Apoptosis is executed by caspase-mediated cleavage of various proteins. Elucidating the consequence of substrate cleavage provides us with insight into cell death and other biological processes. In this study, we applied the diagonal gel approach, a proteomic strategy, to identify substrates of the inflammatory caspase, caspase-1 and the cell death executioner caspase, caspase-3. Our results showed significant overlap between the substrates cleaved by both caspase-1 and -3. Such substrates are implicated in common cellular functions, including maintenance of the cytoskeleton, folding of proteins, translation, glycolysis, bioenergetics, signaling and trafficking. An important finding is that many glycolysis enzymes were targeted specifically by caspase-1. Processing of these glycolysis enzymes by caspase-1 was confirmed by cleaving in vitro transcribed and translated substrates with recombinant caspase-1. We have focused our further analysis on certain glycolysis enzymes. We have characterized the caspase-1 cleavage site in GAPDH. Point mutation of the Aspartic acid at position 189 to Alanine (D189A) in GAPDH blocked its cleavage by caspase-1. In vivo, in a mice model of septic shock, characterized by hyperactivation of caspase-1, we observed depletion of the full-length forms of these glycolysis enzymes in the diaphragm muscle. Further studies in caspase-1 deficient mice will confirm whether this depletion, in caspase-1 proficient mice, was due to caspase-1 processing of the glycolysis enzymes. This provides a direct link between caspase-1 activation and inhibition of glycolysis, which might have important implications on loss of muscle contractility in septic shock.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Vita. Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M. Sc.)--Carleton University, 1988. / Also available in electronic format on the Internet.

No description available.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13067号 / 論医博第2122号 / 新制||医||1019(附属図書館) / 33218 / (主査)教授 長船 健二, 教授 松田 道行, 教授 岩井 一宏 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

No description available.

Fresh turkey meat color is influenced by a myriad of biological factors which include muscle fiber type composition and heme protein concentrations. These factors either contribute to or are subject to the biochemical events involved in the conversion of muscle to meat. Subtle deviations in the processing environment can also result in aberrant fresh meat quality development and may ultimately alter the quality characteristics of cooked product. Our objective was to describe the underlying cause and significance of two-toning in fresh turkey breast. In the first experiment, pectoralis muscles were collected and subjected to image processing software to describe color of fresh turkey. In the second experiment, shackling time was tested as an aggravator of fresh turkey color. Results showed turkey breast possess two-lobes that differ in pH, drip loss, energy metabolism and muscle fiber type composition. Results also showed fresh turkey color was enhanced during the time from stun to exsanguination (P < 0.05). These results suggest inherent differences in breast muscle are responsible for variations in fresh turkey color. / Master of Science

Part I: A remarkable feature of life on Earth is that despite the apparent observed diversity, the underlying chemistry that powers it is highly conserved. From the level of the nucleobases, through the amino acids and proteins they encode, to the metabolic pathways of chemical reactions catalyzed by these proteins, biology often utilizes identical solutions in vastly disparate organisms. This universality is intriguing as it raises the question of whether these recurring features exist because they represent some truly optimal solution to a given problem in biology, or whether they simply exist by chance, having arisen very early in life's history. In this project we consider the universality of metabolism { the set of chemical reactions providing the energy and building blocks for cells to grow and divide. We develop an algorithm to construct the complete network of all possible biochemically feasible compounds and reactions, including many that could have been utilized by life but never were. Using this network we investigate the most highly conserved piece of metabolism in all of biology, the trunk pathway of glycolysis. We design a method which allows a comparison between the large number of alternatives to this pathway and which takes into account both thermodynamic and biophysical constraints, finding evidence that the existing version of this pathway produces optimal metabolic fluxes under physiologically relevant intracellular conditions. We then extend our method to include an evolutionary simulation so as to more fully explore the biochemical space. Part II: Studies of population dynamics have a long history and have been used to understand the properties of complex networks of ecological interactions, extinction events, biological diversity and the transmission of infectious disease. One aspect of these models that is known to be of great importance, but one which nonetheless is often neglected, is spatial structure. Various classes of models have been proposed with each allowing different insights into the role space plays. Here we use a lattice-based approach. Motivated by gene transfer and parasite dynamics, we extend the well-studied contact process of statistical physics to include multiple levels. Doing so generates a simple model which captures in a general way the most important features of such biological systems: spatial structure and the inclusion of both vertical as well as horizontal transmission. We show that spatial structure can produce a qualitatively new effect: a coupling between the dynamics of the infection and of the underlying host population, even when the infection does not affect the fitness of the host. Extending the model to an arbitrary number of levels, we find a transition between regimes where both a finite and infinite number of parasite levels are sustainable, and conjecture that this transition is related to the roughening transition of related surface growth models.

Thesis (MSc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Having caused the deaths of more than 10 million individuals since 2000 with most of them occurring in Africa, malaria remains a serious disease that requires undivided attention. To this end a detailed kinetic model of Plasmodium falciparum glycolysis was constructed, validated and used to determine potential drug targets for the development of novel, effective antimalarial therapies. The kinetic model described the behaviour of the glycolytic enzymes with a set of ordinary differential equations that was solved to obtain the steady state fluxes and concentrations of internal metabolites. The model included a glycerol branch represented in a single fitted equation. This present study set out to detect, characterise, and incorporate into the model the enzymes that constitute the glycerol branch of P. falciparum glycolysis. The kinetic parameters of glycerol 3-phosphate dehydrogenase (G3PDH), the first enzyme in the branch and catalyst of the dihydroxyacetone phosphosate (DHAP) reducing reaction, was determined and added to the detailed kinetic model. The model was subsequently validated by comparing its prediction of steady state fluxes with experimentally measured fluxes. Once it was evident that the predictions of the unfitted model agreed with experimentally measured fluxes, metabolic control analysis was performed on this branched system to ascertain the distribution of control over the steady state flux through the glycerol branch. The control G3PDH exercised over its own flux was less than expected due to the enzyme’s sensitivity to changes in NADH and thus the redox balance of the cell. Attempts were made to detect the enzymes responsible for the conversion of glycerol 3-phosphate (G3P) to glycerol. Very low levels of glycerol kinase activity was observed. Although G3P-dependent release of inorganic phosphate was detected results were inconclusive as to whether a non-specific phosphatase also mediated the conversion. Overall, the expansion of the model to include G3PDH did not affect the steady state metabolite concentrations and flux adversely. / AFRIKAANSE OPSOMMING: Vanaf die jaar 2000 het malaria die dood van meer as 10 miljoen mense veroorsaak. Die meeste sterftes het in Afrika voorgekom —’n aanduiding van hoe ernstige siekte dit is en een wat onverdeelde aandag moet geniet. Om hierdie rede is ’n gedetaileerde kinetiese model van glikoliese in Plasmodium falciparum gebou, gevalideer en gebruik om potensiële dwelm teikens te identifiseer vir die ontwikkeling van nuwe, meer effektiewe anti-malaria terapieë. Die kinetiese model beskryf die gedrag van die glikolitiese ensieme in terme van gewone differensiële vergelykings wat opgelos is om die bestendige toestand fluksies en interne metaboliet konsentrasies te bepaal. Die model sluit ’n gliserol-tak in wat deur ’n enkele aangepaste vergelyking verteenwoordig word. Hierdie studie het voorgeneem om die ensieme van die gliserol-tak van P. falciparum glikoliese te identifiseer, karakteriseer en in die model te inkorporeer. Ons het die kinetiese parameters van die eerste ensiem in die gliserol-tak, gliserol 3-fosfaat dehidrogenase (G3PDH), die katalis van die dihidroksiasetoon fosfaat(DHAP) reduserende reaksie, bepaal. Die kinetiese parameters is by die gedetaileerde model gevoeg. Validering het plaasgevind deur die model se voorspellings met eksperimenteel bepaalde waardes te vergelyk. Toe dit duidelik geword het dat die voorspellings van die model met die eksperimenteel bepaalde fluks ooreenstem, is metaboliese kontrole analiese op die vertakte sisteem uitgevoer. Dit is gedoen om vas te stel hoe die bestendige toestand fluks deur die gliserol-tak beheer word. G3PDH het nie volle beheer oor sy eie fluks nie, in teenstelling met ons vergewagtinge. Daar is gepoog om vas te stel watter ensieme verantwoordelik is vir die produksie van gliserol vanuit gliserol 3-fosfaat (G3P). ’n Lae gliserolkinase aktiwiteit is waargeneem. Alhoewel G3P afhanklike vrystelling van anorganise fosfaat waargeneem is, is dit nie duidelik vanuit die resultate of die proses deur ’n nie-spesifieke fosfatase uitgevoer word nie. Die uitbreiding van die model om ’n G3PDH vergelyking in te sluit het nie die bestendige toestand metaboliet konsentrasies en fluks negatief geaffekteer nie.