Metal Accumulation and Binding Protein Induction in <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis>, <Emphasis Type="Italic">Scapharca inaequivalvis</Emphasis>, and <Emphasis Type="Italic">Tapes philippinarum</Emphasis> from the Lagoon of Venice

Heavy metal pollution is known to be widespread in the sediments of the Lagoon of Venice. Therefore, physiological parameters influenced by this form of contamination were examined. The bivalve molluscs blue mussel (Mytilus galloprovincialis), ark clam (Scapharca inaequivalvis), and Japanese littleneck (Tapes philippinarum) were sampled in two sites (Marghera, Chioggia) every 3 months for 1 year. The digestive gland and gills of each bivalve were analyzed. The concentrations of essential and nonessential metals (including chromium, manganese, iron, cobalt, nickel, copper, zinc, and cadmium) were determined. Because glutathione and metallothioneins (MTs) are involved in metal homeostasis and detoxification, their concentrations were evaluated in relation to metal concentrations. Results show that (1) all three studied species accumulate metals to a considerable extent, with some species-specific differences between the digestive gland and gills; (2) gills are a good tissue to evaluate pollution by examining the MT content. In particular, the correlation between Zn and MT levels in the gills indicates that M. galloprovincialis and S. inaequivalvis are sentinel organisms and can be used specifically for Zn pollution; (3) T. philippinarum accumulates Cu in the digestive gland more readily than the other two bivalves and therefore has the highest MT. Received: 20 December 2001/Accepted: 11 November 2002     

Effects of Hypoxia and Sedimentary Naphthalene on the Activity of <Emphasis Type="Italic">N</Emphasis>-acetyl-<Emphasis Type="Italic">β</Emphasis>-Glucosaminidase in the Epidermis of the Brown Shrimp, <Emphasis Type="Italic">Penaeus aztecus</Emphasis>

The brown shrimp, Penaeus aztecus, is subject to dual stresses of environmental hypoxia and contamination of polycyclic aromatic hydrocarbons (PAHs) in the northern Gulf of Mexico. The effects of hypoxia and sedimentary naphthalene, administered alone and in combination, on epidermal activity of N-acetyl-β-glucosaminidase (NAG), a biomarker for molt-interfering effects in P. aztecus, were investigated. It was found that hypoxia and sedimentary naphthalene, when given simultaneously, significantly inhibited epidermal NAG activity, suggesting that these two environmental stressors together can have adverse effects on molting of the brown shrimp. The results of this study also show that sedimentary naphthalene potentiates hypoxia effects on epidermal NAG activity.     

<Emphasis Type="Italic">GSTM1</Emphasis> and <Emphasis Type="Italic">APE1</Emphasis> genotypes affect arsenic-induced oxidative stress: a repeated measures study

Background  

Chronic arsenic exposure is associated with an increased risk of skin, bladder and lung cancers. Generation of oxidative stress may contribute to arsenic carcinogenesis.     

Soil <Emphasis Type="Italic">Pseudomonas</Emphasis> Community Structure and Its Antagonism Towards <Emphasis Type="Italic">Rhizoctonia solani</Emphasis> Under the Stress of Acetochlor

In a microcosm experiment, the amplified ribosomal DNA restriction analysis was adopted to investigate the Pseudomonas community structure in soils applied with different concentrations (0, 50, 150, and 250 mg/kg) of acetochlor, and an in vitro assay was made to examine the antagonistic activity of isolated Pseudomonas strains acting on soil-borne pathogen Rhizoctonia solani. The results showed that acetochlor application changed the community structure of Pseudomonas in aquic brown soil. The diversity of Pseudomonas and the amount of isolated Pseudomonas strains with antagonistic activity decreased with an increasing acetochlor concentration, and the toxic effect of acetochlor reached to a steady level at 150–250 mg/kg.     

Laboratory based surveillance of travel-related <Emphasis Type="Italic">Shigella sonnei</Emphasis> and <Emphasis Type="Italic">Shigella flexneri</Emphasis> in Alberta from 2002 to 2007

Between 2002 and 2007, travel related cases of Shigella sonnei and S. flexneri in Alberta, Canada were acquired from Central America, the Indian subcontinent and North America. Of this group, resistance to ciprofloxacin and nalidixic acid was identified in isolates from patients who had travelled to the Indian subcontinent. This study provides a Canadian perspective to a growing body of literature linking ciprofloxacin and nalidixic acid resistance to travel to the Indian subcontinent.     

Effects of Temperature on the Sensitivity of <Emphasis Type="Italic">Gammarus</Emphasis><Emphasis Type="Italic">aequicauda</Emphasis> (Martynov, 1931) to Cadmium

Gammarus aequicauda, collected at different times of the year was used to assess the mortality rates and the sensitivity to cadmium (96 h LC50), at different laboratory temperatures (10, 15, 20, 25°C). The survival in 10 days sediment control test, was high at all tested temperatures, ranging from 4 ± 1% at 10°C (winter collection) to 13.3 ± 2.1% at 25°C (spring collection). The 96 h-LC50 values recorded, ranged from 1.50 mgCd/L in winter at 10°C to 0.10 mgCd/L in spring and summer at 25°C. The results showed that temperature and season of collection influenced mortality rates and G. aequicauda sensitivity to cadmium.     

Comparison of Sensitivity of Grasses (<Emphasis Type="Italic">Lolium perenne</Emphasis> L. and <Emphasis Type="Italic">Festuca rubra</Emphasis> L.) and Lettuce (<Emphasis Type="Italic">Lactuca sativa</Emphasis> L.) Exposed to Water Contaminated with Microcystins

The effects of aqueous extracts from Microcysts aeruginosa strains (both microcystin-producers and non-microcystin producers) on germination and root growth were investigated for three economically important plant species: Festuca rubra L., Lolium perenne L., and Lactuca sativa L. There was a clear inhibition of root growth for L. sativa exposed to strains containing microcystins (5.9–56.4 μg L⁻¹). The strain that produced the most pronounced effects contained the lowest concentration of microcystin suggesting that other cellular compounds may also affect growth.     

A modified version of Moran's <Emphasis Type="Italic">I</Emphasis>

Background  

Investigation of global clustering patterns across regions is very important in spatial data analysis. Moran's I is a widely used spatial statistic for detecting global spatial patterns such as an east-west trend or an unusually large cluster. Here, we intend to improve Moran's I for evaluating global clustering patterns by including the weight function in the variance, introducing a population density (PD) weight function in the statistics, and conducting Monte Carlo simulation for testing. We compare our modified Moran's I with Oden's I * _pop for simulated data with homogeneous populations. The proposed method is applied to a census tract data set.     

Toxicokinetics of Organic Contaminants in <Emphasis Type="Italic">Hyalella azteca</Emphasis>

Uptake, biotransformation, and elimination rates were determined for pentachlorophenol (PCP), methyl parathion (MP), fluoranthene (FU), and 2,2′,4,4′,5,5′-hexachlorobiphenyl (HCBP) using juvenile Hyalella azteca under water-only exposures. A two-compartment model that included biotransformation described the kinetics for each chemical. The uptake clearance coefficients (k_u) were 25.7 ± 2.9, 11.5 ± 1.1, 184.4 ± 9.3, and 251.7 ± 9.0 (ml g⁻¹ h⁻¹) for PCP, MP, FU, and HCBP, respectively. The elimination rate constant of the parent compound (k_ep) for MP was almost an order of magnitude faster (0.403 ± 0.070 h⁻¹) than for PCP and FU (0.061 ± 0.034 and 0.040 ± 0.008 h⁻¹). The elimination rate constants for FU and PCP metabolites (k_em) were similar to the parent compound elimination 0.040 ± 0.005 h⁻¹ and 0.076 ± 0.012 h⁻¹, respectively. For MP, the metabolites were excreted much more slowly than the parent compound (0.021 ± 0.001 h⁻¹). For PCP, FU, and MP whose metabolites were measured, the biological half-life (t_1/2p) of the parent compound was shorter than the half-life for metabolites (t_1/2m) because the rate is driven both by elimination and biotransformation processes. Thus, H. azteca is capable of metabolizing compounds with varying chemical structures and modes of toxic action, which may complicate interpretation of toxicity and bioaccumulation results. This finding improves our understanding of H. azteca as a test organism, because most biomonitoring activities do not account for biotransformation and some metabolites can contribute significantly to the noted toxicity. Received: 13 June 2002/Accepted: 21 October 2002     

<Emphasis Type="Italic">Passing It On</Emphasis> During a <Emphasis Type="Italic">Day In The Life</Emphasis> of Resilient Adolescents in Diverse Communities Around the Globe

This social-ecological inquiry explores youth resiliency in diverse communities using innovative qualitative visual methodologies. It engages adolescents in a process of sharing their daily experiences and reflecting on the resources they bring to bear to thrive in the face of geographic and social relocations. The four youth participants were identified by local community advisors as especially resilient teenagers despite experiencing transitions that could provoke risks to normative development. The youths were interviewed and videotaped during a weekend day in [their] lives. They also engaged in deliberations on that day; took part in a photo elicitation that reflected on significant people, places, and objects in their environments; and responded to a resilience questionnaire. These visual data and the youths’ deliberations were analyzed for themes of positive identity and personal control observed within and across communities by their passing on the nurturant interchanges they themselves had experienced during that day.     

<Emphasis Type="Italic">Aedes albopictus</Emphasis> and the reemergence of Dengue

Dengue is a vector-borne disease that is estimated to affect millions of individuals each year in tropical and subtropical areas, and it is reemerging in areas that have been disease-free for relatively long periods of time. In this issue of the journal, Peng et al. report on a Dengue outbreak in a city in southern China that had been disease-free for more than two decades. The infection, which was due to serotype 1, was introduced by a traveler from South-east Asia and transmitted by Aedes albopictus, the Asian tiger mosquito. Compared to Aedes aegypti, which is the most important vector of Dengue, Ae albopictus is a less competent vector of arboviruses, and the epidemics it causes are milder. However, Ae albopictus is becoming an increasingly important vector because of its rapidly changing global distribution. In particular, the worldwide trade in second hand tires, which often contain water and are an ideal place for eggs and larvae, has been a key factor in the large-scale conquest of Ae albopictus, which easily adapts to new environments, even in a temperate climate. This expansion is creating new opportunities for viruses to circulate in new areas, becoming a common cause of epidemics in Ae aegypti-free countries, from Hawaii to Mauritius. The outbreak in China, like similar events, was mild and short-lived. Because epidemics due to Ae albopictus are milder, the replacement of Ae aegypti with the tiger mosquito could even result in public-health benefits. However, there is no solid evidence of this, and the milder course of the outbreak could be in part explained by the relatively short duration of the hot season in some affected areas. Since it is almost impossible to prevent Ae albopictus from being introduced in a country, mosquito-control measures at local level remain the most effective means of controlling arbovirus outbreaks.     

Investigation of the Multixenobiotic Resistance Mechanism in the Freshwater Fishes Western Mosquitofish, <Emphasis Type="Italic">Gambusia affinis</Emphasis>, and Bluegill Sunfish, <Emphasis Type="Italic">Lepomis macrochirus</Emphasis>

The purpose of the study was to evaluate multixenobiotic resistance mechanism expression as a biomarker for contaminant exposure in freshwater fishes. Exposure to a known mammalian inhibitor (verapamil, 10 μM) and inducer (rhodamine 123, 3 μM) on the transport protein P-glycoprotein (Pgp) was investigated in the liver of the western mosquitofish and bluegill sunfish. No differences in the activity or expression of Pgp were measured in either species using a fluorometric accumulation assay and western blot analyses. The preliminary results from this study indicate that this detoxification mechanism may not be a sensitive indicator of contaminant exposure in certain teleost species.