Differences in natural infections of two mortality-related trematodes in lesser scaup and American coot

Populations of North American waterbirds, particularly lesser scaup, have been declining due to habitat disturbance, changing food resources, contaminants, bad water quality, and competition. However, epizootic diseases, including parasitism, may also play an important role in further decline. Trematode-associated mortality of migrating waterbirds, mainly American coot and lesser scaup, has been occurring in the Upper Mississippi River National Wildlife and Fish Refuge since 2002. We examined the levels of infective stages of Cyathocotyle bushiensis and Sphaeridiotrema globulus in the invasive, intermediate host snail, Bithynia tentaculata, during the fall of 2005 and compared these to infection levels in moribund or dead bird hosts. Our results show different infection levels of these 2 parasites in the 2 bird species; C. bushiensis is found more frequently in coot, and S. globulus is more common in scaup. This result is interesting because both bird species are presumed to forage on the same snail population and thus should be experiencing the same extent of exposure. These differences in infections could be attributed to differences in resources of gastrointestinal tracts of coot and scaup, or host resistance. Alternatively, differences in feeding behaviors of coot and scaup may also contribute to differential infections of the 2 trematodes.     

The dilemma of foraging herbivores: dealing with food and fear

For foraging herbivores, both food quality and predation risk vary across the landscape. Animals should avoid low-quality food patches in favour of high-quality ones, and seek safe patches while avoiding risky ones. Herbivores often face the foraging dilemma, however, of choosing between high-quality food in risky places or low-quality food in safe places. Here, we explore how and why the interaction between food quality and predation risk affects foraging decisions of mammalian herbivores, focusing on browsers confronting plant toxins in a landscape of fear. We draw together themes of plant–herbivore and predator–prey interactions, and the roles of animal ecophysiology, behaviour and personality. The response of herbivores to the dual costs of food and fear depends on the interplay of physiology and behaviour. We discuss detoxification physiology in dealing with plant toxins, and stress physiology associated with perceived predation risk. We argue that behaviour is the interface enabling herbivores to stay or quit food patches in response to their physiological tolerance to these risks. We hypothesise that generalist and specialist herbivores perceive the relative costs of plant defence and predation risk differently and intra-specifically, individuals with different personalities and physiologies should do so too, creating individualised landscapes of food and fear. We explore the ecological significance and emergent impacts of these individual-based foraging outcomes on populations and communities, and offer predictions that can be clearly tested. In doing so, we provide an integrated platform advancing herbivore foraging theory with food quality and predation risk at its core.     

μ-H-Bridged Bicyclo[3.3.3]undecyl Cations. Theoretical Calculations of Physical and Chemical Properties

7-H-Bridged carbocations 1 and 2, which are still unknown experimentally, are structures with fascinating possibilities as intermediates for the synthesis of very strained in-bicyclic and tricyclic alkanes and alkenes. They are also expected to possess record high pK_a values. In conjunction with our experimental program to try to prepare 1 and 2, we have carried out ab initio calculations on these structures and various reference compounds, with the aim of assessing just how stable these cations might be, and what physical and chemical properties they might possess. The results of these studies confirm that 1 and 2 should be viable species; they have energies similar to those of the conventional out-cations, and the 7-H bond distances are not very different from those calculated for known 7-H cations. The calculated ¹H NMR chemical shift for the mu-H of 1 is -12 - 0.5 and -9.5 - 0.5 for 2, both values considerably more negative than in known 7-H cations. The possible effect of large amplitude motions of the 7-H on the ¹H NMR chemical shift was investigated and not found to be significant. The pK_as for 1 and 2 are estimated to be 17-18 with respect to an alkene conjugate base, a virtually unimaginable size for a formally alkyl cation. The paper also discusses the possibility of the 7-H being involved in the acid-conjugate base chemistry, since this is shown to be a hugely exothermic reaction. Finally, the alkenes and alkanes associated with cations 1 and 2 have been calculated, the in-alkene 7 from cation 1 is shown, for example, to possess a large steric strain, yet this structure should be accessible via deprotonation of 1 with a strong base.     

Molecular mechanics studies of dermorphin

Molecular mechanical simulations have been carried out on dermorphin. Presence of D-Ala2 at the N-terminus and L-Pro6 residue at the C-terminus indicated the probability of beta-turns. From the stereochemical considerations, three types- II', III' and V' - for the beta-turn at the N-terminus of the peptide and two types-I and III- for the C-terminus side of the peptide are possible. In our molecular mechanics calculations, we considered six folded and one extended conformations for dermorphin to asses the relative stabilities. Three of the six folded conformations are lower in energy and have the following general feature-similar in energy, three hydrogen bonds, semirigid beta-sheet segment and favorable Tyr1-Tyr5 interaction. The presence of beta-sheet structure might play a role in mu-receptor selective interaction of dermorphin.     

Chemical strategies for functional proteomics

With complete genome sequences now available for several prokaryotic and eukaryotic organisms, biological researchers are charged with the task of assigning molecular and cellular functions to thousands of predicted gene products. To address this problem, the field of proteomics seeks to develop and apply methods for the global analysis of protein expression and protein function. Here we review a promising new class of proteomic strategies that utilizes synthetic chemistry to create tools and assays for the characterization of protein samples of high complexity. These approaches include the development of chemical affinity tags to measure the relative expression level and post-translational modification state of proteins in cell and tissue proteomes. Additionally, we discuss the emerging field of activity-based protein profiling, which aims to synthesize and apply small molecule probes that monitor dynamics in protein function in complex proteomes.     

A cryptic invasion within an invasion and widespread introgression in the European water frog complex: consequences of uncontrolled commercial trade and weak international legislation

In Western Europe, many pond owners introduce amphibians for ornamental purposes. Although indigenous amphibians are legally protected in most European countries, retailers are circumventing national and international legislation by selling exotic nonprotected sibling species. We investigated to what extent non‐native species of the European water frog complex (genus Pelophylax) have become established in Belgium, using morphological, mitochondrial and nuclear genetic markers. A survey of 87 sampling sites showed the presence of non‐native water frogs at 47 locations, mostly Marsh frogs (Pelophylax ridibundus). Surprisingly, at least 19% of all these locations also harboured individuals with mitochondrial haplotypes characteristic of Anatolian water frogs (Pelophylax cf. bedriagae). Nuclear genotyping indicated widespread hybridization and introgression between P. ridibundus and P. cf. bedriagae. In addition, water frogs of Turkish origin obtained through a licensed retailer, also contained P. ridibundus and P. cf. bedriagae, with identical haplotypes to the wild Belgian populations. Although P. ridibundus might have invaded Belgium by natural range expansion from neighbouring countries, our results suggest that its invasion was at least partly enhanced by commercial trade, with origins as far as the Middle East. Also the invasion and rapid spread of Anatolian lineages, masked by their high morphological similarity to P. ridibundus, is likely the result of unregulated commercial trade. We expect that Anatolian frogs will further invade the exotic as well as the native range of P. ridibundus and other Pelophylax species elsewhere in Western and Central Europe, with risks of large‐scale hybridization and introgression.     

Attracting Common Carp to a bait site with food reveals strong positive relationships between fish density,feeding activity,environmental DNA,and sex pheromone release that could be used in invasive fish management

Measurement of environmental DNA (eDNA) is becoming a common technique to survey for rare and invasive fish due to its sensitivity and specificity. However, its utility is limited by an incomplete understanding of factors governing its sources and fates. Failure to detect eDNA is especially difficult to interpret so surveillance techniques often collect large numbers of samples across broad regions. If, however, fish could be reliably attracted to a single location where their eDNA could be easily measured that would be useful. We conducted a proof‐of‐concept study of this idea using invasive Common Carp. We monitored the distribution of radio‐tagged Carp and their eDNA across a 67 ha lake focusing at the bait site while a pheromone (Prostaglandin F_2α; PGF_2α) was also measured to determine their reproductive condition. Prior to baiting, Carp were patchily distributed and while eDNA was occasionally detectable, it was patchy and only loosely associated with moderately dense groups of fish. Further, neither Carp, nor their eDNA were consistently measurable at the bait site and surrounding region, and the pheromone was not measurable at all. However, once baiting commenced, Carp started visiting the bait site and feeding, especially at night, where eDNA levels increased 500‐fold as fish densities doubled and PGF_2α became detectable. Fish presence, eDNA and pheromone concentrations peaked at night after 6 days, strongly suggesting feeding activity was the main driver. While the presence of eDNA precisely coincided with this aggregation, levels had dropped dramatically within 5 m. PGF_2α levels dropped less rapidly and demonstrated the presence of live mature fish. We suggest that food could be used to train fish to come to locations where they otherwise are too scarce to be reliably measured, increasing their eDNA release, making them measurable, and their reproductive condition also discernable by measuring pheromones.     

Mapping Quantitative Trait Loci Controlling Milk Production in Dairy Cattle by Exploiting Progeny Testing

We have exploited ``progeny testing' to map quantitative trait loci (QTL) underlying the genetic variation of milk production in a selected dairy cattle population. A total of 1,518 sires, with progeny tests based on the milking performances of > 150,000 daughters jointly, was genotyped for 159 autosomal microsatellites bracketing 1645 centimorgan or approximately two thirds of the bovine genome. Using a maximum likelihood multilocus linkage analysis accounting for variance heterogeneity of the phenotypes, we identified five chromosomes giving very strong evidence (LOD score >/= 3) for the presence of a QTL controlling milk production: chromosomes 1, 6, 9, 10 and 20. These findings demonstrate that loci with considerable effects on milk production are still segregating in highly selected populations and pave the way toward marker-assisted selection in dairy cattle breeding.