. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PROMOTION AND INHIBITION BY MATRIX 195 : Control Pre-ecdysis/A Pre-ecdysis/F Postecdysis/A PostecoVsis/FA. 37 46 56 65 Time (minutes) Figure 1. Promotion of CaCOi crystallization by coupons cut from new cuticle of blue crabs at pre-ecdysis and postecdysis (Stage A-B), following decalcincation in either 2'S acetic acid (A), 4"i formaldehyde (F) to crosslink soluble proteins, or 4% formaldehyde in 2% acetic acid (FA). Crystallization was measured as a downward pH drift, reflecting the removal of CO,: from solution
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PROMOTION AND INHIBITION BY MATRIX 195 : Control Pre-ecdysis/A Pre-ecdysis/F Postecdysis/A PostecoVsis/FA. 37 46 56 65 Time (minutes) Figure 1. Promotion of CaCOi crystallization by coupons cut from new cuticle of blue crabs at pre-ecdysis and postecdysis (Stage A-B), following decalcincation in either 2'S acetic acid (A), 4"i formaldehyde (F) to crosslink soluble proteins, or 4% formaldehyde in 2% acetic acid (FA). Crystallization was measured as a downward pH drift, reflecting the removal of CO,: from solutions ol supersaturated artificial seawater. Promotion of crystallization was indicated by a reduction of the induction period prior to the pH decrease in control solutions. Error bars represent typical standard deviations (n = 3). lutions with and without formaldehyde. However, there was no significant difference in the ability of coupons to promote crystallization. The ability of coupons to promote crystallization was reduced with prolonged storage (data not shown). Acid-washed pre-ecdysial cuticle did not pro- mote crystallization, presumably because there were few immobilized matrix proteins present. In contrast, cross- linking of soluble protein on pre-ecdysial cuticle promoted crystallization equal to that of formaldehyde-treated or acid-washed postecdysial (stage A-B) cuticle of compa- rable dry weight (Fig. 1). Coupons of chitin, which should not have protein, did not promote crystallization (Table II), indicating that the protein components may function as nucleating sites. That the downward pH shifts during the crystallization assays did indeed indicate growth of CaCO? crystals was verified in three ways: by measurements of calcium on the coupons, by comparison of these measurements to calculations of the amount of carbonate removed from solution, and by the presence of birefringence on the cou- pons that was acid labile. For example, the coupon that was treated in 4% for
Size: 2044px × 1223px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
