CADMIUM, COPPER AND LEAD IN GASTROPODS OF THE LOWER NELSON RIVER SYSTEM, MANITOBA, CANADA

Cadmium, copper and lead were examined in whole snails fromthe Lower Nelson River system. Concentrations of the three metalswere significantly correlated with each other. Lead was accumulatedleast, while copper was present in the greatest concentrations.Significant interspecific differences were found for copper.Total body burdens increased with snail size and weight, butconcentrations per unit dry weight decreased with size and weightin some species. Metal concentrations in snails were not significantlycorrelated with metal content of the sediments. In Gyraulus,copper and lead concentrations were correlated with levels ofthese metals in the host macrophytes. Seasonal differences inmetal concentration appeared to be related to differences inage structure of the populations. (Received 5 September 1991; accepted 30 October 1991)     

Dry Weight Production and Partitioning inMedicago minimaandErodium cicutariumUnder Water Stress

Medicago minimaandErodium cicutariumare two naturalized annualspecies in extensive semi-arid, temperate rangelands of centralArgentina. A field study was conducted during 1989 and 1990to evaluate the effects of different levels of soil water availabilityon above- and below-ground dry weight production and partitioningin these species. Dry weight production byM. minimawas moresensitive to water stress than that byE. cicutarium. Althoughthe response was more marked inM. minima, both species allocateda larger proportion of total plant dry weight to fruits underwater stress than under irrigated conditions during early spring.Percentage allocation of total plant dry weight into reproductiveorgans in both species, and stems and peduncles inE. cicutarium,was correlated with total dry weight of these organs; this mightindicate a correlation between sink size and strength. Persistenceof both species in the local flora appears to be associatedwith their capacity to colonize open, degraded areas and growin association with native perennial grasses, as well as totolerate severe drought periods.Copyright 1998 Annals of BotanyCompany Medicago minima(L.) Grufb. var.minima,Erodium cicutarium(L.) L'Herit, water stress, dry matter production and partitioning.     

A snail's space sets a snail's pace: movement rates of lavigeria gastropods in lake tanganyika, East africa

Endemic Lavigeria gastropods are diverse and common in the benthosof Lake Tanganyika. We used in situ studies of marked individualsto quantify rates of daily movement by three species, and testthe effects of size, sex, reproductive status and parasitismon movement. Average net travel distance was 50 cm day^–1,which corresponds to about 20 times shell length. Male L. coronatamoved significantly farther than L. coronata females or L. grandis,and L. nassa of either sex. There were also significant differencesamong individuals within each group; however, these differenceswere not predicted by size, reproductive status or parasitism.We interpret greater movement of L. coronata males as a reflectionof mate searching; the ratio of males to non-brooding, non-parasitizedfemales was three times as high in L. coronata (21:1) as inthe other species (6:1). Our results indicate that these snailsare capable of moving considerable distances, and that the highlylocalized distribution of L. coronata populations is not simplya reflection of limited movement by individual snails. (Received 20 September 2006; accepted 1 March 2007)     

Heavy metal concentrations in,and human health risk assessment of,three commercially valuable fish species in the lower Niger River,Nigeria

The concentrations of Fe, Mn, Ni, Pb and V in water, sediment and the gill, liver and muscle tissues of Synodontis resupinatus, Heterotis niloticus and Clarias gariepinus, all commercially important fish species of the lower Niger River, were investigated in 2015. Water, sediment and fish samples were collected for six months and heavy metals were determined using an Atomic Absorption Spectrometer. Fe ranked highest in water and sediment, with concentrations of 2.74 mg l^?1 and 61.60 mg kg^?1, respectively. Metals followed the magnitude of Fe > Mn > Ni > V > Pb in the water and Fe > Mn > V > Ni > Pb in the sediments. Metal concentrations were higher in the tissues of S. resupinatus compared with H. niloticus and C. gariepinus. Fe was also highest in the gills, liver and muscle of the three fish species. Its highest concentration of 132.97 mg kg^?1 dry weight was recorded in the gills of S. resupinatus. Bioconcentration factors of metals ranged from 8.79 for Mn in H. niloticus muscle to 67.99 for Ni in S. resupinatus gills. The fish species studied pose no health risk for all metals studied, because the target hazard quotient was less than 1 and the estimated daily intakes of the metals were below the reference doses.     

Developmental Variation of the Neurotoxin, {beta}-N-Oxalyl-L-{alpha},{beta}-diamino propionic acid (ODAP), in Lathyrus sativus

Several species of the tribe Viceae (Leguminosae) produce non-proteinamino acids that are toxic to man and animals. The neurotoxinß-N-oxalyl-L-,ß-diamino propionic acid (ODAP)in cultivated Lathyrus sativus causes human neurolathyrism,a neurological disease resulting in the paralysis of lower limbs.Surveys have shown that there are large scale variations betweenspecies of Lathyrus and varieties of L. sativus for the amountof cellular ODAP. In the present investigation, thin-layer chromatographyand chemical analysis were used to study developmental variationin the amount of ODAP in tissues and organs of L. sativus. Theresults confirmed that the rate of synthesis and accumulationof ODAP varied during plant development. Increased rates ofsynthesis were confirmed in young seedlings and in the developingfruits of L. sativus.Copyright 1994, 1999 Academic Press Lathyrus sativus, neurotoxin, ODAP, plant development     

Influence of Complexation on the Uptake by Plants of Iron, Manganese, Copper and Zinc: I. EFFECT OF EDTA IN A MULTI-METAL AND COMPUTER SIMULATION STUDY

After growing barley (Hordeum vulgare L.) in nutrient solutionscontaining EDTA, uptake of the nutrient metals was determinedat three harvests and concentrations of the various chemicalspecies of each metal in the growth solutions was modelled bycomputer simulation. Complexation with EDTA had different effectson the uptake of the ions Fe³⁺, Mn²⁺, Cu²⁺, and Zn²⁺. At thehighest EDTA level (EDTA/Fe=2/l) the plants were chlorotic andgrowth was inhibited. This is attributed to a deficiency inZn rather than in Fe. The critical level of free Zn²⁺ requiredin nutrient solutions for healthy growth was found to be approximately10^–1010^–10 mol dm^–3, which is consistent withthat found by earlier workers for other plant species. Barleytolerated much lower levels of the free ions of copper and ironwithout exhibiting any obvious adverse effects. Key words: EDTA, micronutrients, trace metals, computer simulation, deficiencies, absorption, iron, manganese, copper, zinc     

THE SYSTEMATIC POSITION OF LAROCHEA FINLAY, 1927, AND INTRODUCTION OF A NEW GENUS AND TWO NEW SPECIES (GASTROPODA: SCISSURELLIDAE)

Species of the gastropod genus Larochea Finlay, 1927 are shownto be scissurellids without an anal shell slit or foramen. TheNew Zealand species, L. miranda Finlay, 1927 and L. secundaPowell, 1937, brood their young in the right subpallial cavityagainst a modified inner lip that is set well behind the aperturalplane. Larochea scitula n.sp. is based on shells from WanganellaBank, southern Norfolk Ridge. Larocheopsis n. gen. is introducedfor a minute species from off northern New Zealand that lacksa shell brood chamber. Larochea miranda and Larocheopsis amplexan.sp. are either gonochoristic with smaller males or consecutivehermaphrodites, while Larochea secunda and L. scitula are evidentlygonochoristic, having mature males and females of similar size. (Received 23 July 1992; accepted 10 December 1992)     

GENETIC AND CONCHOLOGICAL COMPARISON OF SNAILS (HELIX ASPERSA) DIFFERING IN SHELL DEPOSITION OF LEAD

Populations of snails inhabiting areas with different historiesof Pb contamination differed in their deposition of Pb in shellrelative to soft tissues. Genetic variation, measured usingisozymes, was not related to Pb history nor geographic distancebetween populations. Shell characteristics were significantlydifferent among sites; shell dry weight was strongly relatedto soil calcium levels. Shells of snails from areas with longhistories of Pb contamination were significantly more robust(greater shell width/shell height ratio) than snails from otherlocations. H. asprsa adaptation to Pb contamination may involvesignificant changes in shell characteristics but these do notcorrelate with genetic traits assessed with allozymes (Received 29 December 1994; accepted 15 October 1995)     

Cadmium and copper uptake and translocation in five willow (Salix L.) species

The efficacy for phytoremediation of five willow species was tested by experimental copper and cadmium uptake in a greenhouse hydroponic system. Five treatments included two concentrations (5 and 25 microM for each metal) and a control. Metal concentrations in solution as well as solution uptake were monitored. Metal resistance was assessed through effects on the dry weight of roots and shoots. The willow species tested were generally resistant of increased Cu and Cd content. Metal accumulation was found in all plant organs of all species. Growth and transpiration were not decreased by 5 microM of copper and 25 microM of cadmium in the solution for most species. 25 microM copper caused injury and reduced the dry weight for all species after 21 d. Salix nigra was highly resistant of both Cu and Cd and accumulated more metals than other species. Future field study should be conducted to confirm the findings and feasibility of the phytoremediation technology using those species.     

Phytoextraction capacity of trees growing on a metal contaminated soil

Phytoremediation is an innovative biological technique to reclaim land contaminated by heavy metals or organic pollutants. In the present work, we studied the ability of five woody species to extract heavy metal (copper, zinc or cadmium) from a polluted soil to their above-ground tissues. Metal content in leaves and twigs was determined. Salix and Betula transferred zinc and cadmium to leaves and twigs, but Alnus, Fraxinus and Sorbus excluded them from their above-ground tissues. None of the species considered transferred copper to the shoots.     

BIOCHEMICAL DETECTION AND IMMUNOHISTOCHEMICAL LOCALIZATION OF ENKEPHALIN-LIKE SUBSTANCES IN PERIPHERAL TISSUES OF THE SCALLOP PECTEN MAXIMUS (LINNAEUS)

This study focused on the biochemical detection of the methionine-enkephalin-,leucine-enkephalin-and methionine-enkephalin-arg-gly-leu-likepeptides in the stomach, digestive gland, male and female gonads,muscle, gill and mantle of the scallop Pecten maximus usingspecific radioimmunoassays. Enkephalin-like substances weremainly present in the stomach and in the digestive gland, whereleucine-enkephalin-and methionine-enkephalin-arg-gly-leu-likepeptides were the predominant of these substances. In the gonads,muscle, gill and mantle, the enkephalin-like contents were closeto the sensitivity threshold of the enkephalin antibodies. Theenkephalin-like contents measured in September, in the digestivecomplex, were significantly higher than in December, when thebivalves have undergone a period of starvation. Immunohistochemicalassays were performed on the stomach and the digestive glandto localize the enkephalin-like materials. In these organs,which are the main sites of the digestive process in Bivalyia,the enkephalin-like materials were mainly confined to the endocrine-likecells. These results suggest that in Pecten maximus, opioidsmay be involved in the digestive processes mainly through enkephalin-endocrine-likecells. (Received 29 December 1994; accepted 1 May 1995)     

SEXUAL DIMORPHISM OF NUCELLA LAPILLUS (GASTROPODA: MURICIDAE) IN NORTH WALES, UK

Multivariate statistical methods were employed to examine sexualdimorphism in size and shape of Nucella lapillus collected from 16sheltered sites along coasts of Anglesey and the Lleyn Peninsula, NorthWales, UK. Females were significantly larger than males in overallsize; among 12 relative measures of shell shape, two ratios (shellwidth/shell length and aperture length/shell length) were significantlydifferent between males and females, but these differences usuallydecreased with increasing age (shell length). The observed hypoallometricdimorphism could be a result of selection on increased femalefecundity, which may be positively correlated with shell sizein N. lapillus as in other gastropod species. (Received 22 November 1999; accepted 10 April 2000)     

The Translocation of Lead and Copper in Two Submerged Aquatic Angiosperm Species

The translocation of lead and copper was studied in two speciesof submerged aquatic angiosperm, Potamogeton crispus L. andPotamogeton pectinatus L. A perspex container incorporatinga potters' clay seal around the stems of intact plants was designedfor the chemical separation of the shoot and root environmentsduring 11–21 d treatment periods. Metal solutions wereadded to the root or shoot environments and concentrations weremonitored in waters and sediments. A technique was developedfor the direct quantitative analysis of metals in small (0.02–0.2mg) segments of water plant tissue, using the graphite rod attachmentto an atomic absorption spectrophotometer. Experimental resultsindicated minimal translocation of lead, but extensive acropetaltranslocation of copper to particular sites of accumulation.     

COMPARISONS OF LIFE-HISTORY TRAITS AND SEXUAL DIMORPHISM BETWEEN ASSIMINEA JAPONICA AND ANGUSTASSIMINEA CASTANEA (GASTROPODA: ASSIMINEIDAE)

Life histories of two sympatric assimineid gastropods, Assimineajaponica and Angustassiminea castanea, were investigated ata reed marsh in northern Japan. Size frequency distributionsrevealed that growth curves of females and males differed inboth species resulting in sexual dimorphisms in shell size.In A. japonica, the shell height of females was larger thanthat of males, whereas in A. castanea males attained a biggershell than females. Mating behaviour of A. japonica was observedmainly from February to June, while that of A. castanea wasobserved from May to August. The diameter of deposited eggsof A. japonica was 200 to 250 mm, whereas that of A. castaneawas 125 to 150 mm. The length of the veliger larva of A. japonicaat hatching was approximately 200 mm, whereas that of A. castaneawas approximately 125 mm. Longevity, age at sexual maturityand opportunities for reproduction during life time were estimatedin the field. For A. japonica, sexual maturity was establishedby the age of 17 months and longevity was about three years.Opportunities for reproduction of A. japonica occurred twiceduring a lifetime. For A. castanea, sexual maturity was establishedby the age of 10 months and longevity was almost five years.Opportunities for reproduction of A. castanea occurred fivetimes during a lifetime. The differences of life-history traitsand sexual dimorphism between species and possible explanationsof evolutionary factors are discussed. To whom correspondence should be addressed. (Received 21 January 1999; accepted 8 September 1999)     

Evaluation of copper and vanadium concentration in the soft tissue of Tylosurus crocodilus in Bahregan region,Persian Gulf

Abstract

The present study has been carried out to evaluate the concentration of copper (Cu) and vanadium (V) elements in the muscle, skin, and gill tissues of Tylosurus crocodilus (Belonidae), an edible fish, in the Bahregan region which is located in the northern part of the Persian Gulf. For this purpose, 18 fish samples in three different length groups (small, medium, and large) were randomly collected in Bahregan region. Tissues were separated and concentration of the heavy metals was determined by atomic absorption. The results showed that mean concentration of Cu and V were 0.2851 ± 0.10036 and 1.1368 ± 0.12405, 0.1117 ± 0.02322 and 2.5091 ± 1.14201 and 0.1803 ± 0.03204 and 3.3133 ± 1.05995 μg g^-1 dry weight, in skin, muscle and gill tissues, respectively. Also, the results revealed a significant positive correlation between the standard length and Cu concentration in the muscle and gill tissues (P ≤ 0.05), as well as between the standard length and V concentration in all the tissues (P ≤0.05). The results indicated that the concentration of V was higher than the World Health Organization (WHO) standard but the concentration of Cu was lower. It is therefore highly recommended that usage of this carnivore species in the studied area is limited because of the high accumulation of V in its muscle tissue.     

Effect of sex and size on the protein composition in the tissues of the freshwater crab,Paratelphusa (Barytelphusa) guerini Milne Edwards

Soluble (enzymic) and insoluble (structural) proteins were estimated quantitatively in different tissues of the crab as a function of sex and size. The different protein fractions in the tissues of females decreased with weight. But the proteins in the tissues of males increased gradually with size up to 30–40 g and decreased later. In both sexes, the relative increase and decrease varied in different tissues.The insoluble protein content of the muscle was always greater than the soluble content in both sexes. However, the two fractions in other tissues showed different trends depending upon the sex. The soluble content was always greater than the insoluble content in gill, heart and hepatopancreas of males. The hepatopancreas of females had a higher soluble content at all weights, as in males. But the insoluble proteins of the gill and soluble proteins of the heart were more in smaller animals (below 25–30 g) and less in larger animals (above 25–30 g).The soluble proteins dominated in the males. This relation was maintained in the muscle throughout the weight range studed (10 to 75 g), while in other tissues this relation was seen for the the greater part of this weight range. The insoluble proteins in the different tissues tended to be more in smaller females (up to 25–30 g) and larger males (above 25–30 g).The total protein content of the muscle was always larger in males. The proteins of the gill and heart were larger in males at higher sizes (above 20–25 g). Hepatopancreatic proteins were larger only at the intermediate-sized males (between 25 and 60 g).     

REPRODUCTIVE CYCLE AND FECUNDITY OF THE DATE MUSSEL LITHOPHAGA LITHOPHAGA (BIVALVIA: MYTILIDAE)

The reproductive cycle and fecundity of the date mussel Lithophagalithophaga, L. a well-known, ediblespecies has been examined.Sexes are separate and the mean number of eggs per each gonadis 1.894 x 10⁶ ± 1.044 x 10⁶ S.D. Reproduction firstoccurs at an age of 2⁺years and at a shell length greater than0.9 cm. Gonad activity is annual and is observed at all ages.The sex ratio for individuals up to 7 cm is 3:1 in favour ofthe males, whereas it becomes 1:1 for individuals greater than7 cm. The release of gametes by males and females occurs almostsimultaneously and begins immediately after a decline in thehighest water temperature ( 27°C), an increase in salinity(>31) and a decrease in the dissolved oxygen (6.5 ppm). Smallpercentages of mature individuals appear during the first wintermonths thus lengthening the reproductive period. This phenomenonis attributed to the temperature difference in deeper waters,the delay in gamete release by young individuals, tide, waveaction and changes in salinity. The fecundity of Lithophagalithophaga is high because its life-cycle is adversely affectedby environmental factors such as waves and tides. Fecundityincreases with shell length, more so with total wet weight andmainly with the age of the animals. Summer seems to be the suitableseason to exploit the date mussel of shell lengths > 5 cm. (Received 6 September 1993; accepted 10 March 1994)     

Trace Element Level in Different Tissues of <Emphasis Type="Italic">Rutilus frisii kutum</Emphasis> Collected from Tajan River,Iran

Tajan River is among the most significant rivers of the Caspian Sea water basin. In this study, the concentration of Cr, Cu, Fe, Mn, Ni, Pb, Cd, and Zn were determined in brain, heart, liver, gill, bile, and muscle of Rutilus frisii kutum which has great economic value in the Mazandaran state. Trace element levels in fish samples were analyzed by means of atomic absorption spectrometry. Nearly all non-essential metals levels (Ni, Pb, Cd) detected in tissues were higher than limits for fish proposed by FAO/WHO, EU, and TFC. Generally, non-essential metals (Ni, Pb) were so much higher in muscle than the essential metals (Cu, Zn, and Mn) except Fe, which was higher than other metals in nearly all parts, except in gills. Fe distribution pattern in tissues was in order of heart > brain > liver > muscle > bile > gill. Distribution patterns of metal concentrations in the muscle of fish as a main edible part followed the sequence: Fe > Pb > Ni > Cu > Mn > Zn > Cd.     

Predicting the Growth Interactions between Plants in Mixed Species Stands using a Simple Mechanistic Model

The Conductance model is a simple mechanistic model used topredict the growth of species in monoculture or mixtures fromparameter values derived from plants grown in isolation. Incontrast to many mechanistic models that require extensive parameterization,the Conductance model is able to capture the growth of a broadrange of species using a few simplified assumptions regardingplant growth and easily derived species-specific parameter values.We examine the assumptions within the Conductance model thattotal leaf area per plant is proportional to total plant weight,and that an isolated plant has a projected crown zone area thatis proportional to the 2/3 power of its weight. Power ratherthan linear relations were found between weight and leaf areafor Brassica oleracea, Daucus carota, Matricaria inodora, Solanumnigrum,Stellaria media , Trifolium repens and Veronica persica.For all seven species, the value of the power was less thanunity. All species also exhibited a power relation between crownzone area and weight, with the slope of this relation beingless than 2/3 for B. oleracea, D. carota and S. media. Althoughmorphology type accounted for some of the variation in the parametervalues relating to light interception, there were considerabledifferences between species within upright or prostrate foliagespecies groups. The Conductance model was used to predict yieldsof B. oleracea, S. nigrum and V. persica grown in both monocultureand binary weed-crop mixtures over a range of temporal and spatialscales. After calibrating the model to non-competing plants,the model was used to predict growth of the weed and crop speciesin contrasting densities and stand types. In some crop-weedcombinations, predicted crop and weed weights were within 17%of observed values, with no systematic deviations. In others,systematic and large deviations occurred.Copyright 2001 Annalsof Botany Company Brassica oleracea L., Daucus carota L., Matricaria inodora L., Solanum nigrum L.,Stellaria media L., Trifolium repens L., Veronica persica L., competition, growth, leaf area, crown zone area, light, shoot morphology, canopy architecture