Escherichia coli

Eur J Biochem, 1976 Dec, 71(1), 185 - 92
Degradation of abnormal proteins in Escherichia coli . Differential proteolysis in vitro of E . coli alkaline phosphatase cyanogen-bromide-cleavage products; Kemshead JT et al.; Escherichia coli alkaline phosphatase has been purified and modified by either carboxymethylation or treatment with cyanogen bromide (CNBr) . Only the CNBr-treated protein was degradable in an E . coli cell extract . Separation of the CNBr cleavage products by gel filtration in non-denaturing conditions gave rise to a number of oligomeric complexes, of which only those of molecular weight less than approximately 29000 were degradable in E . coli cell-free extracts . Carboxymethylation of the non-degradable complexes (greater than 29000 molecular weight) resulted in the formation of some complexes of less than 29000 molecular weight: such newly formed complexes were degradable by E . coli cell-free extracts . It is suggested that E . coli cell-free extracts may contain a protease/peptidase system which is active against peptide complexes below 29000 molecular weight, but inactive against peptide oligomers of greater molecular weight.

Cell, 1976 Dec, 9(4 Pt 1), 495 - 502
Identification and location of the histone H2A and H3 genes by sequence analysis of sea urchin (S . purpuratus) DNA cloned in E . coli; Sures I et al.; A 2000 base pair (bp) DNA fragment can be excised from sea urchin (S . purpuratus) histone gene repeat units with restriction endonuclease Eco R1 . This DNA, which has been cloned in a bacterial plasmid, is known to encompass two of the five histone genes . The fragment has a single endonuclease Hind III cleavage site in one of the genes and a Hae III cleavage site in the other gene . We now report the nucleotide sequences of 62 bp adjacent to the Hind III site and 42 bp adjacent to the Hae III cleavage site . The results identify the cloned DNA as histone genes, show that it codes for histone proteins H2A and H3, and locate and orient H2A and H3 genes with respect to restriction endonuclease sites in the repeat unit.

Nucleic Acids Res, 1976 Dec, 3(12), 3383 - 96
The kinetics of bisulphite modification of reactive residues in E . coli tRNA2Phe; Lowdon M et al.; E coli tRNA2Phe was modified at 25 degrees C with 3M sodium bisulphite, pH6.0, for periods of up to 48 hours, Three cytadinine residues, at position 17, 74 and 75 from the 5' end were each deaminated to uridine . The 2-methylthio-N6-isopentenyl adenosine at position 37 formed a 1:1 bi-sulphite addition product which was stable to alkaii . No other residues were permanently modified . The rate of modification of each residue was first order with respect to remaining unmodified nucleotide, the time of half reaction, t1/2, being different for each residue . C17 reaction reacted at twice the rate of cytidine in PolyC, indicating that it occupied a very exposed position in the tRNA.

J Trauma, 1976 Dec, 16(12), 968 - 73
Effects of indomethacin and nicotinic acid on E . coli endotoxin shock in anesthetized dogs; Hilton JG et al.; The effects of single and multiple doses of indomethacin and multiple doses of nicotinic acid upon Escherichia coli endotoxin shock were studied in mongrel dogs anesthetized with sodium pentobarbital . Survival, cardiac output, plasma volume loss, and mean arterial pressure were measured . Untreated animals did not survive the procedure; animals treated with either multiple doses of indomethacin or nicotinic acid did survive for 5 hours after endotoxin . Plasma volume losses of indomethacin and nicotinic acid treated animals were substantially less (p less than 0.05) than in untreated animals . Arterialpressures of indomethacin-treated animals were greater than that of either nicotinic acid treated or untreated animals . No differences in cardiac output were noted in surviving animals.

Br J Pharmacol, 1976 Dec, 58(4), 547 - 51
The effect oa a new anti-inflammatory drug, flurbiprofen, on the respiratory, haemodynamic and metabolic responses to E . coli endotoxin shock in the cat; Parratt JR et al.; 1 The intravenous administration of E . coli endotoxin (2.0 mg/kg) in cats anaesthetized with sodium pentobarbitone resulted in immediate pulmonary hypertension and reductions in lung compliance and systemic arterial PO2 . These effects were abolished, or greatly reduced, by the prior intravenous administration of flurbiprofen in doses (100 and 250 mug/kg and 1.0 mg/kg) which were devoid of cardiovascular or metabolic effects . Flurbiprofen is thus the most active antipyretic-analgesic drug so far examined in this experiment model . 2 Production of lactate, characteristic of the severe, secondary endotoxin shock phase, was delayed only by the highest dose of flubiprofen; hypotension, hypoglycaemia and the reduction in cardiac output which occurs during this phase, were unaffected . 3 These findings are discussed with reference to the treatment of the (shocked lung" syndrome of human septicaemia.

J Pediatr, 1976 Dec, 89(6), 892 - 7
Interaction of E . coli strains with human serum: lack of relationship to K1 antigen; Bjorksten B et al.; Twenty-eight strains of E . coli isolated from infants were compared with respect to opsonic requirements, sensitivity to serum, and ability to activate serum chemotactic factors . Six of the strains were isolated from stools of healthy newborn infants; 22 were isolated from the cerebrospinal fluid or blood of infants with meningitis and/or septicemia . Eighteen of the strains had K1 polysaccharide antigen . Fourteen of the strains (seven with K1 antigen) activated complement via the alternative pathway and all of these strains were well opsonized in 4% pooled human serum . A higher concentration of serum was necessary to opsonize 12 of the 14 strains that did not activate the alternative pathway . A wide variation was also found in opsonic requirements of E . coli strains isolated from healthy and sick infants . There was no relationship of the K1 antigen to opsonic requirements, to capacity to activate complement via the alternative pathway, to generation of chemotactic factors, or to sensitivity to serum cidal activity . Therefore, the association of E . coli with K1 antigen and neonatal meningitis did not appear to be related to these bacteria-serum interactions.

Biochimie, 1976 Nov 13, 58(9), 1123 - 8
The shikimate pathway . III . 3-dehydroquinate synthetase of E . coli . Mechanistic studies by kinetic isotope effect; Le Marechal P et al.; The conversion of 3-deoxy D-arabino heptulosonate 7-phosphate to 3-dehydroquinate by the 3-dehydroquinate synthetase from E . coli is characterized by a low but significant kinetic isotope effect for tritium carried in position-5 of DAHP, while no isotope effect was detectable for tritium in position-4 . This effect was observed at different pH nad is interpreted as a result of theintermediary of a 5-ketonic form of the substrate, formed in a preliminary non limiting step during the enzymic cyclization reaction . A tentative scheme for the 3-DHQ synthetase reaction is proposed involving five steps: oxidation by NAD+ in position-5, phsophate elimination after enolization, reduction with precedently formed NADH and cyclization by attack of the 2-carbonyl by the C-7 methylene group.

Mol Biol (Mosk), 1976 Nov-Dec, 10(6), 1403 - 12
{Conformational transitions in tRNA fMet from E . coli induced by monovalent and divalent ions}; Surovaia AN et al.; Conformational transitions in tRNAfMet E . coli the initiator tRNA in bacterial systems and in some other individual tRNAs have been studied as a function of monovalent and divalent ion concentrations . By measuring the extent of energy transfer between dye molecules adsorbed on tRNAs and by study of adsorption isotherms of dyes on tRNAs conclusion has been drawn about the similarity of conformational state of all tRNAs studied at low ionic strength (mu 0.01) . A conformational change in tRNA, produced by an addition of Mg2+ and Na+ ions results in more than two fold decrease of the strong binding sites for dyes . A marked difference in the adsorption properties of tRNAfMet in comparison with other investigated tRNAs were found . The tRNAfMet was the only tRNA species that did not form the strong type of complexes with dyes at high ionic strength

Mol Biol (Mosk), 1976 Nov-Dec, 10(6), 1394 - 402
{Donor site of E . coli ribosomal peptidyltransferase}; Kotusov VV et al.; The mechanism of 5'-cytidilic acid stimulation of the reaction between 2'(3')-O-formylmethionine ester of 5'-adenylic acid and phenylalanyl-tRNA catalyzed by E . coli ribosomes has been studied . It has been shown that cytidilic acid binds to the donor site of the peptidyltransferase in the area which is usually occupied by the second nucleotide residue of the peptidyl-tRNA 3'-end . After the binding cytidilic acid stimulates effectively the donor activity of formylmethionine ester of adenylic acid . A number of compounds have been tested as possible stimulants . Both the chemical nature of stimulant and its conformation are important for the stimulating action . A hypothetic scheme is suggested explaining possible causative factors of peptidyl-tRNA translocation from the acceptor site to the donor site after peptide bond formation.

Mol Biol (Mosk), 1976 Nov-Dec, 10(6), 1369 - 77
{Protein content of E . coli membrane under conditions of repressed and derepressed biosynthesis of alkaline phosphatase}; Severin AI et al.; Protein content of membranes in wild type strains of E . coli K12 and K10 and in mutants defective in alkaline phosphatase regulator genes: E . coli C85 (R1-R2+p+) and E . coli C4(R1+R2-P+) under the conditions of repression and derepression of this enzyme was studied . Correlation between the content in membranes of minor component with the molecular weight 30,700 and the state of the regulatory system of alkaline phosphatase biosynthesis was shown . This protein was absent in the membranes of the repressed cells of wild type strains and in the membranes of nonrepressible (constitutive) mutant E . coli C4 . Probably the protein with molecular weight 30,700 is a product of the regulatory gene R2 and its binding with the membrane determines its regulatory function.

Mol Biol (Mosk), 1976 Nov-Dec, 10(6), 1231 - 7
{Separation of the enzyme catalyzing polymerization of deoxyribonucleoside diphosphates from preparations of E . coli DNA-polymerase I}; Nazarenko IA et al.; The enzyme which catalyses template independent synthesis of polydeoxynucleotides from deoxynucleoside diphosphates was separated from E . coli DNA polymerase I by DEAE-cellulose chromatography followed by ultrafiltration through the M-50 Amicon filter . The ultrafiltration data indicate that the molecular weight of the enzyme is not higher than 50,000 . The enzyme is not able to use deoxynucleoside triphosphates, ribonucleoside di- or triphosphates as substrates for the polymerization . The reaction of template independent polymerization proceeds with a lag period varying from 2 to 20 hours (for different preparations of enzyme) and is activated by Mg2+ (the optimal concentration 1-2 . 10(-3) M) . The pH optimum of the reaction is at 8.5 . The optimal concentration of deoxyribonucleoside diphosphates is 10(-3) M, and its increase strongly inhibits polymerization . The enzyme was supposed to be called deoxynucleoside diphosphate: olygonucleotide deoxynucleotidyltransferase (catalyzing polymerization without template) . The presence of the enzyme in the preparations of E . coli DNA-polymerase I can explain the ability of the latter to catalyze the untemplated synthesis of poly dG : poly dC.

Mol Biol Rep, 1976 Nov, 3(2), 151 - 6
Catalysis of the peptide bond formation by 50 S subunits of E . coli ribosomes with N-(formyl) methionine ester of adenylic acid as peptide donor; Kotusov VV et al.; 50 S subunits of E . coli ribosomes catalyze the reaction of the 2'(3')-N-(formyl) methionine ester of adenosine 5'-phosphate and Phe-tRNA resulting in peptide bond synthesis . Cytidine 5'-phosphate stimulates this process on 50 S ribosomal subunits as well as on intact ribosomes . The obtained data show that the areas of the peptidyltransferase donor site which binds the 3'-terminal fragment of peptidyl-tRNA possess completely formed structures on 50 S ribosomal subunits.

Mol Biol Rep, 1976 Nov, 3(2), 105 - 11
Further evidence for the participation of proteins S 3, S 14 and S 19 in tRNA binding to E . coli 30 S subunits; Shimizu M et al.; Previous studies have shown that iodination of 30 S subunits causes inactivation for both enzymatic fMet-tRNA and non-enzymatic phe-tRNA binding activities . This inactivation was shown to be due to the modification of three to five ribosomal proteins {1} . In this report the role of these proteins in tRNA binding activity has been further studied . Purified ribosomal proteins, isolated from modified subunits, are re-assembled into otherwise unmodified 30 S ribosomes and assayed for tRNA binding capacity . The presence of modified S 3, S 14 and S 19 (S 15) in the reconstituted particle results in substantial reduction of both fMet-tRNA and phe-tRNA binding activities . This reduction in tRNA binding activity does not appear to be due to an assembly defect.

Nucleic Acids Res, 1976 Nov, 3(11), 3123 - 31
Secondary structure of nucleic acids in the folded chromosome from E . coli; Baase WA et al.; The circular dichroism of membrane-free folded chromosomes from E . coli was measured and analyzed . The spectrum can be explained as a simple linear combination of the individual spectra of E . coli RNA, and E . Coli DNA in the B form . No contribution from A form or C form DNA was detected . There was evidently some real variation in the ratio of the two nucleic acids from preparation to preparation, but the average value was 24% RNA and 76% DNA . No significant light scattering was observed and the analyses indicated no contribution to the circular dichroism from scattering artifacts . Apparently, combining DNA, RNA, and protein into membrane-free folded chromosomes does not change the secondary structure of the DNA or RNA from that found for the free nucleic acid in the same solvent system.

Mutat Res, 1976 Nov, 37(2-3), 163 - 72
Lethal effects of pyrimidine dimers induced at 365 nm in strains of E . coli differing in repair capability; Webb RB et al.; Photoreactivation (PR) after 365-nm inactivation was measured in four strains of Escherichia coli differing in repair capability . Photoreactivation was observed in the recA strains K12 AB2480 and K12 AB2463 indicating a significant role of pyrimidine dimers in the lethal action of 365-nm radiation in these strains . Significant PR was not observed in the uvrA strain, K12 AB1886, or in the repair proficient strain, K12 AB1157, after 365-nm inactivation . Biological evidence indicated that stationary phase cells had not lost the capacity for photo-enzymatic repair after fluences of 365-nm radiation of 2 X 10(6) J/m-2 or less . It is proposed that pyrimidine dimers, although induced, are not significant 365-nm lethal lesions in uvrA and wild-type strains because of their efficient dark repair.

Chem Biol Interact, 1976 Nov, 15(3), 219 - 31
Evaluation of a DNA polymerase-deficient mutant of E . coli for the rapid detection of carcinogens; Fluck ER et al.; Differential growth inhibition of two E . coli cultures was evaluated as a rapid screening technique for chemical carcinogens . Of the carcinogens tested, only "direct acting" carcinogens produced positive results . Furthermore, this test is not a quantitative assay in that neither was a dose--response relationship seen nor did potent carcinogens necessarily show a greater response than weaker carcinogens.

Mol Gen Genet, 1976 Oct 18, 148(2), 125 - 30
Induction kinetics of mutagenic DNA repair activity in E . coli following ultraviolet irradiation; Defais M et al.; Ultraviolet mutagenesis of phage gamma is produced by host functions which are inducible by ultraviolet irradiation of the host cell . Induction kinetics and the half life of the inducible mutagenic DNA repair (SOS-repair) in E.coli have been determined using phage gamma assays . At 37 degrees C, both mutagenic and repair activities are maximal approximately 30 min following irradiation and decay with a half life of approximately 30 min . The presence of 100 mug/ml chloramphenicol during the first 40 min after irradiation completely abolishes induction of repair and mutagenesis . The ultraviolet induction pattern of SOS repair very much resembles that of gamma prophage in lysogenic induction (Monk and Kinross, 1975).

Biull Eksp Biol Med, 1976 Oct, 82(10), 1237 - 9
{Isolation of the thermolabile E . coli enterotoxin and the study of its biological properties}; Volunskii MIa et al.; Enterotoxin was obtained from the culture of E . coli O15 by salt precipitation and gel-chromatography . The toxic activity of the preparation increased during the isolation and purification: 60-fold according to the results of the method of ligated rabbit intestinal segment and 66-100-fold according to the skin test . The "plateau" and the second fraction obtained as a result of gel-chromatography were inactive according to the results of the method of ligated intestinal segment, but possessed PF-activity in the skin test . Two suppositions are put forward: 1) possibly the factor of vascular permeability and the diarrheal factor were two different substances ((molecules), or 2) the skin test was more sensitive for determination of the toxicity than the method of the ligated segment of rabbit intestine.

C R Acad Sci Hebd Seances Acad Sci D, 1976 Sep 27, 283(6), 679 - 81
{Brownian motion of biological macromolecules studied by triplet-triplet dichroism: application to the 70S ribosome of E . coli}; Amand B et al.; The dichroism of the long-lived triplet-triplet absorption of covalent labels has been used for measuring the brownian rotational relaxation time of giant macromolecules in the microsecond time range . Using this method, a radius of 147 A has been found for E . coli 70 S ribosomes in solution.

Mol Gen Genet, 1976 Sep 23, 147(3), 291 - 7
Phage T4 infection restricts rRNA synthesis by E . coli RNA polymerase; Baralle FE et al.; RNA polymerase from T4 infected cells supplemented with E . coli sigma polypeptide has a lower affinity for rRNA promoters than RNA polymerase from uninfected cells . The pattern of transcription by the phage modified polymerase is qualitatively similar to that of the vegetative polymerase in the presence of ppGpp . We suggest that E . coli polymerase holoenzyme normally exists in at least two conformational states, one with a high affinity for rRNA promoters and another with a low affinity, and that T4 infection stabilises the low affinity form.

Nucleic Acids Res, 1976 Sep, 3(9), 2171 - 82
Unfolding of E . coli ribosomes: evidence for pre-existing breaks in the large subunit; Scafati AR et al.; An investigation has been made on structure modifications of E . coli ribosomes following EDTA treatment . When completely deprived of magnesium, the small subunit sediments at 16S while the large one, in the same conditions, shows two components at 17S and 21S . Unfolding causes in both subunits an increase in radius of gyration without substantial change in molecular weight, as shown by light scattering measurements . The occurence of the slower 17S component besides the 21S one has to be connected with a fraction of the large subunit population which presents nucleolytic breaks in its RNA chain . These breaks do not cause fragmentation of the unfolded subunit but lead to a more open configuration sedimenting at lower velocity.

Mol Biol Rep, 1976 Sep, 3(1), 39 - 46
Loosening and unfolding of E . coli 50 S ribosomal subunits: dependence on magnesium content and temperature; Ivanov DA et al.; Reversible change of 50 S ribosomal subunits to 40 S particles takes place in cold buffered 0.5 M NH4Cl solutions either containing Mg++ (up to 0.1 M), or free from Mg++ and even supplemented with EDTA (1 mM) . The 40 S particles were stable only within a definite temperature range . Heating of the samples caused completely irreversible unfolding of the 40 S particles . This "melting" appeared to be co-operative and took place within a very narrow range of temperature, which for samples containing Mg++ was a linear function of the log of Mg++ concentration . The results suggest that two types of bonds maintained the compact structure of the ribosomal subunits: ionic bonds involving Mg++ and heat-labile weak interactions between ribosomal components.

Cell, 1976 Sep, 9(1), 91 - 9
A colony bank containing synthetic Col El hybrid plasmids representative of the entire E . coli genome; Clarke L et al.; Using the poly(dA-dT) "connector" method (Lobbanand Kaiser, 1973), a population of annealed hybrid circular DNAs was constructed in vitro; each hybrid DNA circle contained one molecule of poly(dT)-tailed Col El-DNA (LRI) annealed to any one of a collection of poly(dA)-tailed linear DNA fragments, produced originally by shearing total E . coli DNA to an average size of 8.5 x 10(6) daltons . This annealed DNA preparation (12 mug) was used to transform an F+ recA E . coli strain (JA200), selecting transformants by their resistance to colicin El . A collection or "bank" pf pver 2000 colicin El-resistant clones was thereby obtained, 70% of which were shown to contain hybrid Col El DNA (E . coli) plasmids . This colony bank is large enough to include hybrid plasmids representative of the entire E . coli genome . Individual plasmids have been readily identified by replica mating the collection onto plates seeded with cultures of various F- auxotrophic recipients, selecting for complementation of the auxotrophic markers by F-mediated transfer of hybrid plasmids to the F- recipients . In this manner, over 80 hybrid Col El-DNA (E . coli), plasmid-bearing clones have been identified in the colony bank, and about 40 known E . coli genes have been tentatively assigned to these various plasmids . The hybrid plasmids are transferred efficiently from F+ donors to appropriate F- recipients . The use of this method to establish similar colony banks in E . coli containing hybrid plasmids representative of various simple eucaryotic genomes is discussed.

Cell, 1976 Sep, 9(1), 147 - 61
Histone genes of the sea urchin (S . purpuratus) cloned in E coli: order, polarity, and strandedness of the five histone-coding and spacer regions; Cohn RH et al.; Sea urchin (S . purpuratus) histone DNA of constructed plasmid chimeras cloned in E . coli was cleaved with the restriction endonucleases Eco RI, Hind III, Sal I . Bam I, and Hha I . The resulting fragments were ordered and isolated directly from agarose gels or cloned into other plasmids . Each fragment hybridized to one or another of the five histone mRNAs and elucidated the order of the histone genes in each of the cloned fragments . Some DNA did not hybridize to histone mRNAs and was identified as spacer DNA located between coding regions . Total sea urchin DNA was cleaved with restriction endonucleases, fractionated on agarose gels, and hybridized to histone mRNAs or histone DNA . The results revealed the order of the five histone genes in the histone gene repeat unit and demonstrate that the histone spacer DNA have little sequence homology to other genes . ExonucleaseIII digestion of specific linear chimeric histone DNA plasmids followed by hybridization with mRNAs demonstrated the existence of all five histone genes on one strand of DNA and the 5'-3' polarity of that strand . These results, in conjunction with the data of Wu et al . (1976), allow us to construct a map of coding and spacer sequences in the transcribed strand of S . purpuratus histone gene repeat unit: (see article).

Biokhimiia, 1976 Sep, 41(9), 1641 - 5
{Interaction of dansyl-dipeptidyl-tRNA with E . coli ribosomes}; Vigestane RIa et al.; Dansyl-dipeptidyl-tRNA is found to bind with ribosomes in the presence of polyU much more efficiently than AcPhe-tRNA . 30-80% OF introduced danysl-dipeptidyl-tRNA is in a complex with ribosomes and reacts with puromycin in the presence of 5 mM Mg2+ . A significant binding of dansyl-dipeptidyl-tRNA both for acceptor and donor ribosome regions is observed in the presence of 10 mMg2+, unlike AcPhe-tRNA, which is capable of the binding only at 20 mM Mg2+ . A peptide transfer from dansyl-dipeptidyl-tRNA on puromycin takes place at 10 mM Mg2+ in the absence of template, while AcPhe-tRNA efficiently interacts with puromycin only at 20 mM Mg2+ . The data obtained suggest that the increase of hydrophobity of a peptide residue in peptidyl-tRNA increases its binding in peptidyl transferase of ribosomes.

Nucleic Acids Res, 1976 Sep, 3(9), 2207 - 22
The kinetics of E . coli RNA polymerase; Solage A et al.; Using an assay specific for chain elongation of E . coli RNA polymerase the kinetics of this propagation reaction have been studied . The kinetic behaviour is consistent woth the mathematical model formulated for this multisubstrate enzyme . The effect of increasing salt concentration on the kinetics of the reaction indicated that DNA unwinding is probably a necessary step in the propagation step, although this may not be the rate limiting step under all conditions.

Med Klin, 1976 Aug 27, 71(35), 1372 - 6
{Significance of indirect hemagglutination test with polyvalent E . coli O antigens to diagnosis of pyelonephritis (author's transl)}; Strohm WD et al.; 78% of 32 patients with acute E . coli pyelonephritis had significantly increased antibody titers to polyvalent E . coli antigens (PA) . Only 14% of 42 patients with chronic E . coli pyelonephritis had increased antibody titers . 143 E . coli O groups were used in hemagglutination test distributed into 8 antigen pools . Antibody titers to common O groups were more elevated than those to uncommon O groups . The result showed that hemagglutination test with PA can be usefull for serologic diagnostic of acute pyelonephritis.

Nucleic Acids Res, 1976 Aug, 3(8), 1961 - 71
Integration of synthetic globin genes into an E . coli plasmid; Wood KO et al.; Rabbit globin mRNA has been purified and used as a template by reverse transcriptase . The resulting duplex molecule consisting of rabbit globin mRNA/cNDA has been linked in vitro to Eco RI cleaved plasmid Col E1 DNA . Transformation of E . coli C6OO by this recombinant molecule has been achieved . Transformed bacteria acquire the colicin EQ immunity of Col E1 and a closed circular DNA species of 4.40-4.45 x 10 (6) daltons in molecular weight, an increase of 2.0-2.5 x 10(5) daltons compared to that of the parent plasmid DNA . In addition , 3H cDNA synthesized from globin RNA hybridized perferentially to the recombinant plasmid DNA.

Nucleic Acids Res, 1976 Aug, 3(8), 1883 - 902
Evidence that 16S RNA from E . coli can assume two different biologically active conformations; Hochkeppel HK et al.; We have recently shown that 16S RNA can be extracted from 30S ribosomes by an acetic acid-urea precipitation procedure which yields RNA capable of binding 13 individual ribosomal proteins . This is in contrast to phenol extracted 16S RNA which can specifically associate with only 7 proteins2-7 . In the experiments reported here, we demonstrate that the difference in protein binding capacities is due to a relatiely more "open" configuration possessed by the acetic acid-urea 16S RNA . Under identical conditions, acetic acid-urea 16S RNA is more susceptible to limited T1-RNase digestion than is phenol-16S RNA . In addition, acetic acid-urea RNA shows a relatively slower electrophoretic mobility . The observable difference in conformation between the two types of RNA is lost by storage at-70 degrees C . This loss is accompanied by a reduction in protein binding capacity of the acetic acid-urea 16S RNA.

Cell, 1976 Aug, 8(4), 581 - 94
In vitro processing of E . coli tRNA precursors; Schedl P et al.; Using E . coli tRNA precursors isolated from an RNAase P mutant strain, we have studied the steps required for the formation of tRNAs having a mature primary sequence in vitro . Our results suggest that at least three different enzymatic activities can participate in the processing of tRNA precursors.

Boll Ist Sieroter Milan, 1976 Jul 31, 55(3), 191 - 4
Comparative mutagenicity test of dyes on E . coli WP2 and S . typhimurium as indicator organisms; Tamaro M et al.; The mutagenic activity of some industrial dyes has been studied . None of these chemical substances reverted E . coli WP2 and S . typhimurium, regardless of their chemical structure, either in the direct test or in the liver microsomal assay.

Mol Gen Genet, 1976 Jul 5, 146(1), 43 - 50
Conjugation deficient E . coli K12 F- mutants with heptose-less lipopolysaccharide; Havekes LM et al.; Two F- mutants deficient in conjugation with F-type donors are isolated and characterized . Phenotypically, these mutants are similar; they have heptose-less lipopolysaccharide and lack some outer membrane protein . Genotypically, they are different . One mutant harbors a point mutation in the 70 to 74 min region, while the other is deleted for the chromosomal region 6.5 to 8.5 min . Comparison of the properties of the conjugation-deficient mutants described in this paper with other such mutants suggests that an outer membrane protein is the receptor for the f-pilus.

Mol Gen Genet, 1976 Jul 5, 146(1), 37 - 41
Inducible, error-free DNA Repair in tsl recA mutants of E . coli; Mount DW et al.; Host of cell reactivation and UV reactivation and mutagenesis of UV-irradiated phage mu were measured in tsl recAplus and tsl recA host mutants . Host cell reactivation was slightly more efficient in the tsl recA strain . Phage was UV-reactivated in the tsl recA strain with about one-half the efficiency of that in the wild type strain, but there was no corresponding mutagenesis of phage . UV-reactivation was also slightly lower and mutagenesis several-fold lower than normal in the tsl recAplus strain . To account for these observations, we propose that there is an inducible, error-free pathway of DNA repair in E . coli that competes with error-prone repair for repair of phage lesions.

Mikrobiyol Bul, 1976 Jul, 10(3), 325 - 33
{106 cases of infantile diarrhea caused by enteropathogenic E . coli 0111:B4 serotype in a 1974 epidemic in Ankara}; Berkman E; 106 Enteropathogenic E . coli (E.P.E.C.) 0111 : B4 were isolated from the stools of children with gastro enteritis . 101 of these came from different pediatric wards, 5 . from outpatient clinics with no history of previous hospital contact . In 16 months different E.P.E.C . serotypes were isolated, these are shown table VI . In spite of the uniformity of the serotype isolated during 1974 epidemic various serotypes were isolated in subsequent years . Among these serotypes 0111 : B4 was most prevalent, consisting of 47.3% of all isolations.

Int J Radiat Biol Relat Stud Phys Chem Med, 1976 Jul, 30(1), 67 - 78
The analysis of single-strand breaks in E . coli using a curve-fitting procedure; Fox RA; A curve-fitting technique has been used to analyse the activity profiles occurring when the tritium labelled DNA of irradiated E . coli is sedimented in an alkaline sucrose gradient . The fitted curve is a modification of an expression derived elsewhere, which assumes that DNA of unit length undergoes scissions at random positions on the DNA strand . The theoretical curves fit the data well, even after considerable repair or excision of the radiation damage has been effected by cellular enzymes . The profile resulting from sedimentation of unirradiated DNA may be fitted with the same theoretical expression provided that the velocity of centrifugation is not too high . The number of single-strand breaks derived from the analysis is almost unaffected by the presence of extraneous activity at the top or bottom of the sucrose gradient . The method is therefore more reliable than many other methods used to analyse sedimentation data.

Mol Biol Rep, 1976 Jul, 2(6), 487 - 95
Conformational peculiarities of tRNAMetf from E . coli as revealed by fluorescent methods; Surovaya AN et al.; Conformational transitions in several individual tRNAs (tRNAMetf, tRNAPhe from E . coli, tRNAVal1, tRNASer, tRNAPhe from yeast) have been studied under various environmental conditions . The binding isotherms studies for dyes-tRNA complexes exhibited similarities in conformational states of all tRNAs investigated at low ionic strength (0.01 M NaCl) . By contrast, at high ionic strength (0.4 M NaCl or 2 X 10(-4) M Mg2+) a marked difference is found in structural features of tRNAMetf as compared with other tRNAs used . The tRNAMetf is the only tRNA species that does not reveal the strong type of complexes with ethidium bromide, acriflavine and acridine orange.

Int J Radiat Biol Relat Stud Phys Chem Med, 1976 Jun, 29(6), 501 - 11
Role of peroxide in the radioprotective action of thiols in E . coli; Naslund M et al.; The radioprotective action of cysteamine (MEA) and cysteine in E . coli is due partly to autoxidatively generated hydrogen peroxide (H2O2) . This effect, which predominates at low concentrations of the thiols (1-2 mM in neutral solution), is regularly correlated with a metabolic block, measured as inhibition of RNA synthesis . In experiments with E . coli 15 (autotroph) under exponential growth in complete medium, the role of H2O2 was demonstrated by (a) a decreased radioprotective action if catalase was present in the medium; (b) a radioprotective action of H2O2 added to the medium; (c) a decreased protective action in the absence of catalytically active copper; and (d) oxygen being required for the radioprotective action to develop . At higher concentrations of the thiols, their radioprotective action, and the accompanying metabolic block, are less dependent on H2O2 generation and presumably due to a different mechanism . The radioprotective action of H2O2 is possibly related to the radioprotective action in mammals of catalase inhibitors.

Cell, 1976 Jun, 8(2), 245 - 55
Association of the folded chromosome with the cell envelope of E . coli: characterization of the proteins at the DNA-membrane attachment site; Portalier R et al.; Gentle lysis of E . coli cells in the presence of a DNA counterion (either 1.0 M NaCl or 5 mM spermidine) permits the isolation of the folded intact bacterial chromosome associated with membrane fragments . Most of the proteins in these chromosomes are also found in purified membrane preparations, and they can be identified as belonging to either the inner or the outer bacterial membrane . Ultraviolet irradiation of the membrane-attached chromosomes causes the formation of a stable complex between two inner membrane proteins (molecular weight 80,000 and 56,000 daltons) and 5-bromodeoxyuridine (BrdU)-substituted DNA . The photochemical attachment of BrdU-substituted DNA to specific membrane proteins suggests that these proteins may be bound to the DNA in vivo . Such DNA-membrane-binding proteins may have a role in the attachment of the folded chromosome to the bacterial envelope.

J Hyg (Lond), 1976 Jun, 76(3), 403 - 6
The distribution of serotypes of Escherichia coli in cow-pats and other animal material compared with serotypes of E . coli isolated from human sources; Bettelheim KA et al.; The serotypes of 13,139 strains of Escherichia coli isolated from humans were compared with the serotypes of 1076 strains isolated from animals . 689 of these strains were isolated from fresh cow-pats on 22 sites in England and Wales . 708 different O/H combinations were found . Of these, 520 were found in human strains only, 130 from animal strains only and 58 O/H serotypes from humans and animals . Approximately half of the animal strains could not be typed with the full set of sera used.

J Immunol, 1976 Jun, 116(6), 1554 - 60
Enzyme-linked immunoassay: conjugation of the Fab' fragment of rabbit IgG with beta-D-galactosidase from E . coli and its use for immunoassay; Kato K et al.; 1 . A method for the conjugation of the Fab' fragment of rabbit IgG with beta-D-galactosidase from Escherichia coli is described . The method consists of two main steps: treatment of the Fab' fragments containing sulfhydryl groups with excess N,N'-o-phenylenedimaleimide, to introduce maleimide residues into the fragments, and then incubation of the dimaleimide-treated Fab' fragments with beta-D-galactosidase, which also contains sulfhydryl groups, to form the rabbit Fab'-beta-D-galactosidase complex . More than 90% of the enzyme used can be converted to the Fab'-enzyme complex, and the complex is readily separated from free Fab' fragments by chromatography on a Sepharose 6B column . 2 . The application of the rabbit Fab'-beta-D-galactosidase complex for immunoassay of macromolecular antigens is shown by measuring human IgG by the sandwich method . The rabbit (anti-human IgG) IgG-coupled Sepharose 4B is incubated with human IgG and then with the rabbit (anti-human IgG) Fab'-enzyme complex, and the enzyme activity bound to the Sepharose is measured . In this way it is possible to determine as little as 0.3 fmoles of human IgG.

Nucleic Acids Res, 1976 Jun, 3(6), 1577 - 90
Affinity labelling of phenylalanyl-tRNA synthetase from E . coli MRE-600 by E . coli tRNAphe containing photoreactive group; Gorshkova II et al.; The photoinduced reaction of phenylalanyl-tRNA synthetase (E.C.6.1.1.20) from E.coli MRE-600 with tRNAphe containing photoreative p-N3-C6H4-NHCOCH2-group attached to 4-thiouridine sU8 (azido-tRNAphe) was investigated . The attachment of this group does not influence the dissociation constant of the complex of Phe-tRNAphe with the enzyme, however it results in sevenfold increase of Km in the enzymatic aminoacylation of tRNAphe . Under irradiation at 300 nm at pH 5.8 the covalent binding of {14C}-Phe-azido-tRNAphe to the enzyme takes place 0.3 moles of the reagent being attached per mole of the enzyme . tRNA prevents the reaction . Phenylalanine, ATP,ADP,AMP, adenosine and pyrophosphate (2.5 xx 10(-3) M) don't affect neither the stability of the tRNA-enzyme complex nor the rate of the affinity labelling . The presence of the mixture of either phenylalanine or phenylalaninol with ATP as well as phenylalaninol adenylate exhibits 50% inhibition of the photoinduced reaction . Therefore, the reaction of {14C}-Phe-azido-tRNA with the enzyme is significantly less sensitive to the presence of the ligands than the reaction of chlorambucilyl-tRNA with the reactive group attached to the acceptor end of the tRNA studied in 1 . It has been concluded that the kinetics of the affinity labelling does permit to discriminate the influence of the low molecular weight ligands of the enzyme on the different sites of the tRNA enzyme interaction.

Zh Mikrobiol Epidemiol Immunobiol, 1976 Jun, (6), 100 - 4
{alpha-Hemolysin of E . coli}; Palkina NA; The activity of alpha-hemolysin increased at the log growth phase in the culture of E . coli P678 Hly+ hemolytic strain; this activity diminished with the change into the stationary phase, and then fell sharply . Replacement of the culture medium in the stationary growth phase by fresh one led to restoration of the hemolytic activity of the culture . The culture fluid separated from the cells at the stationary growth phase produced an inhibitory action on the alpha-hemolysin Ca ions activated and stabilized the alpha-hemolysin . Sodium citrate and sucrose served as hemolysis inhibitors . The action of alpha-hemolysin was maximal against human erythrocytes at pH 6.5 . Hemolytic activity was characterized in time by a distinct lag-phase and the phase of the greatest rate of reaction . The duration of the lag-phase and also the rate of hemolysis depended on the concentration of alpha-hemolysin (with the increase of the hemolysin concentration lag-phase was shortened and the reaction was accelerated) . There proved to be a linear relationship between the amount of erythrocytes taken into the reaction and the rate of hemoglobin release, and also there was noted a temperature activation of the hemolytic reaction.

Mol Gen Genet, 1976 May 7, 145(2), 207 - 13
lamB mutations in E . coli K12: growth of lambda host range mutants and effect of nonsense suppressors; Hofnung M et al.; Over sixty EMS induced mutations affecting gene lamB, presumably the structural gene for the lambda receptor in Escherichia coli K12, were examined for growth of lambda host range mutants and effect of nonsense suppressors . By the first criterion the mutations could be grouped in three classes . Bacteria with class I mutations allow growth of lambda mutants with extended host range (noted lambdah) of the type already described (Appleyard, MacGregor and Baird, 1956) . Bacteria with class II mutations allow growth of lambdah mutants with still more extended host range (noted lambdahh) . No host range mutants of lambda could be found which would grow on bacteria with class III mutations . Using nonsense suppressors it was found that class I and II consist of missense mutations, while class III consists of nonsense mutations . Exceptions are likely to exist (especially in class III) but were not found among the mutations tested . These observations are briefly discussed in terms of outer membrane protein integration and of phage receptor interaction.

Mol Gen Genet, 1976 May 7, 145(2), 183 - 90
Replication of E . coli duplex DNA in vitro . The separation of the DNA containing fractions of a lysate from the soluble enzymes and their complementation properties; Nusslein V et al.; An E . coli lysate after being gently washed to remove soluble components, supports replicative DNA synthesis, if soluble proteins and the deoxyribonucleotide triphosphates are added . This DNA synthesis is dependent on ATP and on the presence of the gene products of the dnaB, dnaG, and polC (DNA polymerase III) genes . It continues at the replication forks preformed in vivo and "Okazaki fragments" are intermediate products of the reaction . Two different methods were used to prepare the washed DNA containing fraction . The one method involves washing of a cell lysate situated on a dialysis membrane . The other method involves DNAase treatment of a lysate and sedimentation of the degraded DNA through a glycerol gradient . Both washed preparation contain not only the DNA and the replication forks but also functional amounts of DNA polymerase III and of the dnaB gene product . Other factors, that are essential for replicative DNA synthesis, including the dnaG gene product, are washed out of the DNA containing preparations and the system is reconstituted by readdition of the soluble proteins.

Nature, 1976 May 6, 261(5555), 23 - 6
Abundance and membrane association of elongation factor Tu in E . coli; Jacobson GR et al.; Elongation factor Tu is present in a fourfold excess over the amount seemingly involved in protein synthesis . It is identical to a major protein which we have found associated with the plasma membrane . The possibility of a specific role in that location is considered.

Biochemistry, 1976 May 4, 15(9), 1994 - 2001
A quantitation of the factors which affect the hydrolase and transgalactosylase activities of beta-galactosidase (E . coli) on lactose; Huber RE et al.; A study was implemented to quantitate the hydrolase and transgalactosylase activities of beta-galactosidase (E . coli) with lactose as the substrate and to investigate various factors which affect these activities . At low lactose concentrations the rate of galactose production was equal to the rate of glucose production . The rate of galactose production relative to glucose, however, dropped dramatically at lactose concentrations higher than 0.05 M and production of trisaccharides and tetrasaccharides began (galactose/glucose ratios of about 2:1 and 3:1, respectively, were found for these two types of oligosaccharides) . At least five different trissacharides were formed and their patterns of formation showed that they probably utilized both lactose and allolactose as galactosyl acceptors . Allolactose was produced in amounts proportional to glucose at all lactose concentrations (ratios of allolactose/glucose were about 0.88) . Analyses of various data, including a reaction analyzed at very early times, showed that the major means of production of allolactose (and the only means initially) was the direct enzymatic transfer of galactose from the 4 position to the 6 position of the glucose moiety of lactose without prior release of glucose from the enzyme . It was shown, however, that allolactose could also be formed in significant quantities by the transfer of galactose to the 6 position of free glucose, and also by hydrolysis of preformed trisaccharide . A mechanism which fits the initial velocity data was proposed in which the steps involving the formation of an enzyme-gallactose-glucose complex, the formation and breakage of allolactose on the enzyme, and the release of glucose all seem to be of roughly equal magnitude and rate determining . Various factors affected the amounts of transgalactosylase and hydrolase activities occurring . At high pH values (greater than 7.8) the transgalactosylase/hydrolyase activity ratio increased dramatically while it decreased at low pH values (less than 6.0) . At mid pH values the ratio was essentially constant . The absence of Mg2+ caused a large decrease in the transgalactosylase/hydrolase activity ratio while the absence of all but traces of Na+ or K+ had no effect . The anomeric configuration of lactose altered the transgalactosylase/hydrolase activity ratios, alpha-Lactose resulted in a decrease of allolactose production (transgalactosylase activity) relative to hydrolase activities (glucose production) while beta-lactose had the opposite effect.

Mol Biol (Mosk), 1976 May-Jun, 10(2), 604 - 8
{Effect of oligoribonucleotides specifically bound by E . coli RNA-polymerase on DNA-dependent RNA synthesis}; Knorre VL et al.; It was shown previously that E . coli RNA-polymerase (EC 2.7.7.6) selectively binds certain fractions of penta- or hexaribonucleotides random mixtures (Knorre V . L., Vasilenko S . V., Salganik R . I., FEBS Lett., 30, 229, 1973) . The data obtained demonstrate that such oligoribonucleotides compete with DNA for the RNA polymerase active centre and inhibit DNA dependent RNA synthesis catalyzed by the enzyme . These properties are absent in tri- and tetraribonucleotides which cannot be bound by RNA polymerase . The inhibitory action of the pentaribonucleotides was higher when they had been added prior to DNA to the mixture containing RNA polymerase.

Biokhimiia, 1976 May, 41(5), 768 - 80
{Rate of ribosome movement along messenger RNA in E . coli under normal and inhibited translation}; Arbuzov VA et al.; Considerable decrease of polysome number (22% as compared with 48% in normally grown culture) was observed under methionine starvation of E . coli Hfr (Met-)culture . At the same time the amount of 70S ribosomes increased up to 32%, while it was 2--6% in the control, the content of free ribosome subunits (50S+30S) being stable . The number of polysomes was the same (congruent to 50%) both in the control culture and under inhibition of protein synthesis in E . coli Hfr(Met-) cells with chloramphenicol, the content of 70S ribosomes was increased (30%) like in the case of methionine starvation, and the amount of free ribosome subunits was decreased (24% as compared with 46% in the control) . The rate of ribosome movement in polysomes in the presence of chloramphenicol is comparable with that in the control . The rate of ribosome movement along mRNA under methionine starvation in 1.6 times lower than in normally grown E.coli culture . The level of (14)C-leucine incorporation into newly synthesizing polysome proteins under chloramphenicol inhibition of protein synthesis and methionine starvation comprised 20% and 12% of the incorporation level inthe control respectively . It suggested that ribosomes under inhibition of protein synthesis by chloramphenicol or amino acid starvation continue their movement along mRNA with the rate comparable with that in the control . However in this case no peptide bonds are formed ("abortive" translocation).

Brookhaven Symp Biol, 1976 May, (27), V12 - V23
The production of deuterated E . coli; Moore PB et al.; Our results indicate that the preparation of deuterated macromolecules for neutron scattering from E . coli can be done easily and relatively cheaply . The entry of deuterium into macromolecules of differing species during cell growth can be controlled by varying the D2O content of the medium and the choice of carbon sources, all in minimal medium . Considering the range of deuterations obtainable with simple protonated carbon sources, there seems to be no reason to use deuterated carbon sources except for the rare occasions when a fully deuterated specimen is required.

Brookhaven Symp Biol, 1976 May, (27), IV38 - IV48
Neutron scattering measurements with the label triangulation method on the 50 S subunit of E . coli ribosomes; Hoppe W et al.; In the E . coli 50 S ribosomal subunit, proteins L7/L12 and L10 were deuterated by partial reconstitution . The distance between L7/L12 and L10 was measured by the label triangulation method and was found to be approximately 100 A or, with low probability, 60 to 70 A, depending on the concentration.

Cell, 1976 May, 8(1), 129 - 38
Identification of genes for elongation factor Ts and ribosomal protein S2 in E . coli; Yamamoto M et al.; The structural gene for elongation factor EF-TS (tsf) and that for ribosomal protein S2 (rpsB) have been identified in E . coli . Both genes are carried by lambda transducing phages that have been isolated as dapD+polC+ transducing phages . Synthesis of both S2 and EF-Ts was demonstrated in ultraviolet light-irradiated E . coli cells infected with these phages . Experiments were also done using other transducing phages that carry dapD+ but not polC+ . The data indicate that both the tsf and rpsB genes map near dapD at about 4 min on the E . coli genetic map . This location is different from the two chromosomal locations, the str-spc region and the rif region, where many ribosomal protein genes, the genes for RNA polymerase components, as well as other elongation factor genes (fus, tufA, and tufB) are located.

Zh Mikrobiol Epidemiol Immunobiol, 1976 May, (5), 117 - 21
{Temperature-dependent mutants of Hly plasmid and their use for the purpose of confirming the cytotoxic activity of E . coli hemolysin}; Ratiner IuA et al.; Two different mutants of Hly 212 plasmide induced by diethyl sulfate were isolated; one of these was characterized by temperature-dependent synthesis, and the other--by temperature-sensitivity of hemolysin produced . In difference from bacteria possessing wild parental plasmide, E . coli K12 bacteria which contained the mutants produced no cytotoxic action on the MK2 cell culture . This correlated with the absence of the hemolytic activity in growing them even at permissible temperature on medium No 199 . After crossing the mutant plasmides there were obtained clones with completely restored wild phenotype of the hemolysin production and the cytotoxic activity . The data obtained pointed to the relationship between the cytotoxicity and hemolysin.

Nucleic Acids Res, 1976 May, 3(5), 1185 - 201
The involvement of the anticodon adjacent modified nucleoside N-(9-(BETA-D-ribofuranosyl) purine-6-ylcarbamoyl)-threonine in the biological function of E . coli tRNAile; Miller JP et al.; tRNAile was isolated from E . coli Cp 79 (leu-, arg-, thr-, his-, thiamin-, RCrel) which had been grown on a sub-optimal concentration of thr and was found to contain an average of 50% less N-{9-(beta-D-ribofuranosyl)- purin-6-ylcarbamoyl}threonine, t6Ado, than tRNAile from cells grown on an optimum concentration of thr and containing a normal complement of t6Ado . The two tRNA's were identical in their ability to be aminoacylated, to accept the 3'-terminal dinucleotide, and to form an ile-tRNAile-Tu-GTP complex . In contrast, the t6Ado-deficient-tRNA was significantly less efficient in binding to ribosomes compared to the normal tRNA . This difference was seen in the binding of deacylated tRNA and in the nonenzymatic and enzymatic binding of ile-tRNA, all in response to poly AUC . The t6Ado-deficient ile-tRNA demonstrated no binding at Mg2+ concentrations less than or equal to 10 mM, while the normal ile-tRNA bound at low Mg2+ concentrations . Tetracycline had the same effect on the normal as on the t6Ado-deficient ile-tRNA binding . As a control, the binding of phe-tRNA (which does not contain t6Ado) from normal and thr-starved cells in response to poly U was identical . It was concluded that t6Ado is required for proper codon-anticodon interaction.

Biull Eksp Biol Med, 1976 May, 81(5), 568 - 70
{Cytopathogenic action of E . coli strains, containing corresponding ABO type heterogeneous antigens, on transplantable human cells}; Podoplelov II et al.; A study was made (in vitro) of the interaction of various strains of E . coli, serological type O26 with continuous human cells (HeLa, Tg-33 and RH) . Phenomenon of the cytopathogenic action of uropathogenic E . coli strains, containing heterogenous antigens, type O(H) and B, on the human cell strains possessing corresponding isoantigens was revealed on the 6th hour of the interaction . The number of dead cells in these cultures exceeded (1.5--3 times) their count cultures to which E . coli containing no heterogenous antigens or containing different human heterogenous antigens of the ABO type were added . It is supposed that this phenomenon played an important role in the development of chronic forms of colibacterial pyelonephritis.

Biophys Chem, 1976 May, 4(3), 253 - 7
Pressure-jump relaxation studies of the association--dissociation reaction of E . coli ribosomes; Schulz E et al.; The association--dissociation kinetics of ribosomal particles from E . coli have been studied using a pressure-jump apparatus with optical detection . Experiments on isolated subunits yield two relaxation times of about 10 and 700 ms, respectively . With mixtures of 30 S and 50 S particles an additional relaxation time of about 100 ms is observed, which is assigned to the equilibrium 30 S + 50 S in equilibrium 70 S . The two other times are attributed to reversible equilibria between subunit monomers and subunit homo-associates.

Tijdschr Diergeneeskd, 1976 May 1, 101(9), 481 - 90
{E . coli enterotoxicosis in unweaned piglets . IV . Evaluation of results obtained on using an adjuvant vaccine in the field (author's transl)}; Rozemond H; The results obtained on using an adjuvant vaccine against enterotoxaemia caused by E . coli in suckling piglets are discussed on the basis of an inquiry conducted among a number of veterinary practitioners . The vaccine contains the OK groups O138:K81,K88, O141:K85ab and O149:K91,K88 and is administered parenterally to the dams during the latter half of gestation . The inquiry which covered 4,000 sows on fifty-five farms showed that, as regards diarrhoea during the first week of life, morbidity in the offspring of vaccinated sows decreased from 83 per cent to 6 per cent and that mortality dropped from 23 per cent to 0.3 per cent . Clinical results were slightly less satisfactory where diarrhoea during the second and third weeks of life was concerned . The importance of serological typing prior to vaccination is stressed . Abortion occurred in 0.5 per cent of the vaccinated sows within three days after vaccination . The question is raised whether there is a relationship between this vaccination and abortion.

Tijdschr Diergeneeskd, 1976 May 1, 101(9), 470 - 80
{E . coli enterotoxicosis in unweaned piglets . III . Preparation and use of vaccines in enterotoxaemia due to E . coli in newborn piglets in the Netherlands}; Hill WK et al.; The preparation of a number of E . coli vaccines designed to prevent enterotoxicosis due to E . coli in young piglets is discussed . The results of laboratory experiments concerned with the production of haemagglutinating antibodies in pigs following inoculation of this vaccine are reported . This oil-adjuvant vaccine (OAV) was used in the field in thirty-one herds in which enterotoxicosis due to E . coli was a recurrent problem . It is concluded from serological and clinical observations that the use of this vaccine is advisable on farms on which enterotoxicosis due to E . coli occurs in young piglets.

Tijdschr Diergeneeskd, 1976 May 1, 101(9), 461 - 9
{E . coli enterotoxicosis in unweaned piglets . II . Preparation and preventive administration of immunoglobulins (author's transl)}; Bokhout BA et al.; Laboratory and field trials were made of an immunoglobulin prepared from sows hyperimmunized with E . coli O149:K91,K88 . Of the three methods of inoculation (oral, intramuscular and intraperitoneal) used in laboratory trials in specific pathogen-free (SPF) piglets, oral administration was found to result in the lowest concentration of immunoglobulin in the serum of the piglets . There was little difference between the concentration of immunoglobulin in the serum of the piglets following intramuscular administration and that following intrperitoneal administration . Oral and intraperitoneal inoculation of preparations of immunoglobulin were adopted in three herds in which enterotoxaemia caused by E . coli O149:K91,K88 was a recurrent problem . It can be concluded from these experiments that administration of immunoglobulins does offer some, but definitely inadequate, protection as a preventive measure in enterotoxaemia due to E . coli.

Tijdschr Diergeneeskd, 1976 May 1, 101(9), 458 - 60
{E . coli enterotoxicosis in unweaned piglets . I . Some concepts (author's transl)}; Rozemond H et al.; In a brief review, attention is drawn to a number of findings on infections with enteropathogenic E . coli in suckling piglets: serological typinge K88 antigen, colonisation, enterotoxin production and enterosorption, absence of symptoms of inflammation in the bowel wall and significance of the various immunoglobulin classes . The term E . coli enterotoxicosis used to designate the disease is preferred to terms such as E . coli diarrhoea, E . coli enteritis and (enterotoxic) colibacillosis.

Mol Gen Genet, 1976 Apr 23, 145(1), 19 - 22
Identification of a mutation within the structural gene for the a subunit of DNA-dependent RNA polymerase of E . coli; Fujiki H et al.; An E . coli mutant rpoA109 unable to support the growth of phage P2 produces DNA-dependent RNA polymerase with an altered alpha subunit . Histidine is substituted for leucine in one tryptic peptide from the mutant alpha subunit . The existence of only one rpoA gene within the E . coli chromosome is indicated.

Mol Gen Genet, 1976 Apr 23, 145(1), 109 - 10
Transformation in E . coli K12: relation of linkage to distance between markers; Hoekstra WP et al.; E . coli K12 transformants, selected as leu+ or pyrA+ transformants, were analysed for inheritance of some closely linked unselected markers . Based on the observation that the number of recombinants which require, besides an integration event, one or more crossing-over events was negligible, a simple mapping function was deduced . The function L= e-kd, which directly relates observed linkage of an unselected marker and the relative distance of that unselected marker to the selected marker, gave a consistent interpretation of the experimental results.

Biokhimiia, 1976 Apr, 41(4), 650 - 4
{Simple method for isolation of three DNA-polymerases from E . coli using chromatography on DNA-cellulose}; Khlebalin OI et al.; A simple method for isolation of three DNA-polymerases from E . coli is developed; it is based on properties of the enzymes to bind with single-stranded DNA, fixed on cellulose . DNA-polymerases I, II and III were identified by their relation to templates, ionic strength, heat denaturation and inhibition of the activity with agents which blocked sulfhydryl groups . After purification which included chromatography on DNA-cellulose as well as fractionation with phosphocellulose and gel-filtration through Sephadex G-100, the enzymes were free the endonucleases contamination.

Cell, 1976 Apr, 7(4), 517 - 30
The structures and fidelity of replication of mouse mitochondrial DNA-pSC 101 EcoRI recombinant plasmids grown in E . coli K12; Brown WM et al.; Recombinant DNAs containing the E . coli plasmid pSC101 and mouse cell (La9) mitochondrial DNA (mtDNA) were formed in vitro via ligation of DNA fragments from limit EcoRI endonuclease digests and were used to transform E . coli K12 . Four structurally different recombinant plasmid DNAs from transformed clones were characterized . Two of these were analyzed extensively and the mtDNA portions compared with mtDNA from LA9 cells . No differences were detected in the physical or chemical properties examined, except that the E . coli mtDNA lacked the alkali lability characteristic of animal mtDNAs . Heteroduplexes between the LA9 portions of the recombinant plasmids and LA9 mtDNA were analyzed by absorbance melting . The melting temperatures were indistinguishable from reannealed LA9 mtDNA homoduplexes, indicating that single-base replication errors occur at a frequency of fewer than 1 nucleotide in 300 . Electron microscopic analyses of plasmid-LA9 mtDNA heteroduplexes and a comparison of agarose gel electrophoresis of restriction endonuclease fragments also indicated no differences . These results were independent of the order or the relative orientation of the pSC101 and mtDNA fragments . A third EcoRI fragment in LA9 mtDNA, not found in an earlier study (Brown and Vinograd, 1974), has been positioned in the LA9, EcoRI map . This fragment contains 165+/-10 nucleotide pairs.

Nucleic Acids Res, 1976 Apr, 3(4), 965 - 75
Anticodon conformation and accessibility in wild-type and suppressor tryptophan tRNA from E . coli; Buckingham RH; The association between Trp-tRNA and Pro-tRNA, which have complementary anticodon sequences, has been used as a probe of anticodon conformation . It is unaffected, however, by the base change in the D-stem present in UGA-suppressor Trp-tRNA . This does not support the hypothesis that UGA suppression depends upon a conformational change induced in the anticodon . The stable denatured form of wild-type Trp-tRNA no longer interacts with Pro-tRNA; the structure of the anticodon region must therefore be quite different in the denatured form.

Acta Pathol Microbiol Scand {C}, 1976 Apr, 84(2), 131 - 4
Influence of hydrocortisone on uptake and elimination of 32P-labelled E . coli by rat polymorphonuclear neutrophils (PMN) in vitro; Baardsen A; Hydrocortisone was tested for inhibition of uptake and of elimination of E . coli by monolayers of rat peritoneal PMN . 32P was used as label of the bacteria and their degradation products eliminated from the phagocytes . The cellular uptake was reduced by hydrocortisone (1-2 mg per ml) both in the presence and absence of serum, while the elimination of bacterial label was reduced by 0.5 mg per ml and higher concentrations of the drug.

Acta Pathol Microbiol Scand {C}, 1976 Apr, 84(2), 100 - 4
Elimination of ingested 32P-labelled E . coli from rat polymorphonuclear neutrophils (PMN) . Evaluation of a method; Midtvedt T et al.; A method to be used for in vitro assay of the elimination of ingested 32P-labelled E . coli from rat PMN monolayers has been evaluated . The rate of expulsion of bacterial label from phagocytes into the extracellular medium was found to range between 40 and 50% of the total uptake 180 min after termination of ingestion . Serum enhanced the cellular uptake of bacteria, but did not affect the rate of elimination . Disintegration of the phagocytes was not found to be a problem.

J Immunol, 1976 Apr, 116(4), 1129 - 33
The effect of serum inhibitor on the antigenic and mitogenic responses to E . coli bacteria; Poe WJ et al.; The effect of serum inhibitory factors on the induction of the in vitro immune response and mitogenic response to Escherichia coli antigens in murine spleen cell cultures was investigated . Both normal and congenitally athymic mice served as spleen cell and serum donors . Cultured CBA/J spleen cells produced anti-bacterial antibody in the presence of mouse serum, but the mitogenic response to the bacterial antigen was suppressed by the addition of mouse serum . The addition of mouse serum from either CBA/J or nude mice to nude spleen cell cultures led to suppression of both the antigenic and mitogenic responses to bacterial antigen . The polyclonal antibody response by CBA/J spleen cell cultures to SRBC induced by bacteria was significantly enhanced by the addition of either CBA/J or nude mouse serum . Conversely, the nude spleen cell polyclonal response to SRBC was significantly inhibited by high concentrations of nude or CBA/J mouse serum . These data indicate that inhibition of the specific E . coli and nonspecific polyclonal antibody responses by mouse serum occurs only in cultures of spleen cells taken from mice lacking a population of T lymphocytes.

Mol Gen Genet, 1976 Mar 22, 144(2), 141 - 50
Detection of ribonucleic acids which are larger than 30S precursor ribosomal RNA in RNase III deficient E . coli cells; Yuki A; 1 . New high molecular weight RNA species have been found in an RNase III deficient mutant of E . coli . These RNA's were very minor but stable components of the cells, and their molecular weights, which range from 3-5.5 million daltons, are higher than that of 30S precursor ribosomal RNA . In these respects these RNAs are similar to the 2.5 M RNA reported previously (Yuki and Wittmann, 1974) . 2 . A method to analyse minor RNA components is described . A linear relationship between logarithms of molecular weights and logarithms of distance moved in 1.5-7.5% polyacrylamide concentration gradient gels is also described in this report . 3 . DNA species whose molecular weights ranged from 1.8 to 5.5 million daltons and also a species of 8 million daltons are described . two techniques commonly used to identify RNA, viz . DNase treatment and labeling with radioactive uridine, are discussed in connection with these DNAs . 4 . The determination of the molecular weight of 30S precursor ribosomal RNA is discussed and it is suggested that this RNA is heterogenous, consisting of two species of molecular weight 1.8 million daltons and 2.0 million daltons, respectively.

C R Acad Sci Hebd Seances Acad Sci D, 1976 Mar 8, 282(10), 1053 - 6
{Formation, by gamma irradiation, of RNA-protein cross-links in E . coli ribosomes}; Ekert B et al.; Gamma irradiation in desaerated conditions of E . coli MRE 600 ribosomes, labelled with C14 uracil, leads to a decrease of extractibility of C14 RNA by lithium chloride 4 M-urea 8 M . On the other hand, the radioactivity of the protein fraction increases with irradiation . These results strongly suggest that RNA-protein cross links are formed in irradiated ribosomes.

Vopr Med Khim, 1976 Mar-Apr, 22(2), 194 - 203
{Messenger RNA metabolism in E . coli under amino acid starvation conditions}; Arbuzov VA; In E . coli Hfr Kavalli (met-) turnover of mRNA was studied in normal state and in methionine deficiency . This strain of E . coli was shown to have the 'loose' type of regulation of RNA synthesis (RC-) . Without methionine in E . coli Hfr the rate of the protein synthesis was about 7-8% of that found in the control culture . In studies of the total mRNA turnover the half-life of matrices was equal to 2 min at 37degree, if a medium did not contain methionine; the same value was observed in the control culture . At the same time in methionine starvation an increase in amount of rapidly labelled RNA was observed; the RNA remained stable under simultaneous effect of actinomycin D . This rapidly labelled, stable RNA was the messenger-RNA, associated with cytoplasmic membranes . The hypothesis is advanced that membrane-associated and cytoplasmic RNA are those two types of matrices, which differed in their stability when the protein synthesis was inhibited.

Mol Biol (Mosk), 1976 Mar-Apr, 10(2), 378 - 85
{Conditions for specific oligoribonucleotide binding with E . coli RNA-polymerase}; Efimova LI et al.; RNA polymerase of E . coli (EC 2.7.7.6) is able to bind certain oligoribonucleotides with the length greater than or equal to 5 from the corresponding isoplith mixtures (Knorre V.L., Vasilenko S.V., Salganik R.I., FEBS Letters 30, 229, 1973) . It has been shown in this study that all pentaribonucleotides able to be bound by RNA polymerase can be extracted from the random mixture by the enzyme saturation procedure . Loosely and tightly bound pentaribonucleotides subfractions were isolated and each was separated by chromatography into 3-4 isopliths . Blocking of the enzyme SH groups by p-chloromercurium benzoate (10(-3) M) and denaturation by urea (6.3 M) prevent formation of the enzyme-pentaribonucleotides complexes . Complexes are destroyed by heat denaturation . Removal of sigma-subunit does not influence the enzyme capacity for pentaribonucleotides binding.

J Immunol Methods, 1976 Mar, 10(2-3), 161 - 70
An immuno-enzymatic assay of cortisol using E . coli beta-galactosidase as label; Comoglio S et al.; An enzyme-assay of cortisol was established by using E . coli beta-galactosidase as a marker . The number of cortisol residues per molecule of enzyme and the method of separation of free from antibody-bound enzyme proved to be critical factors for the assessment of the assay . A sensitivity ranging from 100 to 150 pg of cortisol per tube has been achieved . A comparsion with other methods, i.e . competitive protein binding assay, radioimmunoassay and fluorimetry, is reported.

Biokhimiia, 1976 Mar, 41(3), 420 - 5
{Modification of the method of extracting DNA-polymerase from E . coli}; Iushkova LF et al.; Described earlier method of isolation of E . coli DNA-polymerase is modified . In order to decrease the possible effect of proteases on DNA-polymerase, the time of autolysis was shortened . An additional stage of precipitation by ammonium sulfate of 65-80% of saturation was introduced . Chromatography on DEAE-Sephadex A-25 revealed 4 fractions exhibiting DNA-polymerase activity . It is established that combination of certain DNA-polymerase fractions, belonging to different peaks, significantly intensifies the enzyme activity . It may be due to the formation of enzymic complexes.

Zentralbl Bakteriol {Orig A}, 1976 Mar, 234(2), 189 - 201
Influence of E . COLI POLysaccharide on the interaction of E . coli K+ and K- with polymorphonuclear leukocytes in vitro; Rottini G et al.; Both a K+ strain and a K- strain of E . coli withstand phagocytic killing by polymorphonuclear leukocytes and do not stimulate the respiratory burst, that accompanies phagocytosis in these cells, as compared with E . coli J 53 which are extensively and rapidly killed and stimulate the respiration of leukocytes . Both K+ and K- E . coli become readily phagocytosable after removal of their polysaccharide by heat treatment and are able to stimulate oxygen consumption by PMN . Heat treated E . coli J 53 stimulate the oxygen uptake of PMN less than live E . coli J 53 . The polysaccharide extracted from either K+ or K- E . coli inhibits both phagocytosis of and the respiration stimulated by all the three heat-treated strains used . Instead the polysaccharide extracted from the phagocytosable strain J 53 stimulates the oxygen consumption of PMN exposed to the heat treated K- strain or heat treated J 53 itself.

Nucleic Acids Res, 1976 Mar, 3(3), 615 - 30
Synthesis of DNA complementary to the mRNAs for milk proteins by E . coli DNA polymerase I; Houdebine LM; E.Coli DNA polymerase I (Klenow subfragment) was used for the synthesis of complementary DNA with the mRNAs for rabbit milk proteins as templates . The cDNA formed, contained 200 nucleotides and represented about 20% of the mRNA template . The cDNA was hybridized specifically to the mRNA templates . The Klenow subfragment of the E.Coli DNA polymerase I was as efficient as the avian myeloblastosis virus reverse transcriptase in the synthesis of cDNA . The mean size of the cDNA fragments obtained with the Klenow enzyme proved to be 70% of the value obtained with the AMV reverse transcriptase and at least twice the value generally obtained with the complete E.Coli DNA polymerase I . The cDNA was used for the detection and the quantification of the mRNA template in various RNA fractions.

Biull Eksp Biol Med, 1976 Mar, 81(3), 294 - 5
{Elaboration of chloramphenicol acetyltransferase by cells of E . coli K-12 under conditions altering the intracellular concentration of cyclic adenosine-3',5'-monophosphate}; Boichenko MN et al.; The influence of cAMP, ACTH and glucose on the stimulation of chloramphenicol acetyl transferase synthesis in the cells of E . coli CSH-2/R222 and E . coli WZ-78/R222 . (cya855) was examined . Glucose proved to decrease the enzyme synthesis in E . coli CSH-2/R222, causing catabolite repression; 5 mM of cAMP and 1000 mug/ml ACTH overcame the latter . The enzyme synthesis in E . coli WZ-78/R222 was insensitive to the catabolite repression; as to ACTH - it failed to cause stimulation ofchloramphenicol acetyl transferase synthesis in E . coli WZ-78/R222.

J Trauma, 1976 Mar, 16(3), 184 - 90
Hemodynamic and respiratory responses of conscious swine to E . coli endotoxin; Brown PP et al.; The injection of a sublethal bolus of E . coli into conscious swine produces an early increase in PAP and a decrease in LAP . This hemodynamic effect may be secondary to the pulmonary venous constriction seen in other species, or may relate to demonstrated multiple pulmonary microemboli . Hypoxemia developed in only four of 17 animals although all endotoxin-treated swine showed interstitial edema and elevated wet/dry weight ratios with normal pulmonary surfactant . In addition, endotoxin-treated swine developed signs of disseminated intravascular coagulation, with renal cortical infarcts in 44%, and coronary arterial thrombi in 28% including one transmural myocardial infarction . This effect was observed in the absence of prolonged hypotension in swine and should provide a useful model for further study of the relationship of endotoxin to disseminated intravascular coagulation.

Cell, 1976 Feb, 7(2), 179 - 90
Synthesis of ribosomal RNA in E . coli: analysis using deletion mutants of a lambda transducing phage carrying ribosomal RNA genes; Yamamoto M et al.; Transducing phage lambdarifd18 carries on rRNA transcription unit containing genes for 5S, 16S, and 23S rNAs and also tRNAGlu/2 . Mutants were isolated from this phage that carry deletions removing various amounts of the distal end of this transcription unit . These deletions were physically mapped on the lambdarifd18 phage genome . Synthesis of rRNAs and of tRNAGlu/2 was examined in ultraviolet-irradiated E . coli cells infected with lambdarifd18 or with various deletion mutants . It was observed that mutant phages in which the distal end (the 5S rRNA gene and a part of the 23S rRNA gene) of the rRNA transcription unit is deleted can still synthesize both 16S rRNA (or its precursor) and tRNAGlu/2 . Apparently, the post-transcriptional cleavage that produces these RNA molecules does not require the presence of the entire transcription unit, that is, it can take place without the complete structure of the transcript ("30S pre-ribosomal RNA") . In addition, the experimental results support the gene order, 16S rRNAGlu/2, 23S rRNA, and 5S rRNA genes, in the rRNA transcription unit carried by lambdarifd18.

Cell, 1976 Feb, 7(2), 165 - 77
Transfer RNA genes between 16S and 23S rRNA genes in rRNA transcription units of E . coli; Lund E et al.; We have identified genes for tRNAGLU/2 on the transducing phages o80d3ilvsu7+ (see Ohtsubo et al., 1974) and lambdarifd18 (Kirschbaum and Konrad, 1973), and a gene for tRNAlle/1 on the transducing phage o80rifr (Konrad, Kirschbaum, and Austin, 1973) . All these phages have previously been shown to carry genes for rRNA (Ohtsubo et al., 1974; Lindahl et al., 1975; Jaskunas et al., 1975a) . We have analyzed the position of these tRNA genes by hybridizing purified RNAs to restriction fragments of the phage DNA . The tRNA genes are located inside the rRNA transcription unit in the spacer region between the 16S and 23S rRNA genes.

Genetics, 1976 Feb, 82(2), 161 - 8
Deletions induced by heat treatment of E . coli K12 lysogenic for lambda prophages; Marchelli C et al.; We have investigated the production of prophage deletions in heat-induced lambda lysogens of E . coli K12 . Our results are indicative of a direct action of the heat-induced prophage in producing deletions . The temperature of 40 degrees used for the experiments may be critical to prove this effect . The phage function involved in deletion formation is not known.

Nucleic Acids Res, 1976 Feb, 3(2), 441 - 8
A modified uridine in the anticodon of E . coli tRNA I Tyr su + oc; Altman S; The anticodon of an ochre-suppressing derivative of E . coli tRNA I Tyr, previously identified as UUA, can contain a modified uridine (U+) in the first position . The novel modified nucleotide has been identified by two-dimensional thin layer chromatography following RNase T2 digestion of anticodon-containing fragments . Up+ is found in less than stoichiometric molar yields in preparations of tRNA I Tyr su + oc . The electrophoretic mobility of Up+ is the same as Up at pH 3.5 and pH 7.5 . U+ probably does not contain sulfur since it cannot be labeled with 35S in vivo incorporation experiments.

Mol Gen Genet, 1976 Jan 16, 143(2), 203 - 9
Stimulation in trans of synthesis of E . coli gal operon enzymes by lambdoid phages during low catabolite repression; Petit-Koskas E et al.; The infection of E . coli cells with different lambdoid prophages triggers a stimulation of galactokinase synthesis when cells are grown in a medium giving rise to a mild catabolite repression (tryptone broth) with an inducer of the gal operon (fucose) . These results show that during phage infection (or induction) some factor acting in trans is produced which is able to overcome efficiently catabolite repression of the kinase cistron . Using different strains of lambdapbio252 (pam, qam, "hl), lambdapbio256Hl and lambdaNNS7 we have concluded that the factor is the N gene product which is known for its anti- p(rho) action . Studies of the whole gal operon in the same conditions show that epimerase unlike transferase and galactokinase is practically insensitive to catabolite repression by tryptone broth and that viral development has a low effect on it . This indicates that there is an internal modulation of gal operon expression . A mRNA termination site sensitive to the p factor is known in the gal operon between galE and galT . Another site weaker than this one might exist between galE and operator-promoter region.

Mol Gen Genet, 1976 Jan 16, 143(2), 177 - 84
In vitro transcription of adenovirus 2 DNA . II . Quantification and localization of promoters for E . coli RNA polymerase; Surzycki SJ et al.; We estimate that E . coli RNA polymerase is able to form stable, rifampicin-resistant, pre-intiation complexes with Adenovirus 2 DNA at three to six binding sites . The number of RNA chains initiated from such complexes has been determined form the incorporation of gamma-32P-ATP and -GTP at two rifampicin concentrations (7 mug/ml and 24 mug/ml) and after pre-incubation at either 25 or 37 degrees C . The total number of RNA chains initiated ranges from 2.6 per Ad 2 DNA molecule at a rifampicin concentration of 24 mug/ml and pre-incubation temperature of 25 degrees C, to 5.4 per Ad 2 DNA molecule at a rifampicin concentration of 7 mug/ml and pre-incubation temperature of 37 degrees C . Efficient initiation with GTP occurs only after pre-incubation at 37 degrees C whereas initiation with ATP is equally as efficient at either pre-incubation temperature . Promoters for initiation with ATP have been localized to the leftmost 58% of the Ad 2 DNA molecule, defined by the EcoR.RI restriction endonuclease fragment A; promoters for initiation with GTP are located on the remaining 42% of the Ad2 DNA molecule . It is likely that on Adenovirus 2 DNA each RNA chain is initiated from a unique binding site which constitutes a seperate promoter for E . coli RNA polymerase.

Mol Gen Genet, 1976 Jan 16, 143(2), 167 - 75
I.n vitro transcription of adenovirus 2 DNA . I . Characterization of promoters for E . coli RNA polymerase; Surzycki SJ et al.; E coli RNA polymerase holoenzyme is able to recognize transcription initiation sites on Adenovirus 2 DNA that are functionally indistinguishable from promoters for the enzyme on phage DNAs . The complexes formed between the polymerase and the DNA at these sites can exist in two states-either as I (initiation) complexes, from which rapid RNA chain initiation is not possible, or as RS (rapid starting) "rifampicin resistant" complexes, from which rapid RNA chain initiation can occur . When transcription is limited to that initiated from stable, rifmapicin-resistant pre-initiation complexes, initiation is strictly dependent on the presence of sigma factor; in addition, the frequency of initiation exhibits sigmoidal dependence on the temperature at which pre-initiation complexes are allowed to form, with a transition temperature of 26-28 degrees C . The average half-time for initiation of RNA chains from sites on Ad 2 DNA is shown to be comparable to half-times for initiation of RNA chains from promoters on T7 and lambda DNAs . At saturating levels of enzyme, the half-times are 0.6, 0.9, and 1.6 sec for lambda b2, Ad 2 and T7 DNAs, respectively . The existence of efficient, phage-like promoters for E coli RNA polymerase on Ad 2 DNA suggests to us that such promoters may be closely related functionally and spatially to promoters for mammalian RNA polymerases.

J Supramol Struct, 1976, 5(3), 291 - 308
Changes in E . coli cell envelope structure caused by uncouplers of active transport and colicin E1; Helgerson SL et al.; It is of interest to inquire whether agents that uncouple or deenergize membranes cause concomitant structural changes . The agents considered here are the uncoupler carbonyl cyanide-p-trifluoromethoxyphenylhydrazone and the bacteriocidal protein colicin E1, agents for which there is some precedent for believing that they interact with membranes . In intact E . coli ML 308-225 cells the inhibition of {14C}-PROLINE ACtive transport by FCCP increases with uncoupler concentration from approximately 20% at 2 muM to approximately 100% at 5 muM . The increase in the rotational relaxation time (rho) of the cell-bound fluorescent probe N-phenyl-1-naphthylamine (PhNap)1 and 8-anilino-1-naphthalene-sulfonate (ANS) under these conditions shows the same dependence on FCCP concentration . For cells treated with EDTA to remove part of the outer lipopolysaccharide layer, inhibition of proline transport and the increase in rho value of ANS show the same dependence on FCCP concentration with saturation at 0.3 muM . EDTA treatment causes a large increase in the binding and rotational relaxation time of PhNap, the latter quantity approaching a value obtained with purified inner membrane . Similar effects are produced in untreated cells by 5muM FCCP...

J Hyg Epidemiol Microbiol Immunol, 1976, 20(4), 450 - 6
Inducing effect of cortisone and insulin on the activity of beta-galactosidase in the E . coli strains K12; Boichenko MN et al.; Individual and combined effects of cortisone and insulin on the synthesis of beta-galactosidase in the strains E . coli K 12 200 PS/Flac and M-308 and the possiblity of cortisone uptake by the bacterial cell under different temperature conditions were investigated in their dynamics . When insulin and cortisone are applied simultaneously in doses showing individually the greatest stimulative effect on the synthesis of beat-galactosidase, no summation of the effect of the hormones occurs in the strain E . coli 200 PS/Flac in the presence of IPTG while in the strain E . coli ML-308 simultaneous application of insulin and cortisone induces a negligible increase in the activity of beta-galactosidase . Tests for the incorporation of {3H} cortisone into the strains E . coli 200 PS/Flac and ML-308 have shown that the hormone is taken up by the bacterial cell immediately after its addition to the incubation medium, reaching its maximum after 5 min of incubation and maintaining the same level in the subsequent 30 min . The incorporation of {3H} cortisone at a temperature of 37degrees C is markedly higher than at 4degrees C . Preliminary incubation of the cultures with unlabelled cortisone and insulin resulted in a decrease in the uptake of {3H} cortisone by the bacterial cell.

J Hyg Epidemiol Microbiol Immunol, 1976, 20(4), 443 - 9
Mutagenesis in the strains E . coli K-12 with different ability to genetic recombination; Pekhov AP et al.; Data on the role of recombination in spontaneous mutagenesis in E . coli K-12 are presented . On the basis of these data it can be presumed that such mutagenesis results from errors in spontaneous recombination . The study of the dependence of mutagenesis induced by mitomycin C, nitrosoguanidine and ethylmethanesulphonate has revealed that only mutagenesis induced by mitomycin C depends on the recombination ability of the cells . Mutagenesis induced by mitomyin C results from errors in the recombinative restoration of damages to DNA induced by this mutagen.

Pol J Pharmacol Pharm, 1976, 28(5), 429 - 35
Studies on antilipolytic activity of antipyretics . Part I . Influence of sodium salicylate, acetylsalicylic acid, phenazone, aminophenazone, and acetophenidin on lipolysis in fever induced by E . coli pyrogen; Matuszek M; The fever induced by E . coli pyrogen (LPS) is accompanied by a rise of FFA and glycerol level . All tested antipyretics inhibited both thermogenesis of lipolysis produced by LPS . These results suggest that the antipyretic effect of antipyretic drugs is not confined to their action on heat-dissipating mechanisms, but may also be exerted by a depression of lipid metabolism.

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