Showing papers on "Ultraviolet light published in 1978"

Characterization of a new photoaffinity derivative of ouabain: labeling of the large polypeptide and of a proteolipid component of the Na, K-ATPase.

Abstract: We have synthesized 2-nitro-5-azidobenzoyl (NAB) derivatives of ouabain as photoaffinity labels of the cardiac glyocoside binding site of Na, K-ATPase. [3HzNAB-ouabain was found to bind to the same number of sites on Na, K-ATPase (purified from pig kidney outer medulla) as ouabain (1.9 nmol/mg), with approximately the same affinity (Kk(ouabain)/Kd(NAB-ouabain) congruent to 1.6), and ouabain was fully competitive uith NAB-ouabain at these sites. NAB-ouabain binding and inhibition were reversible in the dark, but on exposure to ultraviolet light (310-370 nm) 30-40% of the binding and ihibition became irreversible; this binding was shown to be covalent by stability to trichloroacetic acid, organic solvents, and heat denaturation. Covalent labeling was prevented by photolysis of NAB-ouabain prior to the experiment, or by prior incubation of the enzyme with ouabain. On sodium dodecyl suffate-polyacrylamide gels of labeled Na,K-ATPase, about half of the covalently bound [3H]NAB-ouabain migrated with the large polypeptide (molecular weight congruent to 95 000), and half migrated with a small polypeptide (molecular weight congruent to 12 000); noncovalently bound NAB-ouabain (60-70% of total label) ran with the tracking dye. A similar labeling pattern was obtained utilizing NaI microsomes prepared from pig kidney outer medulla. The small polypeptide was characterized as an acidic proteolipid by extractability into acid chloroform/methanol; labeling of this component by NAB-ouabain is the first demonstration that it is directly associated with the Na,K-ATPase. The results of our characterization of NAB-ouabain show that it has the required specificity, covalency, and efficiency of labeling for application in structural studies of Na,K-ATPase subunit interactions.

Metastatic Heterogeneity of Cells from an Ultraviolet Light-induced Murine Fibrosarcoma of Recent Origin

Abstract: We wished to determine whether cells within a murine tumor of recent origin vary in their metastatic potential. A fibrosarcoma induced in a C3H- mouse by chronic ultraviolet irradiation was established in tissue culture, and 21 clones were produced from the parent line. For determination of whether cells with different metastatic potential preexisted in the population of whether the process of metastasis resulted from the random survival of cells with equal metastatic capabilities, the parent line and the 21 clones were tested for metastatic behavior in syngeneic mice. Three different in vivo tests were used: (a) mice were given injections of 105 tumor cells i.v., they were killed 18 days later, and the tumor colonies in the lungs were counted; (b) mice were given s.c. injections of 105 tumor cells and examined at death for the presence of spontaneous metastases; (c) mice were given i.v. injections of 105 tumor cells and autopsied at death. The time of death was recorded, and the number and site of metastases were determined. The clones varied greatly in their ability to grow and metastasize after s.c. or i.v. inoculation. The three tests gave similar results in that clones judged to be of high or low metastatic potential in one test usually exhibited the same behavior in the other two tests. We conclude that the parent tumor is heterogeneous and that cells with widely different metastatic potential preexist in the parental population.

Toxicity of a furanocoumarin to armyworms: a case of biosynthetic escape from insect herbivores.

Abstract: When the linear furanocoumarin xanthotoxin, found in many plants of the families Rutaceae and Umbelliferae, was administered to larvae of Spodoptera eridania, a generalist insect herbivore, it displayed toxic properties lacking in its biosynthetic precursor umbelliferone. Reduced toxicity observed in the absence of ultraviolet light is consistent with the known mechanism of photoinactivation of DNA by furanocoumarins through ultraviolet-catalyzed cross-linkage of strands. Thus, the ability of a plant to convert umbelliferone to linear furanocoumarins appears to confer broader protection against insect herbivores.

Pressure sensitive adhesives

Abstract: A pressure sensitive adhesive is formed from a composition comprising mono-functional unsaturated acrylate ester monomer, essentially saturated tackifying resin polymer dissolved in the acrylate ester, non-crystallizing elastomeric material also dissolved in the acrylate ester, and an initiator responsive to ultraviolet light or other penetrating radiation such as electron beam, gamma or X-ray radiation The composition is cured by subjection to ultraviolet light or other radiation, which causes the initiator to induce polymerization of both the acrylate ester and the non-crystallizing elastomeric material, apparently with co-polymerization therebetween

Skin color and nutrient photolysis: an evolutionary hypothesis

Abstract: Human populations native to areas of intense sunlight tend to be heavily melanized. Previous explanations for this relationship have invoked only weak selective pressures. To test the hypothesis that dark pigmentation may protect against photolysis of crucial light-sensitive vitamins and metabolites by ultraviolet light, folate was used as a model. It was found that exposure of human plasma in vitro to simulated strong sunlight causes 30 to 50 percent loss of folate within 60 minutes. Furthermore, light-skinned patients exposed to ultraviolet light for dermatologic disorders have abnormally low serum folate concentrations, suggesting that photolysis may also occur in vivo. Deficiency of folate, which occurs in many marginally nourished populations, causes severe anemia, fetal wastage, frank infertility, and maternal mortality. Prevention of ultraviolet photolysis of folate and other light sensitive nutrients by dark skin may be sufficient explanation for the maintenance of this characteristic in human groups indigenous to regions of intense solar radiation.

Deficient recovery from potentially lethal radiation damage in ataxia telangiectasia and xeroderma pigmentosum

Abstract: THE enhanced survival that occurs when mammalian cells are maintained in a density-inhibited state for a short time after treatment with X rays, ultraviolet light or drugs has been termed potentially lethal damage repair (PLDR)1–3. It is analogous to liquid-holding recovery in bacteria and yeast, and has been studied using a variety of agents in different cell lines3–5 and in malignant tumours6,7. To investigate the relationship between this cellular recovery phenomenon and repair at the molecular level, we have examined PLDR in human diploid cell strains with known molecular repair defects. We report here that xeroderma pigmentosum (XP) skin fibroblasts show no PLDR following ultraviolet light irradiation, whereas ataxia telangiectasia (AT) skin fibroblasts are specifically deficient in PLDR following X-ray irradiation. The results suggest that, as in bacterial cells, this cellular recovery phenomenon does reflect molecular DNA repair—probably the excision repair pathway.

Isolation of an avian erythrocyte protein possessing ADP-ribosyltransferase activity and capable of activating adenylate cyclase

Abstract: An ADP-ribosyltransferase was purified ∼500-fold from the supernatant fraction of turkey erythrocytes. The enzyme hydrolyzed [carbonyl-14C]NAD to ADP-ribose and [carbonyl-14C]nicotinamide at a low rate. Nicotinamide formation from NAD was enhanced by arginine methyl ester > D-arginine ∼ L-arginine > guanidine; lysine, histidine, and citrulline were ineffective. Incubation of [adenine-U-14C]NAD and arginine methyl ester or arginine with the purified enzyme resulted in the formation of new compounds that contained 14C, reacted with ninhydrin, and quenched background fluorescence of thin-layer plates viewed in ultraviolet light. Their mobilities on thin-layer chromatograms were indistinguishable from those of ADP-ribosylarginine methyl ester and ADP-ribosylarginine formed during incubation of choleragen with NAD and arginine methyl ester or arginine, respectively [Moss, J. & Vaughan, M. (1977) J. Biol. Chem. 252, 2455-2457]. The purified transferase also catalyzed the incorporation of label from [adenine-14C]-NAD into lysozyme, histones and polyarginine. When the 14C-labeled lysozyme was incubated with snake venom phosphodiesterase, the radioactivity was released and, on thin-layer chromatograms, exhibited a mobility indistinguishable from that of 5′-AMP, as would be expected of an ADP-ribosylated protein, but not of a poly(ADP-ribosylated) product. The purified transferase activated rat brain adenylate cyclase and, as is the case with choleragen, activation was absolutely dependent on NAD. The presence in the avian erythrocyte of a protein that, like choleragen and Escherichia coli heat-labile enterotoxin, apparently activates adenylate cyclase and possesses ADP-ribosyl transferase activity is consistent with the view that the mechanisms through which the bacterial toxins produce pathology are not entirely foreign to vertebrate cells, at least some of which may possess and employ an analogous mechanism for activation of adenylate cyclase.

Base-specific reactions useful for DNA sequencing: methylene blue – sensitized photooxidation of guanine and osmium tetraoxide modification of thymine

Abstract: Exposure of DNA to methylene blue and visible or ultraviolet light causes guanine-specific modification, and subsequent treatment with piperidine leads to chain cleavage at each guanine residue. Treatment of DNA with osmium tetraoxide in dilute pyridine leads to thymidine-specific modification, and subsequent treatment with piperidine leads to chain cleavage at the modified thymidine residues. Both reactions can be used in conjunction with other base specific modifications described by Maxam and Gilbert (1) for the determination of the nucleotide sequence in DNA.

Estimation of fermentation biomass concentration by measuring culture fluorescence.

Abstract: The fluorescence of a fermentation culture was studied for its application as an estimator of biomass concentration. The measurement was obtained by irradiating the culture with ultraviolet light (366 nm) through a glass window and detecting fluorescent light at the window surface at 460 nm. It was estimated that over one-half of the fluorescent material was intercellular reduced nicotinamide adenine dinucleotide, with the remainder being reduced nicotinamide adenine dinucleotide phosphate and other unidentified intercellular and extracellular fluorophores. The culture fluorescence was found to be a function of biomass concentration, together with environmental factors, which presumably act at the cellular metabolic level to modify intercellular reduced nicotinamide adenine dinucleotide pools (e.g., dissolved oxygen tension, energy substrate concentration, and inhibitors). When these environmental conditions were controlled, a linear relationship was obtained between the log of the biomass concentration and the log of the fluorescence. Under these conditions, this relationship has considerable potential as a method to provide real-time biomass concentration estimates for process control and optimization since the fluorescence data is obtained on line. When environmental conditions are variable, the fluorescence data may be a sensitive index of overall culture activity because of its dependence on intercellular reduced nicotinamide adenine dinucleotide reserves and metabolic rates. This index may provide information about the period of maximum specific productivity for a specific microbial product.

The study of histone--histone associations by chemical cross-linking.

Abstract: Publisher Summary This chapter presents a study of histone–histone associations by chemical cross-linking. Chemical cross-linking can be used to reveal both the pattern and the degree of association of polypeptides in a multisubunit structure. Limited cross-linking results in dimmers that are formed from neighboring polypeptides. Extensive cross-linking gives a series of higher-molecular-weight products, the largest of which comprises the total number of subunits in the structure. Both types of analysis have been applied to the histones with the use of a variety of cross-linking agents, such as formaldehyde, imidoesters, tetranitromethane, ultraviolet light, and dicyclohexylcarbodiimide. The chapter focuses on the imidoesters, whose reaction with proteins is well understood. The procedures for cross-linking with imidoesters are straightforward, and success in their application to histones and chromatin is largely dependent on the resolving power of the methods used to identify the cross-linked products. Fractionation of the histones and cross-linked products is difficult because of their similar charges and molecular weights. In the chapter, cross-linking of histones in chromatin and in free solution is described as well as examples of cross-linking with dimethyl suberimidate are presented.

Method of making high quality plastic lenses

Abstract: A method of making plastic lenses by casting a liquid monomer and a photosensitive catalyst between two transparent optical molds One of the transparent molds having a convex lens on the outer surface to focus ultraviolet light toward the center of the monomer activating the photosensitive catalyst and initiating polymerization in the center of the plastic lens material Polymerizing the monomer to form a solid lens having optical surfaces formed by the transparent molds

Mechanisms of Attachment of Neutrophils to Candida albicans Pseudohyphae in the Absence of Serum, and of Subsequent Damage to Pseudohyphae by Microbicidal Processes of Neutrophils In Vitro

Abstract: Mechanisms were studied that might explain the attachment and damage to Candida albicans pseudohyphae by neutrophils in the absence of serum. Attachment of neutrophils to pseudo hyphae was inhibited by Candida mannans (1-10 mg/ml), but not by mannose, dextran, chitin, conconavalin A, or highly charged polyamino acids. Contact was also inhibited by pretreatment of Candida before incubation with neutrophils with chymotrypsin, but not trypsin or several inhibitors of proteases. Similar results were obtained with pretreatment of neutrophils, except that trypsin was inhibitory. When pseudohyphae were killed with ultraviolet light, proteinpolysaccharide complexes of mol wt <10,000 were released which appeared to bind to the surfaces of neutrophils and inhibit contact between neutrophils and Candida, as well as other fungi. Damage to Candida by neutrophils was inhibited by agents known to act on neutrophil oxidative microbicidal mechanisms, including sodium cyanide, sodium azide, catalase, superoxide dismutase, and 1, 4 diazobicyclo (2, 2, 2) octane, a singlet oxygen quencher. Neutrophils from a patient with chronic granulomatous disease did not damage Candida at all. However, the hydroxyl radical scavengers mannitol and benzoate were not inhibitory. Cationic proteins and lactoferrin also did not appear to play a major role in this system. Low concentrations of lysozyme which did not damage Candida in isotonic buffer solutions damaged pseudohyphae in distilled water. Isolated neutrophil granules damaged pseudohyphae only with added hydrogen peroxide and halide, and damage occurred only with granule fractions known to contain myeloperoxidase. These findings suggest that neutrophils recognized a molecule on the Candida surface which has a chymotrypsin sensitive protein component, and which may be liberated from the cell surface upon death of organism. The neutrophil receptors for Candida appear to be sensitive to trypsin and chymotrypsin. Damage to Candida by neutrophils occurred primarily by oxidative mechanisms, including the production of superoxide and hydrogen peroxide interacting with myeloperoxidase and halide, as well as singlet oxygen, but did not appear to involve hydroxyl radical. Lysozyme might have an accessory role, under some conditions.

Full‐color photosensitive glass

Abstract: New polychromatic (full‐color photosensitive) glasses are described in which the full color spectrum is developed by photochemical precipitation of subcolloidal silver too small to scatter light. The brilliant colors are shown to be due to selective light absorption by randomly oriented silver‐containing particles having controlled anisotropic shapes. The color photographic process and its chemistry are outlined. Controlled anisotropy is due to photo‐silver‐nucleated growth of elongated NaF⋅ (Na,Ag) X pyramidal crystallites, concentration of AgX at the apex, and subsequent photoprecipitation of this silver. Resultant colors are primarily a function of exposure flux (intensity × time) employing ultraviolet light (300 nm). The colors can be semiquantitatively described from electromagnetic theory assuming ellipsoidal metal particles suspended in a transparent dielectric medium. An absorption band moves across the visible spectrum as a function of particle eccentricity. Polychromatic glasses can be made havi...

Apparatus for sanitizing liquids with ultra-violet radiation and ozone

Abstract: Apparatus for contacting contaminated water with ultra-violet light to eliminate potentially harmful organisms as well as to provide air cooling necessary for efficient operation of the UV lamp and simultaneous production of ozone in the apparatus for secondary disinfection of the water, the water after treatment by the ultraviolet light being discharged into a water storage tank, and the irradiated air that contains the ozone being discharged into the tank into contact with the water for carrying out the secondary disinfection.

Photochemical inactivation of DNA and RNA viruses by psoralen derivatives.

Abstract: Summary Western equine encephalitis virus, and RNA virus, and herpes simplex virus type 1, a DNA virus, were efficiently inactivated in less than 1 min by exposure to long-wave ultraviolet light (320 to 380 nm) in the presence of several psoralen derivatives. The psoralen photochemical reaction was chosen for study due to its known specificity for nucleic acids. Neither the light nor any of the drugs alone caused appreciable inactivation. The inactivation kinetics and dependence on light intensity and on different derivatives of psoralen were studied. The high solubility of a new aminomethyl psoralen derivative was found to be advantageous in the photochemical inactivation of the RNA virus, but was not in the case of the more easily inactivated DNA virus. Within its limited solubility range trimethylpsoralen was superior to its aminomethyl derivative on a molar basis for the inactivation of both types of viruses under most of the conditions studied.

Ultraviolet light detection by the homing pigeon

Abstract: HUMANS cannot see the near ultraviolet (UV) wavelengths (320–400 nm) in sunlight. By analogy, it is often assumed that most vertebrates are also UV-blind1. This generalisation has been called into question by recent experimental evidence showing that toads, newts, lizards, and hummingbirds are behaviourally responsive to UV light2–5. We present here evidence suggesting that homing pigeons (Columba livia) are sensitive to UV wavelengths and capable of responding to the intensities of UV light that prevail in nature. Our results were obtained by a cardiac conditioning technique used previously to demonstrate homing pigeon sensitivity to barometric pressure changes, polarised light and infrasound6–10.

Structure and function of the pigeon visual system

Abstract: This comprehensive, up-to-date account of vision in the pigeon begins with a description of the eye, its dimensions, and optical properties. The retina is discussed in considerable detail, with particular attention given to: the distribution of the various cell types within and across the retina, the number and the nature of the oil drops in the cones, the highly developed inner plexiform layer, the response characteristics of the ganglion cells, and the damage to cones caused by exposure to light. Lastly, the three major visual pathways are examined neuroanatomically and electrophysiologically. In the second section, several important issues have been emphasized: the putative differences between frontal and lateral vision, visual sensitivity to both discrete and periodic stimuli at various adaptation levels, polarotaxis in the pigeon, the bipartite spectral sensitivity of its retina, hue and saturation discrimination, sensitivity to ultraviolet light, panoramic acuity, and the detection of movement.

Automatic inventorying system

Abstract: A method and means for automatically inventorying items having coded tags or labels using a character-recognition device, such as a wand scanner, in combination with a system for specially marking the labels when they have been successfully read and recorded by the scanner, which system comprises the use of a photosensitive dye-forming material on the label and an ultraviolet light-producing flash device on the scanner. The flash device is actuated upon the successful completion of a recognition reading and irradiates the label with ultraviolet light which produces a visible and permanent mark on the label.

Induction of UV light tolerance by PUVA in patients with polymorphous light eruption.

Abstract: SUMMARY A tan induced by 8-methoxypsoralen-long wave ultraviolet light has proved an effective photo- protective sunscreen in 5 patients with long wave ultraviolet light-induced polymorphic light eruption.

DNA repair in primary cultures of rat hepatocytes.

Abstract: This report describes a precise quantitative analysis of DNA repair in cultured rat hepatocytes following exposure to ultraviolet light, 2-acetylaminofluorene, and two of its more active derivatives, N -hydroxy-2-acetylaminofluorene and N -acetoxy-2-acetylaminofluorene. Hepatocytes were isolated from young adult male Wistar rats with the collagenase perfusion technique and maintained in short-term monolayer culture on collagen-coated plates in a serum-free modified Waymouth's medium. The nuclear [3H]thymidine ([3H]dThd)-labeling index of control cultures was less than 0.1%, but significant cytoplasmic labeling was evident in autoradiographs. Of the total acid-precipitable radioactivity present in control cultures following exposure to [3H]dThd, 54% of the 3H was found in protein, demonstrating the ability of these nonreplicating hepatocytes to catabolize [3H]dThd and reutilize the labeled metabolites. Ultraviolet light irradiation of the cultured hepatocytes resulted in a dose-dependent increase of [3H]dThd incorporation into DNA. That this represented nuclear DNA repair synthesis was demonstrated by detecting nonsemiconservative DNA synthesis (repair replication) with NaI isopycnic centrifugation and autoradiography. Hydroxyurea (10 and 100 mm) had only a small inhibitory effect, while both 1-β-d-arabinofuranosylcytosine (25 and 100 µm) and ethidium bromide (at 25 µm) dramatically inhibited the ultraviolet light-induced increase in [3H]dThd incorporation. Repair synthesis also occurred in response to treatment of the hepatocytes with 2-acetylaminofluorene, demonstrating their ability to metabolize this prohepatocarcinogen to a form capable of damaging DNA. N -Hydroxy-2-acetylaminofluorene and N -acetoxy-2-acetylaminofluorene were more effective in inducing a repair response. These results represent additional characterization of the primary hepatocyte culture system and demonstrate its potential for studies on mechanisms of carcinogenesis and as a potential screening system for environmental chemicals suspected of being capable of damaging DNA and causing cancer.

Electroluminescent diode and optical fiber assembly

Abstract: An optical fiber and an electroluminescent semiconductor diode are each secured to separate mounting blocks which in turn are secured to each other, either directly or through an additional block, with the optical fiber aligned with the output of the diode. The mounting blocks are secured together by a thin layer of a bonding material which is preferably fast setting so as to prevent or limit relative movement between the mounting blocks which could cause misalignment of the optical fiber and the diode. The bonding material is preferably of the type which is cured when subjected to ultraviolet light, and at least one of the mounting blocks is preferably transparent to the ultraviolet light.

Trioxsalen bath plus UVA effective and safe in the treatment of psoriasis

Abstract: SUMMARY Seventy-four patients with psoriasis were treated using a trioxsalen bath (50 mg/150 1 of water) and long wave ultraviolet light (UVA) given in an ordinary PUVA-cabin. Good or excellent results were observed in 92% of the patients in the initial phase and in 63% during the maintenance treatment. Because of local side-effects the therapy was discontinued in two patients. One of them developed contact hypersensitivity to trioxsalen and the other developed blisters with such low doses of UVA that it was difficult to maintain the proper dose. The therapy was started with 0-28 J/cm2 of UVA and after an average of 18 treatments, when the average dose was 1.70 J/cm2, the patients were moved to maintenance treatment which took place at 1-4 week intervals. The therapy was well tolerated and cosmetically very acceptable. The final tan was even on all but the face, which remained untanned.

Relation between dna repair, chromosome aberrations, and sister chromatid exchanges

Abstract: Ordinary chromosome aberrations and sister chromatid exchanges (SCEs), which are two types of cytogenetic endpoints that are currently being used to determine the effects of mutagens and carcinogens on chromosomes, differ in several aspects. A) Double stranded DNA breaks, which are induced by X Rays, lead to aberrations but not to SCEs. B) Ordinary chromosome aberrations that are induced by ultraviolet light are photoreactivable, whereas we now have found in chick embryo cells that even though thymine dimers are removed by PR light, the yield of UV-induced SCEs is unaffected. C) Aberrations induced by UV or “UV-like,” but not “X-ray-like” mutagens are higher in XP cells than in normal cells, whereas SCEs are higher in XP cells after treatment with all three types of mutagens. D) The aberration yields are related to the amount of excision repair as measured by unscheduled DNA synthesis or repair replication whereas SCE yields are not. E) Aberrations are increased by application of caffeine after treatment with UV light or chemical mutagens but SCEs are not, and in post-replication defective XP variant cells, UV-induced SCE levels are as in normal cells. Taken as a whole these data indicate that although aberrations are dependent upon excision repair and post-replication repair as measured in ordinary experiments, SCEs are not. The lesions that result in SCEs do not seem to be thymine dimers or alkylation products at the N7 position of guanine. Since SCEs are induced by long-lived lesions that disappear with time, minor photoproducts, or alkylation products, that are not measured in excision repair or post-replication repair experiments seem to be the lesions responsible for SCE formation, which is contrary to the findings for chromosome aberrations.

Glucocorticoid Resistance in Murine Lymphoma and Thymoma Lines

Abstract: The thymoma line W7 contains 30,000 dexamethasone-binding sites per cell and gives rise to glucocorticoid-resistant variants at a frequency -9 ; the lymphoma S49 contains one-half that amount of receptor, is resistant to low concentrations of dexamethasone, and gives rise to fully resistant variants at high frequency. These results suggest that S49 is functionally haploid ( r +/- ) for a gene coding for the receptor while W7 appears diploid for that locus ( r +/+ ). Derivatives of the W7 ( r +/+ ) line, selected for resistance to low concentrations of dexamethasone, have the same properties as S49. These putative W79s ( r +/- ) give rise to the same types of receptor variants as S49 and in the same proportion; 80 to 90% are “receptorless” ( r - ) while 10 to 20% are “nuclear transfer defective” ( nt - ). A total of 127 variants resistant to high concentrations of dexamethasone were derived from the W7 ( r +/+ ) line after mutagenesis. All are receptor variants but N -methyl- N ′-nitro- N -nitrosoguanidine and ethyl methanesulfonate induce only 60 to 70% r - variants, confirming the presence of two r + alleles in the parental line. Ultraviolet light induces a higher proportion (87%) of r + variants, as expected from the introduction of breaks and deletions in DNA.

Jet ink process and ink composition fluorescent in ultraviolet light

Abstract: Ink compositions suitable for ink jet printing on metal, plastic, or paper surfaces, the ink characterized by fluorescent properties in ultraviolet light, incorporating, in solution, a resin component, at least one solvent, proportioned to give the ink properties of heat and steam resistance, said inks are colorless in ordinary light and distinctly fluorescent in ultraviolet light so as to render them particularly suitable as a means for marking various materials whereby marking is normally invisible but easily detectable when subjected to ultraviolet illumination According to another of its aspects, this invention is a process for information recording comprising producing a fine jet of liquid, directing a jet of colorless liquid onto a recording medium modulating the density of the applied jet by an electric field in accordance with the information to be recorded, thereby recording said information