共查询到20条相似文献,搜索用时 31 毫秒
1.
R.J. Pentreath 《Journal of experimental marine biology and ecology》1973,12(3):315-326
The accumulation of 59Fe and 58Co from water by plaice (Pleuronectes platessa L.) has been studied in tissues, and their levels of accumulation related to stable element concentrations. The retention of both radionuclides from labelled Nereis and labelled pellets has also been examined, and the loss of activity from intraperitoneal injections followed over a three-month-period. Biological half-times of the exchange with water have been calculated for many organs, although the rate of accumulation for some tissues could only be expressed as a linear function; however, for both radionuclides the direct accumulation from water resulted in concentration factors of less than 1 % of the values inferred from the stable element data. The relevance of such observations to heavy metal pollution at the higher trophic levels is discussed. 相似文献
2.
R.J. Pentreath 《Journal of experimental marine biology and ecology》1973,12(3):327-334
The accumulation of 65Zn and 54Mn from water by the thornback ray, Raja clavata L., has been studied at tissue level and their levels of accumulation have been related to stable element concentrations. The accumulation of 58Co and 59Fe has also been studied on a whole body basis and comparisons have been made of the 59Fe levels in the tissues after 84 days with those of the stable element. It was found that lower values of accumulation of the radionuclides were obtained than in the case of the teleost Pleuronectes platessa L.. Such differences are discussed in relation to the relative permeabilities of the two species to sea water and the relative ratios of the radionuclides from sea water to blood plasma, and of blood plasma to organ. It is concluded that for both species direct input from water plays only a minor rôle in the accumulation of the four radionuclides studied. 相似文献
3.
R.J. Pentreath 《Journal of experimental marine biology and ecology》1976,25(2):131-140
The accumulation of inorganic and organic mercury by the thornback ray has been studied using 203HgCl2 and CH3203HgCl. Observations have been made on the rates of intake and loss of 203Hg, from both labelled food and sea water, and the internal distributions of the isotope compared with that of total mercury. Both forms were readily absorbed from sea water. Retention of the two forms from food was, however, dissimilar in that, in contrast to inorganic mercury, methylmercury was readily absorbed and only slowly eliminated. The results are compared with data on the accumulation of mercury by the plaice. 相似文献
4.
S.K. Moloo 《Journal of insect physiology》1977,23(4):491-495
After U14C leucine or U14C valine injections into haemolymph of adult female Glossina morsitans during late pregnancy, radioactivity was detected in the post-parturient female and its larval offspring in the injected material, lipids, and a range of non-essential amino acids. The level of radioactivity recorded from the third instar larva was higher than that remaining in the injected adult, and the activity was higher in amino acids than in the lipid fraction. Radiometric analysis of oöcyte and intra-uterine progeny 24 hr after haemocoelic administration to females of labelled leucine or valine revealed a pattern of radioactivity coincident with growth characteristics of these young stages. Rate of leucine uptake by the in utero third instar larva was slightly higher than that of valine, and this instar continues feeding even only a few hours before parturition. For both labelled materials, expired carbon dioxide and excreta from remales in early pregnancy showed significantly higher radioactivity than those in late pregnancy. Uric acid is the main nigrogenous waste of leucine and valine metabolism, though small amounts of these amino acids are also lost during excretion, with valine elimination being higher than leucine. 相似文献
5.
Hazrat Ali 《人类与生态风险评估》2018,24(8):2101-2118
Contamination of freshwater bodies and consequently freshwater fish with toxic heavy metals is a serious environmental issue. The trophic transfer of potentially toxic heavy metals in the human food chains, especially in fish has important implications for human health. The present research study was designed to assess the concentrations of the heavy metals Cr, Ni, Cd, and Pb in the water, sediments, and different freshwater fish species of River Kabul, Pakistan. The heavy metals were quantified in the samples with Atomic Absorption Spectrophotometer. Heavy metal contamination in fish muscles was characterized in terms of metal pollution index and biota-sediments accumulation factor, while human health risk was assessed through calculation of estimated weekly intake. The average concentrations of Cr, Ni, Cd, and Pb in muscle samples of the analyzed fish species at different sampling sites of the river ranged from 12.3 to 33.0, 33.2 to 109.2, 0.98 to 1.5, and 13.9 to 29.6 mg kg?1 wet weight, respectively. Based on the current study data, consumption of the analyzed freshwater fish species from River Kabul was generally safe in terms of potential risk from Cd and Pb but the observed Ni accumulation may pose a potential health risk to regular/excessive fish consumers. 相似文献
6.
R.J. Pentreath 《Journal of experimental marine biology and ecology》1976,24(2):103-119
The accumulation of inorganic mercury from sea water by plaice eggs, larvae, and adult fish has been studied using 203HgCl2 as a tracer. The isotope was rapidly accumulated and the levels of accumulation have been related to stable element concentrations. High concentration factors were attained by many organs, but the distribution of the 203Hg was markedly different from that of the stable element. Whereas the largest fraction of the body burden of mercury is contained by muscle, only a slow rate of accumulation into this tissue was observed. In addition, the mercury in fish muscle is of the methyl form: no evidence for the methylation of the tracer was obtained. 相似文献
7.
61Cr-labelled culture forms of Trypanosoma cruzi were used in antibody titrations of normal and immune rabbit sera. Instead of visually estimating the degree of agglutination of parasites in the post-incubation pellet, the amount of 51Cr-label in unagglutinated trypanosomes in the supernatant was measured. In timed studies it was determined that sedimentation rates of antibody agglutinated and autoagglutinated parasites were sufficiently different to allow measurement of the activity of antibody even in low concentrations. Although the normal rabbit serum contained significant ‘natural’ antibody activity, measurement of labelled, unagglutinated parasites allowed a clear discrimination between the normal and immune serum. It is suggested that the assay may be adaptable to other protozoan parasites and that the procedure offers several advantages over visual estimations of degree of agglutination for end-point titrations. 相似文献
8.
M. U. Khandaker Kh. Asaduzzaman S. M. Nawi A. R. Usman Y. M. Amin E. Daar D. A. Bradley H. Ahmed A. A. Okhunov 《PloS one》2015,10(6)
The environment of the Straits of Malacca receives pollution as a result of various industrial and anthropogenic sources, making systematic studies crucial in determining the prevailing water quality. Present study concerns concentrations of natural radionuclides and heavy metals in marine fish (Rastrelliger kanagurta) collected from the Straits of Malacca, since aquatic stock form an important source of the daily diet of the surrouding populace. Assessment was made of the concentrations of key indicator radionuclides (226Ra, 232Th, 40K) and heavy metals (As, Mn, Fe, Cr, Ni, Zn, Cu, Co, Sr, Al, Hg and Pb) together with various radiation indices linked to the consumption of seafish. The annual effective dose for all detected radionuclides for all study locations has been found to be within UNSCEAR acceptable limits as has the associated life-time cancer risk. The overall contamination of the sampled fish from heavy metals was also found to be within limits of tolerance. 相似文献
9.
B.M. Fung James L. McAdams 《Biochimica et Biophysica Acta (BBA)/General Subjects》1976,451(1):313-320
2H and 31P spin-lattice relaxation times (T1) were studied for invented egg phosphatidylcholine micelles in CCl4 as functions of 2H2O concentration. When the 2H2O/phosphatidylcholine mole ratio changed from 1.0 to 18.0, T1 of 31P increased by about 2.6 fold, whereas T1 of 2H increased by about 50 fold. A quantitative analysis of the deuterium T1 data showed that there is only one water molecule tightly bound to the polar head, and it is in rapid exchange with the rest of the water molecules. The activation energy for the deuterium T1 was 7.1 ± 0.8 kcal/mol (30 ± 3 kJ/mol), and was independent of the 2H2O concentration. 相似文献
10.
Peter R. Allegrini Guus van Scharrenburg Gerard H. De Haas Joachim Seelig 《生物化学与生物物理学报:生物膜》1983,731(3):448-455
1-Palmitoyllysophosphatidylcholine has been mixed in equimolar amounts with specifically deuterated palmitic acid and the structural properties of the lipid/water phase have been studied by 2H- and 31P-nuclear magnetic resonance. The order profile of the free palmitic acid is very similar to that of the parent compound at temperatures above the gel-to-liquid crystal phase transition. The bending of the chain which is typical for diacyl lipids is not observed for the free palmitic acid. The mixture of lysolipid and palmitic acid exhibits well-defined quadrupole splittings even at temperatures below the gel-to-liquid crystal phase transition. Hence it is possible for the first time to establish an order profile in the gel-state of the lipid bilayer phase. Between carbon atoms 5 to 12 the palmitic acid chain is found to assume the extended all-trans conformation with a very small contribution from gauche defects. Towards the methyl terminal a distinct increase in the gauche probability can be noted. The motion of the phosphocholine headgroup was also studied by 2H- and 31P-NMR using selectively deuterated 1-palmitoyllysophosphatidylcholine. The headgroup has a considerably larger motional freedom in the mixture of lysolipid and palmitic acid than in . In addition, the average headgroup conformations are also different in the two systems. 相似文献
11.
Considering water pollution as a potential threat to some endemic cichlids of Lake Barombi Mbo, Cameroon, an investigation was done in 2011 to determine trace metals in its water, linking their uptake in gills and liver of fish to water chemistry. ICP-MS and ICP-OES analyses of trace metals based on total concentration of unfiltered lake water samples showed the presence of trace metals. All fish species accumulated Al, Mn and Sr in the highest concentrations in their gills, with Cu, Cd, Co, Cr, Pb and U highest in the liver. Pungu maclareni accumulated Al, Cr, Co, Sr and Pb in the highest concentrations. The highest mean gill Al concentration of 140 µg g?1 dry weight was measured in P. maclareni gills, this being one of the critically endangered cichlids of the lake. Stable isotope analyses of carbon δ13C and nitrogen δ15N showed that P. maclareni had the highest mean δ13C (?30.2‰) and highest concentrations of Cr, Co, Pb and U in liver, probably linking the carbon source to the accumulation of metals. Though trace metal levels in the lake water were low, their presence in fish tissues suggest they are bioavailable, bioaccumulate and may pose a threat to the aquatic biota, and therefore should be monitored. 相似文献
12.
BackgroundFish are an important source of nutrition for humans. Artisanal fishing plays a fundamental role in Brazil fish production. In Brazil, the unrestrained increase, diffusion, and little importance for environmental causes of other economic activities, such as the agricultural industry, has caused irreparable damage, leading to the contamination of water bodies. Among the countless pollutants that reach water bodies, trace metals are extremely problematic. Here, we evaluated the bioaccumulation and health risk of trace metal contamination in the musculature of the trahira fish (Hoplias malabaricus), collected from two rivers in southeastern Brazil.MethodsDuring the period from May 2017 to November 2019, 90 fish were collected, 45 from each river. River water samples were also taken during the same collection periods. From fish, muscle tissue samples were taken, and together with river water samples, analyzed for the recovery of trace metals (Al, Cr, Mn, Fe, Ni, Cu, As, Cd, and Pb) through the technique of Inductively Coupled Plasma Mass Spectrometry (ICP-MS).ResultsIn general, fish as well as the waters of the Jacaré-Guaçú River had higher concentrations of metals. The elements Al, Cr and Cd stood out from the others analyzed metals for having a hazard index (HQ) above 1 (Al), for being up to 10 times above the concentrations allowed by Brazilian legislation (Cr) and for having a high bioconcentration factor (Cd), indicating a biomagnification process through the food chain.ConclusionIn general, trace metal concentrations in the waters and fish of the Jacaré‐Guaçú were higher than in the Jacaré-Pepira, which shows that the Jacaré‐Guaçú is the one that suffers more anthropogenic action between the two rivers. In addition, some elements such as Al, Cr and Cd, due to its high concentrations, should receive some attention as they can pose risks to the health of fish, which can jeopardize the survival of their populations, and especially to humans who use these animals as a food source. 相似文献
13.
The bioaccumulation and biomagnification of mercury (Hg) and selenium (Se) were investigated in sub-tropical freshwater food webs from Burkina Faso, West Africa, a region where very few ecosystem studies on contaminants have been performed. During the 2010 rainy season, samples of water, sediment, fish, zooplankton, and mollusks were collected from three water reservoirs and analysed for total Hg (THg), methylmercury (MeHg), and total Se (TSe). Ratios of δ13C and δ15N were measured to determine food web structures and patterns of contaminant accumulation and transfer to fish. Food chain lengths (FCLs) were calculated using mean δ15N of all primary consumer taxa collected as the site-specific baseline. We report relatively low concentrations of THg and TSe in most fish. We also found in all studied reservoirs short food chain lengths, ranging from 3.3 to 3.7, with most fish relying on a mixture of pelagic and littoral sources for their diet. Mercury was biomagnified in fish food webs with an enrichment factor ranging from 2.9 to 6.5 for THg and from 2.9 to 6.6 for MeHg. However, there was no evidence of selenium biomagnification in these food webs. An inverse relationship was observed between adjusted δ15N and log-transformed Se:Hg ratios, indicating that Se has a lesser protective effect in top predators, which are also the most contaminated animals with respect to MeHg. Trophic position, carbon source, and fish total length were the factors best explaining Hg concentration in fish. In a broader comparison of our study sites with literature data for other African lakes, the THg biomagnification rate was positively correlated with FCL. We conclude that these reservoir systems from tropical Western Africa have low Hg biomagnification associated with short food chains. This finding may partly explain low concentrations of Hg commonly reported in fish from this area. 相似文献
14.
Laurent D. Labeyrie Jean Claude Duplessy 《Palaeogeography, Palaeoclimatology, Palaeoecology》1985,50(1):217-240
Detailed records of the carbon and oxygen isotopic ratios of Neogloboquadrina pachyderma are compared between nine high-latitude sediment cores, from the Northern and Southern Hemispheres, covering the last 140 000 yrs. The strong analogies between the δ13C records permit to define a δ13C stratigraphic scale, with three clear cut transitions simultaneous with the oxygen isotopic transitions 6/5 (125 kyrs.), 5/4 (65 kyrs.), and 2/1 (13 kyrs.). The δ13C records of N. pachyderma in the high-latitude cores, which follow the changes in δ13C of the surface water TCO2 near areas of deep water formation present trends similar to the benthic foraminifera δ13C records in cores V19–30 and M12-392, although amplitudes of the isotopic shifts are different. This implies that a large part of the observed variations represents global changes in the carbon distribution between biosphere and ocean.The 13C/12C ratios of N. pachyderma in the North Atlantic cores display larger regional variations at 18 kyrs. B.P. than at present. To explain these differences, we have plotted the 18 kyrs. B.P. δ13C values of N. pachyderma from 17 cores distributed N of 40°N. Comparison with published surface water temperature distribution at 18 kyrs. B.P. indicates that a strong divergent cyclonic cell, centered approximatively 55°N and 15°W, was active during most of the last ice-age maximum This hydrology, analogous to the present Weddell Sea, explains the published evidences of bottom water formation, if located on the northern flank of the gyre, and the strong polar front on the southern flank, probable location of intermediate water formation. 相似文献
15.
黄河口盐地碱蓬湿地土壤-植物系统重金属污染评价 总被引:6,自引:0,他引:6
以黄河口盐地碱蓬湿地为例,评价了淹水和非淹水区湿地表层土壤As、Cd、Cu、Cr、Pb和Zn 6种重金属的污染程度及其在土壤-植物系统中的迁移、富集特征,分析了不同积水深度和土壤理化性质对研究区土壤重金属含量的影响.研究结果表明,与土壤或沉积物质量标准相比,黄河口盐地碱蓬湿地土壤受As和Cd污染最严重,而其它重金属污染较轻;非淹水土壤Cd、Cr和Zn含量高于淹水湿地,而As、Cu和Pb则较低;而且淹水土壤As含量随积水深度增加而呈下降趋势,但积水深度对其他重金属含量的影响不明显.相关性分析结果表明,按照受土壤关键影响因子的不同重金属(除As外)可以分为两类:第一类为Cd、Cr和Zn,这些重金属含量受土壤pH值和盐分影响较大,且相互间存在显著正相关关系,表明它们可能有相同的来源;第二类为Pb和Cu,它们受土壤pH值、盐分和有机质的影响,且Pb和Cu之间存在显著正相关关系.除Cr、Cu和Zn外,重金属在盐地碱蓬的根系内一般不发生显著富集,但绝大多数重金属都表现出地上部分的含量比根系更高的现象. 相似文献
16.
J. Lavorel 《BBA》1973,325(2):213-229
The decay of luminescence in the 6–600-μs range following a microsecond flash has been studied in Chlorella. The decay is highly polyphasic; three kinetic components are outlined, in confirmation of the results of K. L. Zankel (1971, Biochim. Biophys. Acta 245, 373–385).Extrapolation of the decay to zero dark time suggests that a unique metastable species C?+, resulting from photochemical charge separation in the System II reaction center, is the substrate of the recombination reaction which gives rise to luminescence.The fast (5–10 μs) and medium (50–70 μs) phases of the decay denote different stabilization steps, preceding relaxation of the centers by electron and proton transduction to the photosynthetic chain.NH2OH specifically inhibits the fast phase and enhances the medium phase. This effect is explained by assuming that the fast phase results from electron transfer from the water splitting system Z to the oxidized primary donor Y.3-(3,4-Dichlorophenyl)-1,1-dimethylurea (DCMU), in the presence of NH2OH elicits another fast phase. It is believed that DCMU affords a parasitic stabilization of C?+ by forming a complex with Q?. 相似文献
17.
Fully assigned 13C-NMR spectra confirm the C40 (16,16 -biphytanyl) structures of the alkyl chains in the ether lipids of extreme thermoacidophile bacteria of the Caldariella group. The incorporations of 13C- and 14C- labelled acetate and mevalonate provide further structural confirmation and define their biosynthetic origin. 相似文献
18.
The binding to isolated hepatocyte plasma membranes of radioactively labelled inhibitors of microfilamentous and microtubular protein function ([3H]cytochalasin B and [3H]colchicine, respectively) was studied as one means of assessing the degree of association of these proteins with cell surface membranes. [3H]Cytochalasin B which behaved identically to the unlabelled compound with respect to binding to these membranes was prepared by reduction of cytochalasin A with NaB3H4. The binding was rapid, readily reversible, proportional to the amount of membrane and relatively insentive to changes of pH or ionic strength. At 10?6 M [3H]cytochalasin B, glucose or p-chloromercuribenzoate, an inhibitor of glucose transport inhibited binding by about 20%; treatment of membranes with 0.6 M KI which depolymerizes F actin to G actin caused about 60% inhibition of binding. These two types of inhibition were additive indicating two separate classes of binding sites, one associated with sugar transport and one with microfilaments. Filamentous structures with the diameter of microfilaments (50 Å) were seen in electron micrographs of thin sections of the membranes. At concentrations greater than 10?5 M [3H]cytochalasin B, binding was proportional to drug concentration, characteristic of non-specific adsorption or partitioning. Intracellular membranes of the hepatocyte also bound [3H]cytochalasin B, those of the smooth endoplasmic reticulum to a greater extent than plasma membranes.[3H]Colchicine bound to plasma membranes in proportion to the amount of membrane and at a rate compatible with binding to tubulin. However, other properties of the binding including effects of temperature, drug concentration and antisera against tubulin were different from those of binding to tubulin. Hence, no evidence was obtained for association of microtubular elements with these membranes. Despite this there appeared to be an interdependence between microtubule and microfilament inhibitors: vinblastine sulfate stimulated [3H]cytochalasin B binding and cytochalasin B stimulated 3H colchicine binding. [3H]Colchicine also bound to intracellular membranes, especially smooth microsomes. 相似文献
19.
Cadmium is one of the most toxic heavy metals and is known to accumulate in freshwater food chains. The underlying mechanism
for its genotoxicity has not been investigated for any freshwater fish. It has, however, been suggested that cadmium-induced
carcinogenesis might involve either direct or indirect interaction of Cd2+ with DNA. The interaction between Cd2+ and DNA from the kidney of the silver crucian carp (Carassius auratus gibelio) in vitro and in vivo is investigated by spectrophotometric methods and agarose gel electrophoresis methods. Cd2+ could insert into DNA basepairs, bind to nucleic acid, and result in notable hypochromicities. The analysis of agarose gel
electrophoresis, proves that Cd2+ at different concentrations does not cause DNA cleavage in vitro; however, kidneys display the classical laddering degradation
of DNA in vivo, which is the result of the promotion of deoxyribonuclease activity or inhibition of superoxide dismutase and
catalyse activity and the accumulation of reactive oxygen species caused by Cd2+ ions in vivo. 相似文献
20.
Food searching behavior of the Buenos Aires tetra Hyphessobrycon anisitsi has been investigated before and after experimentally induced anosmia combined with visual deprivation. The threshold concentration of a water extract of familiar food (chironomid larvae) for fish with intact olfaction was 10–6 g/L. Induced anosmia led to complete loss of the search reaction to food odor. The chemosensory behavioral response to the water extract of food used at high concentrations (10-1-10-2 g/L) was not restored in fish after 1.5, 5, or 13.5 months of anosmia. The obtained results show that the external sense of taste is absent or extremely poorly developed in the Buenos Aires tetra. 相似文献