Search

Heparin precipitates of human and rat serum lipoproteins, dissolved, dialyzed, and analyzed by paper electrophoresis, were found to migrate as β-lipoproteins. The pre-β-lipoproteins disappeared. Using specific anti-human β- and α-lipoprotein sera it was shown that the heparin precipitate of human very low density lipoproteins (VLDL) contained β-lipoproteins, whereas the supernatant contained α-lipoproteins. This indicates that these components are dissociated by the heparin precipitation procedure. Following partial delipidation of the heparin precipitate, a procedure which exposes the antigenic site of the α-lipoprotein of the VLDL, it can be demonstrated that the α-lipoprotein component is completely removed by the heparin precipitation procedure. Partially delipidated rat VLDL showed four immuno-reactive components when reacted against rabbit anti-rat VLDL serum, but only one, corresponding to the β-lipoprotein, when reacted with rabbit antiserum to heparin precipitate.Chemical analysis of the lipid components of the heparin precipitate and supernatant of human and rat VLDL reveals that over 90% of the triglycerides are precipitated by the heparin and that the supernatant fraction contains lipoproteins having a phospholipid to protein ratio higher than any of the other lipoproteins.Upon reincubation of the dissolved and dialyzed human serum heparin precipitate and its supernatant a pre-β band reappeared on paper electrophoresis. The recombined pre-β-lipoprotein was isolated and found to react with anti-β-, but not with anti-α-lipoprotein serum. This is a characteristic of native pre-β-lipoproteins. Evidence has also been obtained that the high density lipoproteins combine only with the β-lipoproteins originally present in the VLDL.

Alternaria solani produced two homogeneous exocellular polysaccharide fractions when grown in shake culture with fructose as the carbon source and the NH4NO3 concentration of the medium 1.7 g/l. Chromatographic techniques indicated that fraction I contained glucose, galactose, and glucosamine in a 2.4:1:1 ratio whereas fraction II contained glucose, galactose, and mannose in a 6.4:1:1.2 ratio. Fraction I was found at levels seven times greater than II. Total polysaccharide produced was 1.8% of the dry weight of the mycelium and 1.2% of the available carbohydrate.Growth and polysaccharide production were greatest with fructose as the carbon source. Decreasing levels of growth occurred with mannitol, glucose, and sucrose, respectively. Exocellular polysaccharides were not detected with mannitol as carbon source. At 10 days, growth on fructose is maximum at NH4NO3 concentrations of 1.5 to 2.5 g/l, but exocellular polysaccharide production is maximum at 0.8 g/l. When produced on a medium of 2.0 g/l NH4NO3 the nitrogen content of I is double that when the medium is 0.8 g/l NH4NO3. In addition the ratio of I to II is about four times greater.

Two major improvements on a high voltage paper electrophoresis apparatus are described. Special tinned brass radiator plates have been very effective for cooling the system. Multichambered electrolyte vessels have facilitated the separation of various biological mixtures at several pH's in a single run at room temperature.

Glycerol kinase and glycerophosphate dehydrogenase activities have been demonstrated in the obligate halophile Halobacterium cutirubrum. Both enzymes are stereospecific for the formation of only the sn-3-glycerophosphate, and are associated with the cell envelope and cytoplasmic fractions. The stereospecificity of these enzymes in the obligate halophile is thus the same as in nonhalophiles and in higher organisms. The bearing of these findings on the biosynthetic pathway for the di-O-phytanyl glycerol ether phospholipids in H. cutirubrum is discussed.

Multiple electrophoretic species of arylsulfatase were demonstrated in sonicates of Proteus rettgeri by paper electrophoresis. Subsequent treatment of the sonicates with streptomycin sulfate and DEAE-cellulose chromatography resolved enzyme activity into four fractions. Electrophoretic examination of each chromatographic fraction revealed sulfatase heterogeneity comparable to that of the initial extract. These electrophoretic components differed in their general response to a number of arylsulfatase inhibitors. The results are discussed in relation to the finding of multiple species of arylsulfatase in other biological systems.

During a search for hemoglobin variants in Manitoba, two unrelated patients were found who appear to possess the trait for hemoglobin E Saskatoon (β22 Glu → Lys) on the basis of peptide map analyses of the variant fractions.