Search

The term Spondyloptosis is used to describe a grade V spondylolisthesis, being a subluxation bigger than l00%. The trauma spondyloptosis binding L5-S1 is reported the most prevalent. It is rare in the cephalad lumbar segment to the lumbosacral junction. Two cases of spondyloptosis of L4-L5 have been reported until August 2010, caused by high energy trauma, both with the L4 vertebral body presented an anterior displacement of the vertebral body of L5. We report a patient with traumatic spondyloptosis of L4-L5 caused by a high-energy mechanism. The mechanism of injury and surgical management are described and the clinical evaluation is performed with a minimum follow-up of 8 months. [ABSTRACT FROM AUTHOR]

•The effects of zinc (Zn) toxicity on photosynthesis and respiration were investigated in sugar beet ( Beta vulgaris) plants grown hydroponically with 1.2, 100 and 300 μM Zn. •A photosynthesis limitation analysis was used to assess the stomatal, mesophyll, photochemical and biochemical contributions to the reduced photosynthesis observed under Zn toxicity. •The main limitation to photosynthesis was attributable to stomata, with stomatal conductances decreasing by 76% under Zn excess and stomata being unable to respond to physiological and chemical stimuli. The effects of excess Zn on photochemistry were minor. Scanning electron microscopy showed morphological changes in stomata and mesophyll tissue. Stomatal size and density were smaller, and stomatal slits were sealed in plants grown under high Zn. Moreover, the mesophyll conductance to CO2 decreased by 48% under Zn excess, despite a marked increase in carbonic anhydrase activity. Respiration, including that through both cytochrome and alternative pathways, was doubled by high Zn. •It can be concluded that, in sugar beet plants grown in the presence of excess Zn, photosynthesis is impaired due to a depletion of CO2 at the Rubisco carboxylation site, as a consequence of major decreases in stomatal and mesophyll conductances to CO2. [ABSTRACT FROM AUTHOR]

The most commonly used and efficient compound for iron (Fe)-fertilisation of fruit crops grown in calcareous soils is the synthetic Fe(III)-chelate of ethylenediamine-N,N-di-(ortho-hydroxyphenyl) acetic acid, usually known as Fe(III)-o,o-EDDHA. However, the mechanism(s) of plant Fe uptake from this compound, and the environmental implications of its use, are still not completely understood. This lack of information is due, in part, to the lack of suitable analytical methods capable of determining the very low concentrations of this Fe(III)-chelate which may occur in complex matrices such as plant tissues and fluids after Fe-fertilisation. In this report, the main issues for studies on the biological and environmental implications of fertilisation with synthetic Fe(III)-chelates are discussed, focussing on new possibilities offered by recently developed analytical technologies. [ABSTRACT FROM AUTHOR]

Effects of 10 μM cadmium (supplied as Cd nitrate) on the utilization and allocation of iron (Fe) were investigated in poplar (Populus alba L.) plants grown in nutrient solution with Fe(III)-EDTA or Fe(III)-citrate as the Fe source. The effects of Cd were also compared with those of Fe deprivation. The accumulation of Fe in roots was 10-fold higher in plants grown with Fe-citrate than with Fe-EDTA. Cadmium decreased leaf chlorophyll concentrations and photosynthetic rates, and these decreases were more marked in plants grown with Fe-citrate than with Fe-EDTA. In both Fe treatments, addition of Cd caused large increases in root and shoot apoplasmic and non-apoplasmic Cd contents and increases in root Fe content; however, Cd decreased shoot Fe content, especially in plants grown with Fe-citrate. New leaves of plants grown with Fe-citrate had small cellular (non-apoplasmic) Fe pools, whereas these pools were large in new leaves of plants grown with Fe-EDTA. Non-apoplasmic Cd pools in new leaves were smaller in plants grown with Fe-citrate than with Fe-EDTA, indicating that inactivation of non-apoplasmic Cd pools is facilitated more by Fe-EDTA than by Fe-citrate. In the presence of Cd, Fe-EDTA was also superior to Fe-citrate in maintaining an adequate Fe supply to poplar shoots. Differences in plant responses to Fe-EDTA and Fe-citrate may reflect differences in long-distance transport of Fe rather than in acquisition of Fe by roots. [ABSTRACT FROM AUTHOR]

A comparative study of two kiwifruit genotypes (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson var. deliciosa) with different tolerance to iron (Fe) deficiency was conducted to identify biochemical features associated with tolerance to Fe deficiency. After 14 days of growth in hydroponic culture under Fe-deficient and Fe-sufficient conditions, leaf chlorophyll concentration, activities of ferric chelate reductase (FCR), phosphoenolpyruvate carboxylase (PEPC) and citrate synthase in root extracts, concentrations of organic acids in roots, leaves and xylem sap, and xylem sap pH were measured. In response to Fe deficiency, the tolerant genotype D1 showed: (i) higher FCR activity associated with a longer lasting induction of FCR; (ii) higher PEPC activity; (iii) higher concentrations of citric acid in roots; and (iv) lower xylem sap pH compared with the susceptible genotype Hayward. These findings imply that induction of FCR and PEPC activities in roots in response to Fe deficiency are important physiological adaptations enabling Fe-efficient kiwifruit plants to tolerate Fe deficiency. [ABSTRACT FROM PUBLISHER]

In this work we characterize the changes induced by iron deficiency in the pigment composition of pear (Pyrus communis L.) leaves grown under high light intensities in field conditions in Spain. Iron deficiency induced decreases in neoxanthin and β-carotene concomitantly with decreases in chlorophyll a, whereas lutein and carotenoids within the xanthophyll cycle were less affected. Iron deficiency caused major increases in the lutein/chlorophyll a and xanthophyll cycle pigments/chlorophyll a molar ratios. The chlorophyll a/chlorophyll b ratio increased in response to iron deficiency. The carotenoids within the xanthophyll cycle in iron-deficient and in iron-sufficient (control) leaves underwent epoxidations and de-epoxidations in response to ambient light conditions. In control leaves dark-adapted for several hours, most of the xanthophyll cycle pigment pool was in the epoxidated form violaxanthin, whereas iron-deficient leaves had significant amounts of zeaxanthin. Iron-deficient leaves also exhibited an increased non-photochemical quenching, supporting the possibility of a role for pigments within the xanthophyll cycle in photoprotection. [ABSTRACT FROM AUTHOR]

Abstract Background Plants grown under iron deficiency show different morphological, biochemical and physiological changes. These changes include, among others, the elicitation of different strategies to improve the acquisition of Fe from the rhizosphere, the adjustment of Fe homeostasis processes and a reorganization of carbohydrate metabolism. The application of modern techniques that allow the simultaneous and untargeted analysis of multiple proteins and metabolites can provide insight into multiple processes taking place in plants under Fe deficiency. The objective of this study was to characterize the changes induced in the root tip proteome and metabolome of sugar beet plants in response to Fe deficiency and resupply. Results Root tip extract proteome maps were obtained by 2-D isoelectric focusing polyacrylamide gel electrophoresis, and approximately 140 spots were detected. Iron deficiency resulted in changes in the relative amounts of 61 polypeptides, and 22 of them were identified by mass spectrometry (MS). Metabolites in root tip extracts were analyzed by gas chromatography-MS, and more than 300 metabolites were resolved. Out of 77 identified metabolites, 26 changed significantly with Fe deficiency. Iron deficiency induced increases in the relative amounts of proteins and metabolites associated to glycolysis, tri-carboxylic acid cycle and anaerobic respiration, confirming previous studies. Furthermore, a protein not present in Fe-sufficient roots, dimethyl-8-ribityllumazine (DMRL) synthase, was present in high amounts in root tips from Fe-deficient sugar beet plants and gene transcript levels were higher in Fe-deficient root tips. Also, a marked increase in the relative amounts of the raffinose family of oligosaccharides (RFOs) was observed in Fe-deficient plants, and a further increase in these compounds occurred upon short term Fe resupply. Conclusions The increases in DMRL synthase and in RFO sugars were the major changes induced by Fe deficiency and resupply in root tips of sugar beet plants. Flavin synthesis could be involved in Fe uptake, whereas RFO sugars could be involved in the alleviation of oxidative stress, C trafficking or cell signalling. Our data also confirm the increase in proteins and metabolites related to carbohydrate metabolism and TCA cycle pathways.

This study presents information on the dynamics of sugar beet (Beta vulgaris L.) root metabolic responses to Fe deficiency. Four days after Fe withdrawal from the nutrient solution, the concentration of reduced glutathione (GSH) and the activities of ferric chelate reductase (FC-R, E.C. 1.6.99.13) and ascorbate peroxidase (APX, E.C. 1.11.1.11) showed marked differences with the control values. The differences in root fresh weight, the concentrations of ascorbate (Asc) and soluble proteins, and proton release rates by roots became more prominent after the first week. Time course kinetics of FC-R activity and proton extrusion showed induction maxima, followed by rapid declines with the progress of Fe deficiency. The time courses of root Asc and GSH concentrations showed gradual increases with the advancement of Fe deficiency suggesting that plant responses to Fe deficiency stress may include a shift in the redox balance inside the root cells towards more reduced state. Data imply that an alternative Asc-dependent Fe reduction may become important with the advancement of Fe deficiency stress, when FC-R activity is declining. The time course of APX activity reveals that it could be a sensitive indicator of the initial changes in the plant Fe nutritional status. [Copyright &y& Elsevier]