Escherichia coli

Mol Gen Genet, 1979 Sep, 175(2), 159 - 74
Physical characterisation of the "Rac prophage" in E . coli K12; Kaiser K et al.; We confirm the hypothesis of Low (1973) that many E . coli K12 strains contain a prophage (the Rac prophage) located a few minutes clockwise of the trp operon on the genetic map . We have used restriction endonucleases and 32P-labelled probes to construct a physical map of this prophage . Some E . coli K12 strains, including AB1157, have lost the entire prophage, apparently by a specific deletion . This is consistent with prophage excision by site-specific recombination . lambda reverse (lambda rev) phages (Zissler et al., 1971) are recombination proficient derivatives of phage lambda in which the phage recombination functions have been replaced by analogous functions (RecE) derived from the host chromosome (Gottesman et al., 1974; Gillen et al., 1977) . Our data support the origin of lambda rev plages by recombination between lambda and the Rac prophage following excision of the Rac prophage from the E . coli chromosome . Important experimental data are included in the Figure legends.

Mol Gen Genet, 1979 Sep, 175(2), 151 - 7
Location and characterisation of a new replication origin in the E . coli K12 chromosome; Diaz R et al.; A segment of DNA located in the region of the E . coli K12 chromosome previously identified by the Rac phenotype can function as a self-replicating plasmid . Evidence is presented that this plasmid, the oriJ plasmid, contains the origin of replication of a defective prophage postulated to be located in this chromosomal region by Low (1973) . The plasmid can only be maintained in strains in which this postulated prophage has been deleted . In strains which possess the prophage selection for plasmid maintenance permits the isolation of clones containing new deletions which we postulate are the result of prophage excision.

Gene, 1979 Sep, 7(1), 1 - 14
Preparation and characterization of large amounts of restriction fragments containing the E . coli lac control elements; Hardies SC et al.; Large quantities of pure DNA fragments (789, 203 and 95 bp in length) containing the Escherichia coli lac controlling elements (operator, promoter, CRP binding site) were prepared from appropriate recombinant plasmids . High pressure liquid chromatography on RPC-5 or preparative sucrose gradient centrifugation was used to fractionate the pVH51 vector from the inserts . The fragments had few, if any, nicks or depurinated sites, and the majority of the fragment ends were intact . Absorbance-temperature profiles on the fragments showed multiphasic transitions.

Z Naturforsch {C}, 1979 Sep-Oct, 34(9-10), 742 - 6
Inhibition of E . coli L-Asparaginase by reaction with 2,3-butanedione . Chemical modification of arginine and histidine residues; Petz D et al.; The inactivation of E . coli asparaginase by 2,3-butanedione studied with L-asparagine and diazooxonorvaline as substrates obeys pseudo first order kinetics . Activity losses are linear with respect to arginine and histidine modification, with complete inactivation being correlated with alteration of one arginine and one histidine per subunit . The rate of inactivation of the enzyme was reduced in the presence of competitive inhibitors like L-2-amino-2-carboxyethane-sulfonamide . Under comparable conditions 1,2-cyclo hexanedione does not affect the activity of L-asparaginase.

J Pharm Pharmacol, 1979 Sep, 31(9), 583 - 7
Haemodynamic effects of the carboxylic ionophore monensin when administered before and during shock induced by E . coli endotoxin; McCaig DJ et al.; The haemodynamic effects of the carboxylic ionophore monensin have been examined in cats anaesthetized with sodium pentobarbitone . Marked increases in left ventricular dP/dtmax (and dP/dt at fixed isovolumic pressures) and slight increases in cardiac output and stroke volume occurred, indicating increased myocardial contractility . Heart rate was unchanged but systemic arterial pressure was substantially increased . Satisfactory increases in contractility and arterial pressure were obtained when monensin was infused intravenously in a total dose of 0.25 mg kg-1 over 10 min . Larger doses, especially if rapidly injected, resulted in very marked increases in myocardial contractility leading eventually to cardiac failure . The haemodynamic effects of monensin were markedly reduced during shock induced by E . coli endotoxin and there was unfortunately no evidence to suggest that this extremely potent compound might be potentially beneficial in this form of profound cardiovascular shock.

Nucleic Acids Res, 1979 Aug 24, 6(12), 3891 - 909
Polynucleotide-protein interactions in the translation system . Identification of proteins interacting with tRNA in the A- and P-sites of E . coli ribosomes; Abdurashidova GG et al.; Ultraviolet irradiation (lambda = 254 nm) of ternary complexes of E . coli 70 S ribosomes with poly(U) and either Phe-tRNAPhe (in the A-site) or NAcPhe-tRNAPhe (in the P-site) effectively induces covalent linking of tRNA with a limited number of ribosomal proteins . The data obtained indicate that in both sites tRNA is in contact with proteins of both 30 S and 50 S subunits (S5, S7, S9, S10, L2, L6 and L16 proteins in the A-site and S7, S9, S11, L2, L4, L7/L12 and L27 proteins in the P-site) . Similar sets of proteins are in contact with total aminoacyl-tRNA and N-acetylaminoacyl-tRNA . However, here no contacts of tRNA in the P-site with the S7 and L25/S17 proteins were revealed, whereas in the A-site total aminoacyl-tRNA contacts L7/L12 . Proteins S9, L2 and, probably, S7 and L7/L12 are common to both sites.

Biokhimiia, 1979 Aug, 44(8), 1521 - 3
{Selective inhibition of ribosomal RNA synthesis by rifampicin in E . coli cells}; Kliachko EV et al.; Under partial inhibition of total RNA synthesis by rifampicin the formation of beta- and beta'-subunits of RNA polymerase is stimulated and the rRNA synthesis is selectively repressed . The differential rate of synthesis of the beta- and beta'-subunits increases from 1,15% up to 2,88% in the presence of 30 micrograms rifampicin per ml . Simultaneously the differential rate of rRNA synthesis decreases from 41% down to 10% . The degree of inhibition of rRNA synthesis by rifampicin depends on the cell growth rate.

Biokhimiia, 1979 Aug, 44(8), 1512 - 20
{Phospholipids of E . coli and activity of alkaline phosphatase}; Nesmeianova MA et al.; The effects of liposomes prepared from the E . coli lipids on the activity of soluble alkaline phosphatase and on the complementation reaction between its subunits were studied . It was shown that the liposomes nonspecifically catalyze the dimerization of the enzyme subunits without changing the dimer activity . The effects of phospholipases A2 and C on the activity of membrane-bound alkaline phosphatase were studied . An interrelationship was found between the level of hydrolysis of membrane phosphatidyl glycerol (PG) by these enzymes and the changes in the activity of membrane-bound alkaline phosphatase . It was also shown that PG is less accessible to the effects of phospholipases in the cells with derepressed biosynthesis of alkaline phosphatase . It is assumed that the membrane PG interacts with the membrane-bound alkaline phosphatase during its translocation into the periplasm.

Mol Gen Genet, 1979 Aug, 175(1), 77 - 87
Characterization of lambdapolA transducing phages; effective expression of the E . coli polA gene; Murray NE et al.; lambdapolA phages carrying the polA gene in either orientation were isolated and characterised by genetic tests and by assay of the polA gene product after infection of E . coli or induction of lysogens . Lytic infection gave consistently better amplification of DNA polymerase I than that obtained by induction of a lysogen . Optimal amplification of DNA polymerase I was not achieved from the PL promoter of cro-phages, but some advantages accrued when the polA gene was oriented for transcription from the PL promoter of a cro+ phage . lambdapolA phages in which the polA allele was from E . coli strain C600 provided better amplification than phages with the polA allele from E . coli ED8659 . Induction of a lambdapolA1 cI857 Qam Sam prophage gave levels of DNA polymerase I approaching 100 times that found in the non-lysogenic Pol+ host . Genetics studies with the lambdapolA phages confirmed the previously postulated orientation of the polA gene within the E . coli genome.

Mol Gen Genet, 1979 Jul 24, 174(3), 281 - 6
Different specific activities of the monomeric and oligomeric forms of plasmid DNA in transformation of B . subtilis and E . coli; Mottes M et al.; (1) The low residual transforming activity in preparations of monomeric, supercoiled, circular (CCC) forms of the plasmids pC194 and pHV14 could be attributed to the presence in such isolates of a small number of contaminating multimeric molecules . (2) E . coli derived preparations of pHV14, as in vitro recombinant plasmid capable of replication in both E . coli and B . subtilis, contain oligomeric forms of plasmid DNA in addition to the prevalent monomeric CCC form . The specific transforming activity of pHV14 DNA for E . coli is independent of the degree of oligomerization, whereas in transformation of B . subtilis the specific activity of the purified monomeric CCC molecules is at least four orders of magnitude less than that of the unfractionated preparation . (3) Oligomerization of linearized pHV14 DNA by T4 ligase results in a substantial increase of specific transforming activity when assayed with B . subtilis and causes a decrease when used to transform E . coli.

Mol Gen Genet, 1979 Jul 2, 174(1), 53 - 8
Assembly of ribosomal subunits affected in a ribosomal mutant of E . coli having an altered L22 protein; Pardo D et al.; In this article we describe some in vivo properties of a coldsensitive ribosomal mutant from Escherichia coli . The mutation affects the rplV gene which is the structural gene of ribosomal protein L22 . Our work shows that at 22 degrees C, the biosynthesis of both ribosomal subunits and the maturation processing of 15S and 23S ribosomal RNA are impaired . Integration of our results in a general model of in vivo ribosomal assembly in E . coli is presented.

Biophys Chem, 1979 Jul, 10(1), 47 - 54
Comparison of van 't Hoff and calorimetrically determined enthalpies of binding of N-phosphonacetyl-L-aspartate to E . coli aspartate transcarbamylase; Hofmann GE et al.; A comparison has been made of the values obtained by direct calorimetric measurements and van 't Hoff analysis, under similar conditions, for the enthalpy of binding of the bisubstrate analog N-phosphonacetyl-L-aspartate (PALA) to E . coli aspartate transcarbamylase and its catalytic subunit . In the case of the catalytic subunit, data were obtained at both saturating and non-saturating concentrations of L-Asp, and at two ionic strengths . Despite a 1000-fold difference in protein concentrations, and the obligatory omission of carbamyl phosphate in the calorimetric experiments, the values obtained by the two methods are shown to agree to within 15% when appropriate corrections are made . These results suggest that subunit dissociation is not a significant factor at the low protein concentrations used in the van 't Hoff analysis, and, conversely, that aggregation of the protein is negligible at the high protein concentrations used in the calorimetric experiments . They also imply that, at pH 8.3, the enthalpic difference between the two conformational states of the enzyme which exist in the presence and absence of substrates is less than 2.5 kcal/mol . In addition, the trends in the three sets of data for the catalytic subunit indicate that ionic bonds are involved in binding PALA to the active site, and that non-productive binding by L-Asp is negligible under these experimental conditions.

Vopr Med Khim, 1979 Jul-Aug, 25(4), 395 - 7
{Detection of plasmids in the cells of E . coli CK}; Nikol'skaia II et al.; Superspiralized coiled plasmide DNA were found in cells E . coli CK . One of plasmides pEco CK-1 had a size 21.2 micron that corresponded to molecular mass 43.7 megadaltons, another plasmide pEco CK-2 with the size 14.2 micron had a molecular weight 29.2 megadaltons . Effective restriction was observed in cross titration using phage PBV-I.CK for E . coli strains carrying R II plasmide and phage PBV-I.R II for E . coli CK cells . The data obtained suggest that the Eco CK type with DNA of host specificity is distinct from hsp II type due to presence of R II and N-15 plasmides.

Antibiotiki, 1979 Jul, 24(7), 516 - 20
{Effect of low doses of chloramphenicol on ribosomal precursor formation in E . coli cells}; Drobyshev VI; RNA synthesized in the cells of E . coli CP 78 (rel+) in the presence of chloramphenicol low concentrations (5 microgram/ml) was found in 30S and 50S subunits and monosomes . A significant part of it was alotted to ribonucleoproteid or chloramphenicol particles . The protein content of ribonucleoproteid amounted to 22-25% and the content of RNA in it was equal to 78-75%.

Dig Dis Sci, 1979 Jul, 24(7), 509 - 13
Differences in intrahepatic portal-systemic shunting in alcoholic and nonalcoholic liver disease as assessed by liver scan, portal pressure, and E . coli antibodies; Triger DR et al.; The interrelationship among portal vein pressure, 99mTc sulfur colloid liver/spleen scan abnormality, and serum E . coli antibody titers has been examined in 33 patients with alcoholic liver disease (ALD) and compared with 24 patients with liver disease not related to alcohol (non-ALD) . A correlation between portal vein pressure and liver scan abnormality is seen in both groups, but for a given degree of portal hypertension there is a much greater redistribution of sulfur colloid in the ALD group (P less than 0.01) . E . coli antibody titers are significantly higher in the ALD patients compared with the non-ALD patients (P less than 0.02), and they show a positive correlation with scan abnormality but not with portal vein pressure . It is suggested that the differences in scan appearance and E . coli antibody titers in these two groups of liver disease patients may be related to differences in intrahepatic shunting.

Biokhimiia, 1979 Jul, 44(7), 1212 - 7
{Exogenous orthophosphate regulation of ATPase activity of E . coli cells}; Nesmeianova MA et al.; The effect of exogenous orthophosphate and mutations in genes, regulating the Pi transport system, on the ATPase activity of E . coli subcellular fractions was studied . It was shown that the orthophosphate starvation resulted in the cessation of the increase in the ATPase activity of membranes and was accompanied by the increase in the analogous activity of a soluble fraction at the expense of the derepression of alkaline phosphatase possessing this activity . The disturbance, resulted from the mutation of protein components participating in the specific binding and transport of orthophosphate, changed the ATPase activity of subcellular fractions: increased the ATPase activity of soluble fraction (independently of the presence of orthophosphate in medium), did not affect significantly the activity of membrane--bound ATPase in the presence of orthophosphate and decreased this activity in the absence of orthophosphate . The data obtained point to the fact that components, binding exogenous orthophosphate and transporting it into a cell, affect the rigidity of the ATPase bound E . coli cytoplasmic membrane . Mutations resulting in the defect in these components relax this bound and lead to the detection of ATPase proper in the periplasm.

Biull Eksp Biol Med, 1979 Jul, 88(7), 65 - 8
{Dimethylaminochalcone, an indicator of the structural changes in the cellular envelop of E . coli under the action of Ca2+ cations and tris buffer}; Sabel'nikov AG et al.; An attempt was made to detect possible structural changes in E . coli cell envelope induced by Ca2+ treatment with the help of an uncharged fluorescent probe 4-dimethylaminochalcon (DMC) . The effects of the treatment with tris buffer (0.01 M) at 0 degrees C and other agents (Mg2+ and EDTA) were also studied for the purpose of comparison . It is shown that Ca2+ treatment of E . coli cells results in structural changes in the cell envelope surface, whick differ from those induced by tris-buffer at 0 degrees C, Mg2+ and EDTA . DMC can be used successfully as a suitable probe for monitoring structural changes in biomembranes.

Nucleic Acids Res, 1979 Jun 25, 6(8), 2919 - 28
Blue dextran Sepharose chromatography of the tryptophanyl-tRNA synthetase of E . coli: a potential application for the purification of the enzyme; Drocourt JL et al.; E . coli tryptophanyl-tRNA synthetase can form a complex with Blue-dextran Sepharose, in the presence or in the absence of Mg++ . In its absence, the complex is dissociated by either ATP or cognate tRNATrp . However, in the presence of Mg++, only tRNATrp can dissociate the complex whereas ATP has no effect . E . coli total tRNA or tRNAMet, at the same concentration, cannot displace the synthetase from the complex . It is suggested that the Blue-dextran binds to the synthetase through its tRNA binding domain . This hypothesis is supported by previous findings with polynucleotide phosphorylase showing that Blue-dextran Sepharose can be used in affinity chromatography to recognize a polynucleotide binding site of the protein . The selective elution by its cognate tRNA of Trp-tRNA synthetase bound to Blue-dextran Sepharose provides a rapid and efficient purification of the enzyme . Examples of other synthetases and nucleotidyl transferases are also discussed.

Nucleic Acids Res, 1979 Jun 11, 6(7), 2637 - 46
Studies on the RNA and protein binding sites of the E . coli ribosomal protein L10; Pettersson I; We have used modification of specific amino acid residues in the E . coli ribosomal protein L10 as a tool to study its interactions with another ribosomal protein, L7/L12, as well as with ribosomal core particles and with 23S RNA . The ribosome and RNA binding capability of L10 was found to be inhibited by modification of one more of its arginine residues . This treatment does not affect the ability of L10 to bind four molecules of L7/L12 in a L7/L12-L10 complex . Our results support the view that L10's role in promoting the L7/L12-ribosome association is due primarily to its ability to bind to both 23S RNA and L7/L12 simultaneously.

Nucleic Acids Res, 1979 Jun 11, 6(7), 2545 - 60
A study on the unprimed poly (dA-dT) synthesis catalyzed by preparations of E . coli DNA polymerase I; Nazarenko IA et al.; Evidence was obtained indicating that the initiation of poly (dA-dT) de novo synthesis is provided by deoxynucleoside diphosphate: oligonucleotide deoxynucleotidyl transferase (dNDP-transferase present in preparations of E . coli DNA polymerase I and capable of catalyzing the unprimed polymerization of dNDP . dNDP-transferase synthesyzes short oligonucleotides which form template-primer complexes repeatedly replicated by DNA polymerase I . This conclusion was based on the following observations: the abolition of the lag period of poly (dA-dT) synthesis by preincubation of DNA-polymerase I preparations with dADP and dTDP; the presence of oligo (dA-dT) among the preincubation products; the suppressive effect of dithiothreitol and N-ethylmaleimide (inhibitors of dNDP-transferase) on the de novo, but not on the primed synthesis of poly (dA-dT), catalyzed by preparations of DNA-polymerase I.

Mol Gen Genet, 1979 Jun 7, 173(2), 135 - 44
Synthesis and degradation of lac mRNA in E . coli depleted of 30S ribosomal subunits; Har-El R et al.; Escherichia coli was depleted of active ribosomes by a thermal shock at 47 degrees C which quantitatively destroyed the 30S ribosomal subunits . During recovery, RNA is synthesized while protein synthesis resumes only after about 90 minutes . It is shown that lac mRNA is synthesized in the complete absence of ribosomal activity and hence RNA synthesis is not coupled to protein synthesis . Transcription time and average transcript length were slightly less than in untreated cells . lac mRNA was degraded much more slowly in bacteria depleted of ribosomes . In E . coli W both functional half life (T 1/2 = 28 min vs . 2.25 in untreated cells) and chemical stability . The analysis of rna and pnp mutants showed that polynucleotide phosphorylase is involved in lac mRNA degradation in heat treated cells but that RNase I is not . The functional T 1/2 was increased in pnp mutants and was 95 min during the recovery period . The rate of chemical decay is so slow that the half-life cannot be accurately determined.

Mol Gen Genet, 1979 Jun 7, 173(2), 127 - 34
Relief of polarity in E . coli depleted of 30S ribosomal subunits; Cohen T et al.; Escherichia coli was depleted of ribosomes by a thermal shock at 47 degrees C which quantitatively destroyed the 30S ribosomal subunits . During recovery in minimal medium at 30 degrees C RNA is synthesized while protein synthesis resumes only after about 90 min . It is shown that lac mRNA is synthesized in the complete absence of ribosomal activity and hence RNA synthesis is not coupled to protein synthesis . Lac mRNA from a series of lac nonsense mutants was examined in both heated and untreated cells . It was found that the polar effect of nonsense mutation is relieved in the absence of ribosomes and that this relief is due to the synthesis of larger mRNA molecules . Since Rho remained active in thermally treated cells, premature termination at secondary signals within the lac operon must also depend on the presence of active ribosomes.

Rev Bras Pesqui Med Biol, 1979 Jun, 12(2-3), 117 - 22
Liquid holding recovery in E . coli K12 . I - Substances released during buffer holding; Aragao BR et al.; It is known that the incubation, in a buffer, of UV-irradiated E . coli cells results in viability increase, this phenomenon had been called liquid holding recovery (LHR) . We have studied the cellular constituents release during LHR and verified that releasing rate is dose-dependent . LHR was also observed after nitrogen-mustard treatment and it is not blocked by caffeine . So, we suggest that LHR expression is not always a rec-gene dependent function and, probably, the survival increase could be explained by (a) DNA-repair, (b) reversible membrane damage and (c) cellular multiplication.

Rev Bras Pesqui Med Biol, 1979 Jun, 12(2-3), 111 - 6
Some repair effectiveness coefficients as indicators of E . coli UV-resistance; Pelico JV et al.; Mathematical studies of E . coli survival curves to UV (254 nm) lead to the definition of a photoresistance parameter - the "mean survival dose" (MSD) - to compare radiation resistances of genetically related bacterial strains . Based on this MSD-parameter some repair coefficients were proposed as indicators of the relative effectiveness with which every repair system recovers radiation lesions in cells . The theoretical values calculated for the proposed coefficients are in agreement with those which were obtained from experimental data presented in the literature.

Int J Radiat Biol Relat Stud Phys Chem Med, 1979 Jun, 35(6), 539 - 48
Influence of unsaturated fatty acids, membrane fluidity and oxygenation on the survival of an E . coli fatty acid auxotroph following gamma-irradiation; Yatvin MB et al.; Escherichia coli K1060, a fatty acid auxotroph unable to either synthesize or degrade unsaturated fatty acids (uFAs), was used to study the effect of membrane fluidity on survival after exposure to ionizing radiation . Using this strain of E . coli, significant alterations in the fatty acid composition of the membrane have been produced and verified by gas chromatography . Linolenic, oleic, elaidic and palmitelaidic acids were the uFAs used . Survival above the transition temperature (Tt) (liquid crystal in equilibrium gel) was comparable for these fatty-acid-supplemented membranes after exposure to gamma-irradiation, whereas gamma-irradiation below Tt resulted ina significant decrease in survival . An oxygen enhancement effect was observed for each experimental condition employed.

Br J Cancer, 1979 Jun, 39(6), 755 - 60
Radiosensitization of E . coli B/r by the cytotoxic agent procarbazine: a hypoxic cell sensitizer preferentially toxic to aerobic cells and easily oxidized; Roberts PB; Procarbazine has been shown to be a hypoxic cell sensitizer of moderate ability in E . coli B/r, with an achievable enhancement ratio of 1.4 at subtoxic concentrations . The drug appears to act in a manner similar to the expected with the electron-affinic radiosensitizers . However, procarbazine and the electron-affinic sensitizers differ in two important respects . Unlike the electron-affinic sensitizers, procarbazine is not easily reduced, but is easily oxidized . It is more toxic to aerobic than to hypoxic cells . At the drug dosages in present clinical use, procarbazine is likely to be only a weak radiosensitizer . The possible implications of the data for the further development of a new class of sensitizers and combination therapy are discussed.

Cell, 1979 Jun, 17(2), 265 - 74
E . coli DNA binding protein HU forms nucleosomelike structure with circular double-stranded DNA; Rouviere-Yaniv J et al.; The incubation of the E coli DNA binding protein HU with relaxed circular SV40 DNA in the presence of pure nicking-closing enzyme introduces up to 18 negative superhelical turns in the DNA molecules as measured by agarose gel electrophoresis . The maximal density of supercoiling is obtained at a HU-DNA mass ratio of 1 . Reconstituted DNA-HU complexes prefixed with glutaraldehyde appear as condensed circular structures having an average of 14 "beads" per circular SV40 DNA molecule, with a "bead" diameter of 180 +/- 23 A . The circular SV40 DNA is condensed by a ratio of 2.0-2.5 relative to naked DNA . This is similar to the ratio (2.4) measured for chromatin formed by reassociation of relaxed SV40 DNA with the four core histones.

Biokhimiia, 1979 Jun, 44(6), 1101 - 9
{Transhydrogenase as an additional site of energy accumulation in the E . coli respiratory chain}; Chetkauskaite AV et al.; NAD+ reduction catalyzed by transhydrogenase (EC 1.6.1.1) from E . coli membrane particles at the expense of NADPH oxidation is coupled with phenyldicarbaundecaborate (PCB-) absorption by the particles . This process is inhibited by oxidative phosphorylation protonophorous uncouplers and by equilibration of concentrations of the substrates and products of the transhydrogenase reaction . Elimination of the water-soluble part of membrane ATPase results in the inhibition of PCB- absorption at the expense of the transhydrogenase reaction energy . Treatment of the particles by dicyclohexyl carbodiimide increases the transhydrogenase-coupled absorption of PCB- . The transhydrogenase-induced increase of pPCB in the suspension of particles is directly correlated with the ratio of ({NADPH}.{NAD+})/({NADP+}.{NADH}) . When this value is equal to 1, no energy-dependent increase of pPCB was observed . NADP+ reduction at the expense of NADH oxidation leads to a decrease in the amount of PCB- absorbed by the particles at the expense of ATP hydrolysis energy . The experimental data suggest that NADPH oxidation in the course of the transhydrogenase reaction is coupled with the formation of a membrane potential with a positive charge localized inside the particles.

Mol Gen Genet, 1979 May 23, 173(1), 51 - 9
Inactivation of E . coli RNA polymerase by polyriboinosinic acid: heterogeneity of RS complexes; DeLorbe WJ et al.; Polyriboinosinic acid (poly I) inhibits initiation of transcription by binary complexes formed between Adenovirus 2 DNA and E . coli RNA polymerase holoenzyme . In the presence of poly I, just as in the presence of rifampicin, initiation of transcription exhibits a sigmoidal dependence on the temperature at which the binary complexes are formed . This indicates that I (closed) complexes between Ad 2 DNA and RNA polymerase are rapidly inactivated by poly I, but that RS (open) complexes are relatively resistant . However, even among the RS complexes, at least two classes can be distinguished on the basis of the degree to which they are resistant to poly I: RS-1 complexes are somewhat sensitive to poly I (half-time of inactivation approximately 10 min) while RS-2 complexes are almost completely resistant to the inhibitor (half-time of inactivation approximately 10 h) . For both types of RS complex, the degree of sensitivity to poly I is ionic strength-dependent.

Mol Gen Genet, 1979 May 4, 172(2), 171 - 8
Isolation and restriction mapping of plasmids containing ribosomal DNA sequences from the rrn B cistron of E . coli; Palmer ML et al.; Recombinant plasmids containing the entire 16S RNA gene from the rrn B cistron of E . coli inserted in Col E1 and pBR322 plasmid vectors have been constructed . These plasmids have been mapped using several restriction endonucleases as well as by DNA-RNA hybridization . These maps reveal previously undetected restriction sites in the rrn B cistron and in Col E1 plasmid DNA.

Mutat Res, 1979 May, 60(3), 263 - 70
Relative effectiveness of the 300--320 NM spectral region on sunlight for the production of primary lethal damage in E . coli cells; Harm W; Cell inactivation by sunlight exposure has been studied in E . coli CSR 603 (uvrA recA phr), a K12 derivative which is deficient in all known repair systems . Under suitable conditions, unfiltered sunlight inactivates these cells to 10(-3) survival within 30 sec . The effects of unfiltered sunlight have been compared with those of sunlight filtered through 1-cm layers of aqueous caffeine solutions ranging in concentration from 1 to 20 mg/ml . In the wavelength region of solar emission below 320 nm, which is most critical for DNA damage, the transmission of these liquid filters changes from 10 to 90% within 8-nm intervals . Thus our results permit minimum estimates for the fraction of lethal lesions produced by the solar spectrum below certain wavelenghts . In an experiment analyzed in this manner more than 80% of primary lethal lesions are caused by wavelengths less than 321 nm, and more than 50% by wavelengths less than 306 nm, while the contribution of wavelengths greater than 380 nm to primary lethal damage is below 1%.

Biophys Chem, 1979 May, 9(4), 405 - 12
Relaxation kinetics of E . coli ribosomes: evidence for the reaction of 30S . IF3 complex with 50S ribosomal subunits; Chaires JB et al.; Addition of initiation factor IF3 to solutions of E . coli ribosomes dramatically alters their behavior in pressure-jump relaxation kinetic experiments in which 90 degrees light-scattering is used to monitor the macromolecular reaction . The effect of IF3 on relaxation processes attributed to "tight" couples is strongly dependent on the Mg2+ concentration . At 2.5 mM Mg2+, addition of 1 molar equivalent of IF3 decreases the relaxation amplitude by a factor of 3 relative to ribosome solutions without IF3 . However, at 5.0 mM Mg2+, addition of 1 molar equivalent of IF3 produces a marked increase in the relaxation amplitude, by a factor of 2-8 fold relative to ribosomes in the absence of IF3 . IF3 has no effect on the relaxation process attributed to "loose" couples at 10 mM Mg2+ . While we are unable to propose a precise mechanism for IF3 action with the data on hand, our results require that the 30S . IF3 complex either reacts with the 50S subunit, forming a 70S . IF3 intermediate, or acts as a pool of reactive 30S subunit . Further kinetic evidence is required to distinguish between these possible pathways.

Mol Biol (Mosk), 1979 May-Jun, 13(3), 681 - 9
{Role of RNA-polymerase in gene activity regulation of E . coli RNA-polymerase mutants with a pleiotropic effect . I . Physiological and biochemical studies}; Kamzolova SG et al.; Four Rifr-mutants of E . coli B/r (rpo B401, rpo B402, rpo B403, rpo B409) which differ from the wild strain in one or more phenotypic properties besides rifampicin resistance were obtained . Transfer of the mutant Rifr-alleles into the parent strain gives the latter all the properties of the mutant . This indicates that the new properties are due to the pleiotropic effect of Rifr-mutations . Biochemical studies of the properties of RNA-polymerases from the mutants and the parent showed that some new properties of the mutants could not be explained by the appearance of analogous properties in the mutant RNA-polymerase itself . They seem to be caused by alteration in functional activity of the mutant enzyme, particulary, alteration of its control properties during transcription . The function of the beta-subunit in genetic transcription is discussed.

Cell, 1979 May, 17(1), 211 - 24
Identification of initiation sites for the in vitro transcription of rRNA operons rrnE and rrnA in E . coli; Gilbert SF et al.; The transcription initiation sites of E . coli rRNA operons were determined using various DNA fragments derived from transducing phage lambda metA20 carrying rrnE and from hybrid plasmid pLC19-3 carrying rrnA . In vitro transcription products were analyzed for their 5' end sequences and their oligonucleotide compositions . The results are in full agreement with the nuceotide sequences of the DNA templates described in an accompanying paper (de Boer, Gilbert and Nomura, 1979) and allow us to make the following conclusions . First, there are two transcription, start sites on each of the rRNA operons; they are 109 bp apart in the case of rrnE and 117 +/- 1 bp aprart in rrnA . Second, the first start site is 283 bp upstream from the m16S rRNA coding region in the case of rrnE, while is 291 bp upstream in rrnA . Initiation starts with ATP in both cases . Finally, the second start sites are 174 and 174 +/- 1 bp from the m16S rRNA genes in rrnE and rrnA, respectively . Initiation starts with CTP in both cases . We have also shown that in the present in vitro transcription system, guanosine tetraphosphate (ppGpp) inhibits the synthesis of full-sized RNAs from both start sites in each rRNA operon.

Cell, 1979 May, 17(1), 201 - 9
DNA sequences of promoter regions for rRNA operons rrnE and rrnA in E . coli; de Boer HA et al.; The nucleotide sequences have been determined for the promoter regions of two ribosomal RNA operons, rrnA and rrnE, in E . coli . The sequences cover the two in vitro transcription start sites identified for each operon (Gilbert, der Boer and Nomura, 1979) . The first two start sites are 283 and 291 bp preceding the mature 16S rRNA (m16S rNA) coding regions for rrnE and rrnA, respectively; the second start sites are 174 and 174 +/- 1 bp preceding the m16S rRNA coding regions for rrnE and rrnA, respectively . Each of these start sites has an identifiable "Pribnow box" sequence 6-7 bp upstream from the start site . The nucleotide sequences of the two operons have nearly complete homology from the m16S rRNA coding regions to positions 145 bp upstream from those regions, and at the regions surrounding the Pribnow boxes preceding the first start sites . The DNA sequences indicate that the RNAs transcribed from the first start sites of rrnE and rrnA are quite different in their first 150 nucleotides . These heterogeneous regions, however, precede the RNAse III cleavage sites (deduced previously by Young and Steitz, 1978), and the "precursor 16S rRNA" molecules are largely homogeneous . The nucleotide sequences of the promoter regions of the two rRNA operons are also compared with those or rrnD and rrnX, determined by Young and Steitz (1979), and some common features are discussed.

Cell, 1979 May, 17(1), 175 - 84
Site-specific cleavage of DNA by E . coli DNA gyrase; Morrison A et al.; E . coli DNA gyrase, which catalyzes the supercoiling of DNA, cleaves DNA site-specifically when oxolinic acid and sodium dodecylsulfate are added to the reaction . We studied the structure of the gyrasecleaved DNA because of its implications for the reaction mechanism and biological role of gyrase . Gyrase made a staggered cut, creating DNA termini with a free 3' hydroxyl and a 5' extension that provided a template primer for DNA polymerase . The cleaved DNA was resistant to labeling with T4 polynucleotide kinase even after treatment with proteinase K . Thus the denatured enzyme that remains attached to cleaved DNA is covalently bonded to both 5' terminal extensions . The 5' extensions of many gyrase cleavage fragments from phi X174, SV40 and Col E1 DNA were partially sequenced using repair with E . coli DNA polymerase I . No unique sequence existed within the cohesive ends, but G was the predominant first base incorporated by DNA polymerase I . The cohesive and sequences of four gyrase sites were determined, and they demonstrated a four base 5' extension . The dinucleotide TG, straddling the gyrase cut on one DNA strand, provided the only common bases within a 100 bp region surrounding the cleavage sites . Analysis of other cleavage fragments showed that cutting between a TG doublet is common to most, or all, gyrase cleavages . Other bases common to some of the sequenced sites were clustered nonrandomly around the TG doublet, and may be variable components of the cleavage sequence . This diverse recognition sequence with common elements is a pattern shared with several other specific nucleic acid-protein interactions.

Biull Eksp Biol Med, 1979 May, 87(5), 466 - 8
{Effect of formaldehyde and its aminomethylol derivatives on E . coli strains with various defects of the DNA repair systems}; Mitsevich EV et al.; It was shown that aminomethylol compounds formed during reaction of formaldehyde with amino acids and formaldehyde as well exert a pronounced lethal action on E . coli strains with various defects of the DNA repair systems . The correlation between the extent of the DNA depurination caused by in vitro action of diverse aminomethylol derivatives and the inactivation of bacteria by these derivatives is revealed . The data obtained suggest that the inactivating effect of formaldehyde and its aminomethylol derivatives seems likely to be due to the formation of depurinized groups in bacterial DNA rather than to dimerization of purine bases.

Cell, 1979 May, 17(1), 225 - 34
Tandem promoters direct E . coli ribosomal RNA synthesis; Young RA et al.; To determine the special feature of ribosomal RNA promoters that might account for the highly efficient and regulated synthesis of rRNA in E . coli, we have analyzed the beginnings of two ribosomal RNA operons, rrnD and rrnX . DNA sequences for 425 bp preceding those specifying mature 16s rRNA are reported . In vitro transcription of restriction endonuclease fragments containing this region from either operon reveals the presence of two promoters about 110 nucleotides apart; they are denoted P1 and P2 . RNA synthesis from P1 is initiated with GTP at position -284 (relative to 16s sequences) in rrnD and with ATP at position -285 in rrnX . At P2, the RNA starts with CTP primarily at position-176 in both operons . The DNA sequences of the two operons are identical for 231 bp preceding the 16s rDNA (including a substantial region around P2); they then diverge almost completely, except for a notable 18 bp homology just preceding the transcription start site for P1 . Certain sequences implicated in the recognition of promoters by E . coli RNA polymerase are clearly identifiable in both P1 and P2; other features include an extended region preceding P1 which is strikingly rich in AT base pairs . Possible mechansims by which these tandem promoters contribute to the high frequency of rRNA transcription and to the differential expression of the E . coli rrn operons are discussed.

Zentralbl Bakteriol {Orig A}, 1979 Apr, 243(2-3), 197 - 206
{Enteritis due to Escherichia coli O142 K86 H34 in a ward of premature infants . With a discussion on the problem of pathogenicity of "enteropathogenic serogroups of E . coli" (author's transl)}; Bockemuhl J et al.; E . coli O142 K86 H34 has been isolated from stool specimens of five babies in a ward of premature infants . Diarrheal stools were observed in two of them; one infant temporarily failed to gain weight, and the other developed a temporary loss of weight . Smooth stools observed in the third baby as well as asymptomatic infections in two others did not affect their normal development . The outbreak lasted 15 days; the source of infection and the mode of transmission remained unknown . The pathogenesis and importance of human diarrheal disease caused by E . coli is reviewed . Enteritis of adults and children due to enteroinvasive (EIEC) and enterotoxigenic (ETEC) strains is described . The etiological role of so-called "enteropathogenic E . coli" (EPEC), rejected increasingly during the past decade, has been demonstrated again in recent studies . Routine search for EPEC is suggested in cases of infantile enteritis in hospitals and other institutions.

Nucleic Acids Res, 1979 Apr, 6(4), 1631 - 8
The binding of tyrosinyl-5'-AMP to tyrosyl-tRNA synthetase (E.coli); Grosse F et al.; The binding between tyrosyl-tRNA synthetase (E.coli) and the alkylanalogue of the aminoacyladenylate, tyrosinyl-5'-AMP, has been investigated by fluorescence titrations and rapid mixing experiments . Tyrosyl-tRNA synthetase has two equivalent and independent binding sites for tyrosinyl-5'-AMP . The intrinsic binding constant is 4 x 10(7)M-1 . The binding sites for tRNATyr and tyrosinyl-5'-AMP are independent of each other, the anticooperative mode of tRNA binding being preserved in the presence of tyrosinyl-5-AMP.

Acta Pathol Microbiol Scand {C}, 1979 Apr, 87C(2), 99 - 105
Uptake of non-opsonized E . coli by unstimulated mouse peritoneal macrophages; Rollag H; A method is described for the study of phagocytosis of 32P-labelled, non-opsonized, viable E . coli by mouse peritoneal macrophages . Factors influencing the uptake, such as medium, number of bacteria and time of phagocytosis, were standardized . The kinetics of the uptake were studied by visual counting of bacteria and by measuring the distribution of radioactive labelling . The uptake of 32P by the macrophages is well correlated to the number of bacteria phagocytized . The amount of phagocytosis depends on the bacterial density of the medium and the time of phagocytosis . When the medium contains more than 10(9) bacteria per ml, the maximum phagocytic capacity is reached after 90 minutes.

Biull Eksp Biol Med, 1979 Apr, 87(4), 328 - 30
{Electron microscopic study of conjugative plasmids from serologically typed E . coli AP1}; Kaliuzhnaia AP et al.; The plasmid DNAs isolated from E . coli AP1 were studied by electron microscopy . Two plasmid DNA forms (FB1-1 and FB1--2) with the mol wt of 35.9 +/- 0.5 x x 10(6) and 51.5 +/- 0.6 x 10(6) daltons, respectively, were revealed.

Mol Gen Genet, 1979 Mar 5, 170(3), 299 - 308
The structure of the DNA containing the E . coli tRNATry gene; Yarus M et al.; Using the pMB9 recombinant plasmid pMY3, which contains a functional gene for the tRNATry mutant Su+7, the EcoRI fragment containing the tRNATry gene is mapped and oriented with respect to the HindIII site in the tetracycline region of pMB9 . Complete HpaII and HaeIII maps of the EcoRI fragment are derived . The Su+7 tRNA gene is placed by hybridization to these fragments, and the tRNA gene is oriented by using the restriction sites for HinfI, TaqI, and HpaII in the tRNA gene itself . A tRNAAsp gene is shown to lie adjacent to tRNATry, and is also placed and oriented in the map . The RI fragment itself originates in a locus adjacent to, and transcribed in the same direction as, the ribosomal RNA genes of phi 80d3 . The implications of the structure of the cloned DNA for its previously measured regulatory and tRNA gene activities are discussed . In particular, the effect on the regulation of RNA synthesis is attributable to an E . coli DNA sequence, but cannot be due to the presence of a normal tRNA promoter on the plasmid.

Mol Gen Genet, 1979 Mar 5, 170(3), 291 - 8
Isolation and properties of a plasmid which expresses the E . coli Su+7 amber suppressor tRNA gene; Yarus M; The gene of the amber suppressor tRNA derived from tRNATry, Su+7, has been inserted into a col E1-derived vehicle by selecting for its expression . Despite selection for a suppressor phenotype, and the plasmid's stable presence at ca . 180 copies cell during balanced growth, the level mature tRNA maintained by the gene is less than that of the normal haploid tRNATry locus in the bacterial chromosome . Transfer RNA genes, both the plasmid Su+7 gene and chromosomal tRNA's are expressed during inhibition of protein synthesis . During, e.g . chloramphenicol inhibition, Su-7 and Su+7 tRNA can be elevated similarly in the plasmid-containing cell; Su+7 reaches levels of molecules/cell which ordinarily characterize a major tRNA . The recombinant plasmid, but not the cloning vehicle alone, has a more general effect on tRNA levels; accumulation of tRNA from three chromosomal tRNA loci including tRNATry, continues during extensive isoleucine limitation . The plasmid therefore contains a locus which probably alters the relaxed-stringent circuit, whose effect is disseminated to at least 3 widely separated loci.

Biokhimiia, 1979 Mar, 44(3), 570 - 2
{Modification of the alpha-subunit of phenylalanyl-tRNA synthetase from E . coli MRE-600 with N-chlorambucilyl-phenylalanyl-tRNA}; Lavrik OI et al.; L-Phenylalanyl-tRNA synthetase from E . coli MRE-600 (EC 6.1.1.20) was alkylated with N-chlorambucilyl-{14C} phenylalanyl-tRNA . After removal of the affinity reagent tRNA moiety bp alkaline hydrolysis of the ester bond between the N-chlorambucilyl-phenylalanyl residue and the 3'-end of tRNA, The enzyme was dissociated into subunits in the presence of SDS . Separation of the subunits was performed by SDS electrophoresis . The bulk of the radioactivity of the N-chlorambucilyl-{14C} phenylalanyl residue was found at the position of the alpha-subunit of the enzyme . The results obtained are consistent with a specific binding of the phenylalanyl-tRNA analog to the alpha-subunit of the enzyme followed by covalent binding of the N-chlorambucilyl-phenylalanyl moiety to the protein.

Biokhimiia, 1979 Mar, 44(3), 440 - 52
{Isolation and properties of DNA-cytosine-methyltransferase EcoRII and E . coli K12}; Bogdarina IG et al.; The methods of isolation and partial purification of two DNA-cytosine-methylases (DC-methylases) EcoRII and E . coli K12 are described . After chromatography on phosphocellulose the enzymes were purified 100-fold, the yield being 30% . Further purification of the enzymes was performed by sedimentation in a sucrose concentration gradient . Both enzymes have native molecular weights of 50,000; DC-methylase from E . coli K12 may simultaneously occur in the forms with molecular weights of 70,000, 90,000 and 110,000 . Both DC-methylases modify identical nucleotide sequences of DNA, have equal numbers (90) of methylation sites in phage lambda DNA and provide in vitro a complete protection of phage lambda DNA against restriction endonuclease EcoRII . DC-methylases E . Coli K12 and EcoRII differ in their chromatographic behaviour on phosphocellulose and capacity to form compexes with the cell DNA-adenine-methylase.

Cell, 1979 Mar, 16(3), 617 - 25
Mutants in transmission of chemotactic signals from two independent receptors of E . coli; Hazelbauer GL et al.; We have characterized chemotactic mutants of E . coli that appear to be defective in a common linkage of two independent receptors to the central chemotactic components . The mutants do not respond to gradients of ribose or galactose and thus are called trg (taxis to ribose and galactose), after Ordal and Adler (1974b) . These trg mutants are indistinguishable from their parent in tactic response to other attractants, swimming pattern, growth rates, and transport of ribose and galactose . The mutant cells contain the usual amounts of ribose and galactose receptors, and those proteins function normally in their other role, transport of their respective ligands . The mutations, generated by insertion of translocatable drug-resistance elements (transposons)8 are located near 31 min on the map of the E . coli chromosome, a locus far removed from the genes coding for the ribose and galactose receptors . Trg mutants do not resemble either specific receptor mutants or che mutants . The nature of the requirement for the trg product in the response to ribose and galactose is not defined, but evidence for interference of tactic signals from the ribose and galactose receptors (Strange and Koshland, 1976) supports the idea that the product functions directly in the transmission of tactic signals from the two receptors to the flagella.

Cell, 1979 Mar, 16(3), 523 - 34
Structure and organization of the two tRNATyr gene clusters on the E . coli chromosome; Rossi JJ et al.; The structure and organization of the gene clusters coding for the two tyrosine-accepting tRNA species (tRNA1Tyr and tRNA2Tyr) on the E . coli chromosome have been determined . The mature structural sequences of the two tRNATyr genes, located on opposite sides of the E . coli chromosome, differ by only 2 bp, but sequences surrounding these portions of the genes are very different . The genes coding for tRNA1Tyr (tyrT) comprise two mature structural sequences separated by a 200 bp "intergenic spacer." It is known that in transducing phage, the region adjoining the CCA end of the second mature structural sequence comprises a 178 bp repeated sequence which contains an in vitro, rho-dependent transcriptional termination site . We find that these potentially genetically unstable repeated sequences are present in the E . coli chromosome with the same organization as that determined from transducing phage analyses . The gene that codes for tRNA2Tyr (tyrU) is present in a single copy and is tightly clustered with three other tRNA genes . One of these genes (to be called thrU) encodes a previously undescribed tRNA (to be called tRNA4Thr) . The organization of this cluster on the E . coli chromosome is tRNA4Thr--8 bp--tRNA2Tyr--115 bp--tRNA2Gly--6 bp--tRNA3Thr . The importance of correlating structural analyses derived from specialized transducing phage with those determined for the chromosome itself is demonstrated by results which show that out of four independently isolated tRNATyr transducing phage, two carrying the tRNA1Tyr genes {phi80psu3+,- (Cambridge) and phi80sus2psu3+ (Kyoto)} and two carrying the tRNA2Tyr gene (lambdarifd 18 and lambdah80dglyTsu+36), only the first phage from each group has the same gene organization as that found in the E . coli chromosome.

Zentralbl Bakteriol {Orig A}, 1979 Mar, 243(1), 16 - 27
The lethal effect and the inhibition of colicin production by leucine on a phenylalanine requiring E . coli strain as a function of age and dilution of culture; Ben-Gurion R; The lethal effect caused by leucine on a phenylalanine requiring strain of Escherichia coli K-12 (7), was found to be strongly affected by the age of the culture . Early log cells were the least sensitive, while older cells became more sensitive to leucine . Another important factor affecting the sensitivity of this strain to leucine in liquid medium was the range of dilution of the culture . The age sensitive culture reacted to leucine only when its dilution was at a certain specific range . The sensitivity to leucine of a culture treated at the "right" age and at the proper dilution was proportional to the concentration of leucine . Colicine production was studied with cultures treated in various ways using a colicinogenic derivative of the leucine sensitive strain . It was found that leucine in a rather high concentration (2 mg/ml) prevented colicine production when given in the absence of phenylalanine, while phenylalanine at a very low dose (0.2 microgram/ml) could reverse this inhibition . The effect of leucine on colicine production, like lethality, operated only under certain conditions of culture dilution, but unlike lethality, was not very sensitive to the age of the culture . Tryptophane was found to resemble leucine in its effects on viability and on colicine production in liquid medium . Its effect was likewise reversed by a small amount of phenylalanine, and like leucine, tryptophane acted best only under very specific conditions of culture dilution.

Nucleic Acids Res, 1979 Mar, 6(3), 1041 - 8
2'-Deoxy-2'-fluorouridine-5'-triphosphates: a possible substrate for E . coli RNA polymerase; Pinto D et al.; dUflTP was tested as substrate in the E . coli RNA polymerase system using poly(dAT) as template . dUflTP could replace UTP when Mn++ was utilized as divalent cation instead of Mg++ . The level of transcription with the fluoro analog was then 55% of that with UTP.

Zh Mikrobiol Epidemiol Immunobiol, 1979 Mar, (3), 63 - 6
{Determination of the localization of the kcpA gene on the chromosome of E . coli O124 . I . Use of the type F' plasmids of varying length}; Lycheva TA et al.; The loss of virulence was observed in some of the transconjugates of E . coli O124 in the process of the transfer of the plasmids differing in length: F' 200 PS, F'x 573 and F'x 363, carrying the genes of the chromosome area lac--pur E . The genetic determinants contributing to the ability of E . coli O124 to produce keratoconjunctivitis seem to be localized near the lactose marker, and not near E as in Sh . flexneri . In E . coli O124 these genetic determinants are probably localized on both sides of the lactose operon.

Nucleic Acids Res, 1979 Mar, 6(3), 1189 - 201
Apparent allosterism by avian myeloblastosis virus reverse transcriptase and E . coli DNA polymerase I; Darling TL et al.; 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 polymerase reaction products are isolated chromatographically, then the polymerases obey classical Michaelis-Menten kinetics with respect to substrate and enzyme concentrations . These results suggest that the cooperative effects are an acid precipitation artifact . The results are also consistent with the enzyme operating by a distributive mechanism with the oligo(dT)12-18 primer.

Mol Cell Biochem, 1979 Feb 9, 23(3), 167 - 75
E . coli galactose-1-phosphate uridyl transferase: N-terminal and C-terminal sequences; Raychowdhury R et al.; A modified procedure for the purification of E . coli galactose-1-phosphate uridyl transferase (E.C . 2.7.6.12) was developed which reproducibly gives pure enzyme . The purified enzyme was shown to be a dimeric protein with a subunit molecular weight of 41,000 and its amino acid composition and content of free sulfhydryl groups were determined . The N-terminal and C-terminal amino acid sequences were found to be NH2-thr-gln-phe-asn-pro-val-asp and -ser(val leu)-ala-COOH respectively . This N-terminal sequence allowed the identification of the start of the transferase gene in the DNA sequence determined by GRINDLEY . Furthermore it appears to define a nine base intercistronic region between the epimerase and transferase genes.

Nature, 1979 Feb 8, 277(5696), 453 - 6
The E . coli gene encoding heat stable toxin is a bacterial transposon flanked by inverted repeats of IS1; So M et al.; Restriction endonuclease subclones of the Escherichia coli gene encoding the heat stable (ST) toxin exhibit a stem and loop structure similar to those seen in many procaryotic transposons . An EcoRI DNA fragment encoding tetracycline (Tc) resistance but no transposition functions was spliced into the ST gene in one of these subclones . By monitoring Tcr, we were able to show that the ST gene transposes . Restriction and DNA sequence data strongly suggest that the ST transposon, Tn 1681, is flanked by inverted repeats of IS1.

Biokhimiia, 1979 Feb, 44(2), 364 - 7
{Dependence of the rate of aspartate ammonia-lyase reaction catalyzed by free and immobilized cells of E . coli on temperature and preliminary thermal treatment}; Zueva NN et al.; The effects of temperature (45--55 degrees) and duration of thermal treatment on the L-aspartase activity of free and immobilized on polyacrylamide gel cells of E . coli, strain 85 were studied . It was found that preliminary thermal treatment of the cells at 50 degrees for 40--60 min is optimal for a high aspartase activity . Within the temperature interval of 20--55 degrees the temperature dependence of effective rate constants of L-aspartate synthesis obeys the Arrhenius equation, whereas the effective energy of activation is decreased from 12,6 to 3,6 kcal/mole, when the "activation" of the cells shows an increase.

Mol Gen Genet, 1979 Feb 1, 169(3), 337 - 43
Genetic organization of the E . coli chromosome around the structural gene for initiation factor IF3 (infC); Springer M et al.; A set of lambda transducing phages carrying varying lengths of the E . coli chromosome around the structural gene for initiation factor IF3 (infC) was derived from lambda p2 which is known to carry, besides infC, the structural genes for the alpha subunit of phenylalanyl-tRNA synthetase (pheS), the beta subunit of phenylalanyl-tRNA synthetase (pheT) and the structural gene for threonyl-tRNA synthetase (thrS) . The E . coli coding content of these derived phages was analysed by genetic complementation of a set of mutants and by SDS-polyacrylamide gel analysis of the proteins synthesized in UV irradiated cells infected with these phages . The segregation pattern of the different genes among these derived phages indicates that the order of the genes is pheT - pheS - "P12" - (infC, thrS) where infC is probably between "P12" and thrS . "P12" is the structural gene of a 12,000 molecular weight unidentified protein.

Mol Gen Genet, 1979 Feb 1, 169(3), 279 - 87
W-reactivation of phage lambda in recF, recL, uvrA, and uvrB mutants of E . coli K-12; Rothman RH et al.; W-reactivation is reduced by recF143 and recF144 mutations and is undetectable if a second mutation at either the uvrA or uvrB locus is combined with recF143 . The uvrA and uvrB mutations alone block W-reactivation partially . A recL152 mutation also partially blocks W-reactivation by itself . In combination with a uvrB5 mutation, recL125 blocks W-reactivation completely but in combination with recF143, significant residual W-reactivation ability remains . We suggest that the phenomenon of W-reactivation is the result of at least two modes or pathways . The observation that recF143 uvrB5 and recF143 uvrA6 strains permit normal levels of mutagenesis (Kato et al., 1977) but completely block all W-reactivation leads us to suggest further that the mechanism(s) of W-reactivation is at least partly different from that of UV mutagenesis.

Surgery, 1979 Feb, 85(2), 212 - 8
Amino acid metabolism in dogs with E . coli bacteremic shock; Woolf LI et al.; In 10 fasting dogs receiving 10(9) viable E . coli bacteria per kilogram intravenously, mean systolic blood pressure decreased from 120.6 +/- 15.1 to 82.2 +/- 12.8 mm Hg . The association of hypoglycemia and increased arterial alanine and glycine with elevated plasma glucagon implied impaired gluconeogenesis . A rapid elevation of blood urea concentration, indicating increased ureagenesis, a fall of blood glucose, and an increase of net urea synthesis relative to that of glucose suggested that an increased proportion of the carbon residues derived from glucogenic amino acids is catabolized via pathways other than gluconeogenesis . In the bacteremic dogs the absolute net release from the leg of valine, isoleucine, and leucine and their net release relative to the net rate of proteolysis were decreased, suggesting increased oxidation of these amino acids in skeletal muscle . An increased net release of alanine relative to the net rate of protein catabolism in muscle was in agreement with this contention.

Mol Gen Genet, 1979 Jan 16, 169(1), 35 - 40
In vitro replication of a DNA fragment containing the vicinity of the origin of E . coli DNA replication; Nusslein-Crystalla V et al.; The restriction nuclease cleavage pattern of E . coli DNA synthesized in vitro in the cellophane membrane system (Schaller et al., 1972) is similar to the one obtained after labelling E . coli in vivo . This is shown for exponentially growing cells and for cells synchronized by amino acid starvation followed by thymine starvation . In synchronized cells a piece of some 180 kilobase pairs is labelled containing oriC and neighbouring regions at 82 min on the genetic map of E . coli . A pulse label in vitro is incorporated into the same piece of DNA, but the center of this region, i.e . the EcoR1 fragment of 8.6 kbp length which contains the oriC region (Marsh and Worcel, 1977; v . Meyenburg et al., 1977; Yasuda and Hirota, 1977) is missing.

Mol Gen Genet, 1979 Jan 11, 168(3), 341 - 4
The isolation and genetic characteristics of lambda transducing phages of the uvrA+ and uvrC+ genes of E . coli K12; Auerbach J et al.; Lambda transducing phages carrying the excision repair genes uvrA+ and uvrC+ were selected from a pool of lambda phages carrying EcoR1 fragments of E . coli DNA . These phages and also lambdauvrB+ (obtained from Gottesman) were used to make lysogens of excision-defective strains carrying uvrA-, uvrB- or uvrC- . Lambda uvrA+ was found to transduce strains carrying uvrA- but not those carrying uvrB- or uvrC-, to normal ultraviolet resistance . Similarly, lambdauvrB+ and lambdauvrC+ were found to complement only the corresponding uvr- allele . The lambda transducing phages were co-transduced with gal+ by P1 phage into lysogenic gal- recipients, and presumably were integrated at the normal prophage site.

Mol Gen Genet, 1979 Jan 2, 167(3), 235 - 41
Close vicinity of IS1 integration sites in the leader sequence of the gal operon of E . coli; Kuhn S et al.; Four insertions of IS1 in the leader sequence of the gal operon of E . coli have been analysed . Two of them occur at the same position, but in opposite orientations . The other two are inserted one nucleotide to one side and four nucleotides to the other side, respectively . In each case, nine base pairs of the leader sequence of the gal operon are duplicated directly, and are found flanking the termini of IS1 at its junction with the gal operon . These repeated sequences differ from each other as expected from the different insertion sites.

Circ Shock, 1979, 6(3), 235 - 44
Failure of exogenous ATP and creatine phosphate to modify the course of E coli endotoxin shock in the cat; McCaig DJ et al.; Exogenous adenosine triphosphate (ATP) (in combination with MgCl2) and also creatine phosphate (CrP), have been administered intravenously to endotoxin-shocked cats . Untreated shocked cats exhibited systemic hypotension during the first hour and again from four hours . Cardiac output fell progressively, and markedly elevated arterial lactate levels were evident within one hour of endotoxin administration . Treatment with ATP (10 mg/kg every 30 minutes) during shock led to rapid hemodynamic deterioration in all cats; most of the cats were dead before completion of dosing (at three hours) . Long-lasting systemic hypotension and bradycardia were associated with this ATP administration and marked hypoglycemia developed in the survivors . Neither ATP (62 mg/kg) administered before endotoxin, nor CrP (500 mg/kg; administered either prior to endotoxin, or one hour afterwards) significantly modified the hemodynamic or metabolic changes associated with endotoxin shock in this species . Neither ATP nor CrP increased survival (assessed at five hours) . Other workers have demonstrated improved survival from shock with ATP treatment . There may be species differences in the responsiveness to exogenous ATP or, alternatively, a difference in the role of high-energy phosphates in different types of shock.

Adv Shock Res, 1979, 2, 233 - 44
Effects of methylprednisolone sodium succinate on clearance of live E coli from the peripheral blood of dogs; White GL et al.; Corticosteroids have been reported to potentiate infections, and yet recent clinical and experimental studies have documented their therapeutic effectiveness in both septic and endotoxin shock . This study was designed to determine if methylprednisolone sodium succinate (MP) affects the clearance of live E coli organisms from peripheral blood of dogs . The experimental group was pretreated with 30 mg/kg of MP, and controls received equal volumes of saline . Both control and MP-pretreated dogs significantly reduced the number of E coli in peripheral blood by almost two orders of magnitude; however, there was no significant difference in clearance of E coli organisms between the two groups . An initial leukopenia occurred in both groups after E coli injections; however, the subsequent development of leukocytosis in the MP group was significantly greater at +6 hours . Rectal temperatures were higher in the MP group from +1 through +4 hours than in the controls . Hyperglycemia developed initially in both groups, followed by a progressive hypoglycemia, with survivors returning to near normal blood glucose concentrations . Hemoconcentration occurred in both groups, with higher hematocrits being associated with mortality . Results support the view that methylprednisolone sodium succinate does not affect the clearance of live E coli organisms.

Antonie Van Leeuwenhoek, 1979, 45(1), 103 - 11
The effect of a plasmid on growth and survival of E . coli; Dale JW et al.; We studied the growth characteristics of a pair of Escherichia coli strains, isogenic apart from the possession of a nonconjugative plasmid . There was no difference between the two strains when they were grown separately . In mixed culture, a second slow phase of growth that normally occurred following the end of rapid exponential growth, was absent from the plasmid-carrying strain . This resulted in a considerable decrease in the proportion of the cells that carried the plasmid after overnight incubation . The effect of different conditions of growth is reported . The plasmid-carrying strain survived extended incubation (150 days at 37 degrees C) as well as did the plasmid free strain separately . In a mixture, the proportion of plasmid-carrying cells declined rapidly, and none was detected after 100 days.

Vet Med Nauki, 1979, 16(10), 74 - 80
{Hemagglutinating activity and morphology of antigen K 99 in enterotoxic strains of E . coli isolated from calves}; Petkov M et al.; The hemagglutination activity and morphology of antigen K 99 in enterotoxic E . coli strains isolated from calves was studied . It was proven that antigen K 99 is produced not at 18 degrees C, but at 37 degrees C . All K 99+ E . coli strains react with absorbed anti K 99 serum, showing various anti-agglutination titers . The hemagglutination activity of K 99+ E . coli strains is inhibited by absorbed K 99 antiserum . In immunodiffuse tests all K 99+ E . coli strains react by producing a single precipitation line . It is proven electronmicroscopically that on the surface of the bacterial cell of K 99+ E . coli strains is observed a filamentous structure, consisting of numerous fine fibers which give it a fibriform outlook . No such morphological structures are observed in K 99- E . coli strains.

Nucleic Acids Symp Ser, 1979, (6), s195 - 8
Synthesis of the nascent strand of tRNAfMet from E coli; Ohtsuka E et al.; Oligonucleotides corresponding to the total tRNAfMET FROM E . coli have been synthesized . These fragments were joined by using RNA ligase to yield quarter molecules . The 5'-quarter molecule showed 84% amino acid acceptor activity when it was combined with the natural three quarter molecule.

Vet Med Nauki, 1979, 16(9), 24 - 8
{Hemagglutinating activity of enterotoxic strains of E . coli isolated from calves}; Petkov M et al.; The manose-resistant hemagglutination activity of 272 E . coli strains isolated from calves sick or dead of colibacteriosis, 43 of which were enteropathogenic, was assessed . Strain enteropathogeneity was determined after the method of Smith and Halls (1967) . It was established that 38 (88.3%) of the 43 enteropathogenic strains cause full or partial hemagglutination of horse or pig erythrocytes . Manose-resistant hemagglutination was not observed in the non-enteropathogenic E . coli strains . Manose-resistant hemagglutination of enterotoxic E . coli strains is in relation with their enteropathogeneity.

Mol Gen Genet, 1979, 177(1), 129 - 37
Indirect and intragenic suppression of the lexA102 mutation in E . coli B/r; Volkert MR et al.; In Escherichia coli B/r the expression of UV inducible (SOS) functions is under the control of the recA and lexA genes . In this study we have characterized mutants which are altered in their ability to express SOS functions . These mutants were isolated as UV resistant UV nonmutable (Rnm) derivatives of the lexA102 uvrA155 mutant strain WP51 . The UV resistance of these Rnm strains is a result of the suppression of lexA102 mediated UV sensitivity . Genetic mapping of rnm mutations shows that the two predominant classes, rnmA and rnmB, map in or very near the lexA and recA genes respectively . rnmA mutations differ from rnmB with regard to recA protein synthesis, rnmA mutations do not restore the ability to express high levels of recA protein after UV treatment whereas rnmB mutations result in constitutive expression of high levels of recA protein . However, both rnmA and rnmB mutant strains inhibit postirradiation DNA degradation . This shows that in rnmA strains, high levels of recA protein are not needed to inhibit postirradiation DNA degradation . The genetic map location and constitutive expression of recA protein synthesis resulting from rnmB mutations suggests that they are operator constitutive mutations of the recA gene . The result that the lexA+ gene is required for the expression of UV mutagenesis in rnmB mutants shows that high levels of recA protein do not circumvent the need for the lexA+ gene product in this process . Thus, while the lexA gene product is required for the induction of recA protein synthesis, lexA must have an additional role in UV induced mutagenesis.

Contrib Microbiol Immunol, 1979, 6, 78 - 88
Recombination between the plasmid prophages P1 and P7 and the E . coli chromosome; Chesney RH et al.; The prophages of the related temperate phages P1 and P7, which normally exist as plasmid DNA, suppress E . coli dnaA(Ts) by integrating into the host chromosome . Integratively suppressed strains may either be capable of producing phage or may have prophage deletions . In strains containing non-defective prophages, the location of the site on the prophage used for integrative recombination was identified by use of restriction analysis and DNA-DNA hybridization techniques . At least seven different integration sites were found on the prophage; the site used most often may be at the 'end' of the genetic map generated by vegetative phage crosses . For suppression of P1 and P7, the sites on the host chromosome utilized for prophage integration are not distributed randomly.

Vet Med Nauki, 1979, 16(1), 72 - 6
{Transmissible drug resistance in strains of E . coli isolated from birds}; Kandov P; A total of 97 strains of Escherichia coli, resistant either to one or to several theraupeutic agents and isolated from young and adult birds, were studied for the presence of transmissible R plasmids . Transmissible drug resistance was demonstrated with 37 per cent of the strains . The transmission of such resistance was manifested in highest percent in the case of ampicillin and chloramphenicol, followed by sulphathiazole and tetracycline . The R plasmids established in multi-drug resistant strains with three markers and more, were found to bear high percent determinants of resistance to chloramphenicol and in lower percent such to sulphathiazole and tetracycline . The same strains presented R plasmids that bore determinants of resistance to five therapeutic agents (Tc, Su, Cm, Mm, Nm) and to three therapeutic agents (Cm, Ap, Tc) and (Cm, Su, Km).

Chem Biol Interact, 1979, 28(1), 61 - 70
Biological activity of metal complexes . I . Interaction of pt(II), pd(II) and rh(I) complexes with E . coli strains and with mice LS fibroblasts in vitro; Aresta M et al.; The effects of a number of Pt(II, Pd(II) and Rh(I) complexes against cultures of Escherichia coli (strains B, H10178, uvra-, recA-) and cultures of mice LS Fibroblasts were tested . Most of the compounds showed higher cytotoxic activity than the cis-Pt(NH3)2Cl2, the compound at present on clinical trial as antittumour drug . A new model of active compound is proposed.

Ann Sclavo, 1979 Jan-Feb, 21(1), 53 - 7
{R factors influence on motility of "E . coli" and "S . typhimurium" (author's transl)}; Perduca M et al.; Influence on the motility of E . coli and S . typhimurium strains by several R factors has been studied; both classes of inhibiting and stimulating R factors have been detected; the plasmidic effect on the motility can be inverted by transfer to another carrier strain.

J Perinat Med, 1979, 7(1), 23 - 6
Neonatal E . coli pericarditis; Wynn RJ; A review of the literature reveals only one case of neonatal Escherichia coli pericarditis . This is a case report of Escherichia coli pericarditis occurring in a two day old infant . The infant initially presented with lethargy and jaundice but this rapidly progressed into shock . Despite vigorous resuscitative efforts, the infant succumbed and at autopsy 30 cc of purulent fluid were obtained . Cultures of the admission blood and post-mortem pericardial effusion grew Escherichia coli . The clinical diagnosis of pericarditis is often difficult because of vague, nonspecific symptoms and signs . The symptoms are usually those of sepsis plus those of impaired circulation due to mechanical embarrassment by accumulating pericardial effusion . It is difficult to differentiate pericarditis with effusion from myocarditis and pericardial effusion secondary to congestive heart failure . The use of pericardiocentesis as a diagnostic tool and echocardiography are the most helpful techniques presently available for diagnosis . Management consists of vigorous supportive efforts, antibiotics, and drainage of the pericardial effusion . Because of the very high mortality associated with this disorder, a high index of suspicion with a vigorous diagnostic and therapeutic approach to the patient is indicated.

Circ Shock, 1979, 6(4), 343 - 55
Prolonged shock in the monkey following live E coli organism infusion; Coalson JJ et al.; Responses of the rhesus monkey to the administration of live Escherichia coli organisms during an observation of 0--27 hours were studied . Nine monkeys were infused for 30 minutes with live E coli organisms, the dose ranging between 7.6 X 10(9) and 3.0 X 10(11) organisms/kg . Three of nine animals survived for 24 hours or longer . Nonsurvivors demonstrated significant hypotension, hypoglycemia, and hypoinsulinemia, while survivors showed lesser degrees of physiologic derangement . Findings were hepatic sinusoidal fibrin thrombi and hepatocellular damage accompanied by elevated serum enzymes . The kidney did not show glomerular fibrin thrombi; however, tubular lesions were clearly evident and increases in blood urea nitrogen levels and endogenous creatinine were documented . Lungs of animals surviving longer contained fewer polymorphonuclear leukocytes and platelets than were seen in acute shock studies . This study emphasizes the importance of monitoring the nonhuman primate during an extended time period, since many significant pathophysiologic responses occur after eight hours of observation.

Biochimie, 1979, 61(8), 881 - 9
Function of individual E . coli 30 S ribosomal proteins as determined by in situ immunospecific neutralization: a tentative classification; Lelong JC et al.; The accessibility of each 30S subunit protein to their cognate antibodies (IgG or Fabs) having been previously well established, the effect of their in situ specific neutralization by monovalent IgG fragments (FabI) are reported for five reactions: 1) T4 and R17 RNA directed protein synthesis: 2) polyphenylalanine synthesis: 3) enzymatic Phe-tRNA binding in the presence of 30S + 50W subunits: 4) fMet-tRNAf binding to the 30S subunit in the presence of initiation factors IF1, IF2, IF3; 5) coupling with lambda plac DNA transcription of the initial translation step (i.e., interaction of IF3 activated 30S subunits with nascent mRNA, in the absence of tRNA) . According to evident similarities in their inhibition pattern concerning the five reactions tested, 30S subunit proteins can be classified in five categories which are discussed in terms of functional topography.

Quad Sclavo Diagn, 1978 Dec, 14(4), 536 - 50
{Pathogenicity of E . coli: biological aspects and problems related to laboratory diagnosis (author's transl)}; Patriarca P et al.; The biological properties which may contribute to the pathogenicity of E . coli are reviewed in this article . Specifically the following topics are discussed in detail: 1) adhesion to the intestinal epithelial cells, 2) production of enterotoxins, 3) invasiveness of and ability to multiply within the epithelial cells, 4) insensitivity to complement lysis or inability to activate the alternative pathway of complement, 5) resistance to phagocytic killing . The various techniques which might be of potential usefulness in the clinical laboratory to test the parameters of the pathogenicity of E . coli are briefly outlined . The dissociation between the definition of pathogenicity, as established on the basis of the results of E . coli serotyping, and the criteria of pathogenicity listed above is brought to the attention of the reader . As specificity regards the toxinogenicity, what emerged from a survey of the literature, was that only one of the so called "enteropathogenic" strains of E . coli, according to the serotype classification, was found to produce an enterotoxin.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Dec, 34(6), 537 - 45
The response of E . coli Bs-1 to tritium-beta particles under aerated and anoxic conditions; Lunec J et al.; E . coli Bs-1 cells were exposed to acute doses of tritium-beta particles by suspension in tritiated water for known lengths of time . The resulting survival rate was compared with that obtained for external irradiation with 7 MeV electrons . The o.e.r . measured for tritium-beta s was not significantly different from the value of 2.15 measured for 7 MeV electrons . The r.b.e . of the tritium beta s relative to 7 MeV electrons was 1.21 in both air and nitrogen . These results were compared with existing data for low voltage electron irradiations and with track segment studies of the effect of varying LET on the radiosensitivity of E . coli Bs-1.

Can J Microbiol, 1978 Dec, 24(12), 1607 - 13
Factors influencing the in vivo stability of L-serine deaminase activity in E . coli K12; Beeraj RD et al.; L-Serine deaminase (L-SD) is unstable in intact cells of Escherichia coli K12 . The extent of this instability is dependent on the nitrogen content of the medium in which the enzyme is synthesized, and on that in which it is tested . Enzyme activity in cells grown with an inorganic nitrogen source is unstable in the presence of inorganic nitrogen; enzyme activity in cells grown with an organic nitrogen source is unstable in the presence of the amino acids glycine and leucine.

Nucleic Acids Res, 1978 Dec, 5(12), 4933 - 47
RNA-RNA interactions in the binding site of protein L24 on 23S ribosomal RNA of E . coli . II . Sequence analysis of the interacting fragments; Krol A et al.; A ribonucleoprotein complex containing several RNA subfragments from the 5' part of 23S RNA was recovered after digestion of the reconstituted complex between 23S RNA and protein L24 . It was suggested in the preceding paper that the RNA subfragments 4B, 10A and 9, which are widely separated in the sequence, strongly interact . These subfragments were previously partially sequenced by the classical fingerprinting methods . Their sequences have now been completed with rapid new RNA sequencing methods . We propose here a base-pairing model showing how these subfragments may interact with one another.

Nucleic Acids Res, 1978 Dec, 5(12), 4837 - 53
Participation of X47-fluorescamine modified E . coli tRNAs in in vitro protein biosynthesis; Sprinzl M et al.; The reaction of fluorescamine with primary amino groups of tRNAs was investigated . The reagent was attached under mild conditions to the 3'-end of tRNAPhe-C-C-A(3'NH) from yeast and to the minor nucleoside x in E . coli tRNAArg, tRNALys, tRNAMet, tRNAIle and tRNAPhe . The primary aliphatic amino groups of these tRNAs react specifically so that the fluorescamine dye is not attached to the amino groups of the nucleobases . E . coli tRNA species modified on the minor nucleoside X47 can all be aminoacylated . An involvement of the minor modified nucleoside X47 in the tRNA: synthetase interaction is detected . Native tRNALys-C-C-A from E . coli can be phenylalanylated by phenylalanyl-tRNA synthetase from yeast, whereas this is not the case for fluorescamine treated tRNALys-C-C-A(XF47) . Pre-tRNAPhe-C-C-A(XF47) forms a ternary complex with the elongation factor Tu:GTP from E . coli, binds enzymatically to the ribosomal A-site and is active in poly U dependent poly Phe synthesis . Fluorescamine-labelled E . coli tRNAs provide new substrates for the study of protein biosynthesis by spectroscopic methods.

Nucleic Acids Res, 1978 Dec, 5(12), 4613 - 23
The attenuator of the tryptophan operon in E.coli: rho-mediated release of RNA polymerase from a transcription termination complex in vitro; Fuller RS et al.; In vivo, termination of transcription at the attenuator site of the tryptophan (trp) operon of E . coli is influenced by the protein termination factor rho . In vitro, termination does not depend on rho factor, and is very efficient in a purified system consisting only of RNA polymerase, the DNA template, nucleoside triphosphates, and buffer . The extent of termination in this system is unaffected over a wide range of salt and nucleoside triphosphate concentration . However, there is a 10-fold stimulation of trp leader mRNA synthesis if rho factor is present during the transcription reaction . This stimulation occurs only at low molar ratios of polymerase to template, and can be blocked by rifampicin . It is thus most likely due to the recycling of RNA polymerase molecules that have been released from the attenuator site by rho factor . In fact, transcription of the trp leader region in vitro results in the fomration of a stable termination complex which can be observed on sucrose gradients or by binding to nitrocellulose filters . These data indicate that a major function of rho at the trp attenuator is to release completed transcripts from a pre-formed termination complex, rather than to cause the cessation of elongation.

Biokhimiia, 1978 Dec, 43(12), 2183 - 8
{The effect of guanosinetetraphosphate on rRNA synthesis in E . coli extracts}; Perel'man BV et al.; The synthesis of rRNA in the ribosome-free extracts S100 of E . coli cells was about 30 and 60% of total transcript when E . coli DNA and DNA of lambda rifd 18 phage were used respectively . The synthesis of rRNA with both types of DNA was inhibited in 5--6 times by 0.8 mM ppGpp, while the synthesis of total RNA decreased only two-fold . Selective action of ppGpp on rRNA synthesis is due to the intensive inhibition of the initiation of transcription of the appropriate genes . The rRNA synthesis and the inhibitory capacity of ppGpp was shown to dependend on the KCl concentration in S 100 extracts . These results indicate that ppGpp is the main factor controlling rRNA synthesis both in isolated RNA polymerase system and in cell-free extracts.

Cell, 1978 Dec, 15(4), 1221 - 30
Sensory adaptation mutants of E . coli; Parkinson JS et al.; The ability of E . coli to adapt to constant levels of attractant and repellent chemicals was studied by examining the patterns of flagellar movement in cells subjected to abrupt concentration changes . Wild-type bacteria exhibited transient responses to such stimuli, in support of previous findings . Nonchemotactic mutants of the cheX class responded to both attractants and repellents, but were unable to terminate these behavioral changes as long as the stimulating chemical was present . The sensory adaptation defect of cheX strains may be due to an inability to methylate several cytoplasmic membrane proteins that initiate changes in flagellar movement in response to chemoreceptor signals . Based on these results, possible mechanisms of stimulus transduction and sensory adaptation during chemotaxis are discussed.

Biokhimiia, 1978 Dec, 43(12), 2154 - 62
{Aminoglycoside-3'-phosphotransferase I from aminoglycoside-polyresistant strain E . coli 182}; Ganelin VL et al.; An aminoglycoside-3'-phosphotransferase I catalyzing phosphorylation of some aminoglycoside antibiotics with the 3'-hydroxyl group has been purified from the cells of aminoglycoside resistant strain E . coli 182 by competitive affinity chromatography on neomycin-Sepharose and gel-filtration on Sephadex G-100 . The product of enzymatic phosphorylation of kanamycin A was isolated and identified as kanamycin-3'-phosphate by NMR, thin-layer chromatography and chemical characterization . The kinetic properties of the enzyme were studied . The pH-optimum was between 7,8--8,0; the {S}0.5 values for kanamycin, neomycin and paromomycin were 2.10(-5) M, the energy of activation was 15,9 kcal/mol . The bivalent cations were required for activity of the enzyme, Mg2+ was the most effecient . The relative aminoglycoside antibiotics containing no 3'-hydroxyl group were competitive inhibitors of the enzyme activity with Ki values close to {S}0.5.

Biokhimiia, 1978 Dec, 43(12), 2261 - 4
{Affinity alkylation of E . coli RNA-dependent DNA polymerase with TTP gamma-amidate derivatives}; Buneva VN et al.; 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.

Mol Gen Genet, 1978 Nov 9, 166(3), 329 - 36
Functional mRNA half lives in E . coli; Pedersen S et al.; Analysis of the synthetic rate of individual protein species at various times after complete inhibition of transcription with either streptolygidin or rifampicin was carried out by two-dimensional polyacrylamide electrophoresis of total Escherichia coli cell extracts . The decay rate of the potential to synthesize different proteins was assumed to be equal to the functional decay rate of the corresponding mRNA . We conclude the following: (a) The tufA and tufB messengers have different half lives (3.0 and 2.4 min, respectively) . (b) Different genes within the same transcriptional unit can have different half lies (S7, EGF and EFTuA--2.5, 3.8 and 3.0 min, respectively) . (c) There is at least a twenty-fold variation in individual mRNA half lives in E . coli; ribosomal protein S1 mRNA was observed to have the shortest half life in the cell (40 sec), while the longest observed half life was approximately 20 min (all values at 30 degrees C) . (d) Addition of rifampicin increases the absolute rate of RNA polymerase subunit alpha and beta synthesis two-fold . (e) The induction of the synthesis of alpha subunit of RNA polymerase takes place without a concomitant induction of ribosomal protein S4 and L17, which are reported to be on either side of alpha in the same transcriptional unit.

Nature, 1978 Nov 2, 276(5683), 33 - 7
Identification of a single promoter in E . coli for rplJ, rplL and rpoBC; Linn T et al.; A set of restriction fragments cloned into phage lambda vectors has allowed us to locate a site necessary for full rpoBC expression . We find that these genes for the two large subunits of RNA polymerase and the genes, rplL and rplJ, for two ribosomal proteins, form a single operon.

Cell, 1978 Nov, 15(3), 1055 - 66
Structural analysis and in vitro processing to p5 rRNA of a 9S RNA molecule isolated from an rne mutant of E . coli; Ghora BK et al.; A temperature-sensitive mutant of E . coli, rne (RNAase E-), accumulates a number of relatively small RNA molecules at the nonpermissive temperature . One of these molecules, 9S, contains 5S rRNA sequences . The 9S RNA can be processed in vitro to 5S (p5) and a 4S-sized molecule . The 9S and the p5 and 4S RNAs processed from it were all characterized by RNAase T1 fingerprinting and pancreatic RNAase redigestion analysis . Unique oligonucleotides found in the p5 and the 4S RNA are present as unique oligonucleotides in the 9S RNA, suggesting that each 9S molecule contains one 5S and one 4S RNA moiety . Since the 9S RNA contains about 420 nucleotides, and intervening sequences are not known to exist in E . coli, the 5S an 4S RNAs cannot be more than 200 nucleotides apart in the genome . E . coli contains at least three different sequence variants of 5S rRNA, all of which can be identified in the 9S transcript, indicating that 9S RNA is transcribed from most, if not all, of the active rRNA genes, and that RNAase E processes transcripts derived from all these rRNA genes . No modified bases were found in the 4S RNA, nor was its sequence compatible with the known sequences of tRNAs found near the 5S rRNA . We therefore conclude that the 9S RNA doses not contain tRNA, and that the tRNA molecules located near the 5S rRNA are distal to it.

Nucleic Acids Res, 1978 Nov, 5(11), 4215 - 23
Isolation of Q nucleoside precursor present in tRNA of an E . coli mutant and its characterization as 7-(cyano)-7-deazaguanosine; Noguchi S et al.; One of the E . coli mutants selected for deficiency of modified nucleoside Q was found to contain an analogue of Q and normal guanosine in place of Q . The analogue of Q, designated as preQo, was isolated on a large scale from purified tRNATyr containing preQo . The structure of preQo was determined to be 7-(cyano)-7-deazaguanosine by comparison of its ultraviolet absorption spectra, thin-layer chromatographic mobility and mass spectrum with those of synthetic material.

Gene, 1978 Nov, 4(3), 241 - 59
Transcription and translation in E . coli of hybrid plasmids containing the catabolic dehydroquinase gene from Neurospora crassa; Alton NK et al.; Two hybrid plasmids which carry the gene for Neurospora crassa catabolic dehydroquinase (C-DHQase) and complement an aroD6 (dehydroquinase-deficient) auxotroph of Escherichia coli have been analyzed . One of these contains a 2.9 kilobase (kb) fragment cloned in the HindIII site of plasmid pBR322 (pVK57) and the other contains a 6.8 kb fragment cloned in the PstI site (pVK88) . Restriction enzyme mapping of these plasmids has demonstrated that the 2.9 kb fragment is totally contained within the 6.8 kb fragment . When the polarity of either the HindIII fragment or PstI fragment was reversed with respect to pBR322 no effect was observed on either the ability of the hybrid to complement an aroD- auxotroph or on the level of C-DHQase activity . In vivo transcription of plasmid pVK88 in both orientations was analyzed by RNA-DNA hybridization and by the techniques developed by Southern (1975) . Approx . 40% of the plasmid-directed transcription occurred from the cloned PstI fragment and 60--70% of these N . crassa transcripts were encoded by the 2.9 kb HindIII fragment . The Southern technique allowed a further localization of the region of most extensive transcription to a 1.8 kb HindIII-EcoRI fragment . Biochemical analysis revealed that the C-DHQase protein produced by strains harboring pVK57 and pVK88 in either orientation was identical to the N . crassa enzyme . Furthermore, when these plasmids were segregated into minicells and labeled with 14C amino acids, the C-DHQase protein was synthesized at a level comparable to other plasmid-encoded proteins . Taken together, these experiments demonstrate that transcription is efficiently initiated in E . coli from a site on the cloned N . crassa DNA and that the resulting C-DHQase mRNA is efficiently and accurately translated.

Antibiotiki, 1978 Nov, 23(11), 989 - 93
{Makeup and properties of E . coli cells with a varying level of resistance to tetracycline}; Kuzina ZA et al.; Lipopolysaccharide composition of tetracycline sensitive and resistant strains of E . coli was studied comparatively . It was shown that that resistance of E . coli to tetracycline was probably due to the differences in the lipopolysaccharide component composition of the outer membrane . On the basis of the activity comparison of the Mg2+- and Ca2+-activated ATP-ase of the membrane fraction of the tetracycline sensitive and resistance strains of E . coli it was concluded that the resistance development in the strains tested to tetracycline was not associated with the changes in the ATP-ase activity.

Acta Paediatr Scand, 1978 Nov, 67(6), 705 - 8
Immunodeficiency in Down's syndrome . Titres of "natural" antibodies to E . coli and rabbit erythrocytes at different ages; Ugazio AG et al.; "Natural" antibody titres to E . coli O antigens of different serotypes and to rabbit red blood cells were determined in 86 subjects with Down's syndrome and 79 mentally retarded but chromosomally normal controls ranging in age from 10 months to 52 years . Subjects in the two groups were matched for sex, age and socio-environmental conditions . Titres of both antibodies, assessed by haemagglutination, were significantly lower in subjects with DS in the 1 to 5 year old group . E . coli antibodies transiently increased to normal values in subjects with DS during the second 5 years of life, thereafter rapidly declining to levels significantly lower than those observed in controls . The titres of antibodies to rabbit erythrocytes in subjects with Down's syndrome showed a more variable course transiently approaching normal values in the 7-10 year group and after 20 years of age . These data are interpreted as further evidence for the existence of a congenital immunodeficiency in Down's syndrome.

Wien Klin Wochenschr, 1978 Oct 27, 90(20), 717 - 21
{Inhibition of opsonization of E . coli by enzyme-treated gammaglobulin (author's transl)}; Eibl M et al.; 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 competitively inhibited opsonization, whilst plasmin-treated gammaglobulin potentiated at the low and competitively inhibited at higher dilutions . In serum from patients with antibody-deficiency syndromes, potentiation of opsonization by Cohn fraction II and competitive inhibition by pepsin- and plasmin-treated gammaglobulins was already seen at low serum dilutions.

Nature, 1978 Oct 19, 275(5681), 617 - 24
Phenotypic expression in E . coli of a DNA sequence coding for mouse dihydrofolate reductase; Chang AC et al.; The construction and analysis of bacterial plasmids that contain and phenotypically express a mammalian genetic sequence are described . Such plasmids specify a protein that has enzymatic properties, immunological reactivity and molecular size characteristic of the mouse dihydrofolate reductase, and render host cells resistant to the antimetabolic drug trimethoprim.

Nucleic Acids Res, 1978 Oct, 5(10), 3759 - 73
A computer aided oligonucleotide analysis provides a model sequence for RNA polymerase-promoter recognition in E.coli; Scherer GE et al.; A novel computer procedure has been used to search for homology among 17 known procaryotic promoter sequences . A model sequence, :formula: (see text), is compatible with the properties of all known promoter and operator mutations, predicts base positions for the initiation of RNA synthesis coinciding with those determined experimentally, is compatible with current models for the regulation of transcription, suggests that RNA polymerase could recognize the DNA double helix firstly in the B conformation then in the A.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Oct, 34(4), 317 - 27
Extensive and equivalent repair in both radiation-resistant and radiation-sensitive E . coli determined by a DNA-unwinding technique; Ahnstrom G et al.; The extent of strand breakage and repair in irradiated E . coli B/r and Bs-1 was studied using a DNA-unwinding technique in denaturing conditions of weak alkali . Although these two strains show widely different responses to the lethal effects of ionizing radiation, they both have an equal capacity to repair radiation-induced breaks in DNA . Oxygen enhancement ratios for the killing of B/r and Bs-1 were respectively 4 and 2; but after repair in non-nutrient or nutrient post-irradiation conditions, the oxygen enhancement values for the residual strand breaks were always the same for the two strains . The equal abilities of E . coli B/r and E . coli Bs-1 to remove the strand breaks measured by this weak-alkali technique leads us to suggest that some other type of damage to either DNA or another macromolecule may play a major role in determining whether or not the cells survive to proliferate.

Gene, 1978 Oct, 4(2), 137 - 52
Cloning of an E . coli ribosomal RNA gene and its promoter region from lambdarifd18; Kiss A et al.; The DNA of the specialized transducing phage lambdarifd18, which carries a bacterial rRNA transcription unit, was digested with restriction enzymes EcoRI and/or BamHI . Attempts were made to clone fragments containing the presumed rRNA promoter region or the entire rRNA gene in RSF2124 or pBR313 plasmid vectors with the following results: (1) We failed to clone an EcoRI fragment with the rRNA promoter region in plasmid RSF2124 . (2) A smaller EcoRI-BamHI fragment with the rRNA promoter was also unclonable by itself, but one recombinant was found containing this fragment together with another large (7 Mdaltons) fragment, derived from phage lambda . The presence of this large fragment proved to be essential . The identity of these DNA fragments in the recombinant clone was confirmed by redigestion with several restriction enzymes, hybridization with rRNA, and in vitro transcription experiments, which showed preferential rRNA transcription . (3) A BamHI fragment encompassing the entire rRNA gene was easily cloned . Such stable clones carried a doubled number of rRNA genes . In vitro transcription using the recombinant plasmid resulted in 70% rRNA transcription . These recombinant clones allow the easy purification of the relevant DNA fragments for further investigation including sequencing.

Cell, 1978 Oct, 15(2), 527 - 39
Processing of rRNA by RNAase P: spacer tRNAs are linked to 16S rRNA in an RNAase P RNAase III mutant strain of E . coli; Gegenheimer P et al.; To determine which enzymes are responsible for the processing cleavages of ribosomal RNA transcripts in Escherichia coli, we constructed a mutant strain lacking RNAase III and containing a thermolabile RNAase P . At the nonpermissive temperature, this strain accumulates a novel "19S" RNA species which contains 17S precursor rRNA sequences covalently linked to tRNA sequences transcribed from the ribosomal RNA spacer region between the 16S and the 23S rRNA cistrons . In vitro treatment of 19S RNA with cell extracts releases tRNA2Glu and other tRNA species . These "spacer" tRNA sequences are apparently not contained with the 18S RNA species found in an RNAase III- RNAase P+ cell . RNAase P-deficient extracts are incapable of cleaving space tRNA from 19S RNA, indicating that RNAase P is required for the release of spacer tRNAs from rRNA transcripts of E . coli cells.

Biokhimiia, 1978 Oct, 43(10), 1783 - 9
{Interrelationship between metabolic and genetic regulation of alkaline and acid phosphatases in E . coli cells}; Nesmeianova MA et al.; The effect of exogenous orthophosphate and mutations in regulatory genes of alkaline phosphatase on the level of nonspecific acid phosphatase was studied . The level of this enzyme as well as the level of alkaline phosphatase were shown to be regulated by exogenous orthophosphate being derepressed under phosphate starvation . The derepression of acid phosphatase is accompanied by more rapid secretion of enzyme from membranes to soluble fraction . Mutations in all the four regulatory genes decrease the level of enzyme in cells . Genes phoR and phoS, participating in regulation of alkaline phosphatase, are required for the derepression of acid phosphatase under the conditions of phosphate starvation.

Br J Pharmacol, 1978 Oct, 64(2), 185 - 91
E . coli endotoxin shock in the dog; treatment with lidocaine or indomethacin; Fletcher JR et al.; 1 Dogs treated with lidocaine (1 mg kg-1 h-1) or indomethacin (1.5 mg/kg) before and after an LD60 dose (1 mg/kg) of E . coli endotoxin survived for at least 72 h . 2 Although all dogs in both treated groups survived, only those treated with indomethacin were significantly protected against the fall in the arterial blood pressure 1 to 2 min following endotoxin administration . 3 Endotoxin increased the plasma prostaglandin F2alpha (PGF2alpha) concentration in the control and lidocaine-treated groups, however, no increase was observed with indomethacin treatment . 4 Neither lidocaine nor indomethacin alone had any significant effect on the parameters measured in this model . 5 Following the administration of endotoxin, lidocaine-treated animals had significantly decreased plasma fibrinogen concentrations when compared to the other groups . 6 This study suggests that lidocaine, a local anaesthetic and a drug widely used for cardiac arrhythmias, might offer protection in endotoxin shock.

Eur J Immunol, 1978 Oct, 8(10), 688 - 92
Immune response against the beta-galactosidase enzyme of E . coli at precursor cell level . I . Analysis of the secondary repertoire in BALB/c mice; Accolla RS et al.; 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 out of 90 000 and appears to be fairly constant among different individual mice . Further, the degree of heterogeneity of protecting antibodies analyzed in one individual is very high (250-fold difference in affinity) but comparable to other secondary repertoires . Specific frequencies are compared with previous findings relative to secondary responses against artificial haptens . It is suggested that a different type of recognition exists between protein determinants and artificial haptens . In addition, the relatively high proportion of clones making antibodies of the protecting type suggests that only a small proportion of antigenic sites on the beta-gal is actually able to stimulate an immune response.

Nucleic Acids Res, 1978 Oct, 5(10), 3855 - 69
Phosphorus-31 NMR studies of E . coli ribosomes; Tritton TR et al.; Phosphorus-31 nuclear magnetic resonance spectra, relaxation times and nuclear Overhauser (NOE) enhancement have been measured for E . coli ribosomes, subunits and rRNA . NOE and T1 experiments reveal that the phosphorus relaxation in this organelle is largely dipolar in origin . Moreover these results imply the presence of internal motion within the RNA chain with a correlation time of about 3-5 x 10(-9) sec . In all cases the predominant resonance is centered at about -1.5 ppm (relative to 85% H3PO4) as expected for a phosphodiester linkage where there is a large degree of double helix . The linewidth narrows by about a factor of four when the ribosomal proteins are removed indicating a substantial immobilization of the RNA when it is assembled into the ribosome . In addition to the phosphodiester resonance, ribosomes also reveal one or two narrower resonances shifted to low field by 1-4 ppm . Based on the observation that these resonances show a pH dependent chemical shift, we assign them to phosphate monoesters i.e . terminal 3' or 5' phosphate groups . These terminal phosphates are due to short oligomers of RNA derived from the terminus of the chain.

Mol Biol (Mosk), 1978 Sep-Oct, 12(5), 1085 - 95
{Modification of one tRNA recognition site of phenylalanyl-tRNA synthetase from E . coli MRE-600 with N-chlorambucilyl-phenylalanyl-tRNA}; Ankilova VN et al.; Affinity labelling of phenylalanyl-tRNA synthetase from E . coli MRE-600 with N-chlorambucilyl-phenylalanyl-tRNA results in a binding of 1 mole of the reagent per 1 mole of the enzyme . Exhaustive alkylation of phenylalanyl-tRNA synthetase completely blocks the aminoacylation and partially inhibits the reaction of ATP--{32P}pyrophosphate exchange . Removal of the tRNA moiety of the reagent by hydrolysis of the ester bond N-chlorambucilyl-phenylalanine and terminal adenosine does not result in a restoration of ATP--{32P}pyrophosphate exchange and aminoacylation activity . The latter result may testify a chemical modification of amino acid residues essential for enzymatic activity . Possibility of blocking one of the two tRNA binding sites is discussed.

Biokhimiia, 1978 Sep, 43(9), 1718 - 20
{Sensitivity of chromosomal and plasmid E . coli DNA to restriction endonuclease Eco RII}; Guseinov OA et al.; It was shown that E . coli C, E . coli MRE 600 DNA, and also plasmid DNA of Col E1, RSF 2124 from E . coli K-12, and plasmid DNA from E . coli MRE 600 were completely resistant against restriction endonuclease R . Eco RII . Plasmid DNAs of Col E1, RSF 2124 amplificated for 4 hours in the presence of chloramphenicol are sensitive to R . Eco RII but after 16-hour amplification in the presence of chloramphenicol these DNAs acquire complete resistance against R . Eco RII . These data point to the slower rate of modification of DNA in vivo by DC-methylases of Eco RII type in comparison with DNA methylase Eco RII.

Biokhimiia, 1978 Sep, 43(9), 1680 - 7
{Induction of E . coli alkaline phosphatase synthesis in cells preincubated at low temperatures}; Evdokimova OA et al.; Cell preincubation at lowered t degrees was found to result in increased alcaline phosphatase synthesis . The ability of cells for increased alcaline phosphatase synthesis correlates with increased content of cis-vaccinic acid and higher liquidity of lipids . It has been ascertained that modifications caused by cell preincubation at lowered t degrees favour the greater stability of mRNA coding the alcaline phosphatase.

Cell, 1978 Sep, 15(1), 231 - 6
Isolation and characterization of a promoter mutant in the str ribosomal protein operon in E . coli; Post LE et al.; The lambda fus3 transducing phage carries several operons for ribosomal proteins of E . coli, including the str operon . A mutant transducing phage with a promoter mutation in this operon has been isolated . This mutant shows reduced stimulation of synthesis of proteins encoded by the operon, S12, S7, and elongation factors G and Tu, in ultraviolet-irradiated cells . This mutation also abolishes in vitro transcription from the str promoter . The DNA sequence of the mutant promoter shows that it is a point mutation 6 bases upstream from the in vitro transcription start site, changing the "Pribnow box" sequence from TAAAATT to TAAAACT . These results indicate that the site altered by the mutation, which is in the region just preceding the transcription start site, is important for the expression of the str operon.

Antibiotiki, 1978 Sep, 23(9), 779 - 85
{2 types of auxotrophic mutants occurring by insertion of the ampicillin transposon into the chromosome of E . coli K-12}; Gordienko IV et al.; Insertion of transpozone TnI determining ampicillin resistance into the E . coli K-12 chromosome resulted in formation of auxothrophic mutants of 2 types . The mutants of the first type carried thermosensitive mutation resulting in auxotrophy with respect to isoleucine at a temperature of 43 degrees C . Such mutants occurred with high frequency (up to 14 per cent with respect to the number of the survived cells with the chromosomes carrying inserted TnI) and had capacity for reversion to the phenotype of the wild type . The mutants of the second type occurred with a frequency 20--180 times lower than that of the mutants of the first type and did not reverse to the phenotype of the parent bacteria . It was found that the chromosome of E . coli K-12 possessed at least 7 sites available for transpozone TnI insertion.

Biokhimiia, 1978 Sep, 43(9), 1640 - 7
{Effect of mutations in regulatory genes for alkaline phosphatase on the phosphohydrolase spectrum of E . coli periplasm}; Maraeva OB et al.; The isoform spectra of alkaline and acid phosphatase, pyrophosphataes, and ATPase in periplasm of E . coli were studied using electrophoresis in polyacrylamide gel with subsequent development of zimograms directly in the gel . Wild strains and mutants on 4 regulatory genes of alkaline phosphatase were analyzed . Mutations in regulatory genes were shown to influence the amount of each of the 3 isoforms of alkaline phosphatase and also the spectra of other phosphohydrolases.

Cell, 1978 Sep, 15(1), 215 - 29
DNA sequences of promoter regions for the str and spc ribosomal protein operons in E . coli; Post LE et al.; The DNA sequences have been determined for promoter regions of two ribosomal protein operons in E . coli, the str operon and the spc operon . The site of in vitro transcription initiation within each of these promoter regions has been determined . The start site of the str operon occurs 69 bases upstream from the initiation codon of the S12 gene . The start site of the spc operon occurs 72 bases upstream from the L14 gene, and only 91 bases downstream from the termination codon of the S17 gene (which is in the preceding S10 operon) . Both promoters are similar to other sequenced promoters in that they each have an identifiable "Pribnow box" sequence 5 bases upstream from the transcription start site . The spc promoter has a long sequence of 2 fold symmetry centered within the Pribnow box; the str promoter has a shorter but similar symmetry . At positions -69 through -40 in the spc operon, another long region of symmetry is present which may be the termination signal of the preceding S10 operon . Extensive sequence similarity between the str and spc promoter regions is found downstream from the Pribnow box-that is, in a transcribed region preceding the translation start sites.

Diabetologia, 1978 Aug, 15(2), 113 - 6
The effect of E . coli L-asparaginase on oral glucose tolerance and insulin release in man; Lavine RL et al.; To study the effect of E . Coli L-asparaginase on glucose tolerance and insulin release, 6 patients with neoplastic disease were subjected to 3 hour oral glucose tolerance tests with simultaneous measurement of serum immunoreactive insulin (IRI) levels before and following the intravenous administration of 5000 I . U . L-asparaginase/day for 4 days . Five of the patients exhibited a significant deterioration in glucose tolerance; however, no change was noted in their fasting glucose and IRI levels . The deterioration in glucose tolerance was associated with a decrease in the amount of insulin secreted in the first 30 minutes after the oral glucose load . The total amount of insulin released during the 3 hour test remained unchanged . These studies suggest that L-asparaginase can cause a deterioration of glucose tolerance without accompanying fasting hyperglycaemia . This may be due, in part, to a decrease in glucose-induced insulin release during the first thirty minutes following oral glucose.

Acta Pathol Microbiol Scand {B}, 1978 Aug, 86(4), 193 - 9
Phagocytosis of 32P-labelled E . coli by human polymorphonuclear cells (PMN) . Adaptation of a method; Midtvedt T et al.; A system for the study of phagocytosis by human polymorphonuclear cells (PMN) is presented . The leucocytes are harvested from heparinized whole blood by the Boyum method and transferred to glass tubes to yield glass adherent monolayers of leucocytes, approximately 80% of which were PMN . A strain of E . coli labelled by 32P served as test organism.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Aug, 34(2), 101 - 8
The synthesis of DNA by DNA-membrane complexes from irradiated E . coli B/r and Bs-1: the role of the membrane; Robertson WR et al.; DNA-membrane complexes were isolated from lysed E . coli B/r and Bs-1, either by low g forces from a low salt solution, or by high g forces through a discontinuous sucrose gradient . The latter method was more gentle . Irradiation of the intact bacteria had no effect on the membrane macromolecules or on RNA components of these complexes . DNA loss was not significant after irradiation under anoxic conditions but complexes isolated from from Bs-1 irradiated in air showed an appreciable decrease in DNA content . In the presence of the appropriate nucleotide mixture, both 'free' DNA, found in the supernatant fractions, and rapidly sedimented membrane-associated DNA were able to synthesize DNA in the absence of added polymerase . DNA synthesis associated with 'free' DNA was more sensitive to radiation than that associated with DNA bound to the membrane, which appeared to moderate the effects of radiation on new DNA synthesis . It is concluded that the depression of DNA synthesis is primarily a result of irradiation-induced changes on genome-DNA . The interpretation of earlier work from our laboratories that DNA-membrane complexes contained the macromolecular structure which responded to radiation with a high o.e.r . is not supported by the evidence in this work.

Mol Gen Genet, 1978 Jul 4, 162(3), 269 - 75
Mini-chromosomes: plasmids which carry the E . coli replication origin; Messer W et al.; We have isolated plasmids by linking the 5.9 MD EcoRI fragment of E . coli that carries the origin of replication to an EcoRI fragment that carries an amplicillin resistance determinant, but lacks an origin of replication . 3 plasmids of this type, pOC1, pOC2, and pOC3, are described in detail in this report . Although the plasmids have some adverse effect on the growth properties of the host strain, their existence shows that two functioning chromosomal origins can coexist in one cell . Deletions generated from this type of plasmids allow an allocation of the origin of replication of E . coli within a DNA segment less than 0.4 MD in size.

Ann Sclavo, 1978 Jul-Aug, 20(4), 526 - 45
{Characteristic of endotoxin (and haemolysin) for S-, R- and M-forms of the enteropathogenic "E . coli" (author's transl)}; Parnas J et al.; Endotoxins of E . Coli O 149, IN S-, R- and M-forms, were examined in comparison . Gas chromatography showed only quantitative differences in the amount of volatile fatty acids . Electrophoresis of immunsera and bacteriostatic potency of sera, showed the immunogenicity of those 3 endotoxins, in sequence: S leads to R leads to M . Endotoxin of enteropathogenic E . coli O 149 provokes haemorrhagic effects in bones marrow of mice . Endotoxin influences the reticulo-endothelial system (mobilization of immunocytes) . Endotoxin does not provoke any changes in "ligated loop tests'.

Zh Mikrobiol Epidemiol Immunobiol, 1978 Jul, (7), 115 - 8
{Dynamics of biologically active enterotoxin release by E . coli}; Severtsova MK et al.; Accumulation of E . coli enterotoxin in the Finkelshtein's culture medium in growing the cells in a 30-litre reactor was studied . Accumulation of active highly molecular enterotoxin occurred in the course of a 6-hour cultivation of E . coli, strain P-99 (O141: K85ab; K88ab: H4) in the fluid medium under aeration . Oxygen utilization, synthesis and release into the nutrient medium of pyruvic acid, and protein accumulation were observed . The preparation obtained was stable to the lyophylic drying, contained thermolabile and thermostable toxins and marked edema of mouse limbs . The data obtained were of significance for the industrial production of active enterotoxin preparations.

Nucleic Acids Res, 1978 Jul, 5(7), 2289 - 96
Structure determination of a nucleoside Q precursor isolated from E . coli tRNA: 7-(aminomethyl)-7-deazaguanosine; Okada N et al.; A precursor of modified nucleoside Q isolated from E . coli methyl-deficient tRNA was determined to be 7-(aminomethyl)-7-deazaguanosine . The structure was deduced by means of its chromatographic and electrophoretic mobilities, and UV and mass spectra, in addition to comparison with the synthesized authentic compound . The same molecule is also found in tRNA of an E . coli mutant selected for deficient synthesis of modified nucleosides.

Br J Radiol, 1978 Jul, 51(607), 524 - 7
The response of E . coli AB2463 recA to fast neutron beams with mean energies in the range 4 to 27 MeV; Redpath JL; The radiosensitivity of E . coli AB2463 recA, given as the reciprocal of the mean lethal dose, Do-1, has been shown to be the same for four fast neutron beams with widely different energy spectra . It is proposed that this organism can be used to intercompare dosimetry on fast neutron beams with mean energies in the range 4 to 25 MeV with an accuracy of +/- 5%.

Genetics, 1978 Jul, 89(3), 453 - 65
Experimental evolution of a new enzymatic function . II . Evolution of multiple functions for ebg enzyme in E . coli; Hall BG; The evolution of ebgo enzyme of Escherichia coli, an enzyme which is unable to hydrolyze lactose, lactulose, lactobionate, or galactose-arabinoside effectively, has been directed in successive steps so that the evolved enzyme is able to hydrolyze these galactosides effectively . I show that in order for a strain of E . coli with a lacZ deletion to evolve the ability to use lactobionate as a carbon source, a series of mutations must occur in the ebg genes, and that these mutations must be selected in a particular order . The ordered series of mutations constitutes an obligatory evolutionary pathway for the acquisition of a new function for ebgo enzyme . A comparison of newly evolved strains with parental strains shows that when ebg enzyme acquires a new function, its old functions often suffer; but that in several cases old functions are either unaffected or are improved . I conclude that divergence of functions catalyzed by an enzyme need not require gene duplication.

Nucleic Acids Res, 1978 Jul, 5(7), 2665 - 78
In vitro transcription in E . coli crude lysates prepared on cellophane discs; Valla S et al.; An in vitro RNA-synthesizing system consisting of gently lysed E . coli cells on cellophane discs is described . The system has been optimalized with respect to total RNA synthesis . Under certain standard conditions DNA dependent RNA polymerase (EC 2.7.7.6) is responsible for the majority of the RNA synthesis . The extensive rifampicin sensitivity of the synthesis indicates that most of the transcripts are initiated in vitro . The RNA synthesizing system described here has been developed with the aim of studying phage transcription in vitro . We show here that lysates of a P4 infected P2 lysogen support initiation and propagation of transcription from the P2 prophage.

Rev Esp Fisiol, 1978 Jun, 34(2), 159 - 66
The action of inhibitors (histidine and AMP) on the ATP phosphoribosyltransferase of E . coli; Tebar AR et al.; The inhibitors histidine and AMP cause the enzyme ATP phosphoribosyltransferase of E . coli to associate into a hexamer from its initial dimeric form . The behaviour of these inhibitors has been studied by three different methods . I) Equilibrium dialysis studies have shown that one mole of dimeric enzyme (67,000 g) binds one mole of histidine . II) By kinetic inhibition of the reaction studied at 21, 25 and 38 degrees C the enthalpy changes in the process of histidine and of AMP inhibition have been deduced . The inhibition has also been studied in function of enzyme concentration and temperature . The inhibition appears to be slightly negatively cooperative for histidine and positively cooperative for AMP . In neither case is it possible to obtain 100% maximal inhibition . III) By microcalorimetric analysis the values obtained for the enthalpies of histidine and of AMP interaction with the enzyme are similar.

Nucleic Acids Res, 1978 Jun, 5(6), 1845 - 62
Subunit topography of RNA polymerase (E . coli) in the complex with DNA; Okada M et al.; E . Coli RNA polymerase binding to different DNAs (from E . Coli, 5-bromodeoxyuridine (BrdUrd) substituted DNA and poly {d(BrU-A)} was induced with ultraviolet (U.V.) light to form protein-DNA crosslinked complexes . Two independent methods of analysis, polyacrylamide gel electrophoresis in SDS and chloroform extraction indicated the formation of a stable complex between the enzyme and DNA . The complexes were formed under different ionic strength conditions, at low enzyme to DNA ratios in order to approach the conditions of specific binding . In contrast there was no crosslinking of the complex in 1 M KCl solution which dissociates the enzyme from DNA . The efficiency of formation of strongly bound complex was found to be much higher with holoenzyme than with core enzyme . The following results were obtained : 1) The large subunits beta and beta' were found to be bound to DNA . 2) Relatively small amount of sigma subunit were bound to DNA while alpha subunits were essentially not attached to DNA . The high binding affinity of beta and beta' subunits was also observed in the studies of isolated subunits . These results lead to a model of enzyme-DNA complex in which the large beta and beta' subunits provide the contacts between the RNA polymerase and the DNA.

Mol Gen Genet, 1978 Jun 1, 162(1), 9 - 16
A cold sensitive dnaA mutant of E . coli which overinitiates chromosome replication at low temperature; Kellenberger-Gujer G et al.; A heat resistant mutant of E . coli dnaAts46 was isolated, which grows normally only at temperatures above 39 degrees . After a temperature shift from 42 degrees to 32 degrees the mutant overproduces DNA relative to protein . This is due to overinitiation of rounds of chromosome replication at low temperature, as indicated by hybridization and other experiments . The mutation is cotransduced by PI with ilv and could not be separated from dnaAts46 by transduction.

Mol Gen Genet, 1978 Jun 1, 162(1), 109 - 11
Map position of the replication origin on the E . coli chromosome; Fayet O et al.; Strains carrying a dnaA temperature sensitive (t.s.) mutation and a Mu-1 prophage inserted within different genes near the origin of replication have been constructed . For each strain, integratively suppressed Hfrs, named G and D in which the ori region was replicated clockwise and counterclockwise respectively, were isolated . The strand preferences of Mu-1 specific Okazaki fragments were subsequently determined for each t.s . strain and its Hfr derivatives . Their comparison led us to establish the direction of replication of the Mu-1 marker from ori . The site ori was confined to the bglB-C--rbsK-P interval.

Biull Eksp Biol Med, 1978 Jun, 85(6), 718 - 9
{Compatibility of the F-like plasmid FB1drd with standard F-group plasmids in E . coli K12 strains}; Shchipkov VP et al.; Compatibility of depressed F-like plasmid FB1drd integrated into E . coli K12 cell chromosome with standard plasmids of FI-FVI compatibility groups was studied . The results obtained show that such plasmids can stably coexist in the same cell with plasmid FB1drd . On these grounds it is supposed that the latter belongs to the new compatibility group (FVII).

Mol Gen Genet, 1978 May 31, 161(3), 285 - 9
Mutations in the tryptophanyl-transfer ribonucleic acid ligase of E . coli causing temperature-sensitivity for growth; Bohman K et al.; Strains of Escherichia coli K-12 with altered tryptophanyl-tRNA ligases, conferring temperature-sensitivity for growth, have been isolated as spontaneous one-step mutants . The mutated enzymes differ markedly in activity from the wildtype, even at the permissive temperature . When assayed at the non-permissive temperature, the mutant enzymes are completely inactive . In one of the mutant strains, growth can be completely inhibited by addition of L-phenylalanine or L-tyrosine to the medium.

Cell, 1978 May, 14(1), 179 - 90
Patterns of protein synthesis in E . coli: a catalog of the amount of 140 individual proteins at different growth rates; Pedersen S et al.; The amount of 140 individual proteins of E . coli B/r was measured during balanced growth in five different media . The abundance of each protein was determined from its absolute amount in 14C-glucose-minimal medium and a measurement of its relative amount at each growth rate using a double labeling technique . Separation of the proteins was carried out by two-dimensional gel electrophoresis . This catalog of proteins, combined with 50 additional ribosomal proteins already studied, comprises about 5% of the coding capacity of the genome, but accounts for two thirds of the cell's protein mass . The behavior of most of these proteins could be described by a relatively small number of patterns . 102 of the 140 proteins exhibited nearly linear variations with growth rate . The remaining 38 proteins exhibited levels which seemed to depend more on the chemical nature of the medium than on growth rate . Proteins, including the ribosomal proteins, that increase in amount with increasing growth rate account for 20% of total cell protein by weight during growth on acetate, 32% on glucose-minimal medium and 55% on glucose-rich medium . Proteins with invariant levels in the various media comprise about 4% of the cell's total protein.

Antibiotiki, 1978 Apr, 23(4), 337 - 41
{RP4 factor integration with E . coli chromosome}; Danilevich VN et al.; Integration of R-factor RP4 with the chromosome of E . coli was studied with the use of replication thermosensitive mutant pEG1 of this factor . It was found that the frequency of integration of factor pEG1 containing the ampicillin transposone Tn1 with the chromosome of bacteria JC411 carrying transposone Tn1 previously inserted into it was very high and markedly exceeded that of its insertion into the same chromosome but not carrying this transposone . The frequency of factor pEG1 insertion into the chromosome of bacteria JC 1553 rec A defective with respect to genetic recombination was less than 2.10(-5) and did not depend on the presence of transposone Tn1 in it . Probably, insertion of factor RP4 into the bacterial chromosome may be realized through the rec A-dependent process of recombination between transposone Tn1 previously translocated into the chromosome and the same transposone contained in R-factor.

J Biochem (Tokyo), 1978 Apr, 83(4), 1009 - 17
Structure of extracellular polysaccharides of Escherichia coli strains 36M, 72M, and 29M isolated from coligranuloma of chick intestine . I . Polysaccharide from E . coli 36M; Kamei A et al.; An extracellular polysaccharide was isolated from culture broth of Escherichia coli 36M, and fractionated on a column of Sephadex G-150 into two fractions; the high molecular weight portion (85% of the total polysaccharide) contained pyruvic acid, and showed a positive immune reaction with anti-Ps-I-serum obtained from a rabbit . The low molecular weight portion (15% of the total polysaccharide) showed a negative immune reaction . The methylation, Smith's degradation, partial acid hydrolysis and methanolysis of the higher molecular weight polysaccharide revealed a repeating structure as follows: (see article).

Gene, 1978 Apr, 3(2), 135 - 47
Deletions within E . coli plasmids carrying yeast rDNA; Cohen A et al.; Deletions occur in recombinant DNA plasmids that contain yeast ribosomal DNA (rDNA) inserted into the E . coli plasmids pSC101 and pMB9 . Deletions within a pMB9 plasmid containing an insert longer than one tandem rDNA repeat apparently are due to homologous recombination because (1) all of the independently derived deletion products of this plasmid lost one complete rDNA repeat (8.6 kb) and retained only a single copy of the segment repeated at the ends of the original insert and (2) deletions were detected only when the insert had terminal redundancy . Deletions also occur within a pSC101 plasmid containing a tandem duplication of a segment (4.7 kb) including both pSC101 DNA and rDNA . Once again these deletions appear to be due to the presence of a duplicated region because all deletion products have lost one complete repeat . Deletions within both of these plasmids took place in both rec+ and recA- host cells, but occurred more frequently in rec+ cells . Oligomerization of the deletion products also occurred in both hosts and was more frequent in rec+ cells.

Transfusion, 1978 Mar-Apr, 18(2), 149 - 54
Naturally occurring anti-Kell stimulated by E . coli enterocolitis in a 20-day-old child; Marsh WL et al.; Anti-A and anti-K have been found in the serum of a 20-day-old child who had not been transfused but who was acutely ill with E . coli enterocolitis . Both antibodies are IgM proteins . The mother's serum does not contain either antibody and the anti-A and anti-K in the infant's serum are not of maternal origin . Both parents and the child are of the Kell phenotype K-k+ . Stool cultures made from the child yielded E . coli O 125:B15, an uncommon B-variant pathogenic coliform . Cell-free preparations made from broth cultures of this organism have strong specific inhibitory activity against IgM anti-A and anti-K, and both antigens have been identified on the bacterial cells . At age 3 months the child had made a clinical recovery, stool cultures showed no pathogenic coliforms, and anti-A and anti-K were no longer detectable in her serum . These data indicate that absorption of metabolites with A-like and K-like activity produced by a pathogenic coliform in the intestinal tract were responsible for the appearance of apparent naturally occurring anti-A and anti-K in the child's serum.

Nucleic Acids Res, 1978 Mar, 5(3), 925 - 32
Binding of E . coli RNA polymerase to chromatin subunits; Bustin M; Chromatin subunits were prepared from purified rat liver nuclei and the template properties of the nucleosome preparation studied . It was found that: 1) The fundamental template restriction of chromatin (as compared to deproteinized DNA) is retained in the isolated nucleosomes, 2) On the average one molecule of RNA polymerase is bound to one molecule of DNA purified from nucleosomes, 3) The number of RNA polymerase binding sites on chromatin subunits is 6 to 20 times lower than that of the DNA extracted from these subunits, 4) Transcription can proceed through nucleosomes resulting in RNA chains approximately 150 nucleotides long.

Nucleic Acids Res, 1978 Mar, 5(3), 879 - 92
The effect of specific structural modification on the biological activity of E . coli arginine tRNA; Kruse TA et al.; Escherichia coli arginine tRNA1 has been modified at position s2C32 with iodoacetamide and a spin labelled derivative . The small effects on the charging ability of tRNA by the modifiications suggest that the synthetase does not bind to the tRNA in this region of the anticodon loop before the anticodon . A ternary complex of elongation factor Tu, GTP and the modified Arg-tRNA, can be formed allowing future studies of enzymatic binding to the ribosome . Using the triplet binding assay the native Arg-tRNA1 decodes all 4 codons beginning with CG . The modified Arg-tRNA1 has a restricted decoding but the decoding pattern is still unusual according to the Wobble Hypothesis.

Nucleic Acids Res, 1978 Mar, 5(3), 691 - 6
Template specific inhibitors of E . coli RNA polymerase; Chou HJ et al.; Electroneutral analogs of polynucleotides, poly-9-vinyladenine and poly-1-vinyluracil inhibit E . coli RNA polymerase in all combinations where the single stranded polynucleotides are used as templates and the vinyl analogs are complementary to them . As templates both the ribo- and deoxyribopolynucleotides were tested; variation of the template concentration in the presence of vinyl analogs produced a competitive pattern of inhibition . The electroneutral analogs do not inhibit the enzyme activity when non-complementary single stranded polynucleotides or double stranded polynucleotides are used as templates; the latter fully supports transcription even when one of the strands is complementary to the analog.

Nord Vet Med, 1978 Mar, 30(3), 107 - 15
{Evaluation of some methods for study of the pathogenecity and toxicity among enteropathogenic suspect E . coli strains (author's transl)}; Tramsen C et al.; The current methods for testing enteropathogenic E . coli have been revised and slightly modified for use in our laboratory . Their applicability as screening tools in epidemiological surveys is discussed . It is concluded that the current methods for detecting these E . coli in epidemiological surveys are inadequate and laborious and the need for a simple field method is stressed.

J Gen Virol, 1978 Mar, 38(3), 497 - 503
Mitogen induction of murine C-type viruses . IV . Effects of lipoprotein E . coli, pokeweed mitogen and dextran sulphate; Moroni C et al.; Lipoprotein E . coli, a B-cell mitogen, is identified as a new agent inducing the release of endogenous C-type virus from mouse spleen cells . Like lipopolysaccharide, a previously identified inducer, this compound has a synergistic effect with 5-bromo-2'-deoxyuridine . Induced virus has the characteristic density as well as morphology of C-type viruses . Budding viruses are detected on cultured BALB/c cells by electron microscopy 2 to 4 days following culturing in the presence of lipoprotein . Pokeweed mitogen, a compound mitogenic for T- and B-cells was negative when tested for virus induction, both alone and in combination with 5-bromo-2'-deoxyuridine . Dextran sulphate, another B-cell mitogen, was negative for induction as well . However, when, combined with lipopolysaccharide, it enhanced the virus release induced by this mitogen . In contrast, no additive effects were observed either by combining dextran sulphate with other virus amplifying mitogens or by combinations of mitogens which both have virus-inducing ability . This finding is discussed with respect to B-cell differentiation.

Nucleic Acids Res, 1978 Feb, 5(2), 451 - 61
Selective inhibition of uracil tRNA methylases of E . coli by ethionine; Tscherne JS et al.; L-ethionine has been found to inhibit uracil tRNA methylating enzymes in vitro under conditions where methylation of other tRNA bases is unaffected . No selective inhibitor for uracil tRNA methylases has been identified previously . 15 mM L-ethionine or 30 mM D,L-ethionine caused about 40% inhibition of tRNA methylation catalyzed by enzyme extracts from E . coli B or E . coli M3S (mixtures of methylases for uracil, guanine, cytosine, and adenine) but did not inhibit the activity of preparations from an E . coli mutant that lacks uracil tRNA methylase . Analysis of the 14CH3 bases in methyl-deficient E . coli tRNA after its in vitro methylation with E . coli B3 enzymes in the presence or absence of ethionine showed that ethionine inhibited 14CH3 transfer to uracil in tRNA, but did not diminish significantly the 14CH3 transfer to other tRNA bases . Under similar conditions 0.6 mM S-adenosylethionine and 0.2 mM ethylthioadenosine inhibited the overall tRNA base methylating activity of E . coli B preparations about 50% but neither of these ethionine metabolites preferentially inhibited uracil methylation . Ethionine was not competitive with S-adenosyl methionine . Uracil methylation was not inhibited by alanine, valine, or ethionine sulfoxide . It is suggested that the thymine deficiency that we found earlier in tRNA from ethionine-treated E . coli B cells, resulted from base specific inhibition by the amino acid, ethionine, of uracil tRNA methylation in vivo.

Biull Eksp Biol Med, 1978 Feb, 85(2), 150 - 2
{Edema of the paws of white mice--test for assessing the activity of E . coli enterotoxins}; Vartanian IuP et al.; The authors studied the paw edema test in mice for detection of the E . coli (strain P-99) enterotoxins activity . This test proved to be simple, sensitive and reproducible; it permitted to determine the activity of thermostable and thermolabile enterotoxins and endotoxin; the mentioned test was particularly useful in testing various preparations of enterotoxins obtained during their extraction and purification.

Cell, 1978 Feb, 13(2), 335 - 44
Some rRNA operons in E . coli have tRNA genes at their distal ends; Morgan EA et al.; We have previously isolated seven rRNA operons on plasmids or lambda transducing phages and identified various tRNAs encoded by these operons . Each of the seven operons has one of two different spacer tRNA gene arrangements between the genes for 16S and 23S rRNA: either tRNAGlu2 or both tRNAIle1 and tRNAAla1B genes . In addition, various tRNA genes are located at or near the distal ends of rRNA operons . In particular, genes for tRNATrp and tRNAAsp1 are located at the distal end of rrnC at 83 min on the E . coli chromosome . Experiments with various hybrid plasmids, some of which lack the rRNA promoter, have now demonstrated that this promoter is necessary for expression of the distal tRNA genes . Rifampicin run-out experiments have also provided evidence that the tRNATrp gene is located farther from its promoter than the spacer tRNA gene or the 5S RNA gene . These results confirm the localization of genes for tRNATrp and tRNAAsp1 at the distal end of rrnC and strongly suggest that they are co-transcribed with the genes for 16S, tRNAGlu2, 23S and 5S RNA . Other such distal tRNAs have been identified, and it is suggested that they too are part of rRNA operons.

Vet Med Nauki, 1978, 15(8), 82 - 6
{Presence of E . coli bacteria in raw and pasteurized cow's milk}; Gogov I et al.; Investigated for the presence of E . coli-bacteria belonging to the O-groups of dispeptic strains, are 85 samples of raw and 212 pasteurized milk, taken from subsequent departments of the milk-producing industry . Dispeptic E . coli are detected in 11.76 per cent of the samples of raw milk studied, and in 5.18 per cent in those of the pasteurized milk . No coli forms are established in samples, taken directly from the pasteurizing equipment . The secondary infection with E . coli results from the use of vessels and equipment in the course of the technological process . E . coli-bacteria, belonging to the O-groups of dispeptic strains, are demonstrated in samples both with the aid of a coli-titre, in conformity with standard requirements, and in samples that are not standard, according to this indice . The 21 strains of E . coli-bacteria isolated are referred to the following O-groups: 06, 025, 026, 055, 078, 086, 0111, 0119, 0124, 0125 and 0127 . Some of the strains isolated manifest an atypical behaviour to lactose and sucrose in comparison with the properties, indicated in the scheme by Kauffmann.

Microbios, 1978, 21(83), 41 - 6
Stability and maturation of E . coli ribosomal RNA; Andersen O; The kinetics of rRNA maturation were investigated in a rifampicin permeable strain of E . coli during exponential growth in glucose minimal medium . The method used involves isotopic labelling of rRNA, and separation of precursor and mature forms by gel electrophoresis . The maturation of both 16s and 23s rRNA was found to follow first order kinetics . The mean life time of the precursors was found to be about 1.5 min . In glucose minimal medium all pulse label in precursors was recovered in mature rRNA, i.e . nascent rRNA is stable.

Acta Biol Med Ger, 1978, 37(9), 1489 - 98
{Laboratory experiments with a polyvalent extract vaccine for oral immunization against E . coli enteritis}; Austenat L et al.; Bacteria of E . coli causing enteritis can be extracted by EDTA-sodium . These extracts having lower dry weights result in better protective effects in contrast to sodium-deoxycholate extracts . The EDTA-sodium extracts can be concentrated, purified and sterile filtrated . Thus the production of polyvalent vaccines is possible . A direct relation exists between the effectiveness of the extracts and the virulence of the strains used for extraction . The more virulent the original strain the better is the protective effect of the vaccine produced by extraction of the original strain . The single components of the polyvalent vaccine show a certain improvement of their protective effects . For estimating the immunizing dose, it is necessary to consider the limiting dose . When exceeding this dose the protective effect or the vaccine does not further increase but remains constant of even decreases . The immunizing dose wanted must be greater than the ED50 but smaller than the limiting dose . Extremely high oral doses of vaccine result in symptoms of incompatibility in mice.

J Hyg Epidemiol Microbiol Immunol, 1978, 22(3), 328 - 37
Enterotoxigenic E . coli in humans; Blaha R et al.; E . coli strains isolated from persons having diarrhoeal disease were tested for the production of TS enterotoxin . The production of TSE was demonstrated in 2.5% in a series of 80 strains isolated from children under one year of age, having acute diarrhoea . TSE was produced by 8.4% of E . coli strains out of 59 strains isolated from patients over one year of age . Among these strains, an interesting E . coli strain was isolated from the patient T . J., which produced TSE for more than 15 months . The production of TLE was tested though not proved in all strains by experiment on an isolated intestinal loop of an adult rabbit . The test on suckling mice so far appears to be the most suitable test for the demonstration of TSE . The results were considered positive when the index (the ratio of the weight of the whole intestine to the weight of the rest of the body) was higher than 0.08 while indices up to 0.078 were considered negative . E . coli strains with indices of intermediate values and strains with temporary production of TSE, occurring particularly in very small children, deserve special attention . The height of the indices was not influenced by a 30-minute exposure at 60 degrees C, but a decrease in the values of the indices was observed after boiling for a period of 15 min . The occurrence of E . coli strains producing TSE is evidently small in humans in European countries but, without doubt, they are important in the aetiology of diarrhoeal diseases.

Vet Med Nauki, 1978, 15(3), 64 - 8
{Transmissible drug resistance in E . coli isolated from calves}; Kokosharov T; The study of 30 strains of Escherichia coli, isolated from calves on various farms of the district of Haskovo, revealed that 70.0% of them manifested resistance to drugs . The capacity of calf E . coli organisms of being donors of resistance factors pointed to the episomal nature of their polyresistance . The comparatively readily effected transmission of drug resistance from E . coli isolated from calves was shown to be potential clinical and epizootic hazard . Such animals proved to be carriers and a source of R+ Escherichia coli organisms . It was found that the transmission of drug resistance was not coupled with the transmission of chromosomal inheritance . A high frequency of the drug-resistance transmission phenomenon was established.

Circ Shock, 1978, 5(3), 271 - 8
In vitro effects of methyprednisolone sodium succinate and E coli organisms on neutrophils in baboon blood; Hinshaw LB et al.; The corticosteroid methylprednisolone sodium succinate (MP) has been observed to prevent hypoglycemia in experimental septic shock; however, detrimental actions of various corticosteroids on polymorphonuclear leukocyte function have been reported . The present study was designed to determine if MP depresses glucose metabolism of leukocytes or adversely affects neutrophil survival, or whether it modifies the mortality rate of live E coli in baboon blood in vitro . Results show that therapeutically effective concentrations (13 micrograms/ml blood) and high doses (130 micrograms/ml blood) of MP exert no detrimental influences on glucose utilization or survival of neutrophils in the absence or presence of E coli organisms in concentrations of 4.2 x 10(7) and 2.3 x 10(8) organisms per milliliter blood . However, E coli organisms increase neutrophil mortality rate and glucose uptake of the blood . These findings support the view that MP does not adversely influence leukocyte metabolism and survival, nor does it modify the mortality rate of live E coli.

Clin Exp Immunol, 1978 Jan, 31(1), 104 - 10
The natural antibody response to E . coli includes antibodies of the IgD class; Sewell HF et al.; Antibodies to E . coli of the IgM, IgG and IgA class are readily demonstrable in normal human serum . Using the sensitive red cell-linked antigen-antiglobulin system, it has been demonstrated that antibodies of the IgD class are also part of this normal response . The IgD antibody titre is low and often could only be demonstrated in partially purified IgD preparations . The availability of purified IgD paraproteins and their Fabdelta and Fcdelta fragments, as well as antisera specific for these fragments, allowed the necessary critical specificity controls to be performed.

Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 427 - 31
Mutation affecting thermostability of sigma subunit of Escherichia coli RNA polymerase lies near the dnaG locus at about 66 min on the E . coli genetic map; Gross C et al.; The Escherichia coli strain, ts-rnp5, originally described in 1975 by G . D . Burdick and H . Berger, is shown to possess an RNA polymerase (RNA nucleotidyltransferase) sigma subunit with an activity 4--6 times less thermostable at 45 degrees than sigma from wild-type strains . This defect remains associated with the sigma polypeptide through a variety of purification stages, including renaturation of sigma after its elution from sodium dodecyl sulfate/polyacrylamide gels . The mutation responsible for decreased thermostability of sigma, called rpoD1, cotransduces with dnaG and therefore is located at about 66 min of the E . coli genetic map.

Biokhimiia, 1978 Jan, 43(1), 180 - 3
{Translation of poly U by ribosomes from rel+ and rel- E . coli strains}; Drobyshev VI et al.; A translation of polyU in a cell-free system from CP78 (relA+) and CP79 (relA-) E . coli strains is investigated . The strains studied no not differ in misreading at Mg2+ concentration of 20 mM and concentrations of 16 mM (optimal for phenylalanine incorporation) and 18-22 mM (optimal for leucine incorporation) respectively . It is found that leucine incorporation increases similarly in both strains under conditions simulating an amino acid deficience (in phenylalanine-free incubation medium): the ratio leucine(-phenylalanine)/leucine (+phenylalanine) is 3.5-4 at a concentration of enzymatic fraction protein being 15-30 mkg per example, and it is 2 st a concentration of enzymatic fraction of 60-180 mkg of protein . It is suggested that differences in activities of a number of enzymes under amino acid starvation in Rel+ and Rel- cells are not due to differences in the precision of mRNA translation, but depend on the activity of respective genes.

Ann Rech Vet, 1978, 9(3), 441 - 51
Scanning electron microscopy of abomasium and intestine of gnotoxenic calves infected either with rotavirus, coronarivus or enteropathogenic Escherichia coli or with rotavirus and E . coli; Dubourguier HC et al.; Neonatal calf diarrhoea induced with several agents of infection was studied by scanning electron microscopy . In a gnotoxenic calf infected with E . coli K99+ Ent+, slight lesions of the small intestine were observed and desquamation or puffiness of microvilli occurred . In rotavirus-infected calves, the abomasum was covered with abudant mucous film and appeared to be desquamated . In the small intestine, no desquamation of epithelium was observed . Inoculation of the rotavirus and E . coli induced severe diarrhoea . The whole digestive tract, even the abomasum and colon, was eroded . Coronavirus induced marked lesions in all levels of the intestine . These results demonstrate unequivocally the pathogenic properties of the three infectious agnets, the synergistic effect of E . coli and rotavirus . Furthermore, the importance of the abomasum in neonatal diarrhoea is emphasized.

Ann Rech Vet, 1978, 9(3), 433 - 40
The experimental production of diarrhoea in colostrum deprived axenic and gnotoxenic calves with enteropathogenic Escherichia coli, rotavirus, coronavirus and in a combined infection of rotavirus and E . coli; Gouet P et al.; We attempted to produce diarrhoea experimentally in the newborn calf by orally injecting 17 colostrum-deprived calves with two serotypes of Escherichia coli Ent+ K99+, a rotavirus and a coronavirus . With E . coli alone, a dose of 2 x 10(8) bacteria administered 24 hours after birth causes a mild attack of diarrhoea, whereas 1 x 10(10) bacteria leads to dehydration and death . An inoculation of rotavirus is followed by diarrhoea which always contains large quantities of rotavirus . These animals were anorectic for a time, but none was dehydrated or died . With coronavirus, there were large quantities of watery diarrhoea, which led to dehydration and death . The inoculation of rotavirus, not lethal in itself, followed by a similarly non lethal inoculation of E . coli in doses of 3 x 10(8) to 2 x 10(9) led to dehydration and death . The authors conclude that dehydration and death of the animal can caused by large doses of E . coli or coronavirus or by two non-lethal doses of rotavirus and E . coli administered one after the other.

Arch Invest Med (Mex), 1978, 9 Suppl 1, 113 - 6
{Ultramicroscopic structure of the cyst wall of Entamoeba invadens, E . histolytica and E . coli}; Chavez B et al.; The ultrastructure of the wall of E . invadens cysts induced in axenic cultures was compared by transmission electron microscopy of thin sections, with that of E . histolytica and E . coli cysts obtained from feces of human asymptomatic carriers . The cyst wall of the three species studied had similar ultrastructural features; in all, the wall was composed mainly by the aggregation of filaments adjacent to the plasma membrane . The cytoplasmic components which might be involved in the synthesis and deposit of the cyst wall of E . invadens appear to be different to those of E . coli and E . histolytica cysts.

Z Naturforsch {C}, 1978 Jan-Feb, 33(1-2), 61 - 4
Inhibition of Mg, Ca-ATPase from E . coli by ruthenium red; Scherr F et al.; The membrane-bound, solubilized, and trypsin-treated forms of Mg, Ca-ATPase from E . coli are inhibited by ruthenium red {RR} . The inhibition is noncompetitive and is reduced at higher substrate concentrations . n-Butanol-extracted ATPase is not inhibited by ruthenium red and is not activated by KCl.

Scand J Gastroenterol, 1978, 13(3), 277 - 81
Fluorescent anti-colonic and E . coli antibodies in ulcerative colitis; Marcussen H; With the indirect immunofluorescence technique using sections of colon from guenon and rat, sera from patients with ulcerative colitis yielded positive staining of goblet cells . Eight sera, thus defined positive, two negative, and five from hospital controls, were applied to agar preparations of 12 different E . coli strains, normally found in human bacterial diseases and E . coli 0 14 . With E . coli 0 group antigens, 2, 8 and 14 positive fluorescence reactions were regularly found in sera where positive immunofluorescence reaction aginst colon antigen could be demonstrated, indicating that antigen(s) from colon mucosa shares antigenic determinant(s) with some E . coli bacteria or bacterial components.

Circ Shock, 1978, 5(4), 423 - 37
Prolonged shock in the baboon subjected to infusion of E . coli endotoxin; Coalson JJ et al.; This study was designed to examine the response of the baboon during a 24-hour period following Escherichia coli endotoxin infusion . Experiments were conducted on young adult baboons, unrestrained and maintained at a light plane of anesthesia induced with pentobarbital sodium . Light and electron microscopic studies on lung, heart, liver, and kidney were conducted; hematologic changes and physiologic responses were measured . The efficacy of heparin to prevent the coagulopathy and increase survivability was assayed . Hepatic sinusoidal fibrin thrombi with underlying hepatocyte cellular damage was seen in the endotoxin-treated group . In contrast, the experimental group receiving heparin showed no sinusoidal fibrin thrombi but demonstrated hepatocellular damage . Liver dysfunction was indicated by elevation of blood levels of enzymes . Glomerular fibrin thrombi were not present . Although heparin prevented the formation of hepatic thrombi in endotoxin-treated baboons, it did not increase survival . Platelet and complement levels decreased in both experimental groups, while wide variations in white blood cell and fibrinogen levels were observed . Polymorphonuclear leukocyte-platelet aggregations previously reported in the pulmonary vasculature during acute shock were not observed in the present study, and their absence may have been related to the longer time of survival.

C R Seances Soc Biol Fil, 1978, 172(6), 1079 - 84
{Guanylate cyclase in E . coli . III . Purification and possible physiological role of GTPase}; Rocino A et al.; A phosphohydrolase with a preferential activity for GTP has been isolated and partially purified from E . coli extracts . The enzyme purification has been achieved through precipitation by ammonium sulfate and chromatography on DEAE-cellulose, DEAE-Sephadex, Ultragel and a second DEAE-cellulose column . The phosphohydrolase activity is poly (C) dependent . The chromatographic analysis on PEI-cellulose has shown that the main product of GTP hydrolysis is GDP . The possibility that the enzyme partially purified in this work has an important role in the control of GTP availability as substrate for guanylate cyclase into the cells has been discussed.

Physiol Chem Phys, 1978, 10(5), 415 - 34
A new analytical procedure for two-dimensional electrophoresis of cellular proteins: comparison of protein compositions of parent strain and a K+-accumulation mutant of E . coli; Siemankowski RF et al.; An improved two-dimensional analytical electrophoretic technique fractionates according to molecular weight in the presence of dedecyl sulfate in the first dimension, then fractionates according to isoelectric point in a perpendicular dimension . Electrofocusing in the second dimension achieves nearly complete removal of most protein components while providing true estimates of their isoelectric points . Because not all proteins penetrate isoelectric focusing gels, some proteins may go unrecognized using conventional two-dimensional systems where isoelectric focusing precedes electrophoresis . However, such components do enter dodecyl sulfate gels; hence the presence and molecular weight of those components can be established by the new procedure . A concurrent finding was that, in general, penetration of isoelectric focusing gels by discrete protein subunits dissolved in 9 M urea is an all-or-none phenomenon depending on the solubility of the specific subunit . The procedure was applied to comparison of the protein compositions of a parental strain (CBH) of Escherichia coli and a derived mutant strain (RD-2) deficient in ability to accumulate K+ . The strains showed similar two-dimensional patterns except for one discrete isoelectric component absent in the parent strain but present in the mutant.

Mol Gen Genet, 1977 Dec 9, 157(3), 301 - 11
Interaction of E . coli RNA polymerase with promotors of coliphage T5: the rates of complex formation and decay and their correlation with in vitro and in vivo transcriptional activity; von Gabain A et al.; The genome of virulent coliphage T5 contains about 30 sites which form stable complexes with E . coli RNA polymerase . Some of these sites bind RNA polymerase with high rates, others form extremely stable complexes as compared with promotors of other E . coli systems . The transcriptional activity of these promotors in vivo and in vitro reflects the rate of complex formation with RNA polymerase rather than the stability of the enzyme/promotor complex . The fastest, i.e . the most active promotors are found in the "early" region of gene expression followed by promotors of the "preearly" class . The few binding sites for the E . coli holoenzyme within the "late" region react more slowly with the enzyme.

Nucleic Acids Res, 1977 Dec, 4(12), 4063 - 75
Detection of nucleoside Q precursor in methyl-deficient E.coli tRNA; Okada N et al.; 32P-Labeled tRNAAsn was isolated from methyl-deficient E . coli tRNA . Nucleotide sequence analysis showed that tRNAAsn contains three derivatives of the Q nucleoside, possibly Q precursors, in addition to guanosine in the first position of the anticodon . One of the Q precursors was isolated on a large scale . Its UV spectra were identical with those of normal Q, indicating that 7-deazaguanosine structure having a side chain at position C-7 is complete in the Q precursor . No radioactivity was incorporated into Q or Q precursors from either {methyl-14C}methionine, {1-14C}methionine or {U-14C}methionine, showing that methionine was not directly involved in the formation of Q.

Mol Gen Genet, 1977 Nov 29, 157(1), 1 - 9
An adaptive response of E . coli to low levels of alkylating agent: comparison with previously characterised DNA repair pathways; Jeggo P et al.; We have described previously an inducible response in Escherichia coli which occurs during growth on low levels of the methylating agent, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and which enables cells both to survive better and to be less mutated by a subsequent challenge dose of MNNG than control cultures (Samson and Cairns, 1977) . We show here that this response is distinct from previously characterised pathways of DNA repair, and particularly from the SOS response, which is another inducible effect resulting from DNA damage . An examination of the cross-reactivity of this response with other mutagens has shown that it is a generalised mechanism affecting alkylation damage to DNA . It cannot, however, be induced by UV or the UV-mimetic mutagen, 4-nitroquinoline 1-oxide, nor act on lesions put into DNA by those mutagens.

Mol Gen Genet, 1977 Nov 29, 157(1), 99 - 107
DNA synthesis and degradation in UV-irradiated toluene treated cells of E . coli K12: the role of polynucleotide ligase; Strike P; Toluene treated cells have been used to study the processes of DNA synthesis and DNA degradation in ultra-violet irradiated Escherichia coli K12 . Synthesis and degradation are both shown to occur extensively if polynucleotide ligase is inhibited, and to occur to a much lesser extent if ligase activity is optimal . Extensive UV-induced DNA synthesis in toluene-treated cells requires ATP for the initial incision step, and DNA polymerase I . Extensive degradation also depends on the early ATP-dependent incision step, and the subsequent degradation shows a partial requirement for ATP . Curtailment of degradation by ligase requires DNA polymerase activity, but is not dependent upon DNA polymerase I . Apparently this process can be carried out with equal facility by either DNA polymerase II or polymerase III . These observations suggest that extensive DNA polymerase I-dependent repair synthesis and extensive DNA degradation are facets of two divergent pathways of excision repair, both of which depend upon the early uvrABC determined ATP-dependent incision step.

Biull Eksp Biol Med, 1977 Nov, 84(11), 623 - 6
{Formation of recombinants of F' plasmids in recombination-defective E . coli cells and their properties}; Pekhov AP et al.; As a result of mating of cells carrying plasmid F' lac with cells carrying plasmid F'his merodiploids carrying plasmid complex F'lacF'his were isolated . The plasmid genes of the isolated merodiploids are donated together into the recipient cells and are eliminated jointly from host-cells both spontaneously and by acridine orange . As the formation of the plasmid complex took place in E . coli cells carrying mutation in rec A gene the recombination of plasmids F' is supposed to take place in the absence of the product of gene rec . A.

Acta Paediatr Scand, 1977 Nov, 66(6), 705 - 8
Antibody production by the mammary gland in mothers after artificial oral colonisation of their infants with a non-pathogenic strain E . coli 083; Lodinova R et al.; Twenty five breast-fed and 25 formula-fed infants were colonised by oral administration of a living suspension of E . coli 083 . Twenty breast-fed and 13 formula-fed infants were followed as controls . Specific antibody titres in serum, stool filtrates and milk, and secretory IgA levels in stool filtrates and milk were determined in samples taken fortnightly from birth until 20 weeks of age . The haemagglutinating antibody in serum and milk increased in the colonised groups, but in stool filtrates an inhibitory effect of breast-milk was demonstrated . Secretory IgA levels in stool filtrates were significantly higher in colonised infants and breast-fed controls than in bottle-fed infants during the period of breast feeding . Then levels in the colonised groups remained high, but in breast-fed controls they decreased to values found in bottle-fed controls . Artificial colonisation evoked local antibody and secretory IgA responses in the intestine, as well as an antibody response in the mother's mammary gland . The possible protective effect of those responses is discussed.

Mol Gen Genet, 1977 Oct 24, 155(3), 267 - 77
Defective excision and postreplication repair of UV-damaged DNA in a recL mutant strain of E . coli K-12; Rothman RH et al.; The mutation recL152 leads to a reduction of excision repair as measured by an increase in the time required to close uvrA uvrB dependent incision breaks, and by a reduction of host cell reactivation ability . Postreplication repair is also delayed when measured in a uvrB5 recL152 double mutant . Such a determination could not be made using the recL152 single mutant because the excision defect led to an accumulation of breaks in the unlabeled high molecular weight DNA to which the labeled DNA synthesized after irradiation must attach in order to achieve normal high molecular weight . Further, the recL gene product seems to be required to rejoin breaks in parental strand DNA which are generated during postreplication repair, since such gaps accumulate in a recL152 uvrB5 double mutant but not in a recL+ uvrB5 single mutant . We have noticed a striking phenotypic similarity between recL152 and polA1 and suggest that recL152 is required for full in vivo activity of DNA polymerase I.

Clin Exp Immunol, 1977 Oct, 30(1), 154 - 9
Interstitial nephritis in rats produced by E . coli in adjuvant: immunological findings; Sherlock JE; An increased incidence and severity of interstitial nephritis was produced in F344/fmai rats immunized with E . coli 022 in pertussis vaccine for 12-15 months . Migration of peritoneal exudate cells from immunized animals was inhibited by syngeneic kidney antigens . One out of twenty-eight immunized animals developed anti-TBM antibodies . In this model, interstitial nephritis develops in association with cell-mediated immunity to kidney tissue.

Int J Biomed Comput, 1977 Oct, 8(4), 283 - 91
Potential of the amino acid homology studies: homologies found between beta-galactosidase and lac repressor of E . coli; Erhan S et al.; Significant amino acid homologies were found between beta-galactosidase fragments and lac repressor of E . coli using a sliding match according to Greller and Erhan (1974) . Since both of these proteins can recognise and bind galactose moiety, we propose that the homologous regions represetn galactose binding site(s) on both proteins . Possible application of homology studies to problems of protein and nucleic acid chemistry is also discussed.

Nucleic Acids Res, 1977 Oct, 4(10), 3401 - 14
Pathway-dependent refolding of E . coli 5S RNA; Weidner H et al.; The refolding of 5S RNA into its two conformational states has been examined as a function of solvent composition and annealing conditions . The results show that the product distribution depends on the folding pathway . Quick cooling from high temperature produces roughly equal amounts of the two forms, even in the presence of 1 mm Mg++ . However annealing by slow cooling to intermediate temperatures (50 degrees--60 degrees C) in Mg++-containing buffers, followed by quick cooling, allows formation of a structure which guides the refolding path to the "native" conformation . The stability of this structural nucleus for the "native" conformation depends strongly on Mg++ concentration . We conclude that the A ("native") conformation differs from the B conformation not in rate of refolding, but rather in having a lower enthalpy and a also a smaller rate of unfolding for the critical structural nucleus . The order of folding during biosynthesis may be crucial for forming the "native" conformation.

Br J Pharmacol, 1977 Oct, 61(2), 175 - 81
Modification, by aspirin and indomethacin, of the haemodynamic and prostaglandin releasing effects of E . coli endotoxin in the dog; Fletcher JR et al.; 1 Dogs treated with aspirin (10 mg/kg) or indomethacin (1.5 mg/kg) 45 min before, and 3 h after, an LD50 dose (1 mg/kg) of E . coli endotoxin were alive 72 h later . 2 Although all dogs in both treated groups survived, only those treated with indomethacin were protected against the fall in blood pressure 1-2 min following endotoxin . 3 Endotoxin increased the level of prostaglandin F2alpha in both the mixed venous and arterial blood . No increase was observed in the aspirin and indomethacin-treated groups . 4 Aspirin and indomethacin treatment did not modify thrombocytopaenia or blood coagulation parameters following endotoxin.

Biokhimiia, 1977 Oct, 42(10), 1791 - 9
{Phospholipid composition of E . coli cells and membranes under repression and derepression of alkaline phosphatase biosynthesis}; Evdokimova OA et al.; Lipid composition of E . coli membranes and cells in conditions of repression, derepression and constitutive synthesis of alkaline phosphatase is studied . The identity of qualitative composition of phospholipids and neutral lipids in these conditions is demonstrated . Derepressed and constitutive enzyme syntheses are correlating, a certain increase of phosphatidylglycerol in the total phospholipid pool being more pronounced in cells, than in membranes . The enzyme synthesis correlates also with the increase of 14C-label incorporation into lipids.

Cell Differ, 1977 Oct, 6(3-4), 253 - 62
RNA synthesized in vitro by calf thymus RNA polymerase III (C), as well as by E . coli RNA polymerase, is restricted to a subset of calf thymus DNA; Atikkan EE et al.; RNA synthesized in vitro from chromatin and DNA by calf thymus RNA polymerase III was evaluated by hybridization in vast DNA excess . The RNA contains RNA complementary to both moderately repeated and unique DNA sequences . Very highly repeated DNA is not transcribed . A greater portion of RNA transcribed from DNA by RNA polymerase III hybridizes to moderately repeated DNA than RNA transcribed by Escherichia coli RNA polymerase . In studies utilizing DNA absorbed to filters, RNA transcribed from chromatin in short incubations hybridized to a greater extent than RNA transcribed for longer times . Similar results were obtained with RNA transcribed from DNA by E . coli RNA polymerase . These results suggest: 1) RNA polymerase III may be responsible for the synthesis of RNA species in addition to tRNA and 5 S ribosomal RNA and a portion of this RNA is transcribed from unique DNA; and 2) in vitro there may be selectivity in the initiation of transcription by both E . coli RNA polymerase and calf thymus RNA polymerase III.

Can J Biochem, 1977 Oct, 55(10), 1019 - 27
Identification of a coenzyme A--glutathione disulfide (DSI), a modified coenzyme A disulfide (DSII), and a NADPH-dependent coenzyme A--glutathione disulfide reductase in E . coli; Loewen PC; The nucleotides DSI and DSII induced during a slowdown in growth of E . coli have been characterized using chemical and biochemical analysis and by enzymic and alkaline fragmentation . DSI consists a coenzyme A and glutathione joined by a disulfide linkage . DSI could be isolated either containing Fe(III) with an A250:260 ratio of 1.05 or not containing iron with an A250:260 of 0.87 . DSII (isolated in 10% the yield of DSI) is a coenzyme A disulfide dimer that also contains two molecules of glutamic acid . DSI was a substrate for NADPH-dependent CoAS-SG reductase (EC 1.6.4.6) which was present in crude extracts of E . coli . The specific activity of CoAS-SG reductase increased during growth from early log phase into stationary phase and during a shift from aerobic to anaerobic growth.

J Nucl Med, 1977 Oct, 18(10), 1032 - 4
Iodinated E . coli 70S ribosomes as a radiocolloid of uniform particle size for lymph-node and liver scanning; Chan AS et al.; As an example of the use of biologic particles as carriers for radioactive tracers, E . coli 70S ribosomes were labeled with I-125 using chloramine-T . The labeled ribosomes, after treatment with glutaraldehyde, were injected into rabbits either subcutaneously (through the dorsum of the foot) or intravenously (through the ear) . After subcutaneous injection, 40% of the activity accumulated in the lymph nodes during the first 5 hr, and the 70S ribosomal particles were shown to remain within the lymphatic system for at least 8 hr . After intravenous injection, 71% of the activity was detected in the liver within minutes by scintigraphic techniques . The effective half-time of the label in the liver from glutaraldehyde-treated I-125-tagged 70S ribosomal colloidal particles is 4-5 hr . No pyrogenic response was observed . Barring any deleterious side effects, the results indicate that biologic cell components of definite dimensions (in this case E . coli 70S ribosomes about 20 nm in diam) could be considered as radiocolloids for lymph-node and liver imaging.

Cell, 1977 Oct, 12(2), 521 - 8
A possible involvement of cya gene in the synthesis of cyclic guanosine 3':5'-monophosphate in E . coli; Shibuya M et al.; Based on the following genetical experiments, the cya gene in E . coli was shown to be involved in the synthesis of both cyclic AMP and cyclic GMP . First, all five independent cya-deficient mutants accumulated exceedingly low amounts of cyclic GMP . Second, the ability to form both cyclic AMP and cyclic GMP was simultaneously restored by transduction of an intact cya locus to one of the above cya-deficient mutants . Third, a spontaneous revertant from one of the above mutants regained the synthetic activity for cyclic GMP as well as for cyclic AMP . Fourth, the characteristic of a strain overproducing cyclic GMP was co-transduced with the cya locus . These results suggest that the synthesis of both cyclic GMP and cyclic AMP is mediated by the same enzyme, adenylate cyclase, Interestingly, a reciprocal effect of glucose starvation was observed on the accumulation of both cyclic nucleotides . The formation of cyclic AMP was greatly enhanced on glucose starvation, whereas that of cyclic GMP proceeded at a slower rate than in the presence of glucose . This effect was observed only in cells carrying normal cya and crp genes, but not in a cya-altered or a crp-deficient strain.

C R Acad Sci Hebd Seances Acad Sci D, 1977 Sep 12, 285(4), 435 - 8
{Initiation of transcription and translation in E . coli nucleoids}; Simon MC et al.; The initiation of both transcription and translation occurs in membrane-associated nucleoid of E . coli without the addition of cytoplasmic fraction . Initiation of translation, however, is stimulated by adjunction of S 165 . Our results suggest that the system is limited in synthesizing F-met-tRNA . The capacity of nucleoid-extracted ribosomes to form initiation complexes is only slightly higher than that of supernatant ribosomes . RNA synthesis is partially rifampicin-sensitive, which implies that initiation of new chains takes place in our system.

Zh Mikrobiol Epidemiol Immunobiol, 1977 Sep, (9), 134 - 6
{Detection of F-like plasmids in serologically typed E . coli by the reactions of the donor-specific phage titre increase}; Shchipkov VP et al.; The authors studied 130 strains of serologically typed E . coli for the capacity to provide reproduction of donor-specific phages MS2, Qbeta, and f1; positive increase of the donor-specific phages reaction was found in 12 cases . Some of the detected L-like plasmides bore determinants of colicinogenicity or drug resistance . Such plasmides were transmissive and capable of inhibiting donor properties controlled by factor F'-lac+, i.e . they served as plasmides of type fi+.

Vopr Med Khim, 1977 Sep-Oct, 23(5), 622 - 9
{Effect of methylcobalamin and fluoralkylcobalamins on E . coli 113/3 cell growth and on a primary human embryonic fibroblast culture}; Miasishcheva NV et al.; Comparative analysis of the functional activity of several fluoralkylcobalamines was carried out using E . coli 113/3 strain deficient in vitamin B12 and methionine . Difluoro chlor methylcobalamine (CF2Cl-Cbl) exhibited the most distinct inhibitory effect on growth of bacterial cells in the medium with cobalamine . Effect of methylcobalamine and CF2Cl-Cbl on the proliferative activity of human embryonal fibroblasts was studied in media of various composition . The proliferative activity of fibroblasts was distinctly increased in the medium with methylcobalamine at various periods of cultivation; the fraction of 3H-thimidine labelled cells and the mitotic index were increased . The distinct decrease in amount of cells, synthesizing DNA, and in their mitotic activity was observed in medium with CF2Cl-Cbl . The data obtained suggest that difluorochlor methylcobalamine affects the cell proliferation as the antagonist of methylcobalamine in experiments with bacterial cells and the primary culture of human embryonal fibroblasts.

Boll Ist Sieroter Milan, 1977 Sep, 56(4), 299 - 302
Effects of tilorone hydrochloride on cellular immunity (leukocyte inhibiting factor production from human lymphocyte stimulated by E . coli lipopolysaccharide); Jirillo E et al.; Tilorone hydrochloride, a drug able selectively to affect T-lymphocyte fuction, when incorporated (at three different concentrations 0.1, 0.04, 0.02 microgram/ml) in lymphocyte culture, stimulated by 50 microgram/ml of E . coli LPS (026:B6 W), is able to abolish LIF production, due to endotoxin stimulation . Such effect is, may be, due to an impairment of T-cell activity, since tilorone at the same concentration decreases the number of ARFC and TRFC, which are specific markers for T-cells.

Experientia, 1977 Aug 15, 33(8), 1031 - 2
Correlation between the susceptibility of E . coli to phagocytosis and their ability to invade HeLa cells in vitro; Cian F et al.; The susceptibility of several strains of E . coli to phagocytic killing by polymorphonuclear lencocytes and the ability of the same strains to invade HeLa cells were studied . It was found that only the strains resistant to killing by leucocytes were able to penetrate and multiply within HeLa cells.

Experientia, 1977 Aug 15, 33(8), 1014 - 6
Spin label studies of ATP phosphoribosyltransferase of E . coli; Tebar AR et al.; Covalently bound bromoacetamide nitroxides have been used to detect the conformational changes and enzyme association induced by its feedback inhibitor, histidine.

Experientia, 1977 Aug 15, 33(8), 1029 - 30
Heterologous mischarging as a means of tRNA fractionation . II . Isolation of E . coli tRNA1Val and tRNA1Ala; Leon G et al.; Highly purified E . coli tRNA1Val and tRNA1Ala have been isolated, based on the properties of heteroaminoacylated tRNAs and their behaviour on BD-cellulose chromatography.

Experientia, 1977 Aug 15, 33(8), 1016 - 8
Interaction of extrinsic fluorescent probes with E . coli glutamine synthetase; Wedler FC et al.; Binding of 2-p-toluidinylnaphthalene-6-sulfonate (TNS) to adenylylated (E--11) glutamine synthetase is cooperative and time-dependent, with 3 dye sites per subunit . In fluorescence polarization experiments TNS and pyrene butyrate give normalized Perrin plots that indicate a symmetrical arrangement of dye excited state dipoles, relative to the rotational axis of the oblate ellipsoid of the dodecameric native enzyme.

Cell, 1977 Aug, 11(4), 763 - 77
Sequence arrangement of tRNA genes on a fragment of Drosophila melanogaster DNA cloned in E . coli; Yen PH et al.; A plasmid with the vector Col E1 attached to an insert of Drosophila melanogaster DNA carrying four tRNA genes has been cloned in E . coli . Some features of the sequence arrangement and the positions of the tRNA genes have been determined by electron microscopic methods and by restriction endonuclease mapping . tRNA genes were mapped at 1.4, 4.7, 5.9 and 8.6 kb from one of the Drosophila/Col E1 junctions in the Drosophila insert of total length 9.34 kb . There are several secondary structure features consisting of inverted repeat sequences of length about 70-100 nucleotide pairs, some with and some without intervening loops, irregularly distributed on the insert . Cross-hybridization of tRNAs isolated by hybridization to separated restriction fragments indicate that the tRNA genes at 4.7, 5.9 and 8.6 kb are identical and differ from the one at 1.4 kb . Thus the positions of the genes, of the secondary structure features and of the restriction endonuclease sites all indicate that the spacers between the genes are not identical tandem repeats . In situ hybridization with cRNA transcribed from the plasmid showed localization at region 42A of chromosome 2R.

Biull Eksp Biol Med, 1977 Aug, 84(8), 181 - 2
{Antigenic properties of genetic recombinants of serologically typed E . coli}; Pekhiv AP et al.; The conjugation between the typed strains of E . coli belonging to various serological groups and conjugation between typed and untyped E . coli strains were studied . Genetic determinant controlling the synthesis of the O100 antigen proved to be closely linked with histidine locus . Among recombinants obtained in crossing the typed E . coli strains there were such belonging to the serological type different from the serological types of donor and recipient cells.

Nucleic Acids Res, 1977 Jul, 4(7), 2283 - 92
A rapid cytosine-specific modification of E . coli tRNA Leu 1 by semicarbazide-bisulfite, a probe for polynucleotide conformations; Negishi K et al.; Cytosine residues in 32P-labeled E . coli tRNA Leu 1 were modified by treatment of the tRNA with the semicarbazide-bisulfite reagents {Hayatsu, H . (1976) Biochemistry 15, 2677-2682} . Analysis of the modification sites showed that only four cytidine residues, i.e . C35, C53, C85 and C86, reacted . They were identical with the cytidines of this tRNA accessible to methoxyamine {Chang, S . E . and Ish-Horowicz, D . (1974) J . Mol . Biol . 84, 375-388} and the accessibility was consistent with the conformational features recognized for tRNA in general . The rapidity and the simple nature of this modification demonstrate that the semicarbazide-bisulfite reaction is a useful tool in studying conformations of polynucleotides.

Mol Biol (Mosk), 1977 Jul-Aug, 11(4), 843 - 53
{Mathematical model of tryptophan synthesis and excretion into the environment by E . coli cells}; Drozdov-Tikhomirov LN et al.; A quantitative kinetic model is suggested for the auto-regulated tryptophan synthesis by E . coli trp-operon system and for tryptophan excretion from the cell mediated by transport systems . Applications of the model for the calculation of several parameters characterizing tryptophan metabolism are considered . In order to explain experimental data it is suggested that a system of tryptophane excretion from the cell exists which is induced by high tryptophan concentrations . The rate of tryptophan excretion was studied as a function of various genetic effects (derepression or reduction of retroinhibition) as well as of changes in intracellular concentrations of substrates of tryptophan synthesis (chorismic acid and serine) . Possible ways of making the cell to excrete markedly higher quantities of tryptophan without changing the genotype are discussed.

Biull Eksp Biol Med, 1977 Jul, 84(7), 104 - 6
{Test-strains of E . coli for detection of chemical mutagens}; Pekhov AP et al.; Two temperature-sensitive mutants--AP 16 and AP 18 were isolated after the treatment of E . coli AB2500 strain with two mutagens (acridine orange and 5-bromuracil) . The mutants obtained proved to be sensitive and formed revertants when treated with the following agents: N-methyl-N'-nitro-N-nitrosoguanidine, hydroxylamine, nitrous acid, sodium metabisulfite, methylmethansulfonate, and proflavine . Introduction into the mentioned strains of additional mutation causing elevation of their sensitivity to crystal violet increased somewhat their capacity to form revertants under the effect of proflavine and methylmethansulfonate.

Cell, 1977 Jul, 11(3), 551 - 9
Synthesis and assembly of the membrane proteins in E . coli; Ito K et al.; Kinetics of integration of membrane proteins were studied in E . coli to discover how membrane proteins find their final location in the functional membrane . The experiments make use of a simple and convenient method developed for isolating inner and outer membranes from a number of small-scale cultures with high recovery . Among the proteins that constitute the cell surface structures, inner membrane proteins are integrated most rapidly after synthesis, whereas outer membrane proteins delay somewhat, and periplasmic proteins delay further in reaching their destinations . Protein I, a major outer membrane protein with molecular weight of about 37,000 daltons, exhibits significantly slower rates of integration than other outer membrane proteins . The decreased fluidity of membrane lipids by temperature shiftdown of an unsaturated fatty acid auxotroph grown on elaidate results in abnormally slow assembly of the outer membrane proteins and also in an anomalous assembly of the inner membrane proteins, suggesting that the fluid state of the lipids is required for normal operation of these processes . The possible relevance of these findings to the mechanism of membrane formation is discussed.

Gene, 1977 Jul, 1(5-6), 347 - 56
E . coli phosphofructokinase synthesized in vitro from a ColE1 hybrid plasmid; Thomson JA; A hybrid plasmid, pLC 16-4, from the ColE1-DNA (E . coli) bank of Clarke and Carbon (1976) carrying pfkA was used to program an in vitro protein synthesis system from E . coli . Phosphofructokinase was the main product, as determined by enzyme assay, immunoprecipitation and gel electrophoresis . The enzyme was synthesized in vitro without added cAMP at a rate (enzyme/genome/h) ca . 30% the in vivo value, a higher efficiency than usually found in cell free systems . The plasmic molecular weight is ca . 16.10(6) daltons.

Mol Gen Genet, 1977 Jun 24, 153(3), 337 - 41
Linkage of 5S RNA and 16S+23S RNA genes on the E . coli chromosome; Vola C et al.; Episomes carrying limited regions of the chromosome where 5S RNA genes have previously been located are described . The DNA purified from each of these episomes contains one gene per molecule for each of the three ribosomal RNA species as shown by hybridization experiments.

Vet Med (Praha), 1977 Jun, 22(6), 333 - 42
{Incidence and mobility of R plasmids, Col plasmids and Hly plasmids in E . coli isolated from healthy calves and calves with diarrhea}; Sokol A et al.; Within the set of 200 strains of E . coli isolated from healthy calves and 60 strains of E . coli isolated from calves suffering from diarrhoea we compared the incidence and transfer of determinants of antibioticoresistance, colicinogenesis and hemolytical activity . A significant difference in the incidence and independent mobility of the agents under examination in favour of E . coli from calves suffering from diarrhoea was determined in the case of resistance to chloramphenicol . The increased incidence and independent mobility of the chloramphenicol element in the antibioticoresistent strains of E . coli isolated from calves suffering from diarrhoea can be explained by the three to five-day therapy with a chloramphenicol product.

J Microw Power, 1977 Jun, 12(2), 141 - 4
Effects of 2.6-4.0 GHz microwave radiation on E-coli B; Corelli JC et al.; The effects of 2.6-4.0 GHz microwave radiation on living E . coli B bacteria were studied using measurement of the colony forming ability (CFA) of the cells and alterations in the molecular structure determined by comparing the infrared spectrum of irradiated and unirradiated cell cultures . At absorbed power levels of 20 mW in 1 ml of cellular suspensions (i.e., a specific absorption rate of 20 W/kg) for 10-12 hour exposures, no effects were observed on either the molecular structure or the CFA for this particular strain of E . coli.

Cell, 1977 Jun, 11(2), 247 - 62
Spacer transfer RNAs in ribosomal RNA transcripts of E . coli: processing of 30S ribosomal RNA in vitro; Lund E et al.; At least three different transfer RNAs are produced by in vitro processing of 30S ribosomal RNA which accumulates in RNAase III- strains of E . coli . Two of these tRNAs, tRNAGlu2 and tRNAIle1, have previously been shown to be "spacer tRNAs"--that is, genes for their synthesis are located in rRNA transcription units between the cistrons for 16S and 23S rRNAs (Lund et al., 1976) . The third tRNA whose sequences are contained in 30S rRNA is tRNAAla1B . In addition to the tRNAs, 5S rRNA and several other 4S fragments are produced . Some of these 4S fragments may represent additional spacer tRNAs . One fragment, about 70 nucleotides long, arises from the 5' end of the 17S precursor of 16S rRNA . Four or five other tRNAs are hydrogen-bonded to 30S rRNA as we prepare it; one or more of these tRNAs may also be a spacer tRNA . The enzymes that process tRNAs out of 30S rRNA are associated with ribosomes, but can be removed from them by washing in 0.2 M NH4Cl; the enzymes required for 5S rRNA processing remain bound to the 0.2 M NH4Cl-washed ribosomes . Treatment of 30S rRNA with purified RNAase III produces 6-8S fragments which contain the sequences of tRNAGlu2, tRNAAla1B and 5S rRNA.

Biokhimiia, 1977 Jun, 42(6), 1117 - 22
{T2 DNA, modified by 2,2,6,6-tetramethyl-4-bromoacetooxypiperidine-i-oxyl as a template for RNA polymerase from E . coli B}; Kamzolova SG et al.; T2-DNA was modified by 2,2,6,6-tetramethyl-4-bromoacetooxypiperidine-1-oxyl (I) at different NaCl concentrations (10(-1) M NaCl--10(-4) M NaCl) . Modified DNA were investigated as templates for the RNA-polymerase from E . coli B . It was shown that T2-DNA modified I in 0,1 M NaCl completely preserves the native secondary structure, has a low degree modification (1 molecule I per 1000-2000 nucleotide pairs), but is a noneffective template for the RNA-polymerase from E . coli B (20%-40% as compared with unmodified T2-DNA) . Under these conditions the modification occurs probably at the "weakest" (readily melting) sites of DNA . The role of these "weak" sites on DNA as promotors is discussed . The modification of T2-DNA by reagnet I has a stronger inhibitory effect on the total RNA synthesis than on the RNA-synthesis stable to rifampicin . Possible existence of two kinds of "early" promotors on T2-DNA is assumed.

Antibiotiki, 1977 Jun, 22(6), 536 - 9
{Electron microscopic study of the combined action of ampicillin and cephalexin on E . coli}; Chavdarova V et al.; The data of electron microscopy study of morphological variation of E . coli, strain 423 in the logarithmic phase after exposure to ampicillin (2 gamma/ml) and cephalexin (4 gamma/ml) are presented . Pronounced ultrastructural changes not only in the cell wall but also in the cytoplasm were found . After exposure to ampicillin alone changes of the same type were observed . However, after exposure to the combination of the 2 antibiotics these changes were more pronounced and observed in the predominating part of the cells . Examination of ultrathin slices of the strain treated with cephalexin revealed no ultrastructural changes . The morphological changes in the cells of E . coli, strain 423 after its treatment with ampicillin and cephalexin combination were due mainly to ampicillin effect, while cephalexin increased the level of the changes.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Jun, 31(6), 577 - 87
Some mechanisms involved in the radiosensitization of E . coli B/r by paracetamol; Shenoy MA et al.; Paracetamol, a widely-used analgestic and antipyretic drug, sensitized E . coli B/r to 60Co gamma-rays under hypoxic conditions . Part of the sensitizing effect has been shown to be due to an electron adduct of the drug . Paracetamol inhibited both post-irradiation DNA and protein syntheses . The targets involved in the inhibition of post-irradiation DNA synthesis have been shown to be different in the presence of the sensitizer . Increased DNA degradation after irradiation was also observed when E . coli B/r were irradiated in the presence of the drug . The presence of paracetamol during hypoxic irradiation of E . coli B/r resulted in the enhancement of DNA single-strand scissions with no apparent effect on their rejoining.

Can J Microbiol, 1977 Jun, 23(6), 779 - 89
Preferential inhibition of phosphatidyl ethanolamine synthesis in E . coli by alcohols; Ingram LO; Growth of E . coli in the presence of alcohols of chain lengths 1 through 8 results in an increase in the relative abundance of phosphatidyl glycerol . This results primarily from the preferential inhibition of phosphatidyl ethanolamine synthesis . This inhibition appears to be unrelated to membrane fluidity or to changes in fatty acid composition caused by alcohols . Alcohol-induced changes in total fatty acid composition are reflected in all phospholipid classes . Phosphatidyl serine synthetase is proposed as the most likely site for the effects of alcohols on phospholipid synthesis.

Nucleic Acids Res, 1977 Jun, 4(6), 1793 - 802
In vitro transcription of herpes simplex virus ANG DNA by E-coli RNA polymerase; Strauss GP et al.; HSV-1 ANG DNA and a defective genome of the same virus were transcribed with E . coli RNA polymerase under various salt conditions . The extent of transcription was assayed by hybridizing the cRNA to the Hind III, Hpa I and Hind II restriction fragments of the DNA templates using the blot technique of E . Southern . The transcripts proved to contain sequences homologous to all DNA fragments . A similar ratio of hybridized cRNA and the amount of fragment DNA was observed in all cases . The results suggest that both, the wt and the defective HSV ANG genome were completely transcribed.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Jun, 31(6), 519 - 27
On the protection of E . coli against radiation lethality by ascorbate combined with tetracycline; Djalali-Behzad G et al.; The radioprotective action in E . coli ATCC 9637 of ascorbate added to media containing the weak sensitizer, tetracycline (effect described by Pittillo and Lucas (1967)), was found to be dependent on the presence of metal catalysts of the autoxidation of ascorbate . Thus, the protective action of ascorbate + tetracycline as well as the rate of autoxidation of ascorbate in this mixture were enhanced by 0.1 micron Cu, and these effects were counteracted by pyrophosphate probably through chelation of iron that contaminates phosphate . A suppression of metabolism is apparently involved in the combined action as judged by the decrease of incorporation of labelled uridine.

Biull Eksp Biol Med, 1977 Jun, 83(6), 744 - 6
{Functioning of the lactose operon of E . coli K-12 under the influence of non-specific regulators}; Boichenko MN; A possible role played by cAMP in the stimulating action of ACTH and hydrocortisone on lactose E . coli K-12 operon was studied . It was shown that ACTH caused no effect in the E . coli WZ-78/F'lac (cya855) and E . coli CA8001 (L1) strains with destroyed positive cAMP control system of the lactose operon function, at the same time producing a stimulating effect on the lactose operon in the strains of wild type, i.e . E coli 200PS/F'lac and E . coli 3000 . Hydrocortisone stimulated the lactose operon function both in E . coli 3000 and in the mutant E . coli CA8001 (L1) . It was supposed that the accelerating effect of ACTH on the lactose operon was mediated through cAMP; as to hydrocortisone--it stimulated the lactose operon function independently of cAMP.

Carbohydr Res, 1977 Jun, 56(1), 153 - 64
Binding of alkyl 1-thio-beta-D-galactopyranosides to beta-D-galactosidase from E . coli; De Bruyne CK et al.; The binding of a series of alkyl 1-thio-beta-D-galactopyranosides to beta-D-galactosidase from E . coli has been investigated . The inhibition constants were compared to the partition coefficients for the transfer of these substrate-analogues from water to 1-octanol . The relationships between the observed binding-constants and the partition coefficients indicate that part of the aglycon group binds to a hydrophobic area that is limited in relation to the length of hydrocarbon chain that can be accomodated . Outside this area, the hydrocarbon chain is only partially desolvated . The main driving-force for binding of the aglycon group is the increase in entropy resulting from the return of water molecules from the more-organized layer around the solute molecule to the bulk-water phase.

Mol Gen Genet, 1977 May 20, 153(1), 87 - 97
A conditional antimutator in E . coli; Geiger JR et al.; A pleiotropic mutation in the purB gene of E . coli is described which lowers the spontaneous mutation frequency of other genes . The antimutator effect is very large for some genetic loci, but is absent at other sites . Both forward and reverse mutations are affected . This mutation in purB is temperature sensitive for both adenine auxotrophy and the antimutator action . Adenine, or adenosine, or low temperature growth abolish the antimutator effect . The mutagenicity of base analogs and nitrosoguanidine at several loci was found to be reduced by this purB mutation . The antimutator effect is recessive in strains merodiploid for the purB region . The frequency of reversion of mutation on F' episomes is affected by the chromosomal antimutator, which therefore acts in trans . Xray and UV sensitivity are normal in this mutant, which is the first antimutator characterized in E . coli.

Mol Biol (Mosk), 1977 May-Jun, 11(3), 671 - 6
{Fragment reaction catalyzed by E . coli ribosomes}; Kotusov VV et al.; It has been shown that 50S subunits of E . coli MRE-600 ribosomes catalyze the reaction of N-(formyl)-methionyl ester of adenosine 5'-phosphate acting as peptide donor, with Phe-tRNA or CACCA-Phe serving as a peptide acceptor . The reaction is stimulated by cytidine 5'phosphate and inhibited by lincomycin, puromycin and chloramphenicol . The obtained results show that the structure of the donor site of peptidyltransferase is completely assembled on the 50S subunit and 30S subunit is not required for its formation.

Mol Biol (Mosk), 1977 May-Jun, 11(3), 545 - 54
{Compact structure of the small E . coli ribosomal subunit and its RNA studied by fluorescence spectroscopy and sedimentation analysis}; Potapov AP et al.; Analysis of the temperature dependence of fluorescence polarization of ethidium bromide adsorbed on the double helical fragments of 16S RNA's hairpin loops was used to characterize the intramolecular flexibility of RNA in the free state and within 30S subunit . We show that the local mobility of RNA segments is strongly limited by the tertiary structure of 16S RNA and ribosomal proteins reinforce these limitations . It was suggested that the mechanism of the temperature dependent RI particle activation involved the temporary increase of the local mobility of RNA segments in RNP which favored the formation of the new intraribosomal contacts . A comparison of sw 20 dependences of RNA and 30S subunit on Mg+ and K+ concentrations leads to the proposal that RNA in the small subunit in the physiological conditions has the stressed conformation . This conformation is maintained by the Mg2+-dependent RNA-RNA interactions induced by ribosomal proteins and specific only for the subunit.

Poult Sci, 1977 May, 56(3), 957 - 63
Effect of vitamin E and A on humoral immunity and phagocytosis in E . coli infected chicken; Tengerdy RP et al.; Dietary supplementation of either vitamin E (300 mg./kg . diet) or vitamin A (60,000 I.U./kg . diet) significantly reduced E . coli caused mortality, but the combination of the two vitamins did not . Protection was attributed to increased antibody production and increased phagocytosis, although neither factor alone gave a significant correlation with mortality . Vitamin E level significantly increased especially in the spleen of supplemented chicks, but vitamin A suppressed this increase, partially explaining the lack of protection in vitamin E and A supplemented chicks.

Zh Mikrobiol Epidemiol Immunobiol, 1977 May, (5), 42 - 6
{Clinico-laboratory substantiation of possible use of the indirect hemagglutination test for the interpretation of diagnosis of enteropathogenic E . coli carrier state}; Speranskii NP; The diagnostic value of the indirect hemagglutination (IHA) test in deciphering the diagnosis of enteropathogenic E . coli carrier state was found in this work; this was done by comparing the specific antibody level in carriers and patients suffering from coli-infection and also by establishing the correlation between the results of the IHA test and the clinical and laboratory examination of carriers.

Biokhimiia, 1977 May, 42(5), 784 - 7
{On the role of N7 atoms of guanosine in tRNA-Phe (E . coli) in interaction with ribosomes}; Vlasov VV et al.; The influence of alkylation of phe-tRNAPhe (E . coli) with 2',3'-O-{4-(N-2-chloroethyl-N-methylamino)-benzylidene}-uridine - 5' - methylphosphate on its ability to participate in non-enzymatic complex formation with ribosomes and poly-U was investigated . Phe-tRNAsPhe, containing alkylated guanosines at different positions, including anticodone, are active in binding with ribosomes . It is concluded, that N7 nitrogens of guanosine of the tRHAPhe are not elements, significant for the interaction with ribosomes.

Chem Biol Interact, 1977 May, 17(2), 121 - 7
Effect of some drugs on excision repair in E . coli cells; Masek F; The intercalating dye ethidium bromide (EB), inhibits excision of pyrimidine dimers from UV-irradiated excision-proficient Escherichia coli B/r hcr+ cells . Inhibition is total at a 2.5 - 10(-4) M concentration 120 min after irradiation with a dose of 750 erg/mm2 . The viability of irradiated cells diminishes in proportion to the EB concentration . Under wholly analogous conditions of cultivation and irradiation no inhibitory effect of KCN and caffeine (CFF) and only a slight effect of chloramphenicol (CAP) on dimer excision has been observed . The viability of cells is affected by these compounds but it does not appear to depend on the quantity of excised photoproducts . A change in the secondary structure of DNA induced by intercalation of EB appears to be the reason for the depression of excision of UV photoproducts.

Biull Eksp Biol Med, 1977 May, 83(5), 597 - 9
{Interaction of the isolated DNA of lambda phage with spheroplasts of E . coli treated with sturine}; Moiseeva TF et al.; The method of centrifugation in sucrose density gradient (30-55%) of the spheroplast membrane preparations treated and untreated with sturine and infected with phage lambda DNA demonstrated that sturine, treatment increased the phage lambda DNA absorption three-fold . About 50% of the lambda DNA molecules adsorbed by spheroplasts are bound with the cytoplasmic membrane of spheroplasts treated with sturine; 50% of the lambda DNA molecules are bound with the cell wall membrane on the sturine-untreated spheroplasts . The data obtained allow to conclude that the stimulating effect of sturine in E . coli spheroplasts transfection by lambda DNA is connected with redistribution of phage DNA absorbed on spheroplasts from the cell wall to the cytoplasmic membrane facilitating the penetration of DNA and its fastening on the membrane.

Antibiotiki, 1977 May, 22(5), 429 - 32
{Action of various surface-active substances on the genetic transmission of R-plasmids in E . coli}; Glatman LI et al.; The effect of 4 groups of surface active-substances (SAS) on conjugation and transduction transfer of plasmid RIdrd from the donor of E . coli J 5-3 to the recipient of E . coli C600 was studied . It was shown that the anionic SAS (8 compounds) had the highest inhibitory effect . They completely inhibited both the conjugation and the transduction transfer of R-plasmids . The amphoteric SAS, i . e . tego-51 and ampholan had the same effect only on the transduction R-transfer . The conjugation R-transfer was inhibited by the above compounds to a significant extent but not completely, i . e . by 70.8 and 361.9 times respectively . The effect of the non-ionogenic preparations, i . e . sintanol DT-7 was even less (the inhibition coefficients of 54.8 and 22.8 on conjuction and transduction respectively) . The cationic SAS, i . e . catamine AB and HIPC-200 had no effect on the genetic R-transfer . It was shown that the anionic SAS had a phagocytic effect on phage Plks . It is of interest to note that the anionic SAS, i . e . sintanol NP-3 effectively suppressed the conjugation transfer even in a concentration of 100 gamma/ml which was 1000 times lower than the subbacteriostatic one . The effectiveness of the anionic SAS did not depend on the length of the dydrocarbon chain and was the same in separate homologues and their mixtures . The high inhibitory activity of most of the SAS and especially the anionic ones with respect to both the conjugation and the transduction R-transfer was of interest.

Exp Hematol, 1977 May, 5(3), 166 - 70
Granulocyte transfusions in recovery of neutropenic rats from induced E . coli toxicemia; Popovic V et al.; Rats made transiently neutropenic by intra-arterial administration of vinblastine (3 mg/kg) and infected with E . coli (6.02+/-0.45 X 10(8), per animal) have a mortality rate of 90% within 48 h post infection . Multiple transfusions of large numbers of granulocytes (harvested from Deca-Durabolin treated donor rats) protected the neutropenic animals from sepsis . Out of a group of 11 rats, 10 recovered completely after repeated granulocyte transfusions.

Infect Immun, 1977 Apr, 16(1), 344 - 52
Colonization of porcine intestine by enterotoxigenic Escherichia coli: selection of piliated forms in vivo, adhesion of piliated forms to epithelial cells in vitro, and incidence of a pilus antigen among porcine enteropathogenic E . coli; Nagy B et al.; In contrast to K88-positive porcine enterotoxigenic Escherichia coli (ETEC), K88-negative porcine ETEC strains did not adhere to isolated intestinal epithelial cells in vitro . However, they did adhere to intestinal epithelium in vivo . Growth of one such ETEC (strain 987) in pig small intestine consistently yielded a greater percentage of piliated cells than did growth in vitro . This increase was demonstrable by electron microscopy, by change in colonial morphology, and by agglutination in specific antisera against the pili of strain 987 . In contrast to the stored stock culture (which contained very few piliated cells), richly piliated forms of strain 987 did adhere to isolated intestinal epithelial cells in vitro . A series of porcine E . coli strains was tested for agglutinability in antiserum against the pili of strain 987, and several K88-negative ETEC strains were agglutinated . These data are consistent with the hypothesis that pili facilitate intestinal adhesion and colonization by K88-negative ETEC strains.

Zentralbl Bakteriol {Orig A}, 1977 Apr, 237(4), 483 - 93
A contemporary review of incidence and detection of enterotoxigenic E . coli strains in human diarrheal diseases; Miller I et al.; Methodical possibilities for detection of enterotoxic strains of E . coli and the frequency of appearence of these strains in infants and adults suffering from diarrheal diseases are reviewed . Our own study, using the ligated rabbit intestinal loop, revealed 6.8% incidence of enterotoxin producing strains among the classical enteropathogenic serotypes of E . coli, isolated from stools of infants with mild diarrhoea . The model of mice intestinal loop was not found to be suitable for detection of enterotoxin of E . coli strains . The most sensitive model seems to be the intestine of precolostral piglet; however this model is not suitable for routine tests.

Nucleic Acids Res, 1977 Apr, 4(4), 877 - 82
Effect of salt on the transcription of T7 DNA by RNA polymerase from T4 phage-infected E.coli; Stevens A; Transcription of T7 DNA by T4 core enzyme with host sigma is more sensitive to KCI than that by host core enzyme with host sigma . When salt is added after initiation of RNA chains has occurred, it is not inhibitory . Salt affects the binding of T4 enzyme to T7 DNA to the same degree as the binding of host enzyme . Active preinitiation complex formation is inhibited more by salt with the T4 enzyme and the inhibition is temperature-dependent.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Apr, 31(4), 303 - 19
{Formation of covalent linkages between the nucleic acid and protein constituents of E . coli MRE 600 ribosomes during gamma irradiation}; Ekert B et al.; Gamma-irrdiation of E . coli MRE 600 ribosomes in aqueous suspensions leads to covalent linkages between the RNA and some ribosomal proteins . The presence of oxygen during the irradiation strongly inhibits this phenomenon . It appears clearly that only a few proteins are able to participate in these cross-linking reactions, which occur simultaneously in the two sub-units . The radiochemical yield was determined at several concentrations and was relatively low.

Can J Biochem, 1977 Apr, 55(4), 346 - 58
An effect of enzyme and ligand concentration on the state of aggregation of aspartate transcarbamylase of E . coli: I . The binding of CTP and ATP to the enzyme; Cook RA et al.; Detailed binding studies of the inhibitor, cytidine triphosphate (CTP), to native Escherichia coli aspartate transcarbamylase (EC 2.1.3.2) reveal significant changes in subunit interaction when enzyme concentration is altered . In contrast, similar binding studies of the activator, adenosine triphosphate (ATP), do not reveal such changes, but do indicate more complex subunit interactions than previously reported . Equilibrium dialysis studies of 4 degrees C are consistent with six binding sites for CTP and ATP per enzyme molecule of molecular weight 310 000, at all enzyme concentrations . CTP binding studies reveal a progressive change from apparent positive to negative cooperativity as the enzyme concentration is decreased . ATP binding studies reveal complex subunit interactions involving a mixture of apparent negative and positive cooperativity . Sucrose gradient studies indicate the presence of at least three enzymatically active polymeric forms of the enzyme . The preliminary sedimentation studies indicate possible ligand and enzyme concentration perturbations of a preexisting association equilibrium in the aspartate transcarbamylase system . The binding data are therefore interpreted in terms of an association model.

Mol Gen Genet, 1977 Mar 28, 152(1), 1 - 6
In vitro transcription of three different ribosomal RNA cistrons of E . coli; heterogeneity of control regions; Oostra BA et al.; Ribosomal RNA synthesis from three different rRNA cistrons of E . coli, located on different phage DNAs was compared and found to have the same characteristics as regards chain length, salt and temperature dependence and the effect of ppGpp . However, some clear and reproducible quantitative differences between rRNA synthesis from the different templates both in presence and absence of ppGGpp were found . Rifampicin and heparin experiments showed that these differences were located at the initiation sites . We propose that heterogeneity exists in the RNA polymerase binding regions of the rRNA prmoters in E . coli.

Mol Gen Genet, 1977 Mar 16, 151(3), 313 - 8
Growth and reactivation of single stranded DNA phage phiX174 in E . coli undergoing "thymineless death"; Thakur AR et al.; The thymine requirement of the E . coli strain HF 4704 (uvr A-, rec A+) is thermosensitive i.e . these cells require for their growth 2 microng thymine per ml at 37 degrees C but not at 30 degrees C . Such cells when starved for thymine for 3 h at 37 degrees C are capable of sustaining growth of single stranded DNA phage phiX174 without any diminution of burst size under nonpermissive conditions . Thymine starved HF 4704 cells also reactivate UV-irradiated phiX174 by about 3fold . To test if the thymine necessary for phage growth under "thymineless" conditions was supplied by host DNA degradation products, the transfer of 32P label from the host DNA to mature progeny phages was measured by means of sucrose density gradient analysis . It was found that only about 0.7% of 32P of the host DNA was transferred to the progeny phages growing in normal cells whereas the corresponding value was 7.8% in the case of thymine starved cells.

Mol Gen Genet, 1977 Mar 16, 151(3), 305 - 12
In vitro transcription of the ribosomal RNA genes of E . coli DNA; Sumegi J et al.; Bacterial ribosomal RNA synthesis was studied in an in vitro system in which the presence of heparin prevented reinitiation of transcription . The number of heparin-resistant binary complexes of RNA-polymerase and E . coli DNA depended strongly on the quality of the template . High-molecular weight DNA was a much superior template than DNA prepared by conventional techniques . Using this high-molecular weight DNA as template the amount of ribosomal RNA synthetized in one round of transcription was found to be 4-5 fold higher than the amount of rDNA present . Controls have shown that the transcription probably started at the proper initiation sites and no significant read-through form distant promoters contributed to this effect . If the binary polymerase-DNA complexes were dissociated in the presence of 0.5 M KC1 prior to transcription all RNA synthesis was strongly reduced but the proportion of rRNA increased in the transcript . However, in this case the amount of rRNA did not exceed the amount of rDNA . We propose that the promoters of the rRNA genes are complex structures, able to store 4-5 molecules of RNA polymerase and of these several polymerase only one is bound in an extremely salt-resistant form.

Mol Gen Genet, 1977 Mar 16, 151(3), 295 - 304
Suppression of polarity of insertion mutations within the gal operon of E . coli; Besemer J et al.; Phenotypic revertants of galOP::IS1 and galOP::IS2 mutations have been isolated after mutagenesis with nitrosoguanidine, they are probably caused by mutations in gene suA . The polarity suppressor mutations described in this study and a known mutation in gene suA isolated by D . Morse (Morse and Guertin, 1972) suppress polarity caused by IS1 more effectively than that caused by IS2 or IS4 . Furthermore, suppressibility is influenced by the site and orientation of IS integration . The synthesis of the three enzymes in galOP::IS suA double mutants is constitutive and the ratio of the three enzymes is altered in comparison to the wild type . The reasons for constitutive synthesis of the galactose enzymes and for the altered ratio of enzyme synthesis are discussed.

Experientia, 1977 Mar 15, 33(3), 384 - 6
Conversion of psoralen DNA monoadducts in E . coli to interstrand DNA cross links by near UV light (320-360 nm): inability of angelicin to form cross links, in vivo; Ashwood-Smith MJ et al.; Both angelicin and psoralen monoadducts formed in vivo in E . coli by near UV light produce lethal and mutagenic effects . However psoralen monoadducts are converted to cross links by higher doses of UV; angelicin monoadducts are not . The relevance of these results to psoralen photosensitization is discussed.

Pflugers Arch, 1977 Mar 11, 368(1-2), 125 - 8
Fever in rats after intravenous E . coli endotoxin administration; Splawinski JA et al.; In conscious unrestrained rats, at an ambient temperature of 22 degrees C, oesophageal temperature was measured and temperature effect of single and repeated intravenous injection of E . coli endotoxin was examined . The first injection of endotoxin in a dose of 10.0 mug/rat did not change the rat body temperature . The second injection of this dose in the same animals repeated after 48 h produced fever . With following injections the fevers observed were less pronounced . The absence of fever after a single injection of endotoxin was accompanied by the rapid loss of pyretic activity of the rat plasma samples (bioassayed in rabbits) . When fever was observed (48 h interval between endotoxin injections) the pyretic activity of the rat plasma remained unchanged for 90 min following endotoxin injection . It was concluded that after a single injection endotoxin is rapidly detoxified in the rat circulation while this process does not take place after the second endotoxin injection (48 h interval) . The process of endotoxin detoxification can be depressed by the pretreatment with nitrogen mustard . Analysis of changes of skin temperature following endotoxin injections and the influence of aspirin on endotoxin-induced fever suggest that the fever observed was of central origin.

Pflugers Arch, 1977 Mar 11, 368(1-2), 117 - 23
Fever produced in the rat by intracerebral E . coli endotoxin; Splawinski JA et al.; E . coli endotoxin introduced into the brain ventricles or into various brain areas raises the body temperature of conscious rats . Endotoxin-sensitive sites were found within the anterior hypothalamus and the lower brainstem . The increase in temperature (delta T) after microinjection of endotoxin into the anterior hypothalamic nucleus was dose-dependent . Endotoxin injected into the ventricles produced monophasic hyperthermia, but microinjections into the anterior hypothalamus produced monophasic or biphasic types of hyperthermia . The second and third microinjections of endotoxin into the anterior hypothalamic nucleus subsequently caused higher responses in delta T, but not in the rate of temperature change . The effects of the fourth and furter microinjections were the same as those of the third, and no tolerance developed for 24 days . The observations of behaviour, vegetative reactions, skin temperature, and carbon dioxide production indicated that the rise in the rat body temperature induced by endotoxin represents fever and that the heat is gained, at an ambient temperature of 22 degrees C, mainly through skin vessel vasoconstriction . Aspirin abolished and reversed fever induced by endotoxin, while hydrocortisone was without effect.

Mol Gen Genet, 1977 Mar 7, 151(2), 161 - 8
Studies on the bipolar argECBH operon of E . coli: characterization of restriction endonuclease fragments obtained from gammadargECBH transducing phages and a ColE1 argECBH plasmid; Crabeel M et al.; The isolation of a new type of gamma transducing phage carrying the bipolar argECBH operon of E . coli K12 is described . The argECBH segment is inserted in the phage in a direction which is opposite from that of previously isolated argECBH-carrying phages . A colE1 argECBH plasmid has been constructed . DNA fragments resulting from digestion of these genetic elements with Eco RI and Hind III restriction enzymes have been characterized by agarose gel electrophoresis and electron microscopy, including hetero-duplex analysis . Two fragments are of special significance for studies on the control of arginine synthesis, one of length 9.8 kilobases carrying the whole argECBH region, the other of length 2 kilobases carrying most or all of the control region between argE and argC.

Cell, 1977 Mar, 10(3), 521 - 36
Protein expression in E . coli minicells by recombinant plasmids; Meagher RB et al.; The polypeptides synthesized in E . coli minicells from recombinant plasmids containing DNA fragments from cauliflower mosaic virus, Drosophila melanogaster, and mouse mitochondria were examined . Molecularly cloned fragments of cauliflower mosaic virus DNA directed the synthesis of high levels of three polypeptides, which were synthesized entirely from within the cloned virus DNA fragments independent of their insertion into the plasmid vehicles . Several fragments of D . melanogaster DNA were capable of initiating polypeptide synthesis; however, termination of these polypeptides was dependent upon the insertion into the plasmid vehicle . The majority of D . melanogaster DNA fragments examined did not direct the detectable synthesis of any polypeptides . Insertion of DNA into the Eco RI site of ColE1 and pSC101 plasmids resulted in the altered expression of plasmid-encoded polypeptides . In the case of ColE1, this site of insertion lies within the colicin E1 structural gene, and insertion of foreign DNA into the site results in the synthesis of an inactive truncated colicin E1 molecule . It is probable that the Eco RI site in pSC101 lies within the structural gene for a polypeptide involved in tetracycline resistance, and insertion of DNA into this site may also result in the synthesis of a truncated or elongated polypeptide.

Mol Biol (Mosk), 1977 Mar-Apr, 11(2), 403 - 9
{Methylation of E . coli RNA polymerase with dimethylsulfate}; Chenchik AA et al.; DNA dependent RNA polymerase from E . coli was methylated with dimethylsulfate . After the methylation the enzymatic activity was lost . Addition of two methyl groups per enzyme monomer completely inactivated enzyme with respect to RNA synthesis but couldn't prevent enzyme binding to DNA . Methylated enzyme was able to form tight complexes with DNA and to compete with the native enzyme for the formation of rifampicin resistant complex with DNA . The ratio of the binding constants of the native and methylated enzymes to DNA was determined to be equal to 3 . Methylated enzyme was not able to form the first phosphodiester bound as revealed from pyrophosphate exchange reaction studies.

Mol Biol (Mosk), 1977 Mar-Apr, 11(2), 394 - 402
{Substrate specificity of E . coli glutamate decarboxylase}; Sukhareva BS et al.; Interaction of highly purified E . coli glutamate decarboxylase with a number substrate analogs was studied . Decarboxylation of the following amino acids was demonstrated: gamma-methylene glutamate, threo-beta-hydroxyglutamate, allo-gamma-hydroxyglutamate, threo-beta-methylglutamate, homocysteate, aminoadipate and cysteinesulfinate . The Km and either Ki or I50 values were determined for these compounds . The final products of the interaction of glutamate decarboxylase with these analogs have the same absorption spectra and capacity for reactivation by pyridoxal-P, as has the pyridoxamine-P form of the enzyme . Thus, decarboxylation of all the amino acids, mentioned above, was probably associated with the side reaction of transamination to coenzyme in the active center . Binding of aliphatic dicarboxylic acids or of valeric acid by glutamate decarboxylase leads to a slight shift of absorption spectra and of circular dichroism spectra from 420 to 423--425 nm . The following compounds fail to be bound and decarboxylated by the enzyme: gamma-aminobutyrate, D-glutamate, L-glutamine, 3,3-dimethylglutarate, methioninesulfone, methioninesulfoxide, norvaline, gamma-hydroxy-gamma-methylglutamate, erytro-beta-methylglutamate and erythro-beta-hydroxyglutamate.

Ital J Biochem, 1977 Mar-Apr, 26(2), 133 - 43
Ribosome maturation in E . coli; Silengo L et al.; In vivo and in vitro experiments have shown that processing of ribosomal RNA is a late event in ribosome biogenesis . The precursor form of RNA is probably necessary to speed up the assembly of ribomal proteins . Newly formed ribosomal particles which have already entered polyribosomes differ from mature ribosomes not only in their RNA content but also in their susceptibility to unfolding in low Mg concentration and to RNase attack . Final maturation of new ribosomes is probably dependent on their functioning in protein synthesis . Thus only those ribosomes which have proven to be functional may be converted into stable cellular structures.

Chem Phys Lipids, 1977 Mar, 18(2), 170 - 80
Interaction of membrane aminophospholipids of E . coli with fluorodinitrobenzene and trinitrobenzenesulfonate; Marinetti GV et al.; E . coli cells were reacted with TNBS in bicarbonate-NaCl buffer, pH 8.5 (buffer A) and in phosphate-NaCl buffer, pH 7.0 (buffer B) . In buffer A, DNP-GPE is the major product when FDNB is used . DNP-PE and DNP-LPE are formed in lesser amounts . Phospholipase A activity is high in buffer A . When TNBS is used, the labeling of the lipid components is less than with FDNB and more TNP-PE is formed relative to TNP-GPE . This data suggests that the phospholipases which are located primarily on the outer L-membrane of the cell wall act to a lesser extent on TNP-PE than on DNP-PE . E . coli cells were prelabeled with TNBS and FDNB in buffer A, washed and incubated in buffer A . The endogenous labeled DNP-PE gradually decreased with time with a concomitant increase in DNP-LPE and DNP-GPE due to phospholipase A activity . In contrast, the endogenous labeled TNP-PE also decreased with time as did the endogenous labeled TNP-LPE but a new orange lipid was produced . This lipid is believed to be a derivative of TNP-PE in which one of the nitro groups has been reduced to an amino group by nitroreductase . E . coli cells were prelabeled with TNBS and FDNB in buffer A, washed and incubated in buffer B . Under these conditions with both TNBS and FDNB there is an increase in TNP-PE and DNP-PE with a concomitant decrease in TNP-LPE, TNP-GPE, DNP-LPE and DNP-GPE . These results show that at neutral pH acylation occurs to regenerate TNP-PE and DNP-PE . E . coli cells were incubated with exogenous DNP-GPE or TNP-GPE in buffer A . The DNP-GPE and TNP-GPE were rapidly hydrolyzed by a phosphodiesterase to DNP-ethanolamine and TNP-ethanolamine . An orange derivative was formed which was provisionally identified as a derivative of DNP-ethanolamine or TNP-ethanolamine in which a nitro group has been reduced to an amino group by nitroreductase . The phospholipases and acylating enzymes present in the cell wall of E . coli are active on the dinitrophenyl and trinitrophenyl derivatives of PE and LPE and may act in concert to model and repair the plasma membrane.

Poult Sci, 1977 Mar, 56(2), 452 - 8
Comparison of therapeutic efficacy of doxycycline, chlortetracycline and lincomycin-spectinomycin on E . coli infection of young chickens; George BA et al.; Three replicate trials were conducted with broiler male chicks to test the therapeutic efficacy of doxycycline, chlortetracycline and lincomycin-spectinomycin in water against an artifically induced Escherichia coli infection . Mortality, lesion scores (heart, liver and air sac), and performance data were the criteria in evaluating therapeutic efficacy of these drugs . Results indicated the therapeutic efficacy of doxycycline was greater than chlortetracycline and lincomycin-spectinomycin.

Nucleic Acids Res, 1977 Mar, 4(3), 711 - 22
Introduction of antigenic determining 2,4-dinitrophenyl residues into 4-thiouridine, N3-(3-L-amino-3-carboxypropyl) uridine and tRNA-Phe from E . coli; Seela F et al.; The introduction of antigenic determining 2,4-dinitrophenyl residues into the rare ribonucleosides 4-thiouridine (1a), and N3-(3-L-amino-3-carboxypropyl) uridine (2) as well as into tRNA-Phe from E . coli has been investigated . Alkylation of 1a with omega-bromo-2,4-dinitroacetophenone (3b) gives S-(2,4-dinitrophenacyl)-4-thiouridine (5A) . Applying the reaction to the 5'-monophosphate of 1a, 5b is formed, but this product decomposes at pH 7 . However, acylation of 2 with 2,4-dinitrobenzoic acid N-hydroxysuccinimide ester (4b) leads to N3-{3-carboxy-3-L-(2,4-dinitrobenzamido)propyl}uridine (6) which is stable in aqueous solution . The latter reaction was used for the introduction of an antigenic determining 2,4-dinitrophenyl residue into tRNA-Phe from E . coli . The modified tRNA-Phe was isolated and by degradation of the molecule with RNase T2 and alkaline phosphatase the nucleoside derivative 6 was obtained and found to be identical with the synthetic product.

Mol Gen Genet, 1977 Feb 28, 151(1), 17 - 26
Characterization of an E . coli mutant with a thermolabile initiation factor IF3 activity; Springer M et al.; A thermosensitive E . coli mutant is described which has at least two defects in vitro: a thermolabile initiation factor IF3 activity and a modified L-phenylalanine: tRNAPhe ligase (EC 6.1.1.20) activity . These two defects cotransduce and are located near 38 min on the new E . coli map . Thermoresistant revertants showing in vitro reversion for one defect also revert in vitro for the other defect . The thermosensitive mutation is recessive to its wild type allele, and in vitro analysis of wild type/ mutant heterodiploids also show reversion for both defects.

Mol Gen Genet, 1977 Feb 15, 150(3), 293 - 9
A new technique for selection of sensitive and auxotrophic mutants of E . coli: isolation of a strain sensitive to an excess of one-carbon metabolites; Danchin A; An E . coli strain deleted in the region malasd is used for the selection of conditional or auxotrophic mutants . Thermosensitive and auxotrophic strains have thus been isolated on plates . After selection in liquid medium, a strain has been isolated which is sensitive to excess one-carbon metabolites . It carries two mutations, smg A1 (near metA and arg H), probably identical to relC, and smgB (between asn and ilv), probably part of the E . coli membrane ATPase.

Mol Gen Genet, 1977 Feb 15, 150(3), 257 - 64
Studies on ribosomal protein biosynthesis in an RNA polymerase temperature sensitive E . coli mutant; Pichon JL et al.; In E . coli strain XH56 the synthesis of all RNA species is blocked upon shifting the culture to the non-permissive temperature . The decay of specific messenger RNA species coding for individual ribosomal (r) proteins was followed by measuring the rate of r-protein synthesis by pulse labelling at various times after the shift . The half-lives of the average 30S r-protein and 50S r-protein mRNA species are identical (1.75 min) and shorter than those of the average messenger coding for total cell proteins (2.75 min) . Most individual r-protein messengers have a half-life in the same range (1.50-2.00) . Only a few r-protein messengers have significantly longer half-lives: S1 (2.80 min), S17 (3.29 min), L29 (2.30 min), L31 (2.30 min), L32 (2.33 min) and L16 (2.60 min) . The results indicate that the degradation of most individual r-protein mRNA species is not specifically controlled . After a few min at the non-permissive temperature, all protein synthesis is blocked . The restart of r-protein synthesis was followed after shifting the culture back to the permissive temperature . The recovery of cell growth is very slow . During this period preferential r-protein synthesis was observed . Moreover differential rates of bisynthesis of r-proteins was obtained, it may be indicative of specific regulatory process(es).

Infect Immun, 1977 Feb, 15(2), 614 - 20
Occurrence of K99 antigen on Escherichia coli isolated from pigs and colonization of pig ileum by K99+ enterotoxigenic E . coli from calves and pigs; Moon HW et al.; Several strains of enterotoxigenic Escherichia coli (ETEC) isolated from pigs were found to have an antigen (K99) previously reported only on strains of calf and lamb origin and which facilitates intestinal colonization in the latter two species . Several human ETEC were also tested for K99; however, none were positive . Each of four K99-positive ETEC strains of calf origin and one of pig origin produced K99 in pig ileum in vivo, adhered to villous epithelium in pig ileum, colonized pig ileum, and caused profuse diarrhea in newborn pigs . In contrast to the K99-positive strains above, four K99-negative ETEC from humans and chickens and one K99-positive ETEC from a calf either did not colonize pig ileum or did so inconsistently . When the K99-negative strains did colonize, they had little or no tendency to adhere to intestinal villi . These results are consistent with the hypothesis that K99 facilitates adhesion to and colonization of pig ileum by some ETEC.

Mutat Res, 1977 Feb, 42(2), 205 - 14
Induced reactivity of UV-damaged phage gamma in E . coli K12 host cells treated with aflatoxin B1 metabolites; Sarasin A et al.; The metabolites of aflatoxin B1, the most potent hepatocarcinogen so far known, promote in E . coli K12 cells the reactivation of phage lambda damaged by ultraviolet (UV) radiation . This reactivation process is error prone; 25% of the phage DNA lesions are repaired, but mutagenesis, scored as clear plaque formation, is increased as much as 10-fold . Such reactivation of UV-damaged phage lambda, which occurs in wild-type and in uvrA but not in recA bacteria, is inducible: phage reactivation is obtained even after a long delay following treatment of the host by the short-lived metabolites . This induced reactivation of UV-damaged phage in hosts treated with metabolites of aflatoxin B1 is similar to direct of indirect UV reactivation . Metabolites of aflatoxin B1 produce induced phage reactivation as well as prophage lambda induction in lysogens and cell filamentation in non-lysogens . These cellular events are also triggered by DNA lesions caused by UV radiation and result from the induction of a metabolic pathway (SOS functions) . We postulate that, in eucaryotes, carcinogens may induce cellular SOS functions similar to those in E . coli . Induction of such functions might be responsible for the transformation of mammalian cells.

Cell, 1977 Feb, 10(2), 275 - 85
Evolutionary drift of the argF and argl genes . Coding for isoenzyme forms of ornithine transcarbamylase in E . coli K12; Sens D et al.; Considerable genetic drift has occurred during the evolution of the two genes, argF and argl, which individually code for isoenzyme forms of ornithine transcarbamylase in E . coli K12 . The use of the experimental protocol described in this work established that between 25-40% of the base pairs in the genes argF and argl have changed since they diverged from a hypothetical ancestral gene . The extent of divergence of the genes was determined by mRNA-DNA hybridization utilizing arginine transducing DNA as a hybridization probe and mRNA prepared in vivo from appropriate bacterial strains and with mRNA synthesized in vitro using template DNA isolated from the specialized transducing phages gammacI857dargl and phi80dargF.

Arch Dis Child, 1977 Feb, 52(2), 152 - 4
Relapsing E . coli K1 antigen meningitis in a newborn; Helms PJ; A male infant of 32 weeks' gestational age who presented with recurrent apnoea on the second day of life was shown to have an Escherichia coli K1 antigen meningitis . Relapse occurred 6 days after an adequate systemic course of gentamicin and chloramphenicol and intrathecal gentamicin . This was successfully treated with intraventricular gentamicin and systemic cotrimoxazole . The need to maintain a high index of suspicion for meningitis in the newborn period and to treat adequately the frequently accompanying ventriculitis is emphasized.

Nucleic Acids Res, 1977 Feb, 4(2), 327 - 38
Fluoresceinylthiocarbamyl-tRNATyr: a useful derivative of tRNATyr (E.coli) for physicochemical studies; Pingoud A et al.; Fluoresceinylthiocarbamyl-tRNATyr (FTC-tRNATyr) is prepared from tRNATyr and fluoresceinisothiogyanate (FITC) under mildly alkaline conditions . Labelling occurs specificly at the base Q of tRNATyr . The modified tRNA is fully active in the aminoacylation assay; when aminoacylated it is recognized by the elongation factor Tu (EF-Tu) . Codon-anticodon interaction, however, is severely affected by the modification.

Mol Gen Genet, 1977 Jan 18, 150(2), 211 - 9
A suitable method for construction and cloning hybrid plasmids containing EcoRI-fragments of E . coli genome; Kozlov JI et al.; A convenient procedure for the isolation of specific EcoRI-fragments of E . coli genome and their amplification on Km-resistance plasmid victor CK delta11 is described . The hybrid molecules were constructued in vitro using EcoRI-digestion, followed by ligation . Then appropriated E . coli strain was transformed with ligated DNA mixture and hybrid plasmids CK delta11-arg+, CK delta11-his+, CK delta11-thr+ and CK delta11-leu+ containing loci of E . coli genome were selected by molecular cloning . The hybrid plasmids obtained consisted of one EcoRI-fragment of initial plasmid CK delta11 and one respective specific portion of E . coli genome.

Mol Gen Genet, 1977 Jan 7, 150(1), 21 - 8
Development of E.coli virus T1: the pattern of gene expression; Wagner EF et al.; T1 infected bacteria exhibit a distinct pattern of gene expression . The control of this expression is accessible to biochemical analysis . T1 induces the synthesis of 31 proteins in E . coli . The virion contains 15 proteins . By means of T1 amber mutants, 10 gene products have been assigned to specific T1 genes . Three classes of T1 proteins are defined by the kinetics of their syntheses: early, early-late and late proteins . The regulation of protein synthesis involes at least three mechanisms: for cessation of host gene expression, for discontinuation of the early class during the late phase and for induction of the late T1 proteins . The positive control of late gene expression is not coupled to replication . The host RNA-polymerase transcribes the viral genome throughout the infectious cycle . No virus coded RNA-polymerase is induced.

Antonie Van Leeuwenhoek, 1977, 43(2), 199 - 204
Characterization of the E . coli K12 strain AB1157 as impaired in guanine/xanthine metabolism; Hoekstra WP et al.; The widely used E . coli K12 strain AB1157 is impaired in guanine (xnathine) metabolism . Mutants blocked in purine biosynthesis before the stage of inosine monophosphate synthesis do not grow on external guanine or xanthine . The genetic nature of the Gua/Xan lesion is a deletion in the chromosome that covers the proA gene . The lesion causes reduced uptake of guanine.

Circ Shock, 1977, 4(2), 181 - 90
In vitro effects of E . coli endotoxin on fatty acid and lactate oxidation in canine myocardium; Liu MS et al.; We studied the in vitro effect of E . coli endotoxin on the oxidation of palmitate, palmitoyl CoA, and lactate by canine heart homogenate . Heart homogenates were incubated in calcium-free Krebs-Ringer-phosphate buffer in the presence of a 14C-labeled substrate . Oxidation of the individual substrate was calculated from the rate of 14CO2 production . The rate of oxidation of palmitate, palmitoyl CoA, and lactate was proportionally inhibited by increasing amounts (80-800 microgram) of endotoxin . The decrease in substrate oxidation could be mimicked by adding calcium chloride to the tissue preparation, and could be effectively prevented by the chelating agent, EDTA . Ionic calcium was released from tissue stores during incubation of the tissue preparation with endotoxin . These findings demonstrate that E . coli endotoxin inhibits substrate oxidation by heart homogenates when incubated under in vitro conditions . The data also suggest that the inhibition may be mediated by ionic calcium released from the tissue in response to the action of endotoxin.

Tsitol Genet, 1977 Jan-Feb, 11(1), 3 - 9
{Resistance to phage MS2 induced in E . coli by infection with that phage}; Pererva TP; A sensitive cell of E . coli AB 259 Hfr 3000 infected with RNA-containing phage MS2 produces phages and simultaneously continues to divide showing a segregation of sensitive cells which maintain new cycles of the infection . Phage multiplication in the sensitive cell induces phage-resistant forms in the progeny of this cell . The described phenomenon is not caused by selection of pre-existing F--cells, but may result from a direct interaction of phage products with the episomal DNA coding proteins for F-pili . The elucidation of the mechanisms of this phenomenon may pave the way to studies of the DNA- and RNA- containing genome interaction within the cell, the mechanisms of persistent infection and the causes of different degrees in phage virulence.

Z Allg Mikrobiol, 1977, 17(1), 3 - 6
{Bistability of pyruvate production by E . coli ML30 in continuous culture}; Bergter F et al.; The pyruvate production of E . coli ML30 in continuous cultures was investigated . In a glucose mineralsalt medium with ammonium as the limiting substrate two stable stationary states (bistability) of pyruvate concentration were obtained . The bistability was limited to dilution rates lower than 0.3 h-1 and connected with a decrease of the yield coefficient (Y Glc) from approximately 0.45 to approximately 0.1.

Biull Eksp Biol Med, 1977 Jan, 83(1), 24 - 5
{Role of substrate inductors in the mechanism of cortisol action on beta-galactosidase activity in different strains of E . coli k-12 and in rat liver}; Zhukov-Verezhnikov NN et al.; A comparative study of the effect of cortisone on the beta-galactosidase synthesis in E . coli K-12 strains with an induced (E . coli 200 PS/Iac), constitutive (E . coli ML-308), and superrepressed (E . coli 200is) type of the enzyme synthesis and in the cells of rat liver demonstrated that the hormone proper had no derepressive effect . An increase of the beta-galactosidase synthesis occurred only in the presence of specific substrate inductors . It is supposed that the principal link in the action mechanism of cortisone on the laclose operon of E . coli and the enzyme production in the cells of the rat liver is preliminary derepression of the genome areas by means of the substrate inductors.

Antibiotiki, 1977 Jan, 22(1), 78 - 81
{Results of an experimental study of the antitumor activity of 1-asparaginase from E . coli and Erw . carotovora}; Terent'eva TG et al.; The antitumour activity of the preparations of L-asparaginase from E . coli and Erw . carotovora with respect to lymphadenosis L-5178 and Yorker's carcinosarcoma (ascitic cariants) has been established . No difference in antitumour efficacy of the preparation of L-asparaginase obtained from E . coli and Erw . carotovora was noted.

Cell, 1977 Jan, 10(1), 121 - 30
Capacity of ribosomal RNA promoters of E . coli to bind RNA polymerase; Mueller K et al.; The rate of in vitro transcription of the rRNA genes of E . coli is more than 20 fold higher than the averaged transcription rate of other genome segments of the same size . This "preferential transcription" of rRNA genes reflects a high efficiency of their promoters in chain initiation . We show that the high initiation rate at rRNA promoters results from a high rate of RNA polymerase binding to these promoters as measured by the formation of heparin-resistant RNA polymerase-DNA complexes . The results indicate that the preferential binding of RNA polymerase to rRNA promoters is mainly due to their large binding capacity rather than to a high rate constant of polymerase binding to a single binding site . The polymerase binding capcity of rRNA promoters was estimated from the number of rRNA chains initiated by heparin-resistant complexes under conditions of template saturation and from the number of rRNA transcription units participating in the binding reaction . At least 30 RNA polymerase molecules were found to be protected from heparin per rRNA transcription unit . The rest of the genome (99.4%; possibly sufficient to encode 4000 nonribosomal RNA species) protects under these conditions 2000 enzyme molecules . These results suggest that a high multiplicity of RNA polymerase binding may be responsible for the high efficiency of rRNA promoters . The validity of this hypothesis is discussed.

Ciba Found Symp, 1977, (60), 187 - 96
The free radical in ribonucleotide reductase from E . coli; Sjoberg BM et al.; Protein B2, one of the subunits of ribonucleotide reductase from Escherichia coli, contains a stable free radical . It is characterized by a doublet e.p.r . signal centered around g = 2.0047 and a sharp peak at 410 nm in the optical spectrum . The radical has been assigned to a tyrosyl residue in the protein with its spin density delocalized over the aromatic ring . Protein B2 also contains two antiferromagnetically-coupled high-spin iron(III) atoms, which stabilize the free radical . Protein B1, the other subunit of ribonucleotide reductase, contains two binding sites for substrate molecules, which are the four common ribonucleoside diphosphates . It also contains two classes of allosteric effector-binding sites . ATP and deoxyribonucleoside triphosphates function as effectors . A one-to-one complex of proteins B1 and B2 forms the enzymically-active ribonucleotide reductase . The free radical is, most likely, part of the active site.

Allerg Immunol (Leipz), 1977, 23(1), 17 - 23
{Conjugation of bovine gammaglobulin to L-asparaginase (E . coli) (author's transl)}; Hadge D et al.; Bovine gammaglobulin-L-asparaginase conjugates were prepared with an enzymic activity of about 30 IU/mg . Glutardialdehyde was used as bifunctional reagent for the cross-linking in an optimal concentration of 0.16 mg/10 mg protein . The both components were found in the conjugates in a ratio of 1:1.5 . The recovery was about 25% of the initial protein amounts . The antigenic specificity of the globulin component decreased up to 60%, the enzymic activity also up to 60% by the conjugation.

Nucleic Acids Res, 1977 Jan, 4(1), 31 - 42
Aminoacylation of tRNA Trp from beef liver, yeast and E . coli by beef pancrease tryptophan-tRNA ligase . Stoichiometry of tRNATrp binding; Dorizzi M et al.; The Michaelis constants and the maximum velocities in the aminoacylation reaction of tRNATrp from beef liver, yeast and E . coli by pure beef pancreas tryptophan-tRNA ligase show that this mammalian enzyme recognizes and charges the two eucaryotic tRNAs with the same efficiency . The rate of aminoacylation of the procaryotic tRNATrp by the enzyme is three orders of magnitude lower . The pH optimum of aminoacylation is 8 for both eucaryotic tRNAs . The optimum magnesium concentration is different . The rate is maximum when magnesium concentration is stoichiometric to ATP concentration for tRNATrp from beef liver and 10 mM above ATP concentration for tRNATrp from yeast . The number of binding sites on the enzyme for the two eucaryotic tRNAs has been measured by equilibrium filtration on Sephadex G-100 and found equal to two.

Mol Gen Genet, 1976 Dec 8, 149(2), 145 - 50
E . coli membranes become permeable to ions following T7-virus-infection; Ponta H et al.; Infection of E . coli with the viruses T7 or T3 leads to a dramatic efflux of potassium ions . This ion efflux is caused by the virus particle since no concomitant protein synthesis is required . T7 mutants carrying deletions in the M-gene (Schweiger et al., 1975), however, yield virus particles disturbed in the ion release.

Biull Eksp Biol Med, 1976 Dec, 82(12), 1492 - 4
{Isolation of high molecular DNA of plasmids FBI and FBI drd from serologically typed strains of E . coli (AP1 and AP2)}; Kaliuzhnaia AP et al.; The authors elaborated a method of isolation of high molecular DNA from the plasmids FB1 and FB1drd of the conditionally pathogenic E . coli strains . Molecular weights of the isolated plasmid DNAs were determined by means of electrophoresis of the DNA fragments in agar gel and sedimentation in the neutral gradient of glycerine concentration.

Biull Eksp Biol Med, 1976 Dec, 82(12), 1487 - 8
{Nature of rec+ revertants isolated from E . coli K-12 cultures mutant with regard to gene rec A}; Naumova OB; The nature of Rec+ revertants isolated from the E . coli K-12 AB 2463 recA13 defective strain cultures was ascertained by transduction of the recA gene region into the cells of the JC 2915F- strain with the aid of P1 vira phage . Then the recombination capacity of the transductants was tested by crossing with the JC 158 Hfr strain, and the UV sensitivity of the transductants was determined . Besides, the response of the transductants to the suppression phages was examined . As revealed, the REc+ revertants were characterized by differences in the recA gene . In a number of Rec+ revertants phenotype Rec+ appeared as a result of reverse mutation in this gene from rec- to rec+, whereas in other revertants Rec+ phenotype was due to indirect suppression.

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