Este trabalho apresenta estudos bioanalíticos envolvendo a bactéria Xylella fastidiosa. A X. fastidiosa é uma bactéria aeróbica, responsável pela doença Clorose Variegada dos Citros. Durante o projeto genoma foi possível mapear diversas proteínas, sendo uma das enzimas a hidroxinitrila liase (HNL). As indústrias de química fina, em especial a farmacêutica, vêm utilizando enzimas para produção de enantiômeros que visam à formação de novas drogas quirais com alto teor de pureza. As enzimas HNLs são proteínas presentes na superfamília α/β-hidrolases, da qual também fazem parte as lipases e esterases. As hidroxinitrilas são empregadas na síntese de compostos quirais, para melhores condições em biocatálise. HNLs são enzimas que catalisam a formação reversível de cianoidrinas utilizando ácido cianídrico (HCN) e aldeídos ou cetonas. Por esta razão, foi analisado o potencial de biocatálise enantiosseletiva da XfHNL referente ao substrato (R,S)-ibuprofeno e a síntese do éster racêmico, α-metil benzil acetato, e também a síntese de cianoidrinas catalisadas pela XfHNL. Pelas três reações estudadas neste trabalho foi possível observar que XfHNL não possui enantiosseletividade em dois dos substratos testados. Também foi estudado neste trabalho a expressão proteica nos meio de cultura líquidos XDM2, XDM4 e XDM5 até então não estudados por eletroforese OFFGEL, uma nova plataforma semi-preparativa para fracionamento de proteínas. Foi realizado um estudo preliminar desse meios, para avaliar a expressão proteica, e também o meio de cultura BCYE para visualizar possíveis fatores sinal difusível (DSF) por espectrometria de massas e seu comportamento em eletroforese capilar. Por fim, foi fabricado um microdispositivo de microfluídico feito em poliéster-toner (PT) para biomimetizar o xilema para o estudo in vitro de X. fastitiosa e seu comportamento na colonização. Assim sendo, foi possível visualizar o crescimento, a formação de biofilme e a presença de goma xantana dentro do microchip. / This work involves bioanalytical studies of Xylella fastidiosa. The X. fastidiosa is an aerobic bacteria, responsible for the disease Citrus Variegated Chlorosis. During the genome project was possible to characterize several proteins, one of the enzymes hydroxynitrila lyase (HNL). Industries, especially pharmaceuticals, have been using enzymes for production of enantiomers aimed at the formation of new chiral drugs with high purity. Enzymes are proteins present in HNLs superfamily α / β-hydrolases, which are also part of lipases and esterases. The HNLs have been employed in the synthesis of chiral compounds for better conditions in biocatalysis. HNLs are enzymes that catalyze the reversible formation of cyanohydrins using hydrocyanic acid (HCN) and aldehydes or ketones. For this reason, we investigated the potential of enantioselective biocatalysis of XfHNL respect to substrate (R,S)-ibuprofen and synthesis of racemic ester, α-methyl benzyl acetate. Also, the synthesis of cyanohydrins catalyzed by XfHNL. By three reactions involved in this work, it was observed that there were not XfHNL enantioselectivity in 2 of the substrates studied. Also, it was studied protein expression in liquid culture medium XDM2, XDM4 and XDM5 hitherto studied by electrophoresis OFFGEL, a new platform for semi-preparative protein fractionation. We conducted a quick study and through this liquid medium, BCYE, to view possible DSFs by mass spectrometry and their behavior in capillary electrophoresis. And finally, it was produced a PT microdevice in order to mimic the xylem vessels to study of X. fastitiosa in vivo and its behavior. Accordingly, it is possible to display the growth, biofilm formation and the presence of xanthan gum in the microchip.

The term 'club drug' can be loosely defined as any substance used to enhance social settings. Such drugs are commonly found at raves or similar all-night dance parties and include methamphetamine, 3,4-methylenedioxymethamphetamine, gamma-hydroxybutyrate (GHB), ketamine (KET), and flunitrazepam (FLU). These drugs have potentially dangerous side effects including hallucinations, paranoia, amnesia and hyperthermia. In addition, GHB, KET and FLU are considered predatory drugs due to their roles in drug-facilitated sexual assault. Forensic and regulatory agencies routinely have the need for determination and accurate quantification of these drugs in biological fluids, especially in cases of mortality or criminal investigations. This review presents the chromatographic and spectroscopic methods published for such analyses over the last decade, including sample preparation techniques and validation data.

The thickness shear mode acoustic wave (TSM) sensor, operated in a flow-through format, has been widely used in bioanalytical research. My research is mainly focused on the study of surface-attached biomolecules and cells using the TSM sensor, including lesions in DNA, conformational change of calmodulin, as well as the properties and attachment of rat aortic smooth muscle cells. Aldehydic apurinic or apyrimidinic sites (AP sites) that lack a nucleobase moiety are one of the most common forms of toxic lesions in DNA. In this work, synthesized oligodeoxyribonucleotides containing one, two, or three abasic sites were hybridized to complementary sequences immobilized on the gold electrode of the TSM device by affinity binding. The influence of AP sites on local base stacking energy and geometry caused a dramatic destabilization of the DNA duplex structure, which was detected by the TSM sensor. The signals detected by TSM correlated well with the thermostability of DNA duplexes in solution. The results indicate that both the number of sites and their localization in the double-stranded structure influence the stability of a 19 b.p. duplex. TSM was also used to detect the binding of ions or peptides to surface-attached calmodulin. The interaction between calmodulin and ions induced an increase in resonant frequency and a decrease in motional resistance. In addition, these signal changes were reversible upon washing with buffer. The response was interpreted as a decrease in surface coupling induced by exposure of hydrophobic domains on the protein, and an increase in the length of calmodulin by approximately 3 Å. In addition, the interaction of the protein with peptide together with calcium ions was detected successfully, despite the relatively low molecular mass of the 2-kDa peptide. In addition, the attachment of smooth muscle cells to various surfaces has been monitored by TSM. These surfaces include laminin, fibronectin and bare gold. The results of these experiments in terms of changes of frequency (fs) and resistance (Rm) were analyzed. The responses of the surface-bound cells to the introduction of various ions, depolarisation events and damage subsequent to exposure to hydrogen peroxide were also observed. Morphological changes in the cells, as confirmed by atomic force microscopy and scanning electron microscopy, are correlated with results from the TSM sensor.

The thickness shear mode acoustic wave (TSM) sensor, operated in a flow-through format, has been widely used in bioanalytical research. My research is mainly focused on the study of surface-attached biomolecules and cells using the TSM sensor, including lesions in DNA, conformational change of calmodulin, as well as the properties and attachment of rat aortic smooth muscle cells. Aldehydic apurinic or apyrimidinic sites (AP sites) that lack a nucleobase moiety are one of the most common forms of toxic lesions in DNA. In this work, synthesized oligodeoxyribonucleotides containing one, two, or three abasic sites were hybridized to complementary sequences immobilized on the gold electrode of the TSM device by affinity binding. The influence of AP sites on local base stacking energy and geometry caused a dramatic destabilization of the DNA duplex structure, which was detected by the TSM sensor. The signals detected by TSM correlated well with the thermostability of DNA duplexes in solution. The results indicate that both the number of sites and their localization in the double-stranded structure influence the stability of a 19 b.p. duplex. TSM was also used to detect the binding of ions or peptides to surface-attached calmodulin. The interaction between calmodulin and ions induced an increase in resonant frequency and a decrease in motional resistance. In addition, these signal changes were reversible upon washing with buffer. The response was interpreted as a decrease in surface coupling induced by exposure of hydrophobic domains on the protein, and an increase in the length of calmodulin by approximately 3 Å. In addition, the interaction of the protein with peptide together with calcium ions was detected successfully, despite the relatively low molecular mass of the 2-kDa peptide. In addition, the attachment of smooth muscle cells to various surfaces has been monitored by TSM. These surfaces include laminin, fibronectin and bare gold. The results of these experiments in terms of changes of frequency (fs) and resistance (Rm) were analyzed. The responses of the surface-bound cells to the introduction of various ions, depolarisation events and damage subsequent to exposure to hydrogen peroxide were also observed. Morphological changes in the cells, as confirmed by atomic force microscopy and scanning electron microscopy, are correlated with results from the TSM sensor.

In this thesis, cyclic biamperometry (CB) as a new method in electrochemistry, has been introduced and investigated. The hallmark of this method is the absence of a reference electrode which potentially allows simplification and miniaturization of the measurement apparatus. Similarities and differences of this method and cyclic voltammetry (CV) have been studied and it was shown that under conditions of using standard electrodes, CB has a better sensitivity and a lower detection limit than CV. A new equivalent circuit model for the cell has been proposed and parameters affecting the sensitivity of CB, such as keeping the concentration of one redox species in excess and having a larger W2 electrode, have been described. The redox cycling effect in biamperometric systems has been investigated and it is shown that improvements of at least two orders of magnitude in sensitivity can be achieved by using interdigitated electrodes (IDEs). In addition, an example for applications of this method, including biamperometric dead-stop titration of 1-naphthol with ferricyanide, has been presented and possible fields in which CB can be incorporated (e.g. monitoring the activity of alkaline phosphatase) have been illustrated. Finally, a few suggestions for future studies and further improvements have been outlined.

In this thesis, cyclic biamperometry (CB) as a new method in electrochemistry, has been introduced and investigated. The hallmark of this method is the absence of a reference electrode which potentially allows simplification and miniaturization of the measurement apparatus. Similarities and differences of this method and cyclic voltammetry (CV) have been studied and it was shown that under conditions of using standard electrodes, CB has a better sensitivity and a lower detection limit than CV. A new equivalent circuit model for the cell has been proposed and parameters affecting the sensitivity of CB, such as keeping the concentration of one redox species in excess and having a larger W2 electrode, have been described. The redox cycling effect in biamperometric systems has been investigated and it is shown that improvements of at least two orders of magnitude in sensitivity can be achieved by using interdigitated electrodes (IDEs). In addition, an example for applications of this method, including biamperometric dead-stop titration of 1-naphthol with ferricyanide, has been presented and possible fields in which CB can be incorporated (e.g. monitoring the activity of alkaline phosphatase) have been illustrated. Finally, a few suggestions for future studies and further improvements have been outlined.

As the move towards the miniaturization of many diagnostic and detection systems continues, the need for increasingly versatile yet sensitive labels for use in these systems also grows. Luminescent reporters provide us with a solution to many of the issues at hand through their unique and favorable characteristics. Bioluminescent proteins offer detection at extremely low concentrations and no interference from physiological fluids leading to excellent detection limits, while the vast number of fluorescent proteins and molecules available allows the opportunity to select a tailored reporter for a specific task. Both provide relatively simply instrumentation requirements and have exhibited great promise with many of the miniaturized systems such as lab-on-a-chip and lab-on-a-CD designs. Herein, we describe the novel employment of luminescent reporters for four distinct purposes. First off, by combining both time and wavelength resolution we have expanded the multiplexing capabilities of the photoprotein aequorin beyond duel-analytes, demonstrating the ability to simultaneously detect three separate analytes. Three semi-synthetic aequorin proteins were genetically conjugated to three pro-inflammatory cytokines (interleukins 1, 6, and 8) resulting in aequorin labeled cytokines with differing emission maxima and half lives to allow for the simultaneous detection of all three in a single solution through the elevated physiological concentration range. Secondly a semi-synthetic aequorin variant has been genetically enhanced to serve as an immunolabel and exhibited the ability to sensitively detect the acute myeloid leukemia marker, CD33, down to the attomole level in addition to improving aequorin imaging capabilities. In the third example, the aequorin complex was rationally, genetically split into two parts and attached to the termini of the cAMP selective cAMP receptor protein (CRP) creating a genetically fused molecular switch. The conformational change experienced by CRP upon the binding of cAMP translates into a loss of bioluminescent signal from aequorin and has shown the ability to respond linearly to cAMP over several orders of magnitude. Lastly, through custom design, a reagentless, portable, fluorescent fiber optic detection system has been developed, capable of being integrated into the body through a heart catheter. The system was able to respond to changes in potassium concentration selectively, reproducibly and reversibly with a fast response time of one minute.

Este trabalho apresenta estudos bioanalíticos envolvendo a bactéria Xylella fastidiosa. A X. fastidiosa é uma bactéria aeróbica, responsável pela doença Clorose Variegada dos Citros. Durante o projeto genoma foi possível mapear diversas proteínas, sendo uma das enzimas a hidroxinitrila liase (HNL). As indústrias de química fina, em especial a farmacêutica, vêm utilizando enzimas para produção de enantiômeros que visam à formação de novas drogas quirais com alto teor de pureza. As enzimas HNLs são proteínas presentes na superfamília α/β-hidrolases, da qual também fazem parte as lipases e esterases. As hidroxinitrilas são empregadas na síntese de compostos quirais, para melhores condições em biocatálise. HNLs são enzimas que catalisam a formação reversível de cianoidrinas utilizando ácido cianídrico (HCN) e aldeídos ou cetonas. Por esta razão, foi analisado o potencial de biocatálise enantiosseletiva da XfHNL referente ao substrato (R,S)-ibuprofeno e a síntese do éster racêmico, α-metil benzil acetato, e também a síntese de cianoidrinas catalisadas pela XfHNL. Pelas três reações estudadas neste trabalho foi possível observar que XfHNL não possui enantiosseletividade em dois dos substratos testados. Também foi estudado neste trabalho a expressão proteica nos meio de cultura líquidos XDM2, XDM4 e XDM5 até então não estudados por eletroforese OFFGEL, uma nova plataforma semi-preparativa para fracionamento de proteínas. Foi realizado um estudo preliminar desse meios, para avaliar a expressão proteica, e também o meio de cultura BCYE para visualizar possíveis fatores sinal difusível (DSF) por espectrometria de massas e seu comportamento em eletroforese capilar. Por fim, foi fabricado um microdispositivo de microfluídico feito em poliéster-toner (PT) para biomimetizar o xilema para o estudo in vitro de X. fastitiosa e seu comportamento na colonização. Assim sendo, foi possível visualizar o crescimento, a formação de biofilme e a presença de goma xantana dentro do microchip. / This work involves bioanalytical studies of Xylella fastidiosa. The X. fastidiosa is an aerobic bacteria, responsible for the disease Citrus Variegated Chlorosis. During the genome project was possible to characterize several proteins, one of the enzymes hydroxynitrila lyase (HNL). Industries, especially pharmaceuticals, have been using enzymes for production of enantiomers aimed at the formation of new chiral drugs with high purity. Enzymes are proteins present in HNLs superfamily α / β-hydrolases, which are also part of lipases and esterases. The HNLs have been employed in the synthesis of chiral compounds for better conditions in biocatalysis. HNLs are enzymes that catalyze the reversible formation of cyanohydrins using hydrocyanic acid (HCN) and aldehydes or ketones. For this reason, we investigated the potential of enantioselective biocatalysis of XfHNL respect to substrate (R,S)-ibuprofen and synthesis of racemic ester, α-methyl benzyl acetate. Also, the synthesis of cyanohydrins catalyzed by XfHNL. By three reactions involved in this work, it was observed that there were not XfHNL enantioselectivity in 2 of the substrates studied. Also, it was studied protein expression in liquid culture medium XDM2, XDM4 and XDM5 hitherto studied by electrophoresis OFFGEL, a new platform for semi-preparative protein fractionation. We conducted a quick study and through this liquid medium, BCYE, to view possible DSFs by mass spectrometry and their behavior in capillary electrophoresis. And finally, it was produced a PT microdevice in order to mimic the xylem vessels to study of X. fastitiosa in vivo and its behavior. Accordingly, it is possible to display the growth, biofilm formation and the presence of xanthan gum in the microchip.

The data presented in this thesis highlights how sea water composition and biological activity can affect the morphology, composition, organic volume fraction, and hygroscopicity of individual sea spray aerosols (SSA). A variety of techniques were used to measure seawater and aerosol composition with the emphasis placed on spatial chemical composition obtained through Scanning Transmission X-ray Microscopy-Near Edge X-ray Absorption Fine Structure (STXM-NEXAFS). Through NEXAFS data, organic volume fractions were derived from Beer's Law, and spatially resolved chemical composition for individual particles were determined through application of singular value decomposition and principal component analysis. These methods were applied to two specific studies: a 30 day mesocosm study using a wave flume termed Investigation into Marine PArticle Chemistry and Transfer Science (IMPACTS) and a smaller scale collection of SSA generated from a miniature Marine Aerosol Reference Tank (mini-MART) with bacteria enriched sea water. For IMPACTS, two consecutive phytoplankton blooms were observed; however, organic enrichment in sea spray aerosols only occurred during one of the blooms. STXM-NEXAFS measurements revealed four distinct particle types: sea salt-organic particles with a distinct NaCl core and an organic carbon coating, homogenously mixed organic-inorganic particles, calcium-rich needle-like particles, and agglomerations of optically thick organic material with inorganic salts. Organic enrichment was correlated with aliphatic-rich organic species as detected by an intense Cls—•a(C-H)* exciton excitation. This enrichment was unique to particles collected in the aerodynamic size range 0.18-0.32 µm and corresponded with a depression in the hygroscopicity of small particles. This depression can significantly suppress the number of cloud condensation nuclei thus influencing cloud properties. Results of the mini-MART collection revealed that whole bacterial inclusions are ejected into SSA via jet drops. Bacterial inclusions are rich in protein and can be identified through Principal Component Analysis (PCA) on image stacks acquired at the carbon K edge. Vesicles were not identified in SSA but could be resolved in standard liquid cell samples in which they exhibited a strong phospholipid spectrum that could also be resolved spatially usually PCA coupled with k-means clustering. Bacterial inclusions in SSA may affect SSA physical properties by serving as ice nuclei.1,2,3

This dissertation expounds growing insight of the electrospray droplet ionization mechanism following ablation of dried hydrophobic and hydrophilic molecules using femtosecond laser pulses and mass analysis of the gas phase ions. Both hydrophobic and hydrophilic molecules were laser vaporized into an electrospray solvent opposite in polarity revealing appreciable ion intensity for all samples in contrast to ESI-MS and DESI measurements were solubility of the analyte in the spray solvent is a prerequisite. Quantitative analysis of equimolar protein solutions was established using LEMS reporting over three decades of quantitave response with little evidence of ion suppression. In contrast, ESI-MS measurements of similar equimolar protein solutions revealed severe ion suppression eliminating ion current from one of the protein analytes. Finally, the nature of an analyte following nonresonant laser vaporization has been the subject of debate. Aqueous trypsin was laser vaporized into an electrospray solvent containing either buffer or acid with substrate. LEMS measurements using buffer revealed enzyme-substrate intermediate charge states and continued enzymatic activity while the lack of enzyme-substrate intermediates and stymied enzymatic activity observed using acid suggests nonresonant laser vaporization preserves solution phase structure. This dissertation also extends considerably the use of LEMS for identification and characterization of energetic materials in their pre- and post-blast forms without sample preparation. The use of mulivarate analysis for the classification of large sample sets was also demonstrated showing high fidelity assignment of commercial formulations to their manufacturer. Five unburnt smokeless powders investigated using LEMS revealed unique combinations of organic molecules such as stabilizers and plasticizers using a simple electrospray solvent. Principal component analysis (PCA) provided exact classification of the mass spectra with respect to the manufacturer of the ordinance. LEMS measurements were then obtained from five commercial gunshot residue samples, or post-blast smokeless powder, revealing trace amounts of organics such as the stabilizers and large quantities of inorganic barium originating from the primer. Principal component analysis (PCA) again provided exact classification of the gunshot residue mass spectra with respect to the manufacturer of the ordinance. The use of a common transition metal complexation agent enabled full characterization of eight gunshot residue samples to include the heavy metals contained in the primer and the organics such as the stabilizers and plasticizers without any sample preparation or pre-concentration procedures. Principal component analysis (PCA) again provided high fidelity classification of the gunshot residue mass spectra with respect to the manufacturer of the ordinance after mass analysis with LEMS. Finally, highly energetic formulations such as composition 4 (C-4) and detonation cord subjected to nonresonant femtosecond laser vaporization enabled full characterization of these complex compositions identifying binders, stabilizers, the explosive ingredient and age-related decomposition derivative signature molecules with appreciable ion current detected using both positive and negative ion modes. / Chemistry