Escherichia coli

Carcinogenesis, 1981, 2(1), 33 - 8
4-Chloromethylbiphenyl (4CMB): a novel mutagen and potential carcinogen; Ashby J et al.; The bacterial mutagenicity and cell transforming properties of the monocyclic alkylating agent benzyl chloride have been compared with those of its biphenyl analogue, 4-chloromethylbiphenyl (4CMB), and it is apparent that the addition of the second benzene ring greatly enhances biological activity . The possible reasons for this enhancement are discussed in relation to similar effects observed when comparing the activities of aniline with its biphenyl analogue, 4-aminobiphenyl (4AB) . The marked activity observed for 4CMB, a stable and crystalline solid, suggests that it could prove useful as a direct-acting positive control test chemical for use in short-term mutagenicity tests.

Biophys J, 1981 Jan, 33(1), 93 - 106
Sensitivity of exponentially growing populations of Escherichia coli to photo-induced psoralen-DNA interstrand crosslinks; Grover NB et al.; Experimental survival curves for Escherichia coli K 12 (CR 34) were determined after exposure to 4,5',8-trimethylpsoralen and near ultraviolet light . The lethal action was shown to arise exclusively from interstrand crosslinks, cell vulnerability increasing markedly with the doubling time of the culture . To account for these results, two quite different models are considered . The first assumes that a cell survives as long as at least one copy of its genome remains undamaged; a variant of this permits repair by DNA strand exchange . The second model allows for a limited period of time during which DNA repair can take place . A crosslink in a stretch of DNA due to be replicated within this interval constitutes a fatal lesion . Theoretical survival curves are computed for bacterial populations with defined age distributions and chromosome configurations . While the first model completely fails to provide a satisfactory description of the experimental results, the second model does predict the presence of a shoulder in the survival curves and, in one of its forms, it seems to agree rather well with the measured data over a wide range of crosslink concentrations and doubling times.

Boll Ist Sieroter Milan, 1981, 60(1), 61 - 8
{Preliminary results on the effects of pretreatment with thymic extract on experimental endotoxin hepatitis in the mouse}; Corridori S et al.; The Authors wish to examine the protective effects which a period of pre-treatment with thymostimulin, would have on endotoxin hepatitis, induced in thymectomized and non-thymectomized animals . The test showed that the histological picture and the degree of endotoxinemia, measured with the Lymulus test, benefited from treatment with a thymic extract . This therapy was effect (and was statistically significant) in obtaining an immunorestoring effect (in the thymectomized mouse) and in inducing an immunostimulating effect (in the normal mouse).

Arch Virol, 1981, 68(3-4), 249 - 56
Principles of selective inactivation of viral genome . II . Influence of stirring and optical density of the layer to be irradiated upon UV-induced inactivation of viruses; Budowsky EI et al.; Kinetics of the UV-induced (lambda = 254 nm) inactivation of phage MS2 is studied for stirred and non-stirred solutions with optical densities ranging from 0.06 to 2.1 . The extent of inactivation exhibits exponential dependence on irradiation time for stirred solutions thus indicating the homogeneity of the phage population in respect to photosensitivity of infectivity . Irradiation of the same solution without stirring results in deviation of survival curves from exponential ones (the so called "tailing"), being more pronounced the larger the optical density of the layer under irradiation and degree of inactivation . Such a deviation is conditioned by non-uniform light absorption by virions in solution in the absence of stirring . The inactivation kinetics upon UV-irradiation of the stirred and non-stirred phage solutions is rather accurately expressed by respective equations thus enabling the choice of rational conditions for a given depth of phage inactivation to be performed.

Mol Gen Genet, 1981, 182(1), 44 - 52
Copy number control and incompatibility of plasmid R1: identification of a protein that seems to be involved in both processes; Burger KJ et al.; Investigations into the genetic determinants for incompatibility of miniplasmids and hybrid replicons constructed from wide type and mutant R1 revealed the presence of an incompatibility function at the junction f two small PstI fragments . These two fragments were not distinguished in earlier experiments since they have the same mobility on agarose gels . This incompatibility function is distinct from other inc-determinants of R1 (Kollek and Goebel 1979; Molin and Nordstrom, 1980) and independent of R1-type replication . By means of specific deletions and subcloning of DNA fragments, the location of this new inc-determinant could be determined further . After deletion of this inc-determinant from inc-determinant from miniplasmids, a 5-fold increase in copy number was observed which could then be reduced to a copy number of about 1 plasmid per cell by complementation with hybrid plasmids having this function . Incompatibility of miniplasmids deleted in this determinant is not reduced, whereas analogous deletions introduced into recombinant plasmids nearly abolished their incompatibility . This determinant seems to exert strong incompatibility only when cloned on pBR322 . Therefore, its main function is plasmid R1 is probably restricted to copy control . The appearance of low copy numbers of of miniplasmids carrying this determinant and of trans-acting copy control and strong incompatibility exerted by hybrid plasmids is consistently correlated with the presence of a protein of 11,000 molecular weight, synthesized in relatively large amounts in Escherichia coli minicells.

Mol Gen Genet, 1981, 182(1), 12 - 8
Altered stability and integration frequency of a F' factor in RNA polymerase mutants of Escherichia coli; Gray GW Jr et al.; A number of spontaneous rifampicin-resistant (Rifr) mutants were isolated from a strain of E . coli having a deletion in the lac proA proB region of the chromosome . The stability of a F'lac proA proB episome in these mutants was determined by their sensitivity to acridine orange curing and the frequency of spontaneous loss of episomes . The Rifr mutants can be divided into three classes based on their ability to maintain the F'lac pro episome . Class I mutants (25% of the total Rifr mutants) showed high degree of spontaneous episome loss and high sensitivity to acridine orange curing . Class II mutants (55% of the total Rifr mutants), like the parent strains, showed intermediate sensitivity to acridine orange curing . Class III mutants (21% of the total Rifr mutants) showed high resistance to acridine orange curing and low frequency of spontaneous episome loss . Three-fourths of the Class II mutants were found to be Hfr as shown by their lack of the F'lac pro DNA band on agarose gel together with their ability to mobilize chromosomal markers in mating . Representative Rifr mutants from each class were selected and the Rifr mutants from each class were selected and the Rifr mutations were mapped within the proB gene for the beta beta' operon by P1 transduction . These results indicate that RNA polymerase, or the beta subunit of RNA polymerase, plays an important role in maintaining the F' lac pro episome and in the integration of the F' lac pro episome where no extensive sequence homology is involved.

Mol Gen Genet, 1981, 181(4), 564 - 6
DNA synthesis in Escherichia coli during a nutritional shift-up; Zaritsky A et al.; DNA synthesis in a thymine-requiring Escherichia coli K12 strain was studied by exploiting deoxyguanosine, so simulating the behaviour of Thy+ strains . DNA synthesis is inhibited during the first 24 min after a nutritional shift-up . The new DNA/mass is lower than that predicted by current models for initiation control.

Mol Gen Genet, 1981, 181(4), 535 - 40
Nitrate reductase and cytochrome bnitrate reductase structural genes as parts of the nitrate reductase operon; Bonnefoy-Orth V et al.; The existence of a nitrate-reductase operon in the tryptophane region was deduced from the effects of prophage insertion in each of chlI and chlC genes and from transposition of the Mu-mediated host DNA fragments of F-prime . This operon appears to be polarized from chlC to chlI and the gene order in the region is trp -- chlI -- chlC -- purB.

Mol Gen Genet, 1981, 181(4), 491 - 6
Acetohydroxy acid synthase isoenzymes of Escherichia coli K-12: a trans-acting regulatory locus of ilvHI gene expression; Ursini MV et al.; We isolated an Escherichia coli K-12 regulatory mutation affecting the acetohydroxy acid synthase III isoenzyme . This mutation was found to lie outside the structural genes ilvHI for this isoenzyme and was designated lrs-1 . A strain carrying this mutation was found to be altered in the leucine-mediated control of ilvHI mRNA and acetohydroxy acid synthase III synthesis observed in the isogenic lrs+ strain . These alterations appeared to be a consequence of a reduced intracellular concentration of a single one of five tRNALeu isoaccepting species.

Mol Gen Genet, 1981, 181(4), 441 - 7
DNA sequence of a plasmid-encoded dihydrofolate reductase; Swift G et al.; The sequence of the methotrexate-resistant dihydrofolate reductase (DHFR) gene borne by the plasmid R-388 was determined . The gene was subcloned and mapped by an in vitro mutagenesis method involving insertion of synthetic oligonucleotide decamers encoding the BamHI recognition site . Sites of insertion that destroyed the methotrexate resistance fell in two regions separated by 300 bp within a 1.2 kb fragment . One of these regions encodes a 78 amino acid polypeptide homologous to another drug-resistant DHFR . The second region essential for DHFR expression appears to be the promoter of the DHFR gene.

Mol Gen Genet, 1981, 181(4), 417 - 9
Three-factor reciprocal cross mapping of a gene that causes expression of feedback-resistant acetohydroxy acid synthase in Escherichia coli K-12; Jackson JH et al.; The ilv-662 allele was previously identified as a mutation that caused acetohydroxy acid synthase activity to be resistant to feedback inhibition by valine (Davis et al . 1977) . This allele was mapped between thr and leu by cotransduction analysis and labeled ilvJ . This report describes the mapping of ilvJ relative to genes that lie between thr and leu (ara, carA and pdxA) by three factor reciprocal cross analyses . We find that the probable gene order is thr-carA-pdxA-ilvJ-ara-leu . Although the phenotypic properties of ilvJ662 appear to be quite distinct from brnS, a gene reported to involve branched chain amino acid transport (Guardiola et al . 1974), we do not rule out possible allelism because of the uncertainty of the map position of brnS.

J Urol (Paris), 1981, 87(4), 249 - 51
{Primary vesical pneumaturia in the absence of diabetes (author's transl)}; Lhez JM et al.; Vesical pneumaturia occurring in the absence of any glycosuric diabetes suggested a uro-digestive origin . The pathogenesis of primary pneumaturia, in the absence of diabetes, is discussed on the basis of experimental research . The aetiopathogenic mechanism of this primary pneumaturia remains obscure.

J Immunol Methods, 1981, 41(1), 115 - 24
Application of the Farr assay to the analysis of antibodies specific for UV irradiated DNA; Strickland PT et al.; In order to determine the optimum conditions for reactivity in the ammonium sulphate precipitation (Farr) assay was have studied the DNA binding properties of two antibodies raised against ultraviolet single stranded DNA (UVssDNA) complexed with methylated bovine serum albumin . In general the buffer composition, pH, temperature, and ionic strength conditions described for binding to undamaged DNA were found to be appropriate for binding to UV-irradiated DNA . However, some differences in detail were noted which indicate the necessity for checking the physical conditions of binding of individual antibodies . Mouse monoclonal antibody and rabbit polyclonal antisera bound to UVssDNA very rapidly, even when DNA and ammonium sulphate were added simultaneously, whereas this procedure prevented binding of rabbit antisera to UV-irradiated double stranded DNA . Incubation at 45 degrees C for 30 min inhibited binding by mouse antibody, and incubation at 37 degrees C for 60 min caused reversible dissociation of the DNA-antibody complex . The optimised Farr assay was used to define the antigen specificities of the antibodies . The mouse antibody specifically bound to UVssDNA, but not to ssDNA, double stranded (ds) DNA, or UVdsDNA, whereas the rabbit antisera bound to UVssDNA, ssDNA or UVdsDNA, but not dsDNA . The extent of binding of the mouse antibody was dependent on the UV dose to the antigen, as well as the antigen concentration, indicating that the Farr assay can form the basis of a quantitative assay for photoproducts in DNA.

Chromosoma, 1981, 82(4), 515 - 23
In situ transcription analysis of chromatin template activity of the S-chromosome of Drosophila following high molar NaCl treatment; Chatterjee RN et al.; The chromatin template activity of the polytene chromosomes in larval salivary glands of Drosophila hydei has been assayed by in situ transcription, on the fixed chromatin using E . coli RNA polymerase holoenzyme and 3H-UTP as the monitoring substrate, both with optimal salt and high salt concentration (1 M NaCl) . Results reveal an increase in the net transcription of all chromosomes in the high salt treatment series in comparison with the control . The X-chromosomes of the male larval gland also shows an increase in the labelling following the high salt treatment, but the increase is significantly less than that of the autosomes of the same nucleus . On the basis of these findings it has been suggested that the X-chromosomal hyperactivity of the male, as normally known to exist, might be guided by an inherent modulation of the structure of the X-chromatin.

Annu Rev Biophys Bioeng, 1981, 10, 151 - 74
Applications of 13C NMR to metabolic studies; Scott AI et al.; It is our view that the above examples, most of which have been published in the last two years, represent the beginnings of a new field and that in spite of major problems in instrumentation and programming, the essential feasibility of using enriched 13C substrates for metabolic processes as a noninvasive technique has been firmly established . With the caveat that a rigorous protocol for signal assignment must be devised, we can look forward to many applications of this method in a wide range of biological systems.

Acta Microbiol Acad Sci Hung, 1981, 28(2), 165 - 70
Guanosine polyphosphate production of Escherichia coli stringent and relaxed strains in the stationary phase of growth; Kramer M et al.; Stringent and relaxed Escherichia coli strains grown on minimal and on differently enriched media produced guanosine polyphosphates in the stationary phase of growth . On transition from the logarithmic to the stationary phase, stringent strains started to produce guanosine 5' triphosphate 3' diphosphate (pppGpp) . and guanosine 5' diphosphate 3' diphosphate (ppGpp), while relaxes strains accumulated only ppGpp . When the stringent strain was cultivated on media enriched with Casamino Acids the leve of pppGpp decreased, while with yeast extract an almost twofold increase could be observed . The concentration of ppGpp increased with both nutrients as compared to that measured in minimal medium . Readdition of glucose to the stationary phase culture did not result in the slightest decrease of the nucleoside polyphosphate levels . In contrast, addition of a mixture of 20 L-amino acids or Casamino Acids or yeast extract to the medium caused an abrupt decrease in the guanosine polyphosphate levels . Qualitatively similar results were obtained with the relaxed strains except that the amounts of ppGpp were smaller than in the case of the stringent counterpart and the responses to the resupplementation were slower . Some possible mechanisms regarding the occurrence of guanosine polyphosphates in the stationary phase are discussed.

J Mol Evol, 1981, 17(2), 85 - 93
Evolutionary sequence divergence within repeated DNA families of higher plant genomes . II . Analysis of thermal denaturation; Preisler RS et al.; An assay based on derivative analysis of thermal denaturation (melting) behavior of reassociated DNA was developed in an attempt to characterize the sequence relationships in repeated DNA families according to the homogeneous or heterogeneous models of Bendich and Anderson (1977) . The validity of the technique was confirmed by the use of deaminated Escherichia coli DNA models for repetitive families . The melting data for DNA reassociated at two different temperatures provided strong evidence that Pisum sativum repeated families are mostly heterogeneous, while homogeneous families predominate in Vigna radiata . These findings, together with other differences between the two genomes, suggest that the rate of sequence amplification has been higher in the evolutionary history of Pisum DNA . A general trend seems to exist for high amplification rates in large, highly repetitive plant genomes such as Pisum and lower rates in smaller plant genomes such as Vigna, as well as in the generally smaller, less repetitive genomes of most animal species.

Genetika, 1981, 17(5), 782 - 93
{Mutation affecting the promotor region of the Escherichia coli K-12 deo-operon}; Akhliustina EV et al.; It was shown that the strain SA1030 (Das et al., 1976) contains a mutation (deoPx), which decreases deoR regulated expression of the deo operon . Thymine dependent strain harbouring deoPx mutation decreases requirement in thymine up to 8-10 microgram/ml . The deoPx mutation causes 9 fold and 3 fold decrease in the activity of thymidine phosphorylase and purine nucleoside phosphorylase, respectively in cytR-deoR- strains, i.e . under the conditions of maximal derepression of the operon . The presence of cya mutation in deoPx background causes reduction of the activity of both enzymes to basal level, no matter whether cytR or deoR repressor proteins are present or not . It is supposed that deoPx mutation blocks the activity of the deoP promoter, while the cytP promoter remains unchanged . On the other hand, the deoR mutation gives rise to a rather high level of the activity of deo enzymes in cya+cytR+ strains harbouring deoPx mutation, as compared to those found in the corresponding deoR+ strains . These data may be explained by the conception that two repressor proteins function in a cooperation with respect to repression of the deo-genes (Hammer-Jespersen, Munch-Petersen, 1975) . The deoPx mutation is cotransducible (approximately 50%) with the thr gene and is located near the deo operon to the left of dra, indicating the order of markers on the chromosome to be deoPx--dra--thr . In transduction and conjugation matings deoPx mutation is characterized by a very low frequence or the absence of integration into the chromosomes of some recipient strains . These data, suggest that deoPx mutation is the result of a rearrangement of genetic material in the promoter region of the deo operon.

Chemotherapy, 1981, 27(4), 264 - 9
Effects of doxycycline on the phagocytosis of 32 P-labelled Escherichia coli by human polymorphonuclear cells; Melby K et al.; A study on the effect of various concentrations (2-100 microgram/ml) of doxycycline on the phagocytic activity of human polymorphonuclear cells was undertaken using a radio-labelled strain of Escherichia coli as test particle . In the presence of 10% normal human serum pretreatment with 50-100 microgram/ml resulted in a 50% increase in cell-associated radioactivity . When omitting serum during the ingestion phase, or conducting the ingestion phase at 4 degree C, the ingestive capability was reduced . 2 microgram/ml present during the ingestion together with 10% normal human serum reduced the ingestive capability significantly, whereas the presence of 10 microgram/ml exerted no significant effect . By the use of 3H-labelled doxycycline the drug was shown to be firmly fixed to the leukocyte monolayer.

Biokhimiia, 1981 Jan, 46(1), 92 - 9
{Influence of alcohol lipotropic agents on biosynthesis and repression of secreted alkaline phosphatase in Escherichia coli}; Zemlianukhina OA et al.; Preincubation of cells in the presence of 4% ethanol accompanied by an increase of non-saturated cis-vaccenic acid content was shown to promote synthesis of alkaline phosphatase . Preincubation of cells in 0.1% hexanol reducing the level of this acid, on the contrary, leads to partial repression of the enzyme synthesis; the lag-phase of repression in the cells with a raised content of non-saturated cis-vaccenic acid and, consequently, with a greater fluidity of lipids was also shown to be reduced . Conversely, the reduction of lipid membrane fluidity on ethanol addition simultaneously with the repressing metabolite ortho-phosphate extends the lag-phase of repression and removes it partially during cell cultivation in the presence of ortho-phosphate . The impact of lipid composition variations on the synthesis and repression of alkaline phosphatase is discussed.

Res Vet Sci, 1981 Jan, 30(1), 57 - 61
The influence of Escherichia coli O78 endotoxin on carbohydrate metabolism in the domestic fowl; Curtis MJ et al.; The injection of endotoxin isolated from a pathogenic avian strain of Escherichia coli (1 mg/kg intravenously) accelerated the depletion of liver glycogen in fasting nine- to 10-week-old chickens within the first hour and concurrently reduced their plasma inorganic phosphate levels . These changes were attributed to increased glycogenolysis and were followed by hypoglycaemia and a large increase in the lactate content of the plasma which appeared to be caused by enhanced glucose oxidation and reduced gluconeogenesis . The plasma glucose level returned to normal within three hours and simultaneous changes in the plasma urate and albumin content indicated that glucose was being synthesised from amino acids and that albumin was being catabolised to provide them.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 243 - 6
Nucleotide sequence of cloned rat serum albumin messenger RNA; Sargent TD et al.; The nucleotide sequences of the recombinant DNA inserts of three bacterial plasmid clones containing nearly all of the rat serum albumin mRNA have been determined . A statistical analysis of the nucleotide sequence reveals a pattern of repeated internal homology that confirms the "intragenic triplication" model of albumin evolution.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 215 - 9
Membrane potential changes during the first steps of coliphage infection; Labedan B et al.; Immediately after adsorption, phages T4 and T5 induce a partial depolarization of the host cytoplasmic membrane . Infected bacteria respond to this phage-induced effect by a repolarization that leads to a new steady state of reduced membrane potential . The rate and extent of repolarization are adjusted to the intensity of depolarization, which depends on the number of adsorbed phages . Consequently, the new steady state membrane potential is attained in the same interval of time regardless of the maximum depolarization . These membrane potential changes appear to be independent of phage-specific properties (type of phage, presence of DNA and internal proteins, injection process) and of several membrane-related parameters (temperature, external pH, preinfectious level of membrane potential) . We propose that phage adsorption to the outer membrane triggers the emission of a signal that is transmitted to the cytoplasmic membrane . Additivity of independent signals is possible when stimuli (phages) are added at the same time . Additional adsorption of phages has no further depolarizing effect as soon as the repolarization begins . We propose that this refractoriness to secondary depolarization nd the shut-off of the first depolarization are induced by the same chemical modification also initiated by adsorption of the first phage.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 138 - 42
Prophage (phi 80) induction in Escherichia coli K-12 by specific deoxyoligonucleotides; Irbe RM et al.; A cell preparation that is permeable to proteins and oligonucleotides yet produces infectious phage particles after induction treatments was obtained by plasmolysis of Escherichia coli cells lysogenic for phi 80 . When the permeabilized cells were exposed to specific oligo(deoxynucleotides), prophage (phi 80) was induced during further incubation . Of the dinucleotides tested, only d(A-G), d(G-G), and d(I-G) induced prophage . The essential base sequence of the deoxydinucleotides for the induction was determined to be deoxy(purine-G) . Among oligo(deoxynucleotides) with unique base composition examined, only oligo(deoxyguanylates) exhibited the inducing activity . Although this specific oligo(deoxynucleotide)-triggered induction occurred in recB- cells, the induction was not detected in recA- cells or in the cells lysogenic for induction-negative phi 80(ind-) . Possible biological significance of the oligo(deoxynucleotide)-triggered prophage induction is discussed.

Mol Gen Genet, 1981, 181(3), 411 - 3
Chromosome replication following a temporary inhibition of DNA-synthesis by nalidixic acid in a temperature-sensitive dnaA mutant of Escherichia coli; Khachatourians GG; Chromosome replication cycle in a DNA initiation mutant of Escherichia coli (CRT-83, dnaAts) was blocked by nalidixic acid, an inhibitor of the A subunit of DNA gyrase . Following a period of inhibition of DNA synthesis, the drug was removed and "run-out" DNA synthesis was examined . It was found that the "capacity" for DNA synthesis was not affected by such a treatment.

Mol Gen Genet, 1981, 181(3), 356 - 62
Organization of genes in the four minute region of the Escherichia coli chromosome: evidence that rpsB and tsf are co-transcribed; Bendiak DS et al.; Restriction endonuclease-generated DNA fragments of lambda polC-9 (Friesen et al . 1976) have been cloned on plasmid vehicles . Expression of genes carried by these plasmids was determined either by genetic complementation of the appropriate mutants, or in ultraviolet-irradiated cells . On the basis of these experiments we have inferred the following gene order in the four minute region of the Escherichia coli chromosome: tonA-dapD4-dapD2-rpsB-tsf-22 kilodalton protein - fir 27,000-firA-dnaE . We suggest that rpsB and tsf are in one transcriptional unit, with rpsB being promoter-proximal . We also suggest the possible position of the promoter for dnaE.

Int Arch Allergy Appl Immunol, 1981, 65(3), 300 - 3
Studies on the K antibody response in rabbits immunized with a pool of five different K antigen-containing Escherichia coli; Kaijser B; The Escherichia coli K antibody response in rabbits which were immunized with a mixture of E . coli O1K1H7, O6K2a2cH1, O4K12, O6K13H1 and O6K53, or with only one of these strains, was analyzed using indirect hemagglutination . Some K antigens gave generally high antibody response, while others did not . There were not statistically significant difference concerning K antibody response for each of the K antigens when the rabbits were immunized with one strain or a mixture of strains . The information is important for the composition of a future E . coli vaccine containing several K antigens.

Gene, 1981 Jan-Feb, 13(1), 1 - 12
Variants of a cloned synthetic lactose operator . I . A palindromic dimer lactose operator derived from one stand of the cloned 40-base pair operator; Betz JL et al.; Starting with one strand of the 40-bp synthetic operator (Sadler et al., 1978), we have constructed and cloned a 66-bp, palindromic DNA segment with the following sequence (Formula: see text), where the horizontal arrows indicate the locations of the two 21-bp "core" operator sequences in this segment and the vertical arrow designates the dyad axis of symmetry . Upon denaturation and rapid renaturation, each strand of this fragment forms a hairpin molecule still retaining an EcoRI cohesive end . Two hairpin molecules can be joined with T4 DNA ligase to form a duplex DNA molecule having no ends (dumbbell form A) . Denaturation and rapid renaturation of dumbbell A yields a mixture of two dumbbell forms: dumbbell A which is a substrate for Eco RI, and a new form, dumbbell B, which is not a substrate . Each of the conformations of this DNA fragment have been purified and all are active in binding lactose repressor in vitro.

Adv Biophys, 1981, 14, 1 - 35
Subunit of assembly of Escherichia coli RNA polymerase; Ishihama A; The isolated subunits of Escherichia coli DNA-dependent RNA polymerase are reassembled in a stepwise manner in the following sequence: 2 alpha leads to alpha 2 leads to alpha 2 beta leads to alpha 2 beta beta' (premature core enzyme) leads to E (active core enzyme) . When the in vitro reconstitution is performed at low temperature, the subunit assembly is prevented until the assembled but inactive premature core enzyme is formed, which is similar to native core enzyme in many parameters of gross conformation but differs from it in several minor and local conformations . The temperature-dependent activation of premature core enzyme at a salt concentration as low as that in vivo takes place only in the continuous presence of either the sigma subunit or DNA . The sigma subunit is therefore proposed to be a regulatory protein which influences the conformation of core subunit assembly in multiple ways from the initial enzyme maturation to the final initiation of transcription . Evidence has accumulated which indicates that the subunit assembly in vivo proceeds via the same pathway as that identified in vitro, including the identification of all species of the assembly intermediates in cell extracts, the identification of all possible types of assembly-defective mutants among temperature-sensitive alpha-, beta-, and beta'-subunit mutants, the kinetics of the appearance of pulse-labeled subunits in the enzyme structure as expected from the assembly sequence and the integration of labeled subassemblies into the enzyme structure upon chasing . The functional complexity of RNA polymerase coupled with transcriptional control appears to depend on its structural flexibility which fluctuates through the assembly with various transcription factors . This type of transcriptional control is being thoroughly considered by a final conclusion awaits further examinations.

Poult Sci, 1981 Jan, 60(1), 49 - 53
Genetic and phenotypic correlations between immune response to Escherichia coli and to Newcastle disease virus vaccines; Soller M et al.; Genetic and phenotypic variation and covariation in immune response to inactivated Newcastle disease virus (NDV) vaccine and to Escherichia coli vaccine were studied in commercial poultry strains . Within any given experiment there was no tendency for individual birds to respond in a correlated manner to NDV and E . coli vaccines . There were highly significant differences between sire families in immune response to NDV vaccine (57 sire families) and to E . coli vaccine (35 sire families) . Heritabilities of immune response levels to NDV and to E . coli were .41 and .25, respectively . In both cases, additive genetic standard deviations were slightly over 1.0 titer unit . The correlation between sire-family means for response to NDV and sire-family means for response to E . coli (35 sire families) was .077 and statistically nonsignificant . Thus, the data provide evidence for the presence of significant genetic variation in immune response with respect to two endemic disease antigens, but they provide no evidence for a genetic correlation in response to the two antigens.

Genetika, 1981, 17(2), 258 - 67
{Genetic study of the mutations impairing guanine, xanthine and hypoxanthines assimilation in a purine auxotroph of Escherichia coli K-12}; Brikun IA et al.; The hpt gene is responsible for the synthesis of hypoxanthine-guanine phosphoribosiltransferase . This gene was located between aceE and pan markers on the linkage map of Escherichia coli K-12 by a detailed transductional analysis using P1 phage . As described earlier by Nijkamp and De Haan, the guaC mutation blocks the synthesis of guanosine-5'-monophosphate reductase . The cotransduction frequencies of guaC with leu, azi, nadC, aceE, hpt and pan showed the guaC site to be positioned anterior to nadC marker . The order of these genes appeared to be as follows: leu--azi--guaC--nadC--aceE--hpt--pan.

Genetika, 1981, 17(2), 246 - 57
{Phenotypic manifestation of the pnd mutation, which promotes purine nucleoside cleavage by Escherichia coli K-12 cells, in the genome of strains defective in the metabolism of nucleic acid precursors}; Kocharian ShM et al.; Strains of Escherichia coli K-12 containing both pnd1 mutation, rendering bacteria capable to catabolize purine nucleosides without participation of purine nucleoside phosphorylase (pup gene), and mutations in several genes of purine metabolism or nucleosides catabolism have been constructed . The introduction of the deletion mutation in adenosine deaminase gene (add) into the pup pnd genome does not affect the ability of mutants to utilize adenosine and deoxyadenosine as the sole carbon and energy sources . Mutations affecting purine phosphoribosyltransferases (hpt and gpt) block the ability of pup pnd mutants to utilize hypoxanthine, guanine and their deoxyribonucleosides and also xanthine and xanthosine as the only purine source . A mutation in deoxyribomutase (drm) disturbs the ability of pnd mutants to use all purine ribo- and deoxy-ribonucleosides as carbon and energy sources, whereas a mutation in deoxyriboaldolase (dra) only disturbs utilization of deoxyribonucleosides . These data seem to indicate that the activity promoted by pnd mutations catalyzes the cell reaction of irreversible phosphorolytic cleavage of the N-glycoside bond of the purine nucleosides molecules: purine nucleoside + phosphate leads to purine + pentose-1-phosphate . It is suggested that pnd mutations affect the structural gene of some phosphorolytic enzyme and modify its substrate specificity . Evidence is presented that the structural gene of a new nucleoside phosphorylase is not sensitive to catabolite repression.

Appl Environ Microbiol, 1981 Jan, 41(1), 46 - 50
Cadmium-binding component in Escherichia coli during accommodation to low levels of this ion; Khazaeli MB et al.; An inducible cadmium-binding protein was isolated from Escherichia coli cells accommodated to 3 X 10(-6) M Cd2+ but not from normal or unaccommodated cells . Sephadex G-100, metal chelate affinity chromatography, and disc gel electrophoresis were used in the purification procedure . The molecular weight of the Cd2+-binding protein was estimated to be about 39,000 by Sephadex G-100 chromatography, making it different from the conventional, much smaller metallothionein.

Zentralbl Bakteriol Naturwiss, 1981, 136(1), 3 - 9
Protein composition of Bdellovibrio bacteriovorus and Escherichia coli membranes during their interaction; Severin AI et al.; A comparative study of membrane proteins of Bdellovibrio bacteriovorus and host-bacteria Escherichia coli was performed by polyacrylamide gel electrophoresis in presence of sodium dodecyl sulphate . Infection of E . coli cells by bdellovibrions resulted in the loss of some high-molecular proteins and appearance of new ones in the host-bacteria membranes . The possible role of parasite proteases in degradation of host-bacteria membrane proteins is discussed.

Mol Gen Genet, 1981, 181(1), 24 - 8
Conditional lethality of Escherichia coli strains carrying dnaE and dnaQ mutations; Horiuchi T et al.; A double mutant of Escherichia coli K12 which carries a conditional lethal mutator mutation, dnaQ49 (Horiuchi et al . 1978), and a DNA polymerase III-deficient mutation, dnaE486 (Wechsler and Gross 1971), was found to be more thermolabile than was either of the dnaQ49 or dnaE486 single mutants . The double mutant is able to grow at 28 degrees C but not at 30 degrees C . Under the restrictive conditions DNA synthesis, but not protein synthesis, of the double mutant was suppressed . All the other combinations of dnaQ and dnaE mutation alleles tested so far rendered the cells thermolabile . A dnaZ mutation exerted a similar effect on the dnaQ strain . However, when non-specific temperature-sensitive growth mutations were combined with the dnaQ49 mutation, no such increase in thermosensitivity was observed . There is a possibility that the product of the dnaQ gene interacts directly with the DNA replicating enzyme complex.

Mol Gen Genet, 1981, 181(1), 101 - 6
The influence of colicinogenic plasmids ColIb-P9, ColIa-CA53 and ColV-K30 on the repair, mutagenesis and induction of colicin E1 synthesis; Khmel IA et al.; The presence of colicinogenic plasmids ColIb-P9 and ColIa-CA53 in E . coli K-12 cells, wild-type with respect to repair, enhanced the survival of cells after UV irradiation and increased the frequency of UV-induced argE3 and his-4 reversions, while the presence of ColV-K30 negatively affected repair and mutagenesis . The plasmid ColIb-P9 showed a UV-protective effect in E . coli cells carrying mutations in genes uvrA, uvrB, uvrC, polA, recB, recF, though in none of the mutants did cell survival reach the wild-type level . The effect of ColIb-P9 on mutagenesis did not depend on the uvrA or recB genes . The plasmid's protective effect and the enhancement of mutagenesis depended on the recA+ lexA+ genotype . The frequency of 2-aminopurine-induced mutations was not affected by ColIb-P9 or ColV-K30 . The presence of ColIb-P9 decreased the ability of ColE1-carrying cells to induce colicin E1 synthesis caused by DNA-damaging agents: UV, MNNG, mitomycin C, whereas ColV-K30 increased the percentage of colicin E1-producing cells . These plasmid effects on the level of induction of colicin E1 synthesis were not observed in the case of induction caused by chloramphenicol which did not depend on the products of recA and lexA genes.

J Clin Lab Immunol, 1981 Jan, 5(1), 47 - 51
Age dependence of subpopulations and functions of human peripheral lymphocytes; Birkeland SA; The eventual dependency of a series of immune parameters on age has been studied in a material of 288 normal persons, divided into 2 sexes and with 16 persons in each 5-year age interval between 5 and 95 years, using a cryobiological freezing and storage system for lymphocytes with subsequent testing in large series . Lymphocyte transformation responses were studied after stimulation with a series of mitogens and specific antigens (PHA, PWM, PPD, Con A, SA, EC, CA and SK/SD), as well as with allogene cells in mixed lymphocyte culture . Values were found to decrease with increasing age . No age-dependency could be demonstrated for T and B lymphocytes using rosette formation tests . There was no difference between the two sexes . Thus, increasing age does not change the distribution between T and B lymphocytes, but does lead to a decrease in the function of the cell-mediated response.

Int Arch Allergy Appl Immunol, 1981, 65(1), 102 - 6
Immediate hypersensitivity in the guinea pig conjunctiva . III . long-term persistence of the hypersensitive state and characterization of antibodies; Dwyer RS et al.; The ocular immediate hypersensitivity reaction in guinea pigs to topically applied normal rabbit serum can be evoked as long as 4 years after sensitization . The reaction was as severe and tended to persist for longer than that evoked 6 months after sensitization . Passive cutaneous anaphylaxis tests showed that very high titres of homocytotropic antibodies were present and that both IgE- and IgG1-like antibodies were involved . Sensitization with one set of injections instead of two was not consistently successful and the response on challenge was mild to moderate . Pretreatment of eyes with Isoptocarpine before antigenic challenge had no effect on the response . The addition of bacterial lipopolysaccharide to the first set of sensitizing injections produced hypersensitivity in animals which were otherwise refractory to sensitization.

Infect Immun, 1981 Jan, 31(1), 500 - 3
Production of heat-labile or heat-stable enterotoxins by strains of Escherichia coli belonging to serogroups O44, O114, and O128; Scotland SM et al.; Strains of Escherichia coli which belong to enteropathogenic serogroups usually fail to produce heat-labile or heat-stable enterotoxins . However, 1 of 34 strains of E . coli O44, 9 of 45 strains of E . coli O114, and 18 of 82 strains of E . coli O128 produced heat-labile or heat-stable enterotoxins . Most enterotoxigenic isolates were from tropical or developing countries; all three enterotoxigenic strains isolated in Britain were from patients returned from abroad . Enterotoxigenic strains were of many different flagellar types . Certain enterotoxigenic strains of E . coli O114 and O128 possessed colonization factor antigen I.

Infect Immun, 1981 Jan, 31(1), 42 - 51
K88-mediated binding of Escherichia coli outer membrane fragments to porcine intestinal epithelial cell brush borders; Middeldorp JM et al.; We have examined the interactions between various radiolabeled membrane fractions obtained from an enterotoxigenic Escherichia coli strain and brush borders isolated from porcine intestinal epithelial cells . Outer membrane fragments containing the K88 attachment factor bound tightly to brush borders, whereas cytoplasmic membrane vesicles did not . Three different types of outer membrane preparations were tested: (i) cellular outer membranes isolated from lysozyme spheroplasts, (ii) medium vesicles or outer membrane fragments released into the medium during growth, and (iii) periplasmic vesicles, or outer membrane fragments which were released from the cells during spheroplast formation and were therefore isolated in the periplasmic fraction . Of these fractions, which were heterogeneous, it was always the outer membrane subfraction which bound tightly to brush borders . This binding, which was K88 dependent, may have some physiological significance in view of the association between outer membrane fragments and enterotoxin . Thus, released outer membrane fragments equipped with attachment factors may function as enterotoxin carriers which increase the efficiency with which enterotoxin can be delivered to intestinal epithelial cells.

Infect Immun, 1981 Jan, 31(1), 252 - 60
Respective contributions to protection of primary and booster immunization with Escherichia coli heat-labile enterotoxin in rats; Klipstein FA et al.; The respective contributions to protection of the route and dosage of primary and booster immunizations with Escherichia coli heat-labile enterotoxin were evaluated in rats . The degree of protection was determined by challenge with toxin and viable bacteria in ligated ileal loops, and the serum antitoxin response was assayed by enzyme-linked immunosorbent assay . Primary immunization was effective only when given by the parenteral route . The degree of protection was enhanced a fivefold dosage increase in the primary parenteral immunization in rats given constant dosages of booster immunizations either parenterally or perorally, but not by further dosage increases . In contrast, the degree of protection rose when dosages of the booster immunizations were increased over a 25-fold range . Four weekly peroral, but only two biweekly parenteral, booster immunizations were necessary to achieve strong protection; biweekly combined parenteral and peroral booster immunizations yielded both strong, immediate and extended protection . The degree of protection against the toxin correlated with that against viable bacteria and with elevated serum antitoxin titers: all seven groups with a protection index of greater than 5 against the toxin had strong protection against heat-labile toxin-producing strains and fourfold or greater increases in the antitoxin titers, whereas none of the nine groups with a protection index of less than 3 was protected against bacteria or had an equivalent antitoxin response . These observations show that once an adequate parenteral primary immunization is given, the degree of protection is influenced primarily by the dosage of the booster immunizations, the necessary number of which is dependent on their route of administration.

Infect Immun, 1981 Jan, 31(1), 245 - 51
Comparison of enterotoxic activities of heat-stable enterotoxins from class 1 and class 2 Escherichia coli of swine origin; Whipp SC et al.; Pig small intestine develops age-dependent resistance to some (class 2 strains) enterotoxigenic Escherichia coli while remaining susceptible to others (class 1 strains) . This study tested the hypothesis that class 1 and class 2 strains produce different subtypes of heat-stable enterotoxin (ST) . The dose-response curves of small intestine to crude ST preparations from a class 1 and a class 2 strain were compared in several species . In infant mice, the class 1 ST preparation was less active than the class 2 ST preparation, whereas in rabbits the preparations were equally potent . However, in 1-, 7-, and 14-week-old pigs, the class 1 ST preparation was more active than the class 2 preparation . At low doses, both preparations caused reduced absorption in pigs of all three age groups, and at high doses the class 1 preparation caused secretion in all three age groups . In contrast, at high doses the class 2 preparation caused secretion in 1-week-old pigs but only reduced absorption in older pigs . when class 1 and class 2 ST preparations were fractionated by methanol extraction, in both cases the mouse-negative, pig-positive activity was associated with the methanol-insoluble fraction and mouse-positive, pig-positive activity was associated with the methanol-soluble fraction . The results are consistent with a hypothesis that class 1 and class 2 strains of enterotoxigenic E . coli produce different subtypes of ST and that the response of pig intestine to ST varies with both age and toxin subtype.

Eur J Biochem, 1981, 114(1), 127 - 31
Decrease in the S1 protein of 30-S ribosomal subunits in polyamine-requiring mutants of Escherichia coli grown in the absence of polyamines; Igarashi K et al.; The reason for the decrease of polypeptide-synthetic activity of 30-S ribosomal subunits obtained from two polyamine-requiring mutants of Escherichia coli, grown in the absence of polyamines, has been studied by analyzing the total and split proteins of 30-S subunits by disc gel and slab gel electrophoresis . It was concluded that the decrease of S1 protein in 30-S subunits was responsible for the decrease of polypeptide synthesis in polyamine-requiring mutants of E . coli grown in the absence of polyamines.

Eur J Biochem, 1981 Jan, 113(3), 563 - 8
{Structure of the heptose region of the lipopolysaccharide from Escherichia coli K12 CR34 (author's transl)}; Blache D et al.; The heptose region of the lipopolysaccharide of Escherichia coli K12 CR34 was studied . The glucose linked to the heptose II was found to be substituted by a D-galactose and the linear chain of the core polysaccharide has two (1 lead to 3) linked heptoses . The heptose II is substituted by a lateral (1 leads to 7) linked heptose III and heptose I is linked in (1 leads to 5) to 2-deoxy-D-manno-octulosonic acid . The three sugars of the linear chain, heptose I, heptose II and glucose are substituted by phosphate, pyrophosphate or pyrophosphorylethanolamine group linked to C-4 hydroxyl groups . However, in some polysaccharidic chains one or two substituting groups may be absent . This result may explain the heterogeneity in the length of the core polysaccharidic chains.

Eur J Biochem, 1981 Jan, 113(3), 555 - 61
Succinic semialdehyde dehydrogenases of Escherichia coli: their role in the degradation of p-hydroxyphenylacetate and gamma-aminobutyrate; Donnelly MI et al.; Two physically and genetically distinct forms of succinic-semialdehyde dehydrogenase have been identified in Escherichia coli B . The two enzymes could be separated by filtration on Sephadex G-150 and their apparent molecular weights were 200 000 and 97 000 . The larger enzyme, which is specific for NADP, is induced by growth on gamma-aminobutyrate . Its induction is highly coordinated with that of gamma-aminobutyrate:2-oxoglutarate transaminase, the enzyme which initiates degradation of gamma-aminobutyrate . The smaller enzyme, which is induced by growth on p-hydroxyphenylacetate, has been purified to 98% homogeneity by affinity chromatography in conjunction with conventional methods . Under standard assay conditions this enzyme acts preferentially with NAD but reduces NADP at 15% of the rate observed for NAD, primarily because of a difference in Km . Apparent Km values for succinic semialdehyde and NAD are 13.3 +/- 1.3 microM and 33.7 +/- 1.4 microM, respectively . The subunit molecular weight was estimated to be 55 000, indicating that the native enzyme is dimeric . The NAD-dependent succinic-semialdehyde dehydrogenase is also induced by exposure of cells to exogenous succinic semialdehyde, a treatment which has no effect on the amount of other enzymes of p-hydroxyphenylacetate or gamma-aminobutyrate metabolism . Apparently the gene for this enzyme functions independently from the genes encoding the other enzymes of p-hydroxyphenyl-acetate degradation . As a consequence of its induction mechanism, this NAD-dependent dehydrogenase is also present in extracts of E . coli B grown with gamma-aminobutyrate as sole nitrogen source, in addition to the NADP-specific enzyme involved in gamma-aminobutyrate metabolism . Presumably the NAD-dependent enzyme is gratuitously induced by succinic semialdehyde formed by transamination of gamma-aminobutyrate.

Cell, 1981 Jan, 23(1), 79 - 88
Suppressor mutations that restore export of a protein with a defective signal sequence; Emr SD et al.; A selection procedure is described that should allow the genetic identification of cellular components involved in the process of protein localization in Escherichia coli . This procedure makes use of mutations that alter the signal sequence of the lambda receptor protein (product of the lamB gene), and prevent export of this protein to its normal outer membrane location . Several suppressor mutations have been identified that restore export of the mutant lambda receptor protein . Mapping experiments show that the suppressor phenotype is the result of mutations in any of at least three different chromosomal loci . One class of suppressor mutations, the class containing the largest number of independent isolates, maps in the major ribosomal gene cluster, suggesting that the suppressor phenotype is the consequence of an altered ribosomal protein . This class of suppressors phenotypically suppresses all known export-defective mutations, internal to the signal sequence region of the lamB gene . These results suggest that ribosomes play an important role in the export of lambda receptor to the outer membrane.

Cell, 1981 Jan, 23(1), 229 - 38
Incompatibility properties of Col E1 and pMB1 derivative plasmids: random replication of multicopy replicons; Hashimoto-Gotoh T et al.; The incompatibility properties of Col E1-like plasmids have been examined in Rec+ and RecA- bacteria . Two Col E1- (or two pMB1-) derivative plasmids coreplicated in the same clone for many cell doublings, irrespective of the rec genotype of host bacteria . Their kinetics of segregation were found to be consistent with models that assume a random choice of template molecule for each plasmid replication event, but with models based on a single (master) template molecule per cell . In contrast, minimal coreplication of a Col E1- and a pMB1-derivative plasmid occurred, with the latter type rapidly excluding the former . We suggest here that the pMB1 derivatives, pMB9 and pBR322, are less sensitive than Col E1 derivatives to the putative inhibitor that regulates plasmid replication, due to base sequence differences in their target for the inhibitor, and consider one mechanism whereby the duplication of Col E1-like plasmids might be regulated.

Can J Microbiol, 1981 Jan, 27(1), 81 - 6
Type I nitroreductases of Escherichia coli; Bryant DW et al.; Analysis of partially purified crude extract of Escherichia coli K12 by chromatography and gel electrophoresis has resulted in the separation of three distinct activities which catalyse the reduction of nitrofurazone (semicarbazone of 5-nitro-2-furaldehyde) in the presence of oxygen (type I nitroreductases) . The major enzymatic activity (type IA), which was dependent solely on NADPH as a cofactor, was absent from nitrofurazone-resistant strains NFR 402 and NFR 502, but present in SIL 41, a strain which is only marginally resistant to the nitrofuran . The remaining nitroreductase activities (IB1 and IB2) utilize either NADH or NADPH as a cofactor . These activities coelute from DEAE-cellulose at pH 7.2, but may be differentiated by their behaviour on CM-cellulose at pH 5.8 . The reductase activity missing in SIL 41 was observed in extracts of strain NFR 402 but not NFR 502 . This enzyme (IB1) though retained by DEAE-cellulose had no affinity for CM-cellulose . The only reductase present in extracts of NFR 502 (a nitrofuran-resistant strain selected after two mutational events) was type IB2 . This activity, also detectable in SIL 41 and NFR 402, has not been mapped genetically . An interesting feature of the type IB2 enzyme is its apparent inactivation by MnCl2 which has been routinely used as a partial purification step in the past.

Can J Microbiol, 1981 Jan, 27(1), 147 - 9
The Anderson--Baird-Parker direct plating method versus the most probable number procedure for enumerating Escherichia coli in meats; Rayman MK et al.; Comparison of the Anderson--Baird-Parker direct plating method (DP) and the North American most probable number procedure (MPN) for enumerating Escherichia coli in frozen meats revealed that the DP method is more precise and yields higher counts of E . coli than the MPN procedure . Any of three brands of membrane filters tested was suitable for use in the DP method.

Arkh Patol, 1981, 43(1), 12 - 7
{Early changes in the kidney microcirculatory bed in the generalized Sanarelli-Shwartzman reaction}; Val'kovich EI et al.; Investigations of early changes of renal microcirculation in generalized Sanarelli-Schwartzmann's reaction revealed markedly manifest alterations in endotheliocytes, podocytes, basal membrane of the glomeruli accompanied by disorders in the permeability of their capillaries and disseminated microthrombosis.

Mutat Res, 1981 Jan, 80(1), 15 - 25
The effects of lexA101, recB21, recF143 and uvrD3 mutations on liquid-holding recovery in ultraviolet-irradiated Escherichia coli K12 recA56; Tang MS et al.; Using an Escherichia coli K12 recA strain, we have tested the effects of incorporating additional mutations affecting deoxyribonucleic acid (DNA) repair on ultraviolet-radiation sensitivity and on the expression of liquid-holding recovery (LHR) . (This laboratory had previously shown that a mutation at uvrA, uvrB or uvrC blocked LHR in a recA strain.) In the recA56 background, an additional lexA101 mutation had no effect on UV-radiation sensitivity or LHR . The addition of a recB21 mutation to recA56 did not alter UV-radiation sensitivity, but greatly increased the rate of LHR . The recB gene product (exonuclease V) appears to act as a competitive inhibitor both of excision repair and of photoreactivation under liquid-holding (LH) conditions . The uvrD3 mutation increased the radiation sensitivity of a recA strain, and almost completely blocked LHR . The recA uvrD strain showed more DNA degradation and DNA double-strand breaks during LH than did the recA strain . The recF143 mutation increased both UV-radiation sensitivity and LHR in a recA strain, suggesting that the recF gene product may also function in recA-independent pathways of DNA repair.

J Appl Physiol, 1981 Jan, 50(1), 185 - 90
Effect of methysergide on the acute lung mechanics response to endotoxin; Allison RC et al.; The effect of the serotonin antagonist methysergide on the acute lung mechanics response to endotoxin in anesthetized, paralyzed, mechanically ventilated dogs was investigated . In five dogs given 0.25 mg/kg Escherichia coli endotoxin only, the pulmonary nonelastic resistance (RL) increased to 238% of control and dynamic compliance (CL) decreased to 50% of control . In a second group of five dogs, methysergide (0.25 mg/kg) was shown to markedly attenuate the lung mechanics response to serotonin (0.04 mg/kg), which alone had produced changes in lung mechanics greater than endotoxin . In these same dogs endotoxin administered after injection of methysergide produced an increase in RL to 377% and a decrease in CL to 33% of control . In a third group of five dogs whose lung mechanics response to serotonin was also greater than to endotoxin alone, endotoxin administered after injection of saline produced an increase in RL to 168% and a decrease in CL to 58% of control . Since the response to endotoxin after injection of methysergide exceeded the response after saline, we conclude that serotonin is not a mediator of the acute lung mechanics response to endotoxin.

J Appl Physiol, 1981 Jan, 50(1), 178 - 84
Role of platelet serotonin in the canine pulmonary response to endotoxin; Murphy TL et al.; There is evidence suggesting a role for platelet serotonin (5-HT) in the immediate pulmonary response to endotoxin in the dog (J . Appl . Physiol . 23: 47, 1967) . To further define this role, autologous canine platelets were labeled with 5-{14C}HT in vitro and then reinfused . Subsequently Escherichia coli endotoxin (0.55:B-5, Difco), 2.5 mg/kg, was injected . Within 5 min dynamic compliance (CL) fell by more than 50%, and nonelastic resistance (RL) increased by more than 200% . Despite a 95% decrease in platelet count, less than 10% of the platelet 5-HT was released as determined by changes in the radioactivity of platelet-poor plasma (PPP) prepared from both aortic and pulmonary artery blood . As a positive control, injected of bovine collagen produced a similar decrease in platelet count that was associated with a significant increase in the radioactivity of aortic and pulmonary artery PPP . FInally, rapid injection of a dose of 5-HT equivalent to 25% of the 5-HT in circulating platelets did not cause a change in CL or RL equivalent to that produced by endotoxin . From these data we conclude that endotoxin injection does not cause immediate massive platelet activation and that platelet 5-HT does not play a major role in the immediate pulmonary response to endotoxin.

Eur J Biochem, 1981 Jan, 113(2), 375 - 80
Precursor proteins are intermediates in vivo in the synthesis of two major outer membrane proteins, the OmpA and OmpF proteins, of Escherichia coli K12; Crowlesmith I et al.; The OmpA and OmpF proteins are major outer membrane proteins of Escherichia coli K12 . Their precursors, the pro-OmpA and pro-OmpF proteins, have been detected in vivo in pulse-labelling experiments carried out with {35S}methionine at 25 degrees C . Wehn the pulse was at 37 degrees C, however, no precursors were detected . The pulse-labelled precursors were processed rapidly and quantitatively into mature protein at 25 degrees C . The apparent half-life of the pro-OmpF protein was estimated to be 30 s, and the pro-OmpA protein may be processed even faster . In short pulses (10 s) the precursors of both proteins were the predominant labelled species, indicating that at 25 degrees C processing does not start until chain elongation of the precursor is almost, if not entirely, complete . When French press lysates of cells pulse-labelled for 10 s were subjected to sucrose gradient centrifugation to separate the inner and outer membranes, both precursors comigrated with the inner membrane.

Eur J Biochem, 1981 Jan, 113(2), 349 - 57
Identification of different forms of the murein-bound lipoprotein found in isolated outer membranes of Escherichia coli; Wensink J et al.; The identification of the free and murein-bound forms of the Escherichia coli lipoprotein on dodecylsulphate-polyacrylamide gels was systematically investigated by analyzing the low-molecular-weight proteins (Mr less than 20 000) of both cytoplasmic and outer membranes . The free form of the lipoprotein was identified on 15% polyacrylamide gels as the fastest migrating component (Mr = 7200-7500) of isolated outer membranes; it could be separated from a small cytoplasmic membrane protein (Mr = 6500) which was probably identical to the dicyclohexylcarbodiimide binding proteolipid of the membrane-bound ATPase . Lysozyme treatment of both outer membranes and murein sacculi failed to convert the murein-bound lipoprotein into a fragment of uniform size; instead the bound form appeared as a series of bands consisting of lipoprotein bound to one, two,...eight murein subunits . The composition of this ladder depended on the method used to isolate outer membranes . Beside these lipoprotein bands the outer membrane contained two other proteins, III and V; the relation of these proteins to previously described proteins is discussed.

J Clin Microbiol, 1981 Jan, 13(1), 49 - 53
Properties of binding of Escherichia coli endotoxin to various matrices; Maitra SK et al.; Binding of Escherichia coli O127:B8 endotoxin to a variety of resins and column materials was investigated by measuring the beta-hydroxy myristic acid content (a major component of the lipid A moiety) of endotoxin after hydrolysis by selected ion-monitoring gas chromatography-mass spectrometry . More than 80% of the endotoxin was bound to hydroxylapatite, polystyrene, Dowex 1-X2, and charcoal . The binding of endotoxin to these materials was markedly reduced by the addition of normal or delipidated serum . Phenyl- and octyl-Sepharose bound 56 and 50% of the endotoxin from saline solutions, respectively . Their percent binding was increased significantly in 1 M ammonium sulfate solutions, indicating hydrophobic interactions between endotoxin and phenyl- and octyl-Sepharose . Only 5% of the endotoxin was bound to plastic polymer PSI-HAP-100 beads, and no binding was observed with concanavalin A- and heparin-Sepharose . Study of the in vitro binding of endotoxin to the above material in the presence of serum suggests that the use of these materials in removing circulating endotoxin in vivo is limited.

J Clin Microbiol, 1981 Jan, 13(1), 179 - 83
Toxin detection after storage or cultivation of enterotoxigenic with colicinogenic Escherichia coli: a possible mechanism for toxin-negative pools; Murray BE et al.; Of 100 non-enterotoxigenic Escherichia coli isolated from children with diarrhea in Bangkok, Thailand, 24 were found to produce colicin(s) . Of these, 87% were active against one or more enterotoxigenic E . coli isolated from the same population . Storage of nine enterotoxigenic E . coli with known inhibitory colicin-producing E . coli in different proportions caused 51 of 96 pools to become negative in the suckling mouse assay (heat-stable toxin) and 17 of 52 to become negative in the Y-1 adrenal cell assay (heat-labile toxin) . Cocultivation of the same strains, without prior storage, caused 12 of 96 pools to become negative for heat-stable toxin and 1 of 52 pools to become negative for heat-labile toxin . Storage or cultivation of E . coli in pools may cause negative results in the suckling mouse and Y-1 adrenal cell assays if any of the isolates in the pool produces colicin(s).

J Clin Microbiol, 1981 Jan, 13(1), 139 - 46
Validation of Legionella pneumophila indirect immunofluorescence assay with epidemic sera; Wilkinson HW et al.; Sera from six outbreaks of legionellosis and four outbreaks of pneumonia of other etiologies were tested with the indirect immunofluorescence assay (IFA) as currently performed . The current IFA is at least as sensitive as the original test in detecting cases of Legionnaires disease (78 to 91%) . By using Center for Disease Control criteria for a positive (fourfold increase in titer during convalescence to greater than or equal to 128) or presumptive (single titer greater than or equal to 256) serological test, the specificity exceeded 99% . No cross-reactions against Legionella pneumophila antigens were observed among sera from epidemic cases of Q fever, tularemia, and psittacosis; the only positive L . pneumophila IFA titer among the epidemic Mycoplasma pneumonia sera was reduced to a negative titer with an immunosorbent extracted from Escherichia coli strain O13:K92:H4 . The slight increase in specificity (to 100%), however, was offset by a slight decrease in sensitivity . The sensitivity of the IFA was maximal when a conjugate that detected immunoglobulins G, M, and A was used . IFA titers were not significantly altered by replacing the monovalent serogroup 1 antigen with a polyvalent antigen (serogroups 1 through 4) nor by the presence of rheumatoid factor or heat-labile serum factors.

J Bacteriol, 1981 Jan, 145(1), 88 - 96
Regulatory mutations conferring constitutive synthesis of major outer membrane proteins (OmpC and OmpF) in Escherichia coli; Sato T et al.; An ompB strain of Escherichia coli K-12 lacking major outer membrane proteins OmpC and OmpF was used to isolate a pair of mutants that have restored the ability to synthesize either OmpC or OmpF protein . These mutants were found to produce the respective proteins constitutively under the several conditions where the synthesis in the wild-type strain was markedly repressed; namely, in the absence of the ompB gene function, under restrictive medium conditions, or upon lysogenization with phage PA-2 . The mutations ompCp1 and ompFp9 responsible for such synthesis were shown to be located in the close vicinity of the corresponding structural genes, ompC and ompF . Moreover, the mutations affect the expression of these genes in a cis-dominant fashion . Taken together with other evidence, it was suggested that ompCp1 and ompFp9 represent regulatory site mutations occurring at the promoter regions of ompC and ompF respectively . Relevance of these findings to the genetic control of outer membrane protein synthesis is discussed.

J Bacteriol, 1981 Jan, 145(1), 668 - 71
Cleavage of colicin Ia by the Escherichia coli K-12 outer membrane is not mediated by the colicin Ia receptor; Bowles LK et al.; Colicin Ia can be cleaved by isolated outer membranes prepared from sensitive and resistant (lacking the colicin Ia receptor) strains of Escherichia coli . Both active and heat-denatured colicin Ia are extensively fragmented . Such proteolysis does not occur when colicin Ia is added to whole sensitive or resistant cells . These results demonstrate that cleavage of colicin Ia is not mediated by its outer membrane receptor.

J Bacteriol, 1981 Jan, 145(1), 647 - 50
Use of cir-lac operon fusions to study transcriptional regulation of the colicin Ia receptor in Escherichia coli K-12; Worsham PL et al.; We describe cir-lac operon fusions constructed by using phage Mu d(Apr lac) . Expression of beta-galactosidase in these fusion strains is analogous to known regulatory properties of cir gene expression . It is concluded that the observed regulation by iron of the cir gene is under transcriptional control.

J Bacteriol, 1981 Jan, 145(1), 644 - 6
Escherichia coli K-12 clones that overproduce dam methylase are hypermutable; Herman GE et al.; A strain of Escherichia coli K-12 that overproduces dam methylase 50-fold was found to be hypermutable, and mutations which resulted in loss of excess methylase activity restored mutation frequencies to wild-type levels . These results are consistent with involvement of this deoxyribonucleic acid methylase in mismatch correction.

J Bacteriol, 1981 Jan, 145(1), 472 - 8
Lipid synthesis during the Escherichia coli cell cycle; Carty CE et al.; Lipid synthesis was examined in Escherichia coli cells at different stage of cell division . Exponentially growing cells were pulse-labeled with appropriate isotopes for 0.1 generation time, inactivated, and separated by size on a sucrose gradient . An abrupt increase in the rate of lipid synthesis occurred which was coincident with the initiation of cross walls . In contrast, the rate of protein synthesis during this same interval remained constant, resulting in an increased lipid/protein ratio in dividing cells . No changes in the composition of phospholipid head groups, fatty acids, or phospholipid molecular species were observed in cells at different stages of division . The observed increase in the rate of lipid synthesis may reflect a means by which the activities of membrane-associated enzymes are modulated during cross wall formation.

J Bacteriol, 1981 Jan, 145(1), 459 - 65
High-efficiency, temperature-sensitive suppression of amber mutations in Escherichia coli; Zengel JM et al.; We have constructed a high-copy-number plasmid carrying an allele of the supD gene (supD43,74) . The plasmid conferred temperature-sensitive suppression of amber mutations . Strains carrying the plasmid exhibited 50 to 60% suppression at 30 degrees C but little or no suppression at 42 degrees C . After a temperature shift from 30 to 42 degrees C the efficiency of suppression decreased gradually over a 60- to 90-min period before reaching the 42 degrees C steady-state level of suppression.

J Bacteriol, 1981 Jan, 145(1), 43 - 9
Methyl-accepting chemotaxis protein III and transducer gene trg; Hazelbauer GL et al.; A comparison of the two-dimensional gel patterns of methyl-3H- and 35S-labeled membrane proteins from trg+ and trg null mutant strains of Escherichia coli indicated that the product of trg is probably methyl-accepting chemotaxis protein III . Like the other known methyl-accepting chemotaxis proteins, the trg product is a membrane protein that migrates as more than one species in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, implying that it too is multiple methylated . It appears likely that all chemoreceptors are linked to the tumble regulator through a single class of membrane protein transducers which are methyl-accepting proteins . Three transducers are coded for by genes tsr, tar, and, probably, trg . Another methyl-accepting protein, which is not related to any of these genes, was observed.

J Bacteriol, 1981 Jan, 145(1), 429 - 33
Role of peptide chain elongation factor G in guanosine 5'-diphosphate 3'-diphosphate synthesis; Pao CC et al.; In a wild-type strain (relA+) of Escherichia coli, starvation of amino acid led to an immediate cessation of the synthesis of stable ribonucleic acids, together with the accumulation of an unusual nucleotide, guanosine 5'-diphosphate 3'-diphosphate, commonly known as ppGpp . This compound also accumulated during heat shock . When temperature-sensitive protein synthesis elongation factor G (EF-G) was introduced into E . coli NF859, a relA+ strain, the synthesis of ppGpp was reduced to approximately one-half that of wild-type EF-G+ cells at a nonpermissive temperature of 40 degrees C . Furthermore, fusidic acid, an inhibitor of protein synthesis which specifically inactivates EF-G, prevented any accumulation of ppGpp during the heat shock . We suggest that a functional EF-G protein is necessary for ppGpp accumulation under temperature shift conditions, possibly by mediating changes in the function of another protein, the relA gene product . However, EF-G is probably not required for the synthesis of ppGpp during the stringent response, since its inactivation did not prevent ppGpp accumulation during amino acid starvation.

J Bacteriol, 1981 Jan, 145(1), 35 - 42
Multiple forms of methyl-accepting chemotaxis proteins distinguished by a factor in addition to multiple methylation; Hazelbauer GL et al.; Methyl-accepting chemotaxis proteins are central to both the excitation and adaptation phases of chemotactic behavior . Using null mutations in the genes coding for the two major methyl-accepting proteins (tsr and tar), we identified the gene products among the membrane proteins of Escherichia coli visualized on one- and two-dimensional gels . On two-dimensional gels, both the tsr and the tar proteins appeared as a group of multiple spots arranged in two to four diagonal arrays . The multiplicity of forms could not be completely explained by the previously documented heterogeneity of the methylated proteins resulting from different numbers of methylated glutamyl residues per polypeptide chain . We suggest that there is at least one other way besides extent of methylation in which the polypeptides of a methylated protein can differ.

J Bacteriol, 1981 Jan, 145(1), 341 - 7
Increased binding of a hydrophobic, photolabile probe to Escherichia coli inversely correlates to membrane potential but not adenosine 5'-triphosphate levels; Wolf MK et al.; We describe conditions for a quantitative determination of azidopyrene binding to Escherichia coli cells . In addition, we define conditions whereby irradiation of azidopyrene in the presence of cells leads to irreversible association of probe with cells . This is presumably due to the light-dependent generation of reactive nitrenes and subsequent incorporation of nitrenopyrene moieties into cellular components . These methods allowed us to determine that the amount of azidopyrene bound to cells was inversely correlated with the magnitude of the cellular membrane potential, but was not correlated with high or low adenosine 5-triphosphate levels per se . Cells bound more azidopyrene if the delta psi was low . Cell-bound azidopyrene was found to be entirely associated with the inner and outer membrane . We suggest that the decreased association of hydrophobic probes upon energization of whole cells reflects a rapid transition in structural properties of the cell envelope.

J Bacteriol, 1981 Jan, 145(1), 293 - 8
Use of gene fusions to determine the orientation of gene phoA on the Escherichia coli chromosome; Sarthy A et al.; We present genetic evidence which demonstrates that the phoA gene is transcribed in the clockwise direction on the Escherichia coli chromosome, in contrast to an earlier proposal . Our conclusion is based on analysis of various genetic fusions between the lac operon and the phoA gene.

J Bacteriol, 1981 Jan, 145(1), 211 - 20
Regulation of hexuronate system genes in Escherichia coli K-12: multiple regulation of the uxu operon by exuR and uxuR gene products; Robert-Baudouy J et al.; New regulatory mutants of Escherichia coli K-1 carrying alterations of the uxuR gene were isolated and characterized . In the presence of superrepressed or derepressed uxuR mutations, mannonic hydrolyase (uxuA) and oxidoreductase relationship analyses suggested that the uxuR gene product acted as a repressor in the control of uxuA-uxuB operon expression . uxuR mutations were localized near min 97, and the following gene order was established: (argH)-uxuR-uxuB-uxuA-(thr) . Properties of exuR (point and deletion) mutants showed that both exuR and uxuR regulatory gene products were involved in the control of the uxuA uxuB operon . Analysis of exuR uxuR double-derepressed mutants suggested that exuR and uxuR repressors act cooperatively to repress the uxu operon.

J Bacteriol, 1981 Jan, 145(1), 113 - 21
Two interacting mutations causing temperature-sensitive phosphatidylglycerol synthesis in Escherichia coli membranes; Nishijima M et al.; A conditionally lethal mutant of Escherichia coli lacking phosphatidylglycerol in vivo at 42 degrees C has been previously isolated by two-stage mutagenesis (M . Nishijima and C . R . H . Raetz, J . Biol . Chem . 254:7837-7844, 1979) . In the first step (designated pgsA444) the phosphatidylglycerophosphate synthetase is partially inactivated, but the resulting strain continues to make about two-thirds of the normal level of phosphatidylglycerol and is not temperature sensitive . The second lesion, termed pgsB1, causes temperature-sensitive growth and phosphatidylglycerol synthesis in strains harboring pgsA444 . The pgsA locus appears to be the structural gene for the synthetase and maps near min 42 . In the present study we mapped the pgsB1 mutation and characterized its interaction with pgsA444 by genetic and biochemical methods . Unexpectedly, pgsB1 was not a second lesion in the pgsA structural gene, but rather mapped at a distinct site near minute 4 . P1 vir-mediated contransduction suggested the gene order pantonA-dapD-pgsB-dnaE (clockwise) . Independent evidence for the genetic mapping was provided by the identification of two hybrid ColE1 plasmids (pLC26-43 and pLC34-20 . L . Clarke and J . Carbon, Cell 9:91-99, 1976) which both carry pgsB+ and dnaE+ . Introduction of either the pgsA+ or the pgsB+ gene (via episomes, hybrid plasmids or P1 vir transduction) suppressed the temperature sensitivity of the double mutant (pgsA444 pgsB1) and restored normal levels of phosphatidylglycerol at 42 degrees C . In addition, strains with the pgsA+ pgsB1 genotype produced a novel lipid (X) at all temperatures, whereas the double mutant (pgsA444 pgsB1) contained two unusual lipids (X and Y) after 3 h at 42 degrees C . Both X and Y are precursors of lipopolysaccharide, and introduction of pgsB+ into the double mutant caused the disappearance of X and Y . Although the biochemical basis of the pgsB1 lesion is unknown, its existence suggests a previously unrecognized link between lipopolysaccharide and phosphatidylglycerol syntheses in E . coli.

Endocrinology, 1981 Jan, 108(1), 353 - 6
Hybridization histochemistry: use of recombinant DNA as a "homing probe" for tissue localization of specific mRNA populations; Hudson P et al.; A procedure, termed hybridization histochemistry, has been developed to locate in specially prepared whole sections of tissue those areas which contain specific mRNA populations . Three 32P-labelled recombinant DNA probes were used; one complementary to endorphin mRNA, one complementary to growth hormone mRNA and one a fragment of bacterial DNA . The specific cell populations or tissue regions binding the probe were identified by autoradiography . Hybridization histochemistry is thus similar in principle to immunohistochemical procedures . The endorphin probe consistently labelled the rat pituitary pars intermedia which is known to be particularly rich in the corresponding mRNA . Likewise the growth hormone probe specifically labelled the anterior pituitary . Control tissues were not labelled by either probe, nor did the bacterial DNA probe significantly label any tissue, providing further evidence of the specificity of the procedure . These results, which are highly reproducible, indicate that the mRNA species for endorphin and growth hormone are present in whole sections of pituitary in a physical state which leaves them accessible to cDNA probes . This initial success provides encouragement that hybridization histochemistry, with further refinement, should have wide applicability in the localization and semi-quantitative analysis of intracellular mRNA in whole frozen sections of tissue.

Br J Surg, 1981 Jan, 68(1), 55 - 8
Alanine metabolism in patients with chronic infection; Royle GT et al.; Alanine matabolism was studied in surgical patients with chronic infection and non-infected control subjects by means of an intravenous infusion of alanine . Septic patients had low basal blood concentrations of alanine compared with control subjects but alanine half-life was similar in both groups . This suggests that low basal alanine concentration in the septic patients was due to decreased release from muscle rather than increased hepatic uptake . Alanine infusion in septic patients caused a fall in the blood concentration of ketone bodies which was initially raised . Similar increases in blood concentrations of glucose, lactate, pyruvate an insulin occurred in both septic and control patients after alanine infusion . Hyperketonaemia may limit muscle breakdown and alanine release in patients with chronic infection.

Am Rev Respir Dis, 1981 Jan, 123(1), 79 - 84
Emphysema associated with intravascular leukocyte sequestration . Comparison with papain-induced emphysema; Guenter CA et al.; The pulmonary effects of endotoxin-induced, repetitive, intravascular leukocyte sequestration were studied in dogs and were compared to the effects of intratracheal papain . Lung specimens from 7 animals receiving 20 to 23 weekly injections were histologically and physiologically similar to those from 10 control animals . Dogs receiving 50 injections of endotoxin during 17 wk developed histologic evidence of emphysema as seen on whole lung sections, a significant increase in mean linear intercept, and loss of elasticity at high lung volumes . The group of animals given intratracheal papain also developed histologic evidence of emphysema, with increased mean linear intercepts and loss of lung elasticity . However, the effects on lung elasticity were much greater in the papain group . Endotoxin-induced, repetitive leukocyte sequestration in the lungs results in mild emphysema; however, similar changes in alveolar size appear to cause less effect on the pressure-volume loop than does papain-induced emphysema.

South Med J, 1981 Jan, 74(1), 71 - 3
Hepatic abscess resulting from asymptomatic diverticulitis of the sigmoid colon; Liebert CW Jr; I have described a case of pyogenic liver abscess secondary to completely asymptomatic diverticulitis . Because extensive diverticulitis may be present with minimal or no clinical symptoms, it should be strongly considered as the cause when dealing with a so-called "cryptogenic" liver abscess, and treatment should be planned accordingly.

Mol Gen Genet, 1981, 183(1), 175 - 80
Mutations affecting translational fidelity in the eucaryote Podospora anserina: characterization of two ribosomal restrictive mutations; Picard-Bennoun M; Fifty-nine mutations that restrict suppressor efficiency were selected in the fungus Podospora anserina using four different screening methods . Previous genetic analysis has shown that these antisuppressors lie in six loci and that they could be similar to ribosomal restrictive mutations known in Escherichia coli . The present study deals with the response of two of them, AS1-1 and AS6-1, to paromomycin and low temperature both in vivo and in vitro . The data demonstrate that ribosomes of the mutant and double-mutant strains are equally resistant to the ambiguity effect of paromomycin . These data are the first demonstration of mutations that increase translational fidelity in eucaryotic organism.

Mol Gen Genet, 1981, 182(3), 505 - 7
Structure and properties of the region of homology between plasmids pMB1 and ColE1; Bhagwat AS et al.; Physical maps of the two independently isolated Escherichia coli plasmids, pMB1 and ColE1, were prepared with 13 restriction endonucleases and compared . A 5.1 kilobase continuous region covering 55% of pMB1 and 75% of colE1 was found to have similar, but non-identical, restriction maps . The differences in the maps of this region probably arose by localized mutational events rather than by major sequence rearrangements . The F-factor was found to mobilize pMB1 efficiently for conjugal transfer . A region on pMB1 required for its F-mediated transfer was mapped . Results of our study combined with results of other investigators suggest that pMB1 and ColE1 share functional properties such as colicin production, colicin immunity, mode of replication, and mobilization by the F-factor, and that the sequences required to code these functions are contained within the 5.1 kilobase homologous region.

Aust N Z J Med, 1981, 11(Suppl 1), 109 - 11
IgA, glomerulonephritis and liver disease; Woodroffe AJ; Data from our Unit suggest that soluble immune complexes (IC) are responsible for the mesangial deposits of IgA and C3 in patients with IgA nephropathy . These IC are of intermediate size (9-17S) and contain IgA, IgG and less commonly IgM . Ubiquitous exogenous antigens have been implicated in some patients and primary defects in antigen exclusion or reticuloendothelial sequestration have been proposed to account for the formation and persistence of IC . The liver plays a central role in the clearance of antigens, polymeric IgA and IC, and liver disease is associated with alimentary hyperimmunization, hypergammaglobulinaemia (including IgA polymers) and circulating IC . At autopsy, mesangial (14/28), skin (10/18) and choroid plexus . (2/3) deposits of IgA were found in patients with alcoholic cirrhosis compared with 1/15, 3/10 and 2/5 respectively in controls . Raised serum antibodies to E . coli and to BSA were noted in patients with alcoholic cirrhosis but no specific antibodies have been detected in the kidney eluates . Circulating IC and mesangial deposits of IgA and C3 have also been demonstrated in rats with carbon tetrachloride-induced cirrhosis and after portacaval shunting . Measurement of reticuloendothelial function and the clearance of IgA polymers and IC is now required in patients with primary IgA nephropathy and HSP . In the meantime, IgA nephropathy is best regarded as a syndrome with primary and secondary forms, and as a clinical spectrum from isolated glomerulonephritis to systemic IC disease (HSP).

Mol Gen Genet, 1981, 181(3), 352 - 5
Transcription of colicin E1 plasmid: electron-microscopic mapping of promoters; Naumova GN et al.; The promoters of ColE1 plasmid DNA have been localized . Their position has been determined relative to the functional map of the plasmid . The direction of transcription from each promoter has been established . Superhelical ColE1 DNA was transcribed in vitro by Escherichia coli RNA polymerase . The resulting complexes of DNA with nascent RNA were treated with restriction endonucleases EcoR1 and SmaI and observed in an electron microscope . Statistical analysis of RNA distribution on DNA made it possible to localize the promoters and determine the direction of transcription from them . The analysis was based on a specially prepared computer program.

Toxicology, 1981, 21(2), 169 - 78
The effect of phospholipid-containing surfactant from nickel exposed rabbits on pulmonary macrophages in vitro; Wiernik A et al.; Alveolar macrophages from 9 normal rabbits were incubated in vitro for 3 h with and without phospholipid-containing surfactant from nickel-treated ones . The macrophages treated with surfactant showed morphological and functional criteria of increased activity . The cell surface had many protrusions and the cytoplasma contained several lamellated structures . The oxidative metabolism, measured by the nitroblue tetrazolium (NBT)-test, at rest and after E . coli stimulation was increased, as was the attachment and ingestion of yeast particles . The NBT-values were about the same as corresponding values of macrophages lavaged from the lungs of nickel-treated rabbit . Macrophages incubated with surfactant from untreated animals, had NBT values and phagocytic activity similar to cells incubated without surfactant . As this substance was administered in excess, the difference in macrophage response would probably be due to a qualitative alteration of the surfactant after nickel exposure.

Adv Shock Res, 1981, 6, 163 - 74
The effect of compensation of acidosis on survival in endotoxin shock; Bastiaans JC et al.; IP injection of 10 mg E . coli endotoxin in fasted female rats causes 100% mortality while hemodynamic effects are absent . A progressive fall in blood glucose to extremely low values with a concomitant rise in plasma lactate is recorded . Plasma pH falls below 7.00 . Infusion of glucose or glucose and insulin does not prolong the survival time . An infusion of 5% NaHCO3 preventing the terminal acidosis has no effect on the survival time and dose not affect the blood glucose and plasma lactate concentrations . Artificial ventilation has no effect on survival time or on blood glucose and plasma lactate concentrations.

Mol Gen Genet, 1981, 184(3), 355 - 8
Enhanced recombination between F42lac and lambda plac5: dependence on F42lac fertility functions; Porter RD; F42lac recombination with lambda plac5 is normally twentyfold to fiftyfold higher than recombination between lambda plac5 and a chromosomal lac gene . The presence of an fi+ R1 plasmid in the same cell as F42lac dramatically reduces this enhanced recombination level while the fi- R1drd19 plasmid has little effect . When F42lac traJ90 is tested in a sup+ strain, it shows a sharp reduction in recombination with lambda plac5 that can be largely reversed by the presence of a supF mutation that partially suppresses the traJ90 nonsense mutation . It is concluded that the enhanced recombination between F42lac and lambda plac5 is largely dependent on the constitutive expression of F42lac fertility functions.

Mol Gen Genet, 1981, 183(3), 528 - 31
Codon binding and translational properties of an isoaccepting lysine tRNA peculiar to virus-transformed Cells; Bjercke RJ et al.; Isoaccepting lysyl-tRNAs from virus-transformed cells in culture were fractionated in the RPC-5 system into peaks 1, 2, 4, 5a, 5, and 6 . tRNALys6 previously was found predominantly associated with transformed cells . The codon response of each peak was determined in an E . coli ribosomal binding assay . tRNALys1, tRNALys2, and tRNALys4 are highly specific for the 5'AAG3' codon . tRNALys5 and tRNALys5a preferentially bind in response to AAA . tRNALys6 binds in response to AAA 3-fold better than in response to AAG . The presence of thiolated nucleosides in the anticodon regions of tRNALys5a, tRNALys5, and tRNALys6 is indicated by I2-inactivation of aminoacylation ability with no effect on the other is isoacceptors . Functional abilities of the isoacceptors were compared in a wheat germ translational system with tobacco mosaic virus RNA as messenger . All of the isoacceptors function about equally well in translation except for tRNALys6, which is only 14 to 24% as effective as the other isoacceptors.

Mol Gen Genet, 1981, 183(1), 54 - 8
A mutation in the RNA polymerase beta' subunit causing depressed ribosomal RNA synthesis in Escherichia coli; Oostra BA et al.; Macromolecular synthesis in an Escherichia coli mutant with a temperature-sensitive beta' subunit of RNA polymerase was analysed . At the non-permissive temperature ribosomal RNA synthesis is strongly reduced while messenger RNA synthesis is affected to only a slightly extent . The overall protein synthesis is only slightly affected . We conclude that the beta' subunit is involved in promoter recognition and plays a role in transcriptional selectivity.

Nucleic Acids Symp Ser, 1981, (9), 225 - 8
Cell-free expression of the beta-galactosidase gene: a model system to study the effects of nucleotide analogs on transcription-translation; Zimmer M et al.; A cell-free system for the expression of the beta-galactosidase gene was employed to study the effects of the UTP and CTP analogs: s2UTP, s2CTP, f5UTP and rTTP on transcription-translation . From the analogs investigated, only rTTP turned out to be able to substitute UTP in the cell-free synthesis of beta-galactosidase . In case of the other analogs listed above, the incorporation of even a small fraction of analog into rRNA resulted in drastic inhibition of beta-galactosidase synthesis.

J Immunol Methods, 1981, 44(2), 125 - 33
A rapid solid-phase enzyme-linked binding assay for screening monoclonal antibodies to cell surface antigens; Cobbold SP et al.; A solid-phase enzyme-linked binding assay is described for screening monoclonal antibodies to cell surface antigens . E . coli beta-galactosidase was coupled to rabbit anti-rat Ig and used to detect the binding of rat monoclonal antibodies to cells which had been fixed to the wells of microtitre plates using a combination of poly-L-lysine and glutaraldehyde . This method was found to be advantageous for the large screening of monoclonal antibodies with a panel of cell types, and has been useful in the selection of antibodies which would be candidates for differentiation markers within the human and mouse haemopoietic systems.

Folia Microbiol (Praha), 1981, 26(3), 212 - 6
A lipopolysaccharide from Aspergillus flavus conidia; Budinska O et al.; A lipopolysaccharide was isolated by extraction of Aspergillus flavus conidia with 45% phenol at 68-70 degrees C . Quantitative analysis revealed 7% nucleic acids, 5.5% proteins, 46% polysaccharides and 49% liquids, of which 12% were covalently bound . Glucose, mannose, galactose and fucose were detected as monosaccharide components of the polysaccharide moiety by gas chromatography; palmitic acid, stearic acid, oleic acid, linoleic acid and myristic acid were mainly present in the lipidic fraction . This material differs from the bacterial lipopolysaccharides, both in composition of the polysaccharide moiety and representation of fatty acids in the lipidic fraction.

Chromosoma, 1981, 83(2), 199 - 208
Characterization of macronuclear DNA in five species of ciliates; Steinbruck G et al.; Macronuclear DNA of four hypotrichous and one holotrichous ciliate species was characterized by biochemical techniques . The renaturation kinetics of the macronuclear DNAs of all five species were similar . Repetitive sequences occur only in an amount below 2% . Although the DNA content of the macronuclei of the species differs considerably, the kinetic complexity of the macronuclear DNA is rather uniform (around 3 x 10(10) daltons, i.e., 4-11 x the E . coli genome) . Only in the macronuclei of the hypotrichous species the DNA exists as gene-sized fragments.

Carcinogenesis, 1981, 2(6), 553 - 8
Minor products from the reaction of (+) and (-) benzo{a}-pyrene-anti-diolepoxide with DNA; Osborne MR et al.; The reaction of trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo{a}pyrene (BP-diolepoxide) with deoxyguanosine has been studied . In addition to the expected N2-guanine derivative minor products resulting from reaction at the O6 and 7-positions have been identified . Reaction of racemic, (+) or (-) BP-diolepoxide with {14C} and {3H}purine labelled DNA allowed these same products to be identified and their yields estimated . It was found that the O6 and 7-guanine products were derived mainly from reaction of the (-)isomer . The 7-substituted guanine derivative in DNA was unstable, undergoing either spontaneous release of the substituted guanine or imidazole ring opening.

Mol Gen Genet, 1981, 182(1), 137 - 42
Plasmid-mediated UV-protection in Myxococcus xanthus; McCann K et al.; Plasmid R46 was successfully transferred from Escherichia coli K=12 into myxococcus xanthus strain MD-1 but not into M . xanthus strain XK . Plasmid R68.45 was transferred from E . coli K-12 into both strains of M . xanthus . The effects of these plasmids on survival of M . xanthus after ultraviolet (UV)-244 nm irradiation, the ability of M . xanthus to reactivate irradiated myxophages, and weigle reactivation of UV-irradiated effect on UV survival of M . xanthus, but increased the host's ability to reactivation irradiated myxophages . Plasmid R68.45 protected M . xanthus strains MD-1 and XK against the lethal effects of UV irradiation and also increased the host's ability to reactivate irradiated myxophages.

Mol Gen Genet, 1981, 181(4), 518 - 21
Promoter sites in the genome of B . subtilis phage SPP1; Stuber D et al.; Transcriptional complexes formed in vitro using DNA of B . subtilis phage SPP1 as template and E . coli and B . subtilis RNA polymerases were analyzed by electron microscopy . Both enzymes recognize the same five strong promoters in the early region of the genome . Strand selection at these sites was identical with both enzymes . These results correlate well with data obtained from in vivo transcription studies . Transcriptional activity in the late region of the genome was very low, not permitting the identification of promoter sites.

Genetika, 1981, 17(5), 932 - 5
{Phenotypic properties of Escherichia coli K-12 purine auxotrophs with disordered synthesis of guanine, xanthine and hypoxanthine phosphoribosyltransferases}; Brikun IA et al.; Purine auxotrophs of Escherichia coli completely blocked for reutilization of guanine, xanthine and hypoxanthine via phosphoribosiltransferase reactions (purD hpt gpt) were studied . They lost the ability to utilize inosine as the source of carbon and purines though retained the purine nucleoside phosphorilase activity . The bacteria of this genotype were also found to be sensitive to leucine, despite the presence of relA+ allele . These phenotypic properties of the purD hpt gpt bacteria were suppressed by the introduction of cya mutation which affects cAMP synthesis into their genome . It has been shown that exogenous cAMP inhibits growth of purD hpt gpt (cya+) bacteria and this has been considered to suggest that purD hpt gpt cya bacteria have an increased pool of purine nucleotides as a consequence of a decrease in the catabolite-sensitive genes activity.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 464 - 8
Osmotic control of kdp operon expression in Escherichia coli; Laimins LA et al.; Turgor pressure, the difference in osmotic pressure across the inner membrane, has been found to regulate expression of the kdp operon in Escherichia coli . The kdp operon codes for a high-affinity repressible transport system for the uptake of potassium . We have studied the regulation of Kdp expression in a strain in which the gene for beta-galactosidase, lacZ, was placed under control of the kdp promotor . Neither internal nor external K+ concentrations directly controlled Kdp expression . Only when the external K+ concentration was reduced to the point of limiting growth was the kdp operon expressed . An increase in external osmolarity at constant K+ concentration, a procedure that reduces turgor pressure, caused expression of the kdp operon . As the magnitude of the osmotic shift was increased, corresponding to greater decreases in turgor pressure, the amount of Kdp expression also increased . The kdp operon thus appears to be controlled by changes in a physical force, the turgor pressure.

Am J Vet Res, 1981 Jan, 42(1), 94 - 9
Therapeutic effect of phenylbutazone on experimental acute Escherichia coli endotoxemia in ponies; Burrows GE; Phenylbutazone (PBZ), a classic anti-inflammatory and prostaglandin-synthesis inhibitor drug, was used to determine the role of prostaglandins and other mediators on the development and perpetuation of the response to intraperitoneal Escherichia coli endotoxin administration . The PBZ (15 mg/kg of body weight) was administered IV 30 minutes after endotoxin administration and was repeated later at 6 and 12 hours at a dose of 10 mg/kg . A variety of evaluation measurements (hematologic, blood glucose, pyruvate, lactate and fibrinogen, serum beta-glucuronidase, prothrombin time, blood gases, hepatic glycogen, plasma esterase, capillary refill time, and rectal temperature) were utilized . Marked alterations were noted for all evaluators following endotoxin administration except for blood fibrinogen, prothrombin time, and plasma esterase activity . The PBZ therapy blocked the hemoconcentration, hyperglycemia, increased blood lactate, decreased bicarbonate, decreased blood pH, pyrexia, and prolonged capillary refill time responses associated with endotoxin administration . Despite the significant blocking effects of PBZ on endotoxin responses, the eventual survival rate was unaffected in these experiments.

Acta Histochem Suppl, 1981, 23, 137 - 43
The nature of the intramembraneous particle; Verkleij AJ et al.; It is argued that the different modes of fracturing of the erythrocyte membrane and the outer membrane of Escherichia coli with respect to the intramembraneous particles have their definite biochemical and structural counterpart i.e., . the non-complementary particles of the erythrocyte membrane being predominantly proteinaceous in nature and the complementary particles of the outer membrane of E . coli being determined by lipopolysaccharide . Evaluation of the complementarity aspect of intramembraneous particles shows than an assessment of complementarity in replicas may decisive when interpreting micrographs at the macromolecular level.

J Biochem (Tokyo), 1981 Jan, 89(1), 223 - 9
Enzyme immunoassay for antibodies in serum using a covalent chromatographic method for separation of the bound label; Yamamoto R et al.; A sensitive enzyme immunoassay system for the measurement of antibodies in serum was developed by the use of a separation method based on the thiol-disulfide interchange reaction . Serum samples including antibodies (anti-insulin, anti-human chorionic gonadotropin, or anti-beta-D-galactosidase) were incubated with antigens labeled with beta-D-galactosidase from Escherichia coli . Each reaction mixture was then passed through a small column (0.1 ml) of (anti-IgG)IgG-Sepharose 4B, in which the (anti-IgG)IgG had been coupled by means of a disulfide bond . The column was washed to remove the unbound label, then the antibody-bound label was eluted from the column with a buffer containing 25 mM dithiothreitol, which cleaved the disulfide bonds between the Sepharose matrix and the anti-IgG antibody molecules . By measuring the enzyme activity in the eluate, the amount of antibodies could be determined even in a serum sample which contained antibodies corresponding to as little as 0.01% of the standard antisera . Preliminary experiments showed that the present method can be used to detect the anti-insulin antibody in the sera from insulin-treated diabetic patients.

J Clin Microbiol, 1981 Jan, 13(1), 1 - 5
Modified Elek test for detection of heat-labile enterotoxin of enterotoxigenic Escherichia coli; Honda T et al.; The Elek test was modified for detection of the heat-labile enterotoxin of enterotoxigenic Escherichia coli . A total of 164 strains of E . coli were tested by the modified Elek test, and the results correlated well with those of the Chinese hamster ovary cell assay and passive immune hemolysis . It is concluded that the modified Elek test is a simple and reproducible assay method for identification of E . coli which produce heat-labile enterotoxin, and is suitable for use in clinical laboratories.

J Bacteriol, 1981 Jan, 145(1), 641 - 3
Mechanism of the rel defect in beta-galactosidase synthesis; Foley D et al.; Relaxed (relA) mutants of Escherichia coli are defective in beta-galactosidase synthesis during amino acid limitation . We show here that this defect comprises both a transcriptional component and a translational component.

Int Arch Allergy Appl Immunol, 1981, 64(2), 190 - 4
Immune complexes and cryoproteins in ascitic fluid of patients with alcoholic liver disease; Quismorio FP Jr et al.; 27 paired specimens of ascitic fluid and serum obtained from patients with alcoholic liver disease were tested for cryoproteins and immune complexes by the C1q binding assay . 20 sera (74%) and ten ascitic fluid (37%) had significant amounts of cryoproteins . The cryoproteins were of the 'mixed' type of cryoglobulins consisting of IgG, IgM, IgA, C3 and C1q . The C1q binding test was positive in 17 sera (63%) and in 16 ascitic fluid (59%) . Intracytoplasmic inclusions of immunoglobulin and complement were found within the ascitic fluid leukocytes by direct immunofluorescence . The presence of immune complexes in the ascitic fluid may be important in the reduction of the complement level of cirrhotic ascitic fluid.

Reprod Nutr Dev, 1981, 21(2), 177 - 83
{tRNA adaptation and the optimization of translation}; Garel JP et al.; The intracellular level of each tRNA species is adjusted to the codon frequency of the mRNA being decoded . This was first observed in such highly differentiated cells as the silk gland of Bombyx mori, which produces fibroin and sericin, and the rabbit reticulocyte . tRNA adaptation also occurs in other cell types from E . coli to mammalian cells . Regardless of the mechanism regulating tRNA biosynthesis, we believe that tRNA adaptation is the basic step optimizing chain elongation at the ribosomal level . We propose the system of trial and error as a working model for the ribosome . This model clarifies the correlations between iso-accepting tRNA levels and codon frequencies, as well as the effect of tRNA pool balance on mean elongation rate and non-uniform individual elongation rate (depending on whether codons are rare or abundant) for fibroin mRNA translated in a reticulocyte cell-free system.

Mol Gen Genet, 1981, 184(3), 457 - 9
Lysogenic induction of lambdoid phages in lexA mutants of Escherichia coli; Sedgwick SG et al.; UV irradiation of lexA3 mutants of E . coli caused lysogenic induction of prophage lambda, lambda i21, lambda i434 and phi 80 . Maximal induction in lexA3 lysogens needed less UV than in lexA+ bacteria and gave 25-100% of the normal levels of infective centres induced . Assays of gene expression arising from derepression of a defective lambda prophage showed at least 40% of the normal levels of induction by mitomycin C in lexA3 bacteria . The need for post-irradiation protein synthesis for lysogenic induction in lexA3 lysogens was reduced by increasing the basal level of recA protein with a recA+ plasmid . It is concluded that in lexA E . coli some recA protein synthesis, too small to be detected by physical means, is needed for UV induced lysogenic induction.

Mol Gen Genet, 1981, 184(1), 68 - 72
A temperature sensitive Reca protein of Escherichia coli; Hickson ID et al.; The temperature sensitive allele recA200 has been cloned into the multiple copy number plasmid pBR322 and the gene product isolated . The purified RecA200 protein is temperature sensitive in ability to cleave the phage lambda and LexA repressors in vitro and also in ability to promote a successful search for homology between single stranded DNA and a homologous duplex leading to D-loop formation . However, at the non-permissive temperature the RecA200 protein has approximately wild type single stranded DNA dependent ATPase activity and ability to promote pairing between homologous single DNA strands . The demonstration that the temperature sensitivity in vivo can be correlated with the temperature sensitive cleavage of the lambda and LexA repressors in vitro and also with D-loop formation shows that these in vitro reactions, which require large amounts of RecA protein, are not carried out by trace amounts of contaminating proteins.

Mol Gen Genet, 1981, 183(3), 514 - 7
Negative regulation of beta and beta' synthesis by RNA polymerase; Lang-Yang H et al.; The genes for the beta and beta' subunits of RNA polymerase, rpoB and rpoC, and the genes for the two ribosomal proteins, rplL and rplJ, are part of the beta operon . Although this operon and contains a single strong promoter, the genes of the operon are not always coordinately expressed in vivo . This has now been confirmed in vitro where the lack of coordinate expression has been shown to be correlated with the selective inhibition of rpoB and rpoC gene expression by RNa polymerase . Rifampicin, which stops the initiation of transcription, also relieves this autogenous inhibition of beta and beta' (beta beta') synthesis . The inhibitory action of RNA polymerase and its reversal by rifampicin most likely occurs at a posttranscriptional or translation level.

Mol Gen Genet, 1981, 183(3), 484 - 9
Rac-E . coli K12 strains carry a preferential attachment site for lambda rev; Diaz R et al.; Lambda rev is a hybrid lambdoid phage formed by recombination between lambda and a defective lambdoid prophage (Rac) present in most E . coli K12 derivatives . We show here that three independently derived Rac-E . coli K12 strains are specifically deleted for the entire Rac prophage consistent with loss of Rac by excisive recombination between hybrid attachment sites that flank the prophage (c.f . excision of a lambda prophage) . lambda rev, in which int and PP' of lambda have been replaced by integrative recombination genes and an attachment site derived from Rac (Gottesman et al . 1974), integrates site-specifically and in the correct orientation at the preferential attachment site generated by Rac excision.

Mol Gen Genet, 1981, 183(3), 463 - 72
The genes for the eight subunits of the membrane bound ATP synthase of Escherichia coli; Hansen FG et al.; The genes for the eight subunits of the membrane bound ATP synthase of Escherichia coli (Ca++, Mg++ dependent ATPase, EC 3.6.1.3) were mapped through genetic, physical and functional analysis of specialized transducing phages lambda asn (von Meyenburg et al . 1978) . The ATP synthase genes, designated atp1, are located at 83.2 min in a segment of the chromosome between 3.5 and 11.3 kb left (counterclockwise) of the origin of replication oriC . The counterclockwise order of the genes for the eight subunits, the expression of which starts from a control region at 3.5 kb-L, was found to be: a, (c, b, delta), alpha, gamma, (epsilon, beta) which in the notation of Downie el al . (1981) reads atp B (EFH) A G (C D) . The analysis was in part based on the isolation of new types of atp (unc, Suc-) mutations . We made use of the fact that specialized transducing phages lambda asn carrying oriC can establish themselves as minichromosomes rendering asnA cells Asn+, and that the resulting Asn+ cells grow slowly if the lambda asn carries part or all of the atp operon . Selecting for fast growing strains mutations were isolated on the lambda asn which either eliminated atp genes or affected their expression ("promoter" mutations) . The relationship between these atp mutations and the cop mutations of Ogura et al . (1980), which also appear to map in front of or within the atp genes, is discussed.

Mol Gen Genet, 1981, 183(3), 428 - 36
Identification of the protein products of the rrnC, ilv, rho region of the Escherichia coli K-12 chromosome; Gray JE et al.; Two methods have been used to identify the protein products of the Escherichia coli K-12 ilv region at 84 min and the flanking rrnC (counterclockwise) and rho (clockwise) loci . First, a set of lambda dilv specialized transducing phages, including some phages that carry rho and others that carry part of rrnC, was used to infect UV irradiated cells . The proteins produced by the infecting lambda dilv phage were selectively labelled with radioactivity amino acids and identified by SDS gel electrophoresis and autoradiography . Second, restriction enzyme fragments were cloned from the lambda dilv phage into pBR322 and the plasmid specific gene products produced in maxicells were similarly identified by SDS gel electrophoresis and autoradiography . The proteins produced were correlated with specific genes and restriction enzyme fragments present in the lambda dilv phage and the pBR322 derivatives . Several ilv gene products that have previously been refractory to protein purification attempts have been identified for the first time by this technique . The presence of mutations at the ilvO site is shown to activate the cryptic ilvG gene and to result in the production of a 62,000 dalton protein . A 15,000 dalton protein of unknown function is synthesized from a DNA segment between ilv and rrnC . The rho gene was cloned from lambda dilv phage into pBR322 and shown to be dominant to a rho mutation on the host chromosome . The rho gene product and four additional proteins coded by genes near or between rho and ilv have been detected.

Mol Gen Genet, 1981, 184(2), 308 - 11
The influence of host DNA replication on the formation of infectious and transducing Mu-particles; Teifel J et al.; We have investigated the influence of bacterial DNA replication on the formation of infectious and transducing Mu-particles . The data obtained agree with the previous findings that growth of phage Mu is independent of the host dnaA gene product (Toussaint and Faelen 1974), but required bacterial replication forks (Fitts and Taylor 1980) . The replication of transducing DNA during phage development (Teifel and Schmieger 1979) is controlled by the host and is not a precondition for its packaging . Packaging of transducing DNA does not require a a nearby Mu genome.

Mol Gen Genet, 1981, 183(1), 74 - 7
Complementation of a dnaC initiation defect in vitro; Projan SJ et al.; The dnaC28 mutant, CT28-3b, is an initiation defective dnaC strain . Extracts of the mutant failed to synthesize DNA in vitro when the strain was incubated at the restrictive temperature for two generation times prior to preparation of the extract . Addition of a complementing extract from a Col-E1::dnaC+ hybrid plasmid containing strain or of partially purified dnaC protein resulted in substantial synthesis . Hybridization of the DNA made by these in vitro complementation extracts showed that a significant portion of this DNA was from the region near the chromosomal origin of replication.

Mol Gen Genet, 1981, 183(1), 130 - 3
Effect of the dnaN mutation on the growth of small DNA phages; Taketo A; The effect of the dnaN mutation on the growth of single-stranded DNA phages was studied by burst experiments . In HC138 dnaN cells exposed to 42.5 degrees C at 5 min before infection, growth of spherical (microvirid or isometric) phages such as alpha 3, phi Kh-1 and phi X174 was partially reduced at the nonpermissive temperature . When infection was performed at 30 min after temperature shift-up, viral replication was completely inhibited at 42.5 degrees C in the dnaN strain but not in a dna+ revertant . At 41 degrees C, multiplication of filamentous (inovirid) phages M13 and fd was restricted specifically in HC138 F+ dnaN bacteria . When dnaN cells lysogenic for lambda i21 were grown at 42.5 degrees C for 60 min and then shifted down to 33 degrees C, a burst of lambda i21 occurred with concomitant cellular lysis, manifesting induction of the prophage development.

Mol Gen Genet, 1981, 183(1), 115 - 22
Strains of Escherichia coli carrying the structural gene for histidyl-tRNA synthetase on a high copy-number plasmid; Eisenbeis SJ et al.; That portion of the Escherichia coli chromosome carried by a number of lambda transducing phages, all of which carry the gua operon, was mapped using restriction endonucleases . The DNA from one of these transducing phages was subcloned onto pBR322 . We have identified two recombinant plasmids which carry the Escherichia coli gene hisS, the structural gene for histidyl-tRNA synthetase . The two plasmids, pSE301 and pSE401, have in common a 3,540 bp fragment of E . coli DNA which is bounded by BglII and SalI restriction endonuclease recognition sites . Strains carrying these plasmids overproduce histidyl-tRNA synthetase 20 to 30 fold . The growth rate of these strains is not affected although the histidine biosynthetic enzymes are derepressed . This derepression seems to be in addition to that caused by introduction of a hisT mutation on the chromosome.

Genetika, 1981, 17(10), 1771 - 83
{Mapping of mutations within the genes coding for enzyme I and Hpr proteins of the phosphoenolpyruvate-dependent phosphotransferase system of Escherichia coli K-12 . I . Mapping of the mutations within the ptsI gene}; Rusina OIu et al.; Fine genetic mapping of the pts region coding for general components of PTS was performed . Over 30 spontaneous pts mutations were investigated . By means of the complementation test using the F'trp+ purC+ ptsI episome, both ptsI and ptsH mutations were revealed among them . With the help of reciprocal three point transduction crosses, 8 of them were situated in the pts region . Two of them were in ptsH gene, the rest being in ptsI gene . The lysogenic strain was obtained with lambda inserted in the pts region . Heat curing of the lysogene led to a number of deletions and insertions . Six of them were mapped with the help of the point mutations studied.

Nephrologie, 1981, 2(3), 107 - 8
{Hypothesis: immune complex glomerulonephritis and auto-immunity (author's transl)}; Fournie GJ et al.; Experimental studies on the NZBxNZW mouse lupus disease and on the development of immune complex (IC) glomerulonephritis in mouse infected with Escherichia coli lead us to state the following hypothesis: two types of factors are implicated in the development of immune complex glomerulonephritis: 1) specific factors leading to the production of IC involving antigens from the triggering agents; 2) non specific factors leading to the production of IC involving auto-antigens.

Mol Gen Genet, 1981, 182(3), 477 - 9
Operon fusions in the nitrate reductase operon and study of the control gene nir R in Escherichia coli; Chippaux M et al.; Strains carrying operon fusions between the promotor of the chl I gene and the lac structural genes were constructed . From these strains in which the expression of the lac genes is under the control of both nitrate and oxygen, spontaneous regulatory mutants were selected: (i) mutants which synthesize beta-galactosidase constitutively in anaerobiosis; (ii) mutants in which beta-galactosidase synthesis is no longer repressed by oxygen . Introduction of the nir R mutated allele into strains carrying these fusions resulted in the total loss of beta-galactosidase synthesis, confirming that nir R is a regulatory gene controlling the expression of the biosynthesis of the nitrate reductase.

Carcinogenesis, 1981, 2(10), 981 - 90
Formation of macromolecular complexes and other effects of DNA treatment with diethyl and dimethyl sulfate: physico-chemical and electron microscopic studies; Kubinski H et al.; In vitro exposures of isolated DNA to one of the two carcinogenic and mutagenic chemicals, diethylsulfate or dimethylsulfate, induces several kinds of physicochemical and morphological alterations . These changes are detectable by a variety of independent techniques . A fraction of DNA treated briefly with either of these two chemicals moves during velocity centrifugation experiments less rapidly than the bulk of control DNA and more rapidly through gels during electrophoresis . This apparent decrease in size is paralleled by the formation of large DNA aggregates with mobilities indicating molecular weights several times that of the untreated, control DNA . The presence of a basic protein in the incubation mixture increases the rate of formation of such complexes . the tendency of the alkylated DNA to bind to both biological and non-biological materials is reflected in the increased attachment of DNA to columns built with methyl-esterified serum albumin and in its quantitative retention on nitrocellulose filters . DNA exposed to dimethylsulfate decreases its density in CsCl gradients . A mixture of two or more DNAs of different densities exposed to this chemical produces an u.v.-absorbing band which is found in such gradients at an intermediate density . If the alkylation reaction is carried out in the presence of a protein, a portion of DNA bands at a density intermediate between the density of DNA and that of the protein, even in the presence of an ionic detergent in the gradient . Under the electron microscope the alkylated DNA shows multiple single-strand breaks and peeling-off whiskers of denatured DNA . Aggregates of DNA molecules become visible upon further incubation of DNA with the alkylating agent . We suggest that the DNA-DNA and DNA- protein complexes play an important role in the process of carcinogenesis and mutagenesis.

Mol Gen Genet, 1981, 182(2), 349 - 54
Construction and physical mapping of plasmids containing the MetA gene of Escherichia coli K-12; Michaeli S et al.; Plasmids containing the metA gene of E . coli K-12 were constructed in vitro using pBR322 as the cloning vehicle and lambda metA transducing phage as the source of metA DNA . EcoRI digests of pBR322 and lambda metA20 were joined by ligase and plasmids carrying the metA gene were selected after transformation in a metA deletion strain . Recombinant DNA molecules contained one pBR322 fragment and one lambda metA20 fragment of 12.2 kb which was present in either of two possible orientations . Plasmids constructed by BamHI digestion of lambda metA2 contained a single bacterial DNA fragment of 5.8 kb inserted in the tet gene . Insertion of the metA fragment led to loss of resistance to tetracycline in one orientation and partial resistance in the opposite orientation.

Circ Shock, 1981, 8(5), 543 - 50
Exdotoxin-induced metabolic changes in the conscious, unrestrained rat: hypoglycemia and elevated blood lactate concentrations without hyperinsulinemia; Adeleye GA et al.; The effects of E coli endotoxin on the plasma concentrations of glucose, lactate, and immunoreactive insulin (IRI) were studied in conscious unrestrained rats . Additionally the effects of endotoxin on glucose-induced elevations in the plasma IRI concentration and on the rate of disappearance of an intravenous glucose load were examined . After a transient and small hyperglycemia endotoxin administration resulted in a progressive, dose-dependent decrease in the plasma glucose concentration and a marked elevation of plasma lactate . The initial hyperglycemia was accompanied by a small, transient increase in the plasma IRI concentration . There was no increase in the plasma IRI concentration during the development of hypoglycemia . The hypoglycemic effect of endotoxin was fully manifest in streptozotocin diabetic rats which displayed low insulin concentrations initially and throughout the experiment . Endotoxin injection produced a significant reduction in the plasma IRI response to glucose administration and a decrease in the rate of disappearance of a glucose load . It is suggested that the metabolic effects of endotoxin in the rat are not mediated by an increase in insulin secretion.

Radiat Environ Biophys, 1981, 19(4), 239 - 45
UV-induced reactivation and mutagenesis of lambda-phages after treatment with 8-methoxypsoralen or thiopyronine and light; Yasui A et al.; Lesions, which were produced on lambda-phages DNA by the photosensitization effect of 8-methoxypsoralen (8-MOP) can be repaired by UV-induced repair systems (W-reactivation) in Escherichia coli wild type host cells . By optimum induction of the repair system, about 45% of the 8-MOP lesions are repaired . The survival of lambda-phages inactivated by the photodynamic action of thiopyronine (TP) is only negligibly increased by the same UV-induced repair systems . However, the frequencies of clear plaque mutations of 8-MOP treated as well as TP treated lambda-phages increase in similar fashion if the host cells of wild type have been irradiated with UV . These results show the different capacities of induced repair systems in repairing different types of lesions . They also suggest that some types of base damages are repaired more error-prone than other DNA-lesions.

Mol Gen Genet, 1981, 181(2), 201 - 6
Genetic analysis of mu or mini-mu containing F' pro lac episomes after prophage induction; Toussaint A et al.; We have investigated the fate of different F pro lac episomes carrying a Mu or mini-Mu, after induction of the Mu or mini-Mu prophage, by looking at the frequencies of transfer of the episome and of one chromosomal marker . During the first 10 min after induction the frequency of chromosome mobilization increases while the frequency of episome transfer decreases . This suggests that the F interacts with the chromosome through some kind of Mu mediated process . Later the transfer of both the episome and chromosomal markers is inhibited . Possible reasons for this inhibition are discussed.

Genetika, 1981, 17(8), 1351 - 89
{Transducing lambda phages with Escherichia coli genes}; Mindlin SZ et al.; The paper presents data on transducing lambdoid phages containing Escherichia coli genes . The major genetic techniques for isolating transducing phages (in vivo) are outlined . A combined table of best-studied transducing phages obtained by the methods of molecular genetics and genetic engineering lists phages genotype & basic literature references for the phages and their derivatives . The chromosome fragments of E . coli inserted in phage DNA are separately specified . Another table presents information about phages carrying E . coli fused operons and genes . The paper also provides detailed physical maps of three regions of the E . coli chromosome . The bibliography contains 300 items.

Mol Gen Genet, 1981, 182(1), 154 - 8
Fusion of the lac genes to the promotor for the cytidine deaminase gene of Escherichia coli K-12; Josephsen J et al.; Phage Mu has been inserted into the structural gene for cytidine deaminase (cdd) . By the use of phage lambda (lac, Mu) the promoter for the cdd gene has been fused to lacZ . In these strains lacZ expression is regulated by the cytR repressor protein and is therefore induced by cytidine . The fusion strains were used for the isolation of cddo mutants . Plaque forming lambda phages carrying the different cdd-lacZ fusions were isolated . Studies of the cdd-Mu strains showed that the cdd gene is transcribed clockwise with respect to the Escherichia coli map.

Drug Chem Toxicol, 1981, 4(1), 19 - 35
Genetic screening of compounds used in drug abuse treatment . III . LAAM; Brusick D et al.; Several compounds used clinically in drug abuse therapy were evaluated for genetic activity in a series of in vivo and in vitro assays . This third report in the series describes the results for one of these compounds, LAAM (L-alpha-acetyl methadol) . Previous reports described results from a three phase testing program for Naltrexone and Methadone . LAAM is related chemically to the narcotic analgesic oxymorphine, and is related chemically to a narcotic antagonist, naloxone . LAAM exhibited genetic activity in the ad-3 forward-mutation test in Neurospora crassa and also was weakly mutagenic in the mouse lymphoma forward-mutation assay . Further analysis of the ad-3 mutants from N . crassa indicated that they were the result of a parasexual phenomenon rather than forward mutation . There was one confirmed translocation carrier in the heritable translocation study, which by conservative interpretation might imply some germ-cell risk associated with exposure to LAAM.

Drug Chem Toxicol, 1981, 4(1), 1 - 18
Genetic screening of compounds used in drug abuse treatment . II . Methadone; Brusick D et al.; Several compounds used clinically in drug abuse therapy were evaluated for genetic activity in a series of in vivo and in vitro assays . The second report in this series describes the results for one of these compounds, Methadone . A previous report described the results for Naltrexone . Methadone is a synthetic narcotic analgesic used as a substitute for Heroin in drug detoxification programs . Methadone demonstrated weak activity in the E . coli DNa repair system and in the Neurospora crassa and the mouse lymphoma forward-mutation assays under the conditions of this evaluation . Additional analysis of the ad-3 mutants induced by a related compound, LAAM, in Neurospora indicated that they were the result of a parasexual phenomena rather than forward mutation . Therefore, the methadone-induced ad-3 mutants also may be due to a parasexual phenomena.

Aust J Biol Sci, 1981, 34(1), 125 - 32
Use of Cibacron Blue--Sepharose 6B to detect modifications of the non-allosteric 6-phosphofructokinase from Escherichia coli K-12; Ewings KN et al.; In crude cell-free extracts of aerobically grown E . coli K-12, the non-allosteric form of 6-phosphofructokinase has a tetrameric molecular weight 140 000 with a low affinity (less than 5%) for the blue dextran chromophore--Cibacron Blue . The allosteric form has the same tetrameric molecular weight, but possesses a strong affinity for the blue dextran chromophore . Under conditions of prolonged storage, purification procedures of mild heat treatment (50 degrees C), the non-allosteric form converts to an active dimer (mol . wt 67 000), which binds to Cibacron Blue (less than 90%) . Acid precipitation plus heat treatment prevents the conversion to the dimeric form and retains low Cibacron Blue affinity . These results are consistent with the isolation of a low molecular weight form and suggest that the inherent lability of this enzyme might be due to both non-specific proteolytic modification and a weak quaternary structure.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 69 - 73
Unique primed start of phage phi X174 DNA replication and mobility of the primosome in a direction opposite chain synthesis; Arai K et al.; A specific fragment of the phi X174 viral circle sustains the primed start of complementary DNA strand synthesis in vitro, even though the intact circle permits primed starts at many sites . The 300-nucleotide fragment from restriction nuclease digestion contains the recognition site for protein n', a DNA-dependent ATPase essential for priming phi X174 DNA replication . This n' recognition site contains within it a 44-nucleotide sequence with a potential hairpin structure and may be regarded as the starting signal for replication {Shlomai, J . & Kornberg, A . (1980) Proc . Natl . Acad . Sci . USA 77, 799-803} . After initiation on the 3' side of this sequence, the priming system (primosome) repeatedly generates primers by moving processively on the DNA template in a direction opposite to chain elongation . This primosome mobility is an attractive model for the discontinuous phase of Escherichia coli chromosome replication, in which processive primosome movement with the replicating fork is proposed for repeated initiations of nascent replication fragments.

Mol Gen Genet, 1981, 181(3), 379 - 83
Molecular cloning of menaquinone biosynthetic genes of Escherichia coli K12; Guest JR et al.; A transducing phage carrying some of the genes (men) defining the early stages of menaquinone biosynthesis was isolated from a pool of recombinant lambda phages that had been constructed from R.HindIII digests of E . coli DNA and the corresponding insertion vector . The lesions of menB and menC mutants were complemented by the phage but menD mutants were transduced either at low frequencies or not at all . This indicates that the transducing phage contains functional menB and menC genes but that only part of the menD gene had been cloned . The phage (lambda G68) was accordingly designated lambda menCB(D) . Studies with the transducing phage enabled earlier mapping data (Guest 1979) to be reinterpreted in favour of the gene order nalA....menC..menB..MenD....purF . Restriction analyses established the presence of a bacterial DNA fragment (11.5 kb) linked by a R.HindIII target to the right arm of the lambda genome but fused to the left arm of the vector . Hybridization studies confirmed that the cloned DNA was derived from a larger R.HindIII fragment (21 kb) . A physical map of the men region was constructed and some flanking and overlapping fragments were identified.

Gene, 1981 Jan-Feb, 13(1), 89 - 102
Sequence and properties of operator mutations in the bio operon of Escherichia coli; Barker DF et al.; The nucleotide-sequence changes occurring in newly isolated operator-constitutive mutations of the divergently transcribed bio operon have been determined . The observed point mutations are single GC leads to AT changes which occur at two symmetrical points in the hyphenated inverted repeat present in the control region . The changes at position -15 (with respect to the center of the inverted repeat) cause constitutivity of leftward operon expression and decreased expression of bioB, due to alteration of the -35 region of the rightward promoter . The change at position +15 is identical to one of the changes that Otsuka and Abelson (1978) detected in the bio p98 bio o34 double mutant . The location of the bio p131::IS1 insertion, which affects both leftward and rightward transcription, is also within the operator region . Both of the operator-constitutive mutations and the bio p131 insertion cause decreased repressor binding in vivo as shown by repressor titration tests on multicopy plasmids which bear them . The operator-constitutive mutations also decrease repressor binding in vitro, where added repressor fails to protect the TaqI site that is protected by repressor in bio o+ DNA . These results confirm several aspects of the model for bio operon regulation proposed by Otsuka and Abelson (1978).

Gene, 1981 Jan-Feb, 13(1), 47 - 55
Organization and transcription of the dnaA and dnaN genes of Escherichia coli; Sakakibara Y et al.; The locations of the linked dnaA and dnaN genes of Escherichia coli in a specialized transducing lambda phage genome have been determined by electron microscopic heteroduplex analysis, using phages with deletions or insertions in the dnaA or dnaN gene . The transcription initiation sites for the dna genes were also localized by electron microscopic analysis of DNA-RBA heteroduplex molecules formed between the E . coli DNA fragment of the phage genome and the in vitro transcription products of the fragment . The dnaN gene was found to be transcribed in the same direction as the dnaA gene, and predominantly from the promoter of the dnaA gene.

Genetika, 1981, 17(1), 52 - 9
{Low transfecting efficiency of phage lambda ring chromosomes and their fragments formed by membrane nucleases}; Drabkina LE et al.; Transfection efficiency of a number of lambda DNA samples differing in ring to linear molecules ratio was determined . Graphic extrapolation to the zero content of linear molecules showed that efficiency of ring molecules did not exceed 5% of that of linear molecules . Probably, this difference is caused by more fast penetration of linear molecules into the cell and, therefore, by lower probability of their degradation by cell wall nucleases . Fragments of both ring and linear molecules formed by cell wall nucleases proved to be inactive in marker rescue experiments.

Mutat Res, 1981 Jan, 80(1), 43 - 64
Mutagen sensitivities and mutator effects of MMS-sensitive mutants in Neurospora; Kafer E; 7 mus (mutagen-sensitive) mutants of Neurospora crassa, which are more sensitive to the toxic effects of MMS (methyl methanesulfonate) than wild-type, were investigated for cross-sensitivities to other mutagens and inhibitors . These mutants have recently been mapped in 5 new genes, mus-7 to mus-11, and mutant alleles from each gene were checked for their effects on mutation frequencies . It was found that mutants in 3 of these 5 genes showed radiation-induced mutation frequencies similar to wild-type . These included 2 alleles of the gene mus-10, which were cross-sensitive only to UV and were the only mutants that produced some viable ascospores in homozygous crosses . The mutant of the second gene, mus-8, was especially sensitive to UV and mitomycin C and produced slightly reduced frequencies of spontaneous mutation . In contrast, the mutant of the third gene, mus-7, was not UV-sensitive but showed some cross-sensitivity to X-rays; mus-7 was highly sensitive to MMS and also to histidine, which inhibits various repair-defective mutants at concentrations well below those that reduce wild-type growth . None of these mus resemble mutants previously found in Neurospora, nor do they conform clearly to mutant types identified in E . coli or yeast . On the other hand mutants in 2 further genes, mus-11, and especially 2 alleles of mus-9, are very similar to uvs-3 of Neurospora and generally resemble mutants that are considered to be defective in "error-prone" repair . They were UV- as well as X-ray-sensitive, and showed strong spontaneous mutator effects but almost no increase in recessive lethal frequencies in heterokaryons after UV-treatments.

Eur J Biochem, 1981 Jan, 113(2), 397 - 403
Appearance of elongation factor Tu in the outer membrane of sucrose-dependent spectinomycin-resistant mutants of Escherichia coli; Dombou M et al.; When sucrose-dependent spectinomycin-resistant (Sucd-Spcr) mutants of Escherichia coli were grown in the absence of sucrose, a new protein appeared in the membrane fraction insoluble in Triton X-100 . The protein had a hydrophobic nature . However, unlike other outer membrane proteins the new protein was extracted with sodium dodecyl sarcosinate . The new protein was found to be identical with elongation factor Tu (EF-Tu), as judged from the electrophoretic mobility in three different gel systems, coprecipitation with the antiserum against EF-Tu, the profiles of peptide fragments produced with three different proteases and analyses of N-terminal and C-terminal amino acids . This membrane EF-Tu accounted for 5-10% of total cell EF-Tu . When spheroplasts were pretreated with trypsin, EF-Tu in the outer membrane disappeared . Incubation of cytosol EF-Tu with the outer membrane did not result in the binding of EF-Tu to the membrane . These results indicate that the appearance of EF-Tu in the outer membrane is not due to artificial binding during membrane preparation . It is suggested that the ribosomal alteration resulted in dislocation of the cytosol protein into the outer membrane.

J Bacteriol, 1981 Jan, 145(1), 288 - 92
Deletion map of the Escherichia coli structural gene for alkaline phosphatase, phoA; Sarthy A et al.; Lambda transducing phages containing portions of the phoA gene have been isolated and used to construct a deletion map of the phoA gene . The isolation of a plaque-forming lambda transducing phage carrying the entire phoA gene is also described . Two new methods for screening or selection of mutants that have altered levels of alkaline phosphatase activity are reported.

J Bacteriol, 1981 Jan, 145(1), 200 - 10
Three genes coding for subunits of the membrane sector (F0) of the Escherichia coli adenosine triphosphatase complex; Downie JA et al.; Two mutant unc alleles, unc-469 and unc-476, have been characterized as affecting a previously undescribed gene, designated uncF . The uncF gene is part of the unc operon (with the gene order being uncBFEAGDC), although some uncertainty remains as to the relative order of the uncF and uncE genes . Mutant strains carrying the uncF469 or uncF476 allele lack the 18,000-molecular-weight component of the F0 sector of the adenosine triphosphatase in the cell membrane but retain the dicyclohexylcarbodiimide-binding protein (molecular weight, 8,400) . Conversely, strains carrying mutations in the uncE gene lack the dicyclohexylcarbodiimide-binding protein but retain the 18,000-molecular-weight protein in the cell membrane . Strains carrying mutations in the uncB gene have both the 18,000-molecular-weight protein and the dicyclohexylcarbodiimide-binding protein present in the cell membranes . The three proteins of the F0 portion of the adenosine triphosphatase, viz., 24,000, 18,000, and 8,400 molecular weights, became membrane associated after in vitro transcription-translation with plasmid pAN51 as template . Plasmids carrying deletions which affected the UncBFE region were isolated from plasmid pAN51 and characterized genetically . A comparison of the genes that were absent from the various deletion plasmids with the membrane-associated products formed after in vitro transcription-translation indicated that the uncB gene coded for the 24,000-molecular-weight protein and that the gene order was probably uncBFE . A correlation between length of deoxyribonucleic acid, genes present, and their products is presented in relation to plasmid pAN51.

Nature, 1981 Jan 1, 289(5793), 89 - 91
Escherichia coli ribosomal protein S8 feedback regulates part of spc operon; Dean D et al.; In Escherichia coli the genes coding for the 52 ribosomal proteins (r-proteins) are organized into a number of transcription units located at various regions on the bacterial genome . The expression of r-protein genes is balanced so that individual r-protein synthesis rates change coordinately in response to changing environmental conditions, and significant amounts of free r-proteins do not exist in the cellular pool . We have suggested a model for the balanced regulation of r-protein gene expression, namely that r-protein synthesis and ribosome assembly are coupled so that r-proteins not incorporated into ribosomes prevent the further translation of r-protein mRNA by a feedback regulatory mechanism . The model was tested in vitro by examining the effect of purified r-proteins on DNA directed r-protein synthesis, and in vivo by examining the effect of overproduction of certain r-proteins on the synthesis rates of other r-proteins . In vitro experiments have revealed that some r-proteins (L1, L4, L10, S4 and S8) can selectively inhibit the synthesis of r-proteins whose genes are in the same operon as their own, and that this specific feedback regulation occurs at the level of translation rather than at the level of transcription of mRNA . Regulatory roles for L1, S4 and L4 have also been established by in vivo experiments . We have studied further the feedback regulatory properties of S8 in vivo and in vitro, and report here that the protein regulates a part of the spc operon.

Acta Biol, 1981, 32(3-4), 275 - 82
Cloning of the mouse satellite DNA; Horvath P et al.; A stable recombinant clone was constructed by inserting a 1.5 kb mouse satellite DNA HindIII restriction fragment into the plasmid pBR-322 . The cloned fragment according to both hybridisation data and restriction analysis seems to be identical with the major component of the mouse satellite DNA . It contains two Atu4001 (EcoRII) monomers, one dimer and one "1.5-mer" . HindIII restriction sites are either in position around 95 or 140 of the Atu4001 monomer . Our results and the recently published prototype sequence of the mouse satellite DNA Sau961 monomer (15) suggest that HindIII cleavage of the mouse satellite DNA follows the B type restriction pattern.

J Mol Appl Genet, 1981, 1(3), 177 - 90
Construction and characterization of SV40 recombinants with beta-globin cDNA substitutions in their early regions; Southern PJ et al.; A cDNA segment coding for rabbit beta-globin has been inserted at different locations in the early region of simian virus 40 (SV40) . The inserted sequences in these recombinants are transcribed from the SV40 early region promoter, and the primary transcripts are processed to mature mRNAs using viral intervening sequences and the early region polyadenylation site . After infection with various recombinants, beta-globin polypeptide is synthesized only when the beta-globin translation initiation codon is the first AUG in the messenger RNA sequence . When the early region transcripts contain the beta-globin cDNA sequence 3-proximal to the small t antigen coding sequence, beta-globin synthesis is not detectable . However, these recombinants produce small t antigen and abbreviated forms of large T antigen.

Ann Rech Vet, 1981, 12(3), 259 - 63
{Incidence of rotavirus infection and in combined infection of rotavirus and enteropathogenic Escherichia coli in French calves (author's transl)}; Perrin B et al.; Detection of a rotavirus in faeces of 789 calves developing diarrhoea gave positive results among 48% of the calves . The same investigation extended to 96 apparently healthy animals shows that 12.5% of the faeces contained rotavirus . It appears that all the last ones cannot be considered as healthy controls . Association of rotavirus and E . coli K99+ is found in 5% of sick animals less than 10 days old.

Dev Biol Stand, 1981, 50, 293 - 300
Structure and expression of the hepatitis B virus genome; Wain-Hobson S et al.; By fusion of the hepatitis B virus (HBV) surface antigen (HBsAg) gene to that of the E . coli lac Z gene carried by a phage lambda derivative, expression of HBsAg antigenic determinants was obtained and carried by a 138,000 dalton fusion polypeptide . Such a protein could be ultimately useful for second generation vaccine production . HBsAg gene expression was studied in eukaryotic cells using the mouse L cell (tk-) system . Cotransformation using a plasmid carrying two copies of the HBV genome in a tandem, head-to-tail arrangement (pCP10) and the cloned HSV-1 tk gene resulted in the excretion of 22 nm HBsAg particles in the supernatant . No other HBV markers were detected . These particles possess the same characteristics as the human serum particles (morphology, diameter, density, antigenicity) . The purified HBsAg particles from L cells were found to be highly immunogenic in mice . HBV mRNA transcripts from these cells were analysed by Northern blotting . A major species of 2,300 bases was detected . This was mapped on the genome by hybridization with subgenomic fragments and in the L cell system using a series of plasmid derivatives carrying insertions at specific sites in the HBV genome and assaying for HBsAg expression . Thus the HBsAg gene promotor was localized between positions 2,400-2,800 . Indeed there is only one TATA like sequence in this region, starting at position 2,776.

Mol Biol (Mosk), 1981 Jan-Feb, 15(1), 79 - 85
{Modification of Escherichia coli RNA polymerase by diethylpyrocarbonate . II . Binding and unwinding of double-stranded DNA}; Rozovskaia TA et al.; E . coli DNA dependent RNA polymerase was modified by diethylpyrocarbonate . Binding to a double-stranded DNA and unwinding of the DNA at the enzyme binding site by the modified enzyme were examined . It was found that RNA polymerase reversibly lost the ability to unwind DNA helix as well as the RNA synthetic activity when 9 to 11 histidyl residues of the enzyme were modified . In addition ot modification of the most reactive sulfhydryl or amino groups of the enzyme accompanying histidyl residues modification results in irreversible decrease of the salt concentration which is necessary to remove the enzyme from DNA cellulose column . Further modification of the less reactive sulfhydryl or amino groups leads to irreversible loss of the DNA binding ability and to the enzyme structure alteration.

Mol Gen Genet, 1981, 184(3), 548 - 50
Internal promoters of the rpoBC operon of Escherichia coli; Ma JC et al.; Four ribosomal protein genes, rplA, rplJ, rplK and rplL form an operon in E . coli together with the genes rpoB and rpoC which encode the beta and beta' subunits of RNA polymerase . Transcription is initiated principally at two promoters, PL11 and Pl, the overall structure of the operon being (in the direction of transcription) PL11 rplK rplA Pl rplJ rplL rpoB rpoC . Here we describe studies of phage lambda derivatives carrying various segments of this operon, which demonstrate the existence of at least three additional weak internal promoters, and help to define their positions and strengths.

Mol Gen Genet, 1981, 184(3), 536 - 8
Primary structure of Escherichia coli RNA polymerase nucleotide substitution in the beta subunit gene of the rifampicin resistant rpoB255 mutant; Ovchinnikov YuA et al.; The transducing phage lambda dsupM814 and the plasmid pIB1830 containing the wild-type rpoB gene have been constructed and the primary structure of the gene's central fragment has been established . In contrast with the wild-type, the gene of the rpoB255 mutant, whose primary structure has been published, was found to contain an A.T . leads to T.A . transversion entailing the substitution of a valine residue for the aspartic acid residue (516) of the wild-type beta subunit.

Mol Gen Genet, 1981, 184(3), 508 - 18
Mapping of mglB, the structural gene of the galactose-binding protein of Escherichia coli; Boos W et al.; The tetracycline resistance transposon Tn10 was inserted into the E . coli chromosome near mglB550, a structural gene for the galactose-binding protein . P1 transductions established the position of these Tn10 insertions (zee-700, 701, 702::Tn10) close to the genes ptsF, fpk, cdd, mglB550, his, and gatA with 85%-95%, 85%, 36%, 20%-40%, 12%-15%, and 0.5% cotransduction frequency . Three factor crosses revealed the relative sequence of the genes as: mglB550, zee-700::Tn10, ptsF, fpk, cdd, his, gatA was found to be 1.3% cotransducible with mglB550 . Two Tn10 insertions near gatA were isolated and characterized . One, zef-704::Tn10, was 3% cotransducible with fpk, 8% with mglB550, and 42% with gatA . The other, zef-703::Tn10, was 98% cotransducible with gatA but not with mglB550 or fpk . Neither of these two Tn10 insertions was cotransducible with cdd . Four factor crosses revealed the sequence gatA, zef-704::Tn10, mglB550, fpk . Neither zee-700::Tn10 nor zef-703::Tn10 showed an (0/300) cotransduction with either glpT or gyrA . The clockwise order of genes is then: his, cdd, fpk, ptsF, zee-700::Tn10, mglB550, zef-704::Tn10, gatA . With a fix-point for his at 44 min, fpk would be placed at 45 min and mglB550 at 45.5 min . During the course of this work we noticed that the cotransduction frequency between Tn10 insertions and nearby markers tended to increase when new P1 lysates were prepared from freshly reisolated strains . This may indicate loss of nonessential genes adjacent to Tn10 insertions . Using insertion zee-703::Tn10, we isolated deletions extending into an mgl gene other than mglB . Crosses between such a deletion mutant and an mglB550 mutant were done . The analysis of the periplasmic proteins of these as well as other transductants or recombinants involving the mglB550 or the mglB551 gene revealed the existence of strains synthesizing both the wild-type as well as the corresponding mutant protein . Strains containing both proteins exhibit either wild-type or mutant phenotype . These strains appeared unstable . Upon reisolation from purified stock cultures kept in glycerol at -20 degrees C, colonies could be isolated that carried only mutant or wild-type protein.

Mol Gen Genet, 1981, 184(3), 430 - 3
Molecular cloning of the tolC locus of Escherichia coli K-12 with the use of transposon Tn10; Morona R et al.; We have cloned the tolC gene of E . coli K-12 into pSF2124 by using transposon Tn10 as the marker to first isolate the relevant DNA fragment . The gene is on a 10.5 kb EcoRI fragment, and Tn5 insertion mutagenesis locates the gene near one end of this EcoRI fragment . An EcoRI-PstI fragment has been subcloned into pBR322 to facilitate further analysis of the gene.

Mol Gen Genet, 1981, 184(3), 364 - 71
A fine structure map of spontaneous and induced mutations in the lambda repressor gene, including insertions of IS elements; Lieb M; Mutations at over 70 sites in the cI gene have been mapped by 4-factor crosses and assigned precise or approximate positions in the DNA sequence . 16 of 25 spontaneous mutations were insertions of IS1, IS3 or IS5 into AT-rich regions of cI . The 5-methylcytosine in the sequence Cm5CAGG is a hot spot for spontaneous cI amber mutations . Recombination frequencies between mutations were proportional to distance with the exception of amber mutations at 4 sites, including the host spot for spontaneous mutations . Mutations with a given phenotype are clustered on the genetic map . No missense mutations affecting repressor activity were found in the central one-third of cI, but 5 of 6 ind- mutations were located in this region . The amino-terminal third of the gene contains the sites of most trans-dominant cI- mutations, and of all ts mutations that result in repressors that are reversibly inactivated at high temperatures.

Mol Gen Genet, 1981, 184(1), 87 - 91
The tnpR gene product of TnA is required for transposition immunity; Wallace LJ et al.; A mutant of TnA no longer recognizing immune plasmids had been isolated . The mutation is complemented in trans by a functional tnpR gene . The requirement for wild type tnpR gene product for the establishment of transposition immunity was confirmed by the use of a derivative of transposon Tn3 in which both the tnpA and the tnpR genes are partly deleted . This deleted Tn3 was shown to transpose onto an immune plasmid in the presence of a wild type tnpA gene but not in the presence of both tnpA and tnpR genes.

Mol Gen Genet, 1981, 184(1), 33 - 9
The nucleotide sequence of the atp genes coding for the F0 subunits a, b, c and the F1 subunit delta of the membrane bound ATP synthase of Escherichia coli; Nielsen J et al.; The nucleotide sequence has been determined of a 2,500 base pair segment of the E . coli chromosome located between 3.75 and 6.25 kb counterclockwise of the origin of replication at 83.5 min . The sequence contains the atp genes coding for subunits a-, b-, c-, delta- and part of the alpha-subunit of the membrane bound ATP synthase . The precise start positions of the atpE (c), atpF (b), atpH (delta) and atpA (alpha) genes have been defined by comparison of the potential coding sequences with the known amino acid sequence of the c-subunit and the determined N-terminal amino acid sequences of the respective subunits . The genes are expressed in the counterclockwise direction . Their order (counterclockwise) is: atpB (a), atpE (c), atpF (b), atpH (delta) and atpA(alpha) . The coding sequences for subunits b and delta yield polypeptides of 156 and 177 amino acids, respectively, in accordance with the established sizes of these subunits; the one for the c-subunit, the DCCD binding protein, fits perfectly with its known sequence of 79 amino acids . The a-subunit is comprised within a coding sequence yielding a polypeptide of 271 amino acids . It is suggested, however, that the a-subunit (atpB) contains only 201 amino acids, in accordance with its known size, starting from a translation initiation site within the larger coding sequence . The stoichiometry of the F0 sector subunits is discussed and a model is proposed for the functioning of the highly charged b-subunit of the F0 sector as the actual proton conductor.

Mol Gen Genet, 1981, 184(1), 121 - 4
Maintenance and genetic stability of vector plasmids pBR322 and pBR325 in Escherichia coli K12 strains grown in a chemostat; Noack D et al.; The maintenance and genetic stability of the vector plasmids pBR322 and pBR325 in two genetically different Escherichia coli hosts were studied during chemostat cultivation with glucose and ammonium chloride limitation and at two different dilution rates . The plasmid pBR322 was stably maintained under all growth conditions tested . However pBR325 segregated from both hosts preferentially during glucose limitation and at low dilution rate . In addition to this general segregation process a separate loss of tetracycline resistance was observed . The remaining plasmid conferred resistance to ampicillin and chloramphenicol only, without any remarkable alteration of its molecular weight . Cultivation conditions in the chemostat were found that allowed the stable genetic inheritance of both plasmids in the hosts studied.

Mol Gen Genet, 1981, 183(3), 497 - 504
Physical mapping of the srl recA region of Escherichia coli: analysis of Tn10 generated insertions and deletions; Willis DK et al.; A restriction endonuclease map for the enzymes EcoRI, BamHI, SalI, and PstI covering 23.5 kilobase pairs (kb) of the srl recA region of Escherichia coli was constructed . An insertion of the transposon Tn10 in the negative regulatory gene srlR was shown to be located 5.8 kb away from the promoter proximal end of the recA gene . The extent of several Tn10 generated deletions, originating from the srlR301::Tn10 insertion, were analyzed by physical mapping . Three mutations that had removed the Tn10 encoded tetracycline resistance gene, del(srl-recA)302, del(srl-recA)304, and del(srl-recA)303, were found to be deleted for 40%, 45%, and 50% of the recA structural gene, respectively . A deletion, del(srl-recA)306, that had not affected the structure of the Tn10 in srlR301 was shown to have removed the entire recA structural gene.

Prog Clin Biol Res, 1981, 64, 139 - 50
Interactions between the maturation protein gp17 and the single-stranded DNA binding protein gp32 initiate DNA packaging and compete with initiation of secondary DNA replication forks in phage T4; Mosig G et al.; Since T4 DNA, which is being packaged is actively replicating and recombining, we have asked whether replication and recombination proteins interact with maturation proteins . We report here on genetic evidence for interaction of the single-stranded DNA binding protein gp32 with the maturation protein gp17 . Based on these and other results we suggest a model in which DNA packaging is initiated from recombinational intermediates.U

Mol Gen Genet, 1981, 184(2), 300 - 7
A new type of IS1-mediated deletion; Sommer H et al.; Genetical tests and DNA sequence analysis revealed that the mechanism of formation of IS1-induced type I and type II deletions differs . IS1-mediated type II deletions occur at the termini of the integrated element and do not remove the element . This process is independent of the cellular recA system and does not involve DNA sequence homology . Conversely, the formation of IS1-induced type I deletions differs substantially . They require recA gene product, small DNA sequence duplications and a topological arrangement of the DNA molecule to allow alignment of duplications.

Mol Gen Genet, 1981, 184(2), 241 - 8
Transposon Tn951 (TnLac) is defective and related to Tn3; Cornelis G et al.; Tn951 is flanked by two perfect inverted repeats of 41 bp which include the 38 bp sequence of the IR of Tn3 . Tn951 also contains the last 100 bp of the tnpA gene but with at least two mutations . However, beyond nucleotide 137 the sequences diverge and hybridization experiments show that Tn951 lacks at least the first two thirds of the tnpA gene . In agreement with these observations Tn951 does not transpose by itself at a detectable frequency but can be complemented by the tnpA gene of Tn801 or Tn3 . Tn501, Tn1721 and gamma delta do not complement Tn951 transposition . Transposition of Tn951 duplicates 5 bp of target DNA sequence.

Mol Gen Genet, 1981, 184(2), 208 - 12
P1 transduction map spanning the replication terminus of Escherichia coli K12; Bitner RM et al.; The region of the E . coli chromosome that contains the replication terminus has not previously been spanned by P1 cotransduction . We have used Tn5, Tn9 and Tn10 transposons inserted in this region as genetic markers, and have constructed a genetic map that extends from fnr (min 29.3) to manA (min 35.7) . The relevant transposons that have been mapped in this region and which are described in this report are trg-1::Tn5 (min 31.1), zdc-235::Tn10 (min 32.3), zdd-230::Tn9 (min 33.3), and zde-234::Tn10 (min 34.2) . The size of this region as determined by P1 cotransduction is very similar to previous estimates obtained by bacterial conjugation.

Mol Gen Genet, 1981, 184(2), 191 - 9
Molecular cloning of the uvrD gene of Escherichia coli that controls ultraviolet sensitivity and spontaneous mutation frequency; Oeda K et al.; The uvrD gene of Escherichia coli that controls UV sensitivity and spontaneous mutation frequency has been cloned with phage lambda as vector . The increased sensitivity to ultraviolet light (UV) of uvrD3, uvrE502, recL152, and pdeB41 mutants, high mutability of uvrD3 and pdeB41 mutants, and conditional lethality of strain TS41 that carried pdeB41, polA1, and supl26 mutations were all suppressed by lysogenization of the mutant cells with lambda uvrD+ . These results were consistent with the idea that the uvrD, uvrE, recL, and pdeB mutations are alleles of the uvrD gene . In addition to the uvrD gene, lambda uvrD+ carried the corA gene that controls transport of Mg++, Mn++, and Co++ through the cell membrane . Hybrid plasmids carrying both uvrD and corA genes were also constructed by using pKY2289 as a cloning vehicle . Orientational isomers that carried the same 12.0 kb fragment in the opposite direction were equally efficient in complementing the UvrD- as well as CorA- defects of the transformed host cells, suggesting that the DNA insert contains all the genetic signals needed to express the two gene products . Insertion of the gamma delta sequence into recombinant plasmids was performed to generate appropriate restriction endonuclease target sites in the cloned DNA fragments.

Mol Gen Genet, 1981, 183(2), 348 - 55
Variable expression of the ssb--1 allele in different strains of Escherichia coli K12 and B: differential suppression of its effects on DNA replication, DNA repair and ultraviolet mutagenesis; Lieberman HB et al.; We have transduced the mutant allele ssb-1, which encodes a temperature-sensitive single-strand DNA binding protein (SSB), into several Escherichia coli strains, and have examined colony-forming ability, DNA replication, sensitivity to ultraviolet light (UV) and UV-induced mutability at the nonpermissive temperature . We have found: 1) that the degree of ssb-1-mediated temperature-sensitivity of colony-forming ability and of DNA replication is strain-dependent, resulting in plating efficiencies at 42 degrees C (relative to 30 degrees C) ranging from 100% to 0.002%; 2) that complete suppression of the temperature-sensitivity caused by ssb-1 occurs only on nutrient agar, and not in any other medium tested; 3) that strains in which ssb-1-mediated temperature-sensitivity is completely suppressed show moderate UV sensitivity and normal UV mutability at 30 degrees C, but much more extreme UV sensitivity and drastically reduced UV mutability at 42 degrees C; and 4) that defects in excision repair or in other Uvr+-dependent processes are not responsible for most of the UV sensitivity promoted by ssb-1 . We discuss our results in relation to the known properties of SSB and its possible role in the induction of DNA damage-inducible (SOS) functions.

Mol Gen Genet, 1981, 183(2), 333 - 40
Isolation and properties of Tn10 insertions in the rac locus of Escherichia coli; Binding R et al.; Two Tn10 insertions that are in the rac locus of the chromosome of Escherichia coli have been isolated and characterized . The insertions are located at min 29.7 and min 30.0 . The insertions are stable when an F123 rac::Tn10 episome is transferred to an F- rac+ recipient, but they are lost at a high frequency when transferred to an F- rac- recipient . This latter condition has been previously demonstrated to cause the excision of the rac locus . The Tn10 insertions are also lost at a high frequency when strains containing them are lysogenized with lambda reverse . If the lysogens that have lost the Tn10 insertion are subsequently cured of lambda reverse, the cells no longer contain sequences homologous with rac locus DNA . These strains were rac- when tested for recombination activation (Low 1973), and this procedure consequently provides a simple means to make isogenic rac+ and rac- strains.

Mol Gen Genet, 1981, 183(1), 45 - 50
Integration specificity of an artificial kanamycin transposon constructed by the in vitro insertion of an internal Tn5 fragment into IS2; Saint-Girons I et al.; IS2 has been marked genetically by the in vitro insertion into its HindIII site of a 3.3 Kb HindIII fragment of Tn5 conferring resistance to kanamycin . The transposition of the IS2::Km, thus obtained, to lambda has been found and insertion sites were characterised . Each of ten independent IS2::Km insertions were found at the same site at 61.2% of the lambda map, always in the same orientation (orientation II relative to the xis gene) . The integration sites of IS2::Km in five of the kanamycin-transducing phages were determined by DNA sequence analysis, and were found to be identical at the nucleotide level . Further transposition of IS2::Km from lambda to the bacterial chromosome was demonstrated.

Mol Gen Genet, 1981, 183(1), 192 - 6
Recombinational instability of F' plasmids in Escherichia coli K-12: localization of fre-sites; Bresler SE et al.; The F' plasmids ORF-1 (purE+ tsxs proC+ lac+) and F'14 (argE+ metB+ ilv+) contain active regions of recombination, fre I and fre II correspondingly . The plasmid ORF-1 is stable in recF- cells (i.e., with the RecBC pathway of recombination) and decays in rec+ cells (RecBCF pathway) giving two types of product: F+ and plasmid pCK-1 (tsxs proC+ lac+) containing part of the initial DNA . They are extremely instable in the presence of the RecF pathway, (recBC- sbcB-), yielding F+ and plasmid pCK-2 (proC+ lac+) . The instability of plasmids depends on a region of homology between the chromosome and the episome . The instability of ORF-1 shows the participation of IS3 elements (alpha 1 beta 3 and alpha 3 beta 1) in the recA, recF-dependent recombinational decay and allows localization of two active sites on the chromosome: fre I1 between purE and tsx markers and fre I2 between tsx and proC . The plasmid F'14, in accordance with published data, is able to yield F+ cells by recA-independent recombination . But eventually this plasmid may undergo a recA, recF-dependent decay . Genetic analysis of these events allows localization of an active point of recombination, freII1, between argE and metB . Another active point is localized inside the F factor . The recA-dependent decay of plasmid F-14 is also excluded on the RecBC pathway (recF- strains).

Mol Gen Genet, 1981, 183(1), 134 - 8
Essential role of the gyrB gene product in the transcriptional event coupled to dnaA-dependent initiation of Escherichia coli chromosome replication; Filutowicz M et al.; When a culture of the gyrB41-ts mutant is shifted to the nonpermissive temperature, DNA synthesis is arrested at the initiation phase of chromosome replication . After thermal inactivation of the gyrB gene product reinitiation occurs in the presence of chloramphenicol but not in the presence of rifampicin . This suggests that the B subunit of DNA gyrase may regulate synthesis of an "initiator RNA" . An rpoB202 mutation has been isolated which suppresses both the DnaA-initiation phenotype and the inhibitory action of antibiotics which are known to result in relaxation of chromosomal DNA in vivo . We propose that DNA tertiary structure rather than DNA gyrase itself plays an essential regulatory function in the dnaA-dependent transcription which precedes the initiation of chromosome replication.

Bull Pan Am Health Organ, 1981, 15(4), 318 - 25
Etiology of childhood diarrhea and oral rehydration therapy in northeastern Brazil; McLean M et al.; PIP: This study was conducted from January 1977 to June 1978 in Fortaleza, Brazil, to evaluate the oral rehydration treatment recommended by the World Health Organization for children admitted with acute diarrhea; admission peaked in January-March of both years and children treated came from the lowest socioeconomic strata of the popultion . Initial treatment consisted of intravenous administration of normal saline or 5% glucose with saline solution; intravenous therapy was continued until objective signs of improvement were evident . Of the 53 children observed 24 continued with intravenous therapy, and 29 were administered oral rehydration therapy with a glucose-electrolyte solution containing 90 milliequivalent per liter of sodium ion . Mean age in the intravenous and in the oral groups were 10 and 8 months, respectively . The major symptoms were feverishness and vomiting . Stools from 37 patients were examined for disease agents; enterotoxigenic E . coli were identified in stools from 27% of these patients; ST-producing E . coli in 21.6%, and LT-producing E . coli in the remaining 5.4% . During the initial rehydration period there were no significant differences between the 2 groups as to duration of therapy or amount of fluid given . During the subsequent study period members of the oral treatment group required significantly less fluid and less treatment than members of the intravenous group, average amount of fluid required per kg of body weight being 67.3 ml in the intravenous group, and 32.3 ml in the oral group . Progress toward a normal level of consciousness was significantly greater among members of the oral rehydration group; the mothers of the children were able to administer the oral therapy quite effectively, thus saving time for physicians and nurses .

Acta Biol Med Ger, 1981, 40(4-5), 505 - 10
Molecular cloning of DNA sequences coding for mouse embryonic globins; Fantoni A et al.; Yolk sac derived erythroid cells in mouse embryos synthesize four embryonic globins of which two are alpha-like and two are beta-like . Pure globin messenger RNAs from these cells were used as templates for two successive polymerizing reactions and a mixture of double stranded cDNAs coding for the four globins was obtained . These molecules were blunt-end ligated to an ECoR1 digested pBR322 plasmid and the recombinant plasmids were used to transform E . coli Hb101 . Bacterial clones which proved positive upon hybridization with 32P-labelled embryonic globin cDNA were amplified and their plasmid DNA was isolated . Three different plasmids were studied, namely no . 2, 16 and 54 . The restriction map of these plasmids showed that: 1) plasmid no . 2 and 54 had lost extensive DNA sequences comprising the genes responsible for tetracycline resistance; 2) the size of inserted sequences ranges from 427 base pairs of plasmid no . 16 to about 280 base pairs of plasmid no . 54; 3) plasmid no . 2 does not share any of the studied restriction sites with the other plasmids, while no . 2 and 54 have at least one site in common . The coding properties of inserted DNA were determined by positive hybrid translation showing that no . 2 codes for the alpha-like embryonic chain x, while no . 16 and 54 code for a beta-like embryonic chain, either y or z.

Mol Gen Genet, 1981, 182(3), 520 - 2
pED100, a conjugative F plasmid derivative without insertion sequences; Willetts N et al.; The largest HindIII fragment of F includes the entire replication and transfer regions, and its circularisation with ligase gave the conjugative plasmid pED100 . This plasmid, which contains none of the F insertion sequences, was essentially unable to mobilise the E . coli chromosome or to give integrative suppression of a dnaA strain.

Mol Gen Genet, 1981, 182(3), 498 - 501
Identification of the nusB gene product of Escherichia coli; Strauch M et al.; Escherichia coli nusB mutants fail to support the activity of a phage lambda gene product, pN, which regulates phage gene expression by influencing transcription termination . We report the identification of the nusB protein on SDS-polyacrylamide gels as a 14,500 dalton protein.

Mol Gen Genet, 1981, 182(3), 462 - 70
Genetical and structural analysis of a group of lambda ilv and lambda rho transducing phages; Uzan M et al.; Eight lambda ilv C transducing phages generated from E . coli K12 secondary site lysogens have been analysed genetically and physically . Two of them carry, in addition, the rho gene and its promotor region, but not the cya gene . The ilv O 603 mutation has been located between ilv G and ilv E . Electrophoretic analysis of the proteins synthesized by these phages in a system of UV irradiated cells allowed us to assign molecular weights of 55000 and 66000 daltons to the ilv C and the ilv D gene products, respectively, and to show that an ilv G-encoded polypeptide of 60000 daltons is made from an ilv O- but not from an ilv O+ phage . The expression of the ilv G gene is discussed in the light of the recent finding of a promoter-attenuator region lying upstream to ilv G . Finally, we have found that one of the lambda ilv phages does not have the classical structure of a transducing phage.

Genetika, 1981, 17(9), 1555 - 65
{Genetic control of plasmid R6K conjugativity}; Abalakina EG et al.; The regions determining conjugation ability of plasmid R6K were localized by means of deletion mutants obtained in vitro and in vivo and Tra- mutants induced by integration of transposons Tn5, Tn7 and Tn9 into different DNA sites of the conjugative deletion mutant pAS3 . At least 13 genes were found to be involved in the genetic control of R6K conjugativity, on the basis of genetic, restriction and heteroduplex studies . They were mapped within the two DNA regions having the total molecular weight of about 10-11 md . A transposon-like structure with a replication function has been located between them.

Mol Gen Genet, 1981, 182(2), 268 - 72
Restriction endonuclease cleavage map of pKM101: relationship to parental plasmid R46; Langer PJ et al.; A detailed restriction endonuclease cleavage map of the plasmid pKM101 has been constructed . pKM101 plasmids containing individual Tn5 insertions were used to facilitate the ordering of restriction fragments generated by enzymes cleaving pKM101 at multiple sites . By restriction enzyme analysis, pKM101 (35.4 kilobases) appears to have arisen from its clinically-isolated parent by deletion of a single DNA region which codes for three of the four drug resistances carried by R46.

Mol Gen Genet, 1981, 182(2), 183 - 8
An IS4-encoded protein is synthesized in minicells; Trinks K et al.; A protein of Mr 47,000 is synthesized in Escherichia coli minicells, when these harbor a multicopy plasmid carrying IS4 in either orientation and between different flanking sequences . The protein corresponds to the sequence predicted from the known DNA sequence of IS4, as shown by partial N-terminal radiolabel protein sequence analysis . Its apparent molecular weight, however, as determined from its electrophoretic mobility in SDS polyacrylamide gels, is smaller than predicted . When compared with other plasmid-encoded proteins, the IS4-encoded protein is synthesized in minicells in small amounts . Its synthesis has not been detected in a DNA-dependent cell-free system.

J Nutr Sci Vitaminol (Tokyo), 1981, 27(3), 177 - 91
Role of pyridoxal kinase in vitamin B6 uptake by Escherichia coli; Yamada R et al.; Escherichia coli KG980, a vitamin B6 auxotroph derived from wild strain K12, concentrated exogenous pyridoxal in an energy-dependent manner, and the effects of energy sources and inhibitors on pyridoxal uptake, compared with those on proline uptake indicated that the energy required was in the form of phosphate bonds and not of membrane potential . The vitamin taken up was primarily present as pyridoxal 5'-phosphate and pyridoxamine 5'-phosphate intracellularly, and energy depletion decreased the accumulation as the phosphorylated derivatives but not as unaltered pyridoxal itself . This finding suggested that the intracellular phosphorylation, which was known to require ATP, was essential for the concentrative uptake of the vitamin . The suggestion was confirmed by the following evidence . 1) Pyridoxal oxime inhibited pyridoxal uptake by decreasing the intracellular phosphorylation without affecting the entry of pyridoxal across the cell membrane . 2) A pyridoxal-kinase deficient mutant (HN1) derived from the strain KG980 showed a low ability to take up pyridoxal because of the failure to accumulate it effectively as phosphorylated derivatives . The carrier-mediated nature of pyridoxal uptake, previously suggested by saturation kinetics, was further supported by the present finding that 4'-deoxypyridoxine inhibited pyridoxal uptake competitively, decreasing the intracellular appearance of unmetabolized pyridoxal . It is therefore most likely that pyridoxal enters the cells by facilitated diffusion and is accumulated by conversion to phosphorylated derivatives . Similar results on the uptake of pyridoxine and pyridoxamine are also presented.

Folia Microbiol (Praha), 1981, 26(4), 265 - 9
Catabolite repression of different inducible enzymes in Escherichia coli and the effect of cAMP; Jiresova M et al.; Simultaneous induction of two enzymes sensitive to catabolite repression does not lead to an additive decrease of the specific activity of the two . Exogenously added cAMP increases the specific activity of catabolically repressed enzymes, irrespective of whether the enzyme is induced separately or simultaneously with another enzyme . In the presence of 12 different substrates metabolized by inducible enzymes glucose does not bring about catabolite repression . Synthesis of cAMP is identical with that occurring under conditions when glucose brings about catabolite repression.

Circ Shock, 1981, 8(5), 585 - 600
Early cellular responses in vitro to endotoxin administration; Kilpatrich-Smith L et al.; The sequence of early events which follow the administration of E coli lipopolysaccharide (LPS) to cultured mouse neuroblastoma (C-1300) cells was investigated . Emphasis was placed on cellular energy metabolism in order to establish whether or not an energy failure occurred and whether it was a primary or a secondary effect . Exposure of cultured neuroblastoma cells to LPS produced rapid changes in the regulatory parameters of energy metabolism, an oxidation of intramitochondrial pyridine nucleotides, and a decline in cellular {ATP}/{ADP} {Pi}, which were followed by alterations in mitochondrial morphology . In spite of the changes in individual parameters at early stages of exposure to LPS, the cellular energy producing systems remained tightly controlled and the rate of ATP synthesis was maintained at a constant and undiminished level . This allowed the cells to preserve their ionic gradients as manifested by high intracellular {K+} and unaltered transmembrane electrical and pH gradients . These early changes in mitochondrial metabolism were not accompanied by detectable leakage of mitochondrial matrix enzymes into the cytosol, which indicated that mitochondrial membrane remained intact . After longer exposure to LPS, the rate of ATP synthesis declined, the mitochondrial membrane became permeable to high molecular weight substances (matrix enzymes), and intracellular {K+} began to decrease (K+ leakage) . It was concluded that responses of mitochondrial metabolism are one of the early events in endotoxemia.

Biosci Rep, 1981 Jan, 1(1), 53 - 60
Stimulation of Escherichia coli adenylate cyclase by lactose in strains carrying mutations in lactose permease; Peterkofsky A et al.; When a wild-type strain of Escherichia coli contains lactose permease, the accumulation of cyclic AMP (cAMP) by intact cells is inhibited by lactose . This inhibitory effect of lactose is observed in a strain with a mutant cAMP phosphodiesterase and therefore involves a regulation of adenylate cyclase activity . Some E . coli strains carrying mutations in lactose permease show an effect opposite to that of the wild-type strain; the accumulation of cAMP by intact cells is stimulated by lactose, but only when the mutant permease is present . Insertion of lactose permease into the membrane of cells can produce a change in the specific activity of adenylate cyclase; induction of the wild-type transporter is correlated with a decrease in the specific activity, while implantation of a mutant form of lactose permease can lead to an increase in the specific activity . From these data, it is suggested that the state of the lactose transporter in the cell membrane influences the activity of adenylate cyclase.

Adv Cyclic Nucleotide Res, 1981, 14, 215 - 28
Escherichia coli adenylate cyclase as a sensor of sugar transport function; Peterkofsky A; Adenylate cyclase of E . coli is a membrane-bound enzyme the function of which is to synthesize a cofactor for processes that are important in metabolic transitions . The depletion from the environment of a supply of a preferred carbon source dictates the requirement for initiating the synthesis of a new metabolic system; this synthesis will require cAMP . After the adaptation period, the requirement for a high level of synthesis diminishes, resulting in a diminished requirement for cAMP . A mechanism for regulating the activity of adenylate cyclase accomplishes the variation in the required cellular cAMP concentrations . In the absence of a transportable carbon source, adenylate cyclase activity is activated by cellular regulators; when carbon sources are transported, the cellular activators are dissipated, resulting in inhibition of adenylate cyclase activity . This scheme is summarized in Fig . 6 . Sugar transport systems fall into two categories: one in which the energy for the process comes from PEP (the PTS) and one in which the energy comes from the proton electrochemical gradient . Adenylate cyclase communicates with both of these systems by interacting with intermediates on the pathway to energy generation for driving these two transport processes . Adenylate cyclase couples indirectly to a large array of sugar-specific transport systems by interacting with intermediates common to all the processes . The net result of this regulatory mechanism is that, without physically communicating with the extracellular environment by spanning the membrane, adenylate cyclase effectively senses the presence of external sugars that interact with cells that have become competent to transport them.

Mol Gen Genet, 1981, 181(2), 222 - 9
Mapping of IS1 elements flanking the argF gene region on the Escherichia coli K-12 chromosome; Hu M et al.; Two directly-repeated IS1 elements have been mapped on the Escherichia coli K-12 chromosome at positions 23.2 kb and 34.5 kb counterclockwise of the IS3 element alpha3beta3 by using F-prime plasmids (including the F lac- proAB+ plasmid F128) that carry different portions of the bacterial chromosome in the purE to proA region . Mapping was accomplished in part by construction of EcoRI, BamHI, and BglII restriction enzyme cleavage maps . Electron microscope heteroduplex and hybridization studies indicate that the chromosomal region flanked by these IS1 elements is completely homologous to the IS1-argF-IS1 region (Tn2901) on the P1argF5 transducing phage (York and Stodolsky, 1981), which suggests that the argF gene region in the usual E . coli K-12 strains has a transposon-like structure.

Mol Gen Genet, 1981, 181(2), 183 - 91
The structure of R1drd19: a revised physical map of the plasmid; Clerget M et al.; We have analyzed derivatives of the plasmid R1drd19 carrying the transposon Tn10 by electron microscopy following denaturation and renaturation of the molecules, and by digestion with various restriction enzymes, gel electrophoresis and Southern blotting . We show: 1) that the published restriction map of R1drd19 is inconsistent with our results . We present a modified map which is consistent with our data . 2) that R1drd19 carries a single resident copy of the element IS10 which is normally associated with Tn10 as an inverted repeat, and 3) that R1drd19 carries three copies of the insertion element IS1 in the resistance determinant region.

Mol Gen Genet, 1981, 181(2), 169 - 75
The sequence of IS4; Klaer R et al.; IS-elements are devoid of easily recognizable transacting functions and exert their visible effects in the position cis only (recent reviews Calos and Miller 1980; Starlinger 1980) . It has been a matter of debate, whether these elements encode functions for their own transposition . In the case of the E . coli IS-elements this could not easily be determined by genetic methods, because most of these elements are present in several copies (Saedler and Heiss 1973; Deonier et al . 1979) . In the case of the IS-elements flanking transposons, evidence has recently been brought forward that these carry the transposition specificity (Rothstein et al . 1980; Kleckner 1980; Grindley 1981) . IS4 is present in one copy only in several E . coli K12 strains and should, therefore, be suitable for genetic and physiological studies (Chadwell et al . 1979) . It has been cloned from several sites on the E . coli chromosome in pBR322 (Klaer and Starlinger 1980) . Here we report the DNA sequence of IS4 which contains an open reading frame for 442 amino acids, and of the junctions of this element with surrounding DNA at three different sites in the E . coli chromosome.

Genetika, 1981, 17(7), 1205 - 10
{In vivo restriction of Escherichia coli-transforming DNA by endonuclease R.M.EcoRI}; Aleshkin GI et al.; Transformation of Escherichia coli K-12 for various chromosomal markers was accomplished by using AB1157 recBC+ strain as a recipient . The yield of transformants was reduced 10-fold, as compared with that obtained in JC7623 recBC sbcB recipient . Elimination of transformation has been obtained for arg, pro, his markers in AB1157 (pSA14) harbouring the R.M.EcoRI coding plasmid . Production of restriction endonuclease in this strain did not affect the efficiency of transformation for thr, leu markers . The presence of pSA25 which is isogenic to pSA14 but devoid of R.M.EcoRI genes has been irrelevant to transformation for leu, arg, pro, his, thr markers . Correlation between the restriction of transformed markers in vivo and in vitro is discussed.

Avian Dis, 1981 Jan-Mar, 25(1), 228 - 41
Improved performance of progeny of broiler parent chickens vaccinated with infectious bursal disease oil-emulsion vaccine; Wyeth PJ et al.; Field trials were conducted on nine broiler chicken flocks, which were the progeny of parents vaccinated with inactivated infectious bursal disease (IBD) oil-emulsion vaccine (OEV) . The average increase in overall weight gains was 7.97% of weight gains of similar birds from live-vaccinated parents . Food-conversion ratios (FCR) were calculated for five of the trials . The average improvement in FCR over that of the control chickens was 2.89% . Every broiler flock contracted subclinical IBD, but there was no significant difference in overall mortality rates, except in one trial . In that trial, inclusion body hepatitis and Escherichia coli septicemia in the progeny of the parents that received only live vaccines caused increased mortality . Weekly monitoring of IBD antibodies in two of the trials showed that, in one trial, maternally derived antibody (MDA) persisted in the test chicks until at least 22 days of age and in the controls until at least day 15 . In the other trial, MDA persisted until at least day 15 and day 8, respectively, in the test and control flocks . Field IBD challenge occurred at about day 30 and day 37 in the control and test chicks, respectively, in one trial and on day 17 and day 30 in the other . Overall weight gains and FCRs were not related to stocking densities.

Mol Gen Genet, 1981, 182(1), 95 - 8
DNA replication intermediates synthesized by lysates of dnaB, dnaG and dnaB dnaG mutants in vitro; Sclafani RA et al.; Isogenic dnaB, dnaG, and dnaB dnaG mutants were constructed and used as extracts in the cellophane-disc in vitro DNA replication system . The increased proportion of 5S DNA characteristics of the dnab extract and the lack of Okazaki piece synthesis characteristic of the dnaG extract were both apparent in analysis of the dnaB dnaG mutant extract reaction . A hypothetical scheme to explain these results and those of others is presented.

Mol Gen Genet, 1981, 182(1), 19 - 24
The requirement for both DNA polymerase and 5' to 3' exonuclease activities of DNA polymerase I during Tn5 transposition; Sasakawa C et al.; By assaying transposition of Tn5 from lambda b221 cI857 rex::Tn5 (Berg 1977) in polA-proficient and deficient cells, both the polymerase activity and 5' to 3' exonuclease activity of DNA polymerase I have been shown to be required for transposition . This requirement could not be observed in three other systems in which the transposon donor replicon had existed in the PolA-proficient and deficient cells before the transposition event to be assayed occurred . By analogy to Tn3, this may indicate that the repressor encoded by Tn5 has already been expressed and hence become rate-limiting in the overall transposition process, even PolA-deficient cells still possessing a residual activity . One PolA mutant was found among more than 50 transposition deficient (tnp) mutants isolated by the use of lambda b221 cI857 rex::Tn5.

Mol Gen Genet, 1981, 182(1), 112 - 8
The isolation and characterization of escherichia coli dnaB::Tn10 insertion mutations; Sclafani RA et al.; Exploitation of the ability of the ban protein encoded by phage P1 to compensate for dnaB-defective host mutations, allowed the isolation of dnaB::Tn10 insertion mutations . The presence of P1bac prophage was required for survival of dnaB::Tn10 mutants, and such lysogens were cryosensitive . The insertions were shown to map in dnaB by transduction and this was confirmed by complementation analysis . The dnaB::Tn10 (P1bac) strains were non-permissive for lambda growth but did support the growth of lambda-dnaB+ specialized transducing phage . No antigenically active dnaB product could be detected by immunologic assays using either of two methods . In addition, it was shown that the observe cryosensitivity of P1bac suppression was a direct result of reversible inactivation of the ban protein at low temperature.

Mol Gen Genet, 1981, 181(4), 548 - 51
Cloning, restriction endonuclease mapping and post-transcriptional regulation of rpsA, the structural gene for ribosomal protein S1; Christiansen L et al.; Transducing lambda phages have been isolated that carry segments of the Escherichia coli chromosome in the aspC region, 20.5 min on the E . coli map . One of these phages, lambda aspC2, carries rpsA, the structural gene for the ribosomal protein S1 . A three kilobase fragment from this phage, cloned into either the plasmid pACYC184 or the plasmid pBR322, was found to express S1 . In cells carrying the rpsA gene on the high copy number plasmid pBR322 the rate of rpsA mRNA synthesis was increased 40-fold, whereas the rate of protein S1 synthesis was doubled, in comparison with these rates in an rpsA haploid.

Mol Gen Genet, 1981, 181(4), 532 - 4
Introduction of active enzymes into intact Escherichia coli cells by means of liposomes . Phenotypic suppression of uvr A and pol A mutants; Bresler SE et al.; Genetically deficient cells were supplied with the missing enzymes, purified from an independent source . The introduction of exogenous enzymes into the cells was effected by two independent methods: plasmolysis and liposome transformation . The latter procedure yielded a homogenous cell population which had been rescued from the defect even if the molecular weight of the enzyme amounted to 70 KD (Kilodaltons).

Mol Gen Genet, 1981, 181(4), 497 - 504
Role of the recF gene of Escherichia coli K-12 in lambda recombination; Armengod ME; When Escherichia coli K12(lambda) lysogens are infected with heteroimmune lambda phage, which are unable to replicate, general recombination between phage and prophage depends on the bacterial recF gene . It has been shown that in E . coli K12 postconjugational recombination, the RecF pathway only works with full efficiency if exonuclease I is absent (Clark 1973) . However, results presented in this paper indicate that under conditions in which lambda replication is blocked, the recombination pathway dependent on the recF gene is fully active in producing viral recombinants even, if the phage is Red+, in the presence of exonuclease I . In contrast, removal of lambda exonuclease and beta protein requires elimination of exonuclease I for an efficient RecF pathway . It is concluded that the Red system cooperates with the RecF pathway and that this cooperation involves overcoming the inhibitor effects of exonuclease I . In the absence of lambda exonuclease, beta protein stimulates recF-dependent recombination but does not suffice to prevent the negative effect of exonuclease I . In the presence of beta protein, full efficiency of the RecF pathway can be obtained either via cooperation with lambda exonuclease I or, if the viral exonuclease is defective, via inactivation of exonuclease I . Since activity of lambda exonuclease appears necessary to overcome the inhibitory effects of exonuclease I, it is proposed here that lambda exonuclease diverts material from the RecF pathway in a shunt reaction which allows completion of recF-initiated recombinational intermediates via a mechanism insensitive to exonuclease I . When lambda replication is allowed, the Rec system produces viral recombinants mainly via a recF-independent mechanism . However, a major contribution to the RecF pathway to lambda recombination is observed after removal of the Red system and exonuclease.

Mol Gen Genet, 1981, 181(4), 470 - 5
Regulation of the synthesis of adenylate cyclase in Escherichia coli by the cAMP -- cAMP receptor protein complex; Majerfeld IH et al.; The synthesis of the adenylate cyclase {ATP pyrophosphatelyase-(cyclizing), E.C . 4.6.1.1.} of Escherichia coli, appears to be regulated negatively by the cAMP receptor protein, CRP . This conclusion is based on a comparison of adenylate cyclase activities measured in vitro with the rates of cAMP synthesis by intact bacteria . The activity of adenylate cyclase, depending on conditions of growth, is also regulated by CRP; this effect, however, is indirect insofar as it is mediated by a protein or proteins under CRP control.

Genetics, 1981 Jan, 97(1), 11 - 25
Cryptic operon for beta-glucoside metabolism in Escherichia coli K12: genetic evidence for a regulatory protein; Defez R et al.; Escherichia coli K12 does not metabolize beta-glucosides such as arbutin and salicin because of lack of expression of the bglBSRC operon, which contains structural genes for transport (bglC) and hydrolysis (bglB) of phospho-beta-glucosides . Mutants carrying lesions in the cis-acting regulatory site bglR metabolize beta-glucosides as a consequence of expression of this cryptic operon (Prasad and Schaefler 1974) . We isolated mutations promoting beta-glucoside metabolism that were unlinked to bglR; some of these mutations were shown to be amber . All of them were mapped at 27 min on the E . coli K12 linkage map and appeared to define a single gene, for which we propose the designation bglY . Utilization of beta-glucosides in bglY mutants appeared to be a consequence of expression of the bglBSRC operon, since bglB bglR and bglB bglY double mutants had the same phenotype . All bglY mutations analyzed were recessive to the wild-type bglY+ allele . Phospho-beta-glucosidase B and beta-glucoside transport activities are inducible in bglY mutants, as they are in bglR mutants . Metabolism of beta-glucosides in both bglR and bglY mutants required cyclic AMP . We propose that bglY encodes a protein acting as a repressor of the bglBSRC operon, active in both the presence and absence of beta-glucosides, whose recognition site would be within the bglR locus.

Genetika, 1981, 17(3), 420 - 3
{Induction of transposon Tn1 translocation in UV-irradiated Escherichia coli cells}; Smirnov SP et al.; Ampicillin transposon Tn1 translocates from plasmid RP4 into E . coli chromosome with a frequency of about 3.10(-4) per cell . Irradiation of bacteria with UV-light increases the frequency of translocation essentially . Mutation in lexA gene controlling the expression of cell UV-inducible functions blocks the induction of transposon translocation . Protein synthesis inhibitor--chloramphenicol and transcription inhibitor--rifampicin decrease the effect of UV-light on transposition process . A possible mechanism of inducible transposition is discussed.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 95 - 9
DNA sequences similar to those around the simian virus 40 origin of replication are present in the monkey genome; McCutchan TF et al.; We report the molecular cloning of African green monkey genomic DNA segments that include regions of homology to the origin of replication of simian virus 40 (SV40) . Three clearly different cloned segments 14 to 17 kilobase pairs (kb) long were isolated from a genomic library in lambda phage . We estimate that each of the three is repeated fewer than four times in the monkey genome . The SV40-like regions represent a small portion of the cloned segments, and these regions cross hybridize only weakly with one another . One of the three segments is described here in detail . Although the entire segment occurs only once or twice in the monkey genome, it contains DNA sequences (other than the SV40-like sequences) that are repeated elsewhere in the genome including in the other two cloned segments . The homology to SV40 is contained within about 300 base pairs of monkey DNA and is limited to the region around the viral replication origin . The nucleotide sequence of the SV40-like region was determined . It contains a large number of short stretches homologous to three specific noncoding domains around the SV40 origin of replication: the 27-base-pair region of dyad symmetry, the first set of (short) repeats that occur just on the late side of the origin, and, further in the late direction, the two 72-base-pair-long repeats . Although these components are grouped in the monkey DNA, as they are in SV40 DNA, their relative juxtaposition is scrambled.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 582 - 6
Herpes simplex virus thymidine kinase activity of thymidine kinase-deficient Escherichia coli K-12 mutant transformed by hybrid plasmids; Kit S et al.; A hybrid plasmid (pAGO) that contains the herpes simplex virus type 1 (HSV-1) thymidine kinase (TK) gene in the form of a 2-kilobase-pair (kbp) Pvu II fragment inserted at the Pvu II site of plasmid pBR322 was used to transform TK- Escherichia coli K-12 strain KY895 . pAGO-transformed KY895 cells exhibited partially restored ability to incorporate {3H}dThd into DNA and an HSv-1-specific TK activity . Bacteria cured of plasmid pAGO (or transformed by plasmid pBR322) did not show enhanced incorporation of {3H}dThd into DNA or HSV-1 TK activity . Plasmid pMH1A was derived from pAGO by deletion of 2067 bp of DNA sequence from pBR322 and 105 bp from the HSV-1 TK gene . E . coli K-12 strain KY895 cells transformed by pMH1A did not show enhanced incorporation of {3H}dThd into bacterial DNA, although pMH1A DNA isolated from transformed KY895 cells, like pAGO DNA, did transform TK- mouse fibroblast {LM(TK-)} cells to the TK+ phenotype . The expression of HSV-1 TK activity by E . coli K-12 suggests that intervening sequences may be absent from the coding region of HSV-1 tk or that the coding region of the gene possesses short intervening sequences which do not disrupt the translational reading frame.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 459 - 63
Excision of transposon Tn5 is dependent on the inverted repeats but not on the transposase function of Tn5; Egner C et al.; The excision of Tn5 from sites of insertion in the Escherichia coli genome was studied by examining the reversion of lac::Tn5 insertion mutations to lac+ . We find that: (i) the frequency of excision depends on the site of Tn5 insertion, (ii) excision occurs efficiently in recA- cells, (iii) excision does not require a Tn5-encoded transposition function, and (iv) efficient excision requires the inverted repeats of Tn5 . We propose that excision of Tn5 is similar to the formation of spontaneous deletions and occurs by slippage during DNA synthesis.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 133 - 7
Expression of simian virus 40-rat preproinsulin recombinants in monkey kidney cells: use of preproinsulin RNA processing signals; Gruss P et al.; The complete rat preproinsulin gene I was cloned into a simian virus 30 (SV 40) vector . Most of the late region of the viral vector, including the SV40 intervening sequences (introns) and all of the major splice junctions, was deleted and replaced by the entire rat insulin gene . The recombinant molecules and a temperature-sensitive helper virus (tsA28) were inoculated into monkey kidney cultures . The formation of stable transcripts of the insulin insert was as efficient as the production of late SV40 mRNA . Analysis of these transcripts indicated that the rat preproinsulin gene nucleotide signals involved in RNA splicing and poly(A) addition were used . Examination of the 5' ends of the mRNAs showed several classes, one of which was the same size as the authentic rat insulinoma mRNA . This suggests that a portion of the transcripts may be initiated or processed faithfully, or both, at their 5' ends within rat insulin sequences . Significant quantities of a protein identified as rat proinsulin were synthesized . Detection of most of the proinsulin in the tissue culture medium suggests that this protein was secreted.

Mol Gen Genet, 1981, 181(3), 384 - 9
Isolation and mapping of Escherichia coli K12 mutants defective in Tn9 transposition; Ilyina TS et al.; Five mutants (called tnm) of Escherichia coli with impaired ability for transposition of Tn9 were isolated after treatment with ethyl methanesulfonate (EMS) or N-methyl-N'-nitro-N-nitrosoguanidine (NG) . The map locations of the tnm mutations were determined by a combination of Hfr matings, F' episome complementation and P1 transductional mapping . The data obtained show that the five tnm mutations are located near 91 min on the Escherichia coli linkage map and are cotransducible with the metA marker with a frequency of 3%-4% . Introduction of F' plasmids containing this region complements the Tnm- phenotype for the two mutants tested i.e . tnm-1 and tnm-2 are recessive in tnm+/tnm- merodiploids.

Gene, 1981 Jan-Feb, 13(1), 25 - 35
Construction and characterization of new cloning vehicles . V . Mobilization and coding properties of pBR322 and several deletion derivatives including pBR327 and pBR328; Covarrubias L et al.; A DNA sequence essential for the R64drd11 + ColK-mediated conjugal transfer of pBR322 has been located in a 540 bp HaeIII fragment (HaeIII-2) between the vegetative origin of replication and the tetracycline resistance (Tcr) gene of this vector . The pBR322 derivatives pBR327 and pBR328 lack this DNA sequence and are not mobilized by conjugation . Two derivatives of pBR328 were constructed by re-inserting the HaeIII-2 fragment in both orientations into the chloramphenicol-resistance gene of the same vector . One orientation of the HaeIII-2 fragment permitted mobilization by conjugation while the opposite orientation prevented mobilization . Further examination of pBR322 and derivatives revealed that the region between the origin of replication and Tcr gene also plays a role in regulating plasmid copy number.

Gene, 1981 Jan-Feb, 13(1), 13 - 23
Cloning and characterization of the natural lactose operator; Sadler JR et al.; A 55-bp DNA segment carrying the wild-type lactose operator sequence has been cloned . Its sequence is: (Formula: see text) . With the exceptions of the bases at positions 19 and 41, 26 and 34, and 28 and 32, the sequence is a perfect inverted repeat about base pair 30 . This segment was obtained from the wild-type lactose promoter and operator region of lambda h80dlac phage DNA by a combination of in vitro and in vivo steps . Up to four direct-repeat copies of this segment have been cloned in plasmid pMB9 and pBR325 . Repressor affinity for this 55-bp fragment does not differ significantly from that for a 40-bp synthetic operator fragment cloned previously, even though the 55-bp fragment contains the complete set of sequence symmetries associated with the natural operator, whereas the 40-bp fragment does not . An improved procedure for operator purification is described: this was used to prepare 14 mg of the 55-bp fragment over a 2-month period.

Tohoku J Exp Med, 1981 Jan, 133(1), 53 - 60
Effect of conjugated estrogen on disseminated intravascular coagulation induced by endotoxin infusion in rabbits; Maki M; Since conjugated estrogen has activities of inhibiting capillary permeability and of blocking alpha-adrenergic action, this study was undertaken to evaluate the effect of conjugated estrogen on experimentally induced disseminated intravascular coagulation (DIC) by endotoxin infusion in rabbits . Endotoxin from E . coli alone was infused into 17 rabbits in a rate of 90 micrograms/kg/hr for 10 hr, the other 17 were given endotoxin with 20 mg of conjugated estrogen, and 6 were infused 20 mg of conjugated estrogen alone . The results obtained were as follows: (1) Decreases in platelet, fibrinogen and plasminogen, prolonged prothrombin time and partial thromboplastin time were noted in animals receiving intravenous drip infusion of endotoxin . All these laboratory findings were typical of consumption coagulopathy . Histologically, fibrin thrombi were demonstrated in the glomeruli, which also indicated the presence of DIC . (2) These changes were almost equally demonstrable in the rabbits given endotoxin alone and in those with endotoxin plus conjugated estrogen . (3) The group of rabbits receiving endotoxin and estrogen, however, showed a significantly low mortality during the study, compared with the group receiving endotoxin alone.

Poult Sci, 1981 Jan, 60(1), 34 - 7
Immune response to Newcastle disease virus vaccine, fowl-pox vaccine, and Escherichia coli vaccine in Bedouin and White Leghorn chickens; Heller D et al.; Immune response to Newcastle disease virus (NDV) vaccine, fowl pox, and E . coli vaccine was compared in the native Bedouin fowl of the Sinai desert, in a commercial Leghorn layer strain, and in the reciprocal crosses between them . Differences were not found in antibody titer levels to attenuated or inactivated NDV vaccines, in the proportion of birds showing post-vaccination immunity to fowl pox, or in the kinetics of postvaccination NDV titer levels . Rate of development of titer to Escherichia coli from day 1 to day 4, however, was significantly more rapid in Bedouin chicks than in the purebred Leghorn or the reciprocal crosses.

Genetika, 1981, 17(1), 45 - 51
{Instability of hybrid plasmids containing Drosophila melanogaster DNA in rec+ and rec- Escherichia coli K-12 strains}; Mel'nikov AL et al.; The stability of hybrid plasmids, constructed on the basis of vector pCV20(AprTcr) and containing HindIII fragments of Drosophila melanogaster DNA (pDm6, pDm9) and PstI fragments of D . melanogaster DNA (pDm39, pDm187, pDm189) was studied . After the transformation of E . coli HB101 recA and Escherichia coli 802 rec+ and selection to Tcr (pDm6, pDm9), or to Apr (pDm39, pDm189, pDm187) 0.04--9% of clones with reduced resistance to Tc or Ap was detected . The hybrid plasmids are more stable in rec-, but not in rec+ strain, the stability depends of the nature of cloned DNA, and on the site of vector DNA in which foreign genes are cloned . Restriction endonuclease analysis revealed that all plasmids of the clones with reduced Tcr or Apr lost the inserted DNA and the excision of foreign DNA occurred precisely in the sites of cloning . We suggest that the genome of the hybrid plasmid in the region of foreign insertion has a conformation which allows the bringing together the ends of cloned DNA with the following excision of the foreign genes.

Genetika, 1981, 17(1), 33 - 44
{Genetic study of Escherichia coli K-12 mutations that affect the transposition process}; Ilina TS et al.; Results of genetic analysis of bacterial tnm mutations influencing transposition of Tn9 are presented . Five independent tnm mutations were mapped at 90,5 min of the E . coli genetic map . The tnm mutations were 3,5 and 46,5% contransducible with metA and malB markers, respectively . Two tnm mutations tested were recessive in tnm+/tnm- merodiploids . The effect of tnm mutations on other transposons--Tn10, Tn601, Tn3 and Tn5 was examined . It was shown that tnm1 and tnm2 mutations reduced the frequency of transposition of Tn10, Tn3, Tn5 and Tn601 from the genome of phage lambda and inhibited intracellular development of the infecting Mu phage . The latter effect was probably due to the inhibition of Mu integration into bacterial chromosome . The tnm3 mutation affected the transposition of Tn9 only.

Mol Gen Genet, 1981, 181(1), 95 - 100
Molecular cloning of the fnr gene of Escherichia coli K12; Shaw DJ et al.; Mutations in the fnr gene of Escherichia coli have pleiotrophic effects leading to deficiencies in the reduction of fumarate and nitrate, hydrogen production and the ability to grow anaerobically with fumarate or nitrate as terminal electron acceptors . Transducing phages (lambda fnr) carrying the wild-type fnr gene were isolated from populations of artificially-constructed recombinant lambda phages by their ability to complement the lesions of fnr mutants . The lambda fnr phages restored anaerobic growth with fumarate and nitrate as electron acceptors and as prophages, they promoted normal synthesis of fumarate reductase, nitrate reductase and hydrogenase in fnr mutants . Five independently-isolated lambda fnr phages each contained a R.HindIII fragment (11.5 kilobases) that possessed three internal R.EcoRI targets and had inserted with the same orientation relative to the phage . A physical map of the fnr region was constructed by restriction analysis and flanking fragments were identified by DNA : DNA hybridization.

Mol Gen Genet, 1981, 181(1), 87 - 94
The tetracycline resistance transposons Tn1721 and Tn1771 have three 38-base-pair repeats and generate five-base-pair direct repeats; Schoffl F et al.; The 10.7 kilobase (kb) tetracycline resistance transposons Tn1721 and Tn1771, isolated from disparate sources, are completely homologous on the basis of heteroduplex analyses . Both transposable elements are capable of forming multiple duplications of a 5.3 kb portion encompassing the resistance genes (tet region) . A model accounting for both, recA-independent translocation and recA-dependent amplification, postulates two direct and one inverted repeat as essential constituents of the transposons . DNA sequence analyses of Tn1721 and Tn1771 have substantiated this model . They demonstrated three identical 38 base pair repeats identically in both transposons dividing them into a "minor transposon" and a tet region . Identical sequences of at least 87 base pairs providing recombination "hot spots" for gene duplication have been found at the ends of the repetitious tet region . Translocation of Tn1721 and Tn1771 generates five base pair direct repeats at the respective sites of insertion . On the basis of the heteroduplex molecules and sequences analyzed the two transposons are identical.

Mol Gen Genet, 1981, 181(1), 8 - 12
Nucleotide sequence of the region of the origin of replication of the broad host range plasmid RK2; Stalker DM et al.; A DNA sequence consisting of 617 base pairs (bp) from the region of the origin of replication of the broad-host range plasmid RK2 has been determined . Included within this sequence is a 393 bp HpaII restriction fragment that provides a functional origin or replication when other essential RK2 specified functions are provided in trans . Also contained in this sequence is a region, distinguished functionally from the replication origin, which is involved in the expression of inc2 incompatibility, i.e., the ability of derivatives of RK2 to eliminate a resident RK2 plasmid . The 617 bp sequence includes eight 17 base pair direct repeats with 5 located within the region required for a functional replication origin and 3 within the region involved in inc2 incompatibility . In addition, a 40 bp region rich in A-T followed by a 60 bp stretch having a high G + C content is present . Deletion evidence indicates that the A-T rich and possibly the G + C regions are required for a functional replication origin . Based on the evidence contained in this and the preceding paper (Thomas et al . 1980 b) a model will be presented for the involvement of these specific sequences in the initiation of RK2 DNA replication, plasmid maintenance and plasmid incompatibility.

Mol Gen Genet, 1981, 181(1), 52 - 6
An Escherichia coli mutant thermosensitive in the B subunit of DNA gyrase: effect on the structure and replication of the colicin E1 plasmid in vitro; Orr E et al.; An E . coli strain which carries a mutation conferring clorobiocin resistance and temperature sensitivity for growth has recently been described and evidence has been presented suggesting that the mutation is located in the gyrB gene (Orr et al . 1979) . The replication of the ColE1 plasmid was analysed in cell-free extracts from this thermosensitive strain . These extracts were totally deficient in the replication of exogenous plasmid DNA and were unable to maintain the superhelical structure of the plasmid DNA . Both defects could be fully complemented by addition of purified gyrB protein.

J Virol, 1981 Jan, 37(1), 295 - 306
Recurring defective variants of simian virus 40 containing monkey DNA segments; Papamatheakis J et al.; Four independently and newly isolated defective variants of simian virus 40 have been characterized . All four are very similar, if not identical, to two previously and independently isolated variants (Wakamiya et al., J . Biol . Chem . 254:3584-3591, 1979; J . Papamatheakis, E . Kuff, E . Winocour, and M . F . Singer, J . Biol . Chem . 255:8919-8927, 1980) . The documented similarities include restriction endonuclease maps and the presence of the same monkey DNA segments covalently linked to simian virus 40 DNA sequences . Each of the newly described variants was first detected upon serial passaging of wild-type simian virus 40 at a high multiplicity of infection at 33 degrees C as recently described (M . F . Singer and R . E . Thayer, J . Virol . 35:141-149, 1980) . A variety of experiments support the idea that the various isolates were independent and do not reflect inadvertent cross-contamination . Two of the new isolates arose during passage of wild-type strain 777 virus in BSC-1 cells, one during passage of strain 776 in BSC-1 cells, and one during passage of strain 776 in primary African green monkey kidney cells . The two variants obtained after passage of strain 776 were shown to contain a particular recognition site for restriction endonuclease MboII within their simian virus 40 DNA segments, as do the two previous isolates . This site is not present in wild-type strain 776 DNA but is shown here to be present in wild-type strain 777 DNA . The surprising recurrence of closely related variants and particularly the unexpected presence of the endo R.MboII site in variants derived from passaging strain 776 suggest that these variants may arise by mechanisms other than recombination between the initial infecting viral genome and the host DNA.

J Virol, 1981 Jan, 37(1), 244 - 7
Nucleotide sequence at polyoma VP1 mRNA splice sites; Srivatsan ES et al.; Double-stranded DNA complementary to total cytoplasmic polyadenylated RNA isolated late in infection from polyoma virus-infected mouse 3T6 cells was cloned in Escherichia coli by using the large HindIII-BamHI fragment of pBR322 plasmid DNA . Polyoma-specific DNA inserts were detected by hybridization, and then nucleotide sequences were determined from two clones . The sequence of the (formula see text) with prototypical mammalian splice sites, and the dashed arrows indicate possible alternative splice sites leading to the same spliced product . A sequence of 897 nucleotides was spliced out of the primary transcript during the processing of the mature VP1 mRNA . Restriction enzyme mapping with four other independently isolated clones indicates that these are the major splicing signals for the VP1 message . The distal splice site is 48 nucleotides upstream from the initiator codon.

J Virol, 1981 Jan, 37(1), 226 - 38
Regulatory and coding potential of the mouse mammary tumor virus long terminal redundancy; Donehower LA et al.; Molecular clones containing the 3' half of newly integrated mouse mammary tumor virus (MMTV) DNA with adjacent mouse cellular sequences were characterized . In addition, we cloned the long terminal redundancy joint from the unintegrated circular form of MMTV DNA . The entire nucleotide sequence of the integrated and part of the unintegrated terminal redundancy was determined; this allowed us to delineate the boundaries of the MMTV long terminal redundancy, which comprises 1,327 base pairs . The position of possible RNA polymerase II initiation and termination signals corresponded closely to the expected regions of viral RNA initiation and termination specified by current models . The MMTV long terminal redundancy also contained a large open reading frame with sufficient information for a protein of 198 amino acids . Initial comparison of flanking 3' cellular sequences from three independent integrated clones suggested there was no host sequence specificity in the MMTV integration event . However, specificity of integration with respect to viral sequences was precise.

J Virol, 1981 Jan, 37(1), 181 - 90
Isolation of recombinant DNA clones carrying complete integrated proviruses of Moloney murine leukemia virus; Bacheler L et al.; EcoRI DNA fragments from a Moloney murine leukemia virus (M-MuLV)-infected mouse fibroblast line (M-MuLV clone A9) were cloned in lambda phage Charon 4A cloning vector to derive clones containing integrated M-MuLV proviral DNA . A 10- to 16-megadalton class of EcoRI fragments was chosen for cloning, based on (i) its ability to induce XC-positive virus upon transfection of NIH/3T3 cells, and (ii) its content of a 0.8-megadalton viral KpnI fragment diagnostic for M-MuLV . Six recombinant DNA clones were isolated which contain a complete M-MuLV provirus, as judged by (i) restriction endonuclease mapping and (ii) the fact that all of the clones gave rise to XC-positive, NB-tropic virus upon DNA infection in NIH/3T3 cells . The sizes of the inserts were 12.0 (for three clones) or 12.5 megadaltons (for three clones) . Restriction mapping indicated that these six clones represent five different M-MuLV proviral integrations into different cellular DNA sites.

J Virol, 1981 Jan, 37(1), 171 - 80
Cloning of a DNA fragment from the left-hand terminus of the adenovirus type 2 genome and its use in site-directed mutagenesis; Stow ND; The HpaI E fragment (0-4.5 map units) of adenovirus type 2 (Ad2) DNA was cloned in the plasmid vector pBR322 . Excision of the viral insert with PstI and XbaI generated a fragment which comigrated with Ad2 XbaI-E (0-3.8 map units), and this fragment was ligated to the 3.8-100 fragment generated by XbaI cleavage of the DNA of the Ad5 mutant, dl309 (N . Jones and T . Shenk, Cell 17:683-689, 1979) . Transfection with the ligation products resulted in the production of progeny virus which was able to replicate on both HeLa and line 293 cells, demonstrating the biological activity of the sequences rescued from the plasmid . Small deletions were introduced around the SmaI site (map position 2.8) within the cloned viral insert, and the altered DNA sequences were reintroduced into progeny virus as described above . The mutant viruses grew well on line 293 cells but plaqued with greatly reduced efficiency on HeLa cells, exhibiting a host range phenotype similar to previously described mutants with lesions located within this region of the genome . When plasmid-derived left-end fragments containing pBR322 DNA sequences to the left of map position 0 were ligated to the 3.8-100 fragment of dl309 DNA, the infectivity of the ligation products was not reduced . However, all progeny viruses examined yielded normal-size restriction enzyme fragments from their left-hand ends, indicating that the bulk of the pBR322 DNA sequences are removed either prior to or as a consequence of the replication of the transfecting DNA molecules.

J Infect Dis, 1981 Jan, 143(1), 114 - 21
Mecillinam resistance in Escherichia coli: dissociation of growth inhibition and morphologic change; Barbour AG et al.; The resistance of mecillinam of Escherichia coli strain RF292, which was isolated from a patient during relapse of septicemia, was investigated . Although strain RF292 underwent morphologic change at the same concentration of mecillinam as the wild-type strain (RF81) and a revertant strain (RF293), RF292 was 128-fold more resistant than RF81 or RF293 to growth inhibition by mecillinam . The resistance of RF292 was associated with a 15%-35% longer generation time and a 30%-35% smaller cell volume than RF81 or RF293 . The latter two strains . When growing slowly under nutritionally deprived conditions, assumed a mecillinam-resistant phenotype . Thus, resistance of E . coli to growth inhibition by mecillinam can occur in association with a slow growth rate and a small cell volume of either hereditary or environmental origin.

Cell, 1981 Jan, 23(1), 215 - 27
Three Tn10-associated excision events: relationship to transposition and role of direct and inverted repeats; Foster TJ et al.; We describe three related DNA alterations associated with transposon Tn10: precise excision of Tn10, nearly precise excision of Tn10 and precise excision of the nearly precise excision remnant . DNA sequence analysis shows that each of these alterations results in excision of all or part of the Tn10 element, and each involves specific repeat sequences at or near the ends of the element . Furthermore, all three events are structurally analogous: in each case, excision occurs between two short direct-repeat sequences, with resulting deletion of all intervening material plus one copy of the direct repeat; and in all three cases, the direct repeats involved occur at either end of an inverted repeat . Analysis of mutant Tn10 elements and characterization of bacterial host mutations suggest that all three types of excision events occur by pathways that are fundamentally distinct from the pathway(s) for Tn10-promoted transposition and other DNA rearrangements (deletions and inversions) actively promoted by the element . In addition, precise excision and nearly precise excision appear to occur by very closely related or identical pathways; and several lines of evidence suggest that the 1400 bp inverted repeats at the ends of Tn10 may play a structural role in both of these events . The third excision event appears to occur by yet another pathway.

Cell, 1981 Jan, 23(1), 191 - 9
The functional differences in the inverted repeats of Tn5 are caused by a single base pair nonhomology; Rothstein SJ et al.; The inverted repeats of Tn5 are functionally different . One repeat codes for larger polypeptides, which are required for transposition . The other repeat has a better promoter for the neomycin resistance gene in the region of the repeat near the unique sequences . These dissimilarities are now shown to be caused by a single base pair difference . This change both creates a better promoter sequence and codes for part of a new UAA nonsense codon . Mutants in which the DNA sequence of a repeat is altered only at this base pair are shown to function like the opposite repeat . Furthermore, it is possible to suppress the UAA nonsense codon with an ochre suppressor, making the previously abbreviated polypeptides functional in transposition.

Mutat Res, 1981 Jan, 88(1), 1 - 15
Studies on the genotoxicity of some fluorescein dyes; Haveland-Smith RB et al.; The activities of 2,4,5,7-tetraiodofluorescein, disodium salt (erythrosine) and 2 phloxine dyes (2,4,5,7-tetrabromo-12,15-dichlorofluorescein, dipotassium salt and the disodium salt of 2,4,5,7-tetraiodo-12,15-dichlorofluorescein) have been determined using DNA-repair, fluctuation and treat-and-plate assays . Tests were conducted with and without illumination from a daylight fluorescent lamp . Both phloxine dyes were active in a rec assay but only in the absence of a rat-liver microsomal metabolising system . Erythrosine was inactive under all conditions . Although the results agreed with some of the published data for these foods and cosmetic colours, previous reports of photodynamic activation and mutagenicity were not confirmed . In the light of recent concern over the efficacy of bacterial DNA-repair tests, it is considered that the results obtained are not at present conclusive evidence for genotoxic hazard of any of the dyes studied.

Folia Microbiol (Praha), 1981, 26(1), 1 - 7
Catabolite repression during single and multiple induction in Escherichia coli; Jiresova M et al.; Intracellular concentration of cAMP regulates the synthesis of enzymes sensitive to catabolite repression . The relationship between the single and multiple induction of beta-galactosidase (EC 3.2.1.23), L-tryptophanase (EC 4.1.99.1), D-serine deaminase (EC 4.2.1.14), L-asparaginase (EC 3.5.1.1) and L-malate dehydrogenase (EC 1.1.1.37) was studied and the effect of cAMP level on the induction in Escherichia coli Crookes (ATCC 8739) was investigated . A varying degree of catabolite repression was observed during induction of individual enzymes induced separately on different energy sources . The synthesis of l-tryptophanase was most sensitive, whereas l-asparaginase was not influenced at all . Exogenous cAMP was found to overcome partially the catabolite repression of beta-galactosidase and D-serine deaminase, both during single induction . The synthesis of l-malate dehydrogenase was negatively influenced by the multiple induction even in the presence of cAMP; on the other hand, the synthesis of l-tryptophanase was stimulated, independently of the level of the exogenous cAMP . Similarly, the activity of L-asparaginase slightly but significantly increased during the multiple induction of all five enzymes; here too the activity increase did not depend on exogenous cAMP.

Eur J Biochem, 1981 Jan, 113(2), 369 - 74
The electrochemical proton gradient generated by the fumarate-reductase system in Escherichia coli and its bioenergetic implications; Hellingwerf KJ et al.; Proton translocation, coupled to electron transfer in the fumarate reductase system, generates and electrochemical potential gradient for protons (delta approximately mu H+) . The magnitude of this free energy gradient has been determined in the Escherichia coli strains ML 208-225 and AN 283 . The measurements were performed in (inverted) membrane particles, right-side out membrane vesicles and EDTA-treated intact cells in external media of various ionic compositions and pH . The maximal values of delta approximately mu H+ in these three systems were +103, -101 and -105 mV, respectively . This implicates that in E . coli, upon transition from oxygen to fumarate as electron acceptor, the magnitude of the delta approximately mu H+ decreases considerably . This change of delta approximately mu H+ has substantial consequences for the cellular metabolism.

J Bacteriol, 1981 Jan, 145(1), 521 - 32
Genetic analysis of the RecE pathway of genetic recombination in Escherichia coli K-12; Gillen JR et al.; The RecE pathway of genetic recombination in Escherichia coli K-12 was defined to be the pathway that is utilized in deoxyribonucleic acid exonuclease V (ExoV)-defective cells which express constitutively recE+, the structural gene for deoxyribonucleic acid exonuclease VIII . Dependence on ExoVIII was shown by the occurrence in a recB21 sbcA23 strain of recombination deficiency mutations in recE, the structural gene for ExoVIII . Point mutations in recE were found as well as deletion mutations in which the entire Rac prophage, carrying recE, was lost . In addition, strain construction and mutagenesis revealed the dependence of the RecE pathway on recA+ and on recF+ . Dependence on a fourth gene was shown by a mutation (rec-77) which does not map near the other genes . The problem of distinguishing the RecE pathway from that previously called RecF is discussed.

J Bacteriol, 1981 Jan, 145(1), 233 - 47
Determination of the functions of hemolytic plasmid pHly152 of Escherichia coli; Noegel A et al.; The alpha-hemolytic Escherichia coli strain PM152 harbors three transmissible plasmids, which have molecular weights of 65 X 10(6) (pA152), 41 X 10(6) pHly152), and 32 X 10(6) (pC152) . Plasmids pHly152 and pC152 belong to incompatibility groups J2 and N, respectively . By transforming E . coli K-12 with isolated plasmids, we showed that the genetic determinant required for hemolysis was located entirely on plasmid pHly152, and a physical map of this plasmid was constructed . By transposon mutagenesis, a deoxyribonucleic acid segment of about 3.5 X 10(6) daltons was identified as being essential for hemolysis . Most of the EcoRI and HindIII fragments of the hemolytic plasmid pHly152 were cloned by using pACYC184 and RSF2124 as vectors . Two classes of Tn3-induced hemolysis-negative mutants could be complemented by recombinant plasmids carrying fragments from the hemolysis region of pHly152, whereas a third class could be restored to hemolytic activity only by recombination between the mutant plasmids and a suitable recombinant deoxyribonucleic acid . These data suggest that there are at least three clustered cistrons which are required for hemolysis . Other EcoRI and HindIII fragments of pHly152 were identified as being essential for replication, incompatibility, transfer, and restriction.

J Mol Appl Genet, 1981, 1(1), 61 - 9
Two-step cloning of the Escherichia coli regulatory gene ompB, employing phage Mu; Wurtzel ET et al.; It is difficult to clone directly some regulatory or structural genes on the basis of their functions, because of their obscure properties or the leakiness of their mutants . To overcome this problem, a two-step cloning method with use of phage Mu was developed and applied to cloning of the ompB gene, an obscure regulatory gene for major outer membrane proteins of Escherichia coli . The ompB gene was first inactivated by phage Mu insertion, and the approximately 25-kilobase (kb) EcoRI fragment, which hybridized with phage Mu DNA, was cloned into a plasmid vector, pBR322 . This DNA fragment was considered to contain not only a portion of phage Mu DNA but also a portion of the ompB gene DNA . With this DNA as a probe, the wild-type ompB+ strain was found to contain a 12.7-kb EcoRI fragment which hybridized with the probe . In the second step, this 12.7-kb EcoRI fragment was cloned into a lambda phage vector, lambda 569 . Lysogenization of an ompB mutant with this phage suppressed OmpB- phenotypes, indicating that the 12.7-kb EcoRI fragment carried the ompB gene . The same 12.7-kb DNA fragment, as well as a 3.8-kb EcoRI-BamHI subfragment, was cloned into pBR322 . Both plasmid clones were able to suppress the OmpB- phenotypes upon transformation of an ompB mutant.

Tex Rep Biol Med, 1981-82, 41, 240 - 9
Interferons: chemical properties; Fantes KH; HuIFN-alpha has been found to consist of a family of 8-10 components . Their amino acid (165 and 166 residues) and nucleotide sequences are similar and also reveal some relationship to that of HuIFN-beta and even to those of murine alpha- and beta-interferons . It is thus likely that all mammalian interferons have originated from a common ancestral gene . Human beta- and some alpha-interferons have been obtained by genetic engineering in E.coli . All interferons seem to contain a relatively high proportion of hydrophobic amino acids and some of the components are glycosylated . The N-terminal residue of all HuIFN-alpha members is probably cysteine, that of the major HuIFN-beta peptide methionine and that of MuIFN-alpha and-beta probably alanine and isoleucine . Very little is known about the chemistry of any of the gamma-interferon species.

J Mol Appl Genet, 1981, 1(3), 165 - 75
Co-expression and amplification of dihydrofolate reductase cDNA and the Escherichia coli XGPRT gene in Chinese hamster ovary cells; Ringold G et al.; We have transformed Chinese hamster ovary cells with a plasmid containing mouse dihydrofolate reductase (DHFR) cDNA and the Escherichia coli xanthine-guanine phosphoribosyl transferase (XGPRT) gene under the control of the mouse mammary tumor virus and SV40 early promoters, respectively . Selection for the expression of XGPRT using the dominant selection scheme described by Mulligan and Berg yields clones that simultaneously express DHFR . Growth of these cells in progressively increasing concentrations of methotrexate, results in selection of cells that overproduce DHFR and its messenger RNA 250-500 fold . ANalyses of the plasmid DNA sequences in these cells reveal that the increased production of DHFR is due in part to gene amplification (approximately 50-fold) and in part to a selective overproduction of DHFR RNA . Last, the methotrexate-resistant cells contain 50 times more XGPRT RNA and DNA than the initial transformant; this demonstrates the potential for using gene amplification as a means for overproducing the products of genes linked to DHFR cDNA in plasmid vectors.

J Interferon Res, 1981, 1(4), 505 - 12
Effect of gamma interferon preparations on in vitro phagocytosis and degradation of Escherichia coli by mouse peritoneal macrophages; Degre M et al.; Treatment of mouse peritoneal macrophages by gamma (type II, immune) interferon depressed the ingestion of non-opsonized Escherichia coli mediated by the non specific receptor, and also the intracellular degradation of the ingested bacteria . These effects were time and dose-dependent, and sensitive for trypsin and pH 2 treatment . The intracellular concentration of three lysozomal enzymes, beta-glucuronidase, acid phosphatase and cathepsin D, was elevated in gamma interferon-treated macrophages.

Acta Microbiol Pol, 1981, 30(4), 307 - 18
Replication and expression of fragments of phage PM2 cloned in Escherichia coli K-12; Grzesiuk E et al.; DNA from PM2 phage was cloned, as HindIII fragments and inserted into the pBR322 vector in E . coli cells . It was shown, that replication of recombined plasmids starts from the pBR322 origin . Transcription of recombinant plasmids in E . coli cells, as well as translation in minicells was demonstrated and attributed to pBR322 and/or PM2 DNA sequences.

Dev Biol Stand, 1981, 50, 301 - 9
Restriction map of poliovirus type 2 cDNA; Kopecka H et al.; Poliovirus type 1 RNA was reverse-transcribed into c-DNA and inserted at the Pst I site of the plasmid vector pBR322 of E . coli . Resulting recombinant plasmids were analyzed by hybridization with RNase T1-resistant 32P-labeled oligonucleotides, and by restriction enzyme mapping . All of the genome was cloned in a series overlapping cDNA inserts, the longest of which was 3.2 kb . The restriction map of the poliovirus cDNA is presented.

Toxicology, 1981, 22(1), 9 - 21
Selective effects of metal ions on RNA synthesis rates; Niyogi SK et al.; The effects of 14 metal ions (chlorides) on the transcription of calf thymus DNA and phage T4 DNA with Escherichia coli RNA polymerase were tested . These assays were conducted under improved conditions of lower pH and in the absence of 2-mercaptoethanol to permit greater stability of the metal ions in solution . Among the divalent metal ions tested, the concentration-dependent order of inhibition of overall transcription is Pb2+ greater than Zn2+ greater than Cu2+ greater than Be2+ greater than Cd2+ greater than Ni2+ greater than Ca2+ greater than Co2+ greater than Mn2+ greater than Mg2+ greater than Sr2+ and is the same with either template . At pH 7.4 and in the absence of 2-mercaptoethanol, considerably lower concentrations of several of the divalent metal ions are needed for inhibition of overall transcription than at pH 8.1 and in the presence of 2-mercaptoethanol . Ca2+, Mg2+, Sr2+, Zn2+, Li+, Na+, and K+--considered to be non-mutagenic and non-carcinogenic--decrease chain initiation (measured with T4 DNA) at concentrations that inhibit overall transcription . Pb2+, Cd2+, Co2+, Be2+, and Mn2+--all mutagenic or carcinogenic--stimulate chain initiation (although at widely different rates) at concentrations that inhibit overall transcription . Cu2+ and Ni2+--both carcinogenic--stimulate initiation only at very low concentrations, followed by a progressive decrease in initiation at concentrations that inhibit overall transcription.

Microbiol Immunol, 1981, 25(12), 1243 - 54
Cloning of a 1.1-kb fragment including srnB+ gene in the F plasmid and isolation of an srnB mutant; Ohnishi Y et al.; The srnB+ gene, promoting stable RNA degradation at 42 C in the presence of rifampin, was cloned by using pBR322 as a vector; it was located on a 1.1-kilobase (kb) Eco RI/Bam HI fragment between 1.4 and 2.5 kb of the F plasmid . The region between 93.3 and 4.0 kb of the F plasmid was physically mapped by using restriction endonucleases EcoRI, HindIII, BamHI, PstI, and SmaI, with reference to a standard HindIII site in IS3 . An srnB1 mutant was isolated from a chimeric plasmid, pOY54, after treatment of its DNA with hydroxylamine . The srnB1 allele on the F fragment of the mutant plasmid was recessive to the wildtype allele . Thermal elevation of cell cultures to 39 C was high enough to promote RNA degradation in strain YS12 carrying plasmid pOY54.

Vet Med Nauki, 1981, 18(1), 27 - 31
{Isolation of an agglutinating anti-E . coli K 88+ serum}; Petkov M et al.; An agglutinating anti-K 88+ serum was obtained through immunizing rabbits with geometrically rising amounts of cell-free K 88 antigenic extraction . Use was made of bacterial suspensions cultured in Minka agar and homogenized at 8000 r . p . m . to remove the K 88 pili . The cell depot was removed by centrifugation at 15 000 r . p . m., and the protein in the supernatant was determined by the method of Kingsey . The titer of the K88 serum was within the 1:320-1:640 range . The specificity and activity of the serum was evaluated by the hemagglutination test, immunoelectrophoresis, and immunodiffusion . The serum is highly specific and yields positive agglutination results with all K 88+ Escherichia coli strains . It does not react with antigen - K 88-negative E . coli organisms as well as with the O antigen of the investigated strains.

Nucleic Acids Symp Ser, 1981, (9), 83 - 6
Synthesis and biological activity of 2'-deoxy-6-methyl-5-azacytidine and its alpha-D-anomer; Piskala A et al.; The stannic chloride catalyzed glycosylation of bis-tri-methylsilyl-6-methyl-5-azacytosine 2 with the halogenose 3 leading to the protected anomeric nucleosides 4a and 4b was investigated . Methanolysis of 4a and 4b afforded the corresponding free nucleosides 1a and 1b . Compounds 4a and 4b were also prepared by the isocyanate method via acetylamidinourea derivatives 6 . Antileukemic activity in vitro and inhibition of growth of E . coli by the title compounds are reported.

C R Seances Soc Biol Fil, 1981, 175(4), 426 - 45
{Regulation of the expression of Escherichia coli genes coding for the proteins involved in translation}; Grunberg-Manago M; We have described our present knowledge of the regulation of the expression of genes whose products are concerned with the protein biosynthesis in E . coli . In particular, we have discussed the mechanism of translational initiation which seems to be a crucial control point . Our own work on the organisation and regulation of the expression of a group of E . coli genes coding for initiation factor IF3 and two aminoacyl-tRNA synthetases was described in detail . This work illustrates the power of the new genetic engineering technology in studies on regulation at the molecular level.

Arch Virol, 1981, 68(3-4), 291 - 5
Studies on the mode of action of single-stranded polynucleotides which are antiviral against encephalomyocarditis virus infection of mice; Stebbing N; Poly(dI) and poly(dC) administered separately or sequentially show no antiviral effects against EMC virus infection of mice, whereas poly(rI) and poly(rC) are antiviral in such treatment regimens without evidence of interferon induction . The antiviral effects of poly(rI) and poly(rC) appear to depend on single-strandedness because their antiviral effects are decreased by annealing to poly(dC) and poly(dI) respectively . This decrease in antiviral effect would not seem to be due to an adverse effect of polydeoxyribonucleotides on EMC virus infection because the polydeoxyribonucleotides have no effect on the antiviral activity of another single-stranded RNA, E . coli tRNA.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 616 - 20
Isolation and partial nucleotide sequence of a cDNA clone for human histocompatibility antigen HLA-B by use of an oligodeoxynucleotide primer; Sood AK et al.; We have isolated a cDNA clone for one of the HLA-B locus alloantigens by hybridization with a 30-nucleotide-long DNA probe . The probe was isolated from a reverse transcriptase (RNA-dependent DNA nucleotidyltransferase)-catalyzed cDNA synthesis reaction on poly(A)-mRNA in which an oligonucleotide (5'-32P)dC-T-T-C-T-C-C-A-C-A-TOH served as a primer and in which dideoxynucleoside triphosphates were used to reduce the size and heterogeneity of the cDNA products . The desired cDNA clone was isolated from a library of recombinant cDNA clones in the plasmid pBR322 . The partial nucleotide sequence of the cDNA clone corresponds to the amino acid sequence of HLA-B7 antigen . The approach described in this paper is extremely sensitive and may be useful in cloning other genes for which the corresponding mRNA is present at low levels . This cDNA clone is nearly full length and can be used to isolate and to study the genes within the HLA region and to obtain expression of HLA-B peptides in cells.

Proc Natl Acad Sci U S A, 1981 Jan, 78(1), 224 - 8
Chromosomes in living Escherichia coli cells are segregated into domains of supercoiling; Sinden RR et al.; Torsional tension in the DNA double helix can be detected in living cells of Escherichia coli from measurements of the rate of trimethylpsoralen photobinding to the intracellular DNA . Here we show that this tension is relaxed in vivo when single-strand DNA breaks are introduced by gamma-irradiation and that approximately 160 nicks per genome equivalent of DNA are required to relax greater than 95% of the tension . Chromosomes containing less than 160 nicks per genome equivalent lose only a part of the tension, depending on the number of nicks . The remaining tension is maintained during incubations of cells at 0 degrees C . Chromosomes with tension relaxed by incubation of cells with inhibitors of DNA gyrase interact with the trimethylpsoralen probe independently of the number of nicks introduced by gamma-irradiation . The results fit a model in which the chromosome in growing E . coli cells (mean generation time, 30 min) is segregated into 43 +/- 10 domains of supercoiling per genome equivalent of DNA or 120 +/- 30 domains per nucleoid . The number of domains is unchanged in cells depleted of nascent RNA by growth with rifampicin, but varies somewhat in cells growing at different rates in different media.

Mol Gen Genet, 1981, 181(3), 367 - 72
A mutant rho ATPase from Escherichia coli that is temperature-sensitive in the presence of RNA; Kent RB et al.; The Escherichia coli mutant rho-115 suppresses lac operon polarity conferred by the lacZ::IS1 insertion MS319 . The ATPase activity of purified rho-115 protein was maximal at 40 degrees C, in contrast to 45 degrees C for rho+ . At higher temperatures (50 degrees C, 55 degrees C), the fractions of activities at maximal temperature were consistently lower for rho-115 compared to rho+ . The 30-minute time course of rho-115 ATP hydrolysis was linear at 37 degrees C but at 45 degrees C the linear kinetics of hydrolysis reached a plateau between 10 and 15 minutes . The 30-minute time courses for rho+ were linear at both 37 degrees C and 45 degrees C . The rho-115 and rho+ ATPase activities were equally heat-stable during preincubation at 45 degrees C in buffer . Inclusion of ATP during preincubation protected these rho proteins from inactivation to the same extent . The presence of polyC during preincubation protected rho+ activity but produced substantial inactivation of rho-115 ATPase . The presence of polyU during preincubation gave similar results . Concentrations of polyC between 625 ng/ml and 100 micrograms/ml yielded the same extent of rho-115 ATPase inactivation during preincubation at 45 degrees C . Thermal inactivation of rho-115 ATPase by polyC was halted by shifting preincubation temperature from 45 degrees C to 35 degrees C, indicating that polyC-induced destabilization of rho-115 was irreversible.

Ric Clin Lab, 1981 Jan-Mar, 11(1), 27 - 32
Which will be the most useful interferon?
Bocci V.
Promising signs of clinical success using interferon in cancer patients have spurred the interferon boom and pharmaceutical companies, lured by a potential lucrative market, are expanding their investment in the production of this natural drug . This paper points out that the interferons known so far have different pharmacokinetic and therefore it would be important, for the future clinical trials, to correlate pharmacokinetic behaviours with therapeutic efficacy . The empirical approach in use today may lead to some failure but, on the other hand, it may help in deciding more rapidly which interferon, or combination of interferons, is more effective . Furthermore, the importance of continuing the search for an ideal interferon inducer is stressed, owing to the growing awareness that interferon is a powerful antiviral and antiproliferative agent but, probably, needs other modulators to exert its full therapeutic potential.

Mol Gen Genet, 1981, 181(1), 69 - 73
Control of ribosomal RNA synthesis in Escherichia coli . V . Stimulation of rrnC gene transcription in vitro by a protein factor; Muto A; Ribosomal RNA synthesis has been investigated in an in vitro system consisting of purified E . coli RNA polymerase and phi 80d3 DNA carrying rrnC operon . rRNA comprises about 25% of the total RNA synthesized in this system under optimal conditions and is stimulated by a crude protein fraction prepared from E . coli cell extracts . The stimulation activity has been fractionated by a Sephacryl S200 column and detected as a single peak of about 50,000 daltons molecular weight . The activity specifically increases the initiation frequency of transcription of the rRNA operon on the phage DNA . The addition of ppGpp partially inhibits the stimulation activity for rRNA synthesis.

Eur J Biochem, 1981 Jan, 113(3), 587 - 93
Relationship between methylation of adenine near the 3' end of 16-S ribosomal RNA and the activity of 30-S ribosomal subunits; Igarashi K et al.; The relationship between methylation of adenine near the 3' end of 16-S ribosomal RNA and the activity of 30-S ribosomal subunits has been studied using 30-S subunits from kasugamycin-sensitive and kasugamycin-resistant bacteria . Analysis of the proteins of 30-S subunits by gel electrophoresis showed that the content of protein S1 in 30-S subunits from a kasugamycin-resistant strain was smaller than that in 30-S subunits from the parent strain . Although polyphenylalanine-synthetic activity of 30-S subunits from a kasugamycin-resistant strain previously methylated by a methylase purified from Escherichia Q13 was nearly equal to that of untreated 30-S subunits, both phenylalanine-synthetic activity and the content of protein S1 in the 30-S particles reconstituted from 23-S core particles and split proteins from the kasugamycin-resistant strain increased by prior methylation of 23-S core particles by the methylase . These results suggest that methylation of adenine near the 3' end of 16-S rRNA induces an increase of polypeptide-synthetic activity by the acceleration of binding of protein S1 to S1-depleted 30-S subunits.

Can J Microbiol, 1981 Jan, 27(1), 44 - 51
Hyperbaric oxygen toxicity and ribosome destruction in Escherichia coli K12; Harley JB et al.; The viability of resting suspensions of Escherichia coli K12 Ymel exposed to air plus 300 psi (1 psi = 6.895 kPa) oxygen (hyperbaric oxygen) decreased as an apparent first-order process after an initial period of constant viability . Control suspensions exposed to air plus 300 psi nitrogen (hyperbaric nitrogen) did not lose viability over the 96 h of the experiment . It was observed that a decrease in the refractive index of the cells preceded the loss of viability in hyperbaric oxygen . This finding together with electron micrographs, which showed extensive loss of ribosomal particles in bacteria incubated in hyperbaric oxygen, led us to suspect that ribosome injury or disassociation might be important in hyperbaric oxygen toxicity . In support of this we found that cellular RNA, labeled with {5-3H}uridine, was much more rapidly and more completely degraded in hyperbaric oxygen than in hyperbaric nitrogen . Furthermore, a far greater proportion of RNA was degraded than was DNA or protein . A direct assay for ribosome particles by sucrose gradient centrifugation showed that only 34% of the 70S ribosome particles was lost during the first 24 h in hyperbaric nitrogen whereas in hyperbaric oxygen 99.6% of the 70S particles was degraded during the same period . In hyperbaric oxygen the rate of viability loss between 24 and 72 h was equal to the rate of 70S ribosome degradation during the first 24 h . If 70S ribosome disassociation in hyperbaric oxygen continues at the same rate after first 24 h, then cumulative 70S ribosome disassociation or injury may lead to and provide an explanation for irreversible bacterial cell injury and the loss of viability.

Biochimie, 1981 Jan, 63(1), 53 - 60
RNA-protein complexes identified by crosslinking of polysomes; Skold SE; The bifunctional cleavable reagent diepoxybutane was used to investigate the crosslinking of proteins to the 16S and 23S RNA in Escherichia coli ribosomes . The crosslinking patterns from polysomes, accumulated in the absence and presence of oxytetracycline, as well as reassociated 70S ribosomes were compared . The 30S proteins: S3, S4, S5, S7, S8, S9, S12, S13, S14 and S18 were recovered crosslinked to the 16S RNA and the 50S: proteins L1, L2, L4, L13, L14-L21, L15, L16, L17, L18-L23, L19-22-24, L27 and L28 were recovered crosslinked to the 23S RNA, in all three associated states . Proteins crosslinked to the RNA of the heterologous subunit and therefore considered to be at or near the ribosomal subunit interface were, for all three states, proteins S1, S4, S6, S9, S12, S13, S14 and S18 from the small subunit and proteins L16, L17, L20 and L27 from the large subunit . Finally, the recovery of intrasubunit crosslinks was measured for the isolated subunits . Additional crosslinked complexes were observed between 16S RNA and S1, S2 as well as S6 from the 30S subunit; and between 23S RNA and L10, L11, L7/12 from the 50S subunit.

Mol Gen Genet, 1981, 184(2), 260 - 4
The effect of tra mutations on the synthesis of the F-pilin membrane polypeptide; Moore D et al.; We had previously demonstrated that several F specific polypeptide bands could be detected in the membranes of Flac, but not F- strains of Escherichia coli K12, (Moore et al . 1981) . One of these polypeptides co-migrated with F-pilin protein on polyacrylamide gels . We have now analyzed 35{S}methionine labelled membrane preparations from a series of strains containing Flac tra mutant plasmids . The F-pilin polypeptide was absent from preparations of strains containing all traA mutants tested, confirming the importance of the traA gene on F-pilin biosynthesis . A polypeptide which migrate in the F-pilin position was still present, however, in membranes prepared from Flac strains carrying mutations in traL, traE, traK, traB, traV, traW, traC, traU, traF, traH or traG despite the inability of these mutants to elaborate F-pili filaments . Thus, all of these gene products may be concerned with F-pilus assembly and outgrowth rather than biosynthesis of the F-pilin subunit . The polar mutation tra-4 did, however, prevent the appearance of pilin polypeptide, indicating that at least one unidentified gene in the region between traE and traG must also be required in F-pilin biosynthesis . Our analysis also permitted the identification of a 100,000 dalton membrane protein as the product of traG . The appearance of an F specific 12,000 dalton protein was prevented by traD amber mutants . As expected, traJ mutants prevented the expression of all the tra operon products detected except the product of traT . The traT product band was reduced only to 50 - 60% of its normal intensity.

Z Allg Mikrobiol, 1981, 21(5), 361 - 72
Regulation of ammonia assimilation in ammonia-limited chemostat cultures of Escherichia coli ML 30: evidence of bistability; Muller PJ et al.; In a preceding paper evidence of two stationary stable states (bistability) in the specific activity of glutamine synthetase (GS) in ammonia-limited steady-state cultures of Escherichia coli ML 30 at dilution rates (D) about 0.15 h-1 was described (Muller et al . 1977) . For better understanding of the regulation mechanisms leading to GS bistability chemostat experiments were performed over a wide range of dilution rates up to D = 0.8 h-1 . For each steady state the specific activities of GS and glutamate dehydrogenase (GDH)--the other key enzyme of the two NH3 assimilation routes in E . coli--and in addition the remaining NH3 concentration in the culture liquid were determined . Parallel to GS bistability two states of GDH activity and NH3 concentration are found . The higher state of GS is connected with a lower GDH activity and NH3 concentration . With rising D the GS activities decrease whereas GDH activities and NH3 concentrations increase . Since no adenylation of the GS is detectable GS bistability seems to be regulated on the level of enzyme synthesis like GDH bistability . From the experimental findings a mathematical model is derived based on the bottle neck enzyme theory of growth . It describes the dependence between the specific growth rates on the one hand and the specific enzyme activities and NH3 concentration on the other . It is shown that the specific uptake rate of the limiting NH3 and the specific growth rates, respectively, depend on the simultaneous action of two bottle neck enzymes which are connected by a regulative link.

Acta Microbiol Acad Sci Hung, 1981, 28(2), 205 - 10
Effect of chlorpromazine on conjugal plasmid transfer and sex pili; Mandi Y et al.; The major tranquillizer chlorpromazine (Cpz) inhibited the conjugal transfer of R and F'lac plasmids . The frequency of transfer of R-144 and R-100 plasmids was reduced with 2-3 log by Cpz at a concentration of 50-100 microgram/ml, while the frequency of RM-98 plasmid did not change under the same conditions . Cpz at 100 microgram/ml was an effective inhibitor of the transfer of F'lac plasmid . By means of electron microscopy and plaque assay, 100 microgram/ml Cpz was shown to reduce the adsorption rate of male specific ribonucleic acid phages MS-2 to the sides of F-pili . Common pili and flagellae seemed to be intact, but sex pili probably retracted in the presence of Cpz.

Infect Immun, 1981 Jan, 31(1), 17 - 20
Local immune response to Escherichia coli pili in experimental pyelonephritis; Smith JW et al.; The local immune response to pili of Escherichia coli O6:K13:H1 was determined in experimental hematogenous pyelonephritis in rabbits . Pili purified from sheared cells by ammonium sulfate precipitation were found to be pure by electron microscopy and negative for lipopolysaccharide by limulus lysate assay . Antipilus antibody was detected in serum and newly synthesized protein from infected animals with enzyme-linked immunosorbent assay . Serum and local (intrarenal) antibodies were of the immunoglobulin G class, were detectable by day 20 of infection, and persisted though 250 days of infection . These data suggest that pili are present on the organism at the site of infection, since they induce the local synthesis of antipilus antibody in experimental pyelonephritis.

J Bacteriol, 1981 Jan, 145(1), 620 - 3
Divergent effects of cyclic adenosine 3',5'-monophosphate on formation of type 1 fimbriae in different K-12 strains of Escherichia coli; Eisenstein BI et al.; Exogenous cyclic adenosine 3',5'-monophosphate either increased or decreased the expression of type 1 fimbriae in different cya strains of Escherichia coli, demonstrating the complexity of regulation of this surface protein.

Mol Biol Rep, 1980 Dec 31, 6(4), 209 - 12
Modification of 50S ribosomal subunits with N-bromosuccinimide; Lopez-Rivas A et al.; The 50S subunits of Escherichia coli ribosomes were modified with the tryptophan reagent N-bromosuccinimide, and the sulfhydryl groups, the modification of which is accompanied by stimulation of polypeptide synthesis (Lopez-Rivas, A . et al . (1978) Eur . J . Biochem . 92, 121), were regenerated by incubation with simple thiols . This treatment inactivates poly(U)-dependent polyphenylalanine synthesis, peptidyl transferase and elongation factor G-dependent GTPase . Incubation with proteins from untreated 70S ribosomes produces partial reactivation of polyphenylalanine synthesis and GTPase activity . Modification is accompanied by loss of 4-5 tryptophan residues per subunit.

J Biol Chem, 1980 Dec 25, 255(24), 11896 - 900
Nucleotide sequence of wheat chloroplastid 4.5 S ribonucleic acid . Sequence homologies in 4.5 S RNA species; Wildeman AG et al.; The nucleotide sequence of wheat (Triticum aestivum L.) chloroplastid ribosome-associated 4.5 S RNA is U-A-A-G-G-U-G-A-G-C-G-G-C-G-A-G-A-C-G-A-G-C-C-G-U-U-U-A-A-A-U-A-G-G-U-G-U-C-A-A -G-U-G-G-A-A-G-U-G-C-A-G-U-G-A-U-G-U-A-U-G-C-A-G-C-U-G-A-G-G-C-A-U-C-C-U-A-A-C- G-A-A-C-G-A-A-C-G-A-U-U-U-G-A-A-COH . The sequence is highly conserved among chloroplastid 4.5 S RNAs but not related to either the 5 S or 5.8 S rRNA species . When compared with 4.5 S RNAs from other origins, the results indicate that this molecule bears little sequence homology to the mammalian nuclear 4.5 S RNA but suggest that chloroplastid 4.5 S RNA may be related to the bacerial 4.5 S species . An estimate for the secondary structure of the wheat 4.5 S molecule was deduced from products of limited pancreatic and T1 ribonuclease digestion, and similarities with the Escherichia coli 4.5 S RNA are discussed.

J Biol Chem, 1980 Dec 25, 255(24), 11949 - 56
Structural, enzymatic, and genetic studies of beta-ketoacyl-acyl carrier protein synthases I and II of Escherichia coli; Garwin JL et al.; Beta-Ketoacyl-acyl carrier protein synthases I and II of Escherichia coli were purified and characterized . Synthase I was shown to have a molecular weight of 80,000 +/- 5,000 and to be composed of two similarly sized subunits . Synthase II had a molecular weight of 85,000 +/- 5,000 and also was apparently homodimeric . Gel electrophoresis of partial proteolytic digests demonstrated that synthases I and II share few if any common peptides . Synthases I and II also were shown to be unrelated by immunological criteria . An improved assay for beta-ketoacyl-acyl carrier protein synthase activity gave kinetic parameters for synthases I and II at both 27 degrees C and 37 degrees C using five long chain acyl-acyl carrier protein substrates . The properties of synthase II are consistent with the proposed role of this enzyme in the modulation of fatty acid synthesis by temperature . fabF mutants of E . coli lack synthase II . The fabF locus was mapped at min 24.5 of the E . coli genetic map and the clockwise map order was found to be pyrC, fabD, fabF, purB.

J Biol Chem, 1980 Dec 25, 255(24), 11857 - 60
ATP causes a large change in the conformation of the isolated alpha subunit of Escherichia coli F1 ATPase; Dunn SD; The physiochemical properties of the isolated alpha subunit of the Escherichia coli coupling factor ATPase, and changes resulting from the interaction of alpha with ATP, were studied . Amino acid analysis of alpha revealed 42% polar residues, 4 cysteine residues, and a single tryptophan residue . The partial specific volume, v, of alpha was 0.74 cm3 g-1 . Molecular weight value of alpha, determined by sedimentation equilibrium, of 55,000 to 59,000 were observed in guanidine hydrochloride, or in nondenaturing buffer in either the presence of absence of ATP, which alpha binds with high affinity . Sedimentation velocity experiments gave a value of s20,w0-3.52 S for alpha . In the presence of ATP, this value increased to 4.00 S, indicating a large conformational change of alpha when ATP is bound . A slow dissociation rate of alpha x ATP was suggested by the finding that a substantial portion of {2-3H}ATP mixed with alpha remained bound to the protein during native polyacrylamide gel electrophoresis, causing alpha to migrate with a higher relative mobility . A dissociation rate constant, koff, of 0.21 min-1 at 22 degrees C was measured by following the rate at which unlabeled ATP displaced {2-3H}ATP from the protein . The properties of the interaction of alpha with ATP suggest that this subunit may be the site of the "tightly bound" nucleotides of the coupling factor ATPase.

J Biol Chem, 1980 Dec 25, 255(24), 12073 - 80
Isolation and characterization of the yeast 3-phosphoglycerokinase gene (PGK) by an immunological screening technique; Hitzeman RA et al.; An immunological screening technique has been used for the detection of a specific antigen-producing clone in a bank of bacterial colonies containing hybrid plasmids . This technique involves covalent attachment of antiserum to cyanogen bromide-activated paper discs, contact of this paper with lysed colonies on agar plates, and finally detection of the bound antigen with 125I-labeled antibody . Using this method, we have identified an Escherichia coli colony, containing a yeast DNA insert in plasmid ColE1, that produces antigen which combines with antibody directed against purified yeast 3-phosphoglycerate kinase . The hybrid plasmid (pYe57E2) obtained by this procedure has been shown by both biochemical and genetic methods to contain the structural gene PGK for yeast 3-phosphoglycerate kinase . The location of the PGK structural gene on pYe56E2 was determined by immunological screening of E . coli colonies bearing plasmids containing various reconstructions of the original yeast DNA insert . Examination of the expression of the cloned yeast PGK gene in both E . coli and yeast has shown that functional enzyme is synthesized from the cloned gene in yeast, but not in E . coli.

J Biol Chem, 1980 Dec 25, 255(24), 12037 - 41
Subunits of the H+-ATPase of Escherichia coli . Overproduction of an eight-subunit F1F0-ATPase following induction of a lambda-transducing phage carrying the unc operon; Foster DL et al.; The proton-translocating ATPase complex (F1F0) of Escherichia coli was purified after inductin of a lambda-transducing phage (lambda asn5) carrying the ATPase genes of th unc operon . ATPase activity of membranes prepared from the induced lambda-unc lysogen was 6-fold greater than the activity of membranes prepared from strains lacking the unc-transducing phage, confirming the report of Kanazawa et al . (1979) Proc . Natl . Acad . Sci . U . S . A . 76, 1126-1130) . The F1F0-ATPase complex was purified in comparable yield from either enriched membranes or control membranes using a modification of the procedure reported by Foster and Fillingame ((1979) J . Biol . Chem . 254, 8230-8236) . EAch of the eight subunits that had been reported as components of the F1F0 complex from wild type E . coli was overproduced in the lambda-unc lysogen . All eight subunits co-purified in the same stoichiometric proportion as in the complex purified from wild type E . coli . We conclude that all eight subunits are likely coded by the small segment of chromosomal DNA carried by the lambda-transducing phage . These experiments provide the first evidence that all eight polypeptides are authentic subunits of the ATPase complex rather than contaminants that fortuitously co-purify.

Biochemistry, 1980 Dec 23, 19(26), 6096 - 104
Production of biologically active N alpha-desacetylthymosin alpha 1 in Escherichia coli through expression of a chemically synthesized gene; Wetzel R et al.; Thymosin alpha 1, an immune restorative polypeptide hormone, was synthesized in Escherichia coli by using recombinant DNA cloning techniques . Based on the known amino acid sequence, a gene coding for the thymosin alpha 1 polypeptide chain was designed and enzymatically assembled from chemically synthesized oligodeoxyribonucleotide fragments . The gene was ligated into plasmid pBR322 and placed under lac operon control, and N alpha-desacetylthymosin alpha 1 was expressed as part of a beta-galactosidase chimeric protein . Cyanogen bromide cleavage of this protein gave a mixture of polypeptides, among which thymosin alpha 1 activity was detected by radioimmunoassay (RIA) . The E . coli product is identical with native thymosin alpha 1 isolated from calf thymus in the amino acid sequence but lacks the N-terminal acetyl group . Results of a guinea pig migration inhibition factor (MIF) assay, a terminal deoxyribonucleotidyl transferase (TdT) assay, and radioimmunoassay indicate that the N alpha-desacetylthymosin alpha 1 produced by deoxyribonucleic acid (DNA) cloning techniques has biological activity equivalent to that of the native hormone.

Biochemistry, 1980 Dec 23, 19(26), 5973 - 81
Transfer ribonucleic acid genes in the chloroplast deoxyribonucleic acid of pea leaves; Meeker R et al.; The saturation hybridization between pea ctDNA and 125I-labeled pea ct-tRNAs has shown that 1.2% of the peak ctDNA codes for tRNA genes . The observed level of hybridization has been found to result from specific base pairings between ctDNA and ct-RNA as shown by competition hybridization experiments and thermal stability studies on DNA-tRNA hybrids . The level of hybridization obtained in this study amounts to the presence of approximately 40 tRNA genes in pea ctDNA . The tRNAs from the cytoplasm of the pea leaves, Escherichia coli, yeast, and calf thymus did not compete with the pea ct-tRNAs for the common base sequences in pea ctDNA . The presence of 17 aminoacyl-tRNA synthetases and their corresponding tRNAs was demonstrated in chloroplast . The acylation of ct-tRNAs proceeds with the same rate whether the partially purified tRNA synthetases from chloroplasts of E . coli are used . The aminoacylation of the three amino acids glutamic acid, glutamine, and cysteine proceeded very slowly in chloroplasts . The individually labeled aminoacyl-tRNAs hybridized with pea ctDNA . The hybridization follows true saturation rates, and the melting profiles of aminoacyl-tRNA-ctDNA indicate the formation of specific base pairs between the ctDNA and tRNA . Seventeen aminoacyl-tRNA genes have been identified in the pea ctDNA.

Biochemistry, 1980 Dec 23, 19(26), 6146 - 51
Interaction of Escherichia coli host factor protein with Q beta ribonucleic acid; de Haseth PL et al.; The affinity of Escherichia coli host factor protein for a variety of ribonucleic acids (RNAs) is compared in an equilibrium competition assay with (pA)15 or (pA)27 as the common probe . Of the homopolymers tested, only polyriboadenylate {poly(rA)} binds the protein with a high affinity . At low ionic strength (0.1 M NaCl), the binding to Q beta RNA is much stronger than to the oligoadenylates, but the situation is reversed upon fragmentation of the RNA with ribonuclease T1 . Increasing the ionic strength results in a drastic reduction of the affinity of host factor for Q beta RNA over a relatively narrow salt range (0.1--0.3 M NaCl) . Over the same range, added salt greatly reduces the tendency of host factor hexamers to aggregate . The tight binding of host factor to Q beta RNA is proposed to result from the binding of an aggregate, which can interact with several low affinity sites on the RNA simultaneously.

Biochemistry, 1980 Dec 23, 19(26), 6138 - 46
Interaction of Escherichia coli host factor protein with oligoriboadenylates; de Haseth PL et al.; The interaction of Escherichia coli host factor 1 with oligoadenylate {oligo(A)} was studied by fluorescence and filter retention techniques . The intrinsic fluorescence of the host factor is quenched by up to 60% by the addition of oligo(A) . Fluorescence titrations at high protein concentrations (6 microM) give a saturation point of 14 A residues per host factor hexamer regardless of chain length or ionic strength . Nitrocellulose filter retention experiments at much lower concentrations (1 nM) indicate equimolar complexes form between (pA)l (12 less than l less than 27) and host factor hexamers . The smallest number of contiguous A residues which allows the formation of all favorable protein--RNA contacts is 16 at both low and high salt concentrations . At 0.1 M NaCl, the molar association constants are in the range of 10(10)--10(11) M-1 (15 less than l less than 27) and decrease only slightly with ionic strength, indicating a large nonionic component in the interaction . Cyclized (pA)l was shown to have a higher affinity for host factor than its linear counterparts when l is 18 or greater but a lower relative affinity when l is 15 . This suggests that the binding site on the hexamer has a circular spatial orientation.

Biochemistry, 1980 Dec 23, 19(26), 5947 - 54
Distances between 3' ends of ribosomal ribonucleic acids reassembled into Escherichia coli ribosomes; Odom OW Jr et al.; The three ribonucleic acids (RNAs) from Escherichia coli ribosomes were isolated and then labeled at their 3' ends by oxidation with periodate followed by reaction with thiosemicarbazides of fluorescein or eosin . Ribosomal subunits reconstituted with the labeled RNAs were active for polyphenylalanine synthesis . The distances between the 3' ends of the RNAs in 70S ribosomes were estimated by nonradiative energy transfer from fluorescein to eosin . The percentage of energy transfer was calculated from the decrease in fluorescence lifetime of fluorescein in the quenched sample compared to the unquenched sample . Fluorescence lifetime was measured in real time by using a mode-locked laser for excitation and a high-speed electrostatic photomultiplier tube for detection of fluorescence . The distances between fluorophores attached to the 3' ends of 16S RNA and 5S RNA or 23S RNA were estimated to be about 55 and 71 A, respectively . The corresponding distance between the 5S RNA and 23S RNA was too large to be measured reliably with the available probes but was estimated to be greater than 65 A . Comparison of the quantum yields of the labeled RNAs free in solution and reconstituted into ribosomal subunits suggests that the 3' end of 16S RNA does not interact appreciably with other ribosomal components and may be in a relatively exposed position, whereas the 3' ends of the 5S RNA and 23S RNA may be buried in the 70S ribosomal subunit.

Nucleic Acids Res, 1980 Dec 20, 8(24), 6199 - 211
A DNA glycosylase from Escherichia coli that releases free urea from a polydeoxyribonucleotide containing fragments of base residues; Breimer L et al.; A poly (dA, {2-14C}dT) copolymer has been synthesized using terminal deoxynucleotidyltransferase . Treatment of the polydeoxyribonucleotide with potassium permanganate converts the thymine residues to urea and N-substituted urea derivatives, while the adenine residues are resistant to oxidation . This damaged polymer has been annealed with an equimolar amount of poly (dT) to generate a double-stranded polydeoxyribonucleotide containing scattered fragmented base residues, which are radioactively labeled selectively . On incubation of the latter with crude cell extracts from E . coli, free urea is released by a DNA glycosylase activity . The enzyme has been partly purified, and appears to be different from previously studied DNA glycosylase . It shows a strong preference for a double-stranded substrate, exhibits no cofactor requirement, and has a molecular weight of 20000 - 25000 . Since fragmentation of pyrimidine residues is a major type of base lesion introduced in DNA by exposure to ionizing radiation, it seems likely this DNA glycosylase is active in repair of X-ray-induced lesions.

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