| 2 | Comparative functional genomics identifies an iron-limited bottleneck in a Saccharomyces cerevisiae strain with a cytosolic-localized isobutanol pathway显示文摘Metabolic engineering strategies have been successfully implemented to improve the production of isobutanol,a next-generation biofuel,in Saccharomyces cerevisiae.Here,we explore how two of these strategies,pathway re-localization and redox cofactor-balancing,affect the performance and physiology of isobutanol producing strains.We equipped yeast with isobutanol cassettes which had either a mitochondrial or cytosolic localized isobutanol pathway and used either a redox-imbalanced(NADPH-dependent)or redox-balanced(NADH-dependent)ketol-acid reductoisomerase enzyme.We then conducted transcriptomic,proteomic and metabolomic analyses to elucidate molecular differences between the engineered strains.Pathway localization had a large effect on isobutanol production with the strain expressing the mitochondrial-localized enzymes producing 3.8-fold more isobutanol than strains expressing the cytosolic enzymes.Cofactor-balancing did not improve isobutanol titers and instead the strain with the redox-imbalanced pathway produced 1.5-fold more isobutanol than the balanced version,albeit at low overall pathway flux.Functional genomic analyses suggested that the poor performances of the cytosolic pathway strains were in part due to a shortage in cytosolic Fe-S clusters,which are required cofactors for the dihydroxyacid dehydratase enzyme.We then demonstrated that this cofactor limitation may be partially recovered by disrupting iron homeostasis with a fra2 mutation,thereby increasing cellular iron levels.The resulting isobutanol titer of the fra2 null strain harboring a cytosolic-localized isobutanol pathway outperformed the strain with the mitochondrial-localized pathway by 1.3-fold,demonstrating that both localizations can support flux to isobutanol. | Francesca V.Gambacorta Ellen R.Wagner Tyler B.Jacobson Mary Tremaine Laura K.Muehlbauer Mick A.McGee Justin J.Baerwald Russell L.Wrobel John F.Wolters Mike Place Joshua J.Dietrich Dan Xie Jose Serate Shabda Gajbhiye Lisa Liu Maikayeng Vang-Smith Joshua J.Coon Yaoping Zhang Audrey P.Gasch Daniel Amador-Noguez Chris Todd Hittinger Trey K.Sato Brian F.Pfleger | 2022 | Synthetic and Systems Biotechnology2022，7，2： | 1 |
| 3 | Investigation of experimental observables in search of the chiral magnetic effect in heavy-ion collisions in the STAR experiment显示文摘The chiral magnetic effect(CME)is a novel transport phenomenon,arising from the interplay between quantum anomalies and strong magnetic fields in chiral systems.In high-energy nuclear collisions,the CME may survive the expansion of the quark-gluon plasma fireball and be detected in experiments.Over the past two decades,experimental searches for the CME have attracted extensive interest at the Relativistic Heavy Ion Collider(RHIC)and the Large Hadron Collider(LHC).The main goal of this study is to investigate three pertinent experimental approaches:the$\gamma$correlator,the R correlator,and the signed balance functions.We exploit simple Monte Carlo simulations and a realistic event generator(EBE-AVFD)to verify the equivalence of the core components among these methods and to ascertain their sensitivities to the CME signal and the background contributions for the isobar collisions at the RHIC. | Subikash Choudhury Xin Dong Jim Drachenberg James Dunlop ShinIchi Esumi 冯毅程 Evan Finch 胡昱 Jiangyong Jia Jerome Lauret Wei Li 廖劲峰 林裕富 Mike Lisa Takafumi Niida Robert Lanny Ray Masha Sergeeva 申迪宇 施舒哲 Paul Sorensen 唐爱洪 Prithwish Tribedy Gene Van Buren Sergei Voloshin 王福强 王钢 徐浩洁 徐之湾 Nanxi Yao 赵杰 | 2022 | Chinese Physics C2022，46，1： | 0 |
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