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Biochemistry, Biophysics, and Structural Biology
Loma Linda University Electronic Theses, Dissertations & Projects
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Full-Text Articles in Life Sciences
Molecular Genetics Of Endocrine Induced Regression Of Mouse Leydig Cell Tumors, Milton Rolando Drachenberg
Molecular Genetics Of Endocrine Induced Regression Of Mouse Leydig Cell Tumors, Milton Rolando Drachenberg
Loma Linda University Electronic Theses, Dissertations & Projects
Chronic estrogen treatment results in malignant Leydig cell tumor formation in genetically susceptible strains of mice. The hypothesis that the mechanism of estrogen induced carcinogenesis includes a gene amplification event was tested using this in vivo endocrine carcinogenesis model. High molecular weight DNA isolated from liver, hyperplastic chryptorchid testes, primary Leydig cell tumors and transplanted tumor lines progressing to estrogen nondependence for growth, was studied using Southern blot analysis and the in-gel renaturation technique to identify amplification of characterized and anonymous sequences. No consistent gene amplification event could be demonstrated either in carcinogenesis or tumor progression to an estrogen nondependent …
Aerotaxis In Halobacterium Halobium, Jemima Clara Lindbeck
Aerotaxis In Halobacterium Halobium, Jemima Clara Lindbeck
Loma Linda University Electronic Theses, Dissertations & Projects
Aerotaxis, previously studied in eubacteria was investigated in the archaebacterium Halobacterium halobium. A quantitative temporal assay for aerotaxis of H. halobium was developed using computer assisted motion analysis. Aerotaxis was most pronounced in early log phase cultures. Peak aerotaxis was found to coincide with peak respiration consistent with a model in which respiration is required for aerotaxis. In a spatial assay a mutant strain lacking the proton motive force (pmf)-generating pigments, bacteriorhodopsin (bR) and halorhodopsin (hR), exhibited enhanced aerotaxis bands relative to the bR+hR+ parent. The enhanced aerotaxis in the mutant cells was not due solely to …
Molecular Mechanism Of The Stimulation Of Alkaline Phosphatase Activity In Human Bone Cells By 1,25(Oh)2 D3, Eru Kyeyune-Nyombi
Molecular Mechanism Of The Stimulation Of Alkaline Phosphatase Activity In Human Bone Cells By 1,25(Oh)2 D3, Eru Kyeyune-Nyombi
Loma Linda University Electronic Theses, Dissertations & Projects
To facilitate this study an in vitro human model system was established that exhibited many aspects of normal osteoblasts. The human osteosarcoma cell line (TE85 cells) expressed a skeletal alkaline phosphatase activity (an accepted bone cell differentiation marker) which was stimulated by 1,25(OH)2D3 (a potent differentiating agent), under serum-free conditions in a dose-dependent, time-dependent, and cell density-dependent manner. Cytochemical analysis of the stimulation of ALP activity by 1,25(OH)2D3 showed that 1,25(OH)2D3 increased the number of TE85 cells that expressed detectable ALP activity, suggesting that 1,25(OH)2D3 promoted the process …