Iodospirocyclization of Tryptamine-Derived Isocyanides:Formal Total Synthesis of Aspidofractinine

The N-iodosuccinimide-mediated spirocyclization of tryptamine-derived isocyanides to generate spiroindolenines is reported. The products contain both an imine and an imidoyl iodide as flexible handles for follow-up chemistry. Nucleophilic addition typically occurs chemoselectively on the imine moiety with complete diastereoselectivity, providing opportunities for the construction of complex molecular frameworks. The synthetic potential of the method was showcased in the formal total synthesis of (±)-aspidofractinine

Track D Social Science, Human Rights and Political Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138414/1/jia218442.pd

Hyperacidification of <i>Citrus</i> fruits by a vacuolar proton-pumping P-ATPase complex

The sour taste of Citrus fruits is due to the extreme acidification of vacuoles in juice vesicle cells via a mechanism that remained elusive. Genetic analysis in petunia identified two vacuolar P-ATPases, PH1 and PH5, which determine flower color by hyperacidifying petal cell vacuoles. Here we show that Citrus homologs, CitPH1 and CitPH5, are expressed in sour lemon, orange, pummelo and rangpur lime fruits, while their expression is strongly reduced in sweet-tasting “acidless” varieties. Down-regulation of CitPH1 and CitPH5 is associated with mutations that disrupt expression of MYB, HLH and/or WRKY transcription factors homologous to those activating PH1 and PH5 in petunia. These findings address a long-standing enigma in cell biology and provide targets to engineer or select for taste in Citrus and other fruits

Identificação de espécies de citros mediante polimorfismo enzimático Identification of citrus species by means of enzymatic polymorphism

Estudou-se, mediante polimorfismo enzimático em gel de poliacrilamida, a variabilidade genética das espécies de laranja-doce (Citrus sinensis); laranja-azeda (C. aurantium); tangerinas clementina (C. clementina), sunki (C. sunki), cleópatra (C. reshni) e poncã (C. rsticulata); lima-da-pérsia (C. limettioides); limão-galego (C. aurantifolia); limão-cravo (C. limonia) e trifoliata (Poncirus trifoliata). Extratos de folhas foram analisados para as isoenzimas de malato deidrogenase (MDH), enzima málica (ME), leucino amino peptidase (LAP), glutamato oxaloacetato transaminase (GOT), fosfoglucoisomerase (PGI), fosfoglucomutase (PGM) e isocitrato deidrogenase (IDH). Verificou-se grande variabilidade genética interespecífica, porém nenhuma entre os cultivares de laranja-doce. Foram encontradas algumas aloenzimas, além das referidas pela literatura em gel de amido, como aquelas de uma região próxima ao loco conhecido por Pgm-1, responsável por proteínas monoméricas. Este sistema, denominado PGM, revelou a maior diferenciação entre as espécies, tendo apresentado duas regiões distintas com 9 alelos. No sistema MDH, foram considerados dois locas codificando para proteínas diméricas com 7 alelos; no ME, um loco com 3 alelos; no LAP, possivelmente dois locos responsáveis por proteínas monoméricas com 4 alelos; no GOT, dois focos com 7 alelos; no PGI, um loco com 3 alelos e no IDH, um loco com 4 alelos.<br>The genetic diversity of citrus cultivars was studied by polyacrylamide gel electrophoresis on sweet orange (C. sinensis); tangerines (C. clementine, C. sunki, C. reshni, C. reticulata); Palestine lime (C. Iimettioides); West Indian lime (C. aurantifolia); Rangpur lime (C. limonia), Sour orange (C. aurantium) and Poncirus trifoliata. Citrus leaf extracts were analysed for isozymes of malato dehidrogenase (MDH), malic enzyme (ME), leucine aminopeptidase (LAP), glutamate oxaloacetate transaminase (GOT), phosphoglucose isomerase (PGI), phosphoglucose mutase (PGM) and isocitrate dehydrogenase (IDH). Interespecific differences were observed; but, none between intraespecific C. sinensis cultivars. Some allozymes were observed in addition to those reffered in the literature on starch gel; e.g., allozymes located next to the known Pgm-1 loci. The PGM system revealed the best differentiation between the cultivars. It showed monomeric proteins and 9 alleles. The MDH system had two loci with 7 alleles; the ME system one locus with 3 alleles; the LAP system one possible locus next to the known Lap-1 and 4 alleles; the GOT two loci for dimeric proteins with 7 alleles; the PGI one locus with 3 alleles; and, the IDH one locus with 4 alleles