Changes in soluble carbohydrates and starch amounts during somatic and zygotic embryogenesis of Acca sellowiana (Myrtaceae)

Comparative analysis of zygotic and somatic embryogenesis of Acca sellowiana showed higher amounts of sucrose, fructose, raffinose, and myo-inositol in zygotic embryos at different developmental stages than in corresponding somatic ones. These differences were mostly constant. In general, glucose levels were significantly lower than the other soluble carbohydrates analyzed, showing minor variation in each embryo stage. Despite the presence of sucrose in the culture medium, its levels conspicuously diminished in somatic embryos compared with the zygotic ones. Raffinose enhanced parallel to embryo development, regardless of its zygotic or somatic origin. Analysis of the soluble carbohydrate composition of mature zygotic cotyledon used as explant pointed out fructose, glucose, myo-inositol, sucrose, and raffinose as the most important. Similar composition was also found in the corresponding somatic cotyledon. Total soluble carbohydrates varied inversely, decreasing in zygotic embryos and increasing in somatic embryos until the 24th d, at which time they increased rapidly about sixfold in zygotic embryos until the 27th d, a period coinciding with the zygotic proembryos formation. Such condition seems to reflect directly the variation of endogenous sucrose level, mainly because glucose and fructose diminished continuously during this time period. This means that, in terms of soluble sugars, zygotic embryo formation occurred under a situation represented by high sucrose amounts, simultaneously with low fructose and glucose levels, while in contrast, somatic embryo formation took place under an endogenous sugar status characterized by a substantial fructose enhancement. Starch levels increased continuously in zygotic embryos and decreased in somatic ones, the reverse to what was found in fructose variation. Starch accumulation was significantly higher in somatic torpedo and cotyledonary embryos than in the corresponding zygotic ones.

Free Cyclitol, Soluble Carbohydrate and Protein Contents in Vigna unguiculata and Phaseolus vulgaris Bean Sprouts

Seeds sprouts have been used as a good source of basic nutrients and nutraceutical compounds. The high nutritional value of seeds derives from the deposition of compounds during development. However some of these molecules are used in metabolic processes like germination, which leads to a considerable variation in their concentrations once these events are completed. In this work, we investigate the levels of inositols (myo-inositol, D-pinitol and ononitol), soluble carbohydrates and proteins in cotyledons of Phaseolus vulgaris and Vigna unguiculata sprouts. Sprouting increased myo-inositol and glucose content and reduction of raffinose and ononitol was observed. The protein levels increased in P. vulgaris and decreased in V. unguiculata sprouting. The level of sucrose was maintained in both sprouts. D-Pinitol was detected only in quiescent seeds. Our results suggested that bean sprout is an important source of proteins, sucrose, glucose and myo-inositol. Additionally, bean sprouts have low levels of raffinose, an antinutritional compound.

AMP hydrolysis in soluble and microsomal rat cardiac cell fractions: kinetic characterization and molecular identification of 5 `-nucleotidase

The present study describes the enzymatic properties and molecular identification of 5`-nucleotidase in soluble and microsomal fractions from rat cardiac ventricles. Using AMP as a substrate, the results showed that the cation and the concentration required for maximal activity in the two fractions was magnesium at a final concentration of 1 mM. The pH optimum for both fractions was 9.5. The apparent K-m (Michaelis constant) values calculated from the Eadie-Hofstee plot were 59.7 +/- 10.4 mu M and 134.8 +/- 32.1 mu M, with V-max values of 6.7 +/- 0.4 and 143.8 +/- 23.8 nmol P-i/min/mg of protein (means +/- S.D., n = 4) from soluble and microsomal fractions respectively. Western blotting analysis of ecto-5`-nucleotidase revealed a 70 kDa protein in both fractions, with the major proportion present in the microsomal fraction. The presence of these enzymes in the heart probably has a physiological function in adenosine signalling. Furthermore, the presence of ecto-5`-nucleotidase in the microsomal fraction could have a role in the modulation of the excitation-contraction-coupling process through involvement of the Ca2+ influx into the sarcoplasmic reticulum. The measurement of maximal enzyme activities in the two fractions highlights the potential capacity of the different pathways of purine metabolism in the heart.

Macrophage migration inhibitory factor is up-regulated in human first-trimester placenta stimulated by soluble antigen of Toxoplasma gondii, resulting in increased monocyte adhesion on villous explants

Considering the potential role of macrophage migration inhibitory factor (MIF) in the inflammation process in placenta when infected by pathogens, we investigated the production of this cytokine in chorionic villous explants obtained from human first-trimester placentas stimulated with soluble antigen from Toxoplasma gondii (STAg). Parallel cultures were performed with villous explants stimulated with STAB, interferon-gamma (IFN-gamma), or STAB plus IFN-gamma. To assess the role of placental MIF on monocyte adhesiveness to human trophoblast, explants were co-cultured with human myelomonocytic THP-1 cells in the presence or absence of supernatant from cultures treated with STAB (SPN), SPN plus anti-MIF antibodies, or recombinant MIF. A significantly higher concentration of MIF was produced and secreted by villous explants treated with STAB or STAB plus IFN-gamma after 24-hour culture. Addition of SPN or recombinant MIF was able to increase THP-1 adhesion, which was inhibited after treatment with anti-MIF antibodies. This phenomenon was associated with intercellular adhesion molecule expression by villous explants. Considering that the processes leading to vertical dissemination of T. gondii remain widely unknown, our results demonstrate that MIF production by human first-trimester placenta is up-regulated by parasite antigen and may play an essential role as an autocrine/paracrine mediator in placental infection by T. gondii.

Soluble one-dimensional particle conservation models with infinitely many absorbing states

Particle conservation lattice-gas models with infinitely many absorbing states are studied on a one-dimensional lattice. As one increases the particle density, they exhibit a phase transition from an absorbing to an active phase. The models are solved exactly by the use of the transfer matrix technique from which the critical behavior was obtained. We have found that the exponent related to the order parameter, the density of active sites, is 1 for all studied models except one of them with exponent 2.

Absolute determination of soluble potassium in tea infusion by gamma-ray spectroscopy

Potassium content in tea brew was determined by gamma-ray spectroscopy, Using the 1461 keV gamma-ray fro M (40)K, the naturally occurring radioactive isotope of potassium. We measured radiation with a shielded HPGe detector from individual test samples of tea leaves, before and after infusion preparation, and from commercial instant tea powder. The correction factor for the gamma-ray self-absorption in the extended source was determined with the help of Monte-Carlo simulations. This gamma-ray spectroscopy technique enabled the absolute determination of potassium content with a relative uncertainty smaller than 4%, at the one standard deviation confidence level, showing the feasibility of this method. An experiment to evaluate a possible systematic Uncertainty due to K distribution heterogeneity in the sample was performed, with file result that the corresponding relative standard deviation is smaller than 2% at 95% confidence level. (C) 2009 Elsevier Ltd. All rights reserved.

Texture analysis using graphs generated by deterministic partially self-avoiding walks

Texture is one of the most important visual attributes for image analysis. It has been widely used in image analysis and pattern recognition. A partially self-avoiding deterministic walk has recently been proposed as an approach for texture analysis with promising results. This approach uses walkers (called tourists) to exploit the gray scale image contexts in several levels. Here, we present an approach to generate graphs out of the trajectories produced by the tourist walks. The generated graphs embody important characteristics related to tourist transitivity in the image. Computed from these graphs, the statistical position (degree mean) and dispersion (entropy of two vertices with the same degree) measures are used as texture descriptors. A comparison with traditional texture analysis methods is performed to illustrate the high performance of this novel approach. (C) 2011 Elsevier Ltd. All rights reserved.

Tetrachlorocarbonyliridates: Water-Soluble Carbon Monoxide Releasing Molecules Rate-Modulated by the Sixth Ligand

A new family of compounds is presented as potential carbon monoxide releasing molecules (CORMs). These compounds, based on tetrachlorocarbonyliridate(III) derivatives, were synthesized and fully characterized by X-ray diffraction, electrospray mass spectrometry, IR. NMR, and density functional theory calculations. The rate of CO release was studied via the myoglobin assay. The results showed that the rate depends on the nature of the sixth ligand, trans to CO, and that a significant modulation on the release rate can be produced by changing the ligand. The reported compounds are soluble in aqueous media, and the rates of CO release are comparable with those for known CORMs, releasing CO at a rate of 0.03-0.58 mu M min(-1) in a 10 mu M solution of myoglobin and 10 mu M of the complexes.

Crystal structure of a soluble decoy receptor IL-22BP bound to interleukin-22

Interleukin-22 (IL-22) plays an important role in the regulation of immune and inflammatory responses in mammals. The IL-22 binding protein (IL-22BP), a soluble receptor that specifically binds IL-22, prevents the IL-22/interleukin-22 receptor 1 (IL-22R1)/interleukin-10 receptor 2 (IL-10R2) complex assembly and blocks IL-22 biological activity. Here we present the crystal structure of the IL-22/IL-22BP complex at 2.75 angstrom resolution. The structure reveals IL-22BP residues critical for IL-22 binding, which were confirmed by site-directed mutagenesis and functional studies. Comparison of IL-22/IL-22BP and IL-22/IL-22R1 crystal structures shows that both receptors display an overlapping IL-22 binding surface, which is consistent with the inhibitory role played by IL-22 binding protein.

Probing conformational changes in orphan nuclear receptor: The NGFI-B intermediate is a partially unfolded dimer

Human nerve growth factor-induced B (NGFI-B) is a member of the NR4A subfamily of orphan nuclear receptors (NRs). Lacking identified ligands, orphan NRs show particular co-regulator proteins binding properties, different from other NRs, and they might have a non-classical quaternary organization. A body of evidence suggests that NRs recognition of and binding to ligands, DNA, homo- and heterodimerization partners and co-regulator proteins involve significant conformational changes of the NR ligand-binding domains (LBDs). To shed light on largely unknown biophysical properties of NGFI-B, here we studied structural organization and unfolding properties of NGFI-B ligand (like)-binding domain induced by chemical perturbation. Our results show that NGFI-B LBD undergoes a two-state guanidine hydrochloride (GndHCl) induced denaturation, as judged by changes in the a-helical content of the protein monitored by circular dichroism spectroscopy (CD). In contrast, changes in the tertiary structure of NGFI-B LBD, reported by intrinsic fluorescence, reveal a clear intermediate state. Additionally, SAXS results demonstrate that the intermediate observed by intrinsic fluorescence is a partially folded homodimeric structure, which further unfolds without dissociation at higher GndHCl concentrations. This partially unfolded dimeric assembly of NGFI-B LBD might resemble an intermediate that this domain access momentarily in the native state upon interactions with functional partners. (C) 2008 Elsevier B.V. All rights reserved.

On the localization of water-soluble porphyrins in micellar systems evaluated by static and time-resolved frequency-domain fluorescence techniques

Fluorescence quenching of meso-tetrakis-4-sulfonatophenyl (TPPS4) and meso-tetrakis-4-N-methylpyridil (TMPyP) porphyrins is studied in aqueous solution and upon addition of micelles of sodium dodecylsulfate (SDS), cetyltrimethylammonium chloride (CTAC), N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and t-octylphenoxypolyethoxyethanol (Triton X-100). Potassium iodide (KI) was used as quencher. Steady-state Stern-Volmer plots were best fitted by a quadratic equation, including dynamic (K-D) and static (K-s) quenching. Ks was significantly smaller than K-D. Frequency-domain fluorescence lifetimes allowed estimating bimolecular quenching constants, k(q). At 25 degrees C, in aqueous solution, TMPyP shows k(q), values a factor of 2-3 higher than the diffusional limit. TPPS4 shows collisional quenching with pH dependent k(q) values. For TMPyP quenching results are consistent with reported binding constants: a significant reduction of quenching takes place for SDS, a moderate reduction is observed for H PS and almost no change is seen for Triton X-100. Similar data were obtained at 50 C. For CTAC-TPPS4 system an enhancement of quenching was observed as compared to pure buffer. This is probably associated to accumulation of iodide at the cationic micellar interface. The attraction between CTAC headgroups and 1(-), and repulsion between SDS and 1(-), enhances and reduces the fluorescence quenching, respectively, of porphyrins located at the micellar interface. The small quenching of TPPS4 in Triton X-100 is consistent with strong binding as reported in the literature. (C) 2008 Elsevier B.V. All rights reserved.

Local influence for Student-t partially linear models

In this paper we extend partial linear models with normal errors to Student-t errors Penalized likelihood equations are applied to derive the maximum likelihood estimates which appear to be robust against outlying observations in the sense of the Mahalanobis distance In order to study the sensitivity of the penalized estimates under some usual perturbation schemes in the model or data the local influence curvatures are derived and some diagnostic graphics are proposed A motivating example preliminary analyzed under normal errors is reanalyzed under Student-t errors The local influence approach is used to compare the sensitivity of the model estimates (C) 2010 Elsevier B V All rights reserved

Synthesis of Phthalocyanines-ALA Conjugates: Water-Soluble Compounds with Low Aggregation

Syntheses of two water-soluble phthalocyanines (Pc) containing 5-aminolevulinic acid (ALA) linked to the core structure are described. These compounds were prepared by using original functionalizations, and they present remarkable structural and photophysical features, indicating that they could be applied to photodynamic therapy (PDT).

Water-soluble Cu, Fe, Mn and Zn species in nuts and seeds

An approach was developed to estimate molecular weight distribution of water-soluble Cu, Fe, Mn and Zn species in Brazil nut, cupuassu seed and coconut pulp by size exclusion chromatography (SEC) coupled on-line to ultra-violet (UV) and off-line to graphite furnace atomic absorption spectrometry (GF-AAS) detectors and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). SEC-UV analytical signals showed the prevalence of high molecular weight (HMW) species (79-1.7 kDa for Brazil nut, 50-1.7 kDa for coconut pulp, and 34-1.7 kDa for cupuassu seeds). The Brazil nut SEC-UV, GF-AAS and MALDI-TOF mass spectra gave confirmation of the association of the elements with water-soluble compounds. The elemental profiles were associated with fractions of compounds of molecular weight 1.2-16 kDa for Brazil nut, 1.7-13 kDa for coconut pulp, and 1.2-7.6 kDa for cupuassu seeds. (C) 2009 Elsevier Inc. All rights reserved.

Sequencing of Spodoptera frugiperda midgut trehalases and demonstration of secretion of soluble trehalase by midgut columnar cells

Both soluble (SfTre1) and membrane-bound (SfTre2) trehalases occur along the midgut of Spodoptera frugiperda larvae. Released SfTre2 was purified as a 67 kDa protein. Its K(m) (1.6 mM) and thermal stability (half life 10 min at 62 degrees C) are different from the previously isolated soluble trehalase (K(m) = 0.47 mM; 100% stable at 62 degrees C). Two cDNAs coding for S. frugiperda trehalases have been cloned using primers based on consensus sequences of trehalases and having as templates a cDNA library prepared from total polyA-containing RNA extracted from midguts. One cDNA codes for a trehalase that has a predicted transmembrane sequence and was defined as SfTre2. The other, after being cloned and expressed, results in a recombinant trehalase with a K(m) value and thermal stability like those of native soluble trehalase. This enzyme was defined as SfTre1 and, after it was used to generate antibodies, it was immunolocalized at the secretory vesicles and at the glycocalyx of columnar cells. Escherichia coli trehalase 3D structure and sequence alignment with SfTre1 support a proposal regarding the residue modulating the pKa value of the proton donor.