Evaluation of chemical kinetics in positive photoresists using laser desorption ionization

Martins, Jefferson S.; Borges, B. G. A. L.; Machado, Rafael Carvalhaes; Carpanez, Arthur G.; Grazul, Richard Michael; Zappa, Fábio; Melo, Wilson S.; Rocco, Maria Luiza M.; Pinho, R.R.; Lima, Carlos

doi:10.1016/j.eurpolymj.2014.07.005

Cited by 13 publications

(3 citation statements)

References 19 publications

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“…Second, this technique identified the m/z 304.24 peak related to the AA in both non-stimulated and AA-stimulated samples. In order to verify the existence of a fluctuation at the m/z 304.24 peak of the non-stimulated and AA-stimulated sample, the yield related to this peak was calculated by dividing the peak area by the total area of the corresponding spectrum, as before [ 48 ]. Thus, m/z 304.24 peak from the non-stimulated and AA-stimulated samples showed a related yield of 0.0035 and 0.018 respectively, that is, 5 times higher in the stimulated group ( Fig 5B , black line) compared to the value obtained from the non-stimulated sample ( Fig 5B , red line).…”

Section: Resultsmentioning

confidence: 99%

Lipid Body Organelles within the Parasite Trypanosoma cruzi: A Role for Intracellular Arachidonic Acid Metabolism

et al. 2016

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Most eukaryotic cells contain varying amounts of cytosolic lipidic inclusions termed lipid bodies (LBs) or lipid droplets (LDs). In mammalian cells, such as macrophages, these lipid-rich organelles are formed in response to host-pathogen interaction during infectious diseases and are sites for biosynthesis of arachidonic acid (AA)-derived inflammatory mediators (eicosanoids). Less clear are the functions of LBs in pathogenic lower eukaryotes. In this study, we demonstrated that LBs, visualized by light microscopy with different probes and transmission electron microscopy (TEM), are produced in trypomastigote forms of the parasite Trypanosoma cruzi, the causal agent of Chagas’ disease, after both host interaction and exogenous AA stimulation. Quantitative TEM revealed that LBs from amastigotes, the intracellular forms of the parasite, growing in vivo have increased size and electron-density compared to LBs from amastigotes living in vitro. AA-stimulated trypomastigotes released high amounts of prostaglandin E2 (PGE2) and showed PGE2 synthase expression. Raman spectroscopy demonstrated increased unsaturated lipid content and AA incorporation in stimulated parasites. Moreover, both Raman and MALDI mass spectroscopy revealed increased AA content in LBs purified from AA-stimulated parasites compared to LBs from unstimulated group. By using a specific technique for eicosanoid detection, we immunolocalized PGE2 within LBs from AA-stimulated trypomastigotes. Altogether, our findings demonstrate that LBs from the parasite Trypanosoma cruzi are not just lipid storage inclusions but dynamic organelles, able to respond to host interaction and inflammatory events and involved in the AA metabolism. Acting as sources of PGE2, a potent immunomodulatory lipid mediator that inhibits many aspects of innate and adaptive immunity, newly-formed parasite LBs may be implicated with the pathogen survival in its host.

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Section: Resultsmentioning

confidence: 99%

Lipid Body Organelles within the Parasite Trypanosoma cruzi: A Role for Intracellular Arachidonic Acid Metabolism

et al. 2016

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“…The time-of-flight mass spectrometer consists basically of an electrostatic ion extraction system, a collimating electrostatic lens, a drift tube, an electrostatic mirror and a pair of microchannel plate (MCP) detectors, disposed in the chevron configuration (refletron detector) [20]. After extraction, ionic molecular fragments travel through the flight tube until reaching the MCP.…”

Section: Methodsmentioning

confidence: 99%

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

et al. 2016

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Schistosomiasis is a neglected tropical disease of a significant public health impact. The water rat Nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in Brazil, being considered a wild reservoir. Cellular mechanisms that contribute to the physiological adaptation of this rodent to the Schistosoma mansoni parasite are poorly understood. Here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessive lipid accumulation with formation of lipid droplets (LDs) within hepatocytes, occurs in response to the natural S. mansoni infection of N. squamipes, captured in an endemic region. Significant increases of LD area in the hepatic tissue and LD numbers/hepatocyte, detected by quantitative histopathological and ultrastructural analyses, were paralleled by increased serum profile (total cholesterol and triglycerides) in infected compared to uninfected animals. Raman spectroscopy showed high content of polyunsaturated fatty acids (PUFAs) in the liver of both groups. MALDI-TOFF mass spectroscopy revealed an amplified pool of omega-6 PUFA arachidonic acid in the liver of infected animals. Assessment of liver functional activity by the levels of hepatic transaminases (ALT and AST) did not detect any alteration during the natural infection. In summary, this work demonstrates that the natural infection of the wild reservoir N. squamipes with S. mansoni elicits hepatic steatosis in the absence of liver functional harm and that accumulation of lipids, markedly PUFAs, coexists with low occurrence of inflammatory granulomatous processes, suggesting that lipid stores may be acting as a protective mechanism for dealing with the infection.

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“…Matrix-assisted laser desorption/ionization timeof-flight mass spectrometry (MALDI-TOF MS) [1,2] has, as main characteristics, the easy sample production, soft ionization, easy operation, fast analysis and high accuracy. Mass spectrometry MALDI has been widely used in analyses of large molecules such as proteins [3], peptides [4], polysaccharides [5], oligonucleotides [6], Polymer [7,8], and DNA [9].…”

Section: Introductionmentioning

confidence: 99%

A A new matrix of MALDI-TOF MS derivative of 9-aminoacridine for lipid identification in positive ions mode

Martins

Zappa

Silva

et al. 2020

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Matrix-assisted laser desorption/ionization (MALDI) has evolved to become a well- established technique during the last decades. Because of matrix peak interference in the low molecular-weight region, however, new matrices are often studied with the purpose of improving the spectral quality under m/z 500. Herein, we present the substance 2,4,5,7-tetranitro-9-aminoacridine (TNA) as a suitable alternative matrix for lipid detection in the positive-ion mode. TNA is obtained from 9-aminoacridine, a matrix commonly used to analyze lipids in negative-ion mode, with the addition of 4 nitro groups through a synthetic path. The procedure results in a highly conjugated system that presents a bigger electronic dispersion and therefore higher UV absorption. First, we demonstrated the high sensitivity of TNA for retinol. Second, TNA was applied to detect lipids in the liver of the water rat Nectomys squamipes. By using this natural model of hepatic steatosis (fat liver), a condition in which there is excessive accumulation of lipids, TNA provided a clearer identification of three species of polyunsaturated fatty acids (PUFAs) compared to other matrices. TNA presents better sensitivity and spectral resolution, little or no interference from matrix ions, high intensity of signal and low cost with high yield of matrix production.

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Evaluation of chemical kinetics in positive photoresists using laser desorption ionization

Cited by 13 publications

References 19 publications

Lipid Body Organelles within the Parasite Trypanosoma cruzi: A Role for Intracellular Arachidonic Acid Metabolism

Lipid Body Organelles within the Parasite Trypanosoma cruzi: A Role for Intracellular Arachidonic Acid Metabolism

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

A A new matrix of MALDI-TOF MS derivative of 9-aminoacridine for lipid identification in positive ions mode

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