Carboxyl esterases, particularly arylesterases, were predicted from 16 microbial genomes, and then expressed in E. coli. Of the more than 175 cloned genes, 86 were expressed in soluble form. These were screened for activity using a range of both commercial and natural substrates. Forty-eight proteins were active on pNP-acetate at pH 8 whereas 38 proteins did not exhibit any activity towards any substrates. Among the 48 active proteins, 20 proteins showed arylesterase activity. To date, 8 bacterial esterases and 2 archaeal arylesterases were characterized in terms of pH stability and optima, thermal inactivation, solvent stability, and kinetics. To our knowledge there is only one other published report of arylesterases from archaea. The synthetic capability of arylesterases can transform phenolic acids to value-added chemicals. Accordingly, this project provides an arsenal of industrially significant activities that can extend the antioxidant properties of lignin-derived molecules in a broader range of renewable products.

Made available in DSpace on 2014-06-11T19:35:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-30Bitstream added on 2014-06-13T20:26:17Z : No. of bitstreams: 1 zanella_lf_dr_botfmvz.pdf: 531665 bytes, checksum: c547ec20928912c591261203344c53d9 (MD5) / Universidade Estadual Paulista (UNESP) / Os líquidos fetais possuem diversas funções que são vitais para o feto. Para a espécie eqüina até o presente momento, não está totalmente definida a composição bioquímica do líquido amniótico no decorrer da gestação. O presente trabalho teve como objetivo verificar a composição bioquímica do liquido amniótico e alantoideano das éguas em diferentes fases da gestação. Para isso analisou-se 60 amostras de fluidos fetais, empregando-se kits comerciais para se determinar a concentração bioquímica da Fosfatase Alcalina, Glicose, Proteínas Totais, Uréia, Creatinina, Cálcio, Cloreto, Sódio e Potássio durante a gestação. A concentração da alfa-fetoproteína foi avaliada empregando-se a eletroforese em gel de poliacrilamida. A concentração da Fosfatase Alcalina no liquido amniótico foi maior quando comparada ao liquido alantoideano nas três fases da gestação (p < 0,05). Para a glicose o valor médio entre os dois fluidos não apresentou variações (p < 0,05). Para a Proteína total o valor médio do liquido amniótico foi maior que o alantoideano (p < 0,05). A Uréia sofreu variações na concentração entre as fases, mas não há diferenças dos valores médios (p > 0,05) entre os fluidos. Para a Creatinina os valores presentes no liquido alantoideano são mais altos que os valores do liquido amniótico (p < 0,05). As concentrações dos íons Cloreto e Sódio apresentaram–se mais elevados (p < 0,05) no liquido amniótico. As concentrações dos íons Cálcio e Potássio foram mais elevadas nos líquidos alantoideanos (p<0,05). A eletroforese identificou duas bandas protéicas que podem ser a alfa-fetoproteína, ela parece aumentar a concentração durante o período gestacional. Porém, faltam estudos na espécie eqüina para a comparação dos resultados do presente trabalho. / Fetal fluids play a vital role in the development of the fetus. The biochemical composition of the amniotic fluid along pregnancy in horses had not been described until this present study. Sixty samples of fetal fluids were collected and the concentrations of Alkaline Phosphatase (FA), Glucose, Total Proteins (PT), Urea, Creatinin, Calcium (Ca), Chloride (Cl), Sodium (Na) and Potassium (K) along pregnancy were determined using commercially available kits. The levels of alpha-fetoprotein (AFT) were measured by polyacrylamide gel electrophoresis. During the three stages of pregnancy the concentrations of FA in the amniotic fluid were higher than those determined in the allantoic fluid (p < 0,05). The glucose levels did not differ between the fluids (p < 0,05). The mean values for the concentrations of PT were higher in the amniotic fluid than in the allantoic (p < 0,05). The urea levels differ among the pregnancy stages, but there were no differences in the mean values of urea (p > 0,05) between the two fluids. The concentrations of creatinin obtained in the allantoic fluid were higher than those obtained in the amniotic fluid (p < 0,05). The concentrations of Cl and Na were elevated (p < 0,05) in the amniotic fluid. The levels of the ions Ca e K were higher in the allantoic fluid (p<0,05). Polyacrylamide gel electrophoresis identified two protein bands that could be alpha-fetoprotein, which appears to have its concentration increased during pregnancy. There is a need for more studies in the biochemical composition of fetal fluids in horses to compare the results obtained in this study.

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Microalgae have been so far identified as the major producers of organic matter through their photosynthetic activities. In the present work, Nannochloris sp. and Amphora sp., two marine microalgae, have been investigated for proteins and lipids production. Protein fraction was quantified using Bicinchoninic acid (BCA) assay. Protein content in Nannochloris sp. was 16.69 ±4.07 % of dry mass and in Amphora sp. it was 39.89 ±2.09 % of dry mass. Enzyme assays were conducted spectrophotometrically. Nannochloris sp. had malate dehydrogenase, peroxidase and catalase activities. Amphora sp. exhibited malate dehydrogenase, catalase and cytochrome C oxidase activities. These enzymes have several valuable applications in some metabolic pathways and as antioxidant nutrition additives. Besides, lipid extraction was conducted using methanol/ chloroform solvent extraction. Crude lipid extract was analyzed using gas chromatography-mass spectrometry. Lipid contents were 8.14 ±3.67 % in Nannochloris sp. and 10.48 ±1.26% on dry basis in Amphora sp., respectively. Nannochloris sp. fatty acids were composed of C16:0 and C18:0 that are valuable for biodiesel production, and É-3 C18:3, É-6 C18:2, É-6 C16:2 having great nutritional values. In Amphora sp., the fatty acids consisted of C14:0, C16:0 and C16:1 shown to be valuable for biodiesel production and É-3 C22:6 having high nutritional values. Furthermore, a single step conversion of microalgal oil to fatty acid methyl esters was carried out starting directly from lyophilized microalgae. This promising process, in situ transesterification, led to better yields of methyl esters as compared to conventional lipid extraction followed by separate transesterification. / Master of Science

In all kinds of disease models, many proteins involved in protein-protein interactions (PPIs) are mutated and do not function properly. The important role of PPIs in disease makes the design of small molecule inhibition an interesting proposition. This project looks at mouse double minute 2 (MDM2) and mouse double minute X (MDMX) which binds and inhibits the tumour suppressor protein p53. MDM2 and MDMX are therefore attractive therapeutic targets due to their role in tumour progression. The aim is to identify small molecule dual inhibitors that are able to disrupt MDM2 and MDMX from binding to p53. Both N-terminal MDM2 and MDMX were successfully expressed and purified with high purity and decent yield. These proteins were used to develop Fluoresence Polarization (FP) and Capillary Electrophoresis (CE) assays for small molecule inhibitors screening. This work has successfully developed FP and CE assays for detecting weakly interacting fragments. The CE assay is a novel method for detecting weak fragments for protein-protein interactions, which are a challenging target. Two approaches were employed to identify small molecule inhibitors for MDM2- N/p53 interaction. At first, small molecules were identified using in silico screening and these hits were verified using FP and CE assays. Second, analogue exploration was applied to identify fragments from the small molecule inhibitors discovered from the in silico screening. Diphenylamine and oxindole fragments were identified as the most potent. However, diphenylamine fragment was discovered to aggregate MDM2-N and was ranked as a false positive hit. No protein aggregation was found when incubated with the oxindole fragment. Therefore oxindole can provide a good starting point for the design of higher affinity analogues. Studying the interaction of MDMX has only recently been undertaken. MDMX contains a high homology binding site with MDM2. Hence, developing a dual MDM2/MDMX inhibitor has become an attractive target to focus on. FP and CE assays were developed to screen compounds against MDMX-N. In silico screening against MDM2-N and MDMX-N found several hits. One compound was discovered as a dual binder to MDM2-N and MDMX-N with low μM affinity. This novel hit is potentially a good starting point for the design of higher affinity analogues.

Chronic pain and excessive alcohol consumption are individually problems in our society today. Alcohol Use Disorder (AUD) affects 15.1 million adult Americans each year. Chronic pain affects over 100 million people annually in the United States. However, there is growing evidence suggesting that these two conditions can often be interrelated with chronic pain increasing consumption of alcohol, and excessive alcohol consumption increasing pain that leaves a feedback cycle trapping millions of patients in an ever worsening spiral. Large population-based studies show an association between pain and alcohol abuse, suggesting a link between increased alcohol use and reduced pain. While rodent studies consistently demonstrate antinociception following acute ethanol administration in hot-plate and tail-flick tests. However, little is currently known about the effects of alcohol in chronic pain models. We hypothesize that acute ethanol administration will possess analgesic-like properties in models of chronic pain by engaging opioid receptors in addition to its more commonly studied action at the GABA receptor. The first aim of this study was to characterize the antinociceptive effects of alcohol in Complete Freund’s Adjuvant (CFA) and Chronic Constriction Injury (CCI) mouse models of chronic inflammatory and neuropathic pain models, respectively. The second aim of this study is to investigate the mechanisms behind ethanol's analgesic like effects including tolerance, receptor activation and correlates with blood alcohol content. Lastly, we investigated whether alcohol maintains its analgesic-like effects in non-reflexive assays in addition to effects in reflexive assays.

Spurred by a host of beneficial uses, the global use of nanoparticles is rapidly growing. Silver nanoparticles (Ag NPs) are used widely in consumer products, medicine, and the semiconductor industry. As nanoparticles become more commonly used, the transport of nanoparticles into the environment might negatively affect microorganisms in natural and engineered systems. The effects of Ag NPs on microorganisms have primarily been studied in planktonic or free-swimming cultures, but little work has been done to look at biofilm susceptibility to Ag NPs. This thesis describes bacterial tolerance, or the ability of an organism to survive exposure to an insult, to Ag NPs. The tolerance of planktonic and biofilm cells of the common wastewater treatment bacterium Zoogloea ramigera and a Rhodococcus strain isolated from drinking water was tested. These bacteria were exposed to different concentrations of Ag NPs, ranging from 0 to 25 mg/L, for a period of 5 hours. Results showed decreased tolerance with increasing Ag NP concentrations for both bacterial species. Z. ramigera biofilm cells are slightly more tolerant to Ag NPs than are planktonic cells. On the other hand, Rhodococcus planktonic and biofilm cells exhibit similar tolerance. However, in both cases, biofilm cells do not exhibit a striking protective effect against Ag NPs as compared to planktonic cells. This study shows that even short-term insults with Ag NPs can affect bacteria in engineered systems. A preliminary study of the shedding of free silver ions as a possible mechanism of Ag NP toxicity demonstrated that free silver ions were toxic to Escherichia coli in a 0.14M chloride environment. The data suggest that free silver ions can be pulled into solution from Ag NPs in chloride environments via ligand-promoted dissolution. Further work is needed to examine the antibacterial mechanism of Ag NPs against planktonic and biofilm cells to better understand how the release of nanoparticles into the environment can affect microorganisms in natural and engineered water systems. / text

The ability to rationally or randomly modify proteins has expanded their employment in various bioanalytical applications. The bioluminescent protein, aequorin, has been employed as a reporter for decades due to its simplistic, non-hazardous nature and its high sensitivity of detection. More recently aequorin has been subject to spectral tuning. Techniques such as random and site-directed mutagenesis, the incorporation of coelenterazine analogues and the incorporation of non-natural amino acids have expanded the palette of aequorin by altering their emission wavelengths and/or half-lifes. Due to the increased diversity of aequorin, it can be used in multianalyte detection. Although aequorin has been studied extensively and has been used as a reporter in a wide array of applications, it has never been employed as a reporter in systems that involve the splitting of aequorin. Herein we describe the splitting of aequorin in such a way where it becomes the reporter protein in the development of protein-based molecular switches. We have created two distinct protein switches by genetically inserting the glucose-binding protein and the sulfate-binding protein into the aequorin sequence, splitting it in such a manner that it allows for the selective detection of glucose and sulfate, respectively. In a separate investigation, we developed a bioluminescence inhibition binding assay for the detection of hydroxylated polychlorinated biphenyls. These systems have shown that they can be employed in the detection of the respective analyte in biological as well as in environmental samples, which demonstrated a sensitive, fast alternative approach to current methods for on-site screening. Furthermore, we propose the rational design, preparation and use of truncated aequorin fragments in bioanalytical platforms such as multi-analyte detection, protein complementation assays and protein tagging assays based on our discovery that truncated aequorin retains partial bioluminescence emission. One such truncated aequorin demonstrated a large red shift in the emission maximum. It is envisioned that this new red-shifted truncated aequorin will find applications in multi-analyte detection. We anticipate that this work will lead to the discovery of additional functional truncated aequorin fragments that can be employed in novel protein-protein interactions or protein folding systems.