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Decoding the spontaneous in vivo Ca2plus oscillations in zebrafish brain neurons

100%
Gupta R. K., Wasilewska I., Palkchevska O., Kuznicki J.
Acta Neurobiologiae Experimentalis
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2019
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tom 79
|
nr Suppl.1
INTRODUCTION: Neurons code sensory information in Ca2+ spiking trains at discrete points in time and facilitate synaptic plasticity and synchronicity in the neurons. Ca2+ can enter the cytoplasm through gated ion channels. One of the regulatory mechanisms of Ca2+ homeostasis in neurons is Store-operated Ca2+ entry (nSOCE). When Ca2+ is depleted from the endoplasmic reticulum (ER: a major store of Ca2+), the decreased level of Ca2+ is sensed by STIM proteins (ER residents), which then oligomerize and interact with Ca2+ channels at the plasma membrane. This leads to Ca2+ influx and refilling ER with these ions by Ca2+‑ATPase. Analysis of parameters of the neuronal spontaneous Ca2+ oscillations in vivo and those in response to the external stimuli. Zebrafish larva is an exceptional model for whole‑brain functional imaging. However, the mechanisms underlying the spontaneous neuronal Ca2+ activity patterns, and their biological relevance, remain elusive. METHOD(S): Using Lightsheet Microscopy, we performed in vivo imaging of transgenic fish expressing GCaMP5G (a genetically encoded Ca2+ probe) under the neuronal promoter (Tg(elavl3: GCaMP5). The parameters of Ca2+ oscillations, such as the interspike intervals (ISI) and the Ca2+ amplitudes, were analyzed in neuronal somata of the three different regions of the brain (optic tectum (OT), cerebellum (Cereb), and inferior olive (IO)) of transgenic (TG), wild-type (WT), and stim2b‑/‑ zebrafish lines. RESULTS: Using MATLAB algorithms, we quantified the differences in Ca2+ oscillations patterns between regions in the brain neurons and showed that Ca2+ oscillations change significantly in stim2b‑/‑ fish. ISI was reduced, and Ca2+ amplitude was increased in stim2b‑/‑ as compared to transgenic WT in fish treated with a high concentration of Ca2+. CONCLUSIONS: This Ca2+ spiking trains modulation by Stim2b protein suggests its role in attenuation of Ca2+ buffering.
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Stim2 role in response to oxidative stress

100%
Wasilewska I., Palchevska O., Gupta R. K., Kuznicki J.
Acta Neurobiologiae Experimentalis
|
2019
|
tom 79
|
nr Suppl.1
INTRODUCTION: STIM1 and STIM2 proteins are calcium sensors residing in the ER. They are involved in the regulation of SOCE (Store-Operated Calcium Entry) and take part in Ca2+ homeostasis and signaling. They participate in the regulation of numerous processes such as genes expression, neurotransmission, and neuronal morphology. STIM1 is also sensitive to redox state and may regulate functions of mitochondria. STIM2 is highly expressed in the neuronal tissue and was shown to be involved in processes leading to neurodegeneration. Oxidative stress and abnormal activity of mitochondria are frequently proposed to be a part of the mechanism that leads to the neurodegeneration. AIM(S): We aim to check the role of Stim2b zebrafish isoform in the activity of mitochondria, and its sensitivity to redox state. METHOD(S): Wild-type and stim2b‑/‑ zebrafish are being used in the experiments and oxidative stress is induced by 2 mM H2O2 treatment of 5dpflarvae. Thesefish lines express, specifically in neurons, a genetically encoded Ca2+ probe – GCaMP5G – that allows us to track changes in Ca2+ levels in response to oxidative stress. We use state‑of‑the‑art techniques of in vivo Ca2+ imaging using lightsheet microscopy and qPCR to analyze gene expression. RESULTS: We found that expression of genes (like catalase), that are known to be involved in response to the oxidative stress, was different in stim2b‑/‑ fish as compared to wild‑type in untreated larvae. mRNA level of catalase remains elevated in mutants also after oxidative stress induction. CONCLUSIONS: These data indicate that Stim2b might be involved in the brain response to oxidative stress. However, calcium imaging data, which are now being collected in vivo, are needed to confirm this hypothesis.
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Influence of particle size on physical and sensory attributes of mango pulp powder

88%
Sharma M., Kadam D. M., Chadha S., Wilson R. A., Gupta R. K.
International Agrophysics
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2013
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tom 27
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nr 3
4

Enhancing effects of 24-epibrassinolide and Putrescine on the antioxidant capacity and free radical scavenging activity of Raphanus sativus seedlings under Cu ion stress

76%
Choudhary S. P., Bhardwaj R., Gupta B. D., Dutt P., Gupta R. K., Kanwar M., Biondi S.
Acta Physiologiae Plantarum
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2011
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tom 33
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nr 4
The present investigation recorded significant restoration of seedling growth (root length, shoot length and fresh weight) upon application of 24-epibrassinolide (EBL) and putrescine (Put) to 7-day-old seedlings of Raphanus sativus L. cv. Pusa chetki grown under copper (Cu) ion stress. EBL and Put with/or without Cu ion treated seedlings showed increased titers of ascorbic acid, total phenols and proline when compared with Cu-stressed seedlings. Differential responses in the activities of guaiacol peroxidase (GPOX) and catalase (CAT) were noted for EBL and Put alone or with/or without Cu ion treatment. Decreased activities of glutathione reductase (GR) and superoxide dismutase (SOD) noted for EBL and Put alone were observed to enhance significantly when applied in combination with Cu ion solution. A remarkable decrease in malondialdehyde contents was observed in seedlings treated with EBL and Put alone and with/or without Cu ion stress. Enhanced free radical scavenging activities were also recorded for seedlings given EBL and Put alone or in combination over Cu ion stressed seedlings. Maximum DPPH activity was observed in seedlings treated with Put and EBL 10⁻⁹ M + Put. Significant enhancements in deoxyribose and reducing power activities were too recorded for Put, EBL and Put + 10⁻⁹ M EBL treatments. Improved seedling growth, antioxidant levels (ascorbic acid, total phenols and proline) and enzymic (GPOX, CAT, SOD and GR) activities and free radical scavenging capacities along with reduced membrane damage in seedlings given EBL and Put with/or without Cu stress suggests significant and positive interactions of EBL and Put in alleviating the Cu ion induced oxidative damage in radish seedlings.
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