Winter Temperature and UV Are Tightly Linked to Genetic Changes in the p53 Tumor Suppressor Pathway in Eastern Asia

The tumor suppressor p53 is a master sensor of stress. Two human-specific polymorphisms, p53 codon 72 and MDM2 SNP309, influence the activities of p53. There is a tight association between cold winter temperature and p53 Arg72 and between low UV intensity

Single UV excitation of Hoechst 33342 and propidium iodide for viability assessment of rhesus monkey spermatozoa using flow cytometry

Many fluorescent probes excited by visible light have been used to assess sperm quality by flow cytometry. Developing a viability evaluation method using UV excited stains would be useful for multiparameter analysis of sperm function. This investigation was conducted to determine the efficacy of Hoechst 33342 (H342) and propidium iodide (PI) dual staining for evaluating rhesus monkey sperm viability through use of flow cytometry and excited by a single UV laser. The results showed that the live cells stained only with H342 strongly correlated with expected sperm viability, and flow cytometric analyses were highly correlated with fluorescence microscopic observation. Using H342/PI/SYBR-14 triple staining method, it was found that the live/dead sperm distributions were completely concordant in both H342/PI and SYBR-14/PI assays. In addition, this dual staining was extended with fluorescein isothiocyanate-conjugated peanut agglutinin (FITC-PNA) to simultaneously analyze viability and acrosome integrity of sperm cryopreserved using two different extenders, TTE and TEST, and indicated that TTE offered better Preservation of plasma and acrosome integrity than TEST Therefore, the H342/PI dual staining provides an accurate technique for evaluating viability of rhesus monkey sperm and should be valuable for multiparameter flow cytometric analysis of sperm function.

增强UV-B辐射下一氧化氮对小球藻氮素代谢和类囊体的保护作用

由于到达地球表面的紫外线B辐射不断加强,生物生长受到了威胁。UV-B的增强改变了生物体赖以生存的环境,影响了藻类生物生长,抑制了其光合作用。以BG11为培养基,在室内培养的条件是光照强度为60μmol·m-2s-(1昼夜比为12h∶12h),温度为26℃,研究了一氧化氮(NO)在增强UV-B(强度为0.2J·m-2s-1)辐射下的对小球藻的作用。测定了小球藻的硝酸还原酶(NR,nitrate reductase)、亚硝酸还原酶(NiR,nitrite reductase)、谷胱甘肽还原酶(GS,gluta

UV/TiO_2薄膜体系光降解酞酸酯研究

采用自制玻璃负载TiO2薄膜,研究了UV-V is/TiO2以及UV/TiO2/H2O2体系对2种酞酸酯DBP和DEHP的光催化降解情况。研究结果表明,TiO2在暗处对酞酸酯没有降解作用;UV/TiO2体系能有效光降解DBP和DEHP,TiO2具有明显的光催化作用,增强因子分别为fDBP=2.06,fDEHP=1.53;在一定浓度范围内DBP在UV/TiO2体系中的降解速率与其初始浓度成负一级动力学关系;UV/TiO2/H2O2体系对DBP的光降解能力远大于UV/TiO2和UV/H2O2体系,H2O2能显

UV/H_2O_2体系光降解邻苯二甲酸二丁酯研究

研究了邻苯二甲酸二丁酯(DBP)在UV/H2O2体系中的光降解。结果表明:DBP在UV/H2O2体系中能很好地降解,且其光降解速率大于在单一UV辐照下的光降解速率;在pH为中性条件下DBP的光降解速率最快,而在强酸性或碱性条件下DBP的光降解速率均较低;在一定H2O2浓度范围内,DBP的光降解速率随c(H2O2)的升高而增大,但当c(H2O2)过高时,其对.OH自由基的清除作用使DBP的光降解速率减慢。DBP的光降解速率随其初始质量浓度的增大而降低;在实验质量浓度范围内,DBP的光降解速率常数近似与其初始

UV-B-induced Oxidative Damage and Protective Role of Exopolysaccharides in Desert Cyanobacterium Microcoleus vaginatus

UV-B-induced oxidative damage and the protective effect of exopolysaccharides (EPS) in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity (Fv/Fm), cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species (ROS) generation, malondialdehyde (MDA) production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UV-B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase (SS) activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.

Enhanced protection against oxidative stress in an astaxanthin-overproduction Haematococcus mutant (Chlorophyceae)

Many unicellular green algae can become yellow or red in various natural habitats due to mass accumulation of a secondary carotenoid, such as lutein, or astaxanthin. The accumulation of secondary carotenoids is generally thought to be a survival strategy of the algae under photo-oxidative stress or other adverse environmental conditions. The physiological role of the carotenoids in stress response is less well understood at the subcellular or molecular level. In this study, a stable astaxanthin overproduction mutant (MT 2877) was isolated by chemical mutagenesis of a wild type (WT) of the green microalga Haematococcus pluvialis Flotow NIES-144. MT 2877 was identical to the WT with respect to morphology, pigment composition, and growth kinetics during the early vegetative stage of the life cycle. However, it had the ability to synthesize and accumulate about twice the astaxanthin content of the WT under high light, or under high light in the presence of excess amounts of ferrous sulphate and sodium acetate. Under stress, the mutant exhibited higher photosynthetic activities than the WT, based on considerably higher chlorophyll fluorescence induction, chlorophyll autofluorescence intensities, and oxygen evolution rates. Cell mortality caused by stress was reduced by half in the mutant culture compared with the WT. Enhanced protection of the mutant against stress is attributed to its accelerated carotenogenesis and accumulation of astaxanthin. Our results suggest that MT 2877, or other astaxanthin overproduction Haematococcus mutants, may offer dual benefits, as compared with the wild type, by increasing cellular astaxanthin content while reducing cell mortality during stress-induced carotenogenesis.

Effects of solar UV radiation on diurnal photosynthetic performance and growth of Gracilaria lemaneiformis (Rhodophyta)

Previous studies on diurnal photosynthesis of macroalgal species have shown that at similar levels of photosynthetically active radiation (PAR, 400-700nm) the photosynthetic rate is lower in the afternoon than in the morning. However, the impacts of solar ultraviolet radiation (UVR, 280-400nm) have been little considered. We investigated the diurnal photosynthetic behaviour of the economically significant red alga Gracilaria lemaneiformis in the absence or presence of UV-A+B or UV-B with a flow-through system. While UV-A and UV-B, respectively, inhibited noontime Pmax by 22% and 14% on the sunny days, UV-A during sunrise (PAR below about 50Wm-2) increased the net photosynthesis by about 8% when compared with PAR alone. UV-A + PAR also resulted in higher apparent photosynthetic efficiency in the morning than in the afternoon period than PAR alone. Nevertheless, integrated daytime photosynthetic production under solar PAR alone was higher than with either PAR + UV-A+B or PAR + UV-A. Relative growth rate in the long term (9 days) matched the integrated photosynthetic production in that UV-A led to 9-15% and UV-B to 19-22% reduction, respectively. UV-absorbing compounds were found to be higher in the thalli exposed to PAR+UV-A+B than under PAR alone, reflecting a protective response to UVR.

Photosynthesis and growth of Arthrospira (Spirulina) platensis (Cyanophyta) in response to solar UV radiation, with special reference to its minor variant

The minor variant of the economically important cyanobacterium, Arthrospira platensis, usually appears in commercial production ponds under solar radiation. However, how sensitive the minor variant to solar UVR and whether its occurrence relates to the solar exposures are not known. We investigated the photochemical efficiency of PSII and growth rate of D-0083 strain and its minor variant in semi-continuous cultures under PAR (400-700 nm) alone, PAR + UV-A (320-400 nm) and PAR + UV-A + UV-B (280-700 nm) of solar radiation. The effective quantum yield of D-0083 at 14:00 p.m. decreased by about 86% under PAR, 87% under PAR + UV-A and 92% under PAR + UV-A + UV-B (280-315 nm), respectively. That of the minor variant was reduced by 93% under PAR and to undetectable values in the presence of UV-A or UV-A + UV-B. Diurnal change of the yield showed constant pattern during long-term (10 days) exposures, high in the early morning and late afternoon but the lowest at noontime in both strains, with the UVR-related inhibition being always higher in the variant than D-0083. During the long-term exposures, cells of D-0083 acclimated faster to solar UV radiation and showed paralleled growth rates among the treatments with or without UVR at the end of the experiment; however, growth of the minor variant was significantly reduced by UV-A and UV-B throughout the period. Comparing to the major strain D-0083, the minor variant was more sensitive to UVR in terms of its growth, quantum yield and acclimation to solar radiation. (c) 2007 Elsevier B.V. All rights reserved.

Effects of solar UV radiation on germination of conchospores and morphogenesis of sporelings in Porphyra haitanensis (Rhodophyta)

The effects of ultraviolet radiation (UVR 280-400 nm) on the germination of Porphyra haitanensis conchospores and on the growth and morphogenesis of the subsequent sporelings were investigated by culturing the released conchospores under natural sunlight from 29 September to 6 October 2005. Germination increased with time and was faster when UV-B was excluded using cut-off filters. There were significant negative effects of UV-B radiation on growth and cell division of sporelings, with decreases up to 18% for thallus length, between 6 and 18% for thallus width, up to 29% for thallus area, and between 6 and 14% for cell size as compared to PAR-controls. UV-A had a significant positive effect on morphogenesis, enhancing the formation of sporelings with cells dividing transversely; on the other hand, UV-B delayed the formation of such sporelings. We also tested the effects of solar UVR on the growth of P. haitanensis juveniles and found no significant effects. Our results indicate that UV-A has an important role in the germination and morphogenesis of the species, but on the other hand, sporelings of P. haitanensis are more sensitive to UV-B radiation than juveniles.

Solar UV radiation drives CO2 fixation in marine phytoplankton: A double-edged sword

Photosynthesis by phytoplankton cells in aquatic environments contributes to more than 40% of the global primary production (Behrenfeld et al., 2006). Within the euphotic zone (down to 1% of surface photosynthetically active radiation [PAR]), cells are exposed not only to PAR (400-700 nm) but also to UV radiation (UVR; 280-400 nm) that can penetrate to considerable depths (Hargreaves, 2003). In contrast to PAR, which is energizing to photosynthesis, UVR is usually regarded as a stressor (Hader, 2003) and suggested to affect CO2-concentrating mechanisms in phytoplankton (Beardall et al., 2002). Solar UVR is known to reduce photosynthetic rates (Steemann Nielsen, 1964; Helbling et al., 2003), and damage cellular components such as D1 proteins (Sass et al., 1997) and DNA molecules (Buma et al., 2003). It can also decrease the growth (Villafane et al., 2003) and alter the rate of nutrient uptake (Fauchot et al., 2000) and the fatty acid composition (Goes et al., 1994) of phytoplankton. Recently, it has been found that natural levels of UVR can alter the morphology of the cyanobacterium Arthrospira (Spirulina) platensis (Wu et al., 2005b). On the other hand, positive effects of UVR, especially of UV- A (315-400 nm), have also been reported. UV- A enhances carbon fixation of phytoplankton under reduced (Nilawati et al., 1997; Barbieri et al., 2002) or fast-fluctuating (Helbling et al., 2003) solar irradiance and allows photorepair of UV- B-induced DNA damage (Buma et al., 2003). Furthermore, the presence of UV-A resulted in higher biomass production of A. platensis as compared to that under PAR alone (Wu et al., 2005a). Energy of UVR absorbed by the diatom Pseudo-nitzschia multiseries was found to cause fluorescence (Orellana et al., 2004). In addition, fluorescent pigments in corals and their algal symbiont are known to absorb UVR and play positive roles for the symbiotic photosynthesis and photoprotection (Schlichter et al., 1986; Salih et al., 2000). However, despite the positive effects that solar UVR may have on aquatic photosynthetic organisms, there is no direct evidence to what extent and howUVR per se is utilized by phytoplankton. In addition, estimations of aquatic biological production have been carried out in incubations considering only PAR (i. e. using UV-opaque vials made of glass or polycarbonate; Donk et al., 2001) without UVR being considered (Hein and Sand-Jensen, 1997; Schippers and Lurling, 2004). Here, we have found that UVR can act as an additional source of energy for photosynthesis in tropical marine phytoplankton, though it occasionally causes photoinhibition at high PAR levels. While UVR is usually thought of as damaging, our results indicate that UVR can enhance primary production of phytoplankton. Therefore, oceanic carbon fixation estimates may be underestimated by a large percentage if UVR is not taken into account.

Determinations of residual furazolidone and its metabolite, 3-amino-2-oxazolidinone (AOZ), in fish feeds by HPLC-UV and LC-MS/MS, respectively

The antibacterial drug furazolidone belonging to the group of nitrofuran antibacterial agents has been widely used as an antibacterial and antiprotozoal feed additive for poultry, cattle, and farmed fish in China. During application a large proportion of the administered drug may reach the environment directly or via feces. Although the use of furazolidone is prohibited in numerous countries, there are indications of its illegal use. It is known that furazolidone can be rapidly metabolized to 3-amino-2-oxazolidinone (AOZ) in the body of the target organism. In this study, a total of 21 fish feed samples, including 17 commercial fish feeds from local markets in China (representing 15 different formulations) and 4 fish feeds obtained from Germany and Turkey, respectively, are analyzed to determine whether the drug is still illegally used or commercially available feeds are contaminated by this drug. High-performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) methods have been implemented to determine furazolidone and its metabolite AOZ in fish feeds containing animal protein, respectively. An efficient and convenient cleanup method for the determination of furazolidone in fish feeds is developed, and a simple cleanup method for the determination of AOZ is used. Method recoveries for samples used were determined as 87.7-98.3% for furazolidone at two spike levels of 2.0 and 5.0 ng g(-1) and as 95.6-102.8% for AOZ at spike levels of 0.4 and 0.8 ng g(-1). Limits of detections were 0.4 ng g(-1) for furazolidone and 0.05 ng g(-1) for AOZ. The established methods are therefore suitable for the determination of furazolidone and its metabolite AOZ in fish feeds at trace contamination levels. Using the established methods, all fish feed samples have been proved to be furazolidone negative; however, AOZ is tested in 16 of 17 fish feeds obtained from local markets in the Hubei province of China, with a positive rate as high as 94.1%.

Sorption, degradation and mobility of microcystins in Chinese agriculture soils: Risk assessment for groundwater protection

In the present paper, sorption, persistence, and leaching behavior of three microcystin variants in Chinese agriculture soils were examined. Based on this study, the values of capacity factor and slope for three MCs variants in three soils ranged from 0.69 to 6.00, and 1.01 to 1.54, respectively. The adsorption of MCs in the soils decreased in the following order: RR > Dha(7) LR > LR. Furthermore, for each MC variant in the three soils, the adsorption rate in the soils decreased in the following order: soil A > soil C > soil B. The calculated half-time ranged between 7.9 and 17.8 days for MC-RR, 6.0-17.1 days for MC-LR, and 7.1-10.2 days for MC-Dha(7) LR. Results from leaching experiments demonstrated that recoveries of toxins in leachates ranged from 0-16.7% for RR, 73.2-88.9% for LR, and 8.9-73.1% for Dha 7 LR. The GUS value ranged from 1.48 to 2.06 for RR, 1.82-2.88 for LR, and 1.76-2.09 for Dha(7) LR. Results demonstrated the use of cyanobacterial collections as plant fertilizer is likely to be unsafe in soils. (c) 2006 Elsevier Ltd. All rights reserved.

Photoreduction of mercuric salt in UV/Fe (III)-oxalate complex system

In this paper, the photochemical reduction process of Hg (II) in aqueous solution containing ferric iron and oxalate (Ox) has been studied. Under the radiation of a low-pressure mercury lamp (lambda = 253.7 nm, 8W), Fe(III)-oxalate complexes undergo photolysis to produce ferrous ions and other organic reductive species, which reduce Hg(II) subsequently. For 0.1 mg/L Hg (II), the photoreduction efficiency is comparatively higher in the solution at pH 5.0 than that over the range of 3.0 similar to 8.0. The photoreduction efficiency of Ho (II) in aqueous solution increases with increasing, initial concentration of ferric ions from 0.02 mmol/L to 0.2 mmol/L and initial concentration of oxalate from 0.96 mmol/L to 4.8 mmol/L and then gradually approaches to a steady state. CH3OH also contributes the reduction of Hg (II). We investigate the increase of the ferric, oxalate and CH3OH concentrations resulting from the increase of reduction efficiency of Hg (II). It can be seen that ferrous ions and other reactive species are reductants of Hg (II), and the reaction product with oxalate is mainly volatile metallic mercury.

Identification of two novel interferon-stimulated genes from cultured CAB cells induced by UV-inactivated grass carp hemorrhage virus

Interferon (IFN) exerts its antiviral effect by inducing the expression of a number of IFN-stimulated genes (ISGs) to establish a host antiviral state. Earlier studies identified some important fish IFN system genes from IFN-induced CAB cells (crucian carp Carassius auratus L. embryonic blastulae cells) after treatment with UV-inactivated GCHV (grass carp hemorrhage virus). Herein, the cloning of 2 novel IFN-stimulated genes, termed Gig1 and Gig2, is described for the same cell system. The complete cDNA sequences of Gig1 and Gig2 contain 1244 bp encoding for a 194-amino-acid protein and 693 bp for a 158-amino-acid protein, respectively. A search of public databases revealed that these are 2 novel IFN-stimulated genes, since neither significant homologous genes nor conserved motifs were identified. Active GCHV, UV-inactivated GCHV and CAB IFN-containing supernatant (ICS) induced transcription of these genes and distinct kinetics were observed. An analysis of differences in expression between the 2 genes and the IFN signal factors CaSTAT1 and CaIRF7 indicated that GCHV infection activated different signal pathways for their up-regulation. Upon virus infection, the transcription of Gig1 but not of Gig2 is strongly suppressed by cycloheximide (CHX). In contrast, following treatment with CAB IFN-containing supernatant, CHX does not inhibit either gene transcription. The results suggest that GCHV infection can induce expression of both Gig1 and Gig2 via newly synthesized CAB IFN, most probably through the JAK-STAT signal pathway, and can also directly activate Gig2 transcription without ongoing protein synthesis.