Collimated scanning LS-INAA for testing trace elements homogeneity in Brazilian coffee beans

The degree of homogeneity is normally assessed by the variability of the results of independent analyses of several (e.g., 15) normal-scale replicates. Large sample instrumental neutron activation analysis (LS-INAA) with a collimated Ge detector allows inspecting the degree of homogeneity of the initial batch material, using a kilogram-size sample. The test is based on the spatial distributions of induced radioactivity. Such test was applied to samples of Brazilian whole (green) coffee beans (Coffea arabica and Coffea canephora) of approximately I kg in the frame of development of a coffee reference material. Results indicated that the material do not contain significant element composition inhomogeneities between batches of approximately 30-50 g, masses typically forming the starting base of a reference material.

Status of chemical elements in Atlantic Forest tree species near an industrial complex

Environmental quality assessment studies have been conducted with tree species largely distributed in the Atlantic Forest. Leaf and soil samples were collected in the conservation unit Parque Estadual da Serra do Mar (PESM) nearby the industrial complex of Cubatao, Sao Paulo State, Brazil, and analyzed for chemical elements by instrumental neutron activation analysis. Results were compared to background values obtained in the Parque Estadual Carlos Botelho (PECB). The higher As, Fe, Hg and Zn mass fractions in the tree leaves of PESM indicated anthropogenic influence on this conservation unit.

Chemical characterization of agricultural supplies applied to organic tomato cultivation

The agricultural supplies used in the organic system to control pests and diseases as well as to fertilize soil are claimed to be beneficial to plants and innocuous to human health and to the environment. The chemical composition of six agricultural supplies commonly used in the organic tomato culture, was evaluated by instrumental neutron activation analysis (INAA). Results were compared to the maximum limits established by the Environment Control Agency of the Sao Paulo State (CETESB) and the Guidelines for Organic Quality Standard of Instituto Biodinamico (IBD). Concentrations above reference values were found for Co, Cr and Zn in compost, Cr and Zn in cattle manure and Zn in rice bran.

Elemental composition changes in citrus affected by the CVC disease

The citrus variegated chlorosis (CVC) disease results in serious economical losses for the Brazilian citriculture. The influence of CVC disease on the elemental composition of citrus plants was investigated. Leaves of sweet orange varieties Hamlin, Pera Rio and Valencia were collected from healthy and CVC-affected trees for chemical characterization by instrumental neutron activation analysis (INAA). Significant differences between healthy and CVC-affected leaves were identified for Ca, Ce, Co, Eu, Fe, K, La, Na, Nd, Rb, Sc and Sm. Rare earth elements presented consistently higher mass fractions in the healthy leaves.

Chemical composition of tomato seeds affected by conventional and organic production systems

Tomato is amongst the most consumed vegetables in the world, not only for its culinary versatility but also for its high nutritional value. In the last years, consumers have shown an increased concern regarding food origin and safety. The organic tomato production has been a promising alternative for the consumer offering a safer food in relation to environmental, social and nutritional aspects. This study assessed the chemical composition of tomato seeds produced in both conventional and organic systems by INAA. The results showed significant differences (P <= 0.05) in the mass fractions of Br, Cs, Eu, Fe, K, Mo, Na, Rb and Sm between both systems, indicating influence of the crop management adopted in the different tomato production systems.

Sampling study in milk storage tanks by INAA

This study investigated the representativeness of samples for assessing chemical elements in milk bulk tanks. Milk samples were collected from a closed tank in a dairy plant and from an open top tank in a dairy farm. Samples were analyzed for chemical elements by instrumental neutron activation analysis (INAA). For both experiments, Br, Ca, Cs, K, Na, Rb and Zn did not present significant differences between samples thereby indicating the appropriateness of the sampling procedure adopted to evaluate the analytes of interest.

Assessing sample representativeness for inorganic chemical investigation of invertebrates by INAA

The quality of environmental studies depends on the utilization of adequate sampling protocol and analytical method for obtaining reliable results and minimizing analytical uncertainties. In order to demonstrate the applicability of INAA for determining chemical element composition of invertebrates, this work evaluated sample representativeness in terms of subsampling and sample size. Br, Co, Fe, K, Na, Sc and Zn could be determined in very small samples despite increasing of analytical uncertainties. Special attention should be directed to invertebrate species with small structures because of the high chemical variation observed among different sample sizes tested.

The role of local and systemic renin angiotensin system activation in a genetic model of sympathetic hyperactivity-induced heart failure in mice

Sympathetic hyperactivity (SH) and renin angiotensin system (RAS) activation are commonly associated with heart failure (HF), even though the relative contribution of these factors to the cardiac derangement is less understood. The role of SH on RAS components and its consequences for the HF were investigated in mice lacking alpha(2A) and alpha(2C) adrenoceptor knockout (alpha(2A)/alpha(2C) ARKO) that present SH with evidence of HF by 7 mo of age. Cardiac and systemic RAS components and plasma norepinephrine (PN) levels were evaluated in male adult mice at 3 and 7 mo of age. In addition, cardiac morphometric analysis, collagen content, exercise tolerance, and hemodynamic assessments were made. At 3 mo, alpha(2A)/alpha(2C)ARKO mice showed no signs of HF, while displaying elevated PN, activation of local and systemic RAS components, and increased cardiomyocyte width (16%) compared with wild-type mice (WT). In contrast, at 7 mo, alpha(2A)/alpha(2C)ARKO mice presented clear signs of HF accompanied only by cardiac activation of angiotensinogen and ANG II levels and increased collagen content (twofold). Consistent with this local activation of RAS, 8 wk of ANG II AT(1) receptor blocker treatment restored cardiac structure and function comparable to the WT. Collectively, these data provide direct evidence that cardiac RAS activation plays a major role underlying the structural and functional abnormalities associated with a genetic SH-induced HF in mice.

The Penicillium chrysogenum aclA gene encodes a broad-substrate-specificity acyl-coenzyme A ligase involved in activation of adipic acid, a side-chain precursor for cephem antibiotics

Activation of the cephalosporin side-chain precursor to the corresponding CoA-thioester is an essential step for its incorporation into the P-lactam backbone. To identify an acyl-CoA ligase involved in activation of adipate, we searched in the genome database of Penicillium chrysogenum for putative structural genes encoding acyl-CoA ligases. Chemostat-based transcriptome analysis was used to identify the one presenting the highest expression level when cells were grown in the presence of adipate. Deletion of the gene renamed aclA, led to a 32% decreased specific rate of adipate consumption and a threefold reduction of adipoyl-6-aminopenicillanic acid levels, but did not affect penicillin V production. After overexpression in Escherichia coli, the purified protein was shown to have a broad substrate range including adipate. Finally, protein-fusion with cyan-fluorescent protein showed co-localization with microbody-borne acyl-transferase. Identification and functional characterization of aclA may aid in developing future metabolic engineering strategies for improving the production of different cephalosporins. (C) 2009 Elsevier Inc. All rights reserved.

Time stability of soil water storage measured by neutron probe and the effects of calibration procedures in a small watershed

The knowledge of soil water storage (SWS) of soil profiles is crucial for the adoption of vegetation restoration practices. With the aim of identifying representative sites to obtain the mean SWS of a watershed, a time stability analysis of neutron probe evaluations of SWS was performed by the means of relative differences and Spearman rank correlation coefficients. At the same time, the effects of different neutron probe calibration procedures were explored on time stability analysis. mean SWS estimation. and preservation of the spatial variability of SWS. The selected watershed, with deep gullies and undulating slopes which cover an area of 20 ha, is characterized by an Ust-Sandiic Entisol and an Aeolian sandy soil. The dominant vegetation species are bunge needlegrass (Stipa bungeana Trim) and korshinsk peashrub (Carugano Korshinskii kom.). From June 11, 2007 to July 23,2008, SWS of the top1 m soil layer was evaluated for 20 dates, based on neutron probe data of 12 sampling sites. Three calibration procedures were employed: type 1, most complete, with each site having its own linear calibration equation (TrE); type II. with TrE equations extended over the whole field: and type III, with one single linear calibration curve for the whole field (UnE) and also correcting its intercept based on site specific relative difference analysis (RdE) and on linear fitting of data (RcE), both maintaining the same slope. A strong time stability of SWS estimated by TrE equations was identified. Soil particle size and soil organic matter content were recognized as the influencing factors for spatial variability of SWS. Land use influenced neither the spatial variability nor the time stability of SWS. Time stability analysis identified one site to represent the mean SWS of the whole watershed with mean absolute percentage errors of less than 10%, therefore. this site can be used as a predictor for the mean SWS of the watershed. Some equations of type II were found to be unsatisfactory to yield reliable mean SWS values or in preserving the associated soil spatial variability. Hence, it is recommended to be cautious in extending calibration equations to other sites since they might not consider the field variability. For the equations with corrected intercept (type III), which consider the spatial variability of calibration in a different way in relation to TrE, it was found that they can yield satisfactory means and standard deviation of SWS, except for the RdE equations, which largely leveled off the SWS values in the watershed. Correlation analysis showed that the neutron probe calibration was linked to soil bulk density and to organic matter content. Therefore, spatial variability of soil properties should be taken into account during the process of neutron probe calibration. This study provides useful information on the mean SWS observation with a time stable site and on distinct neutron probe calibration procedures, and it should be extended to soil water management studies with neutron probes, e.g., the process of vegetation restoration in wider area and soil types of the Loess Plateau in China. (C) 2009 Elsevier B.V. All rights reserved.

Mass Spectrometric Analysis of a Cyclic 7,8-Butanoguanine Adduct of N-Nitrosopyrrolidine: Comparison to Other N-Nitrosopyrrolidine Adducts in Rat Hepatic DNA

The well established rat hepatocarcinogen N-nitrosopytrolidine (NPYR, 1) requires metabolic activation to DNA adducts to express its carcinogenic activity. Among the NPYR-DNA adducts that have been identified, the cyclic 7,8-butanoguanine adduct 2-amino-6,7,8,9-tetrahydro-9-hydroxypyrido[2,1-f]purine-4(3H)-one (6) has been quantified using moderately sensitive methods, but its levels have never been compared to those of other DNA adducts of NPYR in rat hepatic DNA. Therefore, in this study, we developed a sensitive new LC-ESI-MS/MS-SRM method for the quantitation of adduct 6 and compared its levels to those of several other NPYR-DNA adducts formed by different mechanisms. The new method was shown to be accurate and precise, with good recoveries and low fmol detection limits. Rats were treated with NPYR by gavage at doses of 46, 92, or 184 mg/kg body weight and sacrificed 16 h later. Hepatic DNA was isolated and analyzed for NPYR-DNA adducts. Adduct 6 was by far the most prevalent, with levels ranging from about 900-3000 mu mol/mol Gua and responsive to dose. Levels of adducts formed from crotonaldehyde, a metabolite of NPYR, were about 0.2-0.9 mu mol/mol dGuo, while those of adducts resulting from reaction with DNA of tetrahydrofuranyl-like intermediates were in the range of 0.01-4 mu mol/mol deoxyribonucleoside. The results of this study demonstrate that, among typical NPYR-DNA adducts, adduct 6 is easily the most abundant in hepatic DNA. Since previous studies have shown that it can be detected in the urine of NPYR-treated rats, the results suggest that it is a potential candidate as a biomarker for assessing human exposure to and metabolic activation of NPYR.

Genetic analysis of complement C1s deficiency associated with systemic lupus erythernatosus highlights alternative splicing of normal C1s gene

Deficiencies of complement proteins of the classical pathway are strongly associated with the development of autoimmune diseases. Deficiency of Clr has been observed to occur concomitantly with deficiency in Cls and 9 out of 15 reported cases presented systemic lupus erythernatosus (SLE). Here, we describe a family in which all four children are deficient in Cls but only two of them developed SLE. Hemolytic activity mediated by the alternative and the lectin pathways were normal, but classical pathway activation was absent in all children`s sera. Cls was undetectable, while in the parents` sera it was lower than in the normal controls. The levels of Clr observed in the siblings and parents sera were lower than in the control, while the concentrations of other complement proteins (C3, C4, MBL and MASP-2) were normal in all family members. Impairment of Cls synthesis was observed in the patients` fibroblasts when analyzed by confocal microscopy. We show that all four siblings are homozygous for a mutation at position 938 in exon 6 of the Cls cDNA that creates a premature stop codon. Our investigations led us to reveal the presence of previously uncharacterized splice variants of Cls mRNA transcripts in normal human cells. These variants are derived from the skipping of exon 3 and from the use of an alternative 3` splice site within intron I which increases the size of exon 2 by 87 nucleotides. (c) 2007 Elsevier Ltd. All rights reserved.

Chemical composition of bovine milk from Minas Gerais State, Brazil

Aiming at international competitiveness of the Brazilian dairy sector, new governmental policies were released to improve quality and safety of bovine milk. In this context, it is important to quantify essential and toxic chemical elements. Here, the composition of milk samples taken at 32 dairy farms in Minas Gerais State was assessed by instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS), besides the evaluation of usual quality parameters. Significant differences were found for Ba, K, Na and fat content amongst dairy farms with diverse quality levels established on basis of somatic cell and total bacterial count.

Biomolecular interaction analysis of IFN gamma-induced signaling events in whole-cell lysates: Prevalence of latent STAT1 in high-molecular weight complexes

The basic framework for the JAK/STAT pathway is well documented. Recruitment of latent cytoplasmic STAT transcription factors to tyrosine phosphorylated docking sites on cytokine receptors and their JAK-mediated phosphorylation instigates their translocation to the nucleus and their ability to bind DNA, The biochemical processes underlying recruitment and activation of this pathway have commonly been studied in reconstituted in vitro systems using previously defined recombinant signaling components. We have dissected the Interferon gamma (IFN gamma) signal transduction pathway in crude extracts from wild-type and STAT1-negative mutant cell Lines by real-time BIAcore analysis, size-exclusion (SE) chromatography and immune-detection. The data indicate that in detergent-free cell extracts: (1) the phospho-tyrosine (Y440P)-containing peptide motif of the IFN gamma-receptor ct-chain interacts directly with STAT1, or STAT1 complexes, and no other protein; (2) nonactivated STAT 1 is present in a higher molecular weight complex(es) and, at least for IFN gamma-primed cells, is available for recruitment to the activated IFN gamma-receptor from only a subset of such complexes; (3) activated STAT1 is released from the receptor as a monomer.

Thermogravimetric analysis of carbon deposition over Ni/gamma-Al2O3 catalysts in carbon dioxide reforming of methane

Carbon formation on Ni/gamma-Al2O3 catalysts and its kinetics during methane reforming with carbon dioxide was studied in the temperature range of 500-700 degrees C using a thermogravimetric analysis technique. The activation energies of methane cracking, carbon gasification in CO2, as well as carbon deposition in CO2-CH4 reforming were obtained. The results show that the activation energy for carbon gasification is larger than that of carbon formation in methane cracking and that the activation energy of coking in CO2-CH4 reforming is also larger than that of methane decomposition to carbon. The dependencies of coking rate on partial pressures of CH4 and CO2 indicate that methane decomposition is the main route for carbon deposition. A mechanism and kinetic model for carbon deposition is proposed.