A promiscuous archaeal cardiolipin synthase enables construction of diverse natural and unnatural phospholipids

Cardiolipins (CL) are a class of lipids involved in the structural organization of membranes, enzyme functioning, and osmoregulation. Biosynthesis of CLs has been studied in eukaryotes and bacteria, but has been barely explored in archaea. Unlike the common fatty acyl chain-based ester phospholipids, archaeal membranes are made up of the structurally different isoprenoid-based ether phospholipids, possibly involving a different cardiolipin biosynthesis mechanism. Here, we identified a phospholipase D motif-containing cardiolipin synthase (MhCls) from the methanogen Methanospirillum hungatei. The enzyme was overexpressed in Escherichia coli, purified, and its activity was characterized by LC-MS analysis of substrates/products. MhCls utilizes two archaetidylglycerol (AG) molecules in a transesterification reaction to synthesize glycerol-di-archaetidyl-cardiolipin (Gro-DACL) and glycerol. The enzyme is non-selective to the stereochemistry of the glycerol-backbone and the nature of the lipid tail, as it also accepts phosphatidylglycerol (PG) to generate glycerol-di-phosphatidyl-cardiolipin (Gro-DPCL). Remarkably, in the presence of AG and PG, MhCls formed glycerol-archaetidyl-phosphatidyl-cardiolipin (Gro-APCL), an archaeal-bacterial hybrid cardiolipin species that so far has not been observed in nature. Due to the reversibility of the transesterification, in the presence of glycerol, Gro-DPCL can be converted back into two PG molecules. In the presence of other compounds that contain primary hydroxyl groups (e.g., alcohols, water, sugars), various natural and unique unnatural phospholipid species could be synthesized, including multiple di-phosphatidyl-cardiolipin species. Moreover, MhCls can utilize a glycolipid in the presence of phosphatidylglycerol to form a glycosyl-mono-phosphatidyl-cardiolipin species, emphasizing the promiscuity of this cardiolipin synthase, that could be of interest for bio-catalytic purposes

Tumor infiltrating lymphocytes expanded from pediatric neuroblastoma display heterogeneity of phenotype and function

Adoptive transfer of ex vivo expanded tumor infiltrating lymphocytes (TILs) has led to clinical benefit in some patients with melanoma but has not demonstrated convincing efficacy in other solid cancers. Whilst the presence of TILs in many types of cancer is often associated with better clinical prognosis, their function has not been systematically evaluated across cancer types. Responses to immunological checkpoint inhibitors in a wide range of cancers, including those for which adoptive transfer of expanded TILs has not shown clinical benefit, has clearly delineated a number of tumor type associated with tumor-reactive lymphocytes capable of effecting tumor remissions. Neuroblastoma is an aggressive childhood solid cancer in which immunotherapy with GD2-directed antibodies confers a proven survival advantage through incompletely understood mechanisms. We therefore evaluated the feasibility of ex vivo expansion of TILs from freshly resected neuroblastoma tumors and the potential therapeutic utility of TIL expansions. TILs were successfully expanded from both tumor biopsies or resections. Significant numbers of NKT and γδT cells were identified alongside the mixed population of cytotoxic (CD8+) and helper (CD4+) T cells of both effector and central memory phenotypes. Isolated TILs were broadly non-reactive against autologous tumor and neuroblastoma cell lines, so enhancement of neuroblastoma killing was attained by transducing TILs with a second-generation chimeric antigen receptor (CAR) targeting GD2. CAR-TILs demonstrated antigen-specific cytotoxicity against tumor cell lines. This study is the first to show reproducible expansion of TILs from pediatric neuroblastoma, the high proportion of innate-like lymphocytes, and the feasibility to use CAR-TILs therapeutically

Redox properties of the iron-sulfur clusters in activated Fe-hydrogenase from Desulfovibrio vulgaris (Hildenborough)

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65750/1/j.1432-1033.1992.tb17261.x.pd

Refashioning the Ethiopian monarchy in the twentieth century: An intellectual history

This article traces the shift in the Ethiopian monarchical ideology from lineage as symbolic Christian filiation to dynasty as a political genealogy of sovereign power. From the end of the nineteenth century, and more prominently under Haylä Səllase, Ethiopian state sources started qualifying the Ethiopian ruling dynasty as ‘unbroken’ in history. A record of ‘uninterrupted’ power allowed the Ethiopian government to politically appropriate past glories and claim them as ‘ours’, thus compensating for the political weakness of the present with the political greatness of the past. The ideological rebranding of the Ethiopian monarchy in the 1930s brought Ethiopia closer to Japan, and the ‘eternalist clause’ of the Meiji constitution offered a powerful model of how to recodify dynasty in modern legal terms. An intellectual history of dynasty in the Ethiopian context sees the concept simultaneously associated with both hegemonic and counter-hegemonic political projects. The narratives of continuity enabled by the dynastisation of history were successful in invigorating the pro-Ethiopian front during the Italian occupation of Ethiopia (1936-1941), but served at the same time to reinforce domestic mechanisms of class, political and cultural domination

Classifying modules over K-theory spectra

AbstractThe category of modules over an S-algebra (A∞ or E∞ ring spectrum) has many of the good properties of the category of spectra. When the homotopy groups of the S-algebra in question form a sufficiently nice ring, it is possible to see the deviation of the category of modules over an S-algebra from the corresponding algebraic module category. In particular, many algebraic modules are realized as homotopy groups of topological modules over S-algebras. Examples studied include real and complex K-theory, both connective and periodic. Further, Bousfield localization by a smashing spectrum is shown to yield a category of modules over the localized sphere. For periodic K-theory, these methods yield an algebraic criterion to determine when a local spectrum is a module over the K-theory S-algebra, real or complex