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Sample records for cell compartmentation

  1. Regulatory T-cell compartmentalization and trafficking

    OpenAIRE

    Wei, Shuang; Kryczek, Ilona; Zou, Weiping

    2006-01-01

    CD4+CD25+FOXP3+ regulatory T cells (CD4+ Treg cells) are thought to differentiate in the thymus and immigrate from the thymus to the periphery. Treg cells can regulate both acquired and innate immunity through multiple modes of suppression. The cross-talk between Treg cells and targeted cells, such as antigen-presenting cells (APCs) and T cells, is crucial for ensuring suppression by Treg cells in the appropriate microenvironment. Emerging evidence suggests that Treg compartmentalization and ...

  2. Human memory T cells: generation, compartmentalization and homeostasis

    Science.gov (United States)

    Farber, Donna L.; Yudanin, Naomi A.; Restifo, Nicholas P.

    2014-01-01

    Memory T cells comprise the most abundant lymphocyte population in the body for the majority of one’s lifetime; however, our understanding of memory T cell generation, function and maintenance mainly derives from mouse studies, which cannot recapitulate the decades-long exposure to multiple pathogens that occurs in humans. Here, we review studies focused on human memory T cells that reveal key properties including subset heterogeneity and diverse tissue residence in multiple mucosal and lymphoid tissue sites. We also discuss how the function and adaptability of human memory T cells depend on spatial and temporal compartmentalization. PMID:24336101

  3. Compartmentation and equilibration of abscisic acid in isolated Xanthium cells

    Energy Technology Data Exchange (ETDEWEB)

    Bray, E.A.; Zeevaart, J.A.D.

    1986-01-01

    The compartmentation of endogenous abscisic acid (ABA), applied (+/-)-(/sup 3/H)ABA, and (+/-)-trans-ABA was measured in isolated mesophyll cells of the Chicago strain of Xanthium strumarium L. The release of ABA to the medium in the presence or absence of DMSO was used to determine the equilibration of ABA in the cells. It was found that a greater percentage of the (+/-)-(/sup 3/H)ABA and the (+/-)-trans-ABA was released into the medium than of the endogenous ABA, indicating that applied ABA did not equilibrate with the endogenous material. Therefore, in further investigations only the compartmentation of endogenous ABA was studied. Endogenous ABA was released from Xanthium cells according to the pH gradients among the various cellular compartments. Thus, darkness, high external pH, KNO/sub 2/, and drought-stress all increased the efflux of ABA from the cells. Efflux of ABA from the cells in the presence of 0.6 M mannitol occurred within 30 seconds, but only 8% of the endogenous material was released during the 20 minute treatment.

  4. The compartmentation of phosphorylated thiamine derivatives in cultured neuroblastoma cells.

    Science.gov (United States)

    Bettendorff, L

    1994-05-26

    Thiamine transport in cultured neuroblastoma cells is mediated by a high-affinity carrier (KM = 40 nM). In contrast, the uptake of the more hydrophobic sulbutiamine (isobutyrylthiamine disulfide) is unsaturable and its initial transport rate is 20-times faster than for thiamine. In the cytoplasm, sulbutiamine is rapidly hydrolyzed and reduced to free thiamine, the overall process resulting in a rapid and concentrative thiamine accumulation. Incorporation of radioactivity from [14C]thiamine or [14C]sulbutiamine into intracellular thiamine diphosphate is slow in both cases. Despite the fact that the diphosphate is probably the direct precursor for both thiamine monophosphate and triphosphate, the specific radioactivity increased much faster for the latter two compounds than for thiamine diphosphate. This suggests the existence of two pools of thiamine diphosphate, the larger one having a very slow turnover (about 17 h); a much smaller, rapidly turning over pool would be the precursor of thiamine mono- and triphosphate. The turnover time for thiamine triphosphate could be estimated to be 1-2 h. When preloading the cells with [14C]sulbutiamine was followed by a chase with the same concentration of the unlabeled compound, the specific radioactivities of thiamine and thiamine monophosphate decreased exponentially as expected, but labeling of the diphosphate continued to increase slowly. Specific radioactivity of thiamine triphosphate increased first, but after 30 min it began to slowly decrease. These results show for the first time the existence of distinct thiamine diphosphate pools in the same homogeneous cell population. They also suggest a complex compartmentation of thiamine metabolism. PMID:8186267

  5. An actomyosin-based barrier inhibits cell mixing at compartmental boundaries in Drosophila embryos.

    Science.gov (United States)

    Monier, Bruno; Pélissier-Monier, Anne; Brand, Andrea H; Sanson, Bénédicte

    2010-01-01

    Partitioning tissues into compartments that do not intermix is essential for the correct morphogenesis of animal embryos and organs. Several hypotheses have been proposed to explain compartmental cell sorting, mainly differential adhesion, but also regulation of the cytoskeleton or of cell proliferation. Nevertheless, the molecular and cellular mechanisms that keep cells apart at boundaries remain unclear. Here we demonstrate, in early Drosophila melanogaster embryos, that actomyosin-based barriers stop cells from invading neighbouring compartments. Our analysis shows that cells can transiently invade neighbouring compartments, especially when they divide, but are then pushed back into their compartment of origin. Actomyosin cytoskeletal components are enriched at compartmental boundaries, forming cable-like structures when the epidermis is mitotically active. When MyoII (non-muscle myosin II) function is inhibited, including locally at the cable by chromophore-assisted laser inactivation (CALI), in live embryos, dividing cells are no longer pushed back, leading to compartmental cell mixing. We propose that local regulation of actomyosin contractibility, rather than differential adhesion, is the primary mechanism sorting cells at compartmental boundaries. PMID:19966783

  6. Phylum Verrucomicrobia representatives share a compartmentalized cell plan with members of bacterial phylum Planctomycetes

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    Romeo Tony

    2009-01-01

    Full Text Available Abstract Background The phylum Verrucomicrobia is a divergent phylum within domain Bacteria including members of the microbial communities of soil and fresh and marine waters; recently extremely acidophilic members from hot springs have been found to oxidize methane. At least one genus, Prosthecobacter, includes species with genes homologous to those encoding eukaryotic tubulins. A significant superphylum relationship of Verrucomicrobia with members of phylum Planctomycetes possessing a unique compartmentalized cell plan, and members of the phylum Chlamydiae including human pathogens with a complex intracellular life cycle, has been proposed. Based on the postulated superphylum relationship, we hypothesized that members of the two separate phyla Planctomycetes and Verrucomicrobia might share a similar ultrastructure plan differing from classical prokaryote organization. Results The ultrastructure of cells of four members of phylum Verrucomicrobia – Verrucomicrobium spinosum, Prosthecobacter dejongeii, Chthoniobacter flavus, and strain Ellin514 – was examined using electron microscopy incorporating high-pressure freezing and cryosubstitution. These four members of phylum Verrucomicrobia, representing 3 class-level subdivisions within the phylum, were found to possess a compartmentalized cell plan analogous to that found in phylum Planctomycetes. Like all planctomycetes investigated, they possess a major pirellulosome compartment containing a condensed nucleoid and ribosomes surrounded by an intracytoplasmic membrane (ICM, as well as a ribosome-free paryphoplasm compartment between the ICM and cytoplasmic membrane. Conclusion A unique compartmentalized cell plan so far found among Domain Bacteria only within phylum Planctomycetes, and challenging our concept of prokaryote cell plans, has now been found in a second phylum of the Domain Bacteria, in members of phylum Verrucomicrobia. The planctomycete cell plan thus occurs in at least two

  7. Human memory T cells: generation, compartmentalization and homeostasis

    OpenAIRE

    Farber, Donna L.; Yudanin, Naomi A.; Restifo, Nicholas P

    2013-01-01

    Memory T cells comprise the most abundant lymphocyte population in the body for the majority of one’s lifetime; however, our understanding of memory T cell generation, function and maintenance mainly derives from mouse studies, which cannot recapitulate the decades-long exposure to multiple pathogens that occurs in humans. Here, we review studies focused on human memory T cells that reveal key properties including subset heterogeneity and diverse tissue residence in multiple mucosal and lymph...

  8. Folded genome as a platform for the functional compartmentalization of the eukaryotic cell nucleus

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    Ioudinkova E. S.

    2014-03-01

    Full Text Available In a number of recent studies a tight interconnection between the spatial organization of the eukaryotic genome and its functioning has been demonstrated. Moreover, it is becoming evident that the folded DNA by itself consti- tutes an important, if not the key, factor supporting the internal nuclear organization. In this review, we will discuss the current state of chromatin research with the special attention focused on chromosome territories, chromatin folding and dynamics, chromatin domains, transcription and replication factories. Based on this analysis we will show how interphase chromosomes define the assembly of different nuclear compartments and underlie the spatial compartmentalization of the cell nucleus.

  9. The cell cycle of the planctomycete Gemmata obscuriglobus with respect to cell compartmentalization

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    Fuerst John A

    2009-01-01

    Full Text Available Abstract Background Gemmata obscuriglobus is a distinctive member of the divergent phylum Planctomycetes, all known members of which are peptidoglycan-less bacteria with a shared compartmentalized cell structure and divide by a budding process. G. obscuriglobus in addition shares the unique feature that its nucleoid DNA is surrounded by an envelope consisting of two membranes forming an analogous structure to the membrane-bounded nucleoid of eukaryotes and therefore G. obscuriglobus forms a special model for cell biology. Draft genome data for G. obscuriglobus as well as complete genome sequences available so far for other planctomycetes indicate that the key bacterial cell division protein FtsZ is not present in these planctomycetes, so the cell division process in planctomycetes is of special comparative interest. The membrane-bounded nature of the nucleoid in G. obscuriglobus also suggests that special mechanisms for the distribution of this nuclear body to the bud and for distribution of chromosomal DNA might exist during division. It was therefore of interest to examine the cell division cycle in G. obscuriglobus and the process of nucleoid distribution and nuclear body formation during division in this planctomycete bacterium via light and electron microscopy. Results Using phase contrast and fluorescence light microscopy, and transmission electron microscopy, the cell division cycle of G. obscuriglobus was determined. During the budding process, the bud was formed and developed in size from one point of the mother cell perimeter until separation. The matured daughter cell acted as a new mother cell and started its own budding cycle while the mother cell can itself initiate budding repeatedly. Fluorescence microscopy of DAPI-stained cells of G. obscuriglobus suggested that translocation of the nucleoid and formation of the bud did not occur at the same time. Confocal laser scanning light microscopy applied to cells stained for membranes as

  10. The role of the bi-compartmental stem cell niche in delaying cancer

    Science.gov (United States)

    Shahriyari, Leili; Komarova, Natalia L.

    2015-10-01

    In recent years, by using modern imaging techniques, scientists have found evidence of collaboration between different types of stem cells (SCs), and proposed a bi-compartmental organization of the SC niche. Here we create a class of stochastic models to simulate the dynamics of such a heterogeneous SC niche. We consider two SC groups: the border compartment, S1, is in direct contact with transit-amplifying (TA) cells, and the central compartment, S2, is hierarchically upstream from S1. The S1 SCs differentiate or divide asymmetrically when the tissue needs TA cells. Both groups proliferate when the tissue requires SCs (thus maintaining homeostasis). There is an influx of S2 cells into the border compartment, either by migration, or by proliferation. We examine this model in the context of double-hit mutant generation, which is a rate-limiting step in the development of many cancers. We discover that this type of a cooperative pattern in the stem niche with two compartments leads to a significantly smaller rate of double-hit mutant production compared with a homogeneous, one-compartmental SC niche. Furthermore, the minimum probability of double-hit mutant generation corresponds to purely symmetric division of SCs, consistent with the literature. Finally, the optimal architecture (which minimizes the rate of double-hit mutant production) requires a large proliferation rate of S1 cells along with a small, but non-zero, proliferation rate of S2 cells. This result is remarkably similar to the niche structure described recently by several authors, where one of the two SC compartments was found more actively engaged in tissue homeostasis and turnover, while the other was characterized by higher levels of quiescence (but contributed strongly to injury recovery). Both numerical and analytical results are presented.

  11. Subcellular compartmentalization in protoplasts from Artemisia annua cell cultures: engineering attempts using a modified SNARE protein.

    Science.gov (United States)

    Di Sansebastiano, Gian Pietro; Rizzello, Francesca; Durante, Miriana; Caretto, Sofia; Nisi, Rossella; De Paolis, Angelo; Faraco, Marianna; Montefusco, Anna; Piro, Gabriella; Mita, Giovanni

    2015-05-20

    Plants are ideal bioreactors for the production of macromolecules but transport mechanisms are not fully understood and cannot be easily manipulated. Several attempts to overproduce recombinant proteins or secondary metabolites failed. Because of an independent regulation of the storage compartment, the product may be rapidly degraded or cause self-intoxication. The case of the anti-malarial compound artemisinin produced by Artemisia annua plants is emblematic. The accumulation of artemisinin naturally occurs in the apoplast of glandular trichomes probably involving autophagy and unconventional secretion thus its production by undifferentiated tissues such as cell suspension cultures can be challenging. Here we characterize the subcellular compartmentalization of several known fluorescent markers in protoplasts derived from Artemisia suspension cultures and explore the possibility to modify compartmentalization using a modified SNARE protein as molecular tool to be used in future biotechnological applications. We focused on the observation of the vacuolar organization in vivo and the truncated form of AtSYP51, 51H3, was used to induce a compartment generated by the contribution of membrane from endocytosis and from endoplasmic reticulum to vacuole trafficking. The artificial compartment crossing exocytosis and endocytosis may trap artemisinin stabilizing it until extraction; indeed, it is able to increase total enzymatic activity of a vacuolar marker (RGUSChi), probably increasing its stability. Exploring the 51H3-induced compartment we gained new insights on the function of the SNARE SYP51, recently shown to be an interfering-SNARE, and new hints to engineer eukaryote endomembranes for future biotechnological applications.

  12. Information Processing in Single Cells and Small Networks: Insights from Compartmental Models

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    Poirazi, Panayiota

    2009-03-01

    The goal of this paper is to present a set of predictions generated by detailed compartmental models regarding the ways in which information may be processed, encoded and propagated by single cells and neural assemblies. Towards this goal, I will review a number of modelling studies from our lab that investigate how single pyramidal neurons and small neural networks in different brain regions process incoming signals that are associated with learning and memory. I will first discuss the computational capabilities of individual pyramidal neurons in the hippocampus [1-3] and how these properties may allow a single cell to discriminate between different memories [4]. I will then present biophysical models of prefrontal layer V neurons and small networks that exhibit sustained activity under realistic synaptic stimulation and discuss their potential role in working memory [5].

  13. Local Microenvironment Controls the Compartmentalization of NK Cell Responses during Systemic Inflammation in Mice.

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    Rasid, Orhan; Ciulean, Ioana Sonya; Fitting, Catherine; Doyen, Noelle; Cavaillon, Jean-Marc

    2016-09-15

    Systemic inflammatory response syndrome is a whole-body reaction to a triggering insult that often results in life-threatening illness. Contributing to the development of this inflammatory cascade are numerous cellular partners, among which NK cells were shown to play a key role. Accumulating evidence points to organ-specific properties of systemic inflammation and NK cells. However, little is known about compartment-specific activation of NK cells during systemic inflammatory response syndrome or the relative contribution of NK cell-intrinsic properties and microenvironmental cues. In this study, we undertook a sequential characterization of NK responses in the spleen, lungs, bone marrow, peritoneum, and blood using a mouse model of endotoxemia. We report that, despite similar systemic dynamics of NK cell responses, expression of activation markers (CD69 and CD25) and effector molecules (IFN-γ, granzyme B, and IL-10) display organ-specific thresholds of maximum activation. Using adoptive transfers of spleen and lung NK cells, we found that these cells have the capacity to quickly adapt to a new environment and adjust their response levels to that of resident NK cells. This functional adaptation occurs without significant alterations in phenotype and independently of subpopulation-specific trafficking. Thus, using a dynamic in vivo-transfer system, to our knowledge our study is the first to report the compartmentalization of NK cells responses during systemic inflammation and to show that NK cell-intrinsic properties and microenvironmental cues are involved in this process, in a sequential manner. PMID:27521338

  14. Lipid droplet-associated proteins (LDAPs) are required for the dynamic regulation of neutral lipid compartmentation in plant cells

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    Eukaryotic cells compartmentalize neutral lipids into organelles called lipid droplets (LDs), and while much is known about the role of LDs in storing triacylglycerols (TAGs) in seeds, their biogenesis and function in non-seed tissues is poorly understood. Recently, we identified a class of plant-sp...

  15. Hepatic compartmentalization of exhausted and regulatory cells in HIV/HCV-coinfected patients.

    Science.gov (United States)

    Barrett, L; Trehanpati, N; Poonia, S; Daigh, L; Sarin, S Kumar; Masur, H; Kottilil, S

    2015-03-01

    Accelerated intrahepatic hepatitis C virus (HCV) pathogenesis is likely the result of dysregulation within both the innate and adaptive immune compartments, but the exact contribution of peripheral blood and liver lymphocyte subsets remains unclear. Prolonged activation and expansion of immunoregulatory cells have been thought to play a role. We determined immune cell subset frequency in contemporaneous liver and peripheral blood samples from chronic HCV-infected and HIV/HCV-coinfected individuals. Peripheral blood mononuclear cells (PBMC) and biopsy-derived liver-infiltrating lymphocytes from 26 HIV/HCV-coinfected, 10 chronic HCV-infected and 10 HIV-infected individuals were assessed for various subsets of T and B lymphocytes, dendritic cell, natural killer (NK) cell and NK T-cell frequency by flow cytometry. CD8(+) T cells expressing the exhaustion marker PD-1 were increased in HCV-infected individuals compared with uninfected individuals (P = 0.02), and HIV coinfection enhanced this effect (P = 0.005). In the liver, regulatory CD4(+) CD25(+) Foxp3(+) T cells, as well as CD4(+) CD25(+) PD1(+) T cells, were more frequent in HIV/HCV-coinfected than in HCV-monoinfected samples (P HIV infection (P ≤ 0.005 for all). Low CD8(+) expression was observed only in PD-1(+) CD8(+) T cells from HCV-infected individuals and healthy controls (P = 0.002) and was associated with enhanced expansion of exhausted CD8(+) T cells when exposed in vitro to PHA or CMV peptides. In conclusion, in HIV/HCV coinfection, ongoing HCV replication is associated with increased regulatory and exhausted T cells in the periphery and liver that may impact control of HCV. Simultaneous characterization of liver and peripheral blood highlights the disproportionate intrahepatic compartmentalization of immunoregulatory T cells, which may contribute to establishment of chronicity and hepatic fibrogenesis in HIV coinfection.

  16. Bystander effects and compartmental stress response to X-ray irradiation in L929 cells.

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    Temelie, Mihaela; Stroe, Daniela; Petcu, Ileana; Mustaciosu, Cosmin; Moisoi, Nicoleta; Savu, Diana

    2016-08-01

    Bystander effects are indirect consequences of radiation and many other stress factors. They occur in cells that are not directly exposed to these factors, but receive signals from affected cells either by gap junctions or by molecules released in the medium. Characterizing these effects and deciphering the underlying mechanisms involved in radiation-induced bystander effects are relevant for cancer radiotherapy and radioprotection. At doses of X-ray radiation 0.5 and 1 Gy, we detected bystander effects as increased numbers of micronuclei shortly after the treatment, through medium transfer and by co-cultures. Interestingly, bystander cells did not exhibit long-term adverse changes in viability. Evaluation of several compartmental stress markers (CHOP, BiP, mtHsp60, cytHsp70) by qRT-PCR did not reveal expression changes at transcriptional level. We investigated the involvement of ROS and NO in this process by addition of specific scavengers of these molecules, DMSO or c-PTIO in the transferred medium. This approach proved that ROS but not NO is involved in the induction of lesions in the acceptor cells. These results indicate that L929 cells are susceptible to stress effects of radiation-induced bystander signaling. PMID:27025606

  17. Modulation of cytokine release by differentiated CACO-2 cells in a compartmentalized coculture model with mononuclear leucocytes and nonpathogenic bacteria

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Haller, D.; Brinz, S.;

    2004-01-01

    cells when leucocytes were stimulated directly with bacteria. This suppression was not paralleled by changes in the production of IL-10, IL-6 and transforming growth factor (TGF)-beta. When the bacteria were applied apically to the CACO-2 cell layer, the production of TNF-alpha, IL-12, IL-1beta, IL-8......To further investigate the interaction between human mononuclear leucocytes [peripheral blood mononuclear cells (PBMC)] and enterocytes, the effect of a confluent layer of differentiated CACO-2 cells on cytokine kinetics during challenge with bacteria in a compartmentalized coculture model...... analysis revealed that IL-8 gene expression was equally induced in both CACO-2 and PBMC after apical stimulation with bacteria. Of note, bacteria-stimulated CACO-2 cells produced little or no cytokines in the absence of leucocytes, supporting the concept of leucocyte-epithelial cell cross...

  18. Early-life compartmentalization of human T cell differentiation and regulatory function in mucosal and lymphoid tissues.

    Science.gov (United States)

    Thome, Joseph J C; Bickham, Kara L; Ohmura, Yoshiaki; Kubota, Masaru; Matsuoka, Nobuhide; Gordon, Claire; Granot, Tomer; Griesemer, Adam; Lerner, Harvey; Kato, Tomoaki; Farber, Donna L

    2016-01-01

    It is unclear how the immune response in early life becomes appropriately stimulated to provide protection while also avoiding excessive activation as a result of diverse new antigens. T cells are integral to adaptive immunity; mouse studies indicate that tissue localization of T cell subsets is important for both protective immunity and immunoregulation. In humans, however, the early development and function of T cells in tissues remain unexplored. We present here an analysis of lymphoid and mucosal tissue T cells derived from pediatric organ donors in the first two years of life, as compared to adult organ donors, revealing early compartmentalization of T cell differentiation and regulation. Whereas adult tissues contain a predominance of memory T cells, in pediatric blood and tissues the main subset consists of naive recent thymic emigrants, with effector memory T cells (T(EM)) found only in the lungs and small intestine. Additionally, regulatory T (T(reg)) cells comprise a high proportion (30-40%) of CD4(+) T cells in pediatric tissues but are present at much lower frequencies (1-10%) in adult tissues. Pediatric tissue T(reg) cells suppress endogenous T cell activation, and early T cell functionality is confined to the mucosal sites that have the lowest T(reg):T(EM) cell ratios, which suggests control in situ of immune responses in early life.

  19. Cellular compartmentalization of secondary metabolism

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    H. Corby eKistler

    2015-02-01

    Full Text Available Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g. amino acids, acetyl CoA, NADPH, enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

  20. The Role of Cell Compartmentalization and Cell Differentiation in Cyanobacterial Excavation of Miineral Carbonates

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    Garcia-Pichel, F.; Guida, B. S.; Couradeau, E.

    2015-12-01

    The bioerosion of coastal limestones and biogenic carbonates by boring filamentous or pseudo-filamentous cyanobacteria is not only a geomicrobial phenomenon of global proportions, but also plays an important role in the demise of coral reefs, and affects significantly human enterprises like bivalve fisheries. In spite of its importance, the mechanism by which cyanobacteria excavate carbonates constitutes an apparent paradox, in that their metabolism will tend to precipitate carbonates, not dissolved them. We have previously advanced, and obtained evidence for, a mechanism of excavation that relies on the uptake of Ca2+ by cells at the boring front, its trans-cellular transport along the filaments, and its eventual active excretion at the solid/liquid interface. It was postulated that the mechanism involved the strategically organized deployment of Ca2+ transport enzymes like P-type Ca2+ ATPases and Ca2+ channels. Here we present evidence that confirms this basic mechanism, but also reveals that it is based on an unexpected level of cellular complexity. The model organism Mastigocoleus testarum BC008, transports Ca2+ from the mineral to the external medium using a repetitive, polar arrangement of Ca2+ ATPases, localized preferentially on one cellular pole, in a ring conformation on the cell membrane adjacent to the trans-cellular septum, pumping Ca2+ locally towards the periplasmic space, from which it passively enters the next cell. This strain also develops specialized groups of cells, which we named calcicytes, often but not exclusively located at the ends of filaments, that accumulate large concentrations of Ca2+, some 40-fold higher than typical in microbes, and seem to act as sinks or capacitors in the trans-cellular Ca2+ transport. Calcicytes are also characterized by a lack of photosynthetic pigments, and a very high intracellular pH. These cellular adaptations can also be found in evolutionary distant euendoliths such as the pseudofilamentous Hyella sp.

  1. Communication Between the Cell Membrane and the Nucleus: Role of Protein Compartmentalization

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    Lelievre, Sophie A; Bissell, Mina J

    1998-10-21

    Understanding how the information is conveyed from outside to inside the cell is a critical challenge for all biologists involved in signal transduction. The flow of information initiated by cell-cell and cell-extracellular matrix contacts is mediated by the formation of adhesion complexes involving multiple proteins. Inside adhesion complexes, connective membrane skeleton (CMS) proteins are signal transducers that bind to adhesion molecules, organize the cytoskeleton, and initiate biochemical cascades. Adhesion complex-mediated signal transduction ultimately directs the formation of supramolecular structures in the cell nucleus, as illustrated by the establishment of multi complexes of DNA-bound transcription factors, and the redistribution of nuclear structural proteins to form nuclear subdomains. Recently, several CMS proteins have been observed to travel to the cell nucleus, suggesting a distinctive role for these proteins in signal transduction. This review focuses on the nuclear translocation of structural signal transducers of the membrane skeleton and also extends our analysis to possible translocation of resident nuclear proteins to the membrane skeleton. This leads us to envision the communication between spatially distant cellular compartments (i.e., membrane skeleton and cell nucleus) as a bidirectional flow of information (a dynamic reciprocity) based on subtle multilevel structural and biochemical equilibria. At one level, it is mediated by the interaction between structural signal transducers and their binding partners, at another level it may be mediated by the balance and integration of signal transducers in different cellular compartments.

  2. Compartmentalization of GABA synthesis by GAD67 differs between pancreatic beta cells and neurons

    DEFF Research Database (Denmark)

    Kanaani, Jamil; Cianciaruso, Chiara; Phelps, Edward A;

    2015-01-01

    The inhibitory neurotransmitter GABA is synthesized by the enzyme glutamic acid decarboxylase (GAD) in neurons and in pancreatic β-cells in islets of Langerhans where it functions as a paracrine and autocrine signaling molecule regulating the function of islet endocrine cells. The localization...... of the two non-allelic isoforms GAD65 and GAD67 to vesicular membranes is important for rapid delivery and accumulation of GABA for regulated secretion. While the membrane anchoring and trafficking of GAD65 are mediated by intrinsic hydrophobic modifications, GAD67 remains hydrophilic, and yet is targeted...... accumulation of newly synthesized GABA for regulated secretion and fine tuning of GABA-signaling in islets of Langerhans....

  3. DNA precursor compartmentation in mammalian cells: metabolic and antimetabolic studies of nuclear and mitochondrial DNA synthesis

    International Nuclear Information System (INIS)

    HeLa cells were used for the quantitation of cellular and mitochondrial deoxyribonucleoside triphosphate (dNTP) and ribonucleoside triphosphate (rNTP) pools and of changes in pools in response to treatment with the antimetabolites methotrexate (mtx) and 5-fluorodeoxyuridine (FUdR). Use of an enzymatic assay of dNTPs and of improved nucleotide extraction methods allowed quantitation of mitochondrial dNTP pools. All four mitochondrial dNTP pools expand following treatment with mtx or FUdR whereas cellular dTTP and dGTP pools are depleted. Mitochrondrial rNTP pools were also found to expand in response to these antimetabolites. Mouse L-cells were used to determine the relative contributions of an exogenously supplied precursor to nuclear and mitochrondrial DNA replication. Cells were labeled to near steady state specific activities with 32P-orthophosphate and subsequently labeled with [3H]uridine, a general pyrimidine precursor, in the continuing presence of 32P. Deoxyribonucleoside monophosphates derived from these DNAs were separated by HPLC and the 3H/32P ratio in each pyrimidine determined. The dCMP residues in mitochondrial DNA (mtDNA) were found to be derived exclusively from the exogenous supplied uridine. The dTMP residues from nuclear and mtDNA and the dCMP residues from nuclear DNA were seen to be synthesized partly from exogenous sources and partly from other sources, presumably de novo pyrimidine synthesis

  4. In Vivo HIV-1 Cell-to-Cell Transmission Promotes Multicopy Micro-compartmentalized Infection

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    Kenneth M. Law

    2016-06-01

    Full Text Available HIV-1 infection is enhanced by adhesive structures that form between infected and uninfected T cells called virological synapses (VSs. This mode of transmission results in the frequent co-transmission of multiple copies of HIV-1 across the VS, which can reduce sensitivity to antiretroviral drugs. Studying HIV-1 infection of humanized mice, we measured the frequency of co-transmission and the spatiotemporal organization of infected cells as indicators of cell-to-cell transmission in vivo. When inoculating mice with cells co-infected with two viral genotypes, we observed high levels of co-transmission to target cells. Additionally, micro-anatomical clustering of viral genotypes within lymphoid tissue indicates that viral spread is driven by local processes and not a diffuse viral cloud. Intravital splenic imaging reveals that anchored HIV-infected cells induce arrest of interacting, uninfected CD4+ T cells to form Env-dependent cell-cell conjugates. These findings suggest that HIV-1 spread between immune cells can be anatomically localized into infectious clusters.

  5. Simultaneous 1H PFG-NMR and Confocal Microscopy of Monolayer Cell Cultures: Effects of Apoptosis and Necrosis on Water Diffusion and Compartmentalization

    Energy Technology Data Exchange (ETDEWEB)

    Minard, Kevin R.; Holtom, Gary R.; Kathmann, Loel E.; Majors, Paul D.; Thrall, Brian D.; Wind, Robert A.

    2004-09-01

    Apoptosis and necrosis is induced in monolayer cultures of Chinese hamster ovary cells using okadaic acid and hydrogen peroxide (H2O2) respectively, and the effect on water diffusion and compartmentalization is examined using pulsed-field-gradient (PFG) 1H-NMR and simultaneous confocal microscopy. In PFG experiments characterized by a fixed diffusion time (< 4.7 msec) and variable b-values (0-27,000 s/mm2) 1H-NMR data collected with untreated cells exhibits multi-exponential behavior. Analysis using a slow-exchange model reveals two distinct cellular water compartments with different apparent diffusion coefficients (0.56, 0.06 x 10-3 mm2/sec) and volume fractions (0.96, 0.04). During the first 12 hours of either necrosis or apoptosis the amount of water in the smallest compartment increases two-fold prior to significant changes in cell density or plasma membrane integrity. Over the same period water content in the largest compartment decreases by over a factor of two in apoptotic cells, in accordance with observed cell shrinkage, and changes little in necrotic counterparts where only slight swelling is evident. PFG 1H-NMR therefore serves as a sensitive indicator of early cell death in monolayer cultures and can distinguish apoptosis from necrosis. Measurements of restricted diffusion and water exchange are also presented to elucidate compartment origins and justify model assumptions.

  6. Current Ideas about Prebiological Compartmentalization

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    Pierre-Alain Monnard

    2015-04-01

    Full Text Available Contemporary biological cells are highly sophisticated dynamic compartment systems which separate an internal volume from the external medium through a boundary, which controls, in complex ways, the exchange of matter and energy between the cell’s interior and the environment. Since such compartmentalization is a fundamental principle of all forms of life, scenarios have been elaborated about the emergence of prebiological compartments on early Earth, in particular about their likely structural characteristics and dynamic features. Chemical systems that consist of potentially prebiological compartments and chemical reaction networks have been designed to model pre-cellular systems. These systems are often referred to as “protocells”. Past and current protocell model systems are presented and compared. Since the prebiotic formation of cell-like compartments is directly linked to the prebiotic availability of compartment building blocks, a few aspects on the likely chemical inventory on the early Earth are also summarized.

  7. Functional compartmentation of the Golgi apparatus of plant cells : immunocytochemical analysis of high-pressure frozen- and freeze-substituted sycamore maple suspension culture cells.

    Science.gov (United States)

    Zhang, G F; Staehelin, L A

    1992-07-01

    The Golgi apparatus of plant cells is engaged in both the processing of glycoproteins and the synthesis of complex polysaccharides. To investigate the compartmentalization of these functions within individual Golgi stacks, we have analyzed the ultrastructure and the immunolabeling patterns of high-pressure frozen and freeze-substituted suspension-cultured sycamore maple (Acer pseudoplatanus L.) cells. As a result of the improved structural preservation, three morphological types of Golgi cisternae, designated cis, medial, and trans, as well as the trans Golgi network, could be identified. The number of cis cisternae per Golgi stack was found to be fairly constant at approximately 1, whereas the number of medial and trans cisternae per stack was variable and accounted for the varying number of cisternae (3-10) among the many Golgi stacks examined. By using a battery of seven antibodies whose specific sugar epitopes on secreted polysaccharides and glycoproteins are known, we have been able to determine in which types of cisternae specific sugars are added to N-linked glycans, and to xyloglucan and polygalacturonic acid/rhamnogalacturonan-I, two complex polysaccharides. The findings are as follows. The beta-1,4-linked d-glucosyl backbone of xyloglucan is synthesized in trans cisternae, and the terminal fucosyl residues on the trisaccharide side chains of xyloglucan are partly added in the trans cisternae, and partly in the trans Golgi network. In contrast, the polygalacturonic/rhamnogalacturonan-I backbone is assembled in cis and medial cisternae, methylesterification of the carboxyl groups of the galacturonic acid residues in the polygalacturonic acid domains occurs mostly in medial cisternae, and arabinose-containing side chains of the polygalacturonic acid domains are added to the nascent polygalacturonic acid/rhamnogalacturonan-I molecules in the trans cisternae. Double labeling experiments demonstrate that xyloglucan and polygalacturonic acid

  8. Protocell design through modular compartmentalization

    Science.gov (United States)

    Miller, David; Booth, Paula J.; Seddon, John M.; Templer, Richard H.; Law, Robert V.; Woscholski, Rudiger; Ces, Oscar; Barter, Laura M. C.

    2013-01-01

    De novo synthetic biological design has the potential to significantly impact upon applications such as energy generation and nanofabrication. Current designs for constructing organisms from component parts are typically limited in scope, as they utilize a cut-and-paste ideology to create simple stepwise engineered protein-signalling pathways. We propose the addition of a new design element that segregates components into lipid-bound ‘proto-organelles’, which are interfaced with response elements and housed within a synthetic protocell. This design is inspired by living cells, which utilize multiple types of signalling molecules to facilitate communication between isolated compartments. This paper presents our design and validation of the components required for a simple multi-compartment protocell machine, for coupling a light transducer to a gene expression system. This represents a general design concept for the compartmentalization of different types of artificial cellular machinery and the utilization of non-protein signal molecules for signal transduction. PMID:23925982

  9. Lysine-specific demethylase-1 (LSD1) is compartmentalized at nuclear chromocenters in early post-mitotic cells of the olfactory sensory neuronal lineage.

    Science.gov (United States)

    Kilinc, Seda; Savarino, Alyssa; Coleman, Julie H; Schwob, James E; Lane, Robert P

    2016-07-01

    Mammalian olfaction depends on the development of specialized olfactory sensory neurons (OSNs) that each express one odorant receptor (OR) protein from a large family of OR genes encoded in the genome. The lysine-specific demethylase-1 (LSD1) protein removes activating H3K4 or silencing H3K9 methylation marks at gene promoters and is required for proper OR regulation. We show that LSD1 protein exhibits variable organization within nuclei of developing OSNs, and tends to consolidate into a single dominant compartment at the edges of chromocenters within nuclei of early post-mitotic cells of the mouse olfactory epithelium (MOE). Using an immortalized cell line derived from developing olfactory placode, we show that consolidation of LSD1 appears to be cell-cycle regulated, with a peak occurrence in early G1. LSD1 co-compartmentalizes with CoREST, a protein known to collaborate with LSD1 to carry out a variety of chromatin-modifying functions. We show that LSD1 compartments co-localize with 1-3 OR loci at the exclusion of most OR genes, and commonly associate with Lhx2, a transcription factor involved in OR regulation. Together, our data suggests that LSD1 is sequestered into a distinct nuclear space that might restrict a histone-modifying function to a narrow developmental time window and/or range of OR gene targets. PMID:26947098

  10. Vimentin compartmentalization in discoid lupus

    Directory of Open Access Journals (Sweden)

    Ana Maria Abreu-Velez

    2010-01-01

    Full Text Available Context: Discoid lupus erythematosus (DLE is a chronic skin condition, often presenting inflammatory, scarring lesions predominating on sun exposed areas of the face and scalp. Case Report: A 46-year-old black female was evaluated for possible DLE. Biopsies for hematoxylin and eosin (H&E and immunohistochemistry (IHC examination, as well as for direct immunofluorescence (DIF analysis were performed. The H&E staining demonstrated mild epidermal atrophy with focal follicular plugging. A mild interface infiltrate of lymphocytes and histiocytes and a superficial and deep, perivascular and periadnexal dermal infiltrate of lymphocytes, histiocytes and plasma cells was observed The DIF revealed strong deposits of immunoglobulins IgG, IgM, fibrinogen and Complement/C3, present in a granular pattern at the basement membrane junction (BMZ of the skin as well as in the BMZ of the sebaceous glands. In addition, deposits of IgA surrounding the superficial dermal blood vessels were appreciated. The IHC displayed compartmentalization of vimentin around the BMZ of both the superrficial skin and sebaceous gland BMZs, as well as similar patterns of deposits of the same immunoglobulins, complement, and fibrinogen as visualized by DIF. Conclusions : Minimal attention has been given to the process of compartmentalization of the dermis in inflammatory skin conditions, including DLE. However, it seems that in addition to the classical immunoglobulin and complement "lupus band" deposits at the BMZ, an additional, orchestrated immunologic reorganization of the dermis surrounding the inflammatory process is also present. Such an immunologic reorganization of the dermis could play a significant role in the pathophysiology of this disorder.

  11. Compartmentalized coculture of rat brain endothelial cells and astrocytes: a syngenic model to study the blood-brain barrier.

    Science.gov (United States)

    Demeuse, Ph; Kerkhofs, A; Struys-Ponsar, C; Knoops, B; Remacle, C; van den Bosch de Aguilar, Ph

    2002-11-15

    The specific structure of the blood-brain barrier (BBB) is based on the partnership of brain endothelial cells and astrocytes. In the last decade, cocultures of these two cell types have been developed as in vitro models. However, these studies did not allow close contacts between both cell types. We report here a syngenic coculture model using rat endothelial cells on one side of a polyethylene terephtalate filter and rat astrocytes on the other. Endothelial cells retain their typical morphology and are factor VIII and OX 26 positive. We optimized the diameter of the membrane pores to establish very close contacts between the cells through the membrane pores without mixing the two cell types. Transmission electron microscopy showed evidence of tight junction formation between the endothelial cells and few pinocytic vesicles. The cocultures reached high electrical resistances up to 1000 Omegacm(2) showing their ability to limit the passage of ions. A 15-fold increase in gamma-glutamyl transpeptidase activity was measured in the endothelial cells in coculture compared to endothelial cell monoculture. Our syngenic coculture represents a useful in vitro model of the rat BBB that may prove to be valuable for studying the passage of substances across the barrier as well as other aspects of the BBB function. PMID:12393158

  12. Expression and compartmentalization of caveolin in adipose cells: coordinate regulation with and structural segregation from GLUT4

    OpenAIRE

    1995-01-01

    Native rat adipocytes and the mouse adipocyte cell line, 3T3-L1, possess transport vesicles of apparently uniform composition and size which translocate the tissue-specific glucose transporter isoform, GLUT4, from an intracellular pool to the cell surface in an insulin- sensitive fashion. Caveolin, the presumed structural protein of caveolae, has also been proposed to function in vesicular transport. Thus, we studied the expression and subcellular distribution of caveolin in adipocytes. We fo...

  13. Compartmentation of hepatic fatty-acid-binding protein in liver cells and its effect on microsomal phosphatidic acid biosynthesis.

    Science.gov (United States)

    Bordewick, U; Heese, M; Börchers, T; Robenek, H; Spener, F

    1989-03-01

    Fatty-acid-binding proteins are known to occur in the cytosol of mammalian cells and to bind fatty acids and their CoA-esters. Application of the postembedding protein A-gold labeling method with antibody against the hepatic type fatty-acid-binding protein (hFABP) to cross-sections of liver cells and a newly developed gel-chromatographic immunofluorescence assay established qualitatively (1) that hFABP in mitochondria was confined to outer mitochondrial membranes, (2) the presence of this protein in microsomes and (3) that nuclei were also filled with hFABP. Quantitative data elaborated with a non-competitive ELISA confirmed these results. A significant difference to the distribution of cardiac FABP in heart muscle cells, where this type of protein was found in cytosol, matrix and nuclei, was observed (Börchers et al. (1989) Biochim. Biophys. Acta, in the press). hFABP-containing rat liver microsomes were incubated with long-chain acyl-CoAs in the presence of hFABP (isolated from rat liver cytosol) in a study on the acylation of sn-glycerol-3-phosphate and lysophosphatidic acid. Both acyltransferases were stimulated by addition of hFABP to the incubation medium. The morphological, immunochemical as well as kinetic data infer a direct interaction of hFABP with microsomal membranes in liver cells.

  14. Subcellular compartmentation of ascorbate and its variation in disease states.

    Science.gov (United States)

    Bánhegyi, Gábor; Benedetti, Angelo; Margittai, Eva; Marcolongo, Paola; Fulceri, Rosella; Németh, Csilla E; Szarka, András

    2014-09-01

    Beyond its general role as antioxidant, specific functions of ascorbate are compartmentalized within the eukaryotic cell. The list of organelle-specific functions of ascorbate has been recently expanded with the epigenetic role exerted as a cofactor for DNA and histone demethylases in the nucleus. Compartmentation necessitates the transport through intracellular membranes; members of the GLUT family and sodium-vitamin C cotransporters mediate the permeation of dehydroascorbic acid and ascorbate, respectively. Recent observations show that increased consumption and/or hindered entrance of ascorbate in/to a compartment results in pathological alterations partially resembling to scurvy, thus diseases of ascorbate compartmentation can exist. The review focuses on the reactions and transporters that can modulate ascorbate concentration and redox state in three compartments: endoplasmic reticulum, mitochondria and nucleus. By introducing the relevant experimental and clinical findings we make an attempt to coin the term of ascorbate compartmentation disease. PMID:24907663

  15. Performance of non-compartmentalized enzymatic biofuel cell based on buckypaper cathode and ferrocene-containing redox polymer anode

    Science.gov (United States)

    Bunte, Christine; Hussein, Laith; Urban, Gerald A.

    2014-02-01

    Novel single compartment Glucose/O2 biofuel cells (BFCs) were developed using immobilized enzymes and the mediated electron transfer (MET) approach. The bioanode was prepared through a ferrocene-containing redox polymer crosslinked in the presence of a biocatalyst on a glassy carbon support. Here, the redox polymer can physically entrap the enzyme and prevent it from leaching. Additionally it provides a biocompatible microenvironment and thus could extend the life time of enzyme. On the other side, the mediated biocathode was prepared based on bilirubin oxidase and 2,2‧-azinobis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS2-) system which has been physically entrapped in Nafion matrix and then adsorbed directly on a highly porous, conductive and functionalized buckypaper (fBP). Both electrodes were characterized physically and electrochemically. Employing these electrodes, the resulting BFC generates an open circuit voltage (Voc) of approximately 0.550 V and a peak power density of 26 μW cm-2 at 0.2 V at 37 °C in quiescent O2-saturated physiological buffer containing 5 mM glucose. The cell sustains a load up to 225 μA cm-2. Moreover, a high short circuit current (Isc) of 300 μA cm-2 is approached. This BFC can operate in mild conditions without using any toxic materials which makes it attractive for implantable devices.

  16. Studies in the compartmentalization of trace elements in the blood of patients with sickle cell anaemia using PIXE technique

    Energy Technology Data Exchange (ETDEWEB)

    Ojo, J.O. (Dept. of Physics, Obafemi Awolowo Univ., Ile-Ife (Nigeria)); Oluwole, A.F. (Dept. of Physics, Obafemi Awolowo Univ., Ile-Ife (Nigeria)); Durosinmi, M.A. (Dept. of Haematology and Immunology, Obafemi Awolowo Univ., Ile-Ife (Nigeria)); Arsed, W. (Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom)); Akanle, O.A. (Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom)); Spyrou, N.M. (Dept. of Physics, Univ. of Surrey, Guildford (United Kingdom))

    1993-06-01

    Concentrations of trace elements in the whole blood, plasma and erythrocytes of 77 individuals (20 carrying the HbSS genotype, 21 with HbAS and 36 with HbAA) were determined using a PIXE facility employing a 2 MeV proton beam. Up to 16 elements were detected in some or all of the samples. The skewness of elemental distribution was measured for each element in the three bloodflow compartments. Most of the essential elements, apart from selenium were distinctly packed in either the erythrocytes or the plasma. Results of the t-test employed to compare elemental values between sickle cell subjects and matched controls show similar patterns in the three compartments for some of the elements. The results are compared with previous work using INAA. (orig.)

  17. Shedding light on cell compartmentation in the candidate phylum Poribacteria by high resolution visualisation and transcriptional profiling

    Science.gov (United States)

    Jahn, Martin T.; Markert, Sebastian M.; Ryu, Taewoo; Ravasi, Timothy; Stigloher, Christian; Hentschel, Ute; Moitinho-Silva, Lucas

    2016-01-01

    Assigning functions to uncultivated environmental microorganisms continues to be a challenging endeavour. Here, we present a new microscopy protocol for fluorescence in situ hybridisation-correlative light and electron microscopy (FISH-CLEM) that enabled, to our knowledge for the first time, the identification of single cells within their complex microenvironment at electron microscopy resolution. Members of the candidate phylum Poribacteria, common and uncultivated symbionts of marine sponges, were used towards this goal. Cellular 3D reconstructions revealed bipolar, spherical granules of low electron density, which likely represent carbon reserves. Poribacterial activity profiles were retrieved from prokaryotic enriched sponge metatranscriptomes using simulation-based optimised mapping. We observed high transcriptional activity for proteins related to bacterial microcompartments (BMC) and we resolved their subcellular localisation by combining FISH-CLEM with immunohistochemistry (IHC) on ultra-thin sponge tissue sections. In terms of functional relevance, we propose that the BMC-A region may be involved in 1,2-propanediol degradation. The FISH-IHC-CLEM approach was proven an effective toolkit to combine -omics approaches with functional studies and it should be widely applicable in environmental microbiology. PMID:27796326

  18. Predictive potential of flux balance analysis of Saccharomyces cerevisiae using as optimization function combinations of cell compartmental objectives.

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo García Sánchez

    Full Text Available BACKGROUND: The main objective of flux balance analysis (FBA is to obtain quantitative predictions of metabolic fluxes of an organism, and it is necessary to use an appropriate objective function to guarantee a good estimation of those fluxes. METHODOLOGY: In this study, the predictive performance of FBA was evaluated, using objective functions arising from the linear combination of different cellular objectives. This approach is most suitable for eukaryotic cells, owing to their multiplicity of cellular compartments. For this reason, Saccharomyces cerevisiae was used as model organism, and its metabolic network was represented using the genome-scale metabolic model iMM904. As the objective was to evaluate the predictive performance from the FBA using the kind of objective function previously described, substrate uptake and oxygen consumption were the only input data used for the FBA. Experimental information about microbial growth and exchange of metabolites with the environment was used to assess the quality of the predictions. CONCLUSIONS: The quality of the predictions obtained with the FBA depends greatly on the knowledge of the oxygen uptake rate. For the most of studied classifications, the best predictions were obtained with "maximization of growth", and with some combinations that include this objective. However, in the case of exponential growth with unknown oxygen exchange flux, the objective function "maximization of growth, plus minimization of NADH production in cytosol, plus minimization of NAD(PH consumption in mitochondrion" gave much more accurate estimations of fluxes than the obtained with any other objective function explored in this study.

  19. Nonnegative and Compartmental Dynamical Systems

    CERN Document Server

    Haddad, Wassim M; Hui, Qing

    2010-01-01

    This comprehensive book provides the first unified framework for stability and dissipativity analysis and control design for nonnegative and compartmental dynamical systems, which play a key role in a wide range of fields, including engineering, thermal sciences, biology, ecology, economics, genetics, chemistry, medicine, and sociology. Using the highest standards of exposition and rigor, the authors explain these systems and advance the state of the art in their analysis and active control design. Nonnegative and Compartmental Dynamical Systems presents the most complete treatment available o

  20. Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

    International Nuclear Information System (INIS)

    The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing β-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. - Zinc contaminants translocated to symplast of aged leaves were detoxified by phytic acid ligands.

  1. Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. II. Zinc binding inside leaf cell organelles

    Energy Technology Data Exchange (ETDEWEB)

    Vollenweider, Pierre, E-mail: pierre.vollenweider@wsl.c [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Bernasconi, Petra [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Environmental Protection Office (AfU), Aabachstrasse 5, 6300 Zug (Switzerland); Gautschi, Hans-Peter [Centre for Microscopy and Image Analysis (CMI), University of Zurich, Gloriastrasse 30, 8006 Zuerich (Switzerland); Menard, Terry; Frey, Beat; Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

    2011-01-15

    The phytoextraction potential of plants for removing heavy metals from polluted soils is determined by their capacity to store contaminants in aboveground organs and complex them safely. In this study, the metal compartmentation, elemental composition of zinc deposits and zinc complexation within leaves from poplars grown on soil with mixed metal contamination was analysed combining several histochemical and microanalytical approaches. Zinc was the only heavy metal detected and was stored in several organelles in the form of globoid deposits showing {beta}-metachromasy. It was associated to oxygen anions and different cations, noteworthy phosphorous. The deposit structure, elemental composition and element ratios indicated that zinc was chelated by phytic acid ligands. Maturation processes in vacuolar vs. cytoplasmic deposits were suggested by differences in size and amounts of complexed zinc. Hence, zinc complexation by phytate contributed to metal detoxification and accumulation in foliage but could not prevent toxicity reactions therein. - Zinc contaminants translocated to symplast of aged leaves were detoxified by phytic acid ligands.

  2. 免疫系统区室化与上皮细胞局部微环境中的免疫调节作用%Compartmentalization of immune system and regulatory effects of epithelial cells in local microenvironment

    Institute of Scientific and Technical Information of China (English)

    张彦洁; 钟文伟; 刘伟; 许春娣; 夏振炜; 周同

    2011-01-01

    近年来,免疫系统区室化(compartmentalization of immune system)的概念逐渐引起了人们的重视.对各类免疫及非免疫器官中的免疫区室化现象进行深入研究,有助于进一步了解机体免疫系统、免疫应答以及免疫相关疾病的发病机制,并可提供新的应对策略.上皮细胞体内广泛分布,承载机体多种重要生理功能.它作为免疫防御首道防线参与免疫系统区室化形成,并在免疫反应局部微环境中,既可与免疫细胞相互作用发挥固有免疫调节作用,亦可通过自身转分化调节后续适应性免疫应答,在抵御及清除病原体入侵、调控局部炎症免疫反应以及促进组织损伤修复中,发挥了不可或缺的重要作用.病理状态下,上皮细胞又可能是免疫稳态失衡甚或肿瘤发生发展的关键因素.结合免疫系统区室化,对上皮细胞在局部微环境中的免疫调节作用作一综述,为免疫相关疾病的研究以及临床诊疗提供新的思路和策略.%Recently, compartmentalization of immune system has emerged as a new concept that attracts much attention. Further study and research in the phenomenon of immune compartmentalizaton in lymphoid and nonlymphoid organs will contribute to understand the human immune system, immunologic responses and pathogenesis of immune-related diseases, as well as provide new therapeutic strategies. The epithelial cells exist in a wide variety of tissues with multiple physiological functions. In the microenvironment where the immunologic responses take place, the epithelial cells not only act as the first barriers involed in formation of compartmentalization of immune system, but also play a role in innate immune regulation by cell-cell interation and regulate the subsequent adaptive immunity after transdifferentiation process. Thus, they have indispensable effects on eliminating pathogens, regulating local inflammatory reactions and promoting tissue regeneration. In

  3. Compartmental modeling and tracer kinetics

    CERN Document Server

    Anderson, David H

    1983-01-01

    This monograph is concerned with mathematical aspects of compartmental an­ alysis. In particular, linear models are closely analyzed since they are fully justifiable as an investigative tool in tracer experiments. The objective of the monograph is to bring the reader up to date on some of the current mathematical prob­ lems of interest in compartmental analysis. This is accomplished by reviewing mathematical developments in the literature, especially over the last 10-15 years, and by presenting some new thoughts and directions for future mathematical research. These notes started as a series of lectures that I gave while visiting with the Division of Applied ~1athematics, Brown University, 1979, and have developed in­ to this collection of articles aimed at the reader with a beginning graduate level background in mathematics. The text can be used as a self-paced reading course. With this in mind, exercises have been appropriately placed throughout the notes. As an aid in reading the material, the e~d of a ...

  4. Compartmentalization of the endoplasmic reticulum in the early C. elegans embryos.

    Science.gov (United States)

    Lee, Zuo Yen; Prouteau, Manoël; Gotta, Monica; Barral, Yves

    2016-09-12

    The one-cell Caenorhabditis elegans embryo is polarized to partition fate determinants between the cell lineages generated during its first division. Using fluorescence loss in photobleaching, we find that the endoplasmic reticulum (ER) of the C. elegans embryo is physically continuous throughout the cell, but its membrane is compartmentalized shortly before nuclear envelope breakdown into an anterior and a posterior domain, indicating that a diffusion barrier forms in the ER membrane between these two domains. Using mutants with disorganized ER, we show that ER compartmentalization is independent of the morphological transition that the ER undergoes in mitosis. In contrast, compartmentalization takes place at the position of the future cleavage plane in a par-3-dependent manner. Together, our data indicate that the ER membrane is compartmentalized in cells as diverse as budding yeast, mouse neural stem cells, and the early C. elegans embryo. PMID:27597753

  5. Compartmentation of glycogen metabolism revealed from 13C isotopologue distributions

    Directory of Open Access Journals (Sweden)

    Marin de Mas Igor

    2011-10-01

    Full Text Available Abstract Background Stable isotope tracers are used to assess metabolic flux profiles in living cells. The existing methods of measurement average out the isotopic isomer distribution in metabolites throughout the cell, whereas the knowledge of compartmental organization of analyzed pathways is crucial for the evaluation of true fluxes. That is why we accepted a challenge to create a software tool that allows deciphering the compartmentation of metabolites based on the analysis of average isotopic isomer distribution. Results The software Isodyn, which simulates the dynamics of isotopic isomer distribution in central metabolic pathways, was supplemented by algorithms facilitating the transition between various analyzed metabolic schemes, and by the tools for model discrimination. It simulated 13C isotope distributions in glucose, lactate, glutamate and glycogen, measured by mass spectrometry after incubation of hepatocytes in the presence of only labeled glucose or glucose and lactate together (with label either in glucose or lactate. The simulations assumed either a single intracellular hexose phosphate pool, or also channeling of hexose phosphates resulting in a different isotopic composition of glycogen. Model discrimination test was applied to check the consistency of both models with experimental data. Metabolic flux profiles, evaluated with the accepted model that assumes channeling, revealed the range of changes in metabolic fluxes in liver cells. Conclusions The analysis of compartmentation of metabolic networks based on the measured 13C distribution was included in Isodyn as a routine procedure. The advantage of this implementation is that, being a part of evaluation of metabolic fluxes, it does not require additional experiments to study metabolic compartmentation. The analysis of experimental data revealed that the distribution of measured 13C-labeled glucose metabolites is inconsistent with the idea of perfect mixing of hexose

  6. Compartmentalization of Aquaporins in the Human Intestine

    Directory of Open Access Journals (Sweden)

    Rajendram V. Rajnarayanan

    2008-06-01

    Full Text Available Improper localization of water channel proteins called aquaporins (AQP induce mucosal injury which is implicated in Crohn’s disease and ulcerative colitis. The amino acid sequences of AQP3 and AQP10 are 79% similar and belong to the mammalian aquaglyceroporin subfamily. AQP10 is localized on the apical compartment of the intestinal epithelium called the glycocalyx while AQP3 is selectively targeted to the basolateral membrane. Despite the high sequence similarity and evolutionary relatedness, the molecular mechanism involved in the polarity, selective targeting and function of AQP3 and AQP10 in the intestine is largely unknown. Our hypothesis is that the differential polarity and selective targeting of AQP3 and AQP10 in the intestinal epithelial cells is influenced by amino acid signal motifs. We performed sequence and structural alignments to determine differences in signals for localization and posttranslational glycosylation. The basolateral sorting motif “YRLL” is present in AQP3 but absent in AQP10; while Nglycosylation signals are present in AQP10 but absent in AQP3. Furthermore, the C-terminal region of AQP3 is longer compared to AQP10. The sequence and structural differences between AQP3 and AQP10 provide insights into the differential compartmentalization and function of these two aquaporins commonly expressed in human intestines.

  7. Phosphodiesterase 4 and compartmentalization of cyclic AMP signaling

    Institute of Scientific and Technical Information of China (English)

    WANG ZhengChao; SHI FangXiong

    2007-01-01

    Cyclic AMP (cAMP), as a second messenger, plays a critical role in cellular signaling transduction. However, it is not clear how this apparently identical cAMP signal induces divergent physiological responses. The potential explanation that cAMP signaling is compartmentalized was proposed by Buxton and Brunton twenty years ago. Compartmentalization of cAMP signaling allows spatially distinct pools of protein kinase A (PKA) to be differently activated. Research on cAMP signaling has regained impetus in many fields of life sciences due to the progress in understanding cAMP signaling complexity and functional diversity. The cAMP/PKA signaling compartments are maintained by A-kinase anchoring proteins (AKAPs) which bind PKA and other signaling proteins, and by PDEs which hydrolyse cAMP and thus terminate PKA activity. PDE4 enzymes belong to PDE superfamily and stand at a crossroad that allows them to integrate various signaling pathways with that of cAMP in spatially distinct compartments. In the current review, the nomenclature, taxonomy and gene expression of PDE4, and the system and region of its effect are described. In addition, the idiographic molecules, mechanisms, and regulation models of PDE4 are summarized. Furthermore, the important roles PDE4 plays in the maturation of rat granulosa cells and cAMP signaling compartmentalization are discussed.

  8. Enhanced detection with spectral imaging fluorescence microscopy reveals tissue- and cell-type-specific compartmentalization of surface-modified polystyrene nanoparticles

    OpenAIRE

    Kenesei, Kata; Murali, Kumarasamy; Czéh, Árpád; Piella, Jordi; Puntes, Victor; Madarász, Emília

    2016-01-01

    Background Precisely targeted nanoparticle delivery is critically important for therapeutic applications. However, our knowledge on how the distinct physical and chemical properties of nanoparticles determine tissue penetration through physiological barriers, accumulation in specific cells and tissues, and clearance from selected organs has remained rather limited. In the recent study, spectral imaging fluorescence microscopy was exploited for precise and rapid monitoring of tissue- and cell-...

  9. Establishment and maintenance of compartmental boundaries: role of contractile actomyosin barriers.

    Science.gov (United States)

    Monier, Bruno; Pélissier-Monier, Anne; Sanson, Bénédicte

    2011-06-01

    During animal development, tissues and organs are partitioned into compartments that do not intermix. This organizing principle is essential for correct tissue morphogenesis. Given that cell sorting defects during compartmentalization in humans are thought to cause malignant invasion and congenital defects such as cranio-fronto-nasal syndrome, identifying the molecular and cellular mechanisms that keep cells apart at boundaries between compartments is important. In both vertebrates and invertebrates, transcription factors and short-range signalling pathways, such as EPH/Ephrin, Hedgehog, or Notch signalling, govern compartmental cell sorting. However, the mechanisms that mediate cell sorting downstream of these factors have remained elusive for decades. Here, we review recent data gathered in Drosophila that suggest that the generation of cortical tensile forces at compartmental boundaries by the actomyosin cytoskeleton could be a general mechanism that inhibits cell mixing between compartments. PMID:21437644

  10. Subcellular compartmentalization of 1-methyl-4-phenylpyridinium with catecholamines in adrenal medullary chromaffin vesicles may explain the lack of toxicity to adrenal chromaffin cells

    Energy Technology Data Exchange (ETDEWEB)

    Reinhard, J.F. Jr.; Diliberto, E.J. Jr.; Viveros, O.H.; Daniels, A.J.

    1987-11-01

    Cultures of bovine adrenomedullary chromaffin cells accumulated 1-methyl-4-phenylpyridinium (MPP/sup +/) in a time- and concentration-dependent manner by a process that was prevented by desmethylimipramine. The subcellular localization of the incorporated (methyl-/sup 3/H)MPP/sup +/ was examined by differential centrifugation and sucrose density gradient fractionation and was found to be predominantly colocalized with catecholamines in chromaffin vesicles, and negligible amounts were detected within the mitochondrial fraction. When chromaffin cell membranes were made permeable with the detergent digitonin the absence of calcium, there was no increase in the release of (/sup 3/H)MPP/sup +/, indicating that there is negligible accumulation of the neurotoxin in the cytosol. Simultaneous exposure to digitonin and calcium induced cosecretion of MPP/sup +/ and catecholamines. Stimulation of the cells with nicotine released both catecholamines and MPP/sup +/ at identical rates and percentages of cellular content in a calcium-dependent manner. Last, when cells were incubated with MPP/sup +/ in the presence of tetrabenazine (an inhibitor of vesicular uptake), the chromaffin cell toxicity of MPP/sup +/ was potentiated. The authors submit that the ability of the chromaffin cells to take up and store MPP/sup +/ in the chromaffin vesicle prevents the toxin's interaction with other structures and, thus, prevents cell damage. As an extension of this hypothesis, the relative resistance of some brain monoaminergic neurons to the toxic actions of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine may result from the subcellular sequestration of MPP/sup +/ in the storage vesicle.

  11. Mitochondrial RNA granules: Compartmentalizing mitochondrial gene expression.

    Science.gov (United States)

    Jourdain, Alexis A; Boehm, Erik; Maundrell, Kinsey; Martinou, Jean-Claude

    2016-03-14

    In mitochondria, DNA replication, gene expression, and RNA degradation machineries coexist within a common nondelimited space, raising the question of how functional compartmentalization of gene expression is achieved. Here, we discuss the recently characterized "mitochondrial RNA granules," mitochondrial subdomains with an emerging role in the regulation of gene expression. PMID:26953349

  12. Expression of the Ly-6 family proteins Lynx1 and Ly6H in the rat brain is compartmentalized, cell-type specific, and developmentally regulated

    DEFF Research Database (Denmark)

    Thomsen, Morten Skøtt; Cinar, Betül; Jensen, Majbrit Myrup;

    2014-01-01

    The Ly-6 superfamily of proteins, which affects diverse processes in the immune system, has attracted renewed attention due to the ability of some Ly-6 proteins to bind to and modulate the function of neuronal nicotinic acetylcholine receptors (nAChRs). However, there is a scarcity of knowledge...... regarding the distribution and developmental regulation of these proteins in the brain. We use protein cross-linking and synaptosomal fractions to demonstrate that the Ly-6 proteins Lynx1 and Ly6H are membrane-bound proteins in the brain, which are present on the cell surface and localize to synaptic...... demonstrate that Lynx1 and Ly6H are expressed in cultured neurons, but not cultured micro- or astroglial cultures. In addition, Lynx1, but not Ly6H was detected in the CSF. Finally, we show that the Ly-6 proteins Lynx1, Lynx2, Ly6H, and PSCA, display distinct expression patterns during postnatal development...

  13. Intracellular compartmentalization of skeletal muscle glycogen metabolism and insulin signalling

    DEFF Research Database (Denmark)

    Prats Gavalda, Clara; Gomez-Cabello, Alba; Vigelsø Hansen, Andreas

    2011-01-01

    The interest in skeletal muscle metabolism and insulin signalling has increased exponentially in recent years as a consequence of their role in the development of type 2 diabetes mellitus. Despite this, the exact mechanisms involved in the regulation of skeletal muscle glycogen metabolism...... compartmentalization in the regulation of skeletal muscle glycogen metabolism and insulin signalling. As a result, a hypothetical regulatory mechanism is proposed by which cells could direct glycogen resynthesis towards different pools of glycogen particles depending on the metabolic needs. Furthermore, we discuss...... the role of skeletal muscle transverse tubules as potential modulators of tissue insulin responsiveness....

  14. Compartmentation of metals in foliage of Populus tremula grown on soils with mixed contamination. I. From the tree crown to leaf cell level

    Energy Technology Data Exchange (ETDEWEB)

    Vollenweider, Pierre, E-mail: pierre.vollenweider@wsl.c [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland); Menard, Terry; Guenthardt-Goerg, Madeleine S. [Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zuercherstrasse 111, 8903 Birmensdorf (Switzerland)

    2011-01-15

    In order to achieve efficient phytoextraction of heavy metals using trees, the metal allocation to aboveground tissues needs to be characterised. In his study, the distribution of heavy metals, macro- and micronutrients and the metal micro-localisation as a function of the leaf position and heavy metal treatment were analysed in poplars grown on soil with mixed metal contamination. Zinc was the most abundant contaminant in both soil and foliage and, together with cadmium, was preferentially accumulated in older foliage whereas excess copper and lead were not translocated. Changes in other element concentrations indicated an acceleration in aging as a consequence of the metal treatment. Excess zinc was irregularly accumulated inside leaf tissues, tended to saturate the veins and was more frequently stored in cell symplast than apoplast. Storage compartments including metabolically safe and sensitive subcellular sites resulted in sizable metal accumulation as well as stress reactions. - Within foliage of poplars growing on contaminated soils, Zinc was stored at metabolically safe as well as sensitive subcellular sites, ensuring sizable bioaccumulation but also causing injuries.

  15. Compartmentalization of bacteria in microcapsules.

    Science.gov (United States)

    van Wijk, Judith; Heunis, Tiaan; Harmzen, Elrika; Dicks, Leon M T; Meuldijk, Jan; Klumperman, Bert

    2014-12-18

    Lactobacillus plantarum strain 423 was encapsulated in hollow poly(organosiloxane) microcapsules by templating water-in-oil Pickering emulsion droplets via the interfacial reaction of alkylchlorosilanes. The bacteria were suspended in growth medium or buffer to protect the cells against pH changes during the interfacial reactions with alkylchlorosilanes. The results of this work open up novel avenues for the encapsulation of microbial cells.

  16. Super-resolution Microscopy Reveals Compartmentalization of Peroxisomal Membrane Proteins*

    Science.gov (United States)

    Galiani, Silvia; Waithe, Dominic; Reglinski, Katharina; Cruz-Zaragoza, Luis Daniel; Garcia, Esther; Clausen, Mathias P.; Schliebs, Wolfgang; Erdmann, Ralf; Eggeling, Christian

    2016-01-01

    Membrane-associated events during peroxisomal protein import processes play an essential role in peroxisome functionality. Many details of these processes are not known due to missing spatial resolution of technologies capable of investigating peroxisomes directly in the cell. Here, we present the use of super-resolution optical stimulated emission depletion microscopy to investigate with sub-60-nm resolution the heterogeneous spatial organization of the peroxisomal proteins PEX5, PEX14, and PEX11 around actively importing peroxisomes, showing distinct differences between these peroxins. Moreover, imported protein sterol carrier protein 2 (SCP2) occupies only a subregion of larger peroxisomes, highlighting the heterogeneous distribution of proteins even within the peroxisome. Finally, our data reveal subpopulations of peroxisomes showing only weak colocalization between PEX14 and PEX5 or PEX11 but at the same time a clear compartmentalized organization. This compartmentalization, which was less evident in cases of strong colocalization, indicates dynamic protein reorganization linked to changes occurring in the peroxisomes. Through the use of multicolor stimulated emission depletion microscopy, we have been able to characterize peroxisomes and their constituents to a yet unseen level of detail while maintaining a highly statistical approach, paving the way for equally complex biological studies in the future. PMID:27311714

  17. Compartmentalized ATP synthesis in skeletal muscle triads.

    Science.gov (United States)

    Han, J W; Thieleczek, R; Varsányi, M; Heilmeyer, L M

    1992-01-21

    Isolated skeletal muscle triads contain a compartmentalized glycolytic reaction sequence catalyzed by aldolase, triosephosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, and phosphoglycerate kinase. These enzymes express activity in the structure-associated state leading to synthesis of ATP in the triadic junction upon supply of glyceraldehyde 3-phosphate or fructose 1,6-bisphosphate. ATP formation occurs transiently and appears to be kinetically compartmentalized, i.e., the synthesized ATP is not in equilibrium with the bulk ATP. The apparent rate constants of the aldolase and the glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase reaction are significantly increased when fructose 1,6-bisphosphate instead of glyceraldehyde 3-phosphate is employed as substrate. The observations suggest that fructose 1,6-bisphosphate is especially effectively channelled into the junctional gap. The amplitude of the ATP transient is decreasing with increasing free [Ca2+] in the range of 1 nM to 30 microM. In the presence of fluoride, the ATP transient is significantly enhanced and its declining phase is substantially retarded. This observation suggests utilization of endogenously synthesized ATP in part by structure associated protein kinases and phosphatases which is confirmed by the detection of phosphorylated triadic proteins after gel electrophoresis and autoradiography. Endogenous protein kinases phosphorylate proteins of apparent Mr 450,000, 180,000, 160,000, 145,000, 135,000, 90,000, 54,000, 51,000, and 20,000, respectively. Some of these phosphorylated polypeptides are in the Mr range of known phosphoproteins involved in excitation-contraction coupling of skeletal muscle, which might give a first hint at the functional importance of the sequential glycolytic reactions compartmentalized in triads. PMID:1731894

  18. The mechanics of cellular compartmentalization as a model for tumor spreading

    Science.gov (United States)

    Fritsch, Anatol; Pawlizak, Steve; Zink, Mareike; Kaes, Josef A.

    2012-02-01

    Based on a recently developed surgical method of Michael H"ockel, which makes use of cellular confinement to compartments in the human body, we study the mechanics of the process of cell segregation. Compartmentalization is a fundamental process of cellular organization and occurs during embryonic development. A simple model system can demonstrate the process of compartmentalization: When two populations of suspended cells are mixed, this mixture will eventually segregate into two phases, whereas mixtures of the same cell type will not. In the 1960s, Malcolm S. Steinberg formulated the so-called differential adhesion hypothesis which explains the segregation in the model system and the process of compartmentalization by differences in surface tension and adhesiveness of the interacting cells. We are interested in to which extend the same physical principles affect tumor growth and spreading between compartments. For our studies, we use healthy and cancerous breast cell lines of different malignancy as well as primary cells from human cervix carcinoma. We apply a set of techniques to study their mechanical properties and interactions. The Optical Stretcher is used for whole cell rheology, while Cell-cell-adhesion forces are directly measured with a modified AFM. In combination with 3D segregation experiments in droplet cultures we try to clarify the role of surface tension in tumor spreading.

  19. Partitioning Variability of a Compartmentalized In Vitro Transcriptional Thresholding Circuit.

    Science.gov (United States)

    Kapsner, Korbinian; Simmel, Friedrich C

    2015-10-16

    Encapsulation of in vitro biochemical reaction circuits into small, cell-sized compartments can result in considerable variations in the dynamical properties of the circuits. As a model system, we here investigate a simple in vitro transcriptional reaction circuit, which generates an ultrasensitive fluorescence response when the concentration of an RNA transcript reaches a preset threshold. The reaction circuit is compartmentalized into spherical water-in-oil microemulsion droplets, and the reaction progress is monitored by fluorescence microscopy. A quantitative statistical analysis of thousands of individual droplets ranging in size from a few up to 20 μm reveals a strong variability in effective RNA production rates, which by computational modeling is traced back to a larger-than-Poisson variability in RNAP activities in the droplets. The noise level in terms of the noise strength (the Fano factor) is strongly dependent on the ratio between transcription templates and polymerases, and increases for higher template concentrations. PMID:25974035

  20. Fractional kinetics in multi-compartmental systems.

    Science.gov (United States)

    Dokoumetzidis, Aristides; Magin, Richard; Macheras, Panos

    2010-10-01

    Fractional calculus, the branch of calculus dealing with derivatives of non-integer order (e.g., the half-derivative) allows the formulation of fractional differential equations (FDEs), which have recently been applied to pharmacokinetics (PK) for one-compartment models. In this work we extend that theory to multi-compartmental models. Unlike systems defined by a single ordinary differential equation (ODE), considering fractional multi-compartmental models is not as simple as changing the order of the ordinary derivatives of the left-hand side of the ODEs to fractional orders. The latter may produce inconsistent systems which violate mass balance. We present a rationale for fractionalization of ODEs, which produces consistent systems and allows processes of different fractional orders in the same system. We also apply a method of solving such systems based on a numerical inverse Laplace transform algorithm, which we demonstrate that is consistent with analytical solutions when these are available. As examples of our approach, we consider two cases of a basic two-compartment PK model with a single IV dose and multiple oral dosing, where the transfer from the peripheral to the central compartment is of fractional order α < 1, accounting for anomalous kinetics and deep tissue trapping, while all other processes are of the usual order 1. Simulations with the studied systems are performed using the numerical inverse Laplace transform method. It is shown that the presence of a transfer rate of fractional order produces a non-exponential terminal phase, while multiple dose and constant infusion systems never reach steady state and drug accumulation carries on indefinitely. The IV fractional system is also fitted to PK data and parameter values are estimated. In conclusion, our approach allows the formulation of systems of FDEs, mixing different fractional orders, in a consistent manner and also provides a method for the numerical solution of these systems. PMID

  1. Human Lsg1 defines a family of essential GTPases that correlates with the evolution of compartmentalization

    Directory of Open Access Journals (Sweden)

    Scheffzek Klaus

    2005-10-01

    Full Text Available Abstract Background Compartmentalization is a key feature of eukaryotic cells, but its evolution remains poorly understood. GTPases are the oldest enzymes that use nucleotides as substrates and they participate in a wide range of cellular processes. Therefore, they are ideal tools for comparative genomic studies aimed at understanding how aspects of biological complexity such as cellular compartmentalization evolved. Results We describe the identification and characterization of a unique family of circularly permuted GTPases represented by the human orthologue of yeast Lsg1p. We placed the members of this family in the phylogenetic context of the YlqF Related GTPase (YRG family, which are present in Eukarya, Bacteria and Archea and include the stem cell regulator Nucleostemin. To extend the computational analysis, we showed that hLsg1 is an essential GTPase predominantly located in the endoplasmic reticulum and, in some cells, in Cajal bodies in the nucleus. Comparison of localization and siRNA datasets suggests that all members of the family are essential GTPases that have increased in number as the compartmentalization of the eukaryotic cell and the ribosome biogenesis pathway have evolved. Conclusion We propose a scenario, consistent with our data, for the evolution of this family: cytoplasmic components were first acquired, followed by nuclear components, and finally the mitochondrial and chloroplast elements were derived from different bacterial species, in parallel with the formation of the nucleolus and the specialization of nuclear components.

  2. The compartmentalized bacteria of the planctomycetes-verrucomicrobia-chlamydiae superphylum have membrane coat-like proteins.

    Directory of Open Access Journals (Sweden)

    Rachel Santarella-Mellwig

    2010-01-01

    Full Text Available The development of the endomembrane system was a major step in eukaryotic evolution. Membrane coats, which exhibit a unique arrangement of beta-propeller and alpha-helical repeat domains, play key roles in shaping eukaryotic membranes. Such proteins are likely to have been present in the ancestral eukaryote but cannot be detected in prokaryotes using sequence-only searches. We have used a structure-based detection protocol to search all proteomes for proteins with this domain architecture. Apart from the eukaryotes, we identified this protein architecture only in the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum, many members of which share a compartmentalized cell plan. We determined that one such protein is partly localized at the membranes of vesicles formed inside the cells in the planctomycete Gemmata obscuriglobus. Our results demonstrate similarities between bacterial and eukaryotic compartmentalization machinery, suggesting that the bacterial PVC superphylum contributed significantly to eukaryogenesis.

  3. Field Testing of Compartmentalization Methods for Multifamily Construction

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States); Lstiburek, J. W. [Building Science Corporation, Westford, MA (United States)

    2015-03-01

    The 2012 International Energy Conservation Code (IECC) has an airtightness requirement of 3 air changes per hour at 50 Pascals test pressure (3 ACH50) for single-family and multifamily construction (in climate zones 3–8). The Leadership in Energy & Environmental Design certification program and ASHRAE Standard 189 have comparable compartmentalization requirements. ASHRAE Standard 62.2 will soon be responsible for all multifamily ventilation requirements (low rise and high rise); it has an exceptionally stringent compartmentalization requirement. These code and program requirements are driving the need for easier and more effective methods of compartmentalization in multifamily buildings.

  4. Potassium fluxes in Chlamydomonas reinhardtii. II. Compartmental analysis

    International Nuclear Information System (INIS)

    42K+ and 86Rb+ were used to determine the subcellular distribution of potassium in Chlamydomonas reinhardtii by compartmental analysis. In both wild type and a mutant strain, three distinct compartments (referred to as I, II, and III) were apparent. Using 42K+, we found that these had half-lives for K+ exchange of 1.07 min, 12.8 min, and 2.9 h, respectively, in wild-type cells and 0.93 min, 14.7 min, and 9.8 h, respectively, for the mutants. Half-lives were not significantly different when 86Rb+ was used to trace K+. Compartments I and II probably correspond to the cell wall and cytoplasm, respectively. Based on the lack of a large central vacuole in Chlamydomonas, the effect of a dark pretreatment on the kinetic properties of compartment III and the similarity between the [K+] of compartment III and that of isolated chloroplasts, this slowly exchanging compartment was identified as the chloroplast. Growth of wild-type cells at 100 micromolars (instead of 10 mM K+) caused no change of cytoplasmic [K+] but reduced chloroplast [K+] very substantially. The mutants failed to grow at 100 micromolars K+

  5. p53 gene mutations, p53 protein accumulation and compartmentalization in colorectal adenocarcinoma.

    OpenAIRE

    Bosari, S.; Viale, G.; Roncalli, M; Graziani, D.; Borsani, G; Lee, A. K.; Coggi, G.

    1995-01-01

    p53 accumulation may occur in the nucleus and/or cytoplasm of neoplastic cells. Cytoplasmic accumulation has been reported to be an unfavorable, but not established, prognostic indicator in colorectal cancer. Different types of p53 intracellular compartmentalization could depend either on p53 gene mutations or on the interaction with p53 protein ligands. The purposes of our study were (1) to assess whether the different patterns of p53 accumulation are selectively associated with p53 mutation...

  6. Compartmentalization and Transport in Synthetic Vesicles

    Directory of Open Access Journals (Sweden)

    Christine eSchmitt

    2016-02-01

    Full Text Available Nano-scale vesicles have become a popular tool in life sciences. Besides liposomes that are generated from phospholipids of natural origin, polymersomes fabricated of synthetic block copolymers enjoy increasing popularity, as they represent more versatile membrane building blocks that can be selected based on their specific physicochemical properties, like permeability, stability or chemical reactivity.In this review, we focus on the application of simple and nested artificial vesicles in synthetic biology. First, we provide an introduction into the utilization of multi-compartmented vesosomes as compartmentalized nano-scale bioreactors. In the bottom-up development of protocells from vesicular nano-reactors, the specific exchange of pathway intermediates across compartment boundaries represents a bottleneck for future studies. To date, most compartmented bioreactors rely on unspecific exchange of substrates and products. This is either based on changes in permeability of the coblock polymer shell by physicochemical triggers or by the incorporation of unspecific porin proteins into the vesicle membrane. Since the incorporation of membrane transport proteins into simple and nested artificial vesicles offers the potential for specific exchange of substances between subcompartments, it opens new vistas in the design of protocells. Therefore we devote the main part of the review to summarize the technical advances in the use of phospholipids and block copolymers for the reconstitution of membrane proteins.

  7. A development-based compartmentalization of the Drosophila central brain

    Science.gov (United States)

    Pereanu, Wayne; Kumar, Abilasha; Jennett, Arnim; Reichert, Heinrich; Hartenstein, Volker

    2010-01-01

    The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells, as well as long neurite fascicles. These fascicles are formed during the larval period when the approximately 100 neuronal lineages that constitute the Drosophila central brain differentiate. Each lineage forms an axon tract with a characteristic trajectory in the neuropile; groups of spatially related tracts congregate into the brain fascicles that can be followed from the larva throughout metamorphosis into the adult stage. In this paper we provide a map of the adult brain compartments and the relevant fascicles defining compartmental boundaries. We have identified the neuronal lineages contributing to each fascicle, which allowed us to directly compare compartments of the larval and adult brain. Most adult compartments can be recognized already in the early larval brain where they form a “protomap” of the later adult compartments. Our analysis highlights the morphogenetic changes shaping the Drosophila brain; the data will be important for studies that link early acting genetic mechanisms to the adult neuronal structures and circuits controlled by these mechanisms. PMID:20533357

  8. Development-based compartmentalization of the Drosophila central brain.

    Science.gov (United States)

    Pereanu, Wayne; Kumar, Abilasha; Jennett, Arnim; Reichert, Heinrich; Hartenstein, Volker

    2010-08-01

    The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells as well as long neurite fascicles. These fascicles are formed during the larval period, when the approximately 100 neuronal lineages that constitute the Drosophila central brain differentiate. Each lineage forms an axon tract with a characteristic trajectory in the neuropile; groups of spatially related tracts congregate into the brain fascicles that can be followed from the larva throughout metamorphosis into the adult stage. Here we provide a map of the adult brain compartments and the relevant fascicles defining compartmental boundaries. We have identified the neuronal lineages contributing to each fascicle, which allowed us to compare compartments of the larval and adult brain directly. Most adult compartments can be recognized already in the early larval brain, where they form a "protomap" of the later adult compartments. Our analysis highlights the morphogenetic changes shaping the Drosophila brain; the data will be important for studies that link early-acting genetic mechanisms to the adult neuronal structures and circuits controlled by these mechanisms. PMID:20533357

  9. Compartmentalization of prostaglandins in the canine kidney

    Energy Technology Data Exchange (ETDEWEB)

    Morgan-Boyd, R.L.

    1986-01-01

    The kidney has been shown to synthesize all of the naturally occurring major prostaglandins which may be restricted to a discrete part of the kidney where their actions are physiologically important, such as the vascular compartment and the tubular compartment. In order to examine this concept of compartmentalization, the authors conducted a series of experiments to determine whether PGl/sub 2/, measured as 6-keto-pGF/sub 1..cap alpha../, produced in the kidney is restricted to the renal vascular compartment or whether it also has access to the tubular compartment. Experiments were performed in the pentobarbital-anesthetized dog. Increasing pre-glomerular levels of 6-keto-PFG/sub 1..cap alpha../ caused marked increases in both the urinary excretion and the renal venous outflow to 6-keto-PGF/sub 1..cap alpha../. When /sup 3/H-6-keto-PGF/sub 1..cap alpha../ was co-infused with inulin into the renal artery, 33% of the radioactivity and 23% of the inulin was recovered on first pass. With infusion of /sup 3/H-PGl/sub 2/ and inulin, 20% of the radioactivity and 28% of the inulin reached the urine on first pass. Radioactive PGl/sub 2/ appeared to be less filterable at the glomeruli than either /sup 3/H-6-keto-PGF/sub 1..cap alpha../ or inulin. In the final set of experiments, in which dogs were prepared for a ureteral stopped-flow study, the PGE/sub 2//U/P/sub In/ ratio a peak was observed proximal to the Na/sup +/ plateau but distal to the Na+ nadir. In light of the results from the stopped-flow study and the intrarenal infusion studies, they conclude that PGE/sub 2/ synthesized in the kidney enters both the renal and tubular compartments. In contrast, they find that 6-keto-PGF/sub 1..cap alpha../ of renal origin enters only the renal origin enters only the renal vascular compartment and not the tubular compartment.

  10. Drivers of compartmentalization in a Mediterranean pollination network

    DEFF Research Database (Denmark)

    Gonzalez, Ana M. Martin; Allesina, Stefano; Rodrigo, Anselm;

    2012-01-01

    We study compartmentalization in a Mediterranean pollination network using three different analytical approaches: unipartite modularity (UM), bipartite modularity (BM) and the group model (GM). Our objectives are to compare compartments obtained with these three approaches and to explore the role...... of several species attributes related to pollination syndromes, species phenology, abundance and connectivity in structuring compartmentalization. BM could not identify compartments in our network. By contrast, UM revealed four modules composed of plants and pollinators, and GM four groups of plants and five...... of pollinators. Phenology had a major influence on compartmentalization, and compartments (both UM and GM) had distinct phenophases. Compartments were also strongly characterized by species degree (number of connections) and betweenness centrality. These two attributes were highly related to each other...

  11. Micro-compartmentalized cultivation of cyanobacteria for mutant screening using glass slides with highly water-repellent mark

    Directory of Open Access Journals (Sweden)

    Sayuri Arai

    2014-12-01

    Full Text Available Photosynthetic microorganisms such as cyanobacteria have attracted attention for their potential to produce biofuels and biochemicals directly from CO2. Cell isolation by colony has conventionally been used for selecting target cells. Colony isolation methods require a significant amount of time for cultivation, and the colony-forming ratio is potentially low for cyanobacteria. Here, we overcome such limitations by encapsulating and culturing cells in droplets with an overlay of dodecane using glass slides printed with highly water-repellent mark. In the compartmentalized culture, the oil phase protects the small volume of culture medium from drying and increases the CO2 supply. Since a difference in cell growth was observed with and without the addition of antibiotics, this compartmentalized culture method could be a powerful tool for mutant selection.

  12. Compartmentation and complexation of metals in hyperaccumulator plants

    Science.gov (United States)

    Leitenmaier, Barbara; Küpper, Hendrik

    2013-01-01

    Hyperaccumulators are being intensely investigated. They are not only interesting in scientific context due to their “strange” behavior in terms of dealing with high concentrations of metals, but also because of their use in phytoremediation and phytomining, for which understanding the mechanisms of hyperaccumulation is crucial. Hyperaccumulators naturally use metal accumulation as a defense against herbivores and pathogens, and therefore deal with accumulated metals in very specific ways of complexation and compartmentation, different from non-hyperaccumulator plants and also non-hyperaccumulated metals. For example, in contrast to non-hyperaccumulators, in hyperaccumulators even the classical phytochelatin-inducing metal, cadmium, is predominantly not bound by such sulfur ligands, but only by weak oxygen ligands. This applies to all hyperaccumulated metals investigated so far, as well as hyperaccumulation of the metalloid arsenic. Stronger ligands, as they have been shown to complex metals in non-hyperaccumulators, are in hyperaccumulators used for transient binding during transport to the storage sites (e.g., nicotianamine) and possibly for export of Cu in Cd/Zn hyperaccumulators [metallothioneins (MTs)]. This confirmed that enhanced active metal transport, and not metal complexation, is the key mechanism of hyperaccumulation. Hyperaccumulators tolerate the high amount of accumulated heavy metals by sequestering them into vacuoles, usually in large storage cells of the epidermis. This is mediated by strongly elevated expression of specific transport proteins in various tissues from metal uptake in the shoots up to the storage sites in the leaf epidermis. However, this mechanism seems to be very metal specific. Non-hyperaccumulated metals in hyperaccumulators seem to be dealt with like in non-hyperaccumulator plants, i.e., detoxified by binding to strong ligands such as MTs. PMID:24065978

  13. Compartmentation and complexation of metals in hyperaccumulator plants

    Directory of Open Access Journals (Sweden)

    Barbara eLeitenmaier

    2013-09-01

    Full Text Available Hyperaccumulators are being intensely investigated. They are not only interesting in scientific context due to their strange behaviour in terms of dealing with high concentrations of metals, but also because of their use in phytoremediation and phytomining, for which understanding the mechanisms of hyperaccumulation is crucial. Hyperaccumulators naturally use metal accumulation as a defence against herbivores and pathogens, and therefore deal with accumulated metals in very specific ways of complexation and compartmentation, different from non-hyperaccumulator plants and also non-hyperaccumulated metals. For example, in contrast to non-hyperaccumulators, in hyperaccumulators even the classical phytochelatin-inducing metal, cadmium, is predominantly not bound by such sulfur ligands, but only by weak oxygen ligands. This applies to all hyperaccumulated metals investigated so far, as well as hyperaccumulation of the metalloid arsenic. Stronger ligands, as they have been shown to complex metals in non-hyperaccumulators, are in hyperaccumulators used for transient binding during transport to the storage sites. This confirmed that enhanced active metal transport, and not metal complexation, is the key mechanism of hyperaccumulation. Hyperaccumulators tolerate the high amount of accumulated heavy metals by sequestering them into vacuoles, usually in large storage cells of the epidermis. This is mediated by strongly elevated expression of specific transport proteins in various tissues from metal uptake in the shoots up to the storage sites in the leaf epidermis. However, this mechanism seems to be very metal specific. Non-hyperaccumulated metals in hyperaccumulators seem to be dealt with like in non-hyperaccumulator plants, i.e. detoxified by binding to strong ligands such as metallothioneins.

  14. Barriers in the Brain: Resolving Dendritic Spine Morphology and Compartmentalization

    Directory of Open Access Journals (Sweden)

    Max eAdrian

    2014-12-01

    Full Text Available Dendritic spines are micron-sized protrusions that harbor the majority of excitatory synapses in the central nervous system. The head of the spine is connected to the dendritic shaft by a 50-400 nm thin membrane tube, called the spine neck, which has been hypothesized to confine biochemical and electric signals within the spine compartment. Such compartmentalization could minimize interspinal crosstalk and thereby support spine-specific synapse plasticity. However, to what extent compartmentalization is governed by spine morphology, and in particular the diameter of the spine neck, has remained unresolved. Here, we review recent advances in tool development - both experimental and theoretical - that facilitate studying the role of the spine neck in compartmentalization. Special emphasis is given to recent advances in microscopy methods and quantitative modeling applications as we discuss compartmentalization of biochemical signals, membrane receptors and electrical signals in spines. Multidisciplinary approaches should help to answer how dendritic spine architecture affects the cellular and molecular processes required for synapse maintenance and modulation.

  15. A Calculus for Modelling, Simulating and Analysing Compartmentalized Biological Systems

    DEFF Research Database (Denmark)

    Mardare, Radu Iulian; Ihekwaba, Adoha

    2007-01-01

    A. Ihekwaba, R. Mardare. A Calculus for Modelling, Simulating and Analysing Compartmentalized Biological Systems. Case study: NFkB system. In Proc. of International Conference of Computational Methods in Sciences and Engineering (ICCMSE), American Institute of Physics, AIP Proceedings, N 2...

  16. Subcellular compartmentalization of docking protein-1 contributes to progression in colorectal cancer.

    Science.gov (United States)

    Friedrich, Teresa; Söhn, Michaela; Gutting, Tobias; Janssen, Klaus-Peter; Behrens, Hans-Michael; Röcken, Christoph; Ebert, Matthias P A; Burgermeister, Elke

    2016-06-01

    Full-length (FL) docking protein-1 (DOK1) is an adapter protein which inhibits growth factor and immune response pathways in normal tissues, but is frequently lost in human cancers. Small DOK1 variants remain in cells of solid tumors and leukemias, albeit, their functions are elusive. To assess the so far unknown role of DOK1 in colorectal cancer (CRC), we generated DOK1 mutants which mimic the domain structure and subcellular distribution of DOK1 protein variants in leukemia patients. We found that cytoplasmic DOK1 activated peroxisome-proliferator-activated-receptor-gamma (PPARγ) resulting in inhibition of the c-FOS promoter and cell proliferation, whereas nuclear DOK1 was inactive. PPARγ-agonist increased expression of endogenous DOK1 and interaction with PPARγ. Forward translation of this cell-based signaling model predicted compartmentalization of DOK1 in patients. In a large series of CRC patients, loss of DOK1 protein was associated with poor prognosis at early tumor stages (*p=0.001; n=1492). In tumors with cytoplasmic expression of DOK1, survival was improved, whereas nuclear localization of DOK1 correlated with poor outcome, indicating that compartmentalization of DOK1 is critical for CRC progression. Thus, DOK1 was identified as a prognostic factor for non-metastatic CRC, and, via its drugability by PPARγ-agonist, may constitute a potential target for future cancer treatments. PMID:27428427

  17. Vacuolar compartmentalization as indispensable component of heavy metal detoxification in plants.

    Science.gov (United States)

    Sharma, Shanti S; Dietz, Karl-Josef; Mimura, Tetsuro

    2016-05-01

    Plant cells orchestrate an array of molecular mechanisms for maintaining plasmatic concentrations of essential heavy metal (HM) ions, for example, iron, zinc and copper, within the optimal functional range. In parallel, concentrations of non-essential HMs and metalloids, for example, cadmium, mercury and arsenic, should be kept below their toxicity threshold levels. Vacuolar compartmentalization is central to HM homeostasis. It depends on two vacuolar pumps (V-ATPase and V-PPase) and a set of tonoplast transporters, which are directly driven by proton motive force, and primary ATP-dependent pumps. While HM non-hyperaccumulator plants largely sequester toxic HMs in root vacuoles, HM hyperaccumulators usually sequester them in leaf cell vacuoles following efficient long-distance translocation. The distinct strategies evolved as a consequence of organ-specific differences particularly in vacuolar transporters and in addition to distinct features in long-distance transport. Recent molecular and functional characterization of tonoplast HM transporters has advanced our understanding of their contribution to HM homeostasis, tolerance and hyperaccumulation. Another important part of the dynamic vacuolar sequestration syndrome involves enhanced vacuolation. It involves vesicular trafficking in HM detoxification. The present review provides an updated account of molecular aspects that contribute to the vacuolar compartmentalization of HMs. PMID:26729300

  18. Quasi-steady state reduction for compartmental systems

    Science.gov (United States)

    Goeke, Alexandra; Lax, Christian

    2016-07-01

    We present a method to determine an asymptotic reduction (in the sense of Tikhonov and Fenichel) for singularly perturbed compartmental systems in the presence of slow transport. It turns out that the reduction can be derived from the individual interaction terms alone. We apply the result to spatially discretized reaction-diffusion systems and obtain (based on the reduced discretized systems) a heuristic to reduce reaction-diffusion systems in presence of slow diffusion.

  19. A Novel Method for Performance Analysis of Compartmentalized Reservoirs

    Directory of Open Access Journals (Sweden)

    Shahamat Mohammad Sadeq

    2016-05-01

    Full Text Available This paper presents a simple analytical model for performance analysis of compartmentalized reservoirs producing under Constant Terminal Rate (CTR and Constant Terminal Pressure (CTP. The model is based on the well-known material balance and boundary dominated flow equations and is written in terms of capacitance and resistance of a production and a support compartment. These capacitance and resistance terms account for a combination of reservoir parameters which enable the developed model to be used for characterizing such systems. In addition to considering the properties contrast between the two reservoir compartments, the model takes into account existence of transmissibility barriers with the use of resistance terms. The model is used to analyze production performance of unconventional reservoirs, where the multistage fracturing of horizontal wells effectively creates a Stimulated Reservoir Volume (SRV with an enhanced permeability surrounded by a non-stimulated region. It can also be used for analysis of compartmentalized conventional reservoirs. The analytical solutions provide type curves through which the controlling reservoirs parameters of a compartmentalized system can be estimated. The contribution of the supporting compartment is modeled based on a boundary dominated flow assumption. The transient behaviour of the support compartment is captured by application of “distance of investigation” concept. The model shows that depletion of the production and support compartments exhibit two unit slopes on a log-log plot of pressure versus time for CTR. For CTP, however, the depletions display two exponential declines. The depletion signatures are separated by transition periods, which depend on the contribution of the support compartment (i.e. transient or boundary dominated flow. The developed equations can be implemented easily in a spreadsheet application, and are corroborated with the use of a numerical simulation. The study

  20. Molecular Mechanisms of Compartmentalization and Biomineralization in Magnetotactic Bacteria

    OpenAIRE

    Komeili, Arash

    2012-01-01

    Magnetotactic bacteria are remarkable organisms with the ability to exploit the earth’s magnetic field for navigational purposes. To do this, they build specialized compartments called magnetosomes that consist of a lipid membrane and a crystalline magnetic mineral. These organisms have the potential to serve as models for the study of compartmentalization as well as biomineralization in bacteria. Additionally, they offer the opportunity to design applications that take advantage of the parti...

  1. Compartmentalized Droplets for Continuous Flow Liquid-Liquid Interface Catalysis.

    Science.gov (United States)

    Zhang, Ming; Wei, Lijuan; Chen, Huan; Du, Zhiping; Binks, Bernard P; Yang, Hengquan

    2016-08-17

    To address the limitations of batch organic-aqueous biphasic catalysis, we develop a conceptually novel method termed Flow Pickering Emulsion, or FPE, to process biphasic reactions in a continuous flow fashion. This method involves the compartmentalization of bulk water into micron-sized droplets based on a water-in-oil Pickering emulsion, which are packed into a column reactor. The compartmentalized water droplets can confine water-soluble catalysts, thus "immobilizing" the catalyst in the column reactor, while the interstices between the droplets allow the organic (oil) phase to flow. Key fundamental principles underpinning this method such as the oil phase flow behavior, the stability of compartmentalized droplets and the confinement capability of these droplets toward water-soluble catalysts are experimentally and theoretically investigated. As a proof of this concept, case studies including a sulfuric acid-catalyzed addition reaction, a heteropolyacid-catalyzed ring opening reaction and an enzyme-catalyzed chiral reaction demonstrate the generality and versatility of the FPE method. Impressively, in addition to the excellent durability, the developed FPE reactions exhibit up to 10-fold reaction efficiency enhancement in comparison to the existing batch reactions, indicating a unique flow interface catalysis effect. This study opens up a new avenue to allow conventional biphasic catalysis reactions to access more sustainable and efficient flow chemistry using an innovative liquid-liquid interface protocol. PMID:27429173

  2. Field Testing of Compartmentalization Methods for Multifamily Construction

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Westford, MA (United States); Lstiburek, J. [Building Science Corporation, Westford, MA (United States)

    2015-03-01

    The 2012 IECC has an airtightness requirement of 3 air changes per hour at 50 Pascals test pressure for both single-family and multifamily construction in Climate Zones 3-8. Other programs (LEED, ASHRAE 189, ASHRAE 62.2) have similar or tighter compartmentalization requirements, driving the need for easier and more effective methods of compartmentalization in multifamily buildings. Builders and practitioners have found that fire-resistance rated wall assemblies are a major source of difficulty in air sealing/compartmentalization, particularly in townhouse construction. This problem is exacerbated when garages are “tucked in” to the units and living space is located over the garages. In this project, Building Science Corporation examined the taping of exterior sheathing details to improve air sealing results in townhouse and multifamily construction, when coupled with a better understanding of air leakage pathways. Current approaches are cumbersome, expensive, time consuming, and ineffective; these details were proposed as a more effective and efficient method. The effectiveness of these air sealing methods was tested with blower door testing, including “nulled” or “guarded” testing (adjacent units run at equal test pressure to null out inter-unit air leakage, or “pressure neutralization”). Pressure diagnostics were used to evaluate unit-to-unit connections and series leakage pathways (i.e., air leakage from exterior, into the fire-resistance rated wall assembly, and to the interior).

  3. Polarity and intracellular compartmentalization of Drosophila neurons

    Directory of Open Access Journals (Sweden)

    Henner Astra L

    2007-04-01

    Full Text Available Abstract Background Proper neuronal function depends on forming three primary subcellular compartments: axons, dendrites, and soma. Each compartment has a specialized function (the axon to send information, dendrites to receive information, and the soma is where most cellular components are produced. In mammalian neurons, each primary compartment has distinctive molecular and morphological features, as well as smaller domains, such as the axon initial segment, that have more specialized functions. How neuronal subcellular compartments are established and maintained is not well understood. Genetic studies in Drosophila have provided insight into other areas of neurobiology, but it is not known whether flies are a good system in which to study neuronal polarity as a comprehensive analysis of Drosophila neuronal subcellular organization has not been performed. Results Here we use new and previously characterized markers to examine Drosophila neuronal compartments. We find that: axons and dendrites can accumulate different microtubule-binding proteins; protein synthesis machinery is concentrated in the cell body; pre- and post-synaptic sites localize to distinct regions of the neuron; and specializations similar to the initial segment are present. In addition, we track EB1-GFP dynamics and determine microtubules in axons and dendrites have opposite polarity. Conclusion We conclude that Drosophila will be a powerful system to study the establishment and maintenance of neuronal compartments.

  4. Laboratory of Cell and Molecular Biology

    Data.gov (United States)

    Federal Laboratory Consortium — The Laboratory of Cell and Molecular Biology investigates the organization, compartmentalization, and biochemistry of eukaryotic cells and the pathology associated...

  5. Evidence of vacuolar compartmentalization of arsenic in the hyperaccumulator Pteris vittata

    Institute of Scientific and Technical Information of China (English)

    YANG XueXi; CHEN Hui; DAI XiaoJing; XU WenZhong; HE ZhenYan; MA Mi

    2009-01-01

    Pteris vittata can hyperaccumulate arsenic (As) to>1% of its dry weight without showing any signs of toxicity,indicating the existence of effective plant-internal detoxification mechanisms.Although vacuolar compartmentalization is known to play an important role in heavy metal detoxification and tolerance,direct evidence of arsenic compartmentalization in this hyperaccumulator was lacking.Here we report the subcellular localization of As in the callus of P.vittata.The callus induced from gametophytes of P.vittata exposed to 0.2 mmol/L arsenate for 20 days were examined by directly isolating cell walls,protoplasts and vacuoles,and determining arsenic concentrations.Of the total As in the callus,about 94% was in the protoplast,and of that,91% was present in the vacuoles,indicating that vacuoles are a major storage site for As in P.vittata.In addition,the changes in the chemical components of vacuoles were analyzed by Fourier transform infrared spectroscopy (FTIR).

  6. Cellular compartmentation of cadmium and zinc in relation to other elements in the hyperaccumulator Arabidopsis halleri.

    Science.gov (United States)

    Küpper, H; Lombi, E; Zhao, F J; McGrath, S P

    2000-12-01

    The cellular compartmentation of elements was analysed in the Zn hyperaccumulator Arabidopsis halleri (L.) O'Kane & Al-Shehbaz (=Cardaminopsis halleri) using energy-dispersive X-ray microanalysis of frozen-hydrated tissues. Quantitative data were obtained using oxygen as an internal standard in the analyses of vacuoles, whereas a peak/background ratio method was used for quantification of elements in pollen and dehydrated trichomes. Arabidopsis halleri was found to hyperaccumulate not only Zn but also Cd in the shoot biomass. While large concentrations of Zn and Cd were found in the leaves and roots, flowers contained very little. In roots grown hydroponically, Zn and Cd accumulated in the cell wall of the rhizodermis (root epidermis), mainly due to precipitation of Zn/Cd phosphates. In leaves, the trichomes had by far the largest concentrations of Zn and Cd. Inside the trichomes there was a striking sub-cellular compartmentation, with almost all the Zn and Cd being accumulated in a narrow ring in the trichome base. This distribution pattern was very different from that for Ca and P. The epidermal cells other than trichomes were very small and contained lower concentrations of Zn and Cd than mesophyll cells. In particular, the concentrations of Cd and Zn in the mesophyll cells increased markedly in response to increasing Zn and Cd concentrations in the nutrient solution. This indicates that the mesophyll cells in the leaves of A. halleri are the major storage site for Zn and Cd, and play an important role in their hyperaccumulation. PMID:11219586

  7. Subcellular Compartmentalization and Trafficking of the Biosynthetic Machinery for Fungal Melanin.

    Science.gov (United States)

    Upadhyay, Srijana; Xu, Xinping; Lowry, David; Jackson, Jennifer C; Roberson, Robert W; Lin, Xiaorong

    2016-03-22

    Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell-wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are recruited to endosomes through a non-conventional secretory pathway. In contrast, late melanin enzymes accumulate in the cell wall. Such subcellular compartmentalization of the melanin biosynthetic machinery occurs in both A. fumigatus and A. nidulans. Thus, fungal melanin biosynthesis appears to be initiated in endosomes with exocytosis leading to melanin extracellular deposition, much like the synthesis and trafficking of mammalian melanin in endosomally derived melanosomes. PMID:26972005

  8. Subcellular Compartmentalization and Trafficking of the Biosynthetic Machinery for Fungal Melanin

    Directory of Open Access Journals (Sweden)

    Srijana Upadhyay

    2016-03-01

    Full Text Available Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs and how it is deposited as extracellular granules remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell-wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are recruited to endosomes through a non-conventional secretory pathway. In contrast, late melanin enzymes accumulate in the cell wall. Such subcellular compartmentalization of the melanin biosynthetic machinery occurs in both A. fumigatus and A. nidulans. Thus, fungal melanin biosynthesis appears to be initiated in endosomes with exocytosis leading to melanin extracellular deposition, much like the synthesis and trafficking of mammalian melanin in endosomally derived melanosomes.

  9. Analytical properties of a three-compartmental dynamical demographic model

    Science.gov (United States)

    Postnikov, E. B.

    2015-07-01

    The three-compartmental demographic model by Korotaeyv-Malkov-Khaltourina, connecting population size, economic surplus, and education level, is considered from the point of view of dynamical systems theory. It is shown that there exist two integrals of motion, which enables the system to be reduced to one nonlinear ordinary differential equation. The study of its structure provides analytical criteria for the dominance ranges of the dynamics of Malthus and Kremer. Additionally, the particular ranges of parameters enable the derived general ordinary differential equations to be reduced to the models of Gompertz and Thoularis-Wallace.

  10. Lower extremity compartmental anatomy: clinical relevance to radiologists

    Energy Technology Data Exchange (ETDEWEB)

    Toomayan, Glen A.; Robertson, Fabienne; Major, Nancy M. [Duke University Medical Center, Department of Radiology, Durham (United States)

    2005-06-01

    A thorough understanding of compartmental anatomy is necessary for the radiologist participating in the care of a patient with a lower extremity musculoskeletal malignancy. Localization of tumor to compartment of origin and identification of extracompartmental spread preoperatively are needed to correctly stage a tumor and determine the appropriate surgical management. An understanding of the locations of fascial boundaries, extracompartmental tissues, and neurovascular structures of the thigh and lower leg facilitates this diagnostic process. For the radiologist planning to biopsy a suspicious musculoskeletal lesion, consultation with the referring orthopaedic surgeon is recommended in order to jointly select an appropriate percutaneous biopsy approach. Adequate preprocedural planning ensures selection of an approach which prevents iatrogenic tumor spread beyond the compartment of origin, protects neurovascular structures, and allows complete resection of the biopsy tract and scar at the time of surgical resection without jeopardizing a potential limb-sparing procedure. Cross-sectional anatomic review and case examples demonstrate the importance of a detailed understanding of compartmental anatomy when approaching the patient with a lower extremity musculoskeletal tumor. (orig.)

  11. Directed evolution of polymerase function by compartmentalized self-replication.

    Science.gov (United States)

    Ghadessy, F J; Ong, J L; Holliger, P

    2001-04-10

    We describe compartmentalized self-replication (CSR), a strategy for the directed evolution of enzymes, especially polymerases. CSR is based on a simple feedback loop consisting of a polymerase that replicates only its own encoding gene. Compartmentalization serves to isolate individual self-replication reactions from each other. In such a system, adaptive gains directly (and proportionally) translate into genetic amplification of the encoding gene. CSR has applications in the evolution of polymerases with novel and useful properties. By using three cycles of CSR, we obtained variants of Taq DNA polymerase with 11-fold higher thermostability than the wild-type enzyme or with a >130-fold increased resistance to the potent inhibitor heparin. Insertion of an extra stage into the CSR cycle before the polymerase reaction allows its application to enzymes other than polymerases. We show that nucleoside diphosphate kinase and Taq polymerase can form such a cooperative CSR cycle based on reciprocal catalysis, whereby nucleoside diphosphate kinase produces the substrates required for the replication of its own gene. We also find that in CSR the polymerase genes themselves evolve toward more efficient replication. Thus, polymerase genes and their encoded polypeptides cooperate to maximize postselection copy number. CSR should prove useful for the directed evolution of enzymes, particularly DNA or RNA polymerases, as well as for the design and study of in vitro self-replicating systems mimicking prebiotic evolution and viral replication. PMID:11274352

  12. The monitoring of relative changes in compartmental compliances of brain

    International Nuclear Information System (INIS)

    The study aimed to develop a computational method for assessing relative changes in compartmental compliances within the brain: the arterial bed and the cerebrospinal space. The method utilizes the relationship between pulsatile components in the arterial blood volume, arterial blood pressure (ABP) and intracranial pressure (ICP). It was verified by using clinical recordings of intracranial pressure plateau waves, when massive vasodilatation accompanying plateau waves produces changes in brain compliances of the arterial bed (Ca) and compliance of the cerebrospinal space (Ci). Ten patients admitted after head injury with a median Glasgow Coma Score of 6 were studied retrospectively. ABP was directly monitored from the radial artery. Changes in the cerebral arterial blood volume were assessed using Transcranial Doppler (TCD) ultrasonography by digital integration of inflow blood velocity. During plateau waves, ICP increased (P = 0.001), CPP decreased (P = 0.001), ABP remained constant (P = 0.532), blood flow velocity decreased (P = 0.001). Calculated compliance of the arterial bed Ca increased significantly (P = 0.001); compliance of the CSF space Ci decreased (P = 0.001). We concluded that the method allows for continuous monitoring of relative changes in brain compartmental compliances. Plateau waves affect the balance between vascular and CSF compartments, which is reflected by the inverse change of compliance of the cerebral arterial bed and global compliance of the CSF space

  13. Membrane Compartmentalization Reducing the Mobility of Lipids and Proteins within a Model Plasma Membrane.

    Science.gov (United States)

    Koldsø, Heidi; Reddy, Tyler; Fowler, Philip W; Duncan, Anna L; Sansom, Mark S P

    2016-09-01

    The cytoskeleton underlying cell membranes may influence the dynamic organization of proteins and lipids within the bilayer by immobilizing certain transmembrane (TM) proteins and forming corrals within the membrane. Here, we present coarse-grained resolution simulations of a biologically realistic membrane model of asymmetrically organized lipids and TM proteins. We determine the effects of a model of cytoskeletal immobilization of selected membrane proteins using long time scale coarse-grained molecular dynamics simulations. By introducing compartments with varying degrees of restraints within the membrane models, we are able to reveal how compartmentalization caused by cytoskeletal immobilization leads to reduced and anomalous diffusional mobility of both proteins and lipids. This in turn results in a reduced rate of protein dimerization within the membrane and of hopping of membrane proteins between compartments. These simulations provide a molecular realization of hierarchical models often invoked to explain single-molecule imaging studies of membrane proteins.

  14. Multiple Facets of cAMP Signalling and Physiological Impact: cAMP Compartmentalization in the Lung

    Directory of Open Access Journals (Sweden)

    Martina Schmidt

    2012-11-01

    Full Text Available Therapies involving elevation of the endogenous suppressor cyclic AMP (cAMP are currently used in the treatment of several chronic inflammatory disorders, including chronic obstructive pulmonary disease (COPD. Characteristics of COPD are airway obstruction, airway inflammation and airway remodelling, processes encompassed by increased airway smooth muscle mass, epithelial changes, goblet cell and submucosal gland hyperplasia. In addition to inflammatory cells, airway smooth muscle cells and (myofibroblasts, epithelial cells underpin a variety of key responses in the airways such as inflammatory cytokine release, airway remodelling, mucus hypersecretion and airway barrier function. Cigarette smoke, being next to environmental pollution the main cause of COPD, is believed to cause epithelial hyperpermeability by disrupting the barrier function. Here we will focus on the most recent progress on compartmentalized signalling by cAMP. In addition to G protein-coupled receptors, adenylyl cyclases, cAMP-specific phospho-diesterases (PDEs maintain compartmentalized cAMP signalling. Intriguingly, spatially discrete cAMP-sensing signalling complexes seem also to involve distinct members of the A-kinase anchoring (AKAP superfamily and IQ motif containing GTPase activating protein (IQGAPs. In this review, we will highlight the interaction between cAMP and the epithelial barrier to retain proper lung function and to alleviate COPD symptoms and focus on the possible molecular mechanisms involved in this process. Future studies should include the development of cAMP-sensing multiprotein complex specific disruptors and/or stabilizers to orchestrate cellular functions. Compartmentalized cAMP signalling regulates important cellular processes in the lung and may serve as a therapeutic target.

  15. Building America Case Study: Field Testing of Compartmentalization Methods for Multifamily Construction (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2015-01-01

    The 2012 IECC has an airtightness requirement of 3 air changes per hour at 50 Pascals test pressure for both single family and multifamily construction in Climate Zones 3-8. Other programs (LEED, ASHRAE 189, ASHRAE 62.2) have similar or tighter compartmentalization requirements, thus driving the need for easier and more effective methods of compartmentalization in multifamily buildings.

  16. Direct calculation of leak path factors for highly compartmentalized buildings

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, M.T. [ITS Corp., Albuquerque, NM (United States); McClure, P.R. [Los Alamos National Lab., NM (United States)

    1998-12-01

    The large, highly compartmentalized configurations of buildings at many Department of Energy (DOE) facilities call the validity of traditional, simplistic methods for estimating contaminant leak path factors (LPFs) into question. Conversely, rigorous calculation of LPFs using detailed flow-field analysis computer codes is impractical for routine analysis. This paper describes a recent application of a rigorous, yet practical, method of calculating LPFs for the Chemical and Metallurgical Research (CMR) Facility at Los Alamos National Laboratory (LANL). The approach involves computer simulation of airborne contaminant transport using the MELCOR computer code. MELCOR is a general-purpose, fluid flow and aerosol transport analysis code originally developed by the US Nuclear Regulatory Commission to evaluate the release, transport, and deposition of radionuclides in nuclear reactor systems. However, the fundamental mathematical models in the code and the modular code architecture make it suitable to the CMR analysis.

  17. Apartment Compartmentalization With an Aerosol-Based Sealing Process

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, S. [Consortium for Advanced Residential Buildings, Norwalk, CT (United States); Berger, D. [Consortium for Advanced Residential Buildings, Norwalk, CT (United States); Harrington, C. [Consortium for Advanced Residential Buildings, Norwalk, CT (United States)

    2015-03-01

    Air sealing of building enclosures is a difficult and time-consuming process. Current methods in new construction require laborers to physically locate small and sometimes large holes in multiple assemblies and then manually seal each of them. The innovation demonstrated under this research study was the automated air sealing and compartmentalization of buildings through the use of an aerosolized sealant, developed by the Western Cooling Efficiency Center at University of California Davis. CARB sought to demonstrate this new technology application in a multifamily building in Queens, NY. The effectiveness of the sealing process was evaluated by three methods: air leakage testing of overall apartment before and after sealing, point-source testing of individual leaks, and pressure measurements in the walls of the target apartment during sealing.

  18. Compartmental analysis, imaging techniques and population pharmacokinetic. Experiences at CENTIS

    International Nuclear Information System (INIS)

    Introduction: In pharmacokinetic evaluation small rodents are used in a large extend. Traditional pharmacokinetic evaluations by the two steps approach can be replaced by the sparse data design which may also represent a complicated situation to evaluate satisfactorily from the statistical point of view. In this presentation different situations of sparse data sampling are analyzed based on practical consideration. Non linear mixed effect model was selected in order to estimate pharmacokinetic parameters in simulated data from real experimental results using blood sampling and imaging procedures. Materials and methods: Different scenarios representing several experimental designs of incomplete individual profiles were evaluated. Data sets were simulated based on real data from previous experiments. In all cases three to five blood samples were considered per time point. A combination of compartmental analysis with tumor uptake obtained by gammagraphy of radiolabeled drugs is also evaluated.All pharmacokinetic profiles were analyzed by means of MONOLIX software version 4.2.3. Results: All sampling schedules yield the same results when computed using the MONOLIX software and the SAEM algorithm. Population and individual pharmacokinetic parameters were accurately estimated with three or five determination per sampling point. According with the used methodology and software tool, it can be an expected result, but demonstrating the method performance in such situations, allow us to select a more flexible design using a very small number of animals in preclinical research. The combination with imaging procedures also allows us to construct a completely structured compartmental analysis. Results of real experiments are presented demonstrating the versatility of used methodology in different evaluations. The same sampling approach can be considered in phase I or II clinical trials. (author)

  19. Microfluidic device for the formation of optically excitable, three-dimensional, compartmentalized motor units.

    Science.gov (United States)

    Uzel, Sebastien G M; Platt, Randall J; Subramanian, Vidya; Pearl, Taylor M; Rowlands, Christopher J; Chan, Vincent; Boyer, Laurie A; So, Peter T C; Kamm, Roger D

    2016-08-01

    Motor units are the fundamental elements responsible for muscle movement. They are formed by lower motor neurons and their muscle targets, synapsed via neuromuscular junctions (NMJs). The loss of NMJs in neurodegenerative disorders (such as amyotrophic lateral sclerosis or spinal muscle atrophy) or as a result of traumatic injuries affects millions of lives each year. Developing in vitro assays that closely recapitulate the physiology of neuromuscular tissues is crucial to understand the formation and maturation of NMJs, as well as to help unravel the mechanisms leading to their degeneration and repair. We present a microfluidic platform designed to coculture myoblast-derived muscle strips and motor neurons differentiated from mouse embryonic stem cells (ESCs) within a three-dimensional (3D) hydrogel. The device geometry mimics the spinal cord-limb physical separation by compartmentalizing the two cell types, which also facilitates the observation of 3D neurite outgrowth and remote muscle innervation. Moreover, the use of compliant pillars as anchors for muscle strips provides a quantitative functional readout of force generation. Finally, photosensitizing the ESC provides a pool of source cells that can be differentiated into optically excitable motor neurons, allowing for spatiodynamic, versatile, and noninvasive in vitro control of the motor units. PMID:27493991

  20. Compartmentation of sucrose during radial transfer in mature sorghum culm

    Directory of Open Access Journals (Sweden)

    Vietor Donald M

    2007-06-01

    Full Text Available Abstract Background The sucrose that accumulates in the culm of sorghum (Sorghum bicolor (L. Moench and other large tropical andropogonoid grasses can be of commercial value, and can buffer assimilate supply during development. Previous study conducted with intact plants showed that sucrose can be radially transferred to the intracellular compartment of mature ripening sorghum internode without being hydrolysed. In this study, culm-infused radiolabelled sucrose was traced between cellular compartments and among related metabolites to determine if the compartmental path of sucrose during radial transfer in culm tissue was symplasmic or included an apoplasmic step. This transfer path was evaluated for elongating and ripening culm tissue of intact plants of two semidwarf grain sorghums. The metabolic path in elongating internode tissue was also evaluated. Results On the day after culm infusion of the tracer sucrose, the specific radioactivity of sucrose recovered from the intracellular compartment of growing axillary-branch tissue was greater (nearly twice than that in the free space, indicating that sucrose was preferentially transferred through symplasmic routes. In contrast, the sucrose specific radioactivity in the intracellular compartment of the mature (ripening culm tissue was probably less (about 3/4's than that in free space indicating that sucrose was preferentially transferred through routes that included an apoplasmic step. In growing internodes of the axillary branch of sorghum, the tritium label initially provided in the fructose moiety of sucrose molecules was largely (81% recovered in the fructose moiety, indicating that a large portion of sucrose molecules is not hydrolysed and resynthesized during radial transfer. Conclusion During radial transfer of sucrose in ripening internodes of intact sorghum plants, much of the sucrose is transferred intact (without hydrolysis and resynthesis and primarily through a path that includes an

  1. The paraveinal mesophyll of soybean leaves in relation to assimilate transfer and compartmentation : II. Structural, metabolic and compartmental changes during reproductive growth.

    Science.gov (United States)

    Franceschi, V R; Giaquinta, R T

    1983-04-01

    Nitrogen and carbohydrate assimilates were temporally and spatially compartmented among various cell types in soybean (Glycine max L., Merr.) leaves during seed filling. The paraveinal mesophyll (PVM), a unique cell layer found in soybean, was demonstrated to function in the synthesis, compartmentation and remobilization of nitrogen reserves prior to and during the seed-filling stages. At anthesis, the PVM vacuoles contain substantial protein which completely disappears by two weeks into the seed filling. Distinct changes in the PVM cytoplasm, tonoplast and organelles were correlated with the presence or absence of the vacuolar material. Microautoradiography following the accumulation of several radiolabeled sugars and amino acids demonstrated the glycoprotein nature of the vacuolar material. Incorporation of methionine, leucine, glucose, and glucosamine resulted in heavy labelling of the PVM vacuole, in contrast to galactose, proline, and mannose which resulted in a much reduced labelling pattern. In addition, starch is unequally compartmented and degraded among the various leaf cells during seed filling. At the end of the photoperiod at the flowering stage, the highest starch accumulation was in the second palisade layer followed by the spongy mesophyll and the first (uppermost) palisade layer. Starch in the first palisade layer was completely degraded during the dark whereas the starch in the second palisade and spongy mesophyll was not remobilized to any appreciable extent. By mid-podfilling (approximately five weeks postanthesis) starch was absent in the first palisade layer at the end of the photoperiod while the second palisade and spongy mesophyll layers contained substantial starch. Starch was remobilized from these latter cells during the remainder of seed filling when current photosynthetic production is low. Structural changes associated with cell senescence first appear in the upper palisade layer and then progress (excluding the PVM) to the second

  2. In or out? On the tightness of glycosomal compartmentalization of metabolites and enzymes in Trypanosoma brucei

    NARCIS (Netherlands)

    Haanstra, Jurgen R.; Bakker, Barbara M.; Michels, Paul A. M.

    2014-01-01

    Trypanosomatids sequester large parts of glucose metabolism inside specialised peroxisomes, called glycosomes. Many studies have shown that correct glycosomal compartmentalization of glycolytic enzymes is essential for bloodstream-form Trypanosoma brucel. The recent finding of pore-forming activitie

  3. Compartmental models for assessing the fishery production in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.; Parulekar, A.H.

    Compartmental models for assessing the fishery production in the Indian Ocean is discussed. The article examines the theoretical basis on which modern fishery sciences is built. The model shows that, large changes in energy flux from one pathway...

  4. A bulk sub-femtoliter in vitro compartmentalization system using super-fine electrosprays.

    Science.gov (United States)

    Sharma, Bineet; Takamura, Yuzuru; Shimoda, Tatsuya; Biyani, Manish

    2016-01-01

    The extreme miniaturization of biological and chemical assays in aqueous-droplet compartments enables spatiotemporal control for large-scale parallel experimentation and can thus permit new capabilities for "digitizing" directed molecular evolution methodologies. We report a remarkably facile bulk method to generate mega-scale monodisperse sub-femtoliter aqueous droplets by electrospray, using a prototype head with super-fine inkjet technology. Moreover, the electrostatic inkjet nozzle that injects the aqueous phase when immersed within an immiscible phase (an optimized oil/surfactant mixture) has the advantage of generating cell-like sub-femtoliter compartments for biomolecule encapsulation and successive biological and chemical reactions. Sub-femtoliter droplets of both liquid (water-in-oil, volumes ranging from 0.2 to 6.4 fL) and gel bead (agarose-in-oil, volume ranging from 0.3 to 15.6 fL) compartments with average sizes of 1.3 μm and 1.5 μm, respectively, were successfully generated using an inkjet nozzle at a speed of more than 10(5) droplets per second. We demonstrated the applicability of this system by synthesizing fluorescent proteins using a cell-free expression system inside electrosprayed sub-femtoliter droplets at an accelerated rate, thereby extending the utility of in vitro compartmentalization with improved analytical performance for a top-down artificial cellular system. PMID:27199080

  5. A clickable neurosteroid photolabel reveals selective Golgi compartmentalization with preferential impact on proximal inhibition.

    Science.gov (United States)

    Jiang, Xiaoping; Shu, Hong-Jin; Krishnan, Kathiresan; Qian, Mingxing; Taylor, Amanda A; Covey, Douglas F; Zorumski, Charles F; Mennerick, Steven

    2016-09-01

    Anesthetic, GABA-active neurosteroids potently augment GABAA receptor function, leading to important behavioral consequences. Neurosteroids and their synthetic analogues are also models for a wide variety of cell-permeant neuroactive compounds. Cell permeation and compartmentalization raise the possibility that these compounds' actions are influenced by their cellular partitioning, but these contributions are not typically considered experimentally or therapeutically. To examine the interplay between cellular accumulation and pharmacodynamics of neurosteroids, we synthesized a novel chemical biology analogue (bio-active, clickable photolabel) of GABA-active neurosteroids. We discovered that the analogue selectively photo-labels neuronal Golgi in rat hippocampal neurons. The active analogue's selective distribution was distinct from endogenous cholesterol and not completely shared by some non-GABA active, neurosteroid-like analogues. On the other hand, the distribution was not enantioselective and did not require energy, in contrast to other recent precedents from the literature. We demonstrate that the soma-selective accumulation can act as a sink or source for steroid actions at plasma-membrane GABA receptors, altering steady-state and time course of effects at somatic GABAA receptors relative to dendritic receptors. Our results suggest a novel mechanism for compartment-selective drug actions at plasma-membrane receptors. PMID:27114255

  6. Dynamin regulates metaphase furrow formation and plasma membrane compartmentalization in the syncytial Drosophila embryo

    Directory of Open Access Journals (Sweden)

    Richa Rikhy

    2015-02-01

    Full Text Available The successive nuclear division cycles in the syncytial Drosophila embryo are accompanied by ingression and regression of plasma membrane furrows, which surround individual nuclei at the embryo periphery, playing a central role in embryo compartmentalization prior to cellularization. Here, we demonstrate that cell cycle changes in dynamin localization and activity at the plasma membrane (PM regulate metaphase furrow formation and PM organization in the syncytial embryo. Dynamin was localized on short PM furrows during interphase, mediating endocytosis of PM components. Dynamin redistributed off ingressed PM furrows in metaphase, correlating with stabilized PM components and the associated actin regulatory machinery on long furrows. Acute inhibition of dynamin in the temperature sensitive shibire mutant embryo resulted in morphogenetic consequences in the syncytial division cycle. These included inhibition of metaphase furrow ingression, randomization of proteins normally polarized to intercap PM and disruption of the diffusion barrier separating PM domains above nuclei. Based on these findings, we propose that cell cycle changes in dynamin orchestrate recruitment of actin regulatory machinery for PM furrow dynamics during the early mitotic cycles in the Drosophila embryo.

  7. Molecular System Bioenergics of the Heart: Experimental Studies of Metabolic Compartmentation and Energy Fluxes versus Computer Modeling

    Directory of Open Access Journals (Sweden)

    Valdur Saks

    2011-12-01

    Full Text Available In this review we analyze the recent important and remarkable advancements in studies of compartmentation of adenine nucleotides in muscle cells due to their binding to macromolecular complexes and cellular structures, which results in non-equilibrium steady state of the creatine kinase reaction. We discuss the problems of measuring the energy fluxes between different cellular compartments and their simulation by using different computer models. Energy flux determinations by 18O transfer method have shown that in heart about 80% of energy is carried out of mitochondrial intermembrane space into cytoplasm by phosphocreatine fluxes generated by mitochondrial creatine kinase from adenosine triphosphate (ATP, produced by ATP Synthasome. We have applied the mathematical model of compartmentalized energy transfer for analysis of experimental data on the dependence of oxygen consumption rate on heart workload in isolated working heart reported by Williamson et al. The analysis of these data show that even at the maximal workloads and respiration rates, equal to 174 µmol O2 per min per g dry weight, phosphocreatine flux, and not ATP, carries about 80–85% percent of energy needed out of mitochondria into the cytosol. We analyze also the reasons of failures of several computer models published in the literature to correctly describe the experimental data.

  8. Efficient Vaccine Distribution Based on a Hybrid Compartmental Model.

    Directory of Open Access Journals (Sweden)

    Zhiwen Yu

    Full Text Available To effectively and efficiently reduce the morbidity and mortality that may be caused by outbreaks of emerging infectious diseases, it is very important for public health agencies to make informed decisions for controlling the spread of the disease. Such decisions must incorporate various kinds of intervention strategies, such as vaccinations, school closures and border restrictions. Recently, researchers have paid increased attention to searching for effective vaccine distribution strategies for reducing the effects of pandemic outbreaks when resources are limited. Most of the existing research work has been focused on how to design an effective age-structured epidemic model and to select a suitable vaccine distribution strategy to prevent the propagation of an infectious virus. Models that evaluate age structure effects are common, but models that additionally evaluate geographical effects are less common. In this paper, we propose a new SEIR (susceptible-exposed-infectious šC recovered model, named the hybrid SEIR-V model (HSEIR-V, which considers not only the dynamics of infection prevalence in several age-specific host populations, but also seeks to characterize the dynamics by which a virus spreads in various geographic districts. Several vaccination strategies such as different kinds of vaccine coverage, different vaccine releasing times and different vaccine deployment methods are incorporated into the HSEIR-V compartmental model. We also design four hybrid vaccination distribution strategies (based on population size, contact pattern matrix, infection rate and infectious risk for controlling the spread of viral infections. Based on data from the 2009-2010 H1N1 influenza epidemic, we evaluate the effectiveness of our proposed HSEIR-V model and study the effects of different types of human behaviour in responding to epidemics.

  9. Distinct PKA and Epac compartmentalization in airway function and plasticity

    NARCIS (Netherlands)

    Dekkers, Bart G. J.; Racke, Kurt; Schmidt, Martina

    2013-01-01

    Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases characterized by airway obstruction, airway inflammation and airway remodelling. Next to inflammatory cells and airway epithelial cells, airway mesenchymal cells, including airway smooth muscle cells and (myo)fibro

  10. Immunometabolism of obesity and diabetes: microbiota link compartmentalized immunity in the gut to metabolic tissue inflammation.

    Science.gov (United States)

    McPhee, Joseph B; Schertzer, Jonathan D

    2015-12-01

    The bacteria that inhabit us have emerged as factors linking immunity and metabolism. Changes in our microbiota can modify obesity and the immune underpinnings of metabolic diseases such as Type 2 diabetes. Obesity coincides with a low-level systemic inflammation, which also manifests within metabolic tissues such as adipose tissue and liver. This metabolic inflammation can promote insulin resistance and dysglycaemia. However, the obesity and metabolic disease-related immune responses that are compartmentalized in the intestinal environment do not necessarily parallel the inflammatory status of metabolic tissues that control blood glucose. In fact, a permissive immune environment in the gut can exacerbate metabolic tissue inflammation. Unravelling these discordant immune responses in different parts of the body and establishing a connection between nutrients, immunity and the microbiota in the gut is a complex challenge. Recent evidence positions the relationship between host gut barrier function, intestinal T cell responses and specific microbes at the crossroads of obesity and inflammation in metabolic disease. A key problem to be addressed is understanding how metabolite, immune or bacterial signals from the gut are relayed and transferred into systemic or metabolic tissue inflammation that can impair insulin action preceding Type 2 diabetes.

  11. Dorsoventral compartmentalization of mesoderm in heart-forming area of chick embryo.

    Science.gov (United States)

    Kärner, M; Krinka, D; Padari, K; Kärner, J; Raid, R

    2000-06-01

    In early chick development (stages 5-8) the seemingly homogeneous mesoderm in the heart-forming area splits to somatic and splanchnic cardiogenic layers. Little is known about dorsoventral compartmentalization before splitting. Electron microscopic analysis shows the early dorsoventral polarization of precardiomyocytes. The dorsal compartment has epithelial and the ventral compartment mesenchymal features with numerous protrusions. At stage 5+-6 staining for wheat germ agglutinine (WGA) transiently demarcates the ventral part of mesoderm. The glycosomes (beta-glycogen) show a dorsoventral gradient in the mesoderm of the cardiogenic field during the initial step of the compaction. The differential expression of glycosomes depends on the activity of glycogen synthase kinase 3-beta, a component of the wnt-signaling pathway, and might in this spatiotemporal developmental window be involved in the commitment of presumptive cardiogenic and somatic cells. To verify this hypothesis simulation experiments with LiCl in vitro were carried out. The normal splitting of the mesoderm and the development of heart primordia were disturbed. Blocking the receptors of WGA by WGA in vitro at stage 5-5+ perturbs the migration of mesoderm to anterio-medial direction. It appears that early specification of dorsal and ventral compartments of the mesoderm in the heart-forming area correlates with the gradient of glycosomes. Our results suggest that the target of LiCl action (glycogen synthase kinase 3-beta) might be involved in the specification of heart primordia and that WGA receptors mediate the migration of mesoderm to the anteriomedial direction.

  12. The subcellular compartmentalization of arginine metabolizing enzymes and their role in endothelial dysfunction

    Directory of Open Access Journals (Sweden)

    Feng eChen

    2013-07-01

    Full Text Available The endothelial production of nitric oxide (NO mediates endothelium-dependent vasorelaxation and restrains vascular inflammation, smooth muscle proliferation and platelet aggregation. Impaired production of NO is a hallmark of endothelial dysfunction and promotes the development of cardiovascular disease. In endothelial cells, NO is generated by endothelial nitric oxide synthase (eNOS through the conversion of its substrate, L-arginine to L-citrulline. Reduced access to L-arginine has been proposed as a major mechanism underlying reduced eNOS activity and NO production in cardiovascular disease. The arginases (Arg1 and Arg2 metabolize L-arginine to generate L-ornithine and urea and increased expression of arginase has been proposed as a mechanism of reduced eNOS activity secondary to the depletion of L-arginine. Indeed, supplemental L-arginine and suppression of arginase activity has been shown to improve endothelium-dependent relaxation and ameliorate cardiovascular disease. However, L-arginine concentrations in endothelial cells remain sufficiently high to support NO synthesis suggesting additional mechanisms. The compartmentalization of intracellular L-arginine into poorly interchangeable pools has been proposed to allow for the local depletion of L-arginine. Indeed the subcellular location of L-arginine metabolizing enzymes plays important functional roles. In endothelial cells, eNOS is found in discrete intracellular locations and the capacity to generate NO is heavily influenced by its localtion. Arg1 and Arg2 also reside in different subcellular environments and are thought to differentially influence endothelial function. The plasma membrane solute transporter, CAT-1 and the arginine recycling enzyme, ASL, co-localize with eNOS and facilitate NO release. This review highlights the importance of the subcellular location of eNOS and arginine transporting and metabolizing enzymes to NO release and cardiovascular disease.

  13. Distribution and compartmental organization of GABAergic medium-sized spiny neurons in the mouse Nucleus Accumbens

    Directory of Open Access Journals (Sweden)

    Giuseppe eGangarossa

    2013-02-01

    Full Text Available The nucleus accumbens (NAc is a critical brain region involved in many reward-related behaviors. The NAc comprises major compartments the core and the shell, which encompass several subterritories. GABAergic medium-sized spiny neurons (MSNs constitute the output neurons of the NAc core and shell. While the functional organization of the NAc core outputs resembles the one described for the dorsal striatum, a simple classification of the NAc shell neurons has been difficult to define due to the complexity of the compartmental segregation of cells. We used a variety of BAC transgenic mice expressing enhanced green fluorescence (EGFP or the Cre-recombinase (Cre under the control of the promoter of dopamine D1, D2, and D3 receptors and of adenosine A2a receptor to dissect the microanatomy of the NAc. Moreover, using various immunological markers we characterized in detail the distribution of MSNs in the mouse NAc. In addition, cell-type specific ERK phosphorylation in the NAc subterritories was analyzed following acute administration of SKF81297 (a D1R-like agonist, quinpirole (a D2R-like agonist, apomorphine (a non-selective DA receptor agonist, raclopride (a D2R-like antagonist, and psychostimulant drugs, including cocaine and d-amphetamine. Each drug generated a unique topography and cell-type specific activation of ERK in the NAc. Our results show the existence of marked differences in the receptor expression pattern and functional activation of MSNs within the shell subterritories. This study emphasizes the anatomical and functional heterogeneity of the NAc, which will have to be considered in its further study.

  14. Heterogeneity and compartmental properties of insulin storage and secretion in rat islets

    Energy Technology Data Exchange (ETDEWEB)

    Gold, G.; Landahl, H.D.; Gishizky, M.L.; Grodsky, G.M.

    1982-03-01

    To investigate compartmental properties of insulin storage and secretion, isolated rat islets were used for pulse-labeling experiments, after which proinsulin and insulin were purified rigorously. Processing of proinsulin to insulin neared completion by 3 h without additional loss of either radioactive peptide by cellular or extracellular proteolysis. The amount of labeled hormone rapidly diminished in islets; it was secreted at a higher fractional rate than immunoreactive insulin, resulting in secreted insulin's having a higher specific activity than the average cellular insulin. Newly synthesized insulin, therefore, was secreted preferentially. Changes in the specific activity of secreted and cellular insulin with time were consistent with changes predicted for islets containing 33% of their total insulin in a glucose-labile compartment. Predictions were based on steady-state analysis of a simple storage-limited representation of B cell function. Islets from either the dorsal or ventral part of the pancreas also contained 33% of their total insulin in a glucose-labile compartment. The same compartment was mobilized by 20 mM glucose, 50 mM potassium + 2 mM glucose, or 20 MM glucose + 1 mM 3-isobutylmethylxanthine as indicated by the specific activity ratio of secreted vs. cellular insulin, even though average secretion rates with these stimuli differed by more than threefold. In the absence of calcium, the effectiveness of 20 mM glucose as a secretagogue declined markedly, and the older stored insulin was preferentially mobilized because secreted insulin had a lower rather than a higher specific activity than cellular insulin. Results provide insight into the mechanisms of nonrandom mobilization and secretion of insulin form the B cell.

  15. Heterogeneity and compartmental properties of insulin storage and secretion in rat islets

    International Nuclear Information System (INIS)

    To investigate compartmental properties of insulin storage and secretion, isolated rat islets were used for pulse-labeling experiments, after which proinsulin and insulin were purified rigorously. Processing of proinsulin to insulin neared completion by 3 h without additional loss of either radioactive peptide by cellular or extracellular proteolysis. The amount of labeled hormone rapidly diminished in islets; it was secreted at a higher fractional rate than immunoreactive insulin, resulting in secreted insulin's having a higher specific activity than the average cellular insulin. Newly synthesized insulin, therefore, was secreted preferentially. Changes in the specific activity of secreted and cellular insulin with time were consistent with changes predicted for islets containing 33% of their total insulin in a glucose-labile compartment. Predictions were based on steady-state analysis of a simple storage-limited representation of B cell function. Islets from either the dorsal or ventral part of the pancreas also contained 33% of their total insulin in a glucose-labile compartment. The same compartment was mobilized by 20 mM glucose, 50 mM potassium + 2 mM glucose, or 20 MM glucose + 1 mM 3-isobutylmethylxanthine as indicated by the specific activity ratio of secreted vs. cellular insulin, even though average secretion rates with these stimuli differed by more than threefold. In the absence of calcium, the effectiveness of 20 mM glucose as a secretagogue declined markedly, and the older stored insulin was preferentially mobilized because secreted insulin had a lower rather than a higher specific activity than cellular insulin. Results provide insight into the mechanisms of nonrandom mobilization and secretion of insulin form the B cell

  16. Compartmental analysis of dynamic nuclear medicine data: regularization procedure and application to physiology

    CERN Document Server

    Fabrice, Delbary

    2016-01-01

    Compartmental models based on tracer mass balance are extensively used in clinical and pre-clinical nuclear medicine in order to obtain quantitative information on tracer metabolism in the biological tissue. This paper is the second of a series of two that deal with the problem of tracer coefficient estimation via compartmental modelling in an inverse problem framework. While the previous work was devoted to the discussion of identifiability issues for 2, 3 and n-dimension compartmental systems, here we discuss the problem of numerically determining the tracer coefficients by means of a general regularized Multivariate Gauss Newton scheme. In this paper, applications concerning cerebral, hepatic and renal functions are considered, involving experimental measurements on FDG-PET data on different set of murine models.

  17. A Computational Modeling and Simulation Approach to Investigate Mechanisms of Subcellular cAMP Compartmentation.

    Directory of Open Access Journals (Sweden)

    Pei-Chi Yang

    2016-07-01

    Full Text Available Subcellular compartmentation of the ubiquitous second messenger cAMP has been widely proposed as a mechanism to explain unique receptor-dependent functional responses. How exactly compartmentation is achieved, however, has remained a mystery for more than 40 years. In this study, we developed computational and mathematical models to represent a subcellular sarcomeric space in a cardiac myocyte with varying detail. We then used these models to predict the contributions of various mechanisms that establish subcellular cAMP microdomains. We used the models to test the hypothesis that phosphodiesterases act as functional barriers to diffusion, creating discrete cAMP signaling domains. We also used the models to predict the effect of a range of experimentally measured diffusion rates on cAMP compartmentation. Finally, we modeled the anatomical structures in a cardiac myocyte diad, to predict the effects of anatomical diffusion barriers on cAMP compartmentation. When we incorporated experimentally informed model parameters to reconstruct an in silico subcellular sarcomeric space with spatially distinct cAMP production sites linked to caveloar domains, the models predict that under realistic conditions phosphodiesterases alone were insufficient to generate significant cAMP gradients. This prediction persisted even when combined with slow cAMP diffusion. When we additionally considered the effects of anatomic barriers to diffusion that are expected in the cardiac myocyte dyadic space, cAMP compartmentation did occur, but only when diffusion was slow. Our model simulations suggest that additional mechanisms likely contribute to cAMP gradients occurring in submicroscopic domains. The difference between the physiological and pathological effects resulting from the production of cAMP may be a function of appropriate compartmentation of cAMP signaling. Therefore, understanding the contribution of factors that are responsible for coordinating the spatial and

  18. A Computational Modeling and Simulation Approach to Investigate Mechanisms of Subcellular cAMP Compartmentation.

    Science.gov (United States)

    Yang, Pei-Chi; Boras, Britton W; Jeng, Mao-Tsuen; Docken, Steffen S; Lewis, Timothy J; McCulloch, Andrew D; Harvey, Robert D; Clancy, Colleen E

    2016-07-01

    Subcellular compartmentation of the ubiquitous second messenger cAMP has been widely proposed as a mechanism to explain unique receptor-dependent functional responses. How exactly compartmentation is achieved, however, has remained a mystery for more than 40 years. In this study, we developed computational and mathematical models to represent a subcellular sarcomeric space in a cardiac myocyte with varying detail. We then used these models to predict the contributions of various mechanisms that establish subcellular cAMP microdomains. We used the models to test the hypothesis that phosphodiesterases act as functional barriers to diffusion, creating discrete cAMP signaling domains. We also used the models to predict the effect of a range of experimentally measured diffusion rates on cAMP compartmentation. Finally, we modeled the anatomical structures in a cardiac myocyte diad, to predict the effects of anatomical diffusion barriers on cAMP compartmentation. When we incorporated experimentally informed model parameters to reconstruct an in silico subcellular sarcomeric space with spatially distinct cAMP production sites linked to caveloar domains, the models predict that under realistic conditions phosphodiesterases alone were insufficient to generate significant cAMP gradients. This prediction persisted even when combined with slow cAMP diffusion. When we additionally considered the effects of anatomic barriers to diffusion that are expected in the cardiac myocyte dyadic space, cAMP compartmentation did occur, but only when diffusion was slow. Our model simulations suggest that additional mechanisms likely contribute to cAMP gradients occurring in submicroscopic domains. The difference between the physiological and pathological effects resulting from the production of cAMP may be a function of appropriate compartmentation of cAMP signaling. Therefore, understanding the contribution of factors that are responsible for coordinating the spatial and temporal

  19. Subcellular compartmentation of sugar signalling: Links among carbon cellular status, route of sucrolysis, sink-source allocation, and metabolic partitioning

    Directory of Open Access Journals (Sweden)

    Axel eTiessen

    2013-01-01

    Full Text Available Recent findings suggest that both subcellular compartmentation and route of sucrolysis are important for plant development, growth, and yield. Signalling effects are dependent on the tissue, cell type and stage of development. Downstream effects also depend on the amount and localisation of hexoses and disaccharides. All enzymes of sucrose metabolism (e.g. invertase, hexokinase, fructokinase, sucrose synthase, and sucrose 6-phosphate synthase are not produced from single genes, but from paralogue families in plant genomes. Each paralogue has unique expression across plant organs and developmental stages. Multiple isoforms can be targeted to different cellular compartments (e.g. plastids, mitochondria, nuclei, and cytosol. Many of the key enzymes are regulated by post-transcriptional modifications and associate in multimeric protein complexes. Some isoforms have regulatory functions, either in addition to or in replacement of their catalytic activity. This explains why some isozymes are not redundant, but also complicates elucidation of their specific involvement in sugar signalling. The subcellular compartmentation of sucrose metabolism forces refinement of some of the paradigms of sugar signalling during physiological processes. For example, the catalytic and signalling functions of diverse paralogues needs to be more carefully analysed in the context of post-genomic biology. It is important to note that it is the differential localization of both the sugars themselves as well as the sugar-metabolizing enzymes that ultimately led to sugar signalling. We conclude that a combination of subcellular complexity and gene duplication/subfunctionalization gave rise to sugar signalling as a regulatory mechanism in plant cells.

  20. Branching patterns of olivocerebellar axons in relation to the compartmental organization of the cerebellum

    Directory of Open Access Journals (Sweden)

    Hirofumi eFujita

    2013-02-01

    Full Text Available A single olivocerebellar (OC axon gives rise to about seven branches that terminate as climbing fibers (CFs. Branching patterns of an OC axon, which are classified into local, transverse and longitudinal types, are highly organized, in relation to the longitudinal molecular (aldolase C or zebrin II compartmentalization and the transverse lobulation of the cerebellum. Local branching is involved in forming a narrow band-shaped functional subarea within a molecular compartment. On the other hand, transverse and longitudinal branchings appear to be involved in linking mediolaterally separated molecular compartments and rostrocaudally separated lobular areas, respectively. Longitudinal branching occurs frequently between equivalent molecular compartments of specific combinations of lobules. These combinations include lobule V-simple lobule and crus II-paramedian lobule in the pars intermedia and hemisphere, and lobules I-V and lobule VIII in the vermis. The longitudinal branching pattern not only fits with mirror-imaged somatosensory double representation of the body in the pars intermedia, but it also suggests a general rostrocaudal link exists for the whole cerebellum across the putative rostrocaudal boundary in lobule VIc-crus I. Molecular compartments of the cerebellar cortex originate from the Purkinje cell (PC clusters that appear in the late embryonic stage, when the immature OC projection is formed. Some clusters split rostrocaudally across crus I during the development of cortical compartments, which would result in longitudinal branching of OC projection across crus I. Supposing that the branching pattern of OC axons represents an essential organization of the cerebellum, longitudinal branching suggests a functional and developmental links between the rostral and caudal cerebellum across lobule VIc-crus I throughout the cerebellar cortex.

  1. Krebs cycle metabolon formation: metabolite concentration gradient enhanced compartmentation of sequential enzymes.

    Science.gov (United States)

    Wu, Fei; Pelster, Lindsey N; Minteer, Shelley D

    2015-01-25

    Dynamics of metabolon formation in mitochondria was probed by studying diffusional motion of two sequential Krebs cycle enzymes in a microfluidic channel. Enhanced directional co-diffusion of both enzymes against a substrate concentration gradient was observed in the presence of intermediate generation. This reveals a metabolite directed compartmentation of metabolic pathways.

  2. Structural identifiability from input-output observations of linear compartmental systems

    NARCIS (Netherlands)

    Hof, J.M. van den

    1995-01-01

    In biology and mathematics compartmental systems are frequently used. System identification of systems based on physical laws often involves parameter estimation. Before parameter estimation can take place, we have to examine whether the parameters are structurally identifiable. In this paper tests

  3. Compartmental analysis of renal physiology using nuclear medicine data and statistical optimization

    CERN Document Server

    Garbarino, Sara; Brignone, Massimo; Massollo, Michela; Sambuceti, Gianmario; Piana, Michele

    2012-01-01

    This paper describes a general approach to the compartmental modeling of nuclear data based on spectral analysis and statistical optimization. We utilize the renal physiology as test case and validate the method against both synthetic data and real measurements acquired during two micro-PET experiments with murine models.

  4. The paraveinal mesophyll of soybean leaves in relation to assimilate transfer and compartmentation : I. Ultrastructure and histochemistry during vegetative development.

    Science.gov (United States)

    Franceschi, V R; Giaquinta, R T

    1983-04-01

    The paraveinal mesophyll (PVM) is a unique and specialized, one-cell-thick tissue spanning the vascular bundles at the level of the phloem in soybean (Glycine max) (L.) Merr.) leaves. Its position within the leaf dictates that all photosynthate produced in the palisade and spongy mesophyll must pass through this specialized layer enroute to the phloem. Symplastic continuity, via plasmodesmata, exists between the PVM and bundle sheath, palisade parenchyma and spongy mesophyll. During leaf ontogeny the PVM is the first tissue to differentiate and at maturity these cells are six to eight times larger than other mesophyll cells, are highly vacuolate, and are interconnected by tubular arms. The PVM undergoes several unique structural and metabolic modifications during leaf development. The PVM cytoplasm, in vegetative plants, is dense, enriched in rough endoplasmic reticulum and dictyosomes, but contains few, small starch-free chloroplasts and few microbodies. Unlike the tonoplast of mesophyll cells, the tonoplast of the PVM is unusually thick and dense-staining. During leaf development the vacuoles of PVM cells accumulate a glycoprotein derived from the dictyosomes which reacts with the protein staining reagents, mercuric bromophenol blue and sulfaflavine, and is degraded by Pronase. Both the vacuolar material and tonoplast are also stained by phosphotungstic acid, which at low pH is relatively selective for glycoprotein. A unique role of the PVM in the transport and compartmentation of nitrogen reserves in soybeans is discussed.

  5. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, Eva [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France); Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse (France); Dappe, Vincent [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Sarret, Géraldine [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Sobanska, Sophie [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna [Department of Chemistry, John Paul II Catholic University of Lublin, Al. Kraśnicka 102, 20-718 Lublin (Poland); Magnin, Valérie [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Ranieri, Vincent [CEA-INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Dumat, Camille, E-mail: camille.dumat@ensat.fr [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France)

    2014-04-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO{sub 4}, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO{sub 3}. In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to

  6. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    International Nuclear Information System (INIS)

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess

  7. A development-based compartmentalization of the Drosophila central brain

    OpenAIRE

    Pereanu, Wayne; Kumar, Abilasha; Jennett, Arnim; Reichert, Heinrich; Hartenstein, Volker

    2010-01-01

    The neuropile of the Drosophila brain is subdivided into anatomically discrete compartments. Compartments are rich in terminal neurite branching and synapses; they are the neuropile domains in which signal processing takes place. Compartment boundaries are defined by more or less dense layers of glial cells, as well as long neurite fascicles. These fascicles are formed during the larval period when the approximately 100 neuronal lineages that constitute the Drosophila central brain differenti...

  8. Use of a simulated annealing algorithm to fit compartmental models with an application to fractal pharmacokinetics.

    Science.gov (United States)

    Marsh, Rebeccah E; Riauka, Terence A; McQuarrie, Steve A

    2007-01-01

    Increasingly, fractals are being incorporated into pharmacokinetic models to describe transport and chemical kinetic processes occurring in confined and heterogeneous spaces. However, fractal compartmental models lead to differential equations with power-law time-dependent kinetic rate coefficients that currently are not accommodated by common commercial software programs. This paper describes a parameter optimization method for fitting individual pharmacokinetic curves based on a simulated annealing (SA) algorithm, which always converged towards the global minimum and was independent of the initial parameter values and parameter bounds. In a comparison using a classical compartmental model, similar fits by the Gauss-Newton and Nelder-Mead simplex algorithms required stringent initial estimates and ranges for the model parameters. The SA algorithm is ideal for fitting a wide variety of pharmacokinetic models to clinical data, especially those for which there is weak prior knowledge of the parameter values, such as the fractal models. PMID:17706176

  9. Structurally controlled and aligned tight gas reservoir compartmentalization in the San Juan and Piceance Basins

    Energy Technology Data Exchange (ETDEWEB)

    Decker, A.D.; Kuuskraa, V.A.; Klawitter, A.L.

    1995-10-01

    Recurrent basement faulting is the primary controlling mechanism for aligning and compartmentalizing upper Cretaceous aged tight gas reservoirs of the San Juan and Piceance Basins. Northwest trending structural lineaments that formed in conjunction with the Uncompahgre Highlands have profoundly influenced sedimentation trends and created boundaries for gas migration; sealing and compartmentalizing sedimentary packages in both basins. Fractures which formed over the structural lineaments provide permeability pathways which allowing gas recovery from otherwise tight gas reservoirs. Structural alignments and associated reservoir compartments have been accurately targeted by integrating advanced remote sensing imagery, high resolution aeromagnetics, seismic interpretation, stratigraphic mapping and dynamic structural modelling. This unifying methodology is a powerful tool for exploration geologists and is also a systematic approach to tight gas resource assessment in frontier basins.

  10. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    Directory of Open Access Journals (Sweden)

    Marko Kreft

    2012-04-01

    Full Text Available Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation.

  11. Influence of nonequilibrium lipid transport, membrane compartmentalization, and membrane proteins on the lateral organization of the plasma membrane

    Science.gov (United States)

    Fan, Jun; Sammalkorpi, Maria; Haataja, Mikko

    2010-01-01

    Compositional lipid domains (lipid rafts) in plasma membranes are believed to be important components of many cellular processes. The mechanisms by which cells regulate the sizes, lifetimes, and spatial localization of these domains are rather poorly understood at the moment. We propose a robust mechanism for the formation of finite-sized lipid raft domains in plasma membranes, the competition between phase separation in an immiscible lipid system and active cellular lipid transport processes naturally leads to the formation of such domains. Simulations of a continuum model reveal that the raft size distribution is broad and the average raft size is strongly dependent on the rates of cellular and interlayer lipid transport processes. We demonstrate that spatiotemporal variations in the recycling may enable the cell to localize larger raft aggregates at specific parts along the membrane. Moreover, we show that membrane compartmentalization may further facilitate spatial localization of the raft domains. Finally, we demonstrate that local interactions with immobile membrane proteins can spatially localize the rafts and lead to further clustering.

  12. An in vitro compartmentalization-based method for the selection of bond-forming enzymes from large libraries.

    Science.gov (United States)

    Gianella, Paul; Snapp, Erik L; Levy, Matthew

    2016-08-01

    We have developed a generalized in vitro compartmentalization-based bead display selection strategy that allows for the identification of enzymes that can perform ligation reactions. Although a number of methods have been developed to evolve such enzymes, many of them are limited in library size (10(6) -10(7) ), do not select for enzymes using a scheme that allows for multiple turnover, or only work on enzymes specific to nucleic acids. This approach is amenable to screening libraries of up to 10(12) protein variants by allowing beads to be overloaded with up to 10(4) unique mutants. Using this approach we isolated a variant of sortase A from Staphylococcus aureus that shows a 114-fold enhancement in kcat /KM in the absence of calcium compared to the wild-type and improved resistance to the inhibitory effects of cell lysates. Unlike the wild-type protein, the newly selected variant shows intracellular activity in the cytoplasm of eukaryotic cells where it may prove useful for intracellular labeling or synthetic biological applications. Biotechnol. Bioeng. 2016;113: 1647-1657. © 2016 Wiley Periodicals, Inc. PMID:26806853

  13. Compartmentalized gene regulatory network of the pathogenic fungus Fusarium graminearum.

    Science.gov (United States)

    Guo, Li; Zhao, Guoyi; Xu, Jin-Rong; Kistler, H Corby; Gao, Lixin; Ma, Li-Jun

    2016-07-01

    Head blight caused by Fusarium graminearum threatens world-wide wheat production, resulting in both yield loss and mycotoxin contamination. We reconstructed the global F. graminearum gene regulatory network (GRN) from a large collection of transcriptomic data using Bayesian network inference, a machine-learning algorithm. This GRN reveals connectivity between key regulators and their target genes. Focusing on key regulators, this network contains eight distinct but interwoven modules. Enriched for unique functions, such as cell cycle, DNA replication, transcription, translation and stress responses, each module exhibits distinct expression profiles. Evolutionarily, the F. graminearum genome can be divided into core regions shared with closely related species and variable regions harboring genes that are unique to F. graminearum and perform species-specific functions. Interestingly, the inferred top regulators regulate genes that are significantly enriched from the same genomic regions (P control strategies involving the targeting of master regulators in pathogens. The program can be used to construct GRNs of other plant pathogens. PMID:26990214

  14. Compartmentalization of hepatitis B virus: Looking beyond the liver

    Institute of Scientific and Technical Information of China (English)

    Sibnarayan; Datta

    2015-01-01

    Hepatitis B virus(HBV) is classically considered to be hepatotropic, but accumulating evidences strongly support its extra-hepatotropic nature too. HBV nucleicacids and proteins have long been reported in a variety of extra-hepatic tissues. Of these, HBV has been studied in details in the peripheral blood mononuclear cells(PBMCs), due to its accessibility. From these studies, it is now well established that PBMCs are permissive to HBV infection, replication, transcription and production of infective virions. Furthermore, molecular evolutionary studies have provided definite evidences towards evolution of HBV genome in PBMCs, which is independent of evolution occurring in the liver, leading to the emergence and selection of compartment specific escape variants or drug resistant strains. These variants/resistant strains of HBV remain restricted within the PBMCs and are rarely detected in the serum/plasma. In addition, HBV infected PBMCs have been reported to be directly transmitted through intrauterine modes, and this infection does not correlate significantly with serum HBV surface antigen or HBV DNA markers. This editorial briefly reviews the current knowledge on this topic, emphasizes and delineates the gaps that are required to be filled to properly understand the biological and clinical relevance of extrahepatic tropism of HBV.

  15. Assessing compartmentalized flux in lipid metabolism with isotopes.

    Science.gov (United States)

    Allen, Doug K

    2016-09-01

    Metabolism in plants takes place across multiple cell types and within distinct organelles. The distributions equate to spatial heterogeneity; though the limited means to experimentally assess metabolism frequently involve homogenizing tissues and mixing metabolites from different locations. Most current isotope investigations of metabolism therefore lack the ability to resolve spatially distinct events. Recognition of this limitation has resulted in inspired efforts to advance metabolic flux analysis and isotopic labeling techniques. Though a number of these efforts have been applied to studies in central metabolism; recent advances in instrumentation and techniques present an untapped opportunity to make similar progress in lipid metabolism where the use of stable isotopes has been more limited. These efforts will benefit from sophisticated radiolabeling reports that continue to enrich our knowledge on lipid biosynthetic pathways and provide some direction for stable isotope experimental design and extension of MFA. Evidence for this assertion is presented through the review of several elegant stable isotope studies and by taking stock of what has been learned from radioisotope investigations when spatial aspects of metabolism were considered. The studies emphasize that glycerolipid production occurs across several locations with assembly of lipids in the ER or plastid, fatty acid biosynthesis occurring in the plastid, and the generation of acetyl-CoA and glycerol-3-phosphate taking place at multiple sites. Considering metabolism in this context underscores the cellular and subcellular organization that is important to enhanced production of glycerolipids in plants. An attempt is made to unify salient features from a number of reports into a diagrammatic model of lipid metabolism and propose where stable isotope labeling experiments and further flux analysis may help address questions in the field. This article is part of a Special Issue entitled: Plant Lipid

  16. Assessing compartmentalized flux in lipid metabolism with isotopes.

    Science.gov (United States)

    Allen, Doug K

    2016-09-01

    Metabolism in plants takes place across multiple cell types and within distinct organelles. The distributions equate to spatial heterogeneity; though the limited means to experimentally assess metabolism frequently involve homogenizing tissues and mixing metabolites from different locations. Most current isotope investigations of metabolism therefore lack the ability to resolve spatially distinct events. Recognition of this limitation has resulted in inspired efforts to advance metabolic flux analysis and isotopic labeling techniques. Though a number of these efforts have been applied to studies in central metabolism; recent advances in instrumentation and techniques present an untapped opportunity to make similar progress in lipid metabolism where the use of stable isotopes has been more limited. These efforts will benefit from sophisticated radiolabeling reports that continue to enrich our knowledge on lipid biosynthetic pathways and provide some direction for stable isotope experimental design and extension of MFA. Evidence for this assertion is presented through the review of several elegant stable isotope studies and by taking stock of what has been learned from radioisotope investigations when spatial aspects of metabolism were considered. The studies emphasize that glycerolipid production occurs across several locations with assembly of lipids in the ER or plastid, fatty acid biosynthesis occurring in the plastid, and the generation of acetyl-CoA and glycerol-3-phosphate taking place at multiple sites. Considering metabolism in this context underscores the cellular and subcellular organization that is important to enhanced production of glycerolipids in plants. An attempt is made to unify salient features from a number of reports into a diagrammatic model of lipid metabolism and propose where stable isotope labeling experiments and further flux analysis may help address questions in the field. This article is part of a Special Issue entitled: Plant Lipid

  17. Metabolic hormones, apolipoproteins, adipokines, and cytokines in the alveolar lining fluid of healthy adults: compartmentalization and physiological correlates.

    Directory of Open Access Journals (Sweden)

    Carlos O Mendivil

    Full Text Available Our current understanding of hormone regulation in lung parenchyma is quite limited. We aimed to quantify a diverse array of biologically relevant protein mediators in alveolar lining fluid (ALF, compared to serum concentrations, and explore factors associated with protein compartmentalization on either side of the air-blood barrier.Participants were 24 healthy adult non-smoker volunteers without respiratory symptoms or significant medical conditions, with normal lung exams and office spirometry. Cell-free bronchoalveolar lavage fluid and serum were analyzed for 24 proteins (including enteric and metabolic hormones, apolipoproteins, adipokines, and cytokines using a highly sensitive multiplex ELISA. Measurements were normalized to ALF concentrations. The ALF:serum concentration ratios were examined in relation to measures of protein size, hydrophobicity, charge, and to participant clinical and spirometric values.ALF measurements from 24 individuals detected 19 proteins, including adiponectin, adipsin, apoA-I, apoA-II, apoB, apoC-II, apoC-III, apoE, C-reactive protein, ghrelin, glucose-dependent insulinotropic peptide (GIP, glucagon-like peptide-1 (GLP-1, glucagon, insulin, leptin, monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, resistin, and visfatin. C-peptide and serpin E1 were not detected in ALF for any individual, and IL-6, IL-10, and TNF-alpha were not detected in either ALF or serum for any individual. In general, ALF levels were similar or lower in concentration for most proteins compared to serum. However, ghrelin, resistin, insulin, visfatin and GLP-1 had ALF concentrations significantly higher compared to serum. Importantly, elevated ALF:serum ratios of ghrelin, visfatin and resistin correlated with protein net charge and isoelectric point, but not with molecular weight or hydrophobicity.Biologically relevant enteric and metabolic hormones, apolipoproteins, adipokines, and cytokines can be detected in the ALF of

  18. Simultaneous compartmentalization of lead and arsenic in co-hyperaccumulator Viola principis H. de Boiss.: an application of SRXRF microprobe.

    Science.gov (United States)

    Lei, Mei; Chen, Tong-Bin; Huang, Ze-Chun; Wang, Yao-Dong; Huang, Yu-Ying

    2008-08-01

    The cellular distributions of Pb and As in the leaves of co-hyperaccumulator Viola principis H. de Boiss. were inspected by synchrotron X-ray fluorescence spectroscopy (SRXRF). The results revealed that Pb and As had similar compartmentalization patterns in the leaves. Both elements were enriched in the bundle sheath and the palisade mesophyll. In comparison with the sheath and the mesophyll, the vascular bundle and the epidermis contained lower levels of Pb and As. The palisade enrichment of Pb and As indicated that V. principis H. de Boiss. may have a special mechanism on detoxification of toxic metals within the mesophyll cells. Relative concentrations of both Pb and As in trichome bases were higher than those in trichome rays. The results of hierarchical cluster analysis and correlation analysis confirmed that the distribution of Pb was similar to that of As in the leaves, and their distribution patterns were different from the nutrient elements, such as K, Ca, Mn, Fe, Ni, Cu and Zn. In vivo cellular localization of Pb and As in the leaves provides insight into the physiological mechanisms of metal tolerance and hyperaccumulation in the hyperaccumulators.

  19. Estimate of FDG excretion by means of compartmental analysis and ant colony optimization of nuclear medicine data.

    Science.gov (United States)

    Garbarino, Sara; Caviglia, Giacomo; Brignone, Massimo; Massollo, Michela; Sambuceti, Gianmario; Piana, Michele

    2013-01-01

    [(18)F]fluoro-2-deoxy-D-glucose (FDG) is one of the most utilized tracers for positron emission tomography (PET) applications in oncology. FDG-PET relies on higher glycolytic activity in tumors compared to normal structures as the basis of image contrast. As a glucose analog, FDG is transported into malignant cells which typically exhibit an increased radioactivity. However, different from glucose, FDG is not reabsorbed by the renal system and is excreted to the bladder. The present paper describes a novel computational method for the quantitative assessment of this excretion process. The method is based on a compartmental analysis of FDG-PET data in which the excretion process is explicitly accounted for by the bladder compartment and on the application of an ant colony optimization (ACO) algorithm for the determination of the tracer coefficients describing the FDG transport effectiveness. The validation of this approach is performed by means of both synthetic data and real measurements acquired by a PET device for small animals (micro-PET). Possible oncological applications of the results are discussed in the final section. PMID:24191175

  20. Development of an in vitro compartmentalization screen for high-throughput directed evolution of [FeFe] hydrogenases.

    Directory of Open Access Journals (Sweden)

    James A Stapleton

    Full Text Available BACKGROUND: [FeFe] hydrogenase enzymes catalyze the formation and dissociation of molecular hydrogen with the help of a complex prosthetic group composed of common elements. The development of energy conversion technologies based on these renewable catalysts has been hindered by their extreme oxygen sensitivity. Attempts to improve the enzymes by directed evolution have failed for want of a screening platform capable of throughputs high enough to adequately sample heavily mutated DNA libraries. In vitro compartmentalization (IVC is a powerful method capable of screening for multiple-turnover enzymatic activity at very high throughputs. Recent advances have allowed [FeFe] hydrogenases to be expressed and activated in the cell-free protein synthesis reactions on which IVC is based; however, IVC is a demanding technique with which many enzymes have proven incompatible. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe an extremely high-throughput IVC screen for oxygen-tolerant [FeFe] hydrogenases. We demonstrate that the [FeFe] hydrogenase CpI can be expressed and activated within emulsion droplets, and identify a fluorogenic substrate that links activity after oxygen exposure to the generation of a fluorescent signal. We present a screening protocol in which attachment of mutant genes and the proteins they encode to the surfaces of microbeads is followed by three separate emulsion steps for amplification, expression, and evaluation of hydrogenase mutants. We show that beads displaying active hydrogenase can be isolated by fluorescence-activated cell-sorting, and we use the method to enrich such beads from a mock library. CONCLUSIONS/SIGNIFICANCE: [FeFe] hydrogenases are the most complex enzymes to be produced by cell-free protein synthesis, and the most challenging targets to which IVC has yet been applied. The technique described here is an enabling step towards the development of biocatalysts for a biological hydrogen economy.

  1. Photosynthetic Characteristics of Portulaca grandiflora, a Succulent C(4) Dicot : CELLULAR COMPARTMENTATION OF ENZYMES AND ACID METABOLISM.

    Science.gov (United States)

    Ku, S B; Shieh, Y J; Reger, B J; Black, C C

    1981-11-01

    The succulent, cylindrical leaves of the C(4) dicot Portulaca grandiflora possess three distinct green cell types: bundle sheath cells (BSC) in radial arrangement around the vascular bundles; mesophyll cells (MC) in an outer layer adjacent to the BSC; and water storage cells (WSC) in the leaf center. Unlike typical Kranz leaf anatomy, the MC do not surround the bundle sheath tissue but occur only in the area between the bundle sheath and the epidermis. Intercellular localization of photosynthetic enzymes was characterized using protoplasts isolated enzymatically from all three green cell types.Like other C(4) plants, P. grandiflora has ribulose 1,5-bisphosphate carboxylase and the decarboxylating enzyme, NADP(+)-malic enzyme, in the BSC. Unlike other C(4) plants, however, phosphoenolpyruvate carboxylase, pyruvate, Pi dikinase, and NADP(+)-malate dehydrogenase of the C(4) pathway were present in all three green cell types, indicating that all are capable of fixing CO(2) via phosphoenolpyruvate carboxylase and regenerating phosphoenolpyruvate. Other enzymes were about equally distributed between MC and BSC similar to other C(4) plants. The enzyme profile of the WSC was similar to that of the MC but with reduced activity in most enzymes, except mitochondrion-associated enzymes.Intracellular localization of enzymes was studied in organelles partitioned by differential centrifugation using mechanically ruptured mesophyll and bundle sheath protoplasts. Phosphoenolpyruvate carboxylase was a cytosolic enzyme in both cells; whereas, ribulose 1,5-bisphosphate carboxylase and NADP(+)-malic enzyme were exclusively compartmentalized in the bundle sheath chloroplasts. NADP(+)-malate dehydrogenase, pyruvate, Pi dikinase, aspartate aminotransferase, 3-phosphoglycerate kinase, and NADP(+)-triose-P dehydrogenase were predominantly localized in the chloroplasts while alanine aminotransferase and NAD(+)-malate dehydrogenase were mainly present in the cytosol of both cell types. Based

  2. Compartmentalized self-replication: a novel method for the directed evolution of polymerases and other enzymes.

    Science.gov (United States)

    Ghadessy, Farid J; Holliger, Philipp

    2007-01-01

    Compartmentalized self-replication (CSR) is a novel method for the directed evolution of enzymes and, in particular, polymerases. In its simplest form, CSR consists of a simple feedback loop involving a polymerase that replicates only its own encoding gene (self-replication). Self-replication occurs in discrete, spatially separate, noncommunicating compartments formed by a heat-stable water-in-oil emulsion. Compartmentalization ensures the linkage of phenotype and genotype (i.e., it ensures that each polymerase replicates only its own encoding gene to the exclusion of those in the other compartments). As a result, adaptive gains by the polymerase directly (and proportionally) translate into genetic amplification of the encoding polymerase gene. CSR has proven to be a useful strategy for the directed evolution of polymerases directly from diverse repertoires of polymerase genes. In this chapter, we describe some of the CSR protocols used successfully to evolve variants of T. aquaticus Pol I (Taq) polymerase with novel and useful properties, such as increased thermostability or resistance to the potent inhibitor, heparin, from a repertoire of randomly mutated Taq polymerase genes. PMID:17041269

  3. Proline accumulation, ions dynamics and sodium root-shoot partition and compartmentation

    Directory of Open Access Journals (Sweden)

    Jesus Emanuel eBojorquez Quintal

    2014-11-01

    Full Text Available Despite its economic relevance, little is known about salt tolerance mechanisms in pepper plants. To address this question, we compared differences in responses to NaCl in two Capsicum chinense varieties: Rex (tolerant and Chichen-Itza (sensitive. Under salt stress (150 mM NaCl over 7 days roots of Rex variety accumulated 50 times more compatible solutes such as proline compared to Chichen-Itza. Mineral analysis indicated that Na+ is restricted to roots by preventing its transport to leaves. Fluorescence analysis suggested an efficient Na+ compartmentalization in vacuole-like structures and in small intracellular compartments in roots of Rex variety. At the same time, Na+ in Chichen-Itza plants was compartmentalized in the apoplast, suggesting substantial Na+ extrusion. Rex variety was found to retain more K+ in its roots under salt stress according to a mineral analysis and microelectrode ion flux estimation (MIFE. Vanadate-sensitive H+ efflux was higher in Chichen-Itza variety plants, suggesting a higher activity of the plasma membrane H+-ATPase, which fuels the extrusion of Na+, and, possibly, also the re-uptake of K+. Our results suggest a combination of stress tolerance mechanisms, in order to alleviate the salt-induced injury. Furthermore, Na+ extrusion to apoplast does not appear to be an efficient strategy for salt tolerance in pepper plants.

  4. Metabolism of monoterpenes: evidence for compartmentation of l-menthone metabolism in peppermint (Mentha piperita) leaves

    Energy Technology Data Exchange (ETDEWEB)

    Martinkus, C.; Croteau, R.

    1981-01-01

    Previous studies have shown that the monoterpene ketone l-(G-/sup 3/H)-menthone is reduced to the epimeric alcohols l-menthol and d-neomenthol in leaf discs of flowering peppermint (Mentha piperita L.), and that a portion of the menthol is converted to menthyl acetate while the bulk of the neomenthol is transformed to neomenthyl-..beta..-D-glucoside. When l-(3-/sup 3/H)menthol and d-(3-/sup 3/H)neomenthol are separately administered to leaf discs, both menthyl and neomenthyl acetates and menthyl and neomenthyl glucosides are formed with nearly equal facility, suggesting that the metabolic specificity observed with the ketone precursor was not a function of the specificity of the transglucosylase or transacetylase but rather a result of compartmentation of each stereospecific dehydrogenase with the appropriate transferase. Co-purification of the acceptor-mediated activities, and differential activation and inhibition studies, provided strong evidence that the same UDP-glucose-dependent enzyme could transfer glucose to either l-menthol or d-neometnthol. These results demonstrate that the specific in vivo conversion of l-menthone to l-menthyl acetate and d-neomenthyl-..beta..-D-glucoside cannot be attributed to the selectivity of the transferases, and they clearly indicate that the metabolic specificity observed is a result of compartmentation effects.

  5. Compartmentalized Fluid Flow In The Nevado Del Ruiz Volcano Hydrothermal System(S)

    Science.gov (United States)

    Zuluaga, C. A.; Mejia, E.

    2011-12-01

    Combination of several extensive and compressive fault/fracture systems with different lithologic units compartmentalized the hydrothermal system(s) in the vicinity of the Nevado del Ruiz volcano. Three main fault/fracture systems are observed in the Ruiz volcano area, a N10°-20°E system (San Jerónimo and Palestina faults), a N40°-60°W system (Villamaría-Termales, San Ramón, Nereidas, Río Claro, San Eugenio and Campoalegrito faults), and a N60°-80°E system (Santa Rosa fault). The NW trend system act as the main path for fluid circulation, location of faults and fractures belonging to this system and their intersections with other fault systems and/or with lithologic contacts control hot springs location. The observed fault location and hot spring location pattern allow to subdivide the hydrothermal system(s) in at least five blocks. In the southernmost block, hot springs are mostly located in one of the four quadrants originated by fault intersections suggesting that there is a compartmentalization into higher and lower permeability quadrants. It is still unknown if all blocks belong to the same hydrothermal system or if there is more than one hydrothermal system.

  6. Modeling the Kinetics of a Memory-Associated Immediate Early Gene's Compartmental Expression After Sensory Experience

    Science.gov (United States)

    Willats, Adam; Ivanova, Tamara; Prinz, Astrid; Liu, Robert

    2015-03-01

    Immediate Early Genes (IEGs) are rapidly and transiently transcribed in neurons after a sensory experience. Some of these genes act as effector IEGs, which mediate specific effects on cellular function. Arc is one such effector IEG that is essential for synaptic plasticity and memory consolidation in hippocampus and cortex. The expression of Arc in neurons has previously been examined using an imaging method known as Compartmental Analysis of Temporal Fluorescent In-Situ Hybridization. Previous work found that the time course of Arc expression within the nuclear and perinuclear cytoplasmic compartments of a neuron is altered by prior sensory experience. We explore a simple model of the kinetics of IEG transcription and nuclear export, with the aim of eventually uncovering possible mechanisms for how experience alters expression kinetics. Thus far, we characterize our compartmental model using phase-plane analysis and validate it against several IEG expression data sets, including one where prior experience with vocalizing mice alters the time course of call-induced Arc expression in the auditory cortex of a listening mouse. Our model provides a framework to explore why Arc expression may change depending on a receiver's past sound experience and internal state. Adam Willats was supported by NIH Training Grant 5T90DA032466. This research was also supported by NIDCD R01 DC8343.

  7. 4D maximum a posteriori reconstruction in dynamic SPECT using a compartmental model-based prior

    International Nuclear Information System (INIS)

    A 4D ordered-subsets maximum a posteriori (OSMAP) algorithm for dynamic SPECT is described which uses a temporal prior that constrains each voxel's behaviour in time to conform to a compartmental model. No a priori limitations on kinetic parameters are applied; rather, the parameter estimates evolve as the algorithm iterates to a solution. The estimated parameters and time-activity curves are used within the reconstruction algorithm to model changes in the activity distribution as the camera rotates, avoiding artefacts due to inconsistencies of data between projection views. This potentially allows for fewer, longer-duration scans to be used and may have implications for noise reduction. The algorithm was evaluated qualitatively using dynamic 99mTc-teboroxime SPECT scans in two patients, and quantitatively using a series of simulated phantom experiments. The OSMAP algorithm resulted in images with better myocardial uniformity and definition, gave time-activity curves with reduced noise variations, and provided wash-in parameter estimates with better accuracy and lower statistical uncertainty than those obtained from conventional ordered-subsets expectation-maximization (OSEM) processing followed by compartmental modelling. The new algorithm effectively removed the bias in k21 estimates due to inconsistent projections for sampling schedules as slow as 60 s per timeframe, but no improvement in wash-out parameter estimates was observed in this work. The proposed dynamic OSMAP algorithm provides a flexible framework which may benefit a variety of dynamic tomographic imaging applications. (author)

  8. Cerebrospinal fluid analysis in the HIV infection and compartmentalization of HIV in the central nervous system

    Directory of Open Access Journals (Sweden)

    Sérgio Monteiro de Almeida

    2015-07-01

    Full Text Available The nervous system plays an important role in HIV infection. The purpose of this review is to discuss the indications for cerebrospinal fluid (CSF analysis in HIV infection in clinical practice. CSF analysis in HIV infection is indicated for the diagnosis of opportunistic infections and co-infections, diagnosis of meningitis caused by HIV, quantification of HIV viral load, and analysis of CNS HIV compartmentalization. Although several CSF biomarkers have been investigated, none are clinically applicable. The capacity of HIV to generate genetic diversity, in association with the constitutional characteristics of the CNS, facilitates the generation of HIV quasispecies in the CNS that are distinct from HIV in the systemic circulation. CSF analysis has a well-defined and valuable role in the diagnosis of CNS infections in HIV/AIDS patients. Further research is necessary to establish a clinically applicable biomarker for the diagnosis of HIV-associated neurocognitive disorders.

  9. Modeling non-stationary conditions for carbohydrate compartmentation and export in maize leaf

    International Nuclear Information System (INIS)

    Distribution of photosynthetic carbon, in an exporting maize leaf (Zea mays), was modeled from the analysis of radioactivity chase experiments after a 14CO2 pulse labeling. A model taking into account four compartments -precursor pool, starch pool and two exchangeable sucrose pools- was proposed. It brought significant improvements compared to earlier attempts in that it allowed direct calculation for all of the compartment sizes and transfer coefficients, without any additional simplifying hypothesis. This more comprehensive version was used to test the influence of various procedures or assumptions frequently chosen when performing compartmental analysis with an exporting leaf. Most of the calculations appeared to be dependent on a good estimate of the asymptote value, so a critical point appeared to be the length of the chase period

  10. A comprehensive compartmental model of blood glucose regulation for healthy and type 2 diabetic subjects

    DEFF Research Database (Denmark)

    Vahidi, O; Kwok, K E; Gopaluni, R B;

    2016-01-01

    We have expanded a former compartmental model of blood glucose regulation for healthy and type 2 diabetic subjects. The former model was a detailed physiological model which considered the interactions of three substances, glucose, insulin and glucagon on regulating the blood sugar. The main...... drawback of the former model was its restriction on the route of glucose entrance to the body which was limited to the intravenous glucose injection. To handle the oral glucose intake, we have added a model of glucose absorption in the gastrointestinal tract to the former model to address the resultant...... variations of blood glucose concentrations following an oral glucose intake. Another model representing the incretins production in the gastrointestinal tract along with their hormonal effects on boosting pancreatic insulin production is also added to the former model. We have used two sets of clinical data...

  11. Heterogeneity and compartmentalization of Pneumocystis carinii f. sp. hominis genotypes in autopsy lungs

    DEFF Research Database (Denmark)

    Helweg-Larsen, J; Lundgren, Bettina; Lundgren, Jens Dilling

    2001-01-01

    The extent and importance of genotype heterogeneity of Pneumocystis carinii f. sp. hominis within lungs have not previously been investigated. Two hundred forty PCR clones obtained from respiratory specimens and lung segments from three patients with fatal P. carinii pneumonia were investigated....... Not all genotypes present in the lungs at autopsy were detected in the diagnostic respiratory samples. Compartmentalization of specific ITS and mtLSU rRNA sequence types was observed in different lung segments. In conclusion, the interpretation of genotype data and in particular ITS sequence types...... in the assessment of epidemiological questions should be cautious since genotyping done on respiratory samples cannot a priori be assumed to represent all genotypes present within the lung....

  12. Aspects of astrocyte energy metabolism, amino acid neurotransmitter homoeostasis and metabolic compartmentation

    DEFF Research Database (Denmark)

    Kreft, Marko; Bak, Lasse Kristoffer; Waagepetersen, Helle S;

    2012-01-01

    Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy-generating pat......-generating pathways and amino acid homoeostasis. A discussion of the impact that uptake of neurotransmitter glutamate may have on these pathways is included along with a section on metabolic compartmentation.......Astrocytes are key players in brain function; they are intimately involved in neuronal signalling processes and their metabolism is tightly coupled to that of neurons. In the present review, we will be concerned with a discussion of aspects of astrocyte metabolism, including energy...

  13. Sequence Stratigraphy of the Dakota Sandstone, Eastern San Juan Basin, New Mexico, and its Relationship to Reservoir Compartmentalization

    Energy Technology Data Exchange (ETDEWEB)

    Varney, Peter J.

    2002-04-23

    This research established the Dakota-outcrop sequence stratigraphy in part of the eastern San Juan Basin, New Mexico, and relates reservoir quality lithologies in depositional sequences to structure and reservoir compartmentalization in the South Lindrith Field area. The result was a predictive tool that will help guide further exploration and development.

  14. Dynamics of the risk of smoking-induced lung cancer : A compartmental hidden markov model for longitudinal analysis

    NARCIS (Netherlands)

    Chadeau-Hyam, Marc; Tubert-Bitter, Pascale; Guihenneuc-Jouyaux, Chantal; Campanella, Gianluca; Richardson, Sylvia; Vermeulen, Roel; De Iorio, Maria; Galea, Sandro; Vineis, Paolo

    2014-01-01

    BACKGROUND:: To account for the dynamic aspects of carcinogenesis, we propose a compartmental hidden Markov model in which each person is healthy, asymptomatically affected, diagnosed, or deceased. Our model is illustrated using the example of smoking-induced lung cancer. METHODS:: The model was fit

  15. 21 CFR 888.3535 - Knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis.

    Science.gov (United States)

    2010-04-01

    .../polymer porous-coated uncemented prosthesis. 888.3535 Section 888.3535 Food and Drugs FOOD AND DRUG... prosthesis. (a) Identification. A knee joint femorotibial (uni-compartmental) metal/polymer porous-coated uncemented prosthesis is a device intended to be implanted to replace part of a knee joint. The device...

  16. Compartmentalization of oxidative stress and antioxidant defense in the larval gut of Spodoptera littoralis.

    Science.gov (United States)

    Krishnan, Natraj; Sehnal, Frantisek

    2006-09-01

    Allelochemicals play important roles in the plant defense against herbivorous insects. They act as feeding deterrents, interfere with digestion and nutrient absorption, and cause production of potentially dangerous oxidative radicals. This study demonstrates that the distributions of oxidative radicals and of the antioxidant enzymes that eliminate them are compartmentalized in the digestive tract of Spodoptera littoralis larvae. Feeding on diets supplemented with the tannic acid (TA), alpha-solanine, and demissidine, respectively, did not affect the rate of food passage through the digestive tract of larvae but 1.25, 2.5, and 5% TA evoked a strong oxidative response. The amount of the superoxide anion in the foregut tissue and content increased up to 70-fold and the titer of total peroxides in the foregut content about 3-fold. This oxidative stress was associated with enhanced carbonyl content in the foregut tissue proteins, indicative of certain tissue deterioration. Extensive foregut damage was probably prevented by elevated activity of the glutathione S-transferase peroxidase. A complex antioxidant response was elicited in the midgut. The activities of superoxide dismutase and catalase increased significantly in the midgut tissue and content, and the activity of ascorbate peroxidase rose in the midgut tissue. The enzymes apparently eliminated oxidative radicals passing to midgut from the foregut with the food bolus and thereby prevented carbonylation of the midgut proteins. We postulate that the generation of oxidative radicals in the foregut and the induction of antioxidant defense in the midgut are controlled processes and that their compartmentalization is an important functional feature of the digestive tract. The glycoalkaloid alpha-solanine and the aglycone demissidine applied at 0.05 and 0.1% concentrations had no effect on any of the examined parameters.

  17. The construction of next-generation matrices for compartmental epidemic models.

    Science.gov (United States)

    Diekmann, O; Heesterbeek, J A P; Roberts, M G

    2010-06-01

    The basic reproduction number (0) is arguably the most important quantity in infectious disease epidemiology. The next-generation matrix (NGM) is the natural basis for the definition and calculation of (0) where finitely many different categories of individuals are recognized. We clear up confusion that has been around in the literature concerning the construction of this matrix, specifically for the most frequently used so-called compartmental models. We present a detailed easy recipe for the construction of the NGM from basic ingredients derived directly from the specifications of the model. We show that two related matrices exist which we define to be the NGM with large domain and the NGM with small domain. The three matrices together reflect the range of possibilities encountered in the literature for the characterization of (0). We show how they are connected and how their construction follows from the basic model ingredients, and establish that they have the same non-zero eigenvalues, the largest of which is the basic reproduction number (0). Although we present formal recipes based on linear algebra, we encourage the construction of the NGM by way of direct epidemiological reasoning, using the clear interpretation of the elements of the NGM and of the model ingredients. We present a selection of examples as a practical guide to our methods. In the appendix we present an elementary but complete proof that (0) defined as the dominant eigenvalue of the NGM for compartmental systems and the Malthusian parameter r, the real-time exponential growth rate in the early phase of an outbreak, are connected by the properties that (0) > 1 if and only if r > 0, and (0) = 1 if and only if r = 0. PMID:19892718

  18. Bioaccessibility of selenium after human ingestion in relation to its chemical species and compartmentalization in maize.

    Science.gov (United States)

    Mombo, Stéphane; Schreck, Eva; Dumat, Camille; Laplanche, Christophe; Pierart, Antoine; Longchamp, Mélanie; Besson, Philippe; Castrec-Rouelle, Maryse

    2016-06-01

    Selenium is a micronutrient needed by all living organisms including humans, but often present in low concentration in food with possible deficiency. From another side, at higher concentrations in soils as observed in seleniferous regions of the world, and in function of its chemical species, Se can also induce (eco)toxicity. Root Se uptake was therefore studied in function of its initial form for maize (Zea mays L.), a plant widely cultivated for human and animal food over the world. Se phytotoxicity and compartmentalization were studied in different aerial plant tissues. For the first time, Se oral human bioaccessibility after ingestion was assessed for the main Se species (Se(IV) and Se(VI)) with the BARGE ex vivo test in maize seeds (consumed by humans), and in stems and leaves consumed by animals. Corn seedlings were cultivated in hydroponic conditions supplemented with 1 mg L(-1) of selenium (Se(IV), Se(VI), Control) for 4 months. Biomass, Se concentration, and bioaccessibility were measured on harvested plants. A reduction in plant biomass was observed under Se treatments compared to control, suggesting its phytotoxicity. This plant biomass reduction was higher for selenite species than selenate, and seed was the main affected compartment compared to control. Selenium compartmentalization study showed that for selenate species, a preferential accumulation was observed in leaves, whereas selenite translocation was very limited toward maize aerial parts, except in the seeds where selenite concentrations are generally high. Selenium oral bioaccessibility after ingestion fluctuated from 49 to 89 % according to the considered plant tissue and Se species. Whatever the tissue, selenate appeared as the most human bioaccessible form. A potential Se toxicity was highlighted for people living in seleniferous regions, this risk being enhanced by the high Se bioaccessibility. PMID:26387097

  19. Pathway Compartmentalization in Peroxisome of Saccharomyces cerevisiae to Produce Versatile Medium Chain Fatty Alcohols.

    Science.gov (United States)

    Sheng, Jiayuan; Stevens, Joseph; Feng, Xueyang

    2016-01-01

    Fatty alcohols are value-added chemicals and important components of a variety of industries, which have a >3 billion-dollar global market annually. Long chain fatty alcohols (>C12) are mainly used in surfactants, lubricants, detergents, pharmaceuticals and cosmetics while medium chain fatty alcohols (C6-C12) could be used as diesel-like biofuels. Microbial production of fatty alcohols from renewable feedstock stands as a promising strategy to enable sustainable supply of fatty alcohols. In this study, we report, for the first time, that medium chain fatty alcohols could be produced in yeast via targeted expression of a fatty acyl-CoA reductase (TaFAR) in the peroxisome of Saccharomyces cerevisiae. By tagging TaFAR enzyme with peroxisomal targeting signal peptides, the TaFAR could be compartmentalized into the matrix of the peroxisome to hijack the medium chain fatty acyl-CoA generated from the beta-oxidation pathway and convert them to versatile medium chain fatty alcohols (C10 &C12). The overexpression of genes encoding PEX7 and acetyl-CoA carboxylase further improved fatty alcohol production by 1.4-fold. After medium optimization in fed-batch fermentation using glucose as the sole carbon source, fatty alcohols were produced at 1.3 g/L, including 6.9% 1-decanol, 27.5% 1-dodecanol, 2.9% 1-tetradecanol and 62.7% 1-hexadecanol. This work revealed that peroxisome could be engineered as a compartmentalized organelle for producing fatty acid-derived chemicals in S. cerevisiae. PMID:27230732

  20. Compartmentalization and Cell Division through Molecular Discreteness and Crowding in a Catalytic Reaction Network

    Directory of Open Access Journals (Sweden)

    Atsushi Kamimura

    2014-10-01

    Full Text Available Explanation of the emergence of primitive cellular structures from a set of chemical reactions is necessary to unveil the origin of life and to experimentally synthesize protocells. By simulating a cellular automaton model with a two-species hypercycle, we demonstrate the reproduction of a localized cluster; that is, a protocell with a growth-division process emerges when the replication and degradation speeds of one species are respectively slower than those of the other species, because of overcrowding of molecules as a natural outcome of the replication. The protocell exhibits synchrony between its division process and replication of the minority molecule. We discuss the effects of the crowding molecule on the formation of primitive structures. The generality of this result is demonstrated through the extension of our model to a hypercycle with three molecular species, where a localized layered structure of molecules continues to divide, triggered by the replication of a minority molecule at the center.

  1. Compartmentalization and Cell Division through Molecular Discreteness and Crowding in a Catalytic Reaction Network

    OpenAIRE

    Atsushi Kamimura; Kunihiko Kaneko

    2014-01-01

    Explanation of the emergence of primitive cellular structures from a set of chemical reactions is necessary to unveil the origin of life and to experimentally synthesize protocells. By simulating a cellular automaton model with a two-species hypercycle, we demonstrate the reproduction of a localized cluster; that is, a protocell with a growth-division process emerges when the replication and degradation speeds of one species are respectively slower than those of the other species, because of ...

  2. The Early Expression of HLA-DR and CD64 Myeloid Markers Is Specifically Compartmentalized in the Blood and Lungs of Patients with Septic Shock

    Directory of Open Access Journals (Sweden)

    Tomasz Skirecki

    2016-01-01

    Full Text Available Identification of reliable biomarkers is key to guide targeted therapies in septic patients. Expression monitoring of monocyte HLA-DR and neutrophil CD64 could fulfill the above need. However, it is unknown whether their expression on circulating cells reflects the status of tissue resident cells. We compared expressions of HLA-DR and CD64 markers in the circulation and airways of septic shock patients and evaluated their outcome prognostic value. The expression of CD64 on neutrophils and HLA-DR on monocytes was analyzed in the peripheral blood and mini-bronchoalveolar lavage fluid cells by flow cytometry. Twenty-seven patients with septic shock were enrolled into the study. The fluorescence intensity of HLA-DR on circulating monocytes was 3.5-fold lower than on the pulmonary monocytes (p=0.01. The expression of CD64 on circulating and airway neutrophils was similar (p=0.47. Only the expression of CD64 on circulating neutrophils was higher in nonsurvivors versus survivors (2.8-fold; p=0.031. Pulmonary monocytes display a higher level of HLA-DR activation compared to peripheral blood monocytes but the expression of neutrophil CD64 is similar on lung and circulating cells. Death in septic patients was effectively predicted by neutrophil CD64 but not monocytic HLA-DR. Prognostic value of cellular activation markers in septic shock appears to strongly depend on their level of compartmentalization.

  3. The Early Expression of HLA-DR and CD64 Myeloid Markers Is Specifically Compartmentalized in the Blood and Lungs of Patients with Septic Shock

    Science.gov (United States)

    Mikaszewska-Sokolewicz, Małgorzata; Hoser, Grażyna; Zielińska-Borkowska, Urszula

    2016-01-01

    Identification of reliable biomarkers is key to guide targeted therapies in septic patients. Expression monitoring of monocyte HLA-DR and neutrophil CD64 could fulfill the above need. However, it is unknown whether their expression on circulating cells reflects the status of tissue resident cells. We compared expressions of HLA-DR and CD64 markers in the circulation and airways of septic shock patients and evaluated their outcome prognostic value. The expression of CD64 on neutrophils and HLA-DR on monocytes was analyzed in the peripheral blood and mini-bronchoalveolar lavage fluid cells by flow cytometry. Twenty-seven patients with septic shock were enrolled into the study. The fluorescence intensity of HLA-DR on circulating monocytes was 3.5-fold lower than on the pulmonary monocytes (p = 0.01). The expression of CD64 on circulating and airway neutrophils was similar (p = 0.47). Only the expression of CD64 on circulating neutrophils was higher in nonsurvivors versus survivors (2.8-fold; p = 0.031). Pulmonary monocytes display a higher level of HLA-DR activation compared to peripheral blood monocytes but the expression of neutrophil CD64 is similar on lung and circulating cells. Death in septic patients was effectively predicted by neutrophil CD64 but not monocytic HLA-DR. Prognostic value of cellular activation markers in septic shock appears to strongly depend on their level of compartmentalization.

  4. Cytoplasmic localization of Hug1p, a negative regulator of the MEC1 pathway, coincides with the compartmentalization of Rnr2p–Rnr4p

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, William B. [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Hughes, Bridget Todd; Au, Wei Chun; Sakelaris, Sally [Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Kerscher, Oliver [Biology Department, The College of William and Mary, Williamsburg, VA 23185 (United States); Benton, Michael G., E-mail: benton@lsu.edu [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 (United States); Basrai, Munira A., E-mail: basraim@mail.nih.gov [Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2013-10-04

    Highlights: •Hug1p overexpression sensitizes wild-type cells to DNA damage and hydroxyurea (HU). •Expression of Hug1p in response to HU treatment is delayed relative to Rnr3p. •MEC1 pathway genes are required for cytoplasmic localization of Hug1p. •Hug1p subcellular compartmentalization to the cytoplasm coincides with Rnr2p–Rnr4p. -- Abstract: The evolutionarily conserved MEC1 checkpoint pathway mediates cell cycle arrest and induction of genes including the RNR (Ribonucleotide reductase) genes and HUG1 (Hydroxyurea, ultraviolet, and gamma radiation) in response to DNA damage and replication arrest. Rnr complex activity is in part controlled by cytoplasmic localization of the Rnr2p–Rnr4p subunits and inactivation of negative regulators Sml1p and Dif1p upon DNA damage and hydroxyurea (HU) treatment. We previously showed that a deletion of HUG1 rescues lethality of mec1Δ and suppresses dun1Δ strains. In this study, multiple approaches demonstrate the regulatory response of Hug1p to DNA damage and HU treatment and support its role as a negative effector of the MEC1 pathway. Consistent with our hypothesis, wild-type cells are sensitive to DNA damage and HU when HUG1 is overexpressed. A Hug1 polyclonal antiserum reveals that HUG1 encodes a protein in budding yeast and its MEC1-dependent expression is delayed compared to the rapid induction of Rnr3p in response to HU treatment. Cell biology and subcellular fractionation experiments show localization of Hug1p-GFP to the cytoplasm upon HU treatment. The cytoplasmic localization of Hug1p-GFP is dependent on MEC1 pathway genes and coincides with the cytoplasmic localization of Rnr2p–Rnr4p. Taken together, the genetic interactions, gene expression, and localization studies support a novel role for Hug1p as a negative regulator of the MEC1 checkpoint response through its compartmentalization with Rnr2p–Rnr4p.

  5. Cytoplasmic localization of Hug1p, a negative regulator of the MEC1 pathway, coincides with the compartmentalization of Rnr2p–Rnr4p

    International Nuclear Information System (INIS)

    Highlights: •Hug1p overexpression sensitizes wild-type cells to DNA damage and hydroxyurea (HU). •Expression of Hug1p in response to HU treatment is delayed relative to Rnr3p. •MEC1 pathway genes are required for cytoplasmic localization of Hug1p. •Hug1p subcellular compartmentalization to the cytoplasm coincides with Rnr2p–Rnr4p. -- Abstract: The evolutionarily conserved MEC1 checkpoint pathway mediates cell cycle arrest and induction of genes including the RNR (Ribonucleotide reductase) genes and HUG1 (Hydroxyurea, ultraviolet, and gamma radiation) in response to DNA damage and replication arrest. Rnr complex activity is in part controlled by cytoplasmic localization of the Rnr2p–Rnr4p subunits and inactivation of negative regulators Sml1p and Dif1p upon DNA damage and hydroxyurea (HU) treatment. We previously showed that a deletion of HUG1 rescues lethality of mec1Δ and suppresses dun1Δ strains. In this study, multiple approaches demonstrate the regulatory response of Hug1p to DNA damage and HU treatment and support its role as a negative effector of the MEC1 pathway. Consistent with our hypothesis, wild-type cells are sensitive to DNA damage and HU when HUG1 is overexpressed. A Hug1 polyclonal antiserum reveals that HUG1 encodes a protein in budding yeast and its MEC1-dependent expression is delayed compared to the rapid induction of Rnr3p in response to HU treatment. Cell biology and subcellular fractionation experiments show localization of Hug1p-GFP to the cytoplasm upon HU treatment. The cytoplasmic localization of Hug1p-GFP is dependent on MEC1 pathway genes and coincides with the cytoplasmic localization of Rnr2p–Rnr4p. Taken together, the genetic interactions, gene expression, and localization studies support a novel role for Hug1p as a negative regulator of the MEC1 checkpoint response through its compartmentalization with Rnr2p–Rnr4p

  6. Compartmental modeling of PAH transport in soil column experiments under variably-saturated flow conditions

    Science.gov (United States)

    Sartori, F.; Sericano, J. L.; Wade, T. L.; Mohanty, B. P.

    2012-12-01

    Knowledge about the mobilization of polycyclic aromatic hydrocarbons (PAH) from PAH-laden soils or sediments is important to understand their bioavailability, and ultimately assess the environmental risk of PAH transport from surface soils into the groundwater. The transport and kinetics of three PAH from a spiked soil layer (2-3 cm soil depth), Phenanthrene-d10 (1900 ng/g), Naphthalene-d8 (1500 ng/g), and Pyrene-d10 (1800 ng/g), were investigated by performing a series of 8 rainfall events during 25 days in two large, replicate soil columns (length: 35 cm; diameter: 14.5 cm; 1 Pore Volume [PV]=2.29 L) under variably-saturated flow conditions. The water-methanol displacing solutions were at volumetric fractions of 0.3 and 0.6 during day 1 (E1) through E8 and E12-E22, respectively. Soil matric potential (h) was monitored at 5-cm and 20-cm depth and volumetric water content (θ) at 12.5-cm and 27.5-cm depth. Soil solution was sampled at 5 cm- (n=46) and 27.5-cm depth (n=46), and the effluent at the bottom of the column (n=163). HYDRUS-1D was used for inverse modeling of h and θ data and to predict θ at specific times and soil depth increments. First-order kinetics, compartmental models describing the transfer of PAH from the soil compartment to the soil solution compartment (desorption) and vice versa (sorption), were used to estimate mass transfer rates (φs, sorption; φd, desorption; φe, elimination), PAH mass in each compartment, and partition coefficients (Kd). Phenanthrene breakthrough curve could be interpreted through a two-parameter, two-compartment model corresponding to the common two-site sorption model, whose parameter estimates (and 95% confidence intervals) were φd=2.72 (2.31, 3.19) PV-1 and φe=4.67 (3.82, 5.7 ) PV-1. Naphthalene breakthrough curve followed a simple one-compartment elimination model, φe=2.0 (1.9, 2.1) PV-1, and that of Pyrene a three-parameter, two-compartment model, φs=0.0454 (0.00853, 0.0603) PV-1, φd=0.165 (0.0319, 0.855) PV

  7. A Compartmental Comparison of Major Lipid Species in a Coral-Symbiodinium Endosymbiosis: Evidence that the Coral Host Regulates Lipogenesis of Its Cytosolic Lipid Bodies.

    Directory of Open Access Journals (Sweden)

    Hung-Kai Chen

    Full Text Available The lipid body (LB formation in the host coral gastrodermal cell cytoplasm is a hallmark of the coral-Symbiodinium endosymbiosis, and such lipid-based entities are not found in endosymbiont-free cnidarian cells. Therefore, the elucidation of lipogenesis regulation in LBs and how it is related to the lipid metabolism of the host and endosymbiont could provide direct insight to understand the symbiosis mechanism. Herein, the lipid composition of host cells of the stony coral Euphyllia glabrescens, as well as that of their cytoplasmic LBs and in hospite Symbiodinium populations, was examined by high performance liquid chromatography (HPLC and gas chromatography/mass spectrometry (GC/MS, and six major lipid species were identified: wax esters, sterol esters, triacylglycerols, cholesterols, free fatty acids, and phospholipids. Their concentrations differed significantly between host coral cells, LBs, and Symbiodinium, suggesting compartmental regulation. WE were only present in the host coral and were particularly highly concentrated in LBs. Amongst the four species of WE, the monoene R = C18:1/R = C16 was found to be LB-specific and was not present in the host gastrodermal cell cytoplasm. Furthermore, the acyl pool profiles of the individual LB lipid species were more similar, but not equal to, those of the host gastrodermal cells in which they were located, indicating partially autonomous lipid metabolism in these LBs. Nevertheless, given the overall similarity in the host gastrodermal cell and LB lipid profiles, these data suggest that a significant portion of the LB lipids may be of host coral origin. Finally, lipid profiles of the in hospite Symbiodinium populations were significantly distinct from those of the cultured Symbiodinium, potentially suggesting a host regulation effect that may be fundamental to lipid metabolism in endosymbiotic associations involving clade C Symbiodinium.

  8. A Compartmental Comparison of Major Lipid Species in a Coral-Symbiodinium Endosymbiosis: Evidence that the Coral Host Regulates Lipogenesis of Its Cytosolic Lipid Bodies.

    Science.gov (United States)

    Chen, Hung-Kai; Song, Shin-Ni; Wang, Li-Hsueh; Mayfield, Anderson B; Chen, Yi-Jyun; Chen, Wan-Nan U; Chen, Chii-Shiarng

    2015-01-01

    The lipid body (LB) formation in the host coral gastrodermal cell cytoplasm is a hallmark of the coral-Symbiodinium endosymbiosis, and such lipid-based entities are not found in endosymbiont-free cnidarian cells. Therefore, the elucidation of lipogenesis regulation in LBs and how it is related to the lipid metabolism of the host and endosymbiont could provide direct insight to understand the symbiosis mechanism. Herein, the lipid composition of host cells of the stony coral Euphyllia glabrescens, as well as that of their cytoplasmic LBs and in hospite Symbiodinium populations, was examined by high performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS), and six major lipid species were identified: wax esters, sterol esters, triacylglycerols, cholesterols, free fatty acids, and phospholipids. Their concentrations differed significantly between host coral cells, LBs, and Symbiodinium, suggesting compartmental regulation. WE were only present in the host coral and were particularly highly concentrated in LBs. Amongst the four species of WE, the monoene R = C18:1/R = C16 was found to be LB-specific and was not present in the host gastrodermal cell cytoplasm. Furthermore, the acyl pool profiles of the individual LB lipid species were more similar, but not equal to, those of the host gastrodermal cells in which they were located, indicating partially autonomous lipid metabolism in these LBs. Nevertheless, given the overall similarity in the host gastrodermal cell and LB lipid profiles, these data suggest that a significant portion of the LB lipids may be of host coral origin. Finally, lipid profiles of the in hospite Symbiodinium populations were significantly distinct from those of the cultured Symbiodinium, potentially suggesting a host regulation effect that may be fundamental to lipid metabolism in endosymbiotic associations involving clade C Symbiodinium. PMID:26218797

  9. Integrated compartmental model for describing the transport of solute in a fractured porous medium

    International Nuclear Information System (INIS)

    This report documents a model, FRACPORT, that simulates the transport of a solute through a fractured porous matrix. The model should be useful in analyzing the possible transport of radionuclides from shallow-land burial sites in humid environments. The use of the model is restricted to transport through saturated zones. The report first discusses the general modeling approach used, which is based on the Integrated Compartmental Method. The basic equations of solute transport are then presented. The model, which assumes a known water velocity field, solves these equations on two different time scales; one related to rapid transport of solute along fractures and the other related to slower transport through the porous matrix. FRACPORT is validated by application to a simple example of fractured porous medium transport that has previously been analyzed by other methods. Then its utility is demonstrated in analyzing more complex cases of pulses of solute into a fractured matrix. The report serves as a user's guide to FRACPORT. A detailed description of data input, along with a listing of input for a sample problem, is provided. 16 references, 18 figures, 3 tables

  10. Linear least squares compartmental-model-independent parameter identification in PET.

    Science.gov (United States)

    Thie, J A; Smith, G T; Hubner, K F

    1997-02-01

    A simplified approach involving linear-regression straight-line parameter fitting of dynamic scan data is developed for both specific and nonspecific models. Where compartmental-model topologies apply, the measured activity may be expressed in terms of: its integrals, plasma activity and plasma integrals--all in a linear expression with macroparameters as coefficients. Multiple linear regression, as in spreadsheet software, determines parameters for best data fits. Positron emission tomography (PET)-acquired gray-matter images in a dynamic scan are analyzed: both by this method and by traditional iterative nonlinear least squares. Both patient and simulated data were used. Regression and traditional methods are in expected agreement. Monte-Carlo simulations evaluate parameter standard deviations, due to data noise, and much smaller noise-induced biases. Unique straight-line graphical displays permit visualizing data influences on various macroparameters as changes in slopes. Advantages of regression fitting are: simplicity, speed, ease of implementation in spreadsheet software, avoiding risks of convergence failures or false solutions in iterative least squares, and providing various visualizations of the uptake process by straight line graphical displays. Multiparameter model-independent analyses on lesser understood systems is also made possible.

  11. A Tale of Genome Compartmentalization: The Evolution of Virulence Clusters in Smut Fungi.

    Science.gov (United States)

    Dutheil, Julien Y; Mannhaupt, Gertrud; Schweizer, Gabriel; M K Sieber, Christian; Münsterkötter, Martin; Güldener, Ulrich; Schirawski, Jan; Kahmann, Regine

    2016-03-01

    Smut fungi are plant pathogens mostly parasitizing wild species of grasses as well as domesticated cereal crops. Genome analysis of several smut fungi including Ustilago maydis revealed a singular clustered organization of genes encoding secreted effectors. In U. maydis, many of these clusters have a role in virulence. Reconstructing the evolutionary history of clusters of effector genes is difficult because of their intrinsically fast evolution, which erodes the phylogenetic signal and homology relationships. Here, we describe the use of comparative evolutionary analyses of quality draft assemblies of genomes to study the mechanisms of this evolution. We report the genome sequence of a South African isolate of Sporisorium scitamineum, a smut fungus parasitizing sugar cane with a phylogenetic position intermediate to the two previously sequenced species U. maydis and Sporisorium reilianum. We show that the genome of S. scitamineum contains more and larger gene clusters encoding secreted effectors than any previously described species in this group. We trace back the origin of the clusters and find that their evolution is mainly driven by tandem gene duplication. In addition, transposable elements play a major role in the evolution of the clustered genes. Transposable elements are significantly associated with clusters of genes encoding fast evolving secreted effectors. This suggests that such clusters represent a case of genome compartmentalization that restrains the activity of transposable elements on genes under diversifying selection for which this activity is potentially beneficial, while protecting the rest of the genome from its deleterious effect. PMID:26872771

  12. PGI2 synthesis and excretion in dog kidney: evidence for renal PG compartmentalization

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, R.M.; Nasjletti, A.; Heerdt, P.M.; Baer, P.G.

    1986-01-01

    To assess the concept of compartmentalization of renal prostaglandins (PG), we compared entry of PGE2 and the PGI2 metabolite 6-keto-PGF1 alpha into the renal vascular and tubular compartments, in sodium pentobarbital-anesthetized dogs. Renal arterial 6-keto-PGF1 alpha infusion increased both renal venous and urinary 6-keto-PGF1 alpha outflow. In contrast, renal arterial infusion of arachidonic acid (AA) or bradykinin (BK) increased renal venous 6-keto-PGF1 alpha outflow but had no effect on its urinary outflow. Both urinary and renal venous PGE2 outflows increased during AA or BK infusion. Ureteral stopped-flow studies revealed no postglomerular 6-keto-PGF1 alpha entry into tubular fluid. During renal arterial infusion of (3H)PGI2 and inulin, first-pass 3H clearance was 40% of inulin clearance; 35% of urinary 3H was 6-keto-PGF1 alpha, and two other urinary metabolites were found. During renal arterial infusion of (3H)6-keto-PGF1 alpha and inulin, first-pass 3H clearance was 150% of inulin clearance; 75% of urinary 3H was 6-keto-PGF1 alpha, and only one other metabolite was found. We conclude that in the dog PGE2 synthesized in the kidney enters directly into both the renal vascular and tubular compartments, but 6-keto-PGF1 alpha of renal origin enters directly into only the renal vascular compartment.

  13. Hypothalamic metabolic compartmentation during appetite regulation as revealed by magnetic resonance imaging and spectroscopy methods

    Directory of Open Access Journals (Sweden)

    Blanca eLizarbe

    2013-06-01

    Full Text Available We review the role of neuroglial compartmentation and transcellular neurotransmitter cycling during hypothalamic appetite regulation as detected by Magnetic Resonance Imaging (MRI and Spectroscopy (MRS methods. We address first the neurochemical basis of neuroendocrine regulation in the hypothalamus and the orexigenic and anorexigenic feed-back loops that control appetite. Then we examine the main Magnetic Resonance Imaging and Spectroscopy strategies that have been used to investigate appetite regulation. Manganese enhanced magnetic resonance imaging (MEMRI, Blood oxygenation level dependent contrast (BOLD and Diffusion weighted magnetic resonance imaging (DWI have revealed Mn2+accumulations, augmented oxygen consumptions and astrocytic swelling in the hypothalamus under fasting conditions, respectively. High field 1H magnetic resonance in vivo, showed increased hypothalamic myo-inositol concentrations as compared to other cerebral structures. 1H and 13C high resolution magic angle spinning (HRMAS revealed increased neuroglial oxidative and glycolytic metabolism, as well as increased hypothalamic glutamatergic and GABAergic neurotransmissions under orexigenic stimulation. We propose here an integrative interpretation of all these findings suggesting that the neuroendocrine regulation of appetite is supported by important ionic and metabolic transcellular fluxes which begin at the tripartite orexigenic clefts and become extended spatially in the hypothalamus through astrocytic networks, becoming eventually MRI and MRS detectable.

  14. The Arab Spring: A Simple Compartmental Model for the Dynamics of a Revolution

    CERN Document Server

    Lang, John

    2012-01-01

    The self-immolation of Mohamed Bouazizi on December 17, 2011 in the small Tunisian city of Sidi Bouzid, set off a sequence of events culminating in the revolutions of the Arab Spring. It is widely believed that the Internet and social media played a critical role in the growth and success of protests that led to the downfall of the regimes in Egypt and Tunisia. However, the precise mechanisms by which these new media affected the course of events remain unclear. We introduce a simple compartmental model for the dynamics of a revolution in a dictatorial regime such as Tunisia or Egypt which takes into account the role of the Internet and social media. An elementary mathematical analysis of the model identifies four main parameter regions: stable police state, meta-stable police state, unstable police state, and failed state. We illustrate how these regions capture, at least qualitatively, a wide range of scenarios observed in the context of revolutionary movements by considering the revolutions in Tunisia and ...

  15. The Use of Metaphors in Poetry and Organization Theory: Toward De-Compartmentalization of Organizational Knowledge

    Directory of Open Access Journals (Sweden)

    Naveed Yazdani

    2011-09-01

    Full Text Available Since the time of Western modernity, knowledge is compartmentalized into differentiated fields. This has however not mitigated the influence of natural science model of theorizing on social sciences. As a result, the discipline of organization theory has grown without the influence of abstract, ephemeral and metaphysical fields such as religion, history, mystic philosophy, arts and literature. With the rise of organizational cultural studies and the emergence of symbolic-interpretive view of organizing during the last three or four decades, the trend is however gradually shifting. Corporate aesthetics is a field within organization theory which places value on the aesthetical aspects of managing and organizing. Taking the lead from corporate aesthetics, this paper highlights the link between Organization theory and literature (poetry, both English and Urdu. The linguistic and conceptual instrument of metaphors is isolated as the underpinning tool of this link. The role of metaphors in organization theory seems to have further importance because of the emergence of „social construction‟ and „sense making‟ views of organizations. The paper reinforces the views of contemporary writers of organization theory that the field draws from multiple and diverse disciplines by highlighting the link between organization theory and poetry through employing metaphoricity.

  16. Modeling Heterogeneity in Direct Infectious Disease Transmission in a Compartmental Model.

    Science.gov (United States)

    Kong, Lingcai; Wang, Jinfeng; Han, Weiguo; Cao, Zhidong

    2016-03-01

    Mathematical models have been used to understand the transmission dynamics of infectious diseases and to assess the impact of intervention strategies. Traditional mathematical models usually assume a homogeneous mixing in the population, which is rarely the case in reality. Here, we construct a new transmission function by using as the probability density function a negative binomial distribution, and we develop a compartmental model using it to model the heterogeneity of contact rates in the population. We explore the transmission dynamics of the developed model using numerical simulations with different parameter settings, which characterize different levels of heterogeneity. The results show that when the reproductive number, R₀, is larger than one, a low level of heterogeneity results in dynamics similar to those predicted by the homogeneous mixing model. As the level of heterogeneity increases, the dynamics become more different. As a test case, we calibrated the model with the case incidence data for severe acute respiratory syndrome (SARS) in Beijing in 2003, and the estimated parameters demonstrated the effectiveness of the control measures taken during that period. PMID:26927140

  17. Modeling Heterogeneity in Direct Infectious Disease Transmission in a Compartmental Model

    Directory of Open Access Journals (Sweden)

    Lingcai Kong

    2016-02-01

    Full Text Available Mathematical models have been used to understand the transmission dynamics of infectious diseases and to assess the impact of intervention strategies. Traditional mathematical models usually assume a homogeneous mixing in the population, which is rarely the case in reality. Here, we construct a new transmission function by using as the probability density function a negative binomial distribution, and we develop a compartmental model using it to model the heterogeneity of contact rates in the population. We explore the transmission dynamics of the developed model using numerical simulations with different parameter settings, which characterize different levels of heterogeneity. The results show that when the reproductive number, R0, is larger than one, a low level of heterogeneity results in dynamics similar to those predicted by the homogeneous mixing model. As the level of heterogeneity increases, the dynamics become more different. As a test case, we calibrated the model with the case incidence data for severe acute respiratory syndrome (SARS in Beijing in 2003, and the estimated parameters demonstrated the effectiveness of the control measures taken during that period.

  18. Reservoir compartmentalization and management strategies: Lessons learned in the Illinois basin

    Energy Technology Data Exchange (ETDEWEB)

    Grube, J.P.; Crockett, J.E.; Huff, B.G. [and others

    1997-08-01

    A research project jointly sponsored by the US Department of Energy and the Illinois State Geological Survey focused on the Cypress and Aux Vases Formations (Mississippian), major clastic reservoirs in the Illinois Basin. Results from the research showed that understanding the nature and distribution of reservoir compartments, and using effective reservoir management strategies, can significantly improve recovery efficiencies from oil fields in this mature basin. Compartments can be most effectively drained where they are geologically well defined and reservoir management practices are coordinated through unified, compartment-wide, development programs. Our studies showed that the Cypress and Aux Vases reservoirs contain lateral and vertical permeability barriers forming compartments that range in size from isolated, interlaminated sandstone and shale beds to sandstone bodies tens of feet in thickness and more than a mile in length. Stacked or shingled, genetically similar sandstone bodies are commonly separated by thin impermeable intervals that can be difficult to distinguish on logs and can, therefore, cause correlation problems, even between wells drilled on spacing of less than ten acres. Lateral separation of sandstone bodies causes similar problems. Reservoir compartmentalization reduces primary and particularly secondary recovery by trapping pockets of by-passed or banked oil. Compartments can be detected by comparing recovery factors of genetically similar sandstone bodies within a field; using packers to separate commingled intervals and analyzing fluid recoveries and pressures; making detailed core-to-log calibrations that identify compartment boundaries; and analyzing pressure data from waterflood programs.

  19. A multi-stage compartmental model for HIV-infected individuals: I--waiting time approach.

    Science.gov (United States)

    Billard, L; Dayananda, P W A

    2014-03-01

    Traditionally, epidemic processes have focused on establishing systems of differential-difference equations governing the number of individuals at each stage of the epidemic. Except for simple situations such as when transition rates are linear, these equations are notoriously intractable mathematically. In this work, the process is described as a compartmental model. The model also allows for individuals to go directly from any prior compartment directly to a final stage corresponding to death. This allows for the possibility that individuals can die earlier due to some non-disease related cause. Then, the model is based on waiting times in each compartment. Survival probabilities of moving from a given compartment to another compartment are established. While our approach can be used for general epidemic processes, our framework is for the HIV/AIDS process. It is then possible to establish the impact of the HIV/AIDS epidemic process on, e.g., insurance premiums and payouts and health-care costs. The effect of changing model parameter values on these entities is investigated.

  20. Compartmental analysis and dosimetric aspects applied to cholesterol with 3H labeled

    International Nuclear Information System (INIS)

    Cardiovascular diseases (CVDs) are one of the major reasons of death around the world according to the World Health Organization (WHO). It is well known that changes in levels of plasma lipoproteins, which are responsible for the transport of cholesterol into the bloodstream, are associated with cardiovascular diseases. For this reason to know the biokinetic parameters of plasma lipoproteins and quantifies them is important to correct and deep understanding about the diseases associated with these disorders. The main aim of this study is to provide a biokinetic model and estimate the radiometric doses for 3H-Cholesterol, a radioactive tracer widely used in physiological and metabolic studies. The model was based on [Schwartz et al. 2004] about the distribution of cholesterol by the lipoprotein and gastrointestinal model [ICRP 30, 1979]. The doses distribution in compartments of the model and other organs and tissues of a standard adult described in [ICRP 106, 2008] was calculated using MIRD method (Medical Internal Radiation Dose) and compartmental analysis using the computer program Matlab®. The dose coefficients were estimated for a standard phantom man (73 kg) described in [ICRP 60, 1991]. The estimated doses for both model and for other organs were low and did not exceed the highest dose obtained that was in the upper large intestine, as 44,8 μGy these parameters will assist in ethics committee's opinions on the use of works that use the 3H-cholesterol which radioactive tracer. (author)

  1. Convex-Optimization-Based Compartmental Pharmacokinetic Analysis for Prostate Tumor Characterization Using DCE-MRI.

    Science.gov (United States)

    Ambikapathi, ArulMurugan; Chan, Tsung-Han; Lin, Chia-Hsiang; Yang, Fei-Shih; Chi, Chong-Yung; Wang, Yue

    2016-04-01

    Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a powerful imaging modality to study the pharmacokinetics in a suspected cancer/tumor tissue. The pharmacokinetic (PK) analysis of prostate cancer includes the estimation of time activity curves (TACs), and thereby, the corresponding kinetic parameters (KPs), and plays a pivotal role in diagnosis and prognosis of prostate cancer. In this paper, we endeavor to develop a blind source separation algorithm, namely convex-optimization-based KPs estimation (COKE) algorithm for PK analysis based on compartmental modeling of DCE-MRI data, for effective prostate tumor detection and its quantification. The COKE algorithm first identifies the best three representative pixels in the DCE-MRI data, corresponding to the plasma, fast-flow, and slow-flow TACs, respectively. The estimation accuracy of the flux rate constants (FRCs) of the fast-flow and slow-flow TACs directly affects the estimation accuracy of the KPs that provide the cancer and normal tissue distribution maps in the prostate region. The COKE algorithm wisely exploits the matrix structure (Toeplitz, lower triangular, and exponential decay) of the original nonconvex FRCs estimation problem, and reformulates it into two convex optimization problems that can reliably estimate the FRCs. After estimation of the FRCs, the KPs can be effectively estimated by solving a pixel-wise constrained curve-fitting (convex) problem. Simulation results demonstrate the efficacy of the proposed COKE algorithm. The COKE algorithm is also evaluated with DCE-MRI data of four different patients with prostate cancer and the obtained results are consistent with clinical observations.

  2. A compartmental model to describe hydraulics in a full-scale waste stabilization pond.

    Science.gov (United States)

    Alvarado, Andres; Vedantam, Sreepriya; Goethals, Peter; Nopens, Ingmar

    2012-02-01

    The advancement of experimental and computational resources has facilitated the use of computational fluid dynamics (CFD) models as a predictive tool for mixing behaviour in full-scale waste stabilization pond systems. However, in view of combining hydraulic behaviour with a biokinetic process model, the computational load is still too high for practical use. This contribution presents a method that uses a validated CFD model with tracer experiments as a platform for the development of a simpler compartmental model (CM) to describe the hydraulics in a full-scale maturation pond (7 ha) of a waste stabilization ponds complex in Cuenca (Ecuador). 3D CFD models were validated with experimental data from pulse tracer experiments, showing a sufficient agreement. Based on the CFD model results, a number of compartments were selected considering the turbulence characteristics of the flow, the residence time distribution (RTD) curves and the dominant velocity component at different pond locations. The arrangement of compartments based on the introduction of recirculation flow rate between adjacent compartments, which in turn is dependent on the turbulence diffusion coefficient, is illustrated. Simulated RTD's from a systemic tanks-in-series (TIS) model and the developed CM were compared. The TIS was unable to capture the measured RTD, whereas the CM predicted convincingly the peaks and lags of the tracer experiment using only a minimal fraction of the computational demand of the CFD model. Finally, a biokinetic model was coupled to both approaches demonstrating the impact an insufficient hydraulic model can have on the outcome of a modelling exercise. TIS and CM showed drastic differences in the output loads implying that the CM approach is to be used when modelling the biological performance of the full-scale system. PMID:22137448

  3. Comparison of total and compartmental gastric emptying and antral motility between healthy men and women

    Energy Technology Data Exchange (ETDEWEB)

    Bennink, R.; Van den Maegdenbergh, V.; Roo, M. de; Mortelmans, L. [Department of Nuclear Medicine, UZ KU Leuven (Belgium); Peeters, M.; Geypens, B.; Rutgeerts, P. [Department of Gastroenterology, UZ KU Leuven (Belgium)

    1998-09-01

    There is increasing evidence of gender-related differences in gastric emptying. The purpose of this study was first, to confirm the difference in gastric emptying for both solid and liquid test meals between healthy men and women, and secondly, to investigate the origin of this difference by studying regional gastric emptying and antral motility. A standard gastric emptying test with additional compartmental (proximal and distal) evaluation and dynamic imaging of the antrum was performed in 20 healthy women studied during the first 10 days of the menstrual cycle, and in 31 healthy age-matched men. In concordance with previous reports, women had a longer half-emptying time for solids as compared to men (86.2{+-}5.1 vs 52.2{+-}2.9 min, P<0.05). In our observations this seemed to be related to a significantly prolonged lag phase and a significant decrease in terminal slope. Dynamical antral scintigraphy did not show a significant difference. The distribution of the test meal within the stomach (proximal vs distal) showed more early proximal retention in women as compared to men. The terminal slope of the distal somach was significantly lower in women. We did not observe a significant difference in gastric emptying of the liquid test meal between men and women. Gastric emptying of solids is significantly slower in healthy women as compared to men. These findings emphasise the importance of using different normal values for clinical and research purposes in gastric emptying scintigraphy in men and women. The difference could not be explained by antral motility alone. Increased proximal retention and a lower terminal emptying rate in women are observations to be further investigated. (orig.) With 5 figs., 2 tabs., 36 refs.

  4. Biodistribution and biological characteristics of p-[(bis-carboxymethyl) aminomethyl carboxyamino] hippuric acid (Pahida) labelled with technetium-99m. Establishment of pharmacokinetics parameters through compartmental model

    International Nuclear Information System (INIS)

    Biologic distribution of p- [(bis-carboxymethylaminomethyl carboxyamino)] hippuric acid (PAHIDA) labeled with sup(99m)Tc in Wistar rats, showed a selective renal uptake among the other organs and tissues. The compound is predominantly eliminated by urinary tract, with small enterohepatic percent of excretion Chromatographic analysis of urine showed the product and possible metabolites. PAHIDA- sup(99m)Tc blood clearance is relatively rapid and a good percent is transported by plasmatic proteins. The percent binding to the erythrocytes is significant after one hour, this is due probably to hydrolysed technetium. The extrapolation of the plasmatic curve denoted the existence of three exponentials, suggesting a model with three compartments: central or intravascular and two peripherics or extravasculars - rapid and slow exchange (retention). Exponential's half life and the transfer constant (k) among the compartments were determined. The compound retention was reaffirmed by whole body determination. The decomposition of the curve in two exponentials allowed to assess the component's half-life. The compartmental model proposed in agreement with the experimental results, showed the complex retention that may be related the binding with the blood components, the possibility of renal metabolization or a structural impediment in the interaction with the tubular cells receptors. (author)

  5. Multilevel selection in models of prebiotic evolution II: a direct comparison of compartmentalization and spatial self-organization.

    Directory of Open Access Journals (Sweden)

    Nobuto Takeuchi

    2009-10-01

    Full Text Available Multilevel selection has been indicated as an essential factor for the evolution of complexity in interacting RNA-like replicator systems. There are two types of multilevel selection mechanisms: implicit and explicit. For implicit multilevel selection, spatial self-organization of replicator populations has been suggested, which leads to higher level selection among emergent mesoscopic spatial patterns (traveling waves. For explicit multilevel selection, compartmentalization of replicators by vesicles has been suggested, which leads to higher level evolutionary dynamics among explicitly imposed mesoscopic entities (protocells. Historically, these mechanisms have been given separate consideration for the interests on its own. Here, we make a direct comparison between spatial self-organization and compartmentalization in simulated RNA-like replicator systems. Firstly, we show that both mechanisms achieve the macroscopic stability of a replicator system through the evolutionary dynamics on mesoscopic entities that counteract that of microscopic entities. Secondly, we show that a striking difference exists between the two mechanisms regarding their possible influence on the long-term evolutionary dynamics, which happens under an emergent trade-off situation arising from the multilevel selection. The difference is explained in terms of the difference in the stability between self-organized mesoscopic entities and externally imposed mesoscopic entities. Thirdly, we show that a sharp transition happens in the long-term evolutionary dynamics of the compartmentalized system as a function of replicator mutation rate. Fourthly, the results imply that spatial self-organization can allow the evolution of stable folding in parasitic replicators without any specific functionality in the folding itself. Finally, the results are discussed in relation to the experimental synthesis of chemical Darwinian systems and to the multilevel selection theory of

  6. Does location of patellofemoral chondral lesion influence outcome after Oxford medial compartmental knee arthroplasty?

    Science.gov (United States)

    Konan, S.; Haddad, F. S.

    2016-01-01

    Aims Medial unicompartmental knee arthroplasty (UKA) is associated with successful outcomes in carefully selected patient cohorts. We hypothesised that severity and location of patellofemoral cartilage lesions significantly influences functional outcome after Oxford medial compartmental knee arthroplasty. Patients and Methods We reviewed 100 consecutive UKAs at minimum eight-year follow-up (96 to 132). A single surgeon performed all procedures. Patients were selected based on clinical and plain radiographic assessment. All patients had end-stage medial compartment osteoarthritis (OA) with sparing of the lateral compartment and intact anterior cruciate ligaments. None of the patients had end-stage patellofemoral OA, but patients with anterior knee pain or partial thickness chondral loss were not excluded. There were 57 male and 43 female patients. The mean age at surgery was 69 years (41 to 82). At surgery the joint was carefully inspected for patellofemoral chondral loss and this was documented based on severity of cartilage loss (0 to 4 Outerbridge grading) and topographic location (medial, lateral, central, and superior or inferior). Functional scores collected included Oxford Knee Score (OKS), patient satisfaction scale and University College Hospital (UCH) knee score. Intraclass correlation was used to compare chondral damage to outcomes. Results All patients documented significant improvement in pain and improved functional scores at mid-term follow-up. There were four revisions (mean 2.9 years, 2 to 4; standard deviation (sd) 0.9) in this cohort, three for tibial loosening and one for femoral loosening. There was one infection that was treated with debridement and insert exchange. The mean OKS improved from 23.2 (sd 7.1) to 39.1 (sd 6.9); p < 0.001. The cohort with central and lateral grade 3 patellofemoral OA documented lower mean satisfaction with pain (90, sd 11.8) and function (87.5, sd 10.3) on the patient satisfaction scale. On the UCH scale, patients

  7. Structural localization and origin of compartmentalized fluid flow, Comstock lode, Virginia City, Nevada

    Science.gov (United States)

    Berger, B.R.; Tingley, J.V.; Drew, L.J.

    2003-01-01

    Bonanza-grade orebodies in epithermal-style mineral deposits characteristically occur as discrete zones within spatially more extensive fault and/or fracture systems. Empirically, the segregation of such systems into compartments of higher and lower permeability appears to be a key process necessary for high-grade ore formation and, most commonly, it is such concentrations of metals that make an epithermal vein district world class. In the world-class silver- and gold-producing Comstock mining district, Nevada, several lines of evidence lead to the conclusion that the Comstock lode is localized in an extensional stepover between right-lateral fault zones. This evidence includes fault geometries, kinematic indicators of slip, the hydraulic connectivity of faults as demonstrated by veins and dikes along faults, and the opening of a normal-fault-bounded, asymmetric basin between two parallel and overlapping northwest-striking, lateral- to lateral-oblique-slip fault zones. During basin opening, thick, generally subeconomic, banded quartz-adularia veins were deposited in the normal fault zone, the Comstock fault, and along one of the bounding lateral fault zones, the Silver City fault. As deformation continued, the intrusion of dikes and small plugs into the hanging wall of the Comstock fault zone may have impeded the ability of the stepover to accommodate displacement on the bounding strike-slip faults through extension within the stepover. A transient period of transpressional deformation of the Comstock fault zone ensued, and the early-stage veins were deformed through boudinaging and hydraulic fragmentation, fault-motion inversion, and high- and low-angle axial rotations of segments of the fault planes and some fault-bounded wedges. This deformation led to the formation of spatially restricted compartments of high vertical permeability and hydraulic connectivity and low lateral hydraulic connectivity. Bonanza orebodies were formed in the compartmentalized zones of

  8. Compartmentalization of the precheliceral neuroectoderm in the spider Cupiennius salei: development of the arcuate body, optic ganglia, and mushroom body.

    Science.gov (United States)

    Doeffinger, Carola; Hartenstein, Volker; Stollewerk, Angelika

    2010-07-01

    Similarly to vertebrates, arthropod brains are compartmentalized into centers with specific neurological functions such as cognition, behavior, and memory. The centers can be further subdivided into smaller functional units. This raises the question of how these compartments are formed during development and how they are integrated into brain centers. We show here for the first time how the precheliceral neuroectoderm of the spider Cupiennius salei is compartmentalized to form the distinct brain centers of the visual system: the optic ganglia, the mushroom bodies, and the arcuate body. The areas of the visual brain centers are defined by the formation of grooves and vesicles and express the proneural gene CsASH1, followed by expression of the neural differentiation marker Prospero. Furthermore, the transcription factor dachshund, which is strongly enriched in the mushroom bodies and the outer optic ganglion of Drosophila, is expressed in the optic anlagen and the mushroom bodies of the spider. The developing brain centers are further subdivided into single neural precursor groups, which become incorporated into the grooves and vesicles but remain distinguishable throughout development, suggesting that they encode spatial information for neural subtype identity. Several molecular and morphological aspects of the development of the optic ganglia and the mushroom bodies are similar in the spider and in insects. Furthermore, we show that the primary engrailed head spot contributes neurons to the optic ganglia of the median eyes, whereas the secondary head spot, which has been associated with the optic ganglia in insects and crustaceans, is absent. PMID:20503430

  9. Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: Implications for a regional risk assessment

    International Nuclear Information System (INIS)

    The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air–water flux, including air–water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air–water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. - Highlights: • Transport fluxes of chlorpyrifos and pyrethroids were assessed in Guangzhou, China. • Sediment acted as a sink for chlorpyrifos and pyrethroids. • Air-to-water transport decreased the exposure risk of atmospheric chlorpyrifos. • Dynamic transport might increase the risk of pyrethroids in air and sediment. • Flux-based pesticide concentrations provide a way to estimate sediment toxicity. - Regional risk assessment could be improved by integrating dynamic flux information derived from inter-compartmental models

  10. Use of transfer function and compartmental analysis to quantify 11C-labelled photoassimilate export from wheat leaves

    International Nuclear Information System (INIS)

    Compartmental analysis of tracer loss from a leaf after pulse-labelling with carbon isotopes has often been used to infer the flow of photosynthate through the leaf. Recently, a more general approach has been suggested based upon estimation of the transfer function using data from pulse-labelling as well as continuous labelling experiments. A comparison of these two approaches shows that with the same data set they give equivalent physiological interpretations. The measured decline of 11C activity from a wheat leaf after 11CO2 pulse-labelling was extrapolated by compartmental as well as transfer function analysis. Both methods estimated a 66.4% loss of the initially fixed 11C due to export and respiration. The advantage of transfer function analysis, however, is its applicability to continuous-labelling experiments. The model allows the use of the net photosynthetic rate as the reference (100%) value. Data from continuous-labelling experiments with wheat plants indicate diurnal variations in the export of freshly labelled assimilate of between 32.7% and 43.6% of net photosynthesis. (author)

  11. Multi-hollow polymer microspheres with enclosed surfaces and compartmentalized voids prepared by seeded swelling polymerization method.

    Science.gov (United States)

    Tian, Qiong; Yu, Demei; Zhu, Kaiming; Hu, Guohe; Zhang, Lifeng; Liu, Yuhang

    2016-07-01

    Multi-hollow particles have drawn extensive research interest due to their high specific areas and abundant inner voids, whereas their convenient synthesis still remains challenging. In this paper, we report a simple and convenient method based on seeded swelling polymerization to prepare the multi-hollow microspheres with enclosed surfaces and compartmentalized voids using monodisperse poly (styrene-co-sodium 4-vinylbenzenesulfonate) microspheres as seed particles. A formation mechanism of the multi-hollow structure was proposed involving the processes of water absorption, coalescence and stabilization of water domains, immobilization of multi-hollow structure, and coverage of surface dimples. The influencing parameters on the morphology of the microspheres, including weight ratio of sodium 4-vinylbenzenesulfonate to styrene in the seed particles, dosage of the swelling monomer and the crosslinking agent were systematically investigated. The internal structure of the resultant microspheres could be tuned from solid to multi-hollow by controlling over these parameters. Multi-hollow microspheres with compartmentalized chambers, smooth surfaces and narrow size distributions were obtained as a result. PMID:27046772

  12. Cs-137 accumulation and elimination by Gracilaria caudata alga and Abudefduf saxatilis fish. Compartmental analysis; Acumulo e eliminacao de Cs-137 pela alga Gracilaria caudata e peixe Abudefduf saxatilis. Modelo compartimental

    Energy Technology Data Exchange (ETDEWEB)

    Mattiolo-Marchese, Sandra Regina

    1998-07-01

    From the ecological point of view, {sup 137}Cs is a critical radionuclide because its physical half-life is long (30 years), and it has a high fission yield. Besides, it presents similar characteristics to sodium and potassium, fundamental elements for the living organisms, in great concentration in all cells. This work has as aim to study the {sup 137}Cs accumulation and elimination by the alga Gracilaria caudata and by the fish Abudefduf saxatilis as well as to obtain the transfer constants of the{sup 137}Cs from the water into the organisms. The concentration factor found for the fish was 5.6 +- 0.2 and for the alga, 13.0 +- 0,6. With 7 and 22 days, the fish and alga respectively had already eliminated half of the accumulated radionuclide. The {sup 137}Cs ingestion efficiency by the fish was also studied and it was verified that the fish assimilated only 47.6 % of the cesium content in the food; and within of 4 days it had eliminated more than half of ingested cesium. A compartmental model was proposed to explain the distribution of cesium in the compartments (water - alga and water - fish). Data obtained from the experiments of {sup 137}Cs accumulation and elimination were applied in the Ana Comp Program. This program permits the compartmental analysis, and quantifies the cesium distribution from the sea-water to the organisms, and vice versa, through the transfer constants (k). The Ana Comp Program also allowed to calculate the dose that one would receive by the consumption of fish contaminated by cesium. Levels of {sup 137}Cs from the global fallout in environmental samples, from Sao Sebastiao, northern coast of Sao Paulo, (where the 'Centro de Biologia Marinha da Universidade de Sao Paulo - CEBIMar - USP' is located), were verified. (author)

  13. Complex-shaped three-dimensional multi-compartmental microparticles generated by diffusional and Marangoni microflows in centrifugally discharged droplets

    Science.gov (United States)

    Hayakawa, Masayuki; Onoe, Hiroaki; Nagai, Ken H.; Takinoue, Masahiro

    2016-02-01

    We report a versatile method for the generation of complex-shaped three-dimensional multi-compartmental (3D-MC) microparticles. Complex-shaped microparticles have recently received much attention for potential application in self-assemblies, micromachines, and biomedical and environmental engineering. Here, we have developed a method based on 3D nonequilibrium-induced microflows (Marangoni and diffusional flows) of microdroplets that are discharged from the tip of a thin capillary in a simple centrifugal microfluidic device. The microparticle shapes can be tuned by the partial dissolution of specific compartments and by the deformation of the precursor microdroplets by manipulating the 3D microflows. We believe that this method will have wide applications in nano- and microscience and technologies.

  14. Effect of compartmentalization of donor and acceptor on the ultrafast resonance energy transfer from DAPI to silver nanoclusters

    Science.gov (United States)

    Prajapati, Roopali; Chatterjee, Surajit; Kannaujiya, Krishna K.; Mukherjee, Tushar Kanti

    2016-06-01

    The mechanism and dynamics of excitation energy transfer (EET) from photo-excited 4',6-diamidino-2-phenylindole (DAPI) to silver nanoclusters (Ag NCs) and its subsequent modulation in the presence of cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) and Calf Thymus DNA (CT-DNA) have been demonstrated using steady-state fluorescence and femtosecond fluorescence upconversion techniques. The synthesized Ag NCs were characterized using FTIR, mass spectrometry, XPS, HRTEM, DLS, UV-Vis and PL spectroscopy. Mass spectrometric analysis reveals the formation of ultrasmall Ag4 NCs with a small amount of Ag5 NCs. UV-Vis and PL spectra reveal distinct molecular-like optoelectronic behaviour of these ultrasmall Ag NCs. The dihydrolipoic acid-capped Ag NCs strongly quench the fluorescence of DAPI with concomitant increase in its photoluminescence (PL) intensity at 675 nm. This steady-state fluorescence quenching proceeds with a significant shortening of the fluorescence lifetime of DAPI in the presence of Ag NCs, signifying the nonradiative Förster resonance energy transfer (FRET) from DAPI to Ag NCs. Various energy transfer parameters have been estimated from FRET theory. The present FRET pair shows a characteristic Förster distance of 2.45 nm and can be utilized as a reporter of short-range distances in various FRET based applications. Moreover, this nonradiative FRET is completely suppressed in the presence of both 0.2 wt% PDADMAC and CT-DNA. Our results reveal selective compartmentalization of Ag NCs and DAPI in the presence of 0.2 wt% PDADMAC and CT-DNA, respectively. This selective compartmentalization of donor and acceptor and the subsequent modification of the FRET process may find application in various sensing, photovoltaic, and light harvesting applications.The mechanism and dynamics of excitation energy transfer (EET) from photo-excited 4',6-diamidino-2-phenylindole (DAPI) to silver nanoclusters (Ag NCs) and its subsequent modulation in the presence

  15. Effect of compartmentalization of donor and acceptor on the ultrafast resonance energy transfer from DAPI to silver nanoclusters.

    Science.gov (United States)

    Prajapati, Roopali; Chatterjee, Surajit; Kannaujiya, Krishna K; Mukherjee, Tushar Kanti

    2016-07-14

    The mechanism and dynamics of excitation energy transfer (EET) from photo-excited 4',6-diamidino-2-phenylindole (DAPI) to silver nanoclusters (Ag NCs) and its subsequent modulation in the presence of cationic polymer poly(diallyldimethylammonium chloride) (PDADMAC) and Calf Thymus DNA (CT-DNA) have been demonstrated using steady-state fluorescence and femtosecond fluorescence upconversion techniques. The synthesized Ag NCs were characterized using FTIR, mass spectrometry, XPS, HRTEM, DLS, UV-Vis and PL spectroscopy. Mass spectrometric analysis reveals the formation of ultrasmall Ag4 NCs with a small amount of Ag5 NCs. UV-Vis and PL spectra reveal distinct molecular-like optoelectronic behaviour of these ultrasmall Ag NCs. The dihydrolipoic acid-capped Ag NCs strongly quench the fluorescence of DAPI with concomitant increase in its photoluminescence (PL) intensity at 675 nm. This steady-state fluorescence quenching proceeds with a significant shortening of the fluorescence lifetime of DAPI in the presence of Ag NCs, signifying the nonradiative Förster resonance energy transfer (FRET) from DAPI to Ag NCs. Various energy transfer parameters have been estimated from FRET theory. The present FRET pair shows a characteristic Förster distance of 2.45 nm and can be utilized as a reporter of short-range distances in various FRET based applications. Moreover, this nonradiative FRET is completely suppressed in the presence of both 0.2 wt% PDADMAC and CT-DNA. Our results reveal selective compartmentalization of Ag NCs and DAPI in the presence of 0.2 wt% PDADMAC and CT-DNA, respectively. This selective compartmentalization of donor and acceptor and the subsequent modification of the FRET process may find application in various sensing, photovoltaic, and light harvesting applications. PMID:27304093

  16. Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae.

    Science.gov (United States)

    Kemsawasd, Varongsiri; Branco, Patrícia; Almeida, Maria Gabriela; Caldeira, Jorge; Albergaria, Helena; Arneborg, Nils

    2015-07-01

    The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides.

  17. Multicellular compartmentation of catharanthus roseus alkaloid biosynthesis predicts intercellular translocation of a pathway intermediate

    Science.gov (United States)

    St-Pierre, B; Vazquez-Flota, FA; De Luca V

    1999-01-01

    In situ RNA hybridization and immunocytochemistry were used to establish the cellular distribution of monoterpenoid indole alkaloid biosynthesis in Madagascar periwinkle (Catharanthus roseus). Tryptophan decarboxylase (TDC) and strictosidine synthase (STR1), which are involved in the biosynthesis of the central intermediate strictosidine, and desacetoxyvindoline 4-hydroxylase (D4H) and deacetylvindoline 4-O-acetyltransferase (DAT), which are involved in the terminal steps of vindoline biosynthesis, were localized. tdc and str1 mRNAs were present in the epidermis of stems, leaves, and flower buds, whereas they appeared in most protoderm and cortical cells around the apical meristem of root tips. In marked contrast, d4h and dat mRNAs were associated with the laticifer and idioblast cells of leaves, stems, and flower buds. Immunocytochemical localization for TDC, D4H, and DAT proteins confirmed the differential localization of early and late stages of vindoline biosynthesis. Therefore, we concluded that the elaboration of the major leaf alkaloids involves the participation of at least two cell types and requires the intercellular translocation of a pathway intermediate. A basipetal gradient of expression in maturing leaves also was shown for all four genes by in situ RNA hybridization studies and by complementary studies with dissected leaves, suggesting that expression of the vindoline pathway occurs transiently during early leaf development. These results partially explain why attempts to produce vindoline by cell culture technology have failed. PMID:10330473

  18. Follicle-restricted compartmentalization of transforming growth factor beta superfamily ligands in the feline ovary.

    Science.gov (United States)

    Bristol, Sarah K; Woodruff, Teresa K

    2004-03-01

    Ovarian follicular development, follicle selection, and the process of ovulation remain poorly understood in most species. Throughout reproductive life, follicle fate is balanced between growth and apoptosis. These opposing forces are controlled by numerous endocrine, paracrine, and autocrine factors, including the ligands represented by the transforming growth factor beta (TGFbeta) superfamily. TGFbeta, activin, inhibin, bone morphometric protein (BMP), and growth differentiation factor 9 (GDF-9) are present in the ovary of many animals; however, no comprehensive analysis of the localization of each ligand or its receptors and intracellular signaling molecules during folliculogenesis has been done. The domestic cat is an ideal model for studying ovarian follicle dynamics due to an abundance of all follicle populations, including primordial stage, and the amount of readily available tissue following routine animal spaying. Additionally, knowledge of the factors involved in feline follicular development could make an important impact on in vitro maturation/in vitro fertilization (IVM/IVF) success for endangered feline species. Thus, the presence and position of TGFbeta superfamily members within the feline ovary have been evaluated in all stages of follicular development by immunolocalization. The cat inhibin alpha subunit protein is present in all follicle stages but increases in intensity within the mural granulosa cells in large antral follicles. The inhibin betaA and betaB subunit proteins, in addition to the activin type I (ActRIB) and activin type II receptor (ActRIIB), are produced in primordial and primary follicle granulosa cells. Additionally, inhibin betaA subunit is detected in the theca cells from secondary through large antral follicle size classes. GDF-9 is restricted to the oocyte of preantral and antral follicles, whereas the type II BMP receptor (BMP-RII) protein is predominantly localized to primordial- and primary-stage follicles. TGFbeta1, 2

  19. A stromal cell niche for human and mouse type 3 innate lymphoid cells

    OpenAIRE

    Hoorweg, Kerim; Narang, Priyanka; Li, Zhi; Thuery, Anne; Papazian, Natalie; Withers, David R; Coles, Mark C.; Cupedo, Tom

    2015-01-01

    Adaptive immunity critically depends on the functional compartmentalization of secondary lymphoid organs. Mesenchymal stromal cells create and maintain specialized niches that support survival, activation and expansion of T and B cells, and integrated analysis of lymphocytes and their niche has been instrumental in understanding adaptive immunity. Lymphoid organs are also home to type 3 innate lymphoid cells (ILC3), innate effector cells essential for barrier immunity. However, a specialized ...

  20. Human biokinetic data and a new compartmental model of zirconium - A tracer study with enriched stable isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Greiter, Matthias B., E-mail: matthias.greiter@helmholtz-muenchen.de; Giussani, Augusto, E-mail: AGiussani@BfS.de; Hoellriegl, Vera, E-mail: vera.hoellriegl@helmholtz-muenchen.de; Li Weibo, E-mail: wli@helmholtz-muenchen.de; Oeh, Uwe, E-mail: uwe.oeh@helmholtz-muenchen.de

    2011-09-01

    Biokinetic models describing the uptake, distribution and excretion of trace elements are an essential tool in nutrition, toxicology, or internal dosimetry of radionuclides. Zirconium, especially its radioisotope {sup 95}Zr, is relevant to radiation protection due to its production in uranium fission and neutron activation of nuclear fuel cladding material. We present a comprehensive set of human data from a tracer study with stable isotopes of zirconium. The data are used to refine a biokinetic model of zirconium. Six female and seven male healthy adult volunteers participated in the study. It includes 16 complete double tracer investigations with oral ingestion and intravenous injection, and seven supplemental investigations. Tracer concentrations were measured in blood plasma and urine collected up to 100 d after tracer administration. The four data sets (two chemical tracer forms in plasma and urine) each encompass 105-240 measured concentration values above detection limits. Total fractional absorption of ingested zirconium was found to be 0.001 for zirconium in citrate-buffered drinking solution and 0.007 for zirconium oxalate solution. Biokinetic models were developed based on the linear first-order kinetic compartmental model approach used by the International Commission on Radiological Protection (ICRP). The main differences of the optimized systemic model of zirconium to the current ICRP model are (1) recycling into the transfer compartment made necessary by the observed tracer clearance from plasma, (2) different parameters related to fractional absorption for each form of the ingested tracer, and (3) a physiologically based excretion pathway to urine. The study considerably expands the knowledge on the biokinetics of zirconium, which was until now dominated by data from animal studies. The proposed systemic model improves the existing ICRP model, yet is based on the same principles and fits well into the ICRP radiation protection approach. - Research

  1. Subcellular Compartmentalization and Trafficking of the Biosynthetic Machinery for Fungal Melanin

    OpenAIRE

    Srijana Upadhyay; Xinping Xu; David Lowry; Jennifer C. Jackson; Robert W. Roberson; Xiaorong Lin

    2016-01-01

    Protection by melanin depends on its subcellular location. Although most filamentous fungi synthesize melanin via a polyketide synthase pathway, where and how melanin biosynthesis occurs, and how it is deposited as extracellular granules, remain elusive. Using a forward genetic screen in the pathogen Aspergillus fumigatus, we find that mutations in an endosomal sorting nexin abolish melanin cell wall deposition. We find that all enzymes involved in the early steps of melanin biosynthesis are ...

  2. Recombinational DNA repair is regulated by compartmentalization of DNA lesions at the nuclear pore complex

    DEFF Research Database (Denmark)

    Géli, Vincent; Lisby, Michael

    2015-01-01

    The nuclear pore complex (NPC) is emerging as a center for recruitment of a class of "difficult to repair" lesions such as double-strand breaks without a repair template and eroded telomeres in telomerase-deficient cells. In addition to such pathological situations, a recent study by Su and colle...... lesions that relocalize to the NPC, the putative mechanisms of relocalization, and the types of recombinational repair that are stimulated by the NPC, and present a model for NPC-facilitated repair....

  3. Multipotent Capacity of Immortalized Human Bronchial Epithelial Cells

    OpenAIRE

    Delgado, Oliver; Kaisani, Aadil A.; Spinola, Monica; Xie, Xian-Jin; Batten, Kimberly G.; Minna, John D.; Wright, Woodring E; Shay, Jerry W.

    2011-01-01

    While the adult murine lung utilizes multiple compartmentally restricted progenitor cells during homeostasis and repair, much less is known about the progenitor cells from the human lung. Translating the murine stem cell model to humans is hindered by anatomical differences between species. Here we show that human bronchial epithelial cells (HBECs) display characteristics of multipotent stem cells of the lung. These HBECs express markers indicative of several epithelial types of the adult lun...

  4. Visualization of plasma membrane compartmentalization by high-speed quantum dot tracking

    DEFF Research Database (Denmark)

    Clausen, M. P.; Lagerholm, B. C.

    2013-01-01

    In this study, we have imaged plasma membrane molecules labeled with quantum dots in live cells using a conventional wide-field microscope with high spatial precision at sampling frequencies of 1.75 kHz. Many of the resulting single molecule trajectories are sufficiently long (up to several...... thousand steps) to allow for robust single trajectory analysis. This analysis indicates that a majority of the investigated molecules are transiently confined in nanoscopic compartments with a mean size of (100-150 nm)(2) for a mean duration of 50-100 ms....

  5. Acute effects of different inspiratory efforts on ventilatory pattern and chest wall compartmental distribution in elderly women.

    Science.gov (United States)

    Muniz de Souza, Helga; Rocha, Taciano; Campos, Shirley Lima; Brandão, Daniella Cunha; Fink, James B; Aliverti, Andrea; de Andrade, Armele Dornelas

    2016-06-15

    It is not completely described how aging affect ventilatory kinematics and what are the mechanisms adopted by the elderly population to overcome these structural modifications. Given this, the aim was to evaluate the acute effects of different inspiratory efforts on ventilatory pattern and chest wall compartmental distribution in elderly women. Variables assessed included: tidal volume (Vt), total chest wall volume (Vcw), pulmonary rib cage (Vrcp%), abdominal rib cage (Vrca%) and abdominal compartment (Vab%) relative contributions to tidal volume. These variables were assessed during quiet breathing, maximal inspiratory pressure maneuver (MIP), and moderate inspiratory resistance (MIR; i.e., 40% of MIP). 22 young women (age: 23.9±2.5 years) and 22 elderly women (age: 68.2±5.0 years) participated to this study. It was possible to show that during quiet breathing, Vab% was predominant in elderly (p<0.001), in young, however, Vab% was similar to Vrcp% (p=0.095). During MIR, Vrcp% was predominant in young (p<0.001) and comparable to Vab% in elderly (p=0.249). When MIP was imposed, both groups presented a predominance of Vrcp%. In conclusion, there are differences in abdominal kinematics between young and elderly women during different inspiratory efforts. In elderly, during moderate inspiratory resistance, the pattern is beneficial, deep, and slow. Although, during maximal inspiratory resistance, the ventilatory pattern seems to predict imminent muscle fatigue. PMID:26900004

  6. Inter-compartmental transport of organophosphate and pyrethroid pesticides in South China: implications for a regional risk assessment.

    Science.gov (United States)

    Li, Huizhen; Wei, Yanli; Lydy, Michael J; You, Jing

    2014-07-01

    The dynamic flux of an organophosphate and four pyrethroid pesticides was determined in an air-(soil)-water-sediment system based on monitoring data from Guangzhou, China. The total air-water flux, including air-water gaseous exchange and atmospheric deposition, showed deposition from air to water for chlorpyrifos, bifenthrin and cypermethrin, but volatilization for lambda-cyhalothrin and permethrin. The transport of the pesticides from overlying water to sediment suggested that sediment acted as a sink for the pesticides. Additionally, distinct annual atmospheric depositional fluxes between legacy and current-use pesticides suggested the role of consumer usage in their transport throughout the system. Finally, pesticide toxicity was estimated from annual air-water-sediment flux within an urban stream in Guangzhou. A dynamic flux-based risk assessment indicated that inter-compartmental transport of chlorpyrifos decreased its atmospheric exposure, but had little influence on its aquatic toxicity. Instead, water-to-sediment transport of pyrethroids increased their sediment toxicity, which was supported by previously reported toxicity data. PMID:24704807

  7. Levels, spatial variation and compartmentalization of trace elements in brown algae Cystoseira from marine protected areas of Crimea (Black Sea)

    International Nuclear Information System (INIS)

    Highlights: • 19 trace elements were determined in Cystoseira spp. from marine protected areas. • Levels of 10 elements were lower than reported data for Black Sea Cystoseira spp. • Concentrations of most trace elements were higher in “branches” than in “stems”. • Spatial variations of V, Co, Ni and Zn can be related to anthropogenic activities. • Al, Sc, Fe, Rb, Cs, Th, U varied depending on geological composition of the coast. - Abstract: Levels of Al, Sc, V, Co, Ni, As, Br, Rb, Sr, Ag, Sb, I, Cs, Ba, Th and U that were rarely or never studied, as well as the concentrations of classically investigated Mn, Fe and Zn in brown algae Cystoseira barbata C. Ag. and Cystoseira crinita (Desf.) Bory from the coastal waters of marine protected areas (Crimea, Black Sea), were determined using neutron activation analysis. Spatial variation and compartmentalization were studied for all 19 trace elements (TE). Concentrations of most TE were higher in “branches” than in “stems”. Spatial variations of V, Co, Ni and Zn can be related to anthropogenic activities while Al, Sc, Fe, Rb, Cs, Th and U varied depending on chemical peculiarities of the coastal zone rocks. TE concentrations in C. crinita from marine protected areas near Tarkhankut peninsula and Cape Fiolent, identified as the most clean water areas, are submitted as the background concentrations

  8. Substrate uptake and subcellular compartmentation of anoxic cholesterol catabolism in Sterolibacterium denitrificans.

    Science.gov (United States)

    Lin, Ching-Wen; Wang, Po-Hsiang; Ismail, Wael; Tsai, Yu-Wen; El Nayal, Ashraf; Yang, Chia-Ying; Yang, Fu-Chun; Wang, Chia-Hsiang; Chiang, Yin-Ru

    2015-01-01

    Cholesterol catabolism by actinobacteria has been extensively studied. In contrast, the uptake and catabolism of cholesterol by Gram-negative species are poorly understood. Here, we investigated microbial cholesterol catabolism at the subcellular level. (13)C metabolomic analysis revealed that anaerobically grown Sterolibacterium denitrificans, a β-proteobacterium, adopts an oxygenase-independent pathway to degrade cholesterol. S. denitrificans cells did not produce biosurfactants upon growth on cholesterol and exhibited high cell surface hydrophobicity. Moreover, S. denitrificans did not produce extracellular catabolic enzymes to transform cholesterol. Accordingly, S. denitrificans accessed cholesterol by direction adhesion. Cholesterol is imported through the outer membrane via a putative FadL-like transport system, which is induced by neutral sterols. The outer membrane steroid transporter is able to selectively import various C27 sterols into the periplasm. S. denitrificans spheroplasts exhibited a significantly higher efficiency in cholest-4-en-3-one-26-oic acid uptake than in cholesterol uptake. We separated S. denitrificans proteins into four fractions, namely the outer membrane, periplasm, inner membrane, and cytoplasm, and we observed the individual catabolic reactions within them. Our data indicated that, in the periplasm, various periplasmic and peripheral membrane enzymes transform cholesterol into cholest-4-en-3-one-26-oic acid. The C27 acidic steroid is then transported into the cytoplasm, in which side-chain degradation and the subsequent sterane cleavage occur. This study sheds light into microbial cholesterol metabolism under anoxic conditions.

  9. Adequacy of compartmental model for positron emission tomography examinations; Adequacao de modelo compartimental para exames de tomografia por emissao de positrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joao Eduardo Maeda Moreira da; Furuie, Sergio Shiguemi [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia de Telecomunicacoes e Controle. Lab. de Engenharia Biomedica

    2011-12-15

    The objective of this work is the determination of the most adequate compartmental model for the study of physiological dynamics based on positron emission tomography exams. We propose the use of Akaike's information criterion for the optimal model selection, and Levenberg-Marquardt algorithm with sensitivity equations for the task of estimating the characteristic parameters of the differential equations describing the models. We have considered three compartmental structures represented, respectively, by two compartments and two characteristic constants, three compartments and four characteristic constants and four compartments and six characteristics constants. The data considered in this work were synthesized taking into account key features of a real tomography exam, such as type and level of noise and morphology of the input function of the system. Applying the proposed methodology with three noise levels (low, medium and high), we obtained agreement of the best model with strong and considerable degrees (with Kappa indexes equal to 0.95, 0.93 and 0.63, respectively). It was observed that, with high noise level and more complex models (four compartments), the classification is deteriorated due to lack of data for the decision. Programs have been developed and a graphical interface that can be used in research, development, simulation and parameter identification of compartmental models, supporting analysis of clinical diagnostics and scientific practices. (author)

  10. Is the Dissociative Experiences Scale able to identify detachment and compartmentalization symptoms? Factor structure of the Dissociative Experiences Scale in a large sample of psychiatric and nonpsychiatric subjects

    Science.gov (United States)

    Mazzotti, Eva; Farina, Benedetto; Imperatori, Claudio; Mansutti, Federica; Prunetti, Elena; Speranza, Anna Maria; Barbaranelli, Claudio

    2016-01-01

    Background In this study, we explored the ability of the Dissociative Experiences Scale (DES) to catch detachment and compartmentalization symptoms. Participants and methods The DES factor structure was evaluated in 768 psychiatric patients (546 women and 222 men) and in 2,403 subjects enrolled in nonpsychiatric settings (1,857 women and 546 men). All participants were administered the Italian version of DES. Twenty senior psychiatric experts in the treatment of dissociative symptoms independently assessed the DES items and categorized each of them as follows: “C” for compartmentalization, “D” for detachment, and “NC” for noncongruence with either C or D. Results Confirmatory factor analysis supported the three-factor structure of DES in both clinical and nonclinical samples and its invariance across the two groups. Moreover, factor analyses results overlapped with those from the expert classification procedure. Conclusion Our results showed that DES can be used as a valid instrument for clinicians to assess the frequency of different types of dissociative experiences including detachment and compartmentalization. PMID:27350746

  11. Foliar or root exposures to smelter particles: consequences for lead compartmentalization and speciation in plant leaves.

    Science.gov (United States)

    Schreck, Eva; Dappe, Vincent; Sarret, Géraldine; Sobanska, Sophie; Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna; Magnin, Valérie; Ranieri, Vincent; Dumat, Camille

    2014-04-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO4, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO3. In rye-grass, the changes in Pb speciation were even more egregious: Pb-cell wall and Pb-organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better assess the

  12. Hepatic Subcellular Compartmentation of Cytoplasmic Phosphoenolpyruvate Carboxykinase Determined by Immunogold Electron Microscopy

    Science.gov (United States)

    Gao, Kuixiong; Cardell, Emma Lou; Morris, Randal E.; Giffin, Bruce F.; Cardell, Robert R.

    1995-08-01

    Phosphoenolpyruvate carboxykinase (PEPCK) is the rate-limiting gluconeogenic enzyme and in liver occurs in a lobular gradient from periportal to pericentral regions. The subcellular distribution of cytoplasmic PEPCK molecules within hepatocytes and its relationship to organelles have not been determined previously. In this study, we have used immunogold electron microscopy to evaluate the subcellar distribution of the enzyme, in addition to brightfield and epipolarized light microscopy. Cryosections (10 [mu]m) of perfusion-fixed rat liver were collected on silanated slides and immunostained using goat anti-rat PEPCK followed by 5-nm gold-labeled secondary and tertiary antibodies. Additionally, free-floating vibratome sections (25, 50, and 100 [mu]m) of perfusion-immersion-fixed rat liver were immunogold stained using goat anti-rat PEPCK and 5-nm gold-labeled secondary antibody, with and without silver enhancement. The immunogold labeled sections from both procedures were embedded in epoxy resin for the preparation of thin sections for electron microscopy. The results showed that the gold-labeled antibodies penetrated the entire thickness of cryosections, resulting in a high signal for PEPCK, but membranes in general, the smooth endoplasmic reticulum in particular, were not identifiable as electron dense unit membranes. On the other hand, the vibratome sections of well-fixed tissue allowed good visualization of the ultrastructure of cellular organelles, with the smooth endoplasmic reticulum appearing as vesicles and tubules with electron dense unit membranes; however, the penetration of the gold-labeled antibody was limited to cells at the surface of the vibratome sections. In both procedures, PEPCK, as indicated by gold particles, is predominantly in the glycogen areas of the cytosome and not in mitochondria, nuclei, Golgi apparatus, or other cell organelles. Hepatocytes in periportal regions have a compact subcellular distribution of PEPCK shown by gold particles

  13. A compartmentalized mathematical model of the β1-adrenergic signaling system in mouse ventricular myocytes.

    Directory of Open Access Journals (Sweden)

    Vladimir E Bondarenko

    Full Text Available The β1-adrenergic signaling system plays an important role in the functioning of cardiac cells. Experimental data shows that the activation of this system produces inotropy, lusitropy, and chronotropy in the heart, such as increased magnitude and relaxation rates of [Ca(2+]i transients and contraction force, and increased heart rhythm. However, excessive stimulation of β1-adrenergic receptors leads to heart dysfunction and heart failure. In this paper, a comprehensive, experimentally based mathematical model of the β1-adrenergic signaling system for mouse ventricular myocytes is developed, which includes major subcellular functional compartments (caveolae, extracaveolae, and cytosol. The model describes biochemical reactions that occur during stimulation of β1-adrenoceptors, changes in ionic currents, and modifications of Ca(2+ handling system. Simulations describe the dynamics of major signaling molecules, such as cyclic AMP and protein kinase A, in different subcellular compartments; the effects of inhibition of phosphodiesterases on cAMP production; kinetics and magnitudes of phosphorylation of ion channels, transporters, and Ca(2+ handling proteins; modifications of action potential shape and duration; magnitudes and relaxation rates of [Ca(2+]i transients; changes in intracellular and transmembrane Ca(2+ fluxes; and [Na(+]i fluxes and dynamics. The model elucidates complex interactions of ionic currents upon activation of β1-adrenoceptors at different stimulation frequencies, which ultimately lead to a relatively modest increase in action potential duration and significant increase in [Ca(2+]i transients. In particular, the model includes two subpopulations of the L-type Ca(2+ channels, in caveolae and extracaveolae compartments, and their effects on the action potential and [Ca(2+]i transients are investigated. The presented model can be used by researchers for the interpretation of experimental data and for the developments of

  14. Heterogeneity of memory marginal zone B cells in the rat

    NARCIS (Netherlands)

    Hendricks, Jacobus

    2015-01-01

    The spleen is an important organ of the immune system. Like other lymphoid organs, the spleen is compartmentalized. Different compartments harbor different populations of lymphocytes, subpopulation of the white blood cells. One of these compartments in the spleen is the so-called marginal zone. Most

  15. The assembly of metals chelation by thiols and vacuolar compartmentalization conferred increased tolerance to and accumulation of cadmium and arsenic in transgenic Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiangbo [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China); Inner Mongolia Key Laboratory of Biomass-Energy Conversion, The Institute of Bioengineering and Technology, Inner Mongolia University of Science and Technology, Baotou 040100 (China); Xu, Wenzhong [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China); Ma, Mi, E-mail: mami@ibcas.ac.cn [Key Laboratory of Plant Resources, Institute of Botany, The Chinese Academy of Sciences, Beijing 100093 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Simultaneous transformation of AsPCS1 and ScYCF1 into Arabidopsis thaliana which is sensitive to heavy metals, leads to transgenic plants tolerant to Arsenic and cadmium. Black-Right-Pointing-Pointer Dual-gene transgenic Arabidopsis showed higher accumulation of Arsenic and cadmium than single and non-transgenic plants. Black-Right-Pointing-Pointer Our results proved that improved thiol peptides synthesis and vacuolar compartmentation in plant dramatically boosted the survival rates of plants when exposed to heavy metals. Black-Right-Pointing-Pointer A new strategy for efficient phytoremediation of heavy metals by stacking genes transformation in plants was developed in this article. - Abstract: Transgenic Arabidopsis thaliana were developed to increase tolerance for and accumulation of heavy metals and metalloids by simultaneous overexpression of AsPCS1 and YCF1 (derived from garlic and baker's yeast) based on the fact that chelation of metals and vacuolar compartmentalization are the main strategies for heavy metals/metalloids detoxification and tolerance in plants. Dual-gene transgenic lines had the longest roots and the highest accumulation of Cd and As than single-gene transgenic lines and wildtype. When grown on cadmium or arsenic (arsenite/arsenate), Dual-gene transgenic lines accumulated over 2-10 folds cadmium/arsenite and 2-3 folds arsenate than wild type or plants expressing AsPCS1 or YCF1 alone. Such stacking modified genes involved in chelation of toxic metals and vacuolar compartmentalization represents a highly promising new tool for use in phytoremediation efforts.

  16. Double-input compartmental modeling and spectral analysis for the quantification of positron emission tomography data in oncology

    Science.gov (United States)

    Tomasi, G.; Kimberley, S.; Rosso, L.; Aboagye, E.; Turkheimer, F.

    2012-04-01

    In positron emission tomography (PET) studies involving organs different from the brain, ignoring the metabolite contribution to the tissue time-activity curves (TAC), as in the standard single-input (SI) models, may compromise the accuracy of the estimated parameters. We employed here double-input (DI) compartmental modeling (CM), previously used for [11C]thymidine, and a novel DI spectral analysis (SA) approach on the tracers 5-[18F]fluorouracil (5-[18F]FU) and [18F]fluorothymidine ([18F]FLT). CM and SA were performed initially with a SI approach using the parent plasma TAC as an input function. These methods were then employed using a DI approach with the metabolite plasma TAC as an additional input function. Regions of interest (ROIs) corresponding to healthy liver, kidneys and liver metastases for 5-[18F]FU and to tumor, vertebra and liver for [18F]FLT were analyzed. For 5-[18F]FU, the improvement of the fit quality with the DI approaches was remarkable; in CM, the Akaike information criterion (AIC) always selected the DI over the SI model. Volume of distribution estimates obtained with DI CM and DI SA were in excellent agreement, for both parent 5-[18F]FU (R2 = 0.91) and metabolite [18F]FBAL (R2 = 0.99). For [18F]FLT, the DI methods provided notable improvements but less substantial than for 5-[18F]FU due to the lower rate of metabolism of [18F]FLT. On the basis of the AIC values, agreement between [18F]FLT Ki estimated with the SI and DI models was good (R2 = 0.75) for the ROIs where the metabolite contribution was negligible, indicating that the additional input did not bias the parent tracer only-related estimates. When the AIC suggested a substantial contribution of the metabolite [18F]FLT-glucuronide, on the other hand, the change in the parent tracer only-related parameters was significant (R2 = 0.33 for Ki). Our results indicated that improvements of DI over SI approaches can range from moderate to substantial and are more significant for tracers with

  17. Syntectonic fluid flow and fluid compartmentalization in a compressive basin: Example of the Jaca basin (Southwest Pyrenees, Spain)

    Science.gov (United States)

    Lacroix, Brice; Travé, Anna; Buatier, Martine; Labaume, Pierre

    2013-04-01

    During compressive events, deformation in sedimentary basins is mainly accommodated by thrust faults emplacement and related fold growth. In such a structure, thrust faults are generally rooted in the basement and may act as conduits or barriers for crustal fluid flow. However, most of recent studies suggest that fluid flow through such discontinuities is not so evident and depends on the structural levels of the thrust inside the fold-and-thrust belt. In order to constrain the paleofluid flow through the Jaca thrust-sheet-top basin (Paleogene southwest-Pyrenean fold-and-thrust belt) we focus our study on different thrust faults located at different structural levels. The microstructures observed in the different studied fault zones are similar and consist of pervasive cleavage, calcite shear and extension veins and late dilatation veins. In order to constrain the nature and the source of fluids involved in fluid-rock interactions in fault zones, a geochemical approach, based on oxygen and carbon stable isotopes and trace elements on calcite, was adopted on the different vein generations and host rocks. The results suggest a high complexity in the paleo-hydrological behaviors of thrust faults evidencing a fluid-flow compartmentalization of the basin. North of the Jaca basin, previous studies in the southern part of the Axial Zones showed the contribution of deep metamorphic water, probably derived from the Paleozoic basement, along along fault zones related the major Gavarnie thrust. Contrarily, in the northern part of the Jaca basin, we evidence the contribution of formation water during the Monte Perdido thrust fault activity. These data suggest a closed hydrological fluid system where distance of fluid flow did not exceeded 70 m. On the other hand, the Jaca and Cotiella thrust faults, both located more to the south in the basin, are characterized by a composite fluid flow system. Indeed, stable isotopes and trace elements compositions of the first generation of

  18. Inhibition of glutathione biosynthesis alters compartmental redox status and the thiol proteome in organogenesis-stage rat conceptuses.

    Science.gov (United States)

    Harris, Craig; Shuster, Daniel Z; Roman Gomez, Rosaicela; Sant, Karilyn E; Reed, Matthew S; Pohl, Jan; Hansen, Jason M

    2013-10-01

    oxidation was seen in the BSO-treated AF compartment after 6 h. Biotinylated iodoacetamide (BIAM) labeling of proteins revealed the significant thiol oxidation of many EMB proteins following BSO treatment. Quantitative changes in the thiol proteome, associated with developmentally relevant pathways, were detected using isotope coded affinity tag (ICAT) labeling and mass spectroscopy. Adaptive pathways were selectively enriched with increased concentrations of proteins involved in mRNA processing (splicesome) and mRNA stabilization (glycolysis, GAPDH), as well as protein synthesis (aminoacyl-tRNA) and protein folding (antigen processing, Hsp70, protein disulfide isomerase). These results show the ability of chemical and environmental modulators to selectively alter compartmental intracellular and extracellular GSH and Cys concentrations and change their corresponding E(h) within the intact viable conceptus. The altered E(h) were also of sufficient magnitude to alter the redox proteome and change relative protein concentrations, suggesting that the mechanistic links through which environmental factors inform and regulate developmental signaling pathways may be discovered using systems developmental biology techniques. PMID:23736079

  19. Utilization of stable isotopes for the study of in vivo compartmental metabolism of poly-insaturate fatty acids; Utilisation des isotopes stables pour l`etude du metabolisme compartimental in vivo d`acides gras polyinsatures

    Energy Technology Data Exchange (ETDEWEB)

    Brossard, N.; Croset, M.; Lecerf, J.; Lagarde, M. [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France); Pachiaudi, C.; Normand, S.; Riou, J.P. [Faculte de Medecine, 69 - Lyon (France); Chirouze, V.; Tayot, J.L. [IMEDEX, 69 - Chaponost (France)

    1994-12-31

    In order to study the compartmental metabolism of the 22:6n-3 fatty acid, and particularly the role of the transport plasmatic forms for the tissue uptake (especially brain), a technique is developed using carbon 13 stable isotope and an isotopic mass spectrometry coupled to gaseous chromatography technique. This method has been validated in rat with docosahexaenoic acid enriched in {sup 13}C and esterified in triglycerides. The compartmental metabolism is monitored by measuring the variation of 22:6n-3 isotopic enrichment in the various lipoprotein lipidic fractions, in blood globules and in the brain. 1 fig., 1 tab., 12 refs.

  20. A new view into prokaryotic cell biology from electron cryotomography

    OpenAIRE

    Oikonomou, Catherine M.; Jensen, Grant J.

    2016-01-01

    Electron cryotomography (ECT) enables intact cells to be visualized in 3D in an essentially native state to 'macromolecular' (~4 nm) resolution, revealing the basic architectures of complete nanomachines and their arrangements in situ. Since its inception, ECT has advanced our understanding of many aspects of prokaryotic cell biology, from morphogenesis to subcellular compartmentalization and from metabolism to complex interspecies interactions. In this Review, we highlight how ECT has provid...

  1. Cooperative catalysis of noncompatible catalysts through compartmentalization: wacker oxidation and enzymatic reduction in a one-pot process in aqueous media.

    Science.gov (United States)

    Sato, Hirofumi; Hummel, Werner; Gröger, Harald

    2015-04-01

    A Wacker oxidation using CuCl/PdCl2 as a catalyst system was successfully combined with an enzymatic ketone reduction to convert styrene enantioselectively into 1-phenylethanol in a one-pot process, although the two reactions conducted in aqueous media are not compatible due to enzyme deactivation by Cu ions. The one-pot feasibility was achieved via compartmentalization of the reactions. Conducting the Wacker oxidation in the interior of a polydimethylsiloxane thimble enables diffusion of only the organic substrate and product into the exterior where the biotransformation takes place. Thus, the Cu ions detrimental to the enzyme are withheld from the reaction media of the biotransformation. In this one-pot process, which formally corresponds to an asymmetric hydration of alkenes, a range of 1-arylethanols were formed with high conversions and 98-99 % ee. In addition, the catalyst system of the Wacker oxidation was recycled 15 times without significant decrease in conversion. PMID:25704961

  2. A multi-stage compartmental model for HIV-infected individuals: II--application to insurance functions and health-care costs.

    Science.gov (United States)

    Billard, L; Dayananda, P W A

    2014-03-01

    Stochastic population processes have received a lot of attention over the years. One approach focuses on compartmental modeling. Billard and Dayananda (2012) developed one such multi-stage model for epidemic processes in which the possibility that individuals can die at any stage from non-disease related causes was also included. This extra feature is of particular interest to the insurance and health-care industries among others especially when the epidemic is HIV/AIDS. Rather than working with numbers of individuals in each stage, they obtained distributional results dealing with the waiting time any one individual spent in each stage given the initial stage. In this work, the impact of the HIV/AIDS epidemic on several functions relevant to these industries (such as adjustments to premiums) is investigated. Theoretical results are derived, followed by a numerical study.

  3. Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Marianna S.; Newman, David; Kasmai, Bahman; Greenwood, Richard; Malcolm, Paul N. [Norfolk and Norwich University Hospital, Department of Radiology, Norwich (United Kingdom); Leinhard, Olof Dahlqvist [Linkoeping University, Center for Medical Image Science and Visualization, Linkoeping (Sweden); Linkoeping University, Department of Medical and Health Sciences, Linkoeping (Sweden); Karlsson, Anette; Borga, Magnus [Linkoeping University, Center for Medical Image Science and Visualization, Linkoeping (Sweden); Linkoeping University, Department of Biomedical Engineering, Linkoeping (Sweden); Rosander, Johannes [Advanced MR Analytics AB, Linkoeping (Sweden); Toms, Andoni P. [Norfolk and Norwich University Hospital, Department of Radiology, Norwich (United Kingdom); Radiology Academy, Cotman Centre, Norwich, Norfolk (United Kingdom)

    2014-09-15

    To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI. Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes. Mean automated total body muscle volume was 19.32 L (SD9.1) and 19.28 L (SD9.12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1.0, 95 % level of agreement -0.32-0.2 L). ICC for all automated test-retest muscle volumes were almost perfect (0.99-1.0) with 95 % levels of agreement 1.8-6.6 % of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1.68 L (2SD0.6) compared to automated 1.64 L (2SD 0.6), left lower leg: manual 1.69 L (2SD 0.64) compared to automated 1.63 L (SD0.61), correlation coefficients for automated and manual segmentation were 0.94-0.96). Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg. (orig.)

  4. Test-retest reliability of automated whole body and compartmental muscle volume measurements on a wide bore 3T MR system

    International Nuclear Information System (INIS)

    To measure the test-retest reproducibility of an automated system for quantifying whole body and compartmental muscle volumes using wide bore 3 T MRI. Thirty volunteers stratified by body mass index underwent whole body 3 T MRI, two-point Dixon sequences, on two separate occasions. Water-fat separation was performed, with automated segmentation of whole body, torso, upper and lower leg volumes, and manually segmented lower leg muscle volumes. Mean automated total body muscle volume was 19.32 L (SD9.1) and 19.28 L (SD9.12) for first and second acquisitions (Intraclass correlation coefficient (ICC) = 1.0, 95 % level of agreement -0.32-0.2 L). ICC for all automated test-retest muscle volumes were almost perfect (0.99-1.0) with 95 % levels of agreement 1.8-6.6 % of mean volume. Automated muscle volume measurements correlate closely with manual quantification (right lower leg: manual 1.68 L (2SD0.6) compared to automated 1.64 L (2SD 0.6), left lower leg: manual 1.69 L (2SD 0.64) compared to automated 1.63 L (SD0.61), correlation coefficients for automated and manual segmentation were 0.94-0.96). Fully automated whole body and compartmental muscle volume quantification can be achieved rapidly on a 3 T wide bore system with very low margins of error, excellent test-retest reliability and excellent correlation to manual segmentation in the lower leg. (orig.)

  5. Effect of scatter correction on the compartmental measurement of striatal and extrastriatal dopamine D2 receptors using [123I]epidepride SPET.

    Science.gov (United States)

    Fujita, Masahiro; Varrone, Andrea; Kim, Kyeong Min; Watabe, Hiroshi; Zoghbi, Sami S; Seneca, Nicholas; Tipre, Dnyanesh; Seibyl, John P; Innis, Robert B; Iida, Hidehiro

    2004-05-01

    Prior studies with anthropomorphic phantoms and single, static in vivo brain images have demonstrated that scatter correction significantly improves the accuracy of regional quantitation of single-photon emission tomography (SPET) brain images. Since the regional distribution of activity changes following a bolus injection of a typical neuroreceptor ligand, we examined the effect of scatter correction on the compartmental modeling of serial dynamic images of striatal and extrastriatal dopamine D(2) receptors using [(123)I]epidepride. Eight healthy human subjects [age 30+/-8 (range 22-46) years] participated in a study with a bolus injection of 373+/-12 (354-389) MBq [(123)I]epidepride and data acquisition over a period of 14 h. A transmission scan was obtained in each study for attenuation and scatter correction. Distribution volumes were calculated by means of compartmental nonlinear least-squares analysis using metabolite-corrected arterial input function and brain data processed with scatter correction using narrow-beam geometry micro (SC) and without scatter correction using broad-beam micro (NoSC). Effects of SC were markedly different among brain regions. SC increased activities in the putamen and thalamus after 1-1.5 h while it decreased activity during the entire experiment in the temporal cortex and cerebellum. Compared with NoSC, SC significantly increased specific distribution volume in the putamen (58%, P=0.0001) and thalamus (23%, P=0.0297). Compared with NoSC, SC made regional distribution of the specific distribution volume closer to that of [(18)F]fallypride. It is concluded that SC is required for accurate quantification of distribution volumes of receptor ligands in SPET studies. PMID:14730406

  6. Effect of scatter correction on the compartmental measurement of striatal and extrastriatal dopamine D2 receptors using [123I]epidepride SPET

    International Nuclear Information System (INIS)

    Prior studies with anthropomorphic phantoms and single, static in vivo brain images have demonstrated that scatter correction significantly improves the accuracy of regional quantitation of single-photon emission tomography (SPET) brain images. Since the regional distribution of activity changes following a bolus injection of a typical neuroreceptor ligand, we examined the effect of scatter correction on the compartmental modeling of serial dynamic images of striatal and extrastriatal dopamine D2 receptors using [123I]epidepride. Eight healthy human subjects [age 30±8 (range 22-46) years] participated in a study with a bolus injection of 373±12 (354-389) MBq [123I]epidepride and data acquisition over a period of 14 h. A transmission scan was obtained in each study for attenuation and scatter correction. Distribution volumes were calculated by means of compartmental nonlinear least-squares analysis using metabolite-corrected arterial input function and brain data processed with scatter correction using narrow-beam geometry μ (SC) and without scatter correction using broad-beam μ (NoSC). Effects of SC were markedly different among brain regions. SC increased activities in the putamen and thalamus after 1-1.5 h while it decreased activity during the entire experiment in the temporal cortex and cerebellum. Compared with NoSC, SC significantly increased specific distribution volume in the putamen (58%, P=0.0001) and thalamus (23%, P=0.0297). Compared with NoSC, SC made regional distribution of the specific distribution volume closer to that of [18F]fallypride. It is concluded that SC is required for accurate quantification of distribution volumes of receptor ligands in SPET studies. (orig.)

  7. Effect of scatter correction on the compartmental measurement of striatal and extrastriatal dopamine D{sub 2} receptors using [{sup 123}I]epidepride SPET

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Masahiro; Seneca, Nicholas; Innis, Robert B. [Department of Psychiatry, Yale University School of Medicine and VA Connecticut Healthcare System, West Haven, CT (United States); Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD (United States); Varrone, Andrea [Department of Psychiatry, Yale University School of Medicine and VA Connecticut Healthcare System, West Haven, CT (United States); Biostructure and Bioimaging Institute, National Research Council, Napoli (Italy); Kim, Kyeong Min; Watabe, Hiroshi; Iida, Hidehiro [Department of Investigative Radiology, National Cardiovascular Center Research Institute, Osaka (Japan); Zoghbi, Sami S. [Department of Psychiatry, Yale University School of Medicine and VA Connecticut Healthcare System, West Haven, CT (United States); Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD (United States); Department of Radiology, Yale University School of Medicine and VA Connecticut Healthcare System, West Haven, CT (United States); Tipre, Dnyanesh [Molecular Imaging Branch, National Institute of Mental Health, Bethesda, MD (United States); Seibyl, John P. [Institute for Neurodegenerative Disorders, New Haven, CT (United States)

    2004-05-01

    Prior studies with anthropomorphic phantoms and single, static in vivo brain images have demonstrated that scatter correction significantly improves the accuracy of regional quantitation of single-photon emission tomography (SPET) brain images. Since the regional distribution of activity changes following a bolus injection of a typical neuroreceptor ligand, we examined the effect of scatter correction on the compartmental modeling of serial dynamic images of striatal and extrastriatal dopamine D{sub 2} receptors using [{sup 123}I]epidepride. Eight healthy human subjects [age 30{+-}8 (range 22-46) years] participated in a study with a bolus injection of 373{+-}12 (354-389) MBq [{sup 123}I]epidepride and data acquisition over a period of 14 h. A transmission scan was obtained in each study for attenuation and scatter correction. Distribution volumes were calculated by means of compartmental nonlinear least-squares analysis using metabolite-corrected arterial input function and brain data processed with scatter correction using narrow-beam geometry {mu} (SC) and without scatter correction using broad-beam {mu} (NoSC). Effects of SC were markedly different among brain regions. SC increased activities in the putamen and thalamus after 1-1.5 h while it decreased activity during the entire experiment in the temporal cortex and cerebellum. Compared with NoSC, SC significantly increased specific distribution volume in the putamen (58%, P=0.0001) and thalamus (23%, P=0.0297). Compared with NoSC, SC made regional distribution of the specific distribution volume closer to that of [{sup 18}F]fallypride. It is concluded that SC is required for accurate quantification of distribution volumes of receptor ligands in SPET studies. (orig.)

  8. PET-based compartmental modeling of {sup 124}I-A33 antibody: quantitative characterization of patient-specific tumor targeting in colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zanzonico, Pat; O' Donoghue, Joseph A.; Humm, John L. [Memorial Sloan Kettering Cancer Center, Department of Medical Physics, New York, NY (United States); Carrasquillo, Jorge A.; Pandit-Taskar, Neeta; Ruan, Shutian; Larson, Steven M. [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Smith-Jones, Peter [Memorial Sloan Kettering Cancer Center, Department of Radiology, New York, NY (United States); Stony Brook School of Medicine, Departments of Psychiatry and Radiology, Stony Brook, NY (United States); Divgi, Chaitanya [Columbia University Medical Center, New York, NY (United States); Scott, Andrew M. [La Trobe University, Olivia Newton-John Cancer Research Institute, Melbourne (Australia); Kemeny, Nancy E.; Wong, Douglas; Scheinberg, David [Memorial Sloan Kettering Cancer Center, Department of Medicine, New York, NY (United States); Fong, Yuman [Memorial Sloan Kettering Cancer Center, Department of Surgery, New York, NY (United States); City of Hope, Department of Surgery, Duarte, CA (United States); Ritter, Gerd; Jungbluth, Achem; Old, Lloyd J. [Memorial Sloan Kettering Cancer Center, Ludwig Institute for Cancer Research, New York, NY (United States)

    2015-10-15

    The molecular specificity of monoclonal antibodies (mAbs) directed against tumor antigens has proven effective for targeted therapy of human cancers, as shown by a growing list of successful antibody-based drug products. We describe a novel, nonlinear compartmental model using PET-derived data to determine the ''best-fit'' parameters and model-derived quantities for optimizing biodistribution of intravenously injected {sup 124}I-labeled antitumor antibodies. As an example of this paradigm, quantitative image and kinetic analyses of anti-A33 humanized mAb (also known as ''A33'') were performed in 11 colorectal cancer patients. Serial whole-body PET scans of {sup 124}I-labeled A33 and blood samples were acquired and the resulting tissue time-activity data for each patient were fit to a nonlinear compartmental model using the SAAM II computer code. Excellent agreement was observed between fitted and measured parameters of tumor uptake, ''off-target'' uptake in bowel mucosa, blood clearance, tumor antigen levels, and percent antigen occupancy. This approach should be generally applicable to antibody-antigen systems in human tumors for which the masses of antigen-expressing tumor and of normal tissues can be estimated and for which antibody kinetics can be measured with PET. Ultimately, based on each patient's resulting ''best-fit'' nonlinear model, a patient-specific optimum mAb dose (in micromoles, for example) may be derived. (orig.)

  9. Glutamine analogs promote cytoophidium assembly in human and Drosophila cells

    Institute of Scientific and Technical Information of China (English)

    Kangni Chen; Jing Zhang; (O)mür Yilmaz Tastan; Zillah Anne Deussen; Mayte Yu-Yin Siswick; Ji-Long Liu

    2011-01-01

    CTP synthase is compartmentalized within a subcellular structure,termed the cytoophidium,in a range of organisms including bacteria,yeast,fruit fly and rat.Here we show that CTP synthase is also compartmentalized into cytoophidia in human cells.Surprisingly,the occurrence of cyloophidia in human cells increases upon treatment with a glutamine analog 6-diazo-5-oxo-L-norleucine (DON),an inhibitor of glutaminedependent enzymes including CTP synthase.Experiments in flies confirmned that DON globally promotes cytoophidium assembly.Clonal analysis via CTP synthase RNA interference in somatic cells indicates that CTP synthase expression level is critical for the formation of cytoophidia.Moreover,DON facilitates cytoophidium assembly even when CTP synthase level is low.A second glutamine analog azaserine also promotes cytoophidum formation.Our data demonstrate that glutamine analogs serve as useful tools in the study of cytoophidia.

  10. Scaffolding during the cell cycle by A-kinase anchoring proteins

    OpenAIRE

    Han, B.; Poppinga, W J; Schmidt, M.

    2015-01-01

    Cell division relies on coordinated regulation of the cell cycle. A process including a well-defined series of strictly regulated molecular mechanisms involving cyclin-dependent kinases, retinoblastoma protein, and polo-like kinases. Dysfunctions in cell cycle regulation are associated with disease such as cancer, diabetes, and neurodegeneration. Compartmentalization of cellular signaling is a common strategy used to ensure the accuracy and efficiency of cellular responses. Compartmentalizati...

  11. Method and apparatus for sustaining viability of biological cells on a substrate

    Science.gov (United States)

    McKnight, Timothy E.; Melechko, Anatoli V.; Simpson, Michael L.

    2011-12-13

    A method for the transient transformation of a living biological cell having an intact cell membrane defining an intracellular domain, and an apparatus for the transient transformation of biological cells. The method and apparatus include introducing a compartmentalized extracellular component fixedly attached to a cellular penetrant structure to the intracellular domain of the cell, wherein the cell is fixed in a predetermined location and wherein the component is expressed within in the cell while being retained within the compartment and wherein the compartment restricts the mobility and interactions of the component within the cell and prevents transference of the component to the cell.

  12. Lyophilized kits of diamino dithiol compounds for labelling with 99m-technetium. Pharmacokinetics studies and distribution compartmental models of the related complexes

    International Nuclear Information System (INIS)

    The present work reflects the clinical interest for labelling diamino dithiol compounds with technetium-99m. Both chosen compounds, L,L-Ethylene dicysteine (L,L-EC) and L,L-Ethylene dicysteine diethyl esther (L,L-ECD) were obtained with relative good yield and characterized by IR and NMR. The study of labelling conditions with technetium-99m showed the influence of the type and mass of reducing agent as well as the pH on the formation of complexes with desired biological characteristics. Radiochemical purity was determined by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Lyophilised kits of L,L-EC and L,L-ECD for labelling with 99mTc were obtained, with stability superior to 120 days, when stored under refrigeration, enabling the kits marketing. The ideal formulation of the kits as well as the use of liquid nitrogen in the freezing process, determined the lyophilization success. Distribution biological studies of the 99mTc complexes were performed on mice by invasive method and on bigger animals by scintigraphic evaluation. Biological distribution studies of the complex 99mTc-L,L-EC showed fast blood clearance, with the elimination of about 90% of the administered dose after 60 minutes, almost exclusively by the urinary system. The biological distribution results were adjusted to a three compartmental distribution model, as expected for a radiopharmaceutical designed to renal dynamic studies, with tubular elimination. The complex interaction with renal tubular receptors is related with structural characteristics of the compound, more specifically with the presence and location of polar groups. In comparison with 99mTc-L,L-EC, biological studies of the complex 99mTc -L,L-ECD showed different distribution aspects, despite some structural similarities. The presence of ethyl groups confers to the complex neutrality and lipophilicity. It cross the intact blood brain barrier and is retained in the brain for enough period, permitting

  13. Estimate of FDG Excretion by means of Compartmental Analysis and Ant Colony Optimization of Nuclear Medicine Data

    OpenAIRE

    Sara Garbarino; Giacomo Caviglia; Massimo Brignone; Michela Massollo; Gianmario Sambuceti; Michele Piana

    2013-01-01

    [18F]fluoro-2-deoxy-D-glucose (FDG) is one of the most utilized tracers for positron emission tomography (PET) applications in oncology. FDG-PET relies on higher glycolytic activity in tumors compared to normal structures as the basis of image contrast. As a glucose analog, FDG is transported into malignant cells which typically exhibit an increased radioactivity. However, different from glucose, FDG is not reabsorbed by the renal system and is excreted to the bladder. The present paper de...

  14. Identification of cytoskeletal elements enclosing the ATP pools that fuel human red blood cell membrane cation pumps

    OpenAIRE

    Chu, Haiyan; Puchulu-Campanella, Estela; Galan, Jacob A.; Tao, W. Andy; Low, Philip S.; Hoffman, Joseph F.

    2012-01-01

    The type of metabolic compartmentalization that occurs in red blood cells differs from the types that exist in most eukaryotic cells, such as intracellular organelles. In red blood cells (ghosts), ATP is sequestered within the cytoskeletal–membrane complex. These pools of ATP are known to directly fuel both the Na+/K+ and Ca2+ pumps. ATP can be entrapped within these pools either by incubation with bulk ATP or by operation of the phosphoglycerate kinase and pyruvate kinase reactions to enzyma...

  15. Compartmental analysis and dosimetric aspects applied to cholesterol with {sup 3}H labeled; Analise compartimental e aspectos dosimetricos aplicados ao colesterol marcado com {sup 3}H

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Adriano dos Santos

    2015-07-01

    Cardiovascular diseases (CVDs) are one of the major reasons of death around the world according to the World Health Organization (WHO). It is well known that changes in levels of plasma lipoproteins, which are responsible for the transport of cholesterol into the bloodstream, are associated with cardiovascular diseases. For this reason to know the biokinetic parameters of plasma lipoproteins and quantifies them is important to correct and deep understanding about the diseases associated with these disorders. The main aim of this study is to provide a biokinetic model and estimate the radiometric doses for {sup 3}H-Cholesterol, a radioactive tracer widely used in physiological and metabolic studies. The model was based on [Schwartz et al. 2004] about the distribution of cholesterol by the lipoprotein and gastrointestinal model [ICRP 30, 1979]. The doses distribution in compartments of the model and other organs and tissues of a standard adult described in [ICRP 106, 2008] was calculated using MIRD method (Medical Internal Radiation Dose) and compartmental analysis using the computer program Matlab®. The dose coefficients were estimated for a standard phantom man (73 kg) described in [ICRP 60, 1991]. The estimated doses for both model and for other organs were low and did not exceed the highest dose obtained that was in the upper large intestine, as 44,8 μGy these parameters will assist in ethics committee's opinions on the use of works that use the {sup 3}H-cholesterol which radioactive tracer. (author)

  16. Building America Case Study: Apartment Compartmentalization with an Aerosol-Based Sealing Process - Queens, NY; Technology Solutions for New and Existing Homes, Energy Efficiency & Renewable Energy (EERE)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-07-01

    Air sealing of building enclosures is a difficult and time-consuming process. Current methods in new construction require laborers to physically locate small and sometimes large holes in multiple assemblies and then manually seal each of them. The innovation demonstrated under this research study was the automated air sealing and compartmentalization of buildings through the use of an aerosolized sealant, developed by the Western Cooling Efficiency Center at University of California Davis.
    CARB sought to demonstrate this new technology application in a multifamily building in Queens, NY. The effectiveness of the sealing process was evaluated by three methods: air leakage testing of overall apartment before and after sealing, point-source testing of individual leaks, and pressure measurements in the walls of the target apartment during sealing. Aerosolized sealing was successful by several measures in this study. Many individual leaks that are labor-intensive to address separately were well sealed by the aerosol particles. In addition, many diffuse leaks that are difficult to identify and treat were also sealed. The aerosol-based sealing process resulted in an average reduction of 71% in air leakage across three apartments and an average apartment airtightness of 0.08 CFM50/SF of enclosure area.

  17. Compartmentalized and contrasted response of ectomycorrhizal and soil fungal communities of Scots pine forests along elevation gradients in France and Spain.

    Science.gov (United States)

    Rincón, Ana; Santamaría-Pérez, Blanca; Rabasa, Sonia G; Coince, Aurore; Marçais, Benoit; Buée, Marc

    2015-08-01

    Fungi are principal actors of forest soils implied in many ecosystem services and the mediation of tree's responses. Forecasting fungal responses to environmental changes is necessary for maintaining forest productivity, although our partial understanding of how abiotic and biotic factors affect fungal communities is restricting the predictions. We examined fungal communities of Pinus sylvestris along elevation gradients to check potential responses to climate change-associated factors. Fungi of roots and soils were analysed at a regional scale, by using a high-throughput sequencing approach. Overall soil fungal richness increased with pH, whereas it did not vary with climate. However, when representative sub-assemblages, i.e. Ascomycetes/Basidiomycetes, and families were analysed, they differentially answered to climatic and edaphic variables. This response was dependent on where they settled, i.e. soil versus roots, and/or on their lifestyle, i.e. mycorrhizal or not, suggesting different potential functional weights within the community. Our results revealed a highly compartmentalized and contrasted response of fungal communities in forest soils. The different response of fungal sub-assemblages indicated a range of possible selective direct and indirect (i.e. via host) impacts of climatic variations on these communities, of unknown functional consequences, that helps in understanding potential fungal responses under future global change scenarios. PMID:25953485

  18. Compartmentalized Self-Replication under fast PCR cycling conditions yields Taq DNA polymerase mutants with increased DNA-binding affinity and blood resistance

    Directory of Open Access Journals (Sweden)

    Bahram eArezi

    2014-08-01

    Full Text Available Faster-cycling PCR formulations, protocols, and instruments have been developed to address the need for increased throughput and shorter turn-around times for PCR-based assays. Although run times can be cut by up to 50%, shorter cycle times have been correlated with lower detection sensitivity and increased variability. To address these concerns, we applied Compartmentalized Self Replication (CSR to evolve faster-cycling mutants of Taq DNA polymerase. After five rounds of selection using progressively shorter PCR extension times, individual mutations identified in the fastest-cycling clones were randomly combined using ligation-based multi-site mutagenesis. The best-performing combinatorial mutants exhibit 35- to 90-fold higher affinity (lower Kd for primed template and a moderate (2-fold increase in extension rate compared to wild-type Taq. Further characterization revealed that CSR-selected mutations provide increased resistance to inhibitors, and most notably, enable direct amplification from up to 65% whole blood. We discuss the contribution of individual mutations to fast-cycling and blood-resistant phenotypes.

  19. Development of a paediatric population pharmacokinetic model for valacyclovir from literature non-compartmental values originating from sparse studies and Bayesian priors: a simulation study.

    Science.gov (United States)

    Kechagia, Irene-Ariadne; Dokoumetzidis, Aristides

    2015-06-01

    A preliminary population pharmacokinetic (PopPK) model of valacyclovir in children was developed from non-compartmental analysis (NCA) parameter values from literature, including several age groups, combined with Bayesian priors from a PopPK model of acyclovir, the active metabolite of valacyclovir, from literature too. Also a simulation study was carried out to evaluate the performance of various modelling choices related to the estimation of model parameters from NCA parameters originating from sparse PK studies. Assuming a one-compartment model with first order absorption, a mixed effects, meta-analysis approach was utilized which allows accounting the random intergroup variability, the detection of covariates and the application of informative Bayesian priors on the parameters. The conclusions from the simulation study calculating bias and precision for various cases, were that a model which takes explicitly into account the sampling schedule, performs better than a model using the theoretical expressions of calculating the NCA parameters. Also by using the geometric rather than the arithmetic means of NCA parameters, less biased results are obtained. These findings guided the choices for the valacyclovir model, for which informative priors from a PopPK model of acyclovir were applied for some of the parameters, in order to include a richer covariate model for clearance, not supported by the NCA dataset and a value for bioavailability. This preliminary valacyclovir model can be used in simulations to provide dosage recommendations for children of various ages and to help design more efficiently prospective clinical trials. PMID:25821006

  20. Transcriptomic analysis of Streptomyces coelicolor differentiation in solid sporulating cultures: first compartmentalized and second multinucleated mycelia have different and distinctive transcriptomes.

    Directory of Open Access Journals (Sweden)

    Paula Yagüe

    Full Text Available Streptomycetes are very important industrial bacteria, which produce two thirds of all clinically relevant secondary metabolites. They have a complex developmental-cycle in which an early compartmentalized mycelium (MI differentiates to a multinucleated mycelium (MII that grows inside the culture medium (substrate mycelium until it starts to growth into the air (aerial mycelium and ends up forming spores. Streptomyces developmental studies have focused mainly on the later stages of MII differentiation (aerial mycelium and sporulation, with regulation of pre-sporulation stages (MI/MII transition essentially unknown. This work represents the first study of the Streptomyces MI transcriptome, analyzing how it differs from the MII transcriptome. We have used a very conservative experimental approach to fractionate MI from MII and quantify gene expressions. The expression of well characterized key developmental/metabolic genes involved in bioactive compound production (actinorhodin, undecylprodigiosin, calcium-dependent antibiotic, cpk, geosmin or hydrophobic cover formation-sporulation (bld, whi, wbl, rdl, chp, ram was correlated with MII differentiation. Additionally, 122 genes conserved in the Streptomyces genus, whose biological function had not been previously characterized, were found to be differentially expressed (more than 4-fold in MI or MII. These genes encoded for putative regulatory proteins (transcriptional regulators, kinases, as well as hypothetical proteins. Knowledge about differences between the MI (vegetative and MII (reproductive transcriptomes represents a huge advance in Streptomyces biology that will make future experiments possible aimed at characterizing the biochemical pathways controlling pre-sporulation developmental stages and activation of secondary metabolism in Streptomyces.

  1. Compartmentation of Metabolism of the C12-, C9-, and C5-n-dicarboxylates in Rat Liver, Investigated by Mass Isotopomer Analysis: ANAPLEROSIS FROM DODECANEDIOATE.

    Science.gov (United States)

    Jin, Zhicheng; Bian, Fang; Tomcik, Kristyen; Kelleher, Joanne K; Zhang, Guo-Fang; Brunengraber, Henri

    2015-07-24

    We investigated the compartmentation of the catabolism of dodecanedioate (DODA), azelate, and glutarate in perfused rat livers, using a combination of metabolomics and mass isotopomer analyses. Livers were perfused with recirculating or nonrecirculating buffer containing one fully (13)C-labeled dicarboxylate. Information on the peroxisomal versus mitochondrial catabolism was gathered from the labeling patterns of acetyl-CoA proxies, i.e. total acetyl-CoA, the acetyl moiety of citrate, C-1 + 2 of β-hydroxybutyrate, malonyl-CoA, and acetylcarnitine. Additional information was obtained from the labeling patterns of citric acid cycle intermediates and related compounds. The data characterize the partial oxidation of DODA and azelate in peroxisomes, with terminal oxidation in mitochondria. We did not find evidence of peroxisomal oxidation of glutarate. Unexpectedly, DODA contributes a substantial fraction to anaplerosis of the citric acid cycle. This opens the possibility to use water-soluble DODA in nutritional or pharmacological anaplerotic therapy when other anaplerotic substrates are impractical or contraindicated, e.g. in propionic acidemia and methylmalonic acidemia.

  2. Contribution of Chitinase A’s C-Terminal Vacuolar Sorting Determinant to the Study of Soluble Protein Compartmentation

    Directory of Open Access Journals (Sweden)

    Egidio Stigliano

    2014-06-01

    Full Text Available Plant chitinases have been studied for their importance in the defense of crop plants from pathogen attacks and for their peculiar vacuolar sorting determinants. A peculiarity of the sequence of many family 19 chitinases is the presence of a C-terminal extension that seems to be important for their correct recognition by the vacuole sorting machinery. The 7 amino acids long C-terminal vacuolar sorting determinant (CtVSD of tobacco chitinase A is necessary and sufficient for the transport to the vacuole. This VSD shares no homology with other CtVSDs such as the phaseolin’s tetrapeptide AFVY (AlaPheValTyr and it is also sorted by different mechanisms. While a receptor for this signal has not yet been convincingly identified, the research using the chitinase CtVSD has been very informative, leading to the observation of phenomena otherwise difficult to observe such as the presence of separate vacuoles in differentiating cells and the existence of a Golgi-independent route to the vacuole. Thanks to these new insights in the endoplasmic reticulum (ER-to-vacuole transport, GFPChi (Green Fluorescent Protein carrying the chitinase A CtVSD and other markers based on chitinase signals will continue to help the investigation of vacuolar biogenesis in plants.

  3. Krüppel-like factor 9 regulates cell proliferation and compartmental expression of estrogen and progesterone receptors in the mouse uterine endometrium

    Science.gov (United States)

    The uterine endometrium undergoes dynamic changes in proliferation and differentiation in response to estrogen (E) and progesterone (P) during the estrous cycle and pregnancy. E and P exert their functions through their respective nuclear receptors, estrogen receptor (ESR) and progesterone receptor ...

  4. Refinement of the kinetic model of the 2-[14C]deoxyglucose method to incorporate effects of intracellular compartmentation in brain

    International Nuclear Information System (INIS)

    A translocase to transport hexose phosphate formed in the cytosol into the cisterns of the endoplasmic reticulum, where the phosphatase resides, is absent in brain. 2-Deoxyglucose-6-phosphate (DG-6-P) may therefore have limited access to glucose-6-phosphatase (G-6-Pase), and transport of the DG-6-P across the endoplasmic reticular membrane may be rate limiting to its dephosphorylation. To take this compartmentation into account, a five-rate constant (5K) model was developed to describe the kinetic behavior of 2-deoxyglucose (DG) and its phosphorylated product in brain. Loss of DG-6-P was modeled as a two-step process: (a) transfer of DG-6-P from the cytosol into the cisterns of the endoplasmic reticulum; (b) hydrolysis of DG-6-P by G-6-Pase and subsequent return of the free DG to the precursor pool. Local CMRglc (LCMRglc) was calculated in the rat on the basis of this model and compared with values calculated on the basis of the three-rate constant (3K) and the four-rate constant (4K) models of the DG method. The results show that under normal physiological conditions all three models yield values of LCMRglc that are essentially equivalent for experimental periods between 25 and 45 min. Therefore, the simplest model, the 3K model, is sufficient. For experimental periods from 60 to 120 min, the 4K and 5K models do not correct completely for loss of product, but the 5K model does yield estimates of LCMRglc that are closer to the values at 45 min than those obtained with the 3K and 4K models

  5. Survey on modeling methods for single compartmental spiking neuron%单房室脉冲神经元建模方法综述

    Institute of Scientific and Technical Information of China (English)

    蔺想红; 巩祖正

    2011-01-01

    要通过人工神经网络来模拟神经系统的功能并对实际问题进行求解,构建合适的脉冲神经元模型非常重要.为了使研究者了解此问题的研究进展,对目前的单房室脉冲神经元建模方法进行了综述.根据复杂程度将这些模型分为三类:具有生物可解释性的生理模型,具有脉冲生成机制的非线性模型和具有固定阈值的线性模型,对各类不同建模方法进行了阐述和分析,并讨论了各自的优缺点.%To simulate the function of the nervous system and solve practical problems using artificial neural networks,modeling suitable spiking neuron models is very importantAn overview is provided for the researchers to catch up with the lately research progress of the modeling methods of single compartmental spiking neuron.According to the complexity,these models will be divided into three categories:physiological models with biologically plausibility,nonlinear models with spiking mecha nism and linear models with fixed threshold.Different methods are described and analyzed respectively, and their advantages and disadvantages are discussed.

  6. Microfluidic high-throughput culturing of single cells for selection based on extracellular metabolite production or consumption

    OpenAIRE

    Wang, Benjamin L.; Ghaderi, Adel; Zhou, Hang; Agresti, Jeremy; David A Weitz; Fink, Gerald R; Stephanopoulos, Gregory

    2013-01-01

    Phenotyping single cells based on the products they secrete or consume is a key bottleneck in many biotechnology applications, such as combinatorial metabolic engineering for the overproduction of secreted metabolites. Here we present a flexible high-throughput approach that uses microfluidics to compartmentalize individual cells for growth and analysis in monodisperse nanoliter aqueous droplets surrounded by an immiscible fluorinated oil phase. We use this system to identify xylose-overconsu...

  7. A Stromal Cell Niche for Human and Mouse Type 3 Innate Lymphoid Cells.

    Science.gov (United States)

    Hoorweg, Kerim; Narang, Priyanka; Li, Zhi; Thuery, Anne; Papazian, Natalie; Withers, David R; Coles, Mark C; Cupedo, Tom

    2015-11-01

    Adaptive immunity critically depends on the functional compartmentalization of secondary lymphoid organs. Mesenchymal stromal cells create and maintain specialized niches that support survival, activation, and expansion of T and B cells, and integrated analysis of lymphocytes and their niche has been instrumental in understanding adaptive immunity. Lymphoid organs are also home to type 3 innate lymphoid cells (ILC3), innate effector cells essential for barrier immunity. However, a specialized stromal niche for ILC3 has not been identified. A novel lineage-tracing approach now identifies a subset of murine fetal lymphoid tissue organizer cells that gives rise exclusively to adult marginal reticular cells. Moreover, both cell types are conserved from mice to humans and colocalize with ILC3 in secondary lymphoid tissues throughout life. In sum, we provide evidence that fetal stromal organizers give rise to adult marginal reticular cells and form a dedicated stromal niche for innate ILC3 in adaptive lymphoid organs.

  8. Ultra–Short-Term Reproducibility of Speckle-Noise Freed Fluid and Tissue Compartmentalization of the Choroid Analyzed by Standard OCT

    Science.gov (United States)

    Maloca, Peter; Gyger, Cyrill; Schoetzau, Andreas; Hasler, Pascal W.

    2015-01-01

    Purpose We measured reproducibility of speckle-noise freed fluid and tissue compartmentalization of the choroid (choroidal angiography and tissue characterization). Methods This study included 26 eyes of 13 healthy females: 13 were used for repeated measurements and 13 were used for side comparison. A semiautomated algorithm removed speckle-noise with structure preservation. Results Intraclass correlation (ICC), with respect to reproducibility of the method, showed an ICC for choroidal fluid inner space analysis (FISA) of 95.15% (90.01–98.24). The ICC of tissue inner space analysis (TISA) was 99.75% (99.47–99.91). The total choroid ratio (TCR), calculated from volumes of tissue to vessels, showed an ICC of 88.84% (78.28–95.82). Comparison of eyes (left to right) showed a difference for FISA of 0.033 (95% confidence interval [CI] −0.0018–0.0680, P = 0.063), TISA −0.118 (CI −0.2373–0.0023, P = 0.055), and TCR −0.590 (CI −0.9047 to −0.2754, P = 0.004). The ICC for FISA and TISA showed a trend in the difference comparing left and right eyes; however, TCR showed a significant difference between the eyes in the measured area (P TISA was 3.45 mm3 (range, 2.38–5.0 mm3, SD 0.072). Mean TCR was 6.13 (overall range, 3.93–10.2, SD = 1.34). Conclusions Differences in choroidal layers between subjects were found mainly due to alterations in choroidal tissue. Reproducibility of speckle-noise freed choroidal angiography appeared excellent. Translational Relevance Speckle noise is a granular “noise” that appears in a wide range of medical imaging methods as ultrasonography, magnetic resonance, computer tomography, or optical coherence tomography (OCT). Findings from basic science about speckle noise were translated into a novel, medical image postprocessing application that can separate signal from speckle noise with structure preservation with high reproducibility and enhance medical imaging. PMID:26629399

  9. Fluid flow compartmentalization in the Sicilian fold and thrust belt: Implications for the regional aqueous fluid flow and oil migration history

    Science.gov (United States)

    Dewever, B.; Swennen, R.; Breesch, L.

    2013-04-01

    The fluid flow history in the frontal part of the Sicilian fold and thrust belt (FTB) has been reconstructed using an integrated structural, petrographic, geochemical and microthermometric approach. The study focused on comparing fluid flow during progressive deformation along major thrust horizons and in pelagic sediments occurring in the associated thrust sheets (foot- and hanging wall). A fluid flow model is constructed for the frontal part of the Sicilian FTB. Syn-deformational quartz and calcite have been precipitated along décollement horizons in the Iudica-Scalpello study area. The microthermometric analysis of fluid inclusions in the quartz and calcite indicated migration of low saline high temperature aqueous fluids (- 1.5 history in the thrust sheets can be subdivided into two stages. Calcite of types 1 and 2 has identical light orange cathodoluminescence as the surrounding mudstone. Furthermore, its isotope signature (2 history. Type 3 calcite is volumetrically by far the most important calcite phase. It occurs in (hydro-)fractures that are limited to the hanging wall of major thrusts and within major strike-slip faults that are interpreted as transfer faults as a result of thrust development. The presence of associated fluorite suggests more open fluid flow conditions during the final stages of the fluid flow history. Fluorite is characterized by low salinity fluid inclusions (- 2.6 < Tm < - 1.6 °C) with Th between 80 and 140 °C. Type 3 calcite has less depleted δ18O values compared to calcite of types 1 and 2 and the δ18O from calcite in faults is even positive. During the final stages of fluid flow with precipitation of calcite type 3, the fluid flow model invokes infiltration of overpressured fluids that migrated along the décollement zone. These fluids only infiltrate the thrust sheet in the hanging wall of the thrust, leading to a compartmentalized fluid flow pattern. An identical fluid flow pattern with migration of low and hot saline fluids

  10. Virtual microfluidics for digital quantification and single-cell sequencing.

    Science.gov (United States)

    Xu, Liyi; Brito, Ilana L; Alm, Eric J; Blainey, Paul C

    2016-09-01

    We have developed hydrogel-based virtual microfluidics as a simple and robust alternative to complex engineered microfluidic systems for the compartmentalization of nucleic acid amplification reactions. We applied in-gel digital multiple displacement amplification (dMDA) to purified DNA templates, cultured bacterial cells and human microbiome samples in the virtual microfluidics system, and demonstrated whole-genome sequencing of single-cell MDA products with excellent coverage uniformity and markedly reduced chimerism compared with products of liquid MDA reactions. PMID:27479330

  11. A new view into prokaryotic cell biology from electron cryotomography.

    Science.gov (United States)

    Oikonomou, Catherine M; Jensen, Grant J

    2016-04-01

    Electron cryotomography (ECT) enables intact cells to be visualized in 3D in an essentially native state to 'macromolecular' (∼4 nm) resolution, revealing the basic architectures of complete nanomachines and their arrangements in situ. Since its inception, ECT has advanced our understanding of many aspects of prokaryotic cell biology, from morphogenesis to subcellular compartmentalization and from metabolism to complex interspecies interactions. In this Review, we highlight how ECT has provided structural and mechanistic insights into the physiology of bacteria and archaea and discuss prospects for the future.

  12. Asymmetric division triggers cell-specific gene expression through coupled capture and stabilization of a phosphatase

    OpenAIRE

    Bradshaw, Niels; Losick, Richard

    2015-01-01

    Formation of a division septum near a randomly chosen pole during sporulation in Bacillus subtilis creates unequal sized daughter cells with dissimilar programs of gene expression. An unanswered question is how polar septation activates a transcription factor (σF) selectively in the small cell. We present evidence that the upstream regulator of σF, the phosphatase SpoIIE, is compartmentalized in the small cell by transfer from the polar septum to the adjacent cell pole where SpoIIE is protect...

  13. Development of droplets‐based microfluidic systems for single­‐cell high‐throughput screening

    DEFF Research Database (Denmark)

    Chen, Jun; Jensen, Thomas Glasdam; Godina, Alexei;

    2014-01-01

    investment, and a logarithmic increase to screen large combinatorial libraries over the decades also makes it gradually out of depth. Here, we are trying to develop a feasible high‐throughput system that uses microfluidics to compartmentalize a single cell for propagation and analysis in monodisperse...... picoliter aqueous droplets surround by an immiscible fluorinated oil phase. Our aim is to use this system to facilitate the screening process for both the biotechnology and food industry....

  14. A Structured Population Model of Cell Differentiation

    CERN Document Server

    Doumic, Marie; Perthame, Benoit; Zubelli, Jorge P

    2010-01-01

    We introduce and analyze several aspects of a new model for cell differentiation. It assumes that differentiation of progenitor cells is a continuous process. From the mathematical point of view, it is based on partial differential equations of transport type. Specifically, it consists of a structured population equation with a nonlinear feedback loop. This models the signaling process due to cytokines, which regulate the differentiation and proliferation process. We compare the continuous model to its discrete counterpart, a multi-compartmental model of a discrete collection of cell subpopulations recently proposed by Marciniak-Czochra et al. in 2009 to investigate the dynamics of the hematopoietic system. We obtain uniform bounds for the solutions, characterize steady state solutions, and analyze their linearized stability. We show how persistence or extinction might occur according to values of parameters that characterize the stem cells self-renewal. We also perform numerical simulations and discuss the q...

  15. Isolation of Cells Specialized in Anticancer Alkaloid Metabolism by Fluorescence-Activated Cell Sorting.

    Science.gov (United States)

    Carqueijeiro, Inês; Guimarães, Ana Luísa; Bettencourt, Sara; Martínez-Cortés, Teresa; Guedes, Joana G; Gardner, Rui; Lopes, Telma; Andrade, Cláudia; Bispo, Cláudia; Martins, Nuno Pimpão; Andrade, Paula; Valentão, Patrícia; Valente, Inês M; Rodrigues, José A; Duarte, Patrícia; Sottomayor, Mariana

    2016-08-01

    Plant specialized metabolism often presents a complex cell-specific compartmentation essential to accomplish the biosynthesis of valuable plant natural products. Hence, the disclosure and potential manipulation of such pathways may depend on the capacity to isolate and characterize specific cell types. Catharanthus roseus is the source of several medicinal terpenoid indole alkaloids, including the low-level anticancer vinblastine and vincristine, for which the late biosynthetic steps occur in specialized mesophyll cells called idioblasts. Here, the optical, fluorescence, and alkaloid-accumulating properties of C. roseus leaf idioblasts are characterized, and a methodology for the isolation of idioblast protoplasts by fluorescence-activated cell sorting is established, taking advantage of the distinctive autofluorescence of these cells. This achievement represents a crucial step for the development of differential omic strategies leading to the identification of candidate genes putatively involved in the biosynthesis, pathway regulation, and transmembrane transport leading to the anticancer alkaloids from C. roseus. PMID:27356972

  16. Flow patterns of compartmentalized anaerobic reactor%分段组合式厌氧生物反应器流态特性

    Institute of Scientific and Technical Information of China (English)

    季军远; 邢雅娟; 郑平

    2012-01-01

    厌氧生物反应器高效性与稳定性取决于其流态特性的优良,采用示踪剂脉冲刺激响应技术研究了自主研发的分段组合式厌氧生物反应器的流态,以期揭示其高效机理,便于工程化开发与应用.试验结果表明:常负荷下该反应器的流态趋于平推流;以轴向扩散模型表征,不产气与产气工况下的Peclet数分别为7.94和5.66;以多釜串联模型表征,不产气与产气工况下的串联釜数分别为4.55与3.44.高负荷与超高负荷下该反应器的流态趋于全混流,以轴向扩散模型表征,不产气与产气工况下的Peclet数分别为4.02、2.57和3.93、3.77;以多釜串联模型表征,不产气与产气工况下的串联釜数分别为2.66、2.00与2.62、2.51.反应器总死区的平均值为33.58%,其中水力死区的平均值为13.58%.建立了水力死区Vh(%)与容积水力负荷L(m3 ·m-3·d-1)和容积产气速率G (m3· m-3·d-1)之间的关联式.值得注意的是,在分段组合式厌氧反应器中,容积产气速率对水力死区的影响小于容积水力负荷.%The compartmentalized anaerobic reactor (CAR) has outstanding potential in wastewater treatment engineering. The flow patterns of CAR were investigated through pulse stimulus-response technique using sodium fluoride as tracer, and were analyzed by means of the axial dispersion (AD) model and the tanks-in-series (TIS) model. The results showed that back-mixing was small and flow pattern tended to be plug-flow at normal loading rate, Peclet numbers of AD model under the condition with or without biogas production were 5. 66 and 7. 94 respectively, N numbers of TIS model under the condition with or without biogas production were 3. 44 and 4. 55 respectively. Back-mixing was large and flow pattern tended to be completely mixed flow at high or super-high loading rate, Peclet numbers of AD model under the condition with or without biogas production were 2. 57, 4. 02 and 3. 77, 3. 93

  17. Visualization of the Nucleolus in Living Cells with Cell-Penetrating Fluorescent Peptides.

    Science.gov (United States)

    Martin, Robert M; Herce, Henry D; Ludwig, Anne K; Cardoso, M Cristina

    2016-01-01

    The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of ribosomal RNA synthesis and assembly of ribosomes. The nucleolus plays also a major role in nuclear organization as the largest compartment within the nucleus. The prominent structure of the nucleolus can be detected using contrast light microscopy providing an approximate localization of the nucleolus, but this approach does not allow to determine accurately the three-dimensional structure of the nucleolus in cells and tissues. Immunofluorescence staining with antibodies specific to nucleolar proteins albeit very useful is time consuming, normally antibodies recognize their epitopes only within a small range of species and is applicable only in fixed cells. Here, we present a simple method to selectively and accurately label this ubiquitous subnuclear compartment in living cells of a large range of species using a fluorescently labeled cell-penetrating peptide.

  18. Visualization of the Nucleolus in Living Cells with Cell-Penetrating Fluorescent Peptides.

    Science.gov (United States)

    Martin, Robert M; Herce, Henry D; Ludwig, Anne K; Cardoso, M Cristina

    2016-01-01

    The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of ribosomal RNA synthesis and assembly of ribosomes. The nucleolus plays also a major role in nuclear organization as the largest compartment within the nucleus. The prominent structure of the nucleolus can be detected using contrast light microscopy providing an approximate localization of the nucleolus, but this approach does not allow to determine accurately the three-dimensional structure of the nucleolus in cells and tissues. Immunofluorescence staining with antibodies specific to nucleolar proteins albeit very useful is time consuming, normally antibodies recognize their epitopes only within a small range of species and is applicable only in fixed cells. Here, we present a simple method to selectively and accurately label this ubiquitous subnuclear compartment in living cells of a large range of species using a fluorescently labeled cell-penetrating peptide. PMID:27576711

  19. 空气重金属元素在悬铃木叶中的亚细胞分布及其区隔化效应%Subcellular Distribution and Compartmentalization Effects of Heavy Metal Elements from Atmosphere in Platanus hispanica

    Institute of Scientific and Technical Information of China (English)

    王爱霞; 方炎明

    2011-01-01

    以南京市常见行道树二球悬铃木为试材,研究了交通繁忙区和相对清洁区道路两边悬铃木叶内6种重金属元素的亚细胞分布及其区隔化效应.结果显示:交通污染区悬铃木叶内各亚细胞组分中Cr、Cu、Ni、Pb和Zn 5种重金属元素的含量均明显高于对照区,交通空气污染是影响其含量增加的主要原因之一.相对清洁区和交通污染区5种重金属元素在悬铃木叶片、叶柄的细胞壁组分中含量最高,胞外隔离系数和污染指数均大于0.900,细胞壁是大气重金属元素重要的吸滞器官,并对重金属有明显的阻隔效应;胞内细胞器对Pb和Cu的隔离系数和污染指数最大,细胞器双层膜能在一定程度上抵御重金属元素进入细胞内.悬铃木叶片和叶柄亚细胞组分的污染指数表现为胞质组分>细胞壁组分>细胞器组分,即包括液泡液在内的胞质组分是囤积重金属元素的场所.研究表明,悬铃木叶片、叶柄各亚细胞组分对重金属均有不同程度的累积能力,叶内胞质组分的囤积作用以及细胞壁、质膜与细胞器双层膜的区隔化作用可能是悬铃木叶解除重金属元素毒害的重要原因.%Common street trees Platanus hispanica in Nanjing were used to study subcellular distribution and compartmentalization effects of six heavy metal elements (Pb,Cd,Cr,Cu,Ni and Zn) in its’ leaves on both sides of the road in the heavy traffic areas and the relatively clean area.The results showed that:The contents of 5 heavy metal elements (except Cd) in the heavy traffic areas were significantly greater than that in the relatively clean areas,which means transportation pollution was one of the major causes in increasing heavy metal element contents.5 elements accumulation (except Cd) in cell wall fractions of leaves and petioles were the highest the heavy traffic areas,and extracellular segregation coefficient and the pollution index was greater than 0

  20. Pectinous cell wall thickenings formation - A common defense strategy of plants to cope with Pb.

    Science.gov (United States)

    Krzesłowska, Magdalena; Rabęda, Irena; Basińska, Aneta; Lewandowski, Michał; Mellerowicz, Ewa J; Napieralska, Anna; Samardakiewicz, Sławomir; Woźny, Adam

    2016-07-01

    Lead, one of the most abundant and hazardous trace metals affecting living organisms, has been commonly detected in plant cell walls including some tolerant plants, mining ecotypes and hyperaccumulators. We have previously shown that in tip growing Funaria sp. protonemata cell wall is remodeled in response to lead by formation of thickenings rich in low-methylesterified pectins (pectin epitope JIM5 - JIM5-P) able to bind metal ions, which accumulate large amounts of Pb. Hence, it leads to the increase of cell wall capacity for Pb compartmentalization. Here we show that diverse plant species belonging to different phyla (Arabidopsis, hybrid aspen, star duckweed), form similar cell wall thickenings in response to Pb. These thickenings are formed in tip growing cells such as the root hairs, and in diffuse growing cells such as meristematic and root cap columella cells of root apices in hybrid aspen and Arabidopsis and in mesophyll cells in star duckweed fronds. Notably, all analyzed cell wall thickenings were abundant in JIM5-P and accumulated high amounts of Pb. In addition, the co-localization of JIM5-P and Pb commonly occurred in these cells. Hence, cell wall thickenings formed the extra compartment for Pb accumulation. In this way plant cells increased cell wall capacity for compartmentalization of this toxic metal, protecting protoplast from its toxicity. As cell wall thickenings occurred in diverse plant species and cell types differing in the type of growth we may conclude that pectinous cell wall thickenings formation is a widespread defense strategy of plants to cope with Pb. Moreover, detection of natural defense strategy, increasing plant cell walls capacity for metal accumulation, reveals a promising direction for enhancing plant efficiency in phytoremediation. PMID:27107260

  1. Pectinous cell wall thickenings formation - A common defense strategy of plants to cope with Pb.

    Science.gov (United States)

    Krzesłowska, Magdalena; Rabęda, Irena; Basińska, Aneta; Lewandowski, Michał; Mellerowicz, Ewa J; Napieralska, Anna; Samardakiewicz, Sławomir; Woźny, Adam

    2016-07-01

    Lead, one of the most abundant and hazardous trace metals affecting living organisms, has been commonly detected in plant cell walls including some tolerant plants, mining ecotypes and hyperaccumulators. We have previously shown that in tip growing Funaria sp. protonemata cell wall is remodeled in response to lead by formation of thickenings rich in low-methylesterified pectins (pectin epitope JIM5 - JIM5-P) able to bind metal ions, which accumulate large amounts of Pb. Hence, it leads to the increase of cell wall capacity for Pb compartmentalization. Here we show that diverse plant species belonging to different phyla (Arabidopsis, hybrid aspen, star duckweed), form similar cell wall thickenings in response to Pb. These thickenings are formed in tip growing cells such as the root hairs, and in diffuse growing cells such as meristematic and root cap columella cells of root apices in hybrid aspen and Arabidopsis and in mesophyll cells in star duckweed fronds. Notably, all analyzed cell wall thickenings were abundant in JIM5-P and accumulated high amounts of Pb. In addition, the co-localization of JIM5-P and Pb commonly occurred in these cells. Hence, cell wall thickenings formed the extra compartment for Pb accumulation. In this way plant cells increased cell wall capacity for compartmentalization of this toxic metal, protecting protoplast from its toxicity. As cell wall thickenings occurred in diverse plant species and cell types differing in the type of growth we may conclude that pectinous cell wall thickenings formation is a widespread defense strategy of plants to cope with Pb. Moreover, detection of natural defense strategy, increasing plant cell walls capacity for metal accumulation, reveals a promising direction for enhancing plant efficiency in phytoremediation.

  2. Recent Theoretical Approaches to Minimal Artificial Cells

    Directory of Open Access Journals (Sweden)

    Fabio Mavelli

    2014-05-01

    Full Text Available Minimal artificial cells (MACs are self-assembled chemical systems able to mimic the behavior of living cells at a minimal level, i.e. to exhibit self-maintenance, self-reproduction and the capability of evolution. The bottom-up approach to the construction of MACs is mainly based on the encapsulation of chemical reacting systems inside lipid vesicles, i.e. chemical systems enclosed (compartmentalized by a double-layered lipid membrane. Several researchers are currently interested in synthesizing such simple cellular models for biotechnological purposes or for investigating origin of life scenarios. Within this context, the properties of lipid vesicles (e.g., their stability, permeability, growth dynamics, potential to host reactions or undergo division processes… play a central role, in combination with the dynamics of the encapsulated chemical or biochemical networks. Thus, from a theoretical standpoint, it is very important to develop kinetic equations in order to explore first—and specify later—the conditions that allow the robust implementation of these complex chemically reacting systems, as well as their controlled reproduction. Due to being compartmentalized in small volumes, the population of reacting molecules can be very low in terms of the number of molecules and therefore their behavior becomes highly affected by stochastic effects both in the time course of reactions and in occupancy distribution among the vesicle population. In this short review we report our mathematical approaches to model artificial cell systems in this complex scenario by giving a summary of three recent simulations studies on the topic of primitive cell (protocell systems.

  3. Innate immune pattern recognition: a cell biological perspective.

    Science.gov (United States)

    Brubaker, Sky W; Bonham, Kevin S; Zanoni, Ivan; Kagan, Jonathan C

    2015-01-01

    Receptors of the innate immune system detect conserved determinants of microbial and viral origin. Activation of these receptors initiates signaling events that culminate in an effective immune response. Recently, the view that innate immune signaling events rely on and operate within a complex cellular infrastructure has become an important framework for understanding the regulation of innate immunity. Compartmentalization within this infrastructure provides the cell with the ability to assign spatial information to microbial detection and regulate immune responses. Several cell biological processes play a role in the regulation of innate signaling responses; at the same time, innate signaling can engage cellular processes as a form of defense or to promote immunological memory. In this review, we highlight these aspects of cell biology in pattern-recognition receptor signaling by focusing on signals that originate from the cell surface, from endosomal compartments, and from within the cytosol.

  4. A Method for Detecting Circulating Tumor Cells Based on the Measurement of Single-Cell Metabolism in Droplet-Based Microfluidics.

    Science.gov (United States)

    Del Ben, Fabio; Turetta, Matteo; Celetti, Giorgia; Piruska, Aigars; Bulfoni, Michela; Cesselli, Daniela; Huck, Wilhelm T S; Scoles, Giacinto

    2016-07-18

    The number of circulating tumor cells (CTCs) in blood is strongly correlated with the progress of metastatic cancer. Current methods to detect CTCs are based on immunostaining or discrimination of physical properties. Herein, a label-free method is presented exploiting the abnormal metabolic behavior of cancer cells. A single-cell analysis technique is used to measure the secretion of acid from individual living tumor cells compartmentalized in microfluidically prepared, monodisperse, picoliter (pL) droplets. As few as 10 tumor cells can be detected in a background of 200 000 white blood cells and proof-of-concept data is shown on the detection of CTCs in the blood of metastatic patients. PMID:27247024

  5. Modulatory effect of rRNA synthesis and ppUL83 nucleolar compartmentalization on human cytomegalovirus gene expression in vitro.

    Science.gov (United States)

    Arcangeletti, Maria-Cristina; Rodighiero, Isabella; De Conto, Flora; Gatti, Rita; Orlandini, Guido; Ferraglia, Francesca; Motta, Federica; Covan, Silvia; Razin, Sergey V; Dettori, Giuseppe; Chezzi, Carlo

    2009-10-01

    The nucleolus is a nuclear domain involved in the biogenesis of ribosomes, as well as in many other important cellular regulatory activities, such as cell cycle control and mRNA processing. Many viruses, including herpesviruses, are known to exploit the nucleolar compartment during their replication cycle. In a previous study, we demonstrated the preferential targeting and accumulation of the human cytomegalovirus (HCMV) UL83 phosphoprotein (pp65) to the nucleolar compartment and, in particular, to the nucleolar matrix of lytically infected fibroblasts; such targeting was already evident at very early times after infection. Here we have investigated the possible effects of rRNA synthesis inhibition upon the development of HCMV lytic infection, by using either actinomycin D or cisplatin at low concentrations, that are known to selectively inhibit RNA polymerase I activity, whilst leaving RNA polymerase II function unaffected. Following the inhibition of rRNA synthesis by either of the agents used, we observed a significant redistribution of nucleolar proteins within the nucleoplasm and a simultaneous depletion of viral pp65 from the nucleolus; this effect was highly evident in both unextracted cells and in nuclear matrices in situ. Of particular interest, even a brief suppression of rRNA synthesis resulted in a very strong inhibition of the progression of HCMV infection, as was concluded from the absence of accumulation of HCMV major immediate-early proteins within the nucleus of infected cells. These data suggest that a functional relationship might exist between rRNA synthesis, pp65 localization to the nucleolar matrix and the normal development of HCMV lytic infection. PMID:19585527

  6. Monodisperse Picoliter Droplets for Low-Bias and Contamination-Free Reactions in Single-Cell Whole Genome Amplification.

    Directory of Open Access Journals (Sweden)

    Yohei Nishikawa

    Full Text Available Whole genome amplification (WGA is essential for obtaining genome sequences from single bacterial cells because the quantity of template DNA contained in a single cell is very low. Multiple displacement amplification (MDA, using Phi29 DNA polymerase and random primers, is the most widely used method for single-cell WGA. However, single-cell MDA usually results in uneven genome coverage because of amplification bias, background amplification of contaminating DNA, and formation of chimeras by linking of non-contiguous chromosomal regions. Here, we present a novel MDA method, termed droplet MDA, that minimizes amplification bias and amplification of contaminants by using picoliter-sized droplets for compartmentalized WGA reactions. Extracted DNA fragments from a lysed cell in MDA mixture are divided into 105 droplets (67 pL within minutes via flow through simple microfluidic channels. Compartmentalized genome fragments can be individually amplified in these droplets without the risk of encounter with reagent-borne or environmental contaminants. Following quality assessment of WGA products from single Escherichia coli cells, we showed that droplet MDA minimized unexpected amplification and improved the percentage of genome recovery from 59% to 89%. Our results demonstrate that microfluidic-generated droplets show potential as an efficient tool for effective amplification of low-input DNA for single-cell genomics and greatly reduce the cost and labor investment required for determination of nearly complete genome sequences of uncultured bacteria from environmental samples.

  7. Regulation of Cytoplasmic and Vacuolar Volumes by Plant Cells in Suspension Culture

    DEFF Research Database (Denmark)

    Owens, Trevor; Poole, Ronald J

    1979-01-01

    Quantitative microscopical measurements have been made of the proportion of cell volume occupied by cytoplasm in a cell suspension culture derived from cotyledons of bush bean (cv. Contender). On a 7-day culture cycle, the content of cytoplasm varies from 25% at the time of transfer to 45% at the...... start of the phase of rapid cell division. If the culture is continued beyond 7 days, the vacuole volume reaches 90% of cell volume by day 12.Attempts to measure relative cytoplasmic volumes by compartmental analysis of nonelectrolyte efflux were unsuccessful. The proportion of cell volume occupied by...... cytoplasm is roughly correlated with protein content, but shows no correlation with cell size or with intracellular concentrations of K or Na. The most striking observation is that the growth of cytoplasmic volume for the culture as a whole appears to be constant throughout the culture cycle, despite...

  8. Compartmentalization of membrane trafficking, glucose transport, glycolysis, actin, tubulin and the proteasome in the cytoplasmic droplet/Hermes body of epididymal sperm.

    Science.gov (United States)

    Au, Catherine E; Hermo, Louis; Byrne, Elliot; Smirle, Jeffrey; Fazel, Ali; Kearney, Robert E; Smith, Charles E; Vali, Hojatollah; Fernandez-Rodriguez, Julia; Simon, Paul H G; Mandato, Craig; Nilsson, Tommy; Bergeron, John J M

    2015-08-01

    Discovered in 1909 by Retzius and described mainly by morphology, the cytoplasmic droplet of sperm (renamed here the Hermes body) is conserved among all mammalian species but largely undefined at the molecular level. Tandem mass spectrometry of the isolated Hermes body from rat epididymal sperm characterized 1511 proteins, 43 of which were localized to the structure in situ by light microscopy and two by quantitative electron microscopy localization. Glucose transporter 3 (GLUT-3) glycolytic enzymes, selected membrane traffic and cytoskeletal proteins were highly abundant and concentrated in the Hermes body. By electron microscope gold antibody labelling, the Golgi trafficking protein TMED7/p27 localized to unstacked flattened cisternae of the Hermes body, as did GLUT-3, the most abundant protein. Its biogenesis was deduced through the mapping of protein expression for all 43 proteins during male germ cell differentiation in the testis. It is at the terminal step 19 of spermiogenesis that the 43 characteristic proteins accumulated in the nascent Hermes body. PMID:26311421

  9. Fabrication of pixilated architecture large panel organic flexible solar cell by reducing bulk electrical resistance

    Science.gov (United States)

    Panag, Jasmeet Singh

    This study investigates experimentally the photovoltaic behavior and performance of a new pixilated architecture of large organic photovoltaic panels made of a large array of high-aspect ratio three-dimensional pillars surrounded by a matrix of polymer photoactive material. A least addressed problem in organic and thin-film solar cells is the high bulk resistance of cathodic and anodic layers that result in drastic reduction of currents and power conversion efficiency (PCE). For such panels to be practical and commercially competitive, this huge bulk-resistance has to be minimized as much as possible. In this study, therefore, we introduce a new novel architecture that essentially compartmentalizes large panels into smaller modules that are connected to each other in a parallel fashion. In this architecture, the metal cathode layer is applied on the top as a series of lines whereas the anodic layer is independently connected to the pixilated cells at the bottom. As a result, these modules act like independent pixel cells wherein the damage from process and operation is limited individual pixel cells. The factors considered in validating the pixilated architecture presented here consisted of effect of number of pixels on efficiency and bulk electrical resistance. In addition, the study shows that pixilated architecture offers more uniform photoactive layers, and hence better photovoltaic performance because of the compartmentalization.

  10. Suofu Qin’s work on studies of cell survival signaling in cancer and epithelial cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Reactive oxygen species (ROS) encompass a variety of diverse chemical species including superoxide anions, hydrogen peroxide, hydroxyl radicals and peroxynitrite, which are mainly produced via mitochondrial oxidative metabolism, enzymatic reactions, and light-initiated lipid peroxidation. Over-production of ROS and/or decrease in the antioxidant capacity cause cells to undergo oxi- dative stress that damages cellular macromolecules such as proteins, lipids, and DNA. Oxidative stress is associated with ageing and the development of agerelated diseases such as cancer and age-related macular degeneration. ROS activate signaling pathways that promote cell survival or lead to cell death, depending on the source and site of ROS production, the specific ROS generated, the concentration and kinetics of ROS generation, and the cell types being challenged. However, how the nature and compartmentalization of ROS contribute to the pathogenesis of individual diseases is poorly understood. Consequently, it is crucial to gain a comprehensive understanding of the molecular bases of cell oxidative stress signaling, which will then provide novel therapeutic opportunities to interfere with disease progression via targeting specific signaling pathways.Currently, Dr. Qin’s work is focused on inflammatory and oxidative stress responses using the retinal pigment epithelial (RPE) cells as a model. The study of RPE cell inflammatory and oxidative stress responses has successfully led to a better understanding of RPE cell biology and identification of potential therapeutic targets.

  11. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration.

    Directory of Open Access Journals (Sweden)

    Sang Goo Lee

    Full Text Available Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration.

  12. Myc and Fgf Are Required for Zebrafish Neuromast Hair Cell Regeneration

    Science.gov (United States)

    Obholzer, Nikolaus D.; Sun, Shan; Li, Wenyan; Petrillo, Marco; Dai, Pu; Zhou, Yi; Cotanche, Douglas A.; Megason, Sean G.; Li, Huawei; Chen, Zheng-Yi

    2016-01-01

    Unlike mammals, the non-mammalian vertebrate inner ear can regenerate the sensory cells, hair cells, either spontaneously or through induction after hair cell loss, leading to hearing recovery. The mechanisms underlying the regeneration are poorly understood. By microarray analysis on a chick model, we show that chick hair cell regeneration involves the activation of proliferation genes and downregulation of differentiation genes. Both MYC and FGF are activated in chick hair cell regeneration. Using a zebrafish lateral line neuromast hair cell regeneration model, we show that the specific inhibition of Myc or Fgf suppresses hair cell regeneration, demonstrating that both pathways are essential to the process. Rapid upregulation of Myc and delayed Fgf activation during regeneration suggest a role of Myc in proliferation and Fgf in differentiation. The dorsal-ventral pattern of fgfr1a in the neuromasts overlaps with the distribution of hair cell precursors. By laser ablation, we show that the fgfr1a-positive supporting cells are likely the hair cell precursors that directly give rise to new hair cells; whereas the anterior-posterior fgfr1a-negative supporting cells have heightened proliferation capacity, likely to serve as more primitive progenitor cells to replenish lost precursors after hair cell loss. Thus fgfr1a is likely to mark compartmentalized supporting cell subtypes with different capacities in renewal proliferation and hair cell regeneration. Manipulation of c-MYC and FGF pathways could be explored for mammalian hair cell regeneration. PMID:27351484

  13. Compartmentalization and Transport in Synthetic Vesicles

    OpenAIRE

    Schmitt, Christine; Lippert, Anna H.; Bonakdar, Navid; Sandoghdar, Vahid; Voll, Lars M

    2016-01-01

    Nanoscale vesicles have become a popular tool in life sciences. Besides liposomes that are generated from phospholipids of natural origin, polymersomes fabricated of synthetic block copolymers enjoy increasing popularity, as they represent more versatile membrane building blocks that can be selected based on their specific physicochemical properties, such as permeability, stability, or chemical reactivity. In this review, we focus on the application of simple and nested artificial vesicles in...

  14. Reactive oxygen species and redox compartmentalization

    OpenAIRE

    Kaludercic, Nina; Deshwal, Soni; Di Lisa, Fabio

    2014-01-01

    Reactive oxygen species (ROS) formation and signaling are of major importance and regulate a number of processes in physiological conditions. A disruption in redox status regulation, however, has been associated with numerous pathological conditions. In recent years it has become increasingly clear that oxidative and reductive modifications are confined in a spatio-temporal manner. This makes ROS signaling similar to that of Ca2+ or other second messengers. Some subcellular compartments are m...

  15. Review of compartmental analysis in ecosystem science

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, R.V.

    1978-01-01

    The compartment model has a large number of applications in ecosystem science. An attempt is made to outline the problem areas and objectives for which this type of model has particular advantages. The areas identified are an adequate model of tracer movement through an undisturbed but non-equilibrium ecosystem; an adequate model of the movement of material in greater than tracer quantity through an ecosystem near steady state; a minimal model based on limited data; a tool for extrapolating past trends; a framework for the summarization of large data sets; and a theoretical tool for exploring and comparing limited aspects of ecosystem dynamics. The review is set in an historical perspective which helps explain why these models were adopted in ecology. References are also provided to literature which documents available mathematical techniques in an ecological context.

  16. Compartmentalization analysis using discrete fracture network models

    Energy Technology Data Exchange (ETDEWEB)

    La Pointe, P.R.; Eiben, T.; Dershowitz, W. [Golder Associates, Redmond, VA (United States); Wadleigh, E. [Marathon Oil Co., Midland, TX (United States)

    1997-08-01

    This paper illustrates how Discrete Fracture Network (DFN) technology can serve as a basis for the calculation of reservoir engineering parameters for the development of fractured reservoirs. It describes the development of quantitative techniques for defining the geometry and volume of structurally controlled compartments. These techniques are based on a combination of stochastic geometry, computational geometry, and graph the theory. The parameters addressed are compartment size, matrix block size and tributary drainage volume. The concept of DFN models is explained and methodologies to compute these parameters are demonstrated.

  17. Programmed cell death during development of cowpea (Vigna unguiculata (L.) Walp.) seed coat.

    Science.gov (United States)

    Lima, Nathália Bastos; Trindade, Fernanda Gomes; da Cunha, Maura; Oliveira, Antônia Elenir Amâncio; Topping, Jennifer; Lindsey, Keith; Fernandes, Kátia Valevski Sales

    2015-04-01

    The seed coat develops primarily from maternal tissues and comprises multiple cell layers at maturity, providing a metabolically dynamic interface between the developing embryo and the environment during embryogenesis, dormancy and germination of seeds. Seed coat development involves dramatic cellular changes, and the aim of this research was to investigate the role of programmed cell death (PCD) events during the development of seed coats of cowpea [Vigna unguiculata (L.) Walp.]. We demonstrate that cells of the developing cowpea seed coats undergo a programme of autolytic cell death, detected as cellular morphological changes in nuclei, mitochondria, chloroplasts and vacuoles, DNA fragmentation and oligonucleosome accumulation in the cytoplasm, and loss of membrane viability. We show for the first time that classes 6 and 8 caspase-like enzymes are active during seed coat development, and that these activities may be compartmentalized by translocation between vacuoles and cytoplasm during PCD events. PMID:25142352

  18. Heparan Sulfate Proteoglycans Regulate Fgf Signaling and Cell Polarity during Collective Cell Migration

    Directory of Open Access Journals (Sweden)

    Marina Venero Galanternik

    2015-01-01

    Full Text Available Collective cell migration is a highly regulated morphogenetic movement during embryonic development and cancer invasion that involves the precise orchestration and integration of cell-autonomous mechanisms and environmental signals. Coordinated lateral line primordium migration is controlled by the regulation of chemokine receptors via compartmentalized Wnt/β-catenin and fibroblast growth factor (Fgf signaling. Analysis of mutations in two exostosin glycosyltransferase genes (extl3 and ext2 revealed that loss of heparan sulfate (HS chains results in a failure of collective cell migration due to enhanced Fgf ligand diffusion and loss of Fgf signal transduction. Consequently, Wnt/β-catenin signaling is activated ectopically, resulting in the subsequent loss of the chemokine receptor cxcr7b. Disruption of HS proteoglycan (HSPG function induces extensive, random filopodia formation, demonstrating that HSPGs are involved in maintaining cell polarity in collectively migrating cells. The HSPGs themselves are regulated by the Wnt/β-catenin and Fgf pathways and thus are integral components of the regulatory network that coordinates collective cell migration with organ specification and morphogenesis.

  19. Multipotent capacity of immortalized human bronchial epithelial cells.

    Directory of Open Access Journals (Sweden)

    Oliver Delgado

    Full Text Available While the adult murine lung utilizes multiple compartmentally restricted progenitor cells during homeostasis and repair, much less is known about the progenitor cells from the human lung. Translating the murine stem cell model to humans is hindered by anatomical differences between species. Here we show that human bronchial epithelial cells (HBECs display characteristics of multipotent stem cells of the lung. These HBECs express markers indicative of several epithelial types of the adult lung when experimentally tested in cell culture. When cultured in three different three-dimensional (3D systems, subtle changes in the microenvironment result in unique responses including the ability of HBECs to differentiate into multiple central and peripheral lung cell types. These new findings indicate that the adult human lung contains a multipotent progenitor cell whose differentiation potential is primarily dictated by the microenvironment. The HBEC system is not only important in understanding mechanisms for specific cell lineage differentiation, but also for examining changes that correlate with human lung diseases including lung cancer.

  20. Epigenetic remodeling in B-cell acute lymphoblastic leukemia occurs in two tracks and employs embryonic stem cell-like signatures.

    Science.gov (United States)

    Lee, Seung-Tae; Muench, Marcus O; Fomin, Marina E; Xiao, Jianqiao; Zhou, Mi; de Smith, Adam; Martín-Subero, José I; Heath, Simon; Houseman, E Andres; Roy, Ritu; Wrensch, Margaret; Wiencke, John; Metayer, Catherine; Wiemels, Joseph L

    2015-03-11

    We investigated DNA methylomes of pediatric B-cell acute lymphoblastic leukemias (B-ALLs) using whole-genome bisulfite sequencing and high-definition microarrays, along with RNA expression profiles. Epigenetic alteration of B-ALLs occurred in two tracks: de novo methylation of small functional compartments and demethylation of large inter-compartmental backbones. The deviations were exaggerated in lamina-associated domains, with differences corresponding to methylation clusters and/or cytogenetic groups. Our data also suggested a pivotal role of polycomb and CTBP2 in de novo methylation, which may be traced back to bivalency status of embryonic stem cells. Driven by these potent epigenetic modulations, suppression of polycomb target genes was observed along with disruption of developmental fate and cell cycle and mismatch repair pathways and altered activities of key upstream regulators.

  1. Antigen-Specific Th17 Cells Are Primed by Distinct and Complementary Dendritic Cell Subsets in Oropharyngeal Candidiasis.

    Directory of Open Access Journals (Sweden)

    Kerstin Trautwein-Weidner

    2015-10-01

    Full Text Available Candida spp. can cause severe and chronic mucocutaneous and systemic infections in immunocompromised individuals. Protection from mucocutaneous candidiasis depends on T helper cells, in particular those secreting IL-17. The events regulating T cell activation and differentiation toward effector fates in response to fungal invasion in different tissues are poorly understood. Here we generated a Candida-specific TCR transgenic mouse reactive to a novel endogenous antigen that is conserved in multiple distant species of Candida, including the clinically highly relevant C. albicans and C. glabrata. Using TCR transgenic T cells in combination with an experimental model of oropharyngeal candidiasis (OPC we investigated antigen presentation and Th17 priming by different subsets of dendritic cells (DCs present in the infected oral mucosa. Candida-derived endogenous antigen accesses the draining lymph nodes and is directly presented by migratory DCs. Tissue-resident Flt3L-dependent DCs and CCR2-dependent monocyte-derived DCs collaborate in antigen presentation and T cell priming during OPC. In contrast, Langerhans cells, which are also present in the oral mucosa and have been shown to prime Th17 cells in the skin, are not required for induction of the Candida-specific T cell response upon oral challenge. This highlights the functional compartmentalization of specific DC subsets in different tissues. These data provide important new insights to our understanding of tissue-specific antifungal immunity.

  2. Inferring maps of forces inside cell membrane microdomains

    CERN Document Server

    Masson, J -B; Tuerkcan, S; Voisinne, G; Popoff, M R; Vergassola, M; Alexandrou, A

    2015-01-01

    Mapping of the forces on biomolecules in cell membranes has spurred the development of effective labels, e.g. organic fluorophores and nanoparticles, to track trajectories of single biomolecules. Standard methods use particular statistics, namely the mean square displacement, to analyze the underlying dynamics. Here, we introduce general inference methods to fully exploit information in the experimental trajectories, providing sharp estimates of the forces and the diffusion coefficients in membrane microdomains. Rapid and reliable convergence of the inference scheme is demonstrated on trajectories generated numerically. The method is then applied to infer forces and potentials acting on the receptor of the $\\epsilon$-toxin labeled by lanthanide-ion nanoparticles. Our scheme is applicable to any labeled biomolecule and results show show its general relevance for membrane compartmentation.

  3. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  4. Golgi-mediated synthesis and secretion of matrix polysaccharides of the primary cell wall of higher plants.

    Directory of Open Access Journals (Sweden)

    Azeddine eDriouich

    2012-04-01

    Full Text Available The Golgi apparatus of eukaryotic cells is known for its central role in the processing, sorting and transport of proteins to intra- and extracellular compartments. In plants, it has the additional task of assembling and exporting the non-cellulosic polysaccharides of the cell wall matrix including pectin and hemicelluloses, which are important for plant development and protection. In this review, we focus on the biosynthesis of complex polysaccharides of the primary cell wall. We present and discuss the compartmental organization of the Golgi stacks with regards to complex polysaccharides assembly and secretion using immuno-electron microscopy and specific antibodies recognizing various sugar epitopes. We also discuss the significance of the recently identified Golgi-localized glycosyltransferases that are responsible for the biosynthesis of complex polysaccharides of the primary cell wall matrix.

  5. Studying the Nucleated Mammalian Cell Membrane by Single Molecule Approaches

    Science.gov (United States)

    Wang, Feng; Wu, Jiazhen; Gao, Jing; Liu, Shuheng; Jiang, Junguang; Jiang, Shibo; Wang, Hongda

    2014-01-01

    The cell membrane plays a key role in compartmentalization, nutrient transportation and signal transduction, while the pattern of protein distribution at both cytoplasmic and ectoplasmic sides of the cell membrane remains elusive. Using a combination of single-molecule techniques, including atomic force microscopy (AFM), single molecule force spectroscopy (SMFS) and stochastic optical reconstruction microscopy (STORM), to study the structure of nucleated cell membranes, we found that (1) proteins at the ectoplasmic side of the cell membrane form a dense protein layer (4 nm) on top of a lipid bilayer; (2) proteins aggregate to form islands evenly dispersed at the cytoplasmic side of the cell membrane with a height of about 10–12 nm; (3) cholesterol-enriched domains exist within the cell membrane; (4) carbohydrates stay in microdomains at the ectoplasmic side; and (5) exposed amino groups are asymmetrically distributed on both sides. Based on these observations, we proposed a Protein Layer-Lipid-Protein Island (PLLPI) model, to provide a better understanding of cell membrane structure, membrane trafficking and viral fusion mechanisms. PMID:24806512

  6. Effects of potentially acidic air pollutants on the intracellular distribution and transport of plant growth regulators in mesophyll cells of leaves. Consequences on stress- and developmental physiology

    Energy Technology Data Exchange (ETDEWEB)

    Kremer, H.; Pfanz, H.; Hartung, W.

    1987-07-11

    The influence of SO/sub 2/ on the intracellular distribution of abscisic acid (ABA) and indole-acetic acid (IAA) in mesophyll cells of Picea abies, Tsuga americana and Hordeum vulgare was investigated. The compartmentation of ABA and IAA depends on intracellular pH-gradients. The hydrophilic anions ABA and IAA are accumulated in the alkaline cell compartments cytosol and chloroplasts, which act as anion traps for weak acids. Uptake of sulfur dioxide into leaves leads to an acidification of alkaline cell compartments, thus decreasing intracellular pH-gradients. Consequently this results in an increased release of plant growth regulators from the cell interior into the apoplast. Therefore the target cells of plant hormones i.e. meristems and stomates are exposed to altered hormone concentrations. Obviously this influences the regulation of cellular metabolism plant development and growth.

  7. The Endoplasmic Reticulum: A Social Network in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Jun Chen; Caitlin Doyle; Xingyun Qi; Huanquan Zheng

    2012-01-01

    The endoplasmic reticulum (ER) is an interconnected network comprised of ribosome-studded sheets and smooth tubules.The ER plays crucial roles in the biosynthesis and transport of proteins and lipids,and in calcium (Ca2+) regulation in compartmentalized eukaryotic cells including plant cells.To support its well-segregated functions,the shape of the ER undergoes notable changes in response to both developmental cues and outside influences.In this review,we will discuss recent findings on molecular mechanisms underlying the unique morphology and dynamics of the ER,and the importance of the interconnected ER network in cell polarity.In animal and yeast cells,two family proteins,the reticulons and DP1/Yop1,are required for shaping high-curvature ER tubules,while members of the atlastin family of dynamin-like GTPases are involved in the fusion of ER tubules to make an interconnected ER network.In plant cells,recent data also indicate that the reticulons are involved in shaping ER tubules,while RHD3,a plant member of the atlastin GTPases,is required for the generation of an interconnected ER network.We will also summarize the current knowledge on how the ER interacts with other membrane-bound organelles,with a focus on how the ER and Golgi interplay in plant cells.

  8. Microfluidic co-culture platform to quantify chemotaxis of primary stem cells.

    Science.gov (United States)

    Tatárová, Z; Abbuehl, J P; Maerkl, S; Huelsken, J

    2016-05-21

    Functional analysis of primary tissue-specific stem cells is hampered by their rarity. Here we describe a greatly miniaturized microfluidic device for the multiplexed, quantitative analysis of the chemotactic properties of primary, bone marrow-derived mesenchymal stem cells (MSC). The device was integrated within a fully customized platform that both increased the viability of stem cells ex vivo and simplified manipulation during multidimensional acquisition. Since primary stem cells can be isolated only in limited number, we optimized the design for efficient cell trapping from low volume and low concentration cell suspensions. Using nanoliter volumes and automated microfluidic controls for pulsed medium supply, our platform is able to create stable gradients of chemoattractant secreted from mammalian producer cells within the device, as was visualized by a secreted NeonGreen fluorescent reporter. The design was functionally validated by a CXCL/CXCR ligand/receptor combination resulting in preferential migration of primary, non-passaged MSC. Stable gradient formation prolonged assay duration and resulted in enhanced response rates for slowly migrating stem cells. Time-lapse video microscopy facilitated determining a number of migratory properties based on single cell analysis. Jackknife-resampling revealed that our assay requires only 120 cells to obtain statistically significant results, enabling new approaches in the research on rare primary stem cells. Compartmentalization of the device not only facilitated such quantitative measurements but will also permit future, high-throughput functional screens. PMID:27137768

  9. The Early Results for the Treatment of Medial Compartmental Knee Osteoarthritis:Unicompart-mental Knee Arthroplasty(Oxford Ⅲ)Versus Total Knee Arthroplasty%单髁置换与全膝关节置换治疗内侧胫股关节炎早中期疗效比较

    Institute of Scientific and Technical Information of China (English)

    房小文; 薛峰; 盛晓文; 王正飞; 杨兴

    2015-01-01

    目的:比较Oxford Ⅲ代单髁置换( unicompartmental knee arthroplasty,UkA)和全膝关节置换术( total knee artgroplasty,TkA)治疗膝关节内侧胫股关节炎的早期疗效。方法2013年4月至2014年8月我院收治内侧胫股关节炎患者31例32膝,UkA组15例16膝,TkA组16例16膝。术前对UkA组和TkA组患者膝关节的功能评价采用膝关节评分( keen society score,kSS),分别为55.94分和56.47分;美国特种外科医院膝关节评分( hospital for special sur-gery knee score,HSS)分别为57.25分和59.37分;分别进行单髁置换和全膝关节置换。结果两组患者术后2周的功能改善情况UkA组较TkA组好,膝关节活动度更大;两组的手术时间UkA组较TkA组短。结论人工单髁置换治疗膝内侧胫股关节炎是一种行之有效的方法,与全膝置换早期效果类似,但手术时间短,恢复快。%Objective To investigate the early resuit of unicompartmental knee arthroplasty( OxfordⅢ)versus total knee arthroplasty for the treatment of medial compartmental knee osteoarthritis. Methods From April 2013 to August 2014,15 ca-ses(16 knee)of medial compartmental knee osteoarthritis were treated by unicompartmental knee arthroplasty(OxfordⅢ),16 cases(16 knee)of medial compartmental knee osteoarthritis were treated by total knee arthroplasty. The UkA group and TkA group hospital for special surgery knee score(HSS)were 57. 25 and 59. 37 respectively;keen Society Score(kSS)were 55. 94 and 56. 47 respectively. Results All the patients′data were collected. By the time of 2 weeks after operation,Patients in the group UkA had better results than group TkA in the range of motion( ROM),kSS,HSS and the operation time. Conclusion With the strict indications selection,UkA for the treatment of medial compartmental knee osteoarthritis is comparable to TkA, and has less time for operation,rapid postoperative recovery than TkA.

  10. The dynamics of p53 in single cells: physiologically based ODE and reaction-diffusion PDE models

    Science.gov (United States)

    Eliaš, Ján; Dimitrio, Luna; Clairambault, Jean; Natalini, Roberto

    2014-08-01

    The intracellular signalling network of the p53 protein plays important roles in genome protection and the control of cell cycle phase transitions. Recently observed oscillatory behaviour in single cells under stress conditions has inspired several research groups to simulate and study the dynamics of the protein with the aim of gaining a proper understanding of the physiological meanings of the oscillations. We propose compartmental ODE and PDE models of p53 activation and regulation in single cells following DNA damage and we show that the p53 oscillations can be retrieved by plainly involving p53-Mdm2 and ATM-p53-Wip1 negative feedbacks, which are sufficient for oscillations experimentally, with no further need to introduce any delays into the protein responses and without considering additional positive feedback.

  11. Nano thermo-hydrodynamics method for investigating cell membrane fluidity

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    As a barrier to compartmentalize cells,mem-branes form the interface between a cell and its surround-ings.The essential function of a membrane is to maintain a relatively stable environment in the cell,exchange sub-stances selectively and transfer energy and information continually from the outside.It is intriguing that above the phase transition temperature,the membrane lipid molecule will have three modes-lateral diffusion,rotational movement and flip-flop activity.These thermodynamic processes are vital to cell existence,growth,division,differentiation and are also responsible for hundreds of thousands of phenomena in life.Previously,species transport across the membrane was interpreted mainly from a phenomenological view using a lumped system model.Therefore,detailed flow processes occurred in the membrane domain and clues related to life mechanism were not sufficiently tackled.Such important issues can be clarifled by modeling nano scale thermal hydrodynamics over the gap space of a cell membrane.Previously observed complex membrane behaviors will be shown in this paper and explained by the thermally induced fluidic convections inside the membrane.A correlation between nano scale hydrodynamics,non-equilibrium thermodynamics and eell membrane activities is set up.The disclosed mechanisms are expected to provide a new viewpoint on the interaction between intracellular and extracellular processes through the membrane.

  12. SSeCKS, a Major Protein Kinase C Substrate with Tumor Suppressor Activity, Regulates G1→S Progression by Controlling the Expression and Cellular Compartmentalization of Cyclin D

    OpenAIRE

    Lin, Xueying; Nelson, Peter; Gelman, Irwin H.

    2000-01-01

    SSeCKS, first isolated as a G1→S inhibitor that is downregulated in src- and ras-transformed cells, is a major cytoskeleton-associated PKC substrate with tumor suppressor and kinase-scaffolding activities. Previous attempts at constitutive expression resulted in cell variants with truncated ectopic SSeCKS products. Here, we show that tetracycline-regulated SSeCKS expression in NIH 3T3 cells induces G1 arrest marked by extracellular signal-regulated kinase 2-dependent decreases in cyclin D1 ex...

  13. Membrane potential and ion transport in lung epithelial type II cells

    International Nuclear Information System (INIS)

    The alveolar type II pneumocyte is critically important to the function and maintenance of pulmonary epithelium. To investigate the nature of the response of type II cells to membrane injury, and describe a possible mechanism by which these cells regulate surfactant secretion, the membrane potential of isolated rabbit type II cells was characterized. This evaluation was accomplished by measurements of the accumulation of the membrane potential probes: [3H]triphenylmethylphosphonium ([3H]TPMP+), rubidium 86, and the fluorescent dye DiOC5. A compartmental analysis of probe uptake into mitochondrial, cytoplasmic, and non-membrane potential dependent stores was made through the use of selective membrane depolarizations with carbonycyanide M-chlorophenylhydrazone (CCCP), and lysophosphatidylcholine (LPC). These techniques and population analysis with flow cytometry, permitted the accurate evaluation of type II cell membrane potential under control conditions and under conditions which stimulated cell activity. Further analysis of ion transport by cells exposed to radiation or adrenergic stimulation revealed a common increase in Na+/K+ ATPase activity, and an increase in sodium influx across the plasma membrane. This sodium influx was found to be a critical step in the initiation of surfactant secretion. It is concluded that radiation exposure as well as other pulmonary toxicants can directly affect the membrane potential and ionic regulation of type II cells. Ion transport, particularly of sodium, plays an important role in the regulation of type II cell function

  14. Spatially Controlled Delivery of siRNAs to Stem Cells in Implants Generated by Multi-Component Additive Manufacturing

    DEFF Research Database (Denmark)

    Andersen, Morten Østergaard; Le, Dang Quang Svend; Chen, Muwan;

    2013-01-01

    Additive manufacturing is a promising technique in tissue engineering, as it enables truly individualized implants to be made to fit a particular defect. As previously shown, a feasible strategy to produce complex multicellular tissues is to deposit different small interfering RNA (siRNA) in porous...... implants that are subsequently sutured together. In this study, an additive manufacturing strategy to deposit carbohydrate hydrogels containing different siRNAs is applied into an implant, in a spatially controlled manner. When the obtained structures are seeded with mesenchymal stem (stromal) cells......, the selected siRNAs are delivered to the cells and induces specific and localized gene silencing. Here, it is demonstrated how to replicate part of a patient's spinal cord from a computed tomography scan, using an additive manufacturing technique to produce an implant with compartmentalized si...

  15. Characterization of CD8+ T-Cell Responses in the Peripheral Blood and Skin Injection Sites of Melanoma Patients Treated with mRNA Electroporated Autologous Dendritic Cells (TriMixDC-MEL

    Directory of Open Access Journals (Sweden)

    Daphné Benteyn

    2013-01-01

    Full Text Available Treatment of melanoma patients with mRNA electroporated dendritic cells (TriMixDC-MEL stimulates T-cell responses against the presented tumor-associated antigens (TAAs. In the current clinical trials, melanoma patients with systemic metastases are treated, requiring priming and/or expansion of preexisting TAA-specific T cells that are able to migrate to both the skin and internal organs. We monitored the presence of TAA-specific CD8+ T cells infiltrating the skin at sites of intradermal TriMixDC-MEL injection (SKILs and within the circulation of melanoma patients treated in two clinical trials. In 10 out of fourteen (71% patients screened, CD8+ T cells recognizing any of the four TAA presented by TriMixDC-MEL cellular vaccine were found in both compartments. In total, 30 TAA-specific T-cell responses were detected among the SKILs and 29 among peripheral blood T cells, of which 24 in common. A detailed characterization of the antigen specificity of CD8+ T-cell populations in four patients indicates that the majority of the epitopes detected were only recognized by CD8+ T cells derived from either skin biopsies or peripheral blood, indicating that some compartmentalization occurs after TriMix-DC therapy. To conclude, functional TAA-specific CD8+ T cells distribute both to the skin and peripheral blood of patients after TriMixDC-MEL therapy.

  16. A new role for T cells in dampening innate inflammatory responses

    Institute of Scientific and Technical Information of China (English)

    TANG Hong; FU YangXin

    2010-01-01

    @@ The inflammatory response is an attempt by a host to protect itself against injurious stimuli and initiate the tissue healing process [1,2].Although the production of both proand anti-inflammatory mediators which occurs mainly within tissues is a systemic process, the pathophysiological events of inflammation are usually compartmentalized, being different from organ to organ, and between organs and the peripheral blood [3,4].Inflammation and consequential tissue injury vary according to the nature of the insults (e.g.burns, hemorrhages, trauma, peritonitis), the cellular composition of each tissue (e.g.the types of phagocytes or endothelial cells), the micro-environment (e.g.the localized presence of GM-CSF in the lungs, low levels of arginine in the liver, presence of endotoxins in the gut), and different modes of leukocyte recruitment.

  17. On the Essence of Key Words and Concepts of Zoning and Compartmentalization inTerrestrial Animal Health Code%《陆生动物卫生法典》区域化管理标准中关键词汇和概念的理解与把握

    Institute of Scientific and Technical Information of China (English)

    葛林; 孙研

    2016-01-01

    OIE is the WTO reference organization for standards relating to animal health and zoonoses. OIE Terrestrial Animal Health Code sets out standards for the improvement of animal health and veterinary public health worldwide,as well as standards for safe international trade in terrestrial animals and their products. The standards of zoning and compartmentalization are widely applied in recent years across the globe. In China,significant progress has been made in the study of zoning and compartmentalization,with great achievement made in practice meanwhile. This article made analysis on key words and key principles in provisions of zoning and compartmentalization,the results of which suggested that with regard to control policies for domestic animal diseases,we should make full use of zoning management approaches,and apply various measures addressing issues at the level of species,farm and a whole zone in order to gradually put animal diseases under control and achieve clean-up status for certain diseases by taking the experiences gained from one place and popularizing it in the whole area. As for risk prevention policies of exotic animal diseases,results of this study revealed that the basic strategy should be to set up“risk buffer zones”along our borders and build“quarantine zones”in our neighboring countries.%世界动物卫生组织(OIE)是世界贸易组织(WTO)合作制定动物卫生和人兽共患病防控技术标准的权威机构,其标准对于各成员科学控制动物疫病、有效保障动物和动物产品正常国际贸易具有重要的指导意义。近些年,OIE区域化标准在各国得到了广泛应用。我国在区域化管理政策研究和实际应用等方面也都取得了很大进展。本文重点分析了《陆生动物卫生法典》区域化章节的关键词汇和概念,提示我们对于国内本土动物疫病,在防治策略上,应充分运用区域化管理措施,从“种、场、区”三个层次

  18. Lyophilized kits of diamino dithiol compounds for labelling with {sup 99m}-technetium. Pharmacokinetics studies and distribution compartmental models of the related complexes; Conjuntos de reativos liofilizados de compostos diaminoditiolicos para marcacao com tecnecio-99m. Estudo farmacocinetico e elaboracao de modelos compartimentalizados dos respectivos complexos

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, Elaine Bortoleti de

    1995-07-01

    The present work reflects the clinical interest for labelling diamino dithiol compounds with technetium-99m. Both chosen compounds, L,L-Ethylene dicysteine (L,L-EC) and L,L-Ethylene dicysteine diethyl esther (L,L-ECD) were obtained with relative good yield and characterized by IR and NMR. The study of labelling conditions with technetium-99m showed the influence of the type and mass of reducing agent as well as the pH on the formation of complexes with desired biological characteristics. Radiochemical purity was determined by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Lyophilised kits of L,L-EC and L,L-ECD for labelling with {sup 99m}Tc were obtained, with stability superior to 120 days, when stored under refrigeration, enabling the kits marketing. The ideal formulation of the kits as well as the use of liquid nitrogen in the freezing process, determined the lyophilization success. Distribution biological studies of the {sup 99m}Tc complexes were performed on mice by invasive method and on bigger animals by scintigraphic evaluation. Biological distribution studies of the complex {sup 99m}Tc-L,L-EC showed fast blood clearance, with the elimination of about 90% of the administered dose after 60 minutes, almost exclusively by the urinary system. The biological distribution results were adjusted to a three compartmental distribution model, as expected for a radiopharmaceutical designed to renal dynamic studies, with tubular elimination. The complex interaction with renal tubular receptors is related with structural characteristics of the compound, more specifically with the presence and location of polar groups. In comparison with {sup 99m}Tc-L,L-EC, biological studies of the complex {sup 99m}Tc -L,L-ECD showed different distribution aspects, despite some structural similarities. The presence of ethyl groups confers to the complex neutrality and lipophilicity. It cross the intact blood brain barrier and is retained in the brain

  19. DipM, a new factor required for peptidoglycan remodelling during cell division in Caulobacter crescentus.

    Science.gov (United States)

    Möll, Andrea; Schlimpert, Susan; Briegel, Ariane; Jensen, Grant J; Thanbichler, Martin

    2010-07-01

    In bacteria, cytokinesis is dependent on lytic enzymes that facilitate remodelling of the cell wall during constriction. In this work, we identify a thus far uncharacterized periplasmic protein, DipM, that is required for cell division and polarity in Caulobacter crescentus. DipM is composed of four peptidoglycan binding (LysM) domains and a C-terminal lysostaphin-like (LytM) peptidase domain. It binds to isolated murein sacculi in vitro, and is recruited to the site of constriction through interaction with the cell division protein FtsN. Mutational analyses showed that the LysM domains are necessary and sufficient for localization of DipM, while its peptidase domain is essential for function. Consistent with a role in cell wall hydrolysis, DipM was found to interact with purified murein sacculi in vitro and to induce cell lysis upon overproduction. Its inactivation causes severe defects in outer membrane invagination, resulting in a significant delay between cytoplasmic compartmentalization and final separation of the daughter cells. Overall, these findings indicate that DipM is a periplasmic component of the C. crescentus divisome that facilitates remodelling of the peptidoglycan layer and, thus, coordinated constriction of the cell envelope during the division process.

  20. Polar Location of the Chemoreceptor Complex in the Escherichia coli Cell

    Science.gov (United States)

    Maddock, Janine R.; Shapiro, Lucille

    1993-03-01

    The eukaryotic cell exhibits compartmentalization of functions to various membrane-bound organelles and to specific domains within each membrane. The spatial distribution of the membrane chemoreceptors and associated cytoplasmic chemotaxis proteins in Escherichia coli were examined as a prototypic functional aggregate in bacterial cells. Bacterial chemotaxis involves a phospho-relay system brought about by ligand association with a membrane receptor, culminating in a switch in the direction of flagellar rotation. The transduction of the chemotaxis signal is initiated by a chemoreceptor-CheW-CheA ternary complex at the inner membrane. These ternary complexes aggregate predominantly at the cell poles. Polar localization of the cytoplasmic CheA and CheW proteins is dependent on membrane-bound chemoreceptor. Chemoreceptors are not confined to the cell poles in strains lacking both CheA and CheW. The chemoreceptor-CheW binary complex is polarly localized in the absence of CheA, whereas the chemoreceptor-CheA binary complex is not confined to the cell poles in strains lacking CheW. The subcellular localization of the chemotaxis proteins may reflect a general mechanism by which the bacterial cell sequesters different regions of the cell for specialized functions.

  1. Intrinsic bursting of AII amacrine cells underlies oscillations in the rd1 mouse retina.

    Science.gov (United States)

    Choi, Hannah; Zhang, Lei; Cembrowski, Mark S; Sabottke, Carl F; Markowitz, Alexander L; Butts, Daniel A; Kath, William L; Singer, Joshua H; Riecke, Hermann

    2014-09-15

    In many forms of retinal degeneration, photoreceptors die but inner retinal circuits remain intact. In the rd1 mouse, an established model for blinding retinal diseases, spontaneous activity in the coupled network of AII amacrine and ON cone bipolar cells leads to rhythmic bursting of ganglion cells. Since such activity could impair retinal and/or cortical responses to restored photoreceptor function, understanding its nature is important for developing treatments of retinal pathologies. Here we analyzed a compartmental model of the wild-type mouse AII amacrine cell to predict that the cell's intrinsic membrane properties, specifically, interacting fast Na and slow, M-type K conductances, would allow its membrane potential to oscillate when light-evoked excitatory synaptic inputs were withdrawn following photoreceptor degeneration. We tested and confirmed this hypothesis experimentally by recording from AIIs in a slice preparation of rd1 retina. Additionally, recordings from ganglion cells in a whole mount preparation of rd1 retina demonstrated that activity in AIIs was propagated unchanged to elicit bursts of action potentials in ganglion cells. We conclude that oscillations are not an emergent property of a degenerated retinal network. Rather, they arise largely from the intrinsic properties of a single retinal interneuron, the AII amacrine cell. PMID:25008417

  2. Superoxide radical and iron modulate aconitase activity in mammalian cells.

    Science.gov (United States)

    Gardner, P R; Raineri, I; Epstein, L B; White, C W

    1995-06-01

    Aconitase is a member of a family of iron-sulfur-containing (de)hydratases whose activities are modulated in bacteria by superoxide radical (O2-.)-mediated inactivation and iron-dependent reactivation. The inactivation-reactivation of aconitase(s) in cultured mammalian cells was explored since these reactions may impact important and diverse aconitase functions in the cytoplasm and mitochondria. Conditions which increase O2-. production including exposure to the redox-cycling agent phenazine methosulfate (PMS), inhibitors of mitochondrial ubiquinol-cytochrome c oxidoreductase, or hyperoxia inactivated aconitase in mammalian cells. Overproduction of mitochondrial Mn-superoxide dismutase protected aconitase from inactivation by PMS or inhibitors of ubiquinol-cytochrome c oxidoreductase, but not from normobaric hyperoxia. Aconitase activity was reactivated (t1/2 of 12 +/- 3 min) upon removal of PMS. The iron chelator deferoxamine impaired reactivation and increased net inactivation of aconitase by O2-.. The ability of ubiquinol-cytochrome c oxidoreductase-generated O2-. to inactivate aconitase in several cell types correlated with the fraction of the aconitase activity localized in mitochondria. Extracellular O2-. generated with xanthine oxidase did not affect aconitase activity nor did exogenous superoxide dismutase decrease aconitase inactivation by PMS. The results demonstrate a dynamic and cyclical O2-.-mediated inactivation and iron-dependent reactivation of the mammalian [4Fe-4S] aconitases under normal and stress conditions and provide further evidence for the membrane compartmentalization of O2-.. PMID:7768942

  3. Lipid raft involvement in yeast cell growth and death.

    Science.gov (United States)

    Mollinedo, Faustino

    2012-01-01

    The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Cryptococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na(+), K(+), and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  4. Lipid raft involvement in yeast cell growth and death

    Directory of Open Access Journals (Sweden)

    Faustino eMollinedo

    2012-10-01

    Full Text Available The notion that cellular membranes contain distinct microdomains, acting as scaffolds for signal transduction processes, has gained considerable momentum. In particular, a class of such domains that is rich in sphingolipids and cholesterol, termed as lipid rafts, is thought to compartmentalize the plasma membrane, and to have important roles in survival and cell death signaling in mammalian cells. Likewise, yeast lipid rafts are membrane domains enriched in sphingolipids and ergosterol, the yeast counterpart of mammalian cholesterol. Sterol-rich membrane domains have been identified in several fungal species, including the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe as well as the pathogens Candida albicans and Crytococcus neoformans. Yeast rafts have been mainly involved in membrane trafficking, but increasing evidence implicates rafts in a wide range of additional cellular processes. Yeast lipid rafts house biologically important proteins involved in the proper function of yeast, such as proteins that control Na+, K+ and pH homeostasis, which influence many cellular processes, including cell growth and death. Membrane raft constituents affect drug susceptibility, and drugs interacting with sterols alter raft composition and membrane integrity, leading to yeast cell death. Because of the genetic tractability of yeast, analysis of yeast rafts could be an excellent model to approach unanswered questions of mammalian raft biology, and to understand the role of lipid rafts in the regulation of cell death and survival in human cells. A better insight in raft biology might lead to envisage new raft-mediated approaches to the treatment of human diseases where regulation of cell death and survival is critical, such as cancer and neurodegenerative diseases.

  5. Functional amyloid formation in LPS activated cells from invertebrates to vertebrates

    Directory of Open Access Journals (Sweden)

    A Grimaldi

    2014-10-01

    Full Text Available LPS stimulation provokes serious cellular stress with an increase of cytoplasmic reactive oxygen species (ROS. We have investigated, among the different cellular defenses, amyloidogenesis as common physiological response to attenuate oxidative stress. Optical and electron microscopic observations of the following LPS activated cell lines [insect (larval hemocytes, IPLB-LdFB and Drosophila Schneider’s S2 cells; mouse (NIH3T3 embryonic fibroblasts; Human (Human Umbilical Vein Endothelial Cells (HUVEC, neutrophils, and mesenchymal stem cells] reveal that, all are characterized by irregular profiles, cytoplasmic empty vacuoles or by cisternae containing fibrillar material. The compartmentalized fibrillar material shows staining properties typical of amyloid fibrils. LPS activation leads to ROS generation, resulting in pH acidification. Stimulated cells show pink cytoplasm in May-Grünwald Giemsa differential staining, giving a gross indication of a lower intracellular pH. Moreover the activation of amyloidogenesis is also linked with an extensive production of ACTH and α-MSH in all cultured cell types. We suggest that amyloidogenesis is a common, physiological cellular response to weak ROS, starting when other anti-stress cellular systems failed to restore homeostasis. The morphological evidence and/or functional characterization of synthesized amyloid fibrils could be an early indicator of oxidative stress that may lead to a general inflammatory process.

  6. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  7. Splenectomy alters distribution and turnover but not numbers or protective capacity of de novo generated memory CD8 T cells.

    Directory of Open Access Journals (Sweden)

    Marie eKim

    2014-11-01

    Full Text Available The spleen is a highly compartmentalized lymphoid organ that allows for efficient antigen presentation and activation of immune responses. Additionally, the spleen itself functions to remove senescent red blood cells, filter bacteria, and sequester platelets. Splenectomy, commonly performed after blunt force trauma or splenomegaly, has been shown to increase risk of certain bacterial and parasitic infections years after removal of the spleen. Although previous studies report defects in memory B cells and IgM titers in splenectomized patients, the effect of splenectomy on CD8 T cell responses and memory CD8 T cell function remains ill defined. Using TCR-transgenic P14 cells, we demonstrate that homeostatic proliferation and representation of pathogen-specific memory CD8 T cells in the blood are enhanced in splenectomized compared to sham surgery mice. Surprisingly, despite the enhanced turnover, splenectomized mice displayed no changes in total memory CD8 T cell numbers nor impaired protection against lethal dose challenge with Listeria monocytogenes. Thus, our data suggest that memory CD8 T cell maintenance and function remain intact in the absence of the spleen.

  8. Gene expression programs of mouse endothelial cells in kidney development and disease.

    Science.gov (United States)

    Brunskill, Eric W; Potter, S Steven

    2010-01-01

    Endothelial cells are remarkably heterogeneous in both morphology and function, and they play critical roles in the formation of multiple organ systems. In addition endothelial cell dysfunction can contribute to disease processes, including diabetic nephropathy, which is a leading cause of end stage renal disease. In this report we define the comprehensive gene expression programs of multiple types of kidney endothelial cells, and analyze the differences that distinguish them. Endothelial cells were purified from Tie2-GFP mice by cell dissociation and fluorescent activated cell sorting. Microarrays were then used to provide a global, quantitative and sensitive measure of gene expression levels. We examined renal endothelial cells from the embryo and from the adult glomerulus, cortex and medulla compartments, as well as the glomerular endothelial cells of the db/db mutant mouse, which represents a model for human diabetic nephropathy. The results identified the growth factors, receptors and transcription factors expressed by these multiple endothelial cell types. Biological processes and molecular pathways were characterized in exquisite detail. Cell type specific gene expression patterns were defined, finding novel molecular markers and providing a better understanding of compartmental distinctions. Further, analysis of enriched, evolutionarily conserved transcription factor binding sites in the promoters of co-activated genes begins to define the genetic regulatory network of renal endothelial cell formation. Finally, the gene expression differences associated with diabetic nephropathy were defined, providing a global view of both the pathogenic and protective pathways activated. These studies provide a rich resource to facilitate further investigations of endothelial cell functions in kidney development, adult compartments, and disease. PMID:20706631

  9. Gene expression programs of mouse endothelial cells in kidney development and disease.

    Directory of Open Access Journals (Sweden)

    Eric W Brunskill

    Full Text Available Endothelial cells are remarkably heterogeneous in both morphology and function, and they play critical roles in the formation of multiple organ systems. In addition endothelial cell dysfunction can contribute to disease processes, including diabetic nephropathy, which is a leading cause of end stage renal disease. In this report we define the comprehensive gene expression programs of multiple types of kidney endothelial cells, and analyze the differences that distinguish them. Endothelial cells were purified from Tie2-GFP mice by cell dissociation and fluorescent activated cell sorting. Microarrays were then used to provide a global, quantitative and sensitive measure of gene expression levels. We examined renal endothelial cells from the embryo and from the adult glomerulus, cortex and medulla compartments, as well as the glomerular endothelial cells of the db/db mutant mouse, which represents a model for human diabetic nephropathy. The results identified the growth factors, receptors and transcription factors expressed by these multiple endothelial cell types. Biological processes and molecular pathways were characterized in exquisite detail. Cell type specific gene expression patterns were defined, finding novel molecular markers and providing a better understanding of compartmental distinctions. Further, analysis of enriched, evolutionarily conserved transcription factor binding sites in the promoters of co-activated genes begins to define the genetic regulatory network of renal endothelial cell formation. Finally, the gene expression differences associated with diabetic nephropathy were defined, providing a global view of both the pathogenic and protective pathways activated. These studies provide a rich resource to facilitate further investigations of endothelial cell functions in kidney development, adult compartments, and disease.

  10. B cells and antibodies in progressive multiple sclerosis: Contribution to neurodegeneration and progression.

    Science.gov (United States)

    Fraussen, Judith; de Bock, Laura; Somers, Veerle

    2016-09-01

    Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by demyelination, axonal degeneration and gliosis. The progressive form of MS is an important research topic as not much is known about its underlying mechanisms and no therapy is available. Although progressive MS is traditionally considered to be driven by neurodegeneration, compartmentalized CNS inflammation is currently accepted as one of the driving processes behind neurodegeneration and progression. In this review, the involvement of B cells and antibodies in progressive MS is discussed. The identification of meningeal ectopic B cell follicles in secondary progressive MS (SPMS) patients and the successful use of B cell-depleting therapy in primary progressive MS (PPMS) patients have underlined the importance of B cells in progressive MS. Proof is also available for the role of antibodies in neurodegeneration and progression in MS. Here, oligoclonal immunoglobulin M (IgM) production and autoreactive antibodies are described, with a focus on antibodies directed against sperm-associated antigen 16 (SPAG16). Further research into the role of B cells and autoantibodies in MS progression can lead to novel prognostic and theranostic opportunities.

  11. TLR4 signalling in pulmonary stromal cells is critical for inflammation and immunity in the airways.

    Science.gov (United States)

    Perros, Frederic; Lambrecht, Bart N; Hammad, Hamida

    2011-01-01

    Inflammation of the airways, which is often associated with life-threatening infection by Gram-negative bacteria or presence of endotoxin in the bioaerosol, is still a major cause of severe airway diseases. Moreover, inhaled endotoxin may play an important role in the development and progression of airway inflammation in asthma. Pathologic changes induced by endotoxin inhalation include bronchospasm, airflow obstruction, recruitment of inflammatory cells, injury of the alveolar epithelium, and disruption of pulmonary capillary integrity leading to protein rich fluid leak in the alveolar space. Mammalian Toll-like receptors (TLRs) are important signalling receptors in innate host defense. Among these receptors, TLR4 plays a critical role in the response to endotoxin. Lungs are a complex compartmentalized organ with separate barriers, namely the alveolar-capillary barrier, the microvascular endothelium, and the alveolar epithelium. An emerging theme in the field of lung immunology is that structural cells (SCs) of the airways such as epithelial cells (ECs), endothelial cells, fibroblasts and other stromal cells produce activating cytokines that determine the quantity and quality of the lung immune response. This review focuses on the role of TLR4 in the innate and adaptive immune functions of the pulmonary SCs. PMID:21943186

  12. Induction of indoleamine 2,3-dioxygenase in vascular smooth muscle cells by interferon-gamma contributes to medial immunoprivilege.

    Science.gov (United States)

    Cuffy, Madison C; Silverio, Amanda M; Qin, Lingfeng; Wang, Yinong; Eid, Raymond; Brandacher, Gerald; Lakkis, Fadi G; Fuchs, Dietmar; Pober, Jordan S; Tellides, George

    2007-10-15

    Atherosclerosis and graft arteriosclerosis are characterized by leukocytic infiltration of the vessel wall that spares the media. The mechanism(s) for medial immunoprivilege is unknown. In a chimeric humanized mouse model of allograft rejection, medial immunoprivilege was associated with expression of IDO by vascular smooth muscle cells (VSMCs) of rejecting human coronary artery grafts. Inhibition of IDO by 1-methyl-tryptophan (1-MT) increased medial infiltration by allogeneic T cells and increased VSMC loss. IFN-gamma-induced IDO expression and activity in cultured human VSMCs was considerably greater than in endothelial cells (ECs) or T cells. IFN-gamma-treated VSMCs, but not untreated VSMCs nor ECs with or without IFN-gamma pretreatment, inhibited memory Th cell alloresponses across a semipermeable membrane in vitro. This effect was reversed by 1-MT treatment or tryptophan supplementation and replicated by the absence of tryptophan, but not by addition of tryptophan metabolites. However, IFN-gamma-treated VSMCs did not activate allogeneic memory Th cells, even after addition of 1-MT or tryptophan. Our work extends the concept of medial immunoprivilege to include immune regulation, establishes the compartmentalization of immune responses within the vessel wall due to distinct microenvironments, and demonstrates a duality of stimulatory EC signals versus inhibitory VSMC signals to artery-infiltrating T cells that may contribute to the chronicity of arteriosclerotic diseases.

  13. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    International Nuclear Information System (INIS)

    It has been suggested that cholesterol may modulate amyloid-β (Aβ) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD (β-amyloid precursor protein (APP), β-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/Aβ formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1-/- cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, γ-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards Aβ occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  14. Quantitative chemical imaging of the intracellular spatial distribution of fundamental elements and light metals in single cells.

    Science.gov (United States)

    Malucelli, Emil; Iotti, Stefano; Gianoncelli, Alessandra; Fratini, Michela; Merolle, Lucia; Notargiacomo, Andrea; Marraccini, Chiara; Sargenti, Azzurra; Cappadone, Concettina; Farruggia, Giovanna; Bukreeva, Inna; Lombardo, Marco; Trombini, Claudio; Maier, Jeanette A; Lagomarsino, Stefano

    2014-05-20

    We report a method that allows a complete quantitative characterization of whole single cells, assessing the total amount of carbon, nitrogen, oxygen, sodium, and magnesium and providing submicrometer maps of element molar concentration, cell density, mass, and volume. This approach allows quantifying elements down to 10(6) atoms/μm(3). This result was obtained by applying a multimodal fusion approach that combines synchrotron radiation microscopy techniques with off-line atomic force microscopy. The method proposed permits us to find the element concentration in addition to the mass fraction and provides a deeper and more complete knowledge of cell composition. We performed measurements on LoVo human colon cancer cells sensitive (LoVo-S) and resistant (LoVo-R) to doxorubicin. The comparison of LoVo-S and LoVo-R revealed different patterns in the maps of Mg concentration with higher values within the nucleus in LoVo-R and in the perinuclear region in LoVo-S cells. This feature was not so evident for the other elements, suggesting that Mg compartmentalization could be a significant trait of the drug-resistant cells.

  15. Characteristics of cadmium tolerance in 'Hermes' flax seedlings: contribution of cell walls.

    Science.gov (United States)

    Douchiche, Olfa; Soret-Morvan, Odile; Chaïbi, Wided; Morvan, Claudine; Paynel, Florence

    2010-12-01

    Most flax (Linum usitatissimum) varieties are described as tolerant to high concentrations of Cd. The aim of the present paper was to better characterize this tolerance, by studying the responses of flax plantlets, cv Hermes, to 18d growth on 0.5mM Cd. In Cd-treated seedlings, the majority of Cd was compartmentalized in the roots. Analysis of other elements showed that only Fe concentration was reduced, while Mn increased. Growth parameters of Cd treated flax were only moderately altered, with similar mass tolerance-indices for roots and shoots. Tissue anatomy was unaffected by treatment. The effect on lipid peroxidation, protein carbonylation and antioxidative activities appeared low but slightly higher in roots. The most important impacts of Cd were, in all organs, cell expansion, cell-wall thickening, pectin cross-linking and increase of cell-wall enzymatic activities (pectin methylesterase and peroxidase). Thus, the role of the cell wall in Cd tolerance might be important at two levels: (i) in the reinforcement of the tissue cohesion and (ii) in the sequestration of Cd. PMID:20884040

  16. Glycosylation-mediated phenylpropanoid partitioning in Populus tremuloides cell cultures

    Directory of Open Access Journals (Sweden)

    Babst Benjamin A

    2009-12-01

    identified candidate genes for glycosyltransferases that may mediate the glycosylation, and for transporters that mediate the subcellular compartmentalization of sugars and phenolic glycosides. The suspension cells appear to represent a facile system for dissecting the regulation of phenolic carbon partitioning, and in turn, its effects on growth in Populus.

  17. Arsenite-activated JNK signaling enhances CPEB4-Vinexin interaction to facilitate stress granule assembly and cell survival.

    Directory of Open Access Journals (Sweden)

    Yu-Wei Chang

    Full Text Available Stress granules (SGs are compartmentalized messenger ribonucleoprotein particles (mRNPs where translationally repressed mRNAs are stored when cells encounter environmental stress. Cytoplasmic polyadenylation element-binding protein (CPEB4 is a sequence-specific RNA-binding protein and translational regulator. In keeping with the results obtained from the study of other RNA-binding proteins, we found CPEB4 localized in SGs in various arsenite-treated cells. In this study, we identified that Vinexin, a CPEB4-interacting protein, is a novel component of SGs. Vinexin is a SH3-domain-containing adaptor protein and affects cell migration through its association with Vinculin to localize at focal adhesions (FAs. Unexpectedly, Vinexin is translocated from FAs to SGs under arsenite-induced stress. The recruitment of Vinexin to SGs depends on its interaction with CPEB4 and influences SG formation and cell survival. Arsenite-activated c-Jun N-terminal kinase (JNK signaling enhances the association between CPEB4 and Vinexin, which consequently facilitates SG localization of Vinexin. Taken together, this study uncovers a novel interaction between a translational regulator and an adaptor protein to influence SG assembly and cell survival.

  18. A molecular network for the transport of the TI-VAMP/VAMP7 vesicles from cell center to periphery.

    Science.gov (United States)

    Burgo, Andrea; Proux-Gillardeaux, Véronique; Sotirakis, Emmanuel; Bun, Philippe; Casano, Alessandra; Verraes, Agathe; Liem, Ronald K H; Formstecher, Etienne; Coppey-Moisan, Maïté; Galli, Thierry

    2012-07-17

    The compartmental organization of eukaryotic cells is maintained dynamically by vesicular trafficking. SNARE proteins play a crucial role in intracellular membrane fusion and need to be targeted to their proper donor or acceptor membrane. The molecular mechanisms that allow for the secretory vesicles carrying the v-SNARE TI-VAMP/VAMP7 to leave the cell center, load onto microtubules, and reach the periphery to mediate exocytosis are largely unknown. Here, we show that the TI-VAMP/VAMP7 partner Varp, a Rab21 guanine nucleotide exchange factor, interacts with GolginA4 and the kinesin 1 Kif5A. Activated Rab21-GTP in turn binds to MACF1, an actin and microtubule regulator, which is itself a partner of GolginA4. These components are required for directed movement of TI-VAMP/VAMP7 vesicles from the cell center to the cell periphery. The molecular mechanisms uncovered here suggest an integrated view of the transport of vesicles carrying a specific v-SNARE toward the cell surface.

  19. A mechanistic compartmental model for total antibody uptake in tumors.

    Science.gov (United States)

    Thurber, Greg M; Dane Wittrup, K

    2012-12-01

    Antibodies are under development to treat a variety of cancers, such as lymphomas, colon, and breast cancer. A major limitation to greater efficacy for this class of drugs is poor distribution in vivo. Localization of antibodies occurs slowly, often in insufficient therapeutic amounts, and distributes heterogeneously throughout the tumor. While the microdistribution around individual vessels is important for many therapies, the total amount of antibody localized in the tumor is paramount for many applications such as imaging, determining the therapeutic index with antibody drug conjugates, and dosing in radioimmunotherapy. With imaging and pretargeted therapeutic strategies, the time course of uptake is critical in determining when to take an image or deliver a secondary reagent. We present here a simple mechanistic model of antibody uptake and retention that captures the major rates that determine the time course of antibody concentration within a tumor including dose, affinity, plasma clearance, target expression, internalization, permeability, and vascularization. Since many of the parameters are known or can be estimated in vitro, this model can approximate the time course of antibody concentration in tumors to aid in experimental design, data interpretation, and strategies to improve localization. PMID:22974563

  20. Compartmental Modelling of the Pharmacokinetics of an Efflux Transporter

    OpenAIRE

    Beyer, A.; Steinbach, A; Brožič, P.; Gobec, S.; Rižner, T. Lanišnik; Ablinger, E.; Wegscheider, S.; Pavkov-Keller, T.; Keller, W.; Milak, S.; Chemelli, A.; Glatter, O; Petró, É.; Csóka, I.; Balogh, Á

    2010-01-01

    The enhancement of dissolution rate is one of the most commonly used approaches to improve the bioavailability of drugs, since for a great extent of new drug substances their absorption is limited with their dissolution rate. The aim of this work was to prepare and optimize microparticles containing ketoprofen using spray-drying technology, which would enhance the dissolution rate of ketoprofen, which is poorly soluble at lower pH values. Different hydrophilic polymers with relatively low mel...

  1. Compartmentation and complexation of metals in hyperaccumulator plants

    OpenAIRE

    Leitenmaier, Barbara; Küpper, Hendrik

    2013-01-01

    Hyperaccumulators are being intensely investigated. They are not only interesting in scientific context due to their “strange” behavior in terms of dealing with high concentrations of metals, but also because of their use in phytoremediation and phytomining, for which understanding the mechanisms of hyperaccumulation is crucial. Hyperaccumulators naturally use metal accumulation as a defense against herbivores and pathogens, and therefore deal with accumulated metals in very specific ways of ...

  2. Compartmentation and complexation of metals in hyperaccumulator plants

    OpenAIRE

    Barbara eLeitenmaier; Hendrik eKüpper

    2013-01-01

    Hyperaccumulators are being intensely investigated. They are not only interesting in scientific context due to their strange behaviour in terms of dealing with high concentrations of metals, but also because of their use in phytoremediation and phytomining, for which understanding the mechanisms of hyperaccumulation is crucial. Hyperaccumulators naturally use metal accumulation as a defence against herbivores and pathogens, and therefore deal with accumulated metals in very specific ways of c...

  3. Differential compartmentalization and distinct functions of GABAB receptor variants

    DEFF Research Database (Denmark)

    Vigot, Réjan; Barbieri, Samuel; Bräuner-Osborne, Hans;

    2006-01-01

    GABAB receptors are the G protein-coupled receptors for the main inhibitory neurotransmitter in the brain, gamma-aminobutyric acid (GABA). Molecular diversity in the GABAB system arises from the GABAB1a and GABAB1b subunit isoforms that solely differ in their ectodomains by a pair of sushi repeats...... release, while predominantly GABAB1b mediates postsynaptic inhibition. Electron microscopy reveals a synaptic distribution of GABAB1 isoforms that agrees with the observed functional differences. Transfected CA3 neurons selectively express GABAB1a in distal axons, suggesting that the sushi repeats, a...

  4. Compartmentation of redox metabolites in the anterior eye segment?

    Science.gov (United States)

    Reim, M; Luthe, P

    1977-10-28

    In bovine corneal epithelium, stroma, and aqueous humor the levels of ascorbic acid (ASC) and dehydroascorbic acid (DHA) were investigated. Two methods were used, the photometric assay with 2,6-dichlorophenolindophenol and the formation of osazone by 2,4-dinitrophenylhydrazine. The ASC levels in the corneal epithelium and aqueous humor were found to be in the millimolar range, the ASC/DHA ratio being about 10. The stromal ASC and DHA levels were much lower, with a ratio of 0.7. ASC and DHA had similar levels and ratios to those of reduced and oxidized glutathione (GSH/GSSG) reported in the literature. In the corneal epithelium the redox ratio of glutathione was higher than that of ascorbic acid. Therefore, glutathione was supposed to reduce dehydroascorbic acid. PMID:303870

  5. Apartment Compartmentalization With an Aerosol-Based Sealing Process

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sean [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Berger, David [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Harrington, Curtis [Univ. of California, Davis, CA (United States)

    2015-03-01

    The U.S. Department of Energy Building America Team, Consortium for Advanced Residential Buildings, sought to demonstrate this new technology application in a new construction multifamily building in Queens, New York. The effectiveness of the sealing process was evaluated by three methods: air leakage testing of overall apartment before-and-after sealing, point-source testing of individual leaks, and pressure measurements in the walls of an apartment during sealing.

  6. Subcellular localization and compartmentation of thiamine derivatives in rat brain.

    Science.gov (United States)

    Bettendorff, L; Wins, P; Lesourd, M

    1994-05-26

    The subcellular distribution of thiamine derivatives in rat brain was studied. Thiamine diphosphate content was highest in the mitochondrial and synaptosomal fractions, and lowest in microsomal, myelin and cytosolic fractions. Only 3-5% of total thiamine diphosphate was bound to transketolase, a cytosolic enzyme. Thiamine triphosphate was barely detectable in the microsomal and cytosolic fraction, but synaptosomes were slightly enriched in this compound compared to the crude homogenate. Both myelin and mitochondrial fractions contained significant amounts of thiamine triphosphate. In order to estimate the relative turnover rates of these compounds, the animals received an intraperitoneal injection of either [14C]thiamine or [14C]sulbutiamine (isobutyrylthiamine disulfide) 1 h before decapitation. The specific radioactivities of thiamine compounds found in the brain decreased in the order: thiamine > thiamine triphosphate > thiamine monophosphate > thiamine diphosphate. Incorporation of radioactivity into thiamine triphosphate was more marked with [14C]sulbutiamine than with [14C]thiamine. The highest specific radioactivity of thiamine diphosphate was found in the cytosolic fraction of the brain, though this pool represents less than 10% of total thiamine diphosphate. Cytosolic thiamine diphosphate had a twice higher specific radioactivity when [14C]sulbutiamine was used as precursor compared with thiamine though no significant differences were found in the other cellular compartments. Our results suggest the existence of two thiamine diphosphate pools: the bound cofactor pool is essentially mitochondrial and has a low turnover; a much smaller cytosolic pool (6-7% of total TDP) of high turnover is the likely precursor of thiamine triphosphate. PMID:8186256

  7. In vivo metabolite compartmentalization probed using intracellular GdDTPA

    DEFF Research Database (Denmark)

    Peters, David Alberg; Rowland, Ian

    Fast trans-membrane water exchange enables in- tracellular relaxation enhancement of water by contrast agents in the extracellular space. For me- tabolites not in fast exchange across membranes, intracellular metabolite relaxation enhancement will only occur if the contrast agent and metabolite a...... are in the same compartment. Extracellular contrast has utilized electroporation methods to deliver GdDTPA into the cytosol of rat muscle in vivo in order to probe the intracellular compart- mentalization of MR-visible metabolites....

  8. Invasive cancer cells and metastasis

    Science.gov (United States)

    Mierke, Claudia Tanja

    2013-12-01

    the biophysical state of the primary tumor cell. To determine the cytoskeletal dynamics they chose magnetic twisting cytometry, where the spontaneous motion of surface bound marker beads was measured, which is a measure for the cytoskeletal remodeling dynamics. The group of Katarina Wolf measured the stiffness of the cell nucleus because it is the largest and stiffest organelle, which may hinder the migration of invasive tumor cells through dense connective tissue [2]. They combined atomic force confocal microscopy for measurement of bulk nuclear stiffness (the inverse of the compressibility) with simultaneous visualization of the cantilever-nucleus contact as well as monitoring of the cell's fate. The dynamics of tissue topology such as the mixing of compartments during cancer invasion and metastasis were theoretically analyzed by Lance L Munn [3]. In particular, he presented a mathematical model of tissue repair and tumor growth based on collective cell migration that simulates a wide range of tumor behaviors using correct tissue compartmentalization and connectivity. In the future, the topological analysis could be helpful for tumor diagnosis or monitoring tumor therapy. The group of Cynthia A Reinhart-King analyzed how the topological guidance of a 3D tumor cell migration at an interface of collagen densities affects cell motility [4]. In particular, they mimicked the heterogeneities in density of the tumor stroma by preparing gels with an interface of high and low density collagen gels and investigated how this affects cell motility. The author's review paper details the effect of focal adhesion proteins such as focal adhesion kinase (FAK) on cell motility and how this effect is driven by mechanical alterations of cells expressing FAK compared to cells with FAK knock-out [5]. In particular, it focused on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. This article highlights that both focal adhesion proteins

  9. Glyoxylate Reductase Isoform 1 is Localized in the Cytosol and Not Peroxisomes in Plant Cells

    Institute of Scientific and Technical Information of China (English)

    Steven L. K. Ching; Satinder K. Gidda; Amanda Rochon; Owen R. van Cauwenberghe; Barry J. Shelp; Robert T. Mullen

    2012-01-01

    Glyoxylate reductase (GLYR) is a key enzyme in plant metabolism which catalyzes the detoxification of both photorespiratory glyoxylate and succinic semialdehdye,an intermediate of the γ-aminobutyrate (GABA) pathway.Two isoforms of GLYR exist in plants,GLYR1 and GLYR2,and while GLYR2 is known to be localized in plastids,GLYR1 has been reported to be localized in either peroxisomes or the cytosol.Here,we reappraised the intracellular localization of GLYR1 in Arabidopsis thaliana L.Heynh (ecotype Lansberg erecta) using both transiently-transformed suspension cells and stably-transformed plants,in combination with fluorescence microscopy.The results indicate that GLYR1 is localized exclusively to the cytosol regardless of the species,tissue and/or cell type,or exposure of plants to environmental stresses that would increase flux through the GABA pathway.Moreover,the C-terminal tripeptide sequence of GLYR1,-SRE,despite its resemblance to a type 1 peroxisomal targeting signal,is not sufficient for targeting to peroxisomes.Collectively,these results define the cytosol as the intracellular location of GLYR1 and provide not only important insight to the metabolic roles of GLYR1 and the compartmentation of the GABA and photorespiratory pathways in plant cells,but also serve as a useful reference for future studies of proteins proposed to be localized to peroxisomes and/or the cytosol.

  10. Local ATP generation by brain-type creatine kinase (CK-B facilitates cell motility.

    Directory of Open Access Journals (Sweden)

    Jan W P Kuiper

    Full Text Available BACKGROUND: Creatine Kinases (CK catalyze the reversible transfer of high-energy phosphate groups between ATP and phosphocreatine, thereby playing a storage and distribution role in cellular energetics. Brain-type CK (CK-B deficiency is coupled to loss of function in neural cell circuits, altered bone-remodeling by osteoclasts and complement-mediated phagocytotic activity of macrophages, processes sharing dependency on actomyosin dynamics. METHODOLOGY/PRINCIPAL FINDINGS: Here, we provide evidence for direct coupling between CK-B and actomyosin activities in cortical microdomains of astrocytes and fibroblasts during spreading and migration. CK-B transiently accumulates in membrane ruffles and ablation of CK-B activity affects spreading and migration performance. Complementation experiments in CK-B-deficient fibroblasts, using new strategies to force protein relocalization from cytosol to cortical sites at membranes, confirmed the contribution of compartmentalized CK-B to cell morphogenetic dynamics. CONCLUSION/SIGNIFICANCE: Our results provide evidence that local cytoskeletal dynamics during cell motility is coupled to on-site availability of ATP generated by CK-B.

  11. The Spectrum and Regulatory Landscape of Intestinal Innate Lymphoid Cells Are Shaped by the Microbiome.

    Science.gov (United States)

    Gury-BenAri, Meital; Thaiss, Christoph A; Serafini, Nicolas; Winter, Deborah R; Giladi, Amir; Lara-Astiaso, David; Levy, Maayan; Salame, Tomer Meir; Weiner, Assaf; David, Eyal; Shapiro, Hagit; Dori-Bachash, Mally; Pevsner-Fischer, Meirav; Lorenzo-Vivas, Erika; Keren-Shaul, Hadas; Paul, Franziska; Harmelin, Alon; Eberl, Gérard; Itzkovitz, Shalev; Tanay, Amos; Di Santo, James P; Elinav, Eran; Amit, Ido

    2016-08-25

    Innate lymphoid cells (ILCs) are critical modulators of mucosal immunity, inflammation, and tissue homeostasis, but their full spectrum of cellular states and regulatory landscapes remains elusive. Here, we combine genome-wide RNA-seq, ChIP-seq, and ATAC-seq to compare the transcriptional and epigenetic identity of small intestinal ILCs, identifying thousands of distinct gene profiles and regulatory elements. Single-cell RNA-seq and flow and mass cytometry analyses reveal compartmentalization of cytokine expression and metabolic activity within the three classical ILC subtypes and highlight transcriptional states beyond the current canonical classification. In addition, using antibiotic intervention and germ-free mice, we characterize the effect of the microbiome on the ILC regulatory landscape and determine the response of ILCs to microbial colonization at the single-cell level. Together, our work characterizes the spectrum of transcriptional identities of small intestinal ILCs and describes how ILCs differentially integrate signals from the microbial microenvironment to generate phenotypic and functional plasticity.

  12. Dynamic FDG-PET Imaging to Differentiate Malignancies from Inflammation in Subcutaneous and In Situ Mouse Model for Non-Small Cell Lung Carcinoma (NSCLC.

    Directory of Open Access Journals (Sweden)

    Zhen Yang

    Full Text Available [18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET has been widely used in oncologic procedures such as tumor diagnosis and staging. However, false-positive rates have been high, unacceptable and mainly caused by inflammatory lesions. Misinterpretations take place especially when non-subcutaneous inflammations appear at the tumor site, for instance in the lung. The aim of the current study is to evaluate the use of dynamic PET imaging procedure to differentiate in situ and subcutaneous non-small cell lung carcinoma (NSCLC from inflammation, and estimate the kinetics of inflammations in various locations.Dynamic FDG-PET was performed on 33 female mice inoculated with tumor and/or inflammation subcutaneously or inside the lung. Standardized Uptake Values (SUVs from static imaging (SUVmax as well as values of influx rate constant (Ki of compartmental modeling from dynamic imaging were obtained. Static and kinetic data from different lesions (tumor and inflammations or different locations (subcutaneous, in situ and spontaneous group were compared.Values of SUVmax showed significant difference in subcutaneous tumor and inflammation (p<0.01, and in inflammations from different locations (p<0.005. However, SUVmax showed no statistical difference between in situ tumor and inflammation (p = 1.0 and among tumors from different locations (subcutaneous and in situ, p = 0.91. Values of Ki calculated from compartmental modeling showed significant difference between tumor and inflammation both subcutaneously (p<0.005 and orthotopically (p<0.01. Ki showed also location specific values for inflammations (subcutaneous, in situ and spontaneous, p<0.015. However, Ki of tumors from different locations (subcutaneous and in situ showed no significant difference (p = 0.46.In contrast to static PET based SUVmax, both subcutaneous and in situ inflammations and malignancies can be differentiated via dynamic FDG-PET based Ki. Moreover, Values of influx

  13. Distinct and conserved prominin-1/CD133-positive retinal cell populations identified across species.

    Directory of Open Access Journals (Sweden)

    József Jászai

    Full Text Available Besides being a marker of various somatic stem cells in mammals, prominin-1 (CD133 plays a role in maintaining the photoreceptor integrity since mutations in the PROM1 gene are linked with retinal degeneration. In spite of that, little information is available regarding its distribution in eyes of non-mammalian vertebrates endowed with high regenerative abilities. To address this subject, prominin-1 cognates were isolated from axolotl, zebrafish and chicken, and their retinal compartmentalization was investigated and compared to that of their mammalian orthologue. Interestingly, prominin-1 transcripts--except for the axolotl--were not strictly restricted to the outer nuclear layer (i.e., photoreceptor cells, but they also marked distinct subdivisions of the inner nuclear layer (INL. In zebrafish, where the prominin-1 gene is duplicated (i.e., prominin-1a and prominin-1b, a differential expression was noted for both paralogues within the INL being localized either to its vitreal or scleral subdivision, respectively. Interestingly, expression of prominin-1a within the former domain coincided with Pax-6-positive cells that are known to act as progenitors upon injury-induced retino-neurogenesis. A similar, but minute population of prominin-1-positive cells located at the vitreal side of the INL was also detected in developing and adult mice. In chicken, however, prominin-1-positive cells appeared to be aligned along the scleral side of the INL reminiscent of zebrafish prominin-1b. Taken together our data indicate that in addition to conserved expression of prominin-1 in photoreceptors, significant prominin-1-expressing non-photoreceptor retinal cell populations are present in the vertebrate eye that might represent potential sources of stem/progenitor cells for regenerative therapies.

  14. Direct transfer of viral and cellular proteins from varicella-zoster virus-infected non-neuronal cells to human axons.

    Directory of Open Access Journals (Sweden)

    Sergei Grigoryan

    Full Text Available Varicella Zoster Virus (VZV, the alphaherpesvirus that causes varicella upon primary infection and Herpes zoster (shingles following reactivation in latently infected neurons, is known to be fusogenic. It forms polynuclear syncytia in culture, in varicella skin lesions and in infected fetal human ganglia xenografted to mice. After axonal infection using VZV expressing green fluorescent protein (GFP in compartmentalized microfluidic cultures there is diffuse filling of axons with GFP as well as punctate fluorescence corresponding to capsids. Use of viruses with fluorescent fusions to VZV proteins reveals that both proteins encoded by VZV genes and those of the infecting cell are transferred in bulk from infecting non-neuronal cells to axons. Similar transfer of protein to axons was observed following cell associated HSV1 infection. Fluorescence recovery after photobleaching (FRAP experiments provide evidence that this transfer is by diffusion of proteins from the infecting cells into axons. Time-lapse movies and immunocytochemical experiments in co-cultures demonstrate that non-neuronal cells fuse with neuronal somata and proteins from both cell types are present in the syncytia formed. The fusogenic nature of VZV therefore may enable not only conventional entry of virions and capsids into axonal endings in the skin by classical entry mechanisms, but also by cytoplasmic fusion that permits viral protein transfer to neurons in bulk.

  15. Selenium Metabolism in Cancer Cells: The Combined Application of XAS and XFM Techniques to the Problem of Selenium Speciation in Biological Systems

    Directory of Open Access Journals (Sweden)

    Hugh H. Harris

    2013-05-01

    Full Text Available Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS and X-ray fluorescence microscopy (XFM. The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.

  16. Regulatory T cells with multiple suppressive and potentially pro-tumor activities accumulate in human colorectal cancer.

    Science.gov (United States)

    Timperi, Eleonora; Pacella, Ilenia; Schinzari, Valeria; Focaccetti, Chiara; Sacco, Luca; Farelli, Francesco; Caronna, Roberto; Del Bene, Gabriella; Longo, Flavia; Ciardi, Antonio; Morelli, Sergio; Vestri, Anna Rita; Chirletti, Piero; Barnaba, Vincenzo; Piconese, Silvia

    2016-07-01

    Tregs can contribute to tumor progression by suppressing antitumor immunity. Exceptionally, in human colorectal cancer (CRC), Tregs are thought to exert beneficial roles in controlling pro-tumor chronic inflammation. The goal of our study was to characterize CRC-infiltrating Tregs at multiple levels, by phenotypical, molecular and functional evaluation of Tregs from the tumor site, compared to non-tumoral mucosa and peripheral blood of CRC patients. The frequency of Tregs was higher in mucosa than in blood, and further significantly increased in tumor. Ex vivo, those Tregs suppressed the proliferation of tumor-infiltrating CD8(+) and CD4(+) T cells. A differential compartmentalization was detected between Helios(high) and Helios(low) Treg subsets (thymus-derived versus peripherally induced): while Helios(low) Tregs were enriched in both sites, only Helios(high) Tregs accumulated significantly and specifically in tumors, displayed a highly demethylated TSDR region and contained high proportions of cells expressing CD39 and OX40, markers of activation and suppression. Besides the suppression of T cells, Tregs may contribute to CRC progression also through releasing IL-17, or differentiating into Tfr cells that potentially antagonize a protective Tfh response, events that were both detected in tumor-associated Tregs. Overall, our data indicate that Treg accumulation may contribute through multiple mechanisms to CRC establishment and progression. PMID:27622025

  17. Pneumatic-aided micro-molding for flexible fabrication of homogeneous and heterogeneous cell-laden microgels.

    Science.gov (United States)

    Ma, Chao; Tian, Chang; Zhao, Lei; Wang, Jinyi

    2016-07-01

    Microgels are favorable for numerous applications such as drug delivery, biomaterials science and tissue engineering. Conventionally, photolithographic methods and micro-molding techniques are extensively exploited to prepare microgels; however, they are, respectively, limited to photocrosslinkable polymers and inadequate to generate serially patterned hydrogels due to the static nature of utilized molds. Herein, we proposed a simple and versatile approach, termed pneumatic-aided micro-molding (PAM), to flexibly fabricate microgels with precise control over multiple cell types and microarchitectures of hydrogels through strategically designed pneumatic microvalves. Using the PAM approach, different cells were encapsulated in various hydrogels that had well-defined geometries. Additionally, single/multiple micro-channeled cell-laden microgels were fabricated, of which the shape, number and arrangement could be finely tuned by varying microvalve configurations. Moreover, multi-compartmental microgels comprising composite hydrogel structures were engineered following a two-step PAM, which demonstrated the utility for biomimetically constructing a three-dimensional (3D) liver microtissue composed of a radially orchestrated network of hepatic cords and sinusoids. The resulting microtissue resembled the organizational complexity of the liver lobule and was applied for the evaluation of acetaminophen-induced hepatotoxicity. Collectively, the PAM strategy could be a useful and powerful tool in biomedical engineering, in vitro 3D cell culture, and fundamental biological studies.

  18. Pneumatic-aided micro-molding for flexible fabrication of homogeneous and heterogeneous cell-laden microgels.

    Science.gov (United States)

    Ma, Chao; Tian, Chang; Zhao, Lei; Wang, Jinyi

    2016-07-01

    Microgels are favorable for numerous applications such as drug delivery, biomaterials science and tissue engineering. Conventionally, photolithographic methods and micro-molding techniques are extensively exploited to prepare microgels; however, they are, respectively, limited to photocrosslinkable polymers and inadequate to generate serially patterned hydrogels due to the static nature of utilized molds. Herein, we proposed a simple and versatile approach, termed pneumatic-aided micro-molding (PAM), to flexibly fabricate microgels with precise control over multiple cell types and microarchitectures of hydrogels through strategically designed pneumatic microvalves. Using the PAM approach, different cells were encapsulated in various hydrogels that had well-defined geometries. Additionally, single/multiple micro-channeled cell-laden microgels were fabricated, of which the shape, number and arrangement could be finely tuned by varying microvalve configurations. Moreover, multi-compartmental microgels comprising composite hydrogel structures were engineered following a two-step PAM, which demonstrated the utility for biomimetically constructing a three-dimensional (3D) liver microtissue composed of a radially orchestrated network of hepatic cords and sinusoids. The resulting microtissue resembled the organizational complexity of the liver lobule and was applied for the evaluation of acetaminophen-induced hepatotoxicity. Collectively, the PAM strategy could be a useful and powerful tool in biomedical engineering, in vitro 3D cell culture, and fundamental biological studies. PMID:27229899

  19. T Cells

    Science.gov (United States)

    T Cells - National Multiple Sclerosis Society Skip to navigation Skip to content Menu Navigation National Multiple Sclerosis Society Sign ... Is MS? Definition of MS T Cells T Cells Share Smaller Text Larger Text Print In this ...

  20. Cell counting.

    Science.gov (United States)

    Phelan, M C; Lawler, G

    2001-05-01

    This unit presents protocols for counting cells using either a hemacytometer or electronically using a Coulter counter. Cell counting with a hemacytometer permits effective discrimination of live from dead cells using trypan blue exclusion. In addition, the procedure is less subject to errors arising from cell clumping or size heterogeneity. Counting cells is more quickly and easily performed using an electronic counter, but live-dead discrimination is unreliable. Cell populations containing large numbers of dead cells and/or cell clumps are difficult to count accurately. In addition, electronic counting requires resetting of the instrument for cell populations of different sizes; heterogeneous populations can give rise to inaccurate counts, and resting and activated cells may require counting at separate settings. In general, electronic cell counting is best performed on fresh peripheral blood cells. PMID:18770655

  1. The ADP-ribose polymerase Tankyrase regulates adult intestinal stem cell proliferation during homeostasis in Drosophila.

    Science.gov (United States)

    Wang, Zhenghan; Tian, Ai; Benchabane, Hassina; Tacchelly-Benites, Ofelia; Yang, Eungi; Nojima, Hisashi; Ahmed, Yashi

    2016-05-15

    Wnt/β-catenin signaling controls intestinal stem cell (ISC) proliferation, and is aberrantly activated in colorectal cancer. Inhibitors of the ADP-ribose polymerase Tankyrase (Tnks) have become lead therapeutic candidates for Wnt-driven cancers, following the recent discovery that Tnks targets Axin, a negative regulator of Wnt signaling, for proteolysis. Initial reports indicated that Tnks is important for Wnt pathway activation in cultured human cell lines. However, the requirement for Tnks in physiological settings has been less clear, as subsequent studies in mice, fish and flies suggested that Tnks was either entirely dispensable for Wnt-dependent processes in vivo, or alternatively, had tissue-specific roles. Here, using null alleles, we demonstrate that the regulation of Axin by the highly conserved Drosophila Tnks homolog is essential for the control of ISC proliferation. Furthermore, in the adult intestine, where activity of the Wingless pathway is graded and peaks at each compartmental boundary, Tnks is dispensable for signaling in regions where pathway activity is high, but essential where pathway activity is relatively low. Finally, as observed previously for Wingless pathway components, Tnks activity in absorptive enterocytes controls the proliferation of neighboring ISCs non-autonomously by regulating JAK/STAT signaling. These findings reveal the requirement for Tnks in the control of ISC proliferation and suggest an essential role in the amplification of Wnt signaling, with relevance for development, homeostasis and cancer. PMID:27190037

  2. Microbiota restricts trafficking of bacteria to mesenteric lymph nodes by CX(3)CR1(hi) cells.

    Science.gov (United States)

    Diehl, Gretchen E; Longman, Randy S; Zhang, Jing-Xin; Breart, Beatrice; Galan, Carolina; Cuesta, Adolfo; Schwab, Susan R; Littman, Dan R

    2013-02-01

    The intestinal microbiota has a critical role in immune system and metabolic homeostasis, but it must be tolerated by the host to avoid inflammatory responses that can damage the epithelial barrier separating the host from the luminal contents. Breakdown of this regulation and the resulting inappropriate immune response to commensals are thought to lead to the development of inflammatory bowel diseases such as Crohn's disease and ulcerative colitis. We proposed that the intestinal immune system is instructed by the microbiota to limit responses to luminal antigens. Here we demonstrate in mice that, at steady state, the microbiota inhibits the transport of both commensal and pathogenic bacteria from the lumen to a key immune inductive site, the mesenteric lymph nodes (MLNs). However, in the absence of Myd88 or under conditions of antibiotic-induced dysbiosis, non-invasive bacteria were trafficked to the MLNs in a CCR7-dependent manner, and induced both T-cell responses and IgA production. Trafficking was carried out by CX(3)CR1(hi) mononuclear phagocytes, an intestinal-cell population previously reported to be non-migratory. These findings define a central role for commensals in regulating the migration to the MLNs of CX(3)CR1(hi) mononuclear phagocytes endowed with the ability to capture luminal bacteria, thereby compartmentalizing the intestinal immune response to avoid inflammation. PMID:23334413

  3. Golgi enlargement in Arf-depleted yeast cells is due to altered dynamics of cisternal maturation

    Science.gov (United States)

    Bhave, Madhura; Papanikou, Effrosyni; Iyer, Prasanna; Pandya, Koushal; Jain, Bhawik Kumar; Ganguly, Abira; Sharma, Chandrakala; Pawar, Ketakee; Austin, Jotham; Day, Kasey J.; Rossanese, Olivia W.; Glick, Benjamin S.; Bhattacharyya, Dibyendu

    2014-01-01

    ABSTRACT Regulation of the size and abundance of membrane compartments is a fundamental cellular activity. In Saccharomyces cerevisiae, disruption of the ADP-ribosylation factor 1 (ARF1) gene yields larger and fewer Golgi cisternae by partially depleting the Arf GTPase. We observed a similar phenotype with a thermosensitive mutation in Nmt1, which myristoylates and activates Arf. Therefore, partial depletion of Arf is a convenient tool for dissecting mechanisms that regulate Golgi structure. We found that in arf1Δ cells, late Golgi structure is particularly abnormal, with the number of late Golgi cisternae being severely reduced. This effect can be explained by selective changes in cisternal maturation kinetics. The arf1Δ mutation causes early Golgi cisternae to mature more slowly and less frequently, but does not alter the maturation of late Golgi cisternae. These changes quantitatively explain why late Golgi cisternae are fewer in number and correspondingly larger. With a stacked Golgi, similar changes in maturation kinetics could be used by the cell to modulate the number of cisternae per stack. Thus, the rates of processes that transform a maturing compartment can determine compartmental size and copy number. PMID:24190882

  4. Galvanic Cells

    Science.gov (United States)

    Young, I. G.

    1973-01-01

    Many standard physical chemistry textbooks contain ambiguities which lead to confusion about standard electrode potentials, calculating cell voltages, and writing reactions for galvanic cells. This article shows how standard electrode potentials can be used to calculate cell voltages and deduce cell reactions. (Author/RH)

  5. Translocação e compartimentalização de Zn aplicado via ZnSO4 e ZnEDTA nas folhas de cafeeiro e feijoeiro Translocation and compartmentation of zinc by ZnSO4 e ZnEDTA applied on coffee and bean seedlings leaves

    Directory of Open Access Journals (Sweden)

    Ivan Alencar de Lima Franco

    2005-04-01

    Full Text Available Com o objetivo de avaliar a translocação e a compartimentalização de Zn, aplicado via foliar nas formas de ZnSO4 e ZnEDTA, foram conduzidos dois ensaios em solução nutritiva, em casa de vegetação, utilizando-se mudas de cafeeiro e feijoeiro, em condições de suficiência e deficiência de Zn. O delineamento experimental foi o de blocos ao acaso com quatro repetições em esquema fatorial (2 x 3, correspondendo a dois níveis de Zn na solução nutritiva (suficiência e deficiência e três formas de suprimento de Zn às plantas (ZnSO4 e ZnEDTA a 14mmol L-1 de Zn, ambos em pincelamento na folha, e testemunha sem receber aplicação de Zn. Em ambas as espécies, o ZnSO4 foi mais adsorvido à cutícula da folha do que o ZnEDTA, demonstrando ser a retenção cuticular de Zn importante barreira na sua absorção. O estado nutricional do feijoeiro em Zn afetou o aproveitamento do Zn aplicado via foliar. Tanto a folha pincelada como a planta inteira de feijoeiro adquiriram maior quantidade de Zn do que as do cafeeiro. Em condição de inadequada nutrição em Zn, em ambas as espécies, a utilização de ZnEDTA foi mais eficiente na translocação do Zn. Quando foi aplicado ZnSO4 às folhas de cafeeiro crescidas em solução nutritiva não contendo Zn, houve acúmulo de Zn no caule, indicando que há grande afinidade do Zn2+ do sulfato com as cargas livres existentes nos vasos condutores.Two experiments were conducted aiming to evaluate translocation and compartmentation of ZnSO4 and ZnEDTA applied on leaves of coffee and bean seedlings previously grown under Zn sufficiency or deficiency in nutritive solution in greenhouse. The treatments applied were 14mmol L-1 ZnSO4, ZnEDTA and test without zinc applied on leaves. In both species, ZnSO4 was more retained on leaf cuticle, indicating cuticular zinc retention to be an important barrier in its uptake. The nutritional status of bean plants had a significant effect upon zinc utilization when it was

  6. TNF inhibits Notch-1 in skeletal muscle cells by Ezh2 and DNA methylation mediated repression: implications in duchenne muscular dystrophy.

    Directory of Open Access Journals (Sweden)

    Swarnali Acharyya

    Full Text Available BACKGROUND: Classical NF-kappaB signaling functions as a negative regulator of skeletal myogenesis through potentially multiple mechanisms. The inhibitory actions of TNFalpha on skeletal muscle differentiation are mediated in part through sustained NF-kappaB activity. In dystrophic muscles, NF-kappaB activity is compartmentalized to myofibers to inhibit regeneration by limiting the number of myogenic progenitor cells. This regulation coincides with elevated levels of muscle derived TNFalpha that is also under IKKbeta and NF-kappaB control. METHODOLOGY/PRINCIPAL FINDINGS: Based on these findings we speculated that in DMD, TNFalpha secreted from myotubes inhibits regeneration by directly acting on satellite cells. Analysis of several satellite cell regulators revealed that TNFalpha is capable of inhibiting Notch-1 in satellite cells and C2C12 myoblasts, which was also found to be dependent on NF-kappaB. Notch-1 inhibition occurred at the mRNA level suggesting a transcriptional repression mechanism. Unlike its classical mode of action, TNFalpha stimulated the recruitment of Ezh2 and Dnmt-3b to coordinate histone and DNA methylation, respectively. Dnmt-3b recruitment was dependent on Ezh2. CONCLUSIONS/SIGNIFICANCE: We propose that in dystrophic muscles, elevated levels of TNFalpha and NF-kappaB inhibit the regenerative potential of satellite cells via epigenetic silencing of the Notch-1 gene.

  7. Cell Biochips

    Science.gov (United States)

    Pioufle, B. Le; Picollet-D'Hahan, N.

    A cell biochip is a microsystem, equipped with electronic and microfluidic functions, designed to manipulate or analyse living cells. The first publications in this emerging area of research appeared toward the end of the 1980s. In 1989 Washizu described a biochip designed to fuse two cells by electropermeabilisation of the cytoplasmic membrane [1]. Research centers have devised a whole range of cell chip structures, for simultaneous or sequential analysis of single cells, cell groups, or cell tissues reconstituted on the chip. The cells are arranged in a square array on a parallel cell chip for parallel analysis, while they are examined and processed one by one in a microchannel in the case of a series cell chip. In contrast to these biochips for high-throughput analysis of a large number of cells, single-cell chips focus on the analysis of a single isolated cell. As in DNA microarrays, where a large number of oligonucleotides are ordered in a matrix array, parallel cell chips order living cells in a similar way. At each point of the array, the cells can be isolated, provided that the cell type allows this, e.g., blood cells, or cultivated in groups (most adhesion cells can only survive in groups). The aim is to allow massively parallel analysis or processing. Le Pioufle et al. describe a microdevice for the culture of single cells or small groups of cells in a micropit array [2]. Each pit is equipped to stimulate the cell or group of cells either electrically or fluidically. Among the applications envisaged are gene transfer, cell sorting, and screening in pharmacology. A complementary approach, combining the DNA microarray and cell biochip ideas, has been put forward by Bailey et al. [3]. Genes previously arrayed on the chip transfect the cultured cells on the substrate depending on their position in the array (see Fig. 19.1). This way of achieving differential lipofection on a chip was then taken up again by Yoshikawa et al. [4] with primary cells, more

  8. Cell Wall

    OpenAIRE

    Jamet, Elisabeth; Canut, Hervé; Boudart, Georges; Albenne, Cécile; Pont-Lezica, Rafael F

    2008-01-01

    This chapter covers our present knowledge of cell wall proteomics highlighting the distinctive features of cell walls and cell wall proteins in relation to problems encountered for protein extraction, separation and identification. It provides clues to design strategies for efficient cell wall proteomic studies. It gives an overview of the kinds of proteins that have yet been identified: the expected proteins vs the identified proteins. Finally, the new vision of the cell wall proteome, and t...

  9. Stem Cells

    OpenAIRE

    Madhukar Thakur

    2009-01-01

    Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in ...

  10. Rabies Internalizes into Primary Peripheral Neurons via Clathrin Coated Pits and Requires Fusion at the Cell Body

    Science.gov (United States)

    Piccinotti, Silvia; Whelan, Sean P. J.

    2016-01-01

    The single glycoprotein (G) of rabies virus (RABV) dictates all viral entry steps from receptor engagement to membrane fusion. To study the uptake of RABV into primary neuronal cells in culture, we generated a recombinant vesicular stomatitis virus in which the G protein was replaced with that of the neurotropic RABV CVS-11 strain (rVSV CVS G). Using microfluidic compartmentalized culture, we examined the uptake of single virions into the termini of primary neurons of the dorsal root ganglion and ventral spinal cord. By pharmacologically disrupting endocytosis at the distal neurites, we demonstrate that rVSV CVS G uptake and infection are dependent on dynamin. Imaging of single virion uptake with fluorescent endocytic markers further identifies endocytosis via clathrin-coated pits as the predominant internalization mechanism. Transmission electron micrographs also reveal the presence of viral particles in vesicular structures consistent with incompletely coated clathrin pits. This work extends our previous findings of clathrin-mediated uptake of RABV into epithelial cells to two neuronal subtypes involved in rabies infection in vivo. Chemical perturbation of endosomal acidification in the neurite or somal compartment further shows that establishment of infection requires pH-dependent fusion of virions at the cell body. These findings correlate infectivity to existing single particle evidence of long-range endosomal transport of RABV and clathrin dependent uptake at the plasma membrane. PMID:27463226

  11. Improving the stability of chitosan-gelatin-based hydrogels for cell delivery using transglutaminase and controlled release of doxycycline.

    Science.gov (United States)

    Tormos, Christian J; Abraham, Carol; Madihally, Sundararajan V

    2015-12-01

    Although local cell delivery is an option to repair tissues, particularly using chitosan-based hydrogels, significant attrition of injected cells prior to engraftment has been a problem. To address this problem, we explored the possibility of stabilizing the chitosan-gelatin (CG) injectable hydrogels using (1) controlled release of doxycycline (DOX) to prevent premature degradation due to increased gelatinase activity (MMP-2 and MMP-9), and (2) transglutaminase (TG) to in situ cross-link gelatin to improve the mechanical stability. We prepared DOX-loaded PLGA nanoparticles, loaded into the CG hydrogels, measured DOX release for 5 days, and modeled using a single-compartmental assumption. Next, we assessed the influence of TG and DOX on hydrogel compression properties by incubating hydrogels for 7 days in PBS. We evaluated the effect of these changes on retention of fibroblasts and alterations in MMP-2/MMP-9 activity by seeding 500,000 fibroblasts for 5 days. These results showed that 90 % of DOX released from cross-linked CG hydrogels after 4 days, unlike CG hydrogels where 90 % of DOX was released within the first day. Addition of TG enhanced the CG hydrogel stability significantly. More than 60 % of seeded fibroblasts were recovered from the CG-TG hydrogels at day 5, unlike 40 % recovered from CG-hydrogels. Inhibition of MMP-2/MMP-9 were observed. In summary, controlled release of DOX from CG hydrogels cross-linked with TG shows a significant potential as a carrier for cell delivery.

  12. Ceramide limits phosphatidylinositol-3-kinase C2β-controlled cell motility in ovarian cancer: potential of ceramide as a metastasis-suppressor lipid.

    Science.gov (United States)

    Kitatani, K; Usui, T; Sriraman, S K; Toyoshima, M; Ishibashi, M; Shigeta, S; Nagase, S; Sakamoto, M; Ogiso, H; Okazaki, T; Hannun, Y A; Torchilin, V P; Yaegashi, N

    2016-05-01

    Targeting cell motility, which is required for dissemination and metastasis, has therapeutic potential for ovarian cancer metastasis, and regulatory mechanisms of cell motility need to be uncovered for developing novel therapeutics. Invasive ovarian cancer cells spontaneously formed protrusions, such as lamellipodia, which are required for generating locomotive force in cell motility. Short interfering RNA screening identified class II phosphatidylinositol 3-kinase C2β (PI3KC2β) as the predominant isoform of PI3K involved in lamellipodia formation of ovarian cancer cells. The bioactive sphingolipid ceramide has emerged as an antitumorigenic lipid, and treatment with short-chain C6-ceramide decreased the number of ovarian cancer cells with PI3KC2β-driven lamellipodia. Pharmacological analysis demonstrated that long-chain ceramide regenerated from C6-ceramide through the salvage/recycling pathway, at least in part, mediated the action of C6-ceramide. Mechanistically, ceramide was revealed to interact with the PIK-catalytic domain of PI3KC2β and affect its compartmentalization, thereby suppressing PI3KC2β activation and its driven cell motility. Ceramide treatment also suppressed cell motility promoted by epithelial growth factor, which is a prometastatic factor. To examine the role of ceramide in ovarian cancer metastasis, ceramide liposomes were employed and confirmed to suppress cell motility in vitro. Ceramide liposomes had an inhibitory effect on peritoneal metastasis in a murine xenograft model of human ovarian cancer. Metastasis of PI3KC2β knocked-down cells was insensitive to treatment with ceramide liposomes, suggesting specific involvement of ceramide interaction with PI3KC2β in metastasis suppression. Our study identified ceramide as a bioactive lipid that limits PI3KC2β-governed cell motility, and ceramide is proposed to serve as a metastasis-suppressor lipid in ovarian cancer. These findings could be translated into developing ceramide

  13. Identification of active elementary flux modes in mitochondria using selectively permeabilized CHO cells.

    Science.gov (United States)

    Nicolae, Averina; Wahrheit, Judith; Nonnenmacher, Yannic; Weyler, Christian; Heinzle, Elmar

    2015-11-01

    Metabolic compartmentation is a key feature of mammalian cells. Mitochondria are the powerhouse of eukaryotic cells, responsible for respiration and the TCA cycle. We accessed the mitochondrial metabolism of the economically important Chinese hamster ovary (CHO) cells using selective permeabilization. We tested key substrates without and with addition of ADP. Based on quantified uptake and production rates, we could determine the contribution of different elementary flux modes to the metabolism of a substrate or substrate combination. ADP stimulated the uptake of most metabolites, directly by serving as substrate for the respiratory chain, thus removing the inhibitory effect of NADH, or as allosteric effector. Addition of ADP favored substrate metabolization to CO2 and did not enhance the production of other metabolites. The controlling effect of ADP was more pronounced when we supplied metabolites to the first part of the TCA cycle: pyruvate, citrate, α-ketoglutarate and glutamine. In the second part of the TCA cycle, the rates were primarily controlled by the concentrations of C4-dicarboxylates. Without ADP addition, the activity of the pyruvate carboxylase-malate dehydrogenase-malic enzyme cycle consumed the ATP produced by oxidative phosphorylation, preventing its accumulation and maintaining metabolic steady state conditions. Aspartate was taken up only in combination with pyruvate, whose uptake also increased, a fact explained by complex regulatory effects. Isocitrate dehydrogenase and α-ketoglutarate dehydrogenase were identified as the key regulators of the TCA cycle, confirming existent knowledge from other cells. We have shown that selectively permeabilized cells combined with elementary mode analysis allow in-depth studying of the mitochondrial metabolism and regulation.

  14. Ca²⁺ signaling and regulation of fluid secretion in salivary gland acinar cells.

    Science.gov (United States)

    Ambudkar, Indu S

    2014-06-01

    Neurotransmitter stimulation of plasma membrane receptors stimulates salivary gland fluid secretion via a complex process that is determined by coordinated temporal and spatial regulation of several Ca(2+) signaling processes as well as ion flux systems. Studies over the past four decades have demonstrated that Ca(2+) is a critical factor in the control of salivary gland function. Importantly, critical components of this process have now been identified, including plasma membrane receptors, calcium channels, and regulatory proteins. The key event in activation of fluid secretion is an increase in intracellular [Ca(2+)] ([Ca(2+)]i) triggered by IP3-induced release of Ca(2+) from ER via the IP3R. This increase regulates the ion fluxes required to drive vectorial fluid secretion. IP3Rs determine the site of initiation and the pattern of [Ca(2+)]i signal in the cell. However, Ca(2+) entry into the cell is required to sustain the elevation of [Ca(2+)]i and fluid secretion. This Ca(2+) influx pathway, store-operated calcium influx pathway (SOCE), has been studied in great detail and the regulatory mechanisms as well as key molecular components have now been identified. Orai1, TRPC1, and STIM1 are critical components of SOCE and among these, Ca(2+) entry via TRPC1 is a major determinant of fluid secretion. The receptor-evoked Ca(2+) signal in salivary gland acinar cells is unique in that it starts at the apical pole and then rapidly increases across the cell. The basis for the polarized Ca(2+) signal can be ascribed to the polarized arrangement of the Ca(2+) channels, transporters, and signaling proteins. Distinct localization of these proteins in the cell suggests compartmentalization of Ca(2+) signals during regulation of fluid secretion. This chapter will discuss new concepts and findings regarding the polarization and control of Ca(2+) signals in the regulation of fluid secretion.

  15. Engineering cell-cell signaling.

    Science.gov (United States)

    Blagovic, Katarina; Gong, Emily S; Milano, Daniel F; Natividad, Robert J; Asthagiri, Anand R

    2013-10-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling on the basis of quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilize synthetic cells, advanced 'chassis' and predictive modeling to engineer the form and function of living tissues.

  16. Lipid raft-mediated Fas/CD95 apoptotic signaling in leukemic cells and normal leukocytes and therapeutic implications.

    Science.gov (United States)

    Gajate, Consuelo; Mollinedo, Faustino

    2015-11-01

    Plasma membrane is now recognized to contain tightly packed cholesterol/sphingolipid-rich domains, known as lipid or membrane rafts, which are more ordered than the surrounding lipid bilayer. Lipid rafts are crucial for the compartmentalization of signaling processes in the membrane, mostly involved in cell survival and immune response. However, in the last 15 years, a large body of evidence has also identified raft platforms as scaffolds for the recruitment and clustering of death receptor Fas/CD95 and downstream signaling molecules, leading to the concept of death-promoting lipid rafts. This raft-Fas/CD95 coclustering was first described at the early 2000s as the underlying mechanism for the proapoptotic action of the alkylphospholipid analog edelfosine in leukemic cells, hence facilitating protein-protein interactions and conveying apoptotic signals independently of Fas/CD95 ligand. Edelfosine induces apoptosis in hematologic cancer cells and activated T-lymphocytes. Fas/CD95 raft coclustering is also promoted by Fas/CD95 ligand, agonistic Fas/CD95 antibodies, and additional antitumor drugs. Thus, death receptor recruitment in rafts is a physiologic process leading to cell demise that can be pharmacologically modulated. This redistribution and local accumulation of apoptotic molecules in membrane rafts, which are usually accompanied by displacement of survival signaling molecules, highlight how alterations in the apoptosis/survival signaling balance in specialized membrane regions modulate cell fate. Membrane rafts might also modulate apoptotic and nonapoptotic death receptor signaling. Here, we discuss the role of lipid rafts in Fas/CD95-mediated apoptotic cell signaling in hematologic cancer cells and normal leukocytes, with a special emphasis on their involvement as putative therapeutic targets in cancer and autoimmune diseases.

  17. Cell Motility

    CERN Document Server

    Lenz, Peter

    2008-01-01

    Cell motility is a fascinating example of cell behavior which is fundamentally important to a number of biological and pathological processes. It is based on a complex self-organized mechano-chemical machine consisting of cytoskeletal filaments and molecular motors. In general, the cytoskeleton is responsible for the movement of the entire cell and for movements within the cell. The main challenge in the field of cell motility is to develop a complete physical description on how and why cells move. For this purpose new ways of modeling the properties of biological cells have to be found. This long term goal can only be achieved if new experimental techniques are developed to extract physical information from these living systems and if theoretical models are found which bridge the gap between molecular and mesoscopic length scales. Cell Motility gives an authoritative overview of the fundamental biological facts, theoretical models, and current experimental developments in this fascinating area.

  18. Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2012-04-01

    Full Text Available The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.Article in Lithuanian

  19. Solar cells

    Science.gov (United States)

    Cuquel, A.; Roussel, M.

    The physical and electronic characteristics of solar cells are discussed in terms of space applications. The principles underlying the photovoltaic effect are reviewed, including an analytic model for predicting the performance of individual cells and arrays of cells. Attention is given to the effects of electromagnetic and ionizing radiation, micrometeors, thermal and mechanical stresses, pollution and degassing encountered in space. The responses of different types of solar cells to the various performance-degrading agents are examined, with emphasis on techniques for quality assurance in the manufacture and mounting of Si cells.

  20. Engineering Cell-Cell Signaling

    OpenAIRE

    Blagovic, Katarina; Gong, Emily S.; Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R

    2013-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cel...

  1. Alterations in regulatory T cells induced by specific oligosaccharides improve vaccine responsiveness in mice.

    Directory of Open Access Journals (Sweden)

    Marcel A Schijf

    Full Text Available Prophylactic vaccinations are generally performed to protect naïve individuals with or without suppressed immune responsiveness. In a mouse model for Influenza vaccinations the specific alterations of CD4(+CD25(+Foxp3(+ regulatory T-cells (Tregs in the immune modulation induced by orally supplied oligosaccharides containing scGOS/lcFOS/pAOS was assessed. This dietary intervention increased vaccine specific DTH responses. In addition, a significant increased percentage of T-bet(+ (Th1 activated CD69(+CD4(+ T cells (p<0.001 and reduced percentage of Gata-3(+ (Th2 activated CD69(+CD4(+T cells (p<0.001 was detected in the mesenteric lymph nodes (MLN of mice receiving scGOS/lcFOS/pAOS compared to control mice. Although no difference in the number or percentage of Tregs (CD4(+Foxp3(+ could be determined after scGOS/lcFOS/pAOS intervention, the percentage of CXCR3 (+ /T-bet(+ (Th1-Tregs was significantly reduced (p<0.05 in mice receiving scGOS/lcFOS/pAOS as compared to mice receiving placebo diets. Moreover, although no absolute difference in suppressive capacity could be detected, an alteration in cytokine profile suggests a regulatory T cell shift towards a reducing Th1 suppression profile, supporting an improved vaccination response.These data are indicative for improved vaccine responsiveness due to reduced Th1 suppressive capacity in the Treg population of mice fed the oligosaccharide specific diet, showing compartmentalization within the Treg population. The modulation of Tregs to control immune responses provides an additional arm of intervention using alternative strategies possibly leading to the development of improved vaccines.

  2. Localization of a bacterial group II intron-encoded protein in eukaryotic nuclear splicing-related cell compartments.

    Directory of Open Access Journals (Sweden)

    Rafael Nisa-Martínez

    Full Text Available Some bacterial group II introns are widely used for genetic engineering in bacteria, because they can be reprogrammed to insert into the desired DNA target sites. There is considerable interest in developing this group II intron gene targeting technology for use in eukaryotes, but nuclear genomes present several obstacles to the use of this approach. The nuclear genomes of eukaryotes do not contain group II introns, but these introns are thought to have been the progenitors of nuclear spliceosomal introns. We investigated the expression and subcellular localization of the bacterial RmInt1 group II intron-encoded protein (IEP in Arabidopsis thaliana protoplasts. Following the expression of translational fusions of the wild-type protein and several mutant variants with EGFP, the full-length IEP was found exclusively in the nucleolus, whereas the maturase domain alone targeted EGFP to nuclear speckles. The distribution of the bacterial RmInt1 IEP in plant cell protoplasts suggests that the compartmentalization of eukaryotic cells into nucleus and cytoplasm does not prevent group II introns from invading the host genome. Furthermore, the trafficking of the IEP between the nucleolus and the speckles upon maturase inactivation is consistent with the hypothesis that the spliceosomal machinery evolved from group II introns.

  3. Calcium Forms,Subcelluar Distribution and Ultrastructure of Pulp Cells as Influenced by Calcium Deficiency in Apple (Malus pumila) Fruits

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-hui; ZHOU Wei

    2004-01-01

    Calcium in Red Fuji and Starkrimson apples during storage were fractionated by sequent extracting. Localization and distribution of calcium and influence of calcium nutrition on cell ultrastructure were observed by transmission electron microscopy combined with in situ precipitation of calcium with an improved method of potassium pyroantimonate technique. Results indicated that spraying calcium solution on surface of young fruits increased contents of calcium in all forms. During storage, contents of soluble calcium and pectic calcium declined and thosein calcium phosphate, calcium oxalate and calcium silicate increased. Calcium contents of Red Fuji in all forms were higher than those of Starkrimson, indicating that calcium accumulating capability of Red Fuji fruits preceded that of Starkrimson. Under transmission electron microscopy, calcium antimonite precipitates (CaAP) was mainly distributed in cell wall, tonoplast, nuclear membrane and nucleoplasm,much more CaAP deposited in vacuole. Calcium deficiency during storage leads to decrease of CaAP in locations mentioned above, disappearance of compartmentation, and entrance of CaAP to cytoplasm. Transformation from soluble calcium and pectic calcium to calcium phosphate,oxalate and damages of biomembranes structuraly and functionally resulted from calcium deficiency during storage were the crucial causation of physiological disorder.

  4. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    Energy Technology Data Exchange (ETDEWEB)

    Kosicek, Marko, E-mail: marko.kosicek@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Malnar, Martina, E-mail: martina.malnar@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia); Goate, Alison, E-mail: goate@icarus.wustl.edu [Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110 (United States); Hecimovic, Silva, E-mail: silva.hecimovic@irb.hr [Division of Molecular Medicine, Ruder Boskovic Institute, Bijenicka 54, 10000 Zagreb (Croatia)

    2010-03-12

    It has been suggested that cholesterol may modulate amyloid-{beta} (A{beta}) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD ({beta}-amyloid precursor protein (APP), {beta}-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/A{beta} formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1{sup -/-} cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, {gamma}-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards A{beta} occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  5. Stem Cells

    Directory of Open Access Journals (Sweden)

    Madhukar Thakur

    2015-02-01

    Full Text Available Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in the body. Often called as Magic Seeds, stem cells are produced in bone marrow and circulate in blood, albeit at a relatively low concentration. These virtues together with the ability of stem cells to grow in tissue culture have paved the way for their applications to generate new and healthy tissues and to replace diseased or injured human organs. Although possibilities of stem cell applications are many, much remains yet to be understood of these remarkable magic seeds. Conclusion: This presentation shall briefly cover the origin of stem cells, the pros and cons of their growth and division, their potential application, and shall outline some examples of the contributions of radiolabeled stem cells, in this rapidly growing branch of biomedical science

  6. Types of Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... stem cells blog from the International Society for Stem Cell Research. Learn About Stem Cells From Lab to You ...

  7. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  8. Cell suicide

    International Nuclear Information System (INIS)

    In the fight of the cell against the damages caused to its DNA by genotoxic agents and specially by ionizing radiations, the p53 protein plays a central part. It intervenes in the proliferation control and the differentiation but also in the keeping of genome integrity. It can direct the damages cells toward suicide, or apoptosis, to avoid the risk of tumor appearance that would be fatal to the whole organism. That is by the disordered state of cells suicide programs that the tumor cells are going to develop. The knowledge of apoptosis mechanisms, to eventually start them on demand, rises up broad hopes in the cancer therapy. (N.C.)

  9. Reprogrammed Pluripotent Stem Cells from Somatic Cells

    OpenAIRE

    Kim, Jong Soo; Choi, Hyun Woo; Choi, Sol; Do, Jeong Tae

    2011-01-01

    Pluripotent stem cells, such as embryonic stem (ES) cells, can differentiate into all cell types. So, these cells can be a biological resource for regenerative medicine. However, ES cells known as standard pluripotent cells have problem to be used for cell therapy because of ethical issue of the origin and immune response on the graft. Hence, recently reprogrammed pluripotent cells have been suggested as an alternative source for regenerative medicine. Somatic cells can acquire the ES cell-li...

  10. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  11. Localization of adenylyl cyclase isoforms and G protein-coupled receptors in vascular smooth muscle cells: expression in caveolin-rich and noncaveolin domains.

    Science.gov (United States)

    Ostrom, Rennolds S; Liu, Xiaoqiu; Head, Brian P; Gregorian, Caroline; Seasholtz, Tammy M; Insel, Paul A

    2002-11-01

    A number of different agonists activate G protein-coupled receptors to stimulate adenylyl cyclase (AC), increase cAMP formation, and promote relaxation in vascular smooth muscle. To more fully understand this stimulation of AC, we assessed the expression, regulation, and compartmentation of AC isoforms in rat aortic smooth muscle cells (RASMC). Reverse transcription-polymerase chain reaction detected expression of AC3, AC5, and AC6 mRNA, whereas immunoblot analysis indicated expression of AC3 and AC5/6 protein primarily in caveolin-rich membrane (cav) fractions relative to noncaveolin (noncav) fractions. Beta(1)-adrenergic receptors (AR), beta(2)AR, and G(s) were detected in both cav and noncav fractions, whereas the prostanoid receptors EP(2)R and EP(4)R were excluded from cav fractions. We used an adenoviral construct to increase AC6 expression. Overexpressed AC6 localized only in noncav fractions. Two-fold overexpression of AC6 caused enhancement of forskolin-, isoproterenol- and prostaglandin E(2)-stimulated cAMP formation but no changes in basal levels of cAMP. At higher levels of AC6 overexpression, basal and adenosine receptor-stimulated cAMP levels were increased. Stimulation of cAMP levels by agents that increase Ca(2+) in native cells was consistent with the expression of AC3, but overexpression of AC6, which is inhibited by Ca(2+), blunted the Ca(2+)-stimulable cAMP response. These data indicate that: 1) RASMC express multiple AC isoforms that localize in both caveolin-rich and noncaveolin domains, 2) expression of AC6 in non-caveolin-rich membranes can increase basal levels of cAMP and response to several stimulatory agonists, and 3) Ca(2+)-mediated regulation of cAMP formation depends upon expression of different AC isoforms in RASMC. Compartmentation of GPCRs and AC is different in cardiomyocytes than in RASMC, indicating that targeting of these components to caveolin-rich membranes can be cell-specific. Moreover, our results imply that the

  12. [Cell cultures].

    Science.gov (United States)

    Cipro, Simon; Groh, Tomáš

    2014-01-01

    Cell or tissue cultures (both terms are interchangeable) represent a complex process by which eukaryotic cells are maintained in vitro outside their natural environment. They have a broad usage covering not only scientific field but also diagnostic one since they represent the most important way of monoclonal antibodies production which are used for both diagnostic and therapeutic purposes. Cell cultures are also used as a "cultivation medium" in virology and for establishing proliferating cells in cytodiagnostics. They are well-established and easy-to-handle models in the area of research, e.g. as a precious source of nucleic acids or proteins. This paper briefly summarizes their importance and methods as well as the pitfalls of the cultivation and new trends in this field. PMID:24624984

  13. Fuel cells

    Directory of Open Access Journals (Sweden)

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  14. Dry cell battery poisoning

    Science.gov (United States)

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  15. Polymersomes containing iron sulfide (FeS) as primordial cell model : for the investigation of energy providing redox reactions.

    Science.gov (United States)

    Alpermann, Theodor; Rüdel, Kristin; Rüger, Ronny; Steiniger, Frank; Nietzsche, Sandor; Filiz, Volkan; Förster, Stephan; Fahr, Alfred; Weigand, Wolfgang

    2011-04-01

    According to Wächtershäuser's "Iron-Sulfur-World" one major requirement for the development of life on the prebiotic Earth is compartmentalization. Vesicles spontaneously formed from amphiphilic components containing a specific set of molecules including sulfide minerals may have lead to the first autotrophic prebiotic units. The iron sulfide minerals may have been formed by geological conversions in the environment of deep-sea volcanos (black smokers), which can be observed even today. Wächtershäuser postulated the evolution of chemical pathways as fundamentals of the origin of life on earth. In contrast to the classical Miller-Urey experiment, depending on external energy sources, the "Iron-Sulfur-World" is based on the catalytic and energy reproducing redox system FeS+H2S-->FeS2+H2. The energy release out of this redox reaction (∆RG°=-38 kJ/mol, pH 0) could be the cause for the subsequent synthesis of complex organic molecules and the precondition for the development of more complex units similar to cells known today. Here we show the possibility for precipitating iron sulfide inside vesicles composed of amphiphilic block-copolymers as a model system for a first prebiotic unit. Our findings could be an indication for a chemoautotrophic FeS based origin of life. PMID:20697814

  16. Glucose alleviates cadmium toxicity by increasing cadmium fixation in root cell wall and sequestration into vacuole in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yuan-Zhi Shi; Xiao-Fang Zhu; Jiang-Xue Wan; Gui-Xin Li; Shao-Jian Zheng

    2015-01-01

    Glucose (Glu) is involved in not only plant physiological and developmental events but also plant responses to abiotic stresses. Here, we found that the exogenous Glu improved root and shoot growth, reduced shoot cadmium (Cd) concentration, and rescued Cd-induced chlorosis in Arabidopsis thaliana (Columbia ecotype, Col-0) under Cd stressed conditions. Glucose increased Cd retained in the roots, thus reducing its translocation from root to shoot significantly. The most Cd retained in the roots was found in the hemicellulose 1. Glucose combined with Cd (Glu þ Cd) treatment did not affect the content of pectin and its binding capacity of Cd while it increased the content of hemicelluloses 1 and the amount of Cd retained in it significantly. Furthermore, Leadmium Green staining indicated that more Cd was compartmented into vacuoles in Glu þ Cd treatment compared with Cd treatment alone, which was in accordance with the significant upregulation of the expression of tonoplast-localized metal transporter genes, suggesting that com-partmentation of Cd into vacuoles also contributes to the Glu-alleviated Cd toxicity. Taken together, we demonstrated that Glu-alleviated Cd toxicity is mediated through increas-ing Cd fixation in the root cell wall and sequestration into the vacuoles.

  17. Cell sorting by deterministic cell rolling

    OpenAIRE

    Choi, Sungyoung; Karp, Jeffrey M.; Karnik, Rohit

    2011-01-01

    This communication presents the concept of “deterministic cell rolling”, which leverages transient cell-surface molecular interactions that mediate cell rolling to sort cells with high purity and efficiency in a single step.

  18. Biocompatibility, endocytosis, and intracellular trafficking of mesoporous silica and polystyrene nanoparticles in ovarian cancer cells: effects of size and surface charge groups

    Science.gov (United States)

    Ekkapongpisit, Maneerat; Giovia, Antonino; Follo, Carlo; Caputo, Giuseppe; Isidoro, Ciro

    2012-01-01

    Background and methods Nanoparticles engineered to carry both a chemotherapeutic drug and a sensitive imaging probe are valid tools for early detection of cancer cells and to monitor the cytotoxic effects of anticancer treatment simultaneously. Here we report on the effect of size (10–30 nm versus 50 nm), type of material (mesoporous silica versus polystyrene), and surface charge functionalization (none, amine groups, or carboxyl groups) on biocompatibility, uptake, compartmentalization, and intracellular retention of fluorescently labeled nanoparticles in cultured human ovarian cancer cells. We also investigated the involvement of caveolae in the mechanism of uptake of nanoparticles. Results We found that mesoporous silica nanoparticles entered via caveolae-mediated endocytosis and reached the lysosomes; however, while the 50 nm nanoparticles permanently resided within these organelles, the 10 nm nanoparticles soon relocated in the cytoplasm. Naked 10 nm mesoporous silica nanoparticles showed the highest and 50 nm carboxyl-modified mesoporous silica nanoparticles the lowest uptake rates, respectively. Polystyrene nanoparticle uptake also occurred via a caveolae-independent pathway, and was negatively affected by serum. The 30 nm carboxyl-modified polystyrene nanoparticles did not localize in lysosomes and were not toxic, while the 50 nm amine-modified polystyrene nanoparticles accumulated within lysosomes and eventually caused cell death. Ovarian cancer cells expressing caveolin-1 were more likely to endocytose these nanoparticles. Conclusion These data highlight the importance of considering both the physicochemical characteristics (ie, material, size and surface charge on chemical groups) of nanoparticles and the biochemical composition of the cell membrane when choosing the most suitable nanotheranostics for targeting cancer cells. PMID:22904626

  19. Remodeling of B-Cell Subsets in Blood during Pegylated IFNα-2a Therapy in Patients with Chronic Hepatitis B Infection.

    Science.gov (United States)

    Aspord, Caroline; Bruder Costa, Juliana; Jacob, Marie-Christine; Dufeu-Duchesne, Tania; Bertucci, Inga; Pouget, Noelle; Brevot-Lutton, Ophelie; Zoulim, Fabien; Bourliere, Marc; Plumas, Joel; Leroy, Vincent

    2016-01-01

    The ultimate goal of pegylated interferon-alfa-2a (Peg-IFN-α) therapy in chronic hepatitis B (CHB) infection is HBsAg seroconversion. Even though B cells are major mediators of a positive clinical outcome, their modulation during Peg-IFN-α therapy has not yet been described. We investigated here the effects of Peg-IFN-α on eight circulating B-cell subsets thanks to an original multi-gating approach based on CD19, CD27, IgD, CD10, and CD38 markers in patients with CHB treated with nucleos(t)ide analog alone or in combination with Peg-IFN-α. These dynamic changes were analyzed during the 48-weeks of Peg-IFN-α therapy and up to 2 years after the cessation of treatment. The CD19+CD27-IgD+CD10+CD38high transitional B cells and the CD19+CD27+IgD-CD10-CD38high plasmablasts continuously increased, whereas the CD19+CD27-IgD+CD10-CD38low naive, CD19+CD27+IgD+ natural memory, and CD19+CD27+IgD-CD10-CD38low post-germinal center B cells decreased during the course of Peg-IFNα treatment. Such modulations correlated with a sustained increase in sCD30 levels and the decrease in plasma HBsAg. However, no seroconversion occurred and all parameters returned to baseline after the stop of the treatment. Peg-IFN-α therapy mediates a remodeling of B-cell compartmentalization, without clinical relevance. Our study provides new insights into the immunomodulatory effects of Peg-IFN-α on circulating B-cells, and questioned the benefit of the add-on Peg-IFN-α treatment in CHB. PMID:27281019

  20. Electrochemical cell

    Science.gov (United States)

    Nagy, Zoltan; Yonco, Robert M.; You, Hoydoo; Melendres, Carlos A.

    1992-01-01

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90.degree. in either direction while maintaining the working and counter electrodes submerged in the electrolyte.

  1. A simulation study on the effects of dendritic morphology on layer V PFC pyramidal cell firing behavior

    Directory of Open Access Journals (Sweden)

    Maria Psarrou

    2014-03-01

    Full Text Available The majority of neuronal cells found in the cerebral cortex are pyramidal neurons. Their function has been associated with higher cognitive and emotional functions. Pyramidal neurons have a characteristic structure, consisting of a triangular shaped soma whereon descend two extended and complex dendritic trees, and a long bifurcated axon. All the morphological components of the pyramidal neurons exhibit significant variability across different brain areas and layers. Pyramidal cells receive numerous synaptic inputs along their structure, integration of which in space and in time generates local dendritic spikes that shape their firing pattern. In addition, synaptic integration is influenced by voltage-gated and ion channels, which are expressed in a large repertoire by pyramidal neurons. Electrophysiological categories of pyramidal cells can be established, based on the action potential frequency, generated from a fixed somatic stimulus: (1 cells that fire repetitive action potentials (Regular Spiking – RS, (2 cells that fire clusters of 2 – 5 action potentials with short ISIs (Intrinsic Bursting – IB, and (3 cells that fire in repetitive clusters of 2 – 5 action potentials with short ISIs (Repetitive Oscillatory Bursts – ROB. In vitro and in silico scientific studies, correlate the firing patterns of the pyramidal neurons to their morphological features. This study provides a quantitatively analysis via compartmental neuronal modelling of the effects of dendritic morphology and distribution and concentration of ionic mechanisms, along the basal and/or apical dendrites on the firing behavior of a 112-set of layer V rat PFC pyramidal cells. We focus on how particular morphological and passive features of the dendritic trees shape the neuronal firing patterns. Our results suggest that specific morphological parameters (such as total length, volume and branch number can discriminate the cells as RS or IB, regardless of what is the

  2. Solar cells

    Science.gov (United States)

    Treble, F. C.

    1980-11-01

    The history, state of the art, and future prospects of solar cells are reviewed. Solar cells are already competitive in a wide range of low-power applications, and during the 1980's they are expected to become cheaper to run than diesel or gasoline generators, the present mainstay of isolated communities. At this stage they will become attractive for water pumping, irrigation, and rural electrification, particularly in developing countries. With further cost reduction, they may be used to augment grid supplies in domestic, commercial, institutional, and industrial premises. Cost reduction to the stage where photovoltaics becomes economic for large-scale power generation in central stations depends on a technological breakthrough in the development of thin-film cells. DOE aims to reach this goal by 1990, so that by the end of the century about 20% of the estimated annual additions to their electrical generating capacity will be photovoltaic.

  3. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    In his influential essay on markets, An essay on framing and overflowing (1998), Michel Callon writes that `the growing complexity of industrialized societies [is] due in large part to the movements of the technosciences, which are causing connections and interdependencies to proliferate'. This p...... and tantalizing than stem cells, in research, in medicine, or as products.......'. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...

  4. Cell Libraries

    Science.gov (United States)

    1994-01-01

    A NASA contract led to the development of faster and more energy efficient semiconductor materials for digital integrated circuits. Gallium arsenide (GaAs) conducts electrons 4-6 times faster than silicon and uses less power at frequencies above 100-150 megahertz. However, the material is expensive, brittle, fragile and has lacked computer automated engineering tools to solve this problem. Systems & Processes Engineering Corporation (SPEC) developed a series of GaAs cell libraries for cell layout, design rule checking, logic synthesis, placement and routing, simulation and chip assembly. The system is marketed by Compare Design Automation.

  5. Solar cells

    International Nuclear Information System (INIS)

    A method of producing solar cells is described which consists of producing a substantially monocrystalline tubular body of silicon or other suitable semiconductor material, treating this body to form an annular rectifying junction and then cutting it longitudinally to form a number of nearly flat ribbons from which the solar cells are fabricated. The P=N rectifying junction produced by the formation of silicon dioxide on the layers at the inner and outer surfaces of the body can be formed by ion-implantation or diffusion. (U.K.)

  6. Learn About Stem Cells

    Science.gov (United States)

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... ISSCR Get Involved Media © 2015 International Society for Stem Cell Research Terms of Use Disclaimer Privacy Policy

  7. Stem Cell Basics

    Science.gov (United States)

    ... Information Stem Cell Basics Stem Cell Basics: Introduction Stem Cell Information General Information Clinical Trials Funding Information Current Research Policy Glossary Site Map Stem Cell Basics Introduction: What are stem cells, and why ...

  8. Stem Cell Information: Glossary

    Science.gov (United States)

    ... Neurons Oligodendrocyte Parthenogenesis Passage Pluripotent Polar body Preimplantation Proliferation Regenerative medicine Reproductive cloning Signals Somatic cell Somatic cell nuclear transfer (SCNT) Somatic (adult) stem cell Stem cells Stromal cells Subculturing Surface markers ...

  9. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  10. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...... and nuclear fuel-based energy technologies....

  11. Potent Cells

    Science.gov (United States)

    Liu, Dennis

    2007-01-01

    It seems hard to believe that Dolly the cloned sheep was born 10 years ago, kindling furious arguments over the prospects and ethics of cloning a human. Today, the controversy over cloning is entwined, often confused, with concerns over the use of human embryonic stem cells. Most people are unclear what cloning is, and they know even less when it…

  12. Electrochemical Cell

    DEFF Research Database (Denmark)

    1999-01-01

    The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0

  13. Cell Docking, Movement and Cell-Cell Interactions of Heterogeneous Cell Suspensions in a Cell Manipulation Microdevice

    OpenAIRE

    Long-Sun Huang; Yu-Hung Wang; Yu-Wei Chung; Fei-Lung Lai; Shiaw-Min Hwang

    2011-01-01

    This study demonstrates a novel cell manipulation microdevice for cell docking, culturing, cell-cell contact and interaction by microfluidic manipulation of heterogeneous cell suspensions. Heterogeneous cell suspensions include disparate blood cells of natural killer cells and leukemia cancer cells for immune cell transplantation therapy. However, NK cell alloreactivity from different healthy donors present various recovery response levels. Little is still known about the interactions and cyt...

  14. Peptide-coated semiconductor quantum dots and their applications in biological imaging of single molecules in live cells and organisms

    Science.gov (United States)

    Pinaud, Fabien Florent

    2007-12-01

    A new surface chemistry has been developed for the solubilization and biofunctionalization of inorganic semiconductor nanocrystals fluorescent probes, also known as quantum dots. This chemistry is based on the surface coating of quantum dots with custom-designed polycysteine peptides and yields water-soluble, small, monodispersed and colloidally stable probes that remain bright and photostable in complex biological milieus. This peptide coating strategy was successfully tested on several types of core and core-shell quantum dots emitting from the visible (e.g. CdSe/ZnS) to the NIR spectrum range (e.g. CdTe/CdSe/ZnS). By taking advantage of the versatile physico-chemical properties of peptides, a peptide "toolkit" was designed and employed to impart several biological functions to individual quantum dots and control their biochemical activity at the nanometer scale. These biofunctionalized peptide-coated quantum dots were exploited in very diverse biological applications. Near-infrared emitting quantum dot probes were engineered with optimized blood circulation and biodistribution properties for in vivo animal imaging. Visible emitting quantum dots were used for single molecule tracking of raft-associated GPI-anchored proteins in live cells. This last application revealed the presence of discrete and non-caveolar lipid microdomains capable of impeding free lateral diffusions in the plasma membrane of Hela cells. Imaging and tracking of peptide-coated quantum dots provided the first direct evidence that microdomains having the composition and behavior expected for lipid rafts can induce molecular compartmentalization in the membrane of living cells.

  15. Detection of differentially regulated subsarcolemmal calcium signals activated by vasoactive agonists in rat pulmonary artery smooth muscle cells

    Science.gov (United States)

    Subedi, Krishna P.; Paudel, Omkar

    2013-01-01

    Intracellular calcium (Ca2+) plays pivotal roles in distinct cellular functions through global and local signaling in various subcellular compartments, and subcellular Ca2+ signal is the key factor for independent regulation of different cellular functions. In vascular smooth muscle cells, subsarcolemmal Ca2+ is an important regulator of excitation-contraction coupling, and nucleoplasmic Ca2+ is crucial for excitation-transcription coupling. However, information on Ca2+ signals in these subcellular compartments is limited. To study the regulation of the subcellular Ca2+ signals, genetically encoded Ca2+ indicators (cameleon), D3cpv, targeting the plasma membrane (PM), cytoplasm, and nucleoplasm were transfected into rat pulmonary arterial smooth muscle cells (PASMCs) and Ca2+ signals were monitored using laser scanning confocal microscopy. In situ calibration showed that the Kd for Ca2+ of D3cpv was comparable in the cytoplasm and nucleoplasm, but it was slightly higher in the PM. Stimulation of digitonin-permeabilized cells with 1,4,5-trisphosphate (IP3) elicited a transient elevation of Ca2+ concentration with similar amplitude and kinetics in the nucleoplasm and cytoplasm. Activation of G protein-coupled receptors by endothelin-1 and angiotensin II preferentially elevated the subsarcolemmal Ca2+ signal with higher amplitude in the PM region than the nucleoplasm and cytoplasm. In contrast, the receptor tyrosine kinase activator, platelet-derived growth factor, elicited Ca2+ signals with similar amplitudes in all three regions, except that the rise-time and decay-time were slightly slower in the PM region. These data clearly revealed compartmentalization of Ca2+ signals in the subsarcolemmal regions and provide the basis for further investigations of differential regulation of subcellular Ca2+ signals in PASMCs. PMID:24352334

  16. The ancient Virus World and evolution of cells

    Directory of Open Access Journals (Sweden)

    Dolja Valerian V

    2006-09-01

    with a specific model of precellular evolution under which the primordial gene pool dwelled in a network of inorganic compartments. Somewhat paradoxically, under this scenario, we surmise that selfish genetic elements ancestral to viruses evolved prior to typical cells, to become intracellular parasites once bacteria and archaea arrived at the scene. Selection against excessively aggressive parasites that would kill off the host ensembles of genetic elements would lead to early evolution of temperate virus-like agents and primitive defense mechanisms, possibly, based on the RNA interference principle. The emergence of the eukaryotic cell is construed as the second melting pot of virus evolution from which the major groups of eukaryotic viruses originated as a result of extensive recombination of genes from various bacteriophages, archaeal viruses, plasmids, and the evolving eukaryotic genomes. Again, this vision is predicated on a specific model of the emergence of eukaryotic cell under which archaeo-bacterial symbiosis was the starting point of eukaryogenesis, a scenario that appears to be best compatible with the data. Conclusion The existence of several genes that are central to virus replication and structure, are shared by a broad variety of viruses but are missing from cellular genomes (virus hallmark genes suggests the model of an ancient virus world, a flow of virus-specific genes that went uninterrupted from the precellular stage of life's evolution to this day. This concept is tightly linked to two key conjectures on evolution of cells: existence of a complex, precellular, compartmentalized but extensively mixing and recombining pool of genes, and origin of the eukaryotic cell by archaeo-bacterial fusion. The virus world concept and these models of major transitions in the evolution of cells provide complementary pieces of an emerging coherent picture of life's history. Reviewers W. Ford Doolittle, J. Peter Gogarten, and Arcady Mushegian.

  17. Reprogrammed pluripotent stem cells from somatic cells.

    Science.gov (United States)

    Kim, Jong Soo; Choi, Hyun Woo; Choi, Sol; Do, Jeong Tae

    2011-06-01

    Pluripotent stem cells, such as embryonic stem (ES) cells, can differentiate into all cell types. So, these cells can be a biological resource for regenerative medicine. However, ES cells known as standard pluripotent cells have problem to be used for cell therapy because of ethical issue of the origin and immune response on the graft. Hence, recently reprogrammed pluripotent cells have been suggested as an alternative source for regenerative medicine. Somatic cells can acquire the ES cell-like pluripotency by transferring somatic cell nuclei into oocytes, by cell fusion with pluripotent cells. Retroviral-mediated introduction of four factors, Oct4, Sox2, Klf4 and c-Myc can successfully reprogram somatic cells into ES cell-like pluripotent stem cells, known as induced pluripotent stem (iPS) cells. These cells closely resemble ES cells in gene expression pattern, cell biologic and phenotypic characteristics. However, to reach the eventual goal of clinical application, it is necessary to overcome the major drawbacks such as low reprogramming efficiency and genomic alterations due to viral integration. In this review, we discuss the current reprogramming techniques and mechanisms of nuclear reprogramming induced by transcription factor transduction. PMID:24298328

  18. Ghost cell lesions

    Directory of Open Access Journals (Sweden)

    E Rajesh

    2015-01-01

    Full Text Available Ghost cells have been a controversy for a long time. Ghost cell is a swollen/enlarged epithelial cell with eosnophilic cytoplasm, but without a nucleus. In routine H and E staining these cells give a shadowy appearance. Hence these cells are also called as shadow cells or translucent cells. The appearance of these cells varies from lesion to lesion involving odontogenic and nonodontogenic lesions. This article review about the origin, nature and significance of ghost cells in different neoplasms.

  19. Incorporating Cancer Stem Cells in Radiation Therapy Treatment Response Modeling and the Implication in Glioblastoma Multiforme Treatment Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Victoria Y.; Nguyen, Dan; Pajonk, Frank; Kupelian, Patrick; Kaprealian, Tania; Selch, Michael; Low, Daniel A.; Sheng, Ke, E-mail: ksheng@mednet.ucla.edu

    2015-03-15

    Purpose: To perform a preliminary exploration with a simplistic mathematical cancer stem cell (CSC) interaction model to determine whether the tumor-intrinsic heterogeneity and dynamic equilibrium between CSCs and differentiated cancer cells (DCCs) can better explain radiation therapy treatment response with a dual-compartment linear-quadratic (DLQ) model. Methods and Materials: The radiosensitivity parameters of CSCs and DCCs for cancer cell lines including glioblastoma multiforme (GBM), non–small cell lung cancer, melanoma, osteosarcoma, and prostate, cervical, and breast cancer were determined by performing robust least-square fitting using the DLQ model on published clonogenic survival data. Fitting performance was compared with the single-compartment LQ (SLQ) and universal survival curve models. The fitting results were then used in an ordinary differential equation describing the kinetics of DCCs and CSCs in response to 2- to 14.3-Gy fractionated treatments. The total dose to achieve tumor control and the fraction size that achieved the least normal biological equivalent dose were calculated. Results: Smaller cell survival fitting errors were observed using DLQ, with the exception of melanoma, which had a low α/β = 0.16 in SLQ. Ordinary differential equation simulation indicated lower normal tissue biological equivalent dose to achieve the same tumor control with a hypofractionated approach for 4 cell lines for the DLQ model, in contrast to SLQ, which favored 2 Gy per fraction for all cells except melanoma. The DLQ model indicated greater tumor radioresistance than SLQ, but the radioresistance was overcome by hypofractionation, other than the GBM cells, which responded poorly to all fractionations. Conclusion: The distinct radiosensitivity and dynamics between CSCs and DCCs in radiation therapy response could perhaps be one possible explanation for the heterogeneous intertumor response to hypofractionation and in some cases superior outcome from

  20. Gold electrode modified with a self-assembled glucose oxidase and 2,6-pyridinedicarboxylic acid as novel glucose bioanode for biofuel cells

    Science.gov (United States)

    Ammam, Malika; Fransaer, Jan

    2014-07-01

    In this study, we have constructed a gold electrode modified with (3-aminopropyl)trimethoxysilane/2,6-pyridinedicarboxylic acid/glucose oxidase (abbreviated as, Au/ATS/PDA/GOx) by sequential chemical adsorption. Au/ATS/PDA/GOx electrode was characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Electrochemical Impedance Spectroscopy (EIS). The data from FT-IR illustrated deposition of ATS, PDA and GOx on the surface of gold electrode. The latter has been confirmed by EIS which showed that the electron transfer resistance of the electrode increases after adsorption of each supplementary layer. Linear sweep voltammetry (LSV) in phosphate buffer solution containing 5 mM glucose displayed that compared to Au/ATS/GOx, oxidation of glucose at Au/ATS/PDA/GOx electrode starts 461 mV earlier. This gain in potential is attributed to presence of PDA in the constructed Au/ATS/PDA/GOx electrode, which plays some sort of electron mediator for glucose oxidation. The Au/ATS/PDA/GOx electrode was stabilized by an outer layer of polystyrene sulfonate (PSS) and was connected to a Pt electrode as cathode and the non-compartmentalized cell was studied under air in phosphate buffer solution pH 7.4 containing 10 mM glucose. Under these conditions, the maximum power density reaches 0.25 μW mm-2 (25 μW cm-2) for the deposited GOx layer that has an estimated surface coverage of ∼70% of a monolayer.

  1. Murine Mueller cells are progenitor cells for neuronal cells and fibrous tissue cells

    International Nuclear Information System (INIS)

    Mammalian Mueller cells have been reported to possess retinal progenitor cell properties and generate new neurons after injury. This study investigates murine Mueller cells under in vitro conditions for their capability of dedifferentiation into retinal progenitor cells. Mueller cells were isolated from mouse retina, and proliferating cells were expanded in serum-containing medium. For dedifferentiation, the cultured cells were transferred to serum-replacement medium (SRM) at different points in time after their isolation. Interestingly, early cell passages produced fibrous tissue in which extracellular matrix proteins and connective tissue markers were differentially expressed. In contrast, aged Mueller cell cultures formed neurospheres in SRM that are characteristic for neuronal progenitor cells. These neurospheres differentiated into neuron-like cells after cultivation on laminin/ornithine cell culture substrate. Here, we report for the first time that murine Mueller cells can be progenitors for both, fibrous tissue cells and neuronal cells, depending on the age of the cell culture

  2. Sickle Cell Information Center

    Science.gov (United States)

    ... Around the Web Google Custom Search – sickle cell Sickle Cell Anemia - In-Depth Report - NY Times Health January 18, 1970 Sickle cell disease (also called sickle cell anemia) is an inherited blood disorder that affects red ...

  3. Electrorefining cell evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, M.C.; Thomas, R.L. (ed.)

    1989-04-14

    Operational characteristics of the LANL electrorefining cell, a modified LANL electrorefining cell, and an advanced electrorefining cell (known as the CRAC cell) were determined. Average process yields achieved were: 75% for the LANL cell, 82% for the modified LANL cell, and 86% for the CRAC cell. All product metal from the LANL and modified LANL cells was within foundry specifications. Metal from one run in the CRAC cell exceeded foundry specifications for tantalum. The LANL and modified LANL cells were simple in design and operation, but product separation was more labor intensive than with the CRAC cell. The CRAC cell was more complicated in design but remained relatively simple in operation. A decision analysis concluded that the modified LANL cell was the preferred cell. It was recommended that the modified LANL cell be implemented by the Plutonium Recovery Project at Rocky Flats and that development of the CRAC cell continue. 8 refs., 22 figs., 12 tabs.

  4. What are Stem Cells?

    OpenAIRE

    Ahmadshah Farhat; Ashraf Mohammadzadeh; M. Rezaie

    2014-01-01

      Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem ...

  5. Pluripotent stem cell lines

    OpenAIRE

    Yu, Junying; Thomson, James A.

    2008-01-01

    The derivation of human embryonic stem cells 10 years ago ignited an explosion of public interest in stem cells, yet this achievement depended on prior decades of research on mouse embryonic carcinoma cells and embryonic stem cells. In turn, the recent derivation of mouse and human induced pluripotent stem cells depended on the prior studies on mouse and human embryonic stem cells. Both human embryonic stem cells and induced pluripotent stem cells can self-renew indefinitely in vitro while ma...

  6. Discrimination of intra- and extracellular 23Na + signals in yeast cell suspensions using longitudinal magnetic resonance relaxography

    Science.gov (United States)

    Zhang, Yajie; Poirer-Quinot, Marie; Springer, Charles S.; Balschi, James A.

    2010-07-01

    This study tested the ability of MR relaxography (MRR) to discriminate intra- (Nai+) and extracellular (Nae+)23Na + signals using their longitudinal relaxation time constant ( T1) values. Na +-loaded yeast cell ( Saccharomyces cerevisiae) suspensions were investigated. Two types of compartmental 23Na +T1 differences were examined: a selective Nae+T1 decrease induced by an extracellular relaxation reagent (RR e), GdDOTP 5-; and, an intrinsic T1 difference. Parallel studies using the established method of 23Na MRS with an extracellular shift reagent (SR e), TmDOTP 5-, were used to validate the MRR measurements. With 12.8 mM RR e, the 23Nae+T1 was 2.4 ms and the 23Nai+T1 was 9.5 ms (9.4T, 24 °C). The Na + amounts and spontaneous efflux rate constants were found to be identical within experimental error whether measured by MRR/RR e or by MRS/SR e. Without RR e, the Na +-loaded yeast cell suspension 23Na MR signal exhibited two T1 values, 9.1 (±0.3) ms and 32.7 (±2.3) ms, assigned to 23Nai+ and 23Nae+, respectively. The Nai+ content measured was lower, 0.88 (±0.06); while Nae+ was higher, 1.43 (±0.12) compared with MRS/SR e measures on the same samples. However, the measured efflux rate constant was identical. T1 MRR potentially may be used for Nai+ determination in vivo and Na + flux measurements; with RR e for animal studies and without RR e for humans.

  7. DNA-cell conjugates

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  8. Molecular Mechanisms of Cell-cell Recognition

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-Huai

    2004-01-01

    Cell-cell recognition is the key for multicellular organisms to survive. This recognition critically depends on protein-protein interactions from opposing cell surfaces. Recent structural investigations reveal unique features of these cell surface receptors and how they interact. These interactions are specific, but usually relatively weak, with more hydrophilic forces involved in binding. The receptors appear to have specialized ways to present their key interacting elements for ligand-binding from the cell surface. Cell-cell contacts are multivalent. A large group of cell surface molecules are engaged in interactions. Characteristic weak interactions make possible for each individual molecule pair within the group to constantly associate-dissociate-reassociate, such that the cell-cell recognition becomes a dynamic process. The immunological synapse is a good example for immune receptors to be orchestrated in performing immunological function in a collective fashion.

  9. nduced pluripotent stem cells and cell therapy

    Directory of Open Access Journals (Sweden)

    Banu İskender

    2013-12-01

    Full Text Available Human embryonic stem cells are derived from the inner cell mass of a blastocyst-stage embryo. They hold a huge promise for cell therapy with their self-renewing ability and pluripotency, which is known as the potential to differentiate into all cell types originating from three embryonic germ layers. However, their unique pluripotent feature could not be utilised for therapeutic purposes due to the ethical and legal problems during derivation. Recently, it was shown that the cells from adult tissues could be reverted into embryonic state, thereby restoring their pluripotent feature. This has strenghtened the possiblity of directed differentition of the reprogrammed somatic cells into the desired cell types in vitro and their use in regenerative medicine. Although these cells were termed as induced pluripotent cells, the mechanism of pluripotency has yet to be understood. Still, induced pluripotent stem cell technology is considered to be significant by proposing novel approaches in disease modelling, drug screening and cell therapy. Besides their self-renewing ability and their potential to differentiate into all cell types in a human body, they arouse a great interest in scientific world by being far from the ethical concerns regarding their embryonic counterparts and their unique feature of being patient-specific in prospective cell therapies. In this review, induced pluripotent stem cell technology and its role in cell-based therapies from past to present will be discussed. J Clin Exp Invest 2013; 4 (4: 550-561

  10. Modeling cell-in-cell structure into its biological significance

    OpenAIRE

    He, M-f; S. Wang; Wang, Y.; Wang, X-N.

    2013-01-01

    Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ‘entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintainin...

  11. Monitoring cell growth.

    Science.gov (United States)

    Strober, W

    2001-05-01

    This appendix provides two protocols for monitoring cell growth. Counting cells using a hemacytometer is tedious but it allows one to effectively distinguish live cells from dead cells (using Trypan Blue exclusion). In addition, this procedure is less subject to errors due to cell clumping or heterogeneity of cell size. The use of an electronic cell counter is quicker and easier than counting cells using a hemacytometer. However, an electronic cell counter as currently constructed does not distinguish live from dead cells in a reliable fashion and is subject to error due to the presence of cell clumps. Overall, the electronic cell counter is best reserved for repetitive and rapid counting of fresh peripheral blood cells and should be used with caution when counting cell populations derived from tissues. PMID:18432653

  12. Comparison of the contributions of the nuclear and cytoplasmic compartments to global gene expression in human cells

    Directory of Open Access Journals (Sweden)

    Lynch Ronald M

    2007-09-01

    Full Text Available Abstract Background In the most general sense, studies involving global analysis of gene expression aim to provide a comprehensive catalog of the components involved in the production of recognizable cellular phenotypes. These studies are often limited by the available technologies. One technology, based on microarrays, categorizes gene expression in terms of the abundance of RNA transcripts, and typically employs RNA prepared from whole cells, where cytoplasmic RNA predominates. Results Using microarrays comprising oligonucleotide probes that represent either protein-coding transcripts or microRNAs (miRNA, we have studied global transcript accumulation patterns for the HepG2 (human hepatoma cell line. Through subdividing the total pool of RNA transcripts into samples from nuclei, the cytoplasm, and whole cells, we determined the degree of correlation of these patterns across these different subcellular locations. The transcript and miRNA abundance patterns for the three RNA fractions were largely similar, but with some exceptions: nuclear RNA samples were enriched with respect to the cytoplasm in transcripts encoding proteins associated with specific nuclear functions, such as the cell cycle, mitosis, and transcription. The cytoplasmic RNA fraction also was enriched, when compared to the nucleus, in transcripts for proteins related to specific nuclear functions, including the cell cycle, DNA replication, and DNA repair. Some transcripts related to the ubiquitin cycle, and transcripts for various membrane proteins were sorted into either the nuclear or cytoplasmic fractions. Conclusion Enrichment or compartmentalization of cell cycle and ubiquitin cycle transcripts within the nucleus may be related to the regulation of their expression, by preventing their translation to proteins. In this way, these cellular functions may be tightly controlled by regulating the release of mRNA from the nucleus and thereby the expression of key rate limiting

  13. Automated Cell-Cutting for Cell Cloning

    Science.gov (United States)

    Ichikawa, Akihiko; Tanikawa, Tamio; Matsukawa, Kazutsugu; Takahashi, Seiya; Ohba, Kohtaro

    We develop an automated cell-cutting technique for cell cloning. Animal cells softened by the cytochalasin treatment are injected into a microfluidic chip. The microfluidic chip contains two orthogonal channels: one microchannel is wide, used to transport cells, and generates the cutting flow; the other is thin and used for aspiration, fixing, and stretching of the cell. The injected cell is aspirated and stretched in the thin microchannel. Simultaneously, the volumes of the cell before and after aspiration are calculated; the volumes are used to calculate the fluid flow required to aspirate half the volume of the cell into the thin microchannel. Finally, we apply a high-speed flow in the orthogonal microchannel to bisect the cell. This paper reports the cutting process, the cutting system, and the results of the experiment.

  14. Inactivation of agmatinase expressed in vegetative cells alters arginine catabolism and prevents diazotrophic growth in the heterocyst-forming cyanobacterium Anabaena.

    Science.gov (United States)

    Burnat, Mireia; Flores, Enrique

    2014-10-01

    Arginine decarboxylase produces agmatine, and arginase and agmatinase are ureohydrolases that catalyze the production of ornithine and putrescine from arginine and agmatine, respectively, releasing urea. In the genome of the filamentous, heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120, ORF alr2310 putatively encodes an ureohydrolase. Cells of Anabaena supplemented with [(14) C]arginine took up and catabolized this amino acid generating a set of labeled amino acids that included ornithine, proline, and glutamate. In an alr2310 deletion mutant, an agmatine spot appeared and labeled glutamate increased with respect to the wild type, suggesting that Alr2310 is an agmatinase rather than an arginase. As determined in cell-free extracts, agmatinase activity could be detected in the wild type but not in the mutant. Thus, alr2310 is the Anabaena speB gene encoding agmatinase. The ∆alr2310 mutant accumulated large amounts of cyanophycin granule polypeptide, lacked nitrogenase activity, and did not grow diazotrophically. Growth tests in solid media showed that agmatine is inhibitory for Anabaena, especially under diazotrophic conditions, suggesting that growth of the mutant is inhibited by non-metabolized agmatine. Measurements of incorporation of radioactivity from [(14) C]leucine into macromolecules showed, however, a limited inhibition of protein synthesis in the ∆alr2310 mutant. Analysis of an Anabaena strain producing an Alr2310-GFP (green fluorescent protein) fusion showed expression in vegetative cells but much less in heterocysts, implying compartmentalization of the arginine decarboxylation pathway in the diazotrophic filaments of this heterocyst-forming cyanobacterium.

  15. Sickle Cell Anemia

    Science.gov (United States)

    Sickle cell anemia is a disease in which your body produces abnormally shaped red blood cells. The cells are shaped like a crescent or sickle. They ... last as long as normal, round red blood cells. This leads to anemia. The sickle cells also ...

  16. CELL RESEARCH

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    REVIEWSInducible resistance to Fas-mediated apoptosis in B cells…………………………………ROTHSTEIN Thomas L (245)Executionary pathway for apoptosis: lessons from mutant mice………………………………………WOO Minna, Razqallah Hakem, Tak W Mak (267)The SHP-2 tyrosine phosphatase: Signaling mechanisms and biological functions…………………………………QU Cheng Kui (279)REGULAR ARTICLESTemperature dependent expression of cdc2 and cyclin B1 in spermatogenic cells during spermatogenesis…………………………KONG Wei Hua, Zheng GU, Jining LU, Jiake TSO (289)Transgenic mice overexpressing γ-aminobutyric acid transporter subtype I develop obesity…………………………………MA Ying Hua, Jia Hua HU, Xiao Gang ZHOU, Ruo Wang ZENG, Zhen Tong MEI, Jian FEI, Li He GUO (303)Genetic aberration in primary hepatocellular carcinoma: correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23………………………………………WANG Gang, Chang Hui HUANG, Yan ZHAO, Ling CAI, Ying WANG, Shi Jin XIU, Zheng Wen JIANG, Shuang YANG, Xin Tai ZHAO, Wei HUANG, Jian Ren GU (311)Identification and genetic mapping of four novel genes that regulate leaf deve- lopment in Arabidopsis………………………………………………SUN Yue, Wei ZHANG, Feng Ling LI, Ying Li GUO, Tian Lei LIU, Hai HUANG (325)NOTICE FOR CONTRIBUTORS…………………………………(337)CONTENTS of Vol. 10, 2000…………………………………………………(338)

  17. Cell Membrane Softening in Cancer Cells

    Science.gov (United States)

    Schmidt, Sebastian; Händel, Chris; Käs, Josef

    Biomechanical properties are useful characteristics and regulators of the cell's state. Current research connects mechanical properties of the cytoskeleton to many cellular processes but does not investigate the biomechanics of the plasma membrane. We evaluated thermal fluctuations of giant plasma membrane vesicles, directly derived from the plasma membranes of primary breast and cervical cells and observed a lowered rigidity in the plasma membrane of malignant cells compared to non-malignant cells. To investigate the specific role of membrane rigidity changes, we treated two cell lines with the Acetyl-CoA carboxylase inhibitor Soraphen A. It changed the lipidome of cells and drastically increased membrane stiffness by up regulating short chained membrane lipids. These altered cells had a decreased motility in Boyden chamber assays. Our results indicate that the thermal fluctuations of the membrane, which are much smaller than the fluctuations driven by the cytoskeleton, can be modulated by the cell and have an impact on adhesion and motility.

  18. Sickle cell anemia - resources

    Science.gov (United States)

    Resources - sickle cell anemia ... The following organizations are good resources for information on sickle cell anemia : American Sickle Cell Anemia Association -- www.ascaa.org National Heart, Blood, and Lung Institute -- www. ...

  19. Sickle Cell Disease

    Science.gov (United States)

    ... in Sickle Cell Disease New supplement from the American Journal of Preventive Medicine describes the state of sickle cell disease related care in the United States. Read Supplement » ... are affected by sickle cell disease. More WEBINAR ...

  20. Sickle Cell Disease

    Science.gov (United States)

    ... from the NHLBI on Twitter. What Is Sickle Cell Disease? Español The term sickle cell disease (SCD) ... common forms of SCD. Some Forms of Sickle Cell Disease Hemoglobin SS Hemoglobin SC Hemoglobin Sβ 0 thalassemia ...

  1. Squamous cell skin cancer

    Science.gov (United States)

    ... earliest form of squamous cell cancer is called Bowen disease (or squamous cell carcinoma in situ). This type ... cancer; Squamous cell carcinoma of the skin Images Bowen's disease on the hand Keratoacanthoma Keratoacanthoma Skin cancer, squamous ...

  2. Lung cancer - small cell

    Science.gov (United States)

    Cancer - lung - small cell; Small cell lung cancer; SCLC ... About 15% of all lung cancer cases are SCLC. Small cell lung cancer is slightly more common in men than women. Almost all cases of SCLC ...

  3. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  4. Lung cancer - small cell

    Science.gov (United States)

    Cancer - lung - small cell; Small cell lung cancer; SCLC ... About 15% of all lung cancer cases are SCLC. Small cell lung cancer is slightly more common in men than women. Almost all cases of SCLC are ...

  5. Basal Cell Carcinoma (BCC)

    Science.gov (United States)

    ... epithelioma, is the most common form of skin cancer. Basal cell carcinoma usually occurs on sun-damaged skin, especially ... other health issues. Infiltrating or morpheaform basal cell carcinomas: Infiltrating basal cell carcinomas can be more aggressive and locally destructive ...

  6. Immobilization of cells via activated cell walls

    Energy Technology Data Exchange (ETDEWEB)

    Markt, M.; Kas, J.; Valentova, O.; Demnerova, K.; Vodrazka, Z.

    1986-10-01

    Cell walls of Saccharomyces cerevisiae and S. uvarum were activated by periodate oxidation of vicinal diol groups in cell wall polysaccharides. The aldehyde groups thus generated allow the yeast cells to be covalently bound to modified bead cellulose or macroporous glycidyl methacrylate supports, or to enzymes such as glucose oxidase and catalase. 6 references.

  7. Visualizing the actin cytoskeleton in living plant cells using a photo-convertible mEos::FABD-mTn fluorescent fusion protein

    Directory of Open Access Journals (Sweden)

    Bewley J Derek

    2008-09-01

    Full Text Available Abstract Background The actin cytoskeleton responds quickly to diverse stimuli and plays numerous roles in cellular signalling, organelle motility and subcellular compartmentation during plant growth and development. Molecular and cell biological tools that can facilitate visualization of actin organization and dynamics in a minimally invasive manner are essential for understanding this fundamental component of the living cell. Results A novel, monomeric (m Eos-fluorescent protein derived from the coral Lobophyllia hemprichii was assessed for its green to red photo-convertibility in plant cells by creating mEosFP-cytosolic. mEosFP was fused to the F-(filamentous-Actin Binding Domain of the mammalian Talin gene to create mEosFP::FABDmTalin. Photo-conversion, visualization and colour quantification protocols were developed for EosFP targeted to the F-actin cytoskeleton. Rapid photo-conversion in the entire cell or in a region of interest was easily achieved upon illumination with an approximately 400 nm wavelength light beam using an epi-fluorescent microscope. Dual color imaging after photo-conversion was carried out using a confocal laser-scanning microscope. Time-lapse imaging revealed that although photo-conversion of single mEosFP molecules can be rapid in terms of live-cell imaging it involves a progressive enrichment of red fluorescent molecules over green species. The fluorescence of photo-converted cells thus progresses through intermediate shades ranging from green to red. The time taken for complete conversion to red fluorescence depends on protein expression level within a cell and the quality of the focusing lens used to deliver the illuminating beam. Three easily applicable methods for obtaining information on fluorescent intensity and colour are provided as a means of ensuring experimental repeatability and data quantification, when using mEosFP and similar photo-convertible proteins. Conclusion The mEosFP::FABD-mTn probe retains

  8. Cancer cells metabolically "fertilize" the tumor microenvironment with hydrogen peroxide, driving the Warburg effect: implications for PET imaging of human tumors.

    Science.gov (United States)

    Martinez-Outschoorn, Ubaldo E; Lin, Zhao; Trimmer, Casey; Flomenberg, Neal; Wang, Chenguang; Pavlides, Stephanos; Pestell, Richard G; Howell, Anthony; Sotgia, Federica; Lisanti, Michael P

    2011-08-01

    Previously, we proposed that cancer cells behave as metabolic parasites, as they use targeted oxidative stress as a "weapon" to extract recycled nutrients from adjacent stromal cells. Oxidative stress in cancer-associated fibroblasts triggers autophagy and  mitophagy, resulting in compartmentalized cellular catabolism, loss of mitochondrial function, and the onset of aerobic glycolysis, in the tumor stroma. As such, cancer-associated fibroblasts produce high-energy nutrients (such as lactate and ketones) that fuel mitochondrial biogenesis, and oxidative metabolism in cancer cells. We have termed this new energy-transfer mechanism the "reverse Warburg effect." To further test the validity of this hypothesis, here we used an in vitro MCF7-fibroblast co-culture system, and quantitatively measured a variety of metabolic parameters by FACS analysis (analogous to laser-capture micro-dissection).  Mitochondrial activity, glucose uptake, and ROS production were measured with highly-sensitive fluorescent probes (MitoTracker, NBD-2-deoxy-glucose, and DCF-DA). Interestingly, using this approach, we directly show that cancer cells initially secrete hydrogen peroxide that then triggers oxidative stress in neighboring fibroblasts. Thus, oxidative stress is contagious (spreads like a virus) and is propagated laterally and vectorially from cancer cells to adjacent fibroblasts. Experimentally, we show that oxidative stress in cancer-associated fibroblasts quantitatively reduces mitochondrial activity, and increases glucose uptake, as the fibroblasts become more dependent on aerobic glycolysis.  Conversely, co-cultured cancer cells show significant increases in mitochondrial activity, and corresponding reductions in both glucose uptake and GLUT1 expression. Pre-treatment of co-cultures with extracellular catalase (an anti-oxidant enzyme that detoxifies hydrogen peroxide) blocks the onset of oxidative stress, and potently induces the death of cancer cells, likely via starvation

  9. Snail modulates cell metabolism in MDCK cells

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  10. Cell aggregation and sedimentation.

    Science.gov (United States)

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  11. Artificial Stem Cell Niches

    OpenAIRE

    Lutolf, Matthias P.; Blau, Helen M.

    2009-01-01

    Stem cells are characterized by their dual ability to reproduce themselves (self-renew) and specialize (differentiate), yielding a plethora of daughter cells that maintain and regenerate tissues. In contrast to their embryonic counterparts, adult stem cells retain their unique functions only if they are in intimate contact with an instructive microenvironment, termed stem cell niche. In these niches, stem cells integrate a complex array of molecular signals that, in concert with induced cell-...

  12. Fish Stem Cell Cultures

    OpenAIRE

    Ni Hong, Zhendong Li, Yunhan Hong

    2011-01-01

    Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES) cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is th...

  13. Stem Cell Separation Technologies

    OpenAIRE

    Zhu, Beili; Murthy, Shashi K

    2013-01-01

    Stem cell therapy and translational stem cell research require large-scale supply of stem cells at high purity and viability, thus leading to the development of stem cell separation technologies. This review covers key technologies being applied to stem cell separation, and also highlights exciting new approaches in this field. First, we will cover conventional separation methods that are commercially available and have been widely adapted. These methods include Fluorescence-activated cell so...

  14. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  15. Collective motor dynamics in membrane transport in vitro

    NARCIS (Netherlands)

    Shaklee, Paige Marie

    2009-01-01

    Key cellular processes such as cell division, internal cellular organization, membrane compartmentalization and intracellular transport rely on motor proteins. Motor proteins, ATP-based mechanoenzymes, actively transport cargo throughout the cell by walking on cytoskeletal filaments. Motors have bee

  16. Detergent resistant membrane fractions are involved in calcium signaling in Müller glial cells of retina.

    Science.gov (United States)

    Krishnan, Gopinath; Chatterjee, Nivedita

    2013-08-01

    Compartmentalization of the plasma membrane into lipid microdomains promotes efficient cellular processes by increasing local molecular concentrations. Calcium signaling, either as transients or propagating waves require integration of complex macromolecular machinery. Calcium waves represent a form of intercellular signaling in the central nervous system and the retina. We hypothesized that the mechanism for calcium waves would require effector proteins to aggregate at the plasma membrane in lipid microdomains. The current study shows that in Müller glia of the retina, proteins involved in calcium signaling aggregate in detergent resistant membranes identifying rafts and respond by redistributing on stimulation. We have investigated Purinoreceptor-1 (P2Y1), Ryanodine receptor (RyR), and Phospholipase C (PLC-β1). P2Y1, RyR and PLC-β1, redistribute from caveolin-1 and flotillin-1 positive fractions on stimulation with the agonists, ATP, 2MeS-ATP and Thapsigargin, an inhibitor of sarcoplasmic-endoplasmic reticulum Ca-ATPase (SERCA). Redistribution is absent on treatment with cyclopiazonic acid, another SERCA inhibitor. Disruption of rafts by removing cholesterol cause proteins involved in this machinery to redistribute and change agonist-induced calcium signaling. Cholesterol depletion from raft lead to increase in time to peak of calcium levels in agonist-evoked calcium signals in all instances, as seen by live imaging. This study emphasizes the necessity of a sub-population of proteins to cluster in specialized lipid domains. The requirement for such an organization at the raft-like microdomains may have implications on intercellular communication in the retina. Such concerted interaction at the rafts can regulate calcium dynamics and could add another layer of complexity to calcium signaling in cells.

  17. Polymer-based protein engineering grown ferrocene-containing redox polymers improve current generation in an enzymatic biofuel cell.

    Science.gov (United States)

    Campbell, Alan S; Murata, Hironobu; Carmali, Sheiliza; Matyjaszewski, Krzysztof; Islam, Mohammad F; Russell, Alan J

    2016-12-15

    Enzymatic biofuel cells (EBFCs) are capable of generating electricity from physiologically present fuels making them promising power sources for the future of implantable devices. The potential application of such systems is limited, however, by inefficient current generation. Polymer-based protein engineering (PBPE) offers a unique method to tailor enzyme function through tunable modification of the enzyme surface with functional polymers. In this study, we report on the modification of glucose oxidase (GOX) with ferrocene-containing redox polymers to increase current generation efficiency in an enzyme-modified anode. Poly(N-(3-dimethyl(ferrocenyl)methylammonium bromide)propyl acrylamide) (pFcAc) was grown from covalently attached, water-soluble initiator molecules on the surface of GOX in a "grafting-from" approach using atom transfer radical polymerization (ATRP). The covalently-coupled ferrocene-containing polymers on the enzyme surface promoted the effective "wiring" of the GOX active site to an external electrode. The resulting GOX-pFcAc conjugates generated over an order of magnitude increase in current generation efficiency and a 4-fold increase in maximum EBFC power density (≈1.7µWcm(-2)) with similar open circuit voltage (0.27V) compared to native GOX when physically adsorbed onto paddle-shaped electrodes made up of electrospun polyacrylonitrile fibers coated with gold nanoparticles and multi-wall carbon nanotubes. The formation of electroactive enzyme-redox polymer conjugates using PBPE represents a powerful new tool for the improvement of mediated enzyme-based bioelectronics without the need for free redox mediators or anode/cathode compartmentalization. PMID:27424262

  18. Polymer-based protein engineering grown ferrocene-containing redox polymers improve current generation in an enzymatic biofuel cell.

    Science.gov (United States)

    Campbell, Alan S; Murata, Hironobu; Carmali, Sheiliza; Matyjaszewski, Krzysztof; Islam, Mohammad F; Russell, Alan J

    2016-12-15

    Enzymatic biofuel cells (EBFCs) are capable of generating electricity from physiologically present fuels making them promising power sources for the future of implantable devices. The potential application of such systems is limited, however, by inefficient current generation. Polymer-based protein engineering (PBPE) offers a unique method to tailor enzyme function through tunable modification of the enzyme surface with functional polymers. In this study, we report on the modification of glucose oxidase (GOX) with ferrocene-containing redox polymers to increase current generation efficiency in an enzyme-modified anode. Poly(N-(3-dimethyl(ferrocenyl)methylammonium bromide)propyl acrylamide) (pFcAc) was grown from covalently attached, water-soluble initiator molecules on the surface of GOX in a "grafting-from" approach using atom transfer radical polymerization (ATRP). The covalently-coupled ferrocene-containing polymers on the enzyme surface promoted the effective "wiring" of the GOX active site to an external electrode. The resulting GOX-pFcAc conjugates generated over an order of magnitude increase in current generation efficiency and a 4-fold increase in maximum EBFC power density (≈1.7µWcm(-2)) with similar open circuit voltage (0.27V) compared to native GOX when physically adsorbed onto paddle-shaped electrodes made up of electrospun polyacrylonitrile fibers coated with gold nanoparticles and multi-wall carbon nanotubes. The formation of electroactive enzyme-redox polymer conjugates using PBPE represents a powerful new tool for the improvement of mediated enzyme-based bioelectronics without the need for free redox mediators or anode/cathode compartmentalization.

  19. Fusion with stem cell makes the hepatocellular carcinoma cells similar to liver tumor-initiating cells

    OpenAIRE

    Wang, Ran; Chen, Shuxun; Li, Changxian; Ng, Kevin Tak Pan; Kong, Chi-Wing; Cheng, Jinping; Cheng, Shuk Han; Li, Ronald A.; Lo, Chung Mau; Man, Kwan; Sun, Dong

    2016-01-01

    Background Cell fusion is a fast and highly efficient technique for cells to acquire new properties. The fusion of somatic cells with stem cells can reprogram somatic cells to a pluripotent state. Our research on the fusion of stem cells and cancer cells demonstrates that the fused cells can exhibit stemness and cancer cell-like characteristics. Thus, tumor-initiating cell-like cells are generated. Methods We employed laser-induced single-cell fusion technique to fuse the hepatocellular carci...

  20. Cancer stem cell-like cells from a single cell of oral squamous carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Felthaus, O. [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany); Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Ettl, T.; Gosau, M.; Driemel, O. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Brockhoff, G. [Department of Gynecology and Obstetrics, University of Regensburg (Germany); Reck, A. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Zeitler, K. [Institute of Pathology, University of Regensburg (Germany); Hautmann, M. [Department of Radiotherapy, University of Regensburg (Germany); Reichert, T.E. [Department of Oral and Maxillofacial Surgery, University of Regensburg (Germany); Schmalz, G. [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany); Morsczeck, C., E-mail: christian.morsczeck@klinik.uni-regensburg.de [Department of Operative Dentistry and Periodontology, University of Regensburg (Germany)

    2011-04-01

    Research highlights: {yields} Four oral squamous cancer cell lines (OSCCL) were analyzed for cancer stem cells (CSCs). {yields} Single cell derived colonies of OSCCL express CSC-marker CD133 differentially. {yields} Monoclonal cell lines showed reduced sensitivity for Paclitaxel. {yields} In situ CD133{sup +} cells are slow cycling (Ki67-) indicating a reduced drug sensitivity. {yields} CD133{sup +} and CSC-like cells can be obtained from single colony forming cells of OSCCL. -- Abstract: Resistance of oral squamous cell carcinomas (OSCC) to conventional chemotherapy or radiation therapy might be due to cancer stem cells (CSCs). The development of novel anticancer drugs requires a simple method for the enrichment of CSCs. CSCs can be enriched from OSCC cell lines, for example, after cultivation in serum-free cell culture medium (SFM). In our study, we analyzed four OSCC cell lines for the presence of CSCs. CSC-like cells could not be enriched with SFM. However, cell lines obtained from holoclone colonies showed CSC-like properties such as a reduced rate of cell proliferation and a reduced sensitivity to Paclitaxel in comparison to cells from the parental lineage. Moreover, these cell lines differentially expressed the CSC-marker CD133, which is also upregulated in OSCC tissues. Interestingly, CD133{sup +} cells in OSCC tissues expressed little to no Ki67, the cell proliferation marker that also indicates reduced drug sensitivity. Our study shows a method for the isolation of CSC-like cell lines from OSCC cell lines. These CSC-like cell lines could be new targets for the development of anticancer drugs under in vitro conditions.

  1. Cancer stem cell-like cells from a single cell of oral squamous carcinoma cell lines

    International Nuclear Information System (INIS)

    Research highlights: → Four oral squamous cancer cell lines (OSCCL) were analyzed for cancer stem cells (CSCs). → Single cell derived colonies of OSCCL express CSC-marker CD133 differentially. → Monoclonal cell lines showed reduced sensitivity for Paclitaxel. → In situ CD133+ cells are slow cycling (Ki67-) indicating a reduced drug sensitivity. → CD133+ and CSC-like cells can be obtained from single colony forming cells of OSCCL. -- Abstract: Resistance of oral squamous cell carcinomas (OSCC) to conventional chemotherapy or radiation therapy might be due to cancer stem cells (CSCs). The development of novel anticancer drugs requires a simple method for the enrichment of CSCs. CSCs can be enriched from OSCC cell lines, for example, after cultivation in serum-free cell culture medium (SFM). In our study, we analyzed four OSCC cell lines for the presence of CSCs. CSC-like cells could not be enriched with SFM. However, cell lines obtained from holoclone colonies showed CSC-like properties such as a reduced rate of cell proliferation and a reduced sensitivity to Paclitaxel in comparison to cells from the parental lineage. Moreover, these cell lines differentially expressed the CSC-marker CD133, which is also upregulated in OSCC tissues. Interestingly, CD133+ cells in OSCC tissues expressed little to no Ki67, the cell proliferation marker that also indicates reduced drug sensitivity. Our study shows a method for the isolation of CSC-like cell lines from OSCC cell lines. These CSC-like cell lines could be new targets for the development of anticancer drugs under in vitro conditions.

  2. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Nora [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Vereb, Zoltan; Rajnavoelgyi, Eva [Department of Immunology, Medical and Health Science Centre, University of Debrecen, Debrecen (Hungary); Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Apati, Agota, E-mail: apati@kkk.org.hu [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  3. SMOOTH MUSCLE STEM CELLS

    Science.gov (United States)

    Vascular smooth muscle cells (SMCs) originate from multiple types of progenitor cells. In the embryo, the most well-studied SMC progenitor is the cardiac neural crest stem cell. Smooth muscle differentiation in the neural crest lineage is controlled by a combination of cell intrinsic factors, includ...

  4. Sickle Cell Disease

    Science.gov (United States)

    ... sickle cell disease? Sickle cell disease, also called sickle cell anemia, is a hereditary condition (which means it runs ... or blocks blood and oxygen reaching nearby tissues. Sickle cell disease ... the whites of the eyes) Anemia (the decreased ability of the blood to carry ...

  5. Physiology, morphology and detailed passive models of guinea-pig cerebellar Purkinje cells.

    Science.gov (United States)

    Rapp, M; Segev, I; Yarom, Y

    1994-01-01

    1. Purkinje cells (PCs) from guinea-pig cerebellar slices were physiologically characterized using intracellular techniques. Extracellular caesium ions were used to linearize the membrane properties of PCs near the resting potential. Under these conditions the average input resistance, RN, was 29 M omega, the average system time constant, tau 0, was 82 ms and the average cable length, LN, was 0.59. 2. Three PCs were fully reconstructed following physiological measurements and staining with horseradish peroxidase. Assuming that each spine has an area of 1 micron 2 and that the spine density over the spiny dendrites is ten spines per micrometre length, the total membrane area of each PC is approximately 150,000 microns 2, of which approximately 100,000 microns 2 is in the spines. 3. Detailed passive cable and compartmental models were built for each of the three reconstructed PCs. Computational methods were devised to incorporate globally the huge number of spines into these models. In all three cells the models predict that the specific membrane resistivity, Rm, of the soma is much lower than the dendritic Rm (approximately 500 and approximately 100,000 omega cm2 respectively). The specific membrane capacitance, Cm, is estimated to be 1.5-2 muF cm-2 and the specific cytoplasm resistivity, Ri, is 250 omega cm. 4. The average cable length of the dendrites according to the model is 0.13 lambda, suggesting that under caesium conditions PCs are electrically very compact. Brief somatic spikes, however, are expected to attenuate 30-fold when spreading passively into the dendritic terminals. A simulated 200 Hz train of fast, 90 mV somatic spikes produced a smooth 12 mV steady depolarization at the dendritic terminals. 5. A transient synaptic conductance increase, with a 1 nS peak at 0.5 ms and a driving force of 60 mV, is expected to produce approximately 20 mV peak depolarization at the spine head membrane. This EPSP then attenuates between 200- and 900-fold into the soma

  6. When Blood Cells Bend: Understanding Sickle Cell Disease

    Science.gov (United States)

    ... please review our exit disclaimer . Subscribe When Blood Cells Bend Understanding Sickle Cell Disease For people who don’t suspect they ... Cells Bend Wise Choices Links Living with Sickle Cell Disease See a sickle cell disease expert regularly. ...

  7. Ganglion cell like cells, diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Anand Shankar Ammanagi

    2013-01-01

    Full Text Available We report a case of cutaneous swelling found on the left anterior axillary fold of a 41-year-old man. Gross examination of specimen excised from the dermis showed a well-circumscribed nodule histologically composed of spindle cells with interspersed ganglion cell like cells. On hematoxylin and eosine (H and E staining it was diagnosed as ganglioneuroma. Ganglioneuromas are rare, benign, fully differentiated tumors that contain mature schwann cells, ganglion cells, fibrous tissue, and nerve fibers. They are commonly found along the paravertebral sympathetic ganglia and sometimes in the adrenal medulla. However primary cutaneous ganglioneuroma is an extremely rare tumor. Immunohistochemical workup revealed a fibroblastic origin and hence the case was diagnosed as fibromatosis with ganglion cell like fibroblasts. This case report suggests that the features considered diagnostic of ganglioneuromas can occur in other cutaneous lesions and, therefore, this diagnosis cannot be offered only on the basis of H and E.

  8. Cell fusion of bone marrow cells and somatic cell reprogramming by embryonic stem cells

    OpenAIRE

    Bonde, Sabrina; Pedram, Mehrdad; Stultz, Ryan; Zavazava, Nicholas

    2010-01-01

    Bone marrow transplantation is a curative treatment for many diseases, including leukemia, autoimmune diseases, and a number of immunodeficiencies. Recently, it was claimed that bone marrow cells transdifferentiate, a much desired property as bone marrow cells are abundant and therefore could be used in regenerative medicine to treat incurable chronic diseases. Using a Cre/loxP system, we studied cell fusion after bone marrow transplantation. Fused cells were chiefly Gr-1+, a myeloid cell mar...

  9. Hepatic stem cell niches

    OpenAIRE

    Kordes, Claus; Häussinger, Dieter

    2013-01-01

    Stem cell niches are special microenvironments that maintain stem cells and control their behavior to ensure tissue homeostasis and regeneration throughout life. The liver has a high regenerative capacity that involves stem/progenitor cells when the proliferation of hepatocytes is impaired. In recent years progress has been made in the identification of potential hepatic stem cell niches. There is evidence that hepatic progenitor cells can originate from niches in the canals...

  10. Stem Cell Networks

    OpenAIRE

    Werner, Eric

    2016-01-01

    We present a general computational theory of stem cell networks and their developmental dynamics. Stem cell networks are special cases of developmental control networks. Our theory generates a natural classification of all possible stem cell networks based on their network architecture. Each stem cell network has a unique topology and semantics and developmental dynamics that result in distinct phenotypes. We show that the ideal growth dynamics of multicellular systems generated by stem cell ...

  11. Stem cell mechanobiology

    OpenAIRE

    David A. Lee; Knight, Martin M.; Jonathan J Campbell; Bader, Dan L.

    2010-01-01

    Stem cells are undifferentiated cells that are capable of proliferation, self-maintenance and differentiation towards specific cell phenotypes. These processes are controlled by a variety of cues including physicochemical factors associated with the specific mechanical environment in which the cells reside. The control of stem cell biology through mechanical factors remains poorly understood and is the focus of the developing field of mechanobiology. This review provides an insight into the c...

  12. Embryonic Stem Cell Markers

    OpenAIRE

    Lan Ma; Liang Li; Wenxiu Zhao; Xiang Ji; Fangfang Zhang

    2012-01-01

    Embryonic stem cell (ESC) markers are molecules specifically expressed in ES cells. Understanding of the functions of these markers is critical for characterization and elucidation for the mechanism of ESC pluripotent maintenance and self-renewal, therefore helping to accelerate the clinical application of ES cells. Unfortunately, different cell types can share single or sometimes multiple markers; thus the main obstacle in the clinical application of ESC is to purify ES cells from other type...

  13. Limbal stem cell transplantation

    OpenAIRE

    Fernandes Merle; Sangwan Virender; Rao Srinivas; Basti Surendra; Sridhar Mittanamalli; Bansal Aashish; Dua Harminder

    2004-01-01

    The past two decades have witnessed remarkable progress in limbal stem cell transplantation. In addition to harvesting stem cells from a cadaver or a live related donor, it is now possible to cultivate limbal stem cells in vitro and then transplant them onto the recipient bed. A clear understanding of the basic disease pathology and a correct assessment of the extent of stem cell deficiency are essential. A holistic approach towards management of limbal stem cell deficiency is needed. This ...

  14. Intraoperative Stem Cell Therapy

    OpenAIRE

    Coelho, Mónica Beato; Cabral, Joaquim M. S.; Karp, Jeffrey M.

    2012-01-01

    Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the poten...

  15. The leukemic stem cell

    OpenAIRE

    Jordan, Craig T.

    2007-01-01

    Malignant stem cells have recently been described as the source of several types of human cancer. These unique cell types are typically rare and possess properties that are distinct from most other tumor cells. The properties of leukemic stem cells indicate that current chemotherapy drugs will not be effective. The use of current cytotoxic agents is not effective in leukemia because the agents target both the leukemic and normal stem cell populations. Consequently, new strategies are required...

  16. Cancer Stem Cells

    OpenAIRE

    Katarzyna Wieczorek; Jolanta Niewiarowska

    2008-01-01

    Cancer stem cell theory gains increasingly greater significance in the world of medicine. Numerous findings of scientific research in vivo and in vitro indicate that it is the population of undifferentiated, self-renewing cells which is responsible for recurrence of cancer and metastasis. Similarly to normal stem cells, cancer stem cells (CSC) function in the environment of the other cells of the organism, called the niche, where they receive signals for differentiation and proliferation proc...

  17. The cell cycle as a brake for β-cell regeneration from embryonic stem cells

    OpenAIRE

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-01

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle ...

  18. Mechanically facilitated cell-cell electrofusion.

    OpenAIRE

    Jaroszeski, M. J.; Gilbert, R.; Fallon, P.G.; Heller, R

    1994-01-01

    Apparatus and methods were developed to enable mechanically facilitated cell-cell electrofusion to be performed. The apparatus and methods mechanically place cells in contact before fusion. The key component of this fusion system was a newly developed fusion chamber. The chamber was composed of two functionally identical electrodes that were housed in a multi-layer structure. The layers functioned as support for the electrodes. They also allowed adjustment of the distance between opposing ele...

  19. Optimizing stem cell culture.

    Science.gov (United States)

    van der Sanden, Boudewijn; Dhobb, Mehdi; Berger, François; Wion, Didier

    2010-11-01

    Stem cells always balance between self-renewal and differentiation. Hence, stem cell culture parameters are critical and need to be continuously refined according to progress in our stem cell biology understanding and the latest technological developments. In the past few years, major efforts have been made to define more precisely the medium composition in which stem cells grow or differentiate. This led to the progressive replacement of ill-defined additives such as serum or feeder cell layers by recombinant cytokines or growth factors. Another example is the control of the oxygen pressure. For many years cell cultures have been done under atmospheric oxygen pressure which is much higher than the one experienced by stem cells in vivo. A consequence of cell metabolism is that cell culture conditions are constantly changing. Therefore, the development of high sensitive monitoring processes and control algorithms is required for ensuring cell culture medium homeostasis. Stem cells also sense the physical constraints of their microenvironment. Rigidity, stiffness, and geometry of the culture substrate influence stem cell fate. Hence, nanotopography is probably as important as medium formulation in the optimization of stem cell culture conditions. Recent advances include the development of synthetic bioinformative substrates designed at the micro- and nanoscale level. On going research in many different fields including stem cell biology, nanotechnology, and bioengineering suggest that our current way to culture cells in Petri dish or flasks will soon be outdated as flying across the Atlantic Ocean in the Lindbergh's plane. PMID:20803548

  20. Living with Sickle Cell Disease

    Science.gov (United States)

    ... sickle cell disease, go to the Health Topics Sickle Cell Anemia article. Living With and Managing Sickle Cell Disease ( ... the most severe form of sickle cell disease, sickle cell anemia, Tiffany has lived with the symptoms and complications ...

  1. What Causes Sickle Cell Disease?

    Science.gov (United States)

    ... sickle cell disease, go to the Health Topics Sickle Cell Anemia article. Living With and Managing Sickle Cell Disease ( ... the most severe form of sickle cell disease, sickle cell anemia, Tiffany has lived with the symptoms and complications ...

  2. Hyperpolarised Organic Phosphates as NMR Reporters of Compartmental pH

    DEFF Research Database (Denmark)

    Jensen, Pernille Rose; Meier, Sebastian

    2016-01-01

    Organic phosphate metabolites contain functional groups withpKa values near the physiologic pH range, yielding pH-dependet 13C chemical shift changes of adjacent quaternary carbon sites.Whenformed in defined cellular compartmentsfrom exogenoushyperpolarised13Csubstrates,metabolites thuscanyieldlo......Organic phosphate metabolites contain functional groups withpKa values near the physiologic pH range, yielding pH-dependet 13C chemical shift changes of adjacent quaternary carbon sites.Whenformed in defined cellular compartmentsfrom exogenoushyperpolarised13Csubstrates...

  3. CT evaluation of soft tissue and muscle infection and inflammation: A systematic compartmental approach

    Energy Technology Data Exchange (ETDEWEB)

    Beauchamp, N.J. Jr. [Dept. of Radiology, and Radiological Science, The Johns Hopkins Medical Institutions, Baltimore, MD (United States); Scott, W.W. Jr. [Dept. of Radiology, and Radiological Science, The Johns Hopkins Medical Institutions, Baltimore, MD (United States); Gottlieb, L.M. [Dept. of Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD (United States); Fishman, E.K. [Dept. of Surgery, The Johns Hopkins Medical Institutions, Baltimore, MD (United States)

    1995-07-01

    This essay presents a systematic approach to the evaluation of soft tissue and muscle infection by defining the various pathologic processes and then illustrating them through a series of CT studies with corresponding schematic diagrams. The specific processes discussed are cellulitis, lymphangitis/lymphedema, necrotizing fascitis, myositis/myonecrosis, and abscess. Key points in the differential diagnosis of these entities are discussed and illustrated. The clinical management of the specific pathologic processes is also discussed. (orig./MG)

  4. Compartmentalized and signal-selective gap junctional coupling in the hearing cochlea

    OpenAIRE

    Jagger, D J; Forge, A

    2006-01-01

    Gap junctional intercellular communication (GJIC) plays a major role in cochlear function. Recent evidence suggests that connexin 26 (Cx26) and Cx30 are the major constituent proteins of cochlear gap junction channels, possibly in a unique heteromeric configuration. We investigated the functional and structural properties of native cochlear gap junctions in rats, from birth to the onset of hearing [ postnatal day 12 (P12)]. Confocal immunofluorescence revealed increasing Cx26 and Cx30 express...

  5. Application of compartmental metabolic models for determination of retention and excretion functions

    International Nuclear Information System (INIS)

    After an intake of radioactive material, its behaviour in the human body can be described by mathematical models, where organs, tissues or regions of the body are treated as a chain of linked compartments. The mathematical approach for such metabolic models is usually done through a system of differential equations of first order with constant coefficients. The solutions of this system of equations associates the radionuclide intake, with the fraction excreted or retained in the organ of interest. A computer program - called INCORP and for running in PC compatible microcomputers - was developed in order to find the solutions of such system of equations, using an analytical method based on expansion of series of exponential matrices. The metabolic model presented in the ICRP-30 publication was simulated using the INCORP program, in order to find the respective retention and excretion curves for selected radionuclides. (author)

  6. Dual regulation of muscle glycogen synthase during exercise by activation and compartmentalization

    DEFF Research Database (Denmark)

    Prats, Clara; Helge, Jørn W; Nordby, Pernille;

    2009-01-01

    lateralis muscle of the previously reported mechanism of glycogen metabolism regulation in rabbit tibialis anterior muscle. After overnight low muscle glycogen level and/or in response to exhausting exercise-induced glycogenolysis, GS is associated with spherical structures at the I-band of sarcomeres....

  7. Reconstruction and modeling protein translocation and compartmentalization in Escherichia coli at the genome-scale

    DEFF Research Database (Denmark)

    Liu, Joanne K.; O’Brien, Edward J.; Lerman, Joshua A.;

    2014-01-01

    translocation pathways, (2) assignment of all cellular proteins to one of four compartments (cytoplasm, inner membrane, periplasm, and outer membrane) and a translocation pathway, (3) experimentally determined translocase catalytic and porin diffusion rates, and (4) a novel membrane constraint that reflects...

  8. Changes in cerebral compartmental compliances during mild hypocapnia in patients with traumatic brain injury.

    Science.gov (United States)

    Carrera, Emmanuel; Steiner, Luzius A; Castellani, Gianluca; Smielewski, Peter; Zweifel, Christian; Haubrich, Christina; Pickard, John D; Menon, David K; Czosnyka, Marek

    2011-06-01

    The benefit of induced hyperventilation for intracranial pressure (ICP) control after severe traumatic brain injury (TBI) is controversial. In this study, we investigated the impact of early and sustained hyperventilation on compliances of the cerebral arteries and of the cerebrospinal (CSF) compartment during mild hyperventilation in severe TBI patients. We included 27 severe TBI patients (mean 39.5 ± 3.4 years, 6 women) in whom an increase in ventilation (20% increase in respiratory minute volume) was performed during 50 min as part of a standard clinical CO(2) reactivity test. Using a new mathematical model, cerebral arterial compliance (Ca) and CSF compartment compliance (Ci) were calculated based on the analysis of ICP, arterial blood pressure, and cerebral blood flow velocity waveforms. Hyperventilation initially induced a reduction in ICP (17.5 ± 6.6 vs. 13.9 ± 6.2 mmHg; p sec; p compliances may detect and prevent an adverse ischemic event during hyperventilation. PMID:21204704

  9. Viability conditions for a compartmentalized protometabolic system: a semi-empirical approach.

    Directory of Open Access Journals (Sweden)

    Gabriel Piedrafita

    Full Text Available In this work we attempt to find out the extent to which realistic prebiotic compartments, such as fatty acid vesicles, would constrain the chemical network dynamics that could have sustained a minimal form of metabolism. We combine experimental and simulation results to establish the conditions under which a reaction network with a catalytically closed organization (more specifically, an (M,R-system would overcome the potential problem of self-suffocation that arises from the limited accessibility of nutrients to its internal reaction domain. The relationship between the permeability of the membrane, the lifetime of the key catalysts and their efficiency (reaction rate enhancement turns out to be critical. In particular, we show how permeability values constrain the characteristic time scale of the bounded protometabolic processes. From this concrete and illustrative example we finally extend the discussion to a wider evolutionary context.

  10. Inversion of surface subsidence data to quantify reservoir compartmentalization: A field study

    NARCIS (Netherlands)

    Fokker, P.A.; Visser, K.; Peters, E.; Kunakbayeva, G.; Muntendam-Bos, A.G.

    2010-01-01

    The Roswinkel gas field in the northeastern part of the Netherlands has been in production between 1980 and 2005. Located at about 2100 m depth, it is a severely faulted anticlinal structure, constituting up to 30 reservoir compartments. Due to the complicated nature of this field, there are large u

  11. The construction of next-generation matrices for compartmental epidemic models

    NARCIS (Netherlands)

    Diekmann, O.; Heesterbeek, J.A.P.; Roberts, M.G.

    2010-01-01

    The basic reproduction number R0 is arguably the most important quantity in infectious disease epidemiology. The next-generation matrix (NGM) is the natural basis for the definition and calculation of R0 where finitely many different categories of individuals are recognized. We clear up confusion th

  12. Molecular speciation and tissue compartmentation of zinc in durum wheat grains with contrasting nutritional status

    DEFF Research Database (Denmark)

    Persson, Daniel Pergament; de Bang, Thomas C.; Pedas, Pai R.;

    2016-01-01

    Low concentration of zinc (Zn) in the endosperm of cereals is a major factor contributing to Zn deficiency in human populations. We have investigated how combined Zn and nitrogen (N) fertilization affects the speciation and localization of Zn in durum wheat (Triticum durum). Zn-binding proteins...

  13. Compartmentalization of Science, Power and Social Responsibility as exemplified in the life of J. Robert Oppenheimer.

    Science.gov (United States)

    van de Merwe, Willem; Ream, Todd

    2007-03-01

    Many biographies of J. Robert Oppenheimer have recently been published; each emphasizing some different aspects of his life. Physicists can learn much about physics in the early 1900s and about the practice of physics in society from these biographies. Oppenheimer, the ``father of the atomic bomb,'' seems to have struggled early in life with finding a framework for understanding himself and for finding guidance for making responsible decisions. In this paper, we will briefly consider his upbringing in the Ethical Cultural School, his studies in physics in Europe, passion for poetry, including the influence of the Bhagavad-Gita, and his initial sympathizing with left-wing political groups. In this context, we will consider whether a quality liberal arts education might help physics students formulate their framework to guide them throughout the course of their career in science.

  14. The Green's function formalism as a bridge between single and multi-compartmental modeling

    OpenAIRE

    Wybo, Willem A. M.; Stiefel, Klaus M.; Torben-Nielsen, Benjamin

    2013-01-01

    Neurons are spatially extended structures that receive and process inputs on their dendrites. It is generally accepted that neuronal computations arise from the active integration of synaptic inputs along a dendrite between the input location and the location of spike generation in the axon initial segment. However, many application such as simulations of brain networks, use point-neurons --neurons without a morphological component-- as computational units to keep the conceptual complexity an...

  15. Magnetic resonance imaging demonstrates compartmental muscle mechanisms of human vertical fusional vergence

    OpenAIRE

    Demer, Joseph L.; Clark, Robert A

    2015-01-01

    Vertical fusional vergence (VFV) normally compensates for slight vertical heterophorias. We employed magnetic resonance imaging to clarify extraocular muscle contributions to VFV induced by monocular two-prism diopter (1.15°) base-up prism in 14 normal adults. Fusion during prism viewing requires monocular infraduction. Scans were repeated without prism, and with prism shifted contralaterally. Contractility indicated by morphometric indexes was separately analyzed in medial and lateral vertic...

  16. Compartmentation and dynamics of flavone metabolism in dry and germinated rice seeds.

    Science.gov (United States)

    Galland, Marc; Boutet-Mercey, Stéphanie; Lounifi, Imen; Godin, Béatrice; Balzergue, Sandrine; Grandjean, Olivier; Morin, Halima; Perreau, François; Debeaujon, Isabelle; Rajjou, Loïc

    2014-09-01

    Among secondary metabolites, flavonoids are particularly important for the plant life cycle and could be beneficial for human health. The study of Arabidopsis thaliana transparent testa mutants showed that seed flavonoids are important for environmental adaptation, reactive oxygen species homeostasis, dormancy and longevity. Compared with Arabidopsis and maize (Zea mays L.), far less research has been conducted on rice (Oryza sativa L.) particularly for cultivars with non-pigmented seeds. In this study, we describe the localization, nature and relative abundance of flavonoids in mature and germinated non-pigmented Nipponbare seeds using a combination of confocal microscopy, mass spectrometry and gene expression analysis. The mature seed exclusively accumulates flavones mostly in the embryo and to a lesser extent in the pericarp/testa. Due to the variety of flavone conjugation patterns, 21 different flavones were identified, including sulfated flavones never mentioned before in cereals. Schaftoside (apigenin-6-C-glucoside-8-C-arabinoside) and its two isomers represent nearly 50% of all rice seed flavones and are the only flavonoids accumulated in the pericarp/testa seed compartment. These 21 conjugated flavones showed a very stable profile during rice seed germination sensu stricto, while expression of key flavone synthesis genes strongly increases before the completion of germination. We discuss the potential roles of these rice seed flavones in a seed biology context. PMID:25008975

  17. Molecular speciation and tissue compartmentation of zinc in durum wheat grains with contrasting nutritional status.

    Science.gov (United States)

    Persson, Daniel Pergament; de Bang, Thomas C; Pedas, Pai R; Kutman, Umit Baris; Cakmak, Ismail; Andersen, Birgit; Finnie, Christine; Schjoerring, Jan K; Husted, Søren

    2016-09-01

    Low concentration of zinc (Zn) in the endosperm of cereals is a major factor contributing to Zn deficiency in human populations. We have investigated how combined Zn and nitrogen (N) fertilization affects the speciation and localization of Zn in durum wheat (Triticum durum). Zn-binding proteins were analysed with liquid chromatography ICP-MS and Orbitrap MS(2) , respectively. Laser ablation ICP-MS with simultaneous Zn, sulphur (S) and phosphorus (P) detection was used for bioimaging of Zn and its potential ligands. Increasing the Zn and N supply had a major impact on the Zn concentration in the endosperm, reaching concentrations higher than current breeding targets. The S concentration also increased, but S was only partly co-localized with Zn. The mutual Zn and S enrichment was reflected in substantially more Zn bound to small cysteine-rich proteins (apparent size 10-30 kDa), whereas the response of larger proteins (apparent size > 50 kDa) was only modest. Most of the Zn-responsive proteins were associated with redox- and stress-related processes. This study offers a methodological platform to deepen the understanding of processes behind endosperm Zn enrichment. Novel information is provided on how the localization and speciation of Zn is modified during Zn biofortification of grains. PMID:27159614

  18. Cellular compartmentation of cadmium and zinc in relation to other elements in the hyperaccumulator Arabidopsis halleri

    OpenAIRE

    Küpper, Hendrik; Lombi, Enzo; Zhao, Fang Jie; McGrath, Steve P.

    2000-01-01

    The in vivo substitution of magnesium, the central atom of chlorophyll, by heavy metals (mercury, copper, cadmium, nickel, zinc, lead) leads to a breakdown in photosynthesis and is an important damage mechanism in heavy metal-stressed plants. In this study, a number of methods are presented for the efficient in situ detection of this substitution (i.e. in whole plants or in chloroplasts). While macroscopic observations point to the formation of heavy metal chlorophylls at higher concentration...

  19. Further analysis of open-respirometry systems: an a-compartmental mechanistic approach

    Directory of Open Access Journals (Sweden)

    Chaui-Berlinck J.G.

    2000-01-01

    Full Text Available A system is said to be "instantaneous" when for a given constant input an equilibrium output is obtained after a while. In the meantime, the output is changing from its initial value towards the equilibrium one. This is the transient period of the system and transients are important features of open-respirometry systems. During transients, one cannot compute the input amplitude directly from the output. The existing models (e.g., first or second order dynamics cannot account for many of the features observed in real open-respirometry systems, such as time lag. Also, these models do not explain what should be expected when a system is speeded up or slowed down. The purpose of the present study was to develop a mechanistic approach to the dynamics of open-respirometry systems, employing basic thermodynamic concepts. It is demonstrated that all the main relevant features of the output dynamics are due to and can be adequately explained by a distribution of apparent velocities within the set of molecules travelling along the system. The importance of the rate at which the molecules leave the sensor is explored for the first time. The study approaches the difference in calibrating a system with a continuous input and with a "unit impulse": the former truly reveals the dynamics of the system while the latter represents the first derivative (in time of the former and, thus, cannot adequately be employed in the apparent time-constant determination. Also, we demonstrate why the apparent order of the output changes with volume or flow.

  20. Cilium transition zone proteome reveals compartmentalization and differential dynamics of ciliopathy complexes.

    Science.gov (United States)

    Dean, Samuel; Moreira-Leite, Flavia; Varga, Vladimir; Gull, Keith

    2016-08-30

    The transition zone (TZ) of eukaryotic cilia and flagella is a structural intermediate between the basal body and the axoneme that regulates ciliary traffic. Mutations in genes encoding TZ proteins (TZPs) cause human inherited diseases (ciliopathies). Here, we use the trypanosome to identify TZ components and localize them to TZ subdomains, showing that the Bardet-Biedl syndrome complex (BBSome) is more distal in the TZ than the Meckel syndrome (MKS) complex. Several of the TZPs identified here have human orthologs. Functional analysis shows essential roles for TZPs in motility, in building the axoneme central pair apparatus and in flagellum biogenesis. Analysis using RNAi and HaloTag fusion protein approaches reveals that most TZPs (including the MKS ciliopathy complex) show long-term stable association with the TZ, whereas the BBSome is dynamic. We propose that some Bardet-Biedl syndrome and MKS pleiotropy may be caused by mutations that impact TZP complex dynamics. PMID:27519801

  1. Degeneracy in model parameter estimation for multi-compartmental diffusion in neuronal tissue.

    Science.gov (United States)

    Jelescu, Ileana O; Veraart, Jelle; Fieremans, Els; Novikov, Dmitry S

    2016-01-01

    The ultimate promise of diffusion MRI (dMRI) models is specificity to neuronal microstructure, which may lead to distinct clinical biomarkers using noninvasive imaging. While multi-compartment models are a common approach to interpret water diffusion in the brain in vivo, the estimation of their parameters from the dMRI signal remains an unresolved problem. Practically, even when q space is highly oversampled, nonlinear fit outputs suffer from heavy bias and poor precision. So far, this has been alleviated by fixing some of the model parameters to a priori values, for improved precision at the expense of accuracy. Here we use a representative two-compartment model to show that fitting fails to determine the five model parameters from over 60 measurement points. For the first time, we identify the reasons for this poor performance. The first reason is the existence of two local minima in the parameter space for the objective function of the fitting procedure. These minima correspond to qualitatively different sets of parameters, yet they both lie within biophysically plausible ranges. We show that, at realistic signal-to-noise ratio values, choosing between the two minima based on the associated objective function values is essentially impossible. Second, there is an ensemble of very low objective function values around each of these minima in the form of a pipe. The existence of such a direction in parameter space, along which the objective function profile is very flat, explains the bias and large uncertainty in parameter estimation, and the spurious parameter correlations: in the presence of noise, the minimum can be randomly displaced by a very large amount along each pipe. Our results suggest that the biophysical interpretation of dMRI model parameters crucially depends on establishing which of the minima is closer to the biophysical reality and the size of the uncertainty associated with each parameter. PMID:26615981

  2. Simulation of radon short lived decay daughters' inhalation using the lung compartmental model

    International Nuclear Information System (INIS)

    Radon and its short-lived decay daughters are the main source of radiation on natural ways for population. The radon gas, released from soil, water or construction materials is producing by radioactive decay the following solid daughters: Po-218, Bi-214, Pb-214, and Po-214, which can attach to aerosols, and consequently penetrate the organism by inhalation. The human respiratory tract can be approximated by aid of a compartment model that takes into account the different anatomical structures exposed to contamination and irradiation, as well as the respective physiological processes. This model is associated to a mathematical equation system that describes the behavior of the radioactive material inside the body. The results represent the dose equivalent on different organs and tissues, as a function of subject and the activity performed in contaminating environment. (author)

  3. Plant stem cell niches.

    Science.gov (United States)

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  4. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  5. Lung Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Sharon R. Pine

    2008-01-01

    Full Text Available Lung cancer remains a major cause of cancer-related lethality because of high incidence and recurrence in spite of significant advances in staging and therapies. Recent data indicates that stem cells situated throughout the airways may initiate cancer formation. These putative stem cells maintain protumorigenic characteristics including high proliferative capacity, multipotent differentiation, drug resistance and long lifespan relative to other cells. Stem cell signaling and differentiation pathways are maintained within distinct cancer types, and destabilization of this machinery may participate in maintenance of cancer stem cells. Characterization of lung cancer stem cells is an area of active research and is critical for developing novel therapies. This review summarizes the current knowledge on stem cell signaling pathways and cell markers used to identify the lung cancer stem cells.

  6. Biocompatibility, endocytosis, and intracellular trafficking of mesoporous silica and polystyrene nanoparticles in ovarian cancer cells: effects of size and surface charge groups

    Directory of Open Access Journals (Sweden)

    Ekkapongpisit M

    2012-07-01

    Full Text Available Maneerat Ekkapongpisit,1 Antonino Giovia,1 Carlo Follo,1 Giuseppe Caputo,2,3 Ciro Isidoro11Laboratory of Molecular Pathology and Nanobioimaging, Department of Health Sciences, Università del Piemonte Orientale “A Avogadro”, Novara, 2Dipartimento di Chimica dell’Università di Torino, Torino, 3Cyanine Technology SpA, Torino, ItalyBackground and methods: Nanoparticles engineered to carry both a chemotherapeutic drug and a sensitive imaging probe are valid tools for early detection of cancer cells and to monitor the cytotoxic effects of anticancer treatment simultaneously. Here we report on the effect of size (10–30 nm versus 50 nm, type of material (mesoporous silica versus polystyrene, and surface charge functionalization (none, amine groups, or carboxyl groups on biocompatibility, uptake, compartmentalization, and intracellular retention of fluorescently labeled nanoparticles in cultured human ovarian cancer cells. We also investigated the involvement of caveolae in the mechanism of uptake of nanoparticles.Results: We found that mesoporous silica nanoparticles entered via caveolae-mediated endocytosis and reached the lysosomes; however, while the 50 nm nanoparticles permanently resided within these organelles, the 10 nm nanoparticles soon relocated in the cytoplasm. Naked 10 nm mesoporous silica nanoparticles showed the highest and 50 nm carboxyl-modified mesoporous silica nanoparticles the lowest uptake rates, respectively. Polystyrene nanoparticle uptake also occurred via a caveolae-independent pathway, and was negatively affected by serum. The 30 nm carboxyl-modified polystyrene nanoparticles did not localize in lysosomes and were not toxic, while the 50 nm amine-modified polystyrene nanoparticles accumulated within lysosomes and eventually caused cell death. Ovarian cancer cells expressing caveolin-1 were more likely to endocytose these nanoparticles.Conclusion: These data highlight the importance of considering both the

  7. Stem cells in urology.

    Science.gov (United States)

    Aboushwareb, Tamer; Atala, Anthony

    2008-11-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.

  8. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

    Directory of Open Access Journals (Sweden)

    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  9. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-01-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitu

  10. Assessment of pancreas cells

    Science.gov (United States)

    Vanoss, C. J.

    1978-01-01

    Pancreatic islets were obtained from guinea pig pancreas by the collagenase method and kept alive in tissue culture prior to further studies. Pancreas cell morphology was studied by standard histochemical techniques using light microscopy. Preparative vertical electrophoresis-levitation of dispersed fetal guinea pig pancreas cells was conducted in phosphate buffer containing a heavy water (D20) gradient which does not cause clumping of cells or alter the osmolarity of the buffers. The faster migrating fractions tended to be enriched in beta-cell content. Alpha and delta cells were found to some degree in most fractions. A histogram showing the cell count distribution is included.

  11. Resident Peritoneal NK cells

    OpenAIRE

    Gonzaga, Rosemary; Matzinger, Polly; Perez-Diez, Ainhoa

    2011-01-01

    Here we describe a new population of NK cells that reside in the normal, un-inflamed peritoneal cavity. Phenotypically, they share some similarities with the small population of CD49b negative, CD27 positive immature splenic NK cells, and liver NK cells but differ in their expression of CD62L, TRAIL and EOMES. Functionally, the peritoneal NK cells resemble the immature splenic NK cells in their production of IFN-γ, GM-CSF and TNF-α and in the killing of YAC-1 target cells. We also found that ...

  12. Multipotent adult progenitor cell and stem cell plasticity

    OpenAIRE

    Jahagirdar, Balkrishna N; Verfaillie, Catherine

    2005-01-01

    Stem cells are defined by their biological function. A stem cell is an undifferentiated cell that self-renews to maintain the stem cell pool and at the single-cell level differentiates into more than one mature, functional cell. In addition, when transplanted, a stem cell should be capable of replacing a damaged organ or tissue for the lifetime of the recipient. Some would argue that stem cells should also be capable of functionally integrating into nondamaged tissues. Stem cells are critical...

  13. Epidermal Stem Cells

    Directory of Open Access Journals (Sweden)

    Osman Köse

    2015-03-01

    Full Text Available The epidermis is the outermost layer of the human skin and comprises a multilayered epithelium, the interfollicular epidermis, with associated hair follicles, sebaceous glands, and eccrine sweat glands. There are many origins of stem cells in the skin and skin appendages. These stem cells are localized in different part of the pilosebaseous units and also express many different genes. Epidermal stem cells in the pilosebaseous units not only ensure the maintenance of epidermal homeostasis and hair regeneration, but also contribute to repair of the epidermis after injury. In recent years, human induced pluripotent skin stem cells are produced from the epidermal cells such as keratinocytes, fibroblasts and melanocytes. These cells can be transdifferentiated to embriyonic stem cells. Human induced pluripotent stem cells have potential applications in cell replacement therapy and regenerative medicine. These cells provide a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. In this review, we aimed an overview of epidermal stem cells for better understanding their functions in the skin. Skin will be main organ for using the epidermal cells for regenerative medicine in near future.

  14. The cell cycle as a brake for β-cell regeneration from embryonic stem cells.

    Science.gov (United States)

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-13

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle machinery. Both β cells and ES cells possess unique cell cycle machinery yet with significant contrasts. In this review, we compare the cell cycle control mechanisms in both ES cells and β cells, and highlight the fundamental differences between pluripotent cells of embryonic origin and differentiated β cells. Through critical analysis of the differences of the cell cycle between these two cell types, we propose that the cell cycle of ES cells may act as a brake for β-cell regeneration. Based on these differences, we discuss the potential of modulating the cell cycle of ES cells for the large-scale generation of functionally mature β cells in vitro. Further understanding of the factors that modulate the ES cell cycle will lead to new approaches to enhance the production of functional mature insulin-producing cells, and yield a reliable system to generate bona fide β cells in vitro.

  15. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  16. Toward 'SMART' stem cells.

    Science.gov (United States)

    Cheng, T

    2008-01-01

    Stem cell research is at the heart of regenerative medicine, which holds great promise for the treatment of many devastating disorders. However, in addition to hurdles posed by well-publicized ethical issues, this emerging field presents many biological challenges. What is a stem cell? How are embryonic stem cells different from adult stem cells? What are the physiological bases for therapeutically acceptable stem cells? In this editorial review, I will briefly discuss these superficially simple but actually rather complex issues that surround this fascinating cell type. The goal of this special issue on stem cells in Gene Therapy is to review some fundamental and critical aspects of current stem cell research that have translational potential. PMID:18046429

  17. Cell signaling review series

    Institute of Scientific and Technical Information of China (English)

    Aiming Lin; Zhenggang Liu

    2008-01-01

    @@ Signal transduction is pivotal for many, if not all, fundamental cellular functions including proliferation, differentiation, transformation and programmed cell death. Deregulation of cell signaling may result in certain types of cancers and other human diseases.

  18. Giant Cell Arteritis

    Science.gov (United States)

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  19. Sickle cell anemia.

    OpenAIRE

    ŘÍHOVÁ, Tereza

    2013-01-01

    This thesis is about the disease called sickle cell anemia, or drepanocytosis. In this thesis is described the history of the disease, pathophysiology, laboratory features, various clinical features, diferencial diagnosis, quality of life in sickle cell anemia and therapy.

  20. Sickle Cell Trait

    Science.gov (United States)

    ... About Us Information For... Media Policy Makers Sickle Cell Trait Language: English Español (Spanish) Recommend on Facebook ... the trait on to their children. How Sickle Cell Trait is Inherited If both parents have SCT, ...