Abstract:
BACKGROUND:Global warming directly influencing ozone layer depletion, which eventually is increasing ultraviolet radiation penetration having far-reaching impacts on living biota. This particularly influences the primary producer microalgae which are the basic unit of food webs in the aquatic habitats. Therefore, it is necessary to concentrate the research at this micro-level to understand the harmful impact of increased UV-B radiation ever before. Consequently, the present attempt aimed to focus on the influence of UV-B on growth criteria, photosynthetic pigments, some metabolites, and ultrastructure of the freshwater cyanobacteria, Planktothrix cryptovaginata (Microcoleaceae), Nostoc carneum (Nostocaceae), Microcystis aeruginosa (Microcystaceae), the Chlorophyte Scenedesmus acutus (Scenedesmaceae), and the marine Cyanobacterium Microcystis (Microcystaceae). METHODS:The cultures of investigated algae were subjected directly to different duration periods (1, 3, 5, and 7 h) of artificial UV-B in addition to unirradiated control culture and allowed to grow for 10 days, after which the algal samples were analyzed for growth, photosynthetic activities, primary metabolities and cellular ultrastructure. RESULTS:A remarkable inhibitory influence of UV-B was observed on growth criteria (measured as optical density and dry weight) and photosynthetic pigments of P. cryptovaginata, N. carneum, M. aeruginosa, S. acutus, and marine Microcystis. Where increasing the exposure time of UV-B was accompanied by increased inhibition. The variation in carbohydrate and protein contents under UV stress was based on the exposure periods and the algal species. The variation in algal ultrastructure by UV-B stress was noticed by an Electron Microscope. Cells damage and lysis, cell wall and cell membrane ruptured and release of intracellular substances, loss of cell inclusion, plasmolysis and necrosis, or apoptosis of the algal cells were observed by exposure to 7 h of UV-B. CONCLUSION:Exposure to UV-B has a marked harmful impact on the growth, pigments, and metabolic activity, as well as the cellular ultrastructure of some cyanobacteria and chlorophytes.
journal_name
Int J Radiat Bioljournal_title
International journal of radiation biologyauthors
El-Sheekh MM,Alwaleed EA,Ibrahim A,Saber Hdoi
10.1080/09553002.2021.1851060subject
Has Abstractpub_date
2020-12-03 00:00:00pages
1-15eissn
0955-3002issn
1362-3095pub_type
杂志文章abstract:PURPOSE:Ionizing radiation has been recognized to increase the risk of cardiovascular diseases (CVD). However, there is no consensus concerning the dose-risk relationship for low radiation doses and a mechanistic understanding of low dose effects is needed. MATERIAL AND METHODS:Previously, human umbilical vein endothe...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2014.905724
更新日期:2014-07-01 00:00:00
abstract::Cultures of JU-56 cells were irradiated in either G1 or G2 and examined either in their first post-irradiation metaphase (in diploids) or in their second post-irradiation metaphase (in colcemid-induced tetraploids). The timing of fixation, together with tritiated thymidine pulse labelling, allowed selection for scorin...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009314552131
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abstract::Intact Chinese hamster ovary cells were exposed to the restriction endonucleases (REs) AluI or BamHI. In metaphase spreads from these cells, 300 breakpoints per RE were localized in G-banded chromosome type aberrations (dicentrics, translocations, rings, terminal and interstitial deletions). The majority of breakpoint...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009514551401
更新日期:1995-10-01 00:00:00
abstract::The response to radiation of seven osteosarcoma cell lines was analysed by in vitro colony-forming assay and compared with that of eight human fibroblast strains. The values of D0, the surviving fraction after 2 Gy (S2Gy), and the mean inactivation dose (D) of osteosarcoma cells in log-phase culture were significantly...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009214552351
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abstract::The effects of UV radiation on humans and animals are receiving increasing attention and much interest has recently been focused on the environmental effects of UV A and UV B. This study compares the in vitro effects of UV A and UV B on the clonogenic survival of two human skin keratinocyte cell lines, HaCaT which are...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530097143590
更新日期:1997-07-01 00:00:00
abstract::The kinetic scheme of the reaction of desferrioxamine (DFO) with O2-. was studied using pulse and gamma-radiolysis. The rate constant k(O2-. + DFO) is equal to 1.3 +/- 0.1 x 10(6) dm3 mol-1s-1 at pH 7.4. Studying the competition between DFO and ferricytochrome-c for O2-. generated by gamma-radiolysis, we observed that...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553008914552381
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journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553008914551331
更新日期:1989-08-01 00:00:00
abstract::During previous studies on the relationship between thermosensitivity and intracellular pH (pHi) regulation in mammalian cells, we observed that the thermoresistant TR-4 cells appeared to be resistant to manipulations of the Na+/H+ antiport, one of the two primary membrane regulators of pHi. We hypothesized that this ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530096144969
更新日期:1996-10-01 00:00:00
abstract:PURPOSE:Since the exact development of posterior subcapsular cataracts (PSCs) is poorly understood, we review various risk factors and propose a two-stage etiology for PSCs. METHODS:The biological mechanisms associated with age-related cataracts (primarily nuclear cataracts, cortical cataracts and PSCs) were reviewed ...
journal_title:International journal of radiation biology
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更新日期:2020-11-01 00:00:00
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journal_title:International journal of radiation biology
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abstract::The in vitro cell survival of a human cervix carcinoma cell line (HX156c) has been assessed using 60Co gamma-rays administered at either high (150 cGy/min) or low (3.2 cGy/min) dose rate. Recovery during low dose-rate irradiation was observed; the dose reduction factor at 10(-2) cell kill for 150 versus 3.2 cGy/min wa...
journal_title:International journal of radiation biology
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doi:10.1080/09553008814551671
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abstract::A procedure based on a logistic regression model was used to estimate the dose-modifying effect of chemotherapy on the response of normal tissues to radiation. The magnitude of this modifying effect is usually expressed as a dose-effect factor (DEF). Values > 1.0 indicate an enhancing effect of chemotherapy while valu...
journal_title:International journal of radiation biology
pub_type: 临床试验,杂志文章
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更新日期:1994-06-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章,随机对照试验
doi:10.3109/09553002.2012.661916
更新日期:2012-05-01 00:00:00
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journal_title:International journal of radiation biology
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doi:10.3109/09553002.2014.901579
更新日期:2014-06-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000400017689
更新日期:2004-11-01 00:00:00
abstract:UNLABELLED:Abstract Purpose: Sensitizing cancer cells to irradiation is a major challenge in clinical oncology. We aimed to define the signal transduction pathways involved in poly(ADP-ribose) polymerase (PARP) inhibitor-induced radiosensitization in various mammalian cancer lines. MATERIALS AND METHODS:Clonogenic sur...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.3109/09553002.2014.934927
更新日期:2014-12-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009514551681
更新日期:1995-12-01 00:00:00
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pub_type: 杂志文章
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更新日期:2011-07-01 00:00:00
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更新日期:1997-03-01 00:00:00
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更新日期:2015-05-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553000802195331
更新日期:2008-07-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530099140645
更新日期:1999-02-01 00:00:00
abstract::Photoirradiation of aqueous solutions of DNA in the presence of Al- or Zn-tetrasulphonated phthalocyanines (AIPcS4 and ZnPcS4) causes formation of strand breaks and liberation of nucleobases. The effect of added D2O, which enhances singlet oxygen (1O2) lifetime, radical scavengers including alcohols and the spin-trap ...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:
更新日期:1994-12-01 00:00:00
abstract:PURPOSE:The LET position of the RBE maximum and its dependence on the cellular repair capacity was determined for carbon ions. Hamster cell lines of differing repair capacity were irradiated with monoenergetic carbon ions. RBE values for cell inactivation at different survival levels were determined and the differences...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530099139232
更新日期:1999-11-01 00:00:00
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pub_type: 杂志文章,评审
doi:10.3109/09553002.2010.522686
更新日期:2011-02-01 00:00:00
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更新日期:2014-03-01 00:00:00
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更新日期:2001-02-01 00:00:00
abstract::The radiation chemistry of the oligomer d(TpApCpG) X-irradiated in aqueous solution containing glutathione was studied. Four products were isolated by HPLC and characterized by NMR spectroscopy. Two of the major products are isomers of a 5-hydroxy-5,6-dihydrothymine modification of d(TpApCpG). A dihydrothymine modific...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/09553009014552141
更新日期:1990-11-01 00:00:00
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journal_title:International journal of radiation biology
pub_type: 杂志文章
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更新日期:2011-02-01 00:00:00
abstract:PURPOSE:Angiotensin-converting enzyme (ACE) inhibitors are effective in the prophylaxis of radiation-induced renal and lung injury. Studies were designed to determine whether blocking the angiotensin II (AII) receptor, rather than blocking AII synthesis with ACE inhibitors, would also be effective. MATERIALS AND METHO...
journal_title:International journal of radiation biology
pub_type: 杂志文章
doi:10.1080/095530098142257
更新日期:1998-04-01 00:00:00