A novel method for the isolation and purification of protoplasts from friable,embryogenic corn (Zea Mays L.) callus

A method is described for the isolation of protoplasts from rapidly-growing, friable embryogenic and organogenic cell cultures of corn. A Sepharose 6MB cyanogen-bromide-activated macrobead column coupled with Cellulase RS was used to separate contaminating cells from protoplasts. The column consists of layering 1.5 cm of the coupled-macrobeads into a 2.2-cm diameter column. Contamination of protoplasts by cells possessing partial or complete walls was reduced from 25% to near zero after a single passage through the column. The column was capable of retaining in excess of 30 million cells and recovering 99% cell-free preparations from culture material consisting of less than 1% protoplasts. Coupled-macrobeads were easily recovered, washed free of cells and stored for repeated use. Corn protoplasts appeared undamaged by the column and rapeseed (Brassica napus) protoplasts which were passed through the column have divided and formed colonies in culture. Uncoupled macrobeads were not as efficient as coupled macrobeads in reducing cellular contamination.     

Rheological characterization of neutral and anionic polysaccharides with reduced mucociliary transport rates

The purpose of this research was to compare the viscoelastic properties of several neutral and anionic polysaccharide polymers with their mucociliary transport rates (MTR) across explants of ciliated bovine tracheal tissue to identify rheologic parameters capable of predicting the extent of reduction in mucociliary transport. The viscoelastic properties of the polymer gels and gels mixed with mucus were quantified using controlled stress rheometry. In general, the anionic polysaccharides were more efficient at decreasing the mucociliary transport rate than were the neutral polymers, and a concentration threshold, where no further decreases in mucociliary transport occurred with increasing polymer concentration, was observed for several of the neutral polysaccharides. No single rheologic parameter (ν, G′, G″, tan δ, G^*) was a good predictor of the extent of mucociliary transport reduction, but a combination of the apparent viscosity (ν), tangent to the phase angle (tan δ), and complex modulus (G^*) was found to be useful in the identification of formulations capable of decreasing MTR. The relative values of each of the rheologic parameters were unique for each polymer, yet once the relationships between the rheologic parameters and mucociliary transport rate reduction were determined, formulations capable of resisting mucociliary clearance could be rapidly optimized. Published: April 20, 2007     

The applicability of an amidated polysaccharide hydrogel as a cartilage substitute: structural and rheological characterization

An amidic derivative of a carboxymethylcellulose-based hydrogel was obtained and characterized in terms of amidation degree. NMR studies and FT-IR imaging spectroscopy demonstrated that the reaction allowed a polymer to be obtained that was characterized by a regular distribution of amidic groups along the polysaccharide chains. Through this regularity, a homogenous three-dimensional scaffold was obtained, which maintained the thixotropic property of the linear polysaccharide.     

Seed treatment technology: An attractive delivery system for controlling root parasitic weed Striga with mycoherbicide

Coating sorghum seeds with Fusarium oxysporum (Foxy 2) for control of the root parasitic weed Striga, appears to be an attractive option for minimizing the inoculum amount, establishing the biocontrol agent in the potential infection zone of the host plants, and offering a simple, easy and economical delivery system. Our investigations resulted in the selection of appropriate seed coating materials and a suitable type and form of fungal inoculum. The coating materials tested were arabic gum (AG10%, 20%, 40%), carboxymethylcellulose (CMC1%, 2%) and pectin (LS 440, LM-5 CS) 1%, while the fungal inoculum included microconidia and fresh and dried chlamydospores produced using different substrates. Foxy 2 survived the seed treatment processing and showed excellent viability on seeds for at least 8 months of storage after coating. In general, the performance of 40% arabic gum in combination with dried chlamydospores was the best among the other types of inoculum and coating material tested. Regardless of the type and form of inoculum and coating materials tested, Foxy 2 was able to colonize all roots, even root tips and hairs of the host (sorghum), thereby meeting important criteria of a promising candidate for controlling Striga when applied as a seed treatment. The efficacy of treated sorghum seed with Foxy 2 using different coating materials in reducing S. hermonthica infestation was evaluated in pot and root chamber trials. Foxy 2 markedly reduced Striga emergence and dry weight and increased the percentage of the diseased emerged Striga shoots. However, the efficacy of seed coating varied according to the type and form of fungal inoculum as well as coating material. Coating sorghum seed with dried chlamydospore inoculum homogenized into 20% arabic gum (as adhesive) showed the highest efficacy of 81 and 77% (i.e., percent reduction in healthy emerged Striga shoots compared to the control treatment) against Striga using either sterilized or non-sterilized soil, respectively. In root chamber bioassays, the application of Foxy 2 in combination with AG40% significantly caused disease in 77% of the germinated Striga seeds and in all tubercles after 25 days of sowing. These findings provide an optimized coating protocol as an attractive delivery system for bioherbicides for root parasitic weeds.     

Decomposition of sugarcane bagasse with lignocellulose-derived thermotolerant and thermoresistant Penicillia and Aspergilli

To promote the decomposition of sugarcane bagasse (SCB) for conversion into value-added products and to reduce waste, the capability of fungal mixes (FMs) to degrade SCB was examined. A total of 169 isolates from SCB and non-SCB were categorized as thermotolerant and thermoresistant. Thirty-six fungal candidates were screened for the presence of polyphenol oxidase, endoglucanase (EDN) and xylanase (XLN) activities, and EDN and XLN activities were quantitated. Five identified isolates (Aspergillus flavus AG10; Aspergillus niger AG68 & NB23; and Penicillium citrinum AG93 & AG140) were selected as the best enzyme producers, and 15 moderately to highly xylolytic, cellulolytic and ligninolytic isolates were added to construct FMs. Using a Taguchi design, the top ten reducing sugar-producing FMs (no. 12 showed the maximum amount of reducing sugar, at 2.11 mg g⁻¹, followed by no. 7, 15, 2, 16, 11, 13, 6, 4, & 8) were selected as potential agents for decomposition durations of 1, 2 and 3 months. The maximum decrease in SCB materials compared with the control was generated by FM 6 (9.08% cellulose reduction); FM 13 (21.03% hemicellulose reduction); and FM 16 (9.21% lignin reduction). These results indicate the potential use of SCB as a substrate for synergistic FMs. These FMs could be applied to the large-scale composting of SCB and other related agricultural residues, thus improving the biological pretreatment of lignocellulose.     

Mechanism of interferon action: stability and translation of simian virus-40 early mRNA coding for T-antigen is comparable in untreated and interferon-treated monkey cells

The effect of interferon treatment on the translation and the stability of simian virus 40 (SV40) early mRNA coding for T-antigen was examined in tsA-infected monkey kidney BSC-1 cells at 40°. Neither the translation nor the stability of SV40 early mRNA was altered by interferon under cellular conditions where the synthesis of reovirus polypeptides was significantly inhibited by interferon. SV40 early mRNA decayed with a half-life of about 3 hours as measured by T-antigen synthesis; the decay rate was indistinguishable between untreated and interferon-treated cells.     

Graft copolymerization of N-vinylformamide onto sodium carboxymethylcellulose and study of its swelling, metal ion sorption and flocculation behaviour

The present paper reports the graft copolymerization of N-vinylformamide onto sodium carboxymethylcellulose by free radical polymerization using potassium peroxymonosulphate/thiourea redox system in an inert atmosphere. The reaction conditions for maximum grafting have been optimized by varying the reaction variables, including the concentration of N-vinylformamide (12.0 × 10⁻²–28.0 × 10⁻² mol dm⁻³), potassium peroxymonosulphate (4.0 × 10⁻³–12.0 × 10⁻³ mol dm⁻³), thiourea (1.2 × 10⁻³–4.4 × 10⁻³ mol dm⁻³), sulphuric acid (2.0 × 10⁻³–10.0 × 10⁻³ mol dm⁻³), sodium carboxymethylcellulose (0.2–1.8 g dm⁻³) along with time duration (60–180 min) and temperature (25–45° C). Water swelling capacity, metal ion sorption and flocculation studies of synthesized graft copolymer have been performed with respect to the parent polymer. The graft copolymer has been characterized by FTIR spectroscopy and thermogravimetric analysis.     

Isolation,characterization and opiate activity of β-endorphin from human pituitary glands

The isolation of a 31-amino acid peptide from human pituitary glands has been described. Its amino acid sequence has been proposed to be identical to the sequence of the carboxyl-terminal 31 amino acids of human β-lipotropin. The peptide, designated as β_h-endorphin, possesses significant opiate activity.     

Polyion-counterion interaction behavior for sodium carboxymethylcellulose in methanol-water mixed solvent media

Precise measurements on the electrical conductivities have been reported for solutions of sodium carboxymethylcellulose in methanol-water mixed solvent media. The conductivity vs. concentration data have been analyzed on the basis of the scaling theory approach for semidilute polyelectrolyte conductivity. The effects of the temperature, the medium, and the polymer concentration on the fractions of uncondensed counterions, the polyion conductivities, the standard state free energies of counterion association, and the coefficients of friction between the polyion and the solvent have also been investigated and the results have been interpreted from the viewpoints of polyion-countreion interactions, effective charge on the polyion, solvation of counterions and the polyionic sites, and counterion dissociation.