Short-wavelength Ultraviolet Light Research Articles

The sensitivity of opiate receptors and ligands to short wavelength ultraviolet light

The sensitivity of the opiate receptor, opiates and opioid ligands to ultraviolet light has been examined with the view of using this property to aid in characterizing the receptor. It is demonstrated that the opiate receptor is very sensitive to short wavelength ultraviolet light which causes rapid destruction of opiate binding activity. It is also shown that tritiated and cold opiate ligands are sensitive to light of this wavelength and when the receptor and opiate ligands are irradiated together, irreversible binding occurs. Along with the sensitivity of the receptor system to proteases and phospholipase the photosensitivity will aid in receptor isolation as well as in development of specific photoaffinity labels.

Thin Layer Chromatography Combined with Color Spot Test Reactions for Preliminary Identification of Papaveraceous Alkaloids

Abstract Thin layer chromatography (TLC) and color spot test reagents (CSTR) were used consecutively to identify isolated papaveraceous alkaloids. Fourteen alkaloid standards were spotted on fluorescent and nonfluorescent silica gel G TLC plates and developed with 3 solvent systems. Spots were evaluated by appearance under daylight, appearance under short wavelength ultraviolet light, color developed by 2 spray reagents, and migration. Eighteen crystalline alkaloids were tested on spot plates with Frohde, Ferreira, Marquis plus oxidant, Mecke, and ferric oxidizing reagents. Colors developed were evaluated as a function of time. Color names were standardized by comparison with color plates from the Centroid Color Charts issued by the Intersociety Color Council of the National Bureau of Standards. TLC separation followed by CSTR is a useful analytical procedure for preliminary identification of alkaloids extracted from tissues of papaveraceae.

Phytoalexin production by high- and low-coumarin cultivars of Melilotus alba and Melilotus officinalis

The isoflavonoid phytoalexin medicarpin has been found to accumulate in leaflets of high- and low-coumarin cultivars of Melilotus alba and Melilotus officinalis following inoculation with the fungus Helminthosporium carbonum. Little or no medicarpin was isolated from leaflets treated with deionised water. Medicarpin was also produced when leaflets were irradiated with short-wavelength ultraviolet light. Elimination of the high-coumarin character from sweet clover cultivars does not appear to affect phytoalexin production, and in consequence, low-coumarin varieties should not be more susceptible to fungal colonisation than their high-coumarin counterparts.

The synthesis and biological properties of 8-azido-N 6-benzyladenine, a potential photoaffinity reagent for cytokinin

A cytokinin photoaffinity reagent, 8-azido-N (6)-benzyladenine (8N3BA), was synthesized from 8-bromoadenosine via azide replacement, benzylation at N-1, rearrangement to the N-6-benzyl derivative and acid hydrolysis. The compound thus obtained was found to have full cytokinin activity in the moss and tobacco cell-suspension bioassays. Photolysis of 8N3BA was accomplished with long and short-wavelength ultraviolet light and produced compounds which had very little or no biological activity in the two bioassays. In-vivo photolysis of 8N3BA caused loss of the cytokinin activity of this compound in moss protonemata. This result was similar to earlier ones where the biological response of moss protonemata to benzyladenine was reversed following removal of the hormone by a short rinse with water.

The Covering Response to Surge, Sunlight, and Ultraviolet Light in Lytechinus Anamesus (Echinoidea)

Examination of the covering reaction (masking or heaping with shells) of Lytechinus anamesus in response to ultraviolet irradiation, sunlight, and surge suggests that most previous hypotheses explaining this reaction are inadequate or incomplete. Shaded L. anamesus initially reacts to short wavelength ultraviolet light (254 nm) with a fairly strong masking response, which is followed by death after an exposure of several days. Long wavelength ultraviolet light (360 mm) elicits moderate covering, while the nonirradiated controls rarely covered. These responses to ultraviolet light are probably artifacts, as L. anamesus and other sea urchins are seldom exposed to that factor in nature. There is a strong and immediate covering response to direct sunlight. Application of surge induces a cover response nearly equal to that of sunlight, regardless of light conditions. The intensity of covering during periods of surge appears to increase during the exposure period. Cessation of surge results in a rapid reduction in covering and a marked increase in movement. We suggest that covering is important in increasing the stability of this echinoid during periods of increased surge by effectively increasing its specific density, reducing its surface area, and changing the configuration it presents to surge forces. Sunlight intensity may be used as a cue that indicates directly the risk of displacement by surge action.

The efficacy of escalol 506 in two topical bases in preventing erythema from artificial ultra-violet light.

Two new sun-screen preparations containing 2.5% of escalol 506 in a hydrophilic base and a petrolatum base were shown to provide effective protection against short wavelength ultra-violet light.

The Chromatographic Separation of Mixtures of Benzodiazepine Drugs

Rapid separation of mixtures of benzodiazepine drugs was achieved using a thin-layer system based on alumina, complemented by a silica gel loaded paper system. Location of the spots was by short-wavelength ultraviolet light and acidified potassium iodoplatinate. The compounds examined were Chlordiazepoxide, Diazepam, Nitrazepam, Oxazepam, Bromazepam, Medazepam and Dibenzepine. Their behaviour to ultraviolet light of wavelength 254nm and 350nm under neutral, acid and alkaline conditions was examined in the form of spot tests on filter paper.

Protection of skin from germicidal ultraviolet radiation in the operating room by topical chemicals.

MERCURY-arc lamps emitting short-wavelength ultraviolet light (254 mμ) are widely used for their microbicidal effect in tissue-culture laboratories, food-preparation areas, hospital ventilation systems and operating rooms.1 , 2 Their use in operating rooms, however, has been somewhat limited because of the known erythema and desquamation; hyperpigmentation can occur when human skin is exposed to these wavelengths.3 , 4 To avoid these damaging effects on the skin, as well as a potential carcinogen effect of the radiation,5 operating-room personnel must wear cumbersome gear that leaves no cutaneous surface exposed. Commercially available lotions designed to minimize or block the sunburn reaction and permit tanning without discomfort . . .

ESR-Studies of Normal and 5-Bromouracil-Substituted DNA of Bacillus subtilis after Irradiation with Ultraviolet Light

Electron spin resonance signals are induced, at 77°K and in the presence of water, in B. subtilis DNA in which about 70% of the thymine has been replaced by 5-bromouracil, either by short wavelength ultraviolet light (UV) (2400-4000 A) or by long wavelength UV (3200-4000 A). In DNA not containing bromouracil, short wavelength UV induces signals; long wavelength UV produces no detectable signal, indicating a rate of production at least ten times lower than in DNA containing bromouracil. Bromouracil in the DNA suppresses the thymine ESR spectrum to a greater extent than the degree of thymine replacement. The signal induced in DNA containing bromouracil is the same with both ultraviolet radiations, a triplet with g = 2.0023 and an overall splitting of 46 G and a superposed singlet, quite different from that for irradiated bromodeoxyuridine, or a nucleoside mixture. It is unchanged by substituting D2 O for H2 O. The probable location of the radical responsible for the triplet is on the sugar. In the presence ...

Ultraviolet-induced changes in the infectivity of Agrobacterium tumefaciens.

The infectivity of Agrobacterium tumefaciens strain B6 irradiated with short-wavelength ultraviolet light was followed as a function of dose. Previously reported enhancements of B6 infectivity by ultraviolet irradiation, in samples inoculated after 1.75 hr of dark incubation at 27 C, or immediately following irradiation, were found to occur most frequently after losses in cell viability of 60% and of 90% or more, respectively. Changes in colony-forming ability and tumor-initiating ability with increasing dose showed no obvious correlation until the maximal infectivity promotion of samples inoculated immediately after irradiation was reached. Thereafter, both bacterial responses typically decreased in parallel. With low dose rates, infectivity promotions were obtained with less than 10% loss in cell viability. Data for tumor appearance and tumor growth resulting from inoculations with irradiated cultures showed no significant differences from controls, nor did the age of the bacterial culture or age of the host plant influence the response. The infectivity promotion appears to result from an increase in the proportion of viable cells that will subsequently initiate tumors. The characteristics of this ultraviolet infectivity promotion are shown to be most similar to those found in prophage and bacteriocin induction.

Increased sensitivity in the detection of adenine and pyridine nucleotides by exposure to ultraviolet light at low temperature.

IN 1957 Szent-Gyorgyi described a procedure for the enhancement of fluorescence of compounds spotted on paper by cooling with solid carbon dioxide or liquid nitrogen1. Gordon and South have applied this procedure to the action of aromatic acids and other aromatic ring-containing compounds2. We have found that by observing absorption, fluorescence and delayed fluorescence on exposure to long and short wave-length ultra-violet light, NAD+ and NADH can be distinguished from each other and from ADP and ATP.

PHOTOREVERSIBLE ULTRAVIOLET ENHANCEMENT OF INFECTIVITY IN AGROBACTERIUM TUMEFACIENS.

Heberlein, Gary T. (Northwestern University, Evanston, Ill.), and James A. Lippincott. Photoreversible ultraviolet enhancement of infectivity in Agrobacterium tumefaciens. J. Bacteriol. 89:1511-1514. 1965.-Irradiation of a virulent strain of Agrobacterium tumefaciens with short-wavelength ultraviolet light, which reduces viability 50 to 90%, increases its infectivity as measured by the number of tumors initiated per viable bacterial cell on primary pinto bean leaves. A dark treatment of 1.5 to 2 hr between irradiation and inoculation results in a further increase in specific infectivity of as much as fourfold. This increase in infectivity is inhibited by white fluorescent light and light of 402 mmu, but only slightly by 549- or 619-mmu light. These results imply that some change in the deoxyribonucleic acid of the bacterium is responsible for this effect.

The Quantitative Determination of Mixed Sulfonamides by Paper Chromatography

Abstract A simplified quantitative procedure for the determination of mixed sulfonamides in pharmaceuticals is presented. The components are resolved by paper chromatography and located by their fluorescence under short wavelength ultraviolet light. They are then eluted and determined colorimetrically by a revised Bratton-Marshall technique. Total time of analysis is less than 4 hours. Recoveries averaged 98.8% with a range of 95.7 to 103.4%. Mean deviation from the average was 1.4%.

The effect of ultraviolet light on photophosphorylation and the hill reaction

Abstract 1. 1. Photophosphorylation and Hill-reaction activity of swiss-chard chloroplasts or chloroplast fragments were decreased by irradiation with short-wavelength ultraviolet light. 2. 2. Photophosphorylation was more resistant to irradiation than the Hill reaction. 3. 3. The presence of ascorbate during irradiation prevented the decrease in Hill reaction and photophosphorylative activity. Protection was more pronounced for the Hill reaction than for photophosphorylative activity. Compounds containing SH-groups could not replace ascorbate; it is suggested that ascorbate protects mostly by reducing the effective ultraviolet intensity, and in addition by exerting a specific effect on the chloroplasts themselves. 4. 4. By ultraviolet irradiation, it was possible to obtain chloroplast preparations which had lost the ability to perform the Hill reaction, but still possessed high photophosphorylative activity. Such preparations may be useful in further research. 5. 5. The endogeneous plastoquinone of chloroplasts was shown to be destroyed by irradiation. 6. 6. The activity of irradiated chloroplasts was stimulated by the addition of plastoquinone. However, a similar stimulation was obtained on addition of plastoquinone to non-irradiated chloroplasts.

OPTICAL ROTATORY DISPERSION OF SOME DEHYDROGENASES*

SummaryThe optical rotatory dispersion of solutions of alcohol dehydrogenase (AD), glyceralde‐hyde‐3‐phosphate dehydrogenase (GAPD), glutamic dehydrogenase (GAD), and malic dehydrogenase (MD) was investigated. The b, values of the native dehydrogenases were found to be between ‐170 and ‐450. GAD and MD were studied also with the short wave length ultraviolet light, and they both displayed strong Cotton effects at 230–245 mµ. The solutions of native GAD were found to be dextrorotatory, however, they became levorotatory on denaturation with alkali, urea, or sodium decyl sulfate. According to the rotatory dispersion data, the dehydrogenases belong to the α‐helical globular proteins, although it seems premature to make quantitative estimates of the a‐helix content from the rotatory dispersion data alone.

Changes Produced by Ultraviolet Light in the Presence and in the Absence of Oxygen on the Physical Chemical Properties of Deoxyribonucleic Acid

Dilute solutions of DNA were irradiated with a mercury lamp in a quartz envelope that allowed radiations of low wavelength to penetrate, and with a filtered lamp with which the effects were due solely to light of 254-m mu wavelength. In the absence of oxygen, irradiation with the Vycor lamp reduced the viscosity and radius of gyration of the DNA. Initially there was no effect on the molecular weight, which fell only after a threshold period. Evidence from the absorption spectrum of the irradiated DNA and its stability at elevated temperatures suggests that the primary effect of 254-m mu light is to disrupt hydrogen bonds and thereby make the molecule more flexible so that it assumes a more coiled configuration in solution. In the presence of dissolved oxygen the rate of coiling by 254-m mu light is increased and main-chain scission (estimated from molecular weight changes) occurs immediately. With the unfiltered ultraviolet light both coiling and main-chain scission occur in the absence of oxygen. In its presence the number of breaks is greatly enhanced. The oxygen effect is probably due to the addition of oxygen to activated DNA to give a peroxide which is decomposed with the release of OHmore » radicals. Hydroxyl radicals were shown to produce main-chain breaks but did not give rise to coiling. Ozone produced by short-wavelength ultraviolet light produces main-chain breaks relatively ineffectively. Decomposition products of ozone are probably the principal degradative agents when DNA is irradiated with the unfiltered lamp. Glutathione, dimethylaniline, and glucose (in relatively high concentrations) protect DNA against the effect of ultraviolet light in the presence of oxygen but not in the absence of oxygen. (auth)« less

Ultraviolet Irradiation and Absorptiometric Methods for the Determination of Diethylstilbestrol in Tablets

The present official method for the determination of diethylstilbestrol is not specific, and incomplete extraction of active material from small dosage tablets is often encountered. To circumvent these difficulties, two new methods of assay have been developed. The procedures depend on photochemical changes which diethylstilbestrol undergoes when it is irradiated with short wavelength ultraviolet light and on the reproducible shift of the ultraviolet absorption spectrum of diethylstilbestrol in acid and in alkaline solution. Apparatus for the irradiation method includes a suitable strong ultraviolet light source and a spectrophotometer capable of measuring visible light absorption, while the ultraviolet absorptiometric method requires a spectrophotometer operating in the ultraviolet region. Interferences in the irradiation procedure are primarily inhibitory in nature while those in the UV absorptiometric method are those compounds which exhibit a shift in absorption spectrum in the 280 mμ range in acid and alkaline solution. The nature of the pigment produced by irradiation is not known.

Soft Soda Glass to Transmit Bactericidal Radiation

Small amounts of iron, titanium, sulphur and iodine have a marked effect on the transmission of short wavelength ultra-violet light. Provided due care is taken to keep these impurities to a minimum and to melt under suitable (reducing) conditions, soft glasses of a variety of compositions can be made having excellent transmission at 2 537 A.

The Assignment of Quantum Numbers for Electrons in Molecules. I

The Assignment of Quantum Numbers for Electrons in Molecules. I