Osteosarcoma (OS), a severe malignant bone tumour, usually occurs in adolescents and children and has a poor prognosis. Asiatic acid (AA), an active component isolated from Centella asiatica (L.) Urb., exhibits appreciable anti-oxidant and anti-tumour activities. So far, the effects and underlying mechanisms of AA against OS have not been clarified. Here, we explored the anti-tumour effects of AA against human OS and the involved mechanism mediating its actions. To evaluate effects of AA on the cell proliferation of human OS cells, cell viability and colony formation assays were performed. Flow cytometry was used to evaluate apoptosis in OS cells exposed to AA and mitochondrial membrane potential. Western blotting and RT-PCR were applied to determine expression of the relevant proteins and their mRNA levels. Our explorations showed that AA inhibits proliferation of human OS cells in a concentration- and time-dependent manner, and induces apoptosis of OS cells by the intrinsic (mitochondrial) pathway. Importantly, we found that inhibition of the AA-induced phosphorylation of JAK2/STAT3 signalling molecules and the decrease in MCL-1 contributed to the anti-tumour efficacy of AA. Collectively, our results suggest that AA could evoke mitochondrial- induced apoptosis in human OS cells by suppression of the JAK2/STAT3 pathway and MCL-1 expression. These results strongly demonstrate that AA could be a potential anti-tumour agent for OS treatment.
Photosynthesis and growth characteristics of Parthenocissus quinquefolia were measured under differing soil water availability within a pot. Decreased soil moisture significantly reduced the leaf relative water content (RWC) and the above- and below-ground biomass. However, more biomass was allocated to the root than to the leaf. Net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were also significantly decreased but water use efficiency (WUE) was increased. Midday depressions in PN and gs were not evident for the well-irrigated plants. With the lower water availability, midday reductions in PN and gs were much more marked and the duration of the depression was longer. Additionally, the PN-irradiance response curves also indicated that water supply affected photosynthesis capacity. The growth and photosynthetic response of P. quinquefolia to water supply indicated that this species could resilient to water availabilities and adapt to Hunshandak conditions very well. and Z. J. Zhang ... [et al.].
The effects of shade on the gas exchange of four Hosta cultivars were determined under differing irradiances (5, 30, 50, and 100 % of full irradiance) within pots. Irradiance saturation ranged between 400-800 μmol m-2 s-1 among the four cultivars, of which H. sieboldiana cv. Elegans and H. plantagenea cv. Aphrodite exerted the lowest saturation and compensation irradiances. The maximal photosynthetic rate (Pmax) was significantly higher in shade than in full irradiance in Elegans and Aphrodite, and was at maximum in seedlings grown in 30 % of full irradiance. The best shade treatment for cvs. Antioch and Golden Edger was 50 % of full irradiance. The diurnal gas exchange patterns in four cultivars were greatly influenced by the irradiance. Single-peak patterns of net photosynthetic rate (PN) and stomatal conductance (gs) were observed under 5 and 30 % full irradiance for all the cultivars while Elegans and Aphrodite suffered from midday depression in 50 % of full irradiance. Under open sky, all four cultivars showed two-peak patters in their diurnal gas exchange, but the midday depression was less in Antioch and Golden Edger than in Elegans and Aphrodite. According to their photosynthetic responses to shade, the shade tolerance of the four cultivars was in the order: Elegans>Aphrodite>Antioch>Golden Edger. and J. Z. Zhang ... [et al.].
Low temperature (LT) is one of the major factors that limit crop production and reduce yield. To better understand the cold-tolerance mechanism in the plantains, a sensitive cultivar Williams (Musa acuminata AAA cv. Williams) and a tolerant cultivar Cachaco (Musa paradisiaca ABB cv. Dajiao) were used. LT resulted in increased malondialdehyde (MDA) content, elevated contents of hydrogen peroxide (H2O2) and superoxide radical (O2.-), and decreased photochemical efficiency (Fv/Fm) and net photosynthetic rate (PN), but cv. Cachaco showed better LT tolerance than cv. Williams. After LT treatment for 120 h, total scavenging capability (DPPH. scavenging capability) in Williams showed a significant decrease but no significant alternations was found in Cachaco. Ascorbate peroxidase (APX) and peroxidase (POD) displayed a significant increase but superoxide dismutase (SOD) showed no significant alternations and catalase (CAT) showed a significant decrease in Cachaco after 120 h of LT treatment. All the four antioxidant enzymes above showed a significant decrease in Williams after 120 h of LT treatment. Our results suggest that higher activities of APX, POD, SOD, and DPPH. scavenging capability to a certain extent can be used to explain the higher cold tolerance in the plantain, which would provide a theoretical guidance for bananas production and screening cold-resistant variety. and Q. Zhang ... [et al.].