Elevation Of Calcium Ion Concentration Research Articles

Electrochemical investigation on calcium ion sensing and steady-state diffusion analysis using zinc oxide modified glassy carbon electrode

The concentration of calcium ions in human blood serum typically falls within a narrow range of 2 and 2.5 mmol/L. However, hyperthyroidism, resulting from an overactive parathyroid gland, can lead to an elevation of calcium ion concentration beyond 2.5 mmol/L, necessitating the development of a highly sensitive and selective electrochemical sensor for calcium ion detection. To address this issue, a highly sensitive and selective electrochemical sensor based on zinc oxide nanoparticles-chitosan composite modified glassy carbon electrode (GC/ZnO-Chitosan) was fabricated for the detection of calcium ions. Cyclic voltammetric analysis revealed that the fabricated electrode possesses excellent electrocatalytic activity for calcium ion oxidation and reduction. The fabricated electrode showed high sensitivity (449.887 µA mM−1) towards calcium ions over the wide detection range of 2.14–3.5 mM with a low detection limit of 2.26 µM, and a low quantification limit of 7.45 µM. Moreover, the fabricated electrode showed fast response time (<25 s) due to the synergistic effect of enhanced adsorption of calcium ions (Γ=2.17×10-7 mol cm−2), efficient electron shuttling capacity of ZnO nanoparticles between GCE (ks=6.01 s−1) and the adsorbed calcium ions, and enhanced diffusion of calcium ions (DCa2+=1.2788×10-6cm2s-1) within the ZnO-Chitosan composite film. Genocchi polynomial approximation method was employed for the establishment of a precise mathematical relationship between the steady-state concentration of calcium ions and the distance from the electrode's surface. This newly developed GC/ZnO-Chitosan electrode presents a significant improvement over previously developed electrodes for calcium ions, as it enables the precise analysis of calcium ion diffusion profiles at steady-state.

Seed Treatment with Calcium Carbonate Containing Bacillus amyloliquefaciens PMB05 Powder Is an Efficient Way to Control Black Rot Disease of Cabbage

Black rot disease is a serious bacterial disease that harms vegetable crops of the Brassica genus (especially cabbage plants) worldwide. The causal agent, Xanthomonas campestris pv. campestris (Xcc), is a seed-borne pathogen that primarily infects seedlings. Previous studies suggest that the bacterial strain, Bacillus amyloliquefaciens PMB05, can intensify the plant immune responses of cabbage against black rot disease and reduce disease occurrence. In plant immunity, several reactions occur during a pathogen attack, but the elevation of calcium ion concentration in plant cells is essential in the induction of plant defense responses. Therefore, this study aims to investigate whether disease control of black rot disease in cabbage plants can be improved by integrating calcium carbonate in the formulation for preparing B. amyloliquefaciens PMB05. Firstly, we found the addition of calcium carbonate in the formulation revealed to have significantly increased the cell and endospore populations of B. amyloliquefaciens PMB05 in the fermentation liquids. To increase the convenience of disease control in the field, these fermentation liquids were converted to powder form for subsequent analysis. Results revealed that the grown seedlings from seeds, mixed with PMB05 powders, significantly intensified plant immune responses and improved black rot disease control. We further compared distinct seed treatments using one PMB05 powder to evaluate its feasibility in field application. The results demonstrated that the disease control efficacy and yield of cabbage were significantly improved in the seed treatment with the powder (SD-160C2) to 56.46% and 5.91%, respectively, at 10 weeks post transplanting. Interestingly, the seed treatment combined with a calcium-containing commercial fertilizer spraying treatment did not increase the control efficacy of black rot disease, but it significantly increased the weight of cabbages after harvest. We concluded that the seed treatment with calcium carbonate-containing Bacillus amyloliquefaciens PMB05 powder is an efficient way to control black rot disease in cabbage.

The pathological prion protein forms ionic conductance in lipid bilayer

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative pathologies characterized by the accumulation of amyloid fibrils mainly composed of the pathological isoform of the prion protein (PrPTSE). PrPTSE pre-amyloid fibrils are supposed to induce neurodegenerative lesions possibly through the alteration of membrane permeability. The effect of PrPTSE on cellular membranes has been modeled in vitro by synthetic peptides that are, however, only partially representative of PrPTSE isoforms found in vivo. In the present work we show that a synthetic membrane exposed to PrP27–30 extracted from TSE-infected hamster brains changes its permeability because of the formation of molecular pores that alter the conductance of the synthetic lipid bilayer. Synthetic membrane challenged with the recombinant prion peptide PrP90–231 shows a much lower conductance. Elevation of calcium ion concentration not only increases the current amplitude due to the action of both PrP27–30 and PrP90–231 on the membrane, but also amplifies the interaction of PrP90–231 with the lipid bilayer.

痛覚関連培養神経細胞のとう痛物質による興奮とレーザー照射による抑制

The exicitatory effects of algesic substances on cultured murine dorsal root ganglion (DRG) neurons were studied by measuring cytosolic calcium oscillations (conforcal laser scanning microscopy) and action potentials (patch-clamp whole-cell recording) in the cell body. Bradykinin, prostaglandin E2, and capsaicin evoked action potentials in the cell body. Calcium oscillations were also observed by the stimulation of the compounds. Both the action potentials elicited and the elevation of calcium ion concentration caused by bradykinin were suppressed by the irradiation of Ga-Al-As diode laser (830nm, 16.2mW). The laser irradiation may block the depolarizations via sodium ion channels and calcium ion channels.