Phosphorus‐deficiency effects on response of symbiotic N2 fixation and carbohydrate status in soybean to atmospheric CO2 enrichment

The impact of phosphorus (P) deficiency on response of symbiotic N₂ fixation and carbohydrate accumulation in soybean (Glycine max [L.] Merr.) to atmospheric CO₂ enrichment was examined. Plants inoculated with Bradyrhizobium japonicum MN 110 were grown in growth chambers with controlled atmospheres of 400 and 800 μL CO₂ L^‐1 and supplied either 1.0 mM‐P (P‐sufficient) or 0.05 mM‐P (P‐deficient) nitrogen (N)‐free nutrient solution. When plants were supplied with sufficient P, CO₂ enrichment significantly increased whole plant dry mass (83%), nodule mass (67%), total nitrogenase activity (58%), and N (35%) and P (47%) accumulation at 35 days after transplanting (DAT). Under sufficient P supply, CO₂ enrichment significantly increased starch concentrations in nodules compared to the normal atmospheric CO₂ treatment. Under normal CO₂ levels (400 μL L^‐1) nonstructural carbohydrate concentration (starch plus soluble sugar) was significantly higher in leaves of P‐deficient plants than in leaves of P‐sufficient plants in which nonstructural carbohydrate concentration exhibited a strong diurnal pattern. Under deficient P supply whole plant dry mass, symbiotic N₂‐fixation parameters, and N and P accumulation were not enhanced by atmospheric CO₂ enrichment. Phosphorus deficiency decreased nonstructural carbohydrate accumulation in nodules at the end of a 10‐day period in which functional activity was developing by 86% relative to P‐sufficient controls. While P deficiency elicited significant increases in the nonstructural carbohydrate concentration in leaves, it caused significant decreases in the nonstructural carbohydrate concentration in nodules over the diurnal cycle from 30 to 31 DAT. Collectively, these results indicate that the lack of a symbiotic N₂‐fixation response to atmospheric CO₂ enrichment by P‐deficient plants may be related to the decreased carbohydrate status of nodules.     

Hydrogen and aluminum inhibition of soybean root extension from limed soil into acid subsurface solutions

Soybean [Glycine max (L.) Merr. cv. ‘Ransom'] root elongation under varying concentrations of solution hydrogen (H) and aluminum (Al) was investigated in a vertical split‐root system. Roots extending from a limed and fertilized soil compartment grew for 12 days into a subsurface compartment with solutions adjusted to either different pH values from 3.7 to 5.5 or a factorial combination of pH (4.0,4.6, and 5.2) and Al (0,7.5, 15, and 30 μM) levels. Ionic forms of Al were estimated with GEOCHEM and solution Al was determined with ferron. Boron (B) (18.5 μM) and zinc (Zn) (0.5 μM) were supplied to all solution treatments, in addition to 2000 μM Ca, after preliminary studies at pH 5.2 without Al indicated that their omission inhibited length of tap roots and their laterals in the subsurface compartment. Both H⁺ and Al inhibited the length of lateral roots more than tap roots. Lateral roots failed to develop on tap roots at pH<4.3 or in treatments with 30 μM Al. Relative tap root length (RRL) among treatments receiving Al correlated with Al as measured by reaction with ferron for 30s. Ferron‐reactive Al was correlated to GEOCHEM‐predicted Al³⁺ activity (r=0.99). A 50% reduction in RRL occurred with either 2.1 μM Al³⁺ activity or 4.9 uM ferron‐reactive Al. The absence of shoot and soil‐root biomass differences among solution treatments in the split‐root system indicated that differences in root growth in the subsurface compartment were not directly confounded with differences in top growth.     

Calcium alleviation of hydrogen and aluminum inhibition of soybean root extension from limed soil into acid subsurface solutions

Alleviation by calcium (Ca) of inhibition of soybean [Glycine max (L.) Merr. cv. ‘Ransom'] root elongation by hydrogen (H) and aluminum (Al) was evaluated in a vertical split‐root system. Roots extending from a limed and fertilized soil compartment grew for 12 days into a subsurface compartment containing nutrient solution with treatments consisting of factorial combinations of either pH (4.0, 4.6, and 5.5) and Ca (0.2, 2.0, 10, and 20 mM), Al (7.5, 15, and 30 μM) and Ca (2.0,10, and 20 mM) at pH 4.6, or Ca (2, 7, and 12 mM) levels and counter ions (SO₄ and Cl) at pH 4.6 and 15 μM Al. Length of tap roots and their laterals increased with solution Ca concentration and pH value, but decreased with increasing Al level. Length of both tap and lateral roots were greater when Ca was supplied as CaSO₄ than as CaCl₂, but increasing Ca concentration from 2 to 12 mM had a greater effect on alleviating Al toxicity than Ca source. In the absence of Al, relative root length (RRL) of tap and lateral roots among pH and Ca treatments was related to the Ca:H molar activity ratio of solutions (R²≥0.82). Tap and lateral RRL among solutions with variable concentrations of Al and Ca at pH 4.6 were related to both the sum of the predicted activities of monomeric Al (R²≥0.92) and a log‐transformed and valence‐weighted balance between activities of Ca and selected monomeric Al species (R²≥0.95). In solutions with 15 μM Al at pH 4.6, response of tap and lateral RRL to variable concentrations of CaSO₄ and CaCl₂ were related to predicted molar activity ratios of both Ca:Al³⁺ (R²≥0.89) and Ca:3 monomeric Al (R²≥0.90), provided that AISO₄ and AI(SO₄)₂ species were excluded from the latter index. In all experiments H and Al inhibited length of lateral roots more than tap roots, and a greater Ca:H or Ca:Al concentration ratio was required in solutions to achieve similar RRL values as tap roots.     

Tools for studying dry-cured ham processing by using computed tomography

An accurate knowledge and optimization of dry-cured ham elaboration processes could help to reduce operating costs and maximize product quality. The development of nondestructive tools to characterize chemical parameters such as salt and water contents and a(w) during processing is of special interest. In this paper, predictive models for salt content (R(2) = 0.960 and RMSECV = 0.393), water content (R(2) = 0.912 and RMSECV = 1.751), and a(w) (R(2) = 0.906 and RMSECV = 0.008), which comprise the whole elaboration process, were developed. These predictive models were used to develop analytical tools such as distribution diagrams, line profiles, and regions of interest (ROIs) from the acquired computed tomography (CT) scans. These CT analytical tools provided quantitative information on salt, water, and a(w) in terms of content but also distribution throughout the process. The information obtained was applied to two industrial case studies. The main drawback of the predictive models and CT analytical tools is the disturbance that fat produces in water content and a(w) predictions.     

Who Complains About Alligators? Cognitive and Situational Factors Influence Behavior Toward Wildlife

Understanding perceptual and situational factors underlying nuisance complaints can help managers maintain carnivore populations while mitigating conflicts with people. Our study uses data from a mail survey (n = 467 complainants about nuisance alligators, and n = 669 random Florida residents) and a three-step binary logistic regression analysis to examine how general attitudes, specific beliefs, and situational factors influence the behavior of reporting nuisance alligators. Residence adjacent to fresh water, the presence of outdoor pets, higher risk belief scores, higher nuisance belief scores, higher education, and older age were all related to complaining about an alligator, whereas general attitude toward alligators was not. Results are consistent with the “specificity principle” for attitude–behavior correspondence and emphasize the importance of situational factors as behavioral determinants. Targeted harvest areas can help to manage complaints in marginal habitats where risk from alligators is persistent. Information about protective behaviors and benefits of alligators can motivate residents to avoid dangerous encounters.     

Geostatistical modelling and mapping of nematode-based soil ecological quality indices in a polluted nature reserve

Nematodes are indicators of soil quality and soil health. Knowledge of the relationships between nematode-based soil quality indices and environmental properties is beneficial for assessing environmental threats on soil biota. This study evaluated the spatial distribution of nematode-based soil quality indices in a 23-ha heavy metal-polluted nature reserve using geostatistical methods. We expected that a selection of abiotic soil properties (pH and moisture, clay, organic matter, cadmium (Cd), and zinc (Zn) contents) could explain a significant portion of the spatial variation of the indices and that regression kriging could more accurately model their spatial distribution than ordinary kriging. A stratified simple random sampling scheme was used to select 80 locations where soil samples were taken to extract nematodes and derive the indices. The area had a distinct gradient in soil properties with Cd and Zn content ranging from 0.07 to 68.9 and 5.3 to 1329 mg kg^-1, respectively. Linear regression models were fitted to describe the relationships between the indices and soil properties. By also modelling the spatial correlation structure of regression residuals using spherical semivariograms, regression kriging was used to produce maps of the indices. The regression models explained between 21% and 44% of the total original variance in the indices. Soil pH was a significant explanatory variable in almost all cases, while heavy metal conent had a remarkably low effect. In some cases, the regression residuals had spatial structure. Independent validation indicated that in all cases, regression kriging performed slightly better because of having lower values of the root mean square prediction error and a mean prediction error closer to zero than ordinary kriging. This study showed the importance of soil properties in explaining the spatial distribution of biological soil quality indices in ecological risk assessment.     

Transient co-expression with three <Emphasis Type="Italic">O</Emphasis>-glycosylation enzymes allows production of GalNAc-<Emphasis Type="Italic">O</Emphasis>-glycosylated Granulocyte-Colony Stimulating Factor in <Emphasis Type="Italic">N. benthamiana</Emphasis>

Background

Expression of economically relevant proteins in alternative expression platforms, especially plant expression platforms, has gained significant interest in recent years. A special interest in working with plants as bioreactors for the production of pharmaceutical proteins is related to low production costs, product safety and quality. Among the different properties that plants can also offer for the production of recombinant proteins, protein glycosylation is crucial since it may have an impact on pharmaceutical functionality and/or stability.

Results

The pharmaceutical glycoprotein human Granulocyte-Colony Stimulating Factor was transiently expressed in Nicotiana benthamiana plants and subjected to mammalian-specific mucin-type O-glycosylation by co-expressing the pharmaceutical protein together with the glycosylation machinery responsible for such post-translational modification.

Conclusions

The pharmaceutical glycoprotein human Granulocyte-Colony Stimulating Factor can be expressed in N. benthamiana plants via agroinfiltration with its native mammalian-specific mucin-type O-glycosylation.

     

1-MCP处理提高不同成熟度Spadona梨贮后品质的研究

Spadona梨是一种不需要低温诱导乙烯生成的热带水果。本研究采用乙烯抑制剂1-甲基环丙烯（1-MCP）对不同成熟阶段的梨果实进行处理,以期进一步了解其成熟过程中乙烯的作用,同时提高梨果实贮藏后的品质。