Rabbit autoantibodies to actin induced by immunization with modified homologous actins

Actin is a major antigen involved in the reaction of smooth muscle antibody positive sera from patients with chronic active hepatitis. In the present study, actin extracted from rabbit skeletal muscle was denatured by sodium dodecyl sulfate and was immunized into the rabbit, a homologous animal for actin. The rabbits, thus immunized, produced antibodies reactive with actins of homologous and heterologous animals. In addition, the antibodies showed reactivity with autologous actin. It indicates that the denatured homologous actin is capable of terminating immunological tolerance to actin and induces formation of autoantibody to rabbit actin. This phenomenon may be implicated in the occurrence of anti-actin antibody in sera from patients with chronic liver disease and several other diseases.     

Construction of protocellular structures under simulated primitive earth conditions

We have developed experimental approaches for the construction of protocellular structures under simulated primitive earth conditions and studied their formation and characteristics. Three types of envelopes; protein envelopes, lipid envelopes, and lipid-protein envelopes are considered as candidates for protocellular structures. Simple protein envelopes and lipid envelopes are presumed to have originated at an early stage of chemical evolution, interaction mutually and then evolved into more complex envelopes composed of both lipids and proteins.Three kinds of protein envelopes were constructedin situ from amino acids under simulated primitive earth conditions such as a fresh water tide pool, a warm sea, and a submarine hydrothermal vent. One protein envelope was formed from a mixture of amino acid amides at 80 °C using multiple hydration-dehydration cycles. Marigranules, protein envelope structures, were produced from mixtures of glycine and acidic, basic and aromatic amino acids at 105 °C in a modified sea medium enriched with essential transition elements. Thermostable microspheres were also formed from a mixture of glycine, alanine, valine, and aspartic acid at 250 °C and above. The microspheres did not form at lower temperatures and consist of silicates and peptide-like polymers containing imide bonds and amino acid residues enriched in valine. Amphiphilic proteins with molecular weights of 2000 were necessary for the formation of the protein envelopes.Stable lipid envelopes were formed from different dialkyl phospholipids and fatty acids.Large, stable, lipid-protein envelopes were formed from egg lecithin and the solubilized marigranules. Polycations such as polylysine and polyhistidine, or basic proteins such as lysozyme and cytochromec also stabilized lipid-protein envelopes.     

Effect of guanidinoethanesulfonic acid on brain monoamines in the mouse

Guanidinoethanesulfonic acid (GES) is known to induce convulsive seizures when administered intracisternally to rabbits and cats. The effects of GES on behavior, electroencephalographic recording and brain monoamine levels were examined in mice. When GES (900 nmol) was intraventricularly injected into mice, focal clonic movements of the face, vibrissae and ears together with twitching of the limbs were observed 0.5–1 min after the injection. Hypersensitivity was observed up to 7 min after the injection, after which the mice behaved normally. GES also induced sporadic spike discharges on electrocorticogram. The levels of 5-hydroxytryptamine (5-HT) of the GES-injected mice were lower than those of the saline-injected mice in the hippocampus, diencephalon, pons-medulla oblongata and cerebellum 5 min after the injection. No changes in the norepinephrine or dopamine levels were found after the GES injection. The level of 5-hydroxyindoleacetic acid increased in the striatum and cerebellum 5 min after the GES injection. These results suggest that GES-induced convulsive activities enhance the serotonergic neuroactivity in order to suppress the convulsions.     

Gene structure of human thrombomodulin, a cofactor for thrombin-catalyzed activation of protein C

The gene coding for human thrombomodulin, a thrombin receptor on endothelial cells and a cofactor for the activation of anticoagulant protein C zymogen, was isolated from a human genomic library by employing human thrombomodulin cDNA as a probe. The nucleotide sequences of the gene and the adjacent 5' and 3' flanking regions were then determined. The nucleotide sequence of this gene with approximately 3.7 kilobase pairs was identical to that of the cDNA, indicating that the gene for human thrombomodulin is free of introns. Hybridization data showed that there is only a single thrombomodulin gene in the human genome.     

Lysis of Phormidium luridum by Myxococcus fulvus in continuous flow cultures

D aft , M.J., B urnham , J.C. & Y amamoto , Y. 1985. Lysis of Phormidium luridum by Myxococcus fulvus in continuous flow cultures. Journal of Applied Bacteriology 59 , 73–80.
In two chemostat systems Myxococcus fulvus (strain BGO2) adhered to the glass walls of the growth vessel and on glass beads contained in a vertical glass column. The bacterium produced long colonial strands that extended towards the centre of the vessel. Both systems allowed measurement of lytic enzyme production and cyanobacterial predatory efficiency. Lysozyme activity produced by the myxococci was dependent on the concentration of the tryptone and the flow rate of the medium. Continuous lysis of Phormidium luridum occurred in both methods of culture in the presence of M. fulvus (strain BGO2). The results suggest that the adhesive characteristics of this bacterium prevent the achievement of steady state kinetics in either saprophytic or parasitic modes of growth. M. fulvus , with its various morphological growth forms and effectiveness in lysing cyanobacteria, is considered to be a potential control agent of cyanobacteria.     

Isolation and Characterization of an Escherichia coli ruv Mutant Which Forms Nonseptate Filaments After Low Doses of Ultraviolet Light Irradiation

Two ultraviolet light (UV)-sensitive mutants have been isolated from Escherichia coli K-12. These mutants, designated RuvA(-) and RuvB(-), were controlled by a gene located close to the his gene on the chromosome map. They were sensitive to UV (10- to 20-fold increase) and slightly sensitive to gamma rays (3-fold increase). Host cell reactivation, UV reactivation and genetic recombination were normal in these mutants. Irradiation of the mutants with UV resulted in the production of single-strand breaks in deoxyribonucleic acid, which was repaired upon incubation in a growth medium. After UV irradiation, these mutants resumed deoxyribonucleic acid synthesis at a normal rate, as did the parent wild-type bacteria, and formed nonseptate, multinucleate filaments. From these results we concluded that the mutants have some defect in cell division after low doses of UV irradiation, similar to the lon(-) or fil(+) mutant of E. coli. The ruv locus was divided further into ruvA and ruvB with respect to nalidixic acid sensitivity and the effect of minimal agar or pantoyl lactone on survival of the UV-irradiated cell. The ruvB(-)mutant was more sensitive to nalidixic acid than were ruvA(-) and the parent strain. There was a great increase in the surviving fraction of the UV-irradiated ruvB(-) mutant when it was plated on minimal agar or L agar containing pantoyl lactone. No such increase in survival was observed in the ruvA(-) mutant.     

Sensitivity of the fetal rat pituitary-adrenal system to corticotropin-releasing factor in organ culture.

Six groups of adrenal glands from 17-day fetal rats were explanted to organ culture for 2 days. In one group, adrenal gland was cultured alone, and in the remaining five groups adrenal gland was cultured with pituitaries from fetuses ranging in age from 14 to 18 days. In each of the groups, half of the cultures had corticotropin-releasing factor (CRF) added to the medium. A histometric parameter utilized the size of adrenocortical cells as an indicator of sensitivity of the pituitary-adrenal system. When 17-day adrenal gland was cultured alone, addition of CRF did not cause any enlargement of cortical cells. When the adrenal gland was cultured with two 14-day pituitaries, cortical cells were enlarged. Addition of CRF to this culture induced no further change. With two 15-day pituitaries in the presence of CRF, cortical cells were slightly larger than those in the absence of CRF. With 16- to 18-day pituitaries, a marked hypertrophy of cortical cells was induced, and the addition of CRF caused further acceleration in their enlargement. These results suggest that, in organ culture, 14-day pituitary can release some adrenocorticotropic hormone (ACTH) with or without additional CRF. Older pituitaries (16- to 18-day) can apparently release an amount of ACTH in the presence of CRF that is greater than their own spontaneous ACTH secretion.