Introduction EMMA S. NORMAN; ALICE COHEN; KAREN BAKKER
Water without Borders?,
10/2013
Book Chapter
The title of this book asks readers to envision the possibility of water without borders. This vision may seem obvious: Water is already “without borders” in the sense that it is continually flowing ...across boundaries of all kinds – political, ecological, social, and economic. Yet borders remain crucial for water, for two reasons. First, the (geo)political borders embedded in contemporary water management systems have significant – and often negative – effects on watercourses and water users. Second, the reality of global water challenges and their local effects highlights the need for innovative strategies that are locally appropriate, globally coordinated, ecologically
Routeing of fusion proteins to the thylakoid lumen of the chloroplast was compared in vitro and in vivo. The Escherichia coli protein beta-lactamase was used as a passenger to study this ...intraorganellar sorting process. The first step, translocation of beta-lactamase into the chloroplast stroma, occurs properly both in vitro and in vivo and is dependent on the presence of a transit peptide in the protein construct. The second step, targeting towards the thylakoid lumen, is more complicated as was also observed previously when other passenger proteins were used. In vitro, the presence of a thylakoid transfer domain is not enough for routeing and proper processing. Only when the complete thylakoid lumen precursor plastocyanin was fused to beta-lactamase was the fusion protein processed adequately, but routeing was still incomplete. However, in vivo, the information present in the thylakoid transfer domain was the only requirement for proper transport towards the thylakoid lumen. These data show that in vivo, the only requirement for targeting of passenger proteins towards the thylakoid lumen is the presence of a transit peptide and a thylakoid transfer domain. Furthermore, we demonstrate that the in vitro import system does not necessarily reflect the in vivo situation with respect to intraorganellar sorting.
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