Antioxidant Activities of Dihydrolipoic Acid and its Structural Homologues

The relationships between structure and antioxidant activity of dihydrolipoic acid (DHLA) were studied using homologues of DHLA: bisonor-DHLA (a derivative which lacks two carbons in the hydrophobic tail), tetranor-DHLA (which lacks four carbons) and a methyl ester derivative. It was observed that: i) DHLA homologues with shorter hydrocarbon tails (i.e., bisnor- and tetranor-DHLA) had greater ability to quench superoxide radicals (O^-₂); ii) no differences among homologues with different chain lengths were found for peroxyl radical (ROO) scavenging in aqueous solution, and iii) DHLA was the best membrane antioxidant in terms of ROO scavening and lipid peroxidation inhibition. Differences among the DHLA homologues in their antioxidant properties in polar and apolar environments generally agreed with differences in their partition coefficients. The methyl ester was the least effective antioxidant both in aqueous phase and in membranes. Tetranor-DHLA was found not only to be less effective in preventing ROO-induced lipid peroxidation, but also to induce lipid peroxidation in the presence of residual iron. Thus, the complexity of biological systems seems to complicate generalizations on the correlation of molecular structure with antioxidant activity of DHLA.     

Effect of a single administration of testosterone on the immune response and lymphoid tissues in mice.

Female mice were given a single intraperitoneal injection of testosterone immediately after irradiation and marrow reconstitution. Thirty days later testosterone had no suppressive effect on the recovery of thymus and spleen weights. Testosterone had no effect on the graft-versus-host reaction. Testosterone had no influence on the survival of the skin homografts. However, the plaque-forming cell response to sheep erythrocytes in the spleen was dramatically suppressed by testosterone. Histological observations revealed marked inhibition of lymphoid regeneration selectively in the thymus-independent areas of the peripheral lymphoid tissues. These results suggest that testosterone would act mainly on the differentiation of stem cells toward the population of bone marrow-derived B lymphocytes. The immune response to sheep erythrocytes was restored completely 90 days after testosterone administration. Testosterone given to normal adult mice can also have suppressive activity on the immune system 30 days after a single intraperitoneal injection.     

Inhibition of the Synthesis of Simian Virus 40 Antigens in Cells Preinfected with Yaba Tumor Virus

The synthesis of tumor and viral antigens after infection of an established line of cynomolgus monkey kidney cells with simian virus 40 (SV40) was compared in cells previously infected with Yaba virus and in cells not preinfected. SV40 failed to induce synthesis of tumor or viral antigens in cells preinfected with Yaba virus. The inhibitory state in preinfected cells was shown to develop sequentially. Increase in the rate of deoxyribonucleic acid synthesis in the nuclei of preinfected cells occurred after infection with SV40. This rate of increase was significantly lower than that which occurred in SV40-infected cells which had not been preinfected. Cytosine arabinoside did not exert significant effect on the development of the inhibitory effect against SV40 in Yaba virus-infected cells.     

Chromosome mapping in barley by means of telotrisomic analysis

Summary A total of 37 genetic markers located in chromosomes 2, 3, 4 and 5 were associated with specific arms by means of telotrisomic analysis in five telotrisomics (Triplo 2 L, 2 S, 3 S, 4 S, 5 L) of barley (Hordeum vulgare L.). The genes v, gp (= gp 2), li, gs 5, tr and msg2 showed a trisomic ratio with Triplo 2 L indicating that these genes were on the long arm of chromosome 2. A disomic ratio was obtained for genes wst 4, gs 5, and v with Triplo 2 S, confirming that these genes were on the long arm of chromosome 2(2 L). A disomic ratio was observed for genes e, f(= lg), sk, and gs6 with Triplo 2 L. Two genes, f(= lg) and gs6 showed a trisomic ratio with Triplo 2S. These results indicated that genes e, f(= lg), sk, and gs 6 are on the short arm of chromosome 2 (2S). Since only one telocentric chromosome was available for chromosome 3, 4 and 5, most of the well-mapped marker genes were tested with those telocentric chromosomes. The genes cu 2, uz, wst, als, gs 2, zb,f2, and cer-zn ³⁴⁸ showed trisomic ratio with the telocentric for chromosome 3. These genes were located on the short arm of chromosome 3 (Robertson 1971). This indicated that the telocentric chromosome is for the short arm of chromosome 3(3 S). A disomic ratio was obtained for genes yst, x _c, al, yst2, a _n, ari-a ⁶ and x _s, indicating that these genes are on the long arm of chromosome 3. Two genes, f9 and K, showed trisomic ratio with the telocentric chromosome for 4, while genes gl(= gl2), br2, yh, lg 3, lg 4 and lk 5 showed disomic ratios. This indicated that the telocentric chromosome is for the short arm of chromosome 4. Two genes, fs 2 and g, were studied with Triplo 5 L. Both showed trisomic ratio, indicating that fs 2 and g are located on Triplo 5 L. The centromere position (C) on chromosome 2, 3 and 4 was thus located as (the left side of C is the short arm and the right is the long arm): chromosome 2: f — sk — gs6 — e — C — gs5 — msg2 — wst4 — v — gp — li — tr; chromosome 3: f2 — cer-zn ³⁴⁸ — uz — gs2 — als — cu2 — wst — zb — C — yst — x _c — al — yst2 — a _n — ari-a ⁶ — x _s; chromosome 4: f9 — K — C — lg4 — lg ³ — gl2 — br2 — lk5 — yh. The centromere position on chromosome 5 was not precisely located.Contribution from the Department of Agronomy, Published with the approval of the director of the Colorado State University Experiment Station as Scientific Series Paper No. 2606. This research was supported in part by by NSF Grant GB 4482X and GB 30 493 to T. Tsuchiya and Colorado State University Experiment Station Hatch Project     

Isolation and characterization of the nuclei fromSaccharomyces cerevisiae

We isolated highly intact nuclei from cells of a haploid strain ofSaccharomyces cerevisiae. The isolated nuclei were spherical, maintained a double membrane with typical nuclear pores, and were free from mitochondrial-, vacuolar-, and cytoplasmic-marker enzymes. The nuclei could synthesize both DNA and RNA and could phosphorylate nuclear proteins in vitro. These biochemical activities were greatly affected by the osmotic treatment of the nuclei.     

Rapid determination of glycine- and taurine-conjugated bile acids in human bile by high-performance liquid chromatography

With use of an anion-exchange packing, TSK Gel IEX 540 DEAE, for high-performance liquid column chromatography, glycine- and taurine-conjugated bile acids were separated in 10 min and detected with a differential refractometer. Human bile could be analyzed after a simple pretreatment. The purity of the peaks of glycine- and taurine-conjugated bile acids in human bile was confirmed by enzymatic determination using 3α-hydroxysteroid:NAD oxidoreductase. The molar ratios of the two forms of the conjugates (glycine/taurine ratios) in bile from normal subjects and from patients suffering from various hepatobiliary diseases were measured.     

A short period oscillation in a water/oil/water system

A new kind of potential oscillation with a short period of 7.5 s was found to occur in a water/oil/water system which consisted of an aqueous solution of surfactant, nitrobenzene and an aqueous solution of NaCI. A long period (approximately 10 min) oscillation previously reported was also found to be superposed on the new oscillation. The power spectrum of the short period oscillation has been measured.     

Theoretical description of release, uptake, and pulse chase of labeled subunits of actin or a microtubule that undergoes head-to-tail polymerization

The notion of the number of once-visited sites by a one-dimensional random walker is used to describe the amount of release, uptake, and pulse chase of labeled subunits of actin, or a microtubule that undergoes head-to-tail polymerization or treadmilling. Exact formulae for any number of steps are given as well as all the possible asymptotic forms of these quantities. Numerical calculations are carried out using hypothetical and experimentally measured values of rate constants.