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Biomedical subjects

L B Rubin

Publications and source records attributed to L B Rubin.

66 records · Page 4Linked to original sources
PubMedDate not supplied

[Effect of long-wave ultraviolet light (313 nm) on the survivability and respiration of Candida utilis yeasts].

Irradiation of Candida utilis with near-UV (313 nm) was found to inhibit respiration; the degree of the inhibition correlated with the number of killed cells. Irradiation of the yeast mitochondria inhibited the activity of succinate oxidase; the dependence of the inhibition on the dose of near-UV (313 nm) was close to the dose dependence of the photoinhibition of respiration in whole cells. The action spectrum for the inhibition of the activity of succinate oxidase was recorded; it corresponded to the absorption spectrum of ubiquinone isolated from the yeast cells. The data obtained suggest that ubiquinone is a target molecule in the effects of inhibition of respiration and death of yeast cells induced with near-UV (313 nm).

Candida↗
PubMedDate not supplied

[Preliminary and postradiation effect of long-wave ultraviolet rays on cells of different species of Candida irradiated with short-wave ultraviolet rays].

Certain characteristics of photoprotection induced by near-UV were studied in Candida guilliermondii. Candida tropicalis was also capable of photoprotection from the lethal effect of far-UV. The spectrum of action of photoprotection was recorded. The photoprotective effect was not found in Candida utilis. The postradiation effect of near-UV was studied. The lethal action of far-UV was intensified in C. guilliermondii and C. tropicalis incapable of photoreactivation in contrast to C. utilis capable of photoreactivation.

Candida↗
PubMedDate not supplied

Influence of near ultraviolet light on microorganisms.

Our results and the recent literature data on the biological action of near ultraviolet light (300-380 nm) are examined in the review. Factual material is presented on the principles governing the manifestation of the following effects of near ultraviolet light in microorganisms: inactivation, delayed growth, photoreactivation, photoprotection, photoinduced sporulation (in fungi), and carotene synthesis. The mature and possible mechanisms of the effects examined are discussed.

Bacteria↗
PubMedDate not supplied

[Dynamics of electronic excitation in the photosynthetic pigment apparatus].

The fluorescence lifetime and quantum yield as a function of single picosecond laser pulse intensity were experimentally studied in chloroplasts and subchloroplast particles. The intensity of laser pulse were changed from 3 x 10(12) to 10(17) photon/cm2. To explain experimental results it was considered that energy transport in the light harvesting antenna occurs by localised excitons. Parameters governing dynamic of electronic excitation within light harvesting antenna were determined. The diffusion coefficient was found to be 2 x 10(-2) cm2sec-1; diffusion length L greater than or equal to 900 A, energy transfer probability W approximately 10(12)sec-1. The rate of constant of energy transfer from light harvesting antenna to PS1 and PS2 reaction centers and effectiveness of the exciton capture by the PS2 reaction center were estimated.

Chloroplasts↗
PubMedDate not supplied

[Repair of damage caused by 313 nm light and photoprotection in Candida guilliermondii].

The study of the effect of near-UV light (300-380 nm) on the yeast Candida guilliermondii has shown that certain doses of 313 nm light cause inactivation which is reversible after the cells have been kept for some time in a non-nutrient medium. The findings suggest a different nature of the lesions resulting in killing the cells irradiated with light of 313 and 254 nm. The data obtained are interpreted in terms of a new, yet unknown, repair mechanism, other than the classical dark reparation, which is involved in the recovery of cells inactivated by light of 313 nm. Non-lethal doses at 313 nm induce photoprotection of the cells against UV lesions. The effect was compared with the photoprotection described in literature, and was found to be different.

Candida↗