Escherichia coli

Biochim Biophys Acta, 1977 Feb 16, 474(4), 629 - 38
Interaction of DNA with DNA binding proteins . II . Displacement of Escherichia coli DNA unwinding protein and the condensed structure of DNA complexed with protein HD; Zentgraf H et al.; Three DNA binding proteins from Escherichia coli cells have been complexed with single-stranded phage fd DNA . Electron microscopy reveals granular substructures in the complexes formed with protein HD . In complexes of DNA unwinding protein with fd DNA both protein HD and phage-coded gene 5 protein partially displace the unwinding protein which results in the formation of structures characteristic for the DNA complexes formed with either protein HD or gene 5 protein alone . Combination of protein HD with double-stranded phage T7 DNA leads to a progressive folding and condensing of the genome . The structures observed are discussed in relation to current concepts of the packing of DNA in protein complexes.

Biochim Biophys Acta, 1977 Feb 16, 474(4), 609 - 18
A specific polyadenylase from Escherichia coli K12; Antoniades D et al.; A polyadenylase, degrading specifically poly(A) sequences was isolated from Escherichia coli K12 . The enzyme was purified about 850 times to practically electrophoretic homogeneity . It was free of poly(A) polymerase activity, as well as of the well known E . coli RNAases I and II . It is stimulated by bivalent cations like Mg2+ and Mn2+ and splits poly(A) to 3'-AMP and therefore it can be considered as an exonuclease . The enzyme does not degrade any other ribohomopolymer or RNA.

Mol Gen Genet, 1977 Feb 15, 150(3), 325 - 8
Relative order of glg mutations affecting glycogen biosynthesis in Escherichia coli K12; Latil-Damotte M et al.; Mutations affecting the glycogen biosynthesis in E . coli can be mapped at three different loci, glg A, glg B and glg C lying between asd and mal A . Transduction tests suggest the following order for the genes in this region: mal A--glg A--glg C--glg B--asd.

Mol Gen Genet, 1977 Feb 15, 150(3), 317 - 24
Escape synthesis of RNA polymerase subunits and termination factor rho following induction of prophage lambda in Escherichia coli; Nakamura Y et al.; Synthesis of RNA polymerase subunits and of transcription termination factor p was studied after thermoinduction of prophage lambdac1857 located at several unusual sites on the chromosome of Escherichia coli . When a lysogen carrying the prophage at the bfe gene was induced at 42 degrees C, the rate of synthesis of core polymerase subunits (alpha, beta and beta') rapidly decreased, followed by a marked increase after about 10 min . The latter increase was observed specifically in the "bfe lysogen" and not in any of the other lysogens tested . Similarly, the rate of synthesis of p factor increased appreciably in the induced ilv lysogen carrying the prophage at the ilv gene, and possibly in the bfe lysogen as well, but not in other lysogens examined . Taken together with other evidence, these results suggest that the enhanced syntheses of beta and beta' subunits of RNA polymerase and of p factor observerd represent "escape synthesis", resulting from the close linkage of the prophage genome to the respective structural genes . In contrast, omega factor synthesis was stimulated upon induction of any of the lysogens used without respect to the site of prophage location, suggesting the involvement of an entirely different mechanism.

Mol Gen Genet, 1977 Feb 15, 150(3), 285 - 92
Re-examination of F plasmid replication in a dnaC mutant of Escherichia coli; Van Brunt J et al.; The replication of an F' plasmid in a dnaC mutant, thermolabile for initiation of chromosomal replication, has been re-examined using a novel DNA-DNA annealing assay . Plasmid replication ceases rapidly at non-permissive conditions, consistent with a direct role for the dnaC product in the replication of F.

Mol Gen Genet, 1977 Feb 15, 150(3), 249 - 55
ppGpp cycle in Escherichia coli; Kari C et al.; Kinetics of accumulation and degradation of ppGpp and pppGpp were analysed in spoT+ and spoT strains of Escherichia coli . The experimental data in this paper indicate that on degradation ppGpp is not converted to pppGpp but instead is converted to GDP which is in turn phosphorylated to GTP . In addition the data are consistent with the idea the pppGpp is a direct precursor of ppGpp . We propose that ppGpp is metabolised according to the following pathway: GTP-pppGpp--ppGpp--GDP--GTP, which we call the ppGpp cycle . Coupled with the observations in spot strains we assume that ppGpp blocks its own synthesis by inhibiting the synthesis of pppGpp but not the interconversion of the two nucleotides.

Mol Gen Genet, 1977 Feb 15, 150(3), 237 - 48
Induction of protein X in Escherichia coli; Little JW et al.; Certain treatments that damage DNA and/or inhibit replication in E . coli have been reported to induce synthesis of a new protein, termed protein X, in recA+ lexA+ strains . We have examined some of the treatments that might induce protein X and we have, in particular, tested the hypothesis of Gudas and Pardee (1975) that DNA degradation products play an essential role in the induction process . We confirmed that UV irradiation, nalidixic acid treatment, or thymine starvation result in protein X synthesis in wild type strains . However, we found that UV irradiation, unlike nalidixic acid, also induced protein X in recB strains, in which little DNA degradation occurs . Furthermore, we found that the presence of DNA fragments resulting from host-controlled restriction of phage lambda DNA did not affect protein X synthesis . We conclude that no causal relationship exists between the production of DNA fragments and induction of protein X . The presence of the plasmid R46, which confers enhanced mutagenesis and UV resistance on its host, did not affect protein X synthesis . Growth in the presence of 5-bromouracil, which does not result in production of degradation fragments, resulted eventually in a low rate of protein X synthesis . In dnaA mutants, deficient in the initiation of new rounds of replication, UV irradiation induced protein X, again unlike nalidixic acid . Thus, the inhibition of active replication forks is not an essential requirement for protein X induction.

Eur J Biochem, 1977 Feb 15, 73(1), 33 - 8
Simple isolation method and assay for T4 DNA ligase and characterization of the purified enzyme; Knopf KW; A method for the isolation of T4-amber-N82-induced DNA ligase is described which results in a nearly homogeneous enzyme preparation after two column chromatographic steps . The enzyme is detected during the purification by its ability to form a stable acid-precipitable enzyme-adenylate complex . Some properties of the assay, such as the effect of salt, temperature and incubation time, are presented . The isolated enzyme and its adenylate complex are characterized by acrylamide gel electrophoresis under native and denaturing conditions, as well as by isoelectric focusing . The purified enzyme exhibits a molecular weight of approximatel 60000 . Isoelectric focusing yields at least 5 protein components, which are able to form an enzyme-adenylate complex . The main activity possesses a p1 of 6 . The enzyme preparation is capable of repairing T5+ DNA known to contain about 4 or 5 single-strand breaks, to circularize lambda DNA and to join Hind111 and EcoR1 fragments.

Eur J Biochem, 1977 Feb 15, 73(1), 297 - 306
Processing by ribonuclease II of the tRNATyr precursor of Escherichia coli synthesized in vitro; Kitamura N et al.; The tRNATyr precursor molecule, synthesized from phi 80 psu3+ DNA (containing a single tRNA gene) by DNA-dependent RNA polymerase and q factor, was about 205 nucleotides long . The main product of its digestion with a ribonuclease tii preparation from Escherichia coli showed the same electrophoretic mobility as tRNAtyr precursor isolated in vivo and was found to be identical to it when analysed using fingerprint techniques . This intermediate precursor synthesized in vitro was converted further by processing with ribonuclease P into an RNA identical size to mature tRNATyr . It was concluded that the initiation of transcription of the tRNATyr gene in vitro occurs at the same site as that of transcription in vivo and a termination occurs at about 80 nucleotides beyond the CCA end of tRNATyr.

Eur J Biochem, 1977 Feb 15, 73(1), 179 - 84
Transcription of double-stranded RNA by Escherichia coli DNA-dependent RNA polymerase; Sugiura M et al.; Double-stranded RNA of some virus genomes can be used as template for the DNA-dependent RNA polymerase purified from Escherichia coli . The RNA synthesis requires all four nucleoside triphosphates and manganese ions and is dependent on the presence of sigma subunit . The reaction is inhibited by rifampicin, streptolydigin and ethidium bromide, but not by DNase and actinomycin D which does not bind to double-stranded RNA . The template activity of double-stranded RNA from various viruses is different in each case . The order of template efficiency is Penicillum chrysogenum virus greater than cytoplasmic polyhedrosis virus greater than rice dwarf virus greater than reovirus . The product obtained using cytoplasmic polyhedrosis virus double-stranded RNA as template is single-stranded and hybridizes specifically to the denatured template RNA . One of the major 5'-starting nucleotide sequences of the product RNA is pppA-A-Y-- . These results indicate that transcription in vitro of double-stranded RNA by E . Coli RNA polymerase is initiated at specific sites on the template.

Int J Cancer, 1977 Feb 15, 19(2), 236 - 9
Polyoma genome transcription in transformed mouse cells growing in culture and as tumors in syngeneic mice; Grady LJ et al.; The strands of the polyoma genome coding for early and late viral RNA were separated by means of asymmetric cRNA synthesized under high salt conditions by Escherichia coli RNA polymerase . Each strand was then employed in RNA-DNA hybridization experiments to determine the degree to which it is transcribed in transformed cells under several conditions . Except for a concanavalin-A-selected revertant, approximately one-quarter of the early strand was expressed in all of the situations investigated . In contrast, while no significant late strand transcription was detected in transformed cells in culture, the tumors induced by these cells contained transcripts complementary to about 12% of this strand . The results are discussed in terms of current knowledge of the amount of the virus genome required to transform cells.

Biochem J, 1977 Feb 15, 162(2), 309 - 20
Transport of galactose, glucose and their molecular analogues by Escherichia coli K12; Henderson PJ et al.; 1 . Strains of Escherichia coli K12 were made that are unable to assimilate glucose by the phosphotransferase system, since they lack the glucose-specific components specified by the genes ptsG and ptsM . 2 . Derivative organisms lacking the methyl galactoside or galactose-specific transport system were examined for their ability to transport galactose, d-fucose, methyl beta-D-galactoside, glucose, 2-deoxy-D-glucose and methyl alpha-D-glucoside . 3 . Galactose, glucose and to a lesser extent fucose are substrates for both transport systems . 4 . 2-Deoxyglucose is transported on the galactose-specific but not the methyl galactoside system . 5 . The ability of sugars to elicit anaerobic proton transport is associated with the galactose-specific, but not with the methyl galactoside transport activity . Hence a chemiosmotic mechanism of energization is likely to apply to the former but not to the latter . Alternatively the methyl galactoside system may be switched off under certain conditions, which would indicate a novel regulatory mechanism . 6 . Details of the procedure for the derivation of strains may be obtained from the authors, and have been deposited as Supplementary Publication SUP 50074 (8 pages at the) British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem . J . (1977), 161,1.

Eur J Biochem, 1977 Feb 15, 73(1), 115 - 24
Detergent-resistant phospholipase A of Escherichia coli K-12 . Purification and properties; Nishijima M et al.; Detergent-resistant phospholipase A, which is tightly bound to the outer membranes of Escherichia coli K-12 cells, was purified approximately 2000-fold to near homogeneity by solubilization with sodium dodecylsulfate and butan-1-ol, acid precipitation, acetone fractionation and column chromatographies on Sephadex G-100 in the presence of sodium dodecylsulfate and on DEAE-cellulose in the presence of Triton X-100 . The final preparation showed a single band in the sodium dodecylsulfate gel system . The enzyme hydrolyzes both the 1-acyl and 2-acyl chains of phosphatidylethanolamine or phosphatidylcholine . It also attacks 1-acyl and 2-acylglycerylphosphorylethanolamine . Thus, this enzyme shows not only phospholipase A1 and lysophospholipase L1 activities but also phospholipase A2 and lysophospholipase L2 activities . The enzyme lost its activity completely on incubation at 80 degrees C for 5 min at either pH 6.4 or pH 8.0 . It was stable in 0.5% sodium dodecylsulfate at below 40 degrees C . The enzyme was inactivated on incubation for 5 min at 90 degrees C in 1% sodium dodecylsulfate/1% 2-mercaptoethanol/4 M urea . The native and inactivated enzymes showed different protein bands with RF values corresponding to Mr 21 000 and Mr 28 000 respectively, in a sodium dodecylsulfate gel system . Triton X-100 seemed to protect the enzyme from inactivation . The purified enzyme was fully active on phosphatidylethanolamine in the presence of 0.0002% or 0.05% Triton X-100 . The enzyme requires Ca2+ . From its properties this enzyme seems to be identical with the enzyme purified from crude extracts of Escherichia coli B by Scandella and Kornberg . However, it differs from the latter in its positional specificity and susceptibility to sodium dodecylsulfate . Possible explanation of the difference of positional specificity of the two preparations is also described.

Biochim Biophys Acta, 1977 Feb 14, 465(1), 118 - 30
Unmasking of an essential thiol during function of the membrane bound enzyme II of the phosphoenolpyruvate glucose phosphotransferase system of Escherichia coli; Haguenauer-Tsapis R et al.; The addition of N-ethylmaleimide (MalNEt), or of fluoro dinitrobenzene to a suspension of Escherichia coli during the phosphorylating uptake of methyl-alpha-D-glucopyranoside (Me-Glc), a glucose analog, stops uptake and phosphorylation and causes the loss of previously accumulated sugar and of its phosphate ester . After removal of the reagents, the phosphotransferase system remains irreversibly inactive . Pretreatment of the bacteria with the same reagents under the same conditions of concentration, pH, temperature and for the same length of time causes very little inactivation . Mercuric chloride, a reversible inactivator, prevents the phosphotransferase system from reacting simultaneously with MaINEt or with fluorodinitrobenzene . This protection strongly suggests that all three reagents react with the same site, presumably an -SH group . The change which makes this site available to the reagents depends on the phosphorylative uptake of Me-Glc . Preload of the cells and efflux of Me-Glc do not achieve the same change . The rate of inactivation is directly proportional to the rate of phosphorylative uptake . When the Km of phosphorylative uptake is modified by an uncoupling agent, the substrate concentration allowing half maximal rate of inactivation by MaINEt changes accordingly . The reactive sites of the phosphotransferase system can also be made accessible to the -SH group reagents by fluoride inhibition of phosphoenolpyruvate synthesis . This suggests that the inactivator resistent form is an "energized form" of the enzyme . The unmasking of the reactive site is not due to a change in transmembrane penetration of the reagents since incubation of toluene treated cells with MaINEt in the presence of phosphoenolpyruvate fails to inactivate the phosphotransferase activity, while incubation with MaINEt plus Me-Glc causes fast inactivation.

J Biol Chem, 1977 Feb 10, 252(3), 1002 - 6
Aminoacyl adenylate, a normal intermediate or a dead end in aminoacylation of transfer ribonucleic acid; Lagerkvist U et al.; The shape of the time curve for the aminoacylation of tRNA has been investigated using five different amino acid:tRNA ligases . Four of these enzymes showed a lag in the time curve during the early phase of the first catalytic turnover of the enzyme . In each case, the lag period could be abolished by preincubating the ligase with amino acid, ATP, and Mg2+ under conditions known to give an aminoacyl adenylate-enzyme complex . With all five ligases the steady state rate of transfer from the preformed aminoacyl-adenylate complex to tRNA was approximately the same as that of the overall reaction.

J Biol Chem, 1977 Feb 10, 252(3), 814 - 9
Alteration of the kinetic parameters for aminoacylation of Escherichia coli formylmethionine transfer RNA by modification of an anticodon base; Schulman LH et al.; Treatment of Escherichia coli formylmethionine tRNA with 2 M sodium bisulfite, pH 7.0, in 10 mM MgCl2 at 25 degrees results in formation of uridine/bisulfite adducts at U18 in the dihydrouridine loop, U37 in the anticodon, and U48 in the variable loop . Two products, corresponding to the two diastereoisomers of 5,6-dihydrouridine-6-sulfonate, are formed at each reactive site in the tRNA . Although none of the modifications cause complete loss of methionine acceptor activity, the modified tRNA is amino-acylated at a reduced rate and has a decreased affinity for E . coli methionyl-tRNA synthetase . Aminoacylation of {35S}bisulfite-labeled tRNAfMet with a limiting amount of purified enzyme followed by separation of the acylated and unacylated molecules and structural analysis has shown that the presence of a specific diastereoisomer of the uridine/bisulfite adduct in the anticodon base U37 alters the kinetic parameters for aminoacylation of tRNAfMet.

Biochim Biophys Acta, 1977 Feb 9, 480(2), 479 - 88
Studies on aspartase . IV . Reversible denaturation of Escherichia coli aspartase; Tokushige M et al.; Aspartase (L-aspartate ammonia lyase, EC 4.3.1.1) of Escherichia coli, denatured in 4 M guanidine-HCl, was renatured in vitro by simple dilution with a concomitant restoration of the activity . While the native enzyme exhibited a marked negative Cotton effect centered at 233 +/- 1 nm in optical rotatory dispersion, the enzyme denatured in 4 M guanidine-HCl retained little optical activity . Upon dilution of the denatured enzyme, however, more than 90% of the ordered structure was recovered in 1 min, while the restoration of the activity proceeded much more slowly . Estimation of molecular weights by gel permeation chromatography indicated that the tetrameric enzyme is subject to reversible dissociation into monomeric subunits under the experimental conditions . Various environmental factors such as temperature, pH and protein concentration exhibited profound influence on the rate and extent of the reactivation . In order to examine the correlation between the restoration of the activity and the quaternary structure, electron microscopic inspection of the kinetic processes of reversible denaturation was attempted . Upon dilution of the denatured enzyme at 4 degrees C, neither the activity nor tetrameric images were detected over several min . Upon the temperature shift up to 25 degrees C, however, the activity regain was rapidly proceeded concomitant with the appearance of tetrameric molecules . These results are compatible with the possibility that the subunit assembly is an essential prerequisite, thought not sufficient, for enzyme activity.

Biochim Biophys Acta, 1977 Feb 7, 459(2), 225 - 40
Energy transduction in Escherichia coli . The effect of chaotropic agents on energy coupling in everted membrane vesicles from aerobic and anaerobic cultures; Hasan SM et al.; 1 . The transduction of energy from the oxidation of substrates by the electron transport chain or from the hydrolysis of ATP by the Mg2+-ATPase was measured in everted membrane vesicles of Escherichia coli using the energy-dependent quenching of quinacrine fluorescence and the active transport of calcium . 2 . Treatment of everted membranes derived from a wild-type strain with the chaotropic agents guanidine-HC1 and urea caused a loss of energy-linked functions and an increase in the permeability of the membrane to protons, as measured by the loss of respiratory-linked proton uptake . 3 . The coupling of energy to the quenching of quinacrine fluorescence and calcium transport could be restored by treatment of the membranes with N,N'-dicyclohyexylcarbodiimide . 4 . Chaotrope-treated membranes were found to lack Mg2+-ATPase activity . Binding of crude soluble Mg2+-ATPase to treated membranes restored energy-linked functions . 5 . Membranes prepared from a wild-type strain grown under anaerobic conditions in the presence of nitrate retained respiration-linked quenching of quinacrine fluorescence and active transport of calcium after treatment with chaotropic agents . 6 . Everted membrane vesicles prepared from an Mg2+-ATPase deficient strain lacked respiratory-driven functions when the cells were grown aerobically but were not distinguishable from membranes of the wild-type when both were grown under anaerobic conditions in the presence of nitrate . 7 . It is concluded (a) that chaotropic agents solubilize a portion of the Mg2+-ATPase, causing an increase in the permeability of the membrane to protons and (b) that growth under anaerobic conditions in the presence of nitrate prevents the increase in proton permeability caused by genetic or chemical removal of the catalytic portion of the Mg2+-ATPase.

Mol Cell Biochem, 1977 Feb 4, 14(1-3), 59 - 65
Specific features of the structural organization of the mitochondrial genome in rat liver; Shugalii AV et al.; The nature of intramolecular heterogeneity of mtDNA in the liver of white rats has been studied . The peculiarities of the melting curve, and the possibility of DNA fractionation of nucleotide compounds with hydroxylapatite (HA) column chromatography has shown the presence of sequences differing in the mean nucleotide content . A section of about 350 pairs in size repeated four times was found in the reassociation of most thermolabile fraction with a mean composition of 28% GC . These sections are well seen on the denaturation map of the recorded molecules formed in the range of temperature transition 'helix-coil' . The distance between the centers of fusible sections (in percentage of total length) is 32.5, 32, 14.0 and 21.5.

Mol Cell Biochem, 1977 Feb 4, 14(1-3), 47 - 54
The genetic system of kinetoplasts in trypanosomatides; Zaitseva GN et al.; In the present report, the genetic system of Crithidia oncopelti kinetoplast is used as a model for investigation of kinetoplast DNA (kDNA) structure, its transcription, protein synthesizing apparatus of the kinetoplast and the protein synthesis controlled genetically by kDNA . It was shown that kDNA of C . oncopelti can be isolated from cells or from kinetoplast fraction in the form of a network complex structure consisting of a lot of circular molecules . These minicircles have a contour length of about 0.83 micronm and molecular weight of 1.6 X 10(6) . The kDNA was demonstrated to be of higher AT content type than nuclear DNA . Besides, kDNA is characterized by a lesser degree of clustering of pyrimidines as compared with the nuclear one . The isolated kinetoplasts of C . oncopelti were shown to exhibit activity of DNA dependent RNA polymerase . The effect of some antibiotics and intercalating substances on RNA synthesis in kinetoplasts and mitochondria appears to be identical . Kinetoplasts of C . oncopelti have their own protein synthesizing system, whose components (ribosomes, rRNA, proteins, factors of incorporation) differ from those of the cytoplasm . Inhibition of translation by some antibiotics and of transcription by acriflavin allowed the suggestion that several proteins of kinetoplast ribosomes may be synthesized within this organoid . It was shown then that kDNA may be involved in the formation of the protein synthesizing apparatus in the kinetoplast.

Mol Cell Biochem, 1977 Feb 4, 14(1-3), 37 - 45
The character of protein-nucleic interaction in relation to the mtDNA-membrane complex; Kazakova TB et al.; Specific sites that interact with structural proteins of the mitochondrial inner membrane were found in mitochondrial DNA (mtDNA) of rat liver . Analysis of the isolated DNA fragments revealed their capacity to form a complex with membrane proteins in vitro and allowed the detection of a protein with a molecular weight 40,000 . The size of the fragments was found to be 12-18 nucleotide pairs with an average molecular weight 10,000 MtDNA sites recognized by membrane protein proved to be quite unique in having a secondary structure, a high content of AT sequences (82%) and oligopyrimidine blocks . It was shown that the light mtDNA strand, rich in adenine, is 60% more active in the binding with membrane mitochondria than the heavy one.

Mol Cell Biochem, 1977 Feb 4, 14(1-3), 31 - 6
The structure of animal mitochondrial DNA (base composition, pyrimidine clusters, character of methylation); Vanyushin BF et al.; Base composition, content of pyrimidine isopliths and the degree of methylation of mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) from various vertebrates and protozoon Crithidia oncopelti have been studied . MtDNAs from mammals (ox, rat) do not differ in fact in the GC content from the respective nDNA . The GC content in mtDNA from fishes (sheat fish) and birds (duck, chicken) is 1.5-2.5 mole % higher than in the respective nDNA . Kinetoplast DNA (kDNA) from Crithidia oncopelti (GC = 42.9 mole %) differs significantly in base composition from nDNA (GC = 51.3 mole %) . All the mtDNA and kDNA studied differ from the respective nDNA by a lower degree of pyrimidine clustering . The amount of mono and dipyrimidine fragments in mtDNA is more than 30 mole %, whereas in nDNA it does not exceed 23 mole % . The quantity of long pyrimidine clusters (hexa and others) is 2-4 times lower in mtDNA than in nDNA . The lower degree of clustering of pyrimidine nucleotides seems to be a specific feature of all the mtDNA studied . This may be indicative of common traits in the organization and origin of mtDNA . All mtDNA of vertebrates contain 5-methylcytosine as a 'minor' base (1.5- 3.15 mole %) and surpass by 1.5-2 times the respective nDNA in the methylation degree . It has been found that in animals mtDNA is species specific as far as the 5-methyl-cytosine content is concerned . In mitochondria and nuclei of rat liver certain DNA methylase activity has been detected, which provides in vitro the methylation of cytosine residues both in homologous DNA and various heterologous DNAs . The specificity of methylation in vitro of cytosine residues in the same heterologous DNA from E . coli B varies with the source of enzymes . The mitochondrial enzyme methylates cytosine as the lone monopyrimidine residue, whereas the nuclear enzyme methylase cytosine in the di- and tripyrimidine fragments.

Arch Microbiol, 1977 Feb 4, 112(1), 103 - 7
Alterations of alkaline phosphatase activity during adaptation of Escherichia coli to phosphite and hypophosphite; Lauwers AM et al.; When Escherichia coli cells were grown in media containing either phosphite or hypophosphite as the sole source of phosphorus, the responded to this situation primarily in the same way as phosphate-limited cultures: The activity of alkaline phosphatase increased drastically, which under natural conditions would enable the cells to compensate for the shortage of phosphate . Subsequent transfers, however, resulted in a quite different response: While the phosphatase activity of phosphate-limited cells stays at a high derepressed level, its increase was followed by a gradual decline in organisms grown on phosphite of hypophosphite . After eight to ten transfers on these P-compounds, phosphatase activity was back to its initial, repressed, low level, indicating that the cells were fully adapted to these substrates . Adaptation to either PO3-3 or PO3-2 was completely abolished if the cells were again grown with PO3-3 as P-source, whereafter the entire process of adaptation had to be repeated . The observed adaptation pattern, reflected by the alterations of phosphatase activity, was qualitatively equal with PO3-3 and PO3-2, but quantitatively different, because the response to hypophosphite gave much higher values than the increase obtained with phosphite . Phosphite-adapted cells are not simultaneously adapted to hypophosphite, but their response to the latter was less intense than observed after direct transfers from PO3-4 to PO3-2 . Adaptation to hypophosphite, however, led simultaneously to phosphite adaptation, so that these cells can utilize both P-compounds as a substitute for phosphate.

Biochim Biophys Acta, 1977 Feb 4, 464(3), 562 - 70
ATP-dependent proton translocation and quenching of 9-aminoacridine fluorescence in inside-out membrane vesicles of a cytochrome-deficient mutant of Escherichia coli,; Singh AP et al.; 1 . ATP-dependent proton translocation and ATP-dependent quenching of the fluorescence of 9-aminoacridine were measured in inside-out vesicles derived from a cytochrome-deficient mutant of Escherichia coli . 2 . ATP-dependent quenching of fluorescence was inhibited by nigericin gramicidin, NH4Cl, and carbonylcyanide-m-chlorophenylhydrazone . Inhibition was also produced by the ATPase inhibitors N,N'-dicyclohexylcarbodimide (DCCD) and diphenyl phosphorazidate (DPA), and by the respiratory chain inhibitors piericidin A, 2-heptyl-4-hydroxyquinoline N-oxide, and An2+ . The inhibition of ATP-dependent fluorescence quenching by the ionophores, uncouplers, and respiratory chain inhibitors was not due to an effect on ATPase activity which was insensitive to these agents . 3 . By use of the ATPase inhibitors DCCD and DPA, or by replacing ATP with GTP, ITP and CTP, a correlation between the ATPase activity and the rate of ATP-dependent membrane energization, as measured by fluorescence quenching, was obtained.

Biochim Biophys Acta, 1977 Feb 3, 474(3), 363 - 77
Triton X-100 activates nucleoside triphosphate-dependent, recBC-dependent DNA synthesis in toluene-treated Escherichia coli; Harper DJ et al.; Escherichia coli cells whose chromosome replication has been terminated in vivo, either by growth into stationary phase or by incubation of a mutant carrying a temperature-sensitive initiation mutation under restrictive conditions, are inactive in in vitro DNA synthesis as measured in toluene-treated cells . Addition of the non-ionic detergent Triton X-100 to such inactive systems results in a marked stimulation of ATP-dependent in vitro DNA synthesis . This Triton-stimulated DNA synthesis appears to proceed by a semi-conservative mechanism, in that DNA synthesized in vitro in the presence of a density labeled precursor bands in CsCl equilibrium centrifugation at a hybrid density . Neutral sucrose gradient centrifugation demonstrates that most of this hybrid material exhibits a molecular weight in excess of 1 X 10(7) . Triton-stimulated synthesis requires the presence of DNA polymerase III, as does normal in vivo replication . We show here, however, several anomalous properties of the DNA synthesis in the Triton/toluene system . In particular, Triton-stimulated synthesis is absent in cells harboring a recB mutation which lack the ATP-dependent exonuclease V, an enzyme implicated in recombinational repair synthesis in vivo . Furthermore, the ATP requirement for Triton-stimulated synthesis is relatively non-sepcific, and a variety of nucleoside triphosphates can effectively substitute for ATP . Finally, despite their high molecular weight in neutral sucrose gradient centrifugation, Triton-stimulated DNA synthesis generates DNA molecules of low molecular weight (less than 500 000) as determined by alkaline sucrose gradient centrifugation . In contrast, DNA synthesis in the normal toluene-treated cell system is not dependent on recB activity, shows a nearly absolute requirement for ATP which cannot be replaced by other nucleoside triphosphates, and produces molecules of far greater molecular weight as measured on alkaline sucrose gradients . Taken altogether the data strongly suggest that Triton activates an unusual form of DNA synthesis in toluene-treated cells which shows both repair and replicative aspects . These results caution against the use of Triton-activated toluene-treated cells system, for studying simple replicative DNA synthesis.

J Virol, 1977 Feb, 21(2), 694 - 712
Replication process of the parvovirus H-1 . VI . Characterization of a replication terminus of H-1 replicative-form DNA; Rhode SL III; The linear duplex replicative form (RF) DNA of the parvovirus H-1 has been characterized with respect to cleavage by the bacterial restriction endonuclease of Escherichia coli, EcoRI . RF DNA has a single cleavage site 0.22 genome length from the left end of the molecule . The molecular weight of H-1 RF DNA determined by gel electrophoresis is 3.26 X 10(6) . H-1 RF DNA has been found to dimerize by hydrogen-bounded linkage at the molecular left end, and in some molecules the viral strand is covalently linked to the complementary strand . Some 10% of monomeric RF DNA also has a covalent linkage between the viral and complementary strands at the left end . The EcoRI-B fragment, containing the left end of the RF molecule, appears to be a replication terminus by its labeling characteristics for both RF and progeny DNA synthesis . These findings suggest that the left end of H-1 RF DNA has some type of "turn-around" structure and that this end is not an origin for DNA synthesis.

Eur J Biochem, 1977 Feb, 72(3), 465 - 78
Studies on the sequence of the 3'-terminal region of turnip-yellow-mosaic-virus RNA; Silberklang M et al.; A fragment representing the 3'-terminal 'tRNA-like' region of turnip yellow mosaic (TYM) virus RNA has been purified following incubation of intact TYM virus RNA with Escherichia coli 'RNase P' . This fragment, which is 112+3-nucleotides long has been completely digested with T1 RNase and pancreatic RNase and all the oligonucleotides present in such digests have been sequenced using 32P-end labelling techniques in vitro . The TYM virus RNA fragment is free of modified nucleosides and does not contain a G-U-U-C-R sequence . Using nuclease P1 from Penicillium citrinum, the sequence of 26 nucleotides from the 5' end and 16 nucleotides from the 3' end of this fragment has been deduced . The nucleotide sequence at the 5' end of the TYM virus RNA fragment indicates that this fragment includes the end of the TYM virus coat protein gene.

Genetics, 1977 Feb, 85(2), 203 - 8
Complementation test between alkaline phosphatase regulatory mutations phoB and phoRc in Escherichia coli; Pratt C et al.; A phoRc and a phoB mutation belong to the same complementation group suggesting that there is a single positive control gene for alkaline phosphatase synthesis.

Genetics, 1977 Feb, 85(2), 193 - 201
Regulation of newly evolved enzymes . III Evolution of the ebg repressor during selection for enhanced lactase activity; Hall BG et al.; The evolution of lactose utilization by lacZ deletion strains of E . coli occurs via mutations in the ebg genes . We show that one kind of mutation in the regulatory gene ebgR results in a repressor which retains the ability to repress synthesis of ebg enzymes, but which permits 4.5-fold more ebg enzyme synthesis during lactose induction than does the wild-type repressor . A comparison between the growth rate of various ebg+ strains on lactose and the amount of ebg enzyme synthesized by these strains shows that the rate of enzyme synthesis permitted by the wild-type repressor is insufficient for growth on lactose as a sole carbon source by a cell with the most active ebg lactase yet isolated . We conclude, therefore, that the evolution of lactose utilization requires both a structural and a regulatory mutation.

J Gen Microbiol, 1977 Feb, 98(2), 485 - 91
Monitoring enzyme synthesis as a means of studying peptide transport and utilization in Escherichia coli; Bell G et al.; A new method has been developed for measuring peptide transport in aminoacid auxotrophs of Escherichia coli by following induction of beta-galactosidase . Appearance of the enzyme was determined after addition of inducer and peptides to amino-acid starved bacteria . For a given number of lysine equivalents, the rate and the extent of enzyme synthesis were the same for lysine and lysyl peptides; similar results were found for glycine and glycl peptides . Saturation constants for peptide transport were determined from the exogenous peptide concentration that gave half maximal rates of enzyme synthesis . The saturation constants, studies with mutants defective in peptide transport, and detection of competition between peptides for uptake, all endorsed earlier conclusions from growth tests about the structural specificities for peptide transport . The new method is quicker, more sensitive and more informative than growth tests.

Appl Environ Microbiol, 1977 Feb, 33(2), 482 - 4
Correction for the inherent error in optical density readings; Lawrence JV et al.; Except at very low levels, uncorrected photometric determination of bacterial cell densities showed a decreasing proportionally to actual cell density or dry weight . A standard curve was prepared to convert photometric readings to truly proportional optical density values . With one dry weight determination, optical density values may be converted to absolute dry weight values.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 492 - 5
Isolation of a multi-enzyme complex of fatty acid oxidation from Escherichia coli; Binstock JF et al.; A multi-enzyme complex of fatty acid oxidation has been isolated from E . coli B cells and has been purified to near homogeneity by a simple two-step procedure . The complex exhibits thiolase (EC 2.3.1.9), enoyl-CoA hydratase (EC 4.2.1.17), and 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) activities towards short-, medium-, and long-chain substrates . The complex has been estimated to have a molecular weight of approximately 300,000 and is apparently composed of two types of subunits with molecular weights of 78,000 and 42,000.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 487 - 91
Functional expression of cloned yeast DNA in Escherichia coli; Ratzkin B et al.; A collection of hybrid circular DNAs was constructed in vitro using the poly(dA-dT) "connector" method: each hybrid circle contained one molecule of poly(dT)-tailed DNA of plasmid ColE1 (made linear by digestion with EcoRI endonuclease) annealed to a poly(dA)-tailed fragment of yeast (Saccharomyces cerevisiae) DNA, produced originally by shearing total yeast DNA to an average size of 8 X 10(6) daltons . This DNA preparation was used to transform E . coli cells, selecting colicin-E1-resistant clones that contain hybrid ColE1-yeast DNA plasmids . Sufficient numbers of transformant clones were obtained to ensure that the hybrid plasmid population was representative of the entire yeast genome . Various hybrid ColE1-yeast DNA plasmids capable of complementing E . coli auxotrophic mutations were selected from this population . Plasmid pYeleu 10 complements several different point or deletion mutations in the E . coli or S . typhimurium leuB gene (beta-isopropylmalate dehydrogenase); plasmids pYeleu11, pYeleu12, and pYeleu17 are specific suppressors of the leuB6 mutation in E . coli C600 . Plasmid pYehis2 complements a deletion in the E . coli hisB gene (imidazole glycerol phosphate dehydratase) . Complementation of bacterial mutations by yeast DNA segments does not appear to be a rare phenomenon.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 452 - 6
Lipid and protein segregation in Escherichia coli membrane: morphological and structural study of different cytoplasmic membrane fractions; Letellier L et al.; Lipid and protein segregations can be induced in E . coli cytoplasmic membranes by conformational transitions of their lipid hydrocarbon chains from a disordered to an ordered state . For E . coli strain K 1059 (an unsaturated fatty acid auxotroph) supplemented with linolenic acid, the segregation leads to large areas of membrane surfaces having distinctly different morphological characteristics (smooth compared with strongly particulated fracture faces, as visualized by freeze fracture electron microscopy) . The different regions are physically separated by osmotic lysis of spheroplasts at temperatures below those of the order-disorder transition of the lipid hydrocarbon chains . The analysis of the different cytoplasmic membrane fractions provides a direct demonstration and allows a direct analysis of the segregation . As compared to the nonfractionated membranes, the membrane regions corresponding to the smooth fracture surfaces are poor in proteins, rich in lipids, and enriched in saturated fatty acids, while the membrane regions corresponding to the strongly particulated fracture surfaces are rich in proteins, poor in lipids, and enriched in unsaturated fatty acids . Quantitative information about the extent of these segregations is obtained from high-angle x-ray diffraction of the different membrane fractions and of the corresponding total lipid extracts.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 442 - 6
Preparation and characterization of a modified form of beta2 subunit of Escherichia coli tryptophan synthetase suitable for investigating protein folding; Hogberg-Raibaud A et al.; Globular proteins often appear to consist of distinct compact "domains," and the assumption is frequently implicitly made that these domains correspond to intermediate structures in the folding process . If this assumption is correct, the polypeptide fragment that builds up a domain should be able to spontaneously fold into its native conformation even when isolated . In an attempt to isolate and study such a fragment, the beta2 subunit of tryptophan synthetase {tryptophan synthase, L-serine hydro-lyase (adding indoleglycerol-phosphate), EC 4.2.1.20} has been subjected to controlled proteolysis . The resulting protein is shown to be a dimer, the protomer of which contains two nonoverlapping polypeptide chains of molecular weights 12,000 and 29,000 . Though inactive, the nicked protein is shown to be in a conformation that closely resembles that of the original enzyme, since it still can form an enzyme-bound intermediate of the catalytic reactions . The fluorescence of this intermediate is used to characterize the binding sites for the cofactor (pyridoxal-P) and substrates, which are shown to exist on the nicked protein . The possibility is discussed of using the fragments isolated from the nicked protein to study individual steps of the enzymatic reaction, intracistronic complementation, and the folding process in the normal beta2 subunit.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 437 - 41
Isomeric aminoacyl-tRNAs are both bound by elongation factor Tu; Hecht SM et al.; Recent suggestions that elongation factor Tu (EF-Tu) is specific for 2'-O-aminoacyl-tRNA, as compared with the 3'-isomer, prompted us to assay {3H}aminoacyl-tRNAs from Escherichia coli terminating in 2'- or 3'-deoxyadenosine for binding to EF-Tu to determine the possible positional specificity of the factor . Binding of modified aminaocyl-tRNAs to EF-Tu-GTP was measured both as a function of the ability of EF-Tu-GTP to diminish the rate of chemical deacylation of {3H}aminoacyl-tRNAs and by gel filtration of the individual ternary complexes . Fifteen different tRNA isoacceptors were tested by the deacylation procedure, including three (tRNAAsp, tRNACys, and tRNATyr) for which isomeric modified aminoacyl-tRNAs were available . All of the modified aminoacyl-tRNAs were protected fromdeacylation, although generally to a lesser extent than the corresponding unmodified species . Six modified tRNA isoacceptors (including tRNATrp and tRNATyr, for which both modified aminoacyl-tRNAs were accessible by enzymatic aminoacylation) were used in gel filtration experiments to permit direct measurement of the individual aminoacyl-tRNA-EF-Tu-GTP complexes . These experiments were also done in the presence of equimolar amounts of the corresponding unmodified {14C}aminoacyl-tRNAs, and the relative affinities for a limiting amount of EF-Tu-GTP were measured . The results were completely consistent with those obtained by the deacylation procedure and indicated that EF-Tu can bind to both positional isomers of aminoacyl-tRNA with no obvious preference for either.

J Biochem (Tokyo), 1977 Feb, 81(2), 381 - 8
Effects of polyamines on the activities of Escherichia coli ribonuclease I and II; Kumagai H et al.; The effects of polyamines on the breakdown of synthetic polynucleotides {poly(A), poly(C), and poly(U)} by E . coli ribonuclease I {ribonucleate 3'-oligonucleotidohydrolase, EC 3.1.4.23} and ribonuclease II {EC 3.1.4.1} have been studied . The degradation of poly(C) by RNase II was stimulated by spermine and spermidine, while that of poly(A) by RNase II was not affected by polyamines . Under our standard experimental conditions, the breakdown of poly(U) by RNase II was inhibited slightly by polyamines . The stimulatory effect of spermine and spermidine on the breakdown of poly(C) occurred in the absence of monovalent cations but not in the absence of divalent cations . When polyamines were used as a stimulant of RNase II, the ratio of poly(C) degradation to poly(U) degradation was greater in the presence of inhibitors such as poly(G) than in their absence . Although the breakdown of all synthetic polynucleotides by RNase I was stimulated by polyamines, the degree of stimulation by polyamines was in the order poly(C)greater than poly(A)(see text)poly(U) . However, the difference in degree of stimulation among polynucleotides decreased as monovalent cation concentration was increased.

Infect Immun, 1977 Feb, 15(2), 676 - 8
Improved minca medium for the detection of K99 antigen in calf enterotoxigenic strains of Escherichia coli; Guinee PA et al.; The K99 antigen of Escherichia coli can be detected more readily in cultures grown on Minca medium at 37 degrees C for 6 to 8 h or grown on Minca plus 1% Iso VitaleX for 20 to 24 h.

Hoppe Seylers Z Physiol Chem, 1977 Feb, 358(2), 197 - 208
Immunochemical studies on phenylalanyl-tRNA synthetase from Escherichia coli; Hennecke H et al.; Antibodies against the alpha and beta subunits of phenylalanyl-tRNA synthetase were fractionated by ion exchange chromatography into different classes and then digested with papain to yield the respective Fab fragments . The preparations obtained were used to investigate (i) whether the alpha and beta polypeptides share any common antigenic determinants and (ii) whether immunological methods are able to resolve the catalytic function of the subunits of this enzyme (or principally of oligomeric enzymes) . As to the first problem, immunodiffusion and complement fixation experiments showed that there is no immunological relatedness between the subunits which argues against the existence of sequence homoligies . As to the second question investigated, it was found that any binding of immunoglobulins of Fab fragments to the alpha or the the beta subunit affects enzyme activity either in the direction of activation or inhibition . These results therefore show that the immunological approach is not appropriate for resolving subunit-specific funcitons, possibly as a consequence of conformational changes induced in the enzyme by the binding of the immunoglobulins of Fab fragments.

Am J Physiol, 1977 Feb, 232(2), E180 - 5
Glucose and lactate kinetics after endotoxin administration in dogs; Wolfe RR et al.; We studied the effects of E . coli endotoxin on the glucose and lactate kinetics in dogs by means of the primed constant infusion of {6(-3)H} glucose and Na-L-(+)-{U-14C} lactate . The infusion of endotoxin induced a transient hyperglycemic level, followed by a steady fall in plasma glucose to hypoglycemic levels . The rate of appearance (Ra) and the rate of disappearance (Rd) of glucose were both significantly elevated (P less than .05) for 150 min after endotoxin, after which neither differed from the preinfusion value . The metabolic clearance rate of glucose was significantly elevated at all times 30 min postendotoxin . By 30 min postendotoxin, Ra and Rd of lactate, plasma lactate concentration, and the percent of glucose turnover originating from lactate were significantly elevated and remained so for the duration of the experiment . We concluded that after endotoxin hypoglycemia developed because of an enhanced peripheral uptake of glucose and a failure of the liver to maintain an increased Ra of glucose . We also concluded that lactate became an important precursor for gluconeogenesis and an important metabolic substrate.

Nucleic Acids Res, 1977 Feb, 4(2), 491 - 9
Isolation of ribosomal protein-RNA complexes by nitrocellulose membrane filtration: equilibrium binding studies; Spicer E et al.; E . coli ribosomal proteins are retained by nitrocellulose filters . In contrast, 16S RNA passes through nitrocellulose filters . We have found that specific protein-RNA complexes involving single proteins also pass through nitrocellulose filters . Thus, by utilizing radioactively labeled r-proteins, nitrocellulose filtration can be used to study directly and sensitively the stoichiometry of r-protein-RNA association . The filtration process maintains near equilibrium conditions, making it applicable to weak as well as strong protein-RNA associations . We have used nitrocellulose filtration to obtain saturation binding curves for the association of proteins S4, S7, S8 and S20 with 16S RNA . In each case, the stoichiometry of binding was one mole of protein or less per mole of RNA . The stoichiometry of protein S8 binding to 16S RNA measured by filtration is comparable to that observed by sucrose gradient centrifugation . Association constants for the binding of proteins S4, S8 and S20 to 16S RNA have been determined by analysis of the saturation binding curves and were found to range from .3-6 X 10(7)M-1.

Nucleic Acids Res, 1977 Feb, 4(2), 445 - 55
On the mechanism of oligonucleotide-primed RNA synthesis . II . Synthesis of specific primer-initiated RNA copies suitable for DNA sequence analysis; Van Kreijl CF et al.; The effect of temperature and primer concentration on oligonucleotide-primed transcription has been studied using the separated strands of a well-defined natural DNA as template . Results were similar to those obtained in the homopolymer-directed model systems . At high temperature and excess primer concentration mainly primer-initiated RNA copies are synthesized . Omission of one ribonucleoside triphosphate also makes the termination specific . The unique RNA fragments thus obtained have been used to determine the perfectly-repeated sequence of 68 base pairs in this DNA.

Nucleic Acids Res, 1977 Feb, 4(2), 425 - 44
On the mechanism of oligonucleotide-primed RNA synthesis . I . Model studies with deoxyhomopolymer templates and Escherichia coli RNA polymerase; Van Kreijl CF et al.; We have studied the effect of temperature, primer chain length and primer concentration on the oligonucleotide-primed transcription by Escherichia coli RNA polymerase . Our experiments with the homopolymer model systems poly(dT) .oligo(A)n, poly(dA) .oligo(U)n and poly(dA) .oligo(dT)n lead to three main conclusions . First, de novo chain initiation on single-stranded templates is preferentially suppressed at higher temperatures . Second, stable annealing of template and primer is neither a prerequisite nor does it stimulate the primer-dependent transcription . Third, formation of the ternary enzyme-template-primer complex is a rate-limiting step in the oligonucleotide-primed RNA synthesis . The maximal rate of primer-stimulated RNA synthesis, moreover, is strongly dependent on the nature of the primer and decreases in the order oligo(A)-primed poly(A) synthesis greater than oligo(U)-primed poly(U) synthesis greater than oligo(dT)-primed poly(U) synthesis . We attribute this to differences in the rate at which the first nucleotide is added to the primer . Raising temperature and primer concentration renders transcription in the model systems almost completely primer-dependent . This can be useful in a transcription approach to DNA sequence analysis.

Mutat Res, 1977 Feb, 42(2), 191 - 204
Lethla effect of nitrous acid on Escherichia coli; Nagy Z et al.; The effect of nitrous acid (NA) on viability, integrity of cellular DNA and on membrane transport were studied in 5 strains of Escherichia coli . Stationary phase cells, grown on mineral salts medium, were exposed to NA . The viability of strains decreased in thefollowing order: W3110 wild-type greater than WP2 wild-type, WP2 uvrA greater than NG30 recA greater than P3478 polA . Alterations were found in the DNA sedimentation profile in alkaline sucrose gradient . Disturbance of DNA synthesis was measured by 3H-labelled thymidine ({3H}Thd) incorporation . No degradation of DNA was found after NA treatment . Low doses of NA caused significant inhibition of leucine and glucose transport into whole cells . The results are interpreted in terms of the multi-target action of NA causing the death of cells.

Leber Magen Darm, 1977 Feb, 7(1), 1 - 2
{Current concepts in the pathophysiology of the diarrhea (author's transl)}; Ewe K et al.; Diarrhea can be defined as increased frequency of bowel movements (greater than 3 per day) plus decreased consistency of stools (volume greater than 200 ml per defecation) . Two pathogenetic mechanisms have been intensively investigated and partially elucidated within the last years: 1 . Secretion of electrolytes and water by way of induction of an augmented synthesis of cAMP in the mucosa cell . Cholera enterotoxin and other bacterial toxins as well as VIP (vasoactive intestinal peptide) cause diarrhea by this mechanism . 2 . Certain substances such as dihydroxylated bile acids, diphenolic laxatives and probably fatty acids cause leakage of the tight junctions between mucosal cells and cause leakage of electrolytes and water back into the intestinal lumen.

J Infect Dis, 1977 Feb, 135(2), 313 - 7
Enterotoxigenic Escherichia coli isolated from food; Sack RB et al.; Approximately 8% of 240 isolates of Escherichia coli obtained from food of animal origin in the United States were found to be enterotoxigenic, as determined in adrenal cells, rabbit ileal loops, and assays in infant mice . These organisms were of diverse serotypes that are not included among the so-called enteropathogenic serotypes and would not have been identified by usual laboratory methods . These enterotoxigenic E . coli are of potential importance to public health.

J Dairy Sci, 1977 Feb, 60(2), 289 - 93
Immune responses of the bovine fetus; Conner GH et al.; The bovine fetus is capable of mounting an antibody response when a bacterial antigen (killed Escherichia coli) or viral antigen (live reovirus) is deposited into the amniotic fluid . Time required for the fetus to respond to bacterial antigen given orally (amniotic fluid) is approximately 10 to 14 days and 8 to 10 days for viral antigen . Calves vaccinated prenatally with E . coli from 9 to 102 days before birth and deprived of colostrum survived oral challenge doses of viable E . coli which killed calves not vaccinated prenatally . One mechanism of protection was the local production of antibody in the gastrointestinal mucosa where immunofluorescent techniques showed immunoglobulins IgG, IgM, and anti-E . coli antibody in the duodenum, jejunum, and ileum as well as in the jejunal lymph node . Prenatal vaccination has been used in the field for prevention of colibacillosis . However, the occurrence of some stillbirths and premature births indicates the need for further research before there can be widespread field application of the technique.

J Bacteriol, 1977 Feb, 129(2), 916 - 25
Spermidine-Deoxyribonucleic acid interaction in vitro and in Escherichia coli; Rubin RL; The binding of spermidine to deoxyribonucleic acid (DNA) was studied by equilibrium dialysis in a wide range of salt concentrations . The association constants ranged from 6 x 10(5) M-1 in 1 mM sodium cacodylate, pH 7.5, to 3 x 10(2) M-1 in 0.3 M NaCl . MgCl2 reduced spermidine-DNA interaction even more than NaCl so that in moderate-ionic-strength solutions (0.3 M NaCl, 0.002 M MgCl2) there was little detectable binding . Low-ionic-strength media were used to isolate DNA from Escherichia coli by a method shown to minimize loss of spermidine from the DNA . Considerable spermidine was associated with E . coli DNA, but control experiments indicated that complex formation had taken place during or after lysis of the cells . Exogenous DNA or ribonucleic acid added to spheroplasts at the time of their lysis caused most of the cellular spermidine to be scavenged by the extra nucleic acid . The data suggest that spermidine is relatively free in the cell and thereby capable of strong (high-affinity) associations with nucleic acids only after the ionic strength of the cell environment is lowered.

J Bacteriol, 1977 Feb, 129(2), 908 - 15
Effects of galU mutation on flagellar formation in Escherichia coli; Komeda Y et al.; Two mutants of Escherichia coli strictly deficient in uridine-diphosphoglucose pyrophosphorylase activity (galU) were found to have very small numbers of flagellar filaments and hooks . In these mutants, both the rate of flagellin (flagellar protein) synthesis and the amount of messenger ribonucleic acid specific for flagellin were considerably lower than in the parental strains . Motile revertants from the galU mutants were isolated and were found to carry a suppressor mutation, which was mapped in the flaH cistron . These strains formed swarms under conditions of catabolite repression; their intracellular concentration of cyclic adenosine 5'-monophosphate was the same as that in the parental strains . These results suggest that the outer membrane affects flagellar formation through the flaH gene product.

J Bacteriol, 1977 Feb, 129(2), 714 - 7
Delayed ultraviolet light-induced cessation of respiration by inadequate aeration of Escherichia coli; Joshi JG et al.; Inadequately aerated Escherichia coli B/r cultures did not shut their respiration off 60 min after ultraviolet light (52 M/m2 at 254 nm) as they did when well supplied with oxygen . Since cessation of respiaration is associated with cell death, the result suggested that oxygen toxicity by superoxide radicals generated by cell metabolism might be responsible for cell death . The specific activity of superoxide dismutase, which scavenges O2- radicals, increased twofold after 90 min of adequate aeration, but the specific activity of catalase remained constant . Respiration and viability of irradiated cells were affected not at all by the presence of superoxide dismutase and only slightly by the presence of catalase . Metal ions such as Mn2+ and Fe2+ inducers of superoxide dismutase, had no effect on respiration and viability . When irradiated cells were incubated under N2 for 90 min, the respiration, growth, and viability time-course responses were the same as for the cells not exposed to anareobiosis . We conclude that superoxide anions generated at the time of irradiation play no part in cessation delays the ultraviolet light-induced synthesis of proteins responsible for the irreversible cessation of respiration.

J Bacteriol, 1977 Feb, 129(2), 702 - 6
Transient rates of synthesis of five amionacyl-transfer ribonucleic acid synthetases during a shift-up of Escherichia coli; Reeh S et al.; The steady-state levels of a number of aminoacyl-transfer ribonucleic acid synthetases are known to be positively correlated with growth rate in Escherichia coli . To describe the regulation of these enzymes during a nutritional shift-up, use was made of the recent identification of polypeptide chains of several synthetases in whole cell lysates resolved by the O'Farrell two-dimensional gel system . A culture growing in acetate minimal medium was shifted to glucose-rich medium and pulse labeled with {3H}leucine and {3H}isoleucine for 30- or 6-s intervals during the 20 min after the shift . After mixing with a uniformly {35S}sulfate-labeled reference culture, the samples were subjected to two-dimensional gel electrophoresis . The 3H/35S ratio in the resolved synthetase polypeptides provided an accurate estimation of their transient rates of synthesis . Five aminoacyl-transfer ribonucleic acid synthetases (those for argnine, glycine, isoleucine, phenylalanine, and valine) exhibited an increase in formation within 30 to 90 s after the shift-up . The magnitude of the increases corresponded to the final steady-state values and were reached within 2 to 3 min . The addition to rifampin revealed that the increase in the differential rate of valyl-transfer ribonucleic acid synthetase formation was the result of increased messenger ribonucleic acid transcription and not of a relaxation of some translation restriction.

J Bacteriol, 1977 Feb, 129(2), 698 - 701
Ultraviolet induction of prophage lambda during inhibition of deoxyribonucleic acid synthesis by hydroxyurea; Lydersen BK et al.; Hydroxyurea inhibited synthesis of certain deoxyribonucleic acid (DNA) precursors and causes the cessation of DNA synthesis . It did not cause induction of lambda . Superinfection of an irradiated lysogen with lambdaind- could prevent induction, but the percentage of cells protected decreased as the time between irradiation and superinfection increased . The presence of hydroxyurea did not increase the time during which cells could be rescued by superinfection . The accumulation of DNA precursors after ultraviolet or ionizing radiation was not necessary for the induction of lambda prophage to occur.

J Bacteriol, 1977 Feb, 129(2), 658 - 67
Escherichia coli membrane proteins with an affinity for deoxyribonucleic acid; Kohiyama M et al.; From the membrane fraction of Escherichia coli K-12 strain, four protein fractions (peaks I, IIa, IIb, and III) which have affinity for deoxyribonucleic acid (DNA) have been isolated . The molecular weights of these proteins are between 12,000 and 8,000 . Only the peak III fraction contains a protein that binds preferentially to single-stranded DNA, whereas the others contain proteins that bind also to double-stranded DNA . The binding activity of the peak IIb protein is inhibited in the presence of polyuridylic acid . Peak I and peak IIa protein fractions behave like hydrophobic proteins.

J Bacteriol, 1977 Feb, 129(2), 651 - 7
Accumulation of nucleotides by starved Escherichia coli cells as a probe for the involvement of ribonucleases in ribonucleic acid degradation; Cohen L et al.; The acid-soluble ribonucleic acid degradation products formed by Escherichia coli cells starved for a carbon source have been identified . They comprise oligonucleotides, nucleoside diphosphates, 5'- and 3'-nucleoside monophosphates, nucleosides, and free bases . The majority of these products are excreted phates, nucleosides, and free bases . The majority of these products are excreted into the medium, and only small and constant amounts are kept in the pool . During carbon starvation at elevated temperatures, mutants deficient in ribonuclease I do not form oligonucleotides and 3'-nucleoside monophosphates, and mutants that contain a modified form of polynucleotide phosphorylase do not accumulate nucleoside diphosphates . 5'-Nucleoside monophosphates do accumulate, however, in a mutant containing thermoabile ribonuclease II, under conditions where more than 95% of all enzyme activity had been destroyed . The data presented confirm the participation of ribonuclease I and polynucleotide phosphorylase in the final steps of ribonucleic acid degradation and indicate that an exonuclease forming 5'-nucleoside monophosphates is also involved.

J Bacteriol, 1977 Feb, 129(2), 606 - 15
Escherichia coli K-12 structural kdgT mutants exhibiting thermosensitive 2-keto-3-deoxy-D-gluconate uptake; Lagarde AE et al.; A specific method is described for selecting thermosensitive mutants of Escherichia coli K-12 able to grow on 2-keto-3-deoxy-D-gluconate (KDG) and D-glucuronate at 2, but not at 42 degrees C . The extensive analysis of one such mutant is consistent with the conclusion that the carrier molecule responsible for KDG and glucuronate uptake becomes thermolabile . (i) Growth on a variety of carbon sources is perfectly normal at 28 and 42 degrees C, whereas in the same temperature range it gradually diminishes on KDG and glucuronate . (ii) The apparent Km value for KDG is about twofold in the range 25 to 40 degrees C . In the same temperature range, the Vmax values for KDG influx are higher for the mutant compared with those of the wild-type strain, but the optimum temperature is 34 degrees C instead of 38 degrees C . On the contrary, the Vmax values for glucuronate influx are lower for the mutant than for the parental strain, and the optimum temperature for both strains is shifted beyond 40 degrees C . (iii) The activation energies for KDG and glucuronate uptake are about twofold higher in the mutant than in the wild-type strain . (iv) Kinetics of counterflow under deenergized conditions (overshoot) at different temperatures indicate that the defect is located in the translocation step rather than in the processes involved in energy coupling . (v) The first-order rate constants for thermal denaturation are, respectively, 2.5- and 5-fold higher at 40 and 30 degrees C in the mutant than in the wild-type strain, and the activation energy for thermal denaturation is lower . (vi) The carrier molecule in the mutant is also much more sensitive to denaturation by N-ethylmaleimide . (vii) Four independent thermosensitive mutations and one revertatn were located by transduction in or near the kdgT locus, defined previously as the site of nonconditional KDG transport-negative mutations . These results support the conclusion that kdgT represents the structural gene coding for the KDG transport system.

J Bacteriol, 1977 Feb, 129(2), 580 - 8
Influence of the stringent control system on the transcription of ribosomal ribonucleic acid and ribosomal protein genes in Escherichia coli; Dennis PP; The fraction of the total ribonucleic acid (RNA) synthesis rate that is messenger RNA (mRNA) for ribosomal protein (r-protein) and ribosomal RNA (rRNA) has been estimated in valS(Ts) rel+ stringent and valS(Ts) relA1 relaxed strains of Escherichia coli during a partial inhibition of valyl-transfer RNA aminoacylation . The partial inhibition was accomplished by shifting the strains from the permissive growth temperature of 29.5 degrees C to the semipermissive temperature of 35.5 degrees C . The RNA synthesized at the elevated temperature was pulse labeled with {3H}uracil . The fraction of the total incorpoarted 3H radioactivity in r-protein mRNA or in rRNA was estimated by specific hybridization to the transducing phages gammaspc1, which carries about 15 r-protein genes and lambdailv5, which carries an rRNA transcription unit . The results clearly demonstrate that the rel gene influences the fraction of the total RNA synthesis rate that is r protein mRNA and rRNA; in the rel+ strain they are significantly increased relative to control cultures . This indicates that the expression of the genes coding for the RNA and protein component of the ribosome are most likely regulated at the level of transcription . Furthermore, it appears that the distribution of functioning RNA polymerase between rRNA genes, r-protein genes, and other types of genes is influenced by the rel gene control system; presumably this influence is mediated through the unusual nucleotide guanosine tetraphosphate.

J Bacteriol, 1977 Feb, 129(2), 569 - 73
Control of cell division in Escherichia coli: effect of amino acid starvation; Ron E et al.; The effect of amino acid starvation on cell division was studied in cells of Escherichia coli B . In this bacterial strain, deprivation of a required amino acid resulted in synchronous cell division upon restoration of the amino acid . This synchronization was apparently due to a shift forward in the cell cycle during the starvation . As a consequence, the cells divided at a size that was smaller than normal.

J Bacteriol, 1977 Feb, 129(2), 1129 - 40
Further mapping of IS2 and IS3 in the lac-purE region of the Escherichia coli K-12 genome: structure of the F-prime ORF203; Deonier RC et al.; The sequence organization of the F-prime ORF203 was determined by heteroduplex analysis . This large, type II F-prime (Scaife, 1967) contains lac, proC, and purE genes derived from the W1485 subline of Escherichia coli K-12 . The IS3 and IS2 elements previously found in the lac-proC-purE region derived from the 58-161 subline (Hu et al., 1975) are also present in the same locations in the bacterial deoxyribonucleic acid (DNA) from the W1485 subline . Recombination between the IS2 region of F and an IS2 element located between lac and proC on the bacterial DNA apparently led to the formation of the perental Hfr, OR21 . IS2 is thus directly repeated, with one copy of each element appearing at each of the two junctions between F and the bacterial sequences on ORF203 . The F plasmid is found together with ORF203 in the plasmid DNA, and this probably forms from ORF203 by recombination between the directly repeated IS2 elements . ORF203 appears to have been excised from the Hfr chromosome by recombination between the IS3 sequence alpha3beta3 located counterclockwise of lac and the directly repeated IS3 sequence alpha4beta4 located clockwise of purE.

J Bacteriol, 1977 Feb, 129(2), 1072 - 7
EcoRI cleavage sites in the argECBH region of the Escherichia coli chromosome; Devine EA et al.; The EcoRI cleavage of deoxyribonucleic acids (DNAs) from lambdadarg phages, carrying argECBH, has been examined . The phages are derived from the heat-inducible, lysis-defective strain lambda y199, and their bacterial DNA, including argECBH, is derived from Escherichia coli K-12 . Such cleavage of the phage DNAs, in each case, produces the D, E, and F segments of lambda . Additionally, these DNAs yield segments, ordered from left to right, of length (in kilobases {kb}) determined by electron microscopy and 0.7% agarose slab gel electrophoresis as follows: lambdadarg13 (ppc argECBH bfe), 13.9, 2.8, 1.5, and 5.6; lambdadarg14 (ppc argECBH), 3.0, 2.0, 17.3, and 6.2; and lambdadarg23 (argECBH), 18.4 and 6.2 . For lambdadarg13 sup102 DNA, the segment analogous to the 13.9-kb segment measures 12.2 kb . The direction from left to right corresponds to the clockwise orientation of the E . coli genetic map . The EcoRI segments define five cleavage sites near the arg region of the E . coli chromosome . For each of the DNAs, the arg genes occur on the largest segment produced . The 17.3-kb segment, being entirely bacterial, represents the argECBH-bearing EcoRI segment of the E . coli chromosome . The location of the arg genes was demonstrated electron microscopically in heteroduplex experiments.

J Bacteriol, 1977 Feb, 129(2), 1034 - 44
Mutants of Escherichia coli "cryptic" for certain periplasmic enzymes: evidence for an alteration of the outer membrane; Beacham IR et al.; Mutants in which the expression of periplasmic enzymes by whole cells is reduced (termed "cryptic") are also found to show greatly reduced uptake of labeled adenosine 5'-monophosphate (5'-AMP), providing a rapid assay for crypticity . The crypticity of 3'- and 5'-nucleotidase has been examined as a function of substrate concentration . The Km for 3'- or 5'-AMP increases in the cryptic mutants when whole cells are used as the enzyme source . The Vmax is not altered . Electrophoretic analysis of protein prepared from cell envelopes showed that three cryptic mutants have a polypeptide absent from the outer membrane and a relatively high proportion of a polypeptide in the inner membrane . Analysis of the molar ratios of constituent sugars of the lipopolysaccharides showed no differences between three cryptic mutants and the parent strain . One cryptic mutant (3--41), however, has altered sensitivity to phage T4 . By selection for phage resistance, derivatives of the cryptic mutants that are deoxycholate sensitive have been obtained . These mutants are no longer cryptic . We suggest that cryptic mutants have an altered outer membrane, with decreased permeability to 3'- and 5'-AMP, as a result of an altered polypeptide.

J Bacteriol, 1977 Feb, 129(2), 1020 - 33
Establishment of exponential growth after a nutritional shift-up in Escherichia coli B/r: accumulation of deoxyribonucleic acid, ribonucleic acid, and protein; Brunschede H et al.; The accumulation of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein was followed in cultures of Escherichia coli B/r during exponential growth in different media and for 2 h after a nutritional shift-up from succinate minimal medium (growth rate {mu1} = 0.67 doublings per h) to glucose plus amino acids medium (mu2 = 3.14 doublings per h) . During postshift growth of the culture, the amounts of RNA (R), DNA (D), and protein (P) increased such that the ratios of the increments (delta R/delta P; delta D/delta P) were constants (k1, k2) . This implies that the rates of accumulation of nuclei1:k2:1 . These constants change from their preshift value to their final postshift value (i.e., k1 and k2) within a few minutes after the shift . k1 is a function of the activity of ribosomes, whereas k2 is related to the initiation of rounds of DNA replication . These parameters and the observed change in the doubling time of RNA (= mu2/mu1) were used to derive kinetic equations that describe the accumulation of DNA, RNA, protein, and cell mass during the 2- to 3-h transition period after a shift-up . The calculated kinetics agree closely with the observed kinetics.

Eur J Biochem, 1977 Feb, 72(3), 559 - 69
The functional and fluorescence properties of Escherichia coli RNA polymerase reacted with fluorescamine; Damjanovich S et al.; 1 . Fluorescamine (4-phenylspiro{furan-2,(3)1'-phthalan}-3,3'-dione) reacts rapidly with Escherichia coli RNA polymerase and produces a fluorescent derivative which is inactivated to an extent dependent upon reagent concentration . Excess fluorescamine is rapidly hydrolysed . Reaction is with xi-amino gruops of lysine residues in all subunits as revealed by gel electrophoresis and fluorescence scanning . 2 . The extent of inactivation and fluorescence yield are diminished in the presence of added template, a finding which provides evidence for the existence of reactive and essential amino groups which can be at least partially shielded by DNA in the binary complexes . The relative decrease of fluorescence is greatest in the betabeta' subunits . Holoenzyme and core enzyme show essentially the same behavior . 3 . The inactivation of activity by fluorescamine is primarily at the level of initiation . Template binding and chain propagation are less affected . 4 . The enzyme derivatized by fluorescamine shows an intense fluorescence with a peak at 490 nm and an excitation maximum at 390 nm . The fluorescence lifetime is in the range of 3-8 ns and the emission is highly polarized . In reactions carried out at high ionic strength the fluorescence yield is approximately double that at low ionic strength and insensitive to the presence of template . 5 . Energy transfer is observed between the derivatized enzyme as donor and ethidium bromide as acceptor in the presence of template to which both the enzyme and intercalating dye are bound . The transfer efficiency is a function of the relative concentrations and of the conditions of reaction with fluorescamine . An average transfer distance of approx . 4-5 nm has been calculated suggesting a close proximity between bound polymerase and helical regions of the template.

Eur J Biochem, 1977 Feb, 72(3), 515 - 23
Selective inhibition of tRNATyr transcription by guanosine 3'-diphosphate 5'-diphosphate; Debenham P et al.; Guanosine 3'-diphosphate 5'-diphosphate (ppGpp) selectively reduces the synthesis of su+III tRNA from omega 80 psu+III DNA relative to the synthesis of omega 80 RNA in a system in vitro containing DNA and Escherichia coli RNA polymerase holoenzyme as the sole macromolecular components . The response of su+III tRNA synthesis to increasing salt and to temperature in the presence of ppGpp suggests that the nucleotide may reduce the affinity of the enzyme for su+III promoters . The Ki for the selective inhibition of tRNA synthesis by ppGpp is 4 muM in contrast to the value of 150 muM for the inhibition of rRNA synthesis.

JACEP, 1977 Feb, 6(2), 62 - 5
Necrotizing fasciitis: a persistent surgical problem; Defore WW Jr et al.; Necrotizing fasciitis is a rare but specific clinical entity which, if not diagnosed early and treated aggressively, is rapidly fatal . The disease was first described during the Civil War and continues to be associated with a 50% mortality . The infectious process is diagnosed by the presence of a widespread fascial necrosis with extensive undermining of the adjacent tissues . The initial mechanism of injury as well as the location and etiologic agent of the suppurative fasciitis may vary . A review of 41 cases of necrotizing fasciitis occurring over a 22-year period disclosed an overall mortality of 39% . Most often, the mortality was related to the severity of the associated diseases and a failure to recognize the disease process promptly . The rate may be lowered by early recognition and prompt surgical intervention coupled with intensive supportive therapy.

J Virol, 1977 Feb, 21(2), 560 - 4
Reproductive fitness of P1, P2, and Mu lysogens of Escherichia coli; Edlin G et al.; P1, P2, and Mu lysogens of Escherichia coli reproduce more rapidly than nonlysogens during aerobic growth in glucose-limited chemostats . Thus, prophage-containing stains of E . coli are reproductively more fit than the corresponding nonlysogens . If mixed populations are grown by serial dilution under conditions in which growth is not limited, both the lysogen and nonlysogen manifest identical growth rates . The increased fitness of the lysogens in glucose-limited chemostats correlates with a higher metabolic activity of the lysogen as compared with the nonlysogen during glucose exhaustion . We propose that P1, P2, Mu, and lambda prophage all confer an evolutionarily significant reproductive growth advantage to E . coli lysogenic strains.

J Virol, 1977 Feb, 21(2), 554 - 9
Increased reproductive fitness of Escherichia coli lambda lysogens; Lin L et al.; Lambda lysogens of Escherichia coli reproduce more rapidly than nonlysogens during aerobic growth in glucose-limited chemostats . If the environment is changed to anaerobic growth, the situation is reversed, and the lysogen reproduces more slowly than the nonlysogen . Based on a tetrazolium dye assay, the increased fitness of the lambda lysogen during aerobic growth seems to result from a continued high metabolic rate as glucose becomes limiting, whereas the metabolic rate of the nonlysogen declines . The lambda rex gene is required for the growth advantage of lysogens since lack of rex function causes lambda lysogens to lose their reproductive advantage over nonlysogens.

J Med Chem, 1977 Feb, 20(2), 233 - 6
P-Aminobenzoic acid derivatives as inhibitors of the cell-free H2-pteroate synthesizing system of Escherichia coli; Thijssen HH; A heterogeneous series of compounds, derived from p-aminobenzoic acid (PABA), has been investigated for their PABA-antagonistic potency in a cell-free H2-pteroate synthesizing system of E . coli . A prerequisite of compounds, other than sulfones or sulfonamides, to compete with PABA for the enzyme H2-pteroate synthetase appeared to be the presence of a p-aminobenzoyl moiety . Substitution of the carboxyl group of PABA by an ester, an amide, or a ketone function, however, strongly reduces the ability to interact with the PABA binding site on the enzyme . This decrease in affinity probably has to be ascribed to the inability to create a sufficient negative charge in the carbonyl part of these p-aminobenzoyl derivatives . The relatively high affinities of L-PABG (16), PABP (22), and the alpha-phenyl derivative of 22, as compared with the other substituted p-aminobenzamides and p-aminobenzene-1-alkanones, are explained by assuming that these compounds, besides interfering with the PABA receptor site, also interact with an accessory area on the enzyme.

J Lab Clin Med, 1977 Feb, 89(2), 308 - 15
Biological activities of tritiated endotoxins: correlation of the Limulus lysate assay with rabbit pyrogen and complement-activation assays for endotoxin; Tomasulo PA et al.; Tritiated endotoxins were prepared by three different methods . The biological activities of the tritiated endotoxins were determined by the Limulus amebocyte lysate assay, a rabbit pyrogen assay, and a complement-activation assay and were compared to native, unlabeled endotoxin . All three tritiated endotoxin preparations manifested adequate biological activity in each of the three assay systems, and all three assays ranked the biological activity of the different endotoxin preparations in the same order . Endotoxin tritiated by the Wilzbach procedure retained most of its biological activity and also had the highest specific radioactivity . The good correlation between the Limulus lysate, rabbit pyrogen, and complement-activation assays suggests that the same active site of the endotoxin molecule is identified by the three different assays.

J Hyg (Lond), 1977 Feb, 78(1), 95 - 8
Escherichia coli serotypes in the faeces of healthy adults over a period of several months; Shooter RA et al.; The faeces of nine subjects eating mainly at home were collected at regular intervals over periods ranging from 2--5 months . Although a large number of serotypes of E . coli were isolated, the variety per subject was lower than is usually found . In most subjects only a limited number of serotypes persisted over most of the periods of study while many serotypes were only isolated on single occasions.

J Cell Biol, 1977 Feb, 72(2), 292 - 301
Ultrastructure of a periodic protein layer in the outer membrane of Escherichia coli; Steven AC et al.; Matrix protein (36,500 daltons), one of the major polypeptides of the Escherichia coli cell envelope, is arranged in a periodic monolayer which covers the outer surface of the peptidoglycan . Although its association with the peptidoglycan layer is probably tight, the periodic structure of the peptidoglycan . Although its association with the peptidoglycan later is probably tight, the periodic structure is maintained in the absence of peptidoglycan, and is therefore based on strong protein-protein interactions . A detailed analysis of the ultrastructure of the matrix protein array by electron microscopy and image processing of specimens prepared by negative staining or by freeze-drying and shadowing shows that the molecules are arranged according to three fold symmetry on a hexagonal lattice whose repeat is 7.7 nm . The most pronounced feature of the unit cell, which probably contains three molecules of matrix protein, is a triplet of indentations, each approx . 2 nm in diameter, with a center-to-center spacing of 3nm . They are readily penetrated by stain and may represent channels which span the protein monolayer.

J Am Vet Med Assoc, 1977 Feb 1, 170(3), 340 - 2
Effect of oral inoculation of Escherichia coli on colostral antibody production in cattle; Ward AC et al.; Oral inoculation of approximately 1.2 x 10(9) viable Escherichia coli to pregnant cows resulted in increased blood serum and colostral whey titers to the "O" antigen . The antibody titers were more pronounced in colostral whey and were correlated with the inoculum strain of Escherichia coli . There was no correlation between antibody titers of the colostrum ingested and the resulting serum antibody titers of the calves . The incidence of diarrhea in calves did not correlate with the antibody titer in the colostrum . The occurrence of diarrhea was significantly greater in calves that did not ingest colostrum until they were 12 hours old, compared with calves that had free access to their dams and suckled within an hour of birth.

Fertil Steril, 1977 Feb, 28(2), 182 - 5
Isolation of a spermatozoal immobilization factor from Escherichia coli filtrates; Paulson JD et al.; A low-molecular weight spermatozoal immobilization factor (SIF) has been isolated from Escherichia coli cultures . This factor is stable to heating, freezing, and lyophilization, and immobilizes but does not kill spermatozoa . The concentration of spermatozoa influenced the effectiveness of the SIF in immobilizing spermatozoa, indicating that bacterial infections could have a greater influence on the oligospermic ejaculate than on a normal specimen . SIF is a stable factor and binds to spermatozoa via a reversible mechanism.

Acta Pathol Microbiol Scand {C}, 1977 Feb, 85(1), 65 - 72
In vitro stimulation of human lymphocytes by Bordetella Pertussis; Andersen V et al.; Bordetella pertussis (B.p.) induces blast transformation of human lymphocytes; whole killed B.p . are more efficient than extracts obtained by sonication . Similar responses were obtained with each of the four strains used in the Danish pertussis vaccine . B.p . with low amounts of Protective Antigen and Histamine-Sensitizing Factor also induced lymphocyte transformation, but were less toxic to the lymphocytes at high concentrations . The supernatants of B.p . cultures were purified with respect to Lymphocytosis Promoting Factor; evidence is presented that these purified fractions possess T-lymphocyte mitogenic activity . Lymphocytes from all normal humans were stimulated by B.p., including cells from cord blood . Cells from childbearing women, obtained immediately after delivery, showed a general depression of lymphocyte transformation including the response to B.p . Children with whooping cough had a lower lymphocyte response to B.p . than healthy children . A highly significant correlation was observed between the responses to B.p . and to E . coli in the adults and newborn examined . It is concluded that the major part of the lymphocyte transformation induced by B.p . is non-specific.

J Infect Dis, 1977 Feb, 135(2), 195 - 200
Variation in enterotoxigenicity of Escherichia coli; Echeverria P et al.; The possibility that the variable severity of diarrheal disease due to enterotoxigenic Escherichia coli might be explained by quantitative differences in the activity of heat-labile enterotoxin was examined . The amount of toxin secreted by 13 enteropathogenic strains of E . coli was quantitated by measurements of the toxin-dependent increase in adenosine 3':5'-cyclic phosphate (cyclic AMP) in Chinese hamster ovary cells . The activity ranged from 150 pmol of cyclic AMP/ml per mg of protein to 4,040 pmol/ml per mg . With three representative strains there was good correlation (r = -0.999; P less than 0.05) between the amounts of cyclic AMP accumulated intracellularly (4,040, 2,071, and 470 pmol of cyclic AMP/ml per mg of protein) and the ability of the filtrate to distend the rabbit ileal loop, as measured by the amounts of toxin required to produce half-maximal distension (50% effective dose, which had values of 11.5, 27.5, and 38.5 mg, respectively) . The observed strain-to-strain variation in toxin activity may explain the variation in severity of diarrheal disease caused by enterotoxigenic E . coli.

J Bacteriol, 1977 Feb, 129(2), 959 - 66
Functional mosaicism of membrane proteins in vesicles of Escherichia coli; Adler LW et al.; Membrane vesicles of Escherichia coli prepared by osmotic lysis of lysozyme ethylenediaminetetracetate (EDTA) spheroplasts have approximately 60% of the total membrane-bound reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase (ED 1.6.99.3) and Mg2+-adenosine triphosphatase (ATPase) (EC 3.6.1.3) activities exposed on the outer surface of the inner membrane . Absorption of these vesicles with antiserum prepared against the purified soluble Mg2+-ATPase resulted in agglutination of approximately 95% of the inner membrane vesicles, as determined by dehydrogenase activity, and about 50% of the total membrane protein . The unagglutinated vesicles lacked all dehydrogenase activity and may consist of outer membrane . Lysozyme-EDTA vesicles actively transported calcium ion, using either NADH or adenosine 5'-triphosphate (ATP) as energy source . However, neither D-lactate nor reduced phenazine methosulfate energized calcium uptake, suggesting that the observed calcium uptake was not due to a small population of everted vesicles . Transport of calcium driven by either NADH or ATP was inhibited by simultaneous addition of D-lactate or reduced phenazine methosulfate . Proline transport driven by D-lactate oxidation was inhibited by either NADH oxidation or ATP hydrolysis . These results suggest that the portion of the total population of vesicles capable of active transport, i.e., the inner membrane vesicles, are functionally a homogeneous population but cannot be categorized as either right-side-out or everted, since activities normally associated with only one side of the inner membrane can be found on both sides of the membrane of these vesicles . Moreover, the data indicate that oxidation of NADH or hydrolysis of ATP by externally localized NADH dehydrogenase or Mg2+-ATPase establishes a protonmotive force of the opposite polarity from that established through D-lactate oxidation.

J Bacteriol, 1977 Feb, 129(2), 948 - 58
Constitutive mutations in the controlling site region of the araBAD operon of Escherichia coli B/r that decrease sensitivity to catabolite repression; Colome J et al.; Strains of Escherichia coli B/r containing a deletion of the regulatory gene araC are Ara- . Slow-growing revertants of these strains were isolated and designated aralc because they contain a second mutation in a controlling site, aral, that allows for a low level of constitutive expression of the araBAD operon (Englesbert et al., 1969) . We mutagenized aralc delta C strains and selected mutants that grow faster in mineral L-arabinose medium . The new mutations, called araXc, map very close to the original aralc mutations and are in the controlling site region between araB and araC . The aralcXc delta C strains have a higher constitutive level of expression of the araBAD operon than the aralc delta C parents . The araXc mutations are cis acting and decrease the araBAD operon's sensitivity to catabolite repression . The araBAD operon is expressed equally well in ara delta C and ara C cya crp backgrounds . The repressor form of ara C protein is able to repress the constitutive synthesis due to the ara Xc allele.

Eur J Biochem, 1977 Feb, 72(3), 571 - 81
Purification and properties of a periplasmic protein related to sn-glycerol-3-phosphate transport in Escherichia coli; Boos W et al.; Protein GLPT, a periplasmic protein previously recognized as closely related to the active transport of sn-glycerol-3-phosphate in Escherichia coli was isolated by the cold osmotic shock procedure . It was purified by Sephadex chromatography and isoelectric focussing . The purified protein does not exhibit any detectable binding activity toward sn-glycerol-3-phosphate . It has no activity as a glycerol phosphatase nor as a glycerol kinase . Polyacrylamide gel electrophoresis in the presence of dodecylsulfate of the protein subsequent to treatment in urea, boiling in dodecylsulfate and crosslinking indicates that it occurs as an oligomeric protein composed of four identical subunits of 40 000 molecular weight . Membrane vesicles of wild-type strains that contain protein GLPT in whole cells loose it during vesicle preparation . However, they still exhibit high transport activity toward sn-glycerol-3-phosphate . Membrane vesicles prepared from glp T mutants that may or may not contain protein GLPT do not transport sn-glycerol-3-phospahte . We conclude from these results that protein GLPT does not participate in the energy-dependent active transport through the cytoplasmic membrane but could be involved in facilitating the diffusion of sn-glycerol-3-phosphate through the outer layers of E . coli.

Acta Pathol Microbiol Scand {B}, 1977 Feb, 85B(1), 103 - 7
K antigen determination of Escherichia coli by counter-current immunoelectrophoresis (CIE); Semjen G et al.; The application of the counter-current immunoelectrophoresis (CIE) for determination of E . coli acidic polysaccharide K antigen is described . The most appropriate dilutions of antigens and antisera were established after examination of six different K antigens with homologous OK antisera . According to this result all test strains for acidic polysaccharide K antigens, i.e . K1 to K57, K62, K74, K82, K53, K84, K92, K93, K94, K95, K96, K97, K98 and K100, were examined and OK antisera suitable for the CIE test were selected . The following reciprocal cross-reactions were found: K2 and K62; K7 and K56; K12 and K82; K13, K20 and K23; K18 and K22; K16 and K97, and K53 and K93 . The CIE method is now used as a routine test in our laboratory.

J Med Microbiol, 1977 Feb, 10(1), 77 - 85
Evaluation of methods for the determination of Q and K antigens of an 02:K1(L) strain of Escherichia coli; Deb JR et al.; Tests made on ten colonies from a strain of Escherichia coli O2:K1 demonstrated that bacterial agglutination tests were reliable for identifying the O antigen of serogroup O2 but were unreliable for identifying the K1 antigen . The granular nature of K agglutination was not a reliable characteristic of the L type of K antigen . In contrast, indirect haemagglutination, immunodiffusion and immunoelectrophoresis tests with bacterial extracts gave consistent results with all colonies . The polysaccharide K1 antigen formed a long anodic precipitation line with two peaks, indicating its heterogenous nature, and partial fusion of this line with the O-antigen precipitation line suggested the presence of common serological determinants . In addition, a heat-labile protein antigen, possibly another K antigen, was identified by indirect haemagglutination tests and may have produced a short anodic precipitation line . The results also showed that the K1 antigen was still produced after storage of a culture for 12 years on Dorset-egg medium.

J Natl Cancer Inst, 1977 Feb, 58(2), 239 - 43
Effects of streptovaricins and their degradation products on RNA-directed DNA polymerase of Rauscher leukemia virus; Li LH et al.; The activities of streptovaricin complexes, streptovaricins, streptovals, and streptovarinic degradation products were elevated against RNA-directed DNA polymerases of Rauscher leukemia virus, DNA-dependent DNA polymerase of bacterial and mammalian cells, and DNA-dependent RNA polymerases of mammalian origin . The activities of streptovaricins were also listed for comparison purposes . The effects of streptovaricin complexes on viral DNA polymerases varied significantly from lot to lot, and streptovaricin complex lot 7 was the most active . All the streptovals and streptovaricin degradation products except varicinal A showed a marked improvement (twofold to tenfold) in activity against the viral enzyme over the parent streptovaricins . None of these compounds, however, displayed any significant effect on either the DNA polymerase of L1210 leukemia cells and Escherichia coli or the RNA polymerase of isolated nuclei of mouse liver . As a result of tests in these systems, some specific inhibitors of RNA-directed DNA polymerases of Rauscher leukemia virus were selected.

J Gen Microbiol, 1977 Feb, 98(2), 519 - 28
Evaluation of the role of methional, 2-keto-4-methylthiobutyric acid and peroxidase in ethylene formation by Escherichia coli; Primrose SB; During growth of Escherichia coli strain SPA O in the presence of methionine, an intermediate accumulates in the medium . This intermediate reacts with 2,4-dinitrophenylhydrazine, and can be degraded to ethylene either enzymically or photochemically, the latter being stimulated by the addition of a flavin . The pH optimum for the photochemical degradation of this intermediate and 2-keto-4-methylthiobutyric acid (KMBA) is pH 3 whereas the optimum for methional is pH 6 . The enzyme which converts the intermediate to ethylene also converts KMBA to ethylene and has many of the properties of a peroxidase including inhibition by catalase, cyanide, azide and anaerobiosis . The enzyme which synthesizes the intermediate is not known but requires oxygen and pyridoxal phosphate . A pathway for ethylene biosynthesis is proposed in which methionine is converted to KMBA which can be degraded either by peroxidase or in a flavin-mediated photochemical reaction . Its relevance to the properties of other ethylene-producing bacteria and to the proposed pathway of ethylene release by higher plants is discussed.

Proc Natl Acad Sci U S A, 1977 Feb, 74(2), 505 - 9
Membrane-associated assembly of M13 phage in extracts of virus-infected Escherichia coli; Wickner W et al.; Assembly of coliphage M13 is known to occur as the viral DNA crosses the cytoplasmic membrane, shedding its virus-coded DNA unwinding protein and acquiring from the membrane approximately 2400 copies of the major coat protein . Conditions are described in which extracts of M13-infected E . coli and membranes prepared from such extracts will support virus assembly at a rate equivalent to that of intact cells . Extracts prepared from cells infected with temperature-sensitive M13 mutants in genes 1, 3, 4, or 5 are temperature-sensitive in this cell-free assembly reaction . Phage assembly in vitro requires magnesium and as yet an unidentified heat-stable cofactor of low molecular weight . The rate of virus assembly is approximately linear with respect to extract concentration over a 10(4)-fold range, consistent with the observation that the entire M13 assembly activity copurifies with the cell membrane fraction.

J Biochem (Tokyo), 1977 Feb, 81(2), 371 - 9
Nucleoside triphosphate phosphohydrolase associated with cytoplasmic polyhedrosis virus; Shimotohno K et al.; Nucleoside triphosphate phosphohydrolase {EC 3.6.1.15} activity was found to be included in silkworm cytoplasmic polyhedrosis (CP) virus, which synthesizes mRNA carrying the 5'-terminal modification . This enzyme releases orthophosphate from the gamma-position in a nucleoside triphosphate, leaving nucleoside diphosphate . The rate of hydrolysis of ATP is faster than that of any other ribonucleoside triphosphate . Deoxy ATP is hydrolyzed rather faster than ATP . However, polynucleotides carrying triphosphate at the 5'-terminus, that is, 4S RNA which was synthesized by E . coli RNA polymerase {EC 2.7.7.6} using calf thymus DNA as a template, and the phage Q beta RNA (30S), are not effective substrates for this enzyme . Although the CP virion loses the viral genome and one kind of protein component on proteolytic treatment with pronase, the partially degraded virion still retains phosphohydrolase activity . The phosphohydrolase must therefore be associated firmly with the virion . This enzyme does not require the presence of nucleic acid for its function . Phosphohydrolysis of ATP by this enzyme activity represents a first step in the synthesis of the 5'-terminal modified mRNA of CP virus.

Infect Immun, 1977 Feb, 15(2), 396 - 401
Bacteriostatic effect of human milk and bovine colostrum on Escherichia coli: importance of bicarbonate; Griffiths E et al.; At pH 7.4 and in the presence of NaHCO3, human milk and bovine colostrum inhibited the growth of Escherichia coli O111 . Adding sufficient iron to saturate the iron-binding capacity of the lactoferrin present in the milk or colostrum prevented bacteriostasis . At pH 6.8 neither molk nor colostrum inhibited E . coli 0111 . Adjusting the pH to 7.4 with NaHCO3 resulted in the development of bacteriostatic activity . Adjusting the pH to 7.4 with NaOH was ineffective . Dialyzed colostrum and milk inhibited bacterial growth at pH 6.8 in the absence of added NaHCO3; addition of citrate or iron abolished bacteriostasis . The chromatographic elution profile of tyrosyl-transfer ribonucleic acid (tRNA) from iron-replete E . coli differs significantly from that of tyrosyl-tRNA from iron-deficient organisms . Examination of the elution profile tyrosyl-tRNA from E . coli 0111 growing in colostrum without added NaHCO3 showed that such bacteria were fully replete in iron . The nature of the elution profile of tyrosyl-tRNA also showed that iron was freely available to the bacteria when citrate was added to dialyzed colostrum but not available in its absence, even at pH 6.8 . Results support the idea that the bacteriostatic action of milk and colostrum, due to the combined action of antibody and lactoferrin, depends on the addition of bicarbonate to counteract the iron-mobilizing effect of the citrate normally present in these secretions.

J Bacteriol, 1977 Feb, 129(2), 967 - 72
Isolation of an Escherichia coli mutant deficient in thioredoxin reductase; Fuchs J; A mutant of Escherichia coli defective in thioredoxin reductase has been isolated and partially characterized . This mutant has no detectable thioredoxin reductase activity in vitro and yet it exhibits no in vivo defect in reduction of ribonucleotides . Evidence is presented that indicates that, in cells permeabilized via ether treatment, ribonucleoside diphosphate reduction can utilize glutathione as an alternate reducing system.

J Bacteriol, 1977 Feb, 129(2), 763 - 9
Adenosine 5'-triphosphate synthesis driven by a protonmotive force in membrane vesicles of Escherichia coli; Tsuchiya T; Adenosine 5'-triphosphate (ATP) synthesis energized by an artificially imposed protonmotive force (delta p) in adenosine 5'-diphosphate-loaded membrane vesicles of Escherichia coli was investigated . The protonmotive force is composed of an artificially imposed pH gradient (delta pH) or membrane potential (deltapsi), or both . A delta pH was established by a rapid alteration of the pH of the assay medium . A delta psi was created by the establishment of diffusion potential of K+ in the presence of valinomycin . The maximal amount of ATP synthesized was 0.4 to 0.5 nmol/mg of membrane protein when energized by a delta pH and 0.2 to 0.3 nmol/mg of membrane protein when a delta psi was imposed . Simultaneous imposition of both a delta pH and delta psi resulted in the formation of greater amounts of ATP (0.8 nmol/mg of membrane protein) than with either alone . The amount of ATP synthesized was roughly proportional to the magnitude of the artificially imposed delta p . Although p-chloromercuribenzoate, 2-heptyl-4-hydroxyquinoline-N-oxide, or NaCN each inhibits oxidation of D-lactate, and thus oxidative phosphorylation, none inhibited ATP synthesis driven by an artificially imposed delta p . Membrane vesicles prepared from uncA or uncB strains, which are defective in oxidative phosphorylation, likewise were unable to catalyze ATP synthesis when energy was supplied by an artificially imposed delta p.

Res Exp Med (Berl), 1977 Jan 28, 169(3), 213 - 9
{High-voltage electrophoresis of dihydrofolate reductase from Escherichia coli W 3110 (author's transl)}; Schalhorn A et al.; A method for the high-voltage electrophoresis of dihydrofolate reductase from Escherichia coli W 3110 is described . Dihydrofolate reductase catalyses the reduction of dihydrofolic acid to tetrahydrofolic acid . By addition of a tetrazolium salt, tetrahydrofolic acid reacts by formation of a violet water insoluble formazane which is an indicator for the enzyme . Besides several unspecific bands, two isoenzymes of the dihydrofolate reductase from Escherichia coli W 3110 are found which are specificially inhibited by the folate antagonists methotrexate and trimethoprime in a concentration of 0, 1muM, 1 muM respectively.

Science, 1977 Jan 28, 195(4276), 393 - 4
Plasmid detection and sizing in single colony lysates; Barnes WM; A simple and contained procedure for the rapid assay of the presence and size of plasmids similar to Col El is described . Bacteria are picked from an agar plate with a toothpick, lysed with dodecyl sulfate and heat, and placed directly on an agarose gel for electrophoresis.

Science, 1977 Jan 28, 195(4276), 391 - 3
Novel screening procedure for recombinant plasmids; Telford J et al.; Lysed bacterial colonies containing potential recombinant plasmids were mixed with molten agar and sealed into slots of an agarose gel . After electrophoresis overnight, the gel was stained with ethidium bromide, which clearly reveals recombinant plasmids . Xenopus laevis ribosomal DNA and histone DNA of Psammechinus miliaris were ligated into pCRI plasmids and screened by this method.

Science, 1977 Jan 28, 195(4276), 389 - 91
Nucleotide sequences from the rabbit beta globin gene inserted into Escherichia coli plasmids; Browne JK et al.; A 169-nucleotide region from the rabbit beta globin gene has been sequenced by analysis of complementary DNA's cloned in bacterial plasmids . Comparison of these sequences with those established for this gene by other techniques provides evidence of a high degree of fidelity and allows the unambiguous establishment that these plasmids do not contain harmful sequences.

J Biol Chem, 1977 Jan 25, 252(2), 483 - 91
Isolation and purification of double-stranded ribonuclease from calf thymus; Ohtsuki K et al.; A RNase from calf thymus, which specifically cleaves native or synthetic double-stranded RNA molecules endonucleolytically, has been isolated and purified from calf thymus . For optimal activity, the enzyme requires a sulfhydryl reagent and divalent cations; over 95 per cent of the activity is inhibited by 0.5 mm ethidium bromide . The degradation of {3H}poly(C)-poly(I) by purified enzyme preparations yields labeled dinucleotides and octanucleotides; the latter oligonucleotide contained 5'-phosphate and 3'-hydroxyl termini . The enzyme cleaves high molecular weight RNAs such as RNA products formed in vitro by T3 phage-induced RNA polymerase from T3 phage DNA, heterogeneous RNA isolated from duck reticulocyte nuclei, and 45 S RNA isolated from rat liver nucleoli . The mode of degradation of RNA in vitro with the double-stranded RNase is similar to that of Escherichia coli RNase III and appears to act endonucleolytically . The degradation of 45 S RNA with the enzyme results in the production of 29 S and 19 S RNA fragments . These findings suggest that the enzyme may be involved in the processing of high molecular weight precursor RNAs to mRNA or rRNAs in a manner analogous to that reported for RNase III of E . coli.

J Biol Chem, 1977 Jan 25, 252(2), 499 - 503
On the role of ATP in phosphodiester bond hydrolysis catalyzed by the recBC deoxyribonuclease of Escherichia coli; Eichler DC et al.; The deoxyribonuclease specified by the recB and recC genes of Escherichia coli (recBC DNase; exonuclease V) has been purified to near homogeneity by a new procedure . Although hydrolysis of even a single nucleotide from a duplex DNA molecule by the pure enzyme is absolutely dependent upon ATP, the extent of phosphodiester hydrolysis is strongly inhibited by ATP concentrations of 0.2 mm or greater, and the initial rate is unaffected . Under these conditions, the extent of DNA hydrolysis is proportional to enzyme concentration . In contrast, neither the rate nor the extent of hydrolysis of single-stranded DNA nor ATP is affected by high concentrations of ATP . The amount of large single-stranded polynucleotide generated by the action of the recBC DNase increases as the ATP concentration increases and, at 0.5 mM ATP, becomes equivalent to the amount of acid-soluble nucleotide formed . These findings suggest that high intracellular concentrations of ATP affect the mechanism of the recBC DNase so as to limit the extent of hydrolysis of duplex DNA, while at the same time favoring the formation of single-stranded regions within the duplex . Such regions may be essential intermediates in the recombination process.

J Biol Chem, 1977 Jan 25, 252(2), 471 - 8
Codon-acticodon recognition in the valine codon family; Mitra SK et al.; An in vitro protein-synthesizing system completely dependent on added valine tRNA (valyl-tRNAval) and programmed with RNA from the phage MS2 has been used to investigate the incorporation into MS2 coat protein of valine from isoaccepting valyl-tRNAsval with the anticodons U AC (U represents 5-oxyacetic acid uridine monophosphate), GAC, and IAC in response to the four valine codons GUU, GUC, GUA, and GUG . By examining the incorporation of valine into NH2-terminal and internal positions of three tryptic peptides from the MS2 coat protein it has been established that these anticodons each recognize all four valine codons . We therefore conclude that under our conditions of in vitro protein synthesis the genetic code, as far as the valine codons are concerned, is operationally a two letter code, i.e . the third codon nucleotide has no absolute discriminating function.

Biochemistry, 1977 Jan 25, 16(2), 298 - 305
Fluorescence and nucleotide binding properties of Escherichia coli uridine diphosphate galactose 4-epimerase: support for a model for nonstereospedific action; Wong SS et al.; The fluorescence emission spectrum for reduced diphosphopyridine nucleotide (DPNH) in Escherichia coli uridine diphosphate galactose 4-epimerase-DPNH complexes has a maximum at 435 nm, which is about twice as intense when the excitation is at 280 nm as at 340 nm . The fluorescence excitation spectrum monitored at 460 nm has two maxima, one at 340-345 nm and another about twice as intense at 280 nm . The polarization of DPNH fluorescence by these complexes is 0.43-0.44 compared with 0.46 for DPNH immobilized in propylene glycol at -20 degrees C . The small degree of fluorescence depolarization is due to rotational relaxation of the protein, relaxation time 205 ns . The excited-state lifetimes in epimerase-DPNH-nucleotide complexes are 3.5-4.2 ns . The fluorescence data show that the dihydropyridine ring in these complexes is highly immobilized and exhibits no detectable independent motion relative to rotational motions of the protein . The inhibition constants for uridine monophosphate (UMP) and 2,2,6,6-tetramethyl-4-piperidinyl-1-oxyl uridyl pyrophosphate acting as competitive reversible inhibitors of epimerase-DPN+ are 1.2 and 0.2 mM, respectively, at 27 degrees C in 0.1 M sodium bicinate buffer at pH 8.5 . A collection of Ki and Km values for uridine nucleotide inhibitors and substrates indicates that the principle substrate binding interactions involve the nucleotide moieties of substrates . Dissociation constants for uridine nucleotides dissociating from epimerase-DPNH-nucleotide complexes, measured by ultraviolet absorption and fluorescence techniques, are 12 muM for UMP, 14 muM for UDP-hexopyranoses, 4 muM for UDP-pentopyranoses, 27 muM for p-bromoacetamidophenyl uridyl pyrophosphate, 0.14 muM for UDP-4-ketohexopyranose intermediate, and 0.36 muM for UDP-4-ketopentopyranose intermediate at 27 degrees C in 0.1 M sodium bicinate buffer at pH 8.5 . Analysis of these data shows conclusively that the major part of the binding free energy for UDP-4-ketopyranose intermediates binding to epimerase-DPNH is attributable to the uridylpyrophosphoryl components and that the glycosyl-binding free energies are much smaller . The data show that the action of this enzyme does not require tight binding between the active site and glycosyl groups of either substrates or intermediates, although there is favorable binding of the uridylpyrophosphoryl components, particularly by epimerase-DPNH . It is postulated that nonstereospecific action results from and depends upon relatively weak, nonspecific active site binding of glycosyl groups in substrates and intermediates and that the uridylpyrophosphoryl groups serve as binding anchors in the epimerization process.

Biochemistry, 1977 Jan 25, 16(2), 241 - 9
Magnetic resonance and kinetic studies of the role of the divalent cation activator of RNA polymerase from Escherichia coli; Koren R et al.; The interaction of Mn2+, substrates and initiators with RNA polymerase have been studied by kinetic and magnetic resonance methods . As determined by electron paramagnetic resonance, Mn2+ binds to RNA polymerase at one tight binding site with a dissociation constant less than 10 muM and at 6 +/- 1 weak binding sites with dissociation constants 100-fold greater . The binding of Mn2+ to RNA polymerase at both types of sites causes an order of magnitude enhancement of the paramagnetic effect of Mn2+ on the longitudinal relaxation rate of water protons, indicating the presence of residual water ligands on the enzyme-bound Mn2+ . A kinetic analysis of the Mn2+-activated enzyme with poly(dT) as template indicates the substrate to be MnATP under steady-state conditions in the presence or absence of the initiator ApA . ATP and UTP interact with the tightly bound Mn2+ to form ternary complexes with approximately 50% greater enhancement factors . The dissociation constant of MnATP from the tight Mn2+ site as determined by longitudinal proton relaxation rate (PRR) titration (4.7 muM) is similar to the KM of MnATP in the ApA-initiated RNA polymerase reaction (10 +/- 3 muM) but not in the ATP-initiated reaction (160 +/- 30 muM) . Similarly, the dissociation constant of the substrate MnUTP from the tight Mn2+ site (90 muM) is in agreement with the KM of MnUTP (101 +/- 13 muM) when poly{d(A-T)}-poly{d(A-T)} is used as template, indicating the tight Mn2+ site to be the catalytic site for RNA chain elongation . Manganese adenylyl imidodiphosphate (MnAMP-PNP) has been found to be a substrate for RNA polymerase . It has the same affinity as MnATP for the tight site but, unlike the results obtained with MnATP, the enhancement is decreased by 43% in the enzyme Mn-AMP-PNP complex . These results suggest that the enzyme-bound Mn2+ interacts with the leaving pyrophosphate group . The initiators ApA and ApU and the inhibitor rifamycin interact with the enzyme-Mn2+ complex producing small (15-20%) decreases in the enhancement . The dissociation constant of ApA estimated from PRR data (less than or equal to 1.5 muM) agrees with that determined kinetically (1.0 +/- 0.5 muM) as the concentration of ApA required to produce half-maximal change in the KM of MnATP . In the presence of the initiation specific reagents ApA, ApU, or rifamycin, the affinity of the enzyme-Mn complex for ATP or UTP shows little change . However, ATP and UTP no longer increase the enhancement factor of the tightly bound Mn2+ but decrease it by 30-55%, indicating a change in the environment of the Mn2+-substrate complex on the enzyme when the initiation site is either occupied or blocked . Although the role of the six weak Mn2+ binding sites is not clear, the presence of a single tightly bound Mn2+ at the catalytic site for chain elongation which interacts with the substrate reinforces the number of active sites as one per molecule of holoenzyme and provides a paramagnetic reference point for further structural studies.

J Biol Chem, 1977 Jan 25, 252(2), 536 - 41
Nature of the free radical in ribonucleotide reductase from Escherichia coli; Sjoberg BM et al.; Ribonucleotide reductase from Escherichia coli consists of two nonidentical subunits, proteins B1 and B2 . The active site of the enzyme is made up from both subunits . Protein B2 contributes inter alia an organic free radical which gives a characteristic EPR signal . This radical was now located by isotope substitution experiments to the beta position of a tyrosine residue . The EPR spectrum of protein B2 from bacteria grown in a completely deuterated medium was drastically changed . The change was reversed by the addition of other protonated amino acids . The involvement in radical formation of the beta position of tyrosine was demonstrated from EPR spectra of protein B2 from bacteria grown in the presence of specifically deuterated tyrosine.

Biochemistry, 1977 Jan 25, 16(2), 306 - 11
Purification of membrane attachment and inhibitory subunits of the proton translocating adenosine triphosphatase from Escherichia coli; Smith JB et al.; The portion of Escherichia coli adenosine triphosphatase (ATPase) which is peripheral to the membrane (ECFl) is composed of five separate polypeptides referred to as alpha, beta, gamma, delta, and epsilon . Treating purified ECFl with pyridine precipitated the three larger polypeptides (alpha, beta, and gamma), but the two smaller ones (delta and epsilon), which represent only about 10% of ECFl, remained in solution . After removing the pyridine, both delta and epsilon were active and both were obtained in essentially pure form after chromatography on a single molecular-seive column . epsilon strongly inhibited the ATPase activity of ECFl, indicating that epsilon has a regulatory role in the enzyme . epsilon inhibited ECFl missing delta, indicating that delta is not required for inhibition by epsilon . However, enzyme containing just the alpha and beta subunits, which was prepared by treating ECFl with a protease, was fully active hydrolytically but not at all sensitive to inhibition by epsilon . This result suggests that the gamma polypeptide is required for the inhibition of the ATPase by epsilon . delta restored the capacity of ECFl missing delta to recombine with ECFl-depleted membrane vesicles . The ECFl, which became attached to the vesicles by the added delta, was functional in energy transduction, as evidenced by the coupling of ATP hydrolysis to the transhydrogenase reaction in the vesicles . The rebinding of ECFl missing delta was directly proportional to the amount of delta added until all the ECFl receptors in the membranes were occupied . delta may be a stalk which connects the Fl headpiece to the membrane, since the attachment of ECFl to the membrane exhibited an absolute dependence on delta . Although delta is known to have an apparent molecular weight of about 20,000 by gel electrophoresis in the presence of sodium dodecyl sulfate, the active delta eluted from a molecular-seive column with an apparent molecular weight of about 35,000, suggesting that in the active form delta is a dimer or rather elongated in shape . The active epsilon subunit eluted from the same column with an apparent molecular weight of about 16,000.

J Biol Chem, 1977 Jan 25, 252(2), 451 - 6
Purification and properties of the P15 specific restriction endonuclease from Escherichia coli; Reiser J et al.; The specific restriction endonuclease of the Escherichia coli plasmid, P15, has been purified to apparent homogeneity by a procedure that includes DNA-cellulose chromatography as well as a new endonuclease assay . Sedimentation on glycerol gradients showed two peaks of activity with values of 11.3 S and 15.7 S . The highly purified enzyme requires ATP and Mg2+ for activity and is stimulated by S-adenosylmethionine . A methylase activity is observed in the course of the endonucleolytic reaction which protects some of the DNA sites from cleavage.

Biochim Biophys Acta, 1977 Jan 21, 464(2), 328 - 37
The effects of N-ethylmaleimide on active amino acid transport in Escherichia coli; Janick PA et al.; N-Ethylmaleimide (MalNEt) binds covalently and without specificity to accessible sulfhydryl residues in proteins . In some cases specificity has been imposed on this reaction by manipulating reaction conditions, yielding information concerning both enzyme mechanism and the identity of specific proteins (for example C.F . Fox and E.P . Kennedy (1965) Proc . Natl . Acad . Sci . u.s . 54, 891-899) and R.E . McCarty and J . Fagan (1973) Biochemistry 12, 1503-1507) . We have examined the effects of MalNEt on the active accumulation of nine amino acids by Escherichia coli strains ML 308-225 and DL 54 . Whole cells have been used in order that transport systems both dependent on and independent of periplasmic binding proteins could be studied under various conditions of energy supply for transport . Our results suggest that the systems transporting ornithine, phenylalanine and proline are those most likely to undergo inactivation by direct reaction of MalNEt with the transport apparatus, rather than merely via side effects such as interruption of their energy supply . The inhibition of proline transport is specifically enhanced by the presence of proline, competitive inhibitors of proline transport, or carbonylcyanide p-trifluoromethyoxyphenylhydrazone during MalNEt treatment . The other eight systems tested showed no analogous effects.

Biochim Biophys Acta, 1977 Jan 20, 474(2), 210 - 7
Aminoacylation of rat liver transfer RNA with L-penicillamine . On the specificity of the aminoacylation reaction; Lodemann E et al.; L-}14C}Penicillamine is bound to RNA from rat liver in an in vitro reaction catalyzed by rat liver aminoacyl-tRNA synthetases . Addition of certain naturally occuring amino acids results in a significant decrease of L-penicillamine binding . The most potent inhibitor of this binding is L-valine, followed by L-isoleucine and L-threonine . Amino acids without structural relationship to L-penicillamine in the non-functional part of the molecule, such as L-phenylalanine, are ineffective . Studies on the competition of L-penicillamine and L-isoleucine, respectively, with L-valine demonstrate the high specificity of the aminoacylation reaction . They show that the change of L-penicillamine binding to tRNA Val is considerably lower than that of L-valine.

Biochim Biophys Acta, 1977 Jan 20, 474(2), 165 - 72
Synthesis of guanosine 5'-diphosphate, 3'-diphosphate in spot mutants of Escherichia coli; de Boer HA et al.; The synthesis of ppGpp in spoT- mutants of Escherichia coli has been invesitgated . In these mutants the first-order rate constant for ppGpp breakdown is low, and pppGpp is barely detectable . It is shown that the rate of pppGpp, and hence ppGpp, synthesis is strongly reduced compared with that observed in spot+ strains . The low rate of magic spot synthesis satisfactorily explains the low levels of pppGpp in spoT- mutants . The pentaphosphate very probably is the precursor of ppGpp as it is in wild-type, i.e . spoT+, strains.

Mol Gen Genet, 1977 Jan 18, 150(2), 183 - 91
Transcription of ribosomal protein genes carried on F' plasmids of Escherichia coli; Seals AA et al.; The transcriptional activity of the DNA sequences coding for certain ribosomal proteins has been measured in Escherichia coli . Two partial diploid strains were isolated from mating of a recA, argD, aroE recipient and an Hfr with an origin at 69.5 min . One contained an F' element carrying the genes from 69.5 to 72.7 min including the rpsL locus (72.4) and the second was diploid for the genes from 69.5 to 71.5 min but did not include any mapped ribosomal protein loci . The molecular weights of the plasmids were estimated to be 140 and 110 x 10(6) daltons, respectively . The extent of in vivo transcription of the chromosomal genes on the plasmid and the ribosomal protein mRNA fraction of the total cellular RNA weer calculated from DNA-RNA liquid hybridization experiments using both DNA and RNA excess procedures . The results indicated a high degree of transcriptional activity concentrated in the ribosomal protein sequences with 83% of the F' chromosomal sequences transcribed into mRNA products representing about 0.12% of the total cellular RNA.

Mol Gen Genet, 1977 Jan 18, 150(2), 161 - 70
Role of dnaB43 in F'-plasmid incompatibility; Jamieson AF et al.; In order to perform complementation tests with mutations of DNA replication of F'-plasmids incompatibility must overcome . We report out in ability to duplicate the results presented by Palchoudhury and Iyer (1971) and Bezanson and Iyer (1975) who have claimed to demonstrate the autonomous replication two incompatible F'-plasmids in a strain carrying the temperature sensitive dna B43 allele . In addition, we describe experiments designed to measured complementation using transient heterozygotes and compatible plasmids . Assessment of our data and those of others in the light of a recent report by Uhlin and Nordstrom (1975) suggests that new approaches will have to be developed for the successful employment of complementation analysis in F-plasmid genetics.

Biochem J, 1977 Jan 15, 162(1), 199 - 200
The phosphorylation of an acidic protein of the large ribosomal subunit of Krebs II ascites cells; Leader DP et al.; The ribosomes of Krebs II ascites cells contain an acidic protein, apparently analogous to proteins L7/12 of Escherichia coli . When ascites cells were incubated with {32P}Pi, this protein became labelled, indicating that it is a phosphoprotein.

Biochem J, 1977 Jan 15, 162(1), 183 - 7
Proton uptake linked to the 3-deoxy-2-oxo-d-gluconate-transport system of Escherichia coli; Lagarde AE et al.; Genetic and kinetic evidence is presented to show that the carrier-mediated uptake of the anionic sugars 3-deoxy-2-oxo-D-gluconate and D-glucuronate by Escherichia coli involves the concomitant transport of protons.

Differentiation, 1977 Jan 14, 7(2), 99 - 106
Ribosomal RNA synthesis in the Eastern North-American Newt, Notophthalmus viridescens; Reese DH; Ribosomal RNA (rRNA) synthesis, the initiation of which is an early major event during the transformation of iris into lens in the newt, was characterized in the TVI cell-line derived from the eastern North-American newt Notophthalmus viridescens . Employing the technique of polyacrylamide gel electrophoresis, molecular-weight measurements were made on newt rRNAs using Xenopus laevis and E . coli rRNAs as standards . The molecular weights of N . viridescens 28S and 18S rRNA were found to be 1.4 X 10(6) and 0.7 X 10(6) respectively . The precursor to these RNAs had a molecular weight of 3.1 X 10(6) . Three probable intermediates in the processing of precursor to mature rRNA were also identified . On the basis of the molecular weights of all species of RNA identified, a processing pathway, similar to that of Xenopus, has been suggested . Some unusual features in the kinetics of precursor rRNA labelling and processing suggest the possibility that newt-cell rRNA synthesis may be controlled by the availability of essential amino acids in a manner similar to that observed in mammalian cells . A possible relationship between the availability of essential amino acids, the initiation of rRNA synthesis in the newt iris, and the control of lens regeneration is discussed.

Biochim Biophys Acta, 1977 Jan 11, 480(1), 154 - 62
Spectral studies of the interactions of Escherichia coli alkaline phosphatase with 4-(4-aminophenylazo)-phenylarsonic acid; Szajn H et al.; Escherichia coli alkaline phosphatase (EC 3.1.3.1) is reversibly inhibited by a variety of phenylarsonic acids, including some N-haloacetylated derivatives . The inhibition is of the competitive type, and Ki values are reported . The action on the enzyme of one of the arsonate inhibitors, the azo dye, 4-(4-aminophenylazo)-phenylarsonic acid was studied in detail, using spectrophotometric and kinetic methods . The azo dye binds more strongly to E . coli alkaline phosphatase than do the other arsonates . Spectrophotometric titration indicates the presence of a single, strong dye-binding site on the enzyme dimer molecule in the concentration range covered . In 0.1 M Tris - HCl buffer pH 8.0, 25 degrees C K diss for the dye - enzyme complex is 1.50 - 10(-5) M as determined by spectrophotometric titration . This value is in good agreement with the Ki = 1.30 - 10(-5) M obtained from kinetic measurements . The dye can be displaced from alkaline phosphatase by phosphate and competitive inhibitor 2-aminoethyl phosphonate . These results indicate that the dye binds with its arsonic acid group to the anion binding site of the active site of the enzyme . The binding of the dye to the native enzyme is associated with a red shift in the visible spectrum of the dye . It seems that the aromatic portion of the dye interacts with a hydrophobic region close to the anion binding site . The spectrum of the dye is not changed in the presence of the apoenzyme . When zinc is added to an apoenzyme-dye solution, the spectral changes of the dye depend on both the ratio of zinc per apoenzyme and the pH . The presence of Mg2+ had no effect on the observed phenomenon.

Biochemistry, 1977 Jan 11, 16(1), 16 - 24
Transcription of yeast DNA by homologous RNA polymerases I and II: selective transcription of ribosomal genes by RNA polymerase I; Holland MJ et al.; Purified yeast DNA was transcribed by homologous RNA polymerases I and II and Escherichia coli RNA polymerase . Transcripts synthesized in vitro were analyzed by molecular hybridization with complementary DNA (cDNA) synthesized from yeast poly(A)-containing mRNA with viral reverse transcriptase and ribosomal DNA labeled in vitro by nick translation with E . coli DNA polymerase I . RNA synthesized by polymerase I and II in the presence of Mn2+ contained sequences complementary to cDNA and rDNA at a frequency consistent with random transcription of the template . Similarly, E . coli RNA polymerase synthesized an apparently random transcript in the presence of either Mn2+ or Mg2+ . In contrast to these results, RNA polymerase I but not polymerase II transcripts were markedly enriched in sequences complementary to rDNA when transcription was carried out in the presence of Mg2+ . The observed enrichment was 15-30-fold higher than observed for polymerase II or E . coli polymerase transcripts and is consistent with the transcript being comprised of 6-10% ribosomal sequences . These data strongly suggest that RNA polymerase I plays a critical role in selective transcription of ribosomal cistrons.

Biochim Biophys Acta, 1977 Jan 11, 480(1), 315 - 25
A cis-trans isomerising activity of Escherichia coli . Isomerization from 2-(2-furyl)-3-cis-(5-nitro-2-furyl) acrylamide (furylfuramide) to its trans isomer; Tomoeda M et al.; The soluble enzyme fraction derived from Escherichia coli K-12 JE2100 cells was found to exhibit, in addition to Nadh- and NADPH-dependent reductase activities, NADH-dependent cis-trans isomerising activity toward 2-(2-furyl-3-(5-nitro-2-furyl)acrylamide leading to a specific change in geometrical configuration of the vinyl group at the 2-position from cis to trans but not in the reverse direction . This furylfuramide-isomerising action of bacteria was dicoumarol insensitive, and did not require glutathione for full activity . The particulate enzyme fraction derived from JE2100 cells, although it showed little reductase activity toward furylfuramide in the presence of either NADH or NADPH, revealed an isomerising activity in the presence of NADH.

Biochim Biophys Acta, 1977 Jan 11, 480(1), 143 - 53
Metal ion-induced conformational changes in Escherichia coli alkaline phosphatase; Szajn H et al.; Ultraviolet difference spectra are produced by the binding of divalent metal ions to metal-free alkaline phosphatase (EC 3.1.3.1) . The interaction of the apoprotein with Zn2+, Mn2+, Co2+ and Cd2+, which induce the tight binding of one phosphate ion per dimer, give distinctly different ultraviolet spectra changes from Ni2+ and Hg2+ which do not induce phosphate binding . Spectrophotometric titrations at alkaline pH of various metallo-enzymes reveal a smaller number of ionizable tyrosines and a greater stability towards alkaline denaturation in the Zn2+- and Mn2+-enzymes than in the Ni2+-, Hg2+- and apoenzymes . The Zn2+- and Mn2+-enzymes have CD spectra in the region of the aromatic transitions that are different from the CD spectra of the Ni2+-, Hg2+- and apoenzymes . Modifications of arginines with 2,3-butanedione show that a smaller number of arginine residues are modified in the Zn2+-enzyme than in the Hg2+-enzyme . The presented data indicate that alkaline phosphatase from Escherichia coli must have a well-defined conformation in order to bind phosphate . Some metal ions (i.e . Zn2+, Co2+, Mn2+ and Cd2+), when interacting with the apoenzyme, alter the conformation of the protein molecule in such a way that it is able to interact with substrate molecules, while other metal ions (i.e . Ni2+ and Hg2+) are incapable of inducing the appropriate conformational change of the apoenzyme . These findings suggest an important structural function of the first two tightly bound metal ions in enzyme.

J Biol Chem, 1977 Jan 10, 252(1), 368 - 76
Nucleotide sequence of a fragment of SV40 DNA that contains the origin of DNA replication and specifies the 5' ends of "early" and "late" viral RNA . IV . Localization of the SV40 DNA complementary to the 5' ends of viral mRNA; Dhar R et al.; Cytoplasmic mRNA isolated from cells infected with SV40 was isolated by passage over oligo(dT)-cellulose columns . This RNA was annealed to SV40 DNA fragments produced by cleavage with EcoRII endonuclease . The RNA resistant to RNase digestion was analyzed by digestion with ribonucleases and oligonucleotide mapping . The results were compared with oligonucleotides from in vitro transcripts of the fragments and with whole genome SV40 cRNA which had been fractionated by hybridization to the fragments . The 5' ends of "early" and the large "late" SV40 mRNA, transcribed from opposite DNA strands, overlap for a region of 60 to 100 nucleotides . The region of overlap includes a portion of the segment of DNA containing the origin of DNA replication.

J Biol Chem, 1977 Jan 10, 252(1), 355 - 67
Nucleotide sequence of a fragment of SV40 DNA that contains the origin of DNA replication and specifies the 5' ends of "early" and "late" viral RNA . III . Construction of the total sequence of EcoRII-G fragment of SV40 DNA; Subramanian KN et al.; Limited T1 RNase digestion of subfragments of the SV40 DNA restriction endonuclease fragment EcoRII-G were prepared and analyzed . The fragments were separately labeled with 32P at their 5' terminus and the terminal sequences analyzed with limited snake venom diesterase digestion . The data permitted us to deduce the nucleotide sequence for EcoRII-G . The sequence contains a stretch of 17 A-T base pairs preceding the DNA complementary to the 5' end of "early" message RNA, a stretch of 27 bases with a perfect 2-fold rotational symmetry near the origin of DNA replication and a perfect tandem repeat of 21 nucleotides.

J Biol Chem, 1977 Jan 10, 252(1), 11 - 9
Purification and properties of Rauscher leukemia virus DNA polymerase and selective inhibition of mammalian viral reverse transcriptase by inorganic phosphate; Modak MJ et al.; Rauscher leukemia virus RNA-directed DNA polymerase has been purified to near homogeneity (greater than 90% pure) using affinity chromatography on polycytidylate-agarose with over 85% recovery of input enzymatic activity . The purified enzyme has a molecular weight of approximately 70,000 and appears to consist of a single polypeptide chain . The enzyme is free of DNase, but has RNase H activity . Analysis of the requirements for optimal rates of DNA synthesis by this enzyme using synthetic and natural template-primers has revealed template-specific variations in such requirements . During these studies it was observed that DNA synthesis catalyzed by Rauscher leukemia virus DNA polymerase is inhibited by the addition of inorganic phosphate . An analysis of the mechanism of phosphate inhibition was carried out using the synthetic template-primer poly(A)-(dT)10 . It appears that by some mechanism, possibly involving the substrate binding site of the enzyme, phosphate ions inhibit DNA synthesis with a more acute effect on the rate of chain growth than on that of initiation . The extension of these studies to DNA synthesis catalyzed by a variety of mammalian type C viral reverse transcriptases revealed that low levels ( less than or equal to 2 mM) of inorganic phosphate strongly inhibited DNA synthesis . The susceptibility to phosphate inhibition appears unique to mammalian type C viral enzymes since the type B viral enzyme, Escherichia coli DNA polymerase I, avian myeloblastosis virus and Mason Pfizer monkey tumor virus reverse transcriptase and cellular DNA polymerases alpha and gamma are not inhibited by inorganic phosphate . This phenomenon of phosphate inhibition of various DNA polymerases, therefore, provides a new basis for the differentiation of the sources and nature of these enzymes.

Mol Gen Genet, 1977 Jan 7, 150(1), 87 - 101
Interaction of alleles of the relA, relC and spoT genes in Escherichia coli: analysis of the interconversion of GTP, ppGpp and pppGpp; Fiil NP et al.; Mutants in the spo T gene have been isolated as stringent second site revertants of the relC mutation . These show varying degrees of the characteristics associated with the spoT1 gene, viz relative amount and absolute levels of both pppGpp and ppGpp and the decay rate of the latter . The entry of 3H-guanosine into GTP and ppGpr pools in spoT+ and spoT1 cells either growing exponentially or during amino acid starvation was determined, and the rate of ppGpp synthesis and its decay constant calculated . During exponential growth the ppGpp pool is 2-fold higher, its decay constant 10-fold lower, and its synthesis rate 5-fold lower in spoT- than in spoT+ cells; during amino acid starvation the ppGpp pool is 2-fold higher, its decay constant 20-fold lower, and its synthesis rate 10-fold lower in spoT than in spoT+ cells . In one of the "intermediate" spoT mutants the rate of entry of 3H-guanosine into GTP, ppGpp and pppGpp was measured during amino acid starvation . The data form the basis of a model for the interconversion of the guanosine nucleotides in which the flow is: GDP leads to GTP leads to pppGpp leads to ppGpp leads to Y . Calculations of the rates of synthesis and conversion of pppGpp and ppGpp under various conditions in various spoT+ and spoT- strains indicate that the ppGpp concentration indirectly controls the rate of pppGpp synthesis.

Mol Gen Genet, 1977 Jan 7, 150(1), 53 - 61
Lambdoid phages that simplify the recovery of in vitro recombinants; Murray NE et al.; Derivatives of phage lambda are described for use as vectors for fragments of DNA generated with the HindIII and EcoRI restriction enzymes . With some vectors, hybrid molecules are recognised by a change from a turbid to a clear plaque morphology resulting from the insertion of a fragment of DNA into the lambda gene coding for the phage regressor . Other vectors contain a central, replaceable fragment of DNA which imparts a readily recognisable phenotype . This central fragment may include either a gene for a mutant transfer RNA (suppressor) or a part of the lacZ gene of E . coli able to complement a lacZ host . The appropriate lacZ host and indicator plates permit the ready distinction between recombinant and vector phages by the colour of the plaques.

Mol Gen Genet, 1977 Jan 7, 150(1), 43 - 52
Joint molecules of lambda DNA as an intermediate of genetic recombination; Takahashi S; Joint molecules of lambda DNA formed in the absence of DNA replication, which may be involved in the process of genetic recombination can be observed as branched DNA derived from different phage particles . These molecules are associated through base-pair hydrogen bonding in synaptic regions, usually with short single-stranded gaps . Furthermore, joint molecules could be accumulated up to ten fold when lambda was irradiated with ultraviolet light before infection of polI mutant of E . coli . Infection at low multiplicity did not give rise to joint molecules . These results suggest that single-strand breaks and gaps introduced in duplex lambda DNA facilitate the formation of joint molecules.

Mol Gen Genet, 1977 Jan 7, 150(1), 29 - 36
Excision of a DNA sequence determining kanamycin resistance from a ColE1-Km recombinant plasmid; Bodsch W; A 4.8 X 10(6) dalton ECoRI-generated fragment of the R-factor R6-5 carrying the gene for kanamycin resistance (Km) was joined in vitro to ECoRI-treated ColE1 plasmid DNA . Transformation of E . coli with the ColE1-Km recombinant plasmid yielded clones, which were immune to colicin E1, resistant to kanamycin and failed to produce colicin E1 . During multiplication of this recombinant plasmid in the presence of chloramphenicol, cells expressed an increased resistance to kanamycin . Transformation studies with the recombinant DNA molecule showed very frequent loss of Km resistance in those cells harbouring a preexisting F'gal plasmid . Since colicin immunity is not affected and the col- phenotype is still present, one has to test for a remaining DNA sequence further existing in ColE1 DNA by cleaving the plasmid DNA with the ECoRI restriction endonuclease . The full length of ColE1 DNA (6.2 kb) was restored, which confirmed that no deletion of ColE1 DNA sequences had occured . The remaining DNA sequence was identified as a 2.0 or 2.2 kb segment . On the basis of the length of the excised fragment it is proposed that the insertion sequence ISI and a part of the inverted repeat sequence with corrdinates 21.0 to 22.0 of the R6-5 DNA are recognised by a nucleolytic function.

Mol Gen Genet, 1977 Jan 7, 150(1), 1 - 12
Excision-repair in mutants of Escherichia coli deficient in DNA polymerase I and/or its associated 5' leads to 3' exonuclease; Cooper P; The ultraviolet (UV) sensitivity of Escherichia coli mutants deficient in the 5' leads to 3' exonuclease activity of DNA polymerase I is intermediate between that of pol+ strains and mutants which are deficient in the polymerizing activity of pol I (polA1) . Like polA1 mutants, the 5'-exonclease deficient mutants exhibit increased UV-induced DNA degradation and increased repair synthesis compared to a pol+ strain, although the increase is not as great as in polA1 or in the conditionally lethal mutant BT4113ts deficient in both polymerase I activities . When dimer excision was measured at UV doses low enough to avoid interference from extensive DNA degradation, all three classes of polymerase I deficient mutants were found to remove dimers efficiently from their DNA . We conclude that enzymes alternative to polymerase I can operate in both the excision and resynthesis steps of excision repair and that substitution for either of the polymerase I functions results in longer patches of repair . A model is proposed detailing the possible events in the alternative pathways.

C R Acad Sci Hebd Seances Acad Sci D, 1977 Jan 3, 284(1), 105 - 8
{Immunological demonstration of large quantities of glycogen or of a glycogen-like substance in human embryonic colon cells and in colon carcinomas by means of rabbit antisera raised against a strain of Escherichia coli 013}; Zweibaum A et al.; Rabbit antisera raised against a strain of E . coli 013, with a strong antiglycogen activity, were tested on human fetal and normal adult colons, on colon carcinomas, and on colon tumor cells in culture (HT29) . Only very rare granules were present in adult normal colons when tested with the immunofluorescence method . In faetal colons, in 12 out of 14 carcinomas, and on HT29 cells, the immunofluorescent reactions were similar to those observed in normal liver . The reactions were negative after previous treatment with alpha-amylase . They were inhibited with glycogen, with phenol-alcohol, perchloric, and trichloroacetic extracts from faetal colons, and with a tumor trichloroacetic extract . The extracts precipitated with anti-E . coli 013 antisera . They had a strong inhibiting activity in a radioimmunoassay test with labeled glycogen . The extracts from normal adult colons did not precipitate with the antisera and they had no inhibiting activity in either immunofluorescence and radioimmunoassay tests.

Eur J Biochem, 1977 Jan 3, 72(1), 49 - 56
The effect of initiation factor IF-1 on the dissociation of 70-S ribosomes of Escherichia coli; Naaktgeboren N et al.; By means of exchange studies, in which 3H-labelled 50-S subunits and unlabelled 70-S ribosomes from Escherichia coli MRE 600 were used, it has been demonstrated that the 30-S subunit is the only target for IF-3 in the dissociation of 70-S ribosomes . The interference of IF-3 with the dynamic equilibrium of 70-S in equilibrium 50-S + 30-S occurs by binding of the factor to the 30-S subunit . The 30-S-IF-3 complex in impaired in the association reaction, which implies that IF-3 is acting as an anti-association factor . The action of IF-1 is two-fold . Firstly IF-1 increases the rate of exhcange of the ribosomal subparticles in the 70-S ribosome without changing the position of the equilibrium . Thus the spontaneous equilibrium is attained more rapidly in the presence of IF-1 . This kinetic effect of IF-1 is also demonstrated in the IF-3-mediated dissociation of 70-S ribosomes . Secondly IF-1 is able to increase the IF-3-mediated dissociation . It seems likely that the explanation for the latter phenomenon must be sought in the binding of IF-1 to 70-S ribosomes, resulting in a loosening of the ribosomes structure, as well as to 30-S . IF-3 complex, thaereby slowing down the association reactions of the subunits.

Eur J Biochem, 1977 Jan 3, 72(1), 191 - 200
The stereochemical basis of template function; Rackwitz HR et al.; The behavior of nucelotides with thioketo-substituted pyrimidine bases (4-thiouracil, 2-thiouracil and 2-thiocytosine) or amino-analogue purine bases (2-aminopurine and 2,6-diaminopurine) in transcription and translation was investigated . The experimental results obtained led to the following conclusions . 1 . The stereochemical basis of substrate selection in transcription is the geometry of Watson-Crick base pairs A-U (or A-T) and G-C between substrate and template bases . 2 . The topology of the active site of Escherichia coli RNA polymerase is precisely adopted to the geometry of Watson-Crick base pairs . 3 . The enzyme active site discriminates between A-U (A-T) and G-C base pairs . An essential feature in this discrimination is the 6-NH2 group of the A-U (A-T) base pair and the 2-keto group of cytosine in the G-C base pair . 4 . The codon properties of a nucleic acid base in messenger RNA can be predicted on the basis of its specificity in polynucleotide interactions . There seems to be no evidence for the participation of protein topological sites in the control of the specificity of codon-anticodon interactions in translation.

Eur J Biochem, 1977 Jan 3, 72(1), 117 - 25
Interactions of yeast tRNAPhe with ribosomes from yeast and Escherichia coli . A fluorescence spectroscopic study; Robertson JM et al.; The interaction of ethidium-labeled tRNAPhe from yeast with ribosomes from yeast and Escherichia coli was studied by stead-state measurements of fluorescence intensity and polarization . The ethidium label was covalently inserted into either the anticodon or the dihydrouridine loop of the tRNA . The codon-independent formation of a tRNA-ribosome complex led to only a moderate increase of the observed fluorescence polarization indicating a considerable internal mobility of the labeled parts of the tRNA molecule in the ribosome complex . When the ribosome complex was formed in the presence of poly(U), the probes both in the dihydrouridine loop and in the anticodon loop were strongly immobilized, the latter exhibiting a substantial increase in fluorescence intensity . A smaller intensity change was observed when E . coli ribosomes were used, although the extent of immobilization was found to be similar in this case . Competition experiments with non-labeled tRNAPhe showed that the labeled tRNAPheEtd was readily released from the complex with yeast ribosomes when poly(U) was absent, whereas in the presence of poly(U) it was bound practically irreversibly . The finding that the mobility of a probe in the dihydrouridine loop is affected by the codon-anticodon interaction on the ribosome suggests a conformational change of the ribosome-bound tRNA which may involve opening of the tertiary structure interactions between the dihydrouridine and the TpsiC loop.

Biochim Biophys Acta, 1977 Jan 3, 474(1), 61 - 8
The restriction endonuclease cleavage map of rat liver mitochondrial DNA; Kroon AM et al.; Mitochondrial DNA from rat liver contains six sites for cleavage by the restriction endonucleases Hind III and EcoRI . A large stretch of DNA, comprising about 40% of the mitochondrial genome is not cleaved by either of the enzymes; eight cleavage sites are located on a DNA stretch of 35% of the genome length suggestive of an unequal distribution of the A - T baspairs over the molecule . The number of Hind III and Eco R I fragments is much higher than reported for other mammalian mitochondrial DNAs up to now.

Biochim Biophys Acta, 1977 Jan 3, 474(1), 30 - 43
Induction of lesions in deoxyribonucleic acid by low molecular weight substances from normal and colicin E2-treated cells of Escherichia coli; Maeda A; A fraction containing a variety of low molecular weight substances was extracted into 80% aqueous acetone from both a colicin E2-treated cell culture of Escherichia coli and an untreated one . The extract was divided into five fractions by Sephadex G15 chromatography . One of them, Fraction B, was separated into three subfractions by Sephadex G10 chromatography . Two subfractions, Fraction BI and Fraction BII, were further fractionated by several chromatographic systems . DNA was incubated with an aliquot from each of these fractions and was then analyzed by sedimentation in an alkaline sucrose density gradient . The activity which caused a decrease in the sedimentation coefficient of the DNA was found in some of these fractions . The activity from colicin E2-treated cells was compared with that from untreated ones . It was revealed that colicin E2 induces some increases in the activity toward DNA in one of the subfractions, Fraction BI, and also causes the appearance of a new species in another fraction, Fraction BII, which potentiates the activity in Fraction BI . These colicin E2-induced changes appeared at 5 min after the addition of colicin E2 . The possible significance of such reactions for the action of colicin E2 are discussed.

Eur J Biochem, 1977 Jan 3, 72(1), 127 - 35
Glucose effect in tgl mutant of Escherichia col K12 defective in methyl-alpha-D-glucoside transport; Erlagaeva RS et al.; 1 . The dependence of the rate of accumulation of methyl-alpha-D-glucoside on its extracellular concentration was studied in the tgl mutant of Escherichia coli K12, isolated earlier . It has been shown that the kinetics of methyl-alpha-D-glucoside transport differ sharply from those in wild-type bacteria . 2 . The beta-galactosidase synthesis in tgl strain is much less sensitive both to permanent and transient glucose catabolite repression . The level of cyclic AMP in mutant cells under the conditions of glucose catabolite repression is several times higher than in the parent strain . 3 . The tgl mutation does not affect the manifestation of catabolite inhibition and inducer exclusion with glucose . 4 . The data obtained are discussed in the light of a hypothesis concerning the existence of two sites, binding and pecific enzyme II of the phosphoenolpyruvate-dependent phosphotransferase system . The tgl mutation alters the first site, and the second one is damaged by the pgt mutation . 5 . It is suggested that the products of the tgl and gpt genes are necessary for the manifestation of the phenomena of glucose permanent and transient repression . The effects of catabolite inhibition and inducer exclusion are realized irrespective of the existence or absence of the tgl product.

J Biomed Mater Res, 1977 Jan, 11(1), 125 - 36
Perfusion trials with a collagen-immobilized enzyme in an extracorporeal reactor: activity, stability, and biocompatibility; Olanoff LS et al.; This paper is concerned with the evaluation of the in vivo performance characteristics of reconstituted bovine collagen as an insoluble carrier matrix fro therapeutic enzymes . The enzyme that was chosen as a model for this evaluation was E . coli L-asparaginase, which has been widely investigated as a soluble chemotherapeutic agent for the treatment of acute lymphocytic leukemia in humans (Oettgen et al., Cancer Res., 27, 2619, 1967 ; Beard et al., Brit . Med . J., 1, 191, 1970; Ohmuma et al., Cancer Res., 30, 2297, 1970) . The results presented here were obtained from perfusion trials with a collagen-asparaginase reactor incorporated into an extracorporeal circuit attached to the vascular systems of healthy mongrel dogs . A series of 1-2 hr perfusions were conducted with a single collagen-asparaginase membrane over a period of 4 months . Serum asparagine levels were reduced by more than 98% after 15-30 min perfusion time . Red blood cell (RBC), hemoglobin, hematocrit, and fibrinogen values remained constant during each perfusion . An average decrease of 48% in white blood cell (WBC) and 24% in platelet levels was observed, but these values began to rise slowly even before cessation of the perfusion . No serious toxic or antigenic reactions or mechanical or clotting difficulties were observed . In vitro activity, when assayed between perfusions, remained constant over a period of 4 months of intermittent use and storage . The potential advantages of collagen-enzyme complexes for the administration of therapeutic enzymes is discussed.

Scand J Infect Dis, 1977, 9(1), 5 - 7
The NBT (Nitroblue Tetrazolium) activity of neutrophil granulocytes in patients with influenza A infection; Jarstrand C; The NBT activity of granulocytes from 11 influenza patients was determined during the acute stage of the disease and 6-8 weeks after recovery . The NBT activity was generally higher during influenza than after recovery . In the presence as well as in the absence of the patient's serum the differences were significant both without and with Escherichia coli stimulation.

Hoppe Seylers Z Physiol Chem, 1977 Jan, 358(1), 69 - 78
The influence of glycosaminoglycans on the synthesis of polyphenylalanine by rat liver ribosomes; Gressner AM et al.; Of the natural glycosaminoglycans tested, only heparin was a potent inhibitor of poly (U)-directed polyphenylalanine synthesis by rat liver ribosomes (50% inhibition at 10 mug/ml) . A chemically oversulfated chondroitin sulfate was twice as effective, and another synthetic polyanion, sodium pentosan polysulfate was ten times more effective than heparin . Chondroitin-4,6-sulfate was inhibitory at very high concentrations (15 mg/ml) and heparan sulfate at concentrations above 100 mug/ml . The compounds interfere with the formation of ternary complex consisting of the ribosome, poly(U) and phenylalanyl-tRNA . The inhibitors prevented the attachment of the mRNA to the ribosome, probably by competition with poly(U) for the ribosomal binding site of mRNA . However, they were ineffective in doing so once phenylalanyl-tRNA has bound to the ribosomepoly(U) complex . Sucrose gradient analysis in presence of the inhibitors revealed a selective effect on the sedimentation of the small ribosomal subunit; the large subunit was unaltered . This effect, however, was dependent on the concentration of magnesium . In contrast to Escherichia coli ribosomes, no binding of the inhibitors to the particles could be demonstrated.

J Virol, 1977 Jan, 21(1), 24 - 34
Influenza virion transcriptase: synthesis in vitro of large, polyadenylic acid-containing complementary RNA; Plotch SJ et al.; The influenza virion transcriptase is capable of synthesizing in vitro complementary RNA (cRNA) that is similar in several characteristics to the cRNA synthesized in the infected cell, which is the viral mRNA . Most of the in vitro cRNA is large (approximately 2.5 X 10(5) to 10(6) daltons), similar in size to in vivo cRNA . The in vitro transcripts initiate in adenosine (A) or guanosine (G) at the 5' end, as also appears to be the case with in vivo cRNA (R.M . Krug et al., 1976) . The in vitro transcripts contain covalently linked polyadenylate {poly(A)} sequences, which are longer and more heterogeneous than the poly(A) sequences found on in vivo cRNA . The synthesis in vitro of cRNA with these characteristics requires both the proper divalent cation, Mg2+, and a specific dinulceside monophosphage (DNMP), ApG or GpG . These DNMPs stimulate cRNA synthesis about 100-fold in the presence of Mg2+ and act as primers to initiate RNA chains, as demonstrated by the fact that the 5'-phosphorylated derivatives of these DNMP's, 32pApG or 32pGpG, are incroporated at the 5' end of the product RNA . The RNA synthesized in vitro differs from in vivo cRNA in that neither capping nor methylation of the in vitro transcripts has been detected . The virion does contain a methylase activity, as shown by its ability to methylate exogenous methyl-deficient Escherichia coli tRNA.

J Lab Clin Med, 1977 Jan, 89(1), 135 - 46
Inhibition of some functions of polymorphonuclear leukocytes by in vitro zinc; Chvapil M et al.; In granulocytes isolated by dextran sedimentation from dog blood, the O2 consumption, phagocytosis of yeast particles, and E . coli killing were tested in Tris-guffered saline medium with additions of Zn++, Mg++, and other divalent cations and in the presence or absence of plasma . Zn++ inhibited all three cell functions in a concentration-related manner only in the presence of 1.2 mM Mg++ . Without Mg++ in the medium the lower concentrations of Zn++ (17 to 67 muM) were stimulatory; 83 muM Zn++ concentration was inhibitory . A close association was found between the inhibitory effect of Zn++ and the actual content of zinc in the cell: (1) the uptake of zinc from the medium was minimal during the first minute, where no Zn++ effect on cell functions was manifest, (2) when zinc-loaded cells with inhibited activity were washed and reincubated for at least 15 minutes in zinc-free medium, almost 95 per cent of the zinc was washed out and cell activity was normalized . This indicated reversibility of the zinc effect, (3) in the presence of increasing concentrations of autologous plasma in the medium, the effect of zinc was proportionally less pronounced and at the same time uptake of zinc by cells was decreased . Of the six divalent cations studied at 50 muM concentration and in the presence of Mg++, only Zn++ was inhibitory, Se and Co were inactive, and Mn and Cu stimulated O2 consumption of latex-activated granulocytes . We conclude that zinc ions, in the presence of Mg++ in the medium, inhibit various functions of dog peripheral granulocytes and this effect is closely associated with zinc uptake by the cells . The effect is reversible and specific for this metal.

Cancer Biochem Biophys, 1977, 2(1), 43 - 50
The effectiveness of clinically useful antitumor agents as inhbitors of RNA polymerases; Hill BT; Many clinically useful antitumor agents effective inhibitors of both the exogenous Escherichia coli DNA-dependent RNA polymerases in vitro and the endogenous polymerase in mammalian cultured cells . The drug concentrations required for this inhibition are comparable to those achievable plasma levels in man for Actinomycin D, Adriamycin, 5-Fluorouracil, ICRF 159, Melphalan, Methotrexate and Vincristine . Therefore before the mechanisms of these drugs can be fully understood inhibition of RNA synthesis and its implications in the continued survival and replication of cells must be considered . Although chemotherapeutic agents have generally been considered to exert their cytotoxic affects by directly interfering with DNA metabolism or by inhibiting enzymatic pathways in purine and pyrimidine nucleotide metabolism, these data emphasize that this is an oversimplication . Most agents have multiple effective target sites within the cell and the primary cytotoxic events responsible for their clinical effectiveness remain to be elucidated.

Z Allg Mikrobiol, 1977, 17(7), 521 - 9
{Effect of temperature on the transcription of T3 DNA b y T3-specific RNA polymerase in cell-free extracts of Escherichia coli CRT266}; Musielski H et al.; Cell free extracts were prepared from E . coli CRT266 9 min after infection with T3 phages . RNA synthesis in these extracts is almost entirely due to T3 RNA polymerase . The inactivation of T3 RNA polymerase in these extracts proceeds rapidly at 42 degrees C . 90% of the activity is lost within 10 min at this temperature . Under conditions where the formation of a stable initiation complex with T3 DNA is possible, i.e., in the presence of GPT, APT, and UTP the T3 RNA polymerase becomes protected against heat inactivation losing only )0% of its activity during an exposure to 42 degrees C for 10 min . Studies on the time course of RNA synthesis have shown that reinitiation is still possible at 37 degrees C and 42 degrees C . At 44 degrees C, however, RNA synthesis stops abruptly after 3 min indicating that reinitiation does no longer take place . The elongation of already initiated T3 RNA chains is rather resistant to heat . At 44 degrees C the same elongation rates are observed as at 37 degrees C and 42 degrees C, respectively.

J Hyg Epidemiol Microbiol Immunol, 1977, 21(3), 261 - 70
Purification of mouse cell interferon induced by isotopically labelled double-stranded f2 phage RNA; Taborsky I et al.; The dynamics of interferon formation by an established cell line of mouse fibroblast (L cells) and by mouse peritoneal leukocytes induced by double-stranded RNA extracted from E . coli f2 phage is described . The L cells produced interferon at a lower rate, the maximum values were obtained at 12 to 20 hours after induction, and the production was ultimately dependent on the established cell line used and on the presence of DEAE-dextran during induction . The mouse peritoneal leukocytes (MPL), on the other hand, did not require DEAE-dextran and the maximum of interferon production was reached between 6 and 12 hours after induction . Both the L cell- and the MPL-interferons were purified and concentrated so that the final specific biologic activity was 100-to 300-fold higher than that of the initial preparations (1 to 5 X 10(6) interferon units per mg protein) . Polyacrylamide gel electrophoresis showed similar migration profiles for the preparations of both interferons . The smaller part of the activity was situated in a broader, slow-moving peak and the greater part formed a sharp, high and fast-moving peak . Using 3H uridine-labelled f2 ds-RNA for induction of interferon it was found that one of the radioactivity zones coincided with the fast-moving activity peak of the purified and concentrated interferon.

Arch Geschwulstforsch, 1977, 47(6), 567 - 80
{The significance of in-vitro tests with respect to testing of substances for carcinogenic activities (author's transl)}; Schramm T et al.; The actual possibilities to test chemical substances for carcinogenic activities are critically assessed . Short-term-tests are especially discussed . By these tests--now utilized for screening of chemicals--specific biological activities can be determined, which correlate with carcinogenic effects in vivo . The phase of checking and improving the vitro-tests is not yet finished with regard to the rate of correlation of the results from those tests and the results from long-term experiments in animals as well as from clinical and epidemiological human data . Parallel to this investigations, results from long-term-tests should be critically evaluated, because the experimental induction of tumors in animals is up to now the only way to prove carcinogenic activity of a chemical . Short-term-tests should be utilized as screening methods for the selection of suspicious substances, which should or must be further tested in long-term animal experiments . At present results from short-term-tests are not sufficient to classify a substance as a carcinogen or a non-carcinogen . Certain short-term-tests can and will get significance for the evaluation of the carcinogenic risk of chemicals to man when comparing the metabolism of carcinogens in vitro using enzymatic systems of a series of mammalians including man.

J Supramol Struct, 1977, 7(1), 29 - 35
On the rate limiting step in downhill transport via the LacY permease of Escherichia coli; Rotman B; Strains of Escherichia coli K12 were constructed for the specific purpose of evaluating the inducibility of the influx mechanism controlled by the lacY gene . These strains are heteromerodiploids characterized by a high and relatively constant level of beta-D-galactosidase which is not affected significantly by induction of the Lac operon . These properties were obtained by introducing episomal lacI+,Oc,Z+,Y-genes into the cells . In these merodiploids the rate of o-nitrophenyl-beta-D-galactopyranoside (ONPG) hydrolysis of extracted cells is 50-times that of intact cells . This difference indicates that the rate limiting step in the ONPG hydrolysis by intact cells is influx . Using a set of merodiploids with and without the LacY transport system, we were able to demonstrate a specific induction of ONPG influx . However, the increase in influx due to induction was only 3.5-fold as compared to the 40-fold increase observed when the LacY permease was measured by intracellular accumulation of {14C}TMG.

Adv Exp Med Biol, 1977, 86A, 441 - 71
Chemical modificiation of collagen and the effects on enzyme-binding: mechanistic considerations; Giacin JR et al.; The effect of structural modification on the enzyme-binding capacity of collagen has been studied using beta-galactosidase (E . coli K12) immobilized to collagen membrane by the impregnation procedure . The apparent steady-state activities of the resultant collagen-enzyme complexes were determined as a means of evaluating the enzyme-binding capacity of the modified collagen . In addition, the amount of enzymic protein bound to the collagen support was determined by the tryptophan content of the complex . The tertiary structure of the collage matrix was modified by cross-linking with the difunctional reagent, glutaraldehyde, and by aging in the dry state . Such structural modifications were found to markedly reduce the enzyme (beta-galactosidase) binding capacity of collagen films . The enzyme-binding capacity of the crosslinked collagen membrane was completely restored by proteolytic enzyme treatment of the aged film but only partly so for the glutaraldehyde treated films . Proteolytic enzymes used to treat a dispersion of collagen microfibrils prior to casting into a membrane also resulted in an increase in enzyme-binding . The effect of structural modification of collagen on enzyme-binding and the locus of enzyme attachment are discussed.

Genetika, 1977, 13(8), 1425 - 33
{Escherichia coli K-12 mutants capable of catabolizing purine nucleosides in the absence of purine nucleoside phosphorylase}; Kocharian ShM et al.; Strains of Escherichia coli K-12 defective in purine nucleoside phosphorylase (pup gene) formed on the medium with inosine as the source of carbon and energy phenotypical reversions for the ability of utilizing inosine as source of carbon or purines . The phenotypical suppression of the purine nucleoside phosphorylase deficiency is the result of the mutations (called pnd), which are mapped on the chromosome of E . coli beyond the region of the structural pup-gene location and have phenotypic manifestation distinct from that of pup+ allele: a) pnd mutants divide into some groups for the ability of utilizing several purine nucleosides, including xantosine that cannot be metabolized by pnd+ strains of E . coli; b) pnd mutations do not restore the ability of purine auxotrophs (pur) defective in purine nucleoside phosphorylase (pup) and adenine phosphoribosyltransferase (apt) to grow on the medium with adenine as the sole source of purines . Cell-free extracts of pnd mutants fail to degrade the guanine nucleosides in the absence of phosphate or arsenate ions . These data (and also the ability of pnd mutants to utilize both purine ribonucleosides and deoxyribonucleosides) seem to indicate that the activities induced by pnd mutations are phosphorylase activities.

Biochimie, 1977, 59(5-6), 463 - 72
Localisation of part of the binding sites of 30S ribosomal proteins S4 and S20 in a small uninterrupted fragment of 16S RNA; Barritault D et al.; Analyses of the T1 ribonuclease-alkaline phosphatase fingerprint of a continuous fragment of the 16S rRNA, 170-230 nucleotides long, isolated from the products of autodigestion of 30S ribosome subunits show that it contains a sequence near the 5'-phosphate terminus of intact 16S rRNA and corresponds to segment H'-M of this molecule as defined by Ehresmann et al {29} . Incubation of this fragment with total 30S ribosomal proteins under reconstitution conditions leads to the formation of a complex containing proteins S4, S20, and one or both of proteins S16 and S17 . The stoichiometry of these proteins in the complex is discussed.

Rev Interam Radiol, 1977 Jan, 2(1), 41 - 2
Unusual radiographic manifestations of cystic fibrosis; Haller JO et al.; The authors report 2 radiographic findings that have not previously been described in patients with cystic fibrosis: (1) the linear form of pneumatosis coli (2) large pancreatic concretions which resembled the pancreatic calcificaitons of hereditary pancreatitis . The patient with pancreatic calcification also had labile diabetes and episodes of ketoacidosis, unusual complications of cystic fibrosis.

Acta Haematol, 1977, 57(2), 74 - 80
A simplified one-step procedure for the simultaneous determination of complement receptor lymphocytes and lymphocytes with membrane-bound immunoglobulins; Winterleitner H et al.; A simple one-step procedure for the demonstration of complement receptor lymphocytes (CRL) with complement-coated bacteria (BC) as indicator particles is described . With this assay the percentage of CRL in normal peripheral blood ranged between 6 and 21% (mean 11%) . In a separately performed combined assay for lymphocytes with membrane-bound immunoglobulins (M-Ig) and lymphocytes, which form rosettes with complement-coated bacteria (BC-RFC), four different fractions of lymphocytes could be detected: (M-Ig+-BC+, M-Ig+-BC-,M-Ig--BC+, M-Ig--BC-) . These results suggest that the subpopulation of lymphocytes with complement receptor sites overlaps with, but is not totally identical with the lymphocyte subpopulation bearing Ig on the surface.

Lab Anim, 1977 Jan, 11(1), 29 - 34
The establishment of specified-pathogen-free marmosets, Callithrix jacchus; Hobbs KR et al.; The establishment of 3 specified-pathogen-free marmosets (Callithrix jacchus) during the period May 1969 to January 1973 is described . A brief history of the conventional breeding colony from which the animals were derived is given and hysterotomy and hand-rearing techniques are described.

Infect Immun, 1977 Jan, 15(1), 272 - 9
K99 surface antigen of Escherichia coli: purification and partial characterization; Isaacson RE; K99, a presumed colonizing factor of enterotoxigenic Escherichia coli of calf origin, has been purified . K99 was removed from K99+ bacteria by salt extraction and subsequently purified by ammonium sulfate precipitation and column chromatography on diethylaminoethyl-Sephadex . The purified material was homogenous in size, having an s20,w of 13 to 15 S . It was composed of two subunits: a major component with a molecular weight of 22,500 and a minor component of 29,500 . When observed in the electron microscope, K99 appeared to be rod-shaped, with a strong tendency for self-aggregation . At concentrations where aggregation was minimized, individual rods were observed with diameters of 8.4 nm and mean lengths of 130 nm . Based on the subunit structure, exterior location, and rod-like shape of K99, it is concluded that K99 is a pilus or pilus-like structure . Chemically, K99 is composed primarily of protein and has an isoelectric point of greater than 10 . Purified K99 did not hemagglutinate guinea pig erythrocytes.

Chemotherapy, 1977, 23 Suppl 1, 25 - 36
Susceptibility to fosfomycin of hospital strains isolated in Nantes (France) . Frequency of mutation to resistance; Courtieu AL et al.; Susceptibility of 760 bacterial isolates to fosfomycin has been determined by the agar dilution method . The MICs of 364 strains have been determined by comparison of agar alone and agar plus glucose-6-phosphate . This later enhances the activity of fosfomycin . Lastly, we studied frequency of mutation toward resistance for 109 susceptible strains . We obtained 88 stable mutants.

J Supramol Struct, 1977, 7(3-4), 463 - 80
The molecular mechanism of dicarboxylic acid transport in Escherichia coli K 12; Lo TC; It is the purpose of this communication to review the properties of the dicarboxylic acid transport system in Escherichia coli K 12, in particular the role of various dicarboxylate transport proteins, and the disposition of these components in the cytoplasmic membrane . The dicarboxylate transport system is an active process and is responsible for the uptake of succinate, fumarate, and malate . Membrane vesicles prepared from the EDTA, lysozyme, and osmotic shock treatment take up the dicarboxylic acids in the presence of an electron donor . Genetic analysis of various transport mutants indicates that there is only one dicarboxylic acid transport system present in Escherichia coli K 12, and that at least 3 genes, designated cbt, dct A, and dct B, are involved in this transport system . The products corresponding to the 3 genes are: a periplasmic binding protein (PBP) specified by cbt, and 2 membrane integral proteins, SBP 1 and SBP 2, specified by dct B and dct A, respectively . Components SBP 1 and SBP 2 appear to be exposed on both the inner and outer surfaces of the membrane, and lie in close proximity to each other . The substrate recognition sites of SBP 2 and SBP 1 are exposed on the outer and inner surfaces of the membrane respectively . The data presently available suggest that dicarboxylic acids may be translocated across the membrane via a transport channel . A tentative working model on the mechanism of translocation of dicarboxylic acids across the cell envelope by the periplasmic binding protein, and the 2 membrane carrier proteins is presented.

Genetika, 1977, 13(11), 1988 - 96
{Role of the product of recB-gene in the thymine-less death and characteristics of this phenomenon in a thy-recB--mutant of Escherichia coli K-12}; Aizenberg OA et al.; Thymine requiring mutants of rec+ and recB- Escherichia coli strains have been tested for their response to thymine deprivation . Exonuclease V-deficient mutant is less sensitive to thymine deprivation than the wild type strain, because there is no lag period at thymineless death of recB- thy- cells . However, the mechanism of thymineless death of thy- rec+ and thy- recB- cells may be different . Two types of thymineless death are proposed to exist . The first type is due to DNA primary structure damages (single-strand breaks or gaps), accompanied by DNA degradation . The restoration of the balance disturbed by the thymine deprivation between DNA and protein synthesis rates by their balanced inhibition promotes a complete repair of structural damages in DNA and prevents the death of rec+ cells . The second type of thymineless death is not linked with the formation of DNA damages, and this is observed in recB- thy- mutant, defective in exonuclease V.

Physiol Chem Phys, 1977, 9(4-5), 399 - 403
Biological ion exchanger resins: XI . Actin in Escherichia coli; Minkoff L et al.; The 45,000 molecular weight component of an "actin-like" fraction (A-L fraction) from E . coli is identified as actin . Passage of skeletal muscle myosin through the A-L fraction specifically removes the 45,000 molecular weight band visible on electrophoresis prior to passage . Examination of the myosin after passage exhibits a new band on electrophoresis at 45,000 molecular weight.

Genetika, 1977, 13(10), 1821 - 30
{Mutations of resistance to 2,6-diaminopurine and 6-methylpurine that affect adenine phosphoribosyltransferase in Escherichia coli K-12}; Kocharian ShM et al.; Independently obtained mutations (apt) of resistance to DAP (2,6-diaminopurine) and MP (6-methylpurine), that affect adenine phosphoribosyltransferase (APRT) in Escherichia coli, are different in their effect on the conversion of several substrates of APRT, such as DAP, MP, MAP (6-methylaminopurine) and adenine, to their nucleotide derivatives . Most of mutants were resistant to DAP and MP, unable to utilize MAP (as purine source) and differed in their ability to uptake adenine from the medium . Among the mutants capable to utilize adenine the following types are found: (1) resistant to DAP and MP, but capable of utilizing MAP, and (2) resistant to DAP, capable of utilizing MAP, but sensitive to MP . The gene apt encoding APRT is located between genes proC and purE; the frequency of cotransduction between proC and several apt mutations is found to be 1.7--2% and purE-apt--to be 5--10.8% . Mutations apt block up the ability of purine-dependent (pur) bacteria lacking purine nucleoside phosphorylase (pup) to use purine ribonucleosides as purine sources . The degree of that blocking depends on the ability of apt mutants to convert adenine to AMP via APRT . These observations confirm our previous data, that the ability of pur pup mutants to use purine ribonucleosides depends on the activity of APRT.

Genetika, 1977, 13(10), 1809 - 20
{Preferred secondary attachment site of prophage phi80 on Escherichia coli K-12 chromosome}; Il'ina TS et al.; The integration frequency of phage att80 immlambdac1857 into the chromosome of a mutant strain H47 Escherichia coli K-12 deleted for the normal prophage insertion site is found to be about 20-fold decreased as compared with its integration into the wild type strain . The most of the resulting lysogens contain the prophage at the secondary attachment site of the mutant bacterial chromosome which is preferentially utilized for prophage insertion . This attachment site (att80-II) is located close to his-genes on the chromosome of H47 strain . Prophage curing procedure of such abnormal lysogens results in the appearance of rare auxotrophic heat-resistant survivors with the His- phenotype . In some cases the prophage insertion can induce an inversion of a neighbouring genetic region . Such lysogens contain the purC gene near prophage located at the att80-II site, and after curing they segregate the heat-resistant His- and Pur- colonies.

Genetika, 1977, 13(1), 125 - 31
{Mechanism of the mutagenic action of the decay of incorporated phosphorus-32}; Pluciennik H; The experimental material concerning that physico-chemical consequences of 32P decay in the molecular structure of DNA, their reparation mechanism as well, and resulting mutagenic effects have been analysed . The reparation of the single-strand break of the DNA chain does not cause the changes of microdeletion and microinsertion type but instead of the changes observed are of the nucleic bases conversion type . It is concluded that the mutations caused by the decay of 32P incorporated appear as a result of errors in the selection of nucleic bases during the reparative replication of the non-conservative type.

Acta Biol Med Ger, 1977, 36(7-8), 961 - 6
{Action of respiratory inhibitors on the electron transport system of Escherichia coli}; Schewe T et al.; Bacteria of two strains of Escherichia coli (Q13 and MRE 600) were disintegrated by aluminium oxide . The influence of the respiratory inhibitors RF (a protein from reticulocytes), carboxin, Dexon (fungicides), thenoylftrifluoroacetone (TTFA), rotenone, antimycin A, myristic acid and monolaurin was tested on the succinate oxidase and the NADH oxidase system, respectively, of the membrane preparation obtained in this way as well as on the NADH oxidase activity of the cytosol . Among the inhibitors listed, only TTFA (5mM) inhibited the succinate oxidase system and Dexon (10 miconr), monolaurin (100 micron) and myristic acid (100 micron) inhibited the NADH oxidase system of the membranes . KCN (10 micron) inhibited both NADH oxidase systems . The inhibitory effects by monolaurin and myristic acid were prevent by human serum albumin and were markedly weaker than those on beef heart mitochondrial particles under similar conditions . The results argue for a divergent structure of the iron-sulphur proteins in the dehydrogenase regions of the electron transport system in comparison with animal and plant mitochondria and, moreover, confirm the specificity of RF and carboxin as well as the nature of Dexon as a group reagent on pyridine nucleotide dependent flavin enzymes.

Microbios, 1977, 18(72), 123 - 30
Preparation and stability of mureinoplasts of Escherichia coli; Gorman SP et al.; A peptidoglycan bounded form termed a mureinoplast was prepared from cells of Escherichia coli and the stability of this was examined in various suspending media . True protoplasts were subsequently formed from mureinoplasts.

Acta Chir Scand, 1977, 143(7-8), 473 - 7
Effect of prophylactic systemic administration of cephalothin in colorectal surgery; Kjellgren K et al.; The effect of standardized prophylactic treatment with systemically administered cephalothin (Keflin) was studied in a series of 120 consecutive patients in whom elective colorectal surgery was planned . The patients were divided by random selection into one treatment group and one control group . The same mechanical cleansing with cathartics and tap water enemas was performed in both groups . The patients in the treatment group received intravenously 2 g cephalothin 2 hours prior to the operation, 2 g during the operation and then 2 g every 6th hour during 4 days . 14 cases were excluded for various reasons . In 19 cases only minor operations were performed, such as laparotomy with or without simultaneous colostomy . The overall frequency of infections was 17.5% in the treatment group and 53.1% in the control group . In the 87 cases undergoing major operations, infections were registered in 17.4% of the treated patients and 58.5% of the control patients . The difference is highly significant (p less than 0.001) in both cases . Escherichia coli was present in about 70% of the infections, often together with other aerobic or anaerobic organisms.

Int Urol Nephrol, 1977, 9(3), 249 - 54
Malacoplakia of testis; Rinaudo P et al.; A case of malacoplakia of testis with a typical clinical course, related to urogenital E . coli infection is presented . By means of electron microscopy, we have identified several forms of Michaelis-Gutmann bodies within the lesion . X-ray spectral analysis revealed that these bodies contain large amounts of calcium, phosphate, sulfur, sodium and chloride . The pathogenesis of malacoplakia and the formation of Michaelis-Gutmann bodies is shortly discussed.

Gene, 1977, 2(3-4), 159 - 72
ColE1 cloning of a ribosomal RNA promoter region from lambdarifd18 by selection for lambda integration and excision functions; Glaser G et al.; The expression of the ribosomal RNA gene carried by the lambda transducing phage lambdarifd18 is shown to be subject to stringent amino acid control . lambdarifd18 DNA was digested with endonuclease EcoRI and ligated to similarly restricted ColE1 plasmid DNA . Selection for expression of lambda integration and excision gene activity carried by the same DNA fragment results in cloning of the promoter proximal portion of the 16S ribosomal RNA gene . The resulting chemera expresses lambda integration and excision functions as well as encoding the promoter proximal half of a 16S ribosomal RNA gene.

Gene, 1977, 2(2), 75 - 93
Construction and characterization of new cloning vehicles . I . Ampicillin-resistant derivatives of the plasmid pMB9; Bolivar F et al.; In vitro recombination via restriction endonucleases and the in vivo genetic translocation of the Ap resistance (Apr) gene resulted in the construction of a new cloning vehicle, the plasmid pBR313 . This vector was derived from a ColE1-like plasmid and, while it does not produce colicon E1, it still retains colicin E1 immunity . The Apr and tetracycline resistance (Tcr) markers carried in pBR313 were derived from the ampicillin transposon (TnA) of pRSF2124 and pSC101 respectively . During the construction of pBR313, the TnA component was altered and the Apr gene in pBR313 can no longer be translocated . This plasmid has a molecular weight of 5.8 Mdalton and has been characterized using thirteen restriction enzymes, six of which (EcoRI, SmaI, HpaI, HindIII, BamHI and SalI) cleave the plasmid at unique restriction sites . This allows the molecular cloning of DNA fragments generated by these six enzymes . The restriction sites for the latter three enzymes, HindIII, BamHI and SalI, are located in the Tcr gene(s) . Cloning DNA fragments into these sites alters the expression of the Tcr mechanisms thus providing a selection for cells carrying recombinant plasmid molecules . An enrichment method for AprTcS cells carrying recombinant plasmid molecules is described.

Biochimie, 1977, 59(11-12), 877 - 84
{Characterization of the membrane attached to the folded chromosome isolated from Escherichia coli}; Lacombe C et al.; Phospholipid analysis of the membranes associated with fast sedimenting folded chromosomes prepared by lysis of E . coli CR 34 shows that both inner and outer membranes are parts of the complex, in proportions not very different from that found in the whole bacteria . During the preparation of the folded chromosomes, the most recently synthesized molecules of phosphatidylglycerol and phosphatidylethanoamine are more sensitive to solubilisation, particularly those from the cytoplasmic membrane . Identification of a dominant fraction, the outer membrane, in some complexes, results from a preferential solubilization of the inner membrane . These results do not favor any specific association between the folded chromosome and the membranes.

Ann Rech Vet, 1977, 8(3), 319 - 25
Detecting enteropathogenic Escherichia coli strains of porcine origin . 1 . Correlations between O and K antigens and the enterotoxin production in strains isolated from the newborn piglet; Renault L et al.; A study of enterotoxin production by means of biological tests (Y1 adrenal cells and suckling mice) using 67 Escherichia coli strains responsible for diarrhea in newborn piglets, confirmed the advantages of these methods and demonstrated the correlation between antigenic specificity and enterotoxin production . In particular the presence of capsular antigen K 88 is related to the thermolabile (LT) fraction of the enterotoxin in 73.9 % of the enteropathogenic strains studied.

Vet Med Nauki, 1977, 14(9), 67 - 71
{Immunodepressive activity of cell fractions of Escherichia coli O138:K81:H19}; Ruskova M; A soluble cell fraction (cytosol), an O-antigen (endotoxin), and an unsoluble cell ingredient were isolated from a 24-hour culture of Escherichia coli O138:K81:H19 . Their immunosuppressive action was determined by using the tuberculin test and the survival rate of the allographts . It was found that: 1 . Cytosol appears to be a slightly toxic preparation with well expressed immunosuppressive action . 2 . The endotoxin is highly toxic, producing the same effect as cytosol . 3 . The unsoluble cell ingredient is a comparatively toxic preparation, producing an undependable immunosuppressive effect . Discussed is the mechanism of the immunosuppressive activity of the investigated subcellular fractions . It believed to be due to a certain injurious action on the function of the T-cells.

Mutat Res, 1977, 47(1), 1 - 52
Caffeine; Timson J; Most of the population of the world is exposed to caffeine to a greater or lesser extent since it occurs in a number of plants used in the preparation of widely consumed drinks, and has in addition a limited therapeutic use . Chromosomal abnormalities are induced by caffeine in both plant cells and in mammalian cells in culture and it also has some anti-mitotic activity . DNA-repair processes sensitive to caffeine have been demonstrated in a number of cell systems and it has been shown to affect a wide range of other cellular processes . Caffeine has potent mutagenic effects in Escherichia coli and other micro-organisms both when acting alone and in combination with other mutagens . However its mutagenic activity in Drosophila has been disputed and the available evidence suggests that it is neither mutagenic in mammals nor synergistic with other mutagens although at very high doses it appears to have some teratogenic activity in mammals.

Biochimie, 1977, 59(10), 857 - 9
{Biosynthesis of thiazole from thiamine in Escherichia coli}; Estramareix B et al.; The incorporation into the thiazole moiety of thiamine of several labeled compounds has been studied on short time incubations of washed-cells suspensions . No incorporation of radioactivity from {G-14C} methionine was found in a mutant auxotrophic for methionine . No radioactivity was incorporated from {U-14C} aspartate or from {U-14C} serine . The incorporation of 35S from sulphate was lowered by cysteine or glutathione but was unaffected by methionine or homocystine . Although the synthesis of thiazole is dependent on methionine, neither the sulphur atom nor the carbon chain of thiazole originate from methonine in E . coli . No carbon originates from cysteine which is the likely direct donor of sulphur.

Biochimie, 1977, 59(10), 785 - 8
Rotational diffusion of Escherichia coli ribosomes . II . - Ribosome attachment to polyurydilic acid; Pochon F et al.; Ribosome attachment to poly(U) has been studied by following the rotational diffusion of polyribosomes in solution . On the average, 13-17 and 50 nucleotides are found to be associated with 30S and 70S ribosome respectively . For an equal length of poly(U), the number of particles in a 30S polysome is four times that in a 70S polysome . The results are consistent with a structure of the polysome in which individual ribosomes are in close contact.

Biochimie, 1977, 59(10), 779 - 84
Rotational diffusion of Escherichia coli ribosomes . I . - Free 70 S, 50 S and 30 S particles; Amand B et al.; The rotational brownian diffusion of Escherichia coli ribosomes has been studied by following the transient dichroism generated by optical excitation of a covalent probe into its triplet state . The induced absorption anisotropy decays exponentially with characteristic correlation times: 2.5 microseconds, 1.6 microseconds and 1.1 microseconds for the 70S ribosome and the 50S and 30S subparticles respectively . The corresponding Stokes radii are in the same order, 133 A, 115 A and 103 A . The hydrodynamic properties are discussed in terms of an ellipsoidal shape of the ribosome particles.

Acta Microbiol Acad Sci Hung, 1977, 24(3), 253 - 60
Surveillance of R-plasmids; Rische H et al.; The surveillance of R-plasmids consists of: (1.) Ecological and epidemiological investigations . (1.1.) Prevalence of R-plasmids in pathogenic and apathogenic bacteria occurring in the biotic environment (man, animal); in the abiotic environment (sewage, food, feed); under high selection pressure (hospital, animal production, plant production) . (2.) Biological investigations . (2.1.) Genetic properties of R-plasmids: (2.2.) Plasmid induced variations of the properties of the host bacteria (virulence, phage pattern, antigenic pattern, serological properties) . The problems resulting from plasmid-mediated drug resistance call for a strict chemotherapeutic drug policy with the regard to ecological processes.

Acta Microbiol Acad Sci Hung, 1977, 24(3), 247 - 52
Influence of hypothermia on the generalized Shwartzman reaction; Szilagyi T et al.; In normothermic rabbits the generalized Shwartzman reaction can usually be elicited by two intravenous injections of endotoxin spaced 24 hr apart . The reaction could be prevented by cooling the rabbits . Hypothermia is effective only at the time of the second injection . The protective effect can clearly be demonstrated by gross and histologic examination . The possible mechanism of the protective action of hypothermia is discussed.

Acta Microbiol Acad Sci Hung, 1977, 24(3), 221 - 36
Pathogenic effect of enterotoxigenic Escherichia coli and Escherichia coli causing infantile diarrhoea; Polotsky YE et al.; Macroscopic, light and electron microscopic alterations in ligated rabbit intestinal loops challenged with five standard enterotoxigenic Escherichia coli (ETEC) and twenty-three enteropathogenic E . coli (EEC-I) strains, freshly isolated from infantile enteritis cases, were investigated . Only two O26 : K60 : H11 strains produced enterotoxin . Their living cultures, sterile filtrates of the fluid medium and ultrasonic lysates of the bacteria resulted in pronounced hypersecretion of the intestinal epithelium followed by fluid accumulation and loop dilatation . These two E . coli strains, similarly as the other loop-negative EEC-I strains, were able to penetrate into the intestinal epithelium . In contrast to the standard ETEC strains, the EEC-I bacteria, adhering to the brush border, intruded into the microvilli, multiplied on the outer epithelial cell membrane making close contact with it and, causing, shedding of microvilli, penetrated into enterocytes becoming enclosed in membrane-bound phagosome-like vacuoles, appeared in the lamina propria and elicited mild focal polymorphonuclear infiltration.

Acta Microbiol Acad Sci Hung, 1977, 24(2), 149 - 55
Distribution of 32P-labelled endotoxin in the frog; Szilagyi T et al.; Distribution and elimination of 32P-labelled endotoxin were studied in normal frogs and in frogs pretreated with a high dose of unlabelled endotoxin 24 hr previously . Like in other animals, the spleen and the liver of the frogs were found the most active R.E.S . organs . The alimentary tract too exhibited considerable R.E.S . activity . Pretreatment with unlabelled endotoxin resulted in a decrease of 32P-endotoxin uptake by the liver, the spleen and the alimentary tract . Evidence was obtained that the well-known effects of endotoxin on the R.E.S . of the mammals can be demonstrated in the frog as well.

J Supramol Struct, 1977, 7(2), 191 - 204
Prediction for secondary structures of ten proteins from the 50S subunit of the Escherichia coli ribosome; Dzionara M et al.; Predictions of the secondary structures of the following 10 proteins from the large subunit of the E . coli ribosome were made using their known amino acid sequences: L6, L16, L19, L27, L28, L30, L31, L32, L33, and L34 . The predictions were made according to 4 different methods and the results for each protein are presented as diagrams indicating the conformational states, helix, extended structure, turn, and random coil, of each residue . From these diagrams, regions of highly probable secondary structure for the proteins are calculated . Estimates are made of the maximum possible lengths of the proteins in order to correlate these with the results obtained from antibody binding sites in the 50S subunit as determined by electron microscopy.

Infection, 1977, 5(4), 232 - 5
Daily single-dose gentamicin therapy in experimental pyelonephritis; Hatala M et al.; The therapeutic efficacy of gentamicin given once or three times a day was compared in a model of experimental renal infection in rats . The same amount of gentamicin given either in a single injection or three injections a day produced no statistically significant difference in the treatment of incipient infection . The effect of this mode of administration on advanced infection depended on the length of the therapy . After five days, administration of the same dose given in a single injection or three injections did not result in significant differences . After ten days the therapy proved more effective when gentamicin was injected three times a day . In comparison a single daily dose, amounting to two thirds of the total dose when given three times a day every eight hours, revealed after five days of therapy a statistically significantly lower bacterial count in the kidney than three daily injections of gentamicin.

Genetika, 1977, 13(9), 1621 - 5
{Mutagenic effect of new chemical compounds . IV . Mutagenic effect of dialkylaminoethyl esters of 5,6-dihydro-7H-benz(c)carbazol-carboxylic acids}; Paronikian GM et al.; The mutagenic effect of dialkylaminoet hyl esters of 5,6-dihydro-7H-benz(c)carbazole-carboxylic acids on biochemical mutants (Escherichia coli P-678, Actinomyces rimosus 222) is found . Hydrochloride of diethylaminoethyl ester of 5,6-dihydro-7H-benz(c)carbazole-9-carboxylic acid, which induced reversible and direct mutations, proved to be the most active compound, its mutagenic activity exceeding considerably the activity of ethylene imine.

Circ Shock, 1977, 4(4), 387 - 95
Endotoxin-induced increased alveolar capillary membrane permeability; Fischer P et al.; In an attempt to define the effects of endotoxin on the permeability of the pulmonary alveolar capillary membrane (ACM) to a variety of substances {molecular weight (MW) varying from 60 to 69,000}, we studied the movement of specific molecular species from the pulmonary capillary blood to the saline-filled "alveolus," employing an in vivo dog lung model . Following endotoxin injection (2-2.5 mg/kg) baseline T1/2 values (time, in minutes, for 50% equilibration of the specific solute between the blood and the saline-filled lung) decreased as follows (compared to baseline values): urea (MW 60) - 42.5 +/- 24 to 21.3 +/- 18; sucrose (MW 360) - 201 +/- 72 to 76 +/- 53; 3,000 MW dextran - 1,275 +/- 746 to 686 +/- 433; 10,400 MW dextran - 1,871 +/- 845 to 1,052 +/- 630 (all p less than 0.05) . Neither 20,000 MW dextran nor albumin (MW 69,000) showed an increased permeability following endotoxin injection . Histamine analysis revealed a significant increase in all lung liquid samples post-endotoxin injection without a significant increase in blood histamine values . We conclude that, acutely (within 4 hr of injection), endotoxin causes an increase in permeability of the ACM for substances up to 10,400 MW . The role of histamine in this increased permeability remains controversial.

J Supramol Struct, 1977, 6(4), 495 - 502
The mechanism of sugar-dependent repression of synthesis of catabolic enzymes in Escherichia coli; Gonzalez JE et al.; Previous studies have indicated that the Escherichia coli adenylate cyclase (AC) activity is controlled by an interaction with the phosphoenolpyruvate (PEP): sugar phosphotransferase system (PTS) . A model for the regulation of AC involving the phosphorylation state of the PTS is described . Kinectic studies support the concept that the velocity of AC is determined by the opposing contributions of PEP-dependent phosphorylation (V1) and sugar-dependent dephosphorylation (V2) of the PTS proteins according to the expression percent VAC=100/{1 + (Max V2/Max V1)} . Physiological parameters influencing the rate of the PTS are discussed in the framework of their effects on cAMP metabolism . Factors that increase cellular concentration of PEP (and stimulate V1) appear to enhance AC activity while increases in extracellular sugar concentration (which stimulate V2) or internal levels of pyruvate (which inhibit V1) inhibit the activity of this enzyme.

J Supramol Struct, 1977, 6(3), 411 - 7
L-Arabinose transport and the L-arabinose binding protein of Escherichia coli; Hogg RW; The active accumulation of L-arabinose by arabinose induced cultures of Escherichia coli is mediated by 2 independent transport mechanisms . One, specified by the gene locus araE, is membrane bound and possesses a relatively "low affinity" . The other, specified in part by the genetic locus araF, contains as a functional component the L-arabinose binding protein and functions with a "high affinity" for the substrate . The L-arabinose binding protein has been purified, partially characterized, crystallized, and sequenced.

Vet Med Nauki, 1977, 14(5), 13 - 8
{Dynamics of agglutinins following vaccination against coli-bacteriosis in calves}; Penev PD; A bivalent vaccine, produced with strains Escherichia coli 078 and 0117 to control colibacteriosis in calves, was used to vaccinate experimentally 20 cows following up the agglutinin dynamics in the serum of calves born later on . It was found that the agglutinin titers of the 0 antibodies were lower than those of OK, and varied within the range of from 1:10 to 1:320, the titers of 1:20-1:40 values being prevalent . Highest level of titers was observed by the third day following birth . OK antibodies had titers that were 1-2 degrees higher, reaching their peak level as early as the 12-15 hour after birth . They persisted for a longer period in the blood serum of calves . The antibodies produced after vaccination were shown to be sensitive to 2-mercaptoethanol.

Vet Med Nauki, 1977, 14(4), 75 - 9
{Stomach ulcers in newborn swine}; Motovski A et al.; Stomach ulcers were established in sucking pigs, aged 1-3 days, on a pig-breeding farm . Thirty-two out of 40 pigs (spontaneously affected) of 5 primiparous sows died for 24 hours . Necropsy revealed ulcers on the mucous membrane of the stomach, varying in size and development of morphologic lesions . Histologic investigations were also carried out . Hemolytic Escherichia coli organisms were isolated form the same pigs, and were studied for pathogenicity and toxigenicity . An analysis was made of the etiologic factors contributive of stomach ulcers in newborn pigs.

Nephron, 1977, 19(6), 342 - 9
Effects of Escherichia coli lipopolysaccharide on renal glomerular and tubular adenylate cyclase; Baud L et al.; The effects of Escherichia coli lipopolysaccharide (LPS) on adenylate cyclase have been tested using renal tubular membranes and renal glomeruli isolated from rats . E . Coli LPS did not stimulate glomerular and tubular basal adenylate cyclase activity whereas it was an activator in the presence of fluoride . The effect of E . Coli LPS was immediate but was greater after 20 min preincubation . Maximum stimulation of both glomerular and tubular fluoride sensitive adenylate cyclase occurred at 125 microgram/ml of E . Coli LPS with an apparent Km (dose corresponding to 50% of maximum stimulation) of 30 microgram/ml . Above 125 microgram/ml there was a decrease in adenylate cyclase activity . E . Coli LPS produced an increase in the maximum velocity of both enzymes but did not affect their affinity for adenosine triphosphate . E . Coli LPS did not potentiate the effect of parathyroid hormone on glomerular and tubular adenylate cyclase . The lipid A moiety which is common to all LPS whatever the original strain gave results similar to those obtained with the entire LPS . This effect was specific and did not depend on the phospholipidic structure in general since no activation was obtained in the presence of phosphatidylserine.

Circ Shock, 1977, 4(3), 231 - 9
Leukocyte response and hypoglycemia in superlethal endotoxic shock; White GL et al.; This laboratory has documented a progressively developing hypoglycemia associated with systemic hypotension, hepatosplanchnic pathology, and death in endotoxin-shocked dogs . Recent data documented accelerated uptake of glucose in blood following endotoxin, with certain components of the buffy coat responsible for the increased uptake . The present study utilizing the awake dog assayed a possible protective role of leukocytes against the lethal effects of endotoxin . Animals were divided into paired groups: saline controls (Group I) and endotoxin experimentals (Group II) . Group II animals were injected intravenously with sublethal doses of E . coli endotoxin on 2 successive days (Days 1 and 2), LD100 on the third day, and 2 X LD100 on Day 4 . The control group received equal volumes of saline on Days 1, 2, and 3, but on Day 4 received a superlethal dose of endotoxin identical to the experimental group . The awake dog became febrile and exhibited initial leukopenia with subsequent marked leukocytosis in response to endotoxin . Lethal hypoglycemia was not seen in animals demonstrating initial leukocytosis (zero time) on the day of superlethal endotoxin challenge, while animals with initial normal leukocyte counts died with low glucose concentrations (mean, 40 mg%) . Results suggest that an initial leukocytosis and sustained gluconeogenic function are important factors in survivability to endotoxin shock.

Genetika, 1977, 13(8), 1441 - 5
{Site-specific recombination between phages lambda and phi 81 and integration of hybrid phages lambda-phi 81}; Balandina L et al.; Dependence of the formation frequency of hybrid phages immlambdahphi81 and immphi81hlambda in recombination between phages lambda and phi81 from int-function of both phages is studied . Phages with hybrid att-sites (Plambda OP'phi81 and Pphi81OP'lambda) are isolated and the efficiency of integration of these phages into bacterial chromosome is determined.

Genetika, 1977, 13(7), 1281 - 8
{Escherichia coli cell competence induced by calcium cations}; Sabel'nikov AG et al.; Escherichia coli K-12 cells grown to early and late exponential, and early and late stationary phases were treated with CA2+ and analysed for the ability of exogenous 14C-DNA uptake and genetic transformation . DNA-membrane complexes were detected detected by isopicnic centrifugation of cell lysates in sucrose density gradient . It is found that 1) during all the tested phases of the growth cycle, E . coli cells attain the ability of enhanced DNA uptake after Ca2+ treatment; 2) exogenous and host DNAs are associated with the cell membrane during all tested growth phases; 3) nevertheless, the ability to form transformants is strongly time-dependent: the cells can be transformed during logarithmic phase only; 4) Ca2+ protects exogenous DNA against its degradation by bovine pancreatic DNAase . The peculiarities of Ca2+-induced competence, actual and possible interference of Ca2+ at different transformation steps are briefly discussed.

Genetika, 1977, 13(7), 1252 - 9
{Genetic control of Escherichia coli K-12 strains' assimilation of 2,6-diaminopurine as a purine source}; Kocharian ShM; Mutations of the resistance to 2,6-diaminopurine (apt), which affect adenine phosphoribosyltransferase, fail to permit the growth of Escherichia coli pur mutants (purine auxotrophs which cannot make inosine monophosphate de novo) on the medium with 2,6-diaminopurine (DAP) as the sole source of purines . Addition of a small amount of hypoxantine, but not guanine, stimulated the growth of mutants of pur apt and pur apt+ genotypes on the medium with DAP . The utilization of DAP as purine source in the presence of hypoxantine is blocked by mutations guaC (guanosine monophosphate reductase), add (adenosine deaminase) and pup (purine necleoside phosphorylase), suggesting that DAP are utilized via purine nucleoside phosphorylase and adenosine deaminase . The drm mutation (that increases the level of pentose-1-phosphate in the cell) does not activate the utilization of DAP . The results indicate that a step, that limits the utilization of DAP as the sole source of purines by pur mutants of E . coli, is the deamination of DAP nucleoside.

Genetika, 1977, 13(7), 1246 - 51
{Single-stranded conjugation in Escherichia coli K-12: characteristics of the formation of a heterogenous progeny}; Goryshin IIu et al.; During a single-stranded conjugation donor DNA, being a single-stranded form, takes part in the process of recombination . That is why a heteroduplex DNA must be an intermediate product of the recombination . The heteroduplex can be partially corrected as it was supposed for genetic transformation . The division of such a corrected heteroduplex gives the heterogenous progeny of exoconjugants . And this "correctional" heterogeneity must possess two following properties: 1) the mixed progeny must consist of only two recombinational genotypes; 2) the heterogeneity must be marker-specific . The experimental support to both predictions was obtained by the method of clonal analysis of conjugational merozygotes.

Arzneimittelforschung, 1977, 27(8), 1521 - 32
{Studies on synergistic behaviour and pharmacokinetics of the combination sulfonamide/trimethoprim . IV . A comparative study on potentiating the trimethoprim effect by various sulfonamides and critical observations on its dosing (author's transl)}; Seydel JK et al.; The maximum possible inhibitory effect of sulfonamide-(SA)-trimethoprim (TMP) combinations on E . coli is obtained with rather small concentrations of SA according to the results obtained with bacterial growth kinetic studies . In these studies the TMP concentration (significantly below the minimum plasma level) was kept constant and the SA concentration varied . An "antagonistic" effect of high SA concentrations on the synergistic effect of the combination and a reduction of the inhibitory effect of TMP has been observed . According to the results of the bacterial growth kinetics obtained with E . coli and pharmacokinetic studies presented, the suggested dose for the combination 2-sulfa-4,5-dimethyl-oxazole/TMP seems to be sufficient, the dosage regimen is correct, whereas the amount of 3-sulfa-5-methyl-isoxazole (SMZ) in the dose proposed for the combination SMZ/TMP seems to be unreasonably high and the dosage scheme is incorrect.

Genetika, 1977, 13(6), 1126 - 8
{Induction of the synthesis of various colicins by the action of N-methyl-N'-nitro-N-nitrosoguanidine and chloramphenicol}; Khmel' IA; The effect of N-methyl-N'-nitro-N-nitrosoguanidine on colicinogenic cells is shown to result in the induction of the synthesis of colicins B1, B4, K, Ia-CA53, Ib-P9 and V3 . Chloramphenicol induces the synthesis of colicins B1, B4, K, V3 and, possibly, Ib-P9 . The data obtained indicate, that there is a similarity between derepression mechanisms of different colicinogenic factors.

Arch Exp Veterinarmed, 1977, 31(2), 299 - 316
{Quantitative analysis of the gastrointestinal flora in the piglet prior and after weaning with special reference to the pathogenesis of Coli-enterotoxemia}; Schultze F; The gastro-intestinal flora of clinically intact piglets on an industrialised sow unit was investigated prior to weaning (n = 12) and after weaning (n = 12) . The age of the former group was 23 to 36 days and that of the latter between six and eleven days . While enormous proliferation of haemolysing E . coli was recorded from the anterior portion of the small intestine in the post-weaning group, weaning, quite, generally, was found to have only little impact upon the gastrointestinal flora of piglet . More particularly were there no indicators to the effect that post-weaning proliferation of enteropathogenic strains was favoured by any correlation whatsover between E . coli and other bacterial species or between different types of E . coli . Other factors of possible importance to the pathogenesis of coli-enterotoxaemia are discussed with reference to literature.

Arch Exp Veterinarmed, 1977, 31(2), 191 - 202
{Experimental studies on the pathogenesis of Coli-enterotoxemia in swine . 4 . Effect of lipopolysaccharide endotoxin on weaned piglets following parenteral administration}; Johannsen U; Ten clinically intact weaned piglets were experimentally intoxicated by intravenous injection of lipoproteide-free lipopolysaccharide endotoxin according to Westphal of E . coli O 127:B8 . Severe endotoxin shock with all clinical manifestations of experimental coli-enterotoxaemia was induced in all animals and included circulatory disorder with tachycardia, intermittent pallor and/or cyanosis, symptoms of severe systemic intoxication, neurological symptoms, such as lack of coordination, hindleg staggering, spasm, paresis, paralysis, changes in respiration, such as rise in respiratory frequency and deepened breathing premortal deceleration of respiration and gasping for breath, temperature, variation, including hyperthermia and aggravating hypothermia, gastro-intestinal symptoms, such as temporary vomiting and persistent diarrhoea, leucopenia, eosinopenia, variation of haematocrit, edematisation, increased transudation, congestion, and gastro-intestinal shock lesions . Eight animals died . These experiments quite obviously have confirmed that endotoxin shock is the common pathogenetic principle behind all forms of coli-entertoxaemia (i.e, the forms of edematisation, cardiovascular failure, and gastro-intestinal processes.) Lipopolysaccharide endotoxin alone may be responsible for the development of both edemas and neurotoxic symptoms (edema disease) and diarrhoea (gastro-intestinal form of coli-enterotoxaemia) . The pathogenetic relevance of additional toxins (neurotoxin and enterotoxin) is discussed under this aspect.

Zentralbl Gynakol, 1977, 99(10), 596 - 9
{Lymphocyte transformation rate in "high risk newborn infants" in relation to the gestational and postnatal ages (author's transl)}; Wiersbitzky S et al.; In 74 "high risk newborn infants" of different gestational ages (at an age of 31 .... . 42 weeks) the ability of efficiency of the cellular immunity system was examined by means of the lymphocyte transformation test on different days of the first week of the postnatal life . Beside PHA also Streptolyson O and E . coli antigen were used . We ascertained a possible relationship between the pre- or postnatal age and the lymphocyte transformation rate by means of regressive analyses . We didn't find a linear relationship; the results are discussed.

Nucleic Acids Res, 1977, 4(5), 1681 - 94
Analogs of methionyl-tRNA synthetase substrates containing photolabile groups; Wetzel R et al.; Three photolabile analogs of substrates of methionyl-tRNA synthetase were synthesized . In one, the 4-thiouridine at the 8 position of E . coli tRNAfMet was alkylated with {14C}p-azidobromoacetanilide . In the second, {14C}p-azidobenzoic acid hydrazide was condensed with the 3'-terminal dialdehyde of periodate-oxidized Escherichia coli tRNAfMet . The modified tRNAs could be purified by chromatography on benzoylated DEAE-cellulose . The third photolabile compound was {3H}methioninyl-8-azido-adenosine 5'-phosphate, an analog of the methionyl adenylate intermediate in the aminoacylation reaction . Irradiation of each of these compounds in the presence of equimolar amounts of E . coli methionyl-tRNA synthetase of micrometer concentrations gave 5-15% crosslinking.

Nucleic Acids Res, 1977, 4(5), 1667 - 80
A strong ethidium binding site in the acceptor stem of most or all transfer RNAs; Wells BD et al.; E . coli unfractionated tRNA and tRNA phe both contain a single strong ethidium binding site . Singlet-singlet energy transfer has been used to measure the distance between this site and dansyl hydrazine covalently attached to the 3' end of the tRNAs . The distance obtained is between 33 and 40 A for both samples . This is completely consistent with results from earlier NMR studies which placed the single, strong ethidium binding site of yeast tRNAphe between base pairs 6 and 7 on the aminoacyl stem . From the known tertiary structure of tRNAphe it is possible to rationalize the unusual affinity of this site and its likely existence in all tRNAs.

Nucleic Acids Res, 1977, 4(5), 1569 - 78
Separation of the complementary strands of DNA fragments on polyacrylamide gels; Szalay AA et al.; 32P-labeled (in vivo) phiX174 RFI DNA was restricted by Hinc II . Three aliquots of the same digest: a) nondenatured, b) heat denatured, and c) denatured by 5 mM Me-HgOH were analyzed on 3-15% acrylamide gel gradients or on 3% gels with reduced N,N'-methylene-bis-acrylamide . The autoradiography of the gels showed that the nondenatured sample migrates two times faster than the denatured samples . After denaturation each original fragment appeared as a doublet . Using in vitro synthesized RFI DNA labeled only in negative strand with 32P we could identify the position of the negative strand in each denatured doublet . The single strand DNA fragments could be recovered from the gel slices on a semi-preparative scale by electrophoresis into dialysis tubing.

Nucleic Acids Res, 1977, 4(5), 1465 - 82
Physical properties and gel electrophoresis behavior of R12-derived plasmid DNAs; Mickel S et al.; A series of closed circular (I) plasmid DNAs has been derived from drug resistance factor R12, and the nicked circular (II) and linear (III) derivatives of these molecules prepared by irradiation in the presence of ethidium bromide and by treatment with restriction enzyme EcoRI, respectively . These DNAs encompass the molecular weight range 3.6 to 61 megadaltons . The base compositions range from 45% to 51% (GC) as estimated by buoyant density determinations . The smaller plasmids are significantly less supercoiled (9-10%) than are the larger (12-13%) . The gel electrophoretic behavior of the three DNA structural forms was determined as a function of molecular weight in agarose gels of concentrations ranging from 0.7% to 1.6% and at electrophoresis salt concentrations from 0.02 M to 0.08 M sodium acetate . The mobilities of DNAs I and III undergo a reversal relative to each other at a molecular weight which decreases with increasing agarose gel concentration . The molecular weight at which DNA II fails to enter a gel depends upon the ionic strength during electrophoresis but not upon the gel concentration.

Nucleic Acids Res, 1977, 4(5), 1315 - 38
Microheterogeneity detected in circular dimer mitochondrial DNA; Robberson DL et al.; Exhaustive EcoRI digests of circular dimer mitochondrial DNA (mtDNA) from mouse cell lines LD and LDTK- yield two major fragments whose average lengths are slightly smaller than the corresponding fragments of circular monomer mtDNA from mouse LA9 and LMTK- cells . A third fragment approximately 400 nucleotide pairs in length is frequently produced in less than molar yield . Exhaustive EcoRI digests of circular dimer mtDNA from human acute myelogenous leukemic leucocytes yield three major fragments . The presence of mtDNA resistant to cleavage as well as fragments of intermediate sizes indicatesmicroheterogeneity in the genomic positions of EcoRI recognition sequences in both mouse and human circular dimer mtDNA . Analysis of the distribution averages of circular contour lengths indicates microheterogeneity in the sizes of mouse LD and human mtDNAs . The denatured-renatured EcoRI fragments frequently contain a small loop(s) of single-strand DNA as would occur for deletion(s) or addition(s) of single-strand DNA as would occur for deletion(s) or addition(s) of nucleotide sequences in some of the circular dimer molecules.

Nucleic Acids Res, 1977, 4(5), 1291 - 9
Restriction endonuclease cleavage maps of rat and mouse mitochondrial DNAs; Parker RC et al.; Mitochondrial DNA from an Old World mouse, Mus musculus, and from an Old World rat, Rattus norvegicus, contain 19 and 22 distinct sites, respectively, for the 8 restriction endonucleases, BamHI, EcoRI, HaeII, HhaI, HincII, HindIII, HpaI and PstI . The relative positions of the sites have been mapped by the study of partial and double enzyme digests . Some sites may been conserverd between the mouse and rat mitochondrial genomes.

Nucleic Acids Res, 1977, 4(5), 1273 - 89
A restriction endonuclease cleavage map of mouse mitochondrial DNA; Moore KH et al.; A restriction endonuclease cleavage map is presented for mouse mitochondrial DNA . This map was constructed by electron microscopic measurements on partial digests containing fixed D-loops, and by electrophoretic analysis of partial and complete single enzyme digests, and of double digests . No map differences were detected between mitochondrial DNA from cultured LA9 cells and an inbred mouse line for the six endonucleases used . Three cleavage sites recognized by HpaI, five sites recognized by HincII, two sites recognized PstI and four sites recognized by BamI were located with respect to the origin of replication and the EcoRI and HinIII sites previously determined by others . No cleavages were produced by KpnI or SalI . The migration of linear DNA with a molecular weight greater than 1 X 10(6) was not a linear function of log molecular weight in 1% agarose gels run at 6.6 volts/cm.

Nucleic Acids Res, 1977, 4(5), 1225 - 41
Physiochemical studies on interactions between DNA and RNA polymerase . Unwinding of the DNA helix by Escherichia coli RNA polymerase; Wang JC et al.; In a medium containing 10mM Tris, pH 8, 10 mM MG++, 50 mM K+ and 10 mM NH4, the binding of an E . coli RNA polymerase holoenzyme unwinds the DNA helix by about 240 degrees at 37 degrees C . In this medium the total unwinding of the DNA increases linearly with the molar ratio of polymerase to DNA . The number of binding sites at which unwinding can occur is very large . If the K+ concentration is increased at 200 mM, the enzyme binds to only a limited number of sites, and the bound and free enzyme molecules do not exchange at an appreciable rate . The unwinding angle of the DNA per bound enzyme in this high salt medium is measured to be 140 degrees at 37 degrees C . The total unwinding angle for a fixed number of bound polymerase molecules per DNA is strongly temperature dependent, and decreases with decreasing temperature.

Nucleic Acids Res, 1977, 4(5), 1207 - 23
Studies of ColE1-plasmid DNA and its interactions with histones: sedimentation velocity studies of monodisperse complexes reconstituted with calf-thymus histones; Voordouw G et al.; Complexes between the four calf-thymus histones (H2A, H2B, H3 and H4) and colE1-plasmid DNA have been reconstituted using the procedure of Oudet et al . ((1975), Cell 4, 281-300) . The sedimentation rates of the complexes formed were studied under a variety of conditions . In 0.4 MNaCL, 0.1 M Tris pH 7.50, 0.01 M EDTA and 0.02 M NaHSO3, the final dialy-sis-solvent in the reconstitution procedure, the sedimentation coefficients s23 were found to increase when the complexes were reconstituted at increasing histone to DNA ratios . True plateau regions were reached in the case of the relaxed circular and linear forms of the plasmid DNA . The sedimenting boundaries observed for the complexes at saturation are sharp, reflecting a narrow distribution of sedimentation coefficients and a homogeneity of the complex comparable to that of the uncomplexed DNA . Studies of the dependence of s 23 on the concentration of the complex at constant DNA to histones ratio have been undertaken at salt concentrations between 0.4 and 1.5 M NaCL in the above solvent . The formation of the complexes is reversible, at least at the higher ionic strengths . At salt concentrations below 0.36 M the complex precipitates from solution . Omission of histone H4 from the reconstitution mixture abolishes complex formation.

Nucleic Acids Res, 1977, 4(5), 1159 - 81
Supercoiling energy and nucleosome formation: the role of the arginine-rich histone kernel; Camerini-Otero RD et al.; We have formed complexes of relaxed closed circular Col E1 DNA with various combinations of histones, and examined the effects of treating the complexes with nicking-closing enzyme . Germond et al (1) have shown that when a mixture of the four core histones of the nucleosome (HIA, H2B, H3 and H4) is used in such an experiment, the subsequently isolated DNA is supercoiled . We find that the arginine-rich histone pair, H3 and H4, is sufficient to induce the supercoiling observed in this experiment . Both H3 and H4 are required, and in the absence of either, no other histones are effective . H3 and and H4 are as efficient, per unit weight, as a mixture of the four histones in inducing supercoils . We also show that there is a large difference between the DNA bending energy needed to form a nucleosome and that needed to form one turn of normal superhelical DNA . These two processes are energetically quite distinct and probably separable . We estimate the free energy of interaction between DNA-bound histone pairs, and find that one or two such interactions would generate enough energy to fold the DNA into a nucleosome.

Folia Microbiol (Praha), 1977, 22(4), 241 - 7
Simultaneous and successive induction of synthesis of beta-galactosidase and tryptophanase in Escherichia coli K 12 in the chemostat; Pavlasova E et al.; beta-Galactosidase and tryptophanase were induced either simultaneously or successively during continuous cultivation of the inducible strain Escherichia coli K 12 in the chemostat . Growth was limited by glycerol and the dilution rate was 0.1 h-1 . During both the simultaneous and successive induction specific rates of synthesis, as well as maximum enzyme levels, were identical with those obtained after independent induction of individual enzymes . As compared with batch cultivation, beta-galactosidase reached the same specific rate of synthesis in the chemostat, whereas the specific rate of synthesis of tryptophanase in the chemostat was up to five times higher.

Genetika, 1977, 13(4), 681 - 8
{Effect of amino acid substitutions in the polypeptide chain of DNA-polymerase on manifestation of the mutator effect}; Piruzian ES et al.; Thin map of gene 43, controlling the synthesis of T4 DNA polymerase, is obtained by mapping experiments performed with 39 amber mutants, and is used for analysis of the sites of DNA polymerase gene from the point of view of displaying the mutator effect . The mutant sites studied possessed different reaction on amino acid substitutions in the polypeptide chain of the enzyme . Most of sites of the DNA polymerase gene, with the exception of two "supersensitive", responsed only on the apparent type of the amino acid substitutions: the mutator effect of amber mutations, which are located at these sites, was exhibited only in the case of insertion of the definite amino acid in the respective point of polypeptide chain . The proposed system of amber mutations for studying the mutator effect, allowed the authors to obtain the data on the effect of concrete alterations in the polypeptide chain of the enzyme on the development of its mutator properties.

Genetika, 1977, 13(2), 272 - 85
{Identification of 3 genes in the F-plasmid of Escherichia coli K-12}; Chernin LS et al.; The F'argG plasmid and its two transfer-deficient (tra-) analogues have been used to analyse the pleiotropic effect of a mutation in the integrated F-factor of HfrC strain . This mutation has been shown to disturb the functioning of at least three plasmid genes constituting, probably, a single regulon: the rsf gene determining the production of recombination-stimulating factor via conjugation (RSF); the prt gene responsible for the protective effect of the plasmid against N-methyl-N'-nitro-N-nitrosoguanidine, methyl methanesulphonate and UV-irradiation; the rep gene the product of which can be involved in the control of Hfr-chromosome replication . Possible location and order of the genes in the F-plasmid are discussed.

Eksp Med Morfol, 1977, 16(2), 76 - 9
{Study of gastric secretion in white rats with a chronic gastric fistula on endotoxin exposure}; Nikolov N et al.; The author carried out a study on the stomach secretion in white rats endotoxin shock, induced by venous adminsitration of endotoxin, obtained from Escherichia coli . Stomach fistula was made on the rats in advance and the stomach juice was collected under the condition of chronic experiment . The amount of stomach juice was estimated in mililiter per hour as well as the content of free hydrochloric acid, total aidity and electrophoresis of proteolytic enzymes . There was a statistically significnat lowering of the amount of stomach juice, diminuation of free hydrochloric acid and of total acidity acidity as well as diminution of complete disappearence of its proteolytic activity in the rats after endotoxin action.

Folia Microbiol (Praha), 1977, 22(3), 232 - 6
Replication of DNA in UV-irradiated Escherichia coli in the absence of amino acids; Sedliakova M et al.; Since pyrimidine dimers are considered to be the cause of the synthesis of short DNA segments, normalization of DNA replication after UV irradiation should be in a temporal correlation with their removal . This correlation holds in exponentially growing excision-proficient Escherichia coli cells . However, when these cells are preincubated and postincubated without amino acids, synthesis of short segments continues although dimers are efficiently excised.

Folia Microbiol (Praha), 1977, 22(3), 173 - 81
Inhibition of beta-galactosidase synthesis in Escherichia coli after infection with different DNA and RNA phages; Jiresova M et al.; Infection of Escherichia cooi with T1, T2r+, T3 and T4 phages leads to an immediate inhibition of beta-galactosidase synthesis . Similar results were obtained with the virulent mutant of phage lambda . The degree of inhibition of beta-galactosidase synthesis depends on the time delay between the addition of the inducer and the phage particles, and on the amount of phage DNA, which has penetrated into the host cell . RNA phage MS2 exhibited no inhibitory effect on enzyme synthesis.

Biochimie, 1977, 59(4), 403 - 9
Oxidative phosphorylation in intact chl-r mutants of Escherichia coli K 12; Giordano G et al.; The efficiency of oxidative phosphorylation was estimated in intact resting cells of Escherichia coli K 12, strain PA 601 (chl-s) and its chl-r mutants, all of them grown anaerobically in the presence of nitrate . The oxidation of endogenous NADH in intact chl-s cells was accompanied by the formation of ATP whatever the terminal electron acceptor, oxygen or nitrate, so that it was possible to conclude that the energy conservation sites are operating with either of the two acceptors in cells grown anaerobically in the presence of nitrate . For chl-r mutants oxidation of endogenous NADH correlated with ATP-production was found only with oxygen as electron acceptor . It is concluded that the energy-conservation sites are preserved in these mutants, the nitrate respiratory chain of which is altered . This assumption is corroborated by the effects of uncouplers of oxidative phosphorylation on ATP-synthesis.

Acta Biochim Pol, 1977, 24(2), 143 - 51
Transcription of rat DNA fractions reassociated to various cOt values; Grabowska M et al.; Two fractions of rat liver DNA: "intermediate" (reassociated to COt = 1 - 10(2), moleXsecX1(-1)) and "slow" (COt = 10(2) - 10(5) showed differences in template activity on transcription with E . coli RNA-polymerase . The "intermediate" fraction both in double- and single-stranded form was a better template than the "slow" one . The efficiency of transcription dropped progressively for the template obtained at COt values increasing from 10(2) to 10(6) . No differences in the template activity of the "intermediate" and "slow" fractions were observed when rifampicin-resistant transcription was studied.

Z Allg Mikrobiol, 1977, 17(3), 235 - 42
Anaerobic growth of Escherichia coli on formate by reduction of nitrate, fumarate, and trimethylamine N-oxide; Yamamoto I et al.; Anaerobic growth of E . coli, strain K-10, depending on formate oxidation by nitrate, fumarate, and trimethylamine N-oxide was followed in a medium containing peptone . The presence of formate and peptone was indispensable for growth with fumarate and trimethylamine N-oxide reduction . While there was no growth in the absence of acceptor, growth was observed in the absence of formate by nitrate reduction though not as much as under aerobic conditions . Per mole consumed formate equimolar succinate or trimethylamine was formed, but 1.2 mole of nitrate was produced, probably depending partly on peptone oxidation . The molar growth yield on formate was found to be 6.5, 7.6, and 7.0 g cells/mole depending on the reduction of nitrate, fumarate, and trimethylamine N-oxide, respectively, suggesting the formation of one mole ATP coupled to the anaerobic electron transfers from formate.

Z Allg Mikrobiol, 1977, 17(2), 131 - 7
{Transient behavior of the ammonium-limited chemostatic cultures of Escherichia coli ML 30}; Muller PJ et al.; In connection with the bistability of pyruvate formation in ammonium limited continuous cultures of E . coli ML 30 (Bergter u . Roth 1977) the transient behaviour of cell density and pyruvate concentration were studied . Immediately after a shift up in the dilution rate from D = 0.15 h-1 to D = 0.6 h-1 the bacteria excreted pyruvate into the medium, followed by a resumption of pyruvate . The specific pyruvate formation rate as well as the specific growth rate reached the new steady state with damped oscillations . Possibly the excretion of pyruvate after the shift is caused by the higher non limiting concentrations of ammonium during the first of the transition . This hypothesis is supported by the transient behaviour of an ammonium limited continuous culture after a pulse of ammonium to the culture . The relations between ammonium metabolism and pyruvate formation are discussed.

World J Surg, 1977 Jan, 1(1), 85 - 90
The effect of stored blood on mesenteric oxygen extraction during exdotoxin shock; Garg DK et al.; Storage of blood in acid-citrate-dextrose (ACD) solution gradually depletes red cell 2,3-diphosphoglycerate (DPG) and increases the affinity of hemoglobin for oxygen . We examined the effect of exchange transfusion of DPG-depleted blood on mesenteric blood flow and oxygen consumption in dogs subjected to endotoxin shock . Two groups of 6 dogs each were anesthetized and subjected to exchange transfusion with either fresh ACD blood or 21-day-old ACD blood prior to administration of Escherichia coli endotoxin (2 mg/kg) . Mesenteric blood flow, arteriovenous oxygen content difference and systemic arterial blood pressure were monitored continuously before and for 60 min after endotoxin . Mesenteric blood flow was reduced from 250 +/- 21 ml/min before endotoxin to 114 +/- 15 ml/min at 5 min, 157 +/- 29 ml/min at 30 min, and 112 +/- 17 ml/min at 60 min after endotoxin in the dogs exchanged with fresh blood . Corresponding values for intestinal oxygen consumption were 10.4 +/- 1.0, 7.5 +/- 0.8, 8.4 +/- 1.0, and 6.8 +/- 0.7 ml/min . In dogs transfused with 21-day-old blood, pre-endotoxin blood flow was 208 +/- 2ml/min and declined to 115 +/- 12, 93 +/- 5, and 80 +/- 8 ml/min at 5, 30, and 60 min post-endotoxin . Corresponding values for intestinal oxygen consumption were 8.1 +/- 0.9, 6.6 +/- 0.7, 6.2 +/-0.5, and 5.5 +/- 0.7 ml/min . There was no significant difference (p greater than 0.1) in responses of blood flow or oxygen consumption to endotoxin shock between the two groups of dogs . These findings indicate that exchange transfusion with DPG-depleted blood does not impair oxygen extraction by the ischemic intestine.

Nucleic Acids Res, 1977 Jan, 4(1), 17 - 29
Requirement of chain initiation factor 3 and ribosomal protein S1 in translation of synthetic and natural messenger RNA; Sobura JE et al.; Amino acid incorporation directed by poly(A), poly(U) or R17 RNA has been examined in S1-depleted protein synthesizing systems . We observe that the translation of either synthetic or natural messenger RNA is strictly dependent on the presence of chain initiation factor 3 and ribosomal protein S1 . With poly(A) or poly(U) both IF-3 and S1 stimulate amino acid incorporation at least 25-fold, and with R17 RNA the stimulation is approximately 15-fold . More than one copy of S1 per ribosome decreases amino acid incorporation directed by poly(U) or R17 RNA . Initiation complex formation with R17 RNA is also stimulated optimally by the addition of one copy of S1 per ribosome . The function of IF-3 and S1 in protein synthesis is considered.

Biochimie, 1977, 59(2), 163 - 70
{Gratuitous induction of beta-glucuronidase of Escherichia coli K 12 and the double repression mechanism}; Mandrand-Berthelot MA et al.; Using natural inducers of beta-glucuronidase, methyl-glucuronide and fructuronate, under gratuitous conditions (without metabolic conversion of these two compounds), we corroborate the fact that both molecules are required simultaneously in order to derepress the enzyme synthesis to a maximum level . Structurally related analogs of the natural inducers, thiophenyl-glucuronide and mannonic amide respectively, were assayed in the wild type and suitable mutant strains of E . coli . The results are in agreement with the model where the dual negative regulation of the enzyme synthesis is exerted by two regulatory genes uidR and uxuR . The concerted action of mannonic amide and thiophenyl-glucuronide, which alone fail to induce significantly beta-glucuronidase synthesis, reveals that a cooperative effect of the two repressor molecules responsible for the complete blocking of the enzyme synthesis is occuring.

Arch Exp Veterinarmed, 1977, 31(1), 15 - 27
{Coagulation analytical studies in coli enterotoxemia in swine}; Schimmel D et al.; Store pigs with spontaneous outbreaks and experimental endotoxin shock were kept under observation in the context of coagulation analysis . Heparin was applied to some of the animals to disrupt the plasmatic coagulation system . The thrombocyte count in animals with endotoxin infusion declined by some 50 to 65 percent of the original level . No statistically secured difference was found to exist between heparinised animals, on the one hand, and non-heparinised, on the other . The aggregation and adhesion of thrombocytes in all shock animals was more pronounced than that in the controls . The fibrinogen levels were lowered in both the animals with spontaneous outbreaks and the experimental animals . Thrombocyte alteration was not found to have been dependent on activation of the plasmatic coagulation system . In endotoxin shock cases activation of plasmatic coagulation proteins was found to be preceded by rise in thrombocyte aggregation.

Arch Invest Med (Mex), 1977, 8(1), 71 - 83
{Ultramicroscopic study of the colonic mucosa infected by E . histolytica}; Trevino N et al.; In eight guinea pigs, trophozoites of E . histolytica HM-2 IMSS strain grown in plurixenic conditions were inoculated in their cecum . Two died two days after inoculation; the remaining si- were sacrificed six days afterwards . Tissue samples were obtained from amebic lesions and nearby areas . At ultramicroscopic level it was observed that epithelial cells in contact with the parasite had short and/or scanty microvilli, swollen mitochondria, ER dilatation and absence of the terminal bar . When trophozoite was within the epithelium, cells in contact with it were destroyed; basement membrane was elongated before it was broken up by the parasite . In the lamina propria trophozoites were found close to glands, blood capillaries and in contact with macrophages, lymphocytes, and most cells . No polymorphonuclear cells were identified in all samples studied . Capillaries were congestive, lacking polymorphonuclear cells . It was postulated that probably initial colonic mucosa lesion in amebiasis depends solely upon parasite action.

Arch Int Pharmacodyn Ther, 1977 Jan, 225(1), 39 - 50
Effects of antipyretic agents on fever and ruminal stasis induced by endotoxins in conscious goats; van Miert AS et al.; Intravenous injection of endotoxin (LPS) from S . typhimurium (3,3 microng per kg body weight) or E . coli O111B4 (0,1 microng per kg body weight) caused fever and stasis of the forestomach contractions in conscious goats . Pretreatment with non-steroidal anti-inflammatory agents only had a partial antagonistic influence upon endotoxin induced ruminal stasis . In this respect, acetaminophen was the most potent drug of all agents tested . In dependence of the doses used, the following rank order of potency can be given in relation to the antipyretic activity: sodium flurbiprofen, sodium meclofenamate, acetaminophen, sodium novaminsulphonum and phenylbutazone . In the goat, sodium flurbiprofen (2 mg per kg i.v.) is a very potent and long acting antipyretic agent . It seems unlikely that the inhibition of forestomach motility by endotoxins is simple due to a release of prostaglandins . Since the inhibition also occurred in absence of a febrile response, it is concluded that the inhibition is not primarily due to hyperthermia.

Ann Immunol (Paris), 1977 Jan-Mar, 128(1-2), 173 - 5
{Asynchronism in the synthesis of antibodies directed against different antigenic sites of a macromolecule}; Conway de Macario E et al.; "Activating" and "precipitating" antibodies elicited by Escherichia coli beta-D-galactosidase can be isolated by assortment of the respective antibody-forming cells in vitro, showing that the two antibodies have different specificities . Both populations also segregate in vivo and are synthesized asynchronously . The interplay of different antibody species with the same immunogenic molecule and the role of these expected to be complex interactions in the regulation of the immune response is an area for further investigation.

Scand J Thorac Cardiovasc Surg, 1977, 11(1), 43 - 50
Synthetic arterial grafts . II . infection complications; Christenson J et al.; A retrospective study of 91 patients with synthetic arterial grafts was made . The investigation showed that infection of synthetic arterial grafts is a serious and life-threatening complication . Of our 14 infected cases, 5 patients were amputated and 4 patients died . The incidence of infection is significantly increased when the anastomosis is performed through a groin incision . In addition the management of patients with infected graft is discussed and two cases are reported.

Prep Biochem, 1977, 7(1), 9 - 18
Complementable fraction and complemented enzyme of mutant M15 from Escherichia coli: partial purification by affinity chromatography; Marinkovic DV et al.; The technique of affinity chromatography has been used in the partial purification of complementable fractions and complemented enzyme of beta-galactosidase from Escherichia coli mutant M15 . The crude extract of mutant M15 was incubated with fragment CM-B . The complemented enzyme and complementable fractions were passed through a small column of p-aminophenyl-beta-D-thiogalactoside to which inhibitors had been covalently attached . A high percentage of the nonspecific protein passed directly through the affinity column while the specific enzymatic protein remained bound to the gel . Phosphate buffer with NaCl was used to elute the complementable fractions from the column . Sodium borate buffer was used to elute the bound complemented enzyme from the affinity support . The results of this study show that 100% of the complemented enzyme was bound to the column . The partially purified enzyme had the same position in disc gel electrophoresis as beta-galactosidase from E . coli.

Folia Microbiol (Praha), 1977, 22(2), 81 - 91
Repair, replication and survival in uv-irradiated Escherichia coli; Sedliakova M et al.; The influence of dimer removal through excision or photoreactivation on the kinetics of DNA synthesis, sedimentation profiles of DNA molecules and survival of cells was investigated in excision-deficient and excision-proficient Escherichia coli K-12 after a flux of 20 J M-2 . In excision-deficient cells photoreactivation did not influence the kinetics of DNA synthesis for a long period and the sedimentation properties of DNA synthesized immediately after photoreactivation were influenced only slightly . However, survival was increased remarkably . In excision-proficient cells where dimers were removed through excision, the kinetics of DNA synthesis increased rapidly, normal-sized DNA molecules were synthesized 60 min after irradiation and survival was substantially higher than in the above-mentioned case . This can hardly be interpreted as a more complete repair of dimers by excision because the persistence of dimers in these cells did not significantly influence either the kinetics of DNA synthesis or normalization of DNA molecules and/or survival of cells . It is concluded that persisting dimers play an important role in excision-deficient but not in excision-proficient cells, that a non-dimer damage to DNA causes inhibition of DNA synthesis after UV and that this damage is of primary importance for excision-proficient cells which can easily cope with persisting dimers.

Folia Microbiol (Praha), 1977, 22(2), 106 - 16
Stimulation of L-asparaginase production in Escherichia coli by organic and amino acids; Netrval J; The effect of 18 amino acids and 7 organic acids on the production of L-asparaginase EC-2 by a strain of Escherichia coli in a chemically defined medium was investigated under moderate aeration . All the amino acids and some of the organic acids stimulated the enzyme production . The specific activity without stimulants was about 0.16 nkat per mg dry weight, with stimulants it lay between 1 and 6 nkat per mg dry weight but with L-leucine and L-methionine the values were 12 nkat and 17 nkat per mg, respectively . When two organic or amino acids were added simultaneously at concentrations that were suboptimal for stimulation, the stimulating effects were cumulative in most cases . When cells were grown under conditions approaching anaerobiosis, the specific activity reached, even in the absence of stimulants, values as high as 5 nkat per mg; under these conditions, a further substantial increase in specific activity was only caused by L-leucine and L-methionine . Stimulating effects of DL-lactate and of some amino acids were also found in other strains of Escherichia coli . The ability to grow on a medium with L-asparagine as the sole source of both nitrogen and carbon was found in two strains; growth took place even when there was no measurable activity of L-asparaginase EC-2.

Farmaco {Sci}, 1977 Jan, 32(1), 67 - 75
Investigations on the mechanism of action of narciclasine; Dall'acqua F et al.; The Authors have investigated the possible interaction between narciclasine and DNA using various physico-chemical techniques useful for demonstrating the complex formation between a small molecule and a marcomolecule . The data obtained clearly indicate that a complex between DNA and narciclasine does not occur . The mechanism of the antimitotic activity of narciclasine must therefore be of a different nature, such as interference with the enzymatic systems involved in the duplication of DNA or with the protein structures involved in nuclear division.

Pharmazie, 1977 Jan, 32(1), 22 - 4
Synthesis and pharmacological screening of certain spiro compounds; El-Telbany FA et al.; The synthesis of certain azaspirodione, azaspirane and bis-azaspirodione derivatives is described . Fusing equimolecular amounts of 3-oxaspiro{5.5}undecane-2.4-dione with certain amino compounds afforded the corresponding N-substituted azaspirodiones . Reduction of the N-harolaryl azaspirodiones gave the oxygen-free analogues . Reacting 3-azaspiro{5.5}undecane-2.4-dione with certain secondary amines under the Mannich conditions yielded the expected bases . Reacting one equivalent of ethylene-diamine with two equivalents of 2-oxaspiro{4.4}nonane-1.3-dione and the next higher homologues, viz, the decane and undecane afforded the respective ethylene bis-azaspirodiones . Likewise, on applying the Mannich conditions to the nitrogen analogues of the before-mentioned oxaspirodiones using piperazine as the secondary amine, bis-azaspirodions were obtained . The result of the pharmacological screening of some of the synthesized spiro compounds is included.

Folia Microbiol (Praha), 1977, 22(1), 66 - 73
Correlation between survival, ability to rejoin DNA and stability of DNA after preirradiation inhibition of protein synthesis in a rec mutant of Escherichia coli K12; Pirsel M et al.; A 90 min inhibition of protein synthesis induced by starvation for amino acids (AA-) or by treatment with chloramphenicol (CAP) prior to UV irradiation (2.5 Jm-2) increased the resistance of the strain Escherichia coli K12 SR19 to UV radiation more than ten-fold . Under these conditions, cultures in which protein synthesis was inhibited before the UV irradiation rejoin short regions of DNA synthesized after the irradiation to a normal-size molecule, whereas an exponentially growing culture does not rejoin DNA synthesized after UV irradiation to a molecule of a normal size . In the exponentially growing culture both the parental and the newly synthesized DNA are unstable after the irradiation . In cultures with inhibited protein synthesis only the parental DNA is somewhat unstable . In Escherichia coli K12 SR19 where protein synthesis was inhibited before the irradiation, a correlation between the survival of cells, the ability to rejoin short regions of DNA synthesized after UV irradiation and a higher stability of both parental and newly synthesized DNAs could be demonstrated.

Gut, 1977 Jan, 18(1), 28 - 32
Correlation between hepatic morphology and immunoglobulins and antibodies to Escherichia coli in cirrhosis; Prytz H et al.; Increased antibody production and hypergammaglobulinaemia in cirrhosis are probably to a large extent due to decreased hepatic extraction of antigens . The deceased extraction is presumably related to changed microcirculation caused by damaged anatomical structure of the liver . It is therefore to be expected that immunoglobulin and antibody levels in serum in cirrhotic patients are related to the degree of certain morphological changes of the liver . This hypothesis has been tested . In 50 patients with cirrhosis, 28 alcoholics and 22 non-alcoholics, the degree of architectural destruction, the degree of fibrosis, the degree of fatty infiltration, and the degree of "activity" were compared with immunoglobulins G, A, and M and E . coli O antibody levels . The comparison was carried out within each of the aetiological groups . Identical relationships were found in both groups . Patients with completely destroyed lobular architecture had higher levels of E . coli O antibodies than patients with partly destroyed architecture . Patients with severe fibrosis had higher IgA and E . coli O antibody levels than patients with moderate or slight fibrosis . Patients with moderate and severe steatosis and patients with no or slight steatosis had the same immunoglobulin and E . coli O antibody levels . Patients with active cirrhosis had higher IgG levels than patients with inactive cirrhosis . When architectural destruction and fibrosis were combined significantly higher IgG, IgA, IgM, and E . coli antibodies were found in the group with the most severe changes . These findings support the hypothesis that immunoglobulin and antibody levels are related to the degree of morphological changes in the liver--namely, destruction of lobular architecture, fibrosis, and "activity".

Chem Biol Interact, 1977 Jan, 16(1), 39 - 55
The interaction of an anti-tumour platinum complex with DNA; Roos IA; The interaction of the anti-tumour active cis platinum (II) complexes with DNA has been investigated using dichloro(ethylenediamine)platinum(II) and E . coli DNA . Equilibrium dialysis studies indicate that Pt(en)Cl2 binds reversibly to DNA to a saturation value of 0.57 Pt: P, which is consistent with the platinum being bound both monofunctionally and bifunctionally . Pt(en)Cl2 inhibits the intercalation of 9-aminoacridine (9AA) by cross-linking the bases of the double helix, but at no stage does all the bound platinum cross-link . It is suggested that this inhibition of intercalation is due to intrastrand cross-linking.

Ann Intern Med, 1977 Jan, 86(1), 35 - 9
Granulocyte adherence changes induced by hemodialysis, endotoxin, epinephrine, and glucocorticoids; Mac Gregor RR; Granulocyte adherence was studied in several situations of altered granulycyte kinetics . During the transient granulocytopenia of hemodialysis, adherence increased to 481.7% of baseline by 15 min and was normal by 60 min . One hour after endotoxin administration, adherence was 160.5% of control as granulocyte counts fell to 21.4%; conversely, the 24-h postdose granulocytosis was associated with a 43.0% decrease in adherence . Epinephrine produced a 25.8% decrease in adhereence, with demargination granulocytosis 146.1% of control period . Alternate-day prednisone administration inhibited adhereence by 38.9% on the "on" day, concomitant with prolonged granulocyte intravascular half-life, but adherence returned to normal on the "off" day when intravascular half-life is normal . In each situation, a plasma factor not present in serum was responsible for the modified adherence; if these factors produce the sameadherence changes in vivo, they may be responsible for the alterations noted in granulocyte kinetics.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 300 - 4
A mutant of Escherichia coli showing constitutive expression of the lysogenic induction and error-prone DNA repair pathways; Mount DW; A mutant of E . coli (designated the STS mutant) has been isolated in which the phage induction and error-prone DNA repair pathways appear to be expressed constitutively without the cells having received an inducing signal . Phage lambda was not able to lysogenize this mutant, whereas a noninducible mutant of lambda, lambdacIind-, known to synthesize a repressor that is insensitive to the induction mechanism, lysogenized it normally . This result suggested that normal phage repressor was synthesized in the STS mutant but was then inactivated by the induction mechanism . The STS strain also had mutator characteristics, and showed spontaneous, error-prone repair of UV-damaged phage lambda . Derived from a lexA tif sfiA parent strain, the STS mutant carried an additional mutation spr at the lexA locus that resulted in a high level of expression of the induction pathways . The properties of this and related strains provide additional evidence that induction of phage and induction of error-prone DNA repair occur by a similar mechanism, and further suggest a model for the regulation of these pathways.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 198 - 202
Proofreading of the codon-anticodon interaction on ribosomes; Thompson RC et al.; The fidelity of protein synthesis is substantially greater than the specificity of codon-anticodon recognition that would be expected from the known energetics of base-pairing in solution . To test the suggestion that the specificity of recognition may be increased by "kinetic proofreading" associated with GTP hydrolysis {J . J . Hopfield (1974) Proc . Natl . Acad . Sci . USA 71, 4135-4139}, we have studied the interaction of ternary complexes of polypeptide elongation factor Tu, aminoacyl-tRNA, and GTP with poly(U)-programed ribosomes . With most noncognate ternary complexes, including two that pair correctly with the 5' and 3' bases of UUU, rejection occurred without GTP hydrolysis, presumably by the reverse of the initial binding reaction . However, with complexes containing Leu- or Ile-tRNAs, which may pair correctly with the 3' and middle bases, GTP hydrolysis was stimulated though the aa-tRNA was not retained on the ribosome . These results demonstrate the existence of a GTP-dependent proofreading step in aminoacyl-tRNA recognition on ribosomes . They also suggest that the 5' base of the codon is more prone than the middle base to errors that can be corrected by proofreading.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 183 - 7
Sensory transduction in Escherichia coli: a requirement for methionine in sensory adaptation; Springer MS et al.; Chemotaxis of E . coli is a behavioral response to a change in the concentration of a stimulatory compound . The response is transient; thus, E . coli undergoes sensory adaptation . In this communication, we show that L-methionine is required by E . coli for adaptation to increases in the concentration of chemical attractants, but is not required for the maintenance of the adapted state . When the concentration of the attractant is lowered to its initial level, cells regain their sensitivity to the attractant . This process of deadaptation does not require methionine . We suggest that the methylation of a membrane protein, a reaction previously shown to be involved in chemotaxis {Kort, E.N., Goy, M.F., Larsen, S.H . & Adler J . (1975) Proc . Natl . Acad . Sci . USA 72, 3939-3943} underlies these phenomena.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 154 - 7
Transient accumulation of Okazaki fragments as a result of uracil incorporation into nascent DNA; Tye BK et al.; Strains of Escherichia coli with a mutation in the sof (dnaS) locus show a higher than normal frequency of recombination (are hyper rec) and incorporate label into short (4-5S) DNA fragments following brief {3H}thymidine pulses {Konrad and Lehman, Proc . Natl . Acad . Sci . USA 72, 2150 (1975)} . These mutant strains have now been found to be defective in deoxyuridinetriphosphate diphosphohydrolase (dUTPase; deoxyuridinetriphosphatase, EC 3.6.1.23), the enzyme that catalyzes the hydrolysis of dUTP to dUMP and PPi . Reversion of one sof- mutation to sof+ restores dUTPase activity and abolishes the accumulation of labeled 4-5S DNA fragments . Mutants initially isolated as defective in dUTPase (dut-) are also hyper rec and show transient accumulation of short DNA fragments . Both the sof and dut mutations are located at 81 min on the E . coli map, closely linked to the pyrE locus . The sof and dut loci thus appear to be identical . A decrease in dUTPase as a consequence of a sof or dut mutation may result in the increased incorporation of uracil into DNA . Rapid removal of the uracil by an excision-repair process could then lead to the transient accumulation of short DNA fragments . It is possible that at least a portion of the Okazaki fragments seen in wild-type cells may originate in this way.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 111 - 4
Interaction of tetraiodofluorescein with a modified form of aspartate transcarbamylase; Kantrowitz ER et al.; Low concentrations of the dye tetraiodofluorescein activate native aspartate transcarbamylase (aspartate carbomoyltransferase, carbomoylphosphate:L-aspartate carbomoyltransferase, EC 2.1.3.2), while high concentrations inhibit the enzyme's activity {Jacobsberg, L . B., Kantrowitz, E . R . & Lipscomb, W . N . (1975) J . Biol . Chem . 250, 9238-9249} . This dye is now shown to produce similar effects upon a modified form of aspartate transcarbamylase produced by Escherichia coli grown in a culture medium supplemented with thiouracil . Significantly, the ATP-induced activation is reduced in the modified form of the enzyme to the same extent as is the tetraiodofluorescein-induced activation . Thus, a relationship is demonstrated between the internal mechanisms by which ATP and tetraiodofluorescein activate aspartate transcarbamylase.

Proc Natl Acad Sci U S A, 1977 Jan, 74(1), 106 - 10
Nucleotide sequence of the operator-promoter region of the galactose operon of Escherichia coli; Musso R et al.; We have derived the nucleotide sequence of a segment of the operator-promoter region of the galactose operon of E . coli, by using a variety of DNA sequencing analyses . We have previously reported the sequence of the 5' terminal portion of gal mRNA {Musso, R . E., de Crombrugghe, B., Pastan, I., Sklar, J., Yot, P . & Weissman, S . (1974) Proc . Natl . Acad . Sci . USA 71, 4940-4944} and of the 59 base pairs preceding the startpoint of gal transcription (J . Sklar, S . Weissman, R . Musso, R . Di Lauro, & B . de Crombrugghe, submitted) . In conjunction with those results, the present data provide the sequence of the gal operator-promoter region . This sequence is compared with similar sequences in other promoters and operators . Tentative mechanisms for the regulation of the galactose operon are discussed.

J Med Chem, 1977 Jan, 20(1), 96 - 102
Quantitative structure-activity relationships of antimalarial and dihydrofolate reductase inhibition by quinazolines and 5-substituted benzyl-2,4-diaminopyrimidines; Hansch C et al.; A quantitative structure-activity relationship (QSAR) for the inhibition of dihydrofolate reductase from S . faecium by quinazolines has been formulated . This is compared with a QSAR for inhibition of E . coli dihydrofolate reductase by 2,4-diamino-5-benzylpyrimidines . The QSAR for inhibition of bacterial enzyme is compared with QSAR for mammalian enzyme inhibition . A QSAR has been formulated for the antimalarial action of quinazolines against P . berghei in mice . The antimalarial QSAR is consistent with that of the in vitro bacterial study.

J Gen Microbiol, 1977 Jan, 98(1), 17 - 27
The nature of the proteins present in the 'relaxed particles' from methionine-starved Escherichia coli A19 (Hfr rel met rns); Sykes J et al.; The 'relaxed particles' formed during methionine starvation of Escherichia coli A19 (Hfr rel met rns) have been isolated by large-scale rate-zonal density gradient ultracentrifugation . The proteins and rRNA species associated with these particles have been examined . The rRNA species present are precursor and mature forms of 16S and 23S rRNA . The bulk of the rRNA which accumulates during starvation is found within the particles . The proteins prepared directly from the particles give strong multiple immunoprecipitates with antisera specific to 30S and 50S ribosomal proteins . The soluble proteins, prepared and examined in the same manner, do not give this immunological reaction . Two-dimensional electrophoresis patterns of the proteins from the particles show that the proteins co-migrate with proteins from 30S and 50S ribosomes and are entirely dissimilar to the proteins prepared by the same methods from the soluble fraction of the cells . On the basis of these and other observations, it is concluded that the 'relaxed particles' are not artefacts but are arrested ribosome precursors containing both rRNA and certain ribosomal proteins . The free pool of ribosomal proteins is low in exponential-phase cells and is not significantly increased by a 2 h period of starvation for glucose . The implications of these observations concerning the proteins associated with 'relaxed' and 'chloramphenicol particles' are discussed in raltion to ribosome biogenesis and the stabilization of rRNA.

J Gen Microbiol, 1977 Jan, 98(1), 1 - 16
The nature of the proteins in 'chloramphenicol particles' from Escherichia coli A19 (Hfr rel met rns); Sykes J et al.; The unusual particles which accumulate in cell-free extracts from Escherichia coli A19 during chloramphenicol inhibition ('chloramphenicol particles') have been isolated by large-scale rate-zonal density gradient ultracentrifugation . The proteins and RNA species composing these particles have been examined . The rRNA species present are precursor and mature forms of 16S and 23S rRNA which accumulate during inhibition . The proteins prepared directly from the particles give strong multiple immunoprecipitates with antisera specific to 30S and 50S ribosomal proteins . The soluble proteins of the cell prepared in the same manner do not give this immunological reaction . Two-dimensional electrophoresis patterns of the proteins from the 'chloramphenicol particles' strongly resemble those for 30S and 50S ribosomal proteins, i.e . they are predominantly basic low molecular weight proteins, and are dissimilar to the patterns for the soluble proteins of the cell . It is concluded that the 'chloramphenicol particles' are a heterogeneous group of ribonucleoproteins comprising the bulk of the rRNA accumulating during inhibition in association with variable amounts of some of their corresponding ribosomal proteins . The particles are therefore not artefacts of preparation, as previously thought, but arrested ribosome precursors.

J Clin Microbiol, 1977 Jan, 5(1), 100 - 5
Inhibition of immune hemolysis: serological assay for the heat-labile enterotoxin of Excherichia coli; Evans DJ Jr et al.; Sheep erythrocytes sensitized by incubation with the heat-labile enterotoxin (LT) of Escherichia coli are hemolyzed in the presence of anti-LT antiserum and complement . The Microtiter (Cooke Laboratory Products) technique was used to titrate anti-LT antibody in serum by this immune hemolysis reaction . Immune hemolysis was inhibited by preexposure of the anti-LT antiserum to soluble LT before addition of the LT-sensitized sheep cells . E . coli mini-extract preparations were obtained by the polymyxin release technique and assayed for LT by the lysis inhibition test (LIT) and by the adrenal cell assay . All 75 adrenal cell-positive E . coli isolates were positive in the LIT assay . Eight of 318 adrenal cell-negative isolates tested were positive in the LIT assay, possibly indicating the presence of biologically inactive toxin.

Invest Ophthalmol Vis Sci, 1977 Jan, 16(1), 69 - 73
Mechanism of steroid action in ocular inflammation: Inhibition of prostaglandin production; Floman N et al.; Prostaglandin E (PGE) concentration the aqueous humor of an intact rabbit eye was less than 0.1 ng . per milliliter and increased to 19 +/- 3 ng . per milliliter 60 minutes following paracentesis . The rise in PGE level was associated with clinical signs of ocular inflammation . Pretreatment with triamcinolone reduced both the accumulation of PGE in the aqueous humor and the inflammatory response following paracentesis . intravitreal injection of E . coli endotoxin into rabbit eyes increases PGE level in the anterior chamber to 72 +/- 17 ng . per milliliter and induced acute uveitis . slices of iris and ciliary body (ICB) derived from either rabbit eyes with endotoxin-induced uveitis or normal eyes were incubated for 60 to 240 minutes and the rate of PGE release into the medium was measured by radioimmunoassay . after a 4 hour incubation, the PGE release from inflamed ICB was threefold higher than that of normal ICB . incubation of inflamed ICB with hydrocortisone, or Millicorten (100 mug per milliliter) for 4 hours reduced PGE accumulation in the medium by 50 and 81 per cent, respectively . Aldosterone had no effect on the rate of PGE release from inflamed ICB throughout the incubation period . Hydrocortisone or Millicorten also reduced PGE tissue content of inflamed ICB by about 74 per cent during the period of incubation . Indomethacin (100 mug per milliliter) abolished PGE accumulation . The suppressive action of hydrocortisone on PGE release into the incubation medium was prevented by the addition of arachidonic acid (2 mug per milliliter), a substrate for prostaglandin synthesis . By contrast , the inhibitory action of indomethacin was not affected by provision of arachidonic acid . We suggest that glucocorticosteroids reduce PGE accumulation by limiting the availability of the substrate for prostaglandin biosynthesis and thus suppress the inflammatory response.

Chemotherapy, 1977, 23 Suppl 1, 399 - 402
Neurosurgical infection treated with fosfomycin and 6-methylprednisolone; Gimeno L; A left parietal parasagittal meningioma was removed in a 67-year-old female patient . In the postoperative period she had a neurosurgical cerebral suppurating infection: subdural, epidural and epicranial, connected to the exterior by several fistulas . In the operative revision and after a culture, the germ causing the infection, E . coli, was isolated . Treatment was begun with 16 g of intravenous fosfomycin and 120 mg daily of 6-methylprednisolone intramuscularly, and this treatment cured the patient.

Am J Hosp Pharm, 1977 Jan, 34(1), 47 - 9
Quality control of small-volume sterile products; Rupp CA et al.; A method for bacterial surveillance of small-volume sterile products in hospitals was developed and tested . The criteria for the method of quality control were to: (1) assure detection of contamination associated with touch, which could occur during the filling process; (2) be economically feasible; (3) be simple and easy to implement; and (4) be versatile in adapting to small-volume sterile packages with and without needles . Ten percent of each lot of prepackaged unit dose syringes is tested by filtration through a sterile micropore filter . The filter unit is incubated after fluid thioglycollate medium has been added . If turbidity or color change is found, further testing with blood agar and gram staining is performed to identify the organism . The effectiveness of the method was tested by adding E . coli to one lot within each of several lots tested of six products . The inoculated samples were stored under refrigeration for three days before testing . With one exception, the E . coli was detected in the samples . Growth did not occur in any of the noninoculated units . The apparent false negative result was believed to be caused by the bacteriostatic agent killing the organism during the three-day storage period.

J Pediatr, 1977 Jan, 90(1), 29 - 35
Influence of the heat treatment of human milk on some of its protective constituents; Ford JE et al.; Human milk was subjected to heat treatments of graded severity and examined for its content of immunoglobulins, lactoferrin, lysozyme, vitamin B12-and folate-binder proteins, and lactoperoxidase . Holder pasteurization (62.5degrees C 30 minutes) reduced the IgA titer by 20%, and destroyed the small content of IgM and most of the lactoferrin . Lysozyme was stable to this treatment, but with an increase in temperature there was progressive destruction, to near 100% at 100degrees C . The same was broadly true of the capacity of milk to bind folic acid and potect it against bacterial uptake; with vitamin B12 the binder was more labile at 75degrees C than at 100degrees C . The milk contained no detectable lactoperoxidase.

J Bacteriol, 1977 Jan, 129(1), 66 - 70
Threonyl-transfer ribonucleic acid synthetase and the regulation of the threonine operon in Escherichia coli; Johnson EJ et al.; Two threonine-requiring mutants with derepressed expression of the threonine operon were isolated from an Escherichia coli K-12 strain containing two copies of the thr operon . One of them carries a leaky mutation in ilvA (the structural gene for threonine deaminase), which creates an isoleucine limitation and therefore derepression of the thr operon . In the second mutant, the enzymes of the thr operon were not repressed by threonine plus isoleucine; the threonyl-transfer ribonucleic acid(tRNA) synthetase from this mutant shows an apparent Km for threonine 200-fold higher than that of the parental strain . The gene, called thrS, coding for threonyl-tRNA synthetase was located around 30 min on the E . coli map . The regulatory properties of this mutant imply the involvement of charged threonyl-tRNA or threonyl-tRNA synthetase in the regulation of the thr operon.

J Bacteriol, 1977 Jan, 129(1), 540 - 3
Number of mutations required to evolve a new lactase function in Escherichia coli; Hall BG; The frequency of mutation of the ebgAo allele to ebgA+ was compared with the frequency of mutation of strA+ to strA- . The observation that both spontaneous and ethyl methane sulfonate-induced mutations to ebgA+ occurred more frequently than mutations to strA- suggests that ebgA+ mutants arise as the result of single-point mutations.

J Bacteriol, 1977 Jan, 129(1), 536 - 9
Fine-structure mapping of the rts, rplK, rplL, and rpoB genes of Escherichia coli; Bendiak DS et al.; The specialized transducing phage lambdacI857S7drifd18 was used as a donor in a transductional mapping of four genes in the rif region of the Escherichia coli genome . The gene order was rts-2.9-rplL-0.8-rpoB, where the numbers indicate intermarker distances in kilobases . The possible orientation of these genes with respect to each other and to neighboring genes is discussed.

J Bacteriol, 1977 Jan, 129(1), 482 - 91
Isolation, mapping, and examination of effects of TnA insertions in ColE1 plasmids; Inselburg J; Twelve TnA insertions of ColE1 deoxyribonucleic acid have been isolated and mapped by electron microscopic studies of heteroduplex molecules . Insertions only blocking the production of active colicin clustered in one region of the map, whereas insertions only blocking the expression of deoxyribonucleic acid nicking activity associated with the plasmid "relaxation complex" clustered in another region of the map . The location of one insertion that blocks both the expression of colicin immunity and the production of active colicin suggests that the expression of both characteristics are coordinately controlled.

J Bacteriol, 1977 Jan, 129(1), 407 - 14
Inhibition of TnA translocation by TnA; Robinson MK et al.; Plasmids already containing TnA showed decreased susceptibility to the translocation of a further TnA unit when compared with related plasmids that did not contain TnA . The translocation immunity imposed by TnA is exerted only on the plasmid of which it is part . It is suggested that this desensitization by a translocation unit is a general phenomenon that reduces the mutational effects of translocation.

J Bacteriol, 1977 Jan, 129(1), 378 - 87
Chemical measurement of steady-state levels of ten aminoacyl-transfer ribonucleic acid synthetases in Escherichia coli; Neidhardt FC et al.; Polypeptide chains of 10 aminoacyl-transfer ribonucleic acid synthetases (those for arginine, glutamine, glutamic acid, glycine, isoleucine, leucine, lysine, phenylalanine, threonine, and valine) have been identified in lysates of Escherichia coli resolved by the O'Farrell two-dimensional gel system . By labeling cells uniformly with {14C}glucose and by measuring the total amounts of these polypeptides by their radioactivity, estimations of the steady-state, molecular amounts of these enzymes were made and compared to the number of ribosomes and elongation factors in these cells . Portions of a reference culture grown on glucose and labeled with {14C}leucine or {35S}sulfate were mixed with four cultures grown in widely different media containing {3H}leucine or {3H}leucine plus {3H}isoleucine . From the isotope ratios of the total protein and of the spots containing the synthetase chains, the chemical amount of each synthetase relative to that of the reference culture was determined . The results, where comparable, show reasonable agreement with enzyme activity measurements . In general, these synthetases each exhibit a positive correlation with growth rate in unrestricted media, indicating a strong tendency for the levels of transfer ribonucleic acid, synthetases, elongation factors, and ribosomes to remain approximately, though not exactly, in balance at different growth rates.

J Bacteriol, 1977 Jan, 129(1), 358 - 66
New mini-ColE1 as a molecular cloning vehicle; Avni H et al.; A new mini-ColE1 plasmid, designated pAC105, was isolated . It has a molecular weight of 1.6 X 10(6) and carries information for its self-replication as well as information for conferring colicin E1 immunity upon its host . Furthermore, pAC105 undergoes replication in the presence of chloramphenicol even when a foreign deoxyribonucleic acid (pSC101) is inserted into its single EcoRI restriction site . Studies in minicell-producing strains demonstrate that pAC105 codes for only two or three polypeptides of low molecular weight . The advantages of using it as a molecular cloning vehicle are discussed.

J Bacteriol, 1977 Jan, 129(1), 225 - 36
Role of a sugar-lipid intermediate in colanic acid synthesis by Escherichia coli; Johnson JG et al.; Membrane fractions from a lon strain of Escherichia coli but not a wild-type strain catalyze the incorporation of fucose from guanosine 5'-diphosphate-fucose into a lipid and into polymeric material . Both incorporation reactions specifically require only uridine 5'-diphosphate (UDP)-glucose . The sugar lipid was shown to be an intermediate in the synthesis of the polymer which was related to colanic acid . The sugar lipid had the structure (fucose3, glucose2)-glucose P-P-lipid . Its behavior on column and thin-layer chromatography, the rates of its hydrolysis in acid and base, and the response of its synthesis to inhibitors are all identical to the other sugar-lipid intermediates which have been shown to contain sugars attached to the C55-polyisoprenol, undecaprenol, by a pyrophosphate linkage . The membrane fractions from both the lon strain and the wild-type strain also catalyzed the incorporation of either glucose from UDP-glucose or galactose from UDP-galactose into a lipid fraction which was shown to contain the free sugar attached by a monophosphate linkage to an undecaprenol-like lipid . This lipid was isolated and its nuclear magnetic resonance spectra was identical to undecaprenol . The membrane fractions from both strains also incorporated glucose from UDP-glucose into glycogen and into a polymer that behaved like Escherichia coli lipopolysaccharide . Conditions were found where the incorporation of glucose could be directed specifically into each compound by adding the appropriate inhibitors.

J Bacteriol, 1977 Jan, 129(1), 207 - 16
Transport and utilization of D-methionine and other methionine sources in Escherichia coli; Kadner RJ; The transport and utilization of D-methionine was investigated in several strains of Escherichia coli K-12 . Wild-type cells exhibit a single transport system with a Km of 1.16 muM . This activity exhibits a specificity similar to that of the uptake of L-methionine . The activity toward the D-isomer and the high-affinity uptake of L-methionine are lost in strains mutant in metD, along with the ability to utilize D-methionine as methionine source . Both activities respond identically to gene dosage of metD and are both restored in revertants or transductants . However, although L-methionine is a potent inhibitor of D-methionine uptake, D-methionine has little or no effect on the uptake of the L-isomer . No mutants altered in the uptake of only one of the two isomers were found in a screening . Regulation of both activities was similar in their response to the internal methionine pool, and some evidence was suggestive of partial repressive control of these activities . The evidence is most consistent with the role of the metD product as a common step for two methionine-specific uptake systems, but other gene products may represent the initial substrate binding sites . This system also appears to be involved in the uptake of N-acetyl methionine and methionine sulfoxide and methionine sulfoximine . The uptake of the keto analogue of methionine, alpha-keto-gamma-methiol butyrate, appears to be mediated by a separate system specific for alpha-keto straight-chain acids 5- to 6-carbon units in length.

J Bacteriol, 1977 Jan, 129(1), 145 - 50
Phospholipid composition and phenotypic correction of an envC division mutant of Escherichia coli; Michel G et al.; The cytoplasmic and outer membranes of a nonconditional chain-forming mutant, Escherichia coli PM61 envC, were separated by sucrose density gradient centrifugation . The phosphatidylglycerol/cardiolipin ratio in both membrane fractions was about one-third as high as in the parental strain P678 . The increased level of cardiolipin in PM61 membranes is the result of an alteration of the polyglycerophosphatide cycle . It was found that the turnover rate of phosphatidylglycerol is more rapid in PM61 than in the parental strain but that its cardiolipin turnover is not significantly different . The envC mutation can be corrected phenotypically by increasing the osmolarity of the medium . In the presence of 0.6 M sucrose, the population of PM61 is composed of short rods, and the phosphatidylglycerol/cardiolipin ratio is shifted to that of the parent . The phosphatidylglycerol turns over more slowly, whereas the cardiolipin turns over more rapidly in both strains . Thus, the increase of external osmolarity acts on phospholipid metabolism as well as on an unknown step involved in the mechanism of cell division of the envC mutant.

J Bacteriol, 1977 Jan, 129(1), 131 - 7
Effect of entry exclusion on mating aggregates and transconjugants; Eckerson HW et al.; Mating aggregates during conjugation directed by an F-like R factor in Escherichia coli were measured as the number of Lac+-Lac- sectored colonies present in a mating mixture . There is a high degree of correlation between the concentration of transconjugants produced in a mating mixture and the concentration of mating aggregates observed at several different concentrations of donor and recipient cells . The mating aggregates are sex pilus specific as demonstrated by the ability of donor-specific ribonucleic acid phage MS-2 to decrease both mating aggregates and transconjugants in a mating mixture . During entry exclusion by either a derepressed or a repressed F-like R factor, isogenic to the superinfecting R factor except for a resistance determinant, the number of transconjugants was markedly reduced, but the number of mating aggregates was not decreased . Entry exclusion by F-Gal toward the donor HfrH resembled that of the F-like R factor in that there was a reduction in the number of recombinants but no significant decrease in mating aggregates . These results suggest that entry exclusion inhibits conjugation at a stage after the formation of mating aggregates.

J Bacteriol, 1977 Jan, 129(1), 1 - 8
Isolation and characterization of Escherichia coli K-12 F- mutants defective in conjugation with an I-type donor; Havekes L et al.; Escherichia coli K-12 F- mutants defective in conjugation with an I-type donor (ConI-) were isolated and characterized . These mutants are specific in that they are conjugation proficient with other types of donor strains . They have an altered susceptibility to phages and detergents . Chemical analysis of the cell envelopes of mutant strains has shown that the lipopolysaccharide (LPS) is altered and that one major outer-membrane protein is absent . Conjugation experiments in which LPS from wild-type cells was added to a mating mixture, made up with wild-type donor and recipient cells, showed inhibition in transconjugant formation when an I-type donor, but not an F-type donor, was used . This strongly suggests that LPS of the recipient cell is directly involved in the ability to mate with an I-type donor but not with an F-type donor . The mutations are located in the 78- to 82-min region of the E . coli map, with one exception where the mutation maps near or in the galactose operon.

Gastroenterology, 1977 Jan, 72(1), 167 - 82
Pigment gallstones; Soloway RD et al.; Pigment gallstones are defined as any dark brown-to-black stone, consisting of calcium salts of bilirubin, phosphate, carbonate and other anions, and can be separated into carbonate- and noncarbonate-containing groups . Pigment stones predominate in the rural Orient, in cirrhosis, and in elderly United States patients undergoing cholecystectomy . Clinical associations include bile duct obstruction, stasis, and possibly hemolysis . Of pigment stones, 50% are radioopaque and account for two-thirds of all opaque stones . The concentrations of bile salts, phospholipids,, cholesterol, and total bilirubin in bile are similar to normal levels, but the concentration of unconjugated bilirubin is increased in the bile of some patients . Increased unconjugated bilirubin in bile may be caused by increased hydrolysis of excreted conjugated bilirubin . Unconjugated bilirubin is solubilized by bile salts, but the interaction is primarily nonmicellar . Ionized calcium and pH are important determinants of solubility . Sulfated glycoproteins, excreted in increased amounts in patients with cholelithiasis, may be the site of pigment stone precipitation because these compounds bind calcium salts tightly . E coli is frequently cultured from pigment stones in Japan but not in the United States; thus, bacterial beta-glucuronidase may be important in stone formation in Japan but probably not in the West . Stasis leads to increased calcium secretion and to increases in the concentration of sparingly soluble compounds that may then precipitate . Incomplete emptying of the gallbladder may result in the same concentration process . Unsaturated fats and chronic vagal stimulation cause pigment stone formation in animals . At present, surgery is the only treatment for pigment lithiasis.

J Exp Med, 1977 Jan 1, 145(1), 21 - 30
Characterization of self-reactive B cells by polyclonal B-cell activators; Primi D et al.; The existence of autoreactive B cells was predicted by theoretical considerations and, recently, confirmed by direct experiments . The aim of the present work was to investigate if the capacity of self-reactive B cells to be activated with different polyclonal B-cell activators (PBA) reflects the heterogeneity of the response as seen in all the Ig-positive cells . We injected mice with dextran sulfate, lipopolysaccharide from Escherichia coli 055:B5, and purified protein derivate of turbercle bacteria RT32 and studied the complement-dependent cytotoxicity against syngeneic spleen cells caused by the sera from injected mice with regard to the different parameters used for characterization of B-cell subpopulations . It was found that the capacity of self-reactive B cells to secrete antibodies reflects the polyclonal-activating capacity of the PBA used . The implications of these findings for the understanding of the triggering mechanism of B lymphocytes and for self-nonself discrimination are discussed.

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