scholarly journals Properties of Vessel Muscle Proteins extracted with Water or Salt Solutions of Low Ionic Strength

Nature ◽  
1961 ◽  
Vol 189 (4760) ◽  
pp. 230-230 ◽  
Author(s):  
L. LASZT
Author(s):  
D. Rittschof ◽  
C.M. Kratt ◽  
A.S. Clare

Gastropod shells are essential to most hermit crabs. Shell availability limits hermit crab populations. Shells provide protection and the degree of shell-fit controls crab growth and fecundity. Crabs locate new gastropod shells from a distance under water by molecules released from gastropod flesh during predation events. Here we test the hypothesis that the salivary glands of the predatory gastropod are the source of enzymes that digest muscle proteins and release peptide attractants. We describe the anatomy of both the acinous salivary glands and the tubular accessory salivary glands of Busycon contrarium which are similar to those of B. carica. The salivary gland ducts empty at the mouth, suggesting a role in the primary digestion of food. We show that gastropod muscle proteins, extracted by salt solutions with the ionic strength of sea water and purified by precipitation in low ionic strength can be digested by gastropod salivary gland enzymes to generate peptides attractive to the hermit crab, Clibanarius vittatus, in field assays.


1996 ◽  
Vol 44 (2) ◽  
pp. 408-415 ◽  
Author(s):  
Ganesan Krishnamurthy ◽  
Hsin-Sui Chang ◽  
Herbert O. Hultin ◽  
Yuming Feng ◽  
Subramanian Srinivasan ◽  
...  

2012 ◽  
Vol 101 (3) ◽  
pp. 965-977 ◽  
Author(s):  
Le Zhang ◽  
Helming Tan ◽  
R. Matthew Fesinmeyer ◽  
Cynthia Li ◽  
David Catrone ◽  
...  

1980 ◽  
Vol 41 (1) ◽  
pp. 135-149
Author(s):  
D. Gingell ◽  
I. Todd

Using both living and glutaraldehyde-fixed red cells, we have examined adhesion to both oil/saline and glass/saline interfaces by interference reflection microscopy. At low ionic strength, 0.4 mM NaCl, fixed cells adherent to the oil/saline interface show first order whitish yellow zones of closest approach which indicate a separation of similar to or approximately 100 nm. Quantitative interferometry in monochromatic light supports this conclusion. As the salt concentration is increased the separation decreases and the final image shows zero-order black which probably indicates molecular contact with the interface. Similar but less reproducible results were obtained with fixed and unfixed cells on glass. Thes observations show that physical interactions alone can be responsible for adhesion in dilute and concentrated salt solutions. It is not, however, believed that the results necessarily imply the existence of adhesion with a gap in physiological concentrations of salt.


Author(s):  
J.S. Wall ◽  
V. Maridiyan ◽  
S. Tumminia ◽  
J. Hairifeld ◽  
M. Boublik

The high contrast in the dark-field mode of dedicated STEM, specimen deposition by the wet film technique and low radiation dose (1 e/Å2) at -160°C make it possible to obtain high resolution images of unstained freeze-dried macromolecules with minimal structural distortion. Since the image intensity is directly related to the local projected mass of the specimen it became feasible to determine the molecular mass and mass distribution within individual macromolecules and from these data to calculate the linear density (M/L) and the radii of gyration.2 This parameter (RQ), reflecting the three-dimensional structure of the macromolecular particles in solution, has been applied to monitor the conformational transitions in E. coli 16S and 23S ribosomal RNAs in solutions of various ionic strength.In spite of the differences in mass (550 kD and 1050 kD, respectively), both 16S and 23S RNA appear equally sensitive to changes in buffer conditions. In deionized water or conditions of extremely low ionic strength both appear as filamentous structures (Fig. la and 2a, respectively) possessing a major backbone with protruding branches which are more frequent and more complex in 23S RNA (Fig. 2a).


1960 ◽  
Vol 4 (01) ◽  
pp. 031-044
Author(s):  
George Y. Shinowara ◽  
E. Mary Ruth

SummaryFour primary fractions comprising at least 97 per cent of the plasma proteins have been critically appraised for evidence of denaturation arising from a low temperature—low ionic strength fractionation system. The results in addition to those referable to the recovery of mass and biological activity include the following: The high solubilities of these fractions at pH 7.3 and low ionic strengths; the compatibility of the electrophoretic and ultracentrifugal data of the individual fractions with those of the original plasma; and the recovery of hemoglobin, not hematin, in fraction III obtained from specimens contaminated with this pigment. However, the most significant evidence for minimum alterations of native proteins was that the S20, w and the electrophoretic mobility data on the physically recombined fractions were identical to those found on whole plasma.The fractionation procedure examined here quantitatively isolates fibrinogen, prothrombin and antithrombin in primary fractions. Results have been obtained demonstrating its significance in other biological systems. These include the following: The finding of 5 S20, w classes in the 4 primary fractions; the occurrence of more than 90 per cent of the plasma gamma globulins in fraction III; the 98 per cent pure albumin in fraction IV; and, finally, the high concentration of beta lipoproteins in fraction II.


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