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Search Results: 1 - 10 of 75826 matches for " Robert Michael;Reis "
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Quantification of natural populations of Gluconacetobacter diazotrophicus and Herbaspirillum spp. In sugar cane (Saccharum spp.) Using differente polyclonal antibodies
Silva-Froufe, Lúcia Gracinda da;Boddey, Robert Michael;Reis, Veronica Massena;
Brazilian Journal of Microbiology , 2009, DOI: 10.1590/S1517-83822009000400018
Abstract: the species gluconacetobacterdiazotrophicus, herbaspirillum seropedicae and h. rubrisubalbicans are endophytic n2-fixing [diazotrophic] bacteria which colonise not only roots, but also the aerial tissue of sugar cane. however, the technique most commonly used to quantify the populations of these microbes in plants is by culturing serial dilutions of macerates of plant tissues in n free semi-solid media which are only semi-selective for the species/genera [the most probable number (mpn) technique] and each culture must be further subjected to several tests to identify the isolates at the species level. the use of species-specific polyclonal antibodies with the indirect elisa (enzyme-linked immunosorbent assay) can be an alternative which is rapid and specific to quantify these populations of bacteria. this study was performed to investigate the viability of adapting the indirect elisa technique to quantify individually the populations of these three species of diazotroph within the root and shoot tissues of sugarcane. the results showed that species-specific polyclonal antibodies could be obtained by purifying sera in protein-a columns which removed non-specific immuno-globulins. it was possible to quantify the three bacterial species in the brazilian sugarcane variety sp 70-1143 in numbers above 105 cells per g fresh weight in roots, rhizomes and leaves. the numbers of the different bacterial species evaluated using the elisa technique were found to be higher than when the same populations were evaluated using the mpn technique, reaching 1400 times greater for g. diazotrophicus and 225 times greater for herbaspirillum spp. these results constitute the first quantification of herbaspirillum using immunological techniques.
Eficiência agron?mica de estirpes de rizóbio em feij?o-caupi cultivado na regi?o da Pré-Amaz?nia Maranhense
Gualter, Régia Maria Reis;Boddey, Robert Michael;Rumjanek, Norma Gouvêa;Freitas, Ant?nio Carlos Reis de;Xavier, Gustavo Ribeiro;
Pesquisa Agropecuária Brasileira , 2011, DOI: 10.1590/S0100-204X2011000300011
Abstract: the objective of this work was to evaluate the agronomic efficiency of rhizobia strains for inoculation, in field conditions, of the cowpea brs guariba cultivar. experiments were carried out in two areas in santa luzia do paruá, maranh?o state, brazil, in the pre-amazon region, in 2009. the br 3299, br 3262, inpa03-11b bradyrhizobium strains, an absolute control, and a nitrogen treatment (80 kg ha-1 n) weretested. at30 and 50 days after emergence (dae) of plants assesments were made. at 65 dae, grainyield was evaluated. the number and dry weight of nodules, shoot dry mass, relative efficiency, and n accumulation in shoots were evaluated. all strains provided higher values for number and dry weight of nodules, and higher productivity in comparsion to the absolute control, without inoculation and urea, in the two areas. regarding shoot dry matter, relative efficiency, and n accumulation in shoots, br 3299 differed significantly from the absolute control, at 30 dae, in one of the farms. cowpea yield responds positively to inoculation with strains, especially strain br 3299.
Phonon Spectroscopy with Sub-meV Resolution by Femtosecond X-ray Diffuse Scattering
Diling Zhu,Aymeric Robert,Tom Henighan,Henrik T. Lemke,Matthieu Chollet,J. Michael Glownia,David A. Reis,Mariano Trigo
Physics , 2015, DOI: 10.1103/PhysRevB.92.054303
Abstract: We present a reconstruction of the transverse acoustic phonon dispersion of germanium from femtosecond time-resolved x-ray diffuse scattering measurements at the Linac Coherent Light Source. We demonstrate an energy resolution of 0.3 meV with momentum resolution of 0.01 nm^-1 using 10 keV x-rays with a bandwidth of ~ 1 eV. This high resolution was achieved simultaneously for a large section of reciprocal space including regions closely following three of the principle symmetry directions. The phonon dispersion was reconstructed with less than three hours of measurement time, during which neither the x-ray energy, the sample orientation, nor the detector position were scanned. These results demonstrate how time-domain measurements can complement conventional frequency domain inelastic scattering techniques.
Coming to Terms with Complexity: Limits to a Reductionist View of Aging
Robert J. Shmookler Reis
Frontiers in Genetics , 2012, DOI: 10.3389/fgene.2012.00149
What is Aging?
Michael R. Rose,Thomas Flatt,Joseph L. Graves,Lee F. Greer,Daniel E. Martinez,Margarida Matos,Laurence D. Mueller,Robert J. Shmookler Reis,Parvin Shahrestani
Frontiers in Genetics , 2012, DOI: 10.3389/fgene.2012.00134
G306.3-0.9: A newly discovered young galactic supernova remnant
Mark Reynolds,Shyeh Loi,Tara Murphy,Jon Miller,Dipankar Maitra,Kayhan Gultekin,Neil Gehrels,Jamie Kennea,Michael Siegel,Jonathan Gelbord,Paul Kuin,Vanessa Moss,Sarah Reeves,William Robbins,Bryan Gaensler,Rubens Reis,Robert Petre
Physics , 2013, DOI: 10.1088/0004-637X/766/2/112
Abstract: We present X-ray and radio observations of the new Galactic supernova remnant (SNR) G306.3-0.9, recently discovered by Swift. Chandra imaging reveals a complex morphology, dominated by a bright shock. The X-ray spectrum is broadly consistent with a young SNR in the Sedov phase, implying an age of 2500 yr for a distance of 8 kpc, plausibly identifying this as one of the 20 youngest Galactic SNRs. Australia Telescope Compact Array (ATCA) imaging reveals a prominent ridge of radio emission that correlates with the X-ray emission. We find a flux density of ~ 160 mJy at 1 GHz, which is the lowest radio flux recorded for a Galactic SNR to date. The remnant is also detected at 24microns, indicating the presence of irradiated warm dust. The data reveal no compelling evidence for the presence of a compact stellar remnant.
Migratory Behavior of Franklin’s Gulls (Larus pipixcan) in Peru  [PDF]
Joanna Burger, Michael Gochfeld, Robert Ridgely
Energy and Power Engineering (EPE) , 2010, DOI: 10.4236/epe.2010.23021
Abstract: Information on the migratory pathways for birds is essential to the future citing of wind power facilities, particularly in off-shore waters. Yet, relatively little is known about the coastal or offshore migratory behavior of most birds, including Franklin’s gulls (Larus pipixcan), a long-distant migrant. We report observations along the coast of Peru made in November 2008 to determine where birds concentrated. Wind facilities can not avoid regions of high avian activity without knowing where that activity occurs. Migrant flocks of 250 to 50,000 were observed on coastal farmfields, dumps and estuaries, on beaches and mudflats, and up to 45 km offshore. Bathing and foraging flocks ranged in size from 20 to 500 birds, and most flocks were monospecific, with occasional grey-headed (Larus cirrocephalus) and band-tailed (L. belcheri) on the periphery. While previous notes report Franklin’s gulls foraging coastally, we found flocks feeding up to 45 km offshore by diving for prey or feeding on the water. The relative percentage of birds of the year varied in migrant flocks from zero to 14%, with lower numbers of young foraging aerially on insects (only 1%). The percentage of young feeding over the ocean decreased with increasing distance from shore; no young of the year were recorded at 36-44 km offshore. While there were large flocks of Franklin’s gulls resting on the water inshore, the number of gulls foraging offshore did not decline up to 45 km offshore. The presence of foraging flocks of Franklin’s gulls out to 45 km offshore, and occupying space from 0 to 20 m above the water, suggests that they would be vulnerable to offshore anthropogenic activities, such as offshore drilling and wind facilities.
Escherichia coli superoxide dismutase expression does not change in response to iron challenge during lag phase: Is the ferric uptake regulator to blame?  [PDF]
Robert L. Bertrand, Michael O. Eze
Advances in Enzyme Research (AER) , 2013, DOI: 10.4236/aer.2013.14014
Abstract: Intracellular iron levels and the expression of superoxide dismutase (SOD) and hydroperoxidase (HP) are regulated in Gram-negative bacteria by the iron(II)-activated ferric uptake regula- tor (Fur). We have previously observed that the expression of SOD in exponential phase Escherichia coli is dependent upon the redox state of iron in media, consistent with the ferrous specificity of Fur regulation (Bertrand et al., Med. Hypotheses 78: 130 - 133, 2012). Through the non-denaturing electrophoretic technique we have determined the Escherichia coli expression profiles of SOD and HP in response to iron challenge throughout lag, logarithmic, and stationary phases of replication. Lag phase SOD presented an unusual expression profile such that SOD expression was unresponsive to iron challenge, analogous to observations of mutant strains lacking Fur and of E. coli incubated in iron-deplete media. Challenging Escherichia coli with iron during logarithmic phase revealed that length of exposure to oxidants is unlikely to be the cause of SOD unresponsiveness in lag phase. HP activity was up-regulated two- or three-fold throughout all growth phases in response to iron challenge, but did not present redox- or growth phase-specific outcomes in a manner analogous to SOD. We hypothesize that low Fur levels during lag phase are responsible for unresponsive SOD.
Radiation-Induced Lung Cancers in Murine Models  [PDF]
Leena Rivina, Michael Davoren, Robert H. Schiestl
Advances in Lung Cancer (ALC) , 2014, DOI: 10.4236/alc.2014.32006

Radiation therapy is a key weapon in the modern arsenal of cancer treatment. However, this effective treatment comes with risks of its own, and the sheer number of patients that undergo radiation as a part of their therapy regimen is only increasing. As this number increases, so does the incidence of secondary, radiation-induced neoplasias, creating a need for therapeutic agents targeted specifically towards reduction in the incidence of and treatment of these cancers. Development and efficacy testing of these agents requires not only extensive in vitro testing, but also a set of reliable animal models to accurately recreate the complex situations of radiation-induced carcinogenesis. The laboratory mouse Mus musculus remains the most relevant animal model in cancer research due to the molecular and physiological similarities it shares with man, its small size and high rate of breeding in captivity, and its fully sequenced genome. In this work, we review relevant M. musculusinbred and F1 hybrid animal models, as well as methods of induction of radiation-induced lung cancers. Associated molecular pathologies are also included.

Modifying Polyacrylamide Background Color for the Nitroblue Tetrazolium-Based Superoxide Dismutase Staining Assay  [PDF]
Robert Louis Bertrand, Michael Okechukwu Eze
Advances in Enzyme Research (AER) , 2014, DOI: 10.4236/aer.2014.22008
Abstract: The reduction of nitroblue tetrazolium by superoxide radicals generated from photo-reactive riboflavin has been in use for more than four decades to detect superoxide dismutase (SOD) on nondenaturing polyacrylamide gels. SOD research in medicine and biochemistry has warranted the development of multiple assay variants to overcome specific experimental constraints or to combine the SOD assay with other enzyme assays. Fine-tuning reagent concentrations to effectively visualize bands continue to be a major research obstacle in assay development. Herein we describe a straightforward technique to reliably adjust the background color of polyacrylamide gels without compromising assay efficacy. Low micromolar to low millimolar concentrations of yellow riboflavin can be mixed with the blue of reduced nitroblue tetrazolium to controllably produce blue, purple, yellow-brown, or yellow gel backgrounds. The advantage of this technique is that the assay is not modified by the introduction of new reagents. Quantitative reliability of these alternative stains was assessed by plotting determined band intensity values against known enzyme loads. The correlation (R2) values of trial averages were compared against the average correlation of the standard 0.028 mM riboflavin solution using pooled standard deviation and Student’s T-test at 95% confidence. Assay sensitivity was assessed by comparing lowest possible visible enzyme load of the experimental stains with the 0.028 mM riboflavin standard. No difference in the quantitative reliability was found in any riboflavin concentration. The minimum reliable sensitivity of the assay was found to be 10 ng for each concentration of riboflavin. This technique has already been employed to analyze SOD protein expression levels in extracts of Escherichia coli (Bertrand et al., Med Hypotheses 2012; 78:130-133, 2012; Bertrand & Eze, Adv. Enz. Res., 1: 132-141, 2013).
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