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1.
Dermatology ; 235(6): 509-515, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31586997

RESUMEN

BACKGROUND: The phenomenon of photoadaptation to narrow-band ultraviolet B (NB-UVB) radiation has been previously described in vitiligo and has usually been clinically measured by the assessment of the minimal erythema dose (MED) after phototesting. OBJECTIVES: To assess the photoadaptive response in vitiligo and healthy skin after NB-UVB phototherapy not only clinically, but also by spectrophotometry. MATERIALS AND METHODS: Fourteen patients affected by generalized vitiligo underwent NB-UVB phototherapy twice weekly for 12 weeks. Before and after phototherapy, a phototesting procedure was administered on vitiligo patches and adjacent healthy skin with a solar simulated radiation (SSR). Visual assessment of the MED took place after 24 h. A spectrophotometer was used to assess the a* value and the melanin index (MI*), as signs of skin erythema and pigmentation. The photoadaptation factor (MED-PF) and the a* photoadaptation factor (a*-PF) were calculated. RESULTS: After NB-UVB phototherapy, both vitiligo and healthy skin showed an increase in MED and MI* values and a reduction of skin erythema compared to baseline (p < 0.05). MED-PF data showed a photoadaptation in 10 (71.4%) vitiligo lesions and in 12 (85.7%) healthy skin areas. The assessment of the a*-PF showed a negative mean percentage value in all affected and unaffected skin areas. CONCLUSIONS: A short cycle of NB-UVB phototherapy can induce photoadaptation in vitiligo by increasing the MED and reducing skin erythema after stimulation with SSR. This is most likely due to the physical filter function induced by ultraviolet radiation.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Pigmentación/efectos de la radiación , Piel/efectos de la radiación , Terapia Ultravioleta , Vitíligo/fisiopatología , Vitíligo/radioterapia , Adulto , Anciano , Eritema/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dosificación Radioterapéutica , Espectrofotometría , Terapia Ultravioleta/efectos adversos
2.
Mutat Res Rev Mutat Res ; 773: 188-203, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28927528

RESUMEN

The human population is continually exposed to numerous harmful environmental stressors, causing negative health effects and/or deregulation of biomarker levels. However, studies reporting no or even positive impacts of some stressors on humans are also sometimes published. The main aim of this review is to provide a comprehensive overview of the last decade of Czech biomonitoring research, concerning the effect of various levels of air pollution (benzo[a]pyrene) and radiation (uranium, X-ray examination and natural radon background), on the differently exposed population groups. Because some results obtained from cytogenetic studies were opposite than hypothesized, we have searched for a meaningful interpretation in genomic/epigenetic studies. A detailed analysis of our data supported by the studies of others and current epigenetic knowledge, leads to a hypothesis of the versatile mechanism of adaptation to environmental stressors via DNA methylation settings which may even originate in prenatal development, and help to reduce the resulting DNA damage levels. This hypothesis is fully in agreement with unexpected data from our studies (e.g. lower levels of DNA damage in subjects from highly polluted regions than in controls or in subjects exposed repeatedly to a pollutant than in those without previous exposure), and is also supported by differences in DNA methylation patterns in groups from regions with various levels of pollution. In light of the adaptation hypothesis, the following points may be suggested for future research: (i) the chronic and acute exposure of study subjects should be distinguished; (ii) the exposure history should be mapped including place of residence during the life and prenatal development; (iii) changes of epigenetic markers should be monitored over time. In summary, investigation of human adaptation to the environment, one of the most important processes of survival, is a new challenge for future research in the field of human biomonitoring that may change our view on the results of biomarker analyses and potential negative health impacts of the environment.


Asunto(s)
Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/efectos de la radiación , Citogenética , Monitoreo del Ambiente , Contaminación del Aire/efectos adversos , Benzo(a)pireno/toxicidad , Aberraciones Cromosómicas/efectos de los fármacos , Aberraciones Cromosómicas/efectos de la radiación , República Checa , Daño del ADN/efectos de los fármacos , Daño del ADN/efectos de la radiación , Metilación de ADN/efectos de los fármacos , Metilación de ADN/efectos de la radiación , Humanos , Uranio/toxicidad , Rayos X/efectos adversos
3.
Bioelectromagnetics ; 38(4): 245-254, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28072461

RESUMEN

In this study, the effect of radiofrequency (RF) exposure to 1950 MHz, Universal Mobile Telecommunication System signal, was investigated in Chinese hamster lung fibroblast cell line (V79). Genotoxic and cytotoxic effects of 20-h exposure at specific absorption rate (SAR) values from 0.15 W/kg to 1.25 W/kg were measured by means of cytokinesis-block micronucleus (MN) assay. Exposure was carried out blinded under strictly controlled conditions of dosimetry and temperature. The effect of RF exposure alone at four SAR values was tested, that is, 0.15, 0.3, 0.6, and 1.25 W/kg. A statistically significant increase in MN frequency was found in cultures exposed to 0.15 and 0.3 W/kg (P < 0.05) compared to sham-exposed ones, in the absence of cytotoxicity. SAR values of 0.6 and 1.25 W/kg did not exert any effect. Moreover, to evaluate the ability of RF to exert protective effects with respect to a chemical mutagen, cell cultures were also pre-exposed for 20 h at 0.3 or 1.25 W/kg, and then treated with 500 ng/ml of mitomycin-C (MMC). A significant reduction in the frequency of MN was detected in cultures pre-exposed to 1.25 W/kg compared to cultures treated with MMC alone (P < 0.05), indicating induction of adaptive response. Such a decrease was not induced by pre-exposure at 0.3 W/kg SAR. Taken together, our results indicated that V79 is a sensitive cell model to evidence either adverse or beneficial effects of RF exposure, depending on experimental conditions applied. Bioelectromagnetics. 38:245-254, 2017. © 2017 Wiley Periodicals, Inc.


Asunto(s)
Fibroblastos/efectos de la radiación , Pulmón/citología , Ondas de Radio/efectos adversos , Adaptación Fisiológica/efectos de la radiación , Animales , Línea Celular , Cricetinae , Cricetulus , Citocinesis/efectos de la radiación , Daño del ADN , Fibroblastos/citología , Fibroblastos/metabolismo , Pruebas de Micronúcleos
4.
Mol Plant Pathol ; 15(9): 940-7, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24754446

RESUMEN

Burkholderia glumae is the major causal agent of bacterial panicle blight of rice, which is a growing disease problem for rice growers worldwide. In our previous study, some B. glumae strains showed pigmentation phenotypes producing at least two (yellow-green and purple) pigment compounds in casein-peptone-glucose agar medium. The B. glumae strains LSUPB114 and LSUPB116 are pigment-deficient mutant derivatives of the virulent and pigment-proficient strain 411gr-6, having mini-Tn5gus insertions in aroA encoding 3-phosphoshikimate 1-carboxyvinyltransferase and aroB encoding 3-dehydroquinate synthase, respectively. Both enzymes are known to be involved in the shikimate pathway, which leads to the synthesis of aromatic amino acids. Here, we demonstrate that aroA and aroB are required for normal virulence in rice and onion, growth in M9 minimal medium and tolerance to UV light, but are dispensable for the production of the phytotoxin toxoflavin. These results suggest that the shikimate pathway is involved in bacterial pathogenesis by B. glumae without a significant role in the production of toxoflavin, a major virulence factor of this pathogen.


Asunto(s)
Adaptación Fisiológica/genética , Burkholderia/genética , Burkholderia/patogenicidad , Genes Bacterianos , Redes y Vías Metabólicas/genética , Ácido Shikímico/metabolismo , Rayos Ultravioleta , Adaptación Fisiológica/efectos de la radiación , Burkholderia/crecimiento & desarrollo , Burkholderia/efectos de la radiación , Glicina/análogos & derivados , Glicina/toxicidad , Redes y Vías Metabólicas/efectos de la radiación , Viabilidad Microbiana/efectos de los fármacos , Viabilidad Microbiana/efectos de la radiación , Mutación/genética , Cebollas/microbiología , Oryza/microbiología , Pigmentos Biológicos/metabolismo , Enfermedades de las Plantas/microbiología , Pirimidinonas/metabolismo , Triazinas/metabolismo , Virulencia/efectos de la radiación , Glifosato
5.
Planta ; 239(5): 1101-11, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24563249

RESUMEN

Screening of 40,000 Arabidopsis FOX (Full-length cDNA Over-eXpressor gene hunting system) lines expressing rice full-length cDNAs brings us to identify four cadmium (Cd)-tolerant lines, one of which carried OsREX1-S as a transgene. OsREX1-S shows the highest levels of identity to Chlamydomonas reinhardtii REX1-S (referred to as CrREX1-S, in which REX denotes Required for Excision) and to yeast and human TFB5s (RNA polymerase II transcription factor B5), both of which are components of the general transcription and DNA repair factor, TFIIH. Transient expression of OsREX1-S consistently localized the protein to the nucleus of onion cells. The newly generated transgenic Arabidopsis plants expressing OsREX1-S reproducibly displayed enhanced Cd tolerance, confirming that the Cd-tolerance of the initial identified line was conferred solely by OsREX1-S expression. Furthermore, transgenic Arabidopsis plants expressing OsREX1-S exhibited ultraviolet-B (UVB) tolerance by reducing the amounts of cyclobutane pyrimidine dimers produced by UVB radiation. Moreover, those transgenic OsREX1-S Arabidopsis plants became resistant to bleomycin (an inducer of DNA strand break) and mitomycin C (DNA intercalating activity), compared to wild type. Our results indicate that OsREX1-S renders host plants tolerant to Cd, UVB radiation, bleomycin and mitomycin C through the enhanced DNA excision repair.


Asunto(s)
Cadmio/toxicidad , Daño del ADN , Reparación del ADN/efectos de la radiación , Oryza/metabolismo , Células Vegetales/efectos de la radiación , Proteínas de Plantas/metabolismo , Factor de Transcripción TFIIH/metabolismo , Rayos Ultravioleta , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/efectos de la radiación , Secuencia de Aminoácidos , Arabidopsis/efectos de los fármacos , Arabidopsis/genética , Arabidopsis/fisiología , Arabidopsis/efectos de la radiación , Bleomicina , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Núcleo Celular/efectos de la radiación , Reparación del ADN/efectos de los fármacos , ADN Complementario/genética , Humanos , Mitomicina , Datos de Secuencia Molecular , Cebollas/citología , Oryza/efectos de los fármacos , Oryza/efectos de la radiación , Fenotipo , Células Vegetales/efectos de los fármacos , Proteínas de Plantas/química , Plantas Modificadas Genéticamente , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/efectos de la radiación , Dímeros de Pirimidina/metabolismo , Saccharomyces cerevisiae/metabolismo , Plantones/efectos de los fármacos , Plantones/efectos de la radiación , Homología de Secuencia de Aminoácido , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/metabolismo , Fracciones Subcelulares/efectos de la radiación
6.
Br J Dermatol ; 170(2): 392-7, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24125495

RESUMEN

BACKGROUND: Photoadaptation describes the skin's ability to withstand an increased dose of ultraviolet (UV) radiation with repeated exposure, and this is the reason for exposure doses being increased during a course of phototherapy. However, directly measured data on photoadaptation are available only for broadband (BB) and not narrowband (NB)-UVB. OBJECTIVES: To measure photoadaptation to narrowband UVB. METHODS: We measured the degree of photoadaptation in patients with psoriasis during a standard course of NB-UVB phototherapy. The minimal erythemal dose (MED) was measured before and towards the end of a course of phototherapy. An adaptation factor (AF) was calculated for each patient using the ratio of final MED to initial MED. Sigmoid dose-response curves were also constructed. RESULTS: MED results were available for 50 patients (mean age 44 years, 28 female). The mean AF was 2·7 (95% confidence interval 2·4-3·0). There was no significant correlation between AF and skin type or initial MED. Dose-response curves were right shifted and parallel after phototherapy, and there was no significant difference in the maximum slope (P = 0·73). CONCLUSIONS: The photoadaptation caused by NB-UVB is considerably less than that reported for BB-UVB. The variation in photoadaptation between patients was not explained by skin type or baseline MED. Physical factors (such as tanning and epidermal thickening) are probably sufficient to account for photoadaptation, rather than downregulation of the inflammatory response. These data should help in the design of phototherapy protocols for NB-UVB to achieve optimal clearance of psoriasis.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Piel/efectos de la radiación , Rayos Ultravioleta , Adulto , Relación Dosis-Respuesta en la Radiación , Femenino , Humanos , Masculino , Psoriasis/radioterapia , Radiometría , Terapia Ultravioleta/métodos
7.
PLoS One ; 8(12): e83960, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24386315

RESUMEN

Aerobic anoxygenic phototrophs (AAPs) as being photoheterotrophs require organic substrates for growth and use light as a supplementary energy source under oxic conditions. We hypothesized that AAPs benefit from light particularly under carbon and electron donor limitation. The effect of light was determined in long-term starvation experiments with Dinoroseobacter shibae DFL 12(T) in both complex marine broth and defined minimal medium with succinate as the sole carbon source. The cells were starved over six months under three conditions: continuous darkness (DD), continuous light (LL), and light/dark cycle (LD, 12 h/12 h, 12 µmol photons m(-2) s(-1)). LD starvation at low light intensity resulted in 10-fold higher total cell and viable counts, and higher bacteriochlorophyll a and polyhydroxyalkanoate contents. This coincided with better physiological fitness as determined by respiration rates, proton translocation and ATP concentrations. In contrast, LD starvation at high light intensity (>22 µmol photons m(-2) s(-1), LD conditions) resulted in decreasing cell survival rates but increasing carotenoid concentrations, indicating a photo-protective response. Cells grown in complex medium survived longer starvation (more than 20 weeks) than those grown in minimal medium. Our experiments show that D. shibae benefits from the light and dark cycle, particularly during starvation.


Asunto(s)
Medios de Cultivo/química , Luz , Rhodobacteraceae/citología , Rhodobacteraceae/efectos de la radiación , Adaptación Fisiológica/efectos de la radiación , Proliferación Celular/efectos de la radiación , Relación Dosis-Respuesta en la Radiación , Rhodobacteraceae/fisiología
8.
Birth Defects Res B Dev Reprod Toxicol ; 95(6): 379-85, 2012 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23109298

RESUMEN

BACKGROUND: Adaptive response (AR) of low linear energy transfer (LET) irradiations for protection against teratogenesis induced by high LET irradiations is not well documented. In this study, induction of AR by X-rays against teratogenesis induced by accelerated heavy ions was examined in fetal mice. METHODS: Irradiations of pregnant C57BL/6J mice were performed by delivering a priming low dose from X-rays at 0.05 or 0.30 Gy on gestation day 11 followed one day later by a challenge high dose from either X-rays or accelerated heavy ions. Monoenergetic beams of carbon, neon, silicon, and iron with the LET values of about 15, 30, 55, and 200 keV/µm, respectively, were examined. Significant suppression of teratogenic effects (fetal death, malformation of live fetuses, or low body weight) was used as the endpoint for judgment of a successful AR induction. RESULTS: Existence of AR induced by low-LET X-rays against teratogenic effect induced by high-LET accelerated heavy ions was demonstrated. The priming low dose of X-rays significantly reduced the occurrence of prenatal fetal death, malformation, and/or low body weight induced by the challenge high dose from either X-rays or accelerated heavy ions of carbon, neon or silicon but not iron particles. CONCLUSIONS: Successful AR induction appears to be a radiation quality event, depending on the LET value and/or the particle species of the challenge irradiations. These findings would provide a new insight into the study on radiation-induced AR in utero.


Asunto(s)
Anomalías Inducidas por Radiación/etiología , Adaptación Fisiológica/efectos de la radiación , Iones Pesados/efectos adversos , Transferencia Lineal de Energía , Tolerancia a Radiación/efectos de la radiación , Animales , Carbono/efectos adversos , Relación Dosis-Respuesta en la Radiación , Femenino , Muerte Fetal , Desarrollo Fetal/efectos de la radiación , Peso Fetal/efectos de la radiación , Feto/efectos de la radiación , Hierro/efectos adversos , Masculino , Ratones , Ratones Endogámicos C57BL , Neón/efectos adversos , Embarazo , Tolerancia a Radiación/fisiología , Radiación Ionizante , Silicio/efectos adversos , Rayos X
9.
Ecotoxicology ; 21(4): 1225-39, 2012 May.
Artículo en Inglés | MEDLINE | ID: mdl-22396021

RESUMEN

Natural populations are chronically exposed to various pollutants over many generations. It is thus crucial to understand and quantify adaptive dynamics of stressed populations in order to increase the relevance of ecotoxicological risk assessment. However, long-term consequences to population exposure are not much studied yet. The present study investigated evolutionary responses of Chironomus riparius populations exposed to uranium (heavy metal pollutant) and to assess the underlying mechanisms. To fulfil our objective, we produced data with organisms exposed to four relevant concentrations of uranium through eight successive generations. We built an individual-based (IBM) model of C. riparius population dynamics to analyse these data and to test several assumptions about the mechanisms involved in the phenotypic changes. The IBM was based on a dynamic energy budget (DEB) model for C. riparius by Pery et al. (2002). DEB models account mathematically for the acquisition and use of energy to describe and predict growth, maintenance, development and reproduction of living organisms. The IBM accounted for the influence of the test conditions on the observations over eight generations and highlighted some trait evolution such as time to emergence and adult size in control conditions. The model was then used to analyse the exposed population data. Our results showed that exposure to uranium led to a phenotypic selection via a differential survival characterised by longer time to emergence and smaller larval maximal size. As a general conclusion, IBMs based on DEB-based modelling developed to analyse multi-generation experiments are very promising for understanding and quantifying long term selection and tolerance mechanisms in a population under toxic stress.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Chironomidae/efectos de la radiación , Sedimentos Geológicos/química , Uranio/toxicidad , Contaminantes Químicos del Agua/toxicidad , Animales , Chironomidae/crecimiento & desarrollo , Monitoreo del Ambiente , Sedimentos Geológicos/análisis , Larva/efectos de la radiación , Modelos Teóricos , Dinámica Poblacional , Reproducción/efectos de la radiación , Medición de Riesgo , Uranio/análisis , Contaminantes Químicos del Agua/análisis
10.
PLoS One ; 6(9): e24346, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21912689

RESUMEN

Despite proposed ecological importance of mucilage in seed dispersal, germination and seedling establishment, little is known about the role of mucilage in seed pre-germination processes. Here we investigated the role of mucilage in assisting achene cells to repair DNA damage during dew deposition in the desert. Artemisia sphaerocephala achenes were first treated γ-irradiation to induce DNA damage, and then they were repaired in situ in the desert dew. Dew deposition duration can be as long as 421 min in early mornings. Intact achenes absorbed more water than demucilaged achenes during dew deposition and also carried water for longer time following sunrise. After 4-d dew treatment, DNA damage of irradiated intact and demucilaged achenes was reduced to 24.38% and 46.84%, respectively. The irradiated intact achenes exhibited much higher DNA repair ratio than irradiated demucilaged achenes. Irradiated intact achenes showed an improved germination and decreased nonviable achenes after dew treatment, and significant differences in viability between the two types of achenes were detected after 1020 min of dew treatment. Achene mucilage presumably plays an ecologically important role in the life cycle of A. sphaerocephala by aiding DNA repair of achene cells in genomic-stressful habitats.


Asunto(s)
Adaptación Fisiológica , Adhesivos/metabolismo , Artemisia/fisiología , ADN de Plantas/genética , Clima Desértico , Frutas/metabolismo , Agua/metabolismo , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/genética , Adaptación Fisiológica/efectos de la radiación , Artemisia/efectos de los fármacos , Artemisia/metabolismo , Artemisia/efectos de la radiación , Daño del ADN/genética , Reparación del ADN/efectos de los fármacos , Reparación del ADN/genética , Reparación del ADN/efectos de la radiación , Frutas/efectos de los fármacos , Frutas/fisiología , Frutas/efectos de la radiación , Genoma de Planta/genética , Germinación/efectos de los fármacos , Germinación/genética , Germinación/efectos de la radiación , Agua/farmacología
11.
Adv Gerontol ; 23(2): 301-3, 2010.
Artículo en Ruso | MEDLINE | ID: mdl-21033387
12.
Br J Dermatol ; 160(3): 534-9, 2009 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-19067714

RESUMEN

BACKGROUND: Photoadaptation to ultraviolet (UV) B phototherapy is due to both pigmentary and nonpigmentary influences. OBJECTIVES: To measure photoadaptation in vitiliginous skin and to compare it with normal pigmented skin. METHODS: Seventeen patients with Fitzpatrick skin phototypes III-VI with vitiligo received six to nine UVB treatments, two to three times weekly. Minimal erythema dose (MED) testing was done at baseline and after all treatments; the percentage change in MED was analysed as a measure of photoadaptation. The percentage decrease in cyclobutane pyrimidine dimers (CPDs) over 24 h after a single exposure of 1 MED was analysed on vitiliginous and normal skin. RESULTS: The mean +/- SD percentage change in MED from before to after treatments was: treated vitiliginous skin 28.5 +/- 39.9% (P = 0.015), treated normal skin 35.9 +/- 49.9% (P = 0.015), untreated vitiliginous skin 11.9 +/- 22.6% (P =0.070), untreated normal skin 25.1 +/- 41.3% (P = 0.041). Of these patients, two-thirds had a positive percentage change in MED (photoadaptation). The mean amount of CPDs induced per megabase of DNA immediately after exposure was significantly higher in vitiliginous skin. The mean +/- SD percentage decrease in CPDs (rate of repair) in 24 h was 35.7 +/- 26.8% in vitiliginous skin (P = 0.027) and 46.2 +/- 19.5% in normally pigmented skin (P = 0.001); no difference was noted in the repair in vitiliginous skin compared with normal skin (P = 0.4). CONCLUSIONS: Photoadaptation in vitiliginous and normal skin was observed in two-thirds of patients. Vitiliginous skin had significantly more CPDs following UVB exposure; the rate of repair of UVB-induced DNA damage was equivalent to that in normal skin.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Terapia Ultravioleta/métodos , Vitíligo/radioterapia , Adaptación Fisiológica/genética , Adulto , Anciano , Daño del ADN , Reparación del ADN , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tolerancia a Radiación/genética , Dosificación Radioterapéutica , Piel/efectos de la radiación , Pigmentación de la Piel , Vitíligo/genética , Vitíligo/fisiopatología
13.
Ying Yong Sheng Tai Xue Bao ; 19(5): 961-8, 2008 May.
Artículo en Chino | MEDLINE | ID: mdl-18655578

RESUMEN

A factorial combination pot experiment was designed to study the growth response and foraging behavior of three South China forestation species Pinus massoniana, Schima superba and Liriodendron chinense under heterogenous nutrient envionment and different light conditions. The results demonstrated that under full light, the plant height and biomass of P. massoniana and S. superba were enhanced in heterogenous nutrient environment, with the root biomass increased by 99.5% and 66.7%, respectively, compared with that in homogenous environment; while L. chinense exhibited singnificant growth benefits in homogenous environment. The root scale, foraging precision, and nutrient uptake of S. superba reduced markedly under shading, which in turn decreased the growth benefits in heterogenous nutrient environment. The influence of shading was weaker on P. massoniana than on S. superba, still with some growth benefits for P. massoniana due to its root proliferation and enhanced nutrient uptake in nutrient rich patch. There was a slight influence of shading on the foraging precision and sensitivity of L. chinense root, with no growth response pattern change to heterogenous nutient environment occurred. It was concluded that three tree species not only differed in the inheritance of root foraging mechanism and behavior, but also varied in the response pattern to light condition. Therefore, different measures should be adopted in forestation with the three tree species to enhance the forest productivity.


Asunto(s)
Luz , Raíces de Plantas/fisiología , Suelo/análisis , Árboles/fisiología , Adaptación Fisiológica/efectos de la radiación , Ecosistema , Liriodendron/crecimiento & desarrollo , Liriodendron/fisiología , Nitrógeno/metabolismo , Fósforo/metabolismo , Pinus/crecimiento & desarrollo , Pinus/fisiología , Raíces de Plantas/crecimiento & desarrollo , Especificidad de la Especie , Árboles/crecimiento & desarrollo
14.
Ying Yong Sheng Tai Xue Bao ; 19(3): 505-11, 2008 Mar.
Artículo en Chino | MEDLINE | ID: mdl-18533517

RESUMEN

The study on the photosynthetic characteristics and dry matter accumulation of twelve hybrid rice varieties in the eco-environments with low- and high light intensity showed that the adaptation abiility of the varieties to eco-environment was mainly (depended on the varieties themselves, and there existed greater (differenees among them. The differences in net photosynthetic rate (Pn) and chlorophyll content (Chl) were more significant among the varieties than between the eco-environments. The grain yield had significant positive correlations with Pn and total dry matter mass (TDM), the determination coefficient R2 being 0.584 and 0.590, respectively, but no significant correlations with the export percentage of the matter in stem-sheath (EPMSS) and the transformation percentage of the matter in stem-sheath (TPMSS). In the eco-environment with high light intensity, the leaf thickness and dry matter accumulation increased, while the EPMSS and TPMSS decreased. Under enough sunlight condition, the high proportion of matter in grain yield was mainly come from the photosynthesis at late growth stages; while under insufficient sunlight condition, it was mainly originated from the early growth stages photosynthesis.


Asunto(s)
Biomasa , Oryza/efectos de la radiación , Fotosíntesis/efectos de la radiación , Luz Solar , Adaptación Fisiológica/efectos de la radiación , Clorofila/análisis , Ecosistema , Grano Comestible/química , Grano Comestible/metabolismo , Hibridación Genética , Oryza/genética , Oryza/crecimiento & desarrollo , Fósforo/análisis
15.
Ann Bot ; 101(2): 277-83, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17495979

RESUMEN

BACKGROUND AND AIMS: Repair of damage to DNA of seed embryos sustained during long periods of quiescence under dry desert conditions is important for subsequent germination. The possibility that repair of embryo DNA can be facilitated by small amounts of water derived from dew temporarily captured at night by pectinaceous surface pellicles was tested. These pellicles are secreted during early seed development and form mucilage when hydrated. METHODS: Seeds of Artemisia sphaerocephala and Artemisia ordosica were collected from a sandy desert. Their embryos were damaged by gamma radiation to induce a standard level of DNA damage. The treated seeds were then exposed to nocturnal dew deposition on the surface of soil in the Negev desert highlands. The pellicles were removed from some seeds and left intact on others to test the ability of mucilage to support repair of the damaged DNA when night-time humidity and temperature favoured dew formation. Repair was assessed from fragmentation patterns of extracted DNA on agarose gels. KEY RESULTS: For A. sphaerocephala, which has thick seed pellicles, DNA repair occurred in seeds with intact pellicles after 50 min of cumulative night dew formation, but not in seeds from which the pellicles had been removed. For A. ordosica, which has thin seed pellicles, DNA repair took at least 510 min of cumulative night dewing to achieve partial recovery of DNA integrity. The mucilage has the ability to rehydrate after daytime dehydration. CONCLUSIONS: The ability of seeds to develop a mucilaginous layer when wetted by night-time dew, and to repair their DNA under these conditions, appear to be mechanisms that help maintain seed viability under harsh desert conditions.


Asunto(s)
Adaptación Fisiológica , Adhesivos/metabolismo , Reparación del ADN , ADN de Plantas/metabolismo , Pectinas/metabolismo , Semillas/metabolismo , Agua/metabolismo , Adaptación Fisiológica/efectos de la radiación , Artemisia/efectos de la radiación , Artemisia/ultraestructura , Ritmo Circadiano/efectos de la radiación , Reparación del ADN/efectos de la radiación , Clima Desértico , Rayos gamma , Humedad , Semillas/genética , Semillas/efectos de la radiación , Semillas/ultraestructura , Factores de Tiempo
16.
Ann Bot ; 101(2): 267-76, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17981881

RESUMEN

BACKGROUND AND AIMS: The plants that have remained in the contaminated areas around Chernobyl since 1986 encapsulate the effects of radiation. Such plants are chronically exposed to radionuclides that they have accumulated internally as well as to alpha-, beta- and gamma-emitting radionuclides from external sources and from the soil. This radiation leads to genetic damage that can be countered by DNA repair systems. The objective of this study is to follow DNA repair and adaptation in haploid cells (birch pollen) and diploid cells (seed embryos of the evening primrose) from plants that have been growing in situ in different radionuclide fall-out sites in monitored regions surrounding the Chernobyl explosion of 1986. METHODS: Radionuclide levels in soil were detected using gamma-spectroscopy and radiochemistry. DNA repair assays included measurement of unscheduled DNA synthesis, electrophoretic determination of single-strand DNA breaks and image analysis of rDNA repeats after repair intervals. Nucleosome levels were established using an ELISA kit. KEY RESULTS: Birch pollen collected in 1987 failed to perform unscheduled DNA synthesis, but pollen at gamma/beta-emitter sites has now recovered this ability. At a site with high levels of combined alpha- and gamma/beta-emitters, pollen still exhibits hidden damage, as shown by reduced unscheduled DNA synthesis and failure to repair lesions in rDNA repeats properly. Evening primrose seed embryos generated on plants at the same gamma/beta-emitter sites now show an improved DNA repair capacity and ability to germinate under abiotic stresses (salinity and accelerated ageing). Again those from combined alpha- and gamma/beta-contaminated site do not show this improvement. CONCLUSIONS: Chronic irradiation at gamma/beta-emitter sites has provided opportunities for plant cells (both pollen and embryo cells) to adapt to ionizing irradiation and other environmental stresses. This may be explained by facilitation of DNA repair function.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Betula/efectos de la radiación , Accidente Nuclear de Chernóbil , Reparación del ADN/efectos de la radiación , Oenothera biennis/efectos de la radiación , Polen/efectos de la radiación , Radioisótopos/farmacología , Semillas/efectos de la radiación , Adaptación Fisiológica/efectos de los fármacos , Betula/efectos de los fármacos , Betula/genética , Betula/fisiología , Roturas del ADN de Cadena Simple/efectos de los fármacos , Roturas del ADN de Cadena Simple/efectos de la radiación , Reparación del ADN/efectos de los fármacos , Enzimas de Restricción del ADN/metabolismo , ADN de Plantas/biosíntesis , Relación Dosis-Respuesta en la Radiación , Germinación/efectos de los fármacos , Germinación/efectos de la radiación , Nucleosomas/efectos de los fármacos , Nucleosomas/efectos de la radiación , Oenothera biennis/genética , Oenothera biennis/fisiología , Presión Osmótica/efectos de los fármacos , Presión Osmótica/efectos de la radiación , Polen/efectos de los fármacos , Polen/genética , Plantones/efectos de los fármacos , Plantones/efectos de la radiación , Semillas/efectos de los fármacos , Semillas/genética , Cloruro de Sodio/farmacología , Factores de Tiempo
17.
Photodermatol Photoimmunol Photomed ; 23(6): 258-60, 2007 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17986064

RESUMEN

BACKGROUND: Increasing doses of ultraviolet (UV) radiation are tolerated in patients with vitiligo, due to photoadaptation. In this pilot study, five patients with Fitzpatrick skin phototypes IV-VI with vitiligo received six treatments of targeted UVB phototherapy over a 3-week period. METHODS: To investigate photoadaptation, minimal erythema dose (MED) testing was conducted on treated and untreated vitiliginous and normal skin at baseline and after three and six treatments. One patient had unattainable MED values, and was hence excluded. RESULTS: Percent change in MED from before to after all treatments in vitiliginous skin ranged from 0% to 128%, with a mean of 48.8%. CONCLUSION: The pilot phase of this study suggests possible photoadaptation of vitiliginous skin of some patients to targeted UVB phototherapy.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Enfermedades de la Piel/patología , Enfermedades de la Piel/radioterapia , Terapia Ultravioleta , Adulto , Anciano , Humanos , Persona de Mediana Edad , Proyectos Piloto , Piel/efectos de la radiación
18.
Ukr Biokhim Zh (1999) ; 79(3): 70-8, 2007.
Artículo en Ucraniano | MEDLINE | ID: mdl-17988017

RESUMEN

Two fast migrating, major, multiple molecular forms (MMF) of glucose-6-phosphate dehydrogenase [EC:1.1.1.49]: G-6-PDH-1 and G-6-PDH-2, and two minor forms: G-6-PDH-3 and G-6-PDH-4 were revealed in the electrophoregrams of both erythrocytes haemolisates as well in the homogenates of bone marrow cellular lines of rats at control conditions. Daily 1 cGy irradiation of rats up to a cumulative dose of 20 cGy led to a drop of G-6-PDH total activity and it caused a redistribution of the MMF of the enzyme in bone marrow cellular populations. However, G-6-PDH activity in erythrocytes exceeded the control means in all the experimental terms. The calculation of the local redistribution coefficient (l(G-6-FDH-i)) showed that these changes are mainly determined by the increase of the activity of the isoform G-6-PDH-3. Vitamin D3 administration to rats generated a correction of G-6-PDH activity in all studied cellular populations. Meanwhile, the MMF profiles were characterized by multidirectional rearrangements in the bone marrow erythroid and granulocyte-monocyte cells and in erythrocytes. The specificity of changes in the distribution of the MMF of G-6-PDH in the three studied cellular populations depends on the particularities of their energetic metabolism at irradiation conditions and on the modifying action of the natural adaptogen 1,25-dihydroxicholecalciferol.


Asunto(s)
Adaptación Fisiológica , Colecalciferol/farmacología , Eritrocitos , Células Precursoras Eritroides , Glucosafosfato Deshidrogenasa/metabolismo , Irradiación Corporal Total , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/efectos de la radiación , Animales , Colecalciferol/administración & dosificación , Suplementos Dietéticos , Eritrocitos/efectos de los fármacos , Eritrocitos/enzimología , Eritrocitos/efectos de la radiación , Células Precursoras Eritroides/efectos de los fármacos , Células Precursoras Eritroides/enzimología , Células Precursoras Eritroides/efectos de la radiación , Dosis de Radiación , Ratas
19.
Fiziol Zh (1994) ; 53(2): 56-64, 2007.
Artículo en Ucraniano | MEDLINE | ID: mdl-17595913

RESUMEN

According to the positions of systemic analysis of autoregulations and systemic reconstruction processes in children under the influence of PILER-light (Polarized polychromatic incoherent low-energy radiation) depending on the type of general non-specific adaptation reactions of the organism, the clinical blood test has been investigated using the correlation structures method. It has been established that phototherapy with polarized light causes stereotype effect of increased integration between the blood parameters, harmonizing of white and red blood parameters, elimination of the stress, decreased entropy elements. At the same time the specific adaptation reaction of the child's organism to the loadings of various origin, in particular, to the electromagnetic irradiation of optic diapason waves indicates the diverse character of the changed regulation system functions depending on the adaptation reaction type and grounds the differentiated approach to the polarized light therapy.


Asunto(s)
Adaptación Fisiológica/efectos de la radiación , Luz , Fototerapia/métodos , Infecciones del Sistema Respiratorio , Niño , Preescolar , Humanos , Recuento de Leucocitos , Leucocitos/citología , Leucocitos/efectos de la radiación , Luz/efectos adversos , Linfocitos/citología , Linfocitos/efectos de la radiación , Fototerapia/instrumentación , Infecciones del Sistema Respiratorio/sangre , Infecciones del Sistema Respiratorio/etiología , Infecciones del Sistema Respiratorio/fisiopatología , Infecciones del Sistema Respiratorio/prevención & control , Resultado del Tratamiento
20.
Radiats Biol Radioecol ; 46(1): 71-6, 2006.
Artículo en Ruso | MEDLINE | ID: mdl-16579547

RESUMEN

On the example of the physiological and the cytology-biochemical characteristics variability of an Atriplex patula L. and Artemisia vulgaris L. sprouts which parental plants were generated in various environmental conditions (South Yakutia, the Central Yakutia, Middle Ural), was shown, that radiostability depends not only on set protective antioxidant, on the DNA-reparation systems and on the vulnerability degree of a functioning genome, but also on the phenotypic diversifications of a population which in turn, in the certain degree, are consequence of previous selection of a population to all set of ecological stresses-factors of the environment.


Asunto(s)
Artemisia , Atriplex , Tolerancia a Radiación/fisiología , Plantones , Adaptación Fisiológica/efectos de la radiación , Antioxidantes/metabolismo , Artemisia/crecimiento & desarrollo , Artemisia/metabolismo , Artemisia/efectos de la radiación , Atriplex/crecimiento & desarrollo , Atriplex/metabolismo , Atriplex/efectos de la radiación , Clima , Fenómenos Fisiológicos de las Plantas/efectos de la radiación , Monitoreo de Radiación , Federación de Rusia , Estaciones del Año , Plantones/crecimiento & desarrollo , Plantones/metabolismo , Plantones/efectos de la radiación
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