Porous Media Matric Potential and Water Content Measurements During Parabolic Flight

Control of water and air in the root zone of plants remains a challenge in the microgravity environment of space. Due to limited flight opportunities, research aimed at resolving microgravity porous media fluid dynamics must often be conducted on Earth. The NASA KC-135 reduced gravity flight program offers an opportunity for Earth-based researchers to study physical processes in a variable gravity environment. The objectives of this study were to obtain measurements of water content and matric potential during the parabolic profile flown by the KC-135 aircraft. The flight profile provided 20–25 s of microgravity at the top of the parabola, while pulling 1.8 g at the bottom. The soil moisture sensors (Temperature and Moisture Acquisition System: Orbital Technologies, Madison, WI) used a heat-pulse method to indirectly estimate water content from heat dissipation. Tensiometers were constructed using a stainless steel porous cup with a pressure transducer and were used to measure the matric potential of the medium. The two types of sensors were placed at different depths in a substrate compartment filled with 1–2 mm Turface (calcined clay). The ability of the heat-pulse sensors to monitor overall changes in water content in the substrate compartment decreased with water content. Differences in measured water content data recorded at 0, 1, and 1.8 g were not significant. Tensiometer readings tracked pressure differences due to the hydrostatic force changes with variable gravity. The readings may have been affected by changes in cabin air pressure that occurred during each parabola. Tensiometer porous membrane conductivity (function of pore size) and fluid volume both influence response time. Porous media sample height and water content influence time-to-equilibrium, where shorter samples and higher water content achieve faster equilibrium. Further testing is needed to develop these sensors for space flight applications

Paper Session I-A - Development of Technology and Experimental Designs for Plant Growth Studies in Space

Plants will be a critical component of future Bioregenerative Life Support Systems that will be implemented on long duration space missions. We describe here a novel microgravity-rated plant growth apparatus that is targeted for use on the International Space Station (ISS) in the 2004-2005 timeframe. The system contains six modular units capable of utilizing either porous tube and/or substrate-based nutrient delivery approaches. Heat pulse moisture sensors are used to both monitor and control root zone wetness levels. In addition, a fixed-feed water delivery algorithm is available which meters out appropriate levels of water based upon plant life cycle stage. Fifty miniature color cameras will image the plant specimens throughout the experiment, permitting real-time assessments of plant performance over time. Alternative experimental strategies suitable for implementation on the ISS are discussed

Low Cost Industrial Production of Coagulation Factor IX Bioencapsulated in Lettuce Cells for Oral Tolerance Induction in Hemophilia B

Antibodies (inhibitors) developed by hemophilia B patients against coagulation factor IX (FIX) are challenging to eliminate because of anaphylaxis or nephrotic syndrome after continued infusion. To address this urgent unmet medical need, FIX fused with a transmucosal carrier (CTB) was produced in a commercial lettuce (Simpson Elite) cultivar using species specific chloroplast vectors regulated by endogenous psbA sequences. CTB-FIX (~1mg/g) in lyophilized cells was stable with proper folding, disulfide bonds and pentamer assembly when stored ~2 years at ambient temperature. Feeding lettuce cells to hemophilia B mice delivered CTB-FIX efficiently to the gut immune system, induced LAP+ regulatory T cells and suppressed inhibitor/IgE formation and anaphylaxis against FIX. Lyophilized cells enabled 10-fold dose escalation studies and successful induction of oral tolerance was observed in all tested doses. Induction of tolerance in such a broad dose range should enable oral delivery to patients of different age groups and diverse genetic background. Using Fraunhofer cGMP hydroponic system, ~870 kg fresh or 43.5 kg dry weight can be harvested per 1000 ft2 per annum yielding 24,000–36,000 doses for 20-kg pediatric patients, enabling first commercial development of an oral drug, addressing prohibitively expensive purification, cold storage/transportation and short shelf life of current protein drugs

An evaluation of the heat balance method for direct transpiration measurement

The measurement of sap flow has been sought after for many years. Various methods have been devised to accomplish this task, one of which is the heat balance method. This method is non-invasive and accurate, but its simplifying assumptions were questionable and needed to be critically examined. This study evaluated the heat balance method and sap flow gauges. The method yielded satisfactory results when compared to the calibration system. The satisfactory results were over a limited range, which exemplified the necessity for the gauges to be calibrated. The heat balance method's simplified heat transfer analysis does not reflect the complexity of the physical situation. Sap flow gauge improvements were suggested

Evaluation of TB activity in immunized mouse sera by SMFA: one vaccine dose.

a<p>The proportion (percentage) of mosquitoes infected.</p>b<p>Median number of oocysts per mosquito (range).</p>c<p>% reduction = (mean control oocyst – mean test oocyst) ÷ mean control oocyst)*100.</p>d<p>Control.</p>*<p>CP – coat protein.</p

A Plant-Produced Pfs25 VLP Malaria Vaccine Candidate Induces Persistent Transmission Blocking Antibodies against Plasmodium falciparum in Immunized Mice

Contains fulltext : 128628.pdf (publisher's version ) (Open Access

Pfs25-CP VLP particle analysis.

<p>(A) Negative stain transmission electron micrograph of Pfs25-CP VLPs shows highly uniform particles of 19.3±2.4 nm in diameter. (B) Transmission electron micrograph of Pfs25-CP VLPs labeled with anti-Pfs25 and gold-labeled anti-mouse antibodies confirms the presence of Pfs25 on the particles. (C) DLS histogram showing a narrow size distribution for Pfs25-CP VLPs. The average hydrodynamic radius is ∼14 nm with a polydispersity of <15%. (D) Analytical SEC showing a single, major eluting species confirmed by Western blot analysis (not shown) to be Pfs25-CP VLP. The void volume of the SRT 1000 column (range 7.5 MDa –50 kDa) is indicated by (a) molecular weight standards indicated by (b) for thyroglobulin, (c) for BSA and (d) for uracil.</p

Schematic diagram of the ‘launch’ vector.

<p>Following agroinfiltration of plants, the sequence between the left border (LB) and the right border (RB) of the plasmid vector is transferred from <i>Agrobacteria</i> into plant cells where expression of the engineered TMV genome is driven by the Cauliflower mosaic virus (CaMV) 35S promoter. TMV replicase then drives amplification of primary transcript, and Pfs25-CP accumulation is then driven by the TMV CP subgenomic promoter (light blue box). Movement protein (MP) facilitates cell-to-cell transfer of viral sequences and is driven by the MP subgenomic promoter (dark blue box).</p

Anti-Pfs25 IgG responses in mice determined by ELISA.

<p>(A) Average anti-Pfs25 IgG titers from mice immunized with two doses of either 1.0 µg (circles) or 0.1 µg (squares) of Pfs25-CP VLPs, each with (open symbols) or without (filled symbols) Alhydrogel®, or 5.0 µg of CP only (black line). (B) Average anti-Pfs25 IgG titers from mice immunized with two doses of either 1.0 µg (circles), 0.1 µg (squares) or 0.01 µg (diamonds) of Pfs25-CP VLPs with Alhydrogel®. (C) Average anti-Pfs25 IgG titers elicited by a single administration of Pfs25-CP VLPs with Alhydrogel® at antigen doses ranging from 0.2–25 µg. Data are represented as average values per group of mice ± standard error of the mean.</p

Evaluation of TB activity in immunized mouse sera by SMFA: two vaccine doses.

a<p>The proportion (percentage) of mosquitoes infected.</p>b<p>Median number of oocysts per mosquito (range).</p>c<p>% reduction = (mean control oocyst – mean test oocyst) ÷ mean control oocyst)*100.</p>d<p>Control.</p>*<p>ns – not significant.</p>**<p>CP – coat protein.</p