It was found that K99 pili from enterotoxigenic Escherichia coli (of bovine origin) could be extracted by treatment with 3M-KSCN solution. The K99 pili were purified by preparative isoelectric focusing to apparent homogeneity as judged by the presence of a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; the molecular weight of this component was calculated to be 12 60...

This paper reports the first Raman spectroscopic study of the potassium complex of the cation-specific antibiotic valinomyoin. Complete Raman spectra (140 to 3000 cm-l) of crystalline valinomycin-KSCN and its Ccl,, CHCl, and CaHSOH solutions are presented and used to probe the structure of the complex in these environments. In all oases a single, narrow peak is observed in the ester C=O stretch...

The rate of regeneration of reduced RNase by glutathione was examined in the presence of several added substances: substrate, phospholipid, other proteins, bacterial ribosomes, and neutral salts. Of these, only neutral salts showed substantial effects. K2HOP4 and (NH4)2SO4 strongly accelerated regeneration, the alkali chlorides showed moderate acceleration or inhibition, while LiBr and KSCN str...

The hepatitis B surface antigen (HBsAg) is a recombinant protein-based vaccine being able to form virus-like particles (VLPs). HBsAg is mainly produced using yeast-based expression systems, however, recent results strongly suggest that VLPs are not formed within the yeast cells during the cultivation but are formed in a gradual manner during the following down-stream procedures. VLPs are also n...

To probe the macromolecular structure of the scrapie agent and explore conditions for monomerization, the stability of the agent in low concentrations of inorganic ions was determined. A reduction by a factor of 10(5) in scrapie titer was found on exposure of the agent to 1 M KSCN or 0.3 M NaOH. In addition to the inactivation by thiocyanate ions, other chaotropic ions such as guanidinium and t...

We describe the avidity maturation of IgGs in human toxoplasmosis using sequential serum samples from accidental and natural infections. In accidental cases, avidity increased continuously throughout infection while naturally infected patients showed a different profile. Twenty-five percent of sera from chronic patients having specific IgM positive results could be appropriately classified usin...

The efficacy and selectivity of chaotropic and phase-partitioning procedures for the extraction of membrane proteins from Brucella ovis were compared with a standard Sarkosyl method. Major group 1, 2 and 3 outermembrane proteins (OMPs) of B. ouis stained by Coomassie blue in SDS-PAGE gels had, respectively, apparent molecular masses of 81/82 kDa, 39-41 kDa and 3&32 kDa. The presence of these ba...

BACKGROUND Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba...