| characterization of lambdapola transducing phages; effective expression of the e. coli pola gene. | lambdapola phages carrying the pola gene in either orientation were isolated and characterised by genetic tests and by assay of the pola gene product after infection of e. coli or induction of lysogens. lytic infection gave consistently better amplification of dna polymerase i than that obtained by induction of a lysogen. optimal amplification of dna polymerase i was not achieved from the pl promoter of cro-phages, but some advantages accrued when the pola gene was oriented for transcription fro ... | 1979 | 159999 |
| characterization of the dnaa, gyrb and other genes in the dnaa region of the escherichia coli chromosome on specialized transducing phages lambda tna. | specialized transducing phages lambda tna (tryptophanase) harboring chromosomal dna and genetic markers from the dnaa region of the escherichia coli chromosome were isolated. transductional analysis showed that some of these tnaa transducing phages carry two genes important in dna replication, namely the dnaa gene (initiation of chromosome replication) and the gyrb gene (subunit b of dna gyrase), formerly designated cour. the following clockwise order of genetic markers was found: uhp, gyrb, dna ... | 1979 | 160000 |
| uvm mutants of escherichia coli k12 deficient in uv mutagenesis. ii. further evidence for a novel function in error-prone repair. | uvm mutants of escherichia coli k12 selected for defective uv reversion induction have previously been reported to differ considerably from the uv-reversion-less reca and lexa mutants with regard to survival or mutagenic response to uv, x-rays and alkylating agents. in the present study, the phenotypic characterization of uvm mutants was extended to investigate several cellular processes which also may be related to or involved in uv mutagenesis. like reca and lexa mutations, the uvm mutations e ... | 1979 | 160001 |
| the influences of a lambda prophage on the growth rate of escherichia coli. | a lambda prophage increases the competitive ability of e. coli k12 in a glucose-limited chemostat. this phenomenon does not involve the lambdarex gene. expression of the lambdarex gene conditionally decreases fitness in two ways: (1) it causes malt- but not malt+ lysogens to be at a selective disadvantage in competition with non-lysogens. (2) during adaptation to slow, glucose-limited chemostat growth from rapid, glucose-excess flask growth, expression of the lambdarex gene transiently decreases ... | 1978 | 160003 |
| nucleotide sequence of a secondary attachment site for bacteriophage lambda on the escherichia coli chromosome. | the nucleotide sequence of a secondary attachment site for bacteriophage lambda was determined in a region near the rrnb gene at 88 min on the e. coli chromosome. the sequence has a 8 base pair interrupted homology gct tttta to the common core of the primary attachment site (attb) and the corresponding phage sequence (attp). the site of crossover during integration lies probably between nucleotides -3 and +1. the flanking regions have no obvious homology to the arms of either attp or attb. | 1979 | 160033 |
| the induction of a mutant prophage lambda in escherichia coli: a rapid screening test for carcinogens. | | 1979 | 160128 |
| absence of ferric enterobactin receptor modification activity in mutants of escherichia coli k-12 lacking protein a. | | 1979 | 160226 |
| specificity of the bacteriophage lambda n gene product (pn): nut sequences are necessary and sufficient for antitermination by pn. | we have cloned the nutr site together with the tr1 site of bacteriophage lambda in the e. coli galactose operon to examine whether the lambda promoter sequences pr and pl are involved in the recognition specificity of the lambda n gene product (pn). we first constructed a derivative of plasmid pbr322 in which the expression of the tetracycline genes (tet) is controlled by the gal promoter (pgal). this new plasmid contains a unique hind iii site between pgal and tet into which the nutr and tr1 si ... | 1979 | 160286 |
| the sensitivity of staphylococcus aureus 79 and 80, and escherichia coli 95 to sodium salicylate, nicotinaldehyde singly, and in combination with nicotinic acid or nicotinamide. | minimum bactericidal concentrations of salicylate, nicotinaldehyde singly, and in combination with nicotinic acid, or nicotinamide were determined for staphylococcus aureus 79 and 80, and escherichia coli 95, at inocula of 10(7)--10(2). the bactericidal dose of salicylate was affected markedly by the inoculum size. the bactericidal dose of nicotinic acid, or nicotinamide was affected only slightly by the size of the inoculum. escherichia coli 95 was least affected by the inoculum size. nicotinal ... | 1979 | 160304 |
| inhibition of e coli atpase activity by a troponin component, tn-i, and by mitochondrial atpase inhibitor. | the enzymic activity of mg2+- or ca2+-stimulated atpase from escherichia coli was inhibited by one of the troponin components, tn-i, and by mitochondrial atpase inhibitor (f1-inhibitor). the inhibitory ability of component tn-i against mg2+-stimulated atpase activity was lost after digestion of component tn-i with trypsin. the mg2+-stimulated atpase activity inhibited by component tn-i was completely restored by the addition of another troponin component tn-c. | 1979 | 160325 |
| [effect of the dose of ptsi- and ptsh-genes on carbohydrate transport and regulation of lac-operon activity in escherichia coli k-12]. | phage mu-1 cts61 was used for transposition of pts1 and ptsh genes. the received f'-factors auf2 and auf3 carry short fragments of the bacterial chromosome. merodiploid strains with double pts genes were selected in sexduction crosses with the appropriate reca recipients. effect of the gene dose was not registered in pts+/pts+ strains in the case of accumulation of the substrates of the phosphoenolpyruvate-dependent phosphotransferase system (pts) and in the case of bacterial growth in the prese ... | 1979 | 160355 |
| a rightward promoter to the left of the att site of lambda phage dna: possible participant in site-specific recombination. | the binding has been studied of escherichia coli rna-polymerase to the fragments of lambda dna obtained by digestion with restriction endonucleases bsui, hindiii, bamhi, ecori and hindii + iii. there are at least six sites of rna-polymerase binding in the b2-region. in vitro transcription of those bsui-fragments of the b2-region which contain six binding sites is rightward. therefore, the fragments contain promoters rather than mere rna-polymerase binding sites. one of the promoters of the b2 re ... | 1979 | 160359 |
| response to a metal ion-citrate complex in bacterial sensing. | salmonella typhimurium responds chemotactically to gradients of divalent cations in the presence of citrate ions. the actual chemoeffector is the citrate-metal ion complex, which acts as an attractant. citrate (which is also a chemoeffector for salmonella) and the citrate-metal ion complex are recognized by different receptors. the response of salmonells, which can transport citrate through its membrane, is quite different than that of escherichia coli, which cannot. | 1979 | 160411 |
| cloning and physical mapping of the dnaa region of the escherichia coli chromosome. | the dnaa gene of escherichia coli k-12, supposedly present in the deoxyribonucleic acid (dna) of specialized transducing phase lambda i21 dnaa-2, was cloned onto plasmid pbr322. the new plasmid was named pmcr501. physical analyses of dnas of lambda i21 dnaa-2 and pmcr501 revealed the following. the lambda i21 dnaa-2 dna retained the delta sr i lambda 1-2 and ninr5 deletions and imm21 substitution which were originally present in the parental phage. the size reduction was compensated for by the i ... | 1979 | 160412 |
| conditionally lethal amber mutations in the dnaa region of the escherichia coli chromosome that affect chromosome replication. | three amber mutations, dna-801, dna-803, and dna-806, were isolated by localized mutagenesis of the dnaa-oric region of the chromosome from an escherichia coli strain carrying temperature-sensitive amber suppressors. when the mutations were not suppressed at 42 degrees c, the cells did not grow and dna synthesis was arrested. they were very closely linked to each other and to the dnaa46 mutation. the mutant phenotype of each strain was converted to the wild type by infecting the mutants with spe ... | 1979 | 160413 |
| inactivation of prophage in ultraviolet-irradiated escherichia coli: dependence on reca gene activity. | the fate of the prophage part of the lysogenic chromosome was followed in the course of post-ultraviolet incubation. for this purpose, lambda ci857 ind prophage, which can be induced by heat but not by ultraviolet light, was used. the prophage, intially more resistant than its repair-proficient host cell, was rapidly inactivated. this inactivation was not caused by the impaired capacity of irradiated cells to support growth of the phage. over the entire dose range tested, little, if any, sensiti ... | 1979 | 160414 |
| loss of rac locus dna in merozygotes of escherichia coli k12. | dna-dna hybridization was used to demonstrate that the substituted dna in the bacteriophage lambda rece (formerly called lambda reverse) is homologous to dna at the rac locus in escherichia coli. strains that are rac- do not contain appreciable amounts of this dna, and it is lost from a rac+ episome (f' 123) after transmission to a rac- recipient. this is consistent with the proposal that the rac locus contains a cryptic prophage (low, 1973). | 1979 | 160489 |
| cloning the trpr gene. | in escherichia coli, the structural gene for purine nucleoside phosphorylase, deod, is subject to insertional inactivation by prophage lambda. from one such secondary site lambda lysogen, strain sp265, one may isolate deletions that remove all or part of the trpr gene and other genes in the deo-thr sector of the e. coli chromosome. specialized transducing phages harboring serb+ and trpr+ were liberated following induction of sp265. all such phages were n-defective, bio-type pseudolysogens whose ... | 1979 | 160491 |
| transcription and membrane attachment of bacteriophage lambda dna in the absence of n function in the e. coli sua 1 mutant. | in the polarity suppressor strain psua 1, we observe a partial n independence of both transcription and dna-membrane attachment for a lambda nn mutant. these results, in agreement with the genetical data reported by dambly et al. (1976), suggest that the n product and rho factor are involved in the same process but may not interact directly. | 1979 | 160492 |
| increased expression of a eukaryotic gene in escherichia coli through stabilization of its messenger rna. | the expression of a cloned eukaryotic gene [catabolic dehydroquinase (3-dehydroquinate hydro-lyase, ec 4.2.1.10) (qa-2+) from neurospora crassa] is dramatically increased (as much as 100-fold) in escherichia coli strains deficient in polynucleotide phosphorylase (pnp) (polynucleotide: orthophosphate nucleotidyltransferase, ec 2.7.7.8) and rnase i (rna). the increased expression is controlled primarily by the absence of polynucleotide phosphorylase and appears to be specific for the eukaryotic ge ... | 1979 | 160556 |
| gene expression of an escherichia coli ribosomal rna promoter fused to structural genes of the galactose operon. | the promoter region of the rrnb ribosomal rna gene of escherichia coli has been ligated within the epimerase gene (gale) of the galactose operon in a lambda phage vector. the recombinant lambda phage has been characterized by restriction mapping and assays of both galk (galactokinase) gene activity and galactose messenger rna hybridization. in such lyosgens, expression of the fused galactose operon occurs as a function of growth rate in a manner characteristic of ribosomal rna gene expression an ... | 1979 | 160557 |
| dna from recombinogenic lambda bacteriophages generated by arl mutant of escherichia coli is cleaved by single-strand-specific endonuclease s1. | when propagated on arl strains (a subclass of escherichia coli hyper-rec mutants), lambda "red-" duplication phages accumulated an enhanced potential for recombination. the physical properties of the recombinogenic phages thus obtained ("arl-" phages) were similar to those of phages grown on arl+ bacteria. however, arl- phage dna was cleaved by endonuclease s1 under conditions such that the nuclease is specific for single-stranded dna;dna from control phages was s1-resistant. the number of s1 si ... | 1979 | 160560 |
| identification of the lexa gene product of escherichia coli k-12. | the escherichia coli lexa gene encodes a product important in induction of the reca gene and the expression of various cellular functions, including mutagenesis and prophage induction. as a start in a biochemical analysis of the lexa function, a family of lambda transducing phages carrying lexa+, lexa3, lexa3 spr-54, and lexa3 spr-55 alleles of the lexa gene was isolated and characterized. polypeptides synthesized by these phages were examined. lambdalexa+ made a distinctive protein 24 kilodalto ... | 1979 | 160562 |
| the delta subunit of escherichia coli dna polymerase iii holoenzyme is the dnax gene product. | the delta subunit of dna polymerase iii holoenzyme has been purified extensively with an assay for phi x174 dna synthesis using core (pol iii) and beta and gamma subunits. either the purified delta subunit or the purified dna polymerase iii holoenzyme can complement a defective enzyme fraction from the conditional replication mutant sg133 described by sevastopoulos et al. [sevastopoulas, c.g., wehr, c.t. & glaser, d. a. (1977) proc. natl. acad. sci. usa 74, 3485-3489]. it has been established by ... | 1979 | 160563 |
| gene for the rna polymerase sigma subunit mapped in salmonella typhimurium and escherichia coli by cloning and deletion. | the genes for the rna polymerase sigma subunit (rpod) and dna primase (dnag) of salmonella typhimurium have been cloned into lambda vectors. combined restriction, deletion and functional analysis of the cloned fragment allows us to map the genes precisely on the fragment, establishes the direction in which rpod is transcribed, and reveals the existence of at least one new gene in the vicinity. a closely homologous, smaller fragment of escherichia coli dna, also cloned into lambda, contains rpod ... | 1979 | 160566 |
| operon-specific regulation of ribosomal protein synthesis in escherichia coli. | we have cloned a dna fragment harboring the genes for ribosomal proteins l2, l4, and l23 on a plasmid vector that contains a lac operator and promoter. the cloned ribosomal protein genes are now under the control of lacop. addition of a lac inducer to these cells results in a specific 5- to 10-fold increase in the synthesis of the proteins corresponding to the cloned genes. within 10 min of this induction, the synthesis of ribosomal proteins s3, s19, l3, l16, l22, and l29 stops almost completely ... | 1979 | 160567 |
| inhibition of e. coli l-asparaginase by reaction with 2,3-butanedione. chemical modification of arginine and histidine residues. | the inactivation of e. coli asparaginase by 2,3-butanedione studied with l-asparagine and diazooxonorvaline as substrates obeys pseudo first order kinetics. activity losses are linear with respect to arginine and histidine modification, with complete inactivation being correlated with alteration of one arginine and one histidine per subunit. the rate of inactivation of the enzyme was reduced in the presence of competitive inhibitors like l-2-amino-2-carboxyethane-sulfonamide. under comparable co ... | 1979 | 160698 |
| [quantitative comparison of ribosome binding sites of twelve nucleotide sequences from escherichia coli (rna- and dna phages) based on triplet patterns (author's transl)]. | the molecular structure of ribosome binding sites of ten phage genes and two messengers of escherichia coli were compared concerning the signation parts which are presumably used by ribosomes for recognition and binding. with a simple calculation based on triplet patterns sofar unknown agreements between all of these sequences were found. in several cases it was shown that agreements between old sequences are easier recognizable if the purine- and pyrimidine bases are put into the triplets inste ... | 1979 | 160703 |
| ter mutation and susceptibility to phi x174 phage in e. coli k12. | | 1979 | 160794 |
| regulation of the in vitro synthesis of e. coli ribosomal protein l12. | | 1979 | 160796 |
| novel iron uptake system specified by colv plasmids: an important component in the virulence of invasive strains of escherichia coli. | the enhanced virulence of invasive strains of escherichia coli carrying colv plasmids was shown to be due to a novel plasmid-mediated iron uptake system. possession of a colv plasmid conferred strong selective advantage on the host bacterial strain in experimental infections unless excess iron was administered in the inoculum. moreover, supplementation of defined minimal medium with transferrin to complex available iron caused marked limitation of the growth of plasmid-free strains but had no ef ... | 1979 | 160892 |
| effect of experimental magnetic storm on the production of lambda phage. | 1. sharp fluctuation of the intensity of the vertical component of the mf amounting to +/- 0.1 oe changing the sign over each 3 min causes variability of both lysogenic and indicator strains of e. coli. this testifies to an extremely low threshold of their magnetic susceptibility and to biological importance of fluctuations of natural parameters of the geomagnetic field as an ecological factor of the environment. 2. a change in the intensity of the vertical component of the mf, not any higher th ... | 1979 | 160920 |
| [proton translocating atpase of escherichia coli (author's transl)]. | | 1979 | 160921 |
| identification of transfer rna suppressors in escherichia coli. i. amber suppressor su+2, an anticodon mutant of trna2gln. | | 1979 | 160949 |
| identification of transfer rna suppressors in escherichia coli. ii. duplicate genes for trna2gln. | | 1979 | 160950 |
| [clinical experience of cefoxitin in the field of obstetrics and gynecology (author's transl)]. | cefoxitin was given to the 7 patients of infections in the field of obstetrics and gynecology, and the following results were obtained: 1) the clinical response was excellent in 2 patients, good in 4 and poor in 1 patient with the efficacy rate of 85.7%. out of the 4 patients resistant to the previous therapy with other antibiotics, 3 patients responded to cefoxitin, and all the 3 patients of anaerobic infections responded satisfactorily to cefoxitin. 2) microorganisms isolated were 2 strains ea ... | 1979 | 160956 |
| [phage-dependent beta-galactosidase synthesis by escherichia coli cells]. | | 1979 | 160977 |
| [biological characteristics of enteropathogenic escherichia coli from serological groups 0142 and 0159 isolated in leningrad]. | | 1978 | 161089 |
| phosphorylation of streptozotocin during uptake via the phosphoenolpyruvate: sugar phosphotransferase system in escherichia coli. | mutants of escherichia coli k-12, staphylococcus aureus, and bacillus subtilis defective in the general components (enzyme i, or hpr, or both) of the phosphoenolpyruvate:sugar phosphotransferase system are shown to be resistant to the antibiotic streptozotocin. it is shown here, employing 32p-labeled phosphoenolpyruvate, that wild-type cells of e. coli phosphorylate streptozotocin, whereas with a phosphotransferase system-defective mutant of e. coli the drug is recovered in an unaltered, free fo ... | 1979 | 161156 |
| the fate of phage lambda dna in lambda-infected minicells. | the fate of phage lambda dna in lambda-infected escherichia coli minicells harboring the plasmid cole1, and in plasmid-free minicells, were studied. binding of lambda dna to the minicell membrane, and formation of the supercoiled covalently-closed circular structure has been demonstrated. phage infection abolishes plasmid dna synthesis. only a very slight, non-replicative lambda dna synthesis occurs, soon after infection. this synthesis is associated with fragments of lambda dna arising during, ... | 1979 | 161175 |
| site-specific mutagenesis using synthetic oligodeoxyribonucleotide primers: i. optimum conditions and minimum ologodeoxyribonucleotide length. | a synthetic oligodeoxyribonucleotide mismatched at a single nucleotide to a specific complementary site on wild-type circular phi x174 dna can be used to produce a defined point mutation after in vitro incorporation into closed circular duplex dna by elongation with dna polymerase and ligation followed by transfection of escherichia coli (hutchison et al., 1978; gillam et al., 1979). the present study is an investigation of the optimum conditions required for the oligodeoxyribonucleotide-primed ... | 1979 | 161245 |
| site-specific mutagenesis using synthetic oligodeoxyribonucleotide primers: ii. in vitro selection of mutant dna. | a method for the in vitro selection of mutant dna has been devised as an adjunct to the recently developed method for the use of short enzymatically-synthesized oligodeoxyribonucleotides of defined sequence as site-specific mutagens for circular dna. the selection method uses the mutating oligodeoxyribonucleotide as a primer for escherichia coli dna polymerase i (large fragment) under conditions where there is preferential interaction with mutant dna template. after ligation using t4 dna ligase, ... | 1979 | 161246 |
| a conditionally lethal mutation of escherichia coli affecting the gene coding for ribosomal protein s2 (rpsb). | | 1979 | 161328 |
| differential toxicities of mercury to bacteria and bacteriophages in sea and in lake water. | mixtures of anionic hgcl3-/hgcl4(2)-complexes were less toxic to terrestrial bacteria (erwinia herbicola, agrobacterium tumefaciens), to marine bacteria (acinetobacter sp., aeromonas sp.), and to bacteriophages (phi 11 m 15 of staphylococcus aureus and p1 of escherichia coli) than were equivalent concentrations of hg as cationic hg2+. the toxicity of 1 ppm hg to a. tumefaciens. aeromonas sp., and phi 11 m 15 was less in seawater than in lake water. inasmuch as the hg-cl species are formed in env ... | 1979 | 161510 |
| enterobactin and virulence of escherichia coli in pyelonephritis. | | 1979 | 161566 |
| complementation analysis of eleven tryptophanase mutations in escherichia coli. | nine independent mutants deficient in tryptophanase activity were isolated. each mutation was transferred to a specialized transducing phage that carries the tryptophanase region of the escherichia coli chromosome. the nine phages thus produced, and a tenth carrying a previously characterized tryptophanase mutation, were used to lysogenize a bacterial strain harbouring a mutation in the tryptophanase structural gene and also a suppressor of polarity. in no case was complementation observed; we c ... | 1979 | 161572 |
| inhibitory properties of endogenous subunit epsilon in the escherichia coli f1 atpase. | | 1979 | 161698 |
| [dna sequence encoding the signal peptide of the lambda receptor in e. coli k 12]. | a 181 base pairs dna fragment from e. coli k 12 has been sequenced. this allows determination of the sequence of the signal peptide of the precursor for the lambda receptor, an outer membrane protein. | 1979 | 161974 |
| significance of phosphofructokinase allostery: the escherichia coli isozymes. | | 1979 | 162196 |
| endotoxin fever in the newborn kitten. the role of prostaglandins and monoamines. | in 5--10 day-old kittens at thermoneutral environmental temperature cerebroventricular injections of 10 microgram serotonin or noradrenaline caused hyperthermia and hypothermia, respectively. central injections of 20 and 200 ng prostaglandin e1 induced hyperthermia. monophasic fever followed the cerebroventricular injections of 0.2 or 0.002 microgram e. coli endotoxin, both in thermoneutral and moderately cool environments. in kittens pretreated with para-chlorophenylalanine (pcpa) the endotoxin ... | 1979 | 162315 |
| augmented venous return: protection of the ischemic myocardium during endotoxemia. | the effects of gram-negative endotoxin (escherichia coli 4 mg/kg) induced myocardial failure in the pentobarbital-anesthesized dog were examined by monitoring its influence on coronary and systemic hemodynamics and correlating these results with myofibrillar atpase activity. an identical series of studies was performed incorporating a femoral-femoral arterial-venous shunt to augment venous return. over a five-hour period, gram-negative endotoxemia was associated with a progressive fall in arteri ... | 1979 | 162474 |
| isolation and characterization of nondefective transducing lambda bacteriophages carrying fla genes of escherichia coli k-12. | in escherichia coli k-12, 11 fla genes and a hag gene are located between his and uvrc, making two clusters at map positions 42.5 and 43.0 min. nondefective transducing lambda phages for these genes were isolated. low-frequency-transducing donors were constructed starting from lysogens of lambda ci857 in which the prophage is integrated at a secondary attachment site at 44 min on the e. coli map. two strategies were used to delete the region between the prophage and the fla genes. deletion mutan ... | 1977 | 162537 |
| pathophysiology and treatment of escherichia coli enteric infections in calves. | | 1975 | 162618 |
| classification of enterotoxins on the basis of activity in cell culture. | two cell culture systems were used in a study of the biological properties of several bacterial enterotoxins in vitro. by means of one model, in which hela cell monolayers were used, cytotoxic effects, interms of detachment of cells from a glass surface due to cell death, were assayed. by means of the second model, activation of the adenyl cyclase-cyclic adenosine 3', 5'-monophosphate (amp) system, in terms of increased steroidogenesis by y-1 adrenal cells (an effect which we have termed cytoton ... | 1975 | 162926 |
| cell septation and the synthesis of catabolite repressible enzymes in escherichia coli. | | 1975 | 163090 |
| effect of polymyxin b on liposomal membranes derived from escherichia coli lipids. | the specificity of the action of polymyxin b was studied using liposomes as a model membrane system. liposomes prepared from total lipids of gram-negative bacteria escherichia coli, a mixture of purified e. coli phosphatidylethanolamine and cardiolipin and a mixture of phosphatidylethanolamine and phosphatidylglycerol, were extemely sensitive to polymyxin while those prepared from lipids of gram-positive bacteria streptococcus sanguis, lipids of sheep erythrocyte membranes, mixtures of egg lecit ... | 1975 | 163098 |
| deoxyribonucleic acid polymerase iii of escherichia coli. characterization of associated exonuclease activities. | purified dna polymerase iii has two distinct exonuclease activities: one initiates hydrolsis at the 3 termini, and the other at the 5 termini of single-stranded dna. both exonucleases have the same relative mobility on polyacrylamide gels as the polymerase activity. molecular identity of the three activities is further indicated by their comparative rates of thermal inactivation and their sensitivity to ionic strength. the 3-5 exonuclease activity hydrolyzes only single-standed dna. the rate of ... | 1975 | 163228 |
| role of metal ions in escherichia coli alkaline phosphatase. a study of the metal-water interaction by nuclear relaxation rate measurements on water protons. | the binding of metal to alkaline phosphatase from escherichia coli and the binding of water and orthophosphate to the me-2+-enzyme binary complex have been examined by water proton relaxation rate (prr) measurements. titration of the three paramagnetic metals, mn2+, cu2+, and co2+, into apoalkaline phosphatase and the titrations of apoenzyme into metal have been carried out. analysis of the spin-lattice relaxation rates for these titrations and of scatchard binding curves derived from these resu ... | 1975 | 163241 |
| purification and properties of stringent factor. | the stringent factor from escherichia coli is the product of the rela locus. it is the enzyme that catalyzes the synthesis of pppgpp and ppgpp eliciting a pyrophosphate transfer from atp to the 3'--oh of gtp (or gdp). this protein is responsible for the synthesis of pppgpp and ppgpp in stringent strains in response to an amino acid starvation. in vitro it catalyzes the synthesis of these guanosine compounds in either a ribosome-dependent reaction that requires a particular conformation of the ri ... | 1975 | 163249 |
| aspartokinase i-homoserine dehydrogenase i of escherichia coli k12 (lambda). activation by monovalent cations and an analysis of the effect of the adenosine triphosphate-magnesium ion complex on this activation process. | the dehydrogenase activity of the aspartokinase i-homoserine dehydrogenase i complex isolated from escherichia coli k12 is subject to a cooperative activation by k+ or rb+, which is characterized by a hill coefficient of approximately 2. ionic strength has little effect on the hill coefficient for this activation process; however, high ionic strength appears to increase the enzyme's affinity for k+ and decrease its affinity for rb+. the vmax of the k+-activated dehydrogenase is greater than that ... | 1975 | 163250 |
| structural determination of the sialic acid polysaccharide antigens of neisseria meningitidis serogroups b and c with carbon 13 nuclear magnetic resonance. | the application of 13-c nuclear magnetic resonance to the analysis of some sialic acid-containing meningococcal polysaccharide antigens is described. complete assignments of the spectra of both the native serogroup b and the de-o-acetylated serogroup c polysaccharides have been made. these assignments were based on the corresponding data for some related monomers (sialic acid and its alpha-and beta-methylglycosides) and on supportive chemical evidence. the data indicate that the serogroup b poly ... | 1975 | 163259 |
| repair of damage induced by ultraviolet radiation in mutator t-1 escherichia coli transductants. | | 1975 | 163268 |
| modulation of in vivo antibody responses by cholera toxin. | treatment of mice with an exotoxin (0.01 mug to 1.0 mug) purified from vibrio cholerae culture filtrates markedly influenced the immune response to sheep erythrocytes (srbc) and the escherichia coli lipopolysaccharide (lps). simultaneous administration of the toxin (ct) with antigen resulted in a delayed appearance of antibody plaque-forming cells (pfc) during the first few days after immunization, followed by a marked enhancement of both igm and igg pfc. the secondary immune response to srbc wa ... | 1975 | 163279 |
| temporal appearance of bacteriophage t4-modified valyl trna synthetase in escherichia coli. | bacteriophage t4-induced modification of escherichia coli vlayl-trna synthetase (ec 6.1.1.9) requires: synthesis of a phage-gene specified tau factor, addition of the factor to host valyl-trna synthetase to produce a urea-stable enzyme, and interaction of the modified enzyme with trna to produce a more rapidly sedimenting valyl-trna synthetase activity on sucrose density gradients. this report demonstrates that the coincident, chloramphenicol-sensitive appearance of urea-stable and rapidly sedim ... | 1975 | 163351 |
| replication of polyoma dna in isolated nuclei. v. complementation of in vitro dna replication. | nuclei from polyoma-infected 3t6 fibroblasts elongate in vitro the progeny strands of the replicative intermediates of polyoma dna. when high concentrations of such nuclei were incubated, short dna fragments were formed and subsequently added onto growing progeny strands. when nuclei were repeatedly washed with buffer containing detergent and then incubated at low concentrations. dna synthesis was decreased. in particular, the joining process was reduced, resulting in an accumulation of short dn ... | 1975 | 163354 |
| early events after infection of escherichia coli by bacteriophage t5. induction of a 5'-nucleotidase activity and excretion of free bases. | thymine-containing compounds, produced degradation of escherichia coli dna after infection of the cells with bacteriophage t5, did not accumulate in the cell but were excreted into the medium as the dna was degraded. the ultimate degradation product was extracellular thymine that was not reutilized when t5 dna synthesis began. this excretion of thymine may have been due in part to the induction of 5'-nucleotidase activity within 3 min after t5 infection. the level of this activity reached a maxi ... | 1975 | 163355 |
| inactivation of viruses and bacteria by ozone, with and without sonication. | selected organisms with public health significance were placed in a reaction chamber for treatment by ozonation, by ozonation and sonication, by sonication, or by sonication during oxygenation. vesicular stomatitis virus, encephalomyocarditis virus, gdvii virus, staphylococcus aureus, pseudomonas fluorescens, salmonella typhimurium, enteropathogenic escherichia coli, vibrio cholerae, and shigella flexneri were inactivated by treatment with ozone. when microorganisms were suspended in phosphate-b ... | 1975 | 163616 |
| dna-binding proteins from novikoff hepatoma cells. | in 0.05 m nacl, 6-8% of the total soluble proteins from novikoff hepatoma cells bind rapidly and reversibly to columns containing either heterologous or homologous dna adsorbed to cellulose. these proteins can be eluted by buffer containing 2.0 m nacl. 0.5-1% of the total protein exhibits a 7-17-fold preference for rat dna over escherichia coli dna. 1-1.5% of the proteins bind dna so strongly that elution cannot be effected by 4.0 m nacl but can be accomplished by deoxyribonuclease i treatment o ... | 1975 | 163652 |
| a comparison of the effects of daunomycin and adriamycin on various dna polymerases. | the effects of the anthracycline antiboties, daunomycin and adriamycin, on the dna-directed activities of dna polymerases from murine sarcoma virus, rat liver (high-molecular-weight species), escherichia coli, and micrococcus luteus were determined. under all conditions tested, these compounds had greater inhibitory effect against the viral polymerase than against cellular polymerase. the inhibition of murine sarcoma virus dna polymerase by daunomycin was competitive with respect to dna. for vir ... | 1975 | 163690 |
| escherichia coli enterotoxin: stimulation of adenylate cyclase in broken-cell preparations. | the enterotoxin from cell-free filtrates of the enteropathogenic escherichia coli strain p-263 was found to stimulate adenylate cyclase activity in broken-cell preparations from myocardial tissue. particulate and detergent-solubilized fractions from cat heart were incubated with enterotoxin and assayed for adenylate cyclase activity. adenylate cyclase activity was stimulated by enterotoxin; the extent of stimulation was proportional to the concentration of enterotoxin. the data demonstrate that ... | 1975 | 163792 |
| isolation of a metabolite capable of differentially supporting the growth of nicotinamide adenine dinucleotide auxotrophs of escherichia coli. | a compound, isolated from the culture fluid of a nadc auxotroph of escherichia coli grown in a minimal medium, supports the growth of both a nada and a nadb mutant. this metabolite exhibits an ultraviolet light absorption spectrum and a mass spectrum, different from quinolinic acid. this compound may be the precursor of quinolinic acid, an intermediate in the biosynthesis of nicotinamide adenosine dinucleotide. | 1975 | 163810 |
| isolation and characterization of catabolite-resistant mutants in the d-serine deaminase system of escherichia coli k-12. | two classes of d-serine deaminase (dsdase)-specific secondary mutants of escherichia coli k-12 were isolated from a dsdase low constitutive nonhyperinducible mutant as types which could grow in the presence of both d-serine and glucose. these strains contain cis dominant, nonsuppressible mutations in the dsdo (operator-initiator) region. in the first class of mutants (e.g., fb4010), dsdase synthesis is completely insensitive to catabolite repression, and synthesis occurs at a high constitutive r ... | 1975 | 163811 |
| effect of tsl mutations in decreasing radiation sensitivity of a reca- strain of escherichia coli k-12. | it has been shown previously that the radiation sensitivity of lexa- strains of escherichia coli k-12 can be suppressed by thermosensitive mutations (designated tsl) that are closely linked to the lexa locus and are thought to be intragenic suppressors of lexa mutations (mount et al., 1973). when a reca mutation is crossed into a suppressed tsl- strain, the extreme radiation sensitivity usually conferred by a reca mutation is decreased, but there is no detectable change in genetic recombination ... | 1975 | 163812 |
| kinectics of beta-galactosidase synthesis in escherichia coli at 5 c. | the defect in protein synthesis that is observed in escherichia coli after transfer to low temperature was studied. for the enzyme beta-galactosidase, the elongation reactions of transcription and translation can take place slowly but normally at 5 c. the time necessary to complete the coupled synthesis of the beta-galactosidase messenger ribonucleic acid and polypeptide chain was found to be about 80 min at 5 c. from this result and from the known length of the beta-galactosidase monomer, it is ... | 1975 | 163816 |
| activation of transcription by guanosine 5'-diphosphate,3'-diphosphate, transfer ribonucleic acid, and novel protein from escherichia coli. | a protein factor tfms) that is required for ppgpp to stimulate rna synthesis has been purified from an eluate of crude ribosomes. tfms also has the capacity to stimulate rna synthesis without ppgpp present. under standard conditions the action tfms and ppgpp requires uncharged trna. tfms and ppgpp act at inhibition to promote the formation of rifampicin-resistant or polytri)-resistant preinitiation complexes. in the presence of rifampicin or poly(ri), trna is no longer required. with lambdah80dl ... | 1975 | 163822 |
| antagonism of the antibacterial action of some penicillins by other penicillins and cephalosporins. | there are many examples of two penicillins acting synergistically, usually by one competitively inhibiting beta-lactamase, thus protecting the other from inactivation. there are few reports on penicillins antagonizing each other. eight strains of three genera (proteus, escherichia, pseudomonas) isolated at boston city hospital or institut pasteur, paris, showed antagonism of carbenicillin or ampicillin by cephaloridine, cloxacillin, or 6-aminopenicillanic acid. broth dilution tests showed that w ... | 1975 | 163847 |
| travelers' diarrhea and toxigenic escherichia coli. | in a group of 133 united states students studied for 18 days after arriving in mexico, diarrhea developed in 38 (29 per cent). diarrhea rarely began before the fourth day, and the mean onset was 13 days after arrival. symptoms lasted an average of 3.4 days but persisted in 21 per cent of sick students. heat-labile enterotoxin-producing escheria coli was found in the stools of 72 per cent of sick and 15 per cent of healthy students. none had heat-labile esch. coli when they entered mexico. the in ... | 1975 | 163964 |
| effect of a low-molecular-weight dna binding protein, h1 factor, on the in vitro transcription of the lactose operon in escherichia coli. | h1 protein, a heat-stable low-molecular-weight dna-binding factor previously described by cukier-kahn et al. [proc. nat. acad. sci usa (1972) 69, 3643-3647] markedly stimulates in vitro synthesis of lac-specific rna directed by bacteriophage lambdah80 dlac or phi80 dlac dna templates in the presence of purified e. coli rna polymerase holoenzyme. the extent of stimulation obtained by addition of h1 alone is usually greater than that observed with the camp receptor protein-camp combination. h1 eff ... | 1975 | 164021 |
| cobalt(iii), a probe of metal binding sites of escherichia coli alkaline phosphatase. | to facilitate the study of individual metal binding sites of polymeric metalloproteins, conversion of exchange-labile co(ii) in e. coli alkaline phosphatase (ec 3.1.3.1) to exchange-inert co(iii) was examined. oxidation of co(ii) alkaline phosphatase with hydrogen peroxide results in a single absorption maximum at 530 nm and loss both of the characteristic electron paramagnetic signal and of enzymatic activity. zinc neither reactivates this enzyme nor displaces the oxidized cobalt atoms. metal a ... | 1975 | 164026 |
| effect of infectious bursal disease on the response of chickens to s typhimurium and e coli infections. | | 1975 | 164080 |
| priming of superhelical sv40 dna by escherichia coli rna polymerase for in vitro dna synthesis. | when closed circular sv40 dna containing 58 negative superhelical turns is used as a template for rna synthesis with escherichia coli rna polymerase, a fraction of the rna product remains complexed with the dna. the rna in the complex is resistant to ribonuclease in high salt, and the tm indicates that it is hydrogen bonded to the dna. the mole ratio of rna to dna nucleotides in the complex ranges from 0.01 to 0.08; the rna ranges in length from 80 to 600 nucleotides. the formation of the comple ... | 1975 | 164202 |
| interaction of 4,5-dibromo-2,7-di-(acetatomercuri)-fluorescein with dnas of different base composition. | the changes in absorption spectra in the visible region observed on adding different naturally occurring and synthetic dna duplexes to solutions of 4,5-dibromo-2,7-di-(acetatomercuri)-fluorescein indicate that the mercurial reacts with polynucleotides of this type. the reaction is reversible as proved by adding excess of kcn which restores the original spectra of the free dye. the interaction is characterised also by quenching of the fluorescence of the dye and the induction of optical activity ... | 1975 | 164231 |
| the purification and properties of superoxide dismutase from a blue-green alga. | soluble extracts of plectonema boryanum have been shown to contain a single, electrophoretically distinct, superoxide dismutase. the enzyme has been isolated and has been found to be an iron-containing enzyme similar to that described from the periplasm of escherichia coli. it contains 1 fe3+/mole of enzyme. the molecular weight was approximately 36 500, and the enzyme appeared to be composed of two subunits of equal size joined by non-covalent interactions. esr data are presented, as are the r ... | 1975 | 164232 |
| the interaction of estradiol-receptor protein with the genome: an argument for the existence of undetected specific sites. | in extracts from rat and calf uterus, the steroid hormone 17 beta-estradiol stimulates the binding of its specific receptor protein to dna. this interaction appears to be of low affinity (half of the estradiol-activated, 5s receptor bound at 300-400 mug/ml dna) and nonspecific with respect to dna base sequence. no binding to double-stranded rna is observed. these findings are consistent with several in vivo observations. in particular, when the cytoplasmic receptor protein binds hormone, it migr ... | 1975 | 164290 |
| lanthanum inhibition of vibrio cholerae and escherichia coli enterotoxin-induced enterosorption and its effects on intestinal mucosa cyclic adenosine 3',5'-monophosphate and cyclic guanosine 3',5'-monophosphate levels. | several trivalent cations, including lanthanum (la3+), inhibited the secretion (enterosorption) induced by the enterotoxins of vibrio cholerae and escherichia coli in the rabbit ileum in vivo. high concentrations (greater than 10 mm) of la3+ were required to inhibit cholera enterotoxin (ce)-induced enterosorption, probably because of the adsorption of the la3+ often potentiated the ce-induced enterosorption. if luminal la3+ exposure followed ce exposure, some recovery of the enterosorptive respo ... | 1975 | 164410 |
| intergration of the receptor for bacteriophage lambda in the outer membrane of escherichia coli: coupling with cell division. | induction of the synthesis of the receptor for phage lambda is obtained by adding maltose and adenosine 3'-5'-cyclic monophosphate to glucose grown cells of escherichia coli. bacteria induced for a short period of time were infected with a high multiplicity of phage lambda , and examined under the electron microscope. only a fraction of the bacteria were seen to have adsorbed a large number of phage particles. the majority of such bacteria had a constriction indicating formation of a septum, and ... | 1975 | 164434 |
| deletion of the escherichia coli crp gene. | spontaneous crp mutants escherichia coli were selected from a strain that does not require 3',5'-cyclic adenosine monophosphate for cap activity. several deletions of the crp gene were characterized. the crp gene was not essential for growth of e. coli. crp mutations reduced the donor ability of hfr strains. | 1975 | 164435 |
| the ultraviolet endonuclease of bacteriophage t4. further characterization. | the t4 ultraviolet endonuclease was previously shown to produce strand incisions (nicks) in ultraviolet-irradiated dna on the 5' side of thymine dimers. the present studies demonstrate that the purified endonuclease creates 3'-oh and 5'-p termini at the sites of nicking. photoreactivation of ultraviolet-sensitive sites, thereby demonstrating directly endonucleause has a molecular weight of approximately 18,000 and attacks ultraviolet-irradiated single-stranded escherichia coli and m-13 dna. | 1975 | 164454 |
| guanosine monophosphate synthetase from escherichia coli b-96. inhibition by nucleosides. | the mechanism of inhibition of gmp synthetase by purine and purine-analog nucleosides was investigated. it was found that in addition to allowing the nucleoside to bind to the enzyme (udaka, s., and moyed, h. s. (1963) j. biol. chem. 238, 2797)ppi was also a competitive inhibitor with respect to atp. a rate equation was derived to describe this inhibitory model for two competitive inhibitors where the binding of one inhibitor is contingent upon the binding of the other. the inhibition constants ... | 1975 | 164459 |
| the nucleotide sequences of the two glutamine transfer ribonucleic acids from escherichia coli. | the nucleotide sequences of the two glutamine trna species in escherichia coli k12 have been determined. sufficient data was obtained to order unambiguously the products of complete rnase digestion of trna2gln, and all but one oligonucleotide from trna1gln. the sequence of trna1gln was established by analogy with trna1gln, as the two trnas are very similar, differing by only 7 residues out of 75. trna1gln has the anticodon nug, where n is a modified nucleotide which is likely to be a derivative ... | 1975 | 164464 |
| comparative analysis of deletion and base-change mutabilities of escherichia coli b strains differing in dna repair capacity (wild-type, uvra-, pola-, reca-) by various mutagens. | dose-response curves were compared for deletions [colbr (resistant to colicin b) mutations being more than 80% deletions] and base changes (reversion of argfam to prototrophy argplus) induced in the same set of e. coli strains (wild-type for dna repair, uvra-, pola- and reca-) by n-methyl-n'-nitro-n-nitrosoguanidine (ntg), ethyl methanesulfonate (ems), hydroxylamine (ha), 4-nitroquinoline i-oxide (4nqo), mitomycin c (mtc, uv and x-rays. all these agents induced deletions as well as base changes ... | 1975 | 164624 |
| partial reconstitution of active ribosomes and 50s subunits. | escherichia coli ribosomes and their 50s subunits disassembled by licl treatment can be reconstituted into structurally completed but inactive particles. however, peptidyltransferase and polyphenylalanine synthesizing activity can be partly recovered by the addition of methanol to the reconstitution system. furthermore, entirely active ribosomes and 50s subunits are reconstituted when methanol is present during the initial treatment with licl to disassemble the ribosomal components. the presence ... | 1975 | 164889 |
| the role of superoxide radical in the autoxidation of cytochrome c. | the net rate of autoxidation of ferrocytochrome c was decreased by ferricytochrome c. superoxide dismutase accelerated this autoxidation to a limit and overcame the inhibitory effect of ferricytochrome c. this was the case whether the autoxidationwas observed in the presence or in the absence of denaturants, such as alcohols orurea, and whether the superoxide dismutase used was the cu-2+-zn-2+ enzyme from bovine erythrocytes or the mn-3+-enzyme from escherichia coli. it can be deduced that the a ... | 1975 | 164898 |
| cyclic adenosine monophosphate receptor: effect of cyclic amp analogues on dna binding and proteolytic inactivation. | the cyclic amp receptor protein of escherichia coli in the presence of cyclic amp undergoes a conformational change resulting in an increased affinity for dna and an increased susceptibility to attack by proteolytic enzymes resulting in loss of dna binding capacity. of several cyclic nucleotides tested only cyclic amp and cyclic tubercidin monophosphate are able to effect the conformational transition in cyclic amp receptor protein, prerequisite to proteolytic inactivation or dna binding. other ... | 1975 | 164914 |
| on the regulation of adenosine 3', 5'-monophosphate synthesis in bacteria. i. effect of carbon source variation on cyclic amp synthesis in escherichia coli b/r. | 1. the effect of carbon source variation in bacterial growth media on their growth rate, inducible enzyme and cyclic amp synthesis was examined: an inverse relationship between the culture's growth rate and its differential rate of inducible enzyme (tryptophanase and beta-galactosidase), and cyclic amp synthesis was found. 2. the effect of the culture's growth phase on its sensitivity or resistance to glucose catabolite repression was determined in the wild type and a catabolite insensitive muta ... | 1975 | 164929 |
| on the regulation of cyclic amp level in bacteria. ii. in vitro regulation of adenylate cyclase activity. solubilization and reconstitution of a functional membrane-bound adenylate cyclase system responsive to regulation by glucose. | 1. the in vitro regulation of the membrane bound adenylate cyclase of escherichia coli b/r by a variety of carbohydrates and one mammalian hormone was examined. 2. the membrane bound adenylate cyclase was found responsive to regulation by the various growth substrates and to glucagon. 3. solubilization of the bacterial membrane preparation by a procedure specific for the solubilization of the phosphotransferase enzyme e1 1 to its e1 1 a and e1 1 b subunits was found to be accompanied by the loss ... | 1975 | 164930 |
| regulation of galactose operon at the gal operator-promoter region in escherichia coli k-12. | the capr (lon) product controls expression of the gal operon independently of the galr repressor. previously, mutations of the gal operon have been isolated that are semiconstitutive and alter response to the capr and/or capt product. such mutants imply the existence of a distinct site in the operon that responds to capr (capt) control. this mutation could be either in a site near the operator-distal end of the gale gene, which signals rho factor termination of transcription in vitro or in a sit ... | 1975 | 165171 |
| two types of glucose effects on beta-galactosidase synthesis in a membrane fraction of escherichia coli: correlation with repression observed in intact cells. | a membrane fraction obtained from an osmotic lysate of escherichia coli spheroplasts retains capability to synthesize beta-galactosidase. the system also retains cellular regulatory functions, one of which is known as catabolite repression. two types of repression of beta-galactosidase synthesis were observed in this membrane system: one was caused by the addition of 2-deoxyglucose or glucose at a low concentration (3 times 10- minus 4 m), and the other was caused by glucose-6-phosphate or gluco ... | 1975 | 165172 |
| effect of glucose and its analogues on the accumulation and release of cyclic adenosine 3',5'-monophosphate in a membrane fraction of escherichia coli: relation to beta-galactosidase synthesis. | correlation between beta-galactosidase synthesis and cyclic adenosine 3',5'-monophosphate (camp) levels in a membrane fraction obtained from disrupted spheroplasts of escherichia coli was investigated. repression of beta-galactosidase synthesis in the membrane fraction by glucose-6-phosphate and by 2-deoxyglucose differed in sensitivity to reversal by camp. the difference between the two repressions could be due to the fact that glucose-6-phosphate inhibited severely the accumulation of exogenou ... | 1975 | 165173 |
| mechanism of the ribosome-dependent uncoupled gtpase reaction catalyzed by polypeptide chain elongation factor g. | at low nh4-+ concentrations, 50s ribosomal subunits from e. coli were fully active in the absence of 30s ribosomal subunits, in forming a complex with the polypeptide chain elongation factor g (ef-g) and guanine nucleotide (ternary complex formation), and also in supporting ef-g dependent hydrolysis of gtp (uncoupled gtpase reaction). however, both activities were markedly inhibited on increasing the concentration of the monovalent cation, and at 160 mm nh4-+, the optimal concentration for poly ... | 1975 | 165176 |