Noninvasive In Planta Live Measurements of H2O2 and Glutathione Redox Potential with Fluorescent roGFPs-Based Sensors.

In this protocol, we present a noninvasive in planta bioimaging technique for the analysis of hydrogen peroxide (H2O2) and glutathione redox potential in adult Arabidopsis thaliana plants. The technique is based on the use of stereo fluorescence microscopy to image A. thaliana plants expressing the two genetically encoded fluorescent sensors roGFP2-Orp1 and Grx1-roGFP2. We provide a detailed step-by-step protocol for performing low magnification imaging with mature plants grown in soil or hydroponic systems. This protocol aims to serve the scientific community by providing an accessible approach to noninvasive in planta bioimaging and data analysis.

Rapid alkalinization factor 22 has a structural and signalling role in root hair cell wall assembly.

Pressurized cells with strong walls make up the hydrostatic skeleton of plants. Assembly and expansion of such stressed walls depend on a family of secreted RAPID ALKALINIZATION FACTOR (RALF) peptides, which bind both a membrane receptor complex and wall-localized LEUCINE-RICH REPEAT EXTENSIN (LRXs) in a mutually exclusive way. Here we show that, in root hairs, the RALF22 peptide has a dual structural and signalling role in cell expansion. Together with LRX1, it directs the compaction of charged pectin polymers at the root hair tip into periodic circumferential rings. Free RALF22 induces the formation of a complex with LORELEI-LIKE-GPI-ANCHORED PROTEIN 1 and FERONIA, triggering adaptive cellular responses. These findings show how a peptide simultaneously functions as a structural component organizing cell wall architecture and as a feedback signalling molecule that regulates this process depending on its interaction partners. This mechanism may also underlie wall assembly and expansion in other plant cell types.

Plant Ca2+-ATPases: From biochemistry to signalling.

Calcium (Ca2+)-ATPases are ATP-dependent enzymes that transport Ca2+ ions against their electrochemical gradient playing the fundamental biological function of keeping the free cytosolic Ca2+ concentration in the submicromolar range to prevent cytotoxic effects. In plants, type IIB autoinhibited Ca2+-ATPases (ACAs) are localised both at the plasma membrane and at the endomembranes including endoplasmic reticulum (ER) and tonoplast and their activity is primarily regulated by Ca2+-dependent mechanisms. Instead, type IIA ER-type Ca2+-ATPases (ECAs) are present mainly at the ER and Golgi Apparatus membranes and are active at resting Ca2+. Whereas research in plants has historically focused on the biochemical characterization of these pumps, more recently the attention has been also addressed on the physiological roles played by the different isoforms. This review aims to highlight the main biochemical properties of both type IIB and type IIA Ca2+ pumps and their involvement in the shaping of cellular Ca2+ dynamics induced by different stimuli.

Widely spaced and divergent inverted repeats become a potent source of chromosomal rearrangements in long single-stranded DNA regions.

DNA inverted repeats (IRs) are widespread across many eukaryotic genomes. Their ability to form stable hairpin/cruciform secondary structures is causative in triggering chromosome instability leading to several human diseases. Distance and sequence divergence between IRs are inversely correlated with their ability to induce gross chromosomal rearrangements (GCRs) because of a lesser probability of secondary structure formation and chromosomal breakage. In this study, we demonstrate that structural parameters that normally constrain the instability of IRs are overcome when the repeats interact in single-stranded DNA (ssDNA). We established a system in budding yeast whereby >73 kb of ssDNA can be formed in cdc13-707fs mutants. We found that in ssDNA, 12 bp or 30 kb spaced Alu-IRs show similarly high levels of GCRs, while heterology only beyond 25% suppresses IR-induced instability. Mechanistically, rearrangements arise after cis-interaction of IRs leading to a DNA fold-back and the formation of a dicentric chromosome, which requires Rad52/Rad59 for IR annealing as well as Rad1-Rad10, Slx4, Msh2/Msh3 and Saw1 proteins for nonhomologous tail removal. Importantly, using structural characteristics rendering IRs permissive to DNA fold-back in yeast, we found that ssDNA regions mapped in cancer genomes contain a substantial number of potentially interacting and unstable IRs.

Current Methods to Unravel the Functional Properties of Lysosomal Ion Channels and Transporters.

A distinct set of channels and transporters regulates the ion fluxes across the lysosomal membrane. Malfunctioning of these transport proteins and the resulting ionic imbalance is involved in various human diseases, such as lysosomal storage disorders, cancer, as well as metabolic and neurodegenerative diseases. As a consequence, these proteins have stimulated strong interest for their suitability as possible drug targets. A detailed functional characterization of many lysosomal channels and transporters is lacking, mainly due to technical difficulties in applying the standard patch-clamp technique to these small intracellular compartments. In this review, we focus on current methods used to unravel the functional properties of lysosomal ion channels and transporters, stressing their advantages and disadvantages and evaluating their fields of applicability.

Identification of the Arabidopsis Calmodulin-Dependent NAD+ Kinase That Sustains the Elicitor-Induced Oxidative Burst.

NADP(H) is an essential cofactor of multiple metabolic processes in all living organisms, and in plants, NADP(H) is required as the substrate of Ca2+-dependent NADPH oxidases, which catalyze a reactive oxygen species burst in response to various stimuli. While NADP+ production in plants has long been known to involve a calmodulin (CaM)/Ca2+-dependent NAD+ kinase, the nature of the enzyme catalyzing this activity has remained enigmatic, as has its role in plant physiology. Here, we used proteomic, biochemical, molecular, and in vivo analyses to identify an Arabidopsis (Arabidopsis thaliana) protein that catalyzes NADP+ production exclusively in the presence of CaM/Ca2+ This enzyme, which we named NAD kinase-CaM dependent (NADKc), has a CaM-binding peptide located in its N-terminal region and displays peculiar biochemical properties as well as different domain organization compared with known plant NAD+ kinases. In response to a pathogen elicitor, the activity of NADKc, which is associated with the mitochondrial periphery, contributes to an increase in the cellular NADP+ concentration and to the amplification of the elicitor-induced oxidative burst. Based on a phylogenetic analysis and enzymatic assays, we propose that the CaM/Ca2+-dependent NAD+ kinase activity found in photosynthetic organisms is carried out by NADKc-related proteins. Thus, NADKc represents the missing link between Ca2+ signaling, metabolism, and the oxidative burst.

Spontaneous Heterotopic Triplet Pregnancy with a Two Viable Intrauterine Embryos and an Ectopic One with Right Tubal Rupture.

Heterotopic pregnancy (HP) is defined as the simultaneous development of an intra- and an extra uterine gestation. The occurrence of a spontaneous triplet HP is an exceptionally rare medical condition. We report the case of a young woman with spontaneous heterotopic triplets at 8 weeks of gestation, with a misdiagnosis of topic twins and acute appendicitis. The ectopic tubal pregnancy was ruptured and a salpingectomy was performed by laparotomy. The intrauterine pregnancy progressed uneventfully. The two healthy babies were delivery by cesarean section at 36 ± 2 weeks of gestation. Heterotopic triplets with ruptured tubal ectopic pregnancy represent a special diagnostic and therapeutic challenge for the obstetrician. A high rate of clinical suspicion and timely treatment by laparotomy or laparoscopy can preserve the intrauterine gestation with a successful outcome of the pregnancy.

A gravidez heterotópica é definida como o desenvolvimento simultâneo de uma gestação intra- e extra-uterina. A ocorrência de gravidez tripla heterotópica espontânea é uma condição médica excepcionalmente rara. Relatamos o caso de uma jovem com gravidez tripla espontânea, às 8 semanas de gestação, com um diagnóstico errôneo de gêmeos tópicos e apendicite aguda. A gravidez tubária ectópica estava rota e uma salpingectomia foi realizada por laparotomia. A gravidez intrauterina progrediu sem intercorrências. Os bebês nasceram saudáveis por cesariana realizada às 36 semanas de gestação. A gravidez de heterotópicos com ectopia e rotura tubária é um desafio diagnóstico e terapêutico. Um alto índice de suspeita e tratamento oportuno por laparotomia ou laparoscopia podem preservar a gestação intrauterina com um resultado bem sucedido da gravidez tópica.

Spontaneous heterotopic triplet pregnancy with a two viable intrauterine embryos and an ectopic one with right tubal rupture / Gravidez heterópica tripla espontânea com dois embriões intrauterinos viáveis e um ectópico com ruptura da tuba uterina direita

Abstract Heterotopic pregnancy (HP) is defined as the simultaneous development of an intra- and an extra uterine gestation. The occurrence of a spontaneous triplet HP is an exceptionally rare medical condition. We report the case of a young woman with spontaneous heterotopic triplets at 8weeks of gestation, with amisdiagnosis of topic twins and acute appendicitis. The ectopic tubal pregnancy was ruptured and a salpingectomy was performed by laparotomy. The intrauterine pregnancy progressed uneventfully. The two healthy babies were delivery by cesarean section at 36 ± 2 weeks of gestation. Heterotopic triplets with ruptured tubal ectopic pregnancy represent a special diagnostic and therapeutic challenge for the obstetrician. A high rate of clinical suspicion and timely treatment by laparotomy or laparoscopy can preserve the intrauterine gestation with a successful outcome of the pregnancy.

Resumo A gravidez heterotópica é definida como o desenvolvimento simultâneo de uma gestação intra- e extra-uterina. A ocorrência de gravidez tripla heterotópica espontânea é uma condição médica excepcionalmente rara. Relatamos o caso de uma jovem com gravidez tripla espontânea, às 8 semanas de gestação, com um diagnóstico errôneo de gêmeos tópicos e apendicite aguda. A gravidez tubária ectópica estava rota e uma salpingectomia foi realizada por laparotomia. A gravidez intrauterina progrediu sem intercorrências. Os bebês nasceramsaudáveis por cesariana realizada às 36 semanas de gestação.Agravidez de heterotópicos comectopia e rotura tubária é umdesafio diagnóstico e terapêutico.Umalto índice de suspeita e tratamento oportuno por laparotomia ou laparoscopia podem preservar a gestação intrauterina com um resultado bem sucedido da gravidez tópica.

Identification of Novel Inhibitors of Auxin-Induced Ca2+ Signaling via a Plant-Based Chemical Screen.

Many signal perception mechanisms are connected to Ca2+-based second messenger signaling to modulate specific cellular responses. The well-characterized plant hormone auxin elicits a very rapid Ca2+ signal. However, the cellular targets of auxin-induced Ca2+ are largely unknown. Here, we screened a biologically annotated chemical library for inhibitors of auxin-induced Ca2+ entry in plant cell suspensions to better understand the molecular mechanism of auxin-induced Ca2+ and to explore the physiological relevance of Ca2+ in auxin signal transduction. Using this approach, we defined a set of diverse, small molecules that interfere with auxin-induced Ca2+ entry. Based on annotated biological activities of the hit molecules, we found that auxin-induced Ca2+ signaling is, among others, highly sensitive to disruption of membrane proton gradients and the mammalian Ca2+ channel inhibitor bepridil. Whereas protonophores nonselectively inhibited auxin-induced and osmotic stress-induced Ca2+ signals, bepridil specifically inhibited auxin-induced Ca2+ We found evidence that bepridil severely alters vacuolar morphology and antagonized auxin-induced vacuolar remodeling. Further exploration of this plant-tailored collection of inhibitors will lead to a better understanding of auxin-induced Ca2+ entry and its relevance for auxin responses.

Genetic buffering of cyclic AMP in Arabidopsis thaliana compromises the plant immune response triggered by an avirulent strain of Pseudomonas syringae pv. tomato.

Cyclic AMP plays important roles in different physiological processes, including plant defence responses. However, as little information is known on plant enzymes responsible for cAMP production/degradation, studies of cAMP functions have relied, to date, on non-specific pharmacological approaches. We therefore developed a more reliable approach, producing transgenic Arabidopsis thaliana lines overexpressing the 'cAMP-sponge' (cAS), a genetic tool that specifically buffers cAMP levels. In response to an avirulent strain of Pseudomonas syringae pv. tomato (PstAvrB), cAS plants showed a higher bacterial growth and a reduced hypersensitive cell death in comparison with wild-type (WT) plants. The low cAMP availability after pathogen infection delayed cytosolic calcium elevation, as well as hydrogen peroxide increase and induction of redox systems. The proteomic analysis, performed 24 h post-infection, indicated that a core of 49 proteins was modulated in both genotypes, while 16 and 42 proteins were uniquely modulated in WT and cAS lines, respectively. The involvement of these proteins in the impairment of defence response in cAS plants is discussed in this paper. Moreover, in silico analysis revealed that the promoter regions of the genes coding for proteins uniquely accumulating in WT plants shared the CGCG motif, a target of the calcium-calmodulin-binding transcription factor AtSR1 (Arabidopsis thaliana signal responsive1). Therefore, following pathogen perception, the low free cAMP content, altering timing and levels of defence signals, and likely acting in part through the mis-regulation of AtSR1 activity, affected the speed and strength of the immune response.

Redox Homeostasis in Photosynthetic Organisms: Novel and Established Thiol-Based Molecular Mechanisms.

Significance: Redox homeostasis consists of an intricate network of reactions in which reactive molecular species, redox modifications, and redox proteins act in concert to allow both physiological responses and adaptation to stress conditions. Recent Advances: This review highlights established and novel thiol-based regulatory pathways underlying the functional facets and significance of redox biology in photosynthetic organisms. In the last decades, the field of redox regulation has largely expanded and this work is aimed at giving the right credit to the importance of thiol-based regulatory and signaling mechanisms in plants. Critical Issues: This cannot be all-encompassing, but is intended to provide a comprehensive overview on the structural/molecular mechanisms governing the most relevant thiol switching modifications with emphasis on the large genetic and functional diversity of redox controllers (i.e., redoxins). We also summarize the different proteomic-based approaches aimed at investigating the dynamics of redox modifications and the recent evidence that extends the possibility to monitor the cellular redox state in vivo. The physiological relevance of redox transitions is discussed based on reverse genetic studies confirming the importance of redox homeostasis in plant growth, development, and stress responses. Future Directions: In conclusion, we can firmly assume that redox biology has acquired an established significance that virtually infiltrates all aspects of plant physiology.

The fluorescent protein sensor roGFP2-Orp1 monitors in vivo H2 O2 and thiol redox integration and elucidates intracellular H2 O2 dynamics during elicitor-induced oxidative burst in Arabidopsis.

Hydrogen peroxide (H2 O2 ) is ubiquitous in cells and at the centre of developmental programmes and environmental responses. Its chemistry in cells makes H2 O2 notoriously hard to detect dynamically, specifically and at high resolution. Genetically encoded sensors overcome persistent shortcomings, but pH sensitivity, silencing of expression and a limited concept of sensor behaviour in vivo have hampered any meaningful H2 O2 sensing in living plants. We established H2 O2 monitoring in the cytosol and the mitochondria of Arabidopsis with the fusion protein roGFP2-Orp1 using confocal microscopy and multiwell fluorimetry. We confirmed sensor oxidation by H2 O2 , show insensitivity to physiological pH changes, and demonstrated that glutathione dominates sensor reduction in vivo. We showed the responsiveness of the sensor to exogenous H2 O2 , pharmacologically-induced H2 O2 release, and genetic interference with the antioxidant machinery in living Arabidopsis tissues. Monitoring intracellular H2 O2 dynamics in response to elicitor exposure reveals the late and prolonged impact of the oxidative burst in the cytosol that is modified in redox mutants. We provided a well defined toolkit for H2 O2 monitoring in planta and showed that intracellular H2 O2 measurements only carry meaning in the context of the endogenous thiol redox systems. This opens new possibilities to dissect plant H2 O2 dynamics and redox regulation, including intracellular NADPH oxidase-mediated ROS signalling.

Surgical management of a giant right atrial myxoma.

Cardiac tumours represent around 0.2% of tumours overall, and primary cardiac tumours are even more uncommon. We report the case of a 72-year-old female with a 7 cm × 4 cm right atrial mass which was prolapsing through the tricuspid valve. The mass was resected and histological analysis confirmed a myxoma. This report describes a rare finding of a giant right atrial mxyoma and subsequent surgical management.

Coloanal intussusception in adults due to lipoma / Intussuscepção colo-anal decorrente de lipoma em adulto

ABSTRACT Adult intussusception is a rare condition. But coloanal intussusception is an exception. Malignant lesions are the most common cause of colonic intussusception, and in this aspect, differ from childhood intussusception. We present a case wherein the patient had a lipoma of the sigmoid colon that caused an immense prolapse through the anus. Very few cases of coloanal intussusception are reported in adults, and we discuss the diagnostic tools and the management of this rare surgical entity.

RESUMO A intussuscepção no adulto é uma entidade rara. Mas a intussuscepção colo-anal é uma exceção. Lesões malignas são a causa mais comum de intussuscepção colônica e, neste aspecto, difere da intussuscepção infantil. Apresentamos um caso de lipoma do cólon sigmoide que causou um prolapso imenso através do ânus. Muito poucos casos de intussuscepção colo-anal foram relatados em adultos e discutimos as ferramentas diagnósticas e o tratamento dessa entidade cirúrgica rara.

Mutual Influence of ROS, pH, and CLIC1 Membrane Protein in the Regulation of G1-S Phase Progression in Human Glioblastoma Stem Cells.

Glioblastoma (GB) is the most lethal, aggressive, and diffuse brain tumor. The main challenge for successful treatment is targeting the cancer stem cell (CSC) subpopulation responsible for tumor origin, progression, and recurrence. Chloride Intracellular Channel 1 (CLIC1), highly expressed in CSCs, is constitutively present in the plasma membrane where it is associated with chloride ion permeability. In vitro, CLIC1 inhibition leads to a significant arrest of GB CSCs in G1 phase of the cell cycle. Furthermore, CLIC1 knockdown impairs tumor growth in vivo Here, we demonstrate that CLIC1 membrane localization and function is specific for GB CSCs. Mesenchymal stem cells (MSC) do not show CLIC1-associated chloride permeability, and inhibition of CLIC1 protein function has no influence on MSC cell-cycle progression. Investigation of the basic functions of GB CSCs reveals a constitutive state of oxidative stress and cytoplasmic alkalinization compared with MSCs. Both intracellular oxidation and cytoplasmic pH changes have been reported to affect CLIC1 membrane functional expression. We now report that in CSCs these three elements are temporally linked during CSC G1-S transition. Impeding CLIC1-mediated chloride current prevents both intracellular ROS accumulation and pH changes. CLIC1 membrane functional impairment results in GB CSCs resetting from an allostatic tumorigenic condition to a homeostatic steady state. In contrast, inhibiting NADPH oxidase and NHE1 proton pump results in cell death of both GB CSCs and MSCs. Our results show that CLIC1 membrane protein is crucial and specific for GB CSC proliferation, and is a promising pharmacologic target for successful brain tumor therapies. Mol Cancer Ther; 17(11); 2451-61. ©2018 AACR.

In Vivo Analysis of Calcium Levels and Glutathione Redox Status in Arabidopsis Epidermal Leaf Cells Infected with the Hypersensitive Response-Inducing Bacteria Pseudomonas syringae pv. tomato AvrB (PstAvrB).

Plants react to the attack of pathogen microorganisms by mounting appropriate and efficient downstream defense responses often involving a form of localized cell death called hypersensitive response (HR).Here we describe an innovative and noninvasive protocol based on in vivo bioimaging technique coupled with utilization of genetically encoded fluorescent sensors that allows to monitor and analyze intracellular calcium (Ca2+) dynamics and changes of the glutathione redox status taking place in plant organs during plant interaction with the HR-inducing bacteria Pseudomonas syringae (PstAvrB).

Liability for providing a prognosis in surgical practice.

The common law's development of the doctrine of informed consent has progressively imposed broader obligations on surgeons to provide patients with information about the surgical and alternative treatment choices available. Prognosis is critical because the patient cannot provide informed consent without information about the likely evolution of the physiological or pathological processes involved in the surgery under consideration. But does the duty of care that a surgeon owes a patient require a precise prognosis to be given in every case? A recent decision of the Court of Appeal considers that question.

ATP sensing in living plant cells reveals tissue gradients and stress dynamics of energy physiology.

Growth and development of plants is ultimately driven by light energy captured through photosynthesis. ATP acts as universal cellular energy cofactor fuelling all life processes, including gene expression, metabolism, and transport. Despite a mechanistic understanding of ATP biochemistry, ATP dynamics in the living plant have been largely elusive. Here, we establish MgATP2- measurement in living plants using the fluorescent protein biosensor ATeam1.03-nD/nA. We generate Arabidopsis sensor lines and investigate the sensor in vitro under conditions appropriate for the plant cytosol. We establish an assay for ATP fluxes in isolated mitochondria, and demonstrate that the sensor responds rapidly and reliably to MgATP2- changes in planta. A MgATP2- map of the Arabidopsis seedling highlights different MgATP2- concentrations between tissues and within individual cell types, such as root hairs. Progression of hypoxia reveals substantial plasticity of ATP homeostasis in seedlings, demonstrating that ATP dynamics can be monitored in the living plant.

Ca2+-dependent phosphoregulation of the plasma membrane Ca2+-ATPase ACA8 modulates stimulus-induced calcium signatures.

Ca2+ signals are transient, hence, upon a stimulus-induced increase in cytosolic Ca2+ concentration, cells have to re-establish resting Ca2+ levels. Ca2+ extrusion is operated by a wealth of transporters, such as Ca2+ pumps and Ca2+/H+ antiporters, which often require a rise in Ca2+ concentration to be activated. Here, we report a regulatory fine-tuning mechanism of the Arabidopsis thaliana plasma membrane-localized Ca2+-ATPase isoform ACA8 that is mediated by calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) complexes. We show that two CIPKs (CIPK9 and CIPK14) are able to interact with ACA8 in vivo and phosphorylate it in vitro. Transient co-overexpression of ACA8 with CIPK9 and the plasma membrane Ca2+ sensor CBL1 in tobacco leaf cells influences nuclear Ca2+ dynamics, specifically reducing the height of the second peak of the wound-induced Ca2+ transient. Stimulus-induced Ca2+ transients in mature leaves and seedlings of an aca8 T-DNA insertion line exhibit altered dynamics when compared with the wild type. Altogether our results identify ACA8 as a prominent in vivo regulator of cellular Ca2+ dynamics and reveal the existence of a Ca2+-dependent CBL-CIPK-mediated regulatory feedback mechanism, which crucially functions in the termination of Ca2+ signals.

Effects of Neural Stem Cell and Olfactory Ensheathing Cell Co-transplants on Tissue Remodelling After Transient Focal Cerebral Ischemia in the Adult Rat.

Effective transplant-mediated repair of ischemic brain lesions entails extensive tissue remodeling, especially in the ischemic core. Neural stem cells (NSCs) are promising reparative candidates for stroke induced lesions, however, their survival and integration with the host-tissue post-transplantation is poor. In this study, we address this challenge by testing whether co-grafting of NSCs with olfactory ensheathing cells (OECs), a special type of glia with proven neuroprotective, immunomodulatory, and angiogenic effects, can promote graft survival and host tissue remodelling. Transient focal cerebral ischemia was induced in adult rats by a 60-min middle cerebral artery occlusion (MCAo) followed by reperfusion. Ischemic lesions were verified by neurological testing and magnetic resonance imaging. Transplantation into the globus pallidus of NSCs alone or in combination with OECs was performed at two weeks post-MCAo, followed by histological analyses at three weeks post-transplantation. We found evidence of extensive vascular remodelling in the ischemic core as well as evidence of NSC motility away from the graft and into the infarct border in severely lesioned animals co-grafted with OECs. These findings support a possible role of OECs as part of an in situ tissue engineering paradigm for transplant mediated repair of ischemic brain lesions.