High-Quality Seizure-Like Activity from Acute Brain Slices Using a Complementary Metal-Oxide-Semiconductor High-Density Microelectrode Array System.

Complementary metal-oxide-semiconductor high-density microelectrode array (CMOS-HD-MEA) systems can record neurophysiological activity from cell cultures and ex vivo brain slices in unprecedented electrophysiological detail. CMOS-HD-MEAs were first optimized to record high-quality neuronal unit activity from cell cultures but have also been shown to produce quality data from acute retinal and cerebellar slices. Researchers have recently used CMOS-HD-MEAs to record local field potentials (LFPs) from acute, cortical rodent brain slices.

Path to autonomous soil sampling and analysis by ground-based robots.

Good site characterization is essential for the selection of remediation alternatives for impacted soils. The value of site characterization is critically dependent on the quality and quantity of the data collected. Current methods for characterizing impacted soils rely on expensive manual sample collection and off-site analysis.

Towards a dynamic compression facility at the ESRF.

Results of the 2018 commissioning and experimental campaigns of the new High Power Laser Facility on the Energy-dispersive X-ray Absorption Spectroscopy (ED-XAS) beamline ID24 at the ESRF are presented. The front-end of the future laser, delivering 15 J in 10 ns, was interfaced to the beamline. Laser-driven dynamic compression experiments were performed on iron oxides, iron alloys and bismuth probed by online time-resolved XAS.

Sources and subsurface transport of dissolved reactive phosphorus in a semiarid, no-till catchment with complex topography.

The subsurface transport of dissolved reactive phosphorus (DRP) from artificially drained agricultural fields can impair water quality, especially in no-till fields. The distribution of soil P in the wheat (Triticum aestivum L.)-dominated Palouse region in the inland U.

Mining the Drilosphere: Bacterial Communities and Denitrifier Abundance in a No-Till Wheat Cropping System.

Earthworms play important roles in no-till cropping systems by redistributing crop residue to lower soil horizons, providing macropores for root growth, increasing water infiltration, enhancing soil quality and organic matter, and stimulating nitrogen cycling. The soil impacted by earthworm activity, including burrows, casts, and middens, is termed the drilosphere. The objective of this study was to determine the effect of earthworms on soil microbial community composition in the drilosphere at different landscape slope positions.

Filter Membrane Effects on Water-Extractable Phosphorus Concentrations from Soil.

To accurately assess P concentrations in soil extracts, standard laboratory practices for monitoring P concentrations are needed. Water-extractable P is a common analytical test to determine P availability for leaching from soils, and it is used to determine best management practices. Most P analytical tests require filtration through a filter membrane with 0.

Dimethyl sulfoxide-induced conformational state of Na(+)/K(+)-ATPase studied by proteolytic cleavage.

Effects of dimethyl sulfoxide (Me(2)SO) on substrate affinity for phosphorylation by inorganic phosphate, on phosphorylation by ATP in the absence of Na(+), and on ouabain binding to the free form of the Na(+)/K(+)-ATPase have been attributed to changes in solvation of the active site or Me(2)SO-induced changes in the structure of the enzyme. Here we used selective trypsin cleavage as a procedure to determine the conformations that the Na(+)/K(+)-ATPase acquires in Me(2)SO medium. In water or in Me(2)SO medium, Na(+)/K(+)-ATPase exhibited after partial proteolysis two distinct groups of fragments: (1) in the presence of 0.

The Occlusion of Rb(+) in the Na(+)/K(+)-ATPase. I. The identity of occluded states formed by the physiological or the direct routes: occlusion/deocclusion kinetics through the direct route.

Occlusion of K(+) or its congeners in the Na(+)/K(+)-ATPase occurs after K(+)-dependent dephosphorylation (physiological route) or in media lacking ATP and Na(+) (direct route). The effects of P(i) or ATP on the kinetics of deocclusion of the K(+)-congener Rb(+) formed by each of the above mentioned routes was independent of the route of occlusion, which suggests that both routes lead to the same enzyme intermediate. The time course of occlusion via the direct route can be described by the sum of two exponential functions plus a small component of very high velocity.

Outcome for patients with carotid stenosis undergoing carotid endarterectomy, the cerebral condition followed by extra/intracranial ultrasound examinations.

Seventy-six patients undergoing carotid endarterectomy were studied to estimate the effect of operation, evaluate the accessible methods of examination and disclose the complications owing to the operation. In addition, the hypothesis that the pulsatility index in MCA measured by the Doppler method could disclose severe ischemia and risk of complications during endarterectomy was tested. The study was a prospective study of patients operated at the University Hospital in Odense in the years 1991-1996.

Are the states that occlude rubidium obligatory intermediates of the Na(+)/K(+)-ATPase reaction?

In the Albers-Post model, occlusion of K(+) in the E(2) conformer of the enzyme (E) is an obligatory step of Na(+)/K(+)-ATPase reaction. If this were so the ratio (Na(+)/K(+)-ATPase activity)/(concentration of occluded species) should be equal to the rate constant for deocclusion. We tested this prediction in a partially purified Na(+)/K(+)-ATPase from pig kidney by means of rapid filtration to measure the occlusion using the K(+) congener Rb(+).

Stimulation of ouabain binding to Na,K-ATPase in 40% dimethyl sulfoxide by a factor from Na,K-ATPase preparations.

In 40% dimethyl sulfoxide (Me2SO) high-affinity ouabain (O) binding to Na,K-ATPase (E) is promoted by Mg2+ in the absence of inorganic phosphate (Pi) (Fontes et al., Biochim. Biophys.

An attachment for nondestructive, fast quenching of samples in rapid-mixing experiments.

The present paper describes a quenching-and-washing chamber (QWC) to be used with a rapid-mixing apparatus (RMA) for the study of processes in the millisecond time scale. The QWC enables fast, nondestructive quenching by cooling and dilution of reactants in particulate systems that can be trapped on a filter. The reaction mixture (e.

The effect of ionic strength and specific anions on substrate binding and hydrolytic activities of Na,K-ATPase.

The physiological ligands for Na,K-ATPase (the Na,K-pump) are ions, and electrostatic forces, that could be revealed by their ionic strength dependence, are therefore expected to be important for their reaction with the enzyme. We found that the affinities for ADP3-, eosine2-, p-nitrophenylphosphate, and V(max) for Na,K-ATPase and K+-activated p-nitrophenylphosphatase activity, were all decreased by increasing salt concentration and by specific anions. Equilibrium binding of ADP was measured at 0-0.

The effect of dimethylsulfoxide on the substrate site of Na+/K(+)-ATPase studied through phosphorylation by inorganic phosphate and ouabain binding.

To obtain further information on the role of H2O at the substrate site of Na+/K(+)-ATPase, we have studied the enzymes reaction with P(i) and ouabain in 40% (v/v) Me2SO (dimethylsulfoxide). When the enzyme (E) was incubated with ouabain (O) for 5 min in a 40% (v/v) Me2SO-medium with 5 mM MgCl2 and 0.5 mM KCl (but no phosphate), ouabain was bound (as EO).

Kinetics of K(+)-stimulated dephosphorylation and simultaneous K+ occlusion by Na,K-ATPase, studied with the K+ congener Tl+. The possibility of differences between the first turnover and steady state.

Using the K+ congener Tl+ and rapid mixing combined with special quench techniques, we have investigated (at 20 degrees C) what is usually assumed to be the enzymatic correlate of active transport of K+ by Na,K-ATPase: the Tl(+)-catalyzed dephosphorylation of the K(+)-sensitive phosphointermediate(s), EP, and the resulting occlusion of Tl+ in the enzyme protein. We measured [EP] and [occluded Tl] as a function of time in phosphorylation, as well as dephosphorylation experiments with the following results. First, we found that with 150 mM Na+ and 600 mM Na(+)--NO3- was the anion--[Tl+] = 0.

The role of Mg2+ and K+ in the phosphorylation of Na+,K(+)-ATPase by ATP in the presence of dimethylsulfoxide but in the absence of Na+.

We have previously demonstrated that Na+,K(+)-ATPase can be phosphorylated by 100 microM ATP and 5 mM Mg2+ and in the absence of Na+, provided that 40% dimethylsulfoxide (Me2SO) is present. Phosphorylation was stimulated by K+ up to a steady-state level of about 50% of Etot (Barrabin et al. (1990) Biochim.

Preservation of rabbit kidneys using a solution containing hydrolyzed starch.

An organ preservation solution has been developed by combining some features of the hypertonic citrate formulation of Ross, Marshall, and Escott (RME) with some features of UW solution. Specifically the solution (HP16) contains a balance of cations similar to that in RME and the same concentration of citrate, but sulfate is replaced by chloride and mannitol by a starch hydrolysis product (SHP). A gelatin-derived polypeptide (Haemaccel) is included to provide colloid osmotic pressure.

Functional significance of the oligomeric structure of the Na,K-pump from radiation inactivation and ligand binding.

The present article is concerned with the oligomeric structure and function of the Na,K-pump (Na,K-ATPase). The questions we have addressed, using radiation inactivation and target size analysis as well as ligand binding, are whether the minimal structural unit and the functional unit have more than one molecule of the catalytic subunit, alpha. We first discuss the fundamentals of the radiation inactivation method and emphasize the necessity for rigorous internal standardization with enzymes of known molecular mass.

Phosphorylation of Na+, K(+)-ATPase by ATP in the presence of K+ and dimethylsulfoxide but in the absence of Na+.

Purified Na+, K(+)-ATPase was phosphorylated by [gamma-32P]ATP in a medium containing dimethylsulfoxide and 5 mM Mg2+ in the absence of Na+ and K+. Addition of K+ increased the phosphorylation levels from 0.4 nmol phosphoenzyme/mg of protein in the absence of K+ to 1.

[Concepts of the oligomeric structure and function of Na, K-ATPase based on the results of studying ligand binding and of determining the size of the molecular target].

This review is devoted to the discussion of the sizes and molecular structure of the minimal functional unit of Na, K-ATPase. Special attention is paid to the data obtained by radiation inactivation method and studies on ligand binding. The model for the stepwise radiation inactivation of Na, K-ATPase is proposed.

A model for the stepwise radiation inactivation of the alpha 2-dimer of Na,K-ATPase.

This study is a direct continuation of Jensen, J., and Nørby, J. G.