Metabolism of 9-(1,3-dihydroxy-2-propoxymethyl)guanine, a new anti-herpes virus compound, in herpes simplex virus-infected cells

The metabolism of 9-(1,3-dihydroxy-2-propoxymethyl)guanine (DHPG), one of the most promising new anti-herpes virus compounds, in HeLa cells infected with herpes simplex virus type 1 was compared with that in the uninfected HeLa cells. In the virus-infected cells, the uptake of DHPG was enhanced and the major metabolites were found to be the mono-, di-, and triphosphate derivatives. The formation of these metabolites was dependent on the extracellular concentration of DHPG (0.5 to 5.0 microM). Virus-induced thymidine kinase was capable of phosphorylating DHPG to its monophosphate which could be further phosphorylated to the di- and triphosphate derivatives by the host cellular enzymes. Incorporation of the DHPG into DNA was observed in virus-infected cells. In contrast with 9-(2-hydroxyethoxymethyl)guanine, DHPG seemed not to serve as a chain terminator, but to be incorporated internally into DNA strands.     

Preparation and antigenic property of methyl 3 beta-hydroxy-19-oxo-5-cholen-24-oate 19-(O-carboxymethyl) oxime-bovine serum albumin conjugate

The preparation and antigenic property of 3 beta-hydroxy-5-cholen-24-oic acid-bovine serum albumin (BSA) conjugate in which the hapten is linked to the carrier protein through an (O-carboxymethyl) oxime bridge at the C-19 position on the steroid nucleus is described. Antibody raised against antigen in the rabbit possessed high titer and specificity to 3 beta-hydroxy-5-cholen-24-oic acid, exhibiting no significant cross-reactions with various bile acids.     

Superinfection with R Factors by Transduction in Escherichia coli and Salmonella typhimurium

Superinfection immunity is found in the conjugal transfer of R factors between two fi(+) R factors and between two fi(-) R factors (fi = fertility inhibition), as we reported previously. In contrast, no reduction in the frequencies of transduction of an fi(+) R factor 222 was caused by the presence of fi(+) R factors in the recipients in transduction systems with phage P1kc in Escherichia coli K-12 and with phage P22 in Salmonella typhimurium LT-2. The absence of superinfection immunity in transduction may be due to the difference in the route of entry of the R factor. The frequencies of transduction of an fi(+) R factor were reduced, although slightly, by the presence of fi(-) R factors in the recipients. This reduction is probably due to host-controlled restriction of the entering fi(+) R factor by the fi(-) R factors in the recipients, since transduction of an fi(+) R factor by the transducing phage propagated on the strain carrying both fi(+) and fi(-) R factors was not reduced by the presence of homologous fi(-) R factors in the recipients. The fi(+) R factor 222, when transduced to the recipient strains carrying other R factors, recombined genetically at high frequencies with these resident R factors, regardless of their fi type.     

Esterified and total 7 alpha-hydroxycholesterol in human serum as an indicator for hepatic bile acid synthesis

Serum levels of 7 alpha-hydroxycholesterol and activities of hepatic microsomal cholesterol 7 alpha-hydroxylase in surgical patients were analyzed by capillary gas-liquid chromatography-selected ion monitoring technique using a new internal standard, 5 alpha-cholestane-3 beta, 7 beta-diol. We found that concentrations of 7 alpha-hydroxycholesterol obtained after alkaline hydrolysis were higher than those without alkaline hydrolysis, indicating that a considerable amount of 7 alpha-hydroxycholesterol in human serum is present in esterified form. Esterified 7 alpha-hydroxycholesterol could also be quantitatively hydrolyzed with cholesterol esterase, suggesting that fatty acid is bound at the 3 beta-position of the cholestenediol. The serum levels of esterified and free 7 alpha-hydroxycholesterol in patients with cholelithiasis were 198.0 +/- 90.3 and 48.3 +/- 19.8 pmol/ml (mean +/- SD), respectively, and were similar to those in patients without hepatobiliary diseases. After treatment with chenodeoxycholic acid (300 mg per day) for 7 to 10 days, esterified and free 7 alpha-hydroxycholesterol levels decreased to 64.9 +/- 33.6 and 20.5 +/- 11.1 pmol/ml, respectively. Activity of cholesterol 7 alpha-hydroxylase was also inhibited. Treatment with ursodeoxycholic acid (600 mg per day) for 7 to 10 days had no inhibitory effect on serum 7 alpha-hydroxycholesterol levels and the enzyme activity. In all groups, high correlations were found between the activity of cholesterol 7 alpha-hydroxylase and serum levels of 7 alpha-hydroxycholesterol: free (r = 0.71, n = 38, P less than 0.001); esterified (r = 0.87, n = 38, P less than 0.001); total (r = 0.87, n = 38, P less than 0.001). Esterified and total 7 alpha-hydroxycholesterol was more highly correlated with the enzyme activity than the free form. We conclude that a significant amount of 3 beta-acyl esters of 7 alpha-hydroxycholesterol is present in human serum and that serum levels of esterified and/or total 7 alpha-hydroxycholesterol are likely to reflect the activity of hepatic cholesterol 7 alpha-hydroxylase and thus the amount of primary bile acids synthesized in the liver.     

Differentiation of germ cells in seminiferous tubules transplanted to testes of germ cell-deficient mice of W/Wv and Sl/Sld genotypes

(WB X C57BL/6)F1-W/Wv (hereafter, WBB6F1-W/Wv) mice and (WC X C57BL/6)F1-Sl/Sld (hereafter, WCB6F1-Sl/Sld) mice are sterile due to the deficient spermatogenesis in the testes. The cause of deficient spermatogenesis in WBB6F1-W/Wv mice is considered to be a defect in germ cells themselves, whereas that in WCB6F1-Sl/Sld mice is considered to be a defect in tissue environment necessary for differentiation of germ cells. Seminiferous tubules isolated from cryptorchid testes of C57BL/6- +/+ mice were transplanted into the testes of WBB6F1-W/Wv and WCB6F1-Sl/Sld mice to clarify that the extratubular environment of these mice was intact or not. Type A spermatogonia in the transplanted tubules normally differentiated into spermatids, suggesting that the extratubular environment is intact in both WBB6F1-W/Wv and WCB6F1-Sl/Sld mice.