2,4,6-Trinitrotoluene detection using recombinant antibodies

The ability to detect low levels of 2,4,6-trinitrotoluene (TNT) in aqueous samples is important due to the toxicity of both TNT and its breakdown products. We have been characterizing recombinant anti-TNT antibodies isolated from the Griffin library of phage displayed scFvs by selection for binders to the TNT-surrogate 2,4,6-trinitrobenzene (TNB) coupled to the protein bovine serum albumin. Two candidate antibody fragments, TNB1 and TNB2, were isolated and evaluated by ELISA for their ability to bind to TNB coupled to the protein ovalbumin. Competition ELISA was then used to demonstrate antibody fragment binding to TNT in solution and to examine cross-reactivity towards several TNT-related compounds and other explosives. Both recombinant antibody fragments were incorporated into a continuous flow assay for the detection of TNT. TNB2, the best single chain antibody, showed a limit of detection of 1 ng ml(-1), comparable to a commercially available anti-TNT antibody in the same assay format.     

Changes in Sediment Sources following Wildfire in Mountainous Terrain: A Paired–Catchment Approach,British Columbia,Canada

This paper describes a study examining the potential of mineral magnetic, geochemical and organic properties to determine if a 2003 wildfire in a catchment in British Columbia, Canada, caused a change in the sources of the suspended sediment transported in the channel relative to a nearby unburnt (reference) catchment. The results show that some of the properties offer the potential to determine sediment sources in the unburnt catchment. However, the 2003 wildfire modified the concentrations of some properties and this can either compromise or enhance their ability as tracers in the burnt catchment. At present, the source tracing results are inconclusive. This has implications for the use of certain properties as fingerprints and raises important issues about approaches to sediment source identification.     

Effect of Sequential Mixing and Compounding Conditions on Cellulose Acetate/Layered Silicate Nanocomposites

Injection molded nanocomposites have been successfully fabricated from cellulose acetate (CA), eco-friendly triethyl citrate (TEC) plasticizer, and organically modified clay with and without maleic anhydride grafted cellulose acetate butyrate (CAB-g-MA) as a compatibilizer. The effects of processing conditions such as mixing methods, pre-plasticizing times, extruder retention times (RT) and addition of compatibilizer on the performance of these nanocomposites have been evaluated. The cellulosic plastic with CA/TEC (80/20 wt%) was used as the polymer matrix for nanocomposite fabrication. The morphologies of these nanocomposites were evaluated through X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies. The mechanical properties of the nanocomposites were measured and have been correlated with the XRD and TEM observations. From all of the sequential mixing methods used, powder–powder mixing leads to the most transparent nanocomposites. Cellulosic plastic-based nanocomposites obtained using increased pre-plasticizing times and RT showed better exfoliated structures. In the system containing compatibilizer, the minimum retention time required for obtaining almost completely exfoliated hybrid nanocomposites was shorter than in the system without compatibilizer.     

Case study of ex situ remediation and conversion to a combined in situ/ex situ bioremediation approach at an oxygenated gasoline release site

In response to an oxygenated gasoline release at a gas station site in New Hampshire, a temporary treatment system consisting of a single bedrock extraction well, a product recovery pump, an air stripper, and carbon polishing units was installed. However, this system was ineffective at removing tertiary butyl alcohol from groundwater. The subsequent remedial system design featured multiple bedrock extraction wells and an ex situ treatment system that included an air stripper, a fluidized bed bioreactor, and carbon polishing units. Treated effluent was initially discharged to surface water. Periodic evaluation of the remediation system performance led to system modifications, which included installing an additional extraction well to draw contaminated groundwater away from an on‐site water supply well, adding an iron and manganese pretreatment system, and discharge of treated effluent to an on‐site drywell. Later, the air stripper and carbon units were eliminated, and an infiltration gallery was installed to receive treated, oxygenated effluent in order to promote flushing of the smear zone and in situ bioremediation in the source area. This article discusses the design, operation, performance, and modifications to the remediation system over time, and provides recommendations for similar sites. © 2007 Wiley Periodicals, Inc.     

Pelagic crinoids (Roveacrinida, Crinoidea) discovered in the Neogene of Poland

Until recently, it has been assumed that pelagic crinoids, the roveacrinids (Roveacrinida, Crinoidea), became extinct during the Cretaceous-Paleogene boundary event. Recent finds of well-preserved roveacrinidal remains (brachials and radials) in the Danian (Early Paleogene) of Poland showed that they survived into the earliest Cenozoic. This group was thus characterized as a "dead clade walking". Here, we present fossil evidence that these pelagic crinoids survived in Poland until at least the Middle Miocene (Badenian, ca. 14?Myr ago)-more than 50?Myr after their supposed extinction. These Miocene roveacrinids constitute the first documented evidence of Roveacrinida in strata of Neogene age, thus prolonging the stratigraphic range of pelagic crinoids. This find characterizes the order as a "Lazarus taxon" rather than a "dead clade walking" group.     

A methodological proposal for the evaluation of farmer’s adaptation to climate variability, mainly due to drought in watersheds in Central America

The current study shows the process and the results of a methodology proposed to contribute with the issue of how to evaluate the adaptation to climate variability and future climate change. The proposed methodology consists of a standard to evaluate farmer’s adaptation to climate variability, mainly due to drought in watersheds in Central America; and was created with contributions from experts and professionals around this region. The phases for this process were: (1) literature review about the topic, (2) development of a preliminary standard, (3) expert interviews for the evaluation of this preliminary standard, (4) construction of a standard to evaluate the issue of adaptation to climate variability emphasizing drought through contributions from experts and their preliminary evaluations, (5) applicability test of this standard for the evaluation of climate variability under real conditions and (6) application of this standard through a case study in the Aguas Calientes river sub-watershed in Nicaragua, which permanently undergoes drought problems and climate variability. This standard has five main principles that go from the general, considering regional and national policies and institutionalism, to the specifics at the level of watersheds. In addition to those principles, the standard contains ten criteria, 26 indicators and 51 verifiers distributed among the main five principles. In the process for testing this standard in the Aguas Calientes river watershed in Nicaragua, the score for the general applicability to this standard was middle-level (score of 3 in a scale of 1 to 5), although, for the main principles of this standard, the score was four (high).     

Microstructures of Antarctic cidaroid spines: diversity of shapes and ectosymbiont attachments

The echinoderm endoskeleton, located in the connective layer of the tegument, is organized into a three-dimensional mesh, the stereom. Among echinoids, the cidaroids depart from this pattern, and the shaft of the spine lacks an epidermis. Thus, the spines lack antifouling protection, allowing ectosymbionts such as bryozoans and foraminiferans to attach. This raises a question about the adaptive role of the cortical layer of the stereom. This study examined the micro- and mesostructure of the spines of 11 cidaroid species collected in the Weddell Sea and Drake Passage, and the nature of their ectosymbiont attachments. Scanning electron microscopy was used to characterize the cortex surface and X-ray micro computed tomography (μCT) to describe the symbiont attachments. Spine microstructure features provide a useful taxonomic character for distinguishing among three species in the genus Ctenocidaris, and challenge a previous parasitic interpretation of cortical filaments on the spines of Rhynchocidaris triplopora. Ectosymbiont attachments were classified as Anchoring, Molding, Cementing, or Corroding. The study suggests that some microstructure features may be protective, keeping the ectosymbionts away from the cortex and loosely attached at intervals along the shaft of the spine, while other micro-structures facilitate attachment over considerable areas of the shaft. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

No male agonistic experience effect on pre-copulatory mate choice in female earwigs

Mating with dominant males may confer considerable benefits, but also incur significant costs, hence intrasexual competitiveness is a likely target of mate choice. In addition to established modes of mate assessment, females may use cues or signals associated with agonistic experience effects to assess the relative competiveness of males. Experience effects, where the outcome of a fight increases the likelihood of a similar outcome in subsequent fights, may result from an animal’s altered state after conflict, but can also arise from strategic rival use of information perceived about this altered state. While females may similarly use this information in mate choice decisions, this potential consequence of male–male conflict has largely been neglected. Here, we investigate the effects of experience on subsequent agonistic performance in the earwig Euborellia brunneri by imposing winning or losing experiences on males and rematching them with naïve, size-matched rivals. We reveal a strong loser effect in subsequent fights, with nearly all previous “losers” losing against new rivals. In contrast, we found no equivalent winner effect, with previous “winners” exhibiting no increased likelihood of winning. We subsequently test whether the effects of male agonistic experience extend to pre-copulatory female mate choice. We show that females, when allowed to choose between naïve males and “winners” or “losers”, do not discriminate between males based on their recent agonistic experience. Therefore, while fighting history can play an important role in male–male interactions, females may not attend to this information.     

The presence of females modulates the expression of a carotenoid-based sexual signal

Several environmental factors have been shown to shape the pattern of investment of carotenoids into the expression of sexual signals. Surprisingly, the impact of the social environment has been neglected. If a carotenoid-based sexual trait is used by females to choose a mate or by males to assess the quality of potential competitors for mates, males, in the presence of females, should upregulate expression of the trait. We tested this hypothesis in male zebra finches that were housed either with females or in a male-only social environment. Additionally, to investigate whether the social modulation of the expression of a sexual trait depends on the physiological need of carotenoids, we challenged half of the males with Escherichia coli lipopolysaccharide (LPS). We found that the social environment modulated the expression of bill color, with males kept in the presence of females harboring a redder bill at the end of the 3 weeks that the experiment lasted. Males injected with LPS showed duller bill color regardless of the presence of females, and social interactions with females result in upregulated bill color similarly for phosphate-buffered saline (PBS) and LPS males. Thus, social environment and immune activation had an additive effect on the expression of bill color. The effect of social environment on plasma carotenoids was less clear. Indeed, a first replicate of the entire experiment showed that both immune challenge and social context affected bill color, with a negative effect of immune challenge and a positive effect of the presence of females on circulating carotenoids. However, a second replicate of the experiment showed only a negative effect of the immune challenge. These results, therefore, suggest that the social environment can affect the expression of carotenoid-based sexual traits under both benign and carotenoid-demanding conditions. Whatever the signaling function of bill color (female mate choice or male–male competition for mates), the observed flexibility may be adaptive because the expression of the signal can be modulated depending on the expected rewards or costs associated with the presence or absence of females. Nevertheless, the mechanisms underlying such an effect are still unknown.     

Metals and emerging contaminants in groundwater and human health risk assessment

Environmental Science and Pollution Research - Groundwaters are normally consumed without previous treatment and therefore the monitoring of contaminants in order to guarantee its safety is...