Science.gov

Sample records for plant cell differentiation

  1. Using Tissue Culture To Investigate Plant Cell Differentiation and Dedifferentiation.

    ERIC Educational Resources Information Center

    Bozzone, Donna M.

    1997-01-01

    Describes an experimental project that uses plant tissue culture techniques to examine cell differentiation in the carrot. Allows students to gain experience in some important techniques and to explore fundamental questions about cell differentiation. (DDR)

  2. Differential scanning calorimetry of plant cell walls

    SciTech Connect

    Lin, Liangshiou; Varner, J.E. ); Yuen, H.K. )

    1991-03-15

    High-sensitivity differential scanning calorimetry has been used to study the phase transition of cell wall preparations of the elongating and mature regions of soybean hypocotyls and of celery epidermis and collenchyma strands. A step-like transition believed to be glass transition was observed in walls isolated from the elongating region of soybean hypocotyls at 52.9C. Addition of 1 mM CaCl{sub 2} to the cell wall preparation increased the transition temperature to 60.8C and greatly reduced the transition magnitude. In walls from the mature region, the transition was small and occurred at a higher temperature (60.1C). Addition of calcium to the mature region cell wall had little effect on the transition. Based on the known interactions between calcium and pectin, the authors propose that calcium affects the glass transition by binding to the polygalacturonate backbone of wall pectin, resulting in a more rigid wall with a smaller transition at a higher temperature. The mature region either has more calcium in the wall or has more methyl-esterified pectin, making it less responsive to added calcium.

  3. Differentiation of plant graviperceiving and graviresponding cells in altered gravity

    NASA Astrophysics Data System (ADS)

    Kordyum, E. L.; Martyn, G. G.; Shevchenko, G. V.; Kozeko, L. Ye.; Artemenko, O. A.

    2005-08-01

    A main goal of our work was to compare the anatomy and ultrastructure of a root cap, including statocytes (graviperceiving cells), and a root proper meristem and elongation zone (graviresponding cells) of Beta vulgaris seedlings grown in the control and under clinorotation as a root apex is a very convenient model for the study of plant cell gravisensitivity. The comparison of the ultrastructure and topography of cell organelles clearly showed the differences in growth by elongation and differentiation in time and space between statocytes and cortex cells of the distal elongation zone (DEZ), in dependence on their main functions. A root graviperceptive apparatus develops under clinorotation but it does not function. DEZ cells reveal the highest metabolism activity in both variants that can underlie their specific physiological properties and provide cell rapid growth in the central elongation zone.

  4. Evolution of plant conducting cells: perspectives from key regulators of vascular cell differentiation.

    PubMed

    Ohtani, Misato; Akiyoshi, Nobuhiro; Takenaka, Yuto; Sano, Ryosuke; Demura, Taku

    2017-01-01

    One crucial problem that plants faced during their evolution, particularly during the transition to growth on land, was how to transport water, nutrients, metabolites, and small signaling molecules within a large, multicellular body. As a solution to this problem, land plants developed specific tissues for conducting molecules, called water-conducting cells (WCCs) and food-conducting cells (FCCs). The well-developed WCCs and FCCs in extant plants are the tracheary elements and sieve elements, respectively, which are found in vascular plants. Recent molecular genetic studies revealed that transcriptional networks regulate the differentiation of tracheary and sieve elements, and that the networks governing WCC differentiation are largely conserved among land plant species. In this review, we discuss the molecular evolution of plant conducting cells. By focusing on the evolution of the key transcription factors that regulate vascular cell differentiation, the NAC transcription factor VASCULAR-RELATED NAC-DOMAIN for WCCs and the MYB-coiled-coil (CC)-type transcription factor ALTERED PHLOEM DEVELOPMENT for sieve elements, we describe how land plants evolved molecular systems to produce the specialized cells that function as WCCs and FCCs.

  5. Polarity in plant asymmetric cell division: Division orientation and cell fate differentiation.

    PubMed

    Shao, Wanchen; Dong, Juan

    2016-11-01

    Asymmetric cell division (ACD) is universally required for the development of multicellular organisms. Unlike animal cells, plant cells have a rigid cellulosic extracellular matrix, the cell wall, which provides physical support and forms communication routes. This fundamental difference leads to some unique mechanisms in plants for generating asymmetries during cell division. However, plants also utilize intrinsically polarized proteins to regulate asymmetric signaling and cell division, a strategy similar to the differentiation mechanism found in animals. Current progress suggests that common regulatory modes, i.e. protein spontaneous clustering and cytoskeleton reorganization, underlie protein polarization in both animal and plant cells. Despite these commonalities, it is important to note that intrinsic mechanisms in plants are heavily influenced by extrinsic cues. To control physical asymmetry in cell division, although our understanding is fragmentary thus far, plants might have evolved novel polarization strategies to orientate cell division plane. Recent studies also suggest that the phytohormone auxin, one of the most pivotal small molecules in plant development, regulates ACD in plants.

  6. Plant GSK3 proteins regulate xylem cell differentiation downstream of TDIF-TDR signalling

    NASA Astrophysics Data System (ADS)

    Kondo, Yuki; Ito, Tasuku; Nakagami, Hirofumi; Hirakawa, Yuki; Saito, Masato; Tamaki, Takayuki; Shirasu, Ken; Fukuda, Hiroo

    2014-03-01

    During plant radial growth typically seen in trees, procambial and cambial cells act as meristematic cells in the vascular system to self-proliferate and differentiate into xylem cells. These two processes are regulated by a signalling pathway composed of a peptide ligand and its receptor; tracheary element differentiation inhibitory factor (TDIF) and TDIF RECEPTOR (TDR). Here we show that glycogen synthase kinase 3 proteins (GSK3s) are crucial downstream components of the TDIF signalling pathway suppressing xylem differentiation from procambial cells. TDR interacts with GSK3s at the plasma membrane and activates GSK3s in a TDIF-dependent fashion. Consistently, a specific inhibitor of plant GSK3s strongly induces xylem cell differentiation through BRI1-EMS SUPPRESSOR 1 (BES1), a well-known target transcription factor of GSK3s. Our findings provide insight into the regulation of cell fate determination in meristem maintenance.

  7. Plant stem cell maintenance involves direct transcriptional repression of differentiation program.

    PubMed

    Yadav, Ram Kishor; Perales, Mariano; Gruel, Jérémy; Ohno, Carolyn; Heisler, Marcus; Girke, Thomas; Jönsson, Henrik; Reddy, G Venugopala

    2013-01-01

    In animal systems, master regulatory transcription factors (TFs) mediate stem cell maintenance through a direct transcriptional repression of differentiation promoting TFs. Whether similar mechanisms operate in plants is not known. In plants, shoot apical meristems serve as reservoirs of stem cells that provide cells for all above ground organs. WUSCHEL, a homeodomain TF produced in cells of the niche, migrates into adjacent cells where it specifies stem cells. Through high-resolution genomic analysis, we show that WUSCHEL represses a large number of genes that are expressed in differentiating cells including a group of differentiation promoting TFs involved in leaf development. We show that WUS directly binds to the regulatory regions of differentiation promoting TFs; KANADI1, KANADI2, ASYMMETRICLEAVES2 and YABBY3 to repress their expression. Predictions from a computational model, supported by live imaging, reveal that WUS-mediated repression prevents premature differentiation of stem cell progenitors, being part of a minimal regulatory network for meristem maintenance. Our work shows that direct transcriptional repression of differentiation promoting TFs is an evolutionarily conserved logic for stem cell regulation.

  8. How-to-Do-It: Cytokinin Induced Cell Division & Differentiation Using Intact Plants.

    ERIC Educational Resources Information Center

    Bohnsack, Charles W.

    1989-01-01

    Presents a procedure by which cytokinins are used to induce a population of dividing and differentiating cells on the cut surface of the roots of an intact plant. Includes the method used, results, and suggestions for a variety of variables that may be tested. (RT)

  9. Effects of Plants on Osteogenic Differentiation and Mineralization of Periodontal Ligament Cells: A Systematic Review.

    PubMed

    Costa, Cláudio Rodrigues Rezende; Amorim, Bruna Rabelo; de Magalhães, Pérola; De Luca Canto, Graziela; Acevedo, Ana Carolina; Guerra, Eliete Neves Silva

    2016-04-01

    This systematic review aimed to evaluate the effects of plants on osteogenic differentiation and mineralization of human periodontal ligament cells. The included studies were selected using five different electronic databases. The reference list of the included studies was crosschecked, and a partial gray literature search was undertaken using Google Scholar and ProQuest. The methodology of the selected studies was evaluated using GRADE. After a two-step selection process, eight studies were identified. Six different types of plants were reported in the selected studies, which were Morinda citrifolia, Aloe vera, Fructus cnidii, Zanthoxylum schinifolium, Centella asiatica, and Epimedium species. They included five types of isolated plant components: acemannan, osthole, hesperetin, asiaticoside, and icariin. In addition, some active substances of these components were identified as polysaccharides, coumarins, flavonoids, and triterpenes. The studies demonstrated the potential effects of plants on osteogenic differentiation, cell proliferation, mineral deposition, and gene and protein expression. Four studies showed that periodontal ligament cells induce mineral deposition after plant treatment. Although there are few studies on the subject, current evidence suggests that plants are potentially useful for the treatment of periodontal diseases. However, further investigations are required to confirm the promising effect of these plants in regenerative treatments.

  10. Induction of murine embryonic stem cell differentiation by medicinal plant extracts

    PubMed Central

    Reynertson, Kurt A.; Charlson, Mary E.; Gudas, Lorraine J.

    2010-01-01

    Epidemiological evidence indicates that diets high in fruits and vegetables provide a measure of cancer chemoprevention due to phytochemical constituents. Natural products are a rich source of cancer chemotherapy drugs, and primarily target rapidly-cycling tumor cells. Increasing evidence indicates that many cancers contain small populations of resistant, stem-like cells that have the capacity to regenerate tumors following chemotherapy and radiation, and have been linked to the initiation of metastases. Our goal is to discover natural product-based clinical or dietary interventions that selectively target cancer stem cells, inducing differentiation. We adapted an alkaline phosphatase (AP) stain to assay plant extracts for the capacity to induce differentiation in embryonic stem (ES) cells. AP is a characteristic marker of undifferentiated ES cells, and this represents a novel approach to screening medicinal plant extracts. Following a survey of approximately 100 fractions obtained from twelve species of ethnomedically utilized plants, we found fractions from three species that induced differentiation, decreasing AP and transcript levels of pluripotency markers (Nanog, Oct-4, Rex-1). These fractions affected proliferation of murine ES, and human embryonal, prostate, and breast carcinoma cells in a dose-dependent manner. Several phytochemical constituents were isolated; the antioxidant phytochemicals ellagic acid and gallic acid were shown to affect viability of cultured breast carcinoma cells. PMID:20955699

  11. Induction of murine embryonic stem cell differentiation by medicinal plant extracts

    SciTech Connect

    Reynertson, Kurt A.; Charlson, Mary E.; Gudas, Lorraine J.

    2011-01-01

    Epidemiological evidence indicates that diets high in fruits and vegetables provide a measure of cancer chemoprevention due to phytochemical constituents. Natural products are a rich source of cancer chemotherapy drugs, and primarily target rapidly cycling tumor cells. Increasing evidence indicates that many cancers contain small populations of resistant, stem-like cells that have the capacity to regenerate tumors following chemotherapy and radiation, and have been linked to the initiation of metastases. Our goal is to discover natural product-based clinical or dietary interventions that selectively target cancer stem cells, inducing differentiation. We adapted an alkaline phosphatase (AP) stain to assay plant extracts for the capacity to induce differentiation in embryonic stem (ES) cells. AP is a characteristic marker of undifferentiated ES cells, and this represents a novel approach to screening medicinal plant extracts. Following a survey of approximately 100 fractions obtained from 12 species of ethnomedically utilized plants, we found fractions from 3 species that induced differentiation, decreasing AP and transcript levels of pluripotency markers (Nanog, Oct-4, Rex-1). These fractions affected proliferation of murine ES, and human embryonal, prostate, and breast carcinoma cells in a dose-dependent manner. Several phytochemical constituents were isolated; the antioxidant phytochemicals ellagic acid and gallic acid were shown to affect viability of cultured breast carcinoma cells.

  12. Differential distribution of proteins expressed in companion cells in the sieve element-companion cell complex of rice plants.

    PubMed

    Fukuda, Akari; Fujimaki, Syu; Mori, Tomoko; Suzui, Nobuo; Ishiyama, Keiki; Hayakawa, Toshihiko; Yamaya, Tomoyuki; Fujiwara, Toru; Yoneyama, Tadakatsu; Hayashi, Hiroaki

    2005-11-01

    Sieve tubes are comprised of sieve elements, enucleated cells that are incapable of RNA and protein synthesis. The proteins in sieve elements are supplied from the neighboring companion cells through plasmodesmata. In rice plants, it was unclear whether or not all proteins produced in companion cells had the same distribution pattern in the sieve element-companion cell complex. In this study, the distribution pattern of four proteins, beta-glucuronidase (GUS), green fluorescent protein (GFP), thioredoxin h (TRXh) and glutathione S-transferase (GST) were analyzed. The foreign proteins GUS and GFP were expressed in transgenic rice plants under the control of the TRXh gene promoter (PTRXh), a companion cell-specific promoter. Analysis of leaf cross-sections of PTRXh-GUS and PTRXh-GFP plants indicated high accumulation of GUS and GFP, respectively, in companion cells rather than in sieve elements. GUS and GFP were also detected in phloem sap collected from leaf sheaths of the transgenic rice plants, suggesting these proteins could enter sieve elements. Relative amounts of GFP and endogenous phloem proteins, TRXh and GST, in phloem sap and total leaf extracts were compared. Compared to TRXh and GST, GFP content was higher in total leaf extracts, but lower in phloem sap, suggesting that GFP accumulated mainly in companion cells rather than in sieve elements. On the other hand, TRXh and GST appeared to accumulate in sieve elements rather than in companion cells. These results indicate the evidence for differential distribution of proteins between sieve elements and companion cells in rice plants.

  13. Application of atmospheric plasma sources in growth and differentiation of plant and mammalian stem cells

    NASA Astrophysics Data System (ADS)

    Puac, Nevena

    2014-10-01

    The expansion of the plasma medicine and its demand for in-vivo treatments resulted in fast development of various plasma devices that operate at atmospheric pressure. These sources have to fulfill all demands for application on biological samples. One of the sources that meet all the requirements needed for treatment of biological material is plasma needle. Previously, we have used this device for sterilization of planctonic samples of bacteria, MRSA biofilm, for improved differentiation of human periodontal stem cells into osteogenic line and for treatment of plant meristematic cells. It is well known that plasma generates reactive oxygen species (ROS) and reactive nitrogen species (RNS) that strongly affect metabolism of living cells. One of the open issues is to correlate external plasma products (electrons, ions, RNS, ROS, photons, strong fields etc.) with the immediate internal response which triggers or induces effects in the living cell. For that purpose we have studied the kinetics of enzymes which are typical indicators of the identity of reactive species from the plasma created environment that can trigger signal transduction in the cell and ensue cell activity. In collaboration with Suzana Zivkovicm, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; Nenad Selakovic, Institute of Physics, University of Belgrade; Milica Milutinovic, Jelena Boljevic, Institute for Biological Research ``Sinisa Stankovic,'' University of Belgrade; and Gordana Malovic, Zoran Lj. Petrovic, Institute of Physics, University of Belgrade. Grants III41011, ON171037 and ON173024, MESTD, Serbia.

  14. Cooperative antiproliferative and differentiation-enhancing activity of medicinal plant extracts in acute myeloid leukemia cells.

    PubMed

    Zhamanbayeva, Gulzhan T; Aralbayeva, Araylim N; Murzakhmetova, Maira K; Tuleukhanov, Sultan T; Danilenko, Michael

    2016-08-01

    Acute myeloid leukemia (AML) is an aggressive hematopoietic malignancy with poor prognosis and limited treatment options. Sea buckthorn (Hippophae rhamnoides) berries, dog rose (Rosa canina) rosehips, and garden sage (Salvia officinalis) and oregano (Origanum vulgare) aerial parts are widely used in traditional medicine and exhibit antitumor effects in preclinical models. However, these plants remain scarcely tested for antileukemic activity. Here, we show that their water-ethanol leaf extracts reduced the growth and viability of AML cells and, at non-cytotoxic doses, potentiated cell differentiation induced by a low concentration of 1α,25-dihydroxyvitamin D3, the hormonal form of vitamin D, in a cell type-dependent manner. The latter effect was accompanied by upregulation of the vitamin D receptor protein components and its transcriptional activity. Furthermore, at minimally effective doses the extracts cooperated with one another to produce marked cytostatic effects associated with a partial S-phase arrest and a modest induction of apoptosis. In contrast, these combinations only slightly affected the growth and viability of proliferating normal human peripheral blood mononuclear cells. In addition, the extracts strongly inhibited microsomal lipid peroxidation and protected normal erythrocytes against hypoosmotic shock. Our results suggest that further exploration of the enhanced antileukemic effects of the combinations tested here may lead to the development of alternative therapeutic and preventive approaches against AML.

  15. Traffic monitors at the cell periphery: the role of cell walls during early female reproductive cell differentiation in plants.

    PubMed

    Tucker, Matthew R; Koltunow, Anna M G

    2014-02-01

    The formation of female gametes in plants occurs within the ovule, a floral organ that is also the precursor of the seed. Unlike animals, plants lack a typical germline separated from the soma early in development and rely on positional signals, including phytohormones, mobile mRNAs and sRNAs, to direct diploid somatic precursor cells onto a reproductive program. In addition, signals moving between plant cells must overcome the architectural limitations of a cell wall which surrounds the plasma membrane. Recent studies have addressed the molecular and histological signatures of young ovule cells and indicate that dynamic cell wall changes occur over a short developmental window. These changes in cell wall properties impact signal flow and ovule cell identity, thereby aiding the establishment of boundaries between reproductive and somatic ovule domains.

  16. Involvement of the plant antioxidative response in the differential growth sensitivity to salinity of leaves vs roots during cell development.

    PubMed

    Bernstein, Nirit; Shoresh, Michal; Xu, Yan; Huang, Bingru

    2010-10-15

    Sensitivity to salinity varies between plant organs and between cells of different developmental stages within a single organ. The physiological and molecular bases for the differential responses are not known. Exposure of plants to salinity is known to induce formation of reactive oxygen species (ROS), which are involved in damage mechanisms but also in cell growth processes. The objective of this study was to elucidate developmental-stage-specific and organ-specific involvement of oxidative defense in the plant response to salinity in maize (Zea mays L.). Plants were grown in nutrient solution containing 1mM NaCl (control) or 80mM NaCl. The oxidative stress response and damage symptoms along the cell developmental gradient in growing and mature tissue of leaves and roots were examined. Unlike leaves, roots did not suffer oxidative damage in either growing or mature cells and demonstrated reduced antioxidant response. This may reflect different requirements of ROS for growth mechanisms of leaf and root cells. In leaves, growing tissue demonstrated higher stimulation of superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity under salinity than mature tissue, whereas mature tissue demonstrated higher stimulation of catalase. These results indicate differential roles for these ROS-scavenging enzymes at different cell developmental stages. Because ROS are required for cell expansion, the higher increase in SOD and APX activities in the growing leaf cells that resulted in reduction of ROS content under salinity could lead to the inhibition of cell growth under salinity.

  17. Antioxidant extracts of African medicinal plants induce cell cycle arrest and differentiation in B16F10 melanoma cells.

    PubMed

    Gismondi, Angelo; Canuti, Lorena; Impei, Stefania; Di Marco, Gabriele; Kenzo, Maurice; Colizzi, Vittorio; Canini, Antonella

    2013-09-01

    African ethnomedicine is essentially based on the traditional use of vegetal extracts. Since these natural drugs have shown health giving properties, in the present study we increased further the scientific basis supporting these data. We investigated the effects, on murine B16F10 melanoma cells, of plant extracts that were directly obtained by a Cameroon 'traditional healer'. After a preliminary study on the antioxidant functions of these compounds, already abundant in literature, Moringa oleifera Lam., Eremomastax speciosa (Hochst.) Cufod and Aframomum melegueta K. Schum extracts were individually analyzed. We performed laboratory assessments on these medicinal preparations in order to clearly demonstrate their antineoplastic features. All the treatments caused in tumor cells a great reduction in growth and proliferation rate, cell cycle arrest, increase of p53, p21WAF1/Cip1 and p27Kip1 protein levels and induction of differentiation. These results, on the bioactivity and the biochemical characteristics of African plant extracts, may increase the comprehension of indigenous therapeutic practices and represent the first step for the individuation of new inexpensive and natural drugs able to prevent and contrast cancer onset.

  18. Differentiating plant cells switched to proliferation remodel the functional organization of nuclear domains.

    PubMed

    Testillano, P S; González-Melendi, P; Coronado, M J; Seguí-Simarro, J M; Moreno-Risueño, M A; Risueño, M C

    2005-01-01

    The immature pollen grain, the microspore, under stress conditions can switch its developmental program towards proliferation and embryogenesis. The comparison between the gametophytic and sporophytic pathways followed by the microspore permitted us to analyse the nuclear changes in plant differentiating cells when switched to proliferation. The nucleus is highly dynamic, the architecture of its well organised functional domains--condensed chromatin, interchromatin region, nuclear bodies and nucleolus--changing in response to DNA replication, RNA transcription, processing and transport. In the present work, the rearrangements of the nuclear domains during the switch to proliferation have been determined by in situ molecular identification methods for the subcellular localization of chromatin at different functional states, rDNA, elements of the nuclear machinery (PCNA, splicing factors), signalling and stress proteins. The study of the changes in the nuclear domains was determined by a correlative approach at confocal and electron microscopy levels. The results showed that the switch of the developmental program and the activation of the proliferative activity affected the functional organization of the nuclear domains, which accordingly changed their architecture and functional state. A redistribution of components, among them various signalling molecules which targeted structures within the interchromatin region upon translocation from the cytoplasm, was also observed.

  19. Differential recognition of plant cell walls by microbial xylan-specific carbohydrate-binding modules.

    PubMed

    McCartney, Lesley; Blake, Anthony W; Flint, James; Bolam, David N; Boraston, Alisdair B; Gilbert, Harry J; Knox, J Paul

    2006-03-21

    Glycoside hydrolases that degrade plant cell walls have complex molecular architectures in which one or more catalytic modules are appended to noncatalytic carbohydrate-binding modules (CBMs). CBMs promote binding to polysaccharides and potentiate enzymic hydrolysis. Although there are diverse sequence-based families of xylan-binding CBMs, these modules, in general, recognize both decorated and unsubstituted forms of the target polysaccharide, and thus the evolutionary rationale for this diversity is unclear. Using immunohistochemistry to interrogate the specificity of six xylan-binding CBMs for their target polysaccharides in cell walls has revealed considerable differences in the recognition of plant materials between these protein modules. Family 2b and 15 CBMs bind to xylan in secondary cell walls in a range of dicotyledon species, whereas family 4, 6, and 22 CBMs display a more limited capability to bind to secondary cell walls. A family 35 CBM, which displays more restricted ligand specificity against purified xylans than the other five protein modules, reveals a highly distinctive binding pattern to plant material including the recognition of primary cell walls of certain dicotyledons, a feature shared with CBM15. Differences in the specificity of the CBMs toward walls of wheat grain and maize coleoptiles were also evident. The variation in CBM specificity for ligands located in plant cell walls provides a biological rationale for the repertoire of structurally distinct xylan-binding CBMs present in nature, and points to the utility of these modules in probing the molecular architecture of cell walls.

  20. Plant stem cell niches.

    PubMed

    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.

  1. [Investigation of systemic control of plant cell division and differentiation in the model of tumor growth in radish].

    PubMed

    Lutova, L A; Dolgikh, E A; Dodueva, I E; Osipova, M A; Il'ina, E L

    2008-08-01

    The study addresses the control of plant cell division and differentiation using the model of tumor-forming lines of radish. Expression of the genes involved in control of the cell cycle (CycD3), maintenance of meristematic cell activity (STM, WUS, and KNAT1), and primary response to cytokinin (ARR) was studied in inbred radish lines characterized by tumor growth at different stages of development. The influence of exogenic cytokinin on the expression of the genes of interest is analyzed. The possible role of the CycD3, KNAT1, STM, WUS, and ARR5 in tumor formation in radish is discussed.

  2. Differential Top10 promoter regulation by six tetracycline analogues in plant cells

    NASA Technical Reports Server (NTRS)

    Love, John; Allen, George C.; Gatz, Christiane; Thompson, William F.; Brown, C. S. (Principal Investigator)

    2002-01-01

    The effects of five tetracycline analogues, anhydrotetracycline, doxycycline, minocycline, oxytetracycline, and tetracycline, on Top10 promoter activity in NT1 tobacco tissue culture cells have been analysed. The concentration that repressed Top10 promoter activity, the level of transgene repression and the kinetics of transgene de-repression were determined for each analogue, and could not be predicted from in vitro binding affinity to the tetracycline repressor or from comparison with animal cells. Doxycycline had the most potent effect on the Top10 promoter and completely inhibited transgene expression at 4 nmol l(-1). Tetracycline was the most versatile of the analogues tested; tetracycline inhibited the Top10 promoter at 10 nmol l(-1) and was easily washed out to restore Top10-driven expression in 12-24 h. A study was also made of the suitability for plant research of a novel tetracycline analogue, GR33076X. In animal cells, GR33076X de-repressed Top10 promoter activity in the presence of inhibitory concentrations of anhydrotetracycline. In NT1, it is shown that GR 33076X can antagonize repression of the Top10 promoter in the presence of tetracycline, but not of anhydrotetracycline or of doxycycline. Different tetracycline analogues can therefore be used to regulate the Top10 promoter in plant cells and this property may be exploited in planning an optimum course of transgene regulation.

  3. Stomagenesis versus myogenesis: Parallels in intrinsic and extrinsic regulation of transcription factor mediated specialized cell-type differentiation in plants and animals.

    PubMed

    Putarjunan, Aarthi; Torii, Keiko U

    2016-05-01

    Although the last common unicellular ancestor of plants and animals diverged several billion years ago, and while having developed unique developmental programs that facilitate differentiation and proliferation specific to plant and animal systems, there still exists a high degree of conservation in the logic regulating these developmental processes within these two seemingly diverse kingdoms. Stomatal differentiation in plants involves a series of orchestrated cell division events mediated by a family of closely related bHLH transcription factors (TFs) to create a pair of mature guard cells. These TFs are in turn regulated by a number of upstream signaling components that ultimately function to achieve lineage specific differentiation and organized tissue patterning on the plant epidermis. The logic involved in the specification of the myogenic differentiation program in animals is intriguingly similar to stomatal differentiation in plants: Closely-related myogenic bHLHs, known as MRFs (Myogenic Regulatory Factors) provide lineage specificity essential for cell-fate determination. These MRFs, similar to the bHLHs in plants, are regulated by several upstream signaling cascades that succinctly regulate each differentiation step, leading to the production of mature muscle fibers. This review aims at providing a perspective on the emerging parallels in the logic employed by key bHLH transcription factors and their upstream signaling components that function to precisely regulate key cell-state transition events in the stomatal as well as myogenic cell lineages.

  4. Effect of microgravity environment on cell wall regeneration, cell divisions, growth, and differentiation of plants from protoplasts (7-IML-1)

    NASA Technical Reports Server (NTRS)

    Rasmussen, Ole

    1992-01-01

    The primary goal of this project is to investigate if microgravity has any influence on growth and differentiation of protoplasts. Formation of new cell walls on rapeseed protoplasts takes place within the first 24 hours after isolation. Cell division can be observed after 2-4 days and formation of cell aggregates after 5-7 days. Therefore, it is possible during the 7 day IML-1 Mission to investigate if cell wall formation, cell division, and cell differentiation are influenced by microgravity. Protoplasts of rapeseeds and carrot will be prepared shortly before launch and injected into 0.6 ml polyethylene bags. Eight bags are placed in an aluminum block inside the ESA Type 1 container. The containers are placed at 4 C in PTCU's and transferred to orbiter mid-deck. At 4 C all cell processes are slowed down, including cell wall formation. Latest access to the shuttle will be 12 hours before launch. In orbit the containers will be transferred from the PTC box to the 22 C Biorack incubator. The installation of a 1 g centrifuge in Biorack will make it possible to distinguish between effects of near weightlessness and effects caused by cosmic radiation and other space flight factors including vibrations. Parallel control experiments will be carried out on the ground. Other aspects of the experiment are discussed.

  5. The corky root rot pathogen Pyrenochaeta lycopersici secretes a proteinaceous inducer of cell death affecting host plants differentially.

    PubMed

    Clergeot, Pierre-Henri; Schuler, Herwig; Mørtz, Ejvind; Brus, Maja; Vintila, Simina; Ekengren, Sophia

    2012-09-01

    Pathogenic isolates of Pyrenochaeta lycopersici, the causal agent of corky root rot of tomato, secrete cell death in tomato 1 (CDiT1), a homodimeric protein of 35 kDa inducing cell death after infiltration into the leaf apoplast of tomato. CDiT1 was purified by fast protein liquid chromatography, characterized by mass spectrometry and cDNA cloning. Its activity was confirmed after infiltration of an affinity-purified recombinant fusion of the protein with a C-terminal polyhistidine tag. CDiT1 is highly expressed during tomato root infection compared with axenic culture, and has a putative ortholog in other pathogenic Pleosporales species producing proteinaceous toxins that contribute to virulence. Infiltration of CDiT1 into leaves of other plants susceptible to P. lycopersici revealed that the protein affects them differentially. All varieties of cultivated tomato (Solanum lycopersicum) tested were more sensitive to CDiT1 than those of currant tomato (S. pimpinellifolium). Root infection assays showed that varieties of currant tomato are also significantly less prone to intracellular colonization of their root cells by hyphae of P. lycopersici than varieties of cultivated tomato. Therefore, secretion of this novel type of inducer of cell death during penetration of the fungus inside root cells might favor infection of host species that are highly sensitive to this molecule.

  6. Chromosomal differentiation of cells

    SciTech Connect

    1993-12-31

    Chapter 16, discusses the chromosomal differentiation of cells. The chromosomes of differentiated cells have been much less studies than those of meristematic or germline cells, probably because such cells do not usually divide spontaneously. However, in many cases they can be induced to undergo mitosis. 26 refs., 2 figs.

  7. Evaluation of unbound free heme in plant cells by differential acetone extraction.

    PubMed

    Espinas, Nino A; Kobayashi, Koichi; Takahashi, Shigekazu; Mochizuki, Nobuyoshi; Masuda, Tatsuru

    2012-07-01

    Heme functions not only as a prosthetic group of hemoproteins but also as a regulatory molecule, suggesting the presence of 'free' heme. Classically, total non-covalently bound heme is extracted from plant samples with acidic acetone after removal of pigments with basic and neutral acetone. Earlier work proposed that free heme can be selectively extracted into basic acetone. Using authentic hemoproteins, we confirmed that acidic acetone can quantitatively extract heme, while no heme was extracted into neutral acetone. Meanwhile, a certain amount of heme was extracted into basic acetone from hemoglobin and myoglobin. Moreover, basic acetone extracted loosely bound heme from bovine serum albumin, implying that the nature of hemoproteins largely influences heme extraction into basic acetone. Using a highly sensitive heme assay, we found that basic and neutral acetone can extract low levels of heme from plant samples. In addition, neutral acetone quantitatively extracted free heme when it was externally added to plant homogenates. Furthermore, the level of neutral acetone-extractable heme remained unchanged by precursor (5-aminolevulinic acid) feeding, while increased by norflurazon treatment which abolishes chloroplast biogenesis. However, changes in these heme levels did not correlate to genomes uncoupled phenotypes, suggesting that the level of unbound free heme would not affect retrograde signaling from plastids to the nucleus. The present data demonstrate that the combination of single-step acetone extraction following a sensitive heme assay is the ideal method for determining total and free heme in plants.

  8. Importance of symplasmic communication in cell differentiation

    PubMed Central

    Marzec, Marek; Kurczynska, Ewa

    2014-01-01

    Symplasmic communication via plasmodesmata (PD) is part of the system of information exchange between plant cells. Molecules that pass through the PD include ions, some hormones, minerals, amino acids, and sugars but also proteins, transcription factors, and different classes of RNA, and as such PD can participate in the coordination of plant growth and development. This review summarizes the current literature on this subject and the role of PD in signal exchange, the importance of symplasmic communication and symplasmic domains in plant cell differentiation, and highlights the future prospective in the exploration of PD functions in plants. Moreover, this review also describes the potential use of barley root epidermis and non-zygotic embryogenesis in study of symplasmic communication during cell differentiation. PMID:24476959

  9. Rethinking differentiation: Stem cells, regeneration, and plasticity

    PubMed Central

    Alvarado, Alejandro Sánchez; Yamanaka, Shinya

    2014-01-01

    Cell differentiation is an essential process for the development, growth, reproduction and longevity of all multicellular organisms, and its regulation has been the focus of intense investigation for the past 4 decades. The study of natural and induced stem cells has ushered an age of re-examination of what it means to be a stem or a differentiated cell. Past and recent discoveries in plants and animals, as well as novel experimental manipulations are beginning to erode many of these established concepts, and are forcing a re-evaluation of the experimental systems and paradigms presently being used to explore these and other biological process. PMID:24679530

  10. Modeling Stem Cell Myogenic Differentiation

    PubMed Central

    Deshpande, Rajiv S.; Spector, Alexander A.

    2017-01-01

    The process of stem cell myogenesis (transformation into skeletal muscle cells) includes several stages characterized by the expression of certain combinations of myogenic factors. The first part of this process is accompanied by cell division, while the second part is mainly associated with direct differentiation. The mechanical cues are known to enhance stem cell myogenesis, and the paper focuses on the stem cell differentiation under the condition of externally applied strain. The process of stem cell myogenic differentiation is interpreted as the interplay among transcription factors, targeted proteins and strain-generated signaling molecule, and it is described by a kinetic multi-stage model. The model parameters are optimally adjusted by using the available data from the experiment with adipose-derived stem cells subjected to the application of cyclic uniaxial strains of the magnitude of 10%. The modeling results predict the kinetics of the process of myogenic differentiation, including the number of cells in each stage of differentiation and the rates of differentiation from one stage to another for different strains from 4% to 16%. The developed model can help better understand the process of myogenic differentiation and the effects of mechanical cues on stem cell use in muscle therapies. PMID:28106095

  11. Plant vascular development: from early specification to differentiation.

    PubMed

    De Rybel, Bert; Mähönen, Ari Pekka; Helariutta, Yrjö; Weijers, Dolf

    2016-01-01

    Vascular tissues in plants are crucial to provide physical support and to transport water, sugars and hormones and other small signalling molecules throughout the plant. Recent genetic and molecular studies have identified interconnections among some of the major signalling networks that regulate plant vascular development. Using Arabidopsis thaliana as a model system, these studies enable the description of vascular development from the earliest tissue specification events during embryogenesis to the differentiation of phloem and xylem tissues. Moreover, we propose a model for how oriented cell divisions give rise to a three-dimensional vascular bundle within the root meristem.

  12. Plant cell technologies in space: Background, strategies and prospects

    NASA Technical Reports Server (NTRS)

    Kirkorian, A. D.; Scheld, H. W.

    1987-01-01

    An attempt is made to summarize work in plant cell technologies in space. The evolution of concepts and the general principles of plant tissue culture are discussed. The potential for production of high value secondary products by plant cells and differentiated tissue in automated, precisely controlled bioreactors is discussed. The general course of the development of the literature on plant tissue culture is highlighted.

  13. Differentiation of programmed Arabidopsis cells

    PubMed Central

    Xie, De-Yu; Shi, Ming-Zhu

    2012-01-01

    Plants express genes that encode enzymes that catalyse reactions to form plant secondary metabolites in specific cell types. However, the mechanisms of how plants decide their cellular metabolic fate and how cells diversify and specialise their specific secondary metabolites remains largely unknown. Additionally, whether and how an established metabolic program impacts genome-wide reprogramming of plant gene expression is unclear. We recently isolated PAP1-programmed anthocyanin-producing (red) and -free (white) cells from Arabidopsis thaliana; our previous studies have indicated that the PAP1 expression level is similar between these two different cell types. Transcriptional analysis showed that the red cells contain the TTG1-GL3/TT8-PAP1 regulatory complex, which controls anthocyanin biosynthesis; in contrast, the white cells and the wild-type cells lack this entire complex. These data indicate that different regulatory programming underlies the different metabolic states of these cells. In addition, our previous transcriptomic comparison indicated that there is a clear difference in the gene expression profiles of the red and wild-type cells, which is probably a consequence of cell-specific reprogramming. Based on these observations, in this report we discuss the potential mechanisms that underlie the programming and reprogramming of gene expression involved in anthocyanin biosynthesis. PMID:22126737

  14. Changes in nuclear and nucleolar protein content during the growth and differentiation of root parenchyma cells in plant species with different DNA-endoreplication dynamics.

    PubMed

    Marciniak, K; Bilecka, A

    1986-01-01

    Using cytophotometric procedures, we measured the nuclear and nucleolar protein content of successive zones of growth and differentiation in consecutive (1-7 mm) root segments obtained from eight species of the Angiospermae after staining the preparations with Feulgen-Naphthol Yellow S (F-NYS). In meristematic cells the nuclear and nucleolar protein content was found to double during the cell cycle. In species in which differentiation occurs at the same time as nuclear DNA endoreplication, i.e. Vicia faba subsp. minor, V. faba subsp. major, Pisum sativum, Hordeum vulgare and Amaryllis belladonna, the pool of nuclear proteins observed during the G2 phase of the cell cycle was seen in the differentiated zone in nuclei containing 8C DNA. Species in which differentiation is not accompanied by the process of nuclear DNA endoreplication, i.e. Levisticum officinale, Tulipa kaufmanniana and Haemanthus katharinae, exhibited the highest nuclear proteins content during the G2 phase of the cell cycle; comparably high values were not found in the differentiated zone. A decrease in nucleolar protein content was observed during the process of differentiation, this tendency being more evident in the studied species that do not exhibit endoreplication.

  15. Measurement of Total Site Mercury Emissions from a Chlor-Alkali Plant Using Ultraviolet Differential Optical Absorption Spectroscopy and Cell Room Roof-Vent Monitoring

    EPA Science Inventory

    Mercury-cell chlor-alkali plants can emit significant quantities of fugitive elemental mercury vapor to the air as part of production operations and maintenance activities. In the fall of 2006, the U.S. Environmental Protection Agency (EPA) conducted a measurement project at a ch...

  16. A putative Arabidopsis thaliana glycosyltransferase, At4g01220, which is closely related to three plant cell wall-specific xylosyltransferases, is differentially expressed spatially and temporally.

    PubMed

    Fangel, Jonatan U; Petersen, Bent L; Jensen, Niels B; Willats, William G T; Bacic, Antony; Egelund, Jack

    2011-03-01

    Plant cell wall polysaccharides are amongst the most complex, heterogeneous and abundant bio-molecules on earth. This makes the biosynthetic enzymes, namely the glycosyltransferases and polysaccharide synthases, important research targets in plant science and biotechnology. As an initial step to characterize At4g01220, a putative Arabidopsis thaliana encoding glycosyltransferases in CAZy GT-family-77 that is similar to three known xylosyltransferases involved in the biosynthesis of the pectic polysaccharide, rhamnogalacturonan II, we conducted an expression analysis. In transgenic Arabidopsis thaliana plants containing a fusion between the At4g01220 promoter and the gusA reporter gene we found the expression to be spatially and developmentally regulated. Analysis of Nicotiana benthamiana transfected with the At2g01220::YFP fusion protein revealed that the fusion protein resided in a Brefeldin A-sensitive compartment consistent with a sub-cellular location in the Golgi apparatus. In addition, in silico expression analysis from the Genevestigator database revealed that At4g01220 was up-regulated upon treatment with isoxaben, an inhibitor of cellulose synthesis, which, together with a co-expression analysis that identified a number of plant cell wall co-related biosynthetic genes, suggests involvement in cell wall biosynthesis with pectin being a prime candidate. The data presented provide insights into the expression, sub-cellular location and regulation of At4g01220 under various conditions and may help elucidate its specific function.

  17. Germ Cell Differentiation from Pluripotent Cells

    PubMed Central

    Medrano, Jose V.; Pera, Renee A. Reijo; Simón, Carlos

    2014-01-01

    Infertility is a medical condition with an increasing impact in Western societies with causes linked to toxins, genetics, and aging (primarily delay of motherhood). Within the different pathologies that can lead to infertility, poor quality or reduced quantity of gametes plays an important role. Gamete donation and therefore demand on donated sperm and eggs in fertility clinics is increasing. It is hoped that a better understanding of the conditions related to poor gamete quality may allow scientists to design rational treatments. However, to date, relatively little is known about human germ cell development in large part due to the inaccessibility of human development to molecular genetic analysis. It is hoped that pluripotent human embryonic stem cells and induced pluripotent stem cells may provide an accessible in vitro model to study germline development; these cells are able to differentiate to cells of all three primary embryonic germ layers, as well as to germ cells in vitro. We review the state of the art in germline differentiation from pluripotent stem cells. PMID:23329632

  18. Regulators of Tfh Cell Differentiation

    PubMed Central

    Jogdand, Gajendra M.; Mohanty, Suchitra; Devadas, Satish

    2016-01-01

    The follicular helper T (Tfh) cells help is critical for activation of B cells, antibody class switching, and germinal center (GC) formation. The Tfh cells are characterized by the expression of CXC chemokine receptor 5 (CXCR5), ICOS, programed death 1 (PD-1), B cell lymphoma 6 (BCL-6), and IL-21. They are involved in clearing infections and are adversely linked with autoimmune diseases and also have a role in viral replication as well as clearance. On the one hand, Tfh cells are generated from naive CD4+ T cells with sequential steps involving cytokine signaling (IL-21, IL-6, IL-12, activin A), migration, and positioning in the GC by CXCR5, surface receptors (ICOS/ICOSL, signaling lymphocyte activation molecule-associated protein/signaling lymphocyte activation molecule) as well as transcription factor (BCL-6, c-Maf, and signal transducer and activator of transcription 3) signaling and repressor miR155. On the other hand, Tfh generation is negatively regulated at specific steps of Tfh generation by specific cytokine (IL-2, IL-7), surface receptor (PD-1, CTLA-4), transcription factors B lymphocyte maturation protein 1, signal transducer and activator of transcription 5, T-bet, KLF-2 signaling, and repressor miR 146a. Interestingly, miR-17–92 and FOXO1 act as a positive as well as a negative regulator of Tfh differentiation depending on the time of expression and disease specificity. Tfh cells are also generated from the conversion of other effector T cells as exemplified by Th1 cells converting into Tfh during viral infection. The mechanistic details of effector T cells conversion into Tfh are yet to be clear. To manipulate Tfh cells for therapeutic implication and or for effective vaccination strategies, it is important to know positive and negative regulators of Tfh generation. Hence, in this review, we have highlighted and interlinked molecular signaling from cytokines, surface receptors, transcription factors, ubiquitin ligase, and microRNA as positive and

  19. Plant cells in vitro under altered gravity.

    PubMed

    Klymchuk, D O

    1998-07-01

    Establishing the role of gravity in plant requires information about how gravity regulates the metabolism of individual cells. Plant cells and tissues in vitro are valuable models for such purpose. Disrupted intercellular relations in such models have allowed to elucidate both the gravity role in non-specialised to gravity plant cells and the correlative relation role of an intact plant organism. The data obtained from non-numerous space and clinostat experiments with plant cells in vitro have demonstrated that their metabolism is sensitive to g-environment. The most experiments have shown a decrease in the biomass production and cell proliferation of spaceflight samples compared with ground controls, although there is study reporting of increased biomass production in an anise suspension culture and D. carota crown gall tissue culture. At the same time, results of experiments with single carrot cells and tomato callus culture demonstrated similarities in differentiation process in microgravity and in ground controls. Noted ultrastructural arrangement in cells, especially mitochondria and plastids, have been related to altered energy load and functions of organelles in microgravity, as well as changes in the lipid peroxidation and the content of malonic dyaldehyde in a haplopappus tissue culture under altered gravity supposed with modification of membrane structural-functional state. This article focuses on growth aspects of the cultured cells in microgravity and under clinostat conditions and considers those aspects that require further analysis.

  20. Regulation of cell division in higher plants

    SciTech Connect

    Jacobs, T.W.

    1992-01-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant's essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  1. Cell cycle stage-specific differential expression of topoisomerase I in tobacco BY-2 cells and its ectopic overexpression and knockdown unravels its crucial role in plant morphogenesis and development.

    PubMed

    Singh, Badri Nath; Mudgil, Yashwanti; John, Riffat; Achary, V Mohan Murali; Tripathy, Manas Kumar; Sopory, Sudhir K; Reddy, Malireddy K; Kaul, Tanushri

    2015-11-01

    DNA topoisomerases catalyze the inter-conversion of different topological forms of DNA. Cell cycle coupled differential accumulation of topoisomerase I (Topo I) revealed biphasic expression maximum at S-phase and M/G1-phase of cultured synchronized tobacco BY-2 cells. This suggested its active role in resolving topological constrains during DNA replication (S-phase) and chromosome decondensation (M/G1 phase). Immuno-localization revealed high concentrations of Topo I in nucleolus. Propidium iodide staining and Br-UTP incorporation patterns revealed direct correlation between immunofluorescence intensity and rRNA transcription activity within nucleolus. Immuno-stained chromosomes during metaphase and anaphase suggested possible role of Topo I in resolving topological constrains during mitotic chromosome condensation. Inhibitor studies showed that in comparison to Topo I, Topo II was essential in resolving topological constrains during chromosome condensation. Probably, Topo II substituted Topo I functioning to certain extent during chromosome condensation, but not vice-versa. Transgenic Topo I tobacco lines revealed morphological abnormalities and highlighted its crucial role in plant morphogenesis and development.

  2. Pancreatic Differentiation from Murine Embryonic Stem Cells.

    PubMed

    Sakano, Daisuke; Shiraki, Nobuaki; Kume, Shoen

    2016-01-01

    Pluripotent stem cells are considered as a cell source for replacement therapies for pancreatic beta cells and other organs.We identified tetrabenazine (TBZ), vesicular monoamine transporter 2 (VMAT2) inhibitor as a promoter of late-stage differentiation of Pdx1-positive pancreatic progenitor cells into Ngn3-positive endocrine progenitor cells. A cell-permeable cAMP analog, dBu-cAMP promotes beta cell maturation in late stage of differentiation. The induced beta cells can secrete insulin in a glucose-dependent manner.Our protocol consists of a three -step differentiation process. ES cell recapitulate embryonic developmental processes in vitro. Therefore, the ES cell differentiation system is a useful model for the understanding of molecular mechanism of beta-cell differentiation and are useful for application for future regenerative medicine.

  3. Plant and animal stem cells: similar yet different.

    PubMed

    Heidstra, Renze; Sabatini, Sabrina

    2014-05-01

    The astonishingly long lives of plants and their regeneration capacity depend on the activity of plant stem cells. As in animals, stem cells reside in stem cell niches, which produce signals that regulate the balance between self-renewal and the generation of daughter cells that differentiate into new tissues. Plant stem cell niches are located within the meristems, which are organized structures that are responsible for most post-embryonic development. The continuous organ production that is characteristic of plant growth requires a robust regulatory network to keep the balance between pluripotent stem cells and differentiating progeny. Components of this network have now been elucidated and provide a unique opportunity for comparing strategies that were developed in the animal and plant kingdoms, which underlie the logic of stem cell behaviour.

  4. Nuclear Mechanics and Stem Cell Differentiation.

    PubMed

    Mao, Xinjian; Gavara, Nuria; Song, Guanbin

    2015-12-01

    Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.

  5. [EFFECTS OF DIFFERENT CLASSES OF PLANT HORMONES ON MAMMALIAN CELLS].

    PubMed

    Vildanova, M S; Smirnova, E A

    2016-01-01

    Plant hormones are signal molecules of different chemical structure, secreted by plant cells and acting at low concentrations as regulators of plant growth and differentiation. Certain plant hormones are similar to animal hormones or can be produced by animal cells. A number of studies show that the effect of biologically active components of plant origin including plant/phytohormones is much wider than was previously thought, but so far there are no objective criteria for assessing the influence of phytohormones on the physiological state of animal cells. Presented in the survey data show that plant hormones, which have different effects on plant growth and development (jasmonic, abscisic and gibberellic acids), are not neutral to the cells of animal origin, and animal cells response to them may be either positive or negative.

  6. Microtubule dynamics in plant cells.

    PubMed

    Buschmann, Henrik; Sambade, Adrian; Pesquet, Edouard; Calder, Grant; Lloyd, Clive W

    2010-01-01

    This chapter describes some of the choices and unavoidable compromises to be made when studying microtubule dynamics in plant cells. The choice of species still depends very much on the ability to produce transgenic plants and most work has been done in the relatively small cells of Arabidopsis plants or in tobacco BY-2 suspension cells. Fluorescence-tagged microtubule proteins have been used to label entire microtubules, or their plus ends, but there are still few minus-end markers for these acentrosomal cells. Pragmatic decisions have to be made about probes, balancing the efficacy of microtubule labeling against a tendency to overstabilize and bundle the microtubules and even induce helical plant growth. A key limitation in visualizing plant microtubules is the ability to keep plants alive for long periods under the microscope and we describe a biochamber that allows for plant cell growth and development while allowing gas exchange and reducing evaporation. Another major difficulty is the limited fluorescence lifetime and we describe imaging strategies to reduce photobleaching in long-term imaging. We also discuss methods of measuring microtubule dynamics, with emphasis on the behavior of plant-specific microtubule arrays.

  7. Plant cell walls to ethanol.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conversion of plant cell walls to ethanol constitutes generation 2 bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation, and separation. Ultimately, it is desired to combine as man...

  8. Mediators in cell growth and differentiation

    SciTech Connect

    Ford, R.J.; Maizel, A.L.

    1985-01-01

    This book contains papers divided among seven sections. The section headings are: Cell Cycle and Control of Cell Growth, Growth Factors for Nonlymphoid Cells, Colony-Stimulating Factors, Stem Cells and Hematopoiesis, Lymphoid Growth Factors, Growth Factors in Neoplasia, Interferon, and Differentiation in Normal and Neoplastic Cells.

  9. Plant cells as pharmaceutical factories.

    PubMed

    Rischer, Heiko; Häkkinen, Suvi T; Ritala, Anneli; Seppänen-Laakso, Tuulikki; Miralpeix, Bruna; Capell, Teresa; Christou, Paul; Oksman-Caldentey, Kirsi-Marja

    2013-01-01

    Molecules derived from plants make up a sizeable proportion of the drugs currently available on the market. These include a number of secondary metabolite compounds the monetary value of which is very high. New pharmaceuticals often originate in nature. Approximately 50% of new drug entities against cancer or microbial infections are derived from plants or micro-organisms. However, these compounds are structurally often too complex to be economically manufactured by chemical synthesis, and frequently isolation from naturally grown or cultivated plants is not a sustainable option. Therefore the biotechnological production of high-value plant secondary metabolites in cultivated cells is potentially an attractive alternative. Compared to microbial systems eukaryotic organisms such as plants are far more complex, and our understanding of the metabolic pathways in plants and their regulation at the systems level has been rather poor until recently. However, metabolic engineering including advanced multigene transformation techniques and state-of-art metabolomics platforms has given us entirely new tools to exploit plants as Green Factories. Single step engineering may be successful on occasion but in complex pathways, intermediate gene interventions most often do not affect the end product accumulation. In this review we discuss recent developments towards elucidation of complex plant biosynthetic pathways and the production of a number of highvalue pharmaceuticals including paclitaxel, tropane, morphine and terpenoid indole alkaloids in plants and cell cultures.

  10. An Experimental System to Study Cell Differentiation.

    ERIC Educational Resources Information Center

    Bozzone, Donna M.

    1994-01-01

    Uses Dictyostelium discoideum to aid in introducing cell differentiation to students. Students engage in a laboratory exercise that allows them to investigate the means by which embryonic cells choose developmental pathways. (ZWH)

  11. Reprogramming plant cells for endosymbiosis.

    PubMed

    Oldroyd, Giles E D; Harrison, Maria J; Paszkowski, Uta

    2009-05-08

    The establishment of arbuscular mycorrhizal (AM) symbioses, formed by most flowering plants in association with glomeromycotan fungi, and the root-nodule (RN) symbiosis, formed by legume plants and rhizobial bacteria, requires an ongoing molecular dialogue that underpins the reprogramming of root cells for compatibility. In both endosymbioses, there are distinct phases to the interaction, including a presymbiotic anticipation phase and, subsequently, an intraradical accommodation of the microsymbiont. Maintenance of the endosymbiosis then depends on reciprocal nutrient exchange with the microsymbiont-obtaining plant photosynthates in exchange for mineral nutrients: enhanced phosphate and nitrogen uptake from AM fungi and fixed nitrogen from rhizobia. Despite the taxonomically distinct groups of symbionts, commonalities are observed in the signaling components and the modulation of host cell responses in both AM and RN symbioses, reflecting common mechanisms for plant cell reprogramming during endosymbiosis.

  12. Differences in Cell Division Rates Drive the Evolution of Terminal Differentiation in Microbes

    PubMed Central

    Matias Rodrigues, João F.; Rankin, Daniel J.; Rossetti, Valentina; Wagner, Andreas; Bagheri, Homayoun C.

    2012-01-01

    Multicellular differentiated organisms are composed of cells that begin by developing from a single pluripotent germ cell. In many organisms, a proportion of cells differentiate into specialized somatic cells. Whether these cells lose their pluripotency or are able to reverse their differentiated state has important consequences. Reversibly differentiated cells can potentially regenerate parts of an organism and allow reproduction through fragmentation. In many organisms, however, somatic differentiation is terminal, thereby restricting the developmental paths to reproduction. The reason why terminal differentiation is a common developmental strategy remains unexplored. To understand the conditions that affect the evolution of terminal versus reversible differentiation, we developed a computational model inspired by differentiating cyanobacteria. We simulated the evolution of a population of two cell types –nitrogen fixing or photosynthetic– that exchange resources. The traits that control differentiation rates between cell types are allowed to evolve in the model. Although the topology of cell interactions and differentiation costs play a role in the evolution of terminal and reversible differentiation, the most important factor is the difference in division rates between cell types. Faster dividing cells always evolve to become the germ line. Our results explain why most multicellular differentiated cyanobacteria have terminally differentiated cells, while some have reversibly differentiated cells. We further observed that symbioses involving two cooperating lineages can evolve under conditions where aggregate size, connectivity, and differentiation costs are high. This may explain why plants engage in symbiotic interactions with diazotrophic bacteria. PMID:22511858

  13. Sumoylation differentially regulates Sp1 to control cell differentiation

    PubMed Central

    Gong, Lili; Ji, Wei-Ke; Hu, Xiao-Hui; Hu, Wen-Feng; Tang, Xiang-Cheng; Huang, Zhao-Xia; Li, Ling; Liu, Mugen; Xiang, Shi-Hua; Wu, Erxi; Woodward, Zachary; Liu, Yi-Zhi; Nguyen, Quan Dong; Li, David Wan-Cheng

    2014-01-01

    The mammalian small ubiquitin-like modifiers (SUMOs) are actively involved in regulating differentiation of different cell types. However, the functional differences between SUMO isoforms and their mechanisms of action remain largely unknown. Using the ocular lens as a model system, we demonstrate that different SUMOs display distinct functions in regulating differentiation of epithelial cells into fiber cells. During lens differentiation, SUMO1 and SUMO2/3 displayed different expression, localization, and targets, suggesting differential functions. Indeed, overexpression of SUMO2/3, but not SUMO1, inhibited basic (b) FGF-induced cell differentiation. In contrast, knockdown of SUMO1, but not SUMO2/3, also inhibited bFGF action. Mechanistically, specificity protein 1 (Sp1), a major transcription factor that controls expression of lens-specific genes such as β-crystallins, was positively regulated by SUMO1 but negatively regulated by SUMO2. SUMO2 was found to inhibit Sp1 functions through several mechanisms: sumoylating it at K683 to attenuate DNA binding, and at K16 to increase its turnover. SUMO2 also interfered with the interaction between Sp1 and the coactivator, p300, and recruited a repressor, Sp3 to β-crystallin gene promoters, to negatively regulate their expression. Thus, stable SUMO1, but diminishing SUMO2/3, during lens development is necessary for normal lens differentiation. In support of this conclusion, SUMO1 and Sp1 formed complexes during early and later stages of lens development. In contrast, an interaction between SUMO2/3 and Sp1 was detected only during the initial lens vesicle stage. Together, our results establish distinct roles of different SUMO isoforms and demonstrate for the first time, to our knowledge, that Sp1 acts as a major transcription factor target for SUMO control of cell differentiation. PMID:24706897

  14. Differential distribution of amino acids in plants.

    PubMed

    Kumar, Vinod; Sharma, Anket; Kaur, Ravdeep; Thukral, Ashwani Kumar; Bhardwaj, Renu; Ahmad, Parvaiz

    2017-05-01

    Plants are a rich source of amino acids and their individual abundance in plants is of great significance especially in terms of food. Therefore, it is of utmost necessity to create a database of the relative amino acid contents in plants as reported in literature. Since in most of the cases complete analysis of profiles of amino acids in plants was not reported, the units used and the methods applied and the plant parts used were different, amino acid contents were converted into relative units with respect to lysine for statistical analysis. The most abundant amino acids in plants are glutamic acid and aspartic acid. Pearson's correlation analysis among different amino acids showed that there were no negative correlations between the amino acids. Cluster analysis (CA) applied to relative amino acid contents of different families. Alismataceae, Cyperaceae, Capparaceae and Cactaceae families had close proximity with each other on the basis of their relative amino acid contents. First three components of principal component analysis (PCA) explained 79.5% of the total variance. Factor analysis (FA) explained four main underlying factors for amino acid analysis. Factor-1 accounted for 29.4% of the total variance and had maximum loadings on glycine, isoleucine, leucine, threonine and valine. Factor-2 explained 25.8% of the total variance and had maximum loadings on alanine, aspartic acid, serine and tyrosine. 14.2% of the total variance was explained by factor-3 and had maximum loadings on arginine and histidine. Factor-4 accounted 8.3% of the total variance and had maximum loading on the proline amino acid. The relative content of different amino acids presented in this paper is alanine (1.4), arginine (1.8), asparagine (0.7), aspartic acid (2.4), cysteine (0.5), glutamic acid (2.8), glutamine (0.6), glycine (1.0), histidine (0.5), isoleucine (0.9), leucine (1.7), lysine (1.0), methionine (0.4), phenylalanine (0.9), proline (1.1), serine (1.0), threonine (1

  15. [Basal cell carcinoma with matrical differentiation].

    PubMed

    Goldman-Lévy, Gabrielle; Frouin, Eric; Soubeyran, Isabelle; Maury, Géraldine; Guillot, Bernard; Costes, Valérie

    2015-04-01

    Basal cell carcinoma with matrical differentiation is a very rare variant of basal cell carcinoma. To our knowledge, less than 30 cases have been reported. This tumor is composed of basaloid lobules showing a differentiation toward the pilar matrix cells. Recently, it has been demonstrated that beta-catenin would interfer with physiopathogenesis of matrical tumors, in particular pilomatricomas, but also basal cell carcinomas with matrical differentiation. This is a new case, with immunohistochemical and molecular analysis of beta-catenin, in order to explain its histogenesis.

  16. Mapping microscopic order in plant and mammalian cells and tissues: novel differential polarization attachment for new generation confocal microscopes (DP-LSM)

    NASA Astrophysics Data System (ADS)

    Steinbach, G.; Pawlak, K.; Pomozi, I.; Tóth, E. A.; Molnár, A.; Matkó, J.; Garab, G.

    2014-03-01

    Elucidation of the molecular architecture of complex, highly organized molecular macro-assemblies is an important, basic task for biology. Differential polarization (DP) measurements, such as linear (LD) and circular dichroism (CD) or the anisotropy of the fluorescence emission (r), which can be carried out in a dichrograph or spectrofluorimeter, respectively, carry unique, spatially averaged information about the molecular organization of the sample. For inhomogeneous samples—e.g. cells and tissues—measurements on macroscopic scale are not satisfactory, and in some cases not feasible, thus microscopic techniques must be applied. The microscopic DP-imaging technique, when based on confocal laser scanning microscope (LSM), allows the pixel by pixel mapping of anisotropy of a sample in 2D and 3D. The first DP-LSM configuration, which, in fluorescence mode, allowed confocal imaging of different DP quantities in real-time, without interfering with the ‘conventional’ imaging, was built on a Zeiss LSM410. It was demonstrated to be capable of determining non-confocally the linear birefringence (LB) or LD of a sample and, confocally, its FDLD (fluorescence detected LD), the degree of polarization (P) and the anisotropy of the fluorescence emission (r), following polarized and non-polarized excitation, respectively (Steinbach et al 2009 Acta Histochem.111 316-25). This DP-LSM configuration, however, cannot simply be adopted to new generation microscopes with considerably more compact structures. As shown here, for an Olympus FV500, we designed an easy-to-install DP attachment to determine LB, LD, FDLD and r, in new-generation confocal microscopes, which, in principle, can be complemented with a P-imaging unit, but specifically to the brand and type of LSM.

  17. Optimal design of proportional-integral controllers for stand-alone solid oxide fuel cell power plant using differential evolution algorithm.

    PubMed

    Ahmed, Ashik; Ullah, Md Shahid

    2016-01-01

    This paper proposes the application of differential evolution (DE) algorithm for the optimal tuning of proportional-integral (PI) controller designed to improve the small signal dynamic response of a stand-alone solid oxide fuel cell (SOFC) system. The small signal model of the study system is derived and considered for the controller design as the target here is to track small variations in SOFC load current. Two PI controllers are incorporated in the feedback loops of hydrogen and oxygen partial pressures with an aim to improve the small signal dynamic responses. The controller design problem is formulated as the minimization of an eigenvalue based objective function where the target is to find out the optimal gains of the PI controllers in such a way that the discrepancy of the obtained and desired eigenvalues are minimized. Eigenvalue and time domain simulations are presented for both open-loop and closed loop systems. To test the efficacy of DE over other optimization tools, the results obtained with DE are compared with those obtained by particle swarm optimization (PSO) algorithm and invasive weed optimization (IWO) algorithm. Three different types of load disturbances are considered for the time domain based results to investigate the performances of different optimizers under different sorts of load variations. Moreover, non-parametric statistical analyses, namely, one sample Kolmogorov-Smirnov (KS) test and paired sample t test are used to identify the statistical advantage of one optimizer over the other for the problem under study. The presented results suggest the supremacy of DE over PSO and IWO in finding the optimal solution.

  18. The Mechanisms of M-cell Differentiation

    PubMed Central

    KANAYA, Takashi; OHNO, Hiroshi

    2014-01-01

    Intestinal M (microfold or membranous) cells are an enigmatic lineage of intestinal epithelial cells that initiate mucosal immune responses through the uptake and transcytosis of luminal antigens. Due to their rarity, the mechanisms of M-cell function and differentiation are poorly understood. To overcome this problem, experimental strategies to enrich for M-cells have been established. Transcriptome analyses have provided valuable insight, especially on the receptors for antigen uptake, and such studies have broadened our knowledge of M-cell function. In another line of investigation, we and others have begun to dissect the molecular pathways of M-cell differentiation. Among them, receptor activator of NF-κB ligand (RANKL) has been identified as an essential factor for M-cell differentiation. We have focused on the M-cell inducible activity of RANKL and have been able to observe temporal transitions during M-cell differentiation by using in vivo ectopic M-cell differentiation induced by exogenous RANKL treatment. We have found that the ets-family transcription factor Spi-B is essential for functional maturation of M cells. In the absence of Spi-B, the immune response to Salmonella Typhimurium is severely impaired, suggesting that M cells are important for maintaining intestinal homeostasis. PMID:25032083

  19. Prenylation is required for polar cell elongation, cell adhesion, and differentiation in Physcomitrella patens.

    PubMed

    Thole, Julie M; Perroud, Pierre-Francois; Quatrano, Ralph S; Running, Mark P

    2014-05-01

    Protein prenylation is required for a variety of growth and developmental processes in flowering plants. Here we report the consequences of loss of function of all known prenylation subunits in the moss Physcomitrella patens. As in Arabidopsis, protein farnesyltransferase and protein geranylgeranyltransferase type I are not required for viability. However, protein geranylgeranyltransferase type I activity is required for cell adhesion, polar cell elongation, and cell differentiation. Loss of protein geranylgeranyltransferase activity results in colonies of round, single-celled organisms that resemble unicellular algae. The loss of protein farnesylation is not as severe but also results in polar cell elongation and differentiation defects. The complete loss of Rab geranylgeranyltransferase activity appears to be lethal in P. patens. Labeling with antibodies to cell wall components support the lack of polarity establishment and the undifferentiated state of geranylgeranyltransferase type I mutant plants. Our results show that prenylated proteins play key roles in P. patens development and differentiation processes.

  20. Schwann cells induce neuronal differentiation of bone marrow stromal cells.

    PubMed

    Zurita, Mercedes; Vaquero, Jesús; Oya, Santiago; Miguel, Miriam

    2005-04-04

    Bone marrow stromal cells are multipotent stem cells that have the potential to differentiate into bone, cartilage, fat and muscle. Recently, bone marrow stromal cells have been shown to have the capacity to differentiate into neurons under specific experimental conditions, using chemical factors. We now describe how bone marrow stromal cells can be induced to differentiate into neuron-like cells when they are co-cultured with Schwann cells. When compared with chemical differentiation, expression of neuronal differentiation markers begins later, but one week after beginning co-culture, most bone marrow stromal cells showed a typical neuronal morphology. Our present findings support the transdifferentiation of bone marrow stromal cells, and the potential utility of these cells for the treatment of degenerative and acquired disorders of the nervous system.

  1. Cisplatin Induces Differentiation of Breast Cancer Cells

    PubMed Central

    Prabhakaran, Praseetha; Hassiotou, Foteini; Blancafort, Pilar; Filgueira, Luis

    2013-01-01

    Breast tumors are heterogeneous including cells with stem cell properties and more differentiated cells. This heterogeneity is reflected into the molecular breast cancer subtypes. Breast cancer stem cells are resistant to chemotherapy, thus recent efforts are focusing on identifying treatments that shift them toward a more differentiated phenotype, making them more susceptible to chemotherapy. We examined whether the drug cisplatin induces differentiation in breast cancer cell lines that represent different breast cancer subtypes. We used three cell lines representing triple-negative breast cancers, BT-549 and MDA-MB-231 (claudin-low), and MDA-MB-468 (basal-like), along with estrogen and progesterone receptor positive MCF-7 cells (luminal). Cisplatin was applied at 2.5, 5, 10, and 20 μM, and cell viability and proliferation were measured using MTS and BrdU assays, respectively. The effect of cisplatin on the cellular hierarchy was examined by flow cytometry, immunofluorescence and qRT-PCR. Cisplatin treatment of 10 and 20 μM reduced cell viability by 36–51% and proliferation capacity by 36–67%. Treatment with cisplatin resulted in 12–67% down-regulation of stem cell markers (CD49f, SSEA4) and 10–130% up-regulation of differentiation markers (CK18, SMA, β-tubulin). At the mRNA level, CD49f was down-regulated whilst β-tubulin was up-regulated in the claudin-low cell lines. SSEA4 protein expression decreased upon cisplatin treatment, but SSEA4 mRNA expression increased indicating a differential regulation of cisplatin at the post-transcriptional level. It is concluded that cisplatin reduces breast cancer cell survival and induces differentiation of stem/progenitor cell subpopulations within breast cancer cell lines. These effects indicate the potential of this drug to target specific chemotherapy-resistant cells within a tumor. PMID:23761858

  2. DNA repair in murine embryonic stem cells and differentiated cells

    SciTech Connect

    Tichy, Elisia D. Stambrook, Peter J.

    2008-06-10

    Embryonic stem (ES) cells are rapidly proliferating, self-renewing cells that have the capacity to differentiate into all three germ layers to form the embryo proper. Since these cells are critical for embryo formation, they must have robust prophylactic mechanisms to ensure that their genomic integrity is preserved. Indeed, several studies have suggested that ES cells are hypersensitive to DNA damaging agents and readily undergo apoptosis to eliminate damaged cells from the population. Other evidence suggests that DNA damage can cause premature differentiation in these cells. Several laboratories have also begun to investigate the role of DNA repair in the maintenance of ES cell genomic integrity. It does appear that ES cells differ in their capacity to repair damaged DNA compared to differentiated cells. This minireview focuses on repair mechanisms ES cells may use to help preserve genomic integrity and compares available data regarding these mechanisms with those utilized by differentiated cells.

  3. Rho-GTPase-regulated vesicle trafficking in plant cell polarity.

    PubMed

    Chen, Xu; Friml, Jiří

    2014-02-01

    ROPs (Rho of plants) belong to a large family of plant-specific Rho-like small GTPases that function as essential molecular switches to control diverse cellular processes including cytoskeleton organization, cell polarization, cytokinesis, cell differentiation and vesicle trafficking. Although the machineries of vesicle trafficking and cell polarity in plants have been individually well addressed, how ROPs co-ordinate those processes is still largely unclear. Recent progress has been made towards an understanding of the co-ordination of ROP signalling and trafficking of PIN (PINFORMED) transporters for the plant hormone auxin in both root and leaf pavement cells. PIN transporters constantly shuttle between the endosomal compartments and the polar plasma membrane domains, therefore the modulation of PIN-dependent auxin transport between cells is a main developmental output of ROP-regulated vesicle trafficking. The present review focuses on these cellular mechanisms, especially the integration of ROP-based vesicle trafficking and plant cell polarity.

  4. Epigenetic memory and cell fate reprogramming in plants

    PubMed Central

    Roudier, François

    2017-01-01

    Abstract Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration. PMID:28316791

  5. Epigenetic memory and cell fate reprogramming in plants.

    PubMed

    Birnbaum, Kenneth D; Roudier, François

    2017-02-01

    Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration.

  6. Activin A programs human TFH cell differentiation

    PubMed Central

    Locci, Michela; Wu, Jennifer; Arumemi, Fortuna; Mikulski, Zbigniew; Dahlberg, Carol; Miller, Andrew T.; Crotty, Shane

    2016-01-01

    SUMMARY Follicular helper T (TFH) cells are CD4+ T cells specialized in helping B cells and are associated both with protective antibody responses and autoimmune diseases. The promise of targeting TFH cells therapeutically has been limited by fragmentary understanding of extrinsic signals regulating human TFH cell differentiation. A screen of a human protein library identified activin A as new regulator of TFH cell differentiation. Activin A orchestrated expression of multiple TFH-associated genes, independently or in concert with additional signals. TFH programming by activin A was antagonized by the cytokine IL-2. Activin A’s capacity to drive TFH cell differentiation in vitro was conserved for non-human primates but not mice. Finally, activin A-induced TFH programming was dependent on SMAD2 and SMAD3 signaling and blocked by pharmacological inhibitors. PMID:27376469

  7. Cell proliferation and differentiation in chemical leukemogenesis

    NASA Technical Reports Server (NTRS)

    Irons, R. D.; Stillman, W. S.; Clarkson, T. W. (Principal Investigator)

    1993-01-01

    In tissues such as bone marrow with normally high rates of cell division, proliferation is tightly coordinated with cell differentiation. Survival, proliferation and differentiation of early hematopoietic progenitor cells depend on the growth factors, interleukin 3 (IL-3) and/or granulocyte-macrophage colony stimulating factor (GM-CSF) and their synergism with other cytokines. We provide evidence that a characteristic shared by a diverse group of compounds with demonstrated leukemogenic potential is the ability to act synergistically with GM-CSF. This results in an increase in recruitment of a resting population of hematopoietic progenitor cells normally unresponsive to the cytokine and a twofold increase in the size of the proliferating cell population normally regarded to be at risk of transformation in leukemogenesis. These findings support the possibility that transient alterations in hematopoietic progenitor cell differentiation may be an important factor in the early stages of development of leukemia secondary to chemical or drug exposure.

  8. A novel system for xylem cell differentiation in Arabidopsis thaliana.

    PubMed

    Kondo, Yuki; Fujita, Takashi; Sugiyama, Munetaka; Fukuda, Hiroo

    2015-04-01

    During vascular development, procambial and cambial cells give rise to xylem and phloem cells. Because the vascular tissue is deeply embedded, it has been difficult to analyze the processes of vascular development in detail. Here, we establish a novel in vitro experimental system in which vascular development is induced in Arabidopsis thaliana leaf-disk cultures using bikinin, an inhibitor of glycogen synthase kinase 3 proteins. Transcriptome analysis reveals that mesophyll cells in leaf disks synchronously turn into procambial cells and then differentiate into tracheary elements. Leaf-disk cultures from plants expressing the procambial cell markers TDR(pro):GUS and TDR(pro):YFP can be used for spatiotemporal visualization of procambial cell formation. Further analysis with the tdr mutant and TDIF (tracheary element differentiation inhibitory factor) indicates that the key signaling TDIF-TDR-GSK3s regulates xylem differentiation in leaf-disk cultures. This new culture system can be combined with analysis using the rich material resources for Arabidopsis including cell-marker lines and mutants, thus offering a powerful tool for analyzing xylem cell differentiation.

  9. Hepatic Differentiation from Human Ips Cells Using M15 Cells.

    PubMed

    Umeda, Kahoko; Shiraki, Nobuaki; Kume, Shoen

    2016-01-01

    Here, we describe a procedure of human iPS cells differentiation into the definitive endoderm, further into albumin-expressing and albumin-secreting hepatocyte, using M15, a mesonephros- derived cell line. Approximately 90 % of human iPS cells differentiated into SOX17-positive definitive endoderm then approximately 50 % of cells became albumin-positive cells, and secreted ALB protein. This M15 feeder system for endoderm and hepatic differentiation is a simple and efficient method, and useful for elucidating molecular mechanisms for hepatic fate decision, and could represent an attractive approach for a surrogate cell source for pharmaceutical studies.

  10. Cancer stem cells and differentiation therapy.

    PubMed

    Sell, Stewart

    2006-01-01

    Cancers arise from stem cells in adult tissues and the cells that make up a cancer reflect the same stem cell --> progeny --> differentiation progression observed in normal tissues. All adult tissues are made up of lineages of cells consisting of tissue stem cells and their progeny (transit-amplifying cells and terminally differentiated cells); the number of new cells produced in normal tissue lineages roughly equals the number of old cells that die. Cancers result from maturation arrest of this process, resulting in continued proliferation of cells and a failure to differentiate and die. The biological behavior, morphological appearance, and clinical course of a cancer depend on the stage of maturation at which the genetic lesion is activated. This review makes a comparison of cancer cells to embryonic stem cells and to adult tis sue stem cells while addressing two basic questions: (1) Where do cancers come from?, and (2) How do cancers grow? The answers to these questions are critical to the development of approaches to the detection, prevention, and treatment of cancer.

  11. The PLETHORA Gene Regulatory Network Guides Growth and Cell Differentiation in Arabidopsis Roots[OPEN

    PubMed Central

    Sanchez-Perez, Gabino F.; Rutjens, Bas; Gorte, Maartje; Prasad, Kalika; Bao, Dongping; Timmermans-Hereijgers, Johanna L.P.M.; Maeo, Kenichiro; Nakamura, Kenzo; Shimotohno, Akie; Pencik, Ales; van Heesch, Sebastiaan; de Bruijn, Ewart; Cuppen, Edwin; Willemsen, Viola

    2016-01-01

    Organ formation in animals and plants relies on precise control of cell state transitions to turn stem cell daughters into fully differentiated cells. In plants, cells cannot rearrange due to shared cell walls. Thus, differentiation progression and the accompanying cell expansion must be tightly coordinated across tissues. PLETHORA (PLT) transcription factor gradients are unique in their ability to guide the progression of cell differentiation at different positions in the growing Arabidopsis thaliana root, which contrasts with well-described transcription factor gradients in animals specifying distinct cell fates within an essentially static context. To understand the output of the PLT gradient, we studied the gene set transcriptionally controlled by PLTs. Our work reveals how the PLT gradient can regulate cell state by region-specific induction of cell proliferation genes and repression of differentiation. Moreover, PLT targets include major patterning genes and autoregulatory feedback components, enforcing their role as master regulators of organ development. PMID:27920338

  12. Programmed cell death in plant reproduction.

    PubMed

    Wu, H M; Cheun, A Y

    2000-10-01

    Reproductive development is a rich arena to showcase programmed cell death in plants. After floral induction, the first act of reproductive development in some plants is the selective killing of cells destined to differentiate into an unwanted sexual organ. Production of functional pollen grains relies significantly on deterioration and death of the anther tapetum, a tissue whose main function appears to nurture and decorate the pollen grains with critical surface molecules. Degeneration and death in a number of anther tissues result ultimately in anther rupture and dispersal of pollen grains. Female sporogenesis frequently begins with the death of all but one of the meiotic derivatives, with surrounding nucellar cells degenerating in concert with embryo sac expansion. Female tissues that interact with pollen undergo dramatic degeneration, including death, to ensure the encounter of compatible male and female gametes. Pollen and pistil interact to kill invading pollen from an incompatible source. Most observations on cell death in reproductive tissues have been on the histological and cytological levels. We discuss various cell death phenomena in reproductive development with a view towards understanding the biochemical and molecular mechanisms that underlie these processes.

  13. Chromatin dynamics during cellular differentiation in the female reproductive lineage of flowering plants.

    PubMed

    Baroux, Célia; Autran, Daphné

    2015-07-01

    Sexual reproduction in flowering plants offers a number of remarkable aspects to developmental biologists. First, the spore mother cells - precursors of the plant reproductive lineage - are specified late in development, as opposed to precocious germline isolation during embryogenesis in most animals. Second, unlike in most animals where meiosis directly produces gametes, plant meiosis entails the differentiation of a multicellular, haploid gametophyte, within which gametic as well as non-gametic accessory cells are formed. These observations raise the question of the factors inducing and modus operandi of cell fate transitions that originate in floral tissues and gametophytes, respectively. Cell fate transitions in the reproductive lineage imply cellular reprogramming operating at the physiological, cytological and transcriptome level, but also at the chromatin level. A number of observations point to large-scale chromatin reorganization events associated with cellular differentiation of the female spore mother cells and of the female gametes. These include a reorganization of the heterochromatin compartment, the genome-wide alteration of the histone modification landscape, and the remodeling of nucleosome composition. The dynamic expression of DNA methyltransferases and actors of small RNA pathways also suggest additional, global epigenetic alterations that remain to be characterized. Are these events a cause or a consequence of cellular differentiation, and how do they contribute to cell fate transition? Does chromatin dynamics induce competence for immediate cellular functions (meiosis, fertilization), or does it also contribute long-term effects in cellular identity and developmental competence of the reproductive lineage? This review attempts to review these fascinating questions.

  14. Differential effects of lenalidomide during plasma cell differentiation

    PubMed Central

    Jourdan, Michel; Cren, Maïlys; Schafer, Peter; Robert, Nicolas; Duperray, Christophe; Vincent, Laure; Ceballos, Patrice; Cartron, Guillaume; Rossi, Jean-François; Moreaux, Jérôme; Chopra, Rajesh; Klein, Bernard

    2016-01-01

    Thalidomide, lenalidomide and pomalidomide have greatly improved the outcome of patients with multiple myeloma. However, their effects on plasma cells, the healthy counterpart of myeloma cells, are unknown. Here, we investigated lenalidomide effects on normal human plasma cell generation using an in vitro model. Lenalidomide inhibited the generation of pre-plasmablasts and early plasma cells, while it moderately affected plasmablast production. It also reduced the expression level of Ikaros, Aiolos, and IRF4 transcription factors, in plasmablasts and early plasma cells. This suggests that their differential sensitivity to lenalidomide is not due to a difference in Ikaros or Aiolos degradation. Lenalidomide also inhibited long-lived plasma cell generation, but did not impair their long-term survival once generated. This last observation is in agreement with the finding that lenalidomide treatment for 3-18 months did not affect the bone marrow healthy plasma cell count in allografted patients with multiple myeloma. Our findings should prompt to investigate whether lenalidomide resistance in patients with multiple myeloma could be associated with the emergence of malignant plasmablasts or long-lived plasma cells that are less sensitive to lenalidomide. PMID:27057635

  15. Differential effects of lenalidomide during plasma cell differentiation.

    PubMed

    Jourdan, Michel; Cren, Maïlys; Schafer, Peter; Robert, Nicolas; Duperray, Christophe; Vincent, Laure; Ceballos, Patrice; Cartron, Guillaume; Rossi, Jean-François; Moreaux, Jérôme; Chopra, Rajesh; Klein, Bernard

    2016-05-10

    Thalidomide, lenalidomide and pomalidomide have greatly improved the outcome of patients with multiple myeloma. However, their effects on plasma cells, the healthy counterpart of myeloma cells, are unknown. Here, we investigated lenalidomide effects on normal human plasma cell generation using an in vitro model. Lenalidomide inhibited the generation of pre-plasmablasts and early plasma cells, while it moderately affected plasmablast production. It also reduced the expression level of Ikaros, Aiolos, and IRF4 transcription factors, in plasmablasts and early plasma cells. This suggests that their differential sensitivity to lenalidomide is not due to a difference in Ikaros or Aiolos degradation. Lenalidomide also inhibited long-lived plasma cell generation, but did not impair their long-term survival once generated. This last observation is in agreement with the finding that lenalidomide treatment for 3-18 months did not affect the bone marrow healthy plasma cell count in allografted patients with multiple myeloma. Our findings should prompt to investigate whether lenalidomide resistance in patients with multiple myeloma could be associated with the emergence of malignant plasmablasts or long-lived plasma cells that are less sensitive to lenalidomide.

  16. Differential methylation of genes and repeats in land plants.

    PubMed

    Rabinowicz, Pablo D; Citek, Robert; Budiman, Muhammad A; Nunberg, Andrew; Bedell, Joseph A; Lakey, Nathan; O'Shaughnessy, Andrew L; Nascimento, Lidia U; McCombie, W Richard; Martienssen, Robert A

    2005-10-01

    The hypomethylated fraction of plant genomes is usually enriched in genes and can be selectively cloned using methylation filtration (MF). Therefore, MF has been used as a gene enrichment technology in sorghum and maize, where gene enrichment was proportional to genome size. Here we apply MF to a broad variety of plant species spanning a wide range of genome sizes. Differential methylation of genic and non-genic sequences was observed in all species tested, from non-vascular to vascular plants, but in some cases, such as wheat and pine, a lower than expected level of enrichment was observed. Remarkably, hexaploid wheat and pine show a dramatically large number of gene-like sequences relative to other plants. In hexaploid wheat, this apparent excess of genes may reflect an abundance of methylated pseudogenes, which may thus be more prevalent in recent polyploids.

  17. Induction of differentiation in neoplastic cells.

    PubMed

    Freshney, R I

    1985-01-01

    There is now clear evidence that cells cultured from human and animal tumours can be induced to differentiate in vitro by recognised hormones, regulatory peptides, polar solvents and cytotoxic drugs. Examples can be found from several different types of tumour with the bulk of the data deriving from neuroblastoma and myeloid leukaemia. There is no clear correlation of inducer with cell type, other than some specific peptides like MSH, and agents such as dimethyl sulphoxide and dexamethasone have wide ranging activity. Steroid hormone action may require interaction between different cell types, and the inability of tumours to differentiate in situ may implicate reduced cell-cell interaction, possibly due to degradation of extracellular matrix, or to alteration of the stromal phenotype by tumour-derived factors such as peptides or prostaglandins. When differentiation has been demonstrated, it has been possible, in some cases, to correlate increased differentiation with reduced malignancy by in vitro characterisation or tumorigenicity. Conditions which induce differentiation in rat mammary carcinoma and mouse myeloma also reduce tumour growth in vivo. Clinical trials have not provided any conclusive evidence for a therapeutic benefit so far, but relatively few trials have been carried out. There is clearly a need for further investigation both in vitro and in vivo to select optimal conditions and combinations of agents for clinical evaluation.

  18. Modeling to optimize terminal stem cell differentiation.

    PubMed

    Gallicano, G Ian

    2013-01-01

    Embryonic stem cell (ESC), iPCs, and adult stem cells (ASCs) all are among the most promising potential treatments for heart failure, spinal cord injury, neurodegenerative diseases, and diabetes. However, considerable uncertainty in the production of ESC-derived terminally differentiated cell types has limited the efficiency of their development. To address this uncertainty, we and other investigators have begun to employ a comprehensive statistical model of ESC differentiation for determining the role of intracellular pathways (e.g., STAT3) in ESC differentiation and determination of germ layer fate. The approach discussed here applies the Baysian statistical model to cell/developmental biology combining traditional flow cytometry methodology and specific morphological observations with advanced statistical and probabilistic modeling and experimental design. The final result of this study is a unique tool and model that enhances the understanding of how and when specific cell fates are determined during differentiation. This model provides a guideline for increasing the production efficiency of therapeutically viable ESCs/iPSCs/ASC derived neurons or any other cell type and will eventually lead to advances in stem cell therapy.

  19. Modeling to Optimize Terminal Stem Cell Differentiation

    PubMed Central

    Gallicano, G. Ian

    2013-01-01

    Embryonic stem cell (ESC), iPCs, and adult stem cells (ASCs) all are among the most promising potential treatments for heart failure, spinal cord injury, neurodegenerative diseases, and diabetes. However, considerable uncertainty in the production of ESC-derived terminally differentiated cell types has limited the efficiency of their development. To address this uncertainty, we and other investigators have begun to employ a comprehensive statistical model of ESC differentiation for determining the role of intracellular pathways (e.g., STAT3) in ESC differentiation and determination of germ layer fate. The approach discussed here applies the Baysian statistical model to cell/developmental biology combining traditional flow cytometry methodology and specific morphological observations with advanced statistical and probabilistic modeling and experimental design. The final result of this study is a unique tool and model that enhances the understanding of how and when specific cell fates are determined during differentiation. This model provides a guideline for increasing the production efficiency of therapeutically viable ESCs/iPSCs/ASC derived neurons or any other cell type and will eventually lead to advances in stem cell therapy. PMID:24278782

  20. Regio- and stereoselectivities in plant cell biotransformation

    SciTech Connect

    Hamada, H.

    1995-12-01

    The ability of plant cultured cells to convert foreign substrates into more useful substances is of considerable interest. Therefore I have studied biotransformation of foreign substrate by plant cell suspension cultures. In this presentation, I report regio- and stereoselectivities in biotransformation of steroids and indole alkaloids and taxol by plant (tobacco, periwinkle, moss, orchid) cell suspension cultures.

  1. Regulation of Water in Plant Cells

    ERIC Educational Resources Information Center

    Kowles, Richard V.

    2010-01-01

    Cell water relationships are important topics to be included in cell biology courses. Differences exist in the control of water relationships in plant cells relative to control in animal cells. One important reason for these differences is that turgor pressure is a consideration in plant cells. Diffusion and osmosis are the underlying factors…

  2. Measurement of Total Site Mercury Emissions from Chlor-Alkali Plant Using Ultraviolet Differential Optical Absorption Spectroscopy and Cell Room Roof-Vent Monitoring

    EPA Science Inventory

    This technical note describes a United States Environmental Protection Agency (U.S. EPA) measurement project to determine elemental mercury (Hg0) emissions from a mercury cell chlor-alkali (MCCA) facility in the southeastern U.S. during a 53-day monitoring campaign in the fall of...

  3. Transdifferentiation of adipogenically differentiated cells into osteogenically or chondrogenically differentiated cells: phenotype switching via dedifferentiation.

    PubMed

    Ullah, Mujib; Sittinger, Michael; Ringe, Jochen

    2014-01-01

    Reprogramming is a new wave in cellular therapies to achieve the vital goals of regenerative medicine. Transdifferentiation, whereas the differentiated state of cells could be reprogrammed into other cell types, meaning cells are no more locked in their differentiated circle. Hence, cells of choice from abundant and easily available sources such as fibroblast and adipose tissue could be converted into cells of demand, to restore the diseased tissues. Before diverting this new approach into effective clinical use, transdifferentiation could not be simply overlooked, as it challenges the normal paradigms of biological laws, where mature cells transdifferentiate not only within same germ layers, but even across the lineage boundaries. How unipotent differentiated cells reprogram into another, and whether transdifferentiation proceeds via a direct cell-to-cell conversion or needs dedifferentiation. To address such questions, MSC were adipogenically differentiated followed by direct transdifferentiation, and subsequently examined by histology, immunohistochemistry, qPCR and single cell analysis. Direct cellular conversion of adipogenic lineage cells into osteogenic or chondrogenic resulted in mixed culture of both lineage cells (adipogenic and new acquiring osteogenic/chondrogenic phenotypes). On molecular level, such conversion was confirmed by significantly upregulated expression of PPARG, FABP4, SPP1 and RUNX2. Chondrogenic transdifferentiation was verified by significantly upregulated expression of PPARG, FABP4, SOX9 and COL2A1. Single cell analysis did not support the direct cell-to-cell conversion, rather described the involvement of dedifferentiation. Moreover, some differentiated single cells did not change their phenotype and were resistant to transdifferentiation, suggesting that differentiated cells behave differently during cellular conversion. An obvious characterization of differentiated cells could be helpful to understand the process of

  4. Small Molecule Probes for Plant Cell Wall Polysaccharide Imaging

    PubMed Central

    Wallace, Ian S.; Anderson, Charles T.

    2012-01-01

    Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics. PMID:22639673

  5. Signal transduction and Th17 cell differentiation

    PubMed Central

    O’Shea, John J.; Steward-Tharp, Scott M.; Laurence, Arian; Watford, Wendy T.; Wei, Lai; Adamson, Adewole S.; Fan, Samuel

    2009-01-01

    The paradigm of effector T helper cell differentiation into either Th1 or Th2 lineages has been notably shaken by the discovery of a third lineage of cells that selectively produce interleukin (IL)-17. Characterization of this new subset, referred to as Th17, has provided exciting new insights into immunoregulation, host defense and the pathogenesis of autoimmune diseases. Additionally, the discovery of this T cell subset has offered a fresh look at such concepts as lineage commitment and terminal differentiation. The transcriptional regulatory events and epigenetic modifications that control these processes are diverse and complex, and despite the rapid pace at which data continues to accumulate, many questions remain to be answered. Here we review our current understanding of the signaling pathways, molecular interactions and transcriptional events that lead to Th17 differentiation and effector function, as well as the epigenetic modifications that accompany them. PMID:19379825

  6. Differentiation of ICM cells into trophectoderm.

    PubMed Central

    Pierce, G. B.; Arechaga, J.; Muro, C.; Wells, R. S.

    1988-01-01

    It has been established previously that when inserted in the blastocyst E Ca 247 preferentially differentiates into trophectoderm in vitro. If the concept that tumors are caricatures of the process of tissue renewal is correct, then some cells from the inner cell mass (ICM), the normal counterpart of embryonal carcinoma, should be able to differentiate into trophectoderm. This has been a controversial issue. Four experiments are now reported that support the idea that ICM can differentiate into trophectoderm: 1) ICM from early blastocysts after classical immunosurgery made blastocysts in vitro; 2) ICM obtained from early blastocysts by immunosurgery using antigens other than histocompatibility ones made blastocysts in vitro; 3) ICM from early blastocysts, in which the trophectodermal cells had been labeled, contained no labeled cells following immunosurgery; and 4) In reconstruction experiments, polar and mural trophectodermal cells attached to ICM from late blastocysts failed to multiply and make blastocysts when cultured. It is concluded that like the embryonal carcinoma some ICM cells of early blastocysts have the potential to make trophectoderm. This fact is consistent with the concept that tumors are caricatures of the process of tissue renewal; and establishes E Ca 247 as a good model for study of trophectodermal differentiation. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:3400778

  7. Alternative splicing modulates stem cell differentiation.

    PubMed

    Fu, Ru-Huei; Liu, Shih-Ping; Ou, Chen-Wei; Yu, Hsiu-Hui; Li, Kuo-Wei; Tsai, Chang-Hai; Shyu, Woei-Cherng; Lin, Shinn-Zong

    2009-01-01

    Stem cells have the surprising potential to develop into many different cell types. Therefore, major research efforts have focused on transplantation of stem cells and/or derived progenitors for restoring depleted diseased cells in degenerative disorders. Understanding the molecular controls, including alternative splicing, that arise during lineage differentiation of stem cells is crucial for developing stem cell therapeutic approaches in regeneration medicine. Alternative splicing to allow a single gene to encode multiple transcripts with different protein coding sequences and RNA regulatory elements increases genomic complexities. Utilizing differences in alternative splicing as a molecular marker may be more sensitive than simply gene expression in various degrees of stem cell differentiation. Moreover, alternative splicing maybe provide a new concept to acquire induced pluripotent stem cells or promote cell-cell transdifferentiation for restorative therapies and basic medicine researches. In this review, we highlight the recent advances of alternative splicing regulation in stem cells and their progenitors. It will hopefully provide much needed knowledge into realizing stem cell biology and related applications.

  8. Role of proline in cell wall synthesis and plant development and its implications in plant ontogeny

    PubMed Central

    Kavi Kishor, Polavarapu B.; Hima Kumari, P.; Sunita, M. S. L.; Sreenivasulu, Nese

    2015-01-01

    Proline is a proteogenic amino acid and accumulates both under stress and non-stress conditions as a beneficial solute in plants. Recent discoveries point out that proline plays an important role in plant growth and differentiation across life cycle. It is a key determinant of many cell wall proteins that plays important roles in plant development. The role of extensins, arabinogalactan proteins and hydroxyproline- and proline-rich proteins as important components of cell wall proteins that play pivotal roles in cell wall signal transduction cascades, plant development and stress tolerance is discussed in this review. Molecular insights are also provided here into the plausible roles of proline transporters modulating key events in plant development. In addition, the roles of proline during seed developmental transitions including storage protein synthesis are discussed. PMID:26257754

  9. Selection for niche differentiation in plant communities increases biodiversity effects.

    PubMed

    Zuppinger-Dingley, Debra; Schmid, Bernhard; Petermann, Jana S; Yadav, Varuna; De Deyn, Gerlinde B; Flynn, Dan F B

    2014-11-06

    In experimental plant communities, relationships between biodiversity and ecosystem functioning have been found to strengthen over time, a fact often attributed to increased resource complementarity between species in mixtures and negative plant-soil feedbacks in monocultures. Here we show that selection for niche differentiation between species can drive this increasing biodiversity effect. Growing 12 grassland species in test monocultures and mixtures, we found character displacement between species and increased biodiversity effects when plants had been selected over 8 years in species mixtures rather than in monocultures. When grown in mixtures, relative differences in height and specific leaf area between plant species selected in mixtures (mixture types) were greater than between species selected in monocultures (monoculture types). Furthermore, net biodiversity and complementarity effects were greater in mixtures of mixture types than in mixtures of monoculture types. Our study demonstrates a novel mechanism for the increase in biodiversity effects: selection for increased niche differentiation through character displacement. Selection in diverse mixtures may therefore increase species coexistence and ecosystem functioning in natural communities and may also allow increased mixture yields in agriculture or forestry. However, loss of biodiversity and prolonged selection of crops in monoculture may compromise this potential for selection in the longer term.

  10. Sonic Hedgehog regulates thymic epithelial cell differentiation

    PubMed Central

    Saldaña, José Ignacio; Solanki, Anisha; Lau, Ching-In; Sahni, Hemant; Ross, Susan; Furmanski, Anna L.; Ono, Masahiro; Holländer, Georg; Crompton, Tessa

    2016-01-01

    Sonic Hedgehog (Shh) is expressed in the thymus, where it regulates T cell development. Here we investigated the influence of Shh on thymic epithelial cell (TEC) development. Components of the Hedgehog (Hh) signalling pathway were expressed by TEC, and use of a Gli Binding Site-green fluorescence protein (GFP) transgenic reporter mouse demonstrated active Hh-dependent transcription in TEC in the foetal and adult thymus. Analysis of Shh-deficient foetal thymus organ cultures (FTOC) showed that Shh is required for normal TEC differentiation. Shh-deficient foetal thymus contained fewer TEC than wild type (WT), the proportion of medullary TEC was reduced relative to cortical TEC, and cell surface expression of MHC Class II molecules was increased on both cortical and medullary TEC populations. In contrast, the Gli3-deficient thymus, which shows increased Hh-dependent transcription in thymic stroma, had increased numbers of TEC, but decreased cell surface expression of MHC Class II molecules on both cortical and medullary TEC. Neutralisation of endogenous Hh proteins in WT FTOC led to a reduction in TEC numbers, and in the proportion of mature Aire-expressing medullary TEC, but an increase in cell surface expression of MHC Class II molecules on medullary TEC. Likewise, conditional deletion of Shh from TEC in the adult thymus resulted in alterations in TEC differentiation and consequent changes in T cell development. TEC numbers, and the proportion of mature Aire-expressing medullary TEC were reduced, and cell surface expression of MHC Class II molecules on medullary TEC was increased. Differentiation of mature CD4 and CD8 single positive thymocytes was increased, demonstrating the regulatory role of Shh production by TEC on T cell development. Treatment of human thymus explants with recombinant Shh or neutralising anti-Shh antibody indicated that the Hedgehog pathway is also involved in regulation of differentiation from DP to mature SP T cells in the human thymus. PMID

  11. Sonic Hedgehog regulates thymic epithelial cell differentiation.

    PubMed

    Saldaña, José Ignacio; Solanki, Anisha; Lau, Ching-In; Sahni, Hemant; Ross, Susan; Furmanski, Anna L; Ono, Masahiro; Holländer, Georg; Crompton, Tessa

    2016-04-01

    Sonic Hedgehog (Shh) is expressed in the thymus, where it regulates T cell development. Here we investigated the influence of Shh on thymic epithelial cell (TEC) development. Components of the Hedgehog (Hh) signalling pathway were expressed by TEC, and use of a Gli Binding Site-green fluorescence protein (GFP) transgenic reporter mouse demonstrated active Hh-dependent transcription in TEC in the foetal and adult thymus. Analysis of Shh-deficient foetal thymus organ cultures (FTOC) showed that Shh is required for normal TEC differentiation. Shh-deficient foetal thymus contained fewer TEC than wild type (WT), the proportion of medullary TEC was reduced relative to cortical TEC, and cell surface expression of MHC Class II molecules was increased on both cortical and medullary TEC populations. In contrast, the Gli3-deficient thymus, which shows increased Hh-dependent transcription in thymic stroma, had increased numbers of TEC, but decreased cell surface expression of MHC Class II molecules on both cortical and medullary TEC. Neutralisation of endogenous Hh proteins in WT FTOC led to a reduction in TEC numbers, and in the proportion of mature Aire-expressing medullary TEC, but an increase in cell surface expression of MHC Class II molecules on medullary TEC. Likewise, conditional deletion of Shh from TEC in the adult thymus resulted in alterations in TEC differentiation and consequent changes in T cell development. TEC numbers, and the proportion of mature Aire-expressing medullary TEC were reduced, and cell surface expression of MHC Class II molecules on medullary TEC was increased. Differentiation of mature CD4 and CD8 single positive thymocytes was increased, demonstrating the regulatory role of Shh production by TEC on T cell development. Treatment of human thymus explants with recombinant Shh or neutralising anti-Shh antibody indicated that the Hedgehog pathway is also involved in regulation of differentiation from DP to mature SP T cells in the human thymus.

  12. Stem cell regulation: Implications when differentiated cells regulate symmetric stem cell division.

    PubMed

    Høyem, Marte Rørvik; Måløy, Frode; Jakobsen, Per; Brandsdal, Bjørn Olav

    2015-09-07

    We use a mathematical model to show that if symmetric stem cell division is regulated by differentiated cells, then changes in the population dynamics of the differentiated cells can lead to changes in the population dynamics of the stem cells. More precisely, the relative fitness of the stem cells can be affected by modifying the death rate of the differentiated cells. This result is interesting because stem cells are less sensitive than differentiated cells to environmental factors, such as medical therapy. Our result implies that stem cells can be manipulated indirectly by medical treatments that target the differentiated cells.

  13. Asymptotic phases in a cell differentiation model

    NASA Astrophysics Data System (ADS)

    Friedman, Avner; Kao, Chiu-Yen; Shih, Chih-Wen

    T cells of the immune system, upon maturation, differentiate into either Th1 or Th2 cells that have different functions. The decision to which cell type to differentiate depends on the concentrations of transcription factors T-bet ( x) and GATA-3 ( x). The population density of the T cells, ϕ(t,x,x), satisfies a conservation law ∂ϕ/∂t+(∂/∂x)(fϕ)+(∂/∂x)(fϕ)=gϕ where f depends on (t,x,x) and, in a nonlinear nonlocal way, on ϕ. It is proved that, as t→∞, ϕ(t,x,x) converges to a linear combination of 1, 2, or 4 Dirac measures. Numerical simulations and their biological implications are discussed.

  14. Embryogenic plant cells in microgravity

    NASA Technical Reports Server (NTRS)

    Krikorian, Abraham D.

    1991-01-01

    In view of circumstantial evidence for the role of gravity (g) in shaping the embryo environment, normal embryo development may not occur reliably and efficiently in the microgravity environment of space. Attention must accordingly be given to those aspects of higher plant reproductive biology in space environments required for the production of viable embryos in a 'seed to seed to seed' experiment. It is suggested that cultured cells can be grown to be morphogenetically competent, and can be evaluated as to their ability to simulate embryogenic events usually associated with fertilized eggs in the embryo sac of the ovule in the ovary.

  15. Tcf15 Primes Pluripotent Cells for Differentiation

    PubMed Central

    Davies, Owen R.; Lin, Chia-Yi; Radzisheuskaya, Aliaksandra; Zhou, Xinzhi; Taube, Jessica; Blin, Guillaume; Waterhouse, Anna; Smith, Andrew J.H.; Lowell, Sally

    2013-01-01

    Summary The events that prime pluripotent cells for differentiation are not well understood. Inhibitor of DNA binding/differentiation (Id) proteins, which are inhibitors of basic helix-loop-helix (bHLH) transcription factor activity, contribute to pluripotency by blocking sequential transitions toward differentiation. Using yeast-two-hybrid screens, we have identified Id-regulated transcription factors that are expressed in embryonic stem cells (ESCs). One of these, Tcf15, is also expressed in the embryonic day 4.5 embryo and is specifically associated with a novel subpopulation of primed ESCs. An Id-resistant form of Tcf15 rapidly downregulates Nanog and accelerates somatic lineage commitment. We propose that because Tcf15 can be held in an inactive state through Id activity, it may prime pluripotent cells for entry to somatic lineages upon downregulation of Id. We also find that Tcf15 expression is dependent on fibroblast growth factor (FGF) signaling, providing an explanation for how FGF can prime for differentiation without driving cells out of the pluripotent state. PMID:23395635

  16. Differentiated human stem cells resemble fetal, not adult, β cells.

    PubMed

    Hrvatin, Sinisa; O'Donnell, Charles W; Deng, Francis; Millman, Jeffrey R; Pagliuca, Felicia Walton; DiIorio, Philip; Rezania, Alireza; Gifford, David K; Melton, Douglas A

    2014-02-25

    Human pluripotent stem cells (hPSCs) have the potential to generate any human cell type, and one widely recognized goal is to make pancreatic β cells. To this end, comparisons between differentiated cell types produced in vitro and their in vivo counterparts are essential to validate hPSC-derived cells. Genome-wide transcriptional analysis of sorted insulin-expressing (INS(+)) cells derived from three independent hPSC lines, human fetal pancreata, and adult human islets points to two major conclusions: (i) Different hPSC lines produce highly similar INS(+) cells and (ii) hPSC-derived INS(+) (hPSC-INS(+)) cells more closely resemble human fetal β cells than adult β cells. This study provides a direct comparison of transcriptional programs between pure hPSC-INS(+) cells and true β cells and provides a catalog of genes whose manipulation may convert hPSC-INS(+) cells into functional β cells.

  17. Differential Effect of Plant Lipids on Membrane Organization

    PubMed Central

    Grosjean, Kevin; Mongrand, Sébastien; Beney, Laurent; Simon-Plas, Françoise; Gerbeau-Pissot, Patricia

    2015-01-01

    The high diversity of the plant lipid mixture raises the question of their respective involvement in the definition of membrane organization. This is particularly the case for plant plasma membrane, which is enriched in specific lipids, such as free and conjugated forms of phytosterols and typical phytosphingolipids, such as glycosylinositolphosphoceramides. This question was here addressed extensively by characterizing the order level of membrane from vesicles prepared using various plant lipid mixtures and labeled with an environment-sensitive probe. Fluorescence spectroscopy experiments showed that among major phytosterols, campesterol exhibits a stronger ability than β-sitosterol and stigmasterol to order model membranes. Multispectral confocal microscopy, allowing spatial analysis of membrane organization, demonstrated accordingly the strong ability of campesterol to promote ordered domain formation and to organize their spatial distribution at the membrane surface. Conjugated sterol forms, alone and in synergy with free sterols, exhibit a striking ability to order membrane. Plant sphingolipids, particularly glycosylinositolphosphoceramides, enhanced the sterol-induced ordering effect, emphasizing the formation and increasing the size of sterol-dependent ordered domains. Altogether, our results support a differential involvement of free and conjugated phytosterols in the formation of ordered domains and suggest that the diversity of plant lipids, allowing various local combinations of lipid species, could be a major contributor to membrane organization in particular through the formation of sphingolipid-sterol interacting domains. PMID:25575593

  18. Microfluidic platforms for plant cells studies.

    PubMed

    Sanati Nezhad, A

    2014-09-07

    Conventional methods of plant cell analysis rely on growing plant cells in soil pots or agarose plates, followed by screening the plant phenotypes in traditional greenhouses and growth chambers. These methods are usually costly, need a large number of experiments, suffer from low spatial resolution and disorderly growth behavior of plant cells, with lack of ability to locally and accurately manipulate the plant cells. Microfluidic platforms take advantage of miniaturization for handling small volume of liquids and providing a closed environment, with the purpose of in vitro single cell analysis and characterizing cell response to external cues. These platforms have shown their ability for high-throughput cellular analysis with increased accuracy of experiments, reduced cost and experimental times, versatility in design, ability for large-scale and combinatorial screening, and integration with other miniaturized sensors. Despite extensive research on animal cells within microfluidic environments for high-throughput sorting, manipulation and phenotyping studies, the application of microfluidics for plant cells studies has not been accomplished yet. Novel devices such as RootChip, RootArray, TipChip, and PlantChip developed for plant cells analysis, with high spatial resolution on a micrometer scale mimicking the internal microenvironment of plant cells, offering preliminary results on the capability of microfluidics to conquer the constraints of conventional methods. These devices have been used to study different aspects of plant cell biology such as gene expression, cell biomechanics, cellular mechanism of growth, cell division, and cells fusion. This review emphasizes the advantages of current microfluidic systems for plant science studies, and discusses future prospects of microfluidic platforms for characterizing plant cells response to diverse external cues.

  19. Incidentally detected clear cell renal cell carcinoma with rhabdoid differentiation.

    PubMed

    Krishnamoorthy, Venkatesh; Gowda, Kiran Krishne; Rao, Raman Narayana

    2016-01-01

    Renal cell carcinoma with rhabdoid differentiation (RCC-R) has an aggressive biologic behavior and poor prognosis. A recent consensus statement of the International Society of Urological Pathology (ISUP) proposed a nucleolar grading system (ISUP grade) for RCC to replace Fuhrman system and recommended reporting the presence of rhabdoid differentiation and considering tumors with rhabdoid differentiation to be ISUP Grade 4. We report a case of incidentally detected clear cell RCC-R in a 52-year-old man. This is one of the earliest cases of RCC-R (pT1b) detected and first such case from Indian subcontinent.

  20. Differentiation of Club Cells to Alveolar Epithelial Cells In Vitro

    PubMed Central

    Zheng, Dahai; Soh, Boon-Seng; Yin, Lu; Hu, Guangan; Chen, Qingfeng; Choi, Hyungwon; Han, Jongyoon; Chow, Vincent T. K.; Chen, Jianzhu

    2017-01-01

    Club cells are known to function as regional progenitor cells to repair the bronchiolar epithelium in response to lung damage. By lineage tracing in mice, we have shown recently that club cells also give rise to alveolar type 2 cells (AT2s) and alveolar type 1 cells (AT1s) during the repair of the damaged alveolar epithelium. Here, we show that when highly purified, anatomically and phenotypically confirmed club cells are seeded in 3-dimensional culture either in bulk or individually, they proliferate and differentiate into both AT2- and AT1-like cells and form alveolar-like structures. This differentiation was further confirmed by transcriptomic analysis of freshly isolated club cells and their cultured progeny. Freshly isolated club cells express Sca-1 and integrin α6, markers commonly used to characterize lung stem/progenitor cells. Together, current study for the first time isolated highly purified club cells for in vitro study and demonstrated club cells’ capacity to differentiate into alveolar epithelial cells at the single-cell level. PMID:28128362

  1. Plant Cell Adaptive Responses to Microgravity

    NASA Astrophysics Data System (ADS)

    Kordyum, Elizabeth; Kozeko, Liudmyla; Talalaev, Alexandr

    Microgravity is an abnormal environmental condition that plays no role in the functioning of biosphere. Nevertheless, the chronic effect of microgravity in space flight as an unfamiliar factor does not prevent the development of adaptive reactions at the cellular level. In real microgravity in space flight under the more or less optimal conditions for plant growing, namely temperature, humidity, CO2, light intensity and directivity in the hardware angiosperm plants perform an “reproductive imperative”, i.e. they flower, fruit and yield viable seeds. It is known that cells of a multicellular organism not only take part on reactions of the organism but also carry out processes that maintain their integrity. In light of these principles, the problem of the identification of biochemical, physiological and structural patterns that can have adaptive significance at the cellular and subcellular level in real and simulated microgravity is considered. Cytological studies of plants developing in real and simulated microgravity made it possible to establish that the processes of mitosis, cytokinesis, and tissue differentiation of vegetative and generative organs are largely normal. At the same time, under microgravity, essential reconstruction in the structural and functional organization of cell organelles and cytoskeleton, as well as changes in cell metabolism and homeostasis have been described. In addition, new interesting data concerning the influence of altered gravity on lipid peroxidation intensity, the level of reactive oxygen species, and antioxidant system activity, just like on the level of gene expression and synthesis of low-molecular and high-molecular heat shock proteins were recently obtained. So, altered gravity caused time-dependent increasing of the HSP70 and HSP90 levels in cells, that may indicate temporary strengthening of their functional loads that is necessary for re-establish a new cellular homeostasis. Relative qPCR results showed that

  2. Replication of prions in differentiated muscle cells.

    PubMed

    Herbst, Allen; Aiken, Judd M; McKenzie, Debbie

    2014-01-01

    We have demonstrated that prions accumulate to high levels in non-proliferative C2C12 myotubes. C2C12 cells replicate as myoblasts but can be differentiated into myotubes. Earlier studies indicated that C2C12 myoblasts are not competent for prion replication. (1) We confirmed that observation and demonstrated, for the first time, that while replicative myoblasts do not accumulate PrP(Sc), differentiated post-mitotic myotube cultures replicate prions robustly. Here we extend our observations and describe the implication and utility of this system for replicating prions.

  3. Regulation of cell division in higher plants. Progress report

    SciTech Connect

    Jacobs, T.W.

    1992-07-01

    Cell division is arguably the most fundamental of all developmental processes. In higher plants, mitotic activity is largely confined to foci of patterned cell divisions called meristems. From these perpetually embryonic tissues arise the plant`s essential organs of light capture, support, protection and reproduction. Once an adequate understanding of plant cell mitotic regulation is attained, unprecedented opportunities will ensue for analyzing and genetically controlling diverse aspects of development, including plant architecture, leaf shape, plant height, and root depth. The mitotic cycle in a variety of model eukaryotic systems in under the control of a regulatory network of striking evolutionary conservation. Homologues of the yeast cdc2 gene, its catalytic product, p34, and the cyclin regulatory subunits of the MPF complex have emerged as ubiquitous mitotic regulators. We have cloned cdc2-like and cyclin genes from pea. As in other eukaryotic model systems, p34 of Pisum sativum is a subunit of a high molecular weight complex which binds the fission yeast p13 protein and displays histone H1 kinase activity in vitro. Our primary objective in this study is to gain baseline information about the regulation of this higher plant cell division control complex in non-dividing, differentiated cells as well as in synchronous and asynchronous mitotic cells. We are investigating cdc2 and cyclin expression at the levels of protein abundance, protein phosphorylation and quaternary associations.

  4. Differential white cell count by centrifugal microfluidics.

    SciTech Connect

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  5. Epigenetic Mechanisms Regulating Mesenchymal Stem Cell Differentiation

    PubMed Central

    Pérez-Campo, Flor M.; Riancho, José A.

    2015-01-01

    Human Mesenchymal Stem Cells (hMSCs) have emerged in the last few years as one of the most promising therapeutic cell sources and, in particular, as an important tool for regenerative medicine of skeletal tissues. Although they present a more restricted potency than Embryonic Stem (ES) cells, the use of hMCS in regenerative medicine avoids many of the drawbacks characteristic of ES cells or induced pluripotent stem cells. The challenge in using these cells lies into developing precise protocols for directing cellular differentiation to generate a specific cell lineage. In order to achieve this goal, it is of the upmost importance to be able to control de process of fate decision and lineage commitment. This process requires the coordinate regulation of different molecular layers at transcriptional, posttranscriptional and translational levels. At the transcriptional level, switching on and off different sets of genes is achieved not only through transcriptional regulators, but also through their interplay with epigenetic modifiers. It is now well known that epigenetic changes take place in an orderly way through development and are critical in the determination of lineage-specific differentiation. More importantly, alteration of these epigenetic changes would, in many cases, lead to disease generation and even tumour formation. Therefore, it is crucial to elucidate how epigenetic factors, through their interplay with transcriptional regulators, control lineage commitment in hMSCs. PMID:27019612

  6. Refractive index of plant cell walls

    NASA Technical Reports Server (NTRS)

    Gausman, H. W.; Allen, W. A.; Escobar, D. E.

    1974-01-01

    Air was replaced with media of higher refractive indices by vacuum infiltration in leaves of cucumber, blackeye pea, tomato, and string bean plants, and reflectance of noninfiltrated and infiltrated leaves was spectrophotometrically measured. Infiltrated leaves reflected less light than noninfiltrated leaves over the 500-2500-nm wavelength interval because cell wall-air interfaces were partly eliminated. Minimal reflectance should occur when the average refractive index of plant cell walls was matched by the infiltrating fluid. Although refractive indices that resulted in minimal reflectance differed among the four plant genera, an average value of 1.425 approximates the refractive index of plant cell walls for the four plant genera.

  7. Differential Light Scattering from Spherical Mammalian Cells

    PubMed Central

    Brunsting, Albert; Mullaney, Paul F.

    1974-01-01

    The differential scattered light intensity patterns of spherical mammalian cells were measured with a new photometer which uses high-speed film as the light detector. The scattering objects, interphase and mitotic Chinese hamster ovary cells and HeLa cells, were modeled as (a) a coated sphere, accounting for nucleus and cytoplasm, and (b) a homogeneous sphere when no cellular nucleus was present. The refractive indices and size distribution of the cells were measured for an accurate comparison of the theoretical model with the light-scattering measurements. The light scattered beyond the forward direction is found to contain information about internal cellular morphology, provided the size distribution of the cells is not too broad. ImagesFIGURE 1 PMID:4134589

  8. 21 CFR 864.5220 - Automated differential cell counter.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Automated differential cell counter. 864.5220... § 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell... have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the...

  9. 21 CFR 864.5220 - Automated differential cell counter.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Automated differential cell counter. 864.5220... § 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell... have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the...

  10. 21 CFR 864.5220 - Automated differential cell counter.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Automated differential cell counter. 864.5220... § 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell... have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the...

  11. 21 CFR 864.5220 - Automated differential cell counter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Automated differential cell counter. 864.5220... § 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell... have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the...

  12. 21 CFR 864.5220 - Automated differential cell counter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Automated differential cell counter. 864.5220... § 864.5220 Automated differential cell counter. (a) Identification. An automated differential cell... have the capability to flag, count, or classify immature or abnormal hematopoietic cells of the...

  13. Plant cell walls to ethanol.

    PubMed

    Jordan, Douglas B; Bowman, Michael J; Braker, Jay D; Dien, Bruce S; Hector, Ronald E; Lee, Charles C; Mertens, Jeffrey A; Wagschal, Kurt

    2012-03-01

    Conversion of plant cell walls to ethanol constitutes second generation bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation and separation. Ultimately, it is desirable to combine as many of the biochemical steps as possible in a single organism to achieve CBP (consolidated bioprocessing). A commercially ready CBP organism is currently unreported. Production of second generation bioethanol is hindered by economics, particularly in the cost of pretreatment (including waste management and solvent recovery), the cost of saccharification enzymes (particularly exocellulases and endocellulases displaying kcat ~1 s-1 on crystalline cellulose), and the inefficiency of co-fermentation of 5- and 6-carbon monosaccharides (owing in part to redox cofactor imbalances in Saccharomyces cerevisiae).

  14. Differential radiosensitivity among B cell subpopulations

    SciTech Connect

    Riggs, J.E.; Lussier, A.M.; Lee, S.K.; Appel, M.C.; Woodland, R.T.

    1988-09-15

    We have previously shown that low doses of ionizing radiation selectively impair a functionally defined B cell subpopulation. Normal mice, after exposure to 200 rad of ionizing radiation, have normal or near normal splenic plaque-forming cell responses to thymus-independent type 1 Ag, but reduced responses to thymus-independent type 2 Ag. Here, we confirm and extend the original findings by using hapten-specific serum RIA to demonstrate this differential radiosensitivity is systemic. We also examined splenocytes stained with a panel of lymphocyte surface Ag by FACS analysis to determine if these functional changes are accompanied by a physical alteration of the B cell pool of irradiated mice. Single-parameter FACS analyses demonstrate a diminution in both B cell number and the heterogeneity of membrane Ag expression within the surviving B cell pool after irradiation. In contrast, T cells are relatively radioresistant as the relative percentage of T cells in the irradiated splenocyte pool increases, whereas the heterogeneity of membrane Ag expression remains constant. Multiparameter FACS analyses indicate that B cells with the sIgM much greater than sIgD phenotype are more radiosensitive than B cells of the sIgM much less than sIgD phenotype. In addition, immunohistochemical analysis of splenic sections stained with anti-IgM or anti-IgD reveal the enhanced radiosensitivity of marginal zone B cells.

  15. A Model of Differential Growth-Guided Apical Hook Formation in Plants.

    PubMed

    Žádníková, Petra; Wabnik, Krzysztof; Abuzeineh, Anas; Gallemi, Marçal; Van Der Straeten, Dominique; Smith, Richard S; Inzé, Dirk; Friml, Jiří; Prusinkiewicz, Przemysław; Benková, Eva

    2016-10-01

    Differential cell growth enables flexible organ bending in the presence of environmental signals such as light or gravity. A prominent example of the developmental processes based on differential cell growth is the formation of the apical hook that protects the fragile shoot apical meristem when it breaks through the soil during germination. Here, we combined in silico and in vivo approaches to identify a minimal mechanism producing auxin gradient-guided differential growth during the establishment of the apical hook in the model plant Arabidopsis thaliana Computer simulation models based on experimental data demonstrate that asymmetric expression of the PIN-FORMED auxin efflux carrier at the concave (inner) versus convex (outer) side of the hook suffices to establish an auxin maximum in the epidermis at the concave side of the apical hook. Furthermore, we propose a mechanism that translates this maximum into differential growth, and thus curvature, of the apical hook. Through a combination of experimental and in silico computational approaches, we have identified the individual contributions of differential cell elongation and proliferation to defining the apical hook and reveal the role of auxin-ethylene crosstalk in balancing these two processes.

  16. Mechanical regulation of mesenchymal stem cell differentiation.

    PubMed

    Steward, Andrew J; Kelly, Daniel J

    2015-12-01

    Biophysical cues play a key role in directing the lineage commitment of mesenchymal stem cells or multipotent stromal cells (MSCs), but the mechanotransductive mechanisms at play are still not fully understood. This review article first describes the roles of both substrate mechanics (e.g. stiffness and topography) and extrinsic mechanical cues (e.g. fluid flow, compression, hydrostatic pressure, tension) on the differentiation of MSCs. A specific focus is placed on the role of such factors in regulating the osteogenic, chondrogenic, myogenic and adipogenic differentiation of MSCs. Next, the article focuses on the cellular components, specifically integrins, ion channels, focal adhesions and the cytoskeleton, hypothesized to be involved in MSC mechanotransduction. This review aims to illustrate the strides that have been made in elucidating how MSCs sense and respond to their mechanical environment, and also to identify areas where further research is needed.

  17. Chromatin dynamics during cellular differentiation in the female reproductive lineage of flowering plants

    PubMed Central

    Baroux, Célia; Autran, Daphné

    2015-01-01

    Sexual reproduction in flowering plants offers a number of remarkable aspects to developmental biologists. First, the spore mother cells – precursors of the plant reproductive lineage – are specified late in development, as opposed to precocious germline isolation during embryogenesis in most animals. Second, unlike in most animals where meiosis directly produces gametes, plant meiosis entails the differentiation of a multicellular, haploid gametophyte, within which gametic as well as non-gametic accessory cells are formed. These observations raise the question of the factors inducing and modus operandi of cell fate transitions that originate in floral tissues and gametophytes, respectively. Cell fate transitions in the reproductive lineage imply cellular reprogramming operating at the physiological, cytological and transcriptome level, but also at the chromatin level. A number of observations point to large-scale chromatin reorganization events associated with cellular differentiation of the female spore mother cells and of the female gametes. These include a reorganization of the heterochromatin compartment, the genome-wide alteration of the histone modification landscape, and the remodeling of nucleosome composition. The dynamic expression of DNA methyltransferases and actors of small RNA pathways also suggest additional, global epigenetic alterations that remain to be characterized. Are these events a cause or a consequence of cellular differentiation, and how do they contribute to cell fate transition? Does chromatin dynamics induce competence for immediate cellular functions (meiosis, fertilization), or does it also contribute long-term effects in cellular identity and developmental competence of the reproductive lineage? This review attempts to review these fascinating questions. PMID:26031902

  18. GATA2 regulates dendritic cell differentiation

    PubMed Central

    Onodera, Koichi; Fujiwara, Tohru; Onishi, Yasushi; Itoh-Nakadai, Ari; Okitsu, Yoko; Fukuhara, Noriko; Ishizawa, Kenichi; Shimizu, Ritsuko; Yamamoto, Masayuki

    2016-01-01

    Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin−Sca-1+Kit+ cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte–related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation. PMID:27259979

  19. GATA2 regulates dendritic cell differentiation.

    PubMed

    Onodera, Koichi; Fujiwara, Tohru; Onishi, Yasushi; Itoh-Nakadai, Ari; Okitsu, Yoko; Fukuhara, Noriko; Ishizawa, Kenichi; Shimizu, Ritsuko; Yamamoto, Masayuki; Harigae, Hideo

    2016-07-28

    Dendritic cells (DCs) are critical immune response regulators; however, the mechanism of DC differentiation is not fully understood. Heterozygous germ line GATA2 mutations induce GATA2-deficiency syndrome, characterized by monocytopenia, a predisposition to myelodysplasia/acute myeloid leukemia, and a profoundly reduced DC population, which is associated with increased susceptibility to viral infections, impaired phagocytosis, and decreased cytokine production. To define the role of GATA2 in DC differentiation and function, we studied Gata2 conditional knockout and haploinsufficient mice. Gata2 conditional deficiency significantly reduced the DC count, whereas Gata2 haploinsufficiency did not affect this population. GATA2 was required for the in vitro generation of DCs from Lin(-)Sca-1(+)Kit(+) cells, common myeloid-restricted progenitors, and common dendritic cell precursors, but not common lymphoid-restricted progenitors or granulocyte-macrophage progenitors, suggesting that GATA2 functions in the myeloid pathway of DC differentiation. Moreover, expression profiling demonstrated reduced expression of myeloid-related genes, including mafb, and increased expression of T-lymphocyte-related genes, including Gata3 and Tcf7, in Gata2-deficient DC progenitors. In addition, GATA2 was found to bind an enhancer element 190-kb downstream region of Gata3, and a reporter assay exhibited significantly reduced luciferase activity after adding this enhancer region to the Gata3 promoter, which was recovered by GATA sequence deletion within Gata3 +190. These results suggest that GATA2 plays an important role in cell-fate specification toward the myeloid vs T-lymphocyte lineage by regulating lineage-specific transcription factors in DC progenitors, thereby contributing to DC differentiation.

  20. Plant stem cells as innovation in cosmetics.

    PubMed

    Moruś, Martyna; Baran, Monika; Rost-Roszkowska, Magdalena; Skotnicka-Graca, Urszula

    2014-01-01

    The stem cells thanks to their ability of unlimited division number or transformation into different cell types creating organs, are responsible for regeneration processes. Depending on the organism in which the stem cells exists, they divide to the plant or animal ones. The later group includes the stem cells existing in both embryo's and adult human's organs. It includes, among others, epidermal stem cells, located in the hair follicle relieves and also in its basal layers, and responsible for permanent regeneration of the epidermis. Temporary science looks for method suitable for stimulation of the epidermis stem cells, amongst the other by delivery of e.g., growth factors for proliferation that decrease with the age. One of the methods is the use of the plant cell culture technology, including a number of methods that should ensure growth of plant cells, issues or organs in the environment with the microorganism-free medium. It uses abilities of the different plant cells to dedifferentiation into stem cells and coming back to the pluripotent status. The extracts obtained this way from the plant stem cells are currently used for production of both common or professional care cosmetics. This work describes exactly impact of the plant stem cell extract, coming from one type of the common apple tree (Uttwiler Spätlauber) to human skin as one of the first plant sorts, which are used in cosmetology and esthetic dermatology.

  1. Differentiation of plant age in grasses using remote sensing

    NASA Astrophysics Data System (ADS)

    Knox, Nichola M.; Skidmore, Andrew K.; van der Werff, Harald M. A.; Groen, Thomas A.; de Boer, Willem F.; Prins, Herbert H. T.; Kohi, Edward; Peel, Mike

    2013-10-01

    Phenological or plant age classification across a landscape allows for examination of micro-topographical effects on plant growth, improvement in the accuracy of species discrimination, and will improve our understanding of the spatial variation in plant growth. In this paper six vegetation indices used in phenological studies (including the newly proposed PhIX index) were analysed for their ability to statistically differentiate grasses of different ages in the sequence of their development. Spectra of grasses of different ages were collected from a greenhouse study. These were used to determine if NDVI, NDWI, CAI, EVI, EVI2 and the newly proposed PhIX index could sequentially discriminate grasses of different ages, and subsequently classify grasses into their respective age category. The PhIX index was defined as: (AVNIRn+log(ASWIR2n))/(AVNIRn-log(ASWIR2n)), where AVNIRn and ASWIR2n are the respective normalised areas under the continuum removed reflectance curve within the VNIR (500-800 nm) and SWIR2 (2000-2210 nm) regions. The PhIX index was found to produce the highest phenological classification accuracy (Overall Accuracy: 79%, and Kappa Accuracy: 75%) and similar to the NDVI, EVI and EVI2 indices it statistically sequentially separates out the developmental age classes. Discrimination between seedling and dormant age classes and the adult and flowering classes was problematic for most of the tested indices. Combining information from the visible near infrared (VNIR) and shortwave infrared region (SWIR) region into a single phenological index captures the phenological changes associated with plant pigments and the ligno-cellulose absorption feature, providing a robust method to discriminate the age classes of grasses. This work provides a valuable contribution into mapping spatial variation and monitoring plant growth across savanna and grassland ecosystems.

  2. The epigenomics of embryonic stem cell differentiation.

    PubMed

    Kraushaar, Daniel C; Zhao, Keji

    2013-01-01

    Embryonic stem cells (ESCs) possess an open and highly dynamic chromatin landscape, which underlies their plasticity and ultimately maintains ESC pluripotency. The ESC epigenome must not only maintain the transcription of pluripotency-associated genes but must also, through gene priming, facilitate rapid and cell type-specific activation of developmental genes upon lineage commitment. Trans-generational inheritance ensures that the ESC chromatin state is stably transmitted from one generation to the next; yet at the same time, epigenetic marks are highly dynamic, reversible and responsive to extracellular cues. Once committed to differentiation, the ESC epigenome is remodeled and resolves into a more compact chromatin state. A thorough understanding of the role of chromatin modifiers in ESC fate and differentiation will be important if they are to be used for therapeutic purposes. Recent technical advances, particularly in next-generation sequencing technologies, have provided a genome-scale view of epigenetic marks and chromatin modifiers. More affordable and faster sequencing platforms have led to a comprehensive characterization of the ESC epigenome and epigenomes of differentiated cell types. In this review, we summarize and discuss the recent progress that has highlighted the central role of histone modifications, histone variants, DNA methylation and chromatin modifiers in ESC pluripotency and ESC fate. We provide a detailed and comprehensive discussion of genome-wide studies that are pertinent to our understanding of mammalian development.

  3. Molecular mechanisms of male germ cell differentiation.

    PubMed

    Hecht, N B

    1998-07-01

    During spermatogenesis, diploid stem cells differentiate, undergo meiosis, and transform into haploid spermatozoa. As this precisely timed series of events proceeds, chromosomal ploidy is reduced and the nucleosomes of the chromatin are replaced by a transcriptionally quiescent protamine-containing nucleus. The premature termination of transcription during the haploid phase of spermatogenesis necessitates an especially prominent role for posttranscriptional regulation in the temporal and spatial expression of many testis-specific proteins and isozymes. In this review article, discussion will focus on novel mechanisms regulating gene expression in mammalian male germ cells from genome to protein.

  4. [On plant stem cells and animal stem cells].

    PubMed

    You, Yun; Jiang, Chao; Huang, Lu-Qi

    2014-01-01

    A comparison of plant and animal stem cells can highlight core aspects of stem-cell biology. In both kingdoms, stem cells are defined by their clonogenic properties and are maintained by intercellular signals. The signaling molecules are different in plants and animals stem cell niches, but the roles of argonaute and polycomb group proteins suggest that there are some molecular similarities.

  5. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    SciTech Connect

    Darvill, Alan; Hahn, Michael G.; O'Neill, Malcolm A.; York, William S.

    2015-02-17

    Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

  6. Gravity, chromosomes, and organized development in aseptically cultured plant cells

    NASA Technical Reports Server (NTRS)

    Krikorian, Abraham D.

    1993-01-01

    The objectives of the PCR experiment are: to test the hypothesis that microgravity will in fact affect the pattern and developmental progression of embryogenically competent plant cells from one well-defined, critical stage to another; to determine the effects of microgravity in growth and differentiation of embryogenic carrot cells grown in cell culture; to determine whether microgravity or the space environment fosters an instability of the differentiated state; and to determine whether mitosis and chromosome behavior are adversely affected by microgravity. The methods employed will consist of the following: special embryogenically competent carrot cell cultures will be grown in cell culture chambers provided by NASDA; four cell culture chambers will be used to grow cells in liquid medium; two dishes (plant cell culture dishes) will be used to grow cells on a semi-solid agar support; progression to later embryonic stages will be induced in space via crew intervention and by media manipulation in the case of liquid grown cell cultures; progression to later stages in case of semi-solid cultures will not need crew intervention; embryo stages will be fixed at a specific interval (day 6) in flight only in the case of liquid-grown cultures; and some living cells and somatic embryos will be returned for continued post-flight development and 'grown-out.' These will derive from the semi-solid grown cultures.

  7. [Genetic regulation of plant shoot stem cells].

    PubMed

    Al'bert, E V; Ezhova, T A

    2013-02-01

    This article describes the main features of plant stem cells and summarizes the results of studies of the genetic control of stem cell maintenance in the apical meristem of the shoot. It is demonstrated that the WUS-CLV gene system plays a key role in the maintenance of shoot apical stem cells and the formation of adventitious buds and somatic embryos. Unconventional concepts of plant stem cells are considered.

  8. Polarity establishment, morphogenesis, and cultured plant cells in space

    NASA Technical Reports Server (NTRS)

    Krikorian, Abraham D.

    1989-01-01

    Plant development entails an orderly progression of cellular events both in terms of time and geometry. There is only circumstantial evidence that, in the controlled environment of the higher plant embryo sac, gravity may play a role in embryo development. It is still not known whether or not normal embryo development and differentiation in higher plants can be expected to take place reliably and efficiently in the micro g space environment. It seems essential that more attention be given to studying aspects of reproductive biology in order to be confident that plants will survive seed to seed to seed in a space environment. Until the time arrives when successive generations of plants can be grown, the best that can be done is utilize the most appropriate systems and begin, piece meal, to accumulate information on important aspects of plant reproduction. Cultured plant cells can play an important role in these activities since they can be grown so as to be morphogenetically competent, and thus can simulate those embryogenic events more usually identified with fertilized eggs in the embryo sac of the ovule in the ovary. Also, they can be manipulated with relative ease. The extreme plasticity of such demonstrably totipotent cell systems provides a means to test environmental effects such as micro g on a potentially free-running entity. The successful manipulation and management of plant cells and propagules in space also has significance for exploitation of biotechnologies in space since such systems, perforce, are an important vehicle whereby many genetic engineering manipulations are achieved.

  9. Cell-to-cell communication in plants, animals, and fungi: a comparative review

    NASA Astrophysics Data System (ADS)

    Bloemendal, Sandra; Kück, Ulrich

    2013-01-01

    Cell-to-cell communication is a prerequisite for differentiation and development in multicellular organisms. This communication has to be tightly regulated to ensure that cellular components such as organelles, macromolecules, hormones, or viruses leave the cell in a precisely organized way. During evolution, plants, animals, and fungi have developed similar ways of responding to this biological challenge. For example, in higher plants, plasmodesmata connect adjacent cells and allow communication to regulate differentiation and development. In animals, two main general structures that enable short- and long-range intercellular communication are known, namely gap junctions and tunneling nanotubes, respectively. Finally, filamentous fungi have also developed specialized structures called septal pores that allow intercellular communication via cytoplasmic flow. This review summarizes the underlying mechanisms for intercellular communication in these three eukaryotic groups and discusses its consequences for the regulation of differentiation and developmental processes.

  10. Pathological modifications of plant stem cell destiny

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In higher plants, the shoot apex contains undifferentiated stem cells that give rise to various tissues and organs. The fate of these stem cells determines the pattern of plant growth as well as reproduction; and such fate is genetically preprogrammed. We found that a bacterial infection can derai...

  11. Cell fusion and nuclear fusion in plants.

    PubMed

    Maruyama, Daisuke; Ohtsu, Mina; Higashiyama, Tetsuya

    2016-12-01

    Eukaryotic cells are surrounded by a plasma membrane and have a large nucleus containing the genomic DNA, which is enclosed by a nuclear envelope consisting of the outer and inner nuclear membranes. Although these membranes maintain the identity of cells, they sometimes fuse to each other, such as to produce a zygote during sexual reproduction or to give rise to other characteristically polyploid tissues. Recent studies have demonstrated that the mechanisms of plasma membrane or nuclear membrane fusion in plants are shared to some extent with those of yeasts and animals, despite the unique features of plant cells including thick cell walls and intercellular connections. Here, we summarize the key factors in the fusion of these membranes during plant reproduction, and also focus on "non-gametic cell fusion," which was thought to be rare in plant tissue, in which each cell is separated by a cell wall.

  12. Epigenetic inheritance of cell differentiation status.

    PubMed

    Ng, Ray K; Gurdon, John B

    2008-05-01

    Epigenetic modifications influence gene expression pattern and provide a unique signature of a cell differentiation status. Without external stimuli or signalling events, this cell identity remains stable and unlikely to change over many cell divisions. The epigenetic signature of a particular cell fate therefore needs to be replicated faithfully in daughter cells; otherwise a cell lineage cannot be maintained. However, the mechanism of transmission of cellular memory from mother to daughter cells remains unclear. It has been suggested that the inheritance of an active or silent gene state involves different kinds of epigenetic mechanisms, e.g. DNA methylation, histone modifications, replacement of histone variants, Polycomb group (PcG) and Trithorax group (TrxG) proteins. Emerging evidence supports the role of histone variant H3.3 in maintaining an active gene status and in remodelling nucleosomal composition. Here we discuss some recent findings on the propagation of epigenetic memory and propose a model for the inheritance of an active gene state through the interaction of H3.3 with other epigenetic components.

  13. Plant Response to Differential Soil Water Content and Salinity

    NASA Astrophysics Data System (ADS)

    Moradi, A. B.; Dara, A.; Kamai, T.; Ngo, A.; Walker, R.; Hopmans, J. W.

    2011-12-01

    Root-zone soil water content is extremely dynamic, governed by complex and coupled processes such as root uptake, irrigation, evaporation, and leaching. Root uptake of water and nutrients is influenced by these conditions and the processes involved. Plant roots are living and functioning in a dynamic environment that is subjected to extreme changes over relatively short time and small distances. In order to better manage our agricultural resources and cope with increasing constraints of water limitation, environmental concerns and climate change, it is vital to understand plants responses to these changes in their environment. We grew chick pea (Cicer arietinum) plants, in boxes of 30 x 25 x 1 cm dimensions filled with fine sand. Layers of coarse sand (1.5 cm thick) were embedded in the fine-sand media to divide the root growth environment into sections that were hydraulically disconnected from each other. This way, each section could be independently treated with differential levels of water and salinity. The root growth and distribution in the soil was monitored on daily bases using neutron radiography. Daily water uptake was measured by weighing the containers. Changes of soil water content in each section of the containers were calculated from the neutron radiographs. Plants that part of their root system was stressed with drought or salinity showed no change in their daily water uptake rate. The roots in the stressed sections stayed turgid during the stress period and looked healthy in the neutron images. However the uptake rate was severely affected when the soil in the non-stressed section started to dry. The plants were then fully irrigated with water and the water uptake rate recovered to its initial rate shortly after irrigation. The neutron radiographs clearly illustrated the shrinkage and recovery of the roots under stress and the subsequent relief. This cycle was repeated a few times and the same trend could be reproduced. Our results show that plants

  14. The cell biology of lignification in higher plants

    PubMed Central

    Barros, Jaime; Serk, Henrik; Granlund, Irene; Pesquet, Edouard

    2015-01-01

    Background Lignin is a polyphenolic polymer that strengthens and waterproofs the cell wall of specialized plant cell types. Lignification is part of the normal differentiation programme and functioning of specific cell types, but can also be triggered as a response to various biotic and abiotic stresses in cells that would not otherwise be lignifying. Scope Cell wall lignification exhibits specific characteristics depending on the cell type being considered. These characteristics include the timing of lignification during cell differentiation, the palette of associated enzymes and substrates, the sub-cellular deposition sites, the monomeric composition and the cellular autonomy for lignin monomer production. This review provides an overview of the current understanding of lignin biosynthesis and polymerization at the cell biology level. Conclusions The lignification process ranges from full autonomy to complete co-operation depending on the cell type. The different roles of lignin for the function of each specific plant cell type are clearly illustrated by the multiple phenotypic defects exhibited by knock-out mutants in lignin synthesis, which may explain why no general mechanism for lignification has yet been defined. The range of phenotypic effects observed include altered xylem sap transport, loss of mechanical support, reduced seed protection and dispersion, and/or increased pest and disease susceptibility. PMID:25878140

  15. A quantitative and dynamic model for plant stem cell regulation.

    PubMed

    Geier, Florian; Lohmann, Jan U; Gerstung, Moritz; Maier, Annette T; Timmer, Jens; Fleck, Christian

    2008-01-01

    Plants maintain pools of totipotent stem cells throughout their entire life. These stem cells are embedded within specialized tissues called meristems, which form the growing points of the organism. The shoot apical meristem of the reference plant Arabidopsis thaliana is subdivided into several distinct domains, which execute diverse biological functions, such as tissue organization, cell-proliferation and differentiation. The number of cells required for growth and organ formation changes over the course of a plants life, while the structure of the meristem remains remarkably constant. Thus, regulatory systems must be in place, which allow for an adaptation of cell proliferation within the shoot apical meristem, while maintaining the organization at the tissue level. To advance our understanding of this dynamic tissue behavior, we measured domain sizes as well as cell division rates of the shoot apical meristem under various environmental conditions, which cause adaptations in meristem size. Based on our results we developed a mathematical model to explain the observed changes by a cell pool size dependent regulation of cell proliferation and differentiation, which is able to correctly predict CLV3 and WUS over-expression phenotypes. While the model shows stem cell homeostasis under constant growth conditions, it predicts a variation in stem cell number under changing conditions. Consistent with our experimental data this behavior is correlated with variations in cell proliferation. Therefore, we investigate different signaling mechanisms, which could stabilize stem cell number despite variations in cell proliferation. Our results shed light onto the dynamic constraints of stem cell pool maintenance in the shoot apical meristem of Arabidopsis in different environmental conditions and developmental states.

  16. Differentiation-stimulating potency of differentiated HL60 cells after drug treatment.

    PubMed

    Wang, Cong; Zhang, Qun; Gou, Bao-Di; Zhang, Tian-Lan; Wang, Kui

    2014-06-01

    Differentiation therapy in the treatment of leukemia is often hampered by limitations on using certain pharmaceutical regents or on the required doses due to various reasons, such as drug-resistance and retinoic acid syndrome. To circumvent these problems, a strategy might be developed on the basis of the ability of drug-differentiated cells to stimulate differentiation in leukemia cells. Using the promyelocytic leukemia cell line HL60 as a cell model, we assessed the differentiation-stimulating potency of differentiated granulocytes and monocytes/macrophages after treatments with all-trans retinoic acid (ATRA) and 12-O-tetradecanoylphorbol-13-acetate (TPA), respectively. ATRA- and TPA-differentiated cells were able to stimulate differentiation in fresh HL60 cells, accompanied by inhibition on cell growth to various extents. The differentiated cells of the second generation, especially those originated from TPA treatment, were as potent as the drugs themselves in stimulating differentiation in fresh HL60 cells. On the basis of "differentiation induced by differentiated cells", we explored the feasibility of ex vivo therapy.

  17. Piper and Vismia species from Colombian Amazonia differentially affect cell proliferation of hepatocarcinoma cells.

    PubMed

    Lizcano, Leandro J; Siles, Maite; Trepiana, Jenifer; Hernández, M Luisa; Navarro, Rosaura; Ruiz-Larrea, M Begoña; Ruiz-Sanz, José Ignacio

    2014-12-30

    There is an increasing interest to identify plant-derived natural products with antitumor activities. In this work, we have studied the effects of aqueous leaf extracts from Amazonian Vismia and Piper species on human hepatocarcinoma cell toxicity. Results showed that, depending on the cell type, the plants displayed differential effects; thus, Vismia baccifera induced the selective killing of HepG2, while increasing cell growth of PLC-PRF and SK-HEP-1. In contrast, these two last cell lines were sensitive to the toxicity by Piper krukoffii and Piper putumayoense, while the Piperaceae did not affect HepG2 growth. All the extracts induced cytotoxicity to rat hepatoma McA-RH7777, but were innocuous (V. baccifera at concentrations < 75 µg/mL) or even protected cells from basal death (P. putumayoense) in primary cultures of rat hepatocytes. In every case, cytotoxicity was accompanied by an intracellular accumulation of reactive oxygen species (ROS). These results provide evidence for the anticancer activities of the studied plants on specific cell lines and suggest that cell killing could be mediated by ROS, thus involving mechanisms independent of the plants free radical scavenging activities. Results also support the use of these extracts of the Vismia and Piper genera with opposite effects as a model system to study the mechanisms of the antitumoral activity against different types of hepatocarcinoma.

  18. Cell wall, cytoskeleton, and cell expansion in higher plants.

    PubMed

    Bashline, Logan; Lei, Lei; Li, Shundai; Gu, Ying

    2014-04-01

    To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.

  19. Probing stem cell differentiation using atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Liang, Xiaobin; Shi, Xuetao; Ostrovidov, Serge; Wu, Hongkai; Nakajima, Ken

    2016-03-01

    A real-time method using atomic force microscopy (AFM) was developed to probe stem cell differentiation by measuring the mechanical properties of cells and the extracellular matrix (ECM). The mechanical properties of stem cells and their ECMs can be used to clearly distinguish specific stem cell-differentiated lineages. It is clear that AFM is a facile and useful tool for monitoring the differentiation of stem cells in a non-invasive manner.

  20. Control of male germ-cell development in flowering plants.

    PubMed

    Singh, Mohan B; Bhalla, Prem L

    2007-11-01

    Plant reproduction is vital for species survival, and is also central to the production of food for human consumption. Seeds result from the successful fertilization of male and female gametes, but our understanding of the development, differentiation of gamete lineages and fertilization processes in higher plants is limited. Germ cells in animals diverge from somatic cells early in embryo development, whereas plants have distinct vegetative and reproductive phases in which gametes are formed from somatic cells after the plant has made the transition to flowering and the formation of the reproductive organs. Recently, novel insights into the molecular mechanisms underlying male germ-line initiation and male gamete development in plants have been obtained. Transcriptional repression of male germ-line genes in non-male germ-line cells have been identified as a key mechanism for spatial and temporal control of male germ-line development. This review focuses on molecular events controlling male germ-line development especially, on the nature and regulation of gene expression programs operating in male gametes of flowering plants.

  1. Plant cell proliferation inside an inorganic host.

    PubMed

    Perullini, Mercedes; Rivero, María Mercedes; Jobbágy, Matías; Mentaberry, Alejandro; Bilmes, Sara A

    2007-01-10

    In recent years, much attention has been paid to plant cell culture as a tool for the production of secondary metabolites and the expression of recombinant proteins. Plant cell immobilization offers many advantages for biotechnological processes. However, the most extended matrices employed, such as calcium-alginate, cannot fully protect entrapped cells. Sol-gel chemistry of silicates has emerged as an outstanding strategy to obtain biomaterials in which living cells are truly protected. This field of research is rapidly developing and a large number of bacteria and yeast-entrapping ceramics have already been designed for different applications. But even mild thermal and chemical conditions employed in sol-gel synthesis may result harmful to cells of higher organisms. Here we present a method for the immobilization of plant cells that allows cell growth at cavities created inside a silica matrix. Plant cell proliferation was monitored for a 6-month period, at the end of which plant calli of more than 1 mm in diameter were observed inside the inorganic host. The resulting hybrid device had good mechanical stability and proved to be an effective barrier against biological contamination, suggesting that it could be employed for long-term plant cell entrapment applications.

  2. Smooth muscle differentiation in scleroderma fibroblastic cells.

    PubMed Central

    Sappino, A. P.; Masouyé, I.; Saurat, J. H.; Gabbiani, G.

    1990-01-01

    Using antibodies to alpha-smooth muscle actin and desmin on paraffin-embedded formalin-fixed tissue sections, the authors demonstrate that fibroblastic cells of localized and systemic scleroderma lesions express features of smooth muscle differentiation. Eleven of eleven skin specimens of systemic sclerosis patients and two of four skin specimens of localized scleroderma displayed the presence of fibroblasts expressing alpha-smooth muscle actin, a cell population that predominated in areas of prominent collagen deposition. A similar fibroblastic phenotype was found in the esophagus, the liver, and the lung specimens obtained from four patients who died of progressive systemic sclerosis. Immunostaining for desmin, performed on adjacent tissue sections, demonstrated that a minority of these fibroblastic cells present in skin and visceral lesions contained this protein. The authors' observations indicate that scleroderma fibroblasts are phenotypically related to the stromal cells previously identified in hypertrophic scars, fibromatoses, and desmoplasia; they might provide novel criteria for the characterization of scleroderma lesions and help to identify the factors responsible for phenotypic modulations in fibroblastic cells. Images Figure 1 Figure 2 Figure 3 PMID:1698026

  3. Neuronal Differentiation of Human Mesenchymal Stem Cells Using Exosomes Derived from Differentiating Neuronal Cells

    PubMed Central

    Takeda, Yuji S.; Xu, Qiaobing

    2015-01-01

    Exosomes deliver functional proteins and genetic materials to neighboring cells, and have potential applications for tissue regeneration. One possible mechanism of exosome-promoted tissue regeneration is through the delivery of microRNA (miRNA). In this study, we hypothesized that exosomes derived from neuronal progenitor cells contain miRNAs that promote neuronal differentiation. We treated mesenchymal stem cells (MSCs) daily with exosomes derived from PC12 cells, a neuronal cell line, for 1 week. After the treatment with PC12-derived exosomes, MSCs developed neuron-like morphology, and gene and protein expressions of neuronal markers were upregulated. Microarray analysis showed that the expression of miR-125b, which is known to play a role in neuronal differentiation of stem cells, was much higher in PC12-derived exosomes than in exosomes from B16-F10 melanoma cells. These results suggest that the delivery of miRNAs contained in PC12-derived exosomes is a possible mechanism explaining the neuronal differentiation of MSC. PMID:26248331

  4. Directed differentiation of pluripotent stem cells to kidney cells.

    PubMed

    Lam, Albert Q; Freedman, Benjamin S; Bonventre, Joseph V

    2014-07-01

    Regenerative medicine affords a promising therapeutic strategy for the treatment of patients with chronic kidney disease. Nephron progenitor cell populations exist only during embryonic kidney development. Understanding the mechanisms by which these populations arise and differentiate is integral to the challenge of generating new nephrons for therapeutic purposes. Pluripotent stem cells (PSCs), comprising embryonic stem cells, and induced pluripotent stem cells (iPSCs) derived from adults, have the potential to generate functional kidney cells and tissue. Studies in mouse and human PSCs have identified specific approaches to the addition of growth factors, including Wnt and fibroblast growth factor, that can induce PSC differentiation into cells with phenotypic characteristics of nephron progenitor populations with the capacity to form kidney-like structures. Although significant progress has been made, further studies are necessary to confirm the production of functional kidney cells and to promote their three-dimensional organization into bona fide kidney tissue. Human PSCs have been generated from patients with kidney diseases, including polycystic kidney disease, Alport syndrome, and Wilms tumor, and may be used to better understand phenotypic consequences of naturally occurring genetic mutations and to conduct "clinical trials in a dish". The capability to generate human kidney cells from PSCs has significant translational applications, including the bioengineering of functional kidney tissue, use in drug development to test compounds for efficacy and toxicity, and in vitro disease modeling.

  5. Soft matrix supports osteogenic differentiation of human dental follicle cells

    SciTech Connect

    Viale-Bouroncle, Sandra; Voellner, Florian; Moehl, Christoph; Kuepper, Kevin; Brockhoff, Gero; Reichert, Torsten E.; Schmalz, Gottfried; Morsczeck, Christian

    2011-07-08

    Highlights: {yields} Rigid stiffness supports osteogenic differentiation in mesenchymal stem cells (MSCs). {yields} Our study examined stiffness and differentiation of dental follicle cells (DFCs). {yields} Soft ECMs have a superior capacity to support the osteogenic differentiation of DFCs. {yields} DFCs and MSCs react contrarily to soft and rigid surface stiffness. -- Abstract: The differentiation of stem cells can be directed by the grade of stiffness of the developed tissue cells. For example a rigid extracellular matrix supports the osteogenic differentiation in bone marrow derived mesenchymal stem cells (MSCs). However, less is known about the relation of extracellular matrix stiffness and cell differentiation of ectomesenchymal dental precursor cells. Our study examined for the first time the influence of the surface stiffness on the proliferation and osteogenic differentiation of human dental follicle cells (DFCs). Cell proliferation of DFCs was only slightly decreased on cell culture surfaces with a bone-like stiffness. The osteogenic differentiation in DFCs could only be initiated with a dexamethasone based differentiation medium after using varying stiffness. Here, the softest surface improved the induction of osteogenic differentiation in comparison to that with the highest stiffness. In conclusion, different to bone marrow derived MSCs, soft ECMs have a superior capacity to support the osteogenic differentiation of DFCs.

  6. Ependymal cell differentiation, from monociliated to multiciliated cells.

    PubMed

    Delgehyr, Nathalie; Meunier, Alice; Faucourt, Marion; Bosch Grau, Montserrat; Strehl, Laetitia; Janke, Carsten; Spassky, Nathalie

    2015-01-01

    Primary and motile cilia differ in their structure, composition, and function. In the brain, primary cilia are immotile signalling organelles present on neural stem cells and neurons. Multiple motile cilia are found on the surface of ependymal cells in all brain ventricles, where they contribute to the flow of cerebrospinal fluid. During development, monociliated ependymal progenitor cells differentiate into multiciliated ependymal cells, thus providing a simple system for studying the transition between these two stages. In this chapter, we provide protocols for immunofluorescence staining of developing ependymal cells in vivo, on whole mounts of lateral ventricle walls, and in vitro, on cultured ependymal cells. We also provide a list of markers we currently use to stain both types of cilia, including proteins at the ciliary membrane and tubulin posttranslational modifications of the axoneme.

  7. Bam and Bgcn in Drosophila germline stem cell differentiation.

    PubMed

    Perinthottathil, Sreejith; Kim, Changsoo

    2011-01-01

    The female Drosophila reproductive organ, the ovary, has provided researchers with an incisive genetic system with which principle regulation of stem cell maintenance and differentiation has been delineated. An environmental niche regulates a stem cell's asymmetric self-renewal division that produces a daughter stem cell and a differentiated daughter cell, which further differentiate into eggs. A number of extrinsic and intrinsic factors have been identified that are required either for stem cell maintenance or differentiation. Bam/Bgcn complex plays a pivotal role in promoting stem cell differentiation. Recent papers suggest that Bam/Bgcn complex regulates translation of important maintenance factors and is also involved in the regulation of microRNA-dependent translational repression. Here, we focus on Bam and Bgcn repression of stem cell maintenance factors in the differentiation of germline stem cells (GSCs).

  8. Stochasticity and Spatial Interaction Govern Stem Cell Differentiation Dynamics

    NASA Astrophysics Data System (ADS)

    Smith, Quinton; Stukalin, Evgeny; Kusuma, Sravanti; Gerecht, Sharon; Sun, Sean X.

    2015-07-01

    Stem cell differentiation underlies many fundamental processes such as development, tissue growth and regeneration, as well as disease progression. Understanding how stem cell differentiation is controlled in mixed cell populations is an important step in developing quantitative models of cell population dynamics. Here we focus on quantifying the role of cell-cell interactions in determining stem cell fate. Toward this, we monitor stem cell differentiation in adherent cultures on micropatterns and collect statistical cell fate data. Results show high cell fate variability and a bimodal probability distribution of stem cell fraction on small (80-140 μm diameter) micropatterns. On larger (225-500 μm diameter) micropatterns, the variability is also high but the distribution of the stem cell fraction becomes unimodal. Using a stochastic model, we analyze the differentiation dynamics and quantitatively determine the differentiation probability as a function of stem cell fraction. Results indicate that stem cells can interact and sense cellular composition in their immediate neighborhood and adjust their differentiation probability accordingly. Blocking epithelial cadherin (E-cadherin) can diminish this cell-cell contact mediated sensing. For larger micropatterns, cell motility adds a spatial dimension to the picture. Taken together, we find stochasticity and cell-cell interactions are important factors in determining cell fate in mixed cell populations.

  9. Nuclear receptor regulation of stemness and stem cell differentiation

    PubMed Central

    Jeong, Yangsik

    2009-01-01

    Stem cells include a diverse number of toti-, pluri-, and multi-potent cells that play important roles in cellular genesis and differentiation, tissue development, and organogenesis. Genetic regulation involving various transcription factors results in the self-renewal and differentiation properties of stem cells. The nuclear receptor (NR) superfamily is composed of 48 ligand-activated transcription factors involved in diverse physiological functions such as metabolism, development, and reproduction. Increasing evidence shows that certain NRs function in regulating stemness or differentiation of embryonic stem (ES) cells and tissue-specific adult stem cells. Here, we review the role of the NR superfamily in various aspects of stem cell biology, including their regulation of stemness, forward- and trans-differentiation events; reprogramming of terminally differentiated cells; and interspecies differences. These studies provide insights into the therapeutic potential of the NR superfamily in stem cell therapy and in treating stem cell-associated diseases (e.g., cancer stem cell). PMID:19696553

  10. Plant cells use auxin efflux to explore geometry.

    PubMed

    Zaban, Beatrix; Liu, Wenwen; Jiang, Xingyu; Nick, Peter

    2014-07-28

    Cell movement is the central mechanism for animal morphogenesis. Plant cell development rather relies on flexible alignment of cell axis adjusting cellular differentiation to directional cues. As central input, vectorial fields of mechanical stress and gradients of the phytohormone auxin have been discussed. In tissue contexts, mechanical and chemical signals will always act in concert; experimentally it is difficult to dissect their individual roles. We have designed a novel approach, based on cells, where directionality has been eliminated by removal of the cell wall. We impose a new axis using a microfluidic set-up to generate auxin gradients. Rectangular microvessels are integrated orthogonally with the gradient. Cells in these microvessels align their new axis with microvessel geometry before touching the wall. Auxin efflux is necessary for this touch-independent geometry exploration and we suggest a model, where auxin gradients can be used to align cell axis in tissues with minimized mechanical tensions.

  11. Plant Cells Use Auxin Efflux to Explore Geometry

    PubMed Central

    Zaban, Beatrix; Liu, Wenwen; Jiang, Xingyu; Nick, Peter

    2014-01-01

    Cell movement is the central mechanism for animal morphogenesis. Plant cell development rather relies on flexible alignment of cell axis adjusting cellular differentiation to directional cues. As central input, vectorial fields of mechanical stress and gradients of the phytohormone auxin have been discussed. In tissue contexts, mechanical and chemical signals will always act in concert; experimentally it is difficult to dissect their individual roles. We have designed a novel approach, based on cells, where directionality has been eliminated by removal of the cell wall. We impose a new axis using a microfluidic set-up to generate auxin gradients. Rectangular microvessels are integrated orthogonally with the gradient. Cells in these microvessels align their new axis with microvessel geometry before touching the wall. Auxin efflux is necessary for this touch-independent geometry exploration and we suggest a model, where auxin gradients can be used to align cell axis in tissues with minimized mechanical tensions. PMID:25068254

  12. Bestatin inhibits cell growth, cell division, and spore cell differentiation in Dictyostelium discoideum.

    PubMed

    Poloz, Yekaterina; Catalano, Andrew; O'Day, Danton H

    2012-04-01

    Bestatin methyl ester (BME) is an inhibitor of Zn(2+)-binding aminopeptidases that inhibits cell proliferation and induces apoptosis in normal and cancer cells. We have used Dictyostelium as a model organism to study the effects of BME. Only two Zn(2+)-binding aminopeptidases have been identified in Dictyostelium to date, puromycin-sensitive aminopeptidase A and B (PsaA and PsaB). PSA from other organisms is known to regulate cell division and differentiation. Here we show that PsaA is differentially expressed throughout growth and development of Dictyostelium, and its expression is regulated by developmental morphogens. We present evidence that BME specifically interacts with PsaA and inhibits its aminopeptidase activity. Treatment of cells with BME inhibited the rate of cell growth and the frequency of cell division in growing cells and inhibited spore cell differentiation during late development. Overexpression of PsaA-GFP (where GFP is green fluorescent protein) also inhibited spore cell differentiation but did not affect growth. Using chimeras, we have identified that nuclear versus cytoplasmic localization of PsaA affects the choice between stalk or spore cell differentiation pathway. Cells that overexpressed PsaA-GFP (primarily nuclear) differentiated into stalk cells, while cells that overexpressed PsaAΔNLS2-GFP (cytoplasmic) differentiated into spores. In conclusion, we have identified that BME inhibits cell growth, division, and differentiation in Dictyostelium likely through inhibition of PsaA.

  13. Identifying microRNAs that Regulate Neuroblastoma Cell Differentiation

    DTIC Science & Technology

    2015-10-01

    Award Number: W81XWH-13-1-0241 TITLE: Identifying that Regulate Neuroblastoma Cell Differentiation PRINCIPAL INVESTIGATOR: Dr. Liqin Du...inducing miRNA, miR- 449a. We examined the differentiation-inducing function of miR-449a in multiple neuroblastoma cell lines. We have demonstrated that...miR-449a functions as an inducer of cell differentiation in neuroblastoma cell lines with distinct genetic backgrounds, including the MYCN

  14. DIRECT FUEL/CELL/TURBINE POWER PLANT

    SciTech Connect

    Hossein Ghezel-Ayagh

    2004-05-01

    This report includes the progress in development of Direct FuelCell/Turbine{reg_sign} (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide release to the environment, and potential cost competitiveness with existing combined cycle power plants. FCE successfully completed testing of the pre-alpha DFC/T hybrid power plant. This power plant was constructed by integration of a 250kW fuel cell stack and a microturbine. The tests of the cascaded fuel cell concept for achieving high fuel utilizations were completed. The tests demonstrated that the concept results in higher power plant efficiency. Also, the preliminary design of a 40 MW power plant including the key equipment layout and the site plan was completed.

  15. Transplantation and differentiation of donor cells in the cloned pigs

    SciTech Connect

    Shimada, Arata; Tomii, Ryo; Kano, Koichiro; Nagashima, Hiroshi . E-mail: hnagas@isc.meiji.ac.jp

    2006-06-02

    The application of nuclear transfer technology is an interesting approach to investigate stem and progenitor cell transplantation therapy. If stem cells are used as a nuclear donor, donor cells can engraft into cloned animals without histocompatible problems. However, it is still uncertain whether donor cells can engraft to cloned animal and differentiate in vivo. To address this problem, we transplanted donor cells to dermal tissues of cloned pigs developed by using preadipocytes as donor cells. Preadipocytes are adipocytic progenitor which can differentiate to mature adipocytes in vitro. We showed that the donor preadipocytes were successfully transplanted into the cloned pigs without immune rejection and they differentiated into mature adipocytes in vivo 3 weeks after transplantation. In contrast, allogenic control preadipocytes, which can differentiate in vitro, did not differentiate in vivo. These results indicate that donor progenitor cells can differentiate in cloned animal.

  16. Pyranocoumarins isolated from Peucedanum praeruptorum as differentiation inducers in human leukemic HL-60 cells.

    PubMed

    Zhang, Jin-Xia; Fong, Wang-Fun; Wu, Jimmy Yiu-Cheong; Yang, Mengsu; Cheung, Hon-Yeung

    2003-03-01

    Differentiation therapy for myeloid leukemia offers great potential as a supplement to the current treatment modalities. In the present report, we investigated if the pyranocoumarins, (+/-)-4'- O-acetyl-3'- O-angeloyl- cis-khellactone (or angular pyranocoumarin, APC) isolated from the medicinal plant Peucedanum praeruptorum Dunn, could induce human acute myeloid leukemic HL-60 cells to differentiate and elucidated the molecular mechanism(s) involved. The ability of HL-60 cells to reduce nitroblue tetrazolium (NBT) was significantly increased after APC treatment for 72 h. In these differentiating HL-60 cells, cell surface differentiation markers CD11b (for myeloid cells) and CD14 (for monocytic cells) were detected in 90.3 % and 70.1 % of the cells, respectively. The differentiation inducing effect of APC was time- and dose-dependent. Treatment with 20 microg/mL APC for 72 h inhibited cell growth by 90 % and cell cycle analysis revealed an increase in the proportion of G1 phase cells. In these growth-inhibited cells the expression of the cyclin-dependent kinase inhibitor p27 kip1, but not p21 WAF1, was up-regulated as shown by Western blotting. Differentiation inducing signal pathways were investigated and it was shown that phospho-MEK and phospho-ERK were elevated shortly after the addition of APC. Pre-incubation of the cells with MEK1 inhibitor PD98059 blocked this APC-induced differentiation. Our results suggest that APC are potent inducers of HL-60 cell differentiation along both the myelocytic and monocytic lineages and are potential agents for differentiation-treatment of leukemia.

  17. Mitochondrial respiration regulates adipogenic differentiation of human mesenchymal stem cells.

    PubMed

    Zhang, Yanmin; Marsboom, Glenn; Toth, Peter T; Rehman, Jalees

    2013-01-01

    Human mesenchymal stem cells (MSCs) are adult multipotent stem cells which can be isolated from bone marrow, adipose tissue as well as other tissues and have the capacity to differentiate into a variety of mesenchymal cell types such as adipocytes, osteoblasts and chondrocytes. Differentiation of stem cells into mature cell types is guided by growth factors and hormones, but recent studies suggest that metabolic shifts occur during differentiation and can modulate the differentiation process. We therefore investigated mitochondrial biogenesis, mitochondrial respiration and the mitochondrial membrane potential during adipogenic differentiation of human MSCs. In addition, we inhibited mitochondrial function to assess its effects on adipogenic differentiation. Our data show that mitochondrial biogenesis and oxygen consumption increase markedly during adipogenic differentiation, and that reducing mitochondrial respiration by hypoxia or by inhibition of the mitochondrial electron transport chain significantly suppresses adipogenic differentiation. Furthermore, we used a novel approach to suppress mitochondrial activity using a specific siRNA-based knockdown of the mitochondrial transcription factor A (TFAM), which also resulted in an inhibition of adipogenic differentiation. Taken together, our data demonstrates that increased mitochondrial activity is a prerequisite for MSC differentiation into adipocytes. These findings suggest that metabolic modulation of adult stem cells can maintain stem cell pluripotency or direct adult stem cell differentiation.

  18. Physalis angulata induces in vitro differentiation of murine bone marrow cells into macrophages

    PubMed Central

    2014-01-01

    Background The bone marrow is a hematopoietic tissue that, in the presence of cytokines and growth factors, generates all of the circulating blood cells. These cells are important for protecting the organism against pathogens and for establishing an effective immune response. Previous studies have shown immunomodulatory effects of different products isolated from plant extracts. This study aimed to evaluate the immunomodulatory properties of aqueous Physalis angulata (AEPa) extract on the differentiation of bone marrow cells. Results Increased cellular area, higher spreading ability and several cytoplasmatic projections were observed in the treated cells, using optical microscopy, suggesting cell differentiation. Furthermore, AEPa did not promote the proliferation of lymphocytes and polymorphonuclear leukocytes, however promotes increased the number of macrophages in the culture. The ultrastructural analysis by Transmission Electron Microscopy of treated cells showed spreading ability, high number of cytoplasmatic projections and increase of autophagic vacuoles. Moreover, a high level of LC3b expression by treated cells was detected by flow cytometry, suggesting an autophagic process. Cell surface expression of F4/80 and CD11b also indicated that AEPa may stimulate differentiation of bone marrow cells mainly into macrophages. In addition, AEPa did not differentiate cells into dendritic cells, as assessed by CD11c analysis. Furthermore, no cytotoxic effects were observed in the cells treated with AEPa. Conclusion Results demonstrate that AEPa promotes the differentiation of bone marrow cells, particularly into macrophages and may hold promise as an immunomodulating agent. PMID:25281406

  19. Multistep process of squamous differentiation in tracheobronchial epithelial cells in vitro: analogy with epidermal differentiation.

    PubMed Central

    Jetten, A M

    1989-01-01

    The lung, in particular the bronchial epithelium, is a major site for tumor formation in humans. Environmental factors, such as cigarette smoke, in conjunction with genetic factors are important determinants in this disease. Malignant cells exhibit alterations in their control of proliferation and differentiation. It is believed that the acquisition of defects in the regulation of these processes is important in the process of carcinogenesis. A clear insight into the basic mechanisms of the regulation of proliferation and differentiation is required to understand the molecular mechanisms involved in tumor development and in other pathological conditions. Studies using in vitro cell culture systems of tracheobronchial epithelial cells provide useful models in which to study the regulation of differentiation and proliferation. The clonogenic cells derived from the treacheobronchial epithelium are pluripotent: They have self-renewal capacity and can differentiate along either a normal, mucosecretory, or a squamous cell pathway. Squamous differentiation in tracheobronchial epithelial cells has many morphological, biochemical, and regulatory properties in common with epidermal differentiation. This pathway of differentiation is a multistep process consisting of at least three stages. In the initial stage, cells become committed to terminal cell division. This is followed by the expression of the squamous differentiated phenotype and finally cornification. Various factors, such as several growth factors, retinoids, calcium ions, and phorbol esters, regulate the program of differentiation at different stages. Studies have indicated that the controls of proliferation and differentiation are interrelated. Cell lines established from tracheobronchial epithelial cells expressing SV 40 large T-antigen, as well as carcinoma cell lines, exhibit altered responses to growth and differentiation regulatory factors. Alterations in the commitment to terminal cell division must be a

  20. Carbonate fuel cell power plant systems

    NASA Astrophysics Data System (ADS)

    Reinstrom, R. M.

    1981-12-01

    Carbonate fuel cells are an attractive means of developing highly efficient power plants capable of achieving low atmospheric emissions. Because carbonate fuel cells can be used with coal derived fuel gases and their operating temperatures allow the use of turbomachinery bottoming cycles, they are well suited for large installations like central utility stations. Presently, system development activity is directed toward evaluating the readiness of gasifier and fuel processor technology, defining candidate cycle configurations, and calculating projected plant efficiencies.

  1. Disposable Bioreactors for Plant Micropropagation and Mass Plant Cell Culture

    NASA Astrophysics Data System (ADS)

    Ducos, Jean-Paul; Terrier, Bénédicte; Courtois, Didier

    Different types of bioreactors are used at Nestlé R&D Centre - Tours for mass propagation of selected plant varieties by somatic embryogenesis and for large scale culture of plants cells to produce metabolites or recombinant proteins. Recent studies have been directed to cut down the production costs of these two processes by developing disposable cell culture systems. Vegetative propagation of elite plant varieties is achieved through somatic embryogenesis in liquid medium. A pilot scale process has recently been set up for the industrial propagation of Coffea canephora (Robusta coffee). The current production capacity is 3.0 million embryos per year. The pre-germination of the embryos was previously conducted by temporary immersion in liquid medium in 10-L glass bioreactors. An improved process has been developed using a 10-L disposable bioreactor consisting of a bag containing a rigid plastic box ('Box-in-Bag' bioreactor), insuring, amongst other advantages, a higher light transmittance to the biomass due to its horizontal design. For large scale cell culture, two novel flexible plastic-based disposable bioreactors have been developed from 10 to 100 L working volumes, validated with several plant species ('Wave and Undertow' and 'Slug Bubble' bioreactors). The advantages and the limits of these new types of bioreactor are discussed, based mainly on our own experience on coffee somatic embryogenesis and mass cell culture of soya and tobacco.

  2. Catalysts of plant cell wall loosening

    PubMed Central

    Cosgrove, Daniel J.

    2016-01-01

    The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyloglucan endotransglycosylase/hydrolase (XTH), and pectin methylesterases, and offer a critical assessment of their wall-loosening activity PMID:26918182

  3. Side Effects of Culture Media Antibiotics on Cell Differentiation.

    PubMed

    Llobet, Laura; Montoya, Julio; López-Gallardo, Ester; Ruiz-Pesini, Eduardo

    2015-11-01

    Besides the advance in scientific knowledge and the production of different compounds, cell culture can now be used to obtain cells for regenerative medicine. To avoid microbial contamination, antibiotics were usually incorporated into culture media. However, these compounds affect cell biochemistry and may modify the differentiation potential of cultured cells. To check this possibility, we grew human adipose tissue-derived stem cells and differentiated them to adipocyte with or without antibiotics commonly used in these culture protocols, such as a penicillin-streptomycin-amphotericin mix or gentamicin. We show that these antibiotics affect cell differentiation. Therefore, antibiotics should not be used in cell culture because aseptic techniques make these compounds unnecessary.

  4. 500-WATT FUEL-CELL POWER PLANT.

    DTIC Science & Technology

    hydrogen and air, fuel - cell power plant. Two independent units are to be developed - a hydrogen-generator assembly and a fuel - cell assembly. The...hydrogen-generator assembly will convert the hydrocarbon fuel to hydrogen by steam reforming, and the fuel - cell assembly will electrochemically oxidize the...The report presents the technical approach to be used to establish the feasibility of a compact 500-watt, liquid-hydrocarbon and air, fuel - cell power

  5. Interplay between cell growth and cell cycle in plants.

    PubMed

    Sablowski, Robert; Carnier Dornelas, Marcelo

    2014-06-01

    The growth of organs and whole plants depends on both cell growth and cell-cycle progression, but the interaction between both processes is poorly understood. In plants, the balance between growth and cell-cycle progression requires coordinated regulation of four different processes: macromolecular synthesis (cytoplasmic growth), turgor-driven cell-wall extension, mitotic cycle, and endocycle. Potential feedbacks between these processes include a cell-size checkpoint operating before DNA synthesis and a link between DNA contents and maximum cell size. In addition, key intercellular signals and growth regulatory genes appear to target at the same time cell-cycle and cell-growth functions. For example, auxin, gibberellin, and brassinosteroid all have parallel links to cell-cycle progression (through S-phase Cyclin D-CDK and the anaphase-promoting complex) and cell-wall functions (through cell-wall extensibility or microtubule dynamics). Another intercellular signal mediated by microtubule dynamics is the mechanical stress caused by growth of interconnected cells. Superimposed on developmental controls, sugar signalling through the TOR pathway has recently emerged as a central control point linking cytoplasmic growth, cell-cycle and cell-wall functions. Recent progress in quantitative imaging and computational modelling will facilitate analysis of the multiple interconnections between plant cell growth and cell cycle and ultimately will be required for the predictive manipulation of plant growth.

  6. Oral mucosal progenitor cell clones resist in vitro myogenic differentiation.

    PubMed

    Locke, Matthew; Davies, Lindsay C; Stephens, Phil

    2016-10-01

    Progenitor cells derived from the oral mucosa lamina propria (OMLP-PCs) demonstrate an ability to differentiate into tissue lineages removed from their anatomical origin. This clonally derived population of neural-crest cells have demonstrated potential to differentiate along mesenchymal and neuronal cell lineages.

  7. Plant expansins: diversity and interactions with plant cell walls

    PubMed Central

    Cosgrove, Daniel J.

    2015-01-01

    Expansins were discovered two decades ago as cell wall proteins that mediate acid-induced growth by catalyzing loosening of plant cell walls without lysis of wall polymers. In the interim our understanding of expansins has gotten more complex through bioinformatic analysis of expansin distribution and evolution, as well as through expression analysis, dissection of the upstream transcription factors regulating expression, and identification of additional classes of expansin by sequence and structural similarities. Molecular analyses of expansins from bacteria have identified residues essential for wall loosening activity and clarified the bifunctional nature of expansin binding to complex cell walls. Transgenic modulation of expansin expression modifies growth and stress physiology of plants, but not always in predictable and even understandable ways. PMID:26057089

  8. Plant expansins: diversity and interactions with plant cell walls.

    PubMed

    Cosgrove, Daniel J

    2015-06-01

    Expansins were discovered two decades ago as cell wall proteins that mediate acid-induced growth by catalyzing loosening of plant cell walls without lysis of wall polymers. In the interim our understanding of expansins has gotten more complex through bioinformatic analysis of expansin distribution and evolution, as well as through expression analysis, dissection of the upstream transcription factors regulating expression, and identification of additional classes of expansin by sequence and structural similarities. Molecular analyses of expansins from bacteria have identified residues essential for wall loosening activity and clarified the bifunctional nature of expansin binding to complex cell walls. Transgenic modulation of expansin expression modifies growth and stress physiology of plants, but not always in predictable or even understandable ways.

  9. DIRECT FUEL CELL/TURBINE POWER PLANT

    SciTech Connect

    Hossein Ghezel-Ayagh

    2004-11-01

    This report includes the progress in development of Direct FuelCell/Turbine{reg_sign} (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide release to the environment, and potential cost competitiveness with existing combined cycle power plants. The operation of sub-MW hybrid Direct FuelCell/Turbine power plant test facility with a Capstone C60 microturbine was initiated in March 2003. The inclusion of the C60 microturbine extended the range of operation of the hybrid power plant to higher current densities (higher power) than achieved in previous tests using a 30kW microturbine. The design of multi-MW DFC/T hybrid systems, approaching 75% efficiency on natural gas, was initiated. A new concept was developed based on clusters of One-MW fuel cell modules as the building blocks. System analyses were performed, including systems for near-term deployment and power plants with long-term ultra high efficiency objectives. Preliminary assessment of the fuel cell cluster concept, including power plant layout for a 14MW power plant, was performed.

  10. DIRECT FUEL CELL/TURBINE POWER PLANT

    SciTech Connect

    Hossein Ghezel-Ayagh

    2003-05-23

    In this reporting period, a milestone was achieved by commencement of testing and operation of the sub-scale hybrid direct fuel cell/turbine (DFC/T{reg_sign}) power plant. The operation was initiated subsequent to the completion of the construction of the balance-of-plant (BOP) and implementation of process and control tests of the BOP for the subscale DFC/T hybrid system. The construction efforts consisted of finishing the power plant insulation and completion of the plant instrumentation including the wiring and tubing required for process measurement and control. The preparation work also included the development of procedures for facility shake down, conditioning and load testing of the fuel cell, integration of the microturbine, and fuel cell/gas turbine load tests. At conclusion of the construction, the process and control (PAC) tests of BOP, including the microturbine, were initiated.

  11. Plant cell shape: modulators and measurements

    PubMed Central

    Ivakov, Alexander; Persson, Staffan

    2013-01-01

    Plant cell shape, seen as an integrative output, is of considerable interest in various fields, such as cell wall research, cytoskeleton dynamics and biomechanics. In this review we summarize the current state of knowledge on cell shape formation in plants focusing on shape of simple cylindrical cells, as well as in complex multipolar cells such as leaf pavement cells and trichomes. We summarize established concepts as well as recent additions to the understanding of how cells construct cell walls of a given shape and the underlying processes. These processes include cell wall synthesis, activity of the actin and microtubule cytoskeletons, in particular their regulation by microtubule associated proteins, actin-related proteins, GTP'ases and their effectors, as well as the recently-elucidated roles of plant hormone signaling and vesicular membrane trafficking. We discuss some of the challenges in cell shape research with a particular emphasis on quantitative imaging and statistical analysis of shape in 2D and 3D, as well as novel developments in this area. Finally, we review recent examples of the use of novel imaging techniques and how they have contributed to our understanding of cell shape formation. PMID:24312104

  12. Quantitative Aspects of Cyclosis in Plant Cells.

    ERIC Educational Resources Information Center

    Howells, K. F.; Fell, D. A.

    1979-01-01

    Describes an exercise which is currently used in a course in cell physiology at Oxford Polytechnic in England. This exercise can give students some idea of the molecular events involved in bringing about movement of chloroplasts (and other organelles) in plant cells. (HM)

  13. Direct FuelCell/Turbine Power Plant

    SciTech Connect

    Hossein Ghezel-Ayagh

    2004-11-19

    This report includes the progress in development of Direct Fuel Cell/Turbine. (DFC/T.) power plants for generation of clean power at very high efficiencies. The DFC/T power system is based on an indirectly heated gas turbine to supplement fuel cell generated power. The DFC/T power generation concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, 60% on coal gas, minimal emissions, simplicity in design, direct reforming internal to the fuel cell, reduced carbon dioxide release to the environment, and potential cost competitiveness with existing combined cycle power plants. FCE successfully completed testing of the pre-alpha sub-MW DFC/T power plant. This power plant was constructed by integration of a 250kW fuel cell stack and a microturbine. Following these proof-of-concept tests, a stand-alone test of the microturbine verified the turbine power output expectations at an elevated (representative of the packaged unit condition) turbine inlet temperature. Preliminary design of the packaged sub-MW alpha DFC/T unit has been completed and procurement activity has been initiated. The preliminary design of a 40 MW power plant including the key equipment layout and the site plan was completed. A preliminary cost estimate for the 40 MW DFC/T plant has also been prepared. The tests of the cascaded fuel cell concept for achieving high fuel utilizations were completed. The tests demonstrated that the concept results in higher power plant efficiency. Alternate stack flow geometries for increased power output/fuel utilization capabilities are also being evaluated.

  14. Extracellular Matrix and Integrins in Embryonic Stem Cell Differentiation

    PubMed Central

    Wang, Han; Luo, Xie; Leighton, Jake

    2015-01-01

    Embryonic stem cells (ESCs) are pluripotent cells with great therapeutic potentials. The in vitro differentiation of ESC was designed by recapitulating embryogenesis. Significant progress has been made to improve the in vitro differentiation protocols by toning soluble maintenance factors. However, more robust methods for lineage-specific differentiation and maturation are still under development. Considering the complexity of in vivo embryogenesis environment, extracellular matrix (ECM) cues should be considered besides growth factor cues. ECM proteins bind to cells and act as ligands of integrin receptors on cell surfaces. Here, we summarize the role of the ECM and integrins in the formation of three germ layer progenies. Various ECM–integrin interactions were found, facilitating differentiation toward definitive endoderm, hepatocyte-like cells, pancreatic beta cells, early mesodermal progenitors, cardiomyocytes, neuroectoderm lineages, and epidermal cells, such as keratinocytes and melanocytes. In the future, ECM combinations for the optimal ESC differentiation environment will require substantial study. PMID:26462244

  15. A Change In Nuclear Pore Complex Composition Regulates Cell Differentiation

    PubMed Central

    D’Angelo, Maximiliano A.; Gomez-Cavazos, J. Sebastian; Mei, Arianna; Lackner, Daniel H.; Hetzer, Martin W.

    2011-01-01

    SUMMARY Nuclear pore complexes (NPCs) are built from ~30 different proteins called nucleoporins. Previous studies have shown that several Nups exhibit cell-type-specific expression and that mutations in NPC components result in tissue-specific diseases. Here we show that a specific change in NPC composition is required for both myogenic and neuronal differentiation. The transmembrane nucleoporin Nup210 is absent in proliferating myoblasts and embryonic stem (ES) cells but becomes expressed and incorporated into NPCs during cell differentiation. Preventing Nup210 production by RNAi blocks myogenesis and the differentiation of ES cells into neuroprogenitors. We found that the addition of Nup210 to NPCs does not affect nuclear transport but is required for the induction of genes that are essential for cell differentiation. Our results identify a single change in NPC composition as an essential step in cell differentiation and establish a role for Nup210 in gene expression regulation and cell fate determination. PMID:22264802

  16. SETD7 Regulates the Differentiation of Human Embryonic Stem Cells

    PubMed Central

    Castaño, Julio; Morera, Cristina; Sesé, Borja; Boue, Stephanie; Bonet-Costa, Carles; Martí, Merce; Roque, Alicia; Jordan, Albert; Barrero, Maria J.

    2016-01-01

    The successful use of specialized cells in regenerative medicine requires an optimization in the differentiation protocols that are currently used. Understanding the molecular events that take place during the differentiation of human pluripotent cells is essential for the improvement of these protocols and the generation of high quality differentiated cells. In an effort to understand the molecular mechanisms that govern differentiation we identify the methyltransferase SETD7 as highly induced during the differentiation of human embryonic stem cells and differentially expressed between induced pluripotent cells and somatic cells. Knock-down of SETD7 causes differentiation defects in human embryonic stem cell including delay in both the silencing of pluripotency-related genes and the induction of differentiation genes. We show that SETD7 methylates linker histone H1 in vitro causing conformational changes in H1. These effects correlate with a decrease in the recruitment of H1 to the pluripotency genes OCT4 and NANOG during differentiation in the SETD7 knock down that might affect the proper silencing of these genes during differentiation. PMID:26890252

  17. Distinct T helper cell dependence of memory B-cell proliferation versus plasma cell differentiation.

    PubMed

    Zabel, Franziska; Fettelschoss, Antonia; Vogel, Monique; Johansen, Pål; Kündig, Thomas M; Bachmann, Martin F

    2017-03-01

    Several memory B-cell subclasses with distinct functions have been described, of which the most effective is the class-switched (CS) memory B-cell population. We have previously shown, using virus-like particles (VLPs), that the proliferative potential of these CS memory B cells is limited and they fail to re-enter germinal centres (GCs). However, VLP-specific memory B cells quickly differentiated into secondary plasma cells (PCs) with the virtue of elevated antibody production compared with primary PCs. Whereas the induction of VLP(+) memory B cells was strongly dependent on T helper cells, we were wondering whether re-stimulation of VLP(+) memory B cells and their differentiation into secondary PCs would also require T helper cells. Global absence of T helper cells led to strongly impaired memory B cell proliferation and PC differentiation. In contrast, lack of interleukin-21 receptor-dependent follicular T helper cells or CD40 ligand signalling strongly affected proliferation of memory B cells, but differentiation into mature secondary PCs exhibiting increased antibody production was essentially normal. This contrasts with primary B-cell responses, where a strong dependence on CD40 ligand but limited importance of interleukin-21 receptor was seen. Hence, T helper cell dependence differs between primary and secondary B-cell responses as well as between memory B-cell proliferation and PC differentiation.

  18. Phosphorylation of the Polarity Protein BASL Differentiates Asymmetric Cell Fate through MAPKs and SPCH.

    PubMed

    Zhang, Ying; Guo, Xiaoyu; Dong, Juan

    2016-11-07

    Cell polarization is commonly used for the regulation of stem cell asymmetric division in both animals and plants. Stomatal development in Arabidopsis, a process that produces breathing pores in the epidermis, requires asymmetric cell division to differentiate highly specialized guard cells while maintaining a stem cell population [1, 2]. The BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) protein exhibits a polarized localization pattern in the cell and is required for differential cell fates resulting from asymmetric cell division [3]. The polarization of BASL is made possible by a positive feedback loop with a canonical mitogen-activated protein kinase (MAPK) pathway that recruits the MAPKK kinase YODA (YDA) and MAPK 6 (MPK6) to the cortical polarity site [4]. Here, we study BASL intracellular dynamics and show that the membrane-associated BASL is slowly replenished at the cortical polarity site and that the mobility is tightly linked to its phosphorylation status. Because BASL polarity is only exhibited by one daughter cell after an asymmetric cell division, we study how BASL differentially functions in the two daughter cells. The YDA MAPK cascade transduces upstream ligand-receptor signaling [5-13] to the transcription factor SPEECHLESS (SPCH), which controls stomatal initiation and is directly suppressed by MPK3/6-mediated phosphorylation [14, 15]. We show that BASL polarization leads to elevated nuclear MPK6 signaling and lowered SPCH abundance in one of the two daughter cells. Therefore, two daughter cells are differentiated by BASL polarity-mediated differential suppression of SPCH, which may provide developmental plasticity in plant stem cell asymmetric cell division (ACD).

  19. Differentiation of pluripotent stem cells for regenerative medicine.

    PubMed

    Li, Ke; Kong, Yan; Zhang, Mingliang; Xie, Fei; Liu, Peng; Xu, Shaohua

    2016-02-26

    A long-standing goal in regenerative medicine is to obtain scalable functional cells on demand to replenish cells lost in various conditions, including relevant diseases, injuries, and aging. As an unlimited cell source, pluripotent stem cells (PSCs) are invaluable for regenerative medicine, because they have the potential to give rise to any cell type in an organism. For therapeutic purposes, it is important to develop specific approach to directing PSC differentiation towards desired cell types efficiently. Through directed differentiation, PSCs could give rise to scalable, clinically relevant cells for in vivo transplantation, as well as for studying diseases in vitro and discovering drugs to treat them. Over the past few years, significant progress has been made in directing differentiation of PSCs into a variety of cell types. In this review, we discuss recent progress in directed differentiation of PSCs, clinical translation of PSC-based cell replacement therapies, and remaining challenges.

  20. Derivation and spontaneous differentiation of human embryonic stem cells*

    PubMed Central

    Amit, Michal; Itskovitz-Eldor, Joseph

    2002-01-01

    Abstract Embryonic stem (ES) cells are unique cells derived from the inner cell mass of the mammalian blastocyst. These cells are immortal and pluripotent, retain their developmental potential after prolonged culture, and can be continuously cultured in an undifferentiated state. Many in vitro differentiation systems have been developed for mouse ES cells, including reproducible methods for mouse ES cell differentiation into haematopoietic and neural precursors, cardiomyocytes, insulin-secreting cells, endothelial cells and various other cell types. The derivation of new human ES cell lines provides the opportunity to develop unique models for developmental research and for cell therapies. In this review we consider the derivation and spontaneous differentiation of human ES cells. PMID:12033726

  1. Non-genetic heterogeneity, criticality and cell differentiation

    NASA Astrophysics Data System (ADS)

    Pal, Mainak; Ghosh, Sayantari; Bose, Indrani

    2015-02-01

    The different cell types in a living organism acquire their identity through the process of cell differentiation in which multipotent progenitor cells differentiate into distinct cell types. Experimental evidence and analysis of large-scale microarray data establish the key role played by a two-gene motif in cell differentiation in a number of cell systems. The two genes express transcription factors which repress each other's expression and autoactivate their own production. A number of theoretical models have recently been proposed based on the two-gene motif to provide a physical understanding of how cell differentiation occurs. In this paper, we study a simple model of cell differentiation which assumes no cooperativity in the regulation of gene expression by the transcription factors. The latter repress each other's activity directly through DNA binding and indirectly through the formation of heterodimers. We specifically investigate how deterministic processes combined with stochasticity contribute in bringing about cell differentiation. The deterministic dynamics of our model give rise to a supercritical pitchfork bifurcation from an undifferentiated stable steady state to two differentiated stable steady states. The stochastic dynamics of our model are studied using the approaches based on the Langevin equations and the linear noise approximation. The simulation results provide a new physical understanding of recent experimental observations. We further propose experimental measurements of quantities like the variance and the lag-1 autocorrelation function in protein fluctuations as the early signatures of an approaching bifurcation point in the cell differentiation process.

  2. Chemically induced bidirectional differentiation of embryonal carcinoma cells in vitro.

    PubMed Central

    Speers, W. C.; Birdwell, C. R.; Dixon, F. J.

    1979-01-01

    N,N-dimethylacetamide, hexamethylene bisacetamide, and Polybrene induced rapid and extensive differentiation in vitro in an otherwise slowly differentiating subline of embryonal carcinoma cells. The type of differentiated cell induced was dependent on the spatial organization of the stem cells during drug treatment. In monalayer culture "epithelial" cells were produced exclusively. However, treatment of aggregated suspension cultures yielded predominantly "fibroblast-like" cells. The undifferentiated embryonal carcinoma cells and the two differentiated cell types were morphologically distinct when examined by light microscopy, scanning electron microscopy, and transmission electron microscopy; and they had differences in cell surface antigens. Both differential cell types produced large amounts of fibronectin, whereas the embryonal carcinoma cells produced only minimal amounts. This system provides a convenient way to induce relatively synchronous differentiation of embryonal carcinoma cells into specific differentiated cell types. Images Figure 5 Figure 6 Figure 1 Figure 2 Figure 3 Figure 4 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 PMID:507191

  3. Ricin trafficking in plant and mammalian cells.

    PubMed

    Lord, J Michael; Spooner, Robert A

    2011-07-01

    Ricin is a heterodimeric plant protein that is potently toxic to mammalian and many other eukaryotic cells. It is synthesized and stored in the endosperm cells of maturing Ricinus communis seeds (castor beans). The ricin family has two major members, both, lectins, collectively known as Ricinus communis agglutinin ll (ricin) and Ricinus communis agglutinin l (RCA). These proteins are stored in vacuoles within the endosperm cells of mature Ricinus seeds and they are rapidly broken down by hydrolysis during the early stages of post-germinative growth. Both ricin and RCA traffic within the plant cell from their site of synthesis to the storage vacuoles, and when they intoxicate mammalian cells they traffic from outside the cell to their site of action. In this review we will consider both of these trafficking routes.

  4. Symbiotic Cell Differentiation and Cooperative Growth in Multicellular Aggregates

    PubMed Central

    Yamagishi, Jumpei F; Saito, Nen; Kaneko, Kunihiko

    2016-01-01

    As cells grow and divide under a given environment, they become crowded and resources are limited, as seen in bacterial biofilms and multicellular aggregates. These cells often show strong interactions through exchanging chemicals, as evident in quorum sensing, to achieve mutualism and division of labor. Here, to achieve stable division of labor, three characteristics are required. First, isogenous cells differentiate into several types. Second, this aggregate of distinct cell types shows better growth than that of isolated cells without interaction and differentiation, by achieving division of labor. Third, this cell aggregate is robust with respect to the number distribution of differentiated cell types. Indeed, theoretical studies have thus far considered how such cooperation is achieved when the ability of cell differentiation is presumed. Here, we address how cells acquire the ability of cell differentiation and division of labor simultaneously, which is also connected with the robustness of a cell society. For this purpose, we developed a dynamical-systems model of cells consisting of chemical components with intracellular catalytic reaction dynamics. The reactions convert external nutrients into internal components for cellular growth, and the divided cells interact through chemical diffusion. We found that cells sharing an identical catalytic network spontaneously differentiate via induction from cell-cell interactions, and then achieve division of labor, enabling a higher growth rate than that in the unicellular case. This symbiotic differentiation emerged for a class of reaction networks under the condition of nutrient limitation and strong cell-cell interactions. Then, robustness in the cell type distribution was achieved, while instability of collective growth could emerge even among the cooperative cells when the internal reserves of products were dominant. The present mechanism is simple and general as a natural consequence of interacting cells with

  5. Plant single-cell and single-cell-type metabolomics.

    PubMed

    Misra, Biswapriya B; Assmann, Sarah M; Chen, Sixue

    2014-10-01

    In conjunction with genomics, transcriptomics, and proteomics, plant metabolomics is providing large data sets that are paving the way towards a comprehensive and holistic understanding of plant growth, development, defense, and productivity. However, dilution effects from organ- and tissue-based sampling of metabolomes have limited our understanding of the intricate regulation of metabolic pathways and networks at the cellular level. Recent advances in metabolomics methodologies, along with the post-genomic expansion of bioinformatics knowledge and functional genomics tools, have allowed the gathering of enriched information on individual cells and single cell types. Here we review progress, current status, opportunities, and challenges presented by single cell-based metabolomics research in plants.

  6. The plastic liver: differentiated cells, stem cells, every cell?

    PubMed Central

    Hindley, Christopher J.; Mastrogiovanni, Gianmarco; Huch, Meritxell

    2014-01-01

    The liver is capable of full regeneration following several types and rounds of injury, ranging from hepatectomy to toxin-mediated damage. The source of this regenerative capacity has long been a hotly debated topic. The damage response that occurs when hepatocyte proliferation is impaired is thought to be mediated by oval/dedifferentiated progenitor cells, which replenish the hepatocyte and ductal compartments of the liver. Recently, reports have questioned whether these oval/progenitor cells truly serve as the facultative stem cell of the liver following toxin-mediated damage. In this issue of the JCI, Kordes and colleagues use lineage tracing to follow transplanted rat hepatic stellate cells, a resident liver mesenchymal cell population, in hosts that have suffered liver damage. Transplanted stellate cells repopulated the damaged rat liver by contributing to the oval cell response. These data establish yet another cell type of mesenchymal origin as the progenitor for the oval/ductular response in the rat. The lack of uniformity between different damage models, the extent of the injury to the liver parenchyma, and potential species-specific differences might be at the core of the discrepancy between different studies. Taken together, these data imply a considerable degree of plasticity in the liver, whereby several cell types can contribute to regeneration. PMID:25401467

  7. Monoclonal antibodies against plant cell wall polysaccharides

    SciTech Connect

    Hahn, M.G.; Bucheli, E.; Darvill, A.; Albersheim, P. )

    1989-04-01

    Monoclonal antibodies (McAbs) are useful tools to probe the structure of plant cell wall polysaccharides and to localize these polysaccharides in plant cells and tissues. Murine McAbs were generated against the pectic polysaccharide, rhamnogalacturonan I (RG-I), isolated from suspension-cultured sycamore cells. The McAbs that were obtained were grouped into three classes based upon their reactivities with a variety of plant polysaccharides and membrane glycoproteins. Eleven McAbs (Class I) recognize epitope(s) that appear to be immunodominant and are found in RG-I from sycamore and maize, citrus pectin, polygalacturonic acid, and membrane glycoproteins from suspension-cultured cells of sycamore, maize, tobacco, parsley, and soybean. A second group of five McAbs (Class II) recognize epitope(s) present in sycamore RG-I, but do not bind to any of the other polysaccharides or glycoproteins recognized by Class I. Lastly, one McAb (Class III) reacts with sycamore RG-I, sycamore and tamarind xyloglucan, and sycamore and rice glucuronoarabinoxylan, but does not bind to maize RG-I, polygalacturonic acid or the plant membrane glycoproteins recognized by Class I. McAbs in Classes II and III are likely to be useful in studies of the structure, biosynthesis and localization of plant cell wall polysaccharides.

  8. A Lin28 homologue reprograms differentiated cells to stem cells in the moss Physcomitrella patens

    PubMed Central

    Li, Chen; Sako, Yusuke; Imai, Akihiro; Nishiyama, Tomoaki; Thompson, Kari; Kubo, Minoru; Hiwatashi, Yuji; Kabeya, Yukiko; Karlson, Dale; Wu, Shu-Hsing; Ishikawa, Masaki; Murata, Takashi; Benfey, Philip N.; Sato, Yoshikatsu; Tamada, Yosuke; Hasebe, Mitsuyasu

    2017-01-01

    Both land plants and metazoa have the capacity to reprogram differentiated cells to stem cells. Here we show that the moss Physcomitrella patens Cold-Shock Domain Protein 1 (PpCSP1) regulates reprogramming of differentiated leaf cells to chloronema apical stem cells and shares conserved domains with the induced pluripotent stem cell factor Lin28 in mammals. PpCSP1 accumulates in the reprogramming cells and is maintained throughout the reprogramming process and in the resultant stem cells. Expression of PpCSP1 is negatively regulated by its 3′-untranslated region (3′-UTR). Removal of the 3′-UTR stabilizes PpCSP1 transcripts, results in accumulation of PpCSP1 protein and enhances reprogramming. A quadruple deletion mutant of PpCSP1 and three closely related PpCSP genes exhibits attenuated reprogramming indicating that the PpCSP genes function redundantly in cellular reprogramming. Taken together, these data demonstrate a positive role of PpCSP1 in reprogramming, which is similar to the function of mammalian Lin28. PMID:28128346

  9. RIMA-dependent nuclear accumulation of IYO triggers auxin-irreversible cell differentiation in Arabidopsis.

    PubMed

    Muñoz, Alfonso; Mangano, Silvina; González-García, Mary Paz; Contreras, Ramón; Sauer, Michael B; De Rybel, Bert; Weijers, Dolf; Sánchez-Serrano, José J; Sanmartín, Maite; Rojo, Enrique

    2017-02-21

    The transcriptional regulator MINIYO (IYO) is essential and rate-limiting for initiating cell differentiation in Arabidopsis thaliana. Moreover, IYO moves from the cytosol into the nucleus in cells at the meristem periphery, possibly triggering their differentiation. However, the genetic mechanisms controlling IYO nuclear accumulation were unknown and the evidence that increased nuclear IYO levels trigger differentiation remained correlative. Searching for IYO interactors, we have identified RPAP2 IYO Mate (RIMA), a homologue of yeast and human proteins linked to nuclear import of selective cargo. Knockdown of RIMA causes delayed onset of cell differentiation, phenocopying the effects of IYO knock down at the transcriptomic and developmental levels. Moreover, differentiation is completely blocked when IYO and RIMA activities are simultaneously reduced and is synergistically accelerated when IYO and RIMA are concurrently overexpressed, confirming their functional interaction. Indeed, RIMA knockdown reduces the nuclear levels of IYO and prevents its pro-differentiation activity, supporting the conclusion that RIMA-dependent nuclear IYO accumulation triggers cell differentiation in Arabidopsis. Importantly, by analysing the effect of the IYO/RIMA pathway on xylem pole pericycle cells, we provide compelling evidence reinforcing the view that the capacity for de novo organogenesis and regeneration from mature plant tissues can reside in stem cell reservoirs.

  10. Graphene Oxide promotes embryonic stem cell differentiation to haematopoietic lineage

    PubMed Central

    Garcia-Alegria, Eva; Iluit, Maria; Stefanska, Monika; Silva, Claudio; Heeg, Sebastian; Kimber, Susan J.; Kouskoff, Valerie; Lacaud, Georges; Vijayaraghavan, Aravind; Batta, Kiran

    2016-01-01

    Pluripotent stem cells represent a promising source of differentiated tissue-specific stem and multipotent progenitor cells for regenerative medicine and drug testing. The realisation of this potential relies on the establishment of robust and reproducible protocols of differentiation. Several reports have highlighted the importance of biomaterials in assisting directed differentiation. Graphene oxide (GO) is a novel material that has attracted increasing interest in the field of biomedicine. In this study, we demonstrate that GO coated substrates significantly enhance the differentiation of mouse embryonic stem (ES) cells to both primitive and definitive haematopoietic cells. GO does not affect cell proliferation or survival of differentiated cells but rather enhances the transition of haemangioblasts to haemogenic endothelial cells, a key step during haematopoietic specification. Importantly, GO also improves, in addition to murine, human ES cell differentiation to blood cells. Taken together, our study reveals a positive role for GO in haematopoietic differentiation and suggests that further functionalization of GO could represent a valid strategy for the generation of large numbers of functional blood cells. Producing these cells would accelerate haematopoietic drug toxicity testing and treatment of patients with blood disorders or malignancies. PMID:27197878

  11. DIRECT FUEL CELL/TURBINE POWER PLANT

    SciTech Connect

    Hossein Ghezel-Ayagh

    2003-05-27

    The subMW hybrid DFC/T power plant facility was upgraded with a Capstone C60 microturbine and a state-of-the-art full size fuel cell stack. The integration of the larger microturbine extended the capability of the hybrid power plant to operate at high power ratings with a single gas turbine without the need for supplementary air. The objectives of this phase of subMW hybrid power plant tests are to support the development of process and control and to provide the insight for the design of the packaged subMW hybrid demonstration units. The development of the ultra high efficiency multi-MW power plants was focused on the design of 40 MW power plants with efficiencies approaching 75% (LHV of natural gas). The design efforts included thermodynamic cycle analysis of key gas turbine parameters such as compression ratio.

  12. UV-Induced cell death in plants.

    PubMed

    Nawkar, Ganesh M; Maibam, Punyakishore; Park, Jung Hoon; Sahi, Vaidurya Pratap; Lee, Sang Yeol; Kang, Chang Ho

    2013-01-14

    Plants are photosynthetic organisms that depend on sunlight for energy. Plants respond to light through different photoreceptors and show photomorphogenic development. Apart from Photosynthetically Active Radiation (PAR; 400-700 nm), plants are exposed to UV light, which is comprised of UV-C (below 280 nm), UV-B (280-320 nm) and UV-A (320-390 nm). The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation. Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants. It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation. The important targets of UV radiation in plant cells are DNA, lipids and proteins and also vital processes such as photosynthesis. Recent studies showed that, in response to UV radiation, mitochondria and chloroplasts produce a reactive oxygen species (ROS). Arabidopsis metacaspase-8 (AtMC8) is induced in response to oxidative stress caused by ROS, which acts downstream of the radical induced cell death (AtRCD1) gene making plants vulnerable to cell death. The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death. Recently, molecular studies have revealed genes involved in response to UV exposure, with respect to programmed cell death (PCD).

  13. Expression of bacterial genes in plant cells.

    PubMed Central

    Fraley, R T; Rogers, S G; Horsch, R B; Sanders, P R; Flick, J S; Adams, S P; Bittner, M L; Brand, L A; Fink, C L; Fry, J S; Galluppi, G R; Goldberg, S B; Hoffmann, N L; Woo, S C

    1983-01-01

    Chimeric bacterial genes conferring resistance to aminoglycoside antibiotics have been inserted into the Agrobacterium tumefaciens tumor-inducing (Ti) plasmid and introduced into plant cells by in vitro transformation techniques. The chimeric genes contain the nopaline synthase 5' and 3' regulatory regions joined to the genes for neomycin phosphotransferase type I or type II. The chimeric genes were cloned into an intermediate vector, pMON120, and inserted into pTiB6S3 by recombination and then introduced into petunia and tobacco cells by cocultivating A. tumefaciens cells with protoplast-derived cells. Southern hybridization was used to confirm the presence of the chimeric genes in the transformed plant tissues. Expression of the chimeric genes was determined by the ability of the transformed cells to proliferate on medium containing normally inhibitory levels of kanamycin (50 micrograms/ml) or other aminoglycoside antibiotics. Plant cells transformed by wild-type pTiB6S3 or derivatives carrying the bacterial neomycin phosphotransferase genes with their own promoters failed to grow under these conditions. The significance of these results for plant genetic engineering is discussed. Images PMID:6308651

  14. Tocopherol production in plant cell cultures.

    PubMed

    Caretto, Sofia; Nisi, Rossella; Paradiso, Annalisa; De Gara, Laura

    2010-05-01

    Tocopherols, collectively known as vitamin E, are lipophilic antioxidants, essential dietary components for mammals and exclusively synthesized by photosynthetic organisms. Of the four forms (alpha, beta, gamma and delta), alpha-tocopherol is the major vitamin E form present in green plant tissues, and has the highest vitamin E activity. Synthetic alpha-tocopherol, being a racemic mixture of eight different stereoisomers, always results less effective than the natural form (R,R,R) alpha-tocopherol. This raises interest in obtaining this molecule from natural sources, such as plant cell cultures. Plant cell and tissue cultures are able to produce and accumulate valuable metabolites that can be used as food additives, nutraceuticals and pharmaceuticals. Sunflower cell cultures, growing under heterotrophic conditions, were exploited to establish a suitable in vitro production system of natural alpha-tocopherol. Optimization of culture conditions, precursor feeding and elicitor application were used to improve the tocopherol yields of these cultures. Furthermore, these cell cultures were useful to investigate the relationship between alpha-tocopherol biosynthesis and photomixotrophic culture conditions, revealing the possibility to enhance tocopherol production by favouring sunflower cell photosynthetic properties. The modulation of alpha-tocopherol levels in plant cell cultures can provide useful hints for a regulatory impact on tocopherol metabolism.

  15. Identifying microRNAs that Regulate Neuroblastoma Cell Differentiation

    DTIC Science & Technology

    2014-09-01

    AD_________________ Award Number: W81XWH-13-1-0241 TITLE: Identifying that Regulate Neuroblastoma ...Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT We identified 14 microRNA candidates that induce neuroblastoma cell differentiation based on a high...content screening of neurite outgrowth — the morphological differentiation marker of neuroblastoma cells. We further validated that the identified

  16. Electrical Property Characterization of Neural Stem Cells in Differentiation

    PubMed Central

    Sun, He; Chen, Deyong; Li, Zhaohui; Fan, Beiyuan; George, Julian; Xue, Chengcheng; Cui, Zhanfeng; Wang, Junbo

    2016-01-01

    Electrical property characterization of stem cells could be utilized as a potential label-free biophysical approach to evaluate the differentiation process. However, there has been a lack of technology or tools that can quantify the intrinsic cellular electrical markers (e.g., specific membrane capacitance (Cspecific membrane) and cytoplasm conductivity (σcytoplasm)) for a large amount of stem cells or differentiated cells. In this paper, a microfluidic platform enabling the high-throughput quantification of Cspecific membrane and σcytoplasm from hundreds of single neural stem cells undergoing differentiation was developed to explore the feasibility to characterize the neural stem cell differentiation process without biochemical staining. Experimental quantification using biochemical markers (e.g., Nestin, Tubulin and GFAP) of neural stem cells confirmed the initiation of the differentiation process featured with gradual loss in cellular stemness and increased cell markers for neurons and glial cells. The recorded electrical properties of neural stem cells undergoing differentiation showed distinctive and unique patterns: 1) in the suspension culture before inducing differentiation, a large distribution and difference in σcytoplasm among individual neural stem cells was noticed, which indicated heterogeneity that may result from the nature of suspension culture of neurospheres; and 2) during the differentiation in adhering monolayer culture, significant changes and a large difference in Cspecific membrane were located indicating different expressions of membrane proteins during the differentiation process, and a small distribution difference in σcytoplasm was less significant that indicated the relatively consistent properties of cytoplasm during the culture. In summary, significant differences in Cspecific membrane and σcytoplasm were observed during the neural stem cell differentiation process, which may potentially be used as label-free biophysical markers

  17. Osmosis in Poisoned Plant Cells.

    ERIC Educational Resources Information Center

    Tatina, Robert

    1998-01-01

    Describes two simple laboratory exercises that allow students to test hypotheses concerning the requirement of cell energy for osmosis. The first exercise involves osmotically-caused changes in the length of potato tubers and requires detailed quantitative observations. The second exercise involves osmotically-caused changes in turgor of Elodea…

  18. Regulation of cell division in higher plants. Final technical report

    SciTech Connect

    Jacobs, Thomas W.

    2000-02-29

    Research in the latter part of the grant period was divided into two parts: (1) expansion of the macromolecular tool kit for studying plant cell division; (2) experiments in which the roles played by plant cell cycle regulators were to be cast in the light of the emerging yeast and animal cell paradigm for molecular control of the mitotic cycle. The first objectives were accomplished to a very satisfactory degree. With regard to the second part of the project, we were driven to change our objectives for two reasons. First, the families of cell cycle control genes that we cloned encoded such closely related members that the prospects for success at raising distinguishing antisera against each were sufficiently dubious as to be impractical. Epitope tagging is not feasible in Pisum sativum, our experimental system, as this species is not realistically transformable. Therefore, differentiating the roles of diverse cyclins and cyclin-dependent kinases was problematic. Secondly, our procedure for generating mitotically synchronized pea root meristems for biochemical studies was far too labor intensive for the proposed experiments. We therefore shifted our objectives to identifying connections between the conserved proteins of the cell cycle engine and factors that interface it with plant physiology and development. In this, we have obtained some very exciting results.

  19. Calcium signaling in plant cells in microgravity

    NASA Astrophysics Data System (ADS)

    Kordyum, E.

    Changes in the intracellular Ca 2 + concentration in altered gravity (microgravity and clinostating) evidence that Ca2 + signaling can play a fundamental role in biological effects of microgravity. Calcium as a second messenger is known to play a crucial role in stimulus - response coupling for many plant cellular signaling pathways. Its messenger functions are realized by transient changes in the cytosolic ion concentration induced by a variety of internal and external stimuli such as light, hormones, temperature, anoxia, salinity, and gravity. Although the first data on the changes in the calcium balance in plant cells under the influence of altered gravity have appeared in eighties, a review highlighting the performed research and the possible significance of such Ca 2 + changes in the structural and metabolic rearrangements of plant cells in altered gravity is still lacking. In this paper, an attempt was made to summarize the available experimental results and to consider some hypotheses in this field of research. It is proposed to distinguish between cell gravisensing and cell graviperception; the former is related to cell structure and metabolism stability in the gravitational field and their changes in microgravity (cells not specialized to gravity perception), the latter is related to active use of a gravitational stimulus by cells presumably specialized to gravity perception for realization of normal space orientation, growth, and vital activity (gravitropism, gravitaxis) in plants. The main experimental data concerning both redistribution of free Ca 2 + ions in plant cell organelles and the cell wall, and an increase in the intracellular Ca 2+ concentration under the influence of altered gravity are presented. Based on the gravitational decompensation hypothesis, the consequence of events occurring in gravis ensing cells not specialized to gravity perception under altered gravity are considered in the following order: changes in the cytoplasmic membrane

  20. Phenylacetate synergizes with retinoic acid in inducing the differentiation of human neuroblastoma cells.

    PubMed

    Sidell, N; Wada, R; Han, G; Chang, B; Shack, S; Moore, T; Samid, D

    1995-02-08

    Phenylacetate, a natural metabolite of phenylalanine which was originally described as a plant growth hormone, has recently gained attention as a possible differentiation inducer for a variety of human tumor cell types. This interest prompted us to assess the ability of sodium phenylacetate (NaPA) to promote the differentiation of human neuroblastoma cells, both alone and in combination with retinoic acid (RA), a known inducer of neuroblastoma differentiation and maturation. Using the LA-N-5 cell line, we have determined that NaPA can stimulate the differentiation of neuroblastoma cells, as evidenced by dose-dependent inhibition of cell proliferation, neurite outgrowth, increased acetylcholinesterase activity and reduction of N-myc expression. Furthermore, NaPA and RA synergized in inducing differentiation, in that combination treatment resulted in cessation of cell growth along with morphologic and biochemical changes indicative of the loss of malignant properties. We have determined that NaPA can markedly enhance mRNA levels of the nuclear RA receptor-beta (RAR beta) in LA-N-5 cells prior to morphologic or other phenotypic changes induced by this compound. This effect appeared to be distinct from the ability of NaPA to alter tumor cell lipid metabolism via inhibition of protein isoprenylation. Thus among its varied effects on LA-N-5 cells, NaPA appears to interact with the RA pathway at the nuclear level by up-regulating RAR beta expression.

  1. Culture and differentiation of mouse tracheal epithelial cells.

    PubMed

    You, Yingjian; Brody, Steven L

    2013-01-01

    Airway epithelial cell biology has been greatly advanced by studies of genetically defined and modified mice; however it is often difficult to isolate, manipulate, and assay epithelial cell-specific responses in vivo. In vitro proliferation and differentiation of mouse airway epithelial cells are made possible by a high-fidelity system for primary culture of mouse tracheal epithelial cells described in this chapter. Using this method, epithelial cells purified from mouse tracheas proliferate in growth factor-enriched medium. Subsequent culture in defined medium and the use of the air-liquid interface condition result in the development of well-differentiated epithelia composed of ciliated and non-ciliated cells with characteristics of native airways. Methods are also provided for manipulation of differentiation and analysis of differentiation and gene expression. These approaches allow the assessment of global responses and those of specific cell subpopulations within the airway epithelium.

  2. The topographical regulation of embryonic stem cell differentiation.

    PubMed Central

    Murray, Patricia; Edgar, David

    2004-01-01

    The potential use of pluripotent stem cells for tissue repair or replacement is now well recognized. While the ability of embryonic stem (ES) cells to differentiate into all cells of the body is undisputed, their use is currently restricted by our limited knowledge of the mechanisms controlling their differentiation. This review discusses recent work by ourselves and others investigating the intercellular signalling events that occur within aggregates of mouse ES cells. The work illustrates that the processes of ES cell differentiation, epithelialization and programmed cell death are dependent upon their location within the aggregates and coordinated by the extracellular matrix. Establishment of the mechanisms involved in these events is not only of use for the manipulation of ES cells themselves, but it also throws light on the ways in which differentiation is coordinated during embryogenesis. PMID:15306413

  3. Nitric oxide-cyclic GMP signaling in stem cell differentiation

    PubMed Central

    Mujoo, Kalpana; Krumenacker, Joshua S.; Murad, Ferid

    2011-01-01

    The nitric oxide-cyclic GMP (NO-cGMP) pathway mediates important physiological functions associated with various integrative body systems including the cardiovascular and nervous systems. Furthermore, NO regulates cell growth, survival, apoptosis, proliferation and differentiation at the cellular level. To understand the significance of the NO-cGMP pathway in development and differentiation, studies have been conducted both in developing embryos and stem cells. Manipulation of the NO-cGMP pathway by employing activators and inhibitors as pharmacological probes and/or genetic manipulation of NO signaling components has implicated the involvement of this pathway in regulation of stem cell differentiation. This review will focus on some of the work pertaining to the role of NO-cGMP in differentiation of stem cells into cells of various lineages particularly into myocardial cells and stem cell based therapy. PMID:22019632

  4. Diclofenac and triamcinolone acetonide impair tenocytic differentiation and promote adipocytic differentiation of mesenchymal stem cells

    PubMed Central

    2013-01-01

    Background Tendinopathies are often empirically treated with oral/topical nonsteroidal anti-inflammatory medications and corticosteroid injections despite their unclear effects on tendon regeneration. Recent studies indicate that tendon progenitors exhibit stem cell-like properties, i.e., differentiation to osteoblasts, adipocytes, and chondrocytes, in addition to tenocytes. Our present study aims at understanding the effects of triamcinolone acetonide and diclofenac on tenocytic differentiation of mesenchymal stem cells. Methods The murine fibroblast C3H10T1/2 cell line was induced to tenocytic differentiation by growth differentiation factor-7. Cell proliferation and differentiation with the exposure of different concentrations of triamcinolone acetonide and diclofenac were measured by WST-1 assay and real-time polymerase chain reaction analysis, respectively. Results Cell proliferation was decreased in a concentration-dependent manner when exposed to triamcinolone acetonide and diclofenac. In addition to tenocytic differentiation, adipocyte formation was observed, both at gene expression and microscopic level, when the cells were exposed to triamcinolone acetonide or high concentrations of diclofenac. Conclusions Our results indicate that triamcinolone acetonide and diclofenac might alter mesenchymal stem cell differentiation in a nonfavorable way regarding tendon regeneration; therefore, these medications should be used with more caution clinically. PMID:24004657

  5. Sonic Hedgehog Activation Is Implicated in Diosgenin-Induced Megakaryocytic Differentiation of Human Erythroleukemia Cells

    PubMed Central

    Ghezali, Lamia; Liagre, Bertrand; Limami, Youness; Beneytout, Jean-Louis; Leger, David Yannick

    2014-01-01

    Differentiation therapy is a means to treat cancer and is induced by different agents with low toxicity and more specificity than traditional ones. Diosgenin, a plant steroid, is able to induce megakaryocytic differentiation or apoptosis in human HEL erythroleukemia cells in a dose-dependent manner. However, the exact mechanism by which diosgenin induces megakaryocytic differentiation has not been elucidated. In this study, we studied the involvement of Sonic Hedgehog in megakaryocytic differentiation induced by diosgenin in HEL cells. First, we showed that different elements of the Hedgehog pathway are expressed in our model by qRT-PCR. Then, we focused our interest on key elements in the Sonic Hedgehog pathway: Smoothened receptor, GLI transcription factor and the ligand Sonic Hedgehog. We showed that Smoothened and Sonic Hedgehog were overexpressed in disogenin-treated cells and that GLI transcription factors were activated. Then, we showed that SMO inhibition using siSMO or the GLI antagonist GANT-61, blocked megakaryocytic differentiation induced by diosgenin in HEL cells. Furthermore, we demonstrated that Sonic Hedgehog pathway inhibition led to inhibition of ERK1/2 activation, a major physiological pathway involved in megakaryocytic differentiation. In conclusion, our study reports, for the first time, a crucial role for the Sonic Hedgehog pathway in diosgenin-induced megakaryocytic differentiation in HEL cells. PMID:24740159

  6. Sonic Hedgehog activation is implicated in diosgenin-induced megakaryocytic differentiation of human erythroleukemia cells.

    PubMed

    Ghezali, Lamia; Liagre, Bertrand; Limami, Youness; Beneytout, Jean-Louis; Leger, David Yannick

    2014-01-01

    Differentiation therapy is a means to treat cancer and is induced by different agents with low toxicity and more specificity than traditional ones. Diosgenin, a plant steroid, is able to induce megakaryocytic differentiation or apoptosis in human HEL erythroleukemia cells in a dose-dependent manner. However, the exact mechanism by which diosgenin induces megakaryocytic differentiation has not been elucidated. In this study, we studied the involvement of Sonic Hedgehog in megakaryocytic differentiation induced by diosgenin in HEL cells. First, we showed that different elements of the Hedgehog pathway are expressed in our model by qRT-PCR. Then, we focused our interest on key elements in the Sonic Hedgehog pathway: Smoothened receptor, GLI transcription factor and the ligand Sonic Hedgehog. We showed that Smoothened and Sonic Hedgehog were overexpressed in disogenin-treated cells and that GLI transcription factors were activated. Then, we showed that SMO inhibition using siSMO or the GLI antagonist GANT-61, blocked megakaryocytic differentiation induced by diosgenin in HEL cells. Furthermore, we demonstrated that Sonic Hedgehog pathway inhibition led to inhibition of ERK1/2 activation, a major physiological pathway involved in megakaryocytic differentiation. In conclusion, our study reports, for the first time, a crucial role for the Sonic Hedgehog pathway in diosgenin-induced megakaryocytic differentiation in HEL cells.

  7. Metal-accelerated oxidation in plant cell death

    SciTech Connect

    Czuba, M. )

    1993-05-01

    Cadmium and mercury toxicity is further enhanced by external oxidizing conditions O[sub 3] or inherent plant processes. Lepidium sativum L, Lycopersicon esculentum Mill., or Phaseolus vulgaris L, were grown inpeat-lite to maturity under continuous cadmium exposure followed by one oxidant (O[sub 3]-6 hr. 30 pphm) exposure, with or without foliar calcium pretreatments. In comparison, Daucus carota, L and other species grown in a 71-V suspension, with or without 2,4-D were exposed continuously to low levels of methylmercury during exponential growth and analyzed in aggregates of distinct populations. Proteins were extracted and analyzed. Mechanisms of toxicity and eventual cell death are Ca-mediated and involve chloroplast, stomatal-water relations and changes in oxidant-anti-oxidant components in cells. Whether the metal-accelerated oxidative damage proceeds to cell death, depends on the species and its differential biotransformation system and cell association component.

  8. Recent advances in plant cell wall proteomics.

    PubMed

    Jamet, Elisabeth; Albenne, Cécile; Boudart, Georges; Irshad, Muhammad; Canut, Hervé; Pont-Lezica, Rafael

    2008-02-01

    The plant extracellular matrix contains typical polysaccharides such as cellulose, hemicelluloses, and pectins that interact to form dense interwoven networks. Plant cell walls play crucial roles during development and constitute the first barrier of defense against invading pathogens. Cell wall proteomics has greatly contributed to the description of the protein content of a compartment specific to plants. Around 400 cell wall proteins (CWPs) of Arabidopsis, representing about one fourth of its estimated cell wall proteome, have been described. The main points to note are that: (i) the diversity of enzymes acting on polysaccharides suggests a great plasticity of cell walls; (ii) CWPs such as proteases, polysaccharide hydrolytic enzymes, and lipases may contribute to the generation of signals; (iii) proteins of unknown functions were identified, suggesting new roles for cell walls. Recently, the characterization of PTMs such as N- and O-glycosylations improved our knowledge of CWP structure. The presence of many glycoside hydrolases and proteases suggests a complex regulation of CWPs involving various types of post-translational events. The first 3-D structures to be resolved gave clues about the interactions between CWPs, or between CWPs and polysaccharides. Future work should include: extracting and identifying CWPs still recalcitrant to proteomics, describing the cell wall interactome, improving quantification, and unraveling the roles of each of the CWPs.

  9. NOV/CCN3 impairs muscle cell commitment and differentiation

    SciTech Connect

    Calhabeu, Frederico; Lafont, Jerome; Le Dreau, Gwenvael; Laurent, Maryvonne; Kazazian, Chantal; Schaeffer, Laurent; Dubois, Catherine . E-mail: dubois@st-antoine.inserm.frs

    2006-06-10

    NOV (nephroblastoma overexpressed) is a member of a family of proteins which encodes secreted matrix-associated proteins. NOV is expressed during development in dermomyotome and limb buds, but its functions are still poorly defined. In order to understand the role of NOV in myogenic differentiation, C2C12 cells overexpressing NOV (C2-NOV) were generated. These cells failed to engage into myogenic differentiation, whereas they retained the ability to differentiate into osteoblasts. In differentiating conditions, C2-NOV cells remained proliferative, failed to express differentiation markers and lost their ability to form myotubes. Inhibition of differentiation by NOV was also observed with human primary muscle cells. Further examination of C2-NOV cells revealed a strong downregulation of the myogenic determination genes MyoD and Myf5 and of IGF-II expression. MyoD forced expression in C2-NOV was sufficient to restore differentiation and IGF-II induction whereas 10{sup -6} M insulin treatment had no effects. NOV therefore acts upstream of MyoD and does not affect IGF-II induction and signaling. HES1, a target of Notch, previously proposed to mediate NOV action, was not implicated in the inhibition of differentiation. We propose that NOV is a specific cell fate regulator in the myogenic lineage, acting negatively on key myogenic genes thus controlling the transition from progenitor cells to myoblasts.

  10. Plant cell cultures: bioreactors for industrial production.

    PubMed

    Ruffoni, Barbara; Pistelli, Laura; Bertoli, Alessandra; Pistelli, Luisa

    2010-01-01

    The recent biotechnology boom has triggered increased interest in plant cell cultures, since a number of firms and academic institutions investigated intensively to rise the production of very promising bioactive compounds. In alternative to wild collection or plant cultivation, the production of useful and valuable secondary metabolites in large bioreactors is an attractive proposal; it should contribute significantly to future attempts to preserve global biodiversity and alleviate associated ecological problems. The advantages of such processes include the controlled production according to demand and a reduced man work requirement. Plant cells have been grown in different shape bioreactors, however, there are a variety of problems to be solved before this technology can be adopted on a wide scale for the production of useful plant secondary metabolites. There are different factors affecting the culture growth and secondary metabolite production in bioreactors: the gaseous atmosphere, oxygen supply and CO2 exchange, pH, minerals, carbohydrates, growth regulators, the liquid medium rheology and cell density. Moreover agitation systems and sterilization conditions may negatively influence the whole process. Many types ofbioreactors have been successfully used for cultivating transformed root cultures, depending on both different aeration system and nutrient supply. Several examples of medicinal and aromatic plant cultures were here summarized for the scale up cultivation in bioreactors.

  11. Differentiation of embryonic stem cells into corneal epithelium.

    PubMed

    Wang, Zhichong; Ge, Jian; Huang, Bing; Gao, Qianying; Liu, Bingqian; Wang, Linghua; Yu, Ling; Fan, Zhigang; Lu, Xiaoming; Liu, Jingbo

    2005-10-01

    Our project was to determine whether embryonic stem (ES) cells could be induced to differentiate into corneal epithelia by superficial corneoscleral limbal stroma. To achieve this goal, ES-GFP cell line D3 was pre-induced by retinoic acid (RA). The pre-induced cells were seeded on deepithelialized superficial corneoscleral slices (SCSS) to form a monolayer, and divided into three groups. Group 1 was cultured and passaged in vitro for direct detection. Group 2 was exposed to air-liquid interfaces for 10 days and implanted into the subcutaneous layer of nude mice for 2 weeks for further induction in vivo. Group 3 was cultured in vitro without any inducing factors for control. There were no teratomas found in nude mice which were implanted with differentiated ES cells after two weeks. The differentiated cells showed an appearance of epithelia both in vitro and in vivo. Expression of CK3, P63 and PCNA was detected by immunohistochemical staining in the differentiated cells in group 1 and 2. Microvillis and zonula occludens were observed on the surface of the differentiated cells under an electron microscope. In the control group, ES cells differentiated freely without any inducing factors. Most cells were shed and formed a neuronal dendrite-like structure, and a minority of cells appeared polymorphic. These results demonstrate that ES cells can differentiate into corneal epithelia on the surface of SCSS under the controlled condition. Differentiated ES cells could be used as epithelial seeding cells for the reconstruction of ocular surface and corneal tissue engineering in the future.

  12. Direct FuelCell/Turbine Power Plant

    SciTech Connect

    Hossein Ghezel-Ayagh

    2008-09-30

    This report summarizes the progress made in development of Direct FuelCell/Turbine (DFC/T{reg_sign}) power plants for generation of clean power at very high efficiencies. The DFC/T system employs an indirectly heated Turbine Generator to supplement fuel cell generated power. The concept extends the high efficiency of the fuel cell by utilizing the fuel cell's byproduct heat in a Brayton cycle. Features of the DFC/T system include: electrical efficiencies of up to 75% on natural gas, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design, direct reforming internal to the fuel cell, and potential cost competitiveness with existing combined cycle power plants. Proof-of-concept tests using a sub-MW-class DFC/T power plant at FuelCell Energy's (FCE) Danbury facility were conducted to validate the feasibility of the concept and to measure its potential for electric power production. A 400 kW-class power plant test facility was designed and retrofitted to conduct the tests. The initial series of tests involved integration of a full-size (250 kW) Direct FuelCell stack with a 30 kW Capstone microturbine. The operational aspects of the hybrid system in relation to the integration of the microturbine with the fuel cell, process flow and thermal balances, and control strategies for power cycling of the system, were investigated. A subsequent series of tests included operation of the sub-MW Direct FuelCell/Turbine power plant with a Capstone C60 microturbine. The C60 microturbine extended the range of operation of the hybrid power plant to higher current densities (higher power) than achieved in initial tests using the 30kW microturbine. The proof-of-concept test results confirmed the stability and controllability of operating a fullsize (250 kW) fuel cell stack in combination with a microturbine. Thermal management of the system was confirmed and power plant operation, using the microturbine as the only source of fresh air supply to the

  13. Fourier transform infrared spectroscopic analysis of cell differentiation

    NASA Astrophysics Data System (ADS)

    Ishii, Katsunori; Kimura, Akinori; Kushibiki, Toshihiro; Awazu, Kunio

    2007-02-01

    Stem cells and its differentiations have got a lot of attentions in regenerative medicine. The process of differentiations, the formation of tissues, has become better understood by the study using a lot of cell types progressively. These studies of cells and tissue dynamics at molecular levels are carried out through various approaches like histochemical methods, application of molecular biology and immunology. However, in case of using regenerative sources (cells, tissues and biomaterials etc.) clinically, they are measured and quality-controlled by non-invasive methods from the view point of safety. Recently, the use of Fourier Transform Infrared spectroscopy (FT-IR) has been used to monitor biochemical changes in cells, and has gained considerable importance. The objective of this study is to establish the infrared spectroscopy of cell differentiation as a quality control of cell sources for regenerative medicine. In the present study, as a basic study, we examined the adipose differentiation kinetics of preadipocyte (3T3-L1) and the osteoblast differentiation kinetics of bone marrow mesenchymal stem cells (Kusa-A1) to analyze the infrared absorption spectra. As a result, we achieved to analyze the adipose differentiation kinetics using the infrared absorption peak at 1739 cm-1 derived from ester bonds of triglyceride and osteoblast differentiation kinetics using the infrared absorption peak at 1030 cm-1 derived from phosphate groups of calcium phosphate.

  14. Insulin acts as a myogenic differentiation signal for neural stem cells with multilineage differentiation potential.

    PubMed

    Bani-Yaghoub, Mahmud; Kendall, Stephen E; Moore, Daniel P; Bellum, Stephen; Cowling, Rebecca A; Nikopoulos, George N; Kubu, Chris J; Vary, Calvin; Verdi, Joseph M

    2004-09-01

    Reports of non-neural differentiation of neural stem cells (NSCs) have been challenged by alternative explanations for expanded differentiation potentials. In an attempt to demonstrate the plasticity of NSC, neurospheres were generated from single retrovirally labeled embryonic cortical precursors. In a defined serum-free insulin-containing media, 40% of the neurospheres contained both myogenic and neurogenic differentiated progeny. The number of NSCs displaying multilineage differentiation potential declines through gestation but does exist in the adult animal. In this system, insulin appears to function as a survival and dose-dependent myogenic differentiation signal for multilineage NSCs (MLNSC). MLNSC-derived cardiomyocytes contract synchronously, respond to sympathetic and parasympathetic stimulation, and regenerate injured heart tissues. These studies provide support for the hypothesis that MLNSCs exist throughout the lifetime of the animal, and potentially provide a population of stem cells for cell-based regenerative medicine strategies inside and outside of the nervous system.

  15. Epigenetic stability increases extensively during Drosophila follicle stem cell differentiation.

    PubMed

    Skora, Andrew D; Spradling, Allan C

    2010-04-20

    Stem and embryonic cells facilitate programming toward multiple daughter cell fates, whereas differentiated cells resist reprogramming and oncogenic transformation. How alterations in the chromatin-based machinery of epigenetic inheritance contribute to these differences remains poorly known. We observed random, heritable changes in GAL4/UAS transgene programming during Drosophila ovarian follicle stem cell differentiation and used them to measure the stage-specific epigenetic stability of gene programming. The frequency of GAL4/UAS reprogramming declines more than 100-fold over the nine divisions comprising this stem cell lineage. Stabilization acts in cis, suggesting that it is chromatin-based, and correlates with increased S phase length. Our results suggest that stem/early progenitor cells cannot accurately transmit nongenetic information to their progeny; full epigenetic competence is acquired only gradually during early differentiation. Modulating epigenetic inheritance may be a critical process controlling transitions between the pleuripotent and differentiated states.

  16. Regulation of Human Helper T Cell Subset Differentiation by Cytokines

    PubMed Central

    Schmitt, Nathalie; Ueno, Hideki

    2015-01-01

    Since the discovery of Th1 and Th2 cells in the late 80’s, the family of effector CD4+ helper T (Th) cell subsets has expanded. The differentiation of naïve CD4+ T cells is largely determined when they interact with dendritic cells in lymphoid organs, and cytokines play a major role in the regulation of Th differentiation in the early stages. Recent studies show that the developmental mechanism of certain Th subsets is not fully shared between mice and humans. Here we will review recent discoveries on the roles of cytokines in the regulation of Th differentiation in humans, and discuss the differences between mice and humans in the developmental mechanisms of several Th subsets, including Th17 cells and T follicular helper (Tfh) cells. We propose that the differentiation of human Th subsets is largely regulated by the three cytokines, IL-12, IL-23, and TGF-β. PMID:25879814

  17. DIRECT FUEL CELL/TURBINE POWER PLANT

    SciTech Connect

    Hossein Ghezel-Ayagh

    2003-05-22

    Project activities were focused on the design and construction the sub-scale hybrid Direct Fuel Cell/turbine (DFC/T{reg_sign}) power plant and modification of a Capstone Simple Cycle Model 330 microturbine. The power plant design work included preparation of system flow sheet and performing computer simulations based on conservation of mass and energy. The results of the simulation analyses were utilized to prepare data sheets and specifications for balance-of-plant equipment. Process flow diagram (PFD) and piping and instrumentation diagrams (P&ID) were also completed. The steady state simulation results were used to develop design information for modifying the control functions, and for sizing the heat exchangers required for recuperating the waste heat from the power plant. Line and valve sizes for the interconnecting pipes between the microturbine and the heat recuperators were also identified.

  18. Epigenetic Control of Cell Division and Cell Differentiation in the Root Apex

    PubMed Central

    Takatsuka, Hirotomo; Umeda, Masaaki

    2015-01-01

    Epigenetics is defined as heritable changes in gene expression and genome integrity that are accompanied by no alteration in DNA sequence. Throughout plant life cycle, many processes, including genome imprinting, stress responses, and cellular differentiation, are known to be determined by epigenetic regulation. The root apex is also considered to be under the control of epigenetic regulation for optimal growth under variable environments. Recent reports reveal that epigenetic control is especially important in the stem cell niche and the meristematic zone where both cell production and cell specification occur. DNA methylation, histone methylation, and histone acetylation are well-known epigenetic modifications, and each epigenetic modification has distinct roles in roots. Here, we review the updated findings that demonstrate the significance of epigenetic regulation in root apex of Arabidopsis. PMID:26734056

  19. Distinct Signaling Pathways and Transcriptome Response Signatures Differentiate Ammonium- and Nitrate-supplied Plants

    PubMed Central

    Patterson, Kurt; Cakmak, Turgay; Cooper, Andrew; Lager, Ida; Rasmusson, Allan G.; Escobar, Matthew A.

    2010-01-01

    Nitrogen is the only macronutrient that is commonly available to plants in both oxidized and reduced forms, mainly nitrate and ammonium. The physiological and molecular effects of nitrate supply have been well studied, but comparatively little is known about ammonium nutrition and its differential effects on cell function and gene expression. We have used a physiologically realistic hydroponic growth system to compare the transcriptomes and redox status of the roots of ammonium- and nitrate-supplied Arabidopsis thaliana plants. While ~60% of nitrogen-regulated genes displayed common responses to both ammonium and nitrate, significant “nitrate-specific” and “ammonium-specific” gene sets were identified. Pathways involved in cytokinin response and reductant generation/distribution were specifically altered by nitrate, while a complex biotic stress response and changes in nodulin gene expression were characteristic of ammonium-supplied plants. Nitrate supply was associated with a rapid decrease in H2O2 production, potentially due to an increased export of reductant from the mitochondrial matrix. The underlying basis of the nitrate- and ammonium-specific patterns of gene expression appears to be different signals elaborated from each nitrogen source, including alterations in extracellular pH that are associated with ammonium uptake, downstream metabolites in the ammonium assimilation pathway, and the presence or absence of the nitrate ion. PMID:20444219

  20. Integrated bioprocessing for plant cell cultures.

    PubMed

    Choi, J W; Cho, G H; Byun, S Y; Kim, D I

    2001-01-01

    Plant cell suspension culture has become the focus of much attention as a tool for the production of secondary metabolites including paclitaxel, a well-known anticancer agent. Recently, it has also been regarded as one of the host systems for the production of recombinant proteins. In order to produce phytochemicals using plant cell cultures, efficient processes must be developed with adequate bioreactor design. Most of the plant secondary metabolites are toxic to cells at the high concentrations required during culture. Therefore, if the product could be removed in situ during culture, productivity might be enhanced due to the alleviation of this toxicity. In situ removal or extractive bioconversion of such products can be performed by in situ extraction with various kinds of organic solvents. In situ adsorption using polymeric resins is another possibility. Using the fact that secondary metabolites are generally hydrophobic, various integrated bioprocessing techniques can be designed not only to lower toxicity, but also to enhance productivity. In this article, in situ extraction, in situ adsorption, utilization of cyclodextrins, and the application of aqueous two-phase systems in plant cell cultures are reviewed.

  1. B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation.

    PubMed

    Harmon, Charles M; Smith, Lauren B

    2016-03-01

    B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.

  2. Directed stem cell differentiation: the role of physical forces.

    PubMed

    Clause, Kelly C; Liu, Li J; Tobita, Kimimasa

    2010-04-01

    A number of factors contribute to the control of stem cell fate. In particular, the evidence for how physical forces control the stem cell differentiation program is now accruing. In this review, the authors discuss the types of physical forces: mechanical forces, cell shape, extracellular matrix geometry/properties, and cell-cell contacts and morphogenic factors, which evidence suggests play a role in influencing stem cell fate.

  3. How to let go: pectin and plant cell adhesion.

    PubMed

    Daher, Firas Bou; Braybrook, Siobhan A

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell's life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells' ability to hang on, and how it lets go.

  4. Epigenomics of T cell activation, differentiation and memory

    PubMed Central

    Cuddapah, Suresh; Barski, Artem; Zhao, Keji

    2010-01-01

    Activation of T cells is an essential step in the immunological response to infection. While activation of naïve T cells results in proliferation and slow differentiation into cytokine-producing effector cells, antigen engagement with memory cells leads to cytokine production immediately. Even though the cell surface signaling events are similar in both the cases, the outcome is different, suggesting that distinct regulatory mechanisms may exist downstream of the activation signals. Recent advances in the understanding of global epigenetic patterns in T cells have resulted in the appreciation of the role of epigenetic mechanisms in processes such as activation and differentiation. In this review we discuss recent data suggesting that naïve T cell activation, differentiation and lineage commitment results in epigenetic changes and a fine balance between different histone modifications is required. On the other hand, memory T cells are poised and do not require epigenetic changes for short-term activation. PMID:20226645

  5. The Effect of Spaceflight on Cartilage Cell Cycle and Differentiation

    NASA Technical Reports Server (NTRS)

    Doty, Stephen B.; Stiner, Dalina; Telford, William G.

    2000-01-01

    In vivo studies have shown that spaceflight results in loss of bone and muscle. In an effort to understand the mechanisms of these changes, cell cultures of cartilage, bone and muscle have been subjected to spaceflight to study the microgravity effects on differentiated cells. However it now seems possible that the cell differentiation process itself may be the event(s) most affected by spaceflight. For example, osteoblast-like cells have been shown to have reduced cellular activity in microgravity due to an underdifferentiated state (Carmeliet, et al, 1997). And reduced human lymphocyte growth in spaceflight was related to increased apoptosis (Lewis, et al, 1998). Which brings us to the question of whether reduced cellular activity in space is due to an effect on the differentiated cell, an effect on the cell cycle and cell proliferation, or an effect on cell death. This question has not been specifically addressed on previous flights and was the question behind die present study.

  6. Timing mechanism dependent on cell division is invoked by Polycomb eviction in plant stem cells.

    PubMed

    Sun, Bo; Looi, Liang-Sheng; Guo, Siyi; He, Zemiao; Gan, Eng-Seng; Huang, Jiangbo; Xu, Yifeng; Wee, Wan-Yi; Ito, Toshiro

    2014-01-31

    Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay. AG binding sites colocalize with a Polycomb response element in the KNU upstream region. AG binding to the KNU promoter causes the eviction of the Polycomb group proteins from the locus, leading to cell division-dependent induction. These analyses demonstrate that floral stem cells measure developmental timing by a division-dependent epigenetic timer triggered by Polycomb eviction.

  7. Genomic characterization of plant cell wall degrading enzymes and in silico analysis of xylanses and polygalacturonases of Fusarium virguliforme

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant cell wall degrading enzymes (PCWDEs) are important effectors for plant pathogens to invade plants. In this study, the composition of PCWDEs in Fusarium virguliforme that were grown for 5-days and 20 days in liquid medium was determined by RNA-Seq. Differential expression analysis showed more P...

  8. Id2 reinforces TH1 cell differentiation and inhibits E2A to repress TFH cell differentiation

    PubMed Central

    Shaw, Laura A.; Bélanger, Simon; Omilusik, Kyla D.; Cho, Sunglim; Scott-Browne, James P.; Nance, J. Philip; Goulding, John; Lasorella, Anna; Lu, Li-Fan; Crotty, Shane; Goldrath, Ananda W.

    2016-01-01

    Differentiation of T helper (TH) effector subsets is critical for host protection. E protein transcription factors and Id proteins are important arbiters of T cell development, but their role in differentiation of TH1 and TFH cells is not well understood. TH1 cells showed robust Id2 expression compared to TFH cells, and RNAi depletion of Id2 increased TFH cell frequencies. Further, TH1 cell differentiation was blocked by Id2 deficiency, leading to E protein-dependent accumulation of effector cells with mixed characteristics during viral infection and severely impaired generation of TH1 cells following Toxoplasma gondii infection. The TFH-defining transcriptional repressor Bcl6 bound the Id2 locus, providing a mechanism for the bimodal Id2 expression and reciprocal development of TH1 and TFH cell fates. PMID:27213691

  9. Fibronectin and stem cell differentiation – lessons from chondrogenesis

    PubMed Central

    Singh, Purva; Schwarzbauer, Jean E.

    2012-01-01

    Summary The extracellular matrix (ECM) is an intricate network of proteins that surrounds cells and has a central role in establishing an environment that is conducive to tissue-specific cell functions. In the case of stem cells, this environment is the stem cell niche, where ECM signals participate in cell fate decisions. In this Commentary, we describe how changes in ECM composition and mechanical properties can affect cell shape and stem cell differentiation. Using chondrogenic differentiation as a model, we examine the changes in the ECM that occur before and during mesenchymal stem cell differentiation. In particular, we focus on the main ECM protein fibronectin, its temporal expression pattern during chondrogenic differentiation, its potential effects on functions of differentiating chondrocytes, and how its interactions with other ECM components might affect cartilage development. Finally, we discuss data that support the possibility that the fibronectin matrix has an instructive role in directing cells through the condensation, proliferation and/or differentiation stages of cartilage formation. PMID:22976308

  10. Quantitative phosphoproteome analysis of embryonic stem cell differentiation toward blood

    PubMed Central

    Piazzi, Manuela; Williamson, Andrew; Lee, Chia-Fang; Pearson, Stella; Lacaud, Georges; Kouskoff, Valerie; McCubrey, James A.; Cocco, Lucio; Whetton, Anthony D.

    2015-01-01

    Murine embryonic stem (ES) cells can differentiate in vitro into three germ layers (endodermic, mesodermic, ectodermic). Studies on the differentiation of these cells to specific early differentiation stages has been aided by an ES cell line carrying the Green Fluorescent Protein (GFP) targeted to the Brachyury (Bry) locus which marks mesoderm commitment. Furthermore, expression of the Vascular Endothelial Growth Factor receptor 2 (Flk1) along with Bry defines hemangioblast commitment. Isobaric-tag for relative and absolute quantification (iTRAQTM) and phosphopeptide enrichment coupled to liquid chromatography separation and mass spectrometry allow the study of phosphorylation changes occurring at different stages of ES cell development using Bry and Flk1 expression respectively. We identified and relatively quantified 37 phosphoentities which are modulated during mesoderm-induced ES cells differentiation, comparing epiblast-like, early mesoderm and hemangioblast-enriched cells. Among the proteins differentially phosphorylated toward mesoderm differentiation were: the epigenetic regulator Dnmt3b, the protein kinase GSK3b, the chromatin remodeling factor Smarcc1, the transcription factor Utf1; as well as protein specifically related to stem cell differentiation, as Eomes, Hmga2, Ints1 and Rif1. As most key factors regulating early hematopoietic development have also been implicated in various types of leukemia, understanding the post-translational modifications driving their regulation during normal development could result in a better comprehension of their roles during abnormal hematopoiesis in leukemia. PMID:25890499

  11. Plant development: cell movement relative to each other is both common and very important.

    PubMed

    Lev-Yadun, Simcha

    2015-01-01

    The common view that "plant cells cannot move relative to each other" is incorrect. Relative movement of plant cells relative to each other is expressed during fiber elongation, growth of arms of branched sclereids, intrusive growth of the tips of fusiform initials in the cambium, the increase in diameter of vessel members, growth in length of vessel-member elements in the secondary xylem of the few monocotyledons that express secondary growth, growth of laticifers, formation of tylosis, dilatation in the bark via parenchyma cell expansion, and growth of pollen tubes in the style. In all these cases, part of the plant cell remains in its original position, while other parts of the cell grow to the new locations, moving significantly relative to other cells. Not considering these movements will cause a delay in studying and understanding many aspects of differentiation of plant cells and tissues.

  12. Plant cells on earth and in space.

    PubMed

    Braun, M; Sievers, A

    2000-09-01

    Two quite different types of plant cells are analysed with regard to transduction of the gravity stimulus: (i) Unicellular rhizoids and protonemata of characean green algae; these are tube-like, tip-growing cells which respond to the direction of gravity. (ii) Columella cells located in the center of the root cap of higher plants; these cells (statocytes) perceive gravity. The two cell types contain heavy particles or organelles (statoliths) which sediment in the field of gravity, thereby inducing the graviresponse. Both cell types were studied under microgravity conditions (10(-4) g) in sounding rockets or spacelabs. From video microscopy of living Chara cells and different experiments with both cell types it was concluded that the position of statoliths depends on the balance of two forces, i.e. the gravitational force and the counteracting force mediated by actin microfilaments. The actomyosin system may be the missing link between the gravity-dependent movement of statoliths and the gravity receptor(s); it may also function as an amplifier.

  13. Cisplatin impaired adipogenic differentiation of adipose mesenchymal stem cells.

    PubMed

    Chang, Yu-Hsun; Liu, Hwan-Wun; Chu, Tang-Yuan; Wen, Yao-Tseng; Ding, Dah-Ching

    2017-02-03

    Adipose mesenchymal stem cells (ASCs) were isolated from the adipose tissue and can be induced in vitro to differentiate into osteoblasts, chondroblasts, myocytes, neurons and other cell types. Cisplatin is a commonly used chemotherapy drug for cancer patients. However, the effects of cisplatin on ASC remain elusive. This study found that high-concentration cisplatin affects the viability of ASCs. First, IC50 concentration of cisplatin was evaluated. Proliferation of ASCs assessed by XTT method decreased immediately after cisplatin treatment with various concentrations. ASCs maintained mesenchymal stem cells surface markers evaluating by flow cytometry after cisplatin treatment. Upon differentiation by adding specific chemicals, a significant decrease in adipogenic differentiation (by Oil red staining) and osteogenic differentiation (by Alizarin red staining), and significant chondrogenic differentiation (by Alcian blue staining) were found after cisplatin treatment. Simultaneously, qRT-PCR was also used for evaluating the specific gene expressions after various differentiations. Finally, ASCs from one donor who had received cisplatin showed significantly decreased adipogenic differentiation but increased osteogenic differentiation compared with ASCs derived from one healthy donor. In conclusion, cisplatin affects the viability, proliferation, and differentiation of ASCs both in vitro and in vivo via certain signaling pathway such as p53 and Fas/FasL. The differentiation abilities of ASCs should be evaluated before their transplantation for repairing cisplatin-induced tissue damage.

  14. Role of Hox genes in stem cell differentiation.

    PubMed

    Seifert, Anne; Werheid, David F; Knapp, Silvana M; Tobiasch, Edda

    2015-04-26

    Hox genes are an evolutionary highly conserved gene family. They determine the anterior-posterior body axis in bilateral organisms and influence the developmental fate of cells. Embryonic stem cells are usually devoid of any Hox gene expression, but these transcription factors are activated in varying spatial and temporal patterns defining the development of various body regions. In the adult body, Hox genes are among others responsible for driving the differentiation of tissue stem cells towards their respective lineages in order to repair and maintain the correct function of tissues and organs. Due to their involvement in the embryonic and adult body, they have been suggested to be useable for improving stem cell differentiations in vitro and in vivo. In many studies Hox genes have been found as driving factors in stem cell differentiation towards adipogenesis, in lineages involved in bone and joint formation, mainly chondrogenesis and osteogenesis, in cardiovascular lineages including endothelial and smooth muscle cell differentiations, and in neurogenesis. As life expectancy is rising, the demand for tissue reconstruction continues to increase. Stem cells have become an increasingly popular choice for creating therapies in regenerative medicine due to their self-renewal and differentiation potential. Especially mesenchymal stem cells are used more and more frequently due to their easy handling and accessibility, combined with a low tumorgenicity and little ethical concerns. This review therefore intends to summarize to date known correlations between natural Hox gene expression patterns in body tissues and during the differentiation of various stem cells towards their respective lineages with a major focus on mesenchymal stem cell differentiations. This overview shall help to understand the complex interactions of Hox genes and differentiation processes all over the body as well as in vitro for further improvement of stem cell treatments in future regenerative

  15. Role of Hox genes in stem cell differentiation

    PubMed Central

    Seifert, Anne; Werheid, David F; Knapp, Silvana M; Tobiasch, Edda

    2015-01-01

    Hox genes are an evolutionary highly conserved gene family. They determine the anterior-posterior body axis in bilateral organisms and influence the developmental fate of cells. Embryonic stem cells are usually devoid of any Hox gene expression, but these transcription factors are activated in varying spatial and temporal patterns defining the development of various body regions. In the adult body, Hox genes are among others responsible for driving the differentiation of tissue stem cells towards their respective lineages in order to repair and maintain the correct function of tissues and organs. Due to their involvement in the embryonic and adult body, they have been suggested to be useable for improving stem cell differentiations in vitro and in vivo. In many studies Hox genes have been found as driving factors in stem cell differentiation towards adipogenesis, in lineages involved in bone and joint formation, mainly chondrogenesis and osteogenesis, in cardiovascular lineages including endothelial and smooth muscle cell differentiations, and in neurogenesis. As life expectancy is rising, the demand for tissue reconstruction continues to increase. Stem cells have become an increasingly popular choice for creating therapies in regenerative medicine due to their self-renewal and differentiation potential. Especially mesenchymal stem cells are used more and more frequently due to their easy handling and accessibility, combined with a low tumorgenicity and little ethical concerns. This review therefore intends to summarize to date known correlations between natural Hox gene expression patterns in body tissues and during the differentiation of various stem cells towards their respective lineages with a major focus on mesenchymal stem cell differentiations. This overview shall help to understand the complex interactions of Hox genes and differentiation processes all over the body as well as in vitro for further improvement of stem cell treatments in future regenerative

  16. Mechanism of Action of Two Flavone Isomers Targeting Cancer Cells with Varying Cell Differentiation Status

    PubMed Central

    Parsons, Laura B.; Miller, Gerald E.; Whitted, Crystal; Lynch, Kayla E.; Ramsauer, Robert E.; Patel, Jasmine U.; Wyatt, Jarrett E.; Street, Doris S.; Adams, Carolyn B.; McPherson, Brian; Tsui, Hei Man; Evans, Julie A.; Livesay, Christopher; Torrenegra, Ruben D.; Palau, Victoria E.

    2015-01-01

    Apoptosis can be triggered in two different ways, through the intrinsic or the extrinsic pathway. The intrinsic pathway is mediated by the mitochondria via the release of cytochrome C while the extrinsic pathway is prompted by death receptor signals and bypasses the mitochondria. These two pathways are closely related to cell proliferation and survival signaling cascades, which thereby constitute possible targets for cancer therapy. In previous studies we introduced two plant derived isomeric flavonoids, flavone A and flavone B which induce apoptosis in highly tumorigenic cancer cells of the breast, colon, pancreas, and the prostate. Flavone A displayed potent cytotoxic activity against more differentiated carcinomas of the colon (CaCo-2) and the pancreas (Panc28), whereas flavone B cytotoxic action is observed on poorly differentiated carcinomas of the colon (HCT 116) and pancreas (MIA PaCa). Apoptosis is induced by flavone A in better differentiated colon cancer CaCo-2 and pancreatic cancer Panc 28 cells via the intrinsic pathway by the inhibition of the activated forms of extracellular signal-regulated kinase (ERK) and pS6, and subsequent loss of phosphorylation of Bcl-2 associated death promoter (BAD) protein, while apoptosis is triggered by flavone B in poorly differentiated colon cancer HCT 116 and MIA PaCa pancreatic cancer cells through the extrinsic pathway with the concomitant upregulation of the phosphorylated forms of ERK and c-JUN at serine 73. These changes in protein levels ultimately lead to activation of apoptosis, without the involvement of AKT. PMID:26606169

  17. Glycosylation of Fluorophenols by Plant Cell Cultures

    PubMed Central

    Shimoda, Kei; Kubota, Naoji; Kondo, Yoko; Sato, Daisuke; Hamada, Hiroki

    2009-01-01

    Fluoroaromatic compounds are used as agrochemicals and released into environment as pollutants. Glycosylation of 2-, 3-, and 4-fluorophenols using plant cell cultures of Nicotiana tabacum was investigated to elucidate their potential to metabolize these compounds. Cultured N. tabacum cells converted 2-fluorophenol into its β-glucoside (60%) and β-gentiobioside (10%). 4-Fluorophenol was also glycosylated to its β-glucoside (32%) and β-gentiobioside (6%) by N. tabacum cells. On the other hand, N. tabacum glycosylated 3-fluorophenol to β-glucoside (17%). PMID:19564930

  18. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation

    PubMed Central

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose. PMID:28072818

  19. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation.

    PubMed

    Marroquin-Guzman, Margarita; Sun, Guangchao; Wilson, Richard A

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose.

  20. Epidermal cell patterning and differentiation throughout the apical-basal axis of the seedling.

    PubMed

    Serna, Laura

    2005-08-01

    The idea of common pathways guiding different fates is an emerging concept in plant development, and epidermal cell-fate specification in Arabidopsis thaliana is an excellent example to illustrate it. In the root epidermis, both hair patterning and differentiation depend on a complex interaction between both negative (WER, TTG, GL3, EGL3, and GL2) and positive (CPC, TRY, and ETC1) regulators of hair cell fate. These regulators pattern and differentiate hairs through a bi-directional signalling mechanism. The same molecular components (WER, TTG, GL3, EGL3, and GL2) seem to be involved in the patterning of stomata in the embryonic stem. However, the possible role of CPC, TRY, and ETC1 on stomatal patterning and/or differentiation has not been studied, questioning whether they, and the underlying bi-directional mechanism, guide patterning formation and differentiation in the hypocotyl.

  1. Alpha-adrenergic blocker mediated osteoblastic stem cell differentiation

    SciTech Connect

    Choi, Yoon Jung; Lee, Jue Yeon; Lee, Seung Jin; Chung, Chong-Pyoung; Park, Yoon Jeong

    2011-12-16

    Highlights: Black-Right-Pointing-Pointer Doxazocin directly up-regulated bone metabolism at a low dose. Black-Right-Pointing-Pointer Doxazocin induced osteoblastic stem cell differentiation without affecting cell proliferation. Black-Right-Pointing-Pointer This osteogenic stem cell differentiation is mediated by ERK-signal dependent pathway. -- Abstract: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinically used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor {gamma}, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and

  2. Compartmentalized function through cell differentiation in filamentous cyanobacteria.

    PubMed

    Flores, Enrique; Herrero, Antonia

    2010-01-01

    Within the wide biodiversity that is found in the bacterial world, Cyanobacteria represents a unique phylogenetic group that is responsible for a key metabolic process in the biosphere - oxygenic photosynthesis - and that includes representatives exhibiting complex morphologies. Many cyanobacteria are multicellular, growing as filaments of cells in which some cells can differentiate to carry out specialized functions. These differentiated cells include resistance and dispersal forms as well as a metabolically specialized form that is devoted to N(2) fixation, known as the heterocyst. In this Review we address cyanobacterial intercellular communication, the supracellular structure of the cyanobacterial filament and the basic principles that govern the process of heterocyst differentiation.

  3. Dendritic cell MST1 inhibits Th17 differentiation

    PubMed Central

    Li, Chunxiao; Bi, Yujing; Li, Yan; Yang, Hui; Yu, Qing; Wang, Jian; Wang, Yu; Su, Huilin; Jia, Anna; Hu, Ying; Han, Linian; Zhang, Jiangyuan; Li, Simin; Tao, Wufan; Liu, Guangwei

    2017-01-01

    Although the differentiation of CD4+T cells is widely studied, the mechanisms of antigen-presenting cell-dependent T-cell modulation are unclear. Here, we investigate the role of dendritic cell (DC)-dependent T-cell differentiation in autoimmune and antifungal inflammation and find that mammalian sterile 20-like kinase 1 (MST1) signalling from DCs negatively regulates IL-17 producing-CD4+T helper cell (Th17) differentiation. MST1 deficiency in DCs increases IL-17 production by CD4+T cells, whereas ectopic MST1 expression in DCs inhibits it. Notably, MST1-mediated DC-dependent Th17 differentiation regulates experimental autoimmune encephalomyelitis and antifungal immunity. Mechanistically, MST1-deficient DCs promote IL-6 secretion and regulate the activation of IL-6 receptor α/β and STAT3 in CD4+T cells in the course of inducing Th17 differentiation. Activation of the p38 MAPK signal is responsible for IL-6 production in MST1-deficient DCs. Thus, our results define the DC MST1–p38MAPK signalling pathway in directing Th17 differentiation. PMID:28145433

  4. Structural properties of scaffolds: Crucial parameters towards stem cells differentiation

    PubMed Central

    Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Tian, Lingling; Shamirzaei-Jeshvaghani, Elham; Dehghani, Leila; Ramakrishna, Seeram

    2015-01-01

    Tissue engineering is a multidisciplinary field that applies the principles of engineering and life-sciences for regeneration of damaged tissues. Stem cells have attracted much interest in tissue engineering as a cell source due to their ability to proliferate in an undifferentiated state for prolonged time and capability of differentiating to different cell types after induction. Scaffolds play an important role in tissue engineering as a substrate that can mimic the native extracellular matrix and the properties of scaffolds have been shown to affect the cell behavior such as the cell attachment, proliferation and differentiation. Here, we focus on the recent reports that investigated the various aspects of scaffolds including the materials used for scaffold fabrication, surface modification of scaffolds, topography and mechanical properties of scaffolds towards stem cells differentiation effect. We will present a more detailed overview on the effect of mechanical properties of scaffolds on stem cells fate. PMID:26029344

  5. Regulatory T cells inhibit CD34+ cell differentiation into NK cells by blocking their proliferation

    PubMed Central

    Pedroza-Pacheco, Isabela; Shah, Divya; Domogala, Anna; Luevano, Martha; Blundell, Michael; Jackson, Nicola; Thrasher, Adrian; Madrigal, Alejandro; Saudemont, Aurore

    2016-01-01

    Graft versus Host Disease (GvHD) remains one of the main complications after hematopoietic stem cell transplantation (HSCT). Due to their ability to suppress effector cells, regulatory T cells (Tregs) have been proposed as a cellular therapy to prevent GvHD, however they also inhibit the functions of natural killer (NK) cells, key effectors of the Graft versus Leukemia effect. In this study, we have explored whether a Tregs therapy will also impact on NK cell differentiation. Using an in vitro model of hematopoietic stem cell (HSC) differentiation into NK cells, we found that activated Tregs led to a 90% reduction in NK cell numbers when added at the time of commitment to the NK cell lineage. This effect was contact dependent and was reversible upon Tregs depletion. The few NK cells that developed in these cultures were mature and exhibited normal functions. Furthermore, adoptive transfer of activated Tregs in rag-/- γc-/- mice abrogated HSC differentiation into NK cells thus confirming our in vitro findings. Collectively, these results demonstrate for the first time that activated Tregs can inhibit NK cell differentiation from HSC under specific conditions. PMID:26915707

  6. Regulatory T cells inhibit CD34+ cell differentiation into NK cells by blocking their proliferation.

    PubMed

    Pedroza-Pacheco, Isabela; Shah, Divya; Domogala, Anna; Luevano, Martha; Blundell, Michael; Jackson, Nicola; Thrasher, Adrian; Madrigal, Alejandro; Saudemont, Aurore

    2016-02-26

    Graft versus Host Disease (GvHD) remains one of the main complications after hematopoietic stem cell transplantation (HSCT). Due to their ability to suppress effector cells, regulatory T cells (Tregs) have been proposed as a cellular therapy to prevent GvHD, however they also inhibit the functions of natural killer (NK) cells, key effectors of the Graft versus Leukemia effect. In this study, we have explored whether a Tregs therapy will also impact on NK cell differentiation. Using an in vitro model of hematopoietic stem cell (HSC) differentiation into NK cells, we found that activated Tregs led to a 90% reduction in NK cell numbers when added at the time of commitment to the NK cell lineage. This effect was contact dependent and was reversible upon Tregs depletion. The few NK cells that developed in these cultures were mature and exhibited normal functions. Furthermore, adoptive transfer of activated Tregs in rag(-/-) γc(-/-) mice abrogated HSC differentiation into NK cells thus confirming our in vitro findings. Collectively, these results demonstrate for the first time that activated Tregs can inhibit NK cell differentiation from HSC under specific conditions.

  7. Muse Cells Derived from Dermal Tissues Can Differentiate into Melanocytes.

    PubMed

    Tian, Ting; Zhang, Ru-Zhi; Yang, Yu-Hua; Liu, Qi; Li, Di; Pan, Xiao-Ru

    2017-02-07

    The objective of the authors has been to obtain multilineage-differentiating stress-enduring cells (Muse cells) from primary cultures of dermal fibroblasts, identify their pluripotency, and detect their ability to differentiate into melanocytes. The distribution of SSEA-3-positive cells in human scalp skin was assessed by immunohistochemistry, and the distribution of Oct4, Sox2, Nanog, and SSEA-3-positive cells was determined by immunofluorescence staining. The expression levels of Sox2, Oct4, hKlf4, and Nanog mRNAs and proteins in Muse cells were determined by reverse transcription polymerase chain reaction (RT-PCR) analyses and Western blots, respectively. These Muse cells differentiated into melanocytes in differentiation medium. The SSEA-3-positive cells were scattered in the basement membrane zone and the dermis, with comparatively more in the sebaceous glands, vascular and sweat glands, as well as the outer root sheath of hair follicles, the dermal papillae, and the hair bulbs. Muse cells, which have the ability to self-renew, were obtained from scalp dermal fibroblasts by flow cytometry sorting with an anti-SSEA-3 antibody. The results of RT-PCR, Western blot, and immunofluorescence staining showed that the expression levels of Oct4, Nanog, Sox2, and Klf4 mRNAs and proteins in Muse cells were significantly different from their parental dermal fibroblasts. Muse cells differentiated into melanocytes when cultured in melanocyte differentiation medium, and the Muse cell-derived melanocytes expressed the melanocyte-specific marker HMB45. Muse cells could be obtained by flow cytometry from primary cultures of scalp dermal fibroblasts, which possessed the ability of pluripotency and self-renewal, and could differentiate into melanocytes in vitro.

  8. 3. Right side of Zinc Plant, from Cell Room midpoint ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Right side of Zinc Plant, from Cell Room midpoint to Plant Office (foreground) and #5 Roaster and Concentrate Handling (background). View is to the east. - Sullivan Electrolytic Zinc Plant, Government Gulch, Kellogg, Shoshone County, ID

  9. Differentiation of dental pulp stem cells into neuron-like cells in serum-free medium.

    PubMed

    Zainal Ariffin, Shahrul Hisham; Kermani, Shabnam; Zainol Abidin, Intan Zarina; Megat Abdul Wahab, Rohaya; Yamamoto, Zulham; Senafi, Sahidan; Zainal Ariffin, Zaidah; Abdul Razak, Mohamad

    2013-01-01

    Dental pulp tissue contains dental pulp stem cells (DPSCs). Dental pulp cells (also known as dental pulp-derived mesenchymal stem cells) are capable of differentiating into multilineage cells including neuron-like cells. The aim of this study was to examine the capability of DPSCs to differentiate into neuron-like cells without using any reagents or growth factors. DPSCs were isolated from teeth extracted from 6- to 8-week-old mice and maintained in complete medium. The cells from the fourth passage were induced to differentiate by culturing in medium without serum or growth factors. RT-PCR molecular analysis showed characteristics of Cd146(+) , Cd166(+) , and Cd31(-) in DPSCs, indicating that these cells are mesenchymal stem cells rather than hematopoietic stem cells. After 5 days of neuronal differentiation, the cells showed neuron-like morphological changes and expressed MAP2 protein. The activation of Nestin was observed at low level prior to differentiation and increased after 5 days of culture in differentiation medium, whereas Tub3 was activated only after 5 days of neuronal differentiation. The proliferation of the differentiated cells decreased in comparison to that of the control cells. Dental pulp stem cells are induced to differentiate into neuron-like cells when cultured in serum- and growth factor-free medium.

  10. Osteogenic differentiation capacity of porcine dental follicle progenitor cells.

    PubMed

    Tsuchiya, Shuhei; Ohshima, Satoshi; Yamakoshi, Yasuo; Simmer, James P; Honda, Masaki J

    2010-06-01

    This study examined the effect of extracellular matrix (ECM) on the osteogenic differentiation capacity and osteogenesis of dental follicle cells. Single cell-derived porcine dental follicle cells (DFC-I) obtained at the early stage of crown formation in tooth were subcultured and characterized using periodontal ligament cells (PDLC) and bone marrow-derived mesenchymal stem cells (BMSC) as comparison cell populations. The effect of ECM constituents including collagen type I, fibronectin, laminin, and collagen type IV on the differentiation of DFC-1 into osteogenic-lineage cells was evaluated in vitro. In addition, the DFC-1, PDLC, and BMSC populations were compared for osteogenic capacity in vitro by Alizarin red staining and in vivo by transplantation. DFC-I showed different features from PDLC and BMSC. Different components of ECM had different effects on the differentiation of DFC-1 into osteogenic-lineage cells in vitro. Alkaline phosphatase activity and matrix mineralization as early- and late-stage markers of osteogenesis, respectively, supported the differentiation of DFC-1 into osteogenic-related cells in vitro. All three cell types showed equivalent osteogenic capacity in vivo at 4 weeks postoperatively. There were no statistically significant differences among the cell populations with respect to capacity for bone formation. These results suggest a potential application for dental follicle cells in bone-tissue engineering.

  11. Principles and limitations of stable isotopes in differentiating organic and conventional foodstuffs: 1. Plant products.

    PubMed

    Inácio, Caio Teves; Chalk, Phillip Michael; Magalhães, Alberto M T

    2015-01-01

    Among the lighter elements having two or more stable isotopes (H, C, N, O, S), δ(15)N appears to be the most promising isotopic marker to differentiate plant products from conventional and organic farms. Organic plant products vary within a range of δ(15)N values of +0.3 to +14.6%, while conventional plant products range from negative to positive values, i.e. -4.0 to +8.7%. The main factors affecting δ(15)N signatures of plants are N fertilizers, biological N2 fixation, plant organs and plant age. Correlations between mode of production and δ(13)C (except greenhouse tomatoes warmed with natural gas) or δ(34)S signatures have not been established, and δ(2)H and δ(18)O are unsuitable markers due to the overriding effect of climate on the isotopic composition of plant-available water. Because there is potential overlap between the δ(15)N signatures of organic and conventionally produced plant products, δ(15)N has seldom been used successfully as the sole criterion for differentiation, but when combined with complementary analytical techniques and appropriate statistical tools, the probability of a correct identification increases. The use of organic fertilizers by conventional farmers or the marketing of organic produce as conventional due to market pressures are additional factors confounding correct identification. The robustness of using δ(15)N to differentiate mode of production will depend on the establishment of databases that have been verified for individual plant products.

  12. The organelle of differentiation in embryos: the cell state splitter.

    PubMed

    Gordon, Natalie K; Gordon, Richard

    2016-03-10

    The cell state splitter is a membraneless organelle at the apical end of each epithelial cell in a developing embryo. It consists of a microfilament ring and an intermediate filament ring subtending a microtubule mat. The microtubules and microfilament ring are in mechanical opposition as in a tensegrity structure. The cell state splitter is bistable, perturbations causing it to contract or expand radially. The intermediate filament ring provides metastability against small perturbations. Once this snap-through organelle is triggered, it initiates signal transduction to the nucleus, which changes gene expression in one of two readied manners, causing its cell to undergo a step of determination and subsequent differentiation. The cell state splitter also triggers the cell state splitters of adjacent cells to respond, resulting in a differentiation wave. Embryogenesis may be represented then as a bifurcating differentiation tree, each edge representing one cell type. In combination with the differentiation waves they propagate, cell state splitters explain the spatiotemporal course of differentiation in the developing embryo. This review is excerpted from and elaborates on "Embryogenesis Explained" (World Scientific Publishing, Singapore, 2016).

  13. Dedifferentiated fat cells differentiate into osteoblasts in titanium fiber mesh.

    PubMed

    Kishimoto, Naotaka; Momota, Yoshihiro; Hashimoto, Yoshiya; Ando, Kayoko; Omasa, Takeshi; Kotani, Junichiro

    2013-01-01

    Mature adipocyte-derived dedifferentiated fat (DFAT) cells rapidly differentiate into osteoblasts under three-dimensional culture conditions. However, it has not been demonstrated that DFAT cells can differentiate into osteoblasts in a rigid scaffold consisting of titanium fiber mesh (TFM). We examined the proliferation and osteogenic differentiation ability of DFAT cells using TFM as a scaffold. DFAT cells derived from rabbit subcutaneous fat were seeded into TFM and cultured in osteogenic medium containing dexamethasone, L-ascorbic acid 2-phosphate and β-glycerophosphate for 14 days. In scanning electron microscopy (SEM) analysis, well-spread cells covered the titanium fibers on day 3, and appeared to increase in number from day 3 to 7. Numerous globular accretions were found and almost completely covered the fibers on day 14. Cell proliferation, as measured by DNA content in the TFM, was significantly higher on day 7 compared with that of day 1. Osteocalcin and calcium content in the TFM were significantly higher on day 14 compared to those of days 1, 3, and 7, indicating DFAT cells differentiated into osteoblasts. We theorize that globular accretions observed in SEM analysis may be calcified matrix resulting from osteocalcin secreted by osteoblasts binding calcium contained in fetal bovine serum. In this study, we demonstrated that DFAT cells differentiate into osteoblasts and deposit mineralized matrices in TFM. Therefore, the combination of DFAT cells and TFM may be an attractive option for bone tissue engineering.

  14. Differentiation of Spermatogonia Stem Cells into Functional Mature Neurons Characterized with Differential Gene Expression.

    PubMed

    Bojnordi, Maryam Nazm; Azizi, Hossein; Skutella, Thomas; Movahedin, Mansoureh; Pourabdolhossein, Fereshteh; Shojaei, Amir; Hamidabadi, Hatef Ghasemi

    2016-09-19

    Transplantation of embryonic stem cells (ESCs) is a promising therapeutic approach for the treatment of neurodegenerative diseases. However, ESCs are not usable clinically due to immunological and ethical limitations. The identification of an alternative safe cell source opens novel options via autologous transplantation in neuro-regeneration circumventing these problems. Here, we examined the neurogenic capacity of embryonic stem-like cells (ES-like cells) derived from the testis using neural growth factor inducers and utilized them to generate functional mature neurons. The neuronal differentiation of ES-like cells is induced in three stages. Stage 1 is related to embryoid body (EB) formation. To induce neuroprogenitor cells, EBs were cultured in the presence of retinoic acid, N2 supplement and fibroblast growth factor followed by culturing in a neurobasal medium containing B27, N2 supplements for additional 10 days, to allow the maturation and development of neuronal progenitor cells. The neurogenic differentiation was confirmed by immunostaining for markers of mature neurons. The differentiated neurons were positive for Tuj1 and Tau1. Real-time PCR dates indicated the expression of Nestin and Neuro D (neuroprogenitor markers) in induced cells at the second stage of the differentiation protocol. The differentiated mature neurons exhibited the specific neuron markers Map2 and β-tubulin. The functional maturity of neurons was confirmed by an electrophysiological analysis of passive and active neural membrane properties. These findings indicated a differentiation capacity of ES-like cells derived from the testis to functionally mature neurons, which proposes them as a novel cell source for neuroregenerative medicine.

  15. The Therapeutic Potential of Differentiated Lung Cells from Embryonic Stem Cells in Lung Diseases.

    PubMed

    Mokhber Dezfouli, Mohammad Reza; Chaleshtori, Sirous Sadeghian; Dehghan, Mohammad Mehdi; Tavanaeimanesh, Hamid; Baharvand, Hossein; Tahamtani, Yaser

    2017-01-01

    Lung diseases cause great morbidity and mortality. The choice of effective medical treatment is limited and the number of lung diseases are difficult to treat with current treatments. The embryonic stem cells (ESCs) have the potential to differentiate into cell types of all three germinal layers, including lung epithelial cells. So they can be a potential source for new cell therapies for hereditary or acquired diseases of the airways and lungs. One method for treatment of lung diseases is cell therapy and the use of ESCs that can replace the damaged epithelial and endothelial cells. Progress using ESCs has developed slowly for lung regeneration because differentiation of lung cells from ESCs is more difficult as compared to differentiation of other cells. The review studies the therapeutic effects of differentiated lung cells from embryonic stem cells in lung diseases. There are few studies of differentiation of ESCs into a lineage of respiratory and then investigation of this cell in experimental model of lung diseases.

  16. Cross Talk with Hematopoietic Cells Regulates the Endothelial Progenitor Cell Differentiation of CD34 Positive Cells

    PubMed Central

    Lee, Sang-Hun; Jung, Seok-Yun; Kim, Da-Yeon; Kang, Song-Hwa; Yoo, So-Young; Hong, Jong-Kyu; Park, Ji-Hye; Kim, Jung-Hee; Kim, Sung-Wook; Kim, Yeon-Ju; Lee, Sun-Jin; Kim, Hwi-Gon; Asahara, Takayuki

    2014-01-01

    Introduction Despite the crucial role of endothelial progenitor cells (EPCs) in vascular regeneration, the specific interactions between EPCs and hematopoietic cells remain unclear. Methods In EPC colony forming assays, we first demonstrated that the formation of EPC colonies was drastically increased in the coculture of CD34+ and CD34− cells, and determined the optimal concentrations of CD34+ cells and CD34− cells for spindle-shaped EPC differentiation. Results Functionally, the coculture of CD34+ and CD34− cells resulted in a significant enhancement of adhesion, tube formation, and migration capacity compared with culture of CD34+ cells alone. Furthermore, blood flow recovery and capillary formation were remarkably increased by the coculture of CD34+ and CD34− cells in a murine hind-limb ischemia model. To elucidate further the role of hematopoietic cells in EPC differentiation, we isolated different populations of hematopoietic cells. T lymphocytes (CD3+) markedly accelerated the early EPC status of CD34+ cells, while macrophages (CD11b+) or megakaryocytes (CD41+) specifically promoted large EPC colonies. Conclusion Our results suggest that specific populations of hematopoietic cells play a role in the EPC differentiation of CD34+ cells, a finding that may aid in the development of a novel cell therapy strategy to overcome the quantitative and qualitative limitations of EPC therapy. PMID:25166961

  17. Differential radiosensitivity among B cell subpopulations

    SciTech Connect

    Riggs, J.E.

    1988-01-01

    The selective radiosensitivity of sIgM >> sIgD marginal zone B cells is associated with the selective loss of B cell function. The simultaneous restoration of impaired function and recovery of these cells with time supports this premise. B cell recovery, delayed one week after irradiation, is in progress at two weeks, and virtually complete by three weeks. XID mice reveal similar recovery kinetics although there are fewer recovering cells and these bear reduced levels of Ia. This observation represents additional evidence that xid B cells are distinct from those of normal mice. The simultaneous loss, and concurrent recovery, of sIgM >> sIgD B cells and TI-2 responsiveness in irradiated mice suggests the existence of a unique B cell subpopulation possessing both phenotypes. Additional support for this hypothesis is provided by demonstrating that splenocytes, depleted of IgD{sup +} cells adoptively reconstitute this response in XID mice. The peritoneal B cell pool, which, compared to the spleen, consist of increased numbers of sIgM >> sIgD B cells, is shown to be a source of radiosensitive B cells that are TI-2 responsive. These observations represent additional evidence for an association between sIgM >> sIgD B cells and TI-2 responsiveness.

  18. COMPUTATION MODELING OF TCDD DISRUPTION OF B CELL TERMINAL DIFFERENTIATION

    EPA Science Inventory

    In this study, we established a computational model describing the molecular circuit underlying B cell terminal differentiation and how TCDD may affect this process by impinging upon various molecular targets.

  19. A Role of TDIF Peptide Signaling in Vascular Cell Differentiation is Conserved Among Euphyllophytes

    PubMed Central

    Hirakawa, Yuki; Bowman, John L.

    2015-01-01

    Peptide signals mediate a variety of cell-to-cell communication crucial for plant growth and development. During Arabidopsis thaliana vascular development, a CLE (CLAVATA3/EMBRYO SURROUNDING REGION-related) family peptide hormone, TDIF (tracheary element differentiation inhibitory factor), regulates procambial cell fate by its inhibitory activity on xylem differentiation. To address if this activity is conserved among vascular plants, we performed comparative analyses of TDIF signaling in non-flowering vascular plants (gymnosperms, ferns and lycophytes). We identified orthologs of TDIF/CLE as well as its receptor TDR/PXY (TDIF RECEPTOR/PHLOEM INTERCALATED WITH XYLEM) in Ginkgo biloba, Adiantum aethiopicum, and Selaginella kraussiana by RACE-PCR. The predicted TDIF peptide sequences in seed plants and ferns were identical to that of A. thaliana TDIF. We examined the effects of exogenous CLE peptide-motif sequences of TDIF in these species. We found that liquid culturing of dissected leaves or shoots was useful for examining TDIF activity during vascular development. TDIF treatment suppressed xylem/tracheary element differentiation of procambial cells in G. biloba and A. aethiopicum leaves. In contrast, neither TDIF nor putative endogenous TDIF inhibited xylem differentiation in developing shoots and rhizophores of S. kraussiana. These data suggest that activity of TDIF in vascular development is conserved among extant euphyllophytes. In addition to the conserved function, via liquid culturing of its bulbils, we found a novel inhibitory activity on root growth in the fern Asplenium × lucrosum suggesting lineage-specific co-option of peptide signaling occurred during the evolution of vascular plant organs. PMID:26635860

  20. Wound healing response and xylem differentiation in tobacco plants over-expressing a fungal endopolygalacturonase is mediated by copper amine oxidase activity.

    PubMed

    Cona, Alessandra; Tisi, Alessandra; Ghuge, Sandip Annasaheb; Franchi, Stefano; De Lorenzo, Giulia; Angelini, Riccardo

    2014-09-01

    In this work, we have investigated the involvement of copper amine oxidase (CuAO; EC 1.4.3.21) in wound healing and xylem differentiation of Nicotiana tabacum plants over-expressing a fungal endopolygalacturonase (PG plants), which show constitutively activated defence responses. In petioles and stems of PG plants, we found higher CuAO activity and lower polyamine (PA) levels, particularly putrescine (Put), with respect to wild-type (WT) plants. Upon wounding, a more intense autofluorescence of cell wall phenolics was observed in correspondence of wound surface, extending to epidermis and cortical parenchima only in PG plants. This response was mostly dependent on CuAO activity, as suggested by the reversion of autofluorescence upon supply of 2-bromoethylamine (2-BrEt), a CuAO specific inhibitor. Moreover, in unwounded plants, histochemical analysis revealed a tissue-specific expression of the enzyme in the vascular cambium and neighboring derivative cells of both petioles and stems of PG plants, whereas the corresponding WT tissues appeared unstained or faintly stained. A higher histochemical CuAO activity was also observed in xylem cells of PG plants as compared to WT xylem tissues suggesting a peculiar role of CuAO activity in xylem differentiation in PG plants. Indeed, roots of PG plants exhibited early xylem differentiation, a phenotype consistent with both the higher CuAO and the lower Put levels observed and supported by the 2-BrEt-mediated reversion of early root xylem differentiation and H2O2 accumulation. These results strongly support the relevance of PA-catabolism derived H2O2 in defence responses, such as those signaled by a compromised status of cell wall pectin integrity.

  1. Differentiation of germinal and somatic cells in Volvox carteri.

    PubMed

    Schmitt, Rüdiger

    2003-12-01

    Volvox carteri is a spherical alga with a complete division of labor between around 2000 biflagellate somatic cells and 16 asexual reproductive cells (gonidia). It provides an attractive system for studying how a molecular genetic program for cell-autonomous differentiation is encoded within the genome. Three types of genes have been identified as key players in germ-soma differentiation: a set of gls genes that act in the embryo to shift cell-division planes, resulting in asymmetric divisions that set apart the large-small sister-cell pairs; a set of lag genes that act in the large gonidial initials to prevent somatic differentiation; and the regA gene, which acts in the small somatic initials to prevent reproductive development. Somatic-cell-specific expression of regA is controlled by intronic enhancer and silencer elements.

  2. How to let go: pectin and plant cell adhesion

    PubMed Central

    Daher, Firas Bou; Braybrook, Siobhan A.

    2015-01-01

    Plant cells do not, in general, migrate. They maintain a fixed position relative to their neighbors, intimately linked through growth and differentiation. The mediator of this connection, the pectin-rich middle lamella, is deposited during cell division and maintained throughout the cell’s life to protect tissue integrity. The maintenance of adhesion requires cell wall modification and is dependent on the actin cytoskeleton. There are developmental processes that require cell separation, such as organ abscission, dehiscence, and ripening. In these instances, the pectin-rich middle lamella must be actively altered to allow cell separation, a process which also requires cell wall modification. In this review, we will focus on the role of pectin and its modification in cell adhesion and separation. Recent insights gained in pectin gel mechanics will be discussed in relation to existing knowledge of pectin chemistry as it relates to cell adhesion. As a whole, we hope to begin defining the physical mechanisms behind a cells’ ability to hang on, and how it lets go. PMID:26236321

  3. Differential spheroid formation by oral cancer cells.

    PubMed

    Lee, Carlin; Lee, Casey; Atakilit, Amha; Siu, Amanda; Ramos, Daniel M

    2014-12-01

    Squamous cell carcinomas (SCC) make up 96% of all oral cancers. Most laboratory SCC studies grow cells as a monolayer, which does not accurately represent the disease in vivo. We used a more relevant multicellular spheroid (MCS) model to study this disease. The SCC9β6KDFyn cell line, which expresses full-length β6 and a kinase dead Fyn formed the largest MCS. Cell adhesive properties are dynamic and N-cadherin was increased in the largest MCS. c-Raf mediates the survival of tumor cells and was consistently expressed both in monolayers and in the MCS by SCC9β6D1 cells which lack the β6 cytoplasmic tail and, do not activate Fyn. SCC9β6KDFyn cells also express high levels of c-Raf when grown as spheroids in which Fyn suppression stimulates MCS formation. Tumor microenvironment and growth patterns modulate cell behavior and suppression of Fyn kinase may promote MCS growth.

  4. Fuel cell power plant economic and operational considerations

    NASA Technical Reports Server (NTRS)

    Lance, J. R.

    1984-01-01

    Fuel cell power plants intended for electric utility and cogeneration applications are now in the design and construction stage. This paper describes economic and operational considerations being used in the development and design of plants utilizing air cooled phosphoric acid fuel cells. Fuel cell power plants have some unique characteristics relative to other types of power plants. As a result it was necessary to develop specific definitions of the fuel cell power plant characteristics in order to perform cost of electricity calculations. This paper describes these characteristics and describes the economic analyses used in the Westinghouse fuel cell power plant program.

  5. Isomaltulose is actively metabolized in plant cells.

    PubMed

    Wu, Luguang; Birch, Robert G

    2011-12-01

    Isomaltulose is a structural isomer of sucrose (Suc). It has been widely used as a nonmetabolized sugar in physiological studies aimed at better understanding the regulatory roles and transport of sugars in plants. It is increasingly used as a nutritional human food, with some beneficial properties including low glycemic index and acariogenicity. Cloning of genes for Suc isomerases opened the way for direct commercial production in plants. The understanding that plants lack catabolic capabilities for isomaltulose indicated a possibility of enhanced yields relative to Suc. However, this understanding was based primarily on the treatment of intact cells with exogenous isomaltulose. Here, we show that sugarcane (Saccharum interspecific hybrids), like other tested plants, does not readily import or catabolize extracellular isomaltulose. However, among intracellular enzymes, cytosolic Suc synthase (in the breakage direction) and vacuolar soluble acid invertase (SAI) substantially catabolize isomaltulose. From kinetic studies, the specificity constant of SAI for isomaltulose is about 10% of that for Suc. Activity varied against other Suc isomers, with V(max) for leucrose about 6-fold that for Suc. SAI activities from other plant species varied substantially in substrate specificity against Suc and its isomers. Therefore, in physiological studies, the blanket notion of Suc isomers including isomaltulose as nonmetabolized sugars must be discarded. For example, lysis of a few cells may result in the substantial hydrolysis of exogenous isomaltulose, with profound downstream signal effects. In plant biotechnology, different V(max) and V(max)/K(m) ratios for Suc isomers may yet be exploited, in combination with appropriate developmental expression and compartmentation, for enhanced sugar yields.

  6. T Cell Receptor Signaling in the Control of Regulatory T Cell Differentiation and Function

    PubMed Central

    Li, Ming O.; Rudensky, Alexander Y.

    2016-01-01

    Regulatory T cells (TReg cells), a specialized T cell lineage, have a pivotal function in the control of self-tolerance and inflammatory responses. Recent studies have revealed a discrete mode of TCR signaling that regulates Treg cell differentiation, maintenance and function and that impacts on gene expression, metabolism, cell adhesion and migration of these cells. Here, we discuss the emerging understanding of TCR-guided differentiation of Treg cells in the context of their function in health and disease. PMID:27026074

  7. Mouse differentiating spermatogonia can generate germinal stem cells in vivo.

    PubMed

    Barroca, Vilma; Lassalle, Bruno; Coureuil, Mathieu; Louis, Jean Paul; Le Page, Florence; Testart, Jacques; Allemand, Isabelle; Riou, Lydia; Fouchet, Pierre

    2009-02-01

    In adults, stem cells are responsible for the maintenance of many actively renewing tissues, such as haematopoietic, skin, gut and germinal tissues. These stem cells can self-renew or be committed to becoming progenitors. Stem-cell commitment is thought to be irreversible but in male and female Drosophila melanogaster, it was shown recently that differentiating germ cells can revert to functional stem cells that can restore germinal lineage. Whether progenitors are also able to generate stem cells in mammals remains unknown. Here we show that purified mouse spermatogonial progenitors committed to differentiation can generate functional germinal stem cells that can repopulate germ-cell-depleted testes when transplanted into adult mice. We found that GDNF, a key regulator of the stem-cell niche, and FGF2 are able to reprogram in vitro spermatogonial progenitors for reverse differentiation. This study supports the emerging concept that the stem-cell identity is not restricted in adults to a definite pool of cells that self-renew, but that stemness could be acquired by differentiating progenitors after tissue injury and throughout life.

  8. Isolation of plant cell wall proteins.

    PubMed

    Jamet, Elisabeth; Boudart, Georges; Borderies, Giséle; Charmont, Stephane; Lafitte, Claude; Rossignol, Michel; Canut, Herve; Pont-Lezica, Rafael

    2008-01-01

    The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific drawbacks: (1) the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP) during the isolation procedure; (2) polysaccharide networks of cellulose, hemicelluloses, and pectins form potential traps for contaminants such as intracellular proteins; (3) the presence of proteins interacting in many different ways with the polysaccharide matrix require different procedures to elute them from the cell wall. Three categories of CWP are distinguished: labile proteins that have little or no interactions with cell wall components, weakly bound proteins extractable with salts, and strongly bound proteins. Two alternative protocols are decribed for cell wall proteomics: (1) nondestructive techniques allowing the extraction of labile or weakly bound CWP without damaging the plasma membrane; (2) destructive techniques to isolate cell walls from which weakly or strongly bound CWP can be extracted. These protocols give very low levels of contamination by intracellular proteins. Their application should lead to a realistic view of the cell wall proteome at least for labile and weakly bound CWP extractable by salts.

  9. Pituitary cell differentiation from stem cells and other cells: toward restorative therapy for hypopituitarism?

    PubMed

    Willems, Christophe; Vankelecom, Hugo

    2014-01-01

    The pituitary gland, key regulator of our endocrine system, produces multiple hormones that steer essential physiological processes. Hence, deficient pituitary function (hypopituitarism) leads to severe disorders. Hypopituitarism can be caused by defective embryonic development, or by damage through tumor growth/resection and traumatic brain injury. Lifelong hormone replacement is needed but associated with significant side effects. It would be more desirable to restore pituitary tissue and function. Recently, we showed that the adult (mouse) pituitary holds regenerative capacity in which local stem cells are involved. Repair of deficient pituitary may therefore be achieved by activating these resident stem cells. Alternatively, pituitary dysfunction may be mended by cell (replacement) therapy. The hormonal cells to be transplanted could be obtained by (trans-)differentiating various kinds of stem cells or other cells. Here, we summarize the studies on pituitary cell regeneration and on (trans-)differentiation toward hormonal cells, and speculate on restorative therapies for pituitary deficiency.

  10. Regeneration niche differentiates functional strategies of desert woody plant species

    PubMed Central

    Briggs, John M.

    2010-01-01

    Plant communities vary dramatically in the number and relative abundance of species that exhibit facilitative interactions, which contributes substantially to variation in community structure and dynamics. Predicting species’ responses to neighbors based on readily measurable functional traits would provide important insight into the factors that structure plant communities. We measured a suite of functional traits on seedlings of 20 species and mature plants of 54 species of shrubs from three arid biogeographic regions. We hypothesized that species with different regeneration niches—those that require nurse plants for establishment (beneficiaries) versus those that do not (colonizers)—are functionally different. Indeed, seedlings of beneficiary species had lower relative growth rates, larger seeds and final biomass, allocated biomass toward roots and height at a cost to leaf mass fraction, and constructed costly, dense leaf and root tissues relative to colonizers. Likewise at maturity, beneficiaries had larger overall size and denser leaves coupled with greater water use efficiency than colonizers. In contrast to current hypotheses that suggest beneficiaries are less “stress-tolerant” than colonizers, beneficiaries exhibited conservative functional strategies suited to persistently dry, low light conditions beneath canopies, whereas colonizers exhibited opportunistic strategies that may be advantageous in fluctuating, open microenvironments. In addition, the signature of the regeneration niche at maturity indicates that facilitation expands the range of functional diversity within plant communities at all ontogenetic stages. This study demonstrates the utility of specific functional traits for predicting species’ regeneration niches in hot deserts, and provides a framework for studying facilitation in other severe environments. Electronic supplementary material The online version of this article (doi:10.1007/s00442-010-1741-y) contains supplementary

  11. DIRECTED DIFFERENTIATION OF EMBRYONIC STEM CELLS INTO BLADDER TISSUE

    PubMed Central

    Oottamasathien, Siam; Wang, YongQing; Williams, Karin; Franco, Omar E.; Wills, Marcia L.; Thomas, John C.; Saba, Katrina; Sharif-Afshar, Ali-Reza; Makari, John H.; Bhowmick, Neil A; DeMarco, Romano T.; Hipkens, Susan; Magnuson, Mark; Brock, John W.; Hayward, Simon W.; Pope, John C.; Matusik, Robert J.

    2007-01-01

    Manipulatable models of bladder development which interrogate specific pathways are badly needed. Such models will allow a systematic investigation of the multitude of pathologies which result from developmental defects of the urinary bladder. In the present communication, we describe a model in which mouse embryonic stem (ES) cells are directed to differentiate to form bladder tissue by specific interactions with fetal bladder mesenchyme. This model allows us to visualize the various stages in the differentiation of urothelium from ES cells, including the commitment to an endodermal cell lineage, with the temporal profile characterized by examining the induction of specific endodermal transcription factors (Foxa1 and Foxa2). In addition, final functional urothelial differentiation was characterized by examining uroplakin expression. It is well established that ES cells will spontaneously develop teratomas when grown within immunocompromised mouse hosts. We determined the specific mesenchymal to ES cell ratios necessary to dictate organ-specific differentiation while completely suppressing teratomatous growth. Embryonic mesenchyme is well established as an inductive tissue which dictates organ-specific programming of epithelial tissues. The present study demonstrates that embryonic bladder mesenchyme can also steer ES cells towards developing specific endodermal derived urothelium. These approaches allow us to capture specific stages of stem cell differentiation and to better define stem cell hierarchies. PMID:17289017

  12. Hematopoietic myeloid cell differentiation diminishes nucleotide excision repair.

    PubMed

    Aoki, Yuki; Sato, Ayako; Mizutani, Shuki; Takagi, Masatoshi

    2014-09-01

    Myeloid cell differentiation is the process by which stem cells develop into mature monocytes or granulocytes. This process is achieved by the sequential activation of variety of genes. Disruption of this process can result in immunodeficiency, bone marrow failure syndrome, or leukemia. Acute promyelocytic leukemia (APL) is characterized by the t(15;17) translocation and can be treated by a combination of all-trans retinoic acid (ATRA) and anthracycline. This treatment can induce leukemic cell differentiation, leading to extremely high remission rates. XAB2, a molecule involved in nucleotide excision repair (NER), is downregulated during granulocyte differentiation and shows reduced expression in NB4 APL-derived cells in vitro. Differentiation of APL by ATRA treatment reduced XAB2 expression levels in vivo. These observations suggest that cellular differentiation is associated with reduced NER activity and provides new insights into combined differentiation induction. NB4 cells were more susceptible than the immature myeloid leukemic cell lines, Kasumi-3 and Kasumi-1, to the DNA interstrand crosslinking agent cisplatin.

  13. BMP2 induces chondrogenic differentiation, osteogenic differentiation and endochondral ossification in stem cells.

    PubMed

    Zhou, Nian; Li, Qi; Lin, Xin; Hu, Ning; Liao, Jun-Yi; Lin, Liang-Bo; Zhao, Chen; Hu, Zhen-Ming; Liang, Xi; Xu, Wei; Chen, Hong; Huang, Wei

    2016-10-01

    Bone morphogenetic protein 2 (BMP2), a member of the transforming growth factor-β (TGF-β) super-family, is one of the main chondrogenic growth factors involved in cartilage regeneration. BMP2 is known to induce chondrogenic differentiation in various types of stem cells in vitro. However, BMP2 also induces osteogenic differentiation and endochondral ossification in mesenchymal stem cells (MSCs). Although information regarding BMP2-induced chondrogenic and osteogenic differentiation within the same system might be essential for cartilage tissue engineering, few studies concerning these issues have been conducted. In this study, BMP2 was identified as a regulator of chondrogenic differentiation, osteogenic differentiation and endochondral bone formation within the same system. BMP2 was used to regulate chondrogenic and osteogenic differentiation in stem cells within the same culture system in vitro and in vivo. Any changes in the differentiation markers were assessed. BMP2 was found to induce chondrogenesis and osteogenesis in vitro via the expression of Sox9, Runx2 and its downstream markers. According to the results of the subcutaneous stem cell implantation studies, BMP2 not only induced cartilage formation but also promoted endochondral ossification during ectopic bone/cartilage formation. In fetal limb cultures, BMP2 promoted chondrocyte hypertrophy and endochondral ossification. Our data reveal that BMP2 can spontaneously induce chondrogenic differentiation, osteogenic differentiation and endochondral bone formation within the same system. Thus, BMP2 can be used in cartilage tissue engineering to regulate cartilage formation but has to be properly regulated for cartilage tissue engineering in order to retain the cartilage phenotype.

  14. Differentiation of Symbiotic Cells and Endosymbionts in Medicago truncatula Nodulation Are Coupled to Two Transcriptome-Switches

    PubMed Central

    Maunoury, Nicolas; Redondo-Nieto, Miguel; Bourcy, Marie; Van de Velde, Willem; Alunni, Benoit; Laporte, Philippe; Durand, Patricia; Agier, Nicolas; Marisa, Laetitia; Vaubert, Danièle; Delacroix, Hervé; Duc, Gérard; Ratet, Pascal; Aggerbeck, Lawrence; Kondorosi, Eva; Mergaert, Peter

    2010-01-01

    The legume plant Medicago truncatula establishes a symbiosis with the nitrogen-fixing bacterium Sinorhizobium meliloti which takes place in root nodules. The formation of nodules employs a complex developmental program involving organogenesis, specific cellular differentiation of the host cells and the endosymbiotic bacteria, called bacteroids, as well as the specific activation of a large number of plant genes. By using a collection of plant and bacterial mutants inducing non-functional, Fix− nodules, we studied the differentiation processes of the symbiotic partners together with the nodule transcriptome, with the aim of unravelling links between cell differentiation and transcriptome activation. Two waves of transcriptional reprogramming involving the repression and the massive induction of hundreds of genes were observed during wild-type nodule formation. The dominant features of this “nodule-specific transcriptome” were the repression of plant defense-related genes, the transient activation of cell cycle and protein synthesis genes at the early stage of nodule development and the activation of the secretory pathway along with a large number of transmembrane and secretory proteins or peptides throughout organogenesis. The fifteen plant and bacterial mutants that were analyzed fell into four major categories. Members of the first category of mutants formed non-functional nodules although they had differentiated nodule cells and bacteroids. This group passed the two transcriptome switch-points similarly to the wild type. The second category, which formed nodules in which the plant cells were differentiated and infected but the bacteroids did not differentiate, passed the first transcriptome switch but not the second one. Nodules in the third category contained infection threads but were devoid of differentiated symbiotic cells and displayed a root-like transcriptome. Nodules in the fourth category were free of bacteria, devoid of differentiated symbiotic

  15. How do plant cell walls extend?

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1993-01-01

    This article briefly summarizes recent work that identifies the biophysical and biochemical processes that give rise to the extension of plant cell walls. I begin with the biophysical notion of stress relaxation of the wall and follow with recent studies of wall enzymes thought to catalyze wall extension and relaxation. Readers should refer to detailed reviews for more comprehensive discussion of earlier literature (Taiz, 1984; Carpita and Gibeaut, 1993; Cosgrove, 1993).

  16. Epigenetic control of myeloid cell differentiation, identity and function.

    PubMed

    Álvarez-Errico, Damiana; Vento-Tormo, Roser; Sieweke, Michael; Ballestar, Esteban

    2015-01-01

    Myeloid cells are crucial effectors of the innate immune response and important regulators of adaptive immunity. The differentiation and activation of myeloid cells requires the timely regulation of gene expression; this depends on the interplay of a variety of elements, including transcription factors and epigenetic mechanisms. Epigenetic control involves histone modifications and DNA methylation, and is coupled to lineage-specifying transcription factors, upstream signalling pathways and external factors released in the bone marrow, blood and tissue environments. In this Review, we highlight key epigenetic events controlling myeloid cell biology, focusing on those related to myeloid cell differentiation, the acquisition of myeloid identity and innate immune memory.

  17. Novel roles of plant RETINOBLASTOMA-RELATED (RBR) protein in cell proliferation and asymmetric cell division.

    PubMed

    Desvoyes, Bénédicte; de Mendoza, Alex; Ruiz-Trillo, Iñaki; Gutierrez, Crisanto

    2014-06-01

    The retinoblastoma (Rb) protein was identified as a human tumour suppressor protein that controls various stages of cell proliferation through the interaction with members of the E2F family of transcription factors. It was originally thought to be specific to animals but plants contain homologues of Rb, called RETINOBLASTOMA-RELATED (RBR). In fact, the Rb-E2F module seems to be a very early acquisition of eukaryotes. The activity of RBR depends on phosphorylation of certain amino acid residues, which in most cases are well conserved between plant and animal proteins. In addition to its role in cell-cycle progression, RBR has been shown to participate in various cellular processes such as endoreplication, transcriptional regulation, chromatin remodelling, cell growth, stem cell biology, and differentiation. Here, we discuss the most recent advances to define the role of RBR in cell proliferation and asymmetric cell division. These and other reports clearly support the idea that RBR is used as a landing platform of a plethora of cellular proteins and complexes to control various aspects of cell physiology and plant development.

  18. Uric Acid Promotes Osteogenic Differentiation and Inhibits Adipogenic Differentiation of Human Bone Mesenchymal Stem Cells.

    PubMed

    Li, Hui-Zhang; Chen, Zhi; Hou, Cang-Long; Tang, Yi-Xing; Wang, Fei; Fu, Qing-Ge

    2015-08-01

    To investigate the effect of uric acid on the osteogenic and adipogenic differentiation of human bone mesenchymal stem cells (hBMSCs). The hBMSCs were isolated from bone marrow of six healthy donors. Cell morphology was observed by microscopy and cell surface markers (CD44 and CD34) of hBMSCs were analyzed by immunofluorescence. Cell morphology and immunofluorescence analysis showed that hBMSCs were successfully isolated from bone marrow. The number of hBMSCs in uric acid groups was higher than that in the control group on day 3, 4, and 5. Alizarin red staining showed that number of calcium nodules in uric acid groups was more than that of the control group. Oil red-O staining showed that the number of red fat vacuoles decreased with the increased concentration of uric acid. In summary, uric acid could promote the proliferation and osteogenic differentiation of hBMSCs while inhibit adipogenic differentiation of hBMSCs.

  19. Integrating human stem cell expansion and neuronal differentiation in bioreactors

    PubMed Central

    Serra, Margarida; Brito, Catarina; Costa, Eunice M; Sousa, Marcos FQ; Alves, Paula M

    2009-01-01

    Background Human stem cells are cellular resources with outstanding potential for cell therapy. However, for the fulfillment of this application, major challenges remain to be met. Of paramount importance is the development of robust systems for in vitro stem cell expansion and differentiation. In this work, we successfully developed an efficient scalable bioprocess for the fast production of human neurons. Results The expansion of undifferentiated human embryonal carcinoma stem cells (NTera2/cl.D1 cell line) as 3D-aggregates was firstly optimized in spinner vessel. The media exchange operation mode with an inoculum concentration of 4 × 105 cell/mL was the most efficient strategy tested, with a 4.6-fold increase in cell concentration achieved in 5 days. These results were validated in a bioreactor where similar profile and metabolic performance were obtained. Furthermore, characterization of the expanded population by immunofluorescence microscopy and flow cytometry showed that NT2 cells maintained their stem cell characteristics along the bioreactor culture time. Finally, the neuronal differentiation step was integrated in the bioreactor process, by addition of retinoic acid when cells were in the middle of the exponential phase. Neurosphere composition was monitored and neuronal differentiation efficiency evaluated along the culture time. The results show that, for bioreactor cultures, we were able to increase significantly the neuronal differentiation efficiency by 10-fold while reducing drastically, by 30%, the time required for the differentiation process. Conclusion The culture systems developed herein are robust and represent one-step-forward towards the development of integrated bioprocesses, bridging stem cell expansion and differentiation in fully controlled bioreactors. PMID:19772662

  20. Hollow fiber culture accelerates differentiation of Caco-2 cells.

    PubMed

    Deng, Xudong; Zhang, Guoliang; Shen, Chong; Yin, Jian; Meng, Qin

    2013-08-01

    Caco-2 cells usually require 21 days of culture for developing sufficient differentiation in traditional two-dimensional Transwell culture, deviating far away from the quick differentiation of enterocytes in vivo. The recently proposed three-dimensional cultures of Caco-2 cells, though imitating the villi/crypt-like microstructure of intestinal epithelium, showed no effect on accelerating the differentiation of Caco-2 cells. In this study, a novel culture of Caco-2 cells on hollow fiber bioreactor was applied to morphologically mimic the human small intestine lumen for accelerating the expression of intestine functions. The porous hollow fibers of polyethersulfone (PES), a suitable membrane material for Caco-2 cell culture, successfully promoted cells to form confluent monolayer on the inner surface. The differentiated functions of Caco-2 cells, represented by alkaline phosphatase, γ-glutamyltransferase, and P-glycoprotein activity, were greatly higher in a 10-day hollow fiber culture than in a 21-day Transwell culture. Moreover, the Caco-2 cells on PES hollow fibers expressed higher F-actin and zonula occludens-1 protein than those on Transwell culture, indicative of an increased mechanical stress in Caco-2 cells on PES hollow fibers. The accelerated differentiation of Caco-2 cells on PES hollow fibers was unassociated with membrane chemical composition and surface roughness, but could be stimulated by hollow fiber configuration, since PES flat membranes with either rough or smooth surface failed to enhance the differentiation of Caco-2. Therefore, the accelerated expression of Caco-2 cell function on hollow fiber culture might show great values in simulation of the tissue microenvironment in vivo and guide the construction of intestinal tissue engineering apparatus.

  1. Control of beta-cell differentiation by the pancreatic mesenchyme.

    PubMed

    Attali, Myriam; Stetsyuk, Volodymyr; Basmaciogullari, Annie; Aiello, Virginie; Zanta-Boussif, Maria A; Duvillie, Bertrand; Scharfmann, Raphael

    2007-05-01

    The importance of mesenchymal-epithelial interactions for normal development of the pancreas was recognized in the early 1960s, and mesenchymal signals have been shown to control the proliferation of early pancreatic progenitor cells. The mechanisms by which the mesenchyme coordinates cell proliferation and differentiation to produce the normal number of differentiated pancreatic cells are not fully understood. Here, we demonstrate that the mesenchyme positively controls the final number of beta-cells that develop from early pancreatic progenitor cells. In vitro, the number of beta-cells that developed from rat embryonic pancreatic epithelia was larger in cultures with mesenchyme than without mesenchyme. The effect of mesenchyme was not due to an increase in beta-cell proliferation but was due to increased proliferation of early pancreatic duodenal homeobox-1 (PDX1)-positive progenitor cells, as confirmed by bromodeoxyuridine incorporation. Consequently, the window during which early PDX1(+) pancreatic progenitor cells differentiated into endocrine progenitor cells expressing Ngn3 was extended. Fibroblast growth factor 10 mimicked mesenchyme effects on proliferation of early PDX1(+) progenitor cells and induction of Ngn3 expression. Taken together, our results indicate that expansion of early PDX1(+) pancreatic progenitor cells represents a way to increase the final number of beta-cells developing from early embryonic pancreas.

  2. Mutagenesis and differentiation induction in mammalian cells by environmental chemicals

    SciTech Connect

    Friedman, J.; Huberman, E.

    1980-01-01

    These studies indicate that in agreement with the somatic mutation hypothesis, chemical carcinogens: (1) are mutagenic for mammalian cells as tested in the cell-mediated assay; (2) the degree of mutagenicity is correlated with their degree of carcinogenicity; (3) that at least in cases when analyzed carefully the metabolites responsible for mutagenesis are also responsible for initiating the carcinogenic event; and (4) that a cell organ type specificity can be established using the cell-mediated assay. Studies with HL-60 cells and HO melanoma cells and those of others suggest that tumor-promoting phorbol diesters can alter cell differentiation in various cell types and that the degree of the observed alteration in the differentiation properties may be related to the potency of the phorbol esters. Thus these and similar systems may serve as models for both studies and identification of certain types of tumor promoting agents. (ERB)

  3. Differentiation-inducing activity of lupeol, a lupane-type triterpene from Chinese dandelion root (Hokouei-kon), on a mouse melanoma cell line.

    PubMed

    Hata, K; Ishikawa, K; Hori, K; Konishi, T

    2000-08-01

    We examined the differentiation-inducing effects of extracts of 49 wild plants, 25 types of seaweed and 26 mushrooms in Akita on the human leukemia cell line HL60 and a B16 mouse melanoma-derived sub-clone with high differentiation capability (B16 2F2). Differentiation inducers of HL60 cells such as retinoic acid, showed no effects on the differentiation of B16 2F2 cells. Furthermore, chemical compounds known to be inducers of B16 cells, did not induce differentiation of HL60 cells. Screening tests showed that the differentiation of HL60 cells was induced by extracts of 28 wild plants, 10 types of seaweed and 2 mushrooms, and melanogenesis of B16 2F2 cells was increased by extracts of 21 wild plants, 8 types of seaweed and 7 mushrooms. All of the alcoholic extracts of plants belonging to the subfamily Cichorioideae of the family Compositae caused cell differentiation of the melanoma cell line. The extracts of Chinese dandelion root, also inhibited cell growth and induced melanogenesis of B16 2F2 cells. We isolated the active compound from ethanol extracts of the crude drug. Chemical and physical data for the active compound were identical with those for lupeol, a lupane-type triterpene.

  4. Differential MDR in Breast Cancer Stem Cells

    DTIC Science & Technology

    2006-05-01

    dramatic example can be found in chemotherapy-induced alopecia , which results from damage to the rapidly cycling progenitor cells of the hair follicle...Paus and Cotsarelis, 1999, Alonso and Fuchs, 2003). However, alopecia is reversed on cessation of therapy because the common precursor of the four...damage to tissue stem cells. A dramatic example can be found in chemotherapy-induced alopecia , which results from damage to the progenitor cells of the

  5. Hepatic differentiation of embryonic stem cells by murine fetal liver mesenchymal cells.

    PubMed

    Ishii, Takamichi; Yasuchika, Kentaro; Ikai, Iwao

    2013-01-01

    Hepatocytes derived from embryonic stem cells (ESCs) are a potential cell source for regenerative medicine. However, it has been technically difficult to differentiate ESCs into mature hepatocytes because the definitive growth factors and molecular mechanisms governing hepatocyte differentiation have not yet been well defined. The CD45(-)CD49f(+/-)Thy1(+)gp38(+) mesenchymal cells that reside in murine fetal livers induce hepatic progenitor cells to differentiate into mature hepatocytes by direct cell-cell contact. Utilizing these cells, we employ a two-step procedure for hepatic maturation of ESCs: first, ESCs are differentiated into endodermal cells or hepatic progenitor cells, and second, ESC-derived endodermal cells are matured into functional hepatocytes by coculture with murine fetal liver mesenchymal cells. The ESC-derived hepatocyte-like cells possess hepatic functions, including ammonia removal activity, albumin secretion ability, glycogen synthesis and storage, and cytochrome P450 enzymatic activity.

  6. An improved protocol to study the plant cell wall proteome

    PubMed Central

    Printz, Bruno; Dos Santos Morais, Raphaël; Wienkoop, Stefanie; Sergeant, Kjell; Lutts, Stanley; Hausman, Jean-Francois; Renaut, Jenny

    2015-01-01

    Cell wall proteins were extracted from alfalfa stems according to a three-steps extraction procedure using sequentially CaCl2, EGTA, and LiCl-complemented buffers. The efficiency of this protocol for extracting cell wall proteins was compared with the two previously published methods optimized for alfalfa stem cell wall protein analysis. Following LC-MS/MS analysis the three-steps extraction procedure resulted in the identification of the highest number of cell wall proteins (242 NCBInr identifiers) and gave the lowest percentage of non-cell wall proteins (about 30%). However, the three protocols are rather complementary than substitutive since 43% of the identified proteins were specific to one protocol. This three-step protocol was therefore selected for a more detailed proteomic characterization using 2D-gel electrophoresis. With this technique, 75% of the identified proteins were shown to be fraction-specific and 72.7% were predicted as belonging to the cell wall compartment. Although, being less sensitive than LC-MS/MS approaches in detecting and identifying low-abundant proteins, gel-based approaches are valuable tools for the differentiation and relative quantification of protein isoforms and/or modified proteins. In particular isoforms, having variations in their amino-acid sequence and/or carrying different N-linked glycan chains were detected and characterized. This study highlights how the extracting protocols as well as the analytical techniques devoted to the study of the plant cell wall proteome are complementary and how they may be combined to elucidate the dynamism of the plant cell wall proteome in biological studies. Data are available via ProteomeXchange with identifier PXD001927. PMID:25914713

  7. Arabidopsis and Tobacco SUPERMAN regulate hormone signalling and mediate cell proliferation and differentiation

    PubMed Central

    Nibau, Candida; Di Stilio, Verónica S.; Wu, Hen-ming; Cheung, Alice Y.

    2011-01-01

    Arabidopsis thaliana SUPERMAN (SUP) plays an important role during flower development by maintaining the boundary between stamens and carpels in the inner two whorls. It was proposed that SUP maintains this boundary by regulating cell proliferation in both whorls, as loss-of-function superman mutants produce more stamens at the expense of carpels. However, the cellular mechanism that underlies SUP function remains unknown. Here Arabidopsis or tobacco (Nicotiana tabacum) SUP was overexpressed in tobacco plants to substantiate SUP's role as a regulator of cell proliferation and boundary definition and provide evidence that its biological role may be mediated via hormonal changes. It was found that moderate levels of SUP stimulated cell growth and proliferation, whereas high levels were inhibitory. SUP stimulated auxin- and cytokinin-regulated processes, and cells overexpressing SUP displayed reduced hormone dependency for proliferation and regeneration into plants. SUP also induced proliferation of female traits in the second and third flower whorls and promoted differentiation of petaloid properties in sepals, further supporting a role for SUP as a boundary regulator. Moreover, cytokinin suppressed stamen development and promoted differentiation of carpeloid tissues, suggesting that SUP may regulate male and female development via its effect on cytokinin signalling. Taken together, these observations suggest a model whereby the effect of SUP on cell growth and proliferation involves the modulation of auxin- and cytokinin-regulated processes. Furthermore, differential SUP expression or different sensitivities of different cell types to SUP may determine whether SUP stimulates or suppresses their proliferation. PMID:20980362

  8. Propolis Inhibits Neurite Outgrowth in Differentiating SH-SY5Y Human Neuroblastoma Cells

    PubMed Central

    Kim, Han Bit; Yoo, Byung Sun

    2016-01-01

    Propolis is a multicomponent, active, complex resinous substance collected by honeybees from a variety of plant sources. We have studied the effect of propolis on neurite outgrowth of SH-SY5Y human neuroblastoma cells induced to differentiate by all-trans-retinoic acid (RA). Propolis, at a concentration of 3 μg/mL, had no significant effect on the viability of differentiating SH-SY5Y cells. However, the neurite outgrowth of the differentiating SH-SY5Y cells treated with propolis (0.3~3 μg/mL) for 48 hr was significantly inhibited in a dose-dependent manner. Treatment of RA-stimulated differentiating SH-SY5Y cells with 0.3 to 3 μg/mL propolis resulted in decreased level of transglutaminase and 43-kDa growth-associated protein (GAP-43) in a dose-dependent manner. The results indicate that propolis is able to inhibit neurite outgrowth of differentiating SH-SY5Y cells. PMID:27437091

  9. Cell shape controls terminal differentiation of human epidermal keratinocytes.

    PubMed Central

    Watt, F M; Jordan, P W; O'Neill, C H

    1988-01-01

    Cultures of human epidermal keratinocytes provide a useful experimental model with which to study the factors that regulate cell proliferation and terminal differentiation. One situation that is known to trigger premature terminal differentiation is suspension culture, when keratinocytes are deprived of substratum and intercellular contact. We have now investigated whether area of substratum contact, and hence cell shape, can regulate terminal differentiation. Keratinocytes were grown on circular adhesive islands that prevented cell-cell contact. By varying island area we could vary cell shape from fully spread to almost spherical. We found that when substratum contact was restricted, DNA synthesis was inhibited and expression of involucrin, a marker of terminal differentiation, was stimulated. Inhibition of proliferation was not a sufficient stimulus for involucrin synthesis in fully spread cells. When DNA synthesis and involucrin expression were plotted against contact area, classic dose-response curves were obtained. Thus cell shape acts as a signal for the terminal differentiation of keratinocytes in culture. Images PMID:2456572

  10. Regulation of RANKL-induced osteoclastic differentiation by vascular cells.

    PubMed

    Tintut, Yin; Abedin, Moeen; Cho, John; Choe, Andrea; Lim, Jina; Demer, Linda L

    2005-08-01

    Vascular calcification is a regulated process of biomineralization resembling osteogenesis. Many bone-related factors, including resorptive osteoclast-like cells, although in low abundance, have been found in calcified atherosclerotic lesions. The regulatory mechanisms governing them in the vasculature, however, are not clear. Previously, we found that calcifying vascular cells (CVC), a subpopulation of bovine aortic smooth muscle cells (BASMC), undergo osteoblastic differentiation and form mineralized nodules. Since osteoblasts and marrow stromal preosteoblasts regulate osteoclastic differentiation in bone, we hypothesized that vascular cells also regulate differentiation of osteoclastic precursors in the artery wall. Peripheral blood monocytes, which are osteoclast precursors, were co-cultured with CVC or BASMC. Results showed that monocytes co-cultured with both of the vascular cells yielded fewer resorption pits than monocytes cultured alone. Furthermore, monocytes co-cultured with CVC had fewer resorption pits than those co-cultured with BASMC. Conditioned media from the vascular cells also inhibited resorptive activity of monocytes suggesting that the inhibitory effect was mediated in part by soluble factors. Compared with BASMC, CVC had lower mRNA expression for osteopontin, which promotes osteoclast attachment, but greater mRNA expression for the soluble inhibitory cytokine, IL-18. Increased osteoclastic differentiation was observed when neutralizing antibody to IL-18 receptor was added to the cultures of preosteoclasts with CVC conditioned media. Osteoprotegerin, another osteoclast inhibitory cytokine, was expressed at similar levels in both cultures. These results suggest that vascular cells inhibit osteoclastic differentiation, and that CVC have greater inhibitory effects than BASMC.

  11. Genetic and ecotypic differentiation in a Californian plant polyploid complex (Grindelia, Asteraceae).

    PubMed

    Moore, Abigail J; Moore, William L; Baldwin, Bruce G

    2014-01-01

    Studies of ecotypic differentiation in the California Floristic Province have contributed greatly to plant evolutionary biology since the pioneering work of Clausen, Keck, and Hiesey. The extent of gene flow and genetic differentiation across interfertile ecotypes that span major habitats in the California Floristic Province is understudied, however, and is important for understanding the prospects for local adaptation to evolve or persist in the face of potential gene flow across populations in different ecological settings. We used microsatellite data to examine local differentiation in one of these lineages, the Pacific Coast polyploid complex of the plant genus Grindelia (Asteraceae). We examined 439 individuals in 10 different populations. The plants grouped broadly into a coastal and an inland set of populations. The coastal group contained plants from salt marshes and coastal bluffs, as well as a population growing in a serpentine grassland close to the coast, while the inland group contained grassland plants. No evidence for hybridization was found at the single location where adjacent populations of the two groups were sampled. In addition to differentiation along ecotypic lines, there was also a strong signal of local differentiation, with the plants grouping strongly by population. The strength of local differentiation is consistent with the extensive morphological variation observed across populations and the history of taxonomic confusion in the group. The Pacific Clade of Grindelia and other young Californian plant groups warrant additional analysis of evolutionary divergence along the steep coast-to-inland climatic gradient, which has been associated with local adaptation and ecotype formation since the classic studies of Clausen, Keck, and Hiesey.

  12. Genetic and Ecotypic Differentiation in a Californian Plant Polyploid Complex (Grindelia, Asteraceae)

    PubMed Central

    Moore, Abigail J.; Moore, William L.; Baldwin, Bruce G.

    2014-01-01

    Studies of ecotypic differentiation in the California Floristic Province have contributed greatly to plant evolutionary biology since the pioneering work of Clausen, Keck, and Hiesey. The extent of gene flow and genetic differentiation across interfertile ecotypes that span major habitats in the California Floristic Province is understudied, however, and is important for understanding the prospects for local adaptation to evolve or persist in the face of potential gene flow across populations in different ecological settings. We used microsatellite data to examine local differentiation in one of these lineages, the Pacific Coast polyploid complex of the plant genus Grindelia (Asteraceae). We examined 439 individuals in 10 different populations. The plants grouped broadly into a coastal and an inland set of populations. The coastal group contained plants from salt marshes and coastal bluffs, as well as a population growing in a serpentine grassland close to the coast, while the inland group contained grassland plants. No evidence for hybridization was found at the single location where adjacent populations of the two groups were sampled. In addition to differentiation along ecotypic lines, there was also a strong signal of local differentiation, with the plants grouping strongly by population. The strength of local differentiation is consistent with the extensive morphological variation observed across populations and the history of taxonomic confusion in the group. The Pacific Clade of Grindelia and other young Californian plant groups warrant additional analysis of evolutionary divergence along the steep coast-to-inland climatic gradient, which has been associated with local adaptation and ecotype formation since the classic studies of Clausen, Keck, and Hiesey. PMID:24755840

  13. Arsenic inhibits hedgehog signaling during P19 cell differentiation

    SciTech Connect

    Liu, Jui Tung; Bain, Lisa J.

    2014-12-15

    Arsenic is a toxicant found in ground water around the world, and human exposure mainly comes from drinking water or from crops grown in areas containing arsenic in soils or water. Epidemiological studies have shown that arsenic exposure during development decreased intellectual function, reduced birth weight, and altered locomotor activity, while in vitro studies have shown that arsenite decreased muscle and neuronal cell differentiation. The sonic hedgehog (Shh) signaling pathway plays an important role during the differentiation of both neurons and skeletal muscle. The purpose of this study was to investigate whether arsenic can disrupt Shh signaling in P19 mouse embryonic stem cells, leading to changes muscle and neuronal cell differentiation. P19 embryonic stem cells were exposed to 0, 0.25, or 0.5 μM of sodium arsenite for up to 9 days during cell differentiation. We found that arsenite exposure significantly reduced transcript levels of genes in the Shh pathway in both a time and dose-dependent manner. This included the Shh ligand, which was decreased 2- to 3-fold, the Gli2 transcription factor, which was decreased 2- to 3-fold, and its downstream target gene Ascl1, which was decreased 5-fold. GLI2 protein levels and transcriptional activity were also reduced. However, arsenic did not alter GLI2 primary cilium accumulation or nuclear translocation. Moreover, additional extracellular SHH rescued the inhibitory effects of arsenic on cellular differentiation due to an increase in GLI binding activity. Taken together, we conclude that arsenic exposure affected Shh signaling, ultimately decreasing the expression of the Gli2 transcription factor. These results suggest a mechanism by which arsenic disrupts cell differentiation. - Highlights: • Arsenic exposure decreases sonic hedgehog pathway-related gene expression. • Arsenic decreases GLI2 protein levels and transcriptional activity in P19 cells. • Arsenic exposure does not alter the levels of SHH

  14. Histone H1 Depletion Impairs Embryonic Stem Cell Differentiation

    PubMed Central

    Cao, Kaixiang; Krauth, Beth; Ho, Po-Yi; Medrzycki, Magdalena; Berhe, Dawit T.; Pan, Chenyi; McDevitt, Todd C.; Fan, Yuhong

    2012-01-01

    Pluripotent embryonic stem cells (ESCs) are known to possess a relatively open chromatin structure; yet, despite efforts to characterize the chromatin signatures of ESCs, the role of chromatin compaction in stem cell fate and function remains elusive. Linker histone H1 is important for higher-order chromatin folding and is essential for mammalian embryogenesis. To investigate the role of H1 and chromatin compaction in stem cell pluripotency and differentiation, we examine the differentiation of embryonic stem cells that are depleted of multiple H1 subtypes. H1c/H1d/H1e triple null ESCs are more resistant to spontaneous differentiation in adherent monolayer culture upon removal of leukemia inhibitory factor. Similarly, the majority of the triple-H1 null embryoid bodies (EBs) lack morphological structures representing the three germ layers and retain gene expression signatures characteristic of undifferentiated ESCs. Furthermore, upon neural differentiation of EBs, triple-H1 null cell cultures are deficient in neurite outgrowth and lack efficient activation of neural markers. Finally, we discover that triple-H1 null embryos and EBs fail to fully repress the expression of the pluripotency genes in comparison with wild-type controls and that H1 depletion impairs DNA methylation and changes of histone marks at promoter regions necessary for efficiently silencing pluripotency gene Oct4 during stem cell differentiation and embryogenesis. In summary, we demonstrate that H1 plays a critical role in pluripotent stem cell differentiation, and our results suggest that H1 and chromatin compaction may mediate pluripotent stem cell differentiation through epigenetic repression of the pluripotency genes. PMID:22589736

  15. Genes and transposons are differentially methylated in plants, but not in mammals.

    PubMed

    Rabinowicz, Pablo D; Palmer, Lance E; May, Bruce P; Hemann, Michael T; Lowe, Scott W; McCombie, W Richard; Martienssen, Robert A

    2003-12-01

    DNA methylation is found in many eukaryotes, but its function is still controversial. We have studied the methylation of plant and animal genomes using a PCR-based technique amenable for high throughput. Repetitive elements are methylated in both organisms, but whereas most mammalian exons are methylated, plant exons are not. Thus, targeting of methylation specifically to transposons appears to be restricted to plants. We propose that the mechanistic basis of this difference may involve RNA interference. Sequencing strategies that depend on differential methylation are predicted to have different outcomes in plant and mammalian genomes.

  16. Molecular ties between the cell cycle and differentiation in embryonic stem cells.

    PubMed

    Li, Victor C; Kirschner, Marc W

    2014-07-01

    Attainment of the differentiated state during the final stages of somatic cell differentiation is closely tied to cell cycle progression. Much less is known about the role of the cell cycle at very early stages of embryonic development. Here, we show that molecular pathways involving the cell cycle can be engineered to strongly affect embryonic stem cell differentiation at early stages in vitro. Strategies based on perturbing these pathways can shorten the rate and simplify the lineage path of ES differentiation. These results make it likely that pathways involving cell proliferation intersect at various points with pathways that regulate cell lineages in embryos and demonstrate that this knowledge can be used profitably to guide the path and effectiveness of cell differentiation of pluripotent cells.

  17. Efficient differentiation of human embryonic stem cells to definitive endoderm.

    PubMed

    D'Amour, Kevin A; Agulnick, Alan D; Eliazer, Susan; Kelly, Olivia G; Kroon, Evert; Baetge, Emmanuel E

    2005-12-01

    The potential of human embryonic stem (hES) cells to differentiate into cell types of a variety of organs has generated much excitement over the possible use of hES cells in therapeutic applications. Of great interest are organs derived from definitive endoderm, such as the pancreas. We have focused on directing hES cells to the definitive endoderm lineage as this step is a prerequisite for efficient differentiation to mature endoderm derivatives. Differentiation of hES cells in the presence of activin A and low serum produced cultures consisting of up to 80% definitive endoderm cells. This population was further enriched to near homogeneity using the cell-surface receptor CXCR4. The process of definitive endoderm formation in differentiating hES cell cultures includes an apparent epithelial-to-mesenchymal transition and a dynamic gene expression profile that are reminiscent of vertebrate gastrulation. These findings may facilitate the use of hES cells for therapeutic purposes and as in vitro models of development.

  18. Cell-to-cell communication via plasmodesmata in vascular plants

    PubMed Central

    Sevilem, Iris; Miyashima, Shunsuke; Helariutta, Ykä

    2013-01-01

    In plant development, cell-to-cell signaling is mediated by mobile signals, including transcription factors and small RNA molecules. This communication is essential for growth and patterning. Short-range movement of signals occurs in the extracellular space via the apoplastic pathway or directly from cell-to-cell via the symplastic pathway. Symplastic transport is mediated by plant specific structures called plasmodesmata, which are plasma membrane-lined pores that traverse the cell walls of adjacent cells thus connecting their cytoplasms. However, a thorough understanding of molecules moving via plasmodesmata and regulatory networks relying on symplastic signaling is lacking. Traffic via plasmodesmata is highly regulated, and callose turnover is known to be one mechanism. In Arabidopsis, plasmodesmata apertures can be regulated in a spatially and temporally specific manner with the icals3m, an inducible vector system expressing the mutated CalS3 gene encoding a plasmodesmata localized callose synthase that increases callose deposition at plasmodesmata. We discuss strategies to use the icals3m system for global analyses on symplastic signaling in plants. PMID:23076211

  19. Cell-to-cell communication via plasmodesmata in vascular plants.

    PubMed

    Sevilem, Iris; Miyashima, Shunsuke; Helariutta, Ykä

    2013-01-01

    In plant development, cell-to-cell signaling is mediated by mobile signals, including transcription factors and small RNA molecules. This communication is essential for growth and patterning. Short-range movement of signals occurs in the extracellular space via the apoplastic pathway or directly from cell-to-cell via the symplastic pathway. Symplastic transport is mediated by plant specific structures called plasmodesmata, which are plasma membrane-lined pores that traverse the cell walls of adjacent cells thus connecting their cytoplasms. However, a thorough understanding of molecules moving via plasmodesmata and regulatory networks relying on symplastic signaling is lacking. Traffic via plasmodesmata is highly regulated, and callose turnover is known to be one mechanism. In Arabidopsis, plasmodesmata apertures can be regulated in a spatially and temporally specific manner with the icals3m, an inducible vector system expressing the mutated CalS3 gene encoding a plasmodesmata localized callose synthase that increases callose deposition at plasmodesmata. We discuss strategies to use the icals3m system for global analyses on symplastic signaling in plants.

  20. Cartilage stem cells: regulation of differentiation.

    PubMed

    Solursh, M

    1989-01-01

    The developing limb bud is a useful source of cartilage stem cells for studies on the regulation of chondrogenesis. In high density cultures these cells can progress through all stages of chondrogenesis to produce mineralized hypertrophic cartilage. If the cells are maintained in a spherical shape, single stem cells can progress through a similar sequence. The actin cytoskeleton is implicated in the regulation of chondrogenesis since conditions that favor its disruption promote chondrogenesis and conditions that favor actin assembly inhibit chondrogenesis. Since a number of extracellular matrix receptors mediate effects of the extracellular matrix on cytoskeletal organization and some of these receptors are developmentally regulated, it is proposed that matrix receptor expression plays a central role in the divergence of connective tissue cells during development.

  1. The potential of single-cell profiling in plants.

    PubMed

    Efroni, Idan; Birnbaum, Kenneth D

    2016-04-05

    Single-cell transcriptomics has been employed in a growing number of animal studies, but the technique has yet to be widely used in plants. Nonetheless, early studies indicate that single-cell RNA-seq protocols developed for animal cells produce informative datasets in plants. We argue that single-cell transcriptomics has the potential to provide a new perspective on plant problems, such as the nature of the stem cells or initials, the plasticity of plant cells, and the extent of localized cellular responses to environmental inputs. Single-cell experimental outputs require different analytical approaches compared with pooled cell profiles and new tools tailored to single-cell assays are being developed. Here, we highlight promising new single-cell profiling approaches, their limitations as applied to plants, and their potential to address fundamental questions in plant biology.

  2. Analysis of cell differentiation by division tracking cytometry.

    PubMed

    Ko, Kap-Hyoun; Odell, Ross; Nordon, Robert E

    2007-10-01

    We propose a quantitative method to characterize growth and differentiation dynamics of multipotent cells from time series carboxyfluorescein diacetate, succinimidyl ester (CFDA-SE) division tracking data. The dynamics of cell proliferation and differentiation was measured by combining (CFDA-SE) division tracking with phenotypic analysis. We define division tracking population statistics such as precursor cell frequency, generation time and renewal rate that characterize growth of various phenotypes in a heterogeneous culture system. This method is illustrated by study of the divisional recruitment of cord blood CD34(+) cells by hematopoietic growth factors. The technical issue of assigning the correct generation number to cells was addressed by employing high-resolution division tracking methodology and daily histogram analysis. We also quantified division-tracking artifacts such as CFDA-SE degeneration and cellular auto-fluorescence. Mitotic activation of cord blood CD34(+) cells by cytokines commenced after 2 days of cytokine stimulation. Mean generation number increased linearly thereafter, and it was conclusively shown that CD34(+) cells cycle slower than CD34(-) cells. Generation times for CD34(+) and CD34(-) cells were 24.7 +/- 0.8 h and 15.1 +/- 0.9 h (+/-SD, n = 5), respectively. The 20-fold increase in CD34(+) cell numbers at Day 6 could be attributed to a high CD34(+) cell renewal rate (91% +/- 2% per division). Although cultures were initiated with highly purified CD34(+) cells (approximately 96%), CD34(-) numbers had expanded rapidly by Day 6. This rapid expansion could be explained by their short generation time as well as a small fraction of CD34(+) cells (approximately 5%) that differentiated into CD34(-) cells. Multitype division tracking provides a detailed analysis of multipotent cell differentiation dynamics.

  3. Cell Fate and Differentiation of Bone Marrow Mesenchymal Stem Cells

    PubMed Central

    Jimi, Eijiro

    2016-01-01

    Osteoblasts and bone marrow adipocytes originate from bone marrow mesenchymal stem cells (BMMSCs) and there appears to be a reciprocal relationship between adipogenesis and osteoblastogenesis. Alterations in the balance between adipogenesis and osteoblastogenesis in BMMSCs wherein adipogenesis is increased relative to osteoblastogenesis are associated with decreased bone quality and quantity. Several proteins have been reported to regulate this reciprocal relationship but the exact nature of the signals regulating the balance between osteoblast and adipocyte formation within the bone marrow space remains to be determined. In this review, we focus on the role of Transducin-Like Enhancer of Split 3 (TLE3), which was recently reported to regulate the balance between osteoblast and adipocyte formation from BMMSCs. We also discuss evidence implicating canonical Wnt signalling, which plays important roles in both adipogenesis and osteoblastogenesis, in regulating TLE3 expression. Currently, there is demand for new effective therapies that target the stimulation of osteoblast differentiation to enhance bone formation. We speculate that reducing TLE3 expression or activity in BMMSCs could be a useful approach towards increasing osteoblast numbers and reducing adipogenesis in the bone marrow environment. PMID:27298623

  4. Do plant cell walls have a code?

    PubMed

    Tavares, Eveline Q P; Buckeridge, Marcos S

    2015-12-01

    A code is a set of rules that establish correspondence between two worlds, signs (consisting of encrypted information) and meaning (of the decrypted message). A third element, the adaptor, connects both worlds, assigning meaning to a code. We propose that a Glycomic Code exists in plant cell walls where signs are represented by monosaccharides and phenylpropanoids and meaning is cell wall architecture with its highly complex association of polymers. Cell wall biosynthetic mechanisms, structure, architecture and properties are addressed according to Code Biology perspective, focusing on how they oppose to cell wall deconstruction. Cell wall hydrolysis is mainly focused as a mechanism of decryption of the Glycomic Code. Evidence for encoded information in cell wall polymers fine structure is highlighted and the implications of the existence of the Glycomic Code are discussed. Aspects related to fine structure are responsible for polysaccharide packing and polymer-polymer interactions, affecting the final cell wall architecture. The question whether polymers assembly within a wall display similar properties as other biological macromolecules (i.e. proteins, DNA, histones) is addressed, i.e. do they display a code?

  5. Differentiation of highly metastatic nasopharyngeal carcinoma cells using multiphoton microscopy

    NASA Astrophysics Data System (ADS)

    Zhan, Zhenlin; Sun, Zhenzhen; Li, Jingwen; Ye, Qing; Zhuo, Shuangmu; Xie, Shusen

    2016-10-01

    The primary hypothesis tested in the study was that nasopharyngeal carcinoma (NPC) cells at different stage of invasion and metastasis can be differentiated using multiphoton microscopy (MPM). CNE1 and CNE2Z cells were cultured and used in this study. The activity of cell migration and invasion was measured using Transwell assays. At the same time, the morphologic features were quantified from the multiphoton images. The measurements of Transwell migration and invasion showed that the invasion and migration of CNE2Z cells were significantly enhanced when compared with that of CNE1 cells. Also, statistically significant differences in the morphologic features were found between two kinds of cancer cells. In conclusion, it is feasible to use MPM to differentiate cancer cells with different stage of invasion and metastasis.

  6. Heterogeneous differentiation patterns of individual CD8+ T cells.

    PubMed

    Gerlach, Carmen; Rohr, Jan C; Perié, Leïla; van Rooij, Nienke; van Heijst, Jeroen W J; Velds, Arno; Urbanus, Jos; Naik, Shalin H; Jacobs, Heinz; Beltman, Joost B; de Boer, Rob J; Schumacher, Ton N M

    2013-05-03

    Upon infection, antigen-specific CD8(+) T lymphocyte responses display a highly reproducible pattern of expansion and contraction that is thought to reflect a uniform behavior of individual cells. We tracked the progeny of individual mouse CD8(+) T cells by in vivo lineage tracing and demonstrated that, even for T cells bearing identical T cell receptors, both clonal expansion and differentiation patterns are heterogeneous. As a consequence, individual naïve T lymphocytes contributed differentially to short- and long-term protection, as revealed by participation of their progeny during primary versus recall infections. The discordance in fate of individual naïve T cells argues against asymmetric division as a singular driver of CD8(+) T cell heterogeneity and demonstrates that reproducibility of CD8(+) T cell responses is achieved through population averaging.

  7. Myeloid cell origins, differentiation, and clinical implications

    PubMed Central

    Weiskopf, Kipp; Schnorr, Peter J.; Pang, Wendy W.; Chao, Mark P.; Chhabra, Akanksha; Seita, Jun; Feng, Mingye; Weissman, Irving L.

    2016-01-01

    The hematopoietic stem cell (HSC) is a multipotent stem cell that resides in the bone marrow and has the ability to form all of the cells of the blood and immune system. Since its first purification in 1988, additional studies have refined the phenotype and functionality of HSCs and characterized all of their downstream progeny. The hematopoietic lineage is divided into two main branches: the myeloid and lymphoid arms. The myeloid arm is characterized by the Common Myeloid Progenitor and all of its resulting cell types. The stages of hematopoiesis have been defined in both mice and humans. During embryological development, the earliest hematopoiesis takes place in yolk sac blood islands then migrates to the fetal liver and hematopoietic organs. Some adult myeloid populations develop directly from yolk sac progenitors without apparent bone marrow intermediates, such as tissue resident macrophages. Hematopoiesis also changes over time, with a bias of the dominating HSCs towards myeloid development as animals age. Defects in myelopoiesis contribute to many hematologic disorders, and some of these can be overcome with therapies that target the aberrant stage of development. Furthermore, insights into myeloid development have informed us of mechanisms of programmed cell removal. The CD47/SIRPα axis, a myeloid-specific immune checkpoint, limits macrophage removal of HSCs but can be exploited by hematologic and solid malignancies. Therapeutics targeting CD47 represent a new strategy for treating cancer. Overall, an understanding of hematopoiesis and myeloid cell development has implications for regenerative medicine, hematopoietic cell transplantation, malignancy, and many other diseases. PMID:27763252

  8. Human embryonic stem cells differentiate into functional renal proximal tubular-like cells.

    PubMed

    Narayanan, Karthikeyan; Schumacher, Karl M; Tasnim, Farah; Kandasamy, Karthikeyan; Schumacher, Annegret; Ni, Ming; Gao, Shujun; Gopalan, Began; Zink, Daniele; Ying, Jackie Y

    2013-04-01

    Renal cells are used in basic research, disease models, tissue engineering, drug screening, and in vitro toxicology. In order to provide a reliable source of human renal cells, we developed a protocol for the differentiation of human embryonic stem cells into renal epithelial cells. The differentiated stem cells expressed markers characteristic of renal proximal tubular cells and their precursors, whereas markers of other renal cell types were not expressed or expressed at low levels. Marker expression patterns of these differentiated stem cells and in vitro cultivated primary human renal proximal tubular cells were comparable. The differentiated stem cells showed morphological and functional characteristics of renal proximal tubular cells, and generated tubular structures in vitro and in vivo. In addition, the differentiated stem cells contributed in organ cultures for the formation of simple epithelia in the kidney cortex. Bioreactor experiments showed that these cells retained their functional characteristics under conditions as applied in bioartificial kidneys. Thus, our results show that human embryonic stem cells can differentiate into renal proximal tubular-like cells. Our approach would provide a source for human renal proximal tubular cells that are not affected by problems associated with immortalized cell lines or primary cells.

  9. Chondrogenic differentiation of human embryonic germ cell derived cells in hydrogels.

    PubMed

    Varghese, Shyni; Theprungsirikul, Paranduangji; Ferran, Angela; Hwang, Nathaniel; Canver, Adam; Elisseeff, Jennifer

    2006-01-01

    Human embryonic germ (hEG) cells have the potential to self-renew over long periods of time and differentiate into various lineages. Cells derived from embryoid bodies of hEG cells express a broad spectrum of gene markers and have been induced towards cells of ecto-dermal and recently endo-dermal and mesenchymal lineages. LVEC cells express a number of surface marker proteins characteristic of mesenchymal stem cells (MSCs), indicating the potential of these cells to differentiate into mesenchymal tissues. Here we demonstrate the homogenous differentiation of LVEC cells into hyaline cartilage. Three dimensional tissue formation is achieved by encapsulating cells in synthetic hydrogels followed by incubation in chondrocyte-conditioned culture medium. Homogenous hyaline cartilage was produced, even after 63 population doublings (13 passages). The high proliferative capacity of these cells without teratoma formation, homogenous differentiation, and three-dimensional cartilage tissue formation suggests the significant potential of LVEC cells for cartilage tissue engineering applications.

  10. [Feedback control mechanisms of plant cell expansion

    SciTech Connect

    Cosgrove, D.J.

    1992-01-01

    We have generated considerable evidence for the significance of wall stress relaxation in the control of plant growth and found that several agents (gibberellin, light, genetic loci for dwarf stature) influence growth rate via alteration of wall relaxation. We have refined our methods for measuring wall relaxation and, moreover, have found that wall relaxation properties bear only a distance relationship to wall mechanical properties. We have garnered novel insights into the nature of cell expansion mechanisms by analyzing spontaneous fluctuations of plant growth rate in seedlings. These experiments involved the application of mathematical techniques for analyzing growth rate fluctuations and the development of new instrumentation for measuring and forcing plant growth in a controlled fashion. These studies conclude that growth rate fluctuations generated by the plant as consequence of a feedback control system. This conclusion has important implications for the nature of wall loosening processes and demands a different framework for thinking about growth control. It also implies the existence of a growth rate sensor.

  11. Neural cells play an inhibitory role in pancreatic differentiation of pluripotent stem cells.

    PubMed

    Nakashima, Ryutaro; Morooka, Mayu; Shiraki, Nobuaki; Sakano, Daisuke; Ogaki, Soichiro; Kume, Kazuhiko; Kume, Shoen

    2015-12-01

    Pancreatic endocrine β-cells derived from embryonic stem (ES) cells and induced pluripotent stem (iPS) cells have received attention as screening systems for therapeutic drugs and as the basis for cell-based therapies. Here, we used a 12-day β-cell differentiation protocol for mouse ES cells and obtained several hit compounds that promoted β-cell differentiation. One of these compounds, mycophenolic acid (MPA), effectively promoted ES cell differentiation with a concomitant reduction of neuronal cells. The existence of neural cell-derived inhibitory humoral factors for β-cell differentiation was suggested using a co-culture system. Based on gene array analysis, we focused on the Wnt/β-catenin pathway and showed that the Wnt pathway inhibitor reversed MPA-induced β-cell differentiation. Wnt pathway activation promoted β-cell differentiation also in human iPS cells. Our results showed that Wnt signaling activation positively regulates β-cell differentiation, and represent a downstream target of the neural inhibitory factor.

  12. Glycomics of Proteoglycan Biosynthesis in Murine Embryonic Stem Cell Differentiation

    PubMed Central

    Nairn, Alison V.; Kinoshita-Toyoda, Akiko; Toyoda, Hidenao; Xie, Jin; Harris, Kyle; Dalton, Stephen; Kulik, Michael; Pierce, J. Michael; Toida, Toshihiko; Moremen, Kelley W.; Linhardt, Robert J.

    2014-01-01

    Glycosaminoglycans (GAGs) play a critical role in binding and activation of growth factors involved in cell signaling critical for developmental biology. The biosynthetic pathways for GAGs have been elucidated over the past decade and now analytical methodology makes it possible to determine GAG composition in as few as 10 million cells. A glycomics approach was used to examine GAG content, composition, and the level of transcripts encoding for GAG biosynthetic enzymes as murine embryonic stem cells (mESCs) differentiate to embryoid bodies (EBs) and to extraembryonic endodermal cells (ExE) to better understand the role of GAGs in stem cell differentiation. Hyaluronan synthesis was enhanced by 13- and 24-fold, most likely due to increased expression of hyaluronan synthase-2. Chondroitin sulfate (CS)/dermatan sulfate (DS) synthesis was enhanced by 4- and 6-fold, and heparan sulfate (HS) synthesis was enhanced by 5- and 8-fold following the transition from mESC to EB and ExE. Transcripts associated with the synthesis of the early precursors were largely unaltered, suggesting other factors account for enhanced GAG synthesis. The composition of both CS/DS and HS also changed upon differentiation. Interestingly, CS type E and highly sulfated HS both increase as mESCs differentiate to EBs and ExE. Differentiation was also accompanied by enhanced 2-sulfation in both CS/DS and HS families. Transcript levels for core proteins generally showed increases or remained constant upon mESC differentiation. Finally, transcripts encoding selected enzymes and isoforms, including GlcNAc-4,6-O-sulfotransferase, C5-epimerases, and 3-O-sulfotransferases involved in late GAG biosynthesis, were also enriched. These biosynthetic enzymes are particularly important in introducing GAG fine structure, essential for intercellular communication, cell adhesion, and outside-in signaling. Knowing the changes in GAG fine structure should improve our understanding the biological properties of

  13. Stonewalling Drosophila stem cell differentiation by epigenetic controls.

    PubMed

    Maines, Jean Z; Park, Joseph K; Williams, Meredith; McKearin, Dennis M

    2007-04-01

    During Drosophila oogenesis, germline stem cell (GSC) identity is maintained largely by preventing the expression of factors that promote differentiation. This is accomplished via the activity of several genes acting either in the GSC or in its niche. The translational repressors Nanos and Pumilio act in GSCs to prevent differentiation, probably by inhibiting the translation of early differentiation factors, whereas niche signals prevent differentiation by silencing transcription of the differentiation factor Bam. We have found that the DNA-associated protein Stonewall (Stwl) is also required for GSC maintenance. stwl is required cell-autonomously; clones of stwl(-) germ cells were lost by differentiation, and ectopic Stwl caused an expansion of GSCs. stwl mutants acted as Suppressors of variegation, indicating that stwl normally acts in chromatin-dependent gene repression. In contrast to several previously described GSC maintenance factors, Stwl probably functions epigenetically to prevent GSC differentiation. Stwl-dependent transcriptional repression does not target bam, but rather Stwl represses the expression of many genes, including those that may be targeted by Nanos and Pumilio translational inhibition.

  14. The role of purinergic receptors in stem cell differentiation

    PubMed Central

    Kaebisch, Constanze; Schipper, Dorothee; Babczyk, Patrick; Tobiasch, Edda

    2014-01-01

    A major challenge modern society has to face is the increasing need for tissue regeneration due to degenerative diseases or tumors, but also accidents or warlike conflicts. There is great hope that stem cell-based therapies might improve current treatments of cardiovascular diseases, osteochondral defects or nerve injury due to the unique properties of stem cells such as their self-renewal and differentiation potential. Since embryonic stem cells raise severe ethical concerns and are prone to teratoma formation, adult stem cells are still in the focus of research. Emphasis is placed on cellular signaling within these cells and in between them for a better understanding of the complex processes regulating stem cell fate. One of the oldest signaling systems is based on nucleotides as ligands for purinergic receptors playing an important role in a huge variety of cellular processes such as proliferation, migration and differentiation. Besides their natural ligands, several artificial agonists and antagonists have been identified for P1 and P2 receptors and are already used as drugs. This review outlines purinergic receptor expression and signaling in stem cells metabolism. We will briefly describe current findings in embryonic and induced pluripotent stem cells as well as in cancer-, hematopoietic-, and neural crest-derived stem cells. The major focus will be placed on recent findings of purinergic signaling in mesenchymal stem cells addressed in in vitro and in vivo studies, since stem cell fate might be manipulated by this system guiding differentiation towards the desired lineage in the future. PMID:26900431

  15. Silicon Micropore based Electromechanical Transducer to Differentiate Tumor Cells

    NASA Astrophysics Data System (ADS)

    Ali, Waqas; Raza, Muhammad U.; Khanzada, Raja R.; Kim, Young-Tae; Iqbal, Samir M.

    2015-03-01

    Solid-state micropores have been used before to differentiate cancer cells from normal cells using size-based filtering. Tumor cells differ from normal ones not only in size but also in physical properties like elasticity, shape, motility etc. Tumor cells show different physical attributes depending on the stage and type of cancer. We report a micropore based electromechanical transducer that differentiated cancer cells based on their mechanophysical properties. The device was interfaced with a high-speed patch-clamp measurement system that biased the ionic solution across the silicon-based membrane. The bias resulted in the flow of ionic current. Electrical pulses were generated when cells passed through. Different cells depicted characteristic pulses. Translocation profiles of cells that were either small or were more elastic and flexible caused electrical pulses shorter in widths and amplitudes whereas cells with larger size or lesser elasticity/flexibility showed deeper and wider pulses. Three non-small cell lung cancer (NSCLC) cell lines NCI-H1155, A549 and NCI-H460 were successfully differentiated. NCI-H1155, due to their comparatively smaller size, were found quickest in translocating through. The solid-sate micropore based electromechanical transducer could process the whole blood sample of cancer patient without any pre-processing requirements and is ideal for point-of-care applications. Support Acknowledged from NSF through ECCS-1201878.

  16. Cell line models for differentiation: preadipocytes and adipocytes.

    PubMed

    Poulos, Sylvia P; Dodson, Michael V; Hausman, Gary J

    2010-10-01

    In vitro models have been invaluable in determining the mechanisms involved in adipocyte proliferation, differentiation, adipokine secretion and gene/protein expression. The cells presently available for research purposes all have unique advantages and disadvantages that one should be aware of when selecting cells. Established cell lines, such as 3T3-L1 cells, are easier and less costly to use than freshly isolated cells, even though freshly isolated cells allow for various comparisons such as the in vitro evaluation of different in vivo conditions that may not be possible using cell lines. Moreover, stem cells, transdifferentiated cells or dedifferentiated cells are relatively new cell models being evaluated for the study of adipocyte regulation and physiology. The focus of this brief review is to highlight similarities and differences in adipocyte models to aid in appropriate model selection and data interpretation for successful advancement of our understanding of adipocyte biology.

  17. Differential Expression of CXCL12 and CXCR4 During Human Fetal Neural Progenitor Cell Differentiation

    PubMed Central

    Peng, Hui; Kolb, Ryan; Kennedy, J. E.

    2007-01-01

    Stromal cell-derived factor 1 alpha (SDF-1α, CXCL12) and its receptor CXCR4 play an important role in the central nervous system (CNS) development and adulthood by mediating cell migration, enhancing precursor cell proliferation, assisting in neuronal circuit formation, and possibly regulating migration during repair. The expression pattern of CXCR4 and CXCL12 during neurogenesis has not been thoroughly elucidated. In this study, we investigated the expression of CXCL12 and CXCR4 during neural progenitor cells (NPC) differentiation by microarray analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) using human fetal NPC as a model system. The production of CXCL12 was measured by enzyme-linked immunosorbent assay (ELISA). CXCR4 expression was determined by florescence-activated cell sorting (FACS) analysis, immunocytochemical staining, and CXCR4-mediated inhibition of cyclic AMP (cAMP) accumulation. Our data demonstrated that CXCR4 expression is significantly upregulated when NPC are differentiated into neuronal precursors, whereas CXCL12 is upregulated when differentiated into astrocytes. We also provide evidence that CXCR4 localization changes as neurons mature. In neuronal precursors, CXCR4 is localized in both neuronal processes and the cell body, whereas in mature neurons, it is primarily expressed on axons and dendrites. This differential expression of CXCR4 and CXCL12 may be important for the temporal regulation of neuronal migration and circuit formation during development and possibly in adult neurogenesis and repair. PMID:18040858

  18. 2003 Plant Cell Walls Gordon Conference

    SciTech Connect

    Daniel J. Cosgrove

    2004-09-21

    This conference will address recent progress in many aspects of cell wall biology. Molecular, genetic, and genomic approaches are yielding major advances in our understanding of the composition, synthesis, and architecture of plant cell walls and their dynamics during growth, and are identifying the genes that encode the machinery needed to make their biogenesis possible. This meeting will bring together international scientists from academia, industry and government labs to share the latest breakthroughs and perspectives on polysaccharide biosynthesis, wood formation, wall modification, expansion and interaction with other organisms, and genomic & evolutionary analyses of wall-related genes, as well as to discuss recent ''nanotechnological'' advances that take wall analysis to the level of a single cell.

  19. Manifold gasket accommodating differential movement of fuel cell stack

    DOEpatents

    Kelley, Dana A.; Farooque, Mohammad

    2007-11-13

    A gasket for use in a fuel cell system having at least one externally manifolded fuel cell stack, for sealing the manifold edge and the stack face. In accordance with the present invention, the gasket accommodates differential movement between the stack and manifold by promoting slippage at interfaces between the gasket and the dielectric and between the gasket and the stack face.

  20. Differentiation stage of myeloma plasma cells: biological and clinical significance.

    PubMed

    Paiva, B; Puig, N; Cedena, M T; de Jong, B G; Ruiz, Y; Rapado, I; Martinez-Lopez, J; Cordon, L; Alignani, D; Delgado, J A; van Zelm, M C; Van Dongen, J J M; Pascual, M; Agirre, X; Prosper, F; Martín-Subero, J I; Vidriales, M-B; Gutierrez, N C; Hernandez, M T; Oriol, A; Echeveste, M A; Gonzalez, Y; Johnson, S K; Epstein, J; Barlogie, B; Morgan, G J; Orfao, A; Blade, J; Mateos, M V; Lahuerta, J J; San-Miguel, J F

    2017-02-01

    The notion that plasma cells (PCs) are terminally differentiated has prevented intensive research in multiple myeloma (MM) about their phenotypic plasticity and differentiation. Here, we demonstrated in healthy individuals (n=20) that the CD19-CD81 expression axis identifies three bone marrow (BM)PC subsets with distinct age-prevalence, proliferation, replication-history, immunoglobulin-production, and phenotype, consistent with progressively increased differentiation from CD19+CD81+ into CD19-CD81+ and CD19-CD81- BMPCs. Afterwards, we demonstrated in 225 newly diagnosed MM patients that, comparing to normal BMPC counterparts, 59% had fully differentiated (CD19-CD81-) clones, 38% intermediate-differentiated (CD19-CD81+) and 3% less-differentiated (CD19+CD81+) clones. The latter patients had dismal outcome, and PC differentiation emerged as an independent prognostic marker for progression-free (HR: 1.7; P=0.005) and overall survival (HR: 2.1; P=0.006). Longitudinal comparison of diagnostic vs minimal-residual-disease samples (n=40) unraveled that in 20% of patients, less-differentiated PCs subclones become enriched after therapy-induced pressure. We also revealed that CD81 expression is epigenetically regulated, that less-differentiated clonal PCs retain high expression of genes related to preceding B-cell stages (for example: PAX5), and show distinct mutation profile vs fully differentiated PC clones within individual patients. Together, we shed new light into PC plasticity and demonstrated that MM patients harbouring less-differentiated PCs have dismal survival, which might be related to higher chemoresistant potential plus different molecular and genomic profiles.

  1. Substrate Induced Osteoblast-Like Differentiation of Stromal Stem Cells

    NASA Astrophysics Data System (ADS)

    Belizar, Jacqueline; Glaser, Reena; Hung, Matthew; Simon, Marcia; Jurukovski, Vladimir; Rafailovich, Miriam; Shih, Alice

    2009-03-01

    We have demonstrated that Adipose-derived stem cells (ASCs) can be induced to biomineralize on a polybutadiene (PB) coated Si substrate. The cells began to generate calcium phosphate deposits after a five-day incubation period in the absence of dexamethasone. Control cells plated on tissue culture PS culture dish (TCP) did not biomineralize. In addition, the biomineralizing culture retained proliferative cells In order to determine whether the induction was transient, we transferred the cells exposed to polybutadiene after 14 and 28-day incubation periods to TCP dishes. These cells continued to biominerlize. Genetic testing is underway which will determine whether differentiation is maintained after transfer.

  2. A plant cell division algorithm based on cell biomechanics and ellipse-fitting

    PubMed Central

    Abera, Metadel K.; Verboven, Pieter; Defraeye, Thijs; Fanta, Solomon Workneh; Hertog, Maarten L. A. T. M.; Carmeliet, Jan; Nicolai, Bart M.

    2014-01-01

    Background and Aims The importance of cell division models in cellular pattern studies has been acknowledged since the 19th century. Most of the available models developed to date are limited to symmetric cell division with isotropic growth. Often, the actual growth of the cell wall is either not considered or is updated intermittently on a separate time scale to the mechanics. This study presents a generic algorithm that accounts for both symmetrically and asymmetrically dividing cells with isotropic and anisotropic growth. Actual growth of the cell wall is simulated simultaneously with the mechanics. Methods The cell is considered as a closed, thin-walled structure, maintained in tension by turgor pressure. The cell walls are represented as linear elastic elements that obey Hooke's law. Cell expansion is induced by turgor pressure acting on the yielding cell-wall material. A system of differential equations for the positions and velocities of the cell vertices as well as for the actual growth of the cell wall is established. Readiness to divide is determined based on cell size. An ellipse-fitting algorithm is used to determine the position and orientation of the dividing wall. The cell vertices, walls and cell connectivity are then updated and cell expansion resumes. Comparisons are made with experimental data from the literature. Key Results The generic plant cell division algorithm has been implemented successfully. It can handle both symmetrically and asymmetrically dividing cells coupled with isotropic and anisotropic growth modes. Development of the algorithm highlighted the importance of ellipse-fitting to produce randomness (biological variability) even in symmetrically dividing cells. Unlike previous models, a differential equation is formulated for the resting length of the cell wall to simulate actual biological growth and is solved simultaneously with the position and velocity of the vertices. Conclusions The algorithm presented can produce different

  3. Multipotent Adult Progenitor Cells from Bone Marrow Differentiate into Chondrocyte-Like Cells.

    PubMed

    Yu, Lele; Weng, Yimin; Shui, Xiaolong; Fang, Wenlai; Zhang, Erge; Pan, Jun

    2015-07-01

    Cartilage tissue engineering has great potential for treating chondral and osteochondral injuries. Efficient seed cells are the key to cartilage tissue engineering. Multipotent adult progenitor cells (MAPCs) have greater differentiation ability than other bone-marrow stem cells, and thus may be candidate seed cells. We attempted to differentiate MAPCs into chondrocyte-like cells to evaluate their suitability as seed cells for cartilage tissue engineering. Toluidine blue and Alcian blue staining suggested that glycosaminoglycan was expressed in differentiated cells. Immunofluorostaining indicated that differentiated human MAPCs (hMAPCs) expressed collagen II. Based on these results, we concluded that bone-marrow-derived hMAPCs could differentiate into chondrocyte-like cells in vitro.

  4. Stimulation of Chondrogenic Differentiation of Mesenchymal Stem Cells

    PubMed Central

    Yu, Da-Ae; Han, Jin; Kim, Byung-Soo

    2012-01-01

    The methods for cartilage repair have been studied so far, yet many of them seem to have limitations due to the low regenerative capacity of articular cartilage. Mesenchymal stem cell (MSC) has been suggested as an alternative solution to remedy this challenging problem. MSCs, which have extensive differentiation capacity, can be induced to differentiate into chondrocytes under specific conditions. Particularly, this review focused on the effects of growth factors, cell-to-cell interactions and biomaterials in chondrogenesis of MSCs. Appropriate stimulations through these factors are crucial in differentiation and proliferation of MSCs. However, use of MSCs for cartilage repair has some drawbacks and risks, such as expression of hypertrophy-related genes in MSCs-derived chondrocytes and consequent calcification or cell death. Nevertheless, the clinical application of MSCs is expected in the future with advanced technology. PMID:24298351

  5. Calcium protects differentiating neuroblastoma cells during 50 Hz electromagnetic radiation.

    PubMed

    Tonini, R; Baroni, M D; Masala, E; Micheletti, M; Ferroni, A; Mazzanti, M

    2001-11-01

    Despite growing concern about electromagnetic radiation, the interaction between 50- to 60-Hz fields and biological structures remains obscure. Epidemiological studies have failed to prove a significantly correlation between exposure to radiation fields and particular pathologies. We demonstrate that a 50- to 60-Hz magnetic field interacts with cell differentiation through two opposing mechanisms: it antagonizes the shift in cell membrane surface charges that occur during the early phases of differentiation and it modulates hyperpolarizing K channels by increasing intracellular Ca. The simultaneous onset of both mechanisms prevents alterations in cell differentiation. We propose that cells are normally protected against electromagnetic insult. Pathologies may arise, however, if intracellular Ca regulation or K channel activation malfunctions.

  6. Isolation and differentiation of Xenopus animal cap cells.

    PubMed

    Ariizumi, Takashi; Takahashi, Shuji; Chan, Te-chuan; Ito, Yuzuru; Michiue, Tatsuo; Asashima, Makoto

    2009-04-01

    Xenopus is used as a model animal for investigating the inductive events and organogenesis that occur during early vertebrate development. Given that they are easy to obtain in high numbers and are relatively large in size, Xenopus embryos are excellent specimens for performing manipulations such as microinjection and microsurgery. The animal cap, which is the area around the animal pole of the blastula, is destined to form the ectoderm during normal development. However, these cells retain pluripotentiality and upon exposure to specific inducers, the animal cap can differentiate into neural, mesodermal, and endodermal tissues. In this sense, the cells of the animal cap are equivalent to mammalian embryonic stem cells. In this unit, the isolation and differentiation of animal cap cells, the so-called animal cap assay, is described. Useful methods for analyzing the mechanism of animal cap differentiation at the molecular level are also described.

  7. Genetic and epigenetic networks controlling T helper 1 cell differentiation.

    PubMed

    Placek, Katarzyna; Coffre, Maryaline; Maiella, Sylvie; Bianchi, Elisabetta; Rogge, Lars

    2009-06-01

    Significant progress has been made during the past years in our understanding of the mechanisms that control the differentiation of naïve CD4(+) T cells into effector T-cell subsets with distinct functional properties. Previous work allowed the identification of key molecules involved in regulating this highly complex process, such as cytokines and their receptors, signal transducers and transcription factors. More recently, the emphasis of research in this field has been to elucidate how the multiplicity of signals is integrated to shape a T helper subset-specific gene-expression program controlling differentiation and effector functions. In this review we will highlight advances that have been made in unravelling the genetic and epigenetic networks controlling differentiation of naïve CD4(+) T cells into interferon-gamma(IFN-gamma)-secreting T helper type 1 (Th1) cells.

  8. Genetic and epigenetic networks controlling T helper 1 cell differentiation

    PubMed Central

    Placek, Katarzyna; Coffre, Maryaline; Maiella, Sylvie; Bianchi, Elisabetta; Rogge, Lars

    2009-01-01

    Significant progress has been made during the past years in our understanding of the mechanisms that control the differentiation of naïve CD4+ T cells into effector T-cell subsets with distinct functional properties. Previous work allowed the identification of key molecules involved in regulating this highly complex process, such as cytokines and their receptors, signal transducers and transcription factors. More recently, the emphasis of research in this field has been to elucidate how the multiplicity of signals is integrated to shape a T helper subset-specific gene-expression program controlling differentiation and effector functions. In this review we will highlight advances that have been made in unravelling the genetic and epigenetic networks controlling differentiation of naïve CD4+ T cells into interferon-γ(IFN-γ)-secreting T helper type 1 (Th1) cells. PMID:19476511

  9. Pax6 is essential for lens fiber cell differentiation.

    PubMed

    Shaham, Ohad; Smith, April N; Robinson, Michael L; Taketo, Makoto M; Lang, Richard A; Ashery-Padan, Ruth

    2009-08-01

    The developing ocular lens provides an excellent model system with which to study the intrinsic and extrinsic cues governing cell differentiation. Although the transcription factors Pax6 and Sox2 have been shown to be essential for lens induction, their later roles during lens fiber differentiation remain largely unknown. Using Cre/loxP mutagenesis, we somatically inactivated Pax6 and Sox2 in the developing mouse lens during differentiation of the secondary lens fibers and explored the regulatory interactions of these two intrinsic factors with the canonical Wnt pathway. Analysis of the Pax6-deficient lenses revealed a requirement for Pax6 in cell cycle exit and differentiation into lens fiber cells. In addition, Pax6 disruption led to apoptosis of lens epithelial cells. We show that Pax6 regulates the Wnt antagonist Sfrp2 in the lens, and that Sox2 expression is upregulated in the Pax6-deficient lenses. However, our study demonstrates that the failure of differentiation following loss of Pax6 is independent of beta-catenin signaling or Sox2 activity. This study reveals that Pax6 is pivotal for initiation of the lens fiber differentiation program in the mammalian eye.

  10. Detection of Osteogenic Differentiation by Differential Mineralized Matrix Production in Mesenchymal Stromal Cells by Raman Spectroscopy

    PubMed Central

    Chen, He-Guei; Chiang, Hui-Hua Kenny; Lee, Oscar Kuang-Sheng

    2013-01-01

    Mesenchymal stromal cells (MSCs) hold great potential in skeletal tissue engineering and regenerative medicine. However, conventional methods that are used in molecular biology to evaluate osteogenic differentiation of MSCs require a relatively large amount of cells. Cell lysis and cell fixation are also required and all these steps are time-consuming. Therefore, it is imperative to develop a facile technique which can provide real-time information with high sensitivity and selectivity to detect the osteogenic maturation of MSCs. In this study, we use Raman spectroscopy as a biosensor to monitor the production of mineralized matrices during osteogenic induction of MSCs. In summary, Raman spectroscopy is an excellent biosensor to detect the extent of maturation level during MSCs-osteoblast differentiation with a non-disruptive, real-time and label free manner. We expect that this study will promote further investigation of stem cell research and clinical applications. PMID:23734254

  11. Evaluation of a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) assay (Keystone Sym)

    EPA Science Inventory

    Our goal is to establish an in vitro model system to evaluate chemical effects using a single stem cell culture technique that would improve throughput and provide quantitative markers of differentiation and cell number. To this end, we have used an adherent cell differentiation ...

  12. Cloning mice and ES cells by nuclear transfer from somatic stem cells and fully differentiated cells.

    PubMed

    Wang, Zhongde

    2011-01-01

    Cloning animals by nuclear transfer (NT) has been successful in several mammalian species. In addition to cloning live animals (reproductive cloning), this technique has also been used in several species to establish cloned embryonic stem (ntES) cell lines from somatic cells. It is the latter application of this technique that has been heralded as being the potential means to produce isogenic embryonic stem cells from patients for cell therapy (therapeutic cloning). These two types of cloning differ only in the steps after cloned embryos are produced: for reproductive cloning the cloned embryos are transferred to surrogate mothers to allow them to develop to full term and for therapeutic cloning the cloned embryos are used to derive ntES cells. In this chapter, a detailed NT protocol in mouse by using somatic stem cells (neuron and skin stem cells) and fully differentiated somatic cells (cumulus cells and fibroblast cells) as nuclear donors is described.

  13. Osteogenic Differentiation of Periosteal Cells During Fracture Healing.

    PubMed

    Wang, Tao; Zhang, Xinping; Bikle, Daniel D

    2017-05-01

    Five to ten percent of fractures fail to heal normally leading to additional surgery, morbidity, and altered quality of life. Fracture healing involves the coordinated action of stem cells primarily coming from the periosteum which differentiate into the chondrocytes and osteoblasts, forming first the soft (cartilage) callus followed by the hard (bone) callus. These stem cells are accompanied by a vascular invasion that appears critical for the differentiation process and which may enable the entry of osteoclasts necessary for the remodeling of the callus into mature bone. However, more research is needed to clarify the signaling events that activate the osteochondroprogenitor cells of periosteum and stimulate their differentiation into chondrocytes and osteoblasts. Ultimately a thorough understanding of the mechanisms for differential regulation of these osteochondroprogenitors will aid in the treatment of bone healing and the prevention of delayed union and nonunion of fractures. In this review, evidence supporting the concept that the periosteal cells are the major cell sources of skeletal progenitors for the fracture callus will be discussed. The osteogenic differentiation of periosteal cells manipulated by Wnt/β-catenin, TGF/BMP, Ihh/PTHrP, and IGF-1/PI3K-Akt signaling in fracture repair will be examined. The effect of physical (hypoxia and hyperoxia) and chemical factors (reactive oxygen species) as well as the potential coordinated regulatory mechanisms in the periosteal progenitor cells promoting osteogenic differentiation will also be discussed. Understanding the regulation of periosteal osteochondroprogenitors during fracture healing could provide insight into possible therapeutic targets and thereby help to enhance future fracture healing and bone tissue engineering approaches. J. Cell. Physiol. 232: 913-921, 2017. © 2016 Wiley Periodicals, Inc.

  14. Differential migration and proliferation of geometrical ensembles of cell clusters

    SciTech Connect

    Kumar, Girish; Chen, Bo; Co, Carlos C.; Ho, Chia-Chi

    2011-06-10

    Differential cell migration and growth drives the organization of specific tissue forms and plays a critical role in embryonic development, tissue morphogenesis, and tumor invasion. Localized gradients of soluble factors and extracellular matrix have been shown to modulate cell migration and proliferation. Here we show that in addition to these factors, initial tissue geometry can feedback to generate differential proliferation, cell polarity, and migration patterns. We apply layer by layer polyelectrolyte assembly to confine multicellular organization and subsequently release cells to demonstrate the spatial patterns of cell migration and growth. The cell shapes, spreading areas, and cell-cell contacts are influenced strongly by the confining geometry. Cells within geometric ensembles are morphologically polarized. Symmetry breaking was observed for cells on the circular pattern and cells migrate toward the corners and in the direction parallel to the longest dimension of the geometric shapes. This migration pattern is disrupted when actomyosin based tension was inhibited. Cells near the edge or corner of geometric shapes proliferate while cells within do not. Regions of higher rate of cell migration corresponded to regions of concentrated growth. These findings demonstrate that multicellular organization can result in spatial patterns of migration and proliferation.

  15. Leukemia: stem cells, maturation arrest, and differentiation therapy.

    PubMed

    Sell, Stewart

    2005-01-01

    Human myeloid leukemias provide models of maturation arrest and differentiation therapy of cancer. The genetic lesions of leukemia result in a block of differentiation (maturation arrest) that allows myeloid leukemic cells to continue to proliferate and/or prevents the terminal differentiation and apoptosis seen in normal white blood cells. In chronic myeloid leukemia, the bcr-abl (t9/22) translocation produces a fusion product that is an activated tyrosine kinase resulting in constitutive activation cells at the myelocyte level. This activation may be inhibited by imatinib mesylate (Gleevec, STI-571), which blocks the binding of ATP to the activated tyrosine kinase, prevents phosphorylation, and allows the leukemic cells to differentiate and undergo apoptosis. In acute promyelocytic leukemia, fusion of the retinoic acid receptor-alpha with the gene coding for promyelocytic protein, the PML-RAR alpha (t15:17) translocation, produces a fusion product that blocks the activity of the promyelocytic protein, which is required for formation of the granules of promyelocytes and prevents further differentiation. Retinoic acids bind to the retinoic acid receptor (RAR alpha) component of the fusion product, resulting in degradation of the fusion protein by ubiquitinization. This allows normal PML to participate in granule formation and differentiation of the promyelocytes. In one common type of acute myeloid leukemia, which results in maturation arrest at the myeloid precursor level, there is a mutation of FLT3, a transmembrane tyrosine kinase, which results in constitutive activation of the IL-3 receptor. This may be blocked by agents that inhibit farnesyl transferase. In each of these examples, specific inhibition of the genetically altered activation molecules of the leukemic cells allows the leukemic cells to differentiate and die. Because acute myeloid leukemias usually have mutation of more than one gene, combinations of specific inhibitors that act on the effects of

  16. ECHIDNA-mediated post-Golgi trafficking of auxin carriers for differential cell elongation.

    PubMed

    Boutté, Yohann; Jonsson, Kristoffer; McFarlane, Heather E; Johnson, Errin; Gendre, Delphine; Swarup, Ranjan; Friml, Jirí; Samuels, Lacey; Robert, Stéphanie; Bhalerao, Rishikesh P

    2013-10-01

    The plant hormone indole-acetic acid (auxin) is essential for many aspects of plant development. Auxin-mediated growth regulation typically involves the establishment of an auxin concentration gradient mediated by polarly localized auxin transporters. The localization of auxin carriers and their amount at the plasma membrane are controlled by membrane trafficking processes such as secretion, endocytosis, and recycling. In contrast to endocytosis or recycling, how the secretory pathway mediates the localization of auxin carriers is not well understood. In this study we have used the differential cell elongation process during apical hook development to elucidate the mechanisms underlying the post-Golgi trafficking of auxin carriers in Arabidopsis. We show that differential cell elongation during apical hook development is defective in Arabidopsis mutant echidna (ech). ECH protein is required for the trans-Golgi network (TGN)-mediated trafficking of the auxin influx carrier AUX1 to the plasma membrane. In contrast, ech mutation only marginally perturbs the trafficking of the highly related auxin influx carrier LIKE-AUX1-3 or the auxin efflux carrier PIN-FORMED-3, both also involved in hook development. Electron tomography reveals that the trafficking defects in ech mutant are associated with the perturbation of secretory vesicle genesis from the TGN. Our results identify differential mechanisms for the post-Golgi trafficking of de novo-synthesized auxin carriers to plasma membrane from the TGN and reveal how trafficking of auxin influx carriers mediates the control of differential cell elongation in apical hook development.

  17. Molecular regulation of plant cell wall extensibility

    NASA Technical Reports Server (NTRS)

    Cosgrove, D. J.

    1998-01-01

    Gravity responses in plants often involve spatial and temporal changes in cell growth, which is regulated primarily by controlling the ability of the cell wall to extend. The wall is thought to be a cellulose-hemicellulose network embedded in a hydrated matrix of complex polysaccharides and a small amount of structural protein. The wall extends by a form of polymer creep, which is mediated by expansins, a novel group of wall-loosening proteins. Expansins were discovered during a molecular dissection of the "acid growth" behavior of cell walls. Expansin alters the rheology of plant walls in profound ways, yet its molecular mechanism of action is still uncertain. It lacks detectable hydrolytic activity against the major components of the wall, but it is able to disrupt noncovalent adhesion between wall polysaccharides. The discovery of a second family of expansins (beta-expansins) sheds light on the biological role of a major group of pollen allergens and implies that expansins have evolved for diverse developmental functions. Finally, the contribution of other processes to wall extensibility is briefly summarized.

  18. Osteogenic differentiation of human dental papilla mesenchymal cells

    SciTech Connect

    Ikeda, Etsuko; Hirose, Motohiro . E-mail: motohiro-hirose@aist.go.jp; Kotobuki, Noriko; Shimaoka, Hideki; Tadokoro, Mika; Maeda, Masahiko; Hayashi, Yoshiko; Kirita, Tadaaki; Ohgushi, Hajime

    2006-04-21

    We isolated dental papilla from impacted human molar and proliferated adherent fibroblastic cells after collagenase treatment of the papilla. The cells were negative for hematopoietic markers but positive for CD29, CD44, CD90, CD105, and CD166. When the cells were further cultured in the presence of {beta}-glycerophosphate, ascorbic acid, and dexamethasone for 14 days, mineralized areas together with osteogenic differentiation evidenced by high alkaline phosphatase activity and osteocalcin contents were observed. The differentiation was confirmed at both protein and gene expression levels. The cells can also be cryopreserved and, after thawing, could show in vivo bone-forming capability. These results indicate that mesenchymal type cells localize in dental papilla and that the cells can be culture expanded/utilized for bone tissue engineering.

  19. Human embryonic stem cell derivation and directed differentiation.

    PubMed

    Trounson, A

    2005-01-01

    Human embryonic stem cells (hESCs) are produced from normal, chromosomally aneuploid and mutant human embryos, which are available from in vitro fertilisation (IVF) for infertility or preimplantation diagnosis. These hESC lines are an important resource for functional genomics, drug screening and eventually cell and gene therapy. The methods for deriving hESCs are well established and repeatable, and are relatively successful, with a ratio of 1:10 to 1:2 hESC lines established to embryos used. hESCs can be formed from morula and blastocyst-stage embryos and from isolated inner cell mass cell (ICM) clusters. The hESCs can be formed and maintained on mouse or human somatic cells in serum-free conditions, and for several passages in cell-free cultures. The hESCs can be transfected with DNA constructs. Their gene expression profiles are being described and immunological characteristics determined. They may be grown indefinitely in culture while maintaining their original karyotype but this must be confirmed from time to time. hESCs spontaneously differentiate in the absence of the appropriate cell feeder layer, when overgrown in culture and when isolated from the ESC colony. All three major embryonic lineages are produced in differentiating attachment cultures and in unattached embryoid bodies. Cell progenitors of interest can be identified by markers, expression of reporter genes and characteristic morphology, and the culture thereafter enriched for further culture to more mature cell types. The most advanced directed differentiation pathways have been developed for neural cells and cardiac muscle cells, but many other cell types including haematopoietic progenitors, endothelial cells, lung alveoli, keratinocytes, pigmented retinal epithelium, neural crest cells and motor neurones, hepatic progenitors and cells that have some markers of gut tissue and pancreatic cells have been produced. The prospects for regenerative medicine are significant and there is much

  20. PHOX2B Is Associated with Neuroblastoma Cell Differentiation.

    PubMed

    Yang, Liqun; Ke, Xiao-Xue; Xuan, Fan; Tan, Juan; Hou, Jianbing; Wang, Mei; Cui, Hongjuan; Zhang, Yundong

    2016-03-01

    Neuroblastoma is a common pediatric malignancy that accounts for ∼15% of tumor-related deaths in children. The tumor is generally believed to originate from neural crest cells during early sympathetic neurogenesis. As the degree of neuroblastoma differentiation has been correlated with clinical outcome, clarifying the molecular mechanisms that drive neuroblastoma progression and differentiation is important for increasing the survival of these patients. In a previous study, the authors identified paired-like homeobox 2b (PHOX2B) as a key mediator of neuroblastoma pathogenesis in a TH-MYCN mouse model. In the present study, they aimed to define whether PHOX2B is also associated with proliferation and differentiation of human neuroblastoma cells. PHOX2B expression in neuroblastoma cells was evaluated by immunoblot analyses, and the effects of PHOX2B on the proliferation of neuroblastoma cells in vitro were determined using clonogenic and sphere formation assays. Xenograft experiments in NOD/SCID mice were used to examine the in vivo response to PHOX2B knockdown. Their data demonstrated that PHOX2B acts as a prognostic marker in neuroblastoma and that retinoic acid-induced neuronal differentiation downregulates PHOX2B expression, thereby suppressing the self-renewal capacity of neuroblastoma cells and inhibiting tumorigenicity. These findings confirmed that PHOX2B is a key regulator of neuroblastoma differentiation and stemness maintenance and indicated that PHOX2B might serve as a potential therapeutic target in neuroblastoma patients.

  1. Inhibition of osteogenic differentiation of human mesenchymal stem cells

    PubMed Central

    Moioli, Eduardo K.; Hong, Liu; Mao, Jeremy J.

    2010-01-01

    Mesenchymal stem cells (hMSCs) have been shown to differentiate into osteoblasts that, in turn, are capable of forming tissues analogous to bone. The present study was designed to investigate the inhibition of osteogenesis by hMSCs. Bone marrow-derived hMSCs were treated with transforming growth factor β-3 (TGFβ3) at various doses during or after their differentiation into osteogenic cells. TGFβ3 was encapsulated in poly(DL-lactic-co-glycolic acid) (PLGA) microspheres and released via controlled delivery in the osteogenic culture of hMSCs and hMSC-derived osteoblasts for up to 28 days. Controlled release of TGFβ3 inhibited the osteogenic differentiation of hMSCs, as evidenced by significantly reduced alkaline phosphatase activity and staining, as well as decreased mineral deposition. After hMSCs had been differentiated into osteoblasts, controlled release of TGFβ3 further inhibited not only alkaline phosphatase and mineral deposition but also osteocalcin expression. These findings demonstrate the potential for sustained modulation of the behavior of stem cells and/or stem cell-derived lineage-specific cells via controlled release of growth factor(s). The attenuation of osteogenic differentiation of MSCs may facilitate understanding not only the regulation and patterning of osteogenesis in development but also several pathological models such as osteopetrosis, craniosynostosis, and heart valve calcification. PMID:17537129

  2. ERK signaling controls blastema cell differentiation during planarian regeneration.

    PubMed

    Tasaki, Junichi; Shibata, Norito; Nishimura, Osamu; Itomi, Kazu; Tabata, Yoshimichi; Son, Fuyan; Suzuki, Nobuko; Araki, Ryoko; Abe, Masumi; Agata, Kiyokazu; Umesono, Yoshihiko

    2011-06-01

    The robust regenerative ability of planarians depends on a population of somatic stem cells called neoblasts, which are the only mitotic cells in adults and are responsible for blastema formation after amputation. The molecular mechanism underlying neoblast differentiation associated with blastema formation remains unknown. Here, using the planarian Dugesia japonica we found that DjmkpA, a planarian mitogen-activated protein kinase (MAPK) phosphatase-related gene, was specifically expressed in blastema cells in response to increased extracellular signal-related kinase (ERK) activity. Pharmacological and genetic [RNA interference (RNAi)] approaches provided evidence that ERK activity was required for blastema cells to exit the proliferative state and undergo differentiation. By contrast, DjmkpA RNAi induced an increased level of ERK activity and rescued the differentiation defect of blastema cells caused by pharmacological reduction of ERK activity. These observations suggest that ERK signaling plays an instructive role in the cell fate decisions of blastema cells regarding whether to differentiate or not, by inducing DjmkpA as a negative regulator of ERK signaling during planarian regeneration.

  3. The focal differentiation of pigment cells.

    PubMed

    Whimster, I W

    1979-05-01

    A study has been made of the normal development and of the regeneration after excision of the groups of large pigment cells which form the spotted skin pattern of the gecko Eublepharis macularius, together with the effects of neonatal graft transplantation on this pattern. The results all indicate strongly that such groups of specialized pigment cells are not clones but the product of an induction process. This is then compared with the neural reflex mechanism by which the skin pattern of Chamaeoleo dilepis is formed.

  4. Coculture with embryonic stem cells improves neural differentiation of adipose tissue-derived stem cells.

    PubMed

    Bahmani, L; Taha, M F; Javeri, A

    2014-07-11

    Embryonic stem (ES) cells secrete some soluble factors which may affect the differentiation potential of adult stem cells toward different lineages. In the present study, we evaluated neural differentiation of mouse adipose tissue-derived stem cells (ADSCs) following coculture with ES cells. For this purpose, ADSCs were induced in a medium supplemented with a synthetic serum replacement and various concentrations of retinoic acid (RA). Then, third-passaged ADSCs were indirectly cocultured with ES cells, and the expression levels of pluripotency markers, OCT4 and Sox2, mesenchymal stem cell markers, CD73 and CD105, and proliferating cell nuclear antigen (PCNA), were assessed in the cocultured ADSCs. Moreover, the control and cocultured ADSCs were differentiated with or without RA treatment. We showed here that 2-week differentiated ADSCs expressed several neuron-specific genes, and RA treatment improved neural differentiation of the ADSCs. The expression levels of OCT4, Sox2 and PCNA were upregulated in the cocultured ADSCs. Moreover, coculture with the ES cells significantly improved neural differentiation of the ADSCs. Treatment of the cocultured ADSCs with RA diminished the expression of neural maturation markers. Coculture with the ES cells efficiently improves neural differentiation of the ADSCs. Non-contact coculture with the ES cells may be used as an efficient strategy to improve differentiation potential of adult stem cells for developmental studies and regenerative medicine.

  5. Stem cell origin of cancer and differentiation therapy.

    PubMed

    Sell, Stewart

    2004-07-01

    Our forefathers in pathology, on observing cancer tissue under the microscope in the mid-19th century, noticed the similarity between embryonic tissue and cancer, and suggested that tumors arise from embryo-like cells [Recherches dur le Traitement du Cancer, etc. Paris. (1829); Editoral Archiv fuer pathologische Anatomie und Physiologie und fuer klinische Medizin 8 (1855) 23]. The concept that adult tissues contain embryonic remnants that generally lie dormant, but that could be activated to become cancer was later formalized by Cohnheim [Path. Anat. Physiol. Klin. Med. 40 (1867) 1-79; Virchows Arch. 65 (1875) 64] and Durante [Arch. Memori ed Osservazioni di Chirugia Practica 11 (1874) 217-226], as the "embryonal rest" theory of cancer. An updated version of the embryonal rest theory of cancer is that cancers arise from tissue stem cells in adults. Analysis of the cellular origin of carcinomas of different organs indicates that there is, in each instance, a determined stem cell required for normal tissue renewal that is the most likely cell of origin of carcinomas [Lab. Investig. 70 (1994) 6-22]. In the present review, the nature of normal stem cells (embryonal, germinal and somatic) is presented and their relationships to cancer are further expanded. Cell signaling pathways shared by embryonic cells and cancer cells suggest a possible link between embryonic cells and cancer cells. Wilm's tumors (nephroblastomas) and neuroblastomas are presented as possible tumors of embryonic rests in children. Teratocarcinoma is used as the classic example of the totipotent cancer stem cell which can be influenced by its environment to differentiate into a mature adult cell. The observation that "promotion" of an epidermal cancer may be accomplished months or even years after the initial exposure to carcinogen ("initiation"), implies that the original carcinogenic event occurs in a long-lived epithelial stem cell population. The cellular events during hepatocarcinogenesis

  6. Engineering secondary cell wall deposition in plants

    PubMed Central

    Yang, Fan; Mitra, Prajakta; Zhang, Ling; Prak, Lina; Verhertbruggen, Yves; Kim, Jin-Sun; Sun, Lan; Zheng, Kejian; Tang, Kexuan; Auer, Manfred; Scheller, Henrik V; Loqué, Dominique

    2013-01-01

    Lignocellulosic biomass was used for thousands of years as animal feed and is now considered a great sugar source for biofuels production. It is composed mostly of secondary cell walls built with polysaccharide polymers that are embedded in lignin to reinforce the cell wall structure and maintain its integrity. Lignin is the primary material responsible for biomass recalcitrance to enzymatic hydrolysis. During plant development, deep reductions of lignin cause growth defects and often correlate with the loss of vessel integrity that adversely affects water and nutrient transport in plants. The work presented here describes a new approach to decrease lignin content while preventing vessel collapse and introduces a new strategy to boost transcription factor expression in native tissues. We used synthetic biology tools in Arabidopsis to rewire the secondary cell network by changing promoter-coding sequence associations. The result was a reduction in lignin and an increase in polysaccharide depositions in fibre cells. The promoter of a key lignin gene, C4H, was replaced by the vessel-specific promoter of transcription factor VND6. This rewired lignin biosynthesis specifically for vessel formation while disconnecting C4H expression from the fibre regulatory network. Secondly, the promoter of the IRX8 gene, secondary cell wall glycosyltransferase, was used to express a new copy of the fibre transcription factor NST1, and as the IRX8 promoter is induced by NST1, this also created an artificial positive feedback loop (APFL). The combination of strategies—lignin rewiring with APFL insertion—enhances polysaccharide deposition in stems without over-lignifying them, resulting in higher sugar yields after enzymatic hydrolysis. PMID:23140549

  7. Laser-induced fluorescence of green plants. I - A technique for the remote detection of plant stress and species differentiation

    NASA Technical Reports Server (NTRS)

    Chappelle, E. W.; Wood, F. M., Jr.; Mcmurtrey, J. E., III; Newcomb, W. W.

    1984-01-01

    The laser-induced fluorescence (LIF) of green plants was evaluated as a means of remotely detecting plant stress and determining plant type. Corn and soybeans were used as representatives of monocots and dicots, respectively, in these studies. The fluorescence spectra of several plant pigments was excited with a nitrogen laser emitting at 337 nm. Intact leaves from corn and soybeans also fluoresced using the nitrogen laser. The two plant species exhibited fluorescence spectra which had three maxima in common at 440, 690, and 740 nm. However, the relative intensities of these maxima were distinctly different for the two species. Soybeans had an additional slight maxima at 525 nm. Potassium deficiency in corn caused an increase in fluorescence at 690 and 740 nm. Simulated water stress in soybeans resulted in increased fluorescence at 440, 525, 690, and 740 nm. The inhibition of photosynthesis in soybeans by 3-(3-4-dichlorophenyl)-1-1-dimethyl urea (DCMU) gave incresed fluorescence primarily at 690 and 740 nm. Chlorosis as occurring in senescent soybean leaves caused a decrease in fluorescence at 690 and 740 nm. These studies indicate that LIF measurements of plants offer the potential for remotely detecting certain types of stress condition and also for differentiating plant species.

  8. The protease cathepsin L regulates Th17 cell differentiation.

    PubMed

    Hou, Lifei; Cooley, Jessica; Swanson, Richard; Ong, Poh Chee; Pike, Robert N; Bogyo, Matthew; Olson, Steven T; Remold-O'Donnell, Eileen

    2015-12-01

    Previously we reported that IL-17(+) T cells, primarily IL-17(+) γδ cells, are increased in mice lacking the protease inhibitor serpinB1 (serpinb1(-/-) mice). Here we show that serpinB1-deficient CD4 cells exhibit a cell-autonomous and selective deficiency in suppressing T helper 17 (Th17) cell differentiation. This suggested an opposing role for one or more protease in promoting Th17 differentiation. We found that several SerpinB1-inhibitable cysteine cathepsins are induced in Th17 cells, most prominently cathepsin L (catL); this was verified by peptidase assays, active site labeling and Western blots. Moreover, Th17 differentiation was suppressed by both broad cathepsin inhibitors and catL selective inhibitors. CatL is present in Th17 cells as single chain (SC)- and two-chain (TC)-forms. Inhibiting asparagine endopeptidase (AEP) blocked conversion of SC-catL to TC-catL and increased generation of serpinb1(-/-) Th17 cells, but not wild-type Th17 cells. These findings suggest that SC-catL is biologically active in promoting Th17 generation and is counter-regulated by serpinB1 and secondarily by AEP. Thus, in addition to regulation by cytokines and transcription factors, differentiation of CD4 cells to Th17 cells is actively regulated by a catL-serpinB1-AEP module. Targeting this protease regulatory module could be an approach to treating Th17 cell-driven autoimmune disorders.

  9. Glow in the dark: fluorescent proteins as cell and tissue-specific markers in plants.

    PubMed

    Ckurshumova, Wenzislava; Caragea, Adriana E; Goldstein, Rochelle S; Berleth, Thomas

    2011-09-01

    Since the hallmark discovery of Aequorea victoria's Green Fluorescent Protein (GFP) and its adaptation for efficient use in plants, fluorescent protein tags marking expression profiles or genuine proteins of interest have been used to recognize plant tissues and cell types, to monitor dynamic cell fate selection processes, and to obtain cell type-specific transcriptomes. Fluorescent tagging enabled visualization in living tissues and the precise recordings of dynamic expression pattern changes. The resulting accurate recording of cell fate acquisition kinetics in space and time has strongly stimulated mathematical modeling of self-organizing feedback mechanisms. In developmental studies, the use of fluorescent proteins has become critical, where morphological markers of tissues, cell types, or differentiation stages are either not known or not easily recognizable. In this review, we focus on the use of fluorescent markers to identify and illuminate otherwise invisible cell states in plant development.

  10. Regulation of endothelial cell differentiation and specification

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The circulatory system is the first organ system to develop in the vertebrate embryo and is critical throughout gestation for the delivery of oxygen and nutrients to, as well as removal of metabolic waste products from, growing tissues. Endothelial cells, which constitute the luminal layer of all bl...

  11. Effects of ionizing radiation on differentiation of murine bone marrow cells into mast cells.

    PubMed

    Murakami, Sho; Yoshino, Hironori; Ishikawa, Junya; Yamaguchi, Masaru; Tsujiguchi, Takakiyo; Nishiyama, Ayaka; Yokoyama, Kouki; Kashiwakura, Ikuo

    2015-11-01

    Mast cells, immune effector cells produced from bone marrow cells, play a major role in immunoglobulin E-mediated allergic responses. Ionizing radiation affects the functions of mast cells, which are involved in radiation-induced tissue damage. However, whether ionizing radiation affects the differential induction of mast cells is unknown. Here we investigated whether bone marrow cells of X-irradiated mice differentiated into mast cells. To induce mast cells, bone marrow cells from X-irradiated and unirradiated mice were cultured in the presence of cytokines required for mast cell induction. Although irradiation at 0.5 Gy and 2 Gy decreased the number of bone marrow cells 1 day post-irradiation, the cultured bone marrow cells of X-irradiated and unirradiated mice both expressed mast cell-related cell-surface antigens. However, the percentage of mast cells in the irradiated group was lower than in the unirradiated group. Similar decreases in the percentage of mast cells induced in the presence of X-irradiation were observed 10 days post irradiation, although the number of bone marrow cells in irradiated mice had recovered by this time. Analysis of mast cell function showed that degranulation of mast cells after immunoglobulin E-mediated allergen recognition was significantly higher in the X-irradiated group compared with in the unirradiated group. In conclusion, bone marrow cells of X-irradiated mice differentiated into mast cells, but ionizing radiation affected the differentiation efficiency and function of mast cells.

  12. Reactant pressure differential control for fuel cell gases

    NASA Technical Reports Server (NTRS)

    Grasso, A. P. (Inventor)

    1985-01-01

    A pair of spool valves are described which are balanced between pressures of reactant gases supplied to a fuel cell power plant. The pressure differences are controlled between the gases so as to maintain those pressures substantially in the proportions necessary for operation of the fuel cell.

  13. Optical quantification of forces at play during stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Ritter, Christine M.; Brickman, Joshua M.; Oddershede, Lene B.

    2016-03-01

    A cell is in constant interaction with its environment, it responds to external mechanical, chemical and biological signals. The response to these signals can be of various nature, for instance intra-cellular mechanical re-arrangements, cell-cell interactions, or cellular reinforcements. Optical methods are quite attractive for investigating the mechanics inside living cells as, e.g., optical traps are amongst the only nanotools that can reach and manipulate, measure forces, inside a living cell. In the recent years it has become increasingly evident that not only biochemical and biomolecular cues, but also that mechanical ones, play an important roles in stem cell differentiation. The first evidence for the importance of mechanical cues emerged from studies showing that substrate stiffness had an impact on stem cell differentiation. Recently, techniques such as optical tweezers and stretchers have been applied to stem cells, producing new insights into the role of mechanics in regulating renewal and differentiation. Here, we describe how optical tweezers and optical stretchers can be applied as a tool to investigate stem cell mechanics and some of the recent results to come out of this work.

  14. Differential effects of human and plant N-acetylglucosaminyltransferase I (GnTI) in plants.

    PubMed

    Henquet, Maurice; Heinhuis, Bas; Borst, Jan Willem; Eigenhuijsen, Jochem; Schreuder, Mariëlle; Bosch, Dirk; van der Krol, Alexander

    2010-08-01

    In plants and animals, the first step in complex type N-glycan formation on glycoproteins is catalyzed by N-acetylglucosaminyltransferase I (GnTI). We show that the cgl1-1 mutant of Arabidopsis, which lacks GnTI activity, is fully complemented by YFP-labeled plant AtGnTI, but only partially complemented by YFP-labeled human HuGnTI and that this is due to post-transcriptional events. In contrast to AtGnTI-YFP, only low levels of HuGnTI-YFP protein was detected in transgenic plants. In protoplast co-transfection experiments all GnTI-YFP fusion proteins co-localized with a Golgi marker protein, but only limited co-localization of AtGnTI and HuGnTI in the same plant protoplast. The partial alternative targeting of HuGnTI in plant protoplasts was alleviated by exchanging the membrane-anchor domain with that of AtGnTI, but in stably transformed cgl1-1 plants this chimeric GnTI still did not lead to full complementation of the cgl1-1 phenotype. Combined, the results indicate that activity of HuGnTI in plants is limited by a combination of reduced protein stability, alternative protein targeting and possibly to some extend to lower enzymatic performance of the catalytic domain in the plant biochemical environment.

  15. Interleukin-1 regulates proliferation and differentiation of oligodendrocyte progenitor cells.

    PubMed

    Vela, José M; Molina-Holgado, Eduardo; Arévalo-Martín, Angel; Almazán, Guillermina; Guaza, Carmen

    2002-07-01

    Interleukin-1 (IL-1) is a pleiotropic cytokine expressed during normal CNS development and in inflammatory demyelinating diseases, but remarkably little is known about its effect on oligodendroglial cells. In this study we explored the role of IL-1beta in oligodendrocyte progenitors and differentiated oligodendrocytes. The effects of IL-1beta were compared to those of IL-1 receptor antagonist, the specific inhibitor of IL-1 activity, since progenitors and differentiated oligodendrocytes produce IL-1beta and express IL-1 receptors. Unlike other proinflammatory cytokines (TNFalpha and IFNgamma), IL-1beta was not toxic for oligodendrocyte lineage cells. However, this cytokine inhibited proliferation of oligodendrocyte progenitors in the presence of growth factors (PDGF plus bFGF). This was evidenced by a significant decrease in both cells incorporating bromodeoxyuridine (45%) and total cell numbers (57%) after 6 days of treatment. Interestingly, IL-1beta blocked proliferation at the late progenitor/prooligodendrocyte (O4+) stage but did not affect proliferation of early progenitors (A2B5+). Inhibition of proliferation paralleled with promotion of differentiation, as revealed by the increased percentage of R-mab+ cells (6.7-fold). Moreover, when oligodendrocyte progenitors were allowed to differentiate in the absence of growth factors, treatment with IL-1beta promoted maturation to the MBP+ stage (4.2-fold) and survival of differentiating oligodendrocytes (2.1-fold). Regarding intracellular signaling, IL-1beta activated the p38 mitogen-activated protein kinase (MAPK) but not the p42/p44 MAPK and, when combined with growth factors, intensified p38 activation but inhibited the growth-factor-induced p42/p44 activation. IL-1beta also induced a time-dependent inhibition of PFGF-Ralpha gene expression. These results support a role for IL-1beta in promoting mitotic arrest and differentiation of oligodendrocyte progenitors as well as maturation and survival of differentiating

  16. Soybean proteome database: a data resource for plant differential omics.

    PubMed

    Sakata, Katsumi; Ohyanagi, Hajime; Nobori, Hiroya; Nakamura, Takuji; Hashiguchi, Akiko; Nanjo, Yohei; Mikami, Yoji; Yunokawa, Harunobu; Komatsu, Setsuko

    2009-07-01

    The Soybean Proteome Database aims to be a data repository for functional analyses of soybean responses to flooding injury, recognized as a major constraint for establishment and production of this plant. The current release contains 21 reference maps of soybean (Glycine max cv. Enrei) proteins electrophoresed on two-dimensional polyacrylamide gels of which the samples were collected from several organs, tissues and organelles. These reference maps include 7311 detected proteins and 532 identified proteins, or proteins for which a sequence or peptide peak has been determined. The database is searchable by protein properties such as accession number, description and isoelectric point and molecular weight range. The Soybean Proteome Database also integrates multiple "omes". An omics table reveals relationships among 106 mRNAs, 51 proteins and 89 metabolites that vary over time under flooding stress. The tabulated metabolites are anchored to a metabolome network. A unified temporal-profile tag attached to the mRNAs, proteins and metabolites facilitates retrieval of the data based on the temporal expression profiles. A graphical user interface based on dynamic HTML facilitates viewing the metabolome network as well as the profiles of multiple omes in a uniform manner. The entire database is available at http://proteome.dc.affrc.go.jp/Soybean/.

  17. The Role of Lymphatic Niches in T Cell Differentiation

    PubMed Central

    Capece, Tara; Kim, Minsoo

    2016-01-01

    Long-term immunity to many viral and bacterial pathogens requires CD8+ memory T cell development, and the induction of long-lasting CD8+ memory T cells from a naïve, undifferentiated state is a major goal of vaccine design. Formation of the memory CD8+ T cell compartment is highly dependent on the early activation cues received by naïve CD8+ T cells during primary infection. This review aims to highlight the cellularity of various niches within the lymph node and emphasize recent evidence suggesting that distinct types of T cell activation and differentiation occur within different immune contexts in lymphoid organs. PMID:27306645

  18. Dynamic simulation of a direct carbonate fuel cell power plant

    SciTech Connect

    Ernest, J.B.; Ghezel-Ayagh, H.; Kush, A.K.

    1996-12-31

    Fuel Cell Engineering Corporation (FCE) is commercializing a 2.85 MW Direct carbonate Fuel Cell (DFC) power plant. The commercialization sequence has already progressed through construction and operation of the first commercial-scale DFC power plant on a U.S. electric utility, the 2 MW Santa Clara Demonstration Project (SCDP), and the completion of the early phases of a Commercial Plant design. A 400 kW fuel cell stack Test Facility is being built at Energy Research Corporation (ERC), FCE`s parent company, which will be capable of testing commercial-sized fuel cell stacks in an integrated plant configuration. Fluor Daniel, Inc. provided engineering, procurement, and construction services for SCDP and has jointly developed the Commercial Plant design with FCE, focusing on the balance-of-plant (BOP) equipment outside of the fuel cell modules. This paper provides a brief orientation to the dynamic simulation of a fuel cell power plant and the benefits offered.

  19. Metabolic profiling of hematopoietic stem and progenitor cells during proliferation and differentiation into red blood cells.

    PubMed

    Daud, Hasbullah; Browne, Susan; Al-Majmaie, Rasoul; Murphy, William; Al-Rubeai, Mohamed

    2016-01-25

    An understanding of the metabolic profile of cell proliferation and differentiation should support the optimization of culture conditions for hematopoietic stem and progenitor cell (HSPC) proliferation, differentiation, and maturation into red blood cells. We have evaluated the key metabolic parameters during each phase of HSPC culture for red blood cell production in serum-supplemented (SS) and serum-free (SF) conditions. A simultaneous decrease in growth rate, total protein content, cell size, and the percentage of cells in the S/G2 phase of cell cycle, as well as an increase in the percentage of cells with a CD71(-)/GpA(+) surface marker profile, indicates HSPC differentiation into red blood cells. Compared with proliferating HSPCs, differentiating HSPCs showed significantly lower glucose and glutamine consumption rates, lactate and ammonia production rates, and amino acid consumption and production rates in both SS and SF conditions. Furthermore, extracellular acidification was associated with late proliferation phase, suggesting a reduced cellular metabolic rate during the transition from proliferation to differentiation. Under both SS and SF conditions, cells demonstrated a high metabolic rate with a mixed metabolism of both glycolysis and oxidative phosphorylation (OXPHOS) in early and late proliferation, an increased dependence on OXPHOS activity during differentiation, and a shift to glycolytic metabolism only during maturation phase. These changes indicate that cell metabolism may have an important impact on the ability of HSPCs to proliferate and differentiate into red blood cells.

  20. Random Monoallelic Gene Expression Increases upon Embryonic Stem Cell Differentiation

    PubMed Central

    Eckersley-Maslin, Mélanie A.; Thybert, David; Bergmann, Jan H.; Marioni, John C.; Flicek, Paul; Spector, David L.

    2014-01-01

    Summary Random autosomal monoallelic gene expression refers to the transcription of a gene from one of two homologous alleles. We assessed the dynamics of monoallelic expression during development through an allele-specific RNA sequencing screen in clonal populations of hybrid mouse embryonic stem cells (ESCs) and neural progenitor cells (NPCs). We identified 67 and 376 inheritable autosomal random monoallelically expressed genes in ESCs and NPCs respectively, a 5.6-fold increase upon differentiation. While DNA methylation and nuclear positioning did not distinguish the active and inactive alleles, specific histone modifications were differentially enriched between the two alleles. Interestingly, expression levels of 8% of the monoallelically expressed genes remained similar between monoallelic and biallelic clones. These results support a model in which random monoallelic expression occurs stochastically during differentiation, and for some genes is compensated for by the cell to maintain the required transcriptional output of these genes. PMID:24576421

  1. The effects of steel mutation on testicular germ cell differentiation.

    PubMed

    Nishimune, Y; Haneji, T; Kitamura, Y

    1980-10-01

    The effects of artificial cryptorchidism and its surgical reversal on spermatogenesis were examined in germ cell mutant, S1/+ and wild type, +/+, mice. In cryptorchid testes no difference was found between S1/+ and +/+ mice in the number of undifferentiated type A spermatogonia. The activity of type A spermatogonia in mutant mice appeared normal as judged by its mitotic cell number and DNA synthesis. The surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells in both types of mice, but the pattern of cellular differentiation in the mutant testes was completely different from that of the wild type testes. At two steps of cellular differentiation, intermediate or type B spermatogonia and spermatid, the numbers of cells were much smaller in the S1/+ testes than those in the +/+ testes. The steel gene was therefore suggested to exert its effects on the differentiation of type A spermatogonia to intermediate or type B spermatogonia, on meiotic division and/or the survival rate of these cells, but not on the undifferentiated type A spermatogonia or stem cells.

  2. Accumulation of differentiating intestinal stem cell progenies drives tumorigenesis

    PubMed Central

    Zhai, Zongzhao; Kondo, Shu; Ha, Nati; Boquete, Jean-Philippe; Brunner, Michael; Ueda, Ryu; Lemaitre, Bruno

    2015-01-01

    Stem cell self-renewal and differentiation are coordinated to maintain tissue homeostasis and prevent cancer. Mutations causing stem cell proliferation are traditionally the focus of cancer studies. However, the contribution of the differentiating stem cell progenies in tumorigenesis is poorly characterized. Here we report that loss of the SOX transcription factor, Sox21a, blocks the differentiation programme of enteroblast (EB), the intestinal stem cell progeny in the adult Drosophila midgut. This results in EB accumulation and formation of tumours. Sox21a tumour initiation and growth involve stem cell proliferation induced by the unpaired 2 mitogen released from accumulating EBs generating a feed-forward loop. EBs found in the tumours are heterogeneous and grow towards the intestinal lumen. Sox21a tumours modulate their environment by secreting matrix metalloproteinase and reactive oxygen species. Enterocytes surrounding the tumours are eliminated through delamination allowing tumour progression, a process requiring JNK activation. Our data highlight the tumorigenic properties of transit differentiating cells. PMID:26690827

  3. Cytotype differences modulate eco-geographical differentiation in the widespread plant Centaurea stoebe.

    PubMed

    Hahn, Min A; Müller-Schärer, Heinz

    2013-05-01

    The evolution of optimal life history strategies is central for the fitness of organisms in a given environment. Besides divergent selection, other factors may determine regional patterns of differentiation and contribute to life history evolution. In a common-garden environment over three years, we examined life history differentiation across different eco-geographical regions and effects of a specialist root-insect herbivore in the widespread European plant Centaurea stoebe, spotted knapweed. This plant occurs as two cytotypes with contrasting life cycles: monocarpic diploids and polycarpic tetraploids. In addition, the tetraploid cytotype has more recently become invasive in North America. We found significant regional differentiation in traits related to the timing of reproduction and reproductive allocation, but contrasting patterns in diploids and tetraploids. In diploids the degree of regional differentiation was higher compared to native tetraploids, and in the latter compared to invasive tetraploids. Furthermore, a pronounced shift in environmental conditions between the native and introduced range could have contributed to the differentiation between native and invasive tetraploids. The study also revealed the potential of the root-mining insect herbivore Agapeta zoegana, used as a biological control organism, to increase plant performance (presumably through overcompensatory growth), especially in the polycarpic tetraploids, and more so in the introduced populations. These findings suggest that patterns of regional differentiation in C. stoebe may be partly determined by divergent selection, but also strongly modulated by life cycle differences among geo-cytotypes. Furthermore, our study highlights the importance in applying a comprehensive and long-term approach when studying regional differentiation in plants.

  4. Surface topography during neural stem cell differentiation regulates cell migration and cell morphology.

    PubMed

    Czeisler, Catherine; Short, Aaron; Nelson, Tyler; Gygli, Patrick; Ortiz, Cristina; Catacutan, Fay Patsy; Stocker, Ben; Cronin, James; Lannutti, John; Winter, Jessica; Otero, José Javier

    2016-12-01

    We sought to determine the contribution of scaffold topography to the migration and morphology of neural stem cells by mimicking anatomical features of scaffolds found in vivo. We mimicked two types of central nervous system scaffolds encountered by neural stem cells during development in vitro by constructing different diameter electrospun polycaprolactone (PCL) fiber mats, a substrate that we have shown to be topographically similar to brain scaffolds. We compared the effects of large fibers (made to mimic blood vessel topography) with those of small-diameter fibers (made to mimic radial glial process topography) on the migration and differentiation of neural stem cells. Neural stem cells showed differential migratory and morphological reactions with laminin in different topographical contexts. We demonstrate, for the first time, that neural stem cell biological responses to laminin are dependent on topographical context. Large-fiber topography without laminin prevented cell migration, which was partially reversed by treatment with rock inhibitor. Cell morphology complexity assayed by fractal dimension was inhibited in nocodazole- and cytochalasin-D-treated neural precursor cells in large-fiber topography, but was not changed in small-fiber topography with these inhibitors. These data indicate that cell morphology has different requirements on cytoskeletal proteins dependent on the topographical environment encountered by the cell. We propose that the physical structure of distinct scaffolds induces unique signaling cascades that regulate migration and morphology in embryonic neural precursor cells. J. Comp. Neurol. 524:3485-3502, 2016. © 2016 Wiley Periodicals, Inc.

  5. Reversible Commitment to Differentiation by Human Multipotent Stromal Cells (MSCs) in Single-Cell Derived Colonies

    PubMed Central

    Ylöstalo, Joni; Bazhanov, Nikolay; Prockop, Darwin J

    2008-01-01

    Objective Human multipotent stromal cells (MSCs) readily form single-cell derived colonies when plated at clonal densities. However, the colonies are heterogeneous since the cells from a colony form new colonies that vary in size and differentiation potential when re-plated at clonal densities. The experiments here tested the hypothesis that the cells in the inner regions of colonies are partially differentiated but the differentiation is reversible. Materials and Methods Cells were separately isolated from the dense inner regions (IN) and less dense outer regions (OUT) of single-cell derived colonies. The cells were then compared by assays of their transcriptomes and proteins, and for clonogenicity and differentiation. Results The IN cells expressed fewer cell-cycle genes and higher levels of genes for extracellular matrix than the OUT cells. When transferred to differentiation medium, differentiation of the colonies occurred primarily in the IN regions. However, the IN cells were indistinguishable from OUT cells when re-plated at clonal densities and assayed for rates of propagation and clonogenicity. Also, the colonies formed by IN cells were similar to colonies formed by OUT cells in that they had distinct IN and OUT regions. Cultures of IN and OUT cells remained indistinguishable through multiple passages (30-75 population doublings), and both cells formed colonies that were looser and less dense as they were expanded. Conclusions The results demonstrated that the cells in the inner region of single-derived colonies are partially differentiated but the differentiation can be reversed by re-plating the cells at clonal densities. PMID:18619725

  6. Phytosphingosine promotes megakaryocytic differentiation of myeloid leukemia cells.

    PubMed

    Han, Sang Hee; Kim, Jusong; Her, Yerim; Seong, Ikjoo; Park, Sera; Bhattarai, Deepak; Jin, Guanghai; Lee, Kyeong; Chung, Gukhoon; Hwang, Sungkee; Bae, Yun Soo; Kim, Jaesang

    2015-12-01

    We report that phytosphingosine, a sphingolipid found in many organisms and implicated in cellular signaling, promotes megakaryocytic differentiation of myeloid leukemia cells. Specifically, phytosphingosine induced several hallmark changes associated with megakaryopoiesis from K562 and HEL cells including cell cycle arrest, cell size increase and polyploidization. We also confirmed that cell type specific markers of megakaryocytes, CD41a and CD42b are induced by phytosphingosine. Phospholipids with highly similar structures were unable to induce similar changes, indicating that the activity of phytosphingosine is highly specific. Although phytosphingosine is known to activate p38 MAPK-mediated apoptosis, the signaling mechanisms involved in megakaryopoiesis appear to be distinct. In sum, we present another model for dissecting molecular details of megakaryocytic differentiation which in large part remains obscure.

  7. Phytosphingosine promotes megakaryocytic differentiation of myeloid leukemia cells

    PubMed Central

    Han, Sang Hee; Kim, Jusong; Her, Yerim; Seong, Ikjoo; Park, Sera; Bhattarai, Deepak; Jin, Guanghai; Lee, Kyeong; Chung, Gukhoon; Hwang, Sungkee; Bae, Yun Soo; Kim, Jaesang

    2015-01-01

    We report that phytosphingosine, a sphingolipid found in many organisms and implicated in cellular signaling, promotes megakaryocytic differentiation of myeloid leukemia cells. Specifically, phytosphingosine induced several hallmark changes associated with megakaryopoiesis from K562 and HEL cells including cell cycle arrest, cell size increase and polyploidization. We also confirmed that cell type specific markers of megakaryocytes, CD41a and CD42b are induced by phytosphingosine. Phospholipids with highly similar structures were unable to induce similar changes, indicating that the activity of phytosphingosine is highly specific. Although phytosphingosine is known to activate p38 mitogen-activated protein kinase (MAPK)-mediated apoptosis, the signaling mechanisms involved in megakaryopoiesis appear to be distinct. In sum, we present another model for dissecting molecular details of megakaryocytic differentiation which in large part remains obscure. [BMB Reports 2015; 48(12): 691-695] PMID:26077028

  8. Motoneuron differentiation of immortalized human spinal cord cell lines.

    PubMed

    Li, R; Thode, S; Zhou, J; Richard, N; Pardinas, J; Rao, M S; Sah, D W

    2000-02-01

    Human motoneuron cell lines will be valuable tools for spinal cord research and drug discovery. To create such cell lines, we immortalized NCAM(+)/neurofilament(+) precursors from human embryonic spinal cord with a tetracycline repressible v-myc oncogene. Clonal NCAM(+)/neurofilament(+) cell lines differentiated exclusively into neurons within 1 week. These neurons displayed extensive processes, exhibited immunoreactivity for mature neuron-specific markers such as tau and synaptophysin, and fired action potentials upon current injection. Moreover, a clonal precursor cell line gave rise to multiple types of spinal cord neurons, including ChAT(+)/Lhx3(+)/Lhx4(+) motoneurons and GABA(+) interneurons. These neuronal restricted precursor cell lines will expedite the elucidation of molecular mechanisms that regulate the differentiation, maturation and survival of specific subsets of spinal cord neurons, and the identification and validation of novel drug targets for motoneuron diseases and spinal cord injury.

  9. Operational Optimization of Large-Scale Parallel-Unit SWRO Desalination Plant Using Differential Evolution Algorithm

    PubMed Central

    Wang, Xiaolong; Jiang, Aipeng; Jiangzhou, Shu; Li, Ping

    2014-01-01

    A large-scale parallel-unit seawater reverse osmosis desalination plant contains many reverse osmosis (RO) units. If the operating conditions change, these RO units will not work at the optimal design points which are computed before the plant is built. The operational optimization problem (OOP) of the plant is to find out a scheduling of operation to minimize the total running cost when the change happens. In this paper, the OOP is modelled as a mixed-integer nonlinear programming problem. A two-stage differential evolution algorithm is proposed to solve this OOP. Experimental results show that the proposed method is satisfactory in solution quality. PMID:24701180

  10. Differentiation of Human Embryonic Stem Cells on Periodontal Ligament Fibroblasts.

    PubMed

    Elçin, Y Murat; İnanç, Bülend; Elçin, A Eser

    2016-01-01

    Human embryonic stem cells' (hESCs) unlimited proliferative potential and differentiation capability to all somatic cell types makes them one of the potential cell sources in cell-based tissue engineering strategies as well as various experimental applications in fields such as developmental biology, pharmacokinetics, toxicology, and genetics. Periodontal tissue engineering is an approach to reconstitute the ectomesenchymally derived alveolar bone, periodontal ligament apparatus, and cementum tissues lost as a result of periodontal diseases. Cell-based therapies may offer potential advantage in overcoming the inherent limitations associated with contemporary regenerative procedures, such as dependency on defect type and size and the pool and capacity of progenitor cells resident in the wound area. Further elucidation of developmental mechanisms associated with tooth formation may also contribute to valuable knowledge based upon which the future therapies can be designed. Protocols for the differentiation of pluripotent hESCs into periodontal ligament fibroblastic cells (PDLF) as common progenitors for ligament, cementum, and alveolar bone tissue represent an initial step in developing hESC-based experimental and tissue engineering strategies. The present protocol describes methods associated with the guided differentiation of hESCs by the use of coculture with adult PDLFs and the resulting change of morphotype and phenotype of the pluripotent embryonic stem cells toward fibroblastic and osteoblastic lineages.

  11. Regulatory mechanisms of helper T cell differentiation

    PubMed Central

    Pappu, Bhanu P.; Angkasekwinai, Pornpimon; Dong, Chen

    2008-01-01

    Interleukin 17 (IL-17) family consists of six cytokines in mammals. Among them, IL-17 and IL-17F are expressed by a novel subset of CD4+ helper T (Th) cells and play critical function in inflammation and autoimmunity. On the other hand, IL-17E, also called IL-25, has been associated with allergic responses. Here we summarize recent work by us as well as other investigators in understanding the regulation and function of these three cytokines. From these studies, IL-17 family cytokines may serve as novel targets for pharmaceutical intervention of immune and inflammatory diseases. PMID:18280574

  12. Analysis of differentially expressed lncRNAs in differentiation of bone marrow stem cells into neural cells.

    PubMed

    Wu, Ai-Min; Ni, Wen-Fei; Huang, Zhe-Yu; Li, Qing-Long; Wu, Jian-Bo; Xu, Hua-Zi; Yin, Li-Hui

    2015-04-15

    Many studies have reported micro RNAs involved in the differentiation of bone marrow mesenchymal stem cells (BMSCs) into neural cells; however, the roles of long non-coding RNAs (lncRNAs) in the differentiation of BMSCs into neural cells remain poorly understood. We used microarray assays to compare the lncRNA and messenger RNA (mRNA) expression profiles in BMSCs and neural-induced BMSCs. We found a total of 24 lncRNAs and 738 mRNAs that were upregulated and 32 lncRNAs and 682 mRNAs that were downregulated in samples induced for 3h; 27 lncRNAs and 864 mRNAs that were upregulated and 37 lncRNAs and 968 mRNAs that were downregulated in 6h samples; and 23 lncRNAs and 1159 mRNAs that were upregulated or downregulated in both the 3h and 6h samples. For 23 differentially lncRNAs and 83 differentially mRNAs, 256 matched lncRNA-mRNA pairs were found. GO (Gene ontology) analysis showed that these lncRNAs were associated with biological processes, cellular components, and molecular functions. Twenty-five pathways were identified by pathway analysis. Then, RT-qPCR validation of the differentially expressed H19, Esco2, Pcdhb18, and RGD1560277 genes confirmed the microarray data. Our study revealed the expression patterns of lncRNAs in the differentiation of BMSCs into neural cells, and many lncRNAs were differentially expressed in induced BMSCs, suggesting that they may play key roles in processes of differentiation. Our findings may promote the use of BMSCs to treat neurodegenerative diseases and trauma.

  13. Differentiation of trophoblast cells from human embryonic stem cells: to be or not to be?

    PubMed

    Roberts, R Michael; Loh, Kyle M; Amita, Mitsuyoshi; Bernardo, Andreia S; Adachi, Katsuyuki; Alexenko, Andrei P; Schust, Danny J; Schulz, Laura C; Telugu, Bhanu Prakash V L; Ezashi, Toshihiko; Pedersen, Roger A

    2014-05-01

    It is imperative to unveil the full range of differentiated cell types into which human pluripotent stem cells (hPSCs) can develop. The need is twofold: it will delimit the therapeutic utility of these stem cells and is necessary to place their position accurately in the developmental hierarchy of lineage potential. Accumulated evidence suggested that hPSC could develop in vitro into an extraembryonic lineage (trophoblast (TB)) that is typically inaccessible to pluripotent embryonic cells during embryogenesis. However, whether these differentiated cells are truly authentic TB has been challenged. In this debate, we present a case for and a case against TB differentiation from hPSCs. By analogy to other differentiation systems, our debate is broadly applicable, as it articulates higher and more challenging standards for judging whether a given cell type has been genuinely produced from hPSC differentiation.

  14. DIFFERENTIATION IN N15 UPTAKE AND THE ORGANIZATION OF AN ARCTIC TUNDRA PLANT COMMUNITY

    EPA Science Inventory

    We used N15 soil-labeling techniques to examine how the dominant species in a N-limited, tussock tundra plant community partitioned soil N, and how such partitioning may contribute to community organization. The five most abundant species were well differentiated with respect to...

  15. Defining Developmental Potency and Cell Lineage Trajectories by Expression Profiling of Differentiating Mouse Embryonic Stem Cells

    PubMed Central

    Aiba, Kazuhiro; Nedorezov, Timur; Piao, Yulan; Nishiyama, Akira; Matoba, Ryo; Sharova, Lioudmila V.; Sharov, Alexei A.; Yamanaka, Shinya; Niwa, Hitoshi; Ko, Minoru S. H.

    2009-01-01

    Biologists rely on morphology, function and specific markers to define the differentiation status of cells. Transcript profiling has expanded the repertoire of these markers by providing the snapshot of cellular status that reflects the activity of all genes. However, such data have been used only to assess relative similarities and differences of these cells. Here we show that principal component analysis of global gene expression profiles map cells in multidimensional transcript profile space and the positions of differentiating cells progress in a stepwise manner along trajectories starting from undifferentiated embryonic stem (ES) cells located in the apex. We present three ‘cell lineage trajectories’, which represent the differentiation of ES cells into the first three lineages in mammalian development: primitive endoderm, trophoblast and primitive ectoderm/neural ectoderm. The positions of the cells along these trajectories seem to reflect the developmental potency of cells and can be used as a scale for the potential of cells. Indeed, we show that embryonic germ cells and induced pluripotent cells are mapped near the origin of the trajectories, whereas mouse embryo fibroblast and fibroblast cell lines are mapped near the far end of the trajectories. We suggest that this method can be used as the non-operational semi-quantitative definition of cell differentiation status and developmental potency. Furthermore, the global expression profiles of cell lineages provide a framework for the future study of in vitro and in vivo cell differentiation. PMID:19112179

  16. Role of Calcium and Calmodulin in Plant Cell Regulation

    NASA Technical Reports Server (NTRS)

    Cormier, M. J.

    1983-01-01

    The role of calcium and calmodulin in plant cell regulation is discussed. Experiments are done to discover the level of calcium in plants and animals. The effect of intracellular calcium on photosynthesis is discussed.

  17. Evolution and diversity of green plant cell walls.

    PubMed

    Popper, Zoë A

    2008-06-01

    Plant cells are surrounded by a dynamic cell wall that performs many essential biological roles, including regulation of cell expansion, the control of tissue cohesion, ion-exchange and defence against microbes. Recent evidence shows that the suite of polysaccharides and wall proteins from which the plant cell wall is composed shows variation between monophyletic plant taxa. This is likely to have been generated during the evolution of plant groups in response to environmental stress. Understanding the natural variation and diversity that exists between cell walls from different taxa is key to facilitating their future exploitation and manipulation, for example by increasing lignocellulosic content or reducing its recalcitrance for use in biofuel generation.

  18. Small Buccal Fat Pad Cells Have High Osteogenic Differentiation Potential.

    PubMed

    Tsurumachi, Niina; Akita, Daisuke; Kano, Koichiro; Matsumoto, Taro; Toriumi, Taku; Kazama, Tomohiko; Oki, Yoshinao; Tamura, Yoko; Tonogi, Morio; Isokawa, Keitaro; Shimizu, Noriyoshi; Honda, Masaki

    2016-03-01

    Dedifferentiated fat (DFAT) cells derived from mature adipocytes have mesenchymal stem cells' (MSCs) characteristics. Generally, mature adipocytes are 60-110 μm in diameter; however, association between adipocyte size and dedifferentiation efficiency is still unknown. This study, therefore, investigated the dedifferentiation efficiency of adipocytes based on cell diameter. Buccal fat pad was harvested from five human donors and dissociated by collagenase digestion. After exclusion of unwanted stromal cells by centrifugation, floating adipocytes were collected and their size distribution was analyzed. The floating adipocytes were then separated into two groups depending on cell size using 40- and 100-μm nylon mesh filters: cell diameters less than 40 μm (small adipocytes: S-adipocytes) and cell diameters of 40-100 μm (large adipocytes: L-adipocytes). Finally, we evaluated the efficiency of adipocyte dedifferentiation and then characterized the resultant DFAT cells. The S-adipocytes showed a higher capacity to dedifferentiate into DFAT cells (S-DFAT cells) compared to the L-adipocytes (L-DFAT cells). The S-DFAT cells also showed a relatively higher proportion of CD146-positive cells than L-DFAT cells, and exhibited more osteogenic differentiation ability based on the alkaline phosphatase activity and amount of calcium deposition. These results suggested that the S- and L-DFAT cells had distinct characteristics, and that the higher dedifferentiation potential of S-adipocytes compared to L-adipocytes gives the former group an advantage in yielding DFAT cells.

  19. Regulation of T Cell Differentiation and Function by EZH2

    PubMed Central

    Karantanos, Theodoros; Christofides, Anthos; Bardhan, Kankana; Li, Lequn; Boussiotis, Vassiliki A.

    2016-01-01

    The enhancer of zeste homolog 2 (EZH2), one of the polycomb-group proteins, is the catalytic subunit of Polycomb-repressive complex 2 (PRC2) and induces the trimethylation of the histone H3 lysine 27 (H3K27me3) promoting epigenetic gene silencing. EZH2 contains a SET domain promoting the methyltransferase activity, while the three other protein components of PRC2, namely EED, SUZ12, and RpAp46/48, induce compaction of the chromatin permitting EZH2 enzymatic activity. Numerous studies highlight the role of this evolutionary conserved protein as a master regulator of differentiation in humans involved in the repression of the homeotic gene and the inactivation of X-chromosome. Through its effects in the epigenetic regulation of critical genes, EZH2 has been strongly linked to cell cycle progression, stem cell pluripotency, and cancer biology, being currently at the cutting edge of research. Most recently, EZH2 has been associated with hematopoietic stem cell proliferation and differentiation, thymopoiesis and lymphopoiesis. Several studies have evaluated the role of EZH2 in the regulation of T cell differentiation and plasticity as well as its implications in the development of autoimmune diseases and graft-versus-host disease (GVHD). The aim of this review is to summarize the current knowledge regarding the role of EZH2 in the regulation of the differentiation and function of T cells focusing on possible applications in various immune-mediated conditions, including autoimmune disorders and GVHD. PMID:27199994

  20. The production and directed differentiation of human embryonic stem cells.

    PubMed

    Trounson, Alan

    2006-04-01

    Human embryonic stem cells (hESCs) are being rapidly produced from chromosomally euploid, aneuploid, and mutant human embryos that are available from in vitro fertilization clinics treating patients for infertility or preimplantation genetic diagnosis. These hESC lines are an important resource for functional genomics, drug screening, and, perhaps eventually, cell and gene therapy. The methods for deriving hESCs are well established and repeatable and are relatively successful with a ratio of 1:10 to 1:2 new hESC lines produced from 4- to 8-d-old morula and blastocysts and from isolated inner cell mass cell clusters of human blastocysts. The hESCs can be formed and maintained on human somatic cells in humanized serum-free culture conditions and for several passages in cell-free culture systems. The hESCs can be transfected with DNA constructs. Their gene expression profiles are being described and immunological characteristics determined. They may be grown indefinitely in vitro while maintaining their original karyotype and epigenetic status, but this needs to be confirmed from time to time in long-term cultures. hESCs spontaneously differentiate in the absence of the appropriate cell feeder layer, when overgrown in culture and when isolated from the ESC colony. All three major embryonic lineages are produced in differentiating flat attachment cultures and unattached embryoid bodies. Cell progenitors of interest can be identified by markers, expression of reporter genes, and characteristic morphology, and the cells thereafter enriched for progenitor types and further culture to more mature cell types. Directed differentiation systems are well developed for ectodermal pathways that result in neural and glial cells and the mesendodermal pathway for cardiac muscle cells and many other cell types including hematopoietic progenitors and endothelial cells. Directed differentiation into endoderm has been more difficult to achieve, perhaps because of the lack of markers of

  1. Cardiac stem cell niche, MMP9, and culture and differentiation of embryonic stem cells.

    PubMed

    Mishra, Paras Kumar; Kuypers, Nicholas John; Singh, Shree Ram; Leiberh, Noel Diaz; Chavali, Vishalakshi; Tyagi, Suresh C

    2013-01-01

    Embryonic stem cells (ESC) are totipotent, self-renewing, and clonogenic, having potential to differentiate into a wide variety of cell types. Due to regenerative capability, it has tremendous potential for treating myocardial infarction (death of myocardial tissue) and type 1 diabetes (death of pancreatic beta cells). Understanding the components regulating ESC differentiation is the key to unlock the regenerative potential of ESC-based therapies. Both the stiffness of extracellular matrix (ECM) and surrounding niche/microenvironment play pivotal roles in ESC differentiation. Matrix metalloproteinase-9 (MMP9) induces fibrosis that causes stiffness of the ECM and impairs differentiation of cardiac stem cells into cardiomyocytes. Here, we describe the method of ESC culture and differentiation, and the expression of MMP9 and its inhibitor, tissue inhibitor of metalloproteinase-4 (TIMP4) in differentiating ESC.

  2. NLRP3 inflammasome activation in mesenchymal stem cells inhibits osteogenic differentiation and enhances adipogenic differentiation.

    PubMed

    Wang, Linghao; Chen, Ke; Wan, Xinxing; Wang, Fang; Guo, Zi; Mo, Zhaohui

    2017-03-18

    Osteoporosis is one of the most common skeletal disease featured by osteopenia and adipose accumulation in bone tissue. NLRP3 inflammasome activation is an essential player in aging-related chronic diseases like osteoporosis, particularly due to the causal caspase-1 activation and its correlation to adipose accumulation in bone tissue. Moreover, the expression of anti-aging/senescence SIRT1 was reported to decline along with aging. As the major cellular contributor of bone formation, mesenchymal stem cells (MSCs) are multipotent stem cells processing mutually exclusive differentiatability toward osteocytes or adipocytes. Therefore, we hypothesized that NLRP3 inflammasome activation promotes adipogenesis and repress osteogenesis in MSCs via inhibiting SIRT1 expression. We activated NLRP3 inflammasome in human MSCs via lipopolysaccharide and palmitic acid (LPS/PA) treatment for self-renewal maintenance, adipogenic differentiation or osteogenic differentiation. LPS/PA treatment significantly increased NLRP3 expression, decreased SIRT1 expression and promoted caspase-1 activity in MSCs. LPS/PA treatment also boosted adipogenesis of MSCs and suppressed osteogenesis. Moreover, inhibition of caspase-1 activity repressed adipogenic differentiation and partially improved osteogenic differentiation of MSCs with LPS/PA treatment. Our study demonstrated the pivotal roles of NLRP3 inflammasome and downstream mediator caspase-1 for the progress of osteo-differentiation MSCs, and offered novel therapeutic target of treatment for osteoporosis.

  3. Oogenesis: single cell development and differentiation.

    PubMed

    Song, Jia L; Wong, Julian L; Wessel, Gary M

    2006-12-01

    Oocytes express a unique set of genes that are essential for their growth, for meiotic recombination and division, for storage of nutrients, and for fertilization. We have utilized the newly sequenced genome of Strongylocentrotus purpuratus to identify genes that help the oocyte accomplish each of these tasks. This study emphasizes four classes of genes that are specialized for oocyte function: (1) Transcription factors: many of these factors are not significantly expressed in embryos, but are shared by other adult tissues, namely the ovary, testis, and gut. (2) Meiosis: A full set of meiotic genes is present in the sea urchin, including those involved in cohesion, in synaptonemal complex formation, and in meiotic recombination. (3) Yolk uptake and storage: Nutrient storage for use during early embryogenesis is essential to oocyte function in most animals; the sea urchin accomplishes this task by using the major yolk protein and a family of accessory proteins called YP30. Comparison of the YP30 family members across their conserved, tandem fasciclin domains with their intervening introns reveals an incongruence in the evolution of its major clades. (4) Fertilization: This set of genes includes many of the cell surface proteins involved in sperm interaction and in the physical block to polyspermy. The majority of these genes are active only in oocytes, and in many cases, their anatomy reflects the tandem repeating interaction domains essential for the function of these proteins. Together, the expression profile of these four gene classes highlights the transitions of the oocyte from a stem cell precursor, through stages of development, to the clearing and re-programming of gene expression necessary to transition from oocyte, to egg, to embryo.

  4. Differentiating aquatic plant communities in a eutrophic river using hyperspectral and multispectral remote sensing

    USGS Publications Warehouse

    Tian, Y.Q.; Yu, Q.; Zimmerman, M.J.; Flint, S.; Waldron, M.C.

    2010-01-01

    This study evaluates the efficacy of remote sensing technology to monitor species composition, areal extent and density of aquatic plants (macrophytes and filamentous algae) in impoundments where their presence may violate water-quality standards. Multispectral satellite (IKONOS) images and more than 500 in situ hyperspectral samples were acquired to map aquatic plant distributions. By analyzing field measurements, we created a library of hyperspectral signatures for a variety of aquatic plant species, associations and densities. We also used three vegetation indices. Normalized Difference Vegetation Index (NDVI), near-infrared (NIR)-Green Angle Index (NGAI) and normalized water absorption depth (DH), at wavelengths 554, 680, 820 and 977 nm to differentiate among aquatic plant species composition, areal density and thickness in cases where hyperspectral analysis yielded potentially ambiguous interpretations. We compared the NDVI derived from IKONOS imagery with the in situ, hyperspectral-derived NDVI. The IKONOS-based images were also compared to data obtained through routine visual observations. Our results confirmed that aquatic species composition alters spectral signatures and affects the accuracy of remote sensing of aquatic plant density. The results also demonstrated that the NGAI has apparent advantages in estimating density over the NDVI and the DH. In the feature space of the three indices, 3D scatter plot analysis revealed that hyperspectral data can differentiate several aquatic plant associations. High-resolution multispectral imagery provided useful information to distinguish among biophysical aquatic plant characteristics. Classification analysis indicated that using satellite imagery to assess Lemna coverage yielded an overall agreement of 79% with visual observations and >90% agreement for the densest aquatic plant coverages. Interpretation of biophysical parameters derived from high-resolution satellite or airborne imagery should prove to be a

  5. PDK1 regulates B cell differentiation and homeostasis.

    PubMed

    Baracho, Gisele V; Cato, Matthew H; Zhu, Zilu; Jaren, Olav R; Hobeika, Elias; Reth, Michael; Rickert, Robert C

    2014-07-01

    Successful B cell differentiation and prevention of cell transformation depends on balanced and fine-tuned activation of cellular signaling pathways. The phosphatidyl inositol-3 kinase (PI3K) signaling pathway has emerged as a major regulator of B lymphocyte homeostasis and function. Phosphoinositide-dependent protein kinase-1 (PDK1) is the pivotal node in the PI3K pathway, regulating the stability and activity of downstream AGC kinases (including Akt, RSK, S6K, SGK, and PKC). Although the importance of PI3K activity in B cell differentiation is well documented, the role of PDK1 and other downstream effectors is underexplored. Here we used inducible and stage-specific gene targeting approaches to elucidate the role of PDK1 in early and peripheral B cell differentiation. PDK1 ablation enhanced cell cycle entry and apoptosis of IL-7-dependent pro-B cells, blocking Ig synthesis and B cell maturation. PDK1 also was essential for the survival and activation of peripheral B cells via regulation of PKC and Akt-dependent downstream effectors, such as GSK3α/β and Foxo1. We found that PDK1 deletion strongly impaired B cell receptor (BCR) signaling, but IL-4 costimulation was sufficient to restore BCR-induced proliferation. IL-4 also normalized PKCβ activation and hexokinase II expression in BCR-stimulated cells, suggesting that this signaling pathway can act independent of PDK1 to support B cell growth. In summary, our results demonstrate that PDK1 is indispensable for B cell survival, proliferation, and growth regulation.

  6. Cell responses to FGFR3 signalling: growth, differentiation and apoptosis

    SciTech Connect

    L'Hote, Corine G.M. . E-mail: Corine.LHote@cancer.org.uk; Knowles, Margaret A.

    2005-04-01

    FGFR3 is a receptor tyrosine kinase (RTK) of the FGF receptor family, known to have a negative regulatory effect on long bone growth. Fgfr3 knockout mice display longer bones and, accordingly, most germline-activating mutations in man are associated with dwarfism. Somatically, some of the same activating mutations are associated with the human cancers multiple myeloma, cervical carcinoma and carcinoma of the bladder. How signalling through FGFR3 can lead to either chondrocyte apoptosis or cancer cell proliferation is not fully understood. Although FGFR3 can be expressed as two main splice isoforms (IIIb or IIIc), there is no apparent link with specific cell responses, which may rather be associated with the cell type or its differentiation status. Depending on cell type, differential activation of STAT proteins has been observed. STAT1 phosphorylation seems to be involved in inhibition of chondrocyte proliferation while activation of the ERK pathway inhibits chondrocyte differentiation and B-cell proliferation (as in multiple myeloma). The role of FGFR3 in epithelial cancers (bladder and cervix) is not known. Some of the cell specificity may arise via modulation of signalling by crosstalk with other signalling pathways. Recently, inhibition of the ERK pathway in achondroplastic mice has provided hope for an approach to the treatment of dwarfism. Further understanding of the ability of FGFR3 to trigger different responses depending on cell type and cellular context may lead to treatments for both skeletal dysplasias and cancer.

  7. Differentiation state determines neural effects on microvascular endothelial cells

    SciTech Connect

    Muffley, Lara A.; Pan, Shin-Chen; Smith, Andria N.; Ga, Maricar; Hocking, Anne M.; Gibran, Nicole S.

    2012-10-01

    Growing evidence indicates that nerves and capillaries interact paracrinely in uninjured skin and cutaneous wounds. Although mature neurons are the predominant neural cell in the skin, neural progenitor cells have also been detected in uninjured adult skin. The aim of this study was to characterize differential paracrine effects of neural progenitor cells and mature sensory neurons on dermal microvascular endothelial cells. Our results suggest that neural progenitor cells and mature sensory neurons have unique secretory profiles and distinct effects on dermal microvascular endothelial cell proliferation, migration, and nitric oxide production. Neural progenitor cells and dorsal root ganglion neurons secrete different proteins related to angiogenesis. Specific to neural progenitor cells were dipeptidyl peptidase-4, IGFBP-2, pentraxin-3, serpin f1, TIMP-1, TIMP-4 and VEGF. In contrast, endostatin, FGF-1, MCP-1 and thrombospondin-2 were specific to dorsal root ganglion neurons. Microvascular endothelial cell proliferation was inhibited by dorsal root ganglion neurons but unaffected by neural progenitor cells. In contrast, microvascular endothelial cell migration in a scratch wound assay was inhibited by neural progenitor cells and unaffected by dorsal root ganglion neurons. In addition, nitric oxide production by microvascular endothelial cells was increased by dorsal root ganglion neurons but unaffected by neural progenitor cells. -- Highlights: Black-Right-Pointing-Pointer Dorsal root ganglion neurons, not neural progenitor cells, regulate microvascular endothelial cell proliferation. Black-Right-Pointing-Pointer Neural progenitor cells, not dorsal root ganglion neurons, regulate microvascular endothelial cell migration. Black-Right-Pointing-Pointer Neural progenitor cells and dorsal root ganglion neurons do not effect microvascular endothelial tube formation. Black-Right-Pointing-Pointer Dorsal root ganglion neurons, not neural progenitor cells, regulate

  8. A study on differentially expressed gene screening of Chrysanthemum plants under sound stress.

    PubMed

    Hongbo, Shao; Biao, Li; Bochu, Wang; Kun, Tang; Yilong, Liang

    2008-05-01

    Environmental stress can induce differential expression of genes of flower plants. It had been found that sound stimulation had an obvious effect on the growth and development of flower plants, but it is not reported on the differentially expressed genes and their expressing characteristics under sound stimulation. This is one of the few reports in terms of using the DDRT-PCR technique for screening the differentially expressed cDNA fragments responding to sound-wave stress on Chrysanthemum. Six differentially expressed cDNA fragments were obtained. Molecular weight of fragments was from 200 to 600 bp, respectively. Among differential fragments acquired, three of them (SA3, SG7-1, and CA2) were found to be positive fragments by northern dot hybridization, whose molecular weight are 270, 580 and 370 bp, respectively. SA3 was differentially expressed and SG7-1 was preferably expressed, while CA2 was restrained by the sound wave. These results indicated that expression of some genes was turned on, meanwhile the stress restrained some genes from expression under the mode of sound-stress stimulation.

  9. Chromatin assembly factor CAF-1 is required for cellular differentiation during plant development.

    PubMed

    Exner, Vivien; Taranto, Patti; Schönrock, Nicole; Gruissem, Wilhelm; Hennig, Lars

    2006-11-01

    Chromatin assembly factor CAF-1 facilitates the formation of nucleosomes on newly replicated DNA in vitro. However, the role of CAF-1 in development is poorly understood because mutants are not available in most multicellular model organisms. Biochemical evidence suggests that FASCIATA1, FASCIATA2 and MSI1 form CAF-1 in Arabidopsis thaliana. Because fasciata mutants are viable, CAF-1 is not essential for cell division in plants. Arabidopsis CAF-1 mutants have defects in shoot apical meristems; in addition, CAF-1 is required to establish seedling architecture, leaf size and trichome differentiation. CAF-1 is needed to restrict branching of trichomes on rosette leaves. Increased trichome branching in CAF-1 mutants is not strictly correlated with increased nuclear DNA content. In addition, fas2 glabra3 double mutants show an additive genetic interaction, demonstrating that CAF-1 acts genetically parallel to the GLABRA3-containing, endoreduplication-coupled trichome branching pathway. However, CAF-1 is often needed to restrict endoreduplication, because seedlings of most CAF-1 mutants have increased ploidy. Notably, in the Landsberg erecta background, loss of CAF-1 does not affect ploidy, demonstrating that loss of CAF-1 can be compensated in some Arabidopsis accessions. These results reveal that the functions of FAS1, FAS2 and MSI1 are not restricted to meristems, but are also needed to control genome replication at multiple steps of development.

  10. Expression of dystrophin Dp71 during PC12 cell differentiation.

    PubMed

    Cisneros, B; Rendon, A; Genty, V; Aranda, G; Marquez, F; Mornet, D; Montañez, C

    1996-08-02

    The expression of dystrophin-protein 71 (Dp71) was investigated during nerve growth factor (NGF) induced differentiation of PC12 cells. A semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay was designed to measure Dp71 mRNA, whereas the Dp71 protein amount was evaluated by immunoblot analysis using an anti-dystrophin monoclonal antibody. Comparison with control cultures showed that Dp71 mRNA and protein levels increased in parallel with NGF treatment peaking with increments of 60% and 1.4 times, respectively. The upregulation of Dp71 expression during PC12 cells differentiation point at PC12 cells as a suitable model for studying the function of Dp71 in neuronal cells.

  11. Roles of membrane trafficking in plant cell wall dynamics

    PubMed Central

    Ebine, Kazuo; Ueda, Takashi

    2015-01-01

    The cell wall is one of the characteristic components of plant cells. The cell wall composition differs among cell types and is modified in response to various environmental conditions. To properly generate and modify the cell wall, many proteins are transported to the plasma membrane or extracellular space through membrane trafficking, which is one of the key protein transport mechanisms in eukaryotic cells. Given the diverse composition and functions of the cell wall in plants, the transport of the cell wall components and proteins that are involved in cell wall-related events could be specialized for each cell type, i.e., the machinery for cell wall biogenesis, modification, and maintenance could be transported via different trafficking pathways. In this review, we summarize the recent progress in the current understanding of the roles and mechanisms of membrane trafficking in plant cells and focus on the biogenesis and regulation of the cell wall. PMID:26539200

  12. Ultrastructure of autophagy in plant cells: a review.

    PubMed

    van Doorn, Wouter G; Papini, Alessio

    2013-12-01

    Just as with yeasts and animal cells, plant cells show several types of autophagy. Microautophagy is the uptake of cellular constituents by the vacuolar membrane. Although microautophagy seems frequent in plants it is not yet fully proven to occur. Macroautophagy occurs farther away from the vacuole. In plants it is performed by autolysosomes, which are considerably different from the autophagosomes found in yeasts and animal cells, as in plants these organelles contain hydrolases from the onset of their formation. Another type of autophagy in plant cells (called mega-autophagy or mega-autolysis) is the massive degradation of the cell at the end of one type of programmed cell death (PCD). Furthermore, evidence has been found for autophagy during degradation of specific proteins, and during the internal degeneration of chloroplasts. This paper gives a brief overview of the present knowledge on the ultrastructure of autophagic processes in plants.

  13. Control of Differentiation of a Mammary Cell Line by Lipids

    NASA Astrophysics Data System (ADS)

    Dulbecco, Renato; Bologna, Mauro; Unger, Michael

    1980-03-01

    A rat mammary cell line (LA7) undergoes spontaneous differentiation into domes due to production of specific inducers by the cells. Some of these inducers may be lipids, and we show that lipids regulate this differentiation as both inducers and inhibitors. One inhibitor is the tumor promoter tetradecanoyl-13 phorbol 12-acetate. The inducers are saturated fatty acids of two groups: butyric acid and acids with chain lengths from C13 to C16, especially myristic acid (C14). Other inducers are myristoyl and palmitoyl lysolecithins, myristic acid methyl ester, and two cationic detergents with a tetradecenyl chain. We propose that the lipids with a C14-C16 alkyl chain affect differentiation by recognizing specific receptors through their alkyl chains and that the effects obtained depend on the head groups. These lipids may be physiological regulators in the mammary gland.

  14. In vivo differentiation of induced pluripotent stem cells into neural stem cells by chimera formation

    PubMed Central

    Choi, Hyun Woo; Hong, Yean Ju; Kim, Jong Soo; Song, Hyuk; Cho, Ssang Gu; Bae, Hojae; Kim, Changsung; Byun, Sung June; Do, Jeong Tae

    2017-01-01

    Like embryonic stem cells, induced pluripotent stem cells (iPSCs) can differentiate into all three germ layers in an in vitro system. Here, we developed a new technology for obtaining neural stem cells (NSCs) from iPSCs through chimera formation, in an in vivo environment. iPSCs contributed to the neural lineage in the chimera, which could be efficiently purified and directly cultured as NSCs in vitro. The iPSC-derived, in vivo-differentiated NSCs expressed NSC markers, and their gene-expression pattern more closely resembled that of fetal brain-derived NSCs than in vitro-differentiated NSCs. This system could be applied for differentiating pluripotent stem cells into specialized cell types whose differentiation protocols are not well established. PMID:28141814

  15. Inorganic arsenic impairs differentiation and functions of human dendritic cells

    SciTech Connect

    Macoch, Mélinda; Morzadec, Claudie; Fardel, Olivier; Vernhet, Laurent

    2013-01-15

    Experimental studies have demonstrated that the antileukemic trivalent inorganic arsenic prevents the development of severe pro-inflammatory diseases mediated by excessive Th1 and Th17 cell responses. Differentiation of Th1 and Th17 subsets is mainly regulated by interleukins (ILs) secreted from dendritic cells (DCs) and the ability of inorganic arsenic to impair interferon-γ and IL-17 secretion by interfering with the physiology of DCs is unknown. In the present study, we demonstrate that high concentrations of sodium arsenite (As(III), 1–2 μM) clinically achievable in plasma of arsenic-treated patients, block differentiation of human peripheral blood monocytes into immature DCs (iDCs) by inducing their necrosis. Differentiation of monocytes in the presence of non-cytotoxic concentrations of As(III) (0.1 to 0.5 μM) only slightly impacts endocytotic activity of iDCs or expression of co-stimulatory molecules in cells activated with lipopolysaccharide. However, this differentiation in the presence of As(III) strongly represses secretion of IL-12p70 and IL-23, two major regulators of Th1 and Th17 activities, from iDCs stimulated with different toll-like receptor (TLR) agonists in metalloid-free medium. Such As(III)-exposed DCs also exhibit reduced mRNA levels of IL12A and/or IL12B genes when activated with TLR agonists. Finally, differentiation of monocytes with non-cytotoxic concentrations of As(III) subsequently reduces the ability of activated DCs to stimulate the release of interferon-γ and IL-17 from Th cells. In conclusion, our results demonstrate that clinically relevant concentrations of inorganic arsenic markedly impair in vitro differentiation and functions of DCs, which may contribute to the putative beneficial effects of the metalloid towards inflammatory autoimmune diseases. Highlights: ► Inorganic arsenic impairs differentiation and functions of human dendritic cells (DCs) ► Arsenite (> 1 μM) blocks differentiation of dendritic cells by

  16. Zfp423 promotes adipogenic differentiation of bovine stromal vascular cells.

    PubMed

    Huang, Yan; Das, Arun Kr; Yang, Qi-Yuan; Zhu, Mei-Jun; Du, Min

    2012-01-01

    Intramuscular fat or marbling is critical for the palatability of beef. In mice, very recent studies show that adipocytes and fibroblasts share a common pool of progenitor cells, with Zinc finger protein 423 (Zfp423) as a key initiator of adipogenic differentiation. To evaluate the role of Zfp423 in intramuscular adipogenesis and marbling in beef cattle, we sampled beef muscle for separation of stromal vascular cells. These cells were immortalized with pCI neo-hEST2 and individual clones were selected by G418. A total of 288 clones (3×96 well plates) were isolated and induced to adipogenesis. The presence of adipocytes was assessed by Oil-Red-O staining. Three clones with high and low adipogenic potential respectively were selected for further analyses. In addition, fibro/adipogenic progenitor cells were selected using a surface marker, platelet derived growth factor receptor (PDGFR) α. The expression of Zfp423 was much higher (307.4±61.9%, P<0.05) in high adipogenic cells, while transforming growth factor (TGF)-β was higher (156.1±48.7%, P<0.05) in low adipogenic cells. Following adipogenic differentiation, the expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α (C/EBPα) were much higher (239.4±84.1% and 310.7±138.4%, respectively, P<0.05) in high adipogenic cells. Over-expression of Zfp423 in stromal vascular cells and cloned low adipogenic cells dramatically increased their adipogenic differentiation, accompanied with the inhibition of TGF-β expression. Zfp423 knockdown by shRNA in high adipogenic cells largely prevented their adipogenic differentiation. The differential regulation of Zfp423 and TGF-β between low and high adipogenic cells is associated with the DNA methylation in their promoters. In conclusion, data show that Zfp423 is a critical regulator of adipogenesis in stromal vascular cells of bovine muscle, and Zfp423 may provide a molecular target for enhancing intramuscular adipogenesis

  17. Immunological aspects of using plant cells as delivery vehicles for oral vaccines.

    PubMed

    Rosales-Mendoza, Sergio; Salazar-González, Jorge A

    2014-06-01

    Genetically engineered plants can be used for the biomanufacture and delivery of oral vaccines. Although a myriad of antigens have been produced using this approach, improving our knowledge of their oral immunogenic properties is a priority as this aspect has not been well researched. Some studies have provided evidence of a higher immunogenic activity for antigens that were orally administered in the form of plant-based vaccines in comparison with conventional pure antigens. The characteristics of the plant-derived vaccines that may influence oral immunogenicity are identified and discussed in this review. Among the hypotheses explaining these immunogenic properties are the following: bioencapsulation favors antigen uptake and displays a resistance to degradation; plant metabolites exert adjuvant activity; plant compounds, such as polysaccharides, exert mucoadhesive properties; differential glycosylation conferred by the plant cell machinery enhances immunogenicity. Perspectives on how these hypotheses may be assessed are examined.

  18. Surface Curvature Differentially Regulates Stem Cell Migration and Differentiation via Altered Attachment Morphology and Nuclear Deformation

    PubMed Central

    Werner, Maike; Blanquer, Sébastien B. G.; Haimi, Suvi P.; Korus, Gabriela; Dunlop, John W. C.; Duda, Georg N.; Grijpma, Dirk. W.

    2016-01-01

    Signals from the microenvironment around a cell are known to influence cell behavior. Material properties, such as biochemical composition and substrate stiffness, are today accepted as significant regulators of stem cell fate. The knowledge of how cell behavior is influenced by 3D geometric cues is, however, strongly limited despite its potential relevance for the understanding of tissue regenerative processes and the design of biomaterials. Here, the role of surface curvature on the migratory and differentiation behavior of human mesenchymal stem cells (hMSCs) has been investigated on 3D surfaces with well‐defined geometric features produced by stereolithography. Time lapse microscopy reveals a significant increase of cell migration speed on concave spherical compared to convex spherical structures and flat surfaces resulting from an upward‐lift of the cell body due to cytoskeletal forces. On convex surfaces, cytoskeletal forces lead to substantial nuclear deformation, increase lamin‐A levels and promote osteogenic differentiation. The findings of this study demonstrate a so far missing link between 3D surface curvature and hMSC behavior. This will not only help to better understand the role of extracellular matrix architecture in health and disease but also give new insights in how 3D geometries can be used as a cell‐instructive material parameter in the field of biomaterial‐guided tissue regeneration. PMID:28251054

  19. Gravity sensing mechanisms in plant cells.

    PubMed

    Sievers, A

    1991-07-01

    Sensing of gravity is essential for the survival of plant seedlings. Therefore it is understandable that gravistimulation of only 0.5 sec-duration causes a graviresponse. The earliest graviresponses could be measured within seconds as alterations in membrane potentials of the statocytes in the root cap. Root statocytes are polarly organized. From a 6-day microgravity (10(-3) - 10(-4) g) experiment in the Spacelab D1 Mission it has been concluded that the observed polar differentiation is a result of a genetically prepatterned developmental program. Statoliths, the sedimentable organelles of statocytes, are surrounded by actin filaments which partly keep them in position. Under 6 min of microgravity during parabolic flights of rockets it could be demonstrated that the statoliths moved in the opposite direction to the initial gravity vector. It is concluded that shearing forces are exerted by microfilaments. It is supposed that the change of the position of statoliths is transmitted to gravisensitive structures of the statocytes (ER, plasma membrane) via microfilaments. As graviperception is influenced by calcium ions, it is suggested that these interactions regulate the activity of ion channels and/or pumps in the membranes thus initiating the graviresponse chain. In the case of cytoplasmic streaming in Chara rhizoids, the endogenous difference between the opposing streaming directions is diminished under microgravity during the flights of rockets. Possibly, shear stresses are affected by gravity, thus inducing gravity-related differences in the streaming velocities via actin filaments.

  20. Generating pluripotent stem cells: differential epigenetic changes during cellular reprogramming.

    PubMed

    Tobin, Stacey C; Kim, Kitai

    2012-08-31

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)--derived by ectopic expression of four reprogramming factors in donor somatic cells--are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations.

  1. Polysulfide promotes neuroblastoma cell differentiation by accelerating calcium influx.

    PubMed

    Koike, Shin; Shibuya, Norihiro; Kimura, Hideo; Ishii, Kazuyuki; Ogasawara, Yuki

    2015-04-10

    Polysulfides are a typical type of bound sulfur, which is physiologically stable form of sulfur species, derived from the hydrogen sulfide (H2S) that is generated endogenously in cells. We previously reported that bound sulfur protects neuronal cells from oxidative injury. In the present study, we demonstrated that polysulfides inhibited cell growth and promoted neurite outgrowth in mouse neuroblastoma Neuro2A (N2A) cells. However, Na2S showed no effect on neurite outgrowth in N2A cells. Furthermore, 2-APB and SKF96365, which are typical transient receptor potential (TRP) channel inhibitors, suppressed the neurite outgrowth induced by Na2S4. These new findings suggest that bound sulfur could induce neurite outgrowth and cell differentiation of N2A cells by accelerating calcium influx.

  2. Role of endogenous cat retrovirus in cell differentiation.

    PubMed Central

    Rasheed, S

    1982-01-01

    Several long-term cultures were established from a spontaneous melanoma of a cat. Cells were rounded or spindle shaped and exhibited black/brown pigmentation in the cytoplasm. No virus was released from these cells spontaneously or after treatment with chemicals. However, exogenous infection of the cat melanoma cells with the endogenous cat virus RD114 resulted in remarkable morphological and functional changes. Most of the RD114 virus-infected cells exhibited multiple neuritic extensions and about 1-2% of the population showed characteristics of neuronal cells. Because human, mouse, and hamster melanoma cultures infected with various mammalian retroviruses, including the RD114 virus, did not display any morphological alteration, it is concluded that the neuronal cell differentiation in the cat melanoma cells is a consequence of its specific interaction with the endogenous cat retrovirus. Images PMID:6961415

  3. Transferrin is required for early T-cell differentiation.

    PubMed

    Macedo, M Fatima; de Sousa, Maria; Ned, Renee M; Mascarenhas, Claudia; Andrews, Nancy C; Correia-Neves, Margarida

    2004-08-01

    Transferrin, the major plasma iron carrier, mediates iron entry into cells through interaction with its receptor. Several in vitro studies have demonstrated that transferrin plays an essential role in lymphocyte division, a role attributed to its iron transport function. In the present study we used hypotransferrinaemic (Trf(hpx/hpx)) mice to investigate the possible involvement of transferrin in T lymphocyte differentiation in vivo. The absolute number of thymocytes was substantially reduced in Trf(hpx/hpx) mice, a result that could not be attributed to increased apoptosis. Moreover, the proportions of the four major thymic subpopulations were maintained and the percentage of dividing cells was not reduced. A leaky block in the differentiation of CD4(-) CD8(-) CD3(-) CD44(-) CD25(+) (TN3) into CD4(-) CD8(-) CD3(-) CD44(-) CD25(-) (TN4) cells was observed. In addition, a similar impairment of early thymocyte differentiation was observed in mice with reduced levels of transferrin receptor. The present study demonstrates, for the first time, that transferrin itself or a pathway triggered by the interaction of transferrin with its receptor is essential for normal early T-cell differentiation in vivo.

  4. Mitochondrial DNA replication during differentiation of murine embryonic stem cells.

    PubMed

    Facucho-Oliveira, Joao M; Alderson, Jon; Spikings, Emma C; Egginton, Stuart; St John, Justin C

    2007-11-15

    Oxidative phosphorylation (OXPHOS), the intracellular process that generates the majority of the ATP of a cell through the electron-transfer chain, is highly dependent on proteins encoded by the mitochondrial genome (mtDNA). MtDNA replication is regulated by the nuclear-encoded mitochondrial transcription factor A (TFAM) and the mitochondrial-specific DNA polymerase gamma, which consists of a catalytic (POLG) and an accessory (POLG2) subunit. Differentiation of pluripotent embryonic stem cells (ESCs) into specific cell types requires expansion of discrete populations of mitochondria and mtDNA replication to meet the specific metabolic requirements of the cell. We determined by real-time PCR that expression of pluripotent markers is reduced before the upregulation of Polg, Polg2 and Tfam in spontaneously differentiating R1 murine (m)ESCs, along with transient increases in mtDNA copy number. In D3 mESCs, the initial transient increase did not take place. However, precursors of neuronal and cardiomyocyte differentiation were positive for both POLG and TFAM. Similar-stage ESCs also showed active mtDNA replication, identified by 5-bromo-2'-deoxy-uridine labelling, as mtDNA copy number increased. Retinoic-acid-induced differentiation resulted in more consistent patterns of replication and upregulation of Polg, Polg2 and Tfam, whereas siRNA knockdown demonstrated that steady-state expression of POLG is essential for maintaining pluripotency.

  5. Auxin regulation of cell polarity in plants.

    PubMed

    Pan, Xue; Chen, Jisheng; Yang, Zhenbiao

    2015-12-01

    Auxin is well known to control pattern formation and directional growth at the organ/tissue levels via the nuclear TIR1/AFB receptor-mediated transcriptional responses. Recent studies have expanded the arena of auxin actions as a trigger or key regulator of cell polarization and morphogenesis. These actions require non-transcriptional responses such as changes in the cytoskeleton and vesicular trafficking, which are commonly regulated by ROP/Rac GTPase-dependent pathways. These findings beg for the question about the nature of auxin receptors that regulate these responses and renew the interest in ABP1 as a cell surface auxin receptor, including the work showing auxin-binding protein 1 (ABP1) interacts with the extracellular domain of the transmembrane kinase (TMK) receptor-like kinases in an auxin-dependent manner, as well as the debate on this auxin binding protein discovered about 40 years ago. This review highlights recent work on the non-transcriptional auxin signaling mechanisms underscoring cell polarity and shape formation in plants.

  6. Progesterone biotransformation by plant cell suspension cultures.

    PubMed Central

    Yagen, B; Gallili, G E; Mateles, R I

    1978-01-01

    Progesterone was converted to 5alpha-pregnane-3alpha-ol-20-one, delta4-pregnene-20alpha-ol-3-one, delta4-pregnene-14alpha-ol-3,20-dione, delta4-pregnene-7beta,14alpha-diol-3,20-dione, and delta4-pregnene-6beta,11alpha-diol-3,20-dione by cell cultures of Lycopersicon esculentum. Cell cultures of Capsicum frutescens (green) metabolized progesterone to delta4-pregnene-20alpha-ol-3-one in very high yield, and Vinca rosea yielded delta4-pregnene-20beta-ol-3-one and delta4-pregnene-14alpha-ol-3,20-dione. A stereospecific reduction of the keto groups and a double bond and stereospecific introduction of hydroxyl groups at the 6, 11, and 14 positions have been observed. The mono- and dihydroxylated progesterones have not previously been reported as metabolic products of progesterone by plant cell systems and represent de novo hydroxylation of a nonglycosylated steroid. PMID:697360

  7. Selenoprotein O deficiencies suppress chondrogenic differentiation of ATDC5 cells.

    PubMed

    Yan, Jidong; Fei, Yao; Han, Yan; Lu, Shemin

    2016-10-01

    Selenoprotein O (Sel O) is a selenium-containing protein, but its function is still unclear. In the present study, we observed that the mRNA and protein expression levels of Sel O increased during chondrogenic induction of ATDC5 cells. The effects of Sel O on chondrocyte differentiation were then examined through shRNA-mediated gene silencing technique. The expression of Sel O was significantly suppressed at both mRNA and protein levels in a stable cell line transfected with a Sel O-specific target shRNA construct. Thereafter, we demonstrated that Sel O deficiencies suppress chondrogenic differentiation of ATDC5 cells. Sel O deficiencies inhibited expression of chondrogenic gene Sox9, Col II, and aggrecan. Sel O-deficient cells also accumulated a few cartilage glycosaminoglycans (GAGs) and decreased the activity of alkaline phosphatase (ALP). In addition, Sel O deficiencies inhibited chondrocyte proliferation through delayed cell cycle progression by suppression of cyclin D1 expression. Moreover, Sel O deficiencies induced chondrocyte death through cell apoptosis. In summary, we describe the expression patterns and the essential roles of Sel O in chondrocyte viability, proliferation, and chondrogenic differentiation. Additionally, Sel O deficiency-mediated impaired chondrogenesis may illustrate the mechanisms of Se deficiency in the pathophysiological process of the endemic osteoarthropathy.

  8. Silk scaffolds with tunable mechanical capability for cell differentiation

    PubMed Central

    Bai, Shumeng; Han, Hongyan; Huang, Xiaowei; Xu, Weian; Kaplan, David L.; Zhu, Hesun; Lu, Qiang

    2015-01-01

    Bombyx mori silk fibroin is a promising biomaterial for tissue regeneration and is usually considered an “inert” material with respect to actively regulating cell differentiation due to few specific cell signaling peptide domains in the primary sequence and the generally stiffer mechanical properties due to crystalline content formed in processing. In the present study, silk fibroin porous 3D scaffolds with nanostructures and tunable stiffness were generated via a silk fibroin nanofiber-assisted lyophilization process. The silk fibroin nanofibers with high β-sheet content were added into the silk fibroin solutions to modulate the self-assembly, and to directly induce water-insoluble scaffold formation after lyophilization. Unlike previously reported silk fibroin scaffold formation processes, these new scaffolds had lower overall β-sheet content and softer mechanical properties for improved cell compatibility. The scaffold stiffness could be further tuned to match soft tissue mechanical properties, which resulted in different differentiation outcomes with rat bone marrow-derived mesenchymal stem cells towards myogenic and endothelial cells, respectively. Therefore, these silk fibroin scaffolds regulate cell differentiation outcomes due to their mechanical features. PMID:25858557

  9. Human pluripotent stem cell differentiation into authentic striatal projection neurons.

    PubMed

    Delli Carri, Alessia; Onorati, Marco; Castiglioni, Valentina; Faedo, Andrea; Camnasio, Stefano; Toselli, Mauro; Biella, Gerardo; Cattaneo, Elena

    2013-08-01

    Here we present the principles and steps of a protocol that we have recently developed for the differentiation of hES/iPS cells into the authentic human striatal projection medium spiny neurons (MSNs) that die in Huntington's Disease (HD). Authenticity is judged by the convergence of multiple features within individual cells. Our procedure lasts 80 days and couples neural induction via BMP/TGF-β inhibition with exposure to the developmental factors sonic hedgehog (SHH) and dickkopf1 (DKK-1) to drive ventral telencephalic specification, followed by terminal differentiation [1]. Authenticity of the resulting neuronal population is monitored by the appearance of FOXG1(+)/GSX2(+) progenitor cells of the lateral ganglionic eminence (LGE) at day 15-25 of differentiation, followed by appearance of CTIP2-, FOXP1- and FOXP2-positive cells at day 45. These precursor cells then mature into MAP2(+)/GABA(+) neurons with 20 % of them ultimately co-expressing the DARPP-32 and CTIP2 diagnostic markers and carrying electrophysiological properties expected for fully functional MSNs.The protocol is characterized by its replicability in at least three human pluripotent cell lines. Altogether this protocol defines a useful platform for in vitro developmental neurobiology studies, drug screening, and regenerative medicine approaches.

  10. Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells

    PubMed Central

    Chen, Xiu-Juan; Wang, Na; Yi, Peng-Fei; Song, Min; Zhang, Bo; Wang, Yu-Zhong; Liang, Qiu-Hua

    2016-01-01

    Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification. PMID:27589055

  11. The transcriptional landscape of αβ T cell differentiation.

    PubMed

    Mingueneau, Michael; Kreslavsky, Taras; Gray, Daniel; Heng, Tracy; Cruse, Richard; Ericson, Jeffrey; Bendall, Sean; Spitzer, Matthew H; Nolan, Garry P; Kobayashi, Koichi; von Boehmer, Harald; Mathis, Diane; Benoist, Christophe; Best, Adam J; Knell, Jamie; Goldrath, Ananda; Joic, Vladimir; Koller, Daphne; Shay, Tal; Regev, Aviv; Cohen, Nadia; Brennan, Patrick; Brenner, Michael; Kim, Francis; Nageswara Rao, Tata; Wagers, Amy; Heng, Tracy; Ericson, Jeffrey; Rothamel, Katherine; Ortiz-Lopez, Adriana; Mathis, Diane; Benoist, Christophe; Bezman, Natalie A; Sun, Joseph C; Min-Oo, Gundula; Kim, Charlie C; Lanier, Lewis L; Miller, Jennifer; Brown, Brian; Merad, Miriam; Gautier, Emmanuel L; Jakubzick, Claudia; Randolph, Gwendalyn J; Monach, Paul; Blair, David A; Dustin, Michael L; Shinton, Susan A; Hardy, Richard R; Laidlaw, David; Collins, Jim; Gazit, Roi; Rossi, Derrick J; Malhotra, Nidhi; Sylvia, Katelyn; Kang, Joonsoo; Kreslavsky, Taras; Fletcher, Anne; Elpek, Kutlu; Bellemare-Pelletier, Angelique; Malhotra, Deepali; Turley, Shannon

    2013-06-01

    The differentiation of αβT cells from thymic precursors is a complex process essential for adaptive immunity. Here we exploited the breadth of expression data sets from the Immunological Genome Project to analyze how the differentiation of thymic precursors gives rise to mature T cell transcriptomes. We found that early T cell commitment was driven by unexpectedly gradual changes. In contrast, transit through the CD4(+)CD8(+) stage involved a global shutdown of housekeeping genes that is rare among cells of the immune system and correlated tightly with expression of the transcription factor c-Myc. Selection driven by major histocompatibility complex (MHC) molecules promoted a large-scale transcriptional reactivation. We identified distinct signatures that marked cells destined for positive selection versus apoptotic deletion. Differences in the expression of unexpectedly few genes accompanied commitment to the CD4(+) or CD8(+) lineage, a similarity that carried through to peripheral T cells and their activation, demonstrated by mass cytometry phosphoproteomics. The transcripts newly identified as encoding candidate mediators of key transitions help define the 'known unknowns' of thymocyte differentiation.

  12. Osteogenic Differentiation of Mesenchymal Stem Cells in Defined Protein Beads

    PubMed Central

    Lund, Amanda W.; Bush, Jeff A.; Plopper, George E.; Stegemann, Jan P.

    2008-01-01

    There is a need to develop improved methods for directing and maintaining the differentiation of human mesenchymal stem cells (hMSC) for regenerative medicine. Here, we present a method for embedding cells in defined protein microenvironments for the directed osteogenic differentiation of hMSC. Composite matrices of collagen I and agarose were produced by emulsification and simultaneous polymerization in the presence of hMSC to produce 30–150 μm diameter hydrogel “beads.” The proliferation, morphology, osteogenic gene expression, and calcium deposition of hMSC in bead environments were compared to other two- and three-dimensional culture environments over 14–21 days in culture. Cells embedded within 40% collagen beads exhibited equivalent proliferation rates to those in gel disks, but showed upregulation of bone sialoprotein and increased calcium deposition over 2D controls. Osteocalcin gene expression was not changed in 3D beads and disks, while collagen type I gene expression was downregulated relative to cells in 2D culture. The hydrogel bead format allows controlled cell differentiation and is a cell delivery vehicle that may also enhance vascular invasion and host incorporation. Our results indicate that the application of such beads can be used to promote the osteogenic phenotype in hMSC, which is an important step toward using them in bone repair applications. PMID:18431753

  13. Differentiation: A Central Topic in Developmental and Cell Biology

    NASA Astrophysics Data System (ADS)

    Müller, W. A.

    The concept of "differentiation" encompasses all processes leading to differently specialized cell types, beginning with the progressive divergence of developmental pathways and ending with the successive programming and final elaboration of each particular cell type. Guidance and positional information are provided by external cues, by differentially allotted cytoplasmic determinants such as mRNA for transcription factors, and by cascades of intercellular signals. Eventually cell type specific selector genes, such as the muscle cell determining MyoD/myogenin genes and neural key genes (e.g., achaete scute-C, neurogenin), are switched on which control entire sets of subordinate effector genes. In multiplying cells "cell heredity" based on an epigenetic cellular memory enables transmission of the cell type determining program from parental to daughter cells. This memory can be based on autocatalytic self-activation of cell type specific selector genes and on the enduring action of gene groups such as the Polycomb and thrithorax complexes that code for proteins which bind to DNA sequences called cellular memory modules. These modules confer permanent accessibility (potentiation) or inaccessibility (silencing) upon many different gene loci on the chromosomes.

  14. Differential requirements for survivin in hematopoietic cell development.

    PubMed

    Gurbuxani, Sandeep; Xu, Yanfei; Keerthivasan, Ganesan; Wickrema, Amittha; Crispino, John D

    2005-08-09

    Although erythroid cells and megakaryocytes arise from a common progenitor, their terminal maturation follows very different paths; erythroid cells undergo cell-cycle exit and enucleation, whereas megakaryocytes continue to progress through the cell cycle but skip late stages of mitosis to become polyploid cells. In our efforts to identify genes that participate in this process, we discovered that survivin, a member of the inhibitor of apoptosis family that also has an essential role in cytokinesis, is differentially expressed during erythroid versus megakaryocyte development. Erythroid cells express survivin throughout their maturation, whereas megakaryocytes express approximately 4-fold lower levels of survivin mRNA and no detectable protein. To investigate the role of survivin in these lineages, we overexpressed or knocked down survivin from mouse bone marrow cells and then examined erythroid and megakaryocyte development. These studies revealed that overexpression of survivin antagonized megakaryocyte growth, maturation, and polyploidization but had no effect on erythroid development. This block in polyploidization was accompanied by increased expression of p21 and decreased expression of megakaryocyte genes such as von Willebrand factor and beta(1)-tubulin. In contrast, a reduction in survivin expression interfered with the formation of erythroid cells but not megakaryocytes. Last, consistent with the requirement for survivin in the survival of proliferating cells, survivin-deficient hematopoietic progenitors failed to give rise to either erythroid or megakaryocytic colonies. Together, these studies show that whereas survivin expression is essential for megakaryocyte and erythroid progenitors, its down-regulation is required for terminal differentiation of megakaryocytes.

  15. Pathways for epidermal cell differentiation via the homeobox gene GLABRA2: update on the roles of the classic regulator.

    PubMed

    Lin, Qing; Qing, Lin; Aoyama, Takashi

    2012-10-01

    Recent plant development studies have identified regulatory pathways for epidermal cell differentiation in Arabidopsis thaliana. Interestingly, some of such pathways contain transcriptional networks with a common structure in which the homeobox gene GLABLA2 (GL2) is downstream of the transactivation complex consisting of MYB, bHLH, and WD40 proteins. Here, we review the role of GL2 as an output device of the conserved network, and update the knowledge of epidermal cell differentiation pathways downstream of GL2. Despite the consistent position of GL2 within the network, its role in epidermal tissues varies; in the root epidermis, GL2 promotes non-hair cell differentiation after cell pattern formation, whereas in the leaf epidermis, it is likely to be involved in both pattern formation and differentiation of trichomes. GL2 expression levels act as quantitative factors for initiation of cell differentiation in the root and leaf epidermis; the quantity of hairless cells in non-root hair cell files is reduced by gl2 mutations in a semi-dominant manner, and entopically additive expression of GL2 and a heterozygous gl2 mutation increase and decrease the number of trichomes, respectively. Although few direct target genes have been identified, evidence from genetic and expression analyses suggests that GL2 directly regulates genes with various hierarchies in epidermal cell differentiation pathways.

  16. Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

    SciTech Connect

    Vaca, Pilar; Berna, Genoveva; Araujo, Raquel; Carneiro, Everardo M.; Bedoya, Francisco J.; Soria, Bernat; Martin, Franz

    2008-03-10

    The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice. Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells.

  17. Co-regulation of brassinosteroid biosynthesis-related genes during xylem cell differentiation.

    PubMed

    Yamamoto, Ryo; Fujioka, Shozo; Iwamoto, Kuninori; Demura, Taku; Takatsuto, Suguru; Yoshida, Shigeo; Fukuda, Hiroo

    2007-01-01

    To understand the regulatory mechanisms of brassinosteroid (BR) biosynthesis in specific plant developmental processes, we first investigated the accumulation profiles of BRs and sterols in xylem differentiation in a Zinnia culture. The amounts of many substances in the late C28 sterol biosynthetic pathway to campesterol (CR), such as episterol and 24-methylenecholesterol, as well as those in the BR-specific biosynthetic pathway from CR to brassinolide (BL), were elevated in close association with tracheary element differentiation. Among them, 6-deoxotyphasterol (6-deoxoTY) accumulated to unusually high levels within cells cultured in tracheary element-inductive medium, while castasterone (CS) was not elevated either within or outside cells. To identify the molecular basis of this co-up-regulation of BRs and C28 sterols, we isolated Zinnia genes for the key enzymes of BR biosynthesis, ZeSTE1, ZeDIM, ZeDWF4, ZeCPD1 and ZeCPD2. RNA gel blot analysis of these genes indicated a coordinated increase in transcripts for ZeSTE1, ZeDIM, ZeDWF4 and ZeCPD1, and a tracheary element differentiation-specific increase in transcripts for ZeDWF4 and ZeCPD1. In situ hybridization experiments of ZeDWF4 and ZeCPD1 mRNAs revealed their preferential accumulation in procambium cells, immature xylem cells and xylem parenchyma cells. These results suggest that BR biosynthesis during tracheary element differentiation may be regulated by the coordinated regulation of broad sterol biosynthesis and specific regulation of BR biosynthesis, which occurs in part by elevated transcript levels of genes encoding BR biosynthetic enzymes, specifically ZeDWF4 and ZeCPD1. These data provide new insights into the regulation of BR biosynthesis and BR signaling during plant development.

  18. The influence of clinorotation on root cell differentiation in Brassica Rapa seedlings

    NASA Astrophysics Data System (ADS)

    Kalinina, Yana

    2005-08-01

    In this work we present the results of anatomical and ultrastructural investigations of root apices of Brassica rapa 6-day old seedlings grown in the stationary conditions and under slow horizontal clinorotation. The main attention was paid to the structural and functional organization of cells non-specialized for gravity perception during their growth and differentiation in a root. It was shown a decrease in length of the root growth zone due to reduction of the cell number in cell files under clinorotation. We conclude that the meristem proliferation activity was depressed under clinorotation. Some ultrastructural rearrangements of mitochondria in the distal elongation zone (DEZ) and increasing of their partial volume per cell were also observed. It is assumed that these changes reflect the intensification of mitochondrium functional activity in a DEZ cortex cells during clinorotation. An analysis of the experimental results supposes plants sense disorientation in the gravitational field as a stress.

  19. Increased differentiation of Th22 cells in Hashimoto's thyroiditis.

    PubMed

    Bai, Xue; Sun, Jie; Wang, Weiwei; Shan, Zhongyan; Zheng, Hongzhi; Li, Yushu; Zhao, Yuhang; Gong, Ming; Teng, Weiping

    2014-01-01

    As Th22 subsets are identified, their involvement in the pathogenesis of numerous autoimmune diseases has become apparent. In this study, we investigated differentiation of Th22 cells in the autoimmune thyroid diseases including Hashimoto's thyroiditis (HT) and Graves' disease (GD). Besides, we also explored the involvement of Th22 cells in an iodine-induced autoimmune thyroiditis (AIT) model (i.e., NOD.H-2(h4) mice). In HT patients, we showed the level of circulating Th22 cells correlated with the level of serum IL-22, and was significantly higher than in GD patients and healthy control subjects. Levels of serum IL-6, a major Th22 cell differentiation effector, were also higher in HT, and correlated with Th22 cells concentration. Peripheral blood mononuclear cells isolated from HT patients produced larger amounts of IL-6 in vitro than did those isolated from other groups. Furthermore, unlike those from GD patients, T lymphocytes from HT patients showed an enhanced differentiation in vitro into Th22 cells in the presence of recombinant IL-6 and TNF-α. In addition, levels of circulating Th22 cells and titers of thyroid peroxidase antibody were positively correlated in HT patients. In NOD.H-2(h4) mice, higher numbers of Th22 cells were observed in the spleens of the AIT group, while splenocytes of this group also produced larger amounts of IL-6 and IL-22 in vitro compared with the control. Intra-thyroid infiltrating IL-22+ lymphocytes were significantly increased in mice of the AIT group compared with the control. Our results indicate that Th22 cells may contribute to the pathogenesis of HT.

  20. Limbal Stromal Tissue Specific Stem Cells and Their Differentiation Potential to Corneal Epithelial Cells.

    PubMed

    Katikireddy, Kishore Reddy; Jurkunas, Ula V

    2016-01-01

    From the derivation of the first human embryonic stem (hES) cell line to the development of induced pluripotent stem (iPS) cells; it has become evident that tissue specific stem cells are able to differentiate into a specific somatic cell types. The understanding of key processes such as the signaling pathways and the role of the microenvironment in epidermal/epithelial development has provided important clues for the derivation of specific epithelial cell types.Various differentiation protocols/methods were used to attain specific epithelial cell types. Here, we describe in detail the procedure to follow for isolation of tissue specific stem cells, mimicking their microenvironment to attain stem cell characteristics, and their potential differentiation to corneal epithelial cells.

  1. The Vast Universe of T Cell Diversity: Subsets of Memory Cells and Their Differentiation.

    PubMed

    Jandus, Camilla; Usatorre, Amaia Martínez; Viganò, Selena; Zhang, Lianjun; Romero, Pedro

    2017-01-01

    The T cell receptor confers specificity for antigen recognition to T cells. By the first encounter with the cognate antigen, reactive T cells initiate a program of expansion and differentiation that will define not only the ultimate quantity of specific cells that will be generated, but more importantly their quality and functional heterogeneity. Recent achievements using mouse model infection systems have helped to shed light into the complex network of factors that dictate and sustain memory T cell differentiation, ranging from antigen load, TCR signal strength, metabolic fitness, transcriptional programs, and proliferative potential. The different models of memory T cell differentiation are discussed in this chapter, and key phenotypic and functional attributes of memory T cell subsets are presented, both for mouse and human cells. Therapeutic manipulation of memory T cell generation is expected to provide novel unique ways to optimize current immunotherapies, both in infection and cancer.

  2. How do plants achieve immunity? Defence without specialized immune cells.

    PubMed

    Spoel, Steven H; Dong, Xinnian

    2012-01-25

    Vertebrates have evolved a sophisticated adaptive immune system that relies on an almost infinite diversity of antigen receptors that are clonally expressed by specialized immune cells that roam the circulatory system. These immune cells provide vertebrates with extraordinary antigen-specific immune capacity and memory, while minimizing self-reactivity. Plants, however, lack specialized mobile immune cells. Instead, every plant cell is thought to be capable of launching an effective immune response. So how do plants achieve specific, self-tolerant immunity and establish immune memory? Recent developments point towards a multilayered plant innate immune system comprised of self-surveillance, systemic signalling and chromosomal changes that together establish effective immunity.

  3. Induced Pluripotent Stem (iPS) Cell Culture Methods and Induction of Differentiation into Endothelial Cells.

    PubMed

    Chatterjee, Ishita; Li, Fei; Kohler, Erin E; Rehman, Jalees; Malik, Asrar B; Wary, Kishore K

    2016-01-01

    The study of stem cell behavior and differentiation in a developmental context is complex, time-consuming, and expensive, and for this reason, cell culture remains a method of choice for developmental and regenerative biology and mechanistic studies. Similar to ES cells, iPS cells have the ability to differentiate into endothelial cells (ECs), and the route for differentiation appears to mimic the developmental process that occurs during the formation of an embryo. Traditional EC induction methods from embryonic stem (ES) cells rely mostly on the formation of embryoid body (EB), which employs feeder or feeder-free conditions in the presence or absence of supporting cells. Similar to ES cells, iPS cells can be cultured in feeder layer or feeder-free conditions. Here, we describe the iPS cell culture methods and induction differentiation of these cells into ECs. We use anti-mouse Flk1 and anti-mouse VE-cadherin to isolate and characterize mouse ECs, because these antibodies are commercially available and their use has been described in the literature, including by our group. The ECs produced by this method have been used by our laboratory, and we have demonstrated their in vivo potential. We also discuss how iPS cells differ in their ability to differentiate into endothelial cells in culture.

  4. Aquaporin 2-labeled cells differentiate to intercalated cells in response to potassium depletion.

    PubMed

    Kim, Wan-Young; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Kim, Yong Kyun; Kim, Jin

    2016-01-01

    The mammalian renal collecting duct consists of principal cells (PCs) and intercalated cells (ICs). Both PCs and ICs are involved in potassium (K(+)) homeostasis, PCs through their role in K(+) secretion and ICs through their ability to facilitate K(+) resorption. We previously hypothesized that PCs may differentiate into ICs upon K(+) depletion. However, no direct evidence has yet been obtained to conclusively demonstrate that PCs differentiate into ICs in response to K(+) depletion. Here, we present direct evidence for the differentiation of PCs into ICs by cell lineage tracing using aquaporin 2 (AQP2)-Cre mice and R26R-EYFP transgenic mice. In control mice, AQP2-EYFP(+) cells exhibited mainly a PC phenotype (AQP2-positive/H(+)-ATPase-negative). Interestingly, some AQP2-EYFP(+) cells exhibited an IC phenotype (H(+)-ATPase-positive/AQP2-negative); these cells accounted for 1.7 %. After K(+) depletion, the proportion of AQP2-EYFP(+) cells with an IC phenotype was increased to 4.1 %. Furthermore, some AQP2-EYFP(+) cells exhibited a "null cell" phenotype (AQP2-negative/H(+)-ATPase-negative) after K(+) depletion. Collectively, our data demonstrate that AQP2-labeled cells can differentiate into ICs, as well as null cells, in response to K(+) depletion. This finding indicates that some of AQP2-labeled cells possess properties of progenitor cells and that they can differentiate into ICs in the adult mouse kidney.

  5. Induced Pluripotent Stem (iPS) Cell Culture Methods and Induction of Differentiation into Endothelial Cells

    PubMed Central

    Chatterjee, Ishita; Li, Fei; Kohler, Erin E.; Rehman, Jalees; Malik, Asrar B.; Wary, Kishore K.

    2015-01-01

    Summary The studies of stem cell behavior and differentiation in a developmental context is complex, time-consuming and expensive, and for this reason, cell culture remains a method of choice for developmental and regenerative biology and mechanistic studies. Similar to ES cells, iPS cells have the ability to differentiate into endothelial cells (ECs), and the route for differentiation appears to mimic the developmental process that occurs during the formation of an embryo. Traditional EC induction methods from embryonic stem (ES) cells rely mostly on the formation the embryoid body (EB), which employs feeder or feeder-free conditions in the presence or absence of supporting cells. Similar to ES cells, iPS cells can be cultured in feeder-layer or feeder-free conditions. Here, we describe the iPS cell culture methods and induction differentiation of these cells into ECs. We use anti-mouse Flk1 and anti-mouse VE-cadherin to isolate and characterize mouse ECs, because these antibodies are commercially available and their use has been described in the literature, including by our group. The ECs produced by this method have been used by our laboratory, and we have demonstrated their in vivo potential. We also discuss how iPS cells differ in their ability to differentiate into endothelial cells in culture. PMID:25687301

  6. Effect of silver nanoparticles on human mesenchymal stem cell differentiation

    PubMed Central

    Diendorf, Jörg; Epple, Matthias; Schildhauer, Thomas A; Köller, Manfred

    2014-01-01

    Summary Background: Silver nanoparticles (Ag-NP) are one of the fastest growing products in nano-medicine due to their enhanced antibacterial activity at the nanoscale level. In biomedicine, hundreds of products have been coated with Ag-NP. For example, various medical devices include silver, such as surgical instruments, bone implants and wound dressings. After the degradation of these materials, or depending on the coating technique, silver in nanoparticle or ion form can be released and may come into close contact with tissues and cells. Despite incorporation of Ag-NP as an antibacterial agent in different products, the toxicological and biological effects of silver in the human body after long-term and low-concentration exposure are not well understood. In the current study, we investigated the effects of both ionic and nanoparticulate silver on the differentiation of human mesenchymal stem cells (hMSCs) into adipogenic, osteogenic and chondrogenic lineages and on the secretion of the respective differentiation markers adiponectin, osteocalcin and aggrecan. Results: As shown through laser scanning microscopy, Ag-NP with a size of 80 nm (hydrodynamic diameter) were taken up into hMSCs as nanoparticulate material. After 24 h of incubation, these Ag-NP were mainly found in the endo-lysosomal cell compartment as agglomerated material. Cytotoxicity was observed for differentiated or undifferentiated hMSCs treated with high silver concentrations (≥20 µg·mL−1 Ag-NP; ≥1.5 µg·mL−1 Ag+ ions) but not with low-concentration treatments (≤10 µg·mL−1 Ag-NP; ≤1.0 µg·mL−1 Ag+ ions). Subtoxic concentrations of Ag-NP and Ag+ ions impaired the adipogenic and osteogenic differentiation of hMSCs in a concentration-dependent manner, whereas chondrogenic differentiation was unaffected after 21 d of incubation. In contrast to aggrecan, the inhibitory effect of adipogenic and osteogenic differentiation was confirmed by a decrease in the secretion of specific

  7. Placozoa and the evolution of Metazoa and intrasomatic cell differentiation.

    PubMed

    Schierwater, Bernd; de Jong, Danielle; Desalle, Rob

    2009-02-01

    The multicellular Metazoa evolved from single-celled organisms (Protozoa) and usually - but not necessarily - consist of more cells than Protozoa. In all cases, and thus by definition, Metazoa possess more than one somatic cell type, i.e. they show-in sharp contrast to protists-intrasomatic differentiation. Placozoa have the lowest degree of intrasomatic variation; the number of somatic cell types according to text books is four (but see also Jakob W, Sagasser S, Dellaporta S, Holland P, Kuhn K, and Schierwater B. The Trox-2 Hox/ParaHox gene of Trichoplax (Placozoa) marks an epithelial boundary. Dev Genes Evol 2004;214:170-5). For this and several other reasons Placozoa have been regarded by many as the most basal metazoan phylum. Thus, the morphologically most simply organized metazoan animal, the placozoan Trichoplax adhaerens, resembles a unique model system for cell differentiation studies and also an intriguing model for a prominent "urmetazoon" hypotheses-the placula hypothesis. A basal position of Placozoa would provide answers to several key issues of metazoan-specific inventions (including for example different lines of somatic cell differentiation leading to organ development and axis formation) and would determine a root for unraveling their evolution. However, the phylogenetic relationships at the base of Metazoa are controversial and a basal position of Placozoa is not generally accepted (e.g. Schierwater B, DeSalle R. Can we ever identify the Urmetazoan? Integr Comp Biol 2007;47:670-76; DeSalle R, Schierwater B. An even "newer" animal phylogeny. Bioessays 2008;30:1043-47). Here we review and discuss (i) long-standing morphological evidence for the simple placozoan bauplan resembling an ancestral metazoan stage, (ii) some rapidly changing alternative hypotheses derived from molecular analyses, (iii) the surprising idea that triploblasts (Bilateria) and diploblasts may be sister groups, and (iv) the presence of genes involved in cell differentiation and

  8. Angiotensin II directly impairs adipogenic differentiation of human preadipose cells.

    PubMed

    Palominos, Marisol M; Dünner, Natalia H; Wabitsch, Martin; Rojas, Cecilia V

    2015-10-01

    Angiotensin II reduces adipogenic differentiation of preadipose cells present in the stroma-vascular fraction of human adipose tissue, which also includes several cell types. Because of the ability of non-adipose lineage cells in the stroma-vascular fraction to respond to angiotensin II, it is not possible to unequivocally ascribe the anti-adipogenic response to a direct effect of this hormone on preadipose cells. Therefore, we used the human Simpson-Golabi-Behmel syndrome (SGBS) preadipocyte cell strain to investigate the consequences of angiotensin II treatment on adipogenic differentiation under serum-free conditions, by assessing expression of typical adipocyte markers perilipin and fatty acid-binding protein 4 (FABP4), at the transcript and protein level. Reverse transcription-polymerase chain reaction showed that perilipin and FABP4 transcripts were, respectively, reduced to 0.33 ± 0.07 (P < 0.05) and 0.41 ± 0.19-fold (P < 0.05) in SGBS cells induced to adipogenic differentiation in the presence of angiotensin II. Western Blot analysis corroborated reduction of the corresponding proteins to 0.23 ± 0.21 (P < 0.01) and 0.46 ± 0.30-fold (P < 0.01) the respective controls without angiotensin II. Angiotensin II also impaired morphological changes associated with early adipogenesis. Hence, we demonstrated that angiotensin II is able to directly reduce adipogenic differentiation of SGBS preadipose cells.

  9. Putative intermediates in the nerve cell differentiation pathway in hydra have properties of multipotent stem cells

    SciTech Connect

    Holstein, T.W.; David, C.N. )

    1990-12-01

    We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are in G1 and have the properties of committed nerve cell precursors. Thus, the interstitial cell population in the peduncle contains both stem cells and noncycling nerve precursors. The presence of stem cells in this region makes it likely that these cells are the immediate targets of signals which give rise to nerve cells.

  10. Evaluation of a Mouse Embryonic Stem Cell Adherent Cell Differentiation and Cytotoxicity (ACDC) assay (SOT)

    EPA Science Inventory

    The Embryonic Stem Cell Test (EST) has been used to evaluate the effects of xenobiotics using three endpoints, stem cell differentiation, stem cell viability and 3T3-cell viability. Our research goal is to establish amodel system that would evaluate chemical effects using a singl...

  11. Hypericum caprifoliatum and Hypericum connatum affect human trophoblast-like cells differentiation and Ca2+ influx

    PubMed Central

    da Conceição, Aline O.; von Poser, Gilsane Lino; Barbeau, Benoit; Lafond, Julie

    2014-01-01

    Objective To study the effect of crude methanol and n-hexane extracts of Hypericum connatum (H. connatum) and Hypericum caprifoliatum on trophoblast-like cells. Methods BeWo and JEG-3 trophoblast-like cells were submitted to different extract concentrations (1, 5, 10 and 15 µg/mL) and evaluated in relation to cell viability and in vitro trophoblast differentiation and function. Cell viability was evaluated using WST-1 reagent. Differentiation was measured by luciferase production, hCG production/release, and mitogen-activated protein kinase signaling pathway activation. The function of the trophoblast-like cells was measured by 45Ca2+ influx evaluation. Results The results showed a decrease in cell viability/proliferation. Both plants and different extracts induced a significant decrease in hCG production/release and luciferase production. H. connatum did not cause mitogen-activated protein kinase signaling pathway disturbance; however, Hypericum caprifoliatum n-hexane extract at 15 µg/mL inhibited extracellular signal-regulated kinase 1/2 activation. The significant increase in Ca2+ influx by JEG-3 cells was seen after short and long incubation times with H. connatum methanolic extract at 15 µg/mL. Conclusions The results indicated that these two Hypericum species extracts can interfere on trophoblast differentiation and Ca2+ influx, according to their molecular diversity. Although in vivo experiments are necessary to establish their action on placental formation and function, this study suggests that attention must be paid to the potential toxic effect of these plants. PMID:25182721

  12. Lectins stain cells differentially in the coral, Montipora capitata

    USGS Publications Warehouse

    Work, Thierry M.; Farah, Yael

    2014-01-01

    A limitation in our understanding of coral disease pathology and cellular pathogenesis is a lack of reagents to characterize coral cells. We evaluated the utility of plant lectins to stain tissues of a dominant coral, Montipora capitata, from Hawaii. Of 22 lectins evaluated, nine of these stained structures in the upper or basal body wall of corals. Specific structures revealed by lectins that were not considered distinct or evident on routine hematoxylin and eosin sections of coral tissues included apical and basal granules in gastrodermis and epidermis, cnidoglandular tract and actinopharynx cell surface membranes, capsules of mature holotrichous isorhizas, and perivitelline and periseminal cells. Plant lectins could prove useful to further our understanding of coral physiology, anatomy, cell biology, and disease pathogenesis.

  13. Programmed cell death in the plant immune system.

    PubMed

    Coll, N S; Epple, P; Dangl, J L

    2011-08-01

    Cell death has a central role in innate immune responses in both plants and animals. Besides sharing striking convergences and similarities in the overall evolutionary organization of their innate immune systems, both plants and animals can respond to infection and pathogen recognition with programmed cell death. The fact that plant and animal pathogens have evolved strategies to subvert specific cell death modalities emphasizes the essential role of cell death during immune responses. The hypersensitive response (HR) cell death in plants displays morphological features, molecular architectures and mechanisms reminiscent of different inflammatory cell death types in animals (pyroptosis and necroptosis). In this review, we describe the molecular pathways leading to cell death during innate immune responses. Additionally, we present recently discovered caspase and caspase-like networks regulating cell death that have revealed fascinating analogies between cell death control across both kingdoms.

  14. Chemo-mechanical control of neural stem cell differentiation

    NASA Astrophysics Data System (ADS)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  15. The maize transcription factor myb-related protein-1 is a key regulator of the differentiation of transfer cells.

    PubMed

    Gómez, Elisa; Royo, Joaquín; Muñiz, Luis M; Sellam, Olivier; Paul, Wyatt; Gerentes, Denise; Barrero, Cristina; López, Maribel; Perez, Pascual; Hueros, Gregorio

    2009-07-01

    Transfer cells are highly modified plant cells specialized in the transport of solutes. They differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. In maize (Zea mays) seeds, transfer cells are located at the base of the endosperm. It is currently unknown how apical-basal polarity is established or why the peripheral cells at the base of the endosperm differentiate into transfer instead of aleurone cells. Here, we show that in epidermal cells committed to develop into aleurone cells, the ectopic expression of the transfer cell-specific transcriptional activator Myb-Related Protein-1 (MRP-1) is sufficient to temporarily transform them into transfer cells. These transformed cells acquire distinct transfer cell features, such as cell wall ingrowths and an elongated shape. In addition, they express a number of MRP-1 target genes presumably involved in defense. We also show that the expression of MRP-1 is needed to maintain the transfer cell phenotype. Later in development, an observed reduction in the ectopic expression of MRP-1 was followed by the reversion of the transformed cells, which then acquire aleurone cell features.

  16. The ability of mouse nuclear transfer embryonic stem cells to differentiate into primordial germ cells.

    PubMed

    Mansouri, Vahid; Salehi, Mohammad; Nourozian, Mohsen; Fadaei, Fatemeh; Farahani, Reza Mastery; Piryaei, Abbas; Delbari, Ali

    2015-05-01

    Nuclear transfer embryonic stem cells (ntESCs) show stem cell characteristics such as pluripotency but cause no immunological disorders. Although ntESCs are able to differentiate into somatic cells, the ability of ntESCs to differentiate into primordial germ cells (PGCs) has not been examined. In this work, we examined the capacity of mouse ntESCs to differentiate into PGCs in vitro. ntESCs aggregated to form embryoid bodies (EB) in EB culture medium supplemented with bone morphogenetic protein 4(BMP4) as the differentiation factor. The expression level of specific PGC genes was compared at days 4 and 8 using real time PCR. Flow cytometry and immunocytochemical staining were used to detect Mvh as a specific PGC marker. ntESCs expressed particular genes related to different stages of PGC development. Flow cytometry and immunocytochemical staining confirmed the presence of Mvh protein in a small number of cells. There were significant differences between cells that differentiated into PGCs in the group treated with Bmp4 compared to non-treated cells. These findings indicate that ntESCs can differentiate into putative PGCs. Improvement of ntESC differentiation into PGCs may be a reliable means of producing mature germ cells.

  17. Species Differentiation of Chinese Mollitrichosiphum (Aphididae: Greenideinae) Driven by Geographical Isolation and Host Plant Acquirement

    PubMed Central

    Zhang, Ruiling; Huang, Xiaolei; Jiang, Liyun; Lei, Fumin; Qiao, Gexia

    2012-01-01

    The impact of both the uplift of the Qinghai-Tibetan Plateau (QTP) and the separation of the Taiwan and Hainan Islands on the evolution of the fauna and flora in adjacent regions has been a topic of considerable interest. Mollitrichosiphum is a polyphagous insect group with a wide range of host plants (14 families) and distributions restricted to Southeast Asia. Based on the mitochondrial Cytochrome C Oxidase Subunit I (COI) and Cytochrome b (Cytb) genes, the nuclear elongation factor-1α (EF-1α) gene, and the detailed distribution and host plant data, we investigated the species differentiation modes of the Chinese Mollitrichosiphum species. Phylogenetic analyses supported the monophyly of Mollitrichosiphum. The divergence time of Mollitrichosiphum tenuicorpus (c. 11.0 mya (million years ago)), Mollitrichosiphum nandii and Mollitrichosiphum montanum (c. 10.6 mya) was within the time frame of the uplift of the QTP. Additionally, basal species mainly fed on Fagaceae, while species that fed on multiple plants diverged considerably later. Ancestral state reconstruction suggests that Fagaceae may be the first acquired host, and the acquisition of new hosts and the expansion of host range may have promoted species differentiation within this genus. Overall, it can be concluded that geographical isolation and the expansion of the host plant range may be the main factors driving species differentiation of Mollitrichosiphum. PMID:22949873

  18. Differentiation of cultured epithelial cells: Response to toxic agents

    SciTech Connect

    Rice, R.H.; LaMontagne, A.D.; Petito, C.T.; Rong, Xianhui )

    1989-03-01

    Cell culture systems are instrumental in elucidating regulation of normal function and mechanisms of its perturbation by toxic substances. To this end, three applications of epithelial cells cultured with 3T3 feeder layer support are described. First, treatment of the premalignant human epidermal keratinocyte line SCC-12F2 with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate suppressed cell growth and differentiation. This agent produced a biphasic growth response greatly inhibiting cell growth at 1 to 10 nM, but much less above 100 nM. Expression of the differentiated functions involucrin and transglutaminase was found to be inhibited markedly at concentrations above 10 nM. Second, 3-methylcholanthrene toxicity was surveyed in a variety of rat epithelial cell types. The two most sensitive to growth inhibition were epidermal and mammary epithelial cells, while those from bladder, prostate, thyroid, and endometrium were insensitive to growth inhibition. Finally, expression of estrogen receptors in rat endometrial cells was shown to be stimulated by the cAmP-elevating agent forskolin. Maximal stimulation of 3- to 6-fold occurred in 6 hr, compatible with a requirement for protein synthesis. Pursuit of such results will aid in understanding differences in response among cell types and species, in elucidating mechanisms of action of known toxic substances and, ultimately, in predicting toxicity of less well understood agents.

  19. Genetic differentiation among Maconellicoccus hirsutus (Hemiptera: Pseudococcidae) populations living on different host plants.

    PubMed

    Rosas-García, Ninfa M; Sarmiento-Benavides, Sandra L; Villegas-Mendoza, Jesús M; Hernández-Delgado, Sanjuana; Mayek-Pérez, Netzahualcoyotl

    2010-06-01

    The pink hibiscus mealybug Maconellicoccus hirsutus (Green) is a dangerous pest that damages a wide variety of agricultural, horticultural, and forestry crops. Amplified fragment length polymorphism (AFLP) fingerprints were used to characterize the genetic variation of 11 M. hirsutus populations infesting three plant species in Nayarit, Mexico. Analysis was carried out using four primers combinations, producing 590 polymorphic bands. Cluster analysis, as well as bootstrap dendrogram and nonmetric multidimensional scaling analysis, grouped M. hirsutus populations according to their host plant. The estimated F(ST) values indicated a high differentiation in M. hirsutus populations among the three host plant species. These results were also supported by a Bayesian analysis, which indicated a population clustering robustness according to their host plant. Genetic variation among populations is not caused by geographic distances, as shown by a Mantel test.

  20. Inhibition of murine erythroleukemia cell differentiation by 3-deazaadenosine.

    PubMed

    Sherman, M L; Shafman, T D; Spriggs, D R; Kufe, D W

    1985-11-01

    Recent studies have demonstrated that 5'-methylthioadenosine, an inhibitor of S-adenosylhomocysteine (AdoHcy) hydrolase, blocks induction of murine erythroleukemia cell (MEL) differentiation. The nucleoside analogue 3-deazaadenosine (c3Ado) is both an efficient substrate and a potent inhibitor of AdoHcy hydrolase. The present study was undertaken to determine whether c3Ado would similarly inhibit MEL differentiation. The results demonstrate that c3Ado inhibits induction of MEL differentiation by dimethyl sulfoxide, hexamethylene bisacetamide, butyric acid, and diazapam. c3Ado blocks the appearance of the differentiated MEL phenotype by inhibiting both MEL heme synthesis and transcription of alpha- and beta-globin RNA. The inhibitory effect of c3Ado on MEL differentiation is concentration dependent, reversible, and potentiated by L-homocysteine thiolactone. Furthermore the AdoHcy/AdoMet ratio increases nearly 3.5-fold after 24 h of treatment with 50 microM c3Ado. In contrast, this c3Ado effect is not associated with polyamine depletion or cytostasis. These findings indicate that c3Ado blocks the induction of MEL differentiation at a transcriptional level and that this effect may be related to inhibition of AdoHcy hydrolase.

  1. PU.1 silencing leads to terminal differentiation of erythroleukemia cells

    SciTech Connect

    Atar, Orna; Levi, Ben-Zion . E-mail: blevi@technion.ac.il

    2005-04-22

    The transcription factor PU.1 plays a central role in development and differentiation of hematopoietic cells. Evidence from PU.1 knockout mice indicates a pivotal role for PU.1 in myeloid lineage and B-lymphocyte development. In addition, PU.1 is a key player in the development of Friend erythroleukemia disease, which is characterized by proliferation and differentiation arrest of proerythrocytes. To study the role of PU.1 in erythroleukemia, we have used murine erythroleukemia cells, isolated from Friend virus-infected mice. Expression of PU.1 small interfering RNA in these cells led to significant inhibition of PU.1 levels. This was accompanied by inhibition of proliferation and restoration in the ability of the proerythroblastic cells to produce hemoglobin, i.e., reversion of the leukemic phenotype. The data suggest that overexpression of PU.1 gene is the immediate cause for maintaining the leukemic phenotype of the disease by retaining the self-renewal capacity of transformed erythroblastic cells and by blocking the terminal differentiation program towards erythrocytes.

  2. Proton-dependent coniferin transport, a common major transport event in differentiating xylem tissue of woody plants.

    PubMed

    Tsuyama, Taku; Kawai, Ryo; Shitan, Nobukazu; Matoh, Toru; Sugiyama, Junji; Yoshinaga, Arata; Takabe, Keiji; Fujita, Minoru; Yazaki, Kazufumi

    2013-06-01

    Lignin biosynthesis is an essential physiological activity of vascular plants if they are to survive under various environmental stresses on land. The biosynthesis of lignin proceeds in the cell wall by polymerization of precursors; the initial step of lignin polymerization is the transportation of lignin monomers from the cytosol to the cell wall, which is critical for lignin formation. There has been much debate on the transported form of the lignin precursor, either as free monolignols or their glucosides. In this study, we performed biochemical analyses to characterize the membrane transport mechanism of lignin precursors using angiosperms, hybrid poplar (Populus sieboldii × Populus grandidentata) and poplar (Populus sieboldii), as well gymnosperms, Japanese cypress (Chamaecyparis obtusa) and pine (Pinus densiflora). Membrane vesicles prepared from differentiating xylem tissues showed clear ATP-dependent transport activity of coniferin, whereas less than 4% of the coniferin transport activity was seen for coniferyl alcohol. Bafilomycin A1 and proton gradient erasers markedly inhibited coniferin transport in hybrid poplar membrane vesicles; in contrast, vanadate had no effect. Cis-inhibition experiments suggested that this transport activity was specific for coniferin. Membrane fractionation of hybrid poplar microsomes demonstrated that transport activity was localized to the tonoplast- and endomembrane-rich fraction. Differentiating xylem of Japanese cypress exhibited almost identical transport properties, suggesting the involvement of a common endomembrane-associated proton/coniferin antiport mechanism in the lignifying tissues of woody plants, both angiosperms and gymnosperms.

  3. Microenvironmental changes during differentiation of mesenchymal stem cells towards chondrocytes

    PubMed Central

    Djouad, Farida; Delorme, Bruno; Maurice, Marielle; Bony, Claire; Apparailly, Florence; Louis-Plence, Pascale; Canovas, François; Charbord, Pierre; Noël, Danièle; Jorgensen, Christian

    2007-01-01

    Chondrogenesis is a process involving stem-cell differentiation through the coordinated effects of growth/differentiation factors and extracellular matrix (ECM) components. Recently, mesenchymal stem cells (MSCs) were found within the cartilage, which constitutes a specific niche composed of ECM proteins with unique features. Therefore, we hypothesized that the induction of MSC differentiation towards chondrocytes might be induced and/or influenced by molecules from the microenvironment. Using microarray analysis, we previously identified genes that are regulated during MSC differentiation towards chondrocytes. In this study, we wanted to precisely assess the differential expression of genes associated with the microenvironment using a large-scale real-time PCR assay, according to the simultaneous detection of up to 384 mRNAs in one sample. Chondrogenesis of bone-marrow-derived human MSCs was induced by culture in micropellet for various periods of time. Total RNA was extracted and submitted to quantitative RT-PCR. We identified molecules already known to be involved in attachment and cell migration, including syndecans, glypicans, gelsolin, decorin, fibronectin, and type II, IX and XI collagens. Importantly, we detected the expression of molecules that were not previously associated with MSCs or chondrocytes, namely metalloproteases (MMP-7 and MMP-28), molecules of the connective tissue growth factor (CTGF); cef10/cyr61 and nov (CCN) family (CCN3 and CCN4), chemokines and their receptors chemokine CXC motif ligand (CXCL1), Fms-related tyrosine kinase 3 ligand (FlT3L), chemokine CC motif receptor (CCR3 and CCR4), molecules with A Disintegrin And Metalloproteinase domain (ADAM8, ADAM9, ADAM19, ADAM23, A Disintegrin And Metalloproteinase with thrombospondin type 1 motif ADAMTS-4 and ADAMTS-5), cadherins (4 and 13) and integrins (α4, α7 and β5). Our data suggest that crosstalk between ECM components of the microenvironment and MSCs within the cartilage is

  4. FTIR Spectroscopic and Molecular Analysis during Differentiation of Pluripotent Stem Cells to Pancreatic Cells

    PubMed Central

    Mata-Miranda, Monica Maribel; Sanchez-Monroy, Virginia; Delgado-Macuil, Raul Jacobo; Perez-Ishiwara, David Guillermo

    2016-01-01

    Some of the greatest challenges in stem cells (SCs) biology and regenerative medicine are differentiation control of SCs and ensuring the purity of differentiated cells. In this work, we differentiated mouse pluripotent stem cells (mPSCs) toward pancreatic cells characterizing this differentiation process by molecular and spectroscopic technics. Both mPSCs and Differentiated Pancreatic Cells (DPCs) were subjected to a genetic, phenotypic, and biochemical analysis by real-time quantitative PCR (RT-qPCR), immunocytochemistry, and Fourier Transform Infrared (FTIR) spectroscopy. Cultured mPCSs expressed pluripotent genes and proteins (Nanog and SOX2). DPCs expressed endodermal genes (SOX17 and Pdx1) at day 11, an inductor gene of embryonic pancreas development (Pdx1) at day 17 and pancreas genes and proteins (Insulin and Glucagon) at day 21 of differentiation. Likewise, FTIR spectra of mPSCs and DPCs at different maturation stages (11, 17, and 21 days) were obtained and showed absorption bands related with different types of biomolecules. These FTIR spectra exhibited significant spectral changes agreeing with the differentiation process, particularly in proteins and nucleic acids bands. In conclusion, the obtained DPCs passed through the chronological stages of embryonic pancreas development and FTIR spectra provide a new biophysical parameter based on molecular markers indicating the differentiation process of mPSCs to specialized cells. PMID:27651798

  5. FTIR Spectroscopic and Molecular Analysis during Differentiation of Pluripotent Stem Cells to Pancreatic Cells.

    PubMed

    Vazquez-Zapien, Gustavo Jesus; Mata-Miranda, Monica Maribel; Sanchez-Monroy, Virginia; Delgado-Macuil, Raul Jacobo; Perez-Ishiwara, David Guillermo; Rojas-Lopez, Marlon

    2016-01-01

    Some of the greatest challenges in stem cells (SCs) biology and regenerative medicine are differentiation control of SCs and ensuring the purity of differentiated cells. In this work, we differentiated mouse pluripotent stem cells (mPSCs) toward pancreatic cells characterizing this differentiation process by molecular and spectroscopic technics. Both mPSCs and Differentiated Pancreatic Cells (DPCs) were subjected to a genetic, phenotypic, and biochemical analysis by real-time quantitative PCR (RT-qPCR), immunocytochemistry, and Fourier Transform Infrared (FTIR) spectroscopy. Cultured mPCSs expressed pluripotent genes and proteins (Nanog and SOX2). DPCs expressed endodermal genes (SOX17 and Pdx1) at day 11, an inductor gene of embryonic pancreas development (Pdx1) at day 17 and pancreas genes and proteins (Insulin and Glucagon) at day 21 of differentiation. Likewise, FTIR spectra of mPSCs and DPCs at different maturation stages (11, 17, and 21 days) were obtained and showed absorption bands related with different types of biomolecules. These FTIR spectra exhibited significant spectral changes agreeing with the differentiation process, particularly in proteins and nucleic acids bands. In conclusion, the obtained DPCs passed through the chronological stages of embryonic pancreas development and FTIR spectra provide a new biophysical parameter based on molecular markers indicating the differentiation process of mPSCs to specialized cells.

  6. Generating pluripotent stem cells: Differential epigenetic changes during cellular reprogramming

    PubMed Central

    Tobin, Stacey C.; Kim, Kitai

    2013-01-01

    Pluripotent stem cells hold enomous potential for therapuetic applications in tissue replacement therapy. Reprogramming somatic cells from a patient donor to generate pluripotent stem cells involves both ethical concerns inherent in the use of embryonic and oocyte-derived stem cells, as well as issues of histocompatibility. Among the various pluripotent stem cells, induced pluripotent stem cells (iPSC)—derived by ectopic expression of four reprogramming factors in donor somatic cells—are superior in terms of ethical use, histocompatibility, and derivation method. However, iPSC also show genetic and epigenetic differences that limit their differentiation potential, functionality, safety, and potential clinical utility. Here, we discuss the unique characteristics of iPSC and approaches that are being taken to overcome these limitations. PMID:22819821

  7. Differentiation and Genomic Instability in a Human Mammary Cell Model

    NASA Technical Reports Server (NTRS)

    Richmond, R.; Kale, R.; Pettengill, O.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Harvest of prophylactic mastectomy specimens from an obligate heterozygote for ataxia-telangiectasia provided autologous fibroblasts as well epithelial cells (HMEC). The routine availability of these autologous cells has provided an opportunity to study cell-cell interactions in coculture and monoculture, and in 3-dimensional cultures grown in the NASA rotating bioreactor. HMEC and stromal fibroblasts grown in 2-dimensional monoculture were both observed to produce extracellular matrix. Similar matrix was encountered in 3-dimensional cultures containing HMEC. Metaphases were analyzed. For stromal fibroblasts, genomic aberrations were found in 18% of metaphase spreads. For HMEC, aberrations were greater such that a majority were found to be abnormal. The level of genomic instability determined for these noncancerous cells in 2-dimensional monoculture should be useful for generating a human cell model that can correlate the effects of differentiation in 3-dimensional coculture on the level of genomic instability.

  8. Differentiation of HL60 cells: involvement of protein phosphorylation

    SciTech Connect

    Spearman, T.N.; Fontana, J.A.; Butcher, F.R.; Durham, J.P.

    1986-05-01

    The addition of retinoic acid (RA) to the human promyelocytic leukemic cell line HL60 in culture results in the cessation of growth and the acquisition of a more mature phenotype. Previous work in these laboratories has demonstrated a concomitant increase in the activity of calcium-dependent, phospholipid-sensitive protein kinase (PK-C). HL60 cells were incubated with /sup 32/P-P/sub i/ in the absence and presence of RA, homogenized, and aliquots subjected to two-dimensional electrophoresis. A comparison of autoradiograms made from these gels revealed several phosphoproteins whose radiolabeling was affected by RA. The radiolabeling of one particular phosphoprotein (49kd, pI 4.8) was found to be increased prior to phenotypic evidence of differentiation. It was demonstrated via incubating HL60 cytosol with /sup 32/P -ATP and Ca/sup 2 +/ in the absence and presence of phosphatidylserine and resolving the labeled proteins as above that this protein is phosphorylated by PK-C. The labeling of this protein was also increased by RA in other leukemic cell lines which showed phenotypic evidence of differentiation while no effect was seen in HL60 sublines resistant to RA or in mature neutrophils (the end product of myeloid differentiation). These results suggest that this protein may be an important intermediate in myeloid differentiation.

  9. ENERGY PRODUCTION AND POLLUTION PREVENTION AT SEWAGE TREATMENT PLANTS USING FUEL CELL POWER PLANTS

    EPA Science Inventory

    The paper discusses energy production and pollution prevention at sewage treatment plants using fuel cell power plants. Anaerobic digester gas (ADG) is produced at waste water treatment plants during the anaerobic treatment of sewage to reduce solids. The major constituents are...

  10. Adipogenic differentiation of mesenchymal stem cells on micropatterned polyelectrolyte surfaces.

    PubMed

    Kawazoe, Naoki; Guo, Likun; Wozniak, Michal J; Imaizumi, Yumie; Tateishi, Tetsuya; Zhang, Xingdong; Chen, Guoping

    2009-01-01

    Three kinds of photoreactive polyelectrolytes of polyallylamine (PAAm), poly(acrylic acid) (PAAc), and poly(vinyl alcohol) (PVA) were synthesized by the introduction of azidophenyl groups in the respective polymers. The photoreactive PAAm, PAAc, and PVA were micropatterned on polystyrene surfaces by photolithography. Observation with optical microscopy and scanning probe microscopy demonstrated the formation of a striped pattern of polyelectrolytes with a width of 200 microm. The micropatterned polyelectrolytes swelled in water. The micropatterned surfaces were used for cell culture of mesenchymal stem cells (MSCs) and their effects on adipogenic differentiation were investigated. The MSCs adhered to and proliferated evenly on the PAAm- and PAAc-patterned surfaces while they formed a cell pattern on the PVA-patterned surface. The PAAm-, PAAc-grafted, and polystyrene surfaces supported cell adhesion while the PVA-grafted surface did not. When cultured in adipogenic differentiation medium, the adipogenic differentiation of MSCs on the polyelectrolyte-patterned surfaces was demonstrated by the formation of lipid vacuoles and gene expression analysis. Oil Red-O-positive cells showed an even distribution on the PAAm- and PAAc-patterned surfaces, while they showed a pattern on the PVA-patterned surface. The fraction of Oil RedO-positive cells increased with culture time. The MSCs cultured on the PAAm-, PAAc-grafted, and polystyrene surfaces in adipogenic differentiation medium expressed the adipogenesis marker genes of peroxisome proliferator-activated receptor gamma2 (PPARgamma2), lipoprotein lipase (LPL), and fatty acid binding protein 4 (FABP4). These results indicate that the PAAm-, and PAAc-grafted, and polystyrene surfaces supported the adipogenesis of MSCs while a PVA-grafted surface did not.

  11. Asymmetric cell divisions in flowering plants - one mother, "two-many" daughters.

    PubMed

    Ranganath, R M

    2005-09-01

    Plant development shows a fascinating range of asymmetric cell divisions. Over the years, however, cellular differentiation has been interpreted mostly in terms of a mother cell dividing mitotically to produce two daughter cells of different fates. This popular view has masked the significance of an entirely different cell fate specification pathway, where the mother cell first becomes a coenocyte and then cellularizes to simultaneously produce more than two specialized daughter cells. The "one mother - two different daughters" pathways rely on spindle-assisted mechanisms, such as translocation of the nucleus/spindle to a specific cellular site and orientation of the spindle, which are coordinated with cell-specific allocation of cell fate determinants and cytokinesis. By contrast, during "coenocyte-cellularization" pathways, the spindle-assisted mechanisms are irrelevant since cell fate specification emerges only after the nuclear divisions are complete, and the number of specialized daughter cells produced depends on the developmental context. The key events, such as the formation of a coenocyte and migration of the nuclei to specific cellular locations, are coordinated with cellularization by unique types of cell wall formation. Both one mother - two different daughters and the coenocyte-cellularization pathways are used by higher plants in precise spatial and time windows during development. In both the pathways, epigenetic regulation of gene expression is crucial not only for cell fate specification but also for its maintenance through cell lineage. In this review, the focus is on the coenocyte-cellularization pathways in the context of our current understanding of the asymmetric cell divisions. Instances where cell differentiation does not involve an asymmetric division are also discussed to provide a comprehensive account of cell differentiation.

  12. Differentiation state affects morphine induced cell regulation in neuroblastoma cultured cells.

    PubMed

    Fiore, Giovina; Ghelardini, Carla; Bruni, Giancarlo; Guarna, Massimo; Bianchi, Enrica

    2013-10-25

    Neuroblastoma (NB) is the most common extracranial solid cancer in childhood and the most common cancer in infancy. Our purpose was to investigate in vitro how cancer cell survival occurs in presence of morphine in undifferentiated and differentiated SHSY-5Y human neuroblastoma cultured cell line. Exposure of differentiated cells to morphine dose-dependently induced apoptosis in these cells through c-Jun N-terminal kinase (JNK)/caspase pathway. Otherwise, morphine induced activation for mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway, caused positive regulation of cell survival in undifferentiated cells. Therefore, cell differentiation state bimodally affects the cellular regulation activity triggered by morphine in isolated cultured neuroblastoma cells raising concerns about the application of morphine to this type of cancer patients.