Binding characteristics of bovine serum albumin encapsulated in sol-gel glasses: an alternative for protein interaction studies

Silica glasses doped with 500-700 microg of bovine serum albumin were prepared by the sol-gel method; two pH conditions (pH 5 and 7) were assayed for protein encapsulation. Both biomaterials showed a highly porous structure, with pore sizes in the range 5-28 nm. Columns packed with the ground biogels were on-line coupled to a C18 HPLC column for evaluation of the entrapped protein binding properties using propranolol. Binding capacities (at saturation) were approximately 3.7 and 7.1 microg of propranolol (drug-protein molar ratios 1.4 and 2.7) for the biogels prepared at pH 5 and 7, respectively. The significant difference indicates increased albumin denaturation upon encapsulation at pH 5. A frontal analysis study was then performed in cartridges packed with biogel prepared at pH 7 to evaluate the protein interaction with naproxen at low concentrations (相似文献   

Fe enriched biosolids as fertilizers for orange and peach trees grown in field conditions

Iron enriched biosolids (FEB) from water treatment facilities are being used as an alternative to synthetic chelates in order to improve Fe uptake. The impact of this type of products on iron nutrition is not fully understood. Plant response depends on FEB composition, soil and climatic conditions and crop response. In order to study the effectiveness of FEB as fertilisers, two field experiments have been carried out. Two different commercial formulations of FEB (unmodified u-FEB and modified m-FEB) produced as a by-product of a drinking water treatment facility in Tampa (Florida, USA) were used. An orange tree (Citrus sinensis, cv. Navelina) and a peach tree (Prunus persica cv. Sudanell) field experiments took place in different locations in Spain. Macro and micronutrients were evaluated to assess mineral status of orange and peach leaf samples. Yield and fruit size were also determined. Despite the large amount of Fe bound by the organic matter on FEB, these products were less effective than synthetic chelates to improve iron uptake. No differences were found in orange yield or size. Results show that the ferric treatments improve fruit calibre, but not yield in peaches.     

Differential effects of coinoculations with Pseudomonas jessenii PS06 (a phosphate-solubilizing bacterium) and Mesorhizobium ciceri C-2/2 strains on the growth and seed yield of chickpea under greenhouse and field conditions

In the course of a project carried out in two regions of Spain, Castilla y León and Andalucía, aiming to find useful biofertilizers for staple grain-legumes, an efficient rhizobia nodulating chickpea (termed as C-2/2) and a powerful in vitro phosphate-solubilizing bacterial strain (termed as PS06) were isolated. Analyses of their 16S rDNA sequence indicated that they belong to the bacterial species Mesorhizobium ciceri and Pseudomonas jessenii, respectively. Greenhouse and field experiments were carried out in order to test the effect of single and dual inoculations on chickpea (ecotype ILC-482) growth. Under greenhouse conditions, plants inoculated with Mesorhizobium ciceri C-2/2 alone had the highest shoot dry weight. The inoculation treatment with P. jessenii PS06 yielded a shoot dry weight 14% greater than the uninoculated control treatment, but it was not correlated with shoot P contents. However, the co-inoculation of C-2/2 with PS06 resulted in a decrease in shoot dry weight with respect to the inoculation with C-2/2 alone. Under field conditions, plants inoculated with M. ciceri C-2/2, in single or dual inoculation, produced higher nodule fresh weight, nodule number and shoot N content than the other treatments. Inoculation with P. jessenii PS06 had no significant effect on plant growth. However, the co-inoculation treatment ranked the highest in seed yield (52% greater than the uninoculated control treatment) and nodule fresh weight. These data suggest that P. jessenii PS06 can act synergistically with M. ciceri C-2/2 in promoting chickpea growth. The contrasting results obtained between greenhouse and field experiments are discussed.     

Land use influences harvestman diversity in northern Spain: a case study involving secondary grasslands and forest plantations (Arachnida: Opiliones)

Harvestmen have a general distribution pattern with more species and higher abundance in forests than in open habitats, as previously verified in mountain Cantabrian areas of northern Spain, of the Orocantabrian Province. The study of harvestmen of the low Cantabrian areas of the adjacent biogeographic Cantabro-Atlantic Province is highly appropriate to determine the influence of biogeographic position on the main diversity parameters and the effect of different land uses on harvestman assemblages. The main types of managed habitats (forest plantations and secondary grasslands), together with natural forests, non-planted young forests, shrublands and habitat boundaries were continuously sampled with seven pitfall traps during 1 year at 28 sites. The harvestman assemblages were classified using six different analyses, and indicator species were identified. The spatial patterns of harvestman diversity in low areas differed from those of mountain areas, although they have 15 species in common. Remarkably, higher average harvestman species richness was measured in low Cantabrian areas than in mountain areas. Shrublands and boundaries were the most species-rich habitats. Forested areas were the poorest in abundance, and were not the habitats richest in harvestman species, though they had higher average richness than mountain Cantabrian forests. Grasslands had a unique harvestman composition with significant extraordinary abundances, in particular of Homalenotus quadridentatus (indicator species of this habitat) and H. laranderas. Interestingly, H. laranderas, Paroligolophus agrestis and Ischyropsalis hispanica, indicator species of some open habitats in low Cantabrian areas, have recently been shown to be indicators of shady forests in mountain Cantabrian territories.     

Distinct regulation of pHin and [Ca2+]in in human melanoma cells with different metastatic potential

We investigated whether alterations in the mechanisms involved in intracellular pH (pHⁱⁿ) and intracellular calcium ([Ca²⁺]ⁱⁿ) homeostasis are associated with the metastatic potential of poorly (A375P) and highly (C8161) metastatic human melanoma cells. We monitored pHⁱⁿ and [Ca²⁺]ⁱⁿ simultaneously, using the fluorescence of SNARF-1 and Fura-2, respectively. Our results indicated that steady-state pHⁱⁿ and [Ca²⁺]ⁱⁿ between these cell types were not significantly different. Treatment of cells with NH₄Cl resulted in larger pHⁱⁿ increases in highly than in poorly metastatic cells, suggesting that C8161 cells have a lower H⁺ buffering capacity than A375P. NH₄Cl treatment also increased [Ca²⁺]ⁱⁿ only in C8161 cells. To determine if the changes in [Ca²⁺]ⁱⁿ triggered by NH₄Cl treatment were due to alterations in either H⁺- or Ca²⁺-buffering capacity, cells were treated with the Ca²⁺-ionophore 4Br-A23187, to alter [Ca²⁺]ⁱⁿ. The magnitude of the ionophore-induced [Ca²⁺]ⁱⁿ increase was slightly greater in C8161 cells than in A375P. Moreover, A375P cells recover from the ionophore-induced [Ca²⁺]ⁱⁿ load, whereas C8161 cells did not, suggesting that A375P may exhibit distinct [Ca²⁺]ⁱⁿ regulatory mechanisms than C8161 cells, to recover from Ca²⁺ loads. Removal of extracellular Ca²⁺ ([Ca²⁺]^ex) decreased [Ca²⁺]ⁱⁿ in both cell types at the same extent. Ionophore treatment in the absence of [Ca²⁺]^ex transiently increased [Ca²⁺]ⁱⁿ in C8161, but not in A375P cells. Endoplasmic reticulum (ER) Ca²⁺-ATPase inhibitors such as cyclopiazonic acid (CPA) and thapsigargin (TG) increased steady-state [Ca²⁺]ⁱⁿ only in C8161 cells. Together, these data suggest that the contribution of intracellular Ca²⁺ stores for [Ca²⁺]ⁱⁿ homeostasis is greater in highly than in poorly metastatic cells. Bafilomycin treatment, to inhibit V-type H⁺-ATPases, corroborated our previous results that V-H⁺-ATPases are functionally expressed at the plasma membranes of highly metastatic, but not in poorly metastatic cells in and [Ca²⁺]ⁱⁿ regulatory mechanisms are present in poorly and highly metastatic human melanoma cells. J. Cell. Physiol. 176:196–205, 1998. © 1998 Wiley-Liss, Inc.     

Enhancement of the inhibitory effect of an IL‐15 antagonist peptide by alanine scanning

IL‐15 is a proinflammatory cytokine that acts early in the inflammatory response and has been associated with several autoimmune diseases including rheumatoid arthritis, where it had been proposed as a therapeutic target. We recently reported an IL‐15 antagonist peptide corresponding to sequence 36–45 of IL‐15 (KVTAMKCFLL) named P8, which specifically binds to IL‐15Rα and inhibits IL‐15 biological activity with a half maximal inhibitory concentration (IC50) of 130 µ m in CTLL‐2 proliferation assay. In order to improve binding of peptide P8 to the receptor IL‐15Rα, we used an Ala scan strategy to study contribution of each individual amino acid to the peptide's antagonist effect. Here, we found that Phe and Cys are important for peptide binding to IL‐15Rα. We also investigated other single site mutations and replaced the second Lys in the sequence by the polar non‐charged amino acid threonine. The resulting peptide [K6T]P8 exhibited a higher activity than P8 with an IC50 of 24 µm . We also found that this peptide was more active than peptide P8 in the inhibition of TNFα secretion by synovial cells from rheumatoid arthritis patients. The peptide [K6T]P8 described in this work is a new type of IL‐15 antagonist and constitutes a potential therapeutic agent for rheumatoid arthritis. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.