Yolk Synthesis in the Marine Shrimp, Penaeus vannamei

Eyestalk neuroendocrine factors control specific yolk proteinsynthesis in the ovaries of the shrimp, Penaeus vannamei. Abioassay was developed to measure specific yolk protein synthesisin vitro. The eyestalk neuroendocrine complex may also producea peptide capable of stimulation of yolk synthesis.     

Phytotoxic Effects of Cd, Zn, Pb, Cu and Fe on Sinapis Alba L. Seedlings and their Accumulation in Roots and Shoots

The inhibitory effects of Cd, Cu, Zn, Pb, and Fe on root elongation, contents of photosynthetic pigments, and metal accumulation in the roots and shoots of Sinapis alba were assessed. On the basis of growth inhibition metals can be arranged in a order Cu > Cd > Fe = Zn > Pb. All the metals, except Fe, were accumulated in significantly higher amount in the roots than in the shoots. Cd, Zn, Cu and Pb reduced chlorophyll a, and especially chlorophyll b content, and Zn and Pb reduced the carotenoid content, but less than that of chlorophyll a+b. The plants contained the highest concentration of Cd, and the lowest concentration of Zn.     

Epidermal uptake of Pb,Cd, and Zn in tubificid worms

Summary The epidermal uptake of Pb, Cd, and the essential element Zn by tubificid worms was investigated. The animals were starved and contaminated via the water column at 4°C and 25°C. Atomic absorption spectroscopy (AAS), energy-dispersive X-ray microanalysis (EDX), laser induced mass analysis (LAMMA), electron microscopy, and the sulfide-silver method at the electron microscopical level were used. The sulfidesilver method revealed many reaction products indicating heavy metals in membrane-limited lysosomal structures in epidermal cells of contaminated Limnodrilus udekemianus. In these lysosomes, which were particularly abundant in the epidermis of the hind end, Pb, Cd, and Zn were detected by LAMMA and EDX analysis. Beside this distinct occurrence of the three elements a uniform pattern of reaction products was found in epidermal cells after contamination with Cd and Zn, but not after treatment with Pb. As shown by atomic absorption spectroscopy, Cd was the most enriched element at 25°C, followed by Pb and Zn. Simultaneous application of Zn reduced the uptake of Cd, whereas the uptake of Pb was increased. At 4° C uptake of Pb and Cd was slower than at 25° C, while Zn uptake was blocked completely. This shows that heavy metal uptake can be strongly dependent on environmental conditions, which has to be taken into account if animals are used as monitor organisms for heavy metal pollution in the environment.     

CEHIXM Extraction of Pb,Cd, Zn,and Mn from High Permeable Soils

A new method CEHIXM for extracting hea vy metals from high permeable soils under coupled electric-hydraulic gradient was investigated. Spent foundry sand, containing high levels of Pb, Cd, Zn, and Mn, was used as the contaminated source. A suitable ion-exchange resin was used for trapping and recovering the metals from the aqueous medium. Control experiments were conducted using hydraulic gradient alone to assess the leachability of the contaminants. The experiments were repeated with 50?V across the soil sample and without hydraulic gradient to evaluate ion migration under electric gradient. A number of CEHIXM experiments involving both hydraulic and electric gradients were conducted at a constant DC voltage of 50?V and a constant flow velocity of 0.0178?cm/ sec. With hydraulic gradient only, 3 to 8% metals were extracted, whereas with electric gradient only the metal removal rate was 0 to 0.7%. When the electric and hydraulic gradients were coupled, as much as 93% of Pb, 97% of Cd, 98% of Zn, and 94% of Mn were extracted, after 100?h of the processing.     

重金属Cd、Zn、Cu、Pb对土壤微生物和酶活性的影响

采用室内培养实验(25℃),研究了不同培养时间下重金属Cd、Zn、Cu、Pb(浓度分别为50,800,400,800mg.kg-1)污染对土壤微生物和酶活性的影响。结果表明,土壤蔗糖酶、过氧化氢酶和脱氢酶活性随着培养时间的增加而显著下降,在培养20d的时候达到最小值,然后酶活性缓慢升高。Cu对脲酶活性以及Cd对酸性磷酸酶和脲酶活性的抑制作用随时间增加而增加。土壤微生物生物量碳、细菌、真菌和放线菌数量随培养时间的增加均表现出先降低后升高的变化趋势。Cd和Cu对微生物生物量氮的抑制作用则随着培养时间的增加而增强,在培养30d时微生物生物量氮到达最低值,分别较培养10天减少了12.6%和16.5%。     

Accumulation of Cu, Zn, Pb, and Cd in edible parts of four commonly grown crops in two contaminated soils

Soil heavy metal pollution resulting from human activities is causing major concern due to its potential risk. In this study, four crop species with different cultivars were planted in 2 levels (heavily and slightly) of heavy metal contaminated soils, and the accumulation of Cu, Zn, Pb, and Cd in the edible parts of the crops were investigated. Metal concentrations in sesame seeds grown in both soils exceeded both the Chinese Food Hygiene Standard (CFHS) and Codex Alimentarius Commission Standard (CACS), while the metal concentrations in all pepper cultivars in the slightly contaminated soil were below the CFHS and CACS. Other crops were generally in between in both soils. Among the tested crops, the order of soil-plant transfer factor (TF) was: sesame > green soybean > cowpea > pepper. Additionally, old fruit of cowpea contained larger amounts of metals than young fruit. It suggests that sesame should not be planted in the metal contaminated area, while pepper cultivar "Chaobianjiao No.1" may be an alternative to be grown in the slightly contaminated soil. There were differences in individual human susceptibilities to metals. Therefore, a comprehensive risk assessment should consider the frequency, amount and species consumed by human besides metal concentrations in crops.     

东南景天对锌、镉复合污染的反应及其对锌、镉的吸收和积累特性

东南景天(Sedum alfredii Hance)已被鉴定为一种中国原生的新的锌超积累植物。 本文主要研究了锌(Zn)、镉(Cd)复合处理水平对东南景天的生长及其对锌、镉的吸收积累特性的影响。 结果表明,在Zn/Cd复合水平为500/100 祄ol/L时,植物生长最佳。Zn/Cd在东南景天叶片、茎部和根系中含量随着Zn/Cd处理水平的提高而增高。在Zn/Cd 复合水平为50/400 祄ol/L时茎叶中Cd含量达最高,其中叶片Cd含量达12.1 g/kg;在Zn/Cd 复合水平为1 000/50 祄ol/L时茎叶中Zn含量达最高, 其中茎中Zn含量达 23.2 g/kg。 植株各部位Cd含量的分布为:叶片>茎>>根系,而Zn在体内的分布为: 茎>叶片>>根系。 Zn、Cd在地上部和根部的积累量也随着处理水平的提高而增加,分别在Zn/Cd复合水平为250/400和500/100 祄ol/L下达高峰值。 东南景天地上部积累最高Zn和Cd的量分别达11和5 g/plant, 其比根系的积累量分别大10和25余倍。 Zn、Cd对东南景天的生长、吸收积累的相互作用依赖于Zn/Cd复合水平和植物部位。 在适宜Zn/Cd 处理水平范围内,Zn和Cd的吸收和积累具有相互促进作用。 高Zn或高Cd处理均抑制了植物对Zn和Cd的吸收和积累。 本研究结果表明,东南景天不仅具有忍耐高Zn/Cd复合污染,而且具有超量积累Zn和Cd的特异能力。 它为进一步研究植物Zn、Cd     

竹醋液与茶多酚对南美白对虾的复合保鲜研究

本文研究了竹醋液、茶多酚以及二者复配液对常见食源性致病菌大肠杆菌、金黄色葡萄球菌、铜绿假单胞菌及副溶血性弧菌的抑制效果。考察了竹醋液及茶多酚对上述四种供试菌的最低抑菌浓度,进而用于南美白对虾的保鲜。结果表明:竹醋液与茶多酚复配液具有协同抑菌作用。竹醋液、茶多酚及二者复配液对南美白对虾均有较好的保鲜效果,其中,复配液保鲜效果最佳,将南美白对虾货架期由原来的4 d延长到了7 d。     

东南景天对锌、镉复合污染的反应及其对锌、镉的吸收和积累特性

Sedum alfredii Hance has been identified as a new Zn-hyperaccumulator native to China. In this study, responses and metal accumulation of S. alfredii were examined under Zn/Cd complex polluted conditions. The results showed that optimal growth of S. alfredii in terms of the maximum dry matter yield was observed at Zn/Cd complex level of 500/100 祄ol/L. Plant cadmium (Cd) or zinc (Zn) concentrations increased with increasing Cd or Zn supply. During the 20 d treatment, the highest Cd concentration in the leaves reached 12.1 g/kg at Zn /Cd level of 50/400 祄ol/L and that of Zn in the stems was 23.2 g/kg at Zn/Cd level of 1 000/50 祄ol/L. The distribution of Cd in different plant parts decreased in the order: leaf ＞ stem≥ root, whereas that of Zn was: stem ＞ leaf ≥ root. The accumulation of Cd and Zn in the shoots and roots of S. afredii increased with the increasing of Zn/Cd supply levels, peaked at Zn/Cd levels of 250/400 and 500/100 祄ol/L, respectively. The highest Cd and Zn uptake by the shoots was approximately 5 and 11 mg/plant, and was over 20 and 10 times higher than those in the roots, respectively. Zn supply at levels ≤ 500 祄ol/L increased plant Cd concentrations, whereas high Zn supply decreased root Cd but did not affect leaf Cd concentrations in S. alfredii. Low Cd supply increased Zn concentration in the leaves, but Cd supply higher than 50 祄ol/L considerably reduced root Zn concentrations, especially at low Zn level. These results indicate that S. alfredii can tolerate high Zn/Cd complex levels and has an extraordinary ability to hyperaccumulate not only Zn but also Cd. It could provide a new valuable plant material for understanding the mechanisms responsible for co-hyperaccumulation of Zn and Cd as well as for phytoremediation of the Cd/Zn complex polluted soils.     

Serum levels of Cd, Pb, Cu and Zn in cigarette smokers

In order to show the accumulation of Cd, Pb, Cu and Zn in smokers, levels of these metals in serum were determined in 108 subjects: 32 non-smokers, 37 average cigarette smokers and 39 heavy cigarette smokers. The analysis was carried out by potentiometric stripping analysis (PSA) with the Tecator "Striptec System". Backward oxidation time of the amalgamated metals, by means of electrolysis, in a thin "film" of mercury in an electrode, gives their concentration measure. Our data showed an increase in average values of Cd and Pb in the serum of heavy smokers compared with average and non-smokers. Instead, as regards Cu and Zn, no differences were found in the two groups of smokers compared with the non-smokers used as controls. Results obtained of the Cd and Pb levels in serum are compatible with the presence of these metals in cigarette tobacco and inhaling them could contribute to disease connected with their accumulation in the human organism. For these subjects the increase in Cd values is of particular importance as it could predispose pulmonary emphysema.     

Phytoremediation of Cd,Ni, Pb and Zn by Salvinia minima

Most metals disperse easily in environments and can be bioconcentrated in tissues of many organisms causing risks to the health and stability of aquatic ecosystems even at low concentrations. The use of plants to phytoremediation has been evaluated to mitigate the environmental contamination by metals since they have large capacity to adsorb or accumulate these elements. In this study we evaluate Salvinia minima growth and its ability to accumulate metals. The plants were cultivated for about 60 days in different concentrations of Cd, Ni, Pb and Zn (tested alone) in controlled environmental conditions and availability of nutrients. The results indicated that S. minima was able to grow in low concentrations of selected metals (0.03 mg L^?1 Cd, 0.40 mg L^?1 Ni, 1.00 mg L^?1 Pb and 1.00 mg L^?1 Zn) and still able to adsorb or accumulate metals in their tissues when cultivated in higher concentrations of selected metals without necessarily grow. The maximum values of removal metal rates (mg m² day^?1) for each metal (Cd = 0.0045, Ni = 0.0595, Pb = 0.1423 e Zn = 0.4046) are listed. We concluded that S. minima may be used as an additional tool for metals removal from effluent.     

Effects of Total Soft Tissue and Shell Thickness on the Accumulation of Heavy Metals (Cd,Cu, Pb,and Zn) in the Green-Lipped Mussel Perna viridis

The effects of the total soft tissue dry weight and shell thickness and on the accumulation of Cd, Cu, Pb, and Zn were determined in the green-lipped mussel Perna viridis. In agreement with Boyden's formula (1977), our results showed that the plotting of metal concentrations against the total soft tissue dry weight and shell thickness of the mussel on a double logarithmic basis gave negative coefficients especially for Cd, Pb, and Zn. Therefore, the smaller mussels (lower total soft tissue dry weight) had higher concentrations of Cd, Pb, and Zn than the larger ones. Since shell thickness could be considered to estimate of the age of the mussel, it was also found that the younger mussels accumulated more Cd, Pb, and Zn than the older ones. This indicated that P. viridis has a different metabolic strategy for each of the metals studied which may be related to age. However, the accumulation of Cu was hardly affected by the sizes and ages of the mussel. This indicated that the accumulation pathways of Cu and the processes affecting the bioavailability of Cu to the mussel are different from those for Cd, Pb, and Zn.     

Litter accumulation in woodlands contaminated by Pb,Zn, Cd and Cu

Summary Close to a primary lead-zinc-cadmium smelter the standing crop of litter in woodlands was found to be elevated relative to more distant sites. The total litter accumulation is similar to that from contaminated sites reported by other authors but in this case the concentrations of heavy metals are considerably lower than those reported for other sites. Evidence is provided to support the hypothesis that within the woodlands studied, litter accumulation is not closely pH dependent, but is clearly related to both cadmium and zinc concentrations in litter. Litter accumulation occurs in certain particle size ranges and fractionation shows that the weight of accumulated litter in these size ranges is highly correlated to cadmium concentrations. These results are discussed in relation to the reported possible long term effects of metal contamination on decomposition processes and the possibility of adaptation to these adverse effects.     

Metal (Fe, Zn, Cu, Pb and Cd) concentration patterns in components of a macrophyte-based coastal lagoon ecosystem

Information on the metal biological fate in macrophyte-based coastal lagoons is provided; this information can contribute to the assessment of the environmental effects of metal pollution and to the development of predictive models for rational management of coastal lagoons. Iron, Zn, Cu, Pb and Cd concentrations in the dominant invertebrate and fish species of Monolimni Lagoon, Mediterranean Sea, as well as in potential major sources for metal accumulation in these animals (water, sediments, angiosperms, seaweeds), were measured. Principal Component Analysis (PCA) was conducted using metal concentrations in invertebrates and fishes. All five metal concentrations loaded significantly on the first PCA axis; however, Zn and Cu loadings were less significant than Cd and even less than Fe and Pb ones. The samples of deposit-feeding invertebrates were separated from those of the rest of the organisms (browsing, herbivorous and carnivorous invertebrates, carnivorous gobies and muscle tissues of detritivorous mullets) along the first PCA axis. Deposit-feeding invertebrates displayed the highest Fe and Pb contents, and in general, the highest or comparatively high Cd, Zn and Cu ones. Carnivorous gobies showed comparatively high Zn contents and carnivorous shrimps the highest Cu ones, while muscle tissues of detritivorous mullets had low metal loads. In addition, there was no essential increase in metal concentrations corresponding to the increasing trophic level (autotrophs, to herbivores, to carnivores). Our findings suggest that (a) the variability in Fe, Pb and Cd contents in invertebrates and gobies depends at least to some extent on interspecific differences in feeding habits—deposit feeders accumulated the highest metal amounts probably due to high rates of uptake from sediments, (b) the variability in Zn and Cu concentrations in these organisms depends also on other interspecific differences apart from those in feeding habits, (c) metal accumulation in mullet muscle tissues does not depend markedly on feeding habits and (d) the trophic transfer of macrophyte-bound metals to the coastal lagoon food web is of relatively minor importance.     

Accumulation properties of As,Cd, Cu,Pb and Zn by four wetland plant species growing on submerged mine tailings

Plants may reduce element leakage from submerged mine tailings by phytostabilisation. However, high shoot concentrations of elements might disperse them and could be harmful to grazing animals. The aim of this investigation was to find out which of the three properties; low-accumulation, root accumulation or shoot accumulation of elements, occur in four of the most common wetland species growing on an old submerged mine tailings and if their properties can be determined by a hydroponic experiment. Above- and below-ground parts of Salix (mixed tissue from S. phylicifolia and S. borealis), Carex rostrata, Eriophorum angustifolium, and Phragmites australis were sampled and analysed for Cd, Cu, Zn, Pb and As. Differences in uptake and translocation properties of the same plant species were observed between field-grown plants and plants grown in hydroponics. These differences were probably due to processes in the soil–root interface. Thus, hydroponic screening studies should not be used to find suitable species for vegetation of wet-covered mine tailings. Most species were found to have restricted translocation of elements to the shoot, i.e. they were root accumulators, and only the shoot concentrations of Salix for Cd and Zn and E. angustifolium for Pb might be toxic to grazing animals. Thus, plant establishment on submerged tailings can be a safe method to stabilise the metals.     

蕹菜典型品种中Cd、Pb、Cr、Ni 等重金属含量及其相关性

目的:蕹菜(Ipomoea aquatica Forsk.)Cd(镉)积累典型品种对Cd、Pb(铅)、C(r铬)、N(i镍)等多种重金属的吸收积累及相互关系。方法:采用盆栽试验,分析4个蕹菜Cd积累典型品种在6种土壤上的两茬茎叶及根Cd、Pb、Cr、Ni含量及相关性。结果:①品种和土壤对供试蕹菜典型品种Cd含量的效应均达显著水平(P<0.05),对Pb、Cr和Ni含量的效应因重金属、收获时期及部位而不同,二者对Cd、Pb含量具一定的交互效应。②两茬茎叶Cd含量平均值均为T308>GDB>QLB>QLQ,根Cd平均含量高于茎叶Cd平均含量;除Cr外,根Pb和Ni平均含量均高于茎叶。③Cd、Pb、Cr、Ni含量呈现复杂的相关关系。茎叶Cd含量与Pb含量正相关,且第一茬相关性极显著(P<0.01);Pb含量与Ni含量相关关系明显,第一茬茎叶、根Pb含量与Ni含量的正相关达到显著(P<0.05)或极显著水平(P<0.01),但第二茬茎叶Pb含量与Ni含量却显著负相关(P<0.05);Pb含量与Cr含量的相关性仅第一茬茎叶显著(P<0.05);Cr含量与Ni含量的相关性仅第二茬茎叶达极显著水平(P<0.01)。结论:蕹菜典型品种对Cd、Pb、Cr、Ni的吸收积累存在协同和拮抗两种作用。     

石灰配施猪粪对Cd、Pb和Zn污染土壤中重金属形态和植物有效性的影响

通过盆栽试验,研究在镉、铅和锌污染土壤上,石灰和猪粪配施对土壤中不同形态镉、铅和锌含量及在蔬菜中累积的影响.结果表明:施入石灰(L)、石灰加低量猪粪(LP1)、石灰加高量猪粪(LP2)后,土壤中碳酸盐结合态Cd、Pb和Zn含量明显降低,土壤中铁、锰氧化物结合态和有机物结合态Cd、Pb和Zn含量明显增加;对大白菜吸收Pb、Cd和Zn均起到较好的抑制作用.单施石灰处理,石灰用量为5 g·kg-1土时,对大白菜吸收Pb、Cd和Zn的抑制效果最好;石灰配施猪粪处理,其中石灰5 g·kg-1土配施猪粪7.5 g·kg-1土以及石灰5 g·kg-1土配施猪粪15 g·kg-1土对大白菜吸收Pb、Cd和Zn的抑制效果最好.研究同时发现,低量猪粪配施石灰的效果强于高量猪粪配施石灰的效果.     

Yolk synthesis in the marine shrimp,Penaeus vannamei

• 1.1. In vitro yolk synthesis was measured in fragments of the ovary of developing shrimp, Penaeus vannamei.
• 2.2. Progesterone and estradiol stimulated yolk synthesis in vitro, while ecdysterone, testosterone and estrogen had no effect.
• 3.3. A peptide factor from the eyestalks of crayfish stimulated yolk synthesis in vitro. A peptide factor from shrimp eyestalks inhibited yolk synthesis in vitro.

     

Interspecific differences in Zn,Cd and Pb accumulation by freshwater algae and bryophytes

The relationships between the concentrations of zinc, cadmium and lead in aquatic plants and the concentrations of these metals in the ambient water have been compared for three algae (Lemanea fluviatilis, Cladophora glomerata, Stigeoclonium tenue), one liverwort (Scapania undulata) and three mosses (Amblystegium riparium, Fontinalis antipyretica, Rhynchostegium riparioides). The data to establish these relationships are all based on our own studies, some published already, some here for the first time. They come from a wide range of streams and rivers in Belgium, France, Germany, Ireland, Italy and the U.K. There were significant bivariate positive relationships between concentrations of Zn, Cd and Pb in water and plant for all species except Cd and Pb in Stigeoclonium tenue. When relationships were compared using datasets with total or filtrable metals in water, most differences were slight. However there were marked differences both between species and between metals. Comparison for the seven species of Zn in the plant when aqueous Zn is 0.01 mg l^–1, a concentration at which all seven were found, shows that the four bryophytes had the highest concentrations; however the two green algae had steeper slopes (representing change in concentration in plant in response to change in aqueous concentration). Lemanea fluviatilis had a slope closer to that of the bryophytes, but the concentration was about one order of magnitude lower. All seven species were found at a concentration of 0.01 mg l^–1 Pb, and at this concentration there were almost two orders of magnitude difference between the species which accumulated the most (Scapania undulata) and the one which accumulated the least (Cladophora glomerata). The steepest slope was however shown by C. glomerata.When multiple stepwise regression was applied, the aqueous metal under consideration was the first variable extracted in only nine of the 21 regressions. However one of the other heavy metals (aqueous or accumulated) was extracted first in all but one of the other regressions, presumably because the occurrences of Zn, Cd and Pb were strongly cross-correlated. The principal non-heavy metal factor extracted for Zn and Cd, but not Pb, was aqueous Ca. The relevance of these results to the use of aquatic plants for monitoring heavy metals is discussed.