Escherichia coli

Biochim Biophys Acta, 1977 Nov 1, 470(3), 453 - 64
Proline transport activity in Escherichia coli membrane vesicles of different buoyant densities; van Heerikhuizen H et al.; Cytoplasmic membrane vesicles prepared by lysis of Escherichia coli W 3110 spheroplasts in a French press at 0 degrees C are heterogeneous with respect to density due to membrane protein aggregation as a result of lateral phase separation of membrane phospholipids and to the presence of more or less outer membrane . These different vesicle classes can be separated on isopycnic density gradients . Assays for various membrane-associated functions show that the membranes differ not only with respect to density and structure but also with respect to function . The proline transport system (as detected by uptake experiments with the artificial electron donor ascorbate-phenazine methosulfate) shows maximal activities in membrane fractions that have considerably higher densities than the normal cytoplasmic membrane . This is always the case, whether vesicles are isolated from membranes that exhibit a temperature-induced protein aggregation or not . A correlation between high proline transport activity and the presence of vesicles with double membranes (consisting of outer and inner membrane) has been established . The possibility that the outer membrane protects the transport system in the cytoplasmic membrane during the isolation of vesicles is discussed.

J Infect Dis, 1977 Nov, 136(5), 640 - 8
A rabbit model of diarrhea due to invasive Escherichia coli; Cantey JR et al.; A nonpiliated strain of invasive Escherichia coli of human origin (HInvEC) was given to rabbits (weight, 0.7-1.1 kg) in doses ranging from 1.5 X 10(8) to 2.5 X 10(10) bacteria . E . coli strain HInvEC colonized the ileum, cecum, and colon in large numbers for one to three days and produced diarrhea in 91 ((58%) of the 156 rabbits . A dose of 2.5 X 10(10) bacteria reliably and repeatedly elicited diarrheal disease in 80% of the animals . The acute pathohistology as determined by light microscopy, transmission electron microscopy, and immune fluorescent microscopy was manifest in the distal ileum, cecum, and colon . Prominent findings included mucosal ulcers, bacterial invasion of the lamina propria, and a polymorphonuclear infiltrate in the lamina propria . Diarrhea due to strain HInvEC was followed by a rise in the titer of serum antibody to O antigen of E . coli.

J Infect Dis, 1977 Nov, 136(5), 633 - 9
Immunization against retrograde pyelonephritis . III . Vaccination against chronic pyelonephritis due to Escherichia coli; Brooks SJ et al.; Vaccination with formalin-treated cells of Escherichia coli serotype O6 protected against unilateral retrograde pyelonephritis due to E . coli O6 in rats with partial ureteral obstruction . This protection was manifested not only by less parenchymal destruction and shrinkage of the pyelonephritic left kidney, but also by less secondary pyelonephritis and compensatory hypertrophy in the opposite right kidney . Vaccinated rats eliminated E . coli from the kidney more rapidly, but even when infection persisted in the kidney, the chronic pyelonephritis was less severe in vaccinated rats . High levels of antibody to E . coli lipopolysaccharide were found in vaccinated animals and may have contributed to protection . These results raise the question of whether vaccination ought to be considered for patients predisposed to chronic bacterial pyelonephritis.

J Immunol, 1977 Nov, 119(5), 1846 - 8
B memory cells in the thymus: part of the pool of potentially circulating memory cells; Benner R et al.; Immunization of mice with sheep red blood cells (SRBC) or Escherichia coli lipopolysaccharide (LPS) induces the appearance of B memory cells in the thymus . In this paper the origin of these B memory cells was investigated . Therefore, mice primed with either SRBC or LPS 6 months previously and nonprimed mice were joined for parabiosis . Four weeks later the parabiotic mice were separated from each other . Another 3 weeks later thymus cells from the primed and nonprimed mice were transferred separately into lethally irradiated mice in order to determine the adoptive PFC response . It was found that the 4-week period of parabiosis could account for the appearance of a distinct population of B memory cells in the thymus of the nonprimed mice . This result suggest that the B memory cells which appear in the thymus belong to the pool of potentially circulating memory cells.

J Bacteriol, 1977 Nov, 132(2), 718 - 22
Visualization of ribosomal ribonucleic acid synthesis in a ribonuclease III-Deficient strain of Escherichia coli; Hofmann S et al.; Transmission electron microscopy was used to examine active ribosomal ribonucleic acid (rRNA) genes in two strains of Escherichia coli: N2077, deficient in the enzyme responsible for proper cleavage of the 16S sequence from the elongating nascent rRNA transcript; and N2076, functional in ribonuclease (RNase) III activity, yet otherwise isogenic to N2077 . In the strain with wild-type RNase III, double gradients corresponding to a pattern of 16S-cleavage-23S transcription were observed . However, the RNase III-deficient strain exhibited a single ribosomal gradient of approximately the same length as the combined 16S-23S gradients of the wild-type strain . When the rRNA genes were somewhat loosely packed with RNA polymerases, a few of the nascent chains in the ribosomal matrixes of the RNase III-deficient strain were cleaved, but most appeared to be unprocessed . The completed, uncleaved transcripts originating from these gradients are believed to be 30S rRNA molecules recently characterized by biochemical probes.

J Bacteriol, 1977 Nov, 132(2), 657 - 65
Localization of proteins controlling motility and chemotaxis in Escherichia coli; Ridgway HG et al.; Flagellar proteins controlling motility and chemotaxis in Escherichia coli were selectively labeled in vivo with {35S}methionine . This distribution of these proteins in subcellular fractions was examined by sodium dodecyl sulfatepolyacrylamide gel electrophoresis and autoradiography . The motA, motB, cheM, and cheD gene products were found to be confined exclusively to the inner cytoplasmic membrane fraction, whereas the cheY, cheW, and cheA (66,000 daltons) polypeptides appeared only in the soluble cytoplasmic fraction . The cheB, cheX, cheZ, and cheA (76,000 daltons) proteins, however, were distributed in both the cytoplasm and the inner membrane fractions . The hag gene product (flagellin) was the only flagellar protein examined that copurified with the outer lipopolysaccharide membrane . Differences in the intracellular locations of the che and mot gene prodcuts presumably reflect the functional attributes of these components.

J Bacteriol, 1977 Nov, 132(2), 549 - 54
Further mapping of several membrane lipid biosynthetic genes (fabC, fabB, gpsA, plsB) of Escherichia coli; Clark D et al.; New genetic mapping data on several loci involved in membrane lipid synthesis are reported . We demonstrated that the lesion designated fabC by Broekman and Hoeckstra (Mol . Gen . Genet . 124:65-67, 1975) is a fabB mutation . In the course of this work, the orientation of the pdxB and fabB loci was determined . The order of the loci is fabB pdxB purF . We also report cotransduction between the gpsA and cysE loci and show that the order of these markers is mtl cysE gpsA . Cotransduction between the plsB and kdgK loci was also sought . Despite extensive experiments, we were unable to detect cotransduction between these loci . In addition, we were unable to detect cotransduction among several markers in region 46 to 48 min of the map.

J Bacteriol, 1977 Nov, 132(2), 532 - 40
Evidence for a complex of three beta-oxidation enzymes in Escherichia coli: induction and localization; O'Brien WJ et al.; The enzymes for beta-oxidation of fatty acids in inducible and constitutive strains of Escherichia coli were assayed in soluble and membrane fractions of disrupted cells by using fatty acid and acyl-coenzyme A (CoA) substrates containing either 4 or 16 carbon atoms in the acyl moieties . Cell fractionation was monitored, using succinic dehydrogenase as a membrane marker and glucose 6-phosphate dehydrogenase as a soluble marker . Acyl-CoA synthetase activity was detected exclusively in the membrane fraction, whereas acyl-CoA dehydrogenase, 3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities that utilized both C4 and C16 acyl-CoA substrates were isolated from the soluble fraction . 3-Hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and 3-ketoacyl-CoA thiolase activities assayed with both C4 and C16 acyl-CoA substrates co-chromatographed on gel filtration and ion-exchange columns and cosedimented in glycerol gradients . The data show that these three enzyme activities of the fad regulon can be isolated as a multienzyme complex . This complex dissociates in very dilute preparations; however, in those preparations where the three activities are separated, the fractionated species retain activity with both C4 and C16 acyl-CoA substrates.

J Bacteriol, 1977 Nov, 132(2), 526 - 31
Regulation of fatty acid synthesis during the cessation of phospholipid biosynthesis in Escherichia coli; Nunn WD et al.; In 1975, Cronan et al . (J . Biol . Chem . 250:5835-5840) reported that free fatty acids accumulated during glycerol starvation of an Escherichia coli glycerol auxotroph . On the basis of labeling experiments showing significant incorporation of {14C}acetate into the fatty acid fraction of glycerol-starved cells, these authors concluded that fatty acid synthesis proceeded normally in the absence of phospholipid synthesis . Since these findings might have been due to an increase in the intracellular specific activity of the {1-14C}acetyl coenzyme A pool of the glycerol-starved cells, we reexamined the effect of glycerol starvation on fatty acid synthesis . We found that (i) the incorporation of 3H2O and/or {2,3-14C}succinate into the fatty acid fraction of glycerol auxotrophs is severely reduced during starvation, (ii) the incorporation of {1-14C}acetate into the lipid fraction of an acetate-requiring glycerol auxotroph is inhibited by 95% during glycerol starvation, and (iii) the accumulation of fatty acids, as measured by microtitration, in glycerol-starved cells is less than 10% that of glycerol-supplemented cells . These results indicate that fatty acid synthesis is inhibited in the absence of phospholipid synthesis of E . coli.

J Bacteriol, 1977 Nov, 132(2), 453 - 61
Regulation of aromatic amino acid transport systems in Escherichia coli K-12; Whipp MJ et al.; The regulation of the aromatic amino acid transport systems was investigated . The common (general) aromatic transport system and the tyrosine-specific transport system were found to be subject to repression control, thus confirming earlier reports . In addition, tryosine- and tryptophan-specific transport were found to be enhanced by growth of cells with phenylalanine . The repression and enhancement of the transport systems was abolished in a strain carrying an amber mutation in the regulator gene tyrR . This indicates that the tyrR gene product, which was previously shown to be involved in regulation of aromatic biosynthetic enzymes, is also involved in the regulation of the aromatic amino acid transport systems.

J Bacteriol, 1977 Nov, 132(2), 411 - 8
Lysozyme-promoted association of protein I molecules in the outer membrane of Escherichia coli; Chopra I et al.; Incubation of whole envelopes prepared from sonically oscillated Escherichia coli K-12 cultures with lysozyme in vitro resulted in the appearance of a protein species with an apparent molecular weight double that of outer membrane protein I . Similar dimers were also detected in purified outer membranes and whole envelopes from lysozyme-induced spheroplasts of E . coli K-12 . This was confirmed by two-dimensional electrophoresis in which the dimers were resolved in the second dimension to run as single polypeptides of protein I . Formation of dimers was correlated with peptidoglycan degradation, but the ability of protein I molecules to associate may vary between strains of E . coli, since dimers were found only in outer membranes from E . coli W7 . We suggest that extensive degradation of peptidoglycan leads to nonspecific formation of protein I aggregates, but that these aggregates do not occur in vivo.

J Bacteriol, 1977 Nov, 132(2), 392 - 7
Intracellular localization and effects on cell division of a plasmid blocked in deoxyribonucleic acid replication; MacQueen HA et al.; Cell division in a uvr mutant of Escherichia coli is suppressed by introdcution into the cell of an ultraviolet-irradiated plasmid . Autoradiography was used to determine the localization of the incoming plasmid and the segregation pattern of the host chromosomes.

Clin Chem, 1977 Nov, 23(11), 2080 - 4
Detection of endotoxins in human blood and plasma . An improved in-vitro pyrogen test; Nandan R et al.; We describe an improved in-vitro procedure for detection of endotoxin in human blood and plasma by use of Limulus amoebocyte lysate . Increasing concentrations of Escherichia coli endotoxin added to a constant amount of the lysate cause a proportional increase in protein precipitated by the endotoxin . By measuring the amount of protein precipitated, it was possible to determine the equivalent E . coli endotoxin concentration in unknown samples, when samples were run with E . coli endotoxin standards and negative controls . The E . coli endotoxin, present in human whole blood and platelet-rich plasma, failed to react with the lysate . However, the concentration of endotoxin in whole blood and platelet-rich plasma could be measured with this Limulus test after lysing the platelets to release the endotoxin and subsequently removing the inhibitory proteins by chloroform precipitation . With this procedure it was possible accurately and repeatedly to determine E . coli equivalent endotoxin concentrations as low as 195 ng per liter of whole blood or 49 ng per liter of platelet-rich plasma.

Biochemistry, 1977 Nov 1, 16(22), 4934 - 9
Repair of nitrous acid damage to DNA in Escherichia coli; Da Roza R et al.; A number of mutant strains of Escherichia coli have been examined for their sensitivity to nitrous acid and in some instances to methylmethanesulfonate . All ung- mutants tested are abnormally sensitive to nitrous acid . Since the ung mutation is phenotypically expressed as a defect in uracil DNA glycosidase, this observation supports the contention that treatment of cells with nitrous acid causes deamination of cytosine to uracil . In addition the observed sentitivity indicates that the ung gene is involved in the repair of uracil in DNA . Studies with other mutants suggest that both exonuclease III and DNA polymerase I of E . coli are involved in the repair of nitrous acid damage in vivo.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 4900 - 4
Sequence of an oligonucleotide derived from the 3' end of each of the four brome mosaic viral RNAs; Dasgupta R et al.; A 3'-terminal oligonucleotide fragment, 161 bases long, can be obtained from each of the four brome mosaic virus RNAs by means of nuclease digestion . Like the four intact brome mosaic virus RNAs, each fragment accepts tyrosine in a reaction catalyzed by wheat germ aminoacyl-tRNA synthetase . The complete nucleotide sequence of the RNA 4 fragment has been determined by use of standard radiochemical methods . Comparative data for the fragments from RNAs 1, 2, and 3 show that they have nearly the same sequence as the RNA 4 fragment . The eight bases adjacent to the 3' terminus of the RNA 4 fragment are identical in sequence to the eight terminal bases of tyrosine tRNA from Torula utilis and eleven interior bases are identical in sequence to eleven bases encompassing the anticodon region of tyrosine tRNA from Saccharomyces cerevisiae, T . utilis, and Escherichia coli . Nevertheless, reasonable base-pairing schemes yield, at best, a distorted cloverleaf secondary structure.

Appl Environ Microbiol, 1977 Nov, 34(5), 604 - 6
Agar plate screening procedure for cyclic adenosine 3',5'-monophosphate and inhibitors of cyclic nucleotide phosphodiesterase; Somers PJ et al.; A procedure is described for the semiquantitative measurement of cyclic adenosine 3',5'-monophosphate (cAMP) and detection of inhibitors of cAMP phosphodiesterase by an agar plate test . The assay organism was an adenyl cyclase-deficient mutant derived from Escherichia coli HfrH . In the presence of an acid base indicator, acid production from barbohydrate metabolism was observed as a yellow zone around filter paper disks containing cAMP . Since yellow zone formation reflects the presence of cAMP, a phosphodiesterase inhibitor can be detected indirectly by the presence of a yellow zone on assay plates from a reaction mixture of an inhibitor, phosphodiesterase, and cAMP . Three known cyclic nucleotide phosphodiesterase inhibitors were active against beef brain phosphodiesterase in this system.

Vet Pathol, 1977 Nov, 14(6), 567 - 81
Pathology of adenoviral infection in turkeys (Meleagris gallopavo) with respiratory disease and colisepticemia; Cheville N et al.; Nuclear inclusion bodies typical of the adenovirus group were widespread in in the spleen and other tissues of 8-week-old turkeys with severe respiratory disease and concomitant evidence of colisepticemia . Adenoviral virions were seen in affected nuclei of splenic tissue and in negatively stained preparations of ground spleen . In splenic tissue, inclusions were most prominent in reticular cells and macrophages in the periarterial lymphoid sheaths, the red pulp and the marginal zones of the periarteriolar reticular sheaths . Marked reticuloendothelial hyperplasia, lymphoid atrophy and granulocytic splenitis characterized the splenic changes . There were inclusions in the respiratory tract, intestinal tract, liver, kidney and pancreas . Inoculation of young turkeys, especially when immunosuppressed, resulted in evidence of infection and respiratory disease . The viruses produced cytopathic changes in primary turkey kidney cell cultures but did not affect embryonating chicken eggs . Concentrated viral suspensions induced precipitin lines in agar gel immunodiffusion tests with known antisera against known turkey adenoviruses but did not show an antigenic relationship to chicken adenoviruses.

J Lipid Res, 1977 Nov, 18(6), 777 - 80
A rapid and sensitive radiochemical assay for phosphatidic acid phosphohydrolase activity; Flynn TJ et al.; A technique is described for the radiochemical assay of phosphatidic acid phosphohydrolase activity in rat brain . Radiochemically pure 32P-labeled phosphatidic acid of known specific radioactivity and structure, which was biosynthesized in vitro by the diacylglycerol kinase of E . coli, was used as the substrate . As little as 5 microgram of microsomal or mitochondrial protein can be used for the assay, and product formation in the picomole range can be determined accurately . This procedure should be useful in situations where only limited amounts of tissue are available.

Infect Immun, 1977 Nov, 18(2), 352 - 5
New test for endotoxin potency based upon histamine sensitization in mice; Bergman RK et al.; The results of a test of endotoxic potency based upon the development of histamine hypersensitivity in mice were compared with the results obtained by testing the same materials for pyrogenicity in rabbits and lethality for chicken embryos (CELD50) . The results of the histamine hypersensitization test (HHT) correlated well with those of the other two tests . The sensitivity of the HHT was about the same as that of the CELD50 assay . The HHT may provide a relatively inexpensive, fast, and reliable assay method for endotoxin laboratories that do not have the facilities for the more elaborate assays.

Arch Ophthalmol, 1977 Nov, 95(11), 2057 - 61
Herpes simplex uveitis in immune rabbits . Priming effect of nonherpetic uveitis; Oh JO; Systemic immunization of rabbits with herpes simplex virus (HSV) had two opposite effects on the outcome of subsequent efforts to produce primary HSV uveitis, the difference depending on whether or not the rabbits had had nonherpetic uveitis before the HSV challenge . In normal eyes, systemic immunization with HSV provided complete protection against the production of primary uveitis by an intraocular injection of HSV; but in eyes that had had a bout of experimentally induced nonherpetic uveitis before the challenge, the same systemic immunization was not protective . In these eyes, an immune-mediated uveal inflammation developed . Nonherpetic uveitis had apparently "primed" the eyes of the HSV-immune rabbits for subsequent immune-mediated HSV uveitis.

J Med Chem, 1977 Nov, 20(11), 1522 - 5
Synthesis and biological activity of two metabolites of 1-methyl-5-(1-methylethyl)-2-nitro-1 H-imidazole, an antiprotozoal agent; Cavalleri B et al.; 5-(-Hydroxyl-1-methylethyl-)-1-methyl-2-nitro-1 H-imidazole (6) and 5-(1,2-dihydroxyl-1-methylethyl)-1-methyl-2-nitro-1 H-imidazole (9) are the principal metabolites found in urines of animals (mice, rats, and dogs) treated with 1-methyl-5-(1-methylethyl)-2-nitro-1 H-imidazole (1), an effective antitrichomonas agent . These two metabolites have been synthesized . Compound 6 was found to be less toxic than the parent compound 1 and to possess essentially the same activity against Trichomonas vaginalis in experimental infections . Compound 9 showed a low degree of in vivo activity.

Biochem J, 1977 Nov 1, 167(2), 497 - 9
Inhibition of the membrane-bound adenosine triphosphatase of Escherichia coli by dicyclohexylcarbodi-imide; Feinstein DL et al.; The inhibition of the membrane-bound adenosine triphosphatase of Escherichia coli by DCCD (dicyclohexylcarbodi-imide) is studied under conditions of varying KCl concentration . An increase in K+ concentration and in other cations causes an increase in the DCCD sensitivity of the enzyme, as well as significant changes in the kinetic parameters.

Mol Biol (Mosk), 1977 Nov-Dec, 11(6), 1357 - 76
{Peptidyltransferase center of ribosomes . Structure and relationship to other ribosomal functions}; Kukhanova MK et al.; Structural analysis of the ribosomal peptidyl transferase center using model substrates "minimal" peptide acceptors and donors is reported in the present work . Recent data on the ribosomal proteins and rRNA organizing the peptidyl transferase center and other functional centers of the large ribosomal subunits are given and the know facts about the catalytic mechanism of the peptide bond formation are considered . An analysis of the interaction of the peptidyl transferase center and the centers binding the cytoplasmic translocation factors and stringent-factor (for E . coli ribosome) is presented; a possible contribution of the peptidyl transferase center ot the translocation is discussed.

J Biol Chem, 1977 Oct 25, 252(20), 7344 - 54
Insertion of DNA carrying ribosomal protein genes of Escherichia coli into Charon vector phages; Williams BG et al.; DNA fragments from lambdaspc1 and lambdafus2, carrying ribosomal protein genes from Escherichia coli, were inserted into lambda phage vectors Charon 3 and Charon 4 . Eight of the resulting clones were characterized by agarose gel electrophoresis of EcoRI digests, analytical CsCl equilibrium centrifugation, and electron micrographic analysis of heteroduplexes . In each case, the identity, order, and orientation of each cloned fragment was determined . In all, 8 of the 12 EcoRI fragments of lambdafus2 were cloned in various arrangements . In the accompanying paper, genes for 15 ribosomal and related proteins and three bacterial promoters were detected in these phages . In addition, four of the hybrid phages carried fragments of lambda-DNA including the phage origin of replication (ori), the late promoter, PR', and the cohesive ends (cos site) in both orientations . The latter phages yield a circularly permuted collection of DNA molecules.

J Biol Chem, 1977 Oct 25, 252(20), 7337 - 43
Organization of ribosomal protein genes of Escherichia coli as analyzed by polar insertion mutations; Jaskunas SR et al.; Several mutants of lambdaspc1 and lambdafus3 have been isolated carrying DNA insertion elements that were selected for their ability to reduce the expression of the spc gene . The sizes and locations of the insertions on the phage genomes were determined by heteroduplex analysis . They were found to be located at different positions in the Spc transcription unit . The effect of these insertions on the expression of the ribosomal protein genes carried by these phages in ultraviolet light-irradiated bacteria was investigated . The insertions at intermediate positions in the transcription unit reduced the expression of some of the genes in the unit but not others . Assuming that the genes whose expressions were reduced are distal to the insertion, it was possible to determine the relative position of most of the genes in the unit . The results indicate the order of genes in the Spc transcription unit is: promoter, L14, L24, L5, S14, S8, L6, L18, (S5, L15, L30).

J Biol Chem, 1977 Oct 25, 252(20), 7323 - 36
Identification and organization of ribosomal protein genes of Escherichia coli carried by lambdafus2 transducing phage; Jaskunas SR et al.; We describe the isolation of lambdafus2, which carries bacterial DNA from the str-spc region of the Escherichia coli chromosome . Genes for 27 ribosomal proteins were found on the genome of this transducing phage by identifying the ribosomal proteins whose synthesis was stimulated after infection of UV-irradiated bacteria . These were genes for S3, S4, S5, S7, S8, S10, S11, S12, S13, S14, S17, S19, L2, L3, L4, L5, L6, L14, L15, L16, L17, L18, L22 L23, L24, L29, and L30 . Subsets of these genes were identified on the genomes of the phages lambdaspc1, lambdaspc2-delta 9, and lambdaspc2-delta16, all of which carry parts of the bacterial DNA present on lambdafus2 . From the known structures of these phage genomes, it has been possible to determine the relative order of many of these genes on the lambdafus2 genome and thus on the E . coli chromosome . Our evidence also suggests that the genes for S3, S17, S19, L2, L4, L16, L22, L23, and L29 are part of a single transcription unit . These results, along with the observations described in the previous and accompanying papers, indicate that the ribosomal protein genes on lambdafus2 are organized into at least four transcription units.

J Biol Chem, 1977 Oct 25, 252(20), 7273 - 8
Role of the 2-amino group of deoxyguanosine in sequence recognition by EcoRI restriction and modification enzymes; Modrich P et al.; The dG residues within the EcoRI recognition sequence of ColE1 DNA have been selectively replaced with dI . Methylation of the altered sequence by the EcoRI modification enzyme is extremely slow as compared with methyl transfer to the natural recognition site . Since the affinity of the modification enzyme for the dI-containing sequence is considerably less than that for the natural sequence, we have concluded that the 2-amino group of dG has an important role in DNA site recognition by this enzyme . In contrast, the altered site is subject to cleavage by EcoRI endonuclease at rates essentially identical with those observed with the natural sequence . These results strongly suggest that the two enzymes utilize different contacts within the EcoRI site and are consisted with our conclusion (Rubin, R . A., and Modrich, P . (1977) J . Biol . Chem . 252, 7265-7272) that the two proteins interact with their common recognition sequence in different ways.

J Biol Chem, 1977 Oct 25, 252(20), 7023 - 30
Role of ATP in removal of psoralen cross-links from DNA of Escherichia coli permeabilized by treatment with toluene; Yoakum GH et al.; Removal of interstrand cross-linked from DNA was examined in Escherichia coli permeabilized by treatment with toluene . Under these conditions, the reaction requires ATP and Mg2+, and the mechanism appears to be similar to that occurring in whole cells . Under optimum conditions, the rate constant was 0.06 min-1 . Genetical, physical, and biochemical analysis of the repair process suggest the following mechanism . In an ATP-dependent reaction, the uvrA and uvrB gene products cleave a phosphodiester bond on the 5' side of one arm of the cross-link, producing a 3'-OH terminus . Subsequently, DNA polymerase I (5'-3' exonuclease activity) makes a second strand cut on the 3' side of the cross-link in the same DNA strand, completing removal of the covalent link between complementary strands . The second reaction did not occur in a uvrD- strain, which had normal levels of DNA polymerizing activity . The uvrD gene may regulate the specificity or activity of the 5'-3' exonuclease of DNA polymerase I in vivo.

Mol Gen Genet, 1977 Oct 24, 155(3), 301 - 7
Synthetic multifunctional proteins: isolation of covalently linked tryptophan synthetase alpha-subunit-lac-repressor-beta-galactosidase chimeras; Heidecker G et al.; Several E . coli mutants were isolated which produce triple chimeras between one of the trp enzymes lac, repressor and beta-galactosidase . The mutants were isolated as TonB- Lac+ derivatives of a phenotypically Lac- TrpR- strain carrying a lac I+ -Z+ fusion on a phi80dlac phage . The phage is integrated into the chromosome in such a way that the lac and the trp genes are transcribed in the same direction . Of a total of 58 candidates 2 TrpA- and 3 Trp- strains produce triple chimeras . The chimeras from the two TrpA- strians were further examined . They consist of tryptophan synthetase alpha-subunit, lac repressor and beta-galactosidase . In crude extracts of these strains the tryptophan synthetase alpha-subunit part can be identified by its ability to aggregate with the beta-subunit since some of the beta-subunit activity can be precipitated with antiserum against beta-galactosidase . Furthermore beta-galactosidase precipitates with antiserum against tryptophan synthetase alpha-subunit . The lac repressor part is able to bind IPTG, but not lac operator DNA in vitro . The beta-galactosidase part is as unaffected as in the original lac repressor-beta-galactosidase chimera . The molecular weights of both chimeras are 175,000 when determined by SDS gel electrophoresis . The chimeras are partially degraded giving rise to fragments of distinct molecular weights.

Mol Gen Genet, 1977 Oct 24, 155(3), 279 - 86
The dependence of postreplication repair on uvrB in a recF mutant of Escherichia coli K-12; Rothman RH et al.; Mutants carrying recF143 or recF144 show wild type levels of host cell reactivation of UV-irradiated lambdavir and wild type rates of excision gap closure in repairing UV damage to their own DNA . The same mutants showed reduced rates of postreplication repair strand joining . When uvrA- recF- or uvrB- recF- strains are tested, postreplication repair strand joining is incomplete or does not occur at fluences above 1 J/m2 . We suggest that there may be a UvrAB and a RecF pathway of postreplication repair or that the repair functions controlled or determined by uvrA uvrB and by recF may be similar . An intermediate in postreplication repair may accumulate in the uvr- recF- strain.

Mol Gen Genet, 1977 Oct 24, 155(3), 287 - 90
Restoration of mutability in non-mutable Escherichia coli carrying different plasmids; Babudri N et al.; N and I group plasmids, which increase methylmethane sulfonate (MMS) mutagenesis in lexA+ strains of E . coli WP2 may be divided into two classes: those restoring part of the mutability of lexA- stains (class I) and those leaving lexA- strains non-mutable (class II) . Almost complete restoration of MMS mutability is obtained by class I plasmids in a partially suppressed lexA rnm strain, while clase II plasmids cause far fewer MMS revertants in this strain than in lexA+ . A pair of class I and II plasmids in lexA- shows a synergistic effect on mutability . These two classes do not coincide with plasmid division into incompatibility groups.

Nature, 1977 Oct 20, 269(5630), 668 - 72
Amino-terminal fragments of Escherichia coli lac repressor bind to DNA; Jovin TM et al.; The N-terminal fragments (residues 1-51 and 1-59) obtained by selective tryptic cleavage of native lac repressor retain the ability to bind DNA . These fragments (headpieces) are monomeric and form complexes which resemble those of tetrameric repressor with non-operator DNA . But, they do not show the high specificity of repressor for operator sequences . The DNA binding has been demonstrated by filter-binding assay as well as in solution using absorption, circular dichroism, and fluorescence measurements.

Microbiol Immunol, 1977 Oct 20, 21(10), 563 - 71
The host-dependent restriction of growth of an RNA coliphage FI; Hirashima A et al.; Phage FIC is a spontaneous host-dependent mutant of phage FI which is classified into the fourth group of RNA Escherichia coli phages (RNA coliphages) . The mutant phage (FIC) grows normally in E . coli strain Q13 (permissive host), but poorly in strain A/lambda (non-permissive host) (9) . Attempts to elucidate the regulatory mechanism of growth of the mutant phage in the non-permissive host revealed the following: (a) growth of the mutant phage was specifically restricted in E . coli strains that have certain suppressor genes for amber mutation; (b) the mutant phage RNA (FIC-RNA) could not produce progeny in the spheroplasts of the non-permissive host; (c) adsorption of the mutant phage to, and penetration of the mutant phage RNA into, the non-permissive host were normal; and (d) biosynthesis of the phage-specific late protein and RNA did not occur in the non-permissive host . Based on these results we conclude that phage FIC is a spontaneous azure-type mutant of the fourth group of RNA coliphage FI.

Mol Gen Genet, 1977 Oct 20, 155(2), 219 - 25
Regulation of the dnaA product in Escherichia coli; Hansen FG et al.; When an E . coli mutant (CRT46, dnaA46), thermosensitive in the initiation of DNA replication, grows at intermediate temperatures its DNA/mass ratio is somewhat lower than normal, but the cells possess an excess of initiation capacity, which can be expressed in the absence of protein synthesis and lead to the accumulation of anomalously high amounts of DNA . A shift-up in temperature causes inhibition of initiation, and at the same time the production of initiation capacity is accelerated . After a shift-down in temperature initiation is released but the production of capacity is inhibited . The initiation capacity is thermolabile . The simplest explanation of these observations is that the dnaA product has a dual role: a positive function as an initiator of replication and a negative control function in its own synthesis.

Mol Gen Genet, 1977 Oct 20, 155(2), 213 - 7
Transformation of Escherichia coli by a specific DNA restriction fragment; Schweitzer SM et al.; Specific transformation of a rifampicin sensitive strain of Escherichia coli to rifampicin resistance has been performed by a single, defined DNA restriction fragment carrying the genetic information for the beta subunit of E . coli RNA polymerase . In this transformation the transforming genetic character has been substituted for the corresponding recipient gene locus by recombination . The value of the described transformation system for locating genetic markers on DNA restriction fragments is discussed in comparison to previously reported in vitro systems.

Mol Gen Genet, 1977 Oct 20, 155(2), 197 - 202
The frequency of P1 transduction of the genes of Escherichia coli as a function of chromosomal position: preferential transduction of the origin of replication; Masters M; The frequencies with which the generalized transducing phage P1 transduced 26 selected markers on the E . coli . chromosome were measured . The frequencies were found to vary relative to argH+ = 1 from a maximum of 6.8 near the origin of replication to a minimum of 0.23 for a marker not far from the terminus . The low frequencies obtained for some markers were shown not to result from poor expression under the selective conditions employed . When plotted as a function of marker position on the chromosome the frequencies were found to exhibit a series of peaks and troughs which correspond to those in gene density noted by Bachmann et al . (1976) . The possible relationship of these results to the structure of the E . coli chromosome and to the mechanism of generalized transduction are discussed.

Mol Gen Genet, 1977 Oct 20, 155(2), 185 - 9
Relation between F, R1, R100 and R144 Escherichia coli K-12 donor strains in mating; Havekes L et al.; E . coli K-12 recipient mutants defective in conjugation with a F donor (ConF- mutants) were tested for recipient ability with donor strains carrying a R1drd19, R100-1 or R144drd3 plasmid . It appeared from these tests that F and R1 donor strains are closely related in mating in that they both, unlike the R100 and R144 donor, use the recipient outer membrane protein pOmpA for the initial steps of the mating process . The isolation of recipient mutants defective in conjugation with a R100 donor (ConR100- mutants) yielded some mutants that were defective in crosses with F, R1 and R100 donors . This result was taken as evidence that F, R1 and R100 donors share some property in their mating interaction with E . coli K-12 recipient strains . A R144 donor is completely different from F, R1 and R100 donors in initial mating interactions with a recipient.

Mol Gen Genet, 1977 Oct 20, 155(2), 153 - 62
Directed integration of an F' plasmid by integrative suppression: isolation of plaque forming lambda transducing phage for the dnaC gene; Iida S; A new approach for isolation of a plaque forming lambda specialized transducing phage is described . It consists of directed transposition of an F' plasmid into the gal region of a dnaAts galE- Escherichia coli strain by integrative suppression and deletion of the chlD region in order to shorten the distance between the marker of interest on the F' and the prophage serving to prepare an LFT1 lysate . An F' danC+thr+ plasmid was used here and lambdadthr and lambdaddnaC phages were isolated . In addition, lambdapdnaC was obtained from a double lysogen for lambdaddnaC and lambda b2.

Mol Gen Genet, 1977 Oct 20, 155(2), 131 - 8
Function of the tof gene product in modifying chemical stability of trp messenger RNA synthesized from the PL promoter of lambda trp phage; Yamamoto T et al.; The trp operon translocated into the early region of phage lambda can be transcribed under the control of two promoters, the authentic trp promoter (Ptrptrp mRNA) and the PL promoter of the N gene (PLtrp mRNA) (Imamoto and Tani, 1972; Ihara and Imamoto, 1976a) . PLtrp mRNA is stabilized with time after infection: at early times after infection chemical degradation of PLtrp mRNA is two-fold slower than for Ptrptrp mRNA, while at later times the stabilization of PLtrp mRNA is almost total . The stabilization of PLtrp mRNA is markedly reduced when the activity of the tof gene product is low due to a missense mutation of the tof gene . In contrast there is no significant reduction in stabilization when N function is lost by an amber mutation . On the basis of these and other experiments with lambdatrp susN7 tof12 phage, it is inferred that stabilization of the PLtrp mRNA is brought about by a modification of the "decay trigger", at least in part by the protein product of the tof gene.

Biochim Biophys Acta, 1977 Oct 18, 478(4), 337 - 91
Characterization of Allomyces genome; Ojha M et al.; Allomyces arbuscula DNA isolated from whole cells (bulk DNA) is composed of a major (alpha) and two minor components (beta & gamma) with buoyant densities in neutral CsCl corresponding to 1.721, 1.710 and 1.702 g/cm3, respectively . The DNA obtained from purified nuclei contains alpha component only . The beta component corresponds to mitochondrial DNA . The gamma component is also extra-nuclear but has not been characterized . The reassociation kinetics of sheared, bulk and nuclear DNA show that (i) 25 % bulk and 10% of nuclear DNA reanneal very rapidly and contain highly repeated sequences; (ii) moderately repeated sequences, accounting for 15% of both bulk and nuclear DNA, have a sequence complexity of approximately 7.2-10(6) daltons and are repeated about 320 times; (iii) the slow reannealing fraction accounts for about 60% of the genome and has kinetic properties similar to single copy sequences . The sequence complexity of this fraction was determined in relation to that of Escherichia coli . After a correction for the size of the repeated sequences the genome size of A . arbuscula was calculated to be 1.7-10(10) daltons.

Biochim Biophys Acta, 1977 Oct 18, 478(4), 407 - 16
Synthesis of complementary RNA on RNA templates using the DNA-dependent RNA polymerase of Escherichia coli; Bernard O et al.; It is shown that the DNA-dependent RNA polymerase of Escherichia coli can synthesize complementary RNA (cRNA) directly on rRNA and mRNA templates . Synthesis occurred preferentially in the presence of Mn2+ and at relatively high substrate and enzyme concentrations . No primer was required, and addition of oligo-U to a mRNA-dependent reaction gave no marked stimulation . Sedimentation analysis of cRNA made on different templates indicated that the products were mainly 2-4 S, but a fraction of the product was larger . Fingerprints of 32P-labelled cRNA made on 5 S rRNA and 18 S rRNA indicated that the complexity of the cRNAs was related to the size of the template, suggesting that a substantial portion of the templates were copied . This reaction provides a simple method for preparing cRNA of high specific activity for use in hybridisation studies, and possibly in sequence analysis . 32P-labelled cRNA made on 18 S and 28 S rRNA was a sensitive hybridisation probe for detection of the specific fragments of mouse DNA containing the rRNA genes.

Eur J Biochem, 1977 Oct 17, 80(1), 175 - 83
Analysis of calf-thymus satellite DNA: evidence for specific methylation of cytosine in C-G sequences; Gautier F et al.; Digestion of purified calf tymus satellite I (phi = 1.714 g/cm3) with a series of restriction enzymes shows that modification in this satellite occurs preferentially in the sequence C-G . This was also shown to be the case in the other satellites and in bulk chromosomal calf thymus DNA . Cloning of purified satellite I DNA in Escherichia coli makes sites, previously modified, available for cutting with certain restriction enzymes . All these 'new sites' contain the sequence C-G . High-resolution mass spectros-copy establishes that the satellites contain a low concentration of 5-methylcytosine . This infers that methylation which inhibits retriction enzyme cutting must occur preferentially in the sequence C-G . Hybridization of cRNA of cloned satellite I DNA with the satellites III (phi = 1.706 g/cm3) and IV (phi = 1.710 g/cm3) shows that there is no or little sequence homology between these satellites . Digestion of calf thymus satellite I DNA with endoR . EcoRI and subsequent hybridization studies with the fragments shows two EcoRI fragments in addition to the usual 1400-base-pair EcoRI repeat unit.

Eur J Biochem, 1977 Oct 17, 80(1), 35 - 41
Topography of Escherichia coli ribosomal protein L12 in situ; Hasnain S et al.; The ionization constants of each individual free amino group of Escherichia coli ribosomal protein L12 as it exists on the native intact 50-S subunit has been determined . All these amino groups are exposed and have pK values varying from 9.7 to 11.0 . The amino terminus, on the other hand, is unreactive and therefore appears to be buried . In addition, the reactivities indicate that the aminoterminal region of residues 1--59 undergoes a pH-dependent conformational change on the 50-S subunit.

Eur J Biochem, 1977 Oct 17, 80(1), 13 - 23
The palmityl binding sites of fatty acid synthetase from yeast; Schreckenbach T et al.; Fatty acid synthetase was covalently labelled with {14C}palmitic acid from {14C}palmityl-CoA . Tryptic and peptic digestion of the {14C}palmityl enzyme resulted in the formation of radioactive palmityl peptides carrying the long-chain acyl residue both in oxygen-ester and thio-ester linkage . The lipophilic palmityl peptides were purified by column and thin-layer chromatography using organic lolvent systems . Peptides arising from the acyl carrier protein, the condensing enzyme and the palmityl transferase were identified and characterized . The amino acid sequence of a 4'-phosphopant-etheine-containing peptide was established . It comprises 13 residues and shows a high degree of homology with the acyl carrier protein from Escherichia coli . A heptapeptide and an octapeptide from the palmityl transferase active site were partially sequenced . The identical amino acid composition of palmityl transferase and malonyl transferase core peptides is briefly discussed.

Biochim Biophys Acta, 1977 Oct 17, 470(2), 251 - 7
The dynamic structure of the Escherichia coli cell envelope as probed by 15N nuclear magnetic resonance spectroscopy; Irving CS et al.; Proton decoupled 15N NMR spectroscopy is shown to be a useful tool for probin the dynamic structure of the bacterial cell envelope . The proton decoupled 15N NMR spectra of Escherichia coli whole cells, cell envelopes and outer membranes were obtained and displayed resonances originating from protein side-chain groups, phosphatidylethanolamine, and peptidoglycan . Removal of phospholipids from the cell envelope resulted in a decrease in the motional freedom of peptidoglycan and cell envelope proteins . The mobility of the protein Arg side-chain groups is increased in the absence of peptidoglycan . These data provide insights into the effect of supramolecular organization on the dynamic structure of the E . coli cell envelope.

Eur J Biochem, 1977 Oct 17, 80(1), 255 - 60
Development of Escherichia coli virus T1: repression of host gene expression; Wagner EF et al.; Host protein synthesis, measured either as amino acid incorporation into proteins or as enzyme synthesis, is inhibited rapidly after infection Escherichia coli with T1 . Analysis of this inhibition, using a technique which distinguishes between translation and transcription, revealed that translation of host mRNA is specifically blocked . Comparison of the time course of T1-induced host repression with inhibition by the drugs rifampicin, nitrofurantoin and chloramphenicol showed that T1 affects the initiation step of host translation . Intact membranes are apparently essential for host repression, suggesting a membrane-mediated process . Concomitant viral protein synthesis is not required . The membrane-altering principle is a constituent of the viral particle.

Biochem J, 1977 Oct 15, 168(1), 15 - 22
2-Deoxy-D-galactose, a substrate for the galactose-transport system of Escherichia coli; Henderson PJ et al.; The following observations showed that 2-deoxy-D-galactose is a useful tool for the isolation and elucidation of the activity of one system for galactose uptake into Escherichia coli . 1 . 2-Deoxygalactose, which is not a substrate for growth of E . coli, was transported into strains of the organism induced for galactose transport . 2 . By using appropriate mutants it was shown that 2-deoxygalactose is a much better substrate for the galactose-transport system than for the methyl galactoside-transport system . This was confirmed by the results of mutual inhibition studies with substrates of each transport system . 3 . The glucose-, arabinose- or lactose-transport systems did not effect significant transport of 2-deoxygalactose . 4 . Like other substrates of the galactose-transport system, 2-deoxygalactose promoted effective proton uptake into de-energized suspensions of appropriate E . coli strains . 5 . The S183 series of E . coli mutants were found to contain a constitutive galactose-transport system, if 2-deoxygalactose transport is used as one criterion for such activity.

Biochim Biophys Acta, 1977 Oct 12, 462(1), 153 - 60
The anaerobic oxidation of dihydroorotate by Escherichia coli K-12; Andrews S et al.; The oxidation of dihydroorotate under anaerobic conditions has been examined using various mutant strains of Escherichia coli K-12 . This oxidation in cells grown anaerobically in a glucose minimal medium is linked via menaquinone to the fumarate reductase enzyme coded for by the frd gene and is independent of the cytochromes . The same dihydroorotate dehydrogenase protein functions in both the anaerobic and aerobic oxidation of dihydroorotate . Ferricyanide can act as an artificial electron acceptor for dihydroorotate dehydrogenase and the dihydroorotate-menaquinone-ferricyanide reductase activity can be solubilised by 2 M guanidine-HCl with little loss of activity.

Biochim Biophys Acta, 1977 Oct 12, 462(1), 113 - 20
Different effects of inhibitors on two mutants of Escherichia coli K12 affected in the Fo portion of the adenosine triphosphatase complex; Cox GB et al.; The effects of the inhibitors dicyclohexyl-carbodiimide (DCCD), bathophenanthroline and tertiary octylcatechol, on some enzyme activities in membranes from strains of Escherichia coli carrying mutations in the uncB or uncC genes have been studied . Membranes prepared from uncC mutants retain a normal DCCD-sensitive Mg2+-stimulated adenosine triphosphatase (Mg-ATPase) activity whereas in uncB mutants this enzyme activity is insensitive to DCCD . The membrane-bound Mg-ATPase activity from the uncC mutant strain, as compared with that from the normal strain, is only partially sensitive to the inhibitors bathophenanthroline or tertiary-octylcatechol . Both of these inhibitors stimulate the membrane-bound Mg-ATPase from uncB mutant strains . A DCCD-insensitive Mg-ATPase activity is found in the cytoplasmic fraction following cell disruption of either the uncB or the uncC mutants . The lipophilic chelators bathophenanthroline and tertiary-octylcatechol stimulate the activity of the 'soluble' Mg-ATPase in the uncB mutant but partially inhibit the activity in the uncC mutant . The NADH oxidase activities in membranes from both mutant and normal strains are strongly inhibited by tertiary-octylcatechol and bathophenanthroline but not by DCCD.

J Biol Chem, 1977 Oct 10, 252(19), 6889 - 94
DNA-directed in vitro synthesis of beta-galactosidase . Studies with purified factors; Kung HF et al.; The phage DNA-directed synthesis of beta-galactosidase has been examined in a system containing the following purified Escherichia coli factors: RNA polymerase; cyclic AMP receptor protein; N10-formyltetrahydrofolate Met-tRNAf transformylase; initiation factors 1, 2, and 3; elongation factors Tu, Ts, and G; release factors 1 and 2; 20 aminoacyl-tRNA synthetases; L factor (Kung, H . F., Spears, C., and Weissbach, H . (1974) J . Biol . Chem . 250, 1556-1562); and Lalpha (Kung, H.-F., Spears, C., and Weissbach, H . (1976) Fed . proc . 35, 1537) . Under these conditions, beta-galactosidase synthesis occurs at less than 1% of the rate obtained with unfractionated extracts, which suggested that other required components were lacking . The difficulty in obtaining large amounts of the purified aminoacyl-tRNA synthetases for these studies made it necessary to modify the system . It was possible to conserve many of the purified aminoacyl-tRNA synthetases since at least 13 of them could be replaced by an Ehrlich ascites extract . The ascites extract plus other E . coli purified factors was used as a basic system to search for additional components required for beta-galactosidase synthesis . The present report describes the purification from E . coli extracts of three fractions, called Lbeta, Lgamma, and Ldelta, that are needed to restore enzyme synthesis.

J Biol Chem, 1977 Oct 10, 252(19), 6885 - 8
Purification and characterization of polynucleotide phosphorylase from Escherichia coli . Probe for the analysis of 3' sequences of RNA; Soreq H et al.; A simple procedure for purifying polynucleotide phosphorylase from Escherichia coli cells by means of affinity chromatography on an RNA-Sepharose column is described . The purified enzyme preparation has a specific activity 3500-fold that of the crude extract and is essentially homogeneous, as determined by ultracentrifugation, polyacrylamide gel electrophoresis under denaturing conditions, isoelectric focusing and serological assays . It is virtually free of nuclease contamination, a property which permits its use in the synchronous phosphorolysis of RNA chains . The enzyme molecule is composed of three identical subunits of Mr = 84,000 . Each subunit contains three cysteine residues, one of which reacts with 5,5'-dithiobis(2-nitrobenzoic acid) whereas the two other groups are only exposed on denaturation of the protein . All three enzyme subunits participate in the processive phosphorolysis of the poly(A) tail of each globin mRNA chain . An advantageous method was developed for synchronous phosphorolysis of RNA molecules using a molar excess of polynucleotide phosphorylase immobilized onto Sepharose.

Biochemistry, 1977 Oct 4, 16(20), 4464 - 70
Incorporation of purine nucleoside 5'-{gamma-S}triphosphates as affinity probes for initiation of RNA synthesis in vitro; Reeve AE et al.; Synthetic DNA templates were transcribed by Escherichia coli RNA polymerase using nucleoside 5'-{gamma-S}triphosphates as one of the nucleotide substrates . Substitution of the thiol analogues for the normal nucleotides had no effect on the rate of RNA synthesis . RNA synthesized with either adenosine 5'-{gamma-S}triphosphate or guanosine 5'-{gamma-S}triphosphate was isolated with high efficiency on mercury-agarose columns prepared by activation with low concentrations of cyanogen bromide . Sulfur was shown to be incorporated at the 5' end of RNA by identification of the tetraphosphate HSpppA32p liberated after alkaline hydrolysis of HS(A-32pU)n (alternating copolymer synthesized by the action of E . coli RNA polymerase on d(A-T)n-d(A-T)n with adenosine 5'-{gamma-S}triphosphate and uridine 5'-{alpha-32P}triphosphate as substrates) . Transcripts elongated but not initiated with these thiol analogues did not bind to the affinity column . This technique provides an extremely sensitive assay for RNA synthesis initiation in vitro, since initiated transcripts containing radiolabel throught the entire transcript can be isolated.

Biochemistry, 1977 Oct 4, 16(20), 4368 - 71
Ribonucleotide reductase from Escherichia coli . Identification of allosteric effector sites by chromatography on immobilized effectors; von Dobeln U; Ribonucleotide reductase is responsible for the production of deoxyribonucleotides by catalyzing the reduction of ribonucleoside diphosphates . The enzyme is allosterically regulated in a complex way by the nucleoside triphosphates, ATP, dTTP, dGTP, dCTP, and dATP . Ribonucleotide reductase consists of two nonidentical subunits, proteins B1 and B2 . Both substrates and allosteric effectors bind exclusively to B1 . Binding of protein B1 to dTTP or dATP covalently coupled to Sepharose and elution with concentration gradients of the different nucleoside triphosphate effectors gave information about (1) the arrangement of the effector binding sites on protein B1 and (2) the affinity of the effectors for these sites . Protein B1 thus has two classes of effector binding sites . One class binds all effectors, as demonstrated by elution of the protein from dTTP-Sepharose with dATP, dGTP, ATP, or dCTP . The second class binds only dATP or ATP, since dATP and ATP were the only nucleotides which eluted protein B1 from dATP-Sepharose . These results confirm earlier data obtained by dialysis binding experiments . The eluting concentrations obtained for the different nucleoside triphosphates in experiments with dTTP-Sepharose could be used to calculate unknown dissociation constants for protein B1 -effector binary complexes . This was possible, since a plot of the eluting concentrations vs . known dissociation constants was linear.

Eur J Biochem, 1977 Oct 3, 79(2), 381 - 6
Construction, isolation and implications of repressor-galactosidase - beta-galactosidase hybrid molecules; Kania J et al.; Escherichia coli heterogenotes, which produce hybrid molecules between the chimaeric protein repressor-galactosidase and the enzyme beta-galactosidase, were constructed . Repressor-galactosidase in which fully active lac repressor is covalently linked to active beta-galactosidase, is an aggregate with a core structure of four beta-galactosidase parts and two peripheral lac repressor dimers . The lac repressor dimers, which are separated by tetrameric beta-galactosidase, retain all the biological activities of tetrameric lac repressor . Substitution of repressor-galactosidase subunits with beta-galactosidase subunits leads to hybrid molecules with y beta-galactosidase subunits aggregated with (4-y) repressor-galactosidase subunits (where y = 1, 2 or 3) . A 2:2 hybrid, i.e . a tetrameric beta-galactosidase core with one lac repressor dimer grafted to it, binds at least 100 times less strongly to 32P-labelled lambdaplac DNA than pure lac repressor or repressor-galactosidase . The data suggest a model in which lac repressor binds with two subunits to lac operator and with the other two subunits elsewhere on the DNA, possibly on sequences like the lac operator.

C R Acad Sci Hebd Seances Acad Sci D, 1977 Oct 3, 285(7), 825 - 8
{Inhibition of biological methylations by t,t-farnesylacetone, a constituant of the androgenic gland of the male crab, Carcinus maenas}; Tekitek A et al.; t, t-farnesylacetone 1 and hexahydrofarnesylacetone 2 have been previously identified in extracts from the androgenic gland of the male Crab Carcinus maenas . These compounds inhibit in vitro the methylation of E . coli B tRNA and of Calf thymus histones with S-adenosylmethionine methyl-14C as methyl donor and methylases from Crab testis . Rat liver or a 1-adenine methylase from a Mouse plasmocytoma (1 is approximately 200 times more active than 2).

Eur J Biochem, 1977 Oct 3, 79(2), 519 - 23
The effect of modification of cytosines in Escherichia coli 16-S rRNA on reconstitution and function of 30-S ribosomes; Wrede A et al.; O-Methylhydroxylamine (methoxyamine) was used for selective modification of cytosine residues in Escherichia coli 16-S rRNA . It was shown that cytosines accessible for methoxyamination are randomly distributed along the 16-S rRNA chain . Preparations of methoxyaminated 16-S rRNA, containing 2--130 modified cytosines/chain, still retained the ability to bind 30-S proteins, but the physical assembly of reconstituted particles was incorrect . The protein compositions of the reconstituted and native particles did not differ qualitatively from each other . However, the amount of protein in reconstituted particles decreased with an increasing number of methoxyaminated cytosines in 16-S rRNA . The particles obtained sedimented slower than native 30-S subunits, lost their ability to associate with 50-S ribosomes and to bind native phage f2 RNA . In contrast, modification of 16-S rRNA did not affect binding of poly(U) by reconstituted particles.

Eur J Biochem, 1977 Oct 3, 79(2), 495 - 504
On the distribution and packing of RNA and protein ribosomes; Serdyuk IN et al.; From the analysis of the measured radii of gyration of the RNA (Rg = 6.6 +/- 0.3 nm) and protein (Rg = 10.2 +/- 0.5 nm) components of the 50-S subparticle of Escherichia coli ribosomes it is concluded that proteins containing a large amount of hydrodynamically bound water are located on the periphery of the tightly packed RNA . We found that the common features of the measured X-ray scattering curves of the E . coli 70-S ribosome, its 30-S and 50-S subparticles and wheat 80-S ribosomes in the region of scattering angles corresponding to scattering vectors mu from 1 to 5 nm-1 reflect features of the RNA compact packing . A hypothesis is proposed that the compact packing of RNA helices in the range of Bragg distances of 4.5--2.0 nm is a general structural feature of all ribosomal particles.

Eur J Biochem, 1977 Oct 3, 79(2), 433 - 41
Interrelation between transfer RNA and amino-acid-activating sites of methionyl transfer RNA synthetase from Escherichia coli; Jacques Y et al.; Binding of tRNA(Met/f) to the monomeric trypsin-modified methionyl-tRNA synthetase turns off the methionine-dependent isotopic ATP--PPi exchange . In the case of the dimeric native methionyltRNA synthetase, one anticooperatively bound tRNA(Met/f) inhibits the exchange by only 50% . These behaviours of tRNA do not require the integrity of the 3'-terminal adenosine . Esterification by methionine of the 3' end of tRNA reinforces the affinity of tRNA(Met/f)for the enzymes . In the case of the native enzyme, due to this effect, a second binding mode for methionyl-tRNA may be demonstrated through the isotopic exchange . This additional binding of tRNA corresponds to the expression of the anticooperatively blocked tRNA binding site . Methionine reverses competitively the reinforcing effect of the esterified methionyl moiety on tRNA binding . It is concluded that after esterification of tRNA, the aminoacyl residue still binds the enzyme, probably within the methionine activating site . The latter behaviour may account for the observation that excess methionine accelerates the aminoacylation turnover rate of tRNA(Met/f).

Eur J Biochem, 1977 Oct 3, 79(2), 401 - 9
Studies on the transcription complex of Escherichia coli RNA polymerase; Rohrer H et al.; To study the chain elongation phase of enzymatic RNA synthesis ternary transcription complexes with T7 DNA or poly{dA) - (dT)} as template were isolated by gel exclusion chromatography . The DNA in these complexes contains single-stranded regions which are recognized by a single-strand-specific nuclease from Neurospora crassa . The non-codogenic DNA strand in the poly{(dA) - (dT)} ternary complex is preferentially hydrolysed by the nuclease . The polymerase protects predominantly the codogenic strand in this complex from digestion by DNAse I . In the T7 DNA ternary complex a DNA fragment with a chain length of approximately 26 nucleotides and an RNA fragment of about 22 nucleotides are protected by polymerase from digestion by DNAse and RNAse.

Eur J Biochem, 1977 Oct 3, 79(2), 395 - 9
Circular dichroism studies of the binding of o-nitrophenyl-beta-D-fucoside and o-nitrophenyl-beta-D-galactoside to lac repressor; Maurizot JC et al.; The binding of o-nitrophenyl-beta-D-fucoside and o-nitrophenyl-beta-D-galactoside to Escherichia coli lac repressor was investigated by circular dichroism in the wavelength range 300--400 nm corresponding to the o-nitrophenyl chromophores . The CD signal of both ligands drastically changed when they bound to lac repressor due to the asymmetric interaction of the o-nitrophenyl ring with chemical groups of protein . The CD spectra of bound ligands indicate close similarity between the environment of o-nitrophenyl-beta-D-fucoside and o-nitrophenyl-beta-D-galactoside on lac repressor . The CD signal is used to calculate the binding parameters (K and n) to lac repressor . It is demonstrated that the limited proteolytic digestion of lac repressor which gives a 'core protein' does not affect the environment of both ligands on the protein.

Biochim Biophys Acta, 1977 Oct 3, 470(1), 70 - 83
The preparation and use of pyridoxal {32P}phosphate as a labeling reagent for proteins on the outer surface of membranes; Eger R et al.; Pyridoxal {32P} phosphate was prepared using {gamma-32P} ATP, pyridoxal, and pyridoxine kinase purified from Escherichia coli B . The pyridoxal {32P} phosphate obtained had a specific activity of at least 1 Ci/mmol . This reagent was used to label intact influenza virus, red blood cells, and both normal and transformed chick embryo fibroblasts . The cell or virus to be labeled was incubated with pyridoxal {32P} phosphate . The Schiff base formed between pyridoxal {32P} phosphate and protein amino groups was reduced with NaBH4 . The distribution of pyridoxal {32P} phosphate in cell membrane or virus envelope proteins was visualized by autoradiography of the proteins separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis . The labeling of the proteins of both influenza and chick cells appeared to be limited exclusively to those on the external surface of the virus or plasma membrane . With intact red blood cells the major portion of the probe was bound by external proteins, but a small amount of label was found associated with the internal proteins spectrin and hemoglobin.

Agents Actions, 1977 Oct, 7(4), 465 - 8
The effect of bovine serum albumin on the in vitro inhibition of chemotaxis by anti-inflammatory agents; Rivkin I; The anti-inflammatory agents, phenylbutazone, naproxen and niflumic acid inhibited in vitro rabbit peritoneal neutrophil chemotactic responsiveness to Escherichia coli derived chemotactic factor/s when added to cells suspended in 0.1% bovine serum albumin (BSA) . Inhibition of chemotaxis by these drugs was markedly diminished as the BSA concentration was increased to 2% . Experiments with phenylbutazone demonstrated that inhibition of chemotaxis could be observed using neutrophils suspended in 2% BSA by either increasing the drug concentration or by preincubating the cells suspended in 0.1% with the drug prior to the addition of the additional BSA . These data suggest that protein binding can prevent in vitro inhibition of neutrophil chemotaxis by anti-inflammatory agents.

J Toxicol Environ Health, 1977 Oct, 3(3), 535 - 43
Immune response in aged mice exposed to lead; Koller LD et al.; Mice were exposed to 0, 13, or 1,300 ppm lead in drinking water for 18 months . The immunological assays examined were mitogen (lipopolysaccharide E . coli, concanavalin A, and phytohemagglutinin-P) stimulation of lymphocytes; erythrocyte-antibody (EA), erythrocyte-antibody-complement (EAC), and phagocytosis of macrophages; and EAC of splenic lymphocytes . As measured by the majority of these assays, the low dosage (13 ppm) of lead tended to stimulate certain immune responses (lymphocyte mitosis, EA, and EAC) while the high dosage (1,300 pm) did not provoke an appreciable alteration . The results were interpreted by comparing data on aged mice with data on young adult mice . It was apparent from this comparison that the aged mice were naturally immunosuppressed . Therefore, the results obtained from lead-exposed mice were unpredictable.

J Natl Cancer Inst, 1977 Oct, 59(4), 1311 - 4
Superiority of adriamycin-14-octanoate over adriamycin in reducing viability of methotrexate-resistant L5178Y cells: brief communication; Hill BT et al.; Adriamycin-14-octanoate (ADR-OCT) was superior to adriamycin (ADR) in reducing the viability of L5178Y cells resistant to methotrexate (MTX) . This effect was seen in logarithmically growing and plateau-phase cultures and increased both with dose and duration of exposure . Both ADR-OCT and ADR were effective inhibitors of the exogenous Escherichia coli DNA-dependent RNA polymerases in vitro and of the endogenous polymerase in mammalian cultured cells . Drug concentrations required for approximately 50% enzyme inhibition in both systems were comparable for both agents, being of the order of 10(-5) M . These experimental studies suggested that ADR-OCT may be a valuable agent for treating neoplasms resistant to MTX.

J Cell Physiol, 1977 Oct, 93(1), 137 - 46
Repetitive DNA in differentiating chick tissues; Ayres KN; Embryonic chick DNA from different tissues was examined for differences in relative content of highly repetitive DNA which might indicate specific DNA amplification in somatic cells . The content of repetitive sequences in DNA isolated from cerebrum, muscle, and neural retina tissues, at the same and at different embryonic stages, was determined by hydroxyapatite fractionation of partially reassociated DNA samples . An unrenatured marker DNA (C14-labeled E . coli DNA) was added to each chick DNA sample in order to monitor the nonspecific single-stranded DNA retention by each hydroxyapatite column . When chick DNA samples were sheared to a double-stranded length of 1,300 nucleotide pairs, an average of 20.2% +/- 2.2% of the DNA was found to reassociate at a Cot value of 10 . The quantity of the fast reassociating sequences was found to constitute the same fraction of the DNA in all the tissues studied . In addition, all the reassociated DNA samples exhibited the same CsCl density classes . The studies also indicated that most chick DNA repetitive sequences are interspersed with nonrepetitive sequences.

J Bacteriol, 1977 Oct, 132(1), 67 - 72
Regulation of argA operon expression in Escherichia coli K-12: cell-free synthesis of beta-galactosidase under argA control; Kelker N et al.; Regulation of argA operon expression in Escherichia coli K-12 was studied in a cell-free, deoxyribonucleic acid-dependent, enzyme-synthesizing system . lambdaAZ-7 deoxyribonucleic acid, which carries a fusion of the lacZ structural gene to the argA operon so that beta-galactosidase synthesis is under argA regulation, was used as the template . To eliminate extraneous readthrough from lambda promoters, lambda repressor was introduced into the synthesis mixtures by preparing the S-30 component from a strain (514X5a-12-29) that carries a multicopy hybrid plasmid (pKB252) containing the lambdacI gene . Under these conditions beta-galactosidase synthesis was repressed 90% by the arginine repressor when a sufficient concentration of L-arginine was present . This repression could be overcome by escape synthesis when the lambdaAZ-7 deoxyribonucleic acid concentration in the synthesis mixtures was increased . Guanosine 3'-diphosphate-5'-diphosphate stimulated beta-galactosidase synthesis from this template.

J Bacteriol, 1977 Oct, 132(1), 314 - 20
Metal ion dependence of a heat-modifiable protein from the outer membrane of Escherichia coli upon sodium dodecyl sulfate-gel electrophoresis; McMichael JC et al.; One heat-modifiable protein of Escherichia coli outer membrane does not completely change to the high-temperature form in the presence of magnesium ion in sodium dodecyl sulfate solution . When the metal ion complexing reagents ethylenediaminetetraacetic acid, phosphate ion, hydroxyl ion, or the competitive cations Zn2+ or Ca2+ are added to the sodium dodecyl sulfate-solubilized sample of outer membrane, and then the sample is heated to 100 degrees C and recooled to room temperature, the protein is almost completely converted to the high-temperature form . In control samples, or if sodium chloride, magnesium chloride, or manganous chloride are added to these samples and treated the same way, a large amount of the low-temperature form of the protein is preserved . beta-Mercaptoethanol additions gave the same results as the metal ion complexing reagents and may owe its activity in these solutions to metal-binding activity and not to its role as a reducing reagent . We concluded that magnesium ion may be involved with stabilization of the low-temperature form of the protein either by directly binding the magnesium or by mediating interaction with other components of the membrane.

J Immunol, 1977 Oct, 119(4), 1406 - 12
Analysis of the diversity of murine antibodies to dextran B1355 . II . Demonstration of multiple idiotypes with variable expression in several strains; Hansburg D et al.; We have developed radioimmunoassays that detect idiotypic (variable region) differences among the alpha(1 leads to 3) dextran-binding meyloma proteins U102, J558, and M104 as well as an assay that detects variable region determinants common to all three proteins . Using these assays, we have examined 7S and 19S anti-alpha(1 leads to 3) dextran antibodies induced in five murine strains of the a1 IgCH linkage group and the recombinant strain BAB/14 . All idiotypes were expressed in both 19S and 7S antibodies from all strains, but with considerable strain-specific variability in penetrance . In two strains, one additional type of antibody, which lacked all four idiotypic determinants, generally constituted the bulk of total anti-alpha(1 leads to 3) dextran antibodies.

Zentralbl Bakteriol {Orig B}, 1977 Oct, 165(2), 242 - 9
{Comparison of efficacy of 14 procedures for the hygienic disinfection of hands (author's transl)}; Wewalka G et al.; The efficacy of 14 procedures for the hygienic disinfection of hands mostly with commerical preparations was tested by a new experimental model developed at the Institute of Hygiene of the university Vienna (1,3) . The disinfectant power was clearly dependent on the duration of treatment as well as on the kind of alcohol used in the preparation (n-Propanol better than iso-Propanol better than Ethanol) . After one minute the efficacy of all preparations containing one of the three alcohols as active agent was well comparable to that of the standard procedure which according to our proposal (5) uses iso-Propanol 60% (ml/ml) for 1 minute . For preparations with n-Propanol as the main active agent (Satinazid and Sterillium) this was true even after treatment for a period as short as 0.5 min . In our opinion disinfecting detergents are out of place for hygienic disinfection of hands . One preparation representing this group (Versuchspraparat A) was far less effective than the standard procedure.

J Dairy Res, 1977 Oct, 44(3), 433 - 40
Mammary blood flow during experimental Escherichia coli endotoxin induced mastitis in goats and cows; Dhondt G et al.; The effect of intramammary infusion of Escherichia coli endotoxin upon mammary blood flow was studied in lactating goats and cows . Blood flow was recorded by means of an electromagnetic flow probe chronically implanted around one mammary artery . Endotoxin mastatis was always accompanied by a significant increase in mammary blood flow, characterized by 2 conspicuous peaks . The flow returned to control values by the thirteenth hour after infusion . Other symptoms of acute mastitis were: fever, increased heart rate, swelling, heat and pain of the gland, increased chloride and total cell count in milk.

Biomedicine, 1977 Oct, 27(7), 258 - 60
Obtaining hyperimmune anti-coli (anti-Escherichia) human plasma; Skurkovich SV et al.; Anticoli (anti-Escherichia) plasma has been obtained from donors immunized with viable Escherichia oral vaccines, prepared from Str-d mutants of E . coli . Anticoli plasma has an therapeutic effect against diseases of Escherichia etiology.

Br J Exp Pathol, 1977 Oct, 58(5), 549 - 56
Delayed hypersensitivity to Escherichia coli in the rat--a study of its possible relevance to the pathogenesis of kidney scars; Asscher AW et al.; Rats sensitized to various strains of Escherichia coli (078, O2K13H1, O6K13H1 and O6K2a2cH1) showed cutaneous delayed type hypersensitivity (DTH) reactions after intradermal challenge with the same or a different strain of Esch . coli . Cutaneous DTH was transferred to non-sensitized rats by administration of lymphocytes from sensitized animals . The common antigen(s) responsible for DTH was not identified but DTH reactions were found to be unrelated to the O or K serotype of the Esch . coli strains used . Intrarenal administration of killed Esch . coli to animals showing cutaneous DTH and non-sensitized controls did not produce evidence of DTH reactions of the kidney . Instead it was shown that intrarenal administration of formalin- or heat-killed Esch . coli leads to kidney scarring in both sensitized animals and non-sensitized controls . These scars were comparable in severity, and were similar to those obtained after infection of the kidney with live organisms . It is concluded that DTH reactions do not play a role in the pathogenesis of kidney scarring associated with Esch . coli infection of the rat kidney but that the strains of Esch . coli studied possess a common heat- and formalin-stable nephrotoxic factor which induces kidney scarring.

Proc Natl Acad Sci U S A, 1977 Oct, 74(10), 4337 - 40
Limited accessibility of chromatin satellite DNA to RNA polymerase from Escherichia coli; Gjerset RA et al.; An attempt was made to elucidate some of the factors influencing the fidelity with which isolated chromatin from mouse L-cells is transcribed by RNA polymerase from Escherichia coli by analyzing the in vitro transcript for the presence of satellite sequences . These sequences are absent from cellular RNA and therefore reflect aberrant transcription . The results indicate that satellite sequences are underrepresented in chromatin transcripts relative to those of DNA . This selectivity is insensitive to many variables in procedures for the isolation and transcription of chromatin . However, lowering the ratio of enzyme to template further reduced the proportion of satellite sequences in the transcript . We conclude that a primary factor influencing the extent of aberrant transcription is the level of enzyme used . Under limiting enzyme conditions, an efficient selection against satellite sequences is observed . However, under conditions of enzyme excess, the enzyme initiates chains at weaker secondary promoters localized in regions of the chromatin containing satellite DNA.

Nucleic Acids Res, 1977 Oct, 4(10), 3627 - 42
Complex formation between ribosomal protein S1, oligo-and polynucleotides: chain length dependence and base specificity; Lipecky R et al.; In order to examine the nature of the complex formation between the ribosomal protein S1 and nucleic acids three methods were used: Inhibition of the reaction of n-ethyl{2.3 14C}-maleimide with S1 by the addition of oligonucleotides; adsorption of the complexes to nitrocellulose filters; and equilibrium dialysis . The complex formation is Mg2+ dependent at low salt concentrations and becomes Mg2+ independent at an ionic strength greater than 90 mM . Oligouridylates of increasing chain length reach an optimal KA of 3-3-10(7) M-1 at a chain length of n=13-14 . Protein S1 contains one binding site for long chain oligouridylates, such as U12, and the standard-free-energy change on binding caused by one Pu increment is 0.41 kcal/mol, when n varies between five and fourteen . Complex formation is insensitive to the capacity of the homopolynucleotide bases to form hydrogen bonds . Homopolynuceotides, however, showing a Tm less than 250 in the buffer system used show an increased affinity for S1 compared to poly(A) and poly(C) (Tm greater than 40 degrees) . The data are discussed with respect to the proposed binding of protein S1 to the 3-terminal end of the 16S RNA.

Nucleic Acids Res, 1977 Oct, 4(10), 3415 - 39
Sequence specific interaction of the chromosomal proteins with DNA; Tuan D et al.; Calf thymus chromatin was partially deproteinized by 0.6-1 M NaCl extraction . From the shape of the temperature derivative plot of its melting curve, the DNA in each chromatin was resolved into regions of exposed DNA, and DNA still complexed with proteins . The partially deproteinized chromatin was capable of directing in vitro RNA synthesis in an amount proportional to the fraction of exposed DNA . The in vitro RNA transcript was hybridized to denatured calf DNA under hybridization conditions where only RNA's transcribed from repetitive DNA sequences were able to form hybrids . From the results it is deduced that the in vitro RNA transcripts of 0.6 M NaC1-extracted chromatin after the removal of HI histones plus one-quater of the non histones may be transcribed from repetitive DNA sequences and those of 1 M NaCl-extracted chromatin contain more transcripts from the unique DNA sequences.

Nucleic Acids Res, 1977 Oct, 4(10), 3327 - 40
Ribosomal protein-nucleic acid interactions . I . Isolation of a polypeptide fragment from 30S protein S8 which binds to 16S rRNA; Bruce J et al.; Within the bacterial ribosome a large number of specific protein and rRNA interactions appear to be required for assembly of the particle and its subsequent function in protein synthesis . In this communication it is shown that it is possible to isolate cyanogen bromide digestion products from ribosomal 30S protein S8 which will interact stoichiometrically with 16S rRNA . In addition to this a small binding polypeptide was generated from S8-16S rRNA complexes which were treated with proteinase K . The digestion of the complex yields a "protected" fragment of protein S8 which binds to 16S-rRNA . The isolated fragment will reassociate with 16S rRNA . It is not displaced by other 30S ribosomal proteins and blocks the binding of intact S8 to 16S rRNA . The size the possible structure of the S8 protein binding site are discussed and compared with the binding of cyanogen bromide digestion products which bind to 16S rRNA.

J Biochem (Tokyo), 1977 Oct, 82(4), 1045 - 53
Purification and characterization of active component and active fragment of colicin E3; Ohno S et al.; 1 . Two components of colicin E3, namely proteins A and B, were prepared by means of an improved method . 2 . Protein A thus obtained was more than a thousand times as active as native colicin E3 when they were assayed in terms of activity for ribosome inactivation . 3 . Protein A was reconstituted to colicin E3 simply by mixing with protein B . 4 . Trypsin digestion of colicin E3 yielded two fragments, T1 and T2, probably by cleaving one specific bond of the A moiety of colicin E3 . 5 . T2 was a complex of T2A and B proteins . T2A showed an activity equivalent to that of protein A when assayed in the in vitro system, and its activity was neutralized by protein B . Thus T2A was assigned as an active fragment of protein A . 6 . T2A has a characteristic amino acid composition rich in the basic amino acid, lysine . 7 . The structure and function of the colicin E3 molecule is discussed based on the results obtained with its components as well as with fragments of the components.

Appl Environ Microbiol, 1977 Oct, 34(4), 382 - 5
Filtration removal of endotoxin (pyrogens) in solution in different states of aggregation; Sweadner KJ et al.; Bacterial lipopolysaccharides are recognized as the major cause of pyrogenic reactions from parenteral solutions . Molecular filtration was used to remove these pyrogenic molecules (endotoxins) from contaminated parenteral solutions . Because bacterial lipopolysaccharides can exist in different states of aggregation, depending on the composition of the solution they are suspended in, the full range of possible states of aggregation was examined by using filters with a wide range of pore sizes . Filters of different pore sizes retained endotoxin lipopolysaccharide presumed to be in the vesicle form, the micelle form, or the detergent-solubilized form in aqueous solutions . Endotoxins (pyrogens) were successfully removed from artificially contaminated solutions of concentrated antibiotics by using filters of 10,000-nominal-molecular-weight limit.

Mutat Res, 1977 Oct, 45(1), 137 - 45
Evidence for inactivation of DNA repair in frozen and thawed mammalian cells; Slor H et al.; A variety of cell strains and lines were frozen and thawed by conventional techniques for cell storage . Following thawing, extracts of cells were prepared and incubated with UV-irradiated E . coli DNA . Thymine dimer excision activity present in extracts of unfrozen cells was lost in extracts of recently thawed cells . The ability to exercise dimers was restored after about 40 h post-thawing, but the recovery was inhibited if cells were cultured in the presence of puromycin . Correlating with the loss of dimer excising activity there was a reduced cell viability as measured by trypan blue dye exclusion.

J Bacteriol, 1977 Oct, 132(1), 90 - 9
Replication of thermosensitive Rts1 plasmid deoxyribonucleic acid at the nonpermissive temperature; Yamamoto T et al.; Replication of the thermosensitive drug resistance factor Rts1 was studied at the nonpermissive temperature (42 degrees C) . It was concluded from the following observations that replication of this plasmid takes place at 42 degrees C without involving the covalently closed circular (CCC) form of deoxyribonucleic acid (DNA) . (i) DNA-DNA- reassociation kinetics studies with purified Rts1 DNA showed that Rts1 DNA increased several-fold during cell growth at 42 degrees C while very little, if any, CCC DNA was synthesized . (ii) When Escherichia coli 20S0(Rts1) was labeled with {3H}thymidine at 42 degrees C, a significant amount of radioactive DNA hybridizable to Rts1 DNA was formed . This DNA was found in a fraction where DNA other than CCC DNA was expected in alkaline sucrose density gradient centrifugation analysis . When E . coli 20S0(Rts1) was labeled at 32 degrees C, the labeled CCC DNA did not disappear during a chase period at 42 degrees C . This indicates that preformed CCC DNA does not participate in replication at the nonpermissive temperature . These results are consistent with the hypothesis that there are two modes of replication of Rts1 DNA, one involving a CCC molecule and the other not involving this form, and that only the latter mode takes place at the nonpermissive temperature.

J Bacteriol, 1977 Oct, 132(1), 352 - 5
Effect of the relA gene on derepression of amino acid biosynthetic enzymes in growing Escherichia coli depends on the pathway being derepressed; Furano AV et al.; Derepression of an enzyme in the arginine biosynthetic pathway, but not of an enzyme in the tryptophan biosynthetic pathway, is inhibited during the stringent response produced by a partial deprivation of valyl transfer ribonucleic acid in a rel+ strain . In contrast, derepression of the tryptophan biosynthetic enzyme, but not of the arginine biosynthetic enzyme, was inhibited during the relaxed response produced in an isogenic relA strain by the partial deprivation of valyl transfer ribonucleic acid.

J Bacteriol, 1977 Oct, 132(1), 349 - 51
Transformation in Escherichia coli: cryogenic preservation of competent cells; Morrison DA; Escherichia coli cells prepared for transformation by treatment with cold 0.1 M CaCl2 remained viable and competent after storage at -82 degrees C in 15% glycerol; thawed-cell samples yielded up to 10(6) transformants per microgram of plasmid deoxyribonucleic acid.

J Bacteriol, 1977 Oct, 132(1), 332 - 40
Studies of colicin E1 plasmid functions by analysis of deletions and TnA insertions of the plasmid; Inselburg J; The further identification of regions of the colicin E1 plasmid that affect plasmid functions has been achieved by studying deletions and TnA insertions of the plasmid . Colicin production, colicin immunity, relaxation of plasmid deoxyribonucleic acid, and plasmid incompatibility functions have been examined . A strong correlation has been observed between the ability of colicin E1 plasmid deoxyribonucleic acid to be relaxed and the ability of that plasmid to be transferred by conjugation.

J Bacteriol, 1977 Oct, 132(1), 321 - 31
Isolation and genetic analysis of deletion mutants of colicin E1 plasmids carrying a TnA insertion; Inselburg J et al.; Deletions of colicin E1 (colE1) plasmid deoxyribonucleic acid (DNA) carrying the TnA transposon have been isolated . All except two were generated by nuclease digestion of plasmid DNA from its EcoRI-sensitive site . A plasmid containing about 16% of the ColE1 DNA (6.5 X 10(5) daltons) was generated that also contained the part of the TnA transposon conferring ampicillin resistance . The extents of different deletions were determined by analysis of restriction endonuclease fragments generated by the restriction endonucleases HaeII, BamHI, and HincII.

J Bacteriol, 1977 Oct, 132(1), 308 - 13
Amino acid replacement in a mutant lipoprotein of the Escherichia coli outer membrane; Inouye S et al.; The primary structure of a mutant lipoprotein of the outer membrane of Escherichia coli was investigated . This mutant was previously described as a mutant that forms a dimer of the lipoprotein by an S-S bridge (H . Suzuki et al., J . Bacteriol . 127:1494-1501, 1976) . The amino acid analysis of the mutant lipoprotein revealed that the mutant lipoprotein had an extra cysteine residue, with concomitant loss of an arginine residue . From the analysis of the mutant lipoprotein revealed that the mutant lipoprotein had an extra cysteine residue, with concomitant loss of an arginine residue . From the analysis of tryptic peptides, it was found that the arginine residue at position 57 was replaced with a cysteine residue . The amino terminal structure of the mutant lipoprotein was found to be glycerylcysteine, as in the case of the wild-type lipoprotein . The present results show that the mutation that was previously determined to map at 36.5 min on the E . coli chromosome occurred in the structure gene (lpp) for the lipoprotein . This was further confirmed by the fact that a merodiploid carrying both lpp+ and lpp produces not only the wild-type lipoprotein but also the mutant lipoprotein.

J Bacteriol, 1977 Oct, 132(1), 294 - 301
Envelope-associated nucleoid from Caulobacter crescentus stalked and swarmer cells; Evinger M et al.; Envelope-associated nucleoids have been isolated from Caulobacter crescentus by using a modification of the procedure of T . Kornberg et al . (Proc . Natl . Acad . Sci . U.S.A . 71:3189-3193, 1974) . The development of a Ludox density gradient procedure has permitted preparation of large quantities of synchronous cells . The sedimentation coefficients of the envelope-associated nucleoids of stalked and swarmer cells, prepared under conditions of equivalent cell lysis, were 3,000S and greater than 6,000S respectively . Small differences in the relative amounts of deoxyribonucleic acid, ribonucleic acid, and protein in stalked and swarmer cell envelope-associated nucleoids could not account for the large differences in sedimentation behavior . These characteristic sedimentation coefficients were retained in mixing experiments.

J Bacteriol, 1977 Oct, 132(1), 23 - 7
Genetic locus (ompB) affecting a major outer-membrane protein in Escherichia coli K-12; Sarma V et al.; Three multiply colicin-tolerant mutants in Escherichia coli K-12 from the TolIV, TolXIV, and TolXV phenotypic groups, all lacking or having only trace amounts of protein 1, a major outer-membrane protein, were mapped by Hfr crosses, and the position on the chromosome was confirmed by cotransduction with nearby markers . The mutations were located near malQP in the 74-min region of the E . coli chromosome . This locus is designated ompB, and analysis of data from two three-point crosses determined the linear sequence of genes to be aroB-ompB-malQP-glpD.

J Bacteriol, 1977 Oct, 132(1), 174 - 9
Role of methionine in the synthesis of nucleoside Q in Escherichia coli transfer ribonucleic acid; Katze JR et al.; Previously, we reported that starvation of Rel Escherichia coli for methionine, but not leucine or histidine, results in chromatographically unique species of aspartyl-specific transfer ribonucleic acid (tRNAAsp) lacking the modified nucleoside Q . The present studies demonstrate that methionine starvation of Rel+ E . coli yields a qualitatively similar, but less pronounced, effect . Furthermore, during recovery from methionine starvation in Rel E . coli, the chromatographic elution pattern of tRNAAsp shifts towards that observed for unstarved cells after 1 h of recovery, and the shift appears complete after 2 h of recovery . This shift is inhibited by rifampin . Incorporation of {2-14C}methionine or {methyl-3H}methionine into growing cells of E . coli does not result in labeling of nucleoside Q . We interpret these findings to indicate that methionine has an indirect role in Q formation and that Q-deficient tRNA can be modified slowly to contain Q but that transcription is required . The chromatographic elution patterns of tRNAAsp from Rel E . coli starved for arginine, lysine, or glutamic acid indicate that these amino acids are not the source of the three- or five-carbon sequences in the modified portion of Q.

J Bacteriol, 1977 Oct, 132(1), 127 - 31
Identification of a temperature-sensitive asparaginyl-transfer ribonucleic acid synthetase mutant of Escherichia coli; Yamamoto M et al.; A temperature-sensitive mutant of Escherichia coli K-12 isolated previously (H . Ohsawa and B . Maruo, J . Bacteriol . 127:1157-1166, 1976) was found to have an alteration in asparaginyl-transfer ribonucleic acid synthetase . This alteration can account for the temperature-sensitive phenotype of the mutant . No evidence was obtained to support the previous suggestion that ribosomal protein S1 is altered in this mutant . Combined with the previous genetic studies, we conclude that the newly defined genetic locus, asnS, for the asparaginyl-transfer ribonucleic acid synthetase maps near pyrD at 21 min on the E . coli chromosome.

Can J Biochem, 1977 Oct, 55(10), 1082 - 90
Proteolytic digestion and labelling studies of the organization of the proteins in the outer membrane of Escherichia coli; Reithmeier RA et al.; The arrangement of the proteins in the outer membrane of Escherichia coli was examined by treating intact cells and isolated membrane preparations with fluorescamine and with pronase . Intact wild-type cells, or those of a mutant in which the core region of the lipopolysaccharide was absent, were equally resistant to pronase treatment . The protein components of isolated outer membrane preparations varied in their rate of digestion and labelling with fluorescamine . The N-terminal portion of protein B was removed by pronase to yield a fragment (protein Bp) still embedded in the membrane . Protein Bp was not significantly enriched in nonpolar amino acids, suggesting that protein B may not be held in the membrane primarily by hydrophobic interactions . This was confirmed by reconstitution experiments in which protein B could be reassociated with itself, without lipopolysaccharide or phospholipid, in the presence of divalent cation such that pronase digestion of the reassociated material gave protein Bp.

J Med Chem, 1977 Oct, 20(10), 1351 - 4
Synthesis of 5,6-dihydro-8(7H)-quinolinone thiosemicarbazones as potential antitumor agents; Lemke TL et al.; 5,6-Dihydro-8(7H)-quinolinone was synthesized and converted into thiosemicarbazones which could be considered to be semirigid analogues of the 2-formylpyridine thiosemicarbazone class of antitumor agents . The Z and E isomers were separated and identified by 1H NMR and UV . Although the compounds showed essentially no inhibitory activity against the enzyme alkaline phosphatase, several of these agents had demonstrable anticancer activity in mice bearing the P388 leukemia . The E-configuration analogues in general were slightly more active than their corresponding Z isomers.

J Med Chem, 1977 Oct, 20(10), 1283 - 7
Polynucleotide analogues . Copolymers of vinyl bases with acrylic acid, methylacrylic acid, acrylamide, and 1-vinylpyrrolidone; Maggiora L et al.; Preliminary studies are reported on the synthesis and testing of substituted vinyl polymers that are designed to have sequence specific affinity for polyribonucleic acids . Copolymers of 1-vinyluracil with acrylic acid, 2-methylacrylic acid, or 1-vinyl-2-pyrrolidone were prepared by gamma-irradiation to give the respective polymers 1,3, and 4 . Similarly, 9-vinyladenine yielded copolymeric products 5 and 6 with acrylic acid or 2-methylacrylic acid . Radical initiated polymerization of 9-vinyladenine with acrylamide yielded copolymer 7 . The products were characterized by elemental analysis and ultraviolet, infrared, and nuclear magnetic resonance spectroscopy . No hypochromicity could be detected on mixing polymers 1-4 with poly(adenylic acid) . The acrylic acid copolymer 2 containing a high ratio of vinyluracil was a potent inhibitor of poly(adenylic acid) coded polylysine synthesis in an in vitro system . Polymers 6 and 7, containing a high proportion of vinyladenine, inhibited poly(uridylic acid) coded poly(phenylalanine) synthesis.

J Pharmacol Exp Ther, 1977 Oct, 203(1), 47 - 55
Evidence for a centrally mediated hypotensive effect of Escherichia coli endotoxin in the anesthetized dog; Dobbins DE et al.; The centrally mediated cardiovascular effects of Escherichia coli endotoxin were studied utilizing a neurally intact vascularly isolated head-trunk preparation in the anesthetized dog . The vascularly isolated head was perfused at constant flow with arterial blood supplied by a donor animal . Spectrophotometric examination of the donor and recipient trunk blood after administration of Evan's blue dye indicated that there was no blood exchanged between the head and trunk of the recipient dog . The responses to various physiological maneuvers and denervations indicated that the central nervous system and all afferents and efferents involved in the control of the cardiovascular system were functioning normally . The infusion of purified E . coli endotoxin into the arterial perfusion circuit to the head, either before or after bilateral denervation of the carotid sinus-body complexes, resulted in marked hypotension within 30 minutes in the trunk of the recipient dog . These findings indicate that purified E . coli endotoxin is capable of eliciting marked centrally mediated hypotensive responses . The time course of these responses suggests that the centrally mediated hypotensive effects of endotoxin do not participate in the initial precipitous fall in blood pressure seen after systemic administration of endotoxin, but rather that they may contribute significantly to the maintenance of the hypotension.

J Natl Cancer Inst, 1977 Oct, 59(4), 1061 - 3
L-asparagine requirements of human T-lymphocytes and B-lymphocytes in culture; Ohnuma T et al.; The characterization of two human T-lymphocyte lines revealed that they required exogenous L-asparagine for cell growth, whereas all four B-cell lines studied were L-asparagine independent . T-cells were 800-2,000 times more sensitive to Escherichia coli L-asparaginase than were B-cells . The cytotoxic effects of a high concentration of L-asparaginase on B-cells were not related to the hydrolysis of L-asparagine but were due to heat-labile and heat-resistant substances in the enzyme . The findings were consistent with reports that L-asparaginase is effective in suppressing cellular immunity and inducing remission in patients with acute lymphocytic leukemia, mainly a non-B-cell disease . Thus these cell lines provide in vitro models for the study of a nutritional approach to chemotherapy or immunotherapy.

Proc Natl Acad Sci U S A, 1977 Oct, 74(10), 4195 - 9
Synthesis of phiX174 viral DNA in vitro depends on phiX replicative form DNA; Sumida-Yasumoto C et al.; A cell-free system that catalyzes phiX174 replicative form I (supercoiled circular duplex, RFI)-dependent phiX174 DNA synthesis has been isolated from Escherichia coli infected with phiX174 phage . The products formed with such preparations are viral strands as judged by hybridization to poly(U,G) followed by equilibrium centrifugation in CsCl . This phiX174 DNA-synthesizing involves formation of DNA-protein complexes that sediment in neutral sucrose with S values of 50, 60-70, and higher . The 50S complex contained a rolling-circle replicative intermediate DNA with an extended tail of single-stranded viral DNA . The DNA contained in the 60-70S region was a mixture of circular and linear single-stranded DNA, RFI, and RFII with an extended single-stranded tail . Such complexes have been isolated during in vivo progeny phiX174 DNA synthesis {Fujisawa, H . & Hayashi, M . (1976) J . Vriol . 19,409} . In vitro, maximal phiX174 DNA synthesis was shown to require the genetically defined proteins E . coli dna B, dna C, dna G, dna Z, rep . phiX174 gene A product, and other phiX174 coded proteins . The synthesis of phiX174 DNA is ATP-dependent and is inhibited by nalidixic acid and novobiocin but is resistant to rifampicin.

Can J Microbiol, 1977 Oct, 23(10), 1384 - 93
Isolation and characterization of catabolite repression-resistant mutants of Escherichia coli; Armstrong GD et al.; A method has been developed for the isolation of Escherichia coli mutants which are resistant to catabolic repression . The method is based on the fact that a mixture of glucose and gluconate inhibits the development of chemotactic motility in the wild type, but not in the mutants . A motile E . coli strain was mutagenized and grown in glucose and gluconate . Mutants which were able to swim into a tube containing a chemotactic attractant (aspartic acid) were isolated . Most of these mutants were able to produce beta-galactosidase in the presence of glucose and gluconate and were normal in their ability to degrade adenosine 3',5-cyclic monophosphate . Some of these mutants were defective in the glucose phosphotransferase system.

Acta Med Okayama, 1977 Oct, 31(5), 275 - 87
Thermal denaturation and template activities of reconstituted DNA-histone complexes; Oda T et al.; Reconstituted complexes of DNA with histone were prepared by salt-and-urea step gradient dialysis . The DNA was complexed with histone H1, with the combination of the other four histones H2A, H2B, H3 and H4, and with whole histones . These DNA-histone complexes were purified by Bio-Gel column chromatography, and the weight ratio of histone-to-DNA was determined in each complex . The thermal denaturation profile and nuclease digestion pattern of DNA-histone H2A, H2B, H3 and H4 complex were compatible with those of the polynucleosome structure of chromatin . The template activities for transcription were compared in these DNA-histone complexes by separately measuring initiation reaction and chain elongation . The binding of histone H1 to DNA strongly inhibited the initiation, while the binding of the combination of the other four histones to DNA partially inhibited the initiation and chain elongation . The binding characteristics are discussed with regard to the role of histone H1 and the other four histones in chromatin structure and template activity.

Proc Natl Acad Sci U S A, 1977 Oct, 74(10), 4160 - 2
Action of nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and nicotinamide mononucleotide; Brunngraber EF et al.; The action of the nucleotide phosphotransferase of Escherichia coli on nicotinamide riboside and on its 5'-phosphate results in the addition of one phosphate moiety to each of the substrates . Although the proof is not conclusive, it is likely that the phosphate group is transferred to the 3'-hydroxyl of the ribose . This is in contrast to the behavior of the enzyme toward NAD in which only the adenylic acid portion is phosphorylated enzymically.

J Gen Microbiol, 1977 Oct, 102(2), 327 - 36
The enzymic interconversion of acetate and acetyl-coenzyme A in Escherichia coli; Brown TD et al.; Mutants of Escherichia coli K12 have been isolated that grow on media containing pyruvate of proline as sole carbon sources despite the presence of 10 or 50 mM-sodium fluoroacetate . Such mutants lack either acetate kinase {ATP: acetate phosphotransferase; EC 2.7.2.1} or phosphotransacetylase {acetyl-CoA: orthophosphate acetyltransferase; EC 2.3.1.8} activity . Unlike wild-type E . coli, phosphotransacetylase mutants do not excrete acetate when growing aerobically or anaerobically on glucose; their anaerobic growth on this sugar is slow . The genes that specify acetate kinase (ack) and phosphotransacetylase (pta) activities are cotransducible with each other and with purF and are thus located at about min 50 on the E . coli linkage map . Although Pta- and Ack- mutants are greatly impaired in their growth on acetate, they incorporate {2-14C}acetate added to cultures growing on glycerol, but not on glucose . An inducible acetyl-CoA synthetase {acetate: CoA ligase (AMP-forming); EC 6.2.1.1} effects this uptake of acetate.

J Biol Chem, 1977 Sep 25, 252(18), 6421 - 3
Purification and properties of superoxide dismutase from a red alga, Porphyridium cruentum; Misra HP et al.; The major superoxide dismutase of the unicellular red alga, Porphyridium cruentum, has been purified to homogeneity . This enzyme has a molecular weight of 40,000 and is composed of two subunits of equal size, which are joined by noncovalent interactions . Manganese constituted 0.13% of this superoxide dismutase . T,is is equivalent to 1 manganese atom/molecule of enzyme . Cyanide at 5 mM and H2O2 at 3 mM had no effect on the activity of this superoxide dismutase but 20 mM azide caused 50% inhibition . The isoelectric point, assessed by isoelectric focusing, is 4.2 . The optical spectrum of this enzyme exhibited a maximum at 280 nm (Em = 49,000 M-1 cm-1) and a broad band centered at 450 nm (Em = 170 M-1 cm-1) . Exposure to a pH of 3.8 in the presence of 8.0 M urea labilized the manganese and allowed the preparation of a colorless and inactive apoenzyme which could be reconstituted by subsequent treatment with MnCl2 . The reconstituted enzyme was found to have regained both manganese and activity . The amino acid composition was also determined . The P . cruentum superoxide dismutase did not cross-react with antibody to the Escherichia coli manganese-containing superoxide dismutase.

J Biol Chem, 1977 Sep 25, 252(18), 6562 - 71
Organization of the yeast ribosomal RNA gene cluster via cloning and restriction analysis; Nath K et al.; The restriction endonuclease EcoR1 cleaves Saccharomyces cerevisiae DNA, which codes for ribosomal RNA (rRNA), into seven fragments, A second restriction endonuclease, HindIII, cleaves the same yeast ribosomal DNA into two fragments . These two restriction enzymes each yield DNA segments that total about 5.9 megadaltons . The "repeat unit" of the yeast genes coding for rRNA is thus about 5.9 megadaltons or about 9000 base pairs long . The two HindIII-cleaved DNA fragments as well as one of the EcoR1-cleaved DNA fragments were purified and amplified by cloning in Escherichia coli . Three of the seven EcoR1-generated DNA fragments could then be ordered by treating the two cloned HindIII DNA fragments with EcoR1 . This led the assignment of the two HindIII restriction sites . The various restriction DNA fragments were hybridized directly from the gel utilizing 32P-labeled 5 S, 5.8 S, 18 S, and 25 S rRNA . Identification of the various DNA restriction segments then led to the final ordering of the DNA fragments . The gene coding for the 5 S RNA is adjacent to the gene coding for the 35 S precursor rRNA . These two groups of genes thus occur as a cluster in the following sequence: {5 S-spacer}-{spacer-18 S-5.8 S-25 S-spacer}-{spacer-5 S} . The actual map of the DNA restriction fragments is presented.

J Biol Chem, 1977 Sep 25, 252(18), 6478 - 84
DNA polymerase III holoenzyme of Escherichia coli . Purification and resolution into subunits; McHenry C et al.; DNA polymerase III holoenzyme has been purified from Escherichia coli HMS-83, using, as an assay, the conversion of coliphage G4 single-stranded DNA to the duplex replicative form . The holoenzyme consists of at least four different subunits: alpha, beta, gamma, and delta of 140,000, 40,000, 52,000, and 32,000 daltons, respectively . The alpha subunit is DNA polymerase III, the dnaE gene product . The holoenzyme has been resolved by phosphocellulose chromatography into an alpha - gamma - delta complex and a subunit beta (copolymerase III*); neither possesses detectable activity in the G4 system but together reconstitute holoenzyme-like activity . The alpha - gamma - delta complex has been further resolved to yield a gamma - delta complex which reconstitutes alpha - gamma - delta activity when added to DNA polymerase III . The gamma - delta complex contains a product of the dnaZ gene and has been purified from a strain which contains a ColE1-dnaZ hybrid plasmid.

J Biol Chem, 1977 Sep 25, 252(18), 6367 - 72
Purification of thioredoxin, thioredoxin reductase, and glutathione reductase by affinity chromatography; Pigiet VP et al.; A scheme is described for the large scale purification of thioredoxin, thioredoxin reductase, and glutathione reductase . The scheme is based on an initial separation of thioredoxin from the two reductases by affinity chromatography on agarose-bound N6-(6-aminohexyl)-adenosine 2',5'-bisphosphate (agarose-2',5'-ADP) . The two reductases were then separated by hydrophobic chromatography and purified separately to homogeneity . Thioredoxin was purified to homogeneity by immunoadsorption to agarose containing immobilized goat anti-thioredoxin . Overall yields for thioredoxin, thioredoxin reductase, and glutathione reductase exceeded 80% in each case . Both reductases exhibit an absorption band at approximately 320 nm which appears due to a residual amount of tightly bound NADP . Presence of this absorption band has no apparent effect on the specific activity of either enzyme.

J Biol Chem, 1977 Sep 25, 252(18), 6299 - 303
Identification of UDP-glucose as an intermediate in the biosynthesis of the membrane-derived oligosaccharides of Escherichia coli; Schulman H et al.; The membrane-derived oligosaccharides of Escherichia coli constitute a closely related family of oligosaccharides containing approximately 9 glucose units variously substituted with sn-glycero-1-phosphate and phosphoethanolamine residues derived from the head groups of membrane phospholipids, and also with succinate in O-ester linkage (Kennedy, E.P., Rumley, M.K., Schulman, H., and van Golder, L.M.G . (1976) J . Biol . Chem . 251, 4208-4213) . Studies with mutant strains defective in the synthesis of various nucleoside diphosphate sugars have now revealed that UDP-glucose is an essential intermediate in the biosynthesis of these oligosaccharides . Mutants unable to synthesize UDP-glucose do not contain significant amounts of the membrane-derived oligosaccharides . In contrast, a strain unable to synthesize ADP-glucose, the glucosyl donor for glycogen synthesis in E . coli, contained normal amounts of the membrane-derived oligosaccharides, although with a somewhat different pattern of distribution of the various subspecies . In confirmation of these genetic studies, pulse-label isotope tracer studies have been carried out with glucose of high specific activity, under conditions in which UDP-glucose comprises a large fraction of the total radioactivity in the low molecular weight pool . Subsequent "chase" experiments clearly revealed the conversion of UDP-glucose to the higher molecular weight membrane-derived oligosaccharides.

J Biol Chem, 1977 Sep 25, 252(18), 6251 - 2
Escherichia coli protein X is the recA gene product; Little JW et al.; Escherichia coli protein X is known to be made in large amounts following DNA damage or inhibition of DNA replication . We have shown that it is identical to the recA gene product by partial proteolytic digestion of the radiochemically pure proteins and analysis by electrophoresis on polyacrylamide-sodium dodecyl sulfate gels.

Mol Gen Genet, 1977 Sep 21, 155(1), 7 - 18
Transcription of the argF and argI genes of the arginine biosynthetic regulon of Escherichia coli K12, performed in vitro; Sens D et al.; The cell-free transcription of the argF and argI genes of the arginine biosynthetic regions is described using an S-30 system capable of coupled in vitro transcription-translation . Template DNA isolated from two independently isolated arginine transducing phages was used in this work . Steady state mRNA synthesis was observed which was attributed to RNAase degradation . Regulation of argF mRNA synthesis, directed by the argF gene carried on the specialized transducing phage phi80dargF is effected to the extent of at least 95% by the arginine holorepressor at the transcriptional stage and at least 80% of the regulation of the expression of the argI gene is mediated at the transcriptional stage . Evidence is presented which indicates that the arginine holorepressor prevents RNA polymerase from binding to the arginine promoter and suggests that the operator and promoter sites may overlap.

Mol Gen Genet, 1977 Sep 21, 155(1), 61 - 5
Regulation of the intracellular concentration of T4 induced tRNA; Fario M et al.; We have studied the biosynthesis of T4 induced tRNA's upon infection of E . coli BE cells in low phosphate (l.p.) medium (10(-4) M PO---4) . Under out experimental conditions the onset of phage DNA synthesis occurs about 15 min after infection, while the first intracellular phage appears one hour later . Amounts of newly synthesized DNA and phage burst size are equivalent to the values obtained in standard (M9) medium (10(-1) M PO---4) . We present evidence that the synthesis of mature tRNA's and of at least one dimeric precursor drastically declines 20 min after infection . In addition we show that T4 induced tRNA molecules are stable and that the triphosphate nucleoside precursor pool does not change significantly during infection . Therefore we conclude that T4 induce tRNA molecules behave similarly to other early gene products.

J Chromatogr, 1977 Sep 21, 139(2), 331 - 6
Use of omega-aminohexyl-sepharose in the fractionation of Escherichia coli B aminoacyl-tRNA synthetases; Jakubowski H; The usefulness of aminohexyl-Sepharose in purification of E . coli B aminoacyl-tRNA synthetases is presented . The purification factors for 14 synthetases lie in the range 3- to 94-fold and the recoveries of the enzymatic activity were 30-80%, depending on the enzyme.

Mol Gen Genet, 1977 Sep 21, 155(1), 93 - 102
On the structure of the deo operon of Escherichia coli; Jorgensen P et al.; A characterization of a specialized transducing lambda phage for the deo operon (lambdaddeo), and some composite colE1-deo plasmids is given in this paper . This includes localization of the RSmaI, RHind/III, RBamI, and REcoRI sensitive sites . The deo genes have been localized by construction of composite colE1-deo plasmids . Using the DNA fragments, obtained by digestion with REcoRI and RHindIII, respectively, as templates in an in vitro protein synthesizing system, it has been possible to give the direction of transcription and the exact location of the deo genes, relative to the endonuclease sites . Furthermore, the cytO,P and deoO,P regions have been mapped relative to the structural genes . Supercoiled co1E1-deo DNA has been used as template in the in vitro system; this DNA gives essentially the same results as the endonuclease-fragmented DNA . The use of the different types of templates is discussed.

Mol Gen Genet, 1977 Sep 21, 155(1), 53 - 60
Interaction of the cytoplasmic membrane and ribosomes in Escherichia coli; altered ribosomal proteins in sucrose-dependent spectinomycin-resistant mutants; Dombou M et al.; Alterations in the ribosomes of sucrose-dependent spectinomycin-resistant (Sucd-Spcr) mutants of Escherichia coli were studied . Subunit exchange experiments showed that 30S subunits were responsible for the resistance of ribosomes to spectinomycin in all Sucd-Spcr mutants tested . Proteins of 30S ribosomes were analyzed by carboxymethyl cellulose column chromatography based on their elution positions . Mutants YM22 and YM93 had an altered 30S ribosomal protein component, S5, and mutant YM50 had an altered protein, S4 . Although a shift of elution position was not detected for all the 30S ribosomal proteins from mutant YM101, the amount of protein S3 was appreciably lowered in the isolated 30S subunits . A partial reconstitution experiment with protein S3 prepared from both the wild-type strain and YM101 revealed that the mutant had altered protein S3 which is responsible for the spectinomycin resistance . These alterations in 30S subunits are discussed in relation to the interaction between ribosomes and the cytoplasmic membrane.

Biochim Biophys Acta, 1977 Sep 20, 478(2), 215 - 23
Induction of alkaline phosphatase in Escherichia coli . Effect of phenethyl alcohol; Tribhuwan RC et al.; Induction of alkaline phosphatase, an enzyme located in the periplasmic region of Escherichia coli, was inhibited by phenethyl alcohol, an agent believed to alter the cell membrane structure . Studies to elucidate mechanism of this inhibition showed that while phenethyl alcohol arrested the incorporation of {3H}leucine into active alkaline phosphatase, it did allow substantial incorporation of the label into inactive monomer subunits of the enzyme . These results suggest that phenethyl alcohol may not interfere with the de novo synthesis of monomer subunits of the enzyme but arrest conversion of these into active dimer enzyme presumably by its primary action on the cell membrane structure.

Biochemistry, 1977 Sep 20, 16(19), 4270 - 5
pH-dependent changes in proton:substrate stoichiometries during active transport in Escherichia coli membrane vesicles; Ramos S et al.; Experiments are presented in which the proton electrochemical gradient (deltamuH+) IN Escherichia coli membrane vesicles (interior negative and alkaline) was measured under a variety of conditions and compared with steady-state levels of accumulation of lactose, proline, D-lactate, and glucose-6-P measured under identical conditions . Accumulation of lactose and proline is proportional to the magnitude of deltamuH+ at pH 5.5, where the pH gradient (deltapH) and the electrical potential (deltapsi) both contribute to deltamuH+, and at pH 7.5, where deltapsi represents the only component of deltamuH+ . Moreover, the proportionality constants between deltamuH+ and lactose or proline accumulation indicate that the proton:substrate stoichiometries are 1:1 at pH 5.5 and 2:1 at pH 7.5 . Evidence is also presented which indicates that the functional group responsible for the increase in proton:proline stoichiometry has a pK of approximately 6.8 . Accumulation of D-lactate and glucose-6-P is directly related to the magnitude of deltapH at pH 5.5, and stoichiometry values of one and approximately 1.7 are obtained for D-lactate and glucose-6-P, respectively, at this pH . At pH 7.5, on the other hand, accumulation of each organic acid bears a linear relationship to deltapsi, and proton:substrate stoichiometries of unity are observed in both instances . The results are consistent with the models discussed by Rottenberg (Rottenberg, H . (1976), FEBS Lett . 66, 159).

Biochim Biophys Acta, 1977 Sep 19, 469(3), 326 - 34
Kinetics of phospholipid exchange between bilayer membranes; Thilo L; In an accompanying publication by Duckwitz-Peterlein, Eilenberger and Overath ((1977) Biochim . Biophys . Acta 469,311--325) it is shown that the exchange of lipid molecules between negatively charged vesicles consisting of total phospholipid extracts from Escherichia coli occurs by the transfer of single lipid monomers or small micelles through the water . Here a kinetic interpretation is presented in terms of a rate constant, k--, for the escape of lipid molecules from the vesicle bilayer into the water . The evaluated rate constants are kP- = (0.86 +/- 0.05) - 10(-5) S-1 and ke- = (1.09 +/- 0.13) - 10(-6) s-1 for phospholipid molecules with trans-delta 9-hexadecenoate and trans-delta 9-octadecenoate, respectively, as the predominant acyl chain component . The rate constants are discussed in terms of the acyl chain and polar head group composition of the lipids.

Biochim Biophys Acta, 1977 Sep 19, 469(3), 311 - 25
Phospholipid exchange between bilayer membranes; Duckwitz-peterlein G et al.; The mode of interaction of aqueous dispersions of phospholipid vesicles is investigated . The vesicles (average diameter 950 A) are prepared from total lipid extracts of Escherichia coli composed of phosphatidylethanolamine, phosphatidylglycerol and cardiolipin . One type of vesicle contains trans-delta 9-octadecenoate, the other type trans-delta 9-hexadecenoate as predominant acyl chain component . The vesicles show order in equilibrium disorder transitions at transition temperatures, Tt = 42 degrees C and Tt = 29 degrees C, respectively . A mixture of these vesicles is incubated at 45 degrees C and lipid transfer is studied as a function of time using the phase transition as an indicator . The system reveals the following properties: Lipids are transferred between the two vesicle types giving rise to a vesicle population where both lipid components are homogeneously mixed . Lipid transfer is asymmetric, i.e . trans-delta 9-hexadecenoate-containing lipid molecules appear more rapidly in the trans-delta 9-octadecenoate-containing vesicles than vice versa . At a given molar ratio of the two types of vesicles the rate of lipid transfer is independent of the total vesicle concentration . It is concluded that lipid exchange through the water phase by way of single molecules or micelles is the mode of communication of these negatively charged lipid vesicles.

Eur J Biochem, 1977 Sep 15, 79(1), 56 - 72
Small-angle X-ray titration study on the complex formation between 5-S RNA and the L18 protein of the Escherichia coli 50-S ribosome particle; Osterberg R et al.; The 5-S RNA (A) and the L18 protein (B) from Escherichia coli ribosomes form one single AB complex in the concentration ranges supposed to prevail in vivo; at concentrations of L18 higher than 40 mM there is some indication for a minor species, most probably an AB2 species . This is indicated from the X-ray scattering titration data of the 5-S RNA/L18 system recorded at 21 degrees C in ribosomal reconstitution buffer . As a result of the 1:1 complex formation, there is a relatively small but defined increase in the radius of gyration from 3.61 to 3.85 nm . This result as well as the experimental scattering curve can be explained by models where it is assumed that the elongated L18 model is quite far from the electron density centre and where protein L18 interacts with one or both of the minor arms of the supposed Y-shaped 5-S RNA molecule.

Eur J Biochem, 1977 Sep 15, 79(1), 93 - 102
Further evidence that elongation factor 1 remains bound to ribosomes during peptide chain elongation; Grasmuk H et al.; This paper describes three types of experiments which indicate that the binding sites for elongation factor 1 (EF-1) and elongation factor 2 (EF-2) on ascites cell ribosomes are not identical and perhaps not even overlapping . The experimental evidence presented includes direct competitive binding of labeled elongation factors to ribosomes as well as the influence of pokeweed antiviral protein and Escherichia coli anti L7/L12 proteins on the binding and function of the two factors . It is further shown that EF-1beta from Artemia salina does not function in displacing EF-1 from mouse ascites tumor cell ribosomes . These results also support our recently proposed model that EF-1 remains bound to the ribosome during the peptide chain elongation cycle.

Eur J Biochem, 1977 Sep 15, 79(1), 39 - 45
DNA unwinding enzyme II of Escherichia coli . 2 . Characterization of the DNA unwinding activity; Abdel-Monem M et al.; The DNA-stimulated 75000-Mr ATPase described in the preceding paper is shown to be a further catalytic DNA unwinding principle (DNA unwinding enzyme II) made in Escherichia coli cells (the first being the 180000-Mr ATPase of the cells: DNA unwinding enzyme I) . Unwinding depends strictly, on the supply of ATP . It occurs only under conditions permitting ATP dephosphorylation and it proceeds as long as enzyme molecules are permitted to enter the enzyme - DNA complex . The enzyme binds specifically to single-stranded DNA yielding a complex of only limited stability . These results are interpreted in terms of a distributive mode of action of the enzyme . It is argued that chain separation starts near a single-stranded DNA region and that, forced by continued adsorption of enzyme molecules to the DNA, it develops along the duplex . This mechanism is different from that deduced previously for DNA unwinding enzyme I . Complicated results were obtained using ATPase prepared from rep3 mutant cells.

Eur J Biochem, 1977 Sep 15, 79(1), 33 - 8
DNA unwinding enzyme II of Escherichia coli . 1 . Purification and characterization of the ATPase activity; Abdel-Monem M et al.; A DNA-stimulated ATP-gamma-phosphohydrolase of molecular weight 75000 was purified from Escherichia coli cells . The ATPase, a globular molecule (identical probably with an ATPase described previously by Richet and Kohiyama in 1976) shows specificity for adenine nucleotides, it prefers single-stranded DNA as the cofactor, it exhibits a complicated mode of response to variations of the cofacter concentration and it is devoid of nuclease activity . Preparations derived from rep3 mutant cells yield widely varying amounts of an apparently normal ATPase.

Biochim Biophys Acta, 1977 Sep 15, 484(1), 35 - 48
Two Escherichia coli fructose-6-phosphate kinases . Preparative purification, oligomeric structure and immunological studies; Kotlarz D et al.; Two isoenzymes of fructose-6-phosphate kinase (ATP: D-fructose-6-phosphate 1-phosphotransferase, EC 2.7.1.11) are present in Escherichia coli K12 . One isoenzyme is allosterically inhibited by phosphoenolpyruvate and activated by nucleoside diphosphates, and is a tetramer composed of four subunits of molecular weight 35 000 . A simple method for the purification of this enzyme is reported . Equilibrium dialysis indicates that there are four ATP sites and four GDP sites per tetramer . The second isoenzyme is present in low quantity in wild type bacteria . This enzyme is devoid of allosteric properties . A complete method of purification is described . Determination of its molecular weight under native and denaturing conditions indicates that this protein is a dimer composed of two subunits of molecular weight 36 000 . Antisera have been produced against both isoenzymes . The antiserum against one isoenzyme does not cross-react with the other . Discrepancies between our results and those of other workers are discussed.

Biochim Biophys Acta, 1977 Sep 15, 484(1), 244 - 8
A conformational change in phosphoglycerate dehydrogenase induced by a shift in pH; Dubrow R et al.; The fluorescence of NADH bound to phosphoglycerate dehydrogenase (3-phosphoglycerate: NAD+ oxidoreductase, EC 1.1.1.95) decreased by 42% between pH 8.5 and 7.0 Serine, an allosteric inhibitor, quenched the fluorescence of enzyme-bound NADH by 29% at pH 8.5, but not at all at pH 7.0 . The kinetics of the fluorescence change which occurred when the pH of an enzyme-NADH solution was rapidly shifted from 8.5 to 7.0 was measured using stopped-flow fluorimetry . The kinetics were first order, with a rate constant of 2.83 s-1 . This rate constant was similar in magnitude to the rate constants for fluorescence quenching at pH 8.5 by saturating concentrations of serine and glycine, another allosteric inhibitor (Dubrow, R . and Pizer, L.I . (1977) J . Biol . Chem . 252, 1527-1538) . These results indicate that the conformation of phosphoglycerate dehydrogenase at pH 7.0 is similar to, but not identical with, the serine-induced conformation at pH 8.5.

Vet Rec, 1977 Sep 10, 101(11), 196 - 9
Breeding record analysis in pig herds and its veterinary applications--2: Experiences with a large commercial unit; Pepper TA et al.; A computer program was used to analyse data from a large commercial pig unit over two years to assess reproductive efficiency and the efficiency of weaner production . Monthly inspections of the farm and quarterly post mortem examinations of all dead pigs provided further information . The effects of controlled changes in management on production were assessed . Overall the number of piglets reared per sow per year was increased from 15-1 to 17-2 and the eight-week weights improved from a mean of 10-3 kg to 15-0 kg during the two year-study period.

J Biol Chem, 1977 Sep 10, 252(17), 5928 - 30
Regulation of Escherichia coli ornithine transcarbamylase by orotate; Knight DM et al.; Ornithine transcarbamylase from Escherichia coli, strain W, exhibits negative cooperativity with respect to ornithine, and the enzymatic activity is further regulated by orotate . The effect of orotate on ornithine transcarbamylase is dependent not only upon the carbamylphosphate concentration, but also upon the concentration of ornithine . At high concentrations of carbamylphosphate (10 mM), a conversion from negative cooperativity to positive cooperativity is observed with 10 mM orotate . At 1 mM carbamylphosphate, however, 10 mM orotate activates the enzyme at low ornithine concentrations, but as the ornithine concentration is increased above 5 mM, inhibition is observed . Thus, a regulatory link has been established between the pathways of arginine biosynthesis and pyrimidine biosynthesis, each of which utilizes carbamylphosphate.

Mol Gen Genet, 1977 Sep 9, 154(3), 335 - 6
Antimutagens against mutT; Clarke CH et al.; In E . coli strain 91P containing the mutator gene mutT-, caffeine, spermine and quinacrine, but not guanosine, act as antimutagens, reducing the frequencies of mutation from ara- leads to Ara.

Mol Gen Genet, 1977 Sep 9, 154(3), 327 - 34
Synthesis of ribosomal proteins in merodiploid strains and in minicells of Escherichia coli; Geyl D et al.; Merodiploid strains of Escherichia coli containing episomes which carry one or several of the ribosomal protein (r-protein) transcriptional units were analysed to see whether the increase in the number of gene copies leads to an increased synthesis of the respective r-proteins . It was found that the amount of ribosomal proteins was (with the only exception of ribosomal protein S20) independent of the number of gene copies present . The comparison of the in vivo stability of r-proteins in haploid and merodiploid strains did not, within the time resolution of the experiment, provide any evidence for an increased rate of degradation of those proteins coded by more than one gene copy . These results indicate a tight coupling between the amount of ribosomal proteins synthesized and the level required irrespective of the number of gene copies present . With the aid of minicells from a strain containing the episome F'101 which carries the thr-leu segment of the chromosome it was demonstrated that (i) in vivo synthesis of r-protein S20 could proceed in the absence of the synthesis of ribosomal RNA and of other r-proteins, and (ii) r-protein S20 was degraded under conditions where it was not assembled into ribosomes.

Mol Gen Genet, 1977 Sep 9, 154(3), 305 - 9
Insertion of the tetracycline resistance translocation unit Tn10 in the lac operon of Escherichia coli K12; Foster TJ; The majority of TN10 insertions in the lacZ gene of Escherichia coli occurred in a small region of the promoter distal part of the gene . The resulting mutations were polar on lacY and reverted to Lac+ at a frequency of 10(-8) . None of the revertants were Tcr . Furthermore Lac+ Tcr revertants could not be selected directly . Relief of polarity revertants of the lacZ::Tn10 mutants were formed at a frequency of 10(-5) - 10(-4) . Most resulted from a deletion event internal to the transposon which removed the Tcr genes and the putative transcription terminator . It is postulated that a fragment of Tn10 remains at the original insertion point to cause a revertible Lac- mutation.

Mol Gen Genet, 1977 Sep 9, 154(3), 287 - 92
Prophage induction in Escherichia coli K12 cells deficient in DNA polymerase I; Blanco M et al.; The induction of prophage lambda by ultraviolet light has been measured in E . coli K12 lysogenic cells deficient in DNA polymerase I . The efficiency of the induction process was greater in polA1 polC(dnaE) double mutants incubated at the temperature that blocks DNA replication than in polA+ polC single mutants . Similarly, the polA1 mutation sensitized tif-promoted lysogenic induction in a polA1 tif strain at 42 degrees . In strains bearing the polA12 mutation, which growth normally at 30 degrees, induction of the prophage occurred after the shift to 42 degrees . It is concluded that dissapearance of the DNA polymerase I activity leads to changes in DNA replication that are able, per se, trigger the prophage induction process.

Mol Gen Genet, 1977 Sep 9, 154(3), 279 - 85
Gene affecting longevity of messenger RNA: a mutant of Escherichia coli with altered mRNA stability; Kuwano M et al.; We have screened 897 temperature sensitive growth mutants of E . coli for mutant strains showing longer mRNA half-life . The fate of pulse-labelled RNA was examined at 42 degrees C after cessation of RNA synthesis and with prior exposure to nonpermissive temperature (42 degrees C) . Eight stains showed altered turnover of RNA (presumably mRNA), and further analysis on mutant strain JE15144 indicated that the stability of pulse-labeled RNA as well as of tryptophan (trp) mRNA increased four to seven fold over its parental strain at 42 degrees C . At 4 min or 10 min after addition of rifampicin, some 70 to 80% of polyribosome in the growing cells could still be conserved in JE15144 cultured at the nonpermissive temperature while little, if any, polyribosomes remained in its parental strain (PA3092) under the same condition . Two generation times were required for complete stoppage of growth of this mutant strain after shifting to 42 degrees C, and protein synthesis continued at a significant, but slightly reduced, rate at 42 degrees C . However, functional decay of mRNA in the mutant strain, with respect to the capacity for producing peptides, appeared to be similar to the parent strain, with half-lives of 3.5 min in PA3092 and 4.7 min in JE15144.

Mol Gen Genet, 1977 Sep 9, 154(3), 263 - 7
RNA-linked nascent DNA pieces in T7 phage-infected Escherichia coli cells . I . Role of gene 6 exonuclease in removal of the linked RNA; Shinozaki K et al.; The presence of RNA-linked nascent DNA pieces in T7 phage-infected Escherichia coli cells has been shown by the selective degradation of the 5'-hydroxyl-terminated nascent DNA, produced by alkali or RNase treatment, with spleen exonuclease . At 43 degrees C, the proportion of RNA-linked DNA pieces in nascent short dna is 50 to 60% in T7 ts136 (ts mutant of gene 6) phage-infected E . coli, whereas that in T7 wild-type phage-infected cells is less than 6% . Joining of the nascent pieces is greatly retarded in T7 ts136-infected E . coli temperature sensitive polA mutants at 43 degrees C . These results suggest that gene 6 exonuclease plays a role in removal of the linked RNA during the discontinuous replication of T7 DNA.

Mol Gen Genet, 1977 Sep 9, 154(3), 225 - 30
Replication of plasmid pSC101 in Escherichia coli K12: requirement for dnaA function; Hasunuma K et al.; Replication of pSC101 was analyzed by using DNA-DNA hybridization and alkaline sucrose gradient centrifugation . Mutants of the dnaA gene were tested for their capacity to replicate pSC101 DNA at a non-permissive temperature . Only a small amount of radioactive precursor was incorporated into pSC101 DNA in dnaA mutants at 42 degrees C whereas active incorporation into plasmid DNA took place in dnaA+ strain under the same conditions . The effect of the dnaA mutation was grater on plasmid DNA synthesis than on host chromosomal DNA synthesis . The numbers of copies of pSC101 per chromosome in wild type and dnaA strains, grown at 30 degrees C, were about 8 and 2, respectively . These results indicate that the dna A gene product is required for the replication of pSC101 DNA.

Biochemistry, 1977 Sep 6, 16(18), 4014 - 20
Isolation and characterization of independently folding regions of the beta chain of Escherichia coli tryptophan synthetase; Hogberg-Raibaud A et al.; It had been reported previously that the beta2 subunit of Escherichia coli tryptophan synthetase {L-serinehydrolyase (adding indole) EC 4.2.1.20} can be cleaved by trypsin into a nearly functional dimeric protein, the monomer of which consists of two large, nonoverlapping, polypeptide fragments . In the present paper, it is shown that these fragments can be separated after denaturation . Upon removal of the denaturing agent, the isolated fragments spontaneously refold into conformation, which, by various physical-chemical criteria, are shown to approximate the conformations of the corresponding fragments associated within the native protein . Furthermore, it is demonstrated that, upon mixing, these renatured fragments reassociate to form the renatured nicked protein which, by all the physical and functional criteria used, is indistinguishable from the native nicked protein . These results are taken as strong evidence that the isolated fragments can be considered as independently folding regions corresponding to intermediates in the folding of the intact protein.

Biochim Biophys Acta, 1977 Sep 6, 478(1), 68 - 74
Lutropin stimulation of RNA synthesis in corpus luteum chromatin; McKerns KW et al.; Lutropin and human choriogonadotropin stimulated the endogenous chromatin-associated polymerase activity in purified chromatin prepared from nuclei of bovine corpus luteum . Chromatin was incubated in two different buffer systems: one that mainly supports the activity of polymerase I, another that supports the activity of polymerase II and is largely alpha-amanitin sensitive . The hormones lutropin and chorigonadotropin stimulated an increase in the rate of incorporation of {14C}ATP or {14C}UTP into RNA in both buffer systems . Follitropin, prolactin and beta-corticotropin had no stimulatory effect . Neither the alpha nor beta subunit of lutropin stimulated RNA synthesis . When premixed, the subunits rapidly formed the active molecule . A maximum response to RNA synthesis was achieved by a 10(-9) M concentration of human choriogonadotropin . Considerable activity was obtained at 10(-11) M human choriogonadotropin . There was no lutropin stimulation to RNA synthesis using calf thymus DNA and Escherichia coli RNA polymerase.

Biochim Biophys Acta, 1977 Sep 6, 478(1), 109 - 13
Unidirectional replication of the P-group plasmid RK2; Meyer RJ et al.; The mode of replication of the broad host-range plasmid RK2 has been determined from examination of molecular replicative forms cleaved with the restriction endonucleases EcoRI and Hind III . Replication is unidirectional, and proceeds from a unique origin . The location of the origin and other evidence suggests that genes involved in plasmid maintenance are not tightly clustered.

Biochim Biophys Acta, 1977 Sep 5, 469(2), 211 - 5
The role of enzyme I in the unmasking of an essential thiol of the membrane-bound enzyme II of the phosphoenolpyruvate-glucose phosphotransferase system of Escherichia coli; Haguenauer-Tsapis R et al.; The membrane-bound component of the phosphotransferase system of Escherichia coli, responsible for the phosphorylative uptake of methyl-alpha-D-glucoside has an essential thiol group which becomes available to inactivation by thiol reagents in the presence of the phosphate-accepting sugar or when phosphoenolpyruvate synthesis is inhibited . The form resistant to the thiol reagent requires not only the absence of sugar and an intact phosphoenolpyruvate generating system, but also an intact system generating phosphorylated Hpr which is impaired by heating of a thermosensitive enzyme I mutant.

Nucleic Acids Res, 1977 Sep, 4(9), 3065 - 81
Removal of 5'-terminal m7G from eukaryotic mRNAs by potato nucleotide pyrophosphatase and its effect on translation; Zan-Kowalczewska M et al.; The procedure for isolation of nucleotide pyrophosphatase (E.C . 3.6.1.9.) from potato has been modified to yield an endonuclease-free preparation purified 2300-fold . The enzyme was used for specific cleavage of pyrophosphate linkages in the 5'-terminal cap (m7GpppN) of several eukaryotic messenger RNAs . Enzymatic removal of 5'-terminal pm7G from reovirus, rabbit globin and Artemia salina mRNAs resulted in an almost complete loss (greater than 80%) of their template activities in a cell-free protein synthesizing system from wheat germ . Incubation with nucleotide pyrophosphatase did not decrease the translation of phage f2 RNA in an Escherichia coli cell-free system.

Mol Biol (Mosk), 1977 Sep-Oct, 11(5), 981 - 93
{Comparative study of the tRNA-methylases of normal and tumor tissues . I . Spectrum of renal and carcinoma RA methylases}; Deev VA et al.; A comparative study of rat kidney and carcinoma RA tRNA-methylase activity has been carried out using partially purified enzyme preparations and total E . coli tRNA . Also the nuclease activity of the methylase preparations from kidney and carcinoma was compared . It was established that the methylase activity in carcinoma preparations is higher, whereas the nuclease activity is lower in comparison to the enzyme preparations from liver . No formation of some specific methylated compounds could be established in the case of carcinoma . It was established that the relative contribution of individual methylases to the elevated level of total tRNA-methylase activity in carcinoma is different . Maximal enhancement of activity was established for the methylase forming m5U, whereas the activity of the enzymes, transfering the methyl group to the fifth position of C is practically equal in kidney and carcinoma tissues . Experimental results and theoretical evaluation of the hypotheses suggested to explain the higher methylase activity in tumor tissues allowed to reject some of them.

Mikrobiologiia, 1977 Sep-Oct, 46(5), 912 - 9
{Glucose transport system and regulation of gene expression in Escherichia coli}; Gershanovich VN et al.; The object of this work was to study the effect of mutations damaging protein components of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) of E . coli on the regulation of the activity of catabolite-sensitive operons . Mutations ptsI and ptsH affecting the activity of the enzyme I and HPr protein made the synthesis of catabolite-sensitive enzymes resistant to the action of glucose, and at the same time decreased the rate of transport of this compound . Mutation tgl affecting the activity of the glucose enzyme II lead to the same effect on the enzyme syntheses, though utilization was not altered in this case . The disturbance of beta-galactosidase synthesis in ptsI and ptsH mutants is due to interference of pts mutations into transcription of the lac operon at the lac promoter level . It is concluded that the proteins of the Escherichia coli PTS take part not only in glucose transport, but are also involved in the regulation of transcription of the catabolite sensitive operons.

Zentralbl Bakteriol {Orig B}, 1977 Sep, 165(1), 97 - 101
{Development of a new testmethod for surface disinfection procedures . VII . Proposal for the method (author's transl)}; Borneff J et al.; Based on the findings obtained from the previous experiments (information I-VI), a proposal is made for the examination of surface disinfection procedures under conditions roughly resembling those prevailing in practice . This test allows the action of the disinfectant to be calculated, while making due allowance for the natural rate of kill . The results of three tests with a liminally effective disinfectant concentration extensively agreed with each other . This permits the conclusion that the method has reached optimal standardization.

Carbohydr Res, 1977 Sep, 58(1), 73 - 8
The stereochemistry of the addition of glycerol to D-galactal, catalyzed by beta-D-galactosidase; Lehmann J et al.; On incubation with beta-D-galactosidase, D-galactal-2-d (1) plus glycerol yielded 1-deoxyglycerol-1-yl 2-deoxy-beta-D-lyxo-hexopyranoside-2(S)-d . By 1H-n.m.r . analysis, it was shown that the hydrogen atom introduced on C-2 is trans-related to the aglycon moiety . In contrast to this stereospecific, enzyme-catalyzed addition, the reaction of phenol with peracetylated 1, catalyzed by p-toluenesulfonic acid, which yields phenyl 3,4,6-tri-O-acetyl-2-deoxy-alpha-D-lyxo-hexopyranoside-2-d, was shown to entail both a trans and a cis addition.

Nucleic Acids Res, 1977 Sep, 4(9), 3123 - 42
The nucleotide sequence surrounding the origin of DNA replication of Col E1; Bastia D; The DNA of Col E1 replicates from a unique origin located at a distance of 17-19% of the genome length from the single Eco RI clevage site . The nucleotide sequence about this site has been determined by a combination of RNA and DNA sequencing techniques . The principal features of the sequence are two palindromes, one of which resembles a palindrome located in the intercistronic region of 0X174 . The sequence also contains stretches of purine and pyrimidine clusters of the following compositions: pAT5G, pC2T5G, pGT5G . The origin sequence demonstrates that initiation of DNA replication takes place in an intercistronic region of Col E1DNA, although the possibility that this region makes small polypeptides 30-40 residues long cannot be strictly eliminated at this time.

Am J Clin Nutr, 1977 Sep, 30(9), 1393 - 7
Polymorphonuclear neutrophilic leukocytes in protein deficiency; Felsenfeld O et al.; The number of white blood cells and of polymorphonuclear leukocytes remained unchanged in vervet monkeys (Cercopithecus aethiops) receiving a "O" protein diet . The motility of the polymorphonuclear leukocytes and their phagocytic and killing indices with and without leukokinin stimulation decreased in protein-depleted animals . Acid cathepsin decreased, DNA relatively increased, and peroxidase, alkaline phosphatase, acid phenylphosphatase, and lysozyme reached higher levels in the polymorphonuclear leukocytes of animals on a "O" protein diet.

Mol Biol (Mosk), 1977 Sep-Oct, 11(5), 1201 - 5
{Role of the N-terminal sequence (1-26) in the dimerization of protein L7 in solution}; Gudkov AT; Native protein L7 from E . coli ribosomes, oxidized protein and a fragment of protein L7 containing the sequence 27--120 obtained by cleavage of the native protein by cyanogen bromide were investigated by sedimentation analysis . It was found that protein L7 exists in solution in a dimer form while the protein oxidized by hydrogen peroxide and the fragment 27--120 do not form a dimer . On the basis of these investigations a conclusion is made that the ability for dimerization is stimulated by N-terminal regions of the protein L7 molecule.

Mol Biol (Mosk), 1977 Sep-Oct, 11(5), 1124 - 36
{Distribution of DNA sequences recognized by specific endonucleases}; Mashko SV et al.; The molecular weight distributions of fragments obtained after endonuclease treatment of DNA were studied . DNA's from pigeon and E . coli and restriction enzymes EcoRI and BamHI were used . The samples of 14C- and 3H-labelled DNA were treated by endonucleases, separated electrophoretically in 1% agatose gels, and radioactivity distributions along gels were measured . From these data weight and number distributions and the average molecular weights of DNA fragments were determined . EcoRI-fragments of phage DNA were used as standards for the molecular weight calibration . The experimental results are compared with the expected data calculated from the DNA GC content . The molecular weight distribution of fragments and the average molecular weights of BamHI-fragments of pigeon DNA and EcoRI- and BamHI-fragments of E . coli DNA differed from random ones . It is suggested that certain genomes contain regions in which the probability of endonuclease cleavage strongly differs from the average probability of such a cleavage for the entire genome.

Poult Sci, 1977 Sep, 56(5), 1468 - 71
The effect of starvation on antibody production of chicks; Nathan DB et al.; The effect of 24 and 48 hours of food and water deprivation on ascorbic acid, liver, leukocyte counts and internal lymphoid organ weights of crossbred chicks was examined . Starvation caused an increase in plasma ascorbic acid level, a significant decrease in leucocyte count in peripheral blood, significant loss in body weight and a profound loss in liver, bursa of fabricius, spleen and thymus weights . Deprived chicks were I.V . injected with Escherichia coli dead bacteria and sheep red blood cells at different times before and after onset of deprivation . Blood samples were taken 3, 6, and 12 days thereafter . A lower antibody titer was found on the 6th day post vaccination in the groups where deprivation started on the day before or on the day of vaccination.

Gene, 1977 Sep, 2(1), 55 - 8
Identification of the gal3 insertion in Escherichia coli AS IS2; Fiandt M et al.; The gal3 mutation in Escherichia coli, located in the operator-promoter region of the gal operon, is identified as an IS2 insertion in the polar orientation I relative to the direction of transcription . This mutation, which may be considered the earliest example of a polar mutation caused by an IS insertion, is shown by heteroduplex analysis of phage lambdagal3 to be located about 170 base pairs from the promoter-proximal end of the chlD-pgl deletion in lambdagal8 . It appears indistinguishable in position, sequence and orientation from the IS2 insertion carried by lambdagal8-490 . The endpoints of the bacterial DNA segments in lambdagal3 and lambdagal8 are physically mapped in relation to attL.

Zh Mikrobiol Epidemiol Immunobiol, 1977 Sep, (9), 36 - 40
{Highly specific agglutinating O- and OK-immunoglobulins for identification of Escherichia in the agglutination test on glass}; Ulisko IN et al.; Escherichia agglutinating O- and OK-immunoglobulins of class G were obtained by the method of ion exchange chromatography; in studying with live and heated O- and K- cultures of the test strains from the International escherichia collection these immunoglobulins proved to be diagnostically highly specific and useful for the identification of escherichia strains in the express agglutination reaction on glass.

Zentralbl Bakteriol {Orig A}, 1977 Sep, 239(1), 113 - 23
Gentamicin assay by enzymatic adenylylation and the application of a double osmotic shock procedure to prepare gentamicin adenine mono-nucleotide transferase; Dankert J et al.; The release of gentamicin adenine mono-nucleotide transferase (GAdT) during single cold osmotic shock treatment of E . coli K12 W677/HJR66 is not always maximal . The yield of GAdT could not be improved by using E . coli harvested at different stages of growth, by prolonging the exposure to the different steps of the shock procedure, by changing the sucrose concentration, or the magnesium chloride volume . The quantity of GAdT in osmotic extracts could be increased when a double shock procedure was performed . Using an aliquot (30 microliter) of the extract, an accurate and quick assay for gentamicin, sisomicin and tobramycin in microvolumes of serum (30 microliter) can be accomplished . To avoid high background activity in the assay, the extracts should be prepared from E . coli grown in gentamicin-free medium.

Vopr Med Khim, 1977 Sep-Oct, 23(5), 681 - 4
{Analysis of the cobalamin coenzymes in mouse splenic tumor cells}; Vares IuV et al.; Coabalamine coenzymes were studied in tumor spleen cells of mice with La leukosis . Endogenous cobalamines in the cell extracts were separated by two-dimensional thin-layer chromatography and by bioautography . Analysis of the cobalamines ratio was carried out using bioautochromatographic technique . 5-deoxyladenosyl- and methyl cobalamines were found in extracts of the tumor cells.

Res Vet Sci, 1977 Sep, 23(2), 185 - 90
Uptake of maternal antibody by the neonatal pig following intramuscular and intramammary vaccination of the preparturient sow; Chidlow JW et al.; Administration of heat inactivated Escherichia coli antigens by intramuscular and intramammary routes induced elevated antibody levels in sow serum and colostrum, predominantly associated with IgG . Colostral IgG accounted for approximately 80 per cent of the total antibody activity, and there was a similar distribution in the sera of one-day-old piglets . The additional antibody activity was carried almost entirely by IgM following intramuscular injections and was evenly distributed between IgM and IgA following intramammary stimulation . The distribution of antibody activity and all three major immunoglobulin classes in colostrum and milk from individual mammary glands was remarkably uniform . A similar uniformity was inferred for the ingestion and absorption of colostrum by individual piglets as judged by the contents of their blood sera during the neonatal period.

J Med Chem, 1977 Sep, 20(9), 1213 - 5
Inhibitors of folate biosynthesis . 1 . Inhibition of dihydroneopterin aldolase by pteridine derivatives; Zimmerman M et al.; 2-Amino-6-carboxamido-7,8-dihydropteridin-4-one and 2-amino-6-hydroxymethyl-7,7-dimethyl-7,8-dihydropteridin-4-one have been shown to be good inhibitors of Escherichia coli dihydroneopterin aldolase, an early enzyme of de novo folate biosynthesis.

Am J Vet Res, 1977 Sep, 38(9), 1323 - 6
Resistance of neonatal calves given colostrum diet to oral challenge with a septicemia-producing Escherichia coli; Johnston NE et al.; Twenty Holstein-Friesian male calves were obtained within 4 hours after bith (colostrum deprived) and allotted to 1 of 4 groups, each given a different feeding: colostrum, milk replacer, polyvinylpyrrolidone (PVP), and saline solution (0.85% NaCl) . Each calf was fed 2 L of the respective diets every 12 hours . Rectal temperatures were recorded and blood samples were collected immediately before each feeding . At approximately 27 hours of age, all calves were inoculated orally with 1.5 X 10(10) viable organisms of a septicemia-producing Escherichia coli serotype O26: K60:NM . Within 8 hours, all calves had diarrhea . Coli-septicemia (E coli cultured from liver, spleen, and cardiac blood) was present in 1 of the 5 calves fed colostrum, in 5 or the 5 calves fed milk replacer, in 5 of the 5 calves fed PVP, and in 4 of the 5 calves fed saline solution . At necropsy of the calves (12 to 48 hours after oral inoculation), the same organism was isolated by cultural technique from small intestines of 19 of the 20 calves . Serum immunoglobulin G concentrations increased (P less than 0.01) in calves fed the colostrum diet in sharp contrast to the agammaglobulinemia occurring in calves fed the milk replacer, PVP, or saline solution . Results indicate that colostrum fed to the calf soon after birth provides protection from colisepticemia, but does not prevent the diarrhea of colibacillosis.

Am J Vet Res, 1977 Sep, 38(9), 1307 - 14
Absorption of horseradish peroxidase by neonatal pig intestinal epithelium: effect of Escherichia coli (055B5) on absorption; Staley TE; The pathway of macromolecular transport through the neonatal pig small intestinal epithelium was examined, utilizing the cytochemical marker horseradish peroxidase (HRP) . The marker was found adsorbed to the apical microvillous of the enterocytes, within apical tubules, and cytoplasmic vacuoles . Extracellular absorbed marker assumed a spherical appearance within the subepithelial spaces but was dispersed within the capillary lumens . Uptake of HRP into the enterocyte occurred in 48-hour old neonatal pigs, but transport into the circulation was not observed . Adherence of Escherichia coli to the surface of the ileal enterocyte did not totally inhibit HRP uptake . The E coli adhered to the surface of the enterocyte or within intercellular vacuoles appeared to be static in as much as they were not involved in the transepithelial migration of envacuolated HRP.

Genetics, 1977 Sep, 87(1), 1 - 18
Analysis of the role of recombination and repair in mutagenesis of Escherichia coli by UV irradiation; Kato T et al.; Multiple mutant strains have been tested or their mimicry of the UV-mutagenesis deficiency of a recA single mutant . Revertants to histidine prototrophy and clear plaque mutants of lambda were scored to determine capacity for UV-mutagenesis . Nearly normal capacity was shown by a uvr+ recB- recF- strain, which shows almost no recA-dependent recombination, by uvr- recB+ recF- strains, which show almost no recA-dependent repair and by a uvrA- recB- recF- strain, which shows neither recA-dependent recombination nor repair . Since the uvr mutants can be assumed to show additionally no excision repair, these results may mean that UV-mutagenesis occurs during processes other than recombination and repair . Alternative hypotheses are discussed . The slight difference in mutagenic capacity was traced to the recF single mutation, which blocks the production of unmixed bursts of clear-plaque lambda mutants . Since this accounts for only about 10% of the mutations leading to clear-plaque mutants, it is suggested that there is more than one UV-mutagenic process.

Eur J Biochem, 1977 Sep, 78(2), 557 - 67
Membrane proteins of Escherichia coli K-12: two-dimensional polyacrylamide gel electrophoresis of inner and outer membranes; Sato T et al.; Protein compositions of the inner and outer membranes of Escherichia coli K-12 have been analyzed by two-dimensional gel electrophoresis in which proteins are separated according to apparent isoelectric point (first dimension) and to apparent molecular weight (second dimension) . Membrane proteins except for a pair of major outer membrane proteins (proteins Ia and Ib) were found to be solubilized effectively by lysis buffer containing urea, Triton X-100, ampholines and 2-mercaptoethanol . The latter two proteins could be solubilized after precipitation of membrane fraction with trichloroacetic acid; they formed a pair of spots at an acidic region on the electropherogram . Another major protein of the outer membrane, protein II, was also identified . Most of the inner and outer membrane proteins were shown to be focused at a pH range between 4 and 6.5 . Specific protein patterns characteristic for both the inner and outer membranes could thous be visualized by the present system . At least 120 and 50 protein species were detected for the inner and outer membranes, respectively.

Eur J Biochem, 1977 Sep, 78(2), 403 - 9
Ternary complex formation between elongation factor Tu, GTP and aminoacyl-tRNA: an equilibrium study; Pingoud A et al.; The equilibria between the elongation factor Tu-GTP complex (EF-Tu-GTP) from Escherichia coli and tyrosyl-tRNATyr from E . coli as well as phenylalanyl-tRNAPhe and seryl-tRNASer from yeast were studied using a novel procedure, which takes advantage of the protective effect of ternary complex formation on the stability of theaminoacyl bond against non-enzymatic hydrolysis . At 25 degrees C and at pH 7.4 tyrosyl-tRNATyr, phenylalanyl-tRNAPhe and seryl-tRNASer are bound with binding constants of 0.7 X 10(7) M-1, 5.0 X 10(7) M-1 and 0.5 X 10(7) M-1 respectively . The binding of aminoacyl-tRNA to EF-Tu-GTP has a negative deltaH of the order of 10 kcal/mol (42 kJ/mol) . Complex formation is dependent on ionic strength: with 0.1 M KCl Kass = 0.8 X 10(7) M-1, with 0.5 M KCl Kass = 0.2 X 10(7) M-1 was determined for the binding of Tyr-tRNATyr.

Eur J Biochem, 1977 Sep, 78(2), 333 - 6
Affinity chromatography on agarose-hexyl-adenosine-5'-phosphate of methionyl-tRNA synthetase from Escherichia coli . Application of the couplings between the methionine and ATP sites; Fayat G et al.; Recent studies by us {Biochemistry (1977) 16, 2570-2579} have shown that L-methioninol, a methionine analog lacking the carboxylate negative charge, enhances the affinity of AMP for methionyl-tRNA synthetase while L-methionine antagonizes the nucleotide binding . Such couplings between ligands of the enzyme have now been applied to affinity chromatography of methionyl-tRNA synthetase on an agarose-hexyl-adenosine-5'-phosphate gel (the spacer is attached to AMP at the adenine C-8 position) . Retention of the enzyme on this gel column was shown to be dependent on the presence of appropriate concentrations of magnesium and of L-methioninol in the equilibration buffer . The enzyme was then specifically recovered from the column by omitting the amino alcohol or by adding an excess of L-methionine which antagonizes the cooperative effect of L-methioninol . This approach has provided the basis for a new purification procedure of methionyl-tRNA synthetase which leads to a 200-fold purification in a single chromatographic step . In this manner, after 30-50% ammonium sulfate fractionation of extracts of Escherichia coli EM 20031 (carrying the F32 episome), 0.25 mg X methionyl-tRNA synthetase was obtained at 90% purity per ml of agarose-hexyl-adenosine-5'-phosphate gel.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3970 - 4
Specialized transducing phage for the initiation factor 3 gene in Escherichia coli; Springer M et al.; A previously isolated thermosensitive mutant {Springer, M., Graffe, M . & Grunberg-Manago, M . (6977) Mol . Gen . Genet . 151, 17-26} exhibits two defects in vitro, one in the initiation factor IF3 and the other in the L-phenylalanine: tRNA-Phe ligase (EC 6.1.1.20) . Specialized lambda transducing phages that transduced this mutant to thermoresistance were selected . In vitro studies showed that the transductants had a normal IF3 activity . One of these transducing phages was shown to code for a protein synthesized under the control of Escherichia coli promoters, which has the same molecular weight as IF3 . This protein crossreacts specifically with IF3 antisera and comigrates with pure IF3 in a two-dimensional gel system.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3965 - 9
Excision of F plasmid sequences by recombination at directly repeated insertion sequence 2 elements: involvement of recA; Deonier RC et al.; The DNA of the F plasmid is joined to bacterial DNA sequences in the F' ORF203 by directly repeated insertion sequence 2 (IS2) elements . The rate of excision of the F plasmid form this F' (presumably by recombination at the directly repeated IS2s) has been estimated in both recA+ and recA- strains . Normal F is produced in the recA+ strain, but is not detected in recA- . The autonomous plasmids produced in the recA- background were F's having deletions . F excision in this particular recA+ case is specific in the sense that the directly repeated IS2s appear to be more active in recombination than similarly disposed IS3 direct repetitions in this F'.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3932 - 6
Involvement of DNA-dependent RNA polymerase in a recA-independent pathway of genetic recombination in Escheria coli; Ikeda H et al.; Recombinant DNA molecule of phage lambda formed in Escherichia coli in the presence of chloramphenicol and/or rifampin can be assayed by their biological activity . recA- cells were found to be capable of forming recombinant lambda phage DNA in the presence of chloramphenicol . The relatively high recA-independent recombination observed in this system contrasts with the relatively low recA-independent recombination when recombinant phage particles rather than recombinant DNA are titrated . Formation of the recombinant DNA was suppressed by the the addition of rifampin . The introduction of the rif-r mutation into host bacteria made their recombination activity rifampin-resistant . These results show that DNA-dependent RNA polymerase (EC 2.7.7.6) is involved in this recA-independent pathway of recombination, which is named the "Rpo pathway." This is distinct from Red, Int, RecBC, RecE, or Der pathways of recombination . Crossover was much more frequent in the N-PL-cI and cI-PR-O regions than in the A-D and O-S regions . The crossover seems to occur in the regions that are transcribed actively . Some local change of DNA structure caused by transcription might be required for the Rpo pathway of recombination.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3642 - 6
Filamentous coliphage M13 as a cloning vehicle: insertion of a HindII fragment of the lac regulatory region in M13 replicative form in vitro; Messing J et al.; A HindII restriction fragment comprising the Escherichia coli lac regulatory region and the genetic information for the alpha peptide of beta-galactosidase (beta-D-galactosidegalactohydrolase, EC . 3.2.1.23) has been inserted into 1 of the 10 Bsu I cleavage sites of M13 by blunt end ligation . A stable hybrid phage was isolated and identified by its ability to complement the lac alpha function . Further characterization of the hybrid phage includes retransformation studies, agarose gel electrophoresis, DNA-DNA hybridization, and heteroduplex mapping . The insertion point has been localized at 0.083 map unit on thewild-type circular map-i.e., within the intergenic region . The results prove that part of the intergenic region is nonessential and that the phage can be used as a cloning vehicle.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3497 - 50
Mutator action by Escherichia coli strains carrying dnaE mutations; Sevastopoulos CG et al.; Several newly isolated temperature-sensitive dnaE mutants of Escherichia coli exhibit powerful mutagenic action at permissive temperatures . Mutation rates for the two most active mutants were assayed at four different temperatures and compared to wild-type behavior . Temperature-resistant revertants of the original temperature-sensitive dnaE mutants exhibited lower, nearly normal, mutation rates, but no antimutator strains were found.

Nucleic Acids Res, 1977 Sep, 4(9), 3039 - 54
Studies on gene control regions . VI . The 5- methyl of thymine, a lac repressor recognition site; Goeddel DV et al.; Three site specific deoxyuridine analogs of lac operator were tested for binding with wild type (SQ) and tight binding (QX86) lac repressors . Insertion of uracil for thymine at site 13 (our nomenclature) significantly reduced the dissociation half-life of QX86 repressor for lac operator DNA (21 vs 1.2 min) . Two other sites (6 and 7) are affected to a much lesser extent.

Biosystems, 1977 Sep, 9(2-3), 151 - 4
Evolutionary significance of the system utilizing D-amino acid enantiomers; Aono H et al.; The evolutionary significance of the system utilizing D-amino acid enantiomers in living organisms is discussed, based on an experiment in which the mutant from Escherichia coli K--12 4627 grown on D-tryptophan was used . The mutant shows the ability of D-tryptophan is degraded to indol which can be utilized for the synthesis of L-tryptophan in the presence of serine.

Acta Paediatr Scand, 1977 Sep, 66(5), 549 - 52
Cellular and humoral factors involvement in the enhanced NBT reduction by neutrophil leucocytes of newborn infants; Tovo PA et al.; The histochemical NBT test was performed on blood samples from ten healthy newborn infants . High spontaneous NBT reduction has been confirmed for neutrophils and assessed for monocytes . The stimulation of both neutrophils and monocytes with Escherichia coli endotoxin induces a statistically significant increase of NBT positive cells . The reason for the false positive test results in neonates was investigated by incubating neutrophils from adult donors and for different time periods in either neonatal or adult plasma before the addition of NBT . NBT reduction by adult neutrophils was increased after incubation in neonatal plasma, and this increase was related to the concentration of the plasma used . Maximum NBT reduction was observed after 90 min of incubation, at which time the NBT scores of adult cells incubated in neonatal plasma were similar to the results of tests performed on whole neonatal blood . It is concluded that neonatal leucocytes demonstrate efficient spontaneous and stimulated phagocytosis, and that there are, in the plasma of neonates, humoral factors which stimulated phagocytosis by neutrophils and are thus responsible for the false positive NBT test results observed in these subjects.

J Bacteriol, 1977 Sep, 131(3), 970 - 80
Heteroduplex analysis of tra delta f' plasmids and the mechanism of their formation; Guyer MS et al.; Four tra delta FargG+ plasmids, derived from matings between Hfr AB312 and a recA recipient, have been shown to have deletions of at least 50% of the F genome, including the region in which the tra genes map . The mutant plasmids do contain the F genes required for plasmid maintenance . Correlations can be made between, on the one hand, the F genes present on the tradelta F' plasmids and the F genes transferred early by an Hfr donor, and, on the other hand, the F genes deleted from the tradelta F' plasmids and the F genes transferred late by an Hfr donor . A biased representation of proximally and distally transferred chromosomal markers among the tradelta F' elements was also demonstrated . Taken Taken together, the asymmetrical representation of Hfr genes and the cis dominance of the Tra phenotype of these mutants can best be explained by the hypothesis that the tradelta F' plasmids are formed by repliconation of the transferred exogenote in a recA recipient.

J Bacteriol, 1977 Sep, 131(3), 929 - 42
Origin and direction of replication of the drug resistance plasmid R100.1 and of a resistance transfer factor derivative in synchronized cultures; Silver L et al.; The origin and direction of replication of the resistance plasmid R100.1 and its resistance transfer factor derivative, pAR132, were studied by electron microscopy autoradiography of partially denatured molecules and partial denaturation mapping of replicative intermediates . Results of these studies indicate the existence of an origin of replication at 8.8 kilobases on the R100 map . Replication from this origin in cultures synchronized for initiation of replication is predominantly unidirectional in a single direction.

J Bacteriol, 1977 Sep, 131(3), 848 - 53
Glutamate transport driven by an electrochemical gradient of sodium ions in Escherichia coli; Tsuchiya T et al.; The role of Na+ in glutamate transport was studied in Escherichia coli B, strain 29-78, which possesses a very high activity of glutamate transport (L . Frank and I . Hopkins, J . Bacteriol., 1969) . Energy-depleted cells were exposed to radioactive glutamate in the presence of a sodium gradient, a membrane potential, or both . One hundred- to 200-fold accumulation of the amino acid was attained in the presence of both electrical and chemical driving forces for the sodium ion . Somewhat lower accumulation values were obtained when either chemical or electrical driving forces were applied separately . A chemical driving force was produced by the addition of external Na+ to Na+-free cells . A membrane potential was established by a diffusion potential either of H+ in the presence of carbonyl cyanide p-trifluoromethoxyphenylhydrazone or of SCN- . These results support the hypothesis of a Na+-glutamate cotransport . Na+-driven glutamate transport was also observed in wild-type E . coli B but not in a strain of K-12.

J Bacteriol, 1977 Sep, 131(3), 830 - 8
Isolation, genetic analysis, and characterization of Escherichia coli mutants with defects in the lacY gene; Hobson AC et al.; Five hundred thirty-five lacY mutants were isolated from an Escherichia coli strain carrying the lactose operon on an F' factor, either without mutagenesis or after mutagenesis with 2-aminopurine or N-methyl-N'-nitro-N-nitrosoguanidine . Crosses against 48 independently isolated deletions ending in the lacY gene divided the gene into 36 deletion groups . Suppressibility studies with 7 nonsense suppressor strains classified 276 mutants as nonsense mutants and 78 as missense (or nonsuppressible) mutants . One hundred seventy-nine mutants were "leaky" and could not be so allocated, and two were found to have small internal deletions . Nonsense mutants could in many cases be subdivided even within deletion groups on the basis of their suppressibility pattern, giving a total of 70 groups of nonsense mutants . Studies of these mutants allow the following conclusions: lactose and melibiose most probably do not have separate binding sites on the permease; the lacY region most likely consists of one cistron, and so both active transport and facilitated diffusion are functions of one protein; and finally, there is probably no small defined region of the permease responsible for energy coupling of transport . Furthermore, the strains and the analysis form the basis for a future functional study of the permease by biochemical techniques.

J Bacteriol, 1977 Sep, 131(3), 815 - 20
Intracellular localization of the superoxide dismutases of Escherichia coli: a reevaluation; Britton L et al.; All of the superoxide dismutase isozymes of Escherichia coli have been shown to occur in the cell matrix, and none have been found in the periplasm . This was the case with both E . coli B and E . coli K-12, whether grown on a low phosphate medium or on a Trypticase soy-yeast extract medium . Alkaline phosphatase was used as a marker of the periplasm; adenosine deaminase and glucose 6-phosphate dehydrogenase were used as matrix markers, and consistent results were obtained by osmotic shock, spheroplast formation, and use of a diazonium salt that penetrates the periplasm but cannot cross the plasma membrane . A previous report that the iron-containing superoxide dismutase of E . coli is a periplasmic enzyme is now seen to have been in error.

J Bacteriol, 1977 Sep, 131(3), 801 - 8
Genetic analysis of Escherichia coli K-12 region I flagellar mutants; Komeda Y et al.; Flagellar mutants in Escherichia coli region I were obtained by selection for resistance to the flagellotropic phage chi . F' elements carrying this region of the E . coli genome were then constructed . Stable merodiploid strains with a flagellar defect on the exogenate and another on the endogenote were prepared . These merodiploids yielded information on the complementation behavior of mutations in this region . Region I was shown to include at least six cistrons, flaV, flaK, flaL, flaM, flaS, and flaT . Mu-induced and deletion fla mutants were also isolated . By using these mutant strains, the transcriptional order was shown to be flaV-flaK-flaL-flaM-flaS-flaT . The definition of region I fla genes and their transcriptional relationships were confirmed by genetic tests with hybrid A phage carrying fla genes in this region.

J Bacteriol, 1977 Sep, 131(3), 759 - 64
Genetic characterization of an Escherichia coli mutant altered in the structure of murein lipoprotein; Yem DW et al.; Mutants defective in the structure, biosynthesis, and assembly of murein lipoprotein have been isolated . One of these mutants has been shown to synthesize a structurally altered lipoprotein . The biochemical features of the mutant lipoprotein (lipid deficiency, dimer formation, and a reduced, bound form of lipoprotein) could be attributed to a single mutation (or closely linked mutations) located at 36.4 min of the Escherichia coli map . We propose that this mutant is altered in the structural gene for murein lipoprotein (mlpA) . Biochemical studies carried out with a heterogenote, mlpA/F'mlpA+, revealed the biochemical codominance of the wild-type and mutant genes.

J Bacteriol, 1977 Sep, 131(3), 1033 - 6
Fine-structure mapping of the firA gene, a locus involved in the phenotypic expression of rifampin resistance in Escherichia; Lathe R; The firA (Ts)200 mutation not only eliminates the resistance to rifampin of certain genetically resistant strains, but, moreover, renders ribonucleic acid synthesis thermolabile . The firA gene has been mapped by P1 tranduction and is located extremely close to the structural gene for deoxyribonucleic acid polymerase III at 4 min on the Escherichia coli linkage map.

J Bacteriol, 1977 Sep, 131(3), 1023 - 5
Propionate-induced synthesis of odd-chain-length fatty acids by Escherichia coli; Ingram LO et al.; Exogenous propionate is incorporated in vivo by Escherichia coli as a primer to produce lipids with fatty acids of odd chain lengths . This provides a method for the specific labeling of the three terminal carbons in the fatty acyl chains of phospholipids.

Surg Gynecol Obstet, 1977 Sep, 145(3), 401 - 7
Systemic vascular performance in endotoxic shock; Seyfer AE et al.; Sixteen dogs were studied in an effort to investigate certain peripheral vascular and metabolic parameters in endotoxic shock . Cardiopulmonary bypass was instituted for 12 of the dogs to study systemic parameters at constant circulatory flow rates . From these studies, it appears that endotoxin is capable of initiating profound hemodynamic and metabolic changes . Initially, cardiac output and arterial pressure drop precipitiously, despite a transient rise in systemic and pulmonary vascular resistance . Subsequently, peripheral arterial pressures and systemic vascular resistance continue to decline, even if arterial flow remains at constant levels . Oxygen extraction by peripheral tissues decreases after endotoxin injection, despite adequate oxygen availability and constant hemoglobin levels.

Proc Natl Acad Sci U S A, 1977 Sep, 74(9), 3696 - 700
Role of ribothymidine in mammalian tRNAPhe; Roe BA et al.; We have previously reported that mammalian tRNAsPhe from variation tissues contain different amounts of ribothymidine and that a uridine methylase from Escherichia coli can quantitatively convert these tRNAs to species that contain their full complement ofribothymidine at position 23 from the 3' terminus . The role of ribothymidine in mammalian tRNAs has now been investigated by studying the ability of several highly purified mammalian tRNAsPhe, differing only in their ribothymidine content, to support poly(U)-directed poly(Phe) synthesis under various conditions . Our results indicate that the ribothymidine content of mammalian tRNAPhe can be correlated with the ability of these tRNAs to functionin vitro in a low-magnesium (6 mM), ribosome wash factor-dependent, poly(U)-directed poly(Phe) synthesis system from rat liver . Specifically, the effect of increasing the ribothymidine content in a class C mammalian tRNA becomes manifest in an increased apparent maximum velocity for the overall synthesis of poly(Phe), while the apparent Michaelis constant (Km) remains essentially unchanged . It is postulated that the modifiednucleoside ribothymidine might be involved in the regulation of protein synthesis at the level of translation in mammalian liver.

J Biochem (Tokyo), 1977 Sep, 82(3), 835 - 7
Inhibition by Mg2+ of the interaction of Ca2+ with spin-labeled g2 bound to myosin; Okamoto Y et al.; According to the measurement of ESR spectrum, Ca2+ induced conformational change of spin-labeled g2 bound to myosin in the presence of 1 mM Mg2+ . The half-maximal changes were observed at pCa 6.8 and at pCa 3.7 . Spin-labeled phosphorylated g2 bound to myosin showed one transition at pCa 4.5, which shifted to pCa 6.5 after the dephosphorylation with E . coli alkaliphosphatase.

J Bacteriol, 1977 Sep, 131(3), 1026 - 8
Kinase replacement by a dehydrogenase for Escherichia coli glycerol utilization; St Martin EJ et al.; A mutant of Escherichia coli that employs a glycerol:nicotinamide adenine dinucleotide 2-oxidoreductase (EC 1.1.1.6), instead of adenosine 5'-triphosphate:glycerol 3-phosphotransferase (EC 2.7.1.30), as the first enzyme for the dissimilation of glycerol was constructed . This mutant, like the wild-type strain, still cannot grow anaerobically on glycerol without an exogenous hydrogen acceptor.

J Virol, 1977 Sep, 23(3), 659 - 68
Extensive in vitro transcription of rous sarcoma virus RNA by avian myeloblastosis virus DNA polymerase and concurrent activation of the associated RNase H; Darlix JL et al.; Conditions are described that promote the efficient reverse transcription of most of Rous sarcoma virus (RSV) RNA sequences by avian myeloblastosis virus DNA polymerase in vitro . A detailed analysis of the reverse transcription reaction was carried out using two procedures: in situ analysis of the RNA sequences transcribed and DNA-RNA annealing studies . Under optimal conditions, after 1 h of reaction, practically all RSV RNA sequences were transcribed with a frequency varying from 30 to 90% . The DNA product was at least 95% single stranded, had a chain length ranging from a few hundred up to 5,000 necleotide residues, half of it being larger than 1,000 residues, and, after hybridization at RNA excess, protected the entire RSV genome from RNase digestion, as monitored by the large T1 oligonucleotides of RSV RNA . Analysis of the product of a very short reaction time (5 min) showed that DNA synthesis occurs mainly at three sites, one near the 5' end and two near the center of the subunit RNA . This in in agreement with our previous analysis of a much less efficient reverse transcription reaction . Under optimal conditions of reverse transcription, we find now that the RNase H associated with the avian myeloblastosis virus DNA polymerase is active in degrading the RNA moiety of the RNA-DNA hybrids synthesized.

Acta Virol, 1977 Sep, 21(5), 359 - 64
Physico-chemical properties of interferon produced by a mixed leukocyte suspension; Taborsky I et al.; Physico-chemical properties of partially purified interferon produced by a mixed culture of human peripheral blood leukocytes following induction with double-stranded RNA extracted from f2 phage infected Escherichia coli were studied . Molecular heterogeneity of the interferon preparation was demonstrated by gel chromatography on a Sephadex G-100 column, disc electrophoresis in polyacrylamide gel and by sodium dodecyl sulphate-polyacrylamide gel electrophoresis . The first two methods revealed 5 peaks, the latter 7 peaks of interferon activity . There was no difference in the molecular nature of interferon produced by cultures exposed to the inducer for the whole period of incubation and that produced by cultures from which the inducer was removed after a short induction time.

Infect Immun, 1977 Sep, 17(3), 629 - 33
Repression of heat-stable enterotoxin synthesis in enterotoxigenic Escherichia coli; Alderete JF et al.; Five different carbon sources were examined for their ability to control synthesis of heat-stable enterotoxin (ST) by enterotoxigenic (ENT+) Escherichia coli grown in either a defined medium containing four amino acids or a minimal salts medium . No ST activity was observed when D-glucose, D-gluconate, and L-arabinose were added separately to the defined medium, whereas glycerol and pyruvate decreased toxin levels . Similar results were obtained using a minimal salts medium, except with pyruvate, which did not support growth . Inhibition of ST synthesis by D-glucose was overcome by the addition of 3 X 10(-3) M cyclic adenosine 3',5'-monophosphate . Glucose repression of beta-galactosidase synthesis under conditions optimal for inhibition of ST synthesis was also reversed by exogenous cyclic adenosine 3',5'-monophosphate in the presence of the inducer isopropyl-beta-D-thiogalactopyranoside . The data suggest that control mechanisms for the synthesis of plasmid gene products of bacterial pathogens are similar to those exerted on the host chromosome.

J Bacteriol, 1977 Sep, 131(3), 854 - 65
Cyclic adenosine 3',5'-monophosphate regulation of membrane energetics in Escherichia coli; Dills SE et al.; Mutants of Escherichia coli K-12 lacking functional adenylate cyclase (cya) or the cyclic adenosine 3',5'-monophosphate (cAMP) receptor protein (crp) were compared with their wild type to evaluate the role played by the cAMP-cAMP receptor protein complex in regulating this organism's membrane-associated bioenergetic functions . Both mutants were found to be equally defective in carrying out various electron transport activities . In particular, their capacity for synthesizing a functional oxygen-linked transhydrogenase system was totally repressed, and their content of flavin adenine dinucleotide was reduced by approximately 85% . In addition, it was found that the mutant strains had a decreased ability to generate a protonmotive force and to use this chemiosmotic force to generate adenosine 5'-triphosphate . All these membrane-associated dysfunctions were completely restored to the wild-type state when the cya cells were grown in the presence of exogenous cAMP . As would be expected if these controls were operating at the transcriptional level, the crp cells retained the mutant character even when grown in the presence of this cyclic nucleotide.

J Bacteriol, 1977 Sep, 131(3), 789 - 94
Metabolism of 6-aminonicotinic acid in Escherichia coli; Cobb JR et al.; A late-log-phase culture of an Escherichia coli nadB pncA double mutant took up 6-{7-14C}aminonicotinic acid and excreted 6-{14C}aminonicotinamide . This mutant also accumulated intracellularly several radioactive compounds which have been tentatively identified as 6-amino analogs of compounds in the pyridine nucleotide cycle . It is concluded that 6-aminonicotinamide and 6-aminonicotinic acid probably exert at least a portion of their bacteriostatic effects by being metabolized, by the enzymes of the pyridine nucleotide cycle, to 6-aminonicotinamide adenine dinucleotide and 6-aminonicotinamide adenine dinucleotide phosphate . These compounds are not electron acceptors and are known inhibitors of some pyridine nucleotide-linked dehydrogenases.

J Biol Chem, 1977 Aug 25, 252(16), 5916 - 23
Base-unpaired regions in supercoiled replicative form DNA of coliphage M13; Dasgupta S et al.; Superhelical covalently closed circular replicative form DNA (RF I) of coliphage M13 appears as a relaxed molecule that has a base-unpaired region in the form of a bubble (100 to 200 base pairs long) seen in electron micrographs when spread in the presence of formaldehyde and formamide or after pretreatment with glyoxal . S1 endonuclease, specific for single-stranded DNA, converts superhelical M13 RF I DNA, but not nonsuperhelical M13 RF I to a significant extent, into unit-length linear molecules by sequential nicking of two strands . The locations of S1 nuclease-susceptible sites and glyoxal-fixed base-unpaired regions were both related to the five A-T-rich regions in M13 RF DNA . While S1 nuclease does not show preference for any of these sites, glyoxal-fixed bubbles occur predominantly at the major A-T-rich region in M13 RF DNA.

J Biol Chem, 1977 Aug 25, 252(16), 5615 - 8
Synthesis of RNA from cellulose-bound complementary DNA; Thrash CR et al.; Radioactively labeled RNAs were synthesized from cellulose-bound cDNA templates using Escherichia coli RNA polymerase . Hybridization of this RNA to excess unlabeled cDNA approached 100%, indicating the complementarity of product and template . The average length of the RNA product, as determined by formamide gels, was approximately 40% of the template length . Hybridization of unlabeled globin RNA produced by this technique to labeled globin cDNA indicated the population of RNA sequences represented at least 80% of the template sequences . Approximately 30% of the RNA product by mass contains poly(A) tails as determined by binding to oligo(dT)-cellulose . The template can be reused for several cycles of synthesis with little loss of synthetic capability and therefore, can amplify the amount of mRNA initially used to produce the template.

J Biol Chem, 1977 Aug 25, 252(16), 5750 - 5
Partial purification of 6-(D-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydropterin triphosphate synthetase from chicken liver; Fukushima K et al.; An enzyme that catalyzes the formation of 6-(D-erythro-1',2',3'-trihydroxypropyl)-7,8-dihydropterin triphosphate (D-erythrodihydroneopterin triphosphate) and formic acid from GTP has been purified about 3700-fold from homogenates of chicken liver . The molecular weight of the enzyme, D-erythrodihydroneopterin triphosphate synthetase (GTP cyclohydrolase), has been estimated to be 125,000 by gel filtration on Ultrogel AcA-34 . The enzyme functions optimally between pH 8.0 and 9.2 and is considerably heat-stable . No cofactors or metal ions have been demonstrated to be required for activity; however, the reaction is strongly inhibited by Cu2+ and Hg2+ . GTP is the most efficient substrate, with GDP being 1/17 as active and guanosine, GMP, and ATP being inactive . The Km for GTP has been found to be 14 micrometer . Although the overall reaction catalyzed by D-erythrodihydroneopterin triphosphate synthetase from chicken liver is identical with that from Escherichia coli GTP cyclohydrolase, immunological studies show no apparent homology between the two enzymes.

Biochim Biophys Acta, 1977 Aug 23, 493(2), 367 - 79
Modification of tyrosine residues of the lactose repressor protein; Alexander ME et al.; Reaction of the lactose repressor protein from Escherichia coli with high molar excesses (up to 800 fold) of tetranitromethane resulted in modification of tyrosine residues in the amino-terminal and core regions of the molecule . Tyrosines 7 and 17 exhibit significant reactivity at low levels (5-10 fold molar excess) of tetranitromethane . The loss of operator binding activity upon nitration at these low concentrations of reagent indicates involvement of these two tyrosines in the binding process . Inducer binding activity was maintained at approx . 90% of unreacted repressor for all excesses of reagent studied . Addition of inducer to the repressor prior to reaction resulted in decreased modification of tyrosines in the core region, but anti-inducers did not affect the reaction significantly . The effect of inducers on the pattern of reaction apparently reflects the conformational change which occurs upon binding of these ligands . Acetylation of the repressor protein with N-acetylimidazole modified lysines and tyrosines with complete loss of operator binding activity and retention of 75-80% of inducer binding activity.

Biochim Biophys Acta, 1977 Aug 16, 477(4), 323 - 33
Translation in Escherichia coli mini-cells containing hamster mitochondrial DNA-Co1E1 - Ampr recombinant plasmids; Miller DL et al.; Hamster mitochondrial DNA is cleaved into two fragments (4.2 and 11.4 kilobase pairs of DNA (kb)) by the restriction enzyme, Eco RI . Recombinant DNA molecules formed in vitro between an Escherichia coli plasmid, Co1E1 - Ampr, and Eco RI-digested hamster mitochondrial DNA were transformed into E . coli K12 . The translation products of the parent plasmid, Co1E1 - Ampr, and recombinant plasmid DNAs containing (i) the 4.2 kb mitochondrial DNA fragment and (ii) the 11.4 kb fragment were characterized on sodium dodecyl sulfate-polyacrylamide gels using bacterial mini-cell lysates . The Co1E1 - Ampr plasmid specifies at least six polypeptides whose structural genes comprise 56% of the plasmid DNA . Insertion of hamster mitochondrial DNA at the Eco RI site of the plasmid alters the relative rate of synthesis of these six polypeptides and induces the occurrence of a new band on sodium dodecyl sulfate-polyacrylamide gels which is probably not specified by the inserted mitochondrial DNA sequences.

Biochim Biophys Acta, 1977 Aug 16, 477(4), 371 - 8
Reversal of ultraviolet-killing in an Escherichia coli lon mutant . Differential effects of protein synthesis inhibitors; Kato Y et al.; The effects of protein synthesis inhibition in post-irradiation treatments on the ultraviolet-survival of an Escherichia coli lon mutant were examined with six antibiotics . Kasugamycin was the most potent in enhancing the ultraviolet survival, whereas puromycin promoted ultraviolet killing rather than survival . Rifampicin, chloramphenicol, chlortetracycline, and spectinomycin were weakly active in the enhancement of survival.

Eur J Biochem, 1977 Aug 15, 78(1), 141 - 51
Isolation and characterization of two methionine: tRNA ligases from wheat germ; Rosa MD et al.; Two methionine: tRNA ligases (here called ligase A and ligase B) with distinctly different enzymatic and molecular properties were isolated in homogenous form from extracts of raw wheat germ . Both the A and B enzyme are composed of single polypeptide chains of Mr 105000 and 70000 respectively . The smaller molecule (B) has been shown not to be a proteolytic fragment of the larger one (A) . The catalytic properties of both the A and B enzymes have been established and the Mg2-dependent capacity to charge six purified methionine-accepting tRNAs have been compared to those of the methionine: tRNA ligases from Escherichia coli and bakers' yeast . The possible reasons for the presence of two methionine: tRNA ligases and their unusual monomeric nature are discussed.

Eur J Biochem, 1977 Aug 15, 78(1), 1 - 10
Repetitive and non-repetitive sequences in the transcript in vitro of porcine thyroid chromatin; Avvedimento VE et al.; Purified pig thyroid chromatin has been transcribed in vitro with Escherichia coli RNA polymerase . The transcript, analyzed by DNA-RNA hybridization, shows two major kinetic components: 40% of the transcript is copied by repetitive sequences present 100 times per haploid genome; another 25% anneals to DNA with a rate constant Kh 10-4 M - S-1, typical of single-copy sequences . The transcript annealed at cot = 40 M - S to fractions of 2000-nucleotide DNA, when banded in neutral CsCl gradient only hybridizes to the heavy side of the main band . At cot = 3000 M - S, another hybridizing fraction appears on the light side of the main band of the gradient . The reassociation properties of these fractions show that the heavy DNA fraction is reiterated about 100 times per haploid genome, whereas the light DNA appears as a unique sequence, associated to small repetitive elements . The transcript, analyzed by formamide/sucrose gradient, shows two peaks with sedimentation coefficients of 10 S and 4 S, respectively . The 10-S RNA, hybridized to native 2000-nucleotide-length DNA, has a Kh of 10-4 M - S-1 and a cot1/2 of 10(3) M - S, typical of single-copy sequences.

Eur J Biochem, 1977 Aug 15, 78(1), 55 - 61
Specificity of elongation factor Tu from Escherichia coli with respect to attachment to the amino acid to the 2' or 3'-hydroxyl group of the terminal adenosine of tRNA; Sprinzl M et al.; Modified Tyr-tRNATyr and Phe-tRNAPhe species from yeast having the aminoacyl residue bound specifically to the 2' and 3' position of the terminal adenosine, respectively, were investigated for their ability to form ternary complexes with Escherichia coli elongation factor Tu and GTP . Both Tyr-tRNATyr-CpCpA (2'd) and Tyr-tRNATyr-CpCpA(3' d) derivatives which are esterified with the amino acid on the 3' and 2' position respectively and which lack the vicinal hydroxyl were able to form ternary complexes . The stability of these ternary complexes was lower than in the case of native Tyr-tRNATyr-CpCpA . Tyr-tRNATyr-CpCpA(3' d) having the amino acid attached to the 2' position interacted considerably more strongly with EF-Tu - GTP than Tyr-tRNATyr-CpCpA(2' d) . Ternary complex formation was observed with neither Phe-tRNAPhe-CpCpA(2'NH2) nor Phe-tRNAPhe-CpCpA(3'NH2) . It is concluded that 2' as well as 3' isomers of native aminoacyl-tRNA can be utilized for ternary complex formation but in a following step a uniform 2'-aminoacyl-tRNA - EF-Tu - GTP complex is formed . Although the free vicinal hydroxyl group of the terminal adenosine is not absolutely required, replacement of the ester linkage through with the amino acid is attached to tRNA by an amide linkage leads to loss of ability to interact with elongation factor Tu.

Eur J Biochem, 1977 Aug 15, 78(1), 267 - 72
Functional roles of 50-S ribosomal proteins; Hernandez F et al.; Ribosomal proteins previously inactivated by treatment with fluorescein isothiocyanate have been incorporated into 50-S ribosomal subunits during reconstitution from particles disassembled by 2 M LiCl in the presence of an excess of the modified proteins . The reconstituted particles show alterations in some functional activities resulting from the incorporation of the inactive ribosomal proteins added exogenously . Of the fluorescein-isothiocyanate-treated proteins incorporated, L24 and L25 drastically affect all the activities tested and these proteins possibly play a fundamental role in determining the overall structure of the particle . Proteins L16 and L10 are apparently involved both in the GTP hydrolysis dependent on elongation factor G and in peptidyl transferase activity but the modified protein L11 only affects GTPase activity indirectly and interferes with the ribosome assembly process involving proteins L7 and L12 . Protein L1 may be involved with peptidyl transferase activity while proteins L7 and L12, in agreement with many reports in the literature, affect the factor-dependent hydrolysis of GTP.

Eur J Biochem, 1977 Aug 15, 78(1), 239 - 49
Modification of L-isoleucyl-tRNA synthetase with L-isoleucyl-bromomethyl ketone . The effect of the catalytic steps; Rainey P et al.; The rapidly reacting cysteine-sulfhydryl group of L-isoleucyl-tRNA synthetase has been specifically alkylated with L-isoleucyl-bromomethyl ketone {Rainey, P., Holler, E . & Kula, M.-R . (1976) Eur . J . Biochem . 63, 419-426} . We have now investigated the catalytic and substrate binding properties of the modified protein by radioactive and fluorescence techniques . The rate constants for the transfer of AMP and isoleucine from the protein - adenylate complex to form ATP or Ile-tRNAIle were only 3% of those for native enzyme, whereas the rate constant for the formation of adenylate was essentially unchanged . The tendency to form synthetase - substrate complexes remained almost unchanged with the exception of L-isoleucine which exhibited a 20-fold reduction . Similarly, complex formation of L-isoleucinol together with its synergistic coupling to complex formation of ATP was partially inhibited . The results rule out the essential participation of the rapidly alkylatable cysteine-sulfhydryl group during catalysis.

Eur J Biochem, 1977 Aug 15, 78(1), 215 - 20
Electron microscopy analysis of the interaction between Escherichia coli DNA-dependent RNA polymerase and the replicative form of phage fd DNA . 2 . Analysis of the dissociation kinetics; Giacomoni PU et al.; The kinetics of dissociation of the fd DNA - RNA-polymerase complex has been analyzed . Heparin was added to a solution of the enzyme - DNA complex in order to trap free polymerases . At different times after, samples were taken and analyzed by electron microscopy to determine the mean number of enzymes bound per DNA molecule . Unexpectedly, the measured dissociation is not a first-order reaction . The apparent rate constant increases with heparin concentration in the range between 0.001 and 2 mg/ml . These results strongly suggest the existence of a direct transfer process of RNA polymerase to heparin, bypassing the rate-limiting step of dissociation of the enzyme - DNA complex to free enzyme . Theoretical analysis of the direct-transfer model shows that the rate constant of dissociation should level off at high heparin concentrations: measurements of the residual transcription activity show that this is the case . From these experiments, the equilibrium constant of the DNA - RNA-polymerase complex can be determined . The value K = 10(12) M-1 which is obtained solves a striking paradox which existed because measurements performed in other laboratories indicated K = 10(14) M-1, which is greater than the equilibrium constant of the lac-repressor - lac-operator complex (=10(13) M-1).

Eur J Biochem, 1977 Aug 15, 78(1), 205 - 13
Electron microscopy analysis of the interaction between Escherichia coli DNA-dependent RNA polymerase and the replicative form of phage fd DNA . 1 . Mapping of the binding sites; Giacomoni PU et al.; The interaction of Escherichia coli DNA-dependent RNA polymerase (EC 2.7.7.6) with the replicative form of the DNA from the filamentous coliphage fd cleaved by the restriction endonuclease HindII has been studied by electron microscopy at low and high ionic strength . In the presence of ATP or GTP, and heparin, RNA polymerase binds to fd replicative-form DNA at a few specific sites which have been mapped . The map was oriented so that transcription is from right to left . Three main GTP initiator sites are found at 15%, 82% and 94% of the genome length . One main ATP initiator site is found which cannot be mapped with the same accuracy, and which is localized between 38% and 50% . In the absence of initiator triphosphates and heparin, the binding of the enzyme to fd DNA is much more heterogeneous and therefore the mapping is more difficult . Nevertheless it seems that the preferential binding regions correspond to the specific sites mapped in the presence of GTP or ATP . The mean number of polymerase molecules bound to DNA as a function of the molecular ratio enzyme to DNA present in the mixture has been determined . From these results a binding isotherm can be obtained . The apparent equilibrium constant (K approximately 10(9) M-1) which is derived certainly represents an under-estimated value, as discussed.

Biochim Biophys Acta, 1977 Aug 15, 469(1), 45 - 51
Discrimination between Rb+ and K+ by Escherichia coli; Rhoads DB et al.; 1 . The K+ requirment of Escherichia coli is only partially fulfilled by Rb+ . The molar growth yield on Rb+ was about 5% of that on K+ and the growth rate in Rb+-supplemented media is lower thatn in K+ influx by any of the four K+ transport systems of E . coli . The high-affinity Kdp system (Km = 2 micron) is poorly traced by 86Rb+ . It discriminates against a 86Rb+ tracer at least 1000-fold . The two moderate affinity systems, the high-rate TrkA system (Km = 1.5 mM) and the moderate rate TrkD system (Km = 0.5 mM), discriminate against a 86Rb+ tracer by approximately 10-fold and 25-fold, respectively . 86Rb+ is preferred by the low-rate TrkF system and overestimates its K+ influx by 40%.

Eur J Biochem, 1977 Aug 15, 78(1), 153 - 9
Physical studies on the conformation of ribosomal protein S4 from Escherichia coli; Morrison CA et al.; Proton magnetic resonance, circular dichroism and infrared spectroscopy were used to investigate the secondary and tertiary structure of the 16-S RNA binding protein S4 from Escherichia coli ribosomes . The proton magnetic resonance spectra of protein S4 in ribosomal reconstitution and low-salt buffers were identical and showed little dipolar broadening of the peaks, suggesting that the protein had an open extended structure . A ring-current-shifted apolar methyl resonance in the high-field region of the spectrum, together with a perturbation of the tyrosine ring proton resonance in the low-field region, indicated the existence of a specific tertiary fold in the polypeptide chain . This structure disappeared on lowering the pH below 5 or on heating above 30 degrees C, both processes being reversible . Circular dichroism measurements on protein S4 showed an alpha-helix content of 32% in reconstitution buffer compared with 26% in low-salt buffer . Heating the protein solution in reconstitution buffer above 35 degrees C reversibly disrupted this extra helix . Infrared studies on both solid films and solutions of protein S4 indicated the presence of little or no beta-structure . These results correlate well with the known RNA binding properties of protein S4.

MMW Munch Med Wochenschr, 1977 Aug 12, 119(32-33), 1029 - 34
{Viruses as causal agents of gastroenteritis in infants and young children (author's transl)}; Maass G et al.; Electron microscopic examination of stool samples from 195 infants and young children with acute gastroenteritis revealed rota virus in 31 samples (= 16%), corona virus in 44 samples (= 23%) and adenovirus in 13 samples (= 7%) . Viruses were excreted for between 4 and 8 days in patients infected with rota virus and corona virus respectively . An outbreak of acute gastroenteritis in a premature baby unit with 24 cases is reported: corona virus was found in the stools of 15 infants . It is suggested that corona virus as well as rota virus may cause gastroenteritis in infants and small children.

J Biol Chem, 1977 Aug 10, 252(15), 5584 - 8
Purification and some properties of Escherichia coli tRNA nucleotidyltransferase; Schofield P et al.; Adenylyl (cytidylyl)-tRNA nucleotidyltransferase (ATP (CTP): tRNA adenylyl (cytidylyl)transferase, EC2.7.7.25) has been purified 11,800-fold from a crude extract of Escherichia coli B in an overall yield of 23% . The key step in this purification is the use of a tRNA-Sepharose affinity column . The purified enzyme has a specific activity of approximately 280 mumol of AMP incorporated/min/mg of protein at 37 degrees and has a molecular weight of 52,000 as determined by sodium dodecyl sulfate gel electrophoresis of Sephadex chromatography . The turnover number of the pure enzyme, under optimal assay conditions, is estimated as 21,000, and we believe it constitutes only o.oo6% of the total cellular protein . Both AMP- and CMP-incorporating activities have an identical isoelectric point of 5.85 . The AMP-incorporating activity of the enzyme is inhibitied by some transition metal chelating agents but not by others.

J Biol Chem, 1977 Aug 10, 252(15), 5488 - 90
Mechanism of the apparent regulation of Escherichia coli unsaturated fatty acid synthesis by exogenous oleic acid; Polacco ML et al.; Starvation of strains of Escherichia coli which are glycerol auxotrophs and are also defective in beta oxidation results in the accumulation of large amounts of free fatty acid (Cronan, J . E., Jr., Weisberg, L . W., and Allen, R . G . (1975) J . Biol . Chem . 250, 5835-5840) . We now report that addition of exogenous oleic acid to these cultures results in no decrease in the synthesis of the unsaturated acids of the free fatty acid fraction although a 40 to 60% decrease of {14C}acetate incorporation into phospholipid unsaturated acyl moieties occurs under these conditions . This result indicates that the decreased synthesis of phospholipid unsaturated acyl moieties observed by others during oleic acid supplementation can be attributed to competition between exogenous and endogenously synthesized unsaturated fatty acids rather than a curtailment of unsaturated fatty acid synthesis per se.

J Biol Chem, 1977 Aug 10, 252(15), 5403 - 7
Binding of Escherichia coli RNA polymerase to T7 DNA . Displacement of holoenzyme from promoter complexes by heparin; Pfeffer SR et al.; Escherichia coli RNA polymerase holoenzyme bound to promoter sites on T7 DNA is attacked and inactivated by the polyanion heparin . The highly stable RNA polymerase-T7 DNA complex formed at the major T7 A1 promoter can be completely inactivated by treatment with heparin, as shown by monitoring the loss of activity of such complexes, and by gel electrophoresis of the RNA products transcribed . The rate of this inactivation is much faster than the rate of dissociation of RNA polymerase from promoter complexes, and thus represents a direct attack of heparin on the polymerase molecule bound at promoter A1 . Experiments employing the nitrocellulose filter binding technique suggest that heparin inactivates E . coli RNA polymerase when bound to T7 DNA by directly displacing the enzyme from the DNA . RNA polymerase bound at a minor T7 promoter (promoter C) is much less sensitive to heparin attack than enzyme bound at promoter A1 . Thus, the rate of inactivation of RNA polymerase-T7 DNA complexes by heparin is dependent upon the structure of the promoter involved even though the inhibitor binds to a site on the enzyme molecule.

J Biol Chem, 1977 Aug 10, 252(15), 5332 - 6
Threonine-sensitive homoserine dehydrogenase and aspartokinase activities of Escherichia coli K12 . Kinetic and spectroscopic effects upon binding of serine and threonine; Costrejean JM et al.; The two threonine-sensitive activities aspartokinase and homoserine dehydrogenase are inhibited by L-serine . The inhibition of the aspartokinase by L-serine displays homotropic cooperative effects and is competitive versus aspartate . The inhibition by L-serine of the homoserine dehydrogenase displays Michaelis-Menten kinetics which are of a competitive nature versus homoserine . Characteristic effects of L-serine on the protein include a perturbation of its absorption and fluorescence spectra, with an increase in the fluorescence of the protein-NADPH complex . L-serine shifts the allosteric equilibrium of the protein to a "T-like" conformation to which L-threonine binds noncooperatively . L-Serine, a threonine analog, is not capable, as the physiological effector, of inducing a complete R to T transition of the enzyme; the aspartokinase globules show a cooperative conformation change upon serine binding, but this conformation change is not found in the homoserine dehydrogenase globules.

J Biol Chem, 1977 Aug 10, 252(15), 5589 - 97
Kinetic mechanism of tRNA nucleotidyltransferase from Escherichia coli; Williams KR et al.; A kinetic analysis of the incorporation of AMP into tRNA lacking the 3'-terminal residue by tRNA nucleotidyltransferase (EC 2.2.7.25) from Escherichia coli is presented . Initial velocity studies demonstrate that the mechanism is sequential and that high concentrations of tRNA give rise to substrate inhibition which is noncompetitive with respect to ATP . In addition, the substrate inhibition is more pronounced in the presence of pyrophosphate, which suggests the formation of an inhibitory enzyme-pyrophosphate-tRNA complex . Noncompetitive product inhibition is observed between all possible pairs of substrates and products . ADP and alpha,beta-methylene adenosine triphosphate are competitive dead end inhibitors of ATP, while the latter is a noncompetitive dead end inhibitor of the tRNA substrate . A nonrapid equilibrium random mechanism is proposed which is consistent with these data and offers an explanation for the noncompetitive substrate inhibition by tRNA.

J Biol Chem, 1977 Aug 10, 252(15), 5431 - 6
Characterization of the glutamine site of Escherichia coli guanosine 5'-monophosphate synthetase; Zalkin H et al.; Alkylation of guanosine 5'-monophosphate (GMP) synthetase with the glutamine analogs L-2-amino-4-oxo-5-chloropentanoic acid (chloroketon) and 6-diazo-5-oxonorleucine (DON) inactivated glutamine- and NH3-dependent GMP synthetase . Inactivation exhibited second order kinetics . Complete inactivation was accompanied by covalent attachment of 0.4 to 0.5 equivalent of chloroketon/subunit . Alkylation of GMP synthetase with iodacetamide selectively inactivated glutamine-dependent activity . The NH3-dependent activity was relatively unaffected . Approximately 1 equivalent of carboxamidomethyl group was incorporated per subunit . Carboxymethylcysteine was the only modified amino acid hydrolysis . Prior treatment with chloroketone decreased the capacity for alkylation by iodacetamide, suggesting that both reagents alkylate the same residue . GMP synthetase exhibits glutaminase activity when ATP is replaced by adenosine plus PPi . Iodoacetamide inactivates glutaminase concomitant with glutamine-dependent GMP synthetase . Analysis of pH versus velocity and Km data indicates that the amide of glutamine remains enzyme bound and does not mix with exogenous NH3 in the synthesis of GMP.

Biochemistry, 1977 Aug 9, 16(16), 3603 - 7
A new mutation affecting ribosomal RNA synthesis in Escherichia coli; Chaney SG et al.; A temperature-sensitive mutant of Escherichia coli is described . At the nonpermissive temperature there is a 12-fold reduction in the rate of rRNA synthesis, while tRNA and mRNA syntheses are affected to only a slight extent . Both protein and DNA syntheses also continue at nearly the normal rate . The mutation appears to affect the synthesis of 16S and 23S rRNA equally and has no detectable affect on rRNA maturation . The temperature-sensitive lesion appears to be caused by a single point mutation lying between minutes 21 and 27 . It is suggested that this mutation seems to define a new genetic locus involved in the regulation of rRNA synthesis.

Biochemistry, 1977 Aug 9, 16(16), 3633 - 40
Incorporation of phosphorothioate groups into fd and phi X174 DNA; Vosberg HP et al.; We have synthesized fd and phi X174DNA in the presence of 2'-deoxyadenosine 5'-O-(1-thiotriphosphate) (dATP alpha S) and the corresponding phosphorothioate derivatives of dCTP and dTTP using ether-permeabilized E . coli cells or crude cell extracts of E . coli DNA polymerase I . Reaction rates of enzymes involved in the formation or breakdown of DNA are decreased in the presence of phosphorothioates . The amount of label incorporated with {35S}dATP alpha S suggests that the dAMP has been completely substituted by 2'-deoxyadenosine 5'-0-phosphorothioate (dAMPS) . The substituted DNAs have the same sedimentation coefficients, similar buoyant density, infectivity, and thermal stability as the unsubstituted DNAs . The procedure therefore allows specific modification at the 5' position of dA, dC, or dT in the DNA . In view of the recent demonstration of specific binding of Pt2+ complexes to the phosphorothioate analogue of poly{r(A-U)} (Strothkamp, K.G., and Lippard, S.J . (1976), Proc . Natl . Acad . Sci . U.S.A . 73, 2536), the synthesis of phosphorothioate containing DNA may be of use for DNA sequencing by electron microscopy.

Biochemistry, 1977 Aug 9, 16(16), 3721 - 6
Modification of ribonucleic acid by vitamin B6 . 1 . Specific interaction of pyridoxal 5'-phosphate with transfer ribonucleic acid; Kopelovich L et al.; Whole tRNA preparation obtained from a human cell line (HT-29) of colon carcinoma and purified specific Escherichia coli tRNA were reacted with pyridoxal 5'-phosphate, reduced by sodium borohydride and digested with RNase A and snake venom phosphodiesterase . Two-dimensional chromatography of the pyridoxal 5'-phosphate treated tRNA digest showed that pyridoxal 5'-phosphate binds specifically to GMP, presumably in the form of a Schiff base with the exocyclic amino group of the purine . The reaction of pyridoxal 5'-phosphate with whole tRNA was competitively inhibited by N-acetoxy-2-acetylaminofluorene . This suggests that binding occurred primarily to the G20 base residue at the unpaired region of the dihydrouridine loop (Fujimura et al., 1972) . The modification of tRNA by pyridoxal 5'-phosphate resulted in the inhibition, to varying extent (10-80%), of amino acid acceptance in the aminoacyl-tRNA synthetase reaction . Defects in codon recognition by pyridoxal 5'-phosphate modified amino acid acylated tRNAs in the presence of the corresponding guanine-containing polynucleotide triplets were observed by the ribosomal binding assay.

Biochemistry, 1977 Aug 9, 16(16), 3576 - 81
Partial purification and characterization of an N2-guanine RNA methyltransferase from chicken embryos; Izzo P et al.; An N2-guanine RNA methyltransferase has been purified 1000-fold from chick embryo homogenates by phosphocellulose chromatography followed by chromatography on S-adenosylhomocystein-Sepharose . The enzyme was shown to methylate the G10 position of Escherichia coli B tRNAPhe and has a Km of 3X10(-7) M for tRNAPhe and 1.38 X 10(-6) M for S-adenosylmethionine . The molecular weight was estimated to be 77 000 by gel filtration and the pH optimum was 8.0 to 8.5 . Magnesium ion was not required for activity but it stimulated the rate of methylation 1.5-fold with an optimum at 12 mM . Ammonium ion stimulated activity about twofold with an optimum at about 83 mM . Sodium and potassium ions above 0.1 M were inhibitory.

Biochemistry, 1977 Aug 9, 16(16), 3566 - 72
Escherichia coli dihydrofolate reductase: isolation and characterization of two isozymes; Baccanari DP et al.; A combination of affinity column chromatography and preparative gel electrophoresis has been used to purify to homogeneity the two isozymes of dihydrofolate reductase from a trimethoprim-resistant strain of Escherichia coli B (RT 500) . These enzyme forms are noninterconvertible and are present in crude cell lysates, but other electrophoretic species can be generated durng purification if sulfhydryl-protecting agents, such as dithiothreitol, are not present . The two isozymes, numbered form 1 and form 2 with respect to their decreasing electrophoretic mobilities, have similar molecular weights (18 500), molecular radii (21 A), and apparent Km values for reduced nico inamide adenin- dinucleotide (NADH) and NADH phosphate (NADPH) . Both forms contain 2 mol of sulfhydryl/mol of enzyme which can be oxidized to intramolecular disulfide bonds . However, forms 1 and 2 differ physically in their electrophoretic mobility and isoelectric point and kinetically in their pH-activity profile, specific activity, Km for dihydrofolate, and their affinity toward a number of inhibitors.

Science, 1977 Aug 5, 197(4303), 582 - 5
One strand equivalent of the Escherichia coli genome is transcribed: complexity and abundance classes of mRNA; Hahn WE et al.; DNA-RNA hybridization experiments show that essentially all of the genomic information is transcribed . High, intermediate, and rare abundance classes of messenger RNA (mRNA) are present, and their estimated complexities are equal to about 240, 1300, and 700 average-sized mRNA species, respectively . The high abundance mRNA species are present, an average, two to three copies per cell and constitute about 95 percent of the mRNA mass . Intermediate abundance mRNA species are present, on average, about once per 35 cells . The relative abundance and complexity of these mRNA classes correspond well with previous respective measurements on protein . Rare RNA species are thought to represent maximally repressed genes . Analysis of RNA synthesized in vitro by isolated nucleoids (chromosomes) suggests that sense and nonsense sequences are extensively interspersed on a given strand of the DNA.

Biochim Biophys Acta, 1977 Aug 2, 477(3), 221 - 7
Polyamine levels in Escherichia coli during nutritional shiftup and exponential growth; Boyle SM et al.; At different exponential growth rates obtained either by varying the carbon source of the culture medium or limiting glucose uptake, intracellular levels of putrescine and spermidine were measured . Over a ten-fold increase in growth rate an approximately three-fold increase in putrescine level and a 3.5-fold increase in spermidine level per cell absorbance were observed . Conditions favoring an abrupt alteration in growth rate, such as occur following nutritional shiftup of Escherichia coli, resulted in a significant increase in the intracellular level of putrescine and virtually no change in the spermidine level . Because of the magnitude and the timing of the change in polyamine levels, the hypothesis that polyamines are (the components) responsible for inducing the rapid increase in the rate of RNA synthesis following nutritional shiftup is rejected.

Biochem J, 1977 Aug 1, 165(2), 237 - 45
Characterization of double-stranded ribonucleic acid sequences present in the initial transcription products of rat liver chromatin; Pays E; At low ionic strength and with a low exogenous RNA polymerase/DNA ratio, rat liver chromatin directs the synthesis in vitro of RNA sequences rich in double-stranded segments . All the transcripts contain at least one double-stranded sequence . Most of the double-stranded segments are formed by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop . They are heterogeneous in size, 35-45% of them being more than 80 nucleotides long . They contain 61-64% G+C, whether synthesized by rat liver RNA polymerase (form B) or Escherichia coli RNA polymerase . The largest double-stranded sequences are found in the largest transcripts, and are the most thermostable . The fidelity of base-matching is better in double-stranded transcripts synthesized on rat liver chromatin by homologous polymerase than in those synthesized on it by a bacterial polymerase, or in those synthesized by either of the two polymerases on pure DNA.

Immunology, 1977 Aug, 33(2), 179 - 83
Suppression and potentiation of expression of delayed-type hypersensitivity by dextran sulphate; L'Age-Stehr J et al.; Dextran sulphate delays the onset, or even completely suppresses the expression in mice of DTH or SRBC when administered via a route different from that of eliciting antigen . However, DS injected together with the eliciting antigen potential the expression of DTH . Dextran showed no effect on DTH . Cell transfer experiments suggest that the targets for the action of DS are the accessory cells (monocytes) and not the T-effector cells . As shown, using polystyrene latex particles and lipopolysaccharide from E . coli, trapping and perhaps activation of the trapped accessory cells rather than toxic effects of DS are responsible for these phenomena.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3518 - 22
Cloning of an immunoglobulin variable region gene from mouse embryo; Tonegawa S et al.; A 4.8-kilobase DNA fragment carrying an immunoglobulin gene coding for a mouse lambda chain variable region (Vlambda gene) was enriched about 350-fold from a total endonuclease EcoRI digest of embryonic DNA by a combination of preparative agarose gel electrophoresis of double-stranded DNA and CsCl density gradient centrifugation of R-loops formed with a purified lambda chain mRNA . DNA fragments thus enriched for the immunoglobulin gene were inserted in vitro in the middle of the genome of the vector phage lambdagt Wam 403, Eam 100, Sam 100 by use of the EcoRI cohesive ends . Transfection of CaCl2-treated Escherichia coli 803 {rk-, mk- (lacking restriction and modification systems for K-12)} with such hybrid DNA and subsequent screening of about 4000 plaques by in situ hybridization with purified 125I-labeled lambda chain mRNA led to isolation of a clone that carries a Vlambda gene (lambdagtWES-Ig 13) . Electron microscopy of R-loops confirmed the presence of sequences homologous to part of the lambda chain mRNA in its 5'-end.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3217 - 21
DNA-directed synthesis in vitro of beta-galactosidase: requirement for a ribosome release factor; Kung HF et al.; The DNA-directed synthesis of beta-galactosidase in Escherichia coli extracts has been investigated in a partially fractionated system . A dependency was obtained for 3',5'-cyclic AMP receptor protein and also for a factor, from the salt wash of ribosomes, that has been purified to near homogeneity . This factor has been identified with a ribosome release factor previously purified from the supernatant fraction by A . Hirashima and A . Kaji {(1972) Biochemistry 11,4037-4044} . In the coupled transcription-translation system this factor stimulates beta-galactosidase synthesis and total protein synthesis 2- to 4-fold . It is thus clear that the ribosome release factor has a physiological function in translation . It may also affect transcription, because it stimulated total RNA synthesis up to 50% in this in vitro system.

Nucleic Acids Res, 1977 Aug, 4(8), 2799 - 809
Search for revertants of the glutamine mischarging mutans of Escherichia coli su+3 tyrosine suppressor tRNA that are able to insert tyrosine at the site of amber mutation; Celis JE et al.; We have isolated a bacterial amber mutation (nadam) that is suppressed by the tyrosine inserting suppressor su+3 but not by the glutamine (su+2, su+3 A1, su+3 G82 and su+3 A1G82), serine (su+1) and leucine (su+6) inserting suppressors . The su+7 suppressor which inserts glutamine and tryptophan also suppresses this mutation indicating that tryptophan, in addition to tyrosine, is accepted at the site of amber mutation . We have used this amber mutation to search for revertants of the su+3 glutamine mischarging mutants su+3 A1, su+3 G82 and su+3 A1G82 that are able to insert tyrosine at the site of amber mutation . Two types of revertants were found in the case of su+3 A1 . One type corresponding to the true revertant A1 leads to G, and the other to the second site revertants C81 leads to U (A1U81) . The A1U81 revertant has been shown to insert both glutamine and tyrosine at the site of amber mutation . Only true revertants (G82 leads to A) were obtained when su+3 G82 was analyzed . No revertants were obtained in the case of the su+3 A1G82 . These results are discussed in relation to aminoacyl-tRNA recognition.

Hoppe Seylers Z Physiol Chem, 1977 Aug, 358(8), 1003 - 19
Secondary structures of proteins from the 30S subunit of the Escherichia coli ribosome; Dzionara M et al.; The secondary structures of the proteins S4, S6, S8, S9, S12, S13, S15, S16, S18, S20 and S21 from the subunit of the E . coli ribosome were predicted according to four different methods . From the resultant diagrams indicating regions of helix, turn, extended structure and random coil, average values for the respective secondary structures could be calculated for each protein . Using the known relative distances for residues in the helical, turn and sheet or allowed random conformations, estimates are made of the maximum possible lengths of the proteins in order to correlate these with results obtained from antibody binding studies to the 30S subunit as determined by electron microscopy . The influence of amino acid changes on the predicted secondary structures of proteins from a few selected mutants was studied . The altered residues tend to be structurally conservative or to induce only minimal local changes.

Genetics, 1977 Aug, 86(4), 715 - 25
Recombination pathway specificity of Chi; Stahl FW et al.; Chi in phage lambda is a genetic element increasing the rate of recombination in its vicinity . Chi activity requires the wild-type functions of both the recA and the recB genes of E . coli . In terms of the pathway concept for recombination, Chi is active in the RecBC pathway and inactive in the Red, RecE., and RecF pathways.

Biochem J, 1977 Aug 1, 165(2), 367 - 73
The aminoacylation of transfer ribonucleic acid . Recognition of methionine by Escherichia coli methionyl-transfer ribonucleic acid synthetase; Old JM et al.; The mechanism of the recognition of methionine by Escherichia coli methionyl-tRNA synthetase was examined by a kinetic study of the recognition of methionine analogues in the ATP-PPi exchange reaction and the tRNA-aminoacylation reaction . The results show that the recognition mechanism consists of three parts: (1) the recognition of the size, shape and chemical nature of the amino acid side chain at the methionine-binding stage of the reaction; (2) the recognition of the length of the side chain at the stage of aminoacyl-adenylate complex-formation; (3) the recognition of the sulphur atom in the side chain at the stage of methionyl-tRNA formation . It is proposed that the sulphur atom interacts with the enzyme to induce a conformational change . A model of the active site incorporating the mechanism of methionine recognition is presented.

Kidney Int, 1977 Aug, 12(2), 91 - 5
Unilateral Shwartzman reaction: cortical necrosis in one kidney following in vivo perfusion with endotoxin; Raij L et al.; Unilateral renal cortical necrosis was selectively induced by in situ perfusion of the rabbit kidney with a perfusate containing 50 microgram of endotoxin followed by the i.v . administration of 250 microgram of endotoxin 24 hr later . The results strongly support the idea that the initial event in the genesis of renal cortical necrosis during the Shwartzman reaction is a specific local effect of endotoxin on the vascular endothelium.

Am J Vet Res, 1977 Aug, 38(8), 1177 - 81
Immune responses of the bovine fetus and neonate to Escherichia coli: plaque-forming and intestinal immune responses; Olson DP et al.; The immune responses of 26 Angus-Hereford fetuses and neonates to Escherichia coli O26:K60:NM were studied after bacterin or saline solution was injected (in utero) into the amniotic fluid . Calves were euthanatized at birth or were orally revaccinated; some were challenge exposed with live organisms . The hemolytic plaque assay was used to determine the presence of cells producing immunoglobulins M, G1, and G2 (IgM, IgG1, and IgG2) in 4 segments of the small intestine, mesenteric lymph nodes, and spleen . The passive hemagglutinin activity of intestinal washings was also determined . Anti-O26 passive hemagglutinin activity in the intestinal washings of principal calves was greater than in that of control calves, but in a given segment of the small intestine, usually this activity was relatively small and less consistent than the plaque-forming response . Greater numbers of plaque-forming cells were observed in the small intestine of 14 of the 15 principal calves when compared with the control calves tested.

Zentralbl Bakteriol {Orig B}, 1977 Aug, 164(5-6), 498 - 506
{Testmethod for the evaluation of procedures for the hygienic disinfection of hands . Part 1: Discription of testmethod (author's transl)}; Rotter M et al.; A detailed test design for the evaluation of procedures for the hygienic disinfection of hands is described together with suitable methods for statistical analysis of the results . In principle the release of testbacteria from the finger-tips of artificially contaminated hands is measured before and after disinfection . A procedure under test is accepted if it is not less effective than a standard-disinfection procedure . As such the disinfection with iso-propanol 60% (ml/ml) applied through 1 min was agreed upon . This standard procedure is to be performed the same day with the same day with the same testpersons and under identical environmental conditions prior to the procedure under test.

Zentralbl Bakteriol {Orig B}, 1977 Aug, 164(5-6), 428 - 38
{Usability of three alcohols for a standard disinfection method to be employed for the evaluation of procedures for the hygienic disinfection of hands (author's transl)}; Rotter M et al.; Following a former suggestion (4) always to evaluate, the efficacy of procedures for Hygienic disinfection of hands in comparison with the results of a certain standard disinfection method, Ethanol, iso- and n-Propanol were tested in various concentrations and for various times of action on their usability in such a standard method . The disinfecting power was dependent upon (i) the alcohol (Ethanol less than iso-Propanol less than n-Propanol), (ii) the concentration (Ethanol: 60 less than 70 less than 80% ml/ml, iso-Propanol: 50 less than 60 less than 70, n-Propanol: 40 less than 50 less than 60 = 70) and (iii) the time of action (0,5 less than 1 less than 2 min) . n-Propanol proved to be the fastest acting disinfectant . However, as standard disinfection method iso-Propanol (60% ml/ml) being used for 1 min has been proposed . Furthermore, the following results that have been obtained also in former investigations (8) could be confirmed: (i) there is no systematic difference between the release of test-bacteria from the fingertips of right and left hands of test-persons (ii) . The efficacy of procedures for Hygienic disinfection of hands is besides other factors influenced by the testpersons . This factor may be eliminated by using the same testpersons for both, the disinfection procedure under investigation and the standard method . The results of both may, then, be related to each other and the efficacy of the former may be evaluated in comparison to the latter.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3335 - 9
Mechanism of phage phiX174 DNA inactivation by benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide; Hsu WT et al.; A previous report from this laboratory has shown that certain derivatives of polycyclic aromatic hydrocarbons bind to phiX174 DNA and render it noninfectious . The present work describes the relationship between the extent of phiX174 DNA binding by (+/-)-anti-benzo{a}pyrene-7,8-dihydrodiol-9,10-epoxide and the effect on infectivity . The results suggest that one molecule of bound diolepoxide is sufficient to inhibit the replication of a single molecule of phiX174 DNA . DNA synthesis studies, in vitro, indicate that when phiX DNA bound by benzo{a}pyrene groups serves as template the rate of DNA polymerization is reduced and less product is formed . In addition, the propagation of synthetic DNA strands is blocked so that incomplete complementary chains are assembled . The relationship of these findings to the mutagenic and carcinogenic process associated with the action of benzo{a}pyrene-diolepoxide is discussed.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3312 - 6
Sensory transduction in Escherichia coli: two complementary pathways of information processing that involve methylated proteins; Springer MS et al.; The properties of two classes of behavioral mutants of Escherichia coli (called tsr and tar) are described . The mutations in these strains define two complementary pathways of information flow in bacterial chemotaxis: behavioral responses to one set of stimuli are defective in tsr mutants, while responses to a complementary set of stimuli are defective in tar mutants . A double mutant containing both genetic lesions is defective in responses to all stimuli tested . The behavioral defects are shown to correlate with alterations in the properties of a methylation reaction involved in chemotaxis . Two independent sets of methyl-accepting proteins are demonstrated in the wild type, each set functioning in one of the two pathways mentioned above . Methylation of one set of proteins is defective in tsr mutants, while methylation of the complementary set is defective in tar mutants . The double mutant shows no methylation of either set . The relationship between the genetic loci (tsr and tar) and the methyl-accepting proteins is discussed.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3143 - 7
State of prophage Mu DNA upon induction; Ljungquist E et al.; We have compared the process of prophage lambda induction with that of prophage Mu . According to the Campbell model, rescue of lambda DNA from the host DNA involves reversal of lambda integration such that the prophage DNA is excised from the host chromosome . We have monitored this event by locating the prophage DNA with a technique in which DNA of the lysogenic cells is cleaved with a restriction endonuclease and fractionated in agarose gels . The DNA fragments are denatured in gels, transferred to a nitrocellulose paper, and hybridized with 32P-labeled mature phage DNA . The fragments containing prophage DNA become visible after autoradiography . Upon prophage lambda induction, the phage-host junction fragments disappear and the fragment containing the lambda att site appears . No such excision is seen in prophage Mu . The Mu-host junction fragments remain intact well into the lytic cycle, when Mu DNA has undergone many rounds of replication and apparently many copies of Mu DNA have been integrated into the host DNA . Therefore, we postulate that Mu DNA replicates in situ and the replication generates a form of Mu DNA active in the integrative recombination between Mu DNA and host DNA . This type of mechanism may be common to many transposable elements.

Nucleic Acids Res, 1977 Aug, 4(8), 2881 - 92
On the Phe-tRNA induced binding of fluorescent oligonucleotides to the ribosomal decoding site; Menzel HM; Fluorescent oligonucleotides were prepared by dansylation of 5'-amino uridylates of varying chainlength . Except for the trinucleoside diphosphate, they stimulated the binding of PhetRNA TO 70S E . coli ribosomes as efficiently as underivatised oligouridylic acids of comparable chainlength . The ternary ribosomal complex {70S X Phe-tRNA X dansyl-n5'U(pU)4} was separated from excess oligonucleotide and its fluorescence spectra were measured . The quantum yield of the dansylated pentauridylate was enhanced 2.5 fold when bound to the ribosomal decoding site, but no shift of the emission spectrum was observed . The ribosomal complex is considered useful for topographic investigations by singlet energy transfer, using the functionally defined decoding site as reference point.

Nucleic Acids Res, 1977 Aug, 4(8), 2871 - 9
Relation between Escherichia coli endonucleases specific for apurinic sites in DNA and exonuclease III; Ljungquist S et al.; Contradictory data have recently been published from two different laboratories on the presence vs absence of an intrinsic endonucliolytic activity of E . coli exonuclease III at apurinic sites in double-stranded DNA . It is shown here that an endonuclease activity of this specificity co-chromatographs exactly with exonuclease III on phosphocellulose and Sephadex G-75 columns, indicating that the endonuclease and exonuclease activities are due to the same enzyme . In addition, another E . coli endonuclease specific for apurinic sites exists, which can be separated from exonuclease III by the same chromatographic procedures.

Nucleic Acids Res, 1977 Aug, 4(8), 2767 - 77
Modified polynucleotides . I . Investigation of the enzymatic polymerization of 5-alkyl-dUTP-s; Sagi JT et al.; The chemical synthesis of 5-alkyl-dUTP-s and their participation as substrates in poly{d(A-6)} primed polymerization reactions with dATP by E . coli DNA polymerase I enzyme has been described . In comparison with dTTP, at saturating substrate concentrations, the rate of hypochromic effect was found to be 17.3% higher for dUTP and was lower by 27.4% for 5-ethyl-dUTP, 29.5% for 5-n-propyl-dUTP, 31.4% for 5-n-butyl-dUTP and by 85.0% for 5-n-pentyl-dUTP . No hypochromic effect could be observed, however, with 5-iso-propyl-, 5-tert.butyl- and 5-n-hexyl-dUTP-s . Polydeoxynucleotides have also been isolated from the reaction mixture and some of their structural properties determined.

J Med Chem, 1977 Aug, 20(8), 1055 - 9
2-Deaminoactinomycin D, synthesis and interaction with deoxyribonucleic acid; Mosher CW et al.; 2-Deaminoactinomycin D has been synthesized and characterized . It binds to DNA by intercalation according to NMR, CD, thermal denaturation, and unwinding studies on the drug-DNA complex . Loss of the 2-amino group does not seriously affect binding parameters relative to actinomycin D; affinity for calf thymus DNA may even be increased, according to deltaTm measurements . The unwinding of circular DNA caused by this compound is at least as large as that effected by actinomycin D and ethidium bromide . Nevertheless, 2-deaminoactinomycin D is less effective than actinomycin D in inhibiting nucleic acid syntheses in L1210 cell culture and in in vivo antitumor activity against P388 leukemia.

J Infect Dis, 1977 Aug, 136 Suppl, 124 - 9
Intestinal colonization and adhesion by enteroxigenic Escherichia coli: ultrastructural observations on adherence to ileal epithelium of the pig; Moon HW et al.; Colonization of pig ileum by enterotoxigenic Escherichia coli that were enteropathogenic for pigs but that lacked K88 antigen (K88-) resulted in morphological characteristics similar to those reported for K88+ strains . Strains of enterotoxigenic E . coli from three different K88-serotypes adhered to the villous epithelium . In sections examined by transmission electron microscopy, adherent bacteria were separated from each other and from epithelial microvilli by peribacterial electron-lucent regions . The enterotoxigenic E . coli had appendages that extended into these regions . The appendages were morphologically characteristic for each strain . It is possible that these appendages were pili, polysaccharide K antigens, or structures resulting from some interaction between pili and polysaccharide . Certain pili or pilus-like structures may be virulence attributes that facilitate adhesion of enterotoxigenic E . coli to the intestinal epithelium.

J Infect Dis, 1977 Aug, 136 Suppl, S118 - 23
Virulence factors of enterotoxigenic Escherichia coli; Evans DG et al.; Further evidence for the role of enterotoxigenic Escherichia coli as an etiologic agent of diarrhea is presented . A retrospective study of 71 cases of diarrhea in Mexican children demonstrated that greater than 40% of them harbored E . coli that produced heat-labile and/or heat-stable enterotoxin . The antigenic surface-associated colonization factor of E . coli strain H-10407 has been further characterized: this pilus-like antigen is produced under conditions of growth that repress the production of common pili of E . coli . The E . coli H-10407-type colonization factor pilus has been identified as one of the antigens possessed by a strain of E . coli that produced only heat-stable enterotoxin and that was responsible for an outbreak of pediatric diarrhea.

J Clin Microbiol, 1977 Aug, 6(2), 124 - 7
Relationship of K1 antigen to biotype in clinical isolates of Escherichia coli; Myerowitz RL et al.; Two hundred and ninety-four isolates of Escherichia coli, including 105 from blood cultures, 94 from stools of hospital inpatients, and 96 from rectal cultures of healthy young adults, were biotyped by using the API-20E system and tested for the presence of K1 antigen . The overall frequency of K1 strains was 14.2% and was similar among the three sources . Forty-eight biotypes were observed, but two-thirds of all isolates, including two-thirds of the K1 strains, belonged to only five biotypes . Among the five commonest biotypes, the distribution of K1 strains was nonrandom, since 23 of the 27 K1 strains belonged to only two biotypes . Analysis of the O and H antigens of K1 strains indicated that this correlation of biotype with K1 antigen was due to a restricted number of serovars ("clones") that were repeatedly isolated from the population studied . These serovas included O18:K1:H7, O1:121:H6 and O16:K1:H6 . Although a statistically significant correlation between biotype and K1 antigen was observed, the correlation was not sufficiently great to alow biotyping to be of significant predictive value as a marker for the K1 antigen.

Infect Immun, 1977 Aug, 17(2), 408 - 14
Insect immunity . III . Purification and partial characterization of immune protein P5 from hemolymph of Hyalophora cecropia pupae; Pye AE et al.; We previously showed that in pupae of Hyalophora cecropia, eight hemolymph proteins (P1 through P8) were selectively synthetized after immunization (Faye et al., Infect, Immun . 12:1426-1438, 1975) . We also showed that a gross fractionation was obtained by a series of ammonium sulfate precipitations (designed A through D) and that protein P5 was enriched in fraction A . Starting from fraction A, we have now purified protein P5 by using dialysis, isoelectric focusing, and hydroxylapatite chromatography . The final product gave a single band in both gradient gel and sodium dodecyl sulfate-polyacrylamide gel electrophoresis . Using the latter method, proteins P5 and P8 were found to be enriched in fraction A, but they were absent in fraction Ac prepared from nonimmunized pupae . Protein P5 was found to have a pI of 6.6 and a molecular weight of 24,000 in sodium dodecyl sulfate and 96,000 in tris (hydroxymethyl) aminomethane-borate, pH 9.0 . These data suggest a structure for P5 composed of four subunits of equal size . Protein P5 stimulated the killing of Escherichia coli by hemolymph fractions B and D, but it had neither killing nor phenol oxidase activity of its own.

Infect Immun, 1977 Aug, 17(2), 389 - 94
Effect of alkali-treated lipopolysaccharide on the intracellular cations of human erythrocytes; Warren JR et al.; The adsorption to human erythrocytes of Escherichia coli lipopolysaccharide treated by mild alkaline hydrolysis (h-LPS) stimulated an increase in the intracellular Na+ concentration and a decrease in the intracellular K+ concentration of the erythrocytes . Erythrocytes treated by h-LPS remained responsive to the membrane adenosine triphosphatase inhibitors ouabain and ethacrynic acid, indicating that hLPS did not alter erythrocyte cations be depleting energy intermediates or uncoupling energy metabolism from active cation transport . The h-LPS-treated erythrocytes became non-agglutinable by the lectin concanavalin A prior to the development of changes in intracellular cations . In addition, h-LPS-treated erythrocytes demonstrated a three-fold greater cation response to ethacrynic acid than the untreated erythrocytes; this greater response was probably due to local membrane effects by h-LPS on the ethacrynic acid-sensitive adenosine triphosphatase . It is suggested that the h-LPS-induced alteration of erythrocyte cation content was secondary to an increase in ion permeability localized to the concanavalin A receptor regions of the erythrocyte membrane, possibly combined with indirect effects of membrane-bound h-LPS on ethacrynic acid-sensitive adenosine triphosphatase.

Eur J Pharmacol, 1977 Aug 1, 44(3), 197 - 204
The antipyretic effect of flurbiprofen; Van Miert AS et al.; Flurbiprofen, like its predecessor ibuprofen, possesses antipyretic properties in the endotoxin-fevered rabbit . Comparison of flurbiprofen and ibuprofen at varying dosages, reveals that flurbiprofen is at least 15 times more potent in this species . In goats, flurbiprofen is more potent than in rabbits . Flurbiprofen inhibited the pyrogenic effect of intravenously administered leucocytic pyrogen, but it did not alter the release of leucocytic pyrogen from peritoneal exudate cells in vitro . Moreover, flurbiprofen did not inhibit endotoxin-induced release of endogenous pyrogen in vivo . Incubation of leucocytic pyrogen with flurbiprofen did not alter its pyrogenic poteny . These results suggest that the antipyretic activity of flurbiprofen is due neither to interference with endogenous pyrogen synthesis and release, nor to inactivation of circulating endogenous pyrogen.

Can J Microbiol, 1977 Aug, 23(8), 1069 - 77
Reduced synthesis of beta-galactosidase in Escherichia coli infected with phage phi X 174; Ghosh A et al.; The synthesis of beta-galactosidase (EC 3.2.1.23;beta-D-galactoside galactohydrolase) in E . coli was repressed as a result of infection with single-stranded DNA phage phi chi 174 . Evidence is presented to show that this repression was not due to the restricted entry of the inducer molecules into the infected cells but to some phage-specified product(s) . It was further shown that either the infected cells synthesized a fewer number of enzyme-specific mRNA or all such molecules were translated with a reduced efficiency; the half-lives of the mRNA's remained more or less unaffected.

J Hyg (Lond), 1977 Aug, 79(1), 43 - 5
The effect of diet on intestinal Escherichia coli; Bettelheim KA et al.; During an 8-week period all specimens of stool passed by six nurses were examined for the presence of Escherichia coli and all isolations of this organism were serotyped . During the middle 4 weeks of the period the nurses ate a sterile diet . A smaller number of serotypes was isolated during the period of sterile diet than during the period when normal food was eaten . This finding supports the view that normal food is a source of strains of E . coli present in the bowel . Some new serotypes of E . coli did appear during the period of sterile diet . The possible sources of these are discussed.

J Bacteriol, 1977 Aug, 131(2), 685 - 8
Secondary promoter of the guanine operon of Escherichia coli K-12; Fukumaki Y et al.; Evidence of a secondary promoter for the guaA gene within the guaB gene was obtained by using lambdapguaA transducing phage . The technique is generally applicable to distinguish a promoter present within a bacterial deoxyribonucleic acid segment, which has replaced the lambda b2 region of transducing phage, from the phage pI promoter.

J Bacteriol, 1977 Aug, 131(2), 631 - 7
Role of a major outer membrane protein in Escherichia coli; Lutkenhaus JF; Mutants of Escherichia coli B/r lacking a major outer membrane protein, protein b, were obtained by selecting for resistance to copper . These mutants showed a decreased ability to utilize a variety of metabolites when the metabolites were present at low concentrations . Also, mutants of E . coli K-12 lacking proteins b and c from the outer membrane were shown to have an identical defect in the uptake of various metabolites . These results are discussed with regard to their implications as to the role of these proteins in permeability of the outer membrane,

J Bacteriol, 1977 Aug, 131(2), 572 - 82
Characterization of lexB mutations in Escherichia coli K-12; Morand P et al.; Two mutations have been located at the recA locus and phenotypically characterized along with a third one, previously called rec-34 . The three mutants behaved similarly to lexA mutants . They were sensitive to ultraviolet (UV) light and X rays, and lambdaFec- phages were able to plate on them . The three mutations were called lexB because they could be distinguished from recA mutations by the last property . lexB mutants were less sensitive to UV and X irradiations than were recA mutants and were, to various degrees, recombination proficient . UV light failed to induce prophage lambda in all three lexB lysogens . In contrast, thymine starvation induced lexB31 and lexB34 lysogens . In lexB34 mutants, but not in lexB30 and lexB31 mutants, UV reactivation occurred at a low level . In Escherichia coli K-12, the recA gene has basic functions in the repair of deoxyribonucleic acid lesions, deoxyribonucleic acid recombination, and prophage induction . The three lexB mutations alter unequally and independently the three functions . This suggests that the recA and lexB mutations affect the same gene.

J Bacteriol, 1977 Aug, 131(2), 512 - 8
Restoration of phosphate transport by the phosphate-binding protein in spheroplasts of Escherichia coli; Gerdes RG et al.; Reconstitution of phosphate transport in Escherichia coli was demonstrated . Conversion of E . coli K10 cells to spheroplasts decreased phosphate transport to about 2% . Addition of purified phosphate-binding protein at physiological levels to these spheroplasts caused a mean 14-fold increase in phosphate transport rate . Crude shock fluid fractions were also stimulatory but not if the shock fluid was obtained from mutants lacking phosphate-binding protein . The effect of the binding protein was abolished by its specific antibody . The phosphate was shown to have entered the cell, where it became esterified . Reconstitution was not possible with cold-shocked or osmotically shocked cells.

J Bacteriol, 1977 Aug, 131(2), 505 - 11
Two systems for the uptake of phosphate in Escherichia coli; Rosenberg H et al.; Mutants of Escherichia coli K-12 were constructed such that each possessed one single major system for phosphate transport . A comparison of these strains showed that one of the systems (PIT) was fully constitutive, required no binding protein, and operated in spheroplasts . It permitted the complete exchange of intracellular phosphate with extracellular phosphate (or arsenate) and was completely inhibited by uncouplers . The other system, PST, was repressible by phosphate concentrations above 1 mM, required the phosphate-binding protein for full activity, and did not operate in spheroplasts . It catalyzed very little exchange between internal and external phosphate and was resistant to uncouplers . The maximal velocities attained by the two systems were approximately the same, but the affinity for phosphate in the PST system was greater by two orders of magnitude . In strains in which both systems were fully operative, the initial rates of uptake was nearly additive, and the systems appeared to interact with a common intracellular phosphate pool.

J Bacteriol, 1977 Aug, 131(2), 499 - 504
Chromosome structure of Escherichia coli mutants temperature sensitive for deoxyribonucleic acid replication; Cunningham RP et al.; Folded chromosomes were isolated from Eschericia coli thermosensitive dnaA initiation mutants incubated at the nonpermissive temperature and were analyzed by neutral sucrose density gradient centrifugation . A chromosomal structure that sedimented at approximately 1,500S accumulated when the dnaA gene product was inactive . When the cells were returned to a permissive temperature, the folded chromosomes exhibited a decrease in sedimentation velocity to 1,300S but still retained their uniform structure . Very little deoxyribonucleic acid synthesis occurred during the period in which the chromosomes exhibited the reduction in sedimentation velocity . A dnaG elongation mutant showed no unique chromosome structure when the dnaG gene product was inactive.

J Bacteriol, 1977 Aug, 131(2), 431 - 7
Induction of alkaline phosphatase in Escherichia coli: effect of procaine hydrochloride; Tribhuwan RC et al.; The effect of procaine hydrochloride, an anesthetic known to alter membrane structure, on the induced formation of alkaline phosphatase, a periplasmic enzyme, in Escherichia coli was investigated . Procaine hydrochloride specifically arrested the appearance of active alkaline phosphatase while permitting the induction of another enzyme, beta-galactosidase, which is internally localized . Evidence has been obtained to show that procaine hydrochloride does not arrest synthesis of inactive monomer subunits of the enzyme, indicating that the drug interferes in the conversion of monomer subunits to an active dimer enzyme.

J Bacteriol, 1977 Aug, 131(2), 421 - 30
Suppression of an Escherichia coli dnaA mutation by the integrated R factor R100.1: origin of chromosome replication during exponential growth; Chandler M et al.; We have investigated the behavior, during exponential growth, of strains of Escherichia coli carrying a dnaA(Ts) mutation that has been suppressed by the integration of the F-like R plasmid R100.1 . We present evidence showing that replication in these strains proceeds largely from the normal chromosome origin at 30 degrees C, a permissive temperature for the dnaA(Ts) gene product, whereas, at 42 degrees C, replication proceeds largely from the integrated plasmid . These conclusions are based on measurements made by deoxyribonucleic acid:deoxyribonucleic acid hybridization of the relative frequencies of the prophages Mu-1 and lambdaind- and R100.1 integrated at known locations on the E . coli chromosome in these Hfr strains.

J Bacteriol, 1977 Aug, 131(2), 413 - 20
Further characterization of the F fertility inhibition systems of "unusual" Fin+ plasmids; Gasson MJ et al.; Flac mutants insensitive to transfer inhibition by R factors . JR66a and R485 were isolated and characterized . Representative mutations were cis dominant and are therefore presumed to be at the sites of action, fisU and fisV, respectively, of the FinU and FinV transfer inhibition systems encoded by JR66a and R485 . The mutants were used to confirm that the FinU and FinV fertility inhibition systems are different from each other and from the FinOP, FinQ, and FinW systems of R100, R62, and R455, respectively . Together with traO and fisQ mutants of Flac, the new mutants were also used to investigate the nature of the F fertility inhibition systems encoded by a further group of "unusual" Fin+ plasmids . Of these, two incompatibility group X plasmids were found to carry finO+ genes, and of five incompatibility group I plasmids, three encoded FinQ systems, one the FinU system, and one a new system (FinR) . Transfer of a variety of derepressed F-like plasmids was inhibited by the FinQ, FinU, and FinV systems, but a quantitatively very different levels; this emphasizes the differences as well as the similarities between the conjugation systems of F-like plasmids.

Arch Otolaryngol, 1977 Aug, 103(8), 441 - 4
Effect of inflammatory mediators on nasal mucosa; Jackson RT et al.; A technique used for study of permeability and vasodilation in the middle ear has been adapted to study the response of nasal mucosa to common inflammatory mediators involved in the natural production of allergic or infectious rhinitis . All of the mediators tested (histamine, prostaglandin E1, bradykinin, the C3a fraction of complement, Escherichia coli endotoxin, and lysozyme) were found to increase nasal permeability to the isotopic tracer 99mTc as the pertechnetate ion . Histamine increased the permeability of nasal mucosa to technetium-labeled plasma protein . Results indicate that the nasal mucosa is approximately ten times as permeable to the pertechnetate ion as middle ear mucosa . Nasal mucosa was also noted to be permeable to protein, even in the absence of inflammatory mediator, in contrast to prior studies of middle ear mucosa that showed little or no permeability in the absence of inflammatory mediator . In almost all cases, a corresponding change in vasodilation accompanied permeability changes.

Metabolism, 1977 Aug, 26(8), 847 - 50
Glucose kinetics in dogs following a lethal dose of endotoxin; Wolfe RR et al.; The effects of a lethal dose of Escherichia coli endotoxin on the glucose kinetics and cardiovascular responses of conscious dogs were studied . The plasma glucose level fell steadily after endotoxin administration to severely hypoglycemic levels preterminally . The fall in plasma glucose appeared to be due primarily to an increased tissue uptake in the early phase, whereas decreased hepatic glucose output also contributed in the later, preterminal phases.

J Pediatr, 1977 Aug, 91(2), 302 - 3
Heat-stable enterotoxigenic Escherichia coli and necrotizing enterocolitis: lack of an association; Ryder RW et al.; During an outbreak of diarrhea in a special care nursery caused by heat-stable enterotoxigenic Escherichia coli (serotype 078:H11:K80), nine (4.3%) of the 205 infants in the nursery developed necrotizing enterocolitis . Cases of necrotizing enterocolitis were not significantly more common in infants colonized or infected with these organisms; heat-stable enterotoxigenic E . coli was isolated from 5(56%) of nine cases of necrotizing ecterocolitis and from 27(38%) of the 71 infants without necrotizing enterocolitis who were also cultured . Our findings suggest that caution should be taken in implicating enterotoxigenic E . coli as a cause of necrotizing enterocolitis.

Proc Natl Acad Sci U S A, 1977 Aug, 74(8), 3193 - 7
Identification and cloning of the chloroplast gene coding for the large subunit of ribulose-1,5-bisphosphate carboxylase from Chlamydomonas reinhardi; Gelvin S et al.; mRNA coding for the large subunit (LS) of ribulose-1,5-bisphosphate carboxylase {3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39} from Chlamydomonas reinhardi has been isolated from small polyribosomes immunoadsorbed to column-bound anti-LS antibody . 32P-Labeled LS mRNA was used as a hybridization probe to detect LS genes . The probe hybridized to C . reinhardi chloroplast DNA and at hybridization saturation revealed that there are approximately 75 LS genes per chloroplast . When chloroplast DNA was digested with the restriction endonuclease EcoRI and the fragments were transferred to a nitrocellulose filter, the LS mRNA probe hybridized to a DNA fragment of molecular weight 3.2 X 10(6) . This same fragment codes (in part) for 16S and 23S chloroplast rRNAs, which are also coded (in part) by fragments of molecular weights 9.0, 2.3, and 0.4 X 10(6) . The restriction fragment containing the LS gene has been cloned in the Escherichia coli plasmid pMB9.

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