RESUMEN
Maghemite nanoparticles (MNPs) were functionalized with glycine, by a cost-effective and environmentally friendly procedure, as an alternative route to typical amine-functionalized polymeric coatings, for highly efficient removal of copper ions from water. MNPs were synthesized by co-precipitation method and adsorption of glycine was investigated as a function of ligand concentration and pH. The efficiency of these functionalized nanoparticles for removal of Cu(2+) from water has been explored and showed that adsorption is highly dependent of pH and that it occurs either by forming chelate complexes and/or by electrostatic interaction. The adsorption process, which reaches equilibrium in few minutes and fits a pseudo second-order model, follows the Langmuir adsorption model with a very high maximum adsorption capacity for Cu(2+) of 625mg/g. Furthermore, these nanoadsorbents can be used as highly efficient separable and reusable materials for removal of toxic metal ions.
Asunto(s)
Cobre/aislamiento & purificación , Compuestos Férricos/química , Glicina/química , Nanopartículas del Metal/química , Contaminantes Químicos del Agua/aislamiento & purificación , Aguas Residuales/químicaRESUMEN
A large-scale mapping of the worker honeybee brain proteome was achieved by MudPIT. We identified 2742 proteins from forager and nurse honeybee brain samples; 17% of the total proteins were found to be differentially expressed by spectral count sampling statistics and a G-test. Sequences were compared with the EuKaryotic Orthologous Groups (KOG) catalog set using BLASTX and then categorized into the major KOG categories of most similar sequences. According to this categorization, nurse brain showed increased expression of proteins implicated in translation, ribosomal structure, and biogenesis (14.5%) compared with forager (1.8%). Experienced foragers overexpressed proteins involved in energy production and conversion, showing an extensive difference in this set of proteins (17%) in relation to the nurse subcaste (0.6%). Examples of proteins selectively expressed in each subcaste were analyzed. A comparison between these MudPIT experiments and previous 2-DE experiments revealed nine coincident proteins differentially expressed in both methodologies.
Asunto(s)
Abejas/metabolismo , Encéfalo/metabolismo , Proteínas de Insectos/metabolismo , Proteoma/metabolismo , Animales , Cromatografía Líquida de Alta Presión , Electroforesis en Gel Bidimensional , Expresión Génica , Perfilación de la Expresión Génica , Proteínas de Insectos/genética , Proteínas de Insectos/aislamiento & purificación , Isoformas de Proteínas/química , Isoformas de Proteínas/aislamiento & purificación , Isoformas de Proteínas/metabolismo , Proteoma/genética , Proteoma/aislamiento & purificaciónRESUMEN
BACKGROUND: In the barley malting process, partial hydrolysis of beta-glucans begins with seed germination. However, the endogenous 1,3-1,4-beta-glucanases are heat inactivated, and the remaining high molecular weight beta-glucans may cause severe problems such as increased brewer mash viscosity and turbidity. Increased viscosity impairs pumping and filtration, resulting in lower efficiency, reduced yields of extracts, and lower filtration rates, as well as the appearance of gelatinous precipitates in the finished beer. Therefore, the use of exogenous beta-glucanases to reduce the beta-glucans already present in the malt barley is highly desirable. RESULTS: The zygomycete microfungus Rhizopus microsporus var. microsporus secreted substantial amounts of beta-glucanase in liquid culture medium containing 0.5% chitin. An active protein was isolated by gel filtration and ion exchange chromatographies of the beta-glucanase activity-containing culture supernatant. This isolated protein hydrolyzed 1,3-1,4-beta-glucan (barley beta-glucan), but showed only residual activity against 1,3-beta-glucan (laminarin), or no activity at all against 1,4-beta-glucan (cellulose), indicating that the R. microsporus var. microsporus enzyme is a member of the EC 3.2.1.73 category. The purified protein had a molecular mass of 33.7 kDa, as determined by mass spectrometry. The optimal pH and temperature for hydrolysis of 1,3-1,4-beta-glucan were in the ranges of 4-5, and 50-60 degrees C, respectively. The Km and Vmax values for hydrolysis of beta-glucan at pH 5.0 and 50 degrees C were 22.39 mg.mL-1 and 16.46 mg.min-1, respectively. The purified enzyme was highly sensitive to Cu+2, but showed less or no sensitivity to other divalent ions, and was able to reduce both the viscosity and the filtration time of a sample of brewer mash. In comparison to the values determined for the mash treated with two commercial glucanases, the relative viscosity value for the mash treated with the 1,3-1,4-beta-glucanase produced by R. microsporus var. microsporus. was determined to be consistently lower. CONCLUSION: The zygomycete microfungus R. microsporus var. microsporus produced a 1,3-1,4-beta-D-glucan 4-glucanhydrolase (EC 3.2.1.73) which is able to hydrolyze beta-D-glucan that contains both the 1,3- and 1,4-bonds (barley beta-glucans). Its molecular mass was 33.7 kDa. Maximum activity was detected at pH values in the range of 4-5, and temperatures in the range of 50-60 degrees C. The enzyme was able to reduce both the viscosity of the brewer mash and the filtration time, indicating its potential value for the brewing industry.
Asunto(s)
Cerveza , Glicósido Hidrolasas/aislamiento & purificación , Rhizopus/enzimología , Rhizopus/aislamiento & purificación , Industria de Alimentos/métodos , Industria de Alimentos/tendencias , Glicósido Hidrolasas/metabolismo , Hordeum/enzimología , beta-Glucanos/metabolismoRESUMEN
The primary structure of cangitoxin (CGX), a 4958 Da peptide from the sea anemone Bunodosoma cangicum, was determined: GVACRCDSDGPTVRGNSLSGTLWLTGGCPSGWHNCRGSGPFIGYCCKK. CGX contains all the 11 residues that are conserved and the 5 that are conservatively substituted within or between the type 1 and type 2 sequences of sea anemone peptides with specific action on voltage-sensitive sodium channels. Furthermore, it also has 6 identities (Asp9, Arg14, Asn16, Leu18, Trp33 and Lys48) and 1 homology (Arg36) in the 8 residues of the pharmacophore of the sea anemone ApB which are essential for interaction with mammalian sodium channels. The intrahippocampal injection of CGX induces several sequential behavioral alterations--episodes of akinesia alternating with facial automatisms and head tremor, salivation, rearing, jumping, barrel-rolling, wet dog shakes and forelimb clonic movements--and the electroencephalography analysis shows that they were followed by important seizure periods that gradually evolved to status epilepticus that lasted 8-12 h, similar to that observed in the acute phase of the pilocarpine model of epilepsy. These results suggest that CGX may be an important tool to develop a new experimental model of status epilepticus which may contribute to understanding the etiology of epilepsy and to test the effects of new antiepileptic drugs.
Asunto(s)
Conducta Animal/efectos de los fármacos , Venenos de Cnidarios/química , Venenos de Cnidarios/toxicidad , Electroencefalografía/efectos de los fármacos , Convulsiones/inducido químicamente , Secuencia de Aminoácidos , Animales , Masculino , Datos de Secuencia Molecular , Ratas , Ratas Wistar , Anémonas de Mar , Homología de Secuencia de AminoácidoRESUMEN
Enterolobin is a plant cytolytic protein similar to the bacterial cytolysin aerolysin. Biochemical and biophysical techniques were used to verify if enterolobin, like aerolysin, adopts a dimeric structure in solution. SDS-PAGE showed bands corresponding to enterolobin monomer, dimer and oligomers, whilst gel filtration chromatography and electrospray mass spectrometry revealed preferred association of enterolobin as a dimer. Atomic force microscopy (AFM) of enterolobin showed images of a dimer assembly at a concentration as low as 10 microg/ml, similarly to aerolysin. The enterolobin in silico docked structure is coherent with AFM enterolobin dimer shapes.