Establishing the Relationship Between Function and Dynamics Within the Gated Mechanism of D-arginine Dehydrogenase

Enzymes are ubiquitous in biological systems. They catalyze chemical reactions and are involved in many biochemical processes. The enzyme of interest is Pseudomonas aeruginosa D-arginine dehydrogenase (PaDADH). This flavin-dependent enzyme is composed of approximately 375 amino acid residues and has a broad substrate specificity with D-amino acids. A water recognition motif, observed in roughly 1200 non-redundant protein data bank (PDB) structures, was revealed to be embedded near the active site of PaDADH. This motif coincides with the conformational changes of the enzyme’s gated mechanism. Molecular dynamics simulations were carried out to study the gated properties and structural characteristics of PaDADH in solution. Single amino acid mutations were undertaken to further understand the dynamics of the gated mechanism of this enzyme. In addition, pKa,shift analyses were evaluated to probe for the basic catalytic amino acid residue that is suggested to trigger the catalytic mechanism of PaDADH

The Epic of 1804 : based upon and incorporating an English translation of Maurice A. Sixto\u27s J\u27ai venge la race

This thesis is a play written in English based upon the French audio recording entitled J\u27ai venge la race by Maurice A. Sixto, famed Haitian story teller, comedian, diplomat and language professor (1919-1984). Mr. Sixto is regarded in Haitian literature as an oratory genius for his uncanny ability to analyze every segment of Haitian society using a rich and prolific narrative. With humor, wisdom, and a deft understanding of Haitian societal norms, he used his iconic voice to create authentic characters that have become part of the Haitian cultural fabric. His stories exposed the ills plaguing 20th century Haitian society; everything from the psychological remnants of slavery, to class differentiation and discrimination, to the attachment to the French language versus the use of Haitian Creole in bureaucratic and academic arenas, and beyond. As it is written, the play is in keeping with the Haitian literary tradition of a narrative within a narrative style of storytelling that Sixto uses in J\u27ai venge la race. The play also does not support a fixed chronological canon, leaving its conclusion without closure and open to speculation. Thematically, the play is polymorphous, its themes ranging from the supernatural, to historical criticism, to personal testimony, to mysticism, to sex

She said plain, burned things : A Feminist Poetics of the Unsayable in Twentieth Century Literary & Visual Culture

This dissertation examines the way silence, blank space, and other forms of creative withholding attempt to translate the unsayable, or to convey the unsayability of language in artistic form. Through a study of the works of Sylvia Plath, Jean Rhys, Rachel Zucker, Marguerite Duras, Anne Carson, and visual images, this work observes the connection between women\u27s writing in the 20th century and the communication of painful subject matter through attention to absence. This study attends explicitly to how formal qualities in artistic works attend to ontological concerns through an examination of the intersection of concerns with phenomenology, feminism, and formal aesthetics

Microbial diversity studies of the porcine gastrointestinal ecosystem during weaning transition

At the time of weaning, major quantitative and qualitative changes occur in the composition of the intestinal microbiota of piglets, influenced by diet, environmental factors, and the host. Within a short period of time, the intestinal microbiota must ultimately develop from a simple, unstable community into a complex and stable one. Here we present data on the development of the intestinal microbiota based on 16S rRNA gene sequence diversity. In addition to a PCR-based analysis of the 16S rRNA gene by cloning and denaturing gradient gel electrophoresis (DGGE), data on fluorescent in situ hybridisation (FISH) are presented to quantify the total bacterial communities, major Lactobacillus populations and specific Lactobacillus species. The results reported here indicate that the addition of non-digestible, fermentable carbohydrates (= prebiotics) leads to an enrichment of lactobacilli in the small intestine, and increased stability and diversity of the bacterial community in the colon. The data support the hypothesis that changes of the diet can modulate the composition of the microbiota in the intestine. These findings may have potentially major implications for the development of dietary strategies aiming to improve animal health during the weaning process

Media Coverage of Muslim Devotion: A Four-Country Analysis of Newspaper Articles, 1996–2016

Scholars have identified Muslims’ religiosity and faith practices, often believed to be more intense than those of other religious groups, as a point of friction in liberal democracies. We use computer-assisted methods of lexical sentiment analysis and collocation analysis to assess more than 800,000 articles between 1996 and 2016 in a range of British, American, Canadian, and Australian newspapers. We couple this approach with human coding of 100 randomly selected articles to investigate the tone of devotion-related themes when linked to Islam and Muslims. We show that articles touching on devotion are not as negative as articles about other aspects of Islam—and indeed that they are not negative at all, on average, when focused on a key subset of devotion-related articles. We thus offer a new perspective on the perception of Islamic religiosity in Western societies. Our findings also suggest that if newspapers strive to provide a more balanced portrayal of Muslims and Islam within their pages, they may seek opportunities to include more frequent mentions of Muslim devotion

Investigations on ileal microbial flora in weaning piglets

To characterize ileal microbial flora in weaning piglets a slaughter trial was conducted. 224 German Landrace piglets of both genders were allocated to four different feeding regimes (with or without avilamycin, 3 resp. 8 % crude fibre content). At predefined times pre- and postweaning piglets were sacrificed, the whole intestinal tract was removed and its content collected separately for each section. The microbial community was examined applying classical plate counting (selective agar plates) and molecular techniques (DGGE, 16SrDNA-sequencing). Furthermore a range of microbial metabolites was determined. Changes in ileal microflora ¿ rather due to age than to diet - were observed pre- and postweaning

Endogenous amino acid flow in the avian ileum: quantification using three techniques

The aim of the present study was to compare the protein-free diet, guanidinated casein (GuC) and enzyme hydrolysed casein (EHC) methods for the quantification of endogenous amino acid (AA) flow in the avian ileum. Growing broiler chickens (5 weeks old) were used. All three assay diets were based on dextrose, and in the GuC and EHC diets GuC or EHC were the sole source of N. Endogenous AA flows determined with the use of protein-free diet were considerably lower (P 0.05), except for the flow of arginine, which was lower (P < 0.05) in the EHC method. Glutamic acid, aspartic acid, threonine and glycine were the predominant endogenous AA present in digesta from the distal ileum. The contents of methionine, histidine and cystine were lower compared with other AA. The method of determination had no effect on the AA composition of endogenous protein, except for threonine, glutamic acid, lysine, arginine and cystine. The concentrations of threonine and arginine were lower (P < 0.05) and that of lysine was higher (P < 0.05) with the EHC method compared with the other two methods. The concentration of glutamic acid was greater (P < 0.05) and that of cystine was lower (P < 0.05) in the EHC and GuC methods compared with the protein-free diet method. The results showed that the ileal endogenous flows of N and AA are markedly enhanced by the presence of protein and peptides, above those determined following feeding of a protein-free diet. It is concluded that the use of EHC and GuC methods enables the measurement of ileal endogenous losses in chickens under normal physiological conditions

Physiological Concentration of Exogenous Lactate Reduces Antimycin A Triggered Oxidative Stress in Intestinal Epithelial Cell Line IPEC-1 and IPEC-J2 In Vitro

Weaning triggers an adaptation of the gut function including luminal lactate generation by lactobacilli, depending on gastrointestinal site. We hypothesized that both lactobacilli and lactate influence porcine intestinal epithelial cells. In vivo experiments showed that concentration of lactate was significantly higher in gastric, duodenal and jejunal chyme of suckling piglets compared to their weaned counterparts. In an in vitro study we investigated the impact of physiological lactate concentration as derived from the in vivo study on the porcine intestinal epithelial cells IPEC-1 and IPEC-J2. We detected direct adherence of lactobacilli on the apical epithelial surface and a modulated F-actin structure. Application of lactobacilli culture supernatant alone or lactate (25 mM) at low pH (pH 4) changed the F-actin structure in a similar manner. Treatment of IPEC cultures with lactate at near neutral pH resulted in a significantly reduced superoxide-generation in Antimycin A-challenged cells. This protective effect was nearly completely reversed by inhibition of cellular lactate uptake via monocarboxylate transporter. Lactate treatment enhanced NADH autofluorescence ratio (F-cytosol/F-nucleus) in non-challenged cells, indicating an increased availability of reduced nucleotides, but did not change the overall ATP content of the cells. Lactobacilli-derived physiological lactate concentration in intestine is relevant for alleviation of redox stress in intestinal epithelial cells.Peer reviewe