Strigolactones, phytohormones with diverse signaling activities, have a common structure consisting of two lactones connected by an enol-ether bridge. Strigolactones derive from carotenoids via a pathway involving the carotenoid cleavage dioxygenases 7 and 8 (CCD7 and CCD8) and the iron-binding protein D27. We show that D27 is a β-carotene isomerase that converts all-trans-β-carotene into 9-cis-β-carotene, which is cleaved by CCD7 into a 9-cis-configured aldehyde. CCD8 incorporates three oxygens into 9-cis-β-apo-10'-carotenal and performs molecular rearrangement, linking carotenoids with strigolactones and producing carlactone, a compound with strigolactone-like biological activities. Knowledge of the structure of carlactone will be crucial for understanding the biology of strigolactones and may have applications in combating parasitic weeds.

Quantitative MRI measures are diffusely abnormal in MS NAWM. These measures are, on average, more abnormal in NAWM regions in which new Gd+ lesions arise. After the appearance of Gd+ lesions, measures of PDN and MTR may provide more appealing markers of relatively irreversible tissue damage than measures of T2 and T1N.

To shed more light on the factors that promote micelle growth and induce the sphere-to-rod transition, three micellar systems formed by surfactants containing tetradecyltrimethylammonium (TTA + ) as cation and ortho-, meta-, or para-fluorobenzoate as counterion were investigated by conductivity, surface tension, and 1 H, 19 F, and 13 C NMR spectroscopy. The investigations illustrate that the transfer of TTA + /fluorobenzoate surfactants into the micellar phase and micelle growth are accompanied by characteristic changes in the NMR chemical shift and conductivity data, which were analyzed to determine the critical micelle concentration (cmc), the region of predominately spherical micelles, and the region of growth, where spherical aggregates are transformed to rodlike micelles. The studies reveal that TTA + /ortho-fluorobenzoate micelles with an averaged cmc of 2.51 mM remain roughly spherical even at surfactant concentrations as high as 70 mM. The graphs, in which the specific conductivity is plotted versus increasing surfactant concentration or in which the chemical shifts of the ortho-fluorobenzoate or the TTA + resonances are plotted versus increasing or the inverse of increasing surfactant concentration, give rise to a single breakpoint at the onset of micellization. In contrast, the NMR and conductivity plots of TTA + /meta-and para-fluorobenzoate micelles with averaged cmc values of 1.29 and 1.38 mM, respectively, show two breakpoints, one at the cmc and one at total surfactant concentrations 10 times the cmc. This second cmc indicates that TTA + / meta-and para-fluorobenzoate micelles change shape and grow from roughly spherical to rodlike aggregates at higher surfactant concentration. The NMR data reveal that aggregate growth is not an abrupt but a rather continuous process and that the positioning of the benzoate ions at the micellar interface along with their reduction of headgroup repulsions are the major contributors to micelle growth. The meta-and para-fluorobenzoates intercalate among the + N(CH3)3 headgroups thereby forming tight ion pairs, reducing headgroup repulsions, and inducing growth. Contrary, the ortho-fluorobenzoate ions penetrate the micellar interface more deeply and move toward the palisade layer. This positioning does not enable the anions to reduce effectively the unfavorable electrostatic headgroup interactions, and as a result, TTA + /orthofluorobenzoate micelles remain spherical even at high surfactant concentrations.

a b s t r a c tStrigolactones are phytohormones synthesized from carotenoids via a stereospecific pathway involving the carotenoid cleavage dioxygenases 7 (CCD7) and 8. CCD7 cleaves 9-cis-b-carotene to form a supposedly 9-cis-configured b-apo-10 0 -carotenal. CCD8 converts this intermediate through a combination of yet undetermined reactions into the strigolactone-like compound carlactone. Here, we investigated the substrate and stereo-specificity of the Arabidopsis and pea CCD7 and determined the stereo-configuration of the b-apo-10 0 -carotenal intermediate by using Nuclear Magnetic Resonance Spectroscopy. Our data unequivocally demonstrate the 9-cis-configuration of the intermediate. Both CCD7s cleave different 9-cis-carotenoids, yielding hydroxylated 9-cis-apo-10 0 -carotenals that may lead to hydroxylated carlactones, but show highest affinity for 9-cis-b-carotene.

For developing clinically useful porphyrin drugs, it is essential to characterize porphyrin-membrane interactions and to determine the factors that modulate such interactions. To this end, four uniquely p-phenyl-substituted tetraphenylporphyrins were synthesized. These water-insoluble, unsymmetrically substituted porphyrins were allowed to diffuse into aqueous micellar solutions formed by the surfactants tetradecyltrimethylammonium bromide (TTAB), sodium dodecyl sulfate (SDS), and poly(ethylene glycol)p-t-octylphenol (TX-100). The abilities of the porphyrins to localize in these micelles were determined by UV-vis and NMR spectroscopy. The data show that the NO2-phenyl-substituted porphyrin did not diffuse into any of the micellar solutions. The COO --substituted porphyrin was solubilized in cationic TTAB and in nonionic TX-100 micellar solutions under neutral and basic conditions. The NH3 + -substituted porphyrin incorporated in anionic SDS micelles at pH ) 2 and in TX-100 micelles at pH 2 and 7. These results emphasize that charge and polarity of the porphyrin substituent and its electrostatic interactions with the micelles play important roles in incorporating porphyrins with charged substituents into micelles. The OH-phenyl-substituted porphyrin incorporated into both neutral and basic TTAB and TX-100 micellar solutions in the highest concentrations, which reveals that a hydroxy substituent placed at the porphyrin periphery significantly increases the tendency of the porphyrin to embed in cationic and nonionic micelles. The data further demonstrate that all porphyrins are monodispersed in given micelles. In terms of porphyrin location, the data suggest that the COO --and NH3 + -phenyl-substituted porphyrins localize in the hydrophobic interior of ionic micelles, whereas the OH-phenyl-substituted porphyrin adopts a location in the more polar domains of cationic micelles. In nonionic micelles, the COO --, NH3 + -, and OHphenyl-substituted porphyrins seem to orient themselves toward the water-micelle interface. An intercalation among the surfactant chains is proposed.

Chronic infection with hepatitis C virus (HCV) is one of the main causes of hepatocellular carcinoma. However, the molecular mechanisms linking the infection to cancer development remain poorly understood. Here we used HCV‐infected cells and liver biopsies to study how HCV modulates the glutaminolysis pathway, which is known to play an important role in cellular energetics, stress defense, and neoplastic transformation. Transcript levels of glutaminolytic factors were quantified in Huh7.5 cells or primary human hepatocytes infected with the Japanese fulminant hepatitis 1 HCV strain as well as in biopsies of chronic HCV patients. Nutrient deprivation, biochemical analysis, and metabolite quantification were performed with HCV–infected Huh7.5 cells. Furthermore, short hairpin RNA vectors and small molecule inhibitors were used to investigate the dependence of HCV replication on metabolic changes. We show that HCV modulates the transcript levels of key enzymes of glutamine metabolism in vitro and in liver biopsies of chronic HCV patients. Consistently, HCV infection increases glutamine use and dependence. We finally show that inhibiting glutamine metabolism attenuates HCV infection and the oxidative stress associated with HCV infection. Conclusion: Our data suggest that HCV establishes glutamine dependence, which is required for viral replication, and, importantly, that glutamine addiction is a hallmark of tumor cells. While HCV induces glutaminolysis to create an environment favorable for viral replication, it predisposes the cell to transformation. Glutaminolytic enzymes may be interesting therapeutic targets for prevention of hepatocarcinogenesis in chronic hepatitis C. (Hepatology 2017;65:789‐803).

Strigolactones are a new class of phytohormones synthesized from carotenoids via carlactone. The complex structure of carlactone is not easily deducible from its precursor, a cis-configured β-carotene cleavage product, and is thus formed via a poorly understood series of reactions and molecular rearrangements, all catalyzed by only one enzyme, the carotenoid cleavage dioxygenase 8 (CCD8). Moreover, the reactions leading to carlactone are expected to form a second, yet unidentified product. In this study, we used C and O-labeling to shed light on the reactions catalyzed by CCD8. The characterization of the resulting carlactone by LC-MS and NMR, and the identification of the assumed, less accessible second product allowed us to formulate a minimal reaction mechanism for carlactone generation.

1H high resolution magic angle spinning (HR-MAS) NMR spectroscopy was applied in combination with multivariate statistical analyses to study the metabolic response of whole cells to the treatment with a hexacationic ruthenium metallaprism [1]6+ as potential anticancer drug. Human ovarian cancer cells (A2780), the corresponding cisplatin resistant cells (A2780cisR), and human embryonic kidney cells (HEK-293) were each incubated for 24 h and 72 h with [1]6+ and compared to untreated cells. Different responses were obtained depending on the cell type and incubation time. Most pronounced changes were found for lipids, choline containing compounds, glutamate and glutathione, nucleotide sugars, lactate, and some amino acids. Possible contributions of these metabolites to physiologic processes are discussed. The time-dependent metabolic response patterns suggest that A2780 cells on one hand and HEK-293 cells and A2780cisR cells on the other hand may follow different cell death pathways and exist in different temporal stages thereof.