38 research outputs found

    Selection and Validation of Reference Genes for Quantitative Real-Time PCR in Buckwheat (Fagopyrum esculentum) Based on Transcriptome Sequence Data

    Get PDF
    Quantitative reverse transcription PCR (qRT-PCR) is one of the most precise and widely used methods of gene expression analysis. A necessary prerequisite of exact and reliable data is the accurate choice of reference genes. We studied the expression stability of potential reference genes in common buckwheat (Fagopyrum esculentum) in order to find the optimal reference for gene expression analysis in this economically important crop. Recently sequenced buckwheat floral transcriptome was used as source of sequence information. Expression stability of eight candidate reference genes was assessed in different plant structures (leaves and inflorescences at two stages of development and fruits). These genes are the orthologs of Arabidopsis genes identified as stable in a genome-wide survey gene of expression stability and a traditionally used housekeeping gene GAPDH. Three software applications – geNorm, NormFinder and BestKeeper - were used to estimate expression stability and provided congruent results. The orthologs of AT4G33380 (expressed protein of unknown function, Expressed1), AT2G28390 (SAND family protein, SAND) and AT5G46630 (clathrin adapter complex subunit family protein, CACS) are revealed as the most stable. We recommend using the combination of Expressed1, SAND and CACS for the normalization of gene expression data in studies on buckwheat using qRT-PCR. These genes are listed among five the most stably expressed in Arabidopsis that emphasizes utility of the studies on model plants as a framework for other species

    Photosynthesis-dependent H₂O₂ transfer from chloroplasts to nuclei provides a high-light signalling mechanism

    Get PDF
    Chloroplasts communicate information by signalling to nuclei during acclimation to fluctuating light. Several potential operating signals originating from chloroplasts have been proposed, but none have been shown to move to nuclei to modulate gene expression. One proposed signal is hydrogen peroxide (H2O2) produced by chloroplasts in a light-dependent manner. Using HyPer2, a genetically encoded fluorescent H2O2 sensor, we show that in photosynthetic Nicotiana benthamiana epidermal cells, exposure to high light increases H2O2 production in chloroplast stroma, cytosol and nuclei. Critically, over-expression of stromal ascorbate peroxidase (H2O2 scavenger) or treatment with DCMU (photosynthesis inhibitor) attenuates nuclear H2O2 accumulation and high light-responsive gene expression. Cytosolic ascorbate peroxidase over-expression has little effect on nuclear H2O2 accumulation and high light-responsive gene expression. This is because the H2O2 derives from a sub-population of chloroplasts closely associated with nuclei. Therefore, direct H2O2 transfer from chloroplasts to nuclei, avoiding the cytosol, enables photosynthetic control over gene expression

    Predictors of Visceral Leishmaniasis Relapse in HIV-Infected Patients: A Systematic Review

    Get PDF
    Visceral leishmaniasis (VL) is the most serious form of an insect-transmitted parasitic disease prevalent in 70 countries. The disease is caused by species of the L. donovani complex found in different geographical regions. These parasites have substantially different clinical, drug susceptibility and epidemiological characteristics. According to data from the World Health Organization, the areas where HIV-Leishmania co-infection is distributed are extensive. HIV infection increases the risk of developing VL, reduces the likelihood of a therapeutic response, and greatly increases the probability of relapse. A better understanding of the factors promoting relapses is essential; therefore we performed a systematic review of articles involving all articles assessing the predictors of VL relapse in HIV-infected individuals older than 14 years of age. Out of 178 relevant articles, 18 met the inclusion criteria and in total, data from 1017 patients were analyzed. We identified previous episodes of VL relapse, CD4+ lymphocyte count fewer than 100 cells/mL at VL diagnosis, and the absence of an increase in CD4+ counts at follow-up as major factors associated with VL relapse. Knowledge of relapse predictors can help to identify patients with different degrees of risk, facilitate and direct prophylaxis choices, and aid in patient counseling

    Transcriptomic Analysis of the Salivary Glands of an Invasive Whitefly

    Get PDF
    <div><h3>Background</h3><p>Some species of the whitefly <em>Bemisia tabaci</em> complex cause tremendous losses to crops worldwide through feeding directly and virus transmission indirectly. The primary salivary glands of whiteflies are critical for their feeding and virus transmission. However, partly due to their tiny size, research on whitefly salivary glands is limited and our knowledge on these glands is scarce.</p> <h3>Methodology/Principal Findings</h3><p>We sequenced the transcriptome of the primary salivary glands of the Mediterranean species of <em>B. tabaci</em> complex using an effective cDNA amplification method in combination with short read sequencing (Illumina). In a single run, we obtained 13,615 unigenes. The quantity of the unigenes obtained from the salivary glands of the whitefly is at least four folds of the salivary gland genes from other plant-sucking insects. To reveal the functions of the primary glands, sequence similarity search and comparisons with the whole transcriptome of the whitefly were performed. The results demonstrated that the genes related to metabolism and transport were significantly enriched in the primary salivary glands. Furthermore, we found that a number of highly expressed genes in the salivary glands might be involved in secretory protein processing, secretion and virus transmission. To identify potential proteins of whitefly saliva, the translated unigenes were put into secretory protein prediction. Finally, 295 genes were predicted to encode secretory proteins and some of them might play important roles in whitefly feeding.</p> <h3>Conclusions/Significance:</h3><p>The combined method of cDNA amplification, Illumina sequencing and <em>de novo</em> assembly is suitable for transcriptomic analysis of tiny organs in insects. Through analysis of the transcriptome, genomic features of the primary salivary glands were dissected and biologically important proteins, especially secreted proteins, were predicted. Our findings provide substantial sequence information for the primary salivary glands of whiteflies and will be the basis for future studies on whitefly-plant interactions and virus transmission.</p> </div

    International entrepreneurship in SMEs: a study of influencing factors in the textile industry

    Full text link
    The final publication is available at Springer via http://dx.doi.org/10.1007/s11365-012-0242-3International entrepreneurship is an incipient research area with a rapidly increasing body of knowledge and contributions. An important part of this literature has focused on the analysis of the contributing factors to IE development. From these studies, this work attempts to analyse and validate through an integrative model the effect on this construct in SME of some of the main factors proposed by the literature such as Skills and Competences, Attitude and Proactiveness, Creativity and Innovation, Networking, Employees and Activity. To proceed with this aim, we conducted an empirical research focused on 174 textile SME in Spain. The results obtained confirm a positive relationship between the studied factors and the IE development. In consequence, this work agrees with previous literature that point out the need to use multi-theoretical perspectives, combining multiple factors.Gil Pechuán, I.; Expósito Langa, M.; Tomas Miquel, JV. (2013). International entrepreneurship in SMEs: a study of influencing factors in the textile industry. International Entrepreneurship and Management Journal. 9(1):45-57. doi:10.1007/s11365-012-0242-3S455791Akgün, A., Keskin, H., & Byrne, J. (2012). Organizational emotional memory. Management Decision, 50(1), 95–114.Andersén, J. (2011). Strategic resources and firm performance. Management Decision, 49(1), 87–98.Anderson, A. R., Dodd, S. D., & Jack, S. L. (2012). Entrepreneurship as connecting: some implications for theorising and practice. Management Decision, 50(5), 958–971.Appelbaum, S. H., Roy, M., & Gilliland, T. (2011). Globalization of performance appraisals: theory and applications. Management Decision, 49(4), 570–585.Arribas, I., Hernández, P., Urbano, A., & Vila, J. E. (2012). Are social and entrepreneurial attitudes compatible? A behavioral and self-perceptional analysis. Management Decision, 50(10), 1739–1757.Audretsch, D. (2012). Entrepreneurship research. Management Decision, 50(5), 755–764.Autio, E., Sapienza, H. J., & Almeida, J. G. (2000). Effects of age at entry, knowledge intensity, and imitability on international growth. Academy of Management Journal, 43, 909–924.Bannon, L. (1998). Mattel plans to double sales abroad. Wall Street Journal, February 11, (A3 and A8).Battistella, C., Biotto, G., & De Toni, A. (2012). From design driven innovation to meaning strategy. Management Decision, 50(4), 718–743.Bell, J., McNaughton, J., Young, R., & Crick, D. (2003). Towards an integrative model of small firm internationalization. Journal of International Entrepreneurship, 1, 339–362.Bonzo, P., Valadares de Oliveira, P., & McCormarck. (2012). Planning, capabilities, and performance: an integrated value approach. Management Decision, 50(6), 1001–1021.Bossak, J., & Nagashima, S. (1997). Corporate strategies for a borderless world: sharpening your competitive edge. Tokyo: Asian Productivity Organization.Cambra-Fierro, J., Florin, J., Perez, L., & Whitelock, J. (2011). Inter-firm market orientation as antecedent of knowledge transfer, innovation and value creation in networks. Management Decision, 49(3), 444–467.Cantarello, S., Nosella, A., Petroni, G., & Venturini, K. (2011). External technology sourcing: evidence from design-driven innovation. Management Decision, 49(6), 962–983.Chang, Y. Y., Hughes, M., & Hotho, S. (2011). Internal and external antecedents of SMEs’ innovation ambidexterity outcomes. Management Decision, 49(10), 1658–1676.Chaston, I., & Scott, G. J. (2012). Entrepreneurship and open innovation in an emerging economy. Management Decision, 50(7), 1161–1177.Coviello, N. E., & Jones, M. V. (2004). Methodological issues in international entrepreneurship research. Journal of Business Venturing, 19, 485–508.Coviello, N. E., & McAuley, A. (1999). Internationalization and the smaller firm: a review of contemporary empirical research. Management International Review, 39, 223–256.Covin, J., & Slevin, D. (1989). Strategic management of small firms in hostile and benign environments. Strategic Management Journal, 10(1), 75–87.Covin, J., & Slevin, D. (1991). A conceptual model of entrepreneurship as firm behavior. Entrepreneurship Theory and Practice, 16, 7–25.Davis, D., Morris, M., & Allen, J. (1991). Perceived environmental turbulence and its effect on selected entrepreneurship, marketing, and organizational characteristics in industrial firms. Journal of the Academy of Marketing Science, 19(1), 43–51.Dean, C. C., Thibodeaux, M. S., Beyerlein, M., Ebrahimi, B., & Molina, D. (1993). Corporate entrepreneurship and competitive aggressiveness. A comparison of U.S. firms operating in eastern Europe and the Commonwealth of Independent States with U.S. firms in other high-risk environments. Advances in International Comparative Management, 8, 31–54.Dess, G. G., & Robinson, R. B. (1984). Measuring organizational performance in the absence of objective measures: the case of privately held firms and conglomerate business units. Strategic Management Journal, 5, 265–273.Dess, G. G., Lumpkin, G. T., & Covin, J. G. (1997). Entrepreneurial strategy making and firm performance: tests of contingency and configurational models. Strategic Management Journal, 18, 677–695.Díaz-Casero, J. C., Díaz-Aunión, A., Sánchez-Escobedo, M. C., Coduras-Martinez, A., & Hernández-Mogollón, R. (2012). Economic freedom and entrepreneurial activity. Management Decision, 50(9), 1686–1711.Dimitratos, P., & Plakoyiannaki, E. (2003). Theoretical foundations of an international entrepreneurial culture. Journal of International Entrepreneurship, 1, 187–215.Dubini, P., & Aldrich, H. (1991). Personal and extended networks are central to the entrepreneurial process. Journal of Business Venturing, 6, 305–313.Felício, J. A., Rodrigues, R., & Caldeirinha, V. R. (2012). The effect of intrapreneurship on corporate performance. Management Decision, 50(10), 1717–1738.Goktan, A. B., & Miles, G. (2011). Innovation speed and radicalness: are they inversely related? Management Decision, 49(4), 533–547.Gómez-Haro, S., Aragón-Correa, J. A., & Cordón-Pozo, E. (2011). Differentiating the effects of the institutional environment on corporate entrepreneurship. Management Decision, 49(10), 1677–1693.Hitt, M. A., Ireland, R. D., Camp, S. M., & Sexton, L. D. (2001). Strategic entrepreneurship: entrepreneurial strategies for wealth creation [Special Issue]. Strategic Management Journal, 22(6), 479–492.Hotho, S., & Champion, K. (2011). Small businesses in the new creative industries: innovation as a people management challenge. Management Decision, 49(1), 29–54.Hu, Y.-S. (1995). The international transferability of competitive advantage. California Management Review, 37(4), 73–88.Huarng, K. H., & Yu, T. H. K. (2011). Entrepreneurship, process innovation and value creation by a non-profit SME. Management Decision, 49(2), 284–296.Jones, M. V. (1999). The internationalization of small UK high technology based firms. Journal of International Marketing, 7, 15–41.Jones, M. V., & Coviello, N. E. (2005). Internationalization: conceptualising and entrepreneurial process of behaviour in time. Journal of International Business Studies, 36(3):284–303.Khandwalla, P. (1977). The design of organizations. New York: Harcourt Brace Jovanovich.Knight, G. A., & Cavusgil, S. T. (2004). Innovation, organization capabilities, and the born-global firm. Journal of International Business Studies, 35, 124–141.Kropp, F., Lindsay, N. J., & Shoham, A. (2006). Entrepreneurial, market, and learning orientations and international entrepreneurial business venture performance in South African firms. International Marketing Review, 23(5), 504–523.Liebeskind, J. P. (1996). Knowledge, strategy, and the theory of the firm. Strategic Management Journal, 17, 93–107.Lumpkin, G. T., & Dess, G. G. (1996). Clarifying the entrepreneurial construct and linking it to performance. Academy of Management Review, 21, 135–172.McDougall, P. P., & Oviatt, B. M. (2000). International entrepreneurship: the intersection of two research paths. Academy of Management Journal, 43, 902–908.McDougall, P. P., Shane, S., & Oviatt, B. M. (1994). Explaining the formation of international new ventures: the limits of theories from international business research. Journal of Business Venturing, 9, 469–487.McGrath, R. G., MacMillan, I. C., & Venkataraman, S. (1995). Global dimensions of new competencies. In S. Birley & I. C. MacMillan (Eds.), International entrepreneurship. New York: Routledge.McNaughton, R. B. (2001). The export mode decision-making process in small knowledge- intensive firms. Market Intelligence and Planning, 19, 12–20.McNaughton, R. B. (2003). The number of export markets that a firm serves: process models versus the born-global phenomenon. Journal of International Entrepreneurship, 1, 297–311.Miles, R. E., & Snow, C. C. (1978). Organizational strategy, structure and process. New York: McGraw-Hill.Miller, D. (1983). The correlates of entrepreneurship in three types of firms. Management Science, 29(7), 770–791.Miller, D., & Friesen, P. (1984). Organizations: a quantum view. Englewood Cliffs: Prentice-Hall.Morrow, J. F. (1988). International entrepreneurship: a new growth opportunity. New Management, 3, 59–61.Murphy, G. B., Trailer, J. W., & Hill, R. C. (1996). Measuring performance in entrepreneurship research. Journal of Business Research, 36, 15–23.Naman, J. L., & Slevin, D. P. (1993). Entrepreneurship and the concept of fit: a model and empirical tests. Strategic Management Journal, 14, 137–153.Naranjo-Valencia, J. C., Jiménez-Jiménez, D., & Sanz-Valle, R. (2011). Innovation or imitation? The role of organizational culture. Management Decision, 49(1), 55–72.Oviatt, B. M., & McDougall, P. P. (1994). Toward a theory of international new ventures. Journal of International Business Studies, 25(1), 45–64.Oviatt, B. M., & McDougall, P. P. (1999). A framework for understanding accelerated international entrepreneurship. In R. Wright (Ed.), Research in global strategic management (pp. 23–40). Stamford: JAI Press.Oviatt, B. M., & McDougall, P. P. (2005). Defining international entrepreneurship and modeling the speed of internalization. Entrepreneurship Theory & Practice, 29(5), 537–554.Peiris, I.K., Akoorie, M.E.M., & Sinha, P.N. (2012). International entrepreneurship: A critical analysis of studies in the past two decades and future directions for research. Journal of International Entrepreneurship. Article in press.Pinchot, G., III. (1985). Intrapreneuring: why you don’t have to leave the corporation to become entrepreneur. New York: Harper and Row Publishers.Porter, M. (1990). The competitive advantage of nations. London: Collier-Macmillan.Renko, M., Shrader, R. C., & Simon, M. (2012). Perception of entrepreneurial opportunity: a general framework. Management Decision, 50(7), 1233–1251.Sandulli, F. D., Fernandez-Menendez, J., Rodriguez-Duarte, A., & Lopez-Sanchez, J. I. (2012). Testing the Schumpeterian hypotheses on an open innovation framework. Management Decision, 50(7), 1222–1232.Santos, F. J., Romero, I., & Fernández-Serrano, J. (2012). SMEs and entrepreneurial quality from a macroeconomic perspective. Management Decision, 50(8), 1382–1395.Shama, A. (1995). Entry strategies of U.S. firms to the former Soviet Bloc and Eastern Europe. California Management Review, 37(3), 90–109.Simon, H. (1996). Hidden champions: lessons from 500 of the world’s best unknown companies. Boston: Harvard Business School Press.Singh, S., Darwish, T. K., Costa, A. C., & Anderson, N. (2012). Measuring HRM and organisational performance: concepts, issues, and framework. Management Decision, 50(4), 651–667.Smart, T. (1996). GE’s Welch: ‘Fighting like hell to be No. 1’. Business Week, July 8, 48.Snow, C., & Hrebiniak, L. (1980). Strategy, distinctive competence, and organizational performance. Administrative Science Quarterly, 25, 317–336.Stevenson, H. H., & Jarillo, J. C. (1990). A paradigm of entrepreneurship: entrepreneurial management. Strategic Management Journal, 11, 17–27.Styles, C., & Seymour, R. G. (2006). Opportunities for marketing researchers in international entrepreneurship. International Marketing Review, 23(2), 126–145.Turner, R., Ledwith, A., & Kelly, J. (2012). Project management in small to medium-sized enterprises: tailoring the practices to the size of company. Management Decision, 50(5), 942–957.Venkatraman, N., & Ramanujam, V. (1986). Measurement of business performance in strategy research: a comparison of approaches. Academy of Management Review, 11, 801–814.Vlasic, B. (1998). The little car that could carry Chrysler overseas. Business Week, 19, 39.Welbourne, T. M., Neck, H., & Meyer, G. D. (2012). The entrepreneurial growth ceiling: using people and innovation to mitigate risk and break through the growth ceiling in initial public offerings. Management Decision, 50(5), 778–796.Williamson, P. J. (1997). Asia’s new competitive game. Harvard Business Review, 75(5), 55–67.Yeoh, P. L. (2004). International learning: antecedents and performance implications among newly internationalizing companies in an exporting context. International Marketing Review, 21(4/5), 511–535.Zahra, S. A. (1991). Predictors and financial outcomes of corporate entrepreneurship. An exploratory study. Journal of Business Venturing, 6(4), 259–285.Zahra, S. A. (1993a). Environment, corporate entrepreneurship and financial performance. A taxonomic approach. Journal of Business Venturing, 8(4), 319–340.Zahra, S. A. (1993b). A conceptual model of entrepreneurship as firm behavior: a critique and extensión. Entrepreneurship Theory and Practice, 17(4), 5–21.Zahra, S. A., & George, G. (2002). International entrepreneurship: the current status of the field and future agenda. In M. A. Hitt, R. D. Ireland, S. M. Camp, & D. L. Sexton (Eds.), Strategic entrepreneurship: creating a new mindset. Oxford: Blackwell Publishers.Zahra, S. A., Jennings, D. F., & Kuratko, D. F. (1999). The antecedents and consequences of firm-level entrepreneurship: the state of the field. Entrepreneurship Theory and Practice, 24(2), 45–63.Zhou, L. (2007). The effects of entrepreneurial proclivity and foreign market knowledge on early internationalization. Journal of World Business, 42(3), 281–293

    Current status of the multinational Arabidopsis community

    Get PDF
    The multinational Arabidopsis research community is highly collaborative and over the past thirty years these activities have been documented by the Multinational Arabidopsis Steering Committee (MASC). Here, we (a) highlight recent research advances made with the reference plant Arabidopsis thaliana; (b) provide summaries from recent reports submitted by MASC subcommittees, projects and resources associated with MASC and from MASC country representatives; and (c) initiate a call for ideas and foci for the “fourth decadal roadmap,” which will advise and coordinate the global activities of the Arabidopsis research community

    Phenotypes Determined by Cluster Analysis and Their Survival in the Prospective European Scleroderma Trials and Research Cohort of Patients With Systemic Sclerosis

    Get PDF
    Objective: Systemic sclerosis (SSc) is a heterogeneous connective tissue disease that is typically subdivided into limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc) depending on the extent of skin involvement. This subclassification may not capture the entire variability of clinical phenotypes. The European Scleroderma Trials and Research (EUSTAR) database includes data on a prospective cohort of SSc patients from 122 European referral centers. This study was undertaken to perform a cluster analysis of EUSTAR data to distinguish and characterize homogeneous phenotypes without any a priori assumptions, and to examine survival among the clusters obtained. / Methods: A total of 11,318 patients were registered in the EUSTAR database, and 6,927 were included in the study. Twenty‐four clinical and serologic variables were used for clustering. / Results: Clustering analyses provided a first delineation of 2 clusters showing moderate stability. In an exploratory attempt, we further characterized 6 homogeneous groups that differed with regard to their clinical features, autoantibody profile, and mortality. Some groups resembled usual dcSSc or lcSSc prototypes, but others exhibited unique features, such as a majority of lcSSc patients with a high rate of visceral damage and antitopoisomerase antibodies. Prognosis varied among groups and the presence of organ damage markedly impacted survival regardless of cutaneous involvement. / Conclusion: Our findings suggest that restricting subsets of SSc patients to only those based on cutaneous involvement may not capture the complete heterogeneity of the disease. Organ damage and antibody profile should be taken into consideration when individuating homogeneous groups of patients with a distinct prognosis
    corecore