Materials and Methods: SF1 was produced by optimized methodology for bioassay-guided fractionation. Fourier transform infrared (FTIR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) were carried out to characterize the SF1. SF1 was screened for cytotoxicity activity toward HeLa, SiHa, and normal cells (NIH) cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. The anticancer mechanism of SF1 was evaluated toward SiHa cells, which showed highest cytotoxicity toward SF1 treatment. The mechanism includes cell cycle progression and protein expression, which was detected using specific antibody-conjugated fluorescent dye, p53-FITC, by flow cytometry.
Results: Major constituents of SF1 were alkaloids with amines as functional group. SF1 showed highest cytotoxic activity against SiHa (half-maximal inhibitory concentration [IC50] < 10 µg/mL) compared to HeLa cells. Cytoselectivity of SF1 was observed with no IC50 detected on normal NIH cells. On flow cytometry analysis, SF1 was able to induce apoptosis on SiHa cells by arresting cell cycle at G1/S and upregulation of p53 protein.
Conclusion: SF1 showed anticancer activity by inducing apoptosis through arrested G1/S cell cycle checkpoint-mediated mitochondrial pathway.
METHODS: To understand the regulation by temperature of leaf phenology in tropical trees, we performed daily observations of leaf production under rainfall-independent conditions using saplings of Shorea leprosula and Neobalanocarpus heimii, both species of Dipterocarpaceae, a dominant tree family of Southeast Asia. We analyzed the time-series data obtained using empirical dynamic modeling (EDM) and conducted growth chamber experiments.
RESULTS: Leaf production by dipterocarps fluctuated in the absence of fluctuation in rainfall, and the peaks of leaf production were more frequent than those of day length, suggesting that leaf production cannot be fully explained by these environmental factors, although they have been proposed as regulators of leaf phenology in dipterocarps. Instead, EDM suggested a causal relationship between temperature and leaf production in dipterocarps. Leaf production by N. heimii saplings in chambers significantly increased when temperature was increased after long-term low-temperature treatment. This increase in leaf production was observed even when only nighttime temperature was elevated, suggesting that the effect of temperature on development is not mediated by photosynthesis.
CONCLUSIONS: Because seasonal variation in temperature in the tropics is small, effects on leaf phenology have been overlooked. However, our results suggest that temperature is a regulator of leaf phenology in dipterocarps. This information will contribute to better understanding of the effects of climate change in the tropics.
METHODS: A cross-sectional electronic survey was conducted at universities in Indonesia, Malaysia, and Pakistan. A 59-item survey was administered between October 2017 and December 2017.
FINDINGS: The survey was completed by 211 students (response rate 77.8%). The mean knowledge score for antibiotic resistance, appropriate antibiotic therapy, and antibiotic stewardship was 5.6 ± 1.5, 4.7 ± 1.8 (maximum scores 10.0) and 3.1 ± 1.4 (maximum score 5.0), respectively. Significant variations were noted among the schools. There was poor awareness about the consequences of antibiotic resistance and cases with no need for an antibiotic. The knowledge of antibiotic resistance was higher among male respondents (6.1 vs. 5.4) and those who had attended antibiotic resistance (5.7 vs. 5.2) and antibiotic therapy (5.8 vs. 4.9) courses (p