52 research outputs found
Characterization of callase (β-1,3-d-glucanase) activity during microsporogenesis in the sterile anthers of Allium sativum L. and the fertile anthers of A. atropurpureum
We examined callase activity in anthers of sterile Allium sativum (garlic) and fertile Allium atropurpureum. In A. sativum, a species that produces sterile pollen and propagates only vegetatively, callase was extracted from the thick walls of A. sativum microspore tetrads exhibited maximum activity at pH 4.8, and the corresponding in vivo values ranged from 4.5 to 5.0. Once microspores were released, in vitro callase activity peaked at three distinct pH values, reflecting the presence of three callase isoforms. One isoform, which was previously identified in the tetrad stage, displayed maximum activity at pH 4.8, and the remaining two isoforms, which were novel, were most active at pH 6.0 and 7.3. The corresponding in vivo values ranged from pH 4.75 to 6.0. In contrast, in A. atropurpureum, a sexually propagating species, three callase isoforms, active at pH 4.8–5.2, 6.1, and 7.3, were identified in samples of microsporangia that had released their microspores. The corresponding in vivo value for this plant was 5.9. The callose wall persists around A. sativum meiotic cells, whereas only one callase isoform, with an optimum activity of pH 4.8, is active in the acidic environment of the microsporangium. However, this isoform is degraded when the pH rises to 6.0 and two other callase isoforms, maximally active at pH 6.0 and 7.3, appear. Thus, factors that alter the pH of the microsporangium may indirectly affect the male gametophyte development by modulating the activity of callase and thereby regulating the degradation of the callose wall
Plasticity of maritime pine (Pinus pinaster) wood-forming tissues during a growing season
Research• The seasonal effect is the most significant external source of variation affecting
vascular cambial activity and the development of newly divided cells, and hence
wood properties. Here, the effect of edapho-climatic conditions on the phenotypic
and molecular plasticity of differentiating secondary xylem during a growing season
was investigated.
• Wood-forming tissues of maritime pine (Pinus pinaster) were collected from the
beginning to the end of the growing season in 2003. Data from examination of fibre
morphology, Fourier-transform infrared spectroscopy (FTIR), analytical pyrolysis, and
gas chromatography/mass spectrometry (GC/MS) were combined to characterize the
samples. Strong variation was observed in response to changes in edapho-climatic
conditions.
• A genomic approach was used to identify genes differentially expressed during
this growing season. Out of 3512 studied genes, 19% showed a significant seasonal
effect. These genes were clustered into five distinct groups, the largest two representing
genes over-expressed in the early- or late-wood-forming tissues, respectively. The other
three clusters were characterized by responses to specific edapho-climatic conditions.
• This work provides new insights into the plasticity of the molecular machinery
involved in wood formation, and reveals candidate genes potentially responsible for
the phenotypic differences found between early- and late-wood
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Are researchers deliberately bypassing the technology transfer office? An analysis of TTO awareness
Most universities committed to the commercialization of academic research have established technology transfer offices (TTOs). Nonetheless, many researchers bypass these TTOs and take their inventions directly to the marketplace. While TTO bypassing has typically been portrayed as deliberate and undesirable behavior, we argue that it could be unintentional as many researchers may simply be unaware of the TTO’s existence. Taking an information-processing perspective and using data on 3250 researchers in 24 European universities, we examine researcher attributes associated with TTO awareness. Our evidence confirms that only a minority of researchers are aware of the existence of a TTO at their university. TTO awareness is greater among researchers who possess experience as entrepreneurs, closed many research and consulting contracts with industry partners, conduct research in medicine, engineering or life sciences, or occupy postdoctoral positions. Policy implications of these findings are discussed
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The influence of organizational culture and climate on entrepreneurial intentions among research scientists
Over the past decades, universities have increasingly become involved in entrepreneurial activities. Despite efforts to embrace their ‘third mission’, universities still demonstrate great heterogeneity in terms of their involvement in academic entrepreneurship. This papers adopts an institutional perspective to understand how organizational characteristics affect research scientists’ entrepreneurial intentions. Specifically, we study the impact of university culture and climate on entrepreneurial intentions, including intentions to spin off a company, to engage in patenting or licensing and to interact with industry through contract research or consulting. Using a sample of 437 research scientists from Swedish and German universities, our results reveal that the extent to which universities articulate entrepreneurship as a fundamental element of their mission fosters research scientists’ intentions to engage in spin-off creation and intellectual property rights, but not industry-science interaction. Furthermore, the presence of university role models positively affects research scientists’ propensity to engage in entrepreneurial activities, both directly and indirectly through entrepreneurial self-efficacy. Finally, research scientists working at universities which explicitly reward people for ‘third mission’ related output show higher levels of spin-off and patenting or licensing intentions. This study has implications for both academics and practitioners, including university managers and policy makers
JIMS Discussion Paper Series DP 280109
We conjecture that the mobility of academic scientists increases the propensity of
such agents to engage in academic entrepreneurship. Our empirical analysis is based
on a survey of researchers at the Max Planck Society in Germany. We find that
mobile scientists are more likely to become nascent entrepreneurs. Thus, it appears
that citizenship and foreign-education are important determinants of the early stages
of academic entrepreneurship.Jerusalem Institute for Market Studie
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