Int J Biochem, 1985, 17(10), 1125 - 8 Studies on N-acetylneuraminic acid biosynthesis in chicken liver and hepatoma Mc-29 by using {14C}N-acetylmannosamine and {14C}glucosamine; Ivanov S et al.; The biosynthesis of free N-acetylneuraminic (sialic) acid (N-acetylneuraminic + CMP-N-acetylneuraminic acid) in chicken liver and hepatoma Mc-29 by using {14C}N-acetylmannosamine and {14C}glucosamine was studied in vivo . The specific activity (SA) of hepatoma N-acetylneuraminic acid labelled with {14C}glucosamine is lower than that of liver, showing that the rate of conversion of UDP-N-acetylglucosamine to N-acetylneuraminic acid is reduced in tumor cells . The biosynthesis rate of sialic acid in hepatoma cells is higher when {14C}N-acetylmannosamine was applied . The UDP-N-acetylglucosamine-2'-epimerase activity was nearly 3-fold lower in hepatoma compared to that in liver . The time course of {14C}N-acetylmannosamine incorporation into free and protein bound sialic acid in hepatoma and liver was also showed . The SA of hepatoma protein bound sialic acid remained lower in all time points investigated . The results agree with the assumption that the metabolic pathways leading to sialic acid synthesis and to sialylation of tumor glycoconjugates are altered after malignant transformation. Clin Ther, 1985, 7(5), 607 - 10 Transfer of cefoperazone into human skin fluid; Sugiyama H et al.; The transfer of cefoperazone into exudates from excoriated skin wounds was studied in 13 adolescent and adult patients . Subjects were given an intravenous bolus injection of 50 mg/kg of body weight . Concentrations of cefoperazone in serum and in exudate fluids were determined by bioassay using Escherichia coli as the test organism . Mean (+/- SD) cefoperazone concentration in serum reached 333.3 +/- 103.3 micrograms/ml 30 minutes after the injection and decreased to 16.4 +/- 5.7 micrograms/ml eight hours after the injection . In exudate fluids, the peak value was 52.7 +/- 22.1 micrograms/ml at one hour . Eight hours after the injection, the mean concentration in the exudate was 10.7 +/- 7.2 micrograms/ml, which was considerably above the minimum inhibitory concentrations for important pathogens. Prog Clin Biol Res, 1985, 189, 241 - 9 Ideal properties of a LAL reagent for pharmaceutical testing; Cooper JF; Evaluation of medical devices and pharmaceutical products for endotoxin content is the most significant biomedical application of Limulus amebocyte lysate (LAL) . This review summarizes the means by which LAL reagent suppliers have introduced different production techniques and formulation additives to uniquely optimize their products for industry . Pharmaceutical testing requires a LAL reagent that is buffered, stabilized to a sensitivity of 0.12 EU/ml, optimized to detect E . coli-derived LPS in water, formulated to produce firm opaque gels, designed specifically to detect bacterial endotoxin, and is economical . Unique LAL reagent characteristics produce nonuniformity in drug compatibility testing but does not significantly alter detection of unsafe levels of native endotoxin . Design of a clinical LAL reagent may require additional means for standardization and exclusion of additives which are only useful for pharmaceutical testing . A cooperative effort between clinical investigators and the LAL industry should resolve these issues in a reasonable period of time. Res Exp Med (Berl), 1985, 185(2), 107 - 13 Endotoxin-induced acute renal failure in mice . Effects of indomethacin and the thromboxane-synthetase antagonist UK 38.485; Hirschberg R et al.; Functional acute renal failure (ARF) was induced within 24 h following i.p . injection of 200 micrograms E . coli endotoxins (ET) into C3H/HeHan mice . Pre- and post-treatment with either UK 38.485, a selective thromboxane (TX)-synthetase inhibitor, or with the cyclo-oxigenase inhibitor, indomethacin (IM), does not prevent acute renal failure in these mice . Histologically, only very little fibrin degradation and few microthrombi are present 24 h later in the kidneys, so that disseminated intravascular coagulation (DIC) mechanisms cannot have caused the significant azotemia . Slight histological changes are accentuated in the UK 38.485-treated group . Only the indomethacin group has a significantly increased mortality as compared to all other groups . We conclude from our study that with low dosages of endotoxins functional ARF can be induced in mice without a circulatory shock and early mortality and that both UK 38.485 and IM are of little value in preventing it. J Cell Biol, 1985 Jan, 100(1), 258 - 64 Purification and general properties of the DNA-binding protein (P16) from rat liver mitochondria; Pavco PA et al.; The mitochondrial DNA-binding protein P16 was isolated from rat liver mitochondrial lysates by affinity chromatography on single strand DNA agarose and separated from DNA in the preparation by alkaline CsCl isopycnic gradients . The top fraction of the gradients contained a single polypeptide species (Mr approximately equal to 15,200) based upon SDS PAGE . Digestion of single strand DNA-bound P16 with proteinase K produced a protease-insensitive, DNA-binding fragment (Mr approximately equal to 6,000) that has been purified by essentially the same procedures used for intact P16 . The partial amino acid compositions for P16 and the DNA-binding fragment were obtained by conventional methods . Analysis of subcellular fractions revealed that nearly all of the cellular P16 was located in the mitochondria and that only trace amounts of protein of comparable electrophoretic mobility could be isolated from the nuclear or cytoplasmic fractions . The labeling of P16 with {35S}methionine in primary rat hepatocyte cultures was inhibited by more than 90% by the cytoplasmic translation inhibitor cycloheximide, but unaffected by the mitochondrial-specific agent chloramphenicol . These results indicate that P16 is synthesized on cytoplasmic ribosomes and imported into the mitochondria . The addition of purified P16 to deproteinized mitochondrial DNA resulted in the complete protection of the labeled nascent strands of displacement loops against branch migrational loss during cleavage of parental DNA with SstI, thus providing strong evidence that P16 is the single entity required for this in vitro function . Incubation of P16 with single strand phi X174 DNA, double strand (RF) phi X174 DNA, or Escherichia coli ribosomal RNA and subsequent analysis of the nucleic acid species for bound protein indicated a strong preference of P16 for single strand DNA and no detectable affinity for RNA or double strand DNA . Examination of P16-single strand phi X174 DNA complexes by direct electron microscopy revealed thickened, irregular fibers characteristic of protein-associated single strand DNA. Dev Biol Stand, 1985, 59, 175 - 80 Control of recombinant DNA produced pharmaceuticals by a combination of process validation and final product specifications; Jones AJ et al.; Traditional methods of product release for human pharmaceutical use are designed and selected to ensure control of purity, potency, safety and identity . The selection of these tests depends upon the nature of the product . In addition to the control achieved by these methods, control of the efficiency of the manufacturing process in removing substances that cannot be tested for in the final product is achieved by "process validation" . Process validation allows the use of sophisticated experimental techniques that do not lend themselves to final product testing or the use of others which, when applied to the final product, are insufficiently sensitive to be used for product release . The removal of such components as DNA and process materials can be demonstrated by these studies . Demonstrations that the manufacturing process reproducibly removes these components, eliminate the need for these tests on every batch . The essential elements of a process validation study are development of a sensitive assay technique for the component of interest and quantitation of the efficiency of individual process steps in removing that component . Even when that component is undetectable in normal process samples, the efficiency of any process step can still be determined by the addition of that component during the validation studies . The values of process validation in demonstrating the removal of DNA and in the determination of E . coli protein contamination levels during the manufacture of methionyl human growth hormone is illustrated. Jpn J Antibiot, 1985 Jan, 38(1), 95 - 101 {Fundamental studies of cefoxitin in the field of obstetrics and gynecology}; Ito K et al.; The concentration of cefoxitin (CFX, Merxin) in dead space exudate was studied in 14 patients following total extirpation of diffuse uterine cervical cancer . A two-compartment model was used for the analysis . The results obtained were as follows: Calculated maximum concentrations of CFX in the pelvic dead space exudate were 26.55 micrograms/ml at 2.11 hours, 31.07 micrograms/mg at 2.01 hours and 51.51 micrograms/ml at 2.10 hours after 1 hour intravenous drip infusions of CFX 2, 3 and 4 g, respectively . These concentrations were higher than the MIC80 of 12.5 micrograms/ml against E . coli and B . fragilis and were maintained for a sufficient period of time . Based on the results of this study, CFX is considered to be an important and valuable drug in the field of obstetrics and gynecology. Arch Microbiol, 1985 Jan, 140(4), 343 - 6 Functional domains of colicin M; Dreher R et al.; The structure of colicin M of Escherichia coli was studied with regard to its organization into functional domains . A proteolytic fragment with an Mr of 24,000 was isolated which comprised the carboxyterminal portion of the protein . It adsorbed to the outer membrane receptor protein and inhibited killing of cells by colicin M and by phage T5 that uses the same receptor . The fragment killed cells when the outer membrane was rendered permeable to macromolecules for a short time by the osmotic shock procedure . It is concluded that the fragment contains the receptor binding site and the active center but is lacking the sequence required for transport into cells . The carboxy-terminal amino acid sequence-Lys-Arg of the fragment was identical to that obtained from colicin M . Release of lysine and arginine led to inactivation of colicin M . The sequence of the first 39 amino acids of the amino terminal end of colicin M was determined. Mol Cell Biol, 1985 Jan, 5(1), 140 - 6 Selective transfer of individual human chromosomes to recipient cells; Saxon PJ et al.; Two hypoxanthine phosphoribosyltransferase-deficient human cell lines, D98/AH-2 and HT1080-6TG, were stably transfected with pSV2 gpt, a plasmid containing the selectable marker Escherichia coli xanthine-guanine phosphoribosyl transferase (Eco gpt) . Hypoxanthine-aminopterin-thymidine-resistant transformants arose with a frequency of ca . 10(-6) and contained mostly single, but occasionally multiple, copies of the plasmid sequences . These transformants actively express the Eco gpt marker . Single chromosomes from two different HT1080 gpt transformants and one D98 gpt transformant, containing the integrated plasmid sequences, were transferred via microcell-mediated chromosome transfer to hypoxanthine phosphoribosyl transferase-deficient mouse A9 cells . The transferred human chromosomes were identified as 2, 4, and 22, by using a combination of G-11 staining, G-banding, isoenzyme analysis, and in situ hybridization . This system is being used to create a library of interspecies microcell hybrid clones, each clone containing a unique single human chromosome in a mouse background . The complete library will represent the entire human karyotype. Int Arch Allergy Appl Immunol, 1985, 76(4), 324 - 30 Immune responses to polyethylene glycol modified L-asparaginase in mice; Kawamura K et al.; Suppression of anti-L-asparaginase (anti-A-ase) IgG and IgE antibody responses was achieved in Balb/c mice with polyethylene glycol (PEG, MW, 5,000) conjugated Escherichia coli A-ase . Following the administration of the mixture of A-ase and PEG-A-ase, antibody production to A-ase was reduced . PEG-A-ase administration prior to A-ase suppressed the primary and secondary responses to A-ase antibody . The suppression could be transferred to normal mice with spleen cells from A-ase tolerant mice . The cell transfer experiment showed that the suppression was caused by suppressor T cells . Since PEG-A-ase administration failed to suppress antibody response to ovalbumin, the suppression seemed to be A-ase specific . PEG-A-ase administration also suppressed the delayed type hypersensitivity reaction . IgG and IgE antibodies to PEG or PEG-A-ase were not detected in mice immunized with PEG or PEG-A-ase in the presence of Freund's complete adjuvant or A1(OH)3, respectively. Radiobiologiia, 1985 Jan-Feb, 25(1), 95 - 9 {Stimulating effect of aminoethylisothiuronium on the immune response and interferonogenesis in irradiated mice}; Zheleznikova GF et al.; Aminoethylisothiuronium (AET) stimulated the formation of antibodies against sheep erythrocytes, not against E . coli, in X-irradiated (4 Gy) mice . The serum containing AET-induced interferon had the same effect . AET also promoted the rejection of the allogenic skin graft in mice irradiated with the same dose . In addition, AET and cystaphos stimulated the induction of interferon by the Newcastle disease virus in mice exposed to doses of 4, 5 or 6 Gy. J Appl Physiol, 1985 Jan, 58(1), 70 - 6 Effect of outflow pressure on lung lymph flow in unanesthetized sheep; Drake R et al.; Studies in anesthetized animals have shown that the flow rate from lung lymphatics (QL) depends on the pressure at the outflow end of the vessels (Po) . We tested this in unanesthetized sheep prepared with chronic lung lymph cannula . We measured QL with the lymph cannula held at various heights above the olecranon and calculated Po as the height + QL X cannula resistance . QL decreased with increases in Po (delta QL/delta Po = -8.2 +/- 6.4 microliter X min-1 X cmH2O-1, mean +/- SD) . We increased QL by raising left atrial pressure or infusing Ringer solution or Escherichia coli endotoxin and found that QL was even more sensitive to Po (delta QL/delta Po = -32 +/- 22) . Cannula resistance caused a 9-70% reduction in QL . Changes in QL caused by increasing Po were not associated with changes in lymph protein concentration for up to 330 min . This indicates that increases in Po shunt lymph away from cannulated vessels but do not substantially effect microvascular filtration rate . The shunted lymph may flow into other vessels or collect in the lung . We conclude that QL does not accurately represent microvascular filtration rate because it depends on the cannula resistance and position at which the investigator chooses to place the cannula. Carcinogenesis, 1985 Jan, 6(1), 105 - 8 The role of DNA-repair processes in N-nitrosopyrrolidine-induced mutagenesis; Alldrick AJ et al.; The cytotoxic and mutagenic effects of increasing concentrations of N-nitrosopyrrolidine (NPYR) were studied using various DNA repair mutants of Escherichia coli together with rat-liver S9 activation system . Irrespective of which strain was used, the cytotoxic effects of NPYR were similar to those observed in the parent strain . Mutagenicity studies revealed that the uvrA- derivative was more mutable than its repair proficient parent . These observations suggest that NPYR reacts with DNA to generate bulky lesions, which although potentially mutagenic, do not contribute significantly to cell-killing . Subsequent experiments with the metabolic inhibitor SKF 525A revealed that this compound only partially inhibited the mutagenic activity of NPYR, suggesting that although hepatic mixed function oxidase enzymes may participate in NPYR activation other pathways of metabolism are also involved. Infect Immun, 1985 Jan, 47(1), 329 - 31 Metabolic and mitochondrial morphological changes that mimic Reye syndrome after endotoxin administration to rats; Yoder MC et al.; The administration of sublethal doses of Escherichia coli O111:B4 endotoxin to starved rats results in significant increases in plasma ammonia, free fatty acids, and serum lactate compared with starved controls . These metabolic alterations are associated with Reye syndrome-like histological findings of hepatic microvesicular fatty accumulation and hepatic ultrastructural evidence of mitochondrial pleomorphism with matrix disruption . This sublethal endotoxin model may help elucidate the relationship between the hepatic mitochondrial injury, characteristic metabolic impairment, and encephalopathy seen in patients with Reye syndrome. J Cell Sci Suppl, 1985, 3, 29 - 38 Production of epidermal growth factor in Escherichia coli from a synthetic gene; Allen G et al.; Mouse epidermal growth factor (EGF) is under investigation as a deflecting agent for sheep . Substantial quantities of the pure protein are required for these studies and to supply this need a gene for the protein was synthesized and inserted into plasmid vectors to direct the expression of EGF polypeptide, or fusion proteins containing the EGF peptide sequence, in transformed Escherichia coli . Mature EGF was released by lysine specific proteolysis of a fusion protein consisting of part of the E . coli TrpE protein, a lysine linker and EGF polypeptide . The EGF was purified and characterized and was found to be biologically active. Gene, 1985, 40(2-3), 291 - 9 Conservation of a 29-base-pair sequence within maxicircle ARS fragments from six species of trypanosomes; Kim R et al.; The maxicircles from Trypanosoma brucei, Herpetomonas samuelpessoai, Leptomonas seymouri, and Phytomonas davidi were examined for the presence of a 29-bp sequence termed CF29 that has been found in the ars 189 sequence from the Crithidia fasciculata maxicircle and in Lt-ars 189 from the maxicircle of Leishmania tarentolae . The CF29 sequence also contains a yeast consensus ARS of (T/A)TTTATPuTTT(T/A) . All of the maxicircles examined contained specific fragments that hybridized to the CF29 probe . The non-replicating yeast plasmid vector YIp5 was used to clone these CF29-containing maxicircle fragments . High-frequency transformation was observed when these chimeric plasmids were used to transform Saccharomyces cerevisiae . Autonomous replication of these transforming plasmids was verified by Southern analysis of yeast-cell extracts using pBR322 as a hybridization probe . Therefore it appears that the CF29 sequence is widely conserved in kinetoplastid protozoa and is associated with ARS sequences in the maxicircles . Hybridization of the CF29 probe to a population of P . davidi minicircles was also observed . However, the YIp5 chimeric plasmid containing this CF29-hybridizing minicircle fragment failed to transform yeast. Gene, 1985, 40(2-3), 203 - 15 Characterization of nif regulatory genes in Rhodopseudomonas capsulata using lac gene fusions; Kranz RG et al.; Translational fusions of the Escherichia coli lacZYA operon to Rhodopseudomonas capsulata nif genes were obtained by using mini-MudII1734 {Castilho et al., J . Bacteriol . 158 (1984) 488-495} inserts into cloned fragments of R . capsulata DNA . A lac fusion to the nifH gene, which encodes dinitrogenase reductase, was used to classify Nif- mutations occurring in regulatory genes . Nine mutations were unable to activate nifHDK transcription . The nine mutations define four nif regulatory genes . Three of these genes are located on the same R . capsulata 8.4-kb EcoRI fragment . Each is transcribed independently . One of these (complementing mutant J61) is partially homologous with the ntrC gene of Escherichia coli, based on Southern hybridization . The fourth nif regulatory gene (complementing mutants LJ1, AH1 and AH3) is unlinked to the others . Lac fusions to all four regulatory genes were constructed . Each regulatory gene is weakly expressed compared to derepressed nifH and partially repressed in the presence of ammonia. Gene, 1985, 39(2-3), 269 - 74 Cloning and expression in Escherichia coli of the synthetic proenkephalin analogue gene; Hostomsky Z et al.; Enkephalins are pentapeptides with opioid activity that have been found in brain and other neural tissues . They are released by proteolytic processing of the proenkephalin, which contains several enkephalin sequences each flanked by pairs of basic amino acid (aa) residues . We have constructed an artificial variant of the proenkephalin gene by concatenation of synthetic oligodeoxynucleotides (oligo) coding for Met-enkephalin preceded by two arginines . One of the resulting structures, containing eleven enkephalin sequences separated by pairs of arginine codons, was cloned in the expression vector pRE31 . The biological activity of enkephalin was detected after the digestion of the isolated plasmid-coded protein with trypsin and carboxypeptidase B . The product of the synthetic gene may thus serve as a defined simplified substrate for the study of the not yet fully understood enzymatic mechanisms of proenkephalin processing. Gene, 1985, 39(2-3), 147 - 53 Shuttle vectors to study somatic mutagenesis and regulation of gene expression in the immune system; Lazo PA; Somatic mutagenesis is one of the main mechanisms for generation of diversity in the immunoglobulin genes . A family of 16 shuttle vectors has been designed to identify the mutation mechanism . These vectors are based on bovine papilloma virus replicon and carry selective markers (NmR and ApR), a mutation marker (the Escherichia coli galK) as well as several segments from the immunoglobulin (Ig) heavy- and kappa light-chain genes in different orientations . They can also be used to study general mutagenesis and the relative contribution of different DNA sequences to the regulation of gene expression by competition with trans-acting factors . These vectors start replicating in mammalian cells two days after transfection . Stable transformants carry the plasmids in an extrachromosomal form for at least three months without evidence of structural alteration. Nucleic Acids Symp Ser, 1985, (16), 287 - 90 Synthesis and expression of the native RNase T1 gene and several mutant genes; Nishikawa S et al.; RNase T1 gene and several mutant genes were constructed by joining of chemically synthesized deoxyoligonucleotides . These genes were inserted into an expression vector and expressed as fused protein in E . coli . RNase T1 and its mutant enzymes were liberated by cyanogen bromide treatment and their activities were measured. Mol Gen Genet, 1985, 201(3), 519 - 24 Ability of base analogs to induce the SOS response: effect of a dam mutation and mismatch repair system; Bebenek K et al.; 2-Aminopurine, 2-amino-N6-hydroxyadenine, 2-amino-N6-methoxyadenine and 2-amino-N6-methyl-N6-hydroxyadenine (but not N4-hydroxycytidine), strong mutagens of base analog type, may induce the SOS response in E . coli cells . This ability is greatly enhanced in dam3 mutants and abolished in dam3mutS, dam3mutH, and dam3mutL strains, thereby suggesting that the mismatch repair system is involved in the mechanism of induction. J Mol Evol, 1985, 22(4), 361 - 2 A change in the genetic code in Mycoplasma capricolum; Jukes TH; Mycoplasma capricolum was previously found to use UGA instead of UGG as its codon for tryptophan and to contain 75% A + T in its DNA . The codon change could have been due to mutational pressure to replace C + G by A + T, resulting in the replacement of UGA stop codons by UAA, change of the anticodon in tryptophan tRNA from CCA to UCA, and replacement of UGG tryptophan codons by UGA . None of these changes should have been deleterious. Gene, 1985, 36(3), 375 - 9 The effects of hybrid ribosome-binding-site variants on the expression of human interferon-beta in Escherichia coli; Whitehorn EA et al.; Human beta-interferon (IFN-beta) has been expressed in Escherichia coli by using vectors that join the trp promoter and a hybrid ribosome-binding site (HRBS) to the mature IFN-beta coding sequence . Introduction of an NcoI site at the ATG initiation codon of IFN-beta by site-directed mutagenesis has facilitated the construction of a series of portable HRBSs, by utilizing oligodeoxynucleotide adapters . The spacing between the Shine-Dalgarno (S-D) sequence and the initiator ATG ranged from 7-13 bp . One spacer of 9 bp length was varied at a single position . IFN-beta expression by these HRBS variants, as analyzed by antiviral activity and SDS-PAGE, shows both nucleotide sequence and spacer length effects . In vitro transcription-translation experiments indicate that some single base changes in the HRBS significantly decrease the rate of translation of the IFN-beta mRNA. Gene, 1985, 36(1-2), 159 - 67 The use of gene fusions to study the expression of uidR, a negative regulatory gene of Escherichia coli K-12; Blanco C et al.; The uidR regulatory gene of Escherichia coli codes for a repressor molecule that negatively controls the expression of the uidA gene . The uidR gene was fused in front of the lacZ gene in vitro on plasmid cloning vectors developed by Casadaban et al . {J . Bacteriol . 143 (1980) 971-980 . The transcriptional direction of uidR was deduced from the restriction pattern and the phenotypic properties of the uidR-lacZ fusion plasmids . The gene is transcribed counterclockwise on the standard E . coli map, as is the uidA gene . The uidR-lacZ fusions were also used to examine the regulation of expression from the uidR promoter . It was observed that the uidR gene expression is repressed by its own product and is sensitive to catabolite control . The uidR-lacZ-encoded proteins of various sizes were isolated but attempts to obtain hybrid molecules possessing, in a single polypeptide, both the beta-galactosidase and UidR repressor activities were unsuccessful. Mol Gen Genet, 1985, 201(1), 14 - 9 Viability of Escherichia coli K-12 DNA adenine methylase (dam) mutants requires increased expression of specific genes in the SOS regulon; Peterson KR et al.; We have examined the level of expression of the SOS regulon in cells lacking DNA adenine methylase activity (dam-) . Mud (Ap, lac) fusions to several SOS operons (recA, lexA, uvrA, uvrB, uvrD, sulA, dinD and dinF) were found to express higher levels of beta-galactosidase in dam- strains than in isogenic dam+ strains . The attempted construction of dam- strains that were also mutant in one of several SOS genes indicated that the viability of methylase-deficient strains correlates with the inactivation of the SOS repressor (LexA protein) . Consistent with this, the wild-type functions of two LexA-repressed genes (recA and ruv) appear to be required for dam- strain viability. Int J Nucl Med Biol, 1985, 12(2), 135 - 44 111In-labeled eosinophils: localization of inflammatory lesions and parasitic infections in mice; Runge VM et al.; Based upon recent development of practical isolation techniques for eosinophils, labeling and in vivo imaging of eosinophils has been achieved . Isolation of cells was performed utilizing a Percoll density gradient . The eosinophils were subsequently labeled by a modified 111In-oxine method . Migration of eosinophils in response to intradermal ear-pinna injections of SEA (soluble schistosoma egg antigen), S . mansoni eggs, E . coli, and turpentine was followed with gamma-ray camera imaging from 4 to 48 h . Maximal localization, determined by Gamma 11 data processing, occurred by 4-h post-injection of radiolabel . SEA and S . mansoni eggs provided a greater stimulus for localization than E . coli or turpentine . Neutrophils did not preferentially accumulate . Tissue distribution of labeled eosinophils was greatest in the spleen, followed by liver and bone . 111In-labeled-eosinophil scans are sensitive to parasitic infections, although somewhat nonspecific. Mol Gen Genet, 1985, 200(1), 185 - 6 DNA methylation influences trpR promoter activity in Escherichia coli K-12; Marinus MG; Methylation of adenine in the GATC-sequence of the -35 region of the trpR promoter decreases activity by 2-3 fold. Mol Gen Genet, 1985, 199(3), 507 - 11 Genetic analysis of uxuR and exuR genes: evidence for ExuR and UxuR monomer repressors interactions; Ritzenthaler P et al.; The uxuAB operon is under the dual control of uxuR- and exuR-encoded repressors whereas the exu regulon genes are regulated by the sole ExuR repressor . Mutations affecting the two exuR and uxuR regulatory genes were selected to investigate the relationship between the two repressors . The isolation of exuR and uxuR negative dominant mutations on a multicopy plasmid indicated that the active form of the two repressors was multimeric . The introduction of a uxuR negative dominant allele into a wild-type strain resulted in a significant increase in exu gene expression . This unexpected effect may have been the consequence of the formation of hybrid repressor molecules . This protein must be composed of native ExuR+ subunits aggregated with altered UxuR subunits . The same interference was observed for the exuR negative dominant allele on uxu gene derepression . The hypothesis given here implies that the two regions of the ExuR and UxuR repressors involved in the subunit aggregation present enough homologies to allow the formation of hybrid repressor molecules. Gene, 1985, 35(1-2), 159 - 67 Synthesis of a wheat storage protein subunit in Escherichia coli using novel expression vectors; Bartels D et al.; Useful plasmid expression vectors have been constructed which allow the synthesis of beta-galactosidase (betaG) fusion polypeptides or of polypeptides specified by cDNA clones in Escherichia coli hosts . A foreign DNA fragment can be inserted in any one of the three reading frames at the unique EcoRI, BamHI or SmaI sites immediately after the initiation codon . The cloned foreign gene is under the control of the lac promoter . Using a cDNA clone that encodes part of a wheat storage protein {a high-Mr (HMW) glutenin subunit} synthesis of a glutenin-beta G fusion protein was demonstrated . Synthesis of the glutenin polypeptide, not fused to beta G, was achieved by replacing the lacZYA genes with a stop codon. J Immunoassay, 1985, 6(1-2), 111 - 23 A simple method for the conjugation of affinity-purified Fab' to horseradish peroxidase and beta-D-galactosidase from Escherichia coli; Hashida S et al.; A simple method was described for the conjugation of affinity-purified Fab' to horseradish peroxidase and beta-D-galactosidase from Escherichia coli . IgG was subjected to successive processes of pepsin digestion, reduction with 2-mercaptoethylamine, affinity-purification and reaction with maleimide groups introduced into the enzymes . In the present method, gel filtration was required only once to separate the conjugate from unconjugated components in the final step, while gel filtration had to be repeated 3-4 times in the previous methods . The conjugate preparations obtained by the present method contained less nonspecific conjugate and gave a lower background by immunoenzymometric assay technique than those obtained by the previous method. Mol Gen Genet, 1985, 198(3), 432 - 6 Generation of deletions through a cis-acting mutation in plasmid pC194; Alonso JC et al.; When plasmid pC194-1 is ligated to pBR322 to generate plasmid pHV15-1, deletions occur with high frequency within the joined pBR322 DNA . Generation of deletions is recE4 independent, and occurs in B . subtilis with a 1,000-fold higher frequency than in Escherichia coli . In the hybrid plasmid pVH15-1, deletion end-points are not at random, but at defined locations within pBR322 . We propose that the base alteration, characterizing pC194-1, has stabilized within the plasmid a stem/loop structure, which acts as a deletion generator. Gene, 1985, 34(1), 105 - 10 Isolation and expression in Escherichia coli of a cDNA clone encoding human beta-glucuronidase; Guise KS et al.; Mucopolysaccharidosis type VII is a lysosomal storage disease resulting from a deficiency of beta-glucuronidase (BG) activity . To facilitate the investigation of mutation in the disease and provide molecular diagnostic tools for affected families, we have isolated human BG cDNA clones . The SV40-transformed human fibroblast cDNA library of Okayama and Berg {Mol . Cell . Biol . 3 (1982) 280-289} was screened with a fragment of a murine BG cDNA clone (pGUS-1) . The 17 human cDNA clones (pHUG) isolated were identical by restriction mapping, varying only in length . The pHUG clones show 80% DNA sequence homology with pGUS-1 in a 198-bp PvuII-SstI restriction fragment . Both pGUS-1 and the pHUG clones contained an open reading frame (ORF) throughout the sequenced region with a predicted amino acid sequence homology of 73% . Expression in Escherichia coli of a 1150-bp fragment of pHUG-1 subcloned in pUC9 resulted in an isopropyl-thio-beta-galactoside (IPTG)-inducible 35-kDal fusion protein which was specifically immunoprecipitated by goat anti-human BG immunoglobulin G (IgG) . This evidence provides direct confirmation that the pHUG cDNA clones correspond to human BG. Ann Inst Pasteur Microbiol, 1985 Jan-Feb, 136A(1), 139 - 45 Stimulation and inhibition of cell division in synchronized Escherichia coli; Nanninga N et al.; Escherichia coli was synchronized by centrifugal elutriation . When grown in a Tris-based medium, addition of EDTA resulted in division about 20 min earlier (division of control at t = 75 min) . EDTA addition caused a change in cell shape, with cells becoming narrower and longer, whereas the surface area to volume ratio increased . Irradiation with UV inhibited not only division and constriction, but also the increase in DAP incorporation found in dividing control cells . Possibly, division requires the construction of new polar caps, whereas premature division might involve remodeling of existing murein . In both cases, cell shape is presumed to be a relevant factor for division. C R Acad Sci III, 1985, 300(7), 255 - 60 {Construction of an infectious retroviral vector for the expression of eucaryotic genes}; Yeramian P et al.; We describe here an infectious eucaryotic expression vector derived from Moloney Murine Leukemia (Mo-MuLV) provirus and recombined in plasmid pBR 322, for the expression of eucaryotic genes . Upstream of the cloning sites lie the 5' LTR and 700 bp of the gag sequences containing the splicing and encapsidation signals . Downstream of the cloning sites are situated the env gene and the 3' LTR containing the polyadenylation signal . So as to test the potential use of this vector, Herpes Simplex TK gene and E . Coli NeoR genes were cloned in the same transcriptional polarity as the viral LTRs . When DNA from the recombinant plasmid was transfected into mouse, rat, or human cell cultures, high yields of TK+ or NeoR colonies were obtained . Recombinant plasmids constructed with TK or NeoR genes in the opposite polarity failed to produce drug resistant colonies . Cotransfection with DNA of the Mo-MuLV competent helper provirus led to the rescue of chimeric virus capable of transmitting drug resistance. Biochimie, 1985 Jan, 67(1), 75 - 82 Does a monospecific hybridoma always secrete homogeneous immunoglobulins? Chaffotte AF, Djavadi-Ohaniance L, Goldberg ME. The fusion of splenocytes (from mice immunized with the beta 2 subunit of E . coli tryptophan synthase) with myeloma cells which do not produce immunoglobulins gave rise to a clone secreting immunoglobulins with two distinct isotypes : gamma 1 and gamma 2b (Djavadi-Ohaniance et al . (1984) Biochemistry, 23, 97-104) . Analysis of the immunoglobulins secreted by this clone indicates that these two isotypes are carried by two distinct heavy chains which are able to randomly associate to form hybrid molecules . In addition, two classes of light chains are able to randomly and to form heterologous associations with both the gamma 1 and gamma 2b heavy chains . Only the association between the gamma 2b heavy chains with one of the two classes of light chains leads to a combining site specific for the binding of the antigen beta 2. Biochimie, 1985 Jan, 67(1), 101 - 8 The amino acid sequence of thiogalactoside transacetylase of Escherichia coli; Fowler AV et al.; The amino acid sequence of thiogalactoside transacetylase, a dimer, has been determined . The monomer contains 202 amino acid residues in a single polypeptide chain and has a molecular weight of 22,671 . The analysis was carried out by treatment of the carboxymethylated protein with cyanogen bromide and with trypsin . All seven cyanogen bromide peptides were isolated in pure form and were ordered by peptides isolated from tryptic digests . The sequence analysis was aided by determination of the DNA sequence of the lacA gene . The amino terminus of the protein is heterogenous because the initiator methionine is only partially cleaved . Another rather unusual feature of this cytoplasmic protein is a very hydrophobic segment in the center portion of the chain . Comparison of the amino acid sequence of thiogalactoside transacetylase to those of the lac repressor, beta-galactosidase, and lactose permease did not reveal any marked similarities . Therefore, there is no obvious evolutionary relatedness among proteins of the Lactose Operon. Mol Cell Biol, 1985 Jan, 5(1), 197 - 203 The heat shock consensus sequence is not sufficient for hsp70 gene expression in Drosophila melanogaster; Amin J et al.; A hybrid gene in which the expression of an Escherichia coli beta-galactosidase gene was placed under the control of a Drosophila melanogaster 70,000-dalton heat shock protein (hsp70) gene promoter was constructed . Mutant derivatives of this hybrid gene which contained promoter sequences of different lengths were prepared, and their heat-induced expression was examined in D . melanogaster and COS-1 (African green monkey kidney) cells . Mutants with 5' nontranscribed sequences of at least 90 and up to 1,140 base pairs were expressed strongly in both cell types . Mutants with shorter 5' extensions (of at least 63 base pairs) were transcribed and translated efficiently in COS-1 but not at all in D . melanogaster cells . Thus, in contrast to the situation in COS-1 cells, the previously defined heat shock consensus sequence which is located between nucleotides 62 and 48 of the hsp70 gene 5' nontranscribed DNA segment is not sufficient for the expression of the D . melanogaster gene in homologous cells . A second consensus-like element 69 to 85 nucleotides upstream from the cap site is postulated to be also involved in the heat-induced expression of the hsp70 gene in D . melanogaster cells. Mol Gen Genet, 1985, 198(2), 356 - 7 Identification of a gene, tir of R100, functionally homologous to the F3 gene of F in the inhibition of RP4 transfer; Tanimoto K et al.; We detected a gene of R100 functionally homologous to the F3 gene of F in the inhibition of RP4 transfer . Using in vitro recombinant DNA techniques, we located the gene, designated tir, in a 0.9 kb region, 2,392-3,293 in the nucleotide sequence coordinate of R100 . From the DNA sequence analysis of R100 (Ohtsubo unpublished results), a coding frame of polypeptides, whose molecular weight is estimated to be 24.1 kilodaltons (kd), was inferred to be the region tir . Furthermore, we showed that tir could not repress expression of the F3 gene. Mol Gen Genet, 1985, 198(2), 315 - 22 Identification of the dadX gene coding for the predominant isozyme of alanine racemase in Escherichia coli K12; Wild J et al.; Evidence is presented that alanine racemase activity in E . coli K12 is due to two distinct gene products . The predominant isozyme is inducible by either alanine stereoisomer and repressible by glucose . The gene dadX coding for its structure is located by the dadA gene determining the structure of D-amino acid dehydrogenase . The regulatory site for the expression of both genes, dadR, is located on the other side of dadA . The orientation of the dad operon established by multiple-point crosses and deletion mapping is as follows: fadR ...dadRAX ...hemA . The dadX alanine racemase activity is unusually refractory to changes of incubation temperature . It differs strikingly from that of the other isozyme, probably the product of the alr gene . The latter isozyme shows a typical dependence upon incubation temperature . The synthesis of alr alanine racemase is constitutive in respect of both alanine and glucose . In dadX mutants, in which alanine racemase activity equals only 15% of that in wild-type cells grown in the absence of an inducer or catabolite repressor, the dad operon cannot be induced by D-alanine . We presume, therefore, that L-alanine is involved more directly than D-alanine in dad operon regulation. Chromosoma, 1985, 91(3-4), 259 - 66 X chromosomal organisation and dosage compensation . In situ transcription of chromatin template activity of X chromosome hyperploids of Drosophila melanogaster; Chatterjee RN; The chromatin template activity of the polytene X chromosomal DNA was assayed by in situ transcription on the fixed polytene chromosomes using E . coli RNA polymerase holoenzyme and 3H-UTP as the monitoring substrate in various 1X2A, 2X2A and 3X2A larvae and 1X2A (+ X fragments) segmental aneuploid larvae of Drosophila melanogaster . The segmental aneuploids contained duplications for the segments 15EF-20F, 11A-20F, 8C-20F and 3E-20F of the X chromosome . Results revealed that a double dose of active loci located in the X chromosome regions 15EF-20F, 11A-20F, and 8C-20F in aneuploids synthesized nearly 40%-70% more RNA than the normal single dose of this region in the wild-type males . The activity per gene dose for the two segments in the aneuploids was also significantly higher than in their male counterpart except for the duplication dp (3E-20F), where the duplicated piece extended from the centromeric heterochromatin to include 85% of the euchromatic portion of the X chromosome . In the case of dp (3E-20F), the X chromosome was transcribed at the lower, "female" level . It may also be noted that some regions of the X chromosome when present in extra copy, especially in dp (8C-20F) influenced the template activity of the X-linked genes inside or outside the duplicated segment . Metafemales (3X2A) have 50% higher template activity of the X chromosomes than their diploid sisters . In this study, metafemales behaved as females with duplication.(ABSTRACT TRUNCATED AT 250 WORDS) Circ Shock, 1985, 15(3), 205 - 15 Metabolic and cardiovascular effects of endotoxin infusion in conscious unrestrained rats: effects of methylprednisolone and BW755C; McKechnie K et al.; Infusion of Escherichia coli endotoxin (41.7 micrograms kg-1 min-1 i.v . for 4 h; 10 mg kg-1 total) in conscious unrestrained rats produced an increase in heart rate and a gradual decrease in arterial blood pressure . Initially plasma glucose was transiently elevated but fell to hypoglycaemic values in the 1-2 h before death . There was a marked elevation in the plasma concentrations of lactate, thromboxane B2, and 6-keto prostaglandin F1 alpha, (PGF1 alpha) . Methylprednisolone treatment (two doses of 30 mg kg-1) significantly reduced mortality, provided the first dose was given before commencing the endotoxin infusion; there was no effect on mortality if it was given 2 h after starting the endotoxin infusion . Methylprednisolone pretreatment maintained arterial blood pressure and plasma glucose and prevented the increase in plasma lactate in rats given endotoxin . Methylprednisolone treatment did not modify the increase in plasma thromboxane B2 but attenuated the increase in plasma 6-keto PGF1 alpha concentrations . Pretreatment with BW755C, an inhibitor of both cyclooxygenase and lipoxygenase enzymes, completely prevented the increase in plasma prostanoid concentrations but did not improve survival or significantly modify any other detrimental effects of endotoxin . It is suggested that the beneficial effects of methylprednisolone in this model of endotoxin shock are not related to a reduction in the formation of pharmacologically active arachidonic acid metabolites. Circ Shock, 1985, 15(3), 155 - 62 Endotoxin-induced eicosanoid production by equine vascular endothelial cells and neutrophils; Bottoms GD et al.; Dispersed equine vascular endothelial cells grown in tissue culture, and freshly isolated neutrophils were used to determine direct effects of endotoxin on cyclooxygenase and lipoxygenase products . Endothelial cells (10(7)/ml) or neutrophils (2 X 10(6)/ml) were incubated with (a) buffer, (b) endotoxin (10 micrograms/ml), (c) endotoxin + flunixin meglumine (10 micrograms/ml), or (d) calcium ionophore, A23187 (10 micrograms/ml) . Thromboxane (TxB2), prostacyclin (6-keto-PGF1 alpha), and leukotriene C4 (LTC4) were determined in the incubation fluid by radioimmunoassay . Thromboxane and prostacyclin levels increased in endothelial cells incubated with endotoxin . Treatment with flunixin meglumine prevented the endotoxin-induced release of these cyclooxygenase products to levels below those observed in control cells . Leukotriene production was increased in endothelial cells incubated with endotoxin plus flunixin meglumine . Endotoxin as well as endotoxin plus flunixin meglumine increased the production of prostacyclin and LTC4 by freshly isolated neutrophils . Cells exposed to endotoxin plus flunixin meglumine produced more LTC4 than cells exposed to endotoxin . The data revealed that endotoxin has a direct effect on arachidonic acid metabolism in endothelial cells and neutrophils . Flunixin meglumine reduced the level of cyclooxygenase products but increased the level of lipoxygenase products . Therefore, the well-established beneficial effects of cyclooxygenase inhibitors during endotoxemia may be improved even more if they are used in conjunction with lipoxygenase inhibitors or a combined cyclooxygenase-lipoxygenase inhibitor. Circ Shock, 1985, 15(2), 89 - 103 Benoxaprofen attenuation of lethal canine endotoxic shock; Toth PD et al.; Our prior work demonstrated in a canine endotoxic shock model (LD100) that the cyclooxygenase inhibitor ibuprofen given 60 minutes after endotoxin administration could improve hemodynamics but not survival over control animals . The present study was designed to examine the effect of benoxaprofen, a dual lipoxygenase and cyclooxygenase inhibitor, in the same canine endotoxic model (LD100) and compare it to ibuprofen treatment . After thiopental anesthesia (25 mg/kg IV), animals were instrumented to measure various cardiovascular parameters . Endotoxic shock was induced by injecting Escherichia coli (0111:B4) endotoxin (1 mg/kg IV) . Benoxaprofen (10 mg/kg IV; N = 13), ibuprofen (12.5 mg/kg; N = 6), or saline (N = 12) was injected 60 minutes after endotoxin administration . During the treatment period, both benoxaprofen and ibuprofen increased mean arterial pressure, heart rate, and vascular resistance to the same degree over the control animals . Benoxaprofen did increase dP/dtmax while ibuprofen did not . Twenty-four-hour survival was 0% for the control animals (N = 12), 0% for the ibuprofen group (N = 6), and 61.5% for the benoxaprofen group (N = 13) . In an additional set of experiments, benoxaprofen (N = 8) was given 120 minutes after endotoxin administration and demonstrated similar improvements in hemodynamics and survival . These data demonstrate that benoxaprofen could improve survival in an otherwise lethal endotoxic model and suggest that the products of the lipoxygenase pathway may contribute to the lethality of an LD100 endotoxic shock model. Circ Shock, 1985, 15(1), 49 - 59 Dramatic changes in blood gases that are unrelated to arterial pH or cerebral oxygen delivery during endotoxin shock in conscious rats; Law WR et al.; In preliminary studies we demonstrated an effect of endotoxin on arterial blood gases that appeared to be related to the dose of endotoxin used and unrelated to changes in arterial pH . In the present study we tested the hypothesis that these changes in blood gases result from decreased oxygen delivery to central respiratory control areas . PO2 significantly rose from a pre-endotoxin value of 91.4 +/- 1.5 (mean +/- SEM) to 97.5 +/- 1.7, 104.0 +/- 0.8, and 108.4 +/- 0.9 at 10, 30, and 60 minutes, respectively, after administration of 6 mg/kg endotoxin and from 93.8 +/- 3.1 to 105.2 +/- 2.6, 118.7 +/- 1.4, and 121.0 +/- 2.8, respectively, after administration of 10 mg/kg endotoxin . PCO2 fell significantly from a pre-endotoxin value of 38.3 +/- 1.2 to 28.6 +/- 0.6 and 24.5 +/- 1.9 at 30 and 60 minutes post-endotoxin, respectively, in 6-mg/kg-treated rats, and from 40.5 +/- 2.1 to 30.7 +/- 4.5, 20.1 +/- 3.9, and 19.3 +/- 1.0, respectively, at 10, 30, and 60 minutes post-10 mg/kg endotoxin . The only significant change (decrease) in pH occurred at 60 minutes after 10 mg/kg treatment . In 10-mg/kg-treated rats, serum lactate rose significantly over time, while HCO-3 decreased . Heart rate was increased significantly (472 +/- 9.6) from a pre-10 mg/kg endotoxin value of 373 +/- 11.8 by 10 minutes post-endotoxin and remained elevated throughout the experiment . Cerebral medullary/pontine blood flow, mean arterial blood pressure, and respiratory rate were not significantly altered by endotoxin administration . Hemoglobin concentration and arterial oxygen content were significantly increased after 10 mg/kg endotoxin . These findings indicate that decreased oxygen delivery to central respiratory control areas is not a cause of the observed dramatic changes in blood gases. Am J Vet Res, 1985 Jan, 46(1), 175 - 80 Effect of Escherichia coli endotoxin and thyrotropin-releasing hormone on prolactin in lactating sows; Smith BB et al.; Primiparous gilts were given subcutaneous injections of saline solution or 8 mg of Escherichia coli endotoxin (055:B5 strain) in saline solution on postpartum days (PPD) 2 and/or 6 and saline solution at the same site on PPD 1, 3, 5, and 7 at 1000 hours . On PPD 1 to 3 and on PPD 5 to 7, pigs were given 100 micrograms of thyrotropin-releasing hormone (TRH) IV at 1300 hours to evaluate TRH-induced prolactin (PRL) release . Blood samples were analyzed for PRL, cortisol, triiodothyronine (T3), and tetraiodothyronine (T4) concentrations . Rectal temperatures were monitored at hourly intervals between 0800 and 1500 hours on PPD 2 and 6 . The PRL declined after endotoxin administration on PPD 2, but a similar decline was not seen after saline solution administration on PPD 1, 2, or 3 . The PRL concentrations remained unchanged on PPD 5, 6, and 7 in gilts exposed to endotoxin for the 1st or 2nd time on PPD 6 and to saline solution on PPD 5 and 7 . The TRH injection caused increases in PRL in all animals, but the PRL increase after TRH injection was significantly lower (P less than 0.05) in gilts treated with endotoxin on PPD 2 . Cortisol concentrations increased after endotoxin exposure on PPD 2 and 6 . Rectal temperatures increased after endotoxin exposure on PPD 2 and 6 with peak temperatures of 41.8 C and 41.6 C seen 4 and 3 hours, respectively, after endotoxin injection . The T3 and T4 response, used as an indicator of TRH perfusion of the adenohypophysis, was unchanged after endotoxin or saline solution administration.(ABSTRACT TRUNCATED AT 250 WORDS) Proc Natl Acad Sci U S A, 1985 Jan, 82(2), 272 - 6 Phosphorylation of ribosomal protein S6 on serine after microinjection of the Abelson murine leukemia virus tyrosine-specific protein kinase into Xenopus oocytes; Maller JL et al.; Phosphorylation of ribosomal protein S6 in NIH 3T3 fibroblasts is dependent on the presence of serum, but after transformation of these cells by Abelson murine leukemia virus (Ab-MuLV), S6 remained highly phosphorylated on serine residues either in the absence or the presence of serum . To investigate whether S6 phosphorylation in this system was a consequence of the action of the Ab-MuLV tyrosine-specific protein kinase, purified Ab-MuLV kinase made in Escherichia coli was microinjected into Xenopus oocytes and was observed to cause a 7- to 15-fold increase in the phosphorylation of S6 on serine residues . Two-dimensional phosphopeptide maps of S6 phosphorylated in Ab-MuLV-transformed NIH cells in the absence of serum were identical to those of S6 isolated from normal cells grown in the presence of serum . In addition, S6 from oocytes injected with Ab-MuLV kinase yielded an S6 phosphopeptide map indistinguishable from that of serum-stimulated NIH 3T3 cells, whereas S6 from control oocytes lacked several phosphopeptides . Ab-MuLV kinase did not phosphorylate S6 directly in vitro, and microinjection of a mutant Ab-MuLV protein lacking kinase activity had no effect . These results indicate that the Ab-MuLV kinase interacts with a cellular pathway to enhance S6 phosphorylation by directly or indirectly activating an S6 protein kinase and/or inactivating an S6 protein phosphatase. J Bacteriol, 1985 Jan, 161(1), 461 - 2 Evidence for an internal promoter in the Escherichia coli threonine operon; Saint Girons I et al.; We constructed plasmids carrying the two first genes of the threonine operon from which the major promoter was deleted in vitro by digestion with BAL 31 nuclease . These plasmids continued to express the second gene (thrB) of the operon as judged by their ability to complement a threonine auxotroph . These data indicate that, in addition to the major promoter thrP, there was an internal promoter, thrBp, which could be used for the transcription of the thrB, the second gene of the operon . Additional evidence was given by subcloning a 230-base-pair segment of the operon in a plasmid suitable for detection of translation initiation signals and promoters . The thrBp promoter was thus shown to lie within a 61-base-pair fragment at the 3' end of the first gene, thrA, of the threonine operon. J Bacteriol, 1985 Jan, 161(1), 450 - 3 Mapping of a mutation affecting regulation of iron uptake systems in Escherichia coli K-12; Bagg A et al.; The site of a mutation resulting in constitutive derepression of iron uptake systems has been localized at 15.7 min on the genetic map of Escherichia coli K-12. J Bacteriol, 1985 Jan, 161(1), 272 - 6 A mutation in Escherichia coli K-12 results in a requirement for thiamine and a decrease in L-serine deaminase activity; Newman EB et al.; Mutants of Escherichia coli K-12 deficient in L-serine deaminase (L-SD) activity have been isolated . These strains required thiamine and grew normally when it was provided . The decrease in L-SD activity caused no obvious metabolic deficiency . A study of revertants and transductants showed that a single mutation was responsible for the thiamine requirement and for the decrease in L-SD activity. J Bacteriol, 1985 Jan, 161(1), 147 - 52 Posttranscriptional regulation of the inducible nonenzymatic chloramphenicol resistance determinant of IncP plasmid R26; Dorman CJ et al.; The inducible nonenzymatic chloramphenicol resistance (Cmr) determinant of the IncP plasmid R26 was cloned on a 1,900-base-pair restriction endonuclease HindIII fragment . Transposon Tn5 mutagenesis revealed that at least 1,400 base pairs is required for expression of Cmr . There was no increase in the level of Cmr when the copy number of the determinant was raised by cloning in pBR322 or pUB5572 . Expression of Cmr by cells carrying a lower-copy-number pUB5572cml+ plasmid was inducible and thus indistinguishable from those with R26 itself . However, pBR322cml+-carrying cells expressed Cmr constitutively, possibly due to the activity of vector promoters or an elevated copy number . Transcriptional and translational cml-lac fusions were constructed . The operon (transcriptional) cml-lac fusion carried by the low-copy-number plasmid pUB5572 caused a low level of constitutive beta-galactosidase activity, which could not be elevated by induction with chloramphenicol and was not affected by a coresident R26cml+ element . In contrast, the gene (translational) cml-lac fusion expressed low-level beta-galactosidase activity, which was elevated fivefold by prior exposure to chloramphenicol . We conclude that the regulation of Cmr occurs posttranscriptionally. J Bacteriol, 1985 Jan, 161(1), 128 - 32 Internal promoter in the ilvGEDA transcription unit of Escherichia coli K-12; Calhoun DH et al.; Segments of the ilvGEDA transcription unit have been cloned into the promoter tester plasmid pMC81 . This vector contains cloning sites situated upstream of the lacZ gene coding for beta-galactosidase . Using this method we have quantitatively evaluated in vivo (i) the activity of previously described promoter, pG, preceding ilvG; (ii) the relative activity of pE promoter, previously postulated to be located between ilvG and ilvE; and (iii) the effect of the frameshift site present in the wild-type ilvG gene by comparison with mutant derivatives lacking this frameshift site . Isogenic derivatives of strain MC1000 were constructed by transduction with phage P1 grown on rho-120, delta(ilvGEDA), delta(ilvED), and ilvA538 hosts . The potential effects of these alleles that were previously postulated to affect ilvGEDA expression were assessed in vivo by monitoring beta-galactosidase production directed by ilv DNA fragments . Cloned ilv segments were also tested for activity in vitro with a DNA-directed coupled transcription and translation system . The production in vitro of ilv-directed ilv gene expression and beta-galactosidase expression with ara-ilv-lac fusions paralleled the in vivo activity. J Bacteriol, 1985 Jan, 161(1), 105 - 12 Aberrant regulation of methylesterase activity in cheD chemotaxis mutants of Escherichia coli; Kehry MR et al.; The adaptation process in several cheD chemotaxis mutants, which carry defects in tsr, the serine transducer gene, was examined . cheD mutants are smooth swimming and generally nonchemotactic; the defect is dominant to the wild-type tsr gene (J . S . Parkinson, J . Bacteriol . 142:953-961, 1980) . All classes of methyl-accepting chemotaxis proteins synthesized in unstimulated cheD strains are overmethylated relative to the wild type . We found that the steady-state rate of demethylation in cheD mutants was low; this may explain their overmethylated phenotype . In addition, all cheD mutants showed diminished responsiveness of methylesterase activity to attractant and repellent stimuli transduced by either the Tsr or Tar protein, and they did not adapt . These results suggest that the dominant nature of the cheD mutations is manifested as a general defect in the regulation of demethylation . Some of these altered properties of methylesterase activity in cheD mutants were exhibited in wild-type cells that were treated with saturating concentrations of serine . The mutant Tsr protein thus seems to be locked into a signaling mode that suppresses tumbling and inhibits methylesterase activity in a global fashion . We found that the Tar and mutant Tsr proteins synthesized in cheD strains were methylated and deamidated at the correct sites and that the mutations were not located in the methylated peptides . Thus, the signaling properties of the transducers may be controlled at sites distinct from the methyl-accepting sites. Am J Clin Nutr, 1985 Jan, 41(1), 61 - 5 Hyperalimentation-associated jaundice: an example of a serum factor inducing cholestasis in rats; Latham PS et al.; A patient receiving total parenteral nutrition (TPN) at home following emergency resection of the small intestine was studied over a two year interval . Cholestatic jaundice developed after 6 months . A factor in serum was found to produce cholestatic changes in the bile flow of rats on intravenous infusion . Normal human serum and saline infusion did not produce this cholestasis . Endotoxin infusion in the rat produced a similar impairment in bile flow . The hypothesis was proposed that endotoxin might be an occult factor contributing to cholestasis in this case . An antiserum prepared to an endotoxin isolated from a sequestered E . coli infection in this patient, ameliorated the cholestatic effects of the patients' serum in rats . The possible role of endotoxin in the cholestasis of the TPN-induced jaundice in this patient is presented and discussed. J Enzyme Inhib, 1985, 1(1), 67 - 75 Inhibition of adenosine deaminase from several sources by deaza derivatives of adenosine and EHNA; Lupidi G et al.; Deaza analogues of adenosine and EHNA were tested as inhibitors of the enzyme adenosine deaminase (ADA) obtained from several sources including human erythrocytes, calf intestine, Saccaromices cerevisiae, Escherichia coli and Takadiastase . Ki values of the inhibitors suggest differences among the enzymes both at purine and erythro-nonyl binding site . Among the ribofuranosyl derivatives, 1-deazaadenosine is the best inhibitor, its Ki ranging between 3.5 x 10(-7) and 4 x 10(-5) M for ADA from erythrocytes and Takadiastase respectively . Only ADA from erythrocytes and calf intestine bind EHNA and some of deazaEHNA analogues; 3-deazaEHNA behaves very similarly to EHNA both in affinity and slow binding mechanism, whereas 1-deazaEHNA, though less potent, is a good inhibitor. Free Radic Res Commun, 1985, 1(2), 79 - 88 Transition metals potentiate paraquat toxicity; Kohen R et al.; The involvement of transition metal ions in paraquat toxicity was studied in bacterial model system . We show that the addition of micromolar, or lower, concentrations of copper dramatically enhanced the rate of bacterial inactivation . In contrast, the addition of chelating agents totally eliminated the killing of E . coli . No inactivation was observed under anaerobic exposure to paraquat, both in the absence and presence of copper . However, in the presence of copper, the anaerobic addition of hydrogen peroxide resulted in complete restoration of inactivation as under aerobiosis . Paraquat either produces superoxide ions or directly reduces bound copper ions in a catalytic mode . The reduced cuprous complexes react with hydrogen peroxide to locally form hydroxyl radicals (OH.) which are probably responsible for the deleterious effects . This study indicates the involvement of a site-specific metal-mediated Haber-Weiss mechanism in paraquat toxicity . It is in agreement with earlier observations that copper unusually enhance biological damage induced by either superoxide or ascorbate. Curr Genet, 1985, 9(8), 653 - 60 Efficient expression of the Escherichia coli leuB gene in yeast; McNeil JB et al.; Efficient expression of the Escherichia coli leuB (beta-isopropylmalate dehydrogenase) gene occurred in yeast after in vitro DNase digestion and religation of plasmid bound leuB and the yeast HIS3 DNA which placed the 5' end of the yeast HIS3 gene immediately adjacent to the coding region of the E . coli leuB gene . Two structurally distinct classes of gene fusions were constructed, each involved portions of the yeast HIS3 gene which contributed DNA sequences responsible for leuB expression in yeast . The first class involved fusion of the HIS3 coding region to bacterial DNA resulting in the production of a fusion protein with beta-isopropylmalate dehydrogenase activity . The second class consisted of bacterial DNA, including the leuB coding region, fused to the HIS3 promotor region with the absence of any portion of the HIS3 coding region . In both constructions the HIS3 promotor region is required for transcription, however, translation of the class two fusion is initiated at a bacterial DNA coded AUG, and the 5' end of the mRNA coded by the leuB gene mapped predominantly at bacterial DNA sequences . The DNA sequence responsible for the 5' end of the HIS3 mRNAs remain in the class two gene fusions but this did not preclude the initiation of transcription at bacterial DNA sequences . The pattern of mRNA initiation at bacterial DNA suggests that DNA sequences at, or adjacent to, the site of transcription initiation are involved in the determination of the sites of initiation, and perhaps the frequency at which initiation occurs. Curr Genet, 1985, 9(4), 305 - 11 Cloning and characterization of the three enzyme structural genes QUTB, QUTC and QUTE from the quinic acid utilization gene cluster in Aspergillus nidulans; Hawkins AR et al.; Heterologous DNA probes from the quinic acid gene cluster (QA) in Neurospora crassa (Schweizer 1981) have been used to isolate the corresponding gene cluster (QUT) from Aspergillus nidulans cloned in a phage lambda vector . N . crassa probes for each of the three enzyme structural genes in the cluster have been used to identify the corresponding genes within the A . nidulans cloned DNA . The three genes are in the same relative sequence {dehydrogenase (1), QA-3 = QUTB; dehydratase (3), QA-4 = QUTC; dehydroquinase (2), QA-2 = QUTE} though contained within a 3.4 kb DNA sequence in Aspergillus compared to a 5.4 kb sequence in Neurospora . The A . nidulans dehydroquinase (2) gene QUTE has been shown to complement an auxotrophic mutant aroD6 of Escherichia coli lacking biosynthetic dehydroquinase when tested for growth at 30 degrees C . A mutant of A . nidulans lacking catabolic dehydroquinase (2) and designated qutE208 has been isolated and shown to be tightly linked to the gene cluster, which maps between the ornB and fwA loci in linkage group VIII. Mol Biol Evol, 1985 Jan, 2(1), 1 - 12 The tetracycline repressor of pSC101; Brow MA et al.; We have determined the nucleotide sequence of the gene for the repressor of the pSC101 tetracycline resistance element (tetR) . The repressor gene is transcribed divergently from the gene that encodes the resistance protein and encodes a putative protein of 219 amino acids . The genetic organizations of the three major types of bacterial tetracycline resistance elements thus appear to be equivalent, even though they do not show substantial nucleic acid similarity . The pSC101 repressor protein is 80% identical with the Tn 1721 repressor over its N-terminal 150 residues, whereas the C-termini of the two species are only 35% identical . Examination of the nucleic acid sequences of the regions between the two divergent promoters suggests a model in which two dimers of the tetracycline repressor molecule interact at two adjacent dyad repeats . The dimers may interact with each other, thus strengthening their grip on the operator, and affect transcription of the repressor gene . Comparison of the tetracycline (Tet) repressor with the lambda repressor suggests that the N-terminal region of the Tet repressor forms a helix-turn-helix structure and interacts with DNA in the major groove . The region of the Tet repressor implicated in DNA binding shows significant sequence similarity to a region of histone H4, suggesting that the histone may bind to DNA by means of a similar structural motif. Pharmacol Ther, 1985, 31(1-2), 141 - 51 Quantitation of DNA repair capacities of human tumor cells by estimation of transfer of DNA adducts to repair proteins; Yarosh DB; The repair of O6-methylguanine produced in DNA by alkylating agents is accomplished by a unique lesion reversal mechanism which recognizes the methyl group and transfers it to itself in a suicide reaction . Much of what we know about the importance of O6-methylguanine-DNA methyltransferase repair in human cells comes from the study of Mer- tumor cell strains which are deficient in transferase activity . The human transferase has a preference for repair of methyl groups, but will also act on other substrates . Assays for transferase activity detect either the loss of O6-methylguanine from DNA or the appearance of methylated protein . A new assay detects the recovery of a restriction site in a synthetic polymer following demethylation . Inhibition of transferase activity can be produced in cells by several methods. Drugs Exp Clin Res, 1985, 11(11), 747 - 54 Dissociated effect of amphotericin B and desoxycholate on phagocytosis of Escherichia coli by human polymorphonuclear neutrophils; Lingaas E et al.; The influence of commercial amphotericin B-desoxycholate (Fungizone) and desoxycholate alone on phagocytosis of Escherichia coli by human polymorphonuclear neutrophils in vitro was studied . A dissociated effect of amphotericin B and desoxycholate was observed . Amphotericin B was shown to stimulate the ingestion of Escherichia coli through an effect on the bacteria as well as on the neutrophils . Desoxycholate inhibited phagocytosis through an effect on the neutrophils and also, at low concentrations (0.08 microgram/ml), through an effect on the bacteria . On the other hand, pretreatment of Escherichia coli with high concentrations (8.2 micrograms/ml) of desoxycholate rendered it more susceptible to phagocytosis . The elimination of bacterial breakdown products from the neutrophils after ingestion of Escherichia coli was also inhibited by desoxycholate and stimulated by amphotericin B . Most of these effects disappeared in the presence of 10% serum . An alteration of bacterial hydrophobicity could only partly explain the effect of amphotericin B. Bull Soc Pathol Exot Filiales, 1985, 78(5 Pt 2), 921 - 9 {Escherichia coli diarrhea of children and adults at the Brazzaville General Hospital}; Yala F et al.; The high number of the strains of Escherichia coli (E . coli) isolated from faeces, demonstrated that this bacteria takes the first place in diarrhoea . These isolations had the same frequency all the year long . In infants, the enteropathogenic E . coli (E . P . E . C.) (28.57%) are still frequent contrary to developed countries . The E . coli with hemagglutination phenomenon (colonisation factors) but without toxin detected were also responsible (mortality 6%) . The E . coli without toxin and not belonging to E . P . E . C . group were also frequent (71.42%) . In adults, only the enteroinvasive E . coli (E . I . E . C.) (16.6%) and the E . coli with hemagglutination but without toxin detected (16.6%) were observed . This situation is due to bad hygienic conditions among the people and the tropical climate. Physiol Chem Phys Med NMR, 1985, 17(4), 347 - 50 Distinct effects of pyridoxal phosphate on NAD- and NADP- linked malic enzymes of Escherichia coli; Tokushige M et al.; NADP-linked malic enzyme from Escherichia coli W was inactivated by pyridoxal 5'-phosphate (PLP) following pseudo-first order kinetics . The inactivation was, however, reversed upon addition of an aminothiol, such as penicillamine and cysteamine, whereas the activity was not restored, when the PLP-inactivated enzyme was treated with NaBH4 prior to the addition of aminothiol . The inactivating effect was specific to PLP and no other structural analogs of PLP tested inactivated the enzyme, except that pyridoxal exhibited a similar effect, though to a lesser extent . In contrast, NAD-linked malic enzyme from the same micro-organism was insensitive to PLP, even in the presence of 0.8 M guanidine hydrochloride. J Cell Sci Suppl, 1985, 3, 11 - 7 In vivo aspects of urogastrone-epidermal growth factor; Gregory H; Recent evidence indicates that human urogastrone-epidermal growth factor originates in submandibular and Brunner's glands and that serum levels are low (less than 1 ng ml-1) . It occurs in many secreted fluids to a much greater extent and many tissues are thus exposed to concentrations greater than 100 ng ml-1 . Rapid actions in vivo of URO-EGF include the ability to inhibit gastric acid secretion at low doses (250 ng kg h-1 in humans) and to provide cytoprotective effects against ulcerogenic agents (250 ng kg h-1 in cats) . More prolonged exposure of tissues shows increases in parameters related to wound healing, beneficial effects upon ulceration and also the ability to accelerate crypt cell production rate along the gastrointestinal tract . Synthetic material has been prepared with an identical structure to the natural URO-EGF thus enabling detailed studies of the biological effects to be pursued. Aust J Biol Sci, 1985, 38(4), 383 - 92 Studies on the accumulation of putrescine and spermidine in Escherichia coli; Smigielski AJ et al.; The rate of accumulation of the polyamines spermidine and putrescine by E . coli depended on growth rate . Spermidine accumulation was faster in chemostat cultures with high dilution rates than in those with low dilution rates and was slower in bacteria that had been grown for several generations with either putrescine or spermidine, suggesting that the spermidine-uptake system was repressed by exogenous polyamines . The uptake of spermidine required metabolic energy . Thus accumulation occurred in an energy-starved unc strain only upon addition of glucose (or D-lactate to a smaller extent) . With glucose present accumulation occurred in an unc, frd strain under anaerobic conditions, suggesting that ATP drives uptake . However, accumulation was generally sensitive to carbonylcyanide m-chlorophenylhydrazone (CCCP), indicating that the proton motive force was involved in uptake . Unlike spermidine, putrescine accumulation was faster in slow-growing than in fast-growing cultures . This may have been due to greater efflux of putrescine at faster growth rates . Accumulation of putrescine was faster following prolonged growth with either putrescine or spermidine, suggesting induction of the putrescine-uptake system by exogenous polyamines . Like spermidine accumulation, putrescine accumulation required metabolic energy . Accumulation was insensitive to CCCP and occurred only when glucose was added to energy-starved unc bacteria, suggesting that high-energy bonds may drive the uptake of putrescine. Adv Biophys, 1985, 20, 109 - 35 Ions as regulators of protein-nucleic acid interactions in vitro and in vivo; Record MT Jr et al.; The key feature of the kinetics and equilibria of both specific and non-specific noncovalent interactions of proteins with nucleic acids is their sensitivity to the details of the ionic environment . Investigation of the effects of ion concentrations provides detailed and otherwise unobtainable information about the thermodynamics and mechanisms of these interactions . We discuss the molecular and thermodynamic basis of the contribution to these ion effects from electrolyte-nucleic acid interactions, and demonstrate that a simple ion exchange formalism, involving the stoichiometric participation of individual ions, is the appropriate basis for interpreting these profound effects at a thermodynamic level . Since the in vivo ionic environment is both complex and variable, we propose that variations in intracellular concentrations of individual ions play both global and specific roles in the control of the protein-nucleic acid interactions responsible for nucleoprotein structure and gene expression. Arch Immunol Ther Exp (Warsz), 1985, 33(6), 755 - 61 Migration of isolated rabbit lymphocytes in the course of pharmacological inhibition of pyrogenic fever; Debowy J et al.; The studies concerned in vitro migration of peripheral blood lymphocytes of rabbits given intravenously one dose of E . coli lipopolysaccharide (LPS) and antipyretic doses of acetylsalicylic acid (ASA), indomethacin (IND) or mefenamic acid (MEFA) . In normothermic animals, ASA appeared to inhibit in vitro the spontaneous migration of lymphocytes . Contrary to ASA, MEFA and IND did not produce any significant changes in lymphocytes migration . Four hours after pyrogen injection migration of lymphocytes was slightly enhanced and after 24 h it was significantly inhibited . All non-steroid anti-inflammatory drugs examined counteracted this effect. Arch Immunol Ther Exp (Warsz), 1985, 33(6), 727 - 34 Chlormethine in small doses as immunostimulator--LPS synergism; Garbulinski T et al.; Normothermic rabbits and rabbits with LPS induced fever were treated with chlormethine (Nitrogranulogen, Ntg) in the doses of 1 microgram/kg and 10 micrograms/kg . The blood was collected 4, 24, 48 hrs and 4, 7, 10 days after Ntg injection . Following indices of immunity were studied: T and B cells number, number of IgM producing cells after immunization with SRBC, serum IgG level, killing activity of neutrophils and number of phagocytized bacteria . It was observed that both doses of Ntg injected intravenously to normothermic rabbits, significantly increased the number of T and B lymphocytes and of IgM producing lymphocytes a well as the level of IgG in the serum, number of phagocytized bacteria and killing activity of neutrophils . Ntg in combination with LPS shortened the period of fever, and through the synergistic effect, significantly increased T lymphocytes number in the blood, IgG level in the serum, number of phagocytized bacteria and killing activity of neutrophils. Trans R Soc Trop Med Hyg, 1985, 79(6), 840 - 2 Recovery of potential pathogens from feeding bottle contents and teats in Zaria, Nigeria; Cherian A et al.; Pathogens were recovered from the contents of 41 out of 50 feeding bottles and from 32 teats in a survey in Zaria, Nigeria . 39 bottle contents and 30 teats yielded enteric pathogens . Traditional weaning gruels were more contaminated than were commercial feeds . Koko bottles yielded more pathogens than Akamu bottles . Enteropathogenic Escherichia coli was the most common pathogen recovered, seen more in bottle contents than teats . Bottle hygiene was poor and cleaning methods and feeding practices were not satisfactory . Lack of facilities in the home prevented better hygiene . Prolonged pre-cooking preparation, storage of gruels in bulk for the whole day in thermos flasks or enamel bowls, and inadequate hygiene in the preparation of commercial feeds resulted in the large recovery of pathogens . Alternate feeding methods were suggested and the need for the practice of good hygiene by all who are involved in the preparation of infant feeds was emphasized. Microbios, 1985, 44(177), 7 - 20 Effect of anaesthetics and dichlorodifluoromethane on the viability of the cells of Escherichia coli and the activities of some of its enzymes; Laverty DM et al.; Three anaesthetics (halothane, CF3CHClBr; Ethrane, F2 HCOF2CCHClF; cyclopropane) and one other halogenated, short-chain hydrocarbon (F-12, Cl2F2C) were tested under various conditions to determine their effects on the viability of cells of Escherichia coli and the activities of some of its enzymes . When any of the test chemicals were applied for 60 min at concentrations slightly in excess of saturation, the number of surviving cells decreased substantially, with halothane being the most biocidal of the four chemicals and F-12 the least . Three enzymes (malate dehydrogenase, MD; NADH dehydrogenase; glyceraldehyde-3-phosphate dehydrogenase, GPD) were tested for activity after treatment of E . coli with the test chemicals . In all instances, GPD was least resistant to inactivation and MD was most resistant . Halothane was most inhibitory followed in order by Ethrane, cyclopropane and F-12 . Treatment of E . coli with halothane for 60 min at 23 degrees C and a concentration slightly in excess of saturation, resulted in nearly complete inhibition of all three enzymes. Microbios, 1985, 44(177), 45 - 9 Kinetics of dark repair inhibition in ultraviolet damaged DNA by substituted quinolines; Sideropoulos AS et al.; The effects of chloroquine on the kinetics of the dark repair process were investigated by employing a cellular system . Lineweaver-Burke plots and Dixon plots of chloroquine inhibition, respectively, showed that there was an increase in slope with increasing concentration of inhibitor which followed an enzyme-like pattern . These results are consistent with a model for excision-repair in which chloroquine may block the excision repair pathway. Gene, 1985, 40(2-3), 191 - 201 Characterization of Streptomyces promoter sequences using the Escherichia coli galactokinase gene; Brawner ME et al.; A gene fusion system that uses the Escherichia coli galK gene has been developed to characterize Streptomyces transcriptional regulatory sequences . The system consists of galK-deficient Streptomyces lividans mutants and plasmids containing the E . coli galK gene with its natural ribosome-binding site and sites upstream of galK for insertion of transcription signals . Expression of the E . coli galK gene in S . lividans can be quantitated by either an enzymatic or immunoblot assay or detected by genetic complementation of an S . lividans galK- mutant . The utility of the plasmid to select, detect and assess promoter function was examined using the S . lividans XP55 and S . fradiae aph gene promoters . The potential use of the galK fusion system to isolate and characterize Streptomyces transcription signals is discussed. J Emerg Med, 1985, 3(1), 1 - 9 Acute infectious diarrheal disease in children; Barkin RM; The management of acute diarrheal disease in children must consider potential etiologic agents and their common presentation . The workup and assessment should be tailored to the clinical condition of the patient and the most likely pathogen . Management must primarily focus on fluid therapy and dietary manipulation . Antibiotics have a very restricted role as do antidiarrheal agents. Acta Chir Scand Suppl, 1985, 526, 94 - 103 High-dose methylprednisolone in a porcine model of ARDS induced by endotoxemia; Modig J et al.; Using a continuous i.v . infusion of E . coli endotoxin in spontaneously breathing pigs under ketamine anesthesia we have developed a lung injury model which closely mimics the pathophysiological and morphological changes of early ARDS induced by sepsis in man . Pretreatment with high doses of methylprednisolone largely prevented the pulmonary, cardiovascular and morphological features induced by the endotoxin . Methylprednisolone treatment initiated 2 h after starting the endotoxin abolished further derangements in pulmonary and cardiovascular functions and there was a restoration towards normal values . Both pretreatment and delayed treatment with methylprednisolone improved survival . Although one should be extremely cautious in extrapolating these data to the more complex clinical situation, the implications are that high doses of methylprednisolone, given early in the course of sepsis in man, may help to prevent both the pulmonary and cardiovascular derangements of this disease. Acta Chir Scand Suppl, 1985, 526, 124 - 8 High doses of corticosteroids in the treatment of septic shock; Hellman A et al.; High doses of corticosteroids are reported to be beneficial in the treatment of septic shock in many animal species, e.g . dog, rat and rabbit . Recent findings in baboons subjected to E . coli shock indicate that early treatment with a combination of antibiotics and steroids strongly enhance survival rate . In clinical studies the protective effects of steroids are more ambiguous, however . In part this may be explained by variations in the amount of steroids used or by the fact that in some studies the steroid is administered late in shock . The dose recommended, 30 mg/kg bw of methylprednisolone or an equivalent amount of another glucocorticoid given once or twice, is based on animal as well as clinical documentation. Acta Chir Scand, 1985, 151(6), 501 - 8 Positive effects of prophylactic ventilator treatment on gas exchange and extravascular lung water in a porcine model of adult respiratory distress syndrome induced by endotoxaemia; Borg T et al.; The influence of prophylactic ventilator treatment was evaluated in a porcine model of early adult respiratory distress syndrome (ARDS) induced by endotoxaemia . Sixteen animals, controls, under continuous i.v . ketamine anaesthesia were either mechanically ventilated using intermittent positive pressure ventilation (IPPV; n = 6) with air or breathed air spontaneously (n = 10) . Twenty animals under continuous i.v . ketamine anaesthesia and spontaneously breathing air were infused i.v . with E . coli endotoxin (10 micrograms X kg-1 X h-1) over 6 h . Fifteen animals under continuous i.v . ketamine anaesthesia were given IPPV with air and were infused i.v . with E . coli endotoxin in the same dosage regimen . In the controls, cardiac output decreased slightly . Otherwise there were no changes in pulmonary gas exchange, pulmonary haemodynamics or extravascular lung water . In spontaneously breathing and IPPV animals given endotoxin there was a profound deterioration in pulmonary gas exchange, a marked rise in pulmonary vascular resistance and a moderate increase in extravascular lung water . Animals given IPPV showed a significantly less pronounced impairment in pulmonary gas exchange and a significantly smaller increase in extravascular lung water than in animals breathing spontaneously, whereas the changes in pulmonary haemodynamics were fairly similar in both groups . Animals with IPPV also had an improved survival rate . The beneficial effects of mechanical ventilation on pulmonary gas exchange are not due to changes in extravascular lung water, but are caused by its influence in counteracting terminal airway and alveolar closure . These results indicate that mechanical ventilation, when instituted early in the course of human ARDS induced by septicaemia, might be of potential value in the prevention of severe pulmonary failure and death. Ultrastruct Pathol, 1985, 9(3-4), 215 - 24 Electron microscopic analysis of lymphocyte nuclei in non-Hodgkin's lymphoma; Dardick I; Ultrastructural studies of normal and neoplastic lymphocytes are presented that qualitatively and quantitatively assess the central cell organelle currently used by surgical pathologists in the classification of non-Hodgkin's lymphoma, the nucleus . Events occurring during normal lymphocyte transformation can be used to appreciate essential mechanisms involved in producing the appearance of the nucleus as seen by microscopy . Quantitation of nuclear subcompartments by morphometric image analysis reveals that determination of nuclear size is primarily due to the ribonucleoprotein materials distributed between condensed chromatin masses, the interchromatinic (euchromatin or nuclear matrix) region . Furthermore, such investigations show that amounts and distribution of condensed chromatin in lymphocyte nuclei cannot be adequately assessed from routine histologic sections . Ultrastructural morphometric analysis of representative cases of the principal subtypes of NHL indicates that the atypical morphologic appearance of neoplastic lymphocytes results from a complex interplay between total amounts of condensed chromatin in nuclei and the size of individual aggregates of condensed chromatin, one or both of which may be abnormal in NHL . Abnormalities of interchromatinic materials are also likely involved in ordering the gross appearance of the nucleus . Understanding of both the dynamic capabilities of the nucleus, and the organization of and interplay between the various subcompartments of this organelle will be helpful in improving the classification of NHL by surgical pathologists. Nucleic Acids Symp Ser, 1985, (16), 261 - 3 RNA polymerase: direct evidence for two active sites involved in transcription; Dennis D; Photoaffinity reagents (3'-azido analogues of 5' ATP and 5' GTP) were used to label two different sites at the catalytic surface of the beta subunit of the E . coli DNA dependent RNA polymerase . These sites are used alternately and successively during consecutive phosphodiester bond formation . This result is consistent with our model of rotational translocation for transcription. Nucleic Acids Symp Ser, 1985, (16), 237 - 9 Ambiguous incorporation of N4-aminodeoxycytidine 5'-triphosphate to DNA synthesized in vitro; Negishi K et al.; Molecular mechanism of the mutation induced by N4-aminocytidine was studied . The specificity of in vitro incorporation of N4-aminodeoxycytidine 5'-triphophate catalyzed by E . coli DNA polymerase large fragment was analyzed . The results have shown that this cytosine analog can be efficiently incorporated as a substitute of cytosine, and that it can also be incorporated with a low efficiency as a substitute of thymine . We have also shown that the N4-aminocytosine incorporated opposite adenine can be excised as its monophosphate at a high frequency . The N4-aminocytosine residues in the polynucleotide templates can be read by the enzyme as efficiently as cytosines, and guanines were incorporated opposite them. Mol Gen Genet, 1985, 201(3), 537 - 42 The sfiA11 mutation prevents filamentation in a response to cell wall damage only in a recA+ genetic background; Cegielska A et al.; N-alpha-palmitoyl-L-lysyl-L-lysine dihydrochloride ethyl ester (PLL) at sublethal doses causes filamentous growth of E . coli strains except sfiA mutants, which divide normally in its presence . PLL does not elicit the SOS responses as judged by lambda prophage induction, an increase of RecA protein synthesis or induction of the sfiA operon in a sfiA::lacZ fusion strain . Thus, it appears that filamentation caused by PLL is not an SOS function and might be the result of membrane damage by PLL, which is an amphipathic compound and at higher doses causes cell lysis . This indicates that basal levels of the sfiA gene product are sufficient to inhibit cell division in the presence of PLL . We have found further that the phenotype of the sfiA mutation in the presence of PLL requires a recA+ genetic background and does not occur in E . coli recA1 sfiA11, recA13 sfiA11, recA56 sfiA11 and recA441 sfiA11 . All these strains, but rec441 sfiA11, however, regain the ability of sfiA11 mutants to divide in the presence of PLL after transformation with the RecA overproducing-plasmid pXO2 . This supports the conclusion that the RecA protein positively affects sfiA11-mediated cell division in the presence of the cell membrane damaging compound, PLL . The basal level of the RecA protein in the recA+ sfiA11 strain is sufficient for this process . An increased level due to overproduction from the multicopy plasmid pXO2 exerts the same effect. Mol Gen Genet, 1985, 201(3), 525 - 8 Role of Escherichia coli RecBC enzyme in SOS induction; Chaudhury AM et al.; Induction of the SOS genes is required for efficient repair of damaged DNA in Escherichia coli . SOS induction by nalidixic acid or oxolinic acid, two inhibitors of DNA gyrase, requires the RecBC enzyme of E . coli . We report here that the nuclease activity of RecBC enzyme is not needed for SOS induction by these agents . We suggest that the unwinding activity of RecBC enzyme produces single-stranded DNA which activates the RecA protein to stimulate LexA repressor cleavage and SOS induction. Mol Gen Genet, 1985, 201(3), 433 - 6 Gene rpmF for ribosomal protein L32 and gene rimJ for a ribosomal protein acetylating enzyme are located near pyrC (23.4 min) in Escherichia coli; Janda I et al.; An Escherichia coli mutant harbouring altered ribosomal protein L32 has been isolated and genetically characterized . The mutation leading to this alteration (rpmF) and the temperature-sensitive mutation (ts-1517) present in the same strain were found to map near pyrC (23.4 min), being cotransducible not only with pyrC but also with fabD, flaT and purB in P1 phage mediated transductions . Furthermore, we found that the gene rimJ, which encodes an enzyme that acetylates the N-terminal alanine of protein S5 and the temperature-sensitive mutation, ts-386, present in the rimJ mutant strain (Cumberlidge and Isono 1979) also mapped in this region . Thus, the order of genes is deduced to be: ts-386-pyrC-ts-1517-rimJ-flaT-fabD-rpmF-purB+ ++. Mol Gen Genet, 1985, 201(3), 387 - 92 Effect of a lexA41(Ts) mutation on DNA repair in recA(Def) derivatives of Escherichia coli K-12; Ganesan AK et al.; Derivatives of Escherichia coli K-12 carrying a deletion of the recA gene survive exposure to UV (254 nm) better if they also contain the lexA41 mutation which codes for a labile LexA protein . This effect of the lexA41 mutation is not observed in comparable strains carrying a uvr A6 mutation . Using two independent methods to detect pyrimidine dimers we found that UV irradiated RecA deficient cells removed dimers from their DNA more rapidly if they contained the lexA41 mutation than if they contained the wild-type lexA gene . Our results are consistent with the idea that a relatively high level of UvrABC incision nuclease resulting from inefficient repression of the corresponding genes by the labile LexA41 protein facilitates excision of pyrimidine dimers from the DNA of UV irradiated cells. Mol Gen Genet, 1985, 201(3), 379 - 86 Growth rate-dependent regulation of RNA polymerase synthesis in Escherichia coli; Ralling G et al.; The rate of synthesis of the beta and beta' subunits of RNA polymerase relative to the rate of synthesis of total protein was found to remain constant with increasing steady state growth rate . This is in contrast to the relative synthesis rates of ribosomal proteins which are known to increase with growth rate . Yet the ratio of the rate of transcription of the ribosomal protein (rplJL) and RNA polymerase (rpoBC) domains of the rplKAJLrpoBC gene cluster was found to be invariant . Fusions to lacZ were used to relate the rate of transcription of the rplKAJL genes to the rate of synthesis of total protein . No change was seen at growth rates above 0.8 doublings per hour . This indicates that the growth rate-dependent expression of these ribosomal proteins is regulated at the post-transcriptional level . However because both the relative rate of transcription of rpoBC and rate of synthesis of beta and beta' were found to remain invariant over this growth range it suggests the expression of these RNA polymerase subunits is regulated at the transcriptional level. Mol Gen Genet, 1985, 201(2), 186 - 91 Mechanism of sbcB-suppression of the recBC-deficiency in postreplication repair in UV-irradiated Escherichia coli K-12; Wang TC et al.; The mechanism by which an sbcB mutation suppresses the deficiency in postreplication repair shown by recB recC mutants of Escherichia coli was studied . The presence of an sbcB mutation in uvrA recB recC cells increased their resistance to UV radiation . This enhanced resistance was not due to a suppression of the minor deficiency in the repair of DNA daughter-strand gaps or to an inhibition of the production of DNA double-strand breaks in UV-irradiated uvrA recB recC cells; rather, the presence of an sbcB mutation enabled uvrA recB recC cells to carry out the repair of DNA double-strand breaks . In the uvrA recB recC sbcB background, a mutation at recF produced a huge sensitization to UV radiation, and it rendered cells deficient in the repair of both DNA daughter-strand gaps and DNA double-strand breaks . Thus, an additional sbcB mutation in uvrA recB recC cells restored their ability to perform the repair of DNA double-strand breaks, but the further addition of a recF mutation blocked this repair capacity. Mol Gen Genet, 1985, 201(2), 146 - 50 A new dispensable genetic locus of the terminus region involved in control of cell division in Escherichia coli; Bejar S et al.; Temperature-sensitive mutants defective in cell division were isolated after localised mutagenesis of the terminus region of the Escherichia coli chromosome . The defective gene in one of these mutants, dicA, was mapped at 34.9 min by linkage with manA and with three physically characterized Tn10 insertions . Temperature-sensitivity conferred by mutation dicA1 in a recA backround was suppressed by the presence of hybrid plasmids carrying the wild-type gene . In addition, the mutation was suppressed either by tranposon inactivation of a nearby gene, dicB, or by deletion of the entire dicA-dicB interval . These results define the dicA-dicB locus as a new dispensable genetic cluster involved in the control of cell division. Mol Gen Genet, 1985, 201(2), 141 - 5 Photoreactivation reverses ultraviolet radiation induced premutagenic lesions leading to frameshift mutations in Escherichia coli; Yamamoto K; The effect of photoreactivation of the ultraviolet radiation induced reversion of a trpE9777 frameshift mutation was studied in a uvr A6 derivative of Escherichia coli K12 . Two different photoreactivation treatments were used, one providing a single flash of photoreactivating light and another providing 10 min of light from fluorescent lamps . The reversion frequency of the trpE9777 frameshift mutation was strongly reduced when subsequently exposed to visible light . The dose modification factor (the ratio of equally effective doses), for cells challenged with single-flash photoreactivation, for survival and induction of reversion to Trp+ was 3.6 and 3.4, respectively . UV induction of RecA protein synthesis was not reversed by a single flash of photoreactivation . The dose modification factor for 10 min of fluorescent lamp photoreactivation for survival and for induction of reversion to Trp+ was 6.5 and 6.3, respectively . The dose modification factor for 10 min of photoreactivation for induction of RecA protein was 1.7-2.5 . Photoreactivation decreased the reversion of trpE9777 and increased survival to the same extent . We concluded that cyclobutyl pyrimidine dimers are the premutagenic lesions of UV mutagenesis of the trpE9777 allele in a uvr A6 background. Gene, 1985, 39(1), 85 - 7 Plasmid pFCE4: a new system of Escherichia coli expression-modification vectors; Lorenzetti R et al.; Two versatile expression-modification vectors were obtained by inserting the origin of replication (ori) of phage f1 into the expression vector pOTS . The resulting plasmids produce large amounts of coding or noncoding ssDNA (depending on ori orientation in pFCE4+ and pFCE4-) and excrete it into the medium as virus-like particles following infection with phage f1 . These features make them suitable for dideoxy chain termination sequencing, oligonucleotide directed mutagenesis and gene expression without further manipulations . The human IFN alpha-2 gene, lacking the codon for the first amino acid, cysteine, was efficiently expressed by these vectors. Gene, 1985, 39(1), 117 - 20 Expression of a synthetic human growth hormone gene in yeast; Tokunaga T et al.; A synthetic human growth hormone (hGH) gene was efficiently expressed under the control of the repressible acid phosphatase promoter in yeast (Saccharomyces cerevisiae) . More than 10(6) molecules of hormone were formed per cell despite the fact that the gene was constructed with codon preference for Escherichia coli. Eur J Clin Pharmacol, 1985, 29(2), 225 - 9 High performance liquid chromatographic determination of moxalactam in human plasma and cerebrospinal fluid; Nielsen J et al.; A sensitive and reproducible method for the measurement of moxalactam in plasma and cerebrospinal fluid is described . Plasma proteins were removed by precipitation with ice-cold methanol at pH 5.6 and centrifugation . The supernatant was analysed by HPLC on a mu-Bondapack/phenyl column, with a mobile phase of acetonitrile/water/PIC Reagent A (20/80/1), and detection at 280 nm . The calibration curve was linear for plasma concentrations from 10 micrograms/ml to 60 micrograms/ml . Reproducibility was 4.7% (coefficient of variation) for within-day analysis and 13.8% for day-to-day analysis . Plasma concentrations in 9 moxalactam-treated patients with severe infections ranged from 0.9 micrograms/ml to 409 micrograms/ml . Individual pharmacokinetic parameters were calculated using a personal computer . In selected cases moxalactam concentrations were also determined in cerebrospinal fluid and tracheal aspirates. Curr Top Cell Regul, 1985, 26, 177 - 90 On conformational changes in the regulatory enzyme aspartate transcarbamoylase; Cohen RE et al.; Our preliminary studies provide clear answers to only some of the basic questions posed above regarding the nature of conformational changes in ATCase . By exploiting the reverse reaction to develop a kinetic active site titration technique we demonstrated that symmetry-related regions of ATCase are affected equally in the allosteric transition even though the bisubstrate analog is bound to only one of the six active sites . This is a vivid illustration of a "global" change in an enzyme, and it provides powerful support for the view that active site ligands promote a concerted transition of the enzyme from the low-activity to the high-activity conformation . Kinetic experiments show that this conformational change is rapid, requiring only tenths of a second . In contrast, the studies with isolated catalytic subunits provide evidence for a much more local conformational change which occurs after the ligand is bound and which is much slower, lasting over a time period of many seconds . Although the experiments on the holoenzyme do not show directly how many atoms are involved in the conformational change or how large are the displacements, they do indicate, especially in conjunction with other studies, that many amino acid residues in both the catalytic and regulatory chains must be implicated in the T----R allosteric transition . Why PALA has such a different local effect on the catalytic subunit than does the combination of carbamoylphosphate and succinate is not clear, but this uncertainty may be resolved by further NMR studies . Determining how the local changes at the active sites are linked to the global transition affecting the quaternary structure of the enzyme remains a formidable problem . Also further work is needed in order to determine whether unliganded ATCase molecules exist in an equilibrium mixture of T and R conformations even prior to the ligand binding event. Bull Soc Pathol Exot Filiales, 1985, 78(4), 433 - 8 {Regional characteristics of enterotoxigenic Escherichia coli serotypes isolated from children with gastroenteritis in the South Pacific (New Caledonia, Vanuatu Republic, Wallis and Futuna}; Germani Y et al.; One hundred and fifty enterotoxigenic strains of Escherichia coli (ETEC) isolated from infants with acute diarrhoeas in New Caledonia, Vanuatu and Wallis and Futuna were examined for serotypes . Twenty serotypes were identified, 5% of E . coli (7 strains) were rough and 8% (12 strains) were untypable . The serotypes 06, 025, and 078 are enterotoxigenic at 100% . The serotypes 027 and 073 classically enterotoxigenic did not produce any enterotoxin . This study opens up a possibility that the predominant enterotoxigenic serotypes in that region of the South Pacific are probably different from the serotypes proposed in the pool of sera to identify ETEC. J Cell Biochem, 1985, 29(2), 73 - 82 Site-specific mutagenesis of dihydrofolate reductase from Escherichia coli; Chen JT et al.; Two site-specific mutations of dihydrofolate reductase from Escherichia coli based on the x-ray crystallographic structure were constructed . The first mutation (His-45----Gln) is aimed at assessing the interaction between the imidazole moiety and the pyrophosphate backbone of NADPH . The second (Thr-113----Val) is part of a hydrogen bonding network that contacts the dihydrofolate substrate and may be involved in proton delivery to the N5-C6 imine undergoing reduction . The first mutation was shown to alter both the association and dissociation rate constants for the cofactor so that the dissociation constant was increased 6-40-fold . A corresponding but smaller (fourfold) effect was noted in V/K but not in V compared to the wild-type enzyme . The second was demonstrated to increase the dissociation rate constant for methotrexate 20-30-fold, and presumably dihydrofolate also, with a corresponding 20-30-fold increase in the dissociation constant . In this case an identical effect was noted on V/K but not in V relative to the native enzyme . Thus, in both mutant enzymes the decrease in binding has not been translated into a loss of catalytic efficiency. Gene, 1985, 38(1-3), 65 - 72 Nucleotide sequence of the ksgA gene of Escherichia coli: comparison of methyltransferases effecting dimethylation of adenosine in ribosomal RNA; van Buul CP et al.; The ksgA gene of Escherichia coli encodes a methyltransferase (MeT) that specifically dimethylates two adjacent adenosines near the 3' end of 16S RNA in the 30S particle . Its inactivation leads to kasugamycin (Ksg) resistance . Several plasmids were constructed with inserts which complemented chromosomal ksgA mutations . One of these inserts was sequenced and found to contain an open reading frame (ORF) sufficient to code for the previously identified 30-kDal MeT . We have compared the amino acid (aa) sequence of the ksgA-encoded enzyme with three published sequences of MeT involved in dimethylation of an adenosine residue in 23S RNA and rendering the organisms resistant to the MLS antibiotics . The homologous patches in the sequences of all four enzymes suggest that those might correspond to contact points for the common substrates, e.g., for the adenosine residue(s) and S-adenosylmethionine (SAM). Gene, 1985, 38(1-3), 259 - 64 Non-toxic expression in Escherichia coli of a plasmid-encoded gene for phage T4 lysozyme; Perry LJ et al.; The phage T4 gene coding for lysozyme has been cloned into a plasmid under control of the (trp/lac) hybrid tac promoter and expressed in Escherichia coli with no significant toxic effect to actively growing cells . E . coli D1210 (lacIq) transformed with this plasmid produced active T4 lysozyme at levels up to 2% of the cellular protein after induction with isopropyl-beta-D-thiogalactoside . A strain producing active lysozyme was shown to be under a selective disadvantage when co-cultured with a similar strain producing inactive lysozyme . Purified strains, however, are reasonably stable in culture and under normal storage conditions. Gene, 1985, 38(1-3), 145 - 52 Demonstration of remarkable sequence divergence in variants of a complex satellite DNA by molecular cloning; Stringfellow LA et al.; Repeat units of a complex G + C-rich satellite of the Bermuda land crab have been cloned by insertion into either the PstI or EcoRI site of pBR322 or the EcoRI site of pUC9 . While most of the recombinants contained inserts of approx . 2.1 kb, the average size of repeat units seen in cellular satellite digests, several inserts were markedly different in size . Two domains that account for major sequence differences among the satellite variants and that may be 'hotspots' for sequence modification have been subcloned to permit characterization of their secondary and tertiary structures independent of the influence of the other unusual sequences present . One of these domains is striking in its content of simple repeats; one strand is highly biased in pyrimidines which may permit the formation of unusual secondary and/or tertiary conformations . The other subcloned domain is rich in Pu/Py; preliminary data indicate a transition from B----Z DNA in this region. Gene, 1985, 38(1-3), 1 - 8 Cloning of a chloramphenicol acetyltransferase gene of Streptomyces acrimycini and its expression in Streptomyces and Escherichia coli; Gil JA et al.; A gene (cat) for chloramphenicol (Cm) acetyltransferase (CAT) was cloned from Streptomyces acrimycini into S . lividans 66 on the plasmid vector pIJ61 . The cat gene was localized on a 1.7-kb BclI fragment, which probably also carries the cat promoter . This DNA fragment conferred Cm resistance, through CAT activity, on S . lividans, S . coelicolor and S . parvulus, but not on Escherichia coli when inserted in the BamHI site of the tetracycline-resistance(TcR) gene of pBR322 . However, when inserted in a particular orientation in this site, spontaneous deletions of 0.7 kb led to CAT activity and Cm resistance . DNA homologous to the 1.7-kb BclI cat fragment was found in most, but not all, of a series of other streptomycetes that have CAT activity . The cat provides a potentially useful screening marker for Streptomyces cloning vectors. Folia Biol (Praha), 1985, 31(5), 321 - 32 Studies on lipopolysaccharide-induced polyclonal B cell activity in mice tolerized by sheep red blood cells and cyclophosphamide; Fontalin LN et al.; The polyclonal immune response was induced in untreated mice and mice treated with cyclophosphamide by the administration of lipopolysaccharide from E . coli or S . marcescens . The number of cells forming antibodies to sheep red blood cells and to trinitrophenyl, and of cells producing immunoglobulins increased . The administration of LPS to mice pretreated with SRBC and CY (tolerant mice) considerably reduced the number of anti-SRBC AFC in comparison with the controls . The tolerogenic treatment did not change the number of anti-TNP AFC and IPC . Analogous results were obtained in genetically athymic (nude) mice and in B mice (thymectomized, lethally irradiated and reconstituted with embryonic liver cells) . The results suggest that a deletion or a temporary inactivation of a fraction of the antigen-specific B cells occurs in tolerant mice . This inactivation cannot be explained by the absence of expression of surface immunoglobulins on B cells nor by the activity of suppressor T cells. Biol Neonate, 1985, 48(5), 307 - 12 Observations on the development of the febrile response to pyrogen in newborn pigs; Moraes RN et al.; The febrile response of newborn pigs to exogenous pyrogen injection was investigated . Lipopolysaccharides (LPS, E . coli) were injected intravenously into the superior vena cava of 1-30-day-old piglets . All the experiments were carried out in littermates half of which were injected with pyrogen and half with pyrogen-free saline . Newborn pigs did not develop a febrile response from 1 to 4 days of age; however, when the animals were 5 days old exogenous pyrogen determined a typical monophasic febrile response . A second intravenous injection of pyrogen into newborn pigs (1 day old) 24 h after the first did not raise body temperature . It is suggested that newborn pigs behave like the newborn of other mammalian species regarding endotoxin-induced thermogenesis. Basic Life Sci, 1985, 34, 121 - 45 Situation-dependent repair of DNA damage in yeast; von Borstel RC et al.; The concept of channelling of lesions in DNA into defined repair systems has been used to explain many aspects of induced and spontaneous mutation . The channelling hypothesis states that lesions excluded from one repair process will be taken up by another repair process . This is a simplification . The three known modes of repair of damage induced by radiation are not equivalent modes of repair; they are, instead, different solutions to the problem of replacement of damaged molecules with new molecules which have the same informational content as those that were damaged . The mode of repair that is used is the result of the response to the situation in which the damage takes place . Thus, when the most likely mode of repair does not take place, then the situation changes with respect to the repair of the lesion; the lesion may enter the replication fork and be reparable by another route. Acta Microbiol Hung, 1985, 32(2), 183 - 92 Virulence factors of Escherichia coli . II . Antigens O4, O6 and O18, haemolysin production and mannose resistant haemagglutinating capacity are closely associated; Czirok E; Escherichia coli strains isolated from a variety of human samples were examined for alpha haemolysin (Hly) production . A total of 1156 strains was compared for incidence of Hly positivity, and the capacity of mannose resistant haemagglutinating activity of human erythrocytes (MRHA) . Incidence of Hly production in serogroups O4, O6 and O18ac was significantly higher than in other ones (70.1% vs . 18.7%), independently of the origin of strains; 78% of Hly+ strains belonging to serogroups O4, O6, O18 was MRHA+, too . The marked correlation between Hly positivity, MRHA activity and these serogroups suggested that in serogroup O4, O18 and in a lesser degree O6, genetic informations concerning O antigen, MRHA and Hly are linked in the chromosome. Mol Gen Genet, 1985, 201(1), 25 - 9 DNA sequencing of the Escherichia coli ribonuclease III gene and its mutations; Nashimoto H et al.; A 0.7 kb DNA fragment of the Escherichia coli K12 chromosome was shown to contain the structural gene for RNAse III (rnc) . The DNA sequence of the gene was determined and its alteration in an RNAse III defective mutant, AB301-105, was identified . DNA sequence analysis also showed that a secondary-site suppressor of a temperature-sensitive mutation in the E . coli ribosomal protein gene, rpsL, occurred within the rnc gene, providing genetic evidence for the interaction of ribosomal proteins with RNAse III, which in turn acts on the nascent ribosomal RNA during