A Demand-Centric Repositioning Strategy for Bike-Sharing Systems.

Transport-sharing systems are eco-friendly and the most promising services in smart urban environments, where the booming Internet of things (IoT) technologies play an important role in the smart infrastructure. Due to the imbalanced bike distribution, bikes and stalls in the docking stations could be unavailable when needed, leading to bad customer experiences. We develop a dynamic repositioning strategy for the management of bikes in this paper, which supports dispatchers to keep stations in service. Two open datasets are examined, and the exploratory data analysis presents that there is a significant difference of travel patterns between working and non-working days, where the former has an excess demand at rush hours and the latter is usually at a low demand. To evaluate the effect when the demand outstrips a station's capacity, we propose a non-linear scaling technique to transform demand patterns and perform the clustering analysis for each of five categories obtained from the sophisticated analysis of the dataset. Our repositioning strategy is developed according to the transformed demands. Compared with the previous work, numerical simulations reveal that our strategy has a better performance for high-demand stations, and thus can substantially reduce the repositioning cost, which brings benefit to bike-sharing operators for managing the city bike system.

NEIL1 protects against aflatoxin-induced hepatocellular carcinoma in mice.

Global distribution of hepatocellular carcinomas (HCCs) is dominated by its incidence in developing countries, accounting for >700,000 estimated deaths per year, with dietary exposures to aflatoxin (AFB1) and subsequent DNA adduct formation being a significant driver. Genetic variants that increase individual susceptibility to AFB1-induced HCCs are poorly understood. Herein, it is shown that the DNA base excision repair (BER) enzyme, DNA glycosylase NEIL1, efficiently recognizes and excises the highly mutagenic imidazole ring-opened AFB1-deoxyguanosine adduct (AFB1-Fapy-dG). Consistent with this in vitro result, newborn mice injected with AFB1 show significant increases in the levels of AFB1-Fapy-dG in Neil1-/- vs. wild-type liver DNA. Further, Neil1-/- mice are highly susceptible to AFB1-induced HCCs relative to WT controls, with both the frequency and average size of hepatocellular carcinomas being elevated in Neil1-/- The magnitude of this effect in Neil1-/- mice is greater than that previously measured in Xeroderma pigmentosum complementation group A (XPA) mice that are deficient in nucleotide excision repair (NER). Given that several human polymorphic variants of NEIL1 are catalytically inactive for their DNA glycosylase activity, these deficiencies may increase susceptibility to AFB1-associated HCCs.

DNA polymerase ζ limits chromosomal damage and promotes cell survival following aflatoxin exposure.

Routine dietary consumption of foods that contain aflatoxins is the second leading cause of environmental carcinogenesis worldwide. Aflatoxin-driven mutagenesis is initiated through metabolic activation of aflatoxin B1 (AFB1) to its epoxide form that reacts with N7 guanine in DNA. The resulting AFB1-N7-dG adduct undergoes either spontaneous depurination or imidazole-ring opening yielding formamidopyrimidine AFB1 (AFB1-Fapy-dG). Because this latter adduct is known to persist in human tissues and contributes to the high frequency G-to-T mutation signature associated with many hepatocellular carcinomas, we sought to establish the identity of the polymerase(s) involved in processing this lesion. Although our previous biochemical analyses demonstrated the ability of polymerase ζ (pol ζ) to incorporate an A opposite AFB1-Fapy-dG and extend from this mismatch, biological evidence supporting a unique role for this polymerase in cellular tolerance following aflatoxin exposure has not been established. Following challenge with AFB1, survival of mouse cells deficient in pol ζ (Rev3L-/-) was significantly reduced relative to Rev3L+/- cells or Rev3L-/- cells complemented through expression of the wild-type human REV3L. Furthermore, cell-cycle progression of Rev3L-/- mouse embryo fibroblasts was arrested in late S/G2 following AFB1 exposure. These Rev3L-/- cells showed an increase in replication-dependent formation of γ-H2AX foci, micronuclei, and chromosomal aberrations (chromatid breaks and radials) relative to Rev3L+/- cells. These data suggest that pol ζ is essential for processing AFB1-induced DNA adducts and that, in its absence, cells do not have an efficient backup polymerase or a repair/tolerance mechanism facilitating survival.

Domino Cyclization of 1,n-Enynes (n = 7, 8, 9) Giving Derivatives of Pyrane, Chromene, Fluorene, Phenanthrene and Dibenzo[7]annulene by Ruthenium Complexes.

Cyclization of the ether enyne 1 catalyzed by [Ru]NCCH3(+) ([Ru] = Cp(PPh3)2Ru) in CHCl3 generates a diastereomeric mixture of the substituted tetrahydropyran 11. Presumably, formation of an allenylidene complex is followed by a cyclization by nucleophilic addition of the olefinic group to Cγ of the ligand giving a boat-like six-membered ring. The diastereoselectivity is controlled by the 1,3-diaxial interaction. The vinylidene complex 7, a precursor of 11, is obtained from 1 and [Ru]Cl. In a mixture of MeOH/CHCl3, the domino cyclization of 1 further affords 14a, a chromene product catalytically. The second cyclization proceeds via nucleophilic addition of the resulting olefinic unit to Cα of 7. But the ether enyne 3 with a cyclopentyl ring on the olefinic unit undergoes only single cyclization due to steric effect. The propargyl alcohol and the two terminal methyl groups on the olefinic unit shape the cyclization. Thus, similar all-carbon 1,n-enynes (n = 7, 8, 9) 4-6 each with an aromatic linker undergo direct domino cyclization catalyzed by [Ru]NCCH3(+), to give derivatives of tricyclic fluorene, phenanthrene and dibenzo[7]annulene, respectively, with no intermediate observed.

Hepatoprotective Effect of Cuscuta campestris Yunck. Whole Plant on Carbon Tetrachloride Induced Chronic Liver Injury in Mice.

Cuscuta seeds and whole plant have been used to nourish the liver and kidney. This study was aimed to investigate the hepatoprotective activity of the ethanol extract of Cuscuta campestris Yunck. whole plant (CCEtOH). The hepatoprotective effect of CCEtOH (20, 100 and 500 mg/kg) was evaluated on carbon tetrachloride (CCl4)-induced chronic liver injury. Serum alanine aminotransferase, aspartate aminotransferase, triglyceride and cholesterol were measured and the fibrosis was histologically examined. CCEtOH exhibited a significant inhibition of the increase of serum alanine aminotransferase, aspartate aminotransferase, triglyceride and cholesterol. Histological analyses showed that fibrosis of liver induced by CCl4 were significantly reduced by CCEtOH. In addition, 20, 100 and 500 mg/kg of the extract decreased the level of malondialdehyde (MDA) and enhanced the activities of anti-oxidative enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRd) in the liver. We demonstrate that the hepatoprotective mechanisms of CCEtOH were likely to be associated to the decrease in MDA level by increasing the activities of antioxidant enzymes such as SOD, GPx and GRd. In addition, our findings provide evidence that C. campestris Yunck. whole plant possesses a hepatoprotective activity to ameliorate chronic liver injury.

Error-prone replication bypass of the primary aflatoxin B1 DNA adduct, AFB1-N7-Gua.

Hepatocellular carcinomas (HCCs) are the third leading cause of cancer deaths worldwide. The highest rates of early onset HCCs occur in geographical regions with high aflatoxin B1 (AFB1) exposure, concomitant with hepatitis B infection. Although the carcinogenic basis of AFB1 has been ascribed to its mutagenic effects, the mutagenic property of the primary AFB1-DNA adduct, AFB1-N7-Gua, in mammalian cells has not been studied extensively. Taking advantage of the ability to create vectors containing a site-specific DNA adduct, the mutagenic potential was determined in primate cells. This adduct was highly mutagenic following replication in COS-7 cells, with a mutation frequency of 45%. The spectrum of mutations was predominantly G to T base substitutions, a result that is consistent with previous mutation data derived from aflatoxin-associated HCCs. To assess which DNA polymerases (pol) might contribute to the mutational outcome, in vitro replication studies were performed. Unexpectedly, replicative pol δ and the error-prone translesion synthesis pol ζ were able to accurately bypass AFB1-N7-Gua. In contrast, replication bypass using pol κ was shown to occur with low fidelity and could account for the commonly detected G to T transversions.

Molecular basis of aflatoxin-induced mutagenesis-role of the aflatoxin B1-formamidopyrimidine adduct.

Aflatoxin B1 (AFB1) is a known carcinogen associated with early-onset hepatocellular carcinoma (HCC) and is thought to contribute to over half a million new HCCs per year. Although some of the fundamental risk factors are established, the molecular basis of AFB1-induced mutagenesis in primate cells has not been rigorously investigated. To gain insights into genome instability that is produced as a result of replicating DNAs containing AFB1 adducts, site-specific mutagenesis assays were used to establish the mutagenic potential of the persistent ring-opened AFB1 adduct, AFB1-formamidopyrimidine (AFB1-FAPY). This lesion was highly mutagenic, yielding replication error frequencies of 97%, with the predominant base substitution being a G to T transversion. This transversion is consistent with previous mutational data derived from aflatoxin-associated HCCs. In vitro translesion synthesis assays demonstrated that polymerase (pol) ζ was the most likely candidate polymerase that is responsible for the G to T mutations induced by this adduct.

A light-gated molecular brake with antilock and fluorescence turn-on alarm functions: application of singlet-state adiabatic cis → trans photoisomerization.

A light-gated molecular brake that displays both high braking power (∼10(7)) and high switching power (∼74%) is reported. The lower rate for brake-on than for brake-off switching of the pentiptycene rotor mimics the function of an antilock braking system (ABS) for vehicles on a loose surface. The brake is also armed with a fluorescence turn-on alarm for accidental deactivation of the ABS function by acids. All of these features are associated with the highly efficient singlet-state adiabatic cis → trans photoisomerization of the phenylstilbene chromophore.

Lysosomal targeting of phafin1 mediated by Rab7 induces autophagosome formation.

Autophagy orchestrates programmed cell death via crossroads of complex vesicle trafficking including autophagosome and lysosome interaction. Phafin1, an endosome proteins composed of Pleckstrin homology (PH) and Fab1-YotB-Vac1p-EEA1 (FYVE) domain membrane-binding domains, is involved in caspase-independent apoptosis. We report here that the increased expression of phafin1 and its FYVE domain caused the formation of enlarged endosomes. Phafin1 also modulates the membrane density of certain receptors and participates in endocytosis and autophagy processes. The PH-domain of phafin1 is dispensable for lysosomal targeting. Moreover, the tail-domain of phafin1 provides lysosomal targeting signature and the ability to induce autophagy that is mediated by Rab7 signaling. The results suggest that in addition to its role in endosome transport, phafin1 is also involved in lysosomal targeting and autophagosome formation.

Cyclization of aromatic propargyl alcohol with a thiophene group yielding naphthothiophene aldehyde induced by a ruthenium complex.

The reactions of [Cp(PPh(3))(2) RuCl] (Cp=cyclopentadienyl) with phenyl propargylic alcohol 1a, with a 3-thiophene group, are explored. The carbene complex 2a, obtained exclusively from this reaction at low temperature, contains the naphthothiophene group, which is formed through a new cyclization process between the thiophene group and the inner carbon of the triple bond. Details of this process have been revealed by conducting the reaction at room temperature, affording the allenylidene complex 3a as a side product. Complex 3a is not converted into 2a, indicating that the cyclization takes place while the triple bond is π coordinated to the metal center. Complex 2a reacts with oxygen in the presence of NEt(3) at room temperature to afford, in high yield, naphthothiophene aldehyde 4a, ONEt(3), OPPh(3), and [Cp(PPh(3))(2)RuCl]. Molecular O(2) is likely activated by coordination to the metal center when one of the phosphane ligands dissociates. Then, NEt(3) promotes the oxygenation process by reacting with the coordinated O(2) to afford ONEt(3) and possibly an unobserved oxo-carbene complex. Coupling of the oxo and carbene ligands then yields 4a and [Cp(PPh(3))(2) RuCl] in CHCl(3). In a solvent system containing MeOH, the oxygenation reaction affords a mixture of 4a and naphthothiophene ester 5a-1. The reactions of [Cp(dppf)RuCl] (dppf=1,1'-bis(diphenylphosphino)ferrocene) with 1a, also afford the carbene complex 2a', 4a, and 5a, which have been characterized by X-ray diffraction analyses. For the phenyl propargylic alcohol 1b, with a 2-thiophene substituent, different naphthothiophene aldehyde and ester compounds are also obtained in high yields through a similar cyclization process followed by oxygenation under mild conditions.

Analgesic and Anti-Inflammatory Activities of the Ethanolic Extract of Artemisia morrisonensis Hayata in Mice.

The aim of this study was to investigate the possible analgesic and anti-inflammatory mechanisms of the ethanolic extract of A. morrisonensis Hayata (AM(EtOH)). Two models were employed for evaluation of the analgesic effects: acetic acid-induced writhing response and formalin-induced paw licking. The results demonstrated that AM(EtOH) decreased writhing response for both the acetic acid assay and the licking time in the formalin test. The anti-inflammatory effect was evaluated by paw edema of mice induced by λ-carrageenan. AM(EtOH) significantly decreased induced paw edema three to four hours after λ-carrageenan injection. Additionally, the results indicated that the anti-inflammatory mechanism of AM(EtOH) may be due to the declined levels of nitric oxide (NO) and malondialdehyde (MDA) in the edematous paw. Furthermore, AM(EtOH) decreased the tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels, leading to the reduction of prostaglandins and subsequently alleviated edema. Isolation and purification of the AM(EtOH) extract determined p-hydroxyacetophenone to be a major component at 130 mg/g of extract. No mortality was observed in the acute toxicity test given at the dose of 10 g/kg. This study demonstrated the possible mechanisms for the analgesic and anti-inflammatory effects of AM(EtOH) for mice and provided evidence for the ethnobotanical uses of A. morrisonensis in treating inflammatory diseases.

Antioxidant, Antinociceptive, and Anti-Inflammatory Activities from Actinidia callosa var. callosa In Vitro and In Vivo.

Actinidia callosa var. callosa has been widely used to treat antipyretic, analgesic, anti-inflammation, abdominal pain, and fever in Taiwan. The aim of this study was to evaluate the antioxidant, antinociceptive, and anti-inflammatory lipopolysaccharide-(LPS-)induced nitric oxide (NO) production in RAW264.7 macrophages and pawedema induced by λ-carrageenan activities of the methanol extract from A. callosa. In HPLC analysis, the fingerprint chromatogram of ethyl-acetate fraction of A. callosa (EAAC) was established. EAAC showed the highest TEAC and DPPH radical scavenging activities, respectively. We evaluated that EAAC and the reference compound of catechin and caffeic acid decreased the LPS-induced NO production in RAW264.7 cells. Treatment of male ICR mice with EAAC significantly inhibited the numbers of acetic acid-induced writhing response and the formalin-induced pain in the late phase. Administration of EAAC showed a concentration-dependent inhibition on paw edema development after Carr treatment in mice. Anti-inflammatory mechanisms of EAAC might be correlated to the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) in vitro and in vivo. Overall, the results showed that EAAC demonstrated antioxidant, antinociceptive, and anti-inflammatory activity, which supports previous claims of the traditional use for inflammation and pain.

Innovative Hybrid-Alignment Annotation Method for Bioinformatics Identification and Functional Verification of a Novel Nitric Oxide Synthase in Trichomonas vaginalis.

Both the annotation and identification of genes in pathogenic parasites are still challenging. Although, as a survival factor, nitric oxide (NO) has been proven to be synthesized in Trichomonas vaginalis (TV), nitric oxide synthase (NOS) has not yet been annotated in the TV genome. We developed a witness-to-suspect strategy to identify incorrectly annotated genes in TV via the Smith-Waterman and Needleman-Wunsch algorithms through in-depth and repeated alignment of whole coding sequences of TV against thousands of sequences of known proteins from other organisms. A novel NOS of TV (TV NOS), which was annotated as hydrogenase in the NCBI database, was successfully identified; this TV NOS had a high witness-to-suspect ratio and contained all the NOS cofactor-binding motifs (NADPH, tetrahydrobiopterin (BH4), heme and flavin adenine dinucleotide (FAD) motifs). To confirm this identification, we performed in silico modeling of the protein structure and cofactor docking, cloned the gene, expressed and purified the protein, performed mass spectrometry analysis, and ultimately performed an assay to measure enzymatic activity. Our data showed that although the predicted structure of the TV NOS protein was not similar to the structure of NOSs of other species, all cofactor-binding motifs could interact with their ligands with high affinities. We clearly showed that the purified protein had high enzymatic activity for generating NO in vitro. This study provides an innovative approach to identify incorrectly annotated genes in TV and highlights a novel NOS that might serve as a virulence factor of TV.

A pentiptycene-derived molecular brake: photochemical E→Z and electrochemical Z→E switching of an enone module.

The synthesis and brakelike performance of a new molecular system (1) consisting of a pentiptycene rotor and a 2-methyleneindanone brake are reported. The rotation kinetics of the rotor was probed by both variable-temperature (1)H and (13)C NMR spectroscopy and DFT calculations, and the switching between the brake-on and brake-off states was conducted by a combination of photochemical and electrochemical isomerization. Because of the greater steric hindrance between the rotor and the brake units in the Z form ((Z)-1) than in the E form ((E)-1), rotation of the rotor is slowed down 500-fold at room temperature (298 K) on going from (E)-1 to (Z)-1, corresponding to the brake-off and brake-on states, respectively. The (E)-1→(Z)-1 photoisomerization in acetonitrile is efficient and reaches an (E)-1/(Z)-1 ratio of 11:89 in the photostationary state upon excitation at 290 nm, attributable to a much larger isomerization quantum efficiency for (E)-1 versus (Z)-1. An efficient (Z)-1→(E)-1 isomerization (96%) was also achieved by electrochemical treatment through the radical anionic intermediates. Consequently, the reversibility of the E-Z switching of 1 is as high as 85%. The repeated E-Z switching of 1 with alternating photochemical and electrochemical treatments is also demonstrated.

Toward a four-toothed molecular bevel gear with C2-symmetrical rotors.

The design, synthesis, conformational analysis, and variable-temperature NMR studies of pentiptycene-based molecular gears Pp(2)X, where Pp is the unlabeled (in 1H) or methoxy groups-labeled (in 1OM) pentiptycene rotor and X is the phenylene stator containing ortho-bridged ethynylene axles, are reported. The approach of using shape-persistent rotors of four teeth but C(2) symmetry for constructing four-toothed molecular gears is unprecedented. In addition, the first example of enantioresolution of chiral pentiptycene scaffolds is demonstrated. Density functional theory (DFT) and AM1 calculations on these Pp(2)X systems suggest two possible correlated torsional motions, geared rocking and four-toothed geared rotations, which compete with the uncorrelated gear slippage. The DFT-derived torsional barriers in 1H for rocking, four-toothed rotation, and gear slippage are approximately 2.9, 5.5, and 4.7 kcal mol(-1), respectively. The low energy barriers for these torsional motions result from the low energy cost of bending the ethynylene axles. Comparison of the NMR spectra of 1OM in a mixture of stereoisomers (1OM-mix) and in an enantiopure form (1OM-op) confirms a fast gear slippage in these Pp(2)X systems. The effect of the methoxy labels on rotational potential energy surface and inter-rotor dynamics is also discussed.

Analgesic and Anti-Inflammatory Activities of the Methanol Extract from Pogostemon cablin.

Pogostemon cablin (PC) is a herbal medicine traditionally applied to treat not only common cold, nausea and diarrhea but also headache and fever. The aim of this study was to investigate the analgesic and anti-inflammatory properties of standardized PC methanol extract (PCMeOH) in vivo. Investigations were performed in mice with two analgesic models. One was acetic acid-induced writhing response and the other formalin-induced paw licking. The anti-inflammatory effect was tested by λ-carrageenan (Carr)-induced mice paw edema. These analgesic experimental results indicated that PCMeOH (1.0 g/kg) decreased the acetic acid-induced writhing responses and PCMeOH (0.5 and 1.0 g/kg) decreased the licking time in the second phase of the formalin test. Moreover, Carr-induced paw edema inflammation was significantly reduced in a dose-dependent manner when PCMeOH (0.5 and 1.0 g/kg) was administered 3 and 4 h after the Carr injection. Mechanistic studies showed that PCMeOH decreased the levels of malondialdehyde in the edema paw by increasing the activities of anti-oxidant enzymes, such as superoxide dismutase, glutathione peroxidase and glutathione reductase, in the liver and decreasing the cyclooxygenase 2 and tumor necrosis factor-α activities in the edema paw. This study has demonstrated the analgesic and anti-inflammatory effects of PCMeOH, thus verifying its popular use in traditional medicine.

Antinociceptive activities and the mechanisms of anti-inflammation of asiatic Acid in mice.

Asiatic acid (AA), a pentacyclic triterpene compound in the medicinal plant Centella asiatica, was evaluated for antinociceptive and anti-inflammatory effects. Treatment of male ICR mice with AA significantly inhibited the numbers of acetic acid-induced writhing responses and the formalin-induced pain in the late phase. In the anti-inflammatory test, AA decreased the paw edema at the 4th and 5th h after λ-carrageenan (Carr) administration and increased the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in the liver tissue. AA decreased the nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-1ß (IL-1ß) levels on serum level at the 5th h after Carr injection. Western blotting revealed that AA decreased Carr-induced inducible nitric oxide synthase (iNOS), cyclooxygenase (COX-2), and nuclear factor-κB (NF-κB) expressions at the 5th h in the edema paw. An intraperitoneal (i.p.) injection treatment with AA also diminished neutrophil infiltration into sites of inflammation as did indomethacin (Indo). The anti-inflammatory mechanisms of AA might be related to the decrease in the level of MDA, iNOS, COX-2, and NF-κB in the edema paw via increasing the activities of CAT, SOD, and GPx in the liver.

Propofol-Based Total Intravenous Anesthesia is Associated with Better Survival than Desflurane Anesthesia in Epithelial Ovarian Cancer Surgery: A Retrospective Cohort Study.

Background: Previous studies have shown that anesthetic techniques can affect outcomes of cancer surgery. We investigated the association between anesthetic techniques and patient outcomes after elective epithelial ovarian cancer surgery. Methods: This was a retrospective cohort study of patients who received elective open surgery for epithelial ovarian cancer between January 2009 and December 2014. Patients were grouped according to the administration of propofol or desflurane anesthesia. Kaplan-Meier analysis was performed, and survival curves were constructed from the date of surgery to death. Univariate and multivariate Cox regression models were used to compare hazard ratios for death after propensity matching. Subgroup analyses were performed for age, body mass index, preoperative carbohydrate antigen-125 level, International Federation of Gynecology and Obstetrics staging, and operation and anesthesia time. Results: In total, 165 patients (76 deaths, 46.1%) who received desflurane anesthesia and 119 (30 deaths, 25.2%) who received propofol anesthesia were eligible for analysis. After propensity matching, 104 patients were included in each group. In the matched analysis, patients who received propofol anesthesia had better survival with a hazard ratio of 0.52 (95% confidence interval, 0.33-0.81; p = 0.005). Subgroup analyses also showed significantly better survival with old age, high body mass index, elevated carbohydrate antigen-125 level, advanced International Federation of Gynecology and Obstetrics stage, and prolonged operation and anesthesia time in the matched propofol group. In addition, patients administered with propofol anesthesia had less postoperative recurrence and metastasis than those administered with desflurane anesthesia in the matched analysis. Conclusion: Propofol anesthesia was associated with better survival in patients who underwent elective epithelial ovarian cancer open surgery. Prospective studies are warranted to evaluate the effects of propofol anesthesia on oncological outcomes in patients with epithelial ovarian cancer.

Phafin2 modulates the structure and function of endosomes by a Rab5-dependent mechanism.

By regulating the amount of protein receptors on the cell membrane and the metabolisms of receptor-bound ligands, endocytosis represents one of the fundamental biological activities that regulate how cells respond to the environment. We report here that a Fab1-YotB-Vac1p-EEA1 (FYVE) domain-containing lipid associated protein, called Phafin2, is preferentially expressed in the human hepatocellular carcinoma (HCC) and is involved in the biogenesis of endosomes. Over-expression of Phafin2 or its FYVE domain results in the formation of enlarged endosomes that are still functional for endocytosis; the biogenesis of such abnormal organelles is mediated by phosphoinositide 3-kinases (PI3K) and Rab5 signaling. Using fluorescence resonance energy transfer measured by fluorescence lifetime imaging microscopy (FLIM-FRET), we further demonstrate in live cells that Phafin2 can directly activate Rab5. By modulating the receptor internalization/recycling and Rab5 activation, Phafin2 affects the density of membranous insulin receptors, and regulates the transcriptional activity of AP-1 that is downstream of the insulin signaling pathway. These results provide a vivid example that an endosome modulator, such as Phafin2, may control the cells' responses to the extracellular cues.

Pentiptycene-derived light-driven molecular brakes: substituent effects of the brake component.

Five pentiptycene-derived stilbene systems (1 R; R = H, OM, NO, Pr, and Bu) have been prepared and investigated as light-driven molecular brakes that have different-sized brake components (1 H<1 OM<1 NO<1 Pr<1 Bu). At room temperature (298 K), rotation of the pentiptycene rotor is fast (k(rot)=10(8)-10(9)  s(-1)) with little interaction with the brake component in the trans form ((E)-1 R), which corresponds to the brake-off state. When the brake is turned on by photoisomerization to the cis form ((Z)-1 R), the pentiptycene rotation can be arrested on the NMR spectroscopic timescale at temperatures that depend on the brake component. In the cases of (Z)-1 NO, (Z)-1 Pr, and (Z)-1 Bu, the rotation is nearly blocked (k(rot)=2-6 s(-1)) at 298 K. It is also demonstrated that the rotation is slower in [D(6)]DMSO than in CD(2)Cl(2). A linear relationship between the free energies of the rotational barrier and the steric parameter A values is present only for (Z)-1 H, (Z)-1 OM, and (Z)-1 NO, and it levels off on going from (Z)-1 NO to (Z)-1 Pr and (Z)-1 Bu. DFT calculations provide insights into the substituent effects in the rotational ground and transition states. The molar reversibility of the E-Z photoswitching is up to 46%, and both the E and Z isomers are stable under the irradiation conditions.