Solubilization of fish proteins using immobilized microbial cells.

Cells of Bacillus megaterium, Aeromonas hydrophila, and Pseudomonas marinoglutinosa were immobilized in calcium alginate. The immobilized cells secreted protease when held in fish meat suspension in water. The enzyme synthesis by the entrapped cells was supported by small amounts of soluble nutrients present in the meat. The secreted protease solubilized the fish meat, solubilization being optimum at pH range of 7.5 to 9.5 and at 50 degrees C. Under these conditions immobilized B. megaterium was most efficient giving 30% solubilization of the meat, followed by A. hydrophila (18%), while immobilized P. marinoglutinosa was less effective. The optimum ratio of fish meat to beads was about 4:3 for B. megaterium and A. hydrophila. The beads had a storage life of 30 days at 4 degrees C. The results suggested potential for use of immobilized microbial cells having extracellular protease activity to enhance solubility of waste proteins. A prototype reactor with beads holding assembly was fabricated which could recover the beads from the meat slurry after the treatment.

Modification of L-asparaginase from Erwinia carotovora using human serum albumin.

L-Asparaginase from Erwinia carotovora was modified by coupling with human serum albumin. The complex retained 80% of the activity, shifted the pH optima to 7.0, and lowered the Km value by tenfold, but the temperature optima remained at 37 degrees C. It was also found to be heat-resistant.

Biological activities of lipid A from Vibrio parahaemolyticus: stimulation of murine peritoneal macrophages.

The toxicity and macrophage stimulating property of Vibrio parahaemolyticus lipid A was studied. The LD50 dose of lipid A in galactosamine-sensitized mice was found to be 0.6 micrograms when injected intraperitoneally. Administration of lipid A resulted in stimulation of peritoneal macrophages as evident by increase in their cellular RNA contents and lysosomal enzyme activities. The treatment also caused enhancement in the phagocytic activity of macrophages.

Antitumor activity of lipopolysaccharide and radio-detoxified lipopolysaccharide of Vibrio parahaemolyticus.

The antitumor activity of lipopolysaccharide (LPS) and radio-detoxified LPS of Vibrio parahaemolyticus was tested against S180 cells in Swiss mice. The toxicity of the LPS was 200 times less than that of Salmonella typhimurium LPS. The V. parahaemolyticus LPS could be detoxified by exposure to gamma radiation. Both LPS and the irradiated LPS exhibited antitumor activity, though the irradiated LPS was less effective than the native LPS. These observations indicated that exposure to gamma radiation caused significant detoxification of V. parahaemolyticus LPS and the detoxified LPS still possessed considerable antitumor activity.

Stimulation of macrophages by lipopolysaccharide of Vibrio parahaemolyticus.

The effect of lipopolysaccharide (LPS) from Vibrio parahaemolyticus on the biochemical and phagocytic activities of murine peritoneal macrophages was determined. Intraperitoneal treatment with different doses (0.5-25 micrograms) of V. parahaemolyticus LPS markedly increased the cellular RNA content as well as lysosomal enzyme activities of peritoneal macrophages. The treatment also stimulated the phagocytic activities of macrophages. These observations suggest that V. parahaemolyticus LPS causes stimulation of murine peritoneal macrophages.

Stimulation of macrophages and antitumor activity of radiodetoxified endotoxin.

Lipopolysaccharide of Salmonella typhimurium was irradiated with gamma radiation at 10, 15, and 30 kGy doses. A dose of 30 kGy significantly detoxified the LPS (180 times). Mice were injected intraperitoneally with the radiodetoxified LPS, and it was found that it stimulated peritoneal macrophages as was evident from the enhancement of their acid hydrolases and cellular RNA content. Both LPS and radiodetoxified LPS exhibited antitumor activity against S180 cells in Swiss mice. Treatment with 20 micrograms/mouse of either LPS or 30 kGy LPS gave maximum survival of the mice (90%). These mice were found to resist the challenge of S180 cells (1 X 10(6)).

Radicidation for Elimination of Salmonellae in Frog Legs.

The D10 values of three Salmonella spp. often encountered in frog legs, i.e., S. typhimurium , S. enteritidis and S. newport , were found to be between 18 to 30 krad when cells were irradiated at 0-2°C in 0.1 M phosphate buffer, pH 7.0. The radiation sensitivities of these Salmonella spp. increased only marginally when cells were irradiated in frog leg homogenate. The doses of radiation required for eradication of this pathogen in fresh and frozen frog legs were 300 and 400 krad, respectively.

Induction of resistance to ascites tumor in mice with MFS-180 cells treated with glutaraldehyde, lipopolysaccharide, and concanavalin A.

Immunization with MFS-180 vaccine prepared in the presence of glutaraldehyde (0.05%), lipopolysaccharide (LPS) (100 micrograms/ml), and concanavalin A (Con A) (200 micrograms/ml) could protect Swiss mice against a subsequent challenge by 1 X 10(6) MFS-180 cells. The sequence of attachment of LPS and Con A to glutaraldehyde-treated cells as found to determine the efficacy of the vaccine. LPS coupled with glutaraldehyde-treated cells before Con A could effect 100% survival, while LPS attached after Con A treatment to glutaraldehyde-treated cells showed only 60% survival. The protection was specific for syngeneic cells.

Radiation induced alterations in the endotoxin of S. typhimurium.

The lipopolysaccharide (LPS) of S. typhimurium has been shown to be significantly detoxified after in vivo irradiation at 500 krad. Radiation is thus a useful method for converting endotoxin into toxoid. The structural alterations in the detoxified LPS are shown to be mainly in the lipid A molecule, resulting in the loss of beta-hydroxymyristic acid.

Radiovaccine of S. typhimurium cells.

Gamma-irradiation of S. typhimurium cells up to a dose of 500 krad significantly reduces their toxicity. However, the antigenicity of these cells is not altered, which suggests that these cells could be used as a vaccine. The protection offered by the irradiated cells is comparable to that of formalin-treated cells. The radio-vaccine, however, offers an additional advantage of significant detoxification of the endotoxin, thereby minimizing side effects. The lipopolysaccharide extracted from the irradiated S. typhimurium cells offered cross-protection against other Salmonella species tested.