In vivo reports

Preliminary studies, which have repeated many of the in vitro experiments in vivo, reported that the differentiation between stratum corneum and viable epidermis is at least as good, if not better in vivo and that many of the other experiments are similarly reproduced [16]. 

More broadly, the azide might serve as an in vivo reporter of glycan expression. In principle, any sugar could metabolically be labeled with an azide if the biosynthetic enzymes are tolerant of azido substrates. 

Bennett J, Anand V, Acland GM, Maguire AM. Cross-species comparison of in vivo reporter gene expression after rAAV-mediated retinal transduction. Meth Enzymol 2000 316 777-789. 

Figure 4 Strategies for the application of CoA analogues. For in vitro studies appropriate analogues are prepared from a suitable precursor, purified, and characterized if necessary, and then normally used as mechanism-based probes and inhibitors (panel A). When CoA analogues are used for the in vitro site-specific modification of proteins by transfer of a reporter label to a carrier protein module using a PPTase enzyme, the analogue can be prepared and used in situ (panel B). In vivo reporter labeling is made possible when cells are provided with suitably modified pantothenamide precursors, which are subsequently transformed into the respective CoA analogues and transferred a carrier protein by the cell s native CoA biosynthesis (CoaADE) and PPTase enzymes. The labeled protein can be recovered from the cells by cell lysis.

In these experiments flash fluorescence was used as an independent technique in which to distinguish two broad populations of photosystem II reaction centers. Flash fluorescence has been used (7) to monitor the redox state of the primary quinone at various times after complete photoreduction by a saturating flash. The redox state of Qa was monitored by flash fluorescence at times ranging from 120 ps to 100 s after a saturating flash. The results indicate that a significant fraction of photosystem II reaction centers have a Qa" half-time oxidation of about 2 s. Flash fluorescence thus serves as an independent, non-invasive measurement upon an in vivo system which confirms the existence of a significant fraction of inactive photosystem II in vivo reported in earlier work (5). It also confirms an earlier conclusion (5,6) that the slow turnover rate of inactive centers is due to a very slow oxidation rate of Qa" in these centers. 

---