Cyclodextrin-Confined Supramolecular Lanthanide Photoswitch.

The utilization of azobenzene-based photoisomerization cannot only control the morphology of supramolecular assemblies, but can also regulate many biological processes. However, the design of azobenzene-involved nanoconstructs with switchable photoluminescence remains challenging because of the light-quenching ability of azobenzene. Herein, an azobenzene-derived multicomponent nanosystem is reported and its function as a supramolecular lanthanide photoswitch is explored. The metal chelation between lanthanide ions (Ln3+  = Eu3+ and Tb3+ ) and 2,6-pyridinedicarboxylic acid is utilized as the light-emitting center but its inherent fluorescence emission is completely suppressed via the disordered motion of the adjoining azophenyl unit. Interestingly, the hydrophobic cavity of α-cyclodextrin can provide a confined microenvironment to immobilize the molecular conformation of trans-azobenzene, thus leading to the recovery of characteristic lanthanide luminescence both in aqueous solution and the hydrogel state. Also, the luminescence can be reversibly turned off when the cis-azobenzene is expelled from the cavity of α-cyclodextrin upon alternating light irradiation. This mutual cooperation arising from host-guest complexation and metal-ligand coordination confers the desired photoswitchable luminescence abilities on the commonly used azobenzenes, which may hold great promise in the creation of more advanced light-responsive smart materials.

Highly efficient photocontrolled targeted delivery of siRNA by a cyclodextrin-based supramolecular nanoassembly.

In this study, we have constructed a binary supramolecular nanoassembly composed of α-cyclodextrin-modified hyaluronic acid and an azobenzene-modified diphenylalanine derivative with a positively charged imidazole group. This nanoassembly can bind with siRNA through electrostatic interactions and efficiently delivered them into cancer cells and inhibited their growth.

A cucurbituril/polysaccharide/carbazole ternary supramolecular assembly for targeted cell imaging.

A carbazole derivative (G) was synthesized as a photosensitizer to complex with cucurbit[8]uril, resulting in a nanocube with emission at 662 nm for lysosome cell imaging. Furthermore, the alkyl chain on G was included by α-cyclodextrine-modified hyaluronic acid for further assembly, affording a system targeted to cancer cells.

Comprehensive analysis of the whole coding and non-coding RNA transcriptome expression profiles and construction of the circRNA-lncRNA co-regulated ceRNA network in laryngeal squamous cell carcinoma.

Recently, accumulating evidence has demonstrated that non-coding RNAs (ncRNAs) play a vital role in oncogenicity. Nevertheless, the regulatory mechanisms and functions remain poorly understood, especially for lncRNAs and circRNAs. In this study, we simultaneously detected, for the first time, the expression profiles of the whole transcriptome, including miRNA, circRNA and lncRNA + mRNA, in five pairs of laryngeal squamous cell carcinoma (LSCC) and matched non-carcinoma tissues by microarrays. Five miRNAs, four circRNAs, three lncRNAs and five mRNAs that were dysregulated were selected to confirm the verification of the microarray data by quantitative real-time PCR (qRT-PCR) in 20 pairs of LSCC samples. We constructed LSCC-related competing endogenous RNA (ceRNA) networks of lncRNAs and circRNAs (circRNA or lncRNA-miRNA-mRNA) respectively. Functional annotation revealed the lncRNA-mediated ceRNA network were enriched for genes involved in the tumor-associated pathways. Hsa_circ_0033988 with the highest degree in the circRNA-mediated ceRNA network was associated with fatty acid degradation, which was responsible for the depletion of fat in tumor-associated cachexia. Finally, to clarify the ncRNA co-regulation mechanism, we constructed a circRNA-lncRNA co-regulated network by integrating the above two networks and identified 9 modules for further study. A subnetwork of module 2 with the most dysregulated microRNAs was extracted to establish the ncRNA-involved TGF-ß-associated pathway. In conclusion, our findings provide a high-throughput microarray data of the coding and non-coding RNAs and establish the foundation for further functional research on the ceRNA regulatory mechanism of non-coding RNAs in LSCC.

The Increase of Flavonoids in Pericarpium Citri Reticulatae (PCR) Induced by Fungi Promotes the Increase of Antioxidant Activity.

There are thousands of traditional Chinese medicines in China, and they all have to be stored for a period of time for the reason of market price or other factors. But some traditional Chinese medicines especially need to be stored longer, and the clinical efficacy will be better. The cause and mechanism of this phenomenon have attracted much attention in recent years. In this study, we analyze the reason of "the longer storage period the better" of Pericarpium Citri Reticulatae (PCR); method of microscopic and molecular identification was used to identify the fungi separated and purified from PCR. The HPLC and UV spectrophotometry methods were used to determine the contents of flavonoids in PCR. The isolated fungi were inoculated into sterile samples to screen the fungi closely related to the change of flavonoids. The results indicate that the strain of Aspergillus niger could obviously promote the contents of flavonoids, and it could also increase the antioxidant effect of PCR. In conclusion, this study explains the reason of "the longer storage period the better" of PCR from the perspective of microbe, proving the beneficial effect of microorganism on the surface of PCR.

Differentiated miRNA expression and validation of signaling pathways in apoE gene knockout mice by cross-verification microarray platform.

The microRNA (miRNA) regulation mechanisms associated with atherosclerosis are largely undocumented. Specific selection and efficient validation of miRNA regulation pathways involved in atherosclerosis development may be better assessed by contemporary microarray platforms applying cross-verification methodology. A screening platform was established using both miRNA and genomic microarrays. Microarray analysis was then simultaneously performed on pooled atherosclerotic aortic tissues from 10 Apolipoprotein E (apoE) knockout mice (apoE-/-) and 10 healthy C57BL/6 (B6) mice. Differentiated miRNAs were screened and cross-verified against an mRNA screen database to explore integrative mRNA-miRNA regulation. Gene set enrichment analysis was conducted to describe the potential pathways regulated by these mRNA-miRNA interactions. High-throughput data analysis of miRNA and genomic microarrays of knockout and healthy control mice revealed 75 differentially expressed miRNAs in apoE-/- mice at a threshold value of 2. The six miRNAs with the greatest differentiation expression were confirmed by real-time quantitative reverse-transcription PCR (qRT-PCR) in atherosclerotic tissues. Significantly enriched pathways, such as the type 2 diabetes mellitus pathway, were observed by a gene-set enrichment analysis. The enriched molecular pathways were confirmed through qRT-PCR evaluation by observing the presence of suppressor of cytokine signaling 3 (SOCS3) and SOCS3-related miRNAs, miR-30a, miR-30e and miR-19b. Cross-verified high-throughput microarrays are optimally accurate and effective screening methods for miRNA regulation profiles associated with atherosclerosis. The identified SOCS3 pathway is a potentially valuable target for future development of targeted miRNA therapies to control atherosclerosis development and progression.

Synthesis and antitumor activity evaluation of new asiatic acid derivatives.

Twelve novel asiatic acid (AA) derivatives were designed and synthesized. Their structures were confirmed using NMR, MS, and IR spectra. Their in vitro cytotoxicities on various cancer cell lines (HeLa, HepG2, BGC-823, and SKOV3) were evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Most of the derivatives were found to have stronger cell growth inhibitory activity than AA. Among them, compounds 5-8 and 11 with substituted amide group at C-28 exhibited more potent cytotoxicity than AA, Gefitinib, and etoposide (positive control).

[Impacts of large hydropower station on benthic algal communities].

To investigate the impacts of large hydropower station in Gufu River on benthic algae, monthly samplings were conducted from September 2004 to June 2007 at the site GF04 which was impacted by the hydropower station, with the site GL03 in Gaolan River as reference. During sampling period, no significant differences were observed in the main physicochemical variables between GF04 and GL03, but the hydrodynamics differed significantly. GL03 was basically at a status of slow flow; while GF04, owing to the discharging from the reservoir, was at a riffle status during more than 60% of the sampling period. Such a difference in hydrodynamics induced significant differences in the community similarity of benthic algae and the relative abundance of unattached diatoms, erect diatoms, and stalked diatoms between GF04 and GL03, which could better reflect the impacts of irregular draw-off by large hydropower station on river eco-system.

[Seasonal dynamics of macrozoobenthos community structure in Xiangxi River].

To study the seasonal dynamics of macrozoobenthos community in Xiangxi River, the individuals of macrozoobenthos in the River were quantitatively monitored. A total of 197 taxa belonging to 6 class and 68 families were collected, among which, Baetis spp., Epeorus spp., and Nemoura spp. were the dominant groups, and their compositions varied with seasons. The macrozoobenthos community was most complicated in winter, followed by in spring and autumn, and the simplest in summer. Gather-collector was the main component of functional feeding groups in Xiangxi River system, followed by scraper, predator, and filter-collector, while shredder only accounted for a small part. Canonical correspondence analysis showed that the factors affecting the macrozoobenthos community were dissimilar among seasons. In summer and autumn, nutrients had greater effects; and in all seasons, water depth had definite effects.

Site-specific fluorescent labeling approaches for naringenin, an essential flavonone in plant nitrogen-fixation signaling pathways.

In search of an appropriate position for the fluorescent labeling, six chemically available positions of the flavonone core of naringenin have been examined. A number of azido-containing naringenin derivatives were accordingly prepared in various site-specific fashions, and the mild Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition successfully served as the common "Click" labeling tool in the final steps. On the basis of the biological activities of the first batch of labeled compounds, further optimization at the C-6 position of naringenin finally afforded naringenin-flu (27), which acquired 20% of the potency of naringenin and presented good optical properties. Entry of naringenin-flu into living Rhizobium cells was demonstrated by in vitro fluorescent imaging experiments.

[Spatial distribution of macroinvertebrates in Xiangxi River].

An investigation was made from July 2005 to June 2006 to understand the spatial distribution of macroinvertebrates in Xiangxi River, the largest tributary in Hubei portion of Three Gorges Reservoir. The results showed that Ephemeroptera baetis spp., Ephemeroptera epeorus spp., and Plecoptera nemoura spp. were the dominant taxa. There existed greater differences in the habitat characters and in the community structure of macroinvertebrates among the major tributaries of Xiangxi River, and the relative abundance of functional feeding groups could reflect the characters of different habitats. A comparison of the diversity of dominant taxa and their tolerance towards pollution among the major tributaries showed that Jiuchong River had the best habitat, followed by the main stream of Xiangxi River, and Gaolan River and Gufu River. Canonical correspondence analysis showed that the NH4+ -N concentration in the main stream of Xiangxi River, the pH, turbidity, water depth, SiO2, conductance, and alkalinity in Jiuchong River, the turbidity in Gaolan River, and the NH4+ -N and NO3- -N concentrations in Gufu River had significant impact on the community structure of macroinvertebrates.

N'-Benzoyl-3-hydr-oxy-2-naphthohydrazide.

In the title compound, C(18)H(14)N(2)O(3), the dihedral angle between the planes of the naphthalene and phenyl ring systems is 2.64 (2)°. Mol-ecules are engaged in π-π stacking (mean interplanar distance = 3.339 between naphthalene rings and 3.357 Šbetween benzene rings )and hydrogen-bonding inter-actions.

[Influence of cascaded exploitation of small hydropower on phytoplankton in Xiangxi River].

With the five small hydropowers (SHPs) from up- to downstream of Xiangxi River as test objects, this paper studied the influence of SHPs cascaded exploitation on the phytoplankton in the river. The results showed that phytoplankton assemblages were dominated by diatoms, occupying 95.54% of the total number of species. Achnanthes linearis, A. lanceolata var. elliptica and Cocconeis placentula were the most abundant species, with the relative abundance being 23.96%, 18.62% and 12.48%, respectively. The average algal density at 25 sampling sites was 6.29 x 10(5) ind x L(-1), with the maximum of 1.81 x 10(6) ind x L(-1) and the minimum of 2.35 x 10(5) ind x L(-1). Two-way ANOVA indicated that water flow velocity was the main factor affecting the phytoplankton. The establishment of the cascaded SHPs on the river made the habitat of lower reach has a significant difference with the others, resulting in a dramatic change of many parameters including Margalef diversity index, species richness, generic richness, taxonomic composition, and the percentage of diatoms.

Modulating DNA bending affects NodD-mediated transcriptional control in Rhizobium leguminosarum.

Rhizobium leguminosarum NodD binds to the nod box of the inducible nod gene nodA as a V-shaped tetramer and bends the nod box. In this work, we show that the nod gene inducer naringenin decreased gel mobility of nod box DNA-NodD complexes by sharpening the NodD-induced DNA bend, which correlated with nodA transcription activation. NodD can induce different DNA bends when the distance between the two half-sites of the nod box was modified, which severely affected NodD-mediated transcriptional control. One or two base pairs were deleted from, or inserted into, the two half-sites of the nod box of nodA. Circular permutation assays showed that such distance modulations allowed NodD to induce relaxed or sharpened DNA bending. In the case of 1 bp deletion, where the DNA bends were more relaxed than in the wild type, nodA transcription was repressed both in the absence and in the presence of inducer naringenin. In the cases of 1 and 2 bp insertion, where the DNA bends were much sharper than in wild type in the absence or presence of the inducer naringenin, nodA transcription was initiated constitutively with no requirement for the inducer naringenin or, even, the NodD regulating protein.

A HU-like gene mutation in Rhizobium leguminosarum bv. viciae affects the expression of nodulation genes.

NodD is the major regulator of nod genes expression in rhizobia. Previously, a HU-like protein in Rhizobium leguminosarum bv. viciae has been identified to bind specifically with nod promoters and be involved in in vitro nodD transcription, but its in vivo function remained unknown. In this work we have cloned and sequenced the R. leguminosarum bv. viciae gene, named hurL, for this HU-like protein. Using the E. coli-expressed HurL proteins, we proved that HurL had high affinity to several nod promoters and showed a stimulation effect on in vitro nodD transcription at appropriate concentration. The R. leguminosarum bv. viciae hurL gene was mutated by insertion of a kanamycin resistance cassette. The obtained hurL mutant strain M704 exhibited poor growth under free-living conditions and failed to induce nodules on Pisum sativum cv. Frisson and Vicia hirsuta. Further studies of NodD production and nod genes-lacZ fusions expression in the hurL mutant revealed that inactivation of hurL led to severe impairment in the nodD expression, repression in the inducible expression of nodA and nodF, and slight enhancement in the expression of px2, a gene identified earlier in this lab. These results suggested that hurL might be required for maintaining the normal expression of nod genes in R. leguminosarum bv. viciae.