Escherichia coli

Z Allg Mikrobiol, 1978, 18(6), 415 - 26
Kinetics of growth and substrate consumption of Escherichia coli ML 30 on two carbon sources; Hegewald E et al.; When E . coli ML 30 is grown in batch culture on a mineral salt medium containing a mixed carbon source of glucose and pyruvate, there is no sequential utilization of the carbon sources . The consumption of glucose and pyruvate takes place simultaneously with reciprocal influence (inhibition) on rates of substrate uptake . The specific growth rate is greater than mupmax for pyruvate but smaller than musmax for glucose . In the paper three cases of kinetics of growth and of substrate consumption at several combinations of initial substrate concentrations are considered . A mathematical model is proposed and investigated . The model allows to describe the growth on glucose or on pyruvate not only as singular carbon sources, but also as a mixed carbon source with reciprocal inhibition on rates of substrate uptake . By data fitting parameters of growth and substrate consumption were found.

Scand J Immunol, 1978, 8(4), 313 - 21
A chemical approach to the mechanism of B-lymphocyte activation . I . The pure presentation of haptens does not activate B lymphocytes; Vidal-Gomez J et al.; In an attempt to definitively determine whether the pure presentation of haptens (on repetitive, non-metabolizable carriers) to B lymphocytes triggers differentiation to antibody-producing cells, dinitrophenyl and trinitrophenyl groups have been covalently coupled to potentially inert carriers (polymethylmethacrylate, chlorinated polyethylene and cellulose) . The resulting conjugates (with three different degrees of hapten substitution) are not immunogenic . It is therefore concluded that the pure presentation of haptens to B lymphocytes does not trigger antibody formation.

Gynecol Obstet Invest, 1978, 9(1), 57 - 64
Experiments on prevention of the endotoxin-abortifacient effect by radiodetoxified endotoxin pretreatment in rats; Csordas T et al.; Endotoxemia has been induced in pregnant rats by intravenous injection of 1 mg Escherichia coli endotoxin which resulted in intrauterine death and abortion of fetuses in 24 h . The abortifacient effect of endotoxin was prevented in 90% by 200 microgram radiodetoxified endotoxin, injected intravenously 24 h earlier . The authors suppose that the radiodetoxified endotoxin can be a good tool also in the prevention of human septic (endotoxin) shock in pregnancy.

Acta Microbiol Acad Sci Hung, 1978, 25(3), 159 - 64
Haematologic effect and Shwartzman reactivity of radiodetoxified endotoxin; Szilagyi T et al.; Comparative experiments were made in rabbits with Escherichia coli O89 endotoxin and endotoxin detoxified by ionizing radiation (60Co-gamma, 5 Mrad) . Radiation significantly weakened the leukopenia and thrombocytopenia provoking effect of endotoxin . Radiodetoxified endotoxin decreased the fibrinogen level only slightly and caused insignificant changes in reptilase time . The complement level was decreased less by the detoxified than by the parent endotoxin . Even the local Shwartzman phenomenon inducing capacity of radiodetoxified endotoxin decreased significantly, particularly when it was used for preparation and provocation, too.

Vox Sang, 1978, 35(4), 219 - 23
Sandwich enzymoimmunoassay of hepatitis B surface antigen (HBsAg); Adachi H et al.; A sandwich enzymoimmunoassay (EIA) procedure was developed for the detection of HBsAg using Fab' of anti-HBsAg conjugated with beta-D-galactosidase from Escherichia coli with anti-HBsAg-coated silicone rubber discs as a solid phase . EIA could detect 1 ng/ml of HBsAg . It was as sensitive as radioimmunoassay (RIA, AusRia II) and about 30-fold more sensitive than reversed passive hemagglutination assay RPHA, ReverseCell) . EIA and RIA could detect more HBsAg-positive sera than RPHA.

J Nutr Sci Vitaminol (Tokyo), 1978, 24(3), 243 - 53
Enzymological properties of pantothenate synthetase from Escherichia coli B; Miyatake K et al.; Following a previous report on physicochemical properties, the enzymological properties of a homogeneously purified preparation of pantothenate synthetase were described . The optimum pH was 10.0 and optimum temperature 30 degrees C . The lyophilized enzyme was very stable on standing at -20 degrees C . K+ or NH4+ and Mg2+ were required as activators; other cations examined were inhibitive to various extents and the enzyme required ATP as the energy supplier . Some omega-amino acids exerted strong inhibition, and the enzyme was inhibited by some chelating agents but was not affected by SH compounds and SH inhibitors . Apparent Km for pantoate was 6.3 x 10(-5)M, for beta-alanine 1.5 x 10(-4)M, and for ATP 1.0 x 10(-4)M . According to the method of Cleland, the enzyme reaction proceeds by a Bi Uni Uni Bi Ping Pong mechanism and a scheme showing the order of binding of substrates and releasing of products is presented.

Folia Microbiol (Praha), 1978, 23(4), 278 - 85
Application of R-plasmid DNA's from Escherichia coli minicells in genetic transformation; Nesvera J et al.; Components of minicell lyzates of Escherichia coli P678.54 (R1 drd 19) and escherichia coli P678.54 (R6K) were visualized in an electron microscope and used for the transformation of Escherichia coli JC7623 . The frequency of the resulting transformants (of the order of 10(-6)%) was not appreciably influenced by the manner of lyzate preparation . The presence of covalently closed circular DNA was detected in two different transformants using radioisotopes, thus demonstrating an autonomous existence of R1 drd 19 or R6K plasmids in tested transformants . This finding corresponds with the results of their genetic analysis.

Biochimie, 1978, 60(4), 353 - 9
Biphasic saturations of binding proteins can be the result of a competitive inhibition of substrate fixation; Gaudin C et al.; A mathematical model is proposed which explains some biphasic saturations of Binding Proteins by their substrates through an effect of a competitive inhibition . The inhibitor can be the substrate itself especially when the retention phenomenon is occuring . This model has been verified with two periplasmic Binding Proteins of Escherichia coli: the Glutamine Binding Protein and the Leucine-Isoleucine-Valine Binding Protein . A significant connection is found between experimental results and the hypothesis.

Z Orthop Ihre Grenzgeb, 1978, 116(3), 331 - 6
{Local Sanarelli-Shwartzmann-phenomen after hemipelvectomy (author's transl)}; Weber U et al.; We report a case of haemorrhagic necrosis after hemipelvectomy, which shows nearly all characteritic criterions of local Sanarelli-Shwartzman-phenomenon.

Eur Surg Res, 1978, 10(3), 194 - 205
Effects of slow intravenous administration of endotoxin on blood cells and coagulation in dogs; Aasen AO et al.; Endotoxin shock was induced in dogs by slow administration of a lethal dose of Escherichia coli endotoxin . During the 3-hour infusion period a state of disseminated intravascular coagulation (DIC) was noted . The drop in platelets and leukocytes was the most rapid and pronounced effect of the infusion, while consumption of coagulation factors occurred more slowly . Activation of the extrinsic and intrinsic pathways of coagulation appeared to be closely parallel . Concomitantly increasing amounts of fibrin(ogen) degradation products were detected, while soluble fibrin monomers were observed only inconstantly . Intravascular hemolysis was slight and occurred in the late stages of shock, and could not have influenced the development of DIC.

Genetika, 1978, 14(7), 1278 - 80
{Localization of Rsf- mutation in Escherichia coli HfrC7}; Gukova LA et al.; The contransduction frequency of MAAs, UVs phenotype of Escherichia coli HfrC7 and its 7-51F- derivative with purE markers is found to be 1-2% which indicates that the mutation N 7 is located close to the F integration site in HfrC strain . E . coli strains K-12 7-51F+ and 7-51ColV2+ transfer chromosome markers in the same direction as does HfrC strain . The results suggest the presence of an integrated F fragment (sfa locus) into K-12 7-51F- chromosome.

Genetika, 1978, 14(7), 1164 - 74
{Construction and study of a new type of phage lambda DNA vector molecule}; Iankovskii NK et al.; A group of lambda mutants (mutants lambda 0) harbouring lesser number of EcoRI restriction sites on DNA molecules was selected . lambda3-1 recombinant (genotype lambdab221amgamma210Sr1lambda3+c-Px) was created by crosses of lambda02 phage with other lambda mutants . This phage DNA may be used as a vector molecule which makes it possible to select easily phages harbouring insertions of EcoRI DNA fragments . The maximal size of DNA fragment, the insertion of which would not decrease lambda3-1 viability, is 7.7 megadaltone . Lambda3-1 DNA has three regions heterological to lambda DNA, two of which probably include sites SRIlambda4 and SRIlambda5 and some juxtaposed genes . For example, Ptgene of lambda phage in juxtaposition with site SRIlambda4 is substituted by Px gene on the lambda3-1 DNA molecule.

Genetika, 1978, 14(7), 1127 - 45
{Problem of chromosome formation in T-even phages}; Mosevitskii MI; Three basic versions for the formation of circularly permuted and terminally redundant chromosomes with rings, concatemers, or fragments as replicative intermediates were considered . Experimental results show that the chromosome of T-even phage can turn into 4-6 large fragments soon after it penetrates inside the Escherichia coli cell . The fragments are capable for autonomous replication and contribute their material to progeny phage chromosomes . These results confirm the suggestion that circularly permuted and terminally redundant chromosomes of T-even phages are made of fragments . A theoretical analysis of different modes of parental chromosome fragments formation, autonomous replication and ordered association was carried out . In particular, it was emphasized that at a low multiplicity of infection the reassociation of fragments by means of recombination can be accomplished only if breaks in complementary strands of the parental chromosome were made with a shift for about 3000 nucleotides . Complexity is a feature of linear chromosomes that ensures their reproduction without defects at the ends.

Front Biol, 1978, 46, 143 - 60
Effects of cytochalasin B on endocytosis and exocytosis; Davies P et al.; The complex effects of cytochalasin B on endocytosis and exocytosis are reviewed . Cytochalasin B inhibits phagocytosis by both mononulcear phagocytes and polymorphonuclear leukocytes but it does not affect the micropinocytic activity of mononulear phagocytes and other cell types . Cytochalasin B causes increased selective release of acid hydrolase from phagocytic cells but its effect on other secretory cells is more variable, stimulating secretion by some cell types, inhibiting secretion in others and having no effect at all in some instances . The possible mechanisms of action of cytochalsin B are discussed with particular emphasis being placed on its effect on the activity of various protein components of cellular contractile systems . We suggest that many of the biolgoical effects of cytochalasin B may be accounted for by such effects.

Circ Shock, 1978, 5(2), 105 - 13
Hepatic oxygen supply and plasma lactate and glucose in endotoxic shock; Rink RD et al.; Hepatic oxygen supply and selected blood parameters were recorded in fasted male rates given 20--30 mg/kg Escherichia coli endotoxin intraperitoneally . Mortality was 70% within 24 hours . Measurements during the initial eight hours postendotoxin recorded no differences of hematocrit, systemic arterial pressure, or arterial pO2 between survivors and eventual nonsurvivors . However, by the sixth or eighth hour nonsurvivors showed significantly higher plasma lactate, lower plasma glucose and blood pH, and a greater degree of hypocapnea . In addition, a mean hepatic pO2 had decreased from 25.2 mm Hg during the control to 3.8 mm Hg after six hours . A decline of hepatic oxygen supply also occurred in surviving rats but was significantly less severe . Control rats showed a mild degree of respiratory alkalosis but were otherwise stable over eight hours . The relationship of hepatic oxygen supply to differences of plasma lactate and glucose is discussed . Failure of hepatic circulation is cited as the probable cause of extensive liver anoxia and related developments in nonsurviving endotoxic rats.

Prog Clin Biol Res, 1978, 22, 567 - 78
The kinetics of oxygen-induced proton efflux and membrane energization in Escherichia coli; Gould JM; The kinetics of respiration-dependent proton efflux and membrane energization have been studied in intact cells of logarithmic phase Escherichia coli . Proton efflux following a small O2 pulse is slow (t1/2 approximately equal to 10 sec) and inefficient (H+/O approximately equal to 0.5), taking 5-10 times longer than expected from the time required for the cells to reduce the O2 added in the pulse . A much closer agreement is found in cells treated to enhance counter ion fluxes and eliminate the transmembrane electric potential (deltapsi) . In cells treated with SCN-, or with colicin E1 (which enhances K+ permeability), the rates of proton efflux are much faster (t1/2 less than or equal to 1 sec) than in untreated cells . The kinetics of formation and dissipation of deltapsi were estimated from changes in the fluorescence properties of the cell envelope bound probe N-phenyl-l-naphthylamine . In untreated cells, a small O2 pulse induces a rapid (t1/2 less than or equal to 0.5 sec) decrease in fluorescence intensity followed by a slower (t1/2 approximately equal to 40 sec) return of the fluorescence to the original level . The extent of the initial fluorescence decrease is proportional to the amount of O2 added, although the half-time for the relaxation is independent of the amount of O2 added . Colicin E1 (plus K+) and the uncoupler FCCP greatly decrease the half-time of the relaxation, while only slightly affecting the extent of the initial decrease, indicating that the initial fluorescence decrease is reporting the energization of the membrane while its relaxation is reporting the subsequent deenergization of the membrane resulting from counterion redistributions . The fact that the efflux of H+ into the medium after an O2 pulse is small and much slower (t1/2 approximately equal to 10 sec) than the actual energization of the membrane (t1/2 less than or equal to 0.5 sec) suggests that the current of respiratory H+ involved in membrane energization is confined within the bacterial cell envelope.

Biokhimiia, 1978, 43(4), 761 - 3
{Spatial proximity of the ribosomal mRNA binding center to the 50S subunit}; Budker VG et al.; 4-(N-2-chloroethyl-N-methylamino)benzylamide of 5'-heptaadenylic acid was used for affinity labelling of the ribosome in the vicinity of its mRNA-binding centre . This derivative, similar to the free oligonucleotide, stimulates the binding of {14C}-lysyl-tRNA to ribosomes of E . coli and alkylates ribosomes both the 30S and the 50S subunits . The alkylation of ribosomes is inhibited by pre-incubation of ribosomes with polyadenylic acid, which suggests that the chemical modification is a specific one and occurs in the vicinity of mRNA-binding site . The fact, that a short oligonucleotide having an active group on its 5'end attacks the 50S subunit of ribosome may indicate that the mRNA-binding centre is located in the contact region between ribosomal subunits.

Biokhimiia, 1978, 43(4), 579 - 91
{Animal tissue polynucleotide phosphorylase}; Del'vig AA; Localization, physico-chemical and catalytic properties and possible biological functions of polynucleotide phosphorylase (PNPase) from animal tissues are discussed . In animal tissue cells PNPase has multiple localization; the major amount of the enzyme is localized in the endoplasmic reticulum ribosomes . In the nuclei PNPase, similar to other endo- and exo-RNAses participates in the processing of precursor molecules of mature forms of RNA, whereas in the cytoplasm it is involved in the destruction of polyribosomes in the polyribosomes of rapidly growing tissues the activity of PNPase is extremely decreased . The mechanisms regulating the PNPase activity in rapidly growing tissues are discussed.

Gastroenterol Jpn, 1978, 13(1), 33 - 42
Experimental colitis in rabbits; Kuroe K et al.; Experimental colitis was induced in rabbits either by immunizing the antigens which possess the cross-reacting antigenicity with colonic mucosa, and by infusing intravenously their own lymphocytes sensitized with E . coli 014 endotoxin which may contain a high concentration of common antigen (Kunin antigen) . The hemorrhagic inflammatory changes were developed in the colon as follows; (1) three of fifteen rabbits immunized with rat colon, (2) one of three rabbits with their own E . coli, (3) six of fifteen rabbits with E . coli 014 and, (4) five of eight rabbits by infusing their own lymphocytes sensitized with E . coli 014 endotoxin . It was suggested that the cross-reacting antigenicity with the colonic mucosa and the sensitized lymphocytes implicate in the pathogenesis of chronic ulcerative colitis.

Circ Shock, 1978, 5(1), 11 - 21
Glucose and lactate kinetics in guinea pigs following Escherichia coli endotoxin administration; Merrill GF et al.; Glucose and lactate turnovers were evaluated during the early stages (first three hours) of endotoxin-induced shock in unanesthetized male guinea pigs following the intravenous (IV) administration of 0.1 mg of Escherichia coli endotoxin . Rate of appearance (Ra), rate of disappearance (Rd), and metabolic clearance rate (MCR) of glucose and lactate were determined by the primed-constant infusion of {6-(3)H}-glucose and NA L(+){U-14C}-lactate . Arterial glucose concentration was moderately elevated, and the Ra and Rd of glucose were increased significantly following endotoxin administration, while the slight increase in MCR was not statistically significant . Arterial lactate concentration was markedly increased and the Ra and Rd of lactate were significantly elevated . The percentage of {14C}-glucose derived from {14C}-lactate increased from 19% (control) to above 50% following endotoxin . From these data we found no evidence of impaired peripheral extraction of glucose . The increased glucose Ra and the higher percentage of {14C}-glucose being derived from {14C}-lactate suggest increased gluconeogenesis during the early stages following endotoxin administration.

Avian Dis, 1978 Jan-Mar, 22(1), 10 - 5
Virulence of Escherichia coli strains for chicken embryos; Nabbut NH et al.; The virulence of 66 Escherichia coli strains was evaluated in 12-day-old chicken embryos inoculated by the allantoic route . The index of virulence used was the proportion of dead embryos within 3 days of inoculation . The strains were classified into "highly virulent," "moderately virulent," and "avirulent" groups . Although both virulent and avirulent strains grew equally well in vivo in the allantoic and yolk sacs, virulent E . coli invaded the whole embryo but avirulent ones failed to do so.

Arch Virol, 1978, 56(4), 309 - 15
Radioprotective activity of interferon inducers; Talas M et al.; The radioprotective activity of interferon inducers (tilorone, Acranil, poly I:C and LPS) was investigated against acute X-ray irradiation and prolonged 60Co-gamma rays irradiation . The endogenous spleen colony formation test and percentage of surviving mice 30 days after irradiation were used as indicators . All interferon inducers investigated proved to have radioprotective activity.

Nucleic Acids Res, 1978 Jan, 5(1), 257 - 69
1H NMR of valine tRNA modified bases . Evidence for multiple conformations; Kastrup RV et al.; Methyl and methylene protons of dihydrouridine 17 (hU), 6-methyladenosine 37 (M6A), 7-methylguanosine 46 (m7G), and ribothymidine 54 (rT) give clearly resolved peaks (220 MHz) for tRNA1val (coli solutions in D2O, 0.25 m NaCl, at 27 degrees C . Chemical shifts are generally consistent with a solution structure of tRNA1val similar to the crystal structure of tRNAphe (yeast) . At least 3 separate transitions are observed as the temperature is raised . The earliest involves disruption of native tertiary structure and formation of intermediate structures in the m7G and rT regions . A second transition results in a change in structure of the anticodon loop, containing m6A . The final step involves unfolding of the m7G and rT intermediates and melting of the TpsiC helix . Low salt concentrations produce multiple, partially denatured conformations, rather than a unique form, for tRNA1val . Native structure is almost completely reformed by addition of Na+ but Mg2+ is required for correct conformation in the vicinity of m7G.

Nucleic Acids Res, 1978 Jan, 5(1), 241 - 56
Application of a rapid gel method to the sequencing of fragments of 16S ribosomal RNA from Escherichia coli; Ross A et al.; A gel sequencing method has been applied to two 5' end-labelled fragments of the 16S ribosomal RNA from E . coli . The procedure involves partial enzymatic hydrolysis by ribonucleases T1, U2 or A, in order to generate series of end-labelled subfragments terminating in guanine, adenine, or pyrimidine residues, respectively . The two fragments concerned were approximately 75 and 90 nucleotides in length, and both arose from the 3' region of the 16S RNA . The sequences deduced are compared with the published sequence of 16S RNA, and contribute information to the final ordering of the ribonuclease T1 oligonucleotides in the latter, as well as revealing some probable errors.

Morphol Igazsagugyi Orv Sz, 1978 Jan, 18(1), 4 - 9
{X-ray microanalysis of Michaelis-Gutmann bodies with the use of EDAX}; Kuthy E et al.; X-ray microanalysis of Michaelis--Gutmann bodies in human malakoplakia (kidney and testes) and in that of rats induced experimentally by administration of endotoxin of Escherichia coli, was carried out . The presence of calcium could be revealed in every Michaelis--Gutmann body according to the lines of Kalfa and K3 as well . The amount of it was in correlation with the stage of the calcification . In the Michaelis--Gutmann bodies found in the rat kidney, fixed without OsO4 presence of P could also be demonstrated . The correlation between the weight per cent of Ca and P seems to evidence the presence of CaHPO4 . Results of the X-ray microanalysis of Michaelis--Gutmann bodies found in human and in experimentally induced malakoplakia appeared to be similar.

Mol Biol (Mosk), 1978 Jan-Feb, 12(1), 191 - 205
{Effect of several factors on synthesis of RNA-polymerase subunits by Escherichia coli K12}; Bass IA et al.; In merodiploid cells containing a double dose of structural genes of RNA polymerase subunits--rpoB and rpoC--the rate of synthesis of beta- and beta'-subunits is 2 times higher than in haploid cells . Missense mutation rpoC1 (tsX) in the beta'-polypeptide gene accelerates the synthesis of both beta- and beta'-subunits, particularly at a nonpermissive temperature . When rpoB-rpoC operon containing mutation rpoC1 is duplicated no dose effect of these genes is observed . In the heterozygous state mutation rpoC1 produces almost no accelerating effect on the synthesis of RNA polymerase subunits i . e . is recessive with respect to the wild allele of rpoC . In the presence of rifampicin the synthesis of RNA polymerase subunits in a sensitive wild-type strain is stimulated 6-fold, the same effect is observed with cells carrying mutation rpoC1, the latter, however, itself accelerates the synthesis of these subunits 3-fold . Thus the effects of rifampicin and the mutation are synergistic indicating that these factors act independently . Similar data have also been obtained with rifampicin-treated cells of rpoB22 amber-mutant . In UV-irradiated cells, amino acid incorporation into beta- and beta'-subunits declines more rapidly than into the total protein . When either irradiated or non-irradiated cells are infected with a transducing phage lambdarifd-47 which carries rpoB gene, the synthesis of beta-proceeds at a higher rate . Irradiation of bacteria before the infection (500 erg/mm2) results in 6.5-fold acceleration of the synthesis induced by subsequent infection with lambdarifd-47 as compared to non-infected non-irradiated cells; the fraction of newly formed beta-polypeptide with respect to total protein grows 20-fold in this case . The data are considered with regard to the possible mechanisms of regulation of synthesis of RNA polymerase subunits.

Mol Biol (Mosk), 1978 Jan-Feb, 12(1), 165 - 78
{Interaction of DNA with RNA-polymerase from Escherichia coli cells infected and uninfected with T2 phage}; Zaitsev IZ et al.; RNA polymerase from T2 infected E . coli has greatly reduced activity as compared to the enzyme from uninfected bacteria . Nevertheless both RNA polymerases synthesize heterogenous RNA species with the same maximum corresponding to chain length of 5600 nucleotides on T2 DNA . Rifampicin-challenge experiments suggest that these enzymes have identical kinetics of RNA chain initiation and elongation but their ability to form rapidly starting (RS) and delay starting (I) binary complexes with phage DNA are different . The temperature of I leads to RS transition on T2 DNA is 15 degrees for E . coli holoenzyme, but is 35 degrees for the RNA polymerase from infected cells . The transition temperature depends both on the core and on sigma fraction . Shift temperature technique was developed to investigate the kinetics of I in equilibrium RS complexes rearrangements and their temperature dependence . The rate of these rearrangements is strongly temperature dependent for E . coli holoenzyme, while for RNA polymerase from infected cells it is much lower and is practically temperature independent . From the kinetic data and from the temperature dependence of equilibrium RS-complexes concentration, the rate constants of RS-complexes formation and decay are calculated . The kinetic data obtained in rifampicin challenge experiments are in agreement with the data on the dissociation of DNA-enzyme complexes performed by the filter assay.

Mol Biol (Mosk), 1978 Jan-Feb, 12(1), 135 - 46
{New method of determining parameters of oligonucleotide complex formation with nucleic acids according to the results of alkylation in complexes . Comparison with the method of equilibrium dialysis}; Grineva NI et al.; Binding constants of oligonucleotides with nucleic acids can be determined using data of nucleic acids alkylation with 2',3'-O-4-(N-2-chloroethyl-N-methylamino)benzylidene oligonucleotides . The latter bind to complementary sequences of nucleic acids, the binding constants of which are close to that of oligonucleotides . The extent of alkylation allows to determinate the equilibrium concentration of the binding with small corrections by an equation given, and hence to estimate the binding constants by standard modes . The binding constants of oligoadenylate and oligocytydilate derivatives with 23S RNA and rRNA have been determined at 0 degrees and 20 degrees by the method suggested and by the method of equilibrium dialysis . The binding constants are consistent of the magnitudes, as well as of the plots of the binding constants versus the oligomer and RNA concentrations and versus the oligomer length . The data obtained indicate that alkylation within the complexes of tri-hexamers with rRNA proceeds under the condition of an established equilibrium . Limits of the method suggested are evaluated.

Mol Biol (Mosk), 1978 Jan-Feb, 12(1), 108 - 15
{Construction and molecular cloning of hybrid plasmids containing specific fragments of Escherichia coli DNA}; Kozlov IuI et al.; In the paper a convenient procedure for the isolation of specific Eco RI-fragments of E . coli genome and their amplification on Km-resistance plasmid vector CKdelta11 is described . Plasmid CKdelta11 contains Col E1 replicon and has only one Eco RI site . The hybrid molecules were constructed in vitro using Eco RI-digestion followed by ligation . Then appropriated E . coli strain (polyauxotrophic strain E . coli K12 AB 2463) was transformed with ligated DNA mixture and hybrid plasmids, containing arg, leu, his and thr chromosomal markers were selected by molecular cloning and isolated from the obtained E . coli clones . The hybrid plasmids have two Eco RI sites and consist of one Eco RI-fragment of initial plasmid CKdelta11 and one Eco RI-fragment of El coli DNA . The method described allows to isolate and amplify on hybrid plasmids DNA fragments, containing any selectable genes or genes adjacent to the selectable ones.

Invest Radiol, 1978 Jan-Feb, 13(1), 21 - 5
Effect of endotoxemia on contrast media reactions; Slivka J et al.; Since complement activation is sharply temperature-dependent, we have examined the effects of fever produced by a very small dose of endotoxin on contrast media lethality in rabbits . After the injection of 8.2 ml/kg of 52% methylglucamine iodipamide, a group of rabbits exhibiting an average temperature elevation of 1.5 degrees C had a 100% mortality rate . This was contrasted to a 30% mortality in control rabbits receiving contrast alone, and no mortality in rabbits receiving endotoxin alone . The rabbits with fever and increased mortality exhibited increased activation of serum complement . From this preliminary data it appears that caution should be observed in performing a contrast examination in a patient with endotoxemia and/or a fever.

Eur Surg Res, 1978, 10(1), 50 - 62
Plasma kallikrein activity and prekallikrein levels during endotoxin shock in dogs; Aasen AO et al.; Endotoxin shock (ES) was induced in Labrador retriever dogs by infusion of a lethal dose of Escherichia coli endotoxin . Spontaneous plasma kallikrein activity and prekallikrein levels were determined during subsequent stages of the shock both by an esterolytic assay (BAEe) and a new amidolytic assay utilizing a chromogenic tripeptide derivative (Chromozym PK, Prntapharm AG, Basel Switzerland) . During the late stages of shock characterized by a substantial decline of blood pressure, plasma prekallikrein levels determined by the amidolytic assay were considerably reduced . In this phase of the shock both the esterolytic and the amidolytic assays revealed a significant elevation of spontaneous activity . Plasma prekallikrein determined by the esterolytic assay was found to be elevated vs . control values for the whole duration of ES . The findings made seem to associate activation of the plasma kallikrein-kinin system to the circulatory collapse of endotoxin shock in dogs.

Biochem J, 1978 Jan 1, 169(1), 247 - 9
Recognition of individual Escherichia coli transfer ribonucleic acids by 1-adenine-specific methyltransferase from rat liver; Kraus J; Purified 1-adenine-specific tRNA methyltransferase from rat liver preferentially methylated Escherichia coli tRNA species containing the target adenylate residue in a G-T-psi-C-G-A-A-U-C sequence . The results of methylation of various tRNA species are discussed.

Vet Pathol, 1978 Jan, 15(1), 92 - 101
Pathological changes in the small intestine of neonatal calves with enteric colibacillosis; Pearson GR et al.; Three neonatal calves, protected from colisepticaemia by intravenously administered immunoglobulin M, were infected orally with Escherichia coli type 0101 K?(A) . All calves developed severe enteric colibacillosis . When they were 4 days old stunting and fusion of villi were seen in the distal half of the small intestine and were associated with adhesion of the challenge organism to the mucosa . Two uninfected control calves kept under similar conditions, did not develop diarrhoea and had no lesions.

Urologe A, 1978 Jan, 17(1), 5 - 9
{Occult reflux (author's transl)}; Kollermann MW et al.; Level diagnosis repeatedly performed in patients without roentgenologically demonstrable reflux demonstrated bladder bacteriuria in 80% of the cases . The remaining 20% had supravesical bacteriuria . We called this occult reflux, if reinfection was demonstrated . Contamination of the upper tract by occult reflux can, but must not induce pyelonephritis . Bilateral antireflux surgery frequently eliminates occult reflux of bacteria, so this seems a debatable method of treatment.

Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 270 - 4
Electron microscopic determination of the binding sites of ribosomal proteins S4 and S8 on 16S RNA; Cole MD et al.; Specific complexes.early in the assembly of Escherichia coli ribosomes were examined in the electron microscope . Complexes between ribosomal protein S4 or S8 and 16S RNA were fixed gently with formaldehyde and then denatured for protein-free spreading . Binding of each protein was found to preserve an easily recognized configuration in the RNA that allows the sites of protein binding to be determined . S8--16S RNA complexes have a single hairpin loop near the middle of the 16S RNA, 798 +/- 21 bases from one end and 657 +/- 26 bases from the other . S4-16S RNA complexes have two adjacent loops at one end with 250--450 bases . This structure probably arises from the simultaneous binding of S4 to three noncontiguous sites on the RNA . Measurements of these complexes place the binding sites near the 5' end, at more than one site 250--585 nucleotides from the 5' end and 645 +/- 45 bases from the 3' end . The latter site has not been recognized previously as a distinct S4 binding site . This approach allows the binding sites to be determined without knowledge of the nucleotide sequence and gives insight into the configuration of the rRNA in the assembling ribisome.

Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 190 - 4
Structure of yeast phenylalanine-tRNA genes: an intervening DNA segment within the region coding for the tRNA; Valenzuela P et al.; Sixteen bacterial clones containing sequences complementary to yeast PhetRNA were isolated from a collection of hybrid plasmids containing BamHI restriction endonuclease-generated yeast DNA fragments inserted in the plasmid vector pBR315 . Ten of these clones contained hybrid plasmids with distinct BamHI fragments . The sequence of the Phe-tRNA structural genes and adjacent regions of three of these clones is reported here . In the region flanking the tRNA gene, the sequence of two of the cloned DNAs is similar; the sequence of the third varies considerably . All three of the tRNA genes are bordered by A,T-rich regions . In particular, near the region coding for the 3' end of the tRNA there is a long sequence of As in the coding strand . This is reminiscent of the region of termination of transcription of the yeast 5S rRNA gene . The sequences coding for the Phe-tRNA contain an additional segment of 18 or 19 base pairs (depending upon the clone) not predicted by the yeast Phe-tRNA sequence . These intervening segments are nearly identical in the three clones and are located within the structural gene, two base pairs from the nucleotides coding for the tRNA anticodon.

Postgrad Med J, 1978 Jan, 54(627), 33 - 5
Effect of noxythiolin on experimental peritonitis; Gilmore OJ et al.; The intraperitoneal instillation of noxythiolin in the treatment of peritonitis is widespread in clinical practice despite contradictory evidence as to its efficacy . In this light the value of noxythiolin was reappraised by studying its effect in guinea-pigs and mice with induced bacterial peritonitis . Treatment with a 1% solution of noxythiolin reduced the mortality rate of mice by 14% (P less than 0.1) . The guinea-pig model proved unreliable giving inconsistent mortality rates throughout . Further studies are required to determine the optimum dose and concentration of noxythiolin while the search for more effective intraperitoneal antiseptics should continue.

Mutat Res, 1978 Jan, 56(3), 225 - 34
The efficiency and extent of mutagenic activity of some new mutagens of base-analogue type; Janion C; N4-Hydroxycytidine, 5-methyl-N4-hydroxydeoxycytidine and 2-amino-N6-hydroxyadenine were tested for their mutagenic activity in S . typhimurium and E . coli cells . Reversion analysis of different markers was applied in a plate-test system, and 2-aminopurine was used as a reference mutagen . (i) 2-Amino-N6-hydroxyadenine was the most potent mutagen . In some cases it gave more than 1000 colonies of revertants per plate . (ii) N6-Hydroxycytidine was the least specific mutagen . Almost all the tested markers were inducible to revert by this analogue . (iii) The mutagenic specificity of 5-methyl-N4-hydroxydeoxycytidine seemed to be opposite to that of 2-aminopurine . This suggests that the former can induce transition of CG to TA . (iv) A comparison of the mutagenic actions of N4-hydroxycytidine and 5-methyl-N4-hydroxy-deoxycytidine showed that deoxyriboside analogues are not necessarily more efficient mutagens than ribonucleosides . (v) No purine or pyrimidine deficiency was needed for mutagenesis to occur for any of the mutagens investigated . (vi) The results on bacteria with different repair abilities suggest that base-analogue mutagenesis (except perhaps for BrdUrd) occurs mainly during replication of nucleic acids containing substituted nucleosides with bi-functional specificity.

J Exp Med, 1978 Jan 1, 147(1), 39 - 49
Genetic control of endotoxic responses in mice; Watson J et al.; A number of altered immunologic responses to lipopolysaccharide (LPS) in C3H/HeJ mice result from the expression in B lymphocytes of a defective genetic locus, termed Lps . Lps has been mapped to chromosome 4 between two loci, Mup-1 and Ps . As it is difficult to type individual mice for LPS responsiveness in more than one type of assay, we have utilized Mup-1 as a genetic marker to correlate LPS responses in mice to the expression of the Lps locus . Three nonlymphoid responses to LPS have been examined in 12 recombinant inbred strains of mice and in a backcross linkage analysis, and are all regulated by the expression of the Lps locus . These responses are hypothermal changes in body temperature, and the elevation in serum levels of a colony stimulating factor and the precursor of the secondary amyloid protein AA . Therefore, the initiation of LPS responses in different cell types in mice involve the expression of a common locus . These linkage studies provide a means for analyzing the genetic control of many of the diverse reactions of the endotoxic response to LPS.

Hoppe Seylers Z Physiol Chem, 1978 Jan, 359(1), 89 - 101
tRNA isopentenyltransferase from Zea mays L . Characterization of the isopentenylation reaction of tRNA, oligo (A) and other nucleic acids; Holtz J et al.; The extraction and purification of the tRNA isopentenyltransferase from maize root tips and kernels are reported . The relative amounts of this enzyme in different organs of maize have been determined . Root tips have the highest enzyme activities, followed by kernels and young leaves . Old leaves exhibit very low activity . The molecular mass of the monomeric enzyme was determined to be 57000 - 63000 dalton . pH and Mg2 optima are in full agreement with the data reported for the enzymes from yeast and Escherichia coli . Spermine enhances the isopentenylation of tRNA from kernels . The "Km" values of KMnO4-treated or untreated bulk tRNA from yeast and maize root tips and kernels were in the range of 10 to 34 micrometer while the Km values of of single species like tRNASer4 from rat liver and tRNATyrKMnO4 from E . coli were 1.1 and 6.6 micrometer, respectively . The tRNA isopentenyltransferase from maize root tips and kernels catalyzes the incorporation of 2-isopentenyl groups into (Ap)3-7A, endogenous bulk oligonucleotos from maize root tips and kernels, and into poly(A), RNA from MS-2 phages and, to a very low extent, into adenosine . The Km values of (Ap)3-7 A varied in the range of 250 to 750micrometer . Although oligonucleotides have less affinity to the enzyme, the formation of i6A within oligonucleotides may occur in vivo, due to their higher concentrations in cells.

Genetika, 1978, 14(1), 111 - 21
{Allele specificity of genetic recombination in T4 phage using the indicator crossing study method}; Shcherbakov VP et al.; The diagrams of relative correction ability of eighteen rII mutants of T4 phage were constructed on the basis of two-factor crosses, which were grouped into indicator series . In each series a pair of closely linked compared markers was crossed against indicator ones, the latter being distant enough so as to avoid simultaneous correction with the compared marker . The differences between the frequencies of wild type recombinants in crosses of two compared markers with indicator ones remained constant within the series and can be used as a measure of the differences between the compared markers in their correction ability . Mutants of base substitution type have small but statistically significant differences in correction ability . Simultaneous substitution of two bases in one codon yields a mutant which shows higher correction ability when compared to the mutant obtained as a result of substitution of only one base in the same codon . Frame shift mutants show much wider range of correctibility: some of them are corrected more rarely and others more frequently than base substitution mutants are.

Biokhimiia, 1978 Jan, 43(1), 17 - 22
{Determination of leucine-binding protein content of Escherichia coli cells}; Arsen'eva EA et al.; A radioimmunochemical method of determination of leucine-binding protein and a method, based on the selective absorption of the protein and its complex with leucine on DEAE-cellulose, has been developed . The protein content in the E . coli cells at different stage of growth has been determined by the radioimmunochemical and equilibrium dialysis methods . It was shown that the protein content in the cells is practically independent of the growth-phase.

Arthritis Rheum, 1978 Jan-Feb, 21(1), 45 - 50
Effect of systemic lupus erythematosus antibodies against DNA on RNA synthesis; Makarova OV; The majority of tested systemic lupus erythematosus (SLE) sera inhibited RNA synthesis in vitro on the stage of RNA chain elongation . Two sera were also active in inhibiting the binding of the enzyme to the template . No correlation has been found between the sera activity in filter radioimmunoassay, their specificity to double- or single-stranded DNA, and the degree of RNA synthesis inhibition.

Appl Environ Microbiol, 1978 Jan, 35(1), 6 - 10
Breaks induced in the deoxyribonucleic acid of aerosolized Escherichia coli by ozonized cyclohexene; De Mik G et al.; The inactivation of aerosolized Escherichia coli by ozone, cyclohexene, and ozonized cyclohexene was studied . The parameters for damage were loss of reproduction and introduction of breaks in the deoxyribonucleic acid (DNA) . Aerosolization of E . coli in clean air at 80 percent relative humidity or in air containing either ozone or cyclohexene hardly affected survival; however, some breaks per DNA molecule were induced, as shown by sucrose gradient sedimentation of the DNA . Aerosolization of E . coli in air containing ozonized cyclohexene at 80 percent relative humidity decreased the survival by a factor of 10(3) or more after 1 h of exposure and induced many breaks in the DNA.

Ann Clin Lab Sci, 1978 Jan-Feb, 8(1), 30 - 3
Inhibition of human neutrophil chemotaxis by corticosteroids; Shea C et al.; A direct inhibitory effect of hydrocortisone on granulocyte chemotaxis has been demonstrated with an increasing inhibition between concentrations of 5 microgram to 12.5 microgram per ml . Washing the granulocytes after incubation with hydrocortisone did not reverse the inhibitory effect on chemotaxis indicating a direct cellular effect . Bacteriocidal capacity of the hydrocortisone treated cells was not reduced . These studies indicate corticosteroids, alter motility of granulocytes irreversibly possibly by incorporation into the cell membrane.

Am J Public Health, 1978 Jan, 68(1), 68 - 70
Antibody to Escherichia coli enterotoxin in meat-packing workers; Wallace RB et al.; Meat-packing plant employees exposed to raw animal products had serological evidence of higher infection rates with heat-labile toxin producing enterotoxigenic Escherichia coli (LT-EEC) . In those employees with multiple sera available for study over a ten-year period, a drop in mean anti-LT-EEC titer was observed, suggesting altered ecology of or exposure to the organism during this time . Prospective studies need to be done to determine if meat-packing workers actually experience a greater incidence of LT-EEC-induced diarrheal disease.

Mutat Res, 1978 Jan, 49(1), 9 - 18
Mode of mutagenic action of 4-benzoylamido- and 4-acetamido-4-carboxamido-n(N-nitroso)-butylcyanamide; Otsuji N et al.; The mode of mutagenic action of 4-benzoylamido- and 4-acetamido- 4-carboxamido-n(N-nitroso)-butylcyanamide (BCNBC, ACNBC) was studied using Escherichia coli K12 strains . The strains carrying defects in DNA-repair mechanism, AB2463 (recA) and P3478 (polA) were more sensitive than their parent strains to both compounds, while AB1886 (uvrA) showed the same sensitivity as the parental strain . About 90% of tryptophan revertants from BE1043 (trpambphoamb) by both compounds were due to mutation in suppressor genes . Suppressor analysis by using BE1047 (trpambphooch) revealed that the most frequently occurring reversion was due to a mutation in suppressor gene, supE . This implies that these two alkylnitrosocyanamides predominantly induce GC leads to AT transition.

Mutat Res, 1978 Jan, 49(1), 1 - 8
An evaluation of Tween 80 effects on the survival and DNA repair in Escherichia coli following UV or gamma irradiation; Chi RK et al.; The notion that Tween 80 may be a DNA-repair inhibitor was tested with Escherichia coli . The results indicate that cell growth, colony-forming ability, and the rate and extent of removal of thymine-containing dimers from DNA are unchanged in the presence of Tween 80 . We conclude that this detergent does not increase or diminish the effect of UV or gamma irradiation to bacteria.

J Nucl Med, 1978 Jan, 19(1), 36 - 43
Studies on gallium accumulation in inflammatory lesions: I . Gallium uptake by human polymorphonuclear leukocytes; Tsan MF et al.; The mechanism of ionic gallium-67 localization in inflammatory lesions was studied . Human polymorphonuclear leukocytes (PMN) had higher Ga-67 uptake than lymphocytes, whereas red blood cells had no affinity for Ga-67 . Uptake by PMN showed temperature dependence, was independent of Ga-67 concentrations, and was not inhibited by metabolic inhibitors . However, its binding to PMN could be removed by trypsin but not by neuraminidase . These results are consistent with the hypothesis that the plasma membrane serves as a diffusion barrier and Ga-67 only binds to the surface of the PMN plasma membrane . When this membrane's permeability barrier was disrupted, as in heat-killed PMN, Ga-67 uptake increased markedly . Experimental abscesses were induced with E . coli or turpentine in rabbits . Twenty-four hours after i.v . injection, only 20% of Ga-67 in abscesses was in fractions containing intact PMN, cell debris or bacteria; the remainder was in a soluble, non-cellular fraction (2,500-g supernatant).

Cell, 1978 Jan, 13(1), 73 - 81
On the nature of tetracycline resistance controlled by the plasmid pSC101; Tait RC et al.; In vitro enzymatic alteration of plasmid phenotype and in vitro construction of recombinant plasmids containing genetic information derived from the plasmid pSC101 have been used to investigate the mechanism of function of tetracycline resistance determined by the plasmid pSC101 . The resistance has been shown to be inducible and involves the increased synthesis of membrane-associated polypeptides of 34,000, 26,000 and 14,000 daltons that are encoded for by the plasmid . The 34,000 dalton polypeptide along with another plasmid-encoded polypeptide of 18,000 daltons function in an ATP-independent manner to prevent the accumulation of tetracycline by the cell . These polypeptides are sufficient for resistance . A second component of plasmid-determined resistance involves the 14,000 dalton polypeptide and reduces the initial adsorption of tetracycline by sensitive cells, but is not alone sufficient for the generation of resistance . The role of the 26,000 dalton polypeptide in tetracycline resistance has not been identified.

Am J Pathol, 1978 Jan, 90(1), 7 - 22
The effects of indomethacin on the generalized shwartzman reaction; Howes EL Jr et al.; The antiflammatory drug indomethacin, an inhibitor of prostaglandin synthesis, prevents the generalized Shwartzman reaction produced in rabbits by two intravenous injections of bacterial endotoxin . Indomethacin has this effect if given before the first but not the second injection of endotoxin . Measurements of circulating white blood cells, platelets, partial thromboplastin time, prothrombin time, fibrinogen, plasminogen, and soluble fibrin were made at several times after either the first or second injection of endotoxin treated and nontreated rabbits . Four hours after the first injection of endotoxin, leukopenia and thrombocytopenia were somewhat greater in treated rabbits and the prolongation of the activated partial thromboplastin time was shortened . Twenty-one hours after injection of endotoxin, leukocytosis and elevation of plasma fibrinogen were not as great in treated animals . Four hours following the second injection of endotoxin a decrease in fibrinogen, prolongation of the prothrombin time, and the elaboration of soluble fibrin were consistently found in rabbits with the generalized Shwartzman reaction . In treated rabbits, none of these changes occurred . Indomethacin prevents the generalized Shwartzman reaction by preventing the development of the prepared state in this endotoxin model.

J Clin Pharmacol, 1978 Jan, 18(1), 61 - 6
Evaluation of amoxicillin therapy in ill children; Marks MI et al.; Ampicillin and amoxicillin were evaluated in 37 ill children . Detailed pharmacokinetic studies in 27 of these children demonstrated an advantage in oral absorption of amoxicillin over ampicillin at dosages of both 12.5 and 25 mg/kg per dose . Individual variation was great for both drugs . No sequence effect was noted for patients receiving ampicillin before either ampicillin or amoxicillin . Amoxicillin was tolerated well by the majority of patients, and the drug was not discontinued because of side effects in any patient . No toxicities were noted for amoxicillin in any of the 20 patients studied for abnormalities in hematologic hepatic, and renal functions . Pharmacokinetics, clinical efficacy, tolerance, and toxicity studies support the clinical usage of amoxicillin in pediatric infectious diseases . However, comparative, controlled clinicalinvestigations are needed to better define the clinical advantages of this drug over ampicillin.

J Bacteriol, 1978 Jan, 133(1), 81 - 4
Gene dosage effects of the structural gene for a lipoprotein of the Escherichia coli outer membrane; Movva NR et al.; The gene dosage effects of the structural gene (lpp) for the lipoprotein of the Escherichia coli outer membrane were examined . A novel F-prime factor containing the lpp gene was constructed . The amount of the free-form lipoprotein in the merodiploid strain carrying the F-prime factor was found to be about two times as great as that in the corresponding haploid strain . On the other hand, the amount of the bound-form lipoprotein, which is vovalently linked to the peptidoglycan, was not significantly different in the merodiploid strain as compared with the corresponding haploid strain . The present results suggest that the lpp gene is expressed constitutively in contrast to another major protein of the E . coli outer membrane, tolG protein (protein II, D . B . Datta et al., J . Bacteriol . 128:834-841, 1976) . The F-prime factor isolated may include a portion of the E . coli chromosome (located between 33 and 36 min on the genetic map) that is not covered by any other F-prime factor.

J Bacteriol, 1978 Jan, 133(1), 75 - 80
Single-strand breakage in DNA of Escherichia coli exposed to Cd2+; Mitra RS et al.; When a growing culture of Escherichia coli was exposed to 3 X 10(-6) M Cd2+, 85 to 95% of the cells lost their ability to form colonies on agar plates . Loss of viability was accompanied by considerable single-strand breakage in the DNA, with no detectable increase in double-strand breaks . A direct correlation appeared to exist between the number of single-strand breaks and the concentrations of Cd2+ to which the cells were exposed . Exposure of DNA in vitro to a Cd2+ concentration of 3 X 10(-6) M or higher, followed by sedimentation in alkaline sucrose gradients, demonstrated no single-strand breaks . Cadmium-exposed cells recovered viability when incubated in Cd2+-free liquid medium containing 10 mM hydroxyurea . During the early period of recovery, there was a lag in the incorporation of labeled thymidine, but cellular DNA, at least in part, appeared to be repaired.

J Bacteriol, 1978 Jan, 133(1), 442 - 5
F- mating materials able to generate a mating signal in mating with HfrH dnaB(Ts) cells; Ou JT et al.; The purified outer membrane from F- (W1-3) cells was shown to inhibit mating effectively, but the purified cytoplasmic (inner) membrane did not . These membranes, heat-treated minicells, and ultraviolet-irradiated minicells were examined for their ability to generate a mating signal at 43 degrees C in mating with HfrH dnaB(Ts) cells . The outer and inner membranes and heat-treated minicells all failed to stimulate incorporation of radioactive thymine; only ultraviolet-irradiated minicells retained the ability to generate a mating signal for the donor to initiate transfer replication.

J Bacteriol, 1978 Jan, 133(1), 433 - 6
ColE1 plasmid mutants affecting growth of an Escherichia coli recB recC sbcB mutant; Inselburg J; Three mutant derivatives of the plasmid ColE1 were found to reduce the formation of plasmidless cells in a recB recC sbcB cell population . An active plasmid role in the plasmid-host interaction is suggested.

J Bacteriol, 1978 Jan, 133(1), 43 - 52
Conjugal transfer system of plasmid RP4: analysis by transposon 7 insertion; Barth PT et al.; We have begun an analysis in Escherichia coli of the conjugal transfer functions of the broad-host-range plasmid RP4 . We have isolated 19 tra mutants of RP4, generated by insertion of transposon 7, and mapped their insertion sites by restriction endonuclease analysis . These sites fall into two separate regions on either side of the kanamycin resistance determinant . The transfer rates of the mutants range from 10% of that of RP4 to an undetectable level . Spot tests with the P-1 pilus-specific phages PRR1, Pf3, and PR4 and electron microscopic examination for pili have classified the mutants into several phenotypes consistent with their having normal, retracted, or no pili . Analysis of transient plasmid heterozygotes, created by P1 transduction, divided the tra mutants into a minimum of five complementation groups . Some of these groups contain more than one phenotypic class and may represent more than one gene because of the possible polar and deletion effects of Tn7 insertion.

J Bacteriol, 1978 Jan, 133(1), 409 - 10
Formation of N-carbamyl putrescine from citrulline in Escherichia coli; Akamatsu N et al.; Decarboxylation of citrulline by Escherichia coli enzymes was presented . The N-carbamyl putrescine produced showed the same properties as those of synthesized authentic samples in column chromatography, paper chromatography, and paper electrophoresis.

J Bacteriol, 1978 Jan, 133(1), 406 - 8
Preferential inhibitory action of sodium cholate on an Escherichia coli strain carrying a plasmid in an integrated state; Yoshida Y et al.; Sodium cholate was shown to be preferentially more active on Escherichia coli strains carrying an integrated plasmid, i.e., on Hfr strains, than on their parental strains with or without a plasmid in an autonomous state.

J Bacteriol, 1978 Jan, 133(1), 387 - 9
R plasmic Rtsl-mediated production of extracellular deoxyribonuclease in Escherichia coli; Matsumoto H et al.; Escherichia coli strains harboring Rtsl were found to excrete extracellular deoxyribonuclease . The DNase activity was greater in cells with pTW2, a mutant from Rtsl.

J Bacteriol, 1978 Jan, 133(1), 364 - 71
Identification of the structural gene for the hook subunit protein of Escherichia coli flagella; Komeda Y et al.; Previous studies showed that the structural gene for the flagellar hook subunit protein (molecular weight 42,000) was one of a group of flagellar genes located on the Escherichia coli genome near pyrC . Several lines of evidence indicate that the flaK gene is the structural gene for the hook subunit protein . Fla+ strains that were insensitive to chi infection could be isolated as revertants of an FlaK- amber mutant strain but from no other Fla- strain . The hook subunit proteins isolated from such chi-sensitive revertants of the FlaK- strain were shown to be antigenically and electrophoretically different from the hook protein isolated from the wild-type strain . Thus, reversion of a mutation in the flaK gene resulted in alteration of the structure of the hook protein . Furthermore, in programming experiments with hybrid lambda containing flagellar genes, lambdafla with flaK genetic activity programmed the synthesis of a 42,000-molecular weight protein, whereas lambdafla without flaK genetic activity did not.

J Bacteriol, 1978 Jan, 133(1), 33 - 42
F plasmid genes involved in the production of recombination-stimulating factor, control of sensitivity to some injurious agents, and chromosome replication in Escherichia coli K-12 HfrC; Chernin LS et al.; Three related F'arg+ plasmids isolated by Guyer and Clark were used to analyze some properties of strain MG751, a recipient derivative of an HfrC mutant (MG7) carrying a previously described pleiotropic mutation in the integrated F plasmid . Strains MG7 and MG751 both failed to produce recombination-stimulating factor, were sensitive to monofunctional alkylating agents and UV irradiation, and were temperature sensitive for growth and DNA synthesis . It was shown that these phenotypes are controlled by F plasmids genes (designated rsf, prt, and rep) that can be separated by deletion mutations occurring on the F plasmid.

J Bacteriol, 1978 Jan, 133(1), 329 - 35
Interaction between two major outer membrane proteins of Escherichia coli: the matrix protein and the lipoprotein; DeMartini M et al.; The affinity to the matrix protein, one of the major outer membrane proteins of Escherichia coli, for the peptidoglycan was examined of extracting the cell envelope complex at 55 degrees C and 2% sodium dodecyl sulfate containing different amounts of NaCl . It was found that the matrix protein was extracted from the peptidoglycan of a mutant strain (lpo) that lacks another major membrane protein, the lipoprotein, at a lower NaCl concentration than was the matrix protein of the wild-type cell (lpo+) . When the envelope fraction of the wild-type strain was treated with trypsin, which is known to cleave the bound-form lipoprotein from the peptidoglycan, the affinity of the matrix protein for the peptidoglycan decreased to the same level as that of the affinity of the matrix protein for the peptidoglycan of the mutant strain . It was further shown that the free-form lipoprotein was also retained in the matrix protein-peptidoglycan complex, although the extent of retention of the free form of the lipoprotein was less than that of the matrix protein . These results indicate that both the free and the bound forms of the lipoprotein are closely associated with the matrix protein and that the bound form of the lipoprotein plays and important role in the association between the matrix protein and the peptidoglycan.

J Bacteriol, 1978 Jan, 133(1), 306 - 19
Immunochemical analysis of inner and outer membranes of Escherichia coli by crossed immunoelectrophoresis; Smyth CJ et al.; Isolated membrane fractions of Escherichia coli K-12 yielded complex immunoprecipitate patterns when Triton X-100 and sodium dodecyl sulfate extracts were examined by crossed immunoelectrophoresis with antienvelope immunoglobulins . Twelve of the 46 antigens in the immunoprecipitate patterns of inner (plasma) membranes were identified by zymograms and/or by the use of specific antisera . The following enzyme activities were detected in immunoprecipitates: 6-phosphogluconate dehydrogenase (EC 1.1.1.43); adenosine triphosphatase (EC 3.6.1.3); glutamate dehydrogenase (EC 1.4.1.4), two separate components; malate dehydrogenase (EC 1.1.1.37); dihydroorotate dehydrogenase (EC 1.3.3.1); succinate dehydrogenase (EC 1.3.99.1); lactate dehydrogeanse (EC 1.1.1.27); reduced nicotinamide adenine dinucleotide dehydrogenase (EC 1.6.99.3); protease (EC 3.4.21.1); and glycerol 3-phosphate dehydrogenase (EC 1.1.99.5) . The corresponding immunoprecipitate pattern for isolated outer membranes consisted of at least 25 discrete antigens and differed strikingly from that obtained with inner membranes . Two major immunogens were identified as lipopolysaccharide and Braun lipoprotein . A protease-active immunoprecipitate was also detected in this fraction, but attempts to identify the Rosenbusch matrix protein in the crossed immunoelectrophoretic profile were unsuccessful.

J Bacteriol, 1978 Jan, 133(1), 279 - 86
Arrangement of protein I in Escherichia coli outer membrane: cross-linking study; Palva ET et al.; The arrangement of protein I in the outer membrane of Escherichia coli was investigated by cross-linking whole cells, isolated cell wall, protein-peptidoglycan complexes, and protein I released from peptidoglycan with NaCl . Both cleavable azide cross-linkers and imidoester reagents were used . The data presented suggest that protein I exists in the outer membrane as a trimer.

J Bacteriol, 1978 Jan, 133(1), 270 - 8
Uptake of extracellular biotin by Escherichia coli biotin prototrophs; Cicmanec JF et al.; Uptake of exogenous biotin by two Escherichia coli biotin prototroph strains, K-12 and Crookes, appeared to involve incorporation at a fixed number of binding sites located at the cell membrane . Incorporation was characterized as a binding process specific for biotin, not requiring energy, and stimulated by acidic pH . Constant saturation quantities of exogenous biotin were incorporated by these cells, and the amounts, which were titrated, depended on whether the cells were resting or dividing . Resting cells incorporated exogenous biotin amounting to 2% of their total intracellular biotin content . Fifty percent of the exogenous biotin was incorporated into their free biotin fraction, and 50% was incorporated into their bound biotin fraction . On the other hand, dividing cells incorporated exogenous biotin into all of their intracellular sites, 88% going into the intracellular-bound biotin fraction, and 12% going into the free biotin fraction . Calculations suggested that each cell contained approximately 3,000 binding sites for biotin . It was postulated that biotin incorporation sites might have been components of acetyl coenzyme A carboxylase located at or near the membrane.

J Bacteriol, 1978 Jan, 133(1), 178 - 84
Regulatory properties of araC(c) mutants in the L-arabinose operon of escherichia coliB/r; MacInnes KR et al.; Merodiploids containing a high-constitutive and a low-constitutive araC(c) allele were assayed for constitutive expression of the ara operon . Low-constitutive araC(c) alleles either were unable to repress the constitutive rate of ara operon expression exhibited by by high-constitutive araC(c) alleles or achieved a partial repression of the high-constitutive rate of operon expression . Either mutation to a low-constitutive araC(c) mutant resulted in a partial or complete loss of repressor function, or subunit mixing between the two araC(c) mutant proteins resulted in a partial or complete dominance of the high-constitutive araC(c) allele . Five of the six araC(c) alleles tested allowed a partial induction of the ara operon in cya crp background . In general, a higher level of ara operon induction was achieved in the cya crp background by high araC(c) alleles than by low araC(c) alleles . Furthermore, several araC(c) mutants exhibited decreased sensitivity to catabolite repression, particularly in the presence of inducer . The results suggest a model in which certain araC(c) gene products can achieve ara operon induction in the presence of either arabinose (inducer) or catabolite activator protein-cyclic adenosine monophosphate, whereas the wild-type araC gene product requires the presence of both of these factors for operon expression.

Chemotherapy, 1978, 24(1), 24 - 8
Binding of chloramphenicol and its acetylated derivatives to Escherichia coli ribosomal subunits; Piffaretti JC et al.; Chloramphenicol-acetylated derivatives (1-monoacetoxy-; 3-monoacetoxy-; 1,3-diacetoxy-chloramphenicol), produced by a wild type Escherichia coli strain carrying an R factor, have been extracted and purified . None of the acetylated derivatives has been found to bind to E . coli ribosomal subunits.

Scand J Immunol, 1978, 8(4), 323 - 31
A chemical approach to the mechanism of B-lymphocyte activation . II . The pure presentation of haptens does not inactivate B lymphocytes; Vidal-Gomez J; Dinitrophenyl (DNP)-lysine-polymethylmethacrylate and DNP-cellulose conjugates do not irreversibly inactivate anti-DNP antigen-sensitive cells, regardless of the dose (up to 10 mg) or persistence of the stimulation (up to 2 weeks) . Since these conjugates constitute pure hapten presentations, it is concluded that the pure hapten presentation to B lymphocyte does not irreversibly inactivate them . When murine spleen cells are cultured with Escherichia coli lipopolysaccharide (LPS) and (non-immunogenic) DNP-lysine-polymethylmethacrylate or (non-immunogenic) DNP-cellulose conjugates, an anti-DNP immune response occurs . However, replacement of DNP-lysine-polymethylmethacrylate with polymethylmethacrylate, or DNP-cellulose with cellulose, also results in a similar anti-DNP response . It is consequently concluded that the anti-DNP responses are entirely elicited by LPS, the hapten Dnp being inoperative . The anti-DNP response elicited by DNP-Ficoll is, upon exhaustive testing, carrier-dependent . This implies that the mechanism of DNP-Ficoll immunogenicity is not two cooperative signals passed on to B lymphocytes via the hapten DNP . These results argue against any two-signal model of B-lymphocyte activation.

Neoplasma, 1978, 25(1), 133 - 9
L-asparaginase in treatment of acute leukemia in children; Misikova Z et al.; L-asparaginase from Escherichia coli--Crasnitin was used in 14 children with acute leukemia unresponsive to conventional treatment: 11 acute lymphoblastic leukemias, 1 acute myeloblastic leukemia, 2 other forms of leukemia . The remission induction was obtained in 70% of applications . Median of remission duration was 90 days . Serious side effects were observed . The validity of L-asparaginase in therapy of advanced childhood ALL is stressed.

Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 153 - 7
Structure of nascent replicative form DNA of coliphage M13; Dasgupta S et al.; Nascent replicative form type II (RFII) DNA of coliphage M13 synthesized in an Escherichia coli mutant deficient in the 5' leads to 3' exonuclease associated uith DNA polymerase I contains ribonucleotides that are retained in the covalently closed RFI DNA sealed in vitro by the joint action of T5 phage DNA polymerase and T4 phage DNA ligase . These RFI molecules are labile to alkali and RNase H, unlike the RFI produced either in vivo or from RFII with E . coli DNA polymerase I and E . coli DNA ligase . The ribonucleotides are located at one site and predominantly in one strand of the nascent RF DNA . Furthermore, these molecules contain multiple small gaps, randomly located, and one large gap in the intracistronic region.

Adv Shock Res, 1978, 1, 125 - 47
Zymosan-induced resistance to endotoxin and hemorrhagic shock; Joyce LD et al.; Improved surgical techniques and judicial use of available antibiotics have reduced the number of postoperative complications over the past decade . However, septic and hemorrhagic shock occur all too frequently, and each carries with it an appreciable morbidity and mortality . Endotoxins and hemorrhage are both known to suppress the phagocytic activity of the reticuloendothelial system (RES) . On the other hand, zymosan, a yeast (Saccharomyces cerevisiae) cell wall preparation administered intravenously, results in temporary RES hyperplasia and increased phagocytic activity . Dogs were pretreated with zymosan to determine the degree of RES stimulation and protection against endotoxin and hemorrhagic shock attainable . Twenty-five dogs received intravenous zymosan (10 mg/kg) on days 1, 2, and 3 . Another 24 dogs served as controls . On day four, one-half the animals in each group received E coli endotoxin (1.5 mg/kg) intravenously . The other animals underwent two hours of hemorrhagic shock at a mean blood pressure of 40 mm Hg . Seventy-two hour survival was as follows: Endotoxin treated, 66.7% (8/12); endotoxin control, 27% (3/11); hemorrhagic treated, 53.3% (8/15); and hemorrhagic control, 28.6% (4/14) . Hemodynamic, metabolic, and lysosomal enzyme parameters were evaluated . No zymosan toxicity was observed . These findings suggest that an RES stimulant such as zymosan could be incorporated as preoperative adjunctive therapy to induce resistance to these shock syndromes in the elective surgical patient.

Microbios, 1978, 23(93-94), 175 - 92
Fructose-1,6-diphosphatase: a cellular site of hyperbaric oxygen toxicity; Brown OR et al.; The growth-inhibitory effect of 4.2 atm of hyperbaric oxygen for Escherichia coli was strongly influenced by available nutrients . A pattern of protection was achieved with various carbohydrate intermediates which was consistent with oxygen-induced poisoning of fructose-1,6-diphosphatase and of enzymes required in the pentose shunt and for converting galactose into glucose . Two of these sites have not been investigated further, but direct evidence was obtained that purified fructose-1,6-diphosphatase was inactivated in vitro by superoxide anion, but not by molecular oxygen at hyperbaric pressure (4.2 atm) . Poisioning of fructose-1,6-diphosphatase by metabolically generated oxygen radicals, such as superoxide ion, would have deleterious effects for E . coli in media where synthesis of glucose by reverse glycolysis is required, and presumably for cells of higher organisms, including man.

Arzneimittelforschung, 1978, 28(12), 2246 - 51
Further studies on the antipyretic action of polymyxin B in pyrogen-induced fever; van Miert AS et al.; A study of the antipyretic effect of polymyxin B was undertaken to determine how this agent reduces fever in rabbits . It involved the effects of the drug: (1) on fever induced by exogenous pyrogenes (E . coli lipopolysaccharide, synthetic double-stranded ribonucleic acid, sodium nucleinate from yeast) and leucocytic pyrogen, (2) on the release of endogenous pyrogen in vivo and in vitro, and (3) on leucocytic and exogenous pyrogens in vitro . The results indicate that polymyxin B produces an antipyretic effect in endotoxin-induced fever primarily by an interaction of this cationic macromolecule with the anionic endotoxin molecule . Further it is likely that polymyxin B inhibits endogenous pyrogen synthesis and/or release from polymorphonuclear leucocytes.

Acta Biol Med Ger, 1978, 37(9), 1363 - 76
Preparation and properties of a Met-tRNAf binding factor from rat liver and rat hepatoma; Bommer UA et al.; A Met-tRNAf binding factor (IF-2) from the microsomal fraction of rat liver and rat hepatoma ascites cells was partially purified by ammonium sulphate fractionation, DEAE-cellulose and phosphocellulose chromatography . The factor binds {3H}Met-tRNAf only in the presence of either GTP or GMPPCP . Maximal binding takes place at 37 degrees C and in the absence of Mg++ . The factor is specific for Met-tRNAf and does not bind Phe-tRNA from rat liver or from E . coli . The ternary complex {Met-tRNAf . IF-2 . GTP1 binds to 40 S ribosomal subunits from rat liver in the absence of mRNA or poly(A, G, U) without GTP hydrolysis . GDP as well as aurintricarboxylic acid inhibit the ternary complex formation . Both factors are rapidly inactivated by N-ethylmaleimide treatment and by preincubation at 45 degrees C . Heat inactivation is partially prevented by GTP and GDP . With regard to the functional properties there are no significant differences between IF-2 from normal liver and hepatoma cells . On the other hand heat denaturation compared to the rat liver factor, which may be due to differences in contaminating proteins.

Prep Biochem, 1978, 8(6), 479 - 502
Purification of acetate kinase by affinity chromatography; Swartz JR et al.; A one-step procedure using affinity chromatography has been shown to purify to apparent homogeneity acetate kinase from a commercially available preparation and to partially purify the enzyme from a crude, cell-free extract . Since the gel's capacity for enzyme adsorption is controlled by the thermodynamics of ligand-enzyme interaction, maximization of the adsorption isotherm was attempted . Enzyme adsorption decreased logarithmically with increasing ionic strength but increased with increasing concentration of MgCl2 . These competing effects caused the net adsorption of enzyme to increase to a maximum and then to decrease as the MgCl2 concentration was raised . The results allow a significant improvement in affinity column performance and have important implications for scale-up procedures.

Prep Biochem, 1978, 8(6), 471 - 8
A method of the rapid preparation of adenosine 5'-gamma-{32P} triphosphate by chemical synthesis; Koziolkiewicz W et al.; A new chemical method for the synthesis of adenosine 5'-gamma-{32P} triphosphate has been developed based on the reaction of adenosine 5'-diphosphate with ethyl chloroformate . The resulting active mixed anhydride was able to react with {32P}-triethylammonium orthophosphate to give gamma-{32P}ATP.

J Supramol Struct, 1978, 9(2), 219 - 30
The Escherichia coli adenylate cyclase complex: activation by phosphoenolpyruvate; Peterkofsky A et al.; A model for the regulation of the activity of Escherichia coli adenylate cyclase is presented . It is proposed that Enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) interacts in a regulatory sense with the catalytic unit of adenylate cyclase . The phosphoenolpyruvate (PEP)-dependent phosphorylation of Enzyme I is assumed to be associated with a high activity state of adenylate cyclase . The pyruvate or sugar-dependent dephosphorylation of Enzyme I is correlated with a low activity state of adenylate cyclase . Evidence in support of the proposed model involves the observation that Enzyme I mutants have low cAMP levels and that PEP increases cellular cAMP levels and, under certain conditions, activates adenylate cyclase, Kinetic studies indicate that various ligands have opposing effects on adenylate cyclase . While PEP activates the enzyme, either glucose or pyruvate inhibit it . The unique relationships of PEP and Enzyme I to adenylate cyclase activity are discussed.

Microbiol Immunol, 1978, 22(9), 557 - 64
Modification of immune response in nude mice infected with mouse hepatitis virus; Tamura T et al.; In nude mice experimentally infected with mouse hepatitis virus (MHV), the numbers of early and later plaque forming cells (PFC) to sheep red blood cells (SRBC) generated in the spleen were 7 to 20 times and 2 to 163 times, respectively, greater than those in non-infected nude mice, when SRBC were given at day 0 to day 21 postinfection . Splenic theta-positive lymphocytes in infected nude mice were shown to increase only at day 10 or more postinfection . PFC response to bacterial lipopolysaccharide, a T cell-independent antigen, was not modified in MHV-infected nude mice.

Biochimie, 1978, 60(8), 755 - 65
{Quaternary structure and proteolysis of the polynucleotide phosphorylase from C . perfringens}; Guissani A; This report describes structural studies on purified polynucleotide phosphorylase from C . perfringens . A method is described for the purification of the enzyme which yields a product equivalent in activity to the native polynucleotide phosphorylase from E . coli . These studies revealed a molecular heterogeneity arising from successive stages of proteolysis, to which this enzyme is especially sensitive; unusally, the enzyme is obtained as a mixture of variable proportions of the native and proteolysed forms . We found in all cases a trimeric basic structure composed of the native (alpha) or proteolysed (lapha) or proteolysed (alpha', alpha") catalytic sub-units, However, the enzyme is rather easily dissociated into its sub-units, a phenomenon which seems to accompany proteolysis (Table) . Under the action of either endogenous proteases or trypsin, two enzymatic forms are obtained: their quaternary structures seem analogous, but they differ in their catalytic properties from each other and from the initial enzyme . With some care at each step of purification, the polynucleotide phosphorylase of E . coli can be obtained exclusively in its native form . The greater susceptibility to proteolysis of the enzyme from C . perfrigens and the relationship between such degradation and quaternary structure seem to be at the origin of the peculiar behavior of this polynucleotide phosphorylase.

Adv Exp Med Biol, 1978, 110, 175 - 91
Results of a five-year study of the curative effect of double stranded ribonucleic acid in viral dermatoses and eye diseases; Borecky L et al.; Double stranded RNA obtained from non-permissive E . coli cells infected with f2-phage was tested in 5 hospitals in viral dermtoses such as herpes simplex recidivans, herpes zoster, male genikeratonconjunctivitis herpetica and conjunctivitis lignosa . The results of clinical tests indicate that the preparation of phage double stranded RNA applied topically is harmless for man and has, in the majority of cases, a beneficial effect in the disease . This conclusion was based on the judgment of physicians, opinion of patients expressed in a questionnaire, and, results of a double-blind experiment.

J Hyg Epidemiol Microbiol Immunol, 1978, 22(1), 83 - 9
A comparative study of functional activity and cytochemical characteristics of human and rabbit microphages; Venglinskaya EA et al.; Substantial differences were found in the cytochemical indices of human and rabbit microphages . Regular changes in the enzymic activity and the levels of some biopolymers were observed in the microphages in the process of phagocytosis . The extent and (in some cases) tendency of these changes in human and rabbit microphages are not the same . Cytochemical indices provide significant information on the functional activity of the microphage system within one species . At the interspecies level, such information proves to be inadequate for the characteristic of the phagocytic ability of microphages unless humoral non-specific means of protection are taken into account.

Zentralbl Bakteriol Naturwiss, 1978, 133(3), 245 - 9
Cyclic-AMP content in Escherichia coli B/b as affected by N1-(delta 2-isopentyl)adenine; Coppola S et al.; N6-(delta 2-isopentenyl)adenine, like other cytokinins, does not detectably modify Escherichia coli growth, but strongly affects cellular levels of cAMP . A substantial delay of the highest level of intracellular cAMP, a reduction to about one half of such maximum level, and a slight increase of cAMP secreted into the medium are reported.

Annu Rev Biochem, 1978, 47, 449 - 79
Proteins that affect DNA conformation; Champoux JJ; In eucaryotic cells virtually all of the DNA is complex with proteins to form a unit fiber approximately 100 A in diameter . Chromatin is formed by the higher order coiling of the unit fiber . In procaryotic cells, as exemplified by E . coli, the actual structure of the chromosome is less clear (218), but the discovery of the DNA gyrase raises the possibility that the DNA helix in the cell is maintained in an underwound state . It may be important to consider these structural features of DNA in future biochemical studies on replication, transcription, and recombination . The recent discoveries of the DNA swivelases, the DNA gyrase, and the DNA unwinding enzymes considerably increase our knowledge of DNA biochemistry . As more is learned about these enzymes and their interaction with DNA, the prospects for understanding the details of DNA transcription, DNA recombination, and particularly DNA replication appear to be good.

Trans R Soc Trop Med Hyg, 1978, 72(2), 164 - 6
Electrophoretic isoenzyme patterns of Entamoeba histolytica and Entamoeba coli; Sargeaunt PG et al.; Cultures of 14 stocks of Entamoeba histolytica and one only of Entamoeba coli were compared by electrophoretic patterns of three enzymes: glucose-phosphate isomerase, phosphoglucomutase and L-malate: NADP+ oxidoreductase (oxaloacetate-decarboxylating) . Easily distinguished patterns divided E . histolytica into three groups, whilst a distinctly different pattern for E . coli was also seen.

Mikrobiologiia, 1978 Jan-Feb, 47(1), 72 - 7
{Fatty acid makeup of Escherichia coli cells with repressed and derepressed phosphohydrolase biosynthesis}; Nesmeianova MA et al.; Fatty acid composition of the cells of Escherchia coli wild strains K-10, and K-12 and the mutants of the regulatory genes for alkaline phosphatase was studied in conditions of repression and derepression of biosynthesis of phosphohydrolases . Derepression of phosphohydrolases was not accompanied with specific changes in fatty acid composition of the cells . An increase in the content of cyclopropanic acid in conditions of phosphorus deficiency and a decrease in the level of unsaturated fatty acids are related to deceleration of growth of the cells in these conditions.

Proc Natl Acad Sci U S A, 1978 Jan, 75(1), 238 - 42
DNA intermediates at the Escherichia coli replication fork: effect of dUTP; Olivera BM; We have directly tested the hypothesis that elevated levels of dUTP cause the formation of small DNA fragments at the replication fork of Escherichia coli . Addition of increasing levels of dUTP to lysates on cellophane discs results in an increasing number of strand scissions in the newly replicated DNA . Lysates of strains defective in dUTPase produce many more scissions at the same level of dUTP . The size distribution of Okazaki pieces obtained in vivo can be reconstituted in vitro on cellophane discs if appropriate levels of dUTP are present . Although uracil excision leads to the apparent production of Okazaki pieces from both daughter strands, DNA synthesis is actually asymmetric under these conditions . De novo chain initiation events occur on only one strand . It is suggested that asymmetry of synthesis in vivo may be masked by uracil excision and other postreplication processing mechanisms.

Genetika, 1978, 14(1), 103 - 10
{Effect of mutations for adenylate cyclase (cya) and the cyclic adenosine monophosphate receptor protein (cgp) on the gene expression of nucleoside catabolism in Escherichia coli}; Mironov AS et al.; The effect of cya and crp mutations on the expression of the activity of nucleoside catabolizing genes has been studied in Escherichia coli . It is found that cya and crp mutants lose their ability to grow on nucleosides as carbon sources in spite of the preservation of the basal levels of nucleoside catabolizing enzymes, found in cell-free extracts of cya and crp mutants . It is shown that cya and crp mutations completely release the influence of the regulatory gene cytR on the activity of uridine phosphorylase (udp gene) and thymidine phosphorylase (tpp gene) . On this ground it is assumed that the cytR gene product acts at the level of promotors of the corresponding structural genes, causing their insensitivity to the positive action of cAMP--CRP complex . The same data concerning the effect of cya and crp mutations on cytR regulation have been reported {8}, but these authors favoured the hypothesis that the cytR gene product is a repressor protein, which binds to the specific operator.

J Virol, 1978 Jan, 25(1), 305 - 11
Effect of chemical modification of supercoiled simian virus 40 DNA on the rate of in vitro transcription; Hale P et al.; Superhelical simian virus 40 FI DNA could be modified with the single-strand-specific reagent N-cyclohexyl-N'-beta-(4-methylmorpholinium)ethylcarbodiimide (CMC) . A limited reaction, of less than 2% of the base pairs, resulted in almost total inhibition of in vitro transcription by DNA-dependent RNA polymerase from Escherichia coli . This effect was shown to be due to DNA modification and not to inhibition of polymerase activity by the reagent . Inhibition of enzyme activity occurred if the contaminating reagent was not absorbed with another protein before polymerase addition . No inhibition was observed when DNA and polymerase were incubated together to allow the formation of pre-initiation complexes before CMC was added . Studies of template saturation with polymerase showed that the inhibition of transcription by DNA modification was due to a loss of binding ability of the enzyme to the reacted, supercoiled DNA when reaction times of less than 2 h were used.

J Virol, 1978 Jan, 25(1), 298 - 304
Binding and transcription of simian virus 40 DNA by DNA-dependent RNA polymerase from Escherichia coli; Hale P et al.; Supercoiled simian virus 40 was transcribed more efficiently than nonsupercoiled DNA . The effect was increased from two- to fivefold by the addition of rifampin with triphosphates . The number and locations of polymerase binding sites with respect to Hin II-III restriction fragments were determined . The total number of binding sites was nine, as determined by UV difference spectroscopy . The locations of these binding sites were on the A, B, D, E, F, and G fragments, as determined by gel electrophoresis . The number of sites was the same for both supercoiled and relaxed or Hin II-III-digested DNA, and the point of saturation of supercoiled DNA by polymerase remained the same with increasing concentrations of rifampin from 0 to 8 microgram/ml.

J Virol, 1978 Jan, 25(1), 274 - 84
Endoribonuclease activity associated with animal RNA viruses; Kolakofsky D et al.; A specific endoribonucleolytic activity was detected when detergent-lysed vesicular stomatitis of Sendai virus was incubated with the precursor to Escherichia coli tRNA Tyr . The cleavage products produced and the characteristics of the reaction were similar to those previously reported for human KB cell RNase NU . Like RNase NU, the virus-associated reaction generates 5'-hydroxyl and 3'-phosphate groups at the cleavage sites . At protein concentrations similar to those used to test vesicular stomatitis and Sendai viruses, virions of Sindbis virus and poliovirus also exhibited endoribonucleolytic activity, but reovirus, simian virus 40, and minute virus of mice did not . This endoribonuclease may be of physiological relevance to some of the viruses we tested.

J Bacteriol, 1978 Jan, 133(1), 196 - 202
Mapping of the mecillinam-resistant, round morphological mutants of Escherichia coli; Iwaya M et al.; Genes responsible for round morphology in mecillinam-resistant, round morphological mutants of Escherichia coli have been mapped . Three mutants, called rodX, mapped at around 14 min, and two, called rodY, mapped at around 70 min by P1 transduction . These are either the same or very close to the loci reported, respectively, for the rodA (H . Matsuzawa, K . Hayakawa, T . Sato, and K . Imahori, J . Bacteriol . 115:436-442, 1973) and envB genes (B . Westling-Haggstrom and S . Normark, J . Bacteriol . 123:75-82, 1975) . This suggests that mecillinam can be used very efficiently to select for found morphological mutants of rodA and envB after nitrosoguanidine treatment.

Fed Proc, 1978 Jan, 37(1), 9 - 14
From deoxynucleotides to DNA synthesis; Reichard P; The deoxyribonucleotides required for DNA synthesis are provided by reduction of ribonucleotides . Our studies aim at an understanding of the interplay between the processes involved in the production of deoxyribonucleotides and in their consumption . The enzyme system reducing ribonucleotides has been characterized in some detail, and its regulatory aspects were investigated with pure enzymes . Knowledge gained in this way made it possible to interfere specifically with the activity of ribonucleotide reductase in intact cells and to study effects on DNA synthesis . In this connection, the replication of polyoma DNA was used as a model that allowed dissection of DNA synthesis into different steps involved in the initiation and elongation processes.

Microbios, 1978, 23(92), 99 - 113
The influences of a lambda prophage on the growth rate of Escherichia coli; Dykhuizen D et al.; A lambda prophage increases the competitive ability of E . coli K12 in a glucose-limited chemostat . This phenomenon does not involve the lambdarex gene . Expression of the lambdarex gene conditionally decreases fitness in two ways: (1) it causes malT- but not malT+ lysogens to be at a selective disadvantage in competition with non-lysogens . (2) During adaptation to slow, glucose-limited chemostat growth from rapid, glucose-excess flask growth, expression of the lambdarex gene transiently decreases the growth rate when compared to the non-lysogen.

Drug Chem Toxicol, 1978, 1(2), 103 - 35
Genetic screening of compounds used in drug abuse treatment . I . Naltrexone hydrochloride; Brusick D et al.; Several compounds used clinically in drug abuse therapy were evaluated for genetic activity in a series of in vitro assays . This initial report describes the results for one of these compounds, Naltrexone . Nalrexone is a relatively nontoxic drug antagonist related to Naloxone which appears to be effective in diminishing the euphoria and dependence upon heroin in clinical studies . With the exception of weak nonspecific DNA damage observed in an E . coli DNA repair test and possibly with WI-38 cells as well, Naltrexone did not demonstrate significant potential for the induction of gene mutations or chromosomal aberrations under the conditions of this evaluation.

Scand J Immunol, 1978, 8(3), 257 - 62
Polymorphonuclear leucocyte function during pregnancy; Bjorksten B et al.; Polymorphonuclear leucocyte (PMN) function was studied in pregnant women and related to the serum concentration of pregnancy zone protein (PZP) and to mixed lymphocyte culture (MLC) reactivity . Neutrophil chemotaxis was depressed in pregnant women . Pregnancy serum inhibited the MLC-reaction . The serum levels of PZP were inversely related to chemotactic responsiveness (P less than 0.05) and depression of MLC reactivity (P less than 0.01) . The capacity to reduce nitroblue tetrazolium was depressed in PMNs from pregnant women, and pregnancy serum inhibited phagocytosis of Escherichia coli by control PMNs . Neutrophils from pregnant women showed increased chemiluminescence during phagocytosis of zymosan . The results may be explained by depression of ingestion by pregnancy serum and increased oxidative metabolism in PMNs from pregnant women.

J Biochem (Tokyo), 1978 Jan, 83(1), 137 - 40
Identification of an outer membrane protein responsible for the binding of the Fe-enterochelin complex to Escherichia coli cells; Ichihara S et al.; Escherichia coli incorporates iron as a complex with enterochelin . By using mutants which lack one or the other, or both, of the outer membrane proteins, O-2b and O-3, we have shown that protein O-2b (feuB protein) is responsible for the primary binding of the iron-enterochelin complex to the outer membrane in the process of iron transport.

Folia Microbiol (Praha), 1978, 23(1), 30 - 6
Metabolic and genetic control of isoenzyme spectrum of alkaline phosphatase in Escherichia coli; Nesmeyanova MA et al.; Three proteins possessing alkaline phosphatase activity were detected in a fraction of periplasmic material of Escherichia coli K-10 and its mutants with constitutive synthesis of alkaline phosphatase . They also showed acid phosphatase, pyrophosphatase and ATPase activities . Through the use of phosphatase-negative mutants it was shown that these proteins were the products of a single structural gene and therefore represented alkaline phosphatase isozymes . The numbers of enzyme isoforms and possibly the spectrum of their phosphohydrolase activities were controlled by exogenous orthophosphate and depended on the integrity of regulator genes for alkaline phosphatase.

J Bacteriol, 1978 Jan, 133(1), 287 - 92
Inhibition, by a protease inhibitor, of the solubilization of the F1-portion of the Mg2+-stimulated adenosine triphosphatase of Escherichia coli; Cox GB et al.; The effects of two protease inhibitors on the solubilization of the membrane-bound Mg2+-adenosine triphosphatase (Mg-ATPase) of Escherichia coli were investigated . p-Aminobenzamidine prevented the solubilization of the Mg-ATPase during treatment of membranes with low-ionic-strength buffers containing ethylenediaminetetraacetic acid . p-Aminobenzamidine did not prevent subsequent solubilization of the Mg-ATPase by treatment of the membranes with chloroform . This method of solubilization yielded a preparation of similar apparent molecular weight but with a 10-fold-increased specific activity as compared with the Mg-ATPase solubilized by washing with low-ionic-strength buffer . However, in contrast to the latter preparation, the chloroform-solubilized Mg-ATPase did not reconstitute ATP-dependent energization of stripped membranes, which were prepared by low-ionic-strength washing in the absence of p-aminobenzamidine . Another protease inhibitor, epsilon-amino-n-caproic acid, did not effect the solubilization of the Mg-ATPase, but did inhibit the loss of activity occurring during concentration, by ultrafiltration, of the Mg-ATPase solublized by the low-ionic-strength treatment.

J Bacteriol, 1978 Jan, 133(1), 108 - 13
Energy transduction in Escherichia coli: physiological and biochemical effects of mutation in the uncB locus; Hasan SM et al.; The transduction of energy through biological membranes was investigated in Escherichia coli strains defective in the ATP synthetase complex . Everted vesicles prepared from strains containing an uncA or uncB mutation were compared with those of the parental strain for their ability to couple energy derived from the oxidation of substrates by the electron transport chain or from the hydrolysis of ATP by the Mg2+-adenosine triphosphatase, as measured by the energy-dependent quenching of quinacrine fluorescence or the active transport of 45Ca2+ . Removal of the Mg2+-adenosine triphosphatase from membranes derived from the parental or an uncA strain caused a loss of energy-linked functions and a concomitant increase in the permeability of the membrane for protons . Proton impermeability was restored by treatment with N,N'-dicyclohexylcarbodiimide . When membranes of the uncB strain were treated in a similar manner, there was no loss of respiratory-driven functions, nor was there a change in proton permeability . These observations suggest that the uncB mutation specifically results in alteration of an intrinsic membrane protein channel necessary for the generation of utilzation of the electrochemical gradient of protons by that complex . Loss of the function of the proton channel is believed to prevent the transduction of energy through the ATP synthetase complex.

Z Exp Chir, 1978, 11(5), 317 - 21
A model of experimental endotoxin shock in monkeys and its therapeutic control; Hajek M et al.; The course and therapy of endotoxin shock were studied in 34 monkeys Macaca mulatta . E . coli endotoxin was infused intravenously to conscious animals . The individual responses to a dose of 3 mg . kg-1 exhibited a considerable variability . A part of shocked animals were successfully rescued by a combined infusion of dopamine, hydrocortisone, and dextran; untreated animals died of endotoxin shock . Morphological changes in their parenchymatous organs were little marked in the acute experiment.

Zentralbl Bakteriol Naturwiss, 1978, 133(4), 320 - 40
Mechanism of action of bilharcid and tartar-emetic; Khafagy EZ et al.; An investigation on the mechanism of action of bilharcid and tartar-emetic produced the following results . Deoxyribonucleic acid (DNA) synthesis by cell of E . coli B from either the maximum stationary phase or the exponential phase are inhibited by 3.62 mM of bilharcid or 16.81 mM of tartar-emetic immediately upon addition of the inhibitor . These drugs cause a downshift of the Tm of native DNA . They displace MG from the DNA-MG complex . They increase the specific viscosity of DNA solution . Also the synthesis of constitutive enzyme (alkaline phosphatase) was stopped, as was the induction of the synthesis of new enzyme (beta-galactosidase) . Bilharcid and tartar-emetic act primarily on cell membrane and cause the release of 260 mM absorbing substances from E . coli B . Moreover, they lyse not only protoplasts of B . subtilis, but also spheroplasts of E . coli B.

Z Allg Mikrobiol, 1978, 18(6), 399 - 407
Evidence for repair of ultraviolet-induced damage in Cystobacter species (Myxobacterales); Grimm K; Cystobacter species strain CK 1 does not grow with more than 0.2 microgram/ml acriflavine . Spontaneous two-step mutants growing with 2 microgram acriflavine per ml have been selected . One mutant (strain CK3) was used to investigate the effect of repair inhibitors . Both strains exhibit pronounced shoulders in their UV dose curves of inactivation . Acriflavine (AF), coumarin (CU), and caffeine (CA) when incorporated in the post-irradiation plating medium decreased survival of irradiated cells . Post-treatment with 2 microgram acriflavine/ml abolished the shoulder of the curve . Caffeine (1600 microgram/ml) and coumarin (350 microgram/ml) reduced it only to about 40% . It is concluded that probably two repair mechanisms are present . Pre-treatment of the cells with 2 microgram acriflavine/ml for two hours before UV-irradiation resulted in a constant dose enhancement factor of 1.9 . The protective effect is increased with the time of treatment with acriflavine . This may indicate that pyrimidine dimers are responsible for UV-inactivation.

Toxicol Eur Res, 1978, 1(5), 283 - 8
{Action of a dithiocarbamate (zinebe) on the liver biosynthesis of RNA and proteins in the rat (author's transl)}; Moule Y; Zineb (zinc ethylene bisdithiocarbamate) inhibits the transcriptional activity of an in vitro system functioning with either RNA polymerases of isolated rat liver nuclei or purified E . coli RNA polymerase . Zineb also inhibits the in vitro aminoacid incorporation mediated by a polysomal standard system, by interacting with some pH 5 enzyme components(s) . When rats fed a balanced semi-synthetic diet containing zineb (5 200 mg/kg) for ten weeks, one may observe a decrease in the RNA and protein syntheses in liver . The consequences of the ingestion of small but repeated doses of zineb are discussed.

Arch Immunol Ther Exp (Warsz), 1978, 26(1-6), 675 - 9
The effect of some unspecific stimuli on defence mechanisms in weaned pigs; Wlodarczak C; The studies were performed to find out whether a prophylactic use of unspecific stimuli affects appreciably the selected biologic indices in weaned pigs . The variables used in the experiment were found to exert a favourable effect on the state of health and growth of pigs but they had no essential influence on the level of immunoglobulins and increase in the titre of antibodies against E . coli (0141, 0149), isolated from pigs kept in the same pigsty.

Ann Rech Vet, 1978, 9(3), 427 - 32
Detecting enteropathogenic strains of Escherichia coli of porcine origin . 2 . Relationship between O and K antigens and the production of enterotoxin in strains isolated from the piglet after weaning; Renault L et al.; The production of enterotoxin by biological tests (Yl adrenal cells and the suckling mouse) has been examined in 96 strains of Escherichia coli, isolated from sick piglets after weaning . There is a good correlation between the presence of the capsular antigen K88 and that of the thermolabile fraction (LT) of the enterotoxin (69.2 per cent of the enteropathogenic strains studied) . However, the presence of the thermostable fraction (ST) of the enterotoxin of strains which, according to their serological grouping, possess in theory the two fractions LT + ST or only the ST fraction is only confirmed in a small number of strains (16 per cent) by the biological test.

Acta Microbiol Pol, 1978, 27(4), 321 - 9
Replication of plasmid R6K in DNA polymerase deficient mutants of Escherichia coli; Wlodarczyk M et al.; The plasmid R6K has been introduced into a number of Escherichia coli polymerase deficient (pol) mutants . In polCts mutants transferred to the nonpermissive temperature to inactivate polymerase III, R6K replicates but the replication products have a density in dye-CsCl gradients intermediate between supercoiled and linear forms . This aberrant replication requires normal cellular levels of polymerase I since it does not occur in polA polCts mutants . Normal R6K replication and maintenance occur in a polA polB polC+ host, however, we cannot tell from our experiments wheather polymerase I or III replicates R6K in polA+ polC+ host . Polymerase II, the polB gene product, has no detectable role in R6K replication.

Z Allg Mikrobiol, 1978, 18(8), 567 - 73
Photochemistry and photobiology of 5-azacytidine: effect of repair on photostabilization of Escherichia coli; Hradecna Z et al.; The photochemical stability of the anomalous nucleic acid base 5-azacytidine (z5Cyd) on irradiation at 254 nm is by about one order of magnitude less than that of cytidine (Cyd) . Contrary to the photochemical behaviour, incorporation of z5Cyd into the nucleic acids of E . coli strains SR 20 (uvr+ rec+), SR 74 (uvr+ rec-) and SR 22 (uvr- rec+) produced a higher resistance to UV light . Only the SR 73 (uvr- rec-) strain was shown to have an increased UV sensitivity . This latter finding is in accord with the photochemical properties of z5Cyd . The results led to the conclusion that excision and recombination repair processes contribute to the observable protective effect . The fact that inhibition of excission repair by caffeine or proflavine of the mutant uvr+ rec- changes protection into sensitization supports this idea.

Infection, 1978, 6(6), 248 - 51
Granulocytic function after administration of pepsin treated human gammaglobulin; Lindquist L et al.; Pepsin-treated human gammaglobulin, 150 mg/kg body weight, was administered intravenously to 14 healthy volunteers . Before and after the infusion the nitroblue tetrazolium (NBT)-reduction of granulocytes was studied in all and the bactericidial capacity in 12 subjects . An increase of NBT reduction (p less than 0.05) and of bacterial capacity (p less than 0.01) of granulocytes was found after the infusion . The effects may be due to an opsonising action of F (ab')2 components.

Nucleic Acids Res, 1978 Jan, 5(1), 285 - 95
Enzymatic synthesis of DNA complementary to mitochondrial mRNA via reverse transcription; Frolova L et al.; The poly(A)-containing mitochondrial mRNAs of rat liver were tested for their ability to serve as templates for the DNA synthesis by means of reverse transcription in the presence of the oligo(dT) primer and the RNA-directed DNA-polymerase from avian myeloblastosis virus . The mT-mRNA does not support the DNA synthesis in the standard conditions sufficient for effective reverse transcription of rabbit globin mRNA and of poly(A) in the presence of oligo(dT) primers . After a mild alkaline treatment of the mRNA and subsequent polyadenylation of the 3'-termini of the generated fragments with ATP:RNA adenyltransferase from E.coli the poly(A) (+) polyribonucleotides are able to serve as templates for reverse transcription in the presence of oligo(dT) and the reverse transcriptase . A conclusion is made that a "structural stop" exists in mitochondrial mRNA non-translable regions adjacent to the poly(A) terminal sequence . The "structural stop" is suggested to be caused by post-transcriptional modification of mRNA (methylation, etc.) or by a particularly stable secondary structure in this region of the mRNA molecules.

Eur Surg Res, 1978, 10(1), 63 - 72
Changes in plasminogen levels, plasmin activity and activity of antiplasmins during endotoxin shock in dogs; Aasen AO et al.; Antiplasmin activity was studied during various stages of lethal canine endotoxin shock by means of assays utilizing a new chromogenic tripeptide derivative (S-2251 AB Kabi Peptide Research Division, Molndal, Sweden) . By applying a preincubation time of 30 sec and 5 min, respectively, 'immediate' and 'time-dependent' antiplasmin activities were determined . During shock gradually decreasing values of 'immediate' antiplasmin activity was observed . 'Time-dependent' antiplasmin activity also revealed a decreasing pattern, these changes, however, were less pronounced when compared with 'immediate' antiplasmin activity . The changes of plasma antiplasmin activities observed were accompanied by decreasing values of plasminogen and evidence of plasmin activity . alpha-Antitrypsin and alpha2-Macroglobulin quantitated with electroimmunoassay technique also revealed decreasing patterns during shock.

Membr Biochem, 1978, 2(1), 63 - 79
Cation-sugar cotransport in the melibiose transport system of Escherichia coli; Tsuchiya T et al.; The entry of Na+ or H+ into cells of Escherichia coli via the melibiose transport system was stimulated by the addition of certain galactosides . The principal cell used in these studies (W3133) was a lactose transport negative strain of E . coli possessing an inducible melibiose transport system . Such cells were grown in the presence of melibiose, washed, and incubated in the presence of 25 microM Na+ . The addition of thiomethylgalactoside (TMG) resulted in a fall in Na+ concentration in the incubation medium . No TMG-stimulated Na+ movement was observed in uninduced cells . In an alpha-galactosidase negative derivative of W3133 (RA11) a sugar-stimulated Na+ uptake was observed in melibiose-induced cells on the addition of melibiose, thiodigalactoside, methyl-alpha-galactoside, methyl-beta-galactoside, and galactose, but not lactose . It was inferred from these studies that the substrates of the melibiose system enter the cell on the melibiose carrier associated with the simultaneous entry of Na+ when this cation is present in the incubation medium . Extracellular pH was measured in unbuffered suspensions of induced cells in order to study proton movement across the membrane of cells exposed to different galactosides . In the absence of external Na+ or Li+ the addition of melibiose or methyl-alpha-galactoside resulted in marked alkalinization of the external medium (consistent with H+-sugar cotransport) . On the other hand TMG, thiodigalactoside, and methyl-beta-galactoside gave no proton movement under these conditions . When Na+ was present, the addition of TMG or melibiose resulted in acidification of the medium . This observation is consistent with the view that the entry of Na+ with TMG or melibiose carries into the cell a positive charge (Na+) which provides the driving force for the diffusion of protons out of the cell . It is concluded that the melibiose carrier recognition of cations differs with different substrates.

Membr Biochem, 1978, 2(1), 1 - 16
Proposed knobs-into-holes packing for several membrane proteins; Dunker AK et al.; We investigated the possible side chain/side chain interactions of four potential transmembrane proteins . The basic assumptions are that the proteins are alpha-helical, and that the proteins aggregate with knobs-into-holes packing . It was found that these four proteins can be assembled into stereochemically feasible bundles of alpha-helices with hydrophobic exteriors and with hydrogen bonds between the side chains of one alpha-helix and the side chains of its knobs-into-holes packed neighbors.

C R Seances Soc Biol Fil, 1978, 172(5), 868 - 73
{Guanyl cyclase in Escherichia coli . II . Identification and characteristics on the enzyme inhibitor}; Macchia V et al.; The activity of guanylate cyclase and that of its inhibitor present in E . coli extract, have been separated through a linear KCl gradient on DEAE-cellulose column . The activity of the inhibitor is lost after ribonuclease treatment, whereas is strengthened by addition of poly (C) . Other types of RNA synthetic homopolymers do not affect the inhibitor's activity . Chromatographic analysis of the products of guanylate cyclase measured in the presence of FI and FI plus poly (C), indicated that the inhibitor has a poly (C) dependent GTPase activity.

C R Seances Soc Biol Fil, 1978, 172(5), 860 - 7
{Guanylate cyclase in Escherichia coli . I . Purification of the enzyme and evidence for an inhibitor}; Macchia V et al.; Guanylate cyclase activity is present in crude E . coli extract . Guanylate cyclase has been purified 3500 fold from this extract, through ammonium sulfate fractionation, DEAE-cellulose chromatography . Sephadex G-75 gel-filtration and polyacrylamide gel preparative microelectrophoresis . During the purification a guanylate cyclase inhibitor has been separated.

Folia Microbiol (Praha), 1978, 23(5), 341 - 8
D-Amino acids of the amino acid pool and occurrence of racemase and D-amino acid oxidase activities in Escherichia coli B; Raunio RP et al.; Less than 20% of the amino acid content of the amino acid pool of Escherichia coli B exists in the D-form . Alanine, glutamic acid, and valine were shown by gas- chromatography to be partially in the D-form . Only D-alanine was formed by racemization in the crude extract of this organism . Alanine racemase was easily released from the membranes or vesicles but D-alanine oxidase activity remained firmly bound to the membrane . Most protein amino acids stimulated proline uptake into the vesicles, and the oxidative deamination activities were verified by the proline uptake stimulating amino acids . It is concluded that the obligatory pathway of L-amino acid--D-amino acid--oxo acid which exists in the oxidation of L-alanine does not exist with other L-amino acids . It is likely that other D-amino acids in the pool are formed in the presence of D-amino acid oxidase or D-amino acid aminotransferase.

Arch Exp Veterinarmed, 1978, 32(2), 251 - 72
{Studies on diarrhea of young calves . 1 . Quantitative analysis of the gastrointestinal flora in clinically healthy calves and in calves with diarrhea}; Schulze F et al.; Quantitative composition of gastro-intestinal-flora was determined in 23 clinically healthy calves and the course of germ spreading was followed up . In comparison with these healthy animals in 25 diarrhoea affected calves at the age of 4 to 17 days there could be observed signigicant differences only in few parts of the gastro-intestinal-tract concerning the quantitative composition of germ flora . Only in 3 animals enterotoxin producing E coli strains could be detected.

Nucleic Acids Res, 1978 Jan, 5(1), 297 - 303
Affinity adsorbents consisting of nucleic acids immobilized via bisoxirane activated polysaccharides; Potuzak H et al.; An easy and efficient procedure for the immobilization of polynucleotide ligands to bisoxirane activated insoluble polysaccharides has been elaborated and is described in this paper . The resulting materials have been applied to the chromatography of DNA polymerase I, and RNA polymerase from E.coli . Because of their extraordinary stability to temperature, formamide, and alkaline conditions they seem to be particularly useful adsorbents for nucleic acid hybridization.

Biotechnol Bioeng, 1978 Jan, 20(1), 127 - 34
A new method for cell immobilization; Petre D et al.; A new method for producing particles and membranes containing immobilized bacteria is presented . These immobilized bacteria display good stability over time making them well suited for use in a packed-bed reactor . Such a reactor is tested as a function of the different parameters of the system . The results are qualitatively similar to those obtained with purified enzyme reactors, but some discrepancies with the plug-flow model are noted . It is necessary to use a more sophisticated model in order to fit the experimental data.

J Lipid Res, 1978 Jan, 19(1), 18 - 23
Isolation and characterization of a phospholipase A2 from an inflammatory exudate; Franson R et al.; Sterile peritoneal exudates produced in rabbits injected with 1% glycogen contain a phospholipase A activity in a cell-free supernatant fraction that hydrolyzed a synthetic phospholipid (1,2-diacyl-sn-glycero-3-phospho-ethanolamine) and phospholipids of autoclaved Escherichia coli . This phospholipase activity (phosphatidylacylhydrolase EC 3.1.1.4) exhibited an apparent bimodal pH optimum (pH 6.0 and pH 7.5) and was Ca(2+)-dependent; Mg(2+) and monovalent cations (Na(+) and K(+)) did not substitute for Ca(2+) in the reaction; EDTA was a potent inhibitor . The phospholipase hydrolyzed 1-{1-(14)C}palmitoyl-2-acyl-sn-glycero-3-phosphoethanolamine to form only radio-active lysophosphatidylethanolamine as the product, indicating that the enzyme had phospholipase A(2) specificity . The phospholipase A(2) was purified 302-fold by two successive chromatographic steps on carboxymethyl Sephadex . Gel filtration (Sephadex G75) of the purified enzyme resulted in a single peak of biological activity with a molecular weight of approximately 14,800 . The same estimate of molecular weight was obtained by SDS-polyacrylamide gel electrophoresis, which yielded a single band . Polyacrylamide gel electrophoresis of this fraction at pH 4.3 revealed a single protein band migrating beyond lysozyme, with the dye front, suggesting that this protein was more basic than lysozyme (pI 10.5) . The enzymatic and physical-chemical characteristics of this soluble enzyme were remarkably similar to a recently described phospholipase A(2) of rabbit polymorphonuclear leukocytes derived from glycogen-induced peritoneal exudates . The possible origin and physiological role of this soluble enzyme are discussed.

J Bacteriol, 1978 Jan, 133(1), 139 - 48
gltB gene and regulation of nitrogen metabolism by glutamine synthetase in Escherichia coli; Pahel G et al.; A mutant (gltB) of Escherichia coli lacking glutamate synthase (GOGAT) was unable to utilize a wide variety of compounds as sole nitrogen source (e.g., arginine, proline, gamma-aminobutyrate, and glycine) . Among revertants of these Asm- strains selected on one of these compounds (e.g., arginine, proline, or gamma-aminobutyrate) were those that produce glutamine synthetase (GS) constitutively (GlnC phenotype) . These revertants had a pleiotropically restored ability to grow on compounds that are metabolized to glutamate . This suggested that the expression of the genes responsible for the metabolism of these nitrogen sources was regulated by GS . An examination of the regulation of proline oxidase confirmed this hypothesis . The differential sensitivities of GlnC and wild-type strains to low concentrations (0.1 mM) of the glutamine analog L-methionine-DL-sulfoximine supported the conclusion that the synthesis of a glutamine permease was also positively controlled by GS . During the course of this study we found that the reported position of the locus (gltB) for glutamate synthase is incorrect . We have relocated this gene to be 44% linked to the argG locus by P1 transduction . Further mapping has shown that the locus previously called aspB is in reality the gltB locus and that the "suppressor" of the aspB mutation (A . M . Reiner, J . Bacteriol . 97:1431-1436, 1969) is the locus for glutamate dehydrogenase (gdhA).

Mol Gen Genet, 1977 Dec 30, 158(2), 129 - 39
Improved electrophoretic and immunochemical techniques for the identification and characterization of mutant proteins, applied to ribosomal protein S8 in Escherichia coli mutants; Zubke W et al.; The ribosomal proteins of 11 mutants which are sensitive to starvation at elevated temperature and of 36 transductants derived from them were studied with several electrophoretic, immunochemical and proteinchemical methods . The following results were obtained: (1) Ribosomal protein S8 is altered in three of these mutants . (2) The amino acid exchange in proteins S8 of mutant N4128 is Glu leads to Lys in position 59 of the protein chain . (3) Temperature sensitivity and inability to recover from starvation at elevated temperatures are caused by the same mutational event which is, however, unrelated to the alteration in protein S8 . Several electrophoretic and immunological procedures were applied during the characterization of these mutants . A modified immunoelectrophoresis on cellulose acetate gels was developed, and proved to be the most applicable procedure for the detection of mutationally altered ribosomal proteins . This procedure may gain general importance for detecting mutational alterations in other proteins.

Biochemistry, 1977 Dec 27, 16(26), 5764 - 9
Accumulation of immunoglobulin messenger ribonucleic acid in immunized mouse spleen; Honjo T et al.; We have measured the concentration of mRNAs coding for immunoglobulins, k and lambda type light chains and gamma 1 type heavy chain, in mouse spleen cells activated by bacterial lipopolysaccharide or sheep red blood cells . These mRNAs were quantitated by hybridization to radioactive DNA complementary to highly purified immunoglobulin mRNAs from mouse myelomas . In the lipopolysaccharide-stimulated spleen cells, only light chain mRNA accumulated, whereas gamma 1 type heavy chain mRNA remained unvaried . The light chain mRNA concentration also increased in purified bone-marrow-derived lymphocytes . The lipopolysaccharide-induced light chain mRNA was similar to light chain mRNAs purified from myelomas . The accumulation and disappearance of light chain mRNA in bone-marrow-derived lymphocytes coincide with the kinetics of synthesis of immunoglobulin M which is the major species induced by lipopolysaccharide . In sheep red blood cell stimulated spleen, the specific accumulation of k type light chain and gamma 1 type heavy chain mRNAs parallels immunoglobulin G synthesis . These results seem to indicate that the increment of immunoglobulin mRNA concentration in bone-marrow-derived lymphocytes is important for induction of immunoglobulin synthesis.

J Biol Chem, 1977 Dec 25, 252(24), 8945 - 9
Purification and some novel properties of Escherichia coli RNase II; Gupta RS et al.; RNase II of Escherichia coli (EC 3.1.4.23) has been purified to apparent homogeneity . The K+-activated diesterase activity against poly(U), which defines RNase II, cochromatographs with activity against T4 mRNA or pulse-labeled E . coli RNA successively on DEAE-cellulose, hydroxyapatite or phosphocellulose, and Sephadex G-150 columns . Activities with both substrates are selectively reduced to less than 2% of the wild type level in a newly isolated mutant strain, S296, or after thermal inactivation in a mutant strain with temperature-sensitive RNase II . RNase II releases 5'-XMP without a lag as its only detectable alcohol-soluble produce from all substrates and has an apparent molecular weight of 80,000 to 90,000 in both nondissociating and sodium dodecyl sulfate-polyacrylamide gels . The pure enzyme shows the standard K+ activation against poly(A), poly(U), or poly(C), but only a slight preference for K+ over Na+ ions with T4 mRNA or pulse labeled E . coli RNA as substrate . Uniformly labeled E . coli rRNA or tRNA is degraded little if at all.

Nature, 1977 Dec 15, 270(5638), 580 - 5
Conjugation proteins encoded by the F sex factor; Kennedy N et al.; Chimaeric plasmids carrying EcoRI fragments of the F sex factor have been used to identify proteins involved in conjugation and to assign them to tra cistrons . Most of these proteins are incorporated into the cell envelope and are individually regulated at the post-transcriptional level.

Experientia, 1977 Dec 15, 33(12), 1631 - 2
In vivo effects of Escherichia coli endotoxin on sulfobromophthalein clearance in the guinea-pig; Utili R et al.; In vivo studies indicated that the primary effects of E . coli endotoxin on hepatic clearance of sulfobromophthalein were at the excretory level . Newborns were more sensitive to the LPS than older animals.

Mol Gen Genet, 1977 Dec 14, 158(1), 11 - 5
Inhibition of thymidine phosphorylase in vivo provides a rapid method for switching DNA labeling; Womack JE; Uridine blocks the in vivo conversion of thymine to thymidine in Escherichia coli, thus, one can change DNA labels by labelling first with a thymine label (e.g . 14C) and then, at the time of the change, adding 50 microgram uridine per ml and thymidine (e.g . 3H) . The cells immediately start using the thymidine, ignore the thymine for several generations, and are not affected by the uridine.

Mol Gen Genet, 1977 Dec 14, 158(1), 101 - 9
Origin of replication, oriC, of the Escherichia coli chromosome: mapping of genes relative to R.EcoRI cleavage sites in the oriC region; von Meyenburg K et al.; A precise genetic-physical map of the tna-ilv region at 82 min on the genetic map of E . coli is obtained through deletion mapping and analysis by restriction endonuclease EcoRI of plasmids, derived from an F' carrying the genes between aroE and ilv . A locus, designated het, which in its diploid state results in slow growth and heterogeneity of cell size due to distorted cell division, maps between bglB and asn, 30-45 kb counterclockwise of ilv . The pattern of R.EcoRI cleavage sites in the het region is identical with the pattern obtained by Marsh and Worcel (1977) who analyzed DNA labeled preferentially in the region of the DNA replication origin (oriC) . We suggest that oriC is identical with the het site and that it can be allocated to a position 32 kb counterclockwise of the ilv operon.

Mol Gen Genet, 1977 Dec 14, 158(1), 1 - 9
Exchange of individual ribosomal proteins between ribosomes as studied by heavy isotope-transfer experiments; Subramanian AR et al.; Whether the individual ribosomal proteins undergo exchange between robosomes in vivo during cell growth was examined using heavy isotope transfer methodology . E . coli was grown first in a heavy isotope medium in the presence of {3H} leucine and then transferred to normal medium and allowed to grow for one generation in the presence of {14C} leucine . The "heavy" and "light" ribosomes that were present in such cells were separated by sedimentation and the ribosomal proteins resolved by two-dimensional gel electrophoresis . The individual proteins were burnt in O2 and their contents of {3H} and {14C} labels determined . From the analysis of the data we find that the great majority of the ribosomal proteins of E . coli does not undergo exchange during cell growth . Proteins which were found to exchange to varying levels in different transfer experiments were S1, S2, L7/L12, L9, L10 and L33 . All of them except L9 exchanged to the same levels in control experiments in which separately grown heavy and light cells were mixed and processed . These proteins therefore undergo exchange during cell breakage and ribosome isolation . Protein L9 consistently showed appreciably greater exchange in transfer experiments as compared to the controls suggesting that it may exchange in vivo.

Biochim Biophys Acta, 1977 Dec 14, 479(4), 471 - 8
Effects of pH on the properties of normal and 5-fluorouracil-containing tRNAs; Moore VG et al.; Transfer RNAs isolated from Escherichia coli B grown in the presence of 5-fluorouracil (FIUra) show variations in their aminoacylation levels when compared with normal samples . Some of these variations result from the more stringent aminoacylation reaction conditions required for FIUra-tRNAs . Increasing the reaction pH from 7 to 9 for example, generally causes a lowering of amino acid acceptance by the analog-containing tRNAs, while leaving control samples largely unchanged . This decreased activity appears to result primarily from fluorouracil ionization, which in turn disrupts intramolecular hydrogen bonding and promotes an overall increase in the molecular dimensions of FIUra-tRNAs at elevated pH values . Sensitivity to pH differes with the amino acid examined, with lysine showing dramatic changes and glutamine and proline being largely unaffected.

Biochemistry, 1977 Dec 13, 16(25), 5625 - 31
Mutations in Escherichia coli altering an apurinic endonuclease, endonuclease II, and exonuclease III and their effect on in vivo sensitivity to methylmethanesulfonate; Kirtikar DM et al.; The levels of endonuclease II, an apurinic endonuclease, and exonuclease III in the parent strains (AB 1157) of Escherichia coli and in various mutants were determined by chromatography on DEAE-cellulose . AB 3027 and NH 5016 lacked endonuclease II and exonuclease III . BW 2001 lacked the apurinic endonuclease and exonuclase III while BW 2007, BW 9093, and BW 9059 lacked only exonuclease III . Deletion mutants BW 9101 and BW 9109 lacked all three enzymes . The latter mutants locate the genes for the two endonucleases in the region of exonuclease III (chith) of 38.2 min (White et al., 1976) . All of the mutants which were sensitive to methylmethanesulfonate in vivo lacked exonuclease III, but not all mutants lacking exonuclease III were MMS sensitive . The deletion mutants and NH 5016 were the exceptions.

Biochemistry, 1977 Dec 13, 16(25), 5414 - 20
Interaction of oligoribocytidylates with T7 DNA in neutral and acid media; Sarocchi-Landousy MT et al.; Oligoribocytidylates of chain length 4 to 12 were found to interact with native T7 DNA at neutral and slightly acid pH . The results suggest that binding occurred at deoxycytosine clusters which may be displaced by the oligomers at neutral pH, while a local triple-stranded structure would be formed at acid pH . Transcription of DNA-(Cp)n complexes by Escherichia coli RNA polymerase showed a decrease in level without affecting the specificity of the transcription, suggesting that oligocytidylate binding did not occur on the promoters.

Science, 1977 Dec 9, 198(4321), 1056 - 63
Expression in Escherichia coli of a chemically synthesized gene for the hormone somatostatin; Itakura K et al.; A gene for somatostatin, a mammalian peptide (14 amino acid residues) hormone, was synthesized by chemical methods . This gene was fused to the Escherichia coli beta-galactosidase gene on the plasmid pBR322 . Transformation of E . coli with the chimeric plasmid DNA led to the synthesis of a polypeptide including the sequence of amino acids corresponding to somatostatin . In vitro, active somatostatin was specifically cleaved from the large chimeric protein by treatment with cyanogen bromide . This represents the first synthesis of a functional polypeptide product from a gene of chemically synthesized origin.

Mol Gen Genet, 1977 Dec 9, 157(3), 341 - 4
In vitro construction of plasmids which result in overproduction of the protein product of the araC gene of Escherichia coli; Steffen D et al.; Derivatives of the Escherichia coli drug resistance plasmid pMB-9 were constructed which contain the promoter from the lactose operon of E . coli fused to the araC gene of E . coli . E . coli possessing these plasmids contain about 50 times as much of the araC gene product as do cells with a wild-type araC gene and promotor.

Biochim Biophys Acta, 1977 Dec 8, 485(2), 452 - 64
Thiol groups of Escherichia coli citrate synthase and their influence on activity and regulation; Danson MJ et al.; The modification of Escherichia coli citrate synthase (citrate oxaloacetatelyase(pro-3S-CH2.COO- leads to acetyl-CoA, EC 4.1.3.7) with 5,5'-dithiobis-(2-nitrobenzoic acid) has been investigated . (1) In low ionic strength (20 mM Tris.HCl, pH 8.0): (A) Eight thiol groups per tetramer of the native enzyme reacted with Nbs2 . (b) Two of the eight accessible thiols were modified rapidly with the loss of 26% enzyme activity but with no change in the NADH inhibition . The remaining six were modified more slowly, resulting in a further 60% loss of activity and complete densensitization to NADH . (c) The 2nd-order rate constant for the modification of the rapidly reacting thiols is 2.5.10(4) M-1.min-1 . At the reagent concentrations used (0.1 to 0.2 mM) the modification of the six thiols in the slow kinetic set appeared to be 1st-order; at 0.1 mM dithionitrobenzoic acid their rate of modification was approximately 30 times slower than the thiols in the fast kinetic set . (2) In high ionic strength (20 mM Tris.HCl, pH 8.0, 0.1 M KCl): (a) Four thiol groups were modified in a single kinetic set and it appeared that these thiols are four of the six slowly modified in the absence of KCl . (b) The modification resulted in 70% loss of enzyme activity and complete loss of NADH inhibition . (3) From the kinetic analysis it is proposed that the four thiol groups accessible to dithionitrobenzoic acid in the absence and presence of 0.1 M KCl are those involved in the response of NADH . Modification of any one of these four groups produced no reduction in the inhibition; instead, loss of NADH sensitivity was coincident with the appearance of tetrameric protein possessing three substituted thiols, whereas enzyme with one or two modified groups was still fully inhibited by NADH.

Jpn J Surg, 1977 Dec, 7(4), 223 - 9
Disseminated intravascular coagulation in the pathogenesis of adult respiratory distress syndrome: 2 . Experimental study; Ogawa R et al.; The role of disseminated intravascular coagulation (DIC) in the pathogenesis of adult respiratory distress syndrome (ARDS) was studied in the experimental animals . ARDS was simulated in dogs by the administration of various doses of Escherichia coli endotoxin (Difco) . The alveolar surface activity in the group which received lethal dose of endotoxin (3 mg/kg) exhibited no significant alterations with mild pulmonary insufficiency and little pathologic change five hours after the induction of shock . On the other hand, a significant decrease in alveolar surface activity was found to develop in the group which received sublethal dose of endotoxin (1 mg/kg) accompanying enlarged alveolar-arterial oxygen tension differences (A-aDO2) and elevated pulmonary vascular resistance after 24 hours . These changes occurred concomitantly with pathologic findings of DIC, interstitial edema and atelectasis . The disturbance in ventilatory function observed in prolonged shock appeared to be related to the impairment of pulmonary microcirculation caused by DIC and subsequent hypoxia of lung tissue which led to a loss of alveolar surfactant.

Eur J Biochem, 1977 Dec 1, 81(2), 285 - 91
Joining of synthetic ribotrinucleotides with defined sequences catalyzed by T4 RNA ligase; Ohtsuka E et al.; RNA ligase catalyzed the joining of pC-C-Ap with C-A-A in the synthesis of C-A-A-C-C-Ap, which has the sequence of the Escherichia coli tRNAfMet 3'-end . pC-C-A was also shown to be joined to C-A-A without any undesired self-polymerization . Joining of pC-C-A to various synthetic ribotriplets, such as C-C-A, A-A-A, C-C-C, U-U-U, U-A-G, C-C-G and U-U-C, was performed as well as joining to the partially substituted trimers with a photolabile o-nitrobenzyl group, C-Anbzl-A and C-C-Anbzl . The yields were C-A-A-C-C-A (69%), C-C-A-C-C-A (38%), A-A-A-C-C-A (66%), C-C-C-C-C-A (71%), U-U-U-C-C-A (50%), U-A-G-C-C-A (23%), C-C-G-C-C-A (43%) and U-U-C-C-C-A (46%) . C-Anbzl-A was a slightly poorer acceptor than C-A-A and C-C-Anbzl did not serve as an acceptor . Recognition of acceptor molecules by RNA ligase is discussed in terms of affinity of oligonucleotides for the enzyme.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5529 - 33
In vitro degradation of guanosine 5'-diphosphate, 3'-diphosphate; Sy J; The degradation of guanosine 5'-diphosphate,3'-diphosphate (ppGpp) by the "crude" ribosomal fraction of Escherichia coli CP78 (rel+, spoT+) was demonstrated and characterized . When the 3'-pyrophosphoryl group of ppGpp was hydrolyzed, the primary degradation product was 5'-GDP . Phosphorylation of ppGpp to guanosine 5'-triphosphate,3'-diphosphate (pppGpp) prior to degradation was not necessary . The degradation process required Mn2+ and was inhibited by EDTA . Levallorphan, an inhibitor of in vivo ppGpp degradation, also inhibited ppGpp degradation by the crude ribosome . Thiostrepton and tetracycline did not have any inhibitory effect, indicating that the reaction is not a reversal of pyrophosphorylation catalyzed by the stringent factor/ribosome complex . Crude ribosome fractions from E . coli NF161 and NF162, both spoT-, contained little degrading activity, but similar fractions of E . coli CP79, a relA- and spoT+ strain, contained ppGpp degrading activity.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5411 - 5
Use of gene fusions to study outer membrane protein localization in Escherichia coli; Silhavy TJ et al.; Escherichia coli strains have been isolated that produce hybrid proteins comprised of an NH2-terminal sequence from the lamB gene product (an outer membrane protein) and a major portion of the COOH-terminal sequence of beta-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23; a cytoplasmic protein) . These proteins exhibit beta-galactosidase activity . One such strain, pop 3105, produces a hybrid protein containing very little of the lamB gene protein; the protein is found in the cytoplasm . The protein found in a second strain, pop 3186, contains much more of the lamB gene protein; a substantial fraction of the beta-galactosidase activity is found in the outer membrane, probably facing outward . These results indicate that information necessary to direct the lamB gene product to its outer membrane location is located within the lamB gene itself . The properties of such fusion strains open up the prospect of a precise genetic analysis of the genetic components involved in protein transport.

Nucleic Acids Res, 1977 Dec, 4(12), 4323 - 45
Studies on the primary structure of the ribosomal 23S RNA of Escherichia coli: II . A characterisation and an alignment of 24 sections spanning the entire molecule and its application to the localisation of specific fragments; Branlant C et al.; We have employed new methodology to obtain 23S RNA fragments which includes a) the digestion of the RNA within 50S subunits and b) the limited hydrolysis of the 13S and 18S fragments . By comparing all 23S RNA fragments, obtained heretofore, we have characterised and aligned 24 sections of this RNA spanning nearly the entire molecule . These results allow the localisation of any new 23S RNA fragment by comparison of the fingerprint of its T1 ribonuclease digest to the characteristic ones of the different sections . In this way we obtained a more definite localisation of the binding sites of the 50S proteins L1, L5, L9, L18, L20, L23 and L25 . We also specified a ribonuclease sensitive region of 23S RNA in native 50S subunits, extending from the 1100th nucleotide from the 5' end to the 1000th nucleotide from the 3' end; this region contains a cluster of 5 modified nucleotides and may be at the subunit interface.

Can J Microbiol, 1977 Dec, 23(12), 1683 - 8
The electrochemical proton gradient and phenylalanine transport in Escherichia coli irradiated with near-ultraviolet light; Sprott GD et al.; Irradiation of Escherichia coli with near-ultraviolet (near-UV) light diminished the electrochemical proton gradient and the accumulation of L-phenylalanine . Inhibitors known to collapse the proton gradient and the comparison of two techniques measuring the electrical potential substantiated the estimates made . At several fluences (doses), a linear relationship was observed between the phenylalanine gradient and the combined electrical and chemical potentials (the electrochemical proton gradient), suggesting a close coupling between them . However, additional effects of near-UV light on the phenylalanine permease were not discounted . The combined potentials provided sufficient energy for the observed accumulation of phenylalanine, assuming a proton to amino acid cotransport ratio of 1 . An increase in membrane permeability did not contribute to the loss of phenylalanine transport, as shown by an increase in the rate and extent of alpha-methylglucoside uptake.

J Bacteriol, 1977 Dec, 132(3), 884 - 95
Cell cycle analysis of F'lac replication in Escherichia coli B/r; Finkelstein M et al.; The timing and control of replication of an F'lac plasmid was investigated in two substrains of Escherichia coli B/r lac/F'lac growing at a variety of rates . The cellular content of covalently closed circular F'lac deoxyribonucleic acid and the cellular mass at the time of F'lac replication both increased as a function of growth rate . The timing of plasmid replication during the division cycle was determined by measuring the inducibility of beta-galactosidase in cells of different ages in exponentially growing cultures . At all growth rates, the rate of induced beta-galactosidase synthesis increased in a step-wise fashion during the division cycle, indicating that the F'lac plasmid replicated at a discrete time in the cycle . At growth rates greater than one doubling per h, the cell age at F'lac replication was indistinguishable from the cell age at chromosomal lac+ replication in an isogenic F- parent . The ratio of plasmids to chromosomal origins decreased from about 0.7 to 0.4 between growth rates of 1.0 to 2.5 doublings per h . These observations are all consistent with replication of F'lac at about the same time in the division cycle as replication of the homologous chromosomal region at these growth rates . This similarity in timing of replication of homologous deoxyribonucleic acid regions was not evident in slower-growing cells.

J Bacteriol, 1977 Dec, 132(3), 876 - 83
In vitro synthesis of beta-galactosidase with ilv-lac fusion deoxyribonucleic acid as template; Wild J et al.; An in vitro protein-synthesizing system has been developed to study the mechanism of induction of ilvC gene in Escherichia coli strain K-12 . Deoxyribonucleic acid (DNA) from a lambda phage carrying an ilvC-lac fusion was employed as a template for the in vitro synthesis of beta-galactosidase under the control of the ilvC promoter . The use of this template allowed an investigation of the components required for induction of the ilvC gene and the kinetics of the induction . The in vitro synthesis of beta-galactosidase under the control of the ilvC promoter was found to be DNA, acetohydroxy acid, and guanosine-3'-diphosphate-5'-diphosphate dependent, and sensitive to rifampin, actinomycin D, and chloramphenicol . Uncoupling experiments indicate that the inducer, acetohydroxybutyrate, acts at the transcriptional level . Investigation of a proposed noninducible ilvC regulatory mutant has shown normal induction in vitro . It was also observed that an intact ilvA gene is not required for the induction of the ilvC gene.

Inflammation, 1977 Dec, 2(4), 265 - 76
Influence of extracellular Ca2+ and Mg2+ on chemotactic factor-induced neutrophil aggregation; O'Flaherty JT et al.; The influences of extracellular Ca2+ and Mg2+ on chemotactic factor-induced rabbit polymorphonuclear neutrophil (PMN) aggregation was studied using a recently described Coulter counter assay technique . Compared with those of other PMN functional assays (adhesion, chemotaxis, degranulation, and phagocytosis), the cation requirements for cell aggregation appear unique . Chemotactic factor-induced aggregation did not occur in the absence of either cation . When the concentration of both cations was increased equivalently, aggregation increased . The effect plateaued at 2.8 mM of Ca2+ and Mg2+ . When the concentration of one cation alone was increased, aggregation peaked . Further increases inhibited maximal aggregation . By systematic variation of the cation concentrations, optimal aggregation was found at Ca2+ and Mg2+ concentrations of 2.8 mM . At these concentrations, significant aggregation was induced with chemotactic doses of bacterial factor, the chemotactic fragment of human C5, and the synthetic chemotactic tripeptide, formyl-met-leu-phe . Thus, under these conditions, chemotactic factor-induced aggregation of neutrophils may be a useful indicator of interactions of chemotactic factors with neutrophils.

Early Hum Dev, 1977 Dec, 1(3), 227 - 45
Drip breast milk: it's composition, collection and pasteurization; Gibbs JH et al.; "Drip breast milk" is that milk which spontaneously drips from the contralateral breask during the suckling of an infant . Biochemically and immunologically, pooled drip milk resembled pooled mature expressed breast milk, although it has a lower fat concentration . About 15% of lactating women are capable of producing drip milk; volumes produced are up to 188 ml/donor/day . A milk bank is described which processes 1400 liters of drip milk/yr . Heat treatment of this milk with a semi-automated holder pasteurizer caused a 21% reduction in IgA concentration and a 36% reduction in lysozyme activity, as well as a decrease in the ability of the milk to inhibit the growth of E . coli . In comparison with boiling, pasteurization was as effective in reducing total bacterial content provided the milk initially contained fewer than 10(6) bacteria/ml.

Southeast Asian J Trop Med Public Health, 1977 Dec, 8(4), 476 - 9
Heat-labile enterotoxigenic Escherichia coli and intestinal protozoa in asymptomatic travellers; Echeverria P et al.; Thirty-two asymptomatic travellers who had recently journeyed in the Near, Middle, and Far East and had experienced a high incidence of diarrhoeal disease were screened for heat-labile enterotoxigenic Escherichia coli (ent+ E . coli) and other bacterial and parasitic pathogens . Six percent were colonized with ent+ E . coli and while other bacterial pathogens were not found, the intestinal protozoa Giardia lamblia (13%), Entamoeba histolytica (6%), Entamoeba coli (6%), Endolimax nana (6%), and Entamoeba hartmanni (3%) were detected in the stools . Ent+ E . coli, G . lamblia and E . histolytica should be considered in the differential diagnosis of gastrointestinal disease in travellers returning from the Orient . Furthermore, these travellers may be a potential source for the introduction of ent+ E . coli into communities where such organisms are relatively rare.

Environ Health Perspect, 1977 Dec, 21, 61 - 4
Metabolism and mutagenicity of halogenated olefins--a comparison of structure and activity; Henschler D; Chlorinated ethylenes are metabolized in mammals, as a first step, to epoxides . The fate of these electrophilic intermediates may be reaction with nucleophiles (alkylation), hydrolysis, or intramolecular rearrangement . The latter reaction has been studied in the whole series of chlorinated epoxiethanes . The rearrangement products found were: acyl chlorides (tetrachloro-, trichloro-, and 1,1-dichloroethylenes), or chlorinated aldehydes (1,2-dichloroethylenes, cis- and trans-, vinyl chloride) . The metabolities found in vivo are identical with, or further derivatives of these rearrangment products, with one important exception: trichloroethylene . With this compound, in vivo rearrangement yields chloral exclusively . The mechanism of the different rearrangement has been identified as a Lewis acid catalysis . All chlorinated ethylenes have been investigated in a tissue-mediated mutagenicity testing system . The prominent molecular feature of those with mutagenic effects (trichloro-, 1,1-dichloro-, and monochloroethylene) is unsymmetric chlorine substitution which renders the epoxides unstable, whereas symmetric substitution confers relative stability and nonmutagenic property.

Rev Can Biol, 1977 Dec, 36(4), 307 - 16
{Production of colicins V and V2 in vitro and in vivo . Study of their inhibitory action on phagocytosis by peritoneal macrophages}; Ozanne G et al.; In recent years, a possible relationship between pathogenicity and colicinogeny in some Escherichia coli colicin V-producing strains had been inferred . In our laboratory, we have elaborated a simple in vitro method for the production of colicin V free of large, non dialyzable macromolecules and presumably of bacterial endotoxin . This allows study of the effects of colicin V in vivo without an undesirable added physiological response of the experimental animal to endotoxin . All the Col V+ strains we have studied displayed a greater ability to survive in the peritoneal cavity of mice than the Col V- strains . Also, we have detected colicin V in peritoneal fluids of agonizing mice injected with Col V+ strains . Phagocytosis by peritoneal macrophages seemed to be inhibited in vitro in the presence of colicin V . Colicin V is not toxic in vivo in low concentration, after intraperitoneal or intravenous injection but it may favor the multiplication and the invasiveness of the strains that produce it.

Acta Pathol Microbiol Scand {B}, 1977 Dec, 85B(6), 449 - 54
Bacteriuria and renal infection in kidney-transplant recipients; Thomsen OF et al.; In 64 patients who had undergone renal transplantation, later on followed by bilateral nephrectomy, bacterial growth culture was performed from the original kidneys . The presence of bacteria in the nephrectomy specimens was compared with the occurrence of significant bacteriuria before transplantation and in the period between transplantation and nephrectomy . Bacteria could be cultured from the nephrectomy specimens of 18 (28.1 per cent) of the patients, almost exclusively confined to cases of obstructive chronic pyelonephritis, analgesic nephropathy and congenital renal disease . Before transplantation, bacteriuria had been recorded in 34.4 per cent of the patients, most frequently in the three groups of diseases just mentioned . Between the transplantation and nephrectomy, bacteriuria occurred in 75.0 per cent of the patients . Patients with E . coliuria before transplantation were particularly liable to have E . coliuria also after the transplantation and to E . coli in the nephrectomy specimens, whereas patients in whon E . coliuria did not occur until in the post-transplantation period were less susceptible to E . coli infection involving the kidneys . Probably the presence of bacteria in the nephrectomy specimens is related to the primary disease rather than to immunosuppressive and antiobiotic agents administered in the post-transplantation period.

Br J Haematol, 1977 Dec, 37(4), 515 - 20
Myelotoxicity of methotrexate in animals with pyogenic infection; Harding B et al.; Rats stimulated into prolonged increased neutrophil production by the induction of a unilateral pyo-hydronephrosis showed consistent profound neutropenia when methotrexate (MTX) was given during the first 2 d of infection . Thereafter greater neutropenia than that observed in non-infected rats was only observed in occasional animals . There was a significant correlation between the degree of neutropenia induced by MTX and the day after MTX upon which this occurred . The main target for myelotoxicity by MTX appears to be the myelocyte . Its precursors seem relatively insensitive.

Urology, 1977 Dec, 10(6), 539 - 43
Renal failure associated with vesicoureteral reflux; Anderson JD et al.; In a review of over 600 charts with a major diagnosis of vesicoureteral reflux only 21 were found to have coexisting azotemia . Nine of 11 patients treated surgically with technically successful operations had either improvement or stabilization of their renal function . All such cases had moderate degrees of azotemia (creatinine of less than 3.5 mg . per 100 ml.) . Surgery is recommended in cases of gross reflux and in cases with evidence of parenchymal damage, before deterioration in renal function has become irreversible.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5632 - 6
Isolation and characterization of a lambdapolA transducing phage; Kelley WS et al.; A plaque-forming lambdapolA phage was isolated from a population of transducing phage made in vitro from Escherichia coli DNA and a phage vector digested with restriction endonuclease HindIII . Amber mutations, in genes whose products are necessary for late protein synthesis (Q) and cell lysis (S), were crossed into the lambdapolA phage . Infection of either polA+ or polA- bacteria with this phage, under conditions permitting DNA replication but preventing phage production and lysis, elevated the levels of DNA polymerase I to between 75- and 100-fold that detected in a wild-type strain . The kinetics of enzyme production suggest that the polA gene is transcribed from its own promoter rather than from any of the well-characterized phage promoters . The fragment of E . coli DNA within the lambdapolA phage comprises approximately 5000 base pairs, sufficient to accommodate the polA gene and one, or two, coding sequences for smaller proteins.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5547 - 50
Contrast variation study of specifically deuterated Escherichia coli ribosomal subunits; Crichton RR et al.; A neutron small-angle scattering analysis has been done on partially deuterated 30S and 50S subunits of Escherichia coli ribosomes by the contrast variation method . The results indicate that the central regions of both particles are RNA-rich whereas their exteriors are protein-rich . The segregation of RNA and protein is much greater in the 50S subunit than in the 30S; the 30S subunit approaches a homogeneous mixture of RNA and protein . In both structures the most probable separation between the centers of mass of their protein and RNA distributions is small, although substantial variation of this parameter is possible within experimental error.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5509 - 13
Initiation of polypeptide synthesis with various NH2-blocked aminoacyl-tRNAs under the direction of alfalfa mosaic virus RNA 4; Castel A et al.; Initiation of polypeptide synthesis in a cell-free system of Escherichia coli directed by alfalfa mosaic virus RNA 4 was studied by using either fMet-tRNA or Ac-Phe-tRNA as initiator tRNA . Initiation with fMet-tRNA yielded a product that was identical to the authentic viral coat protein except that the NH2-terminal serine was preceded by fMet instead of being acetylated . When Ac-Phe-tRNA was used as initiator, the biosynthetic product was 10-12 amino acid residues longer, the extra amino acids being located at the NH2-terminus . fMet-tRNA and Ac-Phe-tRNA did not compete for ribosomes during initiation of protein synthesis, as became evident from incorporation studies using both initiator tRNAs simultaneously . It is concluded that E . coli ribosomes recognize two sites on the 5' end of alfalfa mosaic virus RNA 4 that are separated by a region of about 30 nucleotides . The results are in complete agreement with the 5'-terminal nucleotide sequence of this RNA {Koper-Zwarthoff, E . C., Lockhard, R . E., RajBhandary, U . L., Alzner-deWeerd, B . & Bol, J . F . (1977) Proc . Natl . Acad . Sci . USA 74, 5504-5508}.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5496 - 8
Codon specificity of UGA suppressor tRNATrp from Escherichia coli; Buckingham RH et al.; A synthetic polyribonucleotide, poly(U5,G), was used to study the codon specificity of wild-type and UGA suppressor tRNATrp from Escherichia coli . Phe (UUU) incorporation directed by this synthetic messenger is reduced somewhat by omission from the incubation mixtures of Val (GUU), Leu (UUG), or Cys (UGU) . In contrast, omission of Cys stimulates Trp incorporation, and this effect is much more pronounced with the UGA suppressor tRNATrp than with wild-type tRNA . The apparent replacement of Cys by Trp is specific, because the omission of Val or Leu slightly inhibits Trp incorporation . These data suggest that the UGA suppressor tRNATrp can translate codons of the form UGN (N is any ribonucleotide) . In other words, the suppressor tRNATrp translates codons that properly match two out of the three anticodon nucleotides.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5458 - 62
Cloning and mapping of the replication origin of Escherichia coli; Yasuda S et al.; The replication origin of Escherichia coli has been cloned on a nonreplicating DNA fragment coding for ampicillin resistance . This recombinant DNA, named pSY211, replicates depending on the presence of the replication origin and can be recovered as a closed circular plasmid DNA of 10.7 megadaltons (Mdal) . A restriction map has been constructed . EcoRI cleaves pSY211 into two fragments: one is the ampicillin fragment of 4.5 Mdal and the other is a chromosomal fragment of 6 Mdal and contains the origin . The 6 Mdal EcoRI fragment has four BamHI sites, three HindIII sites, and one Xho I site . A mutant of pSY211 has been isolated which is lacking two BamHI fragments of the chromosomal fragment . In recA hosts, pSY211 is lost at a high frequency . In recA+ hosts, pSY211 is integrated into the chromosome due to nucleotide sequence homology between pSY211 and the replication origin of the E . coli chromosome . The integration site has been mapped . We conclude that the replication origin is located at a site between uncA and rbsK, at about 83 min on the genetic map of E . coli.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5416 - 20
Regulation of synthesis and activity of a mutant RNA polymerase in Escherichia coli; Dennis PP; The expression of the genes specifying the beta and beta' subunits of RNA polymerase (nucleosidetriphosphate: RNA nucleotidyltransferase, EC 2.7.7.6) was examined in an Escherichia coli strain bearing a temperature-sensitive mutation in the beta' subunit gene . A shift to 42 degrees results in a restriction of RNA chain initiation and a cessation of RNA synthesis . A shift to 39 degrees results in only partial restriction, allowing RNA and protein synthesis to continue . The partial restriction produces a 5- to 6-fold increase in the relative transcription rate of the beta and beta' genes and a concomitant increase in the relative synthesis rate of the beta and beta' proteins . The transcription rate of ribosomal protein genes was also increased somewhat . These results indicate that the genes specifying the beta and beta' subunits of RNA polymerase are regulated at the level of transcription and that this regulation is related to the transcription of ribosomal protein genes . Furthermore, the results indicate that this regulation of the beta and beta' RNA polymerase subunit genes is somehow triggered by a reduction in the ability of RNA polymerase to initiate transcription on the bacterial chromosome.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5387 - 91
mRNA-dependent in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu; Chu F et al.; RNA extracted from growing Escherichia coli can direct the in vitro synthesis of ribosomal proteins L12 and L10 and elongation factor Tu when an E . coli system is used . The synthesized L12 can be bound to L12-depleted ribosomes and the synthesized elongation factor Tu can form complexes with both elongation factor Ts and GDP . Guanosine 5'-diphosphate 3'-diphosphate has no effect on the synthesis of these proteins from an RNA template but inhibits their synthesis when a DNA template is used.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5363 - 7
Cloning of the silk fibroin gene and its flanking sequences; Ohshima Y et al.; Thirteen Escherichia coli clones containing the whole or a part of the fibroin gene (16 kilobases long) have been isolated . The starting material was DNA extracted from the posterior silk glands of Bombyx mori . Most clones were obtained from sheared DNA fragments linked by poly(dA)-poly(dT) joints to the plasmid pMB9 . One of them includes the 5' end of the fibroin gene with a flanking sequence of 12 kilobases, and another includes the 3' end of the gene with a flanking sequence of about 1 kilobase . One clone was obtained by ligation, to pMB9, of a fragment generated by endodeoxy-ribonuclease EcoRI . This clone has a 21-kilobase insertion that probably includes the entire fibroin gene with flanking sequences at both ends . The cleavage sites for endodeoxyribonucleases EcoRI, HindIII, and BamHI have been established for the cloned sequences.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5318 - 22
Biosynthesis of the covalently linked diglyceride in murein lipoprotein of Escherichia coli; Chattopadhyay PK et al.; Biosynthesis of the diglyceride moiety of murein lipoprotein in Escherichia coli was studied by pulse-labeling with {2-3H}glycerol and subsequent chase . The evidence strongly suggests that the precursor of the glycerol moiety in lipoprotein is one of the major phospholipid species in E . coli . Studies of biosynthesis of lipoprotein in cerulenin-treated cells indicated that the nonacylated glycerol moiety of phosphatidylglycerol is the donor for the formation of a thioether linkage in the glycerylcysteine residue of the lipoprotein . This is supported by the observation that carbon 1 rather than carbon 3 of sn-glycerol is involved in this thioether linkage . We propose that the biosynthesis of lipoprotein proceeds as follows: apolipoprotein + phosphatidylglycerol or acyl phosphatidylglycerol leads to lipoprotein + phosphatidic acid.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5275 - 9
Protein X is the product of the recA gene of Escherichia coli; McEntee K; The inducible protein X of Escherichia coli has been compared to the recA+ protein made by specialized recA transducing phages . The molecular weights and isoelectric points of these proteins are identical . Two mutations located in the recA gene that alter the electrophoretic mobility or the isoelectric point of protein X have been studied . A recA12 mutant strain, deficient in homologous recombination and repair, produces a smaller-than-normal protein X . A transducing phage carrying the recA12 allele directs the synthesis of a smaller recA protein after infection of irradiated cells . A transducing phage carrying the recA region of a tif-1 mutant strain codes for a recA protein with an isoelectric point more basic than that of the lambdaprecA+ product . The protein X of a tif-1 mutant strain shows an identical shift in its isoelectric properties . Examination of several tsl- recA- strains indicates that protein X can be induced in several missense recA mutants but is not detected in tsl- strains carrying amber or deletion mutations of the recA gene . These results demonstrate that protein X is the product of the recA gene and that the tif-1 mutation alters the properties of the recA protein . A model is suggested for autoregulation of the recA protein in the induction of functions expressed in response to DNA damage (SOS functions).

Nucleic Acids Res, 1977 Dec, 4(12), 4313 - 22
Genetically determined differences in concentrations of isoaccepting tRNAs in Escherichia coli; Thomale J et al.; Two examples of genetically determined altered concentrations of isoaccepting tRNAs are presented . The concentrations of isoaccepting tRNAsThr are selectively changed by a mutation causing a fourfold overproduction of the cognate aminoacyl-tRNA-synthetase, the threonyl-tRNA synthetase, whereas the distribution of isoaccepting tRNAs of four control tRNA-species in these E . coli mutants was not affected by that mutation . Secondly evidence is presented for a correlation between mutations in structural genes of aminoacid biosynthetic enzymes and alterations in concentrations of cognate isoaccepting tRNAs in two different E . coli strains, auxotrophic for threonine, isoleucine/valine and leucine, and arginine respectively.

Nucleic Acids Res, 1977 Dec, 4(12), 4249 - 60
Polynucleotides . L . Synthesis and properties of poly (2'-chloro-2'-deoxyadenylic acid) and poly (2'-bromo-2'-deoxyadenylic acid); Ikehara M et al.; Poly (2'-chloro-2'-deoxyadenylic acid) and poly (2'-bromo-2'-deoxyadenylic acid) were synthesized from the corresponding diphosphates with the aid of polynucleotide phosphorylase from E . coli . UV, CD, acid titration and mixing with poly (U) were investigated . Comparing these properties with those of poly (A) and poly (2'-azido-2'-deoxyadenylic acid), it was found that 2''substituents exert significant effects on the thermal stability of these polynucleotides, though the overall conformational structure was not greatly changed.

J Biochem (Tokyo), 1977 Dec, 82(6), 1505 - 11
Formation of ribothymidine from thymine and ribonucleosides by the cell-free extract of tumors and rat tissues; Yano S et al.; Formation of ribothymidine by the ribose exchange reaction between thymine and uridine with the cell-free extract of mouse Ehrlich ascites tumor cells was demonstrated . Since phosphate ions appear to be not required for this reaction, perhaps it proceeds by the mechnism of direct exchange of nucleoside N-ribosyltransferase . The transfer activity was found in the precipitates when the crude extract was fractionated with 30-60% saturated ammonium sulfate . Ribothymidine formation was also demonstrated between thymine and ribonucleosides other than uridine with this tumor extract . Production of ribothymidine from thymine and uridine was detected also by the use of extracts from lung, brain, and regenerating liver of normal rats, and from newborn rats (whole body) . An extract of Rhodamine sarcoma exhibited the ribose exchange activity, while that of human gastric cancer did not.

Eur J Biochem, 1977 Dec 1, 81(2), 373 - 8
Inhibition of chloramphenicol binding to Escherichia coli 70S ribosomes by 2'(3')-O-aminoacyl-dinucleoside phosphates derived from the aminoacyl-tRNA acceptor terminus; Goldberg R et al.; The effect of 2' and 3'-O-aminoacyl-dinucleoside phosphates cytidylyl(3'-5')-2'(3')-O-L-phenyl-alanyladenosine (I), cytidylyl(3'-5')-3'-deoxy-2'-O-L-phenylalanyladenosine (IIa), cytidylyl(3'-5')-2'-deoxy-3'-O-L-phenylalanyladenosine (IIIa), cytidylyl(3'-5')-3'-deoxy-2'-O-glycyladenosine (IIb), cytidylyl(3'-5')-2'-deoxy-3'-O-glycyladenosine (IIIb), cytidylyl(3'-5')-3'-deoxy-2'-O-L-leucyladenosine (IIc), cytidylyl(3'-5')-2'-deoxy-3'-O-L-leucyladenosine (IIIc), cytidylyl(3'-5')-3'-O-L-phenylalanyladenosine (IIId) as analogs of the 2'(3')-aminoacyl-tRNA termini, on chloramphenicol binding to 70S Excherichia coli ribosomes was investigated . The association constants (Kb) of the investigated compounds were determined by the equilibrium dialysis method . Based on the constancy of Kb over the range of inhibitor concentration, it was determined that the binding site of the 2' isomers IIa-IIc overlaps with the chloramphenicol site, whereas the variability of Kb for the 3' isomers IIIb, IIIc and especially IIIa seems to indicate that they do not achieve a complete fit . The consistently higher values of the Kb values for the 3' isomers IIIa-IIIc relative to that of the 2' isomers IIa-IIc also indicate a stabilization of the binding of the former due to a specific interaction between its amino acid portion and a ribosomal site.

Cell, 1977 Dec, 12(4), 1127 - 31
Questioning of reported evidence for guanosine tetraphosphate synthesis in a ribosome system from mouse embryos; Martini O et al.; In 1974, Irr, Kaulenas and Unsworth reported that ppGpp is synthesized by cytosolic ribosomes from mouse embryos and proposed a role for ppGpp in the process of differentiation . This proposal is being challenged because ribosomes of mouse embryos from various stages of development and of mouse embryoid bodies were completely inactive in ppGpp formation.

Can J Biochem, 1977 Dec, 55(12), 1207 - 12
Synthesis of pppGpp by ribosomes from an Escherichia coli spoT mutant and the metabolic relationship between pppGpp and ppGpp; Leung KL et al.; Both ribosomes and a cell-free extract (S-30) prepared from an Escherichia coli spoT mutant catalyzed the synthesis of guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) as efficiently as did ribosomes and S-30 from a spoT+ strain . In both cases, the level of pppGpp reached its maximum before ppGpp maximally accumulated . pppGpp added to the ribosome system was rapidly converted to ppGpp . These results indicate that the spoT+ gene product may not have a direct role in the synthesis of pppGpp and that pppGpp is a precursor of ppGpp.

Biokhimiia, 1977 Dec, 42(12), 2235 - 45
{The alpha-methylglucoside transport in Escherichia coli K12 cells}; Shul'gina MV et al.; The transport of alpha-methylglucoside (MG) in the wild type cells of Escherichia coli K12 and the isogenic mutant strains, defective in the activity of phosphoenolpyruvate: sugar phosphotransferase system components was studied . It was shown that the enzyme IIB' in the absence of enzyme I and HPr is able to transport MG into the cells by a "facilitated" diffusion mechanism . Compounds which dissipate the energy of membrane protone potential such as NaN3, carbonylcyanide-m-chlorophenylhydrasone, dicyclohexylcarbodiimide, enhance the utilization of MG by the wild-type cells . However, the cells retaining intact enzyme IIB' but deficient in the phospho approximately HPr-generating system, were not sensitive to the action of poisons . The cells possessing the intact phospho HPr-generating system and inactive enzyme IIB' are also unaffected by the poisons . It seems that these results do not confirm the hypothesis of the direct delta mu H+ involvement in the regulation of transmembrane phosphorylation . The hypothesis is postulated that the energy metabolism inhibitors influence the phosphatase activity of factor III of the phosphotransferase system . The present data are well explained by this hypothesis.

Appl Environ Microbiol, 1977 Dec, 34(6), 751 - 5
Macromolecule synthesis of Escherichia coli BB at a lower or transient growth state; Sawada T et al.; Macromolecule synthesis in Escherichia coli BB at lower growth rates was investigated . The results indicate that a deviation in ribonucleic acid (RNA) content per cell at a lower growth rate from the exponential relationship to a specific growth rate is entirely attributable to the presence of nonviable cells, in which the RNA content is lower than in viable cells . Based on this fact, a mathematical expression of macromolecule contents versus specific growth rate was devised . Moreover, continuous changes in macromolecule content during unbalanced growth from late-logarithmic phase to stationary phase were measured . Although growth rates changed continuously, the data on deoxyribonucleic acid (DNA) or RNA content versus the specific growth rate calculated from the increments in cell number satisfactorily fitted the exponential lines obtained under balanced growth at a higher growth rate . However, no such relationship was observed in the plot of DNA or RNA content versus the specific growth rate calculated from the increments in optical density.

Appl Environ Microbiol, 1977 Dec, 34(6), 720 - 4
Performance characteristics of a new photometer with a moving filter tape for luminescence assay; Picciolo GL et al.; The performance characteristics of a new photometer that incorporated a reaction system consisting of a movable filtration tape have been studied for use with the firefly luciferase assay for adenosine 5'-triphosphate . Precision, linearity, and sensitivity are given for measuring a graded series of constant-light emitters, concentrations of adenosine 5'-triphosphate, and washed bacterial cells . Precision ranged from 1 to 10% coefficient of variation . The coefficient of correlation was 0.9985 for 7 X 10(8) to 7 X 10(3) bacteria per ml; however, the accuracy decreased at the low levels . The sample processing time was 2 min for a 1-ml sample . This instrument shows potential for many applications in quantitating small numbers of organisms, e.g., pollution, water monitoring, and clinical infection detection.

J Cell Physiol, 1977 Dec, 93(3), 345 - 52
Inhibition of mammalian ribonucleotide reductase by a dinucleotide produced in eucaryotic cells; Lewis WH et al.; HS3, a highly phosphorylated dinucleoside originally purified from the fungus Achlya, has been isolated from Chinese hamster ovary cells undergoing glutamine starvation . The HS3 compounds obtained from the fungal and mammalian sources exhibited similar physical and chemical properties . This unusual dinucleotide may be an important regulator of eucaryotic ribonucleoside diphosphate reductase activity; for 50 micrometer HS3, isolated from either mammalian or fungal cells, significantly inhibited CDP reduction in Achlya or hamster cell preparations, but only marginally affected the activity of the enzyme from E . coli . Studies with HS3 isolated from Achlya and partially purified mammalian ribonucleotide reductase indicated that the compound noncompetitively inhibited the reduction of varying concentrations of the substrates CDP, ADP and GDP with Ki values of 23 micrometer, 14 micron and 16 micron respectively . These inhibitor concentrations are well below the estimated intracellular levels of HS3 in glutamine starved cells and suggest that HS3 inhibition of ribonucleotide reduction may be responsible for the rapid inhibition of DNA synthesis seen under these culture conditions.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Dec, 32(6), 513 - 21
The influence of membrane lipid composition and procaine on hyperthermic death of cells; Yatvin MB; The mechanism of hyperthermic killing, a component of some cancer therapy, is not known . Cell-survival curves during hyperthermic exposure can be used to elucidate the effects of membrane modifying procedures on cell death . Experiments were designed to test whether procedures that were reported to increase membrane fluidity also resulted in increased killing on hyperthermic exposure . An E . coli K12 mutant, K1060, is used to predictably alter the degree and amount of unsaturated fatty acids incorporated into membranes . Changing from an 18:1 to an 18:3 unsaturated fatty acid increases killing . Decreasing the amount of unsaturated fatty acid cells incorporated by increasing growth temperature decreases killing . Procaine, a drug known to decrease membrane viscosity, increases heat killing . These data are most simply explained by the hypothesis that membrane disorganization occurs as a result of temperature increasing to a point where a lipid transition causes a membrane structural change, which results in cell-death.

Infect Immun, 1977 Dec, 18(3), 775 - 9
Vero response to a cytotoxin of Escherichia coli; Konowalchuk J et al.; A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E . coli . It was cytotoxic for Vero but not for Y-1 or CHO cells, and its effect on Vero was distinctly different from that of heat-labile enterotoxin . It was labile to heat and antigenically different from heat-labile enterotoxin, and membrane filtration indicated a molecular weight of 10,000 to 30,000.

J Urol, 1977 Dec, 118(6), 916 - 8
Emphysematous pyelonephritis; Lee SE et al.; We herein describe 2 cases of emphysematous pyelonephritis, which can be added to the 42 cases previously reported . Both female patients were diabetic and had Escherichia coli infections . Both had ureteral obstruction and underwent nephrectomy to survive septic and/or azotemic crises . Timely surgical intervention after unsuccessful antibiotics and conventional medical measurements is life-saving.

J Pediatr, 1977 Dec, 91(6), 897 - 900
Alterations of lymphocytes and of antibody content of human milk after processing; Liebhaber M et al.; The effects of pasteurization, lyophilization, and freezing on immunoglobulin and lymphocytes in human milk was studied . We found a significant decrease in total lymphocyte count after all three processing methods . Pasteurization and lyophilization caused a significant decrease in immunoglobulin concentration and in specific antibody titer to Escherichi coli . Freezing specimens up to four weeks resulted in no significant alteration of IgA content or in E . coli antibody titer . Since a major advantage of human milk is the transference of passive local immunity, these quantitative changes may have clinical importance.

J Hyg (Lond), 1977 Dec, 79(3), 395 - 403
Serotype-related enterotoxigenicity in Escherichia coli O6.H16 and O148.H28; Scotland SM et al.; The ability of certain Escherichia coli strains to produce enterotoxin is determined by transmissible plasmids . It is therefore possible that any E . coli strain might be able to acquire such a plasmid and that the correlation between enterotoxigenicity and serotype might be random . However, recent studies show that the enterotoxigenic strains so far describe belong to a restricted range of serotypes . Enterotoxigenic strains of E . coli O6.H16 and E . coli O148.H28 have been associated with outbreaks of diarrhoea in several countries, therefor strains of E . coli belonging to these serotypes were selected for further study . Twenty-three strains of E . coli O6.H16 and 14 strains of E . coli O148.H28 were examined; 20 strains of E . coli O6.H16 and all 14 strains of E . coli O148.H28 were enterotoxigenic but strains of E . coli O6 wit flagellar antigens other than H16 and strains of E . coli O148 wit flagellar antigens other than H28 were not enterotoxigenic . The examination of single colony subcultures derived from the E . coli O6.H16 strains showed that in some strains loss of enterotoxigenicity had occurred in a proportional of colonies.

J Bacteriol, 1977 Dec, 132(3), 996 - 1002
Synthesis of mot and che gene products of Escherichia coli programmed by hybrid ColE1 plasmids in minicells; Matsumura P et al.; Hybrid Escherichia coli ColE1 plasmids carrying the genes for motility (mot) and chemotaxis (che) were transferred to a minicell-producing strain . The mot and che genes on the hybrid plasmid directed protein synthesis in minicells . Polypeptides synthesized in minicells were identical to the products of the motA, motB, cheA, cheW, cheM, cheX, cheB, cheY, and cheZ genes previously identified by using hybrid lambda and ultraviolet-irradiated host cells (Silverman and Simon, J . Bacteriol . 130:1317-1325, 1977), thus confirming these gene product assignments . The products of some che genes (cheA and cheM) appeared as more than one band on polyacrylamide gel electrophoresis, but analysis of partial peptide digests of these polypeptides suggested that the multiple forms were coded for by a single gene . Measurement of the physical length of the hybrid plasmids allowed an estimate of the amount of coding capacity of the cloned deoxyribonucleic acid, which was devoted to the synthesis of the mot and che gene products . These estimates were also consistent with the hypothesis that the multiple polypeptides corresponding to cheA and cheM were the products of single genes.

J Bacteriol, 1977 Dec, 132(3), 931 - 49
Characterization of hybrid plasmids carrying individual ribosomal ribonucleic acid transcription units of Escherichia coli; Kenerley ME et al.; We have screened the strains with ColE1 hybrid plasmids constructed by Clarke and Carbon (Cell 9:91-99, 1976) for the presence of ribosomal ribonucleic acid (rRNA) genes on the plasmids and identified 16 strains whose plasmids carry rRNA genes . The structures of these 16 plasmids were compared by heteroduplex analysis, and the plasmids were classified into six groups on the basis of their chromosomal origins . Homology with known transducing-phage deoxyribonucleic acids and genetic mapping have assigned locations on the Escherichia coli chromosome to three of the six groups . These are rrnB near rif at 88 min, rrnC near ilvE at 83 min, and rrnD near aroE at 71 min . A fourth group is probably rrnA at 85 min (T . Ikemura and M . Nomura, Cell, 11:779-793, 1977) . We conclude that the minimum number of rRNA transcription units per haploid chromosomes is seven, that is, the six groups identified in this work plus a known operon (rrnE near metA at 89 min) that we failed to find among the hybrid plasmids . This heteroduplex analysis also suggests that there are only two kinds of rRNA operons with respect to their spacer region; three of the six rRNA operon groups studied here have one kind, whereas the remaining three have the other kind.

J Bacteriol, 1977 Dec, 132(3), 904 - 11
Genetic analysis of the Escherichia coli K-12 srl region; McEntee K; Specialized transducing lambda derivatives, deletion mapping, and Plkc transductional crosses have been used to analyze the genetic organization and regulation of the srl genes . Transducing phages obtained from a secondary site lambda insertion in srlA are of two types: lambdapsrlC1 and lambdaprecA are substituted in the b2 region of the lambda chromosome (galtype) and carry the srlC gene but not srlD; lambdapsrlD is substituted in the early region of the phage deoxyribonucleic acid (biotype) and carries the srlD gene but not srlC . The lambdapsrlC1 phage, which lysogenizes at attlambda, complements srlC mutants in trans, indicating that this gene codes for a diffusable positive regulatory element . The srl genes have been ordered relative to the cysC, recA, and alaS genes by two- and three-factor P1kc crosses . The order, cysC...srlD-srlA-srlC-recA-alaS, has been obtained . The srlA and srlD genes comprise an operon with srlD operator distal . From the secondary site lysogen, it has been possible to obtain deletion mutants of this region that are sensitive to ultraviolet light and are recombination deficient . Genetic evidence suggests that these deletions extend from srl into the recA gene.

J Bacteriol, 1977 Dec, 132(3), 870 - 5
Characterization of fusions between the lac operon and the ilv gene cluster in Escherichia coli: ilvC-lac fusions; Smith JM et al.; By means of the general procedure of Casadaban (J . Mol . Biol . 104: 541-556, 1976), the lac genes carried on a lambda-Mu-1 hybrid phage were inserted into a temperature-inducible Mu-1 prophage that had earlier been inserted into a site near the beginning of the ilvC gene of Escherichia coli strain K-12 . Selection of temperature-resistant derivatives of the lysogen resulted in a fusion of the lac genes to a region of deoxyribonucleic acid that is transcribed under the control of the ilvC regulatory elements . A strain bearing the fusion was shown to be inducible for beta-galactosidase by acetohydroxybutyrate, a natural inducer of acetohydroxy acid isomeroreductase . Induction of the lysogen by mitomycin C led to the isolation of a plaque-forming lambda derivative carrying this ilvC-lac fusion.

J Bacteriol, 1977 Dec, 132(3), 832 - 40
Isolation of a metK mutant with a temperature-sensitive S-adenosylmethionine synthetase; Hafner EW et al.; An Escherichia coli metK mutant, designated metK110, was isolated among spontaneous ethionine-resistant organisms selected at 42 degrees C . The S-adenosylmethionine synthetase activity of this mutant was present at lower levels than in the corresponding wild-type strain and was more labile than the wild-type enzyme when heated or dialyzed . A mixture of mutant and wild-type enzyme preparations had an activity equal to the sum of the component activities . These facts strongly suggest that the mutated gene in this strain is the structural gene for this enzyme . Genetic mapping experiments placed the metK110 mutation near or at the site of other known metK mutants (i.e., 63 min), confirming its designation as a metK mutant . A revised gene order has been established for this region, i.e., metC glc speC metK speB serA.

J Bacteriol, 1977 Dec, 132(3), 784 - 9
Genetic mapping of the F plasmid gene that promotes degradation of stable ribonucleic acid in Escherichia coli; Ohnishi Y et al.; F+ Escherichi coli cells that contain an srnA mutant allele degrade their stable ribonucleic acid (RNA) extensively after RNA synthesis is blocked at 42 degrees C . The relevant gene promoting degradation of stable RNA, srnB+, or its promoter was mapped between 1.7 and 2.8 kilobases on the F plasmid by using deleted F' plasmids and chimeric plasmids composed of pSC101 and fragments of F plasmid.

J Bacteriol, 1977 Dec, 132(3), 779 - 83
Thymineless death in Escherichia coli dnaB mutants and in a dnaB dnaG double mutant; Sicard N et al.; The interference of dnaB mutations of Escherichia coli with thymineless death is described . All the isogenic Thy- dnaB mutants of E . coli we have tested show a remarkable immunity towards cell death induced by thymine deprivation at the nonpermissive temperature . We have also constructed and tested an isogenic double dnaB dnaG mutant . It loses its viability in the absence of thymine at both permissive and nonpermissive temperatures . The role of the dnaB gene product is discussed.

J Bacteriol, 1977 Dec, 132(3), 1038 - 41
Formation of HfrH-type donor cells as a result of integrative suppression by R-F recombinant plasmids; Horodniceanu T et al.; Three recombinant plasmids, resulting from recombination between an R plasmid of the FI incompatibility group and the F of HfrH, were introduced in a temperature-sensitive dnaA mutant to isolate Hfr-type-donors . All of the temperature-insensitive clones isolated from two of the three recombinant plasmids had the same origin and transfer pattern as the parental HfrH strain.

J Bacteriol, 1977 Dec, 132(3), 1034 - 5
Anaerobic electron transport in anaerobic flagellum formation in Escherichia coli; Hertz R et al.; Flagellum formation by ubiquinone- and menaquinone-deficient mutant strains of Escherichia coli K-12 was studied under both aerobic and anaerobic growth conditions . Ubiquinone was found to be obligatory for aerobic flagellum formation but could be replaced by menaquinone for anaerobic flagellum formation . A mutant devoid of both quinones was immotile aerobically as well as anaerobically . Hence, the respective electron transport system is obligatory for flagellum formation in Escherichia coli.

J Bacteriol, 1977 Dec, 132(3), 1021 - 3
Effects of a protease inhibitor on biosynthesis of Escherichia coli proteins; Ito K; A protease inhibitor, tosyl-L-lysine chloromethylketone, altered the composition of newly synthesized protein in Escherichia coli; a significant portion of the proteins synthesized sedimented rapidly, presumably forming aggregates of the abnormal proteins . Protein I of the outer membrane was only slightly synthesized under these conditions.

J Clin Invest, 1977 Dec, 60(6), 1280 - 8
Chemotactic factor inactivators of human granulocytes; Brozna JP et al.; During phagocytosis, neutrophils release a variety of substances that include activators and inactivators of chemotactic factors . It is generally considered that these represent hydrolytic enzymes . Elastase and cathepsin G, major proteases released from lysosomal granules during phagocytosis, contain broad hydrolytic activity . This study examined granule elastase and cathepsin G for their role as inactivators of chemotactic factors . Elastase and cathepsin G were purified from human neutrophils by Trasylol-Sepharose and CM-cellulose chromatography . Small amounts (approximately equal to 3 microgram, 1 muM) of elastase and cathepsin G, comparable to quantities released by 10(6) neutrophils during phagocytosis, completely inactivated the C5 chemotactic factor generated in human serum . Larger concentrations were needed to inactivate the C3 chemotactic factor, and when the bacterial chemotactic factor from Escherichia coli was employed, five times more elastase or cathepsin G was ineffective against this chemotactic factor . Supernatant fluid from human neutrophils that had ingested complement-coated zymosan particles contained elastase and cathepsin G and had inactivator activity for both the C5 chemotactic fragment and the bacterial factor . A specific inhibitor of elastase largely abolished the inactivator activity in the phagocytic supernates that was directed against C5 factor but did not affect the inactivator activity for the bacterial factor . Similar results occurred in studies of granule lysates . These data indicate heterogeneity in the chemotactic factor inactivator activity released by phagocytosing neutrophils . The predominant inactivator activity of the C5 chemotactic fragment is attributable to elastase and cathepsin G.

J Immunol, 1977 Dec, 119(6), 1879 - 81
Cellular events in tolerance . VI . Neonatal vs adult B cell tolerance: differences in antigen-binding cell patterns and lipopolysaccharide stimulation; Venkataraman M et al.; The numbers and fate of antigen-binding cells (ABC) in neonatal and adult mice rendered tolerant to fluorescein (FL)-labeled heterologous gamma-globulins were studied . Similar numbers of FL-ABC were observed 1 day after tolerogen in both adult and neonatal mouse spleens: by 7 days after tolerization, no FL-ABC were observed in either case . Reinjection with FL-tolerogen at 7 days led to the detection of normal numbers of ABC in adult mice but significantly reduced numbers in neonates . This suggests that neonatal ABC either have been deleted or have failed to resynthesize surface receptors . Two weeks after tolerance induction, spleen cells from these tolerant mice were cultured with Escherichia coli lipopolysaccharide (LPS), a polyclonal B cell mitogen, or with specific antigen . Tolerant adult spleen cells made an equivalent anti-FL response to that of the uninjected controls when stimulated with LPS, but were unresponsive to specific antigenic triggering . In contrast, spleen cells from neonatally tolerized mice were unresponsive to either specific or nonspecific (LPS) stimulation . Thus, these neonatally tolerized spleen cells lose sensitivity to polyclonal-stimulating agents (along with their receptors), or more simply, are deleted.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5305 - 9
Phage T4-modified RNA polymerase transcribes T4 late genes in vitro; Rabussay D et al.; Initiation of T4 late RNA synthesis has been achieved in an in vitro system prepared from Escherichia coli cells infected with wild-type or maturation-defective mutant T4 phage . The system uses a cellophane membrane as a mechanical support for concentrated cell lysates and for added streptolydigin-resistant RNA polymerases . Transcriptional activity and selectivity of added RNA polymerases are tested while endogenous RNA polymerase activity is inhibited by streptolydigin . T4-modified RNA polymerase is required for substantial stimulation of T4 late RNA synthesis.

J Hyg (Lond), 1977 Dec, 79(3), 315 - 9
A test for the assessment of disinfectant/sanitizers used for napkin storage; Prosser-Snelling KR et al.; A test is described for assessing the effect of hypochlorites in reducing the bacterial load on soiled napkins during storage, between removal from the infant and laundering.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5551 - 3
31P nuclear magnetic resonance measurements of ATPase kinetics in aerobic Escherichia coli cells; Brown TR et al.; We have measured the in vivo unidirectional rates between the terminal phosphate of ATP and intracellular inorganic phosphate (PiIN) in aerobic suspensions of Escherichia coli cells using 31P nuclear magnetic resonance saturation transfer techniques . Typically, the measurements consisted of saturating the ATPgamma resonance and observing a 20 +/- 5% reduction in the intensity of the PiIN resonance . No saturation transfer was observed after incubation with 1 mM dicyclohexylcarbodiimide, an ATPase inhibitor . From the measured decrease in intensity of PiIN coming from saturation transfer, the apparent unimolecular rate constant of PiIN to ATP was calculated to be 0.6 +/- 0.15 sec-1.

Proc Natl Acad Sci U S A, 1977 Dec, 74(12), 5637 - 41
A pH-conditional mutant of Escherichia coli; Colb M et al.; Mutants of Escherichia coli have been isolated that are able to grow on lactose at pH 7.0 but not at pH 8.1 . One of these mutants was analyzed and shown to map in the Z region of the lactose operon . beta-Galactosidase (beta-D-galactoside galactohydrolase; EC 3.2.1.23) activity in toluenized mutant cells at pH 8.0 was one-tenth that at pH 7.0 . Enzyme purified to near homogeneity from the pH-conditional mutant similarly exhibited pH-conditional activity under conditions where wild-type enzyme was unaffected over a pH range of 6.0-8.0 . The pH-conditional beta-galactosidase was used in vivo as a probe for intracellular pH . We show that an internal pH of approximately 7.8-8.0 is maintained through an external pH range of 5.9-7.8 . The phenotype of pH-conditional mutants was defined on medium with lactose as the sole carbon source . Under such conditions the gene product itself, beta-galactosidase, is required to maintain intracellular pH, since such maintenance is clearly energy-dependent . Therefore, we were able to recover a pH-conditional mutant in a cytoplasmic gene product . We predict that with any phenotype independent of energy production, however, pH-sensitive mutants will be recovered only in surface elements.

Can J Biochem, 1977 Dec, 55(12), 1228 - 32
Further studies on the cardiolipin phosphodiesterase of Escherichia coli; Cole R et al.; The cardiolipin phosphodiesterase of Escherichia coli was further characterized . This enzyme has a pH optimum of 7.0 and is Mg2+ dependent . Mn2+ and Co2+ could replace Mg2+ but other divalent cations were inhibitory or without effect . The enzyme is not periplasmic and does not appear to be associated with membrane fractions prepared by different methods . It is recovered as a soluble protein in the cytosol fraction but could not be readily purified because of its instability . With cell-free systems, a requirement for ATP or ADP could be shown under certain defined conditions . Other nucleotides were less effective or ineffective in stimulating the phosphodiesterase . The cells displayed the highest activity during the middle to late exponential stage but no marked requirement for ATP was apparent when the phosphodiesterase was obtained from such freshly grown cells . If, however, cells were starved for several hours in saline medium, the cardiolipin phosphodiesterase level fell and a requirement for added ATP could be shown . The cardiolipin phosphodiesterase is an enzyme distinct from cardiolipin synthase . The assay conditions are quite different from each of these enzymes as are their subcellular distributions.

Mol Gen Genet, 1977 Nov 29, 157(2), 205 - 14
Exchange of ribosomal proteins among the ribosomes of Escherichia coli; Robertson WR et al.; The exchange of ribosomal proteins among ribosomes of E . coli has been measured, using a density label technique . As expected most of the proteins do not exchange appreciably . However a substantial fraction of each of proteins S1, S2, S21, L7/L12, L9, L10, L11, L26 and L33 is found to exchange, but exchange of S1, S2, L7/L12, L10, L11 and L26 is found to occur in vitro after lysis of the cells, and therefore it is not possible to say whether or not these proteins also exchange in vivo . tin contrast S21, l9 and L33 do not exchange after lysis of the cells and we therefore conclude that these proteins exchange in vivo . The maximum level of exchange of S21, L9 and L33 is attained so rapidly that we were unable to show whether or not it was dependent on protein synthesis.

Mol Gen Genet, 1977 Nov 29, 157(2), 149 - 53
Amber mutations in Escherichia coli essential genes: isolation of mutants affected in the ribosomes; Delcuve G et al.; A method to obtain amber mutations in ribosomal protein genes is described . tit relies on the P1-mediated localized mutagenesis (Hong and Ames, 1971) and on the fact that the recipient strain contains (a) an efficient but genetically unstable suppressor, (b) a particular thermoinducible lambda prophage which kills suppressor hosts at 42 degrees C . Exposure of these bacteria to the high temperature yields frequent suppressor-free derivatives while none will be found if the strain carries an amber mutation in an essential gene . Eleven mutants have been isolated by this method, of which at least six appear to carry amber mutations . All of them map close to, and to the right of spcA, in a region which codes mostly for ribosomal proteins . Three mutants were studied biochemically; all three show defective ribosomal assembly in vivo upon loss of suppression.

Mol Gen Genet, 1977 Nov 29, 157(2), 119 - 29
Transposition and insertion of intact, deleted and enlarged ampicillin transposon Tn3 from mini-R1 (Rsc) plasmids into transfer factors; Goebel W et al.; The miniR1-(Rsc)-plasmids which derive from the copy mutant R1drd-19B2 (pKN102) are non-conjugative extrachromosomal elements which can not be co-transferred by various transfer factors to recipient strains under standard mating conditions . The attempts to mobilize Rsc11 by F'lac lead to transconjugants carrying F'lac::Tn3 with Tn3 mainly inserted into the lac operon . In addition it can be shown that Rsc11 can become inserted as a complete unit into the transfer factor giving rise to rather unstable recombinant intermediates . Dissociation of these intermediates may lead to alterations of the original plasmids . The Tn3 part of Rsc13 can be enlarged or deleted by in vitro manipulations . In vitro insertion of EcoRI-fragments into an EcoRI+ site of Tn3 leads to new transposable units which can be transposed to the RTF part of R1 . This new genetic entity can be stably integrated into the chromosome of E . coli by integrative suppression of a dnaAts-mutation . Deletions at one end or the central region of Tn3 abolish the capability of transposition . However, the Rsc-plasmids containing the deleted Tn3 can still be inserted into the transfer factor as complete units . The resulting recombinants are unstable leading after dissociation in some cases to new plasmids with altered properties.

Mol Gen Genet, 1977 Nov 29, 157(1), 91 - 7
Genetic mapping of the lexC-113 mutation; Johnson BF; A mutation, previously designated lex-113 and suspected to be situated in the lexA locus, has been positioned by transductional studies to a unique site on the chromosome of E . coli B separate from the lexA102 and uvrA155 mutations . The order of genes in this chromosomal region was demonstrated to be malB-lexA-uvrA-lex-113 . The allele designation lexC-113 is suggested for this mutation in a new gene functional in the regulation of inducible lex+ - and rec+-dependent SOS activities.

Mol Gen Genet, 1977 Nov 29, 157(1), 83 - 9
The genetic characterization of lexB32, lexB33 and lexB35 mutations of Escherichia coli: location and complementation pattern for UV resistance; Glickman W et al.; Mutants of LexB have been isolated by their resistance to lysogenic induction by thymine starvation, their resistance to thymine starvation and on the basis of their UV sensitivity . Here, three mutations identified originally in strains lacking mutagenic response to UV-irradiation, unmB (Kato and Shinoura, 1977), have been further characterized, mapped by P1-mediated transduction with srl into the recA-tif-zab-lexB cluster at the lexB position and analysed for complementation with various lexB and recA mutations . From the results it was concluded that unmB mutations are identical to lexB mutations; consequently these mutations have been termed lexB32, lexB33 and lexB35 . The mutations lexB33 and lexB35 do not complement any of the other lexB mutations and define therefore a new complementation type . The lexB32 mutation, which like the lexB34 mutation, results in moderate UV sensitivity has a complementation pattern similar to that of lexB34 . However, unlike lexB34 the lexB32 behaves like a leaky mutation . The results are discussed in relation to the recA gene product and its control.

Mol Gen Genet, 1977 Nov 29, 157(1), 17 - 23
Mapping of the drug resistance genes carried by the r-determinant of the R100.1 plasmid; Lane D et al.; We have cloned the EcoRI fragments of pLC1, a circular DNA element found in an Escherichia coli dnaAts strain integratively suppressed by R100.1 (Chandler et al., 1977a), using the plasmid vector pCR1 . All the resistance genes known to be present on the r-determinant of R100.1 were found to be present on pLC1 . The isolation of pCR1 derivatives carrying various EcoRI fragments of either pLC1 or R100.1 has allowed a more precise mapping of the position of the resistance genes on the R100.1 molecule.

Mol Gen Genet, 1977 Nov 29, 157(1), 109 - 18
Genetic analysis of mutations in the transfer genes of pDU202 tra::Tn10 plasmids, caused by the excision of Tn10; Kehoe MA et al.; Transfer-deficient derivatives of pDU202 (a Tcs deletion mutant of R100-1) caused by the insertion of Tn10 into the R factor's transfer genes have been described previously . Tetracyline-sensitive mutants of four of these were selected . In the majority of cases the Tcs mutation was caused by a deletion of the Tcr genes which was often accompanied either by a deletion of some of the flanking transfer genes or by a secondary mutation which was probably an inversion . A number of preferred end points for the deletions and inversions occur in the transfer operon of pDU202 . Analysis of the mutants by complementation tests with Flac tra elements confirmed that the order of genes in the promoter distal part of the tra region of pDU202 is traKBCFHGSD and traI.

Vet Rec, 1977 Nov 26, 101(22), 443 - 6
Studies on the immunity of the calf to colibacillosis--VII: the experimental reproduction of enteric colibacillosis in colostrum-fed calves; Logan EF et al.; Eight newborn calves were challenged orally with a known enteropathogenic strain of Escherichia coli 0101 K?(A) and two to six hours later each calf was fed a minimum of three pints colostrum . All calves suffered from acute diarrhoea of varying severity within 24 to 48 hours of infection . Immunofluorescent and histological examination of the small intestine demonstrated adherence of the challenge organism to the epithelium and the presence of pathological lesions similar to those seen in colostrum-deprived calves with enteric colibacillosis . It was concluded that in order to be effective prophylactically, colostrum must be fed prior to infection.

J Biol Chem, 1977 Nov 25, 252(22), 8136 - 41
Asymmetry of binding and physical assignments of CTP and ATP sites in aspartate transcarbamoylase; Suter P et al.; The allosteric effectors of aspartate transcarbamoylase from Escherichia coli, CTP and ATP, associate with both the regulatory and the catalytic moieties of the enzyme . Studies with isolated, active subunits yield one binding site per regulatory dimer and one per catalytic trimer . Investigations of effector association with hybrid enzymes, containing either the three regulatory dimers or the two catalytic trimers in inactivated forms, indicate that the data obtained with isolated subunits can be used to analyze the binding patterns of these ligands to the native hexamer . Thus, the nonlinear Scatchard plots, characteristic of the binding of CTP and ATP to the native enzyme, can be interpreted in terms of three effector molecules associating with the regulatory subunits, and two binding to the catalytic moiety of the enzyme . Results with native protein in the presence of saturating concentrations of active site ligands support these assignments . The differences between the binding isotherms of CTP and ATP to the enzyme are due to their different affinities to the two types of subunits . The apparent half-of-the-site saturation of the regulatory moiety of aspartate transcarbamoylase supports the concept that this protein has a tendency to exist in an asymmetric state.

J Biol Chem, 1977 Nov 25, 252(22), 8113 - 7
Stereochemistry of the dTDP-glucose oxidoreductase reaction; Snipes CE et al.; The stereochemical course of the dTDP-glucose oxidoreductase (EC 4.2.1.46) reaction was studied using enzyme partially purified from Escherichia coli and dTDP-(6R)- and (6S)-{4-2H, 6-3H}glucose as substrate . The latter was prepared enzymatically by reduction of (3R)- and (3S)-3-P-{3-3H}glycerate to the 1-deuterated 3-P-glyceraldehyde with (4S)-{4-2H}NADH, followed first by conversion to glucose-1-P with the glycolytic enzymes, and then by transformation into the dTDP derivative . The stereospecifically labeled dTDP-glucose samples were mixed with nonlabeled carrier material and converted to dTDP-4-keto-6-deoxyglucose, which contained a chiral methyl group as shown by chirality analysis of the acetic acid resulting from Kuhn-Roth oxidation of the sugar nucleotide . These results confirm that the hydrogen transfer from C4 to C6 is intramolecular and show that the migrating hydrogen replaces the 6-hydroxyl group with inversion of configuration . Assuming that the hydrogen transfer, since it is intramolecular, must be suprafacial, it follows that the elimination of water from C5 and C6 is formally syn, whereas the reduction of the resulting delta5,6-double bond formally involves an anti addition of H+ and H-.

Biochim Biophys Acta, 1977 Nov 16, 479(2), 172 - 9
Physiological studies on a temperature-sensitive Escherichia coli mutant with an altered RNA polymerase beta'-subunit; Yoshinaga K et al.; Some in vivo properties of an Escherichia coli temperature-sensitive mutant (JE10092) with an altered RNA polymerase beta'-subunit are described . RNA synthesis, unlike many peviously isolated temperature-sensitive mutants, stops immediately after the shift to the nonpermissive temperature (43 degrees C) . DNA synthesis, protein synthesis and nucleoside triphosphate formation continue after the shift . RNA synthesis is recovered immediately upon transfer to the permissive temperature (30 degrees C) . The function of the beta'-subunit in genetic transcription is discussed.

Biochim Biophys Acta, 1977 Nov 16, 479(2), 143 - 51
Chemical aminoacylation of transfer ribonucleic acid . The reaction of Escherichia coli tRNA with ethyl N-benzyloxycarbonylorthoglycinate; Hwang JS et al.; The alpha-carbethoxypentadecyltrimethylammonium (Septonex) salt of tRNA (Ib) was condensed with ethyl N-benzyloxycarbonylorthoglycinate (II) in dimethylformamide in vacuo and in the presence of H3PO4 as catalyst . Pancreatic RNAase degradation and phenylalanine acceptor activity showed a 55--60% conversion to the 2',3'-cyclic orthoglycinate derivative of tRNA (IIIb) . The orthoester grouping of IIIb was quantitatively hydrolyzed in 80% formic acid at 0 degrees C for 15 min to give 2'(3')-O-(N-benzyloxycarbonyl)glycyl tRNA (IVb) . The latter was stripped at pH 8.8 to give tRNA whose behavior on DEAE cellulose column and gel electrophoresis was similar to that of starting tRNA . The phenylalanine acceptor activity amounted to almost 80% of the starting tRNA.

Biochem J, 1977 Nov 15, 168(2), 195 - 204
Transport of adenine, hypoxanthine and uracil into Escherichia coli; Burton K; Uptake of adenine, hypoxanthine and uracil by an uncA strain of Escherichia coli is inhibited by uncouplers or when phosphate in the medium is replaced by less than 1 mM-arsenate, indicating a need for both a protonmotive force and phosphorylated metabolites . The rate of uptake of adenine or hypoxanthine was not markedly affected by a genetic deficiency of purine nucleoside phosphorylase . In two mutants with undetected adenine phosphoribosyltransferase, the rate of adenine uptake was about 30% of that in their parent strain, and evidence was obtained to confirm that adenine had then been utilized via purine nucleoside phosphorylase . In a strain deficient in both enzymes adenine uptake was about 1% of that shown by wild-type strains . Uptake of hypoxanthine was similarly limited in a strain lacking purine nucleoside phosphorylase, hypoxanthine phosphoribosyltransferase and guanine phosphoribosyltransferase . Deficiency of uracil phosphoribosyltransferase severely limits uracil uptake, but the defect can be circumvented by addition of inosine, which presumably provides ribose 1-phosphate for reversal of uridine phosphorylase . The results indicate that there are porter systems for adenine, hypoxanthine and uracil dependent on a protonmotive force and facilitated by intracellular metabolism of the free bases.

Eur J Biochem, 1977 Nov 15, 81(1), 79 - 90
Physico-chemical properties of a DNA binding protein: Escherichia coli factor H1; Spassky A et al.; H1 factor is a heat-stable protein found in large amounts in Escherichia coli . In vitro, this protein has been found to stimulate transcription of lambda templates by E . coli DNA-dependent RNA polymerase . The subunit molecular weight of this factor has been re-estimated and found to be 15500 +/- 1000 in the presence of 2-mercaptoethanol . Crosslinking experiments performed with dimethylsuberimidate in the presence or absence of the DNA template indicate the presence of multiples of the 15500-Mr subunit up to the tetramer, the dimeric species being predominant . One cysteinyl residue per 15000-Mr subunit is labeled by 4-chloro-7-nitrobenzofurazan . This residue is not labeled if the factor is exposed to oxidizing conditions . In this case, three lysyl residues are titrated . H1 factor behaves as a DNA-binding protein . We have detected binding to DNA by two independent methods: displacement of a fluorescently labeled factor by the native protein and retention of radioactive DNA on millipore filters in the presence of the factor . Under our experimental conditions (high ionic strength, absence of magnesium ions), the saturation function of lambda plac DNA as well as of wild-type lambda DNA has been found to be non-cooperative . Saturation is reached when 300 +/- 30 molecules of dimeric factor are bound per lambda molecule, the average dissociation constant of the complex being 10nM . The dissociation time of the H1.DNA complex is less than 5 s at 37 degrees C . The binding of this factor lowers the affinity of native DNA for ethidium bromide . In the presence of this intercalating dye, the solubility of the complex decreases drastically.

Eur J Biochem, 1977 Nov 15, 81(1), 205 - 10
Enzymes synthesizing and hydrolyzing murein in Escherichia coli . Topographical distribution over the cell envelope; Goodell EW et al.; Envelopes from regions of the cell which in vivo show very little, if any, murein synthesis were isolated using the minicell-producing strain P678-54 . Envelopes from minicells, representing in fact cell ends, were able to synthesize murein and to carry out transpeptidation in vitro; also all four murein hydrolase activities tested, carboxypeptidase, endopeptidase, amidase and transglycosylase, were found to be present . The specific activities of the murein synthesizing and degrading enzymes in envelopes derived from cell poles and from actively growing cells were similar . The topological distribution of murein-synthesizing enzymes and of murein hydrolases over the cell envelope is discussed.

Eur J Biochem, 1977 Nov 15, 81(1), 179 - 83
{Lipopolysaccharides from thermosensitive mutants of Escherichia coli K12 (author's transl)}; Bruneteau M et al.; Thermosensitive mutants of Escherichia coli K12 were grown at 30 degrees C and 40 degrees C . The serologic properties and the composition of their lipopolysaccharides were investigated . The inhibition of hemagglutination by the lipopolysaccharides of various mutant strains was tested against the anti-E . coli K12 CR34 system . An inhibition was observed with all the mutants but one, CR34 T83 which had no inhibitory effect . Chemical analysis of lipopolysaccharides and mass spectrometric analysis of their methylated derivatives indicated the presence of the same components in the various lipopolysaccharides: glucose, galactopyranose, galactofuranose, heptopyranose and heptofuranose . However the 2,3,4 tri-O-methyl glucose is missing in the lipopolysaccharide of the mutant T83 . This result agrees with the absence of a substituent on the 6-position of the non-reducing core-terminal glucose . The lipopolysaccharide of the T83 mutant has the complete core-type of E . coli K12 . The relations of mutations with modifications of the composition of inner and outer envelopes in various mutants are discussed.

Biochemistry, 1977 Nov 15, 16(23), 5135 - 45
Analysis of in vitro transcription of duck reticulocyte chromatin using mercury-substituted ribonucleoside triphosphates; Zasloff M et al.; We have employed mercury-substituted UTP to study the transcription of duck reticulocyte chromatin in vitro by Escherichia coli RNA polymerase . We find that the use of this method results in large overestimates of the amount of de novo synthesis of globin-specific RNA sequences . The artefact arises because endogenous globin RNA can serve as a template for the RNA polymerase, resulting in the formation of a duplex product in which one strand is the endogenous message, and the other is the mercury-labeled complementary strand . Subsequent purification of the mercury-substituted RNA on thiol-agarose results in copurification of endogenous globin sequences . We document the details of this mechanism and describe methods which will eliminate the artefact.

Biochemistry, 1977 Nov 15, 16(23), 5120 - 6
3'-Phosphatase activity in T4 polynucleotide kinase; Cameron V et al.; The purification of T4 polynucleotide kinase results in the copurification of an activity which will specifically remove the 3'-terminal phosphate from a variety of deoxyribonucleotides and ribonucleotides in the absence of ATP . This phosphatase activity requires magnesium, has a pH optiumum of 6.0, and is more active with deoxyribonucleotides than ribonucleotides . T4 polynucleotide kinase and the 3'-phosphatase activity copurify by gradient elution column chromatography on DEAE-cellulose, phosphocellulose, and hydroxylapatite . The two activities are included in and comigrate on Sephadex G-200 . Polyacrylamide gel electrophoresis at PH 9.2 results in conigration of the two activities together with the major protein band . The two activities respond in parallel to heat inactivation at 35 degrees C and ATP, a substrate for the kinase only, protects both activities from heat inactivation . It is therefore suggested that the two activities are functions of the same protein molecule.

Biochem J, 1977 Nov 15, 168(2), 211 - 21
Evidence for an electrogenic 3-deoxy-2-oxo-D-gluconate--proton co-transport driven by the protonmotive force in Escherichia coli K12; Lagarde A; Evidence is presented indicating that the carrier-mediated uptake of 3-deoxy-2-oxo-D-gluconate and D-glucuronate in Escherichia coli K12 is driven by the deltapH and deltapsi components of the protonmotive force . 1 . Approximately two protons enter the cells with each sugar molecule, independent of the sugar and the strain used . 2 . In respiring cells, the magnitude of the pH gradient alone, as measured by distribution of {3H}acetate, appears to be insufficient to account for the chemical gradient of 3-deoxy-2-oxo-D-gluconate that is developed between pH 6.0 and 8.0 . 3 . If the external pH is varied between 5.5 and 8.0, 3-deoxy-2-oxo-D-gluconate uptake is gradually inhibited by valinomycin plus K+ ions, whereas the inhibition caused by nigericin is concomitantly relieved, thus reflecting the relative contribution of deltapH and deltapsi to the total protonmotive force at each external pH . 4 . 3-Deoxy-2-oxo-D-gluconate can be transiently accumulated into isolated membrane vesicles in response to an artificially induced pH gradient . The process is stimulated when the membrane potential is collapsed by valinomycin in the presence of K+ ions.

Biochim Biophys Acta, 1977 Nov 15, 471(1), 125 - 34
Counter-transport mediated by the lactose permease of Escherichia coli; Bentaboulet M et al.; When the two main energy yielding pathways, respiration and the membrane ATPase of Escherichia coli are poisoned, the lactose permease is unable to accomplish accumulative transport of thiogalactosides, but the efflux of preloaded substrate can be coupled to a transiently uphill transport of exogenous substrate . This transient uphill transport, called overshoot has been reexamined with the possibility of an obligate H+ cotransport in mind . Overshoot can be diminished but not suppressed by a proton-conducting uncoupler, carbonyl cyanide m chlorophenylhydrazone, (CCCP) and by a liposoluble cation, triphenyl-methyl phosphonium (TPMP+) . The effect of other factors, such as temperature, amount of permease and pH were also explored . The overshoot was found to decrease with increasing pH, until at pH 8 it became negligible . This is in sharp contrast with the relatively flat pH dependence of uphill and downhill transport in unpoisoned cells . CCCP and TPMP+ had no inhibitory effect on the overshoot at pH 6 and below.

Mol Gen Genet, 1977 Nov 14, 156(2), 229 - 32
Unusual stability and translation kinetics of an Escherichia coli lac messenger RNA synthetized during amino-acids deprivation; Sanchez de Rivas C et al.; Escherichia coli, cultured on minimal medium and deprived of its required amino-acids, was induced for lac genes transcription . After inducer removal and restoration of growth, beta-galactosidase synthesis was measured . Two different kinetics of enzyme synthesis were observed depending on the starvation conditions employed during the induction period: 1 . beta-galactosidase synthesis was immediately obtained and a plateau was reached, in 20 min after restoration of growth, when cells had been induced during deprivation of amino-acids and carbon source . 2 . beta-galactosidase displayed an unusually long rate of synthesis, and plateau was not reached before two doubling times, when cells had been induced during the deprivation of the sole amino-acids . The latter result points out a problem of messenger stability during those long translation kinetics and led us to study the behaviour of strains carrying lac genetic determinants on different replicative structures; chromosomic and plasmidic . In those two situations, induction of lac messenger RNA was obtained and ratify our previous observations . However, their translation kinetics suggest a DNA linkage of this induced messenger.

Mol Gen Genet, 1977 Nov 14, 156(2), 221 - 7
Suppression of a defective alanyl-tRNA synthetase in Escherichia coli: a compensatory mutation to high alanine affinity; Theall G et al.; Among temperature resistant revertants of a temperature sensitive E . Coli alanyl-tRNA synthetase mutant a strain was found which contains an alanyl-tRNA synthetase with an additional mutation in the structural gene of the enzyme . This mutant enzyme has a 9 or 38 fold decreased Km value for alanine compared to that of the thermolabile parental enzyme or to wild-type enzyme, respectively . The alaS gene maps just counterclockwise from recA on the E . coli map (94% cotransduction frequency) . It appears that the enzyme's increased affinity for alanine is the mechanism of suppressing the temperature sensitive character of the cell . In addition, some cold-sensitive temperature resistant revertants were found, where the cold-sensitive character mapped near strA . Presumably they are due to changes in ribosomal proteins as characterized by Ruffler et al . (1974).

Mol Gen Genet, 1977 Nov 14, 156(2), 195 - 201
Purification and some properties of presumptive tof gene product of Coli phage 434; Aono J et al.; The presumptive tof gene product of Coli phage 434 has been purified from cells carrying lambdaimm434cIdv plasmid known to contain only some of the "early" genes of phage 434 and lambda . It was detected and tentatively identified as tof protein primarily by its ability to specifically bind to phage 434 DNA . The protein has a molecular weight of about 11,000 and requires Mg2+ for specific DNA binding, unlike 434 cI-repressor.

Mol Gen Genet, 1977 Nov 14, 156(2), 121 - 31
Isolation and characterization of mutants of Escherichia coli deficient in induction of mutations by ultraviolet light; Kato T et al.; Mutants of E . coli defective in susceptibility to UV-induction of mutations were isolated by direct screening for their UV nonmutable phenotype (Umu-) . Screening of about 30,000 mutagenized clones of a uvr-B derivative of AB1157 yielded six Umu- strains . The mutants can be classified into three groups by the location of the mutations, umuA, umuB and umuC . Mutations umuA and umuB are, respectively, mapped close to lexA and recA genes and mutations at both loci partially reduce UV mutagenesis . The locus of umuC is between hemA and purB and the mutations at this new locus result in a moderate increase of UV sensitivity . The mutation diminishes UV mutagenesis and UV reactivation of phage lambda without affecting the inducibility of phophage lambda nor the inhibition of cell division following UV irradiation . Related properties of an isogenic strain of a recF- mutant are compared with those of umuC-.

Mol Gen Genet, 1977 Nov 14, 156(2), 115 - 20
Effects of chloramphenicol and caffeine on postreplication repair in uvr A- umuC- und uvrA- recF- strains of Escherichia coli K-12; Kato T; Postreplication repair and its inhibition by chloramphenicol and caffeine, as seen in alkaline sucrose gradients, were compared between a uv non-mutable strain uvrA- umuC- and normally mutable strains uvrA- recF- and uvrA- umu+rec+ of Escherichia coli K-12 . The uvrA- umuC- strain performed postreplication repair as efficiently as the parental strain, while the repair in uvrA- recF- strain was dependent on UV dose . Both chloramphenicol and caffeine inhibited postreplication repair to an equal extent of about 25%, and 10%, respectively, in all three uvrA- strains of umuC36, recF- and umu+rec+ . These observations suggest that postreplication repair is largely not responsible for UV mutagenesis.

J Biol Chem, 1977 Nov 10, 252(21), 7685 - 9
Proteolysis of the bifunctional methionine-repressible aspartokinase II-homoserine dehydrogenase II of Escherichia coli K12 . Production of an active homoserine dehydrogenase fragment; Dautry-Varsat A et al.; The dimeric bifunctional enzyme aspartokinase II-homoserine dehydrogenase II (Mr = 2 X 88,000) of Escherichia coli K12 can be cleaved into two nonoverlapping fragments by limited proteolysis with subtilisin . These two fragments can be separated under nondenaturing conditions as dimeric species, which indicates that each fragment has retained some of the association areas involved in the conformation of the native protein . The smaller fragment (Mr = 2 X 24,000) is devoid of aspartokinase and homoserine dehydrogenase activity . The larger fragment (Mr = 2 X 37,000) is endowed with full homoserine dehydrogenase activity . These results show that the polypeptide chains of the native enzyme are organized in two different domains, that both domains participate in building up the native dimeric structure, and that one of these domains only is responsible for homoserine dehydrogenase activity . A model of aspartokinase II-homoserine dehydrogenase II is proposed, which accounts for the present results.

J Biol Chem, 1977 Nov 10, 252(21), 7678 - 84
Glycosylation of Escherichia coli L-asparaginase; Marsh JW et al.; Reductive coupling with sodium cyanoborhydride has been used with lactose and N-acetylneuraminyl lactose to prepare glycosylated Escherichia coli L-asparaginase . A substantial degree of modification can be achieved without significant loss of enzyme activity . The lactosylated enzyme shows increased thermal stability and resistance to proteolytic cleavage and is cleared more rapidly from the plasma of mice, compared to native asparaginase . The effect on clearance varies directly with the degree of lactosylation . Asparaginase modified with N-acetylneuraminyl lactose, in contrast, with approximately 13.6 mol of N-acetylneuraminyl lactose/mol of enzyme, is cleared more slowly, with a t 1/2 that is approximately twice that of the native enzyme.

J Biol Chem, 1977 Nov 10, 252(21), 7598 - 602
Essential arginine residues in tryptophanase from Escherichia coli; Kazarinoff MN et al.; Tryptophanase from Escherichia coli B/1t7-A is inactivated by the arginine-specific reagent, phenylglyoxal, in potassium phosphate buffer at pH 7.8 AND 25 degrees . Apo- and holoenzyme are inactivated at the same rate, and inactivation of both is correlated with modification of 2 arginine residues/tryptophanase monomer . Substrate analogs having a carboxyl group protect the holoenzyme against both inactivation and arginine modification but have no effect on the inactivation or modification of the apoenzyme . Phenylglyoxal-modified apotryptophanase retains the capacity to bind the coenzyme, pyridoxal-P, but the spectrum of this reconstituted species differs from that of native holotryptophanase . Neither this reconstituted species nor the phenyglyoxal-modified holoenzyme shows the 500 nm absorption characteristic of the native enzyme when substrates are added . These results demonstrate a requirement for specific arginine residues for substrate binding and are discussed in the context of the known conformational and spectal forms of tryptophanase with regard to a possible role for arginine residues in formation of a catalytically effective enzyme-pyridoxal-P complex.

J Biol Chem, 1977 Nov 10, 252(21), 7657 - 61
Studies of the beta-galactoside transporter in inverted membrane vesicles of Escherichia coli . I . Symmetrical facilitated diffusion and proton gradient-coupled transport; Lancaster JR Jr et al.; Facilitated diffusion of {14C}lactose into inverted membrane vesicles of Escherichia coli was measured using HgCl2 as a stopping reagent and polylysine to flocculate the vesicles for filtration . Equilibration of lactose between the internal and external volumes required expression of the y gene of the lac operon and was inhibited by thiodigalactoside or by prior incubation with N-ethylmaleimde or HgCl2 . The initial rate of uptake was saturable, with a Kt of 0.95 mM . Counterflow of {14C}lactose was demonstrated in either direction . ATP hydrolysis or respiration drove the efflux of internal lactose . The effect of ATP required addition of F1 coupling factor (ATPase) from E . coli when lactose transport was studied in F1-deficient inverted vesicles . Accumulation of lactose against a concentration gradient was achieved by forming an artificial electrochemical proton gradient consisting of a membrane potential negative inside or a pH gradient basic inside . Addition of ATP inhibited this proton driven uptake showing that it occurred in inverted vesicles . It was concluded that the lactose-proton co-transport protein (M protein) is qualitatively symmetrical with respect to the facilitated diffusion of lactose and the coupling of proton and lactose transport.

Biochim Biophys Acta, 1977 Nov 7, 500(1), 213 - 6
The mode of condensation of aspartic acid and dihydroxyacetone phosphate in quinolinate synthesis in Escherichia coli; Wicks FD et al.; Dihydroxy {3-14C}acetone phosphate was prepared enzymatically from {1-14C}glucose and use as a substrate in a partially purified quinolinate synthetase system prepared from Escherichia coli mutants . Carbon-by-carbon degradation of the resulting {14C}quinolinate showed that 96% of the 14C was located in carbon-4, indicating that carbon-3 of dihydroxyacetone phosphate condenses with carbon-3 of aspartate in quinolinate synthesis in E . coli.

Mol Gen Genet, 1977 Nov 4, 156(1), 27 - 34
Replication of the ampicillin resistance plasmid RSF1030 in extracts of Escherichia coli: separation of the replication cycle into early and late stages; Staudenbauer WL; The replication cycle of the small resistance plasmid RSF1030 can be divided into two stages with different enzyme requirements: (1) Synthesis of early replicative intermediates containing 7 S DNA catalyzed by DNA polymerase I in the absence of functional dnaZ protein, and (2) replication of early intermediates requiring DNA polymerase III holenzyme (including the dnaZ protein) . Early intermediate DNA synthesized in a dnaZ extract can be converted to fully replicated plasmid molecules upon addition to a replication enzyme fraction prepared by ammonium sulfate fractionation of polA I extracts . The first-stage reaction is sensitive to rifampicin, novobiocin, and oxolinic acid, but insensitive to arabinosylcytosine triphosphate (aCTP) . Addition of aCTP interferes with the second-stage reaction resulting in the accumulation of late replicative intermediates.

Mol Gen Genet, 1977 Nov 4, 156(1), 1 - 7
Growth inhibition of Escherichia coli K-12 by L-valine: a consequence of a regulatory pattern; De Felice M et al.; We studied the production of the ilvG gene product, the valine resistant acetolactate synthase isoenzyme II, in an ilvO+ G+ ilvB ilvHI derivative of Escherichia coli K-12 . This strain contains mutations in the structural genes for the valine sensitive acetolactate synthase isoenzymes I and III . We find that the ilvG gene is not expressed in this strain when gworn with either isoleucine and valine or with isoleucine, leucine and valine, or when limited for either isoleucine or valine . Since we previously found that the ilvG gene is expressed in an ilvO603 containing strain (Favre et al., 1976), we presume that the mechanism by which E . coli K-12 regulates the ilv gene cluster is responsible for the lack of ilvG expression in the ilvO+ strain . The valine sensitivity of E . Coli K-12 is a consequence of this regulatory pattern.

Am J Vet Res, 1977 Nov, 38(11), 1753 - 6
Hemodynamic effects of acute hypoxia and minute amounts of endotoxin in awake swine; Orr JA et al.; Hemodynamic measurements and arterial blood gases were determined from awake swine (n = 8) during acute hypoxia (12% O2, balance N2 for 5 minutes) and following injection of Escherichia coli endotoxin (4 microgram/kg of body weight) into the pulmonary artery . Comparison of baseline data with these treatments indicated: (1) swine exhibited a marked pulmonary pressor response to acute hypoxia (deltaBPpul = 9 to 12 mm of Hg): (2) injection of minute amounts of endotoxin led to a marked increase of pulmonary arterial blood pressure 10 to 20 minutes following the injection (deltaBPpul = 15 mm of Hg); and (3) the pulmonary pressor response to a 2nd exposure of acute hypoxia was unaffected by the intervening endotoxin injection.

Biochim Biophys Acta, 1977 Nov 1, 470(3), 331 - 41
Effect of double-bonds on bimolecular films in membrane models; Legaly G et al.; The effect of unsaturation (especially by cis-bonds) is studied on bimolecular films of saturated and unsaturated alkylammonium ions and alkanols between silicate surfaces as model systems for lipid layers in membranes . Three types of structures are observed: all-trans-blocks, kink-blocks and gauche-blocks . The knowledge of the sequence of these phases and their thermal transitions provides detailed deductions about the role of double-bonds . cis-Unsaturated chains are taken up in bimolecular films as isomers with cis-trans-gauche conformation . This conformation makes the shape of the chain similar to that of kinked chains (chains with gauche-trans-gauche (--) conformation) and enables the incorporation into the film without greater sterical hindrance . The experimental results are in good agreement with X-ray measurements on biological membranes by Engelman (Engelman, D.M., J . Mol . Biol . 47, 115--117 (1970) and 58, 153--165 (1971)).Increasing the concentration of cis-chains decreases the transition temperature of the kink-blocks into gauche-blocks . The variation of the transition temperature with concentration of cis-unsaturated chains in the model system is similar to that observed for Escherichia coli membranes . It is suggested that phase changes in biomembranes are of the same nature: transition of kink-block analogues as ordered phases into gauche-block assemblies as less ordered phases.

Biochemistry, 1977 Nov 1, 16(22), 4848 - 52
Rearrangement of chorismate to prephenate . Use of chorismate mutase inhibitors to define the transition state structure; Andrews PR et al.; The enzymically catalyzed conversion of chorismate to prephenate may proceed through either a chair-like or a boat-like transition state . To distinguish between these alternatives, we have prepared a series of structural analogues of the two possible transition state structures and tested them as inhibitors of chorismate mutase-prephenate dehydrogenase from Escherichia coli K12 . The results indicate that the enzymically catalyzed reaction passes through a chair-like intermediate . None of the compounds studied is an ideal transition state analogue; it seems likely that the partial bond structure of the transition state precludes the corresponding orientation of the side chain in stable molecules . Nevertheless, the new inhibitors are stronger than any previously available, and the degree of inhibition is consistent with bacteriostatic activity recently observed in some of the compounds.

Biochemistry, 1977 Nov 1, 16(22), 4796 - 802
Composition and template activity of chromatin fractionated by isoelectric focusing; Chiu N et al.; HeLa cell interphase chromatin has been sheared and fractionated by isoelectric focusing . Chromatin fractions are obtained with a wide range of isoelectric points . No free DNA is observed . While protein/DNA rations are similar in the various fractions, they appear to contain different nonhistone chromosomal proteins . A minor chromatin fraction with isoelectric point congruent to 7.0 does not contain histone H1 . This fraction is considerably more active as template with different RNA polymerases than the other fractions . Kinetic studies, in which RNA polymerase activity is assayed at various concentrations of chromatin, indicate that the greater activity of Escherichia coli RNA polymerase is due to an increased rate of transcription at saturating concentrations of template (Vmax) and is not due to a lower concentration required for half-maximal rate of transciption (Km) . In contrast, the increased rate of transcription by calf-thymus RNA polymerases II and III is due to a decrease in chromatin concentration required for half-maximal rate of transcription rather than an increased rate of transcription at saturating concentrations of template . These results suggest that chromatin with isoelectric point congruent to 7 offers a greater frequency of binding sites for mammalian RNA polymerases, as would be expected for a "transcriptionally active" fraction.

J Hered, 1977 Nov-Dec, 68(6), 413 - 5
In vitro transcriptional probes of heterotic rat liver chromatin; Tallman G et al.; DNA-dependent RNA polymerase I from E . coli has been used as probe for determining the capacity of purified chromatin isolated from inbred and hybrid rats during the course of postweaning development to serve as template for RNA synthesis in vitro . An analysis of variance reveals both strain- and age-specific differences in the incorporation of {3H}UTP into RNA . The ability of inbred chromatin to support synthesis exceeds that of the hybrid at every age examined except 50 days, with values in the inbred line approaching those in the hybrid line with increasing age . These data suggest that template characteristics may vary substantially with regard to strain and age and may contribute to differences in heterotic development.

Nucleic Acids Res, 1977 Nov, 4(11), 3863 - 76
Steady state kinetic studies of initiation of RNA synthesis on T7 DNA in the presence of rifampicin; Smagowicz JW et al.; The steady state kinetics of initiation of T7 DNA transcription by RNA polymerase holo enzyme from E . coli in the presence of rifampicin and the two substrates ATP and UTP were studied . Under these conditions, the enzyme catalyzes exclusively the promotor specific synthesis of pppApU . The kinetic data are in agreement with the mechanism of a truly ordered reaction . Binding of the initiating nucleotide ATP to the transcriptional complex occurs prior to the binding of the substrate UTP . Release of pppApU is most probably the rate limitinig step . Km constants were found to be 0.6 mM for ATP and 0.31 mM for UTP, respectively . The substrate inhibition pattern indicated that the substrate site exhibits a finite affinity for incorrect nucleoside triphosphate (Ki = 2.3 mM) . A similar non specific binding to the 3-OH site could not be demonstrated.

Cell Biol Int Rep, 1977 Nov, 1(6), 487 - 502
An RNA core in the 30S ribosomal subunit of Escherichia coli and its structural and functional significance; Garrett RA et al.; 1 . Evidence is presented for the occurrence of a very stable RNA core (S4-RNA) in "native" 16S RNA that is also present in the 30S subunit of Escherichia coli . A model giving the approximate location of this RNA core in the 30S subunit is presented . 2 . It is proposed (a) that this S4-RNA acts as a nucleus for the assembly of the 30S subunit, and (b) that a small class of "linkage" proteins, including S4, further facilitate the assembly of the proteins to the RNA, thereby explaining some of the "cooperative" effects that are observed during in vitro assembly . 3 . Evidence for the importance of the RNA core in the functioning of the ribosome is discussed.

Ann Microbiol (Paris), 1977 Nov-Dec, 128B(4), 451 - 7
{Investigation on the incompatibility groups of some colicinogenic factors Ia (author's transl)}; Delhalle E; Compatibility studies of six ColIa factors showed that these plasmids do not always constitute an homogeneous group: four factors belong to the usual Ialpha group, one factor to the O group and the last one is simultaneously incompatible with Ialpha and O plasmids.

Ital J Biochem, 1977 Nov-Dec, 26(6), 444 - 50
Selenalysine as substrate of lysine decarboxylase; Blarzino C et al.; Selenalysine, a lysine analog having the C4 methylene group substituted by a selenium atom, may be decarboxylated to selenolanthionamine by bacterial lysine decarboxylase . The kinetic parameters obtained studying comparatively the decarboxylation of lysine, thialysine and selenalysine showed that while the enzyme is more effective on lysine than on its two analogs, there are no great differences between the last two . These results indicate that the substrate specificity of lysine decarboxylase is greatly affected by the substitution of a carbon atom of the substrate molecule, but the presence of either sulfur or selenium as eteroatom is without appreciable effect on the binding of the lysine analogs to the enzyme . In other words either sulfur- or selenium-containing substrate analogs are acted upon in the same way by lysine decarboxylase.

Res Vet Sci, 1977 Nov, 23(3), 293 - 7
African hamster lymphocytes as a model for immunologic studies; Howell HM et al.; The mitogenic response of splenic lymphocytes from Mystromys albicaudatus was studied to evaluate the potential of this animal as a model for immunologic research . In response to phytochemagglutinin and concanavalin A, splenic cells from Mystromys, unlike those from mouse strains, incorporate {3H} thymidine optimally in microculture at 10(5) to 2 X 10(5) cells per microculture . Maximum magnitude of incorporation in response to the same doses of mitogen used in mouse splenic lymphocyte microculture is greater than 10(5) cpm . Moreover, this high incorporation at low cell concentration has been observed in cultures from animals ranging from six to 24 months of age . Splenic cells from Mystromys give little or no incorporation with either LPS or PPD in doses mitogenic to mouse lymphocytes . These features of mitogenic response in Mystromys lymphocyte cultures suggest several useful applications to studies of mechanisms of mitogenesis.

Acta Physiol Scand, 1977 Nov, 101(3), 264 - 9
Circulatory reflex responses during the initial stage of feline endotoxin shock; Halinen MO et al.; Cardiovascular and autonomic nervous responses to an injection of E . coli endotoxin were followed for up to 15 min . in cats anesthetized with chloralose and given artificial respiration . Within 60 seconds, endotoxin induced a drop of aortic pressure, with simultaneous cardiac acceleration and slight central venous hypertension . There was an associated, almost complete cessation of the aortic arch baroreceptor afferentation . The cardiac sympathetic efferentation increased up to 1.4 times the control level at its maximum . The splenic sympathetic efferentation increased up to 10.6 times the control level at the end of the 15 min period, when the other parameters studied showed a trend to control level . The sympathetic autonomic system seems to be activated through cardiovascular receptors sensing hemodynamic changes touched off by endotoxin-induced release of vasoactive substances.

Nucleic Acids Res, 1977 Nov, 4(11), 3943 - 58
A RNA-dependent RNA polymerase activity: implications for chromatin transcription experiments; Giesecke K et al.; Mercurated nucleoside triphosphates have been used for transcription of chicken oviduct chromatin with E . coli RNA polymerase . The newly synthesized RNA was purified from preexisting RNA by SH-agarose chromatography and analyzed for the content of specific mRNA sequences . The apparent preferential production of ovalbumin mRNA sequences was not inhibited by actinomycin D, although total RNA synthesis was reduced by more than 90% . Furthermore, when globin mRNA alone, or added to oviduct chromatin, was incubated in the transcription assay, a significant fraction of this mRNA was retained on SH-agarose . The copurification of chromatin associated RNA with in vitro synthesized mercurated RNA was mainly due to a RNA-dependent synthesis of complementary sequences by the bacterial enzyme . Although denaturation of the transcripts prior to SH-agarose chromatography leads to a reduced contamination with endogenous ovalbumin specific RNA, we are unable to show that the messenger-specific RNA sequences purified with the newly mercurated RNA results from a DNA-dependent reaction.

Nucleic Acids Res, 1977 Nov, 4(11), 3829 - 38
The binding of berenil to Escherichia coli ribosome; Sinharay S et al.; The binding of the nonintercalating dye berenil to the 70S ribosome of Escherichia coli has been demonstrated by spectrophotometric measurements and gel filtration through Biogel P100 column . The berenil spectrum is gradually shifted towards the red region with the increasing amount of ribosome added, the isosbestic point being at 375 nm . There is positive cooperativity in the binding of berenil to the ribosome as demonstrated by the equilibrium dialysis . On binding with berenil, the ribosome is degraded faster by RNase I especially at low Mg++ concentration and its capacity to inhibit RNase I catalysed hydrolysis of ribopolymers is decreased . These indicate the unfolding of the structure of the ribosome.

Nucleic Acids Res, 1977 Nov, 4(11), 3727 - 41
Demonstration of a tertiary interaction in solution between the extra arm and the D-stem in two different transfer RNA's by NMR; Salemink PJ et al.; According to the X-ray structure of yeast tRNAPhe at 2.5 A resolution, a hydrogen bond is formed between m7G46 and G22 . By removal of this m7G46-residue we demonstrate that this interaction is present in solution as well . Comparison of the 1H 360 MHz NMR spectra of intact yeast tRNAPhe and its m7G-excised derivative locates the position of this tertiary H-bond at 12.5 ppm downfield from DSS . Additional evidence for the presence of this interaction in solution comes from a comparison of 1H NMR spectra of E . coli tRNAf1Met and E . coli tRNAf3Met, which differ only in a single position in the extra arm . In tRNAf3Met residue 47 is a m7G-residue, whereas in tRNAf3Met it is A, resulting in the absence of the m7G47 - G23 - C13 triple interaction, characteristic of tRNAf1Met . The resonance position of this tertiary interaction in tRNAf1Met is located around -13.6 ppm, a chemical shift difference of 1.1 ppm with respect to the position observed for tRNAPhe . The origin of this chemical shift difference is discussed in relation to the structure of their respective augmented D-helices.

J Gen Microbiol, 1977 Nov, 103(1), 37 - 43
Isolation and characterization of cysK mutants of Escherichia coli K12; Fimmel AL et al.; cysK mutants, deficient in O-acetylserine sulphydrylase A {O-acetyl-L-serine acetate-lyase (adding hydrogen-sulphide); EC 4.2.99.8}, were isolated as strains resistant to selenite or giving a black colour reaction on bismuth citrate indicator medium . All were resistant to the inhibitor I,2,4-triazole . Four independent mutants were found which possessed lowered levels of O-acetylserine sulphydrylase activity and also partially constitutive levels of NADPH-sulphite reductase {hydrogen-sulphide: NADP+ oxidoreductase; EC I.8.I.2} . Strains containing both a cysE mutation and a cysK mutation lacked the constitutive levels of NADPH-sulphite reductase showing that these levels were due to the in vivo concentration of the inducer, O-acetylserine . The cysK locus was found to be 81% cotransducible with the ptsI gene.

J Biochem (Tokyo), 1977 Nov, 82(5), 1485 - 9
Involvement of 30S ribosomal protein S1 in poly(U)-directed polyphenylalanine synthesis; Yokota T et al.; The effect of 30S ribosomal protein S1 on poly(U)-directed polyphenylalanine synthesis was studied using a highly purified cell-free system which was devoid of endogenous S1 . The system consisted of homogeneous preparations of EF-Tu, EF-Ts, and EF-G, and 70S ribosomes from which protein S1 had been removed by poly(U)-cellulose column chromatography . It was found that protein S1 was indispensable for translation of poly(U) by an S1-depleted system at low concentrations of poly(U) . On the other hand, at higher concentrations of poly(U), a considerable amount of polyphenylalanine was synthesized in the absence of added S1 . The stimulatory effect of S1 was observed at all Mg2+ concentrations examined but was most pronounced at 10 mM Mg2+ . Some physicochemical properties of the protein were also studied . It was demonstrated that the protein has an elongated shape with an axial ratio of approximately 8.5.

Res Commun Chem Pathol Pharmacol, 1977 Nov, 18(3), 533 - 42
Suppressed immune response to T-cell dependent antigen in chemically sympathectomized mice; Kasahara K et al.; Chemical sympathectomy induced by 6-hydroxydopamine (6-OHDA) suppressed the secondary immune response of mice to a T-cell (thymus derived lymphocyte) dependent antigen, sheep red blood cells (SRBC) . Treatment with 6-OHDA on the day of the secondary injection of SRBC resulted in depression of hemagglutinin titers to the antigen, while treatment with 6-OHDA on the day of the primary injection of SRBC had no effect upon the secondary response to the antigen . In addition, 6-OHDA treatment did not suppress the primary immune response to a T-cell independent antigen, Escherichia coli lipopolysaccharide (LPS) . These results suggest that it is the T-cells which are mainly affected by chemical sympathectomy . Significant non-specific toxicity was not observed with 6-OHDA 100mg/kg, the dose of which suppressed the primary and the secondary immune response to SRBC.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 5104 - 8
Cell--cell interactions in conjugating Escherichia coli: role of traT protein in surface exclusion; Achtman M et al.; Escherichia coli cells carrying the F sex factor are poor recipients in conjugation . This phenomenon is called surface exclusion . Two F cistrons, traS and traT, are independently responsible for part of the whole mechanism . The traS gene product reduces DNA transfer within stable mating aggregates . The traT gene product, pTraT, results in a greatly reduced ability to form stable mating aggregates, and thus also leads to reduced DNA transfer within the cell population . pTraT is a 25,000-dalton protein incorporated into the cell envelope outer membrane . It is found in 29,000-84,000 copies per cell, depending on the plasmid expressing it . There is a parallel variation in recipient ability . Models for surface exclusion are discussed.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 5065 - 8
Domains involving nonrandom distribution of lipopolysaccharide in the outer membrane of Escherichia coli; Leive L; The present data demonstrate that the outer membrane of Escherichia coli contains domains of lipopolysaccharide that do not intermix freely with each other . A strain of E . coli lacking galactose epimerase was grown with galactose, for varying periods of time, which permits formation of a long polysaccharide, and without galactose, which results in a short polysaccharide . Such cultures yielded outer membrane fragments that were heterogeneous in lipopolysaccharide composition, some containing more long- than short-chain lipopolysaccharide, and vice versa . The kinetics of formation of these fragments suggest that lipopolysaccharide initially enters the membrane at points from which it can diffuse but ultimately is organized into domains that do not mix with each other, at least when lipopolysaccharides or different composition are present in the same organism.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 4905 - 8
Isopeptide linkage between N-alpha-monomethylalanine and lysine in ribosomal protein S11 from Escherichia coli; Chen R et al.; Protein S11 from the Escherichia coli ribosome has a unique NH2-terminal structure not previously observed among ribosomal proteins . Owing to the formation of an isopeptide bond between a secondary amino acid (N-alpha-monomethylalanine) and the epsilon-amino group of the NH2-terminal lysine residue, a "branching point" is formed . Therefore, two amino acids are seen when the NH2 terminus of the protein is determined.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 4811 - 5
In vivo site-specific genetic recombination promoted by the EcoRI restriction endonuclease; Chang S et al.; Site-specific genetic recombinations promoted in vivo by the EcoRI endonuclease has been demonstrated by using constructed hybrid plasmids in which the chloramphenicol resistance gene was inactivated by insertion of DNA fragments at an EcoRI site within the gene . Such recombination can involve either the joining of intracellularly generated cohesive termini of the same DNA fragment or intermolecular ligation of different DNA fragments . DNA cleavage and ligation in vivo are precise: recombinant DNA molecules show functional continuity of the gene sequence cleaved by the enzyme and regeneration of nucleotide recognition sites for both the EcoRI endonuclease and the EcoRI DNA methylase . In other experiments, EcoRI-generated fragments of eukaryotic DNA that had not been modified by the Escherichia coli K methylase were shown to be taken up by bacterial cells and to undergo intracellular ligation to segments of bacterial plasmid DNA.

Proc Natl Acad Sci U S A, 1977 Nov, 74(11), 4786 - 90
Escherichia coli ribosomal protein S1 has two polynucleotide binding sites; Draper DE et al.; The interaction of Escherichia coli ribosomal protein S1 with a variety of RNA and DNA oligomers and polymers has been studied, using both a sedimentation technique and the quenching of intrinsic protein fluorescence upon nucleic acid binding to obtain equilibrium binding parameters . Two polynucleotide binding sites have been detected on S1: site I binds either single-stranded DNA or RNA and does not discriminate between adenine- and cytidine-containing polynucleotides, while the II binding is highly specific for RNA over DNA and shows a marked preference for cytidine polynucleotides over the corresponding adenine-containing species . On the basis of the binding properties of S1 to denatured DNA cellulose and poly(rC)-cellulose, it is demonstrated that every S1 molecule carries both a site I and a site II . Some possible implications of these results for mechanisms of protein synthesis and phage Qbeta replication are briefly considered.

Int J Radiat Biol Relat Stud Phys Chem Med, 1977 Nov, 32(5), 457 - 64
Sensitization of Escherichia coli C to gamma-radiation by 5-bromouracil incorporation; Bonura T et al.; Escherichia coli C cells, unifilarly substituted with 5-bromouracil (BrUra) were 2-25 times as sensitive as unsubstituted cells to killing by gamma-irradiation under aerobic conditions . The yield of DNA double-strand breaks in BrUra-substituted cells was increased by a factor only 1-55, suggesting that other lesions also contribute to cell-killing . Alkaline sucrose density gradient analysis of the 3H-thymine labelled DNA strand showed there was less repair of gamma-ray-induced single-strand breaks when BrUra was in the complementary strand . Since there are more of these unrepaired breaks than can be accounted for by BrUra-induced DNA double-strand breakage, some fraction of the lethal events in BrUra-substituted E . coli cells may be unrepaired DNA single-strand breaks.

Infect Immun, 1977 Nov, 18(2), 348 - 51
Escherichia coli heat-labile enterotoxin: comparison of antitoxin assays and serum antitoxin levels; Wachsmuth IK et al.; The mouse adrenal tumor cells (Y-1 strain) and the Chinese hamster ovary cells, two routinely used tissue culture assays for Escherichia coli heat-labile enterotoxin (LT), were used to detect serum antitoxin responses in culture-positive patients from several well-defined sources . There was no correlation between a significant antitoxin response and isolation of LT-producing E . coli in two "domestic" diarrheal outbreaks . Serum samples from a third group of individuals in a rural cholera-endemic area consistently demonstrated significant rises in neutralizing antibody to LT.

Eur J Biochem, 1977 Nov 1, 80(2), 507 - 15
beta-D-Galactoside transport in Escherichia coli: substrate recognition; Sandermann H Jr; 1 . A number of galactosides and other sugar compounds were examined as inhibitors of facilitated or active transport by the lactose permease system of Escherichia coli . Efficient inhibition required an alpha- or beta-anomeric galactopyranosyl ring of D-configuration, a free 6-hydroxyl group, and a certain aglycone size which was reached, for example, by monosaccharide or nitrophenyl substituents . 2 . Aromatic alpha-D-galactopyranosides acted as high-affinity inhibitors (Ki, below 50 micrometer) . At least two of them were not transported, in contrast to alpha-galactoside disaccharides and to aromatic beta-D-galactopyranosides . 3 . beta-D-Galactoside transport was not significantly inhibited by specific inhibitors and transitionstate analogues of beta-galactosidase (D-galactal, D-galactonolascone) . 4 . The beta-D-galactopyranoside, lactitol, and alpha-D-galactopyranoside, galactinol, were not efficiently bound by the lactose permease system, although the maximal rate of uptake of lacitol was similar to that of lactose . By comparison with several structurally related D-galactopyranosides, the decreased affinity was attributed to an effect of the membrane/water interface . A model for substrate recognition by the lactose permease system is presented.

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