Escherichia coli

Mol Biol (Mosk), 1980 May-Jun, 14(3), 575 - 85
{Gamma-anilides of nucleoside-5'triphosphates as substrates of DNA-dependent RNA-polymerase of Escherichia coli}; Grachev MA et al.; Characteristics of NTP gamma-anilidates (AnpppN) as substrates of E . coli RNA-polymerase have been studied . Michaelis constants for AnpppN are about an order of magnitude greater than those for the usual substrates, whereas the maximum rates differ but unsignificantly . AnpppA is almost completely transformed to polyA and Anppi when synthesis of polyA takes place with AnpppA as the only substrate with denatured DNA as template (reiteration system) . The AnpppA-residue is present at the 5'-terminus of RNA synthesized from AnpppA, CTP, UTP and GTP on T7 DNA template by the holo-enzyme.

Mol Biol (Mosk), 1980 May-Jun, 14(3), 558 - 67
{Comparative analysis of affinity modification of several aminoacyl-tRNA synthetases with gamma-(p-azidoanilide)-ATP}; Bulychev NA et al.; The inhibitory action of gamma-(p-azidoanilide)-ATP on the reactions of tRNA aminoacylation catalysed by several aminoacyl-tRNA synthetases was investigated . This compound was shown to be a competitive inhibitor with respect to ATP in the case of arginyl-, valyl-, isoleucyl-, leucyl-, threonyl-, phenylalanyl-tRNA synthetases of E . coli MRE-600 and tryptophanyl-tRNA synthetase of beef pancreas . The Ki value of this analog changes from 3 x 10(-5) up to 4 x 10(-3) M depending on the enzyme specificity . In the case of methionyland lysyl-tRNA synthetases from E . coli the non-competitive and mixed inhibition accordingly was observed . The activity of isoleucyl-, valyl-, leucyl-, threonyl-, phenyl-alanyl- and tryptophanyl-tRNA synthetases in the reaction of tRNA aminoacylation is decreased as a result of UV-irradiation of the enzymes in the presence of gamma-(p-azidoanilide)-ATP . ATP and aminoacids protect these enzymes against irreversible inactivation . These results confirm the affinity labelling of the substrate binding sites of these enzymes . However, the appreciable inactivation of enzymes with UV-irradiation in the presence of gamma-(p-azidoanilide)-ATP was not detected in the cases of hystidyl-, lysyl-, methionyl-, seryl-, tyrosyl- and phenylalanyl-tRNA synthetases of E . coli MRE-600 . The data obtained enable one to suggest the difference in the structure of the amino acid activating sites of different aminoacyl-tRNA synthetases.

Mol Biol (Mosk), 1980 May-Jun, 14(3), 531 - 8
{Chemical modification of phenylalanyl-tRNA synthetase and ribosomes of Escherichia coli with derivatives of tRNA-Phe carrying photoreactive groups on guanosine residues}; Vlasov VV et al.; Photoreactive derivatives of tRNAPhe (E . coli) were synthesized by alkylation of the tRNAPhe with 4-(N-2-chloroethyl-N-methylamino)benzylamine and subsequent treatment with 1.4--dinitro-5-fluorophenylazide . The derivatives are active in binding with ribosomes and phenylalanyl-tRNA synthetase when the extent of modification is lower than 3 reactive groups per tRNAPhe molecule . Under irradiation the derivatives modify exclusively the beta-subunit of the phenylalanyl-tRNA synthetase.

Mol Biol (Mosk), 1980 May-Jun, 14(3), 520 - 30
{Effect of Escherichia coli mutations affecting the transcription termination rho on the development of T-even phages}; Gintsburg AL et al.; The functionally active transcription termination factor rho is necessary for the T-even phages development . The inactivation of the factor by thermosensitive E . coli gene rho mutations results in blocking phage development . It should be noted that phages T2 and T4 require different levels of this factor's activity . The synthesis of some early proteins diminishes during factor rho inactivation and a number of proteins typical for a later stage are observed early in infection . Under the conditions of the factor rho being inactivated the synthesis of a number of proteins is weakened late in infection and the capside proteins maturation is impaired . Alongside with this the factor rho inactivation results in a sharp decrease of phage DNA replication in infected cells . The obtained data suggests that in the absense of functionally active factor rho all the proteins necessary for phage DNA replication are formed . Besides, this factor is directly involved in the process of T-even phages DNA replication . One may conclude that the inability of T-even phages to develop in mutant cells rho is to a greater extent due to the impairment in phage DNA replication than to its transcription . The possible role of the factor rho in the process of DNA replication is discussed.

Mol Biol (Mosk), 1980 May-Jun, 14(3), 507 - 16
{Affinity labeling of ribosomes from Escherichia coli with 4-(N-2-chloroethyl, N-methylamino)-benzaldehyde actyl derivatives of oligouridylates}; Budker VG et al.; 4-(N-2-chloroethyl-N-methylamino)-benzaldehyde acetyl derivatives of penta-., hexa, hepta-, octauridylates were used for localization of the structures organizing the mRNA-binding centre of ribosomes . These derivatives, alike free oligonucleotides, stimulate the binding of phenylalanyl-tRNA to ribosomes . Within the specific complex all the oligonucleotide derivatives alkylated the 30S ribosomal subunit . Octauridylate and hexauridylate derivatives specifically alkylated also the 50S subunit of ribosomes . Polyuridylic acid protected ribosomal subunits from alkylation . In the 30S subunit the derivatives modify 16S RNA and proteins: S4, S5, S7, S9, S13, S15, S18, S21 . It was found that oligouridylate derivatives of different length alkylate different proteins.

Mikrobiologiia, 1980 May-Jun, 49(3), 440 - 4
{tRNA methyltransferase activity in Escherichia coli growing on a medium with methionine and S-methylmethionine}; Lebenka AIu et al.; tRNA methylating enzymes isolated from E . coli 113-3 grown in a medium with methionine or S-methylmethionine differed in the activity of transfer of the 14CH3-group from 14CH3-S-adenosyl-L-methionine (SAM) to tRNA in the in vitro experiments in heterological systems consisting of tRNA methyltransferases from E . coli 113-3 and a substrate of methylation, viz . methyl-deficient tRNA isolated from E . coli K 12W6 . In such a system, tRNA methyltransferases from E . coli 113-3 grown on S-methylmethionine methylated tRNA from E . coli K 12W6 at a rate almost twice as high as that in the case of the culture grown on methionine . At the same time, the activity of guanine methylation yielding 7-methylguanine increased significantly . The protein obtained after precipitation of cell-free extracts with ammonium sulfate was separated into four fractions using a system of columns packed with Sephadex G-25 and DEAE-cellulose . These fractions differed quantitatively in culture grown either on methionine or S-methylmethionine.

Infect Immun, 1980 May, 28(2), 387 - 92
Analysis of outer membrane components of Escherichia coli ML308 225 and of a serum-resistant mutant; Tee GL et al.; Escherichia coli ML308 225 in the early exponential phase of batch cultures was killed by human serum in a complement-dependent reaction . Under the same conditions, a mutant derived from this strain by multiple subcultures in human serum was resistant to killing by serum . The components of the outer membrane of both the parent and mutant strains were analyzed . The protein and phospholipid analyses were identical, but the mutant strain produced twice as much lipopolysaccharide as the parent strain . These results suggest that the extent of bacterial surface coverage by lipopolysaccharide determines the degree of sensitivity to serum.

Eur J Biochem, 1980 May, 106(2), 667 - 74
Photo-induced affinity labeling of Escherichia coli ribosomes by chloramphenicol; Le Goffic F et al.; In order to obtain more information about the binding site for chloramphenicol (D-threo diastereoisomer) on the bacterial ribosome, photo-affinity labeling experiments of this receptor have been performed with {3H}chloramphenicol itself . Control experiments show that this drug can be split photochemically by ultraviolet irradiation, whereas the ribosome is not modified structurally or functionally by such a treatment . When photolysis of a mixture of chloramphenicol and ribosomes is performed under critical conditions, some proteins like L1, L11, S3 and S4 are radiolabeled . L11, S3 and S4 are radiolabeled specifically as demonstrated by photo-incorporation experiments with isotopically diluted {3H}chloramphenicol or by comparison of the results obtained here with reversible experiments performed by the isotopic dilution method . When the D-erythro diastereoisomer of chloramphenicol is photo-incorporated into the bacterial ribosome, proteins are radiolabeled only in a non-specific way . These results show that this material could be used as an efficient scavenger . When finally D-threo {3H}chloramphenicol is photo-incorporated in the presence of a large amount of the D-erythro diastereoisomer, the radiolabeling pattern obtained for the proteins is quite different from that expected: while L11 is still labeled fairly extensively, L27 is the most radiolabeled protein found.

Eur J Biochem, 1980 May, 106(2), 495 - 503
A cross-linking study of the Ca2+, Mg2+-activated adenosine triphosphatase of Escherichia coli; Bragg PD et al.; The solubilized Ca2+,Mg2+-activated adenosine triphosphatase of Escherichia coli is composed of five subunits designated alpha, beta, gamma, delta and epsilon in order of decreasing molecular weight . The subunit structure of the enzyme has been investigated by the use of the cleavable cross-linking agents dithiobis(succinimidyl propionate), methyl-4-mercaptobutyrimidate, dimethyl-3,3'-dithiobispropionimidate, disuccinimidyl tartarate, and cupric 1,10-phenanthrolinate . The products of cross-linking were analyzed by two different two-dimensional gel electrophoresis systems . The following cross-linked subunit dimers were observed: alpha 2, beta 2, alpha beta, alpha delta, beta gamma, beta delta, beta epsilon and gamma epsilon . These results, together with other published data, are discussed in relation to a model of the arrangement of the subunits in the ATPase molecule.

Eur J Biochem, 1980 May, 106(2), 449 - 56
Quantitative study of the interaction of formylmethionyl-tRNAfMet with ribosomes of Escherichia coli; Ivanov YV et al.; fMet-tRNAfMet binds reversibly to the donor site (P-site) of Escherichia coli ribosomes both in the absence of messenger and in the presence of ApUpGp and some other oligonucleotides or poly(U) . Kinetics of interaction conforms the second-order law . The equilibrium constants and the rate constants of binding are estimated at 0 degrees C . Not only the cognate trinucleotide ApUpGp but also some other oligonucleotides and even poly(U) stimulate the binding . The presence of total deacylated tRNA considerably increases the selectivity of association.

Eur J Biochem, 1980 May, 106(2), 361 - 9
Protein mobility inside pyruvate dehydrogenase complexes as reflected by laser-pulse fluorometry . A new approach to multi-enzyme catalysis; Grande HJ et al.; The fluorescence decay curves of the flavin in all pyruvate dehydrogenase complexes studied here are consistent with a two-exponential fit . One of the lifetimes calculated is very short, as demonstrated by experiments in which a mode-locked argon-ion laser was used for excitation . In three complexes out of the four which were investigated, about equal weights for the amplitudes of the two lifetimes are found . In the three-component complex from Azotobacter vinelandii this is not the case . No effects of the protein concentration on the lifetimes of the fluorophore were found in the concentration range studied . A small but significant difference in lifetime is observed for the A . vinelandii complexes when coenzyme-free complex is compared with complex to which Mg2+ and thiamin diphosphate are added . The correlation time calculated from the polarized decay of the flavin fluorescence at 11 degrees C is around 40 ns and 50 ns for A . vinelandii complexes and Escherichia coli complexes respectively . This correlation time is of the same order as the rotational correlation time of free lipo-amide dehydrogenase itself, but much shorter than would be expected from the molecular weights of the complexes . Models explaining the two lifetimes are discussed . A catalytic mechanism based on the internal mobility of the lipoamide dehydrogenase inside the multi-enzyme complex is proposed.

Biofizika, 1980 May-Jun, 25(3), 469 - 72
{Proton-potassium exchange in Escherichia coli}; Durgar'ian SS et al.; Energy-dependent proton--potassium exchange in E . coli is suppressed by both ionophores and the inhibitor of hydrogen pumps N,N'-dichlohexilcarbodimide (DCCD) . The ratio of DCCD-sensitive fluxes of H+ and K+ is equal to 2:1 and does not depend upon the values of ionic fluxes, external pH, osmolarity and temperature . Bacteria can absorb synthetic cation tetraphenilphosphonium (TPP+) both in the absence of glucose and at addition of this source of energy . In the presence of glucose TPP+-ions are taken up by cells during the first 5-10 min and then they leave cells . Such glucose--dependent kinetics of TPP+ accumulation coincides with that for the first rapid phase of K+ uptake, but the process is observed, only if the glucose--independent absorption of TPP+ is small . The amount of accumulated TPP+ may be ascribed to the membrane potential of E . coli equalling--180mV . It is therefore considered that electrogenic proton-potassium pump sensitive to external osmolarity operates in E . coli cell membrane and exchanges 2H+ of the cell for 1K+ of external medium.

Bol Med Hosp Infant Mex, 1980 May-Jun, 37(3), 425 - 8
{Neonatal aortic thrombosis}; Gutierrez Carreno R et al.; A case of aortic thrombosis is reported in a 14 days old newborn after extensive review of the world literature is made . It was secondary to sepsis and hypercoagulability syndrome . Emphasis is placed on the early diagnosis, on the usefulness of the Doppler system when studying the vascular system as a non-invasive method in critically ill pediatric patients; likewise, on the determinant surgical procedure during the initial stages of the establishment of the aortic thrombosis.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2606 - 10
Homologous pairing in genetic recombination: formation of D loops by combined action of recA protein and a helix-destabilizing protein; Shibata T et al.; Escherichia coli single-strand binding protein (SSB) or phage T4 gene 32 protein reduced the amount of recA protein required to catalyze the formation of D loops from double-stranded DNA and homologous single-stranded fragments . Neither SSB nor gene 32 protein alone catalyzed the formation of D loops, and excessive amounts of either protein, amounts that were sufficient to saturate the single strands, inhibited the formation of D loops completely . Both the stimulatory activity and the inhibitory activity of SSB resisted boiling, which is consistent with the known thermal stability of SSB, whereas the gene 32 protein was inactivated by heating . The formation of D loops in the presence of both recA protein and SSB required homologous DNA and ATP . Spermidine aided the combined action of SSB and recA protein in forming D loops, but Mg2+ alone was sufficient as a counterion.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2592 - 5
Autogenous control of Escherichia coli ribosomal protein L10 synthesis in vitro; Brot N et al.; The DNA-dependent in vitro synthesis of Escherichia coli ribosomal protein L10 was inhibited when L10 was added to the protein-synthesizing incubations . Addition of L10 had little or no effect on the synthesis of ribosomal protein L12, elongation factor Tu (tufB), or the beta and beta' subunits of RNA polymerase . In addition, ribosomal protein L12 did not inhibit its own synthesis or the synthesis of L10 . Experiments using a mRNA-directed system showed that the inhibition of the synthesis of L10 by itself is at the level of translation of protein synthesis . The mechanism of inhibition does not appear to be due to increased degradation of L10 mRNA.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2434 - 8
Structural studies of methyl-accepting chemotaxis proteins of Escherichia coli: evidence for multiple methylation sites; Chelsky D et al.; Two-dimensional analysis of tryptic peptides from {35S}methionine-labeled methyl-accepting chemotaxis proteins, MCP I and MCP II, demonstrates a high degree of homology between the two proteins . After the methylation sites were labeled with S-adenosyl-L-methyl-3H}methionine, peptides of three distinct migrations in each protein were found to carry a methyl group . These multiple methylations appear to be responsible in part for the observed multiple banding patterns on sodium dodecyl sulfate/polyacrylamide slab gels.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2390 - 4
DNA synaptase: an enzyme that fuses DNA molecules at a region of homology; Potter H et al.; This paper describes an enzyme from Escherichia coli, and its purification to apparent homogeneity . The protein, which we call "DNA synaptase" and which may be representative of a class of enzymes, fuses double-stranded DNA molecules at a region of homology . In addition, the purified enzyme is able to catalyze the association of single-stranded DNA with homologous duplex DNA . The genome fusion reaction catalyzed by the purified enzyme occurs in the presence of Mg2+, spermidine, and 2-mercaptoethanol and does not require a high-energy cofactor . By bringing two genomes together at a region of homology, DNA synaptase has a property expected for an enzyme that participates in an early step in genetic recombination . However, the synaptase can be recovered from Rec A- cells, and thus it is not yet possible to determine whether this enzyme plays a role in physiological recombination or in another cellular process that involves genome fusion, such as the recombinational repair of damaged DNA.

Chem Biol Interact, 1980 May, 30(2), 203 - 7
Comparative mutagenicity of linear and angular furocoumarins in Escherichia coli strains deficient in known repair functions; Venturini S et al.; Four furocoumarins, two having a linear molecule, psoralen and 8-methyl-psoralen and two having an angular molecule, angelicin and 4,5'-dimethyl-angelicin were tested for mutagenesis in Escherichia coli B wild type and in various strains deficient in known repair systems . The results indicate that both monoadducts and crosslinks are mutagenic . The mutagenic efficiency of the furocourmarins ranks in the following order 8-methylpsoralen psoralen greater than angelicin greater than 4,5'-dimethylangelicin.

J Med Microbiol, 1980 May, 13(2), 265 - 71
Passive protection of lambs against enteropathogenic Escherichia coli: role of antibodies in serum and colostrum of dams vaccinated with K99 antigen; Morris JA et al.; Lambs from suckling ewes vaccinated with the K99 antigen were resistant to challenge with K99-positive enteropathogenic Escherichia coli . Serum and colostrum from these ewes were compared with samples from control ewes to establish methods for monitoring vaccination and to determine the mechanism of protection . Vaccination stimulated production of K99 antibodies . These could be detected by an indirect haemagglutination test and a haemagglutination-inhibition test . Antiglobulin and gel-diffusion tests were less reliable . Experiments with brush-border cells from calf intestine showed that the antibodies were associated with anti-adhesive activity . The antibodies were predominantly IgG and did not neutralise the activity of heat-stable enterotoxin . It was concluded that neutralisation of the adhesive properties of the K99-positive E . coli by colostral antibodies significantly contributed to the resistance of the lambs from vaccinated ewes.

J Bacteriol, 1980 May, 142(2), 615 - 20
Organization of genes in the ftsA-envA region of the Escherichia coli genetic map and identification of a new fts locus (ftsZ); Lutkenhaus JF et al.; Complementation tests have revealed that the mutation in the filamenting mutant PAT84 is distinct from ftsA and has been designated ftsZ . By isolating transducing phages carrying various amounts of the bacterial deoxyribonucleic acid in this region, it was possible to locate the ftsZ gene between ftsA and envA . It is concluded that these cell division genes are expressed independently of the neighboring murein genes.

J Bacteriol, 1980 May, 142(2), 535 - 46
Effect of the uvrD mutation on excision repair; Kuemmerle NB et al.; A pair of related Escherichia coli K-12 strains, one of which contains the uvrD101 mutation, were constructed and compared for ability to perform various steps in the excision repair of deoxyribonucleic acid damage inflicted by ultraviolet radiation . The results of this study indicated: (i) ultraviolet sensitivity in the uvrD101 mutant was greater than that of wild type but less than that measured in an incision-deficient uvrA mutant; (ii) host cell reactivation paralleled the survival data; (iii) postirradiation deoxyribonucleic acid degradation was virtually identical in the two strains; (iv) incision, presumably at the sites of pyrimidine dimers, proceeded normally in the uvrD101 strain; (v) excision of pyrimidine dimers was markedly reduced in both rate and extent in the uvrD101 mutant; (vi) the amount of repair resynthesis was the same in both strains, and there was no evidence of abnormally long repair patches in the uvrD mutant; and (vii) rejoining of incision breaks was slow and incomplete in the uvrD strain . These data suggest that the ultraviolet sensitivity conferred by the uvrD mutation arises from inefficient removal of pyrimidine dimers or from failure to close incision breaks . The data are compatible with the notion that the uvrD+ gene produce affects the conformation of incised deoxyribonucleic acid molecules.

J Bacteriol, 1980 May, 142(2), 527 - 34
Tumbling chemotaxis mutants of Escherichia coli: possible gene-dependent effect of methionine starvation; Kondoh H; Some mutants defective in chemotaxis show incessant tumbling behavior and are called tumbling mutants . Previously described tumbling mutations lie in two genes, cheB and cheZ (41.5 min on Escherichia coli map) . Genetic analysis of various tumbling mutants, however, revealed that two more genetic loci, cheC (43 min) and cheE (99.2 min), could also mutate to produce tumbling mutants . The genetic map around cheC was revised: his flaP flaQ flaR flbD flaA (= cheC) flaE . flbD is a new gene . When cells were starved for methionine, the tumbling mutants changed their swimming behavior depending on the che gene mutated . cheZ mutants, like wild-type bacteria, ceased tumbling shortly after removal of methionine . The tumbling of cheB or cheE mutants was depressed after prolonged methionine starvation in the presence of a constant level of an attractant . cheC tumbling mutants appeared unique in that they did not cease tumbling even when cells were deprived of methionine . By contrast, arsenate treatment of the tumbling mutants resulted in smooth swimming of the cells in every case . These results suggest that two different processes are involved in regulation of tumbling; one requiring methionine and the other requiring some phosphorylated compound.

J Bacteriol, 1980 May, 142(2), 462 - 6
Integrative compatibility: stable coexistence of chromosomally integrated and autonomous derivatives of plasmid RP4; Watson MD et al.; P group plasmid RP4 lambda att has a novel feature . Its incompatibility function is phenotypically switched off when it integrates into the bacterial chromosome.

Gastroenterology, 1980 May, 78(5 Pt 1), 1001 - 4
Endotoxemia of cirrhosis: an observation not substantiated; Fulenwider JT et al.; Physiologic similarities between cirrhotic and septic patients have implicated systemic endotoxemia as a possible mediator of the hemodynamic, neurologic, and hematologic complications observed in patients with cirrhosis of the liver . The recently reported high prevalence of endotoxin in ascites, as well as in portal and systemic plasma, has further incriminated endotoxin of gut origin as the responsible agent . Limulus amebocyte lysate tests were performed upon peripheral plasma of 38 cirrhotic patients; portal plasma and ascites were assayed in 14 and 11 of these patients, respectively . No endotoxin was detectable . We believe that the ubiquity of endotoxin, with the attendant opportunities for specimen contamination, is the most likely explanation for the recently reported high prevalence of endotoxin in the plasma and ascites of cirrhotic patients.

J Virol, 1980 May, 34(2), 438 - 45
Rescue of abortive T7 gene 2 mutant phage infection by rifampin; Ontell MP et al.; Infection of Escherichia coli with T7 gene 2 mutant phage was abortive; concatemeric phage DNA was synthesized but was not packaged into the phage head, resulting in an accumulation of DNA species shorter in size than the phage genome, concomitant with an accumulation of phage head-related structures . Appearance of concatemeric T7 DNA in gene 2 mutant phage infection during onset of T7 DNA replication indicates that the product of gene 2 was required for proper processing or packaging of concatemer DNA rather than for the synthesis of T7 progeny DNA or concatemer formation . This abortive infection by gene 2 mutant phage could be rescued by rifampin . If rifampin was added at the onset of T7 DNA replication, concatemeric DNA molecules were properly packaged into phage heads, as evidenced by the production of infectious progeny phage . Since the gene 2 product acts as a specific inhibitor of E . coli RNA polymerase by preventing the enzyme from binding T7 DNA, uninhibited E . coli RNA polymerase in gene 2 mutant phage-infected cells interacts with concatemeric T7 DNA and perturbs proper DNA processing unless another inhibitor of the enzyme (rifampin) was added . Therefore, the involvement of gene 2 protein in T7 DNA processing may be due to its single function as the specific inhibitor of the host E . coli RNA polymerase.

Ann Surg, 1980 May, 191(5), 626 - 35
Cholecystitis, cholelithiasis and common duct stenosis in children and adolescents; Holcomb GW Jr et al.; A study of 100 patients from 14 months through 18 years of age with extrahepatic biliary tract conditions who have been treated from 1950 through 1979 is reported . For discussion, these have been classified into four groups including acalculous cholecystitis, nonhemolytic cholelithiasis, hemolytic cholelithiasis and stenosis of the common duct . Ninety-nine patients were operated on and there were no deaths . Except for unusual contraindications, cholecystectomy is preferred for acute noncalculous cholecystitis . The largest number having gallstones were those patients (87%) without hemolytic disease . Only 13% had an associated hemolytic disorder . Cholecystectomy is the preferred treatment and common duct exploration is utilized when indicated . Six children with chronic relapsing pancreatitis secondary to stenosis of the ampulla of Vater and two with common duct stenosis are analyzed . Although extrahepatic biliary disorders are usually not considered in the differential diagnosis of children and adolescents with vague abdominal pain, it is evident by this large number of patients that there should be greater emphasis placed on earlier diagnosis in the future.

Am J Obstet Gynecol, 1980 May 1, 137(1), 53 - 7
The role of prostaglandins in endotoxemia: comparisons in response in the nonpregnant, maternal, and fetal models . I . Prostaglandins and the pulmonary effect of experimental endotoxemia; Cefalo RC et al.; The mechanism of respiratory distress in sepsis is unknown . Previous work has shown elevations of prostaglandins during sepsis . This study reveals a correlation between levels of prostaglandins F 2 alpha and E and pulmonary hypertension and other parameters of respiratory distress in oophorectomized ewes subjected to endotoxin . The use of prostaglandin synthetase inhibitors prior to endotoxin prevented the rise in prostaglandins and the development of respiratory distress.

Surgery, 1980 May, 87(5), 588 - 92
Mechanisms of the adjuvant effect of hemoglobin in experimental peritonitis . III . The influence of hemoglobin on phagocytosis and intracellular killing by human granulocytes; Hau T et al.; The effect of hemoglobin on the ability of polymorphonuclear granulocytes (PMNs) to phagocytize and kill opsonized E . coli was measured . Results show that the addition of hemoglobin in a concentration of 0.1% inhibititis phagocytotic activity of PMNs from 68% to 13% after 30 minutes and from 73% to 45% after 60 minutes . The rate of intracellular killing after the addition of hemoglobin in the concentration of 0.5% declined from 63% to 21% . Though these experiments do not allow any conclusions as to the exact mechanism of action of hemoglobin in inhibition of phagocytosis, it seems likely from other data that the inhibitory activity resides in the heme part of the molecule . We conclude that hemoglobin inhibits phagocytotic activity and the ability to kill ingested bacteria of human polymorphonuclear granulocytes . This provides an additional mechanism for the adjuvant action of hemoglobin in intraperitoneal infections and supports the theory that hemoglobin acts directly on the granulocyte to impair the essential host defenses.

J Trauma, 1980 May, 20(5), 410 - 2
Protective effect of a splenic extract in mice with endotoxemia; Spillert CR et al.; We have previously described the isolation of a lipoidal splenic extract (LSE) that demonstrated a variety of hematologic effects including inhibition of platelet aggregation both in vivo and in vitro . Since endotoxin causes platelet aggregation and microembolism the protective effect of LSE in endotoxemia was examined in the present study . Both young and elderly Swiss mice given LSE 2--3 hours before endotoxin challenge showed a statistically significant increase in survival compared with saline-treated controls . However, no significant improvement in survival was noted when LSE was administered at the same time as endotoxin . These results add further support to the role of the spleen in the control of infection.

J Immunol, 1980 May, 124(5), 2117 - 21
Mitogen-induced plasma cell differentiation in patients with multiple sclerosis; Levitt D et al.; Cellular interactions involved in mitogen-stimulated plasma cell differentiation were investigated in eight patients with severe but stable multiple sclerosis (MS) . No significant differences were detected between normals and MS patients with regard to percent of B lymphocytes and T lymphocytes in peripheral blood . Autologous and allogeneic combinations of normal and MS B and T cells were stimulated with pokeweed mitogen (PWM) and E . coli lipopolysaccharide (LPS), and plasma cell differentiation was monitored after 7 days in culture . T lymphocytes from patients with MS induced 2- to 4-fold increases in plasma cell development when combined with normal B cell fractions . Allogeneic combinations on normal B and T cells did not provide enhanced plasma cell generation . B lymphocytes from MS patients exhibited poor responses to both PWM and LPS when cultured with their own or normal T cells . Such B cell fractions did not differ from normals with regard to percent monocytes or surface Ig+ B lymphocytes initially contained in these cell populations . We conclude that T cells from MS patients are able to provide excessive help for normal B cell differentiation due either to increased T helper activity or deficient T suppressor activity . B cell differentiation may be diminished in MS patients as a result of a deficiency of a population of B cells in blood that are able to be stimulated by polyclonal B cell activators.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2611 - 5
Sequences of the recA gene and protein; Sancar A et al.; We have determined the nucleotide sequence of the recA gene of Escherichia coli; this permits the formulation of the primary structure for the recA protein . This structure is consistent with the amino acid composition of the tryptic peptides obtained from the recA protein . The coding region of the recA gene has 1059 base pairs, which specify 352 amino acids . The recA protein has alanine and phenylalanine as its NH2- and COOH-terminal amino acids, respectively, and has the following amino acid composition: Cys3 Asp20 Asn15 Met9 Thr17 Ser20 Glu30 Gln13 Pro10 Gly35 Ala38 Val22 Ile27 Leu31 Tyr7 Phe10 His2Lys27 Trp2 Arg14 . Of the three cysteine residues, only two can be alkylated under reducing and denaturing conditions . The molecular weight of the recA polypeptide is 37,842.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2445 - 9
Sequences of two kinetoplast DNA minicircles of Tryptanosoma brucei; Chen KK et al.; Kinetoplast DNA of Trypanosoma brucei is composed of a network of about 10,000 interlocked minicircle DNA molecules (1.0 kilobase) that are catenated with about 50 maxicircle DNA molecules (23 kilobases) . Several different DNA . DNA hybridization techniques using individual minicircle DNA sequences cloned in Escherichia coli have indicated that each minicircle molecule contains about one-fourth of its sequence in common with most other minicircles and the remaining three-fourths in common with about 1 out of every 300 minicircles . We have determined the complete sequence of two cloned minicircle DNA molecules that were released from the total kinetoplast DNA network by different restriction enzymes; one minicircle is 1004 base pairs long, the other is 983 base pairs . Both are about 72% dA + dT . They share about 27% of their sequences; the largest continuous region in common is 122 base pairs of near-perfect homology . Twelve other regions of perfect homology equal to or greater than 10 base pairs are also present . Both sequences contain a large number of translation termination codons in all potential translation reading frames . The largest oligopeptide potentially specified by one minicircle sequence is 52 amino acids; the largest by the other minicircle sequence is 71 amino acids . One minicircle contains a decanucleotide sequence that is repeated in tandem five times . It is proposed that massive recombination among the interlocked minicircles in the kinetoplast DNA network may account for much of the homology observed in the two minicirce sequences.

Eur J Biochem, 1980 May, 106(1), 313 - 20
Identification of a class of lysines within the non-specific DNA-binding site of RNA polymerase core enzyme from Escherichia coli; Makoff AJ et al.; The imido ester, methyl acetimidate, which specifically amidinates lysine residues, modifies RNA polymerase core enzyme, leading to rapid loss of activity . Calf thymus DNA partially protects the enzyme against this inactivation, an effect which disappears at high salt concentration . DNA protects 17 +/- 6 lysines from amidination at low salt concentration . The dependence of amidination on methyl acetimidate concentration is examined in the presence of DNA at high and low salt concentration . Analysis of the data suggests a class of approximately 12 lysines which are protected by DNA, consistent with the above estimate . These lysines are approximately 5--10-fold more reactive than most other available lysine residues.

Ann Immunol (Paris), 1980 May-Jun, 131C(3), 397 - 404
Immunosuppression associated with erythropoiesis in genetic low responder mice; Conway de Macario E et al.; Priming-memory generation in response to Escherichia coli beta-D-galactosidase occurs without antibody formation in irradiated spleen-cell-transferred C57BL/6J mice, which are genetic low responders to the enzyme . Erythropoiesis abolishes priming-memory generation, so that recipients immunized a few days after cell transfer and erythropoiesis induction do not mount a secondary antibody response . Priming-memory generation in cell recipients immunized 3 days after erythropoiesis induction was less frequent than in controls, whereas no significant differences were found when antigen was given before erythropoiesis induction or 5 days after it . The mean titre of the mice escapint suppression was similar to that of the control mice, which became primed and mounted memory . The titre distribution in both responder groups were also similar, although no high-titered responders were found in the erythropoietic mice . Thus while erythropoiesis induction affects the frequency of priming-memory generation, it does not affect to the same extent the amount of memory generated in those mice escaping suppression . The same distinction was observed when spleen cells from erythropoietic mice, containing 30 to 40% erythroblasts, were transferred into normal mice . However, induction of erythropoiesis in non-irradiated non-cell=transferred mice did not cause suppression.

Z Naturforsch {C}, 1980 May-Jun, 35(5-6), 522 - 5
On the reactivity of pyridoxal-5'-phosphate with yeast tRNAPhe and tRNATyr; Okabe N et al.; Yeast tRNAPhe and tRNATyr were reacted with the fluorescent reagent pyridoxal-5'-phosphate and the modified tRNAs were analysed with respect to the number and position of modified nucleosides and with respect to aminoacylation . a) Following the intrinsic fluorescence of pyridoxal-5'-phosphate, the treatment of tRNATyr with increasing amounts of pyridoxal-5'-phosphate revealed about 50 mol or reagent or a even higher number bound per one mol of tRNATyr . After borohydride reduction (in order to stabilize the linkage) of this modified tRNATyr and purification with reverse phase chromatography a modified tRNATyr was obtained carrying about 2 mol of the reagent . b) Both tRNATyr and tRNAPhe treated with pyridoxal-5'-phosphate and reduced exhibited almost unchanged aminoacylation as compared to the unmodified tRNAs . c) Pyridoxal-5'-phosphate treated and reduced tRNAPhe and tRNATyr were digested with ribonuclease T1 and the resulting oligonucleotides were separated . However, no fluorescent oligonucleotide and no difference to an oligonucleotide pattern obtained from unmodified tRNA were observed . Thus, pyridoxal-5'-phosphate might have been bound to the highly purified yeast tRNAPhe and tRNATyr samples either via an unstable linkage or not covalently . This result is controversial with respect to the specific reaction of pyridoxal-5'-phosphate with unfractionated tRNAs from colon carcinoma and tRNAs from E . coli as reported in the literature.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2819 - 23
DNA-damaging agents stimulate gene expression at specific loci in Escherichia coli; Kenyon CJ et al.; Operon fusions in Escherichia coli were obtained that showed increased beta-galactosidase expression in response to treatment with the DNA-damaging agent mitomycin C . These fusions were generated by using the Mud(ApR, lac) vector {Casadaban, M.J . & Cohen, S.N . (1979) Proc . Natl . Acad . Sci . USA 76, 4530-4533} to insert the lactose structural genes randomly into the bacterial chromosome . Induction of beta-galactosidase in these strains, which carried fusions of lac to these din (damage-inducible) loci, was (i) triggered by UV light as well as by mitomycin C and (ii) abolished by either a recA- or a lexA- mutation . Similar characteristics of induction were observed when the lactose genes were fused to a prophage lambda promoter by using Mud(ApR, lac) . These results indicate that E . coli contains a set of genes that, like prophage lambda genes, are expressed in response to DNA-damaging agents and regulated by the recA and lexA gene products . These din genes map at five bacterial loci . One din::Mud(ApR, lac) insertion results in a UV-sensitive phenotype and may be within the uvrA transcriptional unit.

J Bacteriol, 1980 May, 142(2), 732 - 4
Positions of early nonsense and deletion mutations in lacZ; Welply JK et al.; The positions of three Escherichia coli lacZ operator-proximal nonsense mutations and one deletion mutation have been determined . The nonsense mutations were suppressed with supF, resulting in the production of active beta-galactosidase by each strain . Amino acid sequencing identified the positions of the tyrosine residues inserted by supF, and thereby established that nonsense mutations lacZ2, lacZ2246, and lacZU131 are at sites corresponding to amino acids 23, 36, and 41 of beta-galactosidase, respectively . The deletion mutant, lacZM112, produced a dimeric beta-galactosidase protein missing amino acid residues 23 through 31 of the native enzyme.

J Nucl Med, 1980 May, 21(5), 480 - 3
Modifications in biphasic liquid-scintillation vial system for radiometry; Ganatra RD et al.; Several modifications of the biphasic liquid-scintillation vial system for radiometry have been tried in order to improve the counting efficiency . The biphasic system consisted of an inner sterile vial containing medium and substrate, and an outer liquid-scintillation vial lined on the inside with filter paper impregnated with scintillation fluors and alkali . The system gave an overall counting efficiency of 14.6% . Substitution of methanolic NaOH for impregnation of the paper raised the counting efficiency to 29.1% . This could be further enhanced to 33.8% by lining only half of the outer vial with filter paper, thereby allowing improved optical transmission of scintillation light . Increasing the amount of fluor did not change the efficiency significantly . A complete interchange in the system, whereby half of the inner vial was lined with filter paper and was otherwise empty, while the outer vial contained the medium and substrate, gave the highest efficiency (36.9%) . This also allowed the use of larger amounts of medium and the inoculum.

Appl Environ Microbiol, 1980 May, 39(5), 1046 - 53
Temperate coliphages: classification and correlation with habitats; Dhillon EK et al.; Temperate coliphages were recovered from sewage, mammalian feces, and lysogenic strains of Escherichia coli . A total of 32 phages of independent origin were divided into six groups by applying the criteria of host range, antigenic homology, and the ultraviolet inducibility of the prophage . The demonstration of genetic interactions in some cases has confirmed the classification scheme . Nine phages were assigned to the P2 family and 19 to the lambda family . The remaining four isolates may represent some novel phylogenetic types . Phages recovered from the lysogenic strains of E . coli were all found to be P2 related, whereas a majority of the phages recovered as cell-free plaque-forming units were assignable to the lambda family . It is proposed that the biological attributes of the phages belonging to the two principal families are reflected in the distribution patterns observed . The virions of phage HK256 show multiple tail fibers and may thus represent a "new" virion form among the temperate coliphages.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2621 - 5
DNA sequence encoding the NH2-terminal peptide involved in transport of lambda receptor, an Escherichia coli secretory protein; Hedgpeth J et al.; lamB encodes the lambda receptor of Escherichia coli, an outer membrane protein . We have identified the beginning of the lamB gene by correlating DNA nucleotide sequence with a partial sequence of the primary translation product of lamB . We show that lambda receptor is synthesized as a precursor containing an extra 25 amino acids at its NH2 terminus . These amino acids are predominately hydrophobic and probably comprise a structure required for initiation of transport of lambda receptor from the cytoplasm to the outer membrane.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2569 - 73
Recognition of duplex DNA containing single-stranded regions by recA protein; West SC et al.; Genetic recombination in Escherichia coli requires recA protein, the product of the recA+ gene . In this paper we show that purified recA protein, which binds strongly to denatured DNA, cooperatively recognizes DNA containing short single-stranded regions . The interaction of varying amounts of recA protein with DNA molecules was investigated by measuring its DNA-dependent ATPase activity . In 3mM Mg2+, the ATPase activity was stimulated by excess single-stranded DNA and was minimal with either intact circular or blunt-ended linear duplexes . Single-strand gaps of about 30 nucleotides were sufficient to increase the ATPase activity to a level almost as great as that observed with single-stranded DNA . Sedimentation studies at neutral pH showed cooperative binding of recA protein to single-stranded DNA or to duplex DNA containing single-stranded regions . In the presence of ATP, an intermediate rate of sedimentation was observed; in contrast, adenosine 5'-gamma-thiotriphosphate (ATP{S}) caused the formation of fast-sedimenting DNA-protein complexes . Gapped plasmid DNA plus recA protein and ATP{S} formed large aggregates containing thousands of molecules . Complex formation and stimulation of the ATPase activity of recA protein with duplex DNA containing single-stranded regions indicates that recA protein may change the conformation of the normally duplex molecules to a conformation prepared for homologous pairing.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2519 - 23
Stimulatory effect of low ATP pools on transport of purine nucleosides in cells of Escherichia coli; Munch-Petersen A et al.; Cells of Escherichia coli contain two nucleoside-transport systems . Energy-starved cells of a strain containing only one of these systems and, in addition, carrying a mutation in the Ca2+- and Mg2+-dependent ATPase (ATP phosphohydrolase 3.6.1.3) are still able to transport nucleosides . The rate is only slightly lower than the rate measured in unstarved cells . Freshly harvested uncA cells transport purine nucleosides at a higher rate than cells from the isogenic strain containing a functional ATPase . If cells from the latter strain are treated with arsenate, transport rates increase to the same levels as found in uncA cells . The presence of an uncA mutation has no effect on the transport rates for cytidine, deoxycytidine, and uridine, nor has arsenate treatment . These findings indicate that ATP is not required as energy donor for nucleoside transport . The enhanced transport rate for purine nucleosides after treatment with arsenate seems to suggest a regulatory relationship between the transport of these nucleosides and the cellular levels of ATP or a closely related metabolite.

Eur J Biochem, 1980 May, 106(1), 179 - 92
Nucleotide sequence of the simian virus 40 HindII + III restriction fragment I (fourth part of the T antigen gene); Van Herreweghe J et al.; The HindII + III restriction fragment I (Hind-I) from simian virus 40 DNA represents 4.96% of the genome and maps in the early transcription region . Hind-I is an internal segment of the A gene and its information is expressed as part of the early 19-S mRNA, which codes for T antigen . We report here the nucleotide sequence of the 259-base-pair Hind-I fragment . The sequence was determined and confirmed by RNA and DNA sequencing methods: by analysis of oligonucleotides resulting from T1 and pancreatic RNase digestion of labeled RNA transcribed from SV40 DNA with Escherichia coli DNA-dependent RNA polymerase, by partial degradation of RNA transcripts with snake venom phosphodiesterase, and by base-specific chemical degradation of 5'-end-labeled subfragments of Hind-I according to the procedure of Maxam and Gilbert . Multiple triplets corresponding to termination codons occur in two of the three reading frames of the DNA strand that has the same polarity as early mRNA . The open reading frame connects in phase with the one of the Hind fragments flanking Hind-I, and the amino acid sequence specified by Hind-I lies in the middle part of the large-T antigen . Some features of the primary nucleotide sequence and of early transcription are discussed.

Arch Dis Child, 1980 May, 55(5), 376 - 9
Oral rehydration therapy for treatment of rotavirus diarrhoea in a rural treatment centre in Bangladesh; Taylor PR et al.; PIP: The outcome of a rehydration treatment used during a 40-day period at a WHO Center in Bangladesh on 216 children under age 5 is reported . In addition, an enzyme-linked immunosorbentassay (ELISA) designed to detect rotavirus in stool specimens is described and its application explained . The ELISA assay was adaptable to use in a rural treatment center . In a 40-day period, using the new virus-detecting assay, rotavirus without other pathogens was found in stools of 216 (45%) of 480 children who attended the center with gastrointestinal illness . Of these 216 children with only rotavirus pathogen, 188 were treated with oral rehydration alone (oral glucose solution prepared according to WHO procedures); 28 required additional intravenous rehydration therapy . No deaths occurred . 95% of the cases were judged successful on oral rehydration alone for gastrointestinal effects of rotavirus infection . No serious side effects were reported . This oral glucose solution is now indcated in E . coli (enter otoxin)-mediated diarrhea as well as in rotavirus-induced diarrhea .

Ann Microbiol (Paris), 1980 May-Jun, 131(3), 233 - 47
The lactose transposon Tn951: characterization of transposition; Cornelis G et al.; Transposition of the lactose transposon Tn951 was found to still occur in the absence of its original host plasmid pGC1 . Transposition was recA-independent . These results show that Tn951 is indeed a transposon . A computer program was developed to facilitate mapping of transposon integration sites in plasmids from restriction data.

Mol Biol (Mosk), 1980 May-Jun, 14(3), 615 - 23
{Cloning of fragments of lambda phage DNA, containing red and gam genes}; Khodkova EM et al.; On the base of plasmid pCV20 (Apr, Tcr mol . weight 5.2 x 10(6) a recombinant plasmid pEH60 (Apr, mol . weight 17.0 x 10(6) with BamHI fragment of phage DNA, containing red+ and gam+ genes was constructed . Selection was found on the ability of phage red- and gam- to propagate in strain E . coli K12 recA-, which was transformed by recombinant plasmid with active red and gam genes . Influence of recombinant plasmid pEH60 on processes of repair and recombination of phage lambda DNA and bacterial DNA was studied . It was shown that red gene in plasmid pEH60 compensates deficiency of redA gene in these processes with phage lambda DNA; in the case of E . coli K12 AB2480 uvr- recA- (pEH60) the processes of multiple reactivation and decombination of phage red- were presented . In the case of bacterial cells, plasmid pEH60 did not compensate deficiency of recA function of bacteria, although it partly compensates deficiency of recBC function . Increase of survival after introduction of plasmid pEH60 in the cell was obtained only for recBC- strain, but not for wild type and recA- strains.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2814 - 8
Recombination genes on the Escherichia coli sex factor specific for transposable elements; Hopkins JD et al.; The Escherichia coli sex factor stimulates precise excision of transposons Tn5 and Tn10 from sites either within the bacterial chromosome or within the factor itself . We have isolated two kinds of mutations that affect this activity . The ferA mutations eliminate the stimulation; the ferB mutations enhance it in the presence of FerA+ . We conclude that ferA defines a sex factor gene that stimulates precise excision . The ferB mutations also specifically increase the rate of recombination between two IS3 elements on F' lac-pro (F'128) in a reaction that requires the product of recA . The stimulation of this recombination by ferB also requires an active ferA gene, which implies that the ferA gene stimulates this reaction as well as precise excision . A ferA mutation was mapped at 84.2 kilobases on the F factor, and a ferB mutation was mapped at 82.5 kilobases . The fer mutants were obtained by an approach that permits the isolation of mutants affecting precise excision.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2626 - 30
Acetate kinase: a triple-displacement enzyme; Spector LB; Facts relating to the mechanism of phosphoryl transfer by acetate kinase (ATP:acetate phosphotransferase, EC 2.7.2.1) are reviewed . They point to the existence of at least one experimentally established phosphoenzyme (E-P) intermediate on the reaction pathway . Sterically, the phosphoryl transfer occurs with a net inversion of the configuration of the phosphorus atom . These facts are best in accord with a triple-displacement mode of action for acetate kinase, with two E-P intermediates and three steric inversions on phosphorus . It follows that a second E-P for acetate kinase must exist.

Proc Natl Acad Sci U S A, 1980 May, 77(5), 2514 - 8
Fate of donor insertion sequence IS1 during transposition; Read HA et al.; The number of insertion sequence IS1 segments in Escherichia coli K-12 and 20 mutants in which an ISI had been inserted at a new site was measured by Southern blot hybridization analysis . The parent strain appeared to contain seven IS1 segments . Each of the mutants contained these seven IS1 and one additional IS1 corresponding to the new IS1 insertion . These results suggest that a copy of a donor ISI is inserted at the new site . A model for transposition is prevented that postulates that a reactive intermediate is formed by a tandem duplication of a transposable sequence.

J Biochem (Tokyo), 1980 May, 87(5), 1449 - 55
Comparative studies on alveolar macrophages and polymorphonuclear leukocytes . I . H2O2 and O2- generation by rabbit alveolar macrophages; Yamaguchi T et al.; The oxidative metabolism of rabbit alveolar macrophages (A-MO) was compared with that of rabbit polymorphonuclear leukocytes (PMN) with respect to H2O2 generation by intact cells or subcellular fractions . Rabbit PMN exhibited an increase in the oxygen uptake and a marked release of H2O2 upon addition of heat-killed E . coli in the presence and absence of opsonin . However, rabbit A-MO exhibited an increase in the oxygen uptake upon addition of E . coli only in the presence of anti-E . coli serum as an opsonin, whereas a very small amount of H2O2 release was observed during ingestion of the opsonized E . coli . The generation of O2- and H2O2 by a granule-rich fraction isolated from phagocytosing PMN was larger than that by a similar fraction isolated from resting PMN . However, there was no significant difference in O2- and H2O2 generation by the granule fractions between phagocytosing and resting A-MO in the presence of either NADH or NADPH . In contrast to the granule fraction of rabbit PMN, the O2- and H2O2 generating activities in the A-MO granule fraction were higher in the presence of NADH than in the presence of NADPH . The rates of NADH and NADPH oxidation by both A-MO and PMN granule fractions were measured with and without addition of Mn2+ to the assay medium . The effect of Mn2+ on the NAD(P)H oxidase was found to differ between rabbit A-MO and PMN.

Gene, 1980 May, 9(3-4), 307 - 19
Cloning DNA restriction endonuclease fragments with protruding single-stranded ends; Wartell RM et al.; A new method of in vitro recombination was employed to construct plasmids containing lac promoter fragments 64 bp and 144 bp long . The 64 bp HpaII-HhaI fragment contains the binding site for the catabolite activator protein (CAP) . The HpaII-HaeIII 144 bp fragment includes the binding sites for RNA polymerase, the lac repressor and CAP . The method utilizes the ability of T4 DNA polymerase to make flush-ended DNA either by filling in a recessed 3'-end or by exonucleolytic removal of a protruding 3'-end . The treated fragments were then blunt-end ligated to the filled-in EcoRI cloning sites of the plasmids pVH51 and pBR322 using T4 ligase . In this process, the EcoRI sites were regenerated on the fragment ends thus facilitating the subsequent isolation of the fragments from their cloning vectors.

Gene, 1980 May, 9(3-4), 287 - 305
Construction and characterization of new cloning vehicles . IV . Deletion derivatives of pBR322 and pBR325; Soberon X et al.; In vitro recombinant DNA experiments involving restriction endonuclease fragments derived from the plasmids pBR322 and pBR325 resulted in the construction of two new cloning vehicles . One of these plasmids, designated pBR327, was obtained after an EcoRII partial digestion of pBR322 . The plasmid pBR327 confers resistance to tetracycline and ampicillin, contains 3273 base pairs (bp) and therefore is 1089 bp smaller than pBR322 . The other newly constructed vector, which has been designated pBR328, confers resistance to chloramphenicol as well as the two former antibiotics . This plasmid contains unique HindIII, BamHI and SalI sites in the tetracycline resistance gene, unique PvuI and PstI sites in the ampicillin resistance gene and unique EcoRI, PvuII and BalI sites in the chloramphenicol resistance gene . The pBR328 plasmid contains approx . 4900 bp.

Gene, 1980 May, 9(3-4), 213 - 31
The recognition site of type II restriction enzyme BglI is interrupted; Lautenberger JA et al.; The Type II restriction endonuclease BglI recognizes the interrupted DNA sequence 5'-G-C-C-N-N-N-N-N-G-G-C- . This sequence occurs at all locations in over 33 000 base pairs of DNA sequence where the enzyme was found to cut DNA and nowhere else . All six of the specified bases are essential parts of the site since all groups of five of the six bases occur in the DNA sequences tested and none of them are cut by BglI . The length of the block of intervening unspecified positions must be exactly five since all other sizes between zero and 15 occur in the DNA sequences searched and none are cut by BglI . The 5'-terminal nucleotides of BglI cleaved phage G4 replicative form DNA and plasmid pER18 DNA were compared with the DNA sequences near the BglI sites on these DNAs . These results indicated that BglI cuts within the intervening unspecified region and produces single-stranded 3' termini that are three bases long . The BglI recognition site and cleavage points can thus be represented as follows: (Formula: see text) . This study of the BglI recognition site was facilitated by the use of inexpensive microcomputers . A system of programs was developed that allowed analysis of over 33 kb of DNA sequences stored on flexible magnetic disks or audio cassettes . While these programs were generally written in the higher level language BASIC, some assembly language subroutines were utilized to reduce execution time.

Gene, 1980 May, 9(3-4), 205 - 12
The DNA sequence recognised by BglI; Bickle TA et al.; The restriction enzyme BglI recognizes the DNA sequence: (Formula: see text) and cleaves it in the position shown by the arrows to leave 3' single-stranded protrusions three bases long.

Cell, 1980 May, 20(1), 245 - 54
Formation and resolution of DNA catenanes by DNA gyrase; Kreuzer KN et al.; We have discovered that DNA gyrase interlocks duplex DNA circles to form catenanes and resolves catenanes into component monomers . The reactions were inhibited by novobiocin and oxolinic acid and required ATP, Mg++ and spermidine . DNA sequence homology is not involved in catenation, since hybrid catenanes were formed efficiently between supercoiled phi X174 and Col E1 DNA . Strikingly different results were obtained with native and relaxed Col E1 DNA substrates . Up to 50-60% of input native DNA was converted into oligomeric catenanes, predominantly dimers and trimers . Relaxed substrates were instead converted into vast interlocked networks and were occasionally knotted . Optimal catenation occurred only in the narrow range of 20-35 mM KCl; increased ionic strength blocked catenation completely but activated the back reaction of decatenation . Gyrase resolved both the oligomeric catenanes and interlocked networks it produced, as well as naturally occurring catenanes . These results imply that the mechanism of gyrase involves a transient double-strand break and passage of a DNA segment through the resulting gap . Gyrase is representative of a general class of enzymes, found in both procaryotic and eucaryotic cells, that facilitate diffusion of duplex DNA segments through each other and may thereby solve topological problems arising from the replication, recombination and condensation of DNA.

J Bacteriol, 1980 May, 142(2), 701 - 13
Transposon-mediated conjugational transmission of nonconjugative plasmids; Crisona NJ et al.; When coresident with conjugative plasmid pNC21, the nonconjugative deletion F-prime pJC59, which retains the F transfer origin oriT, was transmitted to transconjugants at a frequency comparable to that of pNC21 . In addition, pJC59 was transmitted as an independent plasmid, physically separate from pNC21, an example of plasmid donation . In contrast, two plasmids that are derived from F and deleted for the oriT site, pJC61 and pML31, were transmitted at frequencies 10(4) lower than that of pNC21 . This low-frequency transmission was associated with the appearance of a new plasmid in the transconjugants . In the case of pML31, we determined that this new plasmid was a recombinant composed of pNC21 and pML31, the latter flanked by two copies of transposable element Tn3 . We believe that this recombinant plasmid was formed as an intermediate in the transposition of Tn3 from pNC21 to pML31 and was the vehicle for conjugational transmission of pML31 genes by a process known as plasmid conduction.

J Bacteriol, 1980 May, 142(2), 659 - 67
Deoxyribonucleic acid sequence of araBAD promoter mutants of Escherichia coli; Horwitz AH et al.; The controlling site region for the araBAD operon is defined, in part, by two classes of cis-acting constitutive mutations . The aralc mutations allow low-level constitutive expression of ara-BAD in the absence of the positive regulatory protein coded for by the araC gene, whereas the araXc mutations allow expression of araBAD in the absence of the cyclic adenosine monophosphate receptor protein . Six independently isolated aralc mutations and three independently isolated araXc mutations were cloned onto the plasmid pBR322 using in vitro recombinant deoxyribonucleic acid techniques and in vivo recombination between plasmid and chromosomal deoxyribonucleic acid . The location of these mutations was determined by deoxyribonucleic acid sequence analysis . All of the aralc mutations occurred at position -35 within the araBAD promoter (+1 = messenger ribonucleic acid start for araBAD) and resulted from an AT leads to GC transition . All of the araXc mutations occurred at position -10 within the araBAD promoter and resulted from a GC leads to AT transition . Models are presented to explain the mode of action of the aralc and araXc mutations.

J Bacteriol, 1980 May, 142(2), 621 - 32
Regulation of fatty acid degradation in Escherichia coli: isolation and characterization of strains bearing insertion and temperature-sensitive mutations in gene fadR; Simons RW et al.; Transposon Tn10 was used to mutagenize the fadR gene in Escherichia coli . Mutants bearing fadR:Tn10 insertion mutations were found to (i) utilize the noninducing fatty acid decanoate as sole carbon source, (ii) beta-oxidize fatty acids at constitutive rates, and (iii) contain constitutive levels of the five key beta-oxidative enzymes . These characteristics were identical to those observed in spontaneous fadR mutants . The constitutive phenotype presented by the fadR:Tn10 mutants was shown to be genetically linked to the associated transposon-encoded drug resistance . These results suggest that the fadR gene product exerts negative control over the fatty acid degradative regulon . The fadR gene of E . coli has been mapped through the use of transposon-mediated fadR insertion mutations . The fadR locus is at 25.5 min on the revised map and cotransduces with purB, hemA, and trp . Three-factor conjugational and transductional crosses indicate that the order of loci in this region of the chromosome is purB-fadR-hemA-trp . Spontaneous fadR mutants were found to map at the same location . Strains that exhibit alterations in the control of the fad regulon in response to changes in temperature were also isolated and characterized . These fadR(Ts) mutants were constitutive for the fad enzymes at elevated temperatures and inducible for these activities at low temperatures . The fadR(Ts) mutations also map at the fadR locus . These results strongly suggest that the fadR gene product is a repressor protein.

J Bacteriol, 1980 May, 142(2), 556 - 67
Location of the multivalent control site for the ilvEDA operon of Escherichia coli; Gayda DJ et al.; A strain of Escherichia coli K-12 containing a deletion extending from early in the ilvE gene toward the ilvG gene was shown to exhibit a higher expression of the downstream genes, ilvD and ilvA, than did an ilv+ strain . The elevated expression was under apparently normal ilv-specific control, however . The deletion was transferred to the ilv region of lamba h80dilv and shown by restriction endonuclease and heteroduplex analysis to extend through the deoxyribonucleic acid (DNA) shown, in the preceding paper (C . S . Subrahmanyam, G . M . McCorkle, and H . E . Umbarget, J . Bacteriol 142:547--555, 1980), to contain the ilvO determinant . The deletion was also transferred to an ilv-lac fusion strain and shown to cause an increase in beta-galactosidase formation while allowing retention of ilv-specific control . Transducing phages excised from these fusion strains with and without the ilvO determinant were compared . The phage carrying the ilvO+ determinant contained ilv DNA extending only into but not through the ilvG gene . It did not exhibit an ilv-specific control of beta-galactosidase formation . The phage carrying the deletion of ilvO but containing ilv DNA extending beyond the ilvG gene exhibited ilv-specific control of beta-galactosidase formation . It was concluded that the multivalently controlled ilv-specific promoter affecting ilv operon expression lies upstream from ilvG and that the ilvO region in the wild-type K-12 strain is a region of polarity preventing ilvG expression and reducing ilvEDA expression.

J Bacteriol, 1980 May, 142(2), 371 - 9
Cloning and restriction mapping of the trmA gene coding for transfer ribonucleic acid (5-methyluridine)-methyltransferase in Escherichia coli K-12; Ny T et al.; A hybrid plasmid from the Clarke and Carbon collection has been isolated . This plasmid carries the trmA gene of E . coli, which is necessary for the formation of 5-methyluridine (m5U,ribothymidine) present in all transfer ribonucleic acid (tRNA) chains of the organism so far sequenced . A restriction map of the argCBH-trmA regions is presented . By using cloning in vitro, the trmA gene was located on a 2.9-kilobase pair deoxyribonucleic acid (DNA) fragment . These results and comparison with lambda dargECBH transducing phages established the gene order: argECBH trmA bfe in the 88-min region of the E . coli chromosomal map . Plasmids carrying this 2.9-kilobase pair DNA fragment overproduce the enzyme tRNA(m5U)methyltransferase (EC 2.1.1.35) 20 to 40 times . When this 2.9-kilobase pair chromosomal DNA fragment was expressed in a minicell system, a polypeptide of a molecular weight of 42,000 was synthesized . This polypeptide was tentatively identified as the tRNA(m5U)methyltransferase . These results support the earlier suggestion that the trmA gene is the structural gene for the tRNA(m5U)methyltransferase.

J Lab Clin Med, 1980 May, 95(5), 654 - 9
Stimulation of cyclic 3':5'-guanosine monophosphate levels in rat spleen cells by lipopolysaccharide preparations; Bomboy JD Jr et al.; LPS greatly increases cGMP in rat fetal liver cells without affecting cAMP . The present experiments were undertaken to determine whether this effect occurs in an adult tissue, which might be exposed to LPS in vivo . Therefore cyclic nucleotides were measured in adult male rat spleen cells incubated in vitro in the presence or absence of LPS . A clear cGMP elevation was found in cultures treated with LPS . This was first evident at 2 hr and persisted for 4 hr . In contrast, cAMP was unaffected by LPS even in the presence of the phosphodiesterase inhibitor, MIX . CGMP rose progressively with LPS doses ranging from 0.8 to 20 ng, and addition of MIX potentiated the cGMP stimulatory effect . Several LPS concentrates prepared by different techniques and LPS exposed to vigorous heat treatment exhibited cGMP activity, whereas absorption of LPS with Limulus lysate abolished the cGMP response . Thus LPS increases cGMP in rat spleen cells in a dose-and time-dependent manner without affecting cAMP . Although the significance of this cGMP increase is unknown, its occurrence in spleen cells (a tissue likely to come in contact with LPS in vivo), its production by very small quantities of LPS, and the delayed but persistent nature of the effect (analogous to the aciton of cholera toxin on cAMP) are all consistent with an important role for cGMP in the action of LPS on cells.

Eur J Biochem, 1980 May, 106(1), 321 - 8
Purification and characterization of a mutant tRNA nucleotidyltransferase; McGann RG et al.; tRNA nucleotidyltransferase has been extensively purified from a mutant strain of Escherichia coli which displays greatly decreased AMP incorporation, but normal CMP incorporation . The defect in AMP incorporation is retained throughout the purification of the mutant protein . The mutant protein behaves identically to the wild-type protein with regard to elution position on various chromatographic columns, and both have similar molecular weights of about 50000 . The defect in the mutant protein is accentuated by the use of yeast tRNA rather than E . coli tRNA-C--C as substrate, by decreased pH, by increased ionic strength and by decreased divalent cation concentration . Substitution of MN2+ for Mg2+ greatly increases the relative activity of the mutant enzyme . In all these cases, CMP incorporation by the mutant enzyme remains the same as the wild-type enzyme . The Km values of the mutant enzyme for its tRNA and triphosphate substrates are unchanged, and the mutant protein is as stable as the wild type with respect to temperature inactivation . These results strongly suggest that the mutation is in the structural gene for tRNA nucleotidyltransferase, and that the mutation probably does not affect the overall structure of the mutant protein, but only a localized region near the AMP-incorporating site.

Can J Microbiol, 1980 May, 26(5), 636 - 9
The effect of trans-{Rh(4-ethylpyridine)4Cl2}Cl x 2H2O on nucleic acid and protein syntheses in Escherichia coli; Seeman SL et al.; The effect of the transition metal compound trans-{Rh(4-ethylpyridine)4Cl2}Cl x 2H2O on the syntheses of DNA, RNA, and protein has been investigated for an auxotrophic bacterial strain, Escherichia coli JS-1, incapable of thymidine, uridine, and histidine syntheses . At low concentration (7.4 x 10(-6) M), this rhodium complex interferes with normal cell division and induces the formation of filaments comparable to those observed in the presence of the cis-(NH3)2PtClx antitumour agents . Once the suppressed growth rate of the filamenting cells has been taken into account, the rhodium compound is found not to alter macromolecular synthesis . Again this is consistent with similar observations made for the platinum compounds.

J Bacteriol, 1980 May, 142(2), 547 - 55
Physical location of the ilvO determinant in Escherichia coli K-12 deoxyribonucleic acid; Subrahmanyam CS et al.; A plasmid carrying the 4,6-kilobase (kb) HindIII-derived fragment from an ilvO mutant derivative of lambda h80dilv imparted a valine-resistant phenotype on strains it carried . This fragment carries a small amount of the promoter-proximal end of ilvE, the ilvO determinant, and apparently the entire ilvG gene, which specifies the valine-insensitive acetohydroxy acid synthase . Comparable deoxyribonucleic acid (DNA) from the original lambda h80dilv did not carry the valine resistance marker . The valine-resistant phenotype was always correlated with the formation of the resistant enzymes . The ilvO determinant was shown to be carried within an approximately 600-based-pair region lying between the SalI and KpnI sites on the HindIII fragment and perhaps within the ilvG gene itself . Ribonucleic acid that hybridizes with the DNA corresponding to the ilvG gene is formed in wild-type K-12 cells . This fact, coupled with the fact that ilvG is transcribed from the same DNA strand as the ilvE, D, and A genes, led to the idea that transcription is normally initiated upstream from ilvG in both wild-type and ilvO strains . In wild-type strains either the formation or the translation of the transcript would be terminated with the ilvG gene, thus preventing expression of that gene.

J Bacteriol, 1980 May, 142(2), 384 - 90
Mutations which affect the structure and activity of colicin E3; Mock M et al.; Among 69 ColE3 mutant plasmids selected on the basis of their inability to produce an active colicin, seven (cop-1 to cop-7) were found to bear a mutation affecting the structural gene for colicin . Three of these (cop-1, cop-2 and cop-3) lead to the production of an inactive colicin molecule which has the same molecular weight as wild-type colicin E3 (67,000) . These three inactive colicins are still able to interact with the outer membrane receptor . The cop-1 protein retained the ability to inhibit protein synthesis in vitro and therefore seems specifically affected in it ability to penetrate the cell envelope . The cop-2 and cop-3 proteins lost the ability to inhibit protein synthesis in vitro, and activity which is normally associated with the C-terminal part of the colicin molecule . On the basis of this and further evidence, it is suggested that the cop-2 and cop-3 mutations affect the structure of the C-terminal part of the colicin molecule . The other four mutations (cop-4 to cop-7) lead to the production of colicin-related polypeptides of lower molecular weight (29,000 to 45,000) which display a reaction of partial immunological identity with wild-type colicin . These four polypeptides are unable to interact with the cell surface receptor . Three of these mutants are shown to carry a nonsense mutation.

Gene, 1980 May, 9(3-4), 321 - 36
Cloning of the dut (deoxyuridine triphosphatase) gene of Escherichia coli; Taylor AF et al.; Through the molecular cloning of DNA, cells were obtained that could produce a 300-fold increased level of deoxyuridine triphosphatase (dUTPase) . First, lambda pyrE-dut phages were constructed from restriction endonuclease fragments . They contained a segment of Escherichia coli DNA that spanned the structural genes for dUTPase (dut) and orotidylate pyrophosphorylase (pyrE) . The initial isolates demonstrated poor enzyme production and impaired growth . Improved enzyme yields were then obtained from large-plaque derivatives and from mutants with partial deletions of the cloned DNA . The deletion mutants were isolated after the induction of a recombinant prophage whose DNA was too large to be packaged . Finally, a 3.3-kb segment of DNA, containing the dut gene, was transferred to plasmid vectors . The recombinants and their levels of dUTPase overproduction (relative to that of wild type cells) were as follows: a thermoinducible lambda pyrE-dut phage, 45-fold (10-fold for orotidylate pyrophosphorylase); a dut-ColE1 type plasmid, 15-fold; and a thermoinducible dut-lambda-ColE1 chimera, 14-fold before induction and 300-fold after induction.

Biochim Biophys Acta, 1980 Apr 30, 607(2), 247 - 55
Mechanism of the ATP effect in the DNA repair synthesis of gamma-irradiated Escherichia coli cells; Gartner C et al.; Gamma-irradiation of Escherichia coli cells made permeable to deoxynucleoside triphosphates (dNTP) by toluene induces a repair-type DNA synthesis . As previous studies have shown ATP stimulates this DNA synthesis; we studied the mechanism of the ATP effect by analyzing the kinetics of nucleotide incorporation at various dNTP concentrations . The V values of the DNA repair synthesis rise with increasing dose (0-50 Gy); nonirradiated cells showed a negligible nucleotide incorporation . The apparent Michaelis constant KM for dNTP in the assay was 83-143 microM and the value was much higher than for a DNA polymerase reaction in vitro . ATP stimulated the DNA synthesis with concomitant decrease of KM yet unchanged V values . Similar results were obtained with a rec BC strain . We propose that the ATP effect is due to a greater affinity of dNTPs to the DNA polymerase, possibly by a stabilisation of the structural integrity of the complex DNA with repair enzymes . Activation of exonucleases by ATP could be excluded . Addition of NAD to the reaction mixture inhibits the DNA synthesis possibly by activation of ligase which closes the nicks in the DNA strand.

Biochim Biophys Acta, 1980 Apr 30, 607(2), 277 - 84
Non-coordinate regulation of enzymes involved in transfer RNA metabolism in Escherichia coli; Ny T et al.; During different steady state growth conditions in Escherichia coli the level of the three tRNA-modifying enzymes, the tRNA(m5Urd)-, tRNA(m1Guo)- and tRNA(mam5s2Urd)methyltransferase and of five aminoacyl-tRNA synthetases, the leucyl-, valyl-, isoleucyl-, arginyl- and threonyl-tRNA-synthetase, has been determined . It is shown that those two classes of tRNA affecting enzymes are not coordinately regulated and that even within these two groups of enzymes the constituents are regulated independently of each other . Furthermore it is demonstrated that none of the aminoacyl-tRNA synthetases and only one of the three tRNA-methyltransferases, the tRNA(m5Urd)methyltransferase, is under control of the relA+-gene.

Biochemistry, 1980 Apr 29, 19(9), 1857 - 61
Photoaffinity labeling of the adenosine cyclic 3',5'-monophosphate receptor protein of Escherichia coli with 8-azidoadenosine 3',5'-monophosphate; Aiba H et al.; Photoaffinity labeling of the cAMP receptor protein (CRP) of Escherichia coli with 8-azidoadenosine 3',5'-monophosphate (8-N3cAMP) has been demonstrated . 8-N3cAMP is able to support the binding of (3H)d(I-C)n by CRP, indicating that it is a functional cAMP analogue . Following irradiation at 254 nm, (32P)-8-N3cAMP is photocross-linked to CRP . Photolabeling of CRP by (32P)-8-N3cAMP is inhibited by cAMP but not by 5'AMP . The data indicate that (32P)-8-N3cAMP is covalently incorporated following binding at the cAMP binding site of CRP . The (32P)-8-N3cAMP-CRP digested with chymotrypsin was analyzed by NaDodSO4-polyacrylamide gel electrophoresis . Of the incorporated label, one-third remains associated with the amino-proximal alpha core region of CRP {Eilen, E., Pampeno, C., & Krakow, J.S . (1978) Biochemistry 17, 2469} which contains the cAMP binding domain; the remaining two-thirds of the label associated with the beta region are digested . Limited proteolysis of the (32P)-8-N3cAMP-CRP by chymotrypsin in the presence of NaDodSO4 shows the radioactivity to be distributed between the molecular weight 9500 (amino-proximal) and 13,000 (carboxyl-proximal) fragments produced . These results suggest that a part of the carboxyl-proximal region is folded over and close enough to the cAMP binding site to be cross-linked by the photoactivated (32P)-8-N3cAMP bound at the cAMP binding site.

J Biol Chem, 1980 Apr 25, 255(8), 3707 - 12
Accumulation of glyceride-containing precursor of the outer membrane lipoprotein in the cytoplasmic membrane of Escherichia coli treated with globomycin; Hussain M et al.; The protein accumulated in the cell envelope of Escherichia coli treated with globomycin was identified as the precursor of the outer membrane lipoprotein . The prolipoprotein was almost exclusively localized in the cytoplasmic membrane . The prolipoprotein could be immunoprecipitated with antilipoprotein immunoglobulin and could be chased to the lipoprotein in both in vivo and in vitro . Globomycin inhibited the chase . The prolipoprotein contained glycerol and fatty acid residues, whereas no free sulfhydryl group was detected in it . From these results, it is concluded that the prolipoprotein possesses a glyceride which is covalently bound to the cysteine residue in the peptide as the lipoprotein does and that the removal of signal peptide takes place after the modification . The inhibition of bacterial growth with increasing concentrations of globomycin was accompanied by a gradual increase in the accumulation of the prolipoprotein . Furthermore, growth of the lipoprotein-negative mutant was highly resistant to globomycin . These results strongly indicate that the accumulation of the prolipoprotein in the cytoplasmic membrane causes the death of cells.

J Biol Chem, 1980 Apr 25, 255(8), 3536 - 41
Regulation of RNA polymerase synthesis . Conditional lethal amber mutations in the beta subunit gene; Little R et al.; Amber mutations in the rpoB gene specifying the beta subunit of RNA polymerase coupled with conditional amber suppressors were used to restrict the synthesis of core RNA polymerase in strains of Escherichia coli . Such a restriction stimulated transcription of genetic units containing RNA polymerase subunit genes . Within the L10 transcription unit (genetic structure: promotor (PL10), rplJ (L10), rplL (L7/L12), attenuator, rpoB (beta), rpoC (beta'), terminator), the initiation of transcription at the promotor was enhanced and termination at the transcription attenuator was relaxed . Transcription of the genetic unit containing the rpoA gene (alpha) was also enhanced . In the strain containing a non-polar amber mutation, the synthesis rate of the beta' subunit protein during the restriction correlated with the level of transcription of the beta and beta' genes . In contrast, synthesis of L7/L12 ribosomal protein remained essentially unaltered in spite of the elevated levels of L10-L7/L12 mRNA.

J Biol Chem, 1980 Apr 25, 255(8), 3263 - 5
Beta-ketoacyl-acyl carrier protein synthase II of Escherichia coli . Evidence for function in the thermal regulation of fatty acid synthesis; Garwin JL et al.; Cvc- mutants of Escherichia coli are deficient in the synthesis of cis-vaccenic acid and in the temperature control of fatty acid synthesis . In this communication, it is demonstrated that these mutants lack beta-ketoacyl-acyl carrier protein synthase II . The deficiencies in cis-vaccenate synthesis and synthase II are shown to be due to a lesion in the same gene, fabF . Lesions in the fabF gene are found to affect growth only when the strain also carries a lesion in the fabB gene, the structural gene for beta-ketoacyl-acyl carrier protein synthase I.

J Biol Chem, 1980 Apr 25, 255(8), 3227 - 9
Sulfhydryl groups of Escherichia coli ribosomal protein S1 . Location along the polypeptide chain; Subramanian AR; The location of the functionally important -SH groups of Escherichia coli ribosomal protein S1 along the polypeptide chain has been determined using a cysteine-specific cleavage procedure . The two -SH groups of S1 are located at 57% and 67% of the polypeptide chain length from the NH2 terminus . The -SH group farther from the NH2 terminus is shown to be the more reactive one . Two truncated derivatives of S1 (S1-F1 and m1-S1) both contain two -SH groups . It has previously been shown that S1-F1 (which lacks the NH2-terminal region of S1) is inactive in unfolding nucleic acids, just as the N-ethylmaleimide derivative of S1 . The present results therefore show that the formation and functioning of the nucleic acid unfolding domain of protein S1 requires the -SH group(s) as well as the NH2-terminal region.

Nucleic Acids Res, 1980 Apr 25, 8(8), 1873 - 91
Precursors to 16S and 23S ribosomal RNA from a ribonuclear III-strain of Escherichia coli contain intact RNase III processing sites; Gegenheimer P et al.; Escherichia coli cells lacking the ribosomal RNA processing enzyme RNase III do no excise the normal RNA precursors p16a (17S) and p23a from nascent rRNA transcripts . These cells produce, instead, slightly larger p16b and p23b precursors . Digestion of p16b or p23b rRNA with RNases A plus T1 yields double-stranded fragments composed of sequences, located at both the 5' and the 3' end regions of the molecules . The terminal duplex, or stem, of p16b contains sequences surrounding the site of RNase III processing which is wild-type cells produces p16a rRNA: the p23b stem likewise contains an intact RNase III cleavage site . The results confirm our earlier prediction for the structure of rRNA transcripts, and also yield a definite secondary structure for the p16 stem, which was not uniquely determined by the corresponding DNA sequence . These experiments demonstrate the absence of significant RNase III processing activity in rnc-105 strains of E . coli, and implicate the participation of another endonuclease(s) in rRNA processing in mutant and wild-type cells.

Nucleic Acids Res, 1980 Apr 25, 8(8), 1693 - 707
Two rearranged immunoglobulin kappa light chain genes in one mouse myeloma; Steinmetz M et al.; The organization of immunoglobulin gene segments coding for kappa light chains has been studied in uncloned and cloned DNA from mouse liver and a mouse myeloma . It is known that the C (constant, ref . 2) gene segment is present in the tumor DNA on two EcoRI fragments of 14 and 20 kb and in liver DNA on a 15 kb fragment . The 14 kb myeloma and the 15 kb liver fragment have been cloned previously . Here we report on the cloning of the 20 kb myeloma fragment and present detailed restriction maps covering about 22 kb of DNA surrounding the C gene segment in liver and tumor DNA . The region on the 20 kb fragment has been localized where a DNA rearrangement had occurred . The presence of two rearranged kappa light chain genes in one tumor is discussed in regard to the molecular basis of allelic exclusion.

J Biol Chem, 1980 Apr 25, 255(8), 3726 - 35
The effect of divalent cations on the mode of action of DNase I . The initial reaction products produced from covalently closed circular DNA; Campbell VW et al.; The effect of different divalent metal ions on the hydrolysis of DNA by DNase I was studied with an assay which distinguishes between cleavage of one or both strands of the DNA substrate during initial encounters between enzyme and DNA . Using covalently closed superhelical SV40(I) DNA as substrate, initial reaction products consisting of relaxed circles or unit-length linears are resolved by electrophoresis of radioactively labeled DNA in agarose gels . Only in the presence of a transition metal ion, such as Mn2+ or Co2+, and only under certain reaction conditions, is DNase I able to cut both DNA strands at or near the same point, generating unit-length linears . This ability to cut both DNA strands is inhibited by such factors as temperature decrease, the addition of a monovalent ion or another divalent cation which is not a transition metal ion, or a reduction in the number of superhelical turns in the DNA substrate . All of these factors lead to a winding of the duplex helix and antagonize the unwinding of the duplex promoted by transition metal ion binding . Transition metal ions may thus convert the DNA substrate locally to a form in which DNase I can introduce breaks into both strands . In the presence of Mg2+, DNase I introduces single strand nicks into SV40(I), generating exclusively the covalently open, relaxed circular SV40(II) as the initial product of the reaction . In the presence of Mn2+, DNase I generates as initial products a mixture of SV40(II) and unit-length SV40 linear DNA molecules, formed by two nicks in opposite strands at or near the same point in the duplex . These circular SV40(II) molecules consist of two types . A minority class is indistinguishable from the nicked SV40(II) produced by DNase I in the presence of Mg2+ . The majority class consists of molecules containing a gap in one of the two strands, the mean length of the gap being 11 nucleotides . The SV40(L) molecules produced in the presence of Mn2+ appear to have single strand extensions at one or both ends.

J Biol Chem, 1980 Apr 25, 255(8), 3581 - 4
Actinomycin D binds with highest affinity to nonribosomal DNA; Khan MM et al.; Based on previous evidence (T.J . Lindell (1976) Nature 263, 347-350 and T.J . Lindell, A.F . O'Malley, and B . Puglisi (1978) Biochemistry 17, 1154-1160) it was anticipated that actinomycin D in a low concentration would bind to DNA which is involved in the regulation of rRNA transcription in eukaryotes . This was examined by digestion of rat (liver) DNA with EcoRI, adding {3H}actinomycin D (0.004 microgram/ml) and resolution of the restriction fragments by RPC-5 chromatography . Labeled actinomycin D was found to bind with highest affinity to a single fraction consistently eluting at 0.63 M KCl . A similar digestion and fractionation of nucleolar DNA, which is enriched in rDNA sequences, did not reveal a similar high affinity binding of actinomycin D . This fraction of DNA which binds actinomycin D with highest affinity did not contain any rDNA as evidenced by hybridization with {32P}rRNA . Therefore, at the concentration of 0.004 microgram/ml, actinomycin D does not selectively bind to rDNA as evidenced by two independent criteria . Whether this high affinity actinomycin D-binding DNA has any function in the regulation of rRNA transcription remains to be determined.

Biochim Biophys Acta, 1980 Apr 24, 597(3), 502 - 17
31P nuclear magnetic resonance and freeze-fracture electron microscopy studies on Escherichia coli . II . Lipopolysaccharide and lipopolysaccharide-phospholipid complexes; van Alphen L et al.; 1 . Freeze-fracture electron microscopy and 31P-NMR spectroscopy on native and electrodialyzed lipopolysaccharide from Escherichia coli K12 cells, both above and below the phase transition temperature, are described . 2 . Freeze-fracture electron microscopy of native lipopolysaccharide shows ribbon-like structures below (0 and 22 degrees C) and large vesicles above (37 degrees C) the phase transition temperature . Electrodialyzed lipopolysaccharide (sodium salt) occurs in ribbon-like structures at 0, 22 and 37 degrees C if sodium lipopolysaccharide is hydrated in water . If sodium lipopolysaccharide is hydrated in Tris-HCL/NaCl buffer these ribbon-like structures occur only below the phase transition temperature . Above the phase transition temperature stacked sheets are observed . Moreover, in the latter case, the fracture planes contain particles and pits . Upon etching, sodium lipopolysaccharide when hydrated in water appears to form rods and when hydrated in buffer appears to form mainly stacked lamellae both above (37 degrees C) and below (0 degrees C) the phase transition temperature . 3 . High resolution 31P-NMR spectra show that the chemical shifts of the phosphorus atoms in native lipopolysaccharide differ from those in electrodialyzed lipopolysaccharide, probably due to conformational and compositional (the disappearance of ions and (poly)electrolytes) changes . The 31P-NMR spectra of native lipopolysaccharide dispersed in Tris-HCL/NaCl buffer are very broad at 20 and at 40 degrees C indicating little motion . At 22 degrees C electrodialyzed lipopolysaccharide also gives a broad spectrum; at 40 degrees C the spectrum is narrower, indicating more motion, and two peaks are visible . After dispersion in H2o and subsequent addition of buffer, the spectrum of electrodialyzed lipopolysaccharide is narrow both at 20 and 40 degrees C, which can be correlated with the rods observed in freeze etching . After treatment with Ca2+, electrodialyzed lipopolysaccharide shows a very broad spectrum at 40 degrees C probably due to immobilization of the lipopolysaccharide . 4 . Freeze-fracture electron microscopy and 31P-NMR spectroscopy of liposomes consisting of native lipopolysaccharide and total phospholipids indicate that the phospholipids and the lipopolysaccharide are mainly organized in bilayers . Lipopolysaccharide in such liposomes undergoes more motion than in the absence of phospholipids . Ca2+ does not influence this behaviour.

Biochim Biophys Acta, 1980 Apr 24, 597(3), 492 - 501
31P nuclear magnetic resonance and freeze-fracture electron microscopy studies on Escherichia coli . I . Cytoplasmic membrane and total phospholipids; Burnell E et al.; 1 . At the growth temperature the total phospholipids isolated from Escherichia coli cells give rise to 31P-NMR spectra which indicate the existence of lamellar, isotropic and hexagonal phases . These phases are also detected by freeze fracture electron microscopy . In particular, the isotropic phase may contain lipidic particles (possibly inverted micelles) associated with the lamellar phase . 2 . The cytoplasmic membrane isolated from E . coli cells grown at 37 degrees C is mainly lamellar at 25 degrees C, whereas at 37 and 45 degrees C the presence of some almost isotropic phospholipid motion is indicated . The possible significance of the isotropic phase for the functioning of the cytoplasmic membrane is discussed.

Biochim Biophys Acta, 1980 Apr 24, 597(3), 518 - 32
31P nuclear magnetic resonance and freeze-fracture electron microscopy studies on Escherichia coli . III . The outer membrane; Burnell E et al.; 1 . The outer membrane of a phospholipase A-deficient mutant of Escherichia coli K12, isolated without the use of EDTA and lysozyme, showed the same freeze-fracture morphology as that seen in cells and remained stable for hours as observed by 31P-NMR . 2 . 31P-NMR spectroscopy of the isolated outer membranes revealed that the lipopolysaccharide exists in the same physical state as in phospholipid-lipopolysaccharide liposomes and is most probably arranged in a bilayer at 37 degrees C . The outer membrane contains most or all of the phospholipids at 37 degrees C, and all the phospholipids at 20 degrees C, as a bilayer . 3 . The 31P-NMR spectroscopy of the outer membranes from a mutant strain lacking the major outer membrane protein b, c and d (60% of the total outer membrane protein) yields virtually the same spectrum as the wild-type outer membranes, although most of the particles and pits which were observed in wild-type outer membranes in freeze-fracture electron microscopy were absent . 4 . Whereas treatment of wild-type outer membranes with calcium ions has no effect on the 31P-NMR spectrum, treatment with EDTA results in more motion of the lipopolysaccharide.

Biochemistry, 1980 Apr 15, 19(8), 1656 - 62
Functional heterogeneity of Escherichia coli ribonucleic acid polymerase holoenzyme; Travers AA et al.; On zone sedimentation Escherichia coli RNA polymerase holoenzyme exhibits functional heterogeneity with respect to template preference, regulation by ppGpp, and affinity for fMet-tRNA . The template preference of a subpopulation of RNA polymerase molecules correlates with both its sedimentation position and its ability to respond to effectors of polymerase selectivity . Incubation of such functionally distinct populations of enzyme molecules at physiological temperatures results in functional and structural equivalence . We suggest that RNA polymerase normally exists as a mixture of interconvertible forms and that promoter selection can be controlled by varying the number and proportions of forms present.

Biochemistry, 1980 Apr 15, 19(8), 1651 - 6
Translation initiation factor 2 alters transcriptional selectivity of Escherichia coli ribonucleic acid polymerase; Travers AA et al.; Preparations of translation initiation factor IF-2 strongly stimulate the production of rRNA by Escherichia coli RNA polymerase but have little effect on the synthesis of other RNA species . The factor alters the sedimentation characteristics of RNA polymerase holoenzyme . We suggest a mechanism by which IF-2 alters the pattern of transcriptional selectivity of RNA polymerase.

Am J Obstet Gynecol, 1980 Apr 15, 136(8), 976 - 9
Single-dose and multidose prophylaxis in vaginal hysterectomy: a comparison of sodium cephalothin and metronidazole; Hamod KA et al.; A total of 79 patients underwent vaginal hysterectomy and were randomly assigned to three regimens of prophylactic antibiotics: multidose intravenous sodium cephalothin, single-dose intravenous sodium cephalothin, and single-dose oral metronidazole . Control groups were selected from two previous studies conducted at our institution . The incidence rates of infectious morbidity following all three regimens of antibiotics were substantially lower than in the control groups . There was no statistically significant difference in the incidence of standard febrile morbidity and serious pelvic infections among the three groups . The fever index was lowest in the single-dose sodium cephalothin group.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1675 - 91
Azidopolynucleotides as photoaffinity reagents; Cartwright IL et al.; Polynucleotides containing adenosine and 8-azidoadenosine or inosine and 8-azidoinosine residues have been prepared from mixtures of nucleoside diphosphates using polynucleotide phosphorylase from Escherichia coli . These copolymers can form complexes with polyuridylic or polycytidylic acids respectively . Single stranded poly(adenylic, 8-azidoadenylic acid) {poly(A,z8A)} has been used as a photoaffinity reagent to explore the subunit topography of RNA polymerase from E . coli.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1561 - 73
Construction and characterization of a cDNA clone containing a portion of the bovine prolactin sequence; Nilson JH et al.; Poly(A)-containing RNA from the bovine anterior pituitary has been used as a template for the enzymatic synthesis of double-stranded cDNA . The resulting double-stranded cDNA was inserted into the Pst I site of pBR322 with the oligo(dG)-oligo(dC) tailing technique and subsequently cloned in E . coli chi 1776 . Clones containing sequences complementary to prolactin mRNA were identified by colony hybridization with partially purified prolactin cDNA . A 250 base pair sequence from one prolactin positive clone was extensively characterized and shown to contain the coding information for amino acids 119-192 of authentic bovine prolactin . The recombinant DNA from this clone was covalently attached to diazotized aminocellulose and used to purify prolactin mRNA from a mixture of mRNAs.

Eur J Pharmacol, 1980 Apr 11, 63(1), 47 - 56
Blood levels of 6-oxo-prostaglandin F 1 alpha during endotoxin-induced hypotension in rabbits; Bult H et al.; Levels of 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha), the non-enzymic degradation product of prostacyclin, were measured in arterial blood from anaesthetized rabbits, before and after intravenous (i.v.) administration of endotoxin (Lipopolysaccharine W E . coli 0111:B4, 5 mg/kg) . 6-Oxo-PGF1 alpha was assessed by radioimmunoassay after extraction and separation by thin-layer chromatography . The basal concentration of 6-oxo-PGF1 alpha in blood was less than 100 mg/ml in 19 out of 20 rabbits . This indicates that the level of circulating prostacyclin is generally below 100 pg/ml . The administration of endotoxin induced a biphasic hypotension, and increased levels of 6-oxo-PGF1 alpha were found in all endotoxin-treated animals during the secondary hypotension after 60 and 120 min . Pretreatment with indomethacin (2.5 mg/kg) prevented the secondary fall in arterial blood pressure and significantly suppressed the rise in 6-oxo-PGF1 alpha . However, indomethacin failed to alter the endotoxin-induced thrombocytopenia and did not modify the endotoxin-induced platelet aggregation in vitro . It is concluded that prostacyclin contributed to the secondary hypotension which accompanied the i.v . administration of endotoxin . Thromboxane A2 seems not to be of primary importance in the endotoxin-platelet interaction.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1445 - 57
Yeast mitochondrial methionine initiator tRNA: characterization and nucleotide sequence; Canaday J et al.; Two methionine tRNAs from yeast mitochondria have been purified . The mitochondrial initiator tRNA has been identified by formylation using a mitochondrial enzyme extract . E . coli transformylase however, does not formylate the yeast mitochondrial initiator tRNA . The sequence was determined using both 32P-in vivo labeled and 32P-end labeled mt tRNAf(Met) . This tRNA, unlike N . crassa mitochondrial tRNAf(Met), has two structural features typical of procaryotic initiator tRNAs: (i) it lacks a Watson-Crick base-pair at the end of the acceptor stem and (ii) has a T-psi-C-A sequence in loop IV . However, both yeast and N . crassa mitochondrial initiator tRNAs have a U11:A24 base-pair in the D-stem unlike procaryotic initiator tRNAs which have A11:U24 . Interestingly, both mitochondrial initiator tRNAs, as well as bean chloroplast tRNAf(Met), have only two G:C pairs next to the anticodon loop, unlike any other initiator tRNA whatever its origin . In terms of overall sequence homology, yeast mitochondrial tRNA(Met)f differs from both procaryotic or eucaryotic initiator tRNAs, showing the highest homology with N . crassa mitochondrial initiator tRNA.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1535 - 50
Structure of a promotor on plasmid pMB9 derived from plasmid pSC101; Pannekoek H et al.; The DNA sequence of a 354 basepair EcoRI-HindIII fragment of plasmid pMB9 which has originally been derived from plasmid pSC101 has been resolved . This fragment contains a promoter for transcription directed towards the EcoRI site . Escherichia coli RNA polymerase binds to a region within the EcoRI-HindIII fragment which contains the heptamer 5' TATGGTG (132-126) and the duodecamer 5' TGATGAACATCA (158-147) . Based on commonalities with other promotors these DNA sequences probably function as, respectively, "binding site" and "recognition site" . Furthermore, this fragment harbours a translation reading frame free of nonsense codons and at about 25 basepairs from the indicated heptamer a nucleotide sequence which meets with the requirements for initiation of translation . By heteroduplex mapping it was shown that the EcoRI-HindIII fragment has been derived from a region near or within the origin of replication of pSC101 . The copynumber of plasmids containing the EcoRI-HindIII fragment is two-fold lower than that of plasmids lacking this fragment . This effect might be related to the original function of this fragment on plasmid pSC101.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1505 - 19
Electron microscopic demonstration of the presence of amplified sequences at the 5'-ends of the polyoma virus late mRNAs; Zuckermann M et al.; Electron microscopic techniques were used to examine the structure of the leader sequences at the 5'-ends of the late polyoma virus mRNAs . The three late mRNA's were partially purified and hybridized to an E . coli plasmid containing two polyoma virus genomes inserted in tandem . The hybrids were spread by the cytochrome c-formamide technique and visualized in the electron microscope . These studies revealed that whereas the body of a given mRNA molecule can hybridize with only one of the two corresponding body sequences in the two adjacent viral genomes, the leader of the same mRNA molecule can hybridize with both copies of the leader sequence-specific DNA . The mVP1 and mVP3 RNA species thus generated hybrids containing two loops, while mVP2 molecules formed hybrids containing one loop . Hence, the leaders of the three polyoma virus late mRNA species must contain two or more repeats of a sequence transcribed from a unique DNA segment . Length measurements showed that most leaders in the late mRNA's consist of at least 200 nucleotides and some contain up to 500 nucleotides, whereas the basic repeat sequence contains about 60 nucleotides.

Nucleic Acids Res, 1980 Apr 11, 8(7), 1459 - 73
The nucleotide sequence surrounding the replication origin of the cop3 mutant of the bacteriocinogenic plasmid Clo DF13; Stuitje AR et al.; The nucleotide sequence from about 100 base-pairs downstream to about 600 base pairs upstream the CloDF13 replication origin has been determined . A comparison of this sequence with the corresponding ColE1 origin sequence reveals that: The sequence at the origin of replication is conserved . There are large differences in the nucleotide sequence downstream the replication origin, whereas there is a large homology in the region of about 410 base-pairs upstream the replication origin . This conserved region might code for a largely homologous basic, arginine rich polypeptide of about 45 amino-acids, for both ColE1 and CloDF13 . Although there are large differences in the primary structure of the region coding for the 100 nucleotide RNA, the secondary structure of this region seems to be conserved.

Biochim Biophys Acta, 1980 Apr 10, 597(2), 274 - 84
Measurements of membrane potentials in Escherichia coli K-12 inner membrane vesicles with the safranine method; Huttunen MT et al.; The use of safranine, a positively-charged dye, as a probe for the determination of membrane potentials in Escherichia coli vesicles has been studied . 1 . Shifts in the spectrum of safranine were observed during induction of potassium ion diffusion potentials with valinomycin or during oxidation of formate by vesicles prepared from cells of E . coli K-12 or ML 308-225 subjected to anaerobic growth with nitrate . The extent of the valinomycin-dependent spectral change correlated linearly with the magnitude of the K+ equilibrium potential, as calculated from the Nernst equation, from 50 to 160 mV (interior negative) . The formate-induced changes could also be calibrated by increasing the concentration of potassium in the presence of valinomycin, after the formation of formate-dependent responses . In this case, results identical to those obtained with the first method were obtained . 2 . O2 or nitrate-dependent oxidation of formate resulted in a membrane potential of the order of 170 mV . The oxidation of ascorbate-reduced N-methylphenazonium methosulphate resulted in a potential of similar magnitude, but anaerobically with nitrate only a small but definite potential was formed . 3 . The water-soluble quinones, duroquinone and menadione, could produce membrane potentials when used in their oxidized or reduced forms in the presence of formate or nitrate (or oxygen) . 2-Hydroxy-1,4-naphthoquinone was not only ineffective but was found to be inhibitory . 4 . N,N'-dicyclohexylcarbodiimide at suitable concentrations increased the rate of formation and the extent of membrane potentials induced by respiration or by artificial means.

J Biol Chem . 1980 Apr 10;255(7):3042 8.
The status of glycolaldehyde in the biosynthesis of vitamin B6; Vella GJ et al.; Competition experiments, employing 14C-labeled samples of glycerol and glycolaldehyde, indicate that in Escherichia coli B there are two independent pathways leading to pyridoxal . In mutant WG2 (and therefore presumably also in the wild strain) the major pathway utilizes glycerol and related trioses as the sole carbon source in the construction of the C8N skeleton of pyridoxol: C-1, -3 of glycerol yields C-2', -3, -4', -5' and -6, C-2 of glycerol yields C-2, -4, and -5 of the vitamin . In the minor pathway glycolaldehyde and not glycerol supplies C-5 and C-5' of pyridoxol, while glycerol is the source of the other 6 carbon atoms . In mutant WG3 the major route is blocked and the "glycolaldehyde pathway" becomes the sole source of vitamin B6.

J Biol Chem, 1980 Apr 10, 255(7), 2897 - 901
A temperature-sensitive single-stranded DNA-binding protein from Escherichia coli; Meyer RR et al.; A temperature-sensitive single-stranded DNA-binding protein (SSB) has been purified from mutant Escherichia coli (ssb-1) cells by use of affinity chromatography on blue dextran-Sepharose . An altered amino acid sequence in the mutant protein is apparent in tryptic digests, confirming that the ssb mutation is in the structural gene . The mutant protein is less effective than the wild type in protecting single-stranded DNA from nuclease S1 digestion and in inhibiting DNA-dependent ATPases . The purified protein supports replication of phage G4 DNA in vitro at 30 degrees C, although higher levels of mutant protein, 4-fold higher than wild type, are needed to do so . The mutant protein becomes less active in supporting replication above 30 degrees C and becomes inactive at 42 degrees C within 1 min . Activity is restored upon return to 20 degrees C . Despite its temperature sensitivity in vivo and in vitro, the mutant binding protein can renature fully after exposure to 100 degrees C . Thus, the mutant protein is both heat-stable and functionally temperature-sensitive.

J Biol Chem, 1980 Apr 10, 255(7), 2867 - 9
The use of 6-labeled glucose to assess futile cycling in Escherichia coli; Chambost JP et al.; To assess the "futile cycle" fructose-6-P leads to fructose-1,6-P2 leads to fructose-6-P in Escherichia coli we have grown the cells on {6-14C}glucose and determined label in the 1-position of glucose obtained from glycogen . In a variety of strains, including a wild type and a mutant without fructose diphosphatase, 1-position labeling was negligible . But there was little label in the 1-position of fructose-1,6-P2 either, which shows that hexose diphosphate and triose-P are not in equilibrium in this organism . Therefore, the lack of 1-position labeling in glycogen does not necessarily indicate lack of futile cycling . One strain, however, a temperature-sensitive glyceraldehyde-3-P dehydrogenase mutant grown at permissive temperature, gave substantial labeling of the 1-position of fructose-1,6-P2 . In this strain 1-position labeling in glycogen was low, indicating minimal futile cycling.

J Biol Chem, 1980 Apr 10, 255(7), 2848 - 54
Dissociation and reconstitution of membranes synthesizing the peptidoglycan of Escherichia coli . Lipid dependence of the synthetic enzymes; Taku A et al.; The peptidoglycan synthetic enzymes can be dissociated with cholate and LiCl into components with mobilities on a gel filtration column in the same ranges as bovine serum albumin . The active enzymes can be separated further from the lipids necessary for synthesis by precipitation with ammonium sulfate . The needed lipids stable to hydrolysis with base . A protein needed for peptidoglycan polymerization can be separated from the other synthetic enzymes by hydroxylapatite chromatography.

Lab Invest, 1980 Apr, 42(4), 450 - 6
Bone solubilization by mononuclear cells; McArthur W et al.; Mononuclear cells derived from chicken peripheral blood or from thioglycollate-induced mouse peritoneal exudates were found to cause calcium release from devitalized homologous bone in vitro . These mononuclear cells with osteolytic activity were adherent to plastic surfaces and were identified as being macrophages by cell surface markers and histochemical staining . Other mononuclear cells such as chicken thymocytes, nonadherent peripheral blood mononuclear cells, and chick embryo fibroblasts did not cause bone dissolution . In parallel with the active solubilization of bone mineral, 14C-label was also released from devitalized calvaria prelabeled with 14C-proline . Macrophages, inactivated by repeated freezing and thawing as well as those cultured in the presence of iodoacetate, did not solubilize bone in vitro . The degree of bone solubilization was directly related to the numbers of macrophages per culture as well as the duration of the culture period . Powdered devitalized homologous bone was used in most experiments, but macrophages were also able to solubilize bone material in vitro from devitalized calvaria and bone slabs . The addition of Escherichia coli lipopolysaccharide to cultures of bone and macrophages significantly increased the levels of calcium released from bone . The addition of parathyroid hormone and calcitonin had no effect on macrophage-mediated bone dissolution . These results suggest that viable macrophages have osteolytic activity and that this activity is modulated by an inflammatory mediator, endotoxin.

Morphol Igazsagugyi Orv Sz, 1980 Apr, 20(2), 88 - 93
{Light and electron microscopic study of the seminiferous tubules in experimental malacoplakia}; Jarmay K et al.; Behaviour of the epithelium of seminiferous tubules and interstitial tissue was studied in malacoplakia induced by administration of an extract of E . coli . Necrosis of the epithelium of seminiferous tubules developed immediately and it was replaced by granulocytes, and histiocytes, phagocytizing both, bacterial extract administered and disintegrated cells . Tunica propria was thickened by inflammatory cells . Hansemann cells were observed not only in the interstitium but between the layers of the tunica propria and on the place of the necrotized epithelium of the seminiferous tubules . Although Sertoli cells possess phagocytizing activity it could not be proved, that Hansemann cells are taking their origin from them.

Genetika, 1980 Apr, 16(4), 597 - 601
{Effect of the ts 15 mutation of transcription termination factor rho on expression of the uridine phosphorylase gene of Escherichia coli}; Gol'tsmaier TA et al.; The expression of nucleoside-catabolizing genes was studied in two isogenic strains, SA1030(rho+) and AD1600(rho ts 15) . The deo-enzymes activities do not differ markedly in these two strains, though when cells were grown on glycerol medium the deo-enzymes level appeared to be higher than on glucose medium . The synthesis of uridine phosphorylase in AD1600 strain was found to be constitutive . It was found also that the cytR regulation system was not altered in AD1600 strain and a wild-type allele of udp gene was present in the genome of AD1600 strain . A conclusion is made that constitutive synthesis of uridine phosphorylase is due to the presence of rho ts 15 mutation in the genome of the strain AD1600.

J Gen Microbiol, 1980 Apr, 117(2), 377 - 82
Two genes affecting glucarate utilization in Escherichia coli K12; Roberton AM et al.; D-Glucarate is transported into Escherichia coli K12 by an inducible system at an apparent rate of 7 to 15 nmol min-1 (mg dry mass)-1 . The apparent Km for uptake is 16 muM . The system is induced by growth on glucarate or glycollate . Galactarate competes with glucarate for the uptake system . A mutation (gar A) was isolated in which activities of glucarate transport and glucarate dehydratase and the ability to grow on glucarate or galactarate are all impaired . The mutation maps at min 16 . Another mutation of indistinguishable phenotype is probably a deletion of the genes garB and tonA at min 3.5.

Rev Bras Pesqui Med Biol, 1980 Apr, 13(1-3), 31 - 6
{Infant mouse test for the assay of thermostable (ST) enterotoxin from Escherichia coli . Histological studies and influence of mice age (author's transl)}; Franceschi AP et al.; Mices with different ages ranging 1 to 60 days old were inoculated with thermostable (ST) enterotoxin of Escherichia coli, either by intragastric injection through the abdominal wall or by intubation . Doses were proportional to body weight and values obtained for intestines/carcass weight ratios (RI/C) of inoculated mice showed that mice remained susceptible to the enterotoxin up to 16 days old, with RI/C values equal or greater than 0.085 . Older mice were completely resistant to ST activity as RI/C values demonstrated . Histological observations showed that whole gut's fixation of inoculated mice was absolutely necessary since any handling of intestinal loops evoked artifactual alterations . Even though, alterations were found, probably of mechanical nature, caused by intestinal distension consequent to the increased fluid volume into gut's lumen . These alterations did not differ from those observed for both cholera and LT-E . coli enterotoxins, characterized by lymphatic and blood vascular dilatation within mucosae lamina propria, eventually shrinkage of lamna propria just below the epithelium as well epithelial's vacuolizations.

Prostaglandins Med, 1980 Apr, 4(4), 215 - 25
Beneficial actions of imidazole in endotoxin shock; Smith EF 3rd et al.; The effects of imidazole were studied in anesthetized cats during endotoxin shock . Imidazole (25 mg/hg/hr) was administered 30 minutes after intravenous injection of E . coli endotoxin (5 mg/kg) . The degree of the severity of the shock state was assessed by mean arterial blood pressure (MABP), and by plasma cathepsin D and MDF activities . Analysis of thromboxane B2 concentrations during shock was also performed by radioimmunoassay . Administration of imidazole to cats given endotoxin partially prevented the decrease in MABP of endotoxin shock . Imidazole significantly prevented the increase in plasma cathepsin D and MDF activities . Thus, infusion of imidazole resulted in metabolic and hemodynamic improvement during endotoxin shock . The mechanism of imidazole protection appears to be via lysosomal membrane stabilization, stimulation of cardiac function and possibly by antagonizing the biochemical effects of endotoxin administration, rather than by inhibition of thromboxane synthesis . Data obtained using imidazole to block thromboxane synthesis in shock states must be interpreted with caution.

Biochemistry, 1980 Apr 1, 19(7), 1458 - 62
Effects of sodium and lithium ions on the potassium ion transport systems of Escherichia coli; Sorensen EN et al.; The effects of the cations choline, Li+, and the Na+ on the TrkA and Kdp K+ transport systems in Escherichia coli were studied by observing the accumulation of 204Tl+ and K+ . Tl+ uptake via the TrkA system was stimulated by Na+ but not Li+ when compared to choline . A similar effect was observed for K+ transport via the TrkA system . On the other hand, Tl+ uptake via the Kdp system was stimulated more by Li+ than by Na+ when compared to choline . In addition, Li+ enhanced the effectiveness of Rb+ as an inhibitor of Tl+ uptake via the Kdp system . Na+, however, was a more effective stimulator of K+ transport via the Kdp system than Li+ . We suggest that Na+ may be involved in the mechanisms of K+ transport via the TrkA and Kdp systems in E . coli.

Biochemistry, 1980 Apr 1, 19(7), 1397 - 402
Kinetics of anticooperative binding of phenylalanyl-tRNAPhe and tRNAPhe to phenylalanyl-tRNA synthetase of Escherichia coli K10; Holler E; The kinetics of binding of Phe-tRNAPhe to phenylalanyl-tRNA synthetase were investigated by stopped-flow techniques employing 2-(p-toluidinyl)naphthalene-6-sulfonate as a reporter group . The kinetics were found to follow the concentration of Phe-tRNAPhe in terms of a saturation function . When added, tRNAPhe inhibited both the kinetics of association and the kinetics of dissociation . The kinetics of Phe-tRNAPhe binding have been analyzed to be a superposition of two reactions, the association to the phenylalanine-specific binding site and the association to the tRNA-specific binding site of the enzyme . The two modes are mutually exclusive . When tRNAPhe is added, the binding of Phe-tRNAPhe at the tRNA-specific site is suppressed by competitive inhibition . In binding to the tRNA-specific site, the unacylated tRNA affects the rates of association and dissociation of Phe-tRNAPhe binding at the Phe-specific site in terms of an antagonistic mechanism . The values of both rate constants are decreased depending on the degree of saturation of the enzyme with the unacylated tRNA before and after the association of Phe-tRNAPhe . A model is presented, and kinetic and equilibrium constants are determined.

Biochemistry, 1980 Apr 1, 19(7), 1392 - 6
Escherichia coli ribonucleic acid polymerase binding to the deoxyribonucleic acid of the echinoid Paracentrotus lividus: properties of the complexes and distribution of stable binding sites; Di Mauro E et al.; We describe the properties of the complexes that form between Escherichia coli RNA polymerase and Paracentrotus lividus DNA: dissociation kinetics, temperature dependence of the complex formation, resistance to heparin, and range of RNA polymerase-DNA weight/weight ratios that give rise to the stable binding events . The amount and distribution of the sites that form stable binding {class A sites as defined by Hinkle & Chamberlin {Hinkle, D., & Chamberlin, M . J . (1972) J . Mol . Biol . 70, 157}} with E . coli RNA polymerase were determined by the analysis of the dissociation of complexes formed by the enzyme on DNA fragments of various length . The P . lividus appears to form 3.1 X 10(5) stable (t1/2 greater than or equal to 15 min) complexes per haploid genome; the great majority of these complexes shows a short-range distribution (1000-2000 base pairs) . The observed attributes of the stable binding sites of P . lividus DNA for E . coli RNA polymerase (amount, distribution, and quantitative ability to start in vitro RNA chains) point to the conclusion that E . coli and sea urchin DNA are nearly indistinguishable by the criteria adopted . The behavior of the sea urchin stable binding sites for the E . coli enzyme is not consistent with the expected behavior of the in vivo promoters.

Mol Gen Genet, 1980 Apr, 178(1), 9 - 20
Replication origin of the Escherichia coli K-12 chromosome: the size and structure of the minimum DNA segment carrying the information for autonomous replication; Oka A et al.; A DNA fragment containing the replication origin of the Eschericia coli K-12 chromosome was inserted in two correlations at either the BamHI or SalI site of pBR322 DNA . All the resulting hybrid plasmids were found to replicate in both polA and polA+ cells, whereas pBR322 replicates only in polA+ cells . This characteristic provided a method for assaying the autonomously replicating ability (Ori function of the E . coli origin . In order to define the minimum DNA region (ori) that determines Ori function, deletions of various sizes were introduced from either side of the ori-containing segment in the hybrid plasmids by in vitro techniques, and the correlation between the Ori phenotype and nucleotide sequence of the deletion derivatives was analyzed . It was found that the left end of ori is between positions 23 and 35, and the right end is either position 266 or 267 in our nucleotide coordinate (Sugimoto et al., 1979) . Therefore, ori is present within a region of minimum 232 base pairs and maximum 245 base pairs in length . The Ori+ and Ori- phenotypes were clearly resolved at both sides of these boundaries by the above assay procedure . To obtain information about the effect of mutations in the internal region of the defined ori stretch, short sequences were inserted or deleted in vitro in the vicinity of several restriction sites within ori on the hybrid plasmids . Most of these plasmids carrying modified sequences showed Ori- phenotype, suggesting that most parts of the ori stretch play important roles in Ori function.

Mol Gen Genet, 1980 Apr, 178(1), 51 - 8
Restriction in vivo . V . Introduction of SOS functions in Escherichia coli by restricted T4 phage DNA, and alleviation of restriction by SOS functions; Dharmalingam K et al.; Degradation products of restricted T4 DNA induced filamentation, mutagenesis, and to a lesser extent, synthesis of recA protein in wild type cells but not in recA, lexA or recBC mutants of Escherichia coli . We conclude that the structural damage to the DNA caused by restriction cleavage and exonuclease V degradation can induce SOS functions . Degradation of restricted nonglycosylated T4 DNA by exonuclease V delayed cell division and induced filament formation and mutagenesis in lexA+ but not in lexA- cells . Delay of cell division was also dependent upon recA and recBC functions . Such degradation of DNA also dramatically increased mutagenesis in tif- Sfi- cells at 42 degrees . The synthesis of recA protein continued in the restricting host after infection by the monglucosylated T4 phage, but enhanced synthesis is not induced to the extent seen in SOS induced tif- cells grown at 42 degrees . We also found that restriction of nonglycosylated T4 was alleviated in UV irradiated cells . The UV induced alleviation of rgl and rK restriction depended upon post irradiation protein synthesis and was not observed in recA, lexA or recBC mutants.

Immunology, 1980 Apr, 39(4), 535 - 9
Endotoxin-induced appearance of peroxidase-positive cells in the white pulp of the mouse spleen; Jasani B et al.; Endotoxin (1-10 microgram intravenously) increased the number of strongly peroxidase-positive cells in the white pulp of the mouse spleen, demonstrable by the Graham-Karnovsky technique . The increase was greatest after 10 h, the cells being found most frequently around the central vessels of the white pulp . The appearance of such cells at this critical immunological site may relate to the known adjuvant activity of endotoxin in promoting immune responses against protein antigens.

Gene, 1980 Apr, 9(1-2), 1 - 12
Secondary structure of mRNA and efficiency of translation initiation; Iserentant D et al.; A series of recombinant plasmids, containing the cro gene of phage lambda, exhibit strikingly different levels of expression depending apparently only on the nucleotide sequence of the untranslated 5' mRNA (Roberts et al., 1979) . We postulate that initiation of translation involves interaction between an activated 30S ribosomal subunit and the 5'-terminal region of a messenger RNA already folded in a specific secondary structure . The observed variation in cro synthesis can then adequately be explained by secondary structure models which were derived for the different mRNAs . To maximize expression, it appears necessary that the initiation codon and, although less important, the ribosome interaction site are accessible.

Eur J Biochem, 1980 Apr, 105(2), 297 - 306
Precursor forms of the subunits of nitrate reductase in chlA and chlB mutants of Escherichia coli K12; Giordano G et al.; The synthesis of nitrate reductase by a parental Escherichia coli K12 strain and its isogenic chlA and chlB mutants has been analyzed by protein double labelling with L-{4,5-3H}leucine and sulphur-35 and by immunoprecipitation using specific antiserum . The chlA and chlB mutants although defective in nitrate reductase activity retain the ability to synthesise the different polypeptides that are normally required for functional enzyme activity . In addition the data shows the following . 1 . These polypeptides are present in unequal quantities in the membrane and in the cytoplasm of the cells . The chlB mutant synthesizes three times more nitrate reductase than the chlA mutant . 2 . The subunit composition of the membrane-bound nitrate reductase present in the two mutants is different . 3 . Membrane preparations from the chlB mutant contain the three subunits alpha, beta, gamma in a ratio which is similar to the wild type . 4 . In the chlA mutant the two subunits beta and gamma are missing and the level of alpha subunit is very low . In the same membrane a 48,000-Mr subunit (polypeptide beta') precipitable by nitrate reductase antiserum has been found . The chlA and chlB mutants accumulate the three subunits alpha, beta and gamma in different proportion and concentrations in the cytoplasm unlike the parental strain . 5 . The cytoplasm from the chlA mutant also contains the beta' polypeptide found in the membrane fraction of this mutant and in addition contain another polypeptide designated alpha' of molecular weight 105,000 which is precipitated by the nitrate reductase antiserum . The formation of particulate active nitrate reductase can be achieved by mixing the supernatant fractions of the chlA and chlB mutants (complementation) and procedes by two distinct but mutually dependent stages . Following reconstitution of activity the two peptides alpha' and beta' present in the supernatant fraction of the chlA mutant, disappear . Analysis of the immunoprecipitate polypeptides present in both the soluble and particulate nitrate reductase protein after reconstitution suggests that these polypeptides are precursors of the alpha and beta subunits following a process that remains to be elucidated.

Cell Differ, 1980 Apr, 9(2), 83 - 93
Variations in accessibility of DNA during traumatic regeneration by Owenia fusiformis (polychaete annelid); Fontes M et al.; One of the earliest events observed in the 'dedifferentiation phase' of traumatic regeneration is an in vivo increase in transcription . In order to see whether that increase corresponds to a variation at the level of genetic material, we prepared chromatin from normal and regenerating animals (12 h after amputation) for transcription in vitro by E . coli RNA polymerase . The template activity of regenerating chromatin was 2.1-fold higher than normal under standard conditions and showed an altered response to variation of the ionic strength of the medium . The accessibility of DNA in the chromatin was tested using mild digestion by DNAase II . Almost twice as much DNA was solubilised from regenerating chromatin as from normal chromatin . These data were correlated with morphological changes (decondensation) observed by electron microscopy.

Can J Biochem, 1980 Apr, 58(4), 309 - 18
The kinetic properties of phosphoenolpyruvate carboxykinase of Escherichia coli; Krebs A et al.; Initial rate kinetic studies on phosphoenolpyruvate carboxykinase of Escherichia coli are consistent with either of two sequential kinetic mechanisms: rapid equilibrium random, or partially ordered . However, the kinetics of isotope exchange at chemical equilibrium allows clear discrimination in favor of a random mechanism containing a preferred pathway of substrate addition and product release . All plots of exchange rates vs . reactant concentrations leveled off at constant rates at saturating levels of substrates; since complete inhibition of any exchange was not observed, a compulsory sequence may be eliminated . High concentrations of phosphoenolpyruvate and (or) ATP repressed the oxaloacetate in equilibrium bicarbonate exchange, however, indicating that the latter pair of substrates add most favorably to the free enzyme . Exchange rates between various substrate-product pairs were not identical, ruling out a formally rapid equilibrium random mechanism with rate-limiting interconversion of the central complex . A comparison of the relative rates of the overall reaction and the ATP-dependent oxaloacetate in equilibrium bicarbonate exchange showed the latter to be much faster than net formation of oxaloacetate . The requirement for ATP in promoting this exchange may be rationalized in terms of substrate synergism, with occupation of the ATP binding site a requisite for its catalysis.

Biokhimiia, 1980 Apr, 45(4), 652 - 60
{Interactions of ribosomes with an unsaturated fatty acid}; Sorokina AD et al.; The interaction of bacterial and plant ribosomes with an unsaturated fatty acid and the effect of the latter on the physico-chemical properties of the ribosomes were studied . The ability of E . coli ribosomes and ribosomes from pea seedlings chloroplasts and cytoplasm to form complexes during interaction with the oleic acid were revealed . Evidence for heterogeneity of the bacterial ribosomal fraction, which manifests itself in the fact fat not all ribosomes within a single population are capable to interaction with the oleic acid have been obtained . Changes in the sedimentation and morphological properties typical for different types of ribosomes were observed . The interaction of bacterial ribosomes with the oleic acid and a subsequent removal of the oleic acid with Triton X-100 resulted in an increase of the sedimentation coefficient of the particles from 70S up to 175S and a considerable compactization of ribosomal particles . No such changes were observed in the case of plant ribosomes.

Biokhimiia, 1980 Apr, 45(4), 579 - 93
{Ribosomal proteins of Escherichia coli . Some features of the primary and three-dimensional structure}; Alakhov IuB; Some properties of E . coli ribisomal proteins, e . g . molecular weights, isoelectric points, amino acid composition, are reviewed . The three-dimensional structure of the proteins in solution has been studied and the difficulties and discrepancies arising from interpretation of the results obtained have been revealed . The peculiarities of the amino acid sequences typical of the majority of the proteins or the amino acid sequences presenting unique features are interpreted in terms of the primary structure of some ribosomal proteins . The primary structure of the proteins determined with the use of interesting methodological procedures is discussed.

Am J Epidemiol, 1980 Apr, 111(4), 432 - 6
Heat-labile enterotoxigenic Escherichia coli induced diarrhea aboard a Miami-based cruise ship; Lumish RM et al.; Beginning in late December, 1975, almost one-third of the passengers on two successive cruises of a Miami-based cruise ship noted the onset of diarrheal illness while on board . A single serotype of Escherichia coli that produced heat-labile enterotoxin without producing heat-stable enterotoxin was recovered from the stool of most ill passengers cultured . Epidemiological investigation could not specifically define the mode of spread . The clinical picture presented was similar to the illness caused by enterotoxigenic E . coli that produce only heat-stable enterotoxin or that produce heat-stable and heat-labile enterotoxins.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 2173 - 7
Isolation of the centromere-linked CDC10 gene by complementation in yeast; Clarke L et al.; A hybrid plasmid colony bank was constructed in Escherichia coli using the E . coli-Saccharomyces cerevisiae shuttle vector pLC544 and randomly sheared segments of yeast DNA . By transformation with a hybrid plasmid DNA pool from this collection and complementation of a temperature-sensitive cdc10 mutation in yeast, a plasmid was isolated that carries 8 kilobase pairs of DNA around the chromosome III centromere-linked CDC10 locus . This DNA segment overlaps a larger region of DNA (40 kilobase pairs) previously identified to be around the LEU2 locus on chromosome III {Chinault, A.C . & Carbon, J . (1979) Gene 5, 111-126} and physically establishes the directionality of the cloned DNA sequences with respect to the genetic map and the centromere . In the leu2-cdc10 interval, the relationship between physical distance on the DNA and genetic distance as measured by recombinational frequencies is about 3 kilobase pairs per centimorgan.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 2005 - 9
Amino-terminal sequence and processing of the precursor of the leucine-specific binding protein, and evidence for conformational differences between the precursor and the mature form; Oxender DL et al.; A 2.1-kilobase Bgl II DNA fragment from Escherichia coli containing livK, the gene coding for the leucine-specific binding protein, has been cloned into the BamHI site of the plasmid vector pBR322 . The DNA sequence of segments of the resulting plasmid, pOX7, established the location of the livK gene and the direction of its transcription . In vitro protein synthesis directed by pOX7DNA yielded the Mr 42,000 precursor of the leucine-specific binding protein and a small amount of the Mr 39,000 mature protein . Continued incubation of the in vitro reaction mixture after DNase and RNase treatment resulted in additional processing . The DNA sequence of the beginning of livK suggested that 23 additional amino acid residues are present as an extension of the NH2 terminus of the mature protein . Amino acid sequence analysis established that the precursor has the predicted 23-residue extension . Proteolytic digestion studies with the precursor and mature forms of the leucine-specific binding protein indicate that there are conformational differences between the two . This suggests a possible role for the signal sequence in determining the conformation of the binding protein precursor that is recognized by the membrane.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1932 - 6
The lexA gene product represses its own promoter; Brent R et al.; The products of the lexA and recA genes of Escherichia coli regulate the cellular response to DNA damage (the SOS response) . Here we describe the cloning of the wild-type lexA gene and the identification of its 24,000-dalton protein product . We also describe construction, by recombination in vitro, of a phage that bears the lexA promoter fused to the lacZ gene . Experiments with this fusion phage and with multicopy plasmids that carry the lexA gene showed that the lexA gene product represses of its own promoter . This repression occurs even if the cell has no recA gene, showing that the lexA protein need not be complexed to the recA protein for activity . Moreover, the presence of multicopy plasmids that carry the lexA gene blocks expression of all SOS responses tested . This presumably results from two effects: (i) repression of the recA gene, the product of which is required to activate many of these responses; and (ii) direct repression of other functions involved in the SOS response.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1823 - 7
Nucleotide sequence of ilvGEDA operon attenuator region of Escherichia coli; Nargang FE et al.; The nucleotide sequence of the DNA thought to contain the control region for the ilvGEDA operon in Escherichia coli has been determined by the Maxam-Gilbert procedure . The sequence includes a region that, upon transcription, would yield a leader transcript specifying a peptide 32 residues long . This putative peptide would contain four leucine, five isoleucine, and six valine residues . A model is proposed that correlates the multivalent control of the ilvGEDA operon with the extent to which this leader transcript is translated . In vitro transcription experiments yielded a transcript of about 183 nucelotides, compatible with the predictions of the model.

J Neurosurg, 1980 Apr, 52(4), 547 - 52
Compartmentalization of the cerebral ventricles as a sequela of neonatal meningitis; Kalsbeck JE et al.; Thirteen infants with compartmentalization of the lateral ventricles diagnosed by air encephalography, computerized tomography, or autopsy are reported . In each case, the body of one or both lateral ventricles was completely divided by a membrane posterior to the foramen of Monro . Recognition of this entity is important from both therapeutic and prognostic standpoints.

J Clin Microbiol, 1980 Apr, 11(4), 343 - 8
Enterotoxigenic Escherichia coli in central Canada; Brunton J et al.; During epidemiological studies carried out in urban and rural areas of the midwestern Canadian province of Manitoba, we cultured enterotoxigenic Escherichia coli (ETEC) from 16 (1.7%) of 945 diarrheal stools and 4 (0.3%) of 1,282 normal stools . ETEC was found in not more than 2.3% of diarrheal stools obtained from any population during any season . Diarrhea associated with ETEC persisted for a mean of 9 days . Two children were dehydrated and required intravenous fluid therapy, and one adult suffered a cholera-like syndrome . Half of the children required hospitalization for management of their diarrhea . Two adults and two children who harbored ETEC were completely asymptomatic . The pattern of toxin production correlated with serotype and the serotypes encountered were (with a few exceptions) similar to those found in other areas . We conclude that ETEC is an uncommon cause of diarrhea, both in rural and urban areas of central Canada . However, the possibility that ETEC might cause severe sporadic cases or epidemics of gastroenteritis remains.

J Bacteriol, 1980 Apr, 142(1), 347 - 9
uhp-directed, glucose 6-phosphate membrane receptor in Escherichia coli; Goldenbaum PE et al.; Membrane vesicles were characterized for their ability to specifically bind {14C}glucose 6-phosphate . Membranes prepared from a strain carrying a ColE1 uhp hybrid plasmid showed significantly enhanced glucose 6-phosphate binding . It is hypothesized that glucose 6-phosphate binding to these membranes is due to a uhpR-directed, membrane-bound receptor which functions in regulation of the inducible uhpT gene product: the hexose phosphate permease.

J Bacteriol, 1980 Apr, 142(1), 335 - 8
Nitrous acid damage to duplex deoxyribonucleic acid: distinction between deamination of cytosine residues and a novel mutational lesion; Frankel AD et al.; The rate of nitrous acid deamination of labeled cytosine residues in native Escherichia coli deoxyribonucleic acid was monitored in vitro by release of acid-soluble counts after treatment with uracil deoxyribonucleic acid glycosylase . The reaction exhibited a lag and was not stimulate by several agents previously shown to enhance base substitution mutagenesis during nitrous acid treatment of duplex deoxyribonucleic acid . We conclude that a significant proportion of nitrous acid induced mutagenic lesions are novel lesions and not cytosine deaminations.

J Bacteriol, 1980 Apr, 142(1), 319 - 21
The recA+ gene product is more important than catalase and superoxide dismutase in protecting Escherichia coli against hydrogen peroxide toxicity; Carlsson J et al.; Various deoxyribonucleic acid repair-deficient strains of Escherichia coli K-12 were exposed to hydrogen peroxide under anaerobic conling of the strains was determined . The level of catalase, peroxidase, and superoxide dismutase in cell-free extracts of the strains as well as the capacity of intact cells to decompose hydrogen peroxide were assayed, recA strains were more rapidly killed than other strains with deoxyribonucleic acid repair deficiencies . There was no correlation between the killing rate of the strains and the capacity of intact cells to decompose hydrogen peroxide or the level of catalase and superoxide dismutase in cell-free extracts . The level of peroxidase in cell-free extract was too low to be determined.

J Bacteriol, 1980 Apr, 142(1), 285 - 94
Outer membrane of Escherichia coli: properties of the F sex factor traT protein which is involved in surface exclusion; Manning PA et al.; The traT protein (TraTp) of the F sex factor is the product of one of the two genes involved in surface exclusion . Several detergents were examined under different conditions in order to determine their ability to solubilize TraTp from membrane vesicles . These experiments showed that TraTp behaved similar to a number of peptidoglycan-associated outer membrane proteins and that it existed in multimeric aggregates within the membrane . However, unlike other major outer membrane proteins, the amount of TraTp incorporated into the membrane was not affected by lipopolysaccharide-deficient mutants, even when mutants totally lacking the neutral sugars in their lipopolysaccharide backbone were used . TraTp wqs also examined by two-dimensional gel electrophoresis, where it ran as a discrete spot with a very basic isoelectric point . By coupling cyanogen bromide-activated dextran onto whole cells and by labeling whole cells with 125I (via lactoperoxidase), it was shown that TraTp was exposed on the cell surface . TraTp in a membrane environment was also insensitive to proteolytic attack by trypsin.

J Bacteriol, 1980 Apr, 142(1), 185 - 90
Position effect on expression of dsd genes cloned onto multicopy plasmids; Carothers AM et al.; In the D-serine deaminase system of Escherichia coli, which is regulated by positive control, we have fouand a complete lack of trans activation in vivo with multicopy dsd hybrid plasmids . A PLASmid carrying the regulatory gene, dsdC+, did not promote expression of chromosomal dsdCO+A+ loci, nor did a chromosomal dsdC+ gene promote expression of plasmid-borne dsdC delta O+A+ (dsd regulatory gene negative) restriction fragments . However, hybrid plasmids that comprise the entire dsd system (dsdC+O+A+) are highly inducible for the enzyme . These dsd hybrid plasmid deoxyribonucleic acids functioned well as templates in the in vitro coupled transcription-translation system . In vitro-synthesized dsdC+ protein promoted expression of the dsdA+ operation efficiently . Exogenously purified dsdC+ protein also activated expression of several dsdC delta O+A+ plasmid deoxyribonucleic acid templates in vitro . An explanation that reconciles these results with previous dominance studies is presented.

J Bacteriol, 1980 Apr, 142(1), 162 - 8
Penetration of colicin M into cells of Escherichia coli; Braun V et al.; A new class of colicin M-tolerant mutants of Escherichia coli K-12 was isolated . The mutants exhibited an unusually high tolerance in that they were unaffected by colicin titers of 10(6) . The tolerance was confined to colicin M . It was mapped at a locus called tolM, which is close to rpsL . The following gene order was determined: aroE, tolM, rpsL, cysG . The tolerance could be caused by a defect in the uptake of colicin M or by a mutation at the site of action . Insensitive tonA and tonB mutants became sensitive to colicin M upon treatment by osmotic shock, whereas the tolM mutants remained insensitive . Trypsin rescue experiments showed that the tonB-dependent uptake of colicin M required energy like the other tonB-related transport processes . When bound to energy-depleted cells, colicin M prevented adsorption of phage T5 . The receptor became accessible to the phage when the cells were energized, except in tonB mutants . These data suggest that the function controlled by the tonB gene is required for the translocation of colicin M from its initial binding site at the tonA-coded receptor protein to the target.

J Bacteriol, 1980 Apr, 142(1), 120 - 30
Genetic locus, distant from ptsM, affecting enzyme IIA/IIB function in Escherichia coli K-12; Roehl RA et al.; Most strains of Escherichia coli K-12 are unable to use the enzyme IIA/IIB (enzyme IIMan) complex of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) in anaerobic growth and therefore cannot utilize glucosamine anaerobically . Introduction into these strains of a ptsG mutation, which eliminates activity of the enzyme IIIGlc/IIB' complex of the PTS, resulted in inability to grow anaerobically on glucose and mannose . Derivative strains able to grow anaerobically on glucosamine had mutations at a locus close to man, the gene coding for phosphomannose isomerase, and had higher enzyme IIA/IIB activities during anaerobic growth than did the parental strain . These results establish a locus affecting function of enzyme IIA/IIB that maps distant from ptsM, the probable structural gene for enzyme IIB.

J Am Vet Med Assoc, 1980 Apr 1, 176(7), 619 - 22
Evaluation of concentrated solutions of guaifenesin for equine anesthesia; Grandy JL et al.; The pH, osmolality, stability, and bacteriostatic characteristics of 5%, 10%, and 15% solutions of guaifenesin were studied . In vitro and in vivo experiments were done to determine the hemolytic potential of the more concentrated solutions on equine blood, as compared with the recommended 5% solution . The primary objective was to determine whether more concentrated solutions could be used clinically . The secondary objective was to determine the optimal diluent (water, 0.9% saline, or 5% dextrose) . It was concluded that a 10% solution of guaifenesin made in sterile distilled water was most suitable for clinical equine anesthesia . Such a preparation has reasonable storage qualities and does not induce clinically significant hemolysis.

Eur J Biochem, 1980 Apr, 105(3), 531 - 8
Tyrosine residues in the C-terminal domain of the elongation factor G are essential for its interaction with the ribosome; Alakhov YB et al.; Chemical modification of the elongation factor G (EF-G) with tetranitromethane and iodine has been studied . It has been shown by spectrophotometric titration that EF-G contains two exposed tyrosine residues, one of which has an unusually low pK value for a phenol hydroxyl group at pH 8.5 . Modification of one tyrosine residue with either tetranitromethane or iodine results in a 70--80% loss of EF-G activity in all ribosome-dependent reactions . Modification of three or four residues inhibits 90--100% of activity . Binding of EF-G with the 70-S ribosome and 50-S subunit is equally effective for protection of tyrosine residues against modification . The rate of EF-G modification with tetranitromethane is considerably higher in the presence of guanyl nucleotides than for free EF-G . The modified residues are located in the C-terminal domain of EF-G and are presumably contained in one of the sites of EF-G interaction with the ribosome.

Radiology, 1980 Apr, 135(1), 15 - 22
Transhepatic cholangiography: complicatons and use patterns of the fine-needle technique: a multi-institutional survey; Harbin WP et al.; A multi-institutional survey of complications and use patterns of fine-needle transhepatic cholangiography (FNTC) was conducted, and the results were compared with those of transhepatic cholangiography using a large, sheathed needle and endoscopic retrograde cholangiopancreatography . Data were based on 2,006 procedures, including 293 from the authors' institution . The overall incidence of serious complications with FNTC was 3.4% (sepsis 1.40%, bile leakage 1.45%, intraperitoneal hemorrhage 0.35%, death 0.20%) . The overall success rate was 97.8%; it was 99% when 12-14 needle passes were made, compared with only 95.5% when no more than 6 were made . It is concluded that 6 passes are not enough to exclude obstruction . One third of the patients with bile leakage had inadvertent puncture of the extrahepatic biliary tract . The pathogenesis of sepsis following FNTC is discussed and related to the author's recommendation of routine prior administration of ampicillin and gentamicin.

J Pediatr, 1980 Apr, 96(4), 757 - 61
Clinical pharmacology of two chloramphenicol preparations in children: sodium succinate (iv) and palmitate (oral) esters; Pickering LK et al.; The clinical pharmacology of chloramphenicol was evaluated in 14 children with serious bacterial infections . The children received chloramphenicol sodium succinate intravenously for five to six days at which time orally administered chloramphenicol palmitate was substituted for an additional five to six days of therapy . The mean peak serum chloramphenicol concentration when given iv (28.2 +/- 5.1 micrograms/ml) occurred within one hour after the termination of the 60-minute iv infusion and when given orally (19.3 +/- 2.6 micrograms/ml) occurred two to three hours after ingestion . Differences in serum levels of chloramphenicol after iv compared to oral administration of the same dose could be demonstrated at various time points studied during the dose-response curves; however, the areas under the chloramphenicol curve were not significantly different after iv (140 +/- 116 micrograms/ml/hour) versus oral (95 +/- 26 micrograms/ml/hour) administration . In seven patients who had concomitant serum and CSF chloramphenicol levels determined, a CSF to serum ratio of 23 to 85% occurred . The CSF levels (5.5 to 13 micrograms/ml) were not directly proportional to serum levels . All patients recovered from their infection and no side effects from chloramphenicol were encountered . Administration of chloramphenicol orally in the palmitate form produces serum concentrations and areas under the disappearance curve similar to those achieved after iv administration of the same dose, indicating that the oral route is an effective method of achieving therapeutic concentrations of chloramphenicol in serum.

Gastroenterology, 1980 Apr, 78(4), 782 - 90
Fluorescent PAS-reaction study of the epithelium of normal rabbit ileum and after challenge with enterotoxigenic Escherichia coli; Khavkin TN et al.; Fluorescent periodic acid-Schiff reaction (FPR) was used in the study of the normal rabbit ileal epithelium and its changes after injection of living cultures or enterotoxins of enterotoxigenic Escherichia coli . This reaction, with the use of auramine OO-SO2 complex as a Schiff-type reagent, demonstrates gut epithelium periodate-reactive mucosubstances more distinctly and brightly than does the common periodic acid-Schiff (PAS) reaction . It permitted the quantitative assessment of polysaccharide content in the gut sections by microfluorimetry, and examined extensively the mucosal structures, brush border, and mucous cells which participate in the interaction with enteropathogens . Fluorescent periodic acid-Schiff reaction showed that noninvasive enterotoxigenic E . coli O148:H28 B7A organisms caused restricted damage to the intestinal epithelium brush border . Invasive enterotoxigenic E . Coli O26:K60:H11 N3 organisms penetrated the epithelium and caused extensive brush border lesions and mucous cell hyperproduction . Importance of FPR in the complex morphologic analysis of enteric infections, pathogenesis of escherichoses under study, and some aspects of the intestinal epithelium histology are discussed.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1787 - 90
Reconstitution of a deoxyribonuclease I-sensitive structure on active genes; Gazit B et al.; Chicken erythrocyte nuclei have been labeled in the active regions of the chromosome by using the nick translation reaction . In this procedure, accessible areas of the genome are preferentially nicked by the action of pancreatic DNase I and subsequently labeled by using DNA polymerase I from Escherichia coli . These nuclei were employed as a substrate for studying the factors responsible for maintaining the special chromatin conformation of the overall population of active genes . Treatment of nuclei with 0.35 M NaCl resulted in the loss of DNase I sensitivity in the active genes, but this sensitivity could be restored when nuclei were reconstituted with the NaCl eluate . Further purification of the released factors revealed that the HMG (high-mobility group) proteins HMG-14 and HMG-17 are involved in maintaining the conformation of the active regions . These factors are not tissue specific and seem to be involved in the chromosomal structure of most of the active genes.

J Gen Microbiol, 1980 Apr, 117(2), 437 - 47
Preparation and quantitative determination of antibodies against major outer mambranes proteins of Escherichia coli O26 K60; Hofstra H et al.; Antisera against isolated outer membrane (OM) proteins I and II of Escherichia coli O26 K60 were elicited in rabbits . Antisera obtained after intramuscular administration with Freund's complete adjuvant showed high titres of specific antibodies . Intravenous administration of the same preparations yielded a considerable antibody response against bacterial lipopolysaccharide, a minor contaminant of the protein preparations . Antibody titres against OM proteins I and II, lipopolysaccharide and murein-lipoprotein were determined by the enzyme-linked immunosorbent assay (ELISA) in these sera, and in antisera elicited against whole formaldehyde-fixed bacteria or isolated OM . Comparison of ELISA with single radial immunodiffusion and interfacial immunoprecipitation tests revealed that ELISA was not only the most uniformly applicable, but also the most specific and the most convenient method . In double diffusion tests no cross-reactivity between proteins I and II was seen . Antibodies against proteins I and II, lipopolysaccharide and lipoprotein could be specifically absorbed from the sera with the appropriate antigen preparations . Absorption experiments with intact E . coli O26 K60, Tris/EDTA-sheared bacteria and isolated OM revealed that antibodies against protein I were hardly absorbed at all probably because the antibody, evoked against denatured protein I, did not react with the protein in its native configuration . Antibodies against protein II and lipoprotein were absorbed by intact as well as by sheared bacteria, but to a much greater extent by isolated OM, which indicates that these OM components are accessible from the outside, but that they are situated relatively deep in the OM structure.

Biochemistry, 1980 Apr 1, 19(7), 1425 - 33
Group fractionation and determination of the number of ribosomal subunit proteins from Drosophila melanogaster embryos; Chooi WY et al.; Proteins were extracted from ribosomes and (for the first time) from ribosomal subunits of Drosophila melanogaster embryos . The ribosomal proteins were analyzed by two-dimensional polyacrylamide gel electrophoresis . The electrophoretograms displayed 78 spots for the 80S monomers, 35 spots for the 60S subunits, and 31 spots for the 40S subunits . On the basis of present information, we propose what we believe to be a reliable and convenient nomenclature for the proteins of the ribosomes and each of the subunits . A pair of acidic proteins from D . melanogaster appears to be very similar in electrophoretic mobility to the acidic proteins L7/L12 from Escherichia coli and L40/L41 from rat liver . The electrophoretogram of proteins from embryonic ribosomes shows both qualitative and quantitative differences from those of larvae, pupae, and adults previously reported by others . The proteins of the 40S subunit range in molecular weight from approximately 10,000 to 50,000, and those from the 60S subunit range from approximately 11,000 to 50,000.

Aust N Z J Surg, 1980 Apr, 50(2), 141 - 6
The management of haemorrhagic complications of pseudocysts and abscesses of the pancreas; McMahon MJ et al.; We have reviewed the literature relating to experience of haemorrhage associated with pancreatic pseudocysts and abscesses in an attempt to evaluate different types of management . A further case, where extensive pancreatic resection successfully halted bleeding which followed drainage of a pancreatic abscess, is described to illustrate some of the principles of management.

J Bacteriol, 1980 Apr, 142(1), 52 - 9
Autolysis of Escherichia coli; Leduc M et al.; Autolysis of unwashed exponential-phase Escherichia coli cells was efficiently promoted by first submitting them to a quick downshock with distilled water before an upshock with 0.5 M sodium acetate, pH 6.5 . The association of these two osmotic shocks had a remarkable synergistic effect and led to significant decreases in turbidity and viability . Different factors influencing the rate of cell lysis were examined . A close correlation was established between autolysis and the degradation of peptidoglycan . Both phenomena were induced by the same shock treatment, followed similar kinetics, and were efficiently blocked by addition of divalent cations . Cell lysis was also inducible by a shock treatment with 10(-3) M ethylenediaminetetraacetic acid or ethylene glycol-bis(beta-aminoethyl ether)-N,N-tetraacetic acid and blocked by the addition of divalent cations.

Mol Gen Genet, 1980 Apr, 178(1), 165 - 72
Transfer-deficient cointegrates of Flac and lambda prophage; McIntire S et al.; Twelve transfer-deficient mutants of the plasmid Flac were obtained by insertion of prophage lambda into secondary attachment sites within the transfer region . Insertions into eight different tra genes were identified . These mutations were strongly polar on expression of tra genes previously mapped "downstream", and thus confirmed that the genes traA through traD form a single operon . However, some continued expression of traI suggested that this was transcribed in part from a promoter located between traD and traI, and in part from the transfer operon promoter . One insertion early in the transfer operon produced a plasmid-specific tra mutation not complemented by R100-1 or R1-19: this insertion was into a new gene (traY), located before traA as the first member of the transfer operon . Partial tra deletion mutants were obtained as 42 degrees C--survivors from several of the Flac tra::ED lambda 4 plasmids, and their properties are described.

Infect Immun, 1980 Apr, 28(1), 286 - 9
Isolation of enterochelin from the peritoneal washings of guinea pigs lethally infected with Escherichia coli; Griffiths E et al.; Escherichia coli secretes enterochelin while infecting normal guinea pigs . Since production of enterochelin is a well-characterized response to an iron-restricted environment, this work establishes that host iron-binding proteins do indeed influence the metabolism of the invading organism.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 2153 - 7
Evidence of RNA in D loops of intracellular lambda DNA; Chattoraj DK et al.; If lambda DNA replication is blocked by mutation in any one of several genes essential for replication, intracellular lambda DNA often shows short three-stranded regions called D loops . In this report we show that one arm of a D loop is an RNA . DNA hybrid, whereas the remaining arm is made up of single-stranded DNA . The RNA can be partially removed by RNase A and totally removed by RNase H . Also, D loops do not appear if infections are made in cells treated with rifampin, a potent inhibitor of transcription by Escherichia coli RNA polymerase . Several genes associated with recombination, including the host recA gene, are not essential for D-loop formation.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1837 - 41
In vitro expression of Escherichia coli ribosomal protein genes: autogenous inhibition of translation; Yates JL et al.; Escherichia coli ribosomal protein L1 (0.5 micro M) was found to inhibit the synthesis of both proteins of the L11 operon, L11 and L1, but not the synthesis of other proteins directed by lambda rifd 18 DNA . Similarly, S4 (1 micro M) selectively inhibited the synthesis of three proteins of the alpha operon, S13, S11, and S4, directed by lambda spcI DNA or a restriction enzyme fragment obtained from this DNA . S8 (3.6 micro M) also showed preferential inhibitory effects on the synthesis of some proteins encoded in the spc operon, L24 and L5 (and probably S14 and S8), directed by lambda spcl DNA or a restriction enzyme fragment carrying the genes for these proteins . The inhibitory effect of L1 was observed only with L1 and not with other proteins examined, including S4 and S8 . Similarly, the effect of S4 was not observed with L1 or S8, and that of S8 was not seen with L1 or S4 . Inhibition was shown to take place at the level of translation rather than transcription . Thus, at least some ribosomal proteins (L1 S4, and S8) have the ability to cause selective translational inhibition of the synthesis of certain ribosomal proteins whose genes are in the same operon as their own . These results support the hypothesis that certain free ribosomal proteins not assembled into ribosomes act as "autogenous" feedback inhibitors to regulate the synthesis of ribosomal proteins.

J Gen Microbiol, 1980 Apr, 117(2), 419 - 22
Isolation and characterization of a mutant of Escherichia coli K12 synthesizing DNA polymerase I and endonuclease I constitutively; Ahmad SI et al.; A mutant of Escherichia coli K12, highly resistant to ultraviolet radiation, has been isolated . Preliminary tests show that this mutant is also resistant to mitomycin C, nalidixic acid, fluorouracil and thymineless death . The mutant strain apparently repairs its damaged DNA more efficiently than wild-type E . coli K12 strains and, to do so, constitutively produces 35 times more DNA polymerase I and 12 times more endonuclease I than the wild-type strain.

J Gen Microbiol, 1980 Apr, 117(2), 369 - 76
Amino-sugar transport systems of Escherichia coli K12; Jones-Mortimer MC et al.; Glucosamine, mannose and 2-deoxyglucose enter Escherichia coli by the phosphotransferase system coded for by the gene ptsM . The glucosamine- and mannose-negative, deoxyglucose-resistant phenotype of ptsM mutants can be suppressed by a mutation mapping near ptsG that allows constitutive expression of the glucose phosphotransferase coded for by the gene ptsG . N-Acetylglucosamine enters E . coli by two distinct phosphotransferase systems (White, 1970) . One of these is the PtsM system, the other is coded for by a gene which maps near the nagA,B genes at about min 15 on the E . coli chromosome . We propose that this gene be designated ptsN . Strains with either of these components of the phosphotransferase system will utilize N-acetylglucosamine as sole carbon source.

Mol Gen Genet, 1980 Apr, 178(1), 229 - 31
Unusual behaviour of SPO1 DNA with respect to restriction and modification enzymes recognizing the sequence 5'-G-G-C-C; Reeve JN et al.; SPO1 DNA contains only 5 cleavage sites for restriction enzymes which recognize and cleave the sequence 5'-G-G-C-C (HaeIII or BsuR) . Fragments of SPO1 DNA cloned in E . coli to substitute 5'-hydroxymethyluracil (HMU) by thymine (T) remain resistant to HaeIII indicating that this unexpectedly small number of cleavages by HaeIII is not correlated with the presence of HMU in the normal phage DNA . It was previously shown that SPO1 is neither subject to B . subtilis R restriction (Trautner et al., 1974) nor modification in vivo (Gunthert et al., 1975) . We now show that SPO1 DNA can however be restricted and modified in vitro.

Mol Gen Genet, 1980 Apr, 178(1), 179 - 83
Regulation of cyclic AMP of the ilvB-encoded biosynthetic acetohydroxy acid synthase in Escherichia coli K-12; Sutton A et al.; The biosynthetic acetohydroxy acid synthase activities of E . coli K 12 are encoded by three genetic loci namely, ilvB (acetohydroxy acid synthase I), ilvG (acetohydroxy acid synthase II) and ilvHI (acetohydroxy acid synthase III) . The previously reported involvement of cyclic AMP in the regulation of the biosynthetic acetohydroxy acid synthase isozymes in E . coli K-12 was found to be due to the effect of this nucleotide on the expression of ilvB . Cyclic AMP had no effect on acetohydroxy acid synthase activity in strains lacking wild-type ilvB activity but containing the remaining isozymes . Very little activity of acetohydroxy acid synthase coded for by ilvV was found when ppGpp and cyclic AMP were severely limited . Addition of cyclic AMP under these conditions increased ilvB expression 24-fold . The data suggest that in addition to multivalent repression and ppGpp, cyclic AMP plays a major role in the regulation of the ilvB biosynthetic operon.

Mol Gen Genet, 1980 Apr, 178(1), 155 - 64
Serine sensitivity of Escherichia coli K 12: partial characterization of a serine resistnat mutant that is extremely sensitive to 2-ketobutyrate; Danchin A et al.; E . coli wild type bacteria display sensitivity towards serine . A selection medium is described which allows selection of serine resistant mutants . One such mutant is described which presents pleiotropic alterations: it exhibits a thermosensitive growth pattern, alteration in the metabolism of the pppGpp and ppGpp nucleotides, cAMP intracellular level alteration, extreme sensitivity to 2-ketobutyric acid and a defect in the phosphotransferases permeation system . A conjecture explaining these apparently unrelated defects supposes that serine metabolism interferes via phosphoenol pyruvate with a cytoplasmic control of membrane activity (the mutant would be defective in the coupling between membrane and the protein responsible for its cytoplasmic control) and that 2-ketobutyrate is an effector of this activity.

Gene, 1980 Apr, 9(1-2), 69 - 85
Construction of new cloning vehicles with genes of the tryptophan operon of Escherichia coli as genetic markers; Enger-Valk BE et al.; In vitro recombination techniques were used to construct a series of new cloning vehicles with genes of the tryptophan (trp) operon of Escherichia coli as selective marker . To construct these plasmids we have made a restriction cleavage map of the trp operon for the enzymes AosI, AvaI, BglI, BglII, HindIII, HpaI, PvuII, SalI, SstI and XhoI . The constructed plasmids pHP39, pEP392, pEP3921 and pEP3923 are derived from the amplifiable plasmid pBR345 and carry two or more genes of the trp operon, which are controlled by the trp regulatory elements . Plasmid pEP3921 (7.0 kb) carries intact trpE and trpA genes and contains single BglII and SstI sites in trpE, a single HindIII site located between trpE and trpA, and single EcoRI, SalI and XhoI sites located outside the trp genes . Plasmid pEP121 (12 kb) is similar to pEP3921, but has an extra selective marker conferring bacterial resistance to ampicillin . Plasmid pEP3923 (7.4 kb) comprises intact trpB and trpA genes and single BglII, HindIII, EcoRI, SalI and XhoI sites . Plasmids pHP39 (9.8 kb) and pEP392 (9.8 kb) carry an intact trp operon and have two and one EcoRI site, respectively . Plasmid pHP3 (18 kb) carries an intact trp operon and markers for tetracycline and ampicillin resistance.

Gene, 1980 Apr, 9(1-2), 27 - 47
Plasmid vectors containing the tryptophan operon promoter suitable for efficient regulated expression of foreign genes; Hallewell RA et al.; Derivatives of plasmid pBR322 that are suitable for high-level expression of foreign genes have been constructed . The vectors contain the Escherichia coli tryptophan promoter, the trpE gene, and about 15% of the trpD gene . To obtain expression, foreign genes are fused to the trpD gene fragment . After induction of the trp operon with 3 beta-indolylacrylic acid, trp gene products increase at least 50-fold, to account for 55% of the newly synthesised protein and 30% of total protein in the cell.

Gene, 1980 Apr, 9(1-2), 171 - 4
Packaging of plasmid DNA containing the cohesive ends of coliphage lambda; Vollenweider HJ et al.; High yields of ColE1::Tn3-cos lambda plasmid genomes packaged in phage lambda virions (2.10(9) per ml) are produced by thermal induction of E . coli W3350 (lambda cI1857S7) lysogens carrying the plasmid DNA . The plasmid DNA is packaged in the linear form, with the right m' terminus of lambda being associated with the lambda tail.

Gene, 1980 Apr, 9(1-2), 157 - 69
Construction and properties of a ColE1::Tn3-cos lambda plasmid for determining RNA polymerase binding sites on ColE1 and Tn3; Vollenweider HJ et al.; To determine the location of the RNA polymerase binding sites on the ColE1 plasmid and Tn3 transposon, a special hybrid ColE1::Tn3-cos lambda molecule was constructed which contains the left arm of phage lambda DNA and the right lambda terminal fragment . This permits orienting ColE1 molecules, since the RNA polymerase binding pattern of these two lambda fragments are known to be distinct . ColE1 DNA contains seven binding sites and Tn3 binds three RNA polymerases, with some of the latter probably involved in the expression of the transposition of functions of this transposon . The relationship of these sites to the positions and orientations of known promoters, transcripts, genes and functions is discussed.

Gene, 1980 Apr, 9(1-2), 13 - 25
DNA rearrangements in a hybrid plasmid carrying the redB imm region of coliphage lambda; Bernardi F et al.; The hybrid plasmid consisting of pSC101 and the redB--N--imm region of phage lambda cI857 persists in cells grown at 30 degrees C but not in cells grown at 37 degrees C . In the latter case the plasmid was found to undergo several modifications . Restriction maps of these new plasmids indicate the following modifications: (1) the insertion of an IS1 element into gene N carried by the lambda fragment; (2) a mutation in the pL oL site of the same fragment, and (3) four large deletions (30 to 50% of the hybrid plasmid) which remove almost the entire lambda fragment . For the latter deletions, one endpoint seems to be fixed in the same restriction fragment of pSC101 while the other endpoint assumes four different positions on the lambda fragment; this might suggest a site-specific recombination event.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1867 - 71
Translocation of phospholipids from the inner to the outer membrane of Escherichia coli; Donohue-Rolfe AM et al.; The translocation of lipids from the inner to the outer membrane of Escherichia coli has been investigated by pulse-chase experiments . After a pulse with {2-3H}glycerol, the specific activity of the newly synthesized {3H}phosphatidylethanolamine was 5 times greater in the inner than in the outer membrane . During the chase, {3H}phosphatidylethanolamine was translocated to the outer membrane . At 37 degrees C, the half-life for translocation was 2.8 min . This rate was not influenced by alteration in the cellular growth rate at 37 degrees C . Altering the cellular growth temperature had a pronounced effect on the rate of phosphatidylethanolamine translocation . Energy inhibitors that deplete the protonmotive force markedly inhibited the translocation . Translocation was not affected by inhibitors of ATP, protein, or lipid synthesis . Phosphatidylglycerol and cardiolipin are transfocated very rapidly, with half-lives shorter than 30 sec.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1847 - 51
DNA gyrase action involves the introduction of transient double-strand breaks into DNA; Mizuuchi K et al.; DNA gyrase from Escherichia coli, in the presence of ATP, can both separate catenated DNA circles and unknot knotted DNA . Both these reactions require passage of a DNA segment through a transient double-strand break in DNA . Evidence that transient double-strand breaks are also involved in the supercoiling and relaxing activities of DNA gyrase is derived from experiments showing that the linking number of circular DNA is changed in steps of two . A mechanism is proposed for the action of the enzyme.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1768 - 72
Metabolite gene regulation of the L-arabinose operon in Escherichia coli with indoleacetic acid and other indole derivatives; Kline EL et al.; The ability of indole derivatives to facilitate RNA polymerase transcription of the L-arabinose operon in Escherichia coli was shown to require the catabolite activator protein (CAP) as well as the araC gene product . Adenosine 3',5'-monophosphate (cAMP) was not obligatory for araBAD transcription when the cells were grown in the presence of 1 mM indole-3-acetic acid or in the presence of indole-3-acetamide, indole-3-propionic acid, indole-3-butyric acid, or 5-hydroxyindole-3-acetic acid . However, these indole derivatives were unable to circumvent the cAMP requirement for the induction of the lactose and the maltose operons . Catabolic repression occurred when glucose was added to cells grown in the presence of L-arabinose and 1 mM indoleacetic acid or 1 mM cAMP . This effect was reversed at higher concentrations of indoleacetic acid or cAMP . The induction and the catabolite repression phenomena were quantitated by measuring the differential rate of synthesis of L-arabinose isomerase (the araA gene product) . These results indicated that indole metabolites from various living systems may regulate gene expression and may be involved in "metabolite gene regulation."

J Bacteriol, 1980 Apr, 142(1), 32 - 42
Structural and physiological studies of the Escherichia coli histidine operon inserted into plasmid vectors; Bruni CB et al.; A fragment of deoxyribonucleic acid 5,300 base paris long and containing the promoter-proximal portion of the histidine operon of Escherichia coli K-12, has been cloned in plasmid pBR313 (plasmids pCB2 and pCB3) . Restriction mapping, partial nucleotide sequencing, and studies on functional expression in vivo and on protein synthesis in minicells have shown that the fragment contains the regulatory region of the operon, the hisG, hisD genes, and part of the hisC gene . Another plasmid (pCB5) contained the hisG gene and part of the hisD gene . Expression of the hisG gene in the latter plasmid was under control of the tetracycline promoter of the pBR313 plasmid . The in vivo expression of the two groups of plasmids described above, as well as their effect on the expression of the histidine genes not carried by the plasmids but present on the host chromosome, has been studied . The presence of multiple copies of pCB2 or pCB3, but not of pCB5, prevented derepression of the chromosomal histidine operon . Possible interpretations of this phenomenon are discussed.

J Bacteriol, 1980 Apr, 142(1), 236 - 42
Inititation and termination of chromosome replication in Escherichia coli subjected to amino acid starvation; Marsh RC et al.; Initiation and termination of chromosome replication in an Escherichia coli auxotroph subjected to amino acid starvation were examined by following the incorporation of {3H}thymidine into the EcoRI restriction fragments of the chromosome . The pattern of incorporation observed upon restoration of the amino acid showed that starvation blocks the process of initiation prior to deoxyribonucleic acid synthesis within any significant portion of the EcoRI fragment which contains the origin of replication, oriC . In this experiment, no incorporation of {3H}thymidine into EcoRI fragments from the terminus of replication was observed, nor was it found when a dnaC initiation mutant was used to prevent incorporation at the origin which might have obscured labeling of terminus fragments . Thus amino acid starvation does not appear to block replication forks shortly before termination of replication . Attempted synchronization of replication initiation by including a period of thymine starvation subsequent to the amino acid starvation led to simultaneous incorporation of {3H}-thymidine into all EcoRI fragments within the 240-kilobase region that surrounds oriC . It is shown that the thymine starvation step allowed initiation and a variable, but limited, amount of replication to occur.

J Bacteriol, 1980 Apr, 142(1), 174 - 84
Physical mapping of the Escherichia coli D-serine deaminase region: contiguity of the dsd structural and regulatory genes; Carothers AM et al.; The genes dsdA, dsdO, and dsdC have been located on a 3.0-kilobase pair (kb) fragment of the Escherichia coli chromosome by a combination of techniques . The loci were first cloned onto lambda and various plasmid vectors . dsd hybrid plasmids were then digested with restriction enzymes, and the fragments were recloned to test for the presence of dsdC or dsdA . In one case, a 4.2-kb restriction fragment containing the dsdA operon was used to form a heteroduplex with a well-defined lambda dsd deoxyribonucleic acid . The results show that dsdA, dsdO, and at least 0.6 kb of dsdC are present on this piece of deoxyribonucleic acid . On the basis of the mapping analysis and the molecular weight of D-serine deaminase, 1.9 kb of the 4.2-kb fragment is accounted for by the three dsd loci . We conclude that dsdO and dsdC are contiguous . A detailed dsd restriction map is presented.

Genetika, 1980 Apr, 16(4), 733 - 5
{Formation of single-stranded breaks in newly-synthesized Escherichia coli DNA following treatment with bleomycin}; Dzhataev SA et al.; Changes in molecular weight of newly synthesized DNA was studied after bleomycin treatment of Escherichia coli cells . The treatment by this drug causes only the increase of dispersion in sedimentation profiles of daughter DNA strands in wild type cells . There are two alternative explanation of this fact . First, single-strand breakage does not occur in newly synthesized DNA, i.e . bleomycin-induced athyminic sites do not block cellular DNA polymerases . Second, it is possible to explain it by quick rejoining of given breaks by cell repair systems . The sedimentation profile of daughter DNA strands of recA mutant rules out the first possibility . Observed shift to low molecular weight fractions region strongly indicates the formation of single-strand breaks in newly synthesized DNA . Extensive daughter DNA degradation in xthA mutant supports the idea of the existence of very effective excision repair in the case of apyrimidinic sites . Thus, non-eliminated bleomycin-induced damage causes the formation of single-strand breaks in newly synthesized DNA strands . These breaks may be repaired in the course of recA-dependent post-replication repair.

Genetika, 1980 Apr, 16(4), 602 - 8
{Repair of bleomycin-induced damage to Escherichia coli DNA . I . Excision repair of apyrimidinic sites}; Dzhataev SA et al.; There are at least 4 endonucleolytic activities in Escherichia coli cells specific to apurinic and apyrimidinic sites in DNA . The main enzyme in the case of this type of DNA damage is believed to be an endonuclease VI responsible for 90% of total cell activity . Endonuclease VI is associated with exonuclease III which degrades DNA in 3'--5' direction . Our data indicate the absolute necessity of exonuclease III activity in repair of DNA containing apyrimidinic sites . It is possible that in the absence of endonuclease VI this type of DNA damage may be recognized by other endonucleases of E . coli--endonucleases III, V and especially endonuclease IV . During the postincubation of xthA mutant cells the normal molecular weight of DNA was not restored but even further DNA degradation was observed . DNA polymerase I takes part in DNA repair both in case of apyrimidinic sites and UV-induced pyrimidine dimers . Repair kinetics study showed partial molecular weight restoration in polA1 mutant . It is likely that in the absence of this enzyme some of its functions can be taken by other cell DNA polymerases.

Proc Natl Acad Sci U S A, 1980 Apr, 77(4), 1862 - 6
Multivalent translational control of transcription termination at attenuator of ilvGEDA operon of Escherichia coli K-12; Lawther RP et al.; The regulatory region for the ilvGEDA operon of Escherichia coli K-12 has been located and characterized . ilv leader RNA transcribed from this region is described, and the DNA sequence of the region is presented . This DNA sequence contains a transcription promoter, a region coding for a 32-amino-acid polypeptide containing multiple isoleucine, valine, and leucine codons, and a transcription termination site preceding the first structural gene . The mutually exclusive secondary structures of the leader RNA have been analyzed . On the basis of these data, a model for the multivalent attenuation of the ilvGEDA operon is proposed.

J Bacteriol, 1980 Apr, 142(1), 362 - 5
Regulation of membrane phospholipid syntheesis in Escherichia coli during temperature up-shift; Kainuma-Kuroda R et al.; The synthesis of membrane phospholipids and that of stable ribonucleic acid were inhibited during temperature up-shift of both rel+ and relA strains of Escherichia coli . The kinetics of the inhibition of the synthesis of both molecules were correlated with the kinetics of guanosine 5'-diphosphate-3'-diphosphate synthesis . Metabolic down-shift experiments gave similar results.

J Bacteriol, 1980 Apr, 142(1), 359 - 61
Gene rne affects the structure of the ribonucleic acid-processing enzyme ribonuclease E of Escherichia coli; Misra TK et al.; The activity, ribonuclease E, isolated from an rne mutant was irreversibly inactivated at lower temperatures than ribonuclease E isolated from a wild-type strain . This observation suggests that the mutation rne-3071 affects the structure of the ribonculease E enzyme.

J Bacteriol, 1980 Apr, 142(1), 325 - 6
Chromosomal location of a gene for chemical longevity of messenger ribonculeic acid in a temperature-sensitive mutant of Escherichia coli; Ono M et al.; Genetic analysis of a thermolabile mutation affecting alteration of messenger ribonculeic acid stability indicates that the gene ams maps close to pyrC gene (23 min) on the Escherichia coli chromosome and has a cotransduction frequency of 29.6% with pyrC gene . The probable gene order is pyrD-ams-pyrC-purB.

J Bacteriol, 1980 Apr, 142(1), 131 - 7
Glutamic acid codon suppressors derived from a unique species of glycine transfer ribonucleic acid; Murgola EJ et al.; In this paper we describe the successful isolation of glyT-derived GAA suppressors . A glyT+ strain containing glyV55, the gene for a GGA/G-reading, methane sulfonate and hydroxylamine . The cells were plated to select for reversal of auxotrophy due to a trpA(GAA211) mutation . With either mutagen, greater than 85% of the prototrophs obtained were due to suppressors of the trpA mutation . Approximately 12% of the ethyl methane sulfonate-induced and 37% of the hydroxylamine-induced suppressors were shown to be about 25% cotranscucible with metB, as is glyT . The transfer ribonucleic acid from four metB-linked suppressor strains (two from each mutagen) was examined by reversed-phase column (RPC-5) chromatography . In all four cases, the glycyl-transfer ribonucleic acid profile displayed an alteration of glyT transfer ribonucleic acid . All four suppressors responded to GAG in addition to GAA but did not suppress the known mutant codons of several other trpA mutants . Other properties are discussed, along with possible reasons for our success in obtaining these suppressors.

Eur J Biochem, 1980 Apr, 105(3), 481 - 7
Synthesis of 5' fragments of formylmethionine transfer ribonucleic acid and their reconstitution with a natural three-quarter molecule; Ohtsuka E et al.; An eicosanucleotide C--G--C--G--G--G--G--U--G--G--A--G--C--A--G--C--C--U--G--Gp corresponding to the bases 1--20 of the nascent sequence for the Escherichia coli tRNAfMet has been synthesized by the joining of the chemically synthesized oligonucleotides C--G--C--G, G--G--G--U--G--G and A--G--C--A--G--C--C--U--G--Gp using RNA ligase from T4-infected E . coli . The hexanucleotide and decanucleotide were phosphorylated with polynucleotide kinase and {gamma-32P}ATP prior to the joining reactions . The decanucleotide and eicosanucleotide were reconstituted respectively with the 3'-three-quarter molecule obtained by limited digestion with RNase T1 of the natural tRNAfMet from E . coli and the activity of the complex as a methionine acceptor was tested using purified methionyl-tRNA synthetase from E . coli . The amino acid acceptor activity of the reconstituted molecules was 11% and 84% with respect to that of the intact tRNAfMet.

J Gen Microbiol, 1980 Apr, 117(2), 455 - 64
Variant pili produced by mutants of the Flac plasmid; Willetts NS et al.; Transfer-proficient Flac mutants with reduced abilities to plate various F-specific phages were isolated, either by selection after mutagenesis, or as revertants of Flac traA mutants . In many of the mutants pilus-related properties were altered, including physical adsorption of R17 phage, the number of pili per cell and the outgrowth/retraction equilibrium . Complementation studies showed that the mutations were in traA, suggesting that specific alterations in the amino-acid sequence of the pilin subunit protein were responsible for the altered pilus properties . Complementation between the Flac traA mutants and the derepressed plasmid R100-1 restored phage sensitivity in some cases, suggesting that the incorporation of both mutant and R100-1 subunits into the pilus structure may result in conformational changes which increase the capacity of the pilus to interact with phages.

Infect Immun, 1980 Apr, 28(1), 298 - 300
Development of resistance with host age to adhesion of K99+ Escherichia coli to isolated intestinal epithelial cells; Runnels PL et al.; When isolated intestinal epithelial cells from neonatal and older pigs, calves, and mice were tested for adhesion by K99+ enterotoxigenic Escherichia coli, cells from older animals were resistant to adhesion.

Infect Immun, 1980 Apr, 28(1), 190 - 4
Factors affecting expression of the Escherichia coli pilus K99; Isaacson RE; An enzyme-linked antibody centrifuge assay for the detection of Escherichia coli pilus K99 was developed and shown to be a specific and quantitative assay for the detection of cell-bound K99 . The data presented demonstrate the usefulness of the assay as a diagnostic tool . Using the assay, several factors that affect expression of K99 were investigated . Expression of K99 was dependent upon the degree of aeration provided: nonaerated bacteria produced little or no K99, whereas aerated bacteria produced large amounts of K99 . K99 also appeared to be produced only by logarithmically growing cells, whereas there was a demonstrable decline in the amount of K99 per cell during stationary phase . Glucose was shown to repress K99 expression . At 0.5% glucose, K99 expression was highly repressed . Glucose-mediated repression could be overcome by the addition of cyclic adenosine 3',5'-monophosphate . Several other carbon sources also inhibited K99 expression, including pyruvate, arabinose, and lactose; glycerol was stimulatory.

J Bacteriol, 1980 Apr, 142(1), 221 - 8
Mutations in two unlinked genes are required to produce asparagine auxotrophy in Escherichia coli; Felton J et al.; Escherichia coli K-12 has two genes, asnA+ and asnB+, either one of which is able to satisfy the need of cells for asparagine . In order for a strain to have an auxotrophic requirement for asparagine, both genes must be mutationally inactivated . We obtained mutants with Tn5 inserted in asnB . asnB was mapped by conjugation and by three-factor P1 transductions at 15 min on the E coli K-12 linkage map, between ubiF and nagB . Specialized transducing phage lamba 781 supE was shown to carry asnB, as well as supE, ubiF, nagA, and nagB . asnA is the previously mapped ilv-linked asn locus, whiich is between uncB and rbs . E . coli C also has two asn genes, corresponding to asnA and asnB.

J Bacteriol, 1980 Apr, 142(1), 212 - 20
Genetic and biomedical studies demonstrating a second gene coding for asparagine synthetase in Escherichia coli; Humbert R et al.; Genetic experiments have indicated that asparagine auxotrophs of Escherichias coli K-12 can be made asparagine prototrophs at either of two sites on the chromosome and that wild-type strains require both sites to be mutated to produce asparagine auxotrophy . The former asn locus is now called asnA, and the new gene is designated asnB . The asnB gene is located near gal.AsnA+ asnB and asnA asnB+ strains were constructed, and the asparagine synthetic reaction was characterized in extracts . These studies revealed that the asnA gene codes for the enzyme previously described (H . Cedar and J.H . Schwartz, J . Biol . Chem . 244: 4112-4121, 1969), whereas the asnB gene is involved in the production of an enzyme which differs from the one previously described in its specific activity in extracts, its stability at low and high temperatures, and its apparent ability to use either glutamine or ammonia as amide nitrogen donor . Physiological studies showed that either enzyme alone is sufficient to allow a maximal growth rate under conditions of asparagine limitation.

Mol Biol Rep, 1980 Mar 31, 6(1), 31 - 4
Detection of nucleoside triphosphate binding sites of two types in Escherichia coli RNA-polymerase by affinity labeling; Slepneva IA; The affinity labeling of E . coli RNA polymerase by periodate-oxidized uridin triphosphate (o-UTP) has been carried out under the conditions of poly(dA) and poly(dT) transcription . The extent of RNA polymerase labeling proved to be 2.5 times higher under the transcription of poly(dA) as compared to poly(dT) . The amount of o-UTP attached to beta beta'-subunits has been found to decrease if RNA polymerase is labeled in the transcribed complex with poly(dT) . These results as well as those obtained in our previous study (1), suggest that there are two types of binding sites for nucleoside triphosphates and their analogs in E . coli RNA polymerase.

Mol Biol Rep, 1980 Mar 31, 6(1), 51 - 5
Non-coordinate regulation of RNA synthesis in Escherichia coli exposed to 0 degrees C; Guha C et al.; A non-coordinate mode of regulation of RNA synthesis is observed in Escherichia coli cells during exposure to 0 degrees C . The stable RNA synthesis is preferentially inhibited with simultaneous accumulation of messenger RNA . The species of RNA synthesized at 0 degrees C was determined by several criteria such as sedimentation value in sucrose gradients, DNA-RNA hybridization, half life measurements, protein synthesizing capacity and its functional rate of decay . The mode of regulation of RNA synthesis at 0 degrees C is unique and is distinct from the non-coordinate regulation observed during amino acid starvation under stringent control.

Biochim Biophys Acta, 1980 Mar 28, 607(1), 92 - 101
Characterization of a non-histone chromosomal protein which stimulates RNA polymerase II; Legraverend M et al.; A non-histone chromosomal protein was extracted and purified 177-fold from rat liver nuclei which stimulated RNA synthesis in vitro catalyzed by wheat germ RNA polymerase II with either liver chromatin, or native or denaturated calf thymus DNA as template . The stimulatory non-histone chromosomal protein fraction was characterized as having a molecular weight of 66 000 and a pI = 8.2--9.0 . No activity was found with Escherichia coli RNA polymerase and liver chromatin . The binding of the stimulatory non-histone chromosomal protein occurred exclusively with the chromatin template and not with RNA polymerase II as assessed by its interference with actinomycin D but not with alpha-amanitin, respectively.

Biochim Biophys Acta, 1980 Mar 28, 607(1), 65 - 80
The glutaminyl-transfer RNA synthetase of Escherichia coli . Purification, structure and function relationship; Kern D et al.; Glutaminyl-tRNA synthetase from Escherichia coli has been purified to homogeneity with a yield of about 50% . It is a monomer of about 69 000 daltons . Arginyl and glutamyl-tRNA synthetases are also monomeric synthetases of molecular weight significantly lower than 100 000 . In addition it is well known that these three synthetases require their cognate tRNA to catalyze the {32P}PPi-ATP exchange . Like arginyl-tRNA synthetase, but unlike glutamyl-tRNA synthetase, glutaminyl-tRNA synthetase seems to contain some repeated sequences . Therefore no correlation can be established between the tRNA requirement of these synthetases for the catalysis of the isotope-exchange and the presence or the absence of sequence duplication . In the native enzyme four sulfhydryl groups react with dithiobisnitrobenzoic acid causing a loss of both the aminoacylation and the {32P}PPi-ATP exchange activities . The rate-limiting steps of the overall aminoacylation and its reverse reaction correspond, respectively, to the catalysis of the aminoacylation of tRNA Gln and of the the deacylation of glutaminyl-tRNA Gln . At acidic pH, glutaminyl-tRNA synthetase catalyzes the synthesis of the glutaminyl-tRNA Gln and its deacylation at significantly lower rates than the {32P}PPi-ATP exchange, indicating than glutaminyl-tRNA Gln cannot be an obligatory intermediate in this isotope exchange . These results suggest the existence of a two-step aminoacylation mechanism catalyzed by this enzyme.

J Biol Chem, 1980 Mar 25, 255(6), 2524 - 32
Metabolism of individual proteins in exponentially growing Escherichia coli; Mosteller RD et al.; The metabolism of 184 individual proteins was examined in exponentially growing Escherichia coli . Cells were labeled with {3H}leucine and {35S}methionine using either a pulse-chase or a continuous labeling method . Proteins were fractionated by two-dimensional gel electrophoresis and their stabilities relative to total protein were determined from the 3H/35S ratios . Forty-seven proteins appeared to be unstable and were probably either degraded or modified to electrophoretically distinct forms . The apparent half-lives of these proteins calculated from the pulse-chase data varied from 2.0 to 23 h . Twenty-seven proteins appeared to be products of post-translational modifications . One hundred fourteen proteins appeared to be stable . The molar ratios of leucyl and methionyl residues in individual proteins and in total protein were calculated by comparing their 3H/35S ratios to that of a protein with known amino acid composition . These values varied from 1.7 to 12 . The half-lives of the unstable proteins did not exhibit a correlation with protein molecular weights, isoelectric points, or leucine/methionine ratios . It may be significant, however, that 6 of the 10 most unstable proteins had low leucine/methionine ratios whereas only 11% of all proteins tested had similarly low ratios.

J Biol Chem, 1980 Mar 25, 255(6), 2332 - 42
Structure and biosynthesis of surface polymers containing polysialic acid in Escherichia coli; Rohr TE et al.; Membranous sialyltransferase complexes from Escherichia coli K-235 catalyze the synthesis of surface polymers containing alpha-2,8-ketosidically linked polysialic acid . Undecaprenyl phosphate functions as an intermediate carrier of sialic acid (NeuNAc) residues between cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NeuNAc) and an endogenous acceptor (Troy, F.A., and McCloskey, M.A . (1979) J . Biol . Chem 254, 7377-7387) . In vitro pulse-chase experiments now confirm that polymer elongation occurs by the addition of sialyl residues to the nonreducing termini of growing nascent chains . Sequential periodate oxidation and borohydride reduction of radiolabeled polysialic acid was used to quantitatively convert the terminal, nonreducing sialic acid to the 7-carbon analogue, 5-acetamido-3,5-dideoxy-L-arabino-2-heptulosonic acid (NeuNAc7) . After complete hydrolysis of the polymers by neuraminidase, the ratio between NeuNAc and NeuNAc7 was used to determine the average degree of polymerization (D.P.) . The membrane preparations used as a source of enzyme contained endogenous sialyl polymers that averaged 165 residues in length . During the first phase of in vitro synthesis, lasting about 90 min, 40 to 45 sialyl residues were transferred onto these endogenous acceptors . Subsequent in vitro incorporation increased at a slower, constant rate for at least 16 h . During this second phase of synthesis, the D.P . of newly synthesized chains remained relatively constant while the number of nonreducing terminal end groups, a measure of the number of new sialyl chains, increased . These results establish that individual polymer chains are rapidly elongated in vitro to a defined length of about 200 sialyl residues, then terminated and new chains started . The mechanism signaling chain termination, translocation of the sialyltransferase to a new acceptor, and chain reinitiation remains to be determined . Endogenous and enzymatically synthesized sialyl polymers were solubilized with Triton X-100 and purified to apparent homogeneity . Sialic acid accounted for approximately 93% of the mass of these polymers which had no free reducing terminal sialic acid . This position of the molecule is presumably occupied by an as yet unidentified component which links the sialyl polymer to the membrane.

Nucleic Acids Res, 1980 Mar 25, 8(6), 1373 - 81
Endonucleases for UV-irradiated and depurinated DNA in barley chloroplasts; Veleminsky J et al.; Lysates of barley chloroplasts release more radioactivity into acid soluble form from UV-irradiated and alkylated-depurinated E . coli {3H} DNA than from intact DNA . By means of affinity chromatography on depurinated DNA-cellulose and/or UV irradiated DNA-cellulose and by electrophoresis in polyacrylamide gels, four activities on depurinated DNA were separated . One of these contained activity against heavily UV-irradiated /270 J.m-2/ native DNA . In addition, two other nucleases specific towards UV-DNA were separated . One of them was active on native and heat denatured DNA irradiated with 10 J . m-2 UV, whereas the other was predominantly active on native UV-irradiated DNA.

Nucleic Acids Res, 1980 Mar 25, 8(6), 1187 - 99
Complete nucleotide sequence of a cloned chicken alpha-globin cDNA; Deacon NJ et al.; Chicken globin double-stranded cDNA was synthesised from anaemic adult reticulocyte alpha- and beta-globin mRNA and ligated into the Hind III site of pBR322 using synthetic Hind III decamers . Transformation of E . coli x1776 resulted in the production of a number of alpha- and beta-cDNA clones . One of the alpha-type clones (pCG alpha-8) was fully sequenced and found to code for neither alpha A- nor alpha D-globin . Partial sequencing of the other alpha-cDNA clones indicates that they are all of the same type.

Nucleic Acids Res, 1980 Mar 25, 8(6), 1357 - 72
The binding of T4 gene 32 protein to MS2 virus RNA and transfer RNA; Suau P et al.; Fluorescence titrations, absorption spectroscopy and stopped-flow techniques were used to study the interaction of T4 coded 32-protein (P 32) with MS2 RNA and total tRNA from E . coli under different ionic conditions . It is shown that the amount of MS2 RNA and tRNA secondary structure melted by P 32 varies markedly and reversibly within a range of ionic conditions under which the binding constant of P 32 to single-stranded nucleic acids unable to form stable hairpins remains higher than 10(8) M-1 . Kinetic experiments suggest that P 32 dissociates from the MS2 RNA rewinding strand with a similar rate constant as calculated for the dissociation from single-stranded regions . Possible in vivo consequences of these findings are discussed.

Nucleic Acids Res, 1980 Mar 25, 8(6), 1319 - 37
Characterization of cloned cDNA sequences derived from Xenopus laevis poly A(+) oocyte RNA; Jacob E; Double-stranded cDNA sequences were prepared from Xenopus laevis ovary poly A(+) RNA with AMV reverse transcriptase and nuclease S1 . They were inserted into the plasmid pBR 322 after ligation with a Hind III linker and were cloned in E . coli strain X1776 . Plasmid pools containing a cDNA insert were identified by Hind II restriction and hybridization of the DNA fragments with radiolabelled pBR 322 DNA . Hybridization of the positive pools with ovary RNA labelled in vitro led to the identification of cloned cDNA sequences which represent RNA species of high to intermediate abundance in the ovary . Positive clones were further challenged with in vitro labelled mitochondrial DNA and RNA from different developmental stages . One clone of mitochondrial origin has been detected . The hybridization characteristics of the cDNA sequences with the RNA probes from later developmental stages is discussed.

Nucleic Acids Res, 1980 Mar 25, 8(6), 1259 - 72
An improved direct RNA sequence method; its application to Vicia faba 5.8S ribosomal RNA; Tanaka Y et al.; We have developed a direct read-off sequencing procedure, based on the method of Stanley and Vassilenko using E . coli 5S ribosomal RNA as a model compound . Radioactive bands were transferred from an acrylamide gel fractionation in the first dimension onto a DEAE-cellulose thin layer plate . After in situ enzymatic digestion with RNase T2, mononucleoside 3',5'-diphosphates were separated in the second dimension by electrophoresis at pH 2.3 . Using this two-dimensional procedure the entire sequence of 163 residues of the previously unknown Vicia faba (broad bean) 5.8S ribosomal RNA was deduced.

Biochemistry, 1980 Mar 18, 19(6), 1053 - 8
Reversible dissociation of wheat germ ribosomal subunits: cation-dependent equilibria and thermodynamic parameters; Sperrazza JM et al.; The influence of magnesium ion concentration upon the equilibrium between the wheat germ ribosome and its subunits has been studied by light scattering . The curves obtained for ribosome dissociation and subunit reassociation were identical and were independent of the origin and direction of the magnesium ion titration, suggesting that the wheat germ ribosomes are behaving as a homogeneous population equivalent to Escherichia coli type A ribosomes . Increasing K+ concentrations in the presence of Mg2+ favored ribosome dissociation . Polyamines favored subunit reassociation, with 0.1 mM spermine acting as effectively as 1 mM spermidine . Thermodynamic parameters have been determined from the temperature-dependent equilibria and have been compared to those of E . coli type A ribosomes . The association of the 40S and 60S subunits is exothermic . At 1.5 mM Mg2+ and 100 mM K+, the entropy term is negative, favoring ribosome dissociation, and contributes less to the free energy than the enthalpy term . The determination of these thermodynamic parameters was based on molecular weights of 1.2 x 10(6) and 2.3 x 10(6) for the 40S and 60S subunits, respectively, calculated from laser light scattering data.

Biochemistry, 1980 Mar 18, 19(6), 1234 - 40
Escherichia coli elongation factor G blocks stringent factor; Wagner EG et al.; The relationship between the binding domains of elongation factor G(EF-G) and stringent factor (SF) on ribosomes was studied . The binding of highly purified, radioactively labeled, protein factors to ribosomes was monitored with a column system . The data show that binding of EF-G to ribosomes in the presence of fusidic acid and GDP or of the noncleavable analogue GDPCP prevents subsequent binding of SF to ribosomes . In addition, stabilization of the EF-G-ribosome complex by fusidic acid inhibits SF's enzymatic activities . Removal of protein L7/L12 from ribosomes leads to weaker binding of EF-G, while SF's binding and activity are unaffected . In the absence of L7/L12, EF-G-dependent inhibition of SF binding and function is reduced . The data presented in this report suggest that these two factors bind at overlapping, or at least interacting, ribosomal domains.

C R Seances Acad Sci D, 1980 Mar 17, 290(11), 699 - 701
{DNA synthesis and antibody formation in spleen cells of the mouse after in vivo immunization by Escherichia coli lipopolysaccharide modified by polymyxin B}; Dufer J et al.; The addition of polymyxin B to Escherichia coli lipopolysaccharide alters some properties of this molecule, when injected to the Mouse . Spleen cells DNA synthesis was inhibited and delayed when the other functions tested: specific antibody synthesis ad immunoglobulin synthesis were unchanged . The possible implications of this dissociation are discussed.

Biochim Biophys Acta, 1980 Mar 14, 612(1), 286 - 94
Affinity labeling of a cysteine at or near the catalytic center of Escherichia coli B DNA-dependent RNA polymerase; Miller JA et al.; 9-beta-D-Arabinofuranosyl-6-thiopurine was used to affinity label DNA-dependent RNA polymerase isolated from Escherichia coli B . This substrate analogue displayed competitive type inhibition which could be reversed by addition of a thiol reagent, such as dithiothreitol, while exposure to hydrogen peroxide, a mild oxidizing agent, caused an increase in both the inhibitory and enzyme binding capability of arabinofuranosyl thiopurine . Chromatographic analysis of the products obtained by pronase digestion of the 9-beta-D-arabinofuranosyl-6-{35S}thiopurine-enzyme complex suggests that disulfide bond formation occurs between the inhibitor and a cysteine residue located in or near the active center of the enzyme . In addition, polyacrylamide gel electrophoresis indicated that the arabinofuranosyl thiopurine moeity was bound to the beta' subunit of the enzyme.

J Biol Chem, 1980 Mar 10, 255(5), 2220 - 5
Primary structure of Escherichia coli tRNA UUR Leu . Presence of an unknown adenosine derivative in the first position of the anticodon which recognizes the UU codon series; Yamaizumi Z et al.; The primary structure of Escherichia coli tRNA UUR Le which recognizes the UU series of codons has been determined . The sequence is pG-C-C-C-G-G-A-s4U-G-G-U-G-G-A-A-D-C-Gm-C-D-A-G-A-C-A-C-A-A-G-G-G-A-psi-U-N-A-A-ms2i6A-A-psi-C-C-C-C-U-C-G-G-C-G-G-C-G-U-U-C-G-C-G-C-U-G-U-G-C-G-G-G-T-psi-C-A-A-G-U-C-C-C-G-C-U-C-C--G-G-G-U-A-C-C-A . The chain length of tRNA UUR Leu is 87 residues, the same as other E . coli tRNA Leu s and T4 phage-coded tRNA Leus . Its sequence is especially similar to that of E . coli tRNA2 Leu in the Darm and T psi C arm regions . E . coli tRNA UUR Leu contains an unknown modified nucleoside in the first position of the anticodon and was shown by mass spectrometry and chemical degradation to be an adenosine derivativee . Addition of tRNA UUR Leu to a cell-free protein-synthesizing system with high Mg2+ concentration resulted in the formation of polyleucine miscoded by poly(U), indicating that the unknown modified nucleoside exhibits a tendency to recognize U under certain conditions.

J Biol Chem, 1980 Mar 10, 255(5), 2160 - 3
Identification of a cytidine-specific ribonuclease from chicken liver; Boguski MS et al.; Rapid RNA sequencing technology was used to determine if the base specificities of an RNase recently purified from chicken liver would prove useful for RNA sequence analysis . Escherichia coli 5 S {5'-32P}rRNA or yeast 5.8 S {5'-32P}rRNA was digested with the enzyme and this digest, along with digests derived from RNases of known specificity (U2, T1, T2) were subjected to electrophoresis through denaturing polyacrylamide slab gels . Following autoradiography, the banding patterns arising from the activity of each enzyme were compared, and the base specificity of the unknown RNase was established . The chicken liver RNase was found to have a marked preference for phosphodiester bonds containing cytidylic acid residues, a property which should make the enzyme useful for distinguishing between pyrimidines in RNA sequencing.

J Biol Chem, 1980 Mar 10, 255(5), 1956 - 61
The catalytic mechanism of the glutamyl-tRNA synthetase from Escherichia coli . Detection of an intermediate complex in which glutamate is activated; Kern D et al.; Up to now it was not possible to isolate an enzyme . adenylate complex after mixing the glutamyl-tRNA synthetase from Escherichia coli with ATP, MgCl2, and glutamate . This enzyme catalyzes an AMP-dependent and PPi-independent deacylation of Glu-tRNAGlu . The labeled glutamate which disappears from Glu-tRNAGlu in the presence of AMP remains linked to the enzyme in a complex isolated by filtration on nitrocellulose discs . The addition of tRNAGlu to this reaction mixture at the deacylation plateau gives rise to a synthesis of Glu-tRNAGlu, via an ATP-independent reaction . These results indicate the existence of the following equilibrated reaction catalyzed by the glutamyl-tRNA synthetase E + Glu-tRNAGlu + AMP in equilibrium E . AMP approximately Glu + tRNAGlu . This transfer of glutamate from an activated complex to tRNAGlu indicates that the formation of glutamyl-tRNA is catalyzed via a two-step reaction mechanism . The AMP-dependent and PPi-independent deacylation of Glu-tRNAGlu is the rate-limiting step of the reverse of the AMP- and PPi-dependent deacylation.

J Biol Chem, 1980 Mar 10, 255(5), 1830 - 3
Regulation of ribosomal and transfer RNA synthesis by guanosine 5'-diphosphate-3'-monophosphate; Pao CC et al.; Permeabilized cells of Escherichia coli were used to examine the effect on RNA synthesis of guanosine 5'-diphosphate-3'-monophosphate (ppGp) . Electrophoretic and hybridization analysis of bulk RNA demonstrated that ppGp selectively reduced the accumulation of both ribosomal and transfer RNAs . The experiments further suggested that the observed reduction in stable RNA accumulation resulted from a reduction in stable RNA chain initiation rather than an effect on elongation, processing, or maturation of stable RNA transcripts . In contrast, the expression of the lac Z gene was not affected by ppGp . These results suggest that ppG, a nucleotide produced in E . coli during the stringent response, could play a direct role in the stringent regulation of stable RNA synthesis.

J Biol Chem, 1980 Mar 10, 255(5), 1763 - 6
Characterization of promoter containing DNA fragments based on the abortive initiation reaction of Escherichia coli RNA polymerase; Cech CL et al.; The abortive initiation reaction of Escherichia coli RNA polymerase was demonstrated to be a general method for the rapid identification and quantitation of promoter sites on DNA . The presence of the T7 promoters, A1, A2, A3, and D on an isolated restriction fragment of the phage template was demonstrated . In addition, abortive initiation results indicated that the D promoter transcript started with pppGpUpUpG . This technique should prove particularly useful for screening DNA fragments for the number and type of promoters present.

Biochemistry, 1980 Mar 4, 19(5), 883 - 90
Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system . Evidence that the dimer is the active form of enzyme I; Misset O et al.; In vitro kinetic measurements have been performed by using purified HPr, EI, and a membrane fraction of EII from the Escherichia coli phosphoenolypyruvate-dependent sugar transport system . These measurements reveal very large lag times in the formation of methyl alpha-glucoside phosphate which are a function of the EI and the EII concentrations . The lag times decrease with increasing concentrations of EI but they increase with increasing concentrations of EII . When EI, together with Mg2+ and phosphoenolpyruvate, is preincubated at 37 degrees C before starting the kinetic measurements, the lag time can be decreased or eliminated . We have shown that the process responsible for the lag time is the activation of EI by dimerization which is influenced by Mg2+ and phosphoenolpyruvate.

Biochemistry, 1980 Mar 4, 19(5), 842 - 8
Mechanism of ribonucleic acid chain initiation . 1 . A non-steady-state study of ribonucleic acid synthesis without enzyme turnover; Shimamoto N et al.; A non-steady-state kinetic method has been developed to observe the initiation of long RNA chains by Escherichia coli RNA polymerase without the enzyme turnover . This method was used to determine the order of binding of the first two nucleotides to the enzyme in RNA synthesis with the first two nucleotides to the enzyme in RNA synthesis with poly(dA-dT) as the template . It was shown that initiator {ATP, uridyly(3'-5')adenosine, or adenyly(3'-5')uridylyl-(3'-5')adenosine} binds first to the enzyme-template complex, followed by UTP binding . The concentration dependence of UTP incorporation into the initiation complex suggests that more than one UTP molecule may bind to the enzyme-DNA complex during the initiation process . Comparison of the kinetic parameters derived from these studies with those obtained under steady-state conditions indicates that the steps involving binding of initiator or UTP during initiation cannot be rate limiting in the poly(dA-dT)-directed RNA synthesis . The non-steady-state technique also provides a method for active-site titration of RNA polymerase . The results show that only 36 +/- 9% of the enzyme molecules are active in a RNA polymerase preparation of high purity and specific activity . In addition, the minimal length of poly(dA-dT) involved in RNA synthesis by one RNA polymerase molecule was estimated to be approximately 500 base pairs.

Cancer Res, 1980 Mar, 40(3), 620 - 4
Comparisons of liver transfer RNA methyltransferase and adenosylmethionine decarboxylase activities of male and female rats; Wainfan E et al.; The activities of liver transfer RNA (tRNA) methyltransferases from control or ovariectomized female rats were found to be higher than those of control or castrated males . Administration of testosterone to ovariectomized females caused activity to decrease to the level of the males . Conversely, administration of estrogen to castrated males resulted in liver enzyme levels similar to those of the females . When the substrates for in vitro methylation were either mixed heterologous tRNA's from Escherichia coli or mixed homologous methyl-deficient tRNA from livers of ethionine-treated rats, the difference in activity between males and females was about 35% . When amino acid-specific tRNA's from E . coli were used as substrates, the ratios of activity of enzymes from females to that of males were: tRNANfMet 1.5; tRNAMetMet 1.1; tRNASer3 1.85; tRNAPhe 1.1; and tRNATyr 1.25, indicating that there are qualitative as well as quantitative differences in the liver tRNA methyltransferases of the two sexes . The adenosylmethionine decarboxylase activity of female rat liver preparations was approximately double that found for males . Testosterone, given to ovariectomized females, lowered the activity of this enzyme to about the same level as that of males . It is not clear whether the observed sex-related differences in activity of several adenosylmethionine-utilizing liver enzymes represent isolated phenomena or are indicative of a sex-related difference in the rate of liver adenosylmethionine turnover.

Gene, 1980 Mar, 8(4), 391 - 417
The isolation of plasmids containing DNA complementary to messenger RNA for variant surface glycoproteins of Trypanosoma brucei; Hoeijmakers JH et al.; We have isolated poly(A)+ RNA from four antigenic variants (117, 118, 121, 221) of one clone of Trypanosoma brucei . Translation of these poly(A)+ RNAs in a rabbit reticulocyte lysate gave rise to proteins that could be precipitated with antisera against homologous variant surface glycoprotein, the protein responsible for antigenic variation in trypanosomes . From the electrophoretic mobility of these in vitro products in sodium dodecyl sulphate (SDS) gels we infer that variant surface glycoproteins (VSGs) are made as pre-proteins, which require trimming to yield mature VSGs . The total translation products from the four poly(A)+ RNAs produced a complex set of bands on SDS gels, which only differed in the region where the variant pre-glycoproteins migrated . The only detectable variation in the messenger RNA populations of these variants is, therefore, in the messenger RNA for variant pre-glycoproteins . We have made duplex DNA copies of these poly(A)+ RNAs, linked the complementary DNA to plasmid pBR322 by GC tailing and cloned this recombinant DNA in Escherichia coli . Colony hybridization with complementary DNA made on poly(A)+ RNA showed that 7--10% of the colonies contained DNA that hybridized only with the homologous probe . Plasmid DNA was isolated from ten such colonies (two or three of each variant complementary DNA), bound to diazobenzyloxymethyl-cellulose (DBM) paper and used to select complementary messenger RNA from total poly(A)+ RNA by hybridization . In eight cases the RNA recovered from the filter gave variant pre-glycoprotein as the predominant product of in vitro translation . Poly(A)+ RNA from each of the variants only hydridized to the homologous complementary DNA in filter hybridizations . Each trypanosome variant, therefore, contains no detectable messenger RNAs for the three heterologous variant-specific glycoproteins tested . We conclude from this lack of cross-hybridization that antigenic diversity in trypanosomes, unlike antibody diversity in mammals, does not involve the linkage of a repertoire of genes for the variable N-terminal half to a single gene for the C-terminal half of the VSGs.

Biophys J, 1980 Mar, 29(3), 351 - 66
X-ray scattering from randomly oriented superhelices . Circular superhelical DNA; Benham CJ et al.; The scattering functions of randomly oriented filaments of finite length exhibiting two orders of helicity have been calculated . It is shown to a good approximation that each order scatters as if present alone as a first order helix of the same contour length and pitch angle . These results show that the measured scattering pattern from dissolved superhelical DNA molecules is consistent with the scattering pattern calculated for a coiled coil geometry.

Biken J, 1980 Mar, 23(1), 49 - 51
Dominance of alkaline phosphatase isozyme gene (IAP+) of Escherichia coli K-12; Nakata A et al.; A mutation (iap-) causing a defect in the conversion of alkaline phosphatase isozymes of Escherichia coli K-12 is recessive to the wild type allele . The product of the iap+ gene is diffusible.

Trop Geogr Med, 1980 Mar, 32(1), 16 - 8
Effect of partial treatment on purulent meningitis; Singh M et al.; Various clinical and laboratory parameters were used for comparing 49 previously untreated and 55 partially treated children with purulent meningitis . The percentage of cases having fever, convulsions, unconsciousness and bulging anterior fontanel was almost the same in both groups . There was no difference in the cellular response and protein content of the cerebrospinal fluid . A Gram smear was positive in 32.6% of untreated and in 47.2% of partially treated patients . Percentages for a positive CSF culture were 38.7 and 50.9%; for CSF sugar of less than 40 mg, 59.1 and 72.7% respectively . The case fatality rate was the same in both groups . These observations suggest that partial treatment neither masks clinical and laboratory findings nor affects the case fatality rate in purulent meningitis in children.

J Gen Microbiol, 1980 Mar, 117(1), 257 - 62
A mutant defective in electron transfer to nitrate in Escherichia coli K12; Orth V et al.; A mutant of Escherichia coli K12 is described which is unable to reduce nitrate with a variety of physiological electron donors but which retains nitrate reductase activity with the artificial electron donor benzyl viologen . It is suggested that the affected gene, chlI, located close to chlC, encodes the cytochrome bNR apoprotein.

J Gen Microbiol, 1980 Mar, 117(1), 127 - 34
The effect of methyl glyoxal on cell division and the synthesis of protein and DNA in synchronous and asynchronous cultures of Escherichia coli B/r; Fraval HN et al.; Methyl glyoxal inhibits the growth of Escherichia coli in synchronous and asynchronous culture . The inhibition of growth is accompanied by immediate inhibition of protein synthesis and of the initiation of replication of DNA . When methyl glyoxal is added after initiation of a round of replication the elongation of new DNA chains is not inhibited . Cell division is inhibited if methyl glyoxal is added up to about 22 min prior to division . These results support the view that the primary effect of methyl glyoxal is on protein synthesis.

Inflammation, 1980 Mar, 4(1), 37 - 44
Alteration of polymorphonuclear leukocyte surface charge by endogenous and exogenous chemotactic factors; Schaack TM et al.; We investigated the effects of chemotaxins on the surface charge of isolated human PMN . Chemotaxis was ascertained using Boyden chambers . Surface charge was calculated using data derived from cell mobility as measured in a cytophorometer . The electrophoretic mobility of cells exposed to all chemotactic agents studied was altered . Endotoxin-activated serum containing C5a, PMN lysosomal extracts from "resting" and from crystal-stimulated cells, and Gly-His-Gly, a synthetic tripeptide, all significantly reduced the net negative surface charge of isolated neutrophils . Only chemotactically active substances effected this change; controls including heat-inactivated serum, other subcellular fractions, and an inert tripeptide, Gly-Gly-Gly, did not alter cell mobility in an electric field . These findings are consistent with studies by others on the effects of chemotactic factors on cation fluxes and cell aggregation and suggest a possible mechanism by which PMN directional migration is regulated.

Z Naturforsch {C}, 1980 Mar-Apr, 35(3-4), 279 - 83
Thymineless death in recombination deficient mutants of Escherichia coli K12; Ahmad SI; When grown in thymine-free minimal synthetic medium, thyA recA mutants of Escherichia coli K12 were comparatively more resistant and thyA recBC mutants more sensitive to thymineless death (TLD) than their respective parent strains . No excessive numbers of single-strand breaks were observed in the DNA of the recBC mutant strain starved for thymine, hence the hypersensitivity for TLD in this strain was not caused by this type of DNA damage . Although experiments were performed with the same recBC mutant strain as used by earlier workers, results presented here contradict earlier findings that recBC mutants are no more sensitive and recA mutants are no more resistant to TLD.

Mutat Res, 1980 Mar, 77(3), 241 - 4
Mutagenicity of nifurtimox in Escherichia coli; Ohnishi T et al.; The effects of nifurtimox, a nitrofuran derivative, on killing and mutation induction in 3 Escherichia coli strains having different DNA-repair systems for UV lesion were studied and compared with the effects of furylfuramide . Nifurtimox induces mutations at a high frequency in both Hs3OR (uvrA-) and H/r30R (radiation-resistant), although no significant killing effect is detected with Hs30R . No significantly induced mutation frequency could be detected with NG30 (recA-), which is very sensitive to killing by nifurtimox . The characteristics of lesions of DNA induced by nifurtimox and the mechanism of mutation induction in Hs30R are discussed.

Infect Immun, 1980 Mar, 27(3), 903 - 9
Breast milk lymphocyte response to K1 antigen of Escherichia coli; Keller MA et al.; Comparison milk and blood lymphocyte blastogenic responses to the K1 antigen of Escherichia coli and lipopolysaccharide (LPS) from E . coli O127,B8 were examined in 16 postpartum women by {3H}thymidine uptake . Rabbit hemolysincoated sheep erythrocyte monolayers were used to deplete macrophages from milk lymphocyte preparations and to enrich for T lymphocytes in order to make milk preparations more comparable to blood preparations . Response was defined as a stimulation index of greater than or equal to 2.0 . There was no evidence of selective response to K1 antigen by milk lymphocytes, since both blood and milk lymphocytes responded in four women and neither blood nor milk lymphocytes responded in nine . Milk lymphocytes alone responded to K1 in one woman, whereas blood lymphocytes alone responded in two women . Additional nonpaired milk or blood cultures were available from three women . None of these responded to K1 antigen . Corresponding lymphocyte cultures were stimulated with LPS . A positive K1 response was always accompanied by an LPS response, and the LPS response correlated with the K1 response in 17 of 19 women . Stool cultures examined with an antiserum agar showed no correlation between the presence of K1 E . coli in the stool and milk or blood lymphocyte response to K1 antigen . In the system used here, no selectivity of response of breast milk lymphocytes to K1 antigen was noted.

Proc Natl Acad Sci U S A, 1980 Mar, 77(3), 1326 - 30
Primary structure of elongation factor Tu from Escherichia coli; Arai K et al.; The amino acid sequence of elongation factor Tu (EF-Tu) from Escherichia coli has been determined . EF-Tu is a single-chain polypeptide composed of 393 amino acids (Mr 43,225 for the species bearing COOH-terminal serine) . The NH2-terminal serine is acetylated, and lysine-56 is partially methylated . The sites of facile tryptic cleavage are at arginines 44 and 58 and at lysine-263 . The cysteinyl residues associated with aminoacyl-tRNA and guanosine nucleotide binding activities are residues 81 and 137, respectively . The COOH-terminal amino acid is heterogenous in that analyses of the COOH-terminal peptides isolated from different EF-Tu preparations gave position 393 as glycine and serine in ratios (Gly/Ser) ranging from about 0.7 to 3.

Am J Physiol, 1980 Mar, 238(3), H325 - 30
Lipoprotein lipase activity in rat heart and adipose tissue during endotoxic shock; Bagby GJ et al.; The present studies were designed to delineate changes in heart and adipose tissue lipoprotein lipase (LPL) activity following the administration of E . coli endotoxin . Plasma triglyceride levels were elevated in animals given endotoxin compared to saline-injected controls . Heart LPL activity decreased from 126.4 mumol fatty acid released per gram wet wt per hour in control rats to less than 22.5 mumol . g-1 . h-1 by 7 h following the injection of endotoxin . Although endotoxin was administered in doses producing 0-100% mortalities in a 24-h period, myocardial LPL activity was depressed to the same extent (75-80%) regardless of dose . The response of adipose tissue was less pronounced . Epididymal fat pad LPL activity fell significantly over the 24-h observation period in control and endotoxin-treated rats with the latter group somewhat more depressed 7 h after treatment . The findings are consistent with the suggestion that hypertriglyceridemia often observed during endotoxic shock may be related to depressed LPL activity; the degree of depression is probably tissue dependent.

Acta Paediatr Scand, 1980 Mar, 69(2), 219 - 24
Enterotoxigenic and invasive Escherichia coli as causes of childhood diarrhoea in Finland; Maki M et al.; E . coli was considered as the possible aetiologic agent in 16 cases (5.7%) of 283 hospital admissions for diarrhoea . One invasive strain was isolated from a case with exudative diarrhoea . Four heat-labile (LT) enterotoxin-producing strains were found in relatively mild cases of diarrhoea . Eleven strains belonged to "classic" pathogenic serotypes (EPEC); 9 of these were endemic cases and 2 associated with travel . Of the latter, 1 strain (078) was also found to produce heat-stable (ST) enterotoxin detectable by infant mouse assay . Although EPEC are now found much less frequently than 20 years ago, E . coli as a whole may still be the most common bacterial aetiology of childhood diarrhoea in Finland.

J Bacteriol, 1980 Mar, 141(3), 1421 - 3
Inhibition of canavanyl-protein proteolysis in Escherichia coli by rifampin; George GN et al.; Rifampin inhibited the intracellular proteolysis of canavanine-induced, rapidly sedimenting protein complexes in Escherichia coli.

J Bacteriol, 1980 Mar, 141(3), 1409 - 20
Protein identifications of O'Farrell two-dimensional gels: locations of 81 Escherichia coli proteins; Bloch PL et al.; The two-dimensional gel electrophoresis method of P . H . O'Farrell readily resolves approximately 1,000 proteins from whole-cell homogenates . We have found that the location of most individual proteins is sufficiently reproducible and precise to permit different laboratories to exchange information about them . We present the location of 81 Escherichia coli structural proteins, binding proteins, enzymes, and factors, identified with the aid of purified proteins supplied to us by many investigators.

J Bacteriol, 1980 Mar, 141(3), 1192 - 8
Stimulation of deoxyribonucleic acid replication fork movement by spermidine analogs in polyamine-deficient Escherichia coli; Geiger LE et al.; We examined the rate of deoxyribonucleic acid (DNA) replication fork movement in polyamine-deficient cells of Escherichia coli by two independent techniques . DNA autoradiography was used to directly visualize the length of DNA produced during a given time interval, and replication rates were calculated . The amount of DNA synthesized after blocking protein synthesis also allowed calculation of replication rates . We found that the DNA chain elongation rate in polyamine-deficient cells was about half that of putrescine- or spermidine-supplemented cells . We also found that spermidine homologs of increasing chain length, when present at equal intracellular concentrations, exhibited a decreasing ability to support growth and the rate of DNA replication fork movement . The kinetics of recovery of DNA synthesis from the polyamine-deficient state were also investigated . A new rate of DNA synthesis was reached about 20 min after addition of spermidine to polyamine-limited cells . The rise in the rate of DNA synthesis was preceded by a rise in the intracellular concentration of spermidine.

J Bacteriol, 1980 Mar, 141(3), 1163 - 9
Mutation in the structural gene for seryl-transfer ribonucleic acid synthetase of Escherichia coli which affects formation of its gene product at high temperature; Hill RJ et al.; The rate of formation of seryl-transfer ribonucleic acid (tRNA) synthetase activity was temperature dependent in a temperature-sensitive mutant of Escherichia coli (K28) with an altered seryl-tRNA synthetase structural gene and in a class of spontaneous revertants derived from it . These revertants, which were selected by their ability to grow at 45 degrees C, had high levels of the thermolabile enzyme . The rate of formation of seryl-tRNA synthetase activity in the mutant and in the revertants fell from 100% to near zero with a 4 degrees C temperature range from 40 to 44 degrees C . The temperature-dependent rate of formation of seryl-tRNA synthetase activity was reversible . Dropping the temperature from 44 to 37 degrees C resulted, after a 2- to 3-min delay, in a resumption of the initial rate of formation of enzyme activity . The results could not be accounted for by in vivo or in vitro degradation of the active enzyme . Addition of rifampin just before the temperature shift down from 44 to 37 degrees C inhibited the appearance of seryl-tRNA synthetase activity at the lower temperature . Explanations which might account for these phenomena are proposed.

J Bacteriol, 1980 Mar, 141(3), 1148 - 56
Coordination between chromosome replication and cell division in Escherichia coli; Tang MS et al.; Cell division properties of Escherichia coli B/r containing either a dnaC or a dnaI mutation were examined . Incubation at nonpermissive temperature resulted in the eventual production of cells of approximately normal size, or slightly smaller, which lacked chromosomal DNA . The cell division patterns in cultures which were grown at permissive temperature and then shifted to nonpermissive temperature were consistent with: first, division and equipartition of chromosomes by cells which were in the C and D periods at the time of the shift; second, an apparent delay in cell division; and third, commencement of the formation of chromosomeless cells . In glucose-grown cultures of the dnaI mutant, production of chromosomeless cells continued for at least 120 min, whereas in the dnaC mutant chromosomeless cells were formed during a single interval between 110 and 130 min after the temperature shift . The results are discussed in light of the hypothesis that replication of a specific chromosomal region is not an obligatory requirement for the initiation and completion of the processes leading to division in a cell which contains at least one functioning chromosome.

J Bacteriol, 1980 Mar, 141(3), 1047 - 51
Composition of cardiolipin molecular species in Escherichia coli; Yokota K et al.; The composition of the molecular species of acidic phospholipids in Escherichia coli B during the late exponential growth phase at 37 degrees C was determined . Two phosphatidyl groups of cardiolipin, the 3-(3-sn-phosphatidyl) and 1-(3-sn-phosphatidyl) moieties of cardiolipin, were isolated by limited hydrolysis with phospholipase C . No significant difference in the composition of the molecular species was found between the 3-(3-sn-phosphatidyl) and 1-(3-sn-phosphatidyl) moieties . On the other hand, the composition of the molecular species of phosphatidylglycerol was different from that of cardiolipin . Phosphatidylglycerol contained more of the 1-palmitoyl 2-cis-9,10-methylenehexadecanoyl and 1-palmitoyl 2-cis-11,12-methyleneoctadecanoyl species than did cardiolipin . The difference in the composition of the molecular species between cardiolipin and phosphatidylglycerol may depend on the difference in the turnover rates of both phospholipids.

J Bacteriol, 1980 Mar, 141(3), 1031 - 6
Melibiose transport of Escherichia coli; Tanaka K et al.; Transport of {3H}melibiose, prepared from {3H}raffinose, was investigated in Escherichia coli . Na+ stimulated the transport of melibiose via the melibiose system, whereas Li+ inhibited it . Kinetic parameters of melibiose transport were determined . The Kt values were 0.57 mM in the absence of Na+ or Li+, 0.27 mM in the presence of 10 mM NaCl, and 0.29 mM in the presence of 10 mM LiCl . The Vmax values were 40 and 46 nmol/min per mg of protein in the absence and in the presence of NaCl and 18 nmol/min per mg of protein in the presence of LiCl . Melibiose transport via the melibiose system was temperature sensitive in a wild-type strain of Escherichia coli and was not inhibited by lactose . On the other hand, melibiose uptake via the lactose system was not temperature sensitive, was inhibited by lactose, and was not affected by Na+ and Li+ . Methyl-beta-D-thiogalactoside, a substrate for both systems, inhibited the transport of melibiose via both systems.

J Bacteriol, 1980 Mar, 141(3), 1024 - 30
Replication of ColE1 plasmid deoxyribonucleic acid in a thermosensitive dnaA mutant of Escherichia coli; Abe M; The replication of ColE1 deoxyribonucleic acid (DNA) took place at the restrictive temperature in a dnaA mutant, dnaA167(Ts) . It proceeded at a constant rate at 42 degrees C for at least 3 h . The replication was insensitive to rifampin, which blocked replication at the permissive temperature or in the presence of chloramphenicol, even at the restrictive temperature . A linear DNA strand of ColE1 longer than unit genome size was synthesized . The structure of the replicating molecules observed by electron microscopy was mostly sigma shaped, composed of a circle of a unit genome length with a double-stranded tail . These observations suggest that the replication of ColE1 DNA proceeds via a rolling-circle type of structure in the absence of dnaA function.

Eur J Biochem, 1980 Mar, 104(2), 459 - 67
Transcription of Friend virus proviral sequences in isolated nuclei; Brown TD et al.; Transcription studies using isolated Friend nuclei and Escherichia coli polymerase are presented . Combination of the techniques of thiol-Sepharose chromatography and cDNA-Sepharose hybridisation has resulted in a system in which the transcription of the Friend virus proviral sequences with endogenous and E . coli polymerase can be examined . The results show that the percentage of Friend viral-specific sequences in RNA transcribed by E . coli RNA polymerase and by endogenous RNA polymerase in isolated nuclei are similar . The percentage of viral-specific sequences synthesized in isolated nuclei is similar to that found in Friend cell nuclear RNA.

Eur J Biochem, 1980 Mar, 104(2), 391 - 5
Cell-free synthesis of a flavoprotein containing the 8 alpha-(N3-histidyl)-riboflavin linkage; Hamm HH et al.; 6-Hydroxy-D-nicotine oxidase is an inducible flavorprotein of Arthrobacter oxidans in which one mole of FAD is bound covalently to the polypeptide chain . During cell-free translation of polysomes from nicotine-induced A . oxidans cells in the presence of an Escherichia coli (MRE 600) supernatant fraction, labelled FAD, leucine and histidine were incorporated into 6-hydroxy-D-nicotine oxidase in the same ratio found in the enzyme isolated from whole cells . This indicates that one mole FAD is covalently attached per mol of 6-hydroxy-D-nicotine oxidase synthesized in vitro . In the native enzyme the coenzyme molecule is bound via its 8 alpha-methyl group to the N-3 atom of a histidyl residue . From the translation products an aminoacyl-riboflavin was isolated and its identity with synthetic 8 alpha-(N3-histidyl)-riboflavin was shown.

Blut, 1980 Mar, 40(3), 197 - 208
{Oxygen-dependent influence of lipopolysaccharide endotoxin on polymorphonuclear leukocytes (author's transl)}; Eschenbach C et al.; In in vitro experiments the effect of bacterial endotoxin (Lipopolysaccharide E . coli O 26 :B 6) on the ingestion, NBT reduction, and the formation of cytoplasmic vacuoles of polymorphonuclear leukocytes in the atmosphere of 21 vol-% O2 and 99.9 vol-% N2, respectively, was tested . High concentrations of endotoxin in O2-atmosphere cause an inhibition of the functions and a stimulation of vacuole formation, N2 atmosphere shows these effects of endotoxin on the ingestion and vacuole formation, if at all, in a lesser degree . These results show that endotoxin in high concentrations possibly causes an auto-oxidation of the polymorphonuclear leukocytes . This interpretation of the results is in accord with findings of other authors.

Am J Epidemiol, 1980 Mar, 111(3), 347 - 55
Lack of person-to-person transmission of enterotoxigenic Escherichia coli despite close contact; Levine MM et al.; The scanty epidemiologic evidence available suggests that enterotoxigenic Escherichia coli (ETEC) are usually spread by contaminated food and water vehicles; little is known of the risk of secondary spread by contact transmission . Studies carried out in a 22-bed isolation Ward at the U . of Maryland Hospital gave the opportunity to determine whether individuals excreting ETEC, with and without diarrhea, would transmit the pathogen to controls living in close contact . In one combined study, seven volunteers who had ingested 10(8) virulent ETEC (strain H10407), were housed day and night for two weeks with eight other volunterrs participating in an intranasal attenuated influenza vaccine study . In a second study, four persons ingesting 10(8) ETEC (strain 214-4) lived with 13 who were inoculated with intranasal influenza vaccine . The individuals in the E . coli and influenza groups were randomly mixed in bedrooms and shared bathrooms, dining and recreation areas of the ward . Seven persons who ingested ETEC developed diarrhea; all 11 excreted the pathogen (10(7)-10(9) organisms/gm or ml of stool), and 10 had significant rises in anti-O or antitoxin antibody . In contrast, no influenza vaccinees, despite close sharing of facilities, developed diarrhea, excreted ETEC or had rises in antibody to E . coli antigens . These data suggest that ETEC are not readily transmitted to healthy adults by direct person-to-person contact . Precautions to prevent contamination of shared food sources would appear to be the most rational intervention to avoid secondary cases of ETEC diarrhea.

Lab Invest, 1980 Mar, 42(3), 310 - 7
The in vivo quantitation and kinetics of rabbit neutrophil leukocyte accumulation in the skin in response to chemotactic agents and Escherichia coli; Issekutz AC et al.; This report describes the in vivo quantitation of neutrophil accumulation at inflammatory sites in rabbits by employing 51Cr-labeled autologous rabbit blood neutrophils . These labeled neutrophils circulated with a half of 3.2 to 3.8 hours . They were found to localize with great specificity at skin sites injected intradermally with zymosan-activated plasma, synthetic chemotactic peptides (e.g., N-formyl methionyl leucyl phenylalanine), Escherichia coli-derived chemotactic factors, or whole E . coli . Contrary to reports utilizing in vitro assays, under in vivo conditions the synthetic chemotactic peptides caused significantly less neutrophil accululation than zymosan-aulation by high concentrations of N-formyl methionyl leucyl phenylalanine was observed . Kinetic studies of the accumulation of labeled leukocytes in the skin in response to intradermal injection of formalin-killed E . coli were performed . Nearly all of the leukocytes accumulated during the first 4 hours after E . coli injection with a peak rate of accumulation between 2 and 3 hours . Essentially no additional localization of leukocytes occurred at lesions which were 6, 8, or 24 hours old . These results demonstrate that 51Cr-labeled rabbit blood neutrophils can be utilized to quantitate the degree of neutrophil accumulation in inflammatory reactions as well as to study the hour by hour kinetics of this accumulation.

Proc Natl Acad Sci U S A, 1980 Mar, 77(3), 1389 - 93
Structurally unique basic protein coextracted with histones from calf thymus chromatin; Jenson JC et al.; A histone-like protein that is rich in alanine and lysine (protein AK) has been obtained in homogeneous form by high-resolution gel filtration of H2SO4 extracts of calf thymus chromatin . Protein AK: (i) migrates as a single band in polyacrylamide gel electrophoresis in both acetic acid/urea and sodium dodecyl sulfate; (ii) is a basic protein; (iii) lacks tryptophan; (iv) is not extracted from chromatin with 0.35 M NaCl; and (v) is not soluble in 0.75 M HClO4 . Protein AK is distinguished from the high-mobility group (HMG) proteins on the basis of these latter solubility characteristics and from the histones and protein A24 on the basis of amino acid composition and distribution of tryptic peptides in two-dimensional chromato-electrophoresis . In addition, protein AK is distinguished from the HMG proteins, the histones, and protein A24 on the basis of its mobility in two polyacrylamide gel electrophoresis systems . The amino acid composition of protein AK resembles that of HU, a basic DNA-binding protein found in Escherichia coli.

J Bacteriol, 1980 Mar, 141(3), 1428 - 31
Lysine decarboxylase mutants of Escherichia coli: evidence for two enzyme forms; Goldemberg SH; Mutants with reduced lysine decarboxylase activity were isolated from an Escherichia coli polyamine auxotroph . These mutants could not produce induced enzyme, showing only a very low level of an apparently constitutive form . Both enzyme forms could be demonstrated in the parental strain.

J Bacteriol, 1980 Mar, 141(3), 1375 - 85
Control of phycobiliprotein proteolysis and heterocyst differentiation in Anabaena; Wood NB et al.; Phycobiliprotein degradation can be initiated in cultures of the cyanobacterium Anabaena by removal of combined nitrogen from the medium . Certain strains of Anabaena differentiate cells specialized for aerobic nitrogen fixation (heterocysts) under such conditions . We describe here a procedure for the preparation of extracts from heterocysts or vegetative cells that contain an activity capable of degrading only the phycobiliproteins in a mixture of soluble Anabaena proteins in vitro . This activity increased under nitrogen starvation conditions or in ammonia-replete cultures treated with the glutamine synthetase inhibitor methionine sulfoximine . The increase in activity induced by nitrogen starvation was prevented by chloramphenicol or by carbon starvation . Under all these conditions, phycobiliprotein degradative activity assayed in vitro was correlated with the loss of phycobiliprotein absorbance in vivo . Finally, starvation of a met auxotroph of Anabaena for methionine (in the presence of ammonia) did not induce phycobiliprotein degradation in vivo or the increase in proteinase activity . Together with direct measurements of ppGpp, these results indicate that proteolysis in Anabaena is not controlled by compounds associated with the stringent response in Escherichia coli . Since the increase in proteinase activity appears to be regulated by the same variables that control heterocyst differentiation, the activity should provide a useful biochemical marker for the early events of differentiation.

J Bacteriol, 1980 Mar, 141(3), 1291 - 7
Beta-alanine synthesis in Escherichia coli; Cronan JE Jr; The enzyme, aspartate 1-decarboxylase (L-aspartate 1-carboxy-lyase; EC 4.1.1.15), that catalyzes the reaction aspartate leads to beta-alanine + CO2 was found in extracts of Escherichia coli . panD mutants of E . coli are defective in beta-alanine biosynthesis and lack aspartate 1-decarboxylase . Therefore, the enzyme functions in the biosynthesis of the beta-alanine moiety of pantothenate . The genetic lesion in these mutants is closely linked to the other pantothenate (pan) loci of E . coli K-12.

Mutat Res, 1980 Mar, 77(3), 197 - 208
Induction of prophage lambda by daunorubicin and derivatives correlation with antineoplastic activity; Anderson WA et al.; The antineoplastic drug daunorubicin and 15 other anthracyclines were tested for their ability to induce prophage lambda in Escherichia coli K12 . Prophage lambda induction by daunorubicin was obtained in excision-repair deficient uvr- bacteria at doses about 3-fold lower than in excision-repair proficient uvr+ cells; this suggests that some of the lesions produced in DNA by daunorubicin are subject to excision repair and may be adducts . Daunorubicin seems to be converted to active species capable of causing prophage inducing lesions in DNA by bacterial enzymes . The antineoplastic and prophage inducing potencies of the anthracyclines were compared in a blind test . These two parameters were correlated for two thirds of the compounds . Such a correlation supports the idea that the antineoplastic activity of the anthracyclines is a consequence of their capacity to damage DNA.

Proc Natl Acad Sci U S A, 1980 Mar, 77(3), 1491 - 5
Synthesis and maturation of lambda receptor in Escherichia coli K-12: in vivo and in vitro expression of gene lamB under lac promoter control; Marchal C et al.; The lambda receptor is an outer membrane protein from Escherichia coli K-12 lamB, its structural gene, is part of the maltose regulon . We have cloned this gene in a phage so that it is under the control of the lac promoter . The phage was devised in such a way that it can infect lamB mutants and that chromosomal lamB mutations can be transferred to it . In vivo, the lambda receptor is expressed under lac promoter control and is exported normally to the outer membrane, independently of the expression of the other genes of the maltose regulon . In vitro, DNA of the phage allows efficient synthesis of the lamB product . The protein--or pre-lambda-receptor--made in vitro contains an NH2-terminal sequence of about 25 amino acids not found in the lambda receptor . We have detected no inactivation of phage lambda by the pre-lambda-receptor . Conversion of the pre-lambda-receptor to a form that has the apparent molecular weight of the mature lambda receptor was achieved . A lamB mutation that blocks export in vivo also blocks conversion in vitro.

Proc Natl Acad Sci U S A, 1980 Mar, 77(3), 1412 - 6
Structural and functional analysis of cloned DNA containing genes responsible for branched-chain amino acid transport in Escherichia coli; Oxender DL et al.; The four genes encoding the components of the high-affinity branched-chain amino acid transport systems in Escherichia coli (livH, livG, livJ, and livK) have been cloned into lambda phage and subsequently into the plasmid vector pACYC184 . The presence of the four structural genes and their accompanying regulatory regions on the resultant plasmid, pOXI, was confirmed by genetic complementation and analysis and by transport studies carried out on the appropriate transformed mutant strains . When pOX1 DNA was used to direct an in vitro transcription/translation system, four major polypeptide products were produced . Immunoprecipitation with antibody directed against the LIV-binding protein identified the two leucine-binding proteins as products of in vitro synthesis . The binding proteins were produced in precursor forms and had molecular weights approximately 2500 higher than the processed, mature forms . A minicell-producing strain transformed with plasmid pOX1 produced the binding proteins in the processed form.

Afr J Med Med Sci, 1980 Mar-Jun, 9(1-2), 7 - 13
Neonatal ascites in Benin, Nigeria; Odita JC et al.; Seven cases of neonatal ascites are presented . The commonest cause is obstructive uropathy from posterior urethral valves which was present in four patients . Two infants had septicaemia and meconium peritonitis was found in the seventh case . Radiological evaluation often revealed the anatomic lesion . The mortality rate was 100%.

Res Vet Sci, 1980 Mar, 28(2), 217 - 22
Response of caeruloplasmin to Escherichia coli endotoxins and adrenal hormones in the domestic fowl; Curtis MJ et al.; The injection of chickens with Escherichia coli endotoxins immediately produced a 50 per cent rise in plasma caeruloplasmin activity which was attributed to the release of the protein from liver cell . This was followed by a fall in activity, which was probably due to a fall in activity, which was probably due to a stabilising effect of adrenocortical hormones on the cell membranes, and then by a five-fold increase . The results of experiments with cycloheximide, adrenocorticotrophin, beta-methasone and reserpine indicated that the third phase of the response reflected increased synthesis in the liver which was partly induced by adrenal hormones . It increased with the dose and was not elicited by the particulate nature of the toxin preparation or by its lipid and polysaccharide components.

Can J Microbiol, 1980 Mar, 26(3), 393 - 6
Characterization of an Escherichia coli mutant which utilizes glycerol in the absence of cyclic adenosine monophosphate; Fraser AD et al.; The aerobic catabolism of glycerol depends on the expression of the glpK operon specifying a glycerol kinase and the glpD operon specifying an sn-glycerol-3-phosphate (G3P) dehydrogenase . It has not been clearly established how the expression of these operons is dependent on adenosine 3',5'-cyclic monophosphate (cAMP) . We have isolated a promoterlike mutant (CA8306B) which, owing to a mutation in the glpK operon, can utilize glycerol in the absence of cAMP . Glycerol kinase and G3P dehydrogenase are inducible in CA8306B and its wild-type parent CA8000 . The induced level of glycerol kinase in CA8306B is 30% that of CA8000 and this level is increased fivefold by the addition of cAMP . However, the induced level of G3P dehydrogenase in CA8306B is similar to that of CA8000 and is unaffected by cAMP addition . These results suggest that the promotion of the glpK operon requires cAMP whereas the promotion of the glpD operon does not.

J Gen Microbiol, 1980 Mar, 117(1), 243 - 7
Transposition of Tn951 (Tnlac) and cointegrate formation are thermosensitive processes; Cornelis G; The frequency of transposition of Tnlac to pGC200, an IncFII R plasmid, increased during the storage of the host strain . This result is explained by the fact that the transpositional event is temperature-dependent: it occurred readily when the host strain was grown at 30 degrees C but it was nearly undetectable when the host strain was grown and kept at 37 degrees C . Fusions between two different plasmids carrying Tnlac with pGC200 were also thermosensitive, suggesting a relation between cointegrate formation and transposition . Lactose did not influence the frequency of transposition of Tnlac.

J Gen Microbiol, 1980 Mar, 117(1), 135 - 40
Adenine + thymine content of different genes located on the broad host range plasmid RP4; Burkardt HJ et al.; The genetic map of plasmid RP4 was correlated with its adenine+thymine (AT) map . For this purpose, RP4 DNA was digested with one or both of the restriction enzymes EcoRI and HindIII and the resulting linear RP4 molecules and fragments were partially denatured, examined in the electron microscope and their AT maps were determined using a computer program . From these AT maps the EcoRI and HindIII restriction sites were located on the AT map of RP4 . Since the positions of these restriction sites on the genetic map of RP4 are known, the maps could be compared . They revealed a high AT content for the Tn1 transposon and the kanamycin resistance gene . The tra-1 region is also distinguished by a sharply defined AT-rich region, whereas tra-2 and the tetracycline resistance gene have an AT content which is not distinctly different from the average AT content of RP4.

Biochem J, 1980 Mar 1, 185(3), 755 - 60
The preparation of calmodulins from barley (Hordeum sp.) and basidiomycete fungi; Grand RJ et al.; 1 . Calmodulin-like proteins were purified from the fruiting bodies of higher (basidiomycete) fungi and barley (Hordeum sp.) shoots . 2 . These calmodulins have electrophoretic mobilities on 10% (w/v) polyacrylamide gels at pH 8.3 in the presence of 6 M-urea and at pH 8.3 in the presence of 0.1% sodium dodecyl sulphate similar to that of bovine brain calmodulin . They interacted with rabbit skeletal-muscle troponin I in the presence of Ca2+ . 3 . Barley and fungal calmodulins activated myosin light-chain kinase and phosphodiesterase in the presence of Ca2+, although the amounts needed were at least an order of magnitude greater than is required to produce the same effect with mammalian calmodulin . 4 . Amino acid analyses indicated a number of differences from the mammalian protein, most notably the absence of trimethyl-lysine . 5 . By using 125I-labelled calmodulin, a small amount of calmodulin-binding protein was detected in homogenates of barley and fungi . 6 . No protein corresponding to calmodulin could be found in Escherichia coli or yeast, although a relatively high concentration of a protein that bound calmodulin was detected in E . coli by this technique.

Can J Physiol Pharmacol, 1980 Mar, 58(3), 281 - 6
Effects of phentolamine on hepatic PO2 in endotoxemia; Kaelin CR et al.; The effect of phentolamine, an alpha-adrenergic blocker, on hepatic oxygen supply, plasma glucose, and lactate, and survival in fasted male rats administered Echerichia coli endotoxin (25 mg/kg, ip) has been studied . Survival at 24 h was 8% in untreated endotoxic rats, 83% in rats receiving phentolamine (5 mg/kg, ip) and endotoxin, and 100% in phentolamine controls . Measurements during the initial 8 h postendotoxin recorded transiently lower systemic arterial pressure in the phentolamine-endotoxic rats . Arterial PO2 and increases of pH and heart rate were similar in both endotoxic groups . Lactacidemia, present by 4 h in untreated endotoxic rats, did not develop in the phentolamine group and plasma glucose was significantly higher at 8 h (98 +/- 2.5 vs . 77 +/- 5.6 mg%, mean +/- SE) . Mean hepatic PO2 at 6 h in phentolamine-endotoxic rats was 9.6 mmHg with 28% of the values below 5 mmHg . By contrast, the mean in untreated endotoxic rats was 1.9 mmHg with 88% of values below 5 mmHg . Phentolamine controls were stable over 8 h; mean hepatic PO2 was 17.7 mmHg . The differences in plasma glucose and lactate suggest protection of hepatic metabolism in phentolamine-treated endotoxic rats by prevention of excessive hepatic hypoxia.

Biokhimiia, 1980 Mar, 45(3), 483 - 91
{Properties of aminoglycoside-3'-phosphotransferases determined by kanamycin transposones Tn 601 and Tn 5}; Ganelin VL et al.; Aminoglycoside-3'-phosphotransferase I and II (APT-3'-I and APT-3'-II) has been purified to homogenity from the cells of E . coli containing the plasmids R6 and JR67, respectively . The purification procedure involved competitive affinity chromatography on neomycin-sepharose and gel-filtration on Sephadex G-100 . The specific activity of APT-3'-I with the substrates--lividomycin A, neomycin B, paromycin, ribostamycin, kanamycins A and B--are 4.3, 2.8, 2.1, 1.6, 0.9 and 0.8 mol/min . mg protein, respectively . The specific activity of APT-3'-II with the substrates--ribostamycin, paromycin, kanamycins A and B, neomycin B--are 8.0, 7.2, 4.0, 4.5 and 3.6, respectively . Mg2+ is required for the activity of both enzymes . Co2+, Zn2+ and Mn2+ are active in case of APT-3'-I; however, these cations are less active than Mg2+ . The pH-optimum of APT-3'-I and APT-3'-II is 7.0--7.5 . High ionic strength is required for the activity of both enzymes . The molecular weights of APT-3'-I and APT-3'-II are about 36 000 and 26 000, respectively . The amino acid composition of APT-3'-I and APT-3'-II was determined . Both enzymes contain tryptophane residues whose fluorescence intensity decreased when ATP, but not amino-glycoside antibiotics, is added . The interrelationship between the molecular weights of these enzymes and the sizes of the loops of transposones Tn 601 and Tn 5, encoding APT-3'-I and APT-3'-II, is discussed.

Eur J Biochem, 1980 Mar, 105(1), 25 - 31
A DNA-binding protein specific for the early replicated region of the chromosome obtained from Escherichia coli membrane fractions; Jacq A et al.; After extensive dialysis of Escherichia coli membranes treated with Triton X-100, three membrane proteins (A, B and B') with an affinity for DNA have been isolated and purified . They bind to either double-stranded or single-stranded DNA . A and B' proteins preferentially attach to DNA even in the presence of poly(uridylic acid) . Only protein B' can recognize some base sequence of DNA because pulse-labelled DNA made at the initiation of replication in a synchronized dnaC mutant has been selectively retained by the protein.

Eur J Biochem, 1980 Mar, 105(1), 109 - 16
Degradation of linear and circular DNA with gaps by the recBC enzyme of Escherichia coli . Effects of gap length and the presence of cell-free extracts; Prell A et al.; It is shown that circular PM2 DNA with two gaps of 13 nucleotides per molecule is degraded by purified recBC enzyme from Escherichia coli to acid-soluble material at a rate which is less than one tenth of the rate of solubilization of linear duplex DNA . Increasing the gap length in the circular DNA to 40-650 nucleotides does not affect the breakdown of the molecules by the recBC enzyme, nor does it change the proportions of the products formed (acid-soluble material, acid-insoluble fragments and non-degraded molecules) . On the other hand, terminal gaps in linear duplex DNA produced by limited digestion with either exonuclease III or lambda exonuclease significantly reduce the rate of the degradation by the recBC enzyme, particularly when the gaps exceed 100 nucleotides . The results suggest that the recBC enzyme does not cleave gaps in circular DNA at random positions, but possibly at the junction between single-stranded and duplex DNA or close to it . The degradation of gapped circular DNA by purified recBC enzyme was used to search for an inhibitor of the recBC enzyme in extracts from ultraviolet-irradiated cells . No such inhibitor has been observed but rather a weak stimulatory factor for the solubilization of gapped circular DNA by the recBC enzyme . Thus, the experimental system appears not to be suited as a test in vitro for an ultraviolet-induced inhibitor of the recBC enzyme which has been postulated to be produced in recA+ lexA+ cells of E . coli after ultraviolet irradiation.

Eur J Biochem, 1980 Mar, 105(1), 1 - 6
Isolation of a complex between the P protein of phage lambda and the dnaB protein of Escherichia coli; Klein A et al.; P protein of phage lambda and dnaB protein of Escherichia coli were isolated from (a) bacteria containing an inducible lambda P gene on a plasmid, and (b) phage-lambda-infected bacteria . P protein from both sources copurifies with part of the dnaB protein during four purification steps . A highly purified preparation contains the multimeric dnaB and the P protein in a complex as revealed by glycerol gradient centrifugation . The complex is composed of two major polypeptides . Their molecular weights of 52 000 and 26 000 are identical to those previously determined for the dnaB and P polypeptides, respectively . The complex contains a DNA-dependent ribonucleoside triphosphatase activity which can be inactivated by anti-dnaB globulin . Both the dnaB complementing and the ribonucleoside triphosphatase activities are partially masked by the P protein as shown by their stimulation following a treatment with sodium chloride and N-ethylmaleimide.

Am J Trop Med Hyg, 1980 Mar, 29(2), 246 - 53
Diarrhea in a non-hospitalized rural Salvadoran population: the role of enterotoxigenic Escherichia coli and rotavirus; Spencer HC et al.; To determine the role of rotavirus, enterotoxigenic Escherichia coli and enteropathogenic E . coli in diarrheal disease of non-hospitalized children and adults living in rural El Salvador, stool specimens were collected from 156 persons with diarrhea and 134 age- and sex-matched controls over a 1-year period . Enterotoxigenic Escherichia coli (ETEC) were isolated as frequently from controls (13.4%) as from diarrhea cases (12.2%) . Enteropathogenic E . coli were isolated from 13 cases (8.3%) and 10 (7.7%) controls . Rotavirus was demonstrated in only five of the 129 specimens from cases examined; the five persons infected were less than or equal to 3 years of age . No invasive E . coli were found . Serotyping of ETEC revealed serogroups of ETEC previously associated with enterotoxigenicity but was not helpful in separating infection from disease . The etiology of diarrhea in this rural, non-hospitalized population was complex . Isolation of a known pathogen did not prove etiology . The rotaviruses, which have been isolated frequently from hospitalized persons, were rare . Further laboratory and epidemiologic studies in such populations are needed to identify those factors that determine pathogenicity.

J Virol, 1980 Mar, 33(3), 927 - 35
Transcription of polyoma DNA by Escherichia coli RNA polymerase: influence of ionic strength on promoter selection; Dandolo L et al.; The influence of ionic strength on transcription of polyoma DNA by Escherichia coli RNA polymerase was investigated . At 0.15 M KCl, transcription was highly symmetrical and, due to the lack of reinitiation, a limited extent of RNA synthesis was observed . When the concentration of KCl was raised to 0.45 M, the affinity of the enzyme for its template, as well as its apparent affinity for ribonucleoside triphosphates, was reduced . Under optimal conditions, the rate and extent of RNA synthesis at 0.45 M KCl were greater than at 0.15 M KCl, and transcription was mostly asymmetric . Binding and initiation sites at both ionic strengths were identified; at 0.15 M KCl, transcription was initiated from two major sites, located at 0.99 and 0.06 map unit, whereas at 0.45 M KCl, a unique initiation site, at 0.99 map unit, was selected by RNA polymerase.

J Bacteriol, 1980 Mar, 141(3), 1424 - 7
Repair of x-ray-induced deoxyribonucleic acid single-strand breaks in xth mutants of Escherichia coli; Seeberg E et al.; An exonuclease III-deficient strain of Escherichia coli K-12, BW2001 (xthA11), was unable to perform rapid repair of X-ray-induced deoxyribonucleic acid single-strand breaks and appeared to have a defect in the priming of the 3'-termini necessary for initiation of repair synthesis at the breaks . This defect cannot be explained solely by the lack of exonuclease III activity, because other xth mutants tested, including a deletion mutant, repaired radiation-induced strand breaks at close to the normal rate.

Cell, 1980 Mar, 19(3), 795 - 805
The inverted repeats of Tn5 are functionally different; Rothstein SJ et al.; The inverted repeats of Tn5, which have identical restriction endonuclease cleavage patterns, have different functional properties . They differ with respect to RNA polymerase binding, full promotion of neomycin resistance, the polypeptides coded for by the repeats and their function in the transposition process . There is a week RNA polymerase binding site present in one repeat and not in the other which seems to be important for neomycin resistance . The two inverted repeats code for polypeptides of different molecular weights, with each repeat appearing to encode two polypeptides . The polypeptides from only one of the repeats of Tn5 appear to be absolutely required for Tn5 transposition.

J Biochem (Tokyo), 1980 Mar, 87(3), 825 - 30
2'-Deoxy-2'-azidoadenosine triphosphate and 2'-deoxy-2'-fluoroadenosine triphosphate as substrates and inhibitors for Escherichia coli DNA-dependent RNA polymerase; Ishihama A et al.; The effects of 2'-substitutions of ATP on the substrate and inhibitor properties for RNA synthesis were studied in the poly(dAT)-dependent reaction of Escherichia coli RNA polymerase . In the presence of UTP, 2'-deoxy-2'-azidoadenosine 5'-triphosphate (AZTP) was incorporated into an acid-insoluble fraction at one-tenth of the rate of ATP incorporation; it thus acts as a competitive inhibitor for poly(AU) synthesis . On the other hand, another ATP analog, 2'-deoxy-2'-fluoroadenosine 5'-triphosphate (AfTP), was co-polymerized with UTP into acid-insoluble materials at a rate less than 1% of that of ATP incorporation; in addition, it exerted a strong but mixed-type inhibition on poly(AU) synthesis . Different modes of action of the two ATP analogs are discussed in connection with the specificity of substrate recognition by RNA polymerase.

J Bacteriol, 1980 Mar, 141(3), 1457 - 9
Thermal modulation of fatty acid synthesis in Escherichia coli does not involve de novo enzyme synthesis; Garwin JL et al.; An increased ratio of unsaturated to saturated fatty acids was synthesized within 30 s after shift of Escherichia coli K-12 from 42 degrees C to 24 degrees C . This was more than 10-fold faster than the induction of beta-galactosidase . Inhibition of ribonucleic acid or protein synthesis had no effect on the response of fatty acid synthesis to temperature shift.

J Bacteriol, 1980 Mar, 141(3), 1098 - 108
Synthesis and activity of ribonucleic acid polymerase in Escherichia coli; Shepherd NS et al.; The amounts of ribonucleic acid (RNA) polymerase (beta' subunits) and ribosomes (RNA), and the fraction of RNA polymerase actively engaged in transcription, were measured in Escherichia coli B/r as a function of growth rate . By an improved method of quantitating protein bands on electrophoresis gels, the systematic error and reproducibility of the RNA polymerase determination were estimated to be less than 15 and 6%, respectively . For a threefold increase in growth rate, the fractional synthesis of polymerase (relative to protein) increased 1.5-fold, whereas the fractional synthesis of ribosomal protein increased 2.2-fold . The decrease in the amount of RNA polymerase per ribosome with increasing growth rate is interpreted as an expression of the control of the transcriptional read-through from the genes for ribosomal protein, rplJ,L, to the adjacent genes for RNA polymerase subunits, rpoB,C . The number of active RNA polymerase molecules was determined from the synthesis rates of stable and messenger RNA and the known RNA chain growth rates . Comparison of active and total RNA polymerase indicates that the fraction of active enzyme increases from 20 to 30% in the range of growth rates between 0.6 and 2.0 doublings per hour . Possible causes for the inactive enzyme are discussed.

Chem Biol Interact, 1980 Mar, 29(3), 327 - 33
Inhibitory studies of DNA, RNA and protein synthesis in Escherichia coli by platinum containing complexes; Kohl HH et al.; Previous studies have shown various platinum containing compounds to be effective anti-tumor agents in man and animals . Many of these compounds have also been shown to be effective inhibitors of bacterial DNA, RNA and protein synthesis . Data is presented here which compares the inhibitory effectiveness of a number of recently synthesized platinum compounds toward the inhibition of the synthesis of DNA, RNA and protein in Escherichia coli . We also compared the effectiveness of these compounds toward the inhibition of bacterial growth . Some of these new derivatives appear to be nearly 3-fold more potent than the more thoroughly studied cis-diamminedichloroplatinum(II) (cis-PDD) and trans-diamminedichloroplatinum(II) (trans-PDD).

J Gen Microbiol, 1980 Mar, 117(1), 33 - 45
Complementation in vitro between guaB mutants of Escherichia coli K12; Gilbert HJ et al.; Guanine auxotrophs of Escherichia coli were isolated following mutagenesis by N-methyl-N'-nitro-N-nitrosoguanidine or ethyl methanesulphonate . The mutants were classified according to growth properties and absence of IMP dehydrogenase or GMP synthetase activity . Mutations in guaB (IMP dehydrogenase-less) were analysed by reversion and suppression tests; all were of the base substitution missense type except for one possible frameshift and one polar nonsense mutation . GuaB mutants were examined for protein (CRM) that cross-reacts with monospecific antibodies to IMP dehydrogenase; approximately half were CRM+ . Enzyme complementation in vitro was detected in mixed denatured and renatured cell-free extracts of any CRM+ guaB mutant and PL1138 (guaB105, CRM+); CRM- mutants did not complement . GuaB105 maps distal to all other guaB mutations except guaB86 (CRM-) . Two hybrid enzymes produced by complementation were less stable to heat than native IMP dehydrogenase, although kinetic constants were similar . These observations indicate interallelic complementation between guaB mutants and are consistent with the demonstration of identical subunits for IMP dehydrogenase (Gilbert et al., 1979) . Only the subunits supplied by PL1138 are catalytically active in the hybrid enzymes suggesting that this mutant may produce a repairable polypeptide whereas the enzymes of complementing mutants may be defective at the active site.

Biochim Biophys Acta, 1980 Feb 29, 606(2), 387 - 9
Hybridization analysis of the methylated bases of Escherichia coli DNA; Quint A et al.; The 5-methylcytosine residues of Escherichia coli DNA are randomly dispersed along the genome . Hybridization data indicate that these methyl moieties are transcribed at the same frequency as the total DNA . These results suggest that DNA methylation probably does not play a role in gene expression in bacteria.

Biochim Biophys Acta, 1980 Feb 29, 606(2), 347 - 52
Beta-selenaproline as competitive inhibitor of proline activation; Busiello V et al.; Beta-Selenaproline, a proline analog having the beta-methylene group substituted by a selenium atom, has been tested in ATP-PPi exchange reaction catalyzed by either Escherichia coli or rat liver aminoacyl-tRNA synthetases . It has been shown that with both enzymatic systems beta-selenaproline does not give rise to ATP-PPi exchange, but specifically inhibits proline activation . The inhibition is of fully competitive type and the Ki values, lower than the Km values for proline, show that beta-selenaproline binds to the synthetases with high affinity . The inability to form the complex with AMP, taking into account also the behavior of gamma-selenaproline and other proline analogs, has been ascribed to the presence of the selenium atom in the beta-position.

Biochim Biophys Acta, 1980 Feb 29, 606(2), 353 - 61
Effects of polyethylene glycol on reverse transcriptase and other polymerase activities; Chan EW et al.; Polyethylene glycol enhances reverse transcription, augmenting both the rate and duration of polymerization . The effective mean molecular weight of polyethylene glycol is 6000 and the optimal concentration is 12% (w/w) . Polyethylene glycol is effective on the reverse transcriptase reaction of all ten type B, C, and D viruses tested under a variety of exogenous, endogenous, and reconstitution assay systems, including the highly efficient conditions involving calf thymus DNA oligonucleotide primers . By three methods of synthesis, polyethylene glycol increased the yields of complementary {3H}DNA by a factor of 1.8--6.5 . Polyethylene glycol does not alter the divalent cation requirements of the specificities of the enzyme . Complementary {3H}DNAs made in the presence of polyethylene glycol are indistinguishable in terms of size and sequence complementarity from those made in the absence of the polymer . The stimulatory effect was partly due to the ability of polyethylene glycol to stabilize reverse transcriptase . Preliminary tests indicate that polyethylene glycol also stimulates other nucleotide polymerases, such as the DNA-dependent DNA and RNA polymerases of Escherichia coli and the terminal transferase of calf thymus.

Biochim Biophys Acta, 1980 Feb 29, 606(2), 262 - 73
Structural changes in the glutamine-chargeable Escherichia coli transfer RNA-Trp produced by chemical modification with sodium bisulfite; Iwata K et al.; Glutamine-mischargeable tRNA produced by sodium bisulfite-treated Escherichia coli tRNA-Trp was isolated by dihydroxyboryl-cellulose affinity column chromatography . This tRNA was shown to have dual specificity tryptophan and glutamine, and, when charged with either amino acid, bound to ribosomes in response to the non-sense codon UAG but not in response to the tryptophan codon UGG . The results were consistent with the reported properties of Su+7 tRNA . The bisulfite-treated tRNA-Trp migrated as two bands during polyacrylamide gel electrophoresis . The faster moving band (band I) coincided with that of untreated tRNA-Trp . The slower moving band (band II) coincided with the glutamine-chargeable tRNA-Trp . Su+7 tRNA behaved like band II tRNA upon gel electrophoresis . Nucleotide sequence analysis showed that a cytidine-uridine transition occurred at the 1st or the 2n position of the anitcodon of band II tRNA . Band I and band II tRNAs differed from each other in their thermal melting profiles . It is suggested that the single base change in the anticodon is responsible for the altered conformation of band II tRNA.

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