. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOSPHATASES OF M \KI\K ALGAE 281 I ^ CL i <0 K 120 100 80 60 40 20 0. COCCOLITHUS (24 UNiTS/m«) A CRICOSPHAERA (36 UNlTS/m!) x THALASSIOSIRA (34UNlTS/m£) • HAEODACTYLUM (40) C14 0----0 PHOSPHORUS O- I 0 20 40 60 80 MINUTES 100 120 140 FIGURE 5. The hydrolysis of C'Mabeled glucose-6-phosphate by P-deficient Coccolitlnts , Cricosphaera cartcri, Tltulussinsit'ii fliti'iatilis and Phaeodactylum triconiutniti. The concentration of the glucose moiety in the medium was determined by measuring C14 (dashed lines
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHOSPHATASES OF M \KI\K ALGAE 281 I ^ CL i <0 K 120 100 80 60 40 20 0. COCCOLITHUS (24 UNiTS/m«) A CRICOSPHAERA (36 UNlTS/m!) x THALASSIOSIRA (34UNlTS/m£) • HAEODACTYLUM (40) C14 0----0 PHOSPHORUS O- I 0 20 40 60 80 MINUTES 100 120 140 FIGURE 5. The hydrolysis of C'Mabeled glucose-6-phosphate by P-deficient Coccolitlnts , Cricosphaera cartcri, Tltulussinsit'ii fliti'iatilis and Phaeodactylum triconiutniti. The concentration of the glucose moiety in the medium was determined by measuring C14 (dashed lines); the concentration of phosphorus remaining in solution (solid lines) \vas determined by the difference between the original concentration and the amount chemically in the cells. Enzyme activity was measured with XPP at the same time in other portions of each culture; results are shown in parentheses (Units/ml, of culture). The following experiment showed that only the phosphate is assimilated and that the organic part of the ester remains in solution. \Yhen C"-laheled G-6-P was mixed with four cultures of I'-deficient algae, radioactive carhon remained in solution while the phosphate was assimilated hy the cells ( Fig. 5 ). (The variability in the C" counts was probably caused by self-absorption and geometry variability.) The simplest explanation is that the phosphate was hydrolyzed extracellularly by phosphatase and taken in. whereas the glucose never entered the cell at all. Thi> is substantiated by the general correspondence between the slopes representing the decline of phosphorus in the medium and the phosphatase activity as measured independently with ^-nitrophenyl phosphate. Location of the enzyme The alkaline phosphatase of the two species studied more carefully, Coccolithus and Phaeodactylum tricornntitin. is firmly attached rather than being in solution in the cell. Repeated attempts on one or the other species, using sonication.
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
