. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 200 300 400 [Antibiotic] (\iM) 500 Figure I. Incorporation of ['H]leucine as a function of the concen- tration of antibiotic. After incubating 8-l()-day-old larvae (ca. lar- vae/10 ml rifampicin-containing seawater) for 2 h in the presence or absence of blocker at the concentrations indicated, [3H]leucine was added to /iCi/ml, and the pulse allowed to proceed for 2 h. Mean control values (representing incorporation in the absence of antibiotic) are dis- placed on the abscissa for clarity. (A) Incorporation in t
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 100 200 300 400 [Antibiotic] (\iM) 500 Figure I. Incorporation of ['H]leucine as a function of the concen- tration of antibiotic. After incubating 8-l()-day-old larvae (ca. lar- vae/10 ml rifampicin-containing seawater) for 2 h in the presence or absence of blocker at the concentrations indicated, [3H]leucine was added to /iCi/ml, and the pulse allowed to proceed for 2 h. Mean control values (representing incorporation in the absence of antibiotic) are dis- placed on the abscissa for clarity. (A) Incorporation in the presence of emetine (diamonds) or anisomycin (rectangles). (B) Incorporation in the presence of cycloheximide (diamonds), puromycin (rectangles), tetra- cycline (triangles), or fusidic acid (circles). Details as described in Materials and Methods. assays (ca. 2000 larvae/10 ml seawater), and observed for mortality and other responses to the protein synthesis in- hibitors. Results Inhibition of protein synthesis Larvae of H. rufescens take up exogenous amino acids from seawater, as demonstrated by these and other in- vestigations (Jaeckle and Manahan, 1989), although these larvae are lecithotrophic. Several commonly used inhib- itors of protein synthesis, including cycloheximide, fusidic acid, puromycin, and tetracycline, had little or no inhib- itory effect on the overall incorporation of [3H]leucine into TCA-insoluble material at concentrations that were not toxic to the larvae (Fig. 1). In marked contrast, both emetine and anisomycin proved strongly inhibitory in a concentration-dependent manner. Emetine (9 n.\f) efficiently blocked the incorporation of [3H]leucine into Haliotis larvae under conditions in which 100 nM chloramphenicol (an inhibitor of protein synthesis only in prokaryotes) had no significant effect (Fig. 2A). Identical results were obtained for a range of chloramphenicol concentrations (50-600 n.\f), both in the presence or absence of pM rifampicin (an
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
