Woordgroepvers

Any metrical utterance has constituents founded in language and in metrics. The totality cannotconsist metrically of less than a verse and two segments, and linguistically of less than a sentence. Theprinciples governing metrical structure are that of partition and symmetry. The totality is thus dividedinto segments by (a) a word boundary marked by rhyme (in Afrikaans and English) or the repetition of aword (in Sepedi), or (b) a phrase boundary. Symmetry is realized by rhyme, quantitative/stress rhythm,an arrangement of units of meaning (only where the segments are divided by a phrase boundary), therepetition of (i) the same number of syllables and (ii) the same number of words. The Sepedi verse is aphrase verse, and that means that:(a) the segments are divided by a phrase boundary;(b) equivalence or symmetry is realized by (i) the repetition of a word or a phrase, (ii) an arrangementof units of meaning and (iii) quantitative rhythm.’n Taaluiting in versvorm bestaan uit linguistiese en metriese eenhede. Die versgeheel bestaan uit minstens’n sin en ’n vers en twee segmente. Die beginsels wat versvorm onderlê, is verdeling en ekwivalensie.Die geheel word deur (a) ’n woordgrens deur rym (in Afrikaans en Engels) en ’n woord (in Sepedi)gemarkeer, of (b) ’n woordgroepgrens in twee segmente verdeel. Ekwivalensie word bewerkstellig deurrym, aksent-/kwantitatiewe ritme, woord- of woordgroepherhaling, die herhaling van ’n gelyke getallettergrepe of woorde, of die ordening van betekeniseenhede (maar slegs waar ’n sintaktiese snit asverdeler optree). Die Sepedivers is ’n woordgroepvers, en dit beteken dat:(a) die segmente deur ’n sintaktiese snit verdeel word, en(b) ekwivalensie deur (i) die ordening van betekeniseenhede, (ii) die herhaling van ’n woord of ’nwoordgroep en (iii) die herhaling van ’n gelyke getal kwantitatiewe lettergreepkruine bepaalword.Article text in Afrikaan

Fourth-Generation Epac-Based FRET Sensors for cAMP Feature Exceptional Brightness, Photostability and Dynamic Range: Characterization of Dedicated Sensors for FLIM, for Ratiometry and with High Affinity

Epac-based FRET sensors have been widely used for the detection of cAMP concentrations in living cells. Originally developed by us as well as others, we have since then reported several important optimizations that make these sensors favourite among many cell biologists. We here report cloning and characterization of our fourth generation of cAMP sensors, which feature outstanding photostability, dynamic range and signal-to-noise ratio. The design is based on mTurquoise2, currently the brightest and most bleaching-resistant donor, and a new acceptor cassette that consists of a tandem of two cp173Venus fluorophores. We also report variants with a single point mutation, Q270E, in the Epac moiety, which decreases the dissociation constant of cAMP from 9.5 to 4 μM, and thus increases the affinity ~ 2.5-fold. Finally, we also prepared and characterized dedicated variants with non-emitting (dark) acceptors for single-wavelength FLIM acquisition that display an exceptional near-doubling of fluorescence lifetime upon saturation of cAMP levels. We believe this generation of cAMP outperforms all other sensors and therefore recommend these sensors for all future studies