. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ALANINE TRANSPORT IN ZOOXANTHELLAE 413 1. 200 £ O 0> 51 £L Q LU 100 • L -Alanine • .>-Alanine D AIB. TIME (Mrs) FIGURE 2. Uptake of L-(l-'4C)alanine, /3-alanine, and a-aminoisobutyric acid (AIB) by isolated zooxanthellae. with the results reported for this amino acid in a wide variety of cells (Guidotti et al, 1978; Christensen, 1979, 1982). Uptake systems for alanine in zooxanthellae Sodium-dependent alanine uptake occurs in a variety of cell types via two systems designated A and ASC by Christensen (1979) and co-work
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ALANINE TRANSPORT IN ZOOXANTHELLAE 413 1. 200 £ O 0> 51 £L Q LU 100 • L -Alanine • .>-Alanine D AIB. TIME (Mrs) FIGURE 2. Uptake of L-(l-'4C)alanine, /3-alanine, and a-aminoisobutyric acid (AIB) by isolated zooxanthellae. with the results reported for this amino acid in a wide variety of cells (Guidotti et al, 1978; Christensen, 1979, 1982). Uptake systems for alanine in zooxanthellae Sodium-dependent alanine uptake occurs in a variety of cell types via two systems designated A and ASC by Christensen (1979) and co-workers (Kilberg et al., 1980, 1981; Handlogten et al., 1981). System A functions primarily in the uptake of neutral amino acids with short, polar, or linear side-chains. A sub-set of System A, the ASC System, has the greatest affinity for three such amino acids: alanine, serine, and cysteine. Transport of an amino acid such as alanine by each of these systems can be distinguished by competition experiments using the methylated analog a-meth- ylaminoisobutyric acid (MeAIB). This analog competes for uptake sites of System A but not of System ASC. In contrast to these systems, System L is sodium-independent and transports neutral aromatic amino acids or those that have branching side-chains. Since these systems are characteristic of a variety of cell types, similar mechanisms in zooxanthellae may provide a basis for the interpretation of alanine uptake in the presence of the competing amino acids or analogs (Table I). The lack of a large reduction of alanine uptake in the presence of MeAIB (10% of control) would argue that the ASC System serves as the major uptake system for alanine in zooxanthellae. The predominance of the ASC System is also consistent with the reduction of alanine. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resem
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
