Influence of stress factors on growth and pigment production in three Dunaliella species cultivated outdoors in flat-plate photobioreactors

Abstract

Growth and production of carotenoid in three Dunaliella species (Dunaliella salina (Dunal) Teodoresco, Dunaliella bardawil Ben-Amotz & Avron and Dunaliella sp.) were investigated using flat-plate photobioreactors in outdoor conditions with two optical paths (3?cm and 5?cm). The experiment was conducted in duplicate and lasted four weeks during which light intensity, temperature, pH and optical density were checked daily. The pigment production (total carotenoid and chlorophyll a) was monitored every two days. To induce an additional stress besides temperature and light intensity, two different salt concentrations were used, i.e. 6% and 8% NaCl. The highest growth in all treatment groups was noticed for Dunaliella sp. followed by D. bardawil and D. salina. D. salina produced a higher content of carotenoid concentrations corresponding to 5?cm/8% and 5?cm/6% groups; 779.102?±?0.434?μg.mL^?1 and 694.326?±?0.098?μg.mL^?1 were registered at the end of the experiment. The same species had also greater content of β-carotene.     

Sialic acid levels in various types of cancer.

Serum or plasma total sialic acid (TSA) and lipid bound sialic acid (LSA) are useful markers for human cancer. In this study, sialic acid levels have been demonstrated in various types of human cancer including brain, thyroid and Hodgkin's. TSA was found to be significantly elevated in various human brain tumors, especially in the microsomal fraction. Also serum and tissue LSA levels indicated significant increases when compared to the normals in various brain and thyroid tumors. TSA levels were significantly higher in the plasma and leucocyte in patients with Hodgkin's. The results show that sialic acid can be advisable as a beneficial marker for detecting malignancies. But it can not be used as a criteria for identifying tumor types.     

Overcoming drug resistance in hormone- and drug-refractory prostate cancer cell line, PC-3 by docetaxel and gossypol combination

Drug resistance is a significant challenge of daily oncology practice. Docetaxel and gossypol both have antitumoral activity in hormone-refractory prostate cancer (HRPC). Our results revealed that docetaxel and gossypol were synergistically cytotoxic and apoptotic in PC-3 cells in a dose- and time-dependent manner. We further investigated the expression profiles of genes involved in drug resistance and metabolism with a Human Cancer Drug Resistance and Metabolism PCR Array^® (SuperArray). Six of the 84 genes that are known to regulate drug resistance, metabolism, cell cycle, DNA repair and oncogenesis were downregulated ≥3-fold change by the combination treatment. These results may be important in devising mechanism-based and targeted therapeutic strategies for prostate cancer, especially in devising combination therapy for drug resistant prostate cancers.     

Urine analysis using FTIR spectroscopy: A study on healthy adults and children

Urine spectra from 108 healthy volunteers are studied by attenuated total refraction-Fourier transform infrared (ATR-FTIR) spectroscopy. The spectral features are correlated with observable urine components. The variation of spectra within a healthy population is quantified and a library of reference spectra is constructed. Using the band assignments, these spectra are compared with both age-wise and gender-wise. Children show the least intensity variations compared to both adult groups. Young adults show the highest variation, particularly in the 1650 to 1400 cm⁻¹ and 1200 to 900 cm⁻¹ regions. These results indicate the importance of the size of the control group in comparative studies utilizing FTIR. Age-wise comparisons reveal that phosphate and sulfate excretion decreases with age, and that the variance of phosphate among individuals is higher with adults. As for gender-wise comparisons, females show a slightly higher citrate content at 1390 cm⁻¹ regardless of the age and they show a higher variance in the 1200 to 1000 cm⁻¹ region when compared to men.