Characterization of a mutation that causes overproduction of inositol in Neurospora crassa.

Slow-growing (inl+/-) spontaneous mutants have been isolated from an inositol requiring (inl) strain of Neurospora crassa that produces defective myo-inositol-1-phosphate synthase (MIPS), the enzyme responsible for the production of inositol-1-phosphate from glucose-6-phosphate. The defective enzyme has some residual activity. In the inl+/- strain the synthesis of the defective enzyme is enhanced, which enables the strain to grow slowly on minimal medium.

Inefficient binding of IgM immune complexes to erythrocyte C3b-C4b receptors (CR1) and weak incorporation of C3b-iC3b into the complexes.

The binding of soluble complement-reacted IgM immune complexes (IC) to erythrocyte (E) C3b-C4b receptors (CR1) and the incorporation of C3b-iC3b into solid phase IgM-IC was investigated. The optimal binding of liquid phase IgM-IC to E-CR1 was obtained with IC formed at moderate antibody excess, but the binding was low (2-3%) when compared to the binding of the corresponding IgG-IC (50-60%). Solid phase IC were prepared by coating microwells with heat-aggregated bovine serum albumin (BSA) followed by incubation with rabbit IgM anti-BSA antibody.

Defective myo-inositol-1-phosphate synthase production in an inositolless double mutant Neurospora crassa strain.

A slow growing inl+/- mutant was isolated from an inositol dependent (inl) Neurospora crassa strain. The latter strain produces defective myo-inositol-1-phosphate synthase which has residual activity. Inositol, similarly to that found in wild and inl mutant strains, represses the enzyme production in the inl+/- strain as well.

Acid phosphatase activity in monocytes and sera of patients with Hodgkin's disease.

Acid phosphatase (AP) levels have been found to be decreased in monocytes of 38 patients with Hodgkin's disease as compared to 16 healthy subjects. Low cellular AP activity was associated with the presence of active disease, stage IV and lymphocyte depletion type. Lactate dehydrogenase (LDH) was decreased in monocytes of patients but the difference did not reach statistical significance.

Characterization of inl+ transformants of Neurospora crassa obtained with a recombinant cosmid-pool.

We constructed a Neurospora crassa gene library in a cosmid vector and used the cosmid-pool DNA to transform an inl, rg Neurospora crassa strain to inositol prototrophy. The inl+ colonies obtained in this experiment proved to be integrative type transformants. Genetic analysis revealed that the integration event occurred at or near the inl locus.

Monocyte activation in patients with Hodgkin's disease.

Transglutaminase activity in monocytes and serum lysozyme level were tested in 40 patients with Hodgkin's disease and were found to be significantly increased. Transglutaminase activity in monocytes from patients in a clinically active stage of the disease was higher than in clinically inactive cases of HD, and varied along with the histological subtypes. Serum lysozyme varied with the stage of the disease and with the symptomatology as well as with the histological subtype.

Possible role of a regulatory gene product upon the myo-inositol-1-phosphate synthase production in Neurospora crassa.

The regulatory effect of inositol on inositol-1-phosphate synthase in Neurospora crassa strains was studied. Inositol represses enzyme production in the cultures of the wild type and that of the thermosensitive inositol-requiring mutant grown at 22 degrees C. Enzyme activity as well as the quantity of enzyme protein decreased sharply in both strains by increasing concentrations of inositol in the medium.

Signals of monocyte activation in patients with SLE.

The Fc receptor mediated reaction, the beta-glucuronidase and the lactic dehydrogenase activities of monocytes and the serum lysozyme level were tested together with the circulating immune complex content of patients with systemic lupus erythematosus. Simultaneously with the increasing FC receptor-mediated reaction and the elevated enzyme activities of patient monocytes, the secretion of lysozyme and the immune complex content of the sera were higher than those of the controls. A positive correlation was demonstrated between the Fc receptor-mediated reaction, the beta-glucuronidase activity, the lysozyme secretion and the immune complex content of the sera.

Monocyte activation by immune complexes of patients with SLE.

1. IC precipitated by PEG from patients with SLE inhibit in vitro the FcR dependent reaction of normal monocytes with sSRBC, while the C3bR dependent reaction of the cells with sensitized yeast is reduced only by some of them. The monocytes were preincubated with the IC for 30 min at room temperature.

Enzyme-linked immunosorbent assay for antibodies to native DNA in sera of patients with SLE.

A micro-ELISA technique has been developed to measure antibodies to native DNA and used in SLE patients. The distribution of antibody to native DNA in the main immunoglobulin classes was studied, using anti-human globulin conjugates labelled with peroxidase. the antigen (double-stranded DNA from calf thymus) used in the assay was adsorbed to the surface of polystyrene plates treated with methylated bovine serum albumin.

Separation of Neurospora crassa myo-inositol-1-phosphate synthase from glucose-6-phosphate dehydrogenase by affinity chromatography.

The purification of Neurospora crassa myo-inositol-1-phosphate synthase (EC 5.5.1.

Demonstration of myo-inositol-1-phosphate synthase and its assumed defective variant in various Neurospora crassa strains by immunological methods.

Immunological experiments were performed to demonstrate myo-inositol-1-phosphate synthase (EC 5.5.1.

A comparative study of DNA-induced transformants and spontaneous revertants of inositolless Neurospora crassa.

Inositolless (inl-) Neurospora crassa strains were treated with DNA (allo-DNA) of wild type N. Crassa. Hyphal fragments of a mycelial suspension of the N.

Factors influencing the uptake of DNA by Neurospora crassa.

Under optimal conditions intact Neurospora crassa cells incorporated nearly the same amount of 3H-labelled DNA as that of the endogenous DNA content of cells. After 18 h of incorporation more than 80 per cent of the radioactivity was retained in the cells. A maximum uptake of exogenous DNA occurred at 28 degrees C, pH 6.

Investigations on myo-inositol-1-phosphate synthase from the wild type and the inositol-dependent mutant of Neurospora crassa.

The inositol-dependent mutant of Neurospora crassa lacks inositol-1-phosphate synthetase activity. This defect can be revorted by the addition of high-molecular DNA isolated from the wild type. To elucidate the biochemical background of inositol dependence, inositol-1-phosphate synthetase was studied.

Conditions of transformation by DNA of Neurospora crassa.

The DNA uptake and transformation of inositol-requiring recipient Neurospora strains were investigated. Exponentially growing cultures can accumulate 5-10 fold quantities of donor DNA than older ones. The rate of DNA uptake depends on the physiological state of the recipient cell, and on the molecular weight of donor DNA.

Polynucleotides containing 5-mercapto-substituted pyrimidines: inhibition of viral DNA polymerases and the biological implication.

Partially thiolated polycytidylic acids MPC I-III, containing 1.7%, 3.5% and 8.