J Biol Chem, 1975 May 25, 250(10), 3660 - 5 Purification of thymidine phosphorylase from Escherichia coli and its photoinactivation in the presence of thymine, thymidine, and some halogenated analogs; Voytek P; Isoelectric focusing was used as the final step in the isolation of thymidine phosphorylase which was found to have an isoelectric point of 4.1 . Analytical acrylamide gel electrophoresis showed the purified enzyme preparation contained one major protein band which stained for thymidine phosphorylase activity and usually a minor, faster migrating band devoid of activity . Inactivation of thymidine phosphorylase alone or in the presence of sensitizers by ultraviolet light, primarily at 253.7 nm, followed first order inactivation kinetics . The rate of inactivation of the enzyme was the same at pH 5 and 7.4 and the addition of various pyrimidine bases and nucleosides enhanced the inactivation rate at both pH values, but to a greater extent at pH 5 . Linear plots of inactivation rates versus concentrations of thymidine or thymine were the same . At 7.8 mM thymidine or thymine, 11- and 4.4-fold increases in photoinactivation of thymidine phosphorylase were observed at pH 5 AND 7.4 RESPECTIVELY . Parabolic curves were obtained with increasing concentrations of either 5-iodo-2'-deoxyuridine or 5-iodouracil . 5-Iodouracil at 5.2 mM caused 212- (pH 5) and 100- (pH 7.4) FOLD INCREASES IN THE RATES OF PHOTOINACTIVATION OF THYMIDINE PHOSPHORYLASE . However, 5-iodo-2'-deoxyuridine at 5.0mM only enhanced the photoinactivation of enzyme by factors of 83 (pH 5) and 21 (pH 7.4) . Neither 5-bromo-2'-deoxyuridine or 5-bromo-uracil was as potent in sensitizing the enzyme as the iodo analogs . Combinations of 5-iodouracil or 5-iodo-2'-deoxyuridine with thymine resulted in higher inactivation rates than the additive inactivation rates of individual compounds, whereas combinations of either iodo analog with thymidine resulted in lower inactivation rates . Increasing concentrations of phosphate or NaCl lessened the photoinactivation rate of thymidine phosphorylase alone and protected the enzyme from the sensitization caused by the different bases and nucleosides . No quantitative changes in the number of primary amino groups in thymidine phosphorylase was evident as a result of irradiation in the presence or absence of 5-iodouracil or 5-iodo-2'-deoxyuridine . Examination of the irradiated enzyme on Sephadex G-150 indicated that a larger protein species is formed and that 5-iodouracil promotes this process. J Biol Chem, 1975 May 25, 250(10), 3874 - 7 The role of polyamines in the aminoacyl transfer ribonucleic acid synthetase reactions . Demonstration of the requirement for magnesium ion and a secondary stimulatory effect of spermine; Santi DV et al.; Spermine and related polyamines have been reported to substitute for Mg2+ in the aminoacylation of tRNA catalyzed by aminoacyl-tRNA synthetases, but not in the ATP-PP-i exchange reaction . Such observations have led some workers to propose that these reactions proceed via a concerted mechanism rather than the usual two-step mechanism involving an aminoacyladenylate intermediate . In an attempt to elucidate the mechanism of the spermine effect on acylation and exchange, both reactions were re-examined using isoleucyl-tRNA synthetase from Escherichia coli . In the absence of added Mg2+ untreated tRNA was acylated in the presence of spermine, but tRNA from which Mg2+ had been scrupulously removed was not . ATP-PP-i exchange was not observed when spermine was used in place of Mg2+; however, if tRNA possessing sequestered Mg2+ was added, the exchange reaction was observed . These data suggest that a primary effect of spermine is to displace bound Mg2+ from tRNA in quantities sufficient to promote both the ATP-PP-i exchange and esterification of tRNA . The previously reported stimulatory effects of polyamines on these reactions are believed to be artifacts due to Mg2+ contamination of tRNA . Providing trace levels of Mg2+ are present, spermine exerts a secondary stimulation of the rate of aminoacylation, the mechanism of which is unknown . The results presented refute arguments that these enzymes proceed by a concerted mechansim and support the intermediacy of aminoacyladenylates. J Biol Chem, 1975 May 25, 250(10), 3866 - 73 Kinetic demonstration of the intermediate role of aminoacyl-adenylate-enzyme in the formation of valyl transfer ribonucleic acid; Midelfort CF et al.; The question whether aminoacyl-tRNA synthetases act in a stepwise or in a concerted mechanism has been investigated kinetically with the valine enzyme of Escherichia coli, which had been used in previous studies by others who concluded that the physiological mechanism is concerted . An exchange between aminoacyl-tRNA and tRNA, dependent upon AMP, was studied . PP-i inhibits this exchange completely in the presence of Mg2+ and AMP but in the absence of added Mg2+ or with dAMP as the nucleotide the inhibition by PP-i is only partial; this is compatible with a stepwise, not a concerted, reaction . Exchange of isotopically labeled substrates in a system at chemical equilibrium also shows effects of substrate concentrations on rates in agreement with the predictions of a stepwise mechanism. J Biol Chem, 1975 May 25, 250(10), 3679 - 82 Differentiation between binding and transport of dansylgalactosides in Escherichia coli; Schuldiner S et al.; The results presented in this paper confirm and extend previous observations which indicate that fluorescent dansylgalactsodes bind to the beta-galactoside carrier protein but do not penetrate the cytoplasmic membrane . The conclusion is supported by the following observations . (a) Although 2'-(N-dansyl)aminoethyl-beta-D-thiogalactopyranoside and 2'-(N-dansyl)aminoethyl-beta-D-galactopyranoside are competitive inhibitors of lactose transport in intact cells of Escherichia coli and induce the in vitro synthesis of beta-galactosidase, they do not induce beta-galactosidase in vivo . (b) p-Chloromercuribenzenesulfonate does not cause efflux of lactose from the intravesicular pool, but causes rapid reversal of D-lactate-induced dansylgalactoside fluorescence . (c) Dansylgalactosides inhibit dilution-induced, carrier-mediated lactose efflux. Biochemistry, 1975 May 20, 14(10), 2043 - 50 Sequence holology between mitochondrial DNAs of different eukaryotes; Jakovcic S et al.; The sequence divergence of mitochondrial DNAs (mtDNA) from rat, mouse, guinea pig, monkey, and chicken has been examined by DNA-DNA hybridization . mtDNAs, isolated as closed circular molecules by propidium iodide-CsCl centrifugation, were labeled in vitro by use of Escherichia coli DNA polymerase I, and renatured (Tm-35 degrees) in the presence of a 2500-fold excess of heterologous mtDNA . Single-stranded and duples DNA were separated by hydroxylapatite chromatography . The thermal stability of heteroduplexes was compared to the homoduplex by thermal elution chromatography on hydroxylapatite columns . Heteroduplex fromation between the tritiated myDNAs and a 2500-fole excess of rar mtDNA were 70, 59, 37, and 22%, respectively, for mouse, guinea pig, monkey, and chicken . Similar results were obrained in reciprocal hybridizations where one of the other mtDNAs was present in excess . Considerable mismatching of sequences in all the heterohybrids was indicated by a 18-24 degrees depression in the te50 of the heteroduplexes compared with the homoduplex . There was no apparent change in heteroduplex formation when the concentration ratio of driving DNA in excess to {3H}mtDNA was varied between 1250 and 7500 . Furthermore, a second renaturation with excess driving DNA after completion of the first reaction resulted in no detectable augmenting of heteroduplex formation . Similar sequences appear to be conserved preferentially in different organisms, since the presence of two of fouf different heterologous mtDNAs in excess resulted in only moderate and nonadditive increases in heteroduplex formation . Evolutionary divergence of mtDNA sequences appears to have occurred at rates similar to that for unique sequences nuclear DNA. Biochemistry, 1975 May 20, 14(10), 2037 - 42 Sequence homology of the mitochondrial leucyl-tRNA cistron in different organisms; Jakovcic S et al.; Sequence divergence of the mitochondrial leucytl-tRNA cistron in several eukaryotes has been examined by RNA-DNA hybridized . Rat mitochondria Leucyl-tRNA was hybridized with rat, mouse, guinea pig, monkey, chicken, and yeast mitochondrial DNAs (mtDNA) immobilized onfilters . Hybridization was carried out in 50% formamide (Tm -12degrees) or in 20% fromamide (Tm -21degrees) . melting profiles of the hybrids were obtained for evaluation of the extent of base sequence micmatching . Under the more stringent hybridization conditions (50% formamide, Tm -12degrees), only mouse and quines pig mtDNAs hybridized with rat mitochondrial leucyl-tRNA . The Tm's of the heterohybrids were depressed by 2 and 9 degrees, respectively . Under less stringent hybridization conditions (Tm-21 degrees), monkey mtDNA also hybridized, and the Tm was depressed by about 15 degrees . Chicken and yeast mtDNAs did not form specific hybrids with rat mibochondrial leucyl-tRNA under these hybridization conditions . Mitochondrial leucyl-tRNA sequences in different eukaryotes appear to be conserved to a less extent than cytoplasmic rRNA, 5S RNA, or hemoglobin mRNA sequences. Biochemistry, 1975 May 20, 14(10), 2219 - 24 Nuclear magnetic resonance study of ligand binding to Mn-aspartate transcarbamylase; Fan S et al.; Aspartate transcarbamylase from Escherichia coli has been prepared with up to four of zinc ions replaced by manganese, and the effect of this substitution on the proton nuclear magnetic resonance properties of succinate bound to the catalytic site and of cytidine 5'-triphosphate bound to the regulatory site has been determined, The specific activity and allosteric properties of the Mn-substituted enzyme are essentially identical with those of the native enzyme . The longitudinal relaxation time, T1, of the succinate protons is shortened by the native enzyme and is shortened further by the Mn-substituted enzyme at both 100 and 220 MHz in D2O solutions of 0.02 M immidazole chloride (pH 7.0), 10 minus 3 M beta-mercaptoethanol, 0;2 mM ethylenediamenetetraacetic acid, and 2.5 mM carbamyl phosphate over a temperature range of 5 to 35 degrees . Under the same conditions, the transverse relaxation time, T2, of the succinate protons at 90 MHz is shortened to the same extent by native and Mn-substituted enzyme . The temperature dependence of the relaxation times indicates that the shortening of the transverse relaxation time is determened by the lifetime of bound succinate, whereas the further shortening of the longitudinal relaxation time by the Mn-substituted enzyme is due to dipolar relaxation, i.e . to the interaction between Mn and the succinate protons . The distance between the Mn and the protons of succinate bound to the enzyme can be calculated from the relaxation time measurements and is 15,3 A . The dipolar interaction correlation time which is needed for the calculation of this distance, was found to be 3.5 X 10 minus 9 sec from the frequency dependence of T1 . The transverse relaxation time of the C-6 proton of CTP is shortened to the same extent by both the native and Mn-substituted enzyme in D2O solutions of 0.02 M imidazole chloride (pH 7.0), 10 MINUS 3 M beta-mercaptoethanol, 0.2 mM ethylenediaminetetraacetic acid, and 2.5 mM carbamyl phosphate over the temperature 5-30 degrees . Since the temperature depencece of the relaxation time indicates the relaxation is not exchange limited, the manganese must be too distant from the bound CTP for an appreciable interaction to occur . This requires that the manganese be greater than 20A from the CTP . These results are used together with other available structural data to construct a schematic model for aspartate transcarbamylase. Biochemistry, 1975 May 20, 14(10), 2275 - 82 Zinc and magnesium content of alkaline phosphatase from Escherichia coli; Bosron WF et al.; Since alkaline phosphatase from Escherichia coli was first reported to contain 2.1 g-atoms of zinc and 0.8 g-aton of magnesium per molecular weight 80,000 (Plocke, D.J., Levinthal, D., and Vallee, B . L . (1962), Biochemistry 1, 373-378), the procedures for isolation and purification of the enzyme, as well as values for the protein molecular weight, specific absorptivity, and maximal activity, have changed repeatedly . Such variations have resulted in uncertainties concerning the molar metal content of this phosphatase . The present paper reviews the initial and recent results of metal analyses of alkaline phosphatase preparations in this laboratory and compares them with those obtained elsewhere, while simultaneously identifying some of the factors which have affected reports on the metal content of this enzyme . A purification procedure is described eliminating the features of all methods known to alter the metal content of phosphatase . In addition, the three isozymic forms, as well as preparations from four E . coli strains commonly employed for phosphatase isolation, were analyzed and compared. Biochim Biophys Acta, 1975 May 16, 390(3), 312 - 8 Difference in the action of ethyl and methyl methane sulfonates on DNA template activity for RNA synthesis in vitro; Guertin M et al.; RNA produced in vitro from alkylated T7 DNA has been characterized by polyacrylamide gel electrophoresis . Methylation of T7 DNA by methyl methane sulfonate reduces RNA chain length . In contrast, ethylation of T7 DNA by ethyl methane sulfonate, while reducing RNA synthesis to the same extent, does not alter chain length. N Engl J Med, 1975 May 15, 292(20), 1041 - 5 Enterotoxigenic Escherichia-coli-associated diarrheal disease in Apache children; Sack RB et al.; A search for intestinal enterotoxigenic Escherichia coli was made in 59 Apache children hospitalized with 64 episodes of acute diarrhea . Esch . coli isolates from acute-phase and convalescent-phase specimens of small-bowel fluid and stool were tested in three currently recognized models: the adult-rabbit ileal loop; infant rabbit; and the adrenal-cell assay . Enterotoxigenic strains were isolated from 10 children during acute diarrheal episodes (16 per cent); none were isolated from convalescent-phase specimens . None of 64 "enteropathogenic" serotypes of Esch . coli from 43 children with diarrhea, however, caused fluid production in the ileal-loop model . These results suggest that enterotoxigenic Esch . coli may be the cause of considerable diarrhea in this population and that the term "enteropathogenic" as applied to serotypes of Esch . coli needs to be redefined. Cancer Chemother Rep, 1975 May-Jun, 59(3), 611 - 20 Interaction of Rhodium(II) carboxylates with molecules of biologic importance; Bear JL et al.; Rhodium(II) acetate, propionate, and butyrate showed a considerable variation in their antitumor activity against Ehrlich ascites tumor cells in mice, with the butyrate complex being the most active . The three complexes markedly inhibited DNA synthesis of Ehrlich ascites tumor cells in vivo . Rhodium (II) butyrate was the most potent inhibitor followed by the propionate complex . One hour after administration, rhodium(II) propionate and butyrate induce more uridine-5-3H incorporation into RNA than is seen in the controls . Equilibrium dialysis studied showed that rhodium(II) acetate-1-14C binds to single stranded DNA, poly-A, ribonuclease A, and bovine serum albumin but not to highly polymerized native calf thymus DNA, poly-G, or poly-C . In these cases binding occurred at the two axial positions of rhodium(II) acetate to a nitrogen donor in the ligands . The formation constants of the rhodium(II) acetate and propionate complexes with 5'-adenosine monophosphate were determined . The rhodium(II) propionate complex was more stable . Sedimentation and viscosity measurements of poly-A and poly-A/rhodium(II) acetate complexes indicate a high degree of intramolecular crosslinking in the rhodium(II) acetate/poly-A complex . The rhodium(II) carboxylate complexes were also found to be potent inhibitors of purified DNA polymerase I and RNA polymerase from Escherichia coli. Klin Wochenschr, 1975 May 1, 53(9), 441 - 3 {Cholestatic jaundice following disseminated intravascular coagulation ("shock-liver") (author's transl)}; Kunzer W et al.; Recently we gained increasing evidence of the fact that cholostatic syndromes in young infants are frequently associated with preceeding shock and disseminated intravascular coagulation . This is illustrated by the case of a 4 weeks-old male infant with urosepticemia due to E . coli, which was successfully treated with additional streptokinase . Therefore, in the age-group of early infancy we have to pay attention to the liver as a potential shock-organ similar to the well known shock organs such as kidneys, lungs, skin and brain. J Biol Chem, 1975 May 10, 250(9), 3352 - 8 Kinetic and equilibrium studies on the activation of Escherichia coli K12 tryptophanase by pyridoxal 5'-phosphate and monovalent cations; Hogberg-Raibaud A et al.; An improved purification of Escherichia coli K12 tryptophanase is presented . It is shown that the apoenzyme crystals, oxidized by exposure to air, can be reactivated by treatment with a reducing agent . The titration of sulfhydryl groups shows that four --SH groups are exposed and two are masked per protomer . The influence of two effectors, monovalent cations and the coenzyme pyridoxal 5'-phosphate, on the reactivity of --SH groups and the enzymatic activity was investigated . The --SH groups react more slowly in holo- than in apoenzyme in the presence of potassium ions . If these ions are replaced by sodium ions, the reactivity becomes the same . Potassium and ammonium ions, both activators, give sigmoidal activation curves . The sodium ion is a Michaelian inhibitor of potassium activation . The binding of pyridoxal 5'-phosphate was examined by kinetics and at equilibrium . The kinetics are shown to be very slow; the rate constants of the forward and reverse reactions have been measured . The binding equilibrium, examined with 3H-labeled pyridoxal 5'-phosphate, gives one site per protomer with a K-D value of (3.2 plus or minus 0.8) times 10-7 M . The K-m for pyridoxal-P was determined by activity measurements . The binding equilibrium is attained after several hours, giving a value of 4.2 times 10-7 M, being nearly identical with the dissociation constant and 5 times smaller than previously reported. J Biol Chem, 1975 May 10, 250(9), 3545 - 51 Purification and properties of guanosine triphosphate cyclohydrolase II from Escherichia coli; Foor F et al.; An enzyme that uses GTP as substrate for the formation in stoichiometric quantities of formate, inorganic pyrophosphate, and 2,5-diamino-6-hydroxy-4-(ribosylamino)pyrimidine-5'-phosphate has been purified 2200-fold from extracts of Escherichia coli B . This enzyme is named GTP cyclohydrolase II to distinguish it from a previously studied E . coli enzyme, named GTP cyclohydrolase (and called GTP cyclohydrolase I in this paper), that catalyzes the first of a series of enzymatic reactions leading to the biosynthesis of the pteridine portion of folic acid (Burg, A . W., and Brown, G . M . (1968) J . Biol . Chem . 243, 2349-2358) . Some of the properties of GTP cyclohydrolase II are: (a) divalent cations are required for activity (Mg2+ is most effective); (b) its molecular weight, estimated by filtration on Sephadex G-200, is 44,000; (c) the K-m for GTP is 41 mum; (d) its pH optimum is 8.5; and (e) its activity is inhibited by inorganic pyrophosphate, one of the products of the reaction . Compounds not used as substrate are: GDP, GMP, guanosine, dGTP, ATP, ITP, and XTP . Properties a, b, c, and e (above), as well as the nature of the products, distinguish this enzyme from GTP cyclohydrolase I . Since GTP cyclohydrolase II apparently is not concerned with the biosynthesis of folic acid, the possible physiological role of this enzyme in the biosynthesis of riboflavin is considered in the light of the present investigations and the previously published work on riboflavin biosynthesis by other investigators. J Biol Chem, 1975 May 10, 250(9), 3505 - 9 Use of the sodium borohydride reduction technique to identify a gamma-glutamyl phosphate intermediary in the Escherichia coli glutamine synthetase reaction; Todhunter JA et al.; Incubation of unadenylylated Escherichia coli glutamine synthetase with ATP, L-{14C}glutamate and metal ion results in the formation of gamma-glutamyl-P which can under appropriate conditions be reduced by sodium borohydride . The acyl-P compound is formed catalytically as judged by the quantity of radioactive alpha-amino-delta-hydroxyvalerate produced compared to the concentration of enzyme subunits . Formation of the glutamyl-P compound occurs in the presence of magnesium or manganous ions, and the relation of this apparent lack of metal ion specificity with regard to the highly specific Mg2+-supported biosynthetic activity of the unadenylylated form is discussed. J Biol Chem, 1975 May 10, 250(9), 3261 - 6 Enhancement of the glutaminase activity of carbamyl phosphate synthetase by alterations in the interaction between the heavy and light subunits; Wellner VP et al.; Glutamine-dependent carbamyl phosphate synthetase (from Escherichia coli) was previously shown to be composed of a light subunit (molecular weight similar to 42,000) which has the binding site for glutamine and a heavy subunit (molecular weight similar to 130,000) which has binding sites for the other reactants and allosteric effectors . The subunits may be separated with retention of catalytic activities; only the separated light subunit exhibits glutaminase activity . The previous finding that storage of the native enzyme at pH 9 at 0 degrees increased its glutaminase activity by about 25-fold was further investigated; such storage markedly decreased the glutamine- and ammonia-dependent synthetase activities of the enzyme . Treatment of the enzyme with p-hydroxymercuribenzoate led to transient increase of glutaminase activity followed by inhibition . When the enzyme was treated with N-ethylmaleimide or with 5,5'-dithiobis-(2-nitrobenzoate), the glutaminase activity was increased by about 250-fold with concomitant loss of synthetase activities . The enhancement of glutaminase produced by storage of the enzyme at pH 9 was associated with intermolecular disulfide bond formation and aggregation of the enzyme . Aggregation also was observed after extensive treatment of the enzyme with 5,5'-dithiobis-(2-nitrobenzoate) or N-ethylmaleimide . However, a moderate increase of glutaminase activity (about 30-fold) was observed without aggregation under conditions in which one sulfhydryl group on the light subunit reacted with either reagent . The findings suggest that the increased glutaminase activities observed here are associated with structural changes in the enzyme in which the intersubunit relationship is altered so as to uncouple the catalytic functions of the enzyme and to facilitate access of water to the glutamine binding site on the light subunit. J Biol Chem, 1975 May 10, 250(9), 3243 - 53 The nucleotide sequences of the two glutamine transfer ribonucleic acids from Escherichia coli; Yaniv M et al.; The nucleotide sequences of the two glutamine tRNA species in Escherichia coli K12 have been determined . Sufficient data was obtained to order unambiguously the products of complete RNase digestion of tRNA2Gln, and all but one oligonucleotide from tRNA1Gln . The sequence of tRNA1Gln was established by analogy with tRNA1Gln, as the two tRNAs are very similar, differing by only 7 residues out of 75 . tRNA1Gln has the anticodon NUG, where N is a modified nucleotide which is likely to be a derivative of 2-thiouridine, and is specific for the codon CAA . tRNA1Gln has the anticodon CUG, and is specific for the codon CAG (Folk, W . R., and Yaniv, M . (1972) Nature 237, 165) . The complete sequences of the tRNAGln species are: See journal for formula (Unique residues are enclosed in parentheses, with the residue in tRNA1Gln above that in tRNA2Gln.). Eur J Biochem, 1975 May 6, 53(2), 605 - 13 Comparative effect of heparin on RNA synthesis of isolated rat-liver nucleoli and purified RNA polymerase A; Ferencz A et al.; The polyanion heparin has been employed to study the interaction of rat liver DNA-dependent RNA polymerase A and its template under various conditions . Heparin very efficiently inhibits polymerase molecules, which are not bound to DNA or are associated with the template in a loose, i.e . non-specific fashion . Purified nucleoli, isloated from rat liver nuclei, contain RNA polymerase A in abundant quantities of which only a portion is bound in a transcriptional complex . Excess enzyme, which is contained in the nucleolus in a quasi free form, can be transferred to an exogenously added template and can be completely inhibited by the prior addition of heparin . The enzyme contained in a transcriptional complex, however, initiated in vivo and completing these RNA chains in vitro, is fully resistant to heparin . In contrast to these results it has been found that RNA polymerase A extracted from nuclei and purified by various chromatographic steps does not form heparin-resistant complexes, even after the enzyme has been bound to the DNA template . Moreover it has been found that purified RNA polymerase A transcribes truly native DNA extremely poorly, indicating that the enzyme is highly deficient in the act of initiation on duplex DNA . It is therefore questionable whether the interaction of the purified enzyme and isolated DNA represents binding to true initiation complexes as is observed in the intact nucleolus. Eur J Biochem, 1975 May 6, 53(2), 599 - 603 The effect of tRNA derivatives bound with natural or synthetic mRNA on the interaction of Escherichia coli ribosomes with colicin E3; Kaufmann Y et al.; Ribosomal binding complexes directed by poly(U) or T4 mRNA were formed with aminoacyl-tRNA or its derivatives bound to predominantly the P or A binding site . The defined binding complexes were reacted with colicin E3 and the reaction was assessed by the ability of the complexes to proceed with polypeptide synthesis . The results indicated that only one of the four complexes tested was completely resistant to colicin E3-induced inactivation: that of Phe-tRNA bound in the presence of poly(U) to the A-site . The poly(U) directed complex of AcPhe-tRNA and the T4-mRNA-directed complex at the A-site appeared slightly resistant, while the T4 mRNA initiation complex was inactivated by colicin E3 in a manner similar to non-complexed ribosomes . Colicin E3 added to ribosomes after protein synthesis had been initiated affected the subsequent polymerization in a manner corresponding to the response of the binding complexes . Thus, poly(U)-translating ribosomes were less affected than ribosomes translating the viral mRNA . The vulnerability of natural-mRNA-directed binding complexes to inactivation by colicin E3 is in accord with the mode of inactivation by the colicin in vivo. Eur J Biochem, 1975 May 6, 53(2), 419 - 27 Glucose catabolite repression in Escherichia coli K12 mutants defective in methyl-alpha-d-glucoside transport; Bourd GI et al.; 1 . Two spontaneous Escherichia coli K12 mutants resistant to glucose catabolite repression were isolated using minimal agar plates with methyl alpha-D-glucoside . Mutants grow well on glucose and mannitol . 2 . Glucose does not inhibit the inducible enzyme synthesis in isolated mutants: mutant cell (in contrast to parent cells) produce high levels of beta-galactosidase and L-tryptophanase under the conditions of glucose catabolite repression . 3 . The isolated mutants are negative in methyl-alpha-D-glucoside transport; glucose uptake is not severely damaged . But the mutants (named tgl, transport of glucose) retained the ability to phosphorylate methyl alpha-D-glucoside in vitro at the expense of phosphoenolpyruvate . 4 . The tgl mutation is cotransduced with purB and pyrC markers, i.e . locates near 24 min of the E . coli chromosome map . 5 . It is thought that E . coli cells possess two glucose transport systems . The first one is represented by the glucose-specific enzyme II of the phosphoenolpyruvate-dependent phosphotransferase system . The second glucose transport system (coded for tgl gene) functions as permease and possesses high affinity to methyl alpha-D-glucoside . The integrity of glucose permease determine the sensitivity of the cell to glucose catabolite repression. Biochim Biophys Acta, 1975 May 6, 389(2), 358 - 69 Lipid phase transitions in cytoplasmic and outer membranes of Escherichia coli; Overath P et al.; The cytoplasmic and outer membranes containing either trans-delta-9-octadecenoate, trans-delta-9-hexadecenoate or cis-delta-9-octadecenoate as predominant unsaturated fatty acid residues in the phospholipids were prepared from a fatty acid auxotroph, Escherichia coli strain K1062 . Order-disorder transitions of the phospholipids were revealed in both fractions of the cell envelope by fluorescent probing or wide angle X-ray diffraction . The mid-transition temperatures, Tt, and the range of the transition, delta-T, are similar in the outer and cytoplasmic membrane . Relative to the corresponding extracted lipids, 60-80% of the hydrocarbon chains take part in the transition in the cytoplasmic membrane whereas in the outer membrane only 25-40% of the chains become ordered . The results suggest that in the outer membrane part of the lipids form fluid domains in the form of mono- and/or bilayers. Biochim Biophys Acta, 1975 May 6, 389(2), 236 - 50 Membrane reconstitution in chl-r mutants of Escherichia coli K 12 . IX . Part played by phospholipids in the complementation process; Azoulay E et al.; The supernatant extracts of the chl A and chl B mutants of Escherichia coli K 12, the phospholipids of which are labeled by growth in 32 P or {2- 3H}glycerol media, contain 20 times more radioactivity than the supernatant extract of the wild-type strain grown under the same conditions . We have observed that, after complementation, 80% of the radioactivity previously contained by Extracts A and B is incorporated into reconstituted particles . The chromatography of 3H-labeled Extract B on DEAE-cellulose and followed by gel filtration of radioactive fractions on Sephadex G-200 has shown that the phospholipids of Extract B are only bound to soluble proteins and not to fragments of membranes; it can be assumed that they have been solubilized in the form of a lipid-protein complex by cell breakage . When Extracts A and B are treated by phospholipase C (phosphatidylcholine cholinephosphohydrolase, EC 3.1.4.3) before being mixed together, an inhibition of the reconstitution of nitrate reductase activity which is proportional to the phospholipase C concentration and the length of treatment is observed . The analysis of lipids and phospholipids of particles (Peak I, Peak II and Peak III) formed during complementation and reconstituted nitrate reductase shows that their phospholipid contents (phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and phosphatidylserine) and especially that of Peak II (d equals 1.18) are closely related to that of native particles from the wild-type strain . These results allow one to propose a hypothesis explaining the mechanism involved in complementation. Biochim Biophys Acta, 1975 May 6, 389(2), 219 - 35 Membrane reconstitution in chl-r mutants of Escherichia coli K 12 . VIII . Purification and properties of the FA factor, the product of the chl B gene; Riviere C et al.; The isolation and purification of the product of the chl B gene of Escherichia coli K 12 from the chl A mutant have been attempted . The purified protein gives a single band in 10% sodium dodecylsulfate/polyacrylamide gel electrophoresis . The molecular weight is estimated to be 35 000 . This protein, that we have named "FA factor", does not contain any lipid, has a strong tendency to lose its activity by polymerizing but can be kept in an active state when stored in buffer containing NaCl . The addition of purified FA protein to a soluble extract from the chl B mutant strain grown under anaerobiosis in the presence of nitrate initiates the "complementation reaction", i.e . the reconstitution of the nitrate reductase activity and the formation of particulate material similar to the native membrane with respect to the structure and enzymatic function . FA protein acts both on the rate of reconstitution and on the total amount of reconstituted enzyme . The complementation leads to the reconstitution of nonsedimentable nitrate reductase and to the formation of three types of particles of different buoyant densities (1.10, 1.18 and 1.23) the two lightest of which contain nitrate reductase . It is shown that FA factor is incorporated only into the particles of intermediate density . In vivo, this factor is located in the native membranes of chl A, chl C, chl D and wild-type strains, whatever the growth conditions, aerobiosis or anaerobiosis, and in the presence or absence of nitrate . Protein FA can be released from either of these membranes (native or reconstituted) by removing Mg-2+ or by subjecting Kaback's vesicles to mechanical treatments; in the case of 1.18-reconstituted particles and wild-type membranes, the release of FA protein does not exert any effect on the level of the nitrate reductase activity. Biochemistry, 1975 May 6, 14(9), 1869 - 76 Conformations and structural transitions in polydeoxynucleotides; Pilet J et al.; Polydeoxynucleotides of different base sequence, the alternating poly{d(A-T)}-poly{d(A-T)}, crab satellite DNA, on the one hand, and double-stranded homopolymer complexes poly{d(A)}-poly{d(T)}, poly{d(I)}-poly{d(C)}, on the other, display significant differences in their conformation and conformational transitions . Infrared linear dichroism investigations indicate that the alternating poly{d(A-T)}-poly{d(A-T)}, enzymatically synthesized, adopts a lower humidity a well-expressed A* form in which stability is relatively small,i.e., restricted to limited relative humidity . This A form is characterized by the orientation of the bisector of the phosphate OPO group at 34 degrees with respect to the helical axis, which is slightly lower than that of DNA . In contrast, for the homopolynucleotide double-stranded complex poly(dA)-poly(dT) and also for poly(dI)-poly(dC), the B yields A conformational change is not observed . Instead poly(dA)-poly(dT) exists at lower humidity in a stable modified B form . Thus the present results indicate that homo(dA)-homo(dT) double-stranded sequences prevent the B yields A structural transition . All AT-containing polydeoxynucleotides and crab satellite DNA adopt a high humidity a modified B form characterized by the orientation of the bisector of the phosphate group OPO at 64 degrees with respect to the helical axis which is significantly lower than 68-74 degrees observed in DNAs . The base pairing geometry in poly(dA)-poly(dT), poly{d(A-T)}-poly{d(A-T)}, and also in poly(dI)-poly(dC) is apparently a Watson and Crick type . Thus the observed differences in conformation are not due to different base pairing scheme . It is suggested that in DNAs of high AT content the presence of homo(dT)-homo(dA) sequences and the relatively low stability of the A form of d(A-T) alternating sequences may inhibit the change to the A form . A possible role of these sequences in DNA recognition by protein is suggested. Biochemistry, 1975 May 6, 14(9), 1859 - 66 Evidence for fidelity of chromatin reconstitution; Stein GS et al.; Several lines of evidence are presented which support the contention that chromatin may be dissociated, fractionated, and reconstituted without altering the compositional, structural, or transcriptional integrity of the genome . The similar compositions of native and reconstituted chromatins are suggested by the absence of significant differences in their protein/DNA ratios and in the polyacrylamide gel electrophoretic profiles of their histones and nonhistone chromosomal proteins . Criteria for fidelity of genome structure in reconstituted chromatin include binding of reporter molecules with specificity for the minor groove of DNA, binding of histones, number of sites available for addition of nucleotides, and circular dichroism spectra . When the transcriptional activities of native and reconstituted chromatins were compared under conditions where reinitiation is prohibited, significant changes were not observed . Taken together, the present results strongly suggest, but do not conclusively establish, fidelity of chromatin reconstitution. Biochemistry, 1975 May 6, 14(9), 1805 - 14 A comparative study of the 50S ribosomal subunit and several 50S subparticles in EF-T-and EF-G-dependent activities; Sander G et al.; A series of ribosomal subparticles derived from the 50S subunit has been studied and compared in EF-T- and EF-G-dependent reactions . Three different 50S cores were prepared by CsC1 isophycnic centrifugation and one by NH(4)Cl-ethanol extractionm the 50S CsCl core a had lost proteins L1, L7, L8, L10, L12, L16, L25, L33, and some L6 and L11 . The 50S CsCl core b additionally lacked protein L6, and 50S CsCl core c also lacked protein L5, L15, L18, L27, L28, L30, and most of L9, L14, L19, and L21 . The 50S NH(4)Cl-ethanol core had lost up to 90 percent of proteins L7, L12 and 30-60 percent of proteins L8, L10, and L29 . The 50S CsCl core a had much reduced activity in EF-G and none in EF-T GTPase reactions while 50S CsCl cores b and c were inactive . Addition of proteins L7, L12 restored the activity for both the EF-T- and EF-G-dependent GTPase with all of the three 50S CsCl cores, increasing stepwise from core c to core a; The 50S NH(4)Cl-ethanol core was partially active in the EF-G GTPase over the 2-30 mM MG-2+ range tested, while EF-T only showed some activity inthe upper portion of this range... Biochemistry, 1975 May 6, 14(9), 1980 - 9 Regulation of Escherichia coli glutamine synthetase . Evidence for the action of some feedback modifiers at the active site of the unadenylylated enzyme; Dahlquist FW et al.; The interaction of unadenylylated form of Escherichia coli glutamine synthetase with several substrates and effectors has been examined by magnetic resonance techniques . These studies show that two manganese ions bind per enzyme subunit . From the dramatic line broadening observed in the alanine spectra in the presence of manganese and enzyme, it is concluded that the binding of alanine occurs at a site nearer one of the two manganese sites . Electron spin resonance (ESR) titration experiments suggest apparent dissociation constants of 20 and 120 muM for manganese to these sites in the presence of 1.0 mM magnesium ion . The manganese concentration dependence of the broadening of alanine suggests an affinity of 30 muM for the manganese closest to the alanine binding site . This suggests that alanine binds closer to the more tightly bound manganese ion . Glutamate appears to displace the alanine and also appears to bind close to the strongly bound manganese ion . It is proposed that alanine and glutamine bind competitively and in the same site . The binding of alanine and ATP is shown to thermodynamically interact such that the presence of one ligand increases the affinity of the enzyme for the other ligand . The presence of ATP dramatically sharpens the alanine line width when manganese and glutamine synthetase are present . Addition of ADP or phosphate alone has little effect on the alanine line width but the addition of both ADP and phosphate shows the same dramatic sharpening as the addition of ATP alone, suggesting an induced fit conformational change in the enzyme induced by ATP or by both ADP and phosphate . A binding scheme is proposed in which all feedback inhibitors of the enzyme bind in a competitive fashion with substrates. Biochim Biophys Acta, 1975 May 6, 389(2), 370 - 9 Requirement of heat and metabolic energy for the expression of inhibitory action of colicin K; Okamoto K; Escherichia coli B, induced for beta-galactoside permease, can accumulate thio-methyl-beta-galactoside in the cell even at 0 degrees D . At this temperature, cells adsorb colicin K but the adsorbed colicin does not inhibit thiomethyl-beta-galactoside uptake . Inhibition by colicin K is, however, seen at 0 degrees C after exposure of the colicin K-cell complex to a high temperature: a greater degree of inhibition occurs with increasing temperature or duration or exposure . There is a transition point at around 21 degrees C in Arrhenius plots of this colicin K activation reaction . If inhibitors of energy yielding reactions are present during the heat treatment, the inhibitory action of colicin K (as measured by thiomethyl-beta-galactoside uptake after returning the colicin K-cell complex to 0 degrees C and removal of the inhibitors) is prevented . These results indicate that adsorbed colicin K is converted into the active state only in the presence of metabolic energy and that cell surface fluidity appears to be concerned in this process. Biochemistry, 1975 May 6, 14(9), 1956 - 64 2'-O-methylated oligonucleotides in ribosomal 18S and 28S RNA of a mouse hepatoma, MH 134; Hashimoto S et al.; Simple two-dimensional thin-layer chromatography was found to be useful for the separation of sugar methylated dinucleotides in RNA . Of the 16 possible sequences of the type Nm-Np, 15 were separated and all the sequences were determined . In a mouse hepatoma, MH 134, the levels of the sugar methylation in the 18S and 28S RNA molecules were 17-18 and 11-12 per 1000 nucleotides, respectively . Thus, 18s RNA contained approximately 35 2'-O-methylated dinucleotides and 28S RNA approximately 60 2'-O-methylated dinucleotides . The pattern of distribution was also distinct between these two molecules . Two 2'-O-methylated trinucleotides were identified in the 28S RNA with the sequences Um-Gm-Up and Um-Gm-psip . A unique 2'-O-methylated tetranucleotide was present also in the 28S RNA, the sequence of which was Am-Gm-Cm-Ap . The 5'-terminal nucleotides of both 18S and 28S RNA were obtained as nucleoside 3',5'-diphosphates (pNp) in the trinucleotide fraction of the RNase T2 digest . The 5'-termimi of 18S and 28S RNA were pUp and pCp, respectively, and found to be almost homogeneous. Biochemistry, 1975 May 6, 14(9), 1866 - 8 The role of superoxide radical in the autoxidation of cytochrome c; Cassell RH et al.; The net rate of autoxidation of ferrocytochrome c was decreased by ferricytochrome c . Superoxide dismutase accelerated this autoxidation to a limit and overcame the inhibitory effect of ferricytochrome c . This was the case whether the autoxidationwas observed in the presence or in the absence of denaturants, such as alcohols orurea, and whether the superoxide dismutase used was the Cu-2+-Zn-2+ enzyme from bovine erythrocytes or the Mn-3+-enzyme from Escherichia coli . It can be deduced that the autoxidation of ferrocytochrome c, under a variety of conditions, geenerates O2 minus which can then dismute to H202 + O2 or can reduce ferricytochrome c back to ferrocytochrome c . Superoxide dismutase, by accelerating the dismutation of O2 minus, prevents the back reaction and thus exposes the true rate of reaction of ferrocytochrome c with molecular oxygen. Biochemistry, 1975 May 6, 14(9), 1821 - 5 Different cyclic adenosine 3',5'-monophosphate requirements for induction of beta-galactosidase and tryptophanase . Effect of osmotic pressure on intracellular cyclic adenosine 3,5-monophosphate concentrations; Piovant M et al.; In this study we have tried to answer the following questions: (1) is it possible for different catabolite-repressible genes, although submitted to the same control, to be expressed selectively depending upon the growth conditions, and (2) what is the effect of increasing the osmolarity of the medium on the intracellular level of cAMP? Two conditions were found to cause a continuous variation of intracellular cAMP levels during growth . With different strains, higher cAMP levels are required for induction of the tryptophanase gene than one required for induction of the lactose operon . cAMP has been provided externally in adenyl cyclase minus cells of a mutant that has been made permeable by EDTA treatment . Although external cAMP concentrations, 10 times higher than the usual intracellular levels, are required for induction of beta-galactosidase and tryptophanase, the difference of requirements of cAMP is maintained . An increase in the osmolarity of the medium by sucrose addition causes a fourfold decrease in the intracellular cAMP level . As a consequence this prevents the induction of tryptophanase whereas beta-galactosidase is still inducible . After pulse induction, a difference in the kinetics of expression of the tryptophanase and beta-galactosidase genes was found . Its relationship with the previous results is discussed. Biochim Biophys Acta, 1975 May 6, 389(2), 203 - 18 Membrane reconstitution in chl-r mutants of Escherichia coli K 12 . VII . Purification of the soluble ATPase of supernatant extracts and kinetics of incorporation into reconstituted particles; Giordano G et al.; Membrane-bound ATPase (EC 3.6.1.3) of Escherichia coli K 12 is released in a soluble form by the mechanical treatments applied to the cells in order to break them . The purification of the soluble enzyme is described . The purified protein gives a single band in 7.5% polyacrylamide gel electrophoresis . The molecular weight is estimated to be 350 000 . The enzyme is cold-labile, Mg-2+ dependent, insensitive to inhibition by N, N'-dicyclohexylcarbodiimide and specific for ATP and ADP . Membranes depleted of their ATPase activity by dilution in a buffer of low ionic strength and without Mg-2+ are able to incorporate the purified ATPase only in the presence of 2-6 mM Mg-2+ . ATPase binds to particles formed by complementation between supernatant extracts of chl A and chl B mutants . There are three kinds of particles of different buoyant densities (1.10, 1.18 and 1.23); ATPase binds only to the 1.10 and 1.18 particles . The kinetics of incorporation have been studied . ATPase begins to be incorporated into the 1.10 particles after 10 min of incubation up to a maximum at 20 min: from 30 min, ATPase is incorporated only into 1.18 particles and the amount of incorporated ATPase increased in proportion with the peak of 1.18 particles . These kinetics have a hyperbolic pattern . In order to explain the mechanism of assembly involved in complementation, two hypotheses are proposed. Nucleic Acids Res, 1975 May 5, 2(5), 735 - 44 Stimulation of transcription of mouse kidney chromatin by sulfated polysaccharides; Warnick CT et al.; The sulfated polysaccharides polydextran sulfate (PDS) and heparin stimulate in vitro transcription of mouse kidney chromatin by E . coli RNA polymerase by about 100 and 40 fold respectively . Heparin which has been N-desulfated and N-acetylated stimulates only 13 fold . Chondroitin sulfate B and heparitin sulfate do not stimulate transcription under similar conditions . PDS inhibits transcription of deproteinized chromatin . Therefore, the stimulation with chromatin is due to interaction with the chromatin and not the polymerase . Polydextran sulfate has no effect on the size of the RNA that is made either under conditions in which the enzyme can reinitiate or under conditions in which reinitiation is blocked . If reinitiation of the enzyme is blocked, the time required to complete the synthesis of the RNA is the same whether or not the enzyme is stimulated by PDS . These observations indicate that sulfated polysaccharides stimulate transcription by making available new RNA polymerase binding sites on the chromatin. Nucleic Acids Res, 1975 May 5, 2(5), 723 - 33 A study of the interaction of histones with DNA using isopycnic centrifugation in metrizamide gradients; Rickwood D et al.; Isopycnic sedimentation in metrizamide gradients has shown that mouse-liver histones bind co-operatively to both homologous and bacterial DNA's . However, at low input ratios of histone to DNA, two types of stable complex are formed, depending on the histone concentration . One complex contains half as much histone as DNA while the other contains approximately equal amounts of histone and DNA . At high input ratios of histone to DNA extra histone is bound giving complexes containing up to twice as much histone as DNA . Poly-L-lysine and protamine were also found to bind co-operatively to DNA. Nucleic Acids Res, 1975 May 5, 2(5), 683 - 90 The preparation of 5-cyanouracil and 5-cyano-2'-deoxyuridine from the corresponding 5-iodo derivative and cuprous cyanide; Bleackley RC et al.; 5-Cyanouracil has been prepared in high yield from cuprous cyanide and 5-iodouracil . The deoxynucleoside has been similarly prepared form 5-iodo-2'-deoxyuridine and this has enabled these compounds to be labelled with (14-C) cyanide . Attempts have been made to incorporate 5-cyanouracil into Escherichia coli 15T and into Mycoplasma mycoides var . capri DNA under conditions in which several other 5-substituted uracils have been incorporated, but without success . Similarly 5-cyano-2'-deoxyuridine could not be incorporated into the DNA of T3 phage under conditions in which 5-bromo-2'-deoxyuridine is easily incorporated . These results suggest that the criteria for a 5-substituted uracil to be incorporated into DNA in vivo depends on some factor other than the size of the substituent. Nucleic Acids Res, 1975 May 5, 2(5), 635 - 46 Enzymic in vitro repair and chemical nature of DNA chain breaks induced by incorporated phosphorus-32P decay; Fodor I et al.; In vitro repair of single strand breaks in T4 and phage DNA caused by 32p decay was studied . Zone centrifugation procedure showed that polynucleotide kinase, ligase enzyme system failed to repair 32P-damages . It was found that damaged DNA contained gaps and could be repaired by DNA-polymerase I, polynucleotide ligase treatment. Arch Microbiol, 1975 May 5, 103(3), 251 - 7 On the structure of the peptidoglycan of cell walls from Myxobacter AL-1 (myxobacterales); Harcke E et al.; Basically the peptidoglycan of Myxobater AL-1 consists of alternating beta-1,4-linked N-acetylglucosamic-N-acetylmuramic acid chains . After splitting the aminosugar backbone with a specific algal enzyme three subunits arise: a monomer, a dimer and a timer . Investigation of the monomer with specific enzymes and comparison of the degradation products to standards derived from other bacterial peptidoglycans suggest the following structure of the monomer peptide: L-alanyl-D-glutamic-L-meso-diaminopimelic-D-alanine . A D-alanyl-D-meso-diaminopimelic acid bond is the bridgebond between the peptides of the subunits. Nucleic Acids Res, 1975 May 5, 2(5), 613 - 24 Enzymatic synthesis of oligonucleotides of defined sequence . Addition of short blocks of nucleotide residues to oligonucleotide primers; Gillam S et al.; Polynucleotide phosphorylase from Escherichia coli can be used to catalyse the addition of short tracts of deoxyadenylate residues to the 3'-termini of deoxyribooligonucleotides of the type pdAn-dN (where dN = dC, dT or dG) using dADP as donor . Similarly, the enzyme can also be used to catalyse the addition of short tracts of adenylate residues to the 3'-termini of ribooligonucleotides of the type An-N (where N = C, U or G) using ADP as donor . In the ribooligonucleotide series, phosphorolytic cleavage of the primer oligonucleotides is significant and results in the concommitant production of oligoadenylates lacking the N residue . Oligomers of the same length, with and without the residue N, were readily separated by thermal elution from cellulose-pdT9 columns . This latter procedure therefore provides a simple method for purification of the oligoadenylates containing an internal base substitution and it also provides a convenient assay for oligonucleotide phosphorolysis. Nucleic Acids Res, 1975 May 5, 2(5), 691 - 8 Maturation of a hypermodified nucleoside in transfer RNA; Agris PF et al.; E . coli C6 rel- met- cys- was cultured in a fully supplemented medium and in media lacking cysteine or methionine . tRNA isolated from the three cultures containted, respectively, a normal complement of modified nucleosides; a deficiency in thiolated nucleosides and a deficiency in methylated nucleosides . Both sulfur-deficient tRNA and methyl-deficient tRNA contained large amounts of N-6- (delta-2-isopentenyl) adenosine and small amounts of the 2-methylthio derivative . Methyl-deficient tRNA contained, in addition a large amount of a cytokinin active, differently modified nucleoside that is believed to be a sulfur derivative of N6-(delta-2-isopentenyl) adenosine . The structure of this compound is unknown . When methly-deficient tRNA and the precusor the tRNA-Tyr su3-+ A25 were enzymatically methylated in vitro, methyl groups were incorporated into derivatives of isopentenyladenosine . These results indicate that the biosynthesis of the 2-methylthio derivative of isopentenyladenosine may occur in a sequential manner, i.e., thiolation of isopentenyladenosine followed by methylation. Mol Biol (Mosk), 1975 May-Jun, 9(3), 426 - 34 {Possibility of internal organization of RNA and proteins in ribosomal subparticles . A structural model of Escherichia coli 30S ribosomal subparticle}; Potapov AP; The hypothetic model of reciprocal spatial arrangement of 18 from 21 proteins in the E . coli 30S ribosomal subparticle is suggested . The model is based on conception of the 16S R-A molecule macrostrand which is the right superhelix in the subparticle composition . Macrohelix's biopolarity against single-stranded sites of RNA and its small width result in that proteins binding with single-stranded RNA organized in chain, one-number sequence . The double helixes uniting the corresponding one single-stranded sites of RNA play the role of rigid transmission between them . So, in the course of subparticles reconstruction from RNA and proteins the spatially uncoupled proteins can interact without its direct contact . The model takes into consideration the vast amount of information. Am J Physiol, 1975 May, 228(5), 1479 - 82 Prostaglandin F and E levels during endotoxin-induced pulmonary hypertension in calves; Anderson FL et al.; Prostaglandin F and E (PGF and PGE) concentrations in sequential blood samples obtained simultaneously from the pulmonary artery (PA) and pulmonary vein (PV) during endotoxin-induced pulmonary hypertension in calves were determined by radioimmunoassay . Three groups of calves were studied . In nine control calves in which no endotoxin was given PA pressure and PGF and PGE concentrations in four pairs of samples taken at 0, 5, 15, and 45 min did not change . In 17 calves given 1 mg E . coli endotoxin, PGF concentrations were increased significantly in the PV and to a lesser degree in the PA in the 15-and 45-min samples . The increased PGF concentration in the 15-min sample corresponded to an increased PA pressure of 74 plus or minus 4 mmHg (mean plus or minus SE) . In three of the endotoxin-treated calves studied a second time and three separate calves indomethacin pretreatment completely blocked the hemodynamic effect of endotoxin as well as PGF release . PGE concentrations did not change in either group . These data suggest that endotoxin-induced pulmonary hypertension may be mediated by PGF, a known pulmonary pressor agent in the bovine, and that blockade of this effect by indomethacin may be due to inhibition of prostaglandin synthesis and/or release. Proc Natl Acad Sci U S A, 1975 May, 72(5), 1734 - 8 Repetitive DNA replication of the incomplete genomes of phage T4 petite particles; Kozinski AW et al.; The genomes of petite T4 phage particles presumably cannot circularize because they are deficient for a significant terminal segment and hence not terminally redundant like normal T4 genomes . Combined density- and 32P-labeling shows that the majority of such deficient DNA molecules can nevertheless replicate their entire length . Furthermore, the density-shift technique shows that replicated parental strands can exchange their partners for new light strands, indicating that noncircularized T4 DNA molecules replicate repeatedly . When taken together with previously published data, these results indicate that T4 replication is bidirectional from multiple, genetically fixed points of origin . Rolling circle models can, therefore, not be considered as an essential mechanism for the early rounds of T4 replication. J Biochem (Tokyo), 1975 May, 77(5), 1095 - 106 Conformational transitions of polypeptide chain elongation factor Tu . I . Studies with hydrophobic probes; Arai K et al.; The conformational difference between polypeptide chain elongation factor Tu (EF-Tu)-GTP and EF-Tu-GDP has been studied using hydrophobic and fluorescent probes . The interaction of EF-Tu-GDP with 1-anilino-8-naphthalenesulfonate (ANS) was measured in terms of the enhancement of the fluorescence intensity at the emission maximum of 475 nm . When EF-Tu-GDP-ANS complex was converted to EF-Tu-GTP-ANS complex by incubation with phosphoenolpyruvate and pyruvate kinase {EC 2.7.1.40}, there was a roughly 2-fold increase in fluorescence intensity and a blue shift of the emission maximum from 475 to 467 nm, indicating a conformational transition of the protein . The conformational change was found to be reversible and the spectrum promptly returned to that of EF-Tu-GDP-ANS complex upon addition of excess GDP . A similar change in the spectrum was also observed when aminoacyl-tRNA, but not deacylated tRNA, was added to EF-Tu-GDP-ANS complex . Measurement of the number of binding sites by gel filtration indicated that EF-Tu-GTP and EF-Tu-GDP bind 2.9 and 1.7 molecules of ANS, respectively . These results suggest that in EF-Tu-GTP the conformation was altered and one additional binding site for ANS was created at or near the site interacting with aminoacyl-tRNA . Another reagent, N-(1-anilinonaphthyl-4) maleimide (ANM) was covalently bound to the sulfhydryl group in EF-Tu-GDP which is essential for interaction with aminoacyl-tRNA . The binding could be determined spectrofluorometrically, since the reagent, which is nonfluorescent in aqueous solution, emitted a strong fluorescence upon binding with the sulfhydryl group, indicating a marked hydrophobicity of the local environment . Measurements of the kinetics of the binding revealed that ANM reacted rapidly with the sulfhydryl group in EF-Tu-GTP, while the reaction with that in EF-Tu-GDP proceeded more sluggishly . The difference in the reactivity of the sulfhydryl group essential for aminoacyl-tRNA binding between EF-Tu-GTP and EF-Tu-GDP probably reflects a conformational transition of the protein near the active site . These results, together with those on spin-label studies previously published (Arai, Kawakita, Kaziro, Maeda, & Onishi (1974) J . Biol . Chem . 249, 3311), demonstrate that reversible conformational transition does occur in EF-Tu on changing the ligand from GDP to GTP. Biochim Biophys Acta, 1975 May 1, 390(2), 209 - 25 Photoinduced convalent crosslinkage, in situ, of Escherichia coli 50 S ribosomal proteins to rRNA; Gorelic L; Irradiation of aqueous solutions of Escherichia coli 50 S ribosomal subunits with 253.7 nm light results in the covalent crosslinkage of the rRNA and protein components . Neither peptide bond cleavage nor protein-protein crosslinkage accompanies the crosslinkage reactionmin addition, substantial photoinduced modifications in the primary structure of the ribosomal proteins, other than crosslinkage to rRNA, are not detected . The crosslinkage of the ribosomal proteins to the rRNA proroceeds in two discrete, dose-dependent steps . The first step, requires an input of up to 3 with 10-20 Quanta of 253.7nm radiation, and results in the crosslinkage of less than half of the ribosomal proteins to the rRNA . The second step requires an input of greater than 3 with 10-20 Quanta of 253.7 nm radiation, and results in the crosslinkage of the remaining ribosomal proteins to the rRNA . The possible relationship of the nature of the corsslinkage reaction to the spatial orientations of the rRNA and protein molecules in the intact 50 S ribosomal subunits is discussed. Biochim Biophys Acta, 1975 May 1, 390(2), 141 - 54 Purification and properties of nucleic acids from an unusual cytoplasmic organelle in the flagellate protozoan Crithidia oncopelti; Spencer R et al.; A simple, rapid method for preparing bipolar bodies from sonicated (rithidia oncopelti cells, with a yield of 2-5%, is described . Apart from 2-4% contamination with unbroken cells the fraction was considered pure with respect to contamination by other nucleic acid-containing organelles, as judged by light and electron microscopy . A light satellite DNA, f bouyant density 1.695 g/ml in neutral CsCl, and derived from the bipolar body, had a Tm of 81.6 degrees C in0.15 M NaCl/0.015 M sodium citrate (pH 7.0) and a kinetic complexity of 2.7 with 109 . The bipolar body fraction also contained ribonucleoprotein particles with and s20,w of 67 S, in contrast to cytoplasmic ribosomes (87 S) . Bipolar body ribosomes contained rRNA components which migraged coincidentally with Escherichia coli rRNA (molecular weights 1.07 with 10-6 and 0.56 with 10-6) on polyacrylamide gel electrophoresis . Cytoplasmic ribosomes contained rRNAs of molecular weights 1.30 with 10-6 and 0.83 with 10-6 . Bipolar body rRNA accounted for up to 10% of the rRNA extracted from cells . The properties of these bipolar body nucleic acids provide good evidence for the bacterial nature of this subcellular component. Biochem J, 1975 May, 148(2), 349 - 52 Synthesis of alternative membrane-bound redox carriers during aerobic growth of Escherichia coli in the presence of potassium cyanide; Ashcroft JR et al.; Aerobic growth of Escherichia coli with an oxidizable substrate as carbon source in the presence of low concentrations of KCN leads to the synthesis and integration into the membrane of menaquinone and cytochromes b558, a1 and d in addition to the redox carriers normally present under aerobic growth conditions, namely ubiquinone and cytochromes b562, b556 and o . The results are discussed with reference to other phenotypic and genotypic modifications to the electron-transport chains of E . coli. Acta Pathol Microbiol Scand {A}, 1975 May, 83(3), 283 - 91 Pulmonary vascular lesions in chickens following intravenous injections of disintegrated cells of Escherichia coli; Nordstoga K et al.; Intravenous injections of disintegrated cells of Escherichia coli in chickens were almost constantly followed by extensive lesions in pulmonary arteries; the alterations consisted of mural fibrinoid necrosis, sometimes with slight intramural occurrence of mononuclear inflammatory cells and eosinophils . Massive perivascular accumulations of the same cell types were also very common findings . Affected arteries were frequently occluded by precipitates, predominantly consisting of the injected material, which were rapidly replaced by proliferating endothelial cells, resulting in obliterative lesions, where giant cells sometimes occurred . The conclusion was drawn that the arterial lesions could most adequately be categorized as hypersensitivity angiitis. Proc Natl Acad Sci U S A, 1975 May, 72(5), 1725 - 8 gene mutations.GENE MUTATIONS; Richardson JP et al.; Rho factor has been purified from a strain of E . coli containing the Su78 mutation in the suA gene and assayed in another strain with an amber mutation in the suA gene . The rho from the Su78 mutant strain is present in normal amounts but has altered termination function; it does not terminate transcription at some sites that are recognized effectively by the rho factor from the isogenic wild-type strain . Rho in cells with an amber mutation in the suA gene has been assayed by its RNA-dependent ATPase activity . Extracts of cells of this strain have only 9% as much of this rho activity as extracts of cells of the isogenic wild-type strain . These results suggest that rho is the product of the suA gene . Since mutations in the suA gene are known to decrease polar effects of mutations in other genes, it is also suggested that rho factor is at least partially responsible for polar effects. Poult Sci, 1975 May, 54(3), 674 - 81 Blood parameters of dwarf and normal pullets from growth selected lines before and after Escherichia coli challenge; Reddy PR et al.; Two experiments were conducted to study the hematological differences and the effect of challenge with Escherichia coli on the hemopoietic system among dwarfs and their normal sisters in lines selected for high and low juvenile body weight . Erythrocyte counts, packed cell volumes, and hemoglobin concentrations were significantly higher to dwarf than for normal pullets, while no such differences were noted for mean corpuscular volume, mean corpuscular hemoglobin and hemoglobin concentration . Dwarfs had a significantly lower erythrocyte sedimentation rate than normal pullets . The effect of challenge with E . coli was evident in all the groups . Body weight decreased and leucocyte counts increased significantly . Lymphopenia, accompanied by heterophilia and a consequent increase in H:L ratio was the conspicuous effect of the challenge with E . coli indicating a polymorphonuclear response . Forty-eight hours after challenge the differential response of lines and genotypes to heterophilia was uniform . The hematological data suggest that the dw gene may not contribute to resistance to bacterial diseases . Mortality and autopsy lesions data indicate that the dw gene had a deleterious effect in the low weight but not in the high weight line, suggesting that its influence on the traits measured is dependent upon the genetic background of the population. J Med Chem, 1975 May, 18(5), 528 - 30 Inhibition of phenylalanyl-tRNA synthetase by aromatic guanidines and amidines; Danenberg PV et al.; Aromatic guanidines and amidines were investigated for their ability to inhibit phenylalanyl-tRNA synthetase from E . coli B . 2-Phenylacetamidine (1), benzylguanidine (2), and N-benzylbenzamidine (3) are competive inhibitors with respect to phenylalanine, binding nearly as well as the substrate, The remainder of the inhibitors was unexpectedly found to be noncompetitive, indication the presence of a secondary binding site on the enzyme . Inhibition by these compounds appears to be specific for phenylalanyl-tRNA synthetase and requires the presence of a phenyl ring as well as the amidine or guanidine moiety. Eur J Biochem, 1975 May, 54(1), 93 - 6 No correlation between native and denatured forms of tRNA(Trp) form Escherichia coli and the resistant and sensitive molecules characterised by phosphorolysis . Two classes of conformation characterised by phosphorolysis in both native and denatured tRNA(Trp); Thang MN et al.; Some tRNA molecules in solution are sensitive to attack by polynucleotide phosphorylase while others are resistant, even with pure species of tRNA . Further analysis of this behaviour has revealed an underlying microheterogeneity in tRNA structure . In order to clarify the relation between the sensitive and resistant classes of tRNA, and the native and denatured forms with respect to amino acid acceptance, the phosphorolysis of tRNATrp from Escherichia coli has been investigated . Native tRNATrp is similar to species examined previously: resistant and sensitive classes are observed and the sensitive proportion increases with temperature . At 20 degrees C both native and denatured tRNATrp are stable under phosphorolysis conditions, and denaturated tRNATrp is found also to possess resistant and sensitive classes . About 10% of both native and denatured tRNATrp is rapidly phosphorolysed at 20 degrees C, but the rate of conversion of resistant denatured tRNATrp to the sensitive class is about twice as fact as for the native form . Thus it can be concluded that the sensitive molecules of tRNATrp attacked by polynucleotide phosphorylase are not due to denaturation. Eur J Biochem, 1975 May, 54(1), 55 - 63 Metabolism of the phosphatidylglycerol molecular species in Escherichia coli; Kito M et al.; The fractionation, turnover and biosynthesis of the phosphatidylglycerol molecular species of Escherichia coli were studied . Monoacetyldiglycerides derived from phosphatidylglycerol were separated into five subfractions; cis-vaccenyl-palmitoleyl, cis-vaccenyl-cis-vaccenyl, palmityl-palmitoleyl, palmityl-cis-vaccenyl and the disaturated molecular species on a silica gel plate impregnated with silver nitrate . Individual molecular species had different turnover rates . The palmityl-cis-vaccenyl species was metabolized faster than the others . Disaturated species were rather stable . Various phosphatidylglycerol molecular species were synthesized in the presence of sn-glycerol 3-phosphate, palmityl-CoA, palmitoleyl-CoA, cis-vaccenyl-CoA and CTP by the E . coli membrane particulate fraction . When only the proportion of palmityl-CoA among the three acyl-CoAs was increased, the molecular species containing the palmityl residue were increased . Similar results were obtained with the other acyl-CoAs . However, a temperature-sensitive incorporation of unsaturated and saturated fatty acids into phosphatidylglycerol molecular species was observed with no change in the proportions of the three acyl-CoAs, completely reflecting the in vivo unsaturated/saturated ratio. Eur J Biochem, 1975 May, 54(1), 45 - 53 Digestion with matrix-bound proteases as a possible probe for the topography of the DNA-dependent RNA polymerase from Escherichia coli; Lill HR et al.; DNA-dependent RNA polymerase lacking subunit sigma was digested with matrix-bound chymotrypsin or trypsin in the presence of 0.4 M NaCl in the monomeric form or at low ionic strength in the oligomeric form . Sigma-containing polymerase was digested in the same way . The course of proteolysis was followed by polyacrylamide gel electrophoresis after dissociation of the enzyme with detergent into subunits and the fragments produced by the hydrolysis . The following results were obtained . (a) The large subunits beta and beta' are cleaved with a much higher rate in the monomeric than in the oligomeric polymerase . (b) Both large subunits are hydrolysed with the same rate . (c) Subunit alpha is hydrolysed almost with the same rate in the monomeric and oligomeric form of polymerase . (d) The same was found for subunit sigma . (e) These effects were independent of the substrate specificity of the protease used . (f) Subunit sigma is much more susceptible to chymotrypsin than to trypsin . (g) Subunit sigma protects the large subunits beta and beta' against tryptic cleavage . These results can be explained in terms of a tentative model for the topography of the protomer-protomer interactions in RNA polymerase . According to this model subunits beta and beta' contain two sites for isologous interactions of protomers . One site can be blocked by attachment of subunit sigma . Subunits alpha and sigma do not participate directly in the association. Eur J Biochem, 1975 May, 54(1), 293 - 9 Topology of binding sites for carbamyl phosphate in aspartate transcarbamylase from Escherichia coli . The use of pyridoxal phosphate as covalent probe; Suter P et al.; Pyridoxal phosphate, a competitive inhibitor of aspartate transcarbamylase, binds to six sites in the catalytic and to twelve sites in the regulatory subunits of this hexameric protein . The properties of its association to the active sites of the enzyme are very similar to those observed with one of its substrates, carbamyl phosphate . It tightly binds to one half of the sites in the absence of succinate, an analogue of the second substrate . Since pyridoxal phosphate can be linked covalently to the protein by reduction, the distribution of the high affinity binding sites on catalytic trimers was studied after dissociation of modified holoenzyme . Electrophoresis of isolated subunits under non-denaturing conditions revealed four distinct bands, corresponding to trimers containing 0 to 3 pyridoxal phosphate derivatives . The distribution among the four species as a function of ligand concentration in the absence of succinate indicates that in the native oligomer, pyridoxal phosphate (and by extrapolation, carbamyl phosphate) binds to both catalytic trimers, rather than to three sites on a single subunit. Eur J Biochem, 1975 May, 54(1), 163 - 7 The "hidden ligand" of the galactose-binding protein; Silhavy TJ et al.; Following tryptophan fluorescence of the galactose-binding during dissociation of the ligand it has been found that glucose dissociates with a half life of less than 5 s . Similarly, fast dissociation was also observed by following release of radioactively labelled glucose from Sepharose-coupled galactose-binding protein upon dilution . Accordingly, a previous claim that the galactose-binding protein contains glucose as a non-dissociable "hidden ligand" {G . Richarme and A . Kepes (1974) Eur . J . Biochem . 45, 127-133} has to be reinterpreted Appl Microbiol, 1975 May, 29(5), 685 - 91 Effect of dichlorodifluoromethane on the appearance, viability, and integrity of Escherichia coli; Prior BA et al.; Cultures of Escherichia coli H52 were treated with liquid dichlorodifluoromethane (fluorocarbon-12 {f-12}) for 2 h at 22 C and then examined microscopically . Treated cells tended to clump, and their cytoplasms were generally less dense and less uniform in appearance than those of control cells . E . coli ML30 was exposed to f-12 at a concentration of 1.25 X saturation for times up to 1,200 min at 22 C . Cells were examined for changes in viability (plate count), permeability (as measured by exit of alpha-{14-C}methylglucoside or uptake of omicron-nitrophenyl-beta-D-galactopyranoside), release of compounds absorbing at 260 nm, and lysis (changes in absorbance at 420 nm) . Large losses of alpha-methylglucoside and of percentage of viability occurred after brief exposure to f-12 . Release of compounds absorbing at 260 nm occurred more slowly than the aforementioned events, possibly because these molecules are larger than alpha-methylglucoside . During 1,200-min exposure to f-12, the number of survivors decreased from 10-9 to 10-4 organisms/ml, the loss of compounds absorbing at 260 nm amounted to 50 percent, and 32 percent lysis occurred . Most of these changes occurred during the first 300 min of treatment . Loss of alpha-methylglucoside was almost complete after 1-min exposure to f-12 . These results suggest that death of the cell involves several stages, with a change of permeability, occurring first, followed by leakage of compounds of increasing size and, finally, lysis. Chem Biol Interact, 1975 May, 10(5), 363 - 75 Effect of 5-bromodeoxyuridine on the transcriptional properties of the genome in WI-38 human diploid fibroblasts; Hill BT et al.; Growth of WI-38 diploid fibroblasts in a medium containing 5-bromodeoxyuridine (BrdU) resulted in an increased GMP and a decreased AMP incorporation into the RNA synthesised in vitro on a chromatin template . This effect was similar to that previously reported using 3T6 mouse fibroblasts-1 . Substitution of thymidine by BrdU in DNA, also altered the characteristics of the DNA template itself, since the increased incorporation of guanine and decreased incorporation of adenine into RNA were evident also when purified, isolated DNA was used as template . The extent of replacement of AMP by GMP was proportional to the extent of replacement of thymidine by BrdU . Although there are variations in the base composition of RNA transcribed from BrdU-containing DNA templates, there are no significant difference in overall template activity or in the number of available chromatin binding sites for E . coli RNA polymerase . Confluent monolayers of BrdU-treated WI-38 fibroblasts are still able to respond with cell proliferation to a change of medium, as evidenced by an increased incorporation of (-3H)thymidine and an increase in chromatin template activity . The length of the prereplicative phase is similar in both BrdU-treated and untreated cells, although the magnitude of the increase of (-3H)thymidine incorporation is reduced by approximately 30% after BrdU treatment . The increase in chromatin template activity is associated with an increase in the number of chromatin binding sites for E . COLI RNA polymerase, suggesting that the presence of BrdU does not interfere with the availability of initiation sites or alter the actual rate of transcription. Am J Vet Res, 1975 May, 36(5), 625 - 30 In utero immunization of calves against colisepticemia; Gay CC; A total of 21 bovine fetuses was inoculated in utero with Escherichia coli antigen to determine if nonserotype-specific resistance to colisepticemia could be induced . (Seven of these fetuses were inoculated through the intact flank of the dam.) After birth, the calves were deprived of colostrum and challenge exposed to a serologically distinct E coli which killed nonvaccinated controls . Of 21 calves vaccinated as fetuses, 10 survived challenge exposure, 8 died of colisepticemia, and 3 were stillborn . Premature birth precluded an adequate period of vaccination in 6 of the calves that died of colisepticemia . A relationship was not observed between E coli serum antibody and survival after challenge exposure . The results indicate that in utero vaccination with a single serotype of E coli can result in heterogenetic protection against neonatal colisepticemia . However, the occurrence of stillbirth and premature birth in calves vaccinated in utero indicates need for furthur research before field application of this technique. Cell, 1975 May, 5(1), 69 - 74 Regulation of stable RNA synthesis and ppGpp levels in growing cells of Escherichia coli; Sokawa Y et al.; Under the balanced condition of growth of E . coli cells, no distinct difference is observed in stable RNA and protein synthesis between CP78 (rel+) and CP79 (rel minus), whereas a considerable difference is present in RNA accumulation between NF161 (rel+) and NF162 (rel minus), where NF161 smaller than NF162 . The RNA content of NF161 is lower than that of NF162 in four different cultures with different growth rates . These two sets of isogenic pairs of rel+ and rel minus strains are commonly used in the study of rel gene function; however, NF161 is a mutant in the spoT gene whose product may be responsible for the degradation of ppGpp . The basal levels of ppGpp in these four strains growing with three different growth rates were examined: NF161 (rel+ spoT minus) has a much higher content of ppGpp than do other strains . Furthermore, the contents of ppGpp tend to be lower when the above four strains are growing at a faster rate . Thus a close correlation seems to exist between the content of RNA and the basal level of ppGpp under the condition of balanced growth. Am J Clin Pathol, 1975 May, 63(5), 735 - 47 Lymphocyte surface receptors and leukemia virus-induced immunosuppression; Friedman H et al.; The number and distribution patterns of lymphocytes in the spleens and lymph nodes of Balb/c mice which express immunoglobulin surface receptors were studied in terms of the effects of a murine leukemia virus on the immune-response mechanism . Friend leukemia virus induces a prompt, marked depression of the immune response of mice to antigens such as sheep erythrocytes and E . coli LPS . A functioning T- and B-lymphocyte system is necessary for the response to the SRBC's whereas E . coli LPS, a T cell-independent antigen, stimulates B cells alone . Although the responses to both classes of antigen were markedly depressed in FLV-infected mice, the major defect appeared to be impairment of B-cell function, at least early in the course of infection . In order to examine in more detail the mechanism of interaction between FLV and lymphoid cells with Ig surface receptors, presumably B cells, immmunofluorescent analyses were performed with spleen, and lymph node cells from FLV-infected mice . Within a few days after infection there was a marked decrease in the percentage of spleen cells with Ig surface molecules, although the absolute number of these cells was either unchanged or increased due to marked splenomegaly caused by the virus . A marked decrease in the percentage of splenocytes with theta antigen, considered a marker for mature T cells, also was evident in infected mice . The number of spleen cells showing evidence of FLV infection (i.e., positive for FLV-associated antigens) increased rapidly during the first few days after infection, and within 2 to 2 1/2 weeks nearly all of the nucleated splenocytes were positive for the tumor antigen . In contrast to the results for spleen cells, there were increases rather than decreases in the percentages of Ig-positive and theta-positive cells in the lymph nodes after infection . The number of lymph-node cells that showed the presence of FLV antigen was much lower than in the spleen, and their appearance was also much slower as the leukemic process progressed . Despite these differences between spleen and lymph-node cells in terms of relative percentages of Ig- and theta-positive lymphocytes, relatively similar depressions were evident for the percentages of lymphoid cells that could redistribute their surface Ig receptors into polar caps when incubated with anti-Ig serum at 37 C . Marked impairment of the Ig-capping responses for both spleen and lymph-node cells paralleled the course of infection and development of immunosuppression . These observations indicate that murine leukemia virus infection can both alter the responsiveness of immunocompetent cells to T-dependent and independent antigens and depress the number and normal functional activity of these cells, as reflected by altered surface Ig receptors and antigens. Urology, 1975 May, 5(5), 626 - 31 Treatment of chronic prostatitis . Comparison of Minocycline and Doxycycline; Brannan W; The results of minocycline and doxycycline therapy in 41 patients with chronic prostatitis and minocycline therapy in 6 patients with acute prostatitis were evaluated . In the comparative study of chronic prostatitis, minocycline and doxycycline were given on the same dosage schedule, milligram for milligram: a loading dose of 200 mg . followed by 100 mg . twicd daily . Over-all clinical responses to therapy with either agent were generally satisfactory, and no statistically significant difference was demonstrable in this regard . In the group with chronic prostatitis treated wtih minocycline, however, all symptoms manifested before therapy had disappeared after therapy even where over-all results had been judged unsatisfactory . This was not true of the group with chronic prostatitis treated with doxycycline . Symptoms in 6 patients persisted after therapy had been terminated . Here the difference in results between the two groups was found to be statistically significant . A review of symptoms two to eight weeks after therapy revealed no significant difference between the two groups . After two years only 6 patients in the entire group with chronic prostatitis had returned with recurrent problems: 3 of these patients had been treated with minocycline and 3 had been treated with doxycycline . Results of therapy in the small series of patients with acute prostatitis treated with minocycline were generally satisfactory. J Lipid Res, 1975 May, 16(3), 244 - 6 Lyophilized 7 alpha-hydroxysteroid dehydrogenase: a stable enzyme preparation for routine bile acid analysis; Macdonald IA et al.; Preparations of 7 alpha-hydroxysteroid dehydrogenase (7 alpha-HSDH) from Escherichia coli strain 23 can be frozen and thawed without significant loss of activity . 7 alpha-HSDH may then be lyophilized into powder form, which is stable for more than 6 months (3% loss of activity) . The lyophilized 7 alpha-HSDH preparation has the additional advantage over previously described preparations of a low and stable fluorescence background when applied to the fluorometric estimation of bile acids, especially in combination with thin-layer chromatography . Analysis of duodenal aspirates from 18 normal subjects gave bile acid ratios identical with those reported earlier and obtained by using gas-liquid chromatography . A significant difference in the glycine: taurine ratio between males and females was observed. J Bacteriol, 1975 May, 122(2), 791 - 3 Location of the Escherichia coli K-12 ruv gene affecting septum formation after inhibition of deoxyribonucleic acid synthesis; Iyehara H et al.; Escherichia coli ruv gene was located at 36.1 min on the chromosome by P1 transduction experiments and the gene order his - supD - uvrC, dar4 - ruv - eda - fadD - pps was proposed . Complementation analysis by an F' factor carrying genes in the his region indicated that ultraviolet light sensitivity genes, ruv and uvrC, consist of different cistrons and wild-type alleles of these genes are dominant over the mutant alleles. J Bacteriol, 1975 May, 122(2), 749 - 63 Electron microscopic heteroduplex studies of sequence relations among plasmids of Escherichia coli: structure of F13 and related F-primes; Hu S et al.; The structure of F13, a plasmid containing lac, purE, and proC, has been determined by heteroduplex analysis . As expected for an F-prime formed by a type II excision event, it contains all the sequences of F plus a large segment of Escherichia coli chromosomal deoxyribonucleic acid . There is a sequence of F with coordinates 16.3-17.6F which has been shown in other studies to be the insertion sequence IS2 . This IS2 occurs twice on F13, once at each of the two junctions of F deoxyribonucleic acid with chromosomal deoxyribonucleic acid . The sequence alpha beta which occurs twice on F with coordinates 93.2-94.5/OF and 13.7-15.0F occurs an additional three times, twice in an inverted order relative to the alpha beta sequences of F, on the chromosomal sequences of F13 . The structures of the plasmids F13-4 and F210 have been determined . The common sequences of F13 with F152-1 (a derivative of F152, the classical F2gal) and with F13-4 and F210 have been mapped . These results partially map lac, proC, tsx, and purE on F13 . On the basis of all of these results, it is proposed that Hfr 13 (the parent of F13) was formed by recirpocal recombination between IS2 on F and an IS2 resident at a point between lac and proC on the chromosome of the F+ parent of Hfr 13 . It is proposed that this IS2 and the several alpha beta sequences on the chromosomal part of F13 are hot spots for recombination with F, i.e., for Hfr formation . The point of origin and direction of transfer of many Hfr's can be explained by this hypothesis . In particular, the sequence relations of F42-1 (Flac) and of F152-1 (F 2gal) with F13 are completely consistent with this model. J Bacteriol, 1975 May, 122(2), 686 - 90 Lipophilic chelator inhibition of electron transport in Escherichia coli; Crane RT et al.; The lipophilic chelator bathophenanthroline inhibits electron transport in membranes from Escherichia coli . The less lipophilic 1,10-phenanthroline, bathophenanthroline sulfonate, and alpha,alpha-dipyridyl have little effect . Reduced nicotinamide adenine dinucleotide oxidase is more sensitive to bathophenanthroline inhibition than lactate oxidase activity . Evidence for two sites of inhibition comes from the fact that both reduced nicotinamide adenine dinucleotide menadione reductase and duroquinol oxidase activities are inhibited . Addition of uncouplers of phosphorylation before bathophenanthroline protects against inhibition. J Bacteriol, 1975 May, 122(2), 623 - 8 Reinitiation of chromosome replication in the presence of chloramphenicol under an integratively suppressed state by R6K; Sotomura M et al.; The autonomous replication of an R plasmid, R6K (amp, str) was shown not to be affected by chloramphenicol . It provoked integrative suppression and gave rise to Hfr strains when integrated into the chromosome of a strain of Escherichia coli K-12 with a temperature-sensitive mutation in the gene, dnaA . An Hfr strain designated as Hfr(R6K) no . 1 was thus obtained and characterized . It was not completely stable as shown by a plating efficiency of 0.6 at 42 C relative to that at 30 C . The density labeling and the ultracentrifugation analysis suggested that the deoxyribonucleic acid replication in this Hfr strain did not stop immediately after completion of the round already started before temperature shift-up and the addition of chloramphenicol . These observations are discussed in relation to a possibility that the chromosome replication of this Hfr strain is under the control of the integrated plasmid at a nonpermissive temperature. J Bacteriol, 1975 May, 122(2), 592 - 8 Effect of ribonuclease on the association of deoxyribonucleic acid with the membrane in Escherichia coli; McIntosh MA et al.; The Mg-2+-Sarkosyl crystals (M band) procedure was used to study the effect of ribonuclease (RNase) A on the association of Escherichia coli deoxyribonucleic acid (DNA) with membrane . Incubation of gently prepared cell extracts with RNase results in the release of DNA from membrane . This effect appears to result from the activation, by RNase, of endonuclease I and subsequent limited activity of this deoxyribonuclease . In support of this explanation, it is demonstrated (i) that the extent of the RNase-induced loss of DNA from membrane is directly correlated with the endogenous level of endonuclease I, and (ii) that endonucleolytic activity occurs when gently lysed cell preparations are incubated in the presence of RNase. J Bacteriol, 1975 May, 122(2), 570 - 4 Mapping of sul, the suppressor of lon in Escherichia coli; Johnson BF et al.; The suppressor sul, which is allele specific for the ultraviolet sensitivity gene lon, has been mapped by conjugation and transductional crosses in Escherichia coli K-12 and B/r . Previously, sul was reported to lie in the azi region of the Escherichia coli chromosome . Evidence is presented which positions sul close to and clockwise of fabA on the Escherichia coli map . Cotransductional frequencies of 31.3% were obtained between sul and pyrD, and frequencies of 82% were obtained between sul and fabA . Also, the mucoid phenotype of K-12 lon strains grown on minimal glucose agar plates at 37 C was not significantly effected in sul derivatives . No differences between the sul of Escherichia coli B/r and that of K-12 derivatives with regard to map location or effect on mucoid production were observed. J Bacteriol, 1975 May, 122(2), 565 - 9 Rapid cessation of phospholipid synthesis in fructose-1,6-diphosphate aldolase mutants of Escherichia coli; Su CH et al.; Escherichia coli GH352, which was originally described as a temperature-sensitive strain containing a thermolabile acyl coenzyme A:monoacylglycerol 3-phosphate acyltransferase, does not now contain a thermolabile form of this enzyme . It has a defect in fructose-1,6-diphosphate aldolase and at least one additional temperature-sensitive lesion . Both strains GH352 and NP315, a temperature-sensitive aldolase mutant, show rapid cessation of 32-P1 incorporation into nucleic acids and phospholipids at 42 C . These characteristics of strain GH352 are therefore no longer attributed to thermolabile phospholipid synthesis, but can be attributed to the fructose-1,6-diphophate aldolase lesion. J Bacteriol, 1975 May, 122(2), 538 - 48 Formation of chromatographically unique species of transfer ribonucleic acid during amino acid starvation of relaxed-control Escherichia coli; Fournier MJ et al.; Examination of the transfer ribonucleic acid (tRNA) produced by starving, relaxed-control (rel minus) strains of Escherichia coli for required amino acids revealed the occurrence of a number of chromatographically unique subspecies . Leucine starvation results in the formation of new isoacceptor species of leucine-, histidine-, arginine-, valine-, and phenylalanine-specific tRNA and quantitative changes in the column profiles of serine, glycine, and isoleucine tRNA . Evidence that the unique tRNA species are synthesized de novo during amino acid starvation comes from the findings that the major unique leucine isoacceptor species is not formed in stringent control cells or in rel minus cells starved for uracil or treated with rifampin . Furthermore, heat treatment of the unique leucine tRNA does not alter its chromatographic behavior, indicating that the species is not an aggregate or nuclease-damaged form of a normal isoacceptor tRNA . The methyl acceptor activities of tRNA from leucine-starved and nonstarved rel+ or rel minus cells were found to be essentially the same . This result and the finding that the chromatographic behavior of the unique leucine-specific tRNA was not altered after treatment with tRNA methylase suggests that gross methyl deficiency is probably not the biochemical basis for the occurrence of the unique species. J Bacteriol, 1975 May, 122(2), 518 - 25 Five control systems preventing transfer of Escherichia coli K-12 sex factor F; Gasson MJ et al.; The transfer inhibition systems of 28 Fin+ plasmids have been characterized, using Flac mutants insensitive to inhibition by R100 or R62 . All F-like plasmids (except R455) and one N group plasmid determined systems analogous to that of R100; this is designated the FinOP system . None of these plasmids could supply a FinP component of the transfer inhibitor able to replace that of F itself . In addition to the FinOP and R62 transfer inhibition systems described previously, new systems were encoded by the F-like plasmid R455, the I-like plasmid JR66a, and the group X plasmid R485 . Besides inhibiting F transfer, JR66a also inhibited F pilus formation and surface exclusion, whereas R485 inhibited only pilus formation and R455 inhibited neither . All three R factors inhibited transfer of J-independent Flac elements, indicating that they act directly on one or more genes (or products) of the transfer operon, rather than directly via traJ . The tral products and transfer origin sequences of two Fin+ F-like plasmids, ColB2 and R124, appear to have similar specificities to those of F itself. J Bacteriol, 1975 May, 122(2), 492 - 501 Multiple gene loci for a single species of glycine transfer ribonucleic acid; Fleck EW et al.; The study of suppressors of tryptophan synthase A protein missense mutations in Escherichia coli has led to the establishment of two nonadjacent genetic loci (gly V and gly W) specifying identical nucleotide sequences for a single isoaccepting species of glycine transfer ribonucleic acid (tRNA GLY 3 GGU/C) . In one case, suppression of the missense mutation trpA78 was due to a mutation in a structural gene (gly W) for tRNA Gly 3 GGU/C . This mutation resulted in a base change in the anticodon and modification of an A residue adjacent to the 3' side of the anticodon, leading to the production of a tRNA Gly 3 UGU/C species . The resulting glyW51 (SU UGU/C) allele was mapped by interrupted mating and was located at approximately 37 min on the Escherichia coli genetic map . Other suppressor mutations affecting the primary sequence of tRNA Gly GGU/C and giving rise to the Ins and SU+A58 phenotypes were positioned at 86 min (glyV) . Several independently arising missense suppressor mutations resulting in the SU+A78 phenotypes were isolated and mapped at these two genetic loci (glyV and glyW) . The ratio of appearance of suppressor mutations at glyV and glyW suggests that there are three of four tRNAGly3 GGU/C structural gene copies at the glyV locus to one copy at the glyW locus . Structural genes for tRNA ly isoacceptors are now known at four distinct locations on the Escherichia coli chromosome: glyT (77 MIN), TRNA Gly 2 GGA/G; gly U (55 min), tRNAGly-1 minus; and gly V (86 MIN) AND GLYW (37 min), tRNAGly 3 GGU/C. J Bacteriol, 1975 May, 122(2), 474 - 84 Isolation and characterization of mutator strains of Escherichia coli K-12; Hoess RH et al.; A selection procedure was devised to select for mutants of Escherichia coli K-12 with enhanced rates of spontaneous frameshift mutation . Three types of mutants were isolated . Two of the mutations apparently represent alleles of previously isolated mutL13 and mutS3 . The third type of mutation, represented by two alleles, lies between lysA and thyA, and has been designated mutR . mutR increases the rate of spontaneous frameshift mutation and also the rate of base substitution mutations . The mutator phenotype is recessive . Reversion of a lac amber mutation located on an episome is increased in the presence of the mutator, indicating that mutR can act in trans . No change in sensitivity to ultraviolet irradiation or mitomycin C could be found when mutR34 was compared to the isogenic mutR+ strain . The mutator's activity was little affected by the type of medium in which the strain was grown . Deoxyribonucleoside triphosphate pools were normal in mutR34 . Intergenic recombination frequencies were the same in mutR and mutR and mutR+ strains, but a two- to threefold increase in intragenic recombination was observed in Hfr times Fminus crosses when the recipeint was mutR34 as compared with mutR+ . This increase appeared independent of the distance between the two markers within the gene in which the crossover took place. J Bacteriol, 1975 May, 122(2), 437 - 42 Events following prophage Mu induction; Razzaki T et al.; Escherichia coli strains lysogenic for a thermoinducible Mu prophage (Mu cts62) undergo rapid lysis about 50 min after heat induction . Induction of Mu cts62 apparently causes damage to the host sequences in which Mu is inserted . The normal expression of A, BU, and X genes of Mu is needed for this specific deleterious effect on the prophage-containing host sequences . Mu deoxyribonucleic acid can be shown to reintegrate extensively at different sites on the host genome during the lytic cycle after prophage induction or after infection of sensitive cells by clear-plaque mutants of Mu . We estimate that approximately 10 copies of Mu deoxyribonucleic acid are inserted per chromosome during vegetative growth . The episome rescue method for detecting vegetative Mu deoxyribonucleic acid insertion, in which an episome is transferred from the lytically infected cells to F- receipient cells, can be applied to study Mu integration without requiring the host cells to survive . It also provides an easy system to isolate Mu insertions in transmissible episomes and plasmids. J Bacteriol, 1975 May, 122(2), 352 - 8 Thermosensitive mutants of Escherichia coli K-12 altered in the catalytic Subunit and in a Regulatory factor of the glutamy-transfer ribonucleic acid synthetase; Lapointe J et al.; The glutamyl-transfer ribonucleic acid synthetase (GluRS) of a partial revertants (ts plus or minus) of the thermosensitive (ts) mutant strain JP1449 (LOcus gltx) and of a ts mutant strain EM111-ts1 with a lesion in or near the locus gltx have been studied to find the relation between these two genetic loci known to influence the GluRS activity in vitro and the presence of a catalytic subunit and of a regulatory subunit in the GluRS purified from Escherichia coli K-12 . The ts character of strain JP1449-18ts plus or minus is co-transduced with the marker dsdA at the same frequency as is the ts character of strain JP1449 . Its purified GluRS is very thermolabile and its Km for glutamate is higher than that of a wild-type GluRS . These results indicate that the locus gltX is in the structural gene for the catalytic subunit of this enzyme . The location of the mutation causing the partial ts reversion in strain JP1449-18ts plus or minus is discussed . The GluRS purified from the ts mutant strain EM111-ts1 has the same stability as the wild-type enzyme, but its Km forglutamate increases with the temperature, suggesting that the locus gltE codes for a regulatory factor, possibly for the polypeptide chain that is co-purified with the catalytic subunit. J Immunol, 1975 May, 114(5), 1523 - 31 Chemotaxis of basophils by lymphocyte-dependent and lymphocyte-independent mechanisms; Ward PA et al.; Guine pigs basophils obtained from blood or bone marrow have been studied for their chemotactic responsiveness . Chemotactic factors for basophils include a substance (lymphokine) present in culture fluids from antigen-stimulated lymphocytes, a material generated in zymosan-activated guinea pig serum, a C5 cleavage factor, and a bacterial factor . When compared with homologous neutrophils and monocytes, basophils respond most rapidly to a chemotactic stimulus . The lymphokine basophil chemotactic factor is physicochemically similar to the previously described monocyte chemotactic factor but appears to be distinct from it as well as MIF and neutrophil chemotactic factor present in the same fluids, Part of the evidence for this is the ability to detect basophil chemotactic factor in the absence of other lymphokine activities under appropriate experimental conditions . More evidence, specifically relating to the monocyte factor, is that monocytes can adsorb basophil chemotactic activity but not vice versa . This latter observation may have implications for the mechanism whereby the accumulation of basophils is controlled and limited in vivo . In addition, it was noted that specific antigen could also suppress basophil chemotaxis . Although the mechanism of this phenomenon is unclear, it could serve as a second means by which basophil accumulation may be controlled in the intact animal . Taken together, these observations provide further definition of the chemotactic behavior of basophils in general, and underscore some of the ways in which lymphocytes can influence basophils through lymphokine-dependent mechanisms. Infect Immun, 1975 May, 11(5), 1010 - 3 Significane of intravascular coagulation in canine endotoxin shock; From AH et al.; The contribution of disseminated fibrin clot formation to the pathogenesis of canine endotoxin shock was explored in control dogs and in those defibrinated with a purified fraction of Malayan pit viper venom . The hemodynamic and humoral responses after the administration of an intravenous challenge dose of Escherichia coli endotoxin were comparable as was mortality . It is concluded that, although the role of the coagulation sequence in canine endotoxin shock is unclear, it does not appear to be determinative. J Med Chem, 1975 May, 18(5), 524 - 6 Substituted 1-{(5-nitrofurfurylidene)amino}-4-imidazolin-2-ones; Snyder HR Jr et al.; A series of 1-{(5-nitrofurfurylidene)amino}-4-imidazolin-2-ones has been prepared . A new synthesis of 4-alkyl-1-{(5-nitrofurfurylidene)amino}-4-imidazolin-2-ones involving the oxidative ring closure of 5-nitro-2-furaldehyde 2-(2-hydroxyethylalkyl)semicarbazones is described . The in vitro testing of the compounds against a variety of bacteria is reported. Eur J Biochem, 1975 May, 54(1), 267 - 77 Interactions of heteroaromatic compounds with nucleic acids . 1 . The influence of heteroatoms and polarizability on the base specificity of intercalating ligands; Muller W et al.; We have examined the origins of base specificity in intercalating ligands by studying the interaction with DNA of a series of proflavine and acridine orange analogs differing in the heteroatoms present in the chromophore . Base specificity was determined by differential dialysis of the dye against DNA samples of differing G-C content . We find that G-C specificity increases as the visible absorbance band of the chromophore moves to longer wavelength, implying a relation between specificity and polarizability of the chromophore . This can be rationalized by recognizing that the G-C pair is more polar than A-T, and should therefore interact more favorably with an easily polarized ring system . We find in addition that dimethylation of the chromophore amino groups increases specificity which we discuss in terms of steric and coupled steric-electronic contributions . Our results also bear on the origin of G-C specificity in binding actinomycin to DNA . Some of the compounds studied are as G-C specific as actinomycin, yet they lack hydrogen-bonding functions as plausible determinants of specificity . This observation gives new life to the hypothesis that the specificity of actinomycin is determined primarily by preferential interaction of the chromophore with a G-C pair. J Bacteriol, 1975 May, 122(2), 425 - 32 Stability of ribosomal and transfer ribonucleic acid in Escherichia coli B/r after treatment with ethylenedinitrilotetraacetic acid and rifampicin; Yuan D et al.; A short treatment with ethylenedinitrilotetraacetic acid to permeabilize bacteria for various antibiotics or treatment with the ribonucleic acid (RNA) synthesis inhibitor rifampin causes a slow degradation of 50S and 30S ribosomal particles and of the corresponding 23S and 16S ribosomal RNA species (about 25 percent in 1 h) . The effects are additive such that the decay is about 50 percent/h if rifampin is employed after permeabilization by ethylenedinitrilotetraacetic acid . The 5S ribosomal RNA and transfer RNA are essentially stable under these conditions. Mol Biol (Mosk), 1975 May-Jun, 9(3), 459 - 66 {Phage T4 partial diploidy obtained with the method of DNA interrupted injection . I . Analysis of the genetic structure and phage progeny reproduction process}; Mekshenkov MI et al.; Phage T4 chromosome fragmentation is shown to take place when DNA injection is interrupted, a fragment length being strictly controlled by the interval from the moment of adsorbtion till the moment of an interruption . Populations of the bacteria cells infected by the phage T4 partial diploids are produced with the method of DNA interrupted injection . In the population a merodiploid involves some phage T4 amber mutant and a phage "wild" type chromosome fragment of the size controlled . To construct merodiploids the amber mutant in gene 43 and the mutant in gene 32 with the higher and the lower recombination frequency, accordingly, are used . Every merodiploid which is the heterozygote by one of these genes or which is the heterozygote by the late genes is determined to reproduce mixed phage progeny . Both the mean of the burst and the parent genotypes ratio in progeny either in the E . coli CR-63 cells or in the E . coli B depend on neither the heterozygote genetic structure nor the diploid region size . The results obtained conclude that phage genes express their function in the small fragments and the fragment recombination with the mutant partner whole chromosome follows their autonomous replication. Mol Biol (Mosk), 1975 May-Jun, 9(3), 459 - 66 {Phage T4 partial diploidy obtained with the method of DNA interrupted injection . I . Analysis of the genetic structure and phage progeny reproduction process}; Mekshenkov MI et al.; Phage T4 chromosome fragmentation is shown to take place when DNA injection is interrupted, a fragment length being strictly controlled by the interval from the moment of adsorbtion till the moment of an interruption . Populations of the bacteria cells infected by the phage T4 partial diploids are produced with the method of DNA interrupted injection . In the population a merodiploid involves some phage T4 amber mutant and a phage "wild" type chromosome fragment of the size controlled . To construct merodiploids the amber mutant in gene 43 and the mutant in gene 32 with the higher and the lower recombination frequency, accordingly, are used . Every merodiploid which is the heterozygote by one of these genes or which is the heterozygote by the late genes is determined to reproduce mixed phage progeny . Both the mean of the burst and the parent genotypes ratio in progeny either in the E . coli CR-63 cells or in the E . coli B depend on neither the heterozygote genetic structure nor the diploid region size . The results obtained conclude that phage genes express their function in the small fragments and the fragment recombination with the mutant partner whole chromosome follows their autonomous replication. Mol Biol (Mosk), 1975 May-Jun, 9(3), 426 - 34 {Possibility of internal organization of RNA and proteins in ribosomal subparticles . A structural model of Escherichia coli 30S ribosomal subparticle}; Potapov AP; The hypothetic model of reciprocal spatial arrangement of 18 from 21 proteins in the E . coli 30S ribosomal subparticle is suggested . The model is based on conception of the 16S R-A molecule macrostrand which is the right superhelix in the subparticle composition . Macrohelix's biopolarity against single-stranded sites of RNA and its small width result in that proteins binding with single-stranded RNA organized in chain, one-number sequence . The double helixes uniting the corresponding one single-stranded sites of RNA play the role of rigid transmission between them . So, in the course of subparticles reconstruction from RNA and proteins the spatially uncoupled proteins can interact without its direct contact . The model takes into consideration the vast amount of information. Biochim Biophys Acta, 1975 May 1, 390(2), 226 - 30 ATPase and GTPase activities associated with the 5-S RNA-protein complex of Escherichia coli ribosomes; Gaunt-Klopfer M et al.; Specific 5-S RNA-protein complexes were reconstituted from Escherichia coli 5-S RNA and 50-S ribosomal proteins . These complexes consist of 5-S RNA and two major proteins, namely E-L18 and E-L25 . Analysis for enzymatic activities shows that ATP and GTP are hydrolyzed and that this hydrolysis is independent of elongation factors. Biochim Biophys Acta, 1975 May 1, 390(2), 192 - 208 Affinity labeling of the ribonucleic acid component adjacent to the peptidyl recognition center of peptidyl transferase in Escherichia coli ribosomes; Yukioka M et al.; N-Iodacetylphenylalanyl-tRNA was used as an affinity label for localizing the RNA components intimately related to the peptidyl transferase activity of Escherichia coli ribosomesmthis analogue could specifically alkylate a unique nucleotide chain of 23-S RNA . The alkylation was strongly enhanced by poly(U), and was dependent on the presence of both 50- and 30-S subunits; Chloramphenicol inhibited the reaction, wheras blasticidin S stimulated it . The alkylated RNA base was found to be adenine . The nucleotide chain attacked by N-iodoacetylphenylalanyl-tRNA seemed to be localized at or near to the peptidyl recognition center of peptidyl transferase. Acta Virol, 1975 May, 19(3), 177 - 81 Excision of bromodeoxyuridine from T4-DNA by an antimutator polymerase of T4 phage; Presber W; With gene-43 (DNA polymerase)-ts-mutants of T4 phage, L98 (mutator) and CB121 (antimutator), and the T4 wild type, double labelling of DNA was carried out with (H3)-bromodeoxyuridine (BUdR) and (C14)-thymidine (TdR) . Experiments on (C14) TdR for DNA synthesis measurement in the presence of BUdR offered evidence of the ability of the CB121 mutant to excise BUdR from the DNA . This effect took place only at increased temperature . As distinct from DNA synthesis of the host, all T4 phages used preferred TdR rather than BUdR for net synthesis. Eur J Biochem, 1975 May, 54(1), 239 - 45 Studies on the de novo biosynthesis of NAD in Escherichia coli . The separation of the nadB gene product from the nadA gene product and its purification; Griffith GR et al.; Quinolinic acid (pyridine 2,3-dicarboxylic acid) which is an immediate precursor of the pyridine nucleotides, is synthesised from L-asparate and dihydroxyacetone phosphate in Escherichia coli . Extracts from certain nadB mutants complement the extracts prepared from all nadA mutants for the enzymic synthesis of quinolinate . Using the complementation assay, the quinolinate synthetase B protein has been purified more than 300-fold . The quinolinate synthetase B protein exists in all nadA and nadC mutants examined . The quinolinate synthetase A protein was present in all nadC mutants and most (but not all) nadB mutants . The facile separation of the wild-type quinolinate synthetase A and B proteins out of a nadC mutant suggests that quinolinate synthetase does not exists as a tightly bound complex . The partially puri