The objective of this study was to examine the effects of two thermal processes, drum-drying and thermoplastic extrusion, on protein quality and digestibility of whole wheat. Coker 916 whole wheat flour was made into a simulated whole wheat spaghetti by extrusion cooking (single screw, 50 psi, 93°C) and a flaked product by drum-drying (152°C). Protein Efficiency Ratios (PER) of the original whole wheat kernels and the two processed wheat products were determined. The apparent digestibility of the four diets was determined from Kjeldahl nitrogen analysis of feces. Amino acid composition, available lysine analysis, colorimetry (Hunter L, a, b color values), and Differential Scanning Calorimetry were also conducted to investigate the effects of thermal processing on protein quality. Both thermal processes significantly increased protein digestibility while PER’s of the drum dried flakes (1.66) and unprocessed whole wheat (1.59) were significantly greater than the extruded product (1.42) Thermal processing also resulted in substantial reductions in lysine (>10%) and several other essential amino acids. Hunter L, a, b values indicated that the drum-dried flakes were lightest in color, followed by the unprocessed whole wheat and the extruded product. The observed decrease in lysine and PER of the extruded product may be due in part to Maillard Browning, as indicated by Hunter color values. It appears that total lysine or Hunter L color values may be reasonable predictors of protein quality of processed whole wheat. DSC results suggest that starch was fully gelatinized during drum-drying of the whole wheat but on partially gelatinized during extrusion cooking. / Master of Science

The objective of this investigation was to determine the effects of restricted movement and forced exercise on protein metabolism and body composition of adult rats. Half of the animals were restricted in movement and half of each group were forced to exercise by swimming for ten days. The study entailed a six day adjustment period, a four day balance study, and a ten day exercise period followed by another four day balance study. Weight change, food consumption, nitrogen retention, liver composition, and body composition were analyzed to test the effects of the treatments. Restricted animals retained less nitrogen than the controls, but negative nitrogen retentions expected when animals were losing weight did not occur. Changes in body fat correlated positively with body weight change. After about fifteen days of restriction, the animals seemed to adapt to the inactivity. This was indicated by an increase in food consumption and a dramatic change from weight loss to weight gain. Considerable variation existed in the ability of individual animals to adapt. Some animals did not adapt at all, and died early in the study. Other animals adapted readily and gained weight in excess of their initial weight loss. Ten minutes of swimming daily for ten days did not cause observable effects on the restriction. The adaptation seems to indicate that the expected weight loss and decreased nitrogen retentions will not be a problem. / M.S.

Degradability in the rumen of several protein sources was determined by suspending from 12 to 13 g of feedstuff in dacron bags into the rumen for 0, 2, 6, 12, 24, 36, 48, and 72 h. Rumen cannulated lactating Holstein cows consuming a diet of corn silage, alfalfa, soybean, and high moisture corn were used. Degradability of protein varied from 18.6% for corn gluten meal to 72.3% for soybean meal. Gel electrophoresis was used to monitor rates of degradation in the rumen of fractions of corn gluten (CGM), CORN, cottonseed (CSM), peanut (PM), and soybean meal (SBM) protein fractions. Fractional degradation rates in the rumen were determined from densitometric analysis of stained polypeptides bands on SDS-PAGE gels. Acidic subunits of soybean glycinin were degraded at a faster rate than basic subunits (.144 vs .104 h⁻¹). Rates of degradation of zein in corn and corn gluten meal were .026 and .015 h⁻¹, respectively. Protein degradability estimated by using B subfractional components did not differ from degradability measured using total B fractions. Lag phase associated with dacron bags suspension technique did not change effective degradability. Protein solubility in SDS-PAGE sample buffer was highly correlated (R²=.958) with in situ protein degradability of CORN, CSM, DBG, FM, PM, and SBM. Different rates of degradation of each fraction may directly influence protein and amino acid contribution to the animal. / Master of Science

A fifteen day balance study was conducted to test the value of two diets providing 24 and 16 gm. of plant-protein daily and to approach the approximate minimum protein requirement using plant proteins for a 23-month old Chinese girl weighing 12 kg. The diets were supplemented to bring nutrients to the NRC recommended allowances except for protein and calories. Essential amino acids were planned to approximate the FAO provisional pattern. Nitrogen determinations were made on food, urine and feces. Food composites for each diet were analyzed for nine of the essential amino acids using a Beckman/Spince Model 120 Amino Acid Analyzer. Tryptophan was determined by microbiological assay. Nitrogen in the diets averaged 3.96 and 2.69 gm. respectively for the two protein levels of 24 and 16 gm. daily with retention of 0.33 gm. daily for all periods, or 0.48 gm. and 0.44 gm. for the test periods. The essential amino acids as analyzed represent 59 per cent and 34 per eent of the total protein in the moderate and low protein diets. The analyzed amino acid patterns were as follows: tryptophan 1.0 and 1.0; threonine 2.8 and 2.2; isoleucine 5.8 and 3.5; leucine 9.4 and 5.5; lysine 3.1 and 3.7; methionine 1.2 and 0.8; phenylalanine 6.1 and 3.6; valine 6.7 and 3.9; arginine 4.4 and 4.5; and histidine 1.3 and 2.0. A positive nitrogen retention of better than 0.4 gm. daily (0.033 gm./kg.) was obtained with daily nitrogen intake of 0.33 and 0.22 gm. per kg. of body weight for this 23-month old girl with approximately 90 and 84 calories per kg. per day. / Master of Science

One of the major unresolved questions in cancer biology is why the majority of tumour cells express mutant p53 proteins. p53 is considered the prototype tumour suppressor protein, whose inactivation is the most frequent single genetic event in human cancer (Bourdon et al., 2005). Genetically-engineered p53-null knockout mice acquire multiple tumours very early on in life and human Li-Fraumeni families who carry germline mutations in p53 are highly cancer-prone (reviewed in Vousden and Lane, 2007). p53 mutant proteins have been found to acquire novel functions that promote cancer cell proliferation and survival, yet exactly why mutant p53s acquire oncogenic activity is still poorly understood. Mutant p53 has also been found to complex with wildtype p53, thus acting in a dominant negative way. However, this inhibition is incomplete since many cancers with mutant p53 alleles also have a loss of the second wild-type p53 allele and thus only express the mutant p53 (Baker et al., 1989). An N-terminal truncated p53 isoform, p47, arising from alternative splicing of the p53 gene (Ghosh et al., 2004) or by alternative initiation sites for translation (Yin et al. , 2002), has been described. Alternative splicing was found to be universal in all human multi-exon genes (Wang et al., 2008) and therefore determining the role of the p47 isoform with respect to the p53 gene is essential. Evidence in this study suggests that mutant p53 (p53RI75H) has a similar structure and function as p47, including the ability to complex with and impair both p53 and p73. Therefore, in addition to expressing a tumour suppressor protein, the p53 gene can also express an onco-protein (p47). This study therefore argues that tumours select for mutant p53 because it has gained the ability to function like p47, a wild-type p53 isoform.

The HPV E6-p53 interaction is well-understood, but not for all high-risk HPV types. In addition, HPV E6 p53-independent functions are gaining recognition for their importance in cellular transformation but require clarification. Thus, the aim of this study was two-fold: (1) to gain insight into the p53-E6 interaction for high-risk HPV-33 and, (2) to explore how high-risk HPV E6 proteins targets cellular MAGI-3 for degradation. / In vivo and in vitro results indicated that E6 from HPV types 18 and 33 interacted similarly with p53 although, variants of the HPV-33 E6 prototype demonstrated interesting disparities. Of note was HPV-33 E6 variant 2, which degraded p53 more efficiently than prototype HPV-33 E6 and HPV-18 E6. The E6 protein from HPV types 18 and 33 also potently degraded MAGI-3 via a different pathway than that used for p53. Specifically, proteasome inhibition did not interfere with MAGI-3 degradation and MAGI-3 was not ubiquitinated in the presence of the E6 protein. / Therefore, the results described herein enhance our understanding of high-risk HPV type 33 E6 and the E6-MAGI-3 interaction.

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No description available.

Mechanisms of post-transcriptional control are critical to deploy RNAs and proteins asymmetrically to a discrete region of cytoplasm at the posterior of the Drosophila oocyte and embryo, called the pole plasm and thus allow differentiation of the germline. Research presented in this thesis investigates the post-transcriptional control of Drosophila pole plasm component germ cell-less (gcl ). Maternal gcl activity is required for germ cell specification and gcl RNA and protein accumulate asymmetrically in the pole plasm. gcl RNA, but not Gcl protein, is also detected in somatic regions of the embryo, and ectopic expression of Gcl in the soma causes repression of somatic patterning genes suggesting that gcl RNA is subject to translational control. I find that Gcl is expressed during oogenesis, where its expression is regulated by translational repressor Bruno (Bru). Increased levels of Gcl are observed in the oocyte when Bru is reduced (i.e., in an arrest heterozygote) and Bru overexpression reduces the amount of Gcl. Consistent with this, reduction of the maternal dosage of Bru leads to ectopic Gcl expression in the embryo, which, in turn, causes repression of anterior huckebein RNA expression. Bruno binds directly to the gcl3'UTR in vitro, but surprisingly, this binding is largely independent of a Bruno Response Element (BRE) in the gcl 3'UTR and depends upon a novel site. Furthermore, the gcl BRE-like region is not required to repress Gcl expression during oogenesis or embryogenesis. I concluded that Bru regulates gcl translation in a BRE-independent manner. In addition, I established the role of the gcl 3'UTR in gcl RNA localization and translation using transgenes that replace the endogenous 3'UTR with the alpha-tubulin 3'UTR or place it in tandem to the bicoid 3'UTR. I find that accumulation of gcl RNA in the embryonic pole plasm requires the gcl 3'UTR. Moreover, Gel is restricted to the pole plasm by translational repression mediated by the gcl 3'UTR and a limiting pool of trans-acting translational repressors. The phenotypic consequences of loss of this translational control are relatively mild, suggesting that gcl translation does not require stringent repression in the soma.

No description available.