| cntf rescues motoneurons from ontogenetic cell death in-vivo, but not in-vitro. | we studied the effect of cntf (ciliary neurotrophic factor, human recombinant and chick) on the survival of motoneurons in the embryonic chick lumbar spinal cord during the period of ontogenetic cell death. daily applications of 5 micrograms cntf to the chorionic-allantoic membrane from embryonic day 6 (e6) to e9 maintained approximately 15,500 motoneurons as opposed to 13,200 in controls. in contrast, cntf failed to promote the survival of cells in spinal cord cultures enriched for motoneurons. ... | 1990 | 2129881 |
| primary structure and functional expression from complementary dna of a human interleukin-1 receptor antagonist. | human monocytes induced with adherent igg secrete an interleukin-1 receptor antagonist which could be important for the in vivo regulation of il-1 activity. a complementary dna for this molecule has been isolated from a human monocyte library. analysis of monocyte rna indicates that the gene is transcriptionally regulated. the sequence of the receptor antagonist indicates that it is structurally similar to il-1 beta. expression of the cdna in escherichia coli yields il-1 receptor antagonist acti ... | 1990 | 2137201 |
| effects of bacterial lipopolysaccharide and calmodulin on ca2(+)-atpase and calcium in human natural killer cells, studied by a combined technique of immunoelectron microscopy and ultracytochemistry. | our previous studies indicate that bacterial lipopolysaccharide (lps) enhances natural killer (nk) cell-mediated cytotoxicity and increases intracellular calcium (ca2+) in hepatocytes. calmodulin (cam) regulates ca2(+)-atpase activity, intracellular ca2+, and is also implicated in nk cell-mediated cytolysis. in the present work, the effects of lps and cam on ca2(+)-atpase and intracellular ca2+ in human nk cells were studied by a combined technique of immunogold electron microscopy and ultracyto ... | 1990 | 2137483 |
| human bisphosphoglycerate mutase expressed in e coli: purification, characterization and structure studies. | bisphosphoglycerate mutase (ec 5.4.2.4.) is an erythrocyte-specific enzyme whose main function is to synthesize 2,3-diphosphoglycerate (glycerate-2,3-p2) an effector of the delivery of o2 in the tissues. in addition to its main synthase activity the enzyme displays phosphatase and mutase activities both involving 2,3-diphosphoglycerate in their reaction. using a prokaryotic expression system, we have developed a recombinant system producing human bisphosphoglycerate mutase in e coli. the express ... | 1990 | 2145041 |
| a new assay for o6-alkylguanine-dna-alkyltransferase to determine dna repair capacities using lambda-phage dna as substrate. | one o6-methylguanine (o6-meg) was introduced into each bamhi site of lambda-phage dna as a substrate for the determination of the dna repair protein o6-alkylguanine-dna-alkyltransferase. a new assay using as the detection group 32p-labeled phosphate introduced at the 3' position of the modified nucleoside by incorporation of 32p-labeled ttp in the 3'-neighboring position proved highly sensitive: 10(-16) mol of the dna lesion was still easily detectable. this dna, which has greater than 1000 bp r ... | 1990 | 2145087 |
| characterization of thrombin- and plasmin-resistant mutants of recombinant human single chain urokinase-type plasminogen activator. | recombinant human single-chain urokinase-type plasminogen activator (suc-pa) (sm0: wild type) and its variants resistant to plasmin and/or thrombin (sm1: lys135 to gln; sm3: phe157 to asp; and sm4: lys135 to gln and phe157 to asp) have been constructed by site-directed mutagenesis with the aim of producing more efficient thrombolytic agents [miyake, t. et al. (1988) j. biochem. 104, 643-647]. in the present study, we characterized the recombinant variant scu-pas expressed in escherichia coli. th ... | 1990 | 2146258 |
| a new approach to optimal antibiotic dosage regimen by coupling pharmacokinetics and killing curve parameters. | antibiotic therapy is directed against bacteria responsible for infectious pathology which are able to resist treatment mainly when the dosage is misadapted. the choice of the initial dosage regimen actually takes into account toxicological, bacteriological and pharmacokinetic parameters. the determination of the classical bacteriological data is performed in vitro using fixed drug concentrations that are far from human therapy conditions, and moreover the efficiency is not well defined. the est ... | 1990 | 2146452 |
| de novo purine nucleotide biosynthesis: cloning of human and avian cdnas encoding the trifunctional glycinamide ribonucleotide synthetase-aminoimidazole ribonucleotide synthetase-glycinamide ribonucleotide transformylase by functional complementation in e. coli. | the trifunctional enzyme encoding glycinamide ribonucleotide synthetase (gars)-aminoimidazole ribonucleotide synthetase (airs)-glycinamide ribonucleotide transformylase (gart) was cloned by functional complementation of an e. coli mutant using an avian liver cdna expression library. in e. coli, genes encoding these separate activities (purd, purm, and purn, respectively) produce three proteins. the avian cdna, in contrast, encodes a single polypeptide with all three enzyme activities. using the ... | 1990 | 2147474 |
| induction of an interleukin-1 receptor (il-1r) on monocytic cells. evidence that the receptor is not encoded by a t cell-type il-1r mrna. | primary human monocytes and the human monocytic cell line thp-1 were induced to express receptors for interleukin-1 alpha (il-1 alpha) and il-1 beta. treatment of primary monocytes with dexamethasone resulted in a 10-fold increase in receptor number over untreated cells, to approximately 2,000 receptors/cell. treatment of thp-1 cells with phorbol ester followed by prostaglandin e2 and dexamethasone resulted in the expression of approximately 30,000 receptors/cell. competitive binding assays on t ... | 1990 | 2148319 |
| construction, expression and unexpected regulatory properties of a tropomyosin mutant with a 31-residue deletion at the c-terminus (exon 9). | the cdna coding for human skeletal muscle beta-tropomyosin was expressed in escherichia coli to produce an unacetylated beta-tropomyosin. this cdna was deleted from the sequence corresponding to the exon 9 and expressed in e. coli to produce an unacetylated beta-tropomyosin mutant lacking the c-terminal residues 254-284. the main structural and functional properties of the two isolated proteins, designated tropomyosin-1 and des-(254-284)-tropomyosin, respectively, were characterized in compariso ... | 1990 | 2148519 |
| human synexin (annexin vii) polymorphisms: tissue specificity and expression in escherichia coli. | | 1990 | 2150946 |
| localization and characterization of three different beta-adrenergic receptors expressed in escherichia coli. | after fusion with the n-proximal portion of the outer membrane protein lamb, three beta-adrenergic receptors, the human beta 1- and beta 2- and turkey beta 1-adrenergic receptor, were expressed in escherichia coli with retention of their own specific pharmacological properties. molecular characterization and localization of the three receptors in bacteria and comparison of the behaviour of each hybrid protein are reported. the bacteria were lysed and fractionated on a sucrose gradient. saturable ... | 1990 | 2153543 |
| release of iron from phagocytosed escherichia coli and uptake by neutrophil lactoferrin. | escherichia coli were labeled with 59fe and then either treated with myeloperoxidase, h2o2, and chloride or opsonized and mixed with human neutrophils. the myeloperoxidase system at ph 7.4 caused release of most of the bacterial 59fe. a similar result has been obtained by rosen and klebanoff (j biol chem 257:13731, 1982) but at ph 5. iron release at ph 7.4 did not require the presence of a chelator, and the majority passed through a 10,000 relative molecular mass cut-off ultrafiltration membrane ... | 1990 | 2154270 |
| cloning and sequence analyses of cdnas for interferon- and virus-induced human mx proteins reveal that they contain putative guanine nucleotide-binding sites: functional study of the corresponding gene promoter. | the human protein p78 is induced and accumulated in cells treated with type i interferon or with some viruses. it is the human homolog of the mouse mx protein involved in resistance to influenza virus. a full-length cdna clone encoding the human p78 protein was cloned and sequenced. it contained an open reading frame of 662 amino acids, corresponding to a polypeptide with a predicted molecular weight of 75,500, in good agreement with the mr of 78,000 determined on sodium dodecyl sulfate gels for ... | 1990 | 2154602 |
| cloning and expression of a protein-tyrosine-phosphatase. | a rat brain cdna library was screened by using a mixture of oligonucleotides whose sequences were deduced from the amino acid sequence of a human placental protein-tyrosine-phosphatase (ptpase; ec 3.1.3.48) reported by charbonneau et al. [charbonneau, h., tonks, n. k., walsh, k. a. & fischer, e. h. (1988) proc. natl. acad. sci. usa 85, 7182-7186]. the isolated clones encode a ptpase of 432 amino acids having a mass of 49,679 daltons and showing 97% sequence identity to the corresponding 321 resi ... | 1990 | 2154749 |
| construction of expression plasmids for the fusion protein of sendai virus, and their expression in e. coli cells and eucaryotic cells. | to examine the properties and the role of the fusion protein (f) of sendai virus at the molecular level, a plasmid, puc-f, was constructed by inserting cdna for the f protein into a puc vector. upon induction of e. coli cells transformed with puc-f, a new protein was obtained, which was identified as fo on western blot analysis. the cdna fragment for the f gene was excised from puc-f and inserted into an eucaryotic expression vector, psvl, to yield psvl-f. cos-1 cells transfected with psvl-f gav ... | 1990 | 2156733 |
| human dna topoisomerase ii: evaluation of enzyme activity in normal and neoplastic tissues. | we have used both a quantitative filter binding assay and a decatenation assay to measure dna topoisomerase ii activity. the filter binding assay, which measures catenating activity, is able to detect topoisomerase ii activity at 50-100-fold lower protein concentrations than the decatenation assay. because of this remarkable sensitivity, we have been able to quantitate topoisomerase ii activity in a variety of normal and neoplastic human tissues. the highest level of enzyme activity in normal ti ... | 1990 | 2158345 |
| in vitro transcriptional activation, dimerization, and dna-binding specificity of the epstein-barr virus zta protein. | the epstein-barr virus bzlf1 immediate-early gene encodes a transcriptional activator protein, zta, which acts as a key regulatory switch in the transition between the latent and lytic viral life cycle. in this work, full-length zta was expressed at high levels in escherichia coli and purified to homogeneity by dna affinity chromatography. the bacterial protein bound to specific target sequences (zta response elements) and activated transcription in vitro from an epstein-barr virus early target ... | 1990 | 2159531 |
| inhibition of specific binding of ebna 1 to dna by murine monoclonal and certain human polyclonal antibodies. | ebna 1 was expressed as a nonfusion protein in escherichia coli under control of the lac promoter. the major immunoreactive ebna 1 proteins migrated as two doublets with molecular masses of about 39/41 and 49/51 kda. gel mobility shift experiments showed that these products exhibit the sequence-specific dna binding on ori p previously characterized for a 28-kda lambda n-fusion protein encompassing the carboxy third of the ebna 1 protein. three monoclonal antibodies previously found to react with ... | 1990 | 2161154 |
| subclass distribution of antigen-specific iga antibodies in normal donors and individuals with homozygous c alpha 1 or c alpha 2 gene deletions. | to analyze the subclass restriction of ag-specific iga, sera and saliva from healthy blood donors and from iga class or subclass deficient individuals were studied. the latter included donors with or without c alpha 1 or c alpha 2 gene deletions. monoclonal human iga1 and a genetically engineered iga2 antibody, normal human serum and colostrum iga were used as standards to estimate serum and saliva levels of ag-specific antibodies. in normal individuals, there was a strong iga1 preference of nat ... | 1990 | 2162886 |
| phenotypic selection and characterization of mutant alleles of a eukaryotic dna topoisomerase i. | we have developed a simple, effective genetic screen for mutant alleles of eukaryotic dna topoisomerase i that manifest severely depressed or complete loss of enzymatic function. the screen is based on the extreme toxicity of vaccinia topoisomerase expression in the escherichia coli lysogen strain bl21(de3) and is notable for its ease in distinguishing nonsense mutations (that result in truncated proteins) from missense mutations. the power of the method is evinced by our observation that 100% o ... | 1990 | 2163340 |
| the legionella pneumophila major secretory protein, a protease, is not required for intracellular growth or cell killing. | the legionella pneumophila major secretory protein (msp) is a zn2+ metalloprotease whose function in pathogenesis is unknown. the structural gene for the msp protease, mspa, was isolated from an l. pneumophila genomic library. in escherichia coli which contain plasmids with the mspa gene, msp protein and activity are found in the periplasmic space and the cytoplasm. transposon mutagenesis with tn9 of an mspa-containing plasmid in e. coli yielded mutants which no longer expressed protease activit ... | 1990 | 2164510 |
| potent inhibitory effects of the 5'-triphosphates of (e)-5-(2-bromovinyl)-2'-deoxyuridine and (e)-5-(2-bromovinyl)-1-beta-d-arabinofuranosyluracil on dna polymerase gamma. | (e)-5-(2-bromovinyl)-2'-deoxyuridine 5'-triphosphate (brvdutp) and (e)-5-(2-bromovinyl)-1-beta-d-arabinofuranosyluracil 5'-triphosphate (brvarafutp), which are known as specific inhibitors of herpes simplex viral (type 1 and 2) dna polymerase, were found to be strong inhibitors of dna polymerase gamma from human kb and murine myeloma cells. in fact brvdutp and brvarafutp were found to be stronger inhibitors of dna polymerase gamma than of other dna polymerases having viral (herpes simplex virus ... | 1990 | 2164928 |
| species-specific substrate interaction of picornavirus 3c proteinase suballelic exchange mutants. | the substrate recognition properties of the polio-virus type 1 and coxsackievirus b3 3c proteinases have been examined in vitro by allelic and suballelic exchange of 3c between the cloned virus genomes. the activity of the altered 3c proteinases was examined by translation of synthetic rna in a rabbit reticulocyte lysate/hela cell extract translation system. analysis of the subsequent processing of virus polyproteins by the altered 3c proteinases showed that all of the mutant proteinases maintai ... | 1990 | 2168426 |
| regulation of human monocyte/macrophage function by extracellular matrix. adherence of monocytes to collagen matrices enhances phagocytosis of opsonized bacteria by activation of complement receptors and enhancement of fc receptor function. | in inflammation monocytes emigrate from the peripheral circulation into an extravascular area rich in extracellular matrix proteins. in this milieu, phagocytes ingest and kill invading pathogens. in the present studies, we found that monocytes adhered to type i collagen gels phagocytized 2.5-12-fold more opsonized escherichia coli, staphylococcus aureus, streptococcus pyogenes, and streptococcus pneumoniae than plastic-adherent monocytes. the rate of phagocytosis and the number of bacteria inges ... | 1990 | 2168442 |
| ingestion of legionella micdadei inhibits human neutrophil function. | legionella micdadei is a human pathogen which survives within leukocytes. to determine how this organism escapes intracellular destruction, we examined its effect on human neutrophil activity. neutrophils were allowed to ingest l. micdadei prior to evaluation of functional activity. compared with control cells which did not ingest organisms, cells ingesting l. micdadei showed significantly depressed production of superoxide anion (24.5 +/- 9.0 nmol/10(6) cells per 15 min versus 6.9 +/- 3.2 nmol/ ... | 1990 | 2169462 |
| structural diversity and evolution of human receptor-like protein tyrosine phosphatases. | protein tyrosine phosphatases (ptpases), together with protein tyrosine kinases, regulate the tyrosine phosphorylation that controls cell activities and proliferation. previously, it has been recognized that both cytosolic ptpases and membrane associated, receptor-like ptpases exist. in order to examine the structural diversity of receptor-like ptpases, we isolated human cdna clones that cross-hybridized to a drosophila ptpase cdna clone, dptp12, under non-stringent hybridization conditions. the ... | 1990 | 2170109 |
| specific enzyme-linked immunosorbent assay for the detection of antibodies to the human spumavirus. | recombinant plasmid clones were constructed harbouring the central domains of the outer membrane protein and the transmembrane protein of the env gene of human spumaretrovirus (hsrv). the corresponding fusion proteins were expressed in e. coli, purified and used subsequently to produce antibodies against the hsrv env proteins in rabbits. the authenticity of the bacterially produced domain of the hsrv env proteins was shown by radioimmunoprecipitation of the viral env glycoprotein from hsrv-infec ... | 1990 | 2170434 |
| cloning, sequencing and expression in escherichia coli of cdna for a non-a, non-b hepatitis-associated microtubular aggregates protein. | a 1.7 kb cdna encoding a novel antigen (p44; apparent mr 44k) associated with non-a, non-b (nanb) hepatitis, was isolated from the hepatic cdna library of a chimpanzee infected with nanb hepatitis. the library was screened with a monoclonal antibody against this antigen. the cdna cloned contained an open reading frame encoding a 444 amino acid protein with an mr calculated to be 50,468. the cdna hybridized to a 1.9 kb mrna obtained from chimpanzee hepatocytes infected with either the nanb or hep ... | 1990 | 2170570 |
| construction of isogenic gonococci with variable porin structure: effects on susceptibility to human serum and antibiotics. | protein i (pi) is the most abundant protein on the gonococcal cell surface and besides its porin function it may have important properties contributing to pathogenicity. by allelic exchange using cloned pi genes from fa19 (pia) and ms11 (pib) and a selectable marker introduced closely downstream of these genes, we constructed sets of isogenic gonococcal strains that differ only in their pi gene. analysis revealed that pi has a major effect on stable resistance to normal human serum, and a slight ... | 1990 | 2170812 |
| possible mechanism for preterm labor associated with bacterial infection. i: stimulation of phosphoinositide metabolism by endotoxin in endometrial fibroblasts. | growing evidence suggests an association between intra-amniotic infection and premature initiation of parturition. we recently demonstrated that some factor(s) including endotoxin produced by the organism stimulates endogenous phospholipase a2 resulting in liberation of arachidonic acid and prostaglandin formation (arch. gynecol. obstet. 244: 1-6 (1988). the studies presented in this report were designated to evaluate the mechanism for endotoxin to stimulate phospholipase a2 using human endometr ... | 1990 | 2171111 |
| development of an igm antibody capture test using labelled fusion protein as antigen for diagnosis of b19 human parvovirus infections. | a new anti-b19 igm elisa was developed using the antibody-capture principle. biotinylated fusion protein was used as antigen. the specificity of the test was analysed using sera igm positive to rubella, hepatitis b core antigen, cytomegalovirus and epstein barr virus as well with sera positive for rheumatoid factors, antinuclear antibodies and with sera from normal blood donors. the specificity of the test was 96.18%. one hundred serum samples were tested by the new elisa and the standard macria ... | 1990 | 2171482 |
| e. coli 4.5s rna is part of a ribonucleoprotein particle that has properties related to signal recognition particle. | e. coli 4.5s rna and p48 have been shown to be homologous to srp7s rna and srp54, respectively. here we report that expression of human srp7s in e. coli can suppress the lethality caused by depletion of 4.5s rna. in e. coli, both rnas are associated with p48. in vitro, both e. coli p48 and srp54 specifically bind to 4.5s rna. strains depleted of 4.5s rna strongly accumulate pre-beta-lactamase and fail to accumulate maltose binding protein. these effects commence well before any growth defect is ... | 1990 | 2171778 |
| proton-linked sugar transport systems in bacteria. | the cell membranes of various bacteria contain proton-linked transport systems for d-xylose, l-arabinose, d-galactose, d-glucose, l-rhamnose, l-fucose, lactose, and melibiose. the melibiose transporter of e. coli is linked to both na+ and h+ translocation. the substrate and inhibitor specificities of the monosaccharide transporters are described. by locating, cloning, and sequencing the genes encoding the sugar/h+ transporters in e. coli, the primary sequences of the transport proteins have been ... | 1990 | 2172229 |
| separation and characterization of modified variants of recombinant human insulin-like growth factor i derived from a fusion protein secreted from escherichia coli. | human insulin-like growth factor i, igf-i, was produced in escherichia coli fused to a synthetic igg-binding peptide the fusion protein is secreted into the medium during fermentation and was initially purified on an igg-sepharose column. after hydroxylamine cleavage, igf-i was purified to homogeneity. during purification, impurities in the form of modified variants of igf-i were detected and characterized. the closely related impurities were identified to be a misfolded form of igf-i, having mi ... | 1990 | 2173560 |
| an efficient deletion mutant packaging system for defective herpes simplex virus vectors: potential applications to human gene therapy and neuronal physiology. | we have previously described a defective herpes simplex virus (hsv-1) vector system that permits the introduction of virtually any gene into nonmitotic cells. phsvlac, the prototype vector, stably expresses escherichia coli beta-galactosidase from a constitutive promoter in many human cell lines, in cultured rat neurons from throughout the nervous system, and in cells in the adult rat brain. hsv-1 vectors expressing other genes may prove useful for studying neuronal physiology or performing huma ... | 1990 | 2174168 |
| influence of subinhibitory concentrations of loracarbef (ly 163892) and daptomycin (ly 146032) on bacterial phagocytosis, killing and serum sensitivity. | the aim of this study was to evaluate whether pre-exposure of bacteria to a subinhibitory concentration (sub-mic) of loracarbef (ly 163892) or daptomycin (ly 146032) could modify bacterial susceptibility to serum bactericidal activity and to phagocytosis and killing by murine peritoneal macrophages and by human polymorphonuclear leucocytes. escherichia coli, haemophilus influenzae type b and staphylococcus aureus grown in the presence of one quarter the mic of loracarbef, and s. aureus exposed t ... | 1990 | 2174852 |
| human alpha-n-acetylgalactosaminidase-molecular cloning, nucleotide sequence, and expression of a full-length cdna. homology with human alpha-galactosidase a suggests evolution from a common ancestral gene. | human alpha-n-acetylgalactosaminidase (alpha-galnac, e.c. 3.2.1.49), the lysosomal glycohydrolase that cleaves alpha-n-acetylgalactosaminyl moieties from glycoconjugates, is encoded by a gene localized to chromosome 22q13----qter. the deficient activity of alpha-galnac is the enzymatic defect in schindler disease, an inherited neuroaxonal dystrophy. to isolate a full-length cdna, the enzyme from human lung was purified to homogeneity, 129 non-overlapping amino acids were determined by microseque ... | 1990 | 2174888 |
| expression and characterization of an active human estrogen receptor as a ubiquitin fusion protein from escherichia coli. | the gene coding for the human estrogen receptor protein was expressed as a ubiquitin fusion under the control of the lambda pl promoter in escherichia coli. analysis of extracts by western blot showed that intact receptor protein was produced only when pl promoter was depressed by nalidixic acid at 30 degrees c. to ascertain the intactness of the expressed protein, estrogen receptor in bacterial extracts was titrated with either 17 beta-[3h]estradiol or 17 beta-[125i]iodoestradiol, and the mass ... | 1990 | 2174894 |
| interaction of dntp, pyrophosphate and their analogs with the dntp-binding sites of e. coli dna polymerase i klenow fragment and human dna polymerase alpha. | the 3',5'-exonuclease center of the klenow fragment of e. coli dna polymerase i (fk) was selectively blocked by naf. the latter was shown to forbid the binding of nucleotides and their analogs to the enzyme exonuclease center. in the presence of poly(dt).r(pa)10 template.primer complex and naf, we observed amp, adp, atp, ppi and datp to be competitive inhibitors of the fk-catalyzed dna polymerization. the interactions of the nucleotides with fk and human dna polymerase alpha were compared to rev ... | 1990 | 2176614 |
| site-directed mutations of human growth hormone that selectively modify its lactogenic activity and binding properties. | two novel analogs of human (h) gh, 1) des-7-hgh (arg8met, asp11ala) in which the arg8 was substituted by met and asp11 by ala, and 2) bovine (b) gh/hgh hybrid ii (metala 1-13/14-191, ala11asp) composed of 13 n-terminal amino acid of bgh and elongated by two amino acids (met-ala-1-13) and 14-191 amino acids of hgh, were constructed and expressed in escherichia coli. cd spectra indicated that the alpha-helix content of the purified proteins was similar to that of the native hormone. both analogs r ... | 1990 | 2178223 |
| biologic and biochemic properties of recombinant platelet factor 4 demonstrate identity with the native protein. | platelet factor 4 (pf4) is a 70 amino acid protein released from the alpha-granules of platelets after activation. the exact biologic function of this protein is unknown. we have constructed an expression vector for recombinant pf4 (rpf4) in the t7-based promoter vector pt7-7 to better study the relationship between pf4 structure and function. the protein was expressed in escherichia coli and purified to homogeneity by heparin-agarose affinity chromatography and reverse-phase high-performance li ... | 1990 | 2178704 |
| an active site mutant of human placental alkaline phosphatase with deficient enzymatic activity and preserved immunoreactivity. | | 1990 | 2178808 |
| structure-function analysis of epidermal growth factor: site directed mutagenesis and nuclear magnetic resonance. | the role of leucine-47 in determining the structure and activity of human epidermal growth factor was examined using site-directed mutagenesis. wild type protein and four variants in which leu47 was replaced by valine, glutamate, aspartate and alanine were produced from yeast. 1h nmr experiments demonstrated that substitution of leu47 had little effect on the protein structure. the observed reduction in receptor binding affinity caused by the substitutions could thus be attributed to perturbatio ... | 1990 | 2178977 |
| separation of sublethal and lethal effects of the bactericidal/permeability increasing protein on escherichia coli. | binding of the bactericidal/permeability increasing protein (bpi) of granulocytes to escherichia coli promptly produces several discrete outer envelope alterations and growth arrest without major impairment of bacterial structure or biosynthetic capabilities, raising the question whether these early effects of bpi are sufficient to cause bacterial death. in this study, the bactericidal action of bpi was examined more closely. we have found that bovine or human serum albumin blocks bacterial kill ... | 1990 | 2179269 |
| differences in susceptibility of inbred and outbred infant mice to enterotoxigenic escherichia coli of bovine, porcine and human origin. | infant mice from outbred swiss of1 and from inbred dba/2, c57bl/6, balb/cby and cba strains were screened for usefulness in the diarrhoea model with enterotoxigenic escherichia coli (etec) strains of bovine, porcine and human origin. mouse strains were either weakly susceptible or not susceptible to etec strains of porcine or human origin bearing antigen k88, 987p, cfa/i or cfa/ii. in contrast, some mouse strains were highly susceptible to bovine and porcine etec strains bearing k99 or f41 or bo ... | 1990 | 2179554 |
| cloning, expression, and purification of human cyclophilin in escherichia coli and assessment of the catalytic role of cysteines by site-directed mutagenesis. | the cdna encoding human cyclophilin from the jurkat t-cell lymphoma line has been cloned by the expression cassette polymerase chain reaction and sequenced, and an expression vector has been constructed under control of the tac promoter for efficient expression in escherichia coli. active cyclophilin is produced at up to 40% of soluble cell protein, facilitating a one-column purification to homogeneity. wild-type cyclophilin was characterized for binding of the potent immunosuppressant agent cyc ... | 1990 | 2179953 |
| effects of medium quality on the expression of human interleukin-2 at high cell density in fermentor cultures of escherichia coli k-12. | we examined the ability of transformed escherichia coli cells in fermentor cultures to accumulate interleukin-2 (il-2) intracellularly under temperature-regulated control of the phage lambda pl promoter. induction of expression was undertaken at different culture optical densities, and specific il-2 accumulation was found to decrease with increasing cell density at induction. induction at higher culture optical densities was also accompanied by decreased growth during induction and increased ace ... | 1990 | 2180368 |
| expression and refolding of recombinant human fibroblast procathepsin d. | procathepsin d is a precursor of the human lysosomal protease cathepsin d. due to its short half-life, procathepsin d is difficult to obtain in quantities sufficient to allow structural and enzymatic studies. to obtain large quantities of this precursor, procathepsin d was expressed using the t7 promoter vector pet3a in bacteria that carry a chromosomal copy of the t7 rna polymerase gene under the control of the lac promoter. at high cell density in rich medium, basal levels of t7 rna polymerase ... | 1990 | 2180427 |
| effect of n-methionine-free, bacterially synthesized recombinant human granulocyte-macrophage colony-stimulating factor in a primate model. | we demonstrate the in vivo effects of bacterially synthesized, n-methionine-free recombinant human granulocyte-macrophage colony stimulating factor (rh gm-csf) using a crab-eating monkey model. monkeys were treated with cyclophosphamide (60 mg/kg) and administered with rh gm-csf (30 micrograms/kg/d) subcutaneously (s.c.) for 7 days. within 12 h, a transient increase of neutrophils (greater than 15.0 x 10(9)/l) was observed, and complete recovery of wbc counts was obtained by d 9 (d 16 in control ... | 1990 | 2180740 |
| adhesion of enterotoxigenic escherichia coli to the human colon carcinoma cell line caco-2 in culture. | enterotoxigenic escherichia coli (etec) strains possessing colonization factor antigen i (cfa/i), cfa/ii, cfa/iii, and antigen 2230 were tested for their ability to adhere to the following cell lines: hela, hep-2, hrt 18, hutu 80, mdbk, mdck, vero, and caco-2. etec strains adhered only to the caco-2 cell line. irrespective of the known adhesive factors, the etec strains that adhered to the brush border of human enterocytes also adhered to the caco-2 cell line. the negative variants, which were c ... | 1990 | 2180823 |
| model simulation of a single oral dose of cefuroxime axetil and the related in-vitro kill kinetics against four bacterial species. | an in-vitro model was shown to be capable of simulating a cefuroxime serum profile equivalent to that observed in human volunteer studies, following a single dose of 250 mg cefuroxime axetil. the model was used to carry out kill kinetic studies and showed cefuroxime to lyse the four bacterial test strains, time of onset of lysis being related to the sensitivity of the respective organisms. the more sensitive staphylococcus aureus and haemophilus influenzae strains were subject to a higher absolu ... | 1990 | 2180892 |
| aerobactin and alpha-hemolysin as virulence determinants in escherichia coli isolated from human blood, urine, and stool. | because iron acquisition is essential to the survival of invasive strains of escherichia coli, the frequency of two potential iron acquisition systems, aerobactin and hemolysin production, were compared in e. coli isolated from human blood (n = 95), urine (n = 100), and stool (n = 50). by phenotypic and genotypic methods, the prevalence of hemolysin production was 22% in bacteremic, 38% in urinary, and 22% in fecal isolates of e. coli. aerobactin production was detected in 76% of blood and in 73 ... | 1990 | 2181035 |
| e. coli and urease-induced crystallisation in urine. | the effects of urine preinoculation with e. coli for 20 h on urease activities in urine have been studied in synthetic as well as human urine. the e. coli preinoculation increased ph in both synthetic and human urine. urease enzymatic activity was enhanced in e. coli-preinoculated synthetic urine. the intraluminal urease-induced precipitation was increased in e. coli-preinoculated synthetic urine. the precipitation on glass rods, which more closely reflects crystal growth and aggregation, was re ... | 1990 | 2181636 |
| substrate analogue inhibition and active site titration of purified recombinant hiv-1 protease. | the aspartyl protease of human immunodeficiency virus 1 (hiv-1) has been expressed in escherichia coli at high levels, resulting in the formation of inclusion bodies which contain denatured insoluble aggregates of the protease. after solubilization of these inclusion bodies in guanidinium chloride, the protease was purified to apparent homogeneity by a single-step reverse-phase hplc procedure. the purified, but inactive, protein was denatured in 8 m urea and refolded to produce the active protea ... | 1990 | 2182116 |
| sensitive enzyme immunoassay for human aldolase a. | a sensitive sandwich-type enzyme immunoassay for the aldolase isozyme, a4, was developed using purified antibodies specific to the a subunit of aldolase. the antibodies were raised in sheep being immunized with purified aldolase a4 and then purified by immunoaffinity chromatography on a column of aldolase a4-coupled sepharose. the assay system consisted of polystyrene balls with immobilized antibody f(ab')2 fragments and the same antibody f(ab')2 fragments labeled with beta-d-galactosidase from ... | 1990 | 2182223 |
| escherichia coli f-18 makes a streptomycin-treated mouse large intestine colonization factor when grown in nutrient broth containing glucose. | escherichia coli f-18 fima-, a type 1 fimbria-less derivative of a normal human fecal isolate, e. coli f-18, has previously been shown to be as good a colonizer of streptomycin-treated mouse large intestine as its parent, suggesting that type 1 fimbriae are not necessary in this process. in this study it was found that when e. coli f-18 fima- was grown standing overnight at 37 degrees c in nutrient broth, it remained uniformly suspended; however, when grown in nutrient broth containing 1% (wt/wt ... | 1990 | 2182545 |
| retropseudogenes constitute the major part of the human elongation factor 1 alpha gene family. | the elongation factor 1 alpha (ef-1 alpha) is a protein which promotes the gtp-dependent binding of aminoacyl-trna to ribosomes in the protein synthesis process. a human gene coding for ef-1 alpha has previously been cloned and sequenced along with a pseudo-gene. here, we have further analyzed the family of human ef-1 alpha genes. using an ef-1 alpha cdna as probe twelve genomic ef-1 alpha-like clones were isolated and analyzed. four of these were sequenced and found to contain ef-1 alpha retrop ... | 1990 | 2183196 |
| antipeptide antibodies to two distinct regions of the androgen receptor localize the receptor protein to the nuclei of target cells in the rat and human prostate. | we have developed polyclonal antibodies to two synthetic peptides corresponding to the amino-(n-)terminal or carboxyl-(c-)terminal segments of the human androgen receptor (har) protein, as deduced from the nucleic acid sequence of the androgen receptor cdna. immunoreactive antisera were identified by solid phase enzyme-linked immunosorbent assay and purified by peptide affinity chromatography. specific immunoreactivity with the har was confirmed by immunoblotting, using both a fusion protein pro ... | 1990 | 2184015 |
| in vitro antibacterial effect of yogurt on escherichia coli. | we investigated the bactericidal and bacteriostatic effects of yogurt on three strains of escherichia coli: human toxigenic (078:h11), rabbit pathogenic (rdec-1) and rabbit nonpathogenic [015:k14(l):h4]. approximately 10(6) organisms were incubated in yogurt, milk, broth, and modifications of these materials. aliquots were removed at various intervals and plated on macconkey's agar for enumeration of e. coli. yogurt was bactericidal (at least 5 log10 reduction in bacterial counts) to all three s ... | 1990 | 2185003 |
| cloning and sequencing of mammalian glutathione reductase cdna. | the molecular cloning of a partial cdna to mouse glutathione reductase mrna and of a full-length cdna to the mrna of the human enzyme is described. an initial cdna clone designated lambda grm-b11 was isolated by plaque-screening of an induced mouse cdna expression library in the lambda gt11 vector with a rabbit antibody probe to human glutathione reductase. 125iodine-labelled whole anti-rabbit immunoglobulin was used as second antibody. ecori digestion of the lambda grm-b11 clone released a 720- ... | 1990 | 2185014 |
| evidence for two types of cytotoxic necrotizing factor in human and animal clinical isolates of escherichia coli. | we have characterized the in vitro and in vivo toxic properties of cell sonic extracts from 22 animal and human clinical isolates of escherichia coli that caused both necrosis in the rabbit skin and multinucleation in tissue cultures, two toxic properties previously reported as being specific for e. coli cytotoxic necrotizing factor (cnf). two distinct toxic phenotypes were observed. type 1, which was displayed by originally described cnf strains, was characterized by extensive multinucleation a ... | 1990 | 2185259 |
| identification of a mammalian nuclear factor and human cdna-encoded proteins that recognize dna containing apurinic sites. | damage to dna can have lethal or mutagenic consequences for cells unless it is detected and repaired by cellular proteins. repair depends on the ability of cellular factors to distinguish the damaged sites. electrophoretic binding assays were used to identify a factor from the nuclei of mammalian cells that bound to dna containing apurinic sites. a binding assay based on the use of beta-galactosidase fusion proteins was subsequently used to isolate recombinant clones of human cdnas that encoded ... | 1990 | 2185469 |
| an enzymatic method for the kinetic measurement of l-asparaginase activity and l-asparagine with an ammonia gas-sensing electrode. | a simple kinetic method to assay l-asparaginase and l-asparagine with an ammonia gas-sensing electrode is described. the method is based upon the de-amination of l-asparagine by l-asparaginase from escherichia coli, resulting in the production of ammonia. the initial rate (mv/min) of ammonia release is proportional to the activity of l-asparaginase and also to the concentration of l-asparagine in the presence of a large amount of the enzyme. optimal temperature, buffer composition and ph for the ... | 1990 | 2186873 |
| specific enzymatic assay for d-glucarate in human serum. | a sensitive and specific spectrophotometric assay was developed to determine levels of d-glucarate in human serum. this assay makes use of the escherichia coli glucarate catabolic enzymes d-glucarate dehydrase, alpha-keto-beta-deoxy-d-glucarate aldolase, and tartronate semialdehyde (tsa) reductase, to convert d-glucarate to equimolar quantities of pyruvate and tsa. in a one-tube reaction that included nadh, lactate dehydrogenase, and the three e. coli enzymes, 1 mumol of d-glucarate was quantita ... | 1990 | 2187374 |
| a simple escherichia coli system for monitoring hiv protease activity: analysis of two temperature-sensitive protease mutants. | a simple escherichia coli system has been developed for the detection of human immunodeficiency virus (hiv) protease activity. in this system, the protease sequence is placed downstream of the hiv gag polypeptide in an operon arrangement. upon expression of the operon, gag serves as the substrate for the protease; the level of protease activity can be determined by measurement of the cleavage product of gag in cell extracts by western immunoblotting. this system is useful in both detection of pr ... | 1990 | 2187504 |
| enhancement of the gdp-gtp exchange of ras proteins by the carboxyl-terminal domain of scd25. | in saccharomyces cerevisiae, the product of the cdc25 gene controls the ras-mediated production of adenosine 3',5'-monophosphate (camp). in vivo the carboxyl-terminal third of the cdc25 gene product is sufficient for the activation of adenylate cyclase. the 3'-terminal part of scd25, a gene of s. cerevisiae structurally related to cdc25, can suppress the requirement for cdc25. partially purified preparations of the carboxy-terminal domain of the scd25 gene product enhanced the exchange rate of g ... | 1990 | 2188363 |
| demonstration of enterotoxigenic escherichia coli in diarrheic broiler chicks. | an investigation was made to survey the possible presence of enterotoxigenic escherichia coli (etec) in the stools of diarrheal chicks. we analyzed two outbreaks of diarrhea in broiler chicks at two independent farms in the philippines, from which no pathogens other than escherichia coli were found. in one outbreak at farm #1, all 42 isolates produced heat-labile enterotoxin (lt), with 3 of these isolates also producing heat-stable enterotoxin (st). the o serotypes of 15 strains tested randomly ... | 1990 | 2188851 |
| cdna cloning and chromosomal assignment of the human o6-methylguanine-dna methyltransferase. cdna expression in escherichia coli and gene expression in human cells. | the o6-methylguanine-dna methyltransferases are the most common form of cellular defense against the biological effects of o6-methylguanine in dna. by screening a cdna library with oligonucleotide probes derived from the active site amino acid sequence of the bovine methyltransferase, we have isolated a cdna clone for the human enzyme. the cdna contains a single open reading frame encoding a protein of mr 21,700 which exhibits considerable homology to three bacterial methyltransferases. when pro ... | 1990 | 2188979 |
| activation of transcription by hiv-1 tat protein tethered to nascent rna through another protein. | the human immunodeficiency virus type i (hiv-1) nuclear protein tat is a potent activator of viral gene transcription. activation by tat requires a cis-acting element, the transactivation response (tar) site, located immediately downstream of the transcription start site. several observations suggest that tar functions as the nascent rna product of the hiv long-terminal-repeat promoter (for a review, see ref. 6). indeed, tat protein and several cellular proteins bind directly to nascent tar rna ... | 1990 | 2190099 |
| oligonucleotide correlations between infector and host genomes hint at evolutionary relationships. | the frequencies of oligonucleotides of length 3-6 were studied in 211 sequences of human dna (659 kilobases), 22 sequences of dna of human viruses (120 kbs), in 181 sequences of e. coli (442 kbs), and in 42 sequences of phages of e. coli (137 kbs). the sequences were obtained from genbank(r) 48. the observed frequencies (o) were compared to the expected frequencies (e) obtained in two ways: 1) according to nucleotide composition for each series, and 2) according to first order markow chains for ... | 1990 | 2190185 |
| peptidyl-prolyl cis-trans-isomerase from escherichia coli: a periplasmic homolog of cyclophilin that is not inhibited by cyclosporin a. | the prokaryotic peptidyl-prolyl cis-trans-isomerase called "rotamase", a homolog of the human cyclophilin, has been identified in escherichia coli. the e. coli rotamase, a product of the gene we suggest be called "rot," has been purified to homogeneity after cloning of the gene by the polymerase chain reaction and its overexpression in e. coli. based on the chymotrypsin-coupled assay using the tetrapeptide substrate succinyl-ala-ala-pro-phe-p-nitroanilide, the purified protein has rotamase activ ... | 1990 | 2190212 |
| isolation and nucleotide sequence determination of a gene encoding a heat-stable enterotoxin of escherichia coli. | an enterotoxin-producing strain of e. coli has been isolated from an infant patient in shanghai children hospital and the gene of its heat-stable enterotoxin has been cloned and sequenced. the pre-pro-sti was composed of 72 amino acid residues corresponding to the encoding of 216 base pairs. there was only one nucleotide difference in the pro-part between this sti gene and the stib gene reported in the literature. a guanosine base in our sti gene was substituted for a cytosine base in stib gene ... | 1990 | 2190361 |
| expression and biochemical characterization of human immunodeficiency virus type 1 nef gene product. | nef genes from human immunodeficiency virus type 1 isolates bh10 and lav1 (lymphadenopathy-associated virus type 1) were expressed in escherichia coli under the deo operon promoter. the two proteins found in the soluble compartment of the bacterial lysate were purified by ion-exchange column chromatography to apparent homogeneity. determination of the amino-terminal sequence revealed glycine as the first amino acid in the nef protein, indicating removal of the initiator methionine during express ... | 1990 | 2191151 |
| transcriptional activation of the human immunodeficiency virus type 1 long terminal repeat by hepatitis b virus x-protein requires de novo protein synthesis. | human hepatitis b virus (hbv) x-gene, previously shown to be capable of trans-activating heterologous regulatory elements of the human beta-interferon gene, the human immunodeficiency virus type i (hiv-1) long terminal repeat (ltr), the simian virus 40 (sv40), and hbv, has the capacity to code for a 17-kda polypeptide (designated px17). we now report that px17 synthesized in escherichia coli can activate transcription controlled by the hiv-1 ltr using a protoplast fusion technique. protoplasts o ... | 1990 | 2191500 |
| production of recombinant human tropoelastin: characterization and demonstration of immunologic and chemotactic activity. | tropoelastin cannot readily be prepared in quantity from natural sources and this has limited research in several important areas including structure/function relationships and fiber assembly. in order to eliminate this limitation, human tropoelastin has been expressed in a recombinant bacterial system and the protein has been highly purified. the size, amino acid composition, and sequence of the amino terminus of the recombinant tropoelastin (rte) all agree with values predicted by the nucleoti ... | 1990 | 2191629 |
| aerobactin uptake system, colv production, and drug resistance encoded by a plasmid from an urinary tract infection escherichia coli strain of human origin. | a study of escherichia coli strains isolated from patients suffering from urinary tract infections in ljubljana, yugoslavia, revealed a plasmid encoding the aerobactin iron uptake system, colv production, and drug resistance. the plasmid is conjugative and at least 85 kilobases in length. | 1990 | 2192786 |
| a cdna for a protein that interacts with the human immunodeficiency virus tat transactivator. | the human immunodeficiency virus (hiv) tat protein (tat) is a positive regulator of virus gene expression and replication. biotinylated tat was used as a probe to screen a lambda gt11 fusion protein library, and a complementary dna encoding a protein that interacts with tat was cloned. expression of this protein, designated tbp-1 (for tat binding protein-1), was observed in a variety of cell lines, with expression being highest in human cells. tbp-1 was localized predominantly in the nucleus, wh ... | 1990 | 2194290 |
| in vivo processing of n-terminal methionine in e. coli. | the processing of amino-terminal methionine from cytosolic proteins in e. coli has been investigated in vivo, using amino-terminal-extended human growth hormone (hgh) as a model system. twenty different hgh-genes with the sequence met-xxx-glu-glu-hgh where xxx denotes each of the 20 different amino acids, were constructed and expressed in e. coli. following purification of the products, the n-terminal amino acid sequences (10 cycles) were determined. the results demonstrate that the removal of m ... | 1990 | 2194835 |
| [interaction of bactericidal serum effect and antibiotics in subminimal inhibitory concentrations on e. coli strains]. | imipenem (imi) forming round cells in gram negative rods reduces in subinhibitory concentrations (submic) the seroresistance of e. coli. this effect is distinctly more pronounced in a moderately seroresistant strain of e. coli than in a high seroresistant one. conversely, human serum (hs) increases the sensitivity of e. coli strains to imi dependent on their original seroresistance. in contrast, ampicillin (amp), a filament inducer in e. coli, reduces equally seroresistance but only to a minimal ... | 1990 | 2195453 |
| characterization of epidermal growth factor receptors on plasma membranes isolated from rat gastric mucosa. | the binding of human epidermal growth factor (hegf), beta-urogastrone, to plasma membranes isolated from rat gastric mucosa was studied to characterize gastric egf receptors. the binding of [125i]hegf was temperature dependent, reversible, and saturable. a single class of binding sites for egf with a dissociation constant of 0.42 nm and maximal binding capacity of 42 fmol/mg protein was suggested. there was little change in the binding of [125i]hegf upon addition of peptide hormones (secretin, i ... | 1990 | 2195496 |
| multiple cdna clones encoding nuclear proteins that bind to the tax-dependent enhancer of htlv-1: all contain a leucine zipper structure and basic amino acid domain. | a trans-activator protein, p40tax, of human t cell leukemia virus type 1 (htlv-1) activates its own promoter and cellular promoters of il-2, il-2 receptor alpha and gm-csf genes. we isolated three cdna clones encoding cellular proteins that bind to the p40tax-dependent enhancer of htlv-1 by screening a lambda gt11 cdna library of an htlv-1 infected cell line. all three proteins, treb5, treb7 and treb36, contained a leucine zipper structure and basic amino acid domain, which are conserved in fos, ... | 1990 | 2196176 |
| virulent escherichia coli strains for chicks bind fibronectin and type ii collagen. | 125i-fibronectin and 125i-collagen (type ii) binding was detected in escherichia coli strains isolated from chickens and poults. high fibronectin binding-strains also bind the 29 kd aminoterminal fragment of fibronectin. binding properties in strain ck28 were partially characterized. the highest binding of 125i-fibronectin and 125i-collagen for strain ck28 was obtained with bacteria grown at 33 degrees c. binding of 125i-fibronectin, its 125i-29 kd fragment, and 125i-collagen, was very rapid, re ... | 1990 | 2196415 |
| an attempt to unify the structure of polymerases. | with the great availability of sequences from rna- and dna-dependent rna and dna polymerases, it has become possible to delineate a few highly conserved regions for various polymerase types. in this work a dna polymerase sequence from bacteriophage spo2 was found to be homologous to the polymerase domain of the klenow fragment of polymerase i from escherichia coli, which is known to be closely related to those from staphylococcus pneumoniae, thermus aquaticus and bacteriophages t7 and t5. the al ... | 1990 | 2196557 |
| a statewide outbreak of escherichia coli o157:h7 infections in washington state. | in november 1986, a statewide outbreak of escherichia coli o157:h7 infections in washington state was identified after a physician in an eastern washington community hospitalized three patients with hemorrhagic colitis which progressed to thrombotic thrombocytopenic purpura. epidemiologic investigation identified 37 cases in this community and linked the illnesses to a local restaurant which had served ground beef that was the suspected initial vehicle of transmission. the plasmid profile and to ... | 1990 | 2196790 |
| synthesis of a new helical protein: the effect of secondary structure rearrangement on structure formation. | a new helical protein was designed and synthesized to alter the sequential connectivity of the 4 helices in human growth hormone and to delete the long surface loop structures. the protein accumulated as an insoluble form in e. coli was solubilized and purified to apparent homogeneity in the presence of 7m urea, and refolded by the aid of 1% n-octyl-beta-d-glucopyranoside. the circular dichroism spectrum was typical of a highly helical protein. the molecular weight estimated by gel permeation ch ... | 1990 | 2196876 |
| an f factor based cloning system for large dna fragments. | an effective technique using an escherichia coli plasmid system was developed to clone fragments of exogenous dna of as large as 100 kilobase pairs. the characteristic features of this technique are the use of a low copy number (one to two) mini-f based plasmid vector and the introduction of artificial lambda cosr ends into the termini of dna sources and then of the cosl ends into those of linearized vector molecules. this terminal modification greatly facilitated the formation of active large r ... | 1990 | 2197597 |
| cloning and characterization of kluyveromyces lactis sec14, a gene whose product stimulates golgi secretory function in saccharomyces cerevisiae. | the saccharomyces cerevisiae sec14 gene encodes a cytosolic factor that is required for secretory protein movement from the golgi complex. that some conservation of sec14p function may exist was initially suggested by experiments that revealed immunoreactive polypeptides in cell extracts of the divergent yeasts kluyveromyces lactis and schizosaccharomyces pombe. we have cloned and characterized the k. lactis sec14 gene (sec14kl). immunoprecipitation experiments indicated that sec14kl encoded the ... | 1990 | 2198263 |
| construction of escherichia coli vectors for expression and mutagenesis: synthesis of human c-myc protein that is initiated at a non-aug codon in exon 1. | three types of escherichia coli vector for both gene expression and mutagenesis were constructed from a plasmid/phage chimera vector puc118. each vector contains the lac (ptd-lac), tac (ptd-tac), or t7 promoter (ptd-t7). downstream from the promoter, these vectors have sequences in common, including a shine-dalgarno (sd), multiple cloning sequence, sequence-primer binding site, transcription termination signal, and m13 origin of replication. using single-stranded circular dna obtained by infecti ... | 1990 | 2199326 |
| substrate overlap and functional competition between human nucleotide excision repair and escherichia coli photolyase and (a)bc excision nuclease. | human cell free extract prepared by the method of manley et al. (1980) carries out repair synthesis on uv-irradiated dna. removal of pyrimidine dimers by photoreactivation with dna photolyase reduces repair synthesis by about 50%. with excess enzyme in the reaction mixture photolyase reduced the repair signal by the same amount even in the absence of photoreactivating light, presumably by binding to pyrimidine dimers and interfering with the binding of human damage recognition protein. similarly ... | 1990 | 2200513 |
| molecular cloning and nucleotide sequence of another variant of the escherichia coli shiga-like toxin ii family. | escherichia coli strain h.i.8 (o128:b12) produces low levels of a shiga-like toxin (slt) which we have called sltiiva because of its close relationship with sltiiv. the vero cell cytotoxicity of sltiiva is neutralized by antisera against sltii and sltiiv but not by antisera against slti. these data indicate that the slt of strain h.i.8 is a member of the sltii family. since sltiiva shares with sltiiv the property of having low cytotoxicity to hela cells compared with vero cells, it is appropriat ... | 1990 | 2200845 |
| function of the human immunodeficiency virus types 1 and 2 rev proteins is dependent on their ability to interact with a structured region present in env gene mrna. | the interaction of the human immunodeficiency virus type 1 (hiv-1) rev protein with a structured region in env mrna (the rev-responsive element [rre]) mediates the export of structural mrnas from the nucleus to the cytoplasm. we demonstrated that unlike hiv-1 rev, which functions with both the hiv-1 and hiv-2 rres, hiv-2 rev functions only with the hiv-2 rre. rev-rre binding studies suggested that the lack of nonreciprocal complementation stems from the inability of hiv-2 rev to interact with hi ... | 1990 | 2200888 |
| [the effect of the cationic proteins of human blood cells on the growth of escherichia coli]. | the antibacterial effect of cationic proteins (cp) on donor leukocytes and thrombocytes with respect to the growth of e. coli has been demonstrated in vitro, the maximum recorded inhibition being caused by the action of leukocytic cp. differences in the inhibitory action may be linked with the presence of anomalies in the amino acid composition of leukocytic cp and thrombocytic cp, manifested by the deterioration of the basic properties of the latter, as well as by the fractional composition who ... | 1990 | 2201153 |
| thyroid hormone binding protein contains glycosylation site binding protein activity. | several lines of evidence provided by other workers indicate that within the same species thyroid hormone binding protein, the beta-subunit of prolyl hydroxylase, and protein disulfide isomerase are the same protein. we sought to determine if glycosylation site binding protein, a lumenal protein of the endoplasmic reticulum, also has the same primary structure. to accomplish this the level of glycosylation site binding protein (gsbp) activity, measured by photolabeling with a glycosylation site ... | 1990 | 2202300 |
| the heat-stable toxin i gene from escherichia coli 18d. | the heat-stable toxin i gene in the human escherichia coli isolate 18d is the esta1 allele. the gene is not part of a composite transposon, but inspection of the flanking dna sequences suggests that it was at one time part of a transposon. the hypothetical transposon originated from an event other than the occurrence that formed tn1681. | 1990 | 2203756 |
| ligand-specific transactivation of gene expression by a derivative of the human glucocorticoid receptor expressed in yeast. | in this study we have reconstituted transactivation of gene expression by the human glucocorticoid receptor in the yeast, saccharomyces cerevisiae. we have expressed the c-terminal half of the human glucocorticoid receptor (residues 415-777), the smallest derivative that can be expected to function as a ligand-dependent activator of transcription, in yeast cells. the function of the expressed protein has been assayed using a reporter gene consisting of the beta-galactosidase gene from escherichi ... | 1990 | 2203760 |
| modulation of hla-dr expression in epithelial cells by interleukin 1 and estradiol-17 beta. | both ultrapure human interleukin-1 (il-1) and escherichia coli derived recombinant il-1 alpha and beta consistently induced the expression of major histocompatibility class ii (hla-dr) molecules in a human endometrial and a breast carcinoma cell line. [35s]methionine incorporation into il-1 induced, immunoprecipitable hla-dr molecules demonstrated de novo synthesis of both light and heavy chains of the hla-dr molecules. lipopolysaccharide, recombinant interleukin-2 and recombinant interleukin-6 ... | 1990 | 2203800 |
| preparation and characterization of human interleukin-5 expressed in recombinant escherichia coli. | the gene coding for human interleukin-5 was synthesized and expressed in escherichia coli under control of a heat-inducible promoter. high-level expression, 10-15% of total cellular protein, was achieved in e. coli. the protein was produced in an insoluble state. a simple extraction, renaturation and purification scheme is described. the recombinant protein was found to be a homodimer, similar to the natural murine-derived protein. despite the lack of glycosylation, high specific activities were ... | 1990 | 2205201 |
| expression in escherichia coli of the aids virus aspartic protease through a protein fusion. | fusion of the coding sequence for the aspartic protease of hiv-1, the human aids virus, to a bacterial beta-lactamase gene, provides an expression system in e. coli which yields high specific activity hiv protease in a soluble form. | 1990 | 2205238 |
| immunity related to exposition and bacterial colonization of the infant. | | 1990 | 2206000 |