Using free radical polymerization and Mannich reaction, synthesis and characterization of cationic polyacrylamides having similar molecular weight but different charge densities

Using free radical solution polymerization technique and Mannich reaction, five different polyacrylamides with similar molecular weight but variable charge densities were synthesized. High molecular weight polyacrylamides were synthesized using potassium persulfate and N,N,N',N'-tetramethylethylenediamine system as initiators. This was achieved by increasing the concentration of acrylamide monomer. They were then characterized by infrared spectroscopy, viscosity measurements and glass transition temperature measurement. These compounds with various cationic charge densities from 48.2, 161.7, 355, 425 and 485 C/g were prepared through Mannich reaction. The results indicate, by increasing the acidity of the polyacrylamide solution using sulfuric acid, the pH of the polyacrylamide solution decreases correspondingly. As a result, the positive charges increased resulting in the enrichment of charge densities.

Protein diffusion through charged nanopores with different radii at low ionic strength

Pore permeability for two similar molecular weight proteins (BSA and BHb) through nanoporous charged membranes at low ionic strength (I = 0.001 M).

Trypsin inhibitors in turnip (Brassica rapa L.) seeds

A method of trypsin inhibitors isolation from turnip seeds is described. Inhibitors were extracted with 0.01 N HCI, concentrated by salting out with ammonium sulfate, and purified using ion-exchange chromatography on Sp-Sephadex C-25, QAE-Sephadex A-25 and affinity chromatography on immobilized trypsin. Among the three isolated inhibitors, ITR I of molecular weight 15.9 kDa, pl. 6,4, inhibited trypsin activity only. Inhibitors ITR II and ITR Ill inhibited also chymotrypsin activity, they had similar molecular weight (about 10 kDa), but their pI is 7.5 and over 10, respectively. Arginine residue occurred in P, position of the reactive site of inhibitors ITR I and ITR III, while in ITR 11 this position was occupied by lysine residue. Electrophoresis on polyacrylamide gel revealed that each inhibitor possessed two protein fractions, probably a virgin and modified form, with the reactive site peptide bond broken by trypsin.

Preparation of Three Dimensional Products Using Flow Deformability of Wood Treated by Small Molecular Resins

To investigate the effect of the additive agents such as polyethylene glycols (PEGs), melamine formaldehyde resin (MF-resin) and phenol formaldehyde resin (PF-resin) on the flow deformability of solid wood, free compression tests during heating were performed. Various molecular weights ranging from 200 to 20,000 for PEGs and almost similar molecular weight around 380 for MF-resin and PF-resin were applied. It was found from the compression tests that the yield stress indicating wood cell deformation resistance was drastically decreased with smaller molecular PEGs in wood, whereas the initiation of flow behavior, which is derived from detachment/slippage between cells, occurred at lower pressure with larger molecular PEGs. For generating the flow behaviors of solid wood, smaller molecular resin/substance was not always suitable. Thermosetting agents also act as a plasticizer during heating and especially the PF-resin showed better softening effect as well as a promoter of flow behavior than the MF-resin with almost similar molecular weight. This indicates that it is important for generating flow behavior to consider affinity/compatibility of resin to wood constituents. A maximum flow deformation ratio in the tangential direction of wood reached 180 % when using PEG 20,000 and MF-resin as an additive agent. It was also demonstrated that using PF-resin and MF-resin deep cup products shaped by a backward extrusion process had a better size stability against water, steam, and acetone.

Purification and Characterization of Alkaline Polygalacturonases Produced by Paenibacillus polymyxa 20185 in Submerged Cultures

Two extracellular alkaline polygalacturonases from extracts of liquid cultures of Paenibacillus polymyxa 20185 were purified by gel filtration chromatography to homogeneity as judged by SDS-PAGE. The purified alkaline polygalacturonases (PG1 and PG2) had a similar molecular weight of 65 kDa, exhibited maximal activity at 50°C with pH 10.0, and were stable in alkaline conditions. The purified alkaline polygalacturonases activities were enhanced in the presence of Mg2+, and were resistant to inhibition by Mn2+, Zn2+and Cu2+. Michaelis-menten constants of PG1 and PG2 were found as 3.6mg/mL and 3.5mg/mL, respectively.

The Role of Different Hyaluronic Acids in the Articular Cartilage of Rabbit

Purpose: To elucidate if the differences found in the physico-chemical and rheological behaviour of Hyaluronic Acids result in different in vivo activity. For this purpose two Hyaluronic Acids (HA), HA-1 and HA-2, with similar molecular weight but different percentage of concentration variation, were compared through an osteoarthritis model. Methods and Materials: Osteoarthritis was induced in white New Zealand rabbits by anterior cruciate ligament section. After the induction period, the animals were allocated to receive HA-1 or HA-2 intra-articularly in one knee whereas the contralateral knee was used as Operated Control. An additional group of non-operated animals was used as Healthy Controls. Samples of cartilage were taken for different measures: apoptosis, nitric oxide (nitrites) and hyaluronic acid in synovial fluid. Results: The administration of HA-1 had a significant inhibitor effect on apoptosis of the chondrocytes compared to operated untreated animals (p = 0.0089), whereas this difference was not observed in the HA-2 knees. Levels of nitrites determined by HPLC in the HA-1 knees were similar to those in the Healthy group (p = 0.6551) whereas they were significantly higher in Operated Control and HA-2 groups (p = 0.0001). The comparison between HA-1 and HA-2 also revealed significantly lower levels of nitrites in the HA-1 knees (p = 0.0001). Values of hyaluronic acid in synovial fluid did not show statistical differences between the different study groups. Conclusions: HA-1 and HA-2 showed different physico-chemical characteristics and these differences have resulted in different in vivo behaviour. As a consequence, not all the HA with similar molecular weight can be considered as equivalent.

A MvaI PCR-RFLP detecting a silent allele at the goat α-lactalbumin locus

Alpha-lactalbumin (α-la), a calcium metalloprotein, is one of the major serum-proteins in ruminant milk (Jenness, 1982) and induces lactose synthesis in the mammary gland by interacting with the enzyme UDP-galactosyltransferase, giving rise to the heterodimer enzyme lactose synthase (Ebner & Brodbeck, 1968; Kuhn, 1983). The goat α-la transcription unit (LALBA), located on chromosome 5 (Hayes et al. 1993), is organized in 4 exons varying in length from 75 nucleotides (3rd exon) to 329 nucleotides (4th exon) coding for a 123-amino acid polypeptide chain (Vilotte et al. 1991). According to the strong similarity between bovine α-la (Vilotte et al. 1987) and human lysozyme (similar molecular weight, the same number of S-S bonds, identical N and C terminal residues; Peters et al. 1989), it has been proposed that both genes arose from a common ancestor (Vilotte et al. 1991).

Introduction of a norA Promoter Region Mutation into the Chromosome of a Fluoroquinolone-Susceptible Strain ofStaphylococcus aureus Using Plasmid Integration

ABSTRACT It has been postulated that a mutation 11 bp 3′ to the −10 motif of the norA promoter is involved in the increased expression of the gene observed in some strains of Staphylococcus aureus exhibiting efflux-related fluoroquinolone resistance. Introduction of this mutation into the chromosome of a fluoroquinolone-susceptible strain by plasmid integration resulted in the minimum inhibitory concentrations of NorA substrates being increased, fluoroquinolone uptake being reduced, and norAexpression being enhanced. Diffuse hybridization of norAand integrating vector probes at a similar molecular weight range, higher than that of the norA transcript, was observed in the integrant, suggesting the possibility of a plasmid-based promoter contributing to norA expression. The ratio of the quantity of this transcript, which was also observed in the parent strain of the integrant, to the quantity of primary norA transcript was 0.14, demonstrating that it was unlikely that this mRNA species contributed significantly to the results observed. It is more likely that the introduced promoter region mutation does affect the expression of norA.

The BiP protein and the endoplasmic reticulum of Schizosaccharomyces pombe: fate of the nuclear envelope during cell division

A polyclonal antibody was raised to the C-terminal region of fission yeast BiP. The use of this antibody for immunoprecipitation, western blotting and immunofluorescence has confirmed and extended the observations made previously with an epitope-tagged BiP molecule. A fraction of BiP protein is glycosylated in Schizosaccharomyces pombe cells. Pulse-chase experiments showed that this modification occurs rapidly upon synthesis and that the extent of glycosylation does not then change with time. BiP protein is induced by elevated temperatures and by treatment with tunicamycin. The antibody cross-reacts with proteins of similar molecular weight in the yeasts Kluyveromyces lactis and Schizosaccharomyces japonicus. Immunofluorescence of BiP has been used to follow the behaviour of the ER and in particular the nuclear envelope through the cell cycle.