Life Sciences Commons^™

Hormone Mediated Transport Of Calcium And Phosphate In Polarized Epithelial Cells, Tremaine M. Sterling

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of 1,25(OH)₂D₃, PTH and 25(OH)D₃ on phosphate or calcium uptake were studied in cultured, adherent chick enterocytes over a period of 10 min after hormone addition. Time course studies of cells treated with 130 pM 1,25(OH)₂D₃ showed an increase in ³²P uptake as early as 3 min. Similar studies with 65 pM bPTH(l1-34) resulted in an increase in ⁴⁵Ca uptake only if the cells had been cultured in serum. (OH)D₃, which is not firmly established as an active metabolite of vitamin D, was shown to increase …

Influence Of Sodium Chloride, Calcium, Moisture, And Ph On The Structure And Functionality Of Nonfat Directly Acidified Mozzarella Cheese, Brian M. Paulson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Experiment A explored the influence of sodium on direct acid, nonfat Mozzarella cheese. Cheeses with differing salt levels were obtained by varying dry salt applications (none, 0.5%, and 1.0% NaCl w/w) and hot brine stretching (0%, 5%, and 10% NaCl wt/v). Salt application and salt content influenced cheese moisture, meltability, expressible serum, micro- and ultra-structure, and color. Moisture was highest when cheese was salted before stretching (P = 0.03). Melt was lowest in cheeses that were unsalted (P = 0.05). Cheeses stretched in salt brine had < 1% of the amount of expressible serum found in unsalted cheese (P < 0.0001). Unsalted cheeses had a more open structure with pockets of serum distributed throughout the protein matrix giving it an opaque, white appearance. Salted cheeses had a more homogeneous protein matrix lacking light scattering surfaces, resulting in a translucent cheese. Neither salt concentration nor method of salting affected the calcium content of the cheeses (P > 0.05).

Experiment B explored the influence of calcium, moisture, and …

Assessment Of Calcium, Milk, And Non-Milk Beverage Intake Of Multiethnic Youth Aged 10 To 18 Years, J. Keith Jensen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Achieving and maintaining maximal peak bone mass is critical to the prevention of osteoporosis. Adequate calcium intake during youth is a major aspect of proper bone mass development. Because of the importance of calcium, a food frequency questionnaire (FFQ) that estimates calcium intake of 10- to 18-year-old Asian, Hispanic, and white youth living in the western United States was developed. This new FFQ was shown to accurately and reliably estimate calcium intake of these youth. Accuracy among Hispanics, however, was low and requires further evaluation. A second study examined intake of calcium, milk, and non-milk beverages of Hispanic and non-Hispanic …

Lifestyle Intervention Program With Calcium Supplementation To Promote Weight Loss And Body Fat Reduction In Overweight Individuals., Candee Meredith Spence

Electronic Theses and Dissertations

The purpose of this study was to determine if there was a significant difference in weight loss, body fat, waist circumference, or diet quality among participants taking calcium or placebo supplements in a lifestyle intervention program. Three participants ages 52-55 completed the 14 week program. Two participants took 1,000 milligrams calcium while one participant took a placebo. Changes in diet were analyzed by Nutribase IV and self perception. Anthropometrics were analyzed by analysis of variance, alpha level 0.05. There was significant decrease in weight and waist circumference for the calcium group and decrease in bioelectrical impedance for the placebo group; …

Analysis Of Microtubule Sliding Patterns In Chlamydomonas Flagellar Axonemes Reveals Dynein Activity On Specific Doublet Microtubules, M. J. Wargo, Mark A. Mcpeek, Elizabeth F. Smith

Dartmouth Scholarship

Generating the complex waveforms characteristic of beating eukaryotic cilia and flagella requires spatial regulation of dynein-driven microtubule sliding. To generate bending, one prediction is that dynein arms alternate between active and inactive forms on specific subsets of doublet microtubules. Using an in vitro microtubule sliding assay combined with a structural approach, we determined that ATP induces sliding between specific subsets of doublet microtubules, apparently capturing one phase of the beat cycle. These studies were also conducted using high Ca2+ conditions. InChlamydomonas, high Ca2+ induces changes in waveform which are predicted to result from regulating dynein

activity on specific microtubules. Our …

Elemental Uptake In Relation To Root Characteristics Of Tall Fescue, Glenn E. Shewmaker, Douglas A. Johnson, Henry F. Mayland, Scott A. Martin, Susie B. Hansen

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

HiMag, an accession of tall fescue (Festuca arundinacea Schreb.), was selected for high magnesium (Mg) concentration in leaves to reduce grass tetany risk to ruminants. However, the mechanism for enhanced Mg uptake in HiMag leaves has not been determined. The objective was to investigate if increased Mg uptake in HiMag could be explained by differences in elemental distribution among plant parts, root characteristics, or organic acid concentrations compared to its parental cultivars, ‘‘Kentucky 31’’ (KY31) and ‘‘Missouri 96’’ (MO96). The study was conducted on a surface-irrigated calcareous Portneuf silt loam (coarse-silty, mixed, mesic, Durinodic Xeric Haplocalcid). Vegetation and soil …

Analysis Of The Mechanism By Which Calcium Negatively Regulates The Tyrosine Phosphorylation Cascade Associated With Sperm Capacitation, Mark Baker, Louise Hethrington, Heath W. Ecroyd, Shaun D. Roman, Robert J. Aitken

Faculty of Science - Papers (Archive)

The capacitation of mammalian spermatozoa involves the activation of a cAMP-mediated signal transduction pathway that drives tyrosine phosphorylation via mechanisms that are unique to this cell type. Controversy surrounds the impact of extracellular calcium on this process, with positive and negative effects being recorded in independent publications. We clearly demonstrate that the presence of calcium in the external medium decreases tyrosine phosphorylation in both human and mouse spermatozoa. Under these conditions, a rise in intracellular pH was recorded, however, this event was not responsible for the observed changes in phosphotyrosine expression. Rather, the impact of calcium on tyrosine phosphorylation in …

The Development Of Signal Transduction Pathways During Epididymal Maturation Is Calcium Dependent, Heath W. Ecroyd, Kelly Asquith, Russell C. Jones, Robert J. Aitken

Faculty of Science - Papers (Archive)

Capacitation has been correlated with the activation of a cAMP-PKA-dependent signaling pathway leading to protein tyrosine phosphorylation. The ability to exhibit this response to cAMP matures during epididymal maturation in concert with the ability of the sperrnatozoa to capacitate. In this study, we have addressed the mechanisms by which spermatozoa gain the potential to activate this signaling pathway during epididymal maturation. In a modified Tyrode's medium containing 1.7 mM calcium, caput spermatozoa had significantly higher [Ca2+](i) than caudal cells and could not tyrosine phosphorylate in response to cAMP. However, in calcium-depleted medium both caput and caudal cells could exhibit a …