Nucleic Acids Res, 1978 Apr, 5(4), 1165 - 78 Reverse transcription of tRNA; Wittig B et al.; The 3' terminus of tRNA was enzymatically elongated by an oligo(A) tail . A fragment of DNA polymerase I (E . coli) was used in the presence of manganese to phase and synthesize a cleavable primer at the oligo(A)-tRNA template . When the threedimensional structure of oligo(A)-tRNA is being unfolded under conditions where the primer is still hybridized at the oligo(A) tail, the DNA polymerase I fragment transcribes oligo(A)-tRNA into DNA . Reverse transcription is slowed down and its fidelity suspended by the 1-methyladenine in oligo(A)-tRNAPhe(yeast) . The reaction is stopped by the highly modified Y-base present in this template . Approximately full length transcripts can be obtained from oligo(A)-tRNA3Gly(E.coli) . The transcription products were characterized by sequence analysis. Nucleic Acids Res, 1978 Apr, 5(4), 1403 - 11 Short RNA chains synthesized at low pH are initiated at promoter sites; Wienand U et al.; Under non optimal conditions- either with limiting substrate concentrations (1) or at low pH (2)- RNA polymerase of Escherichia coli synthesizes very short RNA chains . By sequencing one RNA species synthesized at pH 5.8 upon T7 DNA we were able to demonstrate that under these conditions transcription is initiated at a normal promoter site (here A1) but however is terminated soon afterwards at specific artificial sites not used in vivo. Nucleic Acids Res, 1978 Apr, 5(4), 1139 - 52 A new method for the purification and identification of covalently closed circular DNA molcules; Zasloff M et al.; A new technique has been developed for the rapid isolation of covalently closed circular DNA molecules . The procedure is a selective extraction based on differences in the partitioning of covalently closed circular DNA molecules and noncovalently closed species between phenol and water at acid pH and low ionic strength . Under the conditions described, linear as well as nicked circular DNA is extracted into phenol, while covalently closed circular DNA molecules remain in the water phase . The method permits the quantitative isolation of covalently closed circular DNA from either total cellular DNA or partially purified preparations, to a degree of purity comparable with buoyant density procedures. J Bacteriol, 1978 Apr, 134(1), 147 - 56 Role of Na+ and Li+ in thiomethylgalactoside transport by the melibiose transport system of Escherichia coli; Lopilato J et al.; Thiomethyl-beta-galactoside (TMG) accumulation via the melibiose transport system was studied in lactose transport-negative strains of Escherichia coli . TMG uptake by either intact cells or membrane vesicles was markedly stimulated by Na+ or Li+ between pH 5.5 and 8 . The Km for uptake of TMG was approximately 0.2 mM at an external Na+ concentration of 5 mM (pH 7) . The alpha-galactosides, melibiose, methyl-alpha-galactoside, and o-nitrophenyl-alpha-galactoside had a high affinity for this system whereas lactose, maltose and glucose had none . Evidence is presented for Li+-TMG or Na+-TMG cotransport. J Bacteriol, 1978 Apr, 134(1), 131 - 8 Assimilatory sulfate reduction in an Escherichia coli mutant lacking thioredoxin activity; Tsang ML et al.; An investigation of sulfate reduction in B tsnC*7004, a mutant of Escherichia coli lacking thioredoxin, is reported . Although thioredoxin is indispensable for the adenosine 3'-phosphate 5'-phosphosulfate (PAPS) sulfotransferase reaction under the usual conditions of assay in extracts of wild-type cells, the mutant grew as well as the wild type on sulfate, indicating that sulfate reduction is not rate limiting for growth . Another cofactor for the PAPS sulfotransferase reaction was found in extracts of the mutant that is absent from wild type cells . This cofactor was indistinguishable from thioredoxin in molecular weight but had a slightly different isoelectric point, allowing a separation of the two types of molecules by isoelectric focusing . Whereas electrons from nicotinamide adenine dinucleotide phosphate, reduced form, could be transferred via thioredoxin reductase or via glutathione and glutathione reductase to reduce thioredoxin in extracts of wild-type cells, electrons from nicotinamide adenine dinucleotide, reduced form, could only be transferred to the cofactor of the mutant via glutathione and glutathione reductase . All of the other available mutants blocked in sulfate reduction in E . coli contained normal levels of thioredoxin . The "PAPS reductase" mutant is shown to be blocked in the PAPS sulfotransferase reaction . We conclude that the cofactor found in mutant B tsnC*7004 is probably a mutated thioredoxin with an amino acid substitution that alters the isoelectric point and the reactivity with thioredoxin reductase. Appl Environ Microbiol, 1978 Apr, 35(4), 766 - 70 Physiology of L-asparaginase synthesis in recombinants of Escherichia coli A-1; Barnes WR et al.; A mating between Escherichia coli 4318 (thi leu Las- Hfr) and E . coli A-1 (Met- Las+ F-) resulted in the formation of prototrophic recombinants having L-asparaginase activities at three distinct levels . The physiology of L-asparaginase synthesis in these recombinants is decribed . One class of recombinants produced significantly more L-asparaginase than E . coli A-1 . L-Asparaginase synthesis in the recombinants was inhibited by the presence of dissolved oxygen in the medium and was transiently repressed by the presence of glucose in the same manner as that observed in the parental strains . L-Asparaginase activity was increased by the addition of oxalacetate as well as other members of the tricarboxylic acid cycle. Proc Natl Acad Sci U S A, 1978 Apr, 75(4), 1892 - 6 Functional properties of beta-galactosidase from mutant strain 13 PO of Escherichia coli; Deschavanne PJ et al.; The functional properties of CZP protein, a mutant deriving from wild-type beta-galactosidase (beta-D-galactoside galactohydrolase; EC 3.2.1.23) by a point mutation, were investigated . A large decrease of the specificity, as evaluated by the kcat/Km ratio, was observed, principally originated by a weaker binding of the substrates . The catalytic constants, whose values are strongly affected by the presence of divalent cations, were smaller or larger for mutant enzyme than for wild-type enzyme, depending upon the experimental conditions . Analysis of the kinetic pathway indicates, with some substrates, a change in the limiting step for the mutant enzyme compared to the wild type . Because the k'3 step is rate limiting for hydrolysis of p-nitrophenyl-beta-D-galactoside by the mutant enzyme in the absence of Mg2+ and its value is relatively small, it is possible to observe a burst of p-nitrophenol during hydrolysis . This provides conclusive evidence for the occurrence of a two-step mechanism, with a sequential release of the products. Surg Gynecol Obstet, 1978 Apr, 146(4), 535 - 40 The role of fibrin formation in the pathogenesis of bacteremic shock in the primate; Hammon JW Jr et al.; In this study, an attempt was made to elucidate further the role of intravascular fibrin formation in the pathogenesis of sepsis in the primate . It was found that injected live Escherichia coli caused death in primates within four to 11 hours as a result of microcirculatory failure and acidosis . Pretreatment with Arvin did not prolong the survival rate, probably because of an overloading of the reticuloendothelial system with fibrin degradation products . This study does not support an obligatory role for intravascular coagulation or fibrin formation in primate sepsis and coincides with an earlier report (6) from this laboratory on cats . Vascular damage and malfunction, secondary to mediators released by platelets, leukocytes, red cells or Hageman factor, are not ruled out. Nature, 1978 Mar 30, 272(5652), 423 - 8 A rho-dependent termination site in the gene coding for tyrosine tRNA su3 of Escherichia coli; Kupper H et al.; A set of partially overlapping DNA restriction fragments that support promoter-dependent transcription of the tRNATyr1 gene of Escherichia coli has been used to study site-specific termination in vitro . Transcription termination occurs at a specific site 224-226 nucleotides beyond the end of the structural gene and is completely dependent on rho-factor . Certain features of this site suggest differences from other termination sites previously studied . A role for specific sequence recognition is suggested. Biochim Biophys Acta, 1978 Mar 29, 518(1), 158 - 71 Purification and characterization of two tRNA-(guanine)-methyltransferases from rat liver; Glick JM et al.; tRNA(guanine-1-)-methyltransferase (EC 2.1.1.31) and tRNA(N2-guanine)-methyltransferase I (EC 2.1.1.32) were isolated from rat liver . The (guanine-1-)-methyltransferase preparation is 6800-fold purified and is free from contaminating methyltransferases or ribonuclease . The molecular weight of (guanine-1-)-methyltransferase is 83 000 . Of seven purified Escherichia coli tRNAs examined, only tRNAMetf was utilized as substrate by (guanine-1-)-methyltransferase . The methylation of tRNAMetf is maximally stimulated by 40 mM putrescine with a pH optimum of 8.0 . Using E . coli K-12 tRNA, the Km for S-adenosylmethionine is 3 micrometer and Ki for S-adenosylhomocysteine is 0.11 micrometer for (guanine-1-)-methyltransferase . (N2-Guanine-)-methyltransferase is 6200-fold purified and is also free of interfering enzymes . It has a molecular weight of 69 000 . E . coli tRNAPhe, tRNAVal and tRNAArg are substrates for this enzyme which introduces a methyl at the 2-amino group of the guanine at position 10 from the 5'-terminus of these tRNAs . The methylation of tRNAPhe is maximally stimulated by 100 micrometer spermidine with a pH optimum of 8.0 . (N2-Guanine-)-methyltransferase has a Km for S-adenosylmethionine of 2 micrometer and a Ki for S-adenosylhomocysteine of 23 micrometer with E . coli K-12 tRNA as methyl acceptor. Biochim Biophys Acta, 1978 Mar 29, 518(1), 150 - 7 Two-component ribonucleotidyl transferase from Escherichia coli . III . Effect of nucleoside diphosphates on synthesis and pyrophosphorolysis of polyribonucleotides by the enzyme; Prangishvili DA et al.; 1 . The capacity of two-component ribonucleotidyl transferase to catalyze pyrophosphorolysis of polyribonucleotides is studied . 2 . It is shown that nucleoside diphosphates (NDP), not being substrates for the enzyme, activate both the synthesis and pyrophosphorolysis of polynucleotides by the enzyme . The concentration of NDP is important for this effect: with an increase of NDP concentration the rate of synthesis increases and reaches a plateau at 10(-5) M NDP, while the rate of pyrophosphorolysis, attaining maximal values at 10(-5)--10(-3) M NDP, decreases with a further increase of NDP concentration . 3 . The possible biological role of two-component ribonucleotidyl transferase is discussed. J Biol Chem, 1978 Mar 25, 253(6), 1910 - 20 Isolation and characterization of phosphothioredoxin from Excherichia coli; Pigiet V et al.; Thioredoxin was isolated as a phosphoprotein from actively growing cultures of Escherichia coli . Labeling was performed in vivo by growing cells in the presence of 32P-labeled inorganic phosphate, and phosphothioredoxin was purified in one step by immunoabsorption to a thioredoxin antibody column . The stoichiometry of phosphate bound was 0.7 to 0.8 mol of phosphate/mol of thioredoxin . The phospho-amino acid linkage was identified as a thiol phosphate by several criteria: (a) the maximum lability of the phosphate bond was between pH 2.5 and 3.5 (t1/2 (37 degrees) = 200 h (pH 7 to 8); 0.4 h (pH 3.0); 200 h (pH 1.0)); (b) the phosphate linkage was very labile in the presence of iodine at neutral pH (t1/2 less than 1 min); and the phosphopeptide was identified as Cys32-Gly-Pro-Cys35-Lys, the same sequence previously implicated as the active site for disulfide-linked oxidation-reduction reactions . Phosphate was distributed on either cysteine, with 60% of the phosphate bound to cysteine32 . Results are discussed in terms of the possible role of phosphothioredoxin as an intermediate in phosphotransferase reactions. J Biol Chem, 1978 Mar 25, 253(6), 1827 - 31 Purification and properties of a pig heart thiolase with broad chain length specificity and comparison of thiolases from pig heart and Escherichia coli; Staack H et al.; A thiolase (acetyl CoA acyltransferase, EC 2.3-1.16) which acts on substrates of various chain lengths (thiolase I) has been purified from pig heart muscle 366-fold to near homogeneity as judged by gel electrophoresis . Its molecular weight was estimated to be 200,000 in the absence and 46,000 in the presence of sodium dodecyl sulfate . Kinetic measurements with acetoacetyl coenzyme A, 3-ketohexanoyl-CoA, 3-ketooctanoyl-CoA, and 3-ketodecanoyl-CoA yielded apparent Km values of 16, 8.3, 2.4, and 1.8 micron, respectively, whereas apparent Vmax values of 65 to 69 mumol/min/mg were obtained with all substrates except for acetoacetyl-CoA, with which a value of 26.5 mumol/min/mg was observed . Antibodies prepared against this thiolase were used to demonstrate that thiolase I and acetoacetyl-CoA thilase (thiolase II) from pig heart mitochondria are immunologically unrelated . The antibodies cross-reacted, however, with thiolase I from beef heart . Kinetic constants (Km, Vmax) were also determined for thiolases I and II from Escherichia coli, as were the native and subunit molecular weights of E . coli thiolase II . Although the E . coli thiolases were found to be immunologically distinct from the pig heart enzymes, their physical and kinetic properties are strikingly similar to those of the heart thiolases . In view of this finding and in view of the known physiological functions of the E . coli thiolases, it is proposed that thiolase I from pig heart is only involved in fatty acid metabolism, whereas thiolase II functions solely in ketone body degradation. N Z Med J, 1978 Mar 22, 87(608), 201 - 3 Escherichia coli meningitis in the newborn: follow-up study; Farmer K et al.; Followup study of 22 cases of meningitis due to Escherichia coli (E . coli) in the newborn period showed a mortality rate of 7 out of 22 (31.88%), severe physical and mental sequelae occurred in one case and mild to moderate sequelae in two others . Most psychometric tests were within normal range in the survivors examined . There was a correlation between low birth weight and a high CSF protein with adverse prognosis. Biochemistry, 1978 Mar 21, 17(6), 1068 - 72 Kinetic studies of Escherichia coli transfer RNA (uracil-5-)-methyltransferase; Shugart L; The kinetic mechanism of a semipurified tRNA (uracil-5-)-methyltransferase (EC 2.1.1.35) preparation obtained from Escherichia coli has been studied at pH 9.0 in the presence and absence of products . The initial velocity and product inhibition patterns are consistent with a random order of addition of adenosylmethionine and transfer RNA to separate and independent binding sites on the enzyme . Values have been determined for the Michaelis and product inhibitor constants. Biochemistry, 1978 Mar 21, 17(6), 1054 - 9 Photobinding of 8-methoxypsoralen to transfer RNA and 5-fluorouracil-enriched transfer RNA; Ou CN et al.; The photobinding of {3H}8MOP to tRNA upon irradiation at 365 nm in the absence of O2 was determined by gel filtration . The maximum photobinding was found to be ca . 4 mol of 8MOP er mol of tRNA and 5FU-tRNA, with an overall quantum yield of 2.3 X 10(-3) . The photobinding kinetics for 8MOP-tRNA showed an apparent induction period or sigmoidal kinetic curve, indicating a specific initial photobinding site on tRNA which was identified as 4-thiouridine at position 8 from the 5'-end of Escherichia coli tRNA . Photobinding of 8MOP to 5FU-tRNA proceeded without an apparent induction period . 8MOP-tRNA and 8MOP-5FU-tRNA adducts were characterized by absorption, fluorescence, and CD spectroscopy . A modified procedure was also developed to analyze the nucleoside composition in modified 8MOP-tRNA and 8MOP-5FU-tRNA . The results showed that 8MOP photochemically added mainly to pyrimidine bases . The photobinding of 8MOP changed the conformation (secondary in particular) of tRNA and inhibited aminoacyl-tRNA synthetase activity. Mol Gen Genet, 1978 Mar 20, 160(1), 81 - 7 UV-inducible repair: influence on survival, dimer excision, DNA replication and breakdown in Escherichia coli B/r Her+ cells; Sedliakova M et al.; Using a model of double-UV-irradiation with inducing1 (non-lethal) and lethal fluences2 we have studied involvement of UV-inducible functions in post-UV-irradiation restoration processes and survival of Escherichia coli B/r thy-trp-Hcr+ . Cells irratiated with both inducing and lethal fluences differed from cells irradiated with lethal fluence in the following respects: They were more UV resistant; they did not die during postincubation with chloramphenicol3; they exhibited a significant reduction in dimer excision; they were able to resume DNA replication and produce normal-sized DNA molecules in the presence of chloramphenicol . Since induction was provoked in cell prestarved for amino acids it was not associated with damage to points active in replication . However, the inducible product was more important for repair of replicating than non-replicating cells . The data indicate that protein necessary for resumption of DNA synthesis after UV is not constitutive but inducible. Mol Gen Genet, 1978 Mar 20, 160(1), 77 - 80 Non-coordinate expression of the neighbouring genes rplL and rpoB,C of Escherichia coli; Hayward RS et al.; The operon rpoB,C of Escherichia coli codes for the RNA polymerase subunits beta and beta' . rpoB procedes rpoC in the direction of transcription . The nearest characterised gene to rpoB on the chromosome is rplL, which codes for the ribosomal proteins L7/12 . rplL appears to be transcribed in the same direction as rpoB,C, and it has been suggested that all three genes may lie in a single operon . The drug rifampicin induces increased production of beta and beta' in suitable strains of E . coli . We show here that alpha and sigma are also induced, whereas synthesis of L7/12 is not detectably affected. Mol Gen Genet, 1978 Mar 20, 160(1), 115 - 8 Cloning of a restriction fragment of phage mu DNA coding for early functions; Schumann W et al.; The DNA of an E . coli K12 strain harboring ten wildtype Mu prophages was restricted with endonuclease EcoRI, and the fragments ligated into the plasmid vector pMB9 . Upon transformation of a strain carrying a heat inducible (Mu cts62) prophage, one temperature-resistant transformant was isolated . This transformant strain harbors the hybrid plasmid pKN001, containing the EcoRI.C fragment of Mu DNA as shown by restriction and heteroduplex analysis . Stable transformants of pKN001 are immune to superinfection with phage Mu . Transformation of Mu sensitive bacteria with pKN001 results in killing of the recipients (10(-4) surviving bacteria) . The killing function is not expressed upon transformation of Mu-immune (lysogenic) bacteria. Eur J Biochem, 1978 Mar 15, 84(2), 493 - 8 Isolation and properties of two protein kinases from yeast which phosphorylate casein and some ribosomal proteins; Kudlicki W et al.; Three fractions of protein kinase from postribosomal supernatant of Saccharomyces cerevisiae, active in phosphorylation of casein, were resolved on DEAE-cellulose . Two of these fractions: protein kinase 1 and protein kinase 3, were further purified about 1000 and 1800-fold respectively . The kinase 1 appeared to exist as a monomer with a molecular weight of 50 000 and utilized only ATP as phosphoryl donor . The protein kinase 3 was an aggregated form of enzyme with a molecular weight of above half a million and used both ATP and GTP for protein phosphorylation . Both isolated enzymes showed variations in respect to Michaelis constants, and inhibitory effects exerted by monovalent cations and nucleotide phosphates . The activity of the kinases was not affected by the presence of cAMP (adenosine 3':5'-monophosphate) or cGMP, however, only protein kinase 1 appeared to be a cAMP nucleotide-independent enzyme . Despite these differences both enzymes equally phosphorylated two strongly acidic proteins of the 60-S ribosome subunit, possibly related to L7, L12 of Escherichia coli. Biochem J, 1978 Mar 15, 170(3), 593 - 8 Genetic complementation between two mutant unc alleles (unc A401 and unc D409) affecting the Fl portion of the magnesium ion-stimulated adenosine triphosphatase of Escherichia coli K12; Cox GB et al.; A new mutant strain of Escherichia coli in which phosphorylation is uncoupled from electron transport was isolated . A genetic-complementation analysis, using partial diploid strains, showed that the new mutant allele, uncD409, is in a gene distinct from the other previously identified genes uncA, uncB and uncC . A strain carrying the uncd409 allele has no Mg2+ ion-stimulated adenosine triphosphatase activity and is therefore phenotypically similar to strains carrying the uncA401 mutant allele . Complementation between the uncA401 and the uncD409 alleles occurred, as indicated by growth of partial diploid strains on succinate and their growth yields on limiting concentrations of glucose . Complementation was confirmed by using membranes prepared from the above partial diploids . Such membranes were found to have Mg2+-stimulated adenosine triphosphatase activity, ATP-dependent transhydrogenase activity ADP-induced atebrin-fluorescence quenching and low but significant amounts of oxidative phosphorylation. J Biol Chem, 1978 Mar 10, 253(5), 1738 - 42 A conditional lethal mutant of Escherichia coli which affects the processing of ribosomal RNA; Apirion D et al.; A temperature-sensitive mutant strain was isolated from an RNase III-(rnc) strain of Escherichia coli . At the permissive temperature it behaves like the parental strain, but at the nonpermissive temperature it fails to produce normal levels of 23 S and 5 S rRNA, while instead the 25 S rRNA species becomes very prominent . (The 25 S molecule appears in rnc cells and contains 23 S rRNA sequences) . When an rnc+ mutation was introduced to such a strain, or when the rnc mutation was replaced by an rnc+ allele, the strain remained temperature-sensitive . At the permissive temperature such strains synthesized rRNA like any other E . coli strain, but at the nonpermissive temperature they remained unable to synthesize normal levels of 5 S rRNA, and instead a larger molecule was accumulated . The simplest interpretation of theses findings is that the mutant strain contains a temperature-sensitive processing endoribonuclease, RNase E, which normally introduces a cut in the growing rRNA chain somewhere between the 23 S and the 5 S rRNA cistrons . These findings help also to explain the nature and origin of the various rRNA species observed in RNase III- cells and add to our understanding of processing of ribosomal RNA in normal cells of Escherichia coli. J Biol Chem, 1978 Mar 10, 253(5), 1323 - 4 Differential effect of hydroxyurea on a ribonucleotide reductase system; Yeh YC et al.; Infection of Escherichia coli with phage T4 induces a large increase in ribonucleotide reductase activity . We show that hydroxyurea inhibits T4-induced CDP, ADP, UDP, and GDP reductase activities in vitro . Moreover, there are significant differences in the degree of inhibition of each ribonucleotide reductase activity . The reductase activities for CDP and ADP are more sensitive to hydroxyurea than those for UDP and GDP, particularly at high hydroxyurea molarities . As little as 5 x 10(-4)M hydroxyurea lowers CDP and ADP reductase activities to 25 to 30% whereas as much as 0.5 M hydroxyurea is needed to lower UDP and GDP reductase activities to 50%. J Biol Chem, 1978 Mar 10, 253(5), 1613 - 8 Nucleotide sequence of DNA template for the 3' ends of SV40 mRNA . II . The sequence of the DNA fragment EcorII-F and a part of EcorII-H; Thimmappaya B et al.; The nucleotide sequence for two-thirds of restriction endonuclease fragment EcoRII-F and part of RII-H of SV40 DNA is presented . This segment of SV40 DNA is complementary to the sequence near the 3' end of early mRNA . This sequence could be translated in one reading frame to form a large protein . However, in a second translational frame there are four AUG codons followed by 91 sense triplets, followed by a termination codon . These results provide the sequence for the entire 3' untranslated ends of SV40 early and late mRNAs and for the DNA beyond the 3' ends of the mRNAs . The ends of early and late mRNA are transcribed from the opposite strands of the same segment of DNA . At or beyond the 3' ends of both early and late mRNA are sequences whose transcripts would include uridylic acid-rich products. Biochemistry, 1978 Mar 7, 17(5), 850 - 7 Multiple thymine dimer excising nuclease activities in extracts of human KB cells; Cook KH et al.; Crude extracts of human KB cells grown in suspension culture contain enzyme activity that catalyzes the preferential excision of thymine-containing pyrimidine dimers from UV-irradiated E . coli DNA specifically incised adjacent to dimer sites . Fractionation of KB cell crude extracts reveals the presence of three such activities with distinct affinities for both DEAE-cellulose and phosphocellulose . One of the activities (activity B) is distinguished by its s 20,w (2.6) and isoelectric point (9.0) from the other two (activities A and C) which have similar s 20,w's (3.0-3.2) and isoelectric points (6.0) . All three differ in their extent of stimulation by divalent cation and inhibition by NaCl or a sulfhydryl group inhibitor . These results indicate that multiple 5' leads to 3' dimer excision nuclease activities exist in human cells; however, there is as yet no direct evidence that these enzymes are functional in nucleotide excision repair in vivo. Hoppe Seylers Z Physiol Chem, 1978 Mar, 359(3), 407 - 11 Synthesis and application of a new bifunctional amidination reagent; Muller J et al.; Methyl 4-hydroxy-3-nitrobenzimidate hydrochloride (I) is presented as a newly developed amidination reagent . It is synthesized in two steps from commercially available 4-hydroxybenzonitrile . Its incorporation into proteins can be easily determined spectroscopically . The activities of the three enzymes lactate dehydrogenase (pig heart), alkaline phosphatase (calf intestine) and tryptophan synthase (E . coli) were not greatly reduced after modification with the reagent . The nitro groups can be reduced by mild treatment with Na2S2O4 without alteration of the enzymatic activity . The newly formed aromatic amino groups can further be made to react at lower pH than the native amino groups. J Biochem (Tokyo), 1978 Mar, 83(3), 693 - 8 Galactose metabolism in Dictyostelium discoideum . Regulation of galactose-1-phosphate-uridyl transferase during growth and development; DeMeglio DC et al.; Dictyostelium discoideum is able to metabolize {1-14C}galactose to 14CO2 despite the observation that galactose is inhibitory with respect to growth . Galactose-1-phosphate uridyl transferase activity is present throughout growth and development and varies in activity only slightly during the entire life cycle of D . discoideum, in contrast to the rapid increase in UDP-glucose 4-epimerase activity during development . Therefore, in D . discoideum, these two enzymes of the Leloir pathway are independently regulated, unlike E . coli where these enzymes are coordinately controlled. J Trauma, 1978 Mar, 18(3), 166 - 72 Ionized calcium and magnesium: the effect of septic shock in the baboon; Trunkey D et al.; Ionized calcium (Ca2+) and ionized magnesium (Mg2+) are important intracellular "second messengers" and control exictation-contraction coupling, excitation-secretion, oxidative phosphorylation, and mitochondrial acid-base balance . The present study examines the effect of septic shock on serum (Ca2+) and (Mg2+) . Five adult female baboons were subjected to live E . coli septic shock and then resuscitated . Three baboons served as controls . Ca2+ was measured by the Orion SS-20 flow-through calcium electrode and Mg2+ calculated by the method of Killen . Other measurements included: total calcium, bound calcium, total magnesium, bound magnesium, phosphate, albumin, globulin, hemotocrit, and total protein . This study shows that there are significant disturbances of Ca2+ and Mg2+ during septic shock in the baboon . These disturbances may in part explain cellular dysfunction during shock including: decreased myocardial contractility, inappropriate secretion of endocrine cells, decrease in oxidative phosphorylation, and mitochondrial acidosis. J Bacteriol, 1978 Mar, 133(3), 1419 - 26 Physiological characterization of an Escherichia coli mutant altered in the structure of murein lipoprotein; Yem DW et al.; Studies using isogenic transductant strains mlpA+ and mlpA as well as reversion analysis suggested that the physiological consequences of a structural gene mutation in murein lipoprotein include (i) increased sensitivity toward chelating agents ethylenediaminetetraacetic acid and ethyleneglycol-bis (beta-aminoethyl ether)-N,N-tetraacetic acid, (ii) leakage of periplasmic enzyme ribonuclease, (iii) weakened association between the outer membrane and the rigid layer accentuated by Mg2+ starvation, resulting in the formation of outer membrane blebs, and (iv) decreased growth rate in media of low ionic strength or low osmolarity . It is suggested that the bound form of lipoprotein plays an important role in the maintenance of the structural integrity of the outer membrane of the Escherichia coli cell envelope . Other outer membrane components may also contribute to the anchorage of outer membrane to the rigid layer, probably through ionic interactions with divalent cations . Using the phenotype of ribonuclease leakage as an unselected marker in a three-factor cross with P1 transduction, we were able to establish the gene order of man mlpA aroD pps on the E . coli chromosome. J Gen Microbiol, 1978 Mar, 105(1), 51 - 62 Electron microscopy and computerized evaluation of some partially denatured group P resistance plasmids; Burkardt HJ et al.; DNA of the R plasmids RP1, RP4 and RP8 was isolated from various hosts . The lengths of these plasmid molecules were determined by electron microscopy: RP1 and RP4 were about 19 micron long, RP8 measured 31 micron . An RP4 plasmid mutant, designated RP4a, was isolated from Escherichai coli; it was about 1 micron shorter than normal RP4 DNA . To investigate the molecular relationship between RP4, RP4a and RP8 DNAs of these plasmids were partially denatured and examined in the electron microscope . Measurements of the length and denaturation pattern of the DNA molecules were used to construct physical maps . A new computer program was devised for the alignment of the circular molecules, and the effect of variations of different parameters on the reliability of the program was tested . A comparison of the denaturation pattern of RP4 and RP8 indicated that RP8 was composed of total RP4 plus an additional DNA fragment . The RP4a mutant plasmid could be defined as a deletion mutant with loss of 1 micron DNA. Antimicrob Agents Chemother, 1978 Mar, 13(3), 427 - 9 Central nervous system chloramphenicol concentration in premature infants; Dunkle LM; Four premature infants under 1,500 g were treated with parenteral chloramphenicol for central nervous system infections due to organisms resistant to the penicillins . Serum, cerebrospinal fluid (CSF), and ventricular fluid concentrations of chloramphenicol were measured frequently during therapy and were used to maintain drug dosages in the safe and therapeutic range . Concentrations of chloramphenicol in the lumbar CSF and ventricular fluid had a mean of 23.3 +/- 7.7 micrograms/ml, consistently greater than 45% of peak serum levels . These data show that chloramphenicol enters the CSF in both ventricular and lumbar regions in therapeutic concentrations when administered intravenously . The clinical usefulness of this drug remains to be investigated . The importance of monitoring serum drug levels during therapy is emphasized. J Environ Pathol Toxicol, 1978 Mar-Apr, 1(4), 397 - 402 Depression of humoral immunity in rats following chronic developmental lead exposure; Luster MI et al.; Chronic pre- and postnatal exposure of CD rats to low levels of lead resulted in a marked depression in the antibody response to SRBC as well as decreased serum IgG levels . Serum IgM and IgA levels were normal . The fact that the antibody response to LPS, a thymus independent antigen, was not altered, suggested that the T-lymphocyte rather than the B-lymphocyte is affected by lead exposure . Additional significance is lent to these results when blood lead levels in treated rats were found to be similar to levels found in many children in urban areas. Zh Mikrobiol Epidemiol Immunobiol, 1978 Mar, (3), 45 - 50 {Effect of exogenous interferon on the transplantation reactions of mice}; Ogurtsov RP et al.; The authors studied the influence of the serum obtained at various periods after the administration of interferon inductors (New castle disease virus, amino ethylisothiouronium, E . coli endotoxin) on the rate of rejection of the skin or cell transplant of mice C3H and CBA, and also CC57Br . The allogenous skin transplant perished more rapidly; there was also an acceleration of elimination of allogenous lymphoid cells, suppression of colony formation by the cells of allogenous bone marrow in the spleen of the irradiated recipient in administration of the serum obtained at the period of maximal content of interferon induced by the Newcastle disease virus and by amino ethylisothiouronium . The cytotoxic activity of lymphocytes of mice CC57Br against the allogenous target cells rose in the presence of these sera . The serum containing interferon induced with E . coli endotoxin failed to influence the rate of the allotransplant rejection and did not increase the cytotoxic activity of lymphocytes. Vopr Med Khim, 1978 Mar-Apr, 24(2), 252 - 5 {Effect of S-nucleosyl-L-homocysteines on the activity of DNA methylases}; Nikol'skaia II et al.; It was studied effect of S-adenosyl, -uridyl, -citidyl and -inosyl homocysteines on activity of bacterial adenine and cytosine methylases from E . coli CK as well as on guanine methylase specific for DDVI phage . S-adenosyl homocysteine was shown to be the strong inhibitor of methylation; 10 micrometer of the substance inhibited all the enzymes studied by 98--99% . Use of total enzymatic preparations did not enable to find a difference in affinity of S-uridyl, -citidyl, and -inosyl homocysteines to various DNA methylases studied . All these preparations inhibited DNA methylases by 55--65% . Increase in concentration of inhibitor up to 20 micrometer did not elevate the inhibitory effect . Action of S-nucleosyl homocysteines did not depend on the type of acceptory DNA. Cell, 1978 Mar, 13(3), 419 - 26 IS1 insertion generates duplication of a nine base pair sequence at its target site; Grindley ND; Three independent integrations of the E . coli insertion sequence, IS1, into the gal operon have been analyzed . DNA sequences of portions of the wild-type galT gene which act as the target sites for these insertions, as well as the corresponding gal/IS1 junctions, are reported . Two features are particularly noteworthy . First, similar sequences appearing in inverted orientation consitute the ends of IS1: 18 of the terminal 23 base pairs at each end are identical . Second, in all three insertions, a 9 base pair segment found once in the wild-type sequence at the site of insertion is duplicated and appears in the same orientation at each end of the inserted element . The sequence of this 9 base pair repeat is different for each insertion analyzed . No homology between the inverted repeat sequences at the ends of IS1 and the sequences of the target sites is observed . Models for the mechanism of IS1 insertion are proposed. Cell, 1978 Mar, 13(3), 411 - 8 DNA sequence at the integration sites of the insertion element IS1; Calos MP et al.; We have detected two independent occurrences of insertion mutations in the lacl gene of E . Coli, and have used small plasmids carrying the l gene to purify large amounts of DNA containing these insertions . Analyses with restriction endonucleases and DNA sequencing techniques establish that both insertions involve the previously characterized element IS1 . In each case, the integration of IS1 into the l gene DNA is associated with a directly repeated sequence of 9 nucleotides appearing at each end of the insertion element . Since one of these sequences was present in the wild-type gene, the second sequence either preexisted in the IS1 before integration, or else was generated by the process of insertion itself . The 9 base repeat is different in both cases . We discuss the relevance of these findings to the mechanism of integration of transposable elements. Res Vet Sci, 1978 Mar, 24(2), 254 - 7 The role of oral immunisation in stimulating Escherichia coli antibody of the IgM class in porcine colostrum; Chidlow JW et al.; Oral immunisation with Escherichia coli polysaccharide antigens provided a primary antigenic stimulus which facilitated the production of humoral IgM antibody following a single parenteral antigen dose . The peak antibody response of preparturient sows was manipulated to coincide with the period of colostrum formation so that high levels of IgM antibody were made available for neonatal defence . The characteristics of the immune response remained unchanged on reintroduction of the immunisation schedule for a second gestation period. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1265 - 9 Phenotypically cryptic EcoRI endonuclease activity specified by the ColE1 plasmid; Miller CA et al.; An endonuclease having EcoRI specificity is produced by bacteria containing the ColE1 plasmid . Such bacterial cells fail to express restriction or modification functions in vivo, and phage or plasmid DNA obtained from ColE1-containing cells has unmodified EcoRI sites that are cleaved in vitro by purified EcoRI endonuclease or by enzyme extracted from bacteria that carry ColE1 . No EcoRI DNA methylase activity associated with ColE1 has been detected . The finding of phenotypically cryptic ColE1-dependent EcoRI endonuclease activity and the absence of any detectable EcoRI modification system in ColE1-containing cells suggest a control mechanism that appears to prevent functional expression of the ColE1-determined enzyme in vivo. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1209 - 12 Precursors of three exported proteins in Escherichia coli; Randall LL et al.; Arabinose-binding protein, maltose-binding protein, and lambda receptor are synthesized in vitro on membrane-bound polysomes from Escherichia coli . All three proteins are exported from the cytoplasm of E . coli and all three are made in vitro in a form a few thousand daltons larger than the authentic protein . The larger form of arabinose-binding protein is also detected in vivo by pulse labeling . It is concluded that the larger forms of the exported proteins are precursors containing an extra sequence . In contrast to the above, when the intracellular protein elongation factor Tu is synthesized in vitro on free polysomes, it is not detectably larger than the authentic form. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1181 - 4 Tetrakis(acetoxymercuri)methane: a polymetallic reagent for labeling sulfur in nucleic acids; Strothkamp KG et al.; Tetrakis(acetoxymercuri)methane binds to the sulfur atom of 6-thioguanosine and also to the 4-thiouridine residue of Escherichia coli tRNAVal . A 4:1 complex is formed between 6-thioguanosine and tetrakis(acetyoxymercuri)methane . Addition of 3 equivalents of N,N-dimethyl-2-amino-ethanethiol hydrochloride to tetrakis(acetoxymercuri)methane effectively blocks three of the four mercury atoms, rendering the compound monofunctional toward 6-thioguanosine . Under appropriate conditions, tetrakis(acetyoxymercuri)methane, in the presence or absence of N,N-dimethyl-2-amino-ethanethiol hydrochloride, binds to the 4-thiouridine residue in E . coli tRNAVal without forming intermolecular crosslinks . These results suggest that tetrakis(acetoxymercuri)methane will be a useful polymetallic reagent for labeling sulfur sites in polynucleotides . It may also prove to be a valuable reagent for preparing heavy metal derivatives of proteins for x-ray crystallographic study. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1140 - 4 Two chromatographically separable forms of Escherichia coli elongation factor Tu; Geiser M et al.; Two forms of the elongation factor Tu from Escherichia coli have been separated by chromatography on DEAE-Sephadex A50 . Obvious chromatographic artifacts have been ruled out by investigation of the elution profile of GDP (a component of the column buffer as well as a ligand of Tu) and by rechromatography of the two components, either separately to give the component peaks or together to give a double peak . The two components have been confirmed as Tu by the poly(uridylic)-dependent polyphenylalanine synthesis and by the distribution of the Tu protein as quantitated from sodium dodecyl sulfate/polyacrylamide gel electrophoresis . Complexes with the elongation factors Ts and G have also been ruled out by activity profiles and by quantitation of the protein distribution, again on gels . The distribution of the two forms between ribosomal and supernatant fractions has been examined: one is bound preferentially to the ribosomal fraction and the other is found in the supernatant fraction . The possible significance of this is discussed. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1071 - 5 Specific binding of tRNAMet to 23S rRNA of Escherichia coli; Dahlberg JE et al.; tRNAMetf binds to 23S rRNA of Escherichia coli, forming a complex with a melting temperature of 75 degrees (in 0.6 M NaCl) . The regions within the RNAs that bind to each other have been isolated and their nucleotide sequences have been determined . The interacting region in tRNAMetf is 17 nucleotides long, extending from G5 in the acceptor stem to D21 (D = 5.6-dihydrouridine) in the D loop . The sequence in 23S rRNA is complementary to that sequence except for an extra Up in the middle and allowing a Gp.D base pair . We propose that association of these two sequences may play a role in initiation of protein synthesis by tRNAMetf . In addition, part of this sequence in 23S rRNA may also stabilize tRNA binding to the ribosome during elongation of nascent polypeptides. Mol Biol (Mosk), 1978 Mar-Apr, 12(2), 413 - 20 {Formation of the compact form of DNA in solution after reaction with spermidine}; Skuridin SG et al.; The formation of compact particles from double-stranded DNA molecules in water-salt solutions containing spermidine was studied . It has been shown that in solutions of low ionic strength (0.01 M NaCl) DNA-spermidine complexes have the form of large particles which scatter UV-light . Electron micrographs show that such complexes formed at certain molar ratios spermidine/DNA may exist both as intermolecular aggregates and as toroidal particles 1500 A in diameter . The CD spectra of solutions containing DNA-spermidine complexes are characterized by the positive band (delta epsilon max = 10) at 265--270 nm . The appearance of the positive CD band may be caused by two factors: interaction between DNA and spermidine may lead to the alteration of the DNA secondary structure "in direction to A-form" or intermolecular aggregation, which may change the initial shape of the CD spectrum . The exclusion of spermidine molecules from DNA-spermidine complexes by Na+ ions in presence of poly(ethylene glycol) which occurs as the ionic strength increases from 0.01 to 0.3 does not lead to decompactization of DNA molecules but is accompained by the appearance of the intense negative CD band at 270 nm. Mol Biol (Mosk), 1978 Mar-Apr, 12(2), 397 - 403 {Peptidyl transferase center of ribosomes . I . Difference in the substrate specificity of the acceptor and donor portions}; Popovkina SV et al.; Some model substrates of the peptidyl transferase centre of E . coli MRE-600 ribosomes were synthesised and tested in a cell-free system without a template . In these substances the nucleic bases were linked covalently with the ribose residue or had a limited rotation about the glycosidic bond . 3'(2')-O-(N-formylmethionyl)-8-bromoadenosine 5'-phosphate and 3'(2')-O-phenylalanyl-8,5'-anhydro-8-mercaptoadenosine were shown to possess a high peptide donor and acceptor activity correspondingly . Contrary to that 3'(2')-O-phenylalanyl-8-bromoadenosine was practically inactive as a peptide acceptor and 3'(2')-O-(N-formylmethionyl)-8,5'-anhydro-8-mercaptoadenosine had no peptide donor activity at all . PMR and CD spectra of the compounds synthesised were investigated . The significance of conformation of the model substrates on their activity is discussed. Mol Biol (Mosk), 1978 Mar-Apr, 12(2), 385 - 96 {Study of the structure of tRNA by the energy migration method using fluorescent labels covalently bound to specific tRNA loci}; Strel'tsov SA et al.; Optical and fluorescent characteristics of fluorescein covalently attached to 3'-end of tRNAFhe and X-nucleotide in the extra arm of several species of tRNA from E . coli have been studied . The probe is shown to be a sensitive factor indicating the conformational change of tRNA induced by Mg2+ and Na+ ions . By measuring the extent of energy transfer the distances between the fluorescent probe attached to 3'-terminus and X-nucleotide of tRNA and specific binding site of ethidium bromide on tRNA were determined to be 40.5 A and 32.5 A, respectively . The distances measured are in good agreement with the NMR spectroscopy data showing that the specific binding site for ethidium bromide on tRNA is localised near the sixth base pair of the acceptor stem. Mol Biol (Mosk), 1978 Mar-Apr, 12(2), 327 - 33 {Template properties of the decadeoxynucleotide d(pCCACGAAACC) in the RNA polymerase system of Escherichia coli}; Badashkeeva AG et al.; The decadeoxynucleotide d(pCCACGAAACC) transcription by E . coli RNA-polymerase was studied . The transcript was shown to be several times longer than the template . The oligonucleotide GpGpGpGpUp complementary to the "contact" of two neighbouring template molecules was found in the pancreatic RNase digest of the RNA-product . This fact is consistent with our hypothesis reported recently . Pentanucleotide d(pGGTTT) may funtion as a primer in the decadeoxynucleotide transcription being incorporated into RNA. J Antibiot (Tokyo), 1978 Mar, 31(3), 229 - 36 Kinetic studies of ampicillin action on Escherichia coli and their spheroplasts; Elkhouly AE et al.; Kinetic studies of ampicillin action were made on exponentially growing Escherichia coli and on E . coli-spheroplasts using a range of inhibitory and subinhibitory concentrations of ampicillin . For each concentration, the value (ko--ka) representing the difference in generation rates of ampicillin-free culture (ko) and the generation rate of the culture with ampicillin (ka) was calculated and plotted against ampicillin concentration . A straight line relation was obtained with E . coli cells, its intersection with the abscissa, where (ko--ka) = o, give the concentration of ampicillin which exerts no inhibitory action on the cells (0.25 microgram/ml) . When ka was plotted against ampicillin concentration, the relation was also linear . Its intersection with the abscissa gives the minimum lethal concentration of ampicillin on the bacterial cells (1.05 microgram/ml) . With E . coli-spheroplasts such plots were non-linear which means that a different order of reaction was involved.This difference is probably due to a different mechanism of ampicillin action as revealed by the electroscanning microscopy. Eur J Biochem, 1978 Mar, 84(1), 301 - 9 A study of unwinding of DNA and shielding of the DNA grooves by RNA polymerase by using methylation with dimethylsulphate; Melnikova AF et al.; The dimethylsulphate method has been used to study the complexes of RNA polymerase (Escherichia coli) with DNA of T7 phage, poly{d(A--T)} and fragments of calf thymus DNA protected against DNase digestion by RNA polymerase . The binding of RNA polymerase to DNA significantly increases the formation of 1-methyl-adenine produced by methylation of the single-stranded DNA region, diminishes by about 10% the formation of 3-methyl-adenine by methylation within the minor groove and does not affect the formation of 7-methyl-guanine by methylation within the major DNA groove . The presence of nascent RNA decreases the formation of 1-methyl-adenine in DNA of the complex by about 30% . The initiation of RNA synthesis or RNA synthesis itself does not influence the methylation of the major groove but shielding of the minor groove increases by about twice as much . These results suggest that RNA polymerase, upon binding, breaks Watson-Crick base-pairing in a DNA region of about 15-base-pairs long, that nascent RNA forms a duplex with DNA of about 10-base-pairs long; and that the enzyme weakly interacts with DNA along its grooves and preferentially makes contacts with the minor groove. Arch Microbiol, 1978 Mar, 116(3), 235 - 8 Cell yields of Escherichia coli during anaerobic growth on fumarate and molecular hydrogen; Bernhard T et al.; Escherichia coli was grown anaerobically on sodium fumarate and molecular hydrogen or sodium formate in continuous culture . The maximal growth yield and the maintenance coefficient were determined . In a mineral medium a Ymax(fum) value of 6.6 g dry weight per mol fumarate was found . This value increased to 7;5 when casamino acids were present in the medium . From these data and the corresponding Ymax(ATP) values it could be calculated that per mol of fumarate reduced, 0;4 mol of ATP became available for growth . In batch culture a Yfum value of 4.8 g dry weight per mol fumarate was determined. Nucleic Acids Res, 1978 Mar, 5(3), 905 - 24 Recombinant plasmids containing Xenopus laevis globin structural genes derived from complementary DNA; Humphries P et al.; Details are presented of the in vitro synthesis of double-stranded DNA complementary to purified Xenopus globin messenger RNA, using a combination of reverse transcriptase, fragment 'A' of E . coli DNA polymerase 1 and S1 endonuclease . After selection of duplex DNA molecules approaching the length of Xenopus globin messenger RNA by sedimentation of the DNA through neutral sucrose gradients, the 3'-OH termini of the synthetic globin gene sequences were extended with short tracts of oligo dGMP using terminal transferase . This material was integrated into oligo dCMP-extended linear pCR1 plasmid DNA and amplified by transfection of E . coli . Plasmids carrying globin sequences were identified by hybridization of 32P-labelled globin mRNA to total cellular DNA in situ, by hybridization of purified plasmids to globin cDNA in solution, by analysis of recombinant DNA on polyacrylamide and agarose gels, and by heteroduplex mapping . The results show that extensive DNA copies of Xenopus globin mRNA have been integrated into recombinant plasmids. Nucleic Acids Res, 1978 Mar, 5(3), 805 - 23 Studies on ribosome structure and interactions near the m62Am62A sequence; Thammana P et al.; Antibodies raised against N6, N6-dimethyl adenosine were used to study the environment and role of the m62Am62A sequences in the E . coli ribosome . It is observed that this sequence is exposed on the surface of isolated 30S subunits, but becomes inaccessible for IgG interaction upon heat activation . The m62Am62A sequence is also inaccessible for IgG interaction in 70S ribosomes or 30S subunits immediately after dissociation of 70S particles . The presence of IgGs results in a significant inhibition of IF3 binding to unactivated 30S particles . IF3 binding to activated 30S subunits is unaffected by the IgGs . Crosslinking of 30S proteins S18 and S21 with the bifunctional phenylene dimaleimide reagents results in a reduction in the extent of 30S-IgG interaction . From what is already known about the location of S18, S21 and the IF3 binding site, it is suggested that the m62Am62A sequence is located close to the initiator tRNA binding site of the 30S subunit during initiation of protein synthesis. Nucleic Acids Res, 1978 Mar, 5(3), 679 - 89 Preparation and properties of insolubilized restriction endonucleases; Lee YH et al.; Type II restriction endonucleases Bam HI and Eco RI were covalently coupled to Sepharose . These insolubilized enzymes generated fragment patterns for several viral DNAs identical to those produced by the respective free enzymes . Conditions for optimal activity were similar for both bound and unbound forms of the enzymes . Insolubilization improved thermal stability of Bam HI and Eco RI . The bound enzyme can be recovered from reaction mixtures and reused several times . Upon storage at 4 degrees C, coupled endonucleases remained stable for several months. Med Hypotheses, 1978 Mar-Apr, 4(2), 165 - 72 Does ambient ozone pose a serious public health concern as a widespread environmental mutagen? Yao JS, Calabrese EJ, DiNardi SR. Based on bacterial, plant, animal and human studies, it is evident that O3 is a general mutagen . However, there is still considerable uncertainty as to the extent to which O3 is a human mutagen . Attempts to develop dose-response relationships have not yielded consistent results in the several studies thus far reported . At the present time there is a complete lack of data concerning human responses from ambient exposure . In light of the extent of the photochemical oxidant problem in the U.S . and the potential genetic effects of O3, it is suggested that a major research effort be directed at both the elucidation of the potential mutagenic effects of O3 as well as the implementation of effective oxidant control strategies. J Pharm Sci, 1978 Mar, 67(3), 407 - 9 Synthesis and biological activities of 10-substituted benzo{b}{1,5}naphthyridines; Sinha BK et al.; Eight 10-substituted benzo{b}{1,5}naphthyridine derivatives containing N-(pyrrolidino)alkylamines, methanesulfonanilides, and aminoacetanilides were prepared, and their binding with DNA was studied by (a) Tm measurements and (b) the effect on DNA-dependent RNA polymerase in vitro . In addition, they were evaluated as antineoplastic agents in the P-388 test . None of the compounds exhibited anti-cancer activity. J Bacteriol, 1978 Mar, 133(3), 1543 - 5 Ribonuclease III is involved in motility of Escherichia coli; Apirion D et al.; Mutants of Escherichia coli deficient in ribonuclease III are nonmotile . All transductants and revertants that regained ribonuclease III also regained motility, and all transductants that remained or became rnc are nonmotile, although only some of the revertants that regained motility also became ribonuclease III+. J Bacteriol, 1978 Mar, 133(3), 1533 - 5 Phospholipid turnover during the division cycle of Escherichia coli; Zuchowski C et al.; The turnover of phospholipids in Escherichia coli B/r was analyzed in synchronously growing populations . The turnover of presynthesized phosphatidyl-glycerol and cardiolipin continued at a constant exponential rate throughout the division cycle. J Bacteriol, 1978 Mar, 133(3), 1524 - 6 Mutations affecting the citrate-dependent iron uptake system in Escherichia coli; Woodrow GC et al.; Isolation of six strains of Escherichia coli K-12 carrying mutations affecting the citrate-dependent iron uptake system is described . Genetic analysis of these mutants showed that the mutation affecting the citrate system are cluster together at about min 6 on the E . coli chromosome. J Bacteriol, 1978 Mar, 133(3), 1520 - 3 Method for the genetic labeling of cryptic plasmids; So M et al.; A recently developed method for detecting transposition was employed to genetically "label" conjugative plasmids such as F and Ent P307, which do not normally exhibit a readily identifiable phenotype. J Bacteriol, 1978 Mar, 133(3), 1457 - 66 Translation of the leader region of the Escherichia coli tryptophan operon; Miozzari GF et al.; When the trp operon of Escherichia coli contains either of two deletions that fuse the initial portion of the leader region to the distal segments of the trpE gene, novel fusion polypeptides are produced . The new polypeptides are synthesized efficiently both in vivo and in vitro, and their synthesis is subject to repression by trp repressor . Fingerprint analyses of tryptic and chymotryptic digests of the new polypeptides show that both contain trpE polypeptide sequences and, despite their different sizes, share the same N-terminal sequence . Our results suggest that synthesis of the new polypeptides is initiated at the AUG-centered ribosome-binding site in the leader region and proceeds in phase to the region coding for the C-terminal end of the trpE polypeptide. J Bacteriol, 1978 Mar, 133(3), 1444 - 51 Proteins synthesized in minicells containing plasmid ColE1 and its mutants; Inselburg J et al.; Minicells containing the ColE1 plasmid and derivatives of it that contain a Tn3 insertion and deletions of the plasmid were shown to synthesize a variety of polypeptides: (i) a 56,000-dalton polypeptide was found that is colicin E1 . (ii) A 15,000-dalton polypeptide is involved in plasmid DNA relaxation . (iii) A 14,000-dalton polypeptide may be the colicin immunity protein . (iv) A correlation between the location of various Tn3 insertions and the proteins synthesized from the plasmid DNA was found that suggests the locations of promoter sites in the plasmid and directions of transcription in two regions of the plasmid . (v) Polypeptides associated with the presence of Tn3 were identifiable . (vi) The nature and extent of gene expression of deletion mutants only generally correlates with the extent of the deletions. J Bacteriol, 1978 Mar, 133(3), 1383 - 92 Assignment of tra cistrons to EcoRI fragments of F sex factor DNA; Achtman M et al.; We describe here the cloning of single EcoRI fragments from the tra region of F DNA using ColE1::Tn3 as vector . These plasmids, as well as the series of Skurray et al . (Proc . Natl . Acad . Sci . U.S.A . 73:64-68, 1976), have been used to refine the map positions of tra cistrons on the F factor as well as to define a new DNA transfer cistron, traM . The current map of the tra cistrons is presented . None of the known tra cistrons, with the exception of traG, straddles an EcoRI site . The EcoRI site at 82 kilobases splits the traG cistron into two portions, an operator-proximal portion necessary for F pilus synthesis and an operator distal portion involved in conjugation itself . The operon structure of the tra cistrons was reevaluated, and we found that traI is at least partially independent of transcription of the traA to traD operon. J Bacteriol, 1978 Mar, 133(3), 1351 - 7 In vitro synthesis of cystathionine gamma-synthetase in Escherichia coli K-12; Krueger JH et al.; Synthesis of cystathionine gamma-synthetase directed by DNA from a lambdadmet transducing phage has been achieved in cell extracts from Escherichia coli K-12 . Enzyme synthesis was stimulated two- to threefold by the addition of guanosine 3'-diphosphate 5'-diphosphate to the incubation mixtures . Kinetic studies showed a 1.5- to 2.0-min lag between initiation of transcription and completion of a translatable message . This lag is shorter than that observed for beta-galactosidase synthesis with DNA from a lac transducing phage known to initiate transcription at the lac promoter . This result, together with information on the structure of the transducing phage, shows that pL is not used for initiation of in vitro metB transcription . Attempts to demonstrate repression were not successful, and unexpectedly, extracts from metJ+ strains were found to be more effective at enzyme synthesis than those from their metJ derivatives. J Bacteriol, 1978 Mar, 133(3), 1278 - 81 Analysis of cell division in single clones of the Escherichia coli K-12 lexA mutant; Howe WE et al.; The growth of clones of lexA mutant and lexA+ cells was analyzed . During normal growth lexA mutant clones frequently divided early, producing smaller newborn cells than the lexA+ clones . Some newborn cells in the lexA clones did not elongate or divide at all, a response that was never observed in the lexA+ clones . When starved for thymidine, most of the lexA mutant clones elongated and subsequently divided . The majority of lexA+ clones also elongated but did not divide . The above results suggest that one of the functions of the lexA+ gene is coordination of DNA repair with cell division. J Bacteriol, 1978 Mar, 133(3), 1273 - 7 Pyridoxine-requiring mutants of Escherichia coli: glycolaldehyde dehydrogenase is not coded for by the pdxB gene; Shimizu S et al.; Twenty-seven independent pyridoxineless mutants belonging to genetic linkage group I were assayed for glycolaldehyde dehydrogenase . Some mutants lacked enzyme activity entirely, and others showed activity ranging from very low to wild-type levels . Reversion to pyridoxine independence usually had no effect upon this activity . Transfer of the pyridoxine genes to a common host that had wild-type levels of enzyme activity made the recipient pyridoxineless without affecting the activity . These results negate the idea of an obligatory role for glycolaldehyde dehydrogenase in pyridoxine biosynthesis. J Bacteriol, 1978 Mar, 133(3), 1197 - 202 Isolation of an Escherichia coli K-12 dnaE mutation as a mutator; Konrad EB; Using a papillation method, a large number of Escherichia coli K-12 mutator mutations have been isolated . Only one of these (out of 1,250) mutator mutations has proved to be conditionally lethal at high temperatures . In vivo complementation tests indicated that this mutation, dnaE9, lies in dnaE, the structural gene for DNA polymerase III . The dnaE9 polymerase was not thermolabile in vitro; however, it showed a slow decline in specific activity in vivo at the nonpermissive temperature . Cultures of this mutant exhibited a comparably slow shutoff of DNA synthesis on shift to a nonpermissive temperature . dnaE9 showed temperature-sensitive mutator activity, which is not dependent on recA. J Bacteriol, 1978 Mar, 133(3), 1150 - 5 Role of glutathione in reversing the deleterious effects of a thiol-oxidizing agent in Escherichia coli; Hibberd KA et al.; Diamide was found to be much less specific for the oxidation of glutathione in vivo in Escherichia coli than had been previously assumed . In vivo, only a slight alteration of the ratio of reduced to oxidized glutathione was found, whereas a significant amount of glutathione was found in the form of mixed disulfide with proteins . This latter occurrence was postulated as being responsible for the bacteriostatic effect of diamide. J Bacteriol, 1978 Mar, 133(3), 1108 - 12 Periplasmic localization of nicotinate phosphoribosyltransferase in Escherichia coli; Baecker PA et al.; Nicotinate phosphoribosyltransferase (NAPRTase) in Escherichia coli mediates the formation of nicotinate mononucleotide, a direct precursor of nicotinamide adenine dinucleotide (NAD), from nicotinate and 5-phosphoribosyl-1-pyrophosphate . Specifically, NAPRTase contributes to NAD synthesis by utilizing intracellular nicotinate formed from NAD degradation products, which are recycled by NAD cycle enzymes and exogenous nicotinate when it is available . In previous studies, it has been tacitly assumed that almost all NAD cycle enzymes are localized in the cytoplasm of E . coli . The results of this investigation provide evidence that NAPRTase is a periplasmic (extracytoplasmic) enzyme . The osmotic shock of exponential-phase cells of E . coli K-12 and ML 308-225 resulted in the release of 63 to 72% and 42 to 48%, respectively, of the NAPRTase into the shock medium . In addition, when exponential cells of strains K-12 and ML 308-225 were converted into spheroplasts, 75 to 84% and 54 to 68%, respectively, of the enzyme was released into the spheroplast medium . Since previous estimates of the effective levels of NAPRTase present in putative repressed and derepressed E . coli cells appeared to be very low, a more convenient and accurate alternative method for the evaluation of NAPRTase in whole cells was developed . The results show that NAPRTase is subject only to a modest degree of enzyme repression . In addition, no evidence was found for the presence of a protein or low-molecular-weight inhibitor of the enzyme in repressed cells. J Bacteriol, 1978 Mar, 133(3), 1062 - 5 Effect of R-plasmid RP1 and nutrient depletion on the gross cellular composition of Escherichia coli and its resistance to some uncoupling phenols; Gilbert P et al.; The resistance of Escherichia coli batch cultures depleted of carbon (C-dep), magnesium (Mg-dep), or phosphate (P-dep) against low concentrations of 3-chlorophenol, 4-chlorophenol, or 2-phenoxyethanol varied . C-dep cultures were always significantly more sensitive than Mg-dep or P-dep cultures . The presence of R-plasmid RP1 increased the sensitivity of C-dep cultures to 3- and 4-chlorophenol, yet had little effect on those cultured depleted in magnesium or phosphate ions . Cultures with R-plasmid RP1 had increased levels of beta-polyhydroxybutyrate irrespective of the nature of the depleting nutrient . P-dep bacteria had less than one-third of the phospholipid of other cell types, this deficiency being compensated for by increases in fatty acid and neutral lipid content . The reduction in phospholipid content of P-dep cultures was entirely accounted for by decreased diphosphatidylglycerol and phosphatidylethanolamine levels in these cells. J Bacteriol, 1978 Mar, 133(3), 1053 - 61 DNA replication pattern and cell wall growth in Escherichia coli PAT 84; Koppes LJ et al.; An electron microscopic radioautographic study was made of tritiated thymidine incorporation into the genome of Escherichia coli PAT 84 and of tritiated meso-D,L-2,6-diaminopimelic acid (DAP) into the cell envelope . Pulse-labeled cells growing at 30 degrees C with a doubling time of 170 min were classified according to length by the method of agar filtration . Mathematical analysis of the length distribution led to the assumption of an exponential relation between length and time . A novel DNA replication pattern was found . Within the cell cycle DNA replication terminates at 70 min; then a gap follows of 64 min, after which DNA replication is initiated at 134 min . Thus, the C period is 106 min and the D period is 100 min . Cell constriction starts at 141 min and coincides with initiation of DNA replication . Detailed quantitative analysis of the {3H}thymidine grain frequency distribution allowed the distinction of three groups of cells . The first group incorporated no label, the second group an amount C, and the third group an amount 2 X C . The relative contribution of each group to a particular length class was determined . The data fitted very well into the DNA replication pattern . The same analysis was carried out on DAP pulse-labeled cells . Again, three groups of cells could be distinguished, and their relative contributions to each length class was determined . The group with the double amount of label was especially prominent at the end of the cell cycle . The emergence of this group might represent the acquisition of new lateral growth areas. Infect Immun, 1978 Mar, 19(3), 919 - 22 Platelet aggregation in rabbits made tolerant to endotoxin; Walker RI et al.; Endotoxin may cause abnormal deposition of platelet-endotoxin aggregates, and this event could have damaging effects . We compared the aggregation characteristics of platelets from rabbits made tolerant to the lethal effects of endotoxin with those of platelets from normal rabbits . Platelets from tolerant rabbits aggregated more rapidly (greater than 90 s faster) in the presence of endotoxin than did platelets from nontolerant animals . Furthermore, platelets from tolerant animals aggregated reversibly . These characteristics of platelets from tolerant animals are due to humoral factors in the plasma, because 1:1 dilution of normal platelet-rich plasma with plasma from tolerant rabbits caused the normal platelets to behave like those from tolerant animals . Survival after challenge with lethal quantities of endotoxin was enhanced in tolerant rabbits; this may be due to promotion of more efficient removal of endotoxin-platelet complexes from the blood by the reticuloendothelial system. Infect Immun, 1978 Mar, 19(3), 883 - 8 Differences in serological responses and excretion patterns of volunteers challenged with enterotoxigenic Escherichia coli with and without the colonization factor antigen; Evans DG et al.; Double-blind studies were performed to compare the virulence of enterotoxigenic Escherichia coli with and without the fimbriate colonization factor antigen (CFA), using young healthy adults (mean age, 23 years) as volunteers . In the first study one group of volunteers ingested 1 X 10(6) E . coli H-10407, the CFA-positive strain, and another group ingested 1 X 10(6) E . coli H-10407-P, the CFA-negative spontaneous derivative of strain H-10407 . The second study was similar except that the test strains were administered at a dose of 1 X 10(8) viable cells . Three parameters of infection were monitored: (i) diarrhea and associated symptoms; (ii) excretion pattern of test strains; and (iii) humoral antibody response to CFA, somatic antigen, and heat-labile enterotoxin . Significant signs of illness occurred only in six of seven volunteers who ingested E . coli H-10407 at a dose of 1 X 10(8) . At both doses, E . coli H-10407-P appeared in the stool on day 1 postchallenge and disappeared by day 4 . In contrast, strain H-10407 was persistently excreted from the first to the last day of the study . Also, only those volunteers in the H-10407 challenge groups (12 of 13 analyzed) responded with a fourfold antibody titer rise to CFA, somatic antigen, and/or heat-labile enterotoxin . No reversion of H-10407-P to H-10407 was detected. Infect Immun, 1978 Mar, 19(3), 779 - 84 Characterization of a partially purified methanol-soluble heat-stable Escherichia coli enterotoxin in infant mice; Mullan NA et al.; While studying the involvement of cyclic adenosine 3',5'-monophosphate (cAMP) in the fluid secretion caused by heat-stable enterotoxin (ST) from Escherichia coli P16 in infant mice, it was noted that the culture filtrate containing ST also contained large amounts of cAMP . The present paper details attempts to obtain a cAMP-free ST preparation . The organisms were grown in a defined medium, and the heated culture filtrate was concentrated by reverse osmosis . After methanol extraction of the filtrate, which removed 80% of the nonactive solids, the methanol-soluble ST was further purified by gel filtration through a Sephadex G-10 column . The first fraction recovered after gel chromatography contained ST with a negligible amount of cAMP . Treatment with methanol did not adversely affect the enterotoxic activity . Certain parameters of the infant mouse model have been investigated, and using our ST preparation it has been found that animals remain responsive up to 15 days of age with an optimum assay time of 2 h after toxin challenge. Infect Immun, 1978 Mar, 19(3), 1097 - 8 Isoelectric point of cell-free K99 antigen exhibiting hemagglutinating properties; Morris JA et al.; The isoelectric point of the K99 antigen in partially purified preparations isolated from Escherichia coli B41 was 4.2 . Electrofocused K99 antigen hemagglutinated guinea pig and sheep erythrocytes and gave a single precipitin line on diffusion against antisera to E . coli B41 and absorbed factor K99 antisera. Can J Biochem, 1978 Mar, 56(3), 181 - 9 A DNA endonuclease isolated from yeast nuclear extract; Bryant DW et al.; We have isolated and partially purified a DNA endonuclease from nuclei of the yeast Saccharomyces cerevisiae . Although purified on the basis of its ability to degrade denatured DNA, the enzyme can also attack native DNA . Denatured oligonucleotide products of the enzyme are sensitive to venom phosphodiesterase (EC3.1.4.1.) but not to bovine spleen phosphodiesterase (EC3.1.4.18) . The enzyme has an estimated molecular weight of 6.6--7.5 X 10(4), more than twice as large as the endonucleases involved in DNA repair in Escherichia coli . When analyzed on glycerol gradients, the endonuclease sedimented as a single activity against both denatured DNA and closed circular DNA duplexes . The enzyme showed a 10-fold preference for denatured over native T7 DNA substrate, and appears to produce random nicks in a supercoiled replicative form of phiX174 DNA (RFI) with no discernable preference for the unpaired bases in the supercoiled duplex . The endonuclease appears to be distinct from the yeast endonucleases previously described. Arch Pathol Lab Med, 1978 Mar, 102(3), 140 - 5 Malakoplakia in ulcerative colitis; MacKay EH; Classic malakoplakia was found in the colon of a patient with a 30-year history of proven ulcerative colitis . She had undergone total proctocolectomy after failure of medical treatment to control her illness . Immunoperoxidase studies showed immunoglobulins and muramidase within the malakoplakic histiocytes, and electron microscopy showed bacteria resembling Escherichia coli in the same cells . Immunologic studies on the patient showed an unusually high E coli antibody titer (1:512) in her serum and reduced numbers of circulating T-lymphocytes with reduced cytotoxic activity . This case shows the paradoxical rarity of malakoplakia in ulcerative colitis and reaffirms the presence of an immunologic defect that may be pathogenetically significant. J Infect Dis, 1978 Mar, 137(3), 292 - 7 A prospective study of enteropathogenic Escherichia coli in endemic diarrheal disease; Gurwith M et al.; The rate of isolation of Escherichia coli belonging to the traditional serotypes enteropathogenic for infants was studied prospectively in two groups . Group 1 consisted of children with diarrhea and of controls without gastrointestinal disease who were matched for age and inpatient or outpatient status . Group 2 consisted of families entered in a prospective study of rotavirus infections . In group 1 enteropathogenic Escherichia coli were found in 13 (6%) of 220 children younger than 12 months of age and in nine (6%) of 143 children 12--35 months of age, all of whom had diarrhea . Enteropathogenic E . coli were found in only one of an equal number of matched controls (P = 0.002 and 0.004, respectively) . In group 2 enteropathogenic E . coli were present in seven (18%) of 38 specimens obtained during diarrheal episodes, as compared with five (1%) of 492 specimens obtained when there was no diarrhea (P less than 0.001) . The enteropathogenic E . coli isolated were not enterotoxigenic . The most common serogroup was O111, but many different O:H serotypes were detected . Thus, the association of enteropathogenic E . coli with endemic diarrhea was significant, even though no enteropathogenic mechanism was apparent. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1490 - 4 Chromosomal integration of phage lambda by means of a DNA insertion element; MacHattie LA et al.; Phage lambdacam112, which contains the chloramphenicol resistance transposon Tn9 and has a deletion of attP and the int gene, will lysogenize Escherichia coli K-12 . Prophage integration occurs at different chromosomal sites, including lacY and malB, but not at attB . All lambdacam112 prophages are excised from the chromosome after induction but with various efficiencies for different locations . Heteroduplex analysis of lambdaplacZ transducing phages isolated from a lacY::lambdacam112 prophage reveals an insertion sequence 1 (IS1) element at the joint of viral and chromosomal DNA . Two lines of evidence indicate that lambdacam112 encodes an excision activity that recognizes the IS1 element: (i) prophage derepression increases the frequency of excision from lacY to yield lac+ revertants, and (ii) lambdacam112 infection increases reversion of a galT::IS1 mutation about 50-fold . Our results indicate that the IS1 termini of TN9 can replace attP as a site for lambda insertion in the bacterial chromosome and that excision events are catalyzed by an IS1-encoded protein under lambda repressor and N gene control. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1289 - 93 DNA polymerase activities in differentiating mouse neuroblastoma N-18 cells; Bhattacharya P et al.; The activities of two DNA polymerases (DNA nucleotidyltransferases) were characterized in mouse neuroblastoma clone N-18 on the basis of their apparent molecular weights (determined by sucrose density gradient centrifugation: polymerase-alpha, 7.5-8 S; polymerase-beta, 3-4 S) and relative inhibition by sulfhydryl-blocking agents . N-Ethylmaleimide (10 mM) and iodoacetamide (1.5 mM) inhibited DNA polymerase-alpha activity completely, whereas only 35-40% inhibition was observed for DNA polymerase-beta under similar conditions . DNA polymerase-alpha activity was reduced 50-70% in N-18 cells that had been induced to differentiate by 4 micro M bromodeoxyuridine, and the low molecular weight DNA polymerase-beta activity remain unchanged . With activated calf thymus DNA as template, only DNA polymerase-alpha activity was stimulated in the presence of added ribonucleotides and purified Escherichia coli RNA polymerase. Endocrinology, 1978 Mar, 102(3), 947 - 53 Evidence that the hypothalamus mediates endotoxin stimulation of adrenocorticotropic hormone secretion; Yasuda N et al.; The site of action of Escherichia coli endotoxin in inducing ACTH secretion was studied in vivo and in vitro . Hypophysectomized rats, bearing two to three transplanted pituitaries under the kidney capsule and "primed" with exogenous ACTH, responded to 2.0-7.5 microgram/100 g BW ip or iv endotoxin with a several-fold increase of plasma corticosterone . This response was markedly reduced by hypothalamic lesions and completely abolished by removing the entire forebrain . Endotoxin added directly to cultured rat adenohypophyseal cells in a concentration up to 10 microgram/ml did not induce significant ACTH secretion . We conclude that endotoxin-induced ACTH secretion from heterotopically transplanted pituitaries is mediated primarily by the hypothalamus, presumably through hypothalamic CRF that reaches the transplanted pituitaries via the systemic circulation. Tsitologiia, 1978 Mar, 20(3), 251 - 63 {Poly (ADP-ribose), ADP-ribosylation of proteins and regulation of cell activity}; Nemchinskaia VL et al.; The nature of a before unknown biological activity of NAD as a substrate in protein modification reaction is considered . Upon enzymatic digestion of NAD its adenosinediphosphate ribose (ADPR) part is transferred to acceptor proteins . ADPR in its mono- or polymeric form is covalently linked to proteins at the expense of NAD's high energy bound . Negatively charged ADPR, in association with a protein, is able to alter the charge, conformation and biological activity of the latter . The reaction is important in structural rearrangements of chromatin, in the synthesis and repair of DNA, in cell growth and differentiation and in the mechanisms of actions of actions of bacterial toxins. Cell, 1978 Mar, 13(3), 573 - 80 Formation of Okazaki fragments in polyoma DNA synthesis caused by misincorporation of uracil; Brynolf K et al.; When dUTP replaced dTTP during polyoma DNA replication in isolated cell nuclei, radioactivity from labeled deoxynucleoside triphosphates was almost exclusively recovered in very short Okazaki fragments and incorporation ceased after a short time . Addition of uracil, a known inhibitor of the enzyme uracil-DNA glycosidase (Lindahl et al., 1977), increased total synthesis and shifted the incorporation to longer progeny strands . The presence of as little as 2.5% of dUTP in a dTTP-containing system gave a distinct increase in isotope incorporation into Okazaki pieces accompanied by a corresponding decrease in longer strands . This effect was reversed completely by uracil . The short strands formed from dUTP could be chased efficiently into long strands . Our results suggest that dUTP can be incorporated in place of dTTP into polyoma DNA, and that polyoma-infected nuclei, similar to E . coli (Tye et al., 1977), contain an excision-repair system which by removal of uracil causes strand breakage and under certain circumstances may contribute to the formation of Okazaki fragments. J Antibiot (Tokyo), 1978 Mar, 31(3), 192 - 201 Two kinds of mutants defective in multiple carbohydrate utilization isolated from in vitro fosfomycin-resistant strains of Escherichia coli K--12; Tsuruoka T et al.; Two types of in vitro fosfomycin-resistant mutants defective in multiple carbohydrate utilization were selected from Escherichia coli strain K--12 . One mutant, FR182, was defective in phosphoenolpyruvate: sugar phosphotransferase system and the ability to form adenosine 3',5'-cyclic monophosphate (cAMP) was lowered . Another mutant, FR190, was defective in cAMP formation . Restoration by cAMP of fosfomycin (FOM) sensitivity coupled with recovery of utilization of many carbohydrates including sn-glycerol-3-phosphate (G-3-P) was observed in both of the resistant mutants . FOM was not taken up by these resistant strains but, in the cells cultured in the presence of cAMP, accumulation of FOM was equivalent to that of the sensitive parent strain . Decreased uptake of G-3-P was also restored in both of the resistant strains cultured in the presence of cAMP . These results indicate that the resistance to FOM in these mutants is due to impairment of G-3-P transport system, one of the pathways for uptake of FOM . They were sensitized to FOM by D-glucose-6-phosphate because of the induction of hexose phosphate transport system, another uptake pathway. Can J Microbiol, 1978 Mar, 24(3), 203 - 8 Growth of Escherichia coli on glucosamine 6-phosphate: selection of a constitutive hexose phosphate transport system mutant; Dietz GW Jr; Glucosamine 6-phosphate was found to be a substrate but not an inducer for the hexose phosphate transport system of Escherichia coli . Wild-type cells grow very poorly on glucosamine 6-phosphate . A mutant was selected that will grow rapidly on glucosamine 6-phosphate because it contains a constitutive hexose phosphate transport system. Nucleic Acids Res, 1978 Mar, 5(3), 861 - 77 Properies of tRNAPhe from yeast carrying a spin label on the 3'-terminal . Interaction with yeast phenylalanyl-tRNA Synthetase and elongation factor Tu from Escherichia coli; Sprinzl M et al.; The 2-thioketo function of tRNAPhe-C-s2C-A in which the penultimate cytidine residue is replaced by 20thiocytidine can serve as a site of specific attachment of spin label . By alkylation of tRNAPhe-C-s2C-A with iodoacetamide or its spin label derivatives tRNAPhe-C-(acm)s2C-A or tRNAPheC-(SL)s2C-A are formed . The enzymatic phenylalanylation of these tRNAsPhe revealed that the 2-position of the penultimate cytidine can be modified without impairing this enzymatic reaction but there exists a sterical limitation for the subsituent on this position beyond which the tRNAPhe:phenylalanyl-tRNA synthetase recognition is not possible . Both Phe-tRNAPhe-C-(acm)s2C-A as well as Phe-tRNAPhe-C(SL)s2C-A form ternary complexes with EF-Tu.GTP . The part of the 3'-terminus of tRNAPhe where the additional substituents are attached is therefore not involved in the interaction with this elongation factor . This could be also demonstrated by ESR measurements of spin labelled tRNAsPhe . The correlation times, tauc, for tRNAPhe-C-(SL)s2C-A, Phe-tRNAPhe-C-(SL)s2C-A and Phe-tRNAPhe-C-(SL)s2C-A.EF-Tu:GTP are essentially identical indicating that the structure of the 3'-end of tRNAPhe is not influenced significantly by aminoacylation or ternary complex formation. J Virol, 1978 Mar, 25(3), 940 - 3 Transcription of BK virus DNA by Escherichia coli RNA polymerase: size and sequence analysis of RNA; Meneguzzi G et al.; Transcription of human papovarirus BK superhelical DNA by Escherichia coli RNA polymerase yielded symmetric RNA with an average chain length of 1,3000 nucleotides . All regions of human papovavirus BK DNA were equally transcribed . At least four initiation sites were available to the procaryotic enzyme. Cell, 1978 Mar, 13(3), 551 - 63 Conservation of the primary structure at the 3' end of 18S rRNA from eucaryotic cells; Hagenbuchle O et al.; DNA sequencing methods have been used to determine a sequence of about 20 nucleotides at the 3' termini of various 18S (small ribosomal subunit) RNA molecules . Polyadenylated rRNA was first synthesized using the enzyme ATP:polynucleotidyl transferase from mainze . Then in the presence of an oligonucleotide primer uniquely complementary to the end of each adenylated rRNA, a cDNA copy was produced using AMV reverse transcriptase . In every case, the cDNA transcript was of finite size, which we ascribe to the appearance of an oligonucleotide containing m62A near the 3' end of the 18S rRNAs . Sequences at the 3' termini of 18S rRNA molecules from the four eucaryotic species examined here (mouse, silk worm, wheat embryo and slime mold) are highly conserved . They also exhibit strong homology to the 3' end of E . coli 16S rRNA . Two important differences, however, are apparent . First, the 16S sequence CCUCC, implicated in mRNA binding by E . coli ribosomes, is absent from each eucaryotic rRNA sequence . Second, a purine-rich region which exhibits extensive complementarity to the 5' noncoding regions of many eucaryotic mRNAs appears consistently. J Exp Med, 1978 Mar 1, 147(3), 800 - 13 Immunologic responsiveness of the C3H/HeJ mouse: differential ability of butanol-extracted lipopolysaccharide (LPS) to evoke LPS-mediated effects; Goodman MG et al.; The lipopolysaccharide (LPS)-protein complex extracted from the cell wall of Escherichia coli K235 by the butanol-water technique has been shown to evoke a mitogenic response in bone marrow-derived (B) lymphocytes from the C3H/HeJ mouse strain . These mice are resistant to the effects of LPS extracted with phenol . Therefore, the ability of butanol-extracted LPS to modulate a spectrum of C3H/HeJ B-cell functions was investigated . Both butanol-extracted (LPS-B) and phenol-extracted (LPS-P) LPS preparations activated responder C3H/St spleen cell cultures to polyclonal antibody production, while only LPS-B activated C3H/HeJ spleen cells . Both LPS-P and LPS-B acted as adjuvants when injected after aggregated human gamma globulin (HGG) in C3H/St mice, but neither preparation was effective as a adjuvant in C3H/HeJ mice . LPS-P injected with deaggregated HGG (tolerogen) into LPS-sensitive mice has been shown previously to inhibit the induction of tolerance HGG . In the present studies, it was shown that LPS-B, but not LPs-p, was able to inhibit tolerance induction to HGG in the C3H/HeJ, whereas both preparations were effective in the C3H/St . LPS has also been shown to bypass tolerant T cells in LPS-sensitive mice late in tolerance to HGG at a time when B cells are responsive . However, in the C3H/HeJ, neither LPS-B nor LPS-P was capable of this function . The responsiveness of these B cells to HGG was demonstrated in transfer experiments . Thus, in the C3H/HeJ, LPS-B stimulates mitogenesis, polyclonal B-cell activation, and inhibition of tolerance induction, but cannot act as an effective adjuvant or as a bypass mechanism to activate B cells in the presence of tolerant T cells . The explanation for this pattern of responses may be attributable to yet another cellular defect in the C3H/HeJ mouse. Biokhimiia, 1978 Mar, 43(3), 446 - 52 {Acetate kinase chromatography on agarose derivatives}; Karpavichene DP et al.; Acetate kinase from E . coli K-12 was studied chromatographically on omega-aminoalkyl polysacharide sorbents . The dependence of the protein sorption-desorption on ionic strength and the effect of pH on the acetate kinase sorption were studied . The increase in the ionic strength caused a decrease in the amount of protein sorbed on the hexamethylenediamine- and chlorotriasinehexamethylenediamine sepharoses . On hexamethylenediamine-, octamethylenediamine- and dimethylhexamethylenediamine agaroses acetate kinase was adsorbed within the pH range of 6.5-9.0, whereas on the chlorotriasinehexamethylenediamine sepharose--at pH 6.5-8.0 . The active protein was eluted at ionic strength of 0.14-0.17 M . Acetate kinase was not adsorbed on the carboxypropyonylaminohexyl sepharose within the pH range studied, i.e . 5.0-9.0 and was not adsorbed on hexamethylenediamine agarose at pH 4.0 and on chlorotriasinehexamethylenediamine sepharose--at pH 9.0 . The mechanism of the enzyme-adsorbent interaction is discussed. Proc Natl Acad Sci U S A, 1978 Mar, 75(3), 1126 - 30 Minichromosome from BK virus as a template for transcription in vitro; Meneguzzi G et al.; BK virus DNA can be extracted from virions as a nucleoprotein complex containing about 20 nucleosomes . Transcription of this "minichromosome" with Escherichia coli RNA polymerase indicates that both initiation and elongation of RNA chains are reduced by the presence of nucleosomes . Hybridization analysis of RNA made on the complex shows preferential transcription of one region of BK virus genome . No increase in strand selection is observed with respect to transcription of purified superhelical BK virus DNA. Nucleic Acids Res, 1978 Mar, 5(3), 933 - 50 Evidence that proteins S1, S11 and S21 directly participates in the binding of transfer RNA to the 30S ribosome; Fanning TG et al.; In a previous publication1 we reported that the tyrosine selective reagent, tetraitromethane, causes complete inactivation of E . coli 30S ribosomes for poly U directed non-enzymatic phe-tRNA binding . This inactivation was demonstrated to be due to the chemical modification of the protein moiety of the ribosome . We have no identified the proteins of the 30S particle inactivated by this modification . Using a method of ribosome reconstruction we have found that unmodified proteins S1, S11, and S21 are essential for the restoration of the phe-tRNA binding activity of tetranitromethane inactivated ribosomes . We propose that these three proteins are intimately involved in the 30S ribosome binding site for tRNA. Mol Biol Rep, 1978 Feb 28, 4(1), 21 - 4 Differential effect of amino acid starvation on polysome decay in Escherichia coli; Roche J et al.; In a relA+ strain of E . coli starved separately for each of four required amino acids, the intracellular concentration of polysomes decreases as a function of time in all cases: very rapidly in the absence of arginine or leucine, slowly in the absence of threonine or histidine . In a starved isogenic relA strain, the polysome level is either totally stable or else drops slowly . The decrease in the level, when it occurs, does not significantly affect the polysome size distribution . Models for polysome metabolism in amino acid starved cells are discussed. Mol Biol Rep, 1978 Feb 28, 4(1), 15 - 9 The relationship between guanosine tetraphosphate, polysomes and RNA synthesis in amino acid starved Escherichia coli; Donini P et al.; A relA+ strain of E . coli with four amino acid requirements was starved separately for each amino acid, after which the levels of polysomes, guanosine-5'-diphosphate-3'-diphosphate and the residual net synthesis of RNA were determined . The polysome level and guanosine-5'-diphosphate-3'-diphosphate production were coordinately affected by starvation for the different amino acids, whereas no correlation was found between these two parameters and residual RNA synthesis . The main conclusion stemming from these results is that guanosine-5'-diphosphate-3'-diphosphate cannot act as the sole effector molecule in stringent control of RNA synthesis. Mol Gen Genet, 1978 Feb 27, 159(3), 239 - 48 Amplification of the lactose carrier protein in Escherichia coli using a plasmid vector; Teather RM et al.; The isolation and properties of a hybrid plasmid carrying the Y gene of the lac operon of Escherichia coli are described . The lactose carrier protein, coded for by the Y gene, is readily identified upon lac operon induction in strains carrying the plasmid . The protein comprises about 15% of the cytoplasmic membrane protein synthesized in the first generation after induction, compared with a wild type strain induced under the same conditions where lactose carrier protein comprises 1.4% of the cytoplasmic membrane protein. J Biol Chem, 1978 Feb 25, 253(4), 1101 - 5 N4-Acetylcytidine . A previously unidentified labile component of the small subunit of eukaryotic ribosomes; Thomas G et al.; The nucleoside content of 18 S rRNA from rat liver is determined under conditions known to prevent the destruction of chemically labile modified nucleosides . Two base-modified nucleosides, not completely identified before, are shown to be N6-methyladenosine and 7-methylguanosine . The results further demonstrate the presence of a hitherto unidentified component of 18 S rRNA whose spectra and chromatographic properties are identical with that of N4-acetylcytidine . In addition, this compound is not detectable in 28 S rRNA nor in 16 S rRNA derived from the small ribosomal subunit of Escherichia coli . However, it appears to be conserved in the small ribosomal subunit of eukaryotes, since it is also present in yeast 17 S rRNA and chicken liver 18 S rRNA. J Biol Chem, 1978 Feb 25, 253(4), 997 - 1000 Identification of an Escherichia coli nuclease acting on structurally altered transfer RNA molecules; Ghosh RK et al.; A nuclease (RNase D) that can recognize structurally altered transfer RNA molecules has been partially purified from Escherichia coli . The enzyme acts poorly on intact tRNA and is inactive with the synthetic polyribonucleotides, poly(A), poly(U), or double-stranded poly(A).poly(U) . The enzyme requires Mg2+ for activity and is stimulated by the monovalent cations, K+ and NH4+ . The products of the reaction are 5'-mononucleotides . The molecular weight of the protein is about 60,000 as judged by Sephadex G-100 chromatography . The enzyme does not correspond to any known E . coli ribonuclease and may represent an intracellular scavenging mechanism for denatured tRNAs and other inactive RNA molecules. J Biol Chem, 1978 Feb 25, 253(4), 1095 - 110 Effects of phospholipids on L-lactate dehydrogenase from membranes of Escherichia coli . Activation and stabilization of the enzyme with phospholipids; Kimura H et al.; Membrane-bound L-lactate dehydrogenase was freed from the detergent used during purification . The detergent-free enzyme had about one-half the specific activity of the enzyme in 1.0% Tween 80, and was only partially sensitive to the specific antibody . This enzyme was activated about 3-fold with phosphatidylglycerol, cardiolipin, or a mixture of phospholipids . The phospholipid-activated enzyme had a similar Km value for L-lactate to that of the membrane enzyme and was completely inhibited by the specific antibody . On heat treatment, the phospholipid-activated enzyme was more stable than detergent-free enzyme and was as stable as membrane-bound enzyme . The alpha helical content of the enzyme increased 1.7-fold during preincubation with these lipids and the alpha helix became more stable during heat treatment than that of the detergent-free enzyme . These results suggest that the enzyme showed monomolecular dispersion in the lipid bilayer and that its conformation, including its active site and secondary structure, was different from that of the detergent-free enzyme . Phosphatidylethanolamine, dilauroyl lecithin and lecithin from egg yolk had none of the above effects on the activity or the secondary structure of the enzyme . On the other hand, mixtures of each of these lipids and cholate had essentially similar effects to phosphatidylglycerol. J Mol Evol, 1978 Feb 21, 10(4), 319 - 23 Pattern and chance in the use of the genetic code; Berger EM; The use of triplet code words in E . coli, phiX174, MS2, and rabbit globin was examined . A significant deficiency of purines in the third position of four fold degenerate codons was noted, although its significance is not understood . There has been no consistent selection against uracil in pyrimidine restricted codons . For many amino acids the choice between code words appears random, while for arginine, isoleucine, and probably glycine, distinct biases exist which can be explained in terms of tRNA availability. Biochemistry, 1978 Feb 21, 17(4), 745 - 9 Shape of protein L11 from the 50S ribosomal subunit of Escherichia coli; Giri L et al.; Protein L11 from the 50S ribosomal subunit of Escherichia coli A19 was purified by a method using nondenaturing conditions . Its shape in solution was studied by hydrodynamic and low-angle x-ray scattering experiments . The results from both methods are in good agreement . In buffers similar to the ribosomal reconstitution buffer, the protein is monomeric at concentrations up to 3 mg/mL and has a molecular weight of 16 000-17 000 . The protein molecule resembles a prolate ellipsoid with an axial ratio of 5-6:1 a radius of gyration of 34 A, and a maximal length of 150 A . From the low-angle x-ray diffraction data, a more refined model of the protein molecule has been constructed consisting of two ellipsoids joined by their long axes. Biochemistry, 1978 Feb 21, 17(4), 669 - 72 Stereochemistry of reactions catalyzed by glutamate decarboxylase; Yamada H et al.; When the decarboxylation of L-glutamic acid by the glutamate decarboxylase from Escherichia coli is carried out in D2O, the product gamma-aminobutyric acid contains a single deuterium atom . The stereochemistry of this material was established by conversion to levorotatory methyl 4-phthalimido {4(-2)H} butyrate . The dextrorotatory isomer of the latter compound was synthesized from S-{2(-2)H} glycine by a series of reactions not affecting the stereochemistry at the chiral center . Thus, the decarboxylation of glutamic acid occurs with retention of configuration . Decarboxylation of L-alpha-methylglutamic acid by this enzyme produced levorotatory gamma-aminovaleric acid and thus also occurs with retention of configuration. Biochemistry, 1978 Feb 21, 17(4), 637 - 44 Mechanism of ethanol-induced changes in lipid composition of Escherichia coli: inhibition of saturated fatty acid synthesis in vivo; Buttke TM et al.; The in vivo effects of ethanol on lipid synthesis in Escherichia coli have been examined . Under conditions which uncoupled fatty acid synthesis from phospholipid synthesis, ethanol decreased the amount of saturated fatty acids synthesized but had little effect on the selectivity of their incorporation into phospholipids . In the absence of fatty acid degradation and unsaturated fatty acid synthesis, E . coli was still able to adapt its membrane lipids to ethanol, while the inhibition of total fatty acid synthesis eliminated this response . During growth in the presence of ethanol, strain K1060 (an unsaturated fatty acid auxotroph) incorporated an increased amount of exogenous heptadecanoic acid (17:0) to compensate for the reduction in palmitic acid (16:0) available from biosynthesis . Thus, our results indicate that the reduced levels of saturated fatty acids observed in the phospholipids of E . coli following growth in the presence of ethanol result primarily from a decrease in the amounts of saturated fatty acids available for phospholipid synthesis. Biochemistry, 1978 Feb 21, 17(4), 587 - 93 Altered topography of 16S RNA in the inactive form of Escherichia coli 30S ribosomal subunits; Hogan JJ et al.; We have studied the topography of 16S RNA in the inactive form of the 30S ribosomal subunit (Ginsburg, I., et al . (1973) J . Mol . Biol . 79, 481), using the guanine-specific reagent kethoxal . Oligonucleotides surrounding reactive guanine residues were isolated and quantitated by means of diagonal electrophoresis and sequenced . Comparison of these results with experiments on active or reactivated subunits reveals the following: (1) Most of the sites which are reactive in active 30S subunits are much more reactive (average 13-fold) in inactive subunits . Upon reactivation, these sites return to a less reactive state . Thus, a reversible increase in accessibility of specific 16S RNA sites parallels the reversible loss of protein synthesis activity of 30S subunits . (2) The number of kethoxal-reactive sites in inactive subunits is about twice that of active subunits . The nucleotide sequences and locations of the additional accessible sites in inactive subunits have been determined . (3) Sites that can be located in the 16S RNA sequence are distributed throughout the RNA chain in inactive subunits, in contrast to the clustering observed in active subunits . (4) The sites of kethoxal substitution are single stranded . Yet, of the 30 sites that can be located, 23 were predicted to be base paired in the proposed secondary structure model for 16S RNA (Ehresmann, C., et al . (1975), Nucleic Acids Res . 2, 265). Biochemistry, 1978 Feb 21, 17(4), 561 - 9 Photoinduced affinity labeling of the Escherichia coli ribosome puromycin site; Jaynes EN Jr et al.; The photoincorporation of puromycin into Escherichia coli ribosomes has been studied in detail . Incorporation into protein L23 as a function of puromycin concentration follows a simple saturation curve and is specifically blocked by structural and functional analogues of puromycin, thus demonstrating that such incorporation proceeds via an affinity labeling process . Incorporation into L23 becomes more specific as the light fluence is reduced, indicating that such incorporation takes place from a native rather than light-denatured puromycin site . L23 remains the major labeled protein using ribosomes prepared by several procedures, suggesting the conservative nature of the site . In addition evidence is presented for affinity labeling of S14 and of a site in the RNA fraction of the 50S particle . Specific incorporation appears to proceed with an anomalously high quantum yield . The detailed photochemical mechanism is not understood, although 8-alkylation of purine moiety has been excluded . Incorporation is largely inhibited in the presence of thiol reagents. Biochemistry, 1978 Feb 21, 17(4), 729 - 34 Gaps in DNA induced by neocarzinostatin bear 3'- and 5'-phosphoryl termini; Kappen LS et al.; Neocarzionstatin (NCS)-induced strand breakage of DNA generates nonfunctional binding sites for the E . coli DNA polymerase I . Treatment of the NCS-nicked DNA with alkaline phosphatase at 65 degrees C prior to the polymerase reaction results in 60-100-fold stimulation of dTMP incorporation whereas in a control not treated with the drug there is only a 2-fold increase . Sites of strand scission on the NCS-treated DNA bear phosphate at the 3' termini . This conclusion is supported by the kinetics of release of inorganic phosphate from NCS-cut DNA by exonuclease III . Since our earlier work has shown that virtually all the 5' ends of the nicks caused by NCS bear phosphomonoester groupings, the 3'- and 5'- phosphoryl termini could be quantitated using alkaline phosphatase and exonuclease III . Over a wide range of drug levels the amount of inorganic phosphate released by alkaline phosphatase is approximately twice as much as that removed by exonuclease III, indicating the presence of equal amounts of 3'- and 5'- phosphoryl termini . This, taken together with other previously demonstrated effects of NCS on DNA, such as the introduction of nicks not sealable by polynucleotide ligase, the release of thymine, and the formation of a malonaldehyde type compound, suggests that NCS-induced strand breakage involves base release accompanied by opening of the sugar ring with destruction of one or more nucleosides and results in a gap bounded by 3'- and 5'- phosphoryl termini. Biochim Biophys Acta, 1978 Feb 16, 517(2), 429 - 38 Effects of polyamines and methylglyoxal bis(guanylhydrazone) on Escherichia coli ribonucleic acid polymerase and the template activity of hepatic cell nuclei in vitro; Nelson NF et al.; Escherichia coli RNA polymerase was assayed with 4 mM Mg2+ and 1 mM Mn2+ using native DNA, heat-denatured DNA, histone-nucleate and isolated rat liver nuclei as the template source . With purified DNA and either or both divalent metal ions, 0.1--5 mM amine stimulated enzyme activity . Spermidine resulted in the greatest stimulation (1.7-fold at 5 mM); whereas, spermine or methylglyoxal bis(guanylhydrazone) first stimulated, then above 3 mM inhibited, the reaction . The addition of unfractionated histone to purified DNA inhibited the reaction by 90% . The subsequent addition of amines resulted in a slight stimulation in incorporation (1.5-fold) in the range of 1--3 mM amine . Alternatively, when enzyme was combined with DNA before histone, only a 20% inhibition was observed and this could be completely prevented by 3 mM spermidine . The addition of amines to isolated nuclei resulted in marked alterations in ultrastructure and Mg2+ content; however, relatively small effects on RNA polymerase activity were observed . With the E . coli enzyme, 0.1--1.0 mM amine stimulated RNA synthesis (1.5-fold) whereas, none of the amines stimulated endogeneous activity in the absence or presence of 300 mM (NH4)2SO4. Mol Gen Genet, 1978 Feb 16, 159(2), 219 - 21 Two major groups of colicin factors: their molecular weights; Hughes V et al.; Colicin factors are thought to fall into two taxonomic groups which differ in, amongst other properties, the molecular weight of the plasmid DNA and the host range of the colicin protein . This hypothesis is supported by the plasmids found in 26 colicinogenic strains . Two small Col factors may have arisen from larger factors, judging from similarities between their colicins. Mol Gen Genet, 1978 Feb 16, 159(2), 161 - 9 A mutation that increases the activity of nonsense suppressors in Escherichia coli; Davidoff-Abelson R et al.; We have isolated a new mutation, ups, that amplifies the suppressor activity of all the nonsense suppressors we have tested so far at low but not at high temperature . The properties of ups make it a very useful tool to improve the systems of temperature sensitive suppressors thus far described . ups maps between 25 to 27 min on the E . coli genetic map (Bachmann et al., 1976) and has no suppressor activity of its own . Its effects on translational fidelity are not influenced by mutations for ribosomal drug resistance . Thus, ups is different from ram which exhibits cooperative control of translation with other ribosomal proteins . The possible functions of ups in the cell are discussed. Biochim Biophys Acta, 1978 Feb 16, 517(2), 419 - 28 Purification of RNAase II by preparative polyacrylamide gel electrophoresis; Leineweber M et al.; Purification of RNAase II to electrophoretic homogeneity is described . The exonuclease is activated by K+ and Mg2+ and hydrolyses poly(A) to 5'-AMP, exclusively as described by Nossal and Singer (1968, J . Biol . Chem . 243, 913--922) . To separate RNAase II from ribosomes, DEAE-cellulose chromatography was used . Two additional chromatographic steps give a preparation that yields 10 bands after analytical polyacrylamide gel electrophoresis . Preparative polyacrylamide gel electrophoresis resulted in a final preparation which on analytical polyacrylamide gels gives a single band . A molecular weight of 76 000 +/- 4000 was obtained from Sephadex G-200 chromatography, with three bands from sodium dodecyl sulfate (SDS) denaturation and SDS gel electrophoresis . The subunits have a molecular weight of 40 000 +/- 2000, 33 000 +/- 2000, and 26 000 +/- 1000 . The enzyme thus appears to consist of three dissimilar subunits. Biochim Biophys Acta, 1978 Feb 16, 517(2), 400 - 6 Covalent cross-linking of ribosomal RNA and proteins by methylene blue-sensitized photooxidation; Zook DE et al.; Ribosomal proteins are covalently cross-linked to ribosomal RNA by irradiation with visible light in the presence of methylene blue and O2 . Proteins S3, S4, S5 and S7 from the 30 S subunit of Escherichia coli ribosomes and L2 and L3 from the 50 S subunit are among the cross-linked proteins . S3 and S5 had not previously been identified as RNA-binding proteins. Biochim Biophys Acta, 1978 Feb 16, 517(2), 367 - 77 On the accessibility and selection of the initiator site of mRNA in protein synthesis; Nakamoto T et al.; The specificity of the cell-free system of Escherichia coli for mRNA was examined, and the "accessibility" of some natural and synthetic RNAs to the ribosomes was determined by measurement of AcPhe-tRNA and fMet-tRNA binding, AcPhe-puromycin and fMet-puromycin formation, and polypeptide synthesis . The E . coli system effectively initiates the translation of various synthetic RNAs with AcPhe-tRNA or fMet-tRNA under conditions optimal for the translation of viral RNA . Poly(A,G,U) is accessible to the ribosomes according to all of the above criteria . Poly(A,C,G,U), 23 S rRNA, R17 RNA, and MS2 RNA, on the other hand, show limited accessibility when tested for initiator tRNA binding, or for AcPhe-puromycin and fMet-puromycin formation . MS2 and R17 RNA, but not poly(A,C,G,U) and 23 S rRNA, show accessibility when measured by polypeptide synthesis . The results suggest that, except at initiator sites of natural mRNA, an RNA containing about equal amounts of all four bases is inaccessible to E . coli ribosomes for polypeptide synthesis . Rate constants obtained for fMet-tRNA binding with MS2 RNA, poly(A,G,U), and poly(C,G,U) indicate that the ribosomes do not have any special affinity for the viral RNA . Thus, the selection of the initiator site in protein synthesis may be critically determined more by the accessibility of the initiator codon than by ribosomal recognition of the site. Mol Gen Genet, 1978 Feb 16, 159(2), 191 - 202 Regulation of the deo operon in Escherichia coli: the double negative control of the deo operon by the cytR and deoR repressors in a DNA directed in vitro system; Valentin-Hansen P et al.; The synthesis of the four enzymes of the deo operon in Escherichia coli is known from in vivo experiments to be subject to a double negative control, exerted by the products of the cytR and deoR genes . A DNA-directed in vitro protein synthesizing system makes the deo enzymes (exemplified by thymidine phosphorylase) in agreement with in vivo results . Enzyme synthesis is stimulated by cyclic AMP and repressed by the cytR and deoR gene products . Repression by the cytR repressor is reversed by cytidine or adenosine in the presence of cyclic AMP, while repression by the deoR repressor is reversed by deoxyribose-5-phosphate . Assays for the presence of the cytR and deoR repressors were established by use of S-30 extracts prepared from the regulatory mutants . Dissociation constants for repressor-operator binding as well as for repressor-inducer interactions have been estimated from the results. J Am Vet Med Assoc, 1978 Feb 15, 172(4), 458 - 63 Rotavirus as a cause of diarrhea in pigs; Bohl EH et al.; A rotavirus (reovirus-like agent) was associated with diarrheal diseases occurring in 1- to 4-week-old suckling pigs in 8 herds and in weaned pigs in 2 herds . Transmissible gastroenteritis virus was also detected in 2 of these herds, as was enteropathogenic Escherichia coli in 5 herds . Morbidity was generally greater than 80% in pigs of t