Phosphorous forms in cultivated indian black earth (anthrosols) of varying texture in the brazilian Amazon

Despite the agricultural importance of Indian Black Earth (IBE) in the Amazon region, there are few studies that report on the relation between soil texture and chemical fertility of IBE. These soils of pre-Colombian origin, with high contents of P, Ca and other nutrients are found across the Amazon valley. IBE profiles were studied to evaluate the total contents of P, its primary chemical forms and the P transformation phases in areas with IBE soils of variable texture and in adjacent reference soils. The soil texture strongly influenced soil fertility, changing in terms of transformation of the primary P forms and, consequently, predominant P forms in IBE. Soils with texture varying between clay and heavy clay had higher total P contents and primary Ca-P forms. Highest P-Al and lowest total P amounts were observed at the site Rio Preto da Eva, where texture varies from sandy loam to sandy clay loam. In the IBE with clay texture the amounts of soluble P, extracted with NH4Cl were highest, although different from Mehlich 1-extractable amounts.

Expression analyses of three members of the AtPHO1 family reveal differential interactions between signaling pathways involved in phosphate deficiency and the responses to auxin, cytokinin, and abscisic acid.

The PHO1 protein is involved in loading inorganic phosphate (Pi) to the root xylem. Ten genes homologous to AtPHO1 are present in the Arabidopsis thaliana (L.) Heyn genome. From this gene family, transcript levels of only AtPHO1, AtPHO1;H1 and AtPHO1;H10 were increased by Pi-deficiency. While the up-regulation of AtPHO1;H1 and AtPHO1;H10 by Pi deficiency followed the same rapid kinetics and was dependent on the PHR1 transcription factor, phosphite only strongly suppressed the expression of AtPHO1;H1 and had a minor effect on AtPHO1;H10. Addition of sucrose was found to increase transcript levels of both AtPHO1 and AtPHO1;H1 in Pi-sufficient or Pi-deficient plants, but to suppress AtPHO1:H10 under the same conditions. Treatments of plants with auxin or cytokinin had contrasting effect depending on the gene and on the Pi status of the plants. Thus, while both hormones down-regulated expression of AtPHO1 independently of the plant Pi status, auxin and cytokinin up-regulated AtPHO1;H1 and AtPHO1;H10 expression in Pi-sufficient plants and down-regulated expression in Pi-deficient plants. Treatments with abscisic acid inhibited AtPHO1 and AtPHO1;H1 expression in both Pi-sufficient and Pi-deficient plants, but increased AtPHO1;H10 expression under the same conditions. The inhibition of expression by abscisic acid of AtPHO1 and AtPHO1;H1, and of the Pi-starvation responsive genes AtPHT1;1 and AtIPS1, was dependant on the ABI1 type 2C protein phosphatase. These results reveal that various levels of cross talk between the signal transduction pathways to Pi, sucrose and phytohormones are involved in the regulation of expression of the three AtPHO1 homologues.

Effectiveness of fused magnesium potassium phosphate for marandu grass

The current high price of KCl and great dependence on importation to satisfy the Brazilian demand indicate the need for studies that evaluate the efficiency of other K sources, particularly those based on domestic raw material. For this purpose, a greenhouse experiment was conducted with samples of a sandy clay loam Typic Haplustox, in a completely randomized 4 x 3 x 2 factorial design: four K rates (0, 60, 120, and 180 mg kg-1), three sources (potassium chloride (KCl), fused magnesium potassium phosphate (FMPP) and a mixture of 70 % FMPP + 30 % KCl) and two particle sizes (100 and 60 mesh), with three replications. Potassium fertilization resulted in significant increases in shoot dry matter production and in K concentrations, both in soil and plants. The K source and particle size had no significant effect on the evaluated characteristics. Potassium critical levels in the soil and the shoots were 1.53 mmol c dm-3 and 19.1 g kg-1, respectively.

Les biomarqueurs dans la maladie de Fabry: relation entre Sphingosine-1 phosphate et Lyso-Gb3

Problématique : La maladie de Fabry est une maladie métabolique à stockage lysosomal. C'est une maladie héreditaire à transmission récessive qui concerne l'enzyme alpha-Galactosidase A. Le gène de l'alpha-Galactosidase A (GLA) se trouve au niveau du bras long du chromosome X «carté en Xq21.33-Xq22 ». L'enzyme muté ne recouvre plus son rôle catabolisateur et il ne métabolise pas le substrat globotriaosylceramide (Gb3). Par conséquence le Gb3 s'accumule dans tous les tissus. Dans les parois des vaisseaux sanguins le Gb3 s'accumule dans l'endothelium, la tunique interne des vaisseaux sanguins. Ce déficit métabolique se traduit par l'épaississement de la paroi vasculaire, des processus d'infarctus et ischémies du tissu cardiaque, rénal et cérébral. L'implication cardiaque de la maladie de Fabry est décrite chez plus de 78% des patients affectés par la maladie et se manifeste par une hypertrophie cardiaque du ventricule gauche. Toutefois, il n'existe pas de relation étroite entre hypertrophie cardiaque et le Gb3. La sphingosine 1-phosphate à été identifiée dans notre laboratoire et proposée comme facteur de croissance à l'origine du remodelage cardiovasculaire. De plus, la Globotriaosylsphingosine (Lyso-Gb3) à été aussi proposée comme facteur vasoactif chez les patients Fabry. Objectif : L'identification d'un biomarqueur pour le diagnostic et le suivi thérapeutique de la maladie de Fabry représente une domaine d'investigation active en recherche scientifique. Le Gb3 plasmatique ou dans les urines, la biopsie rénale ou cardiaque qui est mis en évidence grâce à la microscopie électronique sous forme de corps concentrique lamellaires, constituent les biomarqueurs classiques de la maladie de Fabry. Dernièrement, le Lyso-Gb3 et le Sphingosine-1 phosphate (S1P) ont été proposés comme marqueurs du remodelage cardiovasculaire. Le but de ce travail est de rassembler et de discuter la littérature concernant ces nouveaux marqueurs et, d'étudier une possible interaction entre Lyso-Gb3 et le S1P. Méthodologie : Rassembler la littérature scientifique et analyser l'implication de ces marqueurs dans la maladie de Fabry et leur effets cardiovasculaires. De plus, un travail expérimental est effectué. Ce travail consiste en l'identification d'une relation possible entre le Lyso-Gb3 et le S1P. Résultats : Avec ce travail on a cherché à actualiser et mettre à jour les notions concernant les biomarqueurs qui prennent place dans cette pathologie et les connaissances qu'on possède à ce jour sur les manifestations cardiovasculaires et neurologiques.La recherche d'un biomarqueur prime par le fait qu'un nombre considerable de patients est sous-diagnostiqués pour la maladie de Fabry et que entre les taux de substrat enzymatique accumulé dans les tissus et l'hypertrophie cardiaque, on peut constater une discordance. Grâce à ce travail expérimental, on a exclue la possibilité d'un effet précurseur du lyso-Gb3 pour le S1P. Nous avons montré que le Lyso-Gb3 est reconnu par les récepteurs du S1P avec des effets commun pour les S1P1-3 et différents pour le S1P2. Les taux du Lyso-Gb3 et du S1P doivent être mesuré chez les patients Fabry et une stratégie thérapeutique doit prendre en compte le rapport S1P/Lyso-Gb3.

PA21, a New Iron-Based Noncalcium Phosphate Binder, Prevents Vascular Calcification in Chronic Renal Failure Rats.

Chronic renal failure (CRF) is associated with the development of secondary hyperparathyroidism and vascular calcifications. We evaluated the efficacy of PA21, a new iron-based noncalcium phosphate binder, in controlling phosphocalcic disorders and preventing vascular calcifications in uremic rats. Rats with adenine-diet-induced CRF were randomized to receive either PA21 0.5, 1.5, or 5% or CaCO3 3% in the diet for 4 weeks, and were compared with uremic and nonuremic control groups. After 4 weeks of phosphate binder treatment, serum calcium, creatinine, and body weight were similar between all CRF groups. Serum phosphorus was reduced with CaCO3 3% (2.06 mM; P ≤ 0.001), PA21 1.5% (2.29 mM; P < 0.05), and PA21 5% (2.21 mM; P ≤ 0.001) versus CRF controls (2.91 mM). Intact parathyroid hormone was strongly reduced in the PA21 5% and CaCO3 3% CRF groups to a similar extent (1138 and 1299 pg/ml, respectively) versus CRF controls (3261 pg/ml; both P ≤ 0.001). A lower serum fibroblast growth factor 23 concentration was observed in the PA21 5%, compared with CaCO3 3% and CRF, control groups. PA21 5% CRF rats had a lower vascular calcification score compared with CaCO3 3% CRF rats and CRF controls. In conclusion, PA21 was as effective as CaCO3 at controlling phosphocalcic disorders but superior in preventing the development of vascular calcifications in uremic rats. Thus, PA21 represents a possible alternative to calcium-based phosphate binders in CRF patients.

Calculation and comparison of different permanent sample plot types

Summary

The emerging importance of the SPX domain-containing proteins in phosphate homeostasis

Plant growth and development are strongly influenced by the availability of nutrients in the soil solution. Among them, phosphorus (P) is one of the most essential and most limiting macro-elements for plants. In the environment, plants are often confronted with P starvation as a result of extremely low concentrations of soluble inorganic phosphate (Pi) in the soil. To cope with these conditions, plants have developed a wide spectrum of mechanisms aimed at increasing P use efficiency. At the molecular level, recent studies have shown that several proteins carrying the SPX domain are essential for maintaining Pi homeostasis in plants. The SPX domain is found in numerous eukaryotic proteins, including several proteins from the yeast PHO regulon, involved in maintaining Pi homeostasis. In plants, proteins harboring the SPX domain are classified into four families based on the presence of additional domains in their structure, namely the SPX, SPX-EXS, SPX-MFS and SPX-RING families. In this review, we highlight the recent findings regarding the key roles of the proteins containing the SPX domain in phosphate signaling, as well as providing further research directions in order to improve our knowledge on P nutrition in plants, thus enabling the generation of plants with better P use efficiency.

Rapid transgene expression in multiple precursor cell types of adult rat subventricular zone mediated by adeno-associated type 1 vectors.

Abstract The adult rat brain subventricular zone (SVZ) contains proliferative precursors that migrate to the olfactory bulb (OB) and differentiate into mature neurons. Recruitment of precursors constitutes a potential avenue for brain repair. We have investigated the kinetics and cellular specificity of transgene expression mediated by AAV2/1 vectors (i.e., adeno-associated virus type 2 pseudotyped with AAV1 capsid) in the SVZ. Self-complementary (sc) and single-stranded (ss) AAV2/1 vectors mediated efficient GFP expression, respectively, at 17 and 24 hr postinjection. Transgene expression was efficient in all the rapidly proliferating cells types, that is, Mash1(+) precursors (30% of the GFP(+) cells), Dlx2(+) neuronal progenitors (55%), Olig2(+) oligodendrocyte progenitors (35%), and doublecortin-positive (Dcx(+)) migrating cells (40%), but not in the slowly proliferating glial fibrillary acidic protein-positive (GFAP(+)) neural stem cell pool (5%). Because cell cycle arrest by wild-type and recombinant AAV has been described in primary cultures, we examined SVZ proliferative activity after vector injection. Indeed, cell proliferation was reduced immediately after vector injection but was normal after 1 month. In contrast, migration and differentiation of GFP(+) precursors were unaltered. Indeed, the proportion of Dcx(+) cells was similar in the injected and contralateral hemispheres. Furthermore, 1 month after vector injection into the SVZ, GFP(+) cells, found, as expected, in the OB granular cell layer, were mature GABAergic neurons. In conclusion, the rapid and efficient transgene expression in SVZ neural precursors mediated by scAAV2/1 vectors underlines their potential usefulness for brain repair via recruitment of immature cells. The observed transient precursor proliferation inhibition, not affecting their migration and differentiation, will likely not compromise this strategy.

Mycorrhizal effectiveness on physic nut as influenced by phosphate fertilization levels

In recent years, physic nut (Jatropha curcas L.) has attracted attention because of its potential for biofuel production. Although it is adapted to low-fertility soils, physic nut requires soil acidity corrections and addition of a considerable amount of fertilizer for high productivity. The objective of this research was to evaluate the effectiveness of arbuscular mycorrhizal fungi (AMF) (control without AMF inoculation, Gigaspora margarita inoculation or Glomus clarum inoculation) on increasing growth and yield of physic nut seedlings under different rates of P fertilization (0, 25, 50, 100, 200, and 400 mg kg-1 P soil) in greenhouse. The experiment was arranged in a completely randomized, block in a factorial scheme design with four replications. The physic nut plants were harvested 180 days after the beginning of the experiment. Mycorrhizal inoculation increased physic nut growth, plant P concentration and root P uptake efficiency at low soil P concentrations. The P use quotient of the plants decreased as the amount of P applied increased, and the P use efficiency index increased at low P levels and decreased at high P levels. Mycorrhizal root colonization and AMF sporulation were negatively affected by P addition. The highest mycorrhizal efficiency was observed when the soil contained between 7.8 and 25 mgkg-1 of P. The physic nut plants responded strongly to P application, independent of mycorrhizal inoculation.

Rarity types among plant species with high conservation priority in Switzerland

We investigated the ecogeographic characteristics of 118 Swiss plant species listed as those deserving highest conservation priority in a national conservation guide and classified them into the seven Rabinowitz' rarity types, taking geographic distribution, habitat rarity and local population size into account. Our analysis revealed that species with high conservation priority in Switzerland mostly have a very restricted geographic distribution in Switzerland and generally occur in rare habitats, but do not necessarily constitute small populations and are generally not endemics on a global scale. Moreover, species that are geographically very restricted on a regional scale are not generally restricted on a global scale. By analysing relationships between rarity and IUCN extinction risks for Switzerland, we demonstrated that species with the highest risk of extinction are those with the most restricted geographic distribution; whereas species with lower risk of extinction (but still high conservation priority) include many regional endemics. Habitat rarity and local population size appeared to be of minor importance for the assessment of extinction risk in Switzerland, but the total number of fulfilled rarity criteria still correlated positively with the severity of extinction risk. Our classification is the first preliminary assessment of the relative importance of each rarity type among endangered plant species of the Swiss flora and our results underline the need to distinguish between a regional and a global responsibility for the conservation of rare and endangered species.

Exudative mineral losses after serious burns: a clue to the alterations of magnesium and phosphate metabolism.

Hypomagnesemia and hypophosphatemia are frequent after severe burns; however, increased urinary excretion does not sufficiently explain the magnitude of the mineral depletion. We measured the mineral content of cutaneous exudates during the first week after injury. Sixteen patients aged 34 +/- 9 y (mean +/- SD) with thermal burns were studied prospectively and divided in 3 groups according to the extent of their burn injury and the presence or absence of mineral supplements: group 1 (n = 5), burns covering 26 +/- 5% of body surface; group 2 (n = 6), burns covering 41 +/- 10%; and group 3 (n = 5), burns covering 42 +/- 6% with prescription of magnesium and phosphate supplements. Cutaneous exudates were extracted from the textiles (surgical drapes, dressings, sheets, etc) surrounding the patients from day 1 to day 7 after injury. Mean magnesium serum concentrations decreased below reference ranges in 12 patients between days 1 and 4 and normalized thereafter. Phosphate, normal on day 0, was low during the first week. Albumin concentrations, normal on day 0, decreased and remained low. Urinary magnesium and phosphate excretion were within reference ranges and not larger in group 3. Mean daily cutaneous losses were 16 mmol Mg/d and 11 mmol P/d (largest in group 2). Exudative magnesium losses were correlated with burn severity (r = 0.709, P = 0.003). Cutaneous magnesium losses were nearly four times larger than urinary losses whereas cutaneous phosphate losses were smaller than urinary phosphate losses. Mean daily losses of both magnesium and phosphate were more than the recommended dietary allowances. Exudative losses combined with urinary losses largely explained the increased mineral requirements after burn injury.

The characteristics of gait in Charcot-Marie-Tooth disease types I and II.

Certain typical gait characteristics such as foot-drop and foot supination are well described in Charcot-Marie-Tooth disease. These are directly related to the primary disease and due to the weakness of ankle dorsiflexors and everters characteristic of this hereditary neuropathy. We analysed 16 subjects aged 8-52 years old (11 with type I, 5 with type II Charcot-Marie-Tooth disease) using three-dimensional gait analysis and identified kinematic features previously unreported. These patients showed a combination of tight tendo achillei, foot-drop, failure of plantar flexion and increased foot supination, but also presented with excessive internal rotation of the knee and/or tibia, knee hyperextension in stance, excessive external rotation at the hips and decreased hip adduction in stance (typical of a broad based gait). These proximal features could have been an adaptation to or consequence of the disrupted ankle and foot biomechanics, however a direct relation to the neuropathy is also possible since sub-normal muscle power was observed at the proximal levels in most subjects on both manual testing and kinetic analysis. Gait analysis is a useful tool in defining the characteristic gait of patients with Charcot-Marie-Tooth disease.

Spectroscopic quantification of soil phosphorus forms by 31p-nmr after nine years of organic or mineral fertilization

Long-standing applications of mineral fertilizers or types of organic wastes such as manure can cause phosphorus (P) accumulation and changes in the accumulated P forms in the soil. The objective of this research was to evaluate the forms of P accumulated in soils treated with mineral fertilizer or different types of manure in a long-term experiment. Soil was sampled from the 0-5 cm layer of plots fertilized with five different nutrient sources for nine years: 1) control without fertilizer; 2) mineral fertilizer at recommended rates for local conditions; 3) 5 t ha-1 year-1 of moist poultry litter; 4) 60 m³ ha-1 year-1 of liquid cattle manure and 5) 40 m³ ha-1 year-1 of liquid swine manure. The 31P-NMR spectra of soil extracts detected the following P compounds: orthophosphate, pyrophosphate, inositol phosphate, glycerophosphate, and DNA. The use of organic or mineral fertilizer over nine years did not change the soil P forms but influenced their concentration. Fertilization with mineral or organic fertilizers stimulated P accumulation in inorganic forms. Highest inositol phosphate levels were observed after fertilization with any kind of manure and highest organic P concentration in glycerophosphate form in after mineral or no fertilization.