Theses and Dissertations at Montana State University (MSU)
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Item Ewe undernutrition alters cotyledon development and function(Montana State University - Bozeman, College of Agriculture, 2023) Welter, Francesca Marie; Chairperson, Graduate Committee: Sarah R. McCoskiUndernutrition is common for animals maintained on rangelands, particularly during periods of drought. Undernutrition during gestation can be detrimental to offspring development. The placenta is a known mediator for maternal-fetal nutrient exchange, and developmental impacts to the placenta during nutritional stress contribute to poor offspring outcomes. The objective of this study was to determine the impacts of maternal nutrient restriction on the development and function of placental cotyledons. Targhee ewes were allocated into two dietary treatment groups for the entirety of gestation. The control group (CON; n = 10) was fed to meet 100% of NRC requirements and the nutrient restricted group (NR; n = 11) was fed to meet 60% of NRC requirements, to mimic the nutritional stress experienced by range ewes during drought. At the time of lambing total placental weight, total cotyledon number, and lamb birth weight was recorded. Cotyledons (n = 3 / placenta) were removed from multiple locations, weighed, and processed for RNA-sequencing. Total placental weight, total cotyledon number, and lamb birth weight were not affected by maternal diet restriction (P > 0.05). Average cotyledon weight was greater in the CON group compared to the NR group (P < 0.05). Gene ontology (GO) and Kyoto encyclopedia of genes and genomes pathways (KEGG) analyses were performed to identify biological pathways involved in placental function and nutrient transfer. Cotyledons from NR singletons vs CON singletons expressed 470 differentially expressed genes (DEGs; P < 0.05; 187 up-regulated, 283 down-regulated). Gene ontology terms represented by DEGs include hormone activity (P = 0.0003) and antigen processing and presentation (P = 0.0004 ). KEGG pathways of interest include pyruvate metabolism, estrogen signaling, extracellular matrix receptor interaction, and antigen processing and presentation. There were also 426 DEGs (P < 0.05; 195 up-regulated, 231 down-regulated) in cotyledons of NR twins vs CON twins. Represented GO categories include heme binding (P = 0.003) and oxidoreductase activity (P = 0.03). These data show that prolonged nutrient restriction alters cotyledon development and gene expression indicating impacts to placental function. These changes in placental function likely mediate poor offspring developmental outcomes observed following gestational under nutrition.Item Maternal injectable mineral during early gestation impacts placental function and calf performance(Montana State University - Bozeman, College of Agriculture, 2022) Ogg, Makayla Anne; Chairperson, Graduate Committee: Sarah R. McCoskiLimited research has evaluated the effects of maternal mineral supplementation during early gestation on placental function and progeny growth. For this study, Angus and SimAngus cows (n = 52) were bred via artificial insemination. At day (d) 60 of gestation, cows were assigned to one of two treatment groups; an injectable group (INJ, n = 26) receiving a single subcutaneous mineral injection and a control group (CON; n = 26). A subset of cows (CON n = 10; INJ n = 6) were selected for liver biopsy at d60 and 209 + or - 1 of gestation. At d139.5 + or - 0.5 and 209 + or - 1 of gestation, uterine artery measurements were collected using Color Doppler ultrasonography. Placentas, liver tissue, and blood samples were collected from the first 11 cows from the subset group that calved (n = 11; CON, n = 5; INJ, n = 6). Analysis revealed a TRT*d interaction at d139.5 + or - 0.5 for circulating Co concentrations which were greater in INJ (P = 0.05) compared to CON cows. Circulating Zn concentrations tended to be decreased at d209 + or - 1 (P = 0.06) in INJ cows compared to the CON cows. Circulating Cu tended to be increased (P-value = 0.09) and Mn was decreased (P = 0.04) in INJ cows throughout the study. A TRT*d interaction was observed at d139.5 + or - 0.5 for non-gravid uterine artery area, diameter, and circumference to be increased in the INJ cows (P = 0.004, 0.006, and 0.006, respectively). Additionally, pulsatility index of the gravid uterine artery tended to be increased (P = 0.09) in the INJ cows. Hepatic Fe concentrations were decreased in the INJ cows (P = 0.01) at d209 + or - 1. Blood and liver samples were collected from calves (CON n = 24; INJ n = 26). INJ calves had greater liver Se concentrations (P = 0.001), lower Fe concentrations (P=0.04), and tended to have increased liver concentrations of Zn (P = 0.09) and Mn (P = 0.08) compared to CON calves. Finally, INJ calves tended to have elevated levels of serum Se (P = 0.09) compared to CON calves. These results suggest that injectable mineral administration during early gestation altered placental function and calf performance.Item Mid-and late-gestation lethality in mice lacking the N terminus of TATA-binding protein(Montana State University - Bozeman, College of Agriculture, 2004) Hobbs, Nicole Kay; Chairperson, Graduate Committee: Edward E. Schmidt.TATA-binding protein (TBP) is a transcription factor comprised of a 180 amino acid core that is shared by all eukaryotes. TBP also has an N-terminal region that, in vertebrates, is highly conserved. We have generated mice bearing a mutant tbp allele, tbp deltaN, that lacks 111 of the 135 amino acids of the vertebrate-specific N terminus. Most homozygous mutants, tbp deltaN/deltaN, die at midgestation from an apparent defect in their placentas. tbp deltaN/deltaN fetuses were rescued at this midgestational crisis if supplied with a wild-type tetraploid placenta. tbp deltaN/deltaN fetuses also survived in immune-normal mothers when fetal/placental beta 2m expression was genetically disrupted. When reared in immunocompromised mothers, tbp deltaN/deltaN fetuses also survived midgestation. These results suggest the N terminus of TBP functions in beta 2M-dependent processes and within the placenta to favor immunotolerance during pregnancy at midgestion. Beyond midgestation, tbp deltaN/deltaN fetuses that survive in immunocompromised mothers were found to be runted at the perinatal period and died shortly after birth. These latter results suggest that the N terminus of TBP also functions in non-immune processes required for normal birth weight and successful pregnancy.