A Selective Fluorescent Probe for the Determination and Imaging of Fluoride in Living Cells

Abstract Fluoride anions are indispensable trace elements required for sustaining life. To investigate the homeostasis and action of fluoride in the body, a new highly sensitive and selective fluorescence detection method was designed for fluoride in aqueous solutions. A fluorescent probe for fluoride (FP-F) was synthesized for imaging F- in living cells. The design strategy for the probe was based on the specific reaction between fluoride and silica to mediate deprotection of this probe to fluorescein. Upon treatment with F-, FP-F, a closed and weakly fluorescent lactone, was transformed into an open and strongly fluorescent product. Under the optimum conditions, the detection limit for fluoride was 0.526 nM. FP-F could detect micromolar changes in F- concentrations in living cells by confocal microscopy.

The complete chloroplast genome sequence of Sargentodoxa cuneata: genome structure and genomic resources.

Sargentodoxa cuneata is used as traditional Chinese medicine. In this study, we report its complete chloroplast genome by Illumina pair-end sequencing. The total chloroplast (cp) genome size was 158,094 bp in length, containing a pair of inverted repeats of 26,132 bp, separated by large single-copy and small single-copy regions of 86,508 bp and 19,322 bp, respectively. The chloroplast genome of S. cuneata encodes 113 different genes, including 79 protein-coding genes, 30 transfer RNAs, and 4 ribosomal RNAs. A total of 84 perfect chloroplast microsatellites were analyzed in the S. cuneata. The majority of the SSRs in this chloroplast genome are mononucleotides (66.67%). The reconstructed phylogeny revealed that S. cuneata was sister to the remaining Lardizabalaceae.

Astragaloside IV inhibits cell proliferation of colorectal cancer cell lines through down-regulation of B7-H3.

Astragaloside IV showed a pivotal anti-cancer efficacy in multiple types of cancers and reversed chemoresistance in colorectal cancer (CRC). However, it remained unknown whether and how Astragaloside IV suppressed the progression of CRC. In the present study, we found that Astragaloside IV treatment significantly and dose-dependently reduced cell proliferation of CRC cell lines (SW620 and HCT116), whereas it showed no significant influence on the cell proliferation of normal colonic cells (FHC). Flow cytometry (FCM) analysis indicated that there was a significant cell cycle arrest in G0/G1 phase of SW620 cells and HCT116 cells which were treated with Astragaloside IV. The mRNA levels and protein levels of several key cell cycle relative proteins (cyclin D1 and CDK4) were also dramatically decreased during the process of G0/G1 arrest after the administration of Astragaloside IV. In addition, we observed an obvious decrease of B7-H3 protein level upon Astragaloside IV treatment, which was a result of mRNA reduction that was verified by real-time quantitative polymerase chain reaction (RT-qPCR) and CHX chase. We further identified that Astragaloside IV suppressed B7-H3 expression by elevating the expression of miR-29c level. Inhibition of miR-29c could dramatically reverse Astragaloside IV-induced B7-H3 decrease and cell growth arrest. This study suggests that Astragaloside IV is a promising anti-cancer drug in CRC.

MicroRNA-197 inhibits cell proliferation by targeting GAB2 in glioblastoma.

Glioblastoma is the most common type of primary brain tumor in adults, and is usually fatal in a short duration. Acquiring a better understanding of the pathogenic mechanisms of glioblastoma is essential to the design of effective therapeutic strategies. Grb2-associated binding protein 2 (GAB2) is a member of the daughter of sevenless/Gab family of scaffolding adapters, and has been reported to be important in the development and progression of human cancer. Previously, it has been reported that GAB2 is expressed at high levels in glioma, and may serve as a useful prognostic marker for glioma and a novel therapeutic target for glioma invasion intervention. Elucidating why GAB2 is overexpressed in glioma, and investigating how to downregulate it will assist in further understanding the pathogenesis and progression of the disease, and to offer novel targets for therapy. The present study used in situ hybridization to detect microRNA (miR)­197 expression levels and Targetscan to predict that the 3'-UTR of GAB2 was targeted by miR-197. Northern blotting and reverse transcription­quantitative polymerase chain reaction were also conducted in the current study. miR-197 is downregulated in glioblastoma tissues, compared with adjacent normal tissues, however it involvement continues to be detected in the disease. The results of the present study demonstrated that miR­197, as a tumor suppressor gene, inhibited proliferation by regulating GAB2 in glioblastoma cells. Furthermore, GAB2 was not only upregulated in glioma, but its expression levels were also associated with the grades of glioma severity. In addition, overexpression of GAB2 suppressed the expression of miR­197 in glioblastoma cells. Therefore, restoration of miR­197 and targeting GAB2 may be used, in conjunction with other therapies, to prevent the progression of glioblastoma.

[Gaps and their natural disturbance characteristics in mid-subtropical evergreen broad-leaved forest in Wanmulin].

Through field investigation on 96 gaps in some permanent plots of mid-subtropical evergreen broad-leaved forest in Wanmulin Natural Reserve of Fujian Province, this paper dealt with the gap characteristics and their natural disturbance. The results showed that the area percentage of expanded gap (EG) and canopy gap (CG) in the forest landscape was 50.86% and 16.66%, and the natural disturbance frequency for EG and CG was 0.85% x yr(-1) and 0.28% x yr(-1), respectively. The return interval of canopy gaps was about 357 years. The most popular manner of gap formation in the forest was stem breakage (58.04% of the total), and the second was uprooting (33.48%). Most gaps were formed by two trees, averaging 2.33 trees per gap. The size of most expanded gaps was in the range of 100 - 300m2, the gaps of 200 - 300m2 occupied the biggest percentage in area, and those of 100 - 200m2 occupied the biggest percentage in number. The size of most canopy gaps was under 100m2, and the gaps of < 50m2 had the biggest percentage in area and number. The diameter at breast height of most gap makers was 20 - 30cm.

[Life table and spectral analysis of endangered plant Taxus chinensis var. mairei population].

Based on the investigation in Longxi Mountain National Nature Reserve and the theory of survival analysis, a static life table of Taxus chinensis var. mairei population was worked out, the curves of its survival rate, mortality rate and killing power were drawn, and the population dynamics was analyzed by spectral analysis. The results showed that the survival curve of the population appeared to be a type of Deevey-III, and the high mortality of seeding was one of the important reasons which caused Taxus chinensis var. mairei to be endangered. The spectral analysis of the population showed that there was a marked periodic regularity in the process of natural regeneration of Taxus chinensis var. mairei.

[Height structures of dominant species of different subtropical evergreen broadleaved forest communities in Wanmulin Natural Reserve].

Based on the data of four subtropical evergreen broadleaved forest communities in Wanmulin Natural Reserve, whose dominant species were Tsoongiodendron odorum Chun, Cinnamomum micranthum Hayata, Castanopsis fabri Hance and Pinus massoniana, respectively, the height class and diameter class structures and the dynamics of height structure were analyzed. The results showed that the relationships between tree species, tree density, basal area at D. B. H, and height class (or diameter class) could be simulated by different equations. There was a significant positive correlation between tree species and tree density for different height class or different D. B. H. class. The structure dynamic analysis showed that the community of Tsoongiodendron odorum Chun was very unstable, and the species sharing degree in four communities was fairly lower, indicating that the dominant species were very obvious. The results could give a useful clue for the studies on endangered mechanism of rare species.