Dictyostelium discoideum solutions

The enzyme was prepared from Dictyostelium discoideum. The cells were lysed, and S-100 solutions were prepared from the lysate by differential centrifugation. Samples of this solution were used in the assay. 

The buffered lAF solution is added at a 2- to 6-fold molar excess to a solution of buffer A with Dictyostelium discoideum a-actinin on ice. 

The goal of the research we report here was to determine whether the specific growth rate of predatory amoebae of the cellular slime mould Dictyostelium discoideum feeding on the gut bacteria, Escherichia coli was dependent upon prey density alone or upon the ratio of prey to predator. Two experimental systems were employed, both based on the chemostat type of continuous culture. A chemostat is a continuously stirred tank reactor in which microorganisms grow in a homogeneous environment and are supplied with nutrient solution at the same volumetric rate at... 

CjHiiNsOj, Mr 237.22. The (l J ,2 S) form (L-erythro form) form ale yellow cryst., mp. 250-280 C (decomp.), [a]o-66 (0.1 m HCI), pK, 2.23, pK 2 7.89. In alkaline solution B. shows blue fluorescence. It is widely distributed in microorganisms, insects (e.g. in royaI jelly of queen bees), algae, amphibians, and mammals and is also found in urine. In metabolism tet-rahydro-B. acts as a cofactor for phenylalanine 4-monooxygenase (EC 1.14.16.1). B. is a growth factor for insects. The (l /, 2 /f) form (D-threo form) known as dictyopterin melts at >300 C and has pK , 2.20, pKa2 7.92. It occurs in the slime mold Dictyostelium discoideum. The biosynthesis starts from guanosine triphosphate. 

To date the firefly luciferase gene has been expressed successfully in a large number of cell lines from different organisms (Table 1). Since extracts are likely to contain ATP, the best way to measure luciferase in these samples is to Inject luciferln as the last substrate. Typically the crude extract is mixed with an excess of ATP-Mg buffered solution which is placed in a lumlnometer and the light reaction is initiated by the injection of luclferin. In assay of cell extracts, ATPases, phosphatases or proteases have not been a serious problem in many of the systems analyzed. Mammalian extracts containing luciferase are stable for at least a month at 4 0, whereas extracts from Dictyostelium discoideum are stable for only a few hours unless protease inhibitors are used (26). Diluted purified luciferase is unstable in the absence of other proteins and loses activity rapidly even at 4 C. The situ detection of luciferase has been reported for plant (16), animal (15), yeast (27), bacterial (27) and Dictyostelium (26) cells, and expression has been observed in both transient infections with DNA and in stable cell lines in plant, animal and Dictyostelium cells (15,16,26). 

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