The excitatory neurotransmitter glutamate evokes physiological responses within the astrocytic network that lead to fine morphological dynamics. However, the mechanism by which astrocytes couple glutamate sensing with cellular calcium rise remains unclear. Employing natural properties of U118-MG astrocytoma cells, we tested a possible connection between L-type voltage-gated calcium channels (Cav) and glutamate receptors. Using live confocal imaging and pharmacological inhibitors, the extension of U118-MG processes upon glutamate exposure are shown to depend mainly on extracellular calcium entry via L-type Cav's. Inhibitors of the Cav α1 protein, decreased astrocytic filopodia extension; while, gabapentinoids, ligands of the Cav's α2δ auxiliary subunit blocked all process growth. This study suggests that α2δ is the main contributor to Cav's role in glutamate-dependent filopodiagenesis. It opens new avenues of research on the role of α2δ in neuron-astrocyte glutamate signaling and neurochemical signaling at tripartite synapses.

A chemical probe (DECM-PhKA) was developed to study filopodia extension in glial cells with spatio-temporal control. Irradiating DECM-PhKA with blue light releases the neuroactive agonist phenylkainic acid with a half-lifetime of 61 seconds. The effect of rapid uncaging was demonstrated in U118-MG astrocyte cells. The agonist is released locally with high precision using an optic fiber to trigger calcium influx that leads to filopodia extension in the targeted cells. This chemical probe provides a new tool to study the contribution of kainate receptors in transduction of external signals at the single cell level using a physiologically compatible wavelength.

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BackgroundBiological processing of heavy fractions of crude oils offers less severe process conditions and higher selectivity for refining. Biochemical Processes are expected to be low demand energy processes and certainly ecofriendly.ResultsA strain of biosurfactant producing bacterium was isolated from an oil contaminated soil at Tehran refinery distillation unit. Based on selected phenotypic and genotypic characteristic including morphology, biochemical proprety, and 16 SrRNA sequencing identified as a novel strain of Bacillus cereus (JQ178332). This bacterium endures a wide range of pH, salinity and temperature. This specific strain utilizes both paraffin and anthracene as samples of aliphatic and polycyclic aromatic hydrocarbons. The ability of this bacterium to acquire all its energy and chemical requirements from Vacuum Distillation Residue (VR), as a net sample of problematic hydrocarbons in refineries, was studied. SARA test ASTM D4124-01 revealed 65.5% decrease in asphaltenic, 22.1% in aliphatics and 30.3% in Aromatics content of the VR in MSM medium. Further results with 0.9% saline showed 55% decrease in asphaltene content and 2.1% Aromatics respectively.ConclusionRemarkable abilities of this microorganism propose its application in an ecofriendly technology to upgrade heavy crude oils.

Purpose: In the brain, astrocytes are non-excitable cells that undergo rapid morphological changes when stimulated by the excitatory neurotransmitter glutamate. We developed a chemical probe to monitor how glutamate affects the density and distribution of astrocytic Ltype voltage-gated calcium channels (LTCC). Procedures: The imaging probe FluoBar1 was created from a barbiturate ligand modified with a fluorescent coumarin moiety. The probe selectivity was examined with colocalization analyses of confocal fluorescence imaging in U118-MG and transfected COS-7 cells. Living cells treated with 50 nM FluoBar1 were imaged in real time to reveal changes in density and distribution of astrocytic LTCCs upon exposure to glutamate. Results: FluoBar1 was synthesized in ten steps. The selectivity of the probe was demonstrated with immunoblotting and confocal imaging of immunostained cells expressing the CaV1.2 isoform of LTCCs proteins. Applying FluoBar1 to astrocyte model cells U118-MG allowed us to measure a 5-fold increase in fluorescence density of LTCCs upon glutamate exposure. Conclusions: Imaging probe FluoBar1 allows the real-time monitoring of LTCCs in living cells, revealing for first time that glutamate causes a rapid increase of LTCC membranar density in astrocyte model cells. FluoBar1 may help tackle previously intractable questions about LTCC dynamics in cellular events.