Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| bacteriophage t4 riib protein synthesis with a temperature-sensitive mutation in the riib initiation codon. | in protein synthesis, the incorporation of an n-terminal formylmethionine residue is directed by an initiation codon. the most frequently used codon is aug, although initiation at gug and uug codons has also been observed. the hd263 mutation is an aug to aua change in the riib initiation codon. evidence is presented here that wild type and hd263 riib proteins, whether synthesized in vivo or in vitro, have identical fmet peptides. it is concluded that translation began at the aua mutant initiatio ... | 1979 | 286150 |
| dna replication by bacteriophage t4 proteins: role of the dna-delay gene 61 in the chain-initiation reaction. | 1979 | 289458 | |
| in vivo interactions of genes and proteins in dna replication and recombination of phage t4. | 1979 | 289460 | |
| late replication and recombination in the vegetative pool of t4. | the rates and extents of replication are the same for all members of the vegetative pool, whether already residing (progeny) or newly entered (superinfecting). thus, no member of the pool is sequestered in a replicative complex. amber n82 infections of nonpermissive host result in extensive breakdown of phage dna. the extent of fragmentation observed depends on the multiplicity of infection and whether phage ligase is present. hence, parental dna suffers single-strand nicks which can be repaired ... | 1979 | 289461 |
| a screening programme for congenital hypothyroidism: preliminary results. | highly sensitive and precise radioimmunoassays for thyroxine (t4) and thyrotropin (tsh) in dried blood spots on filter paper cards have been developed and are used to screen newborn infants for congenital hypothyroidism. blood spot tsh levels are measured in samples for which blood spot t4 levels fall in the lower 10 to 15 percent. there was a low recall rate of approximately one infant in every 550 screened. during a 17-month period 5225 infants have been screened for congenital hypothyroidism ... | 1979 | 290922 |
| the complete maps of bglii, sali and xhoi restriction sites on t4 dc-dna. | t4 dc-dna was digested with the restriction endonucleases bglii, sali and xhoi. overlaps in the three sets of fragments allowed the mapping of all restriction sites relative to each other along the t4 genome. | 1979 | 293460 |
| origins of phage t4 dna replication as revealed by hybridization to cloned genes. | [3h]thymidine-labeled progeny dna was isolated after infection of escherichia coli with two different bacteriophage t4 mutants. these strands were isolated shortly after the initiation of dna replication and hybridized to 15 different (ecori) t4 restriction fragments cloned in plasmid vectors. uniformly labeled t4 [32p]dna extracted from phage particles was cohybridized as a normalizing reference. the results obtained lead to the conclusions that, among the loci tested, initiation occurs predomi ... | 1979 | 293710 |
| breast milk thyroxine and not cow's milk may mitigate and delay the clinical picture of neonatal hypothyroidism. | thyroxine concentration was measured in human milk and cow's milk products by a specific radioimmunoassay. the mean (+/- s.e.m.) milk t4 concentration during the first 5 days postpartum was 0.7 +/- 0.3 microgram/dl (n = 11). the mean t4 concentration between 6-49 days postpartum rose to 3.1 +/- 0.2 microgram/dl (n = 108), falling after 50 days to a mean of 1.4 +/- 0.2 microgram/dl (n = 39). the mean (+/- s.e.m.) t3 concentration in breast milk in the first 50 days postpartum was 386 +/- 17 ng/dl ... | 1979 | 295567 |
| preferential binding of tri-substituted thyronine analogs by bullfrog tadpole tail fin cytosol. | the relative strength of binding of several triiodothyronine (t3) analogs by cytosol prepared from the tail fin of the bullfrog tadpole has been tested and compared with their thyromimetic activity in tail tissue. in competitive binding experiments, four tri-substituted analogs were bound much more strongly than two tetra-derivatives. correlation between binding and relative thyromimetic activity was observed only for three triiodo-substituted compounds, triiodothyronine, its methylene bridge an ... | 1977 | 299742 |
| interaction of thyroid hormones with human muscular tissue, leucocytes and adipose tissue in vitro. | the uptake of triiodothyronine (t3) and thyroxine (t4) by human leucocytes as well as by adipose and muscular tissues in vitro was markedly dependent on the extracellular protein concentration. the presence of extracellular protein was responsible for the difference in the uptake of t3 and t4 by leucocytes (the incorporation of t4 was significantly lower than that of t3), whereas its presence in the medium containing adipocytes did nto influence the incorporation values. in a protein-free medium ... | 1977 | 301819 |
| the effect of exogenous deoxyribonucleosides on thymidine incorporation in t4-infected cells. | 1978 | 305363 | |
| gamma-ray induced double-strand breaks in dna resulting from randomly-inflicted single-strand breaks: temporal local denaturation, a new radiation phenomenon? | the induction of single- and double-strand breaks in dna by gamma-rays has been measured. the maximum number of nucleotide pairs (a) between two independently induced single-strand breaks in opposite strands of the dna which cannot prevent the occurrence of a double-strand break was found to amount to about 16. this value did not differ significantly for the four types of bacteriophage dna investigated (t4, t7 and pm2 dna, and replicative form dna of phage phix174) and was the same in 10(-2) m p ... | 1978 | 305424 |
| lesions of some central nervous structures result in altered pituitary-thyroid response to acute decrease of blood thyroid hormone level. | eight groups (3--6 animals each) of rats weighing 350--400 g were subjected to electrolytic lesions of various parts of habenular, thalamic and hypothalamic areas of brain. on the 6th day after the lesion the level of blood thyroid hormone was acutely decreased with the aid of isovolemic exchange transfusion (iet) of thyroid hormone free blood suspension. the level of thyroxine (t4) in plasma was measured before and during 180 min after iet with the aid of specific radioimmunoassay and the chang ... | 1978 | 305847 |
| effect of thiocyanate and other univalent anions on the binding of thyroxine to rat liver nuclei and homogenate. | the binding of thyroxine (125i-t4) in rat liver homogenate and isolated nuclei was investigated in vitro. in homogenate, the binding of t4 was modified by thiocyanate ion (scn-) added to the incubation mixture as potassium thiocyanate. the displacing effect of scn- increased with increasing concentrations of this compound, the lowest effective dose being that which significantly displaced t4 from liver homogenate (105 pmol per one ml medium). moreover, scn- significantly increased the displacing ... | 1978 | 309388 |
| photodynamic activity of dyes with different dna binding properties ii. t4 phage inactivation. | the photosensitizing efficiency of six dyes--proflavine, 9-aminoacridine, ethidium bromide, thiopyronine, pyronine and acridine red--have been compared on the basis of the inactivation of sensitized t4 phage caused by light irradiation. this reaction was only measurable after diffusion of the dye through the phage capsid and was not observed in the presence of either chloroquine or quinacrine; it followed a single-hit kinetics as a function of the irradiation time. with each dye, a double recipr ... | 1978 | 309450 |
| electro-ejaculation of a complete paraplegic followed by pregnancy. | after having experimented with electro-stimulation on monkeys, the authors have put it into practice with the paraplegic. they report observations on pregnancy of a woman with a complete paraplegic below t4 who was injured 15 years ago. nineteen electro-stimulations and seven artificial inseminations were necessary. the electro-stimulation is easy and can be repeated at will. | 1978 | 310536 |
| cytokinetic studies in children with untreated acute lymphocytic leukaemia (all): relationship to "t" cell markers. | "the labelling index (li), mitotic index (mi) of marrow lymphoblasts and the percent of peripheral blood lymphocytes and lymphoblasts that form rosettes with sheep red cells at 4 degrees c ("t4"), were measured at presentation in 33 children with all. there was a significant correlation between li and mi, but no significant correlations between them and the total white cell count at diagnosis or the "t4" percent. three patients had greater than 55% "t4" rosettes and showed increased li and mi, a ... | 1978 | 311412 |
| changes of lh, tsh, gh, fsh and prl in pituitaries and sera of rats after thyroidectomy and thyroxine treatment as studied by radioimmunoassay and disc electrophoresis. | rat pituitary hormones (lh, tsh, gh, fsh and prl) were located in polyacrylamide gels after the separation of rat pituitary homogenate with the aid of electrophoresis. furthermore, the incorporation of 3h-glucosamine and 14c-leucine into various protein fractions of incubation media and pituitaries incubated for 6 h in vitro, homogenized and then subjected to disc electrophoresis was measured in six groups of rats: 1. control; 2. two weeks after thyroidectomy (tx); 3.--6. two weeks after thyroid ... | 1978 | 311732 |
| predicted secondary structures of four penicillin beta-lactamases and a comparison with two lysozymes. | we have predicted the secondary structures of four beta-lactamases (bacillus cereus, bacillus licheniformis, staphylococcus aureus, and escherichia coli r-tem) by the statistical method of chou & fasman as well as by the information theory method of garnier et al. the secondary structures of all four beta-lactamases are of the alpha/beta type (levitt & chothia's nomenclature), with helices at n- and c-termini. there are about eight short regions each of alpha-helical (30--50%) and beta-strand (1 ... | 1979 | 313376 |
| association of prealbumin deficiency with alpha-1-antitrypsin deficiency. | prealbumin (pa) measurements were made by electrophoretic and radial immunodiffusion techniques in three alpha-1-antitrypsin deficient pi-d) serum samples. the deficiency was characterized as phenotype zz (homozygous). in two out of three serums pa was undetectable, as revealed by the absence of radiothyroxine distribution in the pa area, whereas quantitative estimates of pa by radial immunodiffusion showed very low levels (2--7 mg/100 ml) thus corroborating electrophoretic observations; low pa ... | 1979 | 314560 |
| does a short-term draining of bile duct affect the plasma thyroxine level in rats? | in three groups of male rats weighing about 350 g and fed normal pelleted diet the left femoral artery and vein were cannulated under pentobarbiturate anesthesia and in samples of plasma obtained between 0 and 6 h after the injection of heparin the level of thyroxine (t4) was measured with the aid of specific radioimmunoassay. in addition, in group a (22 animals) and c (17 animals) also the bile duct was cannulated and the total bile was collected into a flask for the same period. in addition, t ... | 1979 | 316765 |
| inhibition of thyroxine-induced metamorphosis by prolactin in tadpoles, rana catesbeiana. | thyroxine (t4)-prolactin interactions on hepatic arginase and ornithine transcarbamylase (otc) as well as hind legs, tail, digestive tract and median eminence were investigated in tadpoles, rana catesbeiana. prolactin completely blocked t4-induced tail resorption, but failed to suppress hind-leg growth, shortening of digestive tract and promotion by t4 of the median eminence development. prolactin blocked t4-induced increase in hepatic arginase activity but not in hepatic otc activity. a possibi ... | 1979 | 316768 |
| [action of 5-hydroxytryptophan on serum thyreostimulin and prolactin in primary hypothyroidism (author's transl)]. | orally 5 htp has significantly decreased serum tsh level in eight patients with primary non treated hypothyroidism, but not in five normal subjects. serum t4 et t3 levels did not change and serum prl did not increase in the two groups. these results indicate a possible inhibitory action of 5 ht on tsh regulation. action of 5 ht on prl has not been defined here. | 1979 | 317634 |
| thyroglobulin biosynthesis in a larval (ammocoete) and adult freshwater lamprey (lampetra planeri bl.). | 1. the biosynthesis of 18-19s thyroglobulin has been studied in a larval and adult freshwater lamprey (lampetra planeri bl.). 2. in vivo and in vitro experiments have been performed by injecting into the coelomic cavity or by incubating branchial region labeled constituents of tg of higher vertebrates (125i, [3h]leucine and various [3h]carbohydrates). 3. larvae (ammocoetes) and adults incorporate all labels into thyroglobulin (18-19s tg), containing a small proportion of labeled t3 and t4, as id ... | 1978 | 318323 |
| translation of bacteriophage t4 mrna into active lysozyme by a wheat germ cell-free system. | 1977 | 319790 | |
| simple isolation method and assay for t4 dna ligase and characterization of the purified enzyme. | a method for the isolation of t4-amber-n82-induced dna ligase is described which results in a nearly homogeneous enzyme preparation after two column chromatographic steps. the enzyme is detected during the purification by its ability to form a stable acid-precipitable enzyme-adenylate complex. some properties of the assay, such as the effect of salt, temperature and incubation time, are presented. the isolated enzyme and its adenylate complex are characterized by acrylamide gel electrophoresis u ... | 1977 | 320008 |
| mutants of escherichia coli "cryptic" for certain periplasmic enzymes: evidence for an alteration of the outer membrane. | mutants in which the expression of periplasmic enzymes by whole cells is reduced (termed "cryptic") are also found to show greatly reduced uptake of labeled adenosine 5'-monophosphate (5'-amp), providing a rapid assay for crypticity. the crypticity of 3'- and 5'-nucleotidase has been examined as a function of substrate concentration. the km for 3'- or 5'-amp increases in the cryptic mutants when whole cells are used as the enzyme source. the vmax is not altered. electrophoretic analysis of prote ... | 1977 | 320175 |
| bacteriophage t4 rna ligase. reaction intermediates and interaction of substrates. | bacteriophage t4 rna ligase catalyzes the atp-dependent ligation of a 5'-phosphoryl-terminated nucleic acid donor to a 3'-hydroxyl-terminated nucleic acid acceptor. we have identified adenylylated dna and rna reaction intermediates in which the amp moiety is attached by a pyrophosphate bond to the 5'-phosphoryl group of the donor. a large amount of dna-adenylate accumulates during the reaction and the dependence of joining and adenylylation on chain length are similar. the adenylylated donor is ... | 1977 | 320212 |
| plasmid replication and hfr formation in strains of escherichia coli carrying seg mutations. | several conditional-lethal mutantions that do not permit the replication of f-factors of escherichia coli k-12 are located at a site called seg. this gene is located on the e. coli chromosome between ser b and thr. it is unrelated to other known genes involved in dna replication. strains carrying seg mutations were unable to replicate f'-lac+, several f'-gal+s, f'-his+ and bacteriophage gamma at 42 degrees. however, neither phage t4, cole1, nor any of the r factors tested were prevented from rep ... | 1977 | 320453 |
| genetic control of mrna decay in t4 phage-infected escherichia coli. | 1977 | 320754 | |
| inhibition of dna-enzyme binding by an rna polymerase inhibitor from t4 phage-infected escherichia coli. | 1977 | 321024 | |
| treatment of functional amenorrhea-galactorrhea with 2-bromoergocryptine. | the present study was undertaken to investigate not only the effectiveness of bromoergocryptine therapy in 13 women with amenorrhea-galactorrhea and hyperprolactinemia without evidence of organic pathology, but also to assess the value of pretreatment evaluation in predicting the response to therapy. sella turcica tomography, base line serum follicle-stimulating hormone, luteinizing hormone (lh), thyroid-stimulating hormone, t4, plasma cortisol levels, and the growth hormone reserve were normal ... | 1977 | 321260 |
| shutoff of host rna synthesis in bacteriophage t4-infected escherichia coli in the absence of host dna degradation and nuclear disruption. | in contrast to its effect on host dna synthesis, nuclear disruption in phage t4-infected escherichia coli b/5 cells has no effect on the shutoff of host rna synthesis. host rna synthesis is shut off normally after infection with t4 multiple mutants that fail to induce both nuclear disruption and host dna degradation. | 1977 | 321802 |
| isolation and characterization of conditional-lethal rho mutants of escherichia coli. | temperature-sensitive nita (rho) mutants of e. coli were isolated; one of them was characterized as an amber mutant. these strains show the nit phenotype (transcription of phage lambda dna independent of the n gene) at low temperatures and are inviable at high temperatures. the mutated sites appear to be between cya and mete on the chromosome. temperature-sensitive nita bacteria not only permit leftward transcription of the lambda genome at a high rate in the absence of the lambda n protein, but ... | 1977 | 322147 |
| atomic coordinates for t4 phage lysozyme. | 1977 | 322662 | |
| [effect of mutation in the polynucleotide ligase gene of t4 phage on recombination and unequal crossing over]. | 1977 | 322973 | |
| metabolic characterization of the viable, residually dividing and nondividing cell classes of recombination-deficient strains of escherichia coli. | the abilities of rec+, recb- recc-, reca-, and reca- recb- rec c- strains to support growth of bacteriophage t4, to take up oxygen, and to maintain cell integrity have been measured. (i) with respect to bacteriophage t4 growth, t4 phage is produced with identical lysis time in single -step growth curves with all strains tested. rec- strains show reduced phage production (fewer infected centers), but the average burst size per infected center is the same for all strains tested. some rec- cells ar ... | 1977 | 323225 |
| adriamycin interactions with t4 dna polymerase. two modes of template-mediated inhibition. | we examined the effect of adriamycin on kinetics of dna synthesis catalyzed by dna polymerase purified from bacteriophage t4-infected escherichia coli. two distinct modes of enzyme inhibition occur: uncompetitive and competitive at "low" and "high" drug:dna nucleotide molar ratios, respectively. competitive inhibition is not observed unless an unblocked amino group is present on the sugar (daunosamine) moiety. a model is proposed to relate the enzyme inhibition kinetics to intercalative and ioni ... | 1977 | 323251 |
| intracellular dna-protein complexes from bacteriophage t4-infected cells isolated by a rapid two-step procedure. characterization and identification of the protein components. | a simple technique has been developed for isolating intracellular dna and its bound proteins from uninfected and phage-infected bacteria. this technique, which utilizes aqueous salt concentrations in the physiological range, is based upon the fact that dna exists in normal cell lysates in a stiff random coil conformation, and has an unusually large excluded volume to mass ratio. such stiff coils display a unique combination of low sedimentation coefficient and large stokes radius, enabling them ... | 1977 | 323253 |
| regulation of deoxyribonucleotide biosynthesis during in vivo bacteriophage t4 dna replication. intrinsic control of synthesis of thymine and 5-hydroxymethylcytosine deoxyribonucleotides at precise ratio found in dna. | the kinetics of the de novo formation of pyrimidine deoxyribonucleotides is the same after infection by wild type bacteriophage t4, which generate very low steady state levels of deoxytibonucleotides, and by t4 dna synthesis-negative mutatants (dna-), which accumulate high levels, suggesting that the control is not by a feedback mechanism. in this study, the ratio of the de novo synthesis of dtmp to hmdcmp derivatives was measured by determining the total thymine and 5-hydroxylxytosine (hmcyt) d ... | 1977 | 323259 |
| regulation of the expression of bacteriophage t4 genes 32 and 43. | 1977 | 324117 | |
| the effect of baseplate mutations on the requirement for tail-fiber binding for irreversible adsorption of bacteriophage t4. | 1977 | 325213 | |
| alteration of the escherichia coli membrane by addition of bacteriophage t4 protein synthesized after infection. | many t4-induced proteins were found associated with the escherichia coli membrane during infection. some of these were apparently ionically bound, but many could be identified as integral parts of the inner and outer bacterial membranes by their selective solubilities in guanidine or sarkosyl. the synthesis and insertion of these proteins into the bacterial membrane were temporally controlled and, once in the membrane, these proteins were stably integrated. host membrane protein synthesis contin ... | 1977 | 325233 |
| effect of salt on the transcription of t7 dna by rna polymerase from t4 phage-infected e.coli. | transcription of t7 dna by t4 core enzyme with host sigma is more sensitive to kci than that by host core enzyme with host sigma. when salt is added after initiation of rna chains has occurred, it is not inhibitory. salt affects the binding of t4 enzyme to t7 dna to the same degree as the binding of host enzyme. active preinitiation complex formation is inhibited more by salt with the t4 enzyme and the inhibition is temperature-dependent. | 1977 | 325528 |
| a temperature-sensitive riib mutation which affects the synthesis of bacteriophage t4 riib protein. | 1977 | 325880 | |
| study of the transfer rnas coded by t2, t4, and t6 bacteriophages. | t2, t4, and t6 bacteriophage trnas coding for arginine, leucine, proline, isoleucine, and glycine were isolated under conditions of short term and long term infection of escherichia coli b cells. the corresponding phage trna species were examined for sequence homology by rna-dna hybridization analysis and by their relative behavior on reversed phase chromatography. the results indicate that all three t-even phages code for similar trna species; however, some trna species are homologous, others a ... | 1977 | 326783 |
| multiple interactions of a dna-binding protein in vivo. ii. effects of host mutations on dna replication of phage t4 gene 32 mutants. | 1977 | 327075 | |
| the use of bacteriophages as indicators in host-mediated assays. longevity of phages lambda, t4 and kappa in the blood-stream of mice. | 1977 | 327317 | |
| proteolysis during t4 head maturation: evidence against the involvement of a phage-induced trypsin-like enzyme. | 1977 | 327685 | |
| inhibition of beta-galactosidase synthesis in escherichia coli after infection with different dna and rna phages. | infection of escherichia cooi with t1, t2r+, t3 and t4 phages leads to an immediate inhibition of beta-galactosidase synthesis. similar results were obtained with the virulent mutant of phage lambda. the degree of inhibition of beta-galactosidase synthesis depends on the time delay between the addition of the inducer and the phage particles, and on the amount of phage dna, which has penetrated into the host cell. rna phage ms2 exhibited no inhibitory effect on enzyme synthesis. | 1977 | 328356 |
| further studies on bacteriophage t4 dna synthesis in sucrose-plasmolyzed cells. | this paper describes several technical improvements in the sucrose-plasmolyzed cell system used in earlier experiments on dna synthesis in situ with escherichia coli infected by dna-defective mutants of bacteriophage t4 (w. l. collinsworth and c. k. mathews, j. virol. 13:908-915, 1974). using this system, which is based primarily on that of m. g. wovcha et al. (proc. natl. acad. sci. u.s.a. 70:2196-2200, 1973), we reinvestigated the properties of mutants bearing lesions in genes 1, 41, and 62, a ... | 1977 | 328926 |
| bacteria with defective rho factors suppress the effects of n mutations in bacteriophage lambda. | a prediction based on the model for n-gene function of bacteriophage lambda proposed by roberts (1971) is confirmed by showing that a lambdan- double mutant is able to grow in strains of e. coli with defective rho transcription termination factors. the burst sizes for lambdan- in these strains range from 5 to 24% the burst sizes for lambdan+ in the same strain. this low level of suppression is also evident in the levels of synthesis of the lambda exonuclease and is consistent with other evidence ... | 1977 | 329106 |
| water-to-air transfer of virus. | bubbles rising through suspensions of the bacteriophages t2 and t4 and of escherichia coli adsorb and eject these particles in droplets that are formed when the bubbles burst. the concentration of the viruses in ejected droplets, determined from electron microscopy, exceeded the suspension concentration by 50 times. similar results were obtained for escherichia coli. the viability of some of the adsorbed particles was established by biological counts. | 1977 | 329413 |
| effects of pyrrol-carboxylic acid derivatives on the growth of coliphages. | effects of 14 pyrrol-carboxylic acid derivatives and analogues (py-compounds) on the growth of coliphage ms2 using e. coli e102 (hfr) as the host were measured by the agar double-layer method. enlargements of plaque size were observed with 7 py-compounds but increase in plaque numbers was not induced. these enlargements of plaque size were specific to rna coliphages ms2, ga and qbeta and not found with dna coliphages delta ac and t4. furthermore, the interaction between py-compound py-10 and the ... | 1977 | 330014 |
| [mutation of bacteriophage t4 restoring phage supressor psul+ activity in bacterial strain escherichia coli bn]. | the mutant of bacteriophage t4psu1+xf2 carrying a mutational aleration in the central region of proline-serine trna precursor is isolated. the mutational alteration results in the recovery of amber suppressor activity of phage psu1+ serine trna in escherichia coli bn in which the synthesis of this trna is normally blocked. since the amber suppressor activity of mutant serine trna becomes sensitive to a restrictive action of strr mutations, its structure seems to be different from that of parenta ... | 1977 | 330314 |
| [recombination of amber mutants of bacteriophage t4b. ii. localization of amber mutants on maps of genes 30, 34, 35, 36 and 38]. | localization of 275 amber mutants of five genes of phage t4b (30, 34, 35, 36 and 38) on genetic maps allowed us to determine the recombination length of these genes. gene 34 substantially differs from the rest studied genes by numbers of amber mutants isolated in each gene and by recombination frequency. in particular, according to the results of crossing the flank markers, the recombination length of gene 34 is 10 times greater than in gene 38; using the summary value of recombination frequenci ... | 1977 | 330318 |
| [effect of amino acid substitutions in the polypeptide chain of dna-polymerase on manifestation of the mutator effect]. | thin map of gene 43, controlling the synthesis of t4 dna polymerase, is obtained by mapping experiments performed with 39 amber mutants, and is used for analysis of the sites of dna polymerase gene from the point of view of displaying the mutator effect. the mutant sites studied possessed different reaction on amino acid substitutions in the polypeptide chain of the enzyme. most of sites of the dna polymerase gene, with the exception of two "supersensitive", responsed only on the apparent type o ... | 1977 | 330319 |
| inhibitory effect of agents altering the structure of dna on the synthesis of pyrimidine deoxyribonucleotides in bacteriophage t4 dna replication. | 1977 | 330522 | |
| micrococcus luteus correndonucleases. ii. mechanism of action of two endonucleases specific for dna containing pyrimidine dimers. | py pyrimidine dimers py correndonucleases i and ii from micrococcus luteus act exclusively on thymine-thymine, cytosine-cytosine, and thymine-cytosine cyclobutyl dimers in dna, catalyzing incision 5' to the damage and generating 3'-hydroxyl and 5'-phosphoryl termini. both enzymes initiate excision of pyrimidine dimers in vitro by correxonucleases and dna polymerase i. the respective incised dnas, however, differ in their ability to act as substrate for phage t4 polynucleotide ligase or bacterial ... | 1977 | 330526 |
| analysis of the structure of t4 bacteriophage-modified valyl-trna synthetase by limited proteolysis and isoelectric focusing. | the new form of valyl-trna synthetase (ec 6.1.1.9) that appears immediately after infection of escherichia coli with bacteriophage t4 was purified and subjected to mild proteolysis using five different proteases. the inactivation of aminoacylation activity was both more extensive and rapid than that obtained with valyl-trna synthetase purified from uninfected e. coli. the addition of bulk trna from e. coli b protected the phage-specific form of valyl-trna synthetase from proteolysis, but atp and ... | 1977 | 330535 |
| bacteriophage t4 virion dihydrofolate reductase: approaches to quantitation and assessment of function. | this paper is concerned with the physiological role(s) of t4 phage-coded dihydrofolate reductase, which functions both in dna precursor metabolism and as a virion protein. (i) we have detected enzyme activity in noninfectious particles produced under restrictive conditions by gene 11 mutants. this supports the conclusion of kozloff et al. (j. virol. 16:1401-1408, 1975) that the protein lies in the baseplate, covered by the gene 11 protein. (ii) we have obtained further evidence for virion dihydr ... | 1977 | 330880 |
| conditional lethal mutants of bacteriophage t4 unable to grow on a streptomycin resistant mutant of escherichia coli. | sixteen conditional lethal mutants of bacteriophage t4d have been isolated which grow on escherichia coli cr63 (a su+ streptomycin-sensitive k12 strain) but are restricted by cr/s (a streptomycin-resistant derivative of cr63). these mutants have been given the prefix str. four of these mutants are amber and 12 appear to be missense. eleven of the 12 missense mutants appear to be "pseudo-amber" (i.e. they are restricted by a su- e. coli b strain but not by a su- k12 strain); the other missense mu ... | 1977 | 331100 |
| t4 phage-coded deoxycytidylate hydroxymethylase: purification and studies on intermolecular interactions. | 1977 | 332172 | |
| [in vivo and in vitro studies of phage t4 lysozyme mrna translation]. | translation of phage t4 lysozyme mrna is studied in vivo and in vitro. polyribosomes, carrying growing lysozyme polypeptides, are found to be homogenous enough and to contain 6 ribosomes. complete molecules of phage lysozyme, which possess an enzymatic activity and are similar to the native enzyme in its electrophoretic mobility in polyacrylamide gel, have been synthetized in vitro on rna isolated from phage-infected cells. the efficiency of rna translation in cell-free system is discussed on th ... | 1977 | 332238 |
| bacteriophage t4 rna ligase: preparation of a physically homogeneous, nuclease-free enzyme from hyperproducing infected cells. | infection of escherichia coli by a bacteriophage t4 rega, gene 44 double mutant leads to about a 7-fold increase in the amount of rna ligase obtained after infection by wild-type phage. using cells infected by the double mutant, rna ligase was purified to homogeneity with a 20% yield. unlike previous preparations of this enzyme, the ligase is free of contaminating nuclease and is therefore suitable for intermolecular ligation of dna substrates. in the course of these studies it was discovered th ... | 1977 | 333400 |
| bacteriophage t4 rna ligase is gene 63 product, the protein that promotes tail fiber attachment to the baseplate. | rna ligase and tail fiber attachment activities, normally induced following bacteriophage t4 infection of escherichia coli, are not induced when gene 63 amber mutants of t4 infect nonpermissive host cells. both activities are induced when these mutants infect permissive hosts, or when revertants of these mutants infect nonpermissive hosts. when one of these mutants infects a host that carries supf, both activities are more than normally heat labile. rna ligase, purified to homogeneity, promotes ... | 1977 | 333436 |
| biochemical mechanism of uracil uptake regulation in escherichia coli b. allosteric effects on uracil phosphoribosyltransferase under stringent conditions. | the regulation of uracil uptake in bacteria was studied in bacteriophage t4-infected cells, where host-specific, stable rna synthesis is completely shut-off by phage, and where phage-specific rna synthesis, which is not stringently regulated, could be followed by a continuous incorporation of uracil. this incorporation into phage rna was found to be dependent on the allelic state of the rel gene and it was thus severely restricted under stringent conditions. this was not the case with adenine, w ... | 1977 | 334763 |
| [regulation of anti-late rna synthesis in bacteriophage t4: a delayed early control]. | 1977 | 335074 | |
| repair of pyrimidine dimers in radiation-sensitive mutants rad3, rad4, rad6 and rad9 of saccharomyces cerevisiae. | the ability to remove ultraviolet (uv)-induced pyrimidine dimers was examined in four radiation-sensitive mutants of saccharomyces cerevisiae. the susceptibility of dna from irradiated cells to nicking by either the t4 uv-endonuclease or an endonuclease activity found in crude extracts of micrococcus luteus was used to measure the presence of dimers in dna. the rad3 and rad4 mutants are shown to be defective in dimer excision whereas the rad6 and rad9 mutants are proficient in dimer excision. | 1977 | 335235 |
| endonucleolytic cleavage of parental dna and t4 late-gene expression: distribution analysis of single-strand and double-strand breaks. | in order to investigate the dependency of late transcription on concurrent dna replication during bacteriophage t4 development, we analyzed the endonucleolytic cleavage kinetics of the dna of a t4 mutant lacking dna polymerase, dna ligase and exonuclease by using the sucrose gradient sedimentation technique. our results can be summarized as follows. 1. the single-strand endonucleolytic cleavage of the t4 mutant dna is not a random process. 2. the number of single-strand nicks reaches a plateau l ... | 1977 | 336368 |
| purification and some novel properties of escherichia coli rnase ii. | rnase ii of escherichia coli (ec 3.1.4.23) has been purified to apparent homogeneity. the k+-activated diesterase activity against poly(u), which defines rnase ii, cochromatographs with activity against t4 mrna or pulse-labeled e. coli rna successively on deae-cellulose, hydroxyapatite or phosphocellulose, and sephadex g-150 columns. activities with both substrates are selectively reduced to less than 2% of the wild type level in a newly isolated mutant strain, s296, or after thermal inactivatio ... | 1977 | 336625 |
| stimulation of cell division by t4 infection in escherichia coli dnaets at nonpermissive temperature. | filamentous cells resulting from growth of a dnaets mutant of escherichia coli at high temperature were stimulated to divide by infection with bacteriophage t4. the effect appears to be related to t4 dna synthesis; no increase in cell number took place in chloramphenicol-treated. t4-infected cells nor in cells infected with dna synthesis-less mutants of t4. the ability of cells to divide after t4 infection was dependent on the length of time that the cells had been grown at 42 degrees c, indicat ... | 1977 | 337113 |
| regulation of the intracellular concentration of t4 induced trna. | we have studied the biosynthesis of t4 induced trna's upon infection of e. coli be cells in low phosphate (l.p.) medium (10(-4) m po---4). under out experimental conditions the onset of phage dna synthesis occurs about 15 min after infection, while the first intracellular phage appears one hour later. amounts of newly synthesized dna and phage burst size are equivalent to the values obtained in standard (m9) medium (10(-1) m po---4). we present evidence that the synthesis of mature trna's and of ... | 1977 | 337117 |
| [agglutinin-like behavior of human haptoglobins toward streptococci with the t4-antigen]. | 1977 | 337163 | |
| the "patchy" immunodeficiency of cba/n mice. | the in vivo responses of cba/n (which have an x-linked defect of b lymphocyte differentiation) and cba/j normal mice to 2,4,6-trinitrophenylated (tnp) bacteriophage t4 and diplococcus pneumoniae cs variant have been compared. both antigens are thymus-independent (ti), and tnp-cs additionally contains the phosphorylcholine (pc) epitope, cba/n and cba/j mice give tnp plaque-forming cell responses similar in magnitude and avidity although only cba/j give a pc response when challenged with tnp-cs. t ... | 1977 | 338312 |
| purification and properties of deoxythymidine kinase induced by bacteriophage t4 infection. | 1977 | 338602 | |
| processivity of dna exonucleases. | a homopolymer system has been developed to examine the digestion strategies of dna exonucleases. escherichia coli exonuclease i and lambda-exonuclease, are processive enzymes. however, t7 exonuclease, spleen exonuclease, e. coli exonuclease iii, the 3' leads to 5'-exonuclease of t4 dna polymerase, and both the 3' leads to 5' and the 5' leads to 3' activity of e. coli dna polymerase i dissociate frequently from the substrate during the course of digestion. regions of duplex dna are a dissociation ... | 1978 | 338608 |
| [results of using dibunol in bladder tumors]. | intravesical instillations of 10% dibunol liniment were used for the treatment of 132 patients with bladder tumors. an objective improvement was noted in 62.4%, including considerable lessening of the tumor size in 20% and its disappearance in 8.8% of patients. an efficacy of the treatment was considerably greater in bladder cancer in stages t1--t2 than in stages t3 and t4. the frequency of bladder cancer recurrence is found to be lowered following surgery associated with application of dibunol, ... | 1977 | 339536 |
| mccune-albright syndrome in a male child: a clinical and endocrinologic enigma. | a 6 5/12-year-old boy with polyostotic fibrous dysplasia, café-au-lait pigmentation of the skin, and precocious pubertal development was studied for two years. parathormone, calcium, phosphorus, testosterone, cortisol, and growth hormone levels were within normal limits. urinary 17-ketosteroids, 17-ketogenic steroids, and estrogens were at the upper limits of normal. after gnrh stimulation, there was only a very slight increase in lh and no increase in fsh. there was no increase in tsh after trh ... | 1978 | 340627 |
| relationship between haptoglobin and streptococcus pyogenes t4 antigens. | 1978 | 340961 | |
| phenotypic correction of nonsense mutation carrying non-converting pe5 phages in shigella flexneri with suppressor gene. | (i) phenotypic suppression by aminoglycoside antibiotics of a polyauxotrophic shigella flexneri var. y strain on partially completed minimal medium has shown that its thr dependence is associated with nonsense mutation. induced thr+ revertants selected from the culture yielded clones correcting the lytic cycle of nonsense t4 mutant phages. transfer of r1am plasmid to these clones carrying a nonsense mutation of ampicillin resistance was performed. in this manner a s. flexneri var. y derivative w ... | 1977 | 341654 |
| drug therapy reviews: management of hypothyroidism. | the therapeutic management of hypothyroidism caused by deficient thyroid hormone production is discussed. the therapeutic use of the following thyroid agents is reviewed: levothyroxine sodium, thyroid usp, thyroglobulin, liotrix, and liothyronine sodium. myxedema coma, neonatal hypothyroidism, primary hypothyroidism, and secondary and tertiary hypothyroidism are specific hypothyroid states for which drug therapy is discussed. levothyroxine sodium is the preferred agent because of consistent pote ... | 1978 | 341699 |
| streptococcal impetigo and acute glomerulonephritis in children in cairo. | impetigo contagiosa in cairo affected young children of both sexes, the face being the main site. post-impetigo nephritis, confirmed by a low serum c3 level and by urinalysis, occurred in only 11% of cases. streptococcus pyogenes strains were recovered from 84% of the skin lesions. sixteen types were identified according to their t-protein, and most infections were associated with t3/b3264, t13/b3264, t5, t11, t12, t8/25/imp 19 and t14/49; the majority of these types were also recovered from hou ... | 1978 | 341956 |
| [allele specificity of genetic recombination in t4 phage using the indicator crossing study method]. | the diagrams of relative correction ability of eighteen rii mutants of t4 phage were constructed on the basis of two-factor crosses, which were grouped into indicator series. in each series a pair of closely linked compared markers was crossed against indicator ones, the latter being distant enough so as to avoid simultaneous correction with the compared marker. the differences between the frequencies of wild type recombinants in crosses of two compared markers with indicator ones remained const ... | 1978 | 342334 |
| [radiobiological method of studying the structure of the partially diploid area in t4 bacteriophage]. | the mechanism of cross-reactivation after uv-irradiation was examined using different deletion mutants as recipients. a model of the rescue mechanism of partly diploid area was suggested. the method of cross-reactivation in demonstrated to permit an easy determination of the orientation of duplicated genes. | 1978 | 342335 |
| differential effect of hydroxyurea on a ribonucleotide reductase system. | infection of escherichia coli with phage t4 induces a large increase in ribonucleotide reductase activity. we show that hydroxyurea inhibits t4-induced cdp, adp, udp, and gdp reductase activities in vitro. moreover, there are significant differences in the degree of inhibition of each ribonucleotide reductase activity. the reductase activities for cdp and adp are more sensitive to hydroxyurea than those for udp and gdp, particularly at high hydroxyurea molarities. as little as 5 x 10(-4)m hydrox ... | 1978 | 342523 |
| late effect of bacteriophage t4d on the permeability barrier of escherichia coli. | cold centrifugation of lysis-inhibited escherichia coli b infected with wild-type t4d results in extensive lysis beginning around 20 min after infection at 37 degrees c. infection with an e mutant, which fails to make lysozyme, prevents lysis, but does not prevent a marked loss of k+ and mg3+. the t gene product, thought to disrupt the cytoplasmic membrane in natural lysis, is not required for this handling-induced cation loss or lysis. three lines of evidence argue that late protein synthesis i ... | 1978 | 342725 |
| isolation of labeled triiodothyronine from serum using affinity chromatography: application to the extimation of the peripheral t4 to t3 conversion in rats. | a method for the isolation of small quantities of labeled 3,5,3' -triiodothyronine (t3) from serum or thyroid extracts is described. conjugates of rabbit anti-t3 antibody to sepharose 4b are incubated with 0.5 to 1 ml of human or rat serum at ph 8.6 for 1 hr. the tubes are centrifuged and washed with buffer followed by 6 m guanidine to remove nonspecifically bound labeled thyroxine (t4). the fraction of t3 and t4 bound to the sepharose conjugate varies depending on the concentration of serum in ... | 1978 | 342873 |
| in vivo synthesis and properties of uracil-containing dna. | t4 bacteriophage dna containing as much as 30% of its thymine replaced by uracil can be synthesised in escherichia coli deficient in both dutpase and uracil--dna glycosidase. this uracil-containing dna is competent for rna transcription, and can be packaged into phage which are viable, if the host cells are deficient in uracil--dna glycosidase activity. if the host cells are not deficient in this glycosidase activity the infecting phage dna is rapidly attacked, resulting in more than 50% acid-so ... | 1978 | 342978 |
| identification of a host protein necessary for bacteriophage morphogenesis (the groe gene product). | mutations in the groe gene of escherichia coli, which block the correct assembly of the phage lambda head, have been previously described. many groe mutations exert pleiotropic effects, such as inability to propagate phages t4 and t5 and inability to form colonies at 43 degrees. with the help of the ecori and hindiii restrictionenzymes and the appropriate phage vectors, we have constructed two lambda transducing phages, called w3 and h18, that carry the groe+ bacterial gene. upon lysogenization ... | 1978 | 343101 |
| role of the host in virus assembly: cloning of the escherichia coli groe gene and identification of its protein product. | correct assembly of the heads of bacteriophages lambda and t4 requires the function of the groe gene of the escherichia coli host. we have isolated a transducing derivative of lambda, called lambda gt-ec.groe, that carries a functional copy of the groe gene. unlike wild-type lambda, this phage is able to form plaques on hosts with a mutant groe gene. we have isolated an amber mutation in the groe gene carried by the phage, and this has made it possible to identify the groe product as a protein o ... | 1978 | 343102 |
| attachment of tail fibers in bacteriophage t4 assembly. purification, properties, and site of action of the accessory protein coded by gene 63. | 1978 | 344316 | |
| construction and properties of recombinant plasmids containing the rii genes of bacteriophage t4. | the ecori digestion products of phage t4 dna have been examined using a phage dna transformation assay. a 2.6 x 10(6) dalton fragment was found to contain the rii genes. this fragment was purified and then treated with hindiii endonuclease. the cleavage products were ligated to the vector plasmid pbr313 and viable recombinant plasmids recovered. a genetic assay was employed to demonstrate that the recombinants contained t4 dna and to localize on the phage genetic map the ecori and hindiii sites ... | 1978 | 345100 |
| thyroid function tests in patients on long-term treatment with various anticonvulsant drugs. | thyroid function tests were studied in patients undergoing long-term treatment with various anticonvulsant drugs. previous reports that diphenylhydantoin induces a decrease in the serum concentrations of total and free thyroxine (t4) and triiodothyronine (t3) without a change in the tsh concentration were confirmed. diphenylhydantoin had no effect on reverse t3. carbamazepine was also found to decrease serum t4, the free t4 index and t3 but, with the exception of t3, the decrease was smaller tha ... | 1978 | 346267 |
| dna breakage, repair, and lethality accompanying 125i decay in microorganisms. | effects of 125i decay in dna were investigated by measurements of strand breaks and lethal efficiencies of the decays. in bacteriophages t1 and t4, local decay effects were compared with effects of the emitted electrons by induction of both single (ssb) and double strand breaks (dsb) in the intact phage head and in extended free state dna. most dsbs were found to result from local decay effects whereas most real ssbs are caused by the electrons. a simple one-to-one relationship seems to exist in ... | 1978 | 346313 |
| nutritionally-induced alterations in thyroid hormone metabolism and thermogenesis. | serum 3,5,3'-triiodothyronine (t3) is increased by overnutrition and decreased by starvation. the production rate of t3 was increased by overfeeding (82%), but t4 production did not change. feeding a weight maintenance diet with high cho mimiced serum t3 and rt3 changes of overfeeding, substitution of cho by fat those of starvation. vo2 increased during overfeeding and in t4 equilibrated volunteers supplemented with 40 microgram t3 daily for 2 weeks. no weight change occurred in the latter subje ... | 1978 | 348487 |
| functional compartmentation of dna precursors in t4 phage-infected bacteria. | 1978 | 348692 | |
| use of the t4 polynucleotide ligase in the joining of flush-ended dna segments generated by restriction endonucleases. | double-stranded dna segments with completely base-paired ends were obtained by the action of various restriction endonucleases on phage and plasmid dnas. these segments were joined covalently by the t4 polynucleotide ligase. the joining was monitored by the electron microscopy count of intramolecularly circularized segments. the highest extent of joining, close to 75%, was observed at 15-25 degrees c with the segments resulting from the action of the bacillus subtilis (strain r) restriction endo ... | 1978 | 350585 |
| [transmission of bacteriophage t4 amber mutants. i. temperature sensitivity of gene 26 t4 phage mutant amn131 multiplication in escherichia coli b cells]. | when studying the single cycle of the multiplication of gene 26 mutant amn131 of phage t4, like in temperature shift experiments, the yield of this mutant in non-permissive host depends greatly on the temperature. the burts size of phage in escherichia coli b is found to be 3.3 phage particles at 25 degrees c, 1.6 at 30 degrees c, 0.051 at 37 degrees c and 0.0007 at 41 degrees c. in the case of permissive host (e. coli cr-63) the burst size per cell decreases from 158 to 49 phage particles at th ... | 1978 | 350706 |
| escherichia coli k-12 mutants deficient in uracil-dna glycosylase. | a new assay specific for uracil-dna glycosylase is described, escherichia coli mutants partially and totally deficient in uracil-dna glycosylase activity have been isolated by using this assay in mass-screening procedures. these have been designated ung mutants. the ung gene maps between tyra and nadb on the e. coli chromosome. t4 phage containing uracil in their dna grow on the most glycosylase-deficient hosts but are unable to grow on wild-type bacteria. this provides a simple spot test for th ... | 1978 | 350837 |