Browsing by Subject "longevity"
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Item Comparison of F1 cows sired by Brahman, Boran and Tuli bulls for reproductive, maternal, and cow longevity traits(Texas A&M University, 2007-04-25) Maiga, Assalia HassimiBirth weight (BW) (n =1277) and weaning weight (WW) (n = 1090) of calves, pregnancy rate (PR) (n = 1386), calf crop born (CCB) (n = 1386), calf crop weaned (CCW) (n = 1294), cow??????s weight at palpation (CW) (n = 1474) and cow body condition score (BCS) (n = 1473) were evaluated from 1994 to 2006 in 143 F1 cows sired by Brahman (B), Boran (Bo) and Tuli (T) bulls and born to Angus and Hereford cows. Mouth scores (MS) (n = 139) were assigned to the remaining cows in 2004 and 2005. Fixed effects included sire breed of cow, dam breed of cow, and calf??????s birth year/age of cow; random effects included cow and sire of cow. BW and WW were evaluated using the same model and adding gender for both and age for WW. All two-way interactions were tested for significance. Calf??????s birth year/age of dam was significant for all traits (P < 0.05) except WW. BW for calves out of F1 B, Bo and T bulls were 35.08, 34.76 and 34.87 kg, respectively, and were not different. WW differed (P < 0.05) for calves out of F1 B, Bo and T cows (235.87, 221.10 and 208.35 kg, respectively). PR (0.922, 0.955 and 0.936, respectively), CCB (0.881, 0.931, 0.890, respectively), CCW (0.848, 0.898 and 0.869, respectively), did not differ among F1 B, Bo and T cows. CW when cows were 8- or 9-year old were 600.78, 514.63 and 513.14 kg, respectively, for F1 B, Bo and T cows, with those sired by B being heaviest (P < 0.05). BCS for B-, Bo- and T-sired cows were 5.23, 5.48 and 5.18, respectively, with F1 Bo cows having highest scores. Higher MS (P < 0.05) were assigned to Bo and B-sired cows (0.95 and 0.94, respectively) compared to T-sired cows (0.78), when both broken and solid incisors were scored 1, and smooth scored 0. When both smooth and broken were scored 0, and solid were scored 1, higher scores were assigned to B- (0.53) compared to T-sired cows (0.24), the Bo-sired cows being intermediate. Higher reproductive rates were found for Boran-sired cows, but Brahman-sired cows weaned heavier calves.Item Molecular analysis of the role of mitochondria in aging and lengevity(2007-10-10) Kashyap B Choksi; Dr. Steven Weinman; Dr. William R. Widger; Dr. Sankar Mitra; Dr. John Papaconstantinou; Dr. Jeffrey Rabek; Dr. Istvan BoldoghThe Free Radical Theory of Aging states that there is an increase in reactive oxygen species (ROS) production with aging leading to increase in tissue dysfunction. Mitochondria are the major source of ROS, which damages essential macromolecules by oxidative modification and may lead to mitochondrial dysfunction. Accumulation of oxidative damage caused by ROS has been implicated as a major causal factor in the age-associated decline in tissue function and implicated in many age-associated diseases and sarcopenia. Mitochondrial electron transport chain (ETC) complexes I and III are the principle sites of ROS production, and oxidative modifications to their complex subunits inhibit their in vitro activity. Therefore, we hypothesize that mitochondrial complex subunits are primary targets for oxidative damage which may impair their structure/function leading to mitochondrial dysfunction associated with aging.\r\n In addition, numerous studies have identified long-lived mutant mice (i.e., Ames dwarf mice) that suggest that their longevity correlates with oxidative stress resistance. It has not yet been determined whether the mutant mice have inherently lower levels of ROS and whether there are changes in the electron transport chain function compared to wild-type. Therefore, we hypothesize that the dwarf mice have lower levels of ROS-generated lipid peroxidation markers and there are age-related changes in ETC function from tissues of dwarf and wild-type that may play a role in longevity.\r\n In our studies, we have developed a novel methodology for detecting oxidative modification markers using bovine heart mitochondria. In addition, we found that in various mouse tissues ETC proteins are specifically targeted for oxidation and in most cases increased oxidative modifications with aging correlate with decreased enzymatic activities. Thus, we propose that the specificity of the oxidative modification may play a key role in predicting the consequences of ROS-mediate damage. The results from long-lived Ames dwarf mice show that they have lower levels of ROS markers suggesting delayed aging characteristics and except for kidney very little changes in ETC function are noted. Therefore, our studies provide important insight into physiological effects of oxidative modifications on mitochondrial function as well as role of oxidative stress markers in aging and longevity.Item Understanding the genetics of aging: a canine model(Texas A&M University, 2007-04-25) Canterberry, Sarah ChristineAs life expectancy in the United States increases each year, the percentage of the population that is comprised of aged individuals rises also. Researchers expect the largest increase in population to occur in the segment consisting of individuals 85 and older. Thus, investigations of the aging process, with the goals of further extending average life expectancy and improving the quality of life for aged individuals, have become increasingly important to our society. To better understand the genetics of aging, we elected to utilize another model organism, the domestic dog. The benefit to this work is that breeds exhibit extreme, natural variation in life expectancies. Here I report my contributions towards establishing the dog as another model organism for investigations of the aging process. Multiple linear regression analysis was carried out to determine the association between life spans and breed size in the dog, based upon data derived from the American pet population. A negative correlation was observed between both height and longevity and between weight and longevity with weight being the significant predictor of life span. Fifty-four genes implicated in the aging process were mapped to the canine genome. These genes were selected because of their demonstrated contribution to longevity in other organisms or based upon their proximity to a marker, D4S1564, on human chromosome 4. Four genes that are associated with dwarf mice and extended life span were analyzed in nine dog breeds of varying sizes and life expectancies. Fifty-three polymorphisms were discovered in Ghr, Ghrhr, Pit1, and Prop1. Thirteen ancestral SNPs were discovered in which both alleles were found in every breed. In Ghrhr, a transition mutation was found that changes the amino acid sequence as well as the function of the protein and is statistically significant (p=4.8 x 10-6) when large dogs are compared to medium-sized breeds, but not when they are compared to small breeds (p=0.001). This SNP warrants further investigation in additional dogs and breeds.