Millet seeds mixed with phosphate fertilizers

O tamanho reduzido das sementes de milheto dificulta sua semeadura uniforme, principalmente para os produtores que não possuem semeadoras apropriadas. Assim, a mistura das sementes com os fertilizantes fosfatados vem sendo utilizada para facilitar a semeadura. Entretanto, o período de contato pode provocar prejuízos na germinação e no vigor. Avaliou-se a qualidade fisiológica das sementes de milheto submetidas a diferentes períodos de contato (0, 6, 12, 24, 48, 72, 96 e 120h) com os fertilizantes superfosfato simples (SFS) e superfosfato triplo (SFT), em um experimento em delineamento inteiramente casualizado em esquema fatorial 8x2 (n=4). Os atributos químicos e físicos dos fertilizantes foram previamente determinados. Foi utilizada a proporção de 1 kg de sementes para 2,5 kg de fertilizante. Após manutenção da mistura em saco plástico no laboratório, as sementes foram separadas dos fertilizantes e submetidas à determinação de umidade, germinação, primeira contagem e condutividade elétrica. Paralelamente, na casa de vegetação, em caixas plásticas contendo terra, determinou-se a emergência e o índice de velocidade de emergência, sem e com a manutenção dos fertilizantes. Porque apresentam resíduos ácidos, tanto SFS como SFT afetaram de maneira semelhante e negativamente a germinação e o vigor das sementes de milheto em mistura, na medida em que se aumentou o período de contato.

Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate

Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich waters by ultrafiltration and a resin XAD 8 procedure. The HS-metal species studied were formed by complexation with Cd(II), Ni(II), Cu(II), Mn(II) and Pb(II) as a function of time and the ratio ions to HSs. The kinetics and reaction order of this exchange process were studied. At the beginning (<3 min), the labile metal fractions are separated relatively quickly. After 3 min, the separation of the metal ions proceeds with uniform half-lives of about 12-14 min, revealing rather slow first-order kinetics. The metal exchange between HSs and CellPhos exhibited the following order of metal lability with the studied HSs: Cu > Pb > Mn > Ni > Cd. The required metal determinations were carried out by atomic absorption spectrometry.

Discovery of novel Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase inhibitors

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Factors determining rock phosphate solubilization by microorganisms isolated from soil

Forty two soil isolates (31 bacteria and 11 fungi) were studied for their ability to solubilize rock phosphate and calcium phosphate in culture medium. Eight bacteria and 8 fungi possessed solubilizing ability. Pseudomonas cepacia and Penicillium purpurogenum showed the highest activity. There was a correlation between final pH value and titratable acidity (r = - 0.29 to -0.87) and between titratable acidity and soluble phosphate (r = 0.22 to 0.99). Correlation values were functions of insoluble phosphate and of the group of microorganisms considered. A high correlation was observed between final pH and soluble phosphate only for the rock phosphates inoculated with the highest concentration of solubilizing bacteria (r = -0.73 to -0.98).

Kinetics and crystal structure of human purine nucleoside phosphorylase in complex with 7-methyl-6-thio-guanosine

Purine nucleoside phosphorylase (PNP) catalyzes the reversible phosphorolysis of nucleosides and deoxynucleosides, generating ribose 1-phosphate and the purine base, which is an important step of purine catabolism pathway. The lack of such an activity in humans, owing to a genetic disorder, causes T-cell impairment, and drugs that inhibit this enzyme may have the potential of being utilized as modulators of the immunological system to treat leukemia, autoimmune diseases, and rejection in organ transplantation. Here, we describe kinetics and crystal structure of human PNP in complex with 7-methyl-6-thio-guanosine, a synthetic substrate, which is largely used in activity assays. Analysis of the structure identifies different protein conformational changes upon ligand binding, and comparison of kinetic and structural data permits an understanding of the effects of atomic substitution on key positions of the synthetic substrate and their consequences to enzyme binding and catalysis. Such knowledge may be helpful in designing new PNP inhibitors. © 2005 Elsevier Inc. All rights reserved.

Agronomic effectiveness of cationic phosphate impurities present in superphosphate fertilizers as affected by soil pH

The general concept that low-water-soluble phosphorus (P) fertilizers should be more agronomically effective when applied to acidic soils was developed based on sources containing mainly calcium (Ca)-P compounds, but it may not hold true for sources with different chemical composition. To obtain information related to this issue, two important iron (Fe)-potassium (K)-P compounds present in superphosphates [Fe 3 KH 8 (PO 4 ) 6·6H 2 O, H8, and Fe 3 KH 14 (PO 4 ) 8·4H 2 O, H14] were prepared and characterized. These P sources were used to provide 30 and 60 mg P kg -1 as neutral ammonium citrate (NAC)+H 2 O-soluble P. Reagent-grade monocalcium phosphate (MCP) was used as a standard P source with high water solubility with an additional rate of 120 mg P kg -1 included. Also, mixtures of both Fe-K-P compounds and MCP were prepared to provide 0, 25, 50, 75, and 100% of the total P as MCP. All sources were applied to a clayey loamy acid soil (pH 5.3) classified as Rhodic Kanhapludult. The soil was incubated at two rates (0 and 10 g kg -1 ) of lime, which resulted in pH 5.4 and 6.8. Upland rice was cultivated to maturity. The H14 compound confirmed to be a highly effective source of P for the rice plants at both soil pH, as opposed to the H8, which was poorly effective when applied alone. When mixed with water-soluble P (WSP), the H8 was able to provide P to the plants with the maximum yield of upland rice reached with 54.8 and 80.5% of WSP for pH 5.4 and 6.8, respectively. The high agronomic performance of the H14 compound clearly indicates that this low-water-soluble P source cannot be deemed as ineffective at high soil pH. Copyright © Taylor & Francis Group, LLC.

Solubilization of iron phosphate by free or immobilized spores and pellets of Aspergillus niger

The production of pellets by Aspergillus niger and the FePO 4 (FeP) solubilization through the use of free or immobilized spores and pellets were studied. The media Sabouraud, MS-FeP, MS-K 2HPO 4, Czapek and Malt were used for pellets yield. Enhanced growth and pellets production were found in the Sabouraud and MS-FeP than those produced by the other media. Pellets produced in Sabouraud were larger in size and formed well-defined spheres than those produced in MS-FeP. Pellets amounts varying from 2 to 8 mg mL, -1 were inoculated in the MS-FeP medium. The greatest quantity of solubilized FeP was found when 6 mg of pellets mL, -1 were used. While the free spores were the worst form used for FeP solubilization in culture medium, free pellets allowed for the production of the greatest quantities of soluble phosphate, even after repeated use of the pellets. In the soil, pellets solubilized similar quantities of FeP compared to the immobilized A. niger spores and can be used with advantage since they are easily produced. © 2010 Academic Journals Inc.

Inoculation of salivary gland extracts obtained from female of Rhipicephalus sanguineus (Latreille, 1806) (Acari, Ixodidae) with 2, 4, and 6 days of feeding in rabbit: I - Histopathology of the feeding lesion

This study analyzed the histopathology of rabbit skin, previously immunized with SGE2, SGE4, and SGE6 gland extracts prepared from salivary glands of Rhipicephalus sanguineus female with 2, 4, and 6 days of feeding, at the region of the R. sanguineus female feeding lesion 2, 4, and 6 days after tick attachment. In this work, infestation-naïve New Zealand White rabbits were inoculated either with the extracts (test group (TG)) or with phosphate buffer and complete Freund's adjuvant mixture (control group 2 (CG2)). Each extract-inoculated- (TG and CG2) and non-inoculated (CG1) rabbit was subsequently infested with R. sanguineus. Skin biopsies were collected from the rabbit at the tick feeding lesion at 2, 4, and 6 days of feeding. Results revealed that rabbit immunization with gland extracts induced acquisition of resistance against this species. It should be stated that the SGE4 extract was the most effective in developing an immune-inflammatory response against ectoparasites, being this process characterized by the presence of an early and intense inflammatory cell infiltrate. On the other hand, SGE6 extract caused a later appearance of resistance with less infiltrate occurrence and intense edema at the feeding lesion site. As to the inflammatory process deriving from SGE2 extract inoculation, it was the less intense. It was concluded that immunization with different extracts from R. sanguineus female salivary glands did not change microscope features of the inflammatory process, although an earlier or more intense and later response, which was also dependent on the inoculate extract, was noticed. © 2012 Springer-Verlag Berlin Heidelberg.

Use of different carbon sources in cultivation of baker's yeast for production of glycerol-3-phosphate dehydrogenase

The physiological state of yeast cells changes during culture growth as a consequence of environmental changes (nutrient limitations, pH and metabolic products). Cultures that grow exponentially are heterogeneous cell populations made up of cells regulated by different metabolic and/or genetic control systems. The strain of baker's yeast selected by plating commercial compressed yeast was used for the production of glycerol-3- phosphate dehydrogenase. Glycerol-3-phosphate dehydrogenase (GPD) has been widely used in the enzyme assays with diverse compounds of industrial interest, such as glycerol or glycerol phosphate, as well as a number of important bioanalytical applications. Each cell state determines the level of key enzymes (genetic control), fluxes through metabolic pathways (metabolic control), cell morphology and size. The present study was carried out to determine the effects of environmental conditions and carbon source on GPD production from baker's yeast. Glucose, glycerol, galactose and ethanol were used as carbon sources. Glycerol and ethanol assimilations required agitation, which was dependent on the medium volume in the fermentation flask for the greatest accumulation of intracellular GPD. Enzyme synthesis was also affected by the initial pH of the medium and inoculum size. The fermentation time required for a high level of enzyme formation decreased with the inoculum size. The greatest amount of enzyme (0.45 U/ml) was obtained with an initial pH of 4.5 in the medium containing ethanol or glycerol. The final pH was maintained in YP-ethanol, but in the YP-glycerol the final pH increased to 6.9 during growth.

Voltammetric determination of phosphate in brazilian biodiesel using two different electrodes

The presence of contaminants, such as phosphate, in biodiesel, has several drawbacks for instance: current engines perform poorly, fuel tanks deteriorate, catalytic conversion is damaged, and particles emission is increased. Therefore, biodiesel quality control is extremely important for biodiesel acceptance and commercialization worldwide. In this context, a bare glassy carbon electrode (GCE) and another chemically modified electrode with iron hexacyanoferrate (Prussian Blue – PB) were developed for determination of phosphate in biodiesel. The LODs of 6.44 and 1.19 mg kg−1, and LOQs of 21.43 and 3.97 mg kg−1 were obtained for the bare GCE and the PB-modified GCE, respectively. The methodology was employed for analysis of Brazilian biodiesel samples, and it led to satisfactory results, demonstrating its potential application for biodiesel quality control. Additionally, recovery and interference tests were conducted, which revealed that the developed methods are suitable for analysis of phosphate in biodiesel samples.

Desenvolvimento de sistem biomimético para análise de 3,5,6-Tricloro-2-piridinol, o principal metabólito do clorpirifós

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Square-wave voltammetric determination of rutin in pharmaceutical formulations using a carbon composite electrode modified with copper (II) phosphate immobilized in polyester resin

Descreve-se um eletrodo de carbono modificado com fosfato de cobre (II) imobilizado em uma resina de poliéster (Cu₃(PO₄)₂-Poly) para a determinação de rutina em amostras farmacêuticas por voltametria de onda quadrada. O eletrodo modificado permite a determinação de rutina em potencial (0.20 V vs Ag / AgCl (3,0 mol L^-1 KCl)) menor que o observado em um eletrodo não modificado. Verificou-se que a corrente de pico foi linear com a concentração de rutina na faixa de 9,9 × 10^-8 a 2,5 × 10^-6 mol L^-1, com um limite de detecção de 1,2 × 10^-8 mol L^-1. A resposta do eletrodo foi estável, sem variação significativa dentro de várias horas de operação contínua. A morfologia da superfície do eletrodo modificado foi caracterizada por microscopia eletrônica de varredura (MEV) e pelo sistema de energia dispersiva de raios-X (EDX). Os resultados obtidos foram precisos e exatos. Ademais, estes resultados estão de acordo com aqueles obtidos pelo método cromatográfico a um nível de confiança de 95%.

Mannose-binding lectin gene polymorphism and risk factors for cardiovascular disease in postmenopausal women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

EPR, optical absorption and luminescence studies of Cr3+-doped antimony phosphate glasses

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)