Pathways of Mycobacterium ulcerans infection: a review

Buruli ulcer (BU), an often-deforming skin ulceration caused by Mycobacterium ulcerans (MU), is now considered by the World Health Organization to be the third most common mycobacterium infection. However, the reservoir of MU in the environment and the epidemiology of BU are poorly understood. The disease is prevalent in riverine, slow-flowing and swampy areas of several tropical and subtropical regions of the world, especially in West Africa where the disease is rapidly increasing in incidence. This paper presents a review of published literature concerning epidemiology of, transmission and susceptibility to MU infection. It considers several endemic natural environments and their influence on infection.     

Regulatory risk control through mandatory occupational safety and health (OSH) certification and testing regimes (CTRs)

Governments make increasing use of private certification and testing infrastructures as an alternative for traditional regulatory arrangements in several areas including occupational safety and health (OSH).This research, commissioned by the Dutch Inspectorate for Work and Income (IWI), concerns an analysis of risk control of four certification and testing regimes (CTRs) in the Netherlands, three mandatory regimes and one non-mandatory regime. The aim was to create a better understanding of problems that may arise in the risk control through such regimes and to identify critical processes and factors that can affect the risk control process.The results of this research are reported in two papers in this special issue (see also Zwetsloot et al., this issue). This one presents an analysis of the risk control at the regulatory level, and its associated critical factors and processes. These critical factors are clustered in four essential processes: the regulatory choice for a CTR, the definition of requirements for the auditing or inspection regime, the certification and testing processes as such, and the processes needed for the self-correcting or learning capability of the CTR. Jointly, these factors and processes form a framework for both the design and the evaluation of such regimes. The case studies clearly demonstrate that these critical factors may undermine the effectiveness of such regulatory practices. We propose that a further development of our framework should be used in the (re)design process for proposed and existing CTRs, and in the process of independent evaluation of such regimes.     

Analysis of transgenic Indian mustard plants for phytoremediation of metal-contaminated mine tailings

Transgenic Indian mustard [Brassica juncea (L.) Czern.] plants overproducing the enzymes gamma-glutamylcysteine synthetase (ECS) or glutathione synthetase (GS) were shown previously to have increased levels of the metal-binding thiol peptides phytochelatins and glutathione, and enhanced Cd tolerance and accumulation. Furthermore, transgenic Indian mustard plants overexpressing adenosine triphosphate sulfurylase (APS) were shown to have higher levels of glutathione and total thiols. These results were obtained with a solution culture. To better examine the phytoremediation potential of these transgenics, a greenhouse experiment was performed in which the transgenics were grown on metal-contaminated soil collected from a USEPA Superfund site near Leadville, Colorado. A grass mixture used for revegetation of the site was included for comparison. The ECS and GS transgenics accumulated significantly (P < 0.05) more metal in their shoot than wild-type (WT) Indian mustard, while the APS plants did not. Of the six metals tested, the ECS and GS transgenics accumulated 1.5-fold more Cd, and 1.5- to 2-fold more Zn, compared with wild-type Indian mustard. Furthermore, the ECS transgenics accumulated 2.4- to 3-fold more Cr, Cu, and Pb, relative to WT. The grass mixture accumulated significantly less metal than Indian mustard: approximately 2-fold less Cd, Cu, Mn, and Zn, and 5.7-fold less Pb than WT Indian mustard. All transgenics removed significantly more metal from the soil compared with WT Indian mustard or an unplanted control. While WT did not remove more metal than the unplanted control for any of the metals tested, all three types of transgenics significantly reduced the soil metal concentration, and removed between 6% (Zn) and 25% (Cd) of the soil metal. This study is the first to demonstrate enhanced phytoextraction potential of transgenic plants using polluted environmental soil. The results confirm the importance of metal-binding peptides for plant metal accumulation and show that results from hydroponic systems have value as an indicator for phytoremediation potential.     

Changes in hardwood forest understory plant communities in response to European earthworm invasions

European earthworms are colonizing earthworm-free northern hardwood forests across North America. Leading edges of earthworm invasion provide an opportunity to investigate the response of understory plant communities to earthworm invasion and whether the species composition of the earthworm community influences that response. Four sugar maple-dominated forest sites with active earthworm invasions were identified in the Chippewa National Forest in north central Minnesota, USA. In each site, we established a 30 x 150 m sample grid that spanned a visible leading edge of earthworm invasion and sampled earthworm populations and understory vegetation over four years. Across leading edges of earthworm invasion, increasing total earthworm biomass was associated with decreasing diversity and abundance of herbaceous plants in two of four study sites, and the abundance and density of tree seedlings decreased in three of four study sites. Sample points with the most diverse earthworm species assemblage, independent of biomass, had the lowest plant diversity. Changes in understory plant community composition were most affected by increasing biomass of the earthworm species Lumbricus rubellus. Where L. rubellus was absent there was a diverse community of native herbaceous plants, but where L. rubellus biomass reached its maximum, the herbaceous-plant community was dominated by Carex pensylvanica and Arisaema triphyllum and, in some cases, was completely absent. Evidence from these forest sites suggests that earthworm invasion can lead to dramatic changes in the understory community and that the nature of these changes is influenced by the species composition of the invading earthworm community.     

Frog occupancy of polluted wetlands in urban landscapes

Urban sprawl and the rising popularity of water-sensitive urban design of urban landscapes has led to a global surge in the number of wetlands constructed to collect and treat stormwater runoff in cities. However, contaminants, such as heavy metals and pesticides, in stormwater adversely affect the survival, growth, and reproduction of animals inhabiting these wetlands. A key question is whether wildlife can identify and avoid highly polluted wetlands. We investigated whether pond-breeding frogs are attempting to breed in wetlands that affect the fitness of their offspring across 67 urban wetlands in Melbourne, Australia. Frog species richness and the concentration of contaminants (heavy metals and pesticides) were not significantly related, even in the most polluted wetlands. The proportion of fringing vegetation at a wetland had the greatest positive influence on the number of frog species present and the probability of occurrence of individual species, indicating that frogs inhabited wetlands with abundant vegetation, regardless of their pollution status. These wetlands contained contaminant levels similar to urban wetlands around the world at levels that reduce larval amphibian survival. These results are, thus, likely generalizable to other areas, suggesting that urban managers could inadvertently be creating ecological traps in countless cities. Wetlands are important tools for the management of urban stormwater runoff, but their construction should not facilitate declines in wetland-dependent urban wildlife.     

Beyond data management: how ecoinformatics can benefit environmental monitoring programs

We review ways in which the new discipline of ecoinformatics is changing how environmental monitoring data are managed, synthesized, and analyzed. Rapid improvements in information technology and strong interest in biodiversity and sustainable ecosystems are driving a vigorous phase of development in ecological databases. Emerging data standards and protocols enable these data to be shared in ways that have previously been difficult. We use the U.S. Environmental Protection Agency’s National Coastal Assessment (NCA) as an example. The NCA has collected biological, chemical, and physical data from thousands of stations around the U.S. coasts since 1990. NCA data that were collected primarily to assess the ecological condition of the U.S. coasts can be used in innovative ways, such as biogeographical studies to analyze species invasions. NCA application of ecoinformatics tools leads to new possibilities for integrating the hundreds of thousands of NCA species records with other databases to address broad-scale and long-term questions such as environmental impacts, global climate change, and species invasions.     

The aerobic soil degradation of spinosad ‐ a novel natural insect control agent

Abstract

Spinosad is a natural product with biological activity against a range of insects including lepidoptera. It is comprised of two major components namely spinosyns A and D. The degradation of spinosad in soil under aerobic conditions was investigated using two U.S. soils (a silt loam and a sandy loam) which were treated with either ¹⁴C‐spinosyn A or ‐spinosyn D at a 2X use rate of 0.4mg/kg soil for spinosyn A and 0.1mg/kg for spinosyn D. Further samples of soil were pre‐sterilised prior to treatment in order to establish whether spinosyns A and D degrade abiotically. Flasks of treated soil were incubated in the dark at 25°C for up to one year after treatment.

HPLC and LC‐MS of soil extracts confirmed that the major degradation product of spinosyn A was spinosyn B, resulting from demethylation on the forosamine sugar. Other dégradâtes were hydroxylation products of spinosyns A and B, with hydroxylation probably taking place on the aglycone portion of the molecule. Half lives were similar for both spinosyns and were in the range 9–17 days, with longer half lives in the pre‐sterilised soils (128–240 days) suggesting that degradation was largely microbial.     

Safety rules: procedural freedom or action constraint?

The paper presents a partial classification of safety rules as constraints imposed from outside on the freedom of choice of individuals or companies. The classification is linked to the Reason model of skill-, rule-, and knowledge-based behaviour. The imposition of constraints is related to a number of criteria concerning the context and use of the rules to arrive at proposals for when and where to apply what type of rule. To illustrate the principles discussed an example is given of the rule from the Dutch Working Environment legislation concerning the requirement to use “current state of the art in prevention” in companies. The paper proposes providing procedural rule support to companies on how to meet the rule, in the form of a data bank of practicable solutions to health and safety problems.     

The Moral Considerability of Invasive Transgenic Animals

The term moral considerability refers to the question of whether a being or set of beings is worthy of moral consideration. Moral considerability is most readily afforded to those beings that demonstrate the clearest relationship to rational humans, though many have also argued for and against the moral considerability of species, ecosystems, and “lesser” animals. Among these arguments there are at least two positions: “environmentalist” positions that tend to emphasize the systemic relations between species, and “liberationist” positions that tend to emphasize the attributes or welfare of a particular individual organism. Already, this classic conflict provides for some challenging theoretical clashes between environmentalists and animal liberationists. The question of moral considerability is complicated, however, by recent developments in genetic engineering. Some animals, like pigs and fish, have been genetically modified by humans to grow organs that can then be transplanted into humans. If environmental arguments for the moral consideration of species are correct, then we are released from our obligations to morally consider those animals that we have genetically modified, since they are by their nature always an “invader species.” If, instead, the welfare of the animal is of penultimate importance, then there is a case for strengthening the moral considerability of GM animals over “naturally-occurring” animals, since they bear a closer relationship to humans. This would appear to be an intractable problem, a “bad marriage,” as Mark Sagoff once proposed. This paper argues that the case of invasive transgenic animals exposes weaknesses in this classic conflict, and particularly, in the framing of this conflict. To remedy this framing problem, this paper argues for a reconceptualization of the term “moral considerability,” instead urging a strong distinction between moral considerability, moral relevance, and moral significance.