Fructan synthesis is inhibited by phosphate in warm-grown, but not in cold-treated,excised barley leaves.

The inhibition by phosphate of fructan accumulation has been investigated in warm3 grown and cold-treated barley (Hordeum vulgare L.) plants. • Detached leaves were incubated in water or phosphate for 24 h under lighting or in darkness. Fructosyltransferase, sucrose phosphate synthase (SPS) and cytosolic fructose- 1, 6 - bisphosphatase (FBPase) activities were subsequently analysed, as well as the content of carbohydrates, hexose-phosphates, phosphate, amino acids and protein. • In warm-grown leaves, phosphate decreased fructan accumulation and total carbon in carbohydrates and did not affect protein contents. Phosphate increased hexose phosphates, phosphate and amino acids. Fructosyltransferase and FBPase activities were not affected by phosphate feeding, while SPS activity was inhibited by phosphate in incubations both in light and in darkness. In cold-treated leaves, which prior to incubation had higher SPS activities than warm-grown leaves, phosphate had no inhibitory effect on fructan accumulation, carbohydrate content or total carbon in carbohydrates. SPS and FBPase activities were unaffected by phosphate. • The results indicate that phosphate decreases fructan accumulation through an inhibition of SPS whenever this activity is not high prior to a rise in phosphate content.R. M. had a Ramón y Cajal research contract, and S.K. was the recipient of a grant for stays of foreign researchers in Spain, both from the Ministry of Education, Science and Sport. This work has been funded by the Junta de Castilla y León (Project CSI19/03).Peer reviewe

Vascular Endothelial Growth Factor (VEGF) Prevents the Downregulation of the Cholinergic Phenotype in Axotomized Motoneurons of the Adult Rat

Vascular endothelial growth factor (VEGF) was initially characterized by its activity on the vascular system. However, there is growing evidence indicating that VEGF also acts as a neuroprotective factor, and that its administration to neurons suffering from trauma or disease is able to rescue them from cell death. We questioned whether VEGF could also maintain damaged neurons in a neurotransmissive mode by evaluating the synthesis of their neurotransmitter, and whether its action would be direct or through its well-known angiogenic activity. Adult rat extraocular motoneurons were chosen as the experimental model. Lesion was performed by monocular enucleation and immediately a gelatine sponge soaked in VEGF was implanted intraorbitally. After 7 days, abducens, trochlear, and oculomotor nuclei were examined by immunohistochemistry against choline acetyltransferase (ChAT), the biosynthetic enzyme of the motoneuronal neurotransmitter acetylcholine. Lesioned motoneurons exhibited a noticeable ChAT downregulation which was prevented by VEGF administration. To explore whether this action was mediated via an increase in blood vessels or in their permeability, we performed immunohistochemistry against laminin, glucose transporter-1 and the plasmatic protein albumin. The quantification of the immunolabeling intensity against these three proteins showed no significant differences between VEGF-treated, axotomized and control animals. Therefore, the present data indicate that VEGF is able to sustain the cholinergic phenotype in damaged motoneurons, which is a first step for adequate neuromuscular neurotransmission, and that this action seems to be mediated directly on neurons since no sign of angiogenic activity was evident. These data reinforces the therapeutical potential of VEGF in motoneuronal diseases.España, MINECO and FEDER BFU2015-64515-PJunta de Andalucía and FEDER : P10-CVI605

Diurnal changes of Rubisco in response to elevated CO2, temperature and nitrogen in wheat grown under temperature gradient tunnels.

Growth at elevated CO2 and temperature often leads to decreased Rubisco activity. We investigated the effects of increased CO2, temperature and nitrogen on the diurnal changes in the control of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco) activity in wheat (Triticum aestivum L.). Spring wheat was grown at ambient and 700 μmol mol-1 CO2, under ambient and 4 ºC warmer temperatures, and with two levels of nitrogen supply in field tunnels in a Mediterranean environment. At ear emergence, elevated CO2 increased Rubisco activation, but decreased Rubisco protein and, with high nitrogen, Rubisco specific activity, and had no effect on the rbcS transcript. Warmer temperatures tended to decrease the rbcS mRNA level and Rubisco protein, although the effect on Rubisco activity was small. High nitrogen decreased Rubisco activation or specific activity, depending on the CO2 concentration. It increased Rubisco protein at the end of the night, but accelerated its diurnal loss. The main changes after anthesis were the disappearance of the decrease in Rubisco specific activity caused by elevated CO2, an increase in this activity with above-ambient temperatures combined with high nitrogen, and that high temperature and nitrogen did not affect Rubisco protein contents. This study suggests that decreased leaf protein and increased levels of a Rubisco inhibitor, rather than gene repression by sugars, are involved in acclimation to elevated CO2. High nitrogen increases this down regulation. Changes during growth in levels of leaf metabolites and protein may alter the relative importance of levels of inhibitors and Rubisco amounts for Rubisco regulation.The technical cooperation of Libia Hernandez and Angel Verdejo is acknowledged. The staff of the IRNASA experimental farm helped with crop sowing and fertilizer application. The Northern blots analyses were made at the laboratory of Prof. M. Stitt (Botanical Institute, University of Heidelberg, Germany) with Marina Bueno CSIC-DFG funds granted to R. Morcuende. This work was funded by the Spanish Plan Nacional de Investigación y Desarrollo (grant no. CLI96-0396). We thank Dr. Christine Raines (Dept. of Biological Sciences, John Tabor Laboratories, University of Essex, UK) for the generous gift of the Rubisco cDNA.Peer reviewe

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Acclimatory responses of stomatal conductance and photosynthesis to elevated CO2 and temperature in wheat crops grown at varying levels of N supply, in a Mediterranean environment.

The short and long-term responses of flag leaf stomatal conductance (gs) and rate of photosynthesis (An) to elevated CO2 (757 μmol mol-1), 4 ºC warmer temperatures and N supply were investigated in spring wheat (Triticum aestivum L. cv. Alcalá) crops grown in two seasons in field conditions under temperature gradient tunnels, in a Mediterranean environment. Plants grown at elevated CO2 had lower gs and An measured at 700 μmol mol-1 CO2 than ambient CO2-grown plants, indicating acclimatory responses to elevated CO2. N supply, which was lower in 2003 than 2002, reduced this acclimation in both years. Warmer temperatures at high nitrogen supply also decreased An acclimation. Acclimatory responses of An and gs were highly correlated. The analysis of the gs – An relationship indicated that both parameters are probably linked and respond in parallel to elevated CO2 at ambient temperatures, but non-parallel responses were observed at above-ambient temperatures.This work was funded by the Spanish Programme of Research and Development (grant No. BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements and chlorophyll determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Quantitative RT-PCR Platform for Transcript Profiling of C-N Metabolism Related Genes in Durum Wheat: Study under a Future Climate Change Scenario

4 figuras. -- Póster presentado en el congreso: BIT's 6th Annual World Congress of Molecular & Cell Biology 2016. Theme: Unlocking the Secrets of Cells. Dalian (China), 25-28 de abril de 2016.Climate change is a major challenge to global food supply, thus is important understanding the mechanisms of crop responses to future environmental conditions. To achieve this goal, we developed a qRT-PCR platform for the expression analysis of more than a hundred C and N metabolism genes in durum wheat, based on available bread wheat genes and the identification of orthologs of known genes in other species. Additionally, we investigated the effect of elevated CO2 and temperature on primary metabolism of durum wheat grown in field chambers at two levels of N supply by combining transcript level analysis, using the qRT-PCR platform, with biochemical and physiological parameters in flag leaves at anthesis.This work was supported by the Spanish National R&D&i Plan of the Ministry of Economy and Competitiveness (grants AGL2006-13541-C02-02, AGL2009-11987 and BES-2010-031029 to R.V.).N

Particle Swarm Optimisation Prediction Model for Surface Roughness

Acrylic sheet is a crystal clear (with transparency equal to optical glass), lightweight material having outstanding weather ability, high impact resistance, good chemical resistance, and excellent thermo-formability and machinability. This paper develops the artificial intelligent model using partial swarm optimization (PSO) to predict the optimum surface roughness when cutting acrylic sheets with laser beam cutting (LBC). Response surface method (RSM) was used to minimize the number of experiments. The effect of cutting speed, material thickness, gap of tip and power towards surface roughness were investigated. It was found that the surface roughness is significantly affected by the tip distance followed by the power requirement, cutting speed and material thickness. Surface roughness becomes larger when using low power, tip distance and material thickness. Combination of low cutting speed, high power, tip distance and material distance produce fine surface roughness. Some defects were found in microstructure such as burning, melting and wavy surface. The optimized parameters by PSO are cutting speed (2600 pulse/s), tip distance (9.70 mm), power (95%) and material thickness (9 mm) which produce roughness around 0.0129 µm

Gas exchange acclimation to elevated CO2 in upper-sunlit and lower-shaded canopy leaves in relation to nitrogen acquisition and partitioning in wheat grown in field chambers.

Growth at elevated CO2 often decreases photosynthetic capacity (acclimation) and leaf N concentrations. Lower-shaded canopy leaves may undergo both CO2 and shade acclimation. The relationship of acclimatory responses of flag and lower-shaded canopy leaves of wheat (Triticum aestivum L.) to the N content, and possible factors affecting N gain and distribution within the plant were investigated in a wheat crop growing in field chambers set at ambient (360 μmol mol-1) and elevated (700 μmol mol-1) CO2, and with two amounts of N fertilizer (none and 70 kg ha-1 applied on 30 April). Photosynthesis, stomatal conductance and transpiration at a common measurement CO2, chlorophyll and Rubisco levels of upper-sunlit (flag) and lower-shaded canopy leaves were significantly lower in elevated relative to ambient CO2-grown plants. Both whole shoot N and leaf N per unit area decreased at elevated CO2, and leaf N declined with canopy position. Acclimatory responses to elevated CO2 were enhanced in N-deficient plants. With N supply, the acclimatory responses were less pronounced in lower canopy leaves relative to the flag leaf. Additional N did not increase the fraction of shoot N allocated to the flag and penultimate leaves. The decrease in photosynthetic capacity in both upper-sunlit and lower-shaded leaves in elevated CO2 was associated with a decrease in N contents in above-ground organs and with lower N partitioning to leaves. A single relationship of N per unit leaf area to the transpiration rate accounted for a significant fraction of the variation among sun-lit and shaded leaves, growth CO2 level and N supply. We conclude that reduced stomatal conductance and transpiration can decrease plant N, leading to acclimation to CO2 enrichment.This work was funded by the Spanish ‘Plan Nacional de Investigación y Desarrollo’ (grant N° BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements, chlorophyll and Rubisco activity determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe

Putrescine: A Key Metabolite Involved in Plant Development, Tolerance and Resistance Responses to Stress

Putrescine (Put) is the starting point of the polyamines (PAs) pathway and the most common PA in higher plants. It is synthesized by two main pathways (from ornithine and arginine), but recently a third pathway from citrulline was reported in sesame plants. There is strong evidence that Put may play a crucial role not only in plant growth and development but also in the tolerance responses to the major stresses affecting crop production. The main strategies to investigate the involvement of PA in plant systems are based on the application of competitive inhibitors, exogenous PAs treatments, and the most efficient approaches based on mutant and transgenic plants. Thus, in this article, the recent advances in understanding the role of this metabolite in plant growth promotion and protection against abiotic and biotic stresses will be discussed to provide an overview for future research

Gas exchange acclimation to elevated CO2 in upper-sunlit and lower-shaded canopy leaves in relation to nitrogen acquisition and partitioning in wheat grown in field chambers.

Growth at elevated CO2 often decreases photosynthetic capacity (acclimation) and leaf N concentrations. Lower-shaded canopy leaves may undergo both CO2 and shade acclimation. The relationship of acclimatory responses of flag and lower-shaded canopy leaves of wheat (Triticum aestivum L.) to the N content, and possible factors affecting N gain and distribution within the plant were investigated in a wheat crop growing in field chambers set at ambient (360 μmol mol-1) and elevated (700 μmol mol-1) CO2, and with two amounts of N fertilizer (none and 70 kg ha-1 applied on 30 April). Photosynthesis, stomatal conductance and transpiration at a common measurement CO2, chlorophyll and Rubisco levels of upper-sunlit (flag) and lower-shaded canopy leaves were significantly lower in elevated relative to ambient CO2-grown plants. Both whole shoot N and leaf N per unit area decreased at elevated CO2, and leaf N declined with canopy position. Acclimatory responses to elevated CO2 were enhanced in N-deficient plants. With N supply, the acclimatory responses were less pronounced in lower canopy leaves relative to the flag leaf. Additional N did not increase the fraction of shoot N allocated to the flag and penultimate leaves. The decrease in photosynthetic capacity in both upper-sunlit and lower-shaded leaves in elevated CO2 was associated with a decrease in N contents in above-ground organs and with lower N partitioning to leaves. A single relationship of N per unit leaf area to the transpiration rate accounted for a significant fraction of the variation among sun-lit and shaded leaves, growth CO2 level and N supply. We conclude that reduced stomatal conductance and transpiration can decrease plant N, leading to acclimation to CO2 enrichment.This work was funded by the Spanish ‘Plan Nacional de Investigación y Desarrollo’ (grant N° BFI2000-0871). A. Del Pozo was the recipient of a fellowship from the Spanish Ministry of Education for a sabbatical leave. R. Morcuende had a Ramón y Cajal research contract from the Spanish Ministry of Education. The technical cooperation of A.L. Verdejo in gas exchange measurements, chlorophyll and Rubisco activity determination is acknowledged. We thank the staff of the experimental farm of IRNASA for assistance in crop husbandry.Peer reviewe