RESUMO
The mycelial growth rates in lineal growth assay, yield, and production rate of five Pleurotus ostreatus strains were evaluated in response to different levels of Mn(II) and/or NH4+ in a substrate containing sunflower seed hulls as a main energy and nutritional component. Each strain showed different basal values for mycelial growth rate and biological efficiency on sunflower seed-hull substrate. Adding growth limiting mineral nutrients increased the mycelial growth rate by 13-25%. Primordia initiation for the first flush appeared between day 24 and 28 and days to the second crop ranged from 39 to 51. Biological efficiency increased over control values and reached 60-112%, depending on the strain and the concentration of Mn(II) and NH4+. This study demonstrated the advantage of selecting the most productive P. ostreatus strains in a substrate formulated with sunflower seed hulls to provide the main energy and nutritional ingredients and supplemented with Mn(II) and/or NH4+.
Assuntos
Helianthus/embriologia , Manganês/química , Pleurotus/crescimento & desenvolvimento , Compostos de Amônio Quaternário/química , Sementes/microbiologiaRESUMO
This work provides evidence of a physical instance in which some proteins that are usually inactivated under strong chaotropic conditions may become fully resistant through the occupancy of their binding sites with suitable ligands. In this regard, we found that Moluccella laevis lectin remains stable in the presence of denaturant concentrations of urea when an appropriate saccharide is bound to the protein (Alperin, D.M., Latter, H., Lis, H., and Sharon, N. (1992) Biochem. J. 285, 1-4). Extending this finding, we now demonstrate that the occupancy of the ligand binding sites of concanavalin A (Con A) with appropriate carbohydrates completely prevents the denaturation course elicited by 8 M urea at pH 7.4. In addition, the protecting efficiency of the saccharides was shown to be directly related to their specificities for the lectin. The observed saccharide protection follows the order:methyl alpha-D-mannopyranoside > methyl alpha-D-glucopyr-anoside > mannose > fructose > glucose. Concomitantly, the active tetrameric lectin with a molecular mass of approximately 105 kDa is preserved in 8 M urea when methyl alpha-D-mannopyranoside (100 mM) is present in the medium.