Molecular identification of four different alpha-amylase inhibitors from baru (Dipteryx alata) seeds with activity toward insect enzymes

The endophytic bruchid pest Callosobruchus maculatus causes severe damage to storage cowpea seeds, leading to economical losses. For this reason the use of alpha-amylase inhibitors to interfere with the pest digestion process has been an interesting alternative to control bruchids. With this aim, alpha-amylase inhibitors from baru seeds (Dipteryx alata) were isolated by affinity chromatographic procedures, causing enhanced inhibition of C. maculatus and Anthonomus grandis alpha-amylases. To attempt further purification, this fraction was applied onto a reversed-phase HPLC column, generating four peaks with remarkable inhibition toward C. maculatus alpha-amylases. SDS-PAGE and MALDI-ToF analysis identified major proteins of approximately 5.0, 11.0, 20.0 and 55 kDa that showed alpha-amylase inhibition. Results of in vivo bioassays using artificial seeds containing 1.0% (w/w) of baru crude extract revealed 40% cowpea weevil larvae mortality. These results provide evidence that several alpha-amylase inhibitors classes, with biotechnological potential, can be isolated from a single plant species.     

Kinetic modeling for the biosorption of copper by pretreated Aspergillus niger biomass

In this present work, a kinetic model for biosorption of copper was developed considering the possibility of different forms of functional groups being present on the surface of the biomass prepared from Aspergillus niger. Results showed that metal uptake by A. niger was a mass transfer driven process, requiring only 30min to achieve 70% adsorption efficiency. Copper sorption by A. niger was influenced by the biomass dose, initial metal ion concentration, and pH of the solution. The Langmuir and Freundlich adsorption isotherms were used to describe the behavior of the system at different pH. The retention capacity of the biomass was determined at pH 6.0 to be equal to 23.62mg/g of biomass. The pretreatment with formalin improved the uptake of metal ion.     

The design and preliminary structure-activity relationship studies of benzotriazines as potent inhibitors of Abl and Abl-T315I enzymes

We describe the design, synthesis and structure-activity relationship studies in optimizing a series of benzotriazine compounds as potent inhibitors of both Abl and Abl-T315I enzymes. The design includes targeting of an acid functional residue on the alphaC-helix that is available only upon kinase activation. This designed interaction provides an advantage in overcoming the challenges arising from the T315I mutation of Abl and transforms poor (ca. 10 microM) inhibitors into those with low nM potency.     

Dermatoglyphics of the Ogoni of Nigeria and its historiographic implications

The dermal ridges on the surfaces of the palms and the fingers form dermatoglyphic patterns which are phylogenetically stable traits useful for evaluating interpopulation affinities and distinctiveness. In this study, these traits were investigated according to traditional methods among the Ogoni people of the Niger Delta region of Southern Nigeria, considering the uncertainties surrounding the people's historiography and the paucity of morphologic studies on the tribe. The evidences of finger whorl pattern frequencies, Total Ridge Count and palmar A-B ridge count indicate the close dermatoglyphic resemblance of the Ogoni to tribal populations of southern Ghana. These findings have implications as to the likely provenance of the Ogoni people, providing support to the traditionally view among the people that their ancestors are migrants from some tribe in southern Ghana, West Africa.     

Accessory cell competence of ovine oligodendrocytes in mitogenic activation of human peripheral T cells

The multiple sclerosis (MS) plaque is characterized by mononuclear inflammatory cell infiltration, demyelination, loss of oligodendrocytes (OGC), and proliferation of astrocytes. Although antigen-specific, Ia-dependent cellular immune mechanisms have been sought in plaque pathogenesis, Ia-independent T cell activation has not been actively investigated. We examined a potential role of OGC in accessory cell-dependent T cell mitogenesis with the anti-T3 monoclonal antibody OKT3. OGC isolated from ovine white matter on sucrose density gradients were uniformly negative for esterase activity, unlike ovine monocytes. Purified human T cells did not exhibit significant proliferation in 3-day cultures with OKT3, autologous peripheral blood adherent cells (PBAC), or ovine OGC. When T cells were cultured with either PABC or OGC in the presence of OKT3, brisk mitogenesis was observed. Thus, OGC have the capacity to function as accessory cells in the mitogen-induced proliferation of T cells.     

Use of Horseradish Peroxidase-Labeled Antibody for Light and Electron Microscope Localization of Reovirus Antigen

Horseradish peroxidase-labeled antibody was used for light and electron microscopic localization of reovirus antigen in tissue culture. Reaction product in infected cells was easily detected in the cytoplasm, and the procedure was as sensitive as the fluorescent-antibody technique. At the electron microscopic level, infected and enzyme-labeled antibody-treated cells showed accumulations of reaction product at the sites of viral replication and around the viral particles. Reaction product was not detected in unstained infected cells, in stained uninfected cells, or in cells infected with an unrelated virus.     

Application of lipase to concentrate the docosahexaenoic acid (DHA) fraction of fish oil

A commercial lipase preparation from Rhizopus niveus was used to concentrate the omega-3 fatty acid, docosahexaenoic acid (DHA) component in fish oil. The DHA content of cod-liver oil was 9.64% (w/w) of total fatty acids. Enzymatic digestion conditions were established which produced a DHA content in the monoglycerides fraction of 29.17% (w/w) of total fatty acid, triglyceride, and diglyceride components were 5.72, 9.95, and 15316%, respectively.     

Steroid bioconversion in a microemulsion system

The Delta(1,2)-dehydrogenation of high concentrations of the steroid -methyl-Reichstein's compound S-21-acetate (16MRSA) in a microemulsion system was studied using heat-dried and thawed Arthrobacter simplex cells as biocatalyst. The microemulsion system consists of an organic phase [75-95% (v/v)] with steroid (1-60 g/L(tot)), an aqueous phase [5-25% (v/v)] containing the cells (5-30 g/L(tot)), and a neutral surfactant (5-20 g/L organic solvent). Benzene derivatives, which solubilize 16MRSA up to 94 g/L, and phospholipids were used as organic solvents and surfactants, respectively, and menadione was added as an external electron acceptor. Factors affecting the dehydrogenation rate in the microemulsion system were studied. The influences of the 16MRSA and the menadione concentration on the dehydrogenation rate were described by Michaelis-Menten kinetics, apparent V'(max) and K'(m) values of 2.06 g/g dry weight h and 18.9 g/L for 16MRSA and 4.97 g/g dry weight h and 1.91 g/L for menadione being obtained. Optimal menadione concentration was dependent on the steroid concentration was dependent on the steroid concentration used. The reaction was strongly inhibited by high product concentrations. Much higher activities were obtained with the thawed cells than with the dried cells, conversions of 98% being reached within 14-16 h. for 16MRSA and cell dry weight concentrations of 40 and 10 g/L, respectively. Activity retention in a batch stirred tank reactor remained constant during the first 16-24 h of operation and then decreased, depending on the stirring rate; 22 to 65% of the initial reaction rate was obtained after 48 h at stirring rates of 650 and 2000 rpm, respectively.     

A general method for characterizing naturally occurring folate compounds, illustrated by characterizing Torula yeast (Candida utilis) folates

A method previously found suitable for the chromatographic separation and identification of simpler folates has been extended and found suitable for separating and characterizing all the complex polyglutamyl folyl derivatives occurring naturally. Folates were characterized employing the combined use of analytical DEAE-cellulose chromatography, folylpoly-γ-glutamyl carboxypeptidase digestion, and differential microbiological growth response studies. An observed relation between the log phosphate concentration of the eluting buffer and the number of γ-glutamyl residues in successive pteroylpoly-γ-glutamyl derivatives provides a simple tool for a rapid and accurate identification of folate compounds from their elution profile. Twelve folate compunds present in Torula yeast (Candida utilis) were characterized employing this method; 80% of the total folates appeared to be pteroylpolyglutamates. The method characterizes not only the number of γ-glutamyl residues but also the state of reduction of the pteridine ring and the nature of the 1-C substituents attached.