28,000-dalton polypeptide (p28) of adult T-cell leukemia-associated antigen encoded by 24 S mRNA of human T-cell leukemia virus has an associated protein kinase activity

Human T-cell leukemia virus producer cell line MT-2 was labeled with [32P]phosphoric acid, and its cell extracts were immunoprecipitated with mouse monoclonal antibodies (GIN-7, and KK-1) and rabbit sera (anti-p24, and anti-gp68). Analysis of the immunocomplexes on sodium dodecyl sulfate-polyacrylamide gell electrophoresis revealed that p53, p28, and p19 of adult T-cell leukemia-associated antigens were phosphorylated in vivo. Immunocomplexes of MT-2 cell extract with monoclonal antibody KK-1 were incubated with [gamma-32P]ATP in vitro and it was revealed that the phosphokinase activity was associated with p28. The phosphokinase activity of p28 was specific to the serine residue but was not to the tyrosine residue.     

The reaction of superoxide radical with catalase. Mechanism of the inhibition of catalase by superoxide radical

We have studied the time course of the absorption of bovine liver catalase after pulse radiolysis with oxygen saturation in the presence and absence of superoxide dismutase. In the absence of superoxide dismutase, catalase produced Compound I and another species. The formation of Compound I is due to the reaction of ferric catalase with hydrogen peroxide, which is generated by the disproportionation of the superoxide anion (O-2). The kinetic difference spectrum showed that the other species was neither Compound I nor II. In the presence of superoxide dismutase, the formation of this species was found to be inhibited, whereas that of Compound I was little affected. This suggests that this species is formed by the reaction of ferric catalase with O-2 and is probably the oxy form of this enzyme (Compound III). The rate constant for the reaction of O-2 and ferric catalase increased with a decrease in pH (cf. 4.5 X 10(4) M-1 s-1 at pH 9 and 4.6 X 10(6) M-1 s-1 at pH 5.). The pH dependence of the rate constant can be explained by assuming that HO2 reacts with this enzyme more rapidly than O-2.     

Visible fibrinolysis by endothelial cells: Effect of vitamins and sterols

We have succeeded in corroborating the enhancing effect of vitamin A, vitamin C, sitosterol and fucosterol on the fibrinolytic activity of endothelial cells. The assay system consisted of anin situ dissolution of a fibrin layer coated onto a culture dish, over which endothelial cells were grown in a culture medium containing 10 % serum. The dissolution was enhanced by the addition of these vitamins and phytosterols to the culture medium.To whom correspondence should be addressed.     

Chemical modification of lipase with ferromagnetic modifier — A ferromagnetic-modified lipase

Summary A ferromagnetic modifier was prepared by reacting ferrous(Fe²⁺)- and ferric(Fe³⁺)-ions with polyethylene glycol having two carboxyl groups (MW:2000) at pH 8.0–8.5. Lipase fromPseudomonas fragi 22–39B was coupled with the modifier using water-soluble carbodiimide. The modified lipase, which was dispersed into buffered solutions in the size range of 30–70 nm, exerted the hydrolytic activity of 8.0 U/mg. In a magnetic field of 250 Oe, the ferromagnetic-modified lipase was readily recovered from the colloidal solution.     

Characterization of a chloroplast DNA sequence from Chlorella ellipsoidea that promotes autonomous replication in yeast

Summary An EcoRI 2.7 kbp fragment from Chlorella ellipsoidea chloroplast DNA (cpDNA) cloned in YIp5 was shown to promote autonomous replication in Saccharomyces cerevisiae. The fragment was localized in the small single copy region close to the inverted repeat. The ARS activity (autonomously replicating sequences in yeast) was found to be confined within a subclone of a ca. 300 bp HindIII fragment. Sequence analysis of this fragment revealed its high AT content and the presence of several direct and inverted repeats and a few elements that were related to the yeast ARS consensus sequence. Electron microscopic studies revealed that this sequence did not coincide with the primary replication origin of chloroplast DNA. The functioning of this sequence as a possible origin of plasmid replication in vivo is discussed. This is the first report on Chlorella cpDNA sequence. re]19850821 rv]19851211 ac]19851216     

Comparison of promoter activities of heterologous and homologous promoters in Bacillus subtilis

Summary We have constructed promoter probe vectors with the Escherichia coli galactokinase monitoring system that can be used in Bacillus subtilis. In vivo studies with these vectors demonstrated that the E. coli trp and tac(trp::lac) promoter regions could be utilized in B. subtilis. These promoter regions and the promoter region for the erythromycin resistance gene originating from Staphylococcus aureus were preferentially utilized during the stationary growth phase of B. subtilis, whereas the B. subtilis P21K and P29K promoters were utilized during the exponential growth phase and decreased rapidly during the stationary phase. The apparent strength of these promoters of E. coli in B. subtilis, in terms of galactokinase units, was comparable with those of the B. subtilis promoters.     

Culture of intramural cardiac ganglia of the newborn guinea-pig

Summary The present study describes the ultrastructure of non-neuronal cells and their interrelationships with intracardiac neurones present in cultures dissociated atria and interatrial septum from newborn guinea-pig. When compared with the in situ preparation, most of these features in culture were similar to those observed in situ, but some differences were also apparent. Both mature and immature Schwann cells were observed in culture, and as in situ, the latter were closely associated with intracardiac neurones, whilst the former were more widely separated. The ultrastructure of satellite cells was more variable in culture than in situ: three general types were distinguished on the basis of their 10-nm filament content. This variation could be due to conditions of culture. Interstitial cells were present in culture and closely resembled those described in situ, although there was less space between cultured interstitial cells and their associated cells. Many fibroblasts, some myoblasts and a few mast cells were also found in the culture preparations.     

Do protozoa conceal a high potency of nucleoside triphosphate hydrolysis present in Toxoplasma gondii?

ATP hydrolytic activity in whole cell homogenates of some protozoa was assayed in the presence or absence of dithiothreitol. The activities in all protozoan cell homogenates, except Toxoplasma gondii, ranged from 0.6 to 32 mumol/mg protein/hr, irrespective of the presence or absence of dithiothreitol. A remarkably higher activity, 11,690 mumol/mg protein/hr, was observed for T. gondii in the presence of dithiothreitol. These results indicate that the higher ATP hydrolytic potency observed for T. gondii is not universal to protozoa, rather it is unique to T. gondii.