Nitrogen fixation of pea and chickpea in response to drought in Saskatchewan

Non-Peer ReviewedPulse crops are economically important in cropping systems because of their ability to assimilate atmospheric nitrogen (N2). Cost of fertilizer N and an interest in developing ecologically sustainable agricultural systems has lead to an increased interest in the process of N2 fixation. In stress-free environments, legumes fix nitrogen for crop growth and high-protein seed production. However, N2 fixation in legumes is sensitive to water deficit, which restricts N supply, grain yield, and grain quality. The objective of this study was to quantify differences in N2 fixation for chickpea and pea cultivars subject to drought in the field in 2002. Measurements included biomass accumulation and leaf ureide concentration, a potential nitrogen fixation product, throughout the season. At the end of the season, natural abundance of N by fixation and yield were taken. Results will be discussed relating differences in cultivar biomass accumulation and total N fixation to N fixation products

Early supplies of available nitrogen to the seed-row as affected by fertilizer placement

Non-Peer ReviewedA field experiment was conducted at Star City, (legal location SW6-45-16-W2); Saskatchewan, Canada from May to June 2000, to measure N and P supply rates from fertilizer band to canola seed row. Ion exchange resin membrane probes (PRS™-probes) were used to measure nutrient supply rates in four treatments (80 kg/ha of urea side-band, 80 kg/ha of urea mid-row band, check/no N (side-row)/P side-banded, check/no N (mid-row)/P seed placed. The treatments were arranged in a randomized complete block design with four replications. Two anion and cation exchange resin probes (PRS™-probes) were placed in each plot in the seed-row immediately after seeding and fertilizing. The probes were allowed to remain in the field for 2 days and replaced with another set of probes every 4 days for a total of 14 days until canola emerged. Ammonium-N, nitrate-N and P supply rates were calculated based on the ion accumulated on the probes. Grain and straw yield were measured in each plot. Urea side-row band treatments had significantly higher cumulative available N supply rates than mid-row banded placement. No significant differences were observed in P supply rates. The higher N rates (120 kg N/ha) showed lower grain yield in side banding than mid-row banding treatment possibly due to seedling damage, however the earlier fluxes of N into the seed-row observed with side-banding may be an advantage at lower N rates in N deficient soils

Glycoform analysis of intact erythropoietin by MALDI FT-ICR mass spectrometry

Recombinant human erythropoietin (EPO) is a complex therapeutic glycoprotein with three N- and one O-glycosylation sites. Glycosylation of EPO influences its safety and efficacy and is defined as a critical quality attribute. Thus, analytical methods for profiling EPO glycosylation are highly demanded. Owing to the complexity of the intact protein, information about EPO glycosylation is commonly derived from released glycan and glycopeptide analysis using mass spectrometry (MS). Alternatively, comprehensive insights into the glycoform heterogeneity of intact EPO are obtained using ESI MS-based methods with or without upfront separation of EPO glycoforms. MALDI MS, typically performed with TOF mass analyzers, has been also used for the analysis of intact EPO but, due to the poor glycoform resolution, has only provided limited glycoform information. Here, we present a MALDI FT-ICR MS method for the glycosylation profiling of intact EPO with improved glycoform resolution and without loss of sialic acid residues commonly observed in MALDI analysis. Three EPO variants were characterized in-depth and up to 199 glycoform compositions were assigned from the evaluation of doubly-charged ions, without any deconvolution of the mass spectra. Key glycosylation features such as sialylation, acetylation, and N- acetyllactosamine repeats were determined and found to agree with previously reported data obtained from orthogonal analyses. The developed method allowed for a fast and straightforward data acquisition and evaluation and can be potentially used for the high-throughput comparison of EPO samples throughout its manufacturing process. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Proteomic

Recurrent Selection to Alter Grain Phytic Acid Concentration and Iron Bioavailability

Iron is an important micronutrient and Fe deficiency is a global health concern. Phytic acid inhibits Fe absorption and cannot be digested by monogastric livestock or humans. High phytate concentration in staple crops may be one of the contributing factors for the high incidence of anemia in developing countries because of its inhibiting effect on Fe absorption. In seeds, it serves as the main storage compound for P. Low phytic acid mutants (lpa) in maize (Zea mays L.) have improved Fe bioavailability, but they have poor germination. Our objective was to develop both low phytic acid (LPA) and high phytic acid (HPA) maize populations using recurrent selection and to compare seed quality and Fe bioavailability among the HPA and LPA populations and lpa mutant lines. Three cycles of selection were performed in two broad-based synthetic populations, BS11 and BS31. The resulting HPA and LPA populations were significantly different in phytic acid concentration in the BS11-derived populations (P \u3c 0.05) but not in the BSS31-derived populations (P \u3e 0.05). The BS11LPA maize population had improved seed germination (13–16%; P \u3c 0.05), and Fe bioavailability was not statistically different (P \u3e 0.05) than the lpa mutant inbred lines. We conclude that recurrent selection for phytic acid levels may be a viable approach for improving Fe bioavailability of grain while maintaining seed quality

Increased food availability raises eviction rate in a cooperative breeding mammal

In group-living mammals, the eviction of subordinate females from breeding groups by dominants may serve to reduce feeding competition or to reduce breeding competition. Here, we combined both correlational and experimental approaches to investigate whether increases in food intake by dominant females reduces their tendency to evict subordinate females in wild meerkats ($\textit{Suricata suricatta}$). We used 20 years of long-term data to examine the association between foraging success and eviction rate, and provisioned dominant females during the second half of their pregnancy, when they most commonly evict subordinates. We show that rather than reducing the tendency for dominants to evict subordinates, foraging success of dominant females is positively associated with the probability that pregnant dominant females will evict subordinate females and that experimental feeding increased their rates of eviction. Our results suggest that it is unlikely that the eviction of subordinate females serves to reduce feeding competition and that its principal function may be to reduce reproductive competition. The increase in eviction rates following experimental feeding also suggests that rather than feeding competition, energetic constraints may normally constrain eviction rates.The KMP is supported by the Universities of Cambridge, Zurich and Pretoria. Components of this research were supported by the Natural Environment Research Council (grant no. NE/G006822/1) and the European Research Council (grant no. 294494)

Iron bioavailability in two commercial cultivars of wheat: a comparison between wholegrain and white flour and the effects of nicotianamine and 2'-deoxymugineic acid on iron uptake into Caco-2 cells

Iron bioavailability in unleavened white and wholegrain bread made from two commercial wheat varieties was assessed by measuring ferritin production in Caco-2 cells. The breads were subjected to simulated gastrointestinal digestion and the digests applied to the Caco-2 cells. Although Riband grain contained a lower iron concentration than Rialto, iron bioavailability was higher. No iron was taken up by the cells from white bread made from Rialto flour or from wholegrain bread from either variety, but Riband white bread produced a small ferritin response. The results probably relate to differences in phytate content of the breads, although iron in soluble monoferric phytate was demonstrated to be bioavailable in the cell model. Nicotianamine, an iron chelator in plants involved in iron transport, was a more potent enhancer of iron uptake into Caco-2 cells than ascorbic acid or 2'-deoxymugineic acid, another metal chelator present in plants

Immediate, but Not Delayed, Microsurgical Skull Reconstruction Exacerbates Brain Damage in Experimental Traumatic Brain Injury Model

Moderate to severe traumatic brain injury (TBI) often results in malformations to the skull. Aesthetic surgical maneuvers may offer normalized skull structure, but inconsistent surgical closure of the skull area accompanies TBI. We examined whether wound closure by replacement of skull flap and bone wax would allow aesthetic reconstruction of the TBI-induced skull damage without causing any detrimental effects to the cortical tissue. Adult male Sprague-Dawley rats were subjected to TBI using the controlled cortical impact (CCI) injury model. Immediately after the TBI surgery, animals were randomly assigned to skull flap replacement with or without bone wax or no bone reconstruction, then were euthanized at five days post-TBI for pathological analyses. The skull reconstruction provided normalized gross bone architecture, but 2,3,5-triphenyltetrazolium chloride and hematoxylin and eosin staining results revealed larger cortical damage in these animals compared to those that underwent no surgical maneuver at all. Brain swelling accompanied TBI, especially the severe model, that could have relieved the intracranial pressure in those animals with no skull reconstruction. In contrast, the immediate skull reconstruction produced an upregulation of the edema marker aquaporin-4 staining, which likely prevented the therapeutic benefits of brain swelling and resulted in larger cortical infarcts. Interestingly, TBI animals introduced to a delay in skull reconstruction (i.e., 2 days post-TBI) showed significantly reduced edema and infarcts compared to those exposed to immediate skull reconstruction. That immediate, but not delayed, skull reconstruction may exacerbate TBI-induced cortical tissue damage warrants a careful consideration of aesthetic repair of the skull in TBI

The influence of speed and size on avian terrestrial locomotor biomechanics: predicting locomotion in extinct theropod dinosaurs

How extinct, non-avian theropod dinosaurs moved is a subject of considerable interest and controversy. A better understanding of non-avian theropod locomotion can be achieved by better understanding terrestrial locomotor biomechanics in their modern descendants, birds. Despite much research on the subject, avian terrestrial locomotion remains little explored in regards to how kinematic and kinetic factors vary together with speed and body size. Here, terrestrial locomotion was investigated in twelve species of ground-dwelling bird, spanning a 1,780-fold range in body mass, across almost their entire speed range. Particular attention was devoted to the ground reaction force (GRF), the force that the feet exert upon the ground. Comparable data for the only other extant obligate, striding biped, humans, were also collected and studied. In birds, all kinematic and kinetic parameters examined changed continuously with increasing speed, while in humans all but one of those same parameters changed abruptly at the walk-run transition. This result supports previous studies that show birds to have a highly continuous locomotor repertoire compared to humans, where discrete ‘walking’ and ‘running’ gaits are not easily distinguished based on kinematic patterns alone. The influences of speed and body size on kinematic and kinetic factors in birds are developed into a set of predictive relationships that may be applied to extinct, non-avian theropods. The resulting predictive model is able to explain 79–93% of the observed variation in kinematics and 69–83% of the observed variation in GRFs, and also performs well in extrapolation tests. However, this study also found that the location of the whole-body centre of mass may exert an important influence on the nature of the GRF, and hence some caution is warranted, in lieu of further investigation