Induction of delayed-type hypersensitivity by the T cell line specific to bacterial peptidoglycans

A T cell line specific for the chemically well-defined peptidoglycan of bacterial cell wall, disaccharide tetrapeptide, was established from Lewis rats immunized with the antigen covalently linked to the autologous rat serum albumin. The antigen specificity was examined with various analogues or derivatives of the peptidoglycan. The cell line was reactive to analogues with the COOH-terminal D-amino acid, but least reactive to those with L-amino acid as COOH terminus. Transferring of the T cell line into X-irradiated normal Lewis rats induced delayed-type hypersensitivity in an antigen specific manner.     

Ultrastructure of a Hexagonal Array in Exosporium of a Highly Sporogenic Mutant of Clostridium botulinum Type A Revealed by Electron Microscopy Using Optical Diffraction and Filtration

The ultrastructure of a hexagonal array in the exosporium from spores of a highly sporogenic mutant of Clostridium botulinum type A strain 190L was studied by electron microscopy of negatively stained exosporium fragments using optical diffraction and filtration. The exosporium was composed of three or more lamellae showing an equilateral, hexagonal periodicity. Images of the single exosporium layer from which the noise had been filtered optically revealed that the hexagonally arranged, morphological unit of the exosporium was composed of three globular subunits about 2.1 nm in diameter which were arranged at the vertices of an equilateral triangle with sides of about 2.4 nm. The morphological units were arranged with a spacing of about 4.5 nm. The adjacent globular subunits appeared to be interconnected by delicate linkers.     

Isolation of Nontoxigenic Variants Associated with Enhanced Sporulation and Alteration in the Cell Wall from Clostridium botulinum Type A 190L by Treatment with Detergents

Nontoxigenic variants were isolated from Clostridium botulinum type A strain 190L after treatment with detergents such as deoxycholate, sodium dodecyl sulfate, Tween 80 and Brij-58. Deoxycholate was most effective for obtaining the variants. The variants exhibited a markedly increased frequency of sporulation compared with the oligosporogenic parent strain. The cell wall of the parent strain was composed of an outer layer and an inner layer, whereas that of the variants lost the outer layer. After treatment with mitomycin C the parent strain was subjected to lysis and produced bacteriophages with a hexagonal head and a contractible tail, while the nontoxigenic variants did not yield bacteriophages or phage-like structures. There appears to be a close relationship among the toxigenic and sporogenic properties, formation of the outer cell wall layer and lysogeny.     

Effect of Osmotic Stress on Turgor Pressure in Mung Bean Root Cells

Turgor pressure in cells of the elongating region of intactmung bean roots was directly measured by using the pressure-probetechnique. After the external osmotic pressure had been increasedfrom 0 MPa to 0.5 MPa, turgor pressure rapidly decreased byabout 0.5 MPa from 0.65 MPa to 0.14 MPa and root elongationstopped. Subsequent turgor regulation was clearly confirmed,which followed the osmotic adjustment to maintain a constantdifference in the osmotic pressure between root-cell sap andthe external medium ( II). It took at least 6 h for turgor pressureto recover to an adjusted constant level of about 0.5 MPa dueto turgor regulation, but rootelongation resumed within onlyan hour after the osmotic treatment. Therefore, the resumptionof root elongation under osmotic stress could not have beendirectly connected with turgor regulation. Furthermore, sincethe amounts of decrease in turgor pressure just after applicationsof various degrees of osmotic stress could be interpreted inrelation to those in II, hydraulic conductivity between theinside and the outside of root cells must be large enough toattain water potential equilibrium rapidly in response to osmoticstress. We conclude that turgor pressure in the cells of theelongating region of mung bean roots is determined mainly by II because of water potential equilibrium. (Received January 27, 1987; Accepted May 21, 1987)     

Membrane lipid changes in erythrocytes, liver and kidney in acute and chronic experimental liver disease in rats

Lipid molecules in lipoprotein surfaces exchange with their counterparts in cell plasma membranes. In human or experimental liver disease, plasma lipoprotein surfaces are enriched in cholesterol and deficient in arachidonate; corresponding alterations occur in membrane lipids of erythrocytes. To determine whether similar changes take place in membranes of nucleated cells, the lipid content of plasma and of erythrocyte, liver and kidney membranes was measured in rats with acute (3-day) galactosamine-induced hepatitis or chronic (3-week) biliary obstruction. In both models of liver injury the cholesterol:phospholipid ratio in plasma and in erythrocytes was significantly increased (P less than 0.001). Although this ratio was also elevated in liver and kidney microsomes, only in liver microsomes of obstructed rats was the increase significant (P less than 0.001). However, the cholesterol:phospholipid ratio of kidney brush-border membranes, was significantly higher in bile-duct-ligated rats; presumably, compensating mechanisms limit cholesterol accumulation in intracellular membranes. Kidney brush-border membranes from obstructed rats were deficient in arachidonate as were plasma and erythrocytes. However, arachidonate levels were unchanged in kidney microsomes; renal delta 6-desaturase, the rate-limiting enzyme in the conversion of linoleic acid to arachidonic acid, was increased by 50% (P less than 0.001) and may have counteracted a reduced supply of exogenous lipoprotein arachidonate. We conclude that in experimental liver disease lipoprotein-induced lipid abnormalities can occur in renal membranes, although compensatory mechanisms may operate; the alterations seen, cholesterol accumulation and arachidonate depletion, would be expected to interfere with sodium transport and prostaglandin production, respectively. Our findings support the hypothesis that lipid abnormalities in kidney membranes contribute to the renal dysfunction which is a frequent complication of human liver disease.