Escherichia coli

Contrib Microbiol Immunol, 1979, 6, 100 - 10
Structure and function of plasmid ColE1 and related plasmids; Sherratt DJ et al.; Analysis of plasmid ColE1, its naturally occurring relatives ColK and CloDF13, and a wide range of ColE1 derivatives containing either insertions or deletions of genetic material has allowed localization on the ColE1 genome of DNA sequences responsible for colicin E1 synthesis, immunity to colicin killing, conjugal mobility and incompatibility . We have examined incompatibility between pairs of ColE1 derivatives ranging in size from 2.6 to 13.8 Md . Though all the plasmids tested exerted ColE1 incompatibility, a definite pattern was observed regarding the dominant plasmid in any pair tested (i.e . the plasmid that displaces the other from a heterozygote) . Usually the larger plasmid is displaced . We conclude that loci for incompatibility reside within 0.7 kb of the ColE1 replication region . A model is presented to explain both the incompatibility data and the observation that the fraction of total DNA occurring as ColE1-like plasmid in a cell is approximately constant . Transposons Tn1 and Tn3 (3.2 Md; Apr and approximately 85% homologous), Tn501 (5.5 Md; Hgr), and Tn7 (9.3 Md; Tpr Smr) can all be transposed into ColE1 . Though all have closely related . Tn501 and Tn7 do not complement transposition of Tn3 transposition defective deletions . A Tn3-specified 19,000 dalton protein is absent in one particular class of transposition-defective deletion.

Neoplasma, 1979, 26(3), 281 - 5
Peripheral blood lymphocyte nucleoi of rats with Yoshida ascitic sarcoma and the effect of endotoxin; Likovsky Z et al.; Nucleoli of lymphocytes were studied in the peripheral blood of male Wistar rats bearing Yoshida ascitic tumor untreated and treated with Escherichia coli endotoxin . Both the neoplastic process and the endotoxin produced an increase of peripheral lymphocytes with "active" nucleoli in number . The treatment of experimental animals bearing the tumor with the endotoxin decreased their mortality and enhanced the increase of the lymphocytes with "active" nucleoli in their peripheral blood.

Microbiol Immunol, 1979, 23(11), 1077 - 83
"Pseudolysogenization" by RNA phage Q beta; Watanabe I et al.; We isolated fairly stable lysogenic-like bacteria from a lysogenic state established between an amber mutant for the maturation protein gene of RNA phage Q beta (Q beta am 205) and its nonpermissive host BE110 . These bacteria contained few mature phages intracellularly (less than 10(-3) plaque forming unit per cell), continued to grow with a potentiality to produce Q beta am 205 spontaneously, and showed an immunity-like response against homologous phage infection . These characteristics were maintained by growth in liquid medium containing anti-Q beta serum . We designated these cells as pseudolysogenic bacteria . The relative amounts of RNA genomes in these pseudolysogenic cells (about 10(2) infectious RNA strands per cell) indicated that the RNA genomes could replicate in nonpermissive cells and be distributed in daughter cells synchronizing well with cell division.

Genetika, 1979, 15(2), 209 - 19
{Incorporation of the ampicillin resistance transposon into the Escherichia coli K-12 chromosome and into plasmids}; Volozhantsev NV et al.; The mutant pEG1 of R-factor RP4 with temperature-sensitive defect in replication, carrying a transposable ampicillin resistance element Tn1 was used to define the frequency of insertion of this element into Escherichia coli K-12 chromosome and some other plasmids . Our results indicate that the frequency of colony forming by bacteria with pEG1-factor on ampicillin medium in non-permissive conditions corresponds to the frequency of Tn1 insertion into bacterial chromosome or some other plasmid (in case when the strains are carrying a second plasmid) . The frequency of Tn1 insertion into the chromosome is about 4.10(-4) . The defect in recA gene produce no serious change in the frequency of Tn1 insertion into the bacterial chromosome . The translocation of Tn1 element from pEG1-factor to R483, R6 and ColE1 plasmids occurs at 10 to 100-fold-higher frequency than from the plasmid to the chromosome . The insertion of Tn1 into the F'-factor KLF10 and R-factor R64-11 occurs at far lower frequency than that to plasmids R6, R483, or ColE1.

Genetika, 1979, 15(2), 200 - 8
{Asymmetry in the frequencies of reciprocal recombinants in crosses of T4 phage rIIB mutants}; Shcherbakov VP et al.; The frequencies of reciprocal recombinants in crosses between rIIB mutants of T4 phage were shown to differ from each other . In terms of the correction model, this asymmetry of genetic recombination was used to measure the comparative correctability of the mismatched regions to the wild type and to the mutant alleles . The data obtained are in quantitative agreement with the analogous values for the same mismatched regions determined by comparison of the markers located at the same site . This strongly suggests that the asymmetry of genetic recombination in T4 reflects the corresponding difference in rates of correction of the mismatched regions in heteroduplexes in opposite directions.

Enzyme, 1979, 24(6), 353 - 7
Escherichia coli tRNA (uracil-5-)-methyltransferase: Inhibition by analogues of adenosylhomocysteine; Shugart L et al.; Structural analogues of adenosylhomocysteine (AdoHcy) have been tested as inhibitors of a tRNA(uracil-5-)-methyltransferase preparation obtained from Escherichia coli . All analogues tested gave linear competitive inhibition kinetics with adenosylmethionine (AdoMet) as the variable substrate . Comparison of the Ki values obtained leads to the following conclusions concerning the specificity of the AdoMet-AdoHcy binding site on the enzyme: (i) the terminal amino group of the amino acid moiety is necessary for activity; (ii) both a chiral change of the asymmetric carbon atom of homocysteine and the presence of the terminal carboxyl group contribute little towards inhibitory activity; (iii) analogues in which the amino function of the adenyl moiety is modified or substituted are still potent inhibitors; (iv) inhibitor specificity is considerably reduced when adenine is replaced by a pyrimidine base.

Adv Exp Med Biol, 1979, 123, 59 - 78
L-Glutamate decarboxylase; Sze PY; Much progress has been made in recent years regarding enzymological aspects of mammalian brain GAD, such as its purification and characterization, but some uncertainty still remains concerning its molecular weight and forms, and its subunit structure . The availability of antibodies to this enzyme has allowed immunocytochemical studies which have provided important information on the intrinsic organization of GABA-ergic neurones in the CNS, particularly in the cerebellum and nigrostriatal pathway . With the increased understanding of the enzymology of GAD and the distribution of central GABA-ergic neurones, it is becoming feasible to study the regulatory biochemistry of GAD in terms of control and adaptive mechanisms at the cellular level . In our own laboratory, as well as in others, initial approaches have already begun . Obviously, cellular regulation of this phenotypic enzyme is an important issue for the understanding of GABA-ergic neurones and their functions.

Infection, 1979, 7 Suppl 5, S443 - 5
Efficacy of bacampicillin and ampicillin in experimental pyelonephritis in the rat; Ritzerfeld W; Bacampicillin and ampicillin were tested and compared with each other in a model of acute, obstructive pyelonephritis in the rat . The compounds were administered orally at five dose levels ranging from 50 mg/kg to 150 mg/kg . Bacampicillin was found to have a greater therapeutic activity than ampicillin, particulary at the higher doses, indicating that its improved absorption properties make it a therapeutically more effective compound than ampicillin.

Arch Exp Veterinarmed, 1979, 33(2), 237 - 46
{Effect of reduced gastrointestinal motility on the regulation of gastrointestinal flora and the pathogenesis of coli enterotoxinemia in market swine}; Schulze F; Opium tincture and Spasmentral were applied to piglets early after weaning and reduced their gastro-intestinal motility, which, however, caused only very minor changes in quantitative germ flora composition in those first days . Short-time suppression of gastro-intestinal motility obviously does not result in detrimental consequences to the organism as a whole, since there seem to be several factors which are involved in the control and regulation of the intestinal germ flora . Impairment of gastro-intestinal motility appeared to be of no importance to the pathogenesis of coli-enterotoxaemia, as it was not followed by higher incidence of the disease.

Acta Biochim Pol, 1979, 26(1-2), 29 - 38
Effect of temperature and 4,6'-diamidine-2-phenylindole on restriction of supercoiled Col E1 DNA by Eco RI endonuclease; Stepien E et al.; Supercoiled Col E1 DNA is split by Eco RI endonuclease at 37 degrees C without intermediate formation of open circular DNA . Accumulation of this restriction product is observed at low temperature . The fluorescent dye, 4,6'-diamidine-2-phenylindole (DAPI) inhibits restriction by Eco RI endonuclease . This effect is due to the DAPI:DNA rather than to the DAPI:Eco RI interactions.

Vet Med Nauki, 1979, 16(1), 28 - 32
{Immunostimulating activity of certain subcellular fractions of Escherichia coli O138:K81:H19}; Ruskova M; A 24-hour culture of Escherichia coli 0138:K81:H19 was used to isolate a soluble cytoplasmic fraction, an O antigen, and an unsolube cell ingredient . Their immunogenic action was followed up through subcutaneous vaccination of mice and the production of humoral antibodies in rabbits . It was found that the cytoplasmic ingredient was a slightly toxic protective antigen forming considerable immunity in mice and a comparatively high titer of antibodies in rabbit sera . The unsoluble cell ingredient and the O antigen proved comparatively toxic and did not produce favourable immune response . Discussed in the use of the cytoplasmic ingredient as a vaccine as well as the type of the immunoglobulins produced.

Microbiol Immunol, 1979, 23(7), 569 - 80
Integration of temperature-sensitive nonconjugative plasmid carrying kanamycin gene into conjugative R plasmids; Katsumata R et al.; A nonconjugative R plasmid, rMS3, whose molecular weight was 2.4 X 10(7) daltons, possessed a kanamycin resistance gene and was thermosensitive in its maintenance in Escherichia coli strains . We mobilized rMS3 with a conjugative R plasmid, R100 or T-tet, and obtained cointegrates carrying all the parental resistance markers . Various markers of the cointegrates were frequently deleted by P1 transduction and the deletion patterns among the different cointegrates were differed from each other . The cointegrates were thermoresistant, but the thermosensitive replicon could be segregated from the thermoresistant cointegrate by deletion . Some cointegrates between rMS3 and T-tet showed a derepressed state of transferability because of the integration of rMS3 and T-tet showed a derepressed state of transferability because of the integration of rMS3 into the regulator gene of the transfer loci . The genome size of the cointegrate so far tested was the sum of the sizes of the parental plasmids, indicating that the whole genome of rMS3 could integrate into various sites of the conjugative plasmids R100 and T-tet.

Biochimie, 1979, 61(5-6), 671 - 9
Methylated amino acids in ribosomal proteins from Escherichia coli treated with ethionine and from a mutant lacking methylation of protein L11; Alix JH et al.; In the present study, the nature, proportions and distribution of methylated amino acids in ribosomal proteins from Escherichia coli grown in the presence of ethionine and from mutant prm 1 were studied . The undermethylated ribosomes had been labeled by addition in vitro or in vivo of radioactive methyl groups from S-adenosylmethionine or from methionine . The following compounds were identified : N alpha-mono-, di- and trimethylalanines, N epsilon-mono-, di- and trimethyllysines, methylamine and N alpha-trimethylalanyllysine . Except for the latter compound and N-alpha-dimethylalanine, all other derivatives had been previously identified in the literature . It is shown that the dipeptide had been in the past mistaken for N epsilon-monomethyllysine, and arises through incomplete hydrolysis in 24 hrs of the N-terminal peptide bond of protein L11 . The results of the present study are discussed in the light of previous work on ribosomal protein methylation by the authors and other workers in the field.

Arzneimittelforschung, 1979, 29(7), 1062 - 4
Endotoxin, fever and anomalies of development in rabbits . Short communication; Hellmann W; E . coli endotoxin was injected i.v . in rabbits (White New Zealands) on day 9 of gestation . The rise of temperatures was examined by thermoelectric recording . On day 29 of pregnancy the rabbits were killed, the uteri examined for resorptions and the fetuses inspected for malformations . The results were compared with those of control animals . The group treated with E . coli endotoxin showed a significant higher resorption and malformation rate . On the basis of the slight increase of temperatures (up to 1.1 degrees C above normal value), it is supposed that the endotoxin-induced fever did not participate in the teratogenic effects observed.

Arzneimittelforschung, 1979, 29(5), 804 - 7
Ontogenic drug studies in calves . II . Changes in salicylate levels and metabolism in calves with diarrhoea; Sechserova M et al.; Acetylsalicylic acid (ASA) was administered by oral route to calves and mice . A comparison of plasma levels of salicylates and salicyluric acid was performed in healthy and diarrhoic calves . The calves were infected with E . coli enterotoxin producing strains . During the 6 h observation period increased levels of salicylates were found in all age groups of calves (1-60 days) . There were no significant differences in salicyluric acid plasma levels between controls and diarrhoic animals . Intravenous injection of cholera toxin in mice caused lower levels of total salicylates, but increased levels of salicylic acid and salicyluric acid . The importance of adequate animal model is discussed.

Antonie Van Leeuwenhoek, 1979, 45(2), 253 - 63
Competition between an Escherichia coli tyrosine auxotroph and a prototrophic revertant in glucose- and tyrosine-limited chemostats; Mason TG et al.; A tyrosine-requiring strain of Escherichia coli was grown in tyrosine-limited chemostats at a range of dilution rates between 0.08 h-1 and 0.42 h-1, conditions which always resulted in the selection of a prototrophic revertant population able to synthesise tyrosine . Analysis of the two-membered mixed cultures which arose showed that the prototrophic population outgrew the auxotroph since its growth rate was not restricted by the growth-limiting concentrations of exogenous tyrosine . During the take-over of the culture, the prototroph population grew exponentially but the specific growth rate increased with decreasing dilution rate of the competition experiments . In glucose-limited chemostats (in the presence of non-growth-limiting concentrations of tyrosine) of the tyrosine-requiring strain, prototrophs were never detected . Constructed two-membered mixed cultures with both populations competing for limiting amounts of glucose, showed that the prototroph was less competitive than the auxotroph.

Agents Actions Suppl, 1979, (4), 147 - 55
The role of thromboxane A2 in endotoxin-induced aggregation of guinea-pig platelets in vitro; Bult H et al.; Large concentrations of endotoxin lipopolysaccharides (LPS) E . coli O127:B8 and E . coli O26:B6 were needed for induction of platelet aggregation in citrated platelet rich plasma (PRP) from normal guinea-pigs . When guinea-pigs were actively immunized with LPS E . coli O127:B8 their PRP became more sensitive to the aggregatory effects of this type of LPS . The increase in sensitivity was rather selective since the responses to ADP and LPS E . coli O26:B6 remained unchanged . In endotoxin-stimulated PRP from normal guinea-pigs thromboxane A2 (TXA2) was not detectable by bioassay . Thus biosynthesis of TXA2 seemed to be of little importance in endotoxin-induced platelet responses in normal citrate PRP . LPS E . coli O127:B8, but not LPS E . coli O26:B6, was a potent inducer of the biosynthesis of TXA2 in sensitized PRP . Under those conditions endotoxin-induced aggregation seemed to be dependent on the endogenous biosynthesis of TXA2 by the platelets.

Vopr Onkol, 1979, 25(7), 64 - 7
{Ultraviolet-induced effect of N-nitrosamines on the in vitro parameters of DNA fusion}; Iamshanov VA; The results of studies have shown the UV-induced decrease of melting temperatures of the DNA of E . coli and chick erythrocytes under the influence of simple N-nitrosamines (NDMA, NDEA, NDPA) . Either UV or nitrosoamines separately failed to effect the DNA, or their action was insignificant . It is suggested that this effect may be partly due to the action of UV on DNA.

Scand J Urol Nephrol, 1979, 13(2), 155 - 60
Continued experimental study on the pathogenesis of sporadic bacteriuria in the rat; Hjort EF; An experimental model implying ligature of the left ureter in the rat has previously (1977) been described by the author . The same model has been used in the experiments which are presented in this paper . The aim has been to study further the hematogenous seeding of bacteria to the hydronephrotic left kidney . The experiments seem to confirm the author's view that sporadic hematogenous infection with intestinal bacteria occasionally takes place and can be demonstrated by this method . Intravenous injection of E . coli showed that the minimal kidney infecting dose amounted to 0.5 ml E . coli 10(6) bacteria per ml . The author found considerable increase of sporadic infection after splenectomy and partial liver resection.

Genetika, 1979, 15(8), 1522 - 4
{Enhanced UV sensitivity of Escherichia coli strain uvrA crp}; Skavronskaia AG et al.; UV-sensitivity and UV-induced mutability to tryptophan independence has been studied in isogenic crp, cya, crp+, uvrA crp and uvrA crp+ strains of Escherichia coli . crp and cya strains are found to have the same UV-sensitivity as an isogenic wild type strain . UV-sensitivity of uvrA crp strain seems to be one-two orders increased as compared with the sensitivity exhibited by the uvrA - crp+ strain . The yield of UV-induced revertants is slightly higher in crp, cya and uvrA crp strains than in the wild type cells . The existence of cap-dependent inducible error-free repair pathway is supposed due to the data obtained.

Genetika, 1979, 15(7), 1206 - 20
{Genetic control of the formation of plasmid F' . I . Effect of recA- and seg-2 mutations in an Hfr donor strain on the character of plasmid F' formation}; Gorelov VN et al.; Assuming the similarity of the processes of illegitimate recombination, such as deletion formation, with the process of F' plasmid formation, we have undertaken the study of the influence of recA- and seg- alleles of Hfr donor on the F' plasmid formation . The data obtained demonstrate the strong influence of donor genotype on the frequency of F' plasmid formation and on the nature of F' plasmids formed, thus demonstrating that the most of F' plasmids have been formed via recombination in Hfr donor cells . The recA- mutation decreased the total yield of F' plasmids selected using both proximal and distal Hfr markers and affected drastically the distribution of the F' plasmids inheriting different proximal unselected markers . The existence of recA-dependent and recA-independent modes of F' plasmid formation was demonstrated . The Escherichia coli chromosome contains regions which involve preferentially in recA-dependent (between proA and gal, and clockwise from gal) or recA-independent (between leu and proA, and the region counterclockwise from argE) recombination . The seg-2 mutation causes only partial block of both recA-dependent and recA-independent recombination pathways, however it causes dramatic decrease of genetic exchanges leading to the formation of the type II F' plasmids . Both seg- and recA- mutations decrease the frequency of the formation of Tra+ F' transconjugants . The percent of Tra- transconjugants, which remain sensitive to MS2 and Q beta donor specific phages, also drops significantly under the influence of the recA- and seg- alleles . Thus, the recombination involving the F structure in wild type strains and seg- mutants occures preferentially in the points of F outside the regions essential for transfer and sensitivity to male specific phages, while in recA- and recA-ges- strains the points inside these regions (tra operon) frequently involved in F' plasmid looping out . There exist more strict correlation between the fertility and sensitivity to phage Q beta than to phage MS2.

Res Vet Sci, 1979 Jan, 26(1), 97 - 101
The pathogenesis of experimental Escherichia coli mastitis in newly calved dairy cows; Hill AW et al.; Experimental infections of the mammary gland of newly calved cows with 500 serum resistant Escherichia coli produced a very severe form of mastitis when compared with animals in mid-lactation . Ten hours after infection the bacteria had multiplied in the milk to very high numbers (10(6)--10(7)/ml) and the animals showed signs of pyrexia, anorexia and diarrhoea . Initially the gland and milk showed little or no clinical signs of mastitis, but later the secretion became a viscous, serous fluid with little or no casein or fat . A delay in diapedesis of neutrophils into the gland appears to be the reason for the peracute state and lack of clinical signs . This form of pathogenesis may produce a paradoxical situation where the most severe cases of E coli mastitis cannot be diagnosed at a stage early enough for the animal to respond to therapy.

Folia Microbiol (Praha), 1979, 24(3), 224 - 7
A comparison of UV-induction in exponentially growing and resting Escherichia coli B/r Hcr+; Slezarikova V et al.; Using the method of two separate UV exposures the increase of UV resistance after various induction fluences in growing and resting Escherichia coli B/r Hcr+ was followed . In resting cells, the optimum induction energy fluence was found to be 30 J/m2 . In exponentially growing cells testing of induction has proved to be possible only under conditions of postincubation of cells with chloramphenicol after the second fluence . Under these conditions the induction energy fluence up to the observed 50 J/m2 resulted in an increased survival.

Exp Cell Biol, 1979, 47(3), 218 - 25
Particular RNA fragments as promoters of leukocyte and platelet formation in rabbits; Beljanski M et al.; Under well-defined conditions, ribosomal RNA from Escherichia coli is fragmented by pancreatic ribonuclease, leading to the appearance of particular RNA fragments . Some of these fragments act as primers for in vitro replication of DNA extracted from blood-cell and platelet-forming tissues . In experimental rabbits they restore in a rapid and harmless way normal circulating leukocyte and platelet levels when these have been drastically decreased by various chemotherapeutic agents mainly used in anticancer therapy . Imbalance between polynuclear and lymphocyte count provoked in rabbits by cyclophosphamide can be rapidly corrected by treating the animal with active RNA fragments.

Eksp Med Morfol, 1979, 18(2), 76 - 81
{Changes in the motor activity of an isolated intestinal loop from the jejunum of dogs exposed to an endotoxin}; Tsafarov M; The author examined the motor activity of an isolated Loop in vivo of founonnarcotised dogs under the conditions of chronic experiments before and after administration of E . coli in dose of 0.1, 0.5, 1.0, and 2.0 mg/body weight . There was inhibition of the movements of the intestinal loop, which was manifested by a reduction of the frequency and amplitude of the intestinal contractions . The inhibition of the motor activity was explained by the disturbances in the circulation and neuro-bunoral control of the intestinal smooth muscle.

Contrib Nephrol, 1979, 16, 16 - 21
Immunological aspects of pyelonephritis; Hanson LA et al.; Several virulence factors, such as O and K antigens and capacity to attach to uroepithelial cells, seem to be required for Escheria coli to cause acute pyelonephritis . These factors induce an immune response, however, which can modify the course and clinical expression of the infection . During acute pyelonephritis, autoantibodies to the Tamm-Horsfall protein increase . These antibodies, which probably are evoked by a cross-reaction noted between structures of E . coli LPS and the Tamm-Horsfall protein, may add to the renal tissue engagement in interstitial nephritis caused by bacterial pyelonephritis.

Circ Shock Suppl, 1979, 1, 69 - 79
Lipid metabolism in endotoxic shock; Spitzer JJ; A brief overview of the alterations in the control of free fatty acid (FFA) and triglyceride (TG) turnover following the administration of Escherichia coli endotoxin is presented . Hormone-sensitive lipase activity was increased following either in vivo or in vitro administration of endotoxin . In conscious dogs, the rate of appearance of glycerol was also increased while that of FFA was not changed, indicating that in addition to increased lipolysis, increased reesterification in the adipose tissue may also be present . Myocardial utilization of FFA was decreased and that of lactate increased following endotoxin both in vivo and in vitro using isolated myocytes . Both myocardial and adipose tissue lipoprotein lipase activity were decreased following endotoxin, indicating a possible decrease in TG removal by these tissues . Additional studies are warranted to further elucidate the interrelation between the changes of lipid and carbohydrate metabolism and those of hemodynamics in shock.

Nucleic Acids Res, 1979, 6(6), 2363 - 79
Segmental flexibility in Escherichia coli ribosomal protein S1 as studied by fluorescence polarization; Chu YG et al.; Ribosomal protein S1 covalently reacts with approximately one equivalent of iodoacetylethylenediamine (1,5-napthol sulfonate (IAEDANS) or iodoacetylaminofluorescein (IAAF) . The product AEDANS-S1 can bind to 30S ribosomal subunits lacking S1 as shown by polyacrylamide-agarose gel electrophoresis AEDANS-S1 and AAF-S1 when added back to S1-depleted 30S subunits modulate poly(U)-dependent polyphenylalanine synthesis in the presence of IF3 in a very similar way to unmodified S1 . AEDANS-S1 also stimulates RI7-dependent fMet-tRNA binding to 1.0M NH4C1 washed ribosomes whereas AAF-S1 does not . Both static and nanosecond fluorescence polarization techniques were used to study the rotational motions of AEDANS-S1 . Several previous studies had indicated that S1 is a highly extended protein which can be modeled by a prolate ellipsoid with an axial ratio of 10 to 1 . However, the rotational correlation time we find is about half that expected for such a particle . This suggests that S1 is a flexible protein with at least two domains that can rotate independently.

Mol Biol (Mosk), 1979 Jan-Feb, 13(1), 216 - 27
{Unprimed synthesis of poly (d(A-T)), catalyzed by a preparation of Escherichia coli DNA polymerase I}; Nazarenko IA et al.; The initial events of the de novo synthesis of poly{d(A-T)}, catalyzed by preparations of E . coli DNA-polymerase I, were investigated . The data provide evidence that deoxynucleoside diphosphate: oligonucleotide deoxynucleotidyl transferase (dNDP-transferase), the enzyme which is able to catalyze unprimed polymerization of dNDP, participates in the process of initiation . This conclusion is based on the following data: 1) preincubation of E . coli DNA-polymerase I preparation with dADP and dTDT abolishes a lag-period in the poly{d(A-T)} synthesis; 2) dithiothreitol and N-ethylmaleinide, inhibitors of dNDP-transferase, inhibit de novo synthesis of {d(A-T)}-copolymer by preparations of E . coli DNA-polymerase I but do not effect primed synthesis ensured by this enzyme . High concentration of the substrate have similar effect . Using two-dimentional thin-layer chromatography and microcolumn chromatography on TEAE-cellulose we have shown that preliminary incubation of DNA-polymerase I preparations with dADP and dTDP results in the synthesis of short oligonucleotides (from di- to decanucleotides) . Hydrolysis of these oligonucleotides with dilute sulfuric acid demonstrates that among the reaction products prevail oligoadenylates and oligothymidylates, but an appreciable amounts of heterooligomers including oligo{d(A-T)} were revealed as well . The model of so called de novo synthesis of regular polynucleotides is proposed, according to which dNDP-transferase, an accompanying enzyme in the preparations of DNA-polymerase I E . coli, is carrying out the synthesis of short oligonucleotides which form template-primer complexes repeatedly replicated by the DNA-polymerase I E . coli.

Genetika, 1979, 15(5), 823 - 30
{Comparative study of mutator-gene prv and several other mutator-genes of Escherichia coli K-12}; Khmel'nitskii MI et al.; Mutations prv1, prv2 and mutR34, increasing frequencies of intragenic recombinations, are found not to complement and therefore to be alleles of one gene . Checking for the influence of mutator genes mutS3, mutT1 and uvrE502 on the intragenic recombination in conjugational crossings has shown that mutators mutS3 and uvrE502 increase the frequency of intragenic recombinations while mutT1 does not change it . None of the examined mutator genes influence the conjugational frequencies of recombination . A supplementary analysis for the mutability of the mutant prv1 has been carried out . The prv1 mutation can induce mutations of the frameshift type . Mutations uvrA6, recB21, recC22 and lexA produce no influence on the display of a mutator effect of the prv1 mutation.

Chir Forum Exp Klin Forsch . 1979;:261-4.
Enhancement of local immune response in the treatment of experimental peritonitis; Hau T et al.; We conclude from these experiments that the host defense in peritoneal infections rests largely on the phagocytic cells attracted into the peritoneal cavity by the offending organism, and that an increase in the number of available phagocytes by pretreatment with chemotactic substances protects against lethal peritoneal infections . There seems to be a direct relationship between the number of available phagocytes in the peritoneal cavity at the time of inoculation and the reduction of mortality in experimental peritonitis (Fig . 1).

Circ Shock, 1979, 6(1), 13 - 21
Pulmonary vascular response to endotoxin in normal and lymphocyte depleted sheep; Bohs CT et al.; The cardiopulmonary effects of intravenously administered Escherichia coli endotoxin were studied in unanesthetized sheep . One group of animals was depleted of circulating T-lymphocytes while a non-depleted group served as control . T-lymphocyte depletion was accomplished by chronic thoracic duct drainage of lymph, removal of lymphocytes by continuous flow centrifugation and return of the cell free lymph intravenously . The T-lymphocyte depleted sheep demonstrated markedly obtunded increases in pulmonary arterial pressure and pulmonary vascular resistance following endotoxin when compared to the effects of the lipopolysaccharide in control animals . additionally, the lymphocyte depleted group showed a significant augmentation of myocardial contractility which occurred at the same time as marked systemic hypotension . This period of extreme hypotension following endotoxin is presumed to be accompanied by a reflex increase in the activity of the sympathetic nervous system . The control sheep, although equally hypotensive at this time, did not demonstrate a significant increase in myocardial contractility from the preendotoxin value . The results of these experiments indicate that T-lymphocytes may mediate some of the pathophysiological effects of bacterial endotoxin on the cardiovascular system.

Nucleic Acids Res, 1979, 6(5), 1831 - 41
DNA sequences of the integration sites and inverted repeated structure of transposon Tn3; Takeya T et al.; The nucleotide sequence of the "inverted repeat" structure of the transposon Tn3 was determined by the DNA sequencing procedure developed by Maxam and Gilbert(1) . The sequence, 38 base pairs long, is as follows: 5'-GGGGTCTGACGCTCAGTGGAACGAAAACTCACGTTAAG..(Tn3) 3'-CCCCAGACTGCGAGTCACCTTGCTTTTGAGTGCAATTC. . The integration of Tn3 is associated with a directly repeated sequence of 5 nucleotides appearing at each end of Tn3 . The two directly repeated sequences so far determined are not the same . Furthermore, there is no homologous structure around the integration point of Tn3.

Nucleic Acids Res, 1979, 6(5), 1817 - 30
Physical map of the seven ribosomal RNA genes of Escherichia coli; Boros I et al.; Escherichia coli DNA was digested with restriction endonucleases BamHI, PstI, EcoRI, SalI, HindIII, XhoI, BglII, SmaI, HpaI and with selected double and triple combinations of the same enzymes . The digests were electrophoresed and hybridized with 32P-labelled ribosomal RNA by using the Southern blotting technique . The resulting bands could be arranged into seven groups, and it was possible to construct a unique physical map of the seven rRNA genes (operons) of the bacterial chromosome . Mapping information obtained on several transducing phages and recombinant plasmids carrying rRNA genes, and mapping data published in the literature helped to determine the final map . The results suggest that phage lambda daroE152 carries a "hybrid" rRNA gene which was probably formed by recombination between two different chromosomal rRNA genes.

Nucleic Acids Res, 1979, 6(5), 1775 - 90
Max-Planck-Institut für Molekulare Genetik, Abteilung Wittmann, Berlin-Dahlem, GFR; Zwieb C et al.; It is well established that when E . coli 30S ribosomal subunits are irradiated with ultraviolet light under mild conditions a specific cross-link is formed between protein S7 and the 16S RNA . Methodology is presented for the analysis of the single nucleotide residue concerned in this cross-link . Firstly, the identity of the ribonuclease T1 octanucleotide attached to S7 is confirmed by a new method, which involves isolation and analysis of S7-polynucleotide complexes containing 30 -- 40 nucleotides . Secondly, the isolated S7-octanucleotide complex is digested successively with ribonuclease A, proteinase K and ribonuclease T2, and the nucleotides liberated are identified . The results show unambiguously that uridine residue number 1239 in the 16S RNA sequence is cross-linked to protein S7.

Nucleic Acids Res, 1979, 6(5), 1761 - 74
The regulatory region of MS2 phage RNA replicase cistron . IV . Functional activity of specific MS2 RNA fragments in formation of the 70 S initiation complex of protein biosynthesis; Borisova GP et al.; The initiation region of the MS2 replicase cistron can be isolated as a fragment 59 bases in length protected from RNAase by the binding of the coat protein which serves as a translational repressor . This fragment MS2 R(-53 leads to 6) starts 53 bases before the initiation codon and retains full activity in binding ribosomes . We have investigated the functional activity in initiation of a series of fragments from this region variously shortened from the 5'-end . Ribosome protected fragments starting 17 or 21 bases before the AUG are unable to rebind to ribosomes . The shortest fragment which has this activity was produced by partial S1 nuclease digestion and starts 33 to 35 bases before the AUG . The initiation signal comprises some nucleotides between 21 and 33 bases before the initiation codon and the regulatory region responsible for initiation is longer than that protected by the ribosome in the final initiation complex.

Infection, 1979, 7(2), 64 - 6
Effect of in vitro treatment with reducing drugs on structure and function of human secretory immunoglobulin A; Plebani A et al.; Samples of unstimulated whole saliva from 15 healthy children with 0.5--6 mg/100 ml of secretory IgA and from 10 healthy adults with 4--18 mg/100 ml of secretory IgA were pooled and treated in vitro with dithiothreitol and alpha-mercaptopropionylglycine . The effect of these reducing drugs on the immunochemical properties of secretory IgA was evaluated . Dithiothreitol induced depolymerization of secretory IgA and splitting of the secretory piece from the IgA molecule; furthermore it strongly reduced the titer of secretory antibodies to Escherichia coli antigens . The drug alpha-mercaptopropionylglycine apparently did not affect either the polymeric structure of secretory IgA or the titer of secretory anti-E . coli antibodies; however it induced splitting of the secretory piece . On the whole it appers that drugs with reducing properties, currently employed for liquifying mucous secretions in clinical practice, should be carefully evaluated for possible depressive side-effects on local immunity.

Mutat Res, 1979 Jan, 59(1), 15 - 26
Effect of mutagens, chemotherapeutic agents and defects in DNA repair genes on recombination in F' partial diploid Escherichia coli; Norin AJ et al.; The ability of mutagenic agents, nonmutagenic substances and defects in DNA repair to alter the genotype of F' partial diploid (F30) Escherichia coli was determined . The frequency of auxotrophic mutants and histidine requiring (His-) haploid colonies was increased by mutagen treatment but Hfr colonies were not detected in F30 E . coli even with specific selection techniques . Genotype changes due to nonreciprocal recombination were determined by measuring the frequency of His- homogenotes, eg . F' hisC780, hisI+/hisC780, hisI+, arising from a His+ heterogenote, F' hisC780 hisI+/hisC+, his1903 . At least 75% of the recombinants were homozygous for histidine alleles which were present on the F' plasmid (exogenote) of the parental hetergenote rather than for histidine alleles on the chromosome . Mutagens, chemotherapeutic agents which histidine alleles on the chromosome . Mutagens, chemotherapeutic agents which block DNA synthesis and a defective DNA polymerase I gene, polA1, were found to increase the frequency of nonreciprocal recombination . A defect in the ability to excise thymine dimers, uvrC34, did not increase spontaneous nonreciprocal recombination . However, UV irradiation but not methyl methanesulfonate (MMS) induced greater recombination in this excision-repair defective mutant than in DNA-repair-proficient strains . Mutagenic agents, with the exception of ethyl methanesulfonate (EMS), induced greater increases in recombination than the chemotherapeutic agents or the polA1 mutation . EMS, which causes relatively little degradation of DNA, was more mutagenic but less recombinogenic than MMS, a homologous compound ths that inhibition of DNA occurring single-stranded regions in replicative intermediates of the DNA . Mutagens which cause the rapid breakdown of DNA may, in addition, introduce lesions into the genome that increase the number of single-stranded regions thus inducing even higher frequencies of recombination.

J Gen Microbiol, 1979 Jan, 110(1), 61 - 6
Uroporphyrin- and coproporphyrin I-accumulating mutant of Escherichia coli K12; Chartrand P et al.; A new type of haem-deficient mutant was isolated in Escherichia coli K12 by neomycin selection . The mutant was deficient in uroporphyrinogen III cosynthase activity as indicated by the accumulation of uroporphyrin I and coproporphyrin . The mapping of the corresponding hemD gene by P1-mediated transduction showed that the new gene was located between ilv and cya, at min 83 on the chromosomal map of Escherichia coli K12.

J Gen Microbiol, 1979 Jan, 110(1), 47 - 59
Transfer of a gene for sucrose utilization into Escherichia coli K12, and consequent failure of expression of genes for D-serine utilization; Alaeddinoglu NG et al.; As the first stage in investigating the genetic basis of natural variation in Escherichia coli, the gene(s) conferring the ability to use sucrose as a carbon and energy source (given the symbol sac+) was transferred from a wild strain to K12, which does not use sucrose . The sac+ region was transferred by two different methods . On both occasions it took a chromosomal location at minute 50.5 on the linkage map, between aroC and supN, in the region of the dsd genes, which confer the ability to use D-serine as a carbon and energy source . When the sac+ region was present in the K12 chromosome the bacteria were unable to use D-serine as a carbon and energy source . In F' sac+/dsd+ diploids, the dsd+ genes were similarly not expressed . Strain K12(sac+) bacteria were sensitive to inhibition by D-serine; they mutated to D-serine resistance with much greater frequency than did a dsd mutant of K12 . Such bacteria also mutated frequently to use raffinose . Strain K12(sac+) bacteria did not utilize sucrose when they carried a mutation affecting the phosphotransferase system.

J Gen Microbiol, 1979 Jan, 110(1), 211 - 20
Protein II influences ferrichrome-iron transport in Escherichia coli K12; Coulton JW et al.; Ferrichrome-promoted iron uptake in Escherichia coli K12 is strictly dependent upon the tonA gene product, a 'minor' outer membrane protein . By selection for mutants of E . coli resistant to phages which require 'major' outer membrane proteins as receptors, strains with pronounced protein deficiencies were constructed . Such strains were tested for anomalous behaviour of ferrichrome transport . No significant differences in iron uptake were detected in E . coli K12 strains with markedly reduced amounts of protein I . However, a reduction in the initial velocity (up to 40%) was observed in E . coli deficient in outer membrane protein II . This difference was only evident when cells were grown under iron-starvation conditions; it was abolished when cells were grown in rich medium . Kinetic parameters for ferrichrome transport were determined for maximum velocity but for Km; double reciprocal plots showed a biphasic nature, probably attributable to a limited number of outer membrane binding sites and to the multi-component nature of the ferrichrome-iron transport system.

Gene, 1979 Jan, 5(1), 45 - 58
The physical localization of the gene for ribosomal protein S20; Mackie GA; As a prerequisite to the examination of the structure and properties of the promoter for ribosomal protein S20 of Escherichia coli, I have determined the cleavage sites in lambdadapB2cI857S7 DNA for four restriction endonucleases . Subsequently, purified fragments obtained after digestion of this DNA with BamI or HindIII have served as templates for coupled transcription and translation . This has permitted the localization of the structural gene for S20 within a 1000 base pair segment of lambdadapB2cIB57S7 DNA . Cleavage of this DNA with HindIII partially inactivates the expression of S20 in vitro, implying that one HindIII site lies in or near a region essential for the expression of S20.

Gene, 1979 Jan, 5(1), 19 - 43
Restriction map of the region surrounding the EcoRI site in the pCR1 plasmid and analysis of an inserted ovalbumin gene; Wickens MP et al.; We have determined a restriction map of a 1650 base pair region surrounding the EcoRI site of the bacterial plasmid, pCR1 . We have used pCR1 as a vector in cloning synthetic ovalbumin double-stranded cDNA . Using the pCR1 restriction map, we have characterized the ovalbumin sequences inserted in one recombinant plasmid, pOvE12 . POvE12 appears to contain all, or nearly all, of the sequences found in full length, double-stranded cDNA synthesized in vitro.

Can J Comp Med, 1979 Jan, 43(1), 44 - 9
Permeability properties of swine small intestine: effect of a heat stable Escherichia coli enterotoxin; Presnell KR et al.; The permeability of weanling swine small intestine was estimated using measurements of filtration coefficients and equivalent pore size . Hypertonic solutions of mannitol, erythritol and urea were used to calculate reflection coefficients in the duodenum, mid jejunum and distal jejunum . Estimated effective pore radius was 6.4-7.4, 5.6-7.2 and 4.7-4.9A degrees in the three respective regions . Similarly the filtration coefficient induced by hypertonic solutions of mannitol decreased significantly in the distal jejunal segments . The results show an aboral gradient of decreasing permeability along the small intestine of the weanling pig . In situ incubation of loops in the proximal jejunum with a heat stable Escherichia coli enterotoxin for one hour did not significantly change the effective pore size as calculated from reflection coefficients of hypertonic solutions of erythritol and urea . However, the filtration coefficients of loops exposed to the enterotoxin were significantly greater than control loops with hypertonic solutions of erythritol and urea but not mannitol . This suggests the occurrence of a slight reduction in epithelial porosity . The results support the hypothesis that intestinal secretion induced by heat stable E . coli enterotoxin is not the result of an increased mucosal permeability.

Biochem J, 1979 Jan 1, 177(1), 129 - 36
Polypeptide-chain stoicheiometry and lipoic acid content of the pyruvate dehydrogenase complex of Escherichia coli; Hale G et al.; The pyruvate dehydrogenase multienzyme complex was isolated from Escherichia coli grown in the presence of {35S}sulphate . The three component enzymes were separated by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and the molar ratios of the three polypeptide chains were determined by measurement of the radioactivity in each band . The chain ratio of lipoamide dehydrogenase to lipoate acetyltransferase approached unity, but there was a molar excess of chains of the pyruvate decarboxylase component . The 35S-labelled complex was also used in a new determination of the total lipoic acid content . It was found that each polypeptide chain of the lipoate acetyltransferase component appears to bear at least three lipoyl groups.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 91 - 5
Thermosensory transduction in Escherichia coli: inhibition of the thermoresponse by L-serine; Maeda K et al.; Information processing of the thermoresponse in Escherichia coli was compared with that of the chemoresponse . Competition experiments between various chemical stimuli and the thermal stimulus showed that only L-serine was a potent inhibitor of the thermosensory transduction . The concentration of L-serine necessary for complete inhibition of the thermoresponse was about 0.1 mM . L-Serine at this concentration did not inhibit chemoresponses to many amino acids . Pleiotropic aspartate-taxis mutants (tar) showed normal thermoresponse but pleiotropic serine-taxis mutants (tsr) showed decreased or almost no thermoresponse . These results suggest that the thermosensory transducing system in E . coli has an intimate interaction with the chemosensory transducing pathway specific for L-serine . A simple model for the thermosensory transduction is discussed.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 386 - 90
Evidence for transcriptional regulation of orotidine-5'-phosphate decarboxylase in yeast by hybridization of mRNA to the yeast structural gene cloned in Escherichia coli; Bach ML et al.; From a large population of strains of Escherichia coli carrying shear fragments of yeast (Saccharomyces cerevisiae) DNA attached by in vitro recombination to the plasmid vector pMB9, two hybrid plasmids were selected that relieve the pyrimidine requirement of nonreverting pyrF mutants of E . coli . An 1100-base-pair DNA fragment common to the two complementing plasmids was recloned into another plasmid vector, pBR322; these new hybrids retained the ability to specify orotidine-5'-phosphate decarboxylase (orotidine-5'-phosphate carboxy-lyase, EC 4.1.1.23) synthesis in E . coli . Evidence is presented that this common fragment is yeast DNA and thus apparently carried the structural information for yeast orotidine-5'-phosphate decarboxylase, the product of yeast gene ura3 . A hybrid plasmid containing the 1100-base-pair fragment was used to measure levels of putative ura3 mRNA from yeast cultures labeled with {3H}adenine, ura3 mRNA was unstable with an apparent half-life of 10.5 min . Under different circumstances previously shown to alter the level of orotidine-5'-phosphate decarboxylase in yeast, a coordinate variation in proportion of labeled RNA complementary to the hybrid plasmid was found . These data support the hypothesis that regulation of the ura3 gene in yeast is at the level of transcription.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 260 - 4
Identification of a methyl-accepting chemotaxis protein for the ribose and galactose chemoreceptors of Escherichia coli; Kondoh H et al.; The ribose and galactose chemoreceptors of Escherichia coli have previously been identified as the ribose- and galactose-binding proteins . We now report the discovery of a methyl-accepting chemotaxis protein that functions in the transfer of receptor signals from these two binding proteins to the flagella . This protein is distinct from previously described methyl-accepting chemotaxis proteins . Its level of methylation is influenced by D-ribose, D-galactose, and certain structural analogues of them . This methyl-accepting protein is required for chemotaxis toward those attractants; mutants in the trg gene, which do not methylate this protein, are devoid of taxis toward D-ribose, D-galactose, and their analogues . In addition, methylation of the methyl-accepting protein in response to each of these attractants requires the appropriate binding protein . The binding protein's chemoreceptor function is required for such methylation, but its transport activity is not . Because the function of this methyl-accepting chemotaxis protein involves two of the best-characterized chemoreceptors, the discovery of this protein represents a promising base for further study of the linkage between chemoreceptors and flagella in bacteria.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 236 - 40
Translational and post-translational cleavage of M13 procoat protein: extracts of both the cytoplasmic and outer membranes of Escherichia coli contain leader peptidase activity; Mandel G et al.; The coat protein of coliphage M13 is an integral protein of the host cytoplasmic membrane at all stages of the infectious cycle . Both in in vivo and DNA-directed in vitro synthesis, it is initially made with an NH2-terminal "leader peptide" of 23 amino acids and is termed procoat . We now report that leader peptidase, and activity which removes the leader peptide and converts procoat to coat, is found in both the inner (cytoplasmic) and outer membrane of Escherichia coli . However, only cytoplasmic membranes will catalyze cleavage of procoat in the absence of detergent . Leader peptidase will cleave procoat either during translation or after protein synthesis is complete.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 189 - 93
Interaction of Escherichia coli RNA polymerase with promoters of several coliphage and plasmid DNAs; von Gabain A et al.; The interaction of Escherichia coli RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) with restriction fragments obtained from various E . coli related DNAs was studied in vitro . The DNAs investigated included several coliphage genomes (T5, lambda, T7, fd) and plasmid DNAs (pML 21, pSC101) . By using the nitrocellulose filter binding of the enzyme-DNA complexes, fragment-specific relative rates of complex formation as well as complex stabilities were determined . Promoter-specific relative rates of polymerase binding were derived from fragment-specific rates by taking into account the number of major binding sites for RNA polymerase within several DNAs . Estimates of the stability of complexes formed between some major binding sites and the enzyme were obtained by studying the rate of complex decay . Both characteristics--rate of complex formation and rate of decay--varied widely and independently of each other . The promoters reacting most efficiently with E . coli RNA polymerase were found in the early region of coliphage T5 whereas some promoters in pML 21, or for example, the lambda promoter PI, belong to signals binding the enzyme most slowly . Based on the second-order rate constant determined for the interaction of E . coli RNA polymerase with promoters of phage fd, the fastest promoters characterized so far reacted with rates in the order of 10(8) M-1s-1 . The hierarchy of promoters established here is of interest from the viewpoint that promoter strength correlates with the rate of polymerase binding . Among the promoters studied here this rate spans a range of 2 orders of magnitude.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 126 - 30
ATP-dependent renaturation of DNA catalyzed by the recA protein of Escherichia coli; Weinstock GM et al.; The product of the recA gene of Escherichia coli has been purified to near-homogeneity by a simple three-step procedure . Incubation of the recA protein with complementary single strands of DNA, Mg2+, and ATP results in the rapid formation of large DNA aggregates containing many branched structures . As judged by resistance to S1 nuclease and by electron microscopy, these aggregates contain both duplex and single-stranded regions . The renaturation and aggregation of DNA catalyzed by the recA protein is coupled to the hydrolysis of ATP . The recA protein purified from a cold-sensitive recA mutant does not catalyze DNA renaturation or aggregation at 28 degrees C, but does so at 37 degrees C, a finding which correlates with the recombination defect observed in vivo and indicates that this activity is an intrinsic function of the recA protein . These results suggest that the recA protein plays a specific role in strand transfer during recombination and possibly in postreplication repair of damaged DNA.

Nucleic Acids Res, 1979 Jan, 6(1), 71 - 80
Origin and direction of replication of the bacteriocinogenic plasmid Clo DF13; Stuitje AR et al.; Cairn's type replicative intermediates of both the wildtype Clo DF13 plasmid and the copy mutant CLO DF13 cop3 were isolated by dye-buoyant density centrifugation . Replicative intermediates were linearized at the HpaI or Sa1I cleavage site, and examined with the electron-microscope . The data show that replication of both the Clo DF13 wild type plasmid and the Clo DF13 cop3 plasmid, initiates at about 2.8% on the physical map . Replication proceeds unindirectionally and counterclockwise on this map.

Nucleic Acids Res, 1979 Jan, 6(1), 371 - 83
The specificity of in vitro chromatin transcription; Crouse GF et al.; The in vitro transcription of chicken reticulocyte chromatin with E . coli RNA polymerase has been studied in several different ways . The amount of globin RNA sequences has been measured by hybridizing the transcript with globin cDNA; we show that under the proper conditions mercurated transcript RNA can be separated from endogenous RNA on sulfhydryl affinity columns . The amount of globin RNA in the transcript is approximately 20 fold greater than that from erythrocyte chromatin or reticulocyte DNA . Although these data could be used to support the hypothesis of specific transcription, we show by RNA/RNA self hybridization of the transcript (which is at least 50% symmetric) and by hybridization of the transcript to unique DNA in vast RNA excess that the bulk of the chromatin transcript differs little from the transcript of naked DNA . Several explanations for these apparently contradictory results are offered with the most likely one being compatible with random transcription of at least most of the sequences in the chromatin.

Nucleic Acids Res, 1979 Jan, 6(1), 181 - 93
Fluorescence studies of the accessibility of the 3' ends of the ribosomal RNAs in Escherichia coli ribosomes and subunits; Schreiber JP et al.; The accessibility of the 3'-ends of E . coli in various states has been probed by reaction, after periodate oxidation, with the fluorescent dye proflavine semicarbazide . Free oxidized 16S and 23S rRNAs each react with 2 equivalents of dye . The 23S rRNA is equally reactive in the 50S subunit and the 70S ribosome . The 16S RRNA 3'-end is accessible in the 30S subunit . In the intact 70S particle, periodate can reach the 3'-end of the 16S rRNA but the dye cannot . The 5S rRNA is relatively inaccessible to periodate oxidation or dye reaction in the 70S particle . Dye-labelled 16S rRNA will reconstitute into 30S particles but they are inactive in polypeptide synthesis . This is apparently due to the inability of the 30S particles to form tight complexes with 50S subunits . Iodide quenching studies indicate that the environment of the 3'-end of 16S rRNA in the 30S particle is different from that of the free rRNA.

Nucleic Acids Res, 1979 Jan, 6(1), 111 - 37
The interaction of RNA polymerase and lac repressor with the lac control region; Schmitz A et al.; We have examined the interactions of lac repressor and RNA polymerase with the DNA of the lac control region, using a method for direct visualization of the regions of DNA protected by proteins from DNAase attack . The repressor protects the operator essentially as reported by Gilbert and Maxam (1) with some small modifications . However, the evidence reported here concerning the binding of RNA polymerase to the DNA of the promoter mutant UV5 indicates that : 1) the RNA polymerase molecule binds asymmetrically to the promoter DNA, 2) RNA polymerase protects DNA sequences to within a few bases of the CAP binding site, suggesting direct interaction between polymerase and the CAP protein at this site, 3) RNA polymerase still binds to the promoter when repressor is bound to the operator, but fails to form the same extensive complex.

Mikrobiologiia, 1979 Jan-Feb, 48(1), 149 - 52
{Effect of temperature on the viability of Escherichia coli strains in seawater}; Alton LV et al.; The survival and growth of E . coli strains were studied at different temperatures of sea water . The bacterial number for serotypes 055 and 078 was found to increase with a decrease in temperatue of sea water to 5 degrees C . The bacteria of serotype 015 did not grow in sea water whereas those of serotype 0115 were capable of growth only at 20 and 15 degrees C . The bacteria were able to survive from 4 to 98 days depending on the temperature of water and the strain of E . coli.

J Environ Pathol Toxicol, 1979 Jan-Feb, 2(3), 751 - 65
Toxicity studies with decamethrin, a synthetic pyrethroid insecticide; Kavlock R et al.; Decamethrin is a synthetic pyrethroid insecticide that has been under investigation by the World Health Organization for use in some vector control programs . Decamethrin proved to be a highly toxic pyrethroid ester . The acute LD50 for adult female rats was 31 mg/kg by the oral route and 4 mg/kg by the intravenous route of administration . The LD50 was observed to be sex and age dependent, with higher values recorded for weanlings and males . Initial signs of decamethrin poisoning include profuse salivation and convulsive movements . Weakness, dyspnea, anorexia and staining of the fur were observed beyond the first day following compound administration . Absorption of decamethrin was rapid by the inhalation route and minimal by the dermal route of administration . No evidence of teratogenic activity was found in rats or mice at dose levels that produced marked maternal toxicity, and no persistent toxicity was observed in neonatal rats that received perinatal exposure to decamethrin . No mutagenic activity was detected in three different in vitro assays, with or without metabolic activation.

J Int Med Res, 1979, 7(1), 100 - 5
Multicentre study of 'Flagyl' in the prevention of post-operative anaerobic infection; Goulton J et al.; In a study carried out with 565 patients undergoing gynaecological and general surgical procedures, metronidazole ('Flagyl') was used pre- and post-operatively and the incidence of post-operative infection, particularly that due to anaerobic organisms, was recorded . This was not a controlled study but, by comparison with other series, it would appear that the use of oral metronidazole had substantially reduced the likelihood of supervention of anaerobic sepsis . It is probable that the use of intravenous metronidazole therapy would have reduced the incidence of anaerobic sepsis still further had this preparation been available at the time.

Chemotherapy, 1979, 25(1), 5 - 8
In vitro activity of sulphonamides as a function of their molar refractivity; Kaliszan R et al.; A significnat correlation has been found between the in vitro activity of 16 commonly employed sulphonamides and their molar refractivity . The molar refractivity has been shown to be a superior parameter for the description of the activity of sulphonamides than the sum of electronegativities of atoms making up a heterocyclic substituent in the sulphonamide molecule and molecular weight of the substituent.

Cell, 1979 Jan, 16(1), 191 - 200
Length-independent separation of DNA restriction fragments in two-dimensional gel electrophoresis; Fischer SG et al.; When double helical DNA is exposed to conditions favoring partial melting in polyacrylamide gels, its electrophoretic mobility undergoes a sharp cooperative transition, resulting in a large reduction in mobility . In the present experiments, where the transition is effected at a uniform temperature of 60 degrees C in a concentration gradient of a urea-formamide mixture, each Eco RI fragment of lambda or E . coli DNA exhibits the mobility transition at a characteristic concentration of the denaturant . The sudden retardation of fragments moving toward higher denaturant concentration in the gradient results in a pattern of sharpened zones in order depending upon nucleotide sequence, rather than size, and only very slightly dependent upon the time after the last fragment has been retarded . When combined with length-dependent electrophoresis in agarose in the perpendicular direction, this system provides a two-dimensional separation of fragments . The resolving power of the system is demonstrated by the clear resolution of over 250 fragments of the Eco RI digest of E . coli DNA . Corresponding fragments from an isogenic lambda lysogen of E . coli are found in the same positions, and additional fragments unique to the lysogen are evident.

Cell, 1979 Jan, 16(1), 123 - 9
Mu insertion duplicates a 5 base pair sequence at the host inserted site; Allet B; Nucleotide sequences were analyzed across the two ends of lysogenic Mu DNA . These ends were cloned separately in lambdapMu hybrid particles that derived from a single Mu lysogen in the lac Z part of lambdaplac5 . The obtained data imply that Mu lysogenization was associated with the duplication of 5 base pairs present in lac DNA at the Mu insertion site . As a result of this duplication, Mu DNA is flanked by two copies of five identical base pairs oriented as direct repeats . A similar conclusion has been obtained independently by other investigators with the use of a different Mu lysogen (D . Kamp and R . Kahmann, personal communication) . Thus Mu insertion seems to have a striking similarity to typical IS-mediated insertions that were found to be associated with a short DNA duplication at the target site.

Cell, 1979 Jan, 16(1), 111 - 21
In vitro transcripts from the rrn B ribosomal RNA cistron originate from two tandem promoters; Glaser G et al.; The functional structure of the promoter region of a bacterial ribosomal operon is analyzed by in vitro transcription of linear DNA fragments derived from the hybrid Col EI plasmid pGG1 . This plasmid contains the promoter region of the rrn B ribosomal cistron present in the lambdarifd18 . When transcripts arising from this promoter region are terminated by restriction endonuclease cleavage of DNA, two RNA chains are resolved by gel electrophoresis that differ in length by about 100 bases . Evidence is presented indicating that these two transcripts arise from different initiation sites, each directing tandem transcription on the sense strand of the early portion of the ribosomal cistron.

Biokhimiia, 1979 Jan, 44(1), 130 - 41
{Isolation and properties of DNA-cytosine-methylase I from Escherichia coli MRE 600}; Nesterenko VF et al.; DNA-cytosine-methylase I was isolated and purified to homogeneity . The yield made up to about 30% of total activity . The enzyme molecular weight as determined by centrifugation in a sucrose gradient, by gel filtration and by electrophoresis in polyacrylamide gel in the presence of sodium dodecyl sulfate was found to be 45,000 . The Michaelis constant was 1,8 . 10(-6) M for SAM and 2 . 10(-4) M for DNA . DNA-cytosine-methylase I modifies phage lambda DNA in 60 sites . This modification does not protect DNA from the effects of restriction endonucleases HpaII and BsuRI . The enzyme methylates DNA in the nucleotide sequence: 5'...Pur-MC-C-G-G-Pyr...3'.

J Bacteriol, 1979 Jan, 137(1), 92 - 104
Structural and functional analysis of cloned DNA segments containing the replication and incompatibility regions of a miniplasmid derived from a copy number mutant of NR1; Taylor DP et al.; A 1.45-megadalton segment of DNA cloned from a miniplasmid derived in vivo from a copy number mutant of the R plasmid NR1 has been shown to contain all functions essential for incompatibility and autonomous plasmid replication in Escherichia coli . Specific endonuclease cleavage sites within this DNA segment that localize functions required for replication have been mapped . A 0.45-megadalton fragment that specifies the FII incompatibility of NR1 has been identified within the replication region, and DNA fragments containing this incompatibility region, but lacking other functions required for replication, have been cloned.

J Bacteriol, 1979 Jan, 137(1), 694 - 6
Accumulation of peptidyl tRNA is lethal to Escherichia coli; Menninger JR; A mutant strain of Escherichia coli with temperature-sensitive peptidyl-tRNA hydrolase grows at 30 degrees C but, when shifted to 40 degrees C, dies at rates affected by physiological, pharmacological, and genetical perturbations . The rate of killing correlates with the relative accumulation of peptidyl-tRNA, suggesting that it is responsible for the death of the cells.

J Bacteriol, 1979 Jan, 137(1), 692 - 3
Simple method for identification of plasmid-coded proteins; Sancar A et al.; Proteins encoded by plasmid DNA are specifically labeled in UV-irradiated cells of Escherichia coli carrying recA and uvrA mutations because extensive degradation of the chromosome DNA occurs concurrently with amplification of plasmid DNA.

J Bacteriol, 1979 Jan, 137(1), 673 - 6
Method for isolating restriction- and modificationless mutants of Escherichia coli K-12; Del Giudice L; A simple method is described for the selection and isolation of restriction- and modificationless mutants in Escherichia coli K-12 by using the following properties: (i) the temperature-sensitive repressor activity of phage lambdacI857; (ii) a mutant of lambda phage defective in integration and the establishment of repression (lambdab2cI); (iii) a virulent lambda phage insensitive to the repressor activity . The final yield of spontaneously arising rk-mk+ and rk-mk- mutants from stationary-phase cultures was about 5% of the surviving cells.

J Bacteriol, 1979 Jan, 137(1), 658 - 60
rorA mutation of Escherichia coli K-12 affects the recB subunit of exonuclease V; Glickman BW; The ATP-dependent nuclease, exonuclease V, of Escherichia coli plays an important role in repair and recombination . The enzyme is composed of two subunits, one of which is the product of the recB and recC genes . In this communication it is shown by mapping and complementation experiments that the rorA mutation, which results in radiation sensitivity but not the loss of recombination ability, is an allele of the recB gene.

J Bacteriol, 1979 Jan, 137(1), 584 - 94
Organization of genes for transcription and translation in the rif region of the Escherichia coli chromosome; Yamamoto M et al.; The lambdarifd18 transducing phage is known to carry several genes for components of transcriptional and translational machineries; these genes are clustered in the rif region at 88 min on the Escherichia coli genetic map . They include a set of genes for rRNA's (rrnB), a gene for spacer tRNA, tRNA2Glu (tgtB), one of the two genes for EF-Tu (tufB), genes for four ribosomal proteins (rplK, A, J, and L), genes for the beta and beta' subunits of RNA polymerase (rpoB and rpoC), and genes for three tRNA's (tyrU, gluT, and thrT) . An additional tRNA gene (subsequently identified as thrU by Landy and his co-workers) and a gene for a protein (protein U) with unknown functions were found to be carried by lambdarif d18 . We analyzed the organization of these genes by using various deletion and hybrid phages derived from lambdarif d18 and lambdarif d12, a phage related to lambdarif d18 . The expression of various genes was examined in UV-irradiated cells infected with these transducing phages . Two main conclusions were obtained . First, the four tRNA genes are not cotranscribed with the genes in rrnB, even though these tRNA genes are located close to the distal end of rrnB . Second, the four ribosomal protein genes are organized into two separate transcriptional units; rplK and A are in one unit and rplJ and L are in the second unit . The first group of genes was shown to have a promoter separate from that for tufB or protein U . The second group of genes shares the promoter with rpoB and C, as described in a separate paper (M . Yamamoto and M . Nomura, Proc . Natl . Acad . Sci . U.S.A., 75:3891--3895) . These and other results described in this paper show that the genes are organized in the following order: promoter, genes in rrnB; promoter, thrU, tyrU, (promoter?) glyT, thrT; (promoter?) tufB; promoter, a gene for protein U; promoter, rplK, rplA; promoter, rplJ, rplL, rpoB, rpoC.

J Bacteriol, 1979 Jan, 137(1), 574 - 83
Localization of proteolytic activity in the outer membrane of Escherichia coli; MacGregor CH et al.; An enzyme in the cytoplasmic membrane, nitrate reductase, can be solubilized by heating membranes to 60 degrees C for 10 min at alkaline pH . A protease in the cell envelope has been shown to be responsible for this solubilization . The localization of this protease in the outer membrane was demonstrated by separating the outer membrane from the cytoplasmic membrane, adding back various forms of outer membrane protein to the cytoplasmic membrane, and following the increase in nitrate reductase solubilization with increasing amounts of outer membrane proteins . This solubilization is accompanied by the cleavage of one of the subunits of nitrate reductase and is inhibited by the protease inhibitor p-aminobenzamidine . Analysis of membrane proteins synthesized by cells grown in the presence of various amounts of p-aminobenzamidine revealed that p-aminobenzamidine affects the synthesis of the major outer membrane proteins but has little effect on the synthesis of cytoplasmic membrane proteins . When outer membrane is reacted with the protease inhibitor {3H}diisopropylfluorophosphate, a single protein in the outer membrane is labeled . Since the interaction with diisopropylfluorophosphate is inhibited by p-aminobenzamidine, it is suggested that this single outer membrane protein is responsible for the in vitro solubilization of nitrate reductase and the in vivo processing of the major outer membrane proteins.

J Bacteriol, 1979 Jan, 137(1), 568 - 73
Isolation and characterization of amber mutations in the lexA gene of Escherichia coli K-12; Pacelli LZ et al.; We describe the isolation and characterization of amber mutations in the lexA gene of Escherichia coli K-12 . These mutations, designated spr(Am), were isolated and characterized in a lexA tif sfi genetic background . They abolished the sensitivity of the strain to UV light and resulted in high rates of synthesis of recA protein . Phage lambda+ failed to lysogenize the strains as observed with similar strains carrying non-amber spr mutations described previously, thereby indicating a constitutive expression of the phage induction pathway . Introduction of an amber suppressor mutation into a strain bearing the spr(Am) mutation restored expression of the LexA mutant phenotype . We conclude that spr mutations either inactivate or prevent synthesis of the lexA gene product and that loss of this product results in constitutive expression of the E . coli induction system in the tif sfi genetic background.

J Bacteriol, 1979 Jan, 137(1), 502 - 6
ColE1 hybrid plasmids for Escherichia coli genes of glycolysis and the hexose monophosphate shunt; Thomson J et al.; The Clarke-Carbon clone bank carrying ColE1-Escherichia coli DNA has been screened by conjugation for complementation of glycolysis and hexose monophosphate shunt mutations . Plasmids were identified for phosphofructokinase (pfkA), triose phosphate isomerase (tpi), phosphoglucose isomerase (pgi), glucose-6-phosphate dehydrogenase (zwf), gluconate-6-phosphate dehydrogenase (gnd), enolase (eno), phosphoglycerate kinase (pgk), and fructose-1,6-P2 aldolase (fda) . Enzyme levels for the plasmid-carried gene ranged, for the various plasmids, from 4- to 25-fold the normal level.

J Bacteriol, 1979 Jan, 137(1), 469 - 73
Five different enzymatic activities are associated with the multienzyme complex of fatty acid oxidation from Escherichia coli; Pramanik A et al.; The purified multienzyme complex of fatty acid oxidation from Escherichia coli was found to possess 3-hydroxyacyl-coenzyme A (CoA) epimerase and cis-delta3-trans-delta2-enoyl-CoA isomerase activities in addition to the previously identified enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and 3-ketoactyl-CoA thiolase activities . Evidence is presented in support of the proposed association of all five enzyme activities with one protein which apparently is composed of two types of subunits and which can exist in several aggregated forms . The five component enzymes of the complex were rapidly inactivated by tris(hydroxymethyl)aminomethane, whereas they remained active in the presence of potassium phosphate.

J Bacteriol, 1979 Jan, 137(1), 447 - 55
Direct determination of the properties of peptide transport systems in Escherichia coli, using a fluorescent-labeling procedure; Payne JW et al.; A direct study of peptide uptake by Escherichia coli was made using a fluorescent procedure . After incubation with the bacteria, peptides remaining in the medium were dansylated, separated chromatographically, and quantitated from their fluorescent intensities and/or from their incorporated radioactivity when tritiated dansyl derivatives were prepared . Peptide uptake was apparently not regulated and proceeded continuously until complete, with the absorbed peptides undergoing rapid intracellular hydrolysis and the excess amino acid residues leaving the cell . Thus, peptide uptake and amino acid exodus occur concurrently . However, peptidase-resistant substrates, e.g . triornithine and glycylsarcosine, which can be similarly estimated in cell extracts, were accumulated about 1,000-fold . The influence of amino acid composition and chain length on rates of transport was assessed . Different strains of E . coli showed variability in their rates of di- and oligopeptide transport . With respect to energy coupling, both the di- and oligopeptide permeases behaved like shock-sensitive transport systems.

J Bacteriol, 1979 Jan, 137(1), 44 - 50
Methylation-dependent DNA synthesis in Escherichia coli mediated by DNA polymerase I; Lark C; An in vitro system was used to study DNA synthesis in lysates of Escherichia coli cells which had been grown in the presence of ethionine . Such lysates showed a reduced capacity to incorporate {3H}TTP into high-molecular-weight material . Activity could be restored by incubation with S-adenosyl methionine and ATP . S-adenosyl methionine-reactivated TTP incorporation required the presence of DNA polymerase I, ATP, and all four deoxyribonucleotide triphosphates . DNA polymerase III was not required.

J Bacteriol, 1979 Jan, 137(1), 365 - 73
Escherichia coli K-12 mutants that allow transport of maltose via the beta-galactoside transport system; Shuman HA et al.; We have isolated mutants of Escherichia coli that have an altered beta-galactoside transport system . This altered transport system is able to transport a sugar, maltose, that the wild-type beta-galactoside transport system is unable to transport . The mutation that alters the specificity of the transport system is in the lacY gene, and we refer to the allele as lacYmal . The lacYmal allele was detected originally in strains in which the lac genes were fused to the malF gene . Thus, as a result of gene fusion and isolation of the lacYmal mutation, a new transport system was evolved with regulatory properties and specificity similar to those of the original maltose transport system . Maltose transport via the lacYmal gene product is independent of all of the normal maltose transport system components . The altered transport system shows a higher affinity than the wild-type transport system for two normal substrates of the beta-galactoside transport system, thiomethyl-beta-D-galactoside and o-nitrophenyl-beta-D-galactoside.

J Bacteriol, 1979 Jan, 137(1), 281 - 4
Recipient competence in F'lac matings of Escherichia coli K-12; Cullum J et al.; We studied recipient mating ability in the presence of excess F'lac donors . Ninety-five percent of recipients were able to receive F'lac in 30-min matings . Competition between an F'-lac donor and an F'lac traI donor, which mobilized a ColE1 derivative (pML2), showed that each recipient mated with an average of two to three donors in 30 min . Experiments in which the competing donor was added at different times showed that some competition occurred throughout the 30-min mating period, which suggested that aggregate formation was spread over this time.

J Bacteriol, 1979 Jan, 137(1), 234 - 42
Pyrimidine dimer excision in Escherichia coli strains deficient in exonucleases V and VII and in the 5' leads to 3' exonuclease of DNA polymerase I; Chase JW et al.; An isogenic series of Escherichia coli strains deficient in various combinations of three 5' leads to 3' exonucleases (exonuclease V, exonuclease VII, and the 5' leads to 3' exonuclease of DNA polymerase I) was constructed and examined for the ability to excise pyrimidine dimers after UV irradiation . Although the recB and recC mutations (deficient in exonuclease V) proved to be incompatible with the polA(Ex) mutation (deficient in the 5' leads to 3' exonuclease of DNA polymerase I), it was possible to reduce the level of the recB,C exonuclease by the use of temperature-sensitive recB270 recC271 mutants . It was found that, by employing strains deficient in exonuclease V, postirradiation DNA degradation could be reduced and dimer excision measurements could be facilitated . Mutants deficient in exonuclease V were found to excise dimers at a rate comparable to that of the wild type . Mutants deficient in exonuclease V and the 5' leads to 3' exonuclease of DNA polymerase I are slightly slower than the wild type at removing dimers accumulated after doses in excess of 40 J/m2 . However, although strains with reduced levels of exonuclease VII excised dimers at the same rate as the wild type, the addition of an exonuclease VII deficiency to a strain with reduced levels of exonuclease V and the 5' leads to 3' exonuclease of DNA polymerase I caused a marked decrease in the rate and extent of dimer excision . These observations support previous indications that the 5' leads to 3' exonuclease of DNA polymerase I is important in dimer removal and also suggest a role for exonuclease VII in the excision repair process.

J Bacteriol, 1979 Jan, 137(1), 129 - 36
Characterization of mutationally altered dihydropteroate synthase and its ability to form a sulfonamide-containing dihydrofolate analog; Swedberg G et al.; Among spontaneous mutants of Escherichia coli selected for resistance against sulfonamides, thermosensitive strains were found . These were shown to possess a changed dihydropteroate synthase (EC 2.5.1.15), which had a substantially higher Km value for its normal substrate, p-aminobenzoic acid, and an about 150-fold higher Km for sulfonamides . The mutationally changed dihydropteroate synthase was found to be thermosensitive by in vitro assays . The thermosensitivity was used as an enzyme marker to demonstrate the complex formation between 2-amino-4-hydroxy-6-pyrophosphorylmethyl pteridine and sulfonamides by partially purified dihydropteroate synthase . The formation of folate from 2-amino-4-hydroxy-6-pyrophosphorylmethyl pteridine and p-aminobenzoylglutamic acid by dihydropteroate synthase was found to be very sensitive to inhibition by sulfonamides and very inefficient with the mutationally changed enzyme.

J Bacteriol, 1979 Jan, 137(1), 115 - 23
Expression of RNA polymerase and ribosome component genes in Escherichia coli mutants having conditionally defective RNA polymerases; Little R et al.; The expression of the genes coding for the beta and beta' subunits of RNA polymerase, ribosomal RNA, ribosomal proteins, and beta-galactosidase was investigated in strains carrying conditionally lethal mutations affecting either RNA polymerase core assembly or RNA polymerase enzyme activity . The mutant strain XH56 produces a temperature-sensitive beta' subunit and at 42 degrees C is defective in RNA chain initiation; consequently, little or no transcription occurs at the restrictive temperature . A partial restriction, produced by shifting the strain to 39 degrees C, resulted in a rapid fivefold increase in the transcription of the rpoB and C genes and in the synthesis of the beta- and beta'-subunit proteins for which they code . The RNA polymerase assembly-defective strains A2R7 and TS4 exhibited a 1.5- to 2-fold increase in the transcription of the rpoB and C genes and in the synthesis of beta- and beta-subunit proteins after prolonged restriction . These results demonstrate (i) that regulation of the synthesis of the beta- and beta-RNA polymerase subunits is under these conditions primarily transcriptional rather than translational, and (ii) that a stimulation of rpoB and C gene expression results from a restriction on RNA synthesis caused by either RNA polymerase inactivation or inhibition of its assembly . During restriction of the mutant strains, the transcription of the ribosome component genes exhibited patterns which were similar to transcription of the rpoB and C genes, supporting the evidence that genes coding for RNA polymerase are cotranscribed with ribosomal protein genes; transcription of the lacZ gene was observed to decrease concomitant with the stimulation of the rpoB and C genes.

Nutr Metab, 1979, 23(1), 26 - 37
Transcription of rat liver chromatin by Escherichia coli RNA polymerase: template properties after protein restriction; Andersson GM et al.; Transcription was determined in liver chromatin from rats fed for 6 days, an optimal (20%) or suboptimal (3%) amount of high-quality protein . Transcription by Escherichia coli RNA polymerase (EC 2.7.7.6) was lower after prolonged incubation with chromatin from rats fed 3% as compared with 20% protein . Differences were detected in the transcripts of the two types of chromatin after analysis by sucrose density gradient centrifugation . But no measurable differences were found in the melting profiles at low ionic strength of the two chromatin preparations . Transcription per milligram chromatin DNA was 25-fold higher using E . coli RNA polymerase instead of rat liver RNA polymerase II . The use of UTP as radioactive precursor in the absence of ATP, GTP and CTP resulted in a low labelling of RNA . One {lambda32P}UTP nucleotide was incorporated/8 UMP nucleotides . The product obtained was sensitive to ribonuclease treatment . In the presence of ATP, GTP and CTP {lambda-32P}UTP nucleotide incorporation was reduced and that of UMP nucleotide was increased giving a ratio of 1:188.

J Urol, 1979 Jan, 121(1), 129 - 30
Transrectal seminal vesiculography; Meyer JJ et al.; Lesions of the seminal vesicle can be evaluated by the transrectal needle approach . Biopsy, aspiration of contents for culture and cytology, injection of contrast medium for x-ray and drainage of cysts or abscesses can be done with this approach.

Adv Shock Res, 1979, 2, 219 - 32
Lidocaine treatment following baboon endotoxin shock improves survival; Fletcher JR et al.; Baboons treated with lidocaine (2 mg/kg/hr) after shock from endotoxin were compared to untreated controls in an LD70 E coli endotoxin (4 mg/kg) model . Survival, systemic and pulmonary arterial pressures, cardiac output, white blood cell and platelet counts, blood gases and arterial and mixed venous PGE and PGF 2 alpha levels were determined . Baboons receiving lidocaine had a better (P less than 0.05) survival at 72 hours than the controls . Circulatory function was improved with lidocaine; however, white blood cell and platelet counts, blood gases, and the prostaglandin release were similar in both groups . The mechanism by which lidocaine improves survival in baboon endotoxin shock appears to be unrelated to its effects on white blood cells, platelets, or the prostaglandin release.

Nucleic Acids Res, 1979 Jan, 6(1), 275 - 87
In vitro DNA dependent synthesis of globin RNA sequences from erythroleukemic cell chromatin; Reff ME et al.; Murine erythroleukemic cells in culture accumulate cytoplasmic globin mRNA during differentiation induced by dimethyl sulfoxide (DMSO)1 . Chromatin was prepared from DMSO induced erythroleukemic cells that were transcribing globin RNA in order to determine whether in vitro synthesis of globin RNA sequences was possible from chromatin . RNA was synthesized in vitro using 5-mercuriuridine triphosphate and exogenous Escheria coli RNA polymerase . Newly synthesized mercurated RNA was purified from endogenous chromatin associated RNA by affinity chromatography on a sepharose sulfhydryl column, and the globin RNA sequence content of the mercurated RNA was assayed by hybridization to cDNA globin . The synthesis of globin RNA sequences was shown to occur and to be sensitive to actinomycin and rifampicin and insensitive to alpha-amanitin . In contrast, synthesis of globin RNA sequence synthesis was not detected in significant amounts from chromatin prepared from uninduced erythroleukemic cells, nor from uninduced cell chromatin to which globin RNA was added prior to transcription . Isolated RNA:cDNA globin hybrids were shown to contain mercurated RNA by affinity chromatography . These results indicated that synthesis of globin RNA sequences from chromatin can be performed by E . coli RNA polymerase.

Acta Physiol Lat Am, 1979, 29(1), 81 - 5
Transcriptional features of fractionated human breast tumor chromatin; Thierbach LI et al.; By means of controlled mechanical shearing it was possible to fractionate human breast tumor chromatin in "active" and "inactive" species, according to their in vitro template activity, using Escherichia coli RNA polymerase . The "active" molecules can be resolved in three well defined regions in an exponential sucrose gradient, showing approximately 300 times the efficiency for synthesizing ribonucleic acid, relative to the chromatin which migrated fastest . This technique could provide the initial tool to isolate eu-and heterochromatin from native human chromatin.

Acta Physiol Acad Sci Hung, 1979, 54(3), 257 - 63
Central and peripheral adrenergic mechanisms in endotoxin fever and newborn guinea pigs; Szekely M; In 0--3 day-old guinea pigs cerebroventricular pretreatment with alpha-methyl-p-tyrosine failed to modify the course of fever induced by E . coli endotoxin administration into the cerebral ventricles . Central or intraperitoneal administration of phentolamine or central administration of propranolol were also ineffective . Intraperitoneal propranolol, however, prevented both the first and the second temperature rise after endotoxin, while the transient fall in temperature that usually occurs between them still ensued . Central noradrenergic mechanisms seem to play, at most, a minor role in the mediation of endotoxin fever, while the integrity of peripheral beta adrenergic receptors is indispensable for the febrile response to occur.

Environ Mutagen, 1979, 1(4), 347 - 52
Substrate-specificity of uvr excision repair; Murray ML; The substrate specificity of the uvr endonuclease, the product of the uvrA, uvrB, and uvrC genes is reviewed . It is suggested that the relatively well-defined substrate specificity of this repair enzyme is useful as a guide in determining the nature of the DNA-lesion caused by a given mutagen.

Ann Biol Clin (Paris), 1979, 37(5), 259 - 70
{Hereditary abnormalities of galactose metabolism: diagnosis and biochemical supervision (author's transl)}; Brivet M et al.; The authors define the main stages of the biochemical study of hereditary abnormalities of galactose metabolism . They review laboratory examinations for detection, enzyme examinations which provide the diagnostic proof, further examinations which permit one to follow the course and efficacy of a galactose-free diet, the demonstration of genetic variants, the technics of antenatal diagnosis and routine neonatal detection.

Mol Gen Genet, 1979, 177(1), 65 - 72
A restriction enzyme cleavage map of Tn5 and location of a region encoding neomycin resistance; Jorgensen RA et al.; This paper reports a cleavage site map of Tn5 for restriction enzymes BamHI, Bg/I, Bg/II, Hind II, HindIII, HpaI, Sa/I, Aval, SmaI, XhoI, PstI, PvuII, HaeII and HaeIII that was determined by the analysis of restriction enzyme cleavage patterns of ColEl, two independent ColEl::Tn5 plasmids, and a ColEl::Tn5 deletion derivative . Ba/I, EcoRI, KpnI, and PvuI do not cleave Tn5 . Construction and analysis of in vitro-generated deletions of a ColEl::Tn5 plasmid limit the sequences encoding neomycin resistance to a 1500-base-pair-long segment of Tn5 . Insertion of DNA at a Bg/II site within this segment results in loss of the neomycin resistance phenotype . Since this Bg/II site lies in an inverted repeat region, sequences within this repeat seem to be involved in the expression of neomycin resistance.

Mol Gen Genet, 1979, 177(1), 169 - 75
DNA supercoiling and transcription in Escherichia coli: influence of RNA polymerase mutations; Mirkin SM et al.; Coumermycin A1, a specific inhibitor of DNA gyrase, differentially changes the spectrum of proteins synthesized in wild type E . coli cells but has no effect on the protein spectrum in mutant cells with coumermycin-resistant DNA gyrase . The rpoB265 mutation affecting RNA polymerase decreases the coumermycin A1-sensitivity of bacteria while the rpoC3 mutation increases it . The interaction of wild type and mutant RpoB265 RNA polymerases with ColEl plasmid DNA in vitro is differently affected by DNA supercoiling . No such differences are observed in the case of RpoC3 RNA polymerase . The results suggest that template supercoiling may have a substantial effect on transcription in vivo, an effect which, in some cases, depends on the properties of RNA polymerase.

Mol Gen Genet, 1979, 177(1), 163 - 8
In vitro insertion of the lambda attachment site into the plasmid RP4; Pastrana R et al.; The region of the phage lambda chromosome containing the attachment site (P.P') and the genes int and xis, excised by the action of endonuclease R.EcoRI, has been inserted into the unique site for that enzyme on the promiscuous conjugative plasmid, RP4, generating the recombinant plasmid RP4att lambda . Transformants containing the hybrid plasmid were recognised by their ability to allow efficient lysogenization by phage lambda b2 (Weil and Signer, 1968; Echols et al., 1968) containing the mutant attachment site delta . P' . The construction and properties of the hybrid plasmid RP4att lambda are described.

Mol Gen Genet, 1979, 177(1), 113 - 20
Replication of the colicin E1 plasmid in extracts of Escherichia coli: uncoupling of leading strand from lagging strand synthesis; Staudenbauer WL et al.; The replication of the ColEl plasmid was studied in extracts from E . coli dnaG mutants . It was found that the synthesis of the complementary strands of ColEl DNA can be carried out in these extracts in two consecutive steps: (1) synthesis of the leading L strand independent of the dnaG function, and (2) synthesis of the lagging H strand depending upon addition of wild-type dnaG protein . In contrast to L strand synthesis, the latter reaction is insensitive to rifampicin and novobiocin . Both synthetic pathways are however blocked by antiserum directed against dnaB protein . This indicates an additional role of the dnaB protein in duplex DNA replication besides assisting the dnaG protein in the priming of lagging strand synthesis . The T7 gene-4 protein acting in conjunction with T7 DNA polymerase can substitute for both the function of the dnaB and dnaG protein . It is concluded that plasmid replication proceeds by a semi-discontinuous mechanism.

Biochimie, 1979, 61(10), 1151 - 60
Isolation and identification of mutants constitutive for aspartokinase III synthesis in Escherichia coli K 12; Boy E et al.; We devised a procedure in order to isolate, in Escherichia coli, constitutive mutants for aspartokinase III synthesis, the first enzyme of the lysine regulon . It consists of the introduction of a limiting step in lysine biosynthesis, by the use of the partial suppression of a nonsense mutation . For the first time we could isolate many constitutive mutants . Their characteristics (cotransduction with the lysC structural gene; no effect on the synthesis of other enzymes of the regulon; cis-dominance) lead to classify these mutations as operator-type . The fact that no repressor mutations could be isolated is discussed.

Cold Spring Harb Symp Quant Biol, 1979, 43 Pt 1, 63 - 7
DNA helicases; Kuhn B et al.; In summary, we postulate that DNA unwinding and ATP dephosphorylation are coupled in different ways, depending on whether the fibrous ATPase or one of the globular ATPases provides the catalytic agent . Unanswered is the question of whether there is stoichiometry of ATP utilization during the unwinding of a duplex, and unsolved is the role of the individual enzyme in the cell.

Cold Spring Harb Symp Quant Biol, 1979, 43 Pt 1, 345 - 8
DNA-dependent ATPases from Escherichia coli K12; Richet E et al.; Four DNA-dependent ATPases have been isolated from E . coli extracts . ATPases I and III, both sensitive to NEM, require denatured DNA but differ in their heat sensitivity, elution from DEAE-cellulose, and sedimentation coefficient . ATPases II and IV are both resistant to NEM . ATPase II requires partially denatured DNA, whereas ATPase IV can be stimulated by SS DNA . ATPase I is a DNA-unwinding enzyme; ATPase II may be involved in recombination.

Nucleic Acids Res, 1979, 6(5), 1863 - 7
Genome organization of retroviruses . III . Restriction endonuclease cleavage maps of mouse sarcoma virus double-stranded DNA synthesized in vitro; Verma IM; Genome length complementary DNA (cDNA) transcripts were synthesized in vitro by using purified virions of a cloned isolate of mouse sarcoma virus (MSV Clone 124) . The cDNA transcripts were converted to double-stranded form by utilizing DNase-digested calf thymus DNA primers and E . coli DNA polymerase I . Restriction endonucleases Sal I, Hind III, Hpa I, Bgl II and Xba I were found to cleave the MSV double-stranded DNA once to generate two fragments, whereas restriction endonucleases Bgl I and Hae II cleaved twice to generate three fragments . Restriction endonucleases E . coli RI and Bam HI did not cleave MSV double-stranded DNA . The order of the restriction fragments was determined in relation to the 5' and 3' ends of the genomic RNA.

J Lab Clin Med, 1979 Jan, 93(1), 25 - 31
Evidence that endotoxin is the cyclic 3':5'-GMP--promoting factor in erythropoietin preparations; Graber SE et al.; Since Ep preparations are contaminated with endotoxin, the possibility that the latter might be the factor in crude Ep which increases cGMP levels in rat fetal liver cells was examined . Endotoxin produced a striking elevation of cGMP in rat fetal liver cells without affecting cAMP levels or heme synthesis . Absorption with Limulus lysate of more than 99% of the endotoxin in a crude Ep preparation caused a parallel decrease in the cGMP-promoting activity without reduction of heme synthetic potency . It is concluded that endotoxin is the component of crude Ep which increases cGMP levels in rat fetal liver . The precise role of elevated cGMP in the action of endotoxin on cells and the universality of this effect remain to be determined.

Acta Physiol Acad Sci Hung, 1979, 54(3), 265 - 76
Endotoxin fever in the newborn kitten . The role of prostaglandins and monoamines; Szekely M; In 5--10 day-old kittens at thermoneutral environmental temperature cerebroventricular injections of 10 microgram serotonin or noradrenaline caused hyperthermia and hypothermia, respectively . Central injections of 20 and 200 ng prostaglandin E1 induced hyperthermia . Monophasic fever followed the cerebroventricular injections of 0.2 or 0.002 microgram E . coli endotoxin, both in thermoneutral and moderately cool environments . In kittens pretreated with para-chlorophenylalanine (PCPA) the endotoxin induced rise in body temperature was attenuated within 60 to 90 min after the endotoxin . Indomethacin pretreatment prevented the first part of the febrile response and only a slight temperature rise occurred after a long latency . Central injections of phentolamine did not modify the fever response, while centrally applied propranolol modified the fever course so that it resembled that seen in PCPA treated kittens . The central mediation of endotoxin fever in the kitten is complex, despite that the pattern of the temperature change is simple (monophasic) . Arachidonic acid metabolites and serotonin of the central nervous system may be involved in the reaction, while the activation of central noradrenergic mechanisms does not seem to be indispensable for the response . The changes in mediators are similar to those in newborn guinea pigs, although the fever course is different in the two species.

Environ Mutagen, 1979, 1(1), 65 - 78
A colorimetric assay of lysogenic induction designed for screening potential carcinogenic and carcinostatic agents; Elespuru RK et al.; Simple, rapid colorimetric tests for lysogenic induction (the derepression of a latent bacterial virus) are described . A quantitative test and a more rapid semiquantitative test are based on the assay of the beta-galactosidase synthesized from lacZ gene fused to an operon under lambda repressor control . These biochemical "inductests" are suitable for screening programs designed to detect agents that damage DNA and that are of potential interest in carcinogenesis and cancer chemotherapy.

J Hyg Epidemiol Microbiol Immunol, 1979, 23(3), 261 - 5
Effect of experimental magnetic storm on the production of lambda phage; Chervinets VM; 1 . Sharp fluctuation of the intensity of the vertical component of the MF amounting to +/- 0.1 Oe changing the sign over each 3 min causes variability of both lysogenic and indicator strains of E . coli . This testifies to an extremely low threshold of their magnetic susceptibility and to biological importance of fluctuations of natural parameters of the geomagnetic field as an ecological factor of the environment . 2 . A change in the intensity of the vertical component of the MF, not any higher than +/-0.1 Oe, inhibits phage production in the lysogenic system of E . coli K = 12 lambda and is also reflected in the morphological peculiarities of negative phage colonies as well as in the phage-susceptibility of the E . coli indicator strain.

Genetika, 1979, 15(1), 32 - 40
{Effect of the dose of ptsI- and ptsH-genes on carbohydrate transport and regulation of lac-operon activity in Escherichia coli K-12}; Gershanovich VN et al.; Phage Mu-1 cts61 was used for transposition of pts1 and ptsH genes . The received F'-factors AUF2 and AUF3 carry short fragments of the bacterial chromosome . Merodiploid strains with double pts genes were selected in sexduction crosses with the appropriate recA recipients . Effect of the gene dose was not registered in pts+/pts+ strains in the case of accumulation of the substrates of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) and in the case of bacterial growth in the presence of these carbohydrates . This indicates that the enzyme (enzymes) II of the PTS is the limiting step in the transpost process . Induction of beta-galactosidase and the growth on carbohydrates not transported via the PTS (maltose, lactose) were greatly reduced in pts mutant . Introduction of the pts+ allele with episome lead to the restoration of the two above processes . These data show that the phospho approximately HPr generating system of the PTS is directly (or in indirect manner) involved in the regulation of catabolite-sensitive operons . Glucose repression was markedly increased in pts+/pts+ merodiploids as compared with pts+/pts- ones and with pts+ bacteria . Possible mechanisms of this effect are discussed.

J Bacteriol, 1979 Jan, 137(1), 653 - 7
Genetic and physiological studies on the relationship between colicin B resistance and ferrienterochelin uptake in Escherichia coli K-12; McIntosh MA et al.; The Escherichia coli gene for the ferrienterochelin uptake and colicins B and D receptor protein is located at approximately 13 min, adjacent to or among genes for enterochelin biosynthetic enzymes . The two receptor functions (colicin and siderophore) are separable by mutation.

J Bacteriol, 1979 Jan, 137(1), 221 - 5
Requirement for membrane potential in active transport of glutamine by Escherichia coli; Plate CA; The effect of reducing the membrane potential on glutamine transport in cells of Escherichia coli has been investigated . Addition of valinomycin to tris(hydroxymethyl)aminomethane-ethylenediaminetetraacetic acid-treated E . coli cells in the presence of 20 mM exogenous potassium reduced the membrane potential, as measured by the uptake of the lipophilic cation triphenylmethylphosphonium, and caused a complete inhibition of glutamine transport . Valinomycin plus potassium also caused a rapid decrease in the intracellular levels of ATP of normal E . coli cells, but had little if any effect on the ATP levels of two mutants of E . coli carrying lesions in the energy-transducing ATP complex (unc mutants) . Yet both the membrane potential and the capacity to transport glutamine were depressed in the unc mutants by valinomycin and potassium . These findings are consistent with the hypothesis that both ATP and a membrane potential are essential to the active transport of glutamine by E . coli cells.

Arch Exp Veterinarmed, 1979, 33(4), 489 - 94
{Preliminary results of an atiepizootic field test using EDTA-Na extract vaccine from Escherichia coli strains pathogenic to swine in swine production industrial units}; Mochmann H et al.; An anti-epizootic field test was applied to industrialised pig farms in the region of Wroclaw, Poland, to test the effectiveness of a pentavalent EDTA (calcium disodium edetate)--sodium vaccine extracted from Escherichia coli strains with pathogenicity to swine . The vaccine had been received from a centre in Berlin-Buch, GDR . The vaccine failed to provide any protection, when orally applied to nursed piglets . However, both morbidity and mortality were reduced and, thus, an anti-epizootic effect on nursed piglets produced, when the vaccine had been injected intramuscularly to the pregnant mother animals, prior to farrowing . In weaned piglets morbidity was sucessfully reduced by both oral as well as intramuscular administration.

Nucleic Acids Symp Ser, 1979, (6), s47 - 50
Evolutionary considerations of DNA repair in relation to mutagenesis, teratogenesis and carcinogenesis; Kondo S; Living organisms have various mechanisms for repairing spontaneous and mutagen-induced damage in DNA . Mutagenesis, teratogenesis, and carcinogenesis are discussed in relation to DNA misrepair . The existence of highly efficient genetic mechanisms for tolerating environmental threats is argued from evolutionary viewpoints.

Vet Med Nauki, 1979, 16(6), 35 - 41
{Suitability of chemical neutralizers applied for disinfection control on commercial animal husbandry objects}; Bineva I et al.; A study on the effect of various neutralizers of the most widely spread means of disinfection applied in animal rearing was made . For that purpose twin lecytine was tested for quadruple ammonium compounds: twin--for phenolic compounds, natrium thiosulfate--for iodoformium and chlor-containing compounds, as well as natrium sulfite--for formalin . As test micro-organisms were used Staph . aureus Sg 511, E . coli 078, and Ps . aeruginosa . The investigations were performed after the suspension method with dilutions in geometrical progressions . It was established that for the disinfection by quadruple ammonium compounds 3% twin-80 plus 0.3% lecytine is suitable as neutralizer . In disinfection with phenolic compounds the 1% twin-80 solution gives good results . As neutralizer of formalin disinfection 2% natrium sulfite solution can be successfully used . For iodoformium disinfection or disinfection with chlor-containing compounds good neutralizing effect can be achieved by 1% solution of natrium thiosulfate.

Am J Pediatr Hematol Oncol, 1979 Fall, 1(3), 245 - 9
Activation of coagulation and disseminated intravascular coagulation in the newborn; Corrigan JJ Jr; Human newborns have certain hemostatic "deficiencies" which seem to be peculiar to this period of life, such as reduced factors II, VII, IX, X, XI, and XII, reduced antithrombin III levels, and reduced plasminogen levels . However, they are capable of activating the coagulation mechanism to elicit either the entity of disseminated intravascular coagulation or the occurrence of localized and diffuse thrombotic events . The mechanisms involved have yet to be defined . Evidence has been presented to suggest that preterm infants may manifest a variant form of disseminated intravascular coagulation in which thrombocytopenia is not present.

Scand J Immunol, 1979, 10(1), 81 - 6
Efficient conjugation of rabbit Fab' with beta-D-galactosidase from Escherichia coli; Yoshitake S et al.; An efficient procedure for the conjugation of rabbit Fab' with beta-D-galactosidase from Escherichia coli using N,N-o-phenylenedimaleimide is described . Thiol groups of Fab' were stabilized by the presence of ethylenediaminetetraacetate, and malemide groups were shown to be stable at pH 5 at 4 degrees C . The stability of thiol and maleimide groups enabled an efficient introduction of maleimide groups into Fab' and the average number of maleimide groups introduced into Fab' was 0.76 (range 0.73-0.79; n = 10) per molecule . As a result, 43.4% (range 41.3-46.9%; n = 6) of Fab' used could be conjugated with most of beta-D-galactosidase used . The average number of Fab' molecules conjugated per enzyme molecule was calculated to be 4.2 (range 4.0-4.6; n = 6) . Both the enzyme and antibody activities were well preserved in the conjugate . There was no self-coupling of Fab', although the enzyme was polymerized to some extent during the conjugation reaction . The enzyme activity and cross-link in the conjugate was stable at pH 6.0-7.0 at 4 degrees C for at least 3 months.

Nucleic Acids Res, 1979, 6(6), 2355 - 61
The conformational properties of ribosomal protein S1; Moore PB et al.; The proton NMR spectrum of S1 reveals that S1 has considerable tertiary structure in physiological buffers, but more structural flexibility than normal for globular proteins . S1's NMR spectrum is independent of the method of preparation.

Arch Exp Veterinarmed, 1979 Jan, 33(1), 47 - 52
{Preparation and testing of polyvalent EDTA-Na-extract vaccine from Escherichia coli strains pathogenic to Swine}; Austenat L et al.; Monovalent vaccines were prepared of E . coli strains with pathogenicity to swine by means of a technique described elsewhere . A polyvalent vaccine was obtained by mixing the monovalent vaccines . This polyvalent vaccine was tested by criteria usually applied to vaccine of E . coli strains with pathogenicity to man, and it exhibited the same quality characteristics.

Biophys Chem, 1979 Jan, 9(2), 121 - 31
Interaction of phenosafranine with nucleic acids and model polyphosphates . III . Heterogeneity in phenosafranine interactions with DNA base pairs; Balcarova Z et al.; Fluorescence and circular dichroism spectral measurements, thermal denaturation studies and binding competition experiments with netropsin and actinomycin D were carried out in systems containing phenosafranine bound to DNA's differing in base composition . The investigated properties exhibit a heterogeneity related to the content of A.T and G.C pairs in DNA and to the nature of phenosafranine binding modes . At low level of saturation of binding sites (r less than 0.1) phenosafranine does not show strong preference for any of the DNA base pairs in the overall binding . However, the strong monomer non-cooperative binding outside the helix (mode I1) occurs predominantly, even though not exclusively in G.C rich regions . The strong binding modes involving intercalated dye molecules (mode I2 and eventually mode II1) prevail in A.T rich regions . These binding modes become the principal types of strong phenosafranine interaction with DNA when the level of saturation of binding sites increases, i.e . at r greater than 0.1.20

J Bacteriol, 1979 Jan, 137(1), 340 - 9
Isolation and characterization of an endogenous inhibitor of protein synthesis in Escherichia coli K-12; Clark VL; A low-molecular-weight factor was isolated from cell extracts of Escherichia coli K-12 . The concentration of the factor in cells was dependent upon nutritional conditions, the concentration being higher in faster growing cells . Treatment of cells with colicin K caused an increase in concentration of the factor . The factor inhibited protein synthesis in E . coli . This inhibition was reversible, apparently because of metabolism of the factor . The inhibition of synthesis of beta-galactosidase lasted longer than the inhibition of protein synthesis; cyclic AMP eliminated this difference . The factor inhibited the synthesis of beta-galactosidase from preformed lac mRNA, indicating an inhibition of translation . Kinetic studies of the onset of inhibition of beta-galactosidase synthesis by the factor suggested that the factor may inhibit protein synthesis at the initiation of translation.

J Bacteriol, 1979 Jan, 137(1), 137 - 45
Tight-binding repressors of the lac operon: selection system and in vitro analysis; Pfahl M; The isolation and characterization of altered repressors of the lac operon which have an increased affinity for an operator should give useful clues about the molecular basis for the very tight and specific interaction between repressor and operator . A selection system has been devised which allows the isolation of such repressor mutants . This system selects for mutant repressors which can overcome lac operator-constitutive (Oc) mutations . By using in vivo assays, 24 candidates were obtained which, compared with wild type, have an increased trans effect of their repressor on one or several Oc operators . Three of these candidates have been investigated in vitro; the affinity of their repressor for inducer was unchanged, whereas the affinity for wild-type operator was increased 15-, 86-, and 262-fold, respectively.

Prikl Biokhim Mikrobiol, 1979 Jan-Feb, 15(1), 74 - 81
{Synthesis and study of biospecific sorbents for isolating and purifying L-asparaginase from Escherichia coli}; Vlasov GP et al.; Amino acid and oligoamide derivatives of D-asparagine and L-asparaginic acid (L-asparaginase inhibitors) have been synthesized . An increase in the hydrophobic capacity of the modified inhibitor increases the inhibition constant . Once the modified inhibitor binds with Sepharose 6B, the length of the spacer (a chain of atoms attaching the inhibitor to the polymer matrix) determines affinity of the sorbent for L-asparaginase . On these sorbents affinity shifts from pH optimum of the enzyme activity to pH 4-5 . The enzyme of E . coli L-asparaginase has been purified.

Mol Gen Genet, 1979, 172(3), 339 - 43
Repetitive DNA in Escherichia coli: multiple sequences complementary to small stable RNAs; Bailey SC et al.; Radioactively labeled 4.5S, 6S, and 10S RNAs from Escherichia coli were hybridized to EcoRI fragments from the E . coli genome . Each of these molecules bound to more than one DNA fragment . Cot curve analysis of the kinetics of the annealing of these RNAs to denatured E . coli DNA suggests that the DNA corresponding to each of these molecules is reiterated in the genome . These experiments also suggest that these reiterated sequences are non adjacent.

Acta Biol Med Ger, 1979, 38(11-12), 1549 - 53
An efficient procedure for serial nucleic acid hybridizations by titration analysis; Coutelle C et al.; A simplified and efficient procedure has been developed for performing hybridization reactions and analyses of the percentage of hybridization on glass plates . This method is as accurate as conventional methods, while considerably reducing the time and costs to perform the hybridization in titration hybridization experiments.

Mol Gen Genet, 1979, 177(1), 103 - 12
Isolation and characterisation of a strain carrying a conditional lethal mutation in the cou gene of Escherichia coli K12; Orr E et al.; A strain which carries a mutation conferring clorobiocin resistance and temperature sensitivity for growth was isolated from Escherichia coli K12 . Genetic mapping and the molecular weight of the gene product suggest that the mutation is in the cou gene, specifying a sub-unit of DNA gyrase . Nuclear organisation and segregation and placement of septa are grossly abnormal in the mutant at 42 degrees C . RNA synthesis and initiation of DNA replication are also affected at the restrictive temperature but the rate of DNA chain elongation continues almost undisturbed.

J Supramol Struct, 1979, 10(4), 443 - 55
The accessibility of antigenic determinants of ribosomal protein S4 in situ; Winkelmann D et al.; Antibodies to Escherichia coli ribosomal protein S4 react with S4 in subribosomal particles, eg, the complex of 16S RNA with S4, S7, S8, S15, S16, S17, and S19 and the RI reconstitution intermediate, but they do not react with intact 30S subunits . Antibodies were isolated by three different methods from antisera obtained during the immunization of eight rabbits . Some of these antibody preparations, which contained contaminant antibodies directed against other ribosomal proteins, reacted with subunits, but this reaction was not affected by removal of the anti-S4 antibody population . Other antibody preparations did not react with subunits . It is concluded that the antigenic determinants of S4 are accessible in some protein deficient subribosomal particles but not in intact 30S subunits.

Acta Microbiol Pol, 1979, 28(3), 213 - 20
New types of Escherichia coli K-12 facultative recombination deficient mutants resistant to ultraviolet; Baj J et al.; Numerous facultative temperature sensitive recombination deficient mutants of Escherichia coli K-12 strain 108 were isolated after mutagenization with nitrosoguanidine . The majority of the mutants were resistant to UV irradiation . Three mutants, KBP72, KBP169 and KBP610, with marked recombination deificiency (300 to 15,000 times) at 42 degrees C, were UV resistant; their sensitivity to mitomycin C was altered only slightly or not at all . Mutation KBP72 was co-transduced with ilv (83 unit on E . coli genetic map) . The mutant is not able to form a functional recombinat structure . Two other mutations are located between 0 and 19 unit of the genetic map.

Acta Microbiol Pol, 1979, 28(1), 53 - 62
Mutants of Escherichia coli with altered level of beta-N-acetylglucosaminidase activities; Hrebenda J; Five strains of Escherichia coli with reduced level of beta-N-acetylglucosaminidase activity were isolated . The mutations responsible for reduced activity of the enzyme have been localized in one of the strains between 25 and 27 minutes on the genetic map of E . coli . The mutants do not differ morphologically from the original strain . This suggest that beta-N-acetylglucosaminidase is of the secondary importance in the biosynthesis of murein.

Acta Microbiol Pol, 1979, 28(1), 5 - 14
Spermine hinders post-conjugational recombination in Escherichia coli K-12; Bialkowska-Hobrzanska H et al.; Treatment of Hfr and F- mixture with spermine during the first minutes of mating decreased the number of viable recombinants and inhibited functional recombinant structure formation in the intragenic cross lacz157Xlaczs . The treatment applied after 15 minutes of mating was ineffective . The decrease of recombination frequency was not caused by any interference in mating union formation . The efficiency of donor DNA transfer in the presence of spermine was increased two-fold . Spermine blocked the formation of S1-nuclease degradable DNA in the post-conjugant recipient cells . It is suggested that spermine probably interferes with the early steps of recombination, most likely by the stabilization of DNA against strand separation.

J Gen Microbiol, 1979 Jan, 110(1), 203 - 10
On the serological specificity of the Escherichia coli O8 and O9 antigens; Jann K et al.; The O8 and O9-specific lipopolysaccharides of Escherichia coli lost their serological activity during liberation of the polysaccharide moieties (alpha-mannans) by mild acid hydrolysis, as tested by passive haemagglutination and haemagglutination inhibition . The serological activities and specificities were restored by substitution of the polysaccharides with 1 to 2 stearoyl groups per polysaccharide chain . The mannans obtained by biosynthesis in vitro were serologically active only when bound to the membrane-associated hydrophobic carrier molecule . Liberation of the polysaccharides from the carrier by treatment with aqueous phenol resulted in loss of the serological activity . The O8- and O9-specific mannans of E . coli are thus serologically active when they are part of an amphiphilic molecule and not as free polysaccharides.

Proc Natl Acad Sci U S A, 1979 Jan, 76(1), 106 - 10
Expression in Escherichia coli of chemically synthesized genes for human insulin; Goeddel DV et al.; Synthetic genes for human insulin A and B chains were cloned separately in plasmid pBR322 . The cloned synthetic genes were then fused to an Escherichia coli beta-galactosidase gene to provide efficient transcription and translation and a stable precursor protein . The insulin peptides were cleaved from beta-galactosidase, detected by radioimmunoassay, and purified . Complete purification of the A chain and partial purification of the B chain were achieved . These products were mixed, reduced, and reoxidized . The presence of insulin was detected by radioimmunoassay.

J Periodontol, 1979 Jan, 50(1), 20 - 2
Histochemical study of strain L fibroblasts exposed to endotoxin . The effect on cellular organelles; Lucas RM et al.; Endotoxin was found to be nonselective in its cytotoxicity of cellular organelles . All organelles studied displayed some degree of alteration which became more severe as the concentration of endotoxin was increased . The data suggest that the metabolism of the cell may be compromised at concentrations of endotoxin which do not affect cell viability . The problem involved in attempting to determine the actual concentration of endotoxin at the interface between the culture medium and the cell monolayer, in vitro, and the corresponding situation, in vivo, are also discussed.

Mol Gen Genet, 1979, 172(3), 243 - 8
Lambda encodes an outer membrane protein: the lom gene; Reeve JN et al.; lambda infected minicells synthesize a polypeptide (M(r) = 20,500) which is incorporated almost exclusively into the outer membrane of the minicell envelope . The gene (lom = lambda outer membrane) encoding this polypeptide has been mapped in the non-essential region of the lambda genome between coordinates 39.4% and 40.7% of lambda.

Antonie Van Leeuwenhoek, 1979, 45(1), 13 - 8
On the role of the recipient cell during conjugation in Escherichia coli; Hoekstra WP et al.; To study the role of the E . coli recipient cell in conjugation recipient cell mutants deficient in conjugation (Con-) were isolated . Mutants specific for F-type E . coli donor cells (ConF-) and mutants specific deficient in conjugation with I-type donor cells (ConI-) were isolated . Both ConF- and ConI- mutants were blocked in stable mating pair formation . Biochemical analysis of the mutants suggests that the outer membrane protein coded by the ompA gene and LPS are important for recipient activity in F-type conjugation while LPS is important for recipient activity in I-type conjugation.

Biochimie, 1979, 61(11-12), 1257 - 72
The twenty aminoacyl-tRNA synthetases from Escherichia coli . General separation procedure, and comparison of the influence of pH and divalent cations on their catalytic activities; Kern D et al.; A general separation procedure of the twenty E . coli aminoacyl-tRNA synthetases including either a 105 000 g centrifugation or a poly-ethyleneglycol-dextran two-phases partition fractionation, and chromatographies on DEAE-cellulose, phosphocellulose and hydroxyapatite is described . The specific activities of the synthetases have been determined after each chromatographic step and compared to their respective activities in the 105 000 g supernatant . Some aminoacyl-tRNA synthetases were obtained at 80 per cent purity . The presence of phenylmethylsulfonyl fluoride does not significantly modify either the elution patterns of the synthetases during the various chromatographic steps or their specific activities . Thus, contrarily to enzymes from various eukaryotic organisms no significant inactivation of the E . coli aminoacyl-tRNA synthetases occurs via proteolytic processes during the purification procedure . The effects of various factors: pH, magnesium, and other bivalent cations including spermidine, were tested on the aminoacylation and the {32P} PPi-ATP isotope-exchange reactions, and the optimal aminoacylation and isotope-exchange conditions determined for 18 of the 20 E . coli aminoacyl-tRNA synthetases.

J Dial, 1979, 3(2-3), 191 - 205
Dialyzing room disinfection with ultra-violet irradiation; Inamoto H et al.; Infections represent a major problem in dialysis treatment, thus the dialyzing room should be kept abacterial as possible . We have installed 15-watt ultra-violet (U-V.) lamps for every 13.5 m2 on the ceiling for the purpose of the room disinfection and used them for 16 hours nightly after working hours . Bacteria were killed with over 10 hours irradiation even at the areas of low U-V . intensity where the irradiation may not be direct . This unexpected effectiveness might be from the influence of reflected rays and 03 produced . When half the lamps were turned on, the bacteriocidal effect was not sufficient in some areas . Any living organism with nucleic acids must be inactivated by this treatment, for the baceteriocidal effect is due to the nucleic acids injury . Furthermore, safety, readiness after the treatment, easy application and the negligible costs would make this method more advantageous to the other methods in room disinfection.

Circ Shock, 1979, 6(3), 245 - 53
The effect of methylprednisolone on hepatic oxygen supply and plasma lactate and glucose in endotoxemia; Casey JP et al.; This study was designed to determine the effect of methylprednisolone on the profile of hepatic oxygen supply and selected blood parameters in fasted, male rats administered an LD85 dosage of E coli endotoxin intraperitoneally . Mortality rates within 24 hours were 85% in rats receiving endotoxin only, 9% in rats receiving a 30 mg/kg dosage of methylprednisolone intraarterially one hour subsequent to endotoxin insult, and 0% in methylprednisolone controls . Beginning with the fourth hour, untreated endotoxin rats had significantly higher heart rates and lower plasma glucose; by the sixth or eighth hour there was significantly greater hypocapnia, lower blood pH, and higher plasma lactate levels in comparison to endotoxic rats receiving methylprednisolone . In addition, mean hepatic pO2 between the sixth and seventh hours was 2.6 mm Hg in endotoxic rats, 10.6 mm Hg in endotoxic methylprednisolone rats, and 17.7 mm Hg in methylprednisolone controls . Methylprednisolone controls showed a steady increase of plasma glucose levels through eight hours but were otherwise stable . Maintenance of hepatic circulation is cited as the probable basis for differences of morbidity and mortality between treated and glucocorticoid-treated endotoxic rats.

Scand J Gastroenterol, 1979, 14(3), 379 - 84
The prerequisites for local lysolecithin formation in the human gallbladder . III . Demonstration of two different phospholipase A activities; Tagesson C et al.; The positional specificity of the phospholipase A (EC 3.1.1.4) in human gallbladder epithelium has been studied using 14C-phosphatidylethanolamine radiolabeled either in the 1-acyl or in the 2-acyl position . After heating of homogenized epithelial cells at 70 degrees C for 2 min, their lysophospholipase activity was lost . In contrast, the ability to hydrolyze 14C-phosphatidylethanolamine in biosynthetically radiolabeled Escherichia coli was largely retained . The amounts of radioactivity found in the products of hydrolysis under different conditions suggest that there are two different phospholipase A activities in the gallbladder epithelium: one, with optimal activity at pH 7, that requires Ca2+ and is specific for the 2-acyl position, and another, with optimal activity at pH 4, that does not require Ca2+ and that, apart from the 2-acyl position, attacks the 1-acyl position as well . It is possible, therefore, that a complete deacylation of diacylphosphoglycerides in the gallbladder wall is brought about in two different ways: at neutral pH through a combined action of phospholipase A2 and lysophospholipase, the latter being able to hydrolyze the 1-acyl-lysophosphoglyceride, and, at acid pH, through the action of phospholipase A1 and A2 activity, presuming 1-acyl- and 2-acyl-lysophosphoglycerides are also attacked . Both these processes have to be considered in order to explain a turnover of diacylphosphoglycerides that physiologically would prevent the accumulation of lytic lysophosphoglycerides . The possible relevance of these findings to the pathogenesis of aseptic cholecystitis is inferred.

Can J Microbiol, 1979 Jan, 25(1), 116 - 8
Enumeration of stressed cells of Escherichia coli; Egan AF; Cells of Escherichia coli K-12 were stressed by heating at 48 degrees C or by acid treatment at pH 4.2 for periods up to 1h . The addition of catalase to the selective medium increased the count of heat-stressed cells by 2.3-fold and acid-stressed cells by 4.8-fold . However, these values represented only a small percentage (3% for heat-stressed and 6% for acid-stressed cells respectively) of the population of injured but still viable cells . The addition of mannitol to the selective medium used to count acid-stressed cells did not increase the count . Whilst the presence of H2O2 in media may cause significant errors in the estimation of E . coli in certain situations these errors are unlikely to be significant in physiological studies of populations of cells injured by stress.

N Engl J Med . 1978 Dec 28;299(26):1471.
Nutrient deficiencies in breast-fed infants; DNA sequence organization in the pea genome; The reassociation kinetics of pea (Pisum sativum L.) DNA fragments (300 nucleotides) were measured with hydroxylapatite . The most slowly reassociating fragments do so with a rate constant of 2 X 10(-4) L mol-1s-1, as determined from experiments with total DNA as well as with a tracer enriched for slowly renaturing sequences . This rate is about 1000 times slower than that observed for Escherichia coli DNA included as an internal kinetic standard, indicating a kinetic complexity of 4.5 X 10(9) nucleotide pairs or 4.6 pg of DNA per haploid nucleus . This estimate is in good agreement with previous chemical and cytophotometric measurements . The majority (85%) of the 300 nucleotide fragments contain repetitive sequences . While the reassociation of repetitive DNA could be modeled with two theoretical second-order components, the data did not specify a unique solution . The reassociation kinetics of isolated high- and low-frequency fractions indicate that repetitive sequence families in pea DNA probably cover a broad range of frequencies ranging from 100 to 10 000 or more copies per haploid genome . Single-copy sequences account for about 30% of the DNA, but because of extensive interpersion of repetitive sequences only about 15% of 300 nucleotide fragments reassociate with single-copy kinetics . From studies of hydroxylapatite binding as a function of fragment length, we conclude that the major class of single-copy sequences has a modal length of about 300 nucleotides . Long tracer reassociation kinetics indicate that sequences with an apparent repetition frequency of about 10 000 copies are interspersed at intervals of less than 1300 nucleotides throughout 75% of the genome . At a detection limit of about 3%, we find no single-copy sequences longer than 1000 nucleotides.

Biochemistry, 1978 Dec 26, 17(26), 5587 - 91
Kinetic mechanism of Escherichia coli carbamoyl-phosphate synthetase; Raushel FM et al.; The kinetic mechanism of Escherichia coli carbamoyl-phosphate synthetase has been determined at pH 7.5, 25 degrees C . With ammonia as the nitrogen source, the initial velocity and product inhibition patterns are consistent with the ordered addition of MgATP, HCO3-, and NH3 . Phosphate is then released and the second MgATP adds to the enzyme, which is followed by the ordered release of MgADP, carbamoyl phosphate, and MgADP . With glutamine as the ammonia donor, the patterns are consistent with a two-site mechanism in which glutamine binds randomly to the small molecular weight subunit producing glutamate and ammonia . Glutamate is released and the ammonia is transferred to the larger subunit . Carbamoyl-phosphate synthetase has also been shown to require a free divalent cation for full activity.

J Biol Chem, 1978 Dec 25, 253(24), 9049 - 52
Identification by affinity chromatography of the eukaryotic ribosomal proteins that bind to 5 S ribosomal ribonucleic acid; Ulbrich N et al.; Rat liver 5 S ribosomal RNA was oxidized with periodate and coupled by its 3' terminus to Sepharose 4B through an adipic acid dihydrazide spacer . The ribosomal proteins that bind to that nucleic acid were isolated by affinity chromatography and identified by electrophoresis in polyacrylamide gels . The eukaryotic 5 S rRNA binding proteins were L6 and L19: small amounts of L7, L23', L27/L27', L35', and L39 also were bound to the affinity column, but whether they associate directly and specifically with 5 S rRNA is not known . The proteins of the 40 S subunit of rat liver ribosomes did not bind to the 5 S rRNA affintiy column, nor did the proteins of either the large or small subparticle of Escherichia coli ribosomes.

J Biol Chem, 1978 Dec 25, 253(24), 8949 - 56
On the mechanism of rifampicin inhibition of RNA synthesis; McClure WR et al.; The mechanism of rifampicin inhibition of Escherichia coli RNA polymerase was studied with a newly developed steady state assay for RNA chain initiation and by analysis of the products formed with several 5'-terminal nucleotides . The major effect of rifampicin was found to be a total block of the translocation step that would ordinarily follow formation of the first phosphodiester bond . These effects were incorporated into a steric model for rifampicin inhibition . Additional minor effects of the enzyme bound inhibitor were to increase slightly the lifetime of RNA polymerase on the lambdaPR' promoter and to increase by two the apparent Michaelis constants of the initiating triphosphates . The products formed by RNA polymerase in the presence of rifampicin belong nearly exclusively to the class pppPupN . No evidence for the accumulation of such molecules was obtained in vivo.

J Biol Chem, 1978 Dec 25, 253(24), 8910 - 5
Purification and properties of cytochrome b556 in the respiratory chain of aerobically grown Escherichia coli K12; Kita K et al.; Cytochrome b556, a major component of type b cytochromes in the respiratory chain of aerobically grown Escherichia coli, was purified to near homogeneity . It was solubilized from cytoplasmic membranes by treatment with Sarkosyl/cholate mixture and purified by gel filtration on Sephadex G-200 . The purified cytochrome b556 is an oligomer composed of identical polypeptides, with a molecular weight of 17,500, determined by gel electrophoresis in the presence of sodium dodecyl sulfate . It contains equimolar amounts of heme and polypeptide but no detectable non-heme iron, phospholipid, or dehydrogenase . Its isoelectric point was determined to be 8.5 . The cytochrome b556 is highly hydrophobic in its amino acid composition and does not contain any half-cystine residues . The purified cytochrome b556 is spectrophotometrically pure and the alpha absorption peak in its difference spectrum at 77 K is at 556 nm . The molar extinction coefficient of cytochrome b556 was determined as 22.8 cm-1 mM-1 . Its oxidation-reduction potential was found to be -45 mV . It could be reduced by D-lactate dehydrogenase of E . coli in the presence of menadione.

J Biol Chem, 1978 Dec 25, 253(24), 8867 - 71
The primary structure of Escherichia coli K12 aspartokinase I-homoserine dehydrogenase I . Site of limited proteolytic cleavage by subtilisin; Briley PA et al.; The sequence of the first 25 residues of the homoserine dehydrogenase fragment, produced by limited proteolysis of aspartokinase I-homoserine dehydrogenase I with substilisin, has been determined . The sequence of a cyanogen bromide peptide (CB5, 59 residues), isolated from the entire protein, is also presented . Residues 1 to 18 of the subtilisin homoserine dehydrogenase fragment match the sequence 42 to 59 of peptide CB5.

J Biol Chem, 1978 Dec 25, 253(24), 8694 - 6
Allosteric activation of aspartate transcarbamylase with a fluorescent nucleotide analogue: linear-benzo-ATP; VanDerLijn P et al.; The interaction of Escherichia coli aspartate transcarbamylase with linear-benzo-ATP has been investigated by means of fluorescence spectroscopy . The fluorescent nucleotide analogue activates the enzyme to the same extent as ATP . Fluorescence polarization has been used to determine the association constant of lin-benzo-ATP with aspartate transcarbamylase (ATCase) which is 5 X 10(-3) M-1 at pH 8.7, at 4 degrees C, assuming six binding sites . This association constant is similar to those previously obtained for ATP at a variety of temperatures, buffers, and pH . The fluorescence emission of lin-benzo-ATP is not quenched when bound to ATCase, which indicates absence of pi interactions between the activator and tyrosyl residues in the protein . These residues have been implicated in the stereochemical mechanism of allosteric interactions in ATCase . Furthermore, this fluorescence behavior implicates hydrogen bond formation between the amino group of lin-benzo-ATP and a nucleophilic center at the enzyme binding site . The fact that lin-benzo-ATP activates ATCase is consistent with a previously published model for nucleotide regulation of the enzyme.

Science, 1978 Dec 22, 202(4374), 1290 - 3
Design of liposomes for enhanced local release of drugs by hyperthermia; Yatvin MB et al.; Liposomes can be designed to release an entrapped drug preferentially at temperatures attainable by mild local hyperthermia . In a test system in vitro, protein synthesis by Escherichia coli is inhibited and killing of the cells is enhanced by heating neomycin-containing liposomes to their phase transition temperature to maximize drug release . In the presence of serum the ratio of release at 44 degrees C to that at 37 degrees C can be made greater than 100:1, suggesting possible applications in the treatment of tumors or local infection.

Biochim Biophys Acta, 1978 Dec 21, 521(2), 689 - 707
Effect of estrogen on gene expression in the chick oviduct . In vitro transcription of the ovalbumin gene; Tsai MJ et al.; Problems involved in using the Hg-nucleotide technique for in vitro chromatin transcription are 2-fold . First, Escherichia coli RNA polymerase can utilize endogenous RNA as template and synthesize complementary sequences which remain base-paired to the template, thereby allowing it to bind to the SH-Sepharose column and copurify with the newly synthesized Hg-RNA . Second, non-mercurated endogenous RNA can bind to the SH-Sepharose through aggregation with Hg-RNA and thus be retained in the final RNA preparation . These two problems associated with the Hg-nucleotide technique can be minimized by modifying the conditions for RNA synthesis and SH-Sepharose chromatography . Using the modified procedure the Hg-nucleotide and SH-Sepharose technique can remove more than 90% of endogenous RNA contaminants . In order to directly demonstrate that the mRNAov sequences detected in vitro result from de novo transcription of oviduct chromatin, experiments were carried out which show that the hybridizable RNA sequences contain the Hg element and that the synthesis of these RNA sequences is sensitive to low concentrations of actinomycin D . These combined results strongly suggest that the majority of mRNAov sequences detected by hybridization to cDNAov is indeed due to DNA-dependent RNA synthesis by E . coli RNA polymerase and not due to an artifact of endogenous RNA contamination . This observation was further supported by data obtained using a filter hybridization method which measures directly the mRNAov sequences present in {3H}RNA synthesized from chromatin . The 3H-labeled ovalbumin messenger RNA was assayed by hybridization to cloned pOV230 DNA containing the ovalbumin structural gene sequence . With this modified Hg-nucleotide-SH-Sepharose technique and filter hybridization technique, we have restudied the in vitro transcription of the ovalbumin gene from chromatins isolated at different stages of hormone-induced oviduct development . The results are in agreement with our previous findings which suggest that the primary regulation of ovalbumin synthesis by steroid hormones occurs at the transcriptional level.

Biochim Biophys Acta, 1978 Dec 21, 521(2), 677 - 88
Modification of rat liver chromatin by N-methyl-N'-nitro-N-nitrosoguanidine or N-ethyl-N'-nitro-N-nitrosoguanidine and template activity for RNA synthesis by Escherichia coli RNA polymerase after reconstitution; Yoda K et al.; Rat liver chromatin was fractionated into DNA, histones and non-histone chromosomal proteins and each component was modified with N-methyl-l-N'-nitro-N-nitrosoguanidine of N-ethyl-N'-nitrosoguanidine . The radioactivity of 14C-labeled alkyl or guanidino moieties of both compounds bound significantly to both histones and non-histone chromosomal proteins and the binding of N-methyl-N'-nitro-N-nitrosoguanidine was higher than N-ethyl-N'-nitro-N-nitrosoguanidine . However the binding of both compounds to DNA was very low and its significance was hard to evaluate . All of the three components, one of which was modified, were reconstituted into chromatin, then, {3H}UMP incorporation into acid insoluble material using Escherichia coli RNA polymerase (EC 2.7.7.6) was measured . Only with the reconstituted chromatin containing histones modified either by N-methyl-N'-nitro-N-nitrosoguanidine or N-ethyl-N'-nitro-N-nitrosoguanidine, the template activity increased drastically; i.e., about 10 or 5 times higher than that with the unmodified reconstituted chromatin, respectively . However, any remarkable alteration in the electrophoretic pattern of protein fraction of the reconstituted chromatin could not be found . The results obtained in this study are discussed in the context that the modified histones could give rise to change in the mutual interaction of chromosomal components during the reconstitution of chromatin accompanied with the increase of chromatine template activity.

Biochim Biophys Acta, 1978 Dec 21, 521(2), 634 - 40
Guanine nucleotide metabolism in a mutant strain of Escherichia coli with a temperature sensitive lesion in rRNA synthesis; Harris JS et al.; We have described a mutant of Escherichia coli (designated 2S142) which shows specific inhibition of rRNA synthesis at 42 degrees C . ppGpp levels increase at the restrictive temperature, as expected . However, when the cells are returned to 30 degrees C, rRNA synthesis resumes before ppGpp levels have returned to normal . Furthermore, when ppGpp levels are decreased by the addition of tetracycline or choramphenicol, rRNA synthesis does not resume at 42 degrees C . Also, a derivative of 2S142 with a temperature-sensitive G factor (which cannot synthesize either protein or ppGpp at 42 degrees C) shows identical kinetics of rRNA shut-off at 42 degrees C as 2S142 . Thus, the elevated ppGpp levels in this mutant do not appear to be directly responsible for the cessation of rRNA synthesis at 42 degrees C.

Biochim Biophys Acta, 1978 Dec 21, 521(2), 619 - 33
Isolation and characterisation of 14-S RNA from spinach chloroplasts; Speirs J et al.; 14-S RNA was purified from spinach chloroplasts . It has a molecular weight of 0.43 . 10(6) and the following nucleotide composition: 20% CMP, 23.9% AMP, 24.2% GMP and 31.9% UMP . The accumulation of 14-S RNA in chloroplasts of cotyledons of dark-grown plants is stimulated by light . Conditions are described for the isolation of 14-S RNA in the absence of appreciable fragmentation of chloroplast 23-S rRNA and the evidence that it represents a distinct type of chloroplast RNA is discussed . Translation of 14-S RNA in a protein synthesising system from Escherichia coli gives rise to two polypeptides with molecular weights of 13 200 and 12 600 and the possible role of 14-S RNA as a chloroplast messenger is discussed.

Biochim Biophys Acta, 1978 Dec 21, 521(2), 529 - 46
Cross-linking and relaxation of supercoiled DNA by psoralen and light; Yoakum GH et al.; Photoreaction of 4,5',8-trimethylpsoralen with superhelical ColE1 and ColE1amp DNA was studied . Changes in mobilities in agarose gels, formation of interstrand cross-links, and DNA strand breaks were determined . Psoralen and light treatment removed negative superhelical turns, and extensive treatments failed to produce positive superhelical turns in covalently closed plasmid DNA . The rate of relaxation of superhelical turns by psoralen Photobinding appeared to be directly proportional to the number of superhelical turns remaining . A unique reaction mechanism is presented to explain these results . By this interpretation the initial rate of psoralen photobinding to superhelical DNA was estimated to be 3 times that for linear DNA, and the ratio of cross-linking to monofuctional adducts appears to be dependent on the superhelical conformation of the DNA . The estimated ratio of psoralen molecules bound to DNA strand breaks was 1.7 . 10(4):1, and 70% of this breakage is caused by the light alone.

Biochim Biophys Acta, 1978 Dec 18, 544(3), 676 - 9
Lipopolysaccharide interferes with the staining of lipoprotein on polyacrylamide gels; Loeb MR et al.; After electrophoresis of total membrane preparations of Escherichia coli B on sodium dodecyl sulfate polyacrylamide gels, and subsequent staining with Coomassie Brilliant blue, a band corresponding to the Braun lipoprotein fails to appear . This is in contrast to similar preparations of E . coli K-12 which do display the lipoprotein upon staining . Experiments described below indicate that failure to observe this protein in E . coli B is due to interference in the staining reaction by the lipopolysaccharide present in the membrane preparations.

Experientia, 1978 Dec 15, 34(12), 1578 - 9
Induction of deoxyribonucleic acid degradation in Escherichia coli by ozone; Hamelin C et al.; Cell survival and deoxyribonucleic acid (DNA) degradation wave measured for wild-type Escherichia coli B251 cells after exposure to different concentrations of ozone . The results show that extensive breakdown of DNA occurs after ozonation and that the extent of ozone-induced DNA degradation generally correlates with the colony-forming ability of the cells.

Klin Wochenschr, 1978 Dec 15, 56(24), 1217 - 24
{Immune defect syndrome in Crohn's disease (author's transl)}; Kleesiek K et al.; In 20 patients suffering for several years from serious chronic relapsing Crohn's disease the following immunological tests were carried out: (1) in-vitro stimulation of blood lymphocytes by PHA-P, (2) identification of T and B cells by formation of spontaneous rosettes and complement receptor rosettes, (3) effect of Crohn's serum on mixed lymphocyte reaction (MLR) of normal allogeneic lymphocytes, (4) in-vitro phagocytosis and intracellular killing of E . coli by polymorphonuclear granulocytes . The results indicate an immune defect of lymphocyte function and the effect of humoral factor(s) on T cell mediated immune reactions: (1) Lymphocyte stimulation by PHA-P was reduced significantly in Crohn's disease . In PHA-P dose response, maximal stimulation has shown a decrease and a shift to higher doses . (2) An increase in the absolute number of B cells caused a decrease in the mean percentage of T cells . The absolute number of T cells did not differ significantly from those of the controls . (3) Crohn's serum has shown an inhibitory effect in MLR of normal lymphocytes . (4) No impairment of phagocytosis or intracellular killing by polymorphonuclear granulocytes has been observed . The results suggest a symptomatic immune defect syndrome in a wasting disease . There is no evidence of a primary immune defect in Crohn's disease.

Nature, 1978 Dec 14, 276(5689), 689 - 94
The regulatory region of the biotin operon in Escherichia coli; Otsuka A et al.; It is proposed that the biotin anabolic operon in Escherichia coli is transcribed divergently from two partially overlapping face-to-face promoters . A mutation that increases transcription in vivo creates an additional promoter in vitro . The putative operator contains an imperfect palindromic sequence that partially overlaps the promoters . The regulatory and genetic implications of these findings are discussed.

Biochemistry, 1978 Dec 12, 17(25), 5489 - 93
Photoaffinity labeling of the ribosomal peptidyl transferase site with synthetic puromycin analogues; Vince R et al.; A photoaffinity labeling puromycin analogue, Nepsilon-(2-nitro-4-azidophenyl)-L-lysinyl puromycin aminonucleoside (NAP-Lys-Pan), was synthesized and used for investigation of the peptidyl transferase center of 70S riobsomes . Visible light irradiation of NAP-Lys-Pan led to covalent linkage of the analogue with Escherichia coli ribosomes . In a subsequent step, poly(uridylic acid) was employed to direct Ac{14C}Phe-tRNA to the P sites of the photolabeled ribosomes . Transpeptidation of Ac{14C}phenylalanine to the bound NAP-Lys-Pan resulted in selective incorporation of radioactive label into the peptidyl transferase A site . Dissociation of the ribosomes into subunits, and digestion of the RNA components, indicated that the radioactive label was incorporated into a protein fraction of the 50S subunit.

Biochemistry, 1978 Dec 12, 17(25), 5372 - 6
Phosphate content of Escherichia coli alkaline phosphatase isozymes . The effect of phosphate and zinc on the separation of isozymes; McManaman J et al.; Alkaline phosphatase from Escherichia coli was isolated as two major isoenzyme forms that were separated by DEAE-cellulose chromatography . Each form contained 2 equiv of endogenous phosphate . The endogenous phosphate, although difficult to remove, readily exchanges with phosphate . The forms also were separable by polyacrylamide gel electrophoresis . Apoenzyme prepared from native enzyme by the removal of zinc (and phosphate) also contains electrophoretically distinct enzyme forms which are indistinguishable from the native forms on gel electrophoresis . The isozymes were also found to have similar affinities for inorganic phosphate and susceptibilities to inactivation by EDTA . These results are not consistent with the notion that the formation or separation of isoenzyme forms is dependent upon different amounts of bound phosphate . They are consistent with the suggestion that a difference in amino acid composition is the basis for the occurrence and separation of these isoenzymes.

Biochemistry, 1978 Dec 12, 17(25), 5368 - 72
Characterization of the guanosine 5'-triphosphate 3'-diphosphate and guanosine 5'-diphosphate 3'-diphosphate degradation reaction catalyzed by a specific pyrophosphorylase from Escherichia coli; Heinemeyer EA et al.; Guanosine 5'-triphosphate 3'-diphosphate (pppGpp) and guanosine 5'-diphosphate 3'-diphosphate (ppGpp) are specifically degraded by a manganese-dependent pyrophosphorylase present in spoT+ but not in spoT- strains of Escherichia coli, indicating that the enzyme is the spoT gene product . The enzyme catalyzes the release of pyrophosphate from the 3' position of ppGpp or pppGpp, yielding ppG and pppG, respectively; pppGpp could not be detected as an intermediate in the decay reaction . Degradation of (p)ppGpp is optimal in the presence of 200 to 300 mM potassium or sodium acetate, at a pH of 7.5 to 8 and a temperature of 37 degrees C.

Biochemistry, 1978 Dec 12, 17(25), 5377 - 82
Acyl carrier protein from Escherichia coli: characterization by proton and fluorine-19 nuclear magnetic resonance and evidence for restricted mobility of the fatty acid chain in tetradecanoyl-acyl-carrier protein; Gally HU et al.; The acyl-carrier protein (ACP) of Escherichia coli is a protein of molecular weight 8847 with a 4'-phosphopanthetheine prosthetic group . ACP functions (via the SH of the prosthetic group) as a coenzyme in the synthesis of fatty acids and complex lipids . We report proton nuclear magnetic resonance (NMR) studies of the structure of ACP under various experimental conditions . The motion of the fatty acyl chain of acyl-ACP has been investigated by 19FNMR studies of difluorotetradecanoyl-ACP . 31PNMR studies of the prosthetic group phosphorus of ACP and acyl-ACP are also reported . We make the following conclusions: (1) the structure of ACP is stabilized by surface charge, and (2) the fatty acid residue of acyl-ACP does not move freely and seems immobilized by an interaction with the protein moiety.

J Biol Chem, 1978 Dec 10, 253(23), 8493 - 8
Differential scanning calorimetry of asparate transcarbamoylase and its isolate subunits; Vickers LP et al.; The thermal denaturation of aspartate transcarbamoylas of Escherichia coli was investigated by differential scanning calorimetry . Isolated regulatory and catalytic subunits were heat denatured at 55 and 80 degrees C, respectively . In contrast, the intact enzyme was denatured in two steps . A small endotherm near 73 degrees C was assoicated with denaturation of the regulatory subunits and the major endotherm at 82 degrees C with denaturation of the catalytic subunits . Thus regulatory subunits are stabilized against heat denaturation by more than 17 degrees C when incorporated in the enzyme . Similar conclusions were obtained from measurements of the enthalpy of heat denaturation . Regulatory subunits yielded a much lower value of the enthalpy of denaturation, 1.91 cal/g, than that found for the catalytic subunit, 3.94 cal/g, or typical globular proteins (4 to 6 cal/g) . When the regulatory subunits were incorporated into aspartate transcarbamoylase their enthalpy of denaturation was increased 125% (to 4.3 cal/g) . The enthalpy of the catalytic subunits in the intact enzyme was increased 38% (enthalpy of denaturation of 5.43 cal/g) . Stabilization of the isolated catalytic subunit as well as the intact enzyme was achieved by the addition of the bisubstrate analog N-(phosphonacetyl)-L-aspartate . Similarly the allosteric effectors, CTP and ATP, stabilized the isolated regulatory subunits or those subunits within the intact enzyme . However, the addition of the bisubstrate analog caused a decrease in the enthalpy of denaturation of the regulatory subunits within the enzyme . These results are consistent with other studies of the ligand-promoted conformational changes in the native enzyme.

J Biol Chem, 1978 Dec 10, 253(23), 8351 - 4
The peptide chain elongation factor genes tufA and fus of Escherichia coli are intimately related physically; Furano AV et al.; Recent work from several laboratories has established the following points about the synthesis of the polypeptide chain elongation factors Tu and G in Escherichia coli . (i) Elongation factor Tu is the product of duplicate, highly conserved genes, tufA and tufB, which are widely separate parts of the chromosome . (ii) The molar concentration of this factor is considerably higher than that of elongation factor G which is encoded by the fus gene . (iii) Although the tufA and fus genes are close together and can be co-transcribed in the direction from fus to tufA, the tufA gene product is synthesized at several times the rate of the fus gene product . In an attempt to understand what mechanism(s) could account for the differential expression of the tufA and fus genes, we sought to obtain more precise information on the physical relationship of these genes . By examining heteroduplexes between restriction endonuclease-generated fragments of DNA containing the tufA, fus, and tufB genes, we have demonstrated that the fus and tufA genes are intimately related physically in one of two possible arrangements . Either the NH2-terminal region of the tufA gene is contiguous with the COOH-terminal region of the fus gene or the beginning of the tufA gene overlaps part of the fus gene . These results mean that if the tufA gene is always co-transcribed with the fus gene, then some mechanism must allow the tufA portion of the transcript to be translated more often than the fus gene portion of the transcript.

Biochim Biophys Acta, 1978 Dec 8, 527(2), 414 - 24
Phospho-N-acetylmuramoyl-pentapeptide-transferase of Escherichia coli K12 . Properties of the membrane-bound and the extracted and partially purified enzyme; Geis A et al.; Phospho-N-acetylmuramoyl-pentapeptide-transferase (UDP-N-acetyl-muramoyl-L-alanyl-D-gamma-glutamyl-L-lysyl-D-alanyl-D-alanine:undecaprenoid-alcohol-phosphate-phospho-N-acetylmuramoyl-pentapeptide-transferase, EC 2.7.8.13) was solubilized by repeated freezing and thawing of crude envelopes of Escherichia coli K12 . The solubilized enzyme was partially purified by gel filtration and ion-exchange chromatography . This preparation contained small amounts of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol but no endogenous lipid substrate, C55-isoprenyl phosphate, could be detected . Some catalytic properties (exchange reaction) of the solubilized enzyme were compared to those of membrane-bound transferase . The transfer activity of the partially purified transferase was restored by the addition of an aqueous lipid dispersion . All the transferase activity was found to become incorporated into the liposomes . Preincubation of the transferase preparation with phospholipase A2 or D strongly reduce both exchange and transfer activity . This suggests that phospholipids sensitive to phospholipases are necessary for the enzymatic reaction . Different effects of some neutral detergents on the exchange activity were reported.

Biochim Biophys Acta, 1978 Dec 4, 514(1), 117 - 27
Release of a special fraction of the outer membrane from both growing and phage T4-infected Escherichia coli B; Loeb MR et al.; Growing Escherichia coli release envelope material into the medium . Upon infection with T4 phage increased amounts of this material are released and at a greater rate . In order to determine whether both inner and outer membranes are present in this material, and whether the material released by growing cells differs from that released by infected cells, we have examined the protein composition of envelope released by growing and T4-infected E . coli B . Our results show: (a) the protein composition of envelope released from growing or infected cells is similar, (b) the proteins present are representative of the outer membrane, (c) the major outer membrane protein of E . coli B, protein II, is deficient in the released material . We therefore conclude that the envelope material released from growing or infected E . coli represents a special fraction of the outer membrane . This finding is discussed in relation to outer membrane structure and function . In addition, data are presented on the differing outer membrane protein composition of substrains of E . coli B obtained from different laboratories.

Biochim Biophys Acta, 1978 Dec 4, 514(1), 128 - 36
Isolation of the membranes of an enterotoxigenic strain of Escherichia coli and distribution of enterotoxin activity in different subcellular fractions; Wensink J et al.; The intracellular localization of enterotoxin in Escherichia coli AP1, a strain of porcine origin which produces high levels of heat-labile, but no heat-stable enterotoxin, has been examined . The cytoplasmic and outer membranes of this strain both contained enterotoxin activity, while the membranes isolated from a serologically related non-enterotoxigenic strain (E . coli AP2) also of porcine origin, did not show enterotoxin activity . The periplasmic fraction isolated from the enterotoxigenic strain contained considerable enterotoxin activity, but this activity was associated with outer membrane fragments present in the periplasmic fraction . Thus, of the total cellular enterotoxin activity, about 55%, 15% and 30% were present in the outer membrane, cytoplasmic membrane and the cell cytoplasm, respectively . The specific activity of enterotoxin was 20 units per mg protein in the cytoplasm and 90 and 150 units per mg protein in the cytoplasmic and outer membranes, respectively.

J Cell Sci, 1978 Dec, 34, 233 - 46
DNA-binding properties of nuclear matrix proteins; Comings DE et al.; Mouse nuclear matrix proteins, examined by a filter assay, were found to bind to DNA . There was no preference for homologous mouse compared to heterologous E . coli DNA . Competition assays showed a preference for AT-rich DNA and of the 4 single-stranded homopolymers there was a preference for poly(dT) . These observations are consistent with the possibility that the matrix may play a role in the formation of AT-rich chromomeres (G-bands).

Cell, 1978 Dec, 15(4), 1199 - 208
Trans-complementation-dependent replication of a low molecular weight origin fragment from plasmid R6K; Kolter R et al.; A non-self-replicating segment (1370 base pairs) of plasmid R6K was cloned in E . coli and shown to trans-complement temperature-sensitive replication mutants of this plasmid . This segment contains the gene which codes for a protein required for initiation of replication of the plasmid, and was used as a helper in a functional assay for an origin of replication in R6K derivatives . A 420 bp fragment, derived from R6K DNA, was shown to carry a functional origin since it was capable of replicating as a plasmid in E . coli cells carrying the helper segment either on the host chromosome or on a plasmid Col E1 derivative . The copy number of the origin fragment in cells carrying the helper segment on the chromosome is essentially the same as the copy number of R6K . A model for the positive regulation of plasmid R6K replication is presented.

Natl Cancer Inst Monogr, 1978 Dec, (50), 121 - 7
Mutagenesis and cell transformation by ultraviolet irradiation: many hypotheses for few results; Radman M et al.; UV light-induced mutagenesis in bacteria is a genetically controlled process dependent on induction of some cellular functions, provoked initially by unrepaired photolesions in the DNA . Experiments on the extent and fidelity of in vitro DNA systhesis on UV-irradiated templates by bacterial mammalian DNA polymerases suggest a crucial role for 3' to 5' exonuclease (proofreading) activity in UV light-induced mutagenesis . Two-stage carcinogenesis (initiation and promotion) is discussed in terms of two-stage mutagenesis (mutation fixation in the DNA and mutation expression) . A unifying concept for both mutational and viral malignant transformation is proposed.

Natl Cancer Inst Monogr, 1978 Dec, (50), 115 - 9
Analysis of base substitutions induced by ultraviolet radiation in Escherichia coli; Coulondre C et al.; A system for determining the precise specificity of mutagens operating on Escherichia coli has been described, and the results for UV irradiation have been presented . Attempts to correlate the base pairs preferentially mutated by UV light with pyrimidine-pyrimidine sequences are discussed.

Biometrics, 1978 Dec, 34(4), 593 - 602
Measures of association between disease and genotype; Norwood PK et al.; This paper is concerned with the statistical aspects of the phenomenon of disease occurring more frequently in individuals with some genotypes than in individuals with others . A correlation coefficient is defined to quantify association between disease and genotype . A distinction is made between the concepts of independence of allele and disease and independence of genotype and disease . This distinction is used to define two components of association which describe separate aspects of association of disease with genotype . One component is a measure of the association of disease with allele; the other a measure of the effect of allele interaction on association of disease and genotype . One aspect of the usefulness of the partition into components which is discussed is in expressing the recurrence risk of disease for a relative of an affected individual . A chi-squared analysis is provided to test hypotheses about the components of association and other hypotheses of genetic interest . This analysis is illustrated using a study done to determine the effect of the sex-linked dwarfing gene in male chickens on resistance to E . coli infection . This analysis shows a significant allele interaction effect on resistance to disease but no association of disease with alleles . In conclusion, some extensions and limitations of the proposed concepts and procedures are discussed.

Toxicology, 1978 Dec, 11(4), 353 - 9
Alveolar macrophage function in nickel dust exposed rabbits; Jarstrand C et al.; 8 rabbits were exposed to metallic nickel dust (2 mg/m3, of which about half was respirable) for 4 weeks . The lungs were lavaged and the macrophages were collected . In comparison with 8 control rabbits, a significant increase was noted in the nickel exposed rabbits as concerned the weight and density of the lungs, the size variation of the lung cells, the phagocytosis of silver coated particles, and the metabolic activity as measured by NBT reduction . The last mentioned increase was recorded during basal conditions as well as during phagocytosis . The NBT reduction during phagocytosis was significantly correlated with the degree of phagocytosis of silver coated particles in both control and exposed rabbits . It is suggested that the exposure to nickel dust has unspecifically activated the macrophages perhaps by increased production of phospholipids.

Z Immunitatsforsch Immunobiol, 1978 Dec, 155(2), 93 - 103
Human fetal cells . I . Mitogenic responses; Faust J et al.; Human fetal cells from 10 prematures and newborn infants (28--38 weeks of gestational age) and isolated or non-isolated fetal cells circulating in the blood of 9 primigravidae were studied in their ability to respond to phytohemagglutinin, pokeweed, dextran sulfate and lipopolysaccharide . An age-dependent responsiveness of fetal cells obtained from the prematures to all mitogens tested was detected as well as a clear graduation of mitogenic capacity with phytohemagglutinin to produce the highest stimulation . Though a moderate mitogenic response to lipopolysaccharide and dextran sulfate was noted in the blood cultures of the infants, LPS and in part DS transformation of fetal cells obtained from maternal blood appeared to be reduced or absent . A selective stimulation of fetal cells occurring in the circulation of primiparae sufficient for prenatal diagnosis could not be achieved with the mitogens tested . The findings suggest that fetal cells crossing to the mother are different from normal fetal lymphocytes . The present study was performed to elucidate in as quantitative a manner as possible the responses of human fetal cells to different T- and B-cell mitogens . Cells were obtained from various sources for comparing the mitogenic responses of isolated and non-isolated fetal cells . Our results demonstrate that mitogenic responses depend on the gestational age of the fetal cells, the source of the cells and on experimental conditions.

Nucleic Acids Res, 1978 Dec, 5(12), 4919 - 31
Antibodies elicited by defined oligodeoxyribonucleotide sequences; Storl HJ et al.; Antibodies to the oligodeoxyribonucleotides d(pT)3, d(pT)4, d(pT)6 and d(pA-A-T-T) were elicited in rabbits by immunization with electrostatic complexes of the respective haptens with methylated bovine serum albumin (MBSA) . The antisera were assayed by complement fixation using denatured DNA's of various sources as antigens . The specificities of the antibodies were determined by estimating the inhibition of the complement fixation reaction by defined oligodeoxyribonucleotides . The antibodies were shown to be specific for the sequence of the oligode-oxyribonucleotides or parts of it.

Nucleic Acids Res, 1978 Dec, 5(12), 4753 - 9
2'-Deoxy-2'-fluorouridine-5'-phosphate: an alternative substrate for thymidylate synthetase from Escherichia coli K12; Wohlrab F et al.; The substrate specificity of 2'-deoxy-2'-substituted uridines and their 5'-phosphates towards thymidylate synthetase from Escherichia coli K12 was investigated . Besides the natural substrate 2'-deoxyuridine-5'-phosphate (dUMP), only 2'-deoxy-2'-fluorouridine-5'-phosphate (dUflMP) was a substrate . The KM of dUflMP is 11 times higher than that of dUMP, while the Vmax values are virtually the same . It is concluded that the size of the 2'-substituent and not its polarity (and the concomitant conformational change) determines substrate specificity of thymidylate synthetase.

Nucleic Acids Res, 1978 Dec, 5(12), 4593 - 611
Cloning of nematode tRNA genes and their expression in the frog oocyte; Cortese R et al.; Transfer RNA genes of the nematode Caenorhabditis elegans have been cloned in E . coli using the plasmid Col E1 as vector . The tRNAs coded by 3 hybrid plasmids were purified by hybridisation of labelled nematode tRNA with the plasmid DNAs . Each plasmid appears to code for a single distinct tRNA species . The expression of the cloned DNAs was analysed in vivo by injection into nuclei of Xenopus laevis oocytes . Evidence is presented which suggests that these nematode tRNA genes are accurately transcribed and processed in frog oocytes . Analysis of one hybrid plasmid shows that a 300 base pair DNA fragment contains both the structural gene and those regions required for its transcription in vivo . The results show that cloned eukaryotic DNAs from a heterologous source can be tested for functional gene activity in X . laevis oocytes.

Nucleic Acids Res, 1978 Dec, 5(12), 4547 - 62
The ovalbumin split gene: molecular cloning of Eco RI fragments "c" and "d"; LePennec JP et al.; The Eco RI fragments "c" and "d" of the ovalbumin gene (1, 2) have been isolated by molecular cloning . Restriction enzyme mapping and electron microscopy have confirmed that the two fragments contain the same ovalbumin mRNA coding sequences . These sequences are split into two regions which have been mapped in fragments "c" and "d" . There is no evidence that the ovalbumin mRNA sequences contained in these fragments could be further interrupted . Our results confirm that the presence of Eco RI fragment "d" in some chickens is due to the existence of an allelic variant of the ovalbumin gene which contains an additional Eco RI site within the region corresponding to Eco RI fragment "c" . This additional Eco RI site appears to be the main difference between the two alleles . Finally, our results provide a direct demonstration that most of the ovalbumin mRNA sequences are encoded for by Eco RI fragments "a", "b" and "c".

J Dairy Sci, 1978 Dec, 61(12), 1704 - 8
Survival of Escherichia coli, strain W, during the manufacture of cottage cheese; Vecchionacce RA et al.; Cottage cheese was manufactured in 10-liter experimental vats by the direct-acid-set method from milk that was inoculated with a heat resistant strain of Escherichia coli . Growth or survival of Strain W (ATCC 9637) E . coli was determined at various stages of the cheese making operation after the cheese-skim milk was inoculated to give counts of 2.5 X 10(4) or 4.0 X 10(5) cells/ml . Numbers of coliform organisms remained constant at the inoculated concentration in the cheese milk up to a cooking temperature of 43 C . At 43 C, when curd was separated from the whey, the curd (not washed) had coliform counts that were two log cycles greater than the whey . These trends were in milks with both cell counts . Washing of the curd with acid and 10 ppm chlorine reduced the number of coliform cells in the curd at all cooking temperatures as compared with unwashed curd . Acid wash of the curd at pH 5 did not reduce the coliform counts below those of unwashed curd . Cooking temperatures of 54 C were necessary to destroy (less than 1 cell/ml) E . coli Strain W, in either the unwashed or acid-chlorine washed curd . Holding curd with an initial average log count of 6.26 coliform cells/ml at constant temperatures of 38, 43, 49, and 54 C confirmed that 54 C for 50 min was necessary to reduce the average count to less than 1 cell/ml in isolated curd . Coliforms in whey were reduced to that concentration after 10 min at 54 C.

J Clin Microbiol, 1978 Dec, 8(6), 700 - 3
Increased Escherichia coli enterotoxin detection after concentrating culture supernatants: possible new enterotoxin detectable in dogs but not in infant mice; Nalin DR et al.; The heat-stable enterotoxin (ST) of Escherichia coli can be detected by infant mouse or dog intestinal loop tests . These tests differ in that the dog assay uses concentrated culture supernatants and is based on measurements of net intestinal absorption, whereas the mouse test uses unconcentrated supernatants and depends on gross fluid accumulation . To compare the relative sensitivities of these assays, culture supernatants of randomly selected E . coli isolates from 34 Bangalee diarrhea patients were tested for ST in dog loops and infant mice . Supernatants were also tested for heat-labile enterotoxin (LT) in dog loops, Y-1 adrenal cells, and Chinese hamster ovary cells . E . coli supernatants that produced positive responses for both ST and LT in the dog loop assay (ST+/LT+) also produced positive responses when tested for ST in infant mice and for LT in cell lines . Supernatants of strains negative for ST and LT in dog loop (ST-/LT) were also negative in other assays . Of 10 strains positive for just ST in the dog loop test (ST+/LT-), only 5 were ST positive in the standard infant mouse test . Supernatants of the other five strains (dog loop positive, mouse test negative) were then concentrated 100-fold and retested in mice . Three of these five gave consistently positive results after concentration, and two were only intermittently positive . Concentrated supernatants of negative control strains (ST-/LT-) were all negative in mice . The dog assay detects more strains producing ST than the infant mouse test . The infant mouse test, which detects only gross fluid accumulation, failed to detect approximately half of the 10 strains which produced ST alone (ST+/LT-; P = 0.025) . Concentrating supernatants for the mouse assay increases sensitivity for detection of ST, but certain E . coli strains produce a variety of ST to which infant mice do not respond.

Gene, 1978 Dec, 4(4), 295 - 308
Cloning of the phr gene and amplification of photolyase in Escherichia coli; Sancar A et al.; A new technique is developed for physically enriching recombinant DNA molecules in an in vitro recombination mixture . UV-irradiation of the donor DNA before recombination enables photoreactivating enzyme (PRE) (deoxyribodipyrimidine photolyase, EC 4.1.99.3) to attach to the donor segments in recombinant molecules . This attached protein causes retention of the recombinant molecules on a nitrocellulose filter, while molecules not containing donor DNA pass through . The bound DNA is repaired of its UV damage and released for insertion into cells by exposure to photoreactivating light in situ, yielding approx . 350-fold enrichment . Although applicable to any gene, this procedure has been used in cloning the Escherichia coli phr gene itself, permitting 100-fold amplification of the gene product in vivo.

Genetics, 1978 Dec, 90(4), 659 - 71
Isolation, genetic mapping and some characterization of a mutation in Escherichia coli that affects the processing of ribonuleic acid; Apirion D; Temperature-sensitive mutants were isolated from an rnc (RNase III-) strain of Escherichia coli, and their rRNA metabolism was analyzed on 3% polyacrylamide gels . One of these mutants was unable to produce 23S and 5S rRNAs at the nonpermissive temperature . When an rnc+ allele was introduced to this strain, it remained temperature sensitive . At the nonpermissive temperature, this strain could then produce 23S rRNA but was unable to make normal levels of 5S rRNA . In matings and transduction experiments, the defect in rRNA metabolism and temperature sensitivity behaved as a syndrome caused by a single point mutation, which was mapped at min 23.5 on the E . coli chromosome . This mutation probably affects an enzyme, ribonuclease E (RNase E), which introduces a cut in the nascent rRNA transcript between the 23S and the 5S rRNA cistrons . The mutation rne is recessive with respect to temperature sensitivity and the pattern of rRNA . Revertants able to grow at 43 degrees and with normal metabolism of rRNA were isolated; genetic analysis showed that they do not contain the original rne mutation, suggesting that they were true revertants . By combining the rne mutation with an rnc mutation, double rnc rne strains were synthesized, which behaved very similarly to the original rnc strain from which the rne mutation was isolated . Such strains have RNA metabolism that is similar to that of rnc strains at permissive temperatures, but at the nonpermissive temperature they fail to synthesize p23, m23, and 5S rRNAs . Thus, the experiments reported here, together with previous studies, suggest the existence of a new processing ribonuclease activity in Escherichia coli, which is called ribonuclease E.

Am Rev Respir Dis, 1978 Dec, 118(6), 1097 - 9
Pulmonary vascular effects of endotoxin in leukopenic dogs; Mlczoch J et al.; We have demonstrated previously that in the dog, small doses of endotoxin abolish the pulmonary vasoconstrictor reponse to hypoxia, apparently by stimulating the production of a vasodilator prostaglandin . We previously ruled out platelets as mediators of this endotoxin effect . To evaluate leukocytes as possible mediators, we rendered dogs leukopenic by means of a leukocyte antiserum . However, this did not modify the inhibitory effect of endotoxin on hypoxic pulmonary vasoconstriction . Hence, neither leukocytes nor platelets appear to mediate the endotoxin effect . In the near absence of both platelets and leukocytes, the endotoxin effect can be prevented by inhibiting prostaglandin synthesis with meclofenamate . This suggests that endotoxin prevents hypoxic pulmonary vasoconstriction by acting on the systemic circulation or on the lung (possibly directly on the pulmonary blood vessels) to stimulate the production of a vasodilator prostaglandin.

Mutat Res, 1978 Dec, 54(3), 283 - 8
Differential mutagenicity of N-methyl-N-nitrosocarbamate insectides in Escherichia coli strains having different DNA repair capacities; Yoshikawa K et al.; Four isogenic strains of Escherichia coli with the same auxotrophic marker (arg Fam--namely wild-type, uvrA-, polA- and recA-) were used for testing the lethalities and mutagenicities of 1-naphthyl N-methyl-N-nitrosocarbamate (nitroso-NAC), 3-methylphenyl N-methyl-N-nitrosocarbamate (nitroso-MTMC), and 3,4-dimethylphenyl N-methyl-N-nitrosocarbamate (nitroso-MPMC) . The strains recA- and polA- showed a similarly higher sensitivity to killing than wild-type and uvrA- after treatments with each of the three chemicals, whereas the strains wild-type, uvrA-, and polA- were equally mutable by these compounds at equal doses . The strain recA- was hardly mutable by nitroso-NAC, but significant levels of Arg+ mutations were observed after treatments with nitroso-MTMC and nitroso-MPMC . These and previous results suggest that both nitroso-MTMC and nitroso-MPMC are similar in their mutagenicity pattern to N-methyl-N'-nitro-N-nitrosoguanidine whereas nitroso-NAC is similar to methyl methanesulfonate or X-rays, and that the major damage to DNA of the three agents is not excisable by the uvrA+-dependent excision repair, probably methylation in DNA.

Mutat Res, 1978 Dec, 54(3), 265 - 70
Deuterium isotope effects in mutagenesis by nitroso compounds; Elespuru RK; Nitrosamines which have deuterium instead of hydrogen in the position alpha to the nitroso group have been reported to have reduced activity in carcinogenicity tests . This result implies that cleavage of a carbon--hydrogen bond is a limiting step in the reaction mechanism leading to tumor formation . Mutagenicity tests were undertaken with nitrosamines, which require metabolic activation, and with nitrosamides, which are directly acting mutagens, to determine the effect of deuterium substitution on the activity of each type of compound . Two nitrosamides (N-methyl-N'-nitro-N-nitrosoguanidine and methylnitrosourea) and three nitrosamines (dimethylnitrosamine, nitrosomorpholine, and dinitrosopiperazine) and their deuterium-containing analogs were tested for reversion of a nonsense mutation in the tyr locus of Escherichia coli WU 3610 (tyr-, leu-) . Nitrosamines activated by rat-liver microsomes, but not nitrosamides, were less active as mutagens when the deuterium atom was present . The results suggest that the metabolic activation of nitrosamines to a mutagenic species involves the loss of hydrogen, a reaction which the nitrosamides, in the absence of enzyme, do not undergo.

J Infect Dis, 1978 Dec, 138(6), 760 - 7
The pyrogenicity of the synthetic adjuvant muramyl dipeptide and two structural analogues; Dinarello CA et al.; The pyrogenic efect of the synthetic adjuvant N-acetylmuramyl-L-alanine-D-isoglutamine, also known as muramyl dipeptide (MDP), was studied in rabbits . MDP induced biphasic fevers in rabbits, but two structural analogues, N-acetylmuramyl-L-alanine-D-glutamic acid (MDPA) and the dimethylester of MDPA, were 10 times less pyrogenic . This finding was supported by studies in which MDP and its analogues released leukocytic pyrogen (LP) from rabbit phagocytic cells in vitro . In addition, MDP released LP from human phagocytes . Human phagocytes, however, required a 10-fold greater concentration of MDP than did rabbit cells . The structural analogues were similarly less effective than the parent molecule in releasing LP from human cells . All preparations of MDP were negative in the limulus amebocyte lysate test and failed to show pyrogenic cross-tolerance with bacterial endotoxin . Thus MDP, which is a pyrogenic molecule, is also able to release LP from rabbit phagocytes and to a lesser degree from human phagocytes, but does not cause gelation of limulus amebocyte lysate.

J Biochem (Tokyo), 1978 Dec, 84(6), 1637 - 40
Colicin E3 is an endonuclease; Ohno S et al.; It was confirmed by polyacrylamide gel electrophoresis that isolated 16S rRNA was cleaved by the active component (protein A) or the active fragment (T2A) of colicin E3 . However, the degradation was random, in contrast with the specific cleavage observed in the interaction of colicin E3 with ribosomes . Furthermore, the active component and the active fragment had low activities, and far greater amounts of these materials were required for degradation of the isolated rRNA than for ribosome inactivation . The degradation of rRNA cannot be due to contaminating ribonuclease(s), but is due to colicin E3 itself, because of the following facts . (1) Protein B of colicin E3, which specifically inhibits the ribosome-inactivating activity of colicin E3, inhibited the degradation of rRNA . (2) Protein B of colicin E2, which inhibits the action of colicin E2 but not of colicin E3, failed to inhibit the degradation of rRNA . (3) The activity appeared in the peak of protein A or fragment T2A, respectively, when they were rechromatographed on Sephadex G-75.

J Biochem (Tokyo), 1978 Dec, 84(6), 1389 - 99
In vitro synthesis of ornithine transcarbamylase; Dohi M et al.; An in vitro system for the synthesis of ornithine transcarbamylase (OTCase) was established using iS-30 extract from E . coli MDS6-2(lambda) and DNA of a lambda transducing phage carrying argI and argF genes . This in vitro synthesis was completely dependent on the additon of DNA, and was sensitive to chloramphenicol and rifampicin . Radioisotopic analysis confirmed that the synthesized enzyme catalyzes the carbamylation of ornithine to citrulline . In the in vitro system the repression and derepression of OTCase synthesis could be observed by mixing iS-30 extracts prepared from argR+ and argR- cells . A remarkable maturation effect could be observed for the FFF enzyme, but not for the III enzyme . This system is considered to reflect the in vivo situation, and should therefore be useful for investigations on the regulation of OTCase synthesis in vivo.

Eur J Biochem, 1978 Dec, 92(2), 491 - 8
Mutants (ompA) affecting a major outer membrane protein of Escherichia coli K12; Henning U et al.; Seventy independent mutants have been analyzed affecting a major protein, polypeptide II, of the outer cell envelope membrane from Escherichia coli K12 . They were classified as nonsense mutants of the amber type (20%), mutants most likely of the missense type possessing the protein at normal concentrations (9%), and mutants either missing the protein or harboring it at much reduced concentrations for unknown reasons (71%) . Forty of the mutants were analyzed genetically and all were found to map at or near ompA, the structural gene for protein II . Two-dimensional electrophoretic analyses of envelopes from such mutants revealed an unusual heterogeneity of the protein which on such patterns appeared as at least 12 well separated spots, and the majority of these is due to artifacts of the method but apparently specific for this protein . In no case was a polypeptide fragment found in envelopes from the nonsense mutants . The results are discussed regarding two different phages which use the protein as a receptor and concerning the biosynthetic incorporation of the protein into the outer membrane.

Eur J Biochem, 1978 Dec, 92(2), 411 - 5
Processing in vitro of precursor periplasmic proteins from Escherichia coli; Randall LL et al.; Precursors of two secreted periplasmic proteins in Escherichia coli, arabinose-binding protein and maltose-binding protein, were synthesized in vitro on membrane-bound polysomes . Addition of Triton X-100 to the system resulted in processing of the precursors to mature forms.

Biophys J, 1978 Dec, 24(3), 657 - 64
Strand breaks and alkali-labile bonds induced by ultraviolet light in DNA with 5-bromouracil in vivo; Krasin F et al.; Supercircular gamma phage DNA with 10 bromouracils/100 thymine bases, irradiated with 313 nm light in Tris buffer and sedimented on alkaline and neutral gradients, showed 4.6 alkali-labile bonds per true single-strand break, in agreement with Hewitt and Marburger (1975 Photochem . Photobiol . 21:413) . The same DNA irradiated in Escherichia coli host cells showed about the same number of breaks in alkaline gradients for equal fluence, but only 0.5 alkali-labile bond per true break . Similarly, E . coli DNA with bromouracil irradiated in the cells showed only 10--20% more breaks when denatured with 0.1 M NaOH than under neutral conditions with 9 M sodium perchlorate at 50 degrees C . These results show that true single-strand breaks occur more frequently than alkali-labile bonds after ultraviolet irradiation of DNA containing bromouracil in cells.

Biophys J, 1978 Dec, 24(3), 645 - 56
Double-strand breaks from single photochemical events in DNA containing 5-bromouracil; Krasin F et al.; Ultraviolet irradiation of Escherichia coli cells with a low level of 5-bromouracil incorporated produces DNA double-strand breaks by single photochemical events, one such break per 100 single-strand breaks, the latter assayed in alkali-denatured DNA . About 2.5--4 double-strand breaks are produced per "lethal hit," compared with about 6 double-strand breaks per lethal hit induced by gamma rays . These results are consistent with the hypothesis that an unrepaired DNA double-strand break is a major lethal event in both cases . The increase in sensitivity to ultraviolet (measured by colony-forming ability) seems linear in the number of bromouracils incorporated (0--20% of the thymines), and the linear relationship is much the same for incorporation in one or in both strands of the DNA double helix.

Appl Environ Microbiol, 1978 Dec, 36(6), 972 - 4
Coliform aerosols generated from the surface of dewatered sewage applied to a forest clearcut; Edmonds RL et al.; Concentrations of airborne coliform bacteria as high as 1.5 X 10(4) m-3 were observed 8 cm above anaerobically digested sewage sludge applied to a forest clearcut . Dry conditions and high wind speeds tended to favor aerosol generation.

Transplantation, 1978 Dec, 26(6), 420 - 2
Effect of lipopolysaccharide on the development of cell-mediated immunity to transplantation antigens; Skopinska E; Lipopolysaccharide (LPS) from Escherichia coli administered to allografted mice in a single dose of 20 microgram influenced the development of cell-mediated immunity to skin donor antigens . As an indicator of cell-mediated immunity, donor antigen-induced inhibition of cell migration from spleen explants of allografted animals was used . Cultures of spleen explants were established 16 days after grafting . The antigen-specific inhibition of migration was abolished when LPS was injected either 4 to 2 days before grafting and intensified when LPS was administered on the 2nd day after grafting.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6177 - 81
Temperature-sensitive Escherichia coli mutant producing a temperature-sensitive sigma subunit of DNA-dependent RNA polymerase; Harris JD et al.; A gene affecting the sigma subunit of DNA-dependent RNA polymerase is tightly linked to dnaG at 66 min on the Escherichia coli chromosome . In order to create an easily selectable marker in this region, we inserted transposon-10, which carries a gene determining resistance to tetracycline (tet) near 66 min, and the order tolC-dnaG-sigma-tet was determined . We used frequency of contransduction with tet as a criterion to screen a collection of spontaneous temperature-sensitive Escherichia coli mutants that might affect the sigma subunit . One such mutant was found to map at the sigma locus . The sigma subunit isolated from this mutant is unstable at 46 degrees C in vitro and has an altered electrophoretic mobility . The temperature sensitivity of RNA synthesis in this mutant indicates that most transcription in E . coli is sigma dependent.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6163 - 7
Cluster of ribosomal protein genes in Escherichia coli containing genes for proteins S6, S18, and L9; Isono K et al.; A mutant of Escherichia coli K-12 isolated for temperature-sensitive growth was found to harbor an alteration in robosomal protein L9 . Because the chromosomal location of the structural gene for this protein (rplI) was not known, we mapped the mutation by using various Hfr strains . The fine mapping of this gene by Plkc phage-mediated transductions has revealed that it forms a gene cluster at 94 min on the E . coli genetic map together with the genes coding for two other ribosomal proteins, S6 (rpsF) and S18 (rpsR) . Furthermore, the region of the E . coli genetic map containing this cluster was found to be shorter than previously estimated by approximately 2 min.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6026 - 30
Application of higher derivative techniques to analysis of high-resolution thermal denaturation profiles of reassociated repetitive DNA; Cuellar RE et al.; We have analyzed high-resolution denaturation profiles of reassociated repetitive DNA sequences by using a combination of higher derivative analysis and curve-fitting techniques . Procedures originally used for resolution of components in complex absorption spectra were found to be applicable to high-resolution analysis of melting profiles of reassociated repetitive DNA sequences from pea DNA . Under conditions that eliminate the base composition effect on thermal stability (2.4 M tetraethylammonium chloride), such an anlysis can distinquish "thermal classes" of repetitive DNA duplexes exhibiting different amounts of base pair mismatch . Only a single thermal class is observed in reassociated Escherichia coli DNA whereas at least five classes can be reproducibly distinguished in pea and mung bean DNAs.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5988 - 92
Translational control of transcription termination at the attenuator of the Escherichia coli tryptophan operon; Zurawski G et al.; We have isolated two regulatory mutants altered in the leader region of the Escherichia coli tryptophan (trp) operon . In one mutant, trpL29, the AUG translation start codon for the trip leader peptide is replaced by AUA . The other mutant, trpL75, has a G leads to A change at residue 75, immediately after the UGA translation stop codon for the trp leader peptide . In vivo, trpL29 and trpL75 increase the efficiency of transcription termination at the trp attenuator 3- to 5-fold . trpL29 and trpL75 also fail to respond fully to tryptophan starvation and other conditions that normally relieve transcription termination at the trp attenuator . The trpL29 mutation, which presumably reduces synthesis of the trp leader peptide, is cis dominant . The effect of starvation for a number of the amino acids in the trp leader peptide was determined . Only starvation for tryptophan and arginine, amino acids that occur at residues 10, 11, and 12 of the 14-residue trp leader peptide, elicits relief of transcription termination . Our findings suggest that translation of trp leader RNA is involved in regulation of transcription termination at the attenuator . A model is discussed in which the location of the ribosome synthesizing the leader peptide is communicated to the RNA polymerase transcribing the leader region.

Mayo Clin Proc, 1978 Dec, 53(12), 775 - 81
Chronic peritoneal dialysis in juvenile-onset diabetes mellitus: a comparison with hemodialysis; Mitchell JC et al.; Fourteen juvenile-onset diabetic patients accepted for renal transplantation and maintained on chronic peritoneal dialysis during a 3-year period were compared with a similar group of 43 patients accepted for renal transplantation and maintained on hemodialysis . The 1-year survival in each group was similar (52% on chronic peritoneal dialysis; 55% on hemodialysis), but there was a striking difference in progressive morbidity . Seven patients on chronic peritoneal dialysis were blind in one or both eyes at the onset, and visual acuity improved in two, including one bilaterally blind patient who achieved 20/35 vision bilaterally; none worsened . In the hemodialysis group, 12 patients were totally blind in one or both eyes and 11 additional patients became blind or had severe deterioration in vision; none improved . Neuropathy progressed in only 1 patient on chronic peritoneal dialysis, whereas it worsened in 17 patients on hemodialysis--9 to the extent that they needed braces or canes or were nonambulatory . All patients on chronic peritoneal dialysis were home trained and were dialyzed at night, with seven being able to work full or part time; virtually none of the patients on hemodialysis were able to work . Chronic peritoneal dialysis was relatively free of technical complication, and no significant difficulty was encountered in diabetic control, in the anephric state, or during abdominal surgery . Chronic peritoneal dialysis appears to have less associated morbidity than does hemodialysis in the treatment of chronic renal failure of juvenile-onset diabetes mellitus.

Infect Immun, 1978 Dec, 22(3), 972 - 4
Swiss and inbred mice in the infant mouse test for the assay of Escherichia coli thermostable enterotoxin; Pestana de Castro AF et al.; Swiss and inbred mice (C3H, ASn, B10A, and C57) were used to assay different thermostable enterotoxins prepared from Escherichia coli strains 3 (human), E57 (swine), B41 (cattle), and S13 (sheep) . All strains of mice detected enterotoxins, but some reacted better to a given thermostable enterotoxin preparation than other inbred strains . Since the results obtained with Swiss mice were more consistent than with inbred mice, the former are apparently more suitable in the infant mouse test.

Infect Immun, 1978 Dec, 22(3), 771 - 7
Immunization of suckling pigs against enterotoxigenic Escherichia coli-induced diarrheal disease by vaccinating dams with purified 987 or K99 pili: protection correlates with pilus homology of vaccine and challenge; Morgan RL et al.; Pregnant gilts were vaccinated with purified strain 987 pili (987P), strain K99 pili, or a saline-formaldehyde control . Suckling pigs born to vaccinated gilts were allowed to consume colostrum and were then challenged intragastrically with one of three enterotoxigenic Escherichia coli strains: 987 (O9:K103, 987P:NM), 74-5208 (02O:K101, 987P:NM) or 431 (O101:K30, 99:NM) . In litters where the dam was vaccinated with the same pilus as that possessed by the challenge organism, the incidence and duration of diarrhea and the degree of intestinal colonization (either duration or extent) were less than those of the other vaccine groups . Surviving pigs in the homologous vaccine groups also had better weight gains than pigs in the other vaccine groups . The experiments extend and confirm previous reports that vaccination of the dam with purified pili confers protection to neonatal suckling pigs against diarrheal disease caused by enterotoxigenic E . coli strains that possess the same pili . Protection did not extend to enterotoxigenic strains possessing different pili.

Immun Infekt, 1978 Dec, 6(6), 223 - 5
{Comparative susceptibility testing to sulfamethoxazole and trimethoprim by agar diffusion test on different media (author's transl)}; Freiesleben H et al.; 14 lots of 6 different commercial media for susceptibility testing were compared by agar diffusion test with 161 bacterial strains . The result "resistant" to sulfamethoxazole, trimethoprim, or co-trimoxazole varied in wide limits between the media . The lot employed by the "Work-Group on Resistance" of the Paul Ehrlich Society is of limited value for testing of the investigated drugs.

Cytobiologie, 1978 Dec, 18(2), 309 - 19
Structure of LiCl core particles of 50 S ribosomal subunits from Escherichia coli by electron microscopy; Boublik M et al.; The structure of 50 S E . coli ribosomal subunits was studied by electron microscopy as these particles were gradually depleted of proteins by incubation with 0.5 to 6.0 m LiCl . Changes observed in the structure of the depleted subunits were correlated with the location of the deleted ribosomal proteins on the control 50 S particle . These changes were particularly striking in the "crown" region, the site of a considerable number of the proteins necessary for the biological activity of the 50 S subunit . Protein L 16, the first to be removed by the LiCl treatment, was found to be essential for the structural integrity of the large subunit through interactions with ribosomal proteins residing in the left-hand side crest and the interface . Based on electron microscopic evidence, a scheme was proposed for the structural changes accompanying the stepwise unfolding of the 50 S E . coli subunit by LiCl.

Eur J Biochem, 1978 Dec 1, 92(1), 243 - 51
Identification of cysteine-10 of protein S18 as part of the mRNA-binding site of Escherichia coli ribosomes by affinity-labeling studies with a chemically reactive A-U-G analog; Yaguchi M et al.; The reaction of a bromoacetamidophenyl derivative of the initiation codon A-U-G (A-U-G) with tight couples of Escherichia coli ribosomes leads to an exclusive crosslinking of label to protein S18 . This crosslinking inhibits A-U-G-directed fMet-tRNAfMet binding into the puromycin-sensitive site of ribosomes and stimulates elongation-factor-dependent binding of Met-tRNAmMet . It is, therefore, concluded that protein S18 is located at or near the aminoacyl-tRNA binding site of E . coli ribosomes . Peptide as well as amino acid analysis shows that the reaction between A-U-G and ribosomes took place at cysteine-10 of protein S18 . A-U-G could not be crosslinked to ribosomal proteins of the temperature-sensitive E . coli strain 258ts, where arginine-11 of protein S18 is replaced by a cysteine residue.

Cell, 1978 Dec, 15(4), 1209 - 19
The transposon Tn9 generates a 9 bp repeated sequence during integration; Johnsrud L et al.; We performed a genetic and sequencing analysis of insertions of the transposon Tn9 into the lac operon of E . coli . Genetic mapping of 70 insertions into lacl and Z shows that starting from the same point on the chromosome, Tn9 goes to at least 50 different points in these two genes . Although there are preferred regions for insertion, these consist of multiple integration points within a small area, as demonstrated by pairwise crosses and restriction mapping . Sequence analysis of three Tn9 insertions reveals that Tn9 integration is associated with a direct repeat of 9 base pairs (bp) of host sequence . We show that these extra 9 nucleotide pairs are generated upon insertion and not brought in with the element.

Mutat Res, 1978 Dec, 52(3), 333 - 42
Modification by preirradiation growth conditions of the shoulder of the UV fluence-survival curve of Escherichia coli B/r WP 2 thy trp and changes in mutagenic response toward tryptophan prototrophy; Doudney CO; The distinct three-section UV fluence-mutation frequency response (MFR) curve demonstrated in Escherichia coli strain B/r WP2 thy trp and its uvrA derivative supports the SOS hypothesis and suggests that trp+ revertants can arise either from isolated lesions (1DM) plus SOS induction or from two lesions in proximity (2DM) . Preirradiation growth on arabinose instead of glucose converted the fluence-survival curve from highly shouldered to exponential but did not affect the three-section MFR curve . Prestarvation of the uvrA+ strain for tryptophan, which drastically increases the expanse of the shoulder of the survival curve, greatly decreased both 1DM and 2DM . With the uvrA strain the increase in shoulder expanse after tryptophan prestarvation was accompanied by greatly increased 2DM but no change in 1DM . Preincubation with chloramphenicol induced an even greater increase in 2DM response than amino acid prestarvation . Nalidixic acid, which prevents DNA accumulation, eliminated the response.

Mutat Res, 1978 Dec, 52(3), 323 - 31
Increased UV-inducibility of SOS functions in a dam-3 mutant of Escherichia coli K12 uvrA; Goze A et al.; The dam-3 mutation caused a 2--4 fold increase in the susceptibility of E . coli K-12 uvrA to UV induction of prophage lambda, induced reactivation and mutagenesis of lambda, and mutation to histidine prototrophy . The increased inducibility exceeded the level expected by UV and dam-3 acting additively and independently, and suggests that the effects of UV and dam-3 interact in some way to potentiate induction of SOS functions.

J Bacteriol, 1978 Dec, 136(3), 936 - 46
Metabolism of RNA-ribose by Bdellovibrio bacteriovorus during intraperiplasmic growth on Escherichia coli; Hespell RB et al.; During intraperiplasmic growth of Bdellovibrio bacteriovorus 109J on Escherichia coli some 30 to 60% of the initial E . coli RNA-ribose disappeared as cell-associated orcinol-positive material . The levels of RNA-ribose in the suspending buffer after growth together with the RNA-ribose used for bdellovibrio DNA synthesis accounted for 50% or less of the missing RNA-ribose . With intraperiplasmic growth in the presence of added U-14C-labeled CMP, GMP, or UMP, radioactivity was found both in the respired CO2 and incorporated into the bdellovibrio cell components . The addition of exogenous unlabeled ribonucleotides markedly reduced the amounts of both the 14CO2 and 14C incorporated into the progeny bdellovibrios . During intraperiplasmic growth of B . bacteriovorus on {U-14C}ribose-labeled E . coli BJ565, ca . 74% and ca . 19% of the initial 14C was incorporated into the progeny bdellovibrios and respired CO2, respectively . Under similar growth conditions, the addition of glutamate substantially reduced only the 14CO2; however, added ribonucleotides reduced both the 14CO2 and the 14C incorporated into the progeny bdellovibrios . No similar effects were found with added ribose-5-phosphate . The distribution of 14C in the major cell components was similar in progeny bdellovibrios whether obtained from growth on {U-14C}ribose-labeled E . coli BJ565 or from E . coli plus added U-14C-labeled ribonucleotides . After intraperiplasmic growth of B . bacteriovorus on {5,6-3H-}uracil-{U-14C}ribose-labeled E . coli BJ565 (normal or heat treated), the whole-cell 14C/3H ratio of the progeny bdellovibrios was some 50% greater and reflected the higher 14C/3H ratios found in the cell fractions . B . bacteriovorus and E . coli cell extracts both contained 5'-nucleotidase, uridine phosphorylase, purine phosphorylase, deoxyribose-5-phosphate aldolase, transketolase, thymidine phosphorylase, phosphodeoxyribomutase, and transaldolase enzyme activities . The latter three enzyme activities were either absent or very low in cell extracts prepared from heat-treated E . coli cells . It is concluded that during intraperiplasmic growth B . bacteriovorus degrades some 20 to 40% of the ribonucleotides derived from the initial E . coli RNA into the base and ribose-1-phosphate moieties . The ribose-1-phosphate is further metabolized by B . bacteriovorus both for energy production and for biosynthesis, of non-nucleic acid cell material . In addition, the data indicate that during intraperiplasmic growth B . bacteriovorus can metabolize ribose only if this compound is available to it as the ribonucleoside monophosphate.

J Bacteriol, 1978 Dec, 136(3), 929 - 35
Changes in macromolecular synthesis and nucleoside triphosphate levels during glycerol-induced growth stasis of Escherichia coli; Hennen PE et al.; Experiments were performed to determine how glycerol affects macromolecular syntheses and nucleoside triphosphate levels in a strain of Escherichia coli that lacks a functional sn-glycerol-3-phosphate dehydrogenase . The addition of glycerol to cultures of this strain, Lin 8, growing on a gluconeogenic carbon source causes immediate growth stasis (N . R . Cozzarelli, J . P . Koch, S . Hayashi, and E . C . C . Lin, J . Bacteriol . 90:1325-1329, 1965) . Immediately after the addition of glycerol to cultures of Lin 8, the syntheses of DNA, RNA, and protein are completely inhibited . Phospholipid synthesis is not inhibited as severely by glycerol . The addition of glycerol to strain Lin 8 also results in a rapid decrease in its nucleoside triphosphate levels . The total intracellular concentration of ATP in strain Lin 8 was reduced by 85% within 30 s after the addition of glycerol . These results suggest that the glycerol-induced inhibition of growth and macromolecular syntheses may be a secondary consequence of the decreased energy supply in this strain . In addition, studies also suggest that phospholipid synthesis can continue (albeit at a reduced rate) under conditions of severe energy limitation.

J Bacteriol, 1978 Dec, 136(3), 867 - 73
Mechanism of autoenergized transport and nature of energy coupling for D-lactate in Escherichia coli; Kang SY; To fully energize the active transport systems of Escherichia coli, it is common practice to preincubate the cells for 10 min with 10 or 20 mM concentration of a compound that can serve as an energy source . This paper shows that the active accumulation of D-lactate can be achieved within 1 min with only 50 micron D-lactate serving as an energy source for its own uptake in starved cells (autoenergization) . The cells were strain DL54 which had been induced by growth in the presence of D-lactate . Uninduced cells were not able to show autoenergized D-lactate uptake under these conditions . The induced cells were also able to transport proline in the presence of 100 micron D-lactate as sole energy source . The D-lactate-dependent dehydrogenase activity in inverted French press vesicles was comparable for the induced and uninduced cells . The same was true for respiration of whole cells in the presence of 20 mM D-lactate . However, the Vmax for D-lactate transport of induced cells was six times higher than that of uninduced cells . It appears that a sufficient number of high-affinity carrier molecules in the cytoplasmic membrane are necessary for the autoenergized transport of D-lactate . A similar conclusion was reached for the autoenergized uptake of glycerol-3-phosphate by Escherichia coli strain 7 . The active transport of D-lactate is driven by the protonmotive force.

J Bacteriol, 1978 Dec, 136(3), 839 - 43
Isolation of Escherichia coli mutants with changed regulation of uracil uptake; Fast R; The incorporation of uracil into the pyrimidine ribonucleotide pools of Escherichia coli is strongly restricted under stringent conditions . Previously, we have suggested that this inhibition can be explained by the allosteric properties of uracil phosphoribosyltransferase . It has been proposed that this enzyme performs the uptake of uracil into the cell by transporting it across the cytoplasmic membrane, with the stimultaenous formation of UMP . To test this hypothesis it would be helpful to have mutants with changed regulation of uracil uptake, and in the present work, a method is introduced for the selection of such mutants . This method is based on phenotypic suppression of amber mutations by 5-fluorouracil (5FU) . Mutants were isolated in an arginine-requiring strain of E . coli carrying an amber mutation in argI, the ornithine transcarbamylase gene . To facilitate the phenotypic rescue of this defective gene, mutants which overproduced ornithine transcarbamylase mRNA were isolated as a first step . The absence of exogenously added arginine causes stringent conditions, and phenotypic rescue by 5FU is, thus, prevented, unless the 5FU uptake mechanism is mutationally changed in such a manner that the drug is taken up into the cell . Three mutants in which the growth could be supported by 5FU in the absence of arginine were isolated . Two of them had acquired an increased ability to take up uracil under stringent conditions.

J Bacteriol, 1978 Dec, 136(3), 1189 - 91
Bypass of receptor-mediated resistance to colicin E3 in Escherichia coli K-12; Tilby M et al.; Colicin E3 was found to kill, under conditions of osmotic shock, cells lacking a functional outer membrane receptor (bfe) . Under such conditions, component A of the colicin, carrying endonucleolytic activity, also killed bfe cells, whereas fragment T2, obtained by tryptic digestion of the colicin and also active endonucleolytically, was inactive . Tolerance to the colicin caused by defects in the outer membrane could be overcome by osmotic shock, whereas tolerance probably caused by an altered plasma membrane could not.

J Bacteriol, 1978 Dec, 136(3), 1165 - 73
HindII and HindIII restriction maps of the attphi80-tonB-trp region of the Escherichia coli genome, and location of the tonB gene; Postle K et al.; The HindII and HindIII restriction maps of the attphi80-tonB-trp region of the Escherichia coli chromosome are presented . Analysis of phage DNAs carrying tonB mutations has allowed identification of a 1,730-base pair HindII fragment containing at least part of the tonB gene . This fragment is 4,020 base pairs from the end of trpA, with the total distance from attphi80 to trpA being 6,550 +/- 800 base pairs . Properties of hybrid plasmids containing insertions of various tonB+ restriction fragments suggest that tonB lies completely within the 1,730-base pair fragment . In addition, apparent fusions of beta-galactoside to proteins within the tonB region suggest that the entire region codes for more than one polypeptide.

J Bacteriol, 1978 Dec, 136(3), 1070 - 83
A second transport system for sn-glycerol-3-phosphate in Escherichia coli; Argast M et al.; Strains containing phage Mucts inserted into glpT were isolated as fosfomycin-resistant clones . These mutants did not transport sn-glycerol-3-phosphate, and they lacked GLPT, a protein previously shown to be a product of the glpT operon . By plating these mutants on sn-glycerol-3-phosphate at 43 degrees C, we isolated revertants that regained the capacity to grow on G3P . Most of these revertants did not map in glpT and did not regain GLPT . These revertants exhibited a highly efficient uptake system for sn-glycerol-3-phosphate within an apparent Km of 5 micron . In addition, three new proteins (GP 1, 2, and 3) appeared in the periplasm of these revertants . None of these proteins were antigentically related to GLPT . However, like GLPT, GP1 exhibits abnormal behavior on sodium dodecyl sulfate-polyacrylamide gels . GP 2 is an efficient binding protein . The new uptake system showed different characteristics than the system that is coded for by the glpT operon . It was inhibited neither by phosphate nor fosfomycin . So far, none of the systems that transport organic acids in Escherichia coli could be implicated in the new sn-glycerol-3-phosphate uptake activity . The mutation ugp+, which was responsible for the appearance of the new transport system and the appearance of GP 1, 2, and 3 in the periplasm was cotransducible with araD by phage P1 transduction and was recessive in merodiploids.

J Bacteriol, 1978 Dec, 136(3), 1050 - 7
Repression of synthesis of the vitamin B12 receptor in Escherichia coli; Kadner RJ; Growth of Escherichia coli K-12 strains in the presence of the vitamin cyanocobalamin (B12) resulted in an 80 to 90% reduction in B12 uptake activity of washed cells . Coincident with the decline in uptake activity was the depression of B12-binding activity in energy-poisoned cells, suggesting that growth in B12 resulted in the repression of synthesis of the B12 receptor protein in the outer membrane . Growth in the presence of B12 led to marked reduction in sensitivity to the E colicins, whose adsorption to cells requires the B12 receptor, and to a decrease in the amount of a band on electropherograms of outer membrane proteins . That polypeptide was also missing from mutants altered at btuB, the locus encoding the B12 receptor . Addition of B12 to growing cultures resulted in the exponential decline in specific activity of B12 uptake, as expected for dilution of functional receptors by further growth . Repression of receptor synthesis appears to be regulated by the level of intracellular, rather than extracellular, B12 and is separate from the regulation of the methionine biosynthetic pathway . Mutants altered in btuC, which are defective in accumulation and retention of B12, exhibit a much lower degree of repressibility.

J Bacteriol, 1978 Dec, 136(3), 1008 - 17
dnaT, dominant conditional-lethal mutation affecting DNA replication in Escherichia coli; Lark CA et al.; Normally, bacteria cease DNA replication in the absence of protein synthesis . A variety of treatments, such as thymine starvation or a shift-up to rich medium, lead to continued DNA replication in the absence of protein synthesis . Mutants are described which always terminate replication under these conditions . These conditional lethal mutants, dnaT1 and dnaT2, contransduce with serB and dnaC . The mutation also affects cell division . All aspects of the mutant phenotype (obligatory termination of replication, temperature sensitivity of DNA replication and growth, and aberrant cell division at permissive growth temperatures) were transdominant to the wild-type phenotype . Episomes carrying the dnaT mutation appeared to be unstable . The existence of such a dominant mutation was predicted by a model of chromosome termination proposed by Kogoma and Lark (J . Mol . Biol . 94:243-256, 1975).

Cancer Res, 1978 Dec, 38(12), 4630 - 3
Mode of mutagenic action of methylnitrosocyanamide, a potent carcinogen; Hidaka K et al.; A potent carcinogen, methylnitrosocyanamide was used to induce revertants in a strain of Escherichia coli carrying an amber mutation in a gene for tryptophan (trp) biosynthesis and an ochre mutation in a gene for alkaline phosphatase biosynthesis . Trp+ revertants were purified and classified into seven categories based on their ability to support the growth of particular nonsense mutants of phage lambda and on their content of alkaline phosphatase . About 90% of the Trp+ revertants induced by methylnitrosocyanamide were due to mutations in suppressor genes, and 85% of the suppressor mutations occurred in gene supE . Intragenic reversion cannot occur by a GC leads to AT base substitution mutation, whereas this is the obligate mode of mutation in gene supE . We conclude that methylnitrosocyanamide preferentially induces GC leads to AT transition mutations but that other base substitution mutations are also induced at about 10% of this frequency . N-Methyl-N-nitrosourea and, particularly, N-methyl-N'-nitro-N-nitrosoguanidine also preferentially induce GC leads to AT transition mutations.

Science, 1978 Dec 1, 202(4371), 999 - 1001
Conformational changes in 16S ribosomal RNA induced by 30S ribosomal subunit proteins from Escherichia coli; Bogdanov AA et al.; Laser light scattering has been used to evaluate conformational differences between free 16S RNA and several specific protein-16S RNA complexes . Proteins that interact strongly with the 16S RNA early in subunit assembly stabilize the RNA chain against unfolding in 1 mM Mg2+ and actually promote the formation of a more compact teriary structure in 20 mM Mg2+ . A vital function of these proteins may therfore consist in altering the configuration of the RNA so that further assembly reactions can take place.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 6017 - 20
Repair of O6-methylguanine in adapted Escherichia coli; Schendel PF et al.; Cells exposed to sublethal concentrations of simple alkylating agents develop resistance to their mutagenic effects . This results from the induction of a system that we have called the adaptive response . During exposure to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), Escherichia coli cells induced for the adaptive response accumulate substantially less O6-methylguanine in their DNA than control cells . If O6-methylguanine does form, adapted cells possess a repair system for removing it from their DNA . The capacity of this system is limited and the system ceases to function when too much alkylation has occurred . From this point onwards O6-methylguanine starts to accumulate, and the cells begin to develop mutations at a rate directly proportional to their rate of O6-methylguanine accumulation . Our data support the idea that the O6 methylation of guanine accounts for most MNNG-induced mutagenesis.

J Biochem (Tokyo), 1978 Dec, 84(6), 1401 - 9
Some regulation profiles of ornithine transcarbamylase synthesis in vitro; Dohi M et al.; The regulation profiles of OTCase (argF, argI) synthesis in vitro were investigated by using the in vitro system described in the accompanying paper . Addition of 2.6 mM arginine, crude repressor and partially purified repressor to the in vitro system demonstrated that lambdadargF-DNA-directed OTCase-FFF synthesis is more sensitive to the repressor than lambdapargI-DNA-directed OTCase-III synthesis . The effects of some low-molecular substances on FFF and III syntheses were investigated; guanosine 3'-diphosphate 5'-diphosphate (ppGpp) stimulated both syntheses while cAMP and guanosine 5'-tetraphosphate (Gpppp) were not effective on III synthesis and were slightly inhibitory for FFF synthesis . The substances had no effect on the maturation of the enzyme or on the activity of the enzyme, FFF or III, synthesized . We suggest that argF- and argI-genes are regulated in a slightly different fashion and that the operator-promotor regions are not completely identical for these two genes.

Hoppe Seylers Z Physiol Chem, 1978 Dec, 359(12), 1659 - 65
Photolabile and paramagnetic derivatives of the nucleoside X and of Escherichia coli tRNAPhe; Hansske F et al.; The synthesis of N3-{3-L-(5-azido-2-nitrobenzamido)-3-carboxypropyl}uridine (4b) and N3-{3-carboxy-3-L-(2,2,5,5-tetramethyl-3-pyrroline-3-carbonylamino)propyl}uridine Npyr-oxyl (4c) starting from the nucleoside X (4a) and the appropriate N-hydroxysuccinimide ester 1 or 2 is described . After acylation of tRNAPhe from E . coli (5a) with 1 or 2, the photolabile tRNAPhe derivative 5b and the paramagnetic tRNAPhe derivative 5c could be isolated . The position of modification in the polynucleotide chain was elucidated by comparison of the ribonuclease II/alkaline phosphatase digestion products of the substituted and unsubstituted tRNAPhe samples, and was identified as being exclusively the amino group of the nucleoside X in position 47 of E . coli tRNAPhe.

Eur J Biochem, 1978 Dec, 92(2), 389 - 95
Preferential charging of tRNA-Met-f in Escherichia coli K12; Ron EZ et al.; The charging of tRNA-Met-f and tRNA-Met-m in vivo and in vitro and initiation of polysomes during methionine limitation were studied in two strains of Escherichia coli K12 . In the wild-type strain the distribution of polysomes as well as the kinetic parameters of methionyl-tRNA synthetase indicate preferential acylation of tRNA-Met-f . This preferential charging of tRNAM-et-f does not take place in a mutant strain which is also defective in initiation of polysomes during methionine limitation.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5998 - 6001
Escherichia coli mutants defective in dipeptidyl carboxypeptidase; Deutch CE et al.; Two independent mutants of Escherichia coli deficient in dipeptidyl carboxypeptidase activity (Dep-) were isolated after mutagenesis with ethyl methanesulfonate . Mating experiments and introduction of specific episomes indicated that the responsible gene was located at approximately 27--31 min on the E . coli chromosome . The Dep- mutants differed from the parental strain in their inability to grow with N-acetylalanylalanylalanine as the sole nitrogen source . Revertants selected for growth on this substrate of the enzyme were found to have reacquired the activity . Enzyme activity was highly sensitive to inhibition by 1-(D-3-mercapto-2-methylpropanoyl)-L-proline (SQ 14225), a potent inhibitor of mammalian dipeptidyl carboxypeptidase (angiotensin-converting enzyme, peptidyl dipeptidase, EC 3.4.15.1) . This compound also reduced the rate of growth of the wild type with N-acetylalanylalanylalanine but not with ammonium sulfate . A fraction of the enzyme was released into the medium by osmotic shock, indicating that its presence in the periplasmic space may account for growth with N-acetylated peptides that cannot be taken up by E . coli . In addition to providing information about the specific role of this exopeptidase in E . coli, the Dep- mutants may prove useful for delineating the regulation and cellular function of dipeptidyl carboxypeptidases in higher organisms.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5979 - 82
Refolding of a bifunctional enzyme and its monofunctional fragment; Dautry-Varsat A et al.; The renaturation of the bifunctional enzyme aspartokinase II-homoserine dehydrogenase II has been studied by using the reappearance of its two activities . The same kinetics of renaturation are obtained for the dehydrogenase (EC 1.1.1.3) and the kinase activity (EC 2.7.2.4) . The mechanism of refolding of the enzyme apparently involves two steps, a folding step occurring within a monomer and a subsequent dimerization step . The reappearance of the two activities depends on this dimerization step, suggesting that monomeric species are inactive . A proteolytic fragment possessing full dehydrogenase activity is shown to be able to renature, as judged by the recovery of its activity . In this case also, the refolding depends on the formation of dimeric species . However, the refolding of this fragment is much faster than that of the dehydrogenase region in the intact enzyme . These results suggest that, although the dehydrogenase region can refold by itself when isolated as a fragment, refolding of this same region in the whole protein involves interactions with the remainder of the protein.

Infect Immun, 1978 Dec, 22(3), 644 - 8
Comparative studies of five heat-labile toxic products of Escherichia coli; Konowalchuk J et al.; Five heat-labile, partially purified toxic products of Escherichia coli were distinguished by isoelectric focusing, molecular weight, and neutralization with homologous and heterologous antisera . Only two affected the morphology of Y-1 cells, induced fluid accumulation in rabbit ileal loops, and stimulated production of cyclic AMP in Vero cells; these two did not cross-neutralize and only one showed cross-neutralization with cholera antitoxin . The remaining three products were cytotoxic for Vero cells.

Hosp Pract, 1978 Dec, 13(12), 121 - 7
ELISA: enzyme-linked immunosorbent assay; Yolken RH; Similar in design to radioimmunoassay, comparable in sensitivity and specificity but easier, safer, and less expensive, this new diagnostic technique uses enzyme-labeled rather than isotope-labeled reagents . The end point is a color change that can be assessed by colorimetry or with the naked eye . Various techniques of ELISA are described, along with examples of current and potential clinical applications.

Mutat Res, 1978 Dec, 52(3), 301 - 11
Perturbations in simian virus 40 DNA synthesis by ultraviolet light; Williams JI et al.; Perturbations of Simian Virus 40 (SV40) DNA replication by ultraviolet (UV) light during the lytic cycle in permissive monkey CV-1 cells resemble those seen in host cell DNA replication . Formation of Form I DNA molecules (i.e . completion of SV40 DNA synthesis) was more sensitive to UV irradiation than synthesis of replicative intermediates or Form II molecules, consistent with inhibition of DNA chain elongation . The observed amounts of {3H}thymidine incorporated in UV-irradiated molecules could be predicted on the assumption that pyrimidine dimers are responsible for blocking nascent DNA strand growth . The relative proportion of labeled Form I molecules in UV-irradiated cultures rapidly increased to near-control values with incubation after 20 or 40 J/m2 of light (0.9--1.0 or 1.8--2.0 dimers per SV40 genome, respectively) . This rapid increase and the failure of Form II molecules to accumulate suggest that SV40 growing forks can rapidly bypass many dimers . Form II molecules formed after UV irradiation were not converted to linear (Form III) molecules by the dimer-specific T4 endonuclease V, suggesting either that there are no gaps opposite dimers in these molecules or that T4 endonuclease V cannot use Form II molecules as substrates.

J Bacteriol, 1978 Dec, 136(3), 1201 - 4
Effects of altered rho gene product on the expression of the Escherichia coli histidine operon; Lawther RP et al.; An altered rho gene product affects expression of the his operon of Escherichia coli . The effect is greater for the operator proximal portion of the his operon than for the operator distal portion . This "rho effect" appears to be independent of the site of action of hisT-altered histidyl-tRNA.

J Biochem (Tokyo), 1978 Dec, 84(6), 1513 - 7
Coupling factor ATPase from Escherichia coli . An uncA mutant (uncA401) with defective alpha subunit; Kanazawa H et al.; Inactive coupling factor ATPase (F1) was prepared from an uncoupled mutant (uncA401) of Escherichia coli . Reconstitution of ATPase activity was observed when alpha subunit from wild-type F1 was added to the dissociated inactive F1 and the mixture was dialyzed against buffer containing ATP and Mg2+ . ATPase was also reconstituted when the mixture of alpha subunit (wild type) and crude extract from the mutant was dialyzed against the same buffer . These results indicate that the mutant is defective in alpha subunit, suggesting that the uncA401 locus carries the structural gene for alpha subunit, and that this polypeptide plays an essential role in ATPase activity in F1 molecule.

J Biochem (Tokyo), 1978 Dec, 84(6), 1453 - 8
Myosin and actin from Escherichia coli K12 C600; Nakamura K et al.; Myosin-like protein and actin-like protein from E . coli formed filaments very similar in structure to those of myosin and actin from skeletal muscle . At 0.2 M KCl, a large number of "thick filaments" of uniform size (about 0.6-0.7 micron long and about 20 nm wide) was present . These thick filaments aggregated as the KCl concentration decreased to less than 0.2 M . Filaments of actin-like protein were decorated with muscle heavy meromyosin, showing "arrowheads" . The arrowhead structure disappeared in the presence of ATP . A mixture of E . coli myosin-like protein and rabbit skeletal actin exhibited a gelation phenomenon on the additon of ATP . The phenomenon was reversible and showed ATP specificity . However, the gelation phenomenon was not observed with the mixture of E . coli actin-like protein and E . coli myosin-like protein . These results provide compelling evidence that the E . coli myosin-like protein and actin-like protein we isolated are essentially identical to myosin and actin, respectively.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5960 - 3
DNA gyrase: subunit structure and ATPase activity of the purified enzyme; Mizuuchi K et al.; DNA gyrase has been purified to near homogeneity from Escherichia coli . The enzyme consists of two subunits of molecular weights 90,000 and 100,000 present in roughly equimolar amounts . The subunits can be identified as the products of two genes, determining resistance to coumermycin A1 and novobiocin (cou) and to nalidixic acid and oxolinic acid (nalA), respectively . These antibiotics were previously shown to be specific inhibitors of DNA gyrase . The ATPase activity of DNA gyrase is stimulated by double-stranded DNA and strongly inhibited by novobiocin but is relatively insensitive to oxolinic acid . Covalent attachment of an ATP derivative to the smaller (coumermycin-specific) subunit is also inhibited by novobiocin, suggesting that this drug interferes with the energy-coupling aspect of the DNA supercoiling reaction by blocking the access of ATP to the enzyme.

Genetics, 1978 Dec, 90(4), 673 - 81
Regulation of newly evolved enzymes . IV . Directed evolution of the Ebg repressor; Hall BG; In Escherichia coli, the wild-type repressor of ebg (evolved beta-galactosidase) enzyme synthesis, specified by the ebgR+ gene, responds very weakly to lactulose (fructose-beta-D-galactopyranoside) . Selection for a functional repressor that responds strongly to lactulose as an inducer reveals the existence of ebgR+L mutants, which occur spontaneously at a frequency of about 2 X 10(-10) . EBGR+L mutants are pleiotropic in that they specify ebg repressor with a greatly increased response to lactulose, lactose, galactose-arabinoside and methyl-galactoside as inducers . Selection of ebgR+L mutants is discussed within the framework of directed evolution of a regulatory function.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5936 - 40
Chicken ovalbumin is synthesized and secreted by Escherichia coli; Fraser TH et al.; By recombinant DNA methods, the chicken ovalbumin structural gene has been fused to Escherichia coli lac transcriptional and translational control regions . When a plasmid containing the hybrid gene was introduced into E . coli, a protein identified as ovalbumin by immunoreactivity and sodium dodecyl sulfate/polyacrylamide gel electrophoresis was synthesized . The chicken ovalbumin made in bacteria was full length (43,000 daltons) and constituted 1.5% of the cellular protein . In addition, the microbially synthesized ovalbumin was secreted through the cell membrane into the periplasmic space of E . coli . The ability of the E . coli secretory apparatus to recognize chicken ovalbumin, which is normally synthesized and secreted in hen oviducts, suggests that common features exist in the secretion-recognition mechanisms found in these two organisms . The bacterial synthesis of significant amounts of chicken ovalbumin demonstrates that the E . coli cellular machinery may be utilized to synthesize a higher eukaryotic protein which is relatively stable in the bacterial intracellular environment.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5869 - 73
Isolation and characterization of ColE1-derived plasmid copy-number mutant; Gelfand DH et al.; The plasmid pBGP120 is a ColE1 derivative that contains elements of the Escherichia coli lac operon and the Tn3 transposon . We have selected and isolated a copy-number mutant of pBGP120 . In exponentially growing cultures, the copy-number mutant, pOP1, represents approximately 30% of total intracellular DNA compared to about 5% for pBGP120 . Plasmid-encoded beta-galactosidase monomer can represent 50% of newly synthesized protein in cells carrying pOP1 . pOP1 is structurally unstable in certain genetic backgrounds and under certain growth conditions, breaking down to a smaller sized plasmid that retains the DNA overproducer phenotype and the Tn3 transposon . The smaller overproducer plasmid, pOP1delta6, is generated by a continuous deletion of sequences located between one end of the Tn3 transposon and a site about 630 nucleotides from the EcoRI site in the beta-galactosidase structural gene of pOP1 . pOP1delta6 retains the ColE1 origin of replication but has lost the lac promotor and operator and most of the beta-galactosidase structural gene . pOP1delta6 exists at approximately 210 copies per chromosome in exponentially growing cells.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5802 - 6
Mutations altering the cellular localization of the phage lambda receptor, an Escherichia coli outer membrane protein; Emr SD et al.; Two mutant strains of Escherichia coli have been isolated in which the cellular location of an outer membrane protein, the phage lambda receptor (the lamB gene product), is altered . These mutations were initially selected in a strain containing a lamB-lacZ fusion . In the parent strain the protein coded for by the hybrid gene is located, at least in part, in the outer membrane . In the mutants it is located in the cytoplasm . The mutations responsible for the alteration of cellular location lie very early in the lamB gene, in a region corresponding to the NH2-terminus of the lambda receptor protein . One of these mutations is a small deletion internal to the lamB gene . When this mutation is present in an otherwise wild-type lamB gene, the protein produced is of lower molecular weight than normal receptor . The other mutation behaves as a point mutation; when it is present in an otherwise normal lamB gene, reversion can be demonstrated . The molecular weight of this mutant protein, which is located in the cytoplasm, is larger than that of the wild-type gene product by approximately 2000 . It is suggested that these two mutations are in the portion of the lamB gene coding for a signal sequence and thereby block export of the protein.

Infect Immun, 1978 Dec, 22(3), 852 - 60
Purification of heat-labile enterotoxin from four Escherichia coli strains by affinity immunoadsorbent: evidence for similar subunit structure; Dafni Z et al.; A single-step method for the purification of heat-labile enterotoxin of Escherichia coli is described . The method involves an affinity immunoadsorbent made with antiserum to cholera toxin . Crude toxin preparations of three human and one porcine enterotoxinogenic strains of E . coli were purified on this immunoadsorbent, and the elution products suggest that the toxin molecule is composed of subunits . One kind of subunit shared by these four strains showed similar mobility of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, close antigenic relationship, and an antigen in common with cholera enterotoxin.

Eur J Biochem, 1978 Dec 1, 92(1), 235 - 41
Translation of MS2 RNA in vitro in the absence of initiation factor IF-3; Zipori P et al.; An Escherichia coli cell-free translational system, deprived of initiation factor IF-3, has been used to study the role of the factor in protein synthesis . In this system, 30-S ribosomal subunits are preincubated together with MS2 phage RNA in a small volume in the presence of 10 mM Mg(Ac)2; the missing components required for protein synthesis are then added and assembly of elongating ribosomes is allowed to occur . This stepwise assembly process permits formation of functional complexes which can carry out protein synthesis in the complete absence of IF-3 . The translational products, obtained in the absence of IF-3, have been analysed and shown to be similar to those synthesized in the presence of the factor . The main product observed is the phage coat protein.

Proc Natl Acad Sci U S A, 1978 Dec, 75(12), 5983 - 7
Interaction of bleomycin with DNA; Takeshita M et al.; The sequence of oligonucleotides produced by the action of bleomycin and ferrous ion on double- and single-stranded DNA has been determined . In the presence of ferrous ion, bleomycin promotes cleavage at G-T and G-C sequences, while high concentrations of ferrous ion alone result in strand scission that is not base specific . In the presence of bleomycin and ferrous ion, pyrimidine bases located to the 3' side of guanosine are released preferentially and a low molecular weight product that forms a chromophore with thiobarbituric acid is produced from the deoxyribose moiety . Oligonucleotides produced by the action of bleomycin differ slightly in electrophoretic mobility from those produced by chemical or enzymatic cleavage . A model is proposed to explain the interactions of bleomycin with DNA.

Chem Biol Interact, 1978 Dec, 23(3), 399 - 407
Effects of benzo(a)pyrene adducts of DNA synthesis in vitro; Yamaura I et al.; Two diol epoxides of benzo(a)pyrene (BP), and benzo(a)pyrene 4,5-oxide, have been used to make adducts in the homopolymers polyribocytidylic acid, (rC); polyriboadenylic acid (rA), polydeoxycytidylic acid (dC) and polydeoxyadenylic acid (dA) . With appropriate oligomers as primers these modified and unmodified polynucleotides were used as templates for DNA synthesis with avian myeloblastosis virus DNA polymerase (AMV) or E . coli Pol I DNA polymerase . We have found that: (1) the size of the DNA product is not markedly decreased by the presence of these these polycyclic aromatic hydrocarbon adducts in the templates; (2) the presence of adducts does not lead to increased incorporation of erroneous bases . These results, supported by kinetic data, suggest that these polymerases can bypass a site containing an adduct on the template without leaving a gap or causing misincorporation of a base and they imply that mutagenesis by BP may not be attributable to either of these mechanisms.

Immunopharmacology, 1978 Dec, 1(1), 39 - 47
Quantitative comparisons of various biological responses of neutrophils to different active and inactive chemotactic factors; Kreutzer DL et al.; The effects of chemotactic factors on rabbit neutrophils were evaluated measuring cell migration in modified Boyden chambers and under agarose, in lysosomal enzyme release, leukocyte aggregation, and in vivo neutropenia . Chemotactins employed included the complement-derived C3 and C5 fragments, the bacterial chemotactic factor from culture supernatant fluids of Escherichia coli, and the synthetic chemotactic factors Met-Leu-Phe and formyl-Met-Leu-Phe . A consistent parallelism was found in all the leukocyte responses to a given chemotactic factor . In no instance, with any of the five chemotactic factor preparations, did cells responding in one assay system fail to respond in the four other assay systems, suggesting a common event in all of the cell responses . Boyden chamber chemotaxis was consistently the most sensitive assay; the agarose assay was, in general, less sensitive by a factor of 100 fold . Enzyme release approached, in cell sensitivity to chemotactic factors, that of the Boyden chamber assay . In general, in vitro leukocyte aggregation and in vivo neutropenia were considerably less sensitive assays . Chemotactic factor inactivator (CFI) purified from human serum destroyed in parallel all biological activities of C3 and C5 chemotactic factors but had no effect on the bacterial chemotactic factor and the activities of synthetic chemotactic peptides.

J Biochem (Tokyo), 1978 Dec, 84(6), 1641 - 3
Transport of nicotinamide adenine dinucleotide in an unc mutant of Escherichia coli; Murakawa S et al.; The presence and some properties of an NAD+ transport system were examined in PA5, a Mg, Ca-ATPase {EC 3.6.1.3}-defective mutant strain of Escherichia coli W2252 . NAD+ uptake was stimulated by exogenous energy sources and dependent on external substrate concentrations with an apparent Km of about 25 micrometer . Most of the radioactivity from {14C}-NAD+ accumulated in the cells was identified as NAD+ . {14C}NAD+ uptake was competively inhibited by unlabeled NAD+, NADP+, NMN+ or nicotinamide . Similar uptake activity was also observed in W2252.

Eur J Biochem, 1978 Dec, 92(2), 613 - 9
Protons and Mg2+ cations as probes in investigating the role of GTP in initiation complex formation; Beaudry P et al.; fMet-tRNAfMet binding to both 30-S subunits and to 70-S particles is dependent on both pH AND Mg2+ concentration: for fMet-tRNAfMet binding to 70-S particles, variations of pH and Mg2+ concentration are tightly interdependent . This behavior can be interpreted by the polyelectrolyte theory as a direct consequence of the fact that the binding occurs in a polyanionic micro-environment . The pH-dependent binding to 70-S particles clearly shows the involvement of two prototropic groups which appear to be those carrying out GTP hydrolysis, therefore directly linked to initiation complex formation; in the presence of a non-hydrolyzable analogue to GTP, guanosine 5'-{beta, gamma-imido}triphosphate, the binding of fMet-tRNAfMet shows much less interdependence between variation of pH and Mg2+ concentration.

Fed Proc, 1978 Dec, 37(14), 2775 - 82
Enzyme reactions of ATP studied by positional isotope exchange; Rose IA; Reversible gamma-PO3 transfer in ATP reactions can be recognized by exchange of 18O from the beta,gamma-bridge position to the beta-P-nonbridge positions: (see article) . Such intramolecular exchange is less demanding for the detection of the bond cleavage than the usual ATP:ADP isotope exchange because it does not require dissociation of bound ADP from the intermediate complex . Acyl phosphate intermediates are indicated for the glutamine synthetase and carbamyl-P synthetase reactions by their extreme requirements for glutamate and bicarbonate, respectively, for positional oxygen exchange . No support is given for E-P or concerted mechanisms . No support is found for an active CO2 in the latter reaction, although this is not ruled out by the data . Positional isomerization in ATP occurs with lamellae from spinach chloroplast only in the light . When the ATP molecule interacts, it also undergoes complete exchange of the gamma-PO3 oxygen with water before it rejoins the pool of free ATP . The difference in rates of the two exchanges suggests that the torsional motion of ADP-beta-PO3 is greatly hindered on the enzyme . This may explain, by the argument of substrate activation, the rapid reversibility of the ATPase reaction on the enzyme.

Mol Gen Genet, 1978 Nov 29, 167(2), 227 - 34
A site of action for tRNA mediated regulation of the ilvOEDA operon of Escherichia coli K12; Lawther RP et al.; Transfer RNA (tRNA), rho factor threonine deaminase and the ilvO locus are molecular participants in the regulation of isoleucine-valine (ilv) biosynthesis . Isogenic strains have been constructed with the hisT76 mutation in pairwise combination with ilvO mutations, the rho221 mutation and the ilvDAC115 deletion mutation . The role of the altered tRNA of the hisT76 mutation was found to be independent of the sites of action of the ilvO- mutation, rho factor, and threonine deaminase . The expression of the ilvOEDA operon is stimulated 2-fold when the hisT76 mutation is present in strains containing either ilvO- or rho221 mutations . The expression of the ilvOEDA operon remains nonrepressed in a hisT76 strain deleted for threonine deaminase . These results indicate that the hisT76 undermodified tRNAs are influencing the initiation of transcription of the ilvOEDA operon.

Mol Gen Genet, 1978 Nov 29, 167(2), 209 - 15
Uv-inducible repair II: its role in various defective mutants of Escherichia coli K-12; Sedliakova M et al.; Involvement of UV-inducible protein(s) in repair of various E . coli K-12 cell strains has been investigated using a procedure of double UV irradiation and postincubation with chloramphenicol . From the course of dose survival curves the following conclusions concerning significance of a UV-inducible protein have been drawn: 1 . It is a very important for wild type cells; in these cells its early occurrence is necessary to prevent killing . 2 . It is involved in repair of excision-deficient cells; however, its action early after UV is less urgent . 3 . It is not involved at all in repair of lex mutant cells; 4 . It exhibits some effect on survival of recA as well as recB mutant cells . We conclude that the protein is involved in excision repair as well as in resumption of DNA replication.

Mol Gen Genet, 1978 Nov 29, 167(2), 129 - 37
Lambda transducing phages for the nalA gene of Escherichia coli and conditional lethal nalA mutations; Kreuzer KN et al.; Defective lambda transducing phages for the nalA region of the Escherichia coli chromosome were isolated from a lysogen in which lambda is inserted in the nearby glpT gene . The three classes of transducing phages designated lambdanrdA, lambdaubiG, and lambdadnalA contained bacterial DNA extending from glpT through nrdA, ubiG, and nalA, respectively . The bacterial genes are in the left arm of the lambda chromosome . Of the eleven polypeptides coded by lambdadnalA that were resolved by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate only one was not also specified by lambdadubiG . This 105,000 dalton polypeptide is the nalA gene product . The electorphoretic mobility and isoelectric point of this protein were unaffected by a nalA mutation (nalA48) that confers nalidixic acid resistance . Temperature-sensitive and amber mutations in the nalA gene were isolated using a lambdadnalA48 lysogen which is heterodiploid for nalA . The conditional lethality of these mutations proves that nalA is an essential locus.

Biochemistry, 1978 Nov 28, 17(24), 5141 - 6
Subunit dissociation in the allosteric regulation of glycerol kinase from Escherichia coli . 2 . Physical evidence; de Riel JK et al.; The dependence of the molecular weight of glycerol kinase on enzyme concentration and on binding of fructose 1,6-bisphosphate has been examined by velocity sedimentation, gel filtration, and polyacrylamide gel electrophoresis . The sedimentation coefficient and Stokes radius decrease as a consequence of dilution in a manner consistent with dissociation into half-molecules, with limiting values suggesting molecular weights of about 218,000 and 136,000 for the associated and dissociated species, respectively . Fructose 1,6-bisphosphate (5 mM) prevents the decrease in sedimentation coefficient brought about by dilution, suggesting a decrease in the apparent subunit dissociation constant of at least four orders of magnitude . Electrophoretic mobility in polyacrylamide gels increases as a consequence of dilution in the absence, but not in the presence, of fructose 1,6-bisphosphate . Ferguson plots indicate that glycerol kinase has the same molecular weight in the presence of fructose 1,6-bisphosphate as the covalently cross-linked tetramer and is substantially smaller in the absence of fructose 1,6-bisphosphate . These results are consistent with the model of glycerol kinase proposed in the preceding paper of this issue {de Riel, J.K., and Paulus, H . (1978), Biochemistry 17} relating subunit dissociation and ligand binding.

Biochemistry, 1978 Nov 28, 17(24), 5160 - 4
Probe of beta-galactosidase structure with iodoacetate . Differential reactivity of thiol groups in wild-type and mutant forms of beta-galactosidase; Jornvall H et al.; Carboxymethylation with 14 C-labeled iodoacetate of cysteine residues in wild-type beta-galactosidase from Escherichia coli and in a defective beta-galactosidase from deletion mutant strain M15 was investigated in order to determine accessible positions in the tetrameric wild-type form and the dimeric mutant M15 protein . The extent of carboxymethylation, the effects on biological activity, antibody activation, physical stability, and the labeling of particular residues were studied . The results distinguish three groups of spatial relationships for cysteine residues in the protein, define possible regions for subunit interactions, and confirm that no cysteine residue is specifically involved in catalysis . Residue 1019 and to a lesser extent 498 are accessible in the tetrameric protein and probably represent exposed areas . In the M15 protein, these two, and three additional residues, at 76,387 and 600, were found to react significantly with reagent . One or more of the latter are suggested to be in the dimer-dimer interface . Complementation and activation by antibody are inhibited by carboxymethylation of M15 protein.

Biochemistry, 1978 Nov 28, 17(24), 5146 - 50
Subunit dissociation in the allosteric regulation of Glycerol kinase from Escherichia coli . 3 . Role in desensitization; de Riel JK et al.; The mechanism of desensitization of glycerol kinase to allosteric inhibition by fructose 1,6-bisphosphate caused by salt, urea, and high pH has been examined in the light of the model proposed in an earlier paper {de Riel, J . K., and Paulus H . (1978), Biochemistry 17} relating subunit dissociation and ligand binding . KCl (0.4 M) causes a tenfold decrease in the affinity of tetrameric glycerol kinase for fructose, 1,6-bisphosphate but has no significant effect on the dissociation process itself . Urea (2 M) causes a large increase in the equilibrium constant for the dissociation of the glycerol kinase tetramer to dimer but has no effect on the affinity of the tetramer for the allosteric inhibitor . High pH (9--10) has only a small effect on the subunit dissociation constant but greatly reduces the rates of subunit association and dissociation . Desensitization of glycerol kinase to allosteric inhibition can thus occur by three different mechanisms, two of which are directly related to the polysteric nature of the enzyme.

C R Acad Sci Hebd Seances Acad Sci D, 1978 Nov 27, 287(15), 1349 - 50
{Procaine, a local anesthetic, interacting with the cell membrane and inhibiting the processing of exported protein precursors in Escherichia coli}; Lazdunski C et al.; In E . coli cells grown in the presence of procaine (0.55% w/v), precursor forms of alkaline phosphatase and of glutamine binding protein accumulate besides mature forms synthesized prior to procaine addition . An experimental technique, of general application, for isolation and purification of mature and precursor forms obtained under these conditions, is described.

Vet Rec, 1978 Nov 25, 103(22), 482 - 5
Pathological features of multiple bone infection in the foal; Bennett D; The gross and histological features of multiple bone infection in two foals are described . In both cases the lesions were confined to the region of the growth plate . Bone and, in some cases, growth plate cartilage destruction has occurred associated with an extensive inflammatory cell infiltration . The significance of the pathological observation is discussed in relation to the pathogenesis of bone infection in the foal.

J Biol Chem, 1978 Nov 25, 253(22), 8213 - 20
Phospholipid composition and membrane function in phosphatidylserine decarboxylase mutants of Escherichia coli; Hawrot E et al.; Temperature-sensitive conditional lethal mutants in phosphatidylserine decarboxylase (psd) accumulate large amounts of phosphatidylserine under nonpermissive conditions (42 degrees C) prior to cell death . In addition, the ratio of cardiolipin to phosphatidylglycerol is increased . At an intermediate temperature (37 degrees C), high levels of phosphatidylserine can be maintained with little effect on cell growth or viability . Under these conditions, both the rate of induction and the function of the lactose transport system are normal . At 42 degrees C addition of Mg2+ or Ca2+ to mutant cultures produces a partial phenotypic suppression . Growth is prolonged and the filaments normally present at 42 degrees C do not form . Upon transfer to the nonpermissive temperature, there is a considerable lag before accumulation of phosphatidylserine begins and the growth rate is affected . Based on the kinetics of heat inactivation of phosphatidylserine decarboxylase activity in extracts, in intact nongrowing cells, and in growing cells, it appears that the enzyme newly synthesized at 42 degrees C is more thermolabile in vivo than enzyme molecules previously inserted into the membrane at the lower temperature . Thus, the older, stable enzymatic activity must be diluted during growth before physiological effects are observed.

J Biol Chem, 1978 Nov 25, 253(22), 8061 - 4
Partial reactions of aminoacyl-tRNA synthetases as functions of pH; Lui M et al.; The effect of pH on the properties of the partial reactions of arginyl-tRNA synthetase of E . coli has been investigated . V max of pyrophosphorolysis of arginyl adenylate has a pH optimum at pH 6.1, whereas V max of the transfer of arginine to tRNA has a pH optimum of 8.2 . These values correlate with the pH optima of the ATP:PPi exchange and the overall esterification reaction, respectively . Only the pyrophosphorolysis reaction requires a divalent cation; transfer proceeds in the presence of EDTA . Inorganic pyrophosphate inhibits the transfer reaction to an extent independent of the concentration of tRNA; the maximum inhibition is a function of pH, corresponding to the relative rate of pyrophosphorolysis of the common intermediate compared with the rate of transfer . These results show that different groups on the enzyme participate in the rate-limiting steps of the two partial reactions and that these partial reactions have properties consistent with their participation in the overall esterification of arginine with tRNA.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 144 - 54
Induction and repair of strand breaks and 3'-hydroxy terminals in the DNA of mouse brain following gamma irradiation; Yoshizawa K et al.; DNA was isolated from mouse brain after in vivo gamma-ray irradiation, treated with endonuclease S1 from Aspergillus oryzae if necessary, and analysed further by alkaline and neutral sucrose gradient centrifugation . In parallel, its template activity was determined by DNA polymerase (EC 2.7.7.7, enzyme A of Klenow from Escherichia coli) assay as described previously . Similar experiments were performed with cultured mouse leukaemia cells (L5178Y) irradiated in vitro at 0 degrees C . Irradiation induced single- and double-strand breaks in the DNA of the brain with a yield of 1.0 and 0.1 break per 10(12) dalton per rad (100 eV/break and 770 eV/break), respectively . The yield of single-strand breaks in the brain was lower than that found in the cultured cells, whereas the yield of double-strand breaks was found to be almost the same in both cases . Treatment of irradiated DNA with single-strand-specific S1 endonuclease gave rise to further breaks detected on neutral sucrose gradient analysis . The yield of these breaks was also higher in the brain compared to the cultured cells . The increase per unit dose in the template activity of the DNA from the brain was found to be five times as much as that found in the cultured cells . Then, the average number of deoxyribonucleotides incorporated per break was determined on DNA which had experienced different treatments . The value for the brain DNA irradiated in vivo was found to be five times as much as that found for DNA treated with pancreatic deoxyribonuclease and 10 times as much as those found for DNA from the cultured cells and isolated brain nuclei irradiated in vitro at 0 degrees C . Thus, in vivo irradiation seemed to induce gaps with 3'-OH terminals in addition to simple breaks with or without 3'-OH terminals found in the cultured cells . Radiation-induced single-strand breaks and 3'-OH terminals in the DNA of the brain were repaired following irradiation . Approx . 20--40% of the terminals or breaks induced were, however, remaining at 3 h or more after irradiation, depending on the dose administered.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 67 - 73
The kinetic complexity of Acetabularia chloroplast DNA; Padmanabhan U et al.; The kinetic complexity of Acetabularia cliftonii chloroplast DNA is 1.52 +/- 0.26 . 10(9) daltons, compared to 0.2 .10(9) daltons for Chlamydomonas chloroplast DNA . There is an average of three genomes per chloroplast . The unusually large size of the Acetabularia genome may reflect the ancient evolutionary history of this organism.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 308 - 23
A large nucleoprotein fragment of the 50-S ribosomal subunit of Escherichia coli; Spitnik-Elson P et al.; A large nucleoprotein fragment was isolated from a nuclease digest of Escherichia coli 50-S ribosomes and purified to gel electrophoretic homogeneity . Conditions were employed under which the fragmentation pattern was reproducible and the various fragment fractions were stable and maintained their sedimentation and electrophoretic properties throughout the several preparative and analytical procedures used . Fractions that appeared homogeneous in sucrose gradient centrifugation were found to be heterogeneous by gel electrophoresis . The large fragment was purified to homogeneity by preparative gel electrophoresis . It contained 21 proteins, the 5-S RNA, and two large oligonucleotides which together total about two thirds the molecular weight of the 23-S RNA . Because it can be prepared reproducibly in large quantities and because of its size and stability, the fragment appears suitable for functional and structural studies and as the starting material for further fractionation . An important contributing factor to the observed stability and reproducibility was the maintenance of an unchanging ionic environment . A single buffer was employed throughout all the procedures, and the fragments produced by nuclease digestion were dissociated from each other by heat rather than by changing the medium.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 117 - 25
Specific interaction between mouse liver non-histone chromosomal proteins and mouse DNA demonstrated by a sequential DNA-protein binding procedure; Lesser BH et al.; The binding of mouse liver chromosomal proteins to DNA has been investigated using the nitrocellulose filter binding technique . Careful purification of the DNA involving nuclease S1 digestion and prefiltration through a nitrocellulose filter is used to reduce background binding in the absence of protein to less than 1% . Procedures involving direct binding of protein to labeled DNA, competition of binding of labeled DNA by unlabeled DNA, and dissociation of DNA . protein complexes with time do not indicate significant preference for binding to mouse DNA relative to Escherichia coli DNA . This specificity is demonstrated much more clearly by a novel type of procedure, which we call a sequential binding procedure . In this procedure non-specific binding proteins are sequestered by incubation with an excess of unlabeled E . coli DNA prior to addition of labeled DNA . Under these conditions, labeled mouse DNA is bound to filters to a 3- to 4-fold greater extent than labeled E . coli DNA.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 169 - 86
The organization of ribosomal RNA genes in the mitochondrial DNA of Tetrahymena pyriformis strain ST; Goldbach RW et al.; 1 . We have constructed a physical map of the mtDNA of Tetrahymena pyriformis strain ST using the restriction endonucleases EcoRI, PstI, SacI, HindIII and HhaI . 2 . Hybridization of mitochondrial 21 S and 14 S ribosomal RNA to restriction fragments of strain ST mtDNA shows that this DNA contains two 21-S and only one 14-S ribosomal RNA genes . By S1 nuclease treatment of briefly renatured single-stranded DNA the terminal duplication-inversion previously detected in this DNA (Arnberg et al . (1975) Biochim . Biophys . Acta 383, 359--369) has been isolated and shown to contain both 21-S ribosomal RNA genes . 14 S ribosomal RNA hybridizes to a region in the central part of the DNA, about 8000 nucleotides or 20% of the total DNA length apart from the nearest 21 S ribosomal RNA gene . 3 . We have confirmed this position of the three ribosomal RNA genes by electron microscopical analysis of DNA . RNA hybrid molecules and R-loop molecules . 4 . Hybridization of 21 S ribosomal RNA with duplex mtDNA digested either with phage lambda-induced exonuclease or exonuclease III of Escherichia coli, shows that the 21-S ribosomal RNA genes are located on the 5'-ends of each DNA strand . Electron microscopy of denaturated mtDNA hybridized with a mixture of 14-S and 21-S ribosomal RNAs show that the 14 S ribosomal RNA gene has the same polarity as the nearest 21 S ribosomal RNA gene . 5 . Tetrahymena mtDNA is (after Saccharomyces mtDNA) the second mtDNA in which the two ribosomal RNA cistrons are far apart and the first mtDNA in which one of the ribosomal RNA cistrons is duplicated.

Biochim Biophys Acta, 1978 Nov 21, 521(1), 126 - 33
Specificity of DNA base release by bleomycin; Povirk LF et al.; DNA was treated with bleomycin in the presence of Fe2+ and 2-mercaptoethanol under conditions where only a few percent of the bases were released . Release of all four bases was a linear function of bleomycin concentration, but the amount of thymine released was twice that of cytosine, 7 times that of adenine, and twelve times that of guanine . Unidentified minor products of thymine, of cytosine and of a purine were also released . Bromouracil did not sensitize DNA to bleomycin-induced breakage, and was released at the same rate as thymine.

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