Reprogramming induced by isoliquiritigenin diminishes melanoma cachexia through mTORC2-AKT-GSK3ß signaling.

Isoliquiritigenin (ISL), a member of the flavonoids, is known to have anti-tumor activity in vitro and in vivo. The effect of ISL on reprogramming in cancer cells, however, remains elusive. In this study, we investigated the effect of ISL on reprogramming in human melanoma A375 cells. ISL (15 µg/ml) significantly inhibited A375 cell proliferation, anchorage independent cell proliferation and G2/M cell cycle arrest after ISL exposure for 24 h. However, there were no significant changes in apoptosis rate. Terminal differentiation indicators (melanin content, melanogenesis mRNA expression, tyrosinase (TYR) activity) were all up-regulated by ISL treatment. In ISL-treated cells, glucose uptake, lactate levels and mRNA expression levels of GLUT1 and HK2 were significantly decreased, and accompanied by an increase in O2 consumption rate (OCR) and adenosine triphosphate (ATP) deficiency. Protein expression levels of mTORC2-AKT-GSK3ß signaling pathway components (mTOR, p-mTOR, RICTOR, p-AKT, p-GSK3ß) decreased significantly after ISL treatment. Co-treatment of ISL and the mTOR-specific inhibitor Ku-0063794 had a synergistic effect on the inhibition of proliferation, and increased melanin content and TYR activity. Glucose uptake and lactate levels decreased more significantly than treatment with ISL alone. These findings indicate that ISL induced reprogramming in A375 melanoma cells by activating mTORC2-AKT-GSK3ß signaling.

Nectar properties and the role of sunbirds as pollinators of the golden-flowered tea (Camellia petelotii).

PREMISE OF THE STUDY: Properties of floral nectar have been used to predict if a plant species is pollinated by birds. To see whether winter-flowering plants evolve nectar properties corresponding to bird pollinators, nectar properties of several Camellia species (including the golden-flowered tea), as well as the role of floral visitors as effective pollinators, were examined. METHODS: Potential pollinators of Camellia petelotii were identified at different times of day and under various weather conditions. A bird exclusion experiment was used to compare the pollination effectiveness of birds and insects. Nectar sugar components (fructose, glucose, and sucrose) from C. petelotii growing wild and another seven Camellia species and 22 additional cultivars (all in cultivation) were examined by high-performance liquid chromatography (HPLC). KEY RESULTS: The sunbird Aethopyga siparaja and honeybees were the most frequent floral visitors to C. petelotii. Honeybee visits were significantly reduced in cloudy/rainy weather. The fruit and seed set of flowers with birds excluded were reduced by 64%, indicating that bird pollination is significant. For the wild populations of C. petelotii, a bagged flower could secrete 157 µL nectar; this nectar has a low sugar concentration (19%) and is sucrose-dominant (87%). The eight Camellia species and 22 cultivars had an average sugar concentration of around 30% and a sucrose concentration of 80%, demonstrating sucrose-dominant nectar in Camellia species. CONCLUSIONS: The nectar sugar composition of Camellia species was characterized by sucrose dominance. In addition, the large reduction in seed set when birds are excluded in the golden-flowered tea also supports the suggestion that these winter-flowering plants may have evolved with birds as significant pollinators.

Geographic consistency and variation in conflicting selection generated by pollinators and seed predators.

BACKGROUNDS AND AIMS: Floral traits that attract pollinators may also attract seed predators, which, in turn, may generate conflicting natural selection on such traits. Although such selection trade-offs are expected to vary geographically, few studies have investigated selection mediated by pollinators and seed predators across a geographic mosaic of environments and floral variation. METHODS: Floral traits were investigated in 14 populations of the bumble-bee-pollinated herb, Pedicularis rex, in which tubular flowers are subtended by cupular bracts holding rain water. To study potentially conflicting selection on floral traits generated by pollinators and florivores, stigmatic pollen loads, initial seed set, pre-dispersal seed predation and final viable seed production were measured in 12-14 populations in the field. KEY RESULTS: Generalized Linear Model (GLM) analyses indicated that the pollen load on stigmas was positively related to the exsertion of the corolla beyond the cupular bracts and size of the lower corolla lip, but so too was the rate of seed predation, creating conflicting selection on both floral traits. A geographic mosaic of selection mediated by seed predators, but not pollinators, was indicated by significant variation in levels of seed predation and the inclusion of two-, three- and four-way interaction terms between population and seed predation in the best model [lowest corrected Akaike Information Criterion (AICc)] explaining final seed production. CONCLUSIONS: These results indicate opposing selection in operation: pollinators generated selection for greater floral exsertion beyond the bracts, but seed predators generated selection for reduced exsertion above the protective pools of water, although the strength of the latter varied across populations.

A highly selective near-infrared fluorescent probe for carboxylesterase 2 and its bioimaging applications in living cells and animals.

A near-infrared fluorescent probe (DDAB) for highly selective and sensitive detection of carboxylesterase 2 (CE2) has been designed, synthesized, and systematically studied both in vitro and in vivo. Upon addition of CE2, the ester bond of DDAB could be rapidly cleaved and then release a near-infrared (NIR) fluorophore DDAO, which brings a remarkable yellow-to-blue color change and strong NIR fluorescence emission in physiological solutions. The newly developed probe exhibits excellent properties including good specificity, ultrahigh sensitivity and high imaging resolution. Moreover, DDAB has been applied to measure the real activities of CE2 in complex biological samples, as well as to screen CE2 inhibitors by using tissue preparations as the enzymes sources. The probe has also been successfully used to detect endogenous CE2 in living cells and in vivo for the first time, and the results demonstrate that such detection is highly reliable. All these prominent features of DDAB make it holds great promise for further investigation on CE2-associated biological process and for exploring the physiological functions of CE2 in living systems.

Pollen size strongly correlates with stigma depth among Pedicularis species.

Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the style heterotrophically. However, studies often show a positive relationship between pollen size and style length. Five floral traits were observed to be correlated among 42 bumblebee-pollinated Pedicularis species (Orobanchaceae) in which stigmas are distinct from styles. The phylogenetic independent contrast analysis revealed that pollen grain volume was more strongly correlated with stigma depth than with style length, consistent with Darwin's functional hypothesis between pollen size and stigma depth.

Are long corolla tubes in Pedicularis driven by pollinator selection?

The evolution of long corolla tubes has been hypothesized to be driven by long-tongued pollinators. Corolla tubes in Pedicularis species can be longer than 10 cm which may function as flower stalks to increase visual attractiveness to pollinators because these species provide no nectar and are pollinated by bumblebees. The corolla tube length was manipulated (shorter or longer) in two Pedicularis species in field to examine whether longer tubes are more attractive to pollinators and produce more seeds than short tubes. Our results did not support the pollinator attraction hypothesis, leaving the evolution of long tubes in Pedicularis remains mysterious.

Rainwater in cupulate bracts repels seed herbivores in a bumblebee-pollinated subalpine flower.

Floral herbivory may have deleterious effects on the reproductive success of flowering plants. However, plants may evolve floral traits that allow them to defend against herbivory in particular conditions. A bumblebee-pollinated subalpine herb, Pedicularis rex (Orobanchaceae), endemic to southwest China, has cup-like bracts that fill with rainwater, which submerges its corolla tubes. We hypothesized that these water-filled cupulate bracts function to deter nectar robbers and/or seed herbivores. To test these hypotheses, we experimentally drained bracts and measured both the response of mutualistic floral visitors and antagonistic nectar robbers and seed predators and their effects on seed production. Our observations revealed that neither nectar robbers nor legitimate pollinators discriminated between water-drained flowers and intact controls. However, seed predation significantly increased in drained flowers, suggesting that water-filled bracts help protect the flowers from seed herbivores. The water-filled bracts in P. rex may represent an adaptation to reduce floral herbivory in a high-rainfall environment.

Rhodamine-based 'turn-on' fluorescent probe for Cu(II) and its fluorescence imaging in living cells.

A novel rhodamine spirolactam derivative 3',6'-Bis(diethylamino)-2-(2-hydroxyethylamino) spiro[isoindoline-1,9'-xanthen]-3-one (RO1) was synthesized, and characterized by high-resolution mass spectrometry (HRMS), X-ray crystallography, Infrared spectroscopy (IR), and (1)H NMR and (13)C NMR spectroscopy. RO1 exhibited highly sensitive and exclusively selective fluorescence response toward Cu(2+) over other metal ions with a detection limit of 0.56ppb in mixed aqueous solution. The fluorescence was pH-independent in the wide range pH 3.1-11.6. The turn-on fluorescence enhancement of the probe is based on Cu(2+) induced ring-opening mechanism of the rhodamine spirolactam. Moreover, by means of fluorescence microscopy experiments, it was demonstrated that RO1 could monitor trace Cu(2+) changes by live cell imaging.

Experimental and theoretical study of the exited state of aminostyryl terpyridine derivatives: hydrogen-bonding effects.

The synthesis, structure and photophysical behavior of the aminostyryl terpyridine derivatives, named 4'-(4-{2-[4-(N,N-dimethylaniline)]vinyl}phenyl)-2,2':6',2″-terpyridine (M(1)) and the related model compounds 4'-(4-{2-[4-(N,N-diphenylammino)phenyl]vinyl}phenyl)-2,2':6',2″-terpyridine (M(2)), respectively, are reported. Large solvatochromic shifts of the first excited-state fluorescence maximum suggest the intramolecular charge transfer characters for both compounds. In addition, with N,N-dimethyl substituents, its fluorescence is quenched a lot in protic solvents. This is consisted with the decay of its S(1) state, through nonradiative internal conversion, to the ground state, which is facilitated by the formation of the hydrogen bond between M(1) and alcohols. Whereas, the introduction of N,N-diphenyl substituents has been proved to be a hydrogen-bond-free case with the unchanged Φ(f). Furthermore, the formation of TICT state via diffusive twisting motion of the dimethyl/phenylamino group is the major relaxation process, which is proved by the ultrafast relaxation dynamics experiment and theoretically conformational optimization of the first excited-state of both the compounds.

Theoretical and experimental study on the intramolecular charge transfer excited state of the new highly fluorescent terpyridine compound.

Experimental and theoretical methods have been used to investigate the relaxation dynamics and photophysical properties of the donor-acceptor compound 4'-(4-N,N-diphenylaminophenyl)-2,2':6',2''-terpyridine (DPAPT), a compound which is found to exhibit efficient intramolecular charge transfer emission in polar solvents with relatively large Stokes shifts and strong solvatochromism. The difference between the ground and excited state dipole moments (Deltamu) is estimated to be 13.7D on the basis of Lippert-Mataga models. To gain insight into the relaxation dynamics of DPAPT in the excited state, the potential energy curves for conformational relaxation are calculated. From the frontier molecular orbital (MO) pictures at the geometry of the twisted ICT excited state, the intramolecular charger transfer mainly takes place from HOMO (triphenylamine) to LUMO (terpyridine) in this donor-acceptor system.

mu-Oxo-bis{[(6-hydroxymethyl-2-pyridylmethyl)bis(2-pyridylmethyl)amine-kappa)N,N',N'',N''',O]iron(III)} tetrakis(perchlorate).

The novel mu-oxo-diiron complex [Fe2O(BPHPA)2](ClO4)4 [BPHPA is (6-hydroxymethyl-2-pyridylmethyl)bis(2-pyridylmethyl)amine, C19H20N4O], contains a binuclear centrosymmetric [Fe2O(BPHPA)2]4+ cation (the bridging O atom lies on an inversion centre) and four perchlorate anions. Each iron ion is coordinated by four N atoms [Fe-N = 2.117 (5)-2.196 (5) A] and one O atom [Fe-O = 2.052 (5) A] from a BPHPA ligand, and by one bridging oxo atom [Fe-O = 1.7896 (9) A], forming a distorted octahedron. There are hydrogen bonds between the hydroxy group and perchlorate O atoms [O-H...O = 2.654 (7) A].

Gender variation of sequential inflorescences in a monoecious plant Sagittaria trifolia (Alismataceae).

In protogynous plants, female flowers of early blooming plants are at a reproductive disadvantage because they cannot set fruit due to the lack of available pollen. To study this phenomenon, gender expression of the monoecious herb Sagittaria trifolia was investigated over the entire flowering season in two field and two cultivated populations in Hubei and Hunan Provinces, China. In racemes of S. trifolia, flowers open sequentially from bottom to top, with female flowers opening first followed by male flowers. This creates a temporal separation of sexes in the species. Under field conditions small plants are often male, with production of both male and female flowers increasing with plant size. Femaleness increased among sequential inflorescences since female flower production increased whereas male flower production did not. Seed production was greater in large inflorescences because they contain more female flowers, and the number of ovules increased in female flowers at basal positions within the raceme. A consistent pattern of high seed set was observed in flowers from both field and cultivated populations. About 1 % of unfertilized ovules resulted from no pollination and 2 % of the seeds produced were only partly developed due to resource limitation. In the first inflorescence of the six experimental populations, 6.7-40.0 % of individuals produced only male flowers, and female flowers of 1.9-6.5 % individuals were aborted. The occurrence of male flowers in early blooming inflorescences could be an adaptive strategy to conserve resources and enhance pollination of female flowers in protogynous S. trifolia.