Xanthigen promoted weight loss, reduced body and liver fat content, and improved liver function tests in obese non-diabetic women. Xanthigen and Fucoxanthin also increased REE. This product may be considered a promising food supplement in the management of obesity.

In green unicellular algae, several polypep-

An intracellular carbonic anhydrase (CA; EC 4.2.1 .I) was purified to homogeneity from a mutant strain of Chlamydomonas reinhardtii (CW 92) lacking a cell wall. lntact cells were washed to remove periplasmic CA and were lysed and fractionated into soluble and membrane fractions by sedimentation. All of the CA activity sedimented with the membrane fraction and was dissociated by treatment with a buffer containing 200 mM KCI. Solubilized proteins were fractionated by ammonium sulfate precipitation, anionic exchange chromatography, and hydrophobic interaction chromatography. l h e resulting fraction had a specific activity of 1260 WilburAnderson units/mg protein and was inhibited by acetazolamide (50% inhibition concentration, 12 nM). Final purification was accomplished by the specific absorption of the enzyme to a Centricon-10 microconcentrator filter. A single, 29.5-kD polypeptide was eluted from the filter with sodium dodecyl sulfate-polyacrylamide gel electrophoresis sample buffer, and a 1.5 M ammonium sulfate eluate contained CA activity. I n comparison with human CA isoenzyme II, the N-terminal and internal amino acid sequences from the 29.5-kD polypeptide were 40% identical with the N-terminal region and 67% identical with an internal conserved region. Based on this evidence, we postulate that the 29.5-kD polypeptide i s an internal CA in C. reinhardtii and that the enzyme is closely related to the a-type CAs observed i n animal species.

The growth characteristics, biochemical composition and ultrastructure of a novel starchless mutant of Chlorella pyrenoidosa, designated as STL-PI, are compared to the same characteristics of its parental strain, C. pyrenoidosa 82T. The STL-PI mutant had a 22 ± 5% higher growth rate, and 24.5 ± 4.2% more protein than the parental strain, 82T. Furthermore, the STL-PI mutant accumulated 20.4% more polyunsaturated fatty acids and 18% less saturated fatty acids than the parental 82T. When the parental 82T was cultured in a nitrogen-free media, their starch content increased from 6.8 ± 2.8% to 22.5 ± 3.1%. In contrast, the STL-PI mutant produced no starch, regardless of the growth conditions. Instead, the mutant cells responded to nitrogen limitation by further increasing their lipid content from 25.2 ± 1.2% to 38.0 ± 2.3% per dry weight. Transmission electron micrography revealed that nitrogen limitation typically stimulates the formation of starch granules in the chloroplast of 82T cells. Yet no starch granules were observed in the STL-PI cells. Instead, only the formation of large lipid globules was observed in the mutant cells. These results demonstrate that the starchless mutant STL-P1 possesses novel physiological and phytochemical properties distinct from the 82T cells: their cells were deficient in starch synthesis and showed higher growth rates and productivity than 82T cells.

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The role of extracellular carbonic anhydrase (CAex) for dissolved inorganic carbon (DIC) accumulation in the green alga Chlamydomonas reinhardtii was investigated. It was found that when algal cells were bubbled with ambient air, cell‐wall‐less mutant cells exhibited the same high photosynthetic affinity for CO2 as wild‐type cells despite a 10 times lower activity of CAex. It was also found that the affinity for CO2 was further increased when the total DIC concentration of the algal medium was reduced from that in equilibrium with ambient air to even lower levels. This increased affinity was not correlated with any further increase in the CAex activity. Dextran‐bound sulfonamide (DBS. 100 μM bound ligand) completely inhibited the activity of CAex in intact, low‐DIC grown, wild‐type cells, while photosynthesis at <2 μM CO2(aq) proceeded at a far greater rate than could be maintained by CO2 supplied from the spontaneous dehydration of HCO−3. DBS‐inhibition of CAex, during the induction of the DIC‐accumulating mechanism in previously high‐DIC grown cells, only caused a 50% inhibition of photosynthesis at 10 μM CO2(aq) after 1 h of low‐DIC acclimation. It was also shown that 50 μM acetazolamide (AZ) inhibited photosynthesis at low DIC concentrations to a relatively higher degree than DBS, suggesting that AZ inhibited intracellular CA as well. Taken together, these results suggest that low‐DIC grown cells of C. reinhardtii have the ability to transport HCO−3 across the plasma membrane in addition to the CAex‐mediated, facilitated diffusion and/or transport of CO2. It is also suggested that the relative importance of these two fluxes (CO2 or HCO−3) is dependent on the growth and experimental conditions. Facilitated CO2 uptake seems to be most prevalent, supported by HCO−3‐transport under more or less extreme situations, such as a reduction of CO2 to extremely low concentrations, leakage of CAex to the medium as in cultures of cell‐wall‐less mutant cells or when the activity of CAex has been artificially inhibited.

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Lipid content, fatty acids and sterol composition of Cystoseira abies-marina and total fatty acids of C. humilis from Gran Canaria were studied. A high content of polyunsaturated fatty acids 16 : 3 and 16: 4 was found. Their content in rnonogalactosyldiacylglycerols is over 90%. Triacylglycerols and phospholípids contain rnainly arachidonic and eicosapentaenoic acids. Reasons for the differences in the composition of fatty acids and sterols of various species of Cystoseira are discussed. Sorne technological approaches are recommended.