Calcium Signaling Pathways

The modern Western society lifestyle is characterized by a hyperenergetic, high sugar
containing food intake. Sugar intake increased dramatically during the last few decades, due to the
excessive consumption of high-sugar drinks and high-fructose corn syrup. Current evidence suggests
that high fructose intake when combined with overeating and adiposity promotes adverse metabolic
health effects including dyslipidemia, insulin resistance, type II diabetes, and inflammation. Similarly,
elevated glucocorticoid levels, especially the enhanced generation of active glucocorticoids in the
adipose tissue due to increased 11-hydroxysteroid dehydrogenase 1 (11-HSD1) activity, have been
associated with metabolic diseases. Moreover, recent evidence suggests that fructose stimulates the
11-HSD1-mediated glucocorticoid activation by enhancing the availability of its cofactor NADPH.
In adipocytes, fructose was found to stimulate 11-HSD1 expression and activity, thereby promoting
the adipogenic effects of glucocorticoids. This article aims to highlight the interconnections between
overwhelmed fructose metabolism, intracellular glucocorticoid activation in adipose tissue, and their
metabolic effects on the progression of the metabolic syndrome.

Angiogenesis and signaling through the RAS/RAF/mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK cascade have been reported to play important roles in the development of hepatocellular carcinoma (HCC). Sorafenib (Nexavar), a novel bi-aryl urea BAY 43-9006, is an orally administered multikinase inhibitor with activity against RAS/RAF kinases multikinase inhibitor with activity against RAFkinases and several receptor tyrosine kinases, including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), FLT3, Ret, and c-Kit. It is involved in angiogenic pathway and cell
proliferation. Sorafenib has demonstrated potent anti-tumor activity in in vitro studies, preclinical xenograft models of different tumor types and human clinical trials. This review summarizes the history of sorafenib from its discovery by the medicinal chemistry approach through to clinical development and ongoing trials on the combination between sorafenib and trans-arterial chemoembolization (TACE) in HCC patients.

Version in Spanish and English. Versiones en Español e Ingles.
INTRODUCTION.
  1. Living organisms can modify the limits of the habitability zone of an star by interacting with the abiotic environment of a planet in a region called the habitable zone of inhabited planets (inHZ) [1].
  2. These organisms can be considered as biological communities which behave as a single entity (holobiont) [2].
  3. Calcium is the main messenger that links physiological rhythms in microorganisms with the ecological cycles of energy of their environment [3,4]. 
  We have proposed that the response to astrophysical electromagnetism (light, heat, plasma) has an important role in the evolution of sensory receptors [5]. Calcium ions have two electric charges and it is an intracellular messenger that respond to electromagnetic fields and to the cellular membrane.  Here we extend previous computational studies [1][5] showing that calcium can play a role in climate regulation and habitability in a planet (levels of CO2, calcium carbonate, temperature and pH). We focus in the extracellular dynamics of calcium for holobionts.
 
  MATERIALS AND METHODS.
  1. We search of bibliographic resources using filters in academic data bases.
  2. We use of mathematical analogies and simple physical models (circuits, mechanical dynamical models [2]).
  3. We explore new concepts linking holobionts and rhythms in astrobiology.
 
  CONCLUSIONS.
  1. Fluctuations in the calcium levels, generated by holobionts, and coupled with cycles of rotation (circadian) and translation (circanuales) of a planet, can be able to form oscillations in habitability. 
  2. It is evolutionary advantageous for microorganisms to incorporate these rhythms in order to predict the calcium-dependent favorable phases for exploration/activation vs. the states of resting.

REFERENCES

[1] Zuluaga, J. I., Salazar, J. F., Cuartas-Restrepo, P., and Poveda, G.: The Habitable Zone of Inhabited Planets, Biogeosciences Discuss., 11, 8443-8483, doi:10.5194/bgd-11-8443-2014, 2014.

[2] Zilber-Rosenberg, I., and Rosenberg, E. (2008). Role of microorganisms in the evolution of animals and plants: the hologenome theory of evolution. FEMS Microbiol. Rev. 32, 723–735. doi: 10.1111/j.1574-6976.2008.00123

[3] Anbu P, Kang CH, Shin YJ, So JS. (2016) Formations of calcium carbonate minerals by bacteria and its multiple applications. Springerplus.Mar 1;5:250. doi: 10.1186/s40064-016-1869-2. eCollection 2016.

[4] Williams R.J.P. (2006) The evolution of calcium biochemistry. Biochimicaet BiophysicaActa1763 1139–1146

[5]Gomez JF and Restrepo (2012). Electromagnetism and magnetoreception: Detection of astrophysical events by organisms and robots. 2nd international Congress in astrobiology. Medellin, Planetario Municipal.

NOTE (26/02/2017): Accepted Abstract #5 by the Academic Committee of the 3rd International Congress of Astrobiology

Sensory hair cells rely on otoferlin as the calcium sensor for exocy-tosis and encoding of sound preferentially over the neuronal calcium sensor synaptotagmin. Although it is established that synaptotagmin cannot rescue the otoferlin KO phenotype, the large size and low solubility of otoferlin have prohibited direct biochemical comparisons that could establish functional differences between these two proteins. To address this challenge, we have developed a single-molecule colocalization binding titration assay (smCoBRA) that can quantitatively characterize full-length otoferlin from mammalian cell lysate. Using smCoBRA, we found that, although both otoferlin and synaptotagmin bind membrane fusion SNARE proteins, only otoferlin interacts with the L-type calcium channel Cav1.3, showing a significant difference between the synaptic proteins. Furthermore, otoferlin was found capable of interacting with multiple SNARE and Cav1.3 proteins simultaneously, forming a heterooligomer complex. We also found that a deafness-causing missense mutation in otoferlin attenuates binding between otoferlin and Cav1.3, suggesting that deficiencies in this interaction may form the basis for otoferlin-related hearing loss. Based on our results, we propose a model in which otoferlin acts as a calcium-sensitive scaffolding protein, localizing SNARE proteins proximal to the calcium channel so as to synchronize calcium influx with membrane fusion. Our findings also provide a molecular-level explanation for the observation that synaptotagmin and otoferlin are not functionally redundant. This study also validates a generally applicable methodology for quantitatively characterizing large, multivalent membrane proteins. exocytosis | membrane fusion | calcium | otoferlin | calcium channel

"The present study dealt with the effects of applica
tion of probiotic bacteria from the genus Lactobacillus,
which are important representatives of symbiotic
human microflora, as well as the products of their
metabolism obtained by the new method of nutritional
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Many cells use calcium signaling to carry information from the extracellular side of the plasma membrane to targets in their interior. Since virtually all cells employ a network of biochemical reactions for Ca 2+ signaling, much effort has been devoted to understand the functional role of Ca 2+ responses and to decipher how their complex dynamics is regulated by the biochemical network of Ca 2+-related signal transduction pathways. Experimental observations show that Ca 2+ signals in response to external stimuli encode information ...

Thermal analysis of hydroxyapatite formation through dry mechanochemical method has been studied. The calcium phosphate was synthesized using calcium hydroxide and di-ammonium hydrogen phosphate as the precursors. The ball milling of 1/6 ball-powder mass ratio was employed on mixtures of calcium hydroxide and di-ammonium hydrogen phosphate in three different speeds 170, 270 and 370 rpm for 15 h. As ball-milled powders were then sintered at 1150, 1250 and 1350 o C for 2 h, then subjected to TGA, XRD and FTIR for phase characterization. Calcium phosphates with ammonium are phases of the material. The ammonium is trace of phosphorus precursor. Choosing condition of the process and type of precursors determines type of reactions and its products.

The complexity of the signaling network that underlies astrocyte-synapse interactions may seem discouraging when tackled from a theoretical perspective. Computational modeling is challenged by the fact that many details remain hitherto unknown and conventional approaches to describe synaptic function are unsuitable to explain experimental observations when astrocytic signaling is taken into account. Supported by experimental evidence is the possibility that astrocytes perform genuine information processing by means of their calcium signaling and are players in the physiological setting of the basal tone of synaptic transmission. Here we consider the plausibility of this scenario from a theoretical perspective, focusing on the modulation of synaptic release probability by the astrocyte and its implications on synaptic plasticity. The analysis of the signaling pathways underlying such modulation refines our notion of tripartite synapse and has profound implications on our understanding of brain function.

Alzheimer's disease (AD) is a progressive, age-related neurodegenerative disorder which first manifests as profound memory dysfunction. The majority of cases are idiopathic, although advanced age is the greatest risk factor for AD. Recent evidence suggests that pre-fibrillar soluble amyloid-beta (Aβ) underlies an early, progressive loss of synapses that is a hallmark of AD. One of the downstream effects mediated by soluble Aβ aggregates is the hyperactivation of the phosphatase calcineurin (CaN). This important phosphatase is abundant in the nervous system and intimately involved in the mechanisms of memory as well as the immune response. Such a duality places CaN at the crux of neuroimmunomodulation processes. In the present review, we briefly summarize the role of CaN in physiological aging and discuss how CaN hyperactivity could cause the memory impairment, neuroinflammation, and neuronal death that are pathological mechanisms of AD.

Sperm-specific phospholipase C-(PLC) induces Ca 2 oscillations and egg activation when injected into mouse eggs. PLC has such a high Ca 2 sensitivity of PLC activity that the enzyme can be active in resting cells at 100 nM Ca 2 , suitable for a putative sperm factor to be introduced into the egg at fertilization (Kou-chi). In the present structure-function analysis, deletion of EF1 and EF2 of the N-terminal four EF-hand domains caused marked reduction of phosphatidylino-sitol 4,5-bisphosphate (PI(4,5)P 2)-hydrolyzing activity in vitro and loss of Ca 2 oscillation-inducing activity in mouse eggs after injection of RNA encoding the mutant. However, deletion of EF1 and EF2 or mutation of EF1 or EF2 at the x and z positions of the putative Ca 2-binding loop little affected the Ca 2 sensitivity of the PLC activity, whereas deletion of EF1 to EF3 caused 12-fold elevation of the EC 50 of Ca 2 concentration. Thus, EF1 and EF2 are important for the PLC activity, and EF3 is responsible for its high Ca 2 sensitivity. Deletion of four EF-hand domains or the C-terminal C2 domain caused complete loss of PLC activity, indicating that both regions are prerequisites for PLC activity. Screening of interactions between the C2 domain and phosphoinositides revealed that C2 has substantial affinity to PI(3)P and, to the lesser extent, to PI(5)P but not to PI(4,5)P 2 or acidic phospholip-ids. PI(3)P and PI(5)P reduced PLC activity in vitro, suggesting that the interaction could play a role for negative regulation of PLC. PLC 1 is a novel type of PLC (the enzyme that hydrolyzes membrane PI(4,5)P 2 into IP 3 and diacylglycerol). PLC is strongly noted in developmental biology because it is specifically expressed in mammalian sperm (1) and is capable of inducing repetitive increase in [Ca 2 ] i and subsequent early embryonic development when expressed in mouse eggs by injection of RNA encoding PLC (1–3). At fertilization of mammals , evidence indicates that a cytosolic sperm factor is introduced into the ooplasm upon sperm-egg fusion and induces Ca 2 oscillations (4, 5), which are due to Ca 2 release from the endoplasmic reticulum mainly through the IP 3 receptor (6) and are a pivotal signal for egg activation (5). Ca 2 oscillations similar to those at fertilization are produced by PLC expressed in a mouse egg at an estimated level comparable with the content in a single mouse sperm (1, 2). Injection of recombinant PLC into mouse eggs induces Ca 2 oscillations as well (7). The Ca 2 oscillation-inducing activity of sperm extract (4, 8) is lost when the extract is pretreated with an antibody against PLC (1). Thus, PLC is a strong candidate for the sperm-derived Ca 2 oscillation-inducing protein. PLC possesses biochemically interesting characteristics. It is composed of four EF-hand domains in the N terminus, catalytic X and Y domains, and a C2 domain in the C terminus (1) (Fig. 1A) common to other types of PLC, but PLC lacks the N-terminal PH domain found in PLC,- ,-, and-. PH domain of PLC,-, or-binds to PI(3)P, PI(3,4,5)P 3 , or PI(4,5)P 2 , respectively (9 –11). The PH and C2 domains of PLC also interact with the G protein subunits G and G q , respectively, for activation of PLC (12, 13). PLC is phosphorylated at the tyrosine residues 771, 783, and 1254 in response to growth factor stimulation leading to activation of PLC (9 –11). As for PLC, which lacks the PH domain, there is no prediction about the domain responsible for binding to phosphoinositides and for enzymatic activation. PLC has domain features similar to those of PLC except for the PH domain (Fig. 1A). PLC is suggested to be regulated by Ca 2 because PLC1 has Ca 2-binding sites in not only the EF-hand domains but also in the X and Y domains and the C2 domain (11). We have recently shown (7) that the PI(4,5)P 2-hydrolyzing activity of recombinant PLC is 100-fold more sensitive to Ca 2 than that of PLC1 and is 70% maximal at 100 nM [Ca 2 ], which is usually the basal [Ca 2 ] i of cells. Recombinant PLC has 20-fold higher Ca 2 oscillation-inducing activity than PLC1 (7). Thus, PLC possesses remarkable properties that are favorable for the sperm factor to initiate (7) and maintain (3) Ca 2 oscillations via continuously produced IP 3. Using mutational analysis in the present study, we addressed which domains of PLC are responsible for the Ca 2-sensitive PLC activity in vitro, Ca 2 oscillation-inducing activity in mouse eggs, and phosphoinositide binding activity in vitro and the effect of phosphoinositide binding activity on the PLC activity. We focused on four N-terminal EF-hand domains because they are likely to be Ca 2-binding sites and could be critical for the high Ca 2 sensitivity. We also focused on the C2 domain, as three Ca 2-binding sites are predicted in the C2

Salicylic acid (SA) is one of the key hormonal factors determining the fate of plants exposed to stressful conditions, which is naturally found in plants and shown to be involved in the plant defense-related actions against infection by various pathogens. Recently, intracellular SA receptors were finally identified after a long survey of SA-binding proteins. In this chapter, the modes of both the short-and long-distance signaling events involving the actions of SA, a defense-related key signaling molecule, are compared by covering both the biochemical and electrophysiological views. Here, two distinct models for local SA perception and signaling mechanisms involved in the extracellular and intracellular paths (referred to as models i and ii), and the three different models for long-distance signaling mediated by SA are reviewed (referred to as models iii–v). The local SA signaling events can be attributed to (i) the extracellular SA perception model in which reactions between SA and apoplastic proteins result in acute oxidative burst 23 followed by internalization of the derived signals via activation of calcium channels, and/or (ii) intracellular SA perception mechanism by which the action and life cycle of NPR1 protein are determined depending on the concentration of SA in both the infected cells and neighboring cells. On the other hand, the long-distance SA action could be attributed to three different modes, namely, (iii) local increase in SA followed by phloem transport of SA, (iv) systemic propagation of SA-derived mobile signals with both electrical and chemical natures without direct movement of SA, and (v) synergistic propagation of both SA and derived signals through the tissues and phloem. We view here that the long-distance SA signaling events (models iii–v) inevitably involve the mechanisms described in the local signaling models (models i and ii) as the key pieces of the puzzle.

During the development of the vertebrate feeding apparatus, a variety of complicated cellular and molecular processes participate in the formation and integration of individual skeletal elements. The molecular mechanisms regulating the formation of skeletal primordia and their development into specific morphological structures are tightly controlled by a set of interconnected signalling pathways. Some of these pathways, such as Bmp, Hedgehog, Notch and Wnt, are long known for their pivotal roles in craniofacial skeletogenesis. Studies addressing the functional details of their components and downstream targets, the mechanisms of their interactions with other signals as well as their potential roles in adaptive morphological divergence, are currently attracting considerable attention. An increasing number of signalling pathways that had previously been described in different biological contexts have been shown to be important in the regulation of jaw skeletal development and morphogenesis. In this review, I provide an overview of signalling pathways involved in trophic skeletogenesis emphasizing studies of the most species-rich group of vertebrates, the teleost fish, which through their evolutionary history have undergone repeated episodes of spectacular trophic diversification.

cGMP is a second messenger widely used in the nervous system and other tissues. One of the major effectors for cGMP is the serine/threonine protein kinase, cGMP-dependent protein kinase (PKG), which catalyzes the phosphorylation of a variety of proteins including ion channels. Previously, it has been shown that the cGMP-PKG signaling pathway inhibits Ca 2+ currents in rat vestibular hair cells and chromaffin cells. This current allegedly flow through voltage-gated Ca V 1.3L-type Ca 2+ channels, and is important for controlling vestibular hair cell sensory function and catecholamine secretion, respectively. Here, we show that native L-type channels in the insulin-secreting RIN-m5F cell line, and recombinant Ca V 1.3 channels heterologously expressed in HEK-293 cells, are regulatory targets of the cGMP-PKG sig-naling cascade. Our results indicate that the Ca V 1 ion-conducting subunit of the Ca V 1.3 channels is highly expressed in RIN-m5F cells and that the application of 8-Br-cGMP, a membrane-permeable analogue of cGMP, significantly inhibits Ca 2+ macroscopic currents and impair insulin release stimulated with high K +. In addition, KT-5823, a specific inhibitor of PKG, prevents the current inhibition generated by 8-Br-cGMP in the heterologous expression system. Interestingly, mutating the putative phosphoryla-tion sites to residues resistant to phosphorylation showed that the relevant PKG sites for Ca V 1.3 L-type channel regulation centers on two amino acid residues, Ser793 and Ser860, located in the intracellular loop connecting the II and III repeats of the Ca V 1 pore-forming subunit of the channel. These findings unveil a novel mechanism for how the cGMP-PKG signaling pathway may regulate Ca V 1.3 channels and contribute to regulate insulin secretion.

A new paradigm has recently emerged in brain science whereby communications between glial cells and neuron-glia interactions should be considered together with neurons and their networks to understand higher brain functions. In particular, astrocytes, the main type of glial cells in the cortex, have been shown to communicate with neurons and with each other. They are thought to form a gap-junction-coupled syncytium supporting cell-cell communication via propagating Ca 2+ waves. An identified mode of propagation is based on cytoplasm-to-cytoplasm transport of inositol trisphosphate (IP 3 ) through gap junctions that locally trigger Ca 2+ pulses via IP 3 -dependent Ca 2+ -induced Ca 2+ release. It is, however, currently unknown whether this intracellular route is able to support the propagation of long-distance regenerative Ca 2+ waves or is restricted to short-distance signaling. Furthermore, the influence of the intracellular signaling dynamics on intercellular propagation remains to be understood. In this work, we propose a model of the gap-junctional route for intercellular Ca 2+ wave propagation in astrocytes. Our model yields two major predictions. First, we show that long-distance regenerative signaling requires nonlinear coupling in the gap junctions. Second, we show that even with nonlinear gap junctions, long-distance regenerative signaling is favored when the internal Ca 2+ dynamics implements frequency modulation-encoding oscillations with pulsating dynamics, while amplitude modulation-encoding dynamics tends to restrict the propagation range. As a result, spatially heterogeneous molecular properties and/or weak couplings are shown to give rise to rich spatiotemporal dynamics that support complex propagation behaviors. These results shed new light on the mechanisms implicated in the propagation of Ca 2+ waves across astrocytes and the precise conditions under which glial cells may participate in information processing in the brain.

We studied the effects of mono-, di-, tri-, and hexamers of glucosamine (GlcN) and N-acetylglucosamine (GlcNAc) on oxidative and calcium signals in transgenic tobacco suspension culture (Nicotiana tabacum L. cv. Bright Yellow-2, cell line CST-1) expressing aequorin. Addition of (GlcN)n to the cells induced an immediate oxidative burst monitored by superoxide-specific chemiluminescence of CLA (CLA-CL). The superoxide generated by (GlcN)n was converted to hydrogen peroxide, causing a transient increase in cytosolic Ca2+ concentration ([Ca2+]c) which was monitored by ([Ca2+]c-dependent luminescence of aequorin. The longer the polymer of (GlcN)n the greater the effect. The (GlcN)n-dependent CLA-CL in the culture was inhibited by a peroxidase inhibitor, but not by a NADPH oxidase inhibitor. The (GlcN)n-dependent CLA-CL was also observed in the extracellularly excreted peroxidase preparation and also in horseradish peroxidase reaction mixture. We have previously obtained similar results using salicylic acid and aromatic amines. Addition of (GlcNAc)n also resulted in an elevation of [Ca2+]c. No superoxide generation preseding [Ca2+]c elevation was detected using CLA, but gradual accumulation of superoxide signal was detected with electron spin resonance spectroscopy using Tiron as a spin trapper. No effect of GlcNAc monomer and oligomers shorter than hexamer on [Ca2+]c elevation or superoxide generation was observed.
In various plants, generation of reactive oxygen species (ROS) is one of the important early events in the active defense against pathogens. ROS can be induced by pathogen invation or treatment with elicitors....

Effects of exogenous calcium chloride (CaCl 2 ) (20 mM) on photosynthetic gas exchange, photosystem II photochemistry, and the activities of antioxidant enzymes in tobacco plants under high temperature stress (43 • C for 2 h) were investigated. Heat stress resulted in a decrease in net photosynthetic rate (P n ), stomatal conductance as well as the apparent quantum yield (AQY) and carboxylation efficiency (CE) of photosynthesis. Heat stress also caused a decrease of the maximal photochemical efficiency of primary photochemistry (F v /F m ). On the other hand, CaCl 2 application improved P n , AQY, and CE as well as F v /F m under high temperature stress. Heat stress reduced the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD), whereas the activities of these enzymes either decreased less or increased in plants pretreated with CaCl 2 ; glutathione reductase (GR) activity increased under high temperature, and it increased more in plants pretreated with CaCl 2 . There was an obvious accumulation of H 2 O 2 and O 2 − under high temperature, but CaCl 2 application decreased the contents of H 2 O 2 and O 2 − under heat stress conditions. Heat stress induced the level of heat shock protein 70 (HSP70), while CaCl 2 pretreatment enhanced it. These results suggested that photosynthesis was improved by CaCl 2 application in heat-stressed plants and such an improvement was associated with an improvement in stomatal conductance and the thermostability of oxygen-evolving complex (OEC), which might be due to less accumulation of reactive oxygen species.

Cell surface hemichannels (HCs) composed of different connexin (Cx) types are present in diverse cells and their possible role on FGF-1–induced cellular responses remains unknown. Here, we show that FGF-1 transiently (4–14 h, maximal at 7 h) increases the membrane permeability through HCs in HeLa cells expressing Cx43 or Cx45 under physiological extracellular Ca2+/Mg2+ concentrations. The effect does not occur in HeLa cells expressing HCs constituted of Cx26 or Cx43 with its C-terminus truncated at aa 257, or in parental nontransfected HeLa cells. The increase in membrane permeability is associated with a rise in HC levels at the cell surface and a proportional increase in HC unitary events. The response requires an early intracellular free Ca2+ concentration increase, activation of a p38 MAP kinase-dependent pathway, and a regulatory site of Cx subunit C-terminus. The FGF-1–induced rise in membrane permeability is also associated with a late increase in intracellular free Ca2+ conc...

Notwithstanding major advances in psychotherapeutics, their efficacy and specificity remain limited. The slow onset of beneficial outcomes and numerous adverse effects of widely used medications remain of chief concern, warranting in-depth studies. The majority of frontline therapies are thought to enhance the endogenous monoaminergic drive, to initiate a cascade of events leading to lasting functional and structural plasticity. The latter also involves alterations in trophic factor signalling, including brain-derived neurotrophic factor (BDNF), NGF (nerve growth factors), vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF2), glial cell-derived neurotrophic factor (GDNF), and others. In several major mental disorders, emerging data suggest protective and restorative effects of trophic factors in preclinical models, when applied on their own. Antidepressant outcomes of VGF and FGF2, for instance, were shown in experimental animals, while BDNF and GDNF prove useful in the treatment of addiction, schizophrenia, and autism spectrum disorders. The main challenge with the effective translation of these and other findings in the clinic is the knowledge gap in action mechanisms with potential risks, as well as the lack of effective platforms for validation under clinical settings. Herein, we review the state-of-the-art and advances in the therapeutic use of trophic factors in several major neuropsychiatric disorders.

Drought is a ubiquitous abiotic factor that severely impedes growth and development of horticulture crops. The challenge postured by global climate change is the evolution of drought-tolerant cultivars that could cope with concurrent stress. Hence, in this study, biochemical, physiological and transcriptome analysis were investigated in drought-treated grapevine leaves. The results revealed that photosynthetic activity and reducing sugars were significantly diminished which were positively correlated with low stomatal conductance and CO 2 exchange in drought-stressed leaves. Further, the activities of superoxide dismutase, peroxidase, and catalase were significantly actuated in the drought-responsive grapevine leaves. Similarly, the levels of abscisic acid and jasmonic acid were also significantly increased in the drought-stressed leaves. In transcriptome analysis, 12,451 differentially expressed genes (DEGs) were annotated, out of which 8021 DEGs were up-regulated and 4430 DEGs were down-regulated in response to drought stress. In addition, the genes encoding pathogen-associated molecular pattern (PAMP) triggered immunity (PTI), including calcium signals, protein phosphatase 2C, calcineurin B-like proteins, MAPKs, and phosphorylation (FLS2 and MEKK1) cascades were up-regulated in response to drought stress. Several genes related to plant-pathogen interaction pathway (RPM1, PBS1, RPS5, RIN4, MIN7, PR1, and WRKYs) were also found up-regulated in response to drought stress. Overall the results of present study showed the dynamic interaction of DEG in grapevine physiology which provides the premise for selection of defense-related genes against drought stress for subsequent grapevine breeding programs.

This review article was prepared based on our recent publications on cold-responsive plant calcium signaling released in Japanese, after a major revision updating the topics. Plants respond to various environmental stimuli such as acute changes in temperature, by activating each component in the signaling cascade such as Ca2+ channels, required for adaptations to changing environments. In this study, the effects of naturally existing rare earth elements) added as chloride salts, on Ca2+ influx through ion channels, induced by two different temperature stresses, namely cold and heat shocks were tested using suspension-cultured transgenic tobacco cell line (BY-2) expressing aequorin, a Ca2+-sensitive luminescent protein in its cytosol. Action of Al3+ , a putative TPC1-type channel inhibitor was also examined. Based on the results obtained, the nature of temperature-sensitive Ca2+ influx was discussed.

Resealing of tears in the sarcolemma of myofibers is a necessary step in the repair of muscle tissue. Recent work suggests a critical role for dysferlin in the membrane repair process, and that mutations in dysferlin are responsible for limb girdle muscular dystrophy 2B and Miyoshi myopathy. Beyond membrane repair, dysferlin has been linked to SNARE mediated exocytotic events including cytokine release and acid sphingomyelinase secretion. H o w e ve r , i t i s u n c l e a r w h e t h e r d ys f e r l i n r e gu l a t e s S N A R E m e d i a t e d me m b r a n e f u s i o n. In this study we demonstrate a direct interaction between dysferlin and the SNARE proteins syntaxin 4 and SNAP-23. In addition, analysis of FRET and in vitro reconstituted lipid mixing assays indicate that dysferlin accelerates syntaxin 4/SNAP-23 heterodimer formation and SNARE mediated lipid mixing in a calcium sensitive manner. These results support a function for dysferlin as a calcium sensing SNARE effector for membrane fusion events.

Calcium influx through store-operated Ca 2+ entry (SOCE), mediated by STIM-operated Orai channels, is crucial for many cellular functions. To dissect the molecular mechanisms underlying the process of STIM-Orai activation and identify regulators that modify this process, ratiometric imaging of SOCE responses in HEK cells overexpressing STIM and Orai is a routinely used method. Here we describe one commonly used procedure of monitoring SOCE activity with a ratiometric membrane-permeable dye fura-2-AM. Other ratiometric indicators suitable for SOCE measurements are also discussed.

ABSTRACT
Duodenal switch surgery causes malabsorption through biliopancreatic diversion that bypasses the duodenum and proximal jejunum (Fig 1). Hypovitaminosis D and hypocalcemia may result and lead to secondary hyperparathyroidism (SHPT). Little is published regarding refractory SHPT in obese patients managed by bariatric surgery.  We present a case of SHPT refractory to vitamin D repletion that responded favorably to treatment with the calcimimetic agent cinacalcet.  Though cinacalcet is used to manage SHPT due to chronic kidney disease, we are unaware of any reports documenting cinacalcet as therapy for SHPT caused by bariatric surgery.

Cations of Al and rare earth elements (REEs) are phyto-toxic.  The toxicity of such cations has been summarized as followings: (1) metal cations induce the production of superoxide (O2-) in plant cells; (2) the metal cations with higher valence induce greater oxidative burst (OXB); (3) with higher ion valence, the concentration required for maximal response is minimized; (4) the induced OXB is sensitive to inhibitors of NADPH oxidase.  To date, non-redox metal cations such as those of Al, La, Ce, and Gd, have been shown to induce OXB. It has been shown that Zn2+ inhibits the REE-induced OXB. Zn is normally present in plants at high level, and its deficiency is one of the most widespread micro-nutrient deficiencies in plants, causing severe reductions in crop production.  Increasing studies indicate that oxidative damage to plants caused by reactive oxygen species (ROS) results from a deficiency of Zn. A hypothetical model explains that the O2- generating activity of NADPH oxidase is sensitive to Zn2+ , thus the REE-dependent stimulation could be inhibited or retarded by Zn2+. In this study, we tested the effect of Zn2+ supplementation on REE-induced OXB in tobacco cell culture, measured with the O2- specific chemiluminescence (CL) of a Cypridina luciferin analog (CLA). CLA-CL specifically indicates the generation of O2- and singlet oxygen (1O2) with a lesser extent, but not that of other ROS. Here, the mode of Zn action against the REE-induced OXB was assessed with Lineweaver-Burk kinetics and possible eco-physiological roles for Zn in interaction with other metal cations in plants are discussed.

Because rare earth elements (REEs) are not present at high concentrations in the normal environments surrounding living organisms, the biological roles of REEs had not been intensively tested to date. In this article, the ongoing studies on the biology and biochemistry of REEs applied to growing plants and plant cells are reviewed.

Salts at high concentrations may cause oxidative damage to plant cells since many studies indicated the involvement of reactive oxygen species in salt-stress response. Recently, we have demonstrated that treatment of tobacco (Nicotiana ta-bacum) cell suspension culture with various salts result in an immediate burst of superoxide production via activation of NADPH oxidase by ions of alkali metals (Li+ , Na+, K+), alkali earth metals (Mg2+ , Ca2+) or lanthanides (La3+, Gd3+). In this study, we tested the effect of extracellular supplementation of Zn2+ and Mn2+ on the cation-induced oxidative burst in tobacco cell suspension culture, measured with a superoxide-specific Cypridina luciferin-derived chemiluminescent reagent. Extracellular supplementation of Zn2+ and Mn2+ inhibited the generation of superoxide in response to addition of salts. Although both Zn2+ and Mn2+ inhibited the salt-induced generation of superoxide, the modes of inhibition by those ions seemed to be different since Mn2+ simply inhibited total production of superoxide while Zn2+ inhibited the early phase of superoxide production and induced the slow release of superoxide. Roles of Mn2+ and Zn2+ in protection of plant cells from salt stress, as an effective superoxide scavenger and an effective inhibitor of plasma membrane-bound NADPH oxidase, respectively, are discussed.