Showing papers by "Public Health Research Institute published in 1978"
TL;DR: Evidence is given that pSA2100, an in vivo recombinant of pSA0501 and pCM194 (S. aureus), arose by a fusion of the latter plasmids, possibly by insertion of one element into another as a translocatable element.
Abstract: Covalently closed circular DNA from five Staphylococcus aureus plasmids has been introduced into Bacillus subtilis. Four of these plasmids (pUB110, pCM194, pSA2100, and pSA0501) have been selected for further study. These plasmids replicate as multicopy autonomous replicons in both Rec+ and Rec- B. subtilis strains. They may be transduced between B. subtilis strains or transformed at a frequency of 10(4) to 10(5) transformants per microgram of DNA. The molecular weights of these plasmids were estimated, and restriction endonuclease cleavage site maps are presented. Evidence is given that pSA2100, an in vivo recombinant of pSA0501 and pCM194 (S. Iordanescu, J. Bacteriol. 124:597-601, 1975), arose by a fusion of the latter plasmids, possibly by insertion of one element into another as a translocatable element. Genetic information from three other S. aureus plasmids (pK545, pSH2, and pUB101) has also been introduced into B. subtilis, although no covalently closed circular plasmid DNA was recovered.
527 citations
TL;DR: A detailed mathematical model dealing with incompatibility between autonomous homogenic plasmids and based on the assumption that the intracellular plasmid copy pool is randomized with respect to assortment during cell division is presented.
463 citations
TL;DR: This chapter is intended to survey the neutralization of animal viruses, occasional reference is made to the studies on bacterial viruses when these studies are pertinent and illuminating to the topic at hand.
Abstract: Publisher Summary Various aspects of the interaction of bacterial viruses and antibody were studied by Andrewes and Elford in England. Similar studies, as well as studies on animal viruses, were carried out in Australia by Burnet and his colleagues. One result of their extensive studies, which were summarized in great detail, was the conclusion that, with respect to their interaction with antibody, bacterial and animal viruses were basically different. Specifically, the difference resided in the stability of the union of virus and antibody, whereas bacterial viruses formed stable complexes, animal viruses formed complexes that tended to dissociate readily. The introduction of animal cell cultures as host systems greatly aided in the study of animal viruses, with respect to fewer and more readily controlled variables, and by the use of the plaque assay in enhanced quantitative reliability. In 1956, Dulbecco et al. described the interaction of two animal viruses with their respective antibodies. The results of these studies led these investigators to conclude, among other things, that animal viruses, at least the two they studied, reacted with antibodies to form complexes that did not dissociate spontaneously. This interpretation was challenged by Fazekas de St. Groth and Reid. As more animal virus-antibody systems were studied by many investigators, there seemed to be a greater accord for irreversible, rather than reversible, interaction. For this reason, in this chapter it is assumed that there are no differences between bacterial viruses, as one category, and animal viruses, as a separate category, concerning their interaction with antibodies. Rather, differences, when they exist, are considered to be related to the viruses per se. Although this chapter is intended to survey the neutralization of animal viruses, occasional reference is made to the studies on bacterial viruses when these studies are pertinent and illuminating to the topic at hand.
132 citations
TL;DR: Study of the molecular relationships between staphylococcal plasmids by DNA-DNA hybridization and restriction endonuclease cleavage supported the conclusions from genetic tests that the four Tc r and the four Sm r plasmid are essentially identical, whereas the four Cm r plasmsids are diverse.
124 citations
TL;DR: Results indicate that DNA gyrase is involved in transcription in phage promoter-dependent transcription of the trp operon in Φ80ptrp but not transcription from the authentic trp promoter.
Abstract: Nalidixic acid, novobiocin and coumermycin specifically inhibit phage promoter-dependent transcription of the trp operon in Φ80ptrp but not transcription from the authentic trp promoter. The nalidixic acid inhibition is not observed in an E. coli strain containing a nalAr mutation. These results indicate that DNA gyrase is involved in transcription.
121 citations
TL;DR: The determination of the maximal activity of carbamoylphosphate synthetase in rat liver mitochondria is reported, providing a measure of the total enzyme concentration that is about 1–1.5 mM, and results suggests that free divalent metal ion is required in the forward reaction.
Abstract: An improved purification of carbamoylphosphate synthetase I from rat liver mitochondria is described. The enzyme is essentially homogeneous with enhanced specific activity and stability. The enzyme is stable at alkaline pH in concentrated solution of salts. Kinetic studies indicate two type of inactivation, reversible and irreversible, depending on pH. The monomeric unit of carbamoylphosphate synthetase I consists of one polypeptide chain. The protein migrates in dodecylsulfate/polyaacrylamide gel as a single component corresponding to a molecular weight of about 155000. The molecular weight of the polypeptide chain determined by sedimentation equilibrium in 6 M guanidine hydrochloride containing dithioerythritol is 158000 ± 5000. The weight-average molecular weight of the native enzyme, 188000, suggests that the monomeric form is the predominant form of the enzyme, under the conditions described. Glutamine is inactive as a substrate. With ammonium, carbamoyl phosphate synthesis is optimal in the pH range 6.8–7.6. Mg2+ and Mn2+ are equally effective metal ions in the direction of carbamoyl phosphate synthesis, but excess Mn2+ is inhibitory. At less than saturating concentrations of substrate, considerable activation of the enzyme is observed when metal ions are in excess of ATP; when MgATP2− concentration is held constant at 1 mM and 10 mM, plots of v versus free Mg2+ concentration are hyperbolic, and extrapolate to zero. These results suggests that free divalent metal ion is required in the forward reaction. The apparent Km of the substrates is similar to other preparations of the enzyme. The determination of the maximal activity of carbamoylphosphate synthetase in rat liver mitochondria is reported, providing a measure of the total enzyme concentration that is about 1–1.5 mM.
The purification procedure described also provides an easy method to obtain ornithine transcarbamylase in partially purified form.
121 citations
TL;DR: In this paper, expressions for the wavelength exponents for isotropic rods, spheres, and random coils have been obtained and evaluated by representing the intraparticle interference functions, Q(Xo), with series in even powers of 1/Xo and the refractive properties with Cauchy relations.
Abstract: Synopsis The experimental parameter describing the wavelength dependence of the turbidity of solutions of macromolecules is usually the negative slope of the graph of the logarithm of optical density vs the logarithm of the in UQCUO wavelength, Xo. Such slopes are the apparent exponents of 1/b in the turbidity equation. Their values depend upon the way the destructive interference of the scattered light, the refractive index increment, and the solvent refractive index change with wavelength. In this study, expressions for the wavelength exponents for isotropic rods, spheres, and random coils have been obtained and evaluated by representing the intraparticle interference functions, Q(Xo), with series in even powers of 1/Xo and the refractive properties with Cauchy relations. Comparisons of calculated and observed exponents at wavelengths in the visible spectral region for aqueous solutions of four viruses have been made: for R17, T7, and PM2 bacteriophage, the exponents are greater than four; whereas for tobacco mosaic virus, they are less than four. The application of the turbidity relations to determine the size and molecular weight of biological macromolecules is discussed.
54 citations
01 Jan 1978
TL;DR: The anticipated advantages of these viruses for the study of “membrane biology” are to be found in their rather simple and probably stoichiometric composition with respect to proteins and nucleic acids, as well as the ease of preparing large amounts of virus material for structural work and the possibility of isolating conditional-lethal mutants that will facilitate the investigation of the morphogenetic pathways employed by these viruses.
Abstract: The several types of lipid-containing bacteriophages that have been described so far do not constitute a natural grouping. They differ from each other in many ways including host range, nucleic acid type, mode of attachment to host cells, and location of the lipid in the virion. It is, however, useful to discuss them together since they are likely to prove of immense value in the elucidation of lipid-protein interactions and the biogenesis of structures containing lipid. The anticipated advantages of these viruses for the study of “membrane biology” are to be found in their rather simple and probably stoichiometric composition with respect to proteins and nucleic acids, which is characteristic of almost all viruses, as well as the ease of preparing large amounts of virus material for structural work and the possibility of isolating conditional-lethal mutants that will facilitate the investigation of the morphogenetic pathways employed by these viruses.
42 citations
33 citations
TL;DR: PUB110 is a kanamycin resistance plasmid originally isolated in Staphylococcus aureus and introduced into B. subtilis by transformation and can replicate in a strain which is deficient in DNA polymerase I (PolI).
31 citations
TL;DR: Small polydisperse circular DNA previously identified in SV40-infected African green monkey kidney (BSC-1) cells has been isolated in pure form from uninfected cells, and the reassociation of about one third of this material indicated the presence of some repetitive chromosomal DNA sequences in spc-DNA.
TL;DR: Determination of the molecular weight of vaccinia DNA synthesized in cultures containing bromodeoxyuridine (BrUdR) demonstrated that replication proceeds in two directions.
TL;DR: It is concluded that there is a specific segregation mechanism, independent of replication, that ensures equal distribution of plasmid molecules to daughter cells during cell division.
TL;DR: This work presents a novel and scalable approaches that can be applied to the rapidly changing environment and provide real-time information about the response of the immune system to infectious disease.
TL;DR: It is concluded that the variability in estimates of the density of scrapie infectivity observed in earlier experiments has resulted from differences in the preparation of starting material, and that density gradients composed of solutions of widely different viscosities and dipole moments do not effect the buoyant density of membrane-associated scrapie virus.
Abstract: SummaryScrapie-infected mouse brain was passed through a fine mesh sieve, subjected to 900 psi, and centrifuged at 3500g. The supernate was passed through 450 nm and 220 nm Millipore filters, and centrifuged at 152,000g. The pellet was resuspended to 1/5th the original volume, sonicated, and applied to cesium chloride, sucrose, and me-trizamide gradients which were simultaneously centrifuged at 152,000g for 16 hr.Analysis of gradient fractions showed peak infectivity at a density of 1.22 g/ml in cesium chloride, 1.21 g/ml in sucrose, and 1.17 g/ml in metrizamide, with 90-95% total infectivity recovered in a well-defined band bracketing each peak titer fraction. No infectivity was observed at densities higher than 1.33 g/ml in cesium chloride, or 1.30 g/ml in sucrose and metrizamide. In each gradient the area of greatest infectivity coincided with the maximum concentration of cellular membrane vesicles and fragments, and contained between 2 and 6% of the total infective activity present in the original bra...
TL;DR: Hydroxyurea mimics the effect previously observed with pUB110, using strains carrying the conditional mutation dnaA13, and an enrichment for covalently closed circular DNA compared with chromosomal DNA was observed.
Abstract: The replication in Bacillus subtilis of the staphylococcal R plasmids pE194, pBD15, pUB110, pSA0501, and pSA2100 has been studied in the presence of hydroxyurea. In all cases, an enrichment for covalently closed circular DNA compared with chromosomal DNA was observed. In this respect, hydroxyurea mimics the effect previously observed with pUB110, using strains carrying the conditional mutation dnaA13. This mutation has been reported to affect ribonucleotide reductase (G. W. Bazill and D. Karamata, Mol. Gen. Genet. 117:19-29, 1972). An explanation for these effects is offered, together with some supporting evidence.
TL;DR: A new mutation is isolated, ups, that amplifies the suppressor activity of all the nonsense suppressors tested so far at low but not at high temperature and its effects on translational fidelity are not influenced by mutations for ribosomal drug resistance.
Abstract: We have isolated a new mutation, ups, that amplifies the suppressor activity of all the nonsense suppressors we have tested so far at low but not at high temperature. The properties of ups make it a very useful tool to improve the systems of temperature sensitive suppressors thus far described. ups maps between 25 to 27 min on the E. coli genetic map (Bachmann et al., 1976) and has no suppressor activity of its own. Its effects on translational fidelity are not influenced by mutations for ribosomal drug resistance. Thus, ups is different from ram which exhibits cooperative control of translation with other ribosomal proteins. The possible functions of ups in the cell are discussed.
TL;DR: An improved method for the isolation and identification of fecal secondary bile acids was developed and was used to analyze fecal material of rats fed a variety of bile acid-supplemented diets.
TL;DR: Investigation of the localization of small molecular weight nuclear RNA in nuclei from avian erythrocytes, bone marrow cells, reticulocytes and liver cells revealed that isolated euchromatin contained 4S, 4.5S, 5S, U1 and U2 species, while heterochromatin did only 5S and U3 RNAs.
TL;DR: Feeding the bile acid enriched diet led to decreased acidic steroid synthesis, decreased cholesterol turnover, and cholesterol balance compared to nonsupplemented controls, and Tissue cholesterol levels in the two groups were also similar.
Abstract: Sterol metabolism studies using isotopic and chromatographic techniques were carried out in: (a) control rats fed stock chow +0.1% cholesterol (control group), and (b) rats fed stock chow +0.1% cholesterol and supplemented with 0.5% sodium taurodeoxycholate (taurodeoxycholate group). Feeding the bile acid enriched diet led to decreased acidic steroid synthesis, decreased cholesterol turnover, and cholesterol balance compared to nonsupplemented controls. There were no significant differences in fecal neutral sterol output, endogenous neutral sterol output, or cholesterol absorption between bile acid fed animals and controls. Tissue cholesterol levels (liver, plasma, and bile) in the two groups were also similar.
TL;DR: Antisera prepared by immunization with conjugates of 4-dimethylamino-2,2-diphenylvaleric acid—bovine serum albumin have been characterized in their reactivity with methadone, l -α-acetylmethadol, and with their major metabolites.
01 Jan 1978
TL;DR: Results showed that both (24R and 24S)-27-nor-24-methyl-3alpha,7alpha-dihydroxy-5beta-cholestan-26-oic acids were not metabolized by the liver and were excreted unchanged as their taurine and glycine conjugates whereas 27-nor -nor-3 alpha, 7alpha- dihydrox-5 beta- cholestans- 26-Oic acid was
TL;DR: A method is described for estimating early mouse IgG antibodies to the dinitrophenyl (DNP) determinant in absolute weight units by conversion of the losses in C fixing potencies to weight units ofmouse IgG anti-DNP by interpolation on the calibration curve.
07 Aug 1978
TL;DR: The review of literatures of cases of cutaneous mucormycosis and experimental studies by subcutaneous inoculation of various strains belonging Mucoraceae on the nude mice were made and the clinical, histological and mycological problems were discussed.
Abstract: The review of literatures of twenty eight cases of cutaneous mucormycosis and of ninety one cases of entomophthoramycosis was made. The experimental studies by subcutaneous inoculation of various strains belonging Mucoraceae on the nude mice were also added.1) Cutaneous mucormycosis in the world literatures were very rare and only three cases were reported in Japan until 1977. The etiological agents of cutaneous mucormycosis were fungi belonging Mucoraceae including M. corymbifera, M. ramosus, M. pusillus, R. arrhizus, R. rhizopodiformis, A. ramosa etc. The cases in Japan were caused by R. ramosus (2 cases) and Rhizopus sp.. The main predisposing diseases of cutaneous mucormycosis were diabetes mellitus, leucemia andot her malignant tumors including lymphomas.Experimentally, the authors could make the cutaneous lesions on the skin of the nude mice by inoculating various strains of Mucoraceae including R. stolonifer, R. arrhizus, M. pusillus, A. ramosa, A. corymbifera. The emulsion containing spores 106-8/ml in concentration was inoculated subcutaneously by B. C. G. needle on the back of the mice. The inoculated area were covered by Drenison-tape (plastic film containing corticosteroid) with the method of occlusive technique. After 4 to 10 days erythema, swelling and subcutaneous nodules on the inoculated skin. Histologically, the nonseptated, wide, branching hyphae were observed in the inflammatory lesions of the dermis and of the epidermis. Spores were not seen in tissue specimens. The perifungal tissue reaction was very slight.2) Sensitivity tests of 17 strains of fungi belonging Mucoraceae against various antimycotics: trichlomazol, 5-FC, griseofulvin, merzonine, nystatine, amphotericine B, were made. Amphotericine B, trichlomazol and merzonine showed good inhibitory effect in vitro, while inhibitory effect of 5-FC was very poor.3) Entomophthoramycosis is a disease usually found in the tropical countries, such as countries in African continent, Indonesia, India and countries in South American continent. No cases were found in Japan until 1977. Entomophthoramycosis is divided into two groups: Entomophthoramycosis basidiobolae (subcutaneous phycomycosis) and Entomophthoramycosis conidiobolae (rhinophycomycosis). The clinical, histological and mycological problems were discussed.