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Isolamento e caracterização de microrganismo envolvido na desnitrificação autrófica pela oxidação de sulfeto em reator vertical de leito fixo; Isolation and characterization of a microorganism involved on autotrophic denitrification by sulfide oxidation in a vertical fixed-bed reactor

Mestrinelli, Fabiana
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 15/10/2010 PT
Relevância na Pesquisa
26.69%
O presente estudo teve como objetivo avaliar a comunidade envolvida na desnitrificação autotrófica pela oxidação de sulfetos, aplicada ao pós-tratamento de efluentes anaeróbios. O enriquecimento da comunidade bacteriana e da comunidade desnitrificante autotrófica foi realizado a partir de amostras da biomassa coletadas de três reatores verticais de leito fixo operados em condições distintas, sendo, redução autotrófica de nitrato, redução autotrófica de nitrito e redução autotrófica de nitrato com excesso de sulfeto. Após a determinação da melhor condição de enriquecimento, a cultura foi purificada, identificada por meio de ferramentas da biologia molecular e caracterizada quanto às melhores condições de crescimento. O enriquecimento foi bem sucedido com a biomassa dos três reatores. No entanto, a condição de redução de nitrato com relação 'N'/'S' igual a 0,8 foi a que apresentou maior concentração de microrganismos desnitrificantes autotróficos. A bactéria isolada foi identificada como Pseudomonas stutzeri. A velocidade específica máxima de crescimento da cultura ('mü'máx) foi de 0,037/h, com tempo de duplicação de 18,7 horas. O rendimento celular (Y) do composto nitrogenado foi de 0,15 gSSV.g/'N' e a velocidade de desnitrificação foi de aproximadamente 0...

Avaliação da influência da etapa de salga do abate Shechita na população de Salmonella sp e de micro-organismos indicadores em carcaças de frango; Evaluation of the influence of salting step of Shechita slaughter in the detection of Salmonella sp and indicator microorganism in chicken carcasses.

Tavares, Maria Fernanda Paiva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/06/2013 PT
Relevância na Pesquisa
26.69%
Um importante micro-organismo causador de doenças de origem alimentar, presente em animais e no homem, é a Salmonella spp. Sua presença no intestino, na pele e entre as penas das aves pode levar à contaminação das carcaças no momento do abate. Pode ocorrer também a contaminação do próprio ambiente de abate, dos manipuladores além da contaminação cruzada entre os animais. Apesar de o Brasil ser um grande produtor de aves, pouco se sabe sobre a influência de abates realizados sob preceitos religiosos na qualidade microbiológica das carcaças produzidas. Dentre os abates religiosos está o abate Schechita que se diferencia do abate convencional pela não realização da escalda antes da depenagem das aves, bem como a utilização do melichah - que tem como uma de suas etapas a aplicação a seco de cloreto de sódio nas carcaças, seguida de sua lavagem. O presente estudo tem por objetivo avaliar a influência do melichah sobre a ocorrência de Salmonella e sobre a população de enterobactérias em carcaças de frangos. Para tanto, foram avaliadas 318 carcaças de aves, sendo 159 obtidas antes da etapa de salga e 159 após a dessalga, coletadas em um abatedouro sob fiscalização do Serviço de Inspeção Federal do MAPA. As carcaças foram submetidas ao enxágue com solução salina e o caldo resultante transportado ao laboratório da FCF-USP para análise. Também se determinou o peso das carcaças; aferiu-se a temperatura das mesmas e o teor de cloro livre na água do tanque de dessalga. A detecção da presença de Salmonella spp. foi realizada conforme a metodologia ISO 6579:2002...

Produtos naturais marinhos: identificação de metabólitos fenólicos halogenados na macroalga Bostrychia tenella (Rhodomelaceae, Rhodophyta) e potencial biológico de micro-organismos endofíticos associados; Marine natural products: halophenolic metabolites identification in the seaweed Bostrychia tenella (Rhodomelaceae, Rhodophyta) and biological potential of associated endophytic microorganisms

Felício, Rafael de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 07/10/2010 PT
Relevância na Pesquisa
26.82%
O ambiente marinho desponta como uma fonte natural importante devido à sua fantástica diversidade orgânica, que permanece praticamente inexplorada. Abordagens químicas e biológicas de organismos marinhos, atualmente, representam uma área de pesquisa ampla e promissora, visto a constante descoberta de diversos metabólitos com propriedades medicinais variadas, além de um arsenal metabólico praticamente ilimitado. Algas vermelhas, com destaque para a família Rhodomelaceae, são exímias produtoras de metabólitos halogenados aos quais são atribuídos importantes atividades biológicas. Micro-organismos marinhos e/ou endofíticos são apontados como os alvos mais promissores para descoberta de novos fármacos. Neste contexto, o presente trabalho descreve a identificação de metabólitos secundários da macroalga Bostrychia tenella (Rhodomelaceae, Rhodophyta), a qual possui poucos relatos na literatura a respeito de seu metabolismo secundário, bem como o potencial biológico de micro-organismos endofíticos associados a esta espécie. O estudo químico da espécie B. tenella coletada nos costões rochosos da Praia da Fortaleza (Ubatuba-SP) proporcionou a identificação, por meio de análises via CG-EM (fração acetato), de 63 metabólitos dos quais 39 são substâncias apolares de cadeias carbônicas longas (ex. ácidos graxos e ésteres...

Optimisation of High Hydrostatic Pressure Processing of Pêra Rio Orange Juice

Bisconsin-Junior, Antonio; Rosenthal, Amauri; Monteiro, Magali
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 1-8
ENG
Relevância na Pesquisa
26.69%
The influence of high hydrostatic pressure (HHP) on Pêra Rio orange juice was investigated using response surface methodology. A central composite design was used to evaluate the effects of three processing conditions (independent variables), namely pressure (100-600 MPa), temperature (30-60 °C) and time (30-360 s), on the native microflora and pectin methylesterase (PME) activity of orange juice. Analysis of variance showed that second-order polynomial models fitted well with the experimental data for PME residual activity (R2 = 0.9586, p < 0.001) and aerobic microorganism count (R2 = 0.9879, p < 0.001). The optimum HHP processing conditions to produce orange juice with PME residual activity of less than 20 % and low microorganism count (<2 log cycles CFU/mL) were 550 to 600 MPa, 55 to 60 °C and 330 to 360 s. © 2013 Springer Science+Business Media New York.

Resíduos agroindustriais como potenciais substratos para a produção de renina microbiana por Mucor miehei utilizando fermentação em estado sólido

Silveira, Guilherme Garcia da
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: vii, 101 f. : il., gráfs., tabs.
POR
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Pós-graduação em Ciências Biológicas (Microbiologia Aplicada) - IBRC; Neste trabalho foi estudada a produção de renina microbiana pelo zigomiceto Mucor miehei utilizando Fermentação em Estado Sólido (FES). Os substratos utilizados foram farelos de trigo, laranja, aveia e arroz, bagaço de cana e casca de café. Foi estudada também a combinação de várias quantidades de dois substratos diferentes já mencionados. Dos substratos utilizados, não houve crescimento evidenciado do fungo quando foi utilizado, casca de café, bagaço de cana e farelo de laranja. Caseína é um importante fator na potencialização da biosíntese de renina tanto em fermentação submersa quanto em Fermentação em Estado Sólido. Nos experimentos com farelos de trigo e aveia as maiores atividades enzimáticas foram observadas entre 48 e 72 horas de cultivo, umidade acima de 79% e o aumento da quantidade de farelo de trigo na mistura foi favorável no que diz respeito ao aumento desta atividade. Nos experimentos com farelos de trigo e arroz sem suplementação de caseína, todas as combinações de meio de cultivo foram estatisticamente significativas sobre a atividade enzimática. Umidades acima de 98 % parecem inibir o crescimento do fungo e...

Troubleshooting of filamentous bulking using biofilm reactors

Matos, M.; Pereira, M. A.; Nicolau, Ana; Rodrigues, A. L.; Brito, A. G.; Nogueira, R.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2010 ENG
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The present work aims to evaluate filamentous bulking control in systems combining suspended biomass with biofilm growth. For this study, four sequencing batch reactors (SBR)fed with an easy biodegradable substrate (acetate) were operated without (SBR1) and with support for biofilm growth [5 % (SBR2), 10 % (SBR3) and 20 % (SBR4) of the reactor volume]. The results demonstrated an overabundance of a filamentous fungi-like microorganism in the SBR operating just with suspended biomass. The incorporation of an optimized amount of support for biofilm growth (10 % and 20 %) seemed to suppress the overgrowth of this filamentous microorganism probably due to the combined effect of a decreased biomass loading rate and the physical cut or breakdown of filaments induced by particle-to-particle collisions. Besides the observed differences in terms of the filamentous fungi-like microorganism, the incorporation of a support material for biofilm growth was also found to induce increasing differences in the bacterial community structure as the concentration of support increased in the SBR.

Styrofoam Cup-Membrane Assembly for Studying Microorganism-Root Interactions

Hartel, Peter G.; Billingsley, Jean W.; Williamson, Joseph W.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1989 EN
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An assembly consisting of Styrofoam cups with membranes of varying porosities was developed to study microorganism-root interactions. The assembly permitted uniform distribution of a bacterium in soil and was simple, easy to use, and disposable. In tests with the bacterium Pseudomonas solanacearum, little difference in P. solanacearum survival was observed in the rhizosphere or nonrhizosphere of tomato.

Dissimilatory Fe(III) Reduction by the Marine Microorganism Desulfuromonas acetoxidans

Roden, Eric E.; Lovley, Derek R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1993 EN
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26.69%
The ability of the marine microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c-type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)-citrate and Mn(IV)-oxalate, as well as by two electron acceptors known to support growth, colloidal sulfur and malate. D. acetoxidans grew in defined anoxic, bicarbonate-buffered medium with acetate as the sole electron donor and poorly crystalline Fe(III) or Mn(IV) as the sole electron acceptor. Magnetite (Fe3O4) and siderite (FeCO3) were the major end products of Fe(III) reduction, whereas rhodochrosite (MnCO3) was the end product of Mn(IV) reduction. Ethanol, propanol, pyruvate, and butanol also served as electron donors for Fe(III) reduction. In contrast to D. acetoxidans, G. metallireducens could only grow in freshwater medium and it did not conserve energy to support growth from colloidal S0 reduction. D. acetoxidans is the first marine microorganism shown to conserve energy to support growth by coupling the complete oxidation of organic compounds to the reduction of Fe(III) or Mn(IV). Thus...

Properties of α-Aminoisobutyric Acid Transport in a Thermophilic Microorganism

Reizer, Jonathan; Grossowicz, Nathan
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1974 EN
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Uptake of α-aminoisobutyric acid (AIB) by a leucine-tyrosine auxotroph of a thermophilic microorganism starved for leucine was studied. AIB was taken up by the cells against a substantial concentration gradient (300:1) and was present there in a free and unchanged form. Various energy inhibitors and sulfhydryl reagents strongly inhibited the accumulation of AIB. AIB uptake obeyed saturation kinetics, and the Lineweaver-Burk plot is characterized by a biphasic curve. AIB most probably shares a common transport system(s) with alanine, serine, and glycine. A mutant defective in l-alanine uptake was isolated by using the suicide effect due to accumulation of the tritiated substrate. The mutant also exhibited impaired transport activity towards AIB, glycine, and l-serine, but not to phenylalanine or valine. The transport of AIB, glycine, l-alanine, and l-serine was induced by d-alanine (5 × 10−3 M) during growth in a succinate- and ammonia-containing medium. De novo protein synthesis was required for the induction of AIB transport; the induction was inhibited when growth occurred in glucose-containing media. The apparent differential rate of synthesis of the AIB transport system was decreased considerably in glucose-grown cells as compared to succinate-grown cells. A common genetic basis of either the regulatory or structural nature for the transport of AIB...

Production of choriogonadotropin-like factor by a microorganism.

Maruo, T; Cohen, H; Segal, S J; Koide, S S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1979 EN
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Extracts from an acetone powder preparation of a culture of a microorganism tentatively named Progenitor cryptocides contain choriogonadotropin (CG)-like factor as determined by radioimmunoassay with antiserum to human (h)CG beta subunit COOH-terminal peptide and radioreceptor assay with bovine corpus luteum membranes. Possible interference by proteases in the extracts was excluded. Immunoreactive materials reacting with antisera to hCG beta subunit and hCG beta subunit COOH-terminal peptide were also found in the extracts. No free alpha subunit was detected. The CG-like factor was purified by chromatography on Sephadex G-100, concanavalin A-Sepharose, and DEAE-Sephadex A-50. The factor was adsorbed by concanavalin A-Sepharose, suggesting that it contains mannose and glucose moieties. The factor was eluted at the same position as standard hCG on Sephadex G-100. It dissociated into two bands when subjected to sodium dodecyl sulfate/polyacrylamide gel electrophoresis; the bands corresponded to the respective standard hCG subunits. The biological activity of the purified factor as determined by the rat uterine weight assay and the ovarian weight assay was equivalent to 380 (95% confidence limits: 320-490) and 880 (780-1020) international units/mg...

Extraction and partial characterization of a leukotoxin from a plaque-derived Gram-negative microorganism.

Tsai, C C; McArthur, W P; Baehni, P C; Hammond, B F; Taichman, N S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1979 EN
Relevância na Pesquisa
26.82%
The plaque-derived gram-negative microorganism Y4 identified as a member of the genus Actinobacillus, was tested for a soluble cytotoxic factor(s). Sonication or incubation of viable Y4 microorganisms in distilled water or normal human serum resulted in liberation of a soluble material which was cytotoxic in vitro for human polymorphonuclear leukocytes (PMNs). The Y4 soluble sonic extract was also cytotoxic to human peripheral blood monocytes. However, human lymphocytes, platelets, and fibroblasts, as well as rabbit, rat, and mouse leukocytes and chicken embryo fibroblasts, were not killed by exposure to the Y4 sonic extract. No hemolytic activity was detected in the Y4 sonic extract. No hemolytic activity was detected in the Y4 sonic extract. Consequently, the factor(s) in the Y4 sonic extract was referred to as Y4 leukotoxin. The Y4 leukotoxin was inactive at 4 degrees C, heat sensitive (56 degrees C, 30 min), and inactivated by proteases. The cytotoxic effect of Y4 leukotoxin on PMNs was dose, time, and temperature dependent. The leukotoxin did not bind to viable PMNs at 4 degrees C but did bind to dead PMN membrane components at both 4 and 37 degrees C. The addition of bovine serum albumin (51 mg/ml) to PMN-Y4 leukotoxin cultures inhibited the release of lactate dehydrogenase from the PMNs...

CONCERNING SURVIVAL AND VIRULENCE OF THE MICROORGANISM CULTIVATED FROM POLIOMYELITIC TISSUES

Flexner, Simon; Noguchi, Hideyo; Amoss, Harold L.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 01/01/1915 EN
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26.97%
The minute microörganism cultivated from poliomyelitic tissues survives and maintains its pathogenicity in cultures for more than one year. Upon inoculation into monkeys poliomyelitis may fail to appear upon the first injection and yet follow from the effects of successive injections of the culture. Inoculations of cultures into monkeys which fail to produce paralysis may fail also to induce resistance or immunity. In this respect the action of the cultures resembles that of the virus as contained in infected nervous tissues. The lesions occurring in the spinal cord, medulla, and intervertebral ganglia of the monkeys which respond to the several inoculations of the cultures are identical with those present in the nervous organs of the animals responding to injection of the ordinary virus. Glycerinated nervous tissues derived from the monkeys responding to several injections of the cultures transmit experimental poliomyelitis to monkeys upon intracerebral inoculation. The microörganism inoculated may be recovered in cultures from the monkeys which develop poliomyelitis; but cultivation from the brain tissue is attended with the usual difficulties surrounding the obtaining of the initial growth. The microörganism cultivated from poliomyelitic tissues is adapted with difficulty to saprophytic conditions of multiplication...

A FILTERABLE YEAST-LIKE MICROORGANISM (SCHIZOSACCHAROMYCES FILTRANS, N. SP.)

Lewis, Paul A.
Fonte: The Rockefeller University Press Publicador: The Rockefeller University Press
Tipo: Artigo de Revista Científica
Publicado em 31/01/1927 EN
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A microorganism cultivated in the course of experiments with the virus of hog cholera shows the following points of interest. It is pleomorphic in extreme degree. Among the forms are coccoid and bacillary bodies at the lower limits of visibility. The culture can be completely regenerated after filtration through some Berkefeld N filters although these retain Bacillus abortus (Bang). The culture is carried forward by multiplication of forms of easy visibility (1.5µ). Associated with these at times are still larger forms bearing a striking general resemblance to those yeasts which develop abortive mycelia. Motile bacillary forms appear to arise as buds or branches from round or ovoid cocci. While cognizance is taken of possible alternatives the microorganism is provisionally classified with the yeasts and recognizing its filterability is named Schizosaccharomyces filtrans. The culture is not pathogenic for swine.

Three-dimensional two-component velocity measurement of the flow field induced by the Vorticella picta microorganism using a confocal microparticle image velocimetry technique

Nagai, Moeto; Oishi, Masamichi; Oshima, Marie; Asai, Hiroshi; Fujita, Hiroyuki
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
Publicado em 26/03/2009 EN
Relevância na Pesquisa
26.82%
Understanding the biological feeding strategy and characteristics of a microorganism as an actuator requires the detailed and quantitative measurement of flow velocity and flow rate induced by the microorganism. Although some velocimetry methods have been applied to examine the flow, the measured dimensions were limited to at most two-dimensional two-component measurements. Here we have developed a method to measure three-dimensional two-component flow velocity fields generated by the microorganism Vorticella picta using a piezoscanner and a confocal microscope. We obtained the two-component velocities of the flow field in a two-dimensional plane denoted as the XY plane, with an observation area of 455×341 μm2 and the resolution of 9.09 μm per each velocity vector by a confocal microparticle image velocimetry technique. The measurement of the flow field at each height took 37.5 ms, and it was repeated in 16 planes with a 2.50 μm separation in the Z direction. We reconstructed the three-dimensional two-component flow velocity field. From the reconstructed data, the flow velocity field [u(x,y,z),v(x,y,z)] in an arbitrary plane can be visualized. The flow rates through YZ and ZX planes were also calculated. During feeding, we examined a suction flow to the mouth of the Vorticella picta and measured it to be to 300 pl∕s.

Pyogenic vertebral osteomyelitis: identification of microorganism and laboratory markers used to predict clinical outcome

Yoon, Sang Hoon; Chung, Sang Ki; Kim, Ki-Jeong; Kim, Hyun-Jib; Jin, Yong Jun; Kim, Hong Bin
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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26.82%
The aim of this study is to determine the predictive values of laboratory indicators of pyogenic vertebral osteomyelitis (PVO) and a potential cure if the microorganism cannot be identified. Forty-five consecutive patients with PVO were enrolled. Antibiotic therapy with or without surgery was performed according to microorganism. In the negative-culture (NC) group, cefazolin was administered in cases of hematogenous PVO, and vancomycin was administered in cases of postoperative or procedure-related PVO. The clinical, laboratory, and radiological findings were followed up with regard to an appropriate response to antimicrobial therapy. Nine patients were treated with antibiotics alone. We were able to identify the microorganism in 34 cases (75.6%). Ten cases in NC group were cured without recurrence, but one was not. Identification of the microorganisms did not have any significant influence on the treatment outcome, duration of antibiotic administration or normalization of laboratory profiles. For erythrocyte sedimentation rate (ESR) values over 55 mm/h and C-reactive protein (CRP) values of 2.75 mg/dL at fourth week after antibiotic administration by means of ROC curve analysis, we expect significantly high rates of treatment failure by Pearson χ2 test (χ2 = 4.344...

Role of MicroRNAs in Insect Host–Microorganism Interactions

Asgari, Sassan
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 15/08/2011 EN
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26.97%
MicroRNAs (miRNAs) have appeared as important regulators of various biological processes including development, cancer, immunity, and host–microorganism interactions. Accumulating evidence demonstrates the differential expression of host miRNAs upon infection by various microorganisms and the involvement of microorganism-encoded miRNAs in host manipulation. Some of these alterations could be part of a host response to an infection to limit replication and dissemination of the microorganism or, conversely, due to manipulation of the host miRNA pathway by the microorganism to facilitate its replication. Insights into the role of miRNAs in host defense responses and host manipulation by microorganisms will enable a better understanding of host–microorganism interactions.

Impact of Pesticide Contamination on Aquatic Microorganism Populations in the Littoral Zone

Lew, S.; Lew, M.; Biedunkiewicz, A.; Szarek, J.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
EN
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26.69%
The effect of pesticide contamination of the littoral zone on the population of bacteria and fungi was analyzed using the example of a eutrophic water reservoir exposed for >30 years to the influence of expired crop-protection chemicals, mainly DDT. For three consecutive years, quantity analyses of bacteria and fungi were conducted and the composition of the microorganism population analyzed against seasonal dynamics. Mold and yeast-like fungi were also isolated and identified. Within the Bacteria domain, in addition to the large groups of microorganisms (Alphaprotobacteria, Betaprobacteria, and Gammaproteobacteria, Actinobacteria, and Cytophaga-Flavobacterium), the analysis also involved the presence of bacteria predisposed to degraded pesticides in natural environments: Pseudomonas spp. and Alcaligenes spp. The quantity dynamics of aquatic microorganisms indicated that bacteria and fungi under the influence of long-term exposure to DDT can adapt to the presence of this pesticide in water. No modifying effect of DDT was observed on the quantity of microorganisms or the pattern of seasonal relationships in the eutrophic lake. Changes were shown in the percentage share of large groups of bacteria in the community of microorganisms as was an effect of contamination on the species diversity of fungi. The data show the effectiveness of aquatic microorganism–community analyses as a tool for indicating changes in the water environment caused by pesticide contamination.

Effects of Deep Tillage and Straw Returning on Soil Microorganism and Enzyme Activities

Ji, Baoyi; Hu, Hao; Zhao, Yali; Mu, Xinyuan; Liu, Kui; Li, Chaohai
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
26.9%
Two field experiments were conducted for two years with the aim of studying the effects of deep tillage and straw returning on soil microorganism and enzyme activity in clay and loam soil. Three treatments, (1) conventional tillage (CT), shallow tillage and straw returning; (2) deep tillage (DT), deep tillage and straw returning; and (3) deep tillage with no straw returning (DNT), were carried out in clay and loam soil. The results showed that deep tillage and straw returning increased the abundance of soil microorganism and most enzyme activities. Deep tillage was more effective for increasing enzyme activities in clay, while straw returning was more effective in loam. Soil microorganism abundance and most enzyme activities decreased with the increase of soil depth. Deep tillage mainly affected soil enzyme activities in loam at the soil depth of 20–30 cm and in clay at the depth of 0–40 cm. Straw returning mainly affected soil microorganism and enzyme activities at the depths of 0–30 cm and 0–40 cm, respectively.

Dynamics of a microorganism moving by chemotaxis in its own secretion

Sengupta, Ankush; van Teeffelen, Sven; Löwen, Hartmut
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.82%
The Brownian dynamics of a single microorganism coupled by chemotaxis to a diffusing concentration field which is secreted by the microorganism itself is studied by computer simulations in spatial dimensions $d=1,2,3$. Both cases of a chemoattractant and a chemorepellent are discussed. For a chemoattractant, we find a transient dynamical arrest until the microorganism diffuses for long times. For a chemorepellent, there is a transient ballistic motion in all dimensions and a long-time diffusion. These results are interpreted with the help of a theoretical analysis.; Comment: 10 pages and 5 figures (Revised and improved version)

Quantum superposition, entanglement, and state teleportation of a microorganism on an electromechanical oscillator

Li, Tongcang; Yin, Zhang-Qi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 12/09/2015
Relevância na Pesquisa
26.82%
Schr\"odinger's thought experiment to prepare a cat in a superposition of both alive and dead states reveals profound consequences of quantum mechanics and has attracted enormous interests. Here we propose a straightforward method to create quantum superposition states of a living microorganism by putting a small bacterium on top of an electromechanical oscillator. Our proposal is based on recent developments that the center-of-mass oscillation of a 15-$\mu$m-diameter aluminium membrane has been cooled to its quantum ground state [Nature 475, 359 (2011)], and entangled with a microwave field [Science, 342, 710 (2013)]. A microorganism with a mass much smaller than the mass of the electromechanical membrane will not significantly affect the quality factor of the membrane and can be cooled to the quantum ground state together with the membrane. Quantum superposition and teleportation of its center-of-mass motion state can be realized with the help of superconducting microwave circuits. More importantly, the internal states of a microorganism, such as the electron spin of a glycine radical, can be prepared in a quantum superposition state and entangled with its center-of-mass motion. Our proposal can be realized with state-of-art technologies. The proposed setup is also a quantum-limited magnetic resonance force microscope (MRFM) that not only can detect the existence of an electron spin...