Search Results - (Author, Cooperation:G. Stacey)

2013-09-07

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Arabidopsis/drug effects/*immunology/*microbiology ; Arabidopsis Proteins/metabolism ; Cell Membrane/metabolism ; Flagellin/immunology ; Immunity, Innate/drug effects/*immunology ; Lipopolysaccharides/*immunology/pharmacology ; Nitrogen Fixation/genetics ; Oligosaccharides/immunology/pharmacology ; Protein Kinases/metabolism ; Proteolysis ; Receptors, Pattern Recognition/metabolism ; Soybeans/immunology/microbiology ; Symbiosis

2014-01-18

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Adenosine Triphosphate/*metabolism ; Arabidopsis/genetics/*metabolism ; Arabidopsis Proteins/genetics/*metabolism ; Enzyme Activation ; Gene Expression Regulation, Plant ; Mitogen-Activated Protein Kinases/metabolism ; Mutation ; Protein Kinases/genetics/*metabolism ; Receptors, Mitogen/genetics/*metabolism ; Receptors, Purinergic P2/genetics/*metabolism ; Stress, Physiological/genetics/*physiology ; Up-Regulation

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Vand, in a mathematical treatment of the problem, suggested that at the wall of the tube through which a suspension is flowing, there would be a layer of the liquid phase having a thickness dependent only upon the particle diameter of the solid phase. Under certain conditions, therefore, the ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Details of the mechanism generating the maser emission in astrophysical sources (megamaser galaxies and, in our own galaxy, star formation regions and winds from evolved stars) are still uncertain. For the megamaser galaxies a good correlation exists between OH maser luminosity and the square of ...

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] In our opinion it is not justifiable to expand equation (2) in Hughes's communication to terms beyond the first power of c and to expect it to apply to higher concentrations than that postulated by Einstein, especially as he deliberately neglected the effects of interparticle collisions. ...

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0005-2744

(Purification) ; Cibacron Blue-Sepharose ; Glutamine synthetase

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0003-9861

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Physics

Electronic Resource

0167-7799

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

1432-0614

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Abstract Recombinant fusion proteins offer important new therapeutic approaches for the future. This report describes the use of three different genetic strategies (i.e. “mono-”, “bi-” and “tri-cistronic” vectors) to achieve stable secretion from BHK cells of a glycosylated antibody-cytokine fusion protein designed for use in anti-tumour therapy. It describes selection of a robust and effective production cell line based on stability of secretion of the product, quality of mRNA and protein products and performance in in vitro bioassays for potency. The data obtained at this stage were utilised in the selection of a suitable candidate production cell line. The relative productivity and general performance of the cells in stirred tank and fixed bed culture systems indicated that a variety of cell culture technologies provided robust tools for production of a highly selected cell clone. Consistency of the product glycosylation was determined by analysis of released oligosaccharides using matrix-assisted laser desorption ionisation – time of flight mass spectrometry and high-performance anion exchange chromatography. These investigations showed consistent expression of three glycoforms of the fusion protein which varied in their relative proportions in different culture systems and at different time points in a fixed bed reactor with continuous perfusion. In conclusion, this study dealt with a range of important scientific and technical issues which are essential for regulatory approval and commercial success of a recombinant protein and elucidates some useful markers for process development for similar recombinant biologicals.

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] In recent work we have found it convenient to plot the value 1 against the volumetric con-*)r centration c for stable suspensions of spheres, and have obtained a straight line. The results of other workers were treated in this way, the data used including those obtained from rising sphere, ...

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] This communication describes the properties of one of the more active compounds in the series, I.C.I. 47,776 (I, R = methyl, X = 4-fluoro), which may be prepared by condensation of 4-fluorobenzaldehyde with 3-acetyl-4-hydroxy-2-oxo-2 : 5-dihydrothiophen under either acidic or basic conditions3. It ...

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Our initial observation was that 25 mg/kg of ethyl 4-(4-bromophenyl)thiazol-2-ylacetate, ICI 52,722 (I), given by mouth daily, reduced the inflammation associated with the development of both "primary" and "secondary" lesions in rats with adjuvant-induced arthritis. Compound ICI 54,450, ...

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1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Sir In 1981, Nelson-Rees et al. found that many cell lines had been unwittingly switched or cross-contaminated with HeLa cells. Despite that warning, the number of published cases of cross-contamination is still increasing. Reference culture collections use techniques ...

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1432-072X

Lipid A ; 2,3-Diamino-2,3-dideoxy-glucose ; Slow-growing rhizobia ; Fast growing rhizobia ; Phylogeny

Springer Online Journal Archives 1860-2000

Biology

Abstract Lipid A's from two Bradyrhizobium species and from the phylogenetically closely related species “Pseudomonas carboxydovorans” were found to contain 2,3-diamino-2,3-dideoxy-glucose as lipid A backbone sugar. In contrast, three representatives of the genus Rhizobium, as well as the phylogenetically related species Agrobacterium tumefaciens, contain solely glucosamine as lipid A backbone sugar. These findings suppor independent studies on the phylogenetical relatedness based on 16S rRNA-data of the genus Bradyrhizobium with “Pseudomonas carboxydovorans“ and Rhodopseudomonas palustris, which form a tight phylogenetical cluster and which all contain the 2,3-diamino-2,3-dideoxy-glucose-containing lipid A. The relatedness of these species to the glucosamine-containing species of the genus Rhizobium and to Agrobacterium tumefaciens is rather distant as documented by 16S rRNA studies.

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1573-1472

Springer Online Journal Archives 1860-2000

Geosciences

Physics

Abstract Wind tunnel tests have been conducted on a 1:75 scale model of a Sitka spruce forest in a correctly scaled turbulent boundary-layer flow. 12000 tree models were manufactured with mass, flexibility and aerodynamic drag characteristics chosen to give dynamical similarity with typical 15 m trees in a 30ms−1 gale. To measure the dynamic response of a sample tree, set within this model forest, a miniature, fast response strain-gauge balance was designed and built. Linked to a computer for on-line data sampling, this balance provided measurements of the fluctuating along-wind and acrosswind components of the overturning moment at ground level, leading to values of mean and extreme moments and the frequency spectrum of the sway motion. Associated measurements of local wind flow characteristics were made with hot-wire anemometers and a laser anemometer. The response of the tree has the characteristics of classical lightly damped vibration and there is evidence that resonant sway motion increases the extreme overturning moments significantly above the values produced by wind gust forces alone.

Electronic Resource

1573-0778

Springer Online Journal Archives 1860-2000

Biology

Medicine

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

1573-0778

biosafety ; insect cells ; containment ; risk ; virus ; mycoplasma

Springer Online Journal Archives 1860-2000

Biology

Medicine

Process Engineering, Biotechnology, Nutrition Technology

Conclusions The hazards posed to the environment by the accidental release of baculovirus expression vectors can be put into perspective by the results obtained from experiments in which AcNPV was released deliberately into the field (Bishop et al., 1992). Polyhedrin positive viruses will persist in soil and on leaf surfaces for periods comprising weeks and months. However, polyhedrin negative viruses (similar to those used as expression vectors) do not survive in similar situations. In consequence, accidental release of baculovirus expression vectors poses negligible hazard. The risk of such a release will largely depend on the skill of the operators. This does not take into account the hazard posed by the recombinant product which is being made by the virus-infected insect cell. Synthesis of a mammalian-specific toxin, of course, would require particularly careful manipulation of the virus-infected cell culture. The fact that insect cell lines represent an undefined risk, in terms of carriage of adventitious agents means that their containment should be maintained at a minimum of the European containment level 2. Where the tissue of origin has a high risk of infection with human pathogens or where cells may have been used in a virus culture laboratory then appropriate testing is advisable. Careful risk assessment respecting the scale of work and whole procedures (in addition to individual assessment of agents and reagents) will ensure safe working conditions for laboratory staff. If applied properly safety procedures will also succeed in encouraging clean, efficient and well documented work procedures which are synonymous with the economical use of time and resources and good science.

Electronic Resource

1572-9559

Spectrometer ; Infrared Astronomy ; Infrared Techniques ; Detector Array ; Cryogenic Electronics ; Fabry-Perot ; Cryogenic ; Imaging ; Instrument Function

Springer Online Journal Archives 1860-2000

Physics

Abstract FIFI is an imaging spectrometer with two or three Fabry-Perot interferometers (FPI) in series for airborne astronomical observations in the far-infrared range (λ=40...200μm). It employs 5×5 arrays of photoconducting detectors and offers spectral resolutions as small as 2km/s. Resolution and bandwidth can be set over a wide range to match a variety of astronomical sources. Cryogenic optics minimizes thermal background radiation and provides for in-flight step tunable spatial resolution. At 158 μm wavelength the background-limited NEP is 3 × 10-15W/ℚHz at 40 km/s resolution and with two FPI's; with three FPI's the expected NEP is ≤10-15W√Hz at 5 km/s resolution. The frequency-chopping mode of the high-resolution Fabry-Perot allows for line detection in extended objects. Absolute internal flux calibration ensures adequate “flat fielding” of the array elements.

Electronic Resource

1572-9559

Infrared Astronomy ; Infrared Techniques ; Photoconductive Detector Array ; Cryogenic Electronics

Springer Online Journal Archives 1860-2000

Physics

Abstract We have constructed and used two dimensional arrays of both unstressed and stressed Ge:Ga photoconductive detectors for far-infrared astronomy from the Kuiper Airborne Observatory (KAO). The 25 element (5×5) arrays are designed for a new cryogenically cooled spectrometer, the MPE/UCB Far-Infrared Imaging Fabry-Perot Interferometer (FIFI). All of the pixels for the stressed array performed well on the first flights with FIFI; 25% of the detectors in the array are more sensitive than our best single element detector, with background limited noise equivalent powers (NEPs)≲3.0×10−15 W Hz−1/2 at 158 μm and 40 km s−1 spectral resolution. The average array element performs within±15% of this value. With a bias field of 0.1 V/cm, the average detector response is 20±6 Amp/Watt at 158 μm. The cutoff wavelength and response also compare well with our single element detectors. The unstressed array delivers significantly better performance than our single element detector due to the lower thermal background in the new spectrometer. The average background limited NEp at 88 μm and 35 km s−1 spectral resolution is ∼7×10−15 W Hz−1/2. The least sensitive pixel is only 40% less sensitive. The unstressed array response at 88 μm with a bias field of 1 V/cm is 5±1 Amp/Watt. Twenty four of the 25 elements worked on the first flights-on subsequent flights all channels have worked. Some of the exciting new science possible with far-infrared detector arrays is also discussed.

Electronic Resource

1573-5036

Bradyrhizobium ; competitiveness ; Glycine max ; N2 fixation ; Nod metabolites ; symbiosis

Springer Online Journal Archives 1860-2000

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Abstract Soybean is the most important leguminous crop in Brazil and the nitrogen required for plant growth is supplied byBradyrhizobium bacteria through the symbiotic relation established by the inoculation process. Since 1992, two new strains, CPAC 7 and CPAC 15, which have been shown to increase yields in several field experiments, have been recommended in Brazilian commercial inoculants. CPAC 15 is a natural variant of theB. elkanii SEMIA 566 strain, and was isolated after several years of adaptation to a Brazilian Cerrado soil, while CPAC 7 is a variant ofB. japonicum strain CB 1809, selected under laboratory conditions for higher nodulation and yield. The comparison between parental and variant strains, under greenhouse conditions, showed that both CPAC 15 and CPAC 7 increased N2 fixation rates in relation to the parental strains. The better performance of CPAC 15 was related to an increase in nodule efficiency (mg N2 fixed mg-1 nodule) while with CPAC 7 the higher N2 fixation rates were due to increased nodulation. Both CPAC 15 and CPAC 7 increased nodule occupancy, when co-inoculated at a ratio of 1:1 withB. elkanii 29w, in relation to their parental strains. Variant strains also differed from parental in their ability to increase numbers of root hairs (Hai phenotype) either when inoculated onto plants, or when supernatants of bacteria exposed to seed exudates were used as inoculants. This results lead to the hypothesis that a modification in some of the “common” nodulation genes had occurred. However, the increase in Hai phenotype with CPAC 7 was dependent on the soybean cultivar, indicating a possible alteration in some genotypic specific nodulation gene. Apparently, there were no differences in Nod metabolites produced by strains CPAC 15 and SEMIA 566, but a more detailed chemical analysis would be required to rule out subtle differences. On the contrary, significant differences were found between CPAC 7 and the parental strain CP 1809, in the profile of Nod metabolites. Consequently, it may be possible that diffusable molecules, responsible for Hai phenotype, would be related to nodulation ability, competiviveness, and N2 fixation, resulting in the higher yields that have been associated with CPAC 7 and CPAC 15. For the CPAC 7 strain, the increase in Hai phenotype could be atributed to the differences found in the Nod molecules. Consequently, a high degree of physiological and genetic variability can result from the adaptation of rhizobial strains to the soil. Also, this variability can be found under laboratory conditions, when searching single colonies with specific properties. ei]Section editor: R O D Dixon

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