Escherichia coli

Mol Gen Genet, 1978 Nov 16, 167(1), 75 - 82
Analysis of regulatory mechanisms controlling the activity of the hexitol transport systems in Escherichia coli K12; Lengeler J et al.; The transport systems (enzymeII-complexes of the PEP-dependent sugar:phosphotransferase system) coded for in the mtl and in the gut (srl) operon of E . coli K12 have been shown to be the pacemaker enzymes in the catabolism of the two hexitols D-mannitol and D-glucitol, respectively . As for other pacemaker enzymes their activity is regulated in a complex way: (i) via competitive inhibition by analogues . (ii) via non-competitive (feedback) inhibition by the simultaneous, rapid uptake of a number of structurally related or non-related carbohydrates, regardless if these are transported by group translocation, active transport or facilitated diffusion . This type of inhibition is strongly reinforced, if the inhibitory carbohydrates are converted efficiently into hexose-phosphates at the same time . Among these, predominantly D-fructose-6-P seems to act as a feedback inhibitor for the hexitol specific enzymeII-complexes: (iii) inhibition of hixitol-phosphate accumulation by D-glucose-6-P . The influence of additional parameters (PEP level, P approximately HPr level) and indications for the existence of further mechanisms controlling the activity of hexitol and other carbohydrate transport systems will be discussed, as will be the part the inhibitory mechanisms described above play in the phenomena of transient repression and inducer exclusion.

Mol Gen Genet, 1978 Nov 16, 167(1), 21 - 8
Altered DNA-protein relaxation complex in a replication mutant of plasmid ColE1; Collins J et al.; Approximately 200,000 clones of Escherichia coli carrying mutagen-treated colicinogenic plasmid E1 (ColE1) were examined for irreversible loss of the plasmid at 43 degrees . Thirty of these clones that appeared to be most defective in plasmid DNA replication at the non-permissive temperature were selected for the study of: (a) the kinetics of plasmid and chromosomal DNA replication during a temperature shift in either the presence or absence of chloramphenicol; (b) the temperature stability of the plasmid DNA-protein relaxation complex; and (c) the temperature effect on F-promoted conjugal transfer . Two mutant plasmids, pJC307 and pJC301, showed defects in their relaxation complex . The relaxation complex of pJC307 exhibited an altered temperature stability in vitro . Reversion to temperature resistant replication resulted in four out of five cases in a concomitant change in the temperature stability of the relaxation complex . Conjugal mobility of this mutant was not markedly reduced at the permissive or non-permissive temperature . Plasmid pJC301 could not be isolated in the form of a relaxation complex and it was very poorly mobilized in an F'-promoted conjugation . These results indicate that the ColE1 plasmid codes for at least one of the proteins of the relaxation complex and that the relaxation complex is involved in ColE1 DNA replication . In addition, the properties of the mutant plasmid pJC301 are consistent with a role for the complex in the mobilization of ColE1 during conjugation.

Mol Gen Genet, 1978 Nov 16, 167(1), 113 - 8
Nitrite reduction in Escherichia coli: genetic analysis of nir mutants; Abou-Jaoude A et al.; Five mutants of Escherichia coli impaired on nitrite reduction were studied . All have lost NADH-nitrite reductase activity but have retained the capacity to synthesize all or part of their cytochrome c552 . Three genes, nir C, nir D, and nir E were mapped at 26, 72.5 and 49.5 min, respectively . Another gene, nir F was tentatively localized around 52 min.

Biochem J, 1978 Nov 15, 176(2), 553 - 61
Characterization of an Escherichia coli K12 mutant that is sensitive to chlorate when grown aerobically; Giordano G et al.; Escherichia coli can normally grow aerobically in the presence of chlorate; however, mutants can be isolated that can no longer grow under these conditions . We present here the biochemical characterization of one such mutant and show that the primary genetic lesion occurs in the ubiquinone-8-biosynthetic pathway . As a consequence of this, under aerobic growth conditions the mutant is apparently unable to synthesize formate dehydrogenase, but can synthesize a Benzyl Viologen-dependent nitrate reductase activity . The nature of this activity is discussed.

Experientia, 1978 Nov 15, 34(11), 1483 - 4
Endotoxemia and adrenaline-hyperreactive death in mice; Kuratsuka K et al.; Mice given i.v . a sublethal dose of endotoxin in advance died with shock-like symptoms on administration of sublethal adrenaline dose . The lethal adrenaline-hyperreaction induced by endotoxin appeared gradually within a few h, showed maximum response after several h and almost disappeared 24 h after endotoxin administration.

Biochem J, 1978 Nov 15, 176(2), 569 - 72
The acidic ribosomal phosphoprotein of eukaryotes and its relationship to ribosomal proteins L7 and L12 of Escherichia coli; Leader DP et al.; The acidic ribosomal phosphoprotein, Lgamma, of Krebs II ascites cells was further characterized and compared with proteins L7 and L12 of Escherichia coli . Ribosomal protein Lgamma was selectively removed from 60S sibosomal subunits by 50% ethanol and 1M-NH4Cl, and antibodies raised against protein Lgamma cross-reacted with E . coli protein L12 in immunodiffusion experiments . These and other, previously reported, data support the proposal that the uekaryotic counterpart of E . coli proteins L7 and L12 is phosphorylated.

Biochemistry, 1978 Nov 14, 17(23), 4894 - 9
Joining of 3'-modified oligonucleotides by T4 RNA ligase . Synthesis of a heptadecanucleotide corresponding to the bases 61--77 from Escherichia coli tRNAfMet; Ohtsuka E et al.; Chemically synthesized fragments corresponding to the 3' end of tRNAfMet from Escherichia coli were joined by T4-induced RNA ligase to yield a heptadecanucleotide (bases 61--77) . The 3' terminus of C-C-A was modified by introduction of the ethoxymethylidene group to prevent intra- and intermolecular self-joining reactions at the 3' end . The terminal trimer was phosphorylated using polynucleotide kinase and joined to C-A-A with RNA ligase . The hexamer {C-A-A-C-C-A(ethoxymethylidene)} corresponding to bases 72--77 was obtained in a yield of 60% . An undecanucleotide (bases 61--71) which had been synthesized in a yield of 34% by similar enzymatic joining of U-C-C-G-G to pC-C-C-C-C-G was allowed to react with the 5'-phosphorylated hexamer (bases 72--77) using an excess of RNA ligase to yield the heptadecanucleotide U-C-C-G-G-C-C-C-C-C-G-C-A-A-C-C-A (bases 61--77) . The product was identified by homochromatography and nearest neighbor analysis.

Biochemistry, 1978 Nov 14, 17(23), 5038 - 45
Tyrosyl-base-phenylalanyl intercalation in gene 5 protein-DNA complexes: proton nuclear magnetic resonance of selectively deuterated gene 5 protein; Coleman JE et al.; The interactions of oligodeoxynucleotides with the aromatic residues of gene 5 protein in complexes with d(pA)8 and d(pT)8 have been determined by 1H NMR of the protein in which the five tyrosyl residues have been selectively deuterated either in the 2,6 or the 3,5 positions . Only the 3,5 protons of the three surface tyrosyls (26, 41, and 56) interact with the bases . The remainder of the aromatic protons undergoing base-dependent upfield ring-current shifts on complex formation are phenylalanyl protons, assigned to Phe(13) on the basis of model building . 19F NMR of the complexes of the m-fluorotyrosyl-labeled protein with d(pT)4 and d(pA)8 confirms the presence of ring-current perturbations of nuclei at the 3,5-tyrosyl positions of the three surface tyrosyls . Differential expression of the 19F(1H) nuclear Overhauser effect confirms the presence of two buried and three surface tyrosyl residues . A new model of the DNA binding groove is presented involving Tyr(26)-base-Phe(13) intercalation.

J Biol Chem, 1978 Nov 10, 253(21), 7826 - 31
The molecular mechanisms of dicarboxylic acid transport in Escherichia coli K12 . The role and orientation of the two membrane-bound dicarboxylate binding proteins; Lo TC et al.; Previous communications from this laboratory have indicated that dicarboxylic acid transport in Escherichia coli is an active process, and that at least three genes are responsible for this transport system . In attempts to identify the transport components, one periplasmic binding protein and two membrane integral proteins (SBP 1 and SBP 2) were implicated to participate in the transport system in vivo . In the present communication, we demonstrate, through biochemical analysis of the transport mutants, that the two membrane transport genes, dctA and dctB, are responsible for the two membrane-bound dicarboxylate binding proteins, SBP 2 and SBP 1, respectively . We also find that the substrate recognition sites of SBP 1 and SBP 2 are exposed to the inner and outer surfaces of the membrane, respectively . This may have important implications for the role of SBP 1 and SBP 2 in the translocation process.

J Biol Chem, 1978 Nov 10, 253(21), 7804 - 6
Rapid solid phase isolation of 20 specific tRNAs from Escherichia coli; Goss DJ et al.; A solid phase procedure has been developed for the rapid isolation of all 20 species of tRNA from Escherichia coli . The overall yields for a single preparation cycle ranged from 62 to 96%, the average being 80% . The values for the amino acid acceptor activities of the tRNA species equaled those reported in the literature for highly purified tRNAs . Starting from crude tRNA, a given tRNA species can easily be isolated in less than 2 h . One milliliter of the resin, which is reusable, is sufficient for the isolation of 200 mg of a specific tRNA . The procedure requires a bifunctional reagent, one moiety of which (--SO2Cl) reacts with the amino acid on the aminoacylated tRNA, the other, with the --SH group on the resin . Thus, only the desired tRNA species is bound to the resin; any of the other tRNAs in the filtrate can be isolated in another cycle . Raising the pH results in deacylation and release from the resin of the desired tRNA species . For tRNA Cys, it is necessary to block the --SH of cysteine prior to reaction with the bifunctional reagent . Side reactions involving the bifunctional reagent . Side reactions involving the bifunctional reagent and tRNA are either easily reversible or negligible (less than 0.01%).

J Biol Chem, 1978 Nov 10, 253(21), 7731 - 7
In vitro depolarization of Escherichia coli membrane vesicles by colicin Ia; Tokuda H et al.; Conditions are reported under which membrane vesicles prepared from Escherichia coli K12 are depolarized by colicin Ia . Although incubation of membrane vesicles with active colicin Ia affects neither transport activity nor the ability of such vesicles to generate a deltapH or deltapsi, a single freeze-thaw cycle of such vesicles in the presence of colicin Ia leads to 1) retention of the colicin by the vesicles, 2) inactivation of transport activity, and 3) membrane depolarization, with a concomitant increase in the transmembrane deltapH . These effects are dependent upon the presence of active colicin Ia during the freeze-thaw cycle . These findings are consistent with our previous results showing that Ia-treated whole cells or membrane vesicles prepared from such cells are defective in their ability to generate a deltapsi, yet generate an increased deltapH (Tokuda, H., and Konisky, J . (1978) Proc . Natl . Acad . Sci . U . S . A., 75, 2579--2583) . In addition to its effect on vesicles prepared from sensitive cells, we show that vesicles prepared from both colicin Ia-resistant and -tolerant cells are depolarized by colicin treatment with a concomitant increase in deltapH . It is concluded that the final target of colicin Ia is the cytoplasmic membrane . A model for the mechanism of colicin Ia action is presented in which colicin Ia binds to the specific colicin Ia outer membrane receptor and is subsequently translocated to the cytoplasmic membrane where its integration leads to the formation of ion channels.

J Biol Chem, 1978 Nov 10, 253(21), 7972 - 9
Reconstitution of escherichia coli succinoxidase from soluble components; Reddy TL et al.; 1 . The membrane-bound succinoxidase of Escherichia coli was fractionated with deoxycholate into three soluble components, viz . succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase complex, and a factor identified as a phospholipid-containing component . 2 . The dehydrogenase and cytochrome oxidase complexes were partially purified by filtration on Amicon membranes, Sepharose 4B chromatography, and sucrose gradient centrifugation . 3 . Reconstitution of membranous succinoxidase, which catalyzes the oxidation of succinate by molecular oxygen by an integrated CN(-)-sensitive pathway, was achieved by mixing the soluble succinate dehydrogenase.cytochrome b1 complex with the soluble cytochrome oxidase complex in the presence of deoxycholate and then removing the detergent by gel filtration on Sephadex G-75 . The phospholipid-containing factor stimulated the formation of succinoxidase by about 100% over that observed with the two complexes . 4 . Isopycnic sucrose gradient centrifugation of succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase, and the reconstituted succinoxidase gave buoyant densities (p value) as 1.167, 1.229, and 1.194, respectively . 5 . Electron microscopic evidence is presented for the vesicular nature of the reconstituted succinoxidase.

J Biol Chem, 1978 Nov 10, 253(21), 7738 - 43
A novel phosphodiesterase from Aspergillus niger and its application to the study of membrane-derived oligosaccharides and other glycerol-containing biopolymers; Schneider JE et al.; A novel phosphodiesterase has been found in commercially available extracts of Aspergillus niger and has been partially purified by fractionation with acetone and chromatography on carboxymethylcellulose . The enzyme attacks glycerophosphodiester bonds with the liberation of free glycerol only . The synthetic substrate glucose 6-phospho-sn-1'(3')-glycerol is hydrolyzed with production of equivalent amounts of free glycerol and glucose 6-phosphate . Similarly, the enzymic hydrolysis of sn-glycero-3-phosphocholine liberates glycerol and phosphocholine . The hydrophilic head groups of membrane phospholipids of Escherichia coli are continuously transferred to a closely related family of oligosaccharides ("membrane-derived oligosaccharides") containing glucose as the sole sugar (van Golde, L . M . G., Schulman, H., and Kennedy, E . P . (1973) Proc . Natl . Acad . Sci . U . S . A . 70, 1368--1372) . Oligosaccharide A-2 contains sn-1-glycerophosphate residues (derived from phosphatidylglycerol) in phosphodiester linkage . Treatment of this oligosaccharide with the phosphodiesterase led to the liberation of nearly all of the glycerol as free glycerol . Subsequent partial acid hydrolysis of the enzyme-treated oligosaccharide led to the recovery of glucose 6-phosphate in almost quantitative yield . The sn-1-glycerophosphate residues are therefore linked to position 6 of glucose units of the oligosaccharide . The activity of the enzyme is not restricted to glycerophosphodiesterases since it will hydrolyze phosphodiesters containing other polyols such as the synthetically prepared glucose 6-phospho-DL-1'(2'-hydroxy-3'-ethoxy)propane.

Mol Gen Genet, 1978 Nov 9, 166(3), 305 - 12
Isolation and characterization of a ColE1 plasmid containing the entire bio gene cluster of Escherichia coli K12; Cohen G et al.; ColE1amp plasmids carrying the entire bio gene cluster were constructed in vitro using ColE1amp as the cloning vehicle and a lambda transducing phage, lambdaatt2, as the source of bio DNA . Restriction endonuclease EcoRI digests of ColE1amp and lambdaatt2 DNA were joined by polynucleotide ligase and plasmids bearing the entire bio gene cluster were selected, after transformation, in bio deletion strains of E . coli . Recombinant DNA molecules contained one ColE1amp fragment (7.4 X 10(6) daltons) and one lambdaatt2 DNA fragment (5.4 X 10(6) daltons) . Clones carrying ColE1 amp-bio plasmids produce elevated levels of biotin and biotin synthetase activity.

Mol Gen Genet, 1978 Nov 9, 166(3), 299 - 304
Map location of the Escherichia coli origin of replication; Marsh RC; Working with restriction fragments obtained directly from the Escherichia coli K12 chromosome, the EcoRI-HindIII restriction map of the section of the chromosome containing the replication origin has been extended by 14 kilobase pairs (kb) to cover 56 kb . Within this newly mapped portion, the ilv and rrnC cistrons have been identified by (1) hybridization of individual restriction fragmanents to the ilv-transducing phage lambdadilv5 and (2) a comparison of the restriction map of this region with the EcoRI map of lambda dilv5 and the Hind III map of the plasmid pJC110, a ColEl-ilv hybrid . The replication origin is located approximately 30 kb from the ilvE gene and 20 kb from the rrnC 16S rRNA cistron . This places the origin near 82.7 min on the genetic map, close to uncA.

Mol Gen Genet, 1978 Nov 9, 166(3), 245 - 9
Restriction enzyme cleavage of DNA resulting from gently lysed Escherichia coli; Valenzuela MS et al.; When E . coli or lambda infected E . coli are gently lysed the DNA is released as a very fast sedimenting species that is presumably bound to membrane material . If this complex is now subjected to restriction enzyme cleavage, only a minor fraction of the fast sedimenting DNA remains and this is found, after purification, to be enriched for branched molecules.

Mol Gen Genet, 1978 Nov 9, 166(3), 313 - 20
Regional preference of insertion of Tn501 and Tn802 into RP1 and its derivatives; Grinsted J et al.; The sites of insertion of Tn501 into RP1 and into derivatives of this plasmid that either lack the Tn801 (TnA) element or contain it in a different location have been determined . Similarly, the sites of insertion of Tn802 into a derivative of RP1 that lacks the Tn801 element and into recombinants of this plasmid with Tn501 were determined . 'Hot spots' for insertion were observed with both transposons; but it is clear that a particular DNA sequence is not sufficient to define a 'hot spot', since a particular region does contain many insertions when present in one plasmid but does not do so when part of another.

Lancet, 1978 Nov 4, 2(8097), 963 - 5
Early splenomegaly in homozygous sickle-cell disease: An indicator of susceptibility to infection; Rogers DW et al.; 135 children with homozygous sickle-cell (SS) disease diagnosed at birth have been followed for 1--5 years . Severe bacterial infections were confined to those in whom the spleen was first palpable at or before 1 year of age and were commonest in those in whom the spleen was first palpable at or before age 6 months . Regular follow-up of children with SS disease diagnosed at birth will identify children particularly at risk of severe infections.

Eur J Biochem, 1978 Nov 2, 91(1), 303 - 10
Rapid purification of plasmid DNAs by hydroxyapatite chromatography; Colman A et al.; A method is described for the rapid preparation of plasmid DNAs of molecular weight up to 14 X 10(6) . This method involves the chromatography, at room temperature, of bacterial cleared lysates on hydroxyapatite in the presence of high concentrations of phosphate and urea . All detectable protein and RNA contamination of plasmid DNA is removed by this procedure and the conformation of the plasmid DNA is unaffected . Less than 0.5% chromosomal DNA is present in the purified preparation and even this can be removed if necessary by a simple extention of the procedure to include a heat-denaturation step . The method is extremely rapid and amenable to large-scale plasmid preparation; 5 mg ColE1 DNA have been purified within 40 min . The yield of plasmid DNA is similar to that obtained with the conventional dye-centrifugation technique, however the purity is greater.

Fortschr Med, 1978 Nov 2, 96(41), 2059 - 63
{New aspects of the value of endotoxins in various gastrointestinal diseases}; Schussler P et al.; Recent investigations of several authors on portal venous and systemic endotoxemia in healthy adults have shown that endotoxins absorbed from the intestinal mucosa are found in portal venous blood, cleared by the RES of the liver and usually cannot be determined in peripheral blood . In patients with liver disease, however, there was often a reduced endotoxin clearance with spillover of endotoxin resulting in systemic endotoxemia . Among the complications of systemic endotoxemia, hepatocytotoxicity, pyrogen reaction, disseminated intravascular coagulation, impaired renal function, and endotoxic shock are most hazardous . In addition, O-antibody titers and lipid-A-antibody titers were found to be higher in patients with liver disease and in patients with Crohn's disease than in control groups . The investigations indicate that intestinal endotoxins are of importance in the pathogenesis of liver disease and of Crohn's disease and that reduction of intestinal endotoxins by antibiotics may be of value in the therapy of these diseases.

Muscle Nerve, 1978 Nov-Dec, 1(6), 467 - 70
HLA, anti-DNA, and complement in myasthenia gravis; Christiansen FT et al.; Twenty-seven patients (18 females and 9 males) with myasthenia gravis were HLA-A, -B, -C, and -D typed, and the results were analyzed with relation to evidence of immunodeficiency, thymic disease, and associated autoimmune processes . An association of A1, B8, and DRW3 appeared to identify a group of 8 females with higher mean anti-DNA, lower mean C4, and lower mean E . coli antibody titer than other females in whom CW4 (with or without BW35) was common (6 of the remaining 10 females were in this category) . Antiacetylcholine receptor (anti-AChR) autoantibody and reduced serum IgM and isohemagglutinin titers were not clearly related to particular HLA specificities . These results suggest that HLA-A1, -B8, -DRW3, and -CW4 may be related to associated phenomena rather than playing a major role in the development of anti-AChR and myasthenia gravis.

Vopr Virusol, 1978 Nov-Dec, (6), 664 - 9
{Mapping of lengthy changes in the genomes of lambda-phages by using restriction endonucleases}; Kalinin VN et al.; Fragmentation and mapping of DNA of two derivatives of lambda-phage, lambdapgal and lambda delta were done using restricting endonucleases R . EcoRI, R . BamHI, and R . SmaI . In DNA of lambdapgal phage a fragment of chromosome lambda of the wild type with molecular mass of 3.7--4.7 megadaltons to the left of the integration site was replaced with a fragment of chromosome of E . coli with the molecular mass of 2.3--3.3 MD containing a complete galactose operon . In the chromosome of lambda delta phage as compared with lambda-phage of the wild type there is a deletion of 5.2 MD in size . The localization of the deletion was determined . Possible ways of using DNA of lambdapgal in genetic engineering studies as the "pure" source of gal-operon for its transplantation using various restricting endonucleases are discussed.

Mutat Res, 1978 Nov, 58(2-3), 175 - 81
Comparative studies of chromosomal aberration and mutagenicity of the trivalent and hexavalent chromium; Nakamuro K et al.; The comparative cytogenetic and mutagenic effects between trivalent and hexavalent chromium were investigated . Five chromium compounds, K2Cr2O7 and K2CrO4 containing Cr6+, and Cr(CH3COO)3, Cr(NO3)3 and CrCl3 containing Cr3+, were examined for their ability to induce chromosomal damage in cultures of human leukocytes, for their reactivity with DNA by a rec-assay system and for mutagenicity in the E . coli Hs30R test system . Chromosome-breaking activity was significantly higher for the compounds with hexavalent than trivalent chromium, the efficiency being in the decreasing order K2Cr2OM greater than K2CrO4 greater than Cr(CHCOO)3 greater than Cr(NO3)3, CrCl3 . In the rec-assay and mutation assay, hexavalent (K2Cr2O7 and K2CrO4) and trivalent Cr(CH3COO)3) compounds gave positive results, their mutagenic potential being higher in the same order of clastogenic magnitude.

Biochem J, 1978 Nov 1, 175(2), 461 - 5
Phosphonate analogues of aminoacyl adenylates; Southgate CC et al.; Phosphonomethyl analogues of glycyl phosphate and valyl phosphate, i.e . NH2-CHR-CO-CH2-PO(OH)2, were synthesized and esterified with adenosine to give analogues of aminoacyl adenylates . The interaction of these adenylate analogues with valyl-tRNA synthetase from Escherichia coli was studied by fluorescence titration . The analogue of valyl phosphate has an affinity for the enzyme comparable with that of valine, but that of valyl adenylate is bound much less tightly than either valyl adenylate or corresponding derivative of valinol . The affinity of the analogue of glycyl adenylate was too low to be measured . We conclude that this enzyme interacts specifically with both the side chain and the anhydride linkage of the adenylate intermediate.

Nucleic Acids Res, 1978 Nov, 5(11), 4065 - 75
A new RNA-RNA crosslinking reagent and its application to ribosomal 5S RNA; Wagner R et al.; The synthesis of a new RNA specific bifunctional crosslinking reagent, 1.4-phenyl-diglyoxal, is described which reacts exclusively with guanosines . The properties of the crosslinked products enabled us to develop a straightforward method for identifying the reacted nucleotides . Results obtained with ribosomal 5S RNA of Escherichia coli demonstrate the formation of an intramolecular crosslink between guanosine-2 and guanosine-112 in the stem region.

J Clin Lab Immunol, 1978 Nov, 1(3), 261 - 8
The response of young chronically protein-deficient mice to multiple antigenic challenge; Price P; Responses to two or more antigens given together or separated by an interval of up to four days were determined in young mice maintained from weaning on a 4% albumin diet, and compared with those of normally-fed controls . Simultaneous challenge with several antigens did not affect antibody production in mice of either dietary group ("Simultaneous Competition") and the responses of normal and protein-deficient mice to sheep or rat erythrocytes were similarly produced by the prior injection of horse or sheep cells ("Sequential Competition") . However, the low protein diet broadened the conditions under which primary and secondary injections of diphtheria toxoid impaired primary responses to tetanus toxoid . These findings are discussed in relation to mechanisms previously proposed to explain antigenic competition, with a view to explaining the effects of protein-deficiency on antibody production.

Biol Bull Acad Sci USSR, 1978 Nov-Dec, 5(6), 721 - 8
Balance of DNA and protein syntheses, processes of stabilization and repair of breaks in DNA strands, and cell viability; Fradkin GE et al.; The dependence of the stabilization and repair of breaks in the DNA strands on the balance of the syntheses of DNA and protein and the relationship of these processes to the viability of E . coli cells were experimentally substantiated . It was established that equilibrium of the rates of DNA and protein syntheses is a necessary condition for the functioning of processes of DNA repair . "Imbalanced" breaks in the DNA strands in vivo are a consequence of a sharp decrease in the effectiveness of DNA repair processes.

Mol Biol (Mosk), 1978 Nov-Dec, 12(6), 1313 - 8
{Selective binding of oligoribonucleotides by T7 phage induced RNA-polymerase}; Savinkova LK et al.; It was shown previously that E . coli RNA-polymerase being incubated with the random oligonucleotide mixtures of definite length binds certain oligoribonucleotides with the length greater than or equal to 5 nucleotides . The data presented demonstrate that T7 phage induced RNA-polymerase (T7 RNA-polymerase) also binds selectively oligoribonucleotides beginning from pentaribonucleotides . From the random mixtures of penta-, hexa-, hepta-, octa-, nona- and decaribonucleotides the hepta- and octaribonucleotides are bound most efficiently . The T7 RNA-polymerase bound oligoribonucleotides can be completely extracted from the random mixture by the addition of the redundant enzyme amounts . As far as E . coli RNA-polymerase and T7 RNA-polymerase do not compete for the oligoribonucleotides the conclusion is made that they bind different oligoribonucleotides . The addition of the T7 DNA to the previously formed T7 RNA-polymerase--heptaribonucleotide complex competitively displace the heptaribonucleotides from the complex; the competitive effect of T4 DNA is very low . The data suggest that the oligoribonucleotides which are selectively bound by the RNA-polymerase are attached to the enzyme site responsible for the interaction with the promotor.

Mikrobiologiia, 1978 Nov-Dec, 47(6), 1117 - 20
{Use of ultrasound to obtain small Escherichia coli cells containing drd plasmids}; Perebitiuk AN et al.; Treatment with ultrasound of Escherichia coli K-12 chi 1100 producing mini-cells and containing R factor 100-1 drd depressed in conjugation transfer, prior to defferential and zonal centrifugation, makes it possible to increase the yield and purity of mini-cells . Combination of ultrasound treatment with differential centrifugation produces mini-cells with purity greater than 10(3) per parent cell . Ultrasound has no negative effect on the physiological state of mini-cells and the hydrodynamical characteristics of segregated plasmid DNA.

Gene, 1978 Nov, 4(3), 261 - 78
Isolation, cloning and characterization of argF gene DNA from Escherichia coli K-12; Moore SK et al.; A 1650 base pair (BP) fragment carrying the entire argF structural gene with its associated control regions was isolated from an EcoRI/BamHI digest of phi80argFilambda cI857 DNA . This segment was cloned using the EcoRI and BamHI cleavage sites in the plasmid pBR322 . A preliminary restriction map of the argF region was prepared . RNA polymerase binding studies indicated that the argF promoter is located approx . 30 base pairs from the EcoRI terminus of the cloned DNA segment.

Can J Microbiol, 1978 Nov, 24(11), 1387 - 94
Further taxonomic characterization of the genus Bdellovibrio; Torrella F et al.; Cultures of Bdellovibrio isolated from different geographic locations have been studied in terms of deoxyribonucleic acid analysis (% G + C, genome size, and DNA hybridization), cytochrome spectrum, and host range . Isolates of the genus exhibit a broad range of % G + C ranging from 37 to 51% and the genome sizes extend from 1300 x 10(6) to 1700 x 10(6) daltons . DNA hybridization continues to reveal a high level of genetic heterogeneity . Bdellovibrio 3294 exhibits 32% relative reassociation to Bdellovibrio W, 37% to Bdellovibrio stolpii Uki2, and an undetectible level to Bdellovibrio starrii A3.12 Bdellovibrio W is 23% related to B . starri A3.12 and 28.5% to B . stolpii Uki2 . For the first time differential absorption techniques have revealed peaks of cytochrome b . The analysis of the cytochrome spectrum seems to be limited as a taxonomic tool since most of the recent isolates studied share a common cytochrome spectrum . Host-range studies have been found to be dependent on the experimental conditions, and with the exception of one isolate (B . starrii A3.12) the taxonomic significance of such techniques must be taken with caution.

Mutat Res, 1978 Nov, 52(2), 161 - 9
In vitro breakage of plasmid DNA by mutagens and pesticides; Griffin DE 3rd et al.; Covalently closed circular molecules of the colicinogenic plasmid E1 can serve as sensitive indicators for detecting in vitro breakage of DNA . After these molecules are radioactively labeled and purified by cesium chloride density-gradient centrifugation, they are incubated with the compounds to be tested . Samples are analyzed on alkaline sucrose gradients to determine the fraction of unbroken molecules and a breakage rate is calculated . Positive results were obtained for all three mutagenic alkylating agents (MMS, EMS, and MNNG) and of the 11 pesticides tested, dexon, dichlorvos, malathion, and methyl parathion induced breaks in molecules at a rate significantly greater than the controls.

Can J Biochem, 1978 Nov, 56(11), 1006 - 15
Bis-intercalative binding to DNA of novel bis(10-methyl)acridinium chlorides and its dependence on chain length of linker; Lown JW et al.; The synthesis of a series of novel bis(10-methyl)acridinium compounds (both unsubstituted and the 6-chloro-2-methoxy substituted) linked by methylene bridges of lengths from (CH2)4 to (CH2)12 and in one case by spermine is described . Their ability to bind to duplex DNA was compared by their relative inhibition of E . coli DNA polymerase catalyzed DNA synthesis . It was determined that they function as DNA template inhibitors and do not affect the DNA polymerase directly . Their ability to function as bis-intercalators was assessed by a novel and convenient topoisomerase fluorescent assay . It was concluded that whereas the (CH2)4-linked compounds act only as monofunctional intercalators because of steric constraints the (CH2)6-, (CH2)8-, and (CH2)10-linked substituted bisacridinium compounds, as well as the (CH2)10- and (CH2)12- unsubstituted analogues, function as bis-intercalators with DNA.

Zentralbl Bakteriol {Orig A}, 1978 Nov, 242(2), 206 - 15
{Therapeutic studies on two different models of experimental pyelonephritis (author's transl)}; Schulz E et al.; By transurethral instillation of a suspension of a serum resistant E . coli strain (serotype O25:19:12), chronic pyelonephritis is induced in rats, if systemic and local defense mechanisms are impaired by estradiol application . Without hormonal treatment a similar infection can be achieved with a more virulent E . coli strain (serotype O2:1:4) . Due to the chronic course of the renal infection in either model, beginning of therapy may be delayed (e.g., 10 days after infection) thus imposing difficult therapeutic conditions on the efficacy of antibiotics to be tested . Evaluation of antibiotics in both models produced differential therapeutic results . In spite of equal MIC's for the applied E . coli strains, gentamicin and particularly cefazolin treatment was less effective in the estradiol treated rats than in those without hormone application . Cefuroxime therapy produced favourable results in either model . The different therapeutic efficacy in both models is to be explained by differences in host resistance to infection . It is suggested that by simultaneans testing of antibiotics in either model, it will be possible to estimate to what extent the therapeutic efficacy of antibiotics depends on the support of intact host defense mechanisms.

Scand J Haematol, 1978 Nov, 21(5), 403 - 10
The mechanism of endotoxin-induced hypoferraemia; Torrance JD et al.; The effect of endotoxin on the processing of erythrocyte iron by reticuloendothelial cells of the liver and spleen was studied in rats using heat damaged erythrocytes labelled with 59Fe . Endotoxin did not alter the uptake of the damaged cells but markedly inhibited the subsequent early phase of iron release from the reticuloendothelial cells . The inhibition seemed to be due to both a decreased rate of labelled haem destruction and an increased incorporation of radioiron into ferritin . Although early iron release was decreased 0--2 h after endotoxin administration, the diversion of iron into ferritin was more marked when endotoxin was given 18 h before . The block in iron release was partially overcome in animals that had been kept on an iron free diet or had been phlebotomised . In these animals the decreased rate of haem catabolism remained unaltered but less iron was diverted into ferritin.

J Biochem (Tokyo), 1978 Nov, 84(5), 1165 - 9
An enzyme activity specific for nitrous acid-treated DNA in Escherichia coli; Oeda K et al.; An enzyme activity specifically active on nitrous acid-treated DNA was found in an extract of Escherichia coli . The enzyme acts on both double- and single-stranded DNAs, treated with nitrous acid, in the presence of EDTA, although the former DNA is a better substrate . Evidence is presented that nitrous acid- and bisulfite-induced types of damage in DNA are recognized by different enzymes: (1) Uracil-DNA glycosylase, purified 250-fold from E . coli 1100, attacks bisulfite-treated DNA but not nitrous acid-treated DNA . (2) Almost equal levels of activity toward nitrous acid-treated DNA were found in wild-type and uracil-DNA glycosylase-deficient strains of E . coli.

J Biochem (Tokyo), 1978 Nov, 84(5), 1155 - 64
Role of uracil-DNA glycosylase in the repair of deaminated cytosine residues of DNA in Escherichia coli; Hayakawa H et al.; Uracil-DNA glycosylase, which acts specifically on uracil-containing DNA, was purified 250-fold from an extract of Escherichia coli 1100 . The enzyme releases free uracil from DNA, producing alkali-labile apyrimidinic sites in the DNA . The enzyme is active on both native and heat-denatured DNA of phage PBS1, which contains uracil in place of thymine . piX174 DNA which had been treated with bisulfite and then at alkaline pH was susceptible to the action of uracil-DNA glycosylase . Since DNA treated with bisulfite alone was less susceptible to the enzyme, it is likely that the enzyme recognizes deaminated cytosine, namely uracil, but not bisulfite adducts of uracil and cytosine in the treated DNA . DNA treated with nitrite or hydroxylamine was not attacked by the enzyme . Enzyme activity acting on bisulfite-treated DNA was absent from an extract of E . coli mutant BD10 (ung) . The mutant exhibited higher sensitivity to bisulfite than did the wild-type strain and was unable to reactivate phage T1 pre-exposed to bisulfite and weak alkali.

Infect Immun, 1978 Nov, 22(2), 462 - 72
Differences in hydrophobic surface characteristics of porcine enteropathogenic Escherichia coli with or without K88 antigen as revealed by hydrophobic interaction chromatography; Smyth CJ et al.; Porcine enteropathogenic Escherichia coli strains possessing or lacking K88 antigen were studied by using hydrophobic interaction chromatography on cross-linked agarose gels with alkyl or aryl substituents (amphiphilic gels) to determine whether or not they possessed surface-associated hydrophobic properties . Strains with K88ab or K88ac antigen adsorbed to phenyl and octyl Sepharose gels in the presence of 4 M sodium chloride . This property correlated with phenotypic expression of K88 antigen . Cells grown at 37 degrees C but not those grown at 18 degrees C possessed hydrophobic adsorptive characteristics in addition to the property of mannose-resistant hemagglutination of guinea pig erythrocytes . Adsorption of K88-positive strains to gels with hydrophobic ligands was independent of O group and enterotoxicity . Strains lacking K88 antigen did not adsorb to the hydrophobically substituted derivatives of Sepharose and lacked mannose-resistant hemagglutinating characteristics . Neither the presence of additional polysaccharide K antigens nor nonhemagglutinating pili conferred the property of hydrophobic interaction on the strains . K88-positive bacteria had a lower electrophoretic migration rate than did K88-negative bacteria of the same serotype in free-zone electrophoresis . K88-positive bacteria also adsorbed strongly to hydrophobic ligands in the presence of 1 M ammonium sulfate, whereas K88-negative strains did not . These observations provide evidence for the suspected role of hydrophobic interaction in the adhesive properties of certain enteropathogenic strains of E . coli . Moreover, hydrophobic interaction chromatography provides convenient and rapid alternative means of screening strains for a property potentially associated with adhesiveness.

Infect Immun, 1978 Nov, 22(2), 312 - 7
Alterations in the tRNA's of Escherichia coli recovered from lethally infected animals; Griffiths E et al.; Escherichia coli grown in chemically defined iron-deficient media or in fluids containing the iron-binding proteins transferrin, lactoferrin, or ovotransferrin have well-characterized alterations in the chromatographic properties of tRNA's containing the modified nucleoside 2-methylthio-N6-(delta2-isopentenyl)-adenosine . The present work shows that similar tRNA alterations occur in E . coli O111 recovered from the peritoneal cavities of lethally infected guinea pigs and rabbits . Adding iron to these in vivo-grown bacteria resulted in the rapid conversion of chromatographically abnormal tRNA's to the normal species . The work strongly suggests that host iron-binding proteins, present in mucosal and other secretions, can affect the metabolism of invading organisms . The idea that the tRNA alterations are connected with the adaptation of E . coli to growth under the iron restricted conditions imposed by iron-binding proteins in tissue fluids, and thus with bacterial pathogenicity, is therefore made particularly attractive.

Biophys J, 1978 Nov, 24(2), 429 - 37
Relative rates of repair of single-strand breaks and postirradiation DNA degradation in normal and induced cells of Escherichia coli; Pollard EC et al.; Labeled DNA from irradiated Excherichia coli cells has been studied on an alkaline sucrose gradient without acid precipitation of the DNA . This enables the observation of both DNA repair and DNA degradation . The use of a predose of ultraviolet light (UV) causes induction of an inhibitor of postirradiation DNA degradation in lex+ strains . The effect of this induction on both the repair of single-strand breaks and DNA degradation has been followed in strains WU3610 (uvr+) and WU3610-89 (uvr-) . The repair process is more rapid than the degradation, and when degradation is inhibited more repair is apparent . Cells that are lex- (Bs-1 and AB2474) cannot be induced for inhibition of degradation . Nevertheless, by observation at short times repair can be seen clearly . This repaired DNA is degraded, suggesting that the signal for DNA degradation is not a single-strand break.

Appl Environ Microbiol, 1978 Nov, 36(5), 715 - 9
Dry-heat destruction of lipopolysaccharide: mathematical approach to process evaluation; Tsuji K et al.; A mathematical model was developed to estimate the number of logarithmic cycles (LDec) of lipopolysaccharide concentration destroyed by a dry-heat sterilization process . The LDec values calculated from the mathematical model agreed well with those obtained from the destruction of lipopolysaccharide by a dry-heat treatment . A discussion of how the mathematical model may be used to evaluate a dry-heat sterilization cycle is presented . This mathematical model and the dry-heat destruction curves indicated existence of a maximum LDec value at each temperature . The implications of this finding are discussed.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5636 - 9
Protein Ia and the lamB protein can replace each other in the constitution of an active receptor for the same coliphage; Wandersman C et al.; Protein Ia and the lamB protein are both located in the outer membrane of Escherichia coli K-12 . The lamB protein is known to be the receptor for phage lambda . Datta et al . {Datta, D . B., Arden, B . & Henning, U . (1977) J . Bacteriol . 131, 821--829} recently isolated a phage called TuIa that uses protein Ia for its adsorption . While phage TuIa fails to grow on ompB mutants, which lack protein Ia, we show here that host-range mutants of TuIa can be isolated that do grow on ompB strains . These host-range mutants fail to grow on ompB lamB double mutants, but retain the ability of the parental phage to grow on ompB+ lamB strains . They are therefore apparently able to use either protein Ia or the lamB protein for their adsorption . Genetic evidence suggests that essentially the same site on the lamB protein may be interacting with phage lambda or the host-range mutants of phage TuIa.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5627 - 30
Evidence for translocation of DNA sequences during sea urchin embryogenesis; Dickinson DG et al.; Hairpin-like DNA was prepared in vitro from the family of sequences that are inverted relative to each other and, as pairs, are relatively homologous and adjacent on the sea urchin genome . The majority of these hairpins are shown to have base pair mismatch positions distributed along their stems . Comparison of the hairpins derived from the DNA of morula, blastula, and gastrula stage embryos shows that during embryogenesis there are changes in the average number and position of S1 nuclease-sensitive base pair mismatch sites on the majority of the hairpin stems . Our data indicate that during early embryogenesis there are sequence changes in vivo within the majority of the adjacent inverted repeat sequences of the sea urchin genome . We have also found that there is higher specificity for the occurrence of sequence-change events within that fraction of the inverted repeat sequences that are methylated in vivo.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5417 - 21
Construction and characterization of a 2.5-kilobase procollagen clone; Lehrach H et al.; Recombinant bacterial plasmids have been constructed by inserting double-stranded chicken procollagen cDNA sequences linked to chemically synthesized decanucleotides containing HindIII sites into the HindIII site of pBR322 . After transformation of Escherichia coli chi1776, colonies were selected by ampicillin resistance and recombinants containing procollagen sequences were identified by colony hybridization to 32P-labeled procollagen cDNA . The inserts from three recombinant plasmids, pCg10, pCg13, and pCg45, were 1200, 2200, and 2550 base pairs long respectively . Their sequence homology has been established by restriction mapping and crosshybridization of nick-translated plasmids to Southern blots of Hpa II fragments of the inserts, pCg45 has been positively identified as containing the pro alpha2 collagen sequence by partial determination of the DNA sequence of its ends: it has a short thymine-rich sequence at one end and a sequence coding for residues 478--499 in the chicken alpha2 chain at the other end.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5381 - 5
Requirement of a plasmid-encoded protein for replication in vitro of plasmid R6K; Inuzuka M et al.; Conditions are described for the replication of exogeneous R6K DNA in an in vitro system prepared from Escherichia coli cells . Replication of plasmid DNA in this system is semiconservative and sensitive to actinomycin D, novobiocin, arabinofuranosyl-CTP,N-ethylmaleimide, and inhibitors of DNA-dependent RNA polymerase . An ammonium sulfate fraction prepared from cells carrying the R6K plasmid is required for replication . A direct role in replication for a plasmid-encoded protein, designated pi, in this fraction is indicated by the inactivity of this fraction when prepared from cells carrying a temperature-sensitive mutant plasmid and the thermolability of this fraction when prepared from cells carrying a partial revertant of the mutant plasmid . This plasmid-encoded protein is necessary for the initiation of R6K DNA replication and functions before or during the formation of nascent RNA in the initiation process . The results of titration assays of this protein using various template DNAs suggest that the protein interacts with the plasmid DNA at the region essential for DNA replication.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5367 - 71
Molecular analysis of cloned human 18S ribosomal DNA segments; Wilson GN et al.; A fraction of DNA from the human fetal lung fibroblast line IMR-90, 30-fold enriched for ribosomal DNA, was cloned in the lambda phage vector Charon 16A . Of 978 clones assayed by hybridization to a mixture of 125I-labeled 18S and 28S ribosomal RNA, 11 recombinants containing a 3.8-megadalton segment of human 18S ribosomal DNA were identified . Restriction endonuclease analysis of these clones demonstrated variation only in orientation of the human gene segment within the phage vector . Restriction sites that we had previously detected from analysis of restriction products of unfractionated human DNA by using the Southern transfer method were also present in the cloned DNA segment . Recombinant DNA technology thus provides a valid and efficient means to define structural conservation or variation within families of human genes.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5349 - 52
Oxidation of the methionine residues of Escherichia coli ribosomal protein L12 decreases the protein's biological activity; Caldwell P et al.; Oxidation of ribosomal protein L12 with hydrogen peroxide converts the three methionine residues to methionine sulfoxide . The oxidized protein has a decreased ability to bind to ribosomes, interact with ribosomal protein L10, be precipitated by L12 antiserum, and serve as substrate for the acetylating enzyme that converts L12 to L7 . Full activity of L12 is regained when the protein is reduced with 2-mercaptoethanol . Sedimentation equilibrium analysis shows that oxidation of the methionine residues in L12 causes the conversion of the protein from the dimer to the monomer form, and the results indicate that the dimer is the active form of the protein in the above reactions.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5314 - 8
Contacts between Escherichia coli RNA polymerase and a lac operon promoter; Johnsrud L; The chemical alkylating agent dimethyl sulfate can probe the interaction between Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) and the purine bases of a promoter . This agent methylates the N7 position on guanine or the N3 position on adenine; the bound protein can either protect these positions or affect the reactivity to produce an enhanced methylation . The pattern of DNA residues in the lactose promoter protected from, or enhanced to, methylation by a specifically bound polymerase shows that the enzyme covers a region of at least 38 base pairs, stretching upstream from the origin of transcription . These protein-DNA contacts occur predominantly in the major groove of the DNA helix . Furthermore, this pattern of methylation shows that the polymerase unwinds the helix at the origin of transcription . The relationship between polymerase-DNA contacts defined by dimethyl sulfate and known features of promoter structure is discussed . To facilitate these experiments I have constructed a plasmid that permits a unique 5'-end labeling of each strand of a 95-base-pair fragment containing a lac operon promoter . This plasmid contains two copies of the lac promoter-operator region.

Proc Natl Acad Sci U S A, 1978 Nov, 75(11), 5276 - 80
Three-dimensional structures of aspartate carbamoyltransferase from Escherichia coli and of its complex with cytidine triphosphate; Monaco HL et al.; X-ray diffraction studies to nominal resolutions of 3.0 A for unliganded aspartate carbamolytransferase (EC 2.1.3.2)(R32 crystal symmetry) and of 2.8 A for the complex of aspartate carbamoyltransferase with cytidine triphosphate (P321 crystal symmetry) have yielded traces of the polypeptide chains of the catalytic (C) and regulatory (R) chains in the hexameric C6R6 molecules . The independent molecular structures of the liganded and unliganded forms of the enzyme are very nearly identical . In the regulatory chain there is a CTP-binding domain that interacts with an adjacent regulatory subunit and a zinc-binding domain that interacts with the catalytic subunit . In the catalytic chain a polar domain shows interactions between adjacent pairs of C chains to form each trimer C3 while an equatorial domain shows intramolecular C3--C3 interactions . The active site is at or near the interface between adjacent C chains within the trimers . Probably each active center involves amino acid residues from adjacent C chains.

Nucleic Acids Res, 1978 Nov, 5(11), 4305 - 15
Separation of ribosomal subunits of Escherichia coli by Sepharose chromatography using reverse salt gradient; Kirillov SV et al.; A mixture of 30 S and 50 S subunits quantitatively absorbs on a column of Sepharose--4B from the buffer: 0.02 M Tris--HCl, pH 7.5, containing 1.5 M (NH4)2SO4 . During elution by reverse gradient of ammonium sulphate (1.5--0.05 M) the subunits are eluted at different salt concentrations . Complete separation of subunits is attained in the absence of Mg2+ ions . The 30 S subunits prepared from 70 S ribosomes according to this procedure are fully active in the codon--dependent binding of a specific aminoacyl--tRNA . After their reassociation with 50 S subunits isolated by zonal centrifugation, the resulting 70 S ribosomes are active in polypeptide synthesis at the same degree as control 70 S ribosomes in which both types of subunits were prepared by zonal centrifugation . The initial 70 S ribosomes for the chromatographic separation into subunits can be obtained by their pelleting from a crude extract with subsequent washing with concentrated solutions of NH4Cl in the ultracentrifuge, or by salt fractionation of the crude extract according to a slightly modified procedure of Kurland.

Nucleic Acids Res, 1978 Nov, 5(11), 4245 - 61
T7 gene 6 exonuclease has an RNase H activity; Shinozaki K et al.; T7 gene 6 exonuclease has been shown to have an RNase H activity as well as a double-strand specific DNase activity by the following experiments: The RNase H activity coelutes with the DNase activity from DEAE-cellulose, phosphocellulose, hydroxyapatite, and Sephadex G-200 columns . Gene 6 exonuclease specified by a T7 strain with a temperature sensitive mutation in gene 6 has an extremely heat-labile RNase H activity as well as a heat-labile DNase activity . T7 gene 6 exonuclease degrades the RNA region of a poly(A) . poly(dT) hybrid polymer exonucleolytically from the 5' terminus, releasing a ribonucleoside 5'-monophosphate product . When the RNA strand of a 0X174 RNA . DNA hybrid molecule synthesized with E . coli RNA polymerase is degraded, a ribonucleoside triphosphate is produced from the 5'-triphosphate terminus . Participation of T7 gene 6 exonuclease in the removal of primer RNA in discontinuous replication of T7 DNA is discussed.

Nord Vet Med, 1978 Nov, 30(11), 486 - 8
Neonatal infections in puppies caused by Escherichia coli serogroups 04 and 025; Askaa J et al.; Three cases of neonatal E . coli infection in Newfoundland dogs are described . The serological examination showed that the implicated E . coli belonged to sero-group 04 in two outbreaks while sero-group 025 was responsible for one outbreak . In one of the kennels with implication of 04, this 0-group was also isolated from adult dogs with diarrheal conditions.

J Med Microbiol, 1978 Nov, 11(4), 493 - 9
Passive protection of lambs against experimental enteric colibacillosis by colostral transfer of antibodies from K99-vaccinated ewes; Sojka WJ et al.; Pregnant ewes were vaccinated with partially purified, cell-free K99 antigen isolated from an enteropathogenic strain of Escherichia coli, strain B41 (O101:K99:NM), to induce passive immunity via the colostrum in their offspring against an oral challenge with heterologous "calf-lamb" enteropathogenic strains of E . coli B44 . After sucking their dams, lambs were dosed orally with 7X10(10)-2.2 X10(11) organisms within 4--21 h of birth . One group of 10 lambs was dosed with cultures of the mucoid (O9:K30(A),K99:NM) form of strain B44 and another group of 10 lambs with the non-mucoid (O9:K99:NM) form; two groups of four control lambs from unvaccinated dams were similarly challenged . All four control lambs challenged with mucoid B44, loose feaces were detected in only two of the four control lambs and in none of the lambs from vaccinated dams . This suggests that the polysaccharide K antigen may contribute to the virulence of "calf-lamb" enteropathogenic strains that possess the K99 antigen . However, lambs passively immunised with colostrum from dams vaccinated with K99 antigen alone were protected against the production of enteric colibacillosis by oral challenge with EPEC strain B44.

J Dent Res, 1978 Nov-Dec, 57(11-12), 1003 - 15
Microscopic assay for the phagocytotic-collagenolytic performance (PCP index) of human gingival fibroblasts in vitro; Rose GG et al.; Using 16 human gingival fibroblasts cell lines from patients with periodontitis, Dilantin hyperplasia, and nonpathological gingiva, a microscopic assay was developed to quantitate the cells' ability to lyse collagen substrates . The method employs tissue culture chambers with one cover slip partially coated with a thin layer of undenatured fibrillar bovine collagen . The assay measures the relative numbers and sizes of holes in the collagen within defined regions of the cover slips effected by the phagocytotoc and collagenolytic performance (PCP) of the population of fibroblasts growing on the cover slip for 5 days . The effect on the PCP index by serum, heparin, prostaglandins, and endotoxin was evaluated.

J Antibiot (Tokyo), 1978 Nov, 31(11), 1137 - 42
Streptothricin F, an inhibitor of protein synthesis with miscoding activity; Haupt I et al.; The effect of streptothricin F on macromolecular syntheses in intact cells and cell-free protein synthesis of E . coli was studied . The results indicate that protein synthesis is the primary site of inhibition by streptothricin F in growing E . coli cells . Cell-free polypeptide synthesis from E . coli directed by poly (U) was inhibited, while poly (A) and poly (C) directed polypeptide syntheses were both stimulated by the drug . Furthermore, streptothricin F caused misreading of translation of poly (U), poly (A) and poly (C) directed protein syntheses in E . coli systems . The extent of misreading by streptothricin F increases with increasing drug concentrations . The results are compared with those of other miscoding antibiotics . In rat liver extracts protein directed by poly (U) or endogenous mRNA was not inhibited.

Genetika, 1978 Nov, 14(11), 1876 - 83
{Effect of B polA1- exrA- and recA-gene mutations on the reparation of single-strand DNA breaks induced by N-nitrosomethylurea}; Davnichenko LS et al.; The effect of different doses of N-methyl-N-nitrosourea (MNU) on a viability of bacterial cells with different defects in the systems of repair of UV-damages, and the MNU induction of single-strand DNA breaks (SS) were studied . The kinetics of both processes was investigated . There was a good correlation between the NMU sensitivity of bacterial cells and the number of SS in their DNAs . The most sensitive were the cells defective in DNA polymerase I . The optimal conditions for DNA repair in the strains under investigation were established . 90% of MNU-induced SS are repaired by DNA polymerase I and do not depend on protein synthesis . On the other hand, the exrA and recA dependent ways of SS repair depend on protein synthesis . The existence of an inducible recAexrA-dependent repair system of NMU-induced lesions in bacterial DNA is proposed.

Acta Paediatr Scand, 1978 Nov, 67(6), 769 - 73
Longterm follow-up of neonatal septicemia; Alfven G et al.; The longterm prognosis of neonatal septicemia during the first four weeks of life has been estimated . Of 90 infants with the diagnosis of neonatal septicemia during a five-year period, 1969--1973, 65 infants survived the initial treatment . Another two infants died with complications of their main disease, intestinal atresia, at the age of two months . Thus the total mortality in neonatal septicemia in this series was 30% . The remaining 63 children have been investigated between ages of 2 1/2 and 6 1/2 years . Of these 63 children we have found 14 children (22% of the surviving) with handicaps where the septicemia can be regarded as a possible cause of the handicap . Of these 14 children only six had an "uncomplicated" septicemia while four of them had meningitis and four had osteomyelitis . Furthermore, of the 14 handicapped children nine were delivered preterm (28--36 weeks) and all of them had one or more additional neonatal diagnoses than septicemia . The prognosis, both immediate and longterm, of neonatal septicemia in the present series compares favourably to most international studies . The importance of early detection together with an aggresive treatment of the septicemia is stressed and is considered as the main reason for the good prognosis.

Surgery, 1978 Nov, 84(5), 588 - 94
Protein and fat utilization in shock; Daniel AM et al.; A previous study demonstrated that in the dog, shock, regardless of its etiology, resulted in increased oxidative utilization of substrates which form lactate and pyruvate as intermediary metabolites . The study implied a concomitant decrease in free fatty acid oxidation, as the oxidative pathway of the latter does not involve the lactate-pyruvate step . To test this hypothesis, free fatty acid metabolism was investigated by infusing carbon-14 labelled fatty acid in 12 normal dogs, in nine animals in shock due to controlled cardiac tamponade, and in six animals with endotoxin shock . The shock state was characterized by significant (p less than 0.05) decrease both in arterial fatty acid concentration and in free fatty acid turnover . In addition, both the rate of free fatty acid oxidation and the percentage of the total CO2 derived from free fatty acid oxidation were significantly (p less than 0.05) diminished . In contrast, urea production rates were higher in shock, and the calculated maximum contribution of protein oxidation to total CO2 production rose from 23% in the control animals to 50% in the test groups.

J Bacteriol, 1978 Nov, 136(2), 825 - 7
Orotic acid excretion in some wild-type strains of Escherichia coli K-12; Womack JE et al.; During rapid growth, the excretion of pyrimidines, predominantly uracil, is a common phenomenon in procaryotes and eucaryotes . In Escherichia coli, some K-12 strains excrete orotic acid and not uracil . This is caused by a mutation in the pyrF gene.

J Bacteriol, 1978 Nov, 136(2), 723 - 9
Arrangement of glycan chains in the sacculus of Escherichia coli; Verwer RW et al.; A novel of Escherichia coli endopeptidase was used for a selective partial hydrolysis of the peptide bridges which interlink the glycan chains in E . coli sacculi . The loosening of the murein network revealed, in the electron microscope, a preferential orientation of the glycan chains, more or less perpendicular to the length axis of the cell . Control incubations with E . coli transglycosylase or egg-white lysozyme did not leave ordered structures behind.

J Bacteriol, 1978 Nov, 136(2), 631 - 7
Cell division during nutritional upshifts of Escherichia coli; Loeb A et al.; Nutritional shifts of Escherichia coli B/r to richer media have been analyzed is synchronously growing and exponential-hase populations . Early perturbations in the timing of cell division were observed . At the slow growth, division progressed at a rate equal to or less than the preshift rate for about 1 h . At intermediate growth, both delays and acceleration in division were observed . The extent of the perturbation depended upon the age of the cells at the time of the shift and the composition of the preshift and postshift media . The perturbation was different in the two substrains of E . coli B/r used in this study.

J Bacteriol, 1978 Nov, 136(2), 538 - 47
Repair of cross-linked DNA and survival of Escherichia coli treated with psoralen and light: effects of mutations influencing genetic recombination and DNA metabolism; Sinden RR et al.; Repair of cross-linked DNA was studied in Escherichia coli strains carrying mutations affecting DNA metabolism . In wild-type cells, DNA strands cut during cross-link removal were rejoined during a subsequent incubation into high-molecular-weight molecules . This rejoining was dependent on gene products involved in genetic recombination . A close correlation was found relating recombination proficiency, the rate of strand rejoining, and formation of viable progeny after DNA cross-linking by treatment with psoralen and light . Wild-type cells and other mutants which were Rec+ (sbcB, recL, recL sbcB, recB recC sbcA, recB recC sbcB, xthA1, and xthA11) rejoined cut DNA strands at a rate of 0.8 +/- 0.1 min -1 at 37 degrees C and survived 53 to 71 cross-links per chromosome . recB, recC, recB recC, recF, or polA strains showed reduced rates of strand rejoining and survived 4 to 13 cross-links per chromosome . Recombination-deficient strains (recA, recB recC sbcB recF, recB recL) and lexA failed to rejoin DNA strands after crosslink removal and were unable to form colonies after treatments producing as few as one to two cross-links per chromosome . Strand rejoining occurred normally in cells with mutations affecting DNA replication (dnaA, danB, dnaG, and dnaE) under both permissive and nonpermissive conditions for chromosome replication . In a polA polB dnaE strain strand rejoining occurred at 32 degree C but not at 42 degree C, indicating that some DNA synthesis was required for formation of intact recombinant molecules.

J Bacteriol, 1978 Nov, 136(2), 501 - 6
Chromosomal location of a gene (nmpA) involved in expression of a major outer membrane protein in Escherichia coli; Foulds J et al.; The phenotypic expression of protein E, a recently described major outer membrane protein, is associated with a mutation at a locus on the Escherichia coli chromosome that we call nmpA . nmpA is located between rbsK and uncA at 82.7 min on the E . coli linkage map . The nmpA locus is also the site of the mutations which lead to the formation of major outer membrane proteins Ic or e . It is likely proteins E, Ic, and e are closely related or identical . The mutant nmpA allele is dominant.

J Bacteriol, 1978 Nov, 136(2), 477 - 83
Stimulation of deletions in the Escherichia coli chromosome by partially induced Mucts62 prophages; Faelen M et al.; Deletion of bacterial DNA fragments is stimulated in induced Mucts62 lysogens . The host genes located proximally to the prophage are more frequently lost than those which are unlinked to the Mu genome . Genes located on either side of a Mu genome are deleted in the same manner . Like the other Mu-induced rearrangements, this process is recA independent and requires the participation of Mu DNA, as indicated by the fact that a phage genome always replaces the deleted genes . Data are presented which strongly suggest that both ends of the Mu genome are involved in deletion formation.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Nov, 34(5), 411 - 5
Suppression of induced beta-galactosidase synthesis by cysteamine and its reversion by gamma-irradiation in the presence of ascorbate; Naslund M et al.; The induced synthesis of beta-galactosidase in E . coli was found to be inhibited by cysteamine . This inhibitory effect of the SH compound was antagonized by the addition of ascorbate followed by gamma-irradiation with relatively low doses . The cAMP level which, it has been suggested, plays a role in the radioprotective action of cysteamine, is stabilized by ascorbate against changes induced by irradiation.

Can J Microbiol, 1978 Nov, 24(11), 1423 - 5
Construction of an Escherichia coli strain which excretes abnormally large amounts of adenosine 3',5'-cyclic monophosphate; Fraser DE et al.; It has previously been shown that an Escherichia coli CRP- strain 5333 accumulates abnormally large amounts of adenosine 3',5'-cyclic monophosphate (cAMP) . Using P1 transduction, the CRP- character was transferred to E . coli Crookes strain which is deficient for cAMP phophodiesterase (CPD-) . The resulting strain HY22 (CRP-, CPD-) accumulates greater amounts of cAMP both intracellularly and extracellularly than does 5333 . In glucose minimal medium, an HY22 cell accumulates 100 times more cAMP intracellularly and excretes cAMP 150 times faster than does a wild-type E . coli cell.

Biochem J, 1978 Nov 1, 175(2), 495 - 9
Activation of nitrite reductase from Escherichia coli K12 by oxidized nicotinamide-adenine dinucleotide; Coleman KJ et al.; Nitrite reductase from Escherichia coli K12 requires the presence of NAD+, one of the products of the reduction of NO2-by NADH, for full activity . The effect is observed with both crude extracts and purified enzyme . NAD+ also acts as a product inhibitor at high concentrations, and plots of initial rate against NAD+ concentration are bell-shaped . The maximum occurs at about 1 mM-NAD+, but increases with increasing NADH concentration . In the presence of 1 mM-NAD+ and saturating NO2-(2mM) the Michaelis constant for NADH is about 16 micron . The Michaelis constant for NO2-is about 5 micron and is largely independent of the NAD+ concentration . Similar but more pronounced effects of NAD+ are observed with hydroxylamine as electron acceptor instead of NO2- . The maximum rate of NADH oxidation by hydroxylamine is about 5.4 times greater than the maximum rate of NADH oxidation by NO2- when assayed with the same volume of the same preparation of purified enzyme . The Michaelis constant for hydroxylamine is 5.3 mM, however, about 1000 times higher than for NO2- . These results are consistent with a mechanism in which the same enzyme-hydroxylamine complex occurs as an intermediate in both reactions.

Biochem J, 1978 Nov 1, 175(2), 483 - 93
Purification and properties of nitrite reductase from Escherichia coli K12; Coleman KJ et al.; NADH-nitrite oxidoreductase (EC 1.6.4) was purified to better than 95% homogeneity from batch cultures of Escherichia coli strain OR75Ch15, which is partially constitutive for nitrite reductase synthesis . Yields of purified enzyme were low, mainly because of a large loss of activity during chromatography on DEAE-cellulose . The quantitative separation of cytochrome c-552 from nitrite reductase activity resulted in an increase in the specific activity of the enzyme: this cytochrome is not therefore an integral part of nitrite reductase . The subunit molecular weights of nitrite reductase and of a haemoprotein contaminant, as determined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, were 88000 and 80000 respectively . The sedimentation coefficient was calculated to be in the range 8.5-9.5S, consistent with a mol.wt . of 190000 . It is suggested therefore that the native enzyme is a dimer with two identical or similar-sized subunits . Purest samples contained 0.4 mol of flavin/mol of enzyme, but no detectable haem . Catalytic activity was totally inhibited by 20 micron-p-chloromercuribenzoate and 1 mM-cyanide, slightly inhibited by 1 micron-sulphite and 10mM-arsenite, but insensitive to 1 mM-2,2'-bipyridine, 4mM-1,10-phenanthroline and 10mM-NaN3 . Three molecules of NADH were oxidized for each NO2-ion reduced: the product of the reaction is therefore assumed to be NH4+ . The specific activity of hydroxylamine reductase increased at each step in the purification of nitrite reductase, and the elution profiles for these two activities during chromatography on DEAE-Sephadex were coincident . It is likely that a single enzyme is responsible for both activities.

J Bacteriol, 1978 Nov, 136(2), 812 - 4
Changes in composition of envelope proteins in adenylate cyclase- or cyclic AMP receptor protein-deficient mutants of Escherichia coli; Aono R et al.; Synthesis of several envelope proteins in Escherichia coli K-12 is regulated by cyclic AMP and cyclic AMP receptor protein.

Z Naturforsch {C}, 1978 Nov-Dec, 33(11-12), 1006 - 8
Uracil catabolism by Escherichia coli K12S; Simaga S et al.; Experiments designed to elucidate the mechanism of uracil degradation by E . coli K12S showed that in contrast to uracil, dihydrouracil--the postulated intermediate of a reductive mechanism--did not stimulate the growth of bacteria as additional source of nitrogen, nor it was catabolized to ureido carbon dioxide . However, the chromatographic analysis of dihydrouracil metabolic products, revealed the presence of an enzyme converting dihydrouracil to beta-ureidopropionic acid . Results of growth and biochemical studies indicated that barbituric acid--the postulated intermediate of an oxidative pathway--is not involved in uracil degradation.

J Bacteriol, 1978 Nov, 136(2), 570 - 81
Method for isolation of Escherichia coli mutants with defects in the proton-translocating sector of the membrane adenosine triphosphatase complex; Fillingame RH et al.; A technique for selecting mutants of Escherichia coli in which the proton-translocating sector of the adenosine triphosphatase (ATPase) complex has been inactivated is reported . The procedure uses a strain of E . coli (NR-70) lacking the extrinsic (F1) sector of the ATPase complex and which in consequently permeable to protons (B . P . Rosen, J . Bacteriol . 116:1124--1129, 1973) . After growing strain NR-70 under noninducing conditions for the lac operon, cells were mutagenized and plated on minimal medium containing low concentrations of lactose . Several mutants of strain NR-70 were isolated as large colonies on these plates, apparently because they could concentrate lactose more efficiently . A description of one of the mutants, strain KW-1, is reported here . The most distinguishing difference in growth properties of the two strains was that, when transferred to medium containing low concentrations of lactose, strain KW-1 induced the lac operon with a shorter lag time than strain NR-70 . The mutation in strain KW-1 leading to more rapid growth on lactose was cotransducible with the asn and unc loci, at 83 min on the E . coli genetic map . Intact cells of strain KW-1 actively transported L-proline as well as did wild-type cells, whereas cells of strain NR-70 were markedly deficient in L-proline transport . The improvement in the transport capacity of strain KW-1 correlated with a marked decrease in proton permeability relative to that of strain NR-70 . Based on an acid-base pulse technique that measured the proton conductance of the membranes of intact cells, strain NR-70 was at least 10 times more permeable to protons than was the wild type, whereas strain KW-1 was only 2 times more permeable . The transport properties and proton conductance were also compared with membrane vesicles prepared by osmotic shock . With either D-lactate or ascorbate-N-methylphenazonium methosulfate as respiratory substrates, vesicles of strain KW-1 transported L-proline much more rapidly than did vesicles of strain NR-70, but still at rates less rapid than those of the wild type . The passive proton conductance of the membrane vesicles was quantitated by measuring the rate of H+ influx into vesicles in response to a valinomycin-generated K+ diffusion potential . The proton permeability of vesicles of strain KW-1 was reduced 1.5-fold relative to vesicles of strain NR-70, but these vesicles were still four times more permeable to protons than was the wild type . Vesicles of strain KW-1 corresponded to wild-type vesicles treated with 0.5 micrometer carbonylcyanide m-chlorophenylhydrazone (CCCP) and vesicles of strain NR-70 corresponded to wild-type vesicles treated with 1.4 micrometer CCCP . Treatment of wild-type vesicles with these concentrations of CCCP caused decreases in transport comparable to those observed in the mutants . Strain KW-1 lacked ATPase activity . Cross-reacting material to F1-ATPase was not found in strain KW-1 by double immunodiffusion analysis.

J Clin Endocrinol Metab, 1978 Nov, 47(5), 980 - 4
Enzyme immunoassay of human chorionic gonadotropin employing beta-galactosidase as label; Kikutani M et al.; An enzyme-linked immunoassay was applied to the determination of hCG, a glycoprotein hormone usually assayed by RIA . For this purpose, an enzyme hormone conjugate was prepared by reacting hCG with beta-D-galactosidase (beta-Gal.) of E . coli in the presence of N-(m-maleimidobenzoyloxy) succinimide (MBS) as coupling reagent . The conjugate, after purification by affinity and gel chromatographies, was shown to exhibit sufficient enzyme activity and immunoactivity . The immunoassay of hCG was performed by the double antibody method and, using this assay, 0.4-250 mIU/ml hCG were detectable . This was about 10 times as sensitive as the RIA . Difficulty was experienced when this method was utilized for the determination of hCG in plasma samples from patients . Since the presence of the plasma may have affected this assay method, the following improvements were made: 1) the same volume of hormone-free plasma was added to the standard solutions of hCG, and 2) the volume of plasma sample was 10 microliter . The performance and validity of this assay were comparable to the RIA using {125I}hCG as tracer . The dose-response curves of both assay have the same slope and there was no significant difference between the values (correlation coefficient, Y = 0.96X + 1.53).

Biochem J, 1978 Nov 1, 175(2), 539 - 46
The necessity of magnesium cation for acid assistance aglycone departure in catalysis by Escherichia coli (lacZ) beta-galactosidase; Sinnott ML et al.; 1 . Removal of Mg2+ from Escherichia coli (lacZ) beta-galactosidase slightly increases the rate of hydrolysis of galactosyl pyridinium salts, but decreases the rate of hydrolysis of arylgalactosides . 2 . Fair correlation of logkcat . and log (Km) with the pKa of aglycone is now observed for arglygalactosides, as well as for glycosyl pyridinium salts . 3 . Degalactosylation of Mg2+-free enzyme is the rate-limiting step in the hydrolysis of 2,4-dinitrophenyl galactoside . 4 . alpha-Deuterium kinetic isotope effects for both sets of substrates are consistent with the rate-determining generation of a glycosyl cation . 5 . The pH-independent, SNl hydrolysis of 3,4-dinitrophenyl galactoside has been measured: it is as fast as that of the galactosyl 3-chloropyridinium ion . 6 . Hydrolysis of these two substrates by Mg2+-free enzyme proceeds at very similar rates . 7 . It is concluded that loss of both types of aglycone takes place, without acid catalysis, from the first ES complex of substrate and apoenzyme . 8 . Data for galactosyl azide and thiopicrate confirm that neither charge nor change of atom is the cause of the differences in behavior between aryl galactosides and galactosylpyridinium salts.

Biochem J, 1978 Nov 1, 175(2), 525 - 38
Affinity labelling with a deaminatively generated carbonium ion . Kinetics and stoicheiometry of the alkylation of methionine-500 of the lacZ beta-galactosidase of Escherichia coli by beta-D-galactopyranosylmethyl-p-nitrophenyltriazene; Sinnott ML et al.; 1 . beta-D-Galactopyranosylmethyl-p-nitrophenyltriazene is an active-site-directed irreversible inhibitor of Mg2+-bound and Mg2+-free lacZ beta-galactosidase from Escherichia coli . 2 . The Mg2+-enzyme binds the inhibitor more tightly but the complex then decomposes less rapidly than is the case with Mg2+-free enzyme . 3 . Loss of enzyme activity is a linear function of the fraction of enzyme protomers to which are attached beta-D-galactopranosyl{14C}methyl residues: complete inactivation of fully active enzyme results in incorporation of 0.91 equivalent of carbohydrate label per enzyme protomer . 4 . When the beta-galactopyranosylmethyl cation is generated in the active site of Mg2+-enzyme, it is captured essentially completely by the protein, but in the active site of Mg2+-free enzyme it is only captured with an efficiency of 25% . 5 . Labelled enzyme was carboxymethylated and digested with trypsin; acidic hydrolysis of the isolated tryptic peptide, and field-desorption mass spectrometry of the isolated radioactive derivative, showed it to be 2,5-dioxo-3{2-(beta-D-galactopyranosylmethylthio)ethyl}-1,6-trimethylenepiperazine . 6 . This is considered to have arisen from labelling of the sulphur atom of a methionine residue adjacent to a proline residue . 7 . The complete amino acid sequence of the molecule {Fowler & Zabin (1977) Proc . Natl . Acad . Sci . U.S.A . 74, 1507-1510} enables the labelled methionine residue to be identified as either Met-421 or Met-500 . 8 . Sequence data {Fowler, Zabin, Sinnott & Smith (1978) J . Biol . Chem . in the press} show the site of attack to be Met-500.

Zentralbl Bakteriol {B}, 1978 Nov, 167(4), 362 - 74
{Hygienic analyses carried out in a public sauna (author's transl)}; Graf W et al.; In a public sauna a considerable germ level was found to exist in all areas during rush hours . Although no specifically pathogenic germs were detected on the surfaces, the existence of E . coli would suggest that particular attention must be given to the hygiene of this type of bathing establishment . It is particularly important that the relatively high temperatures in the heated area of the sauna do not cause a hygienically decisive germ reduction . Apart from this, especially the foot-warming basins appear to be undesirable germ reservoirs, even for pathogenic germs (Staph, aureus, P . aeruginosa) . Systematic daily disinfection, which is recommended as a basic requirement but which in practice is mostly omitted, proves indispensable . Proper use of the relatively harmless hydrogen peroxide allows the hygienic conditions to be clearly improved, shortly.

J Biochem (Tokyo), 1978 Nov, 84(5), 1285 - 90
Induced synthesis of immunoglobulin messenger RNA accompanies induction of immunoglobulin production in cultured mouse spleen cells; Tsuda M et al.; Immunoglobulin kappa type light chain mRNA (Lkappa mRNA) accumulated in parallel with secretion of immunoglobulin M in cultured mouse spleen cells activated by lipopolysaccharide . Actinomycin D suppressed the accumulation of kappa chain mRNA completely without affecting the degradation rate of kappa chain mRNA . The half life of kappa chain mRNA was about 9 h . Available evidence indicates that lipopolysaccharide stimulates de novo synthesis of kappa chain mRNA . The accumulation of kappa chain mRNA was markedly suppressed by inhibitors of DNA or protein synthesis such as hydroxyurea, cytosine arabinoside and cycloheximide.

J Immunol, 1978 Nov, 121(5), 1664 - 70
Macrophage sensitivity to endotoxin: genetic control by a single codominant gene; Rosenstreich DL et al.; The effects of LPS on macrophages in vitro have been examined . LPS triggers macrophages to produce LAF and PGE2 in vitro . LPS is also cytotoxic for macrophages derived from LPS-sensitive mice and will significantly inhibit their phagocytic ability . Both LAF production and cytotoxicity are due to the direct effects of LPS on the macrophage and do not require the particpation of lymphocytes . Each of these functions is abnormal in C3H/HeJ mice . The nature of the gene(s) controlling these macrophage responses to LPS has been determined . The response of (C3H/HeJ X C3H/HeN)F1 macrophages was intermediate when compared to the parental responses and no sex linkage was found . Backcross linkage analysis suggested that the same autosomal codominant gene controls both macrophage and B lymphocyte-LPS sensitivity.

J Microsc, 1978 Nov, 114(2), 229 - 39
Negative staining of freeze-fractured envelopes of Escherichia coli K12; Nermut MV et al.; Envelope fragments of E . coli K12 have been produced by freeze-fracturing "by hand" and negatively stained after thawing . The outer leaflet of the plasma membrane disintegrated upon thawing whereas the outer leaflet of the outer membrane did not . Negative staining revealed the following structural features on the outer membrane fragments: (i) "grooves" 4-6 nm wide, (ii) spherical particles 6-8 nm in diameter, (iii) "black dots" 3-8 nm in diameter . Treatment of cells with EDTA before freeze-fracturing caused dilation of grooves into holes eventually leading to fragmentation of the outer membrane . A mutant strain deficient in two outer membrane proteins fractured exclusively through the outer membrane . The outer leaflets so obtained disintegrated upon thawing similarly as observed for the outer leaflet of the plasma membrane.

Infect Immun, 1978 Nov, 22(2), 555 - 9
K99 surface antigen of Escherichia coli: antigenic characterization; Isaacson RE; K99 prepared by acid precipitation hemagglutinated guinea pig erythrocytes, whereas K99 prepared by chromatography on diethylaminoethyl-Sephadex did not . K99 purified by either procedure hemagglutinated horse erythrocytes . K99 prepared by acid precipitation contained a second antigen not presnet in the K99 prepared by chromatography on diethylaminoethyl-Sephadex . This antigen could be detected by immunoprecipitation with some, but not all, sera prepared against K99-positive Escherichia coli strains . It was assumed that this second antigen is not K99 and is responsible for the guinea pig erythrocyte hemagglutination reaction . Furthermore, the second antigen has an isoelectric point of 4.2, which has been reported by Morris and co-workers to be the isoelectric point of K99.

Gene, 1978 Nov, 4(3), 195 - 212
EcoRI activity: enzyme modification or activation of accompanying endonuclease?
Tikchonenko TI, Karamov EV, Zavizion BA, Naroditsky BS.
A study has been made of the factors and mechanism leading to appearance of the so-called EcoRI activity described by Polisky et al . (1975) in the restrictase EcoRI preparations . The preparations of purified restrictase EcoRI, precipitated at 0.9 ammonium sulphate saturation, as well as that obtained using standard techniques have been found to contain an admixture of an endonuclease which at neutral pH and high ionic strength multiply cleaves those DNAs which normally have only one recognition site for EcoRI . Under the standard conditions for EcoRI digestion this activity is found only when large amounts of freshly isolated enzyme are added to the incubation mixture and it is sharply enhanced by replacement of Mg2+ with Mn2+ . The number and size of DNA fragments produced under such conditions practically do not differ from those found under the so-called EcoRI conditions, that is for alkaline pH values and low ionic strength . The optimum incubation mixture for the EcoRI activity has been found to be 10 mM Tris . HCl buffer (pH 8.8) + 2 mM Mn2+ . Similar activity is induced also by addition to EcoRI solution of 40--50% glycerol or a number of organic solvents (dimethylacetamide (DMA), dimethylformamide (DMF), dimethylsulphoxide (DMSO), sulphalane (SP) in concentrations from 1 to 6% . The EcoRI activity induced by 50% glycerol or at alkaline pH values and low ionic strength is suppressed or sharply inhibited by 2--3 mM parachloromercuribenzoate (PCMB), while EcoRI is not sensitive to this agent . The DNA fragments cleaved by EcoRI have cohesive termini and can be easily ligated . It is suggested that the EcoRI activity can be due not only (or largely not) to modification of the "recognizing capacity" of the EcoRI restrictase but not activation of a latent specific endonuclease which is present in the restrictase preparation as an impurity.

J Bacteriol, 1978 Nov, 136(2), 657 - 67
Presence of Escherichia coli of a deaminase and a reductase involved in biosynthesis of riboflavin; Burrows RB et al.; Two enzymes have been partially purified from extracts of Escherchia coli B which together catalyze the conversion of the product of the action of GTP cyclohydrolase II, 2,5-diamino-6-oxy-4-(5'-phosphoribosylamine)pyrimidine, to 5-amino-2,6-dioxy-4-(5'-phosphoribitylamine)pyrimidine . These two compounds are currently thought to be intermediates in the biosynthesis of riboflavin . The enzymatic conversion occurs in two steps . The product of the action of GTP cyclohydrolase II first undergoes hydrolytic deamination at carbon 2 of the ring, followed by reduction of the ribosylamino group to a ribitylamino group . The enzyme which catalyzes the first step, herein called the "deaminase," has been purified 200-fold . The activity was assayed by detecting the conversion of the product of the reaction catalyzed by GTP cyclohydrolase II to a compound which reacts with butanedione to form 6,7-dimethyllumazine . The enzyme has a molecular weight of approximately 80,000 and a pH optimum of 9.1 . The dephosphorylated form of the substrate is not deaminated in the presence of the enzyme . The assay for the enzyme which catalyzes the second step, referred to here as the "reductase," involves the detection of the conversion of the product of the deaminase-catalyzed reaction to a compound which, after treatment with alkaline phosphatase, reacts with butanedione to form 6,7-dimethyl-8-ribityllumazine . The reductase has a molecular weight of approximately 40,000 and a pH optimum of 7.5 . Like the deaminase, the reductase does not act on the dephosphorylated form of its substrate . Reduced nicotinamide adenine dinucleotide phosphate is required as a cofactor; reduced nicotinamide adenine dinucleotide can be used about 30% as well as the phosphate form . The activity of neither enzyme is inhibited by riboflavin, FMN, or flavine adenine dinucleotide.

Biochemistry, 1978 Oct 31, 17(22), 4750 - 5
Alternative hydroxylases for the aerobic and anaerobic biosynthesis of ubiquinone in Escherichia coli; Alexander K et al.; The synthesis of ubiquinone under anaerobic conditions was examined in a variety of strains of Escherichia coli K12 . All were shown to synthesize appreciable quantities of ubiquinone 8 when grown anaerobically on glycerol in the presence of fumarate . Under these conditions, ubiquinone 8 was in most cases the principal quinone formed, and levels in the range 50--70% of those obtained aerobically were observed . Studies with mutants blocked in the various reactions of the aerobic pathway for ubiquinone 8 synthesis established that under anaerobic conditions three alternative hydroxylation reactions not involving molecular oxygen are used to derive the C-4, -5, and -6 oxygens of ubiquinone 8 . Thus, mutants blocked in either of the three hydroxylation reactions of the aerobic pathway (ubiB, ubiH, or ubiF) are each able to synthesize ubiquinone 8 anaerobically, whereas mutants lacking the octaprenyltransferase (ubiA), carboxy-lyase (ubiD), or methyltransferases (ubiE or ubiG) of the aerobic pathway remain blocked anaerobically . The demonstration that E . coli possesses a special mechanism for the anaerobic biosynthesis of ubiquinone suggests that this quinone may play an important role in anaerobic metabolism.

Biochemistry, 1978 Oct 31, 17(22), 4745 - 50
Three hydroxylations incorporating molecular oxygen in the aerobic biosynthesis of ubiquinone in Escherichia coli; Alexander K et al.; The biosynthetic origin of the oxygen atoms of ubiquinone 8 from aerobically grown Escherichia coli was studied by 18O labeling . An apparatus was developed which allowed the growth of cells under a defined atmosphere . Mass spectral analysis of ubiquinone 8 from cells grown under highly enriched 18O2 showed that three oxygen atoms of the quinone are derived from molecular oxygen . It was established that the molecular oxygen is incorporated into the two methoxyl groups (at C-5 and C-6) and one of the carbonyl positions of the ubiquinone molecule by demonstrating that only one of the incorporated oxygens will exchange with water under acidic conditions that specifically catalyze the exchange of carbonyl, but not methoxyl, oxygens . That the C-4 carbonyl oxygen is derived from molecular oxygen was shown by the incorporation of three atoms of 18O2 into ubiquinone 8 biosynthesized from added 4-hydroxybenzoic acid . Comparison of ubiquinone 8 and menaquinone 8 from E . coli grown under 18O2 confirmed that the labeled carbonyl oxygen of the {18O2}ubiquinone 8 is incorporated biosynthetically and not by chemical exchange in the cell . It is concluded that the three hydroxylation reactions involved in the pathway for the aerobic biosynthesis of ubiquinone are all catalyzed by monooxygenases . The implications of this study for the anaerobic biosynthesis of ubiquinone 8 in E coli are discussed.

Mol Gen Genet, 1978 Oct 30, 166(2), 141 - 9
Electron microscopic analysis of in vitro transcriptional complexes: mapping of promoters of the coliphage T5 genome; Stuber D et al.; Transcriptional complexes formed in vitro with coliphage T5 DNA as template were analyzed by electron microscopy and the number and location of starting sites utilized by E . coli RNA polymerase were determined . Of the 40 promoters characterized in this way, 6 map in the two terminal "pre-early" regions, 29 in the "early" and 5 in the "late" region . The direction of transcription within the different regions determined in this study agrees with earlier findings derived from RNA synthesized in vivo.

Mol Gen Genet, 1978 Oct 30, 166(2), 211 - 6
Genetic mapping of a putative temperature-sensitive transcription mutation in Escherichia coli K12; Jabbar MA et al.; A putative temperature-sensitive transcription mutant described earlier (Jabbar and Jayaraman, 1976) has been genetically mapped . The locus maps at 38 min to the left of aroD . The mutation is recessive to the wild type and it affects a gene probably other than the genes coding for the alpha and beta subunits of phenylalanine tRNA synthetase and protein synthesis initiation factor IF-3 which also map in the same region.

Mol Gen Genet, 1978 Oct 30, 166(2), 187 - 92
Major proteins of the outer cell envelope membrane of Escherichia coli K12: multiple species of protein I differ in primary structure; Gamon K et al.; Protein I, one of the major outer membrane proteins of E . coli in most K12 strains is represented by two very similar polypeptides Ia and Ib . Sequential mutations (involving selections for phage resistance) can lead to loss of proteins Ia and Ib . Among "revertants" of such Ia-Ib- mutants clones exist that instead of Ia or Ib produce a third species of protein I, polypeptide Ic . Ichihara and Mizushima {J . Biochem . 83, 1095--1100 (1978)} have shown that proteins Ia and Ib exhibit differences in primary structure . Here evidence is presented indicating that protein Ic also is not identical in primary structure with Ia or Ib . Thus, 3 very similar structural genes appear to exist for the protein I species known to date, and that for Ic normally is silent . Introduction of a functional Ic locus into a Ia+ Ib+ strain caused expression of all three proteins with a reduced rate of synthesis of protein Ia.

Wien Klin Wochenschr, 1978 Oct 27, 90(20), 744 - 7
{The influence of surgery upon leucocyte function (author's transl)}; Zielinski C et al.; 14 patients who underwent a standardized total hip joint replacement were investigated in order to detect postoperative impairment of chemotactic or phagocytic function of their polymorphonuclear leucocytes . A chemotaxis assay in modified Boyden {3} chambers and the nitroblue-tetrazolium assay were used . 25 healthy control persons served for the assessment of normal values and the reproducibility of the respective test . Patients were investigated preoperatively and on the first, third and sixth postoperative day . While phagocytosis remained unchanged throughout the period of investigation, chemotactic leucocyte function was regularly significantly depressed on the first postoperative day . The defect in postoperative chemotaxis might, despite of an unimpaired phagocytic capacity, contribute towards an increased risk of postoperative infections.

Mol Gen Genet, 1978 Oct 25, 166(1), 25 - 9
On the role of recA gene product in genetic recombination: an analysis by in vitro packaging of recombinant DNA molecules formed in the absence of protein synthesis; Kobayashi I et al.; The role of the recA gene product of Escherichia coli in genetic recombination was examined in a system where recombination takes place in the absence of protein synthesis . recA200 bacteria were infected with two mutant strains of phage lambda in the presence of chloramphenicol and rifampin, and the resulting recombinant DNA molecules were measured by in vitro packaging . When recA200 bacteria grown at a temperature that is permissive for RecA phenotype were transferred to a temperature that is restrictive for RecAa phenotype in the presence of the inhibitors, recombination of the infecting phages was severely blocked . This result shows that the recombination activity of the recA200 cells is inactivated by the change of temperature even in the absence of protein synthesis . The most likely explanation of this result is that the recA protein is directly involved in the recombination detected in the presence of chloramphenicol and rifampin.

J Biol Chem, 1978 Oct 25, 253(20), 7282 - 8
Purification, separation, and characterization of two molecular forms of D-1-amino-2-propanol:NAD+ oxidoreductase activity from extracts of Escherichia coli K-12; Campbell RL et al.; D-1-Amino-2-propanol:NAD+ oxidoreductase activity, which catalyzes the second step in a pathway wherein L-threonine is converted to D-1-amino-2-propanol via the intermediate formation of aminoacetone, has been purified 500-fold from Escherichia coli K-12 . Although the enzyme catalyzes the oxidation of certain diols as well as 1-amino-2-propanol, it is completely specific for the D-isomer of the amino alcohol and for NAD+ . Two molecular forms (designated Form L and Form S) of the oxidoreductase, both of which are catalytically active, have been separated by gel filtration on Sephadex G-200; apparently, Form L is converted to Form S by dissociation (Form L leads to Form S) . Molecular weight determinations indicate that the two forms of the enzyme are different not only in size but also in shape; Form L apparently is an asymmetric tetramer of Form S . The two molecular species have similar catalytic properties . Both exhibit the same pH optimum of 8.6, have nearly identical apparent Km values for substrate and cosubstrate, are equally sensitive to inhibition by p-mercuribenzoate and N-ethylmaleimide, and show the same specificity for cosubstrate . Neither form of the enzyme has an absolute requirement for added thiol compounds or divalent metal ions.

J Biol Chem, 1978 Oct 25, 253(20), 7145 - 8
Autophosphorylation of rabbit skeletal muscle cyclic AMP-dependent protein kinase I catalytic subunit; Chiu YS et al.; The catalytic subunit of rabbit skeletal muscle cyclic AMP-dependent protein kinase I can catalyze self-phosphorylation . The autophosphorylation reaction uses ATP as the phosphoryl donor, requires Mg2+, and is inhibited by polyarginine . Prior treatment of the catalytic subunit with Escherichia coli alkaline phosphatase in the presence of bovine serum albumin greatly enhances the autophosphorylation of the subunit . The protein-bound phosphate is stable in acid but labile in base . Incubation of the 32P-labeled phosphoenzyme with histones led neither to the phosphorylation of histones nor to a loss of radioactivity from the phosphoenzyme . The results suggest that the phosphoenzyme does not represent an intermediate of the phosphotransferase reaction.

J Biol Chem, 1978 Oct 25, 253(20), 7490 - 5
Purification and characterization of DNA-dependent ATPase II from Escherichia coli; Richet E et al.; A new DNA-dependent ATPase was isolated and purified from soluble extracts of Escherichia coli . This enzyme, called ATPase II, has a molecular weight of 86,000 and exists in a monomeric state . It degrades ATP (or dATP) to ADP (or dADP) and Pi in the presence of magnesium and requires a double-stranded polynucleotide as cofactor . A correlation between the efficiency as cofactor and the melting point of the polynucleotide has been found; the lower the melting temperature, the higher the stimulation of ATPase II . The enzyme binds to single-stranded DNA and poly{d(A-T)} copolymer, but not to the double-stranded circular DNA (Form I) of simian virus 40.

J Biol Chem, 1978 Oct 25, 253(20), 7355 - 60
Immunological comparison of the proteins of chicken and rat liver ribosomes; Fischer N et al.; A comparison of the proteins of chicken and rat liver ribosomes using immunochemical techniques was undertaken . The procedures included quantitative precipitation, passive hemagglutination, and immunodiffusion on Ouchterlony plates . The results indicate that antisera specific for chicken or rat liver ribosomes recognize only about 20% of common determinants . While there are important reservations, the results suggest extensive differences in the proteins of rat and chicken liver ribosomes . Despite those differences, rat and chicken liver ribosomal proteins maintain some homologous sequences present in bacterial ribosomal proteins . An enriched antibody preparation against chicken 80 S ribosomes inhibited the poly(U)-directed synthesis of polyphenylalanine and the elongation factor G (EF-G)-catalyzed binding of {3H}GDP to Escherichia coli ribosomes . Thus, chicken liver ribosomes, like ribosomes from rat liver and yeast, must have proteins homologous with those of E . coli ribosomes.

Biochim Biophys Acta, 1978 Oct 24, 520(3), 498 - 504
An easy and efficient procedure for the isolation of pure DNA restriction fragments from agarose gels; Ledeboer AM et al.; A new procedure is developed to isolate DNA from agarose gels . Using a kind of blotting technique, DNA is isolated from the gel . It is shown that the isolated DNA can be used for fragmentation by restriction endonucleases, synthesis of complementary RNA by DNA-dependent RNA polymerase from Escherichia coli and nick translation . The procedure gives a high recovery and is easy to perform.

Mol Gen Genet, 1978 Oct 24, 165(3), 331 - 41
Mapping of RP4 plasmid using deletion mutants of pAS8 hybrid (RP4--ColE1); Sakanyan VA et al.; We used the hybrid plasmid pAS8 in order to conduct the genetic analysis of RP4 plasmid . The presence of two replicons in the hybrid plasmid permitted to expand the spectrum of deletion mutants of RP4 isolated, which are capable to autonomous replication . The shortening of the hybrid plasmid was achieved by P22 transduction, by induction of deletion mutants using mitomycin C, as well as by seletion of Tra- mutants on the basis of resistance of cells to P-specific phages . These techniques have lead to isolation of clones possessing different combinations of plasmid resistance determinants . Comparison of phenotypic characteristics of deletion plasmids pAS9, pAS10, pAS11, pAS12 and pAS10-2 permitted to propose the map for pAS8 plasmid with the following sequence of markers: tra--kam--ColE1--amp--tet.. . Heteroduplex analysis of deletion mutants of pAS8 permitted to construct a physical map and to elaborate in greater detail the functional map of RP4 plasmid . The correlation between the ability of mutants to replicate in polA(TS) strain at nonpermissive conditions and the length of the deleted segment permitted to map rep genes of RP4 on a region with coordinates 9.8--17.3 kb . A relationship between the manifestation of incompatibility of mutants with Inc P-1 plasmids and the length of deletions points out that inc genes are located on DNA region with coordinates 2.1--9.8 kb . The analysis of replication of deletion mutants and the manifestation of incompatibility just as of the data about the size of appropriate deletions permitted to make the conclusion about the functional and genetic independence of the replication control and incompatibility control in RP4 plasmid.

Mol Gen Genet, 1978 Oct 24, 165(3), 295 - 304
The control region of the F sex factor DNA transfer cistrons: restriction mapping and DNA cloning; Thompson R et al.; A restriction endonuclease map of EcoRI fragment f6 of F sex factor DNA was constructed and aligned with pre-existing physical and genetic maps . Results of genetic complementation tests and analysis of proteins synthesized in minicells from PstI and BglII sub-fragment clones, or from a specific BglII fragment deletion, have allowed mapping of the locations of the origin of DNA transfer and many of the transfer genes known to lie on f6 . The proteins detected account for 78% of the coding capacity of fragment f6.

Mol Gen Genet, 1978 Oct 24, 165(3), 265 - 8
Genes encoding ribosomal proteins S16 and L19 form a gene cluster at 56.4 min in Escherichia coli; Isono K; A mutant of Escherichia coli which was isolated for temperature-sensitive growth was found to harbour a structural alterations in protein S16 (Isolo et al., 1978) . The mutation was localized by matings with various Hfr strains and by Plkc-mediated transduction . The results showed that it mapped very close to the gene coding for L19 protein which has been placed at 56.4 min (Kitakawa and Isono, 1977), indicating that it most likely forms a new ribosomal protein-gene cluster.

Biochim Biophys Acta, 1978 Oct 24, 520(3), 568 - 76
The mechanism of the aminoacylation of transfer ribonucleic acid . The kinetics and stoichiometry of the lysis of aminoacyl-tRNA; Jakubowski H et al.; It is often stated that the aminoacylation of transfer RNA proceeds in discrete steps: (formula: see article) . If this is a complete description of the reaction, the reverse overall formation of ATP should not be more rapid than the formation of Enz . (AA approximately AMP) . We show for four different amino acid:tRNA ligases that lysis of AA-tRNA (with PPi and AMP) to ATP is faster than lysis of AA-tRNA (with AMP only) to Enz . (AA approximately AMP) . This requires that the transition state proceeds from a quaternary complex of PPi, AMP, AA-tRNA and Enz . From the law of microscopic reversibility, this requires that in the forward reaction the AA-tRNA bond be formed before PPi leaves the enzyme complex . Therefore, the forward reaction passes through the quaternary complex Enz . ATP . AA . tRNA . (In view of recent evidence of the specific requirement of two cations, the complex is accurately described as senary).

Biochim Biophys Acta, 1978 Oct 24, 520(3), 539 - 54
A cloned Drosophila DNA fragment which codes for a 4 S RNA species; Schedl TB et al.; A collection of random Drosophila melanogaster DNA fragments cloned individually in Escherichia coli was screened for the presence of sequences complementary to the 4 S, 5 S and 5.8 S RNA species produced in the D . melanogaster Kc tissue culture line . Four D . melanogaster DNA fragments were found which possessed sequences complementary to the 4 S RNA species but not complementary to the 5 S or 5.8 S RNA . One such cloned fragment (6.81 kilobase in length) was characterized further . It hybridizes in situ to region 22A-C of the left arm of chromosome 2 and does not contain repetitive sequences detectable by renaturation (cot) analysis . This same region was reported earlier by Steffensen and Wimber (Genetics (1971) 69, 163--178) to hybridize in situ to bulk tRNA extracted from D . melanogaster.

Nature, 1978 Oct 19, 275(5681), 611 - 7
DNA sequence of the mini-insertion IS2--6 and its relation to the sequence of IS2; Ghosal D et al.; In polar IS2 abolishes galactose operon expression . Operon activity is restored by a 108 base pair mini-insertion within IS2 called IS2--6 . The DNA sequences of the gal operon-IS2 junction, the parental IS2 region undergoing sequence rearrangements and IS2--6 itself are reported . IS2--6 is composed of sequence intervals present in both strands of IS2.

Biochim Biophys Acta, 1978 Oct 19, 513(1), 78 - 88
Membrane-bound cooperative enzymes . Stokes' radii, Hill plots and membrane fluidity in the regulation of adenosinetriphosphatase from Escherichia coli; Sineriz F et al.; The soluble Ca2+-ATPase from Escherichia coli had a distinctive behavior with respect to inhibition by Na+ measured at 36 degrees C and 19 degrees C . At the first temperature the Hill plots are linear and show a slope of 1.1 while at 19 degrees C the plots are biphasic, with slopes of 1.8 and 0.8 before and after the break, respectively . The break occurs at about 50 nM NaCl . Gel chromatography was performed in jacketed Sepharose 4B columns kept at 2 temperatures in the presence of different concentrations of NaCl . It was found that the Stokes' radius of the enzyme was dependent on the temperature and on the salt concentration . Equilibrium sucrose gradients run at 19 degrees C showed that the sedimentation constant of the enzyme remained constant irrespective of the NaCl concentration used . It is concluded that a "folding" of the enzyme takes place in the presence of NaCl, the process being complete at about 50 mM NaCl at 19 degrees C and at about 20 mM at 36 degrees C . The results are in excellent agreement with the kinetic data: the "folded" or "compact" configuration would show no cooperative response towards Na+ while the "expanded" conformer would present strong cooperativity . This is also in agreement with the results obtained with the enzyme embedded in the membrane: when the membrane is fluid a high n value (Hill coefficient) is found; when the membrane is more rigid the value of n falls . A model explaining all our results is proposed and discussed.

Biochim Biophys Acta, 1978 Oct 19, 513(1), 31 - 42
The polymorphic phase behaviour of phosphatidylethanolamines of natural and synthetic origin . A 31P NMR study; Cullis PR et al.; 1 . The polymorphic phase behaviour of aqueous dispersions of phosphatidylethanolamines isolated from human erythrocytes, hen egg yolk and Escherichia coli have been investigated employing 31P NMR techniques . All species exhibit well defined, reversible bilayer to hexagonal (H11) phase transitions as the temperature is increased . The temperatures at which these transition take place (10, 25--30 and 55--60 degrees C for erythrocyte, egg yolk and E . coli phosphatidylethanolamine, respectively) are sensitive to the fatty acid composition, occurring at a temperature up to 10 degrees C above the high temperature end of the hydrocarbon phase transition as detected by differential scanning calorimetry . In some cases the bilayer to hexagonal (H11) transitions may also be detected employing calorimetric techniques . 2 . The addition of equimolar concentrations of cholesterol to these naturally occurring phosphatidylethanolamines does not dramatically affect the bilayer-hexagonal (H11) transition temperature, producing changes of up to 10 degrees C . 3 . 18 : 1t/18 : 1t phosphatidylethanolamine undergoes the bilayer to hexagonal (H11) phase transition as the temperature is increased through the interval 50--55 degrees C . Alternatively, hydrated 12 : 0/12 : 0 phosphatidylethanolamine remains in the bilayer phase at temperatures up to 90 degrees C (50 degrees C above the hydrocarbon phase transition temperature) . 4 . The presence of 100 mM NaCl or 10 mM CaCl2 in aqueous dispersions of egg yolk phosphatidylethanolamine does not alter the temperature-dependent polymorphic phase behaviour significantly . However, at 40 degrees C, increasing the p2H above 8.0 results in progressive inhibition of the hexagonal (H11) phase and the appearance of a phase possibly of cubic structure at p2H 9.0 . At p2H 10.0 the bilayer phase is preferred . 5 . It is suggested that in biomembranes containing phosphatidylethanolamine as a majority species (such as that of E . coli) the fatty acid composition may primarily reflect the need to maintain bilayer structure . Alternatively, it is pointed out that in mammalian membranes such as that of the erythrocyte, phosphatidylethanolamine tends to destabilize bilayer structure . The resulting possibility that transitory non-bilayer lipid configurations may occur may be directly related to many important properties of biological membranes.

Biochemistry, 1978 Oct 17, 17(21), 4487 - 92
Association of Escherichia coli lac repressor with poly{d(A-T)} monitored with 8-anilino-1-napthalenesulfonate; Worah DM et al.; The association of lac repressor with poly{d(A-T)} was monitored with the fluorescent prob 8-anilino-1-naphthalenesulfonate (Ans) . Excess poly{d(A-T)} decreased the emission intensity of the repressor--Ans complex by 30% . Fluorescence titrations indicated that 33 +/- 4 base pairs were required to bind all of the repressor . Sedimentation studies indicated, however, that all of the repressor sedimented as a protein--DNA complex with as few as 10 to 15 base pairs per tetramer, even in the presence of Ans . These data are interpreted with two models: one where repressors bind to both sides of the DNA (Butler, A . P., et al . (1977) Biochemistry 16, 4757: Zingsheim, H.P., et al . (1977) J . Mol . Biol . 115, 565), the other where a double layer of repressors bind to a single side of the DNA . Removal of the amino-terminal regions from the repressor decreased the fluorescence from bound Ans by 77% . The amino-terminal fragments alone did not enhance Ans fluorescence.

Biochemistry, 1978 Oct 17, 17(21), 4480 - 6
Binding of recrystallized and chromatographically purified 8-anilino-1-naphthalenesulfonate to Escherichia coli lac repressor; York SS et al.; 8-Anilion-1-naphthalenesulfonate (Ans), recrystallized from water as the magnesium salt, contains a fluorescent impurity representing 0.3% of the absorbance at 351 nm . This impurity can be removed by Sephadex LH-20 chromatography . The chromatographic and spectral properties of this impurity suggest that it is bis(Ans), a dimer of Ans . This bis(Ans) impurity makes a significant contribution to the fluorescence increment observed when lac repressor is added to recrystallized Ans . This occurs because bis(Ans) binds much more tightly to this protein than does Ans . The dissociation constant divided by the number of binding sites per subunit is 3.1 X 10(-6) M for bis(Ans); the corresponding value for Ans is greater than 1 X 10(-4) M . Because of their differing absorption spectra, the impact of this bis(Ans) impurity is especially large with excitation wavelengths above 400 nm . Users of recrystallized Ans should consider the potential consequences of this impurity whenever working with a protein to which Ans binds weakly.

Mol Biol Rep, 1978 Oct 16, 4(3), 181 - 4
A method for purification of peptides from hydrolysates of proteins modified by chemically active analogues of substrates containing cis-diol groups; Nevinsky GA et al.; A simple and rapid column procedure is described for the isolation from protein hydrolysates of peptides containing covalently bound substrate analogues with cis-diol groups . The method is based on complex formation between the cis-diol groups of peptide-bound compounds and dihydroxyborylic groups of a dihydroxyborylaminoethyl cellulose column . The method is useful for isolation of peptide(s) located in or near the active centre of enzymes after their affinity labelling by chemically active analogues of natural substrates like ribonucleotides, sugars, etc.

Eur J Biochem, 1978 Oct 16, 90(3), 571 - 80
Involvement of ribosomal protein S1 in the assembly of the initiation complex; van Dieijen G et al.; Antibodies against ribosomal protein S1 (anti-S1) have been used to determine the function of S1 in the partial reactions involved in the translation of MS2 RNA in vitro . Vacant ribosomes are fully sensitive to the antibodies, whereas elongating ribosomes are resistant . We have determined at which stage of translation the resistance to anti-S1 is acquired . We find that insensitivity to anti-S1 already arises upon mixing 30-S subunits with MS2 RNA . Apparently the two particles form a complex in which S1 is functionally protected against its antibody . Complex formation depends on elevated temperature, a suitable ionic environment and it is stimulated by the initiation factor IF-3 . It does not depend on IF-1, IF-2 or fMet-tRNA . Thus ribosomes have the potential to recognize the messenger in the absence of fMet-tRNA . Protein S1 appears directly involved in this primary recognition reaction.

Eur J Biochem, 1978 Oct 16, 90(3), 537 - 46
Evidences for the existence of two steps in DNA replication obtained in toluene-treated Escherichia coli; Forterre P et al.; Toluene-treated Escherichia coli can synthesize DNA in the presence of precursors and ATP {Moses, R.E . & Richardson, C.C . (1970) Proc . Natl Acad . Sci . U.S.A . 67, 674--681} . The replacement of ATP by another NTP or dNTP leads to the premature arrest of the reaction . Residual synthesis in the presence of an NTP or dNTP other than ATP differs from the complete reaction in the presence of ATP because it is less sensitive to nalidixic acid and novobiocin and because its maximal activity can be obtained with lower concentrations of dNTP or shorter times of toluene treatment . However, like the complete reaction, residual synthesis occurs at the replication fork pre-existing in vivo at the time of toluenization, produces short and long pieces of DNA, is inhibited by arabinosyl-adenine triphosphate, azide or mitomycin C, and is dependent on the dnaE, DNAB and dnaG gene products . We conclude from these data that ATP is specifically required for a step in DNA replication which involves the activity of DNA gyrase, the target of nalidixic acid and novobiocin {Higgins, N.P., Peebles, C.L., Sugino, A . & Cozzarelli, N.R . (1978) Proc . Natl Acad . Sci . U.S.A . 75, 1773-1777} . In the absence of DNA gyrase activity, short DNA pieces are formed and sealed but only a limited amount of the chromosome can be replicated (residual synthesis) . In the presence of DNA gyrase activity, DNA synthesis can occur on a longer portion of the chromosome (complete synthesis).

Mol Biol Rep, 1978 Oct 16, 4(3), 153 - 6
30S ribosomal proteins cross-linked to 16S RNA by periodate oxidation followed by borohydride reduction; Rinke J et al.; Gel electrophoretic techniques have been used to reexamine the RNA-protein cross-linking reaction induced by periodate oxidation and borohydride reduction of 30S ribosomal subunits . The results show that a number of 30S ribosomal proteins become attached to intact 16S RNA by this method, in addition to those already published . It follows that this cross-linking technique as it stands is of little value as a topographical probe of the environment of the 3'-terminus of the 16S RNA.

Schweiz Med Wochenschr . 1978 Oct 14;108(41):1608.
{Proliferative activity and bacteriostatic capacity of human alveolar macrophages (proceedings)}; Schildknecht O et al.; Human alveolar macrophages were collected by bronchopulmonary lavage and their proliferation activity and bacteriostatic capacity determined in vitro . Compared with blood monocytes the alveolar macrophages show a higher degree of differentiation with a very high bacteriostatic capacity and no proliferation acitivity . There were no major differences between alveolar macrophages from healthy individuals, heavy smokers and patients with bronchogenic cancer.

Biochim Biophys Acta, 1978 Oct 12, 526(2), 418 - 28
Nucleosidediphosphate kinase of Escherichia coli, a periplasmic enzyme; Roisin MP et al.; The ATP-ADP exchange activity previously described in a membrane farction of Escherichia coli appeared after a cold osmotic shock according to Neu and Heppel ((1965) J . Biol . Chem . 240, 3685--3692) in the shock fluid . Membranes derived from shocked cells had no activity . The enzyme responsible for this activity has been purified 125-fold and catalyzed the transfer of a phosphoryl radical from ribonucleosidetriphosphates (NTPs) to ribonucleosidediphosphates (NDPs); this is, therefore, a non-specific nucleosidediphosphate kinase (ATP:nucleosidediphosphate phosphotransferase, EC 2.7.4.6) . The activity required the presence of a divalent cation, Mg2+, Mn2+ or Ca2+ at a unity mol/mol ratio of nucleotide for maximal activation . The enzyme exhibited simple saturation kinetics with respect to the phosphate donor but inhibition by excess substrate was observed upon increasing phosphate acceptor . The kinetics of the reaction indicated an ordered bi-molecular ping-pong reaction mechanism . Differential heat sensitivity of the enzyme whether it is heated alone with ATP, ADP or Mg2+ opens possibilities to study different enzyme-substrate complexes.

Nature, 1978 Oct 12, 275(5680), 505 - 10
Synthesis of an ovalbumin-like protein by Escherichia coli K12 harbouring a recombinant plasmid; Mercereau-Puijalon O et al.; A cloned DNA transcript of ovalbumin mRNA was cut a few nucleotides away from the initiator codon, and fused in phase to the beginning of the Escherichia coli beta-galactosidase gene . The hybrid gene has been cloned in E . coli where it produces large amounts of an ovalbumin-like protein.

J Biol Chem, 1978 Oct 10, 253(19), 7047 - 50
The ribosomal protein L24 of Escherichia coli is an assembly protein; Spillmann S et al.; Incubation of 50 S subunits with 4.2 M LiCl leads to 4.2c cores and the complementary split protein fraction SP4.2, the latter containing quantitatively L24 . L24 was removed from the split fraction by means of CM-cellulose chromatography . Partial and total reconstitution experiments performed with this protein preparation in the absence and presence of L24 demonstrate the crucial role of L24 in the early stage of assembly . However, this protein is dispensable for the subsequent steps of the in vitro assembly . 50 S subunits lacking L24 are fully active in the translation of artificial (poly(U)) and natural (R17 RNA) mRNA, indicating that L24 is not involved in any function of protein synthesis of the mature ribosome . It is therefore a mere assembly protein.

J Biol Chem, 1978 Oct 10, 253(19), 6931 - 3
Nucleotide sequence of the L-arabinose regulatory region of Escherichia coli K12; Smith BR et al.; The nucleotide sequence of a 250-base pair segment of L-arabinose operon DNA containing the 150-base pair regulatory region has been determined . This segment includes the promoter for rightward araBAD transcription, pBAD, the promoter for leftward araC transcription, pC, and sites responsible for repression.

J Biol Chem, 1978 Oct 10, 253(19), 6756 - 60
Characterization of a restriction enzyme from Escherichia coli K carrying a mutation in the modification subunit; Buhler R et al.; The restriction enzyme from a restriction and modification-deficient strain of Escherichia coli K mutated in the modification gene (hsdM) has been purified using an in vitro complementation assay with a mutant restriction enzyme from a strain lacking only restriction . The restriction enzyme from the hsdM mutant lacks all of the activities that are associated with the wild type enzyme: binding of unmodified DNA to filters, cleavage, or methylation of unmodified DNA and ATP hydrolysis . It is shown that the enzyme from this hsdM mutant cannot bind S-adenosylmethionine, an allosteric effector in the restriction reaction . In the absence of enzyme activation by S-adenosylmethionine, no binding to unmodified DNA takes place . A comparison with other mutant restriction enzymes allows us to outline the biochemical role of the subunits of the E . coli K restriction endonuclease.

J Biol Chem, 1978 Oct 10, 253(19), 6863 - 5
The tyrosine free radical in ribonucleotide reductase from Escherichia coli; Sjoberg BM et al.; One of the two nonidentical subunits of ribonucleotide reductase from Escherichia coli, protein B2, contains an organic free radical required for enzyme activity . Earlier isotope subtitution experiments (Sjoberg, B.-M., Reichard, P . Graslund, A., and Ehrenberg, A . (1977) J . Biol . Chem . 252, 536-541) demonstrated that the radical was localized to a tyrosine residue of the enzyme and suggested that the spin density of the radical was centered at the methylene carbon of tyrosine . However, additional isotope substitution experiments now show that the spin density of the radical must be delocalized over the aromatic ring of the tyrosine residue.

J Biol Chem, 1978 Oct 10, 253(19), 6666 - 8
A K+ transport ATPase in Escherichia coli; Epstein W et al.; A K+ -stimulated ATPase in membranes of Escherichia coli has been identified as an activity of the Kdp system, and ATP-driven K+ transport system . Three characteristics support association of the ATPase with the Kdp system: (i) ATPase and Kdp transport are both repressed by growth in media containing high concentrations of K+; (ii) the ATPase and Kdp system accept only K+ as substrate, neither requires Na+ nor accepts Rb+ as a substrate; (iii) the affinity of the ATPase and that of th Kdp system for K+ is similar and is altered by mutations in the structural genes of the Kdp system . Discovery of an ATPase associated with a bacterial transport system suggests functional similarities with the ATP-driven transport systems of animal cells.

J Biol Chem, 1978 Oct 10, 253(19), 6630 - 2
Nonspecific effect of m7GMP on protein-RNA interactions; Sonenberg N et al.; Cap analogs m7GMP and m7GDP inhibit binding of eukaryotic initiation factors to reovirus capped mRNA but also inhibit complex formation involving uncapped mRNA or 18 S rRNA . Furthermore, Escherichia coli DNA-dependent RNA polymerase binds 18 S rRNA and this interaction is also blocked by m7GMP . These results indicate that inhibition by cap analogs is not a stringent test for putative cap-specific binding between proteins and mRNA.

J Biol Chem, 1978 Oct 10, 253(19), 6627 - 9
Carbamyl phosphate synthetase of Escherichia coli uses the same diastereomer of adenosine-5'-{2-thiotriphosphate} at both ATP sites; Raushel FM et al.; Carbamyl phosphate synthetase from Escherichia coli has been shown to use only the A isomer of adenosine-5'-{2-thiotriphosphate} in both the ATPase reaction (MgATP HCO3- leads to MgADP + Pi) and the carbamyl phosphate synthesis reaction (2MgATP + HCO3- + L-glutamine leads to 2MgADP + Pi + carbamyl-P + L-glutamate) . The B isomer was less than 5% as reactive . In the reverse reaction, only the A isomer of adenosine-5'-{2-thiotriphosphate} is synthesized from adenosine-5'-{2-thiodiphosphate} and carbamyl-P as determined by 31P NMR and a coupled enzymatic assay with Cd2+- hexokinase . It is therefore proposed that carbamyl phosphate synthetase uses the same diastereomer of MgATP at both ATP sites.

J Biol Chem, 1978 Oct 10, 253(19), 7017 - 25
A spectral probe near the subunit catalytic site of glutamine synthetase from Escherichia coli . Reduced pyridoxal 5'-phosphate.enzyme complexes; Whitley EJ Jr et al.; In order to label phosphate binding sites, unadenylylated glutamine synthetase from Escherichia coli has been pyridoxylated by reacting the enzyme with pyridoxal 5'-phosphate followed by reduction of the Schiff base with NaBH4 . A complete loss in Mg2+-supported activity is associated with the incorporation of 3 eq of pyridoxal-P/subunit of the dodecamer . At this extent of modification, however, the pyridoxylated enzyme exhibits substantial Mn2+-supported activity (with increased Km values for ATP and ADP) . The sites of pyridoxylation appear to have equal affinities for pyridoxal-P and to be at the enzyme surface, freely accessible to solvent . At least one of the three covalently bound pyridoxamine 5'-phosphate groups is near the subunit catalytic site and acts as a spectral probe for the interactions of the manganese.enzyme with substrates . A spectral perturbation of covalently attached pyridoxamine-P groups is caused also by specific divalent cations (Mn2+, Mg2+ or Ca2+) binding at the subunit catalytic site (but not while binding to the subunit high affinity, activating Me2+ site) . In addition, the feedback inhibitors, AMP, CTP, L-tryptophan, L-alanine, and carbamyl phosphate, perturb protein-bound pyridoxamine-P groups . The spectral perturbations produced by substrate and inhibitor binding are pH-dependent and different in magnitude and maximum wavelength . Adenylylation sites are not major sites of pyridoxylation.

Med J Aust, 1978 Oct 7, 2(8), 348 - 52
Galactosaemia: case for neonatal screening illustrated by recent Australian experience; Masters P et al.; The varied presentation and clinical features of classical galactosaemia are illustrated by the case histories of seven babies born in Western Australia since January, 1962, and of two babies born in South Australia in whom diagnosis was made as a result of adding galactosaemia to the Guthrie screening programme in October, 1974 . All were shown to have a severe deficiency of galactose-1-phosphate uridyl transferase in their red blood cells . We compare our findings with those in 10 galactosaemic babies born in Victoria over a similar period, and show that in both groups these were two main modes of onset: acute and insidious . Jaundice and Escherichia coli infection were prominent in the 13 babies with an acute onset of galactosaemia, while poor weight gain, intermittent vomiting and cataracts were features of the five babies with an insidious onset . An enlarged liver was usually found in both groups . We discuss the various approaches to neonatal screening of galactosaemia in the light of experience in Massachusetts and South Australia . The use of cord blood can be expected to lead to diagnosis before babies with acute onset become ill, while the use of blood collected at five days for the Guthrie test avoids the collection of another routine sample for a relatively rare disorder . The result of red cell transferase assays of parents and siblings of our patients are discussed in relation to their implication for genetic counselling . The relevance of antenatal diagnosis to the prevention of possible intrauterine damage to an affected fetus is pointed out.

Biochim Biophys Acta, 1978 Oct 4, 512(3), 472 - 9
An estimate of the minimum amount of fluid lipid required for the growth of Escherichia coli; Jackson MB et al.; The lipid phase transition of Escherichia coli was studied by high sensitivity differential scanning calorimetry . A temperature sensitive unsaturated fatty acid auxotroph was used to obtain lipids with subnormal unsaturated fatty acid contents . From these studies it was concluded that E . coli can grow nromally with as much as 20% of its membrane lipids in the ordered state but that if more than 55% of the lipids are ordered, growth ceases . Studies with wild-type cells show that the phase transition ends more than 10 degrees C below the growth temperature when the growth temperature is either 25 degrees C or 37 degrees C.

Arch Microbiol, 1978 Oct 4, 119(1), 81 - 6
Effect of guanosine 5'-diphosphate 3'-diphosphate and related nucleoside polyphosphates on induction of tryptophanase and beta-galactosidase in permeabilized cells of Escherichia coli; Yoshimoto A et al.; Exogenous addition of guanosine and adenosine 5'-(mono, di and tri) phosphate 3'-diphosphates (pppGpp, ppGpp, pGpp, pppApp, ppApp and pApp) stimulated the synthesis of tryptophanase and beta-galactosidase in permeabilized cells of Escherichia coli . From the results obtained with ppGpp and pppApp, this effect appeared to be at a transcriptional level and depended greatly on the growth condition; the largest effect was observed in cells under shiftdown or grown on poor enrgy source . ppGpp and pppApp, unlike cyclic AMP, did not act to overcome the inhibition of enzyme induction by glucose, but in combination with cyclic AMP caused a synergistic stimulation effect . In the shiftdown cells, ppGpp and pppApp gave 30% or more stimulation effect on tryptophanase induction while cyclic AMP did not stimulate induction . There was therefore a pronounced difference between cyclic AMP and ppGpp or pppApp in stimulatory function.

Biochim Biophys Acta, 1978 Oct 4, 512(3), 525 - 38
Mg2+-ATPase as a membrane ecto-enzyme of human granulocytes . Inhibitors, activators and response to phagocytosis; Smolen JE et al.; (1) The Mg2+-ATPase of purified human granulocytes is located at the plasma membrane . Thus, no additional enzyme activity was detected when the cells were disrupted . Moreover, the Mg2+-ATPase activity of intact cells was inhibited by such poorly permeant reagents as diazotized sulfanilic acid and suramin . Finally, the enzyme activity of cell homogenates was recovered in particulate fractions . (2)The surface Mg2+-ATPase of human granulocytes had an apparent Km of 50 microns for ATP and displayed substrate inhibition . (3) The enzyme was not affected by ouabain, but was inhibited by N-ethyl malemide, sodium meta-periodate, suramin and diazotized sulfanilic acid . The enzyme was activated by cytochalasins B and D and by UDP . Activation by UDP was characterized by changes in the enzyme's apparent Km and V and by belief of substrate inhibition . (4)Internalization of surface membranes subsequent to phagocytosis of suitable particles did not result in depletion of Mg2+-ATPase from the cell surface . The enzyme activity did not decrease after exposure to several varieties of paraffin oil emulsion particles, even if the challenged cells had been pretreated with colchicine of cytochalasin B . (5) Since suramin, which inhibited Mg2+-ATPase, had no effect upon other granulocyte functions such as chemotaxis, superoxide anion generation, or phagocytosis, it is unlikely that the enzyme plays a major role in these functions.

Biochemistry, 1978 Oct 3, 17(20), 4318 - 23
Detection of the homology among proteins by immunochemical cross-reactivity between denatured antigens . Application to the threonine and methionine regulated aspartokinases-homoserine dehydrogenases from Escherichia coli K 12; Zakin MM et al.; The two isofunctional enzymes aspartokinases-homoserine dehydrogenases I and II from Escherichia coli K 12 are compared using immunochemical techniques . The antibodies raised against one of these two proteins when in its native state can only recognize the homologous antigen, whether it is native or denatured . Contrarily, the antibodies raised against one of these two proteins when in its denatured state can recognize both the homologous and heterologous denatured antigens . The existence of this cross-reaction only between the two denatured aspartokinases-homoserine dehydrogenases suggests that these two enzymes have some similarity since such a reaction is not detected with several other denatured proteins . The regions involved in this similarity are buried inside the native proteins, and become exposed only upon denaturation . The same results, the existence of a cross-reaction between denatured species and none between the native ones, is obtained with proteolytic fragments derived from these two proteins and endowed with homoserine dehydrogenase activity . This resemblance between the two aspartokinases-homoserine dehydrogenases suggests that these proteins derive from a common ancestor . It is also proposed that such a cross-reaction between two denatured proteins is evidence for an homology between their amino acid sequences, and that the use of denatured proteins as both immunogens and antigens could be useful in detecting sequence homologies.

Biochemistry, 1978 Oct 3, 17(20), 4348 - 58
Magnetic cross-relaxation among protons in protein solutions; Koenig SH et al.; The magnetic spin-lattice relaxation rates of solvent water nuclei are known to increase upon addition of diamagnetic solute protein . This enhancement of the relaxation rate is a function of magnetic field, and the orientational relaxation time of the protein molecules can be deduced from analysis of the field-dependent relaxation rates . Although the nature of the interactions that convey information about the dynamics of protein motion to the solvent molecules is not established, it is known that there is a contribution to the relaxation rates of solvent protons that plays no role in the relaxation of solvent deuterons and 17O nuclei . We show here that the additional interaction arises from a cross-relaxation process between solvent and solute protons . We introduce a heuristic three-parameter model in which protein protons and solvent protons are considered as two separate thermodynamic systems that interact across the protein-solvent interface . The three parameters are the intrinsic relaxation rates of each system and a cross-relaxation term . The sign of the latter term must always be positive, for all values of magnetic field, in order for magnetization energy to flow from the hotter to the cooler system . We find that the magnetic field-dependence of the cross-relaxation contribution is much like that of the remaining solvent proton relaxation, i.e., about the same as the deuteron relaxation field dependence . This finding is not compatible with the predictions of expressions for the cross-relaxation that have been used by other authors, but not applied to data over a wide range of magnetic field strength . The model predicts that the relaxation behavior of both the protein protons and the solvent protons is the sum of two exponentials, the relative contributions of which would vary with protein concentration and solvent isotopic composition in a fashion suggestive of the presence of two classes of protein protons, when there is in reality only one . This finding has immediate implications for the interpretation of published proton relaxation rates in complex systems such as tissues; these data should be reexamined with cross-relaxation taken into account.

Nucleic Acids Res, 1978 Oct, 5(10), 3959 - 73
Ribonucleotidyl transferase in preparations of partially purified DNA polymerase alpha of the sea urchin; Morris PW et al.; Three ribonucleotidyl transferase types have been described in the sea urchin: riboadenylate trnasferase, the DNA dependent RNA polymerases, and a DNA polymerase associated ribonucleotidyl transferase (Biochemistry 15:3106-3113, 1976) . In the present work this latter ribonucleotidyl transferase was found to purify with DNA polymerase alpha through phosphocellulose, DEAE-Sephadex and DNA cellulose and to cosediment at 6.5 S . This ribonucleotidyl transferase was active with Mn+2, but not Mg+2, on calf thymus DNA and poly(dC) . Other synthetic templates elicited DNA polymerase alpha but no ribonucleotidyl transferase activity . From alkaline hydrolysates of the poly(dC) directed GTP polymerization, we found Goh and Gp in a ratio of 1:16 indicating an average chain length of 17 residues after a 20 min reaction . Co-polymerization of GTP (5 micrometer) and dGTP (10 micrometer) yielded a non-random distribution of the ribonucleotide in the deoxyribonucleotide . The properties of this urchin ribonucleotidyl transferase are unlike any previously described eukaryotic transferase and the data is discussed with reference to the known properties of E . coli DNA polymerase I and the primase.

Nucleic Acids Res, 1978 Oct, 5(10), 3549 - 63
Specific termination of RNA polymerase synthesis as a method of RNA and DNA sequencing; Axelrod VD et al.; Termination of RNA synthesis with 3'-O-Methylnucleoside 5'-triphosphates have been studied using E . coli RNA polymerase holoenzyme and poly {d(A-T)} as well as unfractionated T7 D delta III DNA as templates . It was shown that the termination can be used for DNA sequencing . A sequence of a part of RNA synthesized from AI promoter of the DNA have been determined . Syntheses of four 3'-O-Methylnucleoside 5'-triphosphates are described.

J Bacteriol, 1978 Oct, 136(1), 441 - 3
Lack of lysogenic induction in "diaminopimelic acid spheroplasts"; Bailone A et al.; As part of an attempt to develop a semi-in vitro system of lysogenic induction, using spheroplasts of Escherichia coli K-12 lysogenic for prophage lambda, we prepared spheroplasts by depriving E . coli dap of diaminopimelic acid (DAP-spheroplasts) . DAP-spheroplasts made from E . coli (lambda cI857) were thermally inducible . However, DAP-spheroplasts of E . coli (lambda) were not inducible by UV light . Thus, it appears that a functional cell wall is required for UV induction of prophage lambda.

Avian Dis, 1978 Oct-Dec, 22(4), 717 - 20
Occurrence of Escherichia coli in feces of psittacine birds; Graham CL et al.; The feces of 125 psittacine birds, representing 12 species, were cultured on selective media to determine the presence of Escherichia coli . Only 13.6% (17) of the birds yielded E . coli.

Nippon Yakurigaku Zasshi, 1978 Oct, 74(7), 797 - 804
{Effect of alpha-mercaptopropionylglycine (alpha-MPG) and sodium dipropylacetate (DPA) on antibody formation (III) (author's transl)}; Mori H et al.; Mechanisms of the immunostimulative activity . In the present paper, an investigation was carried out to clarify the mechanisms regarding immunostimulative activity of alpha-MPG and DPA . Phagocytosis of peritoneal macrophage was enhanced by high concentration of alpha-MPG, but was unaffected with DPA in vitro . Mice were immunized with an i.v . injection of sheep erythrocytes and 3 days later spleen cells were isolated and incubated with alpha-MPG and DPA FOR 24 HR . Although neither drug affected the number of recovered and living cells, hemolytic plaque forming cells were increased with alpha-MPG and there was a tendency to increase with DPA . Phytohemagglutinin-P and/or lipopolysacchride E . coli-induced blast formation was not reinforced by either drug in spleen cells of mice, and no mitogenic activity was found in the spleen cells . In the early stage of immuno-response to polyvinylpyrrolidone as a T cell independent antigen, the titre of antibody showed no increase after either drug . alpha MPG and DPA apparently act as potentiators in antigen modifications of macrophages.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4891 - 5
An Escherichia coli mutant with an amino acid alteration within the signal sequence of outer membrane prolipoprotein; Lin JJ et al.; Lipoprotein has been purified from an Escherichia coli strain carrying a mutation in the structural gene for murein lipoprotein (mlpA) . Amino acid analysis of the purified mutant lipoprotein indicates that the mutant lipoprotein corresponds to the uncleaved prolipoprotein with a single amino acid replacement of glycine with aspartic acid . Automated Edman degradation has established the precise location of this amino acid substitution to be at the 14th residue of the prolipoprotein . This alteration in the signal sequence of prolipoprotein results in a failure of the mutated prolipoprotein to be processed . Furthermore, the structural alteration in the mutant lipoprotein appears also to have affected its topological localization in the mutant cell . Whereas lipoprotein in the wild-type strain is exclusively located in the outer membrane of the cell envelope, the membrane-bound lipoprotein in this mutant is recovered in both the inner and outer membranes of the cell envelope . The data suggest, however, that proteolytic cleavage of prolipoprotein to form mature lipoprotein is not essential for the translocation and assembly of lipoprotein into the outer membrane.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4833 - 7
Single base-pair alterations in the Escherichia coli trp operon leader region that relieve transcription termination at the trp attenuator; Stauffer GV et al.; We have isolated a set of regulatory mutants defective in transcription termination at the attenuator in the leader region of the Escherichia coli tryptophan (trp) operon . In vivo the mutants have 2- to 4-fold increased levels of expression of the trp operon above the level of the trpR parental strain . These levels are increased an additional 1.5- to 2-fold when the mutants are starved of tryptophan . Transcription termination at the trp attenuator was analyzed in vitro with DNA restriction fragments containing the termination-relief mutations . Whereas the frequency of readthrough transcription beyond the termination site is 5% with the wild-type DNA template, it is 46-76% when mutant DNAs are used as templates . The base change in the leader region of each mutant was determined by RNA and/or DNA sequencing . All the changes were between base pairs +116 and +132, in the G-C-rich segment of the leader region . The RNA residues between +114 and +134 of the leader transcript can form a stable stem and loop structure {deltaG approximately equal to -20 kcal (-84 kJ)} . All of the termination-relief mutations destabilize this structure (deltaG approximately equal to -9.0 to -10.5 kcal) . These results suggest that the efficiency of transcription termination may be dependent on the integrity of the secondary structure of the above segment of the transcript of the leader region.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4801 - 5
Complete nucleotide sequence of a 16S ribosomal RNA gene from Escherichia coli; Brosius J et al.; The complete nucleotide sequence of the 16S RNA gene from the rrnB cistron of Escherichia coli has been determined by using three rapid DNA sequencing methods . Nearly all of the structure has been confirmed by two to six independent sequence determinations on both DNA strands . The length of the 16S rRNA chain inferred from the DNA sequence is 1541 nucleotides, in close agreement with previous estimates . We note discrepancies between this sequence and the most recent version of it reported from direct RNA sequencing {Ehresmann, C., Stiegler, P., Carbon, P . & Ebel, J.P . (1977) FEBS Lett . 84, 337-341} . A few of these may be explained by heterogeneity among 16S rRNA sequences from different cistrons . No nucleotide sequences were found in the 16S rRNA gene that cannot be reconciled with RNase digestion products of mature 16S rRNA.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4798 - 800
Absolute configuration of the diastereomers of adenosine 5'-O-(1-thiotriphosphate): consequences for the stereochemistry of polymerization by DNA-dependent RNA polymerase from Escherichia coli; Burgers PM et al.; The diastereomers of uridyl-(3'-5')adenyl-O,O-phosphorothioate {Up(S)A} have been separated by high-performance liquid chromatography . Their identification as RP and SP follows from the RNase A digestion of these products . It was then shown, by the same method, that the R isomer is hydrolyzed by snake venom phosphodiesterase (PDEase) approximately 500 times faster than the S isomer . Similarly, the stereoisomer of adenosine 5'-O-(1-thiotriphosphate) (ATPalphaS), until now arbitrarily designated as isomer B, is hydrolyzed ca 400 times faster by PDEase than is isomer A . From these results it is concluded that the R isomers of Up(S)A and ATPalphaS, isomers B, have the same absolute configuration . It then follows that isomer A of ATPalphaS, the preferred of the two isomers as substrate for DNA-dependent RNA polymerase, has the S configuration . The implications for the stereochemistry of action of the latter enzyme are discussed.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4724 - 8
DNA sequence of the araBAD promoter in Escherichia coli B/r; Greenfield L et al.; The L-arabinose operon in Escherichia coli is a model system for the study of the control of gene expression . Maximal expression of the araBAD operon requires two positive control components: the araC protein-L-arabinose complex and the cyclic AMP receptor protein-cyclic AMP complex . Both araC protein and cyclic AMP receptor protein are required for the initiation of transcription of araBAD mRNA . We have used the plasmid pBR322 as a vector for cloning DNA fragments that contain the araBAD promoter . The cloned ara fragments were identified by both physical and genetic tests . A restriction map was constructed and the DNA sequence of the promoter was determined . The promoter contains a site that is similar to the RNA polymerase recognition sites in the galactose and lactose operons . It also contains a region similar to the known cyclic AMP receptor protein binding sites in the galactose and lactose operons.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4714 - 8
Escherichia coli recA gene product inactivates phage lambda repressor; Roberts JW et al.; Phage lambda repressor is inactivated and cleaved into two detectable fragments during incubation with purified Escherichia coli recA gene protein in vitro, in a reaction that requires ATP . This reaction reproduces the recA-dependent inactivation of repressor that occurs in vivo during induction of the SOS functions . The proteolytic activity may reside in the recA protein itself and may be a fundamental activity of it.

Biochem J, 1978 Oct 1, 175(1), 311 - 9
Purification of 3-phosphoglycerate kinase from diverse sources by affinity elution chromatography; Fifis T et al.; 1 . Affinity elution chromatography was used to purify phosphoglycerate kinase from a variety of sources . The choice of buffer pH for the chromatography was made according to the relative electrophoretic mobility of the enzyme from the species concerned . 2 . Outlines of the methods used to isolate the enzyme from over 20 sources are presented . The enzyme was purified from the muscle tissue of a variety of mammals, fish and birds, from liver of several animals, from yeast, Escherichia coli, and plant leaves . The more acidic varieties of the enzymes were purified by conventional gradient elution from ion-exchangers as affinity elution procedures were not applicable . 3 . The structural and kinetic parameters investigated show that phosphoglycerate kinase is evolutionarily a highly conservative enzyme; there were few differences in properties regardless of source or function (glycolytic, gluconeogenic or photosynthetic) . 4 . A detailed comparison of the enzyme preparations purified from bovine muscle and bovine liver failed to detect any significant differences between them; the evidence indicates that they are genetically identical.

Biochem J, 1978 Oct 1, 175(1), 193 - 8
Intramolecular coupling of active sites in the pyruvate dehydrogenase multienzyme complex of Escherichia coli; Danson MJ et al.; The intramolecular passage of substrate between the component enzymes of the pyruvate dehydrogenase multienzyme complex of Escherichia coli was examined . A series of partly reassembled complexes, varying only in their E1 (pyruvate decarboxylase, EC 1.2.4.1) content, was incubated with pyruvate in the absence of CoA, conditions under which the lipoic acid residues covalently bound to the E2 (lipoate acetyltransferase, EC2.3.1.12) chains of the complex become reductively acetylated, and the reaction then ceases . The fraction of E2 chains thus acetylated was estimated by specific reaction of the thiol groups in the acetyl-lipoic acid moieties with N-ethyl{2,3-14C}maleimide . The simplest interpretation of the results was that a single E1 dimer is capable of catalysing the rapid acetylation of 8-12 E2 chains, in good agreement with the results of Bates, Danson, Hale, Hooper & Perham {(1977) Nature (London) 268, 313-316} . This novel functional connexion of active sites must be brought about by transacetylation reactions between lipoic acid residues of neighbouring E2 chains in the enzyme complex . There was also a slow transacylation process between the rapidly acetylated lipoic acid residues and those that did not react in the initial, faster phase . This interaction was not investigated in detail, since it is too slow to be of kinetic significance in the normal enzymic reaction.

Mutat Res, 1978 Oct, 52(1), 37 - 47
Influence of the recF143 mutation of Escherichia coli K12 on prophage lambda induction; Armengod ME et al.; Prophage lambda induction in a recF143 mutant of E . coli K12 was studied . The recF143 (lambda) lysogen was inducible by UV irradiation or treatment with mitomycin C . However, the time required for the onset of derepression brought about by these treatments was longer in the recF143 mutant than in rec+ strains, suggesting that the induction pathway was altered in the recF143 mutant . The recF143 (lambda) lysogen was induced at very low doses of UV irradiation or mitomycin C treatment . Moreover, the presence of the recF143 mutation increased the sensitivity to thermal induction of a tif strain.

Mutat Res, 1978 Oct, 52(1), 25 - 35
Mutagenic interaction between near-(365 nm) and far-(254 nm)ultraviolet radiation in repair-proficient and excision-deficient strains of Escherichia coli; Tyrrell RM; The mutational interaction between radiation at 365 and 254 nm was studied in various strains of E . coli by a mutant assay based on reversion to amino-acid independence in full nutrient conditions . In the two repair-proficient strains (K12 AB 1157 and B/r), pre-treatment with radiation at 365 nm strongly suppressed the induction of mutations by far-UV, a phenomenon accompanied by a strong lethal interaction . The frequency of mutations induced by far-UV progressively declined with increasing dose of near-UV . Far-UV-induced mutagenesis to T5 resistance was almost unaltered by pre-treatment with near-UV . In AB 1886 uvrA there was no lethal interaction between the two wavelengths but the mutagenic interaction was synergistic . This synergism was maximal at a 365-nm dose of 8 X 10(5) J m-2 . It is proposed that in the wild-type strain, cells containing potentially mutagenic lesions are selectively eliminated from the population because of abortive excision of an error-prone repair-inducing signal . In excisionless strains, 365-nm radiation may be less damaging to the error-prone than to the error-free post-replication repair system . Alternatively, mutation may be enhanced because of the occurrence of error-prone repair of 365-nm lesions by a system that is not induced in the absence of 254-nm radiation.

Mutat Res, 1978 Oct, 52(1), 11 - 24
Bromouracil mutagenesis and mismatch repair in mutator strains of Escherichia coli; Rydberg B; A screening procedure based on the formation of papillae on individual bacterial colonies was used to isolate mutants of Escherichia coli with high mutation rates in the presence of bromouracil . Most of the mutants obtained had high spontaneous mutation rates and mapped close to the previously known mutators mutT, mutS, mutR, uvrE and mutL . Except for mutants of mutT type, these mutators also showed high mutability by bromouracil . Transfection experiments were performed with heteroduplex lambda DNA to test for mismatch repair . The results suggest a reduced efficiency of repair of mismatched bases in mutators mutS, mutR, uvrE and mutL, whereas mutants mapping as mutT appear normal . The results support a connection between spontaneous and bromouracil-induced mutability and repair of mismatched bases in DNA.

Mutat Res, 1978 Oct, 52(1), 1 - 9
The role of inducible gene rer of Escherichia coli K-12 in DNA repair and mutagenesis; Srivastava BS; Further characterization of a UV- and gamma-ray-sensitive mutant of Escherichia coli K-12 mutated in gene rer revealed that, as a result of this mutation: (1) neither bacterial capacity to excise thymine dimers from its DNA nor capacity to reactivate UV-irradiated phage lambda (Hcr+) was affected; (2) sensitivity to EMS and MC was increased; (3) WR of phage lambda was poor, whereas pre-irradiation growth of the mutant in MM only marginally restored WR; (4) the yield of UV-induced mutations was normal on MM, whereas on RM a decline below the spontaneous level was observed; and (5) induction of prophage by UV was not affected . The medium effect on UV sensitivity was largely post-irradiation . The rer recA double mutant was as UV sensitive as recA alone, and the media-dependent UV sensitivity exhibited by the rer strain disappeared in the double mutant . We provide further evidence to strengthen the earlier suggestion that rer might be involved in the control of replication of damaged DNA rather than participating directly in repair . It is further proposed that the rer+ gene is inducible and has a role in post-replication repair.

Infect Immun, 1978 Oct, 22(1), 143 - 7
Inhibition of the secretory activity of Escherichia coli heat-stable enterotoxin by indomethacin; Madsen GL et al.; The effect of indomethacin on the net intestinal accumulation of fluid induced by Escherichia coli heat-stable (ST) enterotoxin in the infant mouse model was examined . Indomethacin, when administered with ST enterotoxin, caused a striking decrease in net intestinal fluid accumulation . This inhibition of ST activity was dose dependent with various concentrations of indomethacin (P less than 0.01) . A significant inhibition of toxicity was also observed when indomethacin was given before (P less than 0.01) or after (P less than 0.02) ST enterotoxin challenge . No significant differences in fluid accumulation were observed between control mice treated with buffer alone and those challenged with only indomethacin . These data indicate that indomethacin markedly decreases the net intestinal fluid accumulation induced by E . coli ST enterotoxin . Further studies on the potential use of indomethacin in both the prophylaxis and the therapy of diarrheal diseases appear warranted.

Can J Microbiol, 1978 Oct, 24(10), 1277 - 80
Temperature-induced differences in growth rate and fatty acid composition in two strains of Escherichia coli 15T-; Crowe JL et al.; The saturated/unsaturated fatty acid ratio of Escherichia coli 15T- decreases almost threefold as growth temperature decreases from 43 to 27 degrees C, wheras the ratio of a fast-growing mutant derived from 15T- changes only half as much . Strain 15T- experiences a 2.4-fold change in doubling time across this temperature range, but doubling time in the mutant changes 3.3-fold.

Can J Microbiol, 1978 Oct, 24(10), 1250 - 2
Inhibitors of DNA synthesis cause excessive DNA synthesis in dnaA mutants of Escherichia coli K12; Heinonen J et al.; The relative rate of net DNA synthesis was stimulated when cells of dnaA mutants of Escherichia coli K12 were grown in the presence of low concentrations of DNA synthesis inhibitors . This led to a supernormal DNA/cell mass ratio . The excessive DNA was similar to the normal chromosomal DNA in size and stability in vivo . However, the cells did not divide but turned into long filaments . Excessive DNA synthesis in the presence of inhibitors of DNA synthesis was observed in the cultures of two independent dnaA mutants of E . coli, but dnaB and dnaC mutants behaved like the wild type in this respect.

Nucleic Acids Res, 1978 Oct, 5(10), 3871 - 9
Interaction of N-acetyl-phenylalanyl-tRNAPhe with 70S ribosomes of Escherichia coli; Odinzov VB et al.; The interaction of N--Acetyl--Phe--tRNA Phe with 70 S ribosomes is a reversible process in the absence as well as in the presence of messenger . The equilibrium binding constants of these interactions were measured at different magnesium concentrations and temperatures and thermodynamical quantities computed . The enthalpy of the formation of complexes with the P site of ribosomes is larger by 6,000 cal/mol in the presence of poly (U) than in the presence of poly (C) or in total absence of messenger . Free energy differences are rather small, the association constants differ less than one order of magnitude . The association constant of N--Acetyl--Phe--tRNA Phe with the A site of ribosomes is 30--50 times lower than with the P site even in the presence of poly (U).

Nucleic Acids Res, 1978 Oct, 5(10), 3831 - 42
Purification of potential 3' processing nucleases using synthetic tRNA precursors; Ghosh RK et al.; The synthetic tRNA precursors, tRNA-C-114C}U and tRNA-C-C-A-{14C}C-C, as well as poly (a) and diesterase-treated tRNA, have been used to identify and purify potential 3'processing nucleases . Four activities have been separated by this analysis; and three of them have been characterized . Two of the enzymes, which are well-separated on hydroxylapatite columns, act on poly(A), require K+ and Mg2+ for activity, and have molecular weights of about 90,000 . These activities have properties previously ascribed to RNase II . The third enzyme does not act on poly(A), requires Mg2+ for activity, and has a molecular weight of about 60,000 . It is identical to RNase D, previously characterized as an exonuclease acting on tRNAs with altered structure . Each of the enzymes can remove nucleotides from the tRNA precursor containing extra nucleotides beyond the 3'terminus, whereas they are relatively inactive with intact tRNA or tRNA-C-U . The greatest specificity was displayed by RNase D . The possibility that RNase D is a 3'processing nuclease is discussed.

Nucleic Acids Res, 1978 Oct, 5(10), 3821 - 9
Preparation of synthetic tRNA precursors with tRNA nucleotidyltransferase; Deutscher MP et al.; Rabbit liver tRNA nucleotidyltransferase can be used to substitute nucleotides within the -C-C-A sequence of tRNA or to add nucleotides following this sequence . These anomolous reactions of the enzyme have been used to prepare radioactively-labeled synthetic tRNA precursors which mimic the structure of the natural precursors . Under appropriate conditions synthetic precursors of defined structure can be made . In this paper we describe the synthesis of tRNA-C-{14C}U and tRNA-C-C-A-{14C}C-C, which are representative of tRNA precursors containing altered residues within the -C-C-A sequence or with extra residues following the normal 3'terminus . A variety of other possible precursors can also be prepared . These synthetic tRNA precursors have already proved useful for isolation of possible tRNA processing nucleases.

Nucleic Acids Res, 1978 Oct, 5(10), 3579 - 87
Small-angle X-ray titration of the complex formed between the ribosomal protein S4 and its 16S binding site, S4-RNA: a central core in the 30S subunit; Osterberg R et al.; X-ray scattering titrations at 21 degree C and in ribosomal reconstitution buffer indicate that the S4-RNA and the protein S4 from a 1:1 complex with a stability constant, log K approximately 6.5 . When the complex forms, there is only a limited change in the scattering curve indicating that S4-RNA essentially retains its conformation during the complex formation . The increase in the gyration radius as a result of the complex formation, delta R = 4 +/- 3 A, as well as the experimental scattering curve of the complex can be explained by models where the protein S4 is supposed to interact with the periphery of the S4-RNA.

Nucleic Acids Res, 1978 Oct, 5(10), 3503 - 13
RNA-RNA interactions in the binding site of protein L24 on 23S ribosomal RNA of Escherichia coli: 1 . Evidence for their occurrence between widely separated sequence regions; Sloof P et al.; Protein L24, from the Escherichia coli ribosome, protects a large region of 23S RNA against ribonuclease digestion . This protected RNA consists of a series of non-contiguous subfragments encompassing about 480 nucleotides at the 5' -end of 23S RNA (1) . The present work demonstrates that this RNA moiety remains intact, after removal of protein L24, indicating that the subfragments are maintained together by RNA-RNA interactions . Using a urea washing procedure, the weakly bound RNA subfragments were selectively removed leaving more strongly interacting subfragments that were identified, by gel electrophoresis and oligonucleotide fingerprinting, and shown to derive from widely separated sequence regions.

Gene, 1978 Oct, 4(2), 175 - 9
Conjugal transfer of cloning vectors derived from ColE1; Young IG et al.; The transfer properties of five cloning vectors derived from ColE1 were studied . Two of the vectors (pSF2124 and pGM706) behaved like wild type ColE1 in that they could be transferred efficiently in the presence of the conjugative plasmid F . The mobilization of the remaining three vectors (pMB9, PBR313 and pBR322) by F was barely detectable . The transfer defect in pBR313 and pBR322 could be complemented by ColK when R64drd11, but not F, was used as the conjugative plasmid . The transferred plasmids could be recovered unchanged from recipients . Conjugal transfer is a potentially useful technique for screening hybrid plasmids in low-risk cloning experiments involving poorly transformable strains.

Gene, 1978 Oct, 4(2), 153 - 66
The genes for 18S, 5.8S and 28S ribosomal RNA of Bombyx mori are organized into tandem repeats of uniform length; Manning RF et al.; The organization of the multiple genes for 18S, 5.8S and 28S rRNA in the genome of the silkworm, Bombyx mori was determined by restriction endonuclease digestion and Southern blot hybridization . The ribosomal genes (rDNA) are tandemly reiterated, with a uniform repeat length of 6.9 . 10(6) daltons . Each rDNA repeat has a single site for EcoRI, HindIII, HpaI and SmaI and each of these sites has been mapped with respect to the others and to the rRNA genes; each repeat consists of a transcribed region (6 . 10(6)daltons) containing the 18S, 5.8S and 28S rRNA genes (5' leads to 3') and also a small non-transcribed spacer (approximately 10(6) daltons) . Complete rDNA repeats were cloned using the vector RSF2124 and grown in Escherichia coli . Characterization of the rDNA plasmids confirmed the conclusions from studies of the total rDNA . The organization of B . mori rDNA is similar to that of other eukaryotes, except for the absence of heterogeneity in the rDNA repeat length; thus, there is neither variation in the length of the non-transcribed spacer nor the presence of inserts in a detectable portion of the rDNA . The utility of this map, and particularly of the rDNA plasmids, for detailed studies of rRNA transcription and processing is discussed.

Gene, 1978 Oct, 4(2), 121 - 36
Construction and characterization of new cloning vehicles . III . Derivatives of plasmid pBR322 carrying unique Eco RI sites for selection of Eco RI generated recombinant DNA molecules; Bolivar F; In vitro recombinant DNA techniques were used to construct two new cloning vehicles, pBR324 and pBR235 . These vectors, derived from plasmid pBR322, are relaxed replicating elements . Plasmid pBR324 carries the genes from pBR322 coding for resistance to the antibiotics ampicillin (Apr) and tetracycline (Tcr) and the colicin E1 structural and immunity genes derived from plasmid pMBI . Plasmid pBR325 carries the Apr and Tcr genes from pBR322 and the cloramphenicol resistance gene (Cmr) from phage P1Cm . In these plasmids the unique EcoRI restriction site present in the DNA molecule is located either in the colicin E1 structural gene (pBR324) or in the Cmr gene (pBR325) . These vectors were constructed in order to have a single EcoRI site located in the middle of a structural gene which when inactivated would allow, for the easy selection of plasmid recombinant DNA molecules . These plasmids permit the molecular cloning and easy selection of EcoRI, BamHI, HindIII, PstI, HincII, SalI, (XamI), Smal, (XmaI), BglII and DpnII restriction generated DNA molecules.

Gene, 1978 Oct, 4(2), 109 - 19
Insertion of the Tn3 transposon into the genome of the single-stranded DNA phage M13; Ray DS et al.; The transposable genetic element Tn3, which carries an ampicillin (Ap) resistance determinant, has been translocated from a ColE1-Apr plasmid, RSF2124, to the genome of the filamentous single-stranded DNA phage M13 . The site orientation of the inserted element has been determined for one such phage, M13::Tn3-15 . The insertion is within the intergenic space separating genes 2 and 4 and containing both the viral strand and complementary strand origins . The lengths of both the filamentous phage and the duplex replicative form (RF) DNA are 1.7--1.8 times those of M13 phage and replicative form DNA . Both plaque formation and transduction of sensitive cells to ampicillin resistance by M13::Tn3-15 are sensitive to purified antibodies to the M13 major coat protein.

Genetika, 1978 Oct, 14(10), 1838 - 41
{Mutagenic effect of the decay of 32p incorporated into mRNA}; Zakharov IA et al.; The transcription of Escherichia coli lactose operon was induced and the conditions for 32P maximal incorporation into mRNA which is synthesized on this operon were made . The complex between mRNA and DNA has been fixed . The DNA complementary strand has been damaged with the 32P desintegration . The induction of mutants uncapable of lactose utilization has been observed . It is shown that the number of such mutants in the experiments with 32P and with the inducer is twice as much as in the cheek experiments with 32P only.

Genetika, 1978 Oct, 14(10), 1687 - 95
{Regulation of RNA replication in RNA-containing bacteriphages . RNA synthesis in coat protein polar mutants}; Pumpen PP et al.; The synthesis of RNA by polar coat protein mutants f2sus3 and Qbetaam12 under suppressor (Escherichia coli S26R1E, Su+-1; H12R8a Su+-3) and non-suppressor (E . coli AB259; S26) conditions was examined . It was demonstrated that the synthesis of viral RNA under non-suppressor conditions in the presence of rifamycin produced the same gaussian pattern of rates as the synthesis of RNA by wild type phage or non-polar coat protein mutants . However, the total amount of RNA was decreased approximately 10-fold and the peak of RNA synthesis was displaced 7--10 min later . The number of infective centers was reduced also 10-fold indicating that a certain time-lapse was required to overcome the polarity of the parental RNA, this process being of single occurrence, exclusively on the parental RNA, but not on the progeny strains . As a consequence, it was concluded that the initiation of translation at the replicase cistron starts on the nascent RNA chains within the replicative complexes and not on the fully-synthesized templates with their complete secondary structure . The data obtained are not in contradiction with the hypothesis concerning the role of the repressor complex II (replicase-RNA) to slow down the synthesis of replicase and RNA in the coat protein mutants . The polarity can not be responsible probably for the blocking of the replicase cistron on the nascent chain following the block of coat protein cistron . Therefore, it appears appropriate to assume the existence of two binding sites for the replicase as repressor which is in keeping with the conclusions of Weissmann and co-workers.

Bull Environ Contam Toxicol, 1978 Oct, 20(4), 433 - 7
Alterations of the antibody response following in utero exposure to diethylstilbestrol; Luster MI et al.; The antibody response to SRBC and E . coli 0127 lipopolysaccharide were determined in offspring from mice exposed in utero to diethylstilbestrol . The antibody response to SRBC, a T-cell dependent antigen, was similar in control and exposed animals . In contrast, the LPS antibody response was suppressed in treated females and enhanced in treated males . These studies indicated that in utero exposure to DES alters the humoral immune system to T-independent antigens.

Acta Physiol Scand, 1978 Oct, 104(2), 167 - 74
Suppresion of autonomic postganglionic discharges by pentobarbital in dogs, with or without endotoxemia; Halinen MO et al.; Initial effects of pentobarbital (8 mg/kg) on autonomic efferent and afferent discharge rates were studied in 26 dogs under morphine-chloralose anesthesia . Half of the dogs were given endotoxin E . coli (1 mg/kg) before pentobarbital . The postganglionic cervical vagal efferentation of all the dogs decreased as did the postganglionic cardiac sympathetic efferentation . The heart rate of the dogs given endotoxin decreased, while an increase in heart rate with abolition of respiratory arrhythmia, was observed in dogs without endotoxin . The aortic pressure of the former dogs dropped while it fell only slightly in the latter ones . The aortic arch baroreceptor activity decreased while the changes of left atrial B-type receptor activity were not significant . The changes of the left atrial and central venous pressures were slight but those of the pulmonary arterial pressure generally paralleled the changes in the aortic pressure . Pentobarbital, accordingly, seems to exert both sympatholytic and vagolytic effects . These explain the heart rate changes, as well as the impaired cardiac contractility it evokes . The obvious impairment of cardiovascular control mechanisms by pentobarbital should be seriously considered in investigations into the cardiovascular control.

J Bacteriol, 1978 Oct, 136(1), 5 - 9
Proline transport carrier-defective mutants of Escherichia coli K-12: properties and mapping; Motojima K et al.; A series of mutants of Escherichia coli K-12 requiring a high concentration of L-proline for growth were isolated from a proline auxotroph strain, JE2133 . Genetic studies of the mutants, PT19, PT21, and PT22, showed that all the mutations (proT) were point mutations, and these were mapped at 82 min on the E . coli genetic map . Intact cells and cytoplasmic membrane vesicles of these mutants were specifically defective in L-proline transport activity . Strain PT21 had no detectable activity of the L-proline transport carrier at all, and strains PT19 and PT22 had only 1/35 and 1/70, respectively, of the transport activity of the parental strain . The mutants were also shown to have a defect in proline-binding function of the carrier by measuring specific binding of proline to sonically disrupted membranes . These results indicate that the gene proT determines the function of proline carrier in the cytoplasmic membrane.

J Bacteriol, 1978 Oct, 136(1), 460 - 2
Enchancement of nitrosoguanidine mutagenesis by chloramphenicol in Escherichia coli K-12; Sklar R; N-methyl-N'-nitro-N-nitrosoguanidine-induced mutagenesis in E . coli K-12 can be enchanced up to 50-fold by the addition of chloramphenicol with minimal effect on survival . Chloramphenicol does not produce the expected proportionate increase in closely linked double mutations.

J Bacteriol, 1978 Oct, 136(1), 455 - 9
The F plasmid may cosegregrate with either DNA strand of the Escherichia coli chromosome; Leibowitz PJ et al.; A stable association exists between the plasmid Flac and one of the polynucleotide strands of the bacterial chromosome . This polynucleotide strand was isolated and tested for uniqueness by DNA-DNA hybridization analysis . The association was found to involve either bacterial DNA strand.

J Bacteriol, 1978 Oct, 136(1), 444 - 8
Dimer excision and repair replication patch size in recL152 mutant of Escherichia coli K-12; Rothman RH; Dimers are excised slowly in a recL152 mutant . This observation is not an artifact of altered DNA degradation because degradation is the same in recL+ and recL strains . The repair patch size was measured by the bromodeoxyuridine-313 nm radiation photolysis technique . In the recL+ strain, the average patch size was found to be about 30 nucleotides in length, but in the recL mutant, it was about 360.

J Bacteriol, 1978 Oct, 136(1), 429 - 32
Comparison of ribosomes from Coxiella burnetii and Escherichia coli by gel electrophoresis, protein synthesis, and immunological techniques; Baca OG; Ribosomes and postribiosomal supernatant fluid (S-100) were isolated from Coxiella burnetii . The ribosomes functioned in polyuridylic acid-directed polyphenylalanine synthesis in the presence of S-100 from either C . burnetii or Escherichia coli . C . burnetii S-100 promoted translation with E . coli ribosomes . Antisera against E . coli elongation factor G and ribosomal proteins L7/L12 cross-reacted with rickettsial S-100 and ribosomes, respectively . Ribosomal proteins were analyzed by two-dimensional gel electrophoresis.

J Bacteriol, 1978 Oct, 136(1), 419 - 22
Absence of DNA sequences homologous to transposable element Tn5 (Kan) in the chromosome of Escherichia coli K-12; Berg DE et al.; The DNA hybridization procedure of Southern has been used to search for homology between the transposable kanamycin resistance determinant Tn5 and sequences in the chromosome of Escherichia coli K-12 . No homology was detected under conditions in which a segment homologous to 5% or more of the 5,300-base pair Tn5 element would have been seen.

J Bacteriol, 1978 Oct, 136(1), 369 - 80
Cloned DNA fragment specifying major outer membrane protein a in Escherichia coli K-12; Gayda RC et al.; Plasmid pMC44 is a recombinant plasmid that contains a 2-megadalton EcoRI fragment of Escherichia coli K-12 DNA joined to the cloning vehicle, pSC101 . The polypeptides specified by plasmid pMC44 were identified and compared with those specified by pSC101 to determine those that are unique to pMC44 . Three polypeptides specified by plasmid pMC44 were localized in the cell envelope fraction of minicells: a Sarkosyl-insoluble outer membrane polypeptide (designated M2), specified by the cloned 2-megadalton DNA fragment, and two Sarkosyl-soluble membrane polypeptides specified by the cloning plasmid pSC101 . Bacteria containing plasmid pMC44 synthesized quantities of M2 approximately equal to the most abundant E . coli K-12 outer membrane protein . Evidence is presented that outer membrane polypeptide M2, specified by the recombinant plasmid pMC44, is the normal E . coli outer membrane protein designated protein a by Lugtenberg and 3b by Schnaitman.

J Bacteriol, 1978 Oct, 136(1), 280 - 5
Cell envelope and shape of Escherichia coli: multiple mutants missing the outer membrane lipoprotein and other major outer membrane proteins; Sonntag I et al.; Starting with an Escherichia coli strain missing the outer membrane lipoprotein, multiple mutants were constructed than in addition to this defect miss the outer membrane proteins II, Ia and Ib, or Ia, Ib, and II . In contrast to all single mutants or strains missing the lipoprotein and polypeptides Ia and Ib, drastic influences on the integrity of the outer membrane and cell morphology were observed in mutants without lipoprotein and protein II . Such strains exhibited spherical morphology . They required increased concentrations of electrolytes for optimal growth, and Mg2+ or Ca2+ were the most efficient . These mutants were sensitive to hydrophobic antibiotics and detergents . Electron microscopy revealed abundant blebbing of the outer membrane, and it could clearly be seen that the murein layer was no longer associated with the outer membrane.

J Bacteriol, 1978 Oct, 136(1), 179 - 90
Chromosome replication during the division cycle in slowly growing, steady-state cultures of three Escherichia coli B/r strains; Kubitschek HE et al.; The period of DNA synthesis C during the cell cycle was determined over a broad range of generation times in slowly growing, steady-state batch cultures in the exponential phase and in chemostat cultures of three strains of Escherichia coli, strains B/r A, B/r K, and B/r TT, utilizing measurements of average amounts of DNA per cell and cell survival after radioactive decay of 125I incorporated into the DNA of synthesizing cells . At each growth rate, values for cell survival and for C periods were the same within experimental errors for the three strains . The length of the DNA synthesis period increased linearly with generation (doubling) time T of the culture and approached a limiting value of C = 0.36T at very long generation times . In very slowly growing cultures, DNA replication was limited almost entirely to the final third of the cell cycle . D periods, between termination of DNA replication and cell division, were found to be relatively short at all growth rates for each strain . Average amounts of DNA per cell measured in slowly growing cultures of strains B/r A and B/r TT were indistinguishable from results for strain B/r K at the same growth rates . Amounts of DNA per cell calculated from the cell survival values alone are completely consistent with the measured DNA per cell.

J Bacteriol, 1978 Oct, 136(1), 168 - 74
Genetic separation of high- and low-affinity transport systems for branched-chain amino acids in Escherichia coli K-12; Anderson JJ et al.; The Escherichia coli K-12 mutant strain AE4107 (livH::Mu) is defective in the high-affinity binding protein-mediated uptake system for L-leucine, L-valine, and L-isoleucine (LIV-I) . We have used this strain to produce mutations in the residual LIV-II membrane-bound branched-chain amino acid uptake system . Mutants selected for their inability to utilize exogenous L-leucine were found to be defective in the LIV-II system and fell into two classes . One class, represented by strain AE410709 (livP9), showed a complete loss of saturable uptake for L-leucine, L-valine, and L-isoleucine up to 50 muM, and a second class, represented by strain AE4017012 (liv-12), showed a residual component of saturable leucine uptake with increased Km . These mutations, livP9 and liv-12, were closely linked and mapped in the 74 to 78 min region of the E . coli genetic map . Strains constructed so that they lacked both LIV-I and LIV-II transport systems excreted leucine . Strains of the genotype livH+ livP were found to have normal high-affinity binding protein-mediated transport (LIV-I and leucine specific), whereas the low-affinity (LIV-II) transport was completely missing . We concluded from these studies that the high-affinity binding protein-mediated transport systems (LIV-I and leucine specific) can operate independently of the membrane-bound LIV-II system.

J Bacteriol, 1978 Oct, 136(1), 136 - 41
Evidence for an intermediate in quinolinate biosynthesis in Escherichia coli; Wicks FD et al.; Evidence for the formation of an unstable intermediate in the synthesis of quinolinate from aspartate and dihydroxyacetone phosphate by Escherichia coli was obtained using toluenized cells of nadA and nadB mutants of this organism and partially purified A and B proteins in dialysis and membrane cone experiments . The results of these experiments indicate that the nadB gene product forms an unstable compound from aspartate in the presence of flavine adenine dinucleotide, and that this compound is then condensed with dihydroxyacetone phosphate to form quinolinate in a reaction catalyzed by the nadA gene product.

J Bacteriol, 1978 Oct, 136(1), 125 - 30
Reduction of postreplication DNA repair in two Escherichia coli mutants with temperature-sensitive polymerase III activity: implications for the postreplication repair pathway; Johnson RC; Daughter strand gaps are secondary lesions caused by interrupted DNA synthesis in the proximity of UV-induced pyrimidine dimers . The relative roles of DNA recombination and de novo DNA synthesis in filling such gaps have not been clarified, although both are required for complete closure . In this study, the Escherichia coli E486 and E511 dnaE(Ts) mutants, in which DNA polymerase I but not DNA polymerase III is active at 43 degrees C, were examined . Both mutants demonstrated reduced gap closure in comparison with the progenitor strain at the nonpermissive temperature . These results and those of previous studies support the hypothesis that both DNA polymerase I and DNA polymerase III contribute to gap closure, suggesting a cooperative effort in the repair of each gap . Benzoylated, naphthoylated diethylaminoethyl-cellulose chromatography analysis for persistence of single-strand DNA in the absence of DNA polymerase III activity suggested that de novo DNA synthesis initiates the filling of daughter strand gaps.

J Bacteriol, 1978 Oct, 136(1), 117 - 24
Suppressors of a genetic regulatory mutation affecting isoleucine-valine biosynthesis in Escherichia coli K-12; Hahn JE et al.; Escherichia coli K-12 mutant PS187 carries a mutation, ilvA538, in the structural gene for the biosynthetic L-threonine deaminase that leads to a leucine-sensitive growth phenotype, an isoleucine- and leucine-hypersensitive L-threonine deaminase, and pleiotropic effects resulting in abnormally low and invariant expression of some of the isoleucine-valine biosynthetic enzymes . Fifty-eight derivatives of strain PS187 were isolated as resistant to growth inhibition by leucine, by valine, or by valine plus glycly-valine and were biochemically, genetically, and physiologically characterized . All of these derivatives produced the feedback-hypersensitive L-threonine deaminase, and thus presumably possess the ilvA538 allele of the parent strain . Elevated synthesis of L-threonine deaminase was observed in 41 of the 58 isolates . Among 18 strains analyzed genetically, only those with mutations linked to the ilv gene clusters at 83 min produced elevated levels of L-threonine deaminase . One of the strains, MSR91, isolated as resistant to valine plus glycyl-valine, was chosen for more detailed study . The locus in strain MSR91 conferring resistance was located in four factor crosses between ilvE and rbs, and is in or near the ilvO gene postulated to be a site controlling the expression of the ilvEDA genes . Synthesis of the ilvEDA gene products in strain MSR91 is constitutive and derepressed approximately 200-fold relative to the parent strain, indicating that the genetic regulatory effects of the ilvA538 allele have been suppressed . Strain MSR91 should be suitable for use in purification of the ilvA538 gene product, since enzyme synthesis is fully derepressed and the suppressor mutation is clearly not located within the ilvA gene.

J Bacteriol, 1978 Oct, 136(1), 1 - 4
Role of the Escherichia coli aromatic amino acid aminotransferase in leucine biosynthesis; Powell JT et al.; Strains of Escherichia coli that lack the branched-chain amino acid amino-transferase because of mutations in the ilvE gene had no growth requirement for leucine when the cells contained the aromatic amino acid aminotransferase that is the product of the tyrB gene . The presence of leucine increased the generation time of these cells and decreased the specific activity of the aromatic amino acid aminotransferase . It is concluded that this enzyme functions efficiently in leucine biosynthesis and can be repressed by leucine as well as by tyrosine.

Eur J Biochem, 1978 Oct, 90(2), 347 - 58
Response of the pyrimidine pathway of Escherichia coli K 12 to exogenous adenine and uracil; Christopherson RI et al.; The effect of exogenous adenine or uracil upon the de novo pathway for synthesis of pyrimidine nucleotides in Escherichia coli K12 was investigated . Parameters studied were levels of the enzymes carbamoyl phosphate synthase (EC 2.7.2.9), aspartate carbamoyltransferase (EC 2.1.3.2) and orotate phosphoribosyltransferase (EC 2.4.2.10) and the intermediates carbamoyl phosphate, aspartate and orotate, together with the contributions of exogenous uracil and aspartate to intracellular pyrimidine nucleotide . Taken with earlier data {Bagnara, A.S . & Finch, L . R . (1974) Eur . J . Biochem- 41, 421--430} on contents of UTP, CTP and 5-phosphoribosyl 1-diphosphate in cultures of this strain after the addition of adenine or uracil, the results obtained provide new insights into the regulatory mechanisms operating on the pathway in vivo . These insights enable evaluation of the contributions of such factors as limitation for a substrate, feed-back allosteric control by end products and enzyme repression/depression mechanisms . The evidence presented indicates that depressed levels of orotate phosphoribosyltransferase in E . coli K12 result in the wasteful ultilization of asparatate for excess synthesis of pyrimidine nucleotide precursors during balanced growth of the strain in minimal medium . Exogenous adenine increases the excessive accumulation of these precursors by lowering the intracellular content of 5-phosphoribosyl 1-diphosphate (Bagnara and Finch, 1974) . This causes a decrease in the conversion of orotate to orotidine 5'-monophosphate, thus lowering the utilization or orotate and its precursors for synthesis of pyrimidine nucleotides . Further, since the contents of these nucleotide end products are thereby decreased (Bagnara nad Finch, 1974), theri feed-back on the early steps in the pathway is diminished and the production of the precursors is increased . It is postulated that growth of E . coli K12 under these conditions is limited by a compound that is metabolically related to precursors to aspartate.

Eur J Biochem, 1978 Oct, 90(2), 319 - 23
Dimer state of protein L7/L12 and EF-G-dependent reactions of ribosomes; Koteliansky VE et al.; A number of different monomer and dimer derivatives of protein L7/L12 has been studied in EF-G-dependent reactions on the ribosome . It has been shown that only dimer derivatives of protein L7/L12 are able to interact with the ribosome . This means that it is the dimer forms of protein L7/L12 that are present in the functionally active ribosome . It is likely that the N-terminal sequence of protein L7/L12 is responsible for dimerization of the protein in solution and at the same time contributes mainly to the interaction of the protein L7/L12 dimer with the ribosome . The results obtained suggest that there are four copies of protein L7/L12 in the translating ribosome.

Eur J Biochem, 1978 Oct, 90(2), 313 - 8
Studies on the structure of protein L7/L12 from Escherichia coli ribosomes; Gudkov AT et al.; Circular dichroism, infrared and proton magnetic resonance spectroscopy as well as microcalorimetry methods were used to investigate the intact proteins L7/L12 in solution and their different derivatives (L7 with oxidized residues of methionine, fragments 27--120, 1--73 and 74--120)- On the basis of the data obtained the following conclusions have been drawn: (a) there is no beta structure in the protein L7, (B) the N-terminal region of L7 forms a long alpha helix (c) the Phe-30 residue within the N-terminal region of L7 takes part in the dimerization, (d) the C-terminal of L7 is globular and (e) the Phe-54 residue is included in the hydrophobic core of the globular C-terminal region.

Eur J Biochem, 1978 Oct, 90(2), 309 - 12
The N-terminal sequence protein of L7/L 12 is responsible for its dimerization; Gudkov AT et al.; Ultracentrifuge studies of intact protein L7/L12, of its fragments 27--120, 1--74 and 74--120 and of protein L7/L12 with oxidized methionine residues, indicate that the N-terminal sequence of the protein L7/L12 is responsible for its dimerization . The symmetry model of the dimer is discussed.

Eur J Biochem, 1978 Oct, 90(2), 271 - 81
On the mechanism of assembly of the aspartate transcarbamoylase from Escherichia coli; Chan WW; The mechanism of subunit assembly of aspartate transcarbamoylase from Escherichia coli was studied by following the kinetics of reassociation . The isolated trimetric catalytic subunit (c3) and dimeric regulatory subunit (r2) were mixed together and formation of the dodecameric native enzyme (c6r6) was monitored by measuring changes in activity . Under appropriate conditions the reassociation was second order with respect to the c3 concentration and the effects of varying r2 concentration on the second-order rate constant were examined . An optimum R2 concentration of about 0.07 micrometer was observed . A scheme of the assembly pathways is proposed and is based on the reversible formation of c3r2n (n = 0, 1, 2 or 3) as intermediates . Various combinations of two such c3r2n species are considered as possible rate-limiting steps . This model yields an expression which relates the experimentally determined (overall) second-order rate constant to the equilibrium constant (Kd) governing the formation of c3r2n, the r2 concentration, and four coefficients which reflect the contribution of different types of assembly processes . Using previously determined values of Kd, the above expression for each r2 concentration reduces to a linear equation with four unknowns . The experimental data were subjected to multiple linear-regression analysis and values for the four coefficients were found which gave an excellent fit . Our results show that reassociation of the subunits is a fast bimolecular reaction with rate constants in excess of 10(6) M-1 s-1 . Our analysis also suggests that interactions involving a total of more than three r2 subunits (e.g . the combination of c3r2 with c3r6) might contribute significantly to the overall assembly . The influence of various ligands on the reassociation rate profile was also studied . All ligands examined were partially inhibitory to the formation of native enzyme . The effects of substrates were similar to those of CTP whereas the effects of ATP were substantially different . These observations can be readily interpreted by postulating different conformational changes induced by the ligands . These changes should alter the relative orientation of the subunit contacts which must be formed in the reassociation process . The interpretation is consistent with our previous model of the allosteric mechanism.

Z Gastroenterol, 1978 Oct, 16(10), 645 - 51
{Effect of portocaval shunt and arterialization of the liver on antibodies to Escherichia coli in patients with cirrhosis of the liver (author's transl)}; Schneider K et al.; The effect of a portocaval shunt with and without portal arterialization of the liver on serum immunoglobulin concentrations and on the incidence of antibodies to 8 different serotypes of Escherichia coli was studied in 29 patients with cirrhosis of the liver . Compared with healthy controls, the serum concentrations of IgG, IgA and IgM were significantly elevated in cirrhotic patients . No difference in immunoglobulin concentrations could be observed between shunted and arterialized cirrhotics . The incidence of E . coli antibodies was significantly higher in patients with cirrhosis of the liver, showing a further increase in patients with portocaval shunt operations . Portal arterialization of the liver after portocaval shunting did prevent this additional increase, presumably by restoring the antigen clearing capacity of the cirrhotic liver, thus avoiding an additional stimulation of the antigen response after the portocaval shunt . The quantitative contribution of E . coli antibodies to the hyperimmunoglobulinemia of patients with cirrhosis of the liver seems to be of little significance . The results of this study underline the significance of the portal hepatic blood flow for the function of the reticulo-endothelial system of the liver.

Mech Ageing Dev, 1978 Oct, 8(4), 285 - 97
Increase in the ratio of 18S RNA to 28S RNA in the cytoplasm of mouse tissues during aging; Mori N et al.; The possibility of alterations in cytoplasmic RNA in mouse liver, kidney and brain during aging was investigated . The cytoplasmic RNAs in these organs gave similar profiles of optical density at 260 nm with three major peaks at 28S, 18S and 4S on sucrose gradient centrifugation . However, the ratio of the amounts of 18S and 28S RNA increased significantly with age in the brain and liver . The polyacrylamide gel electrophoretic patterns of extracts of the three tissues under both native and denaturing conditions were nearly identical regardless of the age of the animals . Since most of the minor components separated on gels were probably in vivo degradation products of ribosomal RNA, these results suggest that the extent of apparent and hidden breaks in ribosomal RNA does not change during aging.

Carbohydr Res, 1978 Oct, 66, 213 - 23
Studies on some biologically active dextrans; Preobrazhenskaya ME et al.; The relationship between the structures of six native dextrans and their effects on nonspecific resistance to infection (n.s.r.i.) in mice and also anticomplementary activity has been studied . The data obtained showed that the n.s.r.i . activity of dextrans generally increased with increase of extent of branching, but no direct correlation between these two factors was found . Data on exodextranase-catalyzed hydrolysis of dextrans suggest that the length of the outer chains may be important for the n.s.r.i . activity of the dextrans . Dextrans characterized by a significant extent of branching were anticomplementary, but no relationship between extent of branching and anticomplementary activity was observed.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 5030 - 3
Does 3'-terminal poly(A) stabilize human fibroblast interferon mRNA in oocytes of Xenopus laevis?
Sehgal PB, Soreq H, Tamm I.
Polynucleotide phosphorylase (polyribonucleotide:orthophosphate nucleotidyltransferase, EC 2.7.7.8) purified from Escherichia coli was used enzymatically to deadenylate polyadenylated human fibroblast interferon mRNA preparations obtained from human diploid fibroblasts (FS-4 strain) induced by poly(I)-poly(C) (20 microgram/ml) in the presence of cycloheximide (50 microgram/ml, 4 hr) . Both the polyadenylated and the deadenylated interferon mRNA preparations were translated into biologically active human interferon when injected into oocytes of Xenopus laevis . In the oocytes the functional stability of deadenylated interferon mRNA was indistinguishable from that of polyadenylated interferon mRNA.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4940 - 3
Mechanism of phage Mu-1 integration: nalidixic acid treatment causes clustering of Mu-1-induced mutations near replication origin; Paolozzi L et al.; Frequencies of Mu-1-induced mutants of Escherichia coli have been compared under two different experimental conditions: cells in exponential growth and the same cells treated with nalidixic acid . The average of values obtained from the nalidixic acid-treated culture is 3 times higher than that obtained from the control . Individual ratios of the frequency of mutants in the two cultures yield decreasing values from 6 to 1, starting from the point of origin of DNA replication to the termini of DNA replication . These results are compatible with the idea that Mu-1 integrates at the replication fork.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4784 - 7
Phosphate (oxygen)-water exchange reaction catalyzed by human prostatic acid phosphatase; Van Etten RL et al.; Conclusive evidence is presented that an acid phosphatase catalyzes phosphate (oxygen)-water exchange . Studies conducted with human prostatic acid phosphatase by two independent methods have established that, despite earlier reports to the contrary, the enzyme catalyzes an exchange reaction between oxygen atoms of phosphate ion and of water . Kinetic data were obtained both by chemical conversion to trimethyl phosphate followed by mass spectroscopy and by a totally independent method involving 31P isotope shift nuclear magnetic resonance spectroscopy . Analysis showed that the enzyme catalyzes the exchange in a random, noncoupled process . If any coupled exchange occurs, it must represent less than 10% of the total . By mass spectral analysis, catalytic rate constants kcat = 0.14 sec-1 (4 degrees) and 1.8 sec-1 (37.5 degrees) were obtained . By 31P nuclear magnetic resonance kcat = 1.6 sec-1 (31 degrees) was obtained . The energy of activation for the exchange reaction is approximately 13kcal mol-1 . The kcat value for exchange is about 10-fold greater than that observed with Escherichia coli alkaline phosphatase.

Zh Mikrobiol Epidemiol Immunobiol, 1978 Oct, (10), 41 - 5
{Action of cyclic adenosine monophosphate on the spleen antibody--forming cells of rabbits immunized with Escherichia coli}; Dzheksenbaev OSh et al.; Cyclic adenosine monophosphate (cAMP) parenterally injected to rabbits (immunized intraperitoneally with thymus-independent antigen of killed E . coli 0127/545) during January--April inhibited production of antibody-forming cells (AFC) in the spleen of these animals, and during May--June it increased the AFC count . Both the stimulating and inhibitory effect of cAMP was associated with the administration of the same doses of 25--250 microgram/kg . The nature of the cAMP effect on the production of the AFC depends on the initial immune response level . At the maximum immune response and in the absence of the dose-effect dependence cAMP inhibited the antibody formation, but when the immunological reaction was below the maximal level and in the presence of the dose-effect relationship cAMP increased the AFC production.

Biochem J, 1978 Oct 1, 175(1), 189 - 92
Intrasubunit nucleotide binding in ribonucleic acid polymerase; Malcolm AD et al.; 1 . Periodate oxidation of the ribose ring was used to synthesize derivatives of nucleoside triphosphates . 2 . These oxidized nucleoside triphosphates . 2 . These oxidized nucleoside triphosphates are competitive inhibitors of RNA polymerase . 3 . On incubation, together with NaBH4, these oxidized labelled nucleotides are covalently bound to Escherichia coli RNA polymerase . 4 . Nucleoside triphosphate substrates decrease the extent of labelling . 5 . A lysine residue in an alpha-subunit is labelled . 6 . The significance of these results in relation to the location of the nucleotide-binding site is discussed.

J Infect Dis, 1978 Oct, 138(4), 437 - 44
Enhancement of neutrophil chemotaxis and alteration of levels of cellular cyclic nucleotides by levamisole; Hogan NA et al.; Levamisole, an antihelminthic agent reported to enhance nonspecifically various parameters of the immune response, was examined for its effect on chemotaxis of human neutrophils and on levels of cellular cyclic nucleotides . This agent was found, in most instances, to enhance chemotactic responses of neutrophils to a bacterial chemotactic factor derived from Escherichia coli . At similar concentrations, levamisole produced increases in levels of guanosine 3':5'-cyclic phosphate in neutrophils . In contrast, a decrease in concentrations of adenosine 3':5'-cyclic phosphate was observed when neutrophils were incubated with levamisole . Neutrophil chemotaxis, with and without the addition of levamisole, was assessed in 10 patients with recurrent infections . The illnesses of these patients included Job's syndrome, Wiskott-Aldrich syndrome, eczema with an increased level of IgE and recurrent abscesses, chronic mucocutaneous candidiasis, and diabetes mellitus . Levamisole significantly enhanced chemotaxis of polymorphonuclear leukocytes from these patients . Levamisole appears to have a profound effect on chemotactic responses of neutrophils which probably results from alterations in cellular cyclic nucleotide levels . Levamisole may prove to be useful therapeutically in certain patients with defective neutrophil chemotaxis.

J Bacteriol, 1978 Oct, 136(1), 96 - 103
Role of the dsdC activator in regulation of D-serine deaminase synthesis; Heincz MC et al.; The activator of the D-serine deaminase operon, the product of the dsdC gene, has been partially purified . It is reasonably stable to routine purification procedures in the presence of its ligand D-serine, but not in its absence . It loses activity upon dialysis in amino acid-free buffer, but activity is completely restored upon readdition of D-serine . It apparently functions purely as an activator, no repressor function could be demonstrated at suboptimal D-serine concentration . It is a transcriptional control element . The time required for in vitro transcription of D-serine deaminase mRNA, nearly 4 min, is similar to that for beta-galactosidase . Since the beta-galactosidase monomer is a much protein, this is surprisingly long.

J Bacteriol, 1978 Oct, 136(1), 104 - 10
Role of small molecules in regulation of D-serine deaminase synthesis; Heincz MC et al.; Cyclic AMP is required for optimal synthesis of D-serine deaminase synthesis from dsdO+ templates and for optimal hyperinducible synthesis from low constitutive dsdO templates both in vitro and in vivo . Neither D-serine, cyclic AMP, nor dsdC activator has an effect on expression of a high constitutive dsdO template . The synthesis of the dsdC activator itself in vitro is independent of cyclic AMP . Guanosine tetraphosphate does not have a significant effect on in vitro D-serine deaminase synthesis from dsdO+ or dsdO templates . A previously described class of dsdO mutants showing partial catabolite sensitivity of constitutive D-serine deaminase synthesis proved to be low dsdO types . They all contain a low constitutive dsdC mutation; the two effects are additive with regard to level of constitutivity, but only that portion of synthesis attributable to the dsdC mutation is cyclic AMP dependent.

J Virol, 1978 Oct, 28(1), 154 - 70
Cell-free synthesis of simian virus 40 T-antigens; Paucha E et al.; Polyacrylamide gel electrophoresis and tryptic peptide fingerprint analysis of the proteins made in a cell-free system derived from L-cells and immunoprecipitated with simian virus 40 (SV40) anti-T serum demonstrated that both SV40 large-T and small-T antigens are synthesized in vitro in response to mRNA isolated from productively infected CV1 CELLS . Sucrose density centrifugation in gradients containing 85% formamide showed that the mRNA's for both forms of T-antigen sediment at about 17.5S, with the mRNA for small-t sedimenting marginally, but reproducibly, ahead of the mRNA for large-T . Hybridization experiments using restriction endonuclease fragments Hae III-E and Hind II/III-B showed that all fractions active in the cell-free synthesis of both forms of T-antigen hybridized equally to both fragments . This suggests that the mRNA's for SV40 T-antigens are at least partly virus coded and that the bulk of the early SV40 mRNA contains sequence information from both ends of the early region . The data are consistent with the suggestion that the large-T mRNA is spliced . SV40 complementary RNA (the product of transcription of SV40 DNA using Escherichia coli RNA polymerase) was also translated in the L-cell system and gave two families of polypeptides which specifically immunoprecipitate with anti-T serum . One family (the small-t family) includes a polypeptide indistinguishable by gel electrophoresis and tryptic peptide fingerprinting from small-t isolated from cells . The other family (the 60K family) has a major component with molecular weight approximately 60,000 and includes other polypeptides with molecular weights ranging from approximately 14,000 to about 70,000 . The 60K family has petides in common with large-T but not with small-T . Together, the peptides of the small-t and 60K families account for virtually all of the methionine peptides of SV40 large-T . We conclude from these results (i) that small-t is probably entirely, and large-T at least predominantly, virus coded; (ii) that the small-t and 60K families represent the translation products of two different portions of the early region of SV40 DNA (approximately 0.65 to 0.55 map units and 0.54 to 0.17 map units); and (iii) that although most, if not all, of the large-T and small-t peptides are present in the cell-free product, some feature of sequence arrangement of SV40 complementary RNA prevents the translation of full-length large-T and results instead in the synthesis of fragments . We suggest that the absence of a splice in the complementary RNA is responsible for this result.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4828 - 32
Interaction of RNA polymerase and rho in transcription termination: coupled ATPase; Das A et al.; We have previously described temperature sensitive rho mutants of Escherichia coli (e.g., rho15) that are defective in transcription termination at various signals, including an IS2 DNA insertion in the gal operon {Das, A., Court, D . & Adhya, S . (1976) Proc . Natl . Acad . Sci . USA, 73, 1959-1963} . In this paper, we report the isolation of mutants altered in the beta subunit of RNA polymerase (a class of Rifampicin-resistant mutants), which restore gal IS2 polarity in the rho 15 strain . It has been shown that one of these suppressor RNA polymerases (rpoB101) requires rho to terminate transcription of phage lambda mRNA . In contrast to the wild type RNA polymerase, the suppressor RNA polymerase also terminates lambda mRNA transcription in the presence of rho15 protein . We have isolated new rho mutants (e.g., rho112) that are defective in transcription termination in the rpoB101 strain . These results strongly support the notion that rho and RNA polymerase interact functionally during transcription termination . We have shown that rho15 catalyzes ATP hydrolysis during transcription with rpoB101 RNA polymerase, but not with wild-type RNA polymerase . Because rho 15 protein hydrolyzes ATP in the presence of free RNA, we suggest that rho may recognize the 3'-OH end of RNA . During transcription, this recognition involves an interaction with RNA polymerase, resulting in the displacement of the polymerase and the release of the nascent mRNA.

Lab Anim, 1978 Oct, 12(4), 223 - 6
Colonization resistance of the digestive tract and gastrointestinal transit time in SPF mice; Koopman JP et al.; The gastro-intestinal colonization resistance to Escherichia coli was assessed in individual CBA/Rij, C3H/StZ and Swiss/Cpb:SE mice . Gastro-intestinal transit time was determined by feeding small steel balls and x-ray examination of sequentially collected faeces . No correlation was found between transit times measured on 3 subsequent days, nor between them and colonization resistance.

Zh Mikrobiol Epidemiol Immunobiol, 1978 Oct, (10), 61 - 6
{New indications for the participation of group P plasmids R in the transfer of chromosomal genes in intergenera crosses}; Minina TS et al.; Use of E . coli strains with phenotypes Rec+ and Rec- asrecipients in intergenera crosses confirmed the supposition put forward by the authors formerly that new chromosomal markers in transconjugantes originated due to Psuedomonas aeruginosa . These chromosomal markers were transferred together with plasmid R conditioning the conjugation, and maintained without being built-into E . coli chromosome . Between the arg+ marker and the plasmid R18 there existed labile physical connection demonstrable only under definite conditions of recombinant selection.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4824 - 7
beta-Galactosidase chimeras: primary structure of a lac repressor-beta-galactosidase protein; Brake AJ et al.; A protein possessing both lac repressor and beta-galactosidase activities in a single polypeptide of about 155,000 daltons was purified from a deletion mutant of Escherichia coli in which the lacI and Z genes are fused . A 77-residue cyanogen bromide peptide containing the fusion joint was isolated . A radioimmunoassay with an antibody prepared against CNBr2 (residues 3-92) of beta-galactosidase was used to monitor its purification . The sequence of the joining peptide was determined by analysis of tryptic peptides and by automatic sequencer analysis . The site of joining is from residue 355 of lac repressor to residue 24 of beta-galactosidase (or 356 to 25), indicating that the last 4 residues at the carboxyl terminus of lac repressor and the first 23 residues at the amino terminus of beta-galactosidase are not essential for the activities of these two proteins . The exact site of the fusion is not known because lac repressor residue 356 and beta-galactosidase residue 24 are both leucine residues . Examination of the nucleotide sequences around the two end points of the deletion revealed a homology of 9 identities in a stretch of 11 base pairs.

Surg Gynecol Obstet, 1978 Oct, 147(4), 545 - 57
Escherichia coli shock in the baboon and the response to adrenocorticosteroid treatment; Hinshaw LB et al.; Results of recent studies from this laboratory have demonstrated that methylprednisolone sodium succinate increases the survival rate of dogs given LD100 Escherichia coli endotoxin . This study was undertaken to determine the effects of methylprednisolone on the baboon infused with live Escherichia coli organisms . Awake baboons were paired by infusing intravenously comparable doses of Escherichia coli during a five hour period . Baboons given methylprednisolone received bolus injections of 30 milligrams per kilogram at 15 minutes after beginning the infusion of Escherichia coli and two hour infusions of 15 milligrams per kilogram at two hour intervals until death or for a 24 hour period . The mortality was unaltered by methylprednisolone . Six of seven baboons that were dying became progressively hypoglycemic, while hypoinsulinemia occurred in all baboons within six hours and was sustained until death . Systemic hypotension was observed . although pressures were variable . Potassium and lactate concentrations increased, while pH remained relatively constant in most baboons . Serum glutamic-pyruvic transaminase and arginase concentrations rose in most baboons dying with 18 hours . Results of morphologic studies revealed the presence of fibrin thrombi in the liver, kidney and adrenal tissue in most baboons . No significant differences in physiologic, metabolic, hematologic or morphologic parameters were observed between treated and untreated baboons.

Proc Natl Acad Sci U S A, 1978 Oct, 75(10), 4810 - 3
Iron, an essential element for biosynthesis of aromatic compounds; McCandliss RJ et al.; Homogeneous preparations of 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase {7-phospho-2-keto-3-deoxy-D-arabino-heptonate D-erythrose-4-phosphate lyase (pyruvate phosphorylating), EC 4.1.2.15} isolated as the enzyme-phosphoenolpyruvate complex from Escherichia coli are shown by atomic absorption analysis to contain approximately one mole of iron per mole of native enzyme . No cobalt was found, in contrast to suggestions of earlier workers . Pure enzyme preparations show a unique absorption maximum around 350 nm with an epsilon value of about 3500 M-1cm-1 . The 350-nm band as well as the enzyme activity is lost when the enzyme is denatured with guanidine-hydrochloride, or when phosphoenolpyruvate, the first substrate to bind to the enzyme, is totally removed from the enzyme by incubation with an excess of erythrose 4-phosphate, the second substrate to bind to the enzyme . The iron remains bound to the enzyme when phosphoenolpyruvate is removed from the enzyme-phosphoenolpyruvate complex.

Biochem J, 1978 Oct 1, 175(1), 1 - 13
Transcription of rat liver deoxyribonucleic acid in vitro at low ionic strength; Pays E; 1 . When RNA polymerase is in excess over DNA, the single-stranded breaks of DNA can be recognized as initiation sites for the ezyme . On the other hand stabel initiation complexes (resistant to inhibition by heparin) are the most abundant under these conditions . The formation of these complexes needs double-stranded DNA . It seems that RNA sequences rich in cytidine are preferentially synthesized; since rat liver DNA is A + T-rich, the transcription thus appears not to be random with respect to the base composition of DNA . 2 . When the template is in excess over the polymerase, the single-stranded gaps of DNA are preferentially transcribed by rat liver RNA polymerase B and native DNA regions by Escherichia coli RNA polymerase . 3 . With a large excess of DNA over the polymerase, the enzyme activity is markedly inhibited . This inhibition is proportional to the concentration of double-stranded DNA ends, but it also depends on the presence of a contaminant of DNA, removed when DNA is banded in a CsCl gradient . This contaminant could be polyphosphates . Low concentrations of spermine completely reverse this inhibition, by enhancing the rate of RNA chain elongation . 4 . Double-stranded RNA is synthesized in great abundance when RNA polymerase is in excess over native DNA . Besides a majority of symmetrical sequences, stable 'hairpins' can be found . Whereas the synthesis of symmetrical sequences is more prevalent in polymerase excess, it seems that the proportion of stable 'hairpins' in RNA is independent of the polymerase/DNA ratio.

J Bacteriol, 1978 Oct, 136(1), 85 - 95
Partial purification and properties of CTP:phosphatidic acid cytidylyltransferase from membranes of Escherichia coli; Langley KE et al.; The cytosine liponucleotides CDP-diglyceride and dCDP-diglyceride are key intermediates in phospholipid biosynthesis in Escherichia coli (C . R . H . Raetz and E . P . Kennedy, J . Biol . Chem . 248:1098--1105, 1973) . The enzyme responsible for their synthesis, CTP:phosphatidic acid cytidylytransferase, was solubilized from the cell envelope by a differential extraction procedure involving the detergent digitonin and was purified about 70-fold (relative to cell-free extracts) in the presence of detergent . In studies of the heat stability of the enzyme, activity decayed slowly at 63 degrees C . Initial velocity kinetic experiments suggested a sequential, rather than ping-pong, reaction mechanism; isotopic exchange reaction studies supported this conclusion and indicated that inorganic pyrophosphate is released before CDP-diglyceride in the reaction sequence . The enzyme utilized both CTP and dCTP as nucleotide substrate for the synthesis of CDP-diglyceride and dCDP-diglyceride, respectively . No distinction was observed between CTP and dCTP utilization in any of the purification, heat stability, and reaction mechanism studies . In addition, CTP and dCTP were competitive substrates for the partially purified enzyme . It therefore appears that a single enzyme catalyzes synthesis of both CDP-diglyceride and dCDP-diglyceride in E . coli . The enzyme also catalyzes a pyrophosphorolysis of CDP-diglyceride, i.e., the reverse of its physiologically important catalysis.

Boll Ist Sieroter Milan, 1978 Sep 30, 57(4), 403 - 12
The assessment of interaction between drugs by the Autobac 1 system; Visconti A; A study has been undertaken on the applicability of the Autobac 1 system to the checker board method to determine the interaction of combined drugs on bacterial populations . Preliminary results are reported which show that the Autobac makes easier, accurate, flexible and rapid such a method . In order to improve the significance and facilitate technical operations and data processing of this test additional equipment and device are suggested.

Biochimie, 1978 Sep 29, 60(6-7), 639 - 44
{Study of the lipopolysaccharide from a thermosensitive mutant CR-34 T 83 of Escherichia coli K 12}; Ouabonzi M et al.; The structure of the core of the lipopolysaccharide from T 83 mutant of Escherichia coli K 12 CR 34 was partially determined . Using dephosphorylation, enzymic hydrolysis, Smith degradation, methylations and analysis by gas chromatography/mass spectrometry an oligosaccharide sequence was determined with D-glucose, D-galactose and L-glycero-D-mannoheptose as sugar components . The structure which was demonstrated could be that of the characteristic core fragment of the K 12 type lipopolysaccharides from Escherichia coli.

Z Krebsforsch Klin Onkol Cancer Res Clin Oncol, 1978 Sep 28, 92(2), 177 - 214
The nucleotide-permeable Escherichia coli cell, a sensitive DNA repair indicator for carcinogens, mutagens, and antitumor agents binding covalently to DNA; Thielmann HW et al.; Ether-permeabilized (nucleotide-permeable) Escherichia coli cells respond to alkylating and arylalkylating carcinogens with DNA excision repair, as assessed by their stimulation of DNA repair synthesis . In the present work, we have investigated whether DNA repair synthesis in ether-treated E . coli cells can serve as a general indicator to monitor the DNA-binding of carcinogens, mutagens and antitumor agents . Therefore, a standard assay was developed and comparative analyses were performed on 11 ultimate carcinogens, 10 proximate carcinogens, 2 tumor promoters, 6 mutagens, and 12 antitumor agents . All ultimate carcinogens (alkylating, acylating, arylalkylating agents) and mutagens (e.g., hydrogeen peroxide, acridine derivatives) caused DNA excision repair in wild type cells as measured by {3H} dTMP incorporation and simultaneously inhibited replicative DNA synthesis to various extents . Control experiments with the mutant cells uvrA and uvrB were performed to determine whether the pyrimidine-dimer-specific UV-endonuclease was involved in the removal of DNA damage . This was found to be true for the ultimate carcinogens (Ac)2 ONFln, mitomycin C, and for very reactive alkylating carcinogens . None of the ultimate carcinogens induced repair polymerization in mutant cells lacking the 5'-3' exonucleolytic activity of DNA polymerase I . Proximate carcinogens, such as Me2NNO, 4-nitroquinoline-1-oxide and aflatoxins, did not induce excision repair in the standard assay, probably because of the inability of E . coli to perform the activation steps necessary for covalent DNA-binding . However, Me2NNO, when pretreated with Udenfriend's hydroxylating mixture, gave rise to a low level of repair polymerization in ether-treated cells . Intercalating mutagens, such as quinacrine and ethidum bromide, inhibited replicative DNA synthesis . However, they were not found to be repair-inducers . THE TUMOR PROMOters TPA and phorbol-12,13-didecanoate did not cause excision repair, even when applied at high concentrations, nor did they inhibit repair synthesis stimulated by MeNOUr or (Ac)2 ONFln . The antitumor agents may be classified into two groups on the basis of the influence they exert on DNA synthesis: members of the first group (involving BCNU and bleomycin) stimulate repair polymerization and, in addition, inhibit DNA replication . These compounds are known to bind covalently to DNA . The second group of drugs (including adriamycin and cis-Pt(II)diammine complexes) inhibits DNA replication without stimulating repair synthesis . The predominant DNA-interaction of these compounds is known to be a non-covalent (i.e., intercalative, electrostatic) binding . Our experiments show that the ether-permeabilized E . coli cell can be successfully used to test ultimate carcinogens, mutagens and antitumor agents for repair-inducing and replication-inhibiting activity . The standard test might be extended to pre- and proximate carcinogens, provided these can be suitably activated.

Z Krebsforsch Klin Onkol Cancer Res Clin Oncol, 1978 Sep 28, 92(2), 157 - 76
Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells . Analysis of DNA repair induced by carcinogenic K-region epoxides and 1,2,3,4-diepoxybutane; Thielmann HW et al.; Ether-permeabilized (nucleotide-permeable) Escherichia coli cells exhibited DNA excision repair when exposed to the following carcinogenic K-region epoxides: 7-methyl- and 7,12-dimethyl-benz{a}anthracene-5,6-oxide, chrysene-5,6-oxide and benzo{a}pyrene-4,5-oxide . This DNA excision repair was missing in uvr A and uvr B mutant cells . The K-region epoxide phenanthrene-9,10-oxide was ineffective in all E . coli strains tested . In contrast to the K-region epoxides which where found active only in wild type cells, 1,2,3,4-diepoxybutane and the 6,7-epoxides of the tumor promoter TPA (12-O-tetradecanoyl-phorbol-13-acetate) elicited DNA repair in uvrA, uvrB mutant cells as well . Enzymic activities catalyzing particular repair steps were identified by determining a) repair polymerization and b) size reduction of denatured DNA . A) An easily quantifiable effect in E . coli wild type cells was epoxide-induced repair polymerization . None of the K-region epoxides tested stimulated DNA repair synthesis in uvrA, uvrB mutant cells, indicating that the uvrA-, uvrB-controlled UV-endonuclease initiated excision repair by cleaving epoxide-damaged DNA . 1,2,3,4-Diepoxybutane and the TPA-6,7-oxides induced DNA repair polymerization in uvr-deficient cells, although to a lesser extent than in wild type cells, suggesting the involvement of uvr-independent incision steps . None of the epoxides induced repair polymerization in a mutant (polA107) lacking the 5'--3'exonucleolytic activity of DNA polymerase I (exonuclease VI) . The absence of any repair polymerization in the polA107 mutant indicates that the exonuclease VI plays a central role in removing epoxide-damaged nucleotides . As evidenced by greatly reduced levels of repair polymerization measured in polA1 cells, DNA polymerase I was the main polymerizing enzyme . b) As a consequence of treatment with 7-methyl-benz{a}anthracene-5,6-oxide, DNA from wild type cells, contrary to uvrA mutant cells, showed size reduction after denaturation and sedimentation in alkaline sucrose gradients . This is explained by repair-specific endonucleolytic cleavage of damaged DNA . The incision required the presence of ATP indicating that functional UV-endonuclease needs ATP as a cofactor.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 441 - 51
Polynucleotides . XLIV . Synthesis and properties of poly (2-azaadenylic acid) and poly(2-azainosinic acid); Fukui T et al.; Chemically synthesized 2-azaadenosine 5'-diphosphate (n2ADP) and 2-azainosine 5'-diphosphate (n2IDP) were polymerized to yield poly(2-azaadenylic acid), poly(n2A), and poly(2-azainosinic acid), poly(n2I), using Escherichia coli polynucleotide phosphorylase . In neutral solution, poly(n2A) and poly(n2I) had hypochromicities of 32 and 5.5%, respectively . Poly(n2A) formed an ordered structure, which had a melting temperature (Rm) of 20 degrees C at 0.15 M salt concentration . Upon mixing with poly(U), poly(n2A) formed a 1 : 2 complex with Tm of 41 degrees C at 0.15 M salt concentration . Poly(n2A) and poly(n2I) formed three-stranded complexes with poly(I), and poly(A), respectively . Poly(n2A) . 2poly(I), poly(A) . 2poly(n2I), and poly(n2A) . 2poly(n2I) complexes had Tm values of 23, 48, and 31 degrees C at 0.15 M salt concentration, respectively . Poly(n2I) formed a double-stranded complex with poly(C), but its Tm was very low.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 411 - 8
In vitro methylation of tobacco mosaic virus RNA with ribothymidine-forming tRNA methyltransferase . Characterization and specificity of the reaction; Lesiewicz J et al.; A novel method has been developed for the detection and study of tRNA-like moieties in viral RNAs . Tobacco mosaic virus RNA is an acceptable substrate for crude Escherichia coli ribothymidine-forming tRNA methyltransferase . Under optimum reaction conditions at least 85% of the methylation product is ribothymidine (rT) . The reaction is essentially quantitative, 1 mol of rT being formed per mol of tobacco mosaic virus RNA . The optimum reaction conditions include the presence of 6.6 micrometers S-adenosyl-L-{Me-3H}methionine, 25 micrometers spermine, 25 mM ammonium acetate, and 50 mM HEPES, pH 8.0 . Sequence analysis of (Me-3H)-labeled tobacco mosaic virus RNA shows that all of the methylation occurs at a single site and strongly suggests that this site is the 32nd residue from the 3'-end of tobacco mosaic virus RNA . This site closely resembles the normal position of rT in transfer RNA.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 331 - 41
Two novel growth cycle-reflecting proteins associated with Escherichia coli ribosomes; Minks MA et al.; The isolation and characterization of two low molecular weight, growth cycle-reflecting proteins which are associated with Escherichia coli ribosomes is described . These proteins which show greatly enhanced stoichiometry in ribosomes derived from post-exponential cells, exhibit molecular weights of 16 600, and 11 700 on sodium dodecyl sulfate (SDS) gel electrophoresis . Both proteins are highly acidic, the larger being the most acidic protein associated with the ribosome . Their amino acid compositions are unique and distinguish them from all other ribosomal proteins . Neither of the proteins showed crossreaction with either anti-L7 or anti-S6 sera although their electrophoretic behavior resembles that of L7 and S6 . During the purification we have also isolated small amounts of three low molecular weight proteins showing some immunological homology with L7/L12 . The isolated proteins were found to be without effect on the in vitro translation of f2-RNA, indicating that these adaptive modifications of the ribosome do not seriously affect its intrinsic activity.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 317 - 30
Influence of polyamines on the activity of DNA polymerase I from Escherichia coli; Osland A et al.; The influence of polyamines on the various activities of DNA polymerase I from Escherichia coli (EC 2.7.7.7) has been investigated . For all high molecular weight DNAs spermine and spermidine caused up to 80% inhibition when present in high concentrations, i.e . above 1 mM for spermine and 2 mM for spermidine . In the presence of low concentrations of polyamines a small activation was seen for some DNAs . The diamines cadaverine and putrescine had little influence on the rate of synthesis with natural occurring DNAs . In the case of d(A--T)n the activation/inhibition was found to be markedly dependent on the molecular weight of the samples used . With a low molecular weight DNA, 5.6 S, addition of spermidine resulted in up to 3-fold stimulation of activity . The activation was dependent on the concentration of MgCl2 and ionic strength; increasing concentration of these gave a decrease in the degree of activation . Polyamines also had a dramatic effect on the rate of synthesis using the homopolymers (dA)n . (dT)10 and (rA)n . (dT)10 . (20:1) as primers . Putrescine, in particular, increased the activity up to 10-fold with (rA)n . (dT)10 and somewhat less for (dA)n . (dT)10 . The apparent Km for the primer (rA)n . (dT)10 decreased approx . 35-fold in the presence of 6.6 mM putrescine . There was no influence on the apparent Km for dTTP . The influence of polyamines on both the 5' leads to 3' and 3' leads to 5' nuclease activity was also investigated . Inhibition of nuclease activity was observed in the presence of polyamines, particularly with spermine . Thus with d(A--T)n and T7 DNA as substrates addition of 0.7 mM spermine resulted in almost complete inhibition of the activity . The dramatic inhibition observed with high concentrations of spermine (spermidine) both in the case of polymerizing and nuclease activity is thought to be due to polyamine-induced aggregation of DNA molecules.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 285 - 90
Effect of DNA denaturants on the lac repressor-operator interaction; Pfahl M; The nitrocellulose filter assay was used to study the effect of the DNA denaturants glycerol and dimethylsulfoxide (Me2SO) on the lac repressor-operator interaction . Both glycerol and Me2SO decrease the rate of dissociation (kb) of the repressor-operator complex but do not significantly alter the rate of association of repressor and operator . In the presence of 10% Me2SO an almost 10-fold increase of affinity of repressor for operator is observed . A small increase in affinity of repressor for Escherichia coli DNA, chicken blood DNA, and poly(dA-dT) is also found . The results lead to the conclusion that lac repressor when interacting with the operator causes local destabilization of the DNA.

Biochim Biophys Acta, 1978 Sep 27, 520(2), 342 - 57
Specific association of two homologous DNA-binding proteins to the native 30-S ribosomal subunits of Escherichia coli; Suryanarayana T et al.; The native 30-S ribosomal subunits from Escherichia coli are shown to be associated with two proteins which are different from the known ribosome-associated and ribosomal proteins . Neither protein is foune on native 50-S subunits or on intact ribosomes in the cell extract . The purified proteins re-bind in vitro to free 30-S subunits, but do not bind to either free 50-S subunits or intact ribosomes . The proteins, denoted NS1 and NS2, have been purified and characterized . Both proteins showed the same molecular weight of 9500 by sodium dodecyl sulfate gel electrophoresis but 34 000 by gel filtration . Upon treatment with cross-linking reagents the purified proteins gave higher molecular weight species up to the tetrameric ones showing that they exist in solution as tetramers . The amino acid compositions, tryptic fingerprint patterns and N-terminal sequences of the two proteins have been determined . These data show that NS1 and NS2 possess distinct primary structures but with extensive sequence homology . Antibodies raised against the purified proteins cross-reacted in double immuno-diffusion tests confirming further the homology . Because of the similarity in properties a sample of the DNA-binding protein HD (Berthold, V . and Geider, K . (1976) Eur . J . Biochem . 71, 443--449) was compared to NS1 and NS2 . In terms of several criteria, the protein HD is found to be a mixture of two proteins, namely NS1 and NS2 . The present report is the first instance of an association of DNA-binding proteins to the ribosome.

J Biol Chem, 1978 Sep 25, 253(18), 6354 - 63
Biosynthesis in Escherichia coli of sn-glycerol 3-phosphate, a precursor of phospholipid . Kinetic characterization of wild type and feedback-resistant forms of the biosynthetic sn-glycerol-3-phosphate dehydrogenase; Edgar JR et al.; Homogeneous wild type and feedback-resistant forms of the biosynthetic sn-glycerol 3-phosphate (glycerol-P) dehydrogenase of Escherichia coli (EC1.1.1.8) were subjected to two-substrate kinetic analysis . The kinetics of the NADPH-dependent reduction of dihydroxyacetone phosphate (dihydroxyacetone-P) and of the NADP-dependent oxidation of glycerol-P indicate that these reactions proceed by a sequential mechanism . Glycerol-P was a competitive inhibitor with respect to dihydroxyacetone-P for both enzymes . The wild type and feedback-resistant glycerol-P dehydrogenases had Ki values for glycerol-P of 4.4 micrometer and 43 micrometer, respectively . Therefore, the sensitivity of the wild type activity and reduced sensitivity of the feedback-resistant activity, both noted previously in crude extracts, were inherent properties of the enzymes . The patterns of product inhibition for both enzymes were identical, and the difference in the inhibition constants for glycerol-P occurred without significant alteration of any other kinetic constant determined . Kinetic mechanisms consistent with the patterns of product inhibition violated Haldane relationships and other kinetic relationships . These discrepancies suggest that glycerol-P inhibition occurs at a site distinct from the active site . The pH dependencies of the Km for dihydroxyacetone-P and the Ki for glycerol-P were markedly different suggesting the existence of an allosteric site . The addition of glycerol-P in the presence of NADPH stabilized both enzymes against thermal inactivation . Half-maximal stabilization was provided by 5 micrometer and 50 micrometer glycerol-P for the wild type and feedback-resistant enzymes, respectively . These kinetic data, considered in conjunction with previous physiologic and genetic data, indicate that the synthesis of glycerol-P is regulated in vivo by glycerol-P inhibition of the glycerol-P dehydrogenase . The data suggest that glycerol-P inhibition occurs at an allosteric, regulatory site.

Biochim Biophys Acta, 1978 Sep 22, 512(2), 365 - 76
Insertion of newly synthesized proteins into the outer membrane of Escherichia coli; de Leij L et al.; The insertion of newly synthesized proteins into the outer membrane of Escherichia coli has been examined . The results show that there is no precurser pool of outer membrane proteins in the cytoplasmic membrane because first, the incorporation of a {35S}methionine pulse into outer membrane proteins completely parallels its incorporation into cytoplasmic membrane proteins, and second, under optimal isolation conditions, no outer membrane proteins are found in the cytoplasmic membrane, even when the membranes are analysed after being labeled for only 15 s . The {35S}methionine present in the outer membrane after a pulse of 15 s was found in protein fragments of varying sizes rather than in specific outer membrane proteins . This label could however be chased into specific proteins within 30--120 s, depending on the size of the protein, indicating that although unfinished protein fragments were present in the outer membrane, they were completed by subsequent chain elongation . Thus, outer membrane proteins are inserted into the outer membrane while still attached to ribosomes . Since ribosomes which are linked to the cell envelope by nascent polypeptide chains are stationary, the mRNA which is being translated by these ribosomes moves along the inner cell surface.

Mol Gen Genet, 1978 Sep 20, 165(1), 65 - 71
Structure of recombinant plasmids containing synthetic human foetal globin gene sequences; Humphries P et al.; In vitro synthesized duplex DNA complementary to human foetal globin messenger RNA was integrated into bacterial plasmids and amplified by transformation of Escherichia coli . Recombinants carrying globin DNA were identified by hybridization of foetal globin messenger RNA to bacterial DNA in situ and by liquid hybridization of purified plasmids to specific globin complementary DNA probes . Heteroduplex mapping revealed either a simple insertion loop at the position of the EcoRI site of the parental plasmid DNA . We provide evidence to suggest that these deletions are the result of a site-specific nicking activity of the EcoRI preparations used in the formation of recombinant plasmids.

Mol Gen Genet, 1978 Sep 20, 165(1), 95 - 102
Synthesis of tryptophanase in Escherichia coli: isolation and characterization of a structural-gene mutant and two regulatory mutants; Taylor HV et al.; A mutant of E . coli has been isolated that is temperature-sensitive in respect of tryptophanase . When incubated at 60 degrees C, cell-free extracts of the mutant suffer inactivation of enzyme activity much more rapidly than similar extracts of the wild type . After lysogeny with a specialized transducing phage carrying the wild-type tryptophanase gene, the mutant is able to synthesize tryptophanase that is wild-type in its response to treatment at 60 degrees C . It is concluded that the mutation lies in the structural gene for the enzyme . Two further mutants have been isolated that synthesize tryptophanase constitutively . One mutation renders synthesis of the enzyme indifferent to the presence of inducer; the other mutation allows synthesis of the enzyme in the absence of inducer at about 35% of the fully induced wild-type rate . Neither mutation alleviates catabolite repression . Genetic mapping shows that the constitutive mutations lie very close to the structural-gene mutation, on the side of the structural gene distant from bglR.

Mol Gen Genet, 1978 Sep 20, 165(1), 87 - 93
Uvm mutants of Escherichia coli K12 deficient in UV mutagenesis . I . Isolation of uvm mutants and their phenotypical characterization in DNA repair and mutagenesis; Steinborn G; Selection for defective reversion induction, after UV treatment of E . coli K 12, yielded uvm mutants . These mutants exhibited highly reduced or no UV mutability for all loci tested although they were moderately and normally mutable by X-rays and EMS, respectively . Uvm mutations confer only a slight sensitivity to killing by UV and X-rays and no clear sensitivity to the lethal effect of HN2, EMS or MMS . Growth and viability of untreated uvm cells were normal . The properties of uvm mutants are discussed in relation to those of other relevant mutant types and to some actual problems of induced mutagenesis.

Mol Gen Genet, 1978 Sep 20, 165(1), 73 - 8
Mutational alterations in 50 proteins of the Escherichia coli ribosome; Dabbs ER; A strain of Escherichia coli, VT, which spontaneously gives rise to mutations in many ribosomal proteins, has been used in conjunction with chemical mutagenesis and varying the subsequent incubation temperature to select mutants which have alterations in every ribosomal protein amenable to analysis of 70 S proteins on two-dimensional polyacrylamide gels under standard conditions . Alterations have been detected in 50 ribosomal proteins, namely in 20 from the small and in 30 from the large subunit . This is the most complete set of mutants with altered ribosomal proteins described so far . The difficulty until recently in obtaining mutations in most ribosomal proteins arises not because they are lethal, as has often been supposed, but because of the lack of a suitable selection heretofore.

Mol Gen Genet, 1978 Sep 20, 165(1), 21 - 30
Correlation between the serine sensitivity and the derepressibility of the ilv genes in Escherichia coli relA- mutants; Uzan M et al.; Upon addition of excess one carbon metabolites (including serine)bacteria stop growing because of isoleucine starvation . After such treatment stringent bacteria rapidly resume normal growth whereas relaxed mutants remain unable for some time to grow . We show here that this is due to a lack of derepressibility of ilv genes after the starvation period . Results are also presented which show that RNA polymerase structural mutants may be selected among the clones resistant to a mixture of serine, methionine and glycine, in relA- strains . Finally circumstancial evidence suggests that the one carbon metabolism may be involved in a process controlling isoleucine metabolism.

Mol Gen Genet, 1978 Sep 20, 165(1), 15 - 20
Mutations affecting the structural genes and the genes coding for modifying enzymes for ribosomal proteins in Escherichia coli; Isono S et al.; Temperature-sensitive mutants of an Escherichia coli K-12 strain PA3092 have been isolated following mutagenesis with nitrosoguanidine, and their ribosomal proteins analyzed by two-dimensional gel electrophoresis . This method was found to be very efficient in obtaining mutants with various structural alterations in ribosomal proteins . Thus a total of some 160 mutants with alterations in 41 different ribosomal proteins have so far been isolated . By characterizing these mutants, we could isolate not only those mutants with alterations in the structural genes for various ribosomal proteins, but also those with impairments in the modification of proteins S5, S18 and L12 . Furthermore, a mutant has been obtained which apparently lacks the protein S20 (L26) with a concomitant reduction to a great extent of the polypeptide synthetic activity of the small subunit . The usefulness of these mutants in establishing the genetic architecture of the genes coding for the ribosomal proteins and their modifiers is discussed.

Mol Gen Genet, 1978 Sep 20, 165(1), 1 - 6
RNA polymerase mutant with altered sigma factor in Escherichia coli; Nakamura Y; A structural gene for sigma factor (rpoD) of DNA-dependent RNA polymerase (RNA nucleotidyltransferase; nucleoside-triphosphate: RNA nucleotidyltransferase, E.C . 2.7.7.6) was mapped precisely by a set of F' factors including those already published (Proc . Natl . Acad . Sci . USA . 74, 1831-1835 (1977)) . Based on the result that rpoD is located at the dnaG-uxaAC region, a number of mutants containing a temperature-sensitive mutation at or near the uxaA gene were isolated by localized mutagenesis . One of these mutants was found to produce RNA polymerase altered in both thermostability and optimum salt concentration as a result of structural alteration of sigma factor . This mutation, U303, maps at 66 min on the genetic map of E . coli, near the dnaG locus, and affects normal growth of cells.

Mol Gen Genet, 1978 Sep 20, 165(1), 47 - 56
The cyclic 3',5'-adenosine monophosphate receptor protein and regulation of cyclic 3',5'-adenosine monophosphate synthesis in Escherichia coli; Botsford JL et al.; Rates of synthesis of cyclic 3',5'-adenosine monophosphate (cAMP) were measured in cultures of Escherichia coli aerating without a carbon source . This technique provides a representative measure of adenylate cyclase activity in the absence of inhibition caused by transport of the carbon source . Adenylate cyclase activity was found to vary more than 20-fold depending on the carbon source that had been available during growth . Synthesis of cAMP in cells aerating in the absence of the carbon source was highest when cells had been grown with glucose or fructose which inhibit adenylate cyclase activity severely . Synthesis of cAMP was much lower when cells had been grown with glycerol or succinate which cause only minimal inhibition of the activity . The variation in cAMP synthesis due to different carbon sources requires a functional cAMP receptor protein (CRP) . Crp- mutants synthesize cAMP at comparable rates regardless of the carbon source that afforded growth . A novel mutant of E . coli having a CRP no longer dependent on cAMP has been isolated and characterized . Adenylate cyclase activity in this mutant no longer responds normally to variations in the carbon source.

Biochemistry, 1978 Sep 19, 17(19), 4078 - 85
Fluorescence and chemical studies on the interaction of Escherichia coli DNA-binding protein with single-stranded DNA; Bandyopadhyay PK et al.; Nanosecond and steady-state fluorescence spectoscopy were used to probe the environment of the tryptophan residues of Escherichia coli DNA-binding protein . A spectral shift and a change in quantum yield of the protein upon binding to DNA or oligonucleotides indicate that the tryptophan residues are near or at the DNA binding site . The observation of two excited-state lifetimes of the protein indicates that there is heterogeneity in the microenvironments of these tryptophan residues . The "short-lifetime" tryptophan residues are more sensitive to the interaction with DNA than the "long-lifetime" residues . The results of solute-perturbation studies with iodide or acrylamide indicate that there are tryptophan residues near the surface of the protein which are heterogeneous in their accessibility to these quenchers and that they become less accessible after DNA binding . Also, lysine residues of the protein have been shown to be essential to DNA binding by chemical-modification studies . Tyrosine, arginine, and cysteine residues appear not to be involved in this binding process . From studies of the decay of fluorescence anisotropy of the binding protein in the presence and absence of DNA, it has been concluded that (a) the tetrameric binding protein does not dissociate into subuniits upon binding to the oligonucleotide d(pT)16 and (b) the binding protein-fd DNA complex possesses "local flexibility" and, therefore, cannot be described as a continuous, rigid rod.

Biochem J, 1978 Sep 15, 174(3), 717 - 25
The location of purine phosphoribosyltransferase activities in Escherichia coli; Page MG et al.; During the preparation of spheroplasts, adenine phosphoribosyltransferase (EC 2.4.2.7) and hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) were released in parallel with cytidine deaminase (EC 3.5.4.5) and uridine phosphorylase (EC 2.4.2.3), which, on other evidence, are considered to be located intracellularly . The two phosphoribosyltransferases and uridine phosphorylase were not significantly associated with purified membrane fractions as was purine nucleoside phosphorylase (EC 2.4.2.1) . The effects of the poorly permeable enzyme-inactivating reagents, 4-diazoniumbenzenesulphonate, 7-diazonium-1,3-naphthalene-disulphonate and 2,4,6-trinitrobenzenesulphonate, on Escherichia coli indicate that all the above-mentioned enzymes and also the xanthine-guanine phosphoribosyltransferase {Miller, Ramsey, Krenitsky & Elion (1972) Biochemistry 11, 4723--4731} are located intracellularly.

Experientia, 1978 Sep 15, 34(9), 1154 - 5
Dithiols simulate endotoxin in the Limulus reaction; Platica M et al.; Dithiothreitol, dithioerythritol and bacterial lipopolysaccharides increase optical absorbance and clot Limulus lysate . Purification of dithiothreitol from possible endotoxin contamination by vacuum sublimation or chromatography does not abolish the reaction with lysate . The dithiols reported active here represent the smallest molecules capable of simulating endotoxin in the Limulus test.

Eur J Biochem, 1978 Sep 15, 90(1), 83 - 8
Polynucleotide-protein interactions in the translation system . Detection of contacts between some ribosomal split proteins and 16-S RNA in 30-S subunits of Escherichia coli ribosomes; Turchinsky MF et al.; Direct contacts between 16-S RNA and split proteins S2, S3, S5, S14 and S21 inside the 30-S subunit of Escherichia coli ribosomes were evidenced by the formation of ultraviolet-induced (lambda = 254 nm) RNA-protein cross-links . 30-S subunits were reassembled from core particles and a mixture of split proteins containing in each case a single 125I-labelled protein . All the proteins tested are cross-linked as a result of a single-hit process; proteins S3 and S21 were cross-linked at the highest rate.

Eur J Biochem, 1978 Sep 15, 90(1), 107 - 12
Dioxygen and temperature dependence of ubiquinone formation in Escherichia coli: studies of cells charged with 2-octaprenyl phenol; Knoell HE et al.; The multiple aromatic auxotroph Escherichia coli K-12 strain AB 2847 (aroB-) was conditioned for efficient ubiquinone-8 formation . Resting cells readily convert 4-hydroxy{U-14C}benzoate into ubiquinone-8 (60 nmol per g wet weight) . Under argon this processing stops at the stage of 2-octaprenyl phenol . Only upon admission of air is the pool of 2-octaprenyl phenol converted to ubiquinone-8 . This reaction occurs in the cytoplasmic membrane and is significantly inhibited by cytochrome P-450 inhibitors . The rate for 2-octaprenyl phenol conversion is strongly dependent on temperature . The Arrhenius plot shows inflection points at 32 degrees C and 16 degrees C . Enzymes for ubiquinone-8 synthesis are absent from anaerobically grown E . coli . Processing of 4-hydroxy{U-14C}benzoate by these cells starts only when protein synthesis is permitted under aerobic conditions.

Eur J Biochem, 1978 Sep 15, 90(1), 161 - 9
Isolation and characterization of RNA polymerase B from the larval fat body of the tobacco hornworm, Manduca sexta; Sridhara S et al.; DNA-dependent RNA polymerase B has been extensively purified from the larval fat body of the tobacco hornworm (Manduca sexta) by employing chromatography on ion-exchange columns of DEAE-Sephadex, DEAE-cellulose and phosphocellulose and centrifugation on glycerol gradients . The isolated enzyme after electrophoresis on acrylamide gels shows one main band and one minor band, both having enzyme activity sensitive to alpha-amanitin . The catalytic and physicochemical properties of the enzyme are similar to those of other eucaryotic B-type RNA polymerases . The enzyme has an apparent molecular weight of 530000, is inhibited 50% by alpha-amanitin at 0.04 microgram/ml and shows maximum activity on denatured DNA at 5 mM Mn2+ and 100 mM ammonium sulfate . An antibody was obtained that cross-reacts with the pure enzyme and forms a precipitin line . This antibody does not cross react with either Escherichia coli RNA polymerase or with wheat germ RNA polymerase but does react with one of the B polymerases isolated from wing tissue of the silkmoth, Antheraea pernyi.

Biochim Biophys Acta, 1978 Sep 11, 526(1), 267 - 75
Enhanced allosteric regulation of threonine deaminase and acetohydroxy acid synthase from Escherichia coli in a permeabilized-cell assay system; Blatt JM et al.; A permeabilized-cell technique for rapid assay of enzyme activity has revealed enhanced allosteric regulation of both threonine deaminase (L-threonine hydrolyase (deaminating), EC 4.2.1.16) and acethohydroxy acid synthease (acetolactate pyruvate-lyase (carboxylating), EC 4.1.3.18) in Escherichia col K-12 . In the permeabilized cell assay threonine deaminase exhibited a higher Hill coefficient for inhibition by L-isoleucine, and acetohydroxy acid synthase exhibited a hypersensensitivity to allosteric inhibition by L-valine when compared to studies on crude extracts . We propose that these effects reflect the in situ microenvironments of both enzymes . Preliminary evidence further indicates that acetohydroxy acid synthase may loosely associate with the cell membrane.

Biochim Biophys Acta, 1978 Sep 11, 526(1), 135 - 46
Zinc stoichiometry in Escherichia coli alkaline phosphatase . Studies by 31P NMR and ion-exchange chromatography; Bock JL et al.; 31P nuclear magnetic resonance spectra and enzymatic activities are compared for alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) species with different zinc contents . The enzyme containing two Zn2+ per protein dimer exists in two forms; one, prepared by dialysis of native enzyme, has full enzymatic activity and a 31P magnetic resonance spectrum similar to but distinguishable from that of the native enzyme containing four or more Zn2+ . The other form, prepared by restoring two Zn2+ to apoenzyme, has low enzymatic activity and a 31P magnetic resonance spectrum that indicates stoichiometric binding of phosphate, but otherwise altered properties . Reconstituted enzyme with four Zn2+ is similar to but distinguishable from native enzyme with four Zn2+ . Chromatography on DEAE-cellulose can separate apoenzyme and enzyme containing two Zn2+ and suggests that the binding of a pair of Zn2+ is cooperative.

J Biol Chem, 1978 Sep 10, 253(17), 6266 - 9
An active alpha'2beta2 derivative of tryptophean synthase formed by limited proteolysis; Miles EW et al.; A new approach to studying the arrangement of subunits in the multienzyme complex tryptophan synthase is reported . Comparative studies of limited tryptic proteolysis of the alpha2beta2 complex and of the separate beta2 and alpha subunits show that subunit association inhibits two types of proteolysis which occur with the separate subunits: (i) cleavage of the beta2 subunit to two fragments with consequent loss of activity and (ii) complete degradation of the alpha subunit with loss of activity . Trypsin treatment of the alpha2beta complex does, however, result in at least one cleavage of the alpha subunit and yields an active alpha'2beta2 complex . The alpha'2beta2 complex can be resolved into an active beta2 subunit and an active alpha derivative termed alpha' . These two species can reassociate into the active alpha'2beta2 complex . alpha' derivative can be separated into a large fragment of Mr approximately 20,000 to 23,000 and a small peptide by polyacrylamide gel electrophoresis under denaturing conditions.

J Biol Chem, 1978 Sep 10, 253(17), 6211 - 7
Phosphate binding to Escherichia coli alkaline phosphatase . Evidence for site homogeneity; Bloch W et al.; The reversible, noncovalent binding of inorganic phosphate to Escherichia coli alkaline phosphatase at pH 8 has been examined by equilibrium dialysis at two temperatures and two ionic strengths . Binding occurs with a stoichiometry of two phosphate ions per dimeric enzyme molecule and a single dissociation constant that is not very sensitive to temperature or ionic strength . These results contradict published evidence for anti-cooperative binding of inorganic phosphate to alkaline phosphatase . Reasons are presented for believing that the apparent anti-cooperativity reported by other workers is artifactual.

J Biol Chem, 1978 Sep 10, 253(17), 6255 - 9
Membrane cooperative enzymes . High molecular specificity for blocking action of thyroxine on triiodothyronine effect in rat erythrocyte and Escherichia coli systems; de Mendoza D et al.; The molecular specificity for the blocking action of thyroxine on the triiodothyronine effect in the cooperativity of membrane-bound rat erythrocyte acetylcholinesterase and Escherichia coli Ca2+-ATPase was analyzed . Changes in the values of n (Hill coefficient) were obtained at strict physiological levels of these hormones . The structural requirements of the thyroid hormones to modify the membrane-bound systems were studied using various analogues of these hormones . In the erythrocyte system, a very high molecular specificity for triiodothyronine and thyroxine actions was found . The L-alanine side is essential to carry out both the allosteric desensitization and the blocking effects . The blocking ability of thyroxine is characterized by the presence of iodine in the 5' position . The bacterial system presented only specificity for the triiodothyronine allosteric desensitization . A system of membrane-bound enzymes for the study of the actions of thyroid hormones, is presented here.

J Biol Chem, 1978 Sep 10, 253(17), 5877 - 9
Enzymatic excision of free hypoxanthine from polydeoxynucleotides and DNA containing deoxyinosine monophosphate residues; Karran P et al.; A DNA glycosylase that releases free hypoxanthine by selective cleavage of dIMP residues in polydeoxynucleotides and DNA containing this nonconventional nucleotide is present in Escherichia coli cell extracts . The partly purified enzyme, termed hypoxanthine-DNA glycosylase, does not require divalent cations or phosphate for activity, and it acts more efficiently on double-stranded than on single-stranded substrates . The enzyme has properties different from either uracil-DNA glycosylase or 3-methyladenine-DNA glycosylase and is present at normal levels in E . coli mutants deficient in either of the latter two DNA glycosylases.

Mol Gen Genet, 1978 Sep 8, 164(3), 259 - 64
A DNA segment within the colicin E1 structural gene on ColE1 affecting immunity to colicin; Shafferman A et al.; Insertion of DNA at the EcoRI site of ColE1 results in increase of immunity to colicin killing in E . coli harboring such recombinant ColE1 plasmid as compared to E . coli (ColE1) . This effect is neither due to cis or trans interactions originating from the inserted foreign DNA fragment, nor to changes in plasmid copy number . This defect in the immunity mechanism is not trans complemented for by wild type ColE1 . Increase in immunity can also be obtained by deleting a DNA segment from the ColE1 genome . This segment is approximately 120 bp left to the EcoRI site within the colicin structural gene . It is concluded that the structure of DNA per se, around the EcoRI site, within colcin structural gene, is the structure which affects immunity expression.

Biochim Biophys Acta, 1978 Sep 6, 542(3), 442 - 55
Insulin action on Escherichia coli . Regulation of the adenylate cyclase and phosphotransferase enzymes; Abou-Sabe' M et al.; Insulin on Escherichia coli was studied using wild type E . coli B/r and K12 strains and a number of phosphoenolpyruvate phosphotransferase mutants . In vivo, the effects of insulin on the differential rate of tryptophanase synthesis, the rate of alpha-methylglucoside uptake and the rate of growth on glucose were determined in E . coli B/r . In vitro, the effect of insulin on the adenylate cyclase and the phosphotransferase activities was determined using toluenized cell preparations of E . coli B/r, E . coli K12 and phosphotransferase mutant strains . The specificity of insulin action on E . coli was determined using glucagon, vasopressin and somatropin as well as insulin antisera . Results show the specific action of insulin on E . coli, inhibiting tryptophanase induction and adenylate cyclase activity, while stimulating growth on glucose and uptake and phosphorylation of alpha-methylglucoside.

Biochemistry, 1978 Sep 5, 17(18), 3889 - 92
Ionic strength perturbation kinetics of gene 32 protein dissociation from its complex with single-stranded DNA; Peterman BF et al.; Equilibrium and kinetic studies of the interaction of gene 32 protein of T4 phage with single-stranded fd DNA were performed monitoring the changes in protein fluorescence . From the fluorescence titrations, it was estimated that a monomer of gene 32 protein covered six nucleotide bases on the DNA and the lower limit for the apparent association constant was 1.9 x 10(8) M-1 with a cooperative parameter of 10(3) in 0.1 M 2-amino-2-hydroxymethyl-1,3-propanediol hydrochloride (pH 7) at 25 degrees C . When an ionic strength jump was applied to the gene 32 protein-fd DNA complex using a stopped-flow apparatus, the complex underwent a dissociation into its individual components accompanied by an increase in protein fluorescence . The kinetics of the dissociation are not consistent with a single first-order process . The data, however, can be analyzed in terms of a model in which gene 32 protein molecules release cooperatively starting from either one or both ends of a cluster of proteins bound to fd DNA . This type of dissociation of gene 32 protein from single-stranded DNA is very efficient and has interesting implications: it could provide a way to facilitate a rapid "zippering" of the two complementary DNA strands during DNA replication and genetic recombination.

Biochemistry, 1978 Sep 5, 17(18), 3833 - 40
Stable isotope studies on the biosynthesis of the thiazole moiety of thiamin in Escherichia coli; White RH; Deuterated and 13C-labeled sugars were fed to Escherichia coli growing on defined medium . The position and extent of incorporation of the label into the 4-methyl-5-beta-hydroxyethylthiazole portion of thiamin and other cellular components were measured by gas chromatography-mass spectrometry . Based on the findings, it is concluded that the contiguous five-carbon unit of the 4-methyl-5-beta-hydroxyethylthiazole is biosynthetically derived from pyruvate and a triose phosphate.

Biochemistry, 1978 Sep 5, 17(18), 3883 - 8
Addition of poly(adenylic acid) to RNA using polynucleotide phosphorylase: an improved method for electron microscopic visualization of RNA-DNA hybrids; Engel JD et al.; We have observed that the enzyme polynucleotide phosphorylas from M . luteus or from E . coli will polymerize adenosine (A) from adenosine diphosphate onto 3' ends of RNA molecules . For gene mapping, the poly(A)-tailed RNA is hybridized to its complementary sequence on a longer DNA strand . The position of the poly(A)tail, and thus the position of the 3' end of the RNA on the DNA strand, can then be observed by electron microscopy . Our preferred mapping technique involves the synthesis of a poly(A)-specific label by polymerization of a poly(dBrU) tail onto one or both ends of a linear duplex DNA of defined length (a restriction fragment) and hybridization of this label to the poly(A) tail . In test experiments with a plasmid containing a Drosophila DNA sequence coding for 5S rRNA genes, overall labeling efficiencies of 70--80% were achieved.

Biochimie, 1978 Sep 4, 60(5), 467 - 71
An immunological determination of specific activities of enzymes: its use in quantification of cross reactivity between enzymes of different origins; Guiso N et al.; An immunological method is presented which enables the determination of the specific activity of a pure enzyme without its extensive purification . The method consists essentially in the specific fixation of immunologically related enzymes to an immunoadsorbent containing specific antibodies raised against the wild-type form of the enzyme . We applied this method to determine the specific activity of plasmid-coded beta-galactosidases and to quantify the extent of cross-reaction between these enzymes and Escherichia coli beta-galactosidase.

Nucleic Acids Res, 1978 Sep, 5(9), 3315 - 24
Polynucleotides . LVI . Synthesis and properties of poly(2-deoxy-2'-fluoroinosinic acid); Ikehara M et al.; Poly (2'-deoxy-2'-fluoroinosinic acid) { poly(If)} was synthesized by polymerization of 2'-deoxy-2'-fluoroinosine 5'-diphosphate catalyzed by Escherichia coli polynucleotide phosphorylase . Although the UV absorption properties of poly(If) closely resembled those of poly(I), thermal melting curves at Na+ concentrations of 0.15M and 0.75M suggested two ordered structures for poly(If) neutral form . CD psectra taken at 0.15M Na+ concentration showed rather larger amplitudes in both a peak at 273 nm and a trough at 246 nm, suggesting rather strong vertical stacking of bases . When complexed with poly(C), poly(If) forms a double-stranded complex, poly(If).poly(C) which has Tm's higher by 10-20 degrees than those of poly(If).poly(C) measured under the same conditions . The CD spectrum of this complex resembled that of poly(I).poly(C) . The effect of the fluorine atom at the 2'-position on thermal stability of polynucleotides is discussed.

Cell, 1978 Sep, 15(1), 151 - 62
Sea urchin nuclei use RNA polymerase II to transcribe discrete histone RNAs larger than messengers; Levy S et al.; RNA transcribed in isolated sea urchin nuclei and assayed by hybridization to histone genes cloned in E . coli contains sequences homologous to each of the five histone genes . Histone RNA is synthesized exclusively from the same DNA strand which is the template in vivo . Synthesis of the histone gene transcripts is sensitive to alpha-amanitin concentrations which inhibit RNA polymerase II activity . The fraction of histone RNA synthesized in vitro is comparable at two developmental stages to the fraction synthesized in vivo . The nuclear histone transcripts contain sequences homologous to spacer DNA regions present between the coding regions of the 6500 base pair (bp) histone gene repeat unit . The transcription of spacer sequences was demonstrated by hybridization of the nuclear transcripts to subcloned spacer DNA . Although the bulk of the RNA transcripts are greater than 2000 bases long, the histone-specific transcripts are of discrete sizes ranging from 100 bases to about 1100 bases long . Each histone gene hybridizes with at least one of the larger transcripts and with a different subset of smaller RNAs . We do not detect any giant polycistronic transcript spanning the entire histone repeat unit.

Acta Diabetol Lat, 1978 Sep-Dec, 15(5-6), 313 - 8
Emphysematous pyelonephritis and perinephric gas in a diabetic; Samantray SK; A case of emphysematous pyelonephritis with perinephric gas is presented . The patient was an elderly female diabetic and in addition had a subphrenic abscess as a complication of EPPG . Diabetes was not under control and E . coli was the sole pathogen . As the patient did not respond to conservative treatment, nephrectomy and drainage of subphrenic abscess were done and the patient improved rapidly.

Mol Biol (Mosk), 1978 Sep-Oct, 12(5), 980 - 7
{Specific cleavage of glycosylyl denatured DNA of T2 and T4 phages adjacent to the oligothymidilic or oligoadenylic sequences}; Grineva NI et al.; A method of complementarily directed alkylation with following elimination of the alkylated bases and with DNA cleavage at apurinic sites was used for specific fragmentation of glucosylyl DNA of T2 and T4 phages . It was shown that denatured glucosylyl T2 and T4 DNA's are modified by alkylating derivatives of hexaadenylate and heptauridylilate . The extent of alkylation reached the maximum and then stopped . The extent of elimination and chain cleavage corresponded to that of alkylation . Treatment of DNA after alkylation with (Ap)5ARCl under condition of saturation at 20 degrees gives 572 +/- 28 fragments from T4 DNA with 200--25,000 nucleotides long and 578 +/- 33 fragments from T2 DNA . Alkylation under condition of DNA saturation with (Ap)5ARCl at 40 degrees leads to 138 +/- 15 fragments from T4 DNA and 170 +/- 16 fragments from T2 DNA . Characteristics of the fragments obtained are given.

Mol Biol (Mosk), 1978 Sep-Oct, 12(5), 1096 - 104
{Role of the lysine residues in the phenylalanyl-tRNA synthetase substrates interaction}; Gorshkova II et al.; The effect of 2,4-pentandione on the activity of phenylalanyl-tRNA synthetase (Phe-RSase) from E . coli MRE-600 was investigated . It was shown that modification of Phe-RSase with 2,4-pentandione leads to decrease of the aminoacylation rate without an influence on the ATP--{32P}pyrophosphate exchange reaction rate . tRNAPhe protects the enzyme against inactivation . Neither L-Phe and ATP nor the analog fo aminoacyladenylate protects the enzyme against inactivation . There are no changes in Km for amino acid and ATP in the aminoacylation reaction after modification while Km for tRNAPhe decreases three times . The dissociation constant of Phe-RSase: {14C}Phe-tRNA complex increases 4--8 times after modification . It is assumed that there are some lysine residues in Phe-RSase essential for the Phe-RSase-tRNA interaction.

Gene, 1978 Sep, 4(1), 37 - 49
Isolation and analysis of recombinant DNA molecules containing yeast DNA; Petes TD et al.; 2500 recombinant plasmids containing insertions of yeast nuclear DNA have been cloned in Escherichia coli . It can be calculated that about 85% of the yeast genome is represented in this collection . The clones have been characterized by hybridization to purified RNA species . Of the 2000 clones examined, 75 contain insertions of yeast ribosomal DNA, 201 contain insertions of yeast tRNA genes, and 26 contain DNA sequences that are complementary to abundant mRNA species.

Gene, 1978 Sep, 4(1), 25 - 36
Amplification of the respiratory NADH dehydrogenase of Escherichia coli by gene cloning; Young IG et al.; A relatively simple method has been used to clone the gene coding for the respiratory NADH dehydrogenase (NADH-ubiquinone oxidoreductase) of Escherichia coli from unfractionated chromosomal DNA . The restriction endonucleases EcoRI, BamI and HindIII were used to construct three hybrid plasmid pools from total E . coli DNA and the amplifiable plasmids pSF2124 and pGM706 . Three different restriction endonucleases were used to increase the chances of cloning the ndh gene intact . Mobilization by the plasmid F was used to transfer the hybrid plasmids into ndh mutants and selection was made for Apr and complementation of ndh . DNA fragments complementing ndh were isolated from both the EcoRI and HindIII hybrid plasmid pools . The strain carrying the hybrid plasmid constructed with EcoRI produced about 8--10 times the normal level of the respiratory NADH dehydrogenase in the cytoplasmic membrane . Treating the cells with chloramphenicol to increase the plasmid copy number allowed the level of NADH dehydrogenase in the membrane to be increased to 50--60 times the level in the wild type . The results indicate the potential of gene cloning for the specific amplification of particular proteins prior to their purification.

Ecotoxicol Environ Saf, 1978 Sep, 2(2), 133 - 41
Potential toxicity of materials used for home insulation; Morin NC et al.; The two aqueous solutions used for production of residential home insulation by the so-called urea-formaldehyde process were tested for their ability to react with cellular macromolecules . One of the components (the catalyst-surfactant) changed the apparent molecular weight of isolated DNA and increased its rate of attachment to bacterial and animal cells . The other component (the formaldehyde-urea resin) showed both these activities, especially following its exposure to mouse or rat liver extracts (postmitochondrial supernatants) . Actively growing HeLa cells exposed to the catalyst-surfactant solution and then extracted with phenol yielded diminishing amounts of DNA, suggesting the formation of strong bonds to other cellular macromolecules, most likely to proteins . Formation of complexes between nucleic acids and proteins, enhanced cellular binding of DNA, and decreased extractability of DNA from growing cells exposed to chemicals have been found in separate studies to correlate with carcinogenic activity of various substances . Since a significant number of buildings will be insulated with this urea-formaldehyde foam and since such foam is also used in agriculture on crops, appropriate precautions should be taken to limit human exposure to the component materials.

Res Vet Sci, 1978 Sep, 25(2), 188 - 92
Tolerance breaking by lymphocyte activating factor induced by Escherichia coli O138 lipopolysaccharide from homologous macrophages; Allan D et al.; Following an antigenic dose of 10 microgram or a tolerogenic dose of 200 microgram of Escherichia coli O138 lipopolysaccharide (LPS), BALB/c mice were examined on day 14 for percentages of theta-bearing cells . A considerable increase in T cells was noticed in lymphocytes from tolerant draining lymph nodes, and furthermore these cells did not possess receptors for LPS when tested for rosette inhibition . However, when the supernatant from 1 X 10(7) macrophages, pretreated with 150 microgram LPS, was given to tolerant mice on day 7, by day 14 tolerance was found to be broken, anti-LPS IgG was present in circulation and the draining lymph node contained T cells specifically committed to LPS . The change from suppressor to helper T cell activity is discussed in relation to enhancement of the immune response.

Res Vet Sci, 1978 Sep, 25(2), 168 - 72
In vivo studies on suppressor lymphocyte activity following administration of Escherichia coli O138 lipopolysaccharide; Allan D et al.; Evaluation of Escherichia coli vaccines used in veterinary practice usually relates to antibody formation and neglects the essential characteristics of cell function leading to this end . This paper attempts to investigate the cellular responses to E coli O138 lipopolysaccharide (LPS) administered subcutaneously in a dose range of 1 microgram to 200 microgram . Rosette-forming cell responses in the draining lymph node varied from antigenic at 10 microgram to tolerogenic at 200 microgram . The tolerogenic dose also caused a marked mitogenic response as can be seen by a fourfold increase in total lymph node cells . Fractionation of normal or LPS-responding, or LPS-tolerised lymph node cells into B cell-rich and T cell-rich fractions was carried out and these were adoptively transferred simultaneously with an antigenic dose of sheep erythrocytes (SRBC) into syngeneic recipient mice . Suppressor activity of the anti-SRBC response was found after transfer of 1 X 10(6) normal B cell fractions, 1 X 10(6) tolerised B cell fractions and 1 X 10(6) tolerised T cell fractions . LPS-antigenically stimulated lymph node cell fractions had no suppressor effect but when given with Freund's complete adjuvant ensuing T cell-rich fractions produced immunosuppression in recipient mice . The significance of these findings is discussed in relation to polyclonal B cell activation, helper and suppressor T cells, and possible feedback mechanisms between interacting subpopulations of lymph node cells.

J Biochem (Tokyo), 1978 Sep, 84(3), 681 - 6
Identification of host-derived subunits of phage SP RNA-dependent RNA polymerase (SP replicase); Mori H et al.; Phage SP RNA-dependent RNA polymerase (SP replicase) was purified from Escherichia coli infected with RNA phage SP . The enzyme was found to be composed of four non-identical polypeptides, i.e . subunits I, II, III, and IV and molecular weights of 74,000, 69,000, 47,000, and 36,000 daltons, respectively . As in the case of phage Qbeta replicase, the largest polypeptide is identical with the ribosomal protein S1, and subunits III and IV with polypeptide chain elongation factors EF-Tu and EF-ts, respectively. . This is based on the behaviour of the subunits on SDS-polyacrylamide gel electrophoresis, isoelectric focusing and immunological cross-reaction . Subunits I, III, and IV of SP replicase are derived from the host cell, while subunit II is coded by phage RNA genome . The striking coincidence of the composition and entity of the structural components of SP replicase with those of Qbeta replicase may indicate the structural and functional requirements of host-derived polypeptides in RNA replicase . The binding activity of S1 (in 70S ribosome comples) to poly (U) is retained in SP replicase complex . In contrast, the GDP binding activity of EF-Tu is masked in SP replicase . It is concluded that S1 is required functionally whereas EF-Tu.EF-Ts are required structurally in RNA replicase.

J Biochem (Tokyo), 1978 Sep, 84(3), 673 - 9
Hydrogen-dependent growth of Escherichia coli in anaerobic respiration and the presence of hydrogenases with different functions; Yamamoto I et al.; E . coli K10 was found to grow anaerobically on molecular hydrogen by reducing nitrate, fumarate, and trimethylamine N-oxide when peptone was added to the culture medium . Molar growth yields based on consumed hydrogen estimated from the amounts of reduction products were all 7.8 g cells/mol, suggesting that 1 mol of ATP was produced in the oxidation of 1 mol of hydrogen . Hydrogenase activity measured in terms of hydrogen evolution was several times higher in cells grown on glucose than in cells grown on hydrogen in the presence of fumarate and trimethylamine N-oxide, while hydrogenase activity measured in terms of hydrogen uptake was unchanged in both cases . The ratio of hydrogenase activities measured in terms of hydrogen uptake and evolution was also high in the extract and centrifugal fractions from cells grown in hydrogen . The soluble fraction and trypsin digest of the precipitate at 100,000 X g were subjected to polyacrylamide disc gel electrophoresis and hydrogenase bands were stained by reduction of benzyl viologen with hydrogen and by oxidation of reduced methyl viologen . The resulting patterns suggest that multiple forms of hydrogenase are present and that the amounts of forms functioning in hydrogen evolution were greatly decresed in cells grown on hydrogen in the presence of acceptors.

Genetika, 1978 Sep, 14(9), 1521 - 9
{Molecular cloning of the structural genes of the Escherichia coli deo-operon in plasmid RSF2124}; Mironov AS et al.; A specialized phage lambda ddeo carrying the deo operon of Escherichia coli is analyzed by exposing the DNA to the specific restriction endonucleases EcoRI and BamHI . Using the lambda ddeo DNA fragment, obtained by digestion with BamHI and plasmid RSF2124 as a vehicle, the hybrid plasmid pAM1 carrying all the genes of the deo operon is constructed and cloned in E . coli cells . It is shown that the activity of thymidine phosphorylase in the strain AM061, which contains hybrid plasmid pAM1 is 30-fold greater than that in strains of E . coli with chromosomal localization of the deo operon.

Genetika, 1978 Sep, 14(9), 1503 - 12
{Cloning chloroplast DNA in escherichia coli . I . Construction and selection of recombinant plasmids containing fragments of pea chloroplast DNA}; Andrianov VM et al.; Fragments produced by digestion of Pisum sativum chloroplast DNA with EcoRI were examined by agarose gel electrophoresis . These EcoRI-fragments were joined in vitro to Apr-ColE1 RSF2124 plasmid and cloned in Escherichia coli . Methods of molecular cloning of plasmid chimeras by success gradient centrifugation and repeated transformation and selection of recombinant plasmids using mytomicin C were used for cloning hybrid plasmids with various EcoRI fragments of pea chloroplast DNA has been obtained.

Exp Hematol, 1978 Sep, 6(8), 661 - 72
The marrow colony forming cell and serum colony stimulating factor of the chicken; Dodge WH et al.; Marrow cells of the chicken produced colonies in semisolid media . Developing colonies consisted of granulocytes, macrophages or a mixture of these two cell types . The granulocyte-macrophage CFC was nonadherent . An adherent 'CFC' was also present and it differed in several ways from the nonadherent CFC: (a) clones contained only macrophages, (b) they contained a core of nonrefractile cells, (c) their appearance was delayed 1-2 weeks, (d) they were unaffected by the presence of erythrocytes and (e) the efficiency of cloning was increased but the percentage of clones able to produce 50 or more cells was markedly decreased, i.e., the cluster/colony ratio was increased . The growth of both colony types was strictly dependent on the presence of CSF . Data obtained from dose-response studies on unfractionated marrow indicated that clusters and colonies were derived from single cells . The CSF of chicken serum yielded sigmoid dose-response curves when tested on marrow cells . Calf serum could not support cluster or colony formation when tested alone but it did have an enhancing effect on the CSF of chicken serum . Levels of serum CSF were increased by injecting chickens with bacterial endotoxin . This phenomenon occurred with five chicken lines tested, but certain chickens of the Kimber line did not respond to endotoxin with elevated levels of CSF.

Eur J Biochem, 1978 Sep 1, 89(2), 531 - 41
A study of the thermal unfolding of Escherichia coli phenylalanine transfer RNA by chemical modification at elevated temperatures; Goddard JP et al.; Escherichia coli tRNAPhe was modified by 3 M sodium bisulphite pH 6.0 for 24 h in the temperature range 25 degrees C (x 5 degrees C) to 55 degrees C and in the absence of added magnesium ions . The sites and extents of conversion of cytidines to uridine occurring at each temperature were determined by fingerprinting . The new sites of cytidine modification found at higher reaction temperatures were assumed to arise from breakage of secondary and tertiary structure hydrogen bonds involving cytidine residues . From these data, we conclude that hydrogen bonds within the 'complex core' of the tRNA (including the base pairs G-10 . C-25, C-11 . G-24 and C-13 . G-21 within the dihydrouridine stem and the tertiary structure base pair G-15 . C-48 melt at a lower temperature than the tertiary structure hydrogen bonds between G-19 in the dihydrouridine loop and C-56 in the TpsiC loop.

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