. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 370 SILVERMAN ET AL. siphons were clearly visible. Drops of 2% OsO4 (1-2 mil were slowly added near the edge of the container; the specimen was left intact for 20 min. The posterior adductor muscle was then cut and the animal exposed to fixative for another 40 min. In a few cases, the adductor muscle was carefully cut before OsO4, was added, with total exposure to osmium in the bath being 30 min. The mussels were then rinsed in seawater and fixed for an hour in 2% glutaralde- hyde in seawater. After fixation, the gill was re
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 370 SILVERMAN ET AL. siphons were clearly visible. Drops of 2% OsO4 (1-2 mil were slowly added near the edge of the container; the specimen was left intact for 20 min. The posterior adductor muscle was then cut and the animal exposed to fixative for another 40 min. In a few cases, the adductor muscle was carefully cut before OsO4, was added, with total exposure to osmium in the bath being 30 min. The mussels were then rinsed in seawater and fixed for an hour in 2% glutaralde- hyde in seawater. After fixation, the gill was removed, dehydrated in a graded ethanol series, critical-point dried, and sputter-coated with gold-palladium. Specimens were mounted on stubs and visualized with a Cambridge Scan- ning Electron Microscope. Some gills were removed and photographed before and after fixation, and again after critical-point drying to monitor tissue shrinkage. Bacterial clearance Clearance of "S-labeled Excherichia coli from the bath- ing medium was quantified with an adaptation of the method of Riisgard (1988) as described previously (Silver- man et al, 1995, 1997). Mussels (< 30 mm shell length) were placed in individual test tubes containing 20 ml aer- ated artificial seawater (5°C) with or without 10~3 M sero- tonin for 15 min. Radiolabeled bacteria were added to each tube after the mussels opened their siphons, and after 1 min equilibration, four samples (100 /Ltl) were collected at 10- min intervals. The reduction of bathing medium radioactiv- ity followed first order kinetics, and the clearance was expressed as ml g~' dry tissue min" '. Data are expressed as the mean ± one standard error with the number of animals in parentheses. Results Cimil structure Progressive fixation stopped the cirri and cilia in various stages of their beat cycle. The cirri position varied from being arched over the frontal surface of a gill filament to extending into the interfilument space (Fig. 1). Ad
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
