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Conformational changes in sperm-whale metmyoglobin due to combination with antibodies to apomyoglobin.

ABSTRACT: 1. No ferrihaem was detected in the precipitate formed by metmyoglobin with an antiserum to apomyoglobin and the extinction at 410mmu of metmyoglobin, due to ferrihaem, was decreased by the univalent fragments of apomyoglobin antibodies. It was concluded that the combination of apomyoglobin antibodies with metmyoglobin caused the release of ferrihaem. As the removal of ferrihaem from metmyoglobin is accompanied by a conformational change, it was concluded that the conformation of metmyoglobin was altered by the apomyoglobin antibodies. 2. Antisera to metmyoglobin were divided into two groups; antisera of the first group revealed differences between the immunological reactivities of metmyoglobin and apomyoglobin, whereas no differences were detected with antisera of the second group. 3. Metmyoglobin was only partially re-formed by adding haematin to the precipitate produced by apomyoglobin with an antiserum of the first group, whereas complete re-formation of metmyoglobin was achieved in the presence of antisera of the second group. No metmyoglobin was formed on the addition of haematin to the precipitates produced by either metmyoglobin or apomyoglobin with the anti-apomyoglobin serum. 4. Immune precipitates formed by antisera to metmyoglobin dissociated at pH1.8, whereas those formed by the anti-apomyoglobin serum did not dissociate. 5. These results suggest that apomyoglobin possessed different conformations when combined with metmyoglobin antibodies and apomyoglobin antibodies.

SUBMITTER: Crumpton MJ

PROVIDER: S-EPMC1265114 | biostudies-other | 1966 Jul

REPOSITORIES: biostudies-other

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Project description:Herman Melville's novel Moby Dick was inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical structures in the animal kingdom. It contains two large oil-filled compartments, known as the "spermaceti organ" and "junk," that constitute up to one-quarter of body mass and extend one-third of the total length of the whale. Recognized as playing an important role in echolocation, previous studies have also attributed the complex structural configuration of the spermaceti organ and junk to acoustic sexual selection, acoustic prey debilitation, buoyancy control, and aggressive ramming. Of these additional suggested functions, ramming remains the most controversial, and the potential mechanical roles of the structural components of the spermaceti organ and junk in ramming remain untested. Here we explore the aggressive ramming hypothesis using a novel combination of structural engineering principles and probabilistic simulation to determine if the unique structure of the junk significantly reduces stress in the skull during quasi-static impact. Our analyses indicate that the connective tissue partitions in the junk reduce von Mises stresses across the skull and that the load-redistribution functionality of the former is insensitive to moderate variation in tissue material parameters, the thickness of the partitions, and variations in the location and angle of the applied load. Absence of the connective tissue partitions increases skull stresses, particularly in the rostral aspect of the upper jaw, further hinting of the important role the architecture of the junk may play in ramming events. Our study also found that impact loads on the spermaceti organ generate lower skull stresses than an impact on the junk. Nevertheless, whilst an impact on the spermaceti organ would reduce skull stresses, it would also cause high compressive stresses on the anterior aspect of the organ and the connective tissue case, possibly making these structures more prone to failure. This outcome, coupled with the facts that the spermaceti organ houses sensitive and essential sonar producing structures and the rostral portion of junk, rather than the spermaceti organ, is frequently a site of significant scarring in mature males suggest that whales avoid impact with the spermaceti organ. Although the unique structure of the junk certainly serves multiple functions, our results are consistent with the hypothesis that the structure also evolved to function as a massive battering ram during male-male competition.

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Conformational changes in sperm-whale metmyoglobin due to combination with antibodies to apomyoglobin.

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