a contemporary review of incidence and detection of enterotoxigenic e. coli strains in human diarrheal diseases. | methodical possibilities for detection of enterotoxic strains of e. coli and the frequency of appearence of these strains in infants and adults suffering from diarrheal diseases are reviewed. our own study, using the ligated rabbit intestinal loop, revealed 6.8% incidence of enterotoxin producing strains among the classical enteropathogenic serotypes of e. coli, isolated from stools of infants with mild diarrhoea. the model of mice intestinal loop was not found to be suitable for detection of en ... | 1977 | 325951 |
"r"-living vaccine against colibacillosis. communication i. | after our estimation of the ld100 of enteropathogenic e. coli 0149 and 0138 (and their toxins) in rabbits and mice (intravenously and subcutaneously or intraperitoneally, respectively), rabbits and mice were vaccinated subcutaneously by the living "r" 0149 vaccine. all animals showed resistance against the ld100 of both e. coli serotypes; this state of resistance lasted 1-5 months in rabbits, and 1-3 months in mice. sera of vaccinated rabbits showed bactericidal activity against both e. coli ser ... | 1977 | 325952 |
[biological activity of extracts isolated from a virulent strain of sh. flexneri grown in the presence of calcium ions]. | the authors carried out a comparative study of the genetically connected sh. flexneri cultures (3 virulent strains, 3 clones of an avirulent mutant selected in the flux of an oblique light from the virulent strain, and lac+ kcp a-hybrids obtained by crossing the initial virulent cultures with the e. coli k12 hfr strains). the absence of any correlation between the virulence of the strains under study and the lipopolysaccharide (by rhamnose) content in the extracts from them in growing the cultur ... | 1977 | 325961 |
[morphologic mutant of escherichia coli k12 having disorders in morphology, division and cell wall biosynthesis]. | a study was made of the properties of a spherical mutant obtained from the e. coli k12 hfrc strain under the effect of n-nitroso-n-methyl-urea. the growth of the mutant of full value media was characterized by a marked reduction of the cell division at the rest phase, but exponential growth phase failed to differ from the growth of the parental strain. electron microscopic study of surface structures of the mutant cells which grew under physiological conditions permitted to distinguish two types ... | 1977 | 325965 |
[role of several physico-chemical surface properties of bacteria in the machanism of the initial phases of phagocytosis]. | an attempt was made on e. coli pattern to reveal the role played by the surface charge and the extent of the surface hydration in the mechanism of the initial phagocytosis phases (attraction and submersion). phagocytosis experiments with washed bacteria and washed rabbit leukocytes demonstrated a marked direct dependence of the electrophoretic velocities of escherichia and the intensity of their phagocytic ingestion, and a strong reverse relationship between the extent of hydration and the phago ... | 1977 | 325969 |
asymptomatic bacteriuria in schoolgirls. vi. the correlation between urinary and faecal escherichia coli. relation to the duration of the bacteriuria and the sampling technique. | the occurrence of the urinary strain in the anus, rectum and faeces was investigated in 27 girls with asymptomatic bacteriuria (abu). in patients with bacteriuria of relatively short duration 46% of the faecal isolates were of the urinary strain as compared to only 18% in patients with bacteriuria of relatively long duration. in general the correlation between the urinary and faecal flora is striking at the time of establishment of abu but diminishes with time. the diminished correlation may be ... | 1977 | 325992 |
epidemic diarrhea at crater lake from enterotoxigenic escherichia coli. a large waterborne outbreak. | in june and july 1975, gastrointestinal illness occurred in more than 200 staff members and 2000 visitors to an american national park. in was characterized by prolonged diarrhea, cramps, nausea, and vomiting, lasted a median duration of 8 days, and was significantly associated with consumption of park water (p less than 0.001), which had been contaminated by raw sewage. enterotoxigenic escherichia coli serotype 06:k15:h16 was isolated from 20 of 49 ill park residents and from the park's water s ... | 1977 | 326116 |
[study of a "rfa" locus coding for cell wall lipopolysaccharide core biosynthesis in "shigella flexneri" f6s (author's transl)]. | the rfa-7 lipopolysaccharide core mutation carried by the r mutant f680, derived from shigella flexneri f6s serotype 5b, has been mapped by conjugation and transduction experiments. the results show a chromosomal distance of about 1 min between rfa-7 and mtl. such a position would be similar to those of rfa genes in escherichia coli k12 and salmonella typhi-murium lt2. conjugational transfer of e. coli k12 rfa+ genes to mutant f680 restored s. flexneri o-specificity. chemical analyses performed ... | 1977 | 326120 |
the use of bile - esculin agar for the taxonomic classification of the family enterobacteriaceae. | bile-esculin medium has been used for many years for the presumptive identification of group d streptococcus. the test is based on the ability of a bacterium to grow in the presence of 40% bile and produce esculinase. 2935 strains of enterobacteriaceae were inoculated onto bile-esculin agar slants and incubated at 35 c. esculin hydrolysis was determined after 24 and 48 hours. at 24 hours of incubation esculin hydrolysis was limited to the genera klebsiella, enterobacter, serratia, and the specie ... | 1977 | 326178 |
genetics of colicin e susceptibility in citrobacter freundii. | the insensitivity of citrobacter freundii to the e colicins is based on tolerance to colicin e1 and resistance to colicins e2 and e3. spontaneous colicin a resistant mutants of c. freundii also lost their colicin e1 receptor function. sensitivity to colicin e1 can be induced by f'gal+tol+ plasmids, the tol a+ gene product of which is responsible for this effect. receptor function for colicins e2 and e3 is induced by the e. coli f'14 bfe+ plasmid, which is also able to enhance notably the recepto ... | 1977 | 326179 |
continuous-flow system for large-scale ultraviolet irradiation of bacterial cells. | a quartz-flow-cell system for irradiation of large volumes of escherichia coli cultures with ultraviolet light is described. with this system kilogram quantities of irradiated cells can be obtained for biochemical studies. changes in respiration and in specific activities of superoxide dismutase and catalase, after an ultraviolet treatment that reduced viability of culture samples to 0.2%, were in good agreement with those for cultures irradiated (52j/m2) by a conventional small-scale method to ... | 1977 | 326191 |
proline excretion in escherichia coli: a comparison of an argd+ strain and a proline-excreting argd- derivative. | in an attempt to deduce the physiological basis of proline excretion in argd- strains of escherichia coli k12, several properties of an argd+ (nonexcreting) and an argd- (excreting) derivative were compared. no difference was found in the transport or in the utilization of either proline or its immediate precursor, delta1-pyrroline-5-carboxylate (pca). furthermore, no differences were found in the physical or kinetic properties of partially purified preparations of the enzyme mediating the final ... | 1977 | 326254 |
the dissociation of sigma-factor from ribonucleic acid polymerase. | the sigma-factor of escherichia coli rna polymerase was shown to dissociate from the core enzyme as a function of absolute concentration. the association constant is in the range 10(6)-10(8) litre/mol. this implies that the amount of holoenzyme, core enzyme and sigma-factor in rna polymerase assays may vary according to the absolute concentration of the enzyme. | 1977 | 326256 |
enhancement of dna polymerase ii activity in e. coli after treatment with n-methyl-n'-nitro-n-nitrosoguanidine. | | 1977 | 326258 |
enteric flora of normal laboratory guinea-pigs. | the bowel flora of guinea-pigs was studied using non-selective cultural conditions and conditions highly selective for escherichia coli organisma. no e. coli were cultured from adult or juvenile bowel content. parallel studies showed that culture media supported the growth of small numbers of reference e. coli "seeded" into them along with bowel content. it is concluded that normal adult laboratory guinea-pigs may be bacteriologically equivalent to the ncs strain of "e. coli-free" mice. | 1977 | 326289 |
acute suppurative thyroiditis caused by escherichia coli. | | 1977 | 326342 |
improved procedure of selective enrichment of shigella in the presence of escherichia coli by use of 4-chloro-2-cyclopentylphenyl beta-d-galactopyranoside. | a previously described procedure for the selective enrichmen of shigella in competition with e. coli has been modified and tested with a total of 48 strains of the four shigella species. the new enrichment medium consists of 1,5-strength trypticase soy broth, 1 mm 4-chloro-2-cyclopentylphenyl beta-d-galactopyranoside (cppg), 0.25% lactose, and 0.1 m citrate buffer (ph 6.2). in competition with a 1000-fold higher population of e. coli than shigella, 42 of 48 strains from the four species of shige ... | 1977 | 326358 |
preferential inhibition of phosphatidyl ethanolamine synthesis in e. coli by alcohols. | growth of e. coli in the presence of alcohols of chain lengths 1 through 8 results in an increase in the relative abundance of phosphatidyl glycerol. this results primarily from the preferential inhibition of phosphatidyl ethanolamine synthesis. this inhibition appears to be unrelated to membrane fluidity or to changes in fatty acid composition caused by alcohols. alcohol-induced changes in total fatty acid composition are reflected in all phospholipid classes. phosphatidyl serine synthetase is ... | 1977 | 326363 |
acute undifferentiated neonatal diarrhea of beef calves: the prevalence of enterotoxigenic e. coli, reo-like (rota) virus and other enteropathogens in cow-calf herds. | | 1977 | 326373 |
[the effect of renal e. coli inoculation on the production of hypertonic urine in rats (author's transl)]. | | 1977 | 326406 |
anomalous synthesis of ppgpp in growing cells. | in e. coli cells, accumulation of ppgpp is normally triggered by conditions that restrict the aminoacylation of trna or interfere with carbon/energy source metabolism; in both cases, the nucleotide's accumulation is associated with control of stable rna synthesis and is generally believed to bring it about. we have found an anomalous situation wherein vigorously growing cells accumulate a high level of ppgpp and there is no restriction of stable rna synthesis. this occurs when wild-type cells ar ... | 1977 | 326415 |
partial inhibition of dna synthesis gives rise to increase in the level of inorganic pyrophosphatase in the growing cells of escherichia coli. | | 1977 | 326431 |
[repair kinetics of postreplication gaps in dna of uv-irradiated escherichia coli dnag mutant]. | | 1977 | 326506 |
granulocyte transfusions in recovery of neutropenic rats from induced e. coli toxicemia. | rats made transiently neutropenic by intra-arterial administration of vinblastine (3 mg/kg) and infected with e. coli (6.02+/-0.45 x 10(8), per animal) have a mortality rate of 90% within 48 h post infection. multiple transfusions of large numbers of granulocytes (harvested from deca-durabolin treated donor rats) protected the neutropenic animals from sepsis. out of a group of 11 rats, 10 recovered completely after repeated granulocyte transfusions. | 1977 | 326570 |
structure and function of escherichia coli ribosomes. | | 1977 | 326577 |
escherichia coli serotypes throughout the gastrointestinal tract of patients with intestinal disorders. | the o and h serotypes of escherichia coli that were present along the entire length of the gastrointestinal tract of patients with small intestinal bacterial overgrowth were studied. multiple sero- and biotypes were represented, although usually a single serotype predominated in each patient. in a number of cases the different o:h serotypes were antigenically related indicating that antigenic degradation was occurring. the serotypes isolated from the stomach and small intestine were represented ... | 1977 | 326634 |
susceptibility of lipopolysaccharide mutants to the bactericidal action of human neutrophil lysosomal fractions. | acetate extracts of purified human neutrophil granules (a mixed population containing specific and azurophil granules) were dialyzed against phosphate-buffered saline (ph 7.0) and tested for bactericidal activity against smooth parent and rough mutant, gram-negative bacteria. rough (re) mutants of escherichia coli, salmonella typhimurium, and salmonella minnesota were exquisitely more sensitive to extracts of human polymorphonuclear leukocyte granules than were their smooth (s) parents. the mean ... | 1977 | 326666 |
immunological responsiveness to escherichia coli during pregnancy. | to determine whether immunological responsiveness to a bacterial antigen is altered during pregnancy and lactation, swiss mice (gestation, 19 to 21 days) were studied during early, middle, and late pregnancy and in the early postpartum period. pregnant and nursing mice, each along with a virgin female littermate control, were injected with 2 x 10(6) heat-killed escherichia coli and sacrificed 4 days later for the enumeration of splenic anti-e. coli plaque-forming cells (pfc). for 72 4- to 10-day ... | 1977 | 326667 |
inhibitory action of galactose on phagocytes from normal and hypergalactosemic chicks. | the inhibitory effect of galactose on phagocyte function was investigated in normal and hypergalactosemic chicks by monitoring the in vitro killing of escherichia coli by leukocytes and the in vivo clearance of colloidal 125i-labeled bovine serum albumin ([125i]bsa) from the circulation. elevated levels of galactose (30 mm) significantly impaired the bactericidal activities of leukocytes from both control and hypergalactosemic chicks. however, the latter cells were more susceptible to the galact ... | 1977 | 326668 |
protective role of complement in experimental escherichia coli endocarditis. | fourteen strains of escherichia coli were tested for ability to cause infective endocarditis in rabbits prepared by prior placement of an intracardiac catheter. strains that were resistant to the bactericidal action of serum caused e. coli endocarditis in 91.4% of rabbits, whereas serum-sensitive strains usually failed to cause persisting infection (11.3% infected, p less than 0.001). although serum-sensitive e. coli lodged on heart valves within 1 h after intravenous injection, they survived le ... | 1977 | 326670 |
interactions of radio-detoxified escherichia coli endotoxin preparations with the complement system. | escherichia coli o89 lipopolysaccharide (lps) was treated with different doses of gamma irradiation (5, 10, 15, and 20 mrad). various biological activities such as lethal effect, decrease in arterial blood pressure in dogs, and interaction with the complement system were determined for the parent and irradiated preparations. irradiation of lps significantly and in a dose-dependent manner decreased its lethal and blood pressure-depressing effects along with its ability to activate the complement ... | 1977 | 326671 |
bactericidal activity of the normal, cell-free hemolymph of silkworms (bombyx mori). | cell-free hemolymph from silkworm (bombyx mori) larvae can kill escherichia coli b/sm. the bactericidal principle can be resolved into at least two factors. one is a lysozyme-like enzyme that can be absorbed on crab shell chitin and on bentonite, and the other (cofactor) is an anionic factor that is of low molecular weight, can pass through the chitin column and a carboxymethyl-cellulose column, and can be eluted from a diethylaminoethyl-cellulose column at mu = 0.15 and ph 7.5. egg-white lysozy ... | 1977 | 326674 |
isolation of cryptic plasmid deoxyribonucleic acid from kanagawa-positive strains of vibrio parahaemolyticus. | twelve strains of vibrio parahaemolyticus was examined for plasmid deoxyribonucleic acid (dna) by dye-buoyant gradient centrifugation. four kanagawa-positive strains, all isolated from the same outbreak of gastroenteritis, contained multiple plasmid species of cryptic function. however, three kanagawa-negative strains and five kanagawa-positive strains were not found to contain demonstrable plasmid dna. r-plasmids were successfully transferred from escherichia coli to v. parahaemolyticus. | 1977 | 326675 |
colonization of porcine intestine by enterotoxigenic escherichia coli: selection of piliated forms in vivo, adhesion of piliated forms to epithelial cells in vitro, and incidence of a pilus antigen among porcine enteropathogenic e. coli. | in contrast to k88-positive porcine enterotoxigenic escherichia coli (etec), k88-negative porcine etec strains did not adhere to isolated intestinal epithelial cells in vitro. however, they did adhere to intestinal epithelium in vivo. growth of one such etec (strain 987) in pig small intestine consistently yielded a greater percentage of piliated cells than did growth in vitro. this increase was demonstrable by electron microscopy, by change in colonial morphology, and by agglutination in specif ... | 1977 | 326676 |
reduction of reactivity of escherichia coli enterotoxins by intestinal mucosal components. | incubation studies involving rabbit and piglet small intestinal mucosal components and escherichia coli and vibrio cholerae enterotoxins were conducted at 37 and 4 degrees c. mucosal homogenate cytosol from rabbits did not significantly alter the reactivities of either cholera enterotoxin (ct) or e. coli labile enterotoxin (lt). however, mucosal homogenate cytosol from piglets was capable of neutralizing lt, though it had no effect on e. coli stable enterotoxin. lt became bound to piglet and rab ... | 1977 | 326677 |
pathogenesis of neonatal escherichia coli meningitis: induction of bacteremia and meningitis in infant rats fed e. coli k1. | escherichia coli k1 strains, isolated from human newborns with meningitis, were fed to pathogen-free sprague-dawley infant rats by an oral gastric tube. feeding of 10(3) to 10(11) organisms colonized the intestine of approximately 70% of the animals. at 5 days postfeeding of 3- to 5-day-old rats, bacteremia was detected in 60%, and meningitis occurred in 15% of bacteremic animals. colonization and bacteremia were age-related. rats 15 days old had only 19 colonization and 10% bacteremia, and thos ... | 1977 | 326679 |
action of hydrogen peroxide on degradation of dna after irradiation in escherichia coli. | hydrogen peroxide (h2o2), which produces breaks in cellular dna, has not hitherto been shown to cause degradation of dna. in this investigation it is shown that if transcription is blocked with rifampin, treatment with h2o2 causes degradation of dna to nearly the same extent as does gamma-radiation. further, if cells are given a treatment with h2o2 and incubated for 50 min, the amount of degradation in a second treatment is markedly less. this is attributed to the induction of the inhibitor of p ... | 1977 | 326708 |
the effect of u.v.-irradiation on lambda dna transcription. | the effect of u.v.-irradiation of template dna has been studied in vitro in the e. coli rna polymerase system with native and u.v.-treated lambda dna. lambda dna is more susceptible to u.v. than is calf-thymus dna, yet a residual activity is observed at a u.v. dose of 0-5+10(4) erg/mm2. from the kinetic analysis of the reaction and the incorporation of lambda 32p-labelled nucleoside triphosphates, it seems reasonable to conclude that u.v.-irradiation probably does not affect the dna initiation s ... | 1977 | 326709 |
the use of an escherichia coli lys- auxotroph to assay nutritionally available lysine in biological materials. | | 1977 | 326744 |
attempted elimination of plasmid-determined haemolysin, k88 antigen and enterotoxin from escherichia coli pathogenic for pigs. | | 1977 | 326745 |
dying of gamma-irradiated escherichia coli studied by the use of prophage. | loss of the biological activity of deoxyribonucleic acid in gamma-irradiated escherichia coli cells was studied. the study is based on two sets of experimental data: (i) post-irradiation heat inducibility of the cells whose chromosomes were "labeled" with the thermoinducible lambdaci857ind prophage, and (ii) post-irradiation capacity of nonlysogenic cells to promote growth of the unirradiated lambdaci857ind phage. the results show that, at the beginning of incubation after irradiation, the numbe ... | 1977 | 326751 |
characterization of methylated neutral amino acids from escherichia coli ribosomes. | the methylated neutral amino acids from both 30s and 50s ribosomal subunits of an escherichia coli k strain were characterized. the 50s ribosomal subunit contains three methylated neutral amino acids: n-monomethylalanine, n-monomethylmethionine, and an as yet unidentified methylated amino acid found in protein l11. both n-monomethylalanine and n-monomethylmethionine were found in protein l33. the amount of n-monomethylmethionine in this protein, however, is variable but not more than 0.25 molecu ... | 1977 | 326752 |
analysis of genetic recombination between two partially deleted lactose operons of escherichia coli k-12. | genetic recombination between a nontandem duplication of two partially deleted lactose operons (lacms286phi80diilacbk1) in escherichia coli k-12 has been examined. since the deletions were nonoverlapping, rare lactose-fermenting (lac+) recombinants occurred and were detected qualitatively on lactose tetrazolium agar indicator plates as white papillae growing on the surface of red colonies or quantitively on lactose minimal agar plates. formation of lac+ recombinants required the reca, recb, and ... | 1977 | 326755 |
properties of the relaxation complex of supercoiled deoxyribonucleic acid and protein of r plasmid nr1 in escherichia coli. | some properties of the supercoiled deoxyribonucleic acid (dna)-protein relaxation complex of the r plasmid nr1, which contains more than one origin for dna replication, were examined. the percentage of complexed nr1 molecules that can be converted to the relaxed (nicked) form appeared to be unaffected by the conditions under which the host cells were cultured. however, the percentage of supercoiled nr1 dna that can be relaxed was highly dependent on the method used to prepare the dna and the age ... | 1977 | 326756 |
inactivation and partial degradation of phosphoribosylanthranilate isomerase-indoleglycerol phosphate synthetase in nongrowing cultures of escherichia coli. | the stability of tryptophan biosynthetic enzyme activities was examined in cultures of repressor-negative (trpr) strains of escherichia coli k-12 incubated under conditions of nutrient starvation of chloramphenicol inhibition. the results show that four of the five activities examined are stable under most nongrowing conditions, whereas one activity, indoleglycerol phosphate (ingp) synthetase, carried by the trpc protein, is unstable under most conditions tested. phosphoribosylanthranilate (pra) ... | 1977 | 326757 |
control of protein synthesis in escherichia coli: analysis of an energy source shift-down. | the energy source shift-down described in the preceding paper (molin et al., j. bacteriol. 131: 7-17, 1977) was used to study the effects of shift-down on protein synthesis. the overall rate of protein synthesis was reduced immediately, and to the same extent, in stringent and relaxed strains. the primary effect of the shift was a slowing down of the polypeptide chain growth rate, a finding not previously reported. in stringent strains the normal, preshift rate was reestablished within 2 to 3 mi ... | 1977 | 326760 |
effect of transient lambda prophage induction on ultraviolet light resistance and recombination in escherichia coli. | transient induction of lambda prophage increases the ultraviolet light resistance of most exponentially growing escherichia coli lysogens. resistance is increased in wild-type, recb, recb recc, recb recc recf, and recb recc recl hosts. no enhancement in reca lysogens was found, nor was there enhancement in stationary cultures. enhancement was dependent upon the lambdared recombination system. transient induction also increases the genetic recombination rate in recb lysogens as measured in hfr x ... | 1977 | 326761 |
metabolism of arginine-specific messenger ribonucleic acid in escherichia coli k-12. | ribonucleic acid-deoxyribonucleic acid (rna-dna) hybridization was employed for the determination of the level of messenger rna (mrna) transcribed from seven of the nine genes of the arginine regulon of escherichia coli k-12. the quantity of rna complexing with each of the separated dna strands of the arga, argf, arge, and argcbh operons carried on specialized transducing phages was measured. the derepressed:repressed ratio of mrna formed in vivo was found to vary between about 3 and 4 when meas ... | 1977 | 326762 |
morphological analysis of the division cycle of two escherichia coli substrains during slow growth. | morphological parameters of the cell division cycle have been examined in escherichia coli b/r a and k. whereas the shape factor (length of newborn cell/width) of the two strains was the same at rapid growth (doubling time, tau, less than 60 min), with decreasing growth rate the dimensions of the two strains did change so that b/r a cells became more rounded and b/r k cells became more elongated. the process of visible cell constriction (t period) lasted longer in b/r a than in b/r k during slow ... | 1977 | 326763 |
temperature-sensitive cell division mutants of escherichia coli with thermolabile penicillin-binding proteins. | the thermostability of the penicillin-binding proteins (pbps) of 31 temperature-sensitive cell division mutants of escherichia coli has been examined. two independent cell division mutants have been found that have highly thermolabile pbp3. binding of [(14)c]benzylpenicillin to pbp3 (measured in envelopes prepared from cells grown at the permissive temperature) was about 30% of the normal level at 30 degrees c, and the ability to bind [(14)c]benzylpenicillin was rapidly lost on incubation at 42 ... | 1977 | 326764 |
genetics of the relb locus in escherichia coli. | a mutant of escherichia coli with a delayed relaxed phenotype very similar to that of a previously described relb mutant has been obtained using a new selection procedure. the mutation giving rise to this phenotype has been shown to map at 34.5 min and to be 12% cotransducible with man. it is recessive, revertible, and most likely an allele of the relb gene. | 1977 | 326765 |
identification of lipopolysaccharides and phospholipids of escherichia coli in polyacrylamide gels. | polyacrylamide gel electrophoresis of unfractionated lysates of radioactively labeled cells resolves not only proteins and polynucleotides into discrete bands but also cellular lipopolysaccharides and phospholipids. this allows a determination of the intracellular amounts of all of these macromolecules. in addition, this technique is sensitive enough to detect mutational alterations in lipopolysaccharide structure. polyacrylamide gel electrophoresis is herein shown to be a useful tool for invest ... | 1977 | 326766 |
mucopeptide biosynthesis by minicells of escherichia coli. | minicells produced by escherichia coli chi925 incorporated amino acids and n-acetyl-d-glucosamine into mucopeptide. | 1977 | 326767 |
fine-structure mapping and complementation analysis of the escherichia coli cysb gene. | sixty-two point mutations were isolated in escherichia coli by means of transduction with mutagenized phage p1. twenty-two deletions extending into cysb but able to recombine with at least some of the point mutations were isolated on a transmissible e. coli plasmid. mapping of the point mutations against the deletions divided the former into 16 deletion groups. nine merodiploids were constructed in which the chromosome carried one of the three point mutations most distal to the trp operon and in ... | 1977 | 326769 |
expression of r-plasmid functions during anaerobic growth of an escherichia coli k-12 host. | the normal habitat of enteric bacteria is largely anaerobic. expression of the three characteristic properties of r-plasmids, drug resistance, vegetative replication, and fertility, was therefore studied in escherichia coli k-12 during anaerobiosis. replication and drug resistance functions were not altered in the 45 r-plasmids studies, whereas the expression of fertility varied considerably among different r-plasmids during anaerobiosis. the r-plasmids could be divided into three groups, one sh ... | 1977 | 326771 |
control of ribosome synthesis in escherichia coli: analysis of an energy source shift-down. | the rate of ribosome synthesis and accumulation in escherichia coli during the transition after an energy source shift-down was analyzed. the shift was imposed on cultures of stringent and relaxed strains growing in glucose minimal medium by the addition of the glucose analogue alpha-methylglucoside. in the stringent strain, ribosome synthesis was almost instantaneously reduced after the shift, whereas the relaxed strain exhibited a more gradual response. the rate of messenger ribonucleic acid ( ... | 1977 | 326772 |
r-plasmid transfer and its response to nalidixic acid. | the conjugational transfer efficiency of 41 wild-type r-plasmids was studied in escherichia coli k-12. type i r-plasmids were transferred at comparatively high and rather uniform frequencies, whereas type f r-plasmids showed less uniform and, on average, somewhat lower transfer frequencies. r-plasmids not mediating sensitivity to f-, i-, or n-specific phages showed moderate transfer frequencies, and type n r-plasmids showed very low transfer frequencies. various lines of evidence suggest that a ... | 1977 | 326773 |
release factor binding to ribosome requires an intact 16 s rrna 3' terminus. | cloacin df12 cleavage of escherichia coli f[3h]mettrna-aug-ribosome complexes affects this substrate for in vitro peptide chain termination. codon-directed release factors' (rf) 1 and 2 release of f[3h]methionine is inhibited by cloacin. since cloacin inhibits rf1 and -2 binding to ribosomes but not rf-directed f[3h]methionine release from f[3h]met-trna-aug-ribosome complexes when reactions contain 20% ethanol, we conclude that cloacin df 13 inhibits formation of the termination codon recognitio ... | 1977 | 326774 |
mutants of escherichia coli defective in membrane phospholipid synthesis. effects of cessation and reinitiation of phospholipid synthesis on macromolecular synthesis and phospholipid turnover. | | 1977 | 326776 |
interactions of tryptophan synthetase subunits in escherichia coli containing mutationally altered beta2 subunits. | | 1977 | 326778 |
studies of the lipid phase transitions of escherichia coli by high sensitivity differential scanning calorimetry. | high sensitivity adiabatic differential scanning calorimetry was performed on lipids, membrane vesicles, and whole cells of escherichia coli enriched in particular unsaturated fatty acids by genetic means. information concerning the shape of the transition is discussed. transitions with an asymmetric shape reminiscient of a second order transition were observed. comparison between the lipid transition observed in whole cells, membrane vesicles, and extracted lipids enriched in elaidate reveal so ... | 1977 | 326779 |
novel properties of escherichia coli exonuclease iii. | the specificity of hydrolysis of polynucleotide termini by escherichia coli exonuclease iii was studied with the use of oligothymidylate annealed to polydeoxyadenylate. the size of the products after 3' leads to 5'-hydrolysis of 5'-labeled substrate is temperature-dependent. at 25 degrees the enzyme can hydrolyze a polynucleotide chain up to the last 5'-terminal dinucleotide. a gradation of higher 5'-terminal oligonucleotides of defined chain lengths is produced after limit digestion by the enzy ... | 1977 | 326780 |
study of the transfer rnas coded by t2, t4, and t6 bacteriophages. | t2, t4, and t6 bacteriophage trnas coding for arginine, leucine, proline, isoleucine, and glycine were isolated under conditions of short term and long term infection of escherichia coli b cells. the corresponding phage trna species were examined for sequence homology by rna-dna hybridization analysis and by their relative behavior on reversed phase chromatography. the results indicate that all three t-even phages code for similar trna species; however, some trna species are homologous, others a ... | 1977 | 326783 |
amino acid sequence of the l-arabinose-binding protein from escherichia coli b/r. | the amino acid sequence of the l-arabinose-binding protein of escherichia coli b/r was determined by sequenator analyses of reduced and s-pyridylethylated l-arabinose-binding protein and fragments derived by chemical and enzymatic cleavage of the native protein. the fragments were the products of cleavage by cyanogen bromide. bnps-skatole, hydroxylamine, mild acid hydrolysis, limited trypsin digestion, chymotrypsin subdigestion, and subdigestion with staphylococcus aureus protease v8. the cooh-t ... | 1977 | 326784 |
the 2.8-a resolution structure of the l-arabinose-binding protein from escherichia coli. polypeptide chain folding, domain similarity, and probable location of sugar-binding site. | | 1977 | 326785 |
laboratory assessment of physical and chemical methods of preserving urine specimens. | three methods of preserving simulated specimens of urine were studied with six test strains of bacteria. viable counts were measured by a surface viable count and by the filter-paper-strip method during a holding period of 72 hours. refrigeration at approximately 4 degrees c was effective and reliable. boric acid (1-8%) at room temperature was toxic for the strain of escherichia coli at a density of 10(7) cfu/ml but this may not be significant at the higher concentration of bacterial cells often ... | 1977 | 326817 |
identification of rna as a complement inhibitory component in an extract of ehrlich ascites tumor cells. | a factor capable of inhibiting complement was obtained from intact ehrlich ascites tumor cells by mild extraction with phosphate-buffered saline (pbs). the inhibitor caused a decrease in extent of lysis of eac14 with a concomitant extension of tmax. ea, eac1, eac4 and eac142 were all less susceptible to complement-mediated lysis after treatment with the tumor cell extract. partial purification of a complement inhibitor was accomplished. the inhibitor was rich in rna and its activity was totally ... | 1977 | 326959 |
release of phospholipids from complement-mediated lesions on the surface structure of escherichia coli. | when varying numbers of sensitized, 14c-labeled bacteria were treated with a certain amount of complement, in a fixed reaction volume, 14c compounds were liberated into the surrounding medium in proportion to the number of the bacteria, whereas the amount of the phospholipids liberated was constant regardless of the number of the bacteria even in the range of relative excess of complement. since it is conceivable that a certain amount of complement might form a fixed number of lesions on the su ... | 1977 | 326965 |
biochemical genetics of the alpha-keto acid dehydrogenase complexes of escherichia coli k12: isolation and biochemical properties of deletion mutants. | mutants of escherichia coli k12 with deletions in the nadc-lpd region of the chromosome were obtained for use in studies on the expression of the ace (pyruvate dehydrogenase complex, specific components) and lpd (lipomide dehydrogenase) genes. these were isolated by selecting spontaneous arop mutants (lacking the general aromatic amino-acid permease and thus resistant to inhibitory aromatic amino-acid analogues) and screening for auxotrophy due to deletions extending into neighbouring genes. fro ... | 1977 | 327021 |
induction of cell division in a temperature-sensitive division mutant of escherichia coli by inhibition of protein synthesis. | synchronous cells of the thermosensitive division-defective escherichia coli strain maci (diva) divided at the restrictive temperature (42 degrees c) if they were allowed to grow at 42 degrees c for a certain period before protein synthesis was inhibited by adding chloramphenicol (cap) or rifampicin. the completion of chromosome replication was not required for such diva-independent division. synchronous cells of strain maci divided in the presence of an inhibitor of dna synthesis, nalidixic aci ... | 1977 | 327022 |
preliminary characterization of cell-free k99 antigen isolated from escherichia coli b41. | the k99 antigen of escherichia coli b41 was isolated by isoelectric precipitation from heated bacterial suspensions. chromatography and immunoabsorption experiments suggested that the mannose-resistant haemagglutinating activity of partially purified preparations of antigen was k99. the antigen was partially susceptible to bacterial proteases and was inactivated by periodate oxidation. haemagglutination inhibition experiments with sugars and absorption of k99 with antisera to human blood groups ... | 1977 | 327023 |
the influence of growth substrate and capacity for oxidative phosphorylation on respiratory oscillations in synchronous cultures of escherichia coli k12. | fluctuations in cell volume during exponential growth of escherichia coli k12 changed the effectiveness of the continuous-flow centrifugation method for preparing synchronous cultures. rates of oxygen uptake in synchronous cultures were measured using an electrode system open to the atmosphere. in synchronous cultures of both the parental strain and an adenosine triphosphatase-deficient mutant, which was incapable of oxidative phosphorylation, respiration rates doubled during the cell cycle but ... | 1977 | 327024 |
properties of ppe1572(hys-raf), a plasmid governing hydrogen sulphide production and raffinose fermentation in escherichia coli. | | 1977 | 327025 |
heat-stable enterotoxigenic escherichia coli and necrotizing enterocolitis: lack of an association. | during an outbreak of diarrhea in a special care nursery caused by heat-stable enterotoxigenic escherichia coli (serotype 078:h11:k80), nine (4.3%) of the 205 infants in the nursery developed necrotizing enterocolitis. cases of necrotizing enterocolitis were not significantly more common in infants colonized or infected with these organisms; heat-stable enterotoxigenic e. coli was isolated from 5(56%) of nine cases of necrotizing ecterocolitis and from 27(38%) of the 71 infants without necrotizi ... | 1977 | 327052 |
spectrophotometry as a tool for assaying endotoxins. | a spectrophotometric method is reported for assaying endotoxins over a wide concentration range, including low parts per billion levels. five solution of endotoxins. escherichia coli 0127:b8, escherichia coli 055:b5, salmonella abortus-equi, salmonella enteritidis, and shigella flexneri, were examined. each exhibited an absorption maximum at 259 nm, but the absorptivities differed in each case. thus, rigorous quantification requires that the identity of the endotoxin be known. the uv absorbance ... | 1977 | 327056 |
physical properties of ribosomal protein s1 and its interaction with the 30 s ribosomal subunit of escherichia coli. | | 1977 | 327076 |
transcription termination at the end of the tryptophan operon of escherichia coli. | | 1977 | 327077 |
coding properties of an ochre-suppressing derivative of escherichia coli trnaityr. | | 1977 | 327078 |
identification of neighbouring proteins in escherichia coli 30 s ribosome subunits. | | 1977 | 327079 |
in vitro system that synthesizes circular viral dna of bacteriophage phi x 174. | an extract prepared from escherichia coli cells infected with phi chi 174 bacteriophage was capable of incorporating dttp into phage-specific dnas in vitro. the synthesized dnas were associated with proteins and sedimented with s values of 20, 50, and 90 in a sucrose gradient sedimentation. dna isolated from 20s material was open circular replicative form (rf), dna in 50s material was replicative-form dna with an extended single-stranded viral dna that ranged up to one genome in length, and dna ... | 1977 | 327087 |
isolation of specialized lambda transducing bacteriophages for flagellar genes (fla) of escherichia coli k-12. | specialized transducing lambda phages carrying the region iii flagellar genes (fla) of escherichia coli k-12 were isolated by a new method. a strain carrying both a cryptic lambda prophage near the his genes and a deletion of the attlambda gene was used as a starting strain. the lysogen of lambdaci857pga18-bio69 was isolated in which the prophage was integrated within the lambda cryptic genes by means of recombination with the residual lambda dna. the strains with deletions starting within the p ... | 1977 | 327089 |
glucose kinetics in dogs following a lethal dose of endotoxin. | the effects of a lethal dose of escherichia coli endotoxin on the glucose kinetics and cardiovascular responses of conscious dogs were studied. the plasma glucose level fell steadily after endotoxin administration to severely hypoglycemic levels preterminally. the fall in plasma glucose appeared to be due primarily to an increased tissue uptake in the early phase, whereas decreased hepatic glucose output also contributed in the later, preterminal phases. | 1977 | 327195 |
outbreaks of acute enteritis due to heat-stable enterotoxin-producing strains of escherichia coli. | | 1977 | 327216 |
synthetic disaccharide-protein antigens for production of specific 04 and 09 antisera for immunofluorescence diagnosis of salmonella. | the synthetic disaccharides abequose 1 leads to a 3 mannose and tyvelose 1 leads to a 3 mannose, representative of salmonella o-antigen 4 and 9 respectively, were covalently linked to bovine serum albumin (bsa) . antisera from rabbits immunized with these immunogens were used in indirect immunofluorescence assay for the identification of group b (o-antigen 4) and d (o-antigen 9) salmonella. a total of 1030 enteric bacterial strains were tested, including 207 group b and 55 group d salmonella. th ... | 1977 | 327249 |
mutagenic dna repair in escherichia coli. vi. gamma radiation mutagenesis in a tif-1 strain. | | 1977 | 327260 |
detection of messenger rna from the isoleucine--valine operons of salmonella typhimurium by heterologous dna-rna hybridization: involvement of transfer rna in transcriptional repression. | a hybridization assay using escherichia coli k-12 dna isolated from the specialized transducing bacteriophage gammaci857st68h80 dilv was used to examine the rate of synthesis of the messenger rna's (mrna) derived from the isoleucine-valine (ilv) gene cluster of salmonella typhimurium. in all cases examined, changes in ilv enzyme levels could be correlated with changes in the rate of synthesis of ilv mrna. several well characterized regulatory mutants of s. typhimurium had rates of synthesis of ... | 1977 | 327261 |
studies on the bipolar argecbh operon of e. coli: characterization of restriction endonuclease fragments obtained from gammadargecbh transducing phages and a cole1 argecbh plasmid. | the isolation of a new type of gamma transducing phage carrying the bipolar argecbh operon of e. coli k12 is described. the argecbh segment is inserted in the phage in a direction which is opposite from that of previously isolated argecbh-carrying phages. a cole1 argecbh plasmid has been constructed. dna fragments resulting from digestion of these genetic elements with eco ri and hind iii restriction enzymes have been characterized by agarose gel electrophoresis and electron microscopy, includin ... | 1977 | 327264 |
analysis of the phase variation in lambda reduced immunity lysogens. | two distinct phases characterized by different levels of immunity that appear in some e. coli strains lysogenic for reduced immunity mutants of bacteriophage lambda are identified as single and tandem double lysogens respectively on the basis of dna-dna hybridization experiments and the requirement of the phage xis function for the transition from a single to a double, and of the host reca function for the transition from a double to a single lysogen (in a xis- condition). rim lysogens with a fu ... | 1977 | 327265 |
altered dihydrofolate reductase in fol regulatroy mutants of escherichia coli k12. | three spontaneous fol regulatory mutants contain dihydrofolate reductase molecules which differ in physical properties from enzymes of their parent strains. the enzymes were purified over 100-fold by affinity chromatography and were shown to differ in vitro in thermolability and in affinity for trimethoprim, a competitive inhibitor of the enzyme. these results indicate that some fol regulatroy mutations occur in the structural gene for dihydrofolate reductase. | 1977 | 327267 |
physical and genetic studies with restriction endonucleases on the broad host-range plasmid rk2. | the cleavage map of the plasmid rk2 was determined for the five restriction endonucleases ecori, hindiii, bamh-i, sali and hpai. dna has been inserted into several of these sites and cloned in escherichia coli. efforts to obtain derivatives of rk2 reduced in size by restriction endonuclease digestion of the plasmid were not successful and indicated that genes required for the maintenance of this plasmid in e. coli are not tightly clustered. an rk2 derivative possessing an internal molecular rear ... | 1977 | 327269 |
control of ribosomal rna synthesis in escherichia coli. ii. ribosomal rna synthesis in isolated nucleoids. | the effect of amino acid-starvation on the transcription in vitro of overall rna and ribosomal rna was investigated using nucleoids prepared from the exponentially growing and the amino acid-starved cells of rel+ and rel- strains of escherichia coli. in this system, the synthesis of rna is exclusively due to elongation of the chains which have been initiated in vivo. the amounts of overall and ribosomal rna synthesized per unit of dna in the nucleoids were analyzed for each preparation. the foll ... | 1977 | 327272 |
control of ribosomal rna synthesis in escherichia coli. iii. cytoplasmic factors for ribosomal rna synthesis. | the ribosomal rna synthesis in a cell-free system containing the nucleoids and the cytoplasmic fraction prepared from escherichia coli cells has been investigated. the addition of the "4s" fraction from the cytoplasm to the isolated nucleoids induces rna synthesis by a new chain initiation. in this system a preferential initiation or rrna chains occurs. the experimental results suggest that the 4s fraction contains at least two activities, one for releasing rna-polymerases from the nucleoids, an ... | 1977 | 327273 |
restriction endonuclease mapping and mutagenesis of the f sex factor replication region. | the plasmids psc138 and pml31 each contain the ecori-generated f5 replicator fragment of the conjugative plasmid f in addition to an ecori fragment encoding antibiotic resistance: ampicillin resistance derived from staphylococcus aureus in psc138 and kanamycin resistance from escherichia coli in pml31. we have mapped one hindiii and two bamhi restriction sites in the f5 region of these plasmids and one hindiii site in the antibiotic resistance region of each plasmid. the hindiii site in the km r ... | 1977 | 327274 |
a specialized transducing lambda phage carrying the escherichia coli genes for phenylalanyl-trna synthetase. | a lambda phage has been isolated which specifically transduces the escherichia coli phes and phet genes coding for the alpha and beta subunits of the phenylalanyl-trna synthetase (prs). this phage transduces with high frequency (i) several temperature-sensitive prs mutants to thermoresistance and (ii) a p-fluorophenylalanine resistant prs mutant to sensitivity against this amino-acid analog. the in vitro prs activities of such lysogens suggest that the alpha and beta subunits coded by the transd ... | 1977 | 327276 |
replication of fpoh+ plasmid in mafa mutants of escherichia coli defective in plasmid maintenance. | a class of f' plasmids, designated fpoh+, was previously shown to be able to replicate extra-chromosomally on hfr strains by virtue of carrying the specific site or region poh+ (permissive on hfr) of the e. coli chromosome (hiraga, 1975, 1976a). these plasmids were now found to replicate on e. coli mafa mutants (mafa1 and mafa23) that cannot support vegetative replication of f and some other f-like plasmids. the derivatives of fpoh+ that have lost the poh+ site, on the other hand, failed to repl ... | 1977 | 327277 |
further temperature-sensitive mutants of escherichia coli with altered ribosomal proteins. | various alterations in ribosomal proteins were detected in forty-one mutants of e. coli isolated as temperature-sensitive mutants. out of these, six are new classes of mutants harboring mutations in proteins s3, l5, l7 (l12), l29, l30 and l33. one of them apparently lacks protein l7 of the large subunit. these mutants together with those reported previously (isono et al., 1976) total one hundred and one ribosomal mutants in thirty different proteins. | 1977 | 327280 |
kinetics of ribosome synthesis during a nutritional shift-up in escherischia coli k-12. | the rates of total protein synthesis, polyribosome formation and 70s ribosome accumulation were measured following a nutritional shift-up of escherichia coli k-12. changes in ribosome content and distribution during the shift-up were measured by examining the total cellular content of free and polysome-associated ribosomes using a sensitive double isotope labeling method. the kinetics of ribosomal subunit formation and the biosynthesis of subunit protein and rna species were also defined. the re ... | 1977 | 327281 |
cold-sensitive growth of a mutant of escherichia coli with an altered ribosomal protein s8: analysis of revertants. | 26 cold-resistant revertants of a cold-sensitive escherichia coli mutant with an altered ribosomal protein s8 were analyzed for their ribosomal protein pattern by two-dimensional polyacrylamide gel electrophoresis. it was found that 16 of them had acquired the apparent wild-type form of protein s8, one exhibits a more strongly altered sc than the original mutant and two revertants regained the wildtype form of s8 and, in addition, possess alterations in protein l30. the ribosomes of the residual ... | 1977 | 327286 |
the use of rec-bacteria for testing of carcinogenic substances. | a series of rec-escherichia coli strains were tested for their sensitivity to four known carcinogenic compounds by examination of a zone of inhibited bacterial growth around a central well containing the test chemical. the mutants reca-, recb-, recc-, and reca- recb- recc- were all more sensitive to the mutagens than the parental strain ab1157. the recb- recc- strain was examined with a larger series of compounds and was found to respond to many of the substances in a similar way as the salmonel ... | 1977 | 327303 |
the mutagenic action of nitroimidazoles. ii. tinidazole, ipronidazole, panidazole and ornidazole. | the 5-nitroimidazoles tinidazole (fasigyn), ipronidazole (ro-7-1554), panidazole and ornidazole (tiberal, ro-7-0207) in concentrations of 0.02--1 mm per liter increased the mutation frequency of klebsiella pneumoniae. escherichia coli k12 and citrobacter freundii to streptomycin resistance, including streptomycin dependence, in luria and delbrück's fluctuation test. at low concentration (0.1 mm), the increase of the mutation frequency caused by each compound was nearly the same, i.e. 3--4 times ... | 1977 | 327306 |