Effects of heavy ions (12C6+) on malignant melanoma B16F10 cells.

Background: This study aimed to investigate the effects of heavy ion (12C6+) irradiation on the proliferation, apoptosis, cell cycle, migration, and epithelial-mesenchymal transition (EMT) of B16F10 cells. Methods: The B16F10 cells, which is a malignant melanoma cell line widely used in research, irradiated by 12C6+ and X-ray were detected by Hoechst 33342/propidium iodide double staining, Western blot, flow cytometry, and cell scratch tests to evaluate cell proliferation, expression of apoptosis-related proteins, G2/M phase arrest, cell migration, cell invasion and EMT. Results: Compared with the same physical X-ray dose, 12C6+ could effectively inhibit the proliferation of B16F10 cells, inhibit the expression of B-cell lymphoma-2 (Bcl-2) and cellular-myelocytomatosis viral oncogene (c-Myc), and induce the expression of Bax to promote the apoptosis of B16F10 cells. After 12C6+ irradiation, the B16F10 cells exhibited G2/M phase arrest. B16F10 cells were highly sensitive to 12C6+ irradiation. Moreover, compared with X-ray, the 12C6+ irradiation significantly inhibited the migration of B16F10 cells and inhibited extracellular matrix cleavage, induced E-cadherin expression, enhanced cell adhesion, and further inhibited cell invasion, migration, and EMT. Conclusions: The B16F10 cells were highly radiosensitive to 12C6+. Compared with X-ray, B16F10 cells irradiated by 12C6+ significantly reduced the expressions of matrix metalloproteinases to inhibit extracellular matrix cleavage and, thus, effectively inhibit cell invasion and metastasis. However, although the issue of the different therapeutic effects of heavy ion and X-ray radiotherapy on malignant melanoma was investigated and preliminary research results were obtained, several problems must be further studied.

[Altitudinal patterns of species richness and species range size of vascular plants in Xiaolong- shan Reserve of Qinling Mountain: a test of Rapoport' s rule].

Altitudinal patterns of species richness and species range size and their underlying mechanisms have long been a key topic in biogeography and biodiversity research. Rapoport's rule stated that the species richness gradually declined with the increasing altitude, while the species ranges became larger. Using altitude-distribution database from Xiaolongshan Reverse, this study explored the altitudinal patterns of vascular plant species richness and species range in Qinling Xiaolongshan Reserve, and examined the relationships between species richness and their distributional middle points in altitudinal bands for different fauna, taxonomic units and growth forms and tested the Rapoport's rule by using Stevens' method, Pagel's method, mid-point method and cross-species method. The results showed that the species richness of vascular plants except small-range species showed a unimodal pattern along the altitude in Qinling Xiaolongshan Reserve and the highest proportion of small-range species was found at the lower altitudinal bands and at the higher altitudinal bands. Due to different assemblages and examining methods, the relationships between species distributing range sizes and the altitudes were different. Increasing taxonomic units was easier to support Rapoport's rule, which was related to niche differences that the different taxonomic units occupied. The mean species range size of angiosperms showed a unimodal pattern along the altitude, while those of the gymnosperms and pteridophytes were unclearly regular. The mean species range size of the climbers was wider with the increasing altitude, while that of the shrubs which could adapt to different environmental situations was not sensitive to the change of altitude. Pagel's method was easier to support the Rapoport's rule, and then was Steven's method. On the contrary, due to the mid-domain effect, the results of the test by using the mid-point method showed that the mean species range size varied in a unimodal pattern along the altitude, which didn't support the Rapoport's rule, and because of the scatter-spot impact, the explanatory power of the cross-species method was much lower.

[Vertical patterns of plant species diversity in the Baishuijiang Nature Reserve: explanation of area, climate and boundary constraint].

The linear regression models and variation partitioning method were used to analyze the relative and pure effects of area, climate, and boundary constraint on altitudinal patterns of plant species diversity in the Baishuijiang Natural Reserve. The results showed that diversities of overall plant species and different group species exhibited humped-shaped patterns and the peaks were below the mid-point of the elevation span. The patterns were shaped by all factors together. The explanatory power of water-energy hypothesis for the pattern was the strongest. Area acted as a secondary factor the patterns. Boundary constraint effect was a complementary mechanism to explain the plant species diversity altitudinal patterns in Baishuijiang region. The explanatory powers of boundary constraint for different-range species were clearly different. With the increase of species range, boundary constraint showed an increasingly strong correlation with richness patterns.