Isolation and characterization of four plasmids from Bacillus subtilis

Nineteen Bacillus subtilis isolates obtained from type culture collections were examined for the presence of covalently closed circular duplex deoxyribonucleic acid molecules by the technique of cesium chloride-ethidium bromide density gradient centrifugation. Four of the 19 strains tested carried covalently closed circular molecules. Two of these strains (IFO3022, IFO3215) harbored a similar plasmid with a molecular weight of 5.4 X 10(6). The other two strains (IAM1232, IAM1261) carried 4.9 C 10(6)-and 5.3 X 10(6)-dalton plasmids, respectively. These plasmid-harboring strains did not show phenotypic traits such as antibiotic resistance orbacteriocin production. The plasmid deoxyribonucleic acids were digested by three restriction endonucleases, EcoRI, HindIII, and BamNI, and were classified into three different types from their electrophoretic patterns in agarose gels.

Control of tryptophan synthetase amplified by varying the numbers of composite plasmids in Escherichia coli cells

Using pSC101, RSF1010, RSF2124 and RP4 plasmids as vectors and bacteriophage lambdatrpD-A60-3 DNA as a source of the Escherichia coli whole tryptophan operon, composite plasmids of pSC101-trp, RSF1010-trp, RSF2124-trp and RP4-trp were constructed in vitro with EcoRI restriction endonuclease and DNA ligase. Each composite plasmid could be maintained stably in E. coli cells. The copy number of pSC101-trp, RSF1010-trp, RSF2124-trp and RP4-trp were 4.2, 11.2, 11.9 and 1.6 per chromosome respectively. The tryptophan synthetase activities in cells containing pSC101-trp, RSF1010-trp, RSF2124-trp aand RP4-trp plasmid were found to be 2.1, 6.0, 5.0 and 2.5 times compared with the level in chromosomal trp+ cells when they were grown in a minimal medium. By partial derepression with indolylacrylic acid, the enzyme levels were elevated to 10.1, 16.3, 15.3, 12.3 times, respectively, that of the control cells. The tryptophan synthetase activities did not increase in proportion to the copy number of the plasmids, but were strongly affected by the repression system of host cells.

Inhibition of sterol synthesis by citrinin in a cell-free system from rat liver and yeast

Citrinin, a fungal metabolite known as an antibiotic, strongly inhibited the labeled acetate incorporation into nonsaponifiable lipids by a cell-free system from rat liver but not the labeled mevalonate incorporation. Of the enzymes involved in cholesterol synthesis, two enzymes, acetoacetyl-CoA thiolase (EC 2.3.1.9) and 3-hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.34), were specifically inhibited by the antibiotic. The concentration required for 50% inhibition was 0.2 mM for the former enzyme and 0.5 mM for the latter. Essentially the same results were obtained with a cell-free system from yeast although higher concentrations of the antibiotic were required for inhibition.

beta-actinin, a regulatory protein of muscle. Purification, characterization and function

beta-Actinin, a minor regulatory protein of muscle, was purified from skeletal muscles of rabbit and chicken by DEAE-Sephadex chromatography. beta-Actinin consisted of two subunits, beta I and betaII, with chain weights of 37,000 and 34,000 daltons, respectively. The amino acid compositions were similar, though not identical. It appears that each of the two subunits is associated in solution. beta-Actinin had the following effects on actin: (1) inhibition of reassociation of F-actin fragments; (2) inhibition of network formation of F-actin; (3) inhibition of growth of F-actin fragments; (4) retardation of depolymerization of F-actin and (5) acceleration of polymerization of G-actin. All these actions of beta-actinin can be explained in terms of action as an "ending factor". Experimental evidence favored the view that beta-actinin is bound to one end of the F-actin filament, namely to the end opposite to the direction of polymerization. Fluorescence-labeled anti-beta-actinin stained the middle portion of the A band of myofibrils. Based on the finding that the stain was unchanged on removal of myosin, it is suggested that beta-actinin is located at the free ends of the I filaments of myofibrils. Thus is seems likely that beta-actinin functions as an ending factor for actin filaments.

[Comparative results of cephacetrile with cefazolin in complicated urinary tract infections by means of double-blind trials (author's transl)]

In order to elucidate the usefulness of cephacetrile (CEC), comparative trials with cefazolin (CEZ) were carried out in the patients with complicated infections of the urinary tract, and the following results were obtained: 1. There were no statistically significant differences or tendencies observed between the groups given CEC and CEZ in either of the global effects, bacteriological effects, rate of superinfection, relapse, relapse with bacterial alternation, drug usefulness, rate of improvements in symptoms and findings in all the cases. 2. According to a result of stratified analyses, there were statistically significant differences observed, showing more inferior results of CEC than CEZ in either stratum of "below 50" in the age, "acute" in the disease phase, "infections of the upper urinary tract" in the disease pattern, and "E. coli including mixed infections with gram-positive organisms" in the pathogenic strains. However, it should be taken into consideration that certain background factors influence greatly in the effects and there were some problems on deviated backgrounds in these strata. On the other hand, CEC displayed better bacteriological effects than those of CEZ in higher stratum of "chronic" in the disease phase and "Klebsiella, Proteus, Citrobacter, Enterobacter including mixed infections" in the pathogenic strains, and statistically significant differences were not observed. 3. In consequence of bacteriological studies, CEC showed stronger resistance than CEZ against beta-lactamase produced in all the strains of gram-negative bacilli. Particularly there were significant differences or tendencies observed in those of Proteus, Cirtobacter, and Enterobacter, and at the same time there were great differences in the activity of beta-lactamase between CEC and CEZ as the substrate. 4. In correlation of the MIC and effects, CEC showed weaker actions than CEZ against susceptible organisms, but slightly stronger actions against moderately or highly resistant strains. A study of the relationship between the MIC of pathogenic strains, beta-lactamase, and bacteriological effects, showed possibilities that even the high activity of beta-lactamase results in remarkable effects in susceptible strains and the drugs with stronger resistance against beta-lactamase given better results in moderately or highly resistant organisms. 5. The incidence rate of adverse reactions was 2 out of 51 cases in the CEC group (3.9%) and 3 out of 50 cases in the CEZ group (6.0%), showing no significant difference, and those symptoms were similar. In conclusion, when the usefulness of CEC in complicated infections of the urinary tract is compared with that of CEZ, the former is said to be equal to the latter without significant difference as a whole...

Gamma-Actinin, a new regulatory protein from rabbit skeletal muscle. I. Purification and characterization

A new regulatory protein which we have designated as gamma-actinin has been isolated from native thin filaments of rabbit skeletal muscle. Depolymerized native thin filaments were fractionated by salting out with ammonium sulfate, and the precipitates obtained at 40--60% ammonium sulfate saturation were further subjected to DEAE-Sephadex and Sephadex G-200 column chromatography. The purified gamma-actinin was shown to have a chain weight of 35,000 daltons and had a strong inhibitory action on the polymerization of G-actin. The results of amino acid analysis indicated a unique amino acid composition of gamma-actinin as compared with other structural proteins of muscle. Non-polar and neutral amino acid residues were abundant. One cysteine residue was contained per one molecule of gamma-actinin and played a critical role in the maintenance of the inhibitory activity. Pelleting of gamma-actinin with F-actin showed that gamma-actinin binds to F-action.

Gamma-Actinin, a new regulatory protein from rabbit skeletal muscle. II. Action on actin

The interaction of gamma-actinin and actin was investigated under various conditions. It has been shown that gamma-actinin affects the G-F transformation of actin, causing an increase in the number of actin monomers required to form a nucleus in the initial step of polymerization. Sonicated fragments of F-actin and heavy meromyosin caused the immediate polymerization of actin under the influence of gamma-actinin. Therefore, it can be concluded that gamma-actinin inhibits the nucleation step of G-F transformation. Actin filaments which were formed in the presence of gamma-actinin (F-actin) were shown to possess certain characteristic properties when compared with control F-actin. These were as follows: F-actin solution had a high critical concentration; F-actin showed a high rate of depolymerization; the flow birefringence of F-actin decreased with time upon incubation in the absence of free ATP; finally, F-actin was demonstrated to have ATP-splitting activity. These dynamic features of F-actin were accounted for in terms of an increase in the rate constant of depolymerization in F-actin under the influence of gamma-actinin.

Repolymerizability of native thin filaments of rabbit skeletal muscle

The repolymerizability of native thin filaments of rabbit skeletal muscle was examined under various conditions. The native thin filaments usually did not repolymerize after depolymerization, but it was found that the process was only inhibited at the nucleation step of the G-F transformation of actin. The inhibited state was released by the addition of sonicated F-actin fragments as seeds or by direct sonication. An attempt to isolate the actin moiety from native thin filaments showed that the isolated actin was very similar to Straub-type G-actin2 in its polymerizability. However, a protein factor which inhibits the polymerization of G-actin was obtained by ammonium sulfate fractionation of the depolymerized native thin filaments. Thus, the apparent lack of repolymerizability of native thin filaments was found to be due to the action of this factor on the polymerization of G-actin.

Inhibition of in vitro cholesterol synthesis by fatty acids

Inhibitory effect of 44 species of fatty acids on cholesterol synthesis has been examined with a rat liver enzyme system. In the case of saturated fatty acids, the inhibitory activity increased with chain length to a maximum at 11 to 14 carbons, after which activity decreased rapidly. The inhibition increased with the degree of unsaturation of fatty acids. Introduction of a hydroxy group at the alpha-position of fatty acids abolished the inhibition, while the inhibition was enhanced by the presence of a hydroxy group located in an intermediate position of the chain. Branched chain fatty acids having a methyl group at the terminal showed much higher activity than the corresponding saturated straight chain fatty acids with the same number of carbons. With respect to the mechanism for inhibition, tridecanoate was found to inhibit acetoacetyl-CoA thiolase specifically without affecting the other reaction steps in the cholesterol synthetic pathway. The highly unsaturated fatty acids, arachidonate and linoleate, were specific inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA synthase. On the other hand, ricinoleate (hydroxy acid) and phytanate (branched-chain acid) diminished the conversion of mevalonate to sterols by inhibiting a step or steps between squalene and lanosterol.

Occurrence of renovascular hypertension in two sisters

Renovascular hypertension in two sisters, aged 22 and 20, respectively, has been described. Renal artery stenoses were observed unilaterally in the elder patient and bilaterally in the younger one. In both patients, the functional significance of unilateral stenosis of the renal artery was documented by the renal vein renin ratio between the affected side and the contralateral or less affected side. High blood pressure and elevated plasma renin activity have been normalized with a unilateral revascularization in the elder patient, and with the treatment of propranolol in the younger one. The histological examination of the stenotic renal artery in the elder patient showed a finding comparable to the perimedial fibroplasia in Harrison and McCormack's classification of idiopathic fibromuscular stenosis.

Oxidation of tryptophan in lysozyme by ozone in aqueous solution

A tryptophan residue in hen's egg-white lysozyme [EC 3.2.1.17] was modified by ozone in an aqueous solution. One of the six tryptophan residues in the enzyme was oxidized to N'-formylkynurenine with concomitant loss of the enzymatic activity. Physicochemical studies of this modified enzyme (OL-I) revealed that the ozonization of lysozyme in aqueous media resulted in little change of the gross molecular conformation. It was deduced that the modified tryptophan residue in OL-I was possibly located in position 62 (or 63) of the protein.