Apyrase Functions in Plant Phosphate Nutrition and Mobilizes Phosphate from Extracellular ATP1

ATP, which is present in the extracellular matrix of multicellular organisms and in the extracellular fluid of unicellular organisms, has been shown to function as a signaling molecule in animals. The concentration of extracellular ATP (xATP) is known to be functionally modulated in part by ectoapyrases, membrane-associated proteins that cleave the γ- and β-phosphates on xATP. We present data showing a previously unreported (to our knowledge) linkage between apyrase and phosphate transport. An apyrase from pea (Pisum sativum) complements a yeast (Saccharomyces cerevisiae) phosphate-transport mutant and significantly increases the amount of phosphate taken up by transgenic plants overexpressing the gene. The transgenic plants show enhanced growth and augmented phosphate transport when the additional phosphate is supplied as inorganic phosphate or as ATP. When scavenging phosphate from xATP, apyrase mobilizes the γ-phosphate without promoting the transport of the purine or the ribose.

Biotechnology: Enhancing human nutrition in developing and developed worlds

While the last 50 years of agriculture have focused on meeting the food, feed, and fiber needs of humans, the challenges for the next 50 years go far beyond simply addressing the needs of an ever-growing global population. In addition to producing more food, agriculture will have to deal with declining resources like water and arable land, need to enhance nutrient density of crops, and achieve these and other goals in a way that does not degrade the environment. Biotechnology and other emerging life sciences technologies offer valuable tools to help meet these multidimensional challenges. This paper explores the possibilities afforded through biotechnology in providing improved agronomic “input” traits, differentiated crops that impart more desirable “output” traits, and using plants as green factories to fortify foods with valuable nutrients naturally rather than externally during food processing. The concept of leveraging agriculture as green factories is expected to have tremendous positive implications for harnessing solar energy to meet fiber and fuel needs as well. Widespread adaptation of biotech-derived products of agriculture should lay the foundation for transformation of our society from a production-driven system to a quality and utility-enhanced system.

Acclimation of Photosynthesis to Elevated CO2 under Low-Nitrogen Nutrition Is Affected by the Capacity for Assimilate Utilization. Perennial Ryegrass under Free-Air CO2 Enrichment1

Acclimation of photosynthesis to elevated CO2 has previously been shown to be more pronounced when N supply is poor. Is this a direct effect of N or an indirect effect of N by limiting the development of sinks for photoassimilate? This question was tested by growing a perennial ryegrass (Lolium perenne) in the field under elevated (60 Pa) and current (36 Pa) partial pressures of CO2 (pCO2) at low and high levels of N fertilization. Cutting of this herbage crop at 4- to 8-week intervals removed about 80% of the canopy, therefore decreasing the ratio of photosynthetic area to sinks for photoassimilate. Leaf photosynthesis, in vivo carboxylation capacity, carbohydrate, N, ribulose-1,5-bisphosphate carboxylase/oxygenase, sedoheptulose-1,7-bisphosphatase, and chloroplastic fructose-1,6-bisphosphatase levels were determined for mature lamina during two consecutive summers. Just before the cut, when the canopy was relatively large, growth at elevated pCO2 and low N resulted in significant decreases in carboxylation capacity and the amount of ribulose-1,5-bisphosphate carboxylase/oxygenase protein. In high N there were no significant decreases in carboxylation capacity or proteins, but chloroplastic fructose-1,6-bisphosphatase protein levels increased significantly. Elevated pCO2 resulted in a marked and significant increase in leaf carbohydrate content at low N, but had no effect at high N. This acclimation at low N was absent after the harvest, when the canopy size was small. These results suggest that acclimation under low N is caused by limitation of sink development rather than being a direct effect of N supply on photosynthesis.

Food, nutrition and public health in contemporary Spain, 1900-1936

Within the context of the health reforms introduced in Spain in the early 20th century and the influence of international health organisations on their development, this article analyses the growing interest that surrounded nourishment and food-related problems at that time in relation to healthcare, the diagnosis provided by hygienists of such problems, and the public health measures applied to resolve them. The issue of hygienic diet and the collective aspect of nutritional problems became priorities in the field of healthcare. Two of the most prominent initiatives involved setting up a Department of Nutrition and Food Hygiene and Bromatological Technique during the early years of the Second Republic, as part of the National School of Health, as well as a Food Hygiene Service. Spanish hygienists underlined the importance of education and the dissemination of information about food hygiene, health and nutrition, in order to overcome the qualitative and quantitative deficiencies observed in the average diet of the Spanish population.

Effect of commercial amino acids on iron nutrition of tomato plants grown under lime-induced iron deficiency

The objective of this work was to study the effect of root and foliar application of two commercial products containing amino acids from plant and animal origin on iron (Fe) nutrition of tomato seedlings cultivated in two nutrient media: lime and normal nutrient solutions. In the foliar-application experiment, each product was sprayed with 0.5 and 0.7 mL L–1 2, 7, 12, and 17 d after transplanting. In the root application experiment, 0.1 and 0.2 mL L–1 of amino acids products were added to the nutrient solutions. In both experiments, untreated control plants were included as well. Foliar and root application of the product containing amino acids from animal origin caused severe plant-growth depression and nonpositive effects on Fe nutrition were found. In contrast, the application of the product from plant origin stimulated plant growth. Furthermore, significantly enhanced root and leaf FeIII-chelate reductase activity, chlorophyll concentration, leaf Fe concentration, and FeII : Fe ratio were found in tomato seedlings treated with the product from plant origin, especially when the amino acids were directly applied to the roots. These effects were more evident in plants developed under lime-induced Fe deficiency. The positive results on Fe uptake may be related to the action of glutamic acid, the most abundant amino acid in the formulation of the product from plant origin.