Adv Shock Res, 1983, 9, 133 - 45 Contractile function of heart muscle isolated from endotoxin-shocked guinea pigs and rats; Parker JL; Cardiac effects of endotoxin shock were compared in left atrial preparations isolated from guinea pigs and rats injected with 4 or 8 mg/kg E coli endotoxin . Heart muscles isolated from both species during endotoxin shock exhibited significant contractile depression which could be reversed by increasing extracellular Ca++ concentrations . Force-frequency relationships were shifted downward by endotoxin shock in both species . However, significant interspecies differences were observed in inotropic responsiveness of heart muscles isolated from shocked rats and guinea pigs . Atria from shocked guinea pigs demonstrated markedly prolonged rates of recovery from the negative inotropic effects of gentamicin (4.0 mM) and a low Ca++ medium (0.5 mM) . In contrast, rates of recovery from these interventions were not altered by endotoxin shock in heart muscle from rats . Furthermore, contractile recovery from 15-min hypoxia was characterized by a significant "overshoot" phenomenon in heart muscles from shocked guinea pigs but not from shocked rats . These data suggest that although endotoxin shock produces cardiac depression in both the rat and the guinea pig, contractile responses to selected inotropic interventions are different and may reflect different cellular sites or mechanisms whereby shock produces cardiac depression in these two species. Am J Clin Pathol, 1983 Jan, 79(1), 65 - 72 A study of optimal reaction conditions for an assay of the human alternative complement pathway; Joiner KA et al.; The optimal conditions for performance of a sensitive functional assay for the human alternative complement pathway were studied . The serum dilution causing 50% lysis of rabbit erythrocytes in magnesium EGTA buffer is designated the APH50 titer . Optimal reaction conditions for the assay were pH 7.2, incubation temperature 37 degrees C, incubation time 60 minutes, and magnesium concentration 0.002 M . Lowering the ionic strength of the buffer from 0.150 M to 0.0125 M increased APH50 titers nearly 2.5-fold, but decreased the reproducibility of titers . Significant fluid-phase conversion of C3 at 37 degrees C in low ionic strength buffer was demonstrated by crossed immunoelectrophoresis . Using the optimal reaction conditions, in normal ionic strength buffer the mean APH50 +/- SD for 45 normal adults was 25.3 +/- 5.7 U/mL . Heparin, an inhibitor of the alternative pathway, decreased APH50 by 50% at a concentration of 100 U heparin/mL serum, and totally abolished alternative pathway hemolytic activity at 1,000 U heparin/mL serum, while lowering CH50 titers to a much lesser degree . When increasing doses of zymosan were used for complement activation in vitro, the per cent APH50 depletion at low doses of zymosan was at least twice the per cent depletion of CH50 or antigenic P, B, and C3 . A striking dichotomy between nearly complete APH50 depletion and normal or near normal CH50 and hemolytic C4 levels was documented for a human burn patient and for a baboon infused with a lethal dose of Escherichia coli lipopolysaccharide . Therefore, we documented a substantially greater sensitivity of APH50 than of conventional complement determinations for detecting complement consumption by alternative pathway activators. Int Arch Allergy Appl Immunol, 1983, 70(1), 92 - 5 Effects of fibrinogen fragment and proteolytic enzyme on the immune system in mice; Ahlstedt S et al.; The immunomodulating ability of fibrinogen fragment (Hol-DSK) and proteolytic enzyme with fibrinolytic activity from Aspergillus oryzae was analysed in CBA/Ca, C57Bl, C3H/HeJ and NMRI mice . Suppressive effects on the blastogenic response to mitogens were noted . No consistent suppressive effect, but sometimes an enhancing one, was recorded on the antibody responses to protein antigens . Administration of Hol-DSK or proteolytic enzyme shortly after the immunization resulted in a slight inhibition of the development of delayed hypersensitivity to picryl chloride in C57Bl but not in CBA mice . When similar administration was done simultaneously with administration of the challenging antigen of picryl chloride or sheep red blood cells in immunized mice, significant impairment of the delayed-type hypersensitivity reaction was noted . The modulating effects by Hol-DSK did not alter the in vitro bacteriocidal effects of peritoneal exudate cells from mice on Escherichia coli. J Comp Pathol, 1983 Jan, 93(1), 9 - 25 Experimental pyelonephritis in the cat: 3 . Collagen alterations in renal fibrosis; McCullagh KG et al.; Chronic pyelonephritis was induced in young adult cats by the intravenous injection of a human or a feline strain of Escherichia coli after ligation of one ureter for 24 or 48 h . In the 3 cats infected with the feline strain, scarred kidneys from the obstructed side were removed at necropsy 3, 4 and 5 months later . Collagen was extracted from pyelonephritic and normal kidney tissue with dilute acetic acid and limited proteolysis with pepsin . Scarred kidneys gave higher yields of both acid-soluble collagen (normal = 0.57 +/- 0.12 mg per g tissue; scarred = 0.88 +/- 0.10 mg per g tissue) and pepsin-solubilized collagen (normal = 9.69 +/- 1.79 mg per g tissue; scarred = 20.02 +/- 2.84 mg per g tissue) . There was no significant increase in the collagen yield from the kidneys of the 2 cats in which mild focal lesions were found 14 and 16 months after infection with the human strain of E . coli . Pepsin released collagens were separated by fractional salt precipitation and identified by agarose gel chromatography and polyacrylamide gel electrophoresis . Normal kidney was shown to contain collagen of Types I, IV and V (AB) . The Type IV collagen extracted consisted of a mixture of 4 major pepsin-resistant chains of apparent molecular weights of 150 000, 115 000, 85 000 and 60 000 . The collagen extracted from scarred kidneys was predominantly Type I, only trace amounts of Type IV and V components being present . These findings suggest that basement membrane collagens of the kidney are selectively degraded during the atrophy and scarring of chronic feline pyelonephritis and are preferentially replaced by interstitial Type I collagen. Circ Shock, 1983, 10(2), 147 - 60 Effects of naloxone on hemodynamics, oxygen transport, and metabolic variables in canine endotoxin shock; Thijs LG et al.; The effects of naloxone (2 mg/kg body weight) on hemodynamics, oxygen transport, and some metabolic variables were studied in mongrel dogs under general anesthesia and controlled ventilation . All 19 dogs received Escherichia coli endotoxin (1.5 mg/kg) and subsequently were randomized into three groups . The first group (N = 7) served as a control group in which at 90 min after endotoxin (t 90), NaCl (0.65%, 4 ml/kg) was infused during 30 min . In the second group (N = 7) naloxone (2 mg/kg) dissolved in the same amount of fluid was administered at t 90 in 30 min . In the third group (N = 5) naloxone (2 mg/kg) was injected as a bolus in 5 ml NaCl (0.65%) at t 90, which was followed by NaCl (0.65%, 4 ml/kg) infused in 30 min . Differences in the three groups after intervention were tested statistically . After naloxone, blood pressure, cardiac output, and left ventricular stroke work increased significantly . Although oxygen availability increased, oxygen consumption and serum lactate did not change when compared with the control group . As to all other measured and calculated variables, no systematic differences were found in the three groups . In six dogs, plasma beta-endorphins were measured and were shown to rise substantially after induction of endotoxin shock . As to the hemodynamic changes, our observations confirm data from the literature . Naloxone apparently improves hemodynamics in endotoxin shock, but at least in this study fails to influence oxygen consumption and serum lactate levels. Prog Food Nutr Sci, 1983, 7(3-4), 157 - 65 Escherichia coli heat-stable enterotoxin: biochemical and physiological effects on the intestine; Giannella RA; E . coli which elaborate suckling mouse active small MW heat-stable enterotoxin (STa), are important causes of diarrhea in animals and man . These STa's share the property of causing intestinal secretion and diarrhea by virtue of inhibiting the absorption of sodium and chloride and possibly stimulating the secretion of chloride . STa's seem to act in the colon as well as the small intestine and the alterations in intestinal ion and water transport are probably mediated by the guanylate cyclase-cyclic GMP system . Glucose transport is unaffected . STa also causes alterations in the myoelectrical activity of the small intestine which may result in the loss of normal peristaltic activity . STa binds in a reversible fashion to specific receptors on the surface of small intestinal and colonic epithelial cells . The mechanisms whereby occupation of the STa receptors lead to activation of the guanylate cyclase system and intestinal secretion are unknown but may involve influx of calcium through calcium channels, stimulation of prostaglandin synthesis and release of free radicals. Prog Food Nutr Sci, 1983, 7(3-4), 147 - 56 Chemical and immunological properties of Escherichia coli heat-stable enterotoxin; Robertson DC et al.; Five heat-stable enterotoxins (STs) produced by enterotoxigenic E . coli (ETEC) strains of porcine, bovine and human origin have been purified to apparent homogeneity . The STs with biological activity in suckling mice and piglets (STA) contained 18 amino acid residues, 10 or 11 different amino acids with a high proportion of acidic amino acids and 6 half-cystines . All 5 purified preparations were heat-stable, not denatured by organic solvents and detergents, resisted protease digestion and treatment at pH 1.0, but were partially inactivated by incubation at pH 12.0 and totally inactivated by reducing and oxidizing agents which disrupted disulfide bonds . The isoelectric point (pI) of the 5 STAs ranged from 3.88 to 4.08 . Antiserum raised against strain 431 ST, a porcine class II enteropathogen, neutralized all 5 STAs and was useful as a reagent in a sensitive radioimmunoassay to detect suckling mouse positive strains of ETEC. Arzneimittelforschung, 1983, 33(10), 1477 - 8 {No effect of particular r-RNA fragments on cytostatic-induced myelosuppression in a rat transplanted tumor model}; Berger M et al.; Particular r-RNA fragments of E . coli (BLR = Beljanski leukocyte restorer) were given together with a high dose combination chemotherapy of a transplanted neurogenic rat tumor . A restoring effect on the myelopoesis that could be exploited therapeutically was not observed after BLR. Arzneimittelforschung, 1983, 33(2a), 290 - 6 {Toxicology of carteolol}; Lang W; Studies of the acute toxicity of 5-(3-tert-butylamino-2-hydroxy-propoxy)-3, 4-dihydro-2(1H)-quinolinone hydrochloride (carteolol hydrochloride, Endak, Endak mite) in various species by different modes of administration revealed comparatively slight necropsy and histological changes despite characteristic clinical features of poisoning, There were only minor discrepancies in LD50 between the different species, and no sex differences were observed . The LD50 was 2000-4000 times the therapeutic dose . Death is thought to be due to excessive enhancement of the pharmacological action of the sympathomimetic component with extreme abnormalities of blood distribution and interference with cardiac and lung function . In subchronic and chronic toxicity tests in rats no effects due to the drug were demonstrable for doses of up to 150 mg/kg . In dogs the highest dose free from side-effects was between 3 and 30 mg/kg . Above 10 times the therapeutic dose there was some increase in brown adipose tissue, but this is not thought to be of any pathological significance . No teratogenic effects were detected in experiments on mice, rats and rabbits, and no embryotoxic or fetotoxic activity was seen except for doses high enough to produce toxic effects in the mother animals . No carcinogenic properties were identified . Tests for mutagenic effects (S . typhimurium, E . coli, cytogenetic studies in rats, dominant lethal test) yielded negative results. Acta Physiol Hung, 1983, 62(3-4), 187 - 90 Effect of thyrotropin (TSH) treatment on the responsiveness of the thyroid gland during endotoxin shock in adult rats; Nagy SU et al.; The shock-inducing dose (1.0 omg/200 g i.v.) of bacterial endotoxin (E coli 089) significantly decreased the serum levels of T4 and inhibited the T4 increasing action of thyrotropin in rats . It is suggested that the changes observed were due to the membrane damaging effect of endotoxin. Dev Biol Stand, 1983, 54, 125 - 30 Expression of hepatitis B surface antigen in yeast; Harford N et al.; The genomes of HBV viruses of two different serotypes were cloned in E . coli . Sequences coding for the major polypeptides of surface antigen (HBsAg) were fused with the 5' end of a cloned yeast arg3 gene . When introduced into yeast, on a suitable vector, the hybrid gene directed the synthesis of a fusion protein . Crude extracts of such strains were shown to contain HBsAg like material having physical properties characteristic of the antigen isolated from the plasma of chronic human carriers, as judged by isopycnic and rate zonal centrifugation . Furthermore, these extracts readily elicit specific anti-HBsAg antibodies in rabbits . Further manipulations of the 5' part of the arg3 gene resulted in the introduction of a unique restriction site located in the 5' non translated leader sequence . The resulting vector was used to construct a recombinant plasmid directing the synthesis of the mature (226 amino acids) HBsAg polypeptide. EMBO J, 1983, 2(7), 1145 - 9 Apparent relatedness of the main component of ovine 1.714 satellite DNA to bovine 1.715 satellite DNA; Reisner AH et al.; The nucleotide sequence of the principal component of ovine 1.714 g/cm3 satellite DNA was determined from a monomeric fragment inserted at the BamHI site of pBR322 and cloned in Escherichia coli strain RR1 . The 816-bp tandemly repeated sequence contains a number of small repeated sequences dispersed within it, one group of which forms a pentameric tandem repeat of a 13-bp segment (positions 548-612) . A 20-bp region (60-79) shows an 85% homology with the reverse-complement of the sequence from 455 through 474 . There are two regions of 67 bp (75-141) and 59 bp (755-813) which show greater than 70% homology with regions of bovine 1.715 g/cm3 satellite DNA (1402 bp; positions 1218-1284 and 1079-1137, respectively) while a 31-bp region (ovine 62-92, bovine 133-163) shows 80% homology . Quasi-correlation coefficients (Qr) were determined using the triplet numbers of the sheep satellite versus all sequences in the National Biomedical Research Foundation and EMBL nucleotide sequence data bases . Qr equals 0.85 for ovine 1.714 g/cm3 satellite versus bovine 1.715 g/cm3 satellite . The next highest Qr for a bovine satellite segment was 0.58 . Thus, the ovine 1.714 g/cm3 and bovine 1.715 g/cm3 satellite appear demonstrably related . Taking into account that sheep and cattle diverged 18-20 million years ago, this suggests that the material may be functional and that its function is related to its sequence. Immunol Commun, 1983, 12(4), 397 - 406 Modulation by zinc of the in vitro antibody response to T-dependent and T-independent antigens; Malave I et al.; The influence of zinc on the in vitro antibody response to antigen or mitogen stimulation was studied by adding various concentrations of ZnCl2 to cultures of spleen cells stimulated with sheep erythrocytes, trinitrophenyl-lipopolysaccharide or with the polyclonal B cell activator E . coli lipopolysaccharide (LPS) . Addition of ZnCl2 in concentrations ranging from 10(-8) or 10(-7) to 10(-5) M increased the specific antibody response to antigens or the polyclonal antibody synthesis induced by stimulation with LPS, when the response of the assayed population in the control cultures without ZnCl2 was low, as observed in cultures without 2-mercaptoethanol (2-ME) . However, in cultures supplemented with 2-ME, the potentiating effect of ZnCl2 diminished or disappeared or even the antibody response was inhibited . Higher concentrations of ZnCl2 markedly depressed (5 X 10(-5) M) or abolished (10(-4)) the in vitro induced antibody response in all cultures . The various mechanisms which could mediate the effects of zinc are discussed. Radiat Environ Biophys, 1983, 21(4), 281 - 94 Accumulation and lethal effect of tritium (tritiated water) in Rhodopseudomonas spheroides . Under light-anaerobic and dark-aerobic conditions; Inomata T; Nonsulfur purple photosynthetic bacteria, Rhodopseudomonas spheroides cells were cultured in medium containing tritiated water (THO) under the light-anaerobic and dark-aerobic conditions . The experimental R value defined as specific activity ratio of organic bound 3H to THO in medium was 0.49 and 0.48 for the light-anaerobically grown cells and the dark-aerobically grown cells, respectively . From the relation of R value to number of weight doubling of the cells (n), ratio of experimental R to theoretical R, i.e., (2n-1)/2n derived by assuming no isotope effect, was 0.51 and 0.49 on an average for the light-anaerobically grown cells and the dark-aerobically grown cells, respectively . 3H-incorporation from THO-medium into the light-anaerobic nongrowing cells was affected by the light intensity and suppressed by adding HgCl2, KCN, and 2,4-dinitrophenol as well as 3H-labelling in the dark-aerobic nongrowing cells was affected by oxygen tension and suppressed by adding these metabolic inhibitors . From the fractionation of the lyophilized cells by modified Schneider method, the distribution of exchangeable 3H in cold acid-soluble and ether-ethanol-soluble fractions and nonexchangeable 3H bound to small molecules and macromolecules was 7.4/25.3/67.3 in the growing cells cultured anaerobically in the THO-medium up to late exponential phase in the light . The distribution in the nongrowing cells incubated anaerobically with the THO-medium for 18 h in the light of 300 and 3,000 lux was 82.1/8.4/9.5 and 58.2/19.2/22.6, respectively . These distributions of 3H were changed with growth phase and/or incubation time . On the biological effect of 3H-THO for the cells stocked at -196 degrees C to accumulate 3H-decays, the dark-aerobic nongrowing cells labelled with THO were rather radiosensitive than the dark-aerobically and light-anaerobically grown cells cultured in the THO-medium . The killing efficiencies, i.e., the probability that a single disintegration would be lethal, ranged from 1/200 to 1/275 for the above three kinds of cells labelled with THO . The killing efficiencies for R . spheroides labelled with THO were similar to that for radiosensitive strain CB13 and wild strain Hfr of Escherichia coli labelled with 3H-thymidine and stored at -196 degrees C. J Exp Med, 1983 Jan 1, 157(1), 155 - 72 Stages of renal ontogenesis identified by monoclonal antibodies reactive with lymphohemopoietic differentiation antigens; Platt JL et al.; Differentiation antigens of T and B lymphocytes were sought in human fetal and adult kidney tissues with monoclonal antibodies by indirect immunofluorescence . Antibodies that identify B cells (BA-1 and anti-B1) and leukemia-associated antigens (BA-2, BA-3, and J5) reacted with renal glomerular and tubular epithelium at characteristic stages of nephron development . BA-1 and BA-2 identified primitive epithelium of the glomerulus, and ureteral bud and nephron development was characterized by loss of BA-1 and BA-2 binding by visceral glomerular and proximal tubular epithelium . In contrast, J5 and BA-3 did not react with primitive epithelium but identified visceral and proximal tubular epithelium after appearance of the glomerular basement membrane and throughout subsequent nephron differentiation . Anti-B1 reacted with ureteral bud and distal nephron epithelium in more mature fetal tissues . Monoclonal antibodies that identify populations of T cells and thymocytes did not react with parenchymal cells of fetal or adult kidneys . They did identify interstitial mononuclear cells whose size and relative numbers appeared gestationally related . Monoclonal antibodies that recognize a human monomorphic HLA-DR determinant reacted with glomerular and peritubular capillaries as early as 11 wk of gestation . The distribution and density of HLA-DR expression appeared more related to gestation than nephron development . The relationship between renal parenchymal expression of lymphohemopoietic antigens and glomerular acquisition of C3b receptor activity was determined using C3b-coated fluoresceinated Escherichia coli . In fetal tissues, C3b receptor activity appeared developmentally related to the loss of determinants recognized by BA-1 and BA-2 and to the appearance of J5 and BA-3 reactivity with visceral glomerular epithelium . Tissue binding and comparative avidity of J5 and BA-3 antibodies was studied in a series of experiments, the results of which suggest that these antibodies are directed against the same epitope or closely related epitopes of the common acute lymphoblastic leukemia antigen . The common expression of differentiation antigens and C3b receptors by cells of lymphohemopoietic lineage and renal epithelia suggests the possibility of heretofore unrecognized commonality of function or developmental experience. Proc Natl Acad Sci U S A, 1983 Jan, 80(2), 349 - 52 Isolation of cDNA sequences coding for a part of human tissue plasminogen activator; Edlund T et al.; We have isolated a cDNA sequence coding for a part of human tissue plasminogen activator . mRNA coding for tissue plasminogen activator was partially purified, copied into double-stranded cDNA, and cloned into Escherichia coli . Two sets of partially overlapping oligodeoxynucleotide mixtures corresponding to all possible coding sequences for a known portion of the tissue plasminogen activator gene were prepared . One set was used as a probe to screen cDNA containing bacterial clones and both were used as probes in hybridization against purified plasmid DNA . Of 4,200 bacterial clones examined, 1 carried a plasmid that hybridized to both sets of oligonucleotides . This plasmid contained a 370-base-pair cDNA insert, which was shown by nucleotide sequence analysis to code for the cleavage site region in the one-chain form of the human tissue plasminogen activator. Med Pediatr Oncol, 1983, 11(1), 1 - 7 Prolonged second remissions in childhood acute lymphocytic leukemia: a report from the Childrens Cancer Study Group; Baum E et al.; To date, median duration of second and subsequent remissions in childhood acute lymphocytic leukemia (ALL) has been short, with most studies reporting median remission duration less than 6 months . In May 1979, the Childrens Cancer Study Group (CCSG) undertook a pilot study to assess the efficacy of a vincristine, methotrexate, and L-asparaginase regimen (modified Capizzi) for maintenance in children with ALL in second or subsequent remission . Thirty patients were treated with this maintenance regimen . By life table analysis, predicted median duration of hematologic remission was 57 weeks . Ten patients (33%) were in continuous hematologic remission at 1 year and three (10%) continue in remission greater than 2 years from maintenance onset . Major toxicity included leukoencephalopathy in four patients, three of whom had experienced at least one central nervous system relapse prior to study entry . Allergic reactions to Escherichia coli L-asparaginase were common . Nine of 30 patients experienced at least one CNS relapse during therapy . We conclude that a modified Capizzi regimen is the most effective regimen reported to date for maintaining second and subsequent remission in childhood ALL . CCSG is currently utilizing this regimen in an ongoing open study. Proc Natl Acad Sci U S A, 1983 Jan, 80(1), 250 - 4 Cloning and expression of DNA sequences associated with the killer trait of Paramecium tetraurelia stock 47; Quackenbush RL et al.; We have presented direct evidence that at least one of the traits associated with killing of paramecia by kappa particles is determined by an extrachromosomal genetic element . Plasmid DNA was isolated from Caedibacter taeniospiralis 47 (commonly known as 47 kappa), which is an obligate cytoplasmic endosymbiont of Paramecium tetraurelia . Fragments of pKAP47 DNA generated by Pst I digestion were inserted into pBR328 and then introduced into Escherichia coli 294 by transformation . Clones carrying recombinant plasmids were screened for toxicity toward sensitive strains of paramecia or for the ability to produce R bodies . None of the clones appeared to be toxic . However, three clones were found to have the ability to produce R bodies, which are proteinaceous ribbons (10-20 microns long, 0.5 microns wide, and 13 nm thick) rolled up inside the cell to form a hollow cylinder about 0.5 microns in diameter and 0.5 microns long . Each of these clones carry plasmids that contain the Pst I B fragment from pKAP47 . Subclones of one of the recombinant plasmids, pBQ51, were constructed to determine the approximate location of DNA sequences necessary for R-body synthesis . The left-hand boundary of the required sequences was found to occur within a 600-base-pair region, and the location of the right-hand boundary was determined to occur within a 700-base-pair region . The minimum and maximum sizes of sequences required for R-body synthesis are between 1,300 and 2,600 base pairs. J Bacteriol, 1983 Jan, 153(1), 535 - 8 Interactions of DNA replication factors in vivo as detected by introduction of suppressor alleles of dnaA into other temperature-sensitive dna mutants; Blinkowa A et al.; Suppressor mutations located within dnaA can suppress the temperature sensitivity of a dnaZ polymerization mutant, indicating in vivo interaction of the products of these genes . The suppressor allele of dnaA {designated dnaA(SUZ, Cs)} could not be introduced, even at the permissive temperature, by transduction into temperature-sensitive (Ts) dnaC or dnaG recipients; it was transduced into dnaB(Ts) and dnaE(Ts) strains but at very low frequency . Recipient cells which were dnaA+ dnaE(Ts) were killed by the incoming dnaA(SUZ, Cs) allele, and it is presumed that combinations of dnaA(SUZ, Cs) with dnaB(Ts), dnaC(Ts), or dnaG(Ts) are lethal also . In one specific case, the lethality required the presence of three alleles: the incoming dnaA suppressor mutation, the resident dnaA+ gene, and the dnaB(Ts) gene . This was shown by the fact that dnaB(Ts) could readily be introduced into a dnaA(SUZ, Cs) dnaB+ recipient . That is, in the absence of dnaA+, the dnaA suppressor and dnaB(Ts) double mutant was stable . One model to explain these results proposes that the dnaA protein functions not only in initiation but also in the replication complex which contains multiple copies of dnaA and other replication factors. J Cell Biochem, 1983, 23(1-4), 231 - 40 Substrate and phospholipid specificity of the purified mannitol permease of Escherichia coli; Jacobson GR et al.; D-Mannitol is transported and phosphorylated by a specific enzyme II of the phosphotransferase system of Escherichia coli . This protein was purified previously in detergent solution and has been partially characterized . As one approach in understanding the structure and mechanism of this enzyme/permease, we have tested a number of sugar alcohols and their derivatives as substrates and/or inhibitors of this protein . Our results show that the mannitol permease is highly, but not absolutely, specific for D-mannitol . Compounds accepted by the enzyme include those with substitutions in the C-2(= C-5) position of the carbon backbone of the natural substrate as well as D-mannonic acid, one heptitol and one pentitol . All of these compounds were both inhibitors and substrates for the mannitol permease except for D-mannoheptitol, which was an inhibitor but was not phosphorylated by the enzyme . No compound examined, however, exhibited an affinity for the enzyme as high as that for its natural substrate . We have also investigated the phospholipid requirements of the mannitol permease using phospholipids purified from E coli . The purified protein was significantly activated by phosphatidylethanolamine, but little activation was observed with phosphatidylglycerol or cardiolipin . These observations partially delineate requirements for interaction of sugar alcohols and phospholipids with the mannitol permease . They suggest approaches for the design of specific active site probes for the protein, and strategies for stabilizing the enzyme's activity in vitro. Mol Gen Genet, 1983, 192(3), 309 - 15 Analysis of the antimutagenic effect of cinnamaldehyde on chemically induced mutagenesis in Escherichia coli; Ohta T et al.; The antimutagenic effect of cinnamaldehyde on mutagenesis was investigated using ten kinds of chemical mutagen in Escherichia coli WP2s (uvr A-) . In addition, the frequency of mutation induction by each mutagen in an SOS repair deficient (umuC-) strain was compared with that in a wild-type (umuC+) strain . Cinnamaldehyde greatly suppressed the umuC-dependent mutagenesis induced by 4-nitroquinoline 1-oxide (4-NQO), furylfuramide or captan . However, cinnamaldehyde was less effective against the umuC-independent mutagenesis by alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine and ethylmethanesulfonate . On the other hand, no inhibitory effect of cinnamaldehyde was observed on prophage induction or tif-mediated filamentous growth . These results suggest that a cinnamaldehyde does not prevent the induction of the SOS functions . Despite the decrease in the number of revertants, a remarkable increase was observed in the survival of 4-NQO-treated WP2s cells after exposure to cinnamaldehyde . The reactivation of survival suggests the promotion of some DNA repair system by cinnamaldehyde . This enhancement of survival was also observed in uvr B, polA, recF or umuC mutants and less in lexA or recB, C mutants . However, it was not observed in recA mutants . Therefore, we assume that cinnamaldehyde may enhance an error-free recombinational repair system by acting on recA-enzyme activity. Arch Toxicol Suppl, 1983, 6, 258 - 60 2 Methylene-beta-alanine methyl ester: a toxic amino acid originating from the sponge Fasciospongia cavernosa; Neeman I; N-acyl-2-methylene-beta-alanine methyl esters (A) are the main lipidic compounds in the sponge Fasciospongia cavernosa . These compounds were isolated and after methanolysis--2 methylene-beta-alanine methyl esters (AA) and free fatty acid methyl esters were obtained . The interaction of A and AA with the thiol group of cysteine was detected by Ellman's procedure . Both A and AA interact with the thiol group of cysteine in the pH range of 6.0-8.0 . Both compounds were found to be strong inhibitors of glyceraldehyde triphosphate dehydrogenase (TPD) from rabbit muscle . The inhibitory effect of A and AA decreases upon addition of beef extract and other protein mixtures containing thiol groups . E . coli growth on a synthetic medium was inhibited by compound AA . Resistant E . coli varieties were isolated by techniques of enrichment cultures . Some of these resistant varieties were shown, by cross-feeding with cysteine dependent E . coli varieties, to excrete cysteine and cysteine derivatives. C R Seances Acad Sci III, 1983, 296(21), 989 - 94 {Inhibition of plasmid transfer in Escherichia coli by oxolinic acid}; Michel-Briand Y et al.; Oxolinic acid inhibits the appearance of transconjugants between Escherichia coli harbouring RP4/R6K plasmids and recipient strains . This effect is detected from 1 microgram/ml, (3, 8 microM) without loss of viability, and is not due to a curing process. Mol Gen Genet, 1983, 191(1), 46 - 50 The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans; Tomioka N et al.; The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans, has been determined . Its coding region is estimated to be 1,487 base pairs long, which is nearly identical to those reported for chloroplast 16S rRNA genes and is about 4% shorter than that of the Escherichia coli gene . The 16S rRNA sequence of A . nidulans has 83% homology with that of tobacco chloroplast and 74% homology with that of E . coli . Possible stem and loop structures of A . nidulans 16S rRNA sequences resemble more closely those of chloroplast 16S rRNAs than those of E . coli 16S rRNA . These observations support the endosymbiotic theory of chloroplast origin. C R Seances Acad Sci III, 1983, 296(16), 767 - 70 {Baudot's code, weft of the genetic code}; Cullmann G et al.; Enumerating Bn numbers using only Bn figures is possible thanks to an overlapping reading of a cyclic sequence built according to Baudot's code . This code allows the genetic code to be screened to show the distribution of the synonyms of the aminoacids . The assignments of the genetic code obey strict laws of optimisation of resistance against the effects of mutations. Adv Shock Res, 1983, 9, 43 - 7 Effects of gabexate mesilate on the reactions of lipid metabolism in endotoxic shock; Schmahl FW et al.; Endotoxic shock was induced in rabbits of either sex by IV injection of 50 micrograms/kg endotoxin (ET) extracted from E coli O-55 by Boivin's method . A polyvinyl catheter was introduced into the superior vena cava under local anesthesia 1 day prior to the experiments . We observed a rise of plasma-free fatty acids (FFA) from an initial mean value of 190 muEq/liter to a level of 290 muEq/liter within 6 h after injection of endotoxin . The increase of FFA was followed by a rise of plasma triglycerides (TG) and an increase of very low-density lipoproteins (VLDL), beginning 1-2 h later . The rise of FFA and the following increase of TG and VLDL were significantly reduced by infusion of 14 micrograms/kg X min gabexate mesilate (GM) . Our results indicate that GM--in addition to its well-known proteinase inhibitory action--effects fatty acid metabolism. Dev Biol Stand, 1983, 53, 113 - 21 The use of the Biken test to detect enterotoxigenic "Escherichia coli" producing heat labile enterotoxin; Takeda Y et al.; For identification of enterotoxigenic Escherichia coli producing heat labile enterotoxin (LT), various assay methods have been developed . However, many of these assay methods are unsuitable for routine clinical purposes, especially in developing countries, because they need special materials or techniques or both, such as a large number of animals, stocks of special tissue culture cells, and radioisotopes . Recently, we developed a simple and reproducible assay method, Biken test, which can be widely used in clinical laboratories in both developing and developed countries (15) . This method is based on the principles of the Elek test and Ouchterlony double gel diffusion test . The Biken test was used in a field study in Bangladesh with good results (14) . Moreover, the Diarrheal Diseases Control Programme, WHO, organized a multi-laboratory study to evaluate the accuracy and reproducibility of the Biken test, in which 5 investigators tested an identical set of 100 unknown strains of E . coli, using the Biken test and at least one other assay method, which includes CHO cell assay, Y1 adrenal cell assay, GM1 ganglioside ELISA, DNA probe test and passive immune hemolysis . The results reported by Sutton (International Symposium on Bacterial Diarrheal Diseases, Osaka, 1982) showed that the Biken test was a reliable assay method . To evaluate further the Biken test, we tested a total of 2,229 strains of E . coli isolated from diarrheal patients . The results showed 99.0% coincidence with those obtained by CHO cell assay . The use of anti-LT antiserum gave sharper and clearer results than cholera antitoxin . Samples for heat stable enterotoxin (ST) assay were obtained from the agar plates used for the Biken test and the ST activities of these samples were compared with those of samples obtained from standard liquid cultures . Results on samples of 2,229 strains from the Biken agar plates and from liquid cultures were almost identical. Carcinogenesis, 1983, 4(7), 889 - 93 Preferential binding of aflatoxin B1 to the transcriptionally active regions of rat liver nucleolar chromatin in vivo and in vitro; Yu FL; The literature on various isolated carcinogen-DNA adducts indicates clearly that the binding of chemical carcinogens to DNA is highly specific . Since DNA in eukaryotic cells is complexed with chromosomal proteins and organized into transcriptionally active and inactive chromatin, chemical carcinogens also might show binding specificities at the chromatin level . Using Escherichia coli RNA polymerase and the endogenous engaged RNA polymerase I as specific probes to monitor respectively the physiologically inactive and active nucleolar chromatin template function, this paper reports that aflatoxin B1, after metabolic activation either in vivo or in vitro, binds preferentially to the physiologically active regions of rat liver nucleolar chromatin, and that this binding specificity is largely lost after the removal of chromosomal proteins from the nucleoli. Mol Gen Genet, 1983, 189(2), 351 - 4 Multiple regulation involved in the expression of the uxuR regulatory gene in Escherichia coli K-12; Ritzenthaler P et al.; We have isolated a strain carrying a fusion of the beta-galactosidase structural gene to the promoter of the uxuR regulatory gene with the aid of the Casadaban Mud (Aprlac) phage . Analysis of mutants with deletions that were derived from the uxuR::Mud1 insertion strain confirmed the counterclockwise transcription direction of the uxuR gene . The uxuR-lacZ fusion strain was also used to examine the regulation of expression from the uxuR promoter . It was observed that an increase in the copy number of the uxuR gene results in an increased repression of beta-galactosidase synthesis . Overproduction of the exuR repressor also caused a decrease of the beta-galactosidase level . In all cases, the repression of beta-galactosidase synthesis was accompanied by a stronger repression of uxuB gene product synthesis . These results indicate that the expression of the uxuR gene is repressed by its own product but also by the exuR repressor . The different types of regulation of the two uxu operons are thus identical. Folia Microbiol (Praha), 1983, 28(1), 28 - 35 Peculiarities of the fatty acid composition of Bdellovibrio; Andreev LV et al.; The fatty acid composition of twelve Bdellovibrio strains isolated upon the growth on bacteria of various taxonomic groups was studied . A dependence of the lipid composition of bdellovibrios on that of bacteria they were parasitizing on was shown . Data pointing to the selective incorporation of fatty acids of host bacteria by bdellovibrios were obtained . Bdellovibrio membranes were shown to contain monounsatured fatty acids with different positions of double bonds indicating that there are at least two alternative mechanisms of synthesis of these acids in the parasites. Biochimie, 1983 Jan, 65(1), 49 - 52 Inhibition of human leucocyte elastase by polynucleotides; Lestienne P et al.; We have found that nanomolar range concentrations of transfer RNA inhibit human leucocyte elastase activity against synthetic or natural substrates . Titration curves give a stoichiometry of 9 +/- 1 elastase molecules inhibited per tRNA molecule . The interaction seems essentially electrostatic since similar inhibitions were measured with poly r(A) or calf thymus DNA, and because the increase in ionic strength leads to a decrease of inhibition . This observation appears to be specific of human leucocyte elastase since porcine pancreatic elastase, and both human and bovine chymotrypsins are not inhibited by tRNA. Arch Biochem Biophys, 1983 Jan, 220(1), 263 - 71 Importance of hydroxyls at positions 3, 4, and 6 for binding to the "galactose" site of beta-galactosidase (Escherichia coli); Huber RE et al.; Values of kinetic inhibition constants representing dissociation constants of inhibitors interacting with the free form of beta-galactosidase ('galactose" site) were determined for a large number of monosaccharides and alcohols . The studies showed that when hydroxyl groups were present at positions 3, 4, and 6 and were in the same orientation as in galactose, binding to the 'galactose" site was good . Alterations in the position of or a lack of a hydroxyl at any of these three positions decreased binding dramatically . The overall binding specificity thus depends to a large extent on these three positions . Positions 3 and 4 were critical . A misorientation at either position eliminated most of the binding . Position 6 was a little more independent . The absence of a hydroxyl at that position did not totally eliminate the binding . The position 2 hydroxyl did not seem to be important for binding as its absence or orientation had only a small effect on the binding capacity . Studies regarding position 5 were inconclusive but since a minimum of four hydroxyl groups seemed important for binding and since positions 3, 4, and 6 are important the 5 position may also be of significance . The work also showed that p-nitrophenyl-beta-D-glucopyranoside, p-nitrophenyl-beta-L-arabinofuranoside, p-nitrophenyl-beta-D-xylopyranoside, cellobiose, and gentiobiose were not substrates in spite of the fact that the nitrophenyl groups made some of these bind quite well . Thus, not only are the presence and configuration of the hydroxyls at positions 3 and 4 important for binding, they are also important in catalysis . p-Nitrophenyl-beta-D-fucopyranoside was a substrate indicating that the 6 position hydroxyl is not as important for production binding as are the hydroxyls at positions 3 and 4. Eur J Biochem, 1983 Jan 1, 129(3), 571 - 82 The catalytic mechanism of tryptophan synthase from Escherichia coli . Kinetics of the reaction of indole with the enzyme--L-serine complexes; Lane AN et al.; The mechanism by which indole condenses with L-serine in the active site of tryptophan synthase was studied by the stopped-flow technique . The single turnover occurs by rapid binding of indole to the pre-formed enzyme--L-serine complex, followed by C--C bond formation, reprotonation of the alpha carbon carbanion of L-tryptophan, and its final release . The effects of isotopic substitution at C-3 of indole, of pH, and of the presence of indolepropanol phosphate on these processes were also studied . The mechanism of binding of indole complements the known mechanisms of binding of L-serine and L-tryptophan to give a detailed picture of the mechanism of catalysis . It invokes two competent species of enzyme--L-serine complexes, leading to a branched pathway for the central condensation process . The rates of dehydration of L-serine and reprotonation of the carbanion of L-tryptophan are probably limited by rearrangements at the active site . Analysis of absorption, fluorescence and circular dichroic spectra, as well as of published data on the stereoisomers obtained by reduction with borohydride, suggests that the rearrangement includes a reorientation of the pyridoxal phosphate C-4' atom . The mechanism provides a detailed framework for explaining all available information, including the activating effect of the alpha subunit on the reaction catalyzed by the beta 2 subunit. Eur J Biochem, 1983 Jan 1, 129(3), 561 - 70 The mechanism of binding of L-serine to tryptophan synthase from Escherichia coli; Lane AN et al.; The mechanism of binding of L-serine to tryptophan synthase, which is the initial phase of the catalytic mechanism, has been studied by steady-state and stopped-flow kinetic techniques . The dependence of three separable rate processes on the concentration of L-serine is compatible with four different enzyme-substrate complexes, one of which lies on a branch in the pathway . By use of L-serine deuterated at the alpha carbon, it is possible to assign the deprotonation of the external aldimine of L-serine with pyridoxal 5'-phosphate to the most rapid observable binding step . Measurements at two pH values show that the rate-determining step in the synthesis of L-tryptophan changes from release of L-tryptophan at the optimal pH of 7.6 to the binding of L-serine at pH 6.5 . Measurements at pH 7.6 in the presence of the substrate analogue indolepropanol phosphate show that the stronger binding of L-serine is probably due to stabilization of the catalytically competent enzyme--L-serine complex . At pH 7.6 L-serine is bound far more slowly to the beta 2 subunit than to the alpha 2 beta 2 complex of tryptophan synthase and retains its alpha carbon proton . For the beta 2 subunit, the rate-determining step of tryptophan synthesis is deprotonation of bound L-serine . The effect of bound alpha subunit is to increase both the rate of deprotonation and beta-elimination, shifting the rate-limiting step to the release of L-tryptophan. Comp Immunol Microbiol Infect Dis, 1983, 6(1), 51 - 6 Persistent plaque formation in experimental murine brucellosis; Schneerson-Porat S et al.; Primary plaque forming cells (PFC) are present in spleens of mice 150 days or more following an infection with Brucella abortus . The development of primary plaques in mice long after antigenic challenge is an uncommon phenomenon, unlike the plaque formation (PF) induced by a non-living antigen . The mechanism of this persistent PF has been now investigated in light of a prolonged persistence of the corresponding antigen in tissues . Living E . coli, inoculated in massive dose into mice, survived in their organs for a brief time, while concomitantly PFC disappeared by day sixteen . Infection with B . abortus, in contrast, induced persistent presence of bacteria in the organs of inoculated mice and stimulated long lasting plaque formation . Only direct plaques were found during all stages of infection . Repeated inoculations of dead B . abortus also induced continuous production of primary plaques, whereas an interval in supply of the antigen resulted in disappearance of PFC . Rifampin (40 mg/kg) eliminated bacteria from the treated mice, which resulted in the disappearance of primary PFC . It seems likely that long lasting PF in B . abortus infected mice is connected with a constant antigenic stimulus operating in the carrier state. Infect Immun, 1983 Jan, 39(1), 394 - 402 Isolation, purification, and partial characterization of Brucella abortus matrix protein; Moriyon I et al.; Peptidoglycan sacculi with peptidoglycan-associated proteins were prepared from cell envelopes of Brucella abortus by extraction with sodium dodecyl sulfate (SDS) at 50 degrees C . On extraction of these preparations with SDS at 100 degrees C, a protein was obtained whose removal from peptidoglycan was confirmed by electron microscopy . Incubation of the 50 degrees C SDS-extracted cell envelopes with 50 mM MgCl2 in SDS-2-beta-mercaptoethanol at 37 degrees C also extracted the protein, along with lipopolysaccharide . At temperatures below 60 degrees C, the protein did not bind SDS strongly and had an apparent molecular weight greater than 92,000 in SDS-polyacrylamide gel electrophoresis . At higher temperatures, SDS bound strongly, and the apparent molecular weight was 38,000 . Urea at 5 M did not alter the electrophoretic mobility of this 38,000-molecular-weight form . Immunoelectrophoresis in detergents with antisera to cell envelopes, carbohydrate staining of SDS-polyacrylamide gels, and production of anti-lipopolysaccharide antibodies by mice immunized with the purified protein indicated that lipopolysaccharide was present in free and protein-bound forms . Sequential gel filtration in SDS-EDTA and SDS-NaCl removed most lipopolysaccharide . After further purification by preparative SDS-polyacrylamide gel electrophoresis, a gas-liquid chromatographic analysis showed residual lipid tightly associated with the protein . The results suggested that the interactions between matrix proteins and other outer membrane components are stronger in B . abortus than in Escherichia coli, which was used as a control throughout. Biochem Soc Symp, 1983, 48, 233 - 44 A hybrid promoter and portable Shine-Dalgarno regions of Escherichia coli; De Boer HA et al.; A gene expression system of Escherichia coli is described here that contains a portable Shine-Dalgarno region . Transcription of this system is under the direction of a hybrid promoter derived from trp and lac-UV5 promoter sequences which is followed by a region that encodes the portable Shine-Dalgarno (PSD) region . Using a series of synthetic PSD regions we varied the length (from 4 to 13 bases) of the Shine-Dalgarno region by increasing the number of bases on the mRNA that are complementary to the 3'-end of 16S rRNA . We found that increase of the Shine-Dalgarno region to 8 or 13 bases decreases the translation efficiency of the chimaeric leucocyte interferon messenger by 40% . We also varied in another series of PSD regions the four bases that follow the Shine-Dalgarno region . We found that the presence of four A residues or four T residues in this region results in the highest translation efficiency . The presence of four C residues reduces the translation efficiency by 50% as compared with PSD regions with A or T residues . The presence of four G residues following the Shine-Dalgarno region lowers the translation efficiency by 75% with respect to PSD regions with A or T residues. J Cyclic Nucleotide Protein Phosphor Res, 1983-84, 9(6), 435 - 48 Regional homology in GTP-binding proto-oncogene products and elongation factors; Halliday KR; The mammalian ras proteins and the bacterial elongation factors share the ability to interact with guanine nucleotides . Comparison of the amino acid sequences has revealed the presence of multiple homologous regions common to all members of the ras and elongation factor families . Two homologous regions share sequence similarities and predicted secondary structure with areas of the elongation factors which have been implicated in GTP binding, suggesting that these regions are part of a common GTP-binding domain . Two other homologous regions contain critical amino acids for the activation of the transforming potential of the mammalian ras proteins . The predicted secondary structure containing residue 61, but not 12, is the same for the ras proteins and elongation factors . It is proposed that the aligned homologous regions surrounding position 12 constitute common functional binding sites with different specificities; by analogy to other GTP-binding proteins, a likely candidate to interact at such a site is a GTPase-subunit. Natl Inst Anim Health Q (Tokyo), 1983 Winter, 23(4), 158 - 60 Changes in leukocyte count, blood glucose and coagulation system in calves injected with Escherichia coli endotoxin; Yagi Y et al.; Responses of leukocyte, blood glucose and coagulation system in calves were investigated to injection with Escherichia coli endotoxin . Severe leukopenia and hyperglycemia following transient hypoglycemia were noted within 24 hours after injection . In the coagulation system, a definite decrease in platelet count, prolongation of prothrombin time and activated partial thromboplastin time were observed . Fibrinogen, soluble fibrin monomer complex and clotting time, however, varied. Ann Rech Vet, 1983, 14(4), 522 - 5 Infection with enterotoxigenic Escherichia coli in calves and protection of the calves by vaccination of the dams; Krogh HV; A report is given of a study on the occurrence of enterotoxigenic Escherichia coli in calves in Denmark . Samples from 1379 1-30-day-old calves were examined and ETEC were isolated from 228 samples (16.5%) . While in 1-2-day-old calves nearly one half (47.5%) harboured ETEC, the frequency dropped to 3.4% in 8-day-old calves, and of 165 9-30-day-old calves just one was found to harbour ETEC . A field trial with K99-containing bacterins was performed in 14 herds with ETEC problems . A total of 109 cows were vaccinated with a 4-strain bacterin and 73 with a K99-bacterin, while 114 cows served as controls . Sixteen calves from the 4-strain bacterin group, 6 calves from the K99-bacterin group, and 25 calves from the control group, became diarrheic within their first week of life. Ann Rech Vet, 1983, 14(4), 487 - 92 The role of dietary antigen in the aetiology of post weaning diarrhoea; Miller B et al.; Experiments were undertaken to investigate whether a hypersensitivity response to dietary antigen might be a predisposing factor in the aetiology of post weaning diarrhoea . The results indicated that: 1 . very small amounts of food given to baby pigs before weaning significantly increased the severity and accelerated the onset of the disease; 2 . post weaning diarrhoea was dependent upon the presence within the diet of antigenic material; 3 . weaning diets containing little antigenic material had less effect upon sucrase levels in the brush borders than did diets rich in antigens . These results are discussed in relation to the hypothesis that immune mediated intestinal damage may predispose to post weaning diarrhoea. Acta Microbiol Hung, 1983, 30(3-4), 239 - 45 Effect of an irradiated Escherichia coli endotoxin reparation on the sensitivity to a lymphotropic cytostatic agent in germfree and conventional mice; Anderlik P et al.; A 18 mg/kg dose of dianhydrodulcitol, a lymphotropic cytostatic agent produced the same death rate among germfree as a 12 mg/kg dose did in conventional mice . Pretreatment with the same dose of an irradiated immunomodulatory endotoxin preparation had increased the sensitivity to these dianhydrodulcitol doses in the same degree in germfree as in conventional mice . A study of the lymphoid organs and the intestinal wall indicate that both in germfree and conventional mice the dianhydrodulcitol sensitivity increasing effect of the endotoxin preparation was due to its stimulation of the lymphoid system . The higher resistance of germfree mice to dianhydrodulcitol is ascribed to their lack of a normal intestinal flora. Acta Microbiol Hung, 1983, 30(3-4), 179 - 88 Possible causes of the loss of specific pBR322-Ad h 1 DNA recombinants following transfection; Palkonyay L et al.; Characteristics of pBR322/Ad h 1 DNA recombinants were studied which had been cloned using HindIII restriction endonuclease in a single "shot-gun" experiment . Both oxytetracycline and ampicillin resistance of the clones were found to be heterogeneous . Ad h 1 DNA fragments HindIII-A, and -C could be cloned only in combination with other fragments . Among the possible reasons of the loss of recombinants upon transfection the impairment of pBR322-specific gene functions by the inserts is discussed in addition to the increased tetracycline resistance, and the tertiary structure of recombinant DNA. J Cell Biochem, 1983, 22(2), 87 - 97 Transport of hemolysin by Escherichia coli; Hartlein M et al.; The hemolytic phenotype in Escherichia coli is determined by four genes . Two (hlyC and hlyA) determine the synthesis of a hemolytically active protein which is transported across the cytoplasmic membrane . The other two genes (hlyBa and hlyBb) encode two proteins which are located in the outer membrane and seem to form a specific transport system for hemolysin across the outer membrane . The primary product of gene hlyA is a protein (protein A) of 106,000 daltons which is nonhemolytic and which is not transported . No signal peptide can be recognized at its N-terminus . In the presence of the hlyC gene product (protein C), the 106,000-dalton protein is processed to the major proteolytic product of 58,000 daltons, which is hemolytically active and is transported across the cytoplasmic membrane . Several other proteolytic fragments of the 106,000-dalton protein are also generated . During the transport of the 58,000-dalton fragment (and possible other proteolytic fragments of hlyA gene product), the C protein remains in the cytoplasm . In the absence of hlyBa and hlyBb the entire hemolytic activity (mainly associated with the 58,000-dalton protein) is located in the periplasm: Studies on the location of hemolysin in hlyBa and hlyBb mutants suggest that the gene product of hlyBa (protein Ba) binds hemolysin and leads it through the outer membrane whereas the gene product of hlyBb (protein Bb) releases hemolysin from the outer membrane . This transport system is specific for E coli hemolysin . Other periplasmic enzymes of E coli and heterologous hemolysin (cereolysin) are not transported. Comp Immunol Microbiol Infect Dis, 1983, 6(4), 313 - 9 The effectiveness of inactivated vaccines applied parenterally to sows to control Escherichia coli diarrhea in piglets in an industrial fattening farm; Ciosek D et al.; Different vaccines against Escherichia coli diarrhea of piglets were applied parenterally in pregnant sows at an industrial fattening farm . The following vaccines were used: vaccine No . 1 with non-complete Freund's adjuvant . Tween 80 and Arlacel A, comprising O149:K91,K88; O139:K82; O8:K87,K88; O141:K85,K88; and O64:K? E . coli serotypes; vaccine No . 2 with paraffin oil instead of Freund's adjuvant, comprising the same E . coli serotypes as the vaccine No . 1; stable specific vaccine with 10% aluminum hydroxide, based on E . coli serotypes most frequently isolated from piglets which died at the farm (O149:K91,K88; O8:K87,K88; O20:K17; O64:K?); Gletvax K88 (Wellcome) and NOBI-VAC LT-K88 (Intervet International) . The number of piglets which died up to the moment of weaning in comparison to the number of born ones was considered as an indicator of acquired protection . It was found that the most effective in conferring protection against E . coli diarrhea were: vaccine No . 1 and NOBI-VAC . The differences in the mortality rate between piglets originating from sows vaccinated with these vaccines and those from unvaccinated ones were statistically significant (P less than 0.05) . No significant differences were noted between controls and animals vaccinated with the remaining vaccines. Arch Immunol Ther Exp (Warsz), 1983, 31(4), 541 - 53 Enzymatic method of incorporation of 125I into DNA; Gladek A et al.; DNA can be labeled with iodine in the reaction catalyzed with lactoperoxidase . Iodine is incorporated in cytosine similarly as in the chemical reaction . Iodination by means of the enzymatic method is faster than by means of the chemical method . The equilibrium state is still achieved after 10 minutes, during the enzymatic reaction, while during the chemical reaction it is achieved after 30 minutes . The preservation of the proper concentration of LP/DNA less than or equal to 0.075 . ensures the proper reaction rate and decreases "self-iodination" of the enzyme . Deviations from the optimum conditions of the enzymatic reaction cause the decrease of the iodine incorporation or the increase of degradation of nucleic acid . Labeled DNA (less than or equal to 10% ICl) slightly differs from non-labeled DNA . Labeling 10% cytosine in DNA causes the decrease of melting temperature of about 1 degree C . DNA labeled this way reassociates with homologous non-labeled DNA at approximately 98%. IARC Sci Publ, 1983, (51), 141 - 6 Sex differences in in-vitro activation and in-vivo carcinogenicity; Matsushima T et al.; Metabolic activation capacities of liver from rats of both sexes were studied in a bacterial mutation test containing an in-vitro metabolic activation system . Livers of male Wistar rats had higher metabolic activity than those of females for the oesophageal carcinogens, N-nitrosomethylbenzylamine and N-nitrosomethylamylamine . Castration of and/or injection of oestradiol to male rats decreased the metabolic activation capacity of their livers towards these oesophageal carcinogens to the level seen in females . Neither castration nor injection of testosterone to female rats had a significant effect on the metabolic activation capacity of their livers; however, injection of testosterone to castrated females increased the metabolic activation capacity to that of male liver . Liver from male rats also had higher in-vitro metabolic activation capacities for N-nitrosodimethylamine and N-nitrosodiethylamine than that of females. Folia Microbiol (Praha), 1983, 28(6), 441 - 5 Stability of the hybrid plasmid pIM138 and its curing by some eliminating agents; Brana H et al.; Hybrid plasmid pIM138 was constructed by insertion of a chromosomal fragment with the threonine operon from Escherichia coli into the pBR322 vector . Molar mass of pIM138 was 2.8 Mg/mol . Heteroduplexes between pBR322 vector and pIM138 hybrid DNA molecules were prepared . The hybrid plasmid shows a high stability against the curing effect of rifampicin and clorobiocin in E . coli SK1590 thr host. EMBO J, 1983, 2(12), 2247 - 51 Binding of RecA protein to single-stranded nucleic acids: spectroscopic studies using fluorescent polynucleotides; Cazenave C et al.; Binding of the recA gene product from Escherichia coli to single-stranded polynucleotides has been investigated using poly(dA) that have been modified by chloroacetaldehyde to yield fluorescent 1,N6-ethenoadenine (epsilon A) bases . A strong enhancement of the fluorescent quantum yield of poly(d epsilon A) is induced upon RecA protein binding . A 4-fold increase is observed in the absence of ATP or ATP gamma S and a 7-fold increase in the presence of either nucleoside triphosphate . RecA protein can bind to poly(d epsilon A) in the absence of both Mg2+ ions and ATP (or ATP gamma S) but Mg2+ ions are required to observe RecA protein binding in the presence of ATP (or ATP gamma S) at pH 7.5 . ATP binding to the RecA-poly(d epsilon A) complex induces a dissociation of RecA from the polynucleotide followed by re-binding of {RecA-ATP-Mg2+} ternary complex . Whereas ATP-induced dissociation of RecA-poly(d epsilon A) complexes is a fast process, the subsequent binding reaction of {RecA-ATP-Mg2+} is slow . A model is proposed whereby {RecA-ATP-Mg2+} binding to poly(d epsilon A) involves slow nucleation and elongation processes along the polynucleotide backbone . The nucleation reaction is shown to involve at least a trimer or a tetramer . Polymerization of the {RecA-ATP-Mg2+} ternary complex stops when the polynucleotide is entirely covered with 6 +/- 1 nucleotides per RecA monomer . ATP hydrolysis then induces a release of RecA-ADP complexes from the polynucleotide template. EMBO J, 1983, 2(12), 2129 - 35 Characterization of two mutations in the Escherichia coli galE gene inactivating the second galactose operator and comparative studies of repressor binding; Fritz HJ et al.; A series of plasmids has been constructed which contain either a single one of the two operators O1 and O2 of the Escherichia coli galactose operon or different combinations thereof . This permits comparison of the two operators with respect to their repressor binding ability . A plasmid containing only the second operator, O2, located within the structural gene galE, was found to titrate repressor in vivo and in vitro with essentially the same efficiency as a plasmid containing only the 'classical' galactose operator, O1, located upstream of the start of transcription . Whereas some cooperativity between the two sites seems possible in vivo, they bind repressor independently under the conditions of the in vitro assay . After hydroxylamine treatment of plasmid DNA in vitro, two different mutations have been isolated each of which inactivates the second operator, O2 . Both are GC to AT transitions located at equivalent positions relative to the axis of rotational symmetry within the second gal operator . Subdividing O1 and O2 according to their 2-fold symmetry yields four half-sites with the consensus sequence (5')gTGnaAnC(3') . All known single point mutations of O1 and O2 affect the frame of invariant residues . The two half-sites of the lac operator also coincide with this frame. EMBO J, 1983, 2(12), 2117 - 22 Transitory recombination between plasmid pHV33 and phage M13; Dagert M et al.; Plasmid pHV33 and phage M13 which have no homology exceeding 13 bp, combine in Escherichia coli cells . The chimeric genome is encapsidated in phage proteins and injected into a recipient cell, where it decombines to regenerate the two parental genomes . We call this combination-decombination process 'transitory recombination'. Nucleic Acids Symp Ser, 1983, (12), 83 - 6 Chemical synthesis of a human fibroblast interferon gene and its expression in Escherichia coli; Nagase Y et al.; Using the solid phase phosphotriester method, a gene coding for human fibroblast interferon consisting of 166 amino acid residues was chemically synthesized . The gene obtained by ligation of 61 synthesized oligodeoxyribonucleotide fragments was inserted into the downstream of tryptophan promoter, and expressed in E . coli . Lysate of this E . coli showed the antiviral activity which was specifically neutralized by anti-fibroblast interferon antibody . No particular advantage was observed in the expression efficiency by the synthetic gene over that by the native gene. J Mol Appl Genet, 1983, 2(3), 261 - 71 Reconstitution of plant nitrate reductase by Escherichia coli extracts and the molecular cloning of the chlA gene of Escherichia coli K12; Taylor JL et al.; Extracts from Escherichia coli, wild type and chlB, chlC, chlD, chlE, and chlG, but not chlA mutants, were able to reconstitute the nitrate reductase activity in Nicotiana tabacum cnx68 and Hyoscyamus muticus MA-2 mutant extracts . Because cnx68 and MA-2 lack the molybdenum cofactor required for nitrate reductase activity, these results indicate that the functional chlA gene is essential to produce the molybdenum cofactor in E . coli . A clone containing a gene capable of complementing the chlA mutation SA493 was obtained on a large cosmid pJT1 . A 1.9 kb BclI fragment subcloned from pJT1 in the vector plasmid pBR322 was shown to complement the chlA SA493 mutant when inserted in either of the two possible orientations . This suggested that the chlA gene was contained intact, including its own promoter, on the 1.9 kb BclI fragment. Circ Shock, 1983, 11(4), 341 - 50 Antidipsogenic effect of endotoxin in the rat; Foca A et al.; Escherichia coli LPS (640-1280 mcg/Kg, intravenously) showed a powerful, dose-dependent and long-lasting inhibitory effect on drinking behavior stimulated by 48 h water deprivation, subcutaneous injection of isoprenaline (33.3 mcg/Kg) and intracerebroventricular injection of hypertonic NaCl (2.9%) solution, carbachol (250 ng) and angiotensin II (100 ng) . The antidipsogenic effect was neither a consequence of behavioral alterations, nor due to endotoxin peripheral vasodilating activity . Naloxone (60-120-240 mcg/Kg, subcutaneously) did not influence endotoxin inhibition of water intake, thus ruling out an endorphin-mediated effect . When prostaglandin synthesis was inhibited, the effect of endotoxin was reduced . Since prostaglandins do not seem to be involved in the regulation of thirst, the mechanism of the antidipsogenic effect elicited by endotoxin needs further study. Circ Shock, 1983, 11(4), 311 - 8 Metabolic clearance rate of ketone bodies in dogs following Escherichia coli endotoxin administration; Romanosky AJ et al.; The metabolic clearance rates of ketone bodies were determined in anesthetized dogs following the intravenous administration of either Escherichia coli endotoxin or saline, in order to examine the influence of endotoxin on the efficiency of peripheral ketone body removal . A nonisotopic method was employed for these studies consisting of a stepwise infusion of beta-hydroxybutyrate at three different rates . At each infusion rate, a steady-state arterial concentration was reached, at which time the rate of appearance of ketone bodies equaled their removal rates . Rates of infusion were plotted against the steady-state arterial concentrations, and the reciprocal of the slope of this linear relationship represented the metabolic clearance rate . Administration of endotoxin did not alter the metabolic clearance rate of ketone bodies . The uptake of ketone bodies by the thigh muscles was also unaffected by endotoxin administration . It is concluded, that E . coli endotoxin does not influence the efficiency of peripheral ketone body removal. Circ Shock, 1983, 11(4), 287 - 95 Increased glucose uptake precedes hyperinsulinemia in awake endotoxemic minipigs; Hand MS et al.; The role of hyperinsulinemia in the development of hypoglycemia was evaluated in awake Yucatan minipigs . Eight adult minipigs were fitted with jugular, portal, and hepatic vein and carotid artery catheters, and hepatic artery and portal vein flow cuffs for determination of transhepatic kinetics and insulin secretion . Three days later they were infused with E . coli endotoxin at 15 micrograms/kg/hr . Transient hyperinsulinemia was preceded by an elevation of the rate of glucose uptake (Rd) determined from {6-3H} glucose-specific activity . This finding suggested that hyperinsulinemia might be caused by, and then be contributory to, increased Rd . If an increase in glucose uptake was also experienced by pancreatic beta-cells, the existing glycemic state could be overestimated and an inappropriate insulin release elicited. Cancer Immunol Immunother, 1983, 16(2), 123 - 6 Effect of interferon on human neutrophilic granulocytes; Jarstrand C et al.; The in vitro influence of interferon (IFN) on various functions of human neutrophilic granulocytes was investigated . It was observed that the attachment and engulfment of opsonized yeast particles by human neutrophilic granulocytes were enhanced after preincubation in vitro with IFN for 30 min . The same result was obtained whether the particles were opsonized with fresh normal serum (complement) or with specific antibodies . However, after incubation of the granulocytes with IFN for 3 h the phagocytosis rate was somewhat decreased . Nitroblue tetrazolium (NBT) reduction by resting granulocytes was slightly, although not significantly, increased by preincubation with IFN for 30 min, but their NBT reduction during phagocytosis of E . coli was significantly increased . No major effects of preincubation with IFN were observed on spontaneous or random migration of granulocytes. Ann Rech Vet, 1983, 14(3), 207 - 10 Escherichia coli isolated from calves with diarrhea: mannose-resistant haemagglutination and colonisation factor; Valente C et al.; A study was carried out for detection of the adhesive antigen K99 on 84 Escherichia coli strains isolated from calves with diarrhea . The methods utilized were the Brush-Border and the slide agglutination tests; the strains were also tested in their ability to evoke mannose-resistant haemagglutination . The positive results obtained with the slide agglutination test were higher with comparison to the positive results obtained with other tests . The bacteria had the other piliated structures, besides the K99 antigen, that require further studies. Acta Microbiol Hung, 1983, 30(1), 13 - 7 Stimulation of human peripheral lymphocytes with endotoxin and radiodetoxified endotoxin; Temesi A et al.; The effects of parent endotoxin and radiodetoxified endotoxin on human peripheral lymphocytes were compared in experiments in vitro . Radiodetoxified endotoxin is able to exceed the degree of the stimulation induced by parent endotoxin and its stimulatory effect . At the same time, no change was observed in the presence of autologous serum . Radiodetoxified endotoxin did not inhibit the phytohaemagglutinin-induced proliferative response. Vet Med Nauki, 1983, 20(7), 3 - 8 {Prevention of colibacillosis in pigs with CA-80 polyvalent vaccine}; Boiadzhiev S et al.; A live polyvalent Escherichia coli vaccine, CA-80, has been produced and adopted into practice in this country . It contains a definite amount of immunogenic agents, such as the K 88 antigen, the LT and ST toxins, the K 99 antigen, and an enteroinvasive strain . Laboratory and field experiments have shown that the immunization of sows with newborn sucking pigs leads to the drop of mortality rate from 8.48 to 1.84 per cent as well as to the rise of the average liveweight by 400 to 600 g on the 30th day following birth . Besides, the live vaccine has been shown to act protectively both against the homologous and heterologous enterotoxigenic strains of Escherichia coli and against E . coli strains with a K 99 antigen. Vet Med Nauki, 1983, 20(7), 17 - 21 {Hematological studies of colibacillosis in pigs}; Dobrev V et al.; Four-year hematologic studies were carried out with a total of 51 spontaneously and experimentally infected pigs that developed colibacteriosis . In both cases there were hypochromic anemia, lymphocytosis, and basophilia, and in some of the animals there were hypersegmentation of the nucleus with toxic granulocytes . There were also differences concerning the hematologic indices with the use of individual Escherichia coli strains . They were most pronounced in pigs that were infected with strain O149 and strain 1257 (Poland) . Sows that were treated with a killed colibacteriosis vaccine showed no changes in the hematologic profile. Trans R Soc Trop Med Hyg, 1983, 77(5), 702 - 6 The prevalence and intensity of Ascaris lumbricoides infections in Moslem children from northern Bangladesh; Martin J et al.; The results are presented of a horizontal epidemiological survey of intestinal infections of children aged between six months and 15 years in three adjacent villages in northern Bangladesh . On the basis of 203 stool sample examinations, the prevalence of Ascaris lumbricoides, Trichuris trichiura, hookworm and amoebic infections was estimated as 68, 56, 53 and 19%, respectively . Age-specific prevalence data indicated that approximately 90% of the children were harbouring patent Ascaris infections by the time they were four years old and there was some evidence to suggest differences in the pattern of age-prevalence between male and female children . The intensity of Ascaris infection was found to rise to its maximum value within the first four years of life . No significant differences were detected in the mean worm burdens of children aged between four and 15 years . Each child in this age-group harboured on average 10 worms . The frequency distribution of numbers of A . lumbricoides per host was found to be overdispersed, with a value of the negative binomial parameter, k, of 0.44 . The degree of aggregation was found to be approximately the same for each age-class of the population between one and 15 years (0.26 less than or equal to k less than or equal to 0.82) . No evidence was found to suggest a density-dependent reduction in the weight of either male or female Ascaris within the range one to 43 worms per host.(ABSTRACT TRUNCATED AT 250 WORDS) Prog Food Nutr Sci, 1983, 7(3-4), 193 - 205 The clinical manifestation and pathogenesis of enteritis associated with rotavirus and enterotoxigenic Escherichia coli infections in domestic animals; Tzipori S et al.; Rotavirus and enterotoxigenic Escherichia coli (ETEC) are enteropathogens each capable of inducing diarrhoea in some animal species and man . Unstressed young animals develop an age-related resistance to infection with either rotavirus or ETEC which differs for each animal species . The effects of experimental infection of calves, lambs, foals and piglets with rotavirus and ETEC given either alone or in combination, have been examined . In general, dual infections tended to lengthen the period of age susceptibility and increase the severity of gastroenteritis, compared to infection with either agent alone . ETEC caused little or no pathological changes in the small intestine while rotavirus induced moderate inflammatory, morphological and physiological changes including reduced activity of membrane-bound digestive enzymes . In dual infections, mucosal lesions were more severe than those seen after rotavirus infection and ETEC proliferation in the lumen of the small intestine was greater than in animals infected with ETEC alone . Two distinct mechanisms of diarrhoea, presumably, were involved; net fluid hypersecretion into the lumen of the gut mediated by ETEC enterotoxin(s), and brush border maldigestion and malabsorption which was caused by rotavirus infection of the small intestine. Prog Food Nutr Sci, 1983, 7(3-4), 107 - 16 Intraspecific interactions between Escherichia coli strains in human newborns and in gnotobiotic mice and piglets; Duval-Iflah Y et al.; A plasmid-free human Escherichia coli strain EMO, was inoculated to human newborns within two hours of life . It became established in the feces at a high population level . Ampicillin and tetracycline resistant E . coli strains disappeared or decreased to subdominant level in the inoculated newborns whereas they remained at a high level in the noninoculated newborns . Strain EMO was also shown to exert a barrier effect against a porcine plasmid-bearing enterotoxigenic Ent+ K88- E . coli strain in gnotobiotic mice . Axenic piglets monoassociated with Ent+ K88- E . coli strain died within 6 days . Axenic piglets diassociated with both EMO and the Ent+ E . coli survived longer, though no significant difference was observed between the population level of the Ent+ E . coli in the mono- and diassociated piglet feces . These results suggest that a prior inoculation with a non-pathogenic E . coli strain may improve the spontaneous ecological protection of piglets against Ent+ E . coli strains. Mol Gen Genet, 1983, 192(3), 506 - 8 Increased expression of the dnaA gene has no effect on DNA replication in a dnaA+ strain of Escherichia coli; Churchward G et al.; We have constructed a pBR322 plasmid derivative which expresses dnaA protein under the control of the E . coli lac UV5 promotor . Expression of the dnaA protein from the plasmid is inducible by isopropyl-beta-D-thiogalactoside . In a dnaA+ strain induction has no effect on the accumulation of DNA . In contrast, in a thermosensitive dnaA46 strain, induction, at either the permissive or the nonpermissive temperature, results in an immediate stimulation of DNA accumulation . We conclude that, while in a dnaA46 strain dnaA protein limits DNA replication, in a dnaA+ strain dnaA protein activity does not control the timing of replication initiation. Mol Gen Genet, 1983, 192(3), 391 - 4 recA+ gene-dependent regulation of a uvrD::lacZ fusion in Escherichia coli K12; Nakayama K et al.; The expression of the Escherichia coli uvrD gene was studied with a uvrD::Mud(Aprlac) insertion mutant . The results indicate that it is inducible by DNA damaging agents in a recA+ gene-dependent manner. Mol Gen Genet, 1983, 192(3), 366 - 72 Site-specific recombination following conjugation in Escherichia coli K-12; Birge EA; In accord with the observations of other workers, unselected marker analysis of Escherichia coli K-12 transconjugants isolated from matings involving several different Hfr strains as donors has shown that most genetic exchanges are clustered either near the selected marker or near the origin of the transferred Hfr DNA . The present work increases the number of Hfr strains tested and shows that the clustering of the recombinational events near the origin of transfer is statistically significant . It is proposed that this clustering of genetic exchanges is due to the action of a unique recombination system (site-specific conjugal recombination or ssr) which recognizes the early transferred portion of the F plasmid and catalyzes a genetic exchange in or near the adjacent bacterial DNA . Twelve Hfr strains representing eleven different points of origin were tested, and only KL16 and Ra-1 did not demonstrate the typical clustering of genetic exchanges . Since these strains share a common transfer origin, they may represent spontaneous mutations affecting the ssr system. Mol Gen Genet, 1983, 192(3), 301 - 8 Immunological studies of Escherichia coli mutants lacking one or two ribosomal proteins; Dabbs ER et al.; A battery of immunological tests were used to investigate mutants which had been determined as lacking one or two ribosomal proteins on the basis of two-dimensional polyacrylamide gels . Proteins which were confirmed as missing from the ribosome in one or more mutants were large subunit proteins L1, L15, L19, L24, L27, L28, L30 and L33 and small subunit proteins S1, S9, S17 and S20 . Cross-reacting material (CRM) was also absent from the post-ribosomal supernatant except in the case of protein S1 . Since mutants lacking protein L11 have been previously described, any one of 13 of the 52 ribosomal proteins can be missing . None of these 13 proteins, except S1, can therefore have an indispensable role in ribosome function or assembly . In several mutants in which a protein was not missing but altered, it was present as several moieties of differing charge and size. J Mol Evol, 1983, 19(6), 429 - 36 Experimental evolution of a novel pathway for glycerol dissimilation in Escherichia coli; Jin RZ et al.; Wild-type Escherichia coli utilizes glycerol aerobically through an inducible pathway mediated by an ATP-dependent kinase and a glycerol 3-phosphate dehydrogenase which is a flavoprotein . A mutant, strain ECL424, employing a novel pathway for glycerol utilization was isolated . The novel pathway is mediated by an NAD-linked dehydrogenase and a dihydroxyacetone specific enzyme II of the phosphoenolpyruvate phosphotransferase system . This study describes the selection from strain ECL424, a derivative which grows more rapidly on glycerol . The derivative, strain ECL428, produces twice the parental levels of both the dehydrogenase and the enzyme II during growth on glycerol . The function of the dehydrogenase in wild-type cells is unknown, although hydroxyacetone (acetol), 3-hydroxy-2-butanone (acetoin), and 1-amino-2-propanone are gratuitous inducers . The induction can be prevented by glucose whose effect can be cancelled by external cyclic AMP . The effects of hydroxyacetone, glucose, and cyclic AMP are attenuated in the two mutants in which the dehydrogenase is produced at high basal levels . The dihydroxyacetone specific enzyme II is inducible by the substrate in both wild-type and mutant strains and serves for growth on the triose. J Mol Evol, 1983, 19(6), 420 - 8 tRNA-rRNA sequence homologies: evidence for a common evolutionary origin? Bloch DP, McArthur B, Widdowson R, Spector D, Guimaraes RC, Smith J. Many tRNAs of E . coli and yeast contain stretches whose base sequences are similar to those found in their respective rRNAs . The matches are too frequent and extensive to be attributed to coincidence . They are distributed without discernible pattern along and among the RNAs and between the two species . They occur in loops as well as in stems, among both conserved and non-conserved regions . Their distributions suggest that they reflect common ancestral origins rather than common functions, and that they represent true homologies. Intensive Care Med, 1983, 9(6), 345 - 7 Paratracheal abscess after tracheostomy; Cole AG et al.; Mediastinal abscess formation in the paratracheal region is a complication of tracheostomy that has previously been only sparsely reported . We present a case which highlights this complication and illustrates some of the diagnostic difficulties with which it may be associated . In this case septicaemia-developed as a secondary complication and diagnosis of the abscess was dangerously delayed because the radiographic appearance masqueraded as a left upper lobe consolidation and because its rarity led to a low index of suspicion. Clin Lab Haematol, 1983, 5(3), 259 - 63 Massive retroperitoneal lymphadenopathy as a terminal event in hairy cell leukaemia; Mehta AB et al.; A case of hairy cell leukaemia complicated as a terminal event by massive retroperitoneal lymphadenopathy is described . The patient had recently been treated with lithium carbonate and had previously been demonstrated to suffer from a systemic vasculitis, either or both of which may have contributed to the development of this rare complication. Toxicon, 1983, 21(5), 717 - 27 Calcium accumulation in human and sheep erythrocytes that is induced by Escherichia coli hemolysin; Jorgensen SE et al.; The membrane permeability of both human and sheep erythrocytes is modified by an Escherichia coli-produced extracellular hemolysin . Alterations in membrane permeability were determined by measuring changes in the extracellular concentration of radiolabeled compounds that had been added to a 30-35% erythrocyte suspension . During the pre-lytic period, the E . coli hemolysin promotes calcium accumulation by both human and sheep erythrocytes . The concentration of calcium associated with the cells rises to a level that is approximately 1.5 (sheep) to 3 (human) times higher than that in a comparable volume of extracellular solution . Hemolysin also causes a rapid depletion of the high intracellular potassium levels normally present in human erythrocytes . That neither inulin, sucrose nor phosphate is accumulated by hemolysin-treated erythrocytes indicates that hemolysin makes the membrane selectively permeable to cations. Radiat Environ Biophys, 1983, 22(3), 215 - 23 Role of glutathione in affecting the radiosensitivity of molecular and cellular systems; Simone G et al.; It has previously been shown that radioinduced organic radicals can be repaired by hydrogen donation from glutathione (GSH) and this repair is in competition with oxygen (damage fixation) . In this paper the influence of exogenous glutathione on the radiation response of the enzyme alcohol dehydrogenase (YADH), DNA in vitro, and E . coli B/r cells has been investigated . GSH is observed to protect YADH essentially by free radical scavenging mechanisms in both presence or absence of oxygen . The same mechanism seems operate in the radioprotection afforded by GSH to DNA in vitro . E . coli B/r cells are protected at higher extent by GSH than its oxidized form (GSSG); the possibility that GSH penetrate into bacterial cells more easily that GSSG can explain their different behaviour . None of the three systems studied has provided definitive support for the occurrence of the hydrogen donation reaction in the radioprotective mechanisms of GSH versus biomolecules and bacterial cells. Med Microbiol Immunol (Berl), 1983, 172(3), 165 - 9 Enterotoxigenic and enteropathogenic Escherichia coli in Galicia (north-west Spain); Blanco J et al.; We have studied the incidence of enterotoxigenic and enteropathogenic Escherichia coli strains associated with infant diarrhoeal disease in Galicia (North-west Spain) . During a period of 9 months we isolated heat-labile enterotoxin-positive strains in 2.1% of children with diarrhoea examined, whereas the production of heat-stable enterotoxin was detected in 1.1% of them . Enteropathogenic strains were isolated from 5.3% of the children with diarrhoea, but none of these strains released heat-labile or heat-stable enterotoxins. Mol Gen Genet, 1983, 192(1-2), 80 - 6 The dnaX gene encodes the DNA polymerase III holoenzyme tau subunit, precursor of the gamma subunit, the dnaZ gene product; Kodaira M et al.; The E . coli dnaX and dnaZ gene products, essential for E . coli DNA replication, serve in chain elongation . Both genes, located at 10.4 min and previously cloned into a lambda vector and a ColE1 plasmid, were subcloned into pBR322 (pMK212) . The coding region for the dnaX and dnaZ genes was localized to a 2.2-kb segment by deletion analysis of pMK212 . The products of dnaX and dnaZ genes were identified as 78 kd and 52 kd polypeptides, respectively, by using maxicells bearing deletion clones of pMK212 . Peptide mapping after limited proteolysis showed that the dnaZ gene product (52 kd) is a part of the dnaX gene product (78 kd), thus accounting for the coding capacity of the 2.2 kb region for both the dnaX and dnaZ genes . The dnaX gene product appears to be the tau subunit of DNA polymerase III holoenzyme; the dnaZ gene product is confirmed as the gamma subunit of the holoenzyme. Mol Gen Genet, 1983, 192(1-2), 32 - 8 A comparison of the origin of replication of pSa with R6K; Tait RC et al.; The plasmid pOri3 is a derivative of the origin of replication of pSa . Replication is defective as a result of a truncated repA gene, the product of which is required for plasmid replication . The defective replication is complemented by the presence of the intact repA gene of pSa, or by the presence of the plasmid R6K . The basis of this complementation has been examined by comparing the nucleotide sequence of the origin of pSa with that of R6K . A 13 base pair sequence present twice in the origin of pSa has homology with a 13 base pair sequence that is present fourteen times in the origin of R6K . These sequences may be the binding sites for the initiator proteins of these two plasmids . The location of these binding sites relative to the genes for the initiator proteins suggests that an autoregulatory control mechanism for the synthesis of the initiator proteins may also play a role in the control of plasmid copy number. Mol Gen Genet, 1983, 192(1-2), 282 - 4 Evidence that the phr+ gene enhances the ultraviolet resistance of Escherichia coli recA strains in the dark; Yamamoto K et al.; An Escherichia coli recA phr+ purA strain was more resistant to ultraviolet radiation than its isogenic derivative recA phr+ purA+ in the absence of photoreactivating light, whereas their nearly isogenic derivative recA phr showed most UV-induced lethality . The amounts of photoreactivating enzyme (PRE) per cell in the recA phr+ purA was higher than in the recA phr+ purA+ . The recA phr is defective for photoreactivation . Thus, in the recA strain, UV resistance in the dark increased in proportion to the amounts of PRE per cell, suggesting that PRE participates in the process of dark repair of UV-damaged DNA. Mol Gen Genet, 1983, 192(1-2), 15 - 20 Escherichia coli K12 mutants defective in the glycine cleavage enzyme system; Plamann MD et al.; Two routes of one-carbon biosynthesis have been described in Escherichia coli K12 . One is from serine via the serine hydroxymethyltransferase (SHMT) reaction, and the other is from glycine via the glycine cleavage (GCV) enzyme system . To isolate mutants deficient in the GCV pathway, we used a selection procedure that is based on the assumption that loss of this enzyme system in strains blocked in serine biosynthesis results in their inability to use glycine as a serine source . Mutants were accordingly isolated that grow with a serine supplement, but not with a glycine supplement . Enzyme assays demonstrated that three independently isolated mutants have no detectable GCV enzyme activity . The absence of a functional GCV pathway results in the excretion of glycine, but has no affect on the cell's primary source of one-carbon units, the SHMT reaction . The new mutations, designated gcv, were mapped between the serA and lysA genes on the E . coli chromosome. Folia Microbiol (Praha), 1983, 28(5), 345 - 52 Isolation and characterization of a higher-copy-number mutant of plasmid R6K; Nesvera J et al.; A stable copy-number mutant (pNH601) of plasmid R6K was isolated by selection for increased resistance to ampicillin determined by this plasmid . The size of the mutant plasmid was found to be unchanged (26 Mg/mol) but it is present in 27 copies of pNH601 per E . coli K-12 chromosome which represents a two-fold increase of R6K copy number value . The following genetic properties of pNH601 are reported and compared with those of R6K: conjugative transfer, fertility inhibition of plasmids belonging to other incompatibility groups, incompatibility with plasmid R485 under both non-selective and selective conditions and the integrative suppression of the dnaA ts mutation . The mutant plasmid pNH601 was found to be different from the original R6K in most of these properties. EMBO J, 1983, 2(6), 899 - 905 The nucleotide sequence of an Escherichia coli operon containing genes for the tRNA(m1G)methyltransferase, the ribosomal proteins S16 and L19 and a 21-K polypeptide; Bystrom AS et al.; The nucleotide sequence of a 4.6-kb SalI-EcoRI DNA fragment including the trmD operon, located at min 56 on the Escherichia coli K-12 chromosome, has been determined . The trmD operon encodes four polypeptides: ribosomal protein S16 (rpsP), 21-K polypeptide (unknown function), tRNA-(m1G)methyltransferase (trmD) and ribosomal protein L19 (rplS), in that order . In addition, the 4.6-kb DNA fragment encodes a 48-K and a 16-K polypeptide of unknown functions which are not part of the trmD operon . The mol . wt . of tRNA(m1G)methyltransferase determined from the DNA sequence is 28 424 . The probable locations of promoter and terminator of the trmD operon are suggested . The translational start of the trmD gene was deduced from the known NH2-terminal amino acid sequence of the purified enzyme . The intercistronic regions in the operon vary from 9 to 40 nucleotides, supporting the earlier conclusion that the four genes are co-transcribed, starting at the major promoter in front of the rpsP gene . Since it is known that ribosomal proteins are present at 8000 molecules/genome and the tRNA-(m1G)methyltransferase at only approximately 80 molecules/genome in a glucose minimal culture, some powerful regulatory device must exist in this operon to maintain this non-coordinate expression . The codon usage of the two ribosomal protein genes is similar to that of other ribosomal protein genes, i.e., high preference for the most abundant tRNA isoaccepting species . The trmD gene has a codon usage typical for a protein made in low amount in accordance with the low number of tRNA-(m1G)methyltransferase molecules found in the cell. EMBO J, 1983, 2(5), 791 - 7 Regulation of adenylate cyclase synthesis in Escherichia coli: nucleotide sequence of the control region; Roy A et al.; The regulatory region of the cya gene from Escherichia coli has been characterized by nucleotide sequence analysis and genetic approaches . Two promoters, P1 and P2, organized in that order with respect to the beginning of the cya open reading frame, were identified . Using cya-lac operon and protein fusions, it was possible to show that both promoters are active in vivo . P1 activity seemed sensitive to catabolite repression whereas activity of the stronger promoter, P2, did not respond to inhibition by glucose . No effect of cAMP or its receptor, catabolite activator protein (CAP), could be found although the DNA sequence reveals a consensus CAP site downstream of P2 . The 548 nucleotides situated at the 3' end of the sequence carry an open reading frame which can tentatively be assigned to the beginning of adenylate cyclase . Among noteworthy features of the corresponding sequence are an UUG codon as the putative start site of cyclase, and a long hydrophobic stretch of amino acids resembling leader peptides in secreted or membrane proteins. Circ Shock, 1983, 11(2), 85 - 99 Cellular effects of endotoxin in vitro . I . Effect of endotoxin on mitochondrial substrate metabolism and intracellular calcium; Kilpatrick-Smith L et al.; Intramitochondrial substrate metabolism was examined in cultured neuroblastoma NB41A3 cells exposed to endotoxin in order to elucidate possible causes for the changes in {ATP}/{ADP}{Pi} and {NAD+}/{NADH} reported by us previously in these cells {1} . Flux through pyruvate dehydrogenase (PDH), measured with {1-14C}-pyruvate, was inhibited by 54% within 10 min in endotoxin-treated cells (0.99 nmol/min/mg dry wt vs 0.46 nmol/min/mg dry wt) . In contrast, flux through 2-oxoglutarate dehydrogenase, measured with {1-14C}-glutamate was unaltered (0.79 nmol/min/mg dry wt) . Dichloroacetate, an inhibitor of PDH kinase, restored flux through PDH to control levels . In endotoxin-treated cells, only 44% of the total PDH complex was in the active (nonphosphorylated) form as compared to 72% in control cells . Equilibrium uptake studies with 45Ca2+ and atomic absorption measurements showed that intracellular {Ca2+} in endotoxin-treated cells was about 20% lower than in control cells . It is postulated that binding of endotoxin to the plasma membrane triggers a sequence of events that lead to an initial decline in intracellular calcium concentration and that this latter event may be responsible for the inhibition of PDH phosphatase and consequent conversion of the complex to its inactive phosphorylated form. Circ Shock, 1983, 11(2), 101 - 11 Cellular effects of endotoxin in vitro . II . Reversibility of endotoxic damage; Kilpatrick-Smith L et al.; Administration of Escherichia coli endotoxin to NB41A3 neuroblastoma cells in culture produced decreases in 1) intracellular {ATP}/{ADP}, 2) flux through pyruvate dehydrogenase (PDH), and 3) total intracellular calcium . These effects were reversible if endotoxin was washed off within 10-15 min, but not if it remained in contact with the cells for 30 min or more . Minor, reversible morphological and functional alterations occurred during the initial phase, but after 30-min exposure to the toxin, the damage was irreversible . A model is proposed in which early, reversible weak binding of endotoxin to the plasma membrane partially blocks inward calcium flux, lowering the intracellular {Ca2+} and consequently the PDH phosphatase activity which activates the PDH complex . If endotoxin is removed at this stage, these processes are reversed and the cell recovers . If not, the toxin becomes irreversibly incorporated into the cell with consequent damage to the plasma membrane and organelles, which leads to massive ion movements resulting in cellular hydration with ultimate disruption of mitochondria and cell death. Biol Neonate, 1983, 44(5), 309 - 14 Metabolic and hormonal response to endotoxin fever in fed and starved one-week rabbits; Molnar D et al.; The metabolic and hormonal effect of Escherichia coli endotoxin injected intraperitoneally was studied in fed and starved rabbits aged 6-9 days . Fed rabbits responded to endotoxin with fever, starved animals became hypothermic . Endotoxin caused a transient rise in blood glucose in both groups which was associated with a rise in plasma insulin concentration . Blood glycerol levels fell only in starved rabbits, and hydroxybutyrate concentration in both groups following endotoxin treatment . No change in blood pyruvate, lactate, alanine, or acetoacetate level was observed in either group. Acta Radiol Diagn (Stockh), 1983, 24(4), 305 - 8 Pneumopyopericardium; Stridbeck H et al.; Pneumopyopericardium is a rare disease, the etiology of which can be traumatic or non-traumatic . Today the most common cause of non-traumatic disease seems to be ulceration or carcinoma in the lower esophagus or upper stomach . The present cases were caused by ulcerations in two patients and a postoperative penetrating abscess in the third . All had connections with surgery in the region . Chest radiography disclosing fluid and gas in the expanded pericardium was the main diagnostic method . The prognosis is poor and all three patients died. Prep Biochem, 1983, 13(3), 245 - 60 Improved method for purification of human Escherichia coli heat-stable enterotoxin by hydrophobic interaction, molecular-sieve and high performance ion exchange chromatography; Ronnberg B et al.; A heat-stable enterotoxin produced by human enterotoxigenic Escherichia coli has been purified to homogeneity by hydrophobic interaction, molecular-sieve and high performance liquid chromatography with a recovery of 48% . The toxin is composed of 10 different amino acids with a total of 18 amino acid residues, one-third of which are half-cystine . Purified enterotoxin contains no carbohydrate and is biologically active in the suckling mouse test in 2.1-ng quantities . The molecule was heat-stable (80 degrees C, 20 min.) at pH 7 and pH 2 but lost biological activity at pH 12 . Biological activity was lost when treated with the reducing agent dithiothreitol, suggesting that the presence of disulfide bridges is required for biological activity. Mol Gen Genet, 1983, 191(3), 466 - 72 Molecular cloning of a gene which regulates the adaptive response to alkylating agents in Escherichia coli; Sedgwick B; The ada+ gene of E . coli is a regulatory gene of the adaptive response to simple alkylating agents . ada mutants are sensitive to both the mutagenicity and toxicity of alkylating agents, and are unable to induce O6-methylguanine DNA methyltransferase and 3-methyladenine DNA glycosylase II . The ada+ gene was cloned from wild type E . coli B by ligating bacterial DNA partially digested with Sau3A into the cosmid vector pJB8 . The hybrid cosmid, pCS33, conveyed N-methyl-N'-nitro-N-nitrosoguanidine resistance to ada mutants of E . coli B and E . coli K12, and resulted in the constitutive synthesis of the two DNA repair enzymes at high levels . An alk mutation, which results in a deficiency of only the DNA glycosylase, was not complemented by this cosmid . It was concluded that the product of the ada+ gene is a positive regulator of the adaptive response . The cosmid insert DNA was subcloned into the plasmid vector pAT153, and the ada+ plasmids pCS42 and pCS58 selected . The ada+ gene was located in pCS58 by transposon mutagenesis and subcloning . Two polypeptides of Mr 37,000 and 27,000, were identified in 'maxi-cells' as products of the ada+ gene(s) . It is as yet unclear whether they represent different forms of the same gene product, or are encoded by separate ada+ genes within the same operon. Mol Gen Genet, 1983, 191(3), 421 - 6 Cloning and expression of R-factor mediated arsenate resistance in Escherichia coli; Mobley HL et al.; The resistance transfer factor R773 confers inducible arsenate, arsenite and antimony resistance on Escherichia coli . The genes for these resistances were cloned into the EcoRI site of plasmid pBR322 to produce a 33 kilobase plasmid . pUM1 . Bacterial strains transformed with pUM1 synthesized a polypeptide of the apparent molecular weight 64,000 daltons when induced with arsenite . This polypeptide could be visualized on sodium dodecyl sulfate polyacrylamide gels stained with Coomassie blue . It was observed both in the membrane and cytosol fractions but not among the periplasmic proteins present in osmotic shock fluid . Minicells isolated from strain JR410(pUM1) incorporated {35S}methionine into an inducible 64,000 dalton polypeptide, as demonstrated on autoradiographs of electrophoresed {35S}-labeled minicell lysates, confirming that this polypeptide is a plasmid gene product . A 4.3 kilobase HindIII fragment of pUM1 was subcloned into the HindIII site of pBR322, producing recombinant plasmid pUM3 . This plasmid conferred constitutive resistance ot arsenite and arsenate . Extensive synthesis of two polypeptides of 64,000 and 16,000 daltons was observed both in Coomassie stained gels of whole cells and autoradiographs of gels of {35S}methionine-labeled minicells . Synthesis of both polypeptides was constitutive. Mol Gen Genet, 1983, 191(3), 397 - 400 The Escherichia coli uvrD gene is inducible by DNA damage; Siegel EC; The product of the uvrD gene of Escherichia coli is involved in the repair of DNA damage, mismatch repair, and recombination . Phage Mud(Amp, Lac) was used to form a uvrD-lacZ fusion allowing uvrD expression to be followed by measuring the activity of beta-galactosidase, the product of the lacZ gene . uvrD expression was inducible by DNA damage and was under the control of lexA-recA regulatory system . Mutations in the uvrD gene that result in different phenotypes in respect to DNA repair and spontaneous mutation have been previously found . The phenotype of the uvrD::Mud(Amp, Lac) mutant was mutator and UV-sensitive but not as deficient in host cell reactivation or repair of methyl methanesulfonate damage as the previously described uvrD3 mutant. Mol Gen Genet, 1983, 191(3), 389 - 92 Incorporation of thymine-containing DNA precursors in plasmolysed cells infected by the T4 non-lethal recombination defective mutants; Melamede RJ et al.; Incorporation of TdR is aberrant in cells plasmolysed 15 min after infection by the recombination defective t4 chi and omega mutants . The in situ results parallel those obtained in vivo: at high TdR concentrations both T4 chi and T4 omega induced incorporation is slightly reduced compared to wild type, whereas at low TdR concentration incorporation induced by T4 chi is reduced and that induced by T4 omega is increased compared to wild type . No differences between wild type and mutant induced TdR incorporation are observed when cells are plasmolysed 8 min after infection . Further, no difference in incorporation between wild type and T4 chi or T4 omega is observed when either 3H thymine or 3H dTTP is used as a substrate, however small incorporation differences are observed using 3H dTMP as substrate . The mitomycin C sensitivity of T4 chi induced TdR incorporation is also observed in situ, but the drug must be present throughout infection . T4tk omega mutants have increased ability to incorporate 1 microM 3H TdR compared to T4tk and the reduced incorporation of 1 microM 3H TdR by T4 chi is suppressed in a T4td chi double mutant . These data are compatible with the hypothesis that endogenously produced TdR modulates leading and lagging strand synthesis and that the aberrant 1 microM TdR incorporation exhibited by T4 chi and T4 omega reflects specific activity changes resulting from a recombination defect induced alteration of the TdR "modulator pool". Mol Gen Genet, 1983, 191(3), 382 - 8 Incorporation of thymine-containing DNA precursors in wild-type and mutant T4-infected plasmolysed cells; Melamede RJ et al.; T4-infected cells, plasmolysed 15 min after infection, incorporate low concentrations (less than 20 microM) of deoxythymidine (TdR) into DNA at a significantly greater rate than dTMP, dTTP or thymine . At higher concentrations (greater than 40 microM), dTMP incorporation rate is high, approaching that of TdR at 200 microM . TdR is selectively incorporated at all concentrations tested, and is not inhibited by the other thymine containing DNA precursors . Incorporation of low concentrations of TdR requires the T4-induced thymidine kinase (tk) and is not significantly affected by the presence or absence of T4-induced thymidylate synthetase (td) . We show that, in T4-infected plasmolysed cells, exogenously added TdR is preferentially incorporated into short DNA fragments during short pulse times . To explain these and other data a model is proposed in which thymidine plays a modulatory role between leading and lagging strand precursor feeds. Mol Gen Genet, 1983, 191(3), 378 - 81 Ram ribosomes are defective proofreaders; Andersson DI et al.; We have studied the kinetics of poly(U) translation by three ribosomal ambiguity (Ram) mutants in an in vitro system with performance characteristics similar to those expressed in vivo . The leucine missense frequency supported by Ram ribosomes with tRNALeu2 increases between six and twelve-fold over that of wild-type ribosomes, while the corresponding increase with tRNALeu4 was between four and eight-fold, depending on the rpsD allele . We have used a steady-state assay for proofreading to identify the kinetic lesion responsible for the Ram phenotype . We were unable to detect any difference between Ram and wild-type ribosomes with respect to the initial kinetics of amino-acyl tRNA selection . All of the increased error rates could be associated with a decreased capacity of these Ram ribosomes to discard non-cognate aminoacyl-tRNA by proof reading. Comp Immunol Microbiol Infect Dis, 1983, 6(3), 235 - 45 Fat globule membrane of sow milk as a target for adhesion of K88-positive Escherichia coli; Atroshi F et al.; Membrane adhesion of K88-positive Escherichia coli was studied on intestinal brush-border membranes on 237 Finnish Landrace pigs . Forty-one per cent of the brush-border membrane preparations aggregated E . coli (positive adhesion) . Similar dualism of adherence/nonadherence was observed on sow milk fat globule membranes . Washed milk fat globules (washed cream) can be used as a convenient source of material for adhesion studies . Bacterial adherence on to milk fat globules is evident as agglutination of the globules (dark-field microscopy) . By this procedure the sows can be typed according to their receptor phenotype . This simple principle of fat globule agglutination due to receptors for K88-positive E . coli might be complicated by SigA-mediated bacterial adherence . Fat globule membranes were shown to contain SigA, which may act as a mediator of bacterial adherence onto fat globules . The significance of this adhesive property of milk fat globule might be to provide alternative receptors for E . coli thus preventing bacterial adhesion on to gastro-intestinal epithelium of the offspring . Sow milk fat globules can be used for typing E . coli for membrane adhesiveness . The adhesiveness of the strains showed a good correlation with the presence of the K88 antigen, as well as the hydrophobicity of the bacterial strain as determined by an association on Phenyl-Sepharose beads. Arch Toxicol Suppl, 1983, 6, 333 - 8 A novel micromethod for the Limulus amebocyte lysate (LAL) assay for endotoxin, based on hydrostatic pressure; Neeman I et al.; A micromethod for performing the Limulus amebocyte lysate (LAL) assay for the presence of endotoxin is described which requires only about five percent of the standard amount of LAL reagent . The method is based upon measuring an increased amount of hydrostatic pressure required to cause a gelled LAL sample to flow from a capillary tube . The method is simple, rapid and correlates well with the results of the standard LAL assay procedure. Toxicon, 1983, 21(4), 553 - 7 Effect of venom gland extracts of the South American brown spider, Loxosceles laeta, on in vitro protein synthesis; Suarez G et al.; There was no effect of the venom extract on incorporation of phenylalanine into protein from phenylalanyl-tRNA . In contrast, the esterification of amino acids with tRNA was inhibited by the venom extracts in a dose-dependent manner, with an apparent preservation of the covalent structure of aminoacyl-tRNA. Mol Gen Genet, 1983, 191(2), 301 - 6 Identification of an iron uptake system specific for coprogen and rhodotorulic acid in Escherichia coli K12; Hantke K; With the lac operon fusion technique, mutants were isolated in two genes that specify two outer membrane proteins designated FhuE (76 K) and Fiu (83 K) . The synthesis of both proteins was increased under low iron growth conditions . The FhuE-protein was shown to be necessary for iron uptake via coprogen, an iron chelator produced by certain fungi, e.g . Neurospora crassa . In addition to fhueE the genes fhuCDB, tonB and exbB were necessary for iron coprogen uptake . The gene fhuE was mapped between kdp and gltA near 16 min on the genetic map of E . coli K12, while gene fiu was mapped near 18 min between chlA and chlE . Nor iron transport system could be assigned as yet to the Fiu protein. Mol Gen Genet, 1983, 191(2), 276 - 81 Involvement of the mismatch repair system in base analogue-induced mutagenesis; Bebenek K et al.; The influence of the mismatch repair system, and the role of mutS, mutR, and mutL genes, in mutagenesis induced by n2ome6Ade, n2oh6Ade and n2Pur have been investigated . From the frequency of reversion of Arg-Thr- and His- markers in AB2497, and its mut- derivatives, it was concluded that mismatches introduced by n2-ome6Ade and n2oh6Ade are better substrates for mismatch repair enzymes than that introduced by n2Pur . All these mut-gene products are more active in removing spontaneous or base analogue-induced mismatches which, when unexcised, lead to transversion of base repairs, than those which lead to transitions . Active engagements of mutL, mutR, or mutS gene products depend on the kind of mutation, the site of mutagenesis, and the inducing agent . Dam- cells are over-mutated by both n2ome6Ade and n2oh6Ade, but are hyper-sensitive to n2oh6Ade only . It is proposed that hyper-sensitivity of dam- cells is due not only to an increase in overlaping gap formation on both strands of DNA, but to a greater lability of the impaired cells . Results are presented which strongly suggest that n2ome6Ade in mut+ cells and n2oh6Ade in mut- only, can induce GC leads to TA transversions.