Assessment of recent sediment influence in an urban polluted subantarctic coastal ecosystem. Beagle Channel (Southern Argentina).

In this study, baseline information about the environmental status of Ushuaia (UB) and Golondrina (GB) bays is presented. Surface and bottom seawater and freshwater discharged from land were evaluated. Multivariate analysis identified different water quality zones within the bays, two of them located next to the north and northwest coastlines of UB, where the majority of human activities are developed. Porosity, total organic matter, biochemical components, ammonium, and phytopigments were determined in sediment samples from each quality zone. Benthic fluxes of nutrients and dissolved oxygen were assessed in situ using opaque chambers. In northwest zone of UB, carbon equivalents of proteins and carbohydrates in surficial sediments were the same order as in hypertrophic ecosystems, whereas ammonium and phosphate released from sediment greatly exceeded the allochthonous sources. Management of municipal wastewater is required to remediate this chronic pollution.

Use of biomarkers in resident organisms as a tool for environmental monitoring in a cold coastal system, Tierra del Fuego Island.

Antioxidant status of Nacella (P) magellanica and Mytilus edulis related with heavy metal in sediment and tissues were analysed in five stations close to Ushuaia city in winter and spring. The principal component analysis produced a two-dimensional pattern of the degree of similarity between sites. The Industrial-Urban Contamination Index (IUCI) showed that the Industrial Zone (IZ) and Oil Marine Station (OMS) represent areas with anthropic inputs. Heavy metals have differential association with biomarkers depending on the species. In limpets, digestive gland presented major activities of enzyme defence in winter and gonads have shown higher values of Catalase (CAT) during spring while lipid peroxidation (LPO) presented higher values in IZ. For mussels CAT and LPO increased in spring time. For superoxide dismutase (SOD) peaks have been detected in IZ and NW stations for winter. Differences in biomarker responses due to seasons did not influence the grouping of the sites into references and contaminated groups.

First morphogenetic identification of the fungal pathogen Colletotrichum musae (Phyllachoraceae) from imported bananas in Saudi Arabia.

Colletotrichum musae is the causal agent of anthracnose in banana fruits; infection by this fungal pathogen results in severe post-harvest losses. Eleven C. musae isolates were obtained from infected imported banana fruit samples with anthracnose lesions collected from different markets in Riyadh, Saudi Arabia. The pathogenic, morphological, cultural, and molecular characteristics of these C. musae isolates were evaluated. The cultures had characteristic fast-growing sparse aerial mycelia that were white, with copious cinnamon conidial masses, conidia usually elliptical, and setae absent. An inoculation test was used to determine whether isolates could cause anthracnose symptoms on banana fruits. Necrotic lesions developed and orange-colored spore structures were later observed on these lesions. Microsatellite-primed PCR (MP-PCR) was used to identify genetic variation among the C. musae isolates. The dendrogram obtained from cluster analysis of the MP-PCR fingerprints revealed a great deal of homogeneity among the isolates, shown by the formation of two clusters. Intraspecific similarity among the C. musae isolates ranged from 83 to 100%. This is the first report demonstrating morphological and genetic variation within a population of C. musae in Saudi Arabia.

Evaluation of sublethal biomarkers in Litopenaeus vannamei on foodborne exposure to methyl parathion.

Sublethal effects of foodborne exposure to methyl parathion (0.62 and 1.31 microg methyl parathion*g(-1) dry weight of food) on juveniles of Litopenaeus vannamei using integrated biochemical (acetylcholinesterase (AChE) and ATPases) and physiological (feeding rate (FR), egestion rate (ER), and hepatosomatic index (HI)) biomarkers were evaluated. The HI was significantly higher in controls than in pesticide treatments. The FR was significantly lower in controls than in pesticide treatments while no significant differences were detected in the ER. AChE activity was significantly higher in controls than in pesticide treatments (control = 0.11 +/- 0.02; solvent control = 0.11 +/- 0.03; 0.62 = 0.07 +/- 0.01; 1.31 = 0.08 +/- 0.02 microM*min(-1)*mgprotein(-1)). The total-ATPase activity was significantly lower in controls than in pesticide treatments (control=77.90+/-12.41; solvent control = 83.69 +/- 22.05; 0.62 = 110.03 +/- 22.17; 1.31 = 121.54 +/- 19.84 microM P(i)*h(-1)*mgprotein(-1)). The Mg(2+)-ATPase activity was significantly higher in treatments than in controls (control = 65.14+/-10.76; solvent control = 75.12 +/- 21.10; 0.62 = 100.53 +/- 20.97; 1.31 = 108.94 +/- 17.26 microM P(i)*h(-1)*mgprotein(-1)). Finally, the results obtained for the Na(+)/K(+)-ATPase activity were significantly higher in control and in 1.31 than in solvent control and in 0.62 (control = 14.06+/-2.63; solvent control=7.30 +/- 4.13; 0.62 = 7.60 +/- 3.81; 1.31 = 13.42 +/- 2.88 microM P(i)*h(-1)*mgprotein(-1)). The results in this study showed that pulse exposures to methyl parathion via food could elicit measurable effects on the marine shrimp L. vannamei, indicating that foodborne exposure can be a reliable toxicological procedure and, if combined with pulse exposures, could also simulate more realistic exposure scenarios.

Heavy metal concentrations in litteral sediments from the Beagle Channel, Tierra del Fuego, Argentina.

For the first time the concentration of trace metals (Fe, Pb, Cu, Zn, Cd and total Hg) of sediments from the coastal zone of the Beagle Channel (Tierra del Fuego, in Southern Argentina) were measured. Atomic absorption spectrophotometry was utilized in order to determine the metal contents. The level of metals as observed in the sediments was recognized as the natural background, even though the use of normalization of lead, copper, and zinc to iron allowed the identification of the main sources of metal pollution for this environment. In order to develop future environmental monitoring programmes for the area of Ushuaia city and the Beagle Channel, the present results need to be considered.

Chronic toxicity of ethyl parathion and isobutoxyethanol ester of 2,4-dichlorophenoxyacetic acid to estuarine juvenile and adult crabs.

The chronic toxicity of ethyl parathion and isobutoxyethanol ester of 2,4-dichlorophenoxyacetic acid was determined for the crabs Uca uruguayensis and Chasmagnathus granulata collected in Argentina in 1989. Parathion toxicity was more time-dependent than 2,4-D. Four-week LC50 values for parathion were size and species independent, as expected under chronic exposure conditions. As shown in previous studies, the opposite was noted when crabs were exposed to acute exposure. Parathion was much more toxic than 2,4-D, in all cases. Also, parathion exerted a very much lower chronic lethal effect than other pesticides at a fraction of the respective acute LC50. A different susceptibility between sexes was found in C. granulata exposed to 2,4-D.

Description and host relationships of Polymorphus spindlatus n. sp. (Acanthocephala: Polymorphidae) from the heron Nycticorax nycticorax in Peru.

Polymorphus spindlatus n. sp. is described from the black-crowned night heron, Nycticorax nycticorax, in Lake Titicaca, Peru. It is distinguished from all 27 known species of the subgenus Polymorphus by its spindle-shaped proboscis and its trunk shape, the anterior 2/3 of which is ovoid, tapering into a tubular posterior end. It resembles Polymorphus brevis (=Arhythmorhynchus brevis), which is, however, longer and considerably more slender, and has smaller and more numerous proboscis hooks per row and smaller eggs. It is separated also from Polymorphus swartzi, Polymorphus striatus, Polymorphus contortus, and Polymorphus cincli by its proboscis armature (usually 18 longitudinal rows of 11-13 hooks each), among other characters. Histopathological sections of host tissue show well defined localized damage including hemorrhaging with subsequent phagocyte cell migration (granular tissue). The lumen of the host intestine is obstructed and villi show compression. The proboscis of P. spindlatus extends through the intestinal mucosa and submucosa, displacing the smooth muscle layers of the muscularis externa. Fibrosis also was observed.