Advances in structure elucidation of small molecules using mass spectrometry

The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules

Acúmulo de nutrientes pela alface destinada à produção de sementes Nutrients uptake by lettuce plants for seed production

O objetivo deste trabalho foi determinar a curva de acúmulo de nutrientes pela planta de alface destinada à produção de sementes. O experimento foi conduzido na Fazenda Experimental São Manuel, pertencente à Faculdade de Ciências Agronômicas da Universidade Estadual Paulista, no período de 25/09/03 a 19/02/04. O delineamento experimental utilizado foi em blocos ao acaso com cinco repetições e seis tratamentos (épocas de coleta das plantas: 0, 20, 34, 49, 69 e 112 dias após o transplante (DAT)). Foi utilizada a alface crespa cultivar Verônica, sendo avaliados o acúmulo da massa seca e de N, P, K, Ca, Mg, S, B, Cu, Fe, Mn e Zn na parte aérea das plantas. O maior incremento da massa seca das plantas ocorreu após o ponto comercial (34 DAT). O período de maior demanda de macronutrientes foi entre o início do pendoamento e o início do florescimento. Observa-se que para a maioria dos micronutrientes o período de maior exigência foi após o início do florescimento. A ordem decrescente de acúmulo de nutrientes foi: K>N>Ca>Mg>P>S>Fe>Mn>Zn>B>Cu.<br>The nutrients uptake curve of lettuce plants for seed production was evaluated. The experiment was carried out from September 2003 to February 2004 at the Faculdade de Ciências Agronômicas of the Universidade Estadual Paulista, in Botucatu, São Paulo State, Brazil. A randomized block design was used, with five replicates and six treatments (periods of plant collection: 0, 20, 34, 49, 69 and 112 days after transplant (DAT)). We utilized the Verônica lettuce cultivar and evaluated the dry mass and the N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn accumulated in the aboveground part of the plants. The greatest increase in the plant dry matter occurred after the marketable point (34 DAT). The period of greatest demand for nutrients was between the beginning of the stem elongation stage and the beginning of the flowering stage. We also observed that for most micronutrients the period of highest demand was after the beginning of the flowering stage. Nutrients accumulation in descending order was: K>N>Ca>Mg>P>S>Fe>Mn>Zn>B>Cu

Obstinação terapêutica em Unidade de Terapia Intensiva: perspectiva de médicos e enfermeiros Obstinación terapéutica en Unidades de Cuidado Intensivo: perspectiva de médicos y enfermeros Therapeutic obstinacy at an Intensive Care Unit: perspective from doctors and nurses

O tema obstinação terapêutica ainda é insuficientemente estudado no Brasil, sobretudo pela enfermagem. Este estudo objetivou compreender as representações sociais de médicos e enfermeiros sobre o investimento excessivo no paciente terminal em Unidade de Terapia Intensiva Adulto. Trata-se de uma pesquisa qualitativa, exploratório-descritiva, fundamentada na Teoria das Representações Sociais. Os dados foram coletados por meio de entrevista focalizada e observação participante e interpretados pela análise de conteúdo. A seleção de cinco enfermeiros e oito médicos para concederem as entrevistas ocorreu por conveniência, a partir das escalas de serviço. Concluiu-se que estes profissionais constroem suas representações sociais sobre obstinação terapêutica partindo dos pedidos obstinados da família do paciente terminal para instituir medidas fúteis; das dificuldades de tomadas de decisão e da ausência de critérios quanto aos investimentos; e do receio das repercussões ético-legais em relação às decisões tomadas.<br>El tema obstinación terapéutica aún es insuficientemente estudiado en Brasil, principalmente en la enfermería. Este estudio objetivó comprender las representaciones sociales de médicos y enfermeros sobre la inversión excesiva en pacientes terminales en una Unidad de Terapia Intensiva Adulta. Se trata de una investigación cualitativa, exploratoria-descriptiva, fundamentada en la Teoría de las Representaciones Sociales. Los datos fueron colectados por medio de entrevistas focalizadas y observación participante, utilizando el Análisis de Contenido para su interpretación. La selección de los cinco enfermeros y ocho médicos para realizar las entrevistas se dio por conveniencia a partir de las escalas de servicio. Se concluye que estos profesionales, construyen sus representaciones sociales sobre la obstinación terapéutica partiendo de los pedidos obstinados del familiar del paciente terminal para instituir medidas fútiles; de las dificultades de tomar decisiones y de la ausencia de criterios que permitan saber hasta dónde invertir; como también del temor de repercusiones ético-legales en relación a estas decisiones.<br>Therapeutic obstinacy is not a sufficiently studied theme in Brazil, especially on the nursing field. This study aimed to understand the social representations of doctors and nurses, about the excessive investment regarding the terminal patient in an Adult Intensive Care Unit. It is a qualitative, exploratory and descriptive research, founded on Social Representations Theory. Data was collected through focused interviews and participant observation and was interpreted through content analysis. The selection of five nurses and eight doctors to give interviews was carried out for convenience, considering their working shifts. It is possible to conclude that such professionals build their social representations about therapeutic obstinacy, having as a starting point the obstinate requests of the terminal patient's family members to carry out futile measures; difficulties regarding decision making and absence of criteria concerning the limits of investment, as well as the fear of ethical and legal repercussions related to the decisions made

Two strings to the systems biology bow: co-extracting the metabolome and proteome of yeast

Experimental samples are valuable and can represent a significant investment in time and resources. It is highly desirable at times to obtain as much information as possible from a single sample. This is especially relevant for systems biology approaches in which several 'omics platforms are studied simultaneously. Unfortunately, each platform has a particular extraction methodology which increases sample number and sample volume requirements when multiple 'omics are analyzed. We evaluated the integration of a yeast extraction method; specifically we explored whether fractions from a single metabolite extraction could be apportioned to multiple downstream 'omics analytical platforms. In addition, we examined how variations to a chloroform/methanol yeast metabolite extraction regime influence metabolite recoveries. We show that protein suitable for proteomic analysis can be recovered from a metabolite extraction and that recovery of lipids, while reproducible, are not wholly quantitative. Higher quenching solution temperatures (-30 °C) can be used without significant leakage of intracellular metabolites when lower fermentation temperatures (20 °C) are employed. However, extended residence time in quenching solution, in combination with vigorous washing of quenched cell pellets, leads to extensive leakage of intracellular metabolites. Finally, there is minimal difference in metabolite amounts obtained when metabolite extractions are performed at 4 °C compared to extractions at -20 °C. The evaluated extraction method delivers material suitable for metabolomic and proteomic analyses from the same sample preparation