycrystalline substrates.

There is a demand for the manufacture of two-dimensional (2D) materials with high-quality single crystals of large size. Usually, epitaxial growth is considered the method of choice 1 in preparing single-crystalline thin films, but it requires single-crystal substrates for deposition. Here we present a different approach and report the synthesis of single-crystal-like monolayer graphene films on polycrystalline substrates. The technological realization of the proposed method resembles the Czochralski process and is based on the evolutionary selection 2 approach, which is now realized in 2D geometry. The method relies on 'self-selection' of the fastest-growing domain orientation, which eventually overwhelms the slower-growing domains and yields a single-crystal continuous 2D film. Here we have used it to synthesize foot-long graphene films at rates up to 2.5 cm h-1 that possess the quality of a single crystal. We anticipate that the proposed approach could be readily adopted for the synthesis of other 2D materials and heterostructures.

The membrane trafficking and functionality of the K+-Cl- co-transporter KCC2 is regulated by TGF-ß2.

Functional activation of the neuronal K(+)-Cl(-) co-transporter KCC2 (also known as SLC12A5) is a prerequisite for shifting GABAA responses from depolarizing to hyperpolarizing during development. Here, we introduce transforming growth factor ß2 (TGF-ß2) as a new regulator of KCC2 membrane trafficking and functional activation. TGF-ß2 controls membrane trafficking, surface expression and activity of KCC2 in developing and mature mouse primary hippocampal neurons, as determined by immunoblotting, immunofluorescence, biotinylation of surface proteins and KCC2-mediated Cl(-) extrusion. We also identify the signaling pathway from TGF-ß2 to cAMP-response-element-binding protein (CREB) and Ras-associated binding protein 11b (Rab11b) as the underlying mechanism for TGF-ß2-mediated KCC2 trafficking and functional activation. TGF-ß2 increases colocalization and interaction of KCC2 with Rab11b, as determined by 3D stimulated emission depletion (STED) microscopy and co-immunoprecipitation, respectively, induces CREB phosphorylation, and enhances Rab11b gene expression. Loss of function of either CREB1 or Rab11b suppressed TGF-ß2-dependent KCC2 trafficking, surface expression and functionality. Thus, TGF-ß2 is a new regulatory factor for KCC2 functional activation and membrane trafficking, and a putative indispensable molecular determinant for the developmental shift of GABAergic transmission.

Anisotropic Etching of Hexagonal Boron Nitride and Graphene: Question of Edge Terminations.

Chemical vapor deposition (CVD) has been established as the most effective way to grow large area two-dimensional materials. Direct study of the etching process can reveal subtleties of this competing with the growth reaction and thus provide the necessary details of the overall growth mechanism. Here we investigate hydrogen-induced etching of hBN and graphene and compare the results with the classical kinetic Wulff construction model. Formation of the anisotropically etched holes in the center of hBN and graphene single crystals was observed along with the changes in the crystals' circumference. We show that the edges of triangular holes in hBN crystals formed at regular etching conditions are parallel to B-terminated zigzags, opposite to the N-terminated zigzag edges of hBN triangular crystals. The morphology of the etched hBN holes is affected by a disbalance of the B/N ratio upon etching and can be shifted toward the anticipated from the Wulff model N-terminated zigzag by etching in a nitrogen buffer gas instead of a typical argon. For graphene, etched hexagonal holes are terminated by zigzag, while the crystal circumference is gradually changing from a pure zigzag to a slanted angle resulting in dodecagons.

Interactions between ICAM-5 and ß1 integrins regulate neuronal synapse formation.

Intercellular adhesion molecule-5 (ICAM-5) is a dendrite-specific adhesion molecule, which functions in both the immune and nervous systems. ICAM-5 is the only negative regulator that has been identified for maturation of dendritic spines so far. Shedding of the ICAM-5 ectodomain promotes spine maturation and enhances synaptic activity. However, the mechanism by which ICAM-5 regulates spine development remains poorly understood. In this study, we found that ablation of ICAM5 expression resulted in a significant increase in the formation of synaptic contacts and the frequency of miniature excitatory post-synaptic currents, an indicator of pre-synaptic release probability. Antibodies against ICAM-5 and ß1 integrins altered spine maturation. Furthermore, we found that ß1 integrins serve as binding partners for ICAM-5. ß1 integrins were immunoprecipitated with ICAM-5 from mouse brain and the binding region in ICAM-5 was localized to the two first Ig domains. ß1 integrins were juxtaposed to filopodia tips at the early stage of synaptic formation, but as synapses matured, ß1 integrins covered the mushroom spines. Loss of ß1 integrins from the pre-synaptic sites affected the morphology of the post-synaptic structures. ICAM-5 ectodomain cleavage decreased or increased when the interaction between ICAM-5 and ß1 integrins was potentiated or weakened, respectively, using antibodies. These results suggest that the interaction between ICAM-5 and ß1 integrins is important in formation of functional synapses.

Recent advances on CAR-T signaling pave the way for prolonged persistence and new modalities in clinic.

Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of hematological malignancies. The importance of the receptor costimulatory domain for long-term CAR-T cell engraftment and therapeutic efficacy was demonstrated with second-generation CAR-T cells. Fifth generation CAR-T cells are currently in preclinical trials. At the same time, the processes that orchestrate the activation and differentiation of CAR-T cells into a specific phenotype that predisposes them to long-term persistence are not fully understood. This review highlights ongoing research aimed at elucidating the role of CAR domains and T-cell signaling molecules involved in these processes.

Improved Characterization of Aqueous Single-Walled Carbon Nanotube Dispersions Using Dynamic Light Scattering and Analytical Centrifuge Methods.

Aqueous dispersions of single-walled carbon nanotubes (SWCNTs) with a surfactant were studied by using a combination of differential sedimentation and dynamic light scattering methods. When applied to elongated particles like SWCNTs, the differential sedimentation method makes it possible to measure their diameters in dispersions, while the dynamic light scattering method allows to measure their lengths. Both methods have logarithmic dependence on the ratio between the length and diameter of the particles, and their simultaneous use improves the accuracy of measuring particles' dimensions. It was shown that sonication of dispersions leads not only to unbundling of agglomerates into individual nanotubes but also to a decrease in their lengths and the appearance of new defects detectable in increasing the D/G ratio in the Raman spectra. Unbundling into individual nanotubes occurs after exposure to 1 kWh/L energy density, and the single nanotube diameter with SDBS is ca. 3.3 nm larger than that of the naked nanotubes. Conductivity of thin SWCNT films made out of individual nanotubes demonstrates a power law dependence with the exponent close to the theoretical one for rigid rods.

Hydrogen bond geometries and proton tautomerism of homoconjugated anions of carboxylic acids studied via H/D isotope effects on 13C NMR chemical shifts.

Ten formally symmetric anionic OHO hydrogen bonded complexes, modeling Asp/Glu amino acid side chain interactions in nonaqueous environment (CDF(3)/CDF(2)Cl solution, 200-110 K) have been studied by (1)H, (2)H, and (13)C NMR spectroscopy, i.e. intermolecularly H-bonded homoconjugated anions of acetic, chloroacetic, dichloroacetic, trifluoroacetic, trimethylacetic, and isobutyric acids, and intramolecularly H-bonded hydrogen succinate, hydrogen rac-dimethylsuccinate, hydrogen maleate, and hydrogen phthalate. In particular, primary H/D isotope effects on the hydrogen bond proton signals as well as secondary H/D isotope effects on the (13)C signals of the carboxylic groups are reported and analyzed. We demonstrate that in most of the studied systems there is a degenerate proton tautomerism between O-H···O(-) and O(-)···H-O structures which is fast in the NMR time scale. The stronger is the proton donating ability of the acid, the shorter and more symmetric are the H-bonds in each tautomer of the homoconjugate. For the maleate and phthalate anions exhibiting intramolecular hydrogen bonds, evidence for symmetric single well potentials is obtained. We propose a correlation between H/D isotope effects on carboxylic carbon chemical shifts and the proton transfer coordinate, q(1) = ½(r(OH) - r(HO)), which allows us to estimate the desired OHO hydrogen bond geometries from the observed (13)C NMR parameters, taking into account the degenerate proton tautomerism.

Allium pallasii and A. caricifolium-Surprisingly Diverse Old Steppe Species, Showing a Clear Geographical Barrier in the Area of Lake Zaysan.

Polymorph Allium pallasii s.l. from monotypic A. sect. Pallasia was studied using a wide spectrum of methods and divided into two clearly morphologically, geographically, cytologically and genetically isolated species: A. pallasii s. str.-North-East Kazakhstan, Western Siberia, and the Altai Mountains; A. caricifolium-Kyrgyzstan, Northwest China, South-East Kazakhstan until Zaysan Lake in the east. Despite serious genetic differences, both species are sisters and are related to species of the A. sect. Codonoprasum (Subg. Allium). Allium caricifolium differs from A. pallasii s. str. by taller stems, dense inflorescence, and with filaments longer than perianth. The possible phylogenetic reasons for the separation of these species are discussed. A nomenclature analysis of synonyms was carried out.

Electrical and thermal conductivity of low temperature CVD graphene: the effect of disorder.

In this paper we present a study of graphene produced by chemical vapor deposition (CVD) under different conditions with the main emphasis on correlating the thermal and electrical properties with the degree of disorder. Graphene grown by CVD on Cu and Ni catalysts demonstrates the increasing extent of disorder at low deposition temperatures as revealed by the Raman peak ratio, IG/ID. We relate this ratio to the characteristic domain size, La, and investigate the electrical and thermal conductivity of graphene as a function of La. The electrical resistivity, ρ, measured on graphene samples transferred onto SiO2/Si substrates shows linear correlation with La(-1). The thermal conductivity, K, measured on the same graphene samples suspended on silicon pillars, on the other hand, appears to have a much weaker dependence on La, close to K∼La1/3. It results in an apparent ρ∼K3 correlation between them. Despite the progressively increasing structural disorder in graphene grown at lower temperatures, it shows remarkably high thermal conductivity (10(2)-10(3) W K(-1) m(-1)) and low electrical (10(3)-3×10(5) Ω) resistivities suitable for various applications.

Strategies to Circumvent the Side-Effects of Immunotherapy Using Allogeneic CAR-T Cells and Boost Its Efficacy: Results of Recent Clinical Trials.

Despite the outstanding results of treatment using autologous chimeric antigen receptor T cells (CAR-T cells) in hematological malignancies, this approach is endowed with several constraints. In particular, profound lymphopenia in some patients and the inability to manufacture products with predefined properties or set of cryopreserved batches of cells directed to different antigens in advance. Allogeneic CAR-T cells have the potential to address these issues but they can cause life-threatening graft-versus-host disease or have shorter persistence due to elimination by the host immune system. Novel strategies to create an "off the shelf" allogeneic product that would circumvent these limitations are an extensive area of research. Here we review CAR-T cell products pioneering an allogeneic approach in clinical trials.

Geometries and tautomerism of OHN hydrogen bonds in aprotic solution probed by H/D isotope effects on (13)C NMR chemical shifts.

The (1)H and (13)C NMR spectra of 17 OHN hydrogen-bonded complexes formed by CH(3)(13)COOH(D) with 14 substituted pyridines, 2 amines, and N-methylimidazole have been measured in the temperature region between 110 and 150 K using CDF(3)/CDF(2)Cl mixture as solvent. The slow proton and hydrogen bond exchange regime was reached, and the H/D isotope effects on the (13)C chemical shifts of the carboxyl group were measured. In combination with the analysis of the corresponding (1)H chemical shifts, it was possible to distinguish between OHN hydrogen bonds exhibiting a single proton position and those exhibiting a fast proton tautomerism between molecular and zwitterionic forms. Using H-bond correlations, we relate the H/D isotope effects on the (13)C chemical shifts of the carboxyl group with the OHN hydrogen bond geometries.

Electron transfer in platinum(II) diimine-centered triads: mechanistic insights from photoinduced transient displacement current measurements.

The consequences of photoexcitation of a platinum diimine bisacetylide complex and its triads with phenothiazine species (McGarrah, J. E.; Eisenberg, R. Inorg. Chem. 2003, 42, 4355-4365) were investigated by the photoinduced transient displacement current (PTDC) method, with the aim of understanding the role of solvent in defining the nature and extent of intratriad electron transfer. PTDC enables reports on the distance of charge separation in photoexcited states. Photoexcition of the triad, Pt(dbbpy)(CCC(6)H(4)CH(2)(PTZ))(2) (where dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine), leads to formation of the (3)MLCT excited state, which in CH(2)Cl(2) is intramolecularly quenched by PTZ to form a charge-separated (CS) state, Pt(dbbpy(*-))(CCC(6)H(4)CH(2)(PTZ) CCC(6)H(4)CH(2)(PTZ(*+)); the CS state features a dipole moment oriented in essentially the opposite direction to that of the ground state. In toluene the last step of charge separation is shut down. In THF these two transient states are equilibrated, approximately as a 1:1 mixture of (3)MLCT and CS states, causing a complex, but instructive, PTDC response. The PTDC response for Pt(dbbpy)(CCC(6)H(5))(2), on the other hand, is similar in all solvents and shows a negative signal corresponding to a long-lived, and comparatively nonpolar, (3)MLCT state. The ground-state dipole moment, mu(g), weakly increases with solvent polarity, from approximately 11.5 D in toluene to approximately 15.5 D in THF and CH(2)Cl(2).

Exclusively Proton Conductive Membranes Based on Reduced Graphene Oxide Polymer Composites.

Proton exchange membranes are at the heart of various technologies utilizing electrochemical storage of intermittent energy sources and powering electrical devices. Current state of the art membranes are based on perfluorosulfonic acid, introduced more than a half century ago. Low specificity to protons accompanied by permeance by other species is one of the main impediments for various promising applications in green technologies in an energy sustainable economy. Here we present composite membranes that are exclusively proton selective and do not allow crossover of any ionic or molecular species other than protons. Membranes have high proton conductivity and exceptional mechanical and chemical stability and thus may significantly improve performance of hydrogen-based technologies such as electrolyzers, various kinds of fuel cells, and flow batteries in the future.

Ionic Conductance through Graphene: Assessing Its Applicability as a Proton Selective Membrane.

Inspired by recent reports on possible proton conductance through graphene, we have investigated the behavior of pristine graphene and defect engineered graphene membranes for ionic conductance and selectivity with the goal of evaluating a possibility of its application as a proton selective membrane. The averaged conductance for pristine chemical vapor deposited (CVD) graphene at pH1 is ∼4 mS/cm2 but varies strongly due to contributions from the unavoidable defects in our CVD graphene. From the variations in the conductance with electrolyte strength and pH, we can conclude that pristine graphene is fairly selective and the conductance is mainly due to protons. Engineering of the defects with ion beam (He+, Ga+) irradiation and plasma (N2 and H2) treatment showed improved areal conductance with high proton selectivity mostly for He-ion beam and H2 plasma treatments, which agrees with primarily vacancy-free type of defects produced in these cases confirmed by Raman analysis.

Characterization of commercial laminin preparations from human placenta in comparison to recombinant laminins 2 (alpha2beta1gamma1), 8 (alpha4beta1gamma1), 10 (alpha5beta1gamma1).

Laminins, a family of large heterotrimeric (alphabetagamma) proteins, are major components of basement membranes implicated in a variety of cellular functions. Different commercial laminin preparations isolated from human placenta have been widely used in functional studies but their molecular properties are poorly known. In the present study, we characterized several of these preparations by ELISA, silver staining and Western blotting, in comparison to mouse laminin 1 (alpha1beta1gamma1), and recombinant human laminins 2 (alpha2beta1gamma1), 8 (alpha4beta1gamma1) and 10 (alpha5beta1gamma1). The cell migration-promoting activity of different batches was also tested. The placenta laminin preparations differed from one another and consisted of highly fragmented proteins, a mixture of laminin isoforms, and/or contaminating fibronectin. Major functional differences between batches were also observed, reflecting molecular heterogeneity. Previous data obtained in functional studies using these preparations need to be interpreted with caution and may require revision, and future functional studies demand prior molecular characterization of the laminins, particularly their alpha-chain.

Surface-assisted transient displacement charge technique. I. Photoinduced charge transfer in self-assembled monolayers.

Surface-assisted photoinduced transient displacement charge (SPTDC) technique was developed in order to study light-induced charge transfer in surface-bound molecules and applied to investigation of self-assembled monolayers of 7-diethylaminocoumarin and 2,4-dinitrophenylamine. The dipole moment change measured by SPTDC correlates reasonably well with that measured in solution by standard PTDC technique and with semiempirical calculations. Shortening of the excited-state lifetime of surface-immobilized coumarin due to stimulated emission was observed in both fluorescence and dipole measurements. The dipole signal decline in low-polarity solvents indicates the importance of dipole-dipole interaction that causes reorientation of molecules upon photoexcitation.

Surface-assisted transient displacement charge technique. II. Effect of gases on photoinduced charge transfer in self-assembled monolayers.

Surface-assisted photoinduced transient displacement charge (SPTDC) technique was used to study charge transfer in self-assembled monolayers of 7-diethylaminocoumarin covalently linked to an oxide surface in the atmosphere of different gases. The dipole signal was found to be opposite to that in solution and dependent on the nature of the gas and its pressure. The results were explained by collision-induced relaxation that impedes uninhibited tilting of molecules onto the surface. Collisions with paramagnetic oxygen induce intersystem crossing to long-lived triplet dipolar states of coumarin with the rate close to half of that for the collision rate.