Determinação do nitrogênio da biomassa microbiana do solo (BMS-N).

Materiais e equipamentos necessários; Para fumigação; Para extração; Para determinação do nitrogênio microbiano; Amsotra; Limitações do método; Procedimento; Preparação da amostra; Determinação da umidade na capacidade de campo do solo; Procedimento analítico; Determinação da umidade do solo; Fumigação; Extração; Determinação do nitrogênio microbiano; Cálculo da molaridade exata da solução de ácido sulfúrico (H2S04) 0,015M; Cálculo do teor de N nos extratos (Equação 4); Cálculo da BMS-N; Equação 5.bitstream/CNPAB-2010/34388/1/cot096.pdfParceria: UFRR

Scanning Electron Microscope Cytochemistry of Blood Cells

The backscattered electron imaging (BEI) mode of scanning electron microscopy (SEM) has been applied to study various histo-cytochemical reactions in biological specimens since the early seventies. Due to numerous, recent technical improvements the BEI mode of SEM now belongs to the routine of many SEM laboratories. For cytochemistry, BEI has been mainly used to: visualize intracellular structures and organelles; recognize the different cell types in heterogeneous populations or tissues; study the correlations between enzymatic activities and cell surface features. We have evaluated the most relevant results obtained in the study of blood cells and the possible future applications of these techniques

Microbial soil quality indicators under different crop rotations and tillage management.

An experiment was carried out under field conditions to assess the effects of soil management (no-tillage- NT and conventional tillage- CT) and crop rotation systems on microbial biomass-C (Cmic), basal soil respiration (BSR), metabolic quotient (qCO2), soil organic carbon content (Corg) and microbial carbon to organic carbon ratio (Cmic/Corg). Soil samples were collected on an area cultivated with wheat as winter crop and soybean as summer crop, both in rotation with vetch, maize and oats. Samples were also collected in a secondary forest used as reference. Data of each management system (NT and CT) were compared to forest area by ?t? test (p<0.05) and crop rotations were compared by Tukey test (p<0.05). All data were submitted to multivariate analysis (Principal Component Analysis - PCA). There were observed significant differences (?t? test; p<0.05) for Cmic, BSR, qCO2 and Cmic/Corg between NT and CT, by which NT values resemble those for forest area. For crop rotations significant differences (Tukey test; p<0.05) were found only for BSR and qCO2. The sum of the two first principal components on the PCA explained about 75% of the data variation. PCA showed NT closest to forest area than CT, especially treatments with soybean and vetch as consecutive crops. The forest area-NT clustering was mostly due to Cmic and Cmic/Corg relationship. Results indicate that the NT system is more sustainable than the CT system and can contribute for the accumulation a greater quantity of carbon in soil

Fertilizantes de leguminosas como fontes alternativas de nitrogênio para produção orgânica de alface.

O objetivo deste trabalho foi avaliar o potencial de dois fertilizantes de leguminosas - produtos derivados do corte, desidratação e moagem da biomassa aérea das leguminosas mucuna-cinza (Mucuna pruriens) e gliricídia (Gliricidia sepium) - como fontes alternativas de nitrogênio (N) para a produção orgânica de alface (Lactuca sativa cv. Vera), e a influência dessas adubações sobre a vida útil pós-colheita da hortaliça, em condições de laboratório. Esses fertilizantes foram empregados em cobertura e comparados com cama-de-aviário industrial, assegurando-se doses equivalentes de N total. O delineamento experimental foi o de blocos ao acaso, com cinco tratamentos e quatro repetições: T1: adubação pré-plantio, com termofosfato sílico-magnesiano + sulfato de potássio; T2: T1 + esterco bovino, em pré-plantio; T3: T2 + fertilizante de mucuna-cinza, em cobertura; T4: T2 + fertilizante de gliricídia, em cobertura; T5: T2 + cama-de-aviário em cobertura. Não houve diferença entre os fertilizantes de ambas as espécies de leguminosas e a cama-de-aviário, quanto à produtividade, teor de N, padrão comercial e período de vida útil pós-colheita das alfaces, o que indica potencial de uso desses fertilizantes como fontes de N para sistemas orgânicos de produção de hortaliças. The objective of this work was to evaluate the potential use of two legume fertilizers - products derived from cutting, dehydration and milling of the aerial biomass of legume plants, velvet bean (Mucuna pruriens) and gliricidia (Gliricidia sepium) - as alternative sources of N for organic production of lettuce (Lactuca sativa cv. Vera); and to evaluate the influence of soil fertilization on lettuce shelf life at laboratory bench condition. These fertilizers were applied on soil surface and compared to factory poultry-bed manure at equivalent total N doses. The experimental design consisted of randomized blocks with five treatments and four replications, as following: T1: pre-planting fertilization with magnesium thermophosphate + potassium sulphate; T2: T1 + cattle manure in pre-planting; T3: T2 + velvet bean fertilizer in covering; T4: T2 + gliricidia fertilizer in covering; and T5: T2 + poultry-bed manure in covering. Fertilizers of both legume species were not statistically different of poultry-bed manure, regarding productivity, N content, commercial standard and shelf life of lettuce, which indicates promising potential for their use in organic horticultural production systems.Parceria: UFRRJ

Espectroscopia infravermelha para a determinação de carbono do solo: perspectiva de um método economicamente viável e ambientalmente seguro.

O objetivo deste trabalho foi apresentar a utilidade das técnicas DRIFTS e NIRS na determinação quantitativa de carbono total (CT) determinado por combustão via seca e carbono orgânico (CORG) determinado por oxidação com dicromato de potássio, usando uma série heterogênea e representativa de solos do Brasil. Calibrações foram feitas para o número total das amostras e para as sub-populações de amostras com base no teor de C, classe de solo e grupo textural.bitstream/CNPAF/25440/1/comt_126.pd

Estudo de variáveis de solo, vegetação e condicionamento de amostras de solo sobre a biomassa microbiana do solo no Estado do Rio de Janeiro.

Umidade da amostra. Pré-condicionamento da amostra. A influência da profundidade e tipo de cobertura. Tipos de solos.bitstream/CNPAB-2010/27315/1/doc090.pd

Lipid accumulation in human breast cancer cells injured by iron depletors

Background: Current insights into the effects of iron deficiency in tumour cells are not commensurate with the importance of iron in cell metabolism. Studies have predominantly focused on the effects of oxygen or glucose scarcity in tumour cells, while attributing insufficient emphasis to the inadequate supply of iron in hypoxic regions. Cellular responses to iron deficiency and hypoxia are interlinked and may strongly affect tumour metabolism. Methods: We examined the morphological, proteomic, and metabolic effects induced by two iron chelators-deferoxamine (DFO) and di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT)-on MDA-MB-231 and MDA-MB-157 breast cancer cells. Results: These chelators induced a cytoplasmic massive vacuolation and accumulation of lipid droplets (LDs), eventually followed by implosive, non-autophagic, and non-apoptotic death similar to methuosis. Vacuoles and LDs are generated by expansion of the endoplasmic reticulum (ER) based on extracellular fluid import, which includes unsaturated fatty acids that accumulate in LDs. Typical physiological phenomena associated with hypoxia are observed, such as inhibition of translation, mitochondrial dysfunction, and metabolic remodelling. These survival-oriented changes are associated with a greater expression of epithelial/mesenchymal transcription markers. Conclusions: Iron starvation induces a hypoxia-like program able to scavenge nutrients from the extracellular environment, and cells assume a hypertrophic phenotype. Such survival strategy is accompanied by the ER-dependent massive cytoplasmic vacuolization, mitochondrial dysfunctions, and LD accumulation and then evolves into cell death. LDs containing a greater proportion of unsaturated lipids are released as a consequence of cell death. The consequence of the disruption of iron metabolism in tumour tissue and the effects of LDs on intercellular communication, cancer-inflammation axis, and immunity remain to be explored. Considering the potential benefits, these are crucial subjects for future mechanistic and clinical studies

Quasi-elastic and inelastic inclusive electron scattering from an oxygen jet target

The results of an experiment on inclusive electron scattering from an oxygen jet target, performed in a wide range of energy and momentum transfer covering both quasi-elastic and $\Delta$(1232) resonance regions, are reported. In the former region the theoretical predictions, obtained including effects of nucleon-nucleon correlations in both initial and final states, give a good description of the experimental data. In the inelastic region a broadening as well as a damping of the resonant part of the cross section with respect to the free nucleon case is observed. The need of more detailed calculations including nuclear structure effects on the electroproduction cross section of nucleon resonances is highlighted.Comment: to appear in Nucl. Phys.

A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR

Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-C-13(2)-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (similar to 120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40A degrees, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed

Aspectos moleculares da transmissão sináptica

O Sistema Nervoso Central produz o nosso estado consciente mediante um contínuo fluxo de informações e armazenamento de memórias ao longo da vida, a partir de diferentes estímulos externos. Ao mesmo tempo, controla a concentração dos nossos fluidos internos e o trabalho de músculos e glândulas. A transmissão sináptica é o processo básico de toda esta atividade. Bilhões de neurônios se comunicam entre si via milhares de sinapses, e cada sinapse, por sua vez, é uma estrutura regulada independentemente. A partir desta complexidade, em lugar de caos, surge uma singular ordem na informação processada pelo cérebro. A secreção de neurotransmissores na zona ativa da sinapse é o evento primário da comunicação interneuronal. Este processo é regulado por um tráfego de membranas altamente orquestrado dentro do terminal présináptico. Os neurotransmissores são armazenados em vesículas sinápticas. A despolarização de um terminal nervoso por um potencial de ação resulta na abertura de canais de cálcio, operados por voltagem. O influxo de Ca resultante deflagra a exocitose, que é uma rápida fusão de vesículas com a membrana plasmática, liberando neurotransmissores para a fenda sináptica. A exocitose envolve a junção de proteínas intrínsecas das membranas plasmáticas, vesicular e pré-sináptica, mediante proteínas específicas de ancoragem e fusão na zona ativa (SNARE). Em seguida à liberação, as membranas das vesículas são rapidamente reincorporadas via endocitose e recicladas dentro do terminal sináptico. O terminal é, portanto, uma unidade autônoma que contém todos os elementos requeridos para a exocitose das vesículas, as proteínas responsáveis pela biossíntese do neurotransmissor e recaptação das vesículas. Uma vez liberado, o neurotransmissor difunde através da fenda sináptica e interage com proteínas receptoras na membrana do neurônio póssináptico produzindo, em uma fração de milissegundo, uma permeabilidade intensa e temporária aos íons Na + e K+, provocando a despolarização total de cerca de 100 mV desde um potencial de repouso em torno de -60mV. Isto gera um potencial de ação que se difunde ao longo da membrana do neurônio pós-sináptico, podendo alcançar o seu próprio&nbsp; erminal e deflagrar novo movimento de Ca 2+&nbsp;para o citosol, gerando um novo potencial. Várias proteínas dentro do terminal pós-sináptico estão envolvidas neste processo. É geralmente aceito que os processos de aprendizado e memória resultam de mudanças estruturais e bioquímicas em sinapses específicas que alteram a liberação de neurotransmissores e a ação pós-sináptica. Tais alterações podem ser registradas eletrofisiologicamente como uma potenciação ou depressão de duração longa (LTP ou LTD) ou a combinação de ambas.&nbsp;The Central Nervous System produces our conscious state out of various externa inputs in a continuous stream of information and storing a lifetime of memories, while keeping track of the concentration of our internal fluids and the work of muscles and glands. Synaptic transmission is the key process of all that activity. Billions of neurons communicate with each other via thousands of synapses, each of which is independently regulated. From that complexity, instead of chaos, arises the pristine order of information processed by the brain. The secretion of neurotransmitters at the synaptic active zone is the primary event of interneuronal communication. This process is regulated by a highly orchestrated cycle of membrane trafficking within the presynaptic nerve terminal. Neurotransmitters are stored in synaptic vesicles. Depolarization of the nerve terminal by an action potential results in the opening of voltage-gated Ca 2+ channels. The resulting influx of calcium ions triggers exocytosis which is a rapid fusion of the vesicles with the plasma membrane, releasing neurotransmitters into the synaptic cleft. Exocytosis involves the linking of intrinsic membrane proteins of the vesicle and the plasma membranes by specific docking and fusion, the SNARE proteins, at the active zone. The vesicle membranes are rapidly retrieved by endocytosis and the synaptic vesicles recycled within the nerve terminal. The nerve terminal is thus an autonomous unit that contains all elements required for synaptic vesicle exocytosis and proteins responsible for neurotransmitter biosynthesis and vesicular uptake. Once the neurotransmitter have been released, diffuses across the synaptic cleft and combines with receptor molecules in the membrane of the postsynaptic neuron producing, in a fraction millisecond, a large transient increased permeability to Na&nbsp;+ and K+ ions, provoking a net depolarization to about 100mV from the resting potential of about&nbsp;-60mV. This generates an action potential which spreads along the surface of the postsynaptic cell membrane which in turn may trigger Ca&nbsp;2+&nbsp;movement to the cytosol in the synaptic terminal to generate a new response. Several proteins inside the post synaptic terminal are involved in this process. It is generally accepted that learning and memory result from structural and biochemical changes in specific synapses which alter neurotransmitter release and post synaptic action. These alterations are perceivable electrophysiologically as a long term potentiation (LTP),long term depression (LTD), or a combination of both.&nbsp