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