Substances with valuable antitumor properties have been identified in many marine algae, including an edible polysaccharide from the marine alga Gracilariopsis lemaneiformis (PGL). We previously reported transcriptome profiling data showing that PGL induced transcriptional alterations generate anti-lung cancer activity. To identify how PGL is detrimental to tumors, we purified PGL to characterize its chemical composition, molecular weight, and sugar and protein content and investigated its antitumor activity. We demonstrated that PGL exerted its antitumor activities by modulating cell viability, morphology, apoptosis, and the apoptosis-related Fas/FasL signaling pathway in the human lung cancer cell line A549, the gastric cancer cell line MKN28, and the mouse melanoma cell line B16. Our data provide the first evidence that PGL inhibits cell proliferation by inducing apoptosis, which is largely mediated by Fas/FasL in cancer cells, suggesting that PGL might be a novel therapeutic agent against cancer.

The biodegradation of terephthalic acid (TA) by the Pseudomonas sp. was researched in this paper. The optimal nitrogen source was urea with its concentration of 1400 mg/l. The optimal conditions for TA degradation were optimized by orthogonal test. The test result showed the pH 7.0, temperature of 30°C and shaking speed of 140 rpm were the best condition for degradation. In that condition, terephthalic acid was almost degraded completely after 48 h cultivation ofPseudomonas sp. by inoculating 4% seed culture. Kinetics of degradation was performed at different initial TA concentrations. The degradation could be described with a first-order kinetics model. The half-life of degradation was about 12 h when the concentration of terephthalic acid was between 600 and 1000 mg/l. Key words: Biodegradation, terephthalic acid, Pseudomonas sp