Development of an enzyme-linked immunosorbent assay for screening contamination by chlorophenols in environmental waters

The development of an immunoassay for screening contamination by chlorophenols is presented. Two haptens were synthesized and conjugated to immunizing proteins to raise rabbit polyclonal antibodies. The antibody-coated format (direct) gave better sensitivity than the conjugate-coated format (indirect) if 2,4,6-trichlorophenol is used as target analyte. The measurement range was 86.4 microg l(-1) to 0.7 microg l(-1), with an average I50 of 7.8 microg l(-1) and a detection limit of 0.2 microg l(-1). The assay detects the presence of trichloropyridinol and other chlorophenols such as di-, tetra- and pentachlorophenols constituting thus a suitable tool for the early warning of the presence of such family contaminants. The optimized method permits the detection of the most important chlorophenols in a fast and reproducible way using no more than one antibody and a single assay. The results achieved with water samples spiked with different chlorophenols fit with a multiple linear regression model when expressing the total concentration of chlorophenols as equivalent of 2,4,6-trichlorophenol (P < 0.01), demonstrating the usefulness of the assay as a screening tool to detect contamination by chlorophenols.     

Learning Machines Applied to Potential Forest Distribution

The clearing of forests to obtain land for pasture and agriculture and the replacement of autochthonous species by other faster-growing varieties of trees for timber have both led to the loss of vast areas of forest worldwide. At present, many developed countries are attempting to reverse these effects, establishing policies for the restoration of older woodland systems. Reforestation is a complex matter, planned and carried out by experts who need objective information regarding the type of forest that can be sustained in each area. This information is obtained by drawing up feasibility models constructed using statistical methods that make use of the information provided by morphological and environmental variables (height, gradient, rainfall, etc.) that partially condition the presence or absence of a specific kind of forestation in an area. The aim of this work is to construct a set of feasibility models for woodland located in the basin of the River Liébana (NW Spain), to serve as a support tool for the experts entrusted with carrying out the reforestation project. The techniques used are multilayer perceptron neural networks and support vector machines. Their results will be compared to the results obtained by traditional techniques (such as discriminant analysis and logistic regression) by measuring the degree of fit between each model and the existing distribution of woodlands. The interpretation and problems of the feasibility models are commented on in the Discussion section.     

High-impact conservation: invasive mammal eradications from the islands of western México

Islands harbor a disproportionate amount of the earth's biodiversity, but a significant portion has been lost due in large part to the impacts of invasive mammals. Fortunately, invasive mammals can be routinely removed from islands, providing a powerful tool to prevent extinctions and restore ecosystems. Given that invasive mammals are still present on more than 80% of the world's major islands groups and remain a premier threat to the earth's biodiversity, it is important to disseminate replicable, scaleable models to eradicate invasive mammals from islands. We report on a successful model from western México during the past decade. A collaborative effort between nongovernmental organizations, academic biologists, Mexican government agencies, and local individuals has resulted in major restoration efforts in three island archipelagos. Forty-two populations of invasive mammals have been eradicated from 26 islands. For a cost of USD 21,615 per colony and USD 49,370 per taxon, 201 seabird colonies and 88 endemic terrestrial taxa have been protected, respectively. These conservation successes are a result of an operational model with three main components: i) a tri-national collaboration that integrates research, prioritization, financing, public education, policy work, capacity building, conservation action, monitoring, and evaluation; ii) proactive and dedicated natural resource management agencies; and iii) effective partnerships with academic researchers in Mexico and the United States. What is now needed is a detailed plan to eradicate invasive mammals from the remaining islands in the region that integrates the needed additional financing, capacity, technical advances, and policy issues. Island conservation in western Mexico provides an effective approach that can be readily applied to other archipelagos where conservation efforts have been limited.     

Organochlorines and endometriosis: a mini-review

Organochlorines (polychlorinated biphenyls and dioxin-like compounds) are suspected to play a role in the etiopathogenesis of endometriosis. This hypothesis, based on experimental data, has been circulating for years in the scientific community and several epidemiologic surveys have attempted to obtain confirmatory human data. The purpose of this mini-review is to provide an overview of the twelve epidemiological studies that have assessed the relationship between endometriosis and organochlorine exposure. Several studies did not observe a significant association between peritoneal endometriosis and organochlorines. The deep nodular form of endometriosis appears associated with a higher serum level of both dioxin-like compounds and polychlorobiphenyls. The type of control women, the nature of the chemicals measured, and the definition of the disease could modulate the ability to detect the possible relationship between endometriosis and organochlorine exposure.     

Semilobar holoprosencephaly in a 46,XY female fetus

We report the prenatal echographic diagnosis of holoprosencephaly (HPE) at 11 weeks' gestation. Fetopathological examination revealed an unusual variant of semilobar HPE with middle interhemispheric fusion associated with sex-reversal: 46,XY normal male karyotype, normal external and internal female genitalia and streak gonads. Copyright © 2001 John Wiley & Sons, Ltd.     

Increased acidification in the rhizosphere of cactus seedlings induced by Azospirillum brasilense

Acidification of the rhizosphere of cactus seedlings (giant cardon, Pachycereus pringlei) after inoculation with the plant growth-promoting bacterium Azospirillum brasilense Cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. While ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. On the other hand, nitrate increased pH of the rhizosphere, but combined with the bacterial inoculation, increase in pH was significantly smaller. Bacterial inoculation with ammonium enhanced plant growth.     

Regional patterns of microsatellite variation in <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> from the Iberian Peninsula

The Almería-Oran Oceanographic Front (AOOF) has been proposed as an effective marine barrier to gene flow between the NE Atlantic Ocean and the Mediterranean Sea for several species. Previous studies using allozymes and mitochondrial DNA have reported a scenario of secondary intergradation between populations of Mytilus galloprovincialis from those basins, with the allelic frequencies of some loci showing abrupt clinal patterns across the AOOF. In this study, we aimed at testing the congruence between six neutral polymorphic microsatellites versus previous data on allozymes and mtDNA-RFLPs, at depicting the population structure of this species in the Iberian Peninsula. Microsatellite genotyping was scored on 17 samples of mussels collected in the Iberian coast, including some areas not sampled before. Microsatellites exhibited larger intrabasin diversity (F _SC = 1.72%, ), similar interbasin differentiation (F _CT = 2.81%) and fewer allelic clines than allozymes or mtDNA haplotypes. These results fully support the scenario of secondary intergradation with some ongoing gene flow between basins, as proposed in previous analyses. Moreover, this congruence between markers and analyses separated by a 12-year period (1988–2000) confirm the temporal stability of this marine barrier at shaping the Iberian phylogeographic break in M. galloprovincialis. In addition, the genetic continuity between the NE Atlantic (Portugal) and the Alboran Sea seems to be warranted across the Gulf of Cadiz and the Gibraltar strait after the present microsatellite data. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.