Biostimulation of HeLa cells by low-intensity visible light

Summary The action spectra of low-intensity light in the range from 300 to 900 nm on the synthesis rate of nucleic acids in the culture of HeLa cells has been measured. The synthesis of DNA and RNA is stimulated in several spectral intervals with maxima nearby 400, 630, 680, 760 and 820 nm. The stimulation effect is very sensitive to the irradiation duration (light intensity) at a fixed dose. The dose that causes the maximal stimulation is approximately 10 times smaller in the near-UV blue region than in red-IR region.

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Riassunto Si è misurato lo spettro d’azione della luce a bassa intensità nell’intervallo da 300 a 900 nm sul tasso di sintesi degli acidi nucleici in culture di cellule HeLa. La sintesi di DNA ed RNA è stimolata in parecchi intervalli spetrali con massimi vicino a 400, 630, 680, 760 e 820 nm. L’effetto di stimolazione è molto sensibile alla durata d’irradiazione (intensità della luce) ad una dose fissa. La dose che causa la stimolazione massima è approssimativamente dieci volte piú piccola nella regione blu dell’ultravioletto vicino che nella regione del rosso-infrarosso.

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Резюме Измерен спектр действия низкоинтенсивного света в диапазоне (300⋎900) нм на скорость синтеза нуклеиновых кислот в культуре клеток HeLa 1.5 часа после облучения. Синтез ДНК и РНК стимулируется в несколбких спектральных интервалах с максимумами вблизи 400, 630, 680, 760 и 820 нм. Эффект стимуляции очень чувствителен к продолжительности облуения (интенсивности света) при фиксированной дозе. Доза, при которой наблюдается максимальная стимудяция, в несколько ваз меньше в ближнеи УФ-синей области с максимумом около 400 нм.

     

Stimulation of E. coli growth by laser and incoherent red light

Summary The effect of low-intensity He−Ne laser radiation (λ=632.8 nm) and incoherent red light on DNA synthesis and cell division in Escherichia coli has been studied. It has been shown that the radiations of He−Ne laser (λ=632.8 nm) and filament lamp (λ=(631±4) nm) stimulate DNA synthesis and cell growth at doses of 10³ to 10⁴ J/m². The highest level of DNA synthesis is observed 10 min after irradiation and the difference in the numbers of irradiated and control cells is maximum 1 or 2 h after irradiation. The action spectrum of visible light on the growth rate of E. coli cells (from 560 nm to 640 nm) has been measured. The action spectrum has its maximum at (620±7) nm.

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Riassunto Si è studiato l'effetto della radiazione laser He−Ne a bassa intensità e della luce rossa incoerente sulla sintesi del DNA e sulla divisione della cellula in Escherichia coli. Si è mostrato che le radiazioni del laser He−Ne (λ=632.8 nm) e della lampada con filamento (λ=(631±4) nm) stimolano la sintesi del DNA e la crescita cellulare a dose di (10³⋎10⁴) J/m². Il piú alto livello di sintesi del DNA è osservato 10 min dopo l'irradiazione e la differenza nei numeri di cellule irradiate e di controllo è massima 1 o 2 ore dopo irradiazione. Si è misurato lo spettro d'azione della luce visibile sul rapporto di crescita delle cellule di E. coli (da 560 nm a 640 nm). Lo spettro d'azione ha il suo massimo a (620±7) nm.

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Резюме Изучалось влияние низконтенсивного излучения He−Ne лазэра (λ=632.8 нм) и некогерентного красного света на синтез ДНК и клеточное деление в клэтках Escherichia coli. Показано, что как излучение He−Ne лазера, так и лампьи накаливания (λ=(631±4) нм) стимулирует синтез ДНК и клетпчное леление в дозах (10⁻²⋎10⁻³) Джм². Наиболее вьисокий уровень синтеза ДНК наблюлаеттся чурез 10 минут после облучения, скорость клеточногхого делэния максимальна через (1⋎2) часа после облучения. Измерен спектр действия видимого света на скрость деления клеток E. coli от λ=560 нм до λ=640 нм. Спектр действия имеет максимум при (620±7) нм.

     

Multiple infrared photon absorption in OsO4

Multiple ir photon absorption spectra (MPAS) of OsO₄ are obtained in the range of energy fluencies from 3·10⁻² to 1.26 J/cm². A possible interpretation of MPAS is given on the basis of weak forbidden rovibrational transitions. The stepwise character of the absorption on the laser energy fluence is observed.     

Spectral and luminescent study of reduced forms of Pd-octaethylporphin

It is shown by electron absorption spectroscopy methods that the reduction of Pd-octaethylporphin does not touch the unfilled d _x ²-_y ² orbitals of metal. In the reduction products (mono-and dianions), excess electrons are distributed on the lowest vacant molecular e _g (π*) orbital of the ligand. This does not contradict the results of the quantum-chemical calculation of electronic states of neutral Pd-porphyrins by the extended Hückel method that are presented in the literature. Differences in electronic absorption spectra of π-anions of Pd and Zn complexes are attributed to the distortion of the plane geometry of the tetrapyrrole skeleton due to the displacement of the Pd(II) ion from the macrocycle plane. Mono-and dianions of their Pd complex lose the ability to be luminescent. The emissive capacity is reconstructed in the product of π-dianion protonation, which is called phlorin-anion (π-monoanion of Pd-octaethylporphin phlorin). As the temperature is decreased from room temperature to 77 K, the fluorescence spectrum of this product becomes narrower, its peak shifts to the blue region, and the quantum yield of luminescence increases. Specific features of the spectral properties of phlorin-anion are described by conformational changes in the excited state. Phlorin-anion was found to quench luminescence of neutral Pd-octaethylporphin molecules at room temperature.     

Biostimulation of HeLa cells by low-intensity visible light

Summary A culture of HeLa cells was subjected to concurrent and consecutive dichromatic irradiation with visible light of various wavelengths. Consecutive dichromatic irradiation in the sequence 760 nm+633 nm was found to stimulate the synthesis of DNA in the cells and that in the sequence 633 nm+760 nm to inhibit it. These effects reached their maxima when the time interval between the successive irradiation events came to (1⋎3) min. On the strength of these data it is supposed that in HeLa cells there may exist a photochromic, photoreversible pigment similar to photochrome. Based on the results of dichromatic irradiation with blue and red light, flavoproteins are being discussed as likely photoreceptors.

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Una cultura di cellule HeLa è stata sottoposta ad irradiazione dicromatica concomitante e consecutiva con luce visibile di varie lunghezze d'onda. Si è trovato che l'irradiazione dicromatica consecutiva nella sequenza 760 nm+633nm stimola la sintesi del DNA nelle cellule e quella nella sequenza 633 nm+760 nm la inibisce. Questi effetti raggiungono i valori massimi quando l'intervallo di tempo tra irradiazioni successive arriva a (1⋎3) min. Sulla base di questi dati si suppone che nelle cellule HeLa possa esistere un pigmento fotocromatico fotoreversibile simile al fotocromo. In base a questi risultati di radiazione dicromatico con luce blu e rossa, le flavoproteine sono discusse come fotorecettori similari.

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Резюме Проведено одновременное и последовательное дихромное облучение клеток НеЛа различными длинами волн видимой области спектра. Скорость синтеза ДНК стимулируется при последовательном облучении (760+633) нм и инлибирыется при последовательности (633+760) нм. Эффекты являются максимальными когда интервал между лблучениями составляет (1⋎3) мин. На основе зтих данных предполагается существование в клетках ХеЛа фотохромното фотообратимого питмента типа фитохрома. На основе данных о дихромном облученим и красным светом в качестве возможных фоторецепторов обсуждаются флавпротеиды.

     

2-D straw detectors with high rate capability

Precise measurement of straw axial coordinate (along the anode wire) with accuracy compatible with straw radial coordinate determination by drift time measurement and increase of straw detector rate capability by using straw cathode readout instead of anode readout are presented.     

Resonance excitation of C2H4-molecule luminescence by pulsed high-pressure continously tunable CO2 laser

The visible luminescence of ethylene in a focused 10⁹W/cm² continously frequency-tuned field of a high-pressure CO₂ laser was investigated. Q-branch excitation resonance was observed width of 10 cm^-1. No direct correlation between detailed rotational structure and intensity of luminescence was revealed.     

Oxidation of bicyclic monoterpene ketones with Caro’s acid

Previously unknown seven-membered lactones, (1R,1??R,5S,5??S)-5,5??-oxybis(1,8,8-trimethyl-2-oxabicyclo[3.2.1]octan-3-one), 2,2-dimethyl-1,6-dioxaspiro[2.6]nonan-7-one, 4-(1-hydroxy-1-methylethyl)-7-methyloxepan-2-one, and (4R,4??R,7S,7??S)-4,4??-[oxybis(propane-2,2-diyl)]bis(7-methyloxepan-2-one), were synthesized by the Baeyer-Villiger reaction using Caro??s acid as a result of oxidative and skeletal transformations of bicyclic monoterpene ketones, (+)-camphor, (+)-nopinone, and (?)-isocaranone.