| proton-dependent binding of proline to carrier in escherichia coli membrane. | | 1977 | 18369 |
| enzymatic reduction of mercurous ions in escherichia coli bearing r factor. | mercurous ion (hg(+))-dependent reduced nicotinamide adenine dinucleotide phosphate oxidation was demonstrated in an extract from cells of escherichia coli w2252 that bear r factor. | 1977 | 18441 |
| characterization of the glutamine site of escherichia coli guanosine 5'-monophosphate synthetase. | alkylation of guanosine 5'-monophosphate (gmp) synthetase with the glutamine analogs l-2-amino-4-oxo-5-chloropentanoic acid (chloroketon) and 6-diazo-5-oxonorleucine (don) inactivated glutamine- and nh3-dependent gmp synthetase. inactivation exhibited second order kinetics. complete inactivation was accompanied by covalent attachment of 0.4 to 0.5 equivalent of chloroketon/subunit. alkylation of gmp synthetase with iodacetamide selectively inactivated glutamine-dependent activity. the nh3-depend ... | 1977 | 18463 |
| studies on the depolarization of the escherichia coli cell membrane by colicin e1. | | 1977 | 18466 |
| kinetic mechanism of trna nucleotidyltransferase from escherichia coli. | a kinetic analysis of the incorporation of amp into trna lacking the 3'-terminal residue by trna nucleotidyltransferase (ec 2.2.7.25) from escherichia coli is presented. initial velocity studies demonstrate that the mechanism is sequential and that high concentrations of trna give rise to substrate inhibition which is noncompetitive with respect to atp. in addition, the substrate inhibition is more pronounced in the presence of pyrophosphate, which suggests the formation of an inhibitory enzyme- ... | 1977 | 18468 |
| partial purification of 6-(d-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydropterin triphosphate synthetase from chicken liver. | an enzyme that catalyzes the formation of 6-(d-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydropterin triphosphate (d-erythrodihydroneopterin triphosphate) and formic acid from gtp has been purified about 3700-fold from homogenates of chicken liver. the molecular weight of the enzyme, d-erythrodihydroneopterin triphosphate synthetase (gtp cyclohydrolase), has been estimated to be 125,000 by gel filtration on ultrogel aca-34. the enzyme functions optimally between ph 8.0 and 9.2 and is considerably ... | 1977 | 18471 |
| inducible membrane-bound l-lactate dehydrogenase from escherichia coli. purification and properties. | | 1977 | 18473 |
| relationship between oxygen-induced proton efflux and membrane energization in cells of escherichia coli. | | 1977 | 18476 |
| differential susceptibility of escherichia coli and proteus mirabilis to mouse urine and to urea. | the purpose of this investigation was to compare the antimicrobial properties of mouse urine and of urea against escherichia coli and proteus mirabilis. nornal urine was found to inhibit the growth of e. coli and p. mirabilis, whereas urine from diuresing animals permitted multiplication of these bacteria. addition of urea to urine from diuresing animals restored its bactericidal effect on p. mirabilis but not on e. coli. this bactericidal effect on p. mirabilis was dependent on the additive act ... | 1977 | 18546 |
| experimental e. coli arthritis in the rabbit. a model of infectious and post-infectious inflammatory synovitis. | rabbit knee joints challenged with e. coli 06 underwent a self-limited infection lasting several weeks followed by a prolonged post-infectious inflammatory arthritis. the e. coli used did not possess collagenolytic activity nor did a variety of common aerobic clinical isolates. articular cartilage destruction occurred by two basically different mechanisms: u) direct invasion of pannus at the juxtaarticular margins, and 2) fibrillation in cartilage to cartilage contact areas. weekly measurement o ... | 1977 | 18606 |
| contamination of rat urine with gut flora using all-glass metabolism cages for collection of urine and faeces. | in rat urine collected in all-glass metabolism cages, at least four strains of intestinal microflora were found: two types of e. coli, enterobacter cloaceae and proteus vulgaris. the number of bacteria of each strain increased with time. 2. the ph of the urine increased from 6-9 after 24 h to 8-95 after 120 h. the ph of the urine of neomycin-treated rats remained nearly constant over a period of two days. 3. nitroreductase activity was present in the rat urine. added p-nitrobenzoic acid was redu ... | 1977 | 18846 |
| adrenergic mechanisms in infection. iii. alpha-and beta-receptor blocking agents in treatment. | raised epinephrine concentrations concentrations developed in the blood of mice near death after an intraperitoneal challenge with 10(9) staphylococcus aureus or escherichia coli. both epinephrine levels were elevated in the urine near death. these challenges were infections and not intoxications, as they could be successfully treated with antibiotics. using the same model infections, we studied the effect of alpha-and beta-receptor blocking agents and other adrenergically active compounds. the ... | 1977 | 18930 |
| glucose utilization and role of blood in endotoxin shock. | the present study was conducted to explore influences modifying glucose uptake in canine blood administered ld100 e. coli endotoxin. particular emphasis was given to assay the role of the white blood cell (wbc) in glucose utilization. significant increases in glucose uptake and lactic acid production, attributed to increased activity of the wbc, were observed 1-3 h after endotoxin was added to blood in vitro. although a net increase in glucose utilization was noted, endotoxin simultaneously exer ... | 1977 | 18939 |
| substrate kinetic isotope effects in dehydrogenase coupled active transport in membrane vesicles of escherichia coli. | | 1977 | 19035 |
| preparation and properties of a new dnase from aspergillus oryzae. | a dnase present in commercial preparations of aspergillus oryzae alpha-amylase was purified 1550-fold in 25% yield by acetone precipitation and by chromatography on diethylaminoethyl- and carboxymethylcellulose. the enzyme was isolated free of contaminating rnases and dnases. the molecular weight of the enzyme determined by gel filtration on sephadex g-100 was 48 000, while a molecular weight of 58 000 was determined for the single band observed upon polyacrylamide gel electrophoresis in sodium ... | 1977 | 19042 |
| escherichia coli dihydrofolate reductase: isolation and characterization of two isozymes. | a combination of affinity column chromatography and preparative gel electrophoresis has been used to purify to homogeneity the two isozymes of dihydrofolate reductase from a trimethoprim-resistant strain of escherichia coli b (rt 500). these enzyme forms are noninterconvertible and are present in crude cell lysates, but other electrophoretic species can be generated durng purification if sulfhydryl-protecting agents, such as dithiothreitol, are not present. the two isozymes, numbered form 1 and ... | 1977 | 19054 |
| partial purification and characterization of an n2-guanine rna methyltransferase from chicken embryos. | an n2-guanine rna methyltransferase has been purified 1000-fold from chick embryo homogenates by phosphocellulose chromatography followed by chromatography on s-adenosylhomocystein-sepharose. the enzyme was shown to methylate the g10 position of escherichia coli b trnaphe and has a km of 3x10(-7) m for trnaphe and 1.38 x 10(-6) m for s-adenosylmethionine. the molecular weight was estimated to be 77 000 by gel filtration and the ph optimum was 8.0 to 8.5. magnesium ion was not required for activi ... | 1977 | 19056 |
| stopped flow fluorescence studies on the binding of reduced nicotinamide adenine dinucleotide to citrate synthase of escherichia coli: effects of ph. | | 1977 | 19140 |
| the ability of enteric bacteria to catalyze the covalent binding of bile acids and cholesterol to dna and their in ability to metabolize benzo(a)pyrene to a binding product and to known metabolites. | the capacity of enteric bacteria (e. coli, salmonella, pseudomonas, shigella and klebsiella) to catalyze the covalent binding of benzo(a)pyrene (bp), cholic acid, deoxycholic acid and cholesterol was investigated. in general, these bacteria were incapable of activating bp to a covalently bound product with calf thymus dna. metabolism studies of bp by fluorometric assay failed to indicate any accumulation of bp-3-hydroxy in the incubation medium. detailed metabolic investigation with high-pressur ... | 1977 | 19150 |
| interaction of extrinsic fluorescent probes with e. coli glutamine synthetase. | binding of 2-p-toluidinylnaphthalene-6-sulfonate (tns) to adenylylated (e--11) glutamine synthetase is cooperative and time-dependent, with 3 dye sites per subunit. in fluorescence polarization experiments tns and pyrene butyrate give normalized perrin plots that indicate a symmetrical arrangement of dye excited state dipoles, relative to the rotational axis of the oblate ellipsoid of the dodecameric native enzyme. | 1977 | 19281 |
| solubilization of escherichia coli membrane proteins by aprotic solvents. | | 1977 | 19301 |
| the electrochemical proton gradient in escherichia coli membrane vesicles and its relationship to active transport. | | 1977 | 19318 |
| the multiplicity of components, energization mechanisms and functions involved in galactose transport into escherichia coli. | | 1977 | 19320 |
| characterization of salmonella typhimurium mutants with altered glutamine synthetase activity. | a number of glutamine auxotrophs of salmonella typhimurium were isolated and characterized genetically. three of the mutations appear to be closely linked and are complemented by episomes carrying the glna region of escherichia coli. the lesions in these strains are approximately 20% linked by p1 transduction with a mutation in the rha gene, but are unlinked to ilv. another mutation causing glutamine auxotrophy in strain jb674 is genetically distinct from the others. strain jb674 grown in glucos ... | 1977 | 19344 |
| effect of temperature on bacterial killing by serum and by polymorphonuclear leukocytes. | bacterial killing by serum alone and by polymorphonuclear )pmn) leukocytes was studied at 37 degrees c and compared with killing at 39 and 41 degrees c. the test organisms for serum killing were staphylococcus aureus 502a (serum resistant) and escherichia coli o14 (serum sensitive). the organisms used in pmn killing tests were streptococcus pneumoniae type 29 and e. coli o86.s aureus was not killed by serum alone at any temperature. changes in temperature did not affect the rate of serum killing ... | 1977 | 19356 |
| metabolism of 6-aminonicotinic acid in escherichia coli. | a late-log-phase culture of an escherichia coli nadb pnca double mutant took up 6-7-14caminonicotinic acid and excreted 6-14caminonicotinamide. this mutant also accumulated intracellularly several radioactive compounds which have been tentatively identified as 6-amino analogs of compounds in the pyridine nucleotide cycle. it is concluded that 6-aminonicotinamide and 6-aminonicotinic acid probably exert at least a portion of their bacteriostatic effects by being metabolized, by the enzymes of the ... | 1977 | 19420 |
| cyclic adenosine 3',5'-monophosphate regulation of membrane energetics in escherichia coli. | mutants of escherichia coli k-12 lacking functional adenylate cyclase (cya) or the cyclic adenosine 3',5'-monophosphate (camp) receptor protein (crp) were compared with their wild type to evaluate the role played by the camp-camp receptor protein complex in regulating this organism's membrane-associated bioenergetic functions. both mutants were found to be equally defective in carrying out various electron transport activities. in particular, their capacity for synthesizing a functional oxygen-l ... | 1977 | 19422 |
| dihydrodipicolinate reductases from bacillus cereus and bacillus megaterium. | dyhydrodipicolinate reductases were purified 100-fold from crude extracts of b. cereus and b. megaterium and their properties were compared with those of the reductase from b. subtilis. the molecular weights of the reductases of b. cereus and b. megaterium were fount to be 155,000 and 150,000, respectively. these reductases were shown to be free of flavin, unlike the b. subtilis enzyme, which contains flavin. both nadph and nadh acted as coenzymes for these two reductases. nadph being three or f ... | 1977 | 19431 |
| purification and properties of a t4 bacteriophage factor that modifies valyl-trna synthetase of escherichia coli. | after t4 bacteriophage infects escherichia coli, a peptide tau, produced under the control of a phage gene, binds to the host valyl transfer ribonucleic acid synthetase (ec 6.1.1.9) and thereby changes several of its physicochemical properties. the interaction of tau with the host enzyme was investigated in vitro after extensively purifying the factor from t4-infected e. coli using a rapid purification procedure. the tau preparation migrated as a single, protein-staining band with a molecular we ... | 1977 | 19475 |
| cross-protective immunity to gram-negative bacilli: studies with core glycolipid of salmonella minnesota and antigens of streptococcus pneumoniae. | two immunoprophylactic approaches to the control of infections caused by gramnegative bacilli were evaluated by study of experimental infections in animals. the core glycolipid antigen derived from the re mutant of salmonella minnesota r595 is shared by virtually all enteric bacteria, and immunization with this endotoxin protects against the hemodynamic sequelae of bacterial infection and pyrexia without enhancing intravascular clearance of bacteria. the degree of protection afforded by active a ... | 1977 | 19538 |
| the fira gene, a locus involved in the expression of rifampicin resistance in escherichia coli. ii. characterisation of bacterial proteins coded by lambdafira transducing phages. | the fira gene probably codes for an essential component of the transcription machinery in e. coli. bacterial proteins coded by lambdafira transducing phages have been examined after infection of a uv-irradiated lambda lysogen, and 2 major fir-specific proteins have been characterized. the larger protein has a molecular weight of 27,000 daltons. the smaller protein, of 17,000 daltons, is produced in a considerable molar excess over the larger protein, is basic and binds strongly to dna-, to deae- ... | 1977 | 19693 |
| shear degradation of dna. | a concentric-cylinder flow-birefringence instrument is used to generate sufficient shear fields to break t2 dna (m = 1.2 x 10(8)) and e. coli dna (m = 2.5 x 10(9)) in dilute solution. breakage is monitored in situ by measuring the change in birefringence relaxation after the flow has been stopped. the breakage of t2 dna follows first-order kinetics. rate constants are obtained as functions of shear rate and viscosity (varied by adding glycerol). the data are fitted by a modified arrhenius equati ... | 1977 | 19729 |
| superiority of interconvertible enzyme cascades in metabolite regulation: analysis of multicyclic systems. | escherichia coli glutamine synthetase and glycogen phosphorylase are prototypes for models of "closed" and "opened" bicyclic cascade systems. steady-state functions relating the fractional activation of interconvertible enzymes to the concentrations of allosteric effectors and to the catalytic constants of the several converter enzymes in such cascades were determined. the study shows that when the active form of an interconvertible enzyme in one cycle catalyzes the covalent modification of the ... | 1977 | 19739 |
| a relation between amino acid hydrophobicity and rate of uptake in escherichia coli. | | 1977 | 20084 |
| ph-dependent changes in proton:substrate stoichiometries during active transport in escherichia coli membrane vesicles. | experiments are presented in which the proton electrochemical gradient (deltamuh+) in escherichia coli membrane vesicles (interior negative and alkaline) was measured under a variety of conditions and compared with steady-state levels of accumulation of lactose, proline, d-lactate, and glucose-6-p measured under identical conditions. accumulation of lactose and proline is proportional to the magnitude of deltamuh+ at ph 5.5, where the ph gradient (deltaph) and the electrical potential (deltapsi) ... | 1977 | 20136 |
| the importance of lactobacilli in maintaining normal microbial balance in the crop. | 1. the effect of lactobacilli on escherichia coli has been examined in vitro and in chicken crop in vivo. 2. inhibition of e. coli was dependent on the presence of sufficient numbers of lactobacilli. 3. in a standard test some lactobacilli were bacteriostatic and one was bactericidal. the bacteriostasis was due to the low ph produced by these strains but bactericidal activity could not be accounted for by ph alone. 4. in gnotobiotic animals the bactericidal strain was no more inhibitory for e. c ... | 1977 | 20197 |
| repression of heat-stable enterotoxin synthesis in enterotoxigenic escherichia coli. | five different carbon sources were examined for their ability to control synthesis of heat-stable enterotoxin (st) by enterotoxigenic (ent+) escherichia coli grown in either a defined medium containing four amino acids or a minimal salts medium. no st activity was observed when d-glucose, d-gluconate, and l-arabinose were added separately to the defined medium, whereas glycerol and pyruvate decreased toxin levels. similar results were obtained using a minimal salts medium, except with pyruvate, ... | 1977 | 20404 |
| enzymatic synthesis of q nucleoside containing mannose in the anticodon of trna: isolation of a novel mannosyltransferase from a cell-free extract of rat liver. | the q nucleosides isolated from rabbit liver trna are known to have sugars (mannose or galactose) linked to their cyclopentene diol moiety. a q nucleoside containing mannose (manq) was synthesized by a cell-free system from rat liver, using purified e. coli trnaasp as an acceptor and gdp-mannose as a donor molecule. the novel mannosyltransferase catalyzing this reaction was purified from a particulate-free soluble enzyme fraction and found to be strictly specific for trnaasp. these results, toge ... | 1977 | 20603 |
| sodium-stimulated glutamate uptake in membrane vesicles of escherichia coli: the role of ion gradients. | membrane vesicles prepared from escherichia coli b/r grown on glutamate as a sole source of carbon and energy require sodium for glutamate accumulation when energized by d-lactate oxidation. glutamate uptake can also be driven by a prearranged sodium gradient (out to in) in the absence of an energy source or a protonmotive force. sodium ions are exchanged rapidly in respiring vesicles and the sodium gradient may be large enough under certain conditions to drive glutamate uptake after the protonm ... | 1977 | 20621 |
| fatty acid synthetase from brevibacterium ammoniagenes: formation of monounsaturated fatty acids by a multienzyme complex. | a multienzyme fatty acid synthetase complex isolated from brevibacterium ammoniagenes has been purified to a specific activity of 1440 nmol of malonyl-coa incorporated per min/mg. the enzyme is homogeneous, as judged by gel electrophoresis on agarose gels, and has a molecular weight of 1.2 x 10(6). both nadph and nadh are required for activity. in contrast to other fatty acid synthetase complexes, the enzyme catalyzes the synthesis of both long-chain saturated and monounsaturated fatty acids fro ... | 1977 | 20622 |
| direct evidence for separate binding sites for l-glu and amino acid feedback inhibitors on unadenylylated glutamine synthetase from e. coli. | | 1977 | 20883 |
| calorimetric and equilibrium binding studies of the interaction of substrates with glutamine synthetase of escherichia coli. | | 1977 | 20931 |
| direct measurement of association constants for the binding of escherichia coli lac repressor to non-operator dna. | | 1977 | 20938 |
| guanyl cyclase activity in the ef-t elongation factor of escherichia coli. | highly purified ef-ts from e. coli does contain guanylate cyclase activity, which is absent from other purified transfer factors, such as ef-tu and ef-g. guanylate cyclase activity has been characterized by its sensitivity to inhibitors and substrate specificity. although the physicochemical properties of guanylate cyclase are closely related to those of ef-ts, it does not appear to be a contaminant of this transfer factor, but a specific enzyme. the possible role of guanylate cyclase in protein ... | 1977 | 21022 |
| physical studies on the conformation of ribosomal protein s4 from escherichia coli. | proton magnetic resonance, circular dichroism and infrared spectroscopy were used to investigate the secondary and tertiary structure of the 16-s rna binding protein s4 from escherichia coli ribosomes. the proton magnetic resonance spectra of protein s4 in ribosomal reconstitution and low-salt buffers were identical and showed little dipolar broadening of the peaks, suggesting that the protein had an open extended structure. a ring-current-shifted apolar methyl resonance in the high-field region ... | 1977 | 21073 |
| generation of an electrochemical proton gradient by nitrate respiration in membrane vesicles from anaerobically grown escherichia coli. | | 1977 | 21080 |
| order-disorder conformation transition of hydrocarbon chains in lipopolysaccharide from escherichia coli. | | 1977 | 21082 |
| autogenous regulation of the synthesis of glutamine synthetase in klebsiella aerogenes. | we isolated an f' episome of escherichia coli carrying the glna+ gene from k. aerogenes and an f' episome of e. coli carrying the glna4 allele from k. aerogenes responsible for the constitutive synthesis of glutamine synthetase. complementation tests with these episomes showed that the glna4 mutation (leading to the constitutive synthesis of active glutamine synthetase) was in the gene identified by mutations glna20, glna51, and glna5 as the structural gene for glutamine synthetase. by using the ... | 1977 | 21158 |
| regulation of superoxide dismutase synthesis in escherichia coli: glucose effect. | growth of escherichia coli, based upon the fermentation of glucose, is associated with a low intracellular level of superoxide dismutase. exhaustion of glucose, or depression of the ph due to accumulation of organic acids, causes these organisms to then obtain energy from the oxidative degradation of other substances present in a rich medium. this shift in metabolism is associated with a marked increase in the rate of synthesis of superoxide dismutase. depression of the synthesis of superoxide d ... | 1977 | 21164 |
| studies of the beta-galactoside transporter in inverted membrane vesicles of escherichia coli. i. symmetrical facilitated diffusion and proton gradient-coupled transport. | facilitated diffusion of 14clactose into inverted membrane vesicles of escherichia coli was measured using hgcl2 as a stopping reagent and polylysine to flocculate the vesicles for filtration. equilibration of lactose between the internal and external volumes required expression of the y gene of the lac operon and was inhibited by thiodigalactoside or by prior incubation with n-ethylmaleimde or hgcl2. the initial rate of uptake was saturable, with a kt of 0.95 mm. counterflow of 14clactose was d ... | 1977 | 21183 |
| bromothymol blue and carbohydrate-sensitive plating media. | a new plating medium using bromothymol blue (btb) indicator is described and compared with eosin-methylene blue (emb), macconkey, and endo media. these media were tested with l-arabinose by plating fermenting and nonfermenting mutant strains of escherichia coli. the minimum concentrations of l-arabinose that permitted differentiation of these strains were determined. different concentrations were required for differentiating confluent patches of cells, isolated colonies, and closely spaced or ad ... | 1977 | 21196 |
| properties of deoxynucleoside 5'-monophosphatase induced by bacteriophage t5 after infection of escherichia coli. | bacteriophage t5 induced a deoxynucleoside 5'-monophosphatase during its infection of escherichia coli. the enzyme was purified about 100-fold. it was clearly distinct from the host 5'-nucleotidase activity in its physical characteristics and substrate specificity. the enzyme was active on deoxynucleoside 5'-monophosphates but was not active as a phosphatase on ribonucleotides, deoxynucleoside 5'-triphosphates, deoxynucleoside 3'-monophosphates, or deoxyoligonucleotides. furthermore, it did not ... | 1977 | 21305 |
| determinants of lung bacterial clearance in mice after acute hypoxia. | net lung bacterial clearance in normal mice is determined by the balance of in vivo bacterial multiplication on the one hand, and the defense mechanisms of mucociliary clearance and phagocytosis and killing by the oxygen-dependent alveolar macrophage on the other. the bactericidal function of the macrophage is the major component of the defense mechanism. the effect of acute hypoxia on the defense mechanism was studied in mice exposed to aerosols of staphylococcus aureus, escherichia coli, klebs ... | 1977 | 21603 |
| bacterial lipopolysaccharides as inducers of disease resistance in tobacco. | the cell wall component of pseudomonas solanacearum that induces disease resistance in tobacco was highly heat stable at neutral or alkaline ph but highly labile at acid ph. activity was unaffected by nucleases and proteases but destroyed by a mixture of beta-glycosidases. washing of bacterial cell walls released a lipopolysaccharide (lps) fraction with high inducer activity. purified lps, extracted by a variety of procedures from whole cells, isolated cell walls, and culture filtrates of both s ... | 1977 | 21613 |
| interaction of oligoribocytidylates with t7 dna in neutral and acid media. | oligoribocytidylates of chain length 4 to 12 were found to interact with native t7 dna at neutral and slightly acid ph. the results suggest that binding occurred at deoxycytosine clusters which may be displaced by the oligomers at neutral ph, while a local triple-stranded structure would be formed at acid ph. transcription of dna-(cp)n complexes by escherichia coli rna polymerase showed a decrease in level without affecting the specificity of the transcription, suggesting that oligocytidylate bi ... | 1977 | 21684 |
| counter-transport mediated by the lactose permease of escherichia coli. | when the two main energy yielding pathways, respiration and the membrane atpase of escherichia coli are poisoned, the lactose permease is unable to accomplish accumulative transport of thiogalactosides, but the efflux of preloaded substrate can be coupled to a transiently uphill transport of exogenous substrate. this transient uphill transport, called overshoot has been reexamined with the possibility of an obligate h+ cotransport in mind. overshoot can be diminished but not suppressed by a prot ... | 1977 | 21690 |
| effects of ph on the properties of normal and 5-fluorouracil-containing trnas. | transfer rnas isolated from escherichia coli b grown in the presence of 5-fluorouracil (fiura) show variations in their aminoacylation levels when compared with normal samples. some of these variations result from the more stringent aminoacylation reaction conditions required for fiura-trnas. increasing the reaction ph from 7 to 9 for example, generally causes a lowering of amino acid acceptance by the analog-containing trnas, while leaving control samples largely unchanged. this decreased activ ... | 1977 | 21694 |
| an ecf mutation in escherichia coli pleiotropically affecting energy coupling in active transport but not generation or maintenance of membrane potential. | | 1977 | 21876 |
| type i escherichia coli pili: characterization of binding to monkey kidney cells. | we have demonstrated binding of purified pili from a strain of escherichia coli to vero cell monolayers as a model of prokaryotic-eukaryotic cell adherence. pili bound to the tissue culture in a rapid reaction that did not require enzymatic activation. attachment occurred optimally at ph 4-5 and could be inhibited by analogues of d-mannose, anti-pili antibodies, or by preincubation of tissue cells with mannose-specific plant lectins. binding remained after treatment of the monolayer with glycosi ... | 1977 | 21933 |
| the enzymic interconversion of acetate and acetyl-coenzyme a in escherichia coli. | mutants of escherichia coli k12 have been isolated that grow on media containing pyruvate of proline as sole carbon sources despite the presence of 10 or 50 mm-sodium fluoroacetate. such mutants lack either acetate kinase atp: acetate phosphotransferase; ec 2.7.2.1 or phosphotransacetylase acetyl-coa: orthophosphate acetyltransferase; ec 2.3.1.8 activity. unlike wild-type e. coli, phosphotransacetylase mutants do not excrete acetate when growing aerobically or anaerobically on glucose; their ana ... | 1977 | 21941 |
| antibacterial effect, plasmid curing activity and chemical structure of some tricyclic compounds. | diethazine, amitriptyline and imipramine showed bacteriostatic and bactericidal effect on different bacteria. chlorpromazine sulphoxide and fluorescein were ineffective even at 1000 microgram/ml. the antibacterial compounds deleted at 40-70% frequency the f'lac plasmid of escherichia coli k12 le-140. | 1977 | 22219 |
| translation by bacterial cells of messenger rna for interferon of animal origin. | escherichia coli, strain ab 1157, cells are capable of translating human, mouse, and chicken messenter rna for interferon with production of interferon of the corresponding specifity. this translation occurs in the presence of serum. the activity of the resulting interferon decreased in parallel to dilution of the original mrna preparation, upon multiple ulitization of the mrna solution, as well as upon reduction of the interferon- producing activity of cells-donors of mrna due to prolonged stor ... | 1977 | 22228 |
| physico-chemical properties of interferon produced by a mixed leukocyte suspension. | physico-chemical properties of partially purified interferon produced by a mixed culture of human peripheral blood leukocytes following induction with double-stranded rna extracted from f2 phage infected escherichia coli were studied. molecular heterogeneity of the interferon preparation was demonstrated by gel chromatography on a sephadex g-100 column, disc electrophoresis in polyacrylamide gel and by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. the first two methods revealed 5 p ... | 1977 | 22229 |
| changes in the microflora and physiology of the anterior intestinal tract of pigs weaned at 2 days, with special reference to the pathogenesis of diarrhea. | the gastrointestinal microflora and gastric physiology of piglets weaned at 2 days was compared with that of piglets allowed to continue sucking the sow. although there was a significantly higher count of escherichia coli in the stomach, duodenum, and jejunum of the early-weaned compared with sow-reared pigs, these differences were not detectable in samples from the ileum. there were no quantitative differences in lactobacilli and in streptococci between the two treatments. lactobacillus ferment ... | 1977 | 22488 |
| adhesion of escherichia coli to human uroepithelial cells in vitro. | optimal conditions for in vitro adherence of escherichia coli to uroepithelial cells, previously shown to more efficient for strains causing acute symptomatic than that for strains causing "asymptomatic" urinary tract infections, were investigated. uroepithelial cells from fresh morning urine of healthy individuals and e. coli bacteria from patients with various forms of urinary tract infeciton were used. adhesion was found to vary, between individuals and epithelial cell types, with epithelial ... | 1977 | 22493 |
| gltb gene and regulation of nitrogen metabolism by glutamine synthetase in escherichia coli. | a mutant (gltb) of escherichia coli lacking glutamate synthase (gogat) was unable to utilize a wide variety of compounds as sole nitrogen source (e.g., arginine, proline, gamma-aminobutyrate, and glycine). among revertants of these asm- strains selected on one of these compounds (e.g., arginine, proline, or gamma-aminobutyrate) were those that produce glutamine synthetase (gs) constitutively (glnc phenotype). these revertants had a pleiotropically restored ability to grow on compounds that are m ... | 1978 | 22535 |
| ammonia assimilation and glutamate formation in caulobacter crescentus. | in the dimorphic bacterium caulobacter crescentus, ammonia assimilation occurs only via the combined action of the enzymes glutamine synthetase and glutamate synthase. mutants auxotrophic for glutamate lacked glutamate synthase activity, and the mutations leading to the glutamate auxotrophy appeared to lie at two distinct genetic loci. both glutamate synthase and glutamine synthetase activities were subject to regulation by repression. glutamate synthase activity was highest in cultures grown in ... | 1978 | 22537 |
| resistance to acridines and thymineless death in a mec- mutant of escherichia coli proceedings. | | 1977 | 22640 |
| catalysis of dna reassociation by the escherichia coli dna binding protein: a polyamine-dependent reaction. | | 1977 | 22760 |
| biochemical properties of a penicillinase from escherichia coli carrying rms 298. | we obtained two r plasmids, i.e., rms195 and rms298, from a clinical isolate, e. coli gn5503. penicillin beta-lactamase (pcase) was extracted from ml1410 rms195+ and rms298+, and was purified by chromatography. rms195 pcase was identical to the type i pcase mediated by r-tem, ri and rms212. the isoelectric point of rms298 pcase was 5.9 and its molecular weight was 21,000 +/- 1,000. the substrate profile and physiochemical properties indicate that rms298 pcase belongs to the type iv pcase mediate ... | 1977 | 22803 |
| secretion of various antimicrobial substances in dogs with experimental bacterial prostatitis. | bacterial prostatitis in dogs was induced by injection of an e. coli 06 suspension into a branch of the prostatic artery. three to six days later, secretion from the inflamed glands was obtained by pilocarpine stimulation and the concentrations of trimethoprim, sulphamethoxazole, erythromycin, doxycycline and ampicillin were measured during constant infusion of these drugs. in the prostatic secretion, only the concentrations of the lipid soluble substances trimethoprim and erythromycin exceeded ... | 1977 | 22949 |
| e. coli penicillin amidase. physico-chemical properties of the enzyme covalently bound to the 2-(3'-amino-4'-methoxyphenyl)-sulfonylethyl ester of cellulose. | the effect of the procedure of the enzyme binding with the carrier on the properties of the heterogenous catalyst obtained by covalent binding of penicillinamidase (pa) with cellulose 2-(3'-amino-4'-methoxyphenyl)-sulphonylethyl ether by means of the bifunctional reagent, i.e. glutaric aldehyde was studied. it was shown that the amount of the bound enzyme increased with a rise in the amount of the enzyme taken for the binding, while the binding efficiency characterizing the part of the active en ... | 1977 | 23067 |
| 2-deoxy-d-galactose, a substrate for the galactose-transport system of escherichia coli. | the following observations showed that 2-deoxy-d-galactose is a useful tool for the isolation and elucidation of the activity of one system for galactose uptake into escherichia coli. 1. 2-deoxygalactose, which is not a substrate for growth of e. coli, was transported into strains of the organism induced for galactose transport. 2. by using appropriate mutants it was shown that 2-deoxygalactose is a much better substrate for the galactose-transport system than for the methyl galactoside-transpor ... | 1977 | 23115 |
| evidence for an electrogenic 3-deoxy-2-oxo-d-gluconate--proton co-transport driven by the protonmotive force in escherichia coli k12. | evidence is presented indicating that the carrier-mediated uptake of 3-deoxy-2-oxo-d-gluconate and d-glucuronate in escherichia coli k12 is driven by the deltaph and deltapsi components of the protonmotive force. 1. approximately two protons enter the cells with each sugar molecule, independent of the sugar and the strain used. 2. in respiring cells, the magnitude of the ph gradient alone, as measured by distribution of 3hacetate, appears to be insufficient to account for the chemical gradient o ... | 1977 | 23116 |
| arginine decarboxylase from escherichia coli b: mechanism of dissociation from the decamer to the dimer. | the mechanism by which arginine decarboxylase dissociates from a decamer to a dimer has been examined by allowing a sulfhydryl group, available in the dimer but not the decamer, to react with 5,5'-dithiobis(2-nitrobenzoic acid). initial rates of dissociation were obtained by following the resulting increase in absorbance at 412 nm in a stopped-flow spectrophotometer. the rate of dissociation increases linearly with the protein concentration and reaches a maximum as a function of the concentratio ... | 1978 | 23144 |
| mechanisms and rate equations for dissociating systems. | the results presented in the previous paper (boeker, e.a. (1978), biochemistry 17 (preceding paper in this issue) indicate that the dissociation of the decamer of arginine decarboxylase of escherichia coli b is enhanced by na+ and retarded by h+. in this system, substances which increase the rate of dissociation can be treated kinetically either as substrates or activators, and substances which retard dissociation can be treated as products or inhibitors. in addition, the events needed for disso ... | 1978 | 23145 |
| ph dependence of the kinetic parameters of l-asparaginase. | the concentration dependence of the rate of hydrolysis of l-asparagine by escherichia coli l-asparaginase (l-asparagine amidohydrolase, ec 3.5.1.1) has been measured over the range ph 4.5 to ph 9.1 by a direct spectrophotometric assay at 220 nm and by a coupled assay utilizing glutamate dehydrogenase to detect the ammonia produced. the velocity of the hydrolysis reaction at saturating levels of substrate is independent of ph over this interval. the plot of v/km over the same interval is bell-sha ... | 1978 | 23162 |
| synthesis of acyl phosphatidylglycerol from phosphatidylglycerol in escherichia coli k-12. evidence for the participation of detergent-resistant phospholipase a and heat-labile membrane-bound factor(s). | the conversion of phosphatidylglycerol to acyl phosphatidylglycerol by extracts of escherichia coli k-12 strains was examined under various conditions. the maximum rate of conversion was observed at ph 7.2 in the presence of 50% (v/v) diethyl ether and 10 mm cacl2. this conversion was found to involve two sequential reactions: (1) the formation of 2-acyl glycerophosphoglycerol and 2-acyl glycerophosphoethanolamine from phosphatidylglycerol and phosphatidylethanolamine, respectively, by detergent ... | 1978 | 23168 |
| further studies on the cardiolipin phosphodiesterase of escherichia coli. | the cardiolipin phosphodiesterase of escherichia coli was further characterized. this enzyme has a ph optimum of 7.0 and is mg2+ dependent. mn2+ and co2+ could replace mg2+ but other divalent cations were inhibitory or without effect. the enzyme is not periplasmic and does not appear to be associated with membrane fractions prepared by different methods. it is recovered as a soluble protein in the cytosol fraction but could not be readily purified because of its instability. with cell-free syste ... | 1977 | 23209 |
| endotoxemia and large intestinal blood flow in subhuman primates. | the hemodynamic effects of escherichia coli endotoxin (ld80) were measured in the large intestine of anesthetized rhesus monkeys to determine whether this organ contributes to the pathogenesis of experimental shock. inferior mesenteric arterial blood flow (imf) was measured with an electromagnetic flowmeter. pressures within the aorta (ap) and portal vein (pp) were recorded. distribution of colon blood flow was measured with radioactive microspheres: ce, sr, and cr were injected into the left he ... | 1977 | 23223 |
| isolation and characterization of a phospholipase a2 from an inflammatory exudate. | sterile peritoneal exudates produced in rabbits injected with 1% glycogen contain a phospholipase a activity in a cell-free supernatant fraction that hydrolyzed a synthetic phospholipid (1,2-diacyl-sn-glycero-3-phospho-ethanolamine) and phospholipids of autoclaved escherichia coli. this phospholipase activity (phosphatidylacylhydrolase ec 3.1.1.4) exhibited an apparent bimodal ph optimum (ph 6.0 and ph 7.5) and was ca(2+)-dependent; mg(2+) and monovalent cations (na(+) and k(+)) did not substitu ... | 1978 | 23403 |
| the mode of action of n-(n-dodecyl)diethanolamine with particular reference to the effect of protonation on uptake by escherichia coli. | in a homologous series of n-(n-alkyl)diethanolamines antimicrobial activity was related to surface activity and increasing octanol-water partition coefficient. maximum activity was exhibited by the dodecyl-, tetradecyl- and hexadecyl-derivatives. dodecyldiethanolamine (dde) displayed a broad spectrum of activity. towards escherichia coli ncib8277, its bacteriostatic and bactericidal activity increased as the degree of protonation lessened, and may have been influenced by the formation of micelle ... | 1977 | 23410 |
| a ph-conditional mutant of escherichia coli. | mutants of escherichia coli have been isolated that are able to grow on lactose at ph 7.0 but not at ph 8.1. one of these mutants was analyzed and shown to map in the z region of the lactose operon. beta-galactosidase (beta-d-galactoside galactohydrolase; ec 3.2.1.23) activity in toluenized mutant cells at ph 8.0 was one-tenth that at ph 7.0. enzyme purified to near homogeneity from the ph-conditional mutant similarly exhibited ph-conditional activity under conditions where wild-type enzyme was ... | 1977 | 23535 |
| study of e. coli penicillin amidase. the ph-dependence of the enzymatic inactivation kinetics. | the ph-dependence of the inactivation rate constant of penicillin amidase at a temperature of 40 degrees c was studied. it was shown that in all cases the enzyme inactivation corresponded to the kinetics of the reaction of the 1st order. the ph-dependence profile was found to be bell-shaped, the effect of transfer from the highest to the lowest values of the inactivation rate constants increasing more than 100 times. on the basis of the data obtained and published earlier it was concluded that t ... | 1978 | 23720 |
| asymmetric distribution of nitrate reductase subunits in the cytoplasmic membrane of escherichia coli: evidence derived from surface labeling studies with transglutaminase. | | 1978 | 23727 |
| steady-state kinetic studies of the negative co-operativity and flip-flop mechanism for escherichia coli alkaline phosphatase. | 1. a study of variations in experimental error of velocity measurement with substrate concentration for alkaline phosphatase reveals that the standard error is not constant or strictly proportional to velocity, but obeys a more complex dependence. 2. by using an approach based on error estimates at each individual substrate concentration, we show that the double-reciprocal plots in general are curved, necessitating a high-degree rate equation. the curves are analysed according to a recent classi ... | 1977 | 23764 |
| sodium-proton antiport in isolated membrane vesicles of escherichia coli. | | 1978 | 23828 |
| regulation of gamma-aminobutyric acid degradation in escherichia coli by nitrogen metabolism enzymes. | the possible role of glutamate dehydrogenase, glutamate synthase, and glutamine synthetase in the regulation of enzyme formation in the gamma-aminobutyric acid (gaba) catabolic pathway of escherichia coli k-12 was investigated. evidence is presented indicating that glutamine synthetase acts as a positive regulator in the e. coli gaba control system. mutations impairing glutamate synthase activity prevent the depression of the enzymes of the gaba pathway in ammonia-limited glucose media. however, ... | 1978 | 24037 |
| regulation of biosynthesis of aminoacyl-trna synthetases and of trna in escherichia coli. i. isolation and characterization of a mutant with elevated levels of trnagln 1. | | 1977 | 24122 |
| orientation of the protonmotive force in membrane vesicles of escherichia coli. | | 1977 | 24138 |
| genetic analysis of the nitrogen fixation system in klebsiella pneumoniae. | fine structure mapping of nif mutations of klebsiella pneumoniae was accomplished by means of pl-transductional crosses and the plasmid r144 drd mediated conjugations. the physical distance between nif mutations based on the percentage of co-transduction with hisd of the nif mutations was estimated. the maximal distance between two mutations was calculated about 3 kb, and the average distance between different nif mutations was about 1 to 2 kb. so no "silent region" was shown within the nif clus ... | 1977 | 24272 |
| study of e. coli penicillin amidase. the ph dependence of the equilibrium constant of ampicillin enzymatic hydrolysis. | the equilibrium parameters of the hydrolysis of ampicillin catalysed by penicillin amidase were determined within the ph range of 4.5 to 5.5. the values of the ionization constants of the carboxy group of d-(-)-alpha-aminophenylacetic acid (pk1=1.80) and amino group of 6-aminopenicillanic acid (pk2=4.60) were estimated and ph-dependence of the effective free energy of ampicillin hydrolysis was calculated. it was shown that the thermodynamic optimum of ampicillin synthesis was at 3.20 (the value ... | 1978 | 24408 |
| stabilization of the relaxed state of aspartate transcarbamoylase by modification with a bifunctional reagent. | native aspartate transcarbamoylase from escherichia coli was modified with the bifunctional reagent tartaryl diazide in the presence of the substrate carbamoyl phosphate and the substrate analog succinate. the product had the same sedimentation coefficient as the native enzyme but showed a marked increase in affinity for the substrate aspartate with a hyperbolic saturation curve. the michaelis constant for aspartate (7.4 mm) is similar to that estimated for the relaxed state of the enzyme. the h ... | 1978 | 24638 |
| survival of plasmid-containing strains of escherichia coli, pseudomonas aeruginosa and staphylococcus aureus in phenylmercuric nitrate and thiomersal. | strains of escherichia coli, pseudomonas aeruginosa and staphylococcus aureus harbouring plasmids that confer mercury resistance grew in nutrient broth containing concentrations of phenylmercuric nitrate (pmn) that were inhibitory to isogenic plasmid-less strains. decimal reduction times of p. aeruginosa and s. aureus in aqueous pmn solution were also increased by the presence of plasmids. the viable count of a plasmid-containing p. aeruginosa strain in davis and mingioli's minimal medium (dm) c ... | 1978 | 24710 |
| endo r dpni restriction of escherichia coli dna synthesized in vitro. evidence that the ends of okazaki pieces are determined by template deoxynucleotide sequence. | | 1977 | 24749 |
| transformation of straight flagella and recovery of motility in a mutant escherichia coli. | | 1978 | 24751 |
| the role of fibrin formation in the pathogenesis of bacteremic shock in the primate. | in this study, an attempt was made to elucidate further the role of intravascular fibrin formation in the pathogenesis of sepsis in the primate. it was found that injected live escherichia coli caused death in primates within four to 11 hours as a result of microcirculatory failure and acidosis. pretreatment with arvin did not prolong the survival rate, probably because of an overloading of the reticuloendothelial system with fibrin degradation products. this study does not support an obligatory ... | 1978 | 24899 |
| purification and some properties of riboflavin synthetase from bacillus stearothermophilus atcc 8005. | a riboflavin synthetase was purified 51-fold from a thermophilic organism, bacillus stearothermophilus atcc 8005, that grew at 40 to 72 degrees c. some of the properties of the enzyme are: (i) its temperature optimum was 95 degrees c, and the activity was negligible below 40 degrees c; (ii) the arrhenius plot of the initial reaction rates was concave upward, with a break at 65 degrees c, and the apparent activation energies below and above 65 degrees c were 4.2 x 10(4) and 6.7 x 10(4) j/mol, res ... | 1978 | 25043 |
| simple bacterial preservation medium and its application to proficiency testing in water bacteriology. | a medium composed of nutrient broth, 1.8% boric acid, and 1% sodium chloride at ph 7.0 was shown to maintain the stability of escherichia coli cultures for up to 10 days at room temperature. by using this preservation medium for preparing a simulated sample a successful proficiency test survey in water bacteriology was conducted. | 1978 | 25046 |
| on the measurement of ph in escherichia coli by 31p nuclear magnetic resonance. | the 31p high resolution nmr spectra of concentrated suspensions of escherichia coli cells have been measured at 145.8 mhz. the position of the orthophosphate resonance is used as a measure of internal and external ph. in accord with paddan, zilberstein and rottenberg ((1976) eur. j. biochem. 63, 533--541) it is shown that when properly energized the internal ph is 7.5 +/- 0.1. by synchronizing the nmr data acquisition with 3-s bursts of o2 it is possible to measure the internal ph with a time re ... | 1978 | 25081 |