Dynamic changes in genomic and social structures in third millennium BCE central Europe

Europe’s prehistory oversaw dynamic and complex interactions of diverse societies, hitherto unexplored at detailed regional scales. Studying 271 human genomes dated ~4900 to 1600 BCE from the European heartland, Bohemia, we reveal unprecedented genetic changes and social processes. Major migrations preceded the arrival of “steppe” ancestry, and at ~2800 BCE, three genetically and culturally differentiated groups coexisted. Corded Ware appeared by 2900 BCE, were initially genetically diverse, did not derive all steppe ancestry from known Yamnaya, and assimilated females of diverse backgrounds. Both Corded Ware and Bell Beaker groups underwent dynamic changes, involving sharp reductions and complete replacements of Y-chromosomal diversity at ~2600 and ~2400 BCE, respectively, the latter accompanied by increased Neolithic-like ancestry. The Bronze Age saw new social organization emerge amid a ≥40% population turnover.Introduction Results - General sample overview - Bohemia before Corded Ware (pre-CW, before ~2800 BCE) - Corded Ware - Bell Beaker - EBA—Únětice culture Discussion Materials and methods - Processing sites for the newly reported individuals - Sampling - DNA extraction - DNA libraries and in-solution capture - Sequencing - Sex determination and authentication - Genotyping - Mitochondrial and Y chromosome haplogroups - Principal components analysis - Ancestry decomposition and admixture modeling - Y haplogroup frequency simulation

Domains and anomalous adsorption isotherms of dipalmitoylphosphatidylcholine membranes and lipophilic ions: pentachlorophenolate, tetraphenylborate, and dipicrylamine.

Dipalmitoylphosphatidylcholine (DPPC) vesicles acquire negative surface charge on adsorption of negatively charged pentachlorophenolate (PCP-), and lipophilic ions tetraphenylborate (TPhB-), and dipicrylamine (DPA-). We have obtained (a) zeta-potential isotherms from the measurements of electrophoretic mobility of DPPC vesicles as a function of concentration of the adsorbing ions at different temperatures (25-42 degrees C), and (b) studied the effect of PCP- on gel-to-fluid phase transition by measuring the temperature dependence of zeta-potential at different PCP- concentrations. The zeta-potential isotherms of PCP- at 25, 32, and 34 degrees C correspond to adsorption to membrane in its gel phase. At 42 degrees C the zeta-potential isotherm corresponds to membrane in its fluid phase. These isotherms are well described by a Langmuir-Stern-Grahame adsorption model proposed by McLaughlin and Harary (1977. Biochemistry. 15:1941-1948). The zeta-potential isotherm at 37 degrees C does not follow the single-phase adsorption model. We have also observed anomalous adsorption isotherms for lipophilic ions TPhB- and DPA- at temperatures as low as 25 degrees C. These isotherms demonstrate a gel-to-fluid phase transition driven by ion adsorption to DPPC membrane during which the membrane changes from weakly to a strongly adsorbing state. The anomalous isotherm of PCP- and the temperature dependence of zeta-potential can be described by a two-phase model based on the combination of (a) Langmuir-Stern-Grahame model for each phase, (b) the coexistence of gel and fluid domains, and (c) depression of gel-to-fluid phase transition temperature by PCP-. Within the anomalous region the magnitude of zeta-potential rapidly increases concentration of adsorbing species, which was characterized in terms of a Esin-Markov coefficient. This effect can be exploited in membrane-based devices. Comments are also made on the possible effect of PCP, as an uncoupler, in energy transducing membranes

Adsorption of ruthenium red to phospholipid membranes.

We have measured the distribution of the hexavalent ruthenium red cation (RuR) between water and phospholipid membranes, have shown the critical importance of membrane negative surface charge for RuR binding, and determined the association constant of RuR for different phospholipid bilayers. The studies were performed with liposomes made of mixtures of zwitterionic L-alpha-phosphatidylcholine (PC), and one of the negatively charged phospholipids: L-alpha-phosphatidylserine (PS), L-alpha-phosphatidylinositol (PI), or L-alpha-phosphatidylglycerol (PG). Lipid composition of PC:PX membranes was 1:0, 19:1, 9:1, and 4:1. Liposomes were processed using freeze-and-thaw treatment, and their size distribution was characterized by light scattering and electron microscopy. Experimental distribution isotherms of RuR obtained by ultracentrifugation and spectrophotometry can be reproduced with the Langmuir-Stern-Grahame model, assuming that RuR behaves in the diffuse double layer as an ion with effective valency < 6. In terms of this model, PC-PS, PC-PI, and PC-PG membranes were found to be electrostatically equivalent and the intrinsic association constants of RuR were obtained. RuR has highest affinity to PS-containing membranes; its association constant for PC-PI and PC-PG membranes is about 5 times smaller than that for PC-PS membranes. From the comparison of RuR binding to mixed negatively charged phospholipid membranes and RuR binding to sarcoplasmic reticulum (SR), we conclude that the low-affinity RuR binding sites may indeed be associated with the lipid bilayer of SR

Hot Electron Injection into Liquid Argon from a Tunnel Cathode

Hot electrons from a tunnel cathode have been injected into liquid argon (99.998% pure) at 87°K. The current vs voltage characteristics indicate that the injected hot electrons thermalize very slowly, losing their energy only by elastic scattering processes and finally by capture by the dilute impurities. The deduced thermalization time and distance are very long compared with that in helium, where bubble formation is responsible for energy loss

Modification of ion transport in lipid bilayer membranes in the presence of 2,4-dichlorophenoxyacetic acid. I. Enhancement of cationic conductance and changes of the kinetics of nonactin-mediated transport of potassium.

We have found that herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has the ability to increase the rate of transport of positive ions of several kinds, and to inhibit transport of negatively charged tetraphenylborate ions in lipid bilayer membranes. It has been found that only the neutral form of 2,4-D is transport active, whereas the ionized from of 2,4-D does not modify transport of ions, and does not by itself permeate through lipid membranes. The results suggest that the enhancement of transport of positively charged ions such as tetraphenylarsonium + and nonactin-K+ is dominated by the increase of the ion translocation rate constant. It has been shown that the enhancement of nonactin-mediated transport of K+ by 2,4-D can be accounted for by a simple carrier model. We have observed that a 2,4-D concentration above 3 X 10(-4) M the potassium ion transport in phosphatidylcholine-cholesterol as well as in cholesterol-free glycerolmonooleate membranes is enhanced to such a degree that, depending upon the concentration of potassium ions, it becomes limited by the rate of recombination of K+ with nonactin, and/or by backdiffusion of unloaded nonactin molecules. Furthermore, the effect of 2,4-D is enhanced by ionic strength of aqueous solution. From the changes of kinetic parameters of nonactin-K+ transport, as well as from the changes of membranes conductance due to tetraphenylarsonium + ions, we have estimated the changes of the electrical potential of the membrane interior. We have found that the potential of the interior of the membrane becomes more negative in the presence of 2,4-D, and that its change is proportional to the aqueous concentration of 2,4-D. The effect of 2,4-D on ion transport has been attributed to a layer of 2,4-D molecules absorbed within the interfacial region, and having a dipole moment directed toward the aqueous medium. The results of kinetic studied of nonactin-K+ transport suggest that this layer is located on the hydrocarbon side of the interface

Adsorption to dipalmitoylphosphatidylcholine membranes in gel and fluid state: pentachlorophenolate, dipicrylamine, and tetraphenylborate.

We measured the dependence of electrophoretic mobility of dipalmitoylphosphatidylcholine (DPPC) vesicles on the aqueous concentration of negatively charged ions of pentachlorophenol (PCP), dipicrylamine (DPA), and tetraphenylborate (TPhB). The objective was to determine how the physical state of hydrocarbon chains of lipids affects adsorption of lipophilic ions. The studies were done at 25 and 42 degrees C to determine adsorption properties of DPPC membrane in the gel and fluid state, respectively. From the analysis of zeta-potential isotherms in terms of Langmuir-Stern-Grahame model we obtained the association constant, K, the area of the adsorption site, Ps, and the linear partition coefficient, beta. Results: K, (x 10(4)M-1): K(gel): PCP (0.49 +/- 0.28), DPA (25 +/- 10), TPhB (31 +/- 10); K(fluid): PCP (4.5 +/- 0.9), DPA (74 +/- 21), TPhB (59 +/- 14); Ps, (nm2): Ps(gel): PCP (5.4 +/- 2.3), DPA (5.9 +/- 2), TPhB (5.0 +/- 1.7); Ps(fluid): PCP (4.5 +/- 0.4), DPA (5.2 +/- 0.4), TPhB (4.1 +/- 0.2); beta, (x 10(-5) m): beta(gel): PCP (0.15 +/- 0.09), DPA (7.1 +/- 0.3), TPhB (10 +/- 7); beta(fluid): PCP (1.7 +/- 0.3), DPA (24 +/- 7), TPhB (24 +/- 6). It was interesting to find that the adsorption site area for PCP, DPA, and TPhB were very similar for both the gel and fluid membranes; also, the areas were independent of the size and molecular structure of the adsorbing species. Using a simple discrete charge model the adsorption site areas for all species were consistent with a dielectric constant of 8-10 and with an ion adsorption depth of 0.4-0.6 nm below the water/dielectric interface. The delta delta G0 = delta G0(gel) - delta G0(fluid) was found to be about twice as large for PCP than for DPA and TPhB. This indicates that PCP will be significantly more adsorbed in the fluid and disordered regions of biomembranes, whereas the distribution of DPA and TPhB is expected to be relatively more even

Modification of ion transport in lipid bilayer membranes in the presence of 2,4-dichlorophenoxyacetic acid. II. Suppression of tetraphenylborate conductance and changes of interfacial potentials.

It has been shown that the blocking of negatively charged tetraphenylborate ion transport in phosphatidylcholine (PC)-cholesterol membranes by the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) is dominated by suppression of TPhB- diffusion across the membrane interior, rather than by the decrease of adsorption of TPhB- ions at the membrane surface. The blocking effect can be associated with the decrease of electric potential inside the membrane with respect to that of the aqueous medium, this decreases being proportional to the concentration of 2,4-D in the aqueous solution. It has been estimated that 25 - 30% of the total 2,4-D-induced change of the potential difference is between the plane of absorption of TPhB- and the aqueous solution, and the remaining fraction is between the membrane interior and the absorption plane. The results of this study support the dipolar hypothesis of 2,4-D action in lipid membranes. These conclusions are further supported by measurements changes of electric potential difference across air/water and air/lipid monolayer/water interfaces. It has been found that the electric potential of the nonpolar side of the interface decreases in the presence of neutral molecules of 2,4-D and that this effect becomes more prominent in presence of electrolyte. We have confirmed that PC-cholesterol monolayer cannot be considered as a model for half of the bilayer membrane because of the disagreement between the changes of the interfacial potential difference of PC-cholesterol monolayers and those determined from studied of transport of positive and negative ions across bilayer membranes. In contract, we have found close agreement between the 2,4-D-induced changes of electric potential of the lipid hydrocarbon region in glycerolmonooleate (GMO) membranes and GMO monolayers. We suggest that the action of 2,4-D in lipid membranes is not associated with the changes of orientation of dipoles of lipids constituting the membranes, but rather with a layer of 2,4-D molecules absorbed at the nonpolar/polar membrane boundary