Showing papers on "Ultraviolet light published in 1983"
TL;DR: It is demonstrated that lon proteolysis affects the stability of a native E. coli Protein, confirming the hypothesis that the product of the sulA gene is degraded by lon proteins.
Abstract: Escherichia coli lon mutants are defective in the ATP-dependent proteolysis of abnormal proteins. The mutants are also sensitive to ultraviolet light (UV) in that septation is inhibited after exposure to UV. sulA mutations, isolated as suppressors of UV sensitivity unlinked to lon, do not affect proteolysis but allow septation to occur after DNA damage. We have confirmed the hypothesis that the product of the sulA gene is degraded by lon proteolysis. If sulA (the product of sulA) is a UV-inducible division inhibitor, as suggested by a variety of experiments, lon (the product of lon) may regulate cell division by regulating the half-life of sulA. We cloned the sulA gene in a bacteriophage lambda vector from a plasmid carrying the ompA region of E. coli. An 18-kilodalton polypeptide was identified as the product of the sulA gene. Pulse-chase labeling demonstrated that the half-life of the sulA protein is 1.2 min in lon+ cells and 19 min in lon- cells. This work demonstrates that lon proteolysis affects the stability of a native E. coli protein.
345 citations
TL;DR: Evidence in favor of the existence of skin-associated lymphoid tissues (SALT) includes that the cutaneous microenvironment is capable on its own of accepting, processing, and presenting nominal antigen, and subsets of T lymphocytes display differential affinity for skin and its associated peripheral nodes.
343 citations
TL;DR: In this paper, the X-ray structure analysis and refinement at 1·9 A resolution of calf γ-II crystallin, a lens-specific protein, has been reported, which has a symmetrical, hierarchical structure of two globular domains each comprising two similar “Greek key” motifs, consecutive along the polypeptide chain, and related by a pseudo 2-fold axis.
278 citations
TL;DR: Through a combination of subcloning and Tn1000 mutagenesis, a region of 2.2 X 10(3) bases which contains the information necessary to complement umuC mutations is identified which is essential for "error-prone repair" in E. coli.
275 citations
TL;DR: In this article, a procedure for the rapid preparation of phenacyl and naphthacyl derivatives of fatty acids was described, and the derivatives of saturated, monounsaturated, and polyunsaturated fatty acids were analyzed by highperformance liquid chromatography (HPLC) on a C18 reversed-phase column at nanogram sensitivity.
190 citations
TL;DR: The Induction of the SOS System-Untargeted Mutagenesis Results in Mutations and Mechanisms of FrameshiftMutagenesis are studied.
Abstract: INTRODUCTIO N . . . . ..... . . . . . . . . . . . . . . . . . . ... .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 5 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 6 MUTAGENI C PATHWAyS . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216 SPECIFI CITY OF SOS-DEPENDE NT MUTAGENS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218 Compounds Forming Bulky Adducts . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .... . . . . . . . . . . . .. . . . . . . . . . 2 19 Antitumor Drugs .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 1 Mutations Resulting from the Induction of the SOS System-Untargeted Mutagenesis? 222 Ultraviolet Light . . . . . . . . . . . . . . . . . . ... :... . . . . . . . . . . ....... . . . . . . . . . . . ..... . . . . . . . . . . ... . . . . . . . . . . . 226 HOTSPOTS-S ITE SPE CIFICITy . ...... . . . . . . . . . . . ...... . . . . . . . . . . ..... . . . . . . . . . ,... . . . . . . . . . . . . 230 FRAMESHIFTS . . . . . . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .... . . . 231 Mechanisms of Frameshift Mutagenesis . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . 234
186 citations
TL;DR: Satisfactory precision could be obtained in DNA quantification by epifluorescent cytophotometry on DAPI stained speciments by reducing the DAPI concentration to 50 ng/ml and light scattering became negligible after reducing the intensity of the excitation light.
Abstract: DNA-DAPI complexes emit strong bluish white fluorescence when excited by ultraviolet light so that even very small amounts of DNA such as those in mitochondria, chloroplasts, and virus particles can be visualized. Moreover, the staining procedure with DAPI is very simple and requires no hydrolysis. However, DAPI staining was considered unsuitable for quantitative purpose; nonspecific cytoplasmic fluorescence, scattering of strong emission light, and fading of the fluorescence under UV excitation were major problems of DAPI staining in quantitative cytofluorometry. We found that (1) nonspecific cytoplasmic fluorescence could be eliminated by reducing the DAPI concentration to 50 ng/ml, (2) fluorescence decay was markedly decreased by adding electron donors and molecules containing SH radicals in the mounting media, and (3) light scattering became negligible after reducing the intensity of the excitation light. Thus satisfactory precision could be obtained in DNA quantification by epifluorescent cytophotometry on DAPI stained specimens.
161 citations
TL;DR: The response of pure cultures of Escherichia coli, Candida parapsilosis, and bacterial virus f2 to ultraviolet light radiation was studied in a batch reactor and in a completely mixed, flow-through annular reactor, finding the series-event model to be superior to multi-target kinetics.
154 citations
126 citations
TL;DR: Inhibition of poly(ADP-ribose) synthesis by 3-aminobenzamide in various human and hamster cells influenced the responses to DNA damage from methyl methanesulfonate, but not from ultraviolet light.
116 citations
Patent•
24 Oct 1983TL;DR: In this article, stabilized polyester compositions with significantly improved weatherability have been presented, which consist of copolyesterethers derived from a dicarboxylic acid component and a glycol component.
Abstract: Disclosed are stabilized polyester compositions having significantly improved weatherability. These polyesters consist of copolyesterethers derived from a dicarboxylic acid component comprising about 80-100 mole % 1,4-cyclohexanedicarboxylic acid having a trans isomer content of at least 70% and about 0-20 mole % of a second dicarboxylic acid and a glycol component comprising about 70-95 mole % 1,4-cyclohexanedimethanol and about 5-30 mole % of a polyalkylene ether glycol having a molecular weight of about 600 to about 3000. The copolyesterether compositions further comprise a stabilizing effective amount of the combination of (1) at least one hindered phenolic antioxidant, (2) at least one ultraviolet light stabilizing compound compatible with said copolyesterether and (3) at least one hindered amine light stabilizing compound having the formulae ##STR1## the groups shown as R1, R2, R3 and R4 are each independently selected from various substituents.
TL;DR: Using defined monoclonal T-cell probes and tumour variants selected in vitro with these probes, it is found that the total antigenicity consisted of multiple independent components, all of which were tumour-specific and expressed simultaneously on the same tumour cell.
Abstract: Tumours induced by physical or chemical carcinogens often express tumour-specific antigens that can induce strong protective immune defence in the host. The diversity of these unique antigens among different tumours is seemingly endless, and has been compared to that of immune receptors. At present, the nature and complexity of this antigenicity is not known for any single tumour. Here we describe the unique antigenicity expressed by a murine ultraviolet light (UV)-induced fibrosarcoma. This tumour is clearly subject to immune surveillance by the normal host, and does not grow progressively unless it undergoes antigenic changes. Using defined monoclonal T-cell probes and tumour variants selected in vitro with these probes, we found that the total antigenicity consisted of multiple independent components, all of which were tumour-specific and expressed simultaneously on the same tumour cell. The demonstration of this antigenic complexity will enable us to identify and compare the molecular composition of the components of this antigen, as well as to determine their individual roles in tumour rejection and escape.
TL;DR: In this article, the degree of radiation damage induced in GaAs by ion-beam etching with Ar, reactive ion etch with CF4 and CHF3, and ionbeam-assisted etched with Ar and Cl2 was evaluated.
Abstract: A number of dry etching techniques have been developed and their ability to produce anisotropic etch profiles has been demonstrated. In addition to etch anisotropy, an important consideration for device and circuit fabrication is whether a sample suffers radiation damage by exposure to ions, electrons, or ultraviolet light during etching. In this study we evaluate the degree of radiation damage induced in GaAs by ion‐beam etching with Ar, reactive‐ion etching with CF4 and CHF3, and ion‐beam‐assisted etching with Ar and Cl2. In addition, we propose and demonstrate processing techniques which can be used after dry etching to reduce the effects of radiation damage. GaAs samples were etched under a variety of etching conditions. The degree of radiation damage caused by etching was determined by evaluating Schottky diodes fabricated on the etched surfaces and by using deep level transient spectroscopy to characterize trapping centers. It was found that the barrier heights and breakdown voltages of Schottky diodes were changed after etching. Also, an increase in the density of traps was observed. Variations in the etching conditions had a strong effect on the measured characteristics of the samples.
TL;DR: It is concluded that the strychnine binding site of the glycine receptor is located on a protease-inaccessible domain of the 48000-Mr subunit, which suggests that photocrosslinking of [3H]strychnines may require energy transfer from specific groups of its high-affinity receptor binding site.
Abstract: The irreversible incorporation upon ultraviolet illumination of the glycine receptor antagonist, [3H]strychnine, into synaptic membrane fractions of rat spinal cord has been investigated. The specificity of this photoaffinity-labelling reaction for the glycine receptor was demonstrated by the following results: (a) the Kd value (9.7 nM) of the glycine-displaceable irreversible incorporation of [3H]strychnine was similar to the previously reported Kd of [3H]strychnine binding to the glycine receptor; (b) pre-illumination of the membranes with unlabelled strychnine led to a corresponding reduction in the number, but not the affinity, of reversible glycine-displaceable [3H]strychnine binding sites; (c) the ultraviolet light-induced incorporation into the membranes of [3H]strychnine was inhibited by different glycine receptor agonists; other neurotransmitter substances had little or no effect. Also, [3H]strychnine alone was shown to be stable upon illumination with ultraviolet light; this suggests that photocrosslinking of [3H]strychnine may require energy transfer from specific groups of its high-affinity receptor binding site. Upon sodium dodecyl sulphate/polyacrylamide gel electrophoresis a single labelled polypeptide with a relative molecular mass of 48000 was revealed from spinal cord membranes photoaffinity-labelled with [3H]strychnine. Spinal cord membranes photoaffinity-labelled with the gamma-aminobutyric acid receptor ligand [3H]flunitrazepam, however, gave a single polypeptide with a relative molecular mass of 5- 0000. Treatment of membranes, labelled with [3H]strychnine, by endoglycosidase H did not alter the relative molecular mass of the 48000-Mr labelled polypeptide. Trypsin treatment, on the other hand, successively produced major fragments of relative molecular masses of 42000 and 37000. Also, even after extensive treatment with trypsin or chymotrypsin, greater than or equal to 90% of the radioactivity incorporated into the labelled membranes remained membrane-associated. It is concluded that the strychnine binding site of the glycine receptor is located on a protease-inaccessible, i.e. probably hydrophobic domain of the 48000-Mr subunit.
Patent•
23 Nov 1983
TL;DR: In this paper, a process for composite plastic pipe is described, which comprises producing a thermoplastic resin pipe by an extruder, covering the surface of the pipe (I) uniformly with a continuous fibrous reinforcing material (II) impregnated with a thermosetting resin in its axial direction by a draw molding method, helically winding a continuous fiber-reinforcement material (III) impregating or not impregnating with a thermmosetting resins uniformly on the layer of the fibrous reinforcement material by a filament winding method, thereafter curing
Abstract: A process for producing a composite plastic pipe, which comprises producing a thermoplastic resin pipe (I) by an extruder, covering the surface of the pipe (I) uniformly with a continuous fibrous reinforcing material (II) impregnated with a thermosetting resin in its axial direction by a draw molding method, helically winding a continuous fibrous reinforcing material (III) impregnated or not impregnated with a thermosetting resin uniformly on the layer of the resin fibrous reinforcing material (II) by a filament winding method, thereafter curing the thermosetting resin by irradiation of ultraviolet light and coating a thermoplastic resin (IV) on the resulting product within a crosshead die in an extruder.
TL;DR: E. coli 16S RNA in solution was photoreacted with hydroxymethyltrimethylpsoralen and long wave ultraviolet light to yield direct information about the secondary structure of large RNAs, which should prove invaluable in studying the structure of other RNAs of all sizes.
TL;DR: It was found that up to a 3 M concentration of the salt, caesium cations induced a gradual rearrangement of the polynucleotide double helix during which the phosphodiester bonds in one sequence changed the geometry and the base stacking decreased.
TL;DR: The results indicate that wild-type D. radiodurans possesses two pathways for the excision of pyrimidine dimers and that mutational blocks in both must exist for theexcisionless phenotype to be expressed.
Abstract: A mutant of Deinococcus (formerly Micrococcus) radiodurans (strain 302, mutant in mtcA) sensitive to both the lethal effect of mitomycin C and the mutagenic effect of simple alkylating agents, but having wild-type resistance to UV light, was treated with the mutagen N-methyl-N'-nitro-N-nitrosoguanidine in an attempt to isolate strains deficient in the ability to excise UV-induced pyrimidine dimers. Three strains were isolated that were UV-sensitive, but had wild-type resistance to the lethal effect of methyl methanesulphonate and all were shown to be unable to excise pyrimidine dimers. The three strains UVS9, UVS25 and UVS78 had, in addition to the mutation in mtcA, mutations in loci designated uvsC, uvsD and uvsE, respectively. When the mutant mtcA gene was replaced by its wild-type allele in all three strains they became UV- and mitomycin C-resistant. On incubating the double mutants UVS9, UVS25 and UVS78 with wild-type DNA about 50% of the transformants selected for UV resistance were mitomycin C-sensitive and about 50% resistant depending on whether the mutant mtcA or the uvsC, D or E genes had been replaced by their wild-type alleles. Although strains mutant singly in uvsC, D or E were UV-resistant the rates of excision of pyrimidine dimers differed between them and was slower in all of them than in the wild-type and strain 302. The results indicate that wild-type D. radiodurans possesses two pathways for the excision of pyrimidine dimers and that mutational blocks in both must exist for the excisionless phenotype to be expressed.
TL;DR: An absolute method for single aerosol particle mass and charge measurement has been developed in this article, which involves suspension of a charged particle in an electrodynamic chamber called a quadrupole, and the voltage required to balance the particle against gravity, the particle charge-to-mass ratio can be measured.
TL;DR: The net effect of lon-mutations was to increase the concentration of mutant sigma, and it is concluded that the temperature-sensitive phenotype results from insufficient concentration, rather than altered function, of the mutant protein.
TL;DR: These studies, therefore, do not support the hypothesis that liver cell plasma membranes contain a specific albumin receptor and affinity chromatography over albumin/agarose gel of solubilized membrane proteins provided no evidence of a membrane protein with a high affinity for albumin.
TL;DR: Ultraviolet light readily induced both auxotrophic and morphological mutants in isolates of F. moniliforme from corn and sorghum, and a genetic map with several instances of linkage was yielded.
TL;DR: This treatment is donor blood-specific and has produced greater than 160-day survival of transplanted islets without the administration of immunosuppressive agents.
Abstract: Survival of allografts of islets of Langerhans in nonimmunosuppressed adult rats was prolonged by transfusions of donor blood irradiated with ultraviolet light before transplantation across a major histocompatibility barrier. This treatment is donor blood-specific and has produced greater than 160-day survival of transplanted islets without the administration of immunosuppressive agents.
Journal Article•
TL;DR: 3-Aminobenzamide, an inhibitor of polyadenosine diphosphoribose polymerase, produced rapid reversible changes in single-strand break frequencies in DNA from primary human fibroblasts damaged by alkylating agents, but it did not cause such changes in the DNA of cells damaged by ultraviolet light.
Abstract: 3-Aminobenzamide, an inhibitor of polyadenosine diphosphoribose polymerase, produced rapid reversible changes in single-strand break frequencies in DNA from primary human fibroblasts damaged by alkylating agents, but it did not cause such changes in the DNA of cells damaged by ultraviolet light. The increase in single-strand peak frequencies was not due to an accumulation of blocked repair sites, such as occurs with DNA polymerase inhibitors, but to a delay in the rejoining of induced breaks. 3-Aminobenzamide increases the net break frequency that results from a dynamic balance between excision and ligation. This balance appears to be regulated at the ligation step by adenosine diphosphate ribosylation, which is rapidly altered by addition or removal of 3-aminobenzamide. The rapidity with which strand break frequencies change in the presence of 3-aminobenzamide implies that individual strand breaks resulting from excision at any time after exposure have a lifetime of no more than about 30 min in the cell.
TL;DR: The lack of removal of CT as well as TT observed in xeroderma pigmentosum fibroblasts indicates that the repair deficiency in these cells affects the repair of both classes of dimers.
Abstract: The formation and excision of 313-nm light-induced cyclobutane-type pyrimidine photodimers were determined in confluent cultures of human fibroblasts. A new method was developed for the resolution and determination of cytosine-thymine (CT) and thymine-thymine dimers (TT) by using sodium borohydride reduction and high-pressure liquid chromatography. This assay can detect as little as 1.8 TT or 5.6 CT per 10(8) daltons, levels induced in monolayers of human skin fibroblasts by doses of 1 and 2 kJ m-2 of 313-nm light, respectively. CT formation was 20% more efficient than TT formation in the physiological dose range of 2.25-15 k m-2 at 37 degrees C. Normal fibroblasts removed 61% TT within the first 8 h of incubation following a dose of 5.5 kJ m-2. CT was removed approximately twice as efficiently as TT during the same time period following exposure to 10 kJ m-2. The lack of removal of CT as well as TT observed in xeroderma pigmentosum fibroblasts indicates that the repair deficiency in these cells affects the repair of both classes of dimers.
TL;DR: The rapid increase in cellular deoxynucleoside triphosphate (dNTP) concentrations in Chinese Hamster cell line V79 after exposure to known mutagens may reflect the existence of imbalances in dNTP pools at the DNA replication fork.
TL;DR: These studies suggest that coal tars combined with suberythemogenic UVB therapy is a practical alternative (to more aggressiveUVB therapy without coal tar) which reduces the UVB exposure to the patient.
Abstract: Recent studies have questioned the therapeutic value of coal tar versus ultraviolet (UV) radiation and their relative necessity in phototherapy for psoriasis. In this investigation, different aspects of tar phototherapy have been studied in single-blind bilateral paired comparison studies. The effects of 1% crude coal tar were compared with those of petrolatum in conjunction with erythemogenic and suberythemogenic doses of ultraviolet light (UVB) using a FS72 sunlamp tubed cabinet. Crude coal tar was clinically superior to petrolatum with suberythemogenic ultraviolet. With the erythemogenic UVB, petrolatum was equal in efficacy to crude coal tar. Suberythemogenic UVB was also used adjunctively to compare the effects of a 5% concentration of a tar extract in an oil base to 5% crude coal tar in petrolatum or the oil base without tar. The tar extract in oil plus suberythemogenic UVB produced significantly more rapid improvement than the oil base plus UVB. The direct bilateral comparison of equal concentrations of tar extract in oil base versus crude coal tar in petrolatum in a suberythemogenic UV photo regimen revealed no statistical differences between treatments. In a study comparing tar extract in oil and the oil base without ultraviolet radiation, the tar extract in oil side responded more rapidly. This demonstrates a direct effect of tar alone in therapy. We have also studied the effects of erythemogenic and suberythemogenic UVB with and without tar extract in oil in the hairless mouse epidermal deoxyribonucleic acid (DNA) synthesis suppression assay. It was found that erythemogenic dosages of UVB produced near maximal inhibition of DNA synthesis with or without coal tars. Suberythemogenic dosages of UVB produced submaximal suppression of DNA synthesis that was enhanced by adjunctive coal tar but not by vehicle, findings which are consistent with the above clinical results. These studies suggest that coal tars combined with suberythemogenic UVB therapy is a practical alternative (to more aggressive UVB therapy without coal tar) which reduces the UVB exposure to the patient. (J AM ACAD DERMATOL 8:781-789, 1983.)
TL;DR: The concomitant increase and decrease of the ligase activity with the activities of the lyase and the dimethylallyltransferase, as well as its similar response to elicitor concentrations, suggest that CoA esters of cinnamic acids play a role in the biosynthesis of furanocoumarins.
Abstract: Parsley cell cultures produce linear furanocoumarins and the linear benzodipyrandione, graveolone, in response to treatment with an elicitor from either Phytophthora megasperma or Alternaria carthami. Activities of enzymes involved in general phenylpropanoid metabolism, phenylalanine ammonia-lyase and 4-coumarate: CoA ligase, as well as of an enzyme involved specifically in furanocoumarin biosynthesis, dimethylallyl diphosphate: umbelliferone dimethylallyltransferase, were monitored over several days after treatment with A. carthami elicitor. In addition, the activities of chalcone synthase, an enzyme involved in flavonoid formation, and of glucose-6-phosphate: NADP 1-oxidoreductase were also monitored. The lyase and the ligase activities increased steadily for 48 h and the dimethylallyltransferase activity for 54 h, while the synthase activity was not altered and the oxidoreductase activity decreased gradually. In some experiments, phenylalanine ammonia-lyase activity reached a maximum value of 250 mukat/kg, twice the maximal activity observed previously in parsley cells after treatment with either ultraviolet light or an elicitor preparation from P. megasperma. In crude extracts, phenylalanine ammonia-lyase activity was shown to be inhibited by unidentified small-molecular-weight compounds which were formed in proportion to the elicitor treatment. While phenylalanine ammonia-lyase and dimethylallyl diphosphate: umbelliferone dimethylallyltransferase are known to be required for furanocoumarin biosynthesis, the involvement of 4-coumarate: CoA ligase is as yet unclear. The concomitant increase and decrease of the ligase activity with the activities of the lyase and the dimethylallyltransferase, as well as its similar response to elicitor concentrations, suggest that CoA esters of cinnamic acids play a role in the biosynthesis of furanocoumarins.
Patent•
11 Feb 1983TL;DR: In this article, a process for curing a coating on a substrate, which coating has a thickness of about 0.1 mil to about 10 mils, with ultraviolet light comprising the following steps, including applying a coating to the substrate, said coating having a viscosity, as applied, of at least about 50 centipoises.
Abstract: In a process for curing a coating on a substrate, which coating has a thickness of about 0.1 mil to about 10 mils, with ultraviolet light comprising the following steps; (a) applying a coating, which is curable with ultraviolet light, to the substrate, said coating having a viscosity, as applied, of at least about 50 centipoises; (b) exposing the coated substrate to ultraviolet light having wavelengths in the range of about 1800 Angstroms to about 2750 Angstroms in an inert atmosphere for a period of time sufficient to initiate texturing at the surface of the coating; (c) maintaining the coated substrate from step (b) in a space essentially devoid of ultraviolet light for a period of time sufficient for the surface of the coating to texture; and (d) exposing the coated substrate from step (c) to ultraviolet light having wavelengths in the range of about 1800 to about 4000 Angstroms in an inert atmosphere or air until the coating is essentially cured, the improvement comprising, after step (a) and prior to step (b), increasing the viscosity of the coating by exposing the coating to ultraviolet light, said viscosity being increased to a viscosity no higher than that at which the coating is capable of being textured in steps (b) and (c), above.
TL;DR: A novel three-directional thin layer chromatography (TLC) method is reported by which all the polar and neutral lipids are isolated on a single TLC plate, which lends itself to qualitative and quantitative analyses of total lipids.
Abstract: A novel three-directional thin layer chromatography (TLC) method is reported by which all the polar and neutral lipids are isolated on a single TLC plate. Following resolution of the phospholipids by two-directional TLC, lipids are visualized by ultraviolet light after spraying with 2′,7′-dichloro-fluorescein. A line is drawn across the plate, parallel to the second direction of development, separating the resolved phospholipids and the neutral lipids concentrated along the solvent front. The TLC plate is then chromatographed in the reverse direction of the second development to resolve the neutral lipids. By exposing the lipids to HCl fumes after the first development, the plasmalogen content of the lipids may also be determined. This new technique is rapid and lends itself to qualitative and quantitative analyses of total lipids.