Operational intensification by direct product sequestration from cell disruptates: application of a pellicular adsorbent in a mechanically integrated disruption-fluidised bed adsorption process

A novel prototype adsorbent, designed for intensified fluidised bed adsorption processes, was assembled by the emulsification coating of 4% (w/v) porous agarose upon a zirconia-silica solid core. The adsorbent, designated ZSA (particle density 1.75 g/ml, maximum pellicle depth 40 microm), was subjected to physical and biochemical comparison with the performance of two commercial adsorbents (Streamline and Macrosorb K4AX). Bed expansion qualities and hydrodynamic characteristics (N, D(axl) and B(o)) of ZSA demonstrated a marked robustness in the face of elevated velocities (up to 550 cm/h) and biomass loading (up to 30% (ww/v)) disrupted yeast cells. Cibracron Blue derivatives of the pellicular prototype (ZSA-CB), evaluated in the batch and fluidised bed recovery of glyceraldehyde 3-phosphate dehydrogenase (G3PDH) from unclarified yeast disruptates, exhibited superior capacities and adsorption/desorption performance to the commercial derivatives. These advanced physical and biochemical properties facilitated a demonstration of the direct, mechanical coupling of bead-milling and fluidised bed adsorption in a fully integrated process for the accelerated recovery of G3PDH from yeast. The generic application of such pellicular adsorbents and integrated processes to the recovery of labile, intracellular products is discussed.     

Uptake and metabolism of epicatechin and its access to the brain after oral ingestion

Epicatechin is a flavan-3-ol that is commonly present in green teas, red wine, cocoa products, and many fruits, such as apples. There is considerable interest in the bioavailability of epicatechin after oral ingestion. In vivo studies have shown that low levels of epicatechin are absorbed and found in the circulation as glucuronides, methylated and sulfated forms. Recent research has demonstrated protective effects of epicatechin and one of its in vivo metabolites, 3′-O-methyl epicatechin, against neuronal cell death induced by oxidative stress. Thus, we are interested in the ability of ingested epicatechin to cross the blood brain barrier and target the brain. Rats were administered 100 mg/kg body weight/d epicatechin orally for 1, 5, and 10 d. Plasma and brain extracts were analyzed by HPLC with photodiode array detection and LC-MS/MS. This study reports the presence of the epicatechin glucuronide and 3′-O-methyl epicatechin glucuronide formed after oral ingestion in the rat brain tissue.     

Vermicomposting of different forms of water hyacinth by the earthworm Eudrilus eugeniae,Kinberg

Six-month long trials were conducted on different vermireactors fed with one of the following forms of water hyacinth: (a) fresh whole plants, (b) dried whole plants, (c) chopped pieces of fresh plants, (d) 'spent' weed taken from reactors after extracting volatile fatty acids (VFAs), (e) precomposted fresh weed and (f) precomposted spent weed. The first four forms were studied with and without cowdung. The experiments revealed three clear trends (i) of the various forms of the weed assessed, the precomposted forms were the most favoured as feed by Eudrilus eugeniae, Kinberg, while the fresh whole form was the least favoured, (ii) the different forms of spent weed were favoured over the corresponding forms of fresh weed, and (iii) blending of cowdung (approximately 14% of the feed mass) with different forms of water hyacinth had a significant positive impact on vermicast output, growth in worm zoomass, and production of offspring relative to the corresponding unblended feed. In all reactors, the 'parent' earthworms steadily grew in size over the six-month span, and produced offspring. There was no mortality. The experiments thus confirm that water hyacinth can be sustainably vermicomposted in any of the forms with E. eugeniae.     

Sulfur containing derivatives from Ferula persica var. latisecta

Two new sulfur containing derivatives, t-butyl 3-[(1-methylpropyl)dithio]-2-propenyl malonate (1), t-butyl 3-[(1-methylthiopropyl)thio]-2-propenyl malonate (2) were isolated from the roots of Ferula persica Willd. var. latisecta D. F. Chamberlain. Their structures were elucidated by spectral methods.     

Percutaneous permeation of enantiomers and racemates of chiral drugs and prediction of their flux ratios using thermal data: a pharmaceutical perspective

Albeit pharmacological, pharmacokinetic, and toxicological differences between enantiomeric pairs or between the pure enantiomers and racemate of chiral drugs are known to exist for decades, we are just beginning to realize that there are apparent differences between these species with respect to their percutaneous permeation as well. Such differences in permeation are likely to be enhanced when chiral drugs are formulated with chiral excipients, necessitating a careful assessment of the effect of formulation excipients on the permeation as well as the overall therapeutic outcomes. The in vitro transport data from the preclinical investigations, using laboratory animal models and/or in vitro cell culture systems, must be carefully validated in vivo as there are differences between these models and the human skin. Mathematical models such as MTMT that utilize the interdependence of certain physicochemical characteristics and percutaneous permeability have a predictive value in assessing the flux behavior of enantiomers and racemates.     

Effects of some flavonoids on the susceptibility of low-density lipoprotein to oxidative modification

The effects of six flavonoids viz., apigenin, genistein, morin, naringin, pelargonidin and quercetin on the susceptibility of low-density lipoprotein (LDL) to oxidative modification were investigated. Flavonoids were added to plasma and incubated for 3 hr at 37 degrees C, and the LDL fraction was separated by ultracentrifugation. Oxidizability of LDL was estimated by measuring conjugated diene (CD), lipid peroxides and thiobarbituric acid-reactive substances (TBARS), after cupric sulfate solution was added. Quercetin and morin significantly (P<0.01 by ANOVA) prolonged the lag time before initiation of oxidation reaction in dose-dependent manner. They also suppressed the formation of lipid peroxides and TBARS more markedly than other flavonoids. The ability to prolong lag time and suppression of lipid peroxides and TBARS formation was in the following order: quercetin >morin >pelargonidin >genistein >naringin >apigenin. LDL exposed to flavonoids reduced oxidizability. These findings suggest that flavonoids may have a role in ameliorating atherosclerosis.     

Dieldrin initiates apoptosis in rat thymocytes

In vitro incubation for 6 hr to pesticide dieldrin resulted in a dose-dependent decrease of cell viability comparable to that of dexamethasone. In vivo experiments also demonstrated that dieldrin administration induced a dose-dependent thymic atrophy which appeared to be mediated by endogenous corticosteroids. Agarose gel electrophorosis analysis, revealed the generation of typical apoptotic oligosomal DNA fragmentation in presence of dieldrin. However, in response to high concentrations of pesticide, cells seemed to undergo necrosis pathway. Thus, it may be concluded that dieldrin induced apoptosis in rat thymocytes.     

Bioconversion of acid- and gamma-ray-treated sweet potato residue to microbial protein by mixed cultures

Sweet potato residue, a starchy agricultural waste, was used as a substrate to produce microbial protein by Fusarium moniliforme and Saccharomyces cerevisiae in submerged fermentation. Acid- and gamma-irradiation-pretreated sweet potato residue enhanced the biomass yield and protein production when the residue was fermented with F. moniliforme and S. cerevisiae. A mixed culture of F. moniliforme and S. cerevisiae efficiently and rapidly utilized free sugars; the maximal biomass yield (13.96 g/l) and protein production (65.8%) were obtained after 3 days fermentation. Lower carbon utilization by the two microbial strains occurred in the waste-containing media as compared to control, increasing the economic value of the waste usage. Received 25 October 2001/ Accepted in revised form 22 June 2002