首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Multi-drug resistance (MDR) in MCF7 breast cancer cells and multi-xenobiotic resistance (MXR) in mussel (Mytilus edulis) blood cells (MBC) are well known mechanisms that contribute to the decrease in intracellular concentrations of many unrelated but cytotoxic compounds. In the present work, we have carried out comparative investigations of the MDR/MXR protective mechanisms using a rapid colorimetric assay for cell viability and calcein accumulation for MDR/MXR activities. These studies were performed using cultured MCF7 and MBC before and after in vitro exposure to xenobiotics. Our results indicate that a 5-day exposure to doxorubicin or vincristine decreased calcein accumulation in MBC which is consistent with an induction of multi-xenobiotic resistance. The increase in calcein accumulation provoked by 1-h treatment with 50 microM verapamil was much lower in MBC when compared to the P-glycoprotein overexpressing MCF7 cell line. We conclude that such microplate assays could be used in primary cultures of MBC to estimate the effects of various chemicals on MXR activity.  相似文献   

2.
Early and late developmental stages of grass shrimp embryos were exposed to different concentrations of two genotoxicants, 2-methyl-1,4-naphthoquinone (MNQ) and 4-nitroquinoline-N-oxide (NQO). DNA strand breaks were assessed by the comet assay while embryo development effects were determined by % of embryos hatching. Early embryo stage embryos were significantly more sensitive to genotoxicants than late stages. For example, all stage 4 embryos failed to hatch at 1 microM NQO while 95% of stage 8 hatched at this concentration. High DNA tail moments, which are a measure of the number of DNA strand breaks, were found in late stage embryos exposed to genotoxicants. Early stage embryo development was effected by low concentrations of genotoxicants but no changes were observed in DNA tail moments. We suggest that high DNA moments in late embryo stages reflect high DNA repair activity, while early stages may lack a fully developed DNA repair system.  相似文献   

3.
The multidrug resistance (MDR) mechanism corresponds to a defence system relying on the expression of high molecular membrane proteins that can actively lower the intracellular concentration of a wide variety of toxins, thus maintaining them below their toxic level. Using RT-PCR, expression levels of a gene belonging to the class I of mammalian mdr genes, has been assessed in different developmental stages of the oyster Crassostrea gigas. While no expression was found in the oocyte or the trocophore stage, a rise of mRNA content was observed from the veliger stage to the juvenile stage, thus indicating the induction of the system as the animal is developing in the environment. The incubation of gill fragments in the dye rhodamine B and subsequent measurements of intracellular fluorescence using a microplate reader indicates that the system can effectively decrease the accumulation of the test compound in a competitive manner with known inhibitors or environmental contaminants as observed in vertebrate cells. The oyster MXR system is thus becoming active in adult oyster and could be of importance in environmentally contaminated areas.  相似文献   

4.
To investigate the effects of salinity on early development of Chinese mitten crab ( Eriocheir sinensis ), and the salinity tolerance mechanism of embryos, different developmental stages of embryos (gastrula, eyespot and pre-hatching stage), and hatched stage I zoea and megalopa, were exposed to a range of salinities (1, 5, 10, 15 (control), 20, 25, 30, 35 and 40). Hatching, survival and molting were monitored. Effects of 24-hour hypersaline (35) and hyposaline (1) stress on egg diameter, water content, Na +/K +-ATPase (NKA) activity, and crustacean hyperglycemic hormone (CHH) gene mRNA expression in embryos and megalopa, are reported. Embryos are more tolerant of low (≤ 5) than high (≥25) salinities, with optimum ranges for gastrula and pre-hatching stage embryos being 5-20, and for eyespot embryo and stage I zoea, 10-20. Most megalopa can molt to the first juvenile instar by day 5 at salinities between 1 and 40, whereas molting of megalopa stages was delayed at 40. Hypersaline conditions resulted in a loss of moisture, reduction of egg volume, and a signifi cant increase in NKA activity and CHH mRNA expression at some developmental stages. Hyposaline conditions did not affect moisture content or egg volume, but resulted in decreased NKA activity and CHH mRNA expression in embryos. For megalopa stages, NKA activity was significantly upregulated following both hypo- and hypersaline stress. Our results suggest high salinity will inhibit development and hatching of E. sinensis embryos, and low salinity will affect the survival of their stage I zoea. Increased NKA activity in embryos and megalopa stages might indicate a hyporegulation response under hypersaline conditions. These findings provide useful information for spawning ground protection of indigenous E . sinensis and enrich the knowledge of embryonic tolerance mechanisms of hyperregulating crustaceans following osmotic stress.  相似文献   

5.
A newly standardized 60-minute sea urchin (and sand dollar) sperm bioassay was used to measure the toxicity of sewage at each stage in the treatment process. The sensitivity of the sperm bioassay was compared to the results of 48- to 96-hour bioassays with sea urchin and oyster embryos and crab zoeae in side-by-side tests of each sewage type. These data were then used to estimate the dilutions necessary to protect sensitive life stages of marine animals around a proposed sewage outfall in Puget Sound and to select the best bioassay procedure for a post-discharge program for monitoring water column toxicity.Results showed that very little acute toxicity was removed by the primary treatment process but that toxicity was greatly reduced by secondary treatment. A high degree of toxicity was reintroduced by chlorination but this source of toxicity was essentially eliminated by dechlorination. The simple and rapid sperm assay proved more sensitive to all stages of sewage than did the longer embryo and larval assays. Based on the results of the comparative testing and the ease, rapidity and year-round availability of the sea urchin sperm assay (sea urchins in winter, sand dollars in summer), this test was recommended for post-discharge monitoring of sewage effluent-related toxicity in the receiving waters.  相似文献   

6.
为解析肌肉生长抑制素(Myostatin,MSTN)基因在黄条鰤(Seriola aureovittata)生长发育过程中作用机制。本研究采用cDNA末端快速扩增法,克隆了黄条鰤MSTN基因的全长cDNA序列,采用荧光定量PCR(RT-qPCR)技术对MSTN mRNA在黄条鰤不同组织、胚胎发育过程以及仔稚幼鱼发育过程中的差异表达特征进行了研究。序列分析结果显示,MSTN基因全长cDNA为1828 bp,开放阅读框为1131 bp,编码了376个氨基酸。RT-qPCR分析表明,在检测的脑、垂体、肝脏、肌肉、脾脏、肾脏、鳃、心脏、胃、肠、头肾组织中MSTN mRNA均有表达,其在肌肉中表达量最高(P<0.05)。MSTN mRNA在胚体下包2/3时期至孵化期表达量显著升高,且在孵化期达到峰值(P<0.05)。MSTN mRNA在孵化后3天前表达量显著升高(P<0.05),在第20天降低至较低水平,25天后表达量再次显著升高,在第30天达到峰值(P<0.05)。研究结果首次揭示了MSTN基因在黄条鰤的胚胎及早期生长发育过程中发挥着重要作用,本研究为开展黄条鰤繁养殖、育种提供了理论参考。  相似文献   

7.
Grass shrimp embryos develop in egg sacs (stages 1-10) attached to the female for 14-20 days after which they 'hatch' from the egg sacs into a swimming zoea stage (stage 11). Until they emerge from the egg sacs, embryos depend on lipids and lipovitellin stored within the egg. The percent of embryos which hatch after exposure to toxicants relative to controls was the basis of an embryo development assay. Exposure of embryos to chromium(III) chloride, sodium chromate, mercuric chloride, and 2-methyl-1,2-naphthoquinone (MNQ) resulted in a reduced hatching rate. In addition to effects on embryo development, DNA strand damage tests were carried out on contaminant-exposed embryos, using the single-cell electrophoresis method often referred to as comet assay. Development of stage 4 embryos was more affected by MNQ exposure than stage 7 embryos. The hatching rates of stages 4 and 7 embryos exposed to MNQ (172 micrograms/l) were 0 and 90%, respectively. DNA strand damage, measured as DNA tail moments, were 3.4 and 4.4, respectively. Thus, exposure of an early embryo stage to MNQ prevented full embryo development while development of later embryo stages was not affected. It may be that the DNA repair systems are more efficient in later embryo stages than in early stages and thus DNA damaged in the early stages affects development.  相似文献   

8.
The effects of water-soluble fractions (WSF) of thirteen used ferrochrome lignosulphonate muds on developing embryos of Patiria miniata were studied. The muds were collected during the drilling of a single slant well from Platform Hondo in the Santa Barbara Channel, California, at drilling depths of 4220 to 9858 ft. None of the embryos survived 48 hours' exposure in 25 % WSF of the muds (25,000 ppm mud added (v/v)). Significant reduction in growth and high abnormalities (up to 100%) were observed in the 15% WSF. In lesser concentrations the effects varied from significant reduction of growth, down to 0·5% for three muds, to significant enhancement of growth for several muds in some dilutions. The EC50's ranged from 5% to greater than 15% WSF. In the 5% WSF, decreased embryo growth was correlated with increasing Cr concentrations and possibly also with total organic carbon (TOC). Although experiments carried out with NaOH addition to simulate the strong alkalinity of the muds showed increased abnormalities and decreased embryo growth with increasing pH, in the chemically complex WSF (5% dilution) the opposite effect occurred. Dissociation of chrome lignosulphonate molecules from particulates may occur with increasing acidity and explain the relationship between pH and toxicity in dilute WSF. The results of these experiments are discussed in terms of the effects of dispersions of drilling muds in the oceanic environment. It is concluded that water column effects on organisms during the dumping of such muds are only likely within short distances of the discharge pipes of offshore drill rigs.  相似文献   

9.
In the eastern equatorial Atlantic Ocean, changes in the concentration of carbonate in Late Quaternary sediments resulted from reduced production of carbonate in surface waters and increased dilution with non-carbonate sediments during glacial maxima. During glacial stages, production of carbonate in surface water (measured as its accumulation rate in shallow, undissolved cores) decreased by one half. The glacial accumulation rate of non-carbonate components increased 1.5 to 4 times over Holocene values; the greatest increases occurred in the deepest cores.

Carbonate dissolution during stages 2, 3 and 4 increased the proportion of foraminiferal fragments and decreased the accumulation rate of susceptible species in the deep sites. In shallow sites, slightly increased dissolution can be detected during stage 3 while greatly increased dissolution occurred during stage 4. Bathymetric profiles of foraminiferal fragmentation and accumulation document a shoaling of the foraminiferal lysocline by 1000 m during glacial isotopic stages. We present a mass balance model of sediment accumulation for carbonate and insoluble components and from this model we estimate the rate of downslope transport and dissolution of carbonate at the Sierra Leone Rise. Our results show that during stage 4 the rate of carbonate loss to dissolution was greater than the rate observed today or during other interglacial stages. The calculated rates of dissolution for stages 2 and 3 are not significantly different from those calculated for stage 1.  相似文献   


10.
Tributyltin (TBT) has been widely employed in marine anti-fouling paints as a biocide, although it represents a serious risk, particularly in estuarine and coastal water/sediment ecosystems. In this study, the embryotoxic effects of TBT and its degradation products, dibutyltin (DBT) and monobutyltin (MBT), were analyzed during the development of the sea urchin Paracentrotus lividus from post-fertilization to the pluteus stage, to better clarify ecotoxicological impact. The embryotoxicity of butyltins is concentration-dependent and increases proportionally with number of butyl groups. Significant growth reduction was observed at TBT concentrations as low as 0.01 microgram l-1; 1 microgram l-1 was the maximum concentration allowing embryos to reach the pluteus stage at 48 h post-fertilization. Development was blocked at the morula or blastula stage with higher TBT concentrations. DBT and MBT are less toxic: slowed development and a decrease in pluteus size occurred at 10 micrograms l-1 DBT and 0.5 mg l-1 MBT. Effects on both skeletal deposition and blocked embryonic development are suggested to be due to the interference of organotin compounds with intracellular calcium homeostasis.  相似文献   

11.
The asteroid Patiria miniata was used to develop a static bioassay for various crude oil water-soluble fractions (WSF). The criterion used is the size of 48-h exposed embryos. The reasons for choosing this species and the growth criterion are discussed. Experiments show that the body length of 48-h exposed embryos is inversely proportional to hydrocarbon concentration of the WSF and the time of exposure. It is also shown that the toxicity of the WSF decreases with the age of the preparation and that the first 12 h following fertilisation are most sensitive to the effects of WSF.  相似文献   

12.
利用组织能量密度测定技术和残差指标分析方法, 分析了南海鸢乌贼中型群雄性个体肌肉组织和性腺组织的能量积累及其分配变化过程。结果显示, 胴体、尾鳍、足腕、精荚复合体、精巢等组织的能量密度值分别为21.16±1.44、21.98±1.51、21.44±1.50、20.83±1.70和21.41±1.70kJ?g -1。胴体和精荚复合体两组织的能量密度在不同性腺成熟度之间均存在显著性差异, 而尾鳍、足腕、精巢等3种组织的能量密度则在不同性腺成熟度之间均没有统计学差异。个体总能量积累为299.31±90.81kJ; 随着个体生长, 总能量积累呈现增加的趋势。胴体、足腕和尾鳍等肌肉组织的能量占比为95.31%~98.04%, 随着性腺发育呈现降低的趋势; 精巢和精荚复合体等性腺组织的能量总投入占比为2.63%~5.33%, 随着性腺发育呈增加的趋势, 并在Ⅴ期达到最大值。同时, 残差指标分析显示, 胴体、尾鳍、足腕等肌肉组织能量积累-胴长残差与性腺组织能量积累-胴长残差呈显著的正相关关系, 表明个体性腺发育过程中肌肉组织能量没有转化用于性腺组织的生长发育, 其生殖能量投入倾向于外源性投入。初步掌握了南海鸢乌贼中型群雄性个体肌肉和性腺组织能量的积累变化过程, 为深入了解它们的繁殖策略和为可持续开发利用该种类资源提供了科学基础。  相似文献   

13.
Embryos of the estuarine teleost, Fundulus heteroclitus, were exposed during development to different concentrations of the water-soluble fractions (WSF) of a No. 2 fuel oil under various temperature-salinity combinations. Temperatures and salinities were, respectively: 20, 25 or 30°C and 10, 20 or 30%S. The WSF were extracted from No. 2 fuel oil daily and diluted to concentrations of 15, 20 or 25% of the original mixture. Controls were exposed to seawater without WSF at each temperature-salinity combination.The length of eleutheroembryos was markedly decreased by exposure to WSF. Temperature exerted an effect on growth at low WSF concentrations (0 and 15% WSF) but not at higher ones. The two highest WSF concentrations had a predominant effect on growth that was not further modified by physical factor influences. Conversely, as the WSF exposure increased, the yolk diameter increased, indicating a decreased utilisation of yolk material during development. The mean number of vertebrae in the eleutheroembryos decreased at high WSF concentrations and at high temperatures. Morphological abnormalities consisted predominantly of spinal deformations (scoliosis and lordosis). The data indicate that the survivors of chemical toxicity during embryo development exhibit sublethal responses which would reduce their survival potential in later life.  相似文献   

14.
Using modified clay is one of the most promising methods for the mitigation of harmful algal blooms(HABs).However,the environmental impact of modified clay has become a subject of global concern.In this study,turbot(Scophthalmus maximus L.)embryos were used as a model to assess the effect of modified clay on this sensitive stage of fish development.Results show that the 24 and 48h LC 50(median lethal concentrations)of the modified clay were 1.70 and 1.65 g/L,and the safe concentration was 0.47 g/L,which is much higher than the concentration used to treat HAB.The modified clay did not affect significantly the hatchability of turbot embryos but when the concentration exceeded 0.50 g/L,the deformity rate of newly hatched larvae increased significantly.The total length,specific growth rate(SGR)and yolk sac absorption rate of larvae reached their peaks at 0.50 g/L and then gradually decreased as the concentration of modified clay increased.Therefore,a moderate amount of modified clay does not harm the survival and hatching of turbot embryos,or the growth and development of newly hatched larvae.  相似文献   

15.
双锯鱼(Amphiprion)亦称为海葵鱼,又称为小丑鱼,是一类经济价值较高的海水观赏鱼。目前国内在双锯鱼的胚胎发育、人工饲养以及形态学观察等方面已经取得了有效成果,但在分子生物学水平上对其基因表达的研究较少。为了筛选出适用于双锯鱼胚胎不同发育阶段以及成鱼组织的内参基因,分析酪氨酸酶(TYR)基因的表达情况,以眼斑双锯鱼(A.ocellaris)和白条双锯鱼(A.frenatus)为材料,利用实时定量聚合酶链式反应(qPCR)对18SrRNA、GAPDH(甘油醛-3-磷酸脱氢酶基因)、Ef-1α(转录延伸因子基因)和β-actin(β-肌动蛋白基因)这4个候选内参基因的表达水平进行检测,同时通过geNorm和Norm Finder软件对其稳定性进行评估,最后以合适的内参基因作为参考,研究TYR mRNA的表达水平。结果表明,在双锯鱼胚胎的不同发育阶段,18S和β-actin的表达量相对于其他基因较为稳定;在双锯鱼的不同组织中,稳定性依次为18S>β-actin>Ef-1α>GAPDH。以18S作为内参基因时分析发现TYR基因的表达在双锯鱼胚胎发育过程中呈先上升后下降的趋势,在体节期表达量最高;在双锯鱼各组织中均有表达,且在眼、尾和红皮中表达量最高。  相似文献   

16.
Factors affecting the development of the embryos and production of larvae of the spiny lobster Sagmariasus verreauxi were investigated. Mature lobsters were collected from the fishery in New Zealand and held in captivity until they moulted, mated, and extruded eggs. For females, moulting took place in winter (July/August) and mating occurred 58–88 days later in early spring. The ovigerous females were then held at three temperatures and embryo development monitored at approximately weekly intervals. Mean times to hatch were 55, 75, and 130 days at 20°C, 17°C, and 13°C respectively. The total number of larvae that hatched from each female ranged from 0.97 to 1.4 million. The theoretical temperature at which embryo development ceases (a biological zero) for S. verreauxi, of 9.4°C, was calculated from data on the appearance of the median eye, the eyes and the chromatophores, and the time to hatch. An eye index formula was also derived to allow prediction of time to hatch at a range of temperatures using the cumulative difference between the rearing temperature and the biological zero. First instar phyllosomas from embryos reared at 20°C were significantly smaller than those from 17°C and 13°C but there was no significant difference in fitness. This study shows that hatching can be spread over a number of months, without significantly affecting larval quality, simply by manipulating holding temperature.  相似文献   

17.
Selenium is a potent reproductive and teratogenic environmental contaminant and there are concerns over possible reproductive effects of selenium on the Sacramento splittail (Pogonichthys macrolepidotus) population, a threatened species, in California, USA. In this study, the teratogenic effects of selenium were examined in splittail embryos exposed to 0.0, 5.0, and 15.0 mg l(-1) sodium selenite for 48-h at 18.0 degrees C under static conditions, with renewal every 12 h. Embryo development was evaluated daily for abnormalities from initiation of exposure (stage 27) to initiation of exogenous feeding. At the end of evaluation, prelarvae were preserved for histological analysis. There were no significant differences in mortality or hatching success between control and exposed embryos. Exposed fish had pericardial edema and deformities of skeletal tissues (loss of tail, lordosis, scoliosis, and kyphosis). Other histological alterations were limited to dysplasia, hyperplasia and metaplasia of skeletal tissues in the deformed fish. This study showed that a short exposure of embryos during somite development has significant effects on the musculoskeletal development.  相似文献   

18.
Abstract. Combined effects of temperature, salinity, and metal enrichment (Zn, Mn, Co) on the growth rate and chemical composition of Fucus vesiculosus L. were studied in culture. Factorial combinations of two temperatures and three salinities were used. The results indicated that the accumulation of Zn and Mn into algal tissue was enhanced by dilution of the media, whereas Co accumulation exhibited maxima at the medium salinity. Zn accumulation was enhanced by temperature, while the opposite was true for Mn and Co.
In the presence of metals the usual dilution-induced changes in growth activity and chemical composition of Fucus plants were altered, while responses to the temperature factor remained unchanged. In diluted media, growth activity and mannitol content decreased along with a simultaneous increase of protein content. In the presence of Zn and Mn the mannitol content exhibited peaks at the medium salinity; in the presence of Co the dilution-induced pattern remained unchanged. Salinity-induced changes in growth and protein content were altered in the presence of metals. Maxima in growth rates were found at the medium salinity. Growth was higher in extremely diluted media than in scawater, indicating an inversion of responses to the salinity factor. Both the growth rate and mannitol content were lowest under the influence of Zn.  相似文献   

19.
There is a growing body of evidence to suggest that certain polycyclic aromatic hydrocarbons (PAHs) pose a greater hazard to aquatic organisms than previously demonstrated, due to their potential to cause photo-induced toxicity when exposed to ultraviolet (UV) radiation. The consequences of photo-induced toxicity are reported here for embryo-larval stages of the pacific oyster Crassostrea gigas, following exposure to pyrene and benzo[a]pyrene. During laboratory investigations, significant increases in toxicity were observed in the presence of environmentally attainable levels of UV-radiation, compared with embryos exposed to PAH alone, at levels previously deemed to have little acute biological effect. The phototoxicity of pyrene and benzo[a]pyrene completely inhibited the development to the D-shell larval stage when embryos were simultaneously exposed to 5 microg l(-1) PAH and ultraviolet light (UVB = 6.3 +/- 0.1 microW/cm2 and UVA = 456.2 +/- 55 microW/cm2). A linear relationship was also demonstrated for benzo[a]pyrene phototoxicity with decreasing UV light intensity.  相似文献   

20.
The multixenobiotic resistance (MXR) mechanism, mediated by activity of the transmembrane P-glycoprotein, represents a basic biological defence system in aquatic organisms. Here we investigate the MXR transport activity in an aquatic vertebrate, the common carp (Cyprinus carpio). We measured the accumulation rate of a model MXR substrate, the fluorescent dye rhodamine B (RB), in gills, lateral muscles, liver and bile. Results obtained using this method showed a significant increase of RB accumulation in tissues of fish exposed for I h to 3 microM RB in the presence of the model MXR inhibitors cyclosporin A (CA, 5 microM) or verapamil (VER, 10 microM), when compared with specimens exposed without inhibitors. The highest increase in RB accumulation detected in the liver (VER 54%, CA 170%) indicates that among the tissues analysed within this study, liver is the most prominent candidate organ for the functional detection of MXR activity in C. carpio.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号