Thesis (Ph. D.)--University of Chicago, Committee on Neurobiology, December 2003. / CD-ROM includes PDF files of the entire dissertation and of the figures alone. Includes bibliographical references. Also available on the Internet.

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Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 4 uppsatser.

Some properties of the adenyl cyclase activity in the maturing testis of Oncorhynchus tshawytscha (chinook salmon) were characterized. The enzymic reaction was linear at 30° and at 15° for at least 60 min. The divalent cation requirement of the salmon testis enzyme was reexamined (33). The optimal concentration of Mg was about 10 mM and of Mn2+ was 5 mM; Mn2+ concentrations above 15 mM caused a marked decrease in enzyme activity. A higher maximal activity was achieved in the presence of Mn2+ than in the presence of Mg2+. Stimulation of the enzyme with the optimal concentration of F-, 12 mM, resulted in a 7-fold increase in the reaction rate over the basal activity. In efforts to solubilize the enzyme, it was found that Lubrol PX and Triton X-100 destroyed enzymic activity but Nonidet P40 and Tween 80 did not. The adenyl cyclase activity in salmon testis homog-enates was stable for at least 6 hours at 0° to 4° but was very unstable at 24°; storage of the homogenate for 24 hours at either 0° to 4° or 24° resulted in a total loss of activity. Differential centrifugation of salmon testis homog-enates which were prepared in isotonic medium revealed tnat all subcellular fractions contained some adenyl cyclase activity. About 55% of the activity sedimented at 600g while only 10% of the activity was recovered in the 105,000g supernatant. The 6300g sediment had a very high specific activity compared with the specific activity of the other fractions. The ATP analogue, adenylyl imidodipho3phate (AMP-PNP), tritium labeled in adenosine, was synthesized from tri-butylammonium imidodiphosphate and adenosine-5’ phosphor-imidazolate. Salmon testis adenyl cyclase catalyzed the conversion of AMP-PNP to cyclic AMP. / Medicine, Faculty of / Biochemistry and Molecular Biology, Department of / Graduate

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2001. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Cornell University, May, 2008. / Vita. Includes bibliographical references (leaves 133-142).

Bordetella pertussis produces a number of virulence determinants believed to contribute to its survival in the host as well as to the pathogenesis of disease. One of these factors, adenylate cyclase toxin (ACT), has been implicated to penetrate human neutrophils and macrophages and abrogate their function by virtue of unregulated production of intracellular cAMP. In order to adequately study the nature of ACT and its role in pathogenesis, it is necessary to isolate the toxin from other virulence factors produced by the organism. Attempts by other investigators to purify ACT and maintain both its invasive and catalytic properties have not been successful. B. pertussis produces a cell associated ACT during mid-log phase of growth in Stainer-Scholte medium. Purification of ACT with both activities from urea extracted whole cells has been achieved by hydroxylapatite and calmodulin-sepharose chromatography. ACT is a single protein of 220 kd molecular weight with an isoelectric point of 7.0. The protein probably contains regions which are strongly hydrophobic. ACT has a specific activity of nearly 17,000 μM cAMP formed/min. An 850 ng sample of ACT induced over 1,400 pmoles cAMP/10⁶ S49 mouse lymphoma cells while 660 ng of ACT inhibited human neutrophil chemiluminescence by 65%.

Thesis (Ph. D.)--Cornell University, August, 2006. / Vita. Includes bibliographical references (leaves 201-220).

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Thesis (Ph. D.)--Cornell University, August, 2006. / Vita. Includes bibliographical references (leaves 157-170.