Bacterial polysaccharides have numerous clinical or industrial uses. Recombinant plants could offer the possibility of producing bacterial polysaccharides on a large scale and free of contaminating ...bacterial toxins and antigens. We investigated the feasibility of this proposal by cloning and expressing the gene for the type 3 synthase (cps3S) of Streptococcus pneumoniae in Nicotinia tabacum, using the pCambia2301 vector and Agrobacterium tumefaciens-mediated gene transfer. In planta the recombinant synthase polymerised plant-derived UDP-glucose and UDP-glucuronic acid to form type 3 polysaccharide. Expression of the cps3S gene was detected by RT-PCR and production of the pneumococcal polysaccharide was detected in tobacco leaf extracts by double immunodiffusion, Western blotting and high-voltage paper electrophoresis. Because it is used a component of anti-pneumococcal vaccines, the immunogenicity of the plant-derived type 3 polysaccharide was tested. Mice immunised with extracts from recombinant plants were protected from challenge with a lethal dose of pneumococci in a model of pneumonia and the immunised mice had significantly elevated levels of serum anti-pneumococcal polysaccharide antibodies. This study provides the proof of the principle that bacterial polysaccharide can be successfully synthesised in plants and that these recombinant polysaccharides could be used as vaccines to protect against life-threatening infections.
The results of several studies of the humanities and social sciences in undergraduate engineering education are presented and discussed. The first chapter explains the value of humanities and social ...sciences coursework and describes briefly some of the obstacles confronting efforts to improve it. The second chapter summarizes the findings of two empirical studies, one of engineering programs policies and one of engineering students' choice of humanities and social science courses. The third chapter briefly describes 13 programs, or parts of programs, that provide liberal education to engineering students in innovative ways. With special attention given to the "typical" engineering school, chapter four suggests criteria for improving humanities and social science coursework and steps to help create a climate and mechanisms to support that improvement. Contains 30 references. (MSE)
Reports describing the effect of interferon-gamma (IFNgamma) on interleukin-1beta (IL-1beta) production are conflicting. We resolve this controversy by showing that IFNgamma potentiates IL-1beta ...release from human cells, but transiently inhibits the production of IL-1beta from mouse cells. Release from this inhibition is dependent on suppressor of cytokine signalling 1. IL-1beta and Th17 cells are pathogenic in mouse models for autoimmune disease, which use Mycobacterium tuberculosis (MTB), in which IFNgamma and IFNbeta are anti-inflammatory. We observed that these cytokines suppress IL-1beta production in response to MTB, resulting in a reduced number of IL-17-producing cells. In human cells, IFNgamma increased IL-1beta production, and this might explain why IFNgamma is detrimental for multiple sclerosis. In mice, IFNgamma decreased IL-1beta and subsequently IL-17, indicating that the adaptive immune response can provide a systemic, but transient, signal to limit inflammation.
We present a sensitive, compact detector that measures total reactive nitrogen (NO y ), as well as NO2, NO, and O3. In all channels, NO2 is directly detected by laser diode based cavity ring-down ...spectroscopy (CRDS) at 405 nm. Ambient O3 is converted to NO2 in excess NO for the O3 measurement channel. Likewise, ambient NO is converted to NO2 in excess O3. Ambient NO y is thermally dissociated at ∼700 °C to form NO2 or NO in a heated quartz inlet. Any NO present in ambient air or formed from thermal dissociation of other reactive nitrogen compounds is converted to NO2 in excess O3 after the thermal converter. We measured thermal dissociation profiles for six of the major NO y components and compared ambient measurements with other instruments during field campaigns in Utah and Alabama. Alabama measurements were made in a rural location with high biogenic emissions, and Utah measurements were made in the wintertime in unusual conditions that form high ozone levels from emissions related to oil and gas production. The NO y comparison in Alabama, to an accepted standard measurement method (a molybdenum catalytic converter/chemiluminescence instrument), agreed to within 12%, which we define as an upper limit to the accuracy of the NO y channel. The 1σ precision is <30 pptv at 1 s and <4 pptv at 1 min time resolution for all measurement channels. The accuracy is 3% for the NO2 and O3 channels and 5% for the NO channel. The precision and accuracy of this instrument make it a versatile alternative to standard chemiluminescence-based NO y instruments.
The Coupled Model Intercomparison Project phase 6 (CMIP6) HighResMIP is a new experimental design for global climate model simulations that aims to assess the impact of model horizontal resolution on ...climate simulation fidelity. We describe a hierarchy of global coupled model resolutions based on the Hadley Centre Global Environment Model 3 - Global Coupled vn 3.1 (HadGEM3-GC3.1) model that ranges from an atmosphere-ocean resolution of 130 km-1.sup." to 25 km-1/12.sup.", all using the same forcings and initial conditions. In order to make such high-resolution simulations possible, the experiments have a short 30-year spinup, followed by at least century-long simulations with constant forcing to assess drift.
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