Prenatal analysis of the insulin receptor gene in a family with leprechaunism

We report on the prenatal diagnosis of a fetus at risk of leprechaunism. We had previously determined the nature of the causative mutation in the insulin receptor gene in this family. The mutation removes a restriction site for the enzyme Mbo II. Genomic DNA was extracted from a chorionic villus sample and the 3′ half of exon 2 was amplified by the polymerase chain reaction (PCR) followed by restriction digest. Using this method, we correctly predicted an unaffected child.     

The Estuarine Component of the Us E.P.A.'S Environmental Monitoring and Assessment Program

The US Environmental Protection Agency's Office of Research and Development has initiated the Environmental Monitoring and Assessment Program (EMAP) to monitor status and trends in the condition of the nation's near coastal waters, forests, wetlands, agro-ecosystems, surface waters, deserts and rangelands. the programme is also intended to evaluate the effectiveness of Agency policies at protecting ecological resources occurring in these systems. Monitoring data collected for all ecosystems will be integrated for regional and national status and trends assessments. the near coastal component of EMAP consists of estuaries, coastal waters, and the Great Lakes. Near coastal ecosystems have been regionalized and classified, and an integrated sampling strategy has been developed. EPA and NOAA have agreed to coordinate and, to the extent possible, integrate the near coastal component of EMAP with the NOAA National Status and Trends Program. A demonstration project was conducted in estuaries of the mid-Atlantic region (Chesapeake Bay to Cape Cod) in the summer of 1990. in 1991, monitoring continued in mid-Atlantic estuaries and was initiated in estuaries of a portion of the Gulf of Mexico. Preliminary results indicate: there are no insurmountable logistical problems with sampling on a regional scale; several of the selected indicators are practical and sensitive on the regional scale; and an efficient effort in future years will provide valuable information on condition of estuarine resources at regional scales.     

Female control of extra-pair fertilization in tree swallows

Summary In a Canadian population of tree swallows, Tachycineta bicolor, DNA fingerprinting has previously shown that half of all broods contain many offspring resulting from extra-pair copulations (EPCs), whereas the other half contain only legitimate offspring. This bimodal pattern of extra-pair paternity might be due to variation in the effectiveness of male paternity guards, variation in female ability to resist EPCs, and/or variation in female pursuit of EPCs. Here we report experimental evidence for female control of copulations and fertilizations and the occurrence of two alternative copulation strategies among females in this population. Ten paired male tree swallows were removed on the day their mates laid the first egg. Replacement males took over the nestbox within 0.5–23 h and attempted to copulate with the widowed female. Assuming that eggs were fertilized approximately 24 h prior to laying, the first two eggs were fertilized before the male was removed, while the third and subsequent eggs could potentially be fertilized by the replacement male. Fingerprinting revealed that the first two eggs were sired by the resident males in five nests and by extra-pair males in the remaining five nests. The widows that had been faithful to their initially chosen mate rejected copulation attempts by the replacement male until most of the eggs had been laid. Consequently, nearly all eggs laid by these females were sired by the original male. The widows that had been unfaithful prior to male removal copulated sooner with the replacement male than females that were faithful to their mate. However, these replacement males also had a very low fertilization success; most eggs were sired by males that were not associated with the nest. This is consistent with the situation in non-experimental nests where unfaithful females copulate with their mate at the same rate as faithful females, yet unfaithful females have a majority of offspring sired by extra-pair males. We conclude that fertilization patterns to a large extent are determined by the female through active selection and rejection of copulation partners, though our results also allow some speculation that females have control over sperm competition. Female copulation tactics are probably determined some currently unknown fitness benefits of having the offspring sired by particular males.Correspondence to: Raleigh J. Robertson     

Sulfide-oxidizing bacteria in the burrowing echinoid,Echinocardium cordatum (Echinodermata)

Symbiotic filamentous bacteria thrive in the intestinal caecum of the deposit-feeding echinoid Echinocardium cordatum. Specimens of E. cordatum were collected at Wimereux (Nord Pas-de-Calais, France) in 1991. Their symbiotic bacteria build nodules by forming multilayered mats around detrital particles that enter the caecum. The morphological features of the bacteria are those of Thiothrix, a sulfide-oxidizing genus. The filaments, which may form rosettes, are sheathed and made by a succession of hundreds of rod-shaped bacteria which store elemental sulfur in the presence of external sulfide. Live bacteria are restricted to the outer layers of the nodules. Their sulfide-oxidizing activity was investigated, using a Biological Oxygen Monitor, by measuring the O₂-consumption when reduced sulfur compounds are provided. They oxidize thiosulfate and sulfide. Optimal sulfide oxidation occurs at intermediary pO₂ (100 to 160 M O₂l^-1). Spectrophotometry has confirmed that the sulfur content of the filamentous symbiotic sulfideoxidizing bacteria depends on the presence of external sulfide. This is the first report of symbiotic intradigestive Thiothrixspp.-like bacteria; it lengthens the list of symbioses between sulfide-oxidizing bacteria and invertebrates from sulfide-rich habitats.     

Enhancement of PAH biomineralization rates by cyclodextrins under Fe(III)-reducing conditions

Amendment of a soil slurry with low concentrations of a cyclodextrin, hydroxypropyl-beta-cyclodextrin (HPCD), (0.05-0.5 g l(-1)) increased the phenanthrene mineralization rate of a microbial consortium by 25% under Fe(III)-reducing conditions. Although a higher concentration (5.0 g l(-1)) resulted in a faster initial rate of mineralization, mineralization ceased after 25 days with maximum mineralization 17% lower than the control (no HPCD). At lower HPCD concentrations, mineralization was still taking place at day 76. Although pH should affect Fe(III) solubility, mineralization rates at pH 6.0 and 8.0 were comparable. Decreasing the temperature reduced the extent and rate of mineralization, but mineralization rates at 10 degrees C were still 60% of that obtained at 30 degrees C.     

Determination of the compositional change (1999–2006) in the pine forests of British Columbia due to mountain pine beetle infestation

The current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreak in British Columbia and Alberta is the largest recorded forest pest infestation in Canadian history. We integrate a spatial hierarchy of mountain pine beetle and forest health monitoring data, collected between 1999 and 2006, with provincial forest inventory data, and generate three information products representing 2006 forest conditions in British Columbia: cumulative percentage of pine infested by mountain pine beetle, percentage of pine uninfested, and the change in the percentage of pine on the landscape. All input data were formatted to a standardized spatial representation (1 ha minimum mapping unit), with preference given to the most detailed monitoring data available at a given location for characterizing mountain pine beetle infestation conditions. The presence or absence of mountain pine beetle attack was validated using field data (n?=?2054). The true positive rate for locations of red attack damage over all years was 92%. Classification of attack severity was validated using the Kruskal gamma statistic (γ?=?0.49). Error between the survey data and field data was explored using spatial autoregressive (SAR) models, which indicated that percentage pine and year of infestation were significant predictors of survey error at α?=?0.05. Through the integration of forest inventory and infestation survey data, the total area of pine infested is estimated to be between 2.89 and 4.14 million hectares. The generated outputs add value to existing monitoring data and provide information to support management and modeling applications.     

Crystal structure and density functional theory studies of toxic quinone metabolites of polychlorinated biphenyls

Lower chlorinated polychlorinated biphenyls (PCBs) are readily metabolized via hydroxylated metabolites to reactive PCB quinones. Although these PCB metabolites elicit biochemical changes by mechanisms involving cellular target molecules, such as the aryl hydrocarbon receptor, and toxicity by interacting with enzymes like topoisomerases, only few PCB quinones have been synthesized and their conformational properties investigated. Similar to the parent compounds, knowledge of the three-dimensional structure of PCB quinones may therefore be important to assess their fate and risk. To address this gap in our knowledge, the gas phase molecular structure of a series of PCB quinones was predicted using HF/3-21G, B3LYP/6-31G?? and UB3LYP/6-311G?? calculations and compared to the respective solid state structure. All three methods overestimated the Cl-C bond length, but otherwise provided a reasonable approximation of the solid state bond angles and bond lengths. Overall, the UB3LYP/6-311G?? level of theory yielded the best approximation of the molecular structure of PCB quinones in the solid state. Chlorine addition at the ortho position of both rings was found to increase the dihedral angle of the resulting quinone compound, which may have important implications for their interaction with cellular targets and, thus, their toxicity.     

Metals emitted from heavy-duty diesel vehicles equipped with advanced PM and NOX emission controls

Emission factors for elemental metals were determined from several heavy-duty diesel vehicles (HDDV) of 1998–2007 vintage, operating with advanced PM and/or NO_X emissions control retrofits on a heavy-duty chassis dynamometer, under steady state cruise, transient, and idle conditions. The emission control retrofits included diesel particulate filters (DPF): catalyzed and uncatalyzed, passive and active prototype vanadium- or zeolite-based selective catalytic reduction (SCR) systems, and a catalyzed DPF fitted on a hybrid diesel electric drive vehicle. The prototype SCR systems in combination with DPF retrofits are of particular interest because they represent the expected emissions controls for compliance with PM and NO_X regulations in 2010. PM samples from a full-exhaust dilution tunnel were collected on bulk filters, and on a Personal Cascade Impactor Sampler (PCIS) for total and water-soluble elemental analysis. All the DPFs significantly reduced emissions of total trace elements (>85% and >95% for cruise and for the Urban Dynamometer Driving Schedule (UDDS), respectively). However, we observed differences in the post-retrofit metals emissions due to driving cycle effects (i.e., exhaust temperature) and type of retrofit. In general, the metals emissions over cruise conditions (which leads to higher exhaust temperatures) were substantially different from the emissions over a transient cycle or while idling. For instance, during cruise, we observed higher levels of platinum (1.1 ± 0.6–4.2 ± 3.6 ng km^?1) for most of the retrofit-equipped vehicle tests compared to the baseline configuration (0.3 ± 0.1 ng km^?1). The vanadium-based DPF + SCR vehicle during cruise operation exhibited emissions of vanadium (562 ± 265 ng km^?1) and titanium (5841 ± 3050 ng km^?1), suggesting the possible release of actual SCR wash-coat (V₂O₅/TiO₂) from the catalyst under the higher temperatures characteristic of cruise operation. The vanadium emissions exhibited a bi-modal mass size distribution, with modes at <0.25 μm and 1.0–2.5 μm size ranges for the vanadium-based SCR system. For the DPF + SCR systems, a greater fraction of the metal emissions from the zeolite-based system is water-soluble compared to emissions from the vanadium-based system.