| isolation of escherichia coli mutants defective in enzymes of membrane lipid synthesis. | a new method has been developed which permits the rapid screening of e. coli colonies for mutants with defective enzymes of phospholipid metabolism. in this procedure, a disc of filter paper is pressed down on an agar plate containing several hundred colonies of mutagen-treated cells, after which the paper is lifted off. in the process the colonies are transferred to the paper, giving rise to a replica print of the master plate. the few cells from each colony left on the master keep growing in t ... | 1975 | 49056 |
| effects of dihydrostreptomycin on ribosome function in vivo: lack of correlation between changes in ribosome patterns and growth. | in vivo treatment of susceptible escherichia coli cultures with low concentrations of dihydrostreptomycin leads to a decline in polysomes and a corresponding increase in 70s particles which behave as run-off ribosomes, as well as free 30s and 50s subunits. we have examined the timing and extent of these effects on ribosomes and compared them to the effects of this antibiotic on growth and protein synthesis. we have shown that no changes in ribosome distribution are observed until growth inhibiti ... | 1975 | 49170 |
| the inhibition of phospholipid synthesis in escherichia coli by phenethyl alcohol. | the kinetics of lipid metabolism during phenethyl alcohol treatment of escherichia coli were examined. phenethyl alcohol at a non-bacteriostatic concentration reduces the accumulation of [32-p] phosphate into phospholipids and alters the phospholipid composition of the cell membrane. the changes in phospholipid composition are a result of the inhibitory effect of phenethyl alcohol on the rates of synthesis of the individual phospholipids. the inhibition in the rate of phosphatidylethanolamine sy ... | 1975 | 49194 |
| epidemiology of escherichia coli k1 in healthy and diseased newborns. | although at least 100 different escherichia coli capsular antigens have been recognised, strains possessing the k1 antigen are responsible for 77% of neonatal e. coli meningitis cases. k1 strains were found in 20-40% of rectal swab cultures from healthy infants, children, and adult women. vertical transmission from mother to infant was the most common means of aquiring k1 organisms in term infants. premature babies in a nursery with little maternal contact aquired k1 strains later then did te ... | 1975 | 49468 |
| diarrhoea associated with heat-stable enterotoxin-producing strains of escherichia coli. | five patients who developed acute watery diarrhoea while travelling in mexico in october, 1974, were found to have enterotoxigenic escherichia coli in their stool which produced heat-stable enterotoxin (s.t.) without producing heat-labile enterotoxin (l.t.). these s.t.-only e. coli, which have previously been described as causing diseases in animals, must now be regarded as pathogenic for humans as well. | 1975 | 49793 |
| maturation of a hypermodified nucleoside in transfer rna. | e. coli c6 rel- met- cys- was cultured in a fully supplemented medium and in media lacking cysteine or methionine. trna isolated from the three cultures containted, respectively, a normal complement of modified nucleosides; a deficiency in thiolated nucleosides and a deficiency in methylated nucleosides. both sulfur-deficient trna and methyl-deficient trna contained large amounts of n-6- (delta-2-isopentenyl) adenosine and small amounts of the 2-methylthio derivative. methyl-deficient trna conta ... | 1975 | 49880 |
| [inhibition of viral reverse transcriptase and leukemogenesis by modified nucleic acids (author's transl)]. | inhibition of dna polymerase from oncorna viruses by a new class of macromolecular inhibitors is reported. the macromolecule, designated as mercaptopolycytidylic acid (mpc), is a chemically modified polycytidylic acid containing 5-sh cytidylic bases in the polymerase. partially thiolated polycytidylic acids (mpc i-iii, containing 1.7%, 3.5%, and 8.6% 5-mercaptocytidylate units, respectively) inhibited the dna-polymerase of friend leukemia virus (fvl) in the endogenic reaction as well as in the p ... | 1975 | 49986 |
| antigenic, antibiotic and phage receptor activity of proteins from sh. boydii 15. | the analyzed strain of sh. boydii 15 induced antibodies against the somatic antigen conjugate, as in most shigella. except for the proteinic carrier of the somatic antigen, only a few of the homologous proteinic determinants induced corresponding antibodies; these were illustrated with the help of a serum to proteins from sh. sonnei. the proteins of sh. boydii 15 displayed a wide range of antibiotic activity against shigella, e. coli and salmonella. another aspect concerning the biological activ ... | 1975 | 49990 |
| aminoglycoside 3'-phosphotransferases i and ii in pseudomonas aeruginosa. | aminoglycoside 3'-phosphotransferases i and ii in three strains of pseudomonas aeruginosa were studied in comparison with those in two strains of r factor-carrying escherichia coli. the strain ti-13 of p. aeruginosa produced the former and strain h-9 the latter. strain b-13 produced the both enzymes. the 3'-phosphotransferases of type i in p. aeruginosa ti-13, b-13 and e. coli k12 j5 r11-2 were different from each other in chromatographic behavior, molecular weight, ph optimum, and ii. the 3'-ph ... | 1975 | 50310 |
| 5"-amino-3',4',5"-trideoxybutirosin a, a new semisynthetic aminoglycoside antibiotic. | 5"-amino-3',4',5"-trideoxybutirosin a (ix) was synthesized through a reaction series starting from 5"-amino-5"-deoxybutirosin a (ic), the key step being the treatment of its tetra-o-acetylpentakis-n-((phenylemthoxy)carbonyl)-3',4'-bis-o-(methylsulfonyl) derivative (vi) with zince-sodium iodide. compound ix inhibits enhanced antibacterial activities, including strains of pseudomonas aeruginosa and escherichia coli which are highly resistant to ic, butirosin or gentamicin. | 1975 | 50312 |
| synthesis of aminotrideoxybutirosin a, a chemically modified antibiotic active against butirosin-resistant bacteria. | 5"-amino-3',4'5"-trideoxybutirosin a (4) was synthesized by two routes starting from the known tri-o-acetyl-tetra-n-benzyloxycarbonyl-3",5"-o-cyclohexylidene-3',4'-di-o-mesylbutirosin a (5). introduction of amino function at c-5" was carried out by displacement of 5"-tosyloxy group with sodium azide either before or after 3',4'-deoxygenation. compound 4 shows outstanding activities against strains including pseudomonas aeruginosa and escherichia coli which are highly resistant to butirosin and 5 ... | 1975 | 50313 |
| characterization of bleomycin action on dna. | cleavage of sv40 dna by bleomycin was assayed quantitatively in vitro in the presence of various ppolynucleotides. sv40 dna was protected from bleomycin- duced cleavage by native or denatured dna of other origins, oly dg-c.poly dg-c, poly da-t.poly da-t and poly da-t (denatured) but not by trna of e. coli, apurinic acid, poly da, poly dt and various deoxyribooligonucleotides. various bleomycins and their derivatives and various fragments of bleomycin were tested for possible activity in cleavin ... | 1975 | 50314 |
| immunological study of anthranilate synthetase. | an immunological study of anthranilate synthetase (asase) has been initiated using quantitative precipitation, enzyme neutralization, and immunodiffusion methods. cross-reactivity of anthranilate synthetase-anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase (asase-prtase) from escherichia coli, klebsiella aerogenes, and salmonella typhimurium and asase from serratia marcescens and pseudomonas putida was detected with antibodies to ?e. coli trypsin-treated asase. cross-reactivit ... | 1975 | 50316 |
| long-lasting in vitro immune response to a distinct antigenic determinant of a bacterial protein. cyclic changes of antibody titer and affinity. | long-lasting (60 days or more) antibody responses in vitro by rabbit lymph node fragments to a distinct determinant of escherichia coli beta-d-galactosidase were obtained by supplementing culture medium with fetal calf and horse serum. antibodies released in the supernatant were removed every 3rd to 5th day together with the spent medium, without pooling to minimize intermixing of molecules synthesized far apart in time. antibody titer, association constant, and heterogeneity index were measured ... | 1975 | 50342 |
| ultrastructural studies on the inner and outer membranes of an unsaturated fatty acid auxotroph of escherichia coli. | | 1975 | 50456 |
| influence of oestrogen on experimental pyelonephritis caused by escherichia coli. | strains of escherichia coli isolated from patients with suspected pyelonephritis had a strong predilection for growth in kidney tissue. viable bacterial counts in experimentally infected mice showed that after 96 hours approximately 98% of the total-body count was found in the kidney. strains of e. coli isolated from cases of gastroenteritis in man and animals had little or no tendency to grow in the kidney. treatment of male and female mice with oestrogen significantly enhanced the growth of "p ... | 1975 | 50504 |
| allogeneic radiation chimeras. long-term studies. | lethally irradiated mice protected with allogeneic fetal liver cells or with syngeneic or allogeneic marrow and spleen cells treated with antisera to mouse immunoglobulins or to the t cell-associated theta antigen and their controls were observed for up to 750 days. the best survival rates were found in the large groups given syngeneic marrow and spleen or allogeneic fetal liver cells (70-85% 700-day survival); in contrast, 43% of the group injected with allogeneic cells treated with anti-theta ... | 1975 | 50655 |
| [bacterial cytostimulation by specific antibodies (author's transl)]. | antibodies bound to the surface of escherichia coli cells stimulate the rate of growth of these bacteria in proportion to their quantity. this "cytostimulation" of the bacteria is confirmed by (1) the increase in optical density, (2) colony counts and (3) increase in the beta-galactosidase activity of a constitutive strain. this action can be amplified by overlaying the antibodies bound to the bacteria, with anti-antibodies. the cytostimulation is accompanied by an increase of the ratio in phosp ... | 1975 | 50758 |
| proceedings: synthesis in vitro of escherichia coli carbamoylphosphate synthetase. | | 1975 | 50802 |
| reduced nicotinamide adenine dinucleotide dependent reduction of fumarate coupled to membrane energization in a cytochrome deficient mutant of escherichia coli k12. | escherichia coli sasx76 does not form cytochromes unless supplemented with 5-aminolevulinic acid. it can grow anaerobically on glycerol and dl-glycerol 3-phosphate in the absence of 5-aminolevulinic acid with fumarate but not with nitrate as the terminal electron acceptor. cytochrome-independent nadh oxidase, glycerol 3-phosphate- and nadh-fumarate oxidoreductase activities are induced by anaerobic growth on a glycerol-fumarate medium. the pathway of electrons from substrate to fumarate involves ... | 1975 | 50861 |
| inhibition of purified dna polymerase of rna tumor viruses by fluoranthene derivatives and analogues of tilorone hydrochloride. | at concentrations of 7 times 10(-6) to 7 times 10(-5) m, derivatives consisting of the polycylic ring structures fluoranthene, fluorenone, fluorene, anthraquinone, xanthenone, and dibenzofuran with appropriate amine side chains inhibited by over 90% the purified rna-directed dna polymerase of avian myeloblastosis virus acting on poly(deoxyadenylate-deoxythymidylate) [poly(da-dt)]. of these, only the fluoranthene derivatives were strong inhibitors of the viral dna polymerase directed by polyadeny ... | 1975 | 51087 |
| micrococcal urinary-tract infections in young women. | in a prospective study in young women, novobiocin-resistant subgroup-3 micrococci were the second commonest cause, after escherichia coli; of acute urinary infections. proteus mirabilis was the only other causative organism. symptoms, pyuria, or possible aetiological factors were the same in micrococcal and coliform infections. the infecting micrococcus "biotype" was only rarely found among the normal flora of the genitourinary tract of young women, though other micrococci and staphylococci were ... | 1975 | 51404 |
| [immunochemistry of the surface antigens of e. coli]. | | 1975 | 51643 |
| mechanism of action of rifamazine, a member of a new class of (dimeric) rifamycins. | 1. rifamazine (af/rp) a dimeric rifamycin, is active against bacterial dna-dependent rna polymerase and against viral rna-dependent dna polymerase. 2. rifamazine is active also against dna-dependent rna polymerase extracted from rifampicin-resistant mutants of escherichia coli. it does not interfere with enzyme-template interaction or with rna elongation. it blocks initiation. 3. a comparison is made between the mechanism of action of rifamazine and that of rifampicin, and of af/013 (octyloxime ... | 1975 | 51795 |
| alteration of the antibody response to escherichia coli o antigen in mice by prior exposure to various somatic antigens. | in the present study in mice we used the jerne plaque assay to compare the immunity enhancing potential of different gram-negative bacteria with special regard to their endotoxin. the results confirm the recent finding that injection of escherichia coli bacteria of various serotypes may enhance the igg antibody response to the o antigen of a serologically unrelated e. coli strain injected subsequently, but may suppress the igm antibody formation. the o antibodies formed were of low avidity but w ... | 1975 | 51829 |
| macromolecular synthesis in streptomyces antibioticus: in vitro systems for aminoacylation and translation from young and old cells. | in vitro systems for the aminoacylation of transfer ribonucleic acid (trna) and for polypeptide synthesis have been constructed from young (12-h cultures, not producing actinomycin) and old (48-h cultures, producing actinomycin) cells of streptomyces antibioticus. when escherichia coli aminoacyl-trna synthetases were used to acylate s. antibioticus trna's, it was observed that, per absorbance unit of trna, the trna's from 48-h cells had a lower ability to accept the amino acids, leucine, serine, ... | 1975 | 51847 |
| bacterial antigen and acid phosphatase in macrophages in experimental pyelonephritis. | experimental retrograde e. coli pyelonephritis was produced in rats. the study covered the period from 6-24 hours up to 6 months. macrophages in the renal tissue were studied using immunofluorescence staining for bacterial e. coli antigen and histochemical staining for aicd phosphatase. a comparison of sections stained according to the two methods showed that antigen-containing macrophages in nearly all cases yielded a positive reaction for acid phosphatase. on the other hand, in several kidneys ... | 1975 | 52278 |
| [electron microscopic study of the localization of penicillin acylase in e. coli cells]. | the paper describes the studies on definition of penicillinacylase localizations in the cells of e. coli with the help of ferritin labeled immune sera and electron microscopy. both the intact cells and the cells treated with the substances affecting the cell wall intactness were used. the study showed relation between penicillinacylase and the surface structures of the cell, i.e. the cell wall and the periplasmic areas. it was found that penicillinacylase got into the environmental medium with t ... | 1975 | 52342 |
| covalent lipoprotein from the outer membrane of escherichia coli. | | 1975 | 52377 |
| action of bleomycin on the bacteriophate t7 infection. | a decrease in production of bacteriophage t7 was observed in bleomycin-treated escherichia coli b cells. bleomycin was found to shorten the eclipse in phage growth. a t7 early gene product, the t7-specific rna polymerase which catalyzed the transcription of late gene appeared more rapidly in the bleomycin-treated cells than in the non-treated cells. the rate of phage adsorption increased to some extent in drug-treated cells. a possible mechanism to explain the mode of action of bleomycin is disc ... | 1975 | 52650 |
| antibodies as probes for detection of conformational changes in proteins. a model study with the alkaline phosphatase of escherichia coli. | | 1975 | 52715 |
| photobiological behaviour of bacteria and phages supplemented with aza-analogoues of nucleic acid bases. | the photochemical stability of anomalous nucleic acid bases of the azatype, 5-azacytosine (i), 5-azacytidine (ii), 6-azacytosine (iii), 6-azacytidine (iv), 6-azathymine (v), 6-azauracil (vi), and 8-aza-adenine (vii) to u. v. light of the wavelength 254 nm differs from the u. v. stability of the normal constituents. changes of the u.v. inactivation of escherichia coli k12 c600, e. coli b, bacillus cereus, as well as e. coli phages gamma cb2 and gamma b2b5 supplemented with azaderivatives prior to ... | 1975 | 52947 |
| specificity of the antiviral agent calcium elenolate. | calcium elenolate, an antiviral agent which inhibits reverse transcriptases, inhibits the growth of chicken embryo fibroblast cells, as well as echerichia coli and bacillus subtilis strains. the drug in vitro inhibits e. coli deoxyribonucleic acid (dna) polymerase ii and dna polymerase iii holoenzyme, as well as several unrelated enzymes. the usual dna polymerase assay components, with the exception of spermidine, have no effect on the observed inhibition. inhibition of dna polymerase ii by the ... | 1975 | 53031 |
| mode of inhibition of herpes simplex virus dna polymerase by phosphonoacetate. | phosphonoacetate is a highly specific inhibitor of herpes simplex virus-induced dna polymerase. sensitivity of herpesvirus type 1 or type 2 induced dna polymerase to the drug was similar. however, dna polymerases from other sources such as the host cells (wi-38), micrococcus luteus, and hepatitis b virus were highly resistant. in addition, escherichia coli rna polymerase and reverse transcriptase of rous sarcoma virus were also insensitive to the drug. enzyme kinetic studies showed that inhibiti ... | 1975 | 53071 |
| letter: serotyping of enteropathogenic escherichia coli. | | 1975 | 53403 |
| mucosal adherence of human enteropathogenic escherichia coli. | an in-vitro assay system has been developed to measure bacterial adhesion to the mucosa of human fetal small intestine. two strains of escherichia coli that are proven human enteropathogens (e.p.e.c.) have been shown to adhere in large numbers, compared with control organisms. the attachment mechanism is species specific and is not caused by common fimbriae. mucosal adhesion may be as important as enterotoxin production or invasiveness in determining the virulence of some strains of human e.p.e. ... | 1975 | 53431 |
| letter: escherichia coli k1. | | 1975 | 53576 |
| role of heat-labile toxigenic escherichia coli and reovirus-like agent in diarrhoea in boston children. | 61 boston children aged five years or less with acute diarrhoea were studied for evidence of infection with escherichia coli strains that produce heat-labile enterotoxin (l.t.) or with a reovirus-like agent associated with childhood gastroenteritis. this represented the first evaluation of the prevalence of disease produced by these two agents in the same population. e. coli, isolated from acute-phase stool specimens, were tested in adrenal-cell tissue-culture and adult-rabbit ileal-loop assays ... | 1975 | 53600 |
| enterotoxigenic escherichia coli and idiopathic diarrhoea in bangladesh. | faecal escherichia coli from bangalee patients with idiopathic diarrhoea were tested in the chinese hamster ovary cell (c.h.o.) assay to detect production of thermolabile enterotoxin (l.t.). c.h.o-positive e. coli produce both l.t. and a thermostable toxin (s.t.). c.h.o.-positive strains were found in 19.2% of all cases and in 70% of the most severely ill patients with non-vibrio cholera. e. coli which produce s.t. alone were identified in a third of the c.h.o.-negative cases. enterotoxigenic e. ... | 1975 | 53601 |
| editorial: e. coli enteritis. | | 1975 | 53608 |
| proceedings: effect of recl mutation on intragenic recombination in escherichia coli k-12. | | 1975 | 54087 |
| proceedings: confirmation of the sequence of the nh2-terminal part of escherichia coli ribosomal protein s21. | | 1975 | 54108 |
| proceedings: the sequence of the cooh-terminal part of escherichia coli ribosomal protein s21. | | 1975 | 54116 |
| [induction of prophage gamma by means of bleomycin treatment]. | the kinetics of induction of lambda prophage with bleomycin a2-cp3, mitomycin c and a combination of these two antibiotics have been studied. bleomycin has been found to cause a rapid induction of prophage in exponentially growing cultures of e. coli k12 (lambda), and the maximal values of including activity are obtained after treatment for 16 minutes with a concentration of 10 mug/ml. the per cent of induction, calculated from the total number of surviving cells, including the phage producing c ... | 1975 | 54184 |
| purification of form ai and aii dna-dependent rna polymerases from rat-liver nucleoli using low-ionic-strength extraction conditions. | recent findings have confirmed the role of form a dna-dependent polymerase activity as that which is responsible for the transcription of the ribosomal rna-coding genes. unfortunately, the form a enzymes have proved to be very labile and difficult to work with, especially under high ionic strength conditions. we have, therefore, investigated a method for the purification of the form ai and aii enzymes from rat liver using mild low-ionic-strength conditions. since preparations from whole nuclei w ... | 1975 | 54256 |
| immunological relationships of bacterial l-asparaginases. | rabbit antisera against l-asparaginase preparations from escherichia coli, erwinia carotovora, citrobacter sp. and chromobacterium violaceum showed on immunoelectrophoresis that only the enzymes from e. coli and citrobacter are immunologically related. purified preparations had to be used to determine the immunological cross-reactions. immunoelectrophoresis at different ph values yielded the zero mobility points of the enzymes. the activity of the er. carotovora preparation was enhanced up to fo ... | 1976 | 54404 |
| letter: escherichia coli k1. | | 1976 | 54718 |
| studies on bacteriophage t7 dna synthesis in vitro. ii. reconstitution of the t7 replication system using purified proteins. | dna synthesis in vitro using intact duplex t7 dna as template is dependent on a novel group of three phage t7-induced proteins: dna-priming protein (activity which complements a cell extract lacking the t7 gene 4-protein), t7 dna polymerase (gene 5-protein plus host factor), and t7 dna-binding protein. the reaction requires, in addition to the four deoxyribonucleoside triphosphates, all four ribonucleoside triphosphates and is inhibited by low concentrations of actinomycin d. evidence is present ... | 1975 | 54868 |
| asymmetric orientation of a phage coat protein in cytoplasmic membrane of escherichia coli. | the coat protein of a filamentous phage (m13) enters the cytoplasmic membrane from two directions: from the outside upon infection and from the cell interior late in the viral life cycle prior to phage assembly and extrusion. binding of 125i-labeled anti-coat protein antibody to spheroplasts or to inverted vesicles was used to assay the orientation of coat protein in the membrane. both parental and newly synthesized coat protein were found to be exposed on the outer surface of the cytoplasmic me ... | 1975 | 54916 |
| mechanism of phosphonoacetate inhibition of herpesvirus-induced dna polymerase. | phosphonoacetate was an effective inhibitor of both the marek's disease herpesvirus- and the herpesvirus of turkey-induced dna polymerase. using the herpesvirus of turkey-induced dna polymerase, phosphonoacetate inhibition studies for the dna polymerization reaction and for the deoxyribonucleoside triphosphate-pyrophosphate exchange reaction were carried out. the results demonstrated that phosphonoacetate inhibited the polymerase by interacting with it at the pyrophosphate binding site to create ... | 1976 | 55273 |
| on the fidelity of dna replication. enzyme activities associated with dna polymerases from rna tumor viruses. | dna polymerase from rna tumor viruses ("reverse transcriptase") has been analyzed for activities which have been associated with other dna polymerases. homogeneous dna polymerase from avian myeoblastosis virus catalyzes pyrophosphate exchange and pyrophosphorolysis. pyrophosphate exchange is dependent on a template and is base-specific. with avian myeloblastosis virus dna polymerase, ribonucleotide templates are more efficient for synthesis while deoxyribonucleotide templates are more effective ... | 1976 | 55414 |
| on the fidelity of dna replication. lack of exodeoxyribonuclease activity and error-correcting function in avian myeloblastosis virus dna polymerase. | homogeneous dna polymerase ("reverse transcriptase") from avian myeoblastosis virus was assayed for exodeoxyribonuclease activity. the substrates were defined template-initiator complexes in which different radioactive nucleotides were present at the 3'-oh termini of the initiator. even when the number of molecules of enzyme was equal to the number of initiator termini there was no significant release of radioactivity with any of the template-initiator combinations tested. under similar conditio ... | 1976 | 55415 |
| immunochemical characterization of the "native" type iii polysaccharide of group b streptococcus. | the type iii polysaccharide of -roup b streptococcus has been isolated and purified by a method that employs washing of intact cells at neutral ph. that the polysaccharide prepared by this procedure is the "native" type iii antigen is suggested by its molecular size in excess of 10(6) daltons, its degradation by acid and heat treatment to a fragment with immunologic characteristics of the classical hcl antigen, and its type-specific serologic activity. the type iii polysaccharide in native form ... | 1976 | 55450 |
| diminished effect of gentamicin under anaerobic or hypercapnic conditions. | the in-vitro activity of gentamicin, judged by m.i.c. determinations, was much reduced when a normal aerobic atmosphere was replaced either by air +4% co2 or by anaerobic conditions. the phenomenon was greatest for staphylococcus aureus, where a decrease in activity of up to 20-fold was found. for escherichia coli, klebsiella aerogenes, enterobacter spp., and proteus spp. the factor of decrease was between 15-fold and 2-5-fold. changes in medium ph, as a result of bacterial growth, can explain t ... | 1976 | 55718 |
| enterotoxin testing of escherichia coli causing epidemic infantile enteritis in the u.k. | three test systems were used to study enterotoxin production by epidemic strains of escherichia coli from cases of infantile enteritis in well-documented outbreaks in the u.k. the tests used were the y1-mouse-adrenal-cell test and the chinese-hamster-ovary-cell (c.h.o.) test for the detection of heat-labile enterotoxin and the infant-mouse test for the detection of heat-stable enterotoxin. all 6 outbreaks had been studied using full serotyping techniques and the results had been published. in ea ... | 1976 | 55904 |
| [immunogenic properties of dna from e. coli and t4 phage, containing 5-bromouracil]. | 5-budr incorporated into e. coli or t4 phage dnas is an immunogenic determinant. immunodominance of 5-budr is determined by the chemical structure of dna molecule into which it is incorporated. in e. coli dna, 5-budr inhibits immunogenic activity of all other bases. one can conclude that in this dna 5-budr is the dominant antigenic determinant. in t4 dna, 5-budr acts as an additional antigenic determinant. anti-5-budr-t4-dna contains antibodies to 5-budr and glucosylated 5-hmc. | 1975 | 55955 |
| bacteriophage mu-1-induced mutation to mutt in escherichia coli. | of approximately 10,000 independent phage mu-1 lysogens, 3 had a mutator phenotype. one (mutation designated mut-49) resembled mutt1 in the frequency and types of mutations induced. mut-49 was mapped between leu and ace and was not separable from the mu prophage. mut-49 was recessive and did not complement mutt1. mut-49, like mutt1, did not increase the reversion of the frameshift mutation lac z (icr48). mut-49 and mutt1 induced the same two classes of trpa78 revertants, indicating that mut-49 i ... | 1976 | 56333 |
| metabolic products of microorganisms. 155. modes of action of rinamycin and derinamycin. | rinamycin interfered with dna-polymerase i of escherichia coli in cell-free systems more effectively than actinomycin c. its inhibitory action could be relieved by increasing the concentration of polymerase. the rinamycin concentrations that caused effective inhibition of the rna-polymerase reaction in vitro were approximately 10 times higher than those required to inhibit the dna-polymerase reaction in vitro. | 1976 | 56926 |
| antigenic determinants of murein lipoprotein and its exposure at the surface of enterobacteriaceae. | murein lipoprotein from the outer membrane of escherichia coli could be fixed to erythrocytes without pretreatment of the erythrocytes. passive hemagglutination or immune hemolysis could thus be used as sensitive assays to determine antibodies against lipoprotein. in rabbit antisera prepared against whole cells of e. coli, salmonella, arizona, and shigella antibodies against lipoprotein were present. the respective titers were lowest in encapsulated smooth strains and highest in rough mutants. a ... | 1976 | 57056 |
| role of a lipopolysaccharide gene for immunogenicity of the enterobacterial common antigen. | it is known that only certain strains of the family of enterobacteriaceae, notably rough (r) mutants with the type r1 or r4 core, evoked antibodies in high titers against the common enterobacterial antigen (ca) after immunization of rabbits with heated cell suspensions. the present investigation deals with genetic and immunochemical aspects of certain r1 and r4 mutants isolated from escherichia coli 08 and various shigella serotypes which, unexpectedly, do not induce ca antibody formation. immun ... | 1976 | 57114 |
| dna synthesis inhibition and the induction of protein x in escherichia coli. | | 1976 | 57241 |
| enhanced antibody responses in active chronic hepatitis: relation to hla-b8 and hla-b12 and porto-systemic shunting. | titres of antibodies to rubella, measles, smooth muscle, nuclei, and escherichia coli were examined in relation to the presence of particular histocompatibility antigens in 57 patients with active chronic hepatitis, 8 of whom were hbsag positive. with the exception of antibodies to e. coli, the hbsag-negative patients with hla-b8 or hla-b12 had higher titres than those with neither, and antibody titres were highest in the 7 cases with both these histocompatibility antigens. in contrast, e. coli ... | 1976 | 57337 |
| letter: serotyping of e. coli. | | 1976 | 57542 |
| effect of bleomycin on deoxyribonucleic acid synthesis in toluene-treated escherichia coli cells. | the antibiotic bleomycin stimulates deoxyribonucleic acid (dna) synthesis in toluene-treated escherichia coli cells. the increase in synthesis is linear with bleomycin concentration. bleomycin-stimulated dna synthesis is independent of replication and dependent on dna polymerase i. replication is spared as the dna polymerase i-dependent dna synthesis increases. bleomycin does not appear to have any effect on purified e. coli dna polymerases i or ii. our results suggest that bleomycin causes nick ... | 1976 | 57740 |
| low-molecular- weight rauscher leukemia virus protein with preferential binding for single-stranded rna and dna. | a sensitive nitrocellulose filter assay that measures the retention of 125i single-stranded calf thymus dna has been used to detect and purify dna-binding proteins that retain a biological function from rauscher murine leukemia virus. by consecutive purification on oligo (dt)- cellulose and deae-bio-gel columns and centrifugation in 10 to 30% glycerol gradients, rna-dependent dna polymerase has been separated from a second virion dna-binding protein. the binding of this protein to dna was strong ... | 1976 | 58075 |
| letter: enteropathogenic e. coli. | | 1976 | 58332 |
| shortening of escherichia coli f-prime f110 by deletion of plasmid-borne chromosomal dna. | | 1975 | 58635 |
| synthesis and the lethality of bleomycin in bacteria. | the bleomycins are antitumor agents composed of various cationic amides of a common inactive bleomycinic acid. at 1 mug/ml at 37 degrees, the naturally occurring spermidine derivative of bleomycin (a5) was far more lethal to escherichia coli than were several other bleomycins tested. an exponential loss of viability was produced for 2 hr in various strains of e. coli growing in a synthetic medium. in the stringent e. coli, strain 15 tau (thymine-arginine-uracil) rel a+ (arginine), withholding th ... | 1976 | 58723 |
| a transmembrane location for the proton-translocating reduced ubiquinone leads to nitrate reductase segment of the respiration chain of escherichia coli. | | 1975 | 58794 |
| [cellular immunity in newborn infants with hyperbilirubinemia]. | in order to identify the possibility of prenatal or perinatal bacterial contact with immunization of the cellular immunity system as underlying cause of the "idiopathic" newborn icterus (without blood group incompatibility) the lymphocyte transformation test with addition of streptolysin o or e. coli antigen was carried out in 68 newborns with a birth weight ranging between 1260 and 4200 g. the sensitization rate identified among the newborns with hyperbilirubinaemia did not differ significantly ... | 1976 | 58819 |
| isolation and characterization of t-even ghost-tolerant mutants of escherichia coli. | mutants of escherichia coli tolerant to the ghosts of t-even phages (t2, t4, and t6) have been isolated from a strain supersensitive to t6 phage. first, t6 supersensitive mutants were isolated from mutagenized e. coli w2252 by replica plating to t6 phage-overlaid agar. one of them, strain nm101, was mutagenized again, grown, and then plated with a high multiplicity of t4 and t6 ghosts. surviving cells were checked for tolerance to ghosts and adsorption of phages. one such ghost-tolerant mutant, ... | 1976 | 58859 |
| lipoprotein from the outer membrane of escherichia coli: purification, paracrystallization, and some properties of its free form. | in the envelope of escherichia coli, is a lipoprotein of molecular weight 7,200 as a major envelope protein. this lipoprotein was previously shown to exist in two different forms in the outer membrane of e. coli: the free form and the boundform, which is covalently linked to the peptidoglycau. the free form of the lipoprotein has been purified and paracrystallized by adding acetone to a sodium dodecyl sulfate solution in the presence of magnesium ion. the paracrystals were needle shaped. an elec ... | 1976 | 58861 |
| importance of full size complementary dna in nucleic acid hybridization. | the size of the dna product synthesized by rna-directed dna polymerase (isolated from avian myeloblastosis virus) was found to be important for complementary dna (cdna)-mrna hybridization reactions. incomplete cdna to rabbit reticulocyte globin mrna formed poor hybrids and presumably lacked sequences needed for hybridization. the size of the cdna synthesized was influenced by the reaction conditions used. the complementary dna product contained 10 s material when synthesis was done at high deoxy ... | 1976 | 58864 |
| an improved quantitative plaque assay for lymphocytes bearing antigen-specific cell receptors. | an improved method for the determination of the number of lymphoid cells bearing antigen-specific receptors is described. the method is based on the use of hapten-coupled bacteriophage (dinitrophenyl-t4) and detection of lytic plaques formed by the action of dnp-t4 on a target e. coli strain. the method is highly specific (up to 90% specific binding) and can be adapted for use with other antigenic determinants chemically attached to an active bacteriophage. | 1976 | 58942 |
| letter: enteropathogenic e. coli. | | 1976 | 59050 |
| letter: serotyping of e. coli. | | 1976 | 59090 |
| letter: transfer of ampicillin resistance from shigella dysenteriae type 1 to escherichia coli. | | 1976 | 59229 |
| the role of polymerase iii in conjugation between e. coli k12 donor and recipient strains carrying dnae ts mutation. | the possible role of dna polimerase iii in conjugation was studied in a series of mutants temperature-sensitive for dna polymerase iii synthesis. the temperature-sensitive dna mutation called dnae 486 (ts) prohibits vegetative dna replication at 41-45 degrees. transfer of episome and chromosome from temperature-sensitive donor, carrying dnae mutation to wild-type recipient strains, revertants and dnae recipients was investigated. in the first two cases the number of lac+ sexductants being even s ... | 1976 | 59532 |
| the mechanism of sensitivity to phleomycin in growing escherichia coli cells. | stationary-phase escherichia coli b cells transferred to new growth medium are initially resistant to net dna breakage by low concentrations of phleomycin, and become sensitive as dna replication commences. from studies with inhibitors of various stages of the dna replication cycle it is evident that it is not dna synthesis itself that is required for induction of dna breakage by phleomycin, but events associated with the initiation of dna replication. termination of replication in the absence o ... | 1976 | 59594 |
| analysis of the diversity of murine antibodies to dextran b1355. i. generation of a larger, pauci-clonal response by a bacterial vaccine. | mice immunized with a combination of dextran b1355 in adjuvant followed by three injections of 2 x 10(9) escherichia coli b organisms produced an average of 14.5 mg/ml of anti-dextran antibodies. it was demonstrated that the stimulating effect of e. coli b was due to antigenic determinants cross-reactive with b1355 and not solely because of adjuvant properties of the organism. the anti-dextran antibodies were distributed among both 7s and 19s components. isoelectric focusing of the 7s antibodies ... | 1976 | 59782 |
| immunochemical studies on bacterial blood group substances. viii. the structure of oligosaccharides from blood group h-active polysaccharide of escherichia coli 2b-v. | blood group h-active polysaccharide has been prepared from "smooth" strain escherichia coli 2b-v by freeman's method, alpha-fucosidase derived from bacillus fluminans caused the liberation of fucose from this polysaccharide, together with concomitant loss of blood group h activity. the results of quantitative microanalysis, borohydride reduction, the morgan-elson reaction and enzymic hydrolysis with betagalactosidase using isolated oligosaccharides obtained by partial acid hydrolysis indicated ... | 1976 | 59831 |
| [study of the structure of o-specific lipopolysaccharide (o-antigen) in escherichia coli 020:k61:h-. i. the oxidation of o-specific lipopolysaccharide by sodium periodate and its reduction by sodium borohydride]. | | 1976 | 59897 |
| rna synthesis in streptomyces antibioticus: in vitro effects of actinomycin and transcriptional inhibitors from 48-h cells. | two forms of dna-dependent rna polymerase have been partially purified (about 100-fold relative to the crude extract) from 48-h old cells of streptomyces antibioticus. the two forms show different mg2+ optima for the incorporation of [3h]ump into rna. substances inhibiting transcription have been isolated by ammonium sulfate precipitation from one of the fractions produced during the polymerase purification. actinomycin can be shown to inhibit rna synthesis catalyzed by the s. antibioticus polym ... | 1976 | 60128 |
| effect of viomycin on dihydrostreptomycin binding to bacterial ribosomes. | viomycin, a peptide antibiotic, reduced the amounts of dihydrostreptomycin bound to ribosomes of myobacterium smegmatis and escherichia coli, although they have different modes of action. the [3h]dihydrostreptomycin binding to ribosomes could not exchanged with streptomycin or dihydrostreptomycin, but not with unrelated antibiotics, namely, kanamycin, neomycin, spectinomycin, capreomycin, tuberactinomycin-n, chloramphenicol and erythromycin. we suggest that there is a significant interaction bet ... | 1976 | 60132 |
| enzymatic in vitro synthesis of globin genes. | full-length, single-stranded rabbit globin cdna, synthesized by amv reverse transcriptase, apparently contains a small double-stranded sequence (hairpin) at the 3' terminus. this cdna can serve as template-primer for e. coli dna polymerase i, which synthesizes a strand complementary to the cdna and covalently bound to it. the loop connecting the two strands can be cut by s1 nuclease. reassociation, hybridization, and restriction endonuclease studies, as well as electrophoretic analyses, indicate ... | 1976 | 60178 |
| immunochemical study of the peptidoglycan of gram-negative bacteria. | the specificity of antibodies directed against the peptidoglycan of gram-negative bacteria was studied. the peptidoglycans of proteus vulgaris, escherichia coli, moraxella glucidolytica, neisseria perflava, give identical precipitin reactions. by means of inhibition studies with various peptidoglycan subunits and synthetic peptides, it was shown that the antibodies are essentially directed against the peptide moiety of the peptidoglycan: l-ala-d-glu (l)-mesoa2pm-(l)-d-ala, that the peptide react ... | 1976 | 60233 |
| dinitrophenol, dicoumarol and pentachlorophenol as inhibitors and parasite substrates in the atp phosphoribosyltransferase reaction. | adenosine-triphosphate phosphoribosyltransferase from escherichia coli is inhibited by dicoumarol and pentachlorophenol in competition with atp. ki was approximately 60 mum for dicoumarol and 50 mum for pentachlorophenol. carbonylcyanide m-chlorphenylhydrazine did not seem to have any kinetic effect. dicoumarol is bound to the extent of 6 sites per enzyme hexamer with a dissociation constant kd of 50 mum. dicoumarol and pentachlorophenol partly prevent the binding of atp and amp to the transfera ... | 1976 | 60234 |
| paromomycin and dihydrostreptomycin binding to escherichia coli ribosomes. | paromomycin binds specifically to a single type of binding site on the 70-s streptomycin-sensitive escherichia coli ribosome. this site is different from that of dihydrostreptomycin since paromomycin binds to streptomycin-resistant ribosomes and sine dihydrostreptomycin does not compete for paromomycin binding. paromomycin binding, unlike dihydrostreptomycin binding, is independent of changes in ribosome concentration but influenced by magnesium ion concentration. moreover, paromomycin does not ... | 1976 | 60235 |
| presence of rfe genes in escherichia coli: their participation in biosynthesis of o antigen and enterobacterial common antigen. | in salmonella, ilv-linked rfe genes participate in the biosynthesis of the enterobacterial common antigen (ca) as well as of certain types of o antigen (serogroups c1 and l). rff genes, probably in the same cluster with rfe, are required for ca synthesis (p.h. mäkelä et al., in preparation). several escherichia coli strains were studied to determine whether they also have rfe-rff genes that are involved in the synthesis of o antigen and ca, or of ca only. in a first approach, e, coli k-12 f-prim ... | 1976 | 60330 |
| purification and properties of two deoxyribonucleases of pseudomonas aeruginosa. | a survey of the major deoxyribonucleases in pseudomonas aeruginosa strain pao was undertaken. two activities predominated in brij-58 lysates of this organism. these have been purified from contaminating nuclease activities, and some of their properties have been elucidated. the first was a nuclease that degraded heat-denatured deoxyribonucleic acid (dna) to mono- and dinucleotides. the activity of this enzyme was confined to single-stranded dna, and 100% of the substrate was hydrolyzed to acid-s ... | 1976 | 60331 |
| effect of orally administered duodenal fluid susceptibility of newborn calves to an escherichia coli challenge. | this study was to determine if duodenal contents inoculated orally could alter symptomatic diarrhea produced by escherichia coli [09:k(a)] in neonatal calves. inoculum was obtained 2 h postprandially from duodenal-cannulated milk-fed calves. thirty holstein bull calves obtained within 3 h of birth were assigned alternately to a 3 x 2 factorial experiment. calves received either 1) no e. coli challenge, 2) challenge at 12 h, or 3) challenge at 24 h each with or without 200 ml duodenal fluid orall ... | 1976 | 60352 |
| studies on the mechanism of enzymatic dna elongation by escherichia coli dna polymerase ii. | | 1976 | 60493 |
| [genetic control of the synthesis of newcastle shigella type-specific vi antigen]. | the authors studied the localization of a determinant of the vi type antigen, sh. newcastle being used in the capacity of donors and e. coli k12 as a recipient. the determinant of the vi type-specific antigen was apparently controlled by the chromosomal gene localized in the region of the histidine operon (on the left from it; 45% of linkage with the his marker). | 1976 | 60854 |
| [protective properties of igm in experiments on animals]. | on a model of intraperitoneal infection of albino mice the authors demonstrated a protective action of the fraction enriched with igm and of gamma-globulin isolated from the normal human blood serum, against e. coli o111. the intensity of the protective action depended on the method, duration of administration of the preparation and also on the infective dose. protective properties of the fraction enriched with igm were more pronounced in comparison with the gamma-globulin preparation. | 1976 | 60856 |
| proceedings: repression in vitro of arginine genes transcription in escherichia coli. | | 1976 | 60928 |
| proceedings: study of the binding of 1-thio-beta-d-galactopyranosides on beta-galactosidase from e. coli. | | 1976 | 60971 |
| amplification and characterization of a beta-globin gene synthesized in vitro. | full-length, double-stranded globin dna was synthesized in vitro starting from rabbit globin mrna. several restriction endonuclease cleavage sites with known recognition sequences were mapped on this dna as a means of assessing the accuracy of in vitro synthesis. by comparing this map with the nucleotide sequences known or predicted from the amino acid sequences of alpha-and beta-chain rabbit hemoglobin, it was possible to show that the synthetic globin dna is a faithful copy of beta-globin mrna ... | 1976 | 61066 |
| a general method for cloning eukaryotic structural gene sequences. | complementary dna, transcribed in vitro from purified rabbit globin messenger rna and made double-stranded, has been inserted into escherichia coli plasmids psc101 and pmb9 by the poly(dt)/poly(da) "tailing" and annealing technique. e. coli transformants given by this dna preparation have been shown to contain globin sequences by the hybridization of globin rna to dna from clones grown and lysed in situ on nitrocellulose filters. an estimate of the amount of inserted globin sequences has been pr ... | 1976 | 61588 |
| immunological cross reactivity of four enzymes involved in the biosynthetic pathway of lysine, methionine and threonine in escherichia coli k12. | in escherichia coli k12 the biosynthetic pathway of lysine, methionine and threonine is characterized by three isofunctional aspartokinases and two homoserine dehydrogenases. a single polypeptide chain carries the threonine-sensitive aspartokinase and homoserine dehydrogenase (ak i-hdh i), and a different polypeptide chain carries the methionine-repressible aspartokinase and homoserine dehydrogenase (ak ii-hdh ii). immuno-adsorbants prepared with rabbit antibodies against ak i-hdh i bind the lys ... | 1976 | 61712 |
| effect of bursa fabricius extracts on antibody production in bursectomized or bursal cell autografted chickens. | restoration and enhancement of immune response against bsa antigen was achieved by 5-day consecutive doses of bf estract from 4-5-week-old chickens, in birds which had been surgically bursectomized or given bf-cell autografts at 17 days of age. a similar 5-day treatment with other tissue extract, i.e. liver, spleen, pancreas or intestine, or with lps of e. coli, in contrast, failed to provide such restoration or enhancement. | 1976 | 61937 |