Long-term inactivation of bacteriophage PRD1 as a function of temperature, pH, sodium and calcium concentration

2016 ◽  
Vol 103 ◽  
pp. 66-73 ◽  
Author(s):  
Jack F. Schijven ◽  
Gholamreza Sadeghi ◽  
S. Majid Hassanizadeh
Keyword(s):  
Calcium Concentration ◽  
Bacteriophage Prd1

scholarly journals Selective Induction of LTP and LTD by Postsynaptic [Ca2+]i Elevation

1999 ◽  
Vol 81 (2) ◽  
pp. 781-787 ◽  
Author(s):  
Shao-Nian Yang ◽  
Yun-Gui Tang ◽  
Robert S. Zucker
Keyword(s):  
Calcium Concentration ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Biological Information ◽  
Synaptic Modulation ◽  
Ca1 Pyramidal Cells ◽  
Caged Calcium ◽  
Term Potentiation ◽  
Calcium Compound

Selective Induction of LTP and LTD by Postsynaptic [Ca2+]i Elevation. Long-term potentiation (LTP) and long-term depression (LTD), two prominent forms of synaptic plasticity at glutamatergic afferents to CA1 hippocampal pyramidal cells, are both triggered by the elevation of postsynaptic intracellular calcium concentration ([Ca2+]i). To understand how one signaling molecule can be responsible for triggering two opposing forms of synaptic modulation, different postsynaptic [Ca2+]i elevation patterns were generated by a new caged calcium compound nitrophenyl-ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid in CA1 pyramidal cells. We found that specific patterns of [Ca2+]i elevation selectively activate LTP or LTD. In particular, only LTP was triggered by a brief increase of [Ca2+]i with relatively high magnitude, which mimics the [Ca2+]i rise during electrical stimulation typically used to induce LTP. In contrast, a prolonged modest rise of [Ca2+]i reliably induced LTD. An important implication of the results is that both the amplitude and the duration of an intracellular chemical signal can carry significant biological information.

Non-Destructive Analysis of 14th–19th Century European Handmade Papers

2016 ◽  
Vol 37 (2) ◽  
Author(s):  
Timothy Barrett ◽  
Mark Ormsby ◽  
Joseph B. Lang
Keyword(s):  
Calcium Carbonate ◽  
19Th Century ◽  
Calcium Concentration ◽  
Natural Ageing ◽  
Destructive Analysis ◽  
Non Destructive ◽  
Over Time

AbstractNon-destructive analysis of 1,578 paper specimens made between the fourteenth and the nineteenth centuries was undertaken in an effort to better understand changes in paper composition over time and how these variations might affect paper stability during long term natural ageing. Gelatine content and colour were determined using UV/Vis/NIR spectrometry. Residual metals were measured using XRF. These components included potassium and sulfur as elements indicative of alum concentration; iron as a typical paper contaminant; and calcium, which is often associated with compounds such as calcium carbonate that can serve as alkaline reserves. The research demonstrated that papers that are lighter in colour (closer to white) are associated with higher levels of gelatine and calcium, and lower levels of iron. The survey also showed significant decreases in gelatine and calcium concentration over time with the largest differences coinciding with the rise of printing around 1500. The drop in pH over the centuries observed by other researchers is explained by the decreases in these two components rather than by a rise in alum concentration, which remained fairly stable. The craftsmanship of the specimens was evaluated using materials and workmanship ratings which showed better quality paper associated with higher gelatine and calcium concentrations and colour closer to white. Poorer quality papers were associated with higher iron levels and greater thickness.

Calcium-induced long-term depression in the visual cortex of the rat in vitro

1996 ◽  
Vol 76 (2) ◽  
pp. 984-994 ◽  
Author(s):  
A. Artola ◽  
T. Hensch ◽  
W. Singer
Keyword(s):  
Visual Cortex ◽  
Calcium Concentration ◽  
Long Term Potentiation ◽  
Transient Increase ◽  
Resting Membrane Potential ◽  
Long Term Depression ◽  
Normal Medium ◽  
Gabaa Receptor Antagonist ◽  
In Cells

1. In many brain areas, including neocortex and hippocampus, excitatory synapses can undergo both long-term potentiation (LTP) and long-term depression (LTD). It is established that a change in the postsynaptic calcium concentration ([Ca2+]i) is critical for the induction of both LTP and LTD. Protocols that induce these long-term synaptic modifications typically involve afferent stimulation. But, in hippocampus, LTP can also be induced by a transient increase of the extracellular calcium concentration ([Ca2+]o). The purpose of the present study was to determine whether raising [Ca2+]o also induces long-term modifications of excitatory synaptic transmission in the neocortex. 2. Intracellular recordings were obtained from regular spiking cells in layers II-III of slices of the rat visual cortex. Test stimuli were evoked with stimulation electrodes located in the white matter (w.m.) below the recorded cell and intracortically (i.c.) adjacent to the cell. Both the depolarizing slope and the amplitude of excitatory postsynaptic potentials (EPSPs) were measured. For exposure to elevated [Ca2+]o, the normal medium ([Ca2+]o = 2 mM) was exchanged for a period of 10 min against a medium containing 4 mM [Ca2+]o. 3. Elevated [Ca2+]o leads, after return to normal medium, to a long-lasting decrease of intracellularly recorded synaptic responses to both w.m. and i.c. stimulation even if activation of these two pathways is discontinued or N-methyl-D-aspartate (NMDA) receptors are blocked during elevated [Ca2+]o. This decrease is due to reduced efficacy of excitatory transmission because it is observed in the presence of the gamma-aminobutyric acid-A (GABAA) receptor antagonist, bicuculline. 4. Induction of LTD by raising [Ca2+]o is voltage dependent. First, elevated [Ca2+]o elicits LTD only in cells whose resting membrane potential (Vmr) is less polarized than -79 mV (and more polarized than -70 mV, which is the Vmr of the least polarized cell). Second, hyperpolarizing cells whose Vmr is in this susceptible range by 20 mV below Vmr during exposure to high [Ca2+]o prevents Ca2+-induced LTD. Third, when elevated [Ca2+]o is associated with postsynaptic depolarizing pulses, LTD is readily induced in cells whose Vmr is more polarized than -79 mV. This voltage dependence implies that the depression is induced by a postsynaptic process and hence that it occurs at synapses formed by excitatory terminals on the recorded neuron. 5. Assuming that a transient elevation of [Ca2+]o leads to an increase of [Ca2+]i, the results of this study suggest that a transient increase of [Ca2+]i is sufficient to elicit LTD. This may provide a mechanism for the induction of heterosynaptic LTD, a depression that occurs in afferents that are silent while the postsynaptic neuron is activated by other inputs.

The Activity and Characteristics of the Ca2+ ATPase of Fish Gills in Relation to Environmental Calcium Concentrations

1981 ◽  
Vol 90 (1) ◽  
pp. 115-121
Author(s):  
K. L. SHEPHARD
Keyword(s):  
Atpase Activity ◽  
Calcium Concentration ◽  
Previous Experiment ◽  
Close Correlation ◽  
Plasma Calcium ◽  
Short Term ◽  
Absolute Level ◽  
Atpase System ◽  
External Calcium

The concentration of plasma calcium and the activity of the gill Ca2+- ATPase has been measured in roach from several waters. Plasma calcium concentrations in these fish vary very little (2·62 ± 0·17 mM) despite great variation in the external calcium concentration between waters (0·40 to 2·92 mM). There is, however, a close correlation between Ca2+ ATPase activity and external calcium concentration, consistent with the view that differences in the requirement for calcium transport are accommodated by variation in the Ca2+ ATPase system. These results are discussed in relation to those of a previous experiment, where the short term effects of changing external calcium were considered. It is suggested that variation in the absolute level of Ca2+ ATPase activity represents the long term adaptation of the roach to different calcium concentrations.

scholarly journals Functional and Structural Details about the Fabella: What the Important Stabilizer Looks Like in the Central European Population

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Nicole Helene Hauser ◽  
Sebastian Hoechel ◽  
Mireille Toranelli ◽  
Joerg Klaws ◽  
Magdalena Müller-Gerbl
Keyword(s):  
Calcium Concentration ◽  
Femoral Condyle ◽  
Lateral Meniscus ◽  
European Population ◽  
Clinical Routine ◽  
Central European ◽  
Structural Details ◽  
Central European Population

The posterolateral corner of the knee accommodating the fabella complex is of importance in orthopaedic surgery. Unfortunately, there is a lack of data in literature for clinical routine. Therefore, we investigated the fabella’s characteristics, biomechanical nature, and present histologic details. Of special interest were the fabella’s occurrence and position, calcium concentration as long-term load intake indicator, and the histology. Within our analysis, fabellae were found in 30.0% of all datasets, located on the upper part of the posterolateral femoral condyle. The region of fabella contact on this condyle showed a significantly lower calcium concentration than its surroundings. Histologically, the fabella showed no articular cartilage but a clearly distinguishable fabellofibular ligament that consisted of two bundles: one, as already described in literature inserted at the fibular tip, and another part newly described on the top of the lateral meniscus. In its role of stabilizing the soft tissue structures of the posterolateral knee, the fabella seems to serve as suspension for the ligaments evolving from its base. Even though a joint formation of any kind is unlikely, the presence of a fabella needs to be kept in mind during knee examination and any surgical procedures.

An Active Role for Astrocytes in Synaptic Plasticity?

2010 ◽  
Vol 104 (3) ◽  
pp. 1216-1218 ◽  
Author(s):  
Ian Wenker
Keyword(s):  
Synaptic Plasticity ◽  
Transgenic Mice ◽  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Active Role ◽  
Intracellular Calcium Concentration ◽  
Synaptic Potentiation ◽  
Calcium Dependent

Recently, Henneberger and colleagues blocked hippocampal long-term synaptic potentiation (LTP) induction by “clamping” intracellular calcium concentration of individual CA1 astrocytes, suggesting calcium-dependent gliotransmitter release from astocytes plays a role in hippocampal LTP induction. However, using transgenic mice to manipulate astrocytic calcium, Agulhon and colleagues demonstrated no effect on LTP induction. Until the question of how intracellular calcium causes gliotransmitter release is answered, the role of astrocytes in synaptic plasticity will be incompletely understood.

scholarly journals MO795CALCIUM BALANCE AND CKD-MBD PARAMETERS DIFFERENCES OF CITRATE VS. ACETATE DIALYSATE

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Jose Jesus Broseta Monzo ◽  
Luis Carlos López Romero ◽  
Diana Rodríguez ◽  
Elena Guillen Olmos ◽  
Pilar Sánchez-Pérez ◽  
...  
Keyword(s):  
Calcium Concentration ◽  
Essential Feature ◽  
Blood Analysis ◽  
Ionized Calcium ◽  
Calcium Balance ◽  
Long Term Effects ◽  
Long Term Outcomes ◽  
Negative Effect ◽  
Potential Benefits

Abstract Background and Aims Dialysate composition is an essential feature of hemodialysis treatment. The use of acetate as the dialysate buffer and its calcium concentration are still topics of debate. Calcium transfer during dialysis sessions is related to short-term (hemodynamic tolerance and arrhythmias) and long-term effects (cardiovascular calcification and mortality). This study aims to identify the potential benefits derived from acetate-free dialysis by using citrate as a buffer in terms of calcium balance and CKD-MBD biomarkers. Method We performed a prospective crossover study that analyzed 24 dialysis sessions, 12 with each dialysate buffer, on every patient. Ionized calcium and CKD-MBD parameters were analyzed with each acidifier. Both dialysates had a calcium concentration of 1.5 mml/L. The remaining hemodialysis patients’ parameters were unchanged during the study period. Results No differences were found between pre-dialytical ionized calcium (iCa) (1,11 ± 0,12 vs. 1,08 ± 0,12 mmol/L) in both groups. However, we identified a significant iCa increase in the sessions were acetate dialysate was used, both in immediate (1,29 ± 0,07 mmol/L) and in 30-minutes post-dialytical blood analysis (1,22 ± 0,07 mmol/L). Whereas iCa levels remained stable during the immediate (1,07 ± 0,06 mmol/L) and 30-minutes post-dialytical analysis (1,08 ± 0,11 mmol/L) when using citrate. On the other hand, pre-dialysis albumin-corrected total calcium was higher with acetate (8,9 ± 0,6 vs. 8,31 ± 0,75 mg/dL, p = 0,003) and PTH was lower with acetate (169 vs. 267 pg/mL, p < 0,001). Conclusion Acetate-free dialysis using citrate as an acidifier stabilizes iCa levels during dialysis sessions while maintaining a neutral or negative effect in calcium balance. This analytical benefit may translate into better cardiovascular long-term outcomes.

scholarly journals Reversible Slow Desensitization of the Acid-Sensing Ion Channel (ASIC) 1a

2021 ◽  
Author(s):  
Margarita S Komarova ◽  
Andrey R Bukharev ◽  
Natalia N Potapieva ◽  
Denis B Tikhonov
Keyword(s):  
Steady State ◽  
Recovery Time ◽  
Time Course ◽  
Calcium Concentration ◽  
Response Amplitude ◽  
Progressive Decrease ◽  
Cell Recording ◽  
Ph Conditions ◽  
Different Origin

Abstract Among the proton-activated channels of the ASIC family, ASIC1a exhibits a specific tachyphylaxis phenomenon in the form of a progressive decrease in the response amplitude during a series of activations. This process is well known, but its mechanism is poorly understood. Here, we demonstrated a partial reversibility of this effect by long-term whole-cell recording of CHO cells transfected with rASIC1a cDNA. Long but infrequent acidifications provided the same recovery time course as short acidifications of the same frequency. Steady-state desensitization is not related to the slow desensitization and attenuates the development of the slow desensitization. Consequently, we found that drugs, which facilitate ASIC1a activation (e.g., amitriptyline), cause an enhancement of slow desensitization, while inhibition of ASIC1a by 9-aminoacridine attenuates the slow desensitization. In summary, for influences of vastly different origin, including increase of calcium concentration, different pH conditions, and action of modulating drugs, we found a correlation between the effect on response amplitude and on development of slow desensitization. Thus, our results prove that a slow desensitization requires the open ion-permeable state.

The effect of fluoride ingestion on the response of the rat to parathormone and calcitonin

1969 ◽  
Vol 47 (5) ◽  
pp. 477-481 ◽  
Author(s):  
Leon Kraintz
Keyword(s):  
Calcium Concentration ◽  
Plasma Calcium ◽  
Similar Degree ◽  
Distilled Water ◽  
Calcium Response ◽  
Growing Rat ◽  
Plasma Calcium Concentration ◽  
Slight Elevation ◽  
Intact Rats

Long-term ingestion of 100 p.p.m. of fluoride as NaF in the drinking water of the intact growing rat resulted in a slight but significant decrease of fasting plasma calcium concentration when compared with that in controls given distilled water. The plasma calcium response of both groups of rats to administered calcitonin was similar. The effect of parathormone on the plasma calcium response of thyroparathyroidectomized rats given NaF or distilled water showed a similar degree of hypercalcemia. Intact rats receiving fluoride or distilled water, given the same amount of parathormone, exhibited only a slight elevation of plasma calcium which was similar in both groups. It is concluded that the long-term ingestion of fluoride probably does not alter the response of the growing rat to endogenous or exogenous parathormone or calcitonin.

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