| inhibition of escherichia coli division by protein x. | we propose that protein x provides the connection between damage to escherichia coli dna and inhibition of septation and cell division. this connection is needed to guarantee that each new bacterium receives a complete dna copy. we present several new experiments here which demonstrate that the degree to which septation is inhibited following damage to dna is correlated with the amount of protein x that is produced. rifampin selectively blocks protein x production. this drug was shown to allow c ... | 1978 | 76627 |
| enzymatic synthesis of dna complementary to mitochondrial mrna via reverse transcription. | the poly(a)-containing mitochondrial mrnas of rat liver were tested for their ability to serve as templates for the dna synthesis by means of reverse transcription in the presence of the oligo(dt) primer and the rna-directed dna-polymerase from avian myeloblastosis virus. the mt-mrna does not support the dna synthesis in the standard conditions sufficient for effective reverse transcription of rabbit globin mrna and of poly(a) in the presence of oligo(dt) primers. after a mild alkaline treatment ... | 1978 | 77007 |
| escherichia coli strains that cause diarrhoea but do not produce heat-labile or heat-stable enterotoxins and are non-invasive. | three enteropathogenic escherichia coli (e.p.e.c.) strains (o127:k63:h6, o128:k67:h2, and o142:k86:h6) isolated from outbreaks of infantile diarrhoea and one strain from the "normal" colonic flora (e. coli hs) of a healthy adult were fed in doses of 10(6), 10(8), and 10(10) organisms in nahco3 to adult volunteers. the strains, which had been stored for 7--9 years, gave negative results in sensitive tests for heat-labile (l.t.) enterotoxin (y-1 adrenal-cell test), heat-stable (s.t.) enterotoxin ( ... | 1978 | 77415 |
| reverse transcription of trna. | the 3' terminus of trna was enzymatically elongated by an oligo(a) tail. a fragment of dna polymerase i (e. coli) was used in the presence of manganese to phase and synthesize a cleavable primer at the oligo(a)-trna template. when the threedimensional structure of oligo(a)-trna is being unfolded under conditions where the primer is still hybridized at the oligo(a) tail, the dna polymerase i fragment transcribes oligo(a)-trna into dna. reverse transcription is slowed down and its fidelity suspend ... | 1978 | 77522 |
| investigations of the uptake of antibiotics influencing membrane function by e. coli cells. | | 1977 | 77626 |
| conservation of the primary structure at the 3' end of 18s rrna from eucaryotic cells. | dna sequencing methods have been used to determine a sequence of about 20 nucleotides at the 3' termini of various 18s (small ribosomal subunit) rna molecules. polyadenylated rrna was first synthesized using the enzyme atp:polynucleotidyl transferase from mainze. then in the presence of an oligonucleotide primer uniquely complementary to the end of each adenylated rrna, a cdna copy was produced using amv reverse transcriptase. in every case, the cdna transcript was of finite size, which we ascri ... | 1978 | 77738 |
| [quantity of compentent cells in a population of escherichia coli treated with ca2+ cations]. | an attempt was made to estimate the number of escherichia coli k-12 cells rendered permeable to antibiotics under ca2+ treatment. the effect of cold factor and ca2+ alone as well as the cell age on the induction of permeability and the energy dependence of the latter were also investigated. about 70-75% and more exponentially growing cells as a result of ca2+ treatment became sensitive to actinomycin, rubomycin and olivomycin. this number was somewhat lower (40-50%) in sationary phase culture. a ... | 1978 | 77802 |
| purification and partial characterization of the b subunit of serratia marcescens tryptophan synthetase. | a trpe mutant of serratia marcescens (e-7) was isolated, and the multimeric enzyme tryptophan synthetase (ec 4.2.1.20) was purified to homogeneity from derepressed cells. the a and b subunits were resolved, and the b subunit was partially characterized and compared with the escherichia coli b subunit as part of a comparative evolution study of the trpb cistron of the trp operon in the enterobacteriaceae. the s. marcescens b subunit is a dimer (beta(2)), and its molecular weight was estimated to ... | 1978 | 77857 |
| binding of trna to reverse transcriptase of rna tumor viruses. | the interaction of trna with the reverse transcriptase (rna-dependent dna polymerase) of mammalian rna viruses, such as moloney murine leukemia virus and simian sarcoma virus, has been studied. whereas the purified reverse transcriptase of mammalian viruses sedimented in glycerol gradients as a globular protein with a molecular weight of 70,000, after interaction with trna the enzyme cosedimented with a protein of 150,000 molecular weight. the twofold increase in molecular weight could be a resu ... | 1978 | 77907 |
| non-enterotoxin-producing, non-invasive enteropathogenic escherichia coli. | | 1978 | 78068 |
| does endotoxin cause both the disease and parasite death in acute malaria and babesiosis? | when mice are infected with either of several species of plasmodium or babesia the amount of escherichia coli lipopolysaccharide (l.p.s.) required to kill them is decreased several hundred fold. the higher their parasitaemia the greater their susceptibility. there is indirect evidence that more l.p.s. than usual is present during infection with these parasites. in a very susceptible host this may be sufficient to produce endotoxin shock. non-antibody mediators able to kill rapidly dividing cells ... | 1978 | 78300 |
| role of escherichia coli colonisation factor antigen in acute diarrhoea. | the role of colonisation factor antigen (c.f.a.) in diarrhoea was studied in volunteers who ingested either e. coli h-10407, which possessed c.f.a., or h-10407-p, which lacked c.f.a. in the first study the dose given was 10(6) c.f.a.+ or c.f.a.- e. coli; in the second study the dose was 10(8) of the same organisms. diarrhoea, with or without other symptoms, occurred only in those who ingested 10(8) c.f.a.+ e. coli. those volunteers taking the c.f.a.- strain shed the test organism in the stool fo ... | 1978 | 78384 |
| [flagellar antigens of e. coli serologically interrlelated to h40, 41 and h41, 42, 43 flagellar antigens of citrobacter. new h-antigeny e. coli i citrobacter]. | the authors confirmed the reference of the test strains h13 (p6c) and h22 (a231a) of the international collection of e. coli to citrobacter; their antigenic formula was established. as shown, strains p6c possessed a variety of the h-antigen which was not described in citrobacter earlier, designated as h41a, 97. three types of flagellar antigens characterized by the presence of an interrelationship with the partial factor h41 of the flagellar citrobacter antigens were revealed in e. coli; the par ... | 1978 | 78607 |
| synthetic disaccharide-protein antigen for production of specific o2 antiserum for immunofluorescence diagnosis of salmonella. | antisera from rabbits immunized with the synthetic disaccharide paratose 1 leads to alpha 3 mannose, representive of salmonella o-antigen 2, covalently linked to bovine serum albumin (bsa), were used in indirect immunofluorescence studies for the identification of salmonella serogroup a (o-antigen 1,2,12) bacteria. among 1311 enteric bacteria tested, 497 were salmonella. the anti-paratose 1 leads to alpha 3 mannose-bsa serum identified correctly all the 63 serogroup a strains tested. no positive ... | 1978 | 78659 |
| complementation in vitro of mutant and wild-type atpase of escherichia coli using isolated subunits. | 1. the inactive atpases of four different mutant strains of escherichia coli have been purified to homogeneity. 2. molecular weights, subunit patterns in sodium dodecylsulfate electrophoresis and immunological properties of mutant and wild-type proteins are identical. the mutant enzymes compete with the wild-type enzyme for the binding sites on the membrane. 3. on freezing and thawing in salt solutions, the atpase is split into subunits ia (alpha, gamma, epsilon), ib (delta; alpha, gamma, epsilo ... | 1978 | 78846 |
| degradation of the polysaccharide component of gonococcal lipopolysaccharide by gonococcal and meningococcal sonic extracts. | an extract made from the supernatant of neisseria gonorrhoeae gc2 strain 1291 degraded the gc2 polysaccharide antigen. chemical analysis of this polysaccharide indicated it contains glucose, galactose, glucosamine, galactosamine, glucosamine-6-phosphate, heptose, 2-keto-3-deoxyotonate, and ethanolamine and is the polysaccharide component of gonococcal lipopolysaccharide. degradation of the polysaccharide by sonic extracts resulted either in complete loss of antigenicity and immunogenicity or in ... | 1978 | 78894 |
| [use of immune reaction with india ink for rapid isolation of enteropathogenic e. coli 0124:k72 (b17)]. | | 1978 | 79022 |
| photochemistry of the bisbenzimidazole dye 33258 hoechst with bromodeoxyuridine and its biological effects on brd urd-substituted escherichia coli. | | 1978 | 79186 |
| lack of inhibition by mouse alpha-foetoprotein (afp) of in vitro induced lymphocyte blastogenesis. | mouse amniotic fluids (maf) were tested for their inhibitory effect on the transformation of lymphocytes by concanavalin a, phytohemagglutinin or lipopolysaccharide of escherichia coli, and on mixed lymphocyte cultures. eight of the thirteen samples tested contained inhibitory activity equal or superior to 50 % of the controls. pure preparations of mousealpha-foetoprotein (afp) were obtained from these or other maf-pools by immunoadsorption and/or by affinity chromatography on oestradiol-sepharo ... | 1978 | 79328 |
| quantitative ultramicro-scale immunoenzymic method for measuring ig antigenic determinants in single cells. | the fluoro ultra micro enzyme linked immuno assay (fumelia) allows one routinely and quantitatively to measure a few thousand antigenic determinants on single cells. highly purified escherichia coli beta-galactosidase has been coupled to specific antibodies. by use of the parafilm microcuvette techniuqe, the activity of the antibody-conjugated beta-galactosidase is assayed with a conventional spectrophotofluorometer. attempts were undertaken to sensitize fumelia even further, so as to be able to ... | 1978 | 79453 |
| enterotoxigenicity of colonising coliform bacteria in tropical sprue and blind-loop syndrome. | the enterotoxigenicity of strains of klebsiella pneumoniae, enterobacter cloacae, and escherichia coli, which represented the predominant coliform species isolated from the jejunum of 12 patients with tropical sprue and 5 with the blind-loop syndrome, was quantitatively assessed in terms of the ability of toxin preparations to induce water secretion as assayed by in-vivo perfusion in the rat jejunum. all 12 patients with sprue harboured 1 or more highly toxigenic strains--14 of the 16 strains is ... | 1978 | 79710 |
| e. coli colonisation factor antigen in diarrhoea. | | 1978 | 79910 |
| bacterial adherence to periurethral epithelial cells in girls prone to urinary-tract infections. | bacterial adherence to epithelial cells from the periurethral region of 48 healthy girls aged over 2 years and of 76 girls with repeated urinary-tract infections was investigated. the infection-prone girls had a significantly higher mean number of adhering bacteria than the healthy controls ( p less than 0.01). this difference was valid irrespective of whether or not the infection-prone girls had urinary-tract infections at the time of investigation. furthermore, statistically significantly high ... | 1978 | 79914 |
| e. coli trnas as inhibitors of viral reverse transcription in vitro. | reverse transcription of 70s amv rna by amv reverse transcriptase has been studied in the presence of e. coli trnas. we have shown that inhibition of dna synthesis occurs and that the trnas bind to the enzyme and not to the 70s rna. the results have implications for the control of reverse transcription in vivo. | 1975 | 79997 |
| use of computerized multidimensional scaling to compare immunoelectron microscopy data with protein near-neighbor information: application to the 30s ribosome from escherichia coli. | a three-dimensional model of the protein arrangement in the escherichia coli 30s ribosome was constructed by using computerized multidimensional scaling of immunoelectron microscope data. this enabled data comparison between the new electron microscope technique and other methods such as crosslinking, chemical protection, affinity labeling, energy transfer, and assembly interactions. the immunoelectron microscopy data are reasonably consistent with those from other sources. reasons for some inco ... | 1978 | 80010 |
| [sensitivity of microorganisms isolated from swine to aqueous and proteinic solutions of gentamycin]. | employing a microbiologic method (in vitro) the activity was investigated of gentamicin dso pharmachim, dissolved in water, in normal swine gamma-globulin, and in normal swine polyglobulin with regard to swine strains of escherichia coli, salmonella choleraesis bordetella bronchiseptica, and pseudomonas aeruginosa as well as mycoplasms. a strong sensitivity was found to exsist in all tested strains (except for the mycoplasms) to gentamycin both in a water and in a protein solution. the in vivo t ... | 1978 | 80055 |
| [reductive methylation : a probe for proteins involved in messenger and transfer ribonucleic acid-binding to the 50 s subunit of escherichia coli ribosomes [proceedings]. | | 1978 | 80192 |
| [degradation of ribosomal rna from escherichia coli by ribonuclease u2 and in vitro transcription of "rna-fragments" into complementary dna]. | under well defined conditions ribosomal rnas purified from escherichia coli can be degraded by ribonuclease u2 giving rise to rna fragments of 60--70 nucleotides. in vitro, these fragments are efficiently transcribed into a complementary dna by dna polymerase rna dependent, partially purified from extracts of e. coli. in vivo, "rna-fragments-u2" inhibit the development of plant tumors. | 1978 | 80289 |
| stimulation of cyclic amp secretion in vero cells by enterotoxins of escherichia coli and vibrio cholerae. | the morphological response of vero cells to escherichia coli heat-labile enterotoxin was similar to that of cholera toxin and was accompanied by increases in the intracellular level of cyclic amp. the effects of both enterotoxins were enhanced by the presence of phosphodiesterase inhibitor and inhibited by heat or specific antisera. accumulation of cyclic amp preceded the morphological response. | 1978 | 80381 |
| new surface-associated heat-labile colonization factor antigen (cfa/ii) produced by enterotoxigenic escherichia coli of serogroups o6 and o8. | enterotoxigenic escherichia coli (etec) belonging to serogroups o6 and o8 do not possess the h-10407-type colonization factor antigen (cfa/i). however, these frequently isolated etec were found to possess a second and distinct heat-labile surface-associated colonization factor antigen, termed cfa/ii. whereas cfa/i mediates mannose-resistant hemagglutination of human group a erythrocytes, cfa/ii does not. cfa/ii mediates mannose-resistant hemagglutination of bovine erythrocytes, and mannose-resis ... | 1978 | 80383 |
| inhibition of reverse transcription of 70s and 35s avian myeloblastosis rnas by nonprimer trna's. | we studied the kinetics of the reverse transcription of 70s and 35s rna of avian myeloblastosis virus in the presence and absence of various trna's. all trna's inhibited synthesis. trna's from escherichia coli and yeast exhibited a noncompetitive type of inhibition, i.e., they bound reversibly and randomly and did not alter the affinity of the viral rna for the polymerase. nonprimer trna's obtained from 70s rna molecules produced a complex pattern of inhibition. the results show that the nonprim ... | 1978 | 80459 |
| antimicrobial resistance and enterotoxin production among isolates of escherichia coli in the far east. | the frequency of association between transferable extrachromosomal d.n.a. (plasmid) mediated antibiotic resistance and enterotoxin productin is unknown. the antimicrobial susceptibility of 176 enterotoxigenic escherichia coli from 57 children and adults in the philippines, korea, taiwan, and indonesia has been examined. 126 isolates (72%) were resistant to one or more antibiotic(s); 77 (44%) were resistant to four or more antibiotics. 43 e. coli which produced both heat-labile and heat-stable to ... | 1978 | 80523 |
| synthesis of an ovalbumin-like protein by escherichia coli k12 harbouring a recombinant plasmid. | a cloned dna transcript of ovalbumin mrna was cut a few nucleotides away from the initiator codon, and fused in phase to the beginning of the escherichia coli beta-galactosidase gene. the hybrid gene has been cloned in e. coli where it produces large amounts of an ovalbumin-like protein. | 1978 | 80751 |
| effect of low concentrations of dihydrostreptomycin on drug resistance in enteric bacteria. | beagle dogs were fed a diet containing 0, 2, or 10 mug of dihydrostreptomycin (dsm) per g of feed. the 2-mug/g level was selected to represent a residue level of the antibiotic. in both treatment groups, medicated feed resulted in a shift from a predominantly streptomycin (sm)-susceptible coliform fecal population to an sm-resistant population. the proportion of resistant organisms was significant (p < 0.01) for both treatment groups. a definitive response did not occur with animals maintained o ... | 1978 | 80973 |
| cannabis, hypochlorhydria, and cholera. | in 90 volunteers participating in a vaccine-development programme consumption of beer more than 3 days a week was linked with high stomach acid output, and smoking of cannabis greater than 2 days a week was linked with low acid output. in 92 volunteers challenged with vibrio cholerae or enterotoxigenic escherichia coli, heavy use of cannabis was associated with more voluminous diarrhoea. cannabis use may be an important factor predisposing to severe diarrhoea. | 1978 | 81411 |
| immune response against the beta-galactosidase enzyme of e. coli at precursor cell level. i. analysis of the secondary repertoire in balb/c mice. | the balb/c secondary response against the beta-galactosidase (beta-gal) enzyme of e. coli was analyzed at the precursor cell level by using the splenic focus technique. our results indicate that in immunized mice, one out of 18 000 b cells is able to recognize beta-gal. among the families of anti-beta-gal monoclonal antibodies, a subset of specific antibodies was detected which is capable of protecting the enzyme from heat denaturation. the frequency of clones making protecting antibodies is 1 o ... | 1978 | 81779 |
| association between streptococcus faecalis urinary infections and graft rejection in kidney transplantation. | in the first month after transplantation 50% of 193 consecutive renal transplant recipients had bacteriuria. the most common organisms isolated were streptococcus faecalis (34), escherichia coli (28), pseudomonas spp. (11), and staphylococcus (9). there was a significant correlation between infection with str. faecalis and graft failure at one, three, and twelve months. this observation suggests that urinary infection with str. faecalis may be associated with graft failure which is probably the ... | 1978 | 82139 |
| pathophysiological effects of vibrio cholerae and enterotoxigenic escherichia coli and their exotoxins on eucaryotic cells. | | 1978 | 82199 |
| [inhibition of opsonization of e. coli by enzyme-treated gammaglobulin (author's transl)]. | the influence of cohn fraction ii, pepsin- and plasmin-treated gammaglobulin on the opsonization of e. coli 0111 was investigated. normal serum at different dilutions, as well as serum of patients with different forms of antibody deficiency syndromes were tested. no effect was observed by pre-incubation of the bacteria in these gammaglobulins if concentrated or 1:10 diluted serum was used for opsonization. in diluted serum cohn fraction ii potentiated and pepsin-treated gammaglobulin competitive ... | 1978 | 82300 |
| effect of enzymatic adenylylation on dihydrostreptomycin accumulation in escherichia coli carrying an r-factor: model explaining aminoglycoside resistance by inactivating mechanisms. | strains of escherichia coli carrying r-factor r71(a), which codes for a streptomycin-spectinomycin adenylyltransferase, have elevated levels of resistance to dihydrostreptomycin (dhs) compared with isogenic r(-) bacteria. dhs accumulated by whole cells and spheroplasts of r(+) bacteria is lower than that observed for r(-) strains, a result of the absence of the second and more rapid of the two energy-dependent phases of dhs uptake seen in susceptible e. coli. a mutant of r(+)e. coli with reduced ... | 1978 | 82422 |
| effects of benzo(a)pyrene adducts of dna synthesis in vitro. | two diol epoxides of benzo(a)pyrene (bp), and benzo(a)pyrene 4,5-oxide, have been used to make adducts in the homopolymers polyribocytidylic acid, (rc); polyriboadenylic acid (ra), polydeoxycytidylic acid (dc) and polydeoxyadenylic acid (da). with appropriate oligomers as primers these modified and unmodified polynucleotides were used as templates for dna synthesis with avian myeloblastosis virus dna polymerase (amv) or e. coli pol i dna polymerase. we have found that: (1) the size of the dna pr ... | 1978 | 82490 |
| mechanisms of clonal abortion tolerogenesis. i. response of immature hapten-specific b lymphocytes. | b lymphocytes with receptors specific for the hapten fluorescein (flu) were prepared from the spleens of mice of various ages. for most experiments, a one-step fractionation procedure based on the adherence of flu-specific cells to flu-gelatin was used. for some experiments, a subset of higher flu-binding capacity was prepared from the flu-gelatin binding population through the use of the fluorescence-activated cell sorter (facs). flu-specific b cells were placed into microculture with either fl ... | 1978 | 82602 |
| lipopolysaccharide interferes with the staining of lipoprotein on polyacrylamide gels. | after electrophoresis of total membrane preparations of escherichia coli b on sodium dodecyl sulfate polyacrylamide gels, and subsequent staining with coomassie brilliant blue, a band corresponding to the braun lipoprotein fails to appear. this is in contrast to similar preparations of e. coli k-12 which do display the lipoprotein upon staining. experiments described below indicate that failure to observe this protein in e. coli b is due to interference in the staining reaction by the lipopolysa ... | 1978 | 83162 |
| k99 surface antigen of escherichia coli: antigenic characterization. | k99 prepared by acid precipitation hemagglutinated guinea pig erythrocytes, whereas k99 prepared by chromatography on diethylaminoethyl-sephadex did not. k99 purified by either procedure hemagglutinated horse erythrocytes. k99 prepared by acid precipitation contained a second antigen not presnet in the k99 prepared by chromatography on diethylaminoethyl-sephadex. this antigen could be detected by immunoprecipitation with some, but not all, sera prepared against k99-positive escherichia coli stra ... | 1978 | 83300 |
| demonstration of shared and unique immunological determinants in enterotoxins from vibrio cholerae and escherichia coli. | immunodiffusion and biological neutralization studies demonstrated that the heat-labile enterotoxin (lt) from escherichia coli has antigenic determinants in common with each of the isolated subunits (a and b) of the enterotoxin (choleragen) from vibrio cholerae. each of the enterotoxins also possesses unique antigenic specificities. monospecific antiserum to lt was prepared by immunization with antigens derived by immune precipitation of e. coli cell-free supernatant with isolated specific antic ... | 1978 | 83301 |
| secretory immunoglobulin a and g antibodies prevent adhesion of escherichia coli to human urinary tract epithelial cells. | the adhesion of escherichia coli to human urinary tract epithelial cells was inhibited by commercial gamma globulin, the total immunoglobulin fraction of human breast milk and urine, as well as the isolated immunoglobulin g and secretory immunoglobulin a fractions of urine from patients with acute pyelonephritis. urinary anti-o6 antibodies reduced the adhesion of several o6 strains. absorption of antibodies to the lipopolysaccharide of the adhering strain markedly decreased the antiadhesive capa ... | 1978 | 83303 |
| immune response in urinary tract infection determined by radioimmunoassay and immunofluorescence: serum antibody levels against infecting bacterium and enterobacteriaceae common antigen. | a solid-phase radioimmunoassay (ria) procedure was compared with the indirect fluorescent antibody (ifa) test in a serological study of 76 female adults with urinary tract infections. relative serum antibody activity was determined against patients' homologous infecting enterobacteria by ria and ifa and against heterologous enterobacterial common antigen (escherichia coli o14) by ria. there was marked correlation between results of the ifa and ria methods using the homologous system; 22 of 51 pa ... | 1978 | 83326 |
| photochemistry and photobiology of 5-azacytidine: effect of repair on photostabilization of escherichia coli. | the photochemical stability of the anomalous nucleic acid base 5-azacytidine (z5cyd) on irradiation at 254 nm is by about one order of magnitude less than that of cytidine (cyd). contrary to the photochemical behaviour, incorporation of z5cyd into the nucleic acids of e. coli strains sr 20 (uvr+ rec+), sr 74 (uvr+ rec-) and sr 22 (uvr- rec+) produced a higher resistance to uv light. only the sr 73 (uvr- rec-) strain was shown to have an increased uv sensitivity. this latter finding is in accord ... | 1978 | 83741 |
| negative staining of freeze-fractured envelopes of escherichia coli k12. | envelope fragments of e. coli k12 have been produced by freeze-fracturing "by hand" and negatively stained after thawing. the outer leaflet of the plasma membrane disintegrated upon thawing whereas the outer leaflet of the outer membrane did not. negative staining revealed the following structural features on the outer membrane fragments: (i) "grooves" 4-6 nm wide, (ii) spherical particles 6-8 nm in diameter, (iii) "black dots" 3-8 nm in diameter. treatment of cells with edta before freeze-fract ... | 1978 | 84079 |
| quantitative aspects of phenyl substituted alcohol and ether bacteriostatic interaction with escherichia coli b/5. | it is well established that compounds of the class phenylalkane alcohols and ethers exert their antimicrobial action on the bacterial envelope--probably on the membrane. however, the overall stoichiometry, the number of molecules bound vs those merely added per cell, and the kinds of equilibria involved (site binding vs equipartitioning) are not clear. this work examines antimicrobial action on e. coli b/5 with eight such compounds. directly determined binding data, plate counting viabilities, r ... | 1977 | 84328 |
| [selective binding of trna by rna dependent dna-polymerase from escherichia coli]. | highly purified rna dependent dna-polymerase was isolated recently from e. coli by romashchenko et al. [8]. the present data demonstrate that total e. coli trna inhibits poly(dt) synthesis on poly (a): oligo (dt) catalyzed by the enzyme when the enzyme:trna ratio is about 1 : 80--100. the inhibition results from the binding of certain trna's by the enzyme. the enzyme trna complex was separated from the unbound trna's by gel-filtration of sephadex g-100. the trna's extracted from the complex are ... | 1978 | 84333 |
| [expression of foreign genes in escherichia coli: problems and perspectives (proceedings)]. | | 1978 | 84606 |
| regulatory mutations insertions, tandem duplications and palindromes in the bipolar argecbh operon of escherichia coli k-12 [proceedings]. | | 1978 | 84607 |
| experiments on duplications and palindromes in escherichia coli [proceedings]. | | 1978 | 84613 |
| bidirectional polarity of is2 elements and the polar effect of an is5 insertion in the argecbh gene cluster of escherichia coli [proceedings]. | | 1978 | 84614 |
| dissection of two arginine operons in escherichia coli by specific endonucleases [proceedings]. | | 1978 | 84615 |
| repressible expression of an escherichia coli cara gene inserted into a colicinogenic factor [proceedings]. | | 1978 | 84616 |
| amino-proximal sequences of the argf and argi ornithine carbamoyltransferases from escherichia coli k-12 [proceedings]. | | 1978 | 84617 |
| transcription polarity of the carab gene cluster of escherichia coli [proceedings]. | | 1978 | 84618 |
| synthesis in vitro of the catalytic subunit of escherichia coli aspartate carbamoyltransferase [proceedings]. | | 1978 | 84634 |
| the enzymatic hydrolysis of the phosphate ester bond in some thionucleotides. | we prepared the 5'- and 3'-o-phosphorothioate esters of the antitumor agent o2 : 2'-anhydro-1-beta-d-arabinosylcytosine. we also included in this study esters of 2'-thio-2'-deoxycytidine, namely, 2'-s-dcyd-2' : 3'-p, 2'-s-dcyd-2'-p, and 2'-s-dcyd-3'-p, along with natural nucleotides. these compounds were subjected to the action of escherichia coli alkaline phosphatase, potato acid phosphatase, and bovine pancreatic ribonuclease a. the data were analyzed by lineweaver-burk plots to obtain km and ... | 1979 | 84687 |
| [affinity alkylation of e. coli rna-dependent dna polymerase with ttp gamma-amidate derivatives]. | ttp gamma-benzylamidates are shown to act as competitive inhibitors of poly(dt) synthesis catalyzed by e. coli rna-dependent dna polymerase. the km value for ttp as well as ki values for the gamma-analogues have been determined. ttp gamma-4-(n-2-chloroethyl-n-methyl-amino)benzylamidate is shown to be an effective affinity reagent for this enzyme. | 1978 | 84690 |
| immunochemical localization of nitrate reductase in escherichia coli [proceedings]. | | 1978 | 84772 |
| expression in escherichia coli of chemically synthesized genes for human insulin. | synthetic genes for human insulin a and b chains were cloned separately in plasmid pbr322. the cloned synthetic genes were then fused to an escherichia coli beta-galactosidase gene to provide efficient transcription and translation and a stable precursor protein. the insulin peptides were cleaved from beta-galactosidase, detected by radioimmunoassay, and purified. complete purification of the a chain and partial purification of the b chain were achieved. these products were mixed, reduced, and r ... | 1979 | 85300 |
| on the serological specificity of the escherichia coli o8 and o9 antigens. | the o8 and o9-specific lipopolysaccharides of escherichia coli lost their serological activity during liberation of the polysaccharide moieties (alpha-mannans) by mild acid hydrolysis, as tested by passive haemagglutination and haemagglutination inhibition. the serological activities and specificities were restored by substitution of the polysaccharides with 1 to 2 stearoyl groups per polysaccharide chain. the mannans obtained by biosynthesis in vitro were serologically active only when bound to ... | 1979 | 85688 |
| replication of plasmid r6k in dna polymerase deficient mutants of escherichia coli. | the plasmid r6k has been introduced into a number of escherichia coli polymerase deficient (pol) mutants. in polcts mutants transferred to the nonpermissive temperature to inactivate polymerase iii, r6k replicates but the replication products have a density in dye-cscl gradients intermediate between supercoiled and linear forms. this aberrant replication requires normal cellular levels of polymerase i since it does not occur in pola polcts mutants. normal r6k replication and maintenance occur in ... | 1978 | 86279 |
| counterimmunoelectrophoresis for rapid identification of blood-culture isolates. | a total of 303 blood cultures that were positive by examination of gram-stained smears were tested immediately by counterimmunoelectrophoresis for detection of bacterial antigens. antigen was detected in all 82 blood cultures containing streptococcus pneumoniae and 11 of 22 with klebsiella pneumoniae, two of two with haemophilus influenzae, and one of one with neisseria meningiditis. false-positive cross-reactions in 265 tests occurred only with pneumococcal omniserum in two cases of nongroupabl ... | 1979 | 86294 |
| detecting enteropathogenic strains of escherichia coli of porcine origin. 2. relationship between o and k antigens and the production of enterotoxin in strains isolated from the piglet after weaning. | the production of enterotoxin by biological tests (yl adrenal cells and the suckling mouse) has been examined in 96 strains of escherichia coli, isolated from sick piglets after weaning. there is a good correlation between the presence of the capsular antigen k88 and that of the thermolabile fraction (lt) of the enterotoxin (69.2 per cent of the enteropathogenic strains studied). however, the presence of the thermostable fraction (st) of the enterotoxin of strains which, according to their serol ... | 1978 | 86320 |
| immunochemical characteristics of shigella sonnei and serotype 6 shigella flexneri lipopolysaccharides and enterobacterial common antigen. | immunochemical studies on shigella sonnei and serotype 6 shigella flexneri 0 antigens (lipopolysaccharides) and enterobacterial common antigen (eca) isolated from shigella sonnei were carried out. oligosaccharide structure of 0-specific chain of serotype 6 shigella fiexneri lipopolysaccharide was defined and beta-l-rhamnosyl-1,3-n-acetyl-d-galactosamin as immunodeterminant of type vi specificity was recognized. the structures of core regions of lipopolysaccharides isolated from r mutants of both ... | 1978 | 86336 |
| the effect of some unspecific stimuli on defence mechanisms in weaned pigs. | the studies were performed to find out whether a prophylactic use of unspecific stimuli affects appreciably the selected biologic indices in weaned pigs. the variables used in the experiment were found to exert a favourable effect on the state of health and growth of pigs but they had no essential influence on the level of immunoglobulins and increase in the titre of antibodies against e. coli (0141, 0149), isolated from pigs kept in the same pigsty. | 1978 | 86338 |
| modification of the rare nucleoside x in escherichia coli trnas with antigenic determining, photolabile, and paramagnetic residues. | | 1979 | 86934 |
| apparent allosterism by avian myeloblastosis virus reverse transcriptase and e. coli dna polymerase i. | a recent report (1) presented evidence for allosterism in reverse transcription by mason-pfizer monkey virus reverse transcriptase and by e. coli dna polymerase i. our experiments also demonstrate these apparent cooperative effects when synthesis is catalyzed by either avian myeloblastosis virus dna polymerase, feline sarcoma virus dna polymerase, or e. coli dna polymerase i (large fragment). we show that the apparent cooperativity depends on the use of oligo(dt)12-18 as primer. however, if the ... | 1979 | 86985 |
| mechanism of conjugation and recombination in bacteria. xx, recombination dna synthesis during mating in escherichia coli k-12. | in crosses of dnaa recipients with hfrh at restrictive temperature a functional recombinant structure and viable recombinants were formed at a nearly normal rate, whereas recombination in crosses with hfrc was markedly inhibited. recombinational dna synthesis, as determined by 3h-thymine incorporation, was found in dnaa merozygotes from hfrh crosses. the recombinational synthesis was completed shortly after the end of mating. the replication of recombinant chromosomes in dnaa lac+ recombinants s ... | 1979 | 87111 |
| spermine hinders post-conjugational recombination in escherichia coli k-12. | treatment of hfr and f- mixture with spermine during the first minutes of mating decreased the number of viable recombinants and inhibited functional recombinant structure formation in the intragenic cross lacz157xlaczs. the treatment applied after 15 minutes of mating was ineffective. the decrease of recombination frequency was not caused by any interference in mating union formation. the efficiency of donor dna transfer in the presence of spermine was increased two-fold. spermine blocked the f ... | 1979 | 87115 |
| mutants of escherichia coli with altered level of beta-n-acetylglucosaminidase activities. | five strains of escherichia coli with reduced level of beta-n-acetylglucosaminidase activity were isolated. the mutations responsible for reduced activity of the enzyme have been localized in one of the strains between 25 and 27 minutes on the genetic map of e. coli. the mutants do not differ morphologically from the original strain. this suggest that beta-n-acetylglucosaminidase is of the secondary importance in the biosynthesis of murein. | 1979 | 87116 |
| effect of different preparation procedures on the ultrastructure of gonococci. | culture samples of neisseria gonorrhoeae and escherichia coli were studied by transmission and electron microscopy to evaluate the effect of different preparation procedures on the pilation of these organisms. unfixed as well as fixed bacteria showed only few, long, filamentous appendages when investigated in ultrathin sections, negatively stained specimens, or critical-point dried preparations. snap-frozen specimens of e. coli showed many short and thin pili after being shadowed with carbon and ... | 1979 | 87241 |
| specific inhibition of the antibody-mediated activation of a defective beta-d-galactosidase by circulating activating epitope-binding molecules. | activation of a defective escherichia coli beta-d-galactosidase by specific activating antibody is inhibited competitively by a molecule with immunoglobulin properties but devoid of activating capacity. this molecule is found in the serum of nonimmunized rabbits and is no longer detectable after beta-d-galactosidase administration, but can be demonstrated in rabbits injected with antigens other than the enzyme. the data show that the inhibitory molecule recognizes and interacts specifically with ... | 1979 | 87481 |
| polyadenylation and reverse transcription of influenza viral rna. | the polyadenylation of fowl plague viral rna and of influenza a/victoria viral rna using e. coli poly (a) polymerase and the subsequent reverse transcription of the polyadenylated species is reported. we have shown that all 8 genome fragments are adenylated and that an average of 25--30 adenylic acid residues per molecule is sufficient for maximal transcription with reverse transcriptase. the cdna product is 95% sensitive to sl-nuclease and hybridisation analysis against viral rna reveals it to ... | 1979 | 88038 |
| a new method for the size estimation of the rna genome segments of influenza virus. | previous estimates of the size of the rna genome segments of influenza virus have been unreliable because of a lack of suitable rna species as size markers. we have attempted to overcome this problem by utilising the ability of amv reverse transcriptase to synthesise full length dna copies of rna molecules in the presence of a suitable primer. by comparing such dna copies of the rna segments of the influenza virus genome with sequenced restriction fragments from the e. coli plasmid pbr322, we ha ... | 1979 | 88039 |
| spread of an r plasmid among antigen types of escherichia coli pathogenic for piglets. | | 1979 | 88059 |
| new maltose blu mutations in escherichia coli k-12. | mutations in the genes pgi, pfka, and ptsg resulted in a maltose blu phenotype in escherichia coli k-12, bringing the number of known blu alleles to six. the blu phenotype, as visualized by staining with iodine vapor, is a convenient mutant isolation technique. | 1979 | 88439 |
| on the occurrence of serum antibodies to bacteroides fragilis and serogroups of e. coli in patients with crohn's disease. | eight strains of bacteroides fragilis, five isolated from patients with crohn's disease and three from healthy individuals, and according to biochemical tests belonging to four subspecies, were subjected to a serologic examination with tube agglutination and passive hemagglutination (ha) tests using hyperimmune rabbit antisera. a close antigenic relationship was demonstrated between two of the strains and minor relationships between three other strains. cross absorption experiments showed that t ... | 1979 | 88760 |
| enzymic polyadenylation of 5s ribosomal ribonucleic acid and synthesis of a complementary deoxyribonucleic acid. | the 5s ribosomal rna has been isolated, pure and intact, from rat liver (5 mg of 5s rna from 150g of liver). the 5s rna serves as a primer for calf thymus poly(a) polymerase with 20% of the efficiency of (ap)3a. bacterial 5s rna and transfer rna also serve as primers; rat liver 18s and 28s ribosomal rnas support poly(a) synthesis poorly. neither the 5s rna primer nor the appended poly(a) tract is nicked or degraded by poly(a) polymerase, and initiation of poly(a) tracts on 5s rna primers continu ... | 1979 | 88957 |
| isolation and characterization of homogeneous heat-labile enterotoxins with high specific activity from escherichia coli cultures. | the heat-labile enterotoxin (lt) has been isolated in homogeneous form with high specific activity from three sources: cell-free supernatant, nacl extract, and whole-cell lysates of an enterotoxigenic escherichia coli strain. in vitro immunological assays were used in lieu of tedious and highly variable bioassays to recognize fractions with activity. this revealed that the major portion of the lt remained adherent to columns containing agarose, from which it could be eluted quantitatively in pra ... | 1979 | 89088 |
| translocation and assembly of outer membrance proteins of escherichia coli. selective accumulation of precursors and novel assembly intermediates caused by phenethyl alcohol. | | 1979 | 89196 |
| mechanism of conjugation. iii. properties of an hfr dna 11ts mutant of escherichia coli k-12. | | 1979 | 89795 |
| effect of spermine on number of crossing-over events in post-conjugational recombination in escherichia coli k-12. | | 1979 | 89796 |
| mutant analysis of glyceraldehyde 3-phosphate dehydrogenase in escherichia coli. | nad(+)-specific glyceraldehyde 3-phosphate dehydrogenase (ec 1.2.1.12) from escherichia coli was purified to homogeneity by a relatively simple procedure involving affinity chromatography on agarose-hexane-nad(+) and repeated crystallization. rabbit antiserum directed against this protein produced one precipitin line in double-diffusion studies against the pure enzyme, and two lines against crude extracts of wild-type e. coli strains. both precipitin lines represent the interaction of antibody w ... | 1979 | 89843 |
| structure and serological specificity of the k13-antigenic polysaccharide (k13 antigen) of urinary tract-infective escherichia coli. | the primary structure of the k13-antigenic polysaccharide (k13 antigen) of escherichia coli o6:k13:h1 was elucidated by composition, periodate oxidation, smith degradation, and methylation analysis. the polysaccharide consists of a repeating sequence of 3-linked ribofuranose and 7-linked 3-deoxymannooctulosonic acid (kdo). about 50% of the kdo residues are o-acetylated at position 4 or 5. measurement of the optical rotary dispersion indicated that in aqueous solution the k13 polysaccharide assum ... | 1979 | 90016 |
| specificity of antipyrogenic immunity. | the specificity of antipyrogenic immunity as well as the structural differences of the enterobacteria responsible for pyrogenicity have been studied. strains s. minnesota re 595 and s. typhimurium sl 1102 as well as glycolipids obtained from them, further e. coli 083 and e. coli f 576 as well as the lps extracted from them were used in the experiments. in conformity with the results of chemical analysis it was found that the method reflected exactly the antigenicity of the receptors responsible ... | 1978 | 90447 |
| reverse transcriptase pauses at n2-methylguanine during in vitro transcription of escherichia coli 16s ribosomal rna. | a restriction fragment strand complementary to a sequence near the 3' end of escherichia coli 16s rrna has been used to prime reverse transcriptase (avian myeloblastosis virus rna-directed dna nucleotidyltransferase; deoxynucleosidetriphosphate:dna deoxynucleotidyltransferase, ec 2.7.7.7). in addition to transcripts that were extended to the 5' end of the rna, two major transcription intermediates were observed. these discrete-sized cdna intermediates are the result of a kinetic barrier imposed ... | 1979 | 91169 |
| the effect of 5-azacytidine on e. coli dna methylase. | | 1979 | 91371 |
| immunological specificity of natural opsonins and their role in the cross-reactivity between staphylococcus aureus mardi and escherichia coli 101. | the immunochemical specificity of the observed cross-reactivity between escherichia coli strain 101 and staphylococcus aureus strain mardi was examined. the cross-reactivity was shown to be dependent upon mucopeptide antibodies which are present in normal and immune sera. although both organisms contained surface antigens with immunodominant glucuronic acid residues, in vitro phagocytosis studies indicated that antibodies directed against these antigens were not significantly involved in the ops ... | 1979 | 91583 |
| trace polypeptides in cellular extracts and human body fluids detected by two-dimensional electrophoresis and a highly sensitive silver stain. | development of a highly sensitive silver stain permits the characterization of trace cellular and body fluid proteins separated by the two-dimensional electrophoresis technique of o'farrell. many of the proteins detected by the silver stain in urine, spinal fluid, amniotic fluid, and cells were undetected with the widely used coomassie blue stain. trace polypeptides observed in escherichia coli cell lysates with this silver stain could be detected previously only by growth in radioactive precurs ... | 1979 | 92027 |
| aggregation deficient escherichia coli k-12 female mutants with altered lipopolysaccharide. | two f- mutants deficient in conjugation with f-donors have been characterized. they map at about 83 minut position, show resistance to t3 and t7 bacteriophages, and form mating aggregates in the liquid medium with lowered efficiency. mutants have no detectable alterations in their outer membrane protein composition. | 1979 | 92169 |
| new types of escherichia coli k-12 facultative recombination deficient mutants resistant to ultraviolet. | numerous facultative temperature sensitive recombination deficient mutants of escherichia coli k-12 strain 108 were isolated after mutagenization with nitrosoguanidine. the majority of the mutants were resistant to uv irradiation. three mutants, kbp72, kbp169 and kbp610, with marked recombination deificiency (300 to 15,000 times) at 42 degrees c, were uv resistant; their sensitivity to mitomycin c was altered only slightly or not at all. mutation kbp72 was co-transduced with ilv (83 unit on e. c ... | 1979 | 92170 |
| transfer of rp4 and r68.45 factors to rhizobium. | two r factor were introduced by conjugation into rhizobium trifolii and rhizobium meliloti strains at a frequency of 10(-5) to 10(-6). plasmids rp4 from escherichia coli j53 and r68.45 from pseudomonas aeruginosa pao.25 were maintained stably in rhizobium hosts and could be retransferred to other rhizobium recipients. some of the transconjugants were able to mobilize chromosome and transfer his or met genes in intra-, and interspecies matings. | 1979 | 92171 |
| the o antigenic relationships of kloeckera africana, salmonella aberdeen and escherichia coli o75. | the immune sera for salmonella aberdeen (o11) and escherichia coli (o75) agglutinated kloeckera africana strain. the immune serum for k. africana agglutinated s. aberdeen (o11) and e. coli (o75) strains. absorption and agglutination cross-tests demonstrated common antigenic factor(s) in the tested yeast and salmonella o11 and e. coli o75 antigens. | 1979 | 92211 |
| the illicit permeation of n-delta-phosphonoacetyl-l-ornithine under the form of a tripeptide. selective inhibition in vivo of escherichia coli l-ornithine carbamoyltransferase [proceedings]. | | 1979 | 92272 |
| an examination of the o and k specificity involved in the antibody-induced loss of the k88 plasmid from porcine enteropathogenic strains of escherichia coli. | the heat-labile k88 antigen, a virulence determinant coded for by a transmissible plasmid, was eliminated from enteropathogenic strains of escherichia coli by passage through media containing antibodies to the heat stable antigens of an abbotstown (o149:k91,k88ac) strain. the plasmid-curing activity of o149 antisera was not o-antigen specific as o149, o45, o8 and o138 strains of e. coli could be 'cured' of their k88 plasmids by this technique. the curing activity was differentiated from the o-an ... | 1979 | 92455 |