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Plant protoplasts as a model system to study phytochrome-regulated changes in the plasma membrane
No full textProtoplasts, isolated from the primary leaves of dark-grown wheat ( Triticum aestivum L.), have been used as a model system to study phytochrome-regulated changes of the plasma membrane. Such protoplasts only swelled after red light (R)-irradiation, when Ca2+was present in the medium. Far-red light (FR), after R, prevented swelling, indicating phytochrome involvement. Swelling was inhibited when La3+or the Ca 2+-channelblocker Verapamil were added. Swelling was induced in darkness by the Ca 2+-ionophore A23187 and the calmodulin antagonist W 7 . It is proposed that Rirradiation leads to opening of Ca 2+-channels, resulting in an increase of the cytoplasmic [Ca 2+] and protoplast swelling.The effect of modulators of G-proteins and the phosphatidylinositol cycle, as known in animal cells, on the swelling response was examined. The R-induced swelling was inhibited by GDP-β-S and by neomycin, Li +and H 7 . In darkness, swelling was found when GTP-γ-S or PMA were added to the protoplasts. All agonists and antagonists used, influenced the swelling response, as predicted by transposition of the animal model to plants. This suggests that R-irradiation, leads to activation of a G- protein, which results in the opening of Ca 2+-channels.Plant hormones also induced protoplast swelling in the presence of Ca 2+, while swelling was inhibited by GDP-β-S Acetylcholine induced, contrary to R-irradiation, swelling in the absence of Ca 2+, when K +or Na +were present in the medium. This swelling was not inhibited by GDP-β-S The Ca 2+-sensitive dye murexide, has been used to monitor phytochrome-regulated changes in the [Ca 2+] of the medium. Red light induced a Ca 2+-efflux, while FR reversed this effect. The R-induced efflux was inhibited by Verapamil and W 7 by approx. 75%. Therefore, the efflux, via a Ca 2+-ATPase, appears to be dependent on the activation of Ca 2+-channels and a Ca 2+-influx.The fluidity of the protoplast plasma membrane was studied, using the fluorescent membrane probe DPH. After R the anisotropy of DPH (r f ) was higher, indicating a decrease in membrane fluidity. In darkness, r f also increased upon osmotically induced protoplast swelling. It is not clear, whether R causes changes in membrane fluidity, independent of changes in volume.The observed changes in plasma membrane properties after R-irradiation, show that protoplasts are an useful tool for studying phytochrome action in higher plants.</TT
Programma In Funere Clarissimi Experientissimique Viri, Johannis Henrici Bossen/ Medic. Ddi, civitatisque Helmstadiensis Medici ordinarii, P.P. / [Prorector Academiae Iuliae Valentinus Henricus Voglerus ...]
No full textSexual Diversity in the Field of Action in School. Concepts from Educational Science and Specialist Didactics
No full textProgrammata Tria in Funeribus Filii, Filiae, demum Coniugis pie defunctorum; Viri praestant. Johannis Bossen oeconomi bene meriti, P.P. / [Provicerector Et Senatus Academiae Iuliae ...]
No full textDavid A. Bossen
No full textDavid A. Bossen was born on January 9, 1927 in Clinton, Iowa. He earned a B.S. in Industrial Management at Massachusetts Institute of Technology in 1951 after serving in the United States Marine Corps from 1945-1946.
Bossen’s industrial career began with Industrial Nucleonics Corporation in Columbus, Ohio, where he become Vice President, General Manager, and Chief Operating Officer. In 1967, Bossen relocated to California where in 1968 he founded one of Silicon Valley’s first technology companies, Measurex, an Industrial Automated Process Control System. He held several patents in the field of control systems. In 1997, Bossen sold Measurex to Honeywell Industries, but continued as CEO and Chair of the Board. Upon his retirement in 2000, he was named Chair Emeritus.
Bossen served as a member of the Maine Pulp and Paper Foundation Board of Directors. He established the Bossen Family Scholarship Fund and donated a Measurex, Vision 2002 Computer Integrated Manufacturing system to control the University\u27s pilot paper machine. David Bossen died April 21, 2015.https://digitalcommons.library.umaine.edu/ppf_images/1025/thumbnail.jp
The Chicago Couriers Union, 2003-2010 : a case study in solidarity unionism
No full textHarvard University doctoral candidate Reverend Colin Bossen delivers a talk entitled, "The Chicago Couriers Union, 2003-2010: A Case Study in Solidarity Unionism." Bossen describes the creation of the courier union in which he participated and documented. He talks about management's actions and the reactions of the couriers; firings, NLRB filings, and grass roots organizing efforts. Bossen explains the couriers' relationship with the I.W.W. and their paid organizer. He also recounts the successes and failures of the efforts as examples of how "solidarity unionism" can improve working conditions for workers. Bossen answers questions from the audience. He is introduced by Michigan State University Professor John P. Beck. Part of the "Our Daily Work/Our Daily Lives" Brown Bag series co-sponsored by the MSU School of Human Resources and Labor Relations and the MSU Museum. Held in the MSU Museum Auditorium
Sexual Diversity in the Field of Action in School. Concepts from Educational Science and Specialist Didactics
No full textBomen en bossen
No full textIn de bossen is veel koolstof opgeslagen. Bomen planten helpt daarom bij de bestrijding van het broeikaseffect. Maar tegelijkertijd hebben bossen, zoals de meeste ecosystemen, hinder van klimaatverandering. Het is zeer twijfelachtig of deze langzaam veranderende systemen de poolwaarts schuivende klimaatzones kunnen volge
Plantendiversiteit in alluviale bossen gaat kopje onder. Onverwachte vegetatieontwikkeling in jong en oude bossen in amper dertig jaar
No full textIn de periode 1977–1983 stelde Martin Hermy een classifi catie op van bosplantengemeenschappen in oude
bossen en in jonge bossen op voormalige landbouwgronden. Hiervoor werden in westelijk Vlaanderen
niet minder dan 640 vegetatieopnamen uitgevoerd, gespreid over 183 bossen. De studie toonde dat de
diversiteit en samenstelling van de kruidlaag grondig verschilt tussen jonge en oude bossen. Nu 30 jaar
later deden we het werk nog eens over voor de alluviale bostypes en gingen na of de verschillen tussen de
oude en de jonge bossen kleiner geworden zijn.status: Publishe
De verdamping van bossen
Get PDFAls de verdamping van bossen wordt geschat met de tabel van de Studiecommissie Water Natuur Bos Landschap, kan er een relatieve fout in het neerslagoverschot optreden van 100 ten opzichte van een goed gekalibreerd model. Ook als de verdamping wordt berekend met een voor de interceptie aangepaste formulering van de verdamping volgens Makkink, geeft dat een grote onnauwkeurigheid. Aanbevolen wordt om de verdamping van bossen te berekenen met modellen, zoals het weerstandsmodel van Penman-Monteith
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