Journal Supplement

Abstracts from Texas Tech University Health Sciences Center School of Medicine Summer Research Program from the Lubbock Campus presented at the Student Research Week in March 2018. The names in bold are the medical students who participated in this program in 2017. The author index starts after the last abstract (#26)

Measurement and modelling of photosynthetic response of pearl millet to soil phosphorus addition

There have been no studies of the effects of soil P deficiency on pearl millet (Pennisetum glaucum (L.) R. Br.) photosynthesis, despite the fact that P deficiency is the majorxonstraint to pearl millet production in most regions of West Africa. Because current photosynthesis-based crop simulation models do not explicitly take into account P deficiency effects on leaf photosynthesis, they cannot predict millet growth without extensive calibration. We studied the effects of soil addition on leaf P content, photosynthetic rate (A), and whole-plant dry matter production (DM) of non-water-stressed, 28 d pearl millet plants grown in pots containing 6.00 kg of a P-deficient soil. As soil P addition increased from 0 to 155.2 mg P kg- 1 soil, leaf P content increased from 0.65 to 7.0 g kg-1 . Both A and DM had maximal values near 51.7 mg P kg- 1 soil, which corresponded to a leaf P content of 3.2 g kg- 1. Within this range of soil P addition, the slope of A plotted against stomatal conductance (gs) tripled, and mean leaf internal CO2 concentration ([CC^];) decreased from 260 to 92 pL L~'., thus indicating that P deficiency limited A through metabolic dysfunction rather than stomatal regulation. Light response curves of A, which changed markedly with P leaf content, were modelled as a single substrate, Michaelis-Menten reaction, using quantum flux as the substrate for each level of soil P addition. An Eadie-Hofstee plot of light response data revealed that both Km, which is mathematically equivalent to quantum efficiency, and Vmax, which is the light-saturated rate of photosynthesis, increased sharply from leaf P contents of 0.6 to 3 g kg-1 , with peak values between 4 and 5 g P kg-1 . Polynomial equations relating Km and Vmax, to leaf P content offered a simple and attractive way of modelling photosynthetic light response for plants of different P status, but this approach is somewhat complicated by the decrease of leaf P content with ontogeny

Soil Phosphorus Availability and Pearl Millet Water-Use Efficiency

The effects of P and water stress on transpirational water-use efficiency (WUET) of pearl millet (Pennisetum glaucum) cv. ICTP 8203 were studied in outdoor pot and growth chamber experiments. Plants were grown outdoors under semiarid conditions in covered pots containing 85 kg of acid, P-deficient Betis sand (sandy, siliceous, thermic Psammentic Paleustalf). Pots were given 0-7.77 g P/m² (equivalent to 0-70 kg P/ha), water stressed or not stressed, and plants harvested at 14-d intervals. Significant main and interactive effects on WUET due to P level, water treatment, and harvesting date occurred. The slope of the curve relating DM to cumulative transpiration increased with P level and water stress when data from all harvests were pooled. In the growth chamber, WUET of non-water-stressed plants ranged with increasing P level from 3.22 to 9.12 g/kg at 29 d after sowing (DAS) in pots containing 6 kg soil, and from 0.84 to 9.24 g/kg at 49 DAS in pots containing 18 kg soil. The ratio of leaf net photosynthetic rate to transpiration (WUEgas) at 500 µmol/m² per s photosynthetic photon flux density (PPFD) ranged from 1.88 µg/mg for plants receiving no P to 10.25 µg/mg for those receiving 0.31 g P/6 kg soil. Between PPFD levels of 500 and 2000 µmol/m² per s plants receiving no P increased WUEgas to only 3.60 µg/mg, whereas those receiving higher levels of P increased WUEgas to as much as 18.2 µg/mg. It was concluded that water supply in semiarid environments cannot be effectively managed for improved crop production without addressing soil fertility constraints

The concealed middle?:An exploration of ordinary young people and school GCSE subject area attainment

This is the final version of the article. Available from ESRC Centre for Population Change via the link in this record.In Britain school examination results are now an annual newsworthy item. This recurrent event illustrates, and reinforces, the importance of school level qualifications. The General Certificate of Secondary Education (GCSE) is the standard qualification undertaken by pupils at the end of year 11 (age 15-16). GCSEs continue to play an important and central role in young people’s educational and employment pathways. Within the sociology of youth there has been recent interest in documenting the lives and educational experiences of ‘ordinary’ young people. There are many analyses of agglomerate (i.e. overall) school GCSE attainment. More recently attention has been focused on individual GCSE subjects. In this paper we analyse school GCSE attainment at the subject area level. This is an innovative approach and our motivation is to explore substantively interesting patterns of attainment that might be concealed in analyses of overall attainment, or attainment within individual subjects. We analyse data from the Youth Cohort Study of England and Wales using a latent variable approach. The modelling process uncovered four distinctive latent educational groups. One latent group is characterised by high levels of overall attainment, whereas another latent group is characterised by poor GCSE performance. There are two latent groups with moderate or ‘middle’ levels of GCSE attainment. These two latent groups have similar levels of agglomerate attainment, but one group performs better in science and the other performs better in arts GCSEs. Pupils study for multiple GCSEs which are drawn from a wide menu of choices. There is a large array of possible GCSE subject combinations, and results in individual GCSE subjects are highly correlated. The adoption of a latent variable approach is attractive because it handles the messy nature of the data whilst not trivialising its complexity. The paper demonstrates that a latent variable approach is practicable with large-scale social survey data, and is appealing for the analysis of more contemporaneous cohorts.The ESRC Centre for Population Change (CPC) is a joint initiative between the Universities of Southampton, St Andrews, Edinburgh, Stirling, Strathclyde, in partnership with the Office for National Statistics (ONS) and the General Register Office Scotland (GROS). The Centre is funded by the Economic and Social Research Council (ESRC) grant numbers RES-625-28-0001 and ES/K007394/1

Production, quality control, stability, and potency of cGMP-produced Plasmodium falciparum RH5.1 protein vaccine expressed in Drosophila S2 cells

Plasmodium falciparum reticulocyte-binding protein homolog 5 (PfRH5) is a leading asexual blood-stage vaccine candidate for malaria. In preparation for clinical trials, a full-length PfRH5 protein vaccine called “RH5.1” was produced as a soluble product under cGMP using the ExpreS2 platform (based on a Drosophila melanogaster S2 stable cell line system). Following development of a highproducing monoclonal S2 cell line, a master cell bank was produced prior to the cGMP campaign. Culture supernatants were processed using C-tag affinity chromatography followed by size exclusion chromatography and virus-reduction filtration. The overall process yielded >400 mg highly pure RH5.1 protein. QC testing showed the MCB and the RH5.1 product met all specified acceptance criteria including those for sterility, purity, and identity. The RH5.1 vaccine product was stored at −80 °C and is stable for over 18 months. Characterization of the protein following formulation in the adjuvant system AS01B showed that RH5.1 is stable in the timeframe needed for clinical vaccine administration, and that there was no discernible impact on the liposomal formulation of AS01B following addition of RH5.1. Subsequent immunization of mice confirmed the RH5.1/AS01B vaccine was immunogenic and could induce functional growth inhibitory antibodies against blood-stage P. falciparum in vitro. The RH5.1/AS01B was judged suitable for use in humans and has since progressed to phase I/IIa clinical trial. Our data support the future use of the Drosophila S2 cell and C-tag platform technologies to enable cGMP-compliant biomanufacture of other novel and “difficult-to-express” recombinant protein-based vaccines