Introduction of cob(I)alamin as an analytical tool: application to reaction-kinetic studies of oxiranes

The strongly nucleophilic cob(I)alamin, i.e. Vitamin B₁₂ with Co(III) reduced to Co(I), is introduced as a trapping agent in the determination of concentrations of electrophilic reagents. This compound was applied, in comparison with the previously used moderately reactive nicotinamide (H.J.C.F. Nelis and J.E. Sinsheimer (1981). Anal. Biochem., 115, 151.). Oxiranes, metabolites of 1-alkenes, were chosen as model electrophiles. The reagents (nicotinamide and cob(I)alamin) were evaluated in the determination of the rates of reaction toward valine methylamide, a model of N-terminal valines in hemoglobin often used for monitoring of doses in vivo of genotoxic carcinogens. The rate constants for reaction at 37°C with valine methylamide (k _VMA) determined by the cob(I)alamin and nicotinamide procedure, respectively, were for ethylene oxide (1.6, 1.7), propylene oxide (0.9, 1.1), 1,2-epoxybutane (0.7, 0.8) and 1,2-epoxyoctane (0.5, 0.6) M^?1?h^?1, decreasing with increasing number of carbons of the oxirane. Concentrations of oxiranes trapped with nicotinamide are underrated in reaction mixtures containing valine methylamide due to consumption by reaction with the competing nucleophile, a disturbance that is not observed in trapping with cob(I)alamin which reacts about 10⁵ times faster than nicotinamide. Cob(I)alamin which was demonstrated to be an efficient nucleophile for trapping of electrophiles, also in the presence of competing nucleophiles, is promising as an analytical tool in toxicological studies of reactive compounds. Furthermore, cob(I)alamin can be used to detect, measure and compare electrophilic reactivity of chemical substances, a property that is associated with genotoxic potency.     

Fertile diploid males in the ant Cataglyphis cursor: a potential cost of thelytoky?

Under the hymenopteran single-locus complementary sex-determination system, production of diploid males results from homozygosity at the sex-determiner locus. This arises when both parents transmit identical alleles at the locus to the offspring. In species reproducing asexually through thelytokous parthenogenesis, production of diploid males may also occur when the sex locus undergoes recombination and becomes homozygous in the offspring. Diploid males represent a substantial genetic load in hymenopteran populations because they often produce unviable sperm or sire sterile triploid female offspring. In the Mediterranean ant Cataglyphis cursor, the queen and workers can produce female offspring through automictic thelytokous parthenogenesis with central fusion, a mode of parthenogenesis that increases homozygosity. We report, for the first time, the presence of about 39 % of colonies producing adult diploid males (seven colonies out of 18). Overall, 8 % of adult males were diploid (12 diploid males out of the 146 males genotyped). Genotyping workers from the seven colonies producing diploid males showed that three diploid males were sons of queens and produced by thelytoky, six were probably sons of workers also produced by thelytoky and three were non-natal. Furthermore, the mating of a diploid male with two virgin queens in the laboratory led to the production of sterile triploid workers, which shows that diploid males in C. cursor are fertile, mate successfully and produce viable and functional but probably sterile female offspring. Because diploid males originate from thelytokous reproduction, they are only produced during sexual production and hence do not impair colony growth, which could explain why they are not removed at early brood stages.     

Reproductive periodicity of the scleractinian coral Lophelia pertusa from the Trondheim Fjord, Norway

Between 2002 and 2008, samples of the cold-water scleractinian coral Lophelia pertusa were collected from the Trondheim Fjord in Norway to examine reproductive periodicity. Collections were made from three locations: Tautra, (63°35.36′N, 10°31.23′E at 40–70 m), Stokkbergneset (63°28.18′N, 09°54.73′E at 110–500 m), and Røberg (63°28.88′N, 09°59.50′E at 250 m). Populations of L. pertusa from the Trondheim Fjord initiated oogenesis in January and spawning occurred from late January to early March the following year. Gametogenic cycles of the female L. pertusa samples overlapped by approximately 2 months, with oogonia visible in January, but this was not evident in the males. This paper provides the most complete gametogenic cycle to date and spawning observations for this important structure-forming species. The results from fjord populations are compared with published and preliminary data from other regions and are discussed in the context of regional differences in physical and biological variables, particularly food supply. Differences in gametogenic cycles within a single species provide a rare opportunity (especially in deep-sea species) to examine potential drivers of reproduction.     

Vole response to unintentional changes in the chemistry of GM poplars

Summary.  There is an increased interest for the use of GM trees in forestry and several commercially promising lines are now available. However, the ecological implications of the use of GM trees, e.g. effects on non-target natural enemies, have rarely been explored. The aim of this study was to determine if modification of non-defensive traits in GM poplars unintentionally can influence plant chemistry in a way that has consequences for palatability to voles. In a greenhouse experiment, we used two lines, SPS33A and SPS26, of GM hybrid poplars (Populus tremula x tremuloides) with 1.5 and 4 times, respectively, over-expression sucrose-phosphate synthase (SPS). This enzyme plays a central role in sucrose synthesis, affecting cold acclimation, mesophyll sucrose content and biomass production. As a control we used the isogenic unmodified wild type. Stems of these poplars were presented to bank voles and field voles in cafeteria experiments. The concentration of condensed tannins was higher in leaves of lines SPS33A and SPS26 than in the isogenic wild-type and the concentration of nitrogen was higher in line SPS33A than in both the wild-type and line SPS26. Although the bank voles consumed slightly less bark from SPS33A, there were no significant differences in the preference of bank vole or field vole for the different poplar lines. This indicates that the changes in plant chemistry were insufficient to produce any strong herbivore response or that alteration in tannins and nitrogen counteracted each other. Still, changes in the interactions between mammalian herbivores and GM trees are important to consider in future cost-benefits analyses of GM trees.     

Butterfly effects in mimicry? Combining signal and taste can twist the relationship of Müllerian co-mimics

Müllerian co-mimics are aposematic species that resemble each other; sharing a warning signal is thought to be mutually beneficial for the co-mimics by reducing per capita predation risk. In Batesian mimicry, edible mimics avoid predation by resembling an aposematic model species. The protection of both the model and the mimic is weakened when the mimics are abundant compared to the models. The quasi-Batesian view suggests that defended (Müllerian) co-mimics, when unequal in their defences, could also show a Batesian-like trend of increasing mortality with increasing abundance of a less defended “mimic”. We manipulated frequencies of unequally distasteful artificial co-mimics that were prey for great tits. The co-mimics had different signals (imperfect mimicry) but were equally preferred by the birds when palatable. Unexpectedly, when unpalatable, one of the signals was easier for the birds to learn to avoid. Consequently, during predator learning, the signal design of the prey strongly affected mortality of the co-mimics; there was an interaction between the signal and frequency treatments, but increasing the frequency of a less defended “mimic” did not increase co-mimic mortalities as predicted. In contrast, in a memory test that followed, the effect of signal design disappeared; if the birds had experienced high frequency of “mimics” during learning, co-mimic mortalities did subsequently increase. Since the effect of co-mimic frequencies on mortalities changed depending on the signal design of the prey and predator experience, the results suggest that mimetic relationship may be an unpredictable interplay of several factors in addition to taste and abundance.     

Four genes,morphology and ecology: distinguishing a new species of <Emphasis Type="Italic">Acesta</Emphasis> (Mollusca; Bivalvia) from the Gulf of Mexico

There is currently an active scientific debate about the most correct and efficient way to identify species. To date, few studies in the marine realm have combined the available taxonomic methods. In this study we have used morphology, ecology and molecular analyses to identify a new species within the bivalve genus Acesta. All four genes studied (12S, 16S, Cytb, COI) suggested that a common cold-seep species in the Gulf of Mexico, A. bullisi, should be divided into two distinct species. This conclusion was supported by morphological traits and by observations of ecological distribution. A. oophaga Järnegren, Schander and Young n. sp. is described here, and A. bullisi Vokes (Tulane Stud Geol 2:75–92, 1963) is re-described. This study shows that DNA barcoding in combination with traditional morphological and ecological analyses may be an important tools to identify hidden biodiversity among deep-water organisms such as bivalves.     

A guide to qualitative attribution methods for evaluation in conservation

Knowledge of what conservation interventions improve biodiversity outcomes, and in which circumstances, is imperative. Experimental and quasi-experimental methods are increasingly used to establish causal inference and build the evidence base on the effectiveness of interventions, but their ability to provide insight into how and under what conditions an intervention should be implemented to improve biodiversity outcomes faces limitations. A suite of attribution methods that leverage qualitative methods for causal inference is available but underutilized in conversation impact evaluation. This article provides a guide to 5 such qualitative attribution methods: contribution analysis, process tracing, realist evaluation, qualitative comparative analysis, and most significant change. It defines and introduces each method and then illustrates how they could be applied through a case study of community conservancies in Namibia. This guide provides examples of how qualitative attribution methods can advance knowledge of what works, in which contexts, and why in biodiversity conservation.     

Replacing monocultures with mixed-species stands: Ecosystem service implications of two production forest alternatives in Sweden

Whereas there is evidence that mixed-species approaches to production forestry in general can provide positive outcomes relative to monocultures, it is less clear to what extent multiple benefits can be derived from specific mixed-species alternatives. To provide such insights requires evaluations of an encompassing suite of ecosystem services, biodiversity, and forest management considerations provided by specific mixtures and monocultures within a region. Here, we conduct such an assessment in Sweden by contrasting even-aged Norway spruce (Picea abies)-dominated stands, with mixed-species stands of spruce and birch (Betula pendula or B. pubescens), or spruce and Scots pine (Pinus sylvestris). By synthesizing the available evidence, we identify positive outcomes from mixtures including increased biodiversity, water quality, esthetic and recreational values, as well as reduced stand vulnerability to pest and pathogen damage. However, some uncertainties and risks were projected to increase, highlighting the importance of conducting comprehensive interdisciplinary evaluations when assessing the pros and cons of mixtures.     

Aquatic Nuisance Species in the Great Lakes and Mississippi River Basin—A Risk Assessment in Support of GLMRIS

Environmental Management - The U.S. Army Corps of Engineers is conducting the Great Lakes and Mississippi River Interbasin Study to identify the highest risk aquatic nuisance species currently...     

In the eye of the stakeholder: The challenges of governing social forest values

This study examines which kinds of social benefits derived from forests are emphasised by Swedish stakeholders and what governance modes and management tools they accept. Our study shows that there exists a great variety among stakeholders’ perceptions of forests’ social values, where tourism and recreation is the most common reference. There are also differences in preferred governance modes and management where biomass and bioenergy sectors advocate business as usual (i.e. framework regulations and voluntarism) and other stakeholders demand rigid tools (i.e. coercion and targeting) and improved landscape planning. This divide will have implications for future policy orientations and require deliberative policy processes and improved dialogue among stakeholders and authorities. We suggest that there is a potential for these improvements, since actors from almost all stakeholder groups support local influence on governance and management, acknowledged and maintained either by the authorities, i.e. targeting, or by the stakeholders themselves, i.e. voluntarism.